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Facial expression recognition is linked to clinical and neurofunctional differences in autism
(2022)
Background: Difficulties in social communication are a defining clinical feature of autism. However, the underlying neurobiological heterogeneity has impeded targeted therapies, and requires new approaches to identifying clinically relevant bio-behavioural subgroups. In the largest autism cohort to date, we comprehensively examined difficulties in facial expression recognition, a key process in social communication, as a bio-behavioural stratification biomarker, and validated them against clinical features and neurofunctional responses.
Methods: Between 255 and 488 participants aged 6-30 years with autism, typical development and/or mild intellectual disability completed the Karolinska Directed Emotional Faces task, the Reading the Mind in the Eyes Task and/or the Films Expression Task. We first examined mean-group differences on each test. Then we used a novel intersection approach that compares two centroid and connectivity-based clustering methods to derive subgroups based on the combined performance across the three tasks. Measures and subgroups were then related to clinical features and neurofunctional differences measured using fMRI during a fearful face-matching task.
Results: We found significant mean-group differences on each expression recognition test. However, cluster analyses showed that these were driven by a low-performing autistic subgroup (~30% of autistic individuals who performed below 2SDs of the neurotypical mean on at least one test), while a larger subgroup (~70%) performed within 1SD on at least 2 tests. The low-performing subgroup also had on average significantly more social-communication difficulties and lower activation in the amygdala and fusiform gyrus than the high-performing subgroup.
Limitations: Findings of autism expression recognition subgroups and their characteristics require independent replication. This is currently not possible, as there is no other existing data set that includes all relevant measures. However, we demonstrated high internal robustness (91.6%) of findings between two clustering methods with fundamentally different assumptions, which is a critical pre-condition for independent replication.
Conclusions: We identified a subgroup of autistic individuals with expression recognition difficulties and showed that this related to clinical and neurobiological characteristics. If replicated, expression recognition may serve as bio-behavioural stratification biomarker and aid in the development of targeted interventions for a subgroup of autistic individuals.
G-protein-coupled receptors (GPCRs) comprise the largest transmembrane receptor family encoded in the human genome. GPCRs mediate the effect of a wide diversity of stimuli including light, odorants, ions, lipids, small peptides, and hormones. GPR182 is a GPCR for which no endogenous ligand has been identified yet. In the absence of an identified ligand, GPR182 remained poorly understood, and its biological functions had remained elusive. The presented work shows that GPR182 is highly and specifically expressed in microvascular endothelial cells. Phylogenetically, GPR182 is closely related to the atypical chemokine receptor 3 (ACKR3). Here, I show that GPR182 binds the chemokines CXCL10, -12 and -13. Similarly to other so-called atypical chemokine receptors, GPR182 is not coupled to G-proteins but is rather constitutively internalized following β-arrestin 2 recruitment. Consistent with potential scavenger functions, we detected increased concentration of the chemokines which bind the receptor in the plasma of Gpr182 deficient mice. Finally, we show that GPR182 plays an essential role in maintaining hematopoietic stem cells within the bone marrow niche. In summary, the data indicate that GPR182 is a novel member of the group of atypical chemokine receptors, which plays an important role in the chemokine/chemokine receptor network.
The Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) as well as the T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) are rare types of malignant lymphomas. Both NLPHL and THRLBCL are frequently observed in middle-aged men with THRLBCL presenting frequently with an advanced Ann-Arbor stage with B-symptoms and associated with more aggressive courses.3 However, due to the limited number of tumor cells in the tissue of both NLPHL and THRLBCL, limited numbers of studies have been conducted on these lymphomas and current results are mainly based on general molecular genetic studies.
In order to obtain a better understanding for these disease forms as well as possible changes in their nuclear and cytoplasmatic sizes, the following study relied on the comparison of the different NLPHL forms and THRLBCL in terms of nuclear size and nuclear volume. This was carried out using both 2D and 3D analysis. During the 2D analysis of nuclear size and nuclear volume no significant differences could be presented between those groups. However, the 3D analysis of NLPHL and THRLBCL pointed out a slightly enlarged nuclear volume in THRLBCL. Furthermore, the analysis indicated a significantly increased cytoplasmatic size of THRLBCL compared to NLPHL forms. Nevertheless, differences occurred not only between the tumor cells of both disease forms, but also the T cells presented a larger nuclear volume in THRLBCL. B cells, which were considered as the control group, did not demonstrate any significant differences between the different groups. The presented results suggest an increased activity of T cells in THRLBCL, which is most likely to be interpreted as a response against the surrounding tumor cells and probably limits the proliferation of the tumor cells. Based on these results, the importance of 3D analysis is also evident due to the fact that it is clearly superior to 2D analysis. For a better understanding of both disease forms, it is therefore recommended to use the 3D technique in combination with molecular genetic analysis in future research.
Background and Aim: Genome-wide association studies revealed a strong association between cardiovascular diseases (CVD) and clonal hematopoiesis of indeterminate potential (CHIP), highlighting one of its most common CHIP-driving mutations-TET2 (ten-eleven translocation 2), as a target for CHIP related CVD research. Our lab has established the generation of self-organizing cardiac organoids (SCO), which demonstrate the cellular composition and organization of the native human heart, and mimics human myocardial responses to stress stimulation. This project aims to examine whether SCOs would be an appropriate CHIP model and decipher promising drugs for cardiovascular CHIP treatment.
Methods: To study TET2-mutant cardiovascular CHIP, we set up the TET2 cardiac-CHIP model through a knockdown (KD) of TET2 in myeloid cells that infiltrated our lab-made SCO. Immunofluorescence and qPCR were performed to ascertain TET2-KD myeloid cell infiltration, SCO fibrosis, and apoptosis assessments. SCO fibrosis was further analyzed by immunofluorescence staining, and cardiac contractile frequency and amplitude were determined by calcium flux analysis. Finally, RNAseq was performed to analyze transcriptomic changes in drug/vehicle-treated TET2-KD myeloid cells and the TET2 cardiac-CHIP model.
Results: The TET2 cardiac-CHIP model resulted in significantly increased inflammation in SCO, accompanied by fibrosis and more cleaved Caspase-3, causing cardiomyocytes apoptosis and promoting the release of cTNT. The shortlisted drugs revealed a reduction of proliferation in TET2-KD myeloid cells, decreased pro-inflammatory cytokines, and a higher apoptosis level. Furthermore, the TET2 cardiac-CHIP model treated with selected drugs showed a remarkable decline in TET2-KD myeloid cell infiltration and pro-inflammation cytokines, cardiomyocyte apoptosis, fibrosis, and lowered cTNT levels, while drug control groups were not affected. Moreover, the drug treatment groups improved the heartbeat frequency and amplitude accessed by the calcium transient assay. RNAseq data also validated the above findings.
Conclusions & Discussion: Our results indicate that SCOs are an efficient pre-clinical model for studying and validating CHIP genes and drug interactions. Our data revealed that TET2-KD myeloid cells invade SCO and secrete pro-inflammatory cytokines, which promote apoptosis of cardiomyocytes and the release of cTNT. In this regard, our TET2 cardiac-CHIP model matches the inflammatory phenotype previously characterized in CHIP patients. Nevertheless, this phenotype could be rescued using positive drug candidates (Clopidogrel, R406, and Lanatoside C) selected by this project, emphasizing the significant value of our TET2 cardiac-CHIP model for drug screens and pre-clinical validation studies. Furthermore, among these three drug candidates, we found Lancatoside C, as proved by FDA/EMA, showed an unmet possibility for clinical therapeutic demand, insinuating potential benefit in repurposing Lanatoside C for the treatment of TET2-mutant cardiovascular CHIP.
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that typically begins in childhood and is associated with the cardinal symptoms of inattentiveness, hyperactivity, and impulsiveness. In a significant number of cases, ADHD persists into adulthood and leads to profound psychosocial impairment and costs to the population. The course of the disorder and the severity of psychosocial impairment are further influenced by the presence of comorbidities. The risk of developing psychiatric comorbidities such as affective disorders, personality disorders and substance use disorders is increased compared to the general population. Studies also indicate that ADHD is associated with a higher burden of somatic disorders such as obesity, diabetes mellitus, asthma and migraine. In the last decades, there has been a growing body of research that identified sex-related differences in ADHD, but there is still insufficient evidence on specific issues. In addition to the sex-ratio, which is more balanced in adulthood compared to childhood, there are also indications that differences exist at the symptom level and that the comorbid disorders that occur more frequently in ADHD also seem to differ in men and women, although the studies are not yet clear on this. Using resting-state analyses of functional magnetic resonance imaging (fMRI), we aimed to address the question of whether we can detect sex differences in ADHD and selected comorbidities (substance use disorder, depression, obesity) based on altered functional connectivity profiles. A central role for the pathogenesis of ADHD is the dysregulation of dopaminergic neurotransmission, specifically altered reward processing, as an expression of impaired impulse control. In the present study, we focused on a neuroanatomical hub, namely, the external part of the globus pallidus (GPe), which we defined as a "region of interest" for the analyses performed. There is growing evidence that the globus pallidus not only plays a role in the extrapyramidal motor system, but also integrates cognitive and reward-related information, functions that are impaired in ADHD. In a first step, we looked for sex differences in ADHD patients (n=137) and separately in healthy controls (HC) (n=45), then we compared a similar group of HC and ADHD patients to compare sex-differences in ADHD patients and HC. In a second step, we investigated whether the neural basis of comorbidity patterns differed between male and female patients. Analysis of the images of 182 participants was performed using the SPM-based CONN toolbox V 18.b. When comparing subjects with ADHD and HC, we observed an interaction between the GPe and the middle left temporal gyrus, with the effect being more pronounced in healthy subjects. When analyzing the large ADHD sample, an interaction between the GPe and the frontal pole/middle right frontal gyrus was observed. The connectivity between the GPe and the frontal and temporal brain areas appeared to be more pronounced in female ADHD patients than in males, with the sex-effect being reversed and more pronounced in healthy subjects. The results suggest that in patients with ADHD there is a loss of sex-specialization in GPe-connectivity. Males with ADHD and depression showed lower functional connectivity between the GPe and parts of the occipital cortex than females with ADHD and depression. To our knowledge, this is the first study to investigate sex-specific functional connectivity networks using a seed-based connectivity analysis of the external globus pallidus in adult ADHD patients with and without comorbidities. The study serves to improve our knowledge of GPe involvement in ADHD and sex-specific recruitment of this network. Taken as a whole, this study contributes to our understanding of the neurobiological correlates of ADHD and suggests possible differences between males and females with ADHD centered on altered connectivity with the GPe, helping to provide a different perspective on current research and new ideas for further studies.
Purpose: The aim of this work was to retrospectively identify prognostic factors for patients with neuroendocrine liver metastases (NELM) undergoing conventional transarterial chemoembolization (c-TACE), microwave ablation (MWA) or laser interstitial thermal therapy (LITT) and to determine the most effective therapy in terms of volume reduction and survival.
Method: Between 1996 and 2020, 130 patients (82 men, 48 women) were treated with c-TACE, 41 patients were additionally treated with thermoablative procedures.
Survival was retrospectively analyzed by using Kaplan-Meier-method. Prognostic factors were derived by using cox-regression. To find predictive factors for volume reduction due to c-TACE, a mixed-effects model was used.
Results: With c-TACE, an overall median volume reduction of 23.5 % was achieved. An average decrease of tumor volume was shown until the 6th c-TACE treatment, then the effect stopped. So, the median volume reduction off all lesions takes on a negative value from the 7th c-TACE intervention onwards. The mixed-effects model demonstrated that c-TACE interventions were most effective at the beginning of c-TACE therapy, and that treatment breaks longer than 90 days negatively influenced the outcome. For all patients evaluable for survival, Kaplan-Meier analysis showed a 1-year survival rate of 75 % and a 5-year survival rate of 36 %. Significant prognostic factors for survival were number of liver lesions (p = 0.0001) and therapeutical intention (p < 0.0001). Considering the clinical indication, 90.9 % of curative patients and 43.6 % of palliative patients responded to c-TACE therapy and thus could be submitted to a thermoablative procedure. Minor and one major complication occurred in 20.3 % of LITT and only in 8.6 % of MWA interventions. Complete ablation was observed in 95.7 % (LITT) and 93.1 % (MWA) of interventions
Conclusions: C-TACE is an effective treatment for volume reduction of NELM, however efficacy decreases after the 6th intervention and treatment breaks longer than 90 days should be avoided. With thermal ablation, a high rate of complete ablation was achieved and survival improved. Significant factors for survival were found and may be used as prognostic factors in the future.
Slack (sequence like a Ca2+ -activated K + channel; also termed Slo2.2, Kcnt1, or KNa 1.1) is a Na+ -activated K + channel that is highly expressed in the peripheral and central nervous system. Previous studies have shown that Slack is enriched in the isolectin B4binding, non-peptidergic subpopulation of C-fiber sensory neurons and that Slack controls the sensory input in neuropathic pain. Recent single-cell RNA-sequencing studies suggested that Slack is highly co-expressed with transient receptor potential (TRP) ankyrin 1 (TRPA1) in sensory neurons. By using in situ hybridization and immunostaining we confirmed that Slack is highly co-localized with TRPA1 in sensory neurons, but only to a minor extent with TRP vanilloid 1. Mice lacking Slack globally or conditionally in sensory neurons (SNS-Slack─/─ ), but not mice lacking Slack conditionally in neurons of the spinal dorsal horn (Lbx1-Slack─/─ ), displayed increased pain behavior after intraplantar injection of the TRPA1 activator allyl isothiocyanate. Patch-clamp recordings with cultured primary neurons and in a HEK-293 cell line transfected with TRPA1 and Slack revealed that Slack-dependent K + currents are modulated in a TRPA1-dependent manner. Taken together, these findings highlight Slack as a modulator of TRPA1-mediated activation of sensory neurons.
Furthermore, we investigated the contribution of Slack in the spinal dorsal horn to pain processing. Lbx1-Slack ─/─ mice demonstrated normal basal pain sensitivity and Complete Freund’s Adjuvant-induced inflammatory pain. Interestingly, we observed a significantly increased spared nerve injury (SNI)-induced neuropathic pain hypersensitivity in Lbx1-Slack ─/─ mutants compared to control littermates. Moreover, we tested the effects of pharmacological Slack activation in the SNI model. Systemic and intrathecal, but not intraplantar administration of the Slack opener loxapine significantly alleviated SNI-induced hypersensitivity in control mice, but only slightly in Lbx1Slack ─/─ mice, further supporting the inhibitory function of Slack in spinal dorsal horn neurons in neuropathic pain processing.
Altogether, our data suggest that Slack in sensory neurons controls TRPA1-induced pain, whereas Slack in spinal dorsal horn neurons inhibits peripheral nerve injury induced neuropathic pain. These data provide further insights into the molecular mechanisms of pain sensation.
The visual system encompasses about 20% of the cerebral cortex1 and plays a pivotal role in higher-order cognitive processes such as attention and working memory. Cognitive impairments constitute a central role in neuropsychiatric disorders such as schizophrenia (SZ). Impairments are described in visual perceptual processes including contrast, and emotion discrimination as well as in the ability to identify visual irregularities and in higher-order cognition like visual attention and working memory. Furthermore, perceptual and higher-order cognitive processes are part of the Research Domain Criteria (RDoC) project that aims to develop dimensional and transdiagnostic constructs with defined links to specific brain circuits.Therefore, the detailed study of the visual system using functional magnetic resonance imaging (fMRI) is essential to understand the processes in healthy individuals but also in populations with neuropsychiatric disorders. Visual mapping techniques include functional localizer tasks to map functionally defined regions like the fusiform face area (FFA), retinotopic mapping to map specific brain regions that are retinotopically organized in full, and visual-field localizer paradigms to define circumscribed areas within retinotopically organized areas.Thus, the latter allow studying local information processing in early visual areas. Despite advances in neuroimaging techniques, analyses of fMRI data at the group-level are impeded by interindividual macroanatomical variability. This reduces the reliability to accurately define visual areas particularly at the group-level and decreases statistical power. Single-subject based solutions for this problem are not appropriate. Analyses after volume-based alignment (VBA) and primary surface-based analyses without macroanatomical alignment do not increase macroanatomical correspondence sufficiently. Cortex-based alignment (CBA) approaches are recommended as an alternative technique to address this obstacle. However, CBA has not been evaluated for visual-field localizer paradigms. Therefore, we aimed to evaluate potential benefits of CBA for an attention-enhanced visual field localizer paradigm that maps circumscribed regions in retinotopically organized visual areas. Since previous studies solely compared surface-based data before and after CBA, we aimed to compare all three techniques: (1) a volume-based alignment (VBA), (2) a surface-based data set without (SBAV) and (3) a surface- based data set with macroanatomical alignment (CBA). Furthermore, we sought to define regions of interest (ROI) that subsequently can be used for the study of higher-order cognitive processes. Also, we aimed to investigate whether CBA facilitates the study of functional asymmetries in early visual areas as these were described in previous studies. Healthy volunteers (n=50) underwent fMRI in a 3- Tesla Siemens Trio scanner while performing an attention-enhanced visual field localizer paradigm. Our task consisted of a series of flickering, black-and white colored checkerboard stimuli that randomly appeared at one of four locations comprising the participants’ visual quadrants. In 25% of the trials the centrally located squares briefly changed their color to yellow (target trial). Participants had to indicate detection of a target by button press. Data analysis was conducted using Brain Voyager 20.6. Our approach for macroanatomical alignment included a high-resolution, multiscale curvature driven alignment procedure minimizing interindividual macroanatomical variability. Here, each folding pattern was aligned to a dynamically updated group average. Thus, we counteracted a possible confounding effect of a suboptimal selection of an individual target brain with a folding pattern deviating considerably from the cohort average. Group ROIs after CBA showed increased spatial consistency, vertical symmetry, and an increase of size. This was corroborated by an increase in the probability of activation overlap of up to 86%. CBA increased macroanatomical correspondence and thus ameliorated results of multi-subject ROI analyses. Functional differences in the form of a downward bias in visual hemifields were measured with increased reliability. In summary, our findings provide clear evidence for the superiority of CBA for the study of local information processing in early visual cortex at the group-level. This approach is of relevance for the study of visual dysfunction in neuropsychiatric disorders including schizophrenia as they show impaired visual processing that in turn impacts higher-order cognitive processes and in consequence functional outcome. In addition, our attention-enhanced visual field localizer paradigm will be useful for machine learning approaches such as multivariate pattern analysis decoding local information processes and connectivity patterns.
Cardiovascular disease (CVD) is the leading cause of death in the western world. Aging as the major risk factor for the development of CVD leads to structural changes in the heart and the vasculature. In addition to endothelial cells, mural cells, including smooth muscle cells and pericytes, form the vascular wall. Pericytes are defined as the perivascular cells located in the basement membrane of the capillaries, which are the smallest components of the vascular system and ensure the gas exchange in the tissue. In the different parts of the terminal vascular bed, pericytes receive different phenotypes and organ-specific functions. In addition to the stabilization of the vascular wall, pericytes are relevant for the formation of new vessels. Due to their potential of multipotent stem cells, pericytes can differentiate into different cell types and thus take a position in developmental processes. Pericytes play a crucial role in the development and diseases of the vascular system. Moreover, pericyte coverage is reduced in the aged heart. Nonetheless, the function of pericytes in the heart and their importance during cardiac aging is not completely understood.
To study the pericyte population in the aging heart, we have performed single-nucleus RNA-sequencing analysis comparing hearts from 12-weeks-old (young) and 18-month-old (old) mice. The detailed analysis of 336 differentially expressed genes (DEG) revealed that Rgs5 is downregulated in aged pericytes. Regulator of G-protein signaling 5 (RGS5), an established marker for pericytes, is involved the regulation of the blood pressure and in the formation of various cardiovascular diesases, including cardiac hypertrophy, myocardial infarction and atherosclerosis. We have furthermore confirmed this observation in vivo. Gene ontology (GO) analysis of DEG revealed that aged pericytes are characterized by the downregulation of genes involved in cell adhesion. Further, we have performed cell biology approaches using human brain vascular pericytes (hBVP) to investigate the role of Rgs5 in pericytes in vitro. Efficient knockdown of RGS5, although has no effect on cellular metabolism, viability and endothelial permeability, induces a reduction of pericyte adhesion to both a gelatine matrix and endothelial cells in a 3D matrigel culture. This was associated with the formation of filopodia. The altered phenotype suggested a changing identity of the pericytes. We could confirm that a loss of RGS5 causes a decreased expression of the pericyte markers PDGFRb and NOTCH3 and also leads to an overexpression of COL1A1, a fibroblast marker.
Together, our findings suggest that RGS5 is required for pericyte adhesion to endothelial cells and its downregulation in the aged mural cells could explain the reduction of pericyte coverage in the aged hearts. Further, RGS5 may be the key regulator for pericyte identity, as pericytes show an altered expression profile of cellular markers. The dedifferentiation of pericytes to a more fibroblast-like cell type could explain the increased fibrosis during age-related cardiac remodeling. We believe that RGS5 is a great candidate to explore and study the molecular mechanisms that regulate pericyte function in the heart, both in homeostasis and during aging.
Many countries have restricted public life during the SARS-CoV2 pandemic. As related measures limited the access to sports facilities, this dissertation aimed (1) to examine changes in physical activity (PA) and well-being in affected countries, and (2) to determine the effectiveness of a digital home exercise program in this context.
Part 1 (PA/well-being) of the dissertation was a digital survey administered in 14 countries. Participants reported a 41 - 42% reduction of PA (NPAQ-SF) during restrictions (n=13,503 valid responses). Compliance with international PA guidelines decreased by nearly 19%. Mental well-being declined substantially (n=14,975 responses; 68.1 to 51.9 points on the WHO5 index) and the proportion of individuals at risk of depression tripled (14.2% to 45.2%). Physical well-being (SF-36 Pain) decreased slightly (85.8% to 81.3%). About two thirds (68.1%) of the respondents reported being interested in digital home exercise.
For Part 2 (digital home exercise) of the dissertation, an international multicenter randomized, controlled trial was performed allocating healthy adults (n=763; 33±12 years) to an intervention (IG) or control (CG) group. In contrast to the CG, the IG was offered live-streamed home exercise for four weeks. Subsequently, both groups had access to pre-recorded workouts for another four weeks. Outcomes were measured weekly using validated questionnaires. Mixed-models data analyses revealed an up to 1.65-fold (95% CI: 1.4-1.94; week 1) increase of PA relative to the CG. Moreover, small improvements in exercise motivation (SKK scale), psychological well-being (WHO-5 index), sleep quality (MOS Sleep Scale), and anxiety symptoms (GAD-7 Scale) were observed for IG.
The results of this dissertation suggest that public life restrictions associated with the pandemic had significant adverse effects on movement behavior and well-being. Digital home exercise can help to maintain and/or increase health- beneficial PA and well-being and may hence represent a supportive element of viral containment efforts.
Background: During ECMO therapy ischemia of the limbs or internal organs are potential lethal complications. This study analyzed incidence and type of ischemic complications during ECMO therapy, divided in limb, mesenteric, cardiac and neurological ischemia.
Methods: In this single-center retrospective observational study data from 348 patients treated with veno-venous, veno-arterial or veno-venous-arterial ECMO at the Asklepios Klinik Langen between April 1st 2011 and March 31st 2020 was screened. 321 patients with diagnosis of acute respiratory distress syndrome, cardiogenic or septic shock were included.
Primary outcome variable was type of ischemic complication. Further variables were serum lactate levels 24h before and immediately after diagnosis of the ischemic complication, duration of ICU and hospital stay, ECMO therapy and duration of invasive ventilation and arterial blood gas analysis on day of admission to the ICU. Age, sex, ECMO mode, diagnosis, SAPS II, SOFA score, hospital mortality, the use of renal replacement therapy and tracheotomy, the occurrence of infections during the ICU stay and the need of CPR before ECMO implantation were recorded as well.
Results: 62/321 patients (19.3%) were diagnosed with an ischemic complication. Most common areas were limbs (n=32) and mesenteric ischemia (n=21). Patients who were diagnosed with a septic shock had the highest rate of ischemic complications (36.2%). In VV mode there was a difference in survival between patients with and without ischemic complication (p=0.025). Using multivariate logistic regression, age ≥50 years (p=0.029; OR=2.793; CI 1.109 – 7.033), use of hemodialysis (p=0.003; OR=3.283; CI=1.513 – 7.124) and initial diagnosis of a septic shock (p=0.049; OR=2.144; CI=1.003 – 4.583) could be identified as predictors for ischemic complications.
Conclusions: Ischemic complications are frequent during ECMO therapy. An age of at least 50 years, the use of hemodialysis and diagnosis of a septic shock were predictors of ischemic complications. No correlation between ECMO mode and ischemic complications was found. An influence of ischemic complications on survival could be found only in patients treated with VV mode.
Background: Increasing numbers of patients surviving malignant bone tumors around the knee joint have led to an increasing importance to investigate long-term results. This study assessed the long-term results of rotationplasty after resection of malignant bone tumors regarding functional outcome and quality of life to allow better comparison with other treatment options in bone cancer treatment.
Procedure: 60 participants who underwent rotationplasty due to bone cancer took part in this multicentric questionnaire- based study. The long-term functional outcome was measured by the Musculoskeletal tumor society score (MSTS) and the Tegner activity level scale. The health-related quality of life (HRQL) was assessed by using the Short Form Health Survey (SF-36).
Results: Patients treated with rotationplasty (median follow- up of 22 years, range 10–47 years) regained a high level of activity (median MSTS score of 24). Even a return to high level sports was possible (mean Tegner activity level scale of 4). Duration of follow-up did not influence the functional outcome. HRQL scores were comparable to the general German popula tion. Concerns of psychological problems due to the unusual appearance of the rotated foot have not been confirmed.
Conclusion: Rotationplasty can be a good alternative to en- doprosthetic replacement or amputation, either as primary surgery or as a salvage procedure. Especially for growing children and very active patients rotationplasty should be considered.
Gait analysis as a clinical examination method has been increasingly used in recent years. In particular, the external knee adduction moment was often used as a surrogate measure for internal medial knee joint loading, e.g., in elderly individuals with medial knee osteoarthritis. Therefore, the knee adduction moment is also associated with the progression of knee osteoarthritis. Children and adolescents with valgus malalignment have been found to experience a reduced external knee adduction moment, but internal knee joint contact forces, particularly in the lateral compartment, were not previously studied.
First, medial and lateral knee joint contact forces were studied using muskulosceletal modeling in young individuals with and without valgus malalignment treated by guided growth. In addition, a systematic literature review was conducted to explore the relationship between external joint moments and internal joint contact forces. Finally, this relationship was investigated in children and adolescents with and without valgus malalignment. Furthermore, we examined whether statistical models could be determined to accurately predict internal knee joint contact forces by commonly used parameters from three-dimensional gait analysis, such as external knee joint moments.
It was found that guided growth normalized knee joint contact forces after treatment. In addition, the static radiographic mechanical axis angle correlated better after the treatment when the patients showed a typical limb alignment compared to the correlation before guided growth with the valgus malalignment due to compensating strategies during gait. Furthermore, the systematic review showed that the peak medial knee joint contact force was best predicted by the knee adduction moment and even better together with the knee flexion moment in the first half of stance. However, for the second half of stance of the medial knee joint contact force and the entire stance of the lateral knee joint contact force, only low correlations with knee adduction and/or flexion moment were found. Finally, statistical models could be determined with high accuracy for both medial and lateral knee joint contact force, for both peaks in the first and second half of stance, and for both study groups of children and adolescents with and without valgus malalignment by including knee adduction and flexion moment as predictors.
These results demonstrate the importance of examining not only the external knee adduction moment but also the knee flexion moment and, even better, the medial and lateral knee joint contact forces when evaluating knee joint loading. With these statistical models, clinicians can predict the medial and lateral knee joint contact forces without the need to perform musculoskeletal simulations and can therefore use standard three-dimensional gait analysis parameters such as knee adduction and flexion moment. This can improve guided growth treatment in children and adolescents with valgus malalignment with regard to implantation or explantation of the growth restricting plates or to rebound. Instrumented gait analysis could be particularly helpful in borderline cases, as kinematic compensation mechanisms during gait may play a role and the static radiograph alone does not provide information about dynamic joint loads.
Aortic valve (AV) and root replacement with composite graft and re-implantation of coronary arteries described first by Bentall and de Bono in 1968, is considered as a standard operation for treatment of different pathologies of the AV and aortic root. In centres where aortic valve and root repair techniques and Ross operation are well established, generally severely diseased patients remain indicated for this procedure. The aim of this study was to evaluate the early and long-term outcomes after Bentall-De Bono (BD) procedures in high-risk population with complex pathologies and multiple comorbidities.
Between 2005 and 2018, a total of 273 consecutive patients (median age 66 years; 23 % female) underwent AV and root replacement with composite-graft in so called button technique. We divided our population in the following groups: 1. acute type A aortic dissection group (ATAAD) (n = 48), 2. endocarditis group (n = 99) and 3. all other pathologies group (n = 126). The surgery has been per- formed emergent/urgent in 131 patients (49 %) and in 109 cases (40%) as a reoperation. Concomitant surgery was required in 97 patients (58%) and 167 pa- tients (61%) received a biological composite-graft.
Follow-up was completed in 96% (10 patients lost to follow-up) with a mean of 8.6 years (range 0.1-15.7 years), counting a total of 1450 patient-years. Thirty- day mortality was 17% (46 patients). The overall estimated survival in 5 and 10 years was 64% ± 3%) and 46% ±4 %). Group comparison showed a significant difference in favour of patient from the dissection group (p = 0.008). Implantation of a biological valve graft was associated with lower survival probability (p < 0.001). There was no significant difference in the freedom of reoperation rate between the groups. The same applies for freedom of postoperative endocarditis, thromboembolic events, and aortic prosthesis dysfunction. According to the uni- variate and multivariate logistic regression analysis primarily postoperative neu- rological dysfunction (OR 5.45), hypertension (OR 4.8) peripheral artery disease (OR 4.4), re-exploration for bleeding (OR 3.37) and postoperative renal replace- ment therapy (OR 3.09) were identified as leading predictors of mortality.
In conclusion, the BD operation can be performed with acceptable short- and long-term results in high-risk patients with complex aortic pathologies in a centre with well-established AV repair and Ross operation program.
While B-cell acute lymphoblastic leukaemia (B-ALL) can be described as the leukaemia of childhood, chronic myeloid leukaemia (CML) mostly develops in elderly individuals. Understanding and utilising mechanisms involved in the development and persistence of these leukaemias as possible targets for treatment strategies has received particular interest. Processes that happen in the vicinity of the cancerous cells themselves could influence cancer growth and behaviour and hence can serve as novel targets, leading to the development of two-pronged therapies that act both on leukaemic cells directly as well as their niche. The niche in the case of leukaemia is the bone marrow microenvironment (BMM) where these cells are not only generated but also instructed and protected. As the BMM is situated inside bones that undergo drastic changes and growth processes during the ageing process, the BMM itself is also being altered throughout life. These alterations and the very process of expansion itself may therefore also provide distinct regulatory influences on the cells (healthy or malignant) that are generated inside this niche, leading to the question: Does the age of the bone marrow microenvironment differentially influence the development of (“childhood”) B-ALL versus (“adult”) CML by the release of cytokines?
In previous studies by the host-laboratory the age distribution of B-ALL versus CML in a murine transduction/ transplantation model could be recapitulated; young mice which received the same number of leukaemia-initiating cells as their old counterparts died significantly earlier of B-ALL while showing a significantly delayed clinical course, when they were suffering from CML. The tumour load and other leukaemia-associated parameters also showed a clear disposition towards preferential induction of CML in elderly and B-ALL in younger mice.
In this project we could support the hypothesis that the age of the BMM differentially influences the proliferation of leukaemic cells and thereby the development and persistence of different types of leukaemias by utilising different in vitro culture experiments. Specifically, we could show that young (compared to old) bone marrow
11 stroma cells (BMSC) support the growth of (BCR-ABL1+) B-ALL cells both in a direct, cell on cell co-culture setting, as well as in young BMSC-derived conditioned medium. This supports the hypothesis that varying factors are differentially released from a young versus an old BMM and influence the growth of the leukaemia cells. The opposite might be true for CML cells (BCR-ABL1+ 32D cells); BMSC obtained from old animals showed a tendency to support their growth more profoundly than cells acquired from young animals.
Possible proteins responsible for the distinct regulation of myeloid versus lymphatic leukaemic cells by young versus old BMM have also been studied. We investigated C-X-C motif chemokine 13 (CXCL13) and growth differentiation factor 11 (GDF11) in their effect on leukaemia cells, as both proteins having previously been described to have tumour-modelling properties and age-dependent levels (see below).
We identified an increased secretion of CXCL13, a B-cell chemotactic factor, into conditioned medium from young versus old BMSC. In accordance with this we found migration of B-ALL cells towards BMSC from young compared to old mice to be improved, while adhesion of both B-ALL and CML cells to young versus old BMSC did not show any differences. By blocking CXCL13 the proliferation-supporting effect of young BMSC on B-ALL cells could be diminished. Similar effects could be demonstrated by blocking GDF11.
In the case of CML cells we could observe the opposite effect; blocking CXCL13 and GDF11 increased their proliferation in a co-culture with BMSC. This supported our hypothesis that both cytokines differentially regulate B-ALL and CML behaviour. After the completion of this thesis, another member of the host-laboratory convincingly demonstrated the role of BMM age in the regulation of B-ALL via CXCL13 signalling (see discussion).
In haploidentical stem cell transplantation (SCT), achieving a balance between graft versus host disease (GvHD), graft versus leukemia effect (GvL) and bridging the vulnerable phase of aplasia against viral infections is still a challenge. Graft preparation strategies attempt to achieve this balance by removing and retaining harmful and helpful cells. At this point it is known that T cell subpopulations hold different properties concerning GvHD promotion and immunocompetence towards pathogens. CD45RA+ naïve T cells show the greatest, while CD45RO+ memory T cells show less alloreactive potential but provide immunocompetence. CD45RA depletion is a promising new approach to graft processing that potentially combines GvHD prevention, GvL promotion and transfer of immunological competence by removing potentially harmful CD45RA+ naïve T cells and retaining CD45RO+ memory cells. This work focused on manufacturing CD45RA-depleted grafts within a one- or two-step approach, as well as a feasibility assessment of the process and the establishment of a 10-color fluorescence activated cell sorting (FACS) measurement panel for clinical-scale graft generation. CD45RA depletions were conducted from granulocyte-colony stimulated factor (G-CSF) mobilized peripheral blood stem cells (PBSC) applying two different strategies, direct depletion of CD45RA+ cells (one-step approach), or depletion following preceding CD34 selection. A 10-color FACS measurement panel was established ensuring quality control and enabling preliminary data acquisition on CD45RA co-expression for cell loss estimations. Residual virus-specific T cells after depletion were measured using MHC multimers. It was observed that the depletion antibody occupied the cell binding sites, resulting in insufficient binding of the fluorescent dye for subsequent FACS measurement. Therefore, three FACS antibodies were tested and compared, and CD45RA-PE (clone:2H4) was found to be the best choice for reliable cell detection. To further characterize residual T cells, two homing markers, CD62L and CCR7, were compared, with particular attention paid to the expression of the surface markers after cooling. Both markers were complementary to each other, resulting in the decision to include an additional FACS measuring tube whenever samples are cooled or further T cell characterization is needed. With a median log depletion of -3.9 (one-step) and -3.8 (two-step) data showed equally efficient removal of CD45RA+CD3+ T cells for both approaches. Close to complete B cell removal was obtained without additional reagent use. However, also close to complete NK cell loss occurred due to high CD45RA co-expression. Stem cells recovered at a median of 52% (range: 49.7 - 67.2%) after one-step CD45RA depletion. CD45RO+ memory T cells recovery was statistically not differing between both approaches. Virus-specific T cells were detectable after depletion, suggesting that virus-specific immunocompetence is transferable. In conclusion, CD45RA depletions are equally feasible for both approaches when performed from fresh, non-cryopreserved starting products, show reliable reduction of CD45RA and B cells, but also result in co-depletion of NK cells. Stem cell recovery and NK cell losses must be considered carefully especially regarding overcoming HLA barriers, pathogen protection during aplasia, early engraftment an GvL. Therefore, a combination of CD45RA-depleted products with already established other processing methods to ensure sufficient stem and NK cells is desirable to allow high clinical flexibility.
Despite major improvements of the therapy, many B-cell Non-Hodgkin’s lymphoma (B-NHL) entities still have a poor prognosis. New therapeutic options are urgently needed. Therefore this study sets out to investigate oncogenic signalling pathways in the two B-NHL entities mantle cell lymphoma (MCL) and diffuse large B-cell lymphoma (DLBCL) in order to define new potential therapeutic targets.
MCL cells overexpress the anti-apoptotic protein BCL-2, thereby they evade apoptosis. With venetoclax, the first-in-class BCL-2 specific inhibitor was approved and achieved good response rates in MCL. However, some cases display intrinsic or acquired resistance to venetoclax. In order to improve the therapy, this study aimed to identify genes which confer sensitivity or resistance towards venetoclax upon their respective knockout. To this end, a genome-wide CRISPR/Cas9-based loss-of-function screen was conducted in the MCL cell line Maver-1. The E3 ubiquitin
ligase MARCH5 was identified as one of the top hits conferring sensitivity
towards venetoclax upon its knockout. This finding was validated in a competitive growth assay including two more MCL cell lines, Jeko-1 and Mino. MARCH5 knockout also sensitised Jeko-1 cells towards venetoclax even though this cell line was insensitive towards venetoclax in its wild-type form. Using BH3 profiling, an increased dependency on BCL-2 of MARCH5-depleted cells confirmed this finding. The sensitisation was found to be based on induction of apoptosis upon MARCH5 knockout and to an even higher extent upon additional treatment of MARCH5-depleted cells with venetoclax. As already described for epithelial cancer entities, the BCL-2 family members MCL-1 and NOXA were upregulated in MCL cell lines upon MARCH5 knockout. This led to the hypothesis that MARCH5 is a potential
regulator of intrinsic apoptosis with NOXA as a key component. A competitive growth assay with MARCH5 and NOXA co-depleted cells revealed a partial reversion of the BCL-2 sensitisation compared to MARCH5 knockout alone. Furthermore, mass spectrometry-based methods were used to gain more insight into other cellular pathways and networks which might be regulated in a MARCH5-dependent manner. In an interactome analysis, proteins which regulate mitochondrial morphology, such as Drp-1 were identified as MARCH5 interactors. Besides this expected finding, interaction between MARCH5 and several members of the BCL-2 family as well as a potential connection between MARCH5 and vesicular trafficking was discovered. As expected, an ubiquitinome analysis of MARCH5-depleted cells revealed decreased levels of MCL-1 and NOXA ubiquitination. Additionally, a potential role of MARCH5 in the ubiquitination of several members of the cell cycle regulatory
pathway was discovered. Based on the broad spectrum of cellular pathways which seem to be regulated in a MARCH5-dependent manner, it was hypothesised that MARCH5 primarily regulates BCL-2 family members which in turn regulate intrinsic apoptosis on the one hand and additionally are involved in the regulation of various other pathways on the other hand.
In summary, this study provides insight into a MARCH5-dependent MCL1-1/NOXA axis in MCL cells and potential implications into related cellular processes.
In addition to the anti-apoptotic pathways described above, B-cell receptor (BCR) signalling is known to provide a pro-survival signal to both normal and malignant B-cells. Targeting the BCR signalling pathway therefore is a promising therapeutic target for B-cell malignancies. In order to gain more insight into the differential modes of BCR signalling of ABC- and GCB-DLBCL cells, genes/proteins which displayed differential essentiality in ABC- and GCB-DLBCL cells were aimed to be defined. Consequently, data sets from a CRISPR/Cas9-based loss-of-function screen
were re-analysed. SASH3 was identified as a gene which was essential for GCB- but not for ABC-DLBCL cells. Since this protein is known to be involved in T-cell receptor (TCR)-signalling, SASH3 was assumed to play a potential role in BCR signalling as well and was therefore investigated in more detail. A competitive growth assay confirmed that SASH3 knockout was toxic exclusively for GCB-DLBCL cell lines. An interactome analysis in ABC- and GCB-DLBCL cells revealed interaction between SASH3 and many components of the proximal BCR signalling pathway as well as several downstream signalling pathways such as the PI3K or the NF-ΚB pathway.
An integration of the interactome with data from the CRISPR/Cas9-based loss-offunction screen revealed differential essentiality of the SASH3-interacting proteins in ABC- and GCB-DLBCL cells. It was hypothesised that SASH3 might regulate PI3K signalling on which GCB- but not ABC-DLBCL cells are known to dependent. Discontinuation of the regulation of PI3K signalling could therefore be exclusively toxic to GCB-DLBCL cells.
Taken together, this study describes a subtype-specific dependency of GCB-DLBCL cells on SASH3. Furthermore, the SASH3 interactome has been investigated in B-cells for the first time, thereby highlighting a potential role in proximal BCR signalling and involvement in specific BCR-related downstream signalling pathways.
The postthrombotic syndrome (PTS) is beside the venous thromboembolism (VTE) recurrence and chronic thromboembolic pulmonary hypertension (CTEPH) a long-term adverse outcome and chronic complication of deep vein thrombosis (DVT) in the lower extremities and can occur in up to 20–50% of patients within 2 years after DVT. The prevalence of PTS in the adult population is expected to increase due to the growing incidence of VTE in the elderly. Although not life threatening it can impose significant morbidity and can be associated with a negative impact on quality of life associated with disease severity. From an economic point of view, PTS is an important predictor of increased health care costs after VTE.
Factors potentially related to the development of the PTS are older age, obesity, a history of previous ipsilateral DVT, iliofemoral location of the current thrombosis, failure to promptly recover from the acute symptoms and insufficient quality of oral anticoagulant therapy. Furthermore, it is known that the severity of PTS correlates with the location of the DVT, the more proximal the more severe.
PTS induces a range of symptoms and clinical signs, which can be assessed in different scales. The Villalta scale is one of the most suitable scales for defining the presence and severity of subjective symptoms and physical signs of PTS.
In the last century, various therapeutic strategies have been developed to prevent mortality due to VTE or long-term morbidity due to PTS.
Conservative treatment today consists of anticoagulation - usually using direct oral anticoagulants - and compression therapy. One of the first invasive treatments with the aim of thrombus removal was surgical venous thrombectomy by Läwen in 1938. Mahorner and Fontaine improved the technique in the 1950s combining it with a course of anticoagulant treatment to prevent rethrombosis and PTS.
Mechanical thrombectomy by the use of Fogarty balloons, which started in 1963, or the creation of a transient arteriovenous fistula, performed since 1974, are now no longer recommended due to the high invasiveness, risk of fatal intraoperative embolism and a high rethrombosis rate.
In current practice, early thrombus removal mainly relies on the use of catheter-directed pharmacologic thrombolytic therapy. Another approach currently is the endovenous, device-driven thrombectomy and stenting in case of venous obstruction. There is an ongoing broad discussion as to whether these invasive therapies should be offered to patients with iliofemoral thrombosis (IFT), which remains controversial.
IFT, the major target for endovenous thrombectomy respectively pharmacologic thrombolytic therapy, is not enough represented in current literature because the used definition of proximal DVT does not necessarily include the iliac veins. In consequence, it may not be representative enough concerning questions like prevalence and severity of PTS or the effects on quality of life.
The present registry – the Iliaca-PTS registry – addresses exactly these patients and tries to answer these questions. The data of 85 patients who had suffered an IFT in the past were evaluated in the prospective registry documenting the severity of PTS, the occurrence of iliac vein compression syndrome in left-sided IFT and quality of life. A significant predictor for the development of severe PTS or venous claudication in our patient population is a high BMI.
The results of this registry show that IFT is frequently observed and only ten percent develop a moderate or severe PTS respectively venous claudication. In conclusion, the conservative treatment strategy with optimal effective anticoagulant therapy can lead to a low incidence of PTS and a high quality of life.
Treatment response to neoadjuvant chemoradiotherapy (nCRT) varies considerably among individual patients in advanced rectal cancer indicating a clinical need for markers to predict treatment efficacy and to stratify patients for future personalized treatment. In recent years, there is a tremendous evidence on a pivotal impact of immune components on the development/pathogenesis of cancer and on mediating response to radiation and chemotherapy. Moreover, liquid biopsy biomarkers have become increasingly attractive to predict treatment response because they are easy to collect, reflect information on different aspects of tumor biology and can be accurately measured by standardized methods.
This study aimed to investigate the peripheral blood and tumor tissue immune cell contexture in patients with rectal adenocarcinoma treated with nCRT and chemotherapy (CT) within a prospective randomized phase II CAO-ARO-AIO-12 trial, conducted in the context of DKTK (Deutsches Konsortium für translationale Krebsforschung) and FCI (Frankfurt Cancer Institute), to address the questions whether peripheral blood and/or primary tumor immune contexture predict for treatment response, were modulated by nCRT/CT and correlated with each other. By this, immune cell components were assayed by flow cytometry from peripheral blood mononuclear cells (PBMCs) at baseline, day 43, and pre-surgery of 22 patients treated with nCRT/CT and subsequently correlated with pathologic treatment response. Immunophenotyping was performed applying different staining panels covering myeloid immune cells and human leukocyte antigen (HLA) molecules, T lymphocyte subpopulations and programmed cell death (PD)-1 protein expression and regulatory T cells (Tregs). In addition, tumor tissue samples from pre-therapeutic biopsies and surgical specimens were analyzed by immunohistochemistry and multiparametric immunofluorescence.
The present prospective study raised the following issues. First, peripheral lymphocytes seem to play a crucial role in the nCRT/CT mediated systemic anticancer immunological response. Second, among the various lymphocyte subsets, peripheral blood, but not tissue resident T lymphocytes seem to play a central role in predicting treatment response. By this, baseline blood phenotyping revealed a lymphocyte distribution with high numbers of (CD3+CD4+) T helper cells and low numbers of (CD3+CD8+) cytotoxic T cells expressing PD1, activation markers GranzymeB, perforin and HLA-DR to be associated with an improved response (ypT0ypN0) to nCRT/CT in the patient’s cohort investigated. Further, a decrease in B lymphocyte (CD3+CD19+) count correlated with intermediate and impaired response while an elevated monocyte (CD14+CD33+) levels predicted a complete and intermediate (ypT1-4ypN0) response to nCRT/CT. On a tissue level, patients with a complete response displayed a decrease in the amount of infiltrating neutrophils as the immunoscore of CD15+ cells was significantly higher in patients’ biopsies compared to post-nCRT/CT surgical specimen, while in both, patients with complete and intermediate response an increase of natural killer (CD56+) cell density and GranzymeB expression was observed. Finally, no significant correlation was observed between peripheral blood and tissue immune marker expression.
To validate and expand these findings, a continuation of the analysis in an extended patient cohort is necessary. In addition, a detailed insight on the role of peripheral blood T cells and monocytes and their activation status is desirable. Further, in a follow-up trial, soluble activation markers/cytokines should be assayed, further distinguishing activated from resting or exhausted lymphocytes.
Cancer microenvironment is now recognized as a critical regulator of all stages of cancer development. Beside the tumor vasculature and tumor-infiltrating immune cells, other stromal cells such as cancer-associated fibroblasts (CAFs) regulate tumor growth. Fibroblasts are ubiquitous cells in connective tissue, where they shape the extracellular matrix (ECM). Fibroblasts are usually quiescent but get activated when tissue homeostasis is disturbed. Then, activated fibroblasts rebuild the ECM and communicate with local cells to participate in wound repair. These repair properties can go awry when being unchecked, which can lead to fibrosis and subsequently cancer development. CAFs can promote cancer development by fostering tumor cell growth, polarizing immune cells to an immunosuppressive phenotype, and crosslinking collagen to enable tumor cell invasion. Molecular mechanisms of CAF activation, thus, need to be understood to target these cells in tumors. Prostanoid prostaglandin E2 (PGE2) is viewed as a pro-tumor lipid mediator as suggested by studies pharmacologically or genetically targeting the enzymes producing PGE2, such as microsomal PGE synthase-1 (mPGES-1) in tumor models. Similar to CAFs, PGE2 drives tumor cell growth and tumor-associated immune suppression. Therefore, I hypothesized that PGE2 may play a role in CAF activation.
This hypothesis was tested in two mouse models of breast cancer (orthotopic grafting model, and polyoma middle T oncogene transgenic model), besides using isolated mammary gland (MG) fibroblasts in vitro. As expected, given the pro-tumor function of PGE2, knocking out mPGES-1 reduced the growth of oncogene-driven and transplanted mammary tumors. Surprisingly, CAF density was markedly increased when mPGES-1 was depleted. Importantly, despite reduced primary tumor growth, I observed enhanced lung metastasis upon mPGES-1depletion. Using MG-derived fibroblasts in vitro furthermore revealed that treatment with PGE2 reduced a TGFβtriggered CAF-like activation state. Importantly, bioinformatics analysis of a human breast cancer patient dataset revealed a negative correlation of a PGE2 production signature with fibroblast marker genes. In a next step I investigated if the increased CAF infiltrate was connected to the reduced tumor growth upon depletion of PGE2. To unravel this, I first asked through which E prostanoid (EP) receptor PGE2 signals in fibroblasts. MG fibroblasts mainly expressed EP3, and EP3 KO fibroblasts showed a hyper-proliferative and activated phenotype, indicating EP3 as the main PGE2 receptor in MG fibroblasts. Co-injecting of EP3 KO MG fibroblasts and tumor cells in WT mice suppressed tumor growth, whereas co-injection of WT fibroblasts with tumor cell in mPGES-1 KO mice increased tumor growth. These data indicate that PGE2 restricts CAF levels through EP3, which supports tumor growth. Whole transcriptome mRNAsequencing of WT and mPGES-1 KO FACS-sorted CAFs combined with immunohistochemical data suggested a role of p38 mitogen-activated protein kinase (MAPK) in the modulation of fibroblast activation by PGE2.
In summary, I showed in two breast cancer models that mPGES-1 depletion delays breast cancer progression, which is probably driven by the EP3-PGE2 signaling axis in host stroma. PGE2 appears to be a potent anti-fibroblast activation agent in tumors via EP3 and downstream p38 MAPK signaling. This study therefore hits the dogmatic perception of the general pro-tumor nature of PGE2; showing that PGE2 might be a double-edged mediator that can promote tumor growth at the primary site by restricting CAF expansion, which may in turn hinder infiltration of tumor cells to a secondary site.