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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.
Role of Orphan G-protein-coupled receptor GPRC5B in smooth muscle contractility and differentiation
(2019)
G protein coupled receptors (GPCRs) are the largest family of cell-surface receptors encoded in the human genome. They mediate the cellular responses to a wide variety of stimuli, ranging from light, odorants, and metabolic cues to hormones, neurotransmitters, and local mediators. Upon ligand binding, the GPCR undergoes conformational changes resulting in the activation of heterotrimeric G-proteins belonging to the families Gs, Gi/o, Gq/11, G12/13, which in turn mediate the downstream signaling. While most of the 360 non-olfactory GPCRs are well studied, approximately 120 GPCRs are still considered "orphan", meaning that their mechanism of activation and biological function is unknown. GPCRs have been functionally described in the regulation of almost all organ systems, and their dysregulation has been implicated in the pathogenesis of a multitude of diseases. In the vascular system, the contractile tone of vessels is crucially regulated by GPCRs. Substances that act through G12/13- and Gq/11-coupled GPCRs are associated with facilitation of contraction, while Gs-coupled GPCRs are usually associated with the induction of relaxation. Furthermore, while Gq/11 pathway activation promotes proliferation and dedifferentiation of vascular smooth muscle cells (VSMC), G12/13 and Gs signaling pathways promote expression of contractile proteins and differentiation.
The functional properties of VSMC depend on the anatomical location, and a recent single-cell expression analysis showed that VSMC from different vascular beds have different patterns of GPCR expression. Interestingly, smooth muscle cells (SMCs) from resistance arteries not only express various GPCRs for known modulators of vascular tone, but also a number of orphan GPCRs. These results suggest a potential role of orphan GPCRs in the modulation of blood pressure. Orphan GPCR GPRC5B was one of the GPCRs enriched in resistance arteries, and this receptor was also upregulated in dedifferentiated aortal SMC. The function of GPRC5B in these types of SMC is currently unknown. In vitro studies suggested that GPRC5B negatively regulates obesity, inflammation, insulin secretion and fibrotic activity, but there are no data available with respect to its function in regulation of vascular tone or other SMC functions.
Our study aimed at the identification of the specific functions of GPRC5B in SMC. To do so, we generated a SMC-specific GPRC5B-deficient mouse line by crossing Gprc5bfl/fl mice with smooth muscle-specific, tamoxifen-inducible Myh11-CreERT2 mice. We found that SMC-specific deletion of GPRC5B did neither affect myogenic tone in pressure myography, nor the response to the contractile agonists in wire myography. In contrast, vessel relaxation in response to prostacyclin analogues cicaprost and iloprost, which act on the prostacyclin receptor IP, were increased. These results suggested a selective improvement of IP receptor signaling. The IP receptor is coupled to Gs protein, it promotes vasorelaxation and acts as a restraint on platelet activation. Using overexpression of IP and GPRC5B in HEK cells, we found that GPRC5B physically interacts with the IP receptor and controls IP trafficking and membrane localization. Furthermore, we found that membrane IP receptor expression was increased in GPRC5B-deficient human aortic SMC and in resistance vessels of SMC-specific GPRC5B. To investigate the importance of increased IP-mediated signaling in SMC in vivo, we measured blood pressure in two mouse models of hypertension. We found that SMC-deletion of Gprc5b resulted in a significant reduction of blood pressure compared with control mice, which suggested that Gprc5b negatively regulated relaxation in hypertensive disease by decreasing IP mediated relaxation. In line with this notion we found that application of the IP antagonist Cay10441 largely abrogated the beneficial effect of GPRC5B inactivation in this hypertension model. Another important function of the IP receptor is the regulation of SMC differentiation, which led us to investigate the differentiation state of GPRC5B-deficient SMC. We found that deletion of GPRC5B enhanced expression of contractile genes and reduced expression of proliferative markers. This improved differentiation was, at least partially, due to increased IP signaling in SMC. Moreover, in a mouse model of atherosclerosis SMC-specific deletion of Gprc5b reduced plaque area and contributed to a more stable fibrous cap by promoting differentiation.
In conclusion, deletion of GPRC5B in SMC significantly improved contractility and differentiation by increasing IP receptor membrane availability and signaling.
Langzeitbeobachtung der Therapie von Hämophilie A-Patienten mit einem humanen Faktor VIII-Konzentrat
(2019)
This doctoral thesis entitled “Long-term surveillance of the therapy of haemophilia A patients with a human plasma-derived factor VIII concentrate” was performed to assess the influence of the chronic long-term therapy with a human plasma-derived factor VIII concentrate in daily clinical practice on the health of haemophilia A patients.
Haemophilia A is a chronic disease, caused by a congenital deficiency of coagulation factor VIII, which requires life-long haemostatic treatment. The severity of bleedings, as the main clinical feature of haemophilia A, is generally correlated with the residual activity of coagulation factor VIII.
Until recently, factor VIII preparations, used to replace the deficient factor VIII, were the only treatment option for haemophilia A. Development of inhibitory antibodies against factor VIII is the most serious complication associated with the use of factor VIII products, rendering the administered factor VIII ineffective.
To date, all novel treatments still rely on some factor VIII replacement therapy. At least in the near future and probably for longer, (concomitant) therapy with factor VIII concentrates will continue to be necessary for treatment of haemophilia A, emphasising the continuous need for efficacy and safety data in terms of pharmacovigilance on factor VIII replacement therapy.
Medicines to treat haemophilia A, are authorised for use, when evidence of its efficacy and safety is limited to data of a small number of investigated patients during short-term observation periods of about six months, and thus have not been systematically assessed in all patient groups until marketing authorisation. Long-term efficacy and safety data from post-marketing surveillance are important to prove that a chronic treatment is efficacious and safe in the real-life setting by monitoring “real-life” patients of all age groups, rather than a carefully selected patient population. Medical and scientific analyses of such long-term data are crucial to detect, understand, and potentially prevent the harm resulting from (new) adverse drug reactions, including those, which only rarely occur and therefore are difficult to detect.
Therefore, data from two prospective surveillance studies investigating real-life therapies with the same human plasma derived factor VIII concentrate were combined and analysed retrospectively. It was hypothesised that the chronic long term therapy with a human plasma-derived factor VIII concentrate in daily clinical practice is effective, safe, and well tolerated with no unexpected adverse effect on the health of haemophilia A patients. It was the aim of this analysis to investigate the influence of the chronic long-term treatment with the factor VIII concentrate on the health of patients with severe as well as nonsevere haemophilia A including all age groups in a real-life setting. In addition, the influence of prophylactic factor VIII treatment or the switch to this regimen on the annual bleeding rate of all haemophilia A patients, and the long-term effects of this regimen on the patients’ annual bleeding rates were investigated.
Starting in 1998 until 2015, data of 1418 patient-years from 198 haemophilia A patients representing all age groups and haemophilia A severities were analysed. This study covered 18 years of documentation time with a mean observation period of more than seven years per patient. It is the longest study of a single factor VIII concentrate conducted so far, investigating the therapy of haemophilia A. The only observed side effects involved low incident factor VIII inhibitor formation in patients at risk (13 % of previously untreated patients, compared with usually about 30 %). Factor VIII inhibitor development was mainly transient, with low titers, and without clinical relevance. Any, even low frequent prophylaxis was found to be significantly better than on demand and had the greatest effect on the annual bleeding rate of patients, irrespective of their age or haemophilia A severity. Patients suffered during continuous prophylaxis from a very low bleeding rate (median 1.3 compared with 31.4 under on demand), down to no bleeding per year. Patients whose regimen changed to continuous prophylaxis benefitted most (median annual bleeding rate 1.1), irrespective of age or haemophilia A severity.
This analysis demonstrates that the chronic long-term therapy with the plasma-derived factor VIII concentrate in daily clinical practice is effective, safe, and well tolerated. Thus, data on efficacy and safety obtained during chronic long-term therapy with the human plasma-derived factor VIII concentrate reaffirm that there is no unexpected adverse effect on the health of haemophilia A patients.
These results support the therapeutic concept of a life-long prophylaxis of haemophilia A patients with a human plasma-derived factor VIII concentrate.
Characterization of SPRTN, the first mammalian metalloprotease that repairs DNA-protein-crosslinks
(2019)
DNA is constantly exposed to various endogenous and exogenous sources causing different kinds of DNA damage. To overcome this threat, cells have evolved various repair mechanisms. Impairments of these repair mechanisms result in diverse diseases. Ruijs-Aalfs syndrome is a monogenic disease characterized by accelerated ageing and carcinogenesis, typical features of impaired DNA repair and was shown to be caused by germline mutations of SPRTN, a newly identified and only partially understood protein. A role of SPRTN in DNA damage response was previously shown and an involvement in translesion synthesis (TLS) proposed. However, later discoveries revealed an essential function of SPRTN, being indispensible for embryonic development of vertebrates and cellular survival, whereby this function is independent of SPRTN’s proposed function in TLS. The essential function of SPRTN was proposed to be contained in its protease domain but remained unclear.
In this study we identify SPRTN as the first mammalian metalloprotease that repairs DNA-protein-crosslinks (DPCs). DPCs represent a specific type of DNA-lesions with bulky protein adducts covalently linked to DNA thereby being highly toxic as they potentially stall replication forks and lead to double strand breaks and genomic instability. DPC-repair remains only partially understood despite their frequent appearance and toxicity. With this study we discover and characterize a new mechanism of DPC-repair in mammalian cells - a proteolytic cleavage of the protein adduct by the metalloprotease SPRTN. Accordingly, a proteolytic activity of SPRTN is demonstrated and s SPRTN-recruitment to DNA upon DPC-induction displayed. Furthermore, SPRTN exhibits degradation of different proteins covalently bound to DNA in form of DPCs, but not of unbound fractions of the same protein substrates. Consequently, mutations of SPRTN’s proteolytic core as well as a mislocalization or depletion of SPRTN result in impaired DPC-repair. The importance of SPRTN-mediated DPC-removal is confirmed by a severely compromised response to DPC-inducing agents for cells with impaired SPRTN function. Additionally to the discovery of SPRTN’s essential function this study further provides an explanation of the molecular mechanism underlying Ruijs-Aalfs syndrome (RJALS), the segmental progeroid syndrome resulting from SPRTN mutation. The effects of the identified clinical mutations on the DPC-repair function of SPRTN are explained and a DPC-accumulation in cells carrying clinical SPRTN-mutation displayed. The obtained data provides sufficient evidence that an impaired DPC-repair is the pathophysiologic cause of RJALS-syndrome, confirming the importance of SPRTN’s newly identified function. In conclusion, SPRTN is the first identified mammalian metalloprotease with a DPC-repairing function and the impairment of SPRTN-mediated DPC-removal is the underlying mechanism of RJALS syndrome.
Durch Implementierung eines effizienten Früherkennungsprogramms ist die Inzidenz des Zervixkarzinoms in Industrienationen seit 2005 auf konstant niedrigem Niveau. Ungeachtet dessen ist das Zervixkarzinom mit deutlich höheren Inzidenzraten und weniger als 50% Gesamtüberleben in den nicht industrialisierten Staaten die vierthäufigste Tumorentität der Frau weltweit.
Zur Behandlung des lokal fortgeschrittenen Zervixkarzinoms (FIGO Stadium IIb bis IVa bzw. Ib2/IIa2 mit mehreren histologischen Risikofaktoren) besteht nach aktueller Leitlinie (Stand 2014) und internationalem Konsens Indikation zur platinhaltigen Radiochemotherapie (RCT), subsequent gefolgt von einer (High Dose-Rate) Brachytherapie (HDR-BT). Unter diesen Umständen beträgt die lokale Kontrolle für Patientinnen mit lokal fortgeschrittenem Tumor zwischen 74% und 85%.
Dennoch stagnieren Gesamtüberleben und das spezifische Überleben bezogen auf verschiedene klinische Endpunkte, sodass die Entwicklung neuer Behandlungsstrategien und Therapieoptionen, insbesondere zur Behandlung rezidivierter und metastasierter Erkrankungsstadien, angezeigt ist. Darüber hinaus spielen im Gegensatz zu anderen Tumorentitäten molekulare Marker sowohl als prädiktive als auch als therapeutische Targets bei der Behandlung des Zervixkarzinoms eine bislang untergeordnete Rolle, während molekular-zielgerichtete Therapien in der modernen Krebstherapie einen immer größeren Stellenwert einnehmen.
Ziel der hier vorliegenden Arbeit ist es, neue Biomarker für das Zervixkarzinom und dessen Ansprechen auf simultane Radiochemotherapie und anschließende Brachytherapie zu identifizieren.
Zu diesem Zweck untersuchten wir in einem Patientenkollektiv von 74 Patientinnen mit histologisch gesichertem Zervixkarzinom (FIGO Ib - IVb) prätherapeutisch gewonnenes Biopsiegewebe. Mittels immunhistochemischer Methoden wurde die Expression von Polo-like Kinase 3 (PLK3) und phosphoT273 Caspase-8 erfasst und quantifiziert. Die Ergebnisse wurden anschließend mit klinischen bzw. histo-pathologischen Charakteristika, einschließlich der p16INK4a Expression und den klinischen Endpunkten lokales progressionsfreies- und Fernmetastasen-freies
Überleben bzw. dem tumorspezifischem und dem Gesamtüberleben nach kurativ intendierter Therapie korreliert.
Hierbei konnte zunächst eine signifikante Korrelation zwischen der PLK3 und pT273 Caspase-8 Expression beobachtet werden (p = 0.009). Darüber hinaus war PLK3 signifikant mit dem N-Status (p = 0.046), dem M-Status (0.026) und dem FIGO-Stadium (p = 0.001) assoziiert, wohingegen die pT273 Caspase8-Expression signifikant mit der Tumorgröße (T-Stadium) korreliert war. Bezogen auf univariate Überlebenszeitanalysen war eine erhöhte PLK3-Expression signifikant mit einer geringeren Rate an Fernmetastasen (DMFS p = 0.009) sowie einem signifikant verlängertem tumorspezifischen und Gesamtüberleben assoziiert (CSS p = 0.001, OS p = 0.003). Vergleichbare Ergebnisse konnten auch für die pT273-Caspase 8 Expression mit einer verringerten Metastasierungsrate (p=0.021) und verbessertem tumorspezifischem (p<0,001) sowie Gesamtüberleben (p=<0.001) gezeigt werden. In den multivariaten Analysen verblieb die pT273-Caspase 8-Expression mit einem signifikant verbesserten Gesamtüberleben (p=0.001).
Zusammenfassend belegen diese Daten erstmals eine signifikante Korrelation zwischen einer erhöhten prä-therapeutischen PLK3 und pT273 Caspase 8- Expression und einem zu favorisierenden klinischen Verlauf nach mit Radiochemotherapie behandeltem Zervixkarzinom.
Acute and chronic inflammation play a pivotal role in various diseases, such as rheumatoid arthritis, atherosclerosis, bacterial as well as viral infections and therefore are an everyday-challenge in clinical practice. In this context, biologically active products of the cyclooxygenases and the prostanoid synthases, e.g. prostaglandins, critically contribute to various aspects of the inflammatory response in almost every tissue of the body. Emerging evidence over the past decades has demonstrated that these mediators are not only responsible for a pro-inflammatory response, but also show anti-inflammatory and pro-resolving properties. The relevance of biologically active lipids in this context is strengthened by the clinical efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs), e.g. Aspirin®, which block the biosynthesis of the mediators via the cyclooxygenase (COX) enzymes. Notably, microsomal prostaglandin E synthase-1 (mPGES-1)-derived prostaglandin E2 (PGE2) is a well-studied, functionally versatile PG, which promotes its effects via specific G protein-coupled receptors (GPCRs). Activation of these receptors elicits an internal signal transduction cascade, including activation of the adenylyl cyclase (AC). Active AC contributes to an elevated intracellular cyclic adenosine monophosphate (cAMP) level, which in turn activates the transcription factor cAMP response element-binding protein (CREB) via phosphorylation.
While the role of PGE2 in the inflammatory context has been well-documented in previous literature, relatively little is known about CREB-dependent transcriptional changes in inflammation. Therefore, the aim of this study was to investigate the effect of mPGES-1-derived PGE2 on CREB-mediated transcriptional changes specifically in murine wild-type (WT) and mPGES-1 knock-out (KO) macrophages in an inflammatory context. To address this issue, bone marrow-derived macrophages (BMDMs) were treated with either the bacterial cell wall component lipopolysaccharide (LPS) in combination with interferon-γ (IFN-γ) or the yeast extract zymosan. To analyze effects on CREB activation we determined protein expression profiles of relevant PGE2-synthesizing enzymes, i.e. COX-2 and mPGES-1, as well as activity of the downstream transcription factor CREB. The activity of mPGES-1 was simultaneously determined by the analysis of the prostanoid kinetics. Under these experimental conditions we showed that COX-2 is strongly induced, and we also observed elevated activated CREB levels in WT as well as in mPGES-1 KO macrophages. Further, both LPS+IFN-γ and zymosan increased expression of mPGES-1 in WT but not in mPGES-1-deficient macrophages. These findings go in hand with largely similar alterations in the PGD2, TXB2, PGF2α profiles in WT and mPGES-1 KO macrophages upon stimulation. Of note, an elevated PGE2 production was also observed in mPGES-1-deficient macrophages at later stages upon inflammatory conditions. Subsequently, potential CREB-regulated targets were identified in macrophages upon inflammatory stimuli after 16 h by chromatin immunoprecipitation (ChIP) followed by Next-Generation-Sequencing (NGS). Surprisingly, despite equal levels of pCREB the characterization of CREB binding sites revealed different targetome profiles between WT and mPGES-1 KO macrophages. Specifically, the fatty acid metabolic processes-associated targets appeared to be selectively lost in mPGES-1-deficient vs. WT macrophages. We further validated one of those targets, i.e. the endoplasmic reticulum lipid raft-associated protein 1 (Erlin1), at the mRNA expression level, which indeed was differentially transcribed in response to different PGE2 synthesizing conditions.
Mechanistically, CREB is a well-characterized phosphorylation-dependent transcription factor in cell survival, proliferation, differentiation, and immune responses. Yet, our understanding of the functions of CREB in inflammation, specifically with respect to its activation by PGE2, is insufficient. Due to its biological relevance in inflammation it clearly requires additional studies to shed light on the details of CREB activation in macrophages to provide possibilities of therapeutic interventions.
The carpal tunnel syndrome (CTS) is a chronic compression of the median nerve in the carpal tunnel, a condition in which the nerve is constricted especially under the flexor retinaculum (FR). The disease predominantly appears between 40 and 83 years of age. Women are significantly more often affected than men. The same applies to overweight people in comparison to normal weight people. Abnormal sensations at night, including paresthesias and dysesthesias, are classical CTS symptoms, predominately involving the middle fingers, later also the thumb. Diagnosis of CTS usually proceeds by motor nerve conduction study (mNCS) and determination of the distal motoric latency (DML). In conformity with electrophysiology, peripheral nerve ultrasonography has also attained an important diagnostic informative value. In principle, there is an open surgical procedure and an endoscopic carpal roof cleavage. The goal of therapy is the complete open division of the flexor retinaculum (FR) in order to relieve the median nerve from compression.
This work examines the morphological alterations of the median nerve at the site of the carpal tunnel after surgical decompression by means of high-resolution neurosonography in the scope of a prospective study. More than 100 patients were examined between October and December 2014 for planned decompressions surgery due to CTS. A total of 81 patients were prospectively included, 5 of which could not take part in the follow-up after six months and were excluded from this evaluation. A medical CTS case history, clinical examination findings, as well as a neurographic result were included. Patients with a relapse operation were not considered in this regard. Apart from a clinical examination and questioning of the patient three and six months after surgery, an electrophysiological examination and a high-resolution sonography of the median nerve were also carried out. Electroneurography and nerve sonography of the median nerve were applied to both hands. A prolonged distal motor latency of the median nerve amounting to 4ms, as well as a slowed nerve conduction velocity below the benchmark value of approx. 45m/s, were classified as pathological findings. In sonography, the largest cross-section area (CSA) of the median nerve was measured by applying transversal slicing to the distal transverse creases of the skin on the palmar surface of the wrist (rasceta) as well as 5cm proximal to the rasceta. The highest CSA values were determined visually. In cases of doubt several transversal slices were made until the highest CSA value could be identified.
The average age at which the disease was contracted amounted to 56.9 years. With one exception, all patients complained of nocturnal brachialgia before surgery (74, 96.2%). As far as neurological symptoms were concerned, 72 patients had paresthesias (93.6%) and 29 patients (37.7%) felt permanent numbness. A thenar atrophy of higher degree was diagnosed in two patients (2.6%). These complaints had improved in the patients surveyed in the scope of postoperative evaluations after three and six months.
Patients with motor deficits had a statistically significantly longer preoperative distal motor latency (10.5 ± 2.8ms vs. 6.5 ± 2.3ms). We observed an improvement of distal motor latency in 98% of the patients three months and six months after surgical decompression, displaying a statistically significant DML decrease from 6.6 ± 2.4ms to 4.8 ± 1.0ms and from 6.6 ± 2.4ms to 4.4 ± 1.0ms, respectively. There was a statistically significant correlation between the decrease of the nerve cross-section area and the decrease of distal motor latency.
At the time of the follow-up examination, three months after surgery, we were able to document a decrease in the CSA value in 80% of the patients. The mean CSA value decreased from 14.7 ± 4.4mm² to 12.4 ± 3.4 mm². Six months after surgical decompression the mean CSA value decreased from 14.3 ± 4.4mm² to 9.6 ± 2.3mm². Patients with a preoperative CSA value of ≥ 12mm² displayed a significantly greater relative reduction of their postoperative CSA value. Concerning all preoperative and postoperative parameters in patients who had undergone either open or endoscopic surgery, none revealed significant differences. Neither could an exploratory analysis (i.e. age, diabetic diseases) reveal any significant correlation between the parameters. Prior to surgery, a flattening of the median nerve or a loss of its fascicular structure (texture) had also been seen to exist in patients, apart from the nerve's larger cross-section area. Nerve sonography is an inexpensive and fast method. It is also extraordinarily reliable in the assessment of the CTS diagnosis and suits the necessary demands. We achieved a good efficiency with our sonographic examinations in the study presented here. New and improved developments show that high-resolution sonography will gain more and more significance in future CTS diagnostics.
The ubiquitin-related SUMO system represents a versatile post-translational modification pathway controlling a variety of cellular signalling networks. In mammalian cells, lysine residues of target proteins can be covalently modified with three SUMO isoforms (SUMO1, SUMO2 and SUMO3) resulting in conjugation of either single SUMO moieties or formation of poly-SUMO chains. Importantly, SUMO modification is a reversible process, where the deconjugation of SUMO from its substrates is mediated by SUMO proteases. In humans, the best-characterized subfamily is the SENP family of SUMO-specific isopeptidases comprised of SENP1-3 and SENP5-7. For undisturbed cellular signalling events, a proper balance of SUMO conjugation and deconjugation is crucial. SENPs fulfil the important function of counteracting SUMOylation. A key question is how the relatively low number of SENPs specifically controls the SUMOylation status of hundreds of cellular proteins.
The aim of this thesis was to uncover the regulation and substrate specificity of distinct SUMO isopeptidases in order to better understand their role in cellular signalling pathways.
In the first part of this work, we investigated the influence of hypoxia on SUMO signalling, in particular on the activity of SENPs. Importantly, we found that the catalytic activity of distinct SENPs (especially SENP1 and SENP3) is strongly but reversibly diminished under low oxygen. As a consequence, the SUMO modification of a specific subset of proteins is changed under hypoxia. We specifically identified proteins being hyperSUMOylated after 24 hours of hypoxia by SUMO1 immunoprecipitation followed by mass spectrometry. We further validated the transcriptional co-repressor BHLHE40 as hypoxic SUMO target and confirmed SENP1 as responsible isopeptidase for deconjugation of SUMOylated BHLHE40. We provide evidence that SUMO conjugation to BHLHE40 enhances its repressive functions on the expression of the metabolic master regulator PGC-1α. Therefore we propose a model where inactivation of SENP1 under hypoxia results in SUMOylated BHLHE40, possibly contributing to metabolic reprogramming under hypoxia.
To get insight into substrate selectivity of SENP family members, in particular SENP3 and SENP6, we choose a proteomic profiling strategy. For the identification of specific SUMO substrates controlled by SENP3, we applied a large-scale IP-MS approach in SENP3 KO and WT cells. The most strongly induced SUMO targets in the absence of SENP3 were key regulators of ribosome maturation. We identified factors involved in the remodelling of both 90S and 60S pre-ribosomes. SENP3 has already been described as being critically involved in maturation of the pre-60S subunit and 28S rRNA processing. Previously described SENP3-regulated master targets in this process are the ribosome maturation factors PELP1 and Las1L. Importantly, both were also identified as the most significantly regulated SENP3 targets in our unbiased proteomic approach. Importantly, however, enhanced SUMOylation was also detected on 90S-associated regulators, such as BMS1. Altogether, these data strengthen the functional link between SENP3 and ribosome biogenesis and point to a role of SENP3 beyond 60S maturation.
In addition to SENP3, we explored the substrate specificity of SENP6, which mainly acts on polymeric SUMO2/3 chains. Applying a proteomic profiling strategy, we were able to identify SENP6-controlled SUMO networks functioning in DNA damage response as well as chromatin organization. We demonstrated that SENP6 reverses polySUMOylation of several subunits of the cohesin complex, thereby regulating the SUMOylation status and chromatin association of this complex. Furthermore, we found a tight interaction of SENP6 with the hPSO4/PRP19 complex, involved in DNA damage response by activation of the ATR-CHK1 signalling cascade. In cells depleted of SENP6, we observe deficient recruitment of the co-activator ATRIP to chromatin which results in diminished CHK1 activation. We therefore illustrate a general role of SENP6 in the control of chromatin-associated protein networks involved in genome integrity and chromatin organization.
Malaria is an environmental disease, influenced not only by physical and biological environmental factors but also by socio-cultural ones. These factors affect each other, and, in turn, cause the disease in endemic areas. Some factors that cause the high morbidity rate associated with the disease include climate change, physical environment that varies geographically, socio-economic circumstances, and human behaviour in the affected areas. Other risk factors include housing conditions and poor sanitation, lack of hygiene practices, and inadequate health services in endemic areas. Efforts to eliminate malaria have been a topic at various public health meetings for decades. However, in Indonesia, malaria continues to be one of the leading causes of morbidity and mortality. The research aimed to analyse and model the critical variables associated with malaria in endemic areas of Indonesia. So, this included relationships between malaria and both socio-demographic variables and physical environments. The research is in three parts, adding value to a model that determines malaria in Indonesia.
This dissertation follows a cross-sectional design survey. The research data in this PhD dissertation is drawn from four sources: routine reporting of malaria from provincial health departments in South Sumatra; the national basic health research data (IDN acronym: Riskesdas); climate data from the Meteorology, Climatology, and Geophysics Climatological Agency (IDN acronym: BMKG); spatial data from Geospatial Information Agency (IDN acronym: BIG). This study takes a holistic approach, integrating the following univariate, bivariate, and multivariable logistic regressions, to establish a modelling determinant of malaria. Additionally, the researchers compared the performance of both Geographically Weighted Regression (GWR) and Ordinary Least Square (OLS). It also used some statistical analysis software tools for data processing, analysis, visualisation, and the development of the model as follows: Statistical Package for the Social Sciences (SPSS), Stata, Aeronautical Reconnaissance Coverage Geographic Information System (ArcGIS) 10.3, and GWR 4.0 version 4.0.90 for Windows.
The prevalence of malaria varied according to the local area, which, in turn, was related to the local physical environment that varied geographically. The determinants for malaria cases varied locally and regionally as well. Rural areas with a high percentage of households keeping livestock/pets showed a higher proportion of malaria prevalence than the national average. Other socio-demographic risk factors included gender, age, occupation, knowledge about healthcare, protection against mosquito bites, and condition of dwellings. This study reveals that the independent variables - "rainfall", "altitude", and "distance from mosquito resting sites in the forest," in global OLS analysis- are significantly associated with malaria cases in South Sumatra, Indonesia.
On the other hand, in the GWR analysis, the determinants of malaria cases at the village level vary geographically. Therefore, it is essential for the decision maker, the government, to acquire a more in-depth understanding of region-specific, ecological factors that influence confirmed malaria cases. The findings lead to the recommendation for developing sustainable regional malaria control programs and incentivising malaria elimination efforts, particularly at the village level. In another setting, the research led to the conclusion that the presence of mid-sized livestock comprised a significant risk factor for contracting malaria in rural Indonesia. The recommendation, especially for the study area, is to employ integrated vector management (IVM), for example, the simultaneous implementation of insecticide-treated bed nets (ITNs) and insecticide-treated livestock (ITL). Other factors such as socio-demographic and use of health care facilities were also crucial as they related to malaria prevalence. Further, the research leads to the recommendation for increased education and increased promotion and utilisation of the health care framework to promote knowledge and awareness of villagers on how to protect themselves from Anopheles bites. Finally, improving information concerning the availability of health care services and access to various health facilities in endemic areas is essential.