Refine
Document Type
- Article (12)
Has Fulltext
- yes (12)
Is part of the Bibliography
- no (12)
Keywords
- invasion (4)
- MCAK (2)
- RITA (2)
- adipose-derived mesenchymal stem cells (2)
- focal adhesion (2)
- migration (2)
- motility (2)
- primary cilium (2)
- Anterior cingulate cortex (1)
- Aurora A (1)
Institute
- Medizin (12)
Hintergrund
In Anbetracht ihres bedeutenden Potenzials zur Verbesserung der medizinischen Versorgung wird Telemedizin weiterhin zu wenig genutzt. Trotz einiger erfolgreicher Pilotprojekte in den vergangenen Jahren ist insbesondere über die Hindernisse der Etablierung und Verstetigung von Telemedizin wenig bekannt. Diese Studie hatte das Ziel, die Einstellung niedergelassener Neurologen hinsichtlich der Nutzung von Telemedizin in der Epileptologie und resultierende Hinderungsgründe zu verstehen. Gleichzeitig werden mögliche Lösungsansätze präsentiert.
Methoden
Mithilfe eines individuell erstellten 14-Item-Fragebogens befragten wir prospektiv alle Neurologen, die zuvor die Teilnahme an einem transregionalen Telemedizinpilotprojekt im Bereich der Epileptologie abgelehnt oder keine Rückmeldung gegeben hatten, zu Gründen für und gegen den generellen Einsatz von bzw. die Teilnahme an Telemedizin.
Ergebnisse
Von 58 kontaktierten Neurologen antworteten 33 (57 %). Die häufigsten Gründe für die fehlende Nutzung der Telemedizin waren ein vermuteter Zeitmangel oder ein vermuteter zu großer organisatorischer Aufwand (49 %). Zudem wurden Bedenken bezüglich der technischen Ausstattung (30 %) und eine Präferenz für alternative Wege der intersektoralen Kommunikation (30 %) angegeben. Befürchtete Probleme in Bezug auf die Kostenerstattung für telemedizinische Leistungen waren für 27 % ein Hindernis. Neurologen in ländlichen Gebieten waren signifikant häufiger bereit, zunächst eine telemedizinische Konsultation anzufordern, bevor sie eine Überweisung ausstellen (p = 0,006).
Schlussfolgerungen
Die flächendeckende Etablierung von Telemedizinstrukturen ist immer noch durch Hindernisse erschwert, die meist im organisatorischen Bereich liegen. Die bestehenden Herausforderungen im Gesundheitswesen in ländlichen Gebieten sind eine besondere Chance für die Implementierung von Telemedizin. Die meisten Probleme der Telemedizin können gelöst werden, sollten aber bereits bei der Konzeptionierung von Projekten mitbedacht werden, um ihre Verstetigung zu erleichtern.
Polo-like kinase 1 regulates the stability of the mitotic centromere-associated kinesin in mitosis
(2014)
Proper bi-orientation of chromosomes is critical for the accurate segregation of chromosomes in mitosis. A key regulator of this process is MCAK, the mitotic centromere-associated kinesin. During mitosis the activity and localization of MCAK are regulated by mitotic key kinases including Plk1 and Aurora B. We show here that S621 in the MCAK’s C-terminal domain is the major phosphorylation site for Plk1. This phosphorylation regulates MCAK’s stability and facilitates its recognition by the ubiquitin/proteasome dependent APC/CCdc20 pathway leading to its D-box dependent degradation in mitosis. While phosphorylation of S621 does not directly affect its microtubule depolymerising activity, loss of Plk1 phosphorylation on S621 indirectly enhances its depolymerization activity in vivo by stabilizing MCAK, leading to an increased level of protein. Interfering with phosphorylation at S621 causes spindle formation defects and chromosome misalignments. Therefore, this study suggests a new mechanism by which Plk1 regulates MCAK: by regulating its degradation and hence controlling its turnover in mitosis.
RITA, the RBP‐J interacting and tubulin‐associated protein, has been reported to be related to tumor development, but the underlying mechanisms are not understood. Since RITA interacts with tubulin and coats microtubules of the cytoskeleton, we hypothesized that it is involved in cell motility. We show here that depletion of RITA reduces cell migration and invasion of diverse cancer cell lines and mouse embryonic fibroblasts. Cells depleted of RITA display stable focal adhesions (FA) with elevated active integrin, phosphorylated focal adhesion kinase, and paxillin. This is accompanied by enlarged size and disturbed turnover of FA. These cells also demonstrate increased polymerized tubulin. Interestingly, RITA is precipitated with the lipoma‐preferred partner (LPP), which is critical in actin cytoskeleton remodeling and cell migration. Suppression of RITA results in reduced LPP and α‐actinin at FA leading to compromised focal adhesion turnover and actin dynamics. This study identifies RITA as a novel crucial player in cell migration and invasion by affecting the turnover of FA through its interference with the dynamics of actin filaments and microtubules. Its deregulation may contribute to malignant progression.
Adipose-derived mesenchymal stem cells (ASCs) are considered to be a useful tool for regenerative medicine, owing to their capabilities in differentiation, self-renewal, and immunomodulation. These cells have become a focus in the clinical setting due to their abundance and easy isolation. However, ASCs from different depots are not well characterized. Here, we analyzed the functional similarities and differences of subcutaneous and visceral ASCs. Subcutaneous ASCs have an extraordinarily directed mode of motility and a highly dynamic focal adhesion turnover, even though they share similar surface markers, whereas visceral ASCs move in an undirected random pattern with more stable focal adhesions. Visceral ASCs have a higher potential to differentiate into adipogenic and osteogenic cells when compared to subcutaneous ASCs. In line with these observations, visceral ASCs demonstrate a more active sonic hedgehog pathway that is linked to a high expression of cilia/differentiation related genes. Moreover, visceral ASCs secrete higher levels of inflammatory cytokines interleukin-6, interleukin-8, and tumor necrosis factor α relative to subcutaneous ASCs. These findings highlight, that both ASC subpopulations share multiple cellular features, but significantly differ in their functions. The functional diversity of ASCs depends on their origin, cellular context and surrounding microenvironment within adipose tissues. The data provide important insight into the biology of ASCs, which might be useful in choosing the adequate ASC subpopulation for regenerative therapies.
Function of p21 (Cip1/Waf1/CDKN1A) in migration and invasion of cancer and trophoblastic cells
(2019)
Tumor progression and pregnancy have several features in common. Tumor cells and placental trophoblasts share many signaling pathways involved in migration and invasion. Preeclampsia, associated with impaired differentiation and migration of trophoblastic cells, is an unpredictable and unpreventable disease leading to maternal and perinatal mortality and morbidity. Like in tumor cells, most pathways, in which p21 is involved, are deregulated in trophoblasts of preeclamptic placentas. The aim of the present study was to enlighten p21’s role in tumorigenic choriocarcinoma and trophoblastic cell lines. We show that knockdown of p21 induces defects in chromosome movement during mitosis, though hardly affecting proliferation and cell cycle distribution. Moreover, suppression of p21 compromises the migration and invasion capability of various trophoblastic and cancer cell lines mediated by, at least partially, a reduction of the extracellular signal-regulated kinase 3, identified using transcriptome-wide profiling, real-time PCR, and Western blot. Further analyses show that downregulation of p21 is associated with reduced matrix metalloproteinase 2 and tissue inhibitor of metalloproteinases 2. This work evinces that p21 is involved in chromosome movement during mitosis as well as in the motility and invasion capacity of trophoblastic and cancer cell lines.
Adipose-derived mesenchymal stem cells (ASCs) have crucial functions, but their roles in obesity are not well defined. We show here that ASCs from obese individuals have defective primary cilia, which are shortened and unable to properly respond to stimuli. Impaired cilia compromise ASC functionalities. Exposure to obesity-related hypoxia and cytokines shortens cilia of lean ASCs. Like obese ASCs, lean ASCs treated with interleukin-6 are deficient in the Hedgehog pathway, and their differentiation capability is associated with increased ciliary disassembly genes like AURKA. Interestingly, inhibition of Aurora A or its downstream target the histone deacetylase 6 rescues the cilium length and function of obese ASCs. This work highlights a mechanism whereby defective cilia render ASCs dysfunctional, resulting in diseased adipose tissue. Impaired cilia in ASCs may be a key event in the pathogenesis of obesity, and its correction might provide an alternative strategy for combating obesity and its associated diseases.
The multifunctional protein p21Cip1/CDKN1A (p21) is an important and universal Cdk-interacting protein. Recently, we have reported that p21 is involved in the regulation of the mitotic kinase Cdk1/cyclin B1 and critical for successful mitosis and cytokinesis. In the present work we show that S130 of p21 is phosphorylated by Cdk1/cyclin B1 during mitosis, which reduces p21’s stability and binding affinity to Cdk1/cyclin B1. Interfering with this phosphorylation results in extended mitotic duration and defective chromosome segregation, indicating that this regulation ensures proper mitotic progression. Given that p53, the major transcriptional activator of p21, is the most frequently mutated gene in human cancer and that deregulated Cdk1 associates with the development of different types of cancer, this work provides new insight into the understanding of how deregulated p21 contributes to chromosomal instability and oncogenesis.
The microtubule (MT) cytoskeleton is crucial for cell motility and migration by regulating multiple cellular activities such as transport and endocytosis of key components of focal adhesions (FA). The kinesin-13 family is important in the regulation of MT dynamics and the best characterized member of this family is the mitotic centromere-associated kinesin (MCAK/KIF2C). Interestingly, its overexpression has been reported to be related to increased metastasis in various tumor entities. Moreover, MCAK is involved in the migration and invasion behavior of various cell types. However, the precise molecular mechanisms were not completely clarified. To address these issues, we generated CRISPR/dCas9 HeLa and retinal pigment epithelium (RPE) cell lines overexpressing or downregulating MCAK. Both up- or downregulation of MCAK led to reduced cell motility and poor migration in malignant as well as benign cells. Specifically, it’s up- or downregulation impaired FA protein composition and phosphorylation status, interfered with a proper spindle and chromosome segregation, disturbed the assembly and disassembly rate of FA, delayed cell adhesion, and compromised the plus-tip dynamics of MTs. In conclusion, our data suggest MCAK act as an important regulator for cell motility and migration by affecting the actin-MT cytoskeleton dynamics and the FA turnover, providing molecular mechanisms by which deregulated MCAK could promote malignant progression and metastasis of tumor cells.
Background: The development of the human placenta is tightly coordinated by a multitude of placental cell types, including human chorionic villi mesenchymal stromal cells (hCV-MSCs). Defective hCV-MSCs have been reported in preeclampsia (PE), a gestational hypertensive disease characterized by maternal endothelial dysfunction and systemic inflammation. Our goal was to determine whether hCV-MSCs are ciliated and whether altered ciliation is responsible for defective hCV-MSCs in preeclamptic placentas, as the primary cilium is a hub for signal transduction, which is important for various cellular activities.
Methods: In the present work, we collected placental tissues from different gestational stages and we isolated hCV-MSCs from 1st trimester, term control, and preeclamptic placentas. We studied their ciliation, functionality, and impact on trophoblastic cell lines and organoids formed from human trophoblast stem cells (hTSCs) and from the trophoblastic cell line JEG-3 with various cellular and molecular methods, including immunofluorescence staining, gene analysis, spheroid/organoid formation, motility, and cellular network formation assay. The statistical evaluation was performed using a Student’s t test (two-tailed and paired or homoscedastic) or an unpaired Mann–Whitney U test (two-tailed).
Results: The results show that primary cilia appeared abundantly in normal hCV-MSCs, especially in the early development of the placenta. Compared to control hCV-MSCs, the primary cilia were truncated, and there were fewer ciliated hCV-MSCs derived from preeclamptic placentas with impaired hedgehog signaling. Primary cilia are necessary for hCV-MSCs’ proper signal transduction, motility, homing, and differentiation, which are impaired in preeclamptic hCV-MSCs. Moreover, hCV-MSCs derived from preeclamptic placentas are significantly less capable of promoting growth and differentiation of placental organoids, as well as cellular network formation.
Conclusions: These data suggest that the primary cilium is required for the functionality of hCV-MSCs and primary cilia are impaired in hCV-MSCs from preeclamptic placentas.
Human placentation is a highly invasive process. Deficiency in the invasiveness of trophoblasts is associated with a spectrum of gestational diseases, such as preeclampsia (PE). The oncogene B-cell lymphoma 6 (BCL6) is involved in the migration and invasion of various malignant cells. Intriguingly, its expression is deregulated in preeclamptic placentas. We have reported that BCL6 is required for the proliferation, survival, fusion, and syncytialization of trophoblasts. In the present work, we show that the inhibition of BCL6, either by its gene silencing or by using specific small molecule inhibitors, impairs the migration and invasion of trophoblastic cells, by reducing cell adhesion and compromising the dynamics of the actin cytoskeleton. Moreover, the suppression of BCL6 weakens the signals of the phosphorylated focal adhesion kinase, Akt/protein kinase B, and extracellular regulated kinase 1/2, accompanied by more stationary, but less migratory, cells. Interestingly, transcriptomic analyses reveal that a small interfering RNA-induced reduction of BCL6 decreases the levels of numerous genes, such as p21 activated kinase 1, myosin light chain kinase, and gamma actin related to cell adhesion, actin dynamics, and cell migration. These data suggest BCL6 as a crucial player in the migration and invasion of trophoblasts in the early stages of placental development through the regulation of various genes associated with the migratory machinery.
