Junctional ER Organization Affects Mechanotransduction at Cadherin-Mediated Adhesions.

Cadherin-mediated adhesions (also known as adherens junctions) are adhesive complexes that connect neighboring cells in a tissue. While the role of the actin cytoskeleton in withstanding tension at these sites of contact is well documented, little is known about the involvement of microtubules and the associated endoplasmic reticulum (ER) network in cadherin mechanotransduction. Therefore, we investigated how the organization of ER extensions in close proximity of cadherin-mediated adhesions can affect such complexes, and vice versa. Here, we show that the extension of the ER to cadherin-mediated adhesions is tension dependent and appears to be cadherin-type specific. Furthermore, the different structural organization of the ER/microtubule network seems to affect the localization of ER-bound PTP1B at cadherin-mediated adhesions. This phosphatase is involved in the modulation of vinculin, a molecular clutch which enables differential engagement of the cadherin-catenin layer with the actomyosin cytoskeleton in response to tension. This suggests a link between structural organization of the ER/microtubule network around cadherin-specific adhesions, to control the mechanotransduction of adherens junctions by modulation of vinculin conformational state.

Lonomia obliqua bristle extract modulates Rac1 activation, membrane dynamics and cell adhesion properties.

Lonomia obliqua is a caterpillar of potential therapeutic interest whose venom is able to induce severe blood leakage and modulate leukocyte migration. Since both phenotypes are associated with changes in cytoskeleton dynamics and cell adhesion properties, the aim of this study was to analyze the effects of Lonomia obliqua bristle extract (LOBE) in cell adhesion and migration signaling. Proteomic analysis revealed that epithelial cells (CHO-K1) exposed to LOBE (30 µg/mL, 30 min) exhibited changes in levels of actin regulatory proteins, including RhoGTPases. These changes correlated with an increase in the activity of the RhoGTPase family member Rac as measured by Förster resonance energy transfer (FRET). When plated in migration promoting conditions, CHO-K1 cells exposed to LOBE (10 µg/mL) showed an increase in membrane ruffling after short (30 min) period of incubation that was accompanied by changes in the distribution of the adhesion markers paxillin, vinculin and an increase of focal adhesion kinase autophosphorylation levels (Y397), suggesting changes in cell-extracellular matrix (ECM) adhesion properties and signaling. These data suggest that LOBE possesses bioactive molecules that are capable to modulated cell migration signaling, cytoskeletal dynamics and cell-ECM properties of several cell types.

Focal adhesion proteins, vinculin and integrin ß5, during early pregnancy in rat uterine epithelial cells: anastrozole favors their normal distribution / Proteínas de adhesión focales, vinculina e integrina ß5, durante el embarazo temprano en células epiteliales uterinas de rata: anastrozol favorece su distribución normal

SUMMARY: An alternative superovulator to replace clomiphene citrate is needed as clomiphene citrate is associated with low pregnancy rates. Anastrozole is an effective superovulator, but it has not been well researched. In order to determine the effectiveness of anastrozole as a superovulator and to compare it with clomiphene citrate in similar situations, this study ascertained the effects of these drugs on the expression of the focal adhesion proteins, vinculin and integrin β5, which are uterine receptivity markers, in the uterine epithelial cells of day 1 and day 6 pregnant Wistar rats. The results show that vinculin and integrin β5 are co-localized at the base of the uterine epithelium at day 1 of pregnancy whereas at day 6, they disassemble from the basal focal adhesions and co-localize and significantly increase their expression apically (p≤0.0001). Moreover, there is a significant difference in the protein expression levels of vinculin and integrin b5 in uterine luminal epithelial cells between untreated (control) and chlomiphene citrate treated rats (p≤0.0001), anastrozole and chlomiphene citrate treated rats at day 6 (p≤0.0001) suggesting the interpretation that anastrozole seems to enhance their expression in order to perhaps assist in the implantation process of the blastocyst. The immunofluorescence experiments agree with the vinculin and integrin β5 gene expression findings in which at day 6 of pregnancy, vinculin and integrin β5 gene expression are significantly upregulated in uterine luminal epithelial cells in the anastrozole treated group relative to the calibrator sample (p≤0.0001). These findings suggest that anastrozole is implantation friendly.

RESUMEN: Es necesario un superovulador alternativo para reemplazar el citrato de clomifeno, debido a que está asociado con bajas tasas de preñez. El anastrozol es un superovulador eficaz, sin embargo es poca su investigación. Con el fin de determinar la efectividad del anastrozol como superovulador y compararlo con citrato de clomifeno en situaciones similares, se determinaron los efectos de estos fármacos sobre la expresión de las proteínas de adhesión focal, vinculina e integrina β5, en marcadores de receptividad uterina en días 1 y 6, en las células epiteliales uterinas de ratas Wistar preñadas. Los resultados muestran que la vinculina y la integrina β5 se co-localizan en la base del epitelio uterino al día 1 de la gravidez mientras que al día 6 se desmontan de las adherencias focales basales, co-localizan y aumentan significativamente su expresión apicalmente (p≤0.0001). Además, existe una diferencia significativa en los niveles de expresión de proteína de vinculina e integrina β5 en células epiteliales luminales uterinas entre ratas no tratadas (control) y tratadas con citrato declomifeno (p≤0.0001), ratas tratadas con anastrozol y citrato declomifeno al día 6 (p≤0,0001) sugiriendo la interpretación de que el anastrozol parece mejorar su expresión con el fin de ayudar en el proceso de implantación del blastocisto. Los experimentos de inmunofluorescencia coinciden con los resultados de la expresión de los genes vinculina e integrina β5 en los cuales al día 6 de la preñez, la vinculina y la integrina β5 están significativamente reguladas en células epiteliales luminales uterinas en el grupo tratado con anastrozol con respecto a la muestra del calibrador (p<0,0001). Estos hallazgos sugieren que el anastrozol es favorable para la implantación.

Human neural stem/progenitor cells derived from the olfactory epithelium express the TrkB receptor and migrate in response to BDNF.

Neurogenesis constitutively occurs in the olfactory epithelium of mammals, including humans. The fact that new neurons in the adult olfactory epithelium derive from resident neural stem/progenitor cells suggests a potential use for these cells in studies of neural diseases, as well as in neuronal cell replacement therapies. In this regard, some studies have proposed that the human olfactory epithelium is a source of neural stem/progenitor cells for autologous transplantation. Although these potential applications are interesting, it is important to understand the cell biology and/or whether human neural stem/progenitor cells in the olfactory epithelium sense external signals, such as brain-derived neurotrophic factor (BDNF), that is also found in other pro-neurogenic microenvironments. BDNF plays a key role in several biological processes, including cell migration. Thus, we characterized human neural stem/progenitor cells derived from the olfactory epithelium (hNS/PCs-OE) and studied their in vitro migratory response to BDNF. In the present study, we determined that hNS/PCs-OE express the protein markers Nestin, Sox2, Ki67 and ßIII-tubulin. Moreover, the doubling time of hNS/PCs-OE was approximately 38h. Additionally, we found that hNS/PCs-OE express the BDNF receptor TrkB, and pharmacological approaches showed that the BDNF-induced (40ng/ml) migration of differentiated hNS/PCs-OE was affected by the compound K252a, which prevents TrkB activation. This observation was accompanied by changes in the number of vinculin adhesion contacts. Our results suggest that hNS/PCs-OE exhibit a migratory response to BDNF, accompanied by the turnover of adhesion contacts.

Clinical experience with the use of anti-CdtB and anti-vinculin antibodies in patients with diarrhea in Mexico. / Experiencia clínica con el uso de los anticuerpos anti-CdtB y anti-vinculina en pacientes con diarrea en México.

INTRODUCTION: Circulating anti-CdtB/anti-vinculin antibodies have been validated as biomarkers to distinguish IBS-D from IBD, but there is no experience with them in Latin America. MATERIALS AND METHODS: The analysis was carried out on patients seen at a FGIDs/motility clinic over the last 7 months for diarrhea with abdominal pain and/or bloating who were tested for these antibodies. The patients were diagnosed according to the Rome III criteria or with organic disorders, and those presenting with IBS were further classified as post-infectious (PI) or non-PI-IBS. RESULTS: Thirty patients were studied. Positive biomarkers were found in IBS-D and IBS-D Overlap (58.8%) and IBS-M (33.3%), with no differences between PI-IBS (71.4%) vs. non-PI-IBS (41.7%) subjects (P=.21). There was no positivity in patients with other FGIDs or organic diarrhea, except for one with small intestinal bacterial overgrowth (SIBO). CONCLUSIONS: Our findings support the use of this test as a first-line diagnostic tool to confirm the presence of IBS-D/IBS-M according to the Rome III criteria.

VERO cells harbor a poly-ADP-ribose belt partnering their epithelial adhesion belt.

Poly-ADP-ribose (PAR) is a polymer of up to 400 ADP-ribose units synthesized by poly-ADP-ribose-polymerases (PARPs) and degraded by poly-ADP-ribose-glycohydrolase (PARG). Nuclear PAR modulates chromatin compaction, affecting nuclear functions (gene expression, DNA repair). Diverse defined PARP cytoplasmic allocation patterns contrast with the yet still imprecise PAR distribution and still unclear functions. Based on previous evidence from other models, we hypothesized that PAR could be present in epithelial cells where cadherin-based adherens junctions are linked with the actin cytoskeleton (constituting the adhesion belt). In the present work, we have examined through immunofluorescence and confocal microscopy, the subcellular localization of PAR in an epithelial monkey kidney cell line (VERO). PAR was distinguished colocalizing with actin and vinculin in the epithelial belt, a location that has not been previously reported. Actin filaments disruption with cytochalasin D was paralleled by PAR belt disruption. Conversely, PARP inhibitors 3-aminobenzamide, PJ34 or XAV 939, affected PAR belt synthesis, actin distribution, cell shape and adhesion. Extracellular calcium chelation displayed similar effects. Our results demonstrate the existence of PAR in a novel subcellular localization. An initial interpretation of all the available evidence points towards TNKS-1 as the most probable PAR belt architect, although TNKS-2 involvement cannot be discarded. Forthcoming research will test this hypothesis as well as explore the existence of the PAR belt in other epithelial cells and deepen into its functional implications.