Project description:Endothelial barrier integrity is ensured by the stability of the adherens junction (AJ) complexes comprised of VE-cadherin as well as accessory proteins such as β-catenin and p120-catenin. Disruption of the endothelial barrier due to disassembly of AJs results in tissue edema and the influx of inflammatory cells. Using three-dimensional structured illumination microscopy (3D- SIM), we found that the mitochondrial protein Mitofusin-2 (Mfn2) co-localizes at the plasma membrane with VE-cadherin and β-catenin in endothelial cells during homeostasis. Upon inflammatory stimulation, Mfn2 is sulfenylated, the Mfn2/β-catenin complex disassociates from the AJs and translocates into the nucleus where Mfn2 negatively regulates the transcriptional activity of β-catenin. Endothelial-specific deletion of Mfn2 resulted in inflammatory injury, indicating an anti-inflammatory role of Mfn2 in vivo. Our results suggest that Mfn2 acts in a non- canonical manner to suppress the inflammatory response by stabilizing cell-cell adherens junctions and by binding to the transcriptional activator β-catenin.
Project description:Background: Negative-pressure wound therapy has become widely available in modern chronic wound cares. Accelerated keratinocyte (HaCaT cell) movements and decreased E-cadherin expressions induced by the applied negative pressure gradient of 125 mmHg (NP) have been reported in previous studies. However, the molecular mechanism for E-cadherin regulations under NP remains unexplored. We highlighted the signal transduction involved in NP-induced E-cadherin regulation for keratinocytes in the study. Results: Microarray results showed that catenin 1 (CTNND1) gene, the gene encoding the p120-catenin (p120ctn) in cell-cell junctions, was significantly (p = 0.0005) upregulated in HaCaT cells under NP for 12 hours in comparison with those at ambient pressure (AP). Cell fractionations and immunoblotting data showed that NP increased p120ctn phosphorylation, and resulted in p120ctn translocation from the plasma membrane to the cytoplasm. Fluorescent stains suggested that NP diminished the co-localization of p120ctn and E-cadherin on the plasma membrane. Similar phenomenon was also observed in the cells with overexpressed p120ctn at NP. Interestingly, overexpression of dN- p120ctn, a deletion mutant of p120ctn without the N-terminal phosphorylation sites, restored the adherens junctions (AJ) at NP. Knockdown of p120ctn with lentiviral small hairpin RNA not only diminished E-cadherin expressions but also accelerated cell movement at AP. Conclusions: Phosphorylation of p120ctn is endowed to respond rapidly to NP and contributes to the AJ disassembly. This NP-induced E-cadherin downregulation can possibly accelerate wound-healing process. Conclusions: Phosphorylation of p120ctn is endowed to respond rapidly to NP and contributes to the AJ disassembly. This NP-induced E-cadherin downregulation can possibly accelerate wound-healing process. HaCaT cells under negative pressure (NP) gradient of 125 mmHg for 12 hours in comparison with those at ambient pressure (AP) were tested for RNA extraction and hybridization on Affymetrix microarrays. The experiments have been biological replicated three times. The differential expression gene between NP and AP were selected and validated with qPCR method.
Project description:The Adherens Junction protein p120-catenin is implicated in the regulation of cadherin stability, cell migration and inflammatory responses in mammalian epithelial tissues. How these events are coordinated to promote wound repair is not understood. We show that p120-catenin regulates the intrinsic migratory properties or primary mouse keratinocytes, but also influences the migratory behavior of neighboring cells by secreted signals. These events are rooted in the ability of p120-catenin to regulate RhoA-GTPase activity, which leads to a two-tiered control of cell migration. One restrains cell motility via increase of actin stress fibers, reduction in integrin turnover, and an increase in focal adhesions robustness. The other is coupled to the secretion of inflammatory cytokines including Interleukin-24, which causally enhances randomized cell movements. Taken together, our results indicate that p120-RhoA-GTPase-mediated signaling can differentially regulate the migratory behavior of epidermal cells, which has potential implications for chronic wound responses and cancer.
Project description:Background: Negative-pressure wound therapy has become widely available in modern chronic wound cares. Accelerated keratinocyte (HaCaT cell) movements and decreased E-cadherin expressions induced by the applied negative pressure gradient of 125 mmHg (NP) have been reported in previous studies. However, the molecular mechanism for E-cadherin regulations under NP remains unexplored. We highlighted the signal transduction involved in NP-induced E-cadherin regulation for keratinocytes in the study. Results: Microarray results showed that catenin 1 (CTNND1) gene, the gene encoding the p120-catenin (p120ctn) in cell-cell junctions, was significantly (p = 0.0005) upregulated in HaCaT cells under NP for 12 hours in comparison with those at ambient pressure (AP). Cell fractionations and immunoblotting data showed that NP increased p120ctn phosphorylation, and resulted in p120ctn translocation from the plasma membrane to the cytoplasm. Fluorescent stains suggested that NP diminished the co-localization of p120ctn and E-cadherin on the plasma membrane. Similar phenomenon was also observed in the cells with overexpressed p120ctn at NP. Interestingly, overexpression of dN- p120ctn, a deletion mutant of p120ctn without the N-terminal phosphorylation sites, restored the adherens junctions (AJ) at NP. Knockdown of p120ctn with lentiviral small hairpin RNA not only diminished E-cadherin expressions but also accelerated cell movement at AP. Conclusions: Phosphorylation of p120ctn is endowed to respond rapidly to NP and contributes to the AJ disassembly. This NP-induced E-cadherin downregulation can possibly accelerate wound-healing process. Conclusions: Phosphorylation of p120ctn is endowed to respond rapidly to NP and contributes to the AJ disassembly. This NP-induced E-cadherin downregulation can possibly accelerate wound-healing process.
Project description:We report the association of the zonula adherens with a set of mRNAs, through the E-cadherin-p120 catenin binding partner called PLEKHA7.
Project description:The poor prognosis of diffuse gliomas is the consequence of adaptive growth and survival programs coupled to their unsurmountable capacity to infiltrate the brain. Diffuse brain infiltration is a particularly detrimental hallmark of gliomas, however the underlying cellular and signaling mechanisms remain elusive. Histological analysis of glioma samples suggests brain invasion by individual glioma cells extending along blood vessels and nerve tracts, consistent with individual-cell growth and invasion programs. However, using thick 3D tissue sections, we here show that human diffuse gliomas consist of multicellular networks in both tumor center and invasion region. This was confirmed in three orthotopic human glioma xenograft models in mouse brain reflecting neuronal, proneural and mesenchymal subtypes. The connections between glioma cells are provided by either branched filamentous protrusions connecting cells across distance or epithelial-like linear adherens junctions between directly adjacent cells. These intercellular contacts showed dynamic turn-over kinetics, which enabled intercellularly synchronized calcium signaling waves, directionally persistent migration as network and network plasticity. Interference with the stability of adherens junction by downregulating p120-catenin causes irreversibly compromised cell-cell interaction, near-complete inhibition of diffuse brain infiltration and a severe growth defect and marginalized microlesions as outcome. Mining of human glioma cohorts revealed an inverse association of p120 with patient survival and, using next-generation RNA sequencing, profound cell reprogramming with perturbed cell adhesion and axonal guidance pathways was uncovered after p120 downregulation. In conclusion, reminiscent of neuronal and glial progenitor programs during morphogenesis and repair, diffuse gliomas progress as neuronal-like, collective network the subunits of which cooperate by complex cell-cell signaling to promote cell growth and detrimental brain infiltration. Targeting adherens junctions and cell-cell cooperation thus represent unanticipated therapeutic principles to prevent glioma progression.
Project description:Pancreatic cancer is one of the most deadly cancers with a 5 year survival rate of about 5%. Therapeutic options are limited, especially for patients that present with late state disease and metastasis. Although the metastatic burden of pancreatic cancer is usually high, little is known about the mechanisms that regulate delamination and dissemination of epithelial cells from preinvasive and malignant pancreatic lesions. Here, we used a preinvasive mouse model of pancreatic cancer to conditionally knockout p120 catenin (Ctnnd1). Mice with biallelic loss of p120 catenin progressively develop high grade PanIN lesions and neoplasia accompanied by prominent acute and chronic inflammatory processes. Loss of p120 catenin in the context of oncogenic Kras also promotes remarkable apical and basal epithelial cell extrusion. Abundant single epithelial cells exit PanIN epithelium basally, survive, and display features of malignancy. Similar extrusion defects are observed following p120 catenin knockdown in vitro, and these effects are completely abrogated by activation of S1P/S1P2 signaling. Our results establish p120 catenin and S1P/S1P2 signaling as novel regulators of non-EMT mediated epithelial cell invasion in pancreatic neoplasia. Transcriptomes of KCiMist1G; p120wt/wt and KCiMist1G; p120f/f pancreases were compared, with three replicates each, using microarray.
Project description:In nucleated cells, β-catenin, the key downstream effector of this pathway, is a dual function protein, regulating the coordination of gene transcription and cell–cell adhesion. The specific role of β-catenin in the anucleate platelet however remains elusive. Here, we performed a label-free quantitative proteomic analysis of β-catenin immunoprecipitates from human platelets identifying 9 co-immunoprecipitating proteins. GO biological pathway analysis revealed a significant enrichment of specific functional terms including 'cell adhesion', 'cell junction organization' and ‘adherens junction organization'. Our bioinformatics data suggests that human platelet β-catenin may be involved in facilitating cell adhesion and cell junctions. We found three proteins co-immunoprecipitating with β-catenin under both resting and activated conditions, four proteins under resting condition only and two proteins under activated condition only.
Project description:Pancreatic cancer is one of the most deadly cancers with a 5 year survival rate of about 5%. Therapeutic options are limited, especially for patients that present with late state disease and metastasis. Although the metastatic burden of pancreatic cancer is usually high, little is known about the mechanisms that regulate delamination and dissemination of epithelial cells from preinvasive and malignant pancreatic lesions. Here, we used a preinvasive mouse model of pancreatic cancer to conditionally knockout p120 catenin (Ctnnd1). Mice with biallelic loss of p120 catenin progressively develop high grade PanIN lesions and neoplasia accompanied by prominent acute and chronic inflammatory processes. Loss of p120 catenin in the context of oncogenic Kras also promotes remarkable apical and basal epithelial cell extrusion. Abundant single epithelial cells exit PanIN epithelium basally, survive, and display features of malignancy. Similar extrusion defects are observed following p120 catenin knockdown in vitro, and these effects are completely abrogated by activation of S1P/S1P2 signaling. Our results establish p120 catenin and S1P/S1P2 signaling as novel regulators of non-EMT mediated epithelial cell invasion in pancreatic neoplasia.