Project description:Abstract Background Chronic constipation is prevalent and involves both colon sensitivity and various changes in intestinal bacteria, particularly mucosa-associated microflora. Here we examined regulatory mechanisms of TRPV4 expression by co-culturing colon epithelial cell lines with intestinal bacteria and their derivatives. We also investigated TRPV4 expression in colon epithelium from patients with constipation. Methods Colon epithelial cell lines were co-cultured with various enterobacteria (bacterial components and supernatant), folate, LPS, or short chain fatty acids (SCFAs). TRPV4 expression levels and promoter DNA methylation were assessed using pyrosequencing, and microarray network analysis. For human samples, correlation coefficients were calculated and multiple regression analyses were used to examine the association between clinical background, rectal TRPV4 expression level and mucosa-associated microbiota. Results Co-culture of CCD841 cells with P. acnes, C. perfringens, or S. aureus transiently decreased TRPV4 expression but did not induce methylation. Co-culture with clinical isolates and standard strains of K. oxytoca, E. faecalis, or E. coli increased TRPV4 expression in CCD841 cells, and TRPV4 and TNF-alpha expression were increased by E. coli culture supernatants but not bacterial components. Although folate, LPS, IL-6, TNF-alpha, or SCFAs alone did not alter TRPV4 expression, TRPV4 expression following exposure to E. coli culture supernatants was inhibited by butyric acid or TNF-alphaR1 inhibitor and increased by p38 inhibitor. Microarray network analysis showed activation of TNF-alpha, cytokines, and NOD signaling. TRPV4 expression was higher in constipated patients from the terminal ileum to the colorectum, and multiple regression analyses showed that low stool frequency, frequency of defecation aids, and duration were associated with TRPV4 expression. Meanwhile, incomplete defecation, time required to defecate, and number of defecation failures per 24 hours were associated with increased E. faecalis frequency. Conclusions Colon epithelium cells had increased TRPV4 expression upon co-culture with K. oxytoca, E. faecalis, or E. coli supernatants, as well as TNFα-stimulated TNFαR1 expression via a pathway other than p38. Butyrate treatment suppressed this increase. Epithelial TRPV4 expression was increased in constipated patients, suggesting that TRPV4 together with increased frequency of E. faecalis may be involved in the pathogenesis of various constipation symptoms.
Project description:BackgroundChronic constipation is prevalent and involves both colon sensitivity and various changes in intestinal bacteria, particularly mucosa-associated microflora. Here we examined regulatory mechanisms of TRPV4 expression by co-culturing colon epithelial cell lines with intestinal bacteria and their derivatives. We also investigated TRPV4 expression in colon epithelium from patients with constipation.MethodsColon epithelial cell lines were co-cultured with various enterobacteria (bacterial components and supernatant), folate, LPS, or short chain fatty acids. TRPV4 expression levels and promoter DNA methylation were assessed using pyrosequencing, and microarray network analysis. For human samples, correlation coefficients were calculated and multiple regression analyses were used to examine the association between clinical background, rectal TRPV4 expression level and mucosa-associated microbiota.ResultsCo-culture of CCD841 cells with P. acnes, C. perfringens, or S. aureus transiently decreased TRPV4 expression but did not induce methylation. Co-culture with clinical isolates and standard strains of K. oxytoca, E. faecalis, or E. coli increased TRPV4 expression in CCD841 cells, and TRPV4 and TNF-alpha expression were increased by E. coli culture supernatants but not bacterial components. Although folate, LPS, IL-6, TNF-alpha, or SCFAs alone did not alter TRPV4 expression, TRPV4 expression following exposure to E. coli culture supernatants was inhibited by butyrate or TNF-alphaR1 inhibitor and increased by p38 inhibitor. Microarray network analysis showed activation of TNF-alpha, cytokines, and NOD signaling. TRPV4 expression was higher in constipated patients from the terminal ileum to the colorectum, and multiple regression analyses showed that low stool frequency, frequency of defecation aids, and duration were associated with TRPV4 expression. Meanwhile, incomplete defecation, time required to defecate, and number of defecation failures per 24 h were associated with increased E. faecalis frequency.ConclusionsColon epithelium cells had increased TRPV4 expression upon co-culture with K. oxytoca, E. faecalis, or E. coli supernatants, as well as TNFα-stimulated TNFαR1 expression via a pathway other than p38. Butyrate treatment suppressed this increase. Epithelial TRPV4 expression was increased in constipated patients, suggesting that TRPV4 together with increased frequency of E. faecalis may be involved in the pathogenesis of various constipation symptoms.
Project description:Comparing gene expression profile in 3T3-F442A adipocytes with shRNA against TRPV4 or GFP. TRPV4 is an ion channel expressed in adipocytes. Results provided information that how loss-of-function of TRPV4 affects gene expression in adipocytes. 4 samples were analyzed as two groups: shGFP (control) and shTRPV4 (experimental). Each group has two replicates.
Project description:Comparing gene expression profile in 3T3-F442A adipocytes with shRNA against TRPV4 or GFP. TRPV4 is an ion channel expressed in adipocytes. Results provided information that how loss-of-function of TRPV4 affects gene expression in adipocytes.
Project description:RNA-seq of TC28a2 cells following TRPV4 activation/inhibition in the presence and absence of prior TGFβ3 stimulation. The experiment was performed to determine the effect of TRPV4 activity on gene expression in the presence and absence of TGFβ stimulation. TGFβ3 was used to stimulate TGFβ signalling, GSK1016790A (GSK101) was used to activate TRPV4, GSK2193874 (GSK219) was used to inhibit TRPV4 and DMSO was used as a vehicle control.
Project description:TRPV4 is a cell surface-expressed calcium-permeable cation channel that mediates cell-specific effects on cellular morphology and function. Dominant missense mutations of TRPV4 cause various forms of inherited neuropathy, but the pathogenic mechanisms are unknown. Using an unbiased screen, we sought to identify novel TRPV4 interactors that may be relevant to disease pathogenesis.
Project description:Degenerative joint disease mainly manifests abnormal bone and cartilage remodeling, articular disc deformation and synovial inflammation, and it is closely related to intraarticular overload. Activation of the mechanosensitive channel transient receptor potential vanilloid 4 (TRPV4) can lead to degeneration of the temporomandibular joint (TMJ) disc. However, the potential mechanism by which TRPV4 leads to TMJ degeneration are still unclear. The results showed that TRPV4 activation promoted upregulation of chemokines including CXCL6 and CXCL13 in disc cells, and such chemokine release facilitated the proliferation and migration of FLSs and aggravated the TMJ degeneration in rat. Mechanistically, TRPV4-induced p38 MAPK signaling pathway activation promoted chemokine expression via the nuclear translocation of p38 and c-Fos, thereby promoting the proliferation and migration by CXCL-CXCR interaction.
Project description:Epigenetic modifications, including the role of miRs in various diseases, are key regulators of gene expression. In this study we aimed to explore whether epigenetic alterations could play a role in the TRPV4-mediated regulation of miR-146a. Here we report that there is no significant differences in the methylation status of the examined 10 CpG sites on miR146a promoter between WT and TRPV4 KO cells under LPS treatment, indicating that the regulation of miR-146a by TRPV4 may not be mediated by methylation changes at these specific sites.
Project description:Intrinsically disordered regions (IDRs) are essential for membrane receptor regulation but often remain unresolved in structural studies. TRPV4, a member of the TRP vanilloid channel family involved in thermo- and osmosensation, has a large N-terminal IDR of approximately 150 amino acids. With an integrated structural biology approach, we analyze the structural ensemble of the TRPV4 IDR and identify a network of regulatory elements that modulate channel activity in a hierarchical lipid-dependent manner through transient long-range interactions. A highly conserved autoinhibitory patch acts as a master regulator by competing with PIP2 binding to attenuate channel activity. Molecular dynamics simulations show that loss of the interaction between PIP2-binding site and the membrane reduces the force exerted by the IDR on the structured core of TRPV4. This work demonstrates that IDR structural dynamics are coupled to TRPV4 activity and highlights the importance of IDRs for TRP channel function and regulation.