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:The mechanosensitive ion channels Transient Receptor Potential Vanilloid 4 (TRPV4) and PIEZO1 transduce physiologic and supraphysiologic magnitudes of mechanical signals in the chondrocyte, respectively. TRPV4 activation promotes chondrogenesis, while PIEZO1 activation by supraphysiologic deformations drives cell death. The mechanisms by which activation of these channels discretely drives changes in gene expression to alter cell behavior remains to be determined. To date, no studies have contrasted the transcriptomic response to activation of these channels, nor has any published data attempted to correlate these transcriptomes to alterations in cellular function. This study used RNA sequencing to comprehensively investigate the transcriptomes associated with activation of TRPV4 or PIEZO1, revealing that TRPV4 and PIEZO drive distinct transcriptomes, but also exhibit unique co-regulated clusters of genes. Notably, activation of PIEZO1 through supraphysiologic deformation induced a transient inflammatory profile that overlapped with the interleukin (IL)-1-responsive transcriptome and contained genes associated with cartilage degradation and osteoarthritis progression. However, both TRPV4 and PIEZO1 were also shown to elicit anabolic effects. PIEZO1 expression promoted a pro-chondrogenic transcriptome under unloaded conditions, and daily treatment with PIEZO1 agonist Yoda1 significantly increased sulfated glycosaminoglycan deposition in vitro. These findings emphasize the presence of a broad “mechanome” with distinct effects of TRPV4 and PIEZO1 activation in chondrocytes, suggesting complex roles for PIEZO1 in both the physiologic and pathologic responses of chondrocytes. The identification of transcriptomic profiles unique to or shared by PIEZO1 and TRPV4 (distinct from IL-1-induced inflammation) could inform future therapeutic designs targeting these channels for the management and treatment of osteoarthritis.