Vinculin is a cytoskeletal protein associated with cell-cell and cell-matrix junctions, playing an important role in linkage of integrin adhesion molecules to the actin cytoskeleton. The planarian nervous system is a fascinating system for studying the organogenesis during regeneration. In this paper, a homolog gene of Vinculin, DjVinculin, was identified and characterized in Dugesia japonica. The DjVinculin sequence analysis revealed that it contains an opening reading frame encoding a putative protein of 975 amino acids with functionally domains that are highly conserved, including eight anti-parallel alpha-helical bundles organized into five distinct domains. Whole mount in situ hybridization showed that DjVinculin was predominantly expressed in the brain of intact and regenerating planarians. RNA interference of DjVinculin caused distinct defects in brain morphogenesis and influences the regeneration of planarian GABAergic neurons. The expression level of DjGAD protein was decreased in the DjVinculin-knockdown planarians. These findings suggest that DjVinculin is required for GABAergic neurons regeneration.
Transmembrane protein 18 (Tmem18) is an obesity-associated gene essential for adipogenesis; however, its function in the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) is still unclear. In this study, we found that Tmem18 was significantly downregulated in rat BMSCs after osteogenic induction. TMEM18 overexpression remarkably downregulated osteo-specific genes including alkaline phosphatase (Alp), Runt-related transcription factor 2 (Runx2), osteocalcin (Ocn), and osteopontin (Opn), and reduced the number of mineral deposits and ALP activity in vitro, whereas knockdown of Tmem18 yielded the opposite results. In vivo assays also indicated that TMEM18 knockdown BMSCs have an increased bone formation potential in a rat model of calvarial defects. Analyses of the mechanism suggested that TMEM18 overexpression decreased beta-catenin expression, whereas the TMEM18 knockdown enhanced beta-catenin expression and promoted its nuclear translocation. The positive effects on osteogenic differentiation of rat BMSCs owing to the TMEM18 knockdown were attenuated by beta-catenin downregulation. Taken together, these results indicate that TMEM18 plays an inhibitory role in osteogenic differentiation of BMSCs via inactivation of beta-catenin.
TGF-beta-activated kinase 1 (TAK1) plays a pivotal role in Toll-like receptor (TLR) signaling pathway. However, the mechanisms controlling its activity remain poorly understood. Here, we show that leucine-rich repeat containing 62 (LRRC62), a previously uncharacterized protein, negatively regulates TLR signaling by targeting TAK1. Expression of LRRC62 inhibits the TLRs-induced production of pro-inflammatory cytokine, whereas deficiency in LRRC62 enhances the activation of NF-kappa B and MAPK signaling and increases the production of pro-inflammatory cytokines. Mechanically, LRRC62 functions as an adaptor to recruit deubiquitinase CYLD to TAK1, thus inhibits the K63-linked poly-ubiquitination and activation of TAK1. Together, our findings uncover an unrecognized mechanism by which LRRC62 antagonizes the activation of TAK1 in a CYLD-mediated deubiquitination-dependent manner, thereby balancing Toll-like receptor signaling to avert overzealous inflammation.
Brain-derived neurotropic factor (BDNF) deficiency in Schwann cells plays an important role in the pathogenesis of diabetic peripheral neuropathy (DPN). Little is known about the mechanism involved in BDNF downregulation in Schwann cells in DPN. In this study, we first confirmed downregulation of BDNF and neurotrophin 3 expression in the sciatic nerves of diabetic mice, which was accompanied by myelin sheath abnormalities. Moreover, in vitro, high glucose was revealed to cause downregulation of BDNF, but not neurotrophin 3, expression in RSC96 cells, which was accompanied by DNA hypermethylation of BDNF promoters I and II DNMT1 was subsequently revealed to be enhanced at the mRNA and protein levels in high glucose-stimulated RSC96 cells, and inhibition of DNMT1 with 5-Aza treatment or shRNA vector transfection reversed high glucose-induced reductions in BDNF expression. Furthermore, the mTOR and upstream Akt pathways were indicated to mediate high glucose-induced DNMT1 and BDNF expression in RSC96 cells. Taken together, our results suggest that the Akt/mTOR cascade mediates high glucose-induced reductions in BDNF via DNMT1 in Schwann cells in DPN.
Low-intensity pulsed ultrasound (LIPUS) is a noninvasive therapeutic method which gradually being used in clinic including cancers. Exosomes mediate intercellular communication functions in disease development and the potential clinical applications in diagnosis and therapy. However, few studies have discussed the relationship between LIPUS and exosomes. Herein, we show that low intensity (0.6-2.1 W/cm(2) or 0.6-3.4 W/cm(2)) LIPUS promoted exosomes secretion whereas higher intensity (3.4-5.0 W/cm (2) or 5.0 W/cm(2)) LIPUS inhibited exosomes secretion, and this phenomenon is associated with autophagy. Pretreatment with 3-MA or down-regulation of LC3 potentiated low intensity LIPUS's promotion of exosomes secretion and conferred resistance to higher intensity LIPUS's effects on exosomes secretion. Furthermore, pretreatment with PP242 attenuated LIPUS-influenced exosomes secretion while expression of constitutively active Akt (Ad-myr-Akt) elevated LIPUS-influenced exosomes secretion, implying mTOR-dependent mechanism involved. The findings indicate that LIPUS influences exosomes secretion by targeting mTOR-mediated LC3 signaling in SPC-A1 and SPC-A1-BM cells. Our data provided initial evidence to connect LIPUS and secretion of exosomes, and highlight that LIPUS may be exploited in exosome-related diseases.
NEDD4 is an E3 ubiquitin ligase containing the HECT domain, which regulates various cellular processes, but its role in vascular endothelial cells is unknown. In the present study, we found that NEDD4 bound directly to XPO1 by co-immunoprecipitation screening. In HUVECs (human umbilical vein endothelial cells), overexpression of NEDD4 reduced Ang II-induced ROS level and cell apoptosis. Ang II stimulation led to nuclear accumulation of cargoes, while overexpression of NEDD4 enhanced the XPO1-dependent nuclear export of its cargoes. KPT185, an inhibitor of XPO1, can abolished the protective effect of NEDD4 under Ang II treatment. In addition, NEDD4 could promote the interaction between XPO1 and RanBP3 via K63-linked ubiquitination of XPO1. These results suggested that NEDD4 played a protective role in vascular endothelial cell injury through regulating XPO1-mediated nuclear export.
Recent studies have shown that the expression levels of glucose-regulated protein 78 (GRP78) and homeobox B9 (HOXB9) are both upregulated in hepatocellular carcinoma (HCC) and are closely related to HCC invasion and metastasis. However, whether there is a regulatory relationship between GRP78 and HOXB9 is unclear. In this study, we examined the expression of GRP78 and HOXB9 in HCC tissues and adjacent nontumor tissues. Correlation analysis indicated that GRP78 and HOXB9 expression were positively correlated. High levels of GRP78 and HOXB9 expression are closely related to worse clinicopathological features. Knockdown of GRP78 in HCC cells decreased the mRNA and protein expression of HOXB9, but increase HOXB9 expression reversed the decrease in invasion and metastasis induced by knocking down GRP78. Further experiments showed that GRP78 regulates HOXB9 through the Wnt signaling pathway by chaperoning low-density lipoprotein receptor-related protein 6 (LRP6). Importantly, we found that GPR78 promoted maturation of LRP6, while knockdown of GRP78 led to LRP6 misfolding and endoplasmic reticulum-associated degradation (ERAD). Consequently, the levels of mature LRP6 were reduced, and Wnt/HOXB9 signaling was inhibited. Our data suggest that the GRP78-LRP6-HOXB9 axis regulates the invasion and metastasis of HCC and may represent a potential therapeutic target for the treatment of HCC.
Long non-coding RNAs (lncRNAs) have been confirmed crucial regulators in tumorgenesis. Small nucleolar RNA host gene 16 (SNHG16) has been recently shown to be dysregulated, which uncovered to be a potential oncogene in some cancers. However, the biological function and potential mechanism of SNHG16 in hepatocellular carcinoma (HCC) remain unclear. In our study, our observations showed that the expression level of SNHG16 in HCC tissues and cell lines was upregulated compared with adjacent noncancerous tissues and normal cells. In vitro, loss-of-function experiments revealed that SNHG16 knockdown suppressed the proliferation and weakened invasion of SMMC7721 and HepG2 cells. miR-195 expression was significantly decreased in HCC tissues and negatively correlated with SNHG16 expression. Furthermore, RIP and dual luciferase reporter assays showed that SNHG16 acted as an endogenous sponge by directly binding to miR-195 and downregulated its expression. SNHG16 overexpression inverted the inhibitory effect of miR-195 on proliferation and invasion of SMMC7721 and HepG2 cells. Additionally, SNHG16 depletion resulted in lower tumor growth and weight loss, in vivo. In conclusion, our findings reported that the oncogenic role of SNHG16 in HCC tumorigenesis through a novel SNHG16-miR-195 axis, which provided a novel insight for HCC and helped to probe a potential therapeutic target for the deadly disease.
Oxaliplatin has been widely applied in clinical tumor chemotherapy, the treatment failure of which mainly blames on low susceptibility resulted from intrinsic or acquired drug resistance in tumor cells. Microenvironmental hypoxia is one of the important pathological features of solid tumors, which is closely related to the radiochemotherapy tolerance and poor prognosis. Cinnamaldehyde is extracted from Cinnamomum cassia with inhibiting effect against kinds of tumors. In this study, we demonstrated that hypoxia reduced the sensitivity to oxaliplatin in colorectal cancer (CRC) cells via inducing EMT and stemness. Nonetheless, cinnamaldehyde increased the curative effect of oxaliplatin by promoting apoptosis both in vitro and in vivo. Mechanistically, cinnamaldehyde and oxaliplatin synergistically reversed hypoxia-induced EMT and sternness of CRC cells and suppressed hypoxia-activated Wnt/beta-catenin pathway synergistically. These consequences uncovered the potential therapeutic value of cinnamaldehyde and provided novel ideas on improving the sensitivity of oxaliplatin in CRC therapy.
Angiogenesis plays important roles in solid tumors progression. Growth factors such as vascular endothelial growth factors (VEGFs) can induce angiogenesis and hypoxia promotes the expression of VEGFs through activating hypoxia-inducible factor 1 (HIF-1 alpha). However, the regulation of HIF-1 alpha still not been fully understood. Here, we demonstrate that the Sine Oculis Homeobox Homolog 4 (SIX4) is up-regulated in colorectal cancer (CRC) and high expression of SIX4 predicts a poor prognosis. Overexpression of SIX4 enhances tumor growth and angiogenesis in vitro and in vivo, while knockdown of SIX4 inhibits tumor growth and angiogenesis. Furthermore, we show that SIX4 increases the expression of VEGF-A by coordinating with the HIF-1 alpha. Mechanically, we explore that SIX4 up-regulates the expression of HIF-1 alpha depending on Akt activation. Collectively, we demonstrate that SIX4 is functional in regulating tumor angiogenesis and SIX4 might be used as anti-angiogenic therapy in CRC.
Myofibroblasts are characterized by de novo expression of a-smooth muscle actin (alpha-SMA) and play a key role in tissue repair and remodeling. In addition to TGF-beta 1, recent studies have shown that nerve growth factor (NGF) has effects on myofibroblast differentiation and collagen synthesis. However, the regulatory mechanism remains poorly defined. NGF effects are mediated by the specific expression of the NGF neurotrophic tropomyosin-receptor kinase A (TrkA) and p75 neurotrophin receptor (p75(NTR)). Using NIH/3T3 fibroblast cell lines, we examined the induction of myofibroblast differentiation stimulated by NGF. Our findings showed that p75(NTR) was in keeping with the expression of alpha-SMA. Herein, we investigated the role of p75(NTR) in NGF-induced myofibroblast differentiation and collagen synthesis in these cells using lentivirus transfection to overexpress and knock down. Our results showed that p75 NTR was preferentially expressed and was sufficient to induce actin cytoskeleton remodeling, which was required for NGF-induced alpha-SMA expression. Furthermore, NGF induced nuclear translocation of MRTF-A, an effect that was regulated by p75(NTR), and required for alpha-SMA and collagen-I expression in myofibroblasts. Using a novel MRTF-A pathway inhibitor, CCG-203971, we further demonstrated the requirement of MRTF-A nuclear localization and activity in NGF-induced alpha-SMA expression. In conclusion, we conclude that p75(NTR) regulates NGF-induced myofibroblast differentiation and collagen synthesis through MRTF-A. Regulation of NGF-p75(NTR) interactions represents a promising therapy for fibrotic disorders.
Sepsis is characterized as exceed inflammation response and multiple organs dysfunction. Many articles suggested that mesenchymal stem cells can alleviate the inflammation and improve the survival rate of inflammatory animal models, however, the mechanism is still unclear. This study aimed to test the hypothesis that rat adipose-derived mesenchymal stem cells (ADMSCs) produce a amount of soluble tumour necrosis factor receptor 1 (sTNFR1), which ameliorated liver injury and inflammation and increased the survival rate of septic rat model.120 adult male Sprague-Dawley rats were randomly divided into 4 groups: sham-operated (Sham), sepsis-induced by cecal ligation and puncture (CLP), shNC (injected 1 x 10(6) ADMSCs with transfected with scramble shRNA 1 h after CLP), and shsTNFR1 (injected 1 x 10(6) ADMSCs with transfected with sTNFR1 1 h after CLP). The serum sTNFR1 levels were the lowest in Sham and highest in shNC group. ADMSCs could decrease the levels of pro-inflammatory cytokines such as TNF-alpha, IL-6, AP-1 c-jun and NF-kappa B p56 after CLP administration, whereas this result was weaken by shsTNFR1 administration. Moreover, shNC had an increased levels of the anti-inflammatory factor IL-10 compared with CLP, and this change could be weakened in shsTNFR1 administration. More importantly, ADMSCs could improve the survival rate of CLP-induced septic rats. Therapeutically administered ADMSCs secrete sTNFR1, which alleviated the liver injury and inflammatory response. Additionally, ADMSCs also ameliorated the systematic inflammation and increased the survival rate of septic rats.
Background/Aims: The NOD-like receptor, pyrin domain containing-3 (NLRP3) inflammasome is involved in the progression of chronic kidney disease in several rodent models. Here, we investigated whether a specific inhibitor of NLRP3 inflammasome, MCC950, can attenuate cisplatin-induced renal fibrosis. Materials: Renal fibrosis was induced via a series of three injections of cisplatin to male C57BL/6 mice (7.5 mg/ kg body weight). Activation of NLRP3 inflammasome was detected by immunoblotting, real-time PCR, and immunofluorescence. To validate the protective effect of NLRP3 inflammasome inhibition, MCC950(20 mg/kg body weight) was daily injected into multiple-cisplatin-treated mice intraperitoneally for 14 days, starting from 4 weeks after the first dose of cisplatin. NLRP3(-/-) mice were used to confirm the role of NLRP3 inflammasome in cisplatin-induced renal fibrosis. Results: Mice were euthanized at 6 weeks after the first dose of cisplatin treatment. In multiple-cisplatin-induced murine model, renal fibrosis was accompanied by the activation of NLRP3 inflammasome. MCC950, the specific inhibitor of NLRP3 inflammasome, reduced cisplatin-induced renal dysfunction, tubular damage, interstitial collagen deposit, and the expression of profibrotic parameters. NLRP3 inhibition might protect against cisplatin-induced renal fibrosis through the alleviation of oxidative stress and inflammation. Furthermore, inhibition of NLRP3 inflammasome activation by deleting NLRP3 gene halted the progression of cisplatin-induced renal fibrosis. Conclusion: Inhibition of NLRP3 inflammasome attenuates renal fibrosis due to repeated cisplatin injections, and might be identified as a potential target for attenuating cisplatin-induced chronic kidney disease.
Endothelial-mesenchymal transition (EndoMT) is a key step during lung fibrosis. Studies have shown that bone marrow mesenchymal stem cells (BMSCs) may act as therapeutic candidates for lung fibrosis. However, the effects of BMSCs on EndoMT induced by SiO2 have not been elucidated, and means to label and track grafted cells have been lacking. The current study explored whether BMSCs prevented pulmonary fibrosis by targeting EndoMT, as well as analyzed the distribution of BMSCs labeled with superparamagnetic iron oxide (SPIO) nanoparticles during treatment. TIE2-GFP mice, human umbilical vein endothelial cells (HUVECs), and BMSCs labeled with SPIO nanoparticles were used to explore the distributions and therapeutic effects of BMSCs in vivo and in vitro. We found that BMSCs reversed lung fibrosis by targeting EndoMT in vivo. Furthermore, we show that BMSCs labeled with SPIO nanoparticles could be used to track stem cells reliably in the lungs for 14 days. Conditioned medium from BMSCs attenuated the increased functional changes and reversed the SiO2-induced upregulation of ER stress and autophagy markers irrespective of whether they were nanoparticle labeled or not. Our findings identify novel methods to track labeled BMSCs with therapeutic potential.
Gemcitabine (GEM)-based chemotherapy is commonly used to treat pancreatic cancer. However, acquired resistance to GEM remains a challenge in pancreatic cancer patients. Here we tested whether cancer-associated fibroblasts (CAFs) play vital roles in regulating drug resistance by transferring exosomal miRNA to cancer cells. CAFs were isolated from primary fibroblast of pancreatic cancer patients, and exosomes were collected and identified through transmission electron microscopy and western blotting analysis. The functions of CAFs-derived exosomal miRNA in regulating drug resistance were further investigated. We found that CAFs were innately resistant to GEM. The conditioned medium (CM) and the exosomes derived from CAFs contributed to GEM resistance, and GEM treatment further enhanced the effect of CAFs or CAFs-exosomes on pancreatic cancer cells proliferation. MiR-106b level was upregulated in CAFs and CAFs-exosomes following GEM treatment. MiR-106b was directly transferred from CAFs to pancreatic cancer cells through exosomes. Pretreatment of CAFs with miR-106b inhibitor suppressed miR-106b expression in CAFs-exosomes and resulted in a decreased resistance of cancer cells to GEM. MiR-106b promoted GEM resistance of cancer cells by directly targeting TP53INP1. Summarily, our data demonstrated that CAFs-derived exosomal miR-106b plays a vital role in causing GEM resistance of pancreatic cancer, thus offering a new target for sensitizing pancreatic cancer cells to GEM.