摘要: Background Vascular smooth muscle cells (VSMC) switch to macrophage-like cells after cholesterol loading, and this change may play an important role in atherogenesis. Muscleblind-like splicing regulator 1 (MBNL1) is a well-known splicing factor that has been implicated in many cellular processes. However, the role of MBNL1 in VSMC macrophage-like transdifferentiation is largely unknown. In this study, we aim to characterize the role of MBNL1-induced gene splicing during atherogenesis. Methods The expression of MBNL1 and Abelson interactor 1 (Abi1) splice variants (Abi1-e10 and Abi1-Delta e10) was compared between artery tissues from healthy donors and atherosclerosis patients. Regulatory mechanisms of MBNL1-induced Abi1 gene splicing were studied, and the signal pathways mediated by Abi1 splice variants were investigated in VSMC. Results Loss of MBNL1 was found in the macrophage-like VSMC (VSMC-M) in artery wall from atherosclerosis patients. In vitro and in vivo evidence confirmed that Abi1 is one of the MBNL1 target genes. Loss of MBNL1 significantly induces the Abi1-Delta e10 isoform expression. Compared to the known actin organization activities of the Abi1 gene, we discovered a novel action of Abi1-Delta e10, whereby Abi1-Delta e10 activates Rac1 independent of upstream stimulation and triggers the Rac1-NOX1-ROS pathway, which results in increased expression of transcription factor Kruppel-like factor 4 (KLF4). While Abi1-Delta e10 inhibits contractile VSMC biomarkers expression and cell contraction, it stimulates VSMC proliferation, migration and macrophage-like transdifferentiation. Conclusion Loss-of-function of MBNL1 activates VSMC-M transdifferentiation to promote atherogenesis through regulating Abi1 RNA splicing.

摘要: Objectives Mouse embryonic stem cells (ESCs) are derived from the inner cell mass of blastocyst-stage embryos and cultured in different culture media with varied pluripotency. Sporadically, a small population of ESCs exhibit 2-cell stage embryonic features in serum containing medium. However, whether ESCs can transit into 2-cell embryo-like (2C-like) cells in the chemically defined media remains largely unknown. Materials and Methods We established a robust in vitro induction system, based on retinoic acid (RA) containing chemically defined media, which can efficiently increase the subpopulation of 2C-like cells. Further test the pluripotency and 2C features of ESCs cultured in RA. 2C reporter-positive cells were selected by FACS; the level of protein was detected via immunofluorescence staining and western blot; the level gene expressions were measured by RNA-seq. Results Retinoic acid drives a NELFA (negative elongation factor A)-mediated 2C-like state in mouse ESCs, characterized with 2C-specific transcriptional networks and the ability to contribute trophectoderm (TE) when injected into developing embryos. In addition, RA treatment triggers DNA hypomethylation, active histone modification, suppressed glycolysis metabolism and reduced protein synthesis activity of ESCs. Conclusions We showed that RA has a broader role in 2C-like cells state, not only is one of the upstream regulators of the 2C-like state in chemically defined media but also illuminates genetic and epigenetic regulations that govern ESCs to 2C-like transition.

摘要: Purpose We investigated the role of farnesoid X receptor (FXR), a ligand-dependent transcription factor, in renal ischaemia-reperfusion (I/R) injury. Materials and Methods We performed unilateral renal I/R model in FXR knockout (Fxr(-/-)) and wild-type (WT) mice in vivo and a hypoxia-reoxygenation (H/R) model in vitro. The pathways by which FXR induces apoptosis were detected using a proteome profiler array. The effects of FXR on apoptosis were evaluated using immunoblotting, TUNEL assays and flow cytometry. Results Compared with WT mice, Fxr(-/-) mice showed improved renal function and reduced tubular injury scores and apoptosis. Consistent with the in vivo results, the silencing of FXR decreased the number of apoptotic HK-2 cells after H/R, while FXR overexpression aggravated apoptosis. Notably, bone marrow transplantation (BMT) and immunohistochemistry experiments revealed the involvement of FXR in the tubular epithelium rather than in inflammatory cells. Furthermore, in vivo and in vitro studies demonstrated that FXR deficiency increased phosphorylated Bcl-2 agonist of cell death (p-Bad) expression levels and the ratio of Bcl-2/Bcl-xL to Bax expression in the kidney. Treatment with wortmannin, which reduced p-Bad expression, inhibited the effects of FXR deficiency and eliminated the tolerance of Fxr(-/-) mouse kidneys to I/R injury. Conclusions These results established the pivotal importance of FXR inactivation in tubular epithelial cells after I/R injury. FXR may promote the apoptosis of renal tubular epithelial cells by inhibiting PI3k/Akt-mediated Bad phosphorylation to cause renal I/R damage.

摘要: Objectives Nodakenin (NK) is a coumarin glucoside that is found in the roots of Angelicae gigas. A limited number of studies have been conducted on the pharmacological activities of NK. Although NK is an important natural resource having anti-inflammatory and antioxidant effects, no investigation has been conducted to examine the effects of NK on obesity and obesity-induced inflammation. Materials and Methods The present study investigated the therapeutic effects of NK treatment on obesity and its complications, and its mechanism of action using differentiated 3T3-L1 adipocytes and high-fat diet (HFD)-induced obese mice. Oil red O staining, western blot assay, qRT-PCR assay, siRNA transfection, enzyme-linked immunosorbent assay, H&E staining, immunohistochemistry, molecular docking and immunofluorescence staining were utilized. Results Treatment with NK demonstrated anti-adipogenesis effects via the regulation of adipogenic transcription factors and genes associated with triglyceride synthesis in differentiated 3T3-L1 adipocytes. Compared with the control group, the group administered NK showed a suppression in weight gain, dyslipidaemia and the development of fatty liver in HFD-induced obese mice. In addition, NK administration inhibited adipogenic differentiation and obesity-induced inflammation and oxidative stress via the suppression of the VLDLR and MEK/ERK1/2 pathways. This is the first study that has documented the interaction between NK and VLDLR structure. Conclusion These results demonstrate the potential of NK as a natural product-based therapeutic candidate for the treatment of obesity and its complications by targeting adipogenesis and adipose tissue inflammation-associated markers.

摘要: Objectives Large bone defects are a common, debilitating clinical condition that have substantial global health and economic burden. Bone tissue engineering technology has become one of the most promising approaches for regenerating defective bones. In this study, we fabricated a naringin-inlaid composite silk fibroin/hydroxyapatite (NG/SF/HAp) scaffold to repair bone defects. Materials and Methods The salt-leaching technology was used to fabricate the NG/SF/HAp scaffold. The cytocompatibility of the NG/SF/HAp scaffold was assessed using scanning electron microscopy, live/dead cell staining and phalloidin staining. The osteogenic and angiogenic properties were assessed in vitro and in vivo. Results The porous NG/SF/HAp scaffold had a well-designed biomimetic porous structure with osteoinductive and angiogenic activities. A gene microarray identified 854 differentially expressed genes between human umbilical cord-derived mesenchymal stem cells (hUCMSCs) cultured on SF-nHAp scaffolds and cells cultured on NG/SF/HAp scaffolds. The underlying osteoblastic mechanism was investigated using hUCMSCs in vitro. Naringin facilitated hUCMSC ingrowth into the SF/HAp scaffold and promoted osteogenic differentiation. The osteogenic and angiogenic capabilities of cells cultured in the NG/SF/HAp scaffold were superior to those of cells cultured in the SF/HAp scaffold. Conclusions The data indicate the potential of the SF/HAp composite scaffold incorporating naringin for bone regeneration.