cyclin-d1 and Carotid-Stenosis

Cardiovascular diseases are associated with proliferation and phenotypic switch. Platelet-derived growth factor-BB (PDGF-BB) is a major initiating factor for proliferative vascular diseases, such as neointimal lesion formation, restenosis after angioplasty, and atherosclerosis. Ruxolitinib, a potent Janus kinase (JAK) 1 and 2 inhibitor, has been reported to significantly block the proliferation-related signaling pathway of JAK2/signal transducers and activators of transcription 3 (STAT3) and harbor a broad spectrum of anti-cancer activities, including proliferation inhibition, apoptosis induction, and anti-inflammation. However, the role of ruxolitinib in regulating PDGF-BB-induced VSMC proliferation remains to be elucidated. Thus, this study investigates the role of ruxolitinib in regulating PDGF-BB-induced VSMC proliferation and its underlying mechanisms.. In vivo, the medial thickness of the carotid artery was evaluated using a mouse carotid ligation model, ruxolitinib was administered orally to the mice every other day, and the mice were euthanized on day 28 to evaluate the therapeutic effects of ruxolitinib. Cell proliferation markers were measured using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blotting. In vitro, VSMCs were treated with ruxolitinib with or without PDGF-BB at an indicated time and concentration. Cell proliferation and apoptosis were measured using Cell Counting Kit-8 assay, MTS assays and flow cytometry. The JAK2/STAT3 signaling pathway involved in the effects of ruxolitinib on VSMCs was detected by western blotting with the specific pathway inhibitor AG490.. In vivo, ruxolitinib significantly decreased the ratio-of-intima ratio (I/M ratio) by inhibiting the expression of PCNA and cyclinD1 (p <0.05). In vitro, ruxolitinib inhibited PDGF-BB-induced VSMC proliferation compared with the PDGF-BB treatment group (p <0.05). In addition, ruxolitinib inhibited the PDGF-BB-induced activation of the JAK2/STAT3 signaling pathway and decreased the expression of proliferation related-proteins cyclinD1 and PCNA in VSMCs (p <0.05).. Our findings suggest that ruxolitinib inhibits VSMC proliferation in vivo and in vitro by suppressing the activation of the JAK2/STAT3 signaling pathway. Therefore, ruxolitinib has a therapeutic potential for proliferative vascular diseases.

Topics: Animals; Becaplermin; Carotid Artery, Common; Carotid Stenosis; Cells, Cultured; Cyclin D1; Disease Models, Animal; Hyperplasia; Janus Kinase 2; Janus Kinase Inhibitors; Male; Mice, Inbred C57BL; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Neointima; Nitriles; Proliferating Cell Nuclear Antigen; Pyrazoles; Pyrimidines; Signal Transduction; STAT3 Transcription Factor

Beta-catenin and T cell factor (Tcf) are distal components of the highly conserved Wnt pathway that govern cell fate and proliferation in lower organisms. Thus, we hypothesized that the regulation of beta-catenin and Tcf played a critical role in vascular remodeling. The first objective was to define beta-catenin expression in vascular smooth muscle cells (VSMCs) after balloon injury. Indeed, beta-catenin mRNA and protein were significantly elevated 7 days after balloon injury in the rat carotid artery. We hypothesized that beta-catenin accumulation in response to vascular injury inhibited VSMC apoptosis. In line with our hypothesis, transfection of a degradation-resistant beta-catenin transgene into rat VSMCs significantly inhibited apoptosis. Accumulation of beta-catenin also resulted in a 10-fold increase in the activation of Tcf. To test if Tcf was necessary to confer beta-catenin-induced survival, loss of function studies were carried out with a dominant negative Tcf-4 transgene lacking the beta-catenin binding domain, Tcf4(N31). Indeed, loss of Tcf-4 activity abolished beta-catenin-induced survival. We further postulated that beta-catenin and Tcf promoted cell cycle progression by activating cyclin D1, a target gene of Tcf-4. Beta-catenin activated cyclin D1, and this activation was partially blocked with loss of Tcf-4. In parallel, blockade of Tcf-4 resulted in inhibition of [3H]thymidine incorporation and partial blockade of the G1-S phase transition. In conclusion, beta-catenin and Tcf-4 play a dual role in vascular remodeling by inhibiting VSMC apoptosis and promoting proliferation.

Topics: Amino Acid Substitution; Animals; Apoptosis; beta Catenin; Calcium-Calmodulin-Dependent Protein Kinases; Carotid Arteries; Carotid Stenosis; Catheterization; Cell Cycle; Cell Survival; Cells, Cultured; Cyclin D1; Cytoskeletal Proteins; Disease Models, Animal; Genes, Dominant; Genes, Reporter; Glycogen Synthase Kinase 3; Male; Muscle, Smooth, Vascular; Rats; Rats, Sprague-Dawley; RNA, Messenger; Signal Transduction; TCF Transcription Factors; Trans-Activators; Transcription Factor 7-Like 2 Protein; Transcription Factors; Transgenes; Up-Regulation