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Cardiovascular calcification was originally considered a passive, degenerative process, however with the advance of cellular and molecular biology techniques it is now appreciated that ectopic calcification is an active biological process. Vascular calcification is the most common form of ectopic calcification, and aging as well as specific disease states such as atherosclerosis, diabetes, and genetic mutations, exhibit this pathology. In the vessels and valves, endothelial cells, smooth muscle cells, and fibroblast-like cells contribute to the formation of extracellular calcified nodules. Research suggests that these vascular cells undergo a phenotypic switch whereby they acquire osteoblast-like characteristics, however the mechanisms driving the early aspects of these cell transitions are not fully understood. Osteoblasts are true bone-forming cells and differentiate from their pluripotent precursor, the mesenchymal stem cell (MSC); vascular cells that acquire the ability to calcify share aspects of the transcriptional programs exhibited by MSCs differentiating into osteoblasts. What is unknown is whether a fully-differentiated vascular cell directly acquires the ability to calcify by the upregulation of osteogenic genes or, whether these vascular cells first de-differentiate into an MSC-like state before obtaining a "second hit" that induces them to re-differentiate down an osteogenic lineage. Addressing these questions will enable progress in preventative and regenerative medicine strategies to combat vascular calcification pathologies. In this review, we will summarize what is known about the phenotypic switching of vascular endothelial, smooth muscle, and valvular cells.
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Objective To explore the role of long noncoding RNA-MGC (lnc-MGC) on the trans-differentiation of human peritoneal mesothelial cells (HPMCs) induced by high glucose.Methods The immortalized HPMCs were used to establish control group and high glucose group (60mmol/L) respectively.Cells in control group were cultured with ordinary cell medium,and in high glucose group were stimulated with high glucose medium for 72h.Changes of lnc-MGC expression in the both groups were measured by RT-PCR,and the changes of mRNA and protein expression of E-Cadherin,α smooth muscle actin (α-SMA),connective tissue growth factor (CTGF),type Ⅰ collagen (COL-1) and type Ⅲ collagen (COL-3) in epithelial cells of both groups were measured by RT-PCR and Western blotting.The HPMCs were transfected with lentivirus,and then the changes of the above indexes were observed after up-and down-regulation of lnc-MGC.Results By high glucose stimulation of HPMCs for 72h,RTPCR results showed that the expressions oflnc-MGC,α-SMA,CTGF,COL-1 and COL-3 mRNA increased obviously (P＜0.05),and the expression of E-Cadherin mRNA decreased markedly (P＜0.05) in high glucose group than in control group;Western-blotting results indicated that the expression of protein was consistent with that of mRNA,and the differences were statistically significant (P＜0.05).After lentivirus transfection and down-regulation oflnc-MGC,RT-PCR results showed that the expressions of lnc-MGC,α-SMA,CTGF,COL-1 and COL-3 mRNA decreased obviously (P＜0.05),and the expression of E-Cadherin mRNA increased markedly (P＜0.05) in high glucose group than in control group;Western-blotting results showed that the expression of protein was consistent with that of mRNA,and the differences were statistically significant (P＜0.05).After lentivirus transfection and upregulation of lnc-MGC,RT-PCR results showed that the expressions of lnc-MGC,α-SMA,CTGF,COL-1 and COL-3 mRNA increased significantly (P＜0.05),and the expression of E-Cadherin mRNA decreased obviously (P＜0.05) in high glucose group than in control group;Western blotting results showed that the expression of protein was consistent with that of mRNA,and the differences were statistically significant (P＜0.05).The downstream target was predicted as miRNA126-3p,and compared with the control group,the expression ofmiRNA126-3p increased (P＜0.05) after high glucose stimulation,and after transfection with down regulated lnc-MGC lentivirus,the expression of miRNA126-3p decreased obviously (P＜0.05),and transfection with up regulated lnc-MGC lentivirus,the expression ofmiRNA126-3p increased obviously (P＜0.05).Conclusions lnc-MGC participates in the process of HPMCs transdifferentiation through regulating miRNA126-3p.Regulation oflnc-MGC expression level may control the phenotype transition of HPMCs,and delay the development of peritoneal fibrosis.
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Objective To explore the role of Kruppel-like factor 4 (KLF-4) in phenotypic transition of human peritoneal mesothelial cells (HPMCs) induced via high glucose. Methods HPMCs were induced by 50mmol/L glucose for 72 hours, the expressions of epithelium-cadherin (E-cadherin), KLF-4, α-smooth muscle actin (-SMA), connective tissue growth factor (CTGF) and miRNA-143 were detected by Real-time PCR and Western blotting, respectively. The treated cells were transfected with LVKLF-4 and inhibitor, the untreated cells were transfected with shRNA-KLF-4 and mimic. The mRNA and protein expressions of KLF-4, E-cadherin, α-SMA, CTGF and miRNA-143 were detected by Real-time PCR and Western blotting, respectively. Results Real-time PCR showed that the expression of E-cadherin decreased and of α-SMA, CTGF and miRNA-143 increased, but of KLF-4 not changed in high glucose treated cells. Western blotting showed that the expression of KLF-4 and E-cadherin decreased. Upregulating KLF-4 increased the expression of E-cadherin, but decreased the expression of α-SMA and CTGF. Down-regulating KLF-4 decreased the expression of E-cadherin, but augment the expression of α-SMA and CTGF. Conclusion High glucose may induce the down-regulation of KLF-4 protein, and SRF- miRNA-143-KLF-4 signal pathway axis may be involved in the process of HPMC phenotypic transition.
