ABSTRACT
BACKGROUND@#Abnormal type I collagen (COL1) expression is associated with the development of many cardiovascular diseases. The TGF-beta/Smad signaling pathway and circRNAs have been shown to regulate COL1 gene expression, but the underlying molecular mechanisms are still not fully understood.@*METHODS@#Gain- and loss-of-function experiments were prformed to study the effect of circZBTB46 on the expression of alpha 2 chain of type I collagen (COL1A2). Co-immunoprecipitation assay was performed to observe the interaction between two proteins. RNA immunoprecipitation assay and biotin pull-down assay were performed to observe the interaction of circZBTB46 with PDLIM5.@*RESULTS@#In this study, we investigated the role of circZBTB46 in regulating COL1A2 expression in human vascular smooth muscle cells (VSMCs). We found that circZBTB46 is expressed in VSMCs and that TGF-beta inhibits circZBTB46 formation by downregulating KLF4 expression through activation of the Smad signaling pathway. CircZBTB46 inhibits the expression of COL1A2 induced by TGF-beta. Mechanistically, circZBTB46 mediates the interaction between Smad2 and PDLIM5, resulting in the inhibition of Smad signaling and the subsequent downregulation of COL1A2 expression. Furthermore, we found that the expression of TGF-beta and COL1A2 is decreased, while circZBTB46 expression is increased in human abdominal aortic aneurysm tissues, indicating that circZBTB46-mediated regulation of TGF-beta/Smad signaling and COL1A2 synthesis in VSMCs plays a crucial role in vascular homeostasis and aneurysm development.@*CONCLUSIONS@#CircZBTB46 was identified as a novel inhibitor of COL1 synthesis in VSMCs, highlighting the importance of circZBTB46 and PDLIM5 in regulating TGF-beta/Smad signaling and COL1A2 expression.
ABSTRACT
OBJECTIVE@#To investigate the effect of glycolytic enzyme pyruvate kinase type 2 (PKM2) on the proliferation and apoptosis of human leukemia HL-60 cells.@*METHODS@#si-PKM2 plasmid was transfected into HL-60 cells (set as si-PKM2 group), and blank vector transfected cells were set as control group (si-Ctl group). The expression levels of PKM2 mRNA and protein in si-Ctl group and si-PKM2 group were detected by RT-qPCR and Western blot. CCK-8 cell detection kit was used to detect the proliferation ability of the cells in the two groups. Flow cytometry was used to detect the changes of cell cycle and apoptosis. Western blot and RT-qPCR were used to detect the changes of p-Akt and p-mTOR protein levels in PI3K/Akt/mTOR signaling pathway and the changes of glycolysis-related mRNA levels of the cells in the two groups. The changes in glucose consumption and lactic acid production of the cells were assayed. Over expressed PKM2, HL-60 cells were treated with PI3K inhibitor LY294002 or galactose, the changes in cell proliferation ability, cell cycle and apoptosis, as well as changes in glucose consumption and lactic acid production were detected.@*RESULTS@#Interfered by si-PKM2, mRNA and protein levels of PKM2 in si-PKM2 group significantly decreased, and proliferation ability of the cells was also reduced (P<0.05). After PKM2 knockdown, the cells were significantly blocked at G@*CONCLUSION@#PKM2 knockdown can inhibit the proliferation and induce apoptosis of HL-60 cells, and its molecular mechanism may be related to the PKM2-mediated PI3K/Akt/mTOR-glycolysis, which suggesting that PKM2 may serve as a molecular target for the prevention and treatment of leukemia.
Subject(s)
Humans , Apoptosis , Cell Proliferation , Glycolysis , Phosphatidylinositol 3-Kinases/metabolism , Pyruvate KinaseABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of rapamycin on the expression of survivin and caspase-3 at mRNA level in K562 cells and the influence of rapamycin on K562 cell ultrastructure.</p><p><b>METHODS</b>The effects of rapamycin at various concentration on K562 cell proliferation were analyzed by CCK8; the morphological characteristics of K562 cells was observed by transmission electron microscopy; the expression of survivin and caspase-3 at mRNA level in K562 cells treated with rapamycin was detected by RT-PCR.</p><p><b>RESULTS</b>The proliferation of K562 cells was significantly inhibited by rapamycin. The apoptosis level of K562 cells increased with increase of rapamycin concentration, the expression of survivin at mRNA level decreased with increase of rapamycin concentration (P < 0.05). The expression of caspase-3 at mRNA level increased with increase of rapamycin concentration.</p><p><b>CONCLUSION</b>Rapamycin can prornote K562 cell apoptosis through up-regulating caspase-3 level and reduceing survivin level.</p>