Targeted binding of estradiol with ESR1 promotes proliferation of human chondrocytes by inhibiting activation of ERK signaling pathway / 南方医科大学学报

OBJECTIVE@#To investigate the effect of estradiol (E2)/estrogen receptor 1 (ESR1) on the proliferation of human chondrocytes and explore the molecular mechanism.@*METHODS@#The Ad-Easy adenovirus packaging system was used to construct and package the ESR1-overexpressing adenovirus Ad-ESR1. Western blotting and qPCR were used to detect the expression of ESR1 protein and mRNA in human chondrocyte C28I2 cells. In the cells treated with different adenoviruses, the effects of E2 were tested on the expressions of proteins related with cell autophagy and apoptosis and the phosphorylation of ERK signaling pathway using Western blotting. Immunofluorescence assay was used to observe the intracellular autophagic flow, flow cytometry was performed to analyze the cell apoptosis rate and the cell cycle changes, and qPCR was used to detect the expressions of PCNA, cyclin B1 and cyclin D1 mRNAs. The inhibitory effect of the specific inhibitor of ERK on the expressions of autophagy- and apoptosis-related genes at both the protein and mRNA levels were detected using Western blotting and qPCR.@*RESULTS@#Transfection with the recombinant adenovirus overexpressing ESR1 and E2 treatment of C28I2 cells significantly enhanced the expressions of autophagy-related proteins LC3, ATG7, promoted the colocalization of LC3 and LAMP1 in the cytoplasm, increased the expressions of the proliferation-related marker genes PCNA, cyclin B1 and cyclin D1, and supressed the expressions of cleaved caspase-3, caspase-12 and pERK. RNA interference of ESR1 obviously lowered the expression levels of autophagy-related proteins in C28I2 cells, causing also suppression of the autophagic flow, increments of the expressions of apoptosis-related proteins and pERK, and down-regulated the expressions of the proliferation marker genes. Blocking ERK activation with the ERK inhibitor obviously inhibited the effects of E2/ESR1 on autophagy, proliferationrelated gene expressions and cell apoptosis.@*CONCLUSIONS@#The targeted binding of E2 with ESR1 promotes the proliferation of human chondrocytes possibly by inhibiting the activation of ERK signaling pathway to promote cell autophagy and induce cell apoptosis.

Association of autophagy related gene polymorphisms with neutrophilic airway inflammation in adult asthma

BACKGROUND/AIMS: Role of autophagy in neutrophil function and the association of autophagy and autophagy related (ATG) gene polymorphisms with asthma susceptibility were suggested. In this study, we investigated the genetic association of ATG5 and ATG7 polymorphisms with asthma risk, severity and neutrophilic airway inflammation. METHODS: We recruited 408 asthma patients and 201 healthy controls. Sputum neutrophil counts were determined by H&E staining. Serum interleukin 8 (IL-8) levels were measured by enzyme-linked immunosorbent assay (ELISA). Genetic polymorphisms of ATG5 (-769T>C, -335G>A, and 8830C>T) and ATG7 (-100A>G and 25108G>C) were genotyped. The functional activities of ATG5 -769T>C and -335G>A variants were investigated by luciferase reporter assays. RESULTS: No associations of ATG5 and ATG7 polymorphisms with asthma susceptibility and severity were found. ATG5 -769T>C and -335G>A were in complete linkage disequilibrium. In the asthma group, GA/AA genotypes at ATG5 -335G>A were associated with higher neutrophil counts in sputum (p T associated with lower FEV1% predicted value (p G and 25108G>C were significantly associated with high serum levels of IL-8 (p < 0.05 for both variants). CONCLUSIONS: Genetic polymorphisms of ATG5 and ATG7 could contribute to neutrophilic airway inflammation in the pathogenesis of adult asthma.

Cellular response to altered autophagy activity in human fibroblast cells overexpressing Ha-RasV12 / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the effect of oncogenic Ras overexpression on autophagic activity in human fibroblast cells in vitro.</p><p><b>METHODS</b>BJ cells were transfected with H-RasV12 or control vector and treated with chloroquine, small interfering RNA (siRNA) for ATG7, or rapamycin. The cellular responses were analyzed by monitoring the parameters and biomarkers for cell growth, senescence and cell death.</p><p><b>RESULTS</b>In BJ cells overexpressing H-RasV12, chloroquine treatment resulted in more prominent cell senescence and a significantly increased cell death rate. Suppression of ATG7 mediated by siRNA also promoted cell senescence. Rapamycin treatment also caused an increased cell death rate but attenuated senescence in surviving cells. In control BJ cells, the cellular response to chloroquine included senescence and cell death, which occurred slowly. Rapamycin treatment and siRNA suppression of ATG7 had no obvious effect on control BJ cells.</p><p><b>CONCLUSION</b>Stable cellular overexpression of oncogenic Ras causes tightly controlled suppression of the autophagic activity of human fibroblast cells, and such changes produce significant effect on cell senescence and survival.</p>