Signal molecule 3-oxo-C12-HSL of Pseudomonas aeruginosa promotes autophagy of mouse alveolar macrophages MH-S cells / 基础医学与临床

Objective To investigate the effect of 3-oxo-C12-HSL on autophagy in mouse alveolar macrophages MH-S cells. Methods MH-S cells were treated with culture supernatants of the mutant and wild type Pseudomonas aeruginosa(PA) strains of LasI gene(3-oxo-C12-HSL synthetic gene) and chemically synthesized 3-oxo-C12-HSL signaling molecules. GFP puncta was observed by laser confocal fluorescence microscopy and the ratio of LC3Ⅱ/LC3Ⅰ was detected by Western blot to detect the formation of autophagic.Autophagic flux was also detected by mo-nitoring the degradation of p62 and the change of chloroquine to LC3Ⅱ/LC3Ⅰratio. Results The supernatant of the culture medium of the wild type PA strain increased the GFP puncta of the MH-S cells(P<0.05) and the ra-tio of LC3Ⅱ/LC3Ⅰ(P<0.01),The mutant PA strain of LasI gene could not cause the above changes related to autophagy. The chemically synthesized 3-oxo-C12-HSL signal molecules could increase the number of autophagic bodies and the expression of LC3Ⅱ (P<0.01). Autophagic substrate p62 was degraded by 3-oxo-C12-HSL. Chloroquine, a lysosomal inhibitor, enhanced LC3Ⅱaccumulation caused by 3-oxo-C12-HSL (P<0.05,P<0.01).Conclusions 3-oxo-C12-HSL increases the level of autophagy in MH-S cells.

HSF1 inhibits heat stress-induced apoptosis in Raw264.7 macrophages / 中南大学学报(医学版)

OBJECTIVE@#To observe the effect of heat shock factor 1 (HSF1) on heat stress-induced apoptosis in Raw264.7 macrophages.@*METHODS@#Raw264.7 cells transfected with pcDNA3.1 and pcDNA3.1-HSF1 were exposed to heat stress (42.5 degrees C +/- 0.5 degrees C) for 1 h and recovered at 37 degrees C for 6, 9, 12, and 24 h respectively. Flow cytometry (FCM), Hoechst 33258 staining and DNA ladder assays were performed to assess the apoptosis.@*RESULTS@#After heat stress, FCM showed that apoptotic cells were increased significantly and reached the peak at 9 h in Raw 264.7 cells transfected with pcDNA3.1, and were characterized with classical morphologic changes including apoptotic body and nuclear condensation. Agarose gel electrophoresis showed that "DNA ladder" could be observed clearly at 6, 9, and 12 h after the heat stress. But the overexpression of HSF1 could reduce the number of apoptotic cells and inhibit DNA fragmentation.@*CONCLUSION@#HSF1 can inhibit heat stress-induced apoptosis in Raw264.7 macrophages.

Characteristics and expression of Mip5, a novel gene associated with myocardial ischemia/reperfusion in rats / 中南大学学报(医学版)

OBJECTIVE@#To determine the characteristics of a novel gene Mip5 (GenBank accession number AY553870) and its expression under physiological and pathological conditions.@*METHODS@#The characteristics of Mip5 were analyzed by bioinformatic programs including BLAST, spidey, psort, ClustalW and so on. RT-PCR was performed to detect Mip5 expression.@*RESULTS@#Bioinformatic analysis showed that Mip5 gene lied in the 13th chromosome and contained 8 exons and 7 introns, its open reading frame contained 909 bp and its protein production was 302 amino acid residues including 6 kelth domains. Under normal conditions, MIP5 expressed abundantly in the heart, brain and kidney, but its expression could not be detected in the liver and muscle. Expression of Mip5 gene was increased significantly after ischemia-reperfusion compared with the sham groups, and reached its peak at 3 h and recovered at 12 h after the reperfusion. Conclusion Mip5 gene is a novel gene containing a putative open reading frame of 302 amino acids residues and may play an important role in rat cardiomyocytes suffering ischemia processing.

Effect of nucleolin down-regulation on the proliferation and apoptosis in C2C12 cells / 中南大学学报(医学版)

OBJECTIVE@#To clarify the effect of nucleolin on the proliferation and apoptosis in C2C12 cells.@*METHODS@#After inhibiting the expression of nucleolin using antisense oligonucleotides, the cellular proliferation was determined by MTT, and the apoptosis was detected by flow cytometry (FCM) assays and DNA ladder assays.@*RESULTS@#After being transfected with antisense oligonucleotides for 24 hours, Western blotting showed that the expression of nucleolin was repressed significantly. In cells treated with antisense oligonucleotides, the cellular proliferation was obviously inhibited; the apoptotic cell increased significantly; and the "DNA ladder" was clearly observed. But the sense and random oligonucleotides had no effect on the cellular proliferation and apoptosis.@*CONCLUSION@#The down-regulation of nucleolin can inhibit the cellular proliferation and initiate the apoptosis in C2C12cells.