Dynamic changes between osteopontin and collagen I expression in viral myocarditis mice / 中南大学学报(医学版)

OBJECTIVE@#To study the mechanism of osteopontin (OPN) in viral myocarditis by observing the expression of OPN and collagen I (Col I) in mice myocardium.@*METHODS@#The viral myocarditis models were achieved by infection with myocarditic coxsackievirus B3 (CVB3). The myocardium of mice was stained by HE and Masson staining, and the pathological scores and the collagen volume fraction (CVF )of myocardium were tabulated. The expression of Col I mRNA was measured by RT-PCR. The expression of OPN was detected by RT-PCR and ELISA.@*RESULTS@#The histopathological examination revealed a prevalence of myocardial cell necrosis and obvious inflammation changes at the 7th day post-infection. Subsequently the inflammatory lesions were gradually absorbed. At the 28th day, the inflammatory cells had almost disappeared and obvious fibrosis occurred. The pathological scores and the expression of OPN mRNA were higher than those of the control group (P<0.05), and reached the highest level at the 7th day (P<0.05). From the 14th day, these parameters decreased,reflected also in the ELISA results. At the 7th day and the 14th day, the Col I expression was similar to that of control. Col I expression at the 21th and 28th days was higher than those of the control (P<0.05), and correlated positively to the CVF results.@*CONCLUSION@#The OPN mRNA expression increased in acute stage of VMC, and higher than that of the control group when in recovery stage, suggesting that OPN might be related to the inflammatory response in acute stage of, and promote the collagen synthesis of recovery stage.

Nucleotide bias of DCL and AGO in plant anti-virus gene silencing

Plant Dicer-like (DCL) and Argonaute (AGO) are the key enzymes involved in anti-virus post-transcriptional gene silencing (AV-PTGS). Here we show that AV-PTGS exhibited nucleotide preference by calculating a relative AV-PTGS efficiency on processing viral RNA substrates. In comparison with genome sequences of dicot-infecting Turnip mosaic virus (TuMV) and monocot-infecting Cocksfoot streak virus (CSV), viral-derived small interfering RNAs (vsiRNAs) displayed positive correlations between AV-PTGS efficiency and G+C content (GC%). Further investigations on nucleotide contents revealed that the vsiRNA populations had G-biases. This finding was further supported by our analyses of previously reported vsiRNA populations in diverse plant-virus associations, and AGO associated Arabidopsis endogenous siRNA populations, indicating that plant AGOs operated with G-preference. We further propose a hypothesis that AV-PTGS imposes selection pressure(s) on the evolution of plant viruses. This hypothesis was supported when potyvirus genomes were analysed for evidence of GC elimination, suggesting that plant virus evolution to have low GC% genomes would have a unique function, which is to reduce the host AV-PTGS attack during infections.