Inhibitory effect of caveolin-1 on endoplasmic reticulum stress-induced apoptosis in macrophages via p38 MAPK pathway / 生理学报

Endoplasmic reticulum (ER) stress occurs in macrophage-rich areas of advanced atherosclerotic lesions and contributes to macrophage apoptosis and subsequent plaque necrosis. The purpose of the present study was to investigate the effects of caveolin-1 (Cav-1) on ER stress-induced apoptosis in cultured macrophages and the underlying mechanisms. RAW264.7 cells were incubated with thapsigargin (TG) to establish ER stress model. And Cav-1 expression was detected by Western blot. After being pretreated with filipin(III), a caveolae inhibitor, RAW264.7 cells were assayed with flow cytometry and confocal laser scanning microscopy to detect cell apoptosis. Moreover, p38 mitogen-activated protein kinase (MAPK) phosphorylation and C/EBP homologous protein (CHOP) expression were detected with Western blot. The results showed that Cav-1 expression was markedly increased at early stage of TG treatment (P < 0.05) and then decreased with prolonged or high dose TG treatments. The increasing of Cav-1 expression induced by TG in RAW264.7 cells was abolished under inhibition of caveolae by filipin(III) (P < 0.05). The effect of TG on apoptosis of RAW264.7 cells was further augmented after pretreatment with filipin(III) (P < 0.05). Western blotting showed that MAPK phosphorylation induced by TG was inhibited by filipin(III) in RAW264.7 cells (P < 0.05), whereas CHOP remained unchanged (P > 0.05). These results suggest that Cav-1 may play a critical role in suppressing ER stress-induced macrophages apoptosis in vitro, and one of the mechanisms may be correlated with the activation of p38 MAPK prosurvival pathway.

Identification and function of the growth hormone gene in Rongjiang pig of China / 生理学报

Growth of animal is largely regulated by growth hormone (GH). In this study, the GH gene was isolated and cloned from the genomic DNA library from Rongjiang pig, a Chinese local swine, using polymerase chain reaction technique. The complete nucleotide sequence of a 1.903 kb genomic fragment containing Rongjiang swine GH gene has been determined. The GH gene contained five exons and four introns similar to the GH genes of other mammalians and exhibited 97%~99% identity to the GH genes of the four western meat-type breeds and nine Chinese local pigs. Polymorphism of GH genes was analyzed by using the restriction enzymes Dde I, Nar I and BsmN I in four western meat-type breeds and ten Chinese local pigs. Five polymorphic restriction sites, with Dde I at the base 622 (G/A) in exon 2 and 274 (T/C) in 5o-flank, with Nar I at 631 (G/A) in exon 2, and with BsmN I at the base 841 (T/C) in intron 2 and 1358 (A/G) in exon 4, were identified. The polymorphic restriction site at 1358 (A/G) leaded to the GH mature protein of Rongjiang pig differing from that of four western meat-type breeds and eight Chinese local breeds at the residue Val108 substituted by Ile108. According to the crystal structure of human GH mature protein, this Ile108 substitution might result in a lower affinity of GH for its receptor in Rongjiang breed.