Effects of tetrandrine on phenotypic modulation of vascular smooth muscle cells and expression of p38 MAPK as well as MKP-1 after intimal injury of rabbit carotid arteries

Objective： To study the effects of tetrandrine （Tet） on phenotypic modulation of vascular smooth muscle cells （VSMCs） and expression of p38 mitogen-activated protein kinase （p38MAPK） as well as mitogen-activated protein kinase phosphatase-1 （MKP-1） after vascular intimal injury. Methods： HE staining was used to analyze vascular morphology of sham-injured group, injured group and Tet-treated group at day 28. lmmunohistochemistry, Western blot and RT-PCR were respectively used to detect the expression change of smooth muscle a-actin （SMa-actin）, proliferation cell nuclear antigen （PCNA）, p38MAPK and MKP-1 of injured group and Tet group at days 7, 14 and 28 after balloon injury. Results： ① All layers of vascular wall in sham-injured group were intact at day 28. The neointimal area was significantly increased and the lumen area notably decreased in injured group at day 28. The neointimal proliferation in Tet treated group was less than that in injured group, and the lumen area of Tet group was significantly increased than that of injured group at day 28. ②Compared with the injured group, the expression of SMa-actin, PCNA, p38MAPK and MKP-1 of vascular wall in Tet group was no difference, and the neointimal proliferation condition was also basically as same as injured group at day 7 after injury. The expression of PCNA and p38MAKP in Tet group was obviously lower than that in injured group, and the expression of MKP-1 in Tet group was obviously higher than that in injured group at days 14 and 28 after injury. The expression of SMa-actin in Tet group was slightly higher than that in injured group at days 14 and 28 after injury. Conclusions： Tet could reduce neointimal proliferation by inhibiting VSMCs phenotypic modulation and p38MAPK signaling transduction pathway as well as its down regulation.

Let-7a gene knockdown protects against cerebral ischemia/reperfusion injury

The micro RNA（mi RNA） let-7 was one of the first mi RNAs to be discovered, and is highly conserved and widely expressed among species. let-7 expression increases in brain tissue after cerebral ischemia/reperfusion injury; however, no studies have reported let-7 effects on nerve injury after cerebral ischemia/reperfusion injury. To investigate the effects of let-7 gene knockdown on cerebral ischemia/reperfusion injury, we established a rat model of cerebral ischemia/reperfusion injury. Quantitative reverse transcription-polymerase chain reaction demonstrated that 12 hours after cerebral ischemia/reperfusion injury, let-7 expression was up-regulated, peaked at 24 hours, and was still higher than that in control rats after 72 hours. Let-7 gene knockdown in rats suppressed microglial activation and inflammatory factor release, reduced neuronal apoptosis and infarct volume in brain tissue after cerebral ischemia/reperfusion injury. Western blot assays and luciferase assays revealed that mitogen-activated protein kinase phosphatase-1（MKP1） is a direct target of let-7. Let-7 enhanced phosphorylated p38 mitogen-activated protein kinase（MAPK） and c-Jun N-terminal kinase（JNK） expression by down-regulating MKP1. These findings suggest that knockdown of let-7 inhibited the activation of p38 MAPK and JNK signaling pathways by up-regulating MKP1 expression, reduced apoptosis and the inflammatory reaction, and exerted a neuroprotective effect following cerebral ischemia/reperfusion injury.

Effects of Glucocorticoid?Induced Transcript 1 Gene Deficiency on Glucocorticoid Activation in Asthmatic Mice

Background: Glucocorticoid (GC) is the first?line therapy for asthma, but some asthmatics are insensitive to it. Glucocorticoid?induced transcript 1 gene (GLCCI1) is reported to be associated with GCs efficiency in asthmatics, while its exact mechanism remains unknown. Methods: A total of 30 asthmatic patients received fluticasone propionate for 12 weeks. Forced expiratory volume in 1 s (FEV1) and GLCCI1 expression were detected. Asthma model was constructed in wild?type and GLCCI1 knockout (GLCCI1?/?) mice. Glucocorticoid receptor (GR) and mitogen?activated protein kinase phosphatase 1 (MKP?1) expression were detected by polymerase chain reaction and Western blotting (WB). The phosphorylation of p38 mitogen?activated protein kinase (MAPK) was also detected by WB. Results: In asthmatic patients, the change of FEV1 was well positively correlated with change of GLCCI1 expression (r = 0.430, P = 0.022). In animal experiment, GR and MKP?1 mRNA levels were significantly decreased in asthmatic mice than in control mice (wild?type: GR: 0.769 vs. 1.000, P = 0.022; MKP?1: 0.493 vs. 1.000, P < 0.001. GLCCI1?/?: GR: 0.629 vs. 1.645, P < 0.001; MKP?1: 0.377 vs. 2.146, P < 0.001). Hydroprednisone treatment significantly increased GR and MKP?1 mRNA expression levels than in asthmatic groups; however, GLCCI1?/?.asthmatic mice had less improvement (wild?type: GR: 1.517 vs. 0.769, P = 0.023; MKP?1: 1.036 vs. 0.493, P = 0.003. GLCCI1?/?: GR: 0.846 vs. 0.629, P = 0.116; MKP?1: 0.475 vs. 0.377, P = 0.388). GLCCI1?/? asthmatic mice had more obvious phosphorylation of p38 MAPK than wild?type asthmatic mice (9.060 vs. 3.484, P < 0.001). It was still higher even though after hydroprednisone treatment (6.440 vs. 2.630, P < 0.001). Conclusions: GLCCI1 deficiency in asthmatic mice inhibits the activation of GR and MKP?1 and leads to more obvious phosphorylation of p38 MAPK, leading to a decremental sensitivity to GCs.