ABSTRACT
Objective To investigate the role and underlying mechanism of cathepsin B in myocar-dial injury in mice with diabetic cardiomyopathy(DCM).Methods Twenty 8-week-old male SPF C57BL/6 mice were randomly divided into wild-type(WT)group and WT DCM group,with 10 mice in each group.Another 20 8-week-old male SPF-grade mice with cathepsin B knockout(KO)were randomly and equally assigned to KO group and KO DCM group.HE staining was used to observe morphological changes,Prussian blue staining was employed to detect iron deposition,while immunohistochemical staining with 4-hydroxynonenal(4-HNE)was used to assess lipid peroxidation level in the myocardial tissues.Western blotting was performed to detect the expression of heme oxygenase-1(HO-1),superoxide dismutase 2(SOD2),and nuclear factor E2-related factor 2(Nrf2),while RT-PCR was applied to evaluate the expressions of Nrf-2,HO-1,and phospholipid hydroperoxide glutathione peroxidase 4(GPX4).Results Compared to the WT DCM group,the KO DCM group presented improved cell arrangement in cardiac tissues and sig-nificant reduction in inflammatory cell infiltration.Furthermore,the KO DCM group displayed a significant decrease in iron deposition compared to the WT DCM group.Additionally,the KO DCM group exhibited a significant reduction in 4-HNE expression compared to the WT DCM group.The protein levels of Nrf2,SOD2,and HO-1 were significant increased in the KO DCM group than the WT DCM group(0.68±0.21 vs 0.39±0.13,0.59±0.10 vs 0.28±0.09,1.03±0.10 vs 0.48±0.04,P＜0.05).Moreover,elevated mRNA levels of GPX4,Nrf2 and HO-1 were also observed in the KO DCM group than the WT DCM group(0.65±0.09 vs 0.40±0.10,0.61±0.11 vs 0.34±0.11,0.62±0.12 vs 0.39±0.09,P＜0.05).Conclusion Cathepsin B exacerbates myocardial injury in DCM mice through ferroptosis.
ABSTRACT
OBJECTIVE@#To construct a HIV-1 gp120 transgenic mouse model (gp120) with 7 nicotinic acetylcholine receptor (7nAChR) gene knockout.@*METHODS@#The 7nAChR gene knockout mice (7R) were crossed with HIV-1gp120 transgenic mice (gp120) to generate F1 generation mice. We selected the F1 mice with the genotype of 7R/gp120 to mate to obtain the F2 mice. The genotypes of the F3 mice were identified by PCR, and the protein expressions in the double transgenic animal model was analyzed by immunohistochemistry. BV2 cells were treated with gp120 protein and 7nAChR inhibitor, and the expressions of IL-1β and TNF- were detected using ELISA.@*RESULTS@#The results of PCR showed the bands of the expected size in F3 mice. Two F3 mice with successful double gene editing (7R/gp120) were obtained, and immunohistochemistry showed that the brain tissue of the mice did not express 7 nAChR but with high gp120 protein expression. In the cell experiment, treatment with gp120 promoted the secretion of IL-1β and TNF- in BV2 cells, while inhibition of 7nAChR significantly decreased the expression of IL-1β and TNF- ( < 0.001).@*CONCLUSIONS@#By mating gp120 Tg mice with 7R mice, we obtained gp120 transgenic mice with 7nAChR gene deletion, which serve as a new animal model for exploring the role of 7nAChR in gp120-induced neurotoxicity.