Effect of fatty acid binding protein 4 on the apoptosis of podocytes in mice with hyperhomocysteinemia / 医学研究生学报

ABSTRACT

Objective　To investigate the role of fatty acid binding protein 4 (FABP4) in the apoptosis of mouse podocytes induced by hyperhomocysteinemia (HHcy).　Methods　Nine wild male C57BL/6J mice (Cbs+/+) and nine C57BL/6J male mice with cystathionine beta synthase gene knockout heterozygote (Cbs+/-) were used as the control group and HHcy model group, respectively. All mice were fed with 2% high methionine diet for 8 weeks to replicate the HHcy model. The ultrastructure of glomerular podocytes was observed by transmission electron microscopy. Glomerular podocytes were cultured in vitro and divided into blank control group (Control group) podocytes treated with Hcy concentration of 0 μmol•L-1 for 48 hours. The podocytes of homocysteine group (Hcy group) were treated with Hcy concentration of 80 μmol•L-1 for 48 hours. Podocytes were infected with GFP-labeled adenovirus (Ad-GFP group) and FABP4 overexpression adenovirus (Ad-FABP4 group), respectively. Podocytes were treated with Hcy and FABP4 adenovirus, named as Hcy+Ad-FABP4 group. The expression of FABP4 was detected by qRT-PCR and Western blot. The changes of apoptosis-related proteins Bax, Bcl-2 and Caspase-12 were analyzed by Western blot. The apoptosis rate of cells was measured by flow cytometry.　Results　Compared with the control group, the podocyte injury was aggravated and accompanied by the increasing number of apoptotic cells in the kidney tissues of model group mice. At the same time, the expression of FABP4 mRNA (3.20±0.42) and protein (4.98±1.12) in model group were higher than those in control group (2.09±0.13, 3.04±0.11)(P0.05); the mRNA expression levels (4.59±0.28) and protein expression (10.07±0.82) of FABP4 in Ad-FABP4 group were higher than those in Ad-GFP group (P<0.05). Bax/Bcl-2 value (3.15±0.65) and Caspase-12 protein expression (4.30±0.89) in Hcy group were higher than those in control group (2.19±0.10, 3.19±0.47) (P<0.05). The Bax/Bcl-2 values (5.42±0.55) and Caspase-12 protein expression (7.87±1.27) in the Hcy+Ad-FABP4 group were significantly higher than those in the Hcy+Ad-GFP group (3.19±0.47, 4.34±0.64) (P<0.05).　FABP4 plays an important role in the apoptosis of mouse podocytes induced by HHcy. Flow cytometry analysis showed that the total apoptotic rate of Hcy group was (10.85±1.25) higher than that of control group (3.77±0.12) (P<0.05). Hcy + Ad-FABP4 group (15.72±1.60) was higher than that of Hcy+Ad-GFP group (11.22±0.43) (P< 0.05).　Conclusion　FABP4 promotes the apoptosis of podocytes in mice treated with HHcy.