ABSTRACT
Background The pathogenesis and development of cataract is associated with oxidative stress-induced apoptosis of human lens epithelial cells(LECs).BH3-only protein is a factor that can initiate apoptosis,and thus the apoptotic process is probably related to the activation of the c-Jun N-terminal kinase(JNK).However,the relationship between oxidative stress-induced apoptosis of human LECs and the JNK pathway remains to be illuminated.Objective This study was to investigate the effects of the JNK/c-Jun pathway and its target gene,Bim (Bcl-2 interacting mediator of cell death)and PU M A(p53 up-regulated modulator of apoptosis),on oxidative stressinduced apoptosis of human LECs.Methods The human LECs cell line(HLEC-B3)was cultured and passaged in DMEM with 10％ fetal bovine serum in vitro.Confluent cells were incubated in 24 well plates and divided into 4 groups.Hydrogen peroxide(H2O2)(50 μmol/L)was used to treat the cells for 4,8 or 12 hours,and cells without H2O2 treatment served as the control group.Apoptosis was detected using Hoechst 33258 staining and quantified by counting the number of cells with pyknotic nuclei.In addition,confluent cells were seeded in 6 well plates,and Western blot and RT-PCR were used to detect the expression of the caspase-3,c-Jun,Bim and PUMA proteins and their mRNA in HLEC-B3,respectively.The JNK/c-Jun pathway inhibitors,CEP11004 or SP600125,were added into cultured media with H2O2,and cells treated with DMSO or H2O2 only served as negative and positive control groups.The expression of the p-JNK,JNK,p-c-Jun,c-Jun,Bim,PUMA proteins was detected by Western blot and apoptosis was assayed using Hoechst 33258 staining.200 pmoL/L of Bim or PUMA small interference RNA(siBim or siPUMA)fragments were transfected into the cells for 24 hours,respectively,and H2O2 was then used to treat the cells for 8 hours.The expression of the Bim and PUMA protein and their mRNA in the cells was detected by Western blot and RT-PCR,respectively.Results After H2O2 treatment in HLEC-B3 cells for 4,8,or 12 hours,the rates of apoptosis were 4.30％±1.15％,27.08％±0.74％ and 46.59％±0.91％,showing a significant difference among them (F=1909.433,P=0.000),and those of the 4,8,12 hour groups were significantly increased in comparison to the control group(P =0.049,0.000,0.000).Compared to untreated cells,the levels of expression of the JNK,Bim,PUMA proteins and their mRNA in HLEC-B3 cells were significantly elevated.After the addition of CEP11004 or SP600125,the expression of these protein and mRNA in HLEC-B3 cells in the presence of H2O2 was significantly weaker than that in the DMSO control group(P =0.000,0.000).After the tranfection of siBim or siPUMA,the apoptosis rates of the H2O2 treated groups were significantly higher than those in the Bim-/-or PIMA-/-group (P＜0.05).Conclusions H2O2 can activate the JNK/c-Jun pathway and up-regulate the expression of its target genes Bim and PUMA in human LECs in a time-dependent manner.Inhibiting the JNK/c-Jun pathway and interfering with the expression of Bim and PUMA can protect human LECs against oxidative stress-induced apoptosis.
ABSTRACT
Background Some aboard studies showed that polyatomic pathway play an important role in the microsvasculopathy of type 2 diabetes,and sorbitol dehydrogenase (SDH) gene is involved in the pathogenesis of diabetic retinopathy(DR).There is no relevant research at home up to now.Objective This study was to investigate the correlation of sorbitol dehydrogenase (SDH) G-888C gene polymorphism with diabetic retinopathy (DR) in type 2 diabetes mellitus.Methods The SDH genotypes were determined by polymerase chain reactionreaction fragment length polymorphism (PCR-RFLP) in 187 patients with diabetes and 123 normal contrels.Patients were divided into two groups depending on the presence or absence of DR(DR:n=118;NDR:n=69).The frequencies of SDH genotype and allele were assayed and compared among these groups.This study was approved by Ethic Committee of Guangdong General Hospital.Written informed consent was obtained from each individual prior to any relevant medical procedure.Results The disease course in the DR group was significantly longer than that in NDR group(t=2.070,P=0.042),and other clinical features in both groups were non-significant (all P>0.05).The genotype frequencies in the DR group,NDR group and normal control group were 24.6%,8.7% and 8.1%,respectively,and frequencies of the G allele were 42.4%,25.4% and 29.7%,showing statistically significant differences among these three groups.The GG genotype and G allele frequencies were significantly higher in the DR group than those in the NDR group and normal control group (GG:P=0.007,P=0.001;G:P=0.001,P=0.004).There were no significant differences in the frequencies of the GG genotype and G allele between the NDB group and normal control group ( P>0. 05) as well as the proliferative DR group and non-proliferative DR group (P>0.05).Conclusion SDH G-888C gene polymorphism is associated with the development of diabetic retinopathy in southern Chinese.
ABSTRACT
Costimulatory signals have become a hot field in immunological researches. As co-inhibitory molecules, programmed death-1 ( PD-1) and its ligands (PD-1/PD-L) have been demonstrated to play an important role in autoimmune disease, organ transplant rejection, microorganism infection, tumor immune escapes etc. . In recent years,some studies about PD-1/PD-L pathway in ophthalmology have been curried out and reported. Some changes were found in PD-1/PD-L pathway, such as ocular immunologic diseases, ocular infectious diseases, ocular tumors, immune privilege in ocular tissues and so on. Through the research on PD-1/PD-L pathway,we can further understand the pathogenesis of some ocular diseases and find new methods for their prevention and treatments. This article reviewed the recent advances in PD-1/PD-L pathway in ophthalmological physiopathology.