ABSTRACT
Objective To explore the effect of overexpression of retinoic acid receptor α(RARα)on epithelial-to-mesenchymal transition(EMT)induced by hypoxia in renal tubular epithelial cells(NRK-52E).Methods The RARα lentivirus vector and negative control lentivirus vector were synthetised.The NRK-52E cells were divided into 4 groups:the normal control group,the hypoxia model group,the transfection group and the negative control group.Puro-mycin(2 mg/L)was added in transfection group and negative control group for screening after gene interference for 72 h.Then the 2 groups were subjected to hypoxia/reoxygenation,but the normal control group had no treatment. The change of cellular morphology was observed by using light microscope;the mRNA and protein expressions of RARα, E-cadherin,α -smooth muscle actin(α-SMA)in NRK-52E cells were detected by adopting reverse transcription-polymerase chain reaction(RT-PCR)and Western blot after hypoxia for 48 h.Results (1)Light microscope re-vealed that cells in both hypoxia model group and negative control group cells became atrophic and elongated,which were consistent with the morphology of myofibroblasts.But cells in transfection group cells were cubic,forming an epi-thelial monolayer.(2)Compared with the normal control group,the mRNA and protein expressions of RARα and E-cadherin in hypoxia model group were dramatically reduced(mRNA:0.58 ± 0.12 vs.1.00 ± 0.00,0.11 ± 0.00 vs. 1.00 ± 0.00,t= -0.63,767.30,all P<0.05;protein:0.63 ± 0.12 vs.1.62 ± 0.16,0.44 ± 0.22 vs.1.27 ± 0.08,t=8.61,6.19,all P<0.05),but the mRNA and protein expressions of α-SMA were higher(3.47 ± 0.83 vs.1.00 ± 0.00,1.39 ± 0.16 vs.0.64 ± 0.10,t= -5.01,-6.91,all P<0.05).(3)The mRNA and protein expressions of RARα and E-cadherin in the transfection group were significantly increased,compared with hypoxia model group(mRNA:4.69 ± 1.34 vs.0.58 ± 0.12,0.23 ± 0.00 vs.0.11 ± 0.00,q=9.13,25.48,all P<0.05;protein:1.39 ± 0.19 vs. 0.63 ± 0.12,0.87 ± 0.09 vs.0.44 ± 0.22,q=7.92,4.30,all P<0.05)and negative control group(mRNA:4.69 ± 1.34 vs.0.55 ± 0.21,0.23 ± 0.00 vs.0.12 ± 0.01,q=9.20,23.35,all P<0.05;protein:1.39 ± 0.19 vs.0.65 ±0.18,0.87 ± 0.09 vs.0.39 ± 0.21,q=7.71,4.80,all P<0.05).Conversely,the mRNA and protein levels of α-SMA were obviously lower in transfection group(1.52 ± 0.34 vs.3.47 ± 0.83,4.05 ± 0.81,0.82 ± 0.13 vs.1.39 ± 0.10,1.17 ± 0.10,q=4.88,6.33,7.50,4.61,all P<0.05).The difference in mRNA and protein expressions of RARα,E-cadherin,α-SMA between the hypoxia group and the negative control group had no statistical significance (all P>0.05).Conclusion Overexpression of RARα could alleviate EMT of renal tubular epithelial cells induced by hypoxia.
ABSTRACT
Objective To explore the role of c-Jun N-terminal protein kinase(JNK)pathway in renal tubular epithelial cells(RTEC)transdifferentiation by detecting the expression of JNK pathway in the injury of hypoxic RTEC. Methods In vitro cultured rat RTEC were randomly divided into four groups of normal control, hypoxia,inhibitors,dimethyl sulfoxide(DMSO). The groups of hypoxia,inhibitor and DMSO were placed into a vacuum tank to establish hypoxia model. The cells were harvested 6,12 and 24 h after hypoxia started. RT-PCR and Western blot test were used to detect the mRNA expressions of alpha smooth muscle actin(α- SMA)and protein expressions of JNK,pJNK and alpha SMA,respectively,in all the groups. Results Hypoxia induced significantly increased expressions of α-SMA mRNA and proteins,and JNK and pJNK proteins as well in RTEC (all P<0.05).After addition of inhibitors,the expression of α-SMA mRNA and proteins,the protein expression of pJNK in RTEC were significantly decreased(all P < 0.05)and the expression of JNK protein was significantly increased(P < 0.05). There was no significant difference in the expressions of JNK,pJNK,α-SMA in RTECs between hypoxia group and DMSO group(all P>0.05).There was a significant positive correlation between pJNK protein and α-SMA protein expression(P < 0.01). Conclusion In hypoxic RETC injury in rats,JNK pathway may be involved in the RTEC phenotype transdifferentiation.