ABSTRACT
Background The pathogenesis of beryllium-induced pulmonary fibrosis is unknown and there is no specific treatment for the disease as yet. MicroRNA (miRNA) may play a role in the process of beryllium-induced pulmonary fibrosis. Objective To construct a microRNA-21 (miR-21) interfering cell line, and to investigate the effect of miR-21 on beryllium sulfate (BeSO4)-induced fibrosis in human lung adenocarcinoma alveolar basal epithelial cells (A549 cells) and its potential mechanism. Methods The miR-21 target genes were predicted by the online database miRBase and verified by experiments using dual luciferase reporter gene. After transfecting A549 with miR-21interference lentivirus, puromycin was used to select a stable cell line. An in vitro model of pulmonary fibrosis was established using BeSO4 infecting A549 cells with a concentration of 10 μmol·L−1 and an exposure time of 48 h. Then the treated cells were divided into control group, model group, miR-21 interference group, and miR-21 interference control group. Real-time fluorescent quantitative PCR (RT-qPCR) was used to detect the relative expression level of miR-21 gene. Western blotting was used to detect the relative expression levels of TGF-β1/Smads pathway related proteins [Smad2, Smad3, p-Smad2, p-Smad3, Smad7, and transforming growth factor-β1 (TGF-β1)], myofibrosis cell marker α-smooth muscle actin (α-SMA), andextracellular matrix collagen-I (COL-I) and collagen-Ⅲ (COL-Ⅲ). Results The miRBase predicted that miR-21 had a binding site with Smad7, and the results of the dual luciferase reporter gene experiment showed that the target gene of miR-21 was Smad7. The construction of miR-21 interfered with A549 cell line was successful. Compared with the control group, the relative expression of miR-21 gene in the model group increased by 97.57%; the relative expression of Smad7 protein in the model group decreased by 15.48%; the relative protein expression of Smad2, Smad3, p-Smad2, p-Smad3, TGF-β1, α-SMA, COL-I, and COL-Ⅲ increased by 13.55%, 35.72%, 18.35%, 35.75%, 25.52%, 31.58%, 24.61%, and 11.66% respectively (P<0.05). Compared with the interference control group, the miR-21 gene expression level in the interference group decreased by 28.96%; the relative expression of Smad7 protein increased by 19.07%; the relative protein expression of Smad2, Smad3, p-Smad2, p-Smad3, TGF-β1, α-SMA, COL-I, and COL-Ⅲ decreased by 8.01%, 19.95%, 14.56%, 19.37%, 11.95%, 10.96%, 18.81%, and 31.36% repectively (P<0.05). There was no statistically significant difference in the gene abd protein expression levels of each gene between the model group and the interference control group (P>0.05). Conclusion In an in vitro model of pulmonary fibrosis induced by beryllium compounds, miR-21 may promote fibrosis by targeting Smad7 to regulate the TGF-β1/Smad signaling pathway.
ABSTRACT
Background Studies have shown that stress during pregnancy can affect the growth and development of fetuses and offspring, and this effect has sex differences, but the results are controversial, and there are few studies on the emotional damage of offspring of different sexes caused by stress during pregnancy. Objective This experiment is designed to observe the effect of chronic stress during pregnancy on emotional damage of offspring of different sexes. Methods Thirty-two SD female rats were randomly divided into a model group and a control group (16 rats in each group), 24 male rats were divided into a model mating group (n=16) and a control mating group (n=8). Each rat of the model group was reared in a single cage and received chronic unpredictable mild stress (CUMS) for 28 d, including hot water swimming for 5 min, cold water swimming for 5 min, tail pinching for 2 min, crowding for 24 h, moist bedding for 24 h, cage shaking for 30 min, and space restriction for 2 h. One stressor was administered daily and the same stressor did not repeat within 7 d. Blood was collected from the endocanthal vein of the two groups of female rats 1 d before and 1, 7, 14, 21, and 28 d after stress, the plasma was separated by centrifugation, and 131I radioimmunoassay was used to measure plasma corticosterone concentration. On postnatal day 21 (PND21), 16 offspring rats (half male and half male) were randomly selected from each group, their plasma corticosterone concentration was measured on PND28 and PND42, and their emotional damage was measured on PND42. Results The plasma corticosterone levels of dams in the model group on the 14th, 21th, and 28th days of stress [(394.02±97.40), (444.12±90.43), and (463.71±107.75) μg·L−1] were higher than those in the control group [(285.63±81.64), (341.78±48.39), and (320.42±84.76) μg·L−1] (all P< 0.05). On PND28 and PND42, the plasma corticosterone levels in the female model offspring group [(543.30±90.21) and (530.76±83.10) μg·L−1] were higher than those in the female control offspring group [(397.77±64.27) and (325.78±61.03) μg·L−1] (both P<0.05). In the sugar water preference test, the total fluid consumption [(10.74±1.28) mL], sugar water consumption [(5.50±1.30) mL], and 1% sucrose preference percentage [(20.36±3.41) %] in the female model offspring group were lower than those in the female control offspring group [(13.74±2.06) mL, (8.56±2.04) mL, and (62.11±8.05) %] (all P<0.05). In the open field test, the horizontal score, vertical score, and cleaning times of the male model offspring group were lower than those of the male control offspring group (all P<0.05). In the tail suspension test, the immobility time of the female and male model offspring groups [(126.95±39.88) and (70.24±28.98) s] was longer than the control offspring groups of the same sex [(54.30±24.99) and (38.63±18.91) s] (both P<0.05), and the duration of immobility time in the female model offspring group was longer (t=3.253, P=0.006). In the forced swimming test, the immobility time of the female model offspring group [(7.97±6.66) s] was longer than that of the female control offspring group [(1.85±2.12) s] (t=2.478, P=0.037). On PND42, the plasma corticosterone level of female offspring was negatively correlated with total fluid consumption, sugar water consumption, and 1% sucrose preference percentage (r=−0.621, r=−0.728, r=−0.699; P<0.05), and positively correlated with immobility time in the tail suspension test and immobility time in the forced swimming test (r=0.571, r=0.712; P<0.05), However, there was no correlation between plasma corticosterone and emotional indicators on PND42 in male offspring (P>0.05). Conclusion Chronic stress during pregnancy causes emotional damage to the offspring, and female offspring show depression-like behaviors.