ABSTRACT
Objective:To investigate the effects of down-regulation of FABP5 (fatty acid binding protein 5) on radiation damage of skin cells, and explore underlying mechanism.Methods:A lentiviral vector with down-regulated FABP5 was constructed to infect human immortalized keratinocytes (HaCaT) cells, and the transfection efficiency was examined. The HaCaT cells were divided into blank control group, FABP5 down-regulation group (FABP5), radiation group (IR), and FABP5 down-regulation combined with radiation group (FABP5+ IR). After 6 MV X-ray radiation, cell proliferation viability was measured by CCK-8 assay, cell migration was detected by scratch assay, apoptosis was analyzed by flow cytometry, radiosensitivity was evaluated by cloning formation assay, and the cellular protein expressions of PARP1, γ-H2AX, AKT and p-AKT were detected by Western blot.Results:FABP5 was successfully knocked-down in both RNA level ( t=25.14, P<0.05) and protein level ( t=20.06, P<0.05). The down-regulation of FABP5 decreased the abilities of cells proliferation ( t=3.55, 5.88, 3.18, P<0.05) and migration ( t=15.44, P<0.05), but increased cell resistance to irradiation with a radiosensitization ratio of 0.782. The apoptosis rate of FABP5+ IR group was significantly lower than IR group (22.05±6.71)% vs. (9.82±1.45)%, t=3.08, P<0.05. The protein levels of PARP1 and γ-H2AX in FABP5+ IR group were also lower than those in the IR group 0.04±0.04, 0.11±0.06, 0.26±0.11, 0.22±0.07, 0.21±0.10, 0.52±0.22, 0.57±0.06, 0.43±0.02( t=2.83, 3.07, 4.50, 5.33, P<0.05), while the protein level of p-Akt in FABP5+ IR group was higher than that in IR group ( t=-16.24—3.02, P<0.05). Conclusions:Down-regulation of FABP5 inhibited cell proliferation and migration, increased radioresistance, and reduced radiation-induced apoptosis and DNA damage of skin cells probably through PI3K/AKT signaling pathway.
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Background Silicosis is caused by long-term inhalation of large amounts of free silica (SiO2) particles, and exploring its mechanism can provide new directions for the treatment of silicosis fibrosis. Objective To investigate the expression and role of fatty acid binding protein 5 (FABP5) in a silica-induced silicosis model. Methods In combination with the results of single-cell transcriptome sequencing, the expression pattern of FABP5 in mouse alveolar epithelial cells was explored by bioinformatic analysis, and the distribution pattern of fabp5 was detected by spatial transcriptomics. An in vivo model of silicosis was established by intratracheal injection with SiO2 into mice and four groups were set up: normal saline (NS) 7 d group, NS 56 d group, SiO2 7 d group, and SiO2 56 d group. An in vitro model of silicosis was established in SiO2-treated mouse lung epithelial cell line (MLE-12). At the whole animal level, the marker of epithelial cells (E-Cad) and the protein level of FABP5 were detected by tissue immunofluorescence assay; in vitro, the changes of fabp5 mRNA expression and protein level in MLE-12. Results The results of single-cell transcriptome sequencing and spatial transcriptome sequencing showed that the mRNA expression of fabp5 was upregulated in type II alveolar epithelial cells in the focal area of silicosis in mice, accompanied by elevated tissue immunofluorescent protein levels, and there was co-localization of E-CAD. Meanwhile, SiO2 stimulation induced a 1.58-fold increase in fabp5 mRNA expression and a 2-fold increase in protein levels in MLE-12 cells, with significant differences (P<0.05). Conclusion The protein level of FABP5 is increased in alveolar epithelial cells in a pulmonary fibrosis model, suggesting that FABP5 may be involved in the pathological process of epithelial cells in pulmonary fibrosis.
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Objective:To explore the influence of microRNA (miRNA)-6751-3p expression on the proliferation and migration of gastric cancer cells and its molecular mechanism.Methods:Real-time quantitative polymerase chain reaction (qRT-PCR) was used to detect the expression level of miR-6751-3p in gastric cancer cell lines (MGC803, BGC823, SGC7901, HS-746T) and normal gastric mucosal epithelial cells (GES-1). The gastric cancer cell lines with the lowest expression level of miR-6751-3p were divided into control group and experimental group, and were transfected with miR-NC and miR-6751-3p mimics respectively. qRT-PCR detected the expression level of miR-6751-3p in the two groups of cells. CCK-8 method and scratch healing test were used to detect the proliferation and migration of miR-6751-3p overexpressing cells. The potential target genes of miR-6751-3p were predicted through Deepbase v2.0 and microRNA.org online websites, and the dual luciferase reporter gene experiment was used to verify. qRT-PCR and Western blot were used to detect the expression of target genes in miR-6751-3p overexpression cells.Results:Compared with normal gastric mucosal epithelial cells, the expression of miR-6751-3p was significantly down-regulated in gastric cancer cell lines ( P<0.05), and the cell line with the lowest expression level was MGC803 cells ( P<0.01). Compared with the control group, overexpression of miR-6751-3p can inhibit the proliferation ability ( P<0.05). The scratch healing rate of MGC803 cells in the control group and the experimental group were (65.14±5.65)% and (23.40±6.78)%, respectively. Compared with the control group, the scratch healing rate of MGC803 cells in the experimental group was significantly lower ( t=4.73, P<0.01). The online website predicts that the target gene of miR-6751-3p may be fatty acid binding protein 5 ( FABP5), and miR-6751-3p can complementally bind FABP5 messenger RNA (mRNA) ( t=4.01, P<0.01). Compared with the control group, overexpression of miR-6751-3p can inhibit the expression of FABP5 gene in MGC803 cells ( P<0.01). Conclusion:The expression of miR-6751-3p in gastric cancer cell lines is low, and the overexpression of miR-6751-3p can inhibit the proliferation and migration of gastric cancer MGC803 cells by down-regulating the FABP5 gene.
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AIM:To investigate the effect of recombinant lentiviral vector for RNA interference (RNAi) on the expression of fatty acid-binding protein 5 (FABP5) gene in hepatocellular carcinoma HepG2 cells and tumor formation in nude mice.METHODS:RNAi lentiviral vector was used in the experiment.Human hepatocellular carcinoma HepG2 cells were divided into 3 groups:the HepG2 cells in experimental group were transfected with the recombinant lentivirirus vector LV-shRNA-FABP5, the cells in negative control group were transfected with a control lentiviral vector LV-shRNA-NC, and the cells in normal control group were without any treatment.The nude mice were randomly divided into 3 groups.The growth of the transplanted tumor cells in the nude mice was observed.The tumor growth curve, volume and weight were de-termined 4 weeks after the cell inoculation.The expression of FABP5 was detected by real-time PCR, Western blot and im-munohistochemical staining.RESULTS:Transfection of the lentiviral vector FABP5-shRNA obviously reduced FABP5 ex-pression in the HepG2 cells.Tumor formation was all positive in the 3 groups of the nude mice inoculated with the tumor cells.Compared with normal control group and negative control group, the tumor growth slowed significantly in experimental group with smaller volume and weight.FABP5 expression in the transplanted tumor tissues was significantly down-regulated at mRNA and protein levels in experimental group as compared with normal control group and negative control group. CONCLUSION:RNAi-induced down-regulation of FABP5 effectively inhibits the growth of transplanted hepatocellular carcinoma, suggesting that FABP5 gene may be an effective target for gene therapy in treating liver cancer.