Respiratory Department, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China.
Respiratory Department, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning 121001, P.R. China.
Mol Med Rep. 2021 Sep;24(3). doi: 10.3892/mmr.2021.12258. Epub 2021 Jul 2.
Fibrosis of lung tissue can induce the occurrence and development of numerous types of lung disease. The expression levels of the long non‑coding RNA (lncRNA) HOXA distal transcript antisense RNA (HOTTIP) have been reported to be upregulated during the development of fibrosis in liver tissues, which subsequently activated hepatic stellate cells. However, whether the lncRNA HOTTIP participates in the occurrence and development of lung fibrosis remains unknown. The present study aimed to investigate the role of lncRNA HOTTIP in lung fibrosis and its potential mechanism. In the present study, A549 cells were stimulated with TGF‑β1 to induce lung fibrosis . A549 was transfected with short hairpin RNA‑HOTTP, overexpression‑polypyrimidine tract binding protein 1 (PTBP1), microRNA (miR)‑744‑5p mimic or miR‑744‑5p to regulate gene expression. Cell proliferation and migration were determined using 5'‑ethynl‑2'‑deoxyuridine and wound healing assays, respectively. The expression levels of α‑smooth muscle actin, collagen I, collagen III and fibronectin 1 were analyzed using western blotting. starBase was used to identify molecules that may interact with the lncRNA HOTTIP and dual luciferase reporter assays were used to validate the findings. Moreover, an lung fibrosis model was established by bleomycin induction in mice. Histological injury was observed using hematoxylin and eosin and masson staining. The results of the present study revealed that the proliferation and migration of A549 cells were both suppressed following the knockdown of HOTTIP. The lncRNA HOTTIP was found to target and downregulate the expression levels of miR‑744‑5p. The overexpression of miR‑744‑5p inhibited the proliferation and migration of A549 cells. Furthermore, miR‑744‑5p targeted and downregulated the expression levels of PTBP1. It was subsequently demonstrated that the overexpression of PTBP1 rescued miR‑744‑5p‑induced suppression of the proliferation and migration of A549 cells. The knockdown of lncRNA HOTTIP expression also relieved the fibrosis of the lung tissues of mice. In conclusion, the results of the present study suggested that the lncRNA HOTTIP may promote the fibrosis of lung tissues by downregulating the expression levels of miR‑744‑5p and upregulating the expression levels of PTBP1.
肺组织纤维化可诱导多种类型的肺部疾病的发生和发展。据报道，在肝组织纤维化的发展过程中，长链非编码 RNA（lncRNA）HOXA 远端转录反义 RNA（HOTTIP）的表达水平上调，随后激活肝星状细胞。然而，lncRNA HOTTIP 是否参与肺纤维化的发生和发展尚不清楚。本研究旨在探讨 lncRNA HOTTIP 在肺纤维化中的作用及其潜在机制。在本研究中，用 TGF-β1 刺激 A549 细胞诱导肺纤维化。用短发夹 RNA-HOTTIP、过表达多嘧啶 tract 结合蛋白 1（PTBP1）、miR-744-5p 模拟物或 miR-744-5p 转染 A549，以调节基因表达。分别用 5'-乙氧嘧啶-2'-脱氧尿苷和划痕愈合实验测定细胞增殖和迁移。用 Western blot 分析α-平滑肌肌动蛋白、胶原 I、胶原 III 和纤维连接蛋白 1 的表达水平。使用 starBase 识别可能与 lncRNA HOTTIP 相互作用的分子，并使用双荧光素酶报告基因检测实验验证发现。此外，通过博来霉素诱导建立小鼠肺纤维化模型。用苏木精和伊红及 Masson 染色观察组织学损伤。本研究结果表明，HOTTIP 敲低后 A549 细胞的增殖和迁移均受到抑制。lncRNA HOTTIP 被发现可靶向并下调 miR-744-5p 的表达水平。miR-744-5p 的过表达抑制了 A549 细胞的增殖和迁移。此外，miR-744-5p 靶向并下调了 PTBP1 的表达水平。随后证实，PTBP1 的过表达可挽救 miR-744-5p 诱导的 A549 细胞增殖和迁移抑制。lncRNA HOTTIP 表达的敲低也缓解了小鼠肺组织的纤维化。综上所述，本研究结果表明，lncRNA HOTTIP 可能通过下调 miR-744-5p 的表达水平和上调 PTBP1 的表达水平促进肺组织纤维化。
