Alternative splicing (AS) serves as a fundamental regulatory mechanism in gene expression, contributing to proteomic diversity by generating an array of mRNA isoforms from precursor mRNA via distinct splice site combinations. In light of the limited therapeutic options currently available, the exploration of AS as a target for drug development is of paramount importance. This review offers an exhaustive analysis of the biological functions and underlying molecular mechanisms associated with various AS-induced splice variants, RNA-binding proteins, and cis-elements, highlighting their significance as clinical biomarkers. We place particular emphasis on the current therapeutic applications of AS in an array of lung diseases, including but not limited to lung cancer, cystic fibrosis, silicosis, acute respiratory distress syndrome, pneumonia, asthma, chronic obstructive pulmonary diseases, pulmonary arterial hypertension, and idiopathic pulmonary fibrosis. The review delves into the role of AS events in the diagnosis and treatment of lung diseases, focusing on the regulatory influence of splicing factors and RNA-binding proteins, while also enumerating the mutated components implicated in AS misregulation. Consequently, a comprehensive understanding of the intricate mechanisms governing these splicing events could potentially offer novel avenues for the development of splicing-targeted therapeutics and diagnostic tools for the prevention and treatment of lung diseases.

Idiopathic pulmonary fibrosis (IPF), a chronic interstitial lung disease, is characterized by aberrant wound healing, excessive scarring and the formation of myofibroblastic foci. Although the role of alternative splicing (AS) in the pathogenesis of organ fibrosis has garnered increasing attention, its specific contribution to pulmonary fibrosis remains incompletely understood. In this study, we identified an up-regulation of serine/arginine-rich splicing factor 7 (SRSF7) in lung fibroblasts derived from IPF patients and a bleomycin (BLM)-induced mouse model, and further characterized its functional role in both human fetal lung fibroblasts and mice. We demonstrated that enhanced expression of Srsf7 in mice spontaneously induced alveolar collagen accumulation. Mechanistically, we investigated alternative splicing events and revealed that SRSF7 modulates the alternative splicing of pyruvate kinase (PKM), leading to metabolic dysregulation and fibroblast activation. In vivo studies showed that fibroblast-specific knockout of Srsf7 in conditional knockout mice conferred resistance to bleomycin-induced pulmonary fibrosis. Importantly, through drug screening, we identified lomitapide as a novel modulator of SRSF7, which effectively mitigated experimental pulmonary fibrosis. Collectively, our findings elucidate a molecular pathway by which SRSF7 drives fibroblast metabolic dysregulation and propose a potential therapeutic strategy for pulmonary fibrosis.

Diabetic mellitus (DM) is a common degenerative chronic metabolic disease often accompanied by severe cardiovascular complications (DCCs) as major causes of death in diabetic patients with diabetic cardiomyopathy (DCM) as the most common DCC. The metabolic disturbance in DCM generates the conditions/substrates and inducers/triggers and activates the signaling molecules and death executioners leading to cardiomyocyte death which accelerates the development of DCM and the degeneration of DCM to heart failure. Various forms of programmed active cell death including apoptosis, pyroptosis, autophagic cell death, autosis, necroptosis, ferroptosis and entosis have been identified and characterized in many types of cardiac disease. Evidence has also been obtained for the presence of multiple forms of cell death in DCM. Most importantly, published animal experiments have demonstrated that suppression of cardiomyocyte death of any forms yields tremendous protective effects on DCM. Herein, we provide the most updated data on the subject of cell death in DCM, critical analysis of published results focusing on the pathophysiological roles of cell death, and pertinent perspectives of future studies.

Idiopathic pulmonary fibrosis (IPF) is a progressive disease with unknown etiology and limited therapeutic options. Activation of fibroblasts is a prominent feature of pulmonary fibrosis. Here we report that lncRNA DACH1 (dachshund homolog 1) is downregulated in the lungs of IPF patients and in an experimental mouse model of lung fibrosis. LncDACH1 knockout mice develop spontaneous pulmonary fibrosis, whereas overexpression of LncDACH1 attenuated TGF-β1-induced aberrant activation, collagen deposition and differentiation of mouse lung fibroblasts. Similarly, forced expression of LncDACH1 not only prevented bleomycin (BLM)-induced lung fibrosis, but also reversed established lung fibrosis in a BLM model. Mechanistically, LncDACH1 binding to the serine/arginine-rich splicing factor 1 (SRSF1) protein decreases its activity and inhibits the accumulation of Ctnnb1. Enhanced expression of SRSF1 blocked the anti-fibrotic effect of LncDACH1 in lung fibroblasts. Furthermore, loss of LncDACH1 promoted proliferation, differentiation, and extracellular matrix (ECM) deposition in mouse lung fibroblasts, whereas such effects were abolished by silencing of Ctnnb1. In addition, a conserved fragment of LncDACH1 alleviated hyperproliferation, ECM deposition and differentiation of MRC-5 cells driven by TGF-β1. Collectively, LncDACH1 inhibits lung fibrosis by interacting with SRSF1 to suppress CTNNB1 accumulation, suggesting that LncDACH1 might be a potential therapeutic target for pulmonary fibrosis.

Aim To examine the role and uderlying mechanisms of Lin28 /let-7d axis in the proliferation of lung fibrobalsts and fibroblasts-into-myfibroblasts tran-sition,and provide novel strategy for the treatment of idiopathic pulmonary fibrosis (IPF).Methods We induced experimental lung fibrosis in mice by intratra-cheally injection of bleomycin (BLM).Ang Ⅱ and TGF-β1 were used to induce fibrogenesis in cultured MRC-5 cells;qRT-PCR and Western blot were applied to determine the changes of Lin28B,collagen 1 α1 and collagen 3α1 ;MTT assay,Edu satining and immun-ofluoresence were used to examine the cell viability, proliferation and fibroblasts-into-myofibroblasts transi-tion in MRC-5 cells.Results Lin28B was increased in the lung of mice with experimental lung fibrosis and in MRC-5 cells treated with AngⅡ or TGF-β1 .Moreo-ver,Lin28B enhanced collagen deposition via inhibi-ting expression of let-7d,which maybe contribute to the progression of IPF.In addition,further studies showed that Lin28B promoted proliferation and fibro-blasts-into-myofibroblasts in MRC-5 cells.Conclusion Lin28B /let-7d axis contributes to fibrogenesis via promotes fibroblasts-into-myofibroblasts transition, which may provide novel approaches for lung fibrosis treatment.

MicroRNAs (miRNAs) are a class of phylogenetically conserved, non-coding short RNAs, 19-22 nt in length which suppress protein expression through base-pairing with the 3'-untranslated region of target mRNAs. miRNAs have been found to participate in cell proliferation, differentiation and apoptosis. Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and high lethality fibrotic lung disease for which currently there is no effective treatment. Some miRNAs have been reported to be involved in the pathogenesis of pulmonary fibrosis. In this review, we discuss the role of miRNAs in the pathogenesis, diagnosis and treatment of IPF.