Objective Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease characterized by progressive dyspnea, with high morbidity and mortality globally. Tectochrysin, a flavonoid with several pharmacological activities, has not yet been explored for its anti-fibrotic effects. This study aims to investigate the role of tectochrysin in bleomycin (BLM)-induced IPF in mice, as well as its mechanism and target. Methods Intratracheal injection of BLM was employed to induce IPF in mice, and the protective effect of tectochrysin was evaluated through multiple experimental techniques. In vitro, TGF-β1-stimulated human embryonic lung fibroblasts (HELFs) was used to assess the anti-fibrotic activity of tectochrysin. Network pharmacology, bioinformatics, molecular docking, cellular thermal shift assay and drug affinity responsive target stability experiments were employed to explore the anti-fibrotic targets and mechanisms. Results In vivo, tectochrysin effectively mitigated BLM-induced extracellular matrix deposition, reduced the expression of fibrosis-related factors, and ameliorated lung injury. In vitro, tectochrysin dose-dependently inhibited TGF-β-induced α-SMA and collagen 1 expression, as well as the migration of HELFs. Notably, the inhibitory effect of tectochrysin on HELF activation and migration reached a level comparable to that of the positive control, pirfenidone, in this in vitro system. Further investigations revealed that tectochrysin directly bind to PI3K p85, forming hydrogen bonds with THR-369 and LYS-382 residues, thereby inhibiting the activation of the PI3K/AKT/mTOR signaling pathway. Conclusion Tectochrysin can alleviate BLM-induced IPF by targeting PI3K p85, thereby inhibiting the activation of the PI3K/AKT/mTOR signaling pathway. This study uncovers a previously unreported anti-fibrotic activity of tectochrysin, and highlight its potential as a candidate for the treatment of IPF.
Increased right ventricular afterload, persistent pulmonary vascular remodelling, and the development of right heart failure are the hallmarks of pulmonary hypertension (PH). In PAH, therapies targeting the prostacyclin, nitric oxide–cyclic guanosine monophosphate, and endothelin pathways improve clinical status and haemodynamics, although established vascular remodelling frequently remains incompletely reversible. This review summarises data suggesting that the residual remodelling load in PH is influenced by vascular ageing, specifically stress-induced premature senescence-like phenotypes in pulmonary vascular wall cells. Endothelial repair failure, pulmonary artery smooth muscle cell secretory amplification, extracellular matrix (ECM) stiffening, senescence-associated secretory phenotype signalling, and mechano-metabolic reprogramming are examined as interconnected processes that attenuate vascular plasticity and consolidate disease progression. Pharmacological strategies discussed include senolytic and senomorphic approaches, activin/TGF-β superfamily modulation exemplified by sotatercept, matrix- and mechanotransduction-directed interventions, and metabolic modulation. Finally, vascular ageing-informed PH studies are proposed to incorporate concordant endpoints that align molecular target engagement with pulmonary vascular mechanics, right ventricular–pulmonary arterial (RV–PA) coupling, right ventricular function, and safety outcomes.
Lung ischemia-reperfusion injury (LIRI) contributes substantially to primary graft dysfunction after lung transplantation and also occurs in other clinical settings involving transient interruption and restoration of pulmonary blood flow. O-linked beta-N-acetylglucosamine (O-GlcNAc) modification is rapidly altered by cellular stress, yet its role in acute pulmonary ischemia-reperfusion remains incompletely understood. We investigated this question using a murine model of transient left pulmonary hilar occlusion followed by reperfusion and an oxygen-glucose deprivation/reoxygenation (OGD/R) model in MLE-12 cells. O-GlcNAcylation was increased pharmacologically with the O-GlcNAcase inhibitor Thiamet G and reduced with the O-GlcNAc transferase inhibitor OSMI-4. Global O-GlcNAc levels, indices of tissue and cellular injury, and Caspase-1/GSDMD-related pyroptotic signaling were then examined. In both models, O-GlcNAcylation increased early after ischemic stress, whereas pyroptosisrelated changes became more pronounced as injury progressed. Thiamet G preserved MLE-12 cell viability, reduced LDH release, and lessened histopathological damage, pulmonary edema, and alveolar-capillary protein leakage in vivo. These effects were accompanied by lower Caspase-1 activation, reduced GSDMD cleavage, and fewer Caspase-1/PI double-positive cells. OSMI-4 produced the opposite pattern, with greater tissue and cellular injury and stronger pyroptosis-related signaling. The protective effect of Thiamet G was also weakened when OSMI-4 was given concurrently. These findings indicate that the early rise in O-GlcNAcylation is consistent with an acute stress response to LIRI. Pharmacologically maintaining higher O-GlcNAcylation was associated with less severe injury and weaker Caspase-1/GSDMD-related signaling, supporting further investigation of this modification as a therapeutic target in acute LIRI.
Belumosudil (SLX-2119) inhibits rho-associated, coiled-coil containing protein kinase 2 (ROCK2), which mainly functions by regulating inflammatory and adipogenic pathways; however, the effects of belumosudil and its mechanism of action toward pulmonary fibrosis (PF) remain unclear. We conducted in vivo investigations and examined belumosudil effects on PF using an intratracheal bleomycin (BLM) infusion rat model. We then examined mechanisms whereby belumosudil inhibited in vitro-induced PF by determining its effects on transforming growth factor (TGF)-(31-induced mouse lung fibroblasts (proliferation) and lipopolysaccharide-(LPS) or interleukin (IL)-4-induced mouse mononuclear macrophage (RAW264.7) polarization. Continuous belumosudil (20 mg/kg) gavage for 2 weeks elicited protective effects in BLM-induced PF rats, as shown by changes in Hounsfield units, which indicated overall pulmonary function, and lung coefficient and lung microscopic pathology scores, which indicated gross pulmonary pathology. ROCK2, p-Smad3, connective tissue growth factor (CTGF), arginase-1 (Arg-1), and inducible nitric oxide synthase (iNOS) protein levels were also altered. In vitro, belumosudil (100 nM) reduced LPS or IL-4-induced macrophage polarization, lowered Arg-1 and iNOS levels, reduced TGF-(31-induced fibroblast proliferation, and generated lower ROCK2, p-Smad3, and CTGF levels. Belumosudil appeared to alleviate experimental PF by reducing fibroblast proliferation and macrophage polarization by inhibiting ROCK2/Smad3/CTGF signaling.
