Life sciences最新文献

Aim: This study aimed to repurpose FDA-approved drugs for the treatment of mitochondrial complex I diseases.

Materials and methods: The NUO-51 protein of the filamentous fungus Podospora anserina is the homolog of the human key catalytic subunit of complex I, NDUFV1. By introducing a pathogenic mutation into P. anserina NUO-51 we created a novel model of complex I deficiency targeting the NDUFV1 subunit. The thermosensitive phenotype of the fungal mutant enabled us to screen a library of nearly one thousand FDA-approved molecules. We have implemented various techniques such as growth analysis, oxygen consumption measurements, complex I activity assays and western blotting on Podospora, Caenorhabditis elegans and human on equivalent NDUFV1 mutant models, treated or untreated with the most effective drugs found during the screen.

Key findings: We isolated a series of compounds able to rescue the growth defect of the Podospora nuo-51 mutant, including ligands of serotonin receptors or transporters. Among the selected drugs, alverine citrate (ALV) and dapoxetine hydrochloride (DAP) emerged as the most active drugs. Both drugs enhanced respiration and complex I activity, not only in the Podospora mutant, but also in Caenorhabditis elegans worms deficient for the NDUFV1 ortholog and in fibroblasts from patient carrying NDUFV1 mutations.

Significance: Together, our work demonstrates the usefulness of Podospora anserina as fungal model for identifying promising therapeutic candidates for complex I diseases, paving the way for future clinical trials.

Background: SGLT2 inhibitor dapagliflozin (Dapa) has gained increasing attention in the treatment of myocardial ischemia-reperfusion injury (IRI). However, the mechanism of action of the cardiovascular benefits of Dapa is unclear. The present study aimed to investigate the effects of Dapa on myocardial IRI and the underlying molecular mechanisms.

Methods: The effects of Dapa on myocardial IRI were investigated using the in vitro perfusion Langendorf model and the in vitro hypoxia/reoxygenation (H/R) cell model. Histological changes, myocardial enzymes, oxidative stress and mitochondrial structure/function were assessed. Mechanistic studies involved various molecular biology methods such as ELISA, immunoprecipitation, western blot, immunofluorescence and Bioinformatics.

Results: Our findings demonstrate that Dapa upregulates EGFR phosphorylation, suppresses NHE1 expression in myocardial tissues, modulates NCOA4-mediated ferritinophagy to enhance mitochondrial function, reduces ROS expression, and mitigates myocardial IRI. In the Langendorf model, Dapa effectively attenuates cardiac dysfunction, myocardial injury, mitochondrial damage, and oxidative imbalance induced by ischemia-reperfusion. In vitro experiments revealed that blocking EGFR or autophagy with inhibitors (AG and Baf, respectively) or inducing ferroptosis with Era promotes ROS release, exacerbates mitochondrial injury, and diminishes the protective effects of Dapa. Notably, Era did not affect NCOA4-mediated ferritinophagy. Conversely, the EGFR agonist NSC counteracted these effects, underscoring that Dapa confers cardioprotection by modulating mitochondrial function through EGFR-mediated regulation of NCOA4-mediated ferritinophagy.

Conclusion: In summary, Dapa activates EGFR phosphorylation, regulates NCOA4-mediated ferritinophagy, modulates mitochondrial function, and effectively mitigates myocardial IRI. These findings provide a robust theoretical foundation for the clinical application of Dapa in treating cardiovascular conditions.

Aims: To define the clinical relevance and mechanistic role of Ezrin (EZR) in breast cancer progression, metastasis, and paclitaxel resistance.

Materials and methods: We integrated public expression/survival datasets with tissue immunohistochemistry, and used stable EZR silencing in MDA-MB-231 cells combined with phenotypic assays, phospho-kinase profiling with immunoblot validation and STAT3 activation rescue, plus orthotopic xenograft and experimental lung colonization models; paclitaxel-resistant sublines were generated to test chemoresistance.

Key findings: EZR was overexpressed in breast cancer and correlated with poorer overall survival (HR = 1.21, p = 0.048), with high EZR detected in 55.6% (20/36) of tumours in our cohort. EZR depletion reduced proliferation and migration/invasion while inducing apoptosis, and suppressed tumour growth and lung metastasis in vivo. Mechanistically, EZR sustained STAT3 Tyr705 phosphorylation and downstream pro-survival outputs, and physically interacted with TPM3, implicating cytoskeletal coupling; STAT3 activation partially rescued EZR-loss phenotypes. EZR was elevated in paclitaxel-resistant cells, and EZR knockdown increased paclitaxel sensitivity.

Significance: EZR links cytoskeletal remodeling to STAT3 signalling to drive metastatic competence and paclitaxel resistance, nominating EZR as a potential therapeutic vulnerability in treatment-refractory breast cancer.

Receptors for orexigenic hormones are broadly expressed in different tissues. Growth hormone secretagogue receptor (GHSR) is the receptor for the gastric peptide hormone ghrelin, although it further displays an intrinsic ligand-independent activity. The liver-expressed antimicrobial peptide 2 (LEAP2) has been recently identified as GHSR endogenous antagonist and inverse agonist. To understand LEAP2 effects on cardiac performance, we assessed (in-vivo) Wistar (WT) and spontaneously hypertensive rats (SHR), isolated hearts (ex-vivo) and cardiomyocytes (in-vitro). Intravenous LEAP2 injection reduced arterial pressure, with a greater effect in SHR. LEAP2 also reduced cardiac inotropism in both WT and SHR, whereas a negative chronotropy was observed only in SHR. LEAP2 perfusion reduced intraventricular pressure in isolated SHR hearts and attenuated the responses to isoproterenol on coronary flow, whereas responses to acetylcholine were almost unaffected by LEAP2. Fluorescent LEAP2 or ghrelin labeled cardiomyocytes. LEAP2 or the synthetic inverse agonist PF04628935 produced an equipotent reduction in maximum contraction speed, reduced cardiomyocyte shortening area, and attenuated the responses to isoproterenol, but not to acetylcholine. Plasma levels of ghrelin and LEAP2 were not different between strains, but higher GHSR levels were found in SHR hearts. In conclusion, LEAP2 exerted marked cardiovascular effects, reducing arterial pressure and left ventricular systolic performance in both WT and SHR, with a greater impact in hypertensive animals. However, GHSR involvement in SHR cardiac abnormalities is unrelated to the circulating levels of its endogenous ligands and instead seems to depend on altered cardiac GHSR expression and function. The cardiac LEAP2 interaction with β-adrenergic receptors reveals an important cardioprotective potential.