Anthelmintic nitazoxanide protects against experimental pulmonary fibrosis.

BACKGROUND AND PURPOSE: Nitazoxanide is a therapeutic anthelmintic drug. Our previous studies found that nitazoxanide and its metabolite tizoxanide activated adenosine 5'-monophosphate-activated protein kinase (AMPK) and inhibited signal transducer and activator of transcription 3 (STAT3) signals. As AMPK activation and/or STAT3 inhibition are targets for treating pulmonary fibrosis, we hypothesized that nitazoxanide would be effective in experimental pulmonary fibrosis. EXPERIMENTAL APPROACH: The mitochondrial oxygen consumption rate of cells was measured by using the high-resolution respirometry system Oxygraph-2K. The mitochondrial membrane potential of cells was evaluated by tetramethyl rhodamine methyl ester (TMRM) staining. The target protein levels were measured by using western blotting. The mice pulmonary fibrosis model was established through intratracheal instillation of bleomycin. The examination of the lung tissues changes were carried out using haematoxylin and eosin (H&E), and Masson staining. KEY RESULTS: Nitazoxanide and tizoxanide activated AMPK and inhibited STAT3 signalling in human lung fibroblast cells (MRC-5 cells). Nitazoxanide and tizoxanide inhibited transforming growth factor-ß1 (TGF-ß1)-induced proliferation and migration of MRC-5 cells, collagen-I and α-smooth muscle cell actin (α-SMA) expression, and collagen-I secretion from MRC-5 cells. Nitazoxanide and tizoxanide inhibited epithelial-mesenchymal transition (EMT) and inhibited TGF-ß1-induced Smad2/3 activation in mouse lung epithelial cells (MLE-12 cells). Oral administration of nitazoxanide reduced the bleomycin-induced mice pulmonary fibrosis and, in the established bleomycin-induced mice, pulmonary fibrosis. Delayed nitazoxanide treatment attenuated the fibrosis progression. CONCLUSIONS AND IMPLICATIONS: Nitazoxanide improves the bleomycin-induced pulmonary fibrosis in mice, suggesting a potential application of nitazoxanide for pulmonary fibrosis treatment in the clinic.

Piezo1 channel activation stimulates ATP production through enhancing mitochondrial respiration and glycolysis in vascular endothelial cells.

BACKGROUND AND PURPOSE: Piezo1 channels are mechanosensitive cationic channels that are activated by mechanical stretch or shear stress. Endothelial Piezo1 activation by shear stress caused by blood flow induces ATP release from endothelial cells; however, the link between shear stress and endothelial ATP production is unclear. EXPERIMENTAL APPROACH: The mitochondrial respiratory function of cells was measured by using high-resolution respirometry system Oxygraph-2k. The intracellular Ca2+ concentration was evaluated by using Fluo-4/AM and mitochondrial Ca2+ concentration by Rhod-2/AM. KEY RESULTS: The specific Piezo1 channel activator Yoda1 or its analogue Dooku1 increased [Ca2+ ]i in human umbilical vein endothelial cells (HUVECs), and both Yoda1 and Dooku1 increased mitochondrial oxygen consumption rates (OCRs) and mitochondrial ATP production in HUVECs and primary cultured rat aortic endothelial cells (RAECs). Knockdown of Piezo1 inhibited Yoda1- and Dooku1-induced increases of mitochondrial OCRs and mitochondrial ATP production in HUVECs. The shear stress mimetics, Yoda1 and Dooku1, and the Piezo1 knock-down technique also demonstrated that Piezo1 activation increased glycolysis in HUVECs. Chelating extracellular Ca2+ with EGTA or chelating cytosolic Ca2+ with BAPTA-AM did not affect Yoda1- and Dooku1-induced increases of mitochondrial OCRs and ATP production, but chelating cytosolic Ca2+ inhibited Yoda1- and Dooku1-induced increase of glycolysis. Confocal microscopy showed that Piezo1 channels are present in mitochondria of endothelial cells, and Yoda1 and Dooku1 increased mitochondrial Ca2+ in endothelial cells. CONCLUSION AND IMPLICATIONS: Piezo1 channel activation stimulates ATP production through enhancing mitochondrial respiration and glycolysis in vascular endothelial cells, suggesting a novel role of Piezo1 channel in endothelial ATP production.

Enhanced degradation of poly(ethylene terephthalate) by the addition of lactic acid / glycolic acid: composting degradation, seawater degradation behavior and comparison of degradation mechanism.

The degradability improvement of poly(ethylene terephthalate) (PET), one of the most widely used but non-degradable disposable packaging material, is of great significance. However, the balance between degradability and mechanical properties remains a huge challenge. Herein, simple hydroxy acids, lactic acid (LA) and glycolic acid (GA) as easy hydrolysis sites were introduced into non-degradable PET via melt polycondensation. A series of high molecular weight poly(ethylene terephthalate-co-L­lactide) (PETL) and poly(ethylene terephthalate-co-glycolate) (PETG) copolyesters were synthesized with an excellent tensile strength greater than 50 MPa, much higher than that of most commercially available degradable polymers. The introduction of hydroxy acid endows PET with significantly improved composting and seawater degradation performance. Furtherly, the degradation rate of PETG with hydrophilic GA unit was faster than that of PETL, and the mineralization rate of PETG80 reaches 22.0%. The density of functional theory (DFT) calculation revealed that adding hydroxy acid to the PET molecular chain reduced the energy barrier of the hydrolysis reaction. The molecular polarity index (MPI) analysis furtherly confirmed that the higher affinity between the GA unit and water may be the primary reason for the faster degradation of PETG.