Hydroethanolic extract of Cirsium setidens ameliorates doxorubicin-induced cardiotoxicity by AMPK-PGC-1α-SOD-mediated mitochondrial protection.

BACKGROUND: Doxorubicin (DOX) is an effective anticancer agent. However, the clinical outcomes of DOX-based therapies are severely hampered by their significant cardiotoxicity. PURPOSE: We investigated the beneficial effects of an ethanol extract of Cirsium setidens (CSE) on DOX-induced cardiomyotoxicity (DICT). METHODS: UPLC-TQ/MS analysis was used to identify CSE metabolite profiles. H9c2 rat cardiomyocytes and MDA-MB-231 human breast cancer cells were used to evaluate the effects of CSE on DICT-induced cell death. To elucidate the mechanism underlying it, AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor gamma co-activator l-alpha (PGC1-α), nuclear respiratory factor 1 (NRF1), NRF2, superoxide dismutase (SOD1), and SOD2 expression was detected using western blot analysis. The oxygen consumption rate (OCR), cellular ROS, and mitochondrial membrane potential were measured. Finally, we confirmed the cardioprotective effect of CSE against DICT in both C57BL/6 mice and human induced pluripotent stem cell-derived cardiomyocytes (hiPSCCMs) by observing various parameters, such as electrophysiological changes, cardiac fibrosis, and cardiac cell death. RESULTS: Chlorogenic acid and nicotiflorin were the major compounds in CSE. Our data demonstrated that CSE blocked DOX-induced cell death of H9c2 cells without hindrance of its apoptotic effects on MDA-MB-231 cells. DOX-induced defects of OCR and mitochondrial membrane potential were recovered in a CSE through upregulation of the AMPK-PGC1-α-NRF1 signaling pathway. CSE accelerated NRF1 translocation to the nucleus, increased SOD activity, and consequently blocked apoptosis in H9c2 cells. In mice treated with 400 mg/kg CSE for 4 weeks, electrocardiogram data, creatine kinase and lactate dehydrogenase levels in the serum, and cardiac fibrosis, were improved. Moreover, various electrophysiological features indicative of cardiac function were significantly enhanced following the CSE treatment of hiPSCCMs. CONCLUSION: Our findings demonstrate CSE that ameliorates DICT by protecting mitochondrial dysfunction via the AMP- PGC1α-NRF1 axis, underscoring the therapeutic potential of CSE and its underlying molecular pathways, setting the stage for future investigations into its clinical applications.

Large electroabsorption susceptibility mediated by internal photoconductive gain in Ge nanowires.

Large spectral modulation in the photon-to-electron conversion near the absorption band-edge of a semiconductor by an applied electrical field can be a basis for efficient electro-optical modulators. This electro-absorption effect in Group IV semiconductors is, however, inherently weak, and this poses the technological challenges for their electro-photonic integration. Here we report unprecedentedly large electro-absorption susceptibility at the direct band-edge of intrinsic Ge nanowire (NW) photodetectors, which is strongly diameter-dependent. We provide evidence that the large spectral shift at the 1.55 µm wavelength, enhanced up to 20 times larger than Ge bulk crystals, is attributed to the internal Franz-Keldysh effect across the NW surface field of ~10(5) V/cm, mediated by the strong photoconductive gain. This classical size-effect operating at the nanometer scale is universal, regardless of the choice of materials, and thus suggests general implications for the monolithic integration of Group IV photonic circuits.