LIN28A enhances regenerative capacity of human somatic tissue stem cells via metabolic and mitochondrial reprogramming.

Developing methods to improve the regenerative capacity of somatic stem cells (SSCs) is a major challenge in regenerative medicine. Here, we propose the forced expression of LIN28A as a method to modulate cellular metabolism, which in turn enhances self-renewal, differentiation capacities, and engraftment after transplantation of various human SSCs. Mechanistically, in undifferentiated/proliferating SSCs, LIN28A induced metabolic reprogramming from oxidative phosphorylation (OxPhos) to glycolysis by activating PDK1-mediated glycolysis-TCA/OxPhos uncoupling.

Thyroid Hormone Induces Ca-Mediated Mitochondrial Activation in Brown Adipocytes.

Thyroid hormones, including 3,5,3'-triiodothyronine (T), cause a wide spectrum of genomic effects on cellular metabolism and bioenergetic regulation in various tissues. The non-genomic actions of T have been reported but are not yet completely understood. Acute T treatment significantly enhanced basal, maximal, ATP-linked, and proton-leak oxygen consumption rates (OCRs) of primary differentiated mouse brown adipocytes accompanied with increased protein abundances of uncoupling protein 1 (UCP1) and mitochondrial Ca uniporter (MCU).

Ca-activated mitochondrial biogenesis and functions improve stem cell fate in Rg3-treated human mesenchymal stem cells.

Although mitochondrial functions are essential for cell survival, their critical roles in stem cell fate, including proliferation, differentiation, and senescence, remain elusive. Ginsenoside Rg3 exhibits various biological activities and reportedly increases mitochondrial biogenesis and respiration. Herein, we observed that Rg3 increased proliferation and suppressed senescence of human bone marrow-derived mesenchymal stem cells.

Oxidative stress by Ca overload is critical for phosphate-induced vascular calcification.

Hyperphosphatemia is the primary risk factor for vascular calcification, which is closely associated with cardiovascular morbidity and mortality. Recent evidence showed that oxidative stress by high inorganic phosphate (Pi) mediates calcific changes in vascular smooth muscle cells (VSMCs). However, intracellular signaling responsible for Pi-induced oxidative stress remains unclear.

Activation of ERK1/2-mTORC1-NOX4 mediates TGF-β1-induced epithelial-mesenchymal transition and fibrosis in retinal pigment epithelial cells.

Transforming growth factor-β (TGF-β) plays a crucial role in the development of epithelial to mesenchymal transition (EMT) and fibrosis, particularly in an ocular disorder such as proliferative vitreoretinopathy (PVR). However, the key molecular mechanism underlying its pathogenesis remains unknown. In the present study, using cultured ARPE-19 cells, we determined that TGF-β initiates a signaling pathway through extracellular signal-regulated kinase (ERK)-mammalian target of rapamycin complex 1 (mTORC1) that stimulates trans-differentiation and fibrosis of retinal pigment epithelium.

Mitochondrial Ca Uptake Relieves Palmitate-Induced Cytosolic Ca Overload in MIN6 Cells.

Saturated fatty acids contribute to β-cell dysfunction in the onset of type 2 diabetes mellitus. Cellular responses to lipotoxicity include oxidative stress, endoplasmic reticulum (ER) stress, and blockage of autophagy. Palmitate induces ER Ca depletion followed by notable store-operated Ca entry.