900 MHz Radiofrequency Field Induces Mitochondrial Unfolded Protein Response in Mouse Bone Marrow Stem Cells

Mitochondria-specific antioxidant MitoTEMPO alleviates senescence of bone marrow mesenchymal stem cells in ovariectomized rats

Senescence in bone marrow mesenchymal stem cells (BMSCs), triggered by excessive oxidative stress, plays a crucial role in the onset of postmenopausal osteoporosis. Recent studies underscore the importance of mitochondrial rehabilitation and quality control as key determinants in the modulation of oxidative stress and cellular senescence. MitoTEMPO, a mitochondria-targeted antioxidant, has been shown to mitigate the heightened levels of reactive oxygen species (ROS). In our research, we observed that BMSCs from ovariectomized (OVX) rats displayed premature senescence, which was attributed to combined mitochondrial and lysosomal dysfunction, a condition that worsens with extended estrogen deprivation. Treatment with MitoTEMPO effectively reversed these effects, reinstating lysosomal functionality and suppressing the mitochondrial unfolded protein response (UPRmt). Subsequent in vivo experiments corroborated these observations, revealing that MitoTEMPO administration in OVX rats curtailed trabecular bone loss and reduced the expression of p53, HSP60, and CLPP in the trabecular bone region of the proximal tibia. Overall, our findings suggest that MitoTEMPO holds promise as a therapeutic agent to counteract senescence in OVX-BMSCs, offering a potential strategy for treating postmenopausal osteoporosis.

Autophagy and the unfolded protein response shape the non-alcoholic fatty liver landscape: decoding the labyrinth

The incidence of nonalcoholic fatty liver disease (NAFLD) is on the rise, mirroring a global surge in diabetes and metabolic syndrome, as its major leading causes. NAFLD represents a spectrum of liver disorders, ranging from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH), which can potentially progress to cirrhosis and hepatocellular carcinoma (HCC). Mechanistically, we know the unfolded protein response (UPR) as a protective cellular mechanism, being triggered under circumstances of endoplasmic reticulum (ER) stress. The hepatic UPR is turned on in a broad spectrum of liver diseases, including NAFLD. Recent data also defines molecular mechanisms that may underlie the existing correlation between UPR activation and NAFLD. More interestingly, subsequent studies have demonstrated an additional mechanism, i.e. autophagy, to be involved in hepatic steatosis, and thus NAFLD pathogenesis, principally by regulating the insulin sensitivity, hepatocellular injury, innate immunity, fibrosis, and carcinogenesis. All these findings suggest possible mechanistic roles for autophagy in the progression of NAFLD and its complications. Both UPR and autophagy are dynamic and interconnected fluxes that act as protective responses to minimize the harmful effects of hepatic lipid accumulation, as well as the ER stress during NAFLD. The functions of UPR and autophagy in the liver, together with findings of decreased hepatic autophagy in correlation with conditions that predispose to NAFLD, such as obesity and aging, suggest that autophagy and UPR, alone or combined, may be novel therapeutic targets against the disease. In this review, we discuss the current evidence on the interplay between autophagy and the UPR in connection to the NAFLD pathogenesis.

Inhibition of mitochondrial calcium uptake by Ru360 enhances the effect of 1800 MHz radio-frequency electromagnetic fields on DNA damage

Today, the existence of radio-frequency electromagnetic fields (RF-EMF) emitted from cell phones, wireless routers, base stations, and other sources are everywhere around our living environment, and the dose is increasing. RF-EMF have been reported to be cytotoxic and supposed to be a risk factor for various human diseases, thus, more attention is necessary. In recent years, interfere with mitochondrial calcium uptake by using mitochondrial calcium uniporter (MCU) inhibitor were suggested to be potential clinical treatment in mitochondrial calcium overload diseases, like neurodegeneration, ischemia/reperfusion injury, and cancer, but whether this approach increases the health risk of RF-EMF exposure are unknown. To address our concern, we did a preliminary study to determine whether inhibition of MCU will increase the genotoxicity of RF-EMF exposure in cells, and found that short-time (15 min) exposure to 1800 MHz RF-EMF induced significant DNA damage and cell apoptosis in mouse embryonic fibroblasts (MEFs) treated with Ruthenium 360 (Ru360), a specific inhibitor of MCU, but no significant effects on cell cycle, cell proliferation, or cell viability were observed. In conclusion, our results indicated that inhibiting MCU increases the genotoxicity of RF-EMF exposure, and more attention needs to be paid to the possible health impact of RF-EMF exposure under these treatments.

Paternal Radiofrequency Electromagnetic Radiation Exposure Causes Sex-Specific Differences in Body Weight Trajectory and Glucose Metabolism in Offspring Mice

Nowadays, concerns about the harmful effects of radiofrequency electromagnetic radiation (RF-EMR) on male fertility and offspring health are growing. In the present study, we investigated the effects of long-term exposure (at least 10 weeks) to the RF-EMR [2.0 GHz; power density, 2.5 W/m2; whole-body specific absorption rate (SAR), 0.125-0.5 W/kg] on male mice fertility and F1 growth and glucose metabolism. No significant injuries were observed in testis organization, sperm quality, and pregnancy rate. However, mice exposed to RF-EMR exhibited a significantly elevated apoptosis rate in testis germ cells. Interestingly, paternal RF-EMR exposure resulted in sex-specific weight trajectory differences and glucose metabolism changes in male F1 mice but not in female F1 mice. The changed glucose metabolism in F1 male may result from the altered gene expression of liver Gck. These data collectively suggested that 2.0 GHz RF-EMR whole-body exposure of male mice does not cause obvious impairment in testis, sperm quality, and pregnancy rate. Paternal RF-EMR exposure causes male-specific alterations in body weight trajectories and glucose metabolism of F1.

The roles of intensity, exposure duration, and modulation on the biological effects of radiofrequency radiation and exposure guidelines

In this paper, we review the literature on three important exposure metrics that are inadequately represented in most major radiofrequency radiation (RFR) exposure guidelines today: intensity, exposure duration, and signal modulation. Exposure intensity produces unpredictable effects as demonstrated by nonlinear effects. This is most likely caused by the biological system's ability to adjust and compensate but could lead to eventual biomic breakdown after prolonged exposure. A review of 112 low-intensity studies reveals that biological effects of RFR could occur at a median specific absorption rate of 0.0165 W/kg. Intensity and exposure duration interact since the dose of energy absorbed is the product of intensity and time. The result is that RFR behaves like a biological "stressor" capable of affecting numerous living systems. In addition to intensity and duration, man-made RFR is generally modulated to allow information to be encrypted. The effects of modulation on biological functions are not well understood. Four types of modulation outcomes are discussed. In addition, it is invalid to make direct comparisons between thermal energy and radiofrequency electromagnetic energy. Research data indicate that electromagnetic energy is more biologically potent in causing effects than thermal changes. The two likely functionthrough different mechanisms. As such, any current RFR exposure guidelines based on acute continuous-wave exposure are inadequate for health protection.