An Osmium(VI) Nitride Triggers Mitochondria-induced Oncosis and Apoptosis

We report a new osmium(VI) nitrido complex bearing a nonplanar tetradentate ligand with potent anticancer activity. It causes mitochondrial damage, which induces liver cancer cell death via oncosis and apoptosis....

P75NTR exacerbates SCI-induced mitochondrial damage and neuronal apoptosis depending on NTRK3

Objective: The aim of the study was to investigate the mechanism by which p75 neurotrophin receptor (p75NTR) affects mitochondrial damage and neuronal apoptosis in spinal cord injury (SCI). Methods: After the establishment of SCI rat models, short hairpin (sh) RNA of p75NTR and control sh-RNA were injected into SCI rats, respectively. On days 1, 7 and 21 after SCI, the severity of SCI and cell apoptosis in SCI rats were determined as well as the recovery of hind limb performance and p75NTR expression. After spinal cord neurons were transfected with p75NTR overexpression plasmid or empty plasmid vector or cotransfected with overexpression plasmids of p75NTR and neurotrophic tyrosine receptor kinase3 (NTRK3), the expression levels of p75NTR and NTRK3 were quantified. Moreover, we detected the apoptosis and proliferation rates of the neurons in addition to the levels of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) in the neurons. The binding between p75NTR and NTRK3 was confirmed via Co-immunoprecipitation (Co-IP). Results: The rat spinal cords in the Model group were notably damaged after SCI accompanied by increased apoptosis and decreased locomotor function. The expression of p75NTR was significantly upregulated after SCI. The aforementioned injuries were remarkably ameliorated in response to injection of sh-p75NTR. p75NTR overexpression induced mitochondrial damage and neuronal apoptosis in spinal cord neurons, while the promotive effects were perturbed by NTRK3 overexpression. Furthermore, p75NTR directly bound to and downregulated NTRK3. Conclusion: Both in vivo and in vitro experiments showed that p75NTR aggravates mitochondrial damage and neuronal apoptosis in SCI through downregulating NTRK3.

Cell-free chromatin particles released from dying cells inflict mitochondrial damage and ROS production in living cells

Several hundred billion to a trillion cells die in the body every day and release cell free chromatin particles (cfChPs) which enter into the circulation, or are released locally into extracellular compartments of the body. We have reported that cfChPs from the dying cells can readily enter into living cells and damage their DNA. To test the hypothesis that internalised cfChPs might also inflict mitochondrial damage, we treated NIH3T3 mouse fibroblast cells with cfChPs isolated from sera of healthy individuals (10ng), or co-cultured the cells with hypoxia induced dying NIH3T3 cells. Abundant cfChPs could be detected in the cytoplasm of the treated cells by 4h. The latter was associated with evidence of mitochondrial damage in the form of ultra-structural changes, increased mitochondrial mass, alterations in mitochondrial shape, upregulation of the mitochondrial outer membrane protein TOM20, and changes in mitochondrial membrane potential. We also detected increased fluorescence signals of gamma-H2AX and p-ATM signifying double-strand breaks in mitochondrial DNA. There was marked increase in production of mitochondrial superoxide (ROS) as detected by MitoSOX Red, and activation of the intracellular antioxidant enzyme superoxide dismutase-1. Mitochondrial damage and ROS production could be inhibited by a cfChPs deactivating agent viz. anti-histone antibody complexed nanoparticles. Given that 1x109-1x1012 cells die in the body every day, we propose that cfChPs are major physiological triggers for mitochondrial damage and ROS production with an important bearing on human health and disease. Deactivation of cfChPs may provide a novel therapeutic approach to retard ageing and associated degenerative conditions that have been linked to oxidative stress.

Flurochloridone Induced Abnormal Spermatogenesis by Damaging Testicular Sertoli Cells in Mice

BackgroundFlurochloridone (FLC), a selective herbicide used on a global scale, has been reported to have male reproductive toxicity which evidence is limited and the mechanism is still unclear. The present study was conducted to systematically explore the male reproductive toxicity of FLC, including sperm quality, spermatogenesis process, toxicity targets and possible mechanisms. MethodsMale C57BL/6 mice aged 6-7 weeks received gavage administration of FLC (365/730 mg/kg body weight) for 28 consecutive days. Then the tissue and sperm of mice were collected for analysis. We measured the coefficient of male reproductive organs, and analyzed sperm concentration, motility, malformation rate and mitochondrial membrane potential. Spermatocyte immunofluorescence staining was performed to analyze meiosis processes. At the same time, we performed pathological staining on the testis and epididymis tissue, and performed TUNEL staining, immunohistochemical analysis and ultrastructural observation on the testicular tissue.ResultsThe results showed that FLC caused mice testicular weight reduction, dysfunction and architectural damage, but no significant adverse effect was found in epididymis. The exposure interfered with the proliferation of spermatogonia and the process of meiosis, affecting sperm concentration, motility, kinematic parameters, morphology and mitochondrial membrane potential, leading to sperm quality decline. Furthermore, mitochondrial damage and apoptosis of testicular Sertoli cells were observed in mice treated with FLC. ConclusionWe found that FLC has significant adverse effects on spermatogonia proliferation and meiosis. Meanwhile, apoptosis and mitochondrial damage may be the potential mechanism of Sertoli cell damage. Our study demonstrated that FLC could induce testicular Sertoli cell damage, leading to abnormal spermatogenesis which resulted in sperm quality decline and provided a methodological reference for related studies.