Mitochondrial dysfunction promotes the necroptosis of Purkinje cells in the cerebellum of acrylamide-exposed rats

Dietary acrylamide disrupts the functioning of the biological clock

Acrylamide (ACR) is a known carcinogen and neurotoxin. It is chronically consumed in carbohydrate-rich snacks processed at high temperatures. This calls for systematic research into the effects of ACR intake, best performed in an experimental model capable of detecting symptoms of its neurotoxicity at both high and low doses. Here, we study the influence of 10 µg/g (corresponding to the concentrations found in food products) and, for comparison, 60, 80 and 110 µg/g dietary ACR, on the fruit fly Drosophila melanogaster. We show that chronic administration of ACR affects lifespan, activity level and, most importantly, the daily and circadian pattern of locomotor activity of Drosophila. ACR-treated flies show well-defined and concentration-dependent symptoms of ACR neurotoxicity; a reduced anticipation of upcoming changes in light conditions and increased arrhythmicity in constant darkness. The results suggest that the rhythm-generating neural circuits of their circadian oscillator (biological clock) are sensitive to ACR even at low concentrations if the exposure time is sufficiently long. This makes the behavioural readout of the clock, the rhythm of locomotor activity, a useful tool for studying the adverse effects of ACR and probably other compounds.

Reactive Oxygen Species-Mediated Mitophagy and Cell Apoptosis are Involved in the Toxicity of Aluminum Chloride Exposure in GC-2spd

Aluminum chloride is an inorganic polymeric coagulant commonly found in daily life and various materials. Although male reproductive toxicity has been associated with AlCl3 exposure, the underlying mechanism remains unclear. This study aimed to examine the impact of AlCl3 exposure on mitophagy and mitochondrial apoptosis in testicular tissue and mouse spermatocytes. Reactive oxygen species (ROS) and ATP levels were measured in GC-2spd after AlCl3 exposure using a multifunctional enzyme labeler. The changes in mitochondrial membrane potential (MMP) and TUNEL were observed through confocal laser microscopy, and the expression of proteins associated with mitophagy and apoptosis was analyzed using Western blot. Our results demonstrated that AlCl3 exposure disrupted mitophagy and increased apoptosis-related protein expression in testicular tissues. In the in vitro experiments, AlCl3 exposure induced ROS production, suppressed cell viability and ATP production, and caused a decrease in MMP, leading to mitophagy and cell apoptosis in GC-2spd cells. Intervention with N-acetylcysteine (NAC) reduced ROS production and partially restored mitochondrial function, thereby reversing the resulting mitophagy and cell apoptosis. Our findings provide evidence that ROS-mediated mitophagy and cell apoptosis play a crucial role in the toxicity of AlCl3 exposure in GC-2spd. These results contribute to the understanding of male reproductive toxicity caused by AlCl3 exposure and offer a foundation for future research in this area.

Baicalin ameliorates deficient decidualization in URSA by regulating mitochondrial fission induced necroptosis

Unexplained recurrent spontaneous abortion (URSA) is a common complication of pregnancy that affects the health of pregnant women. Deficient endometrial decidualization has been associated with URSA. However, the underlying mechanism is poorly understood. This study aims to explore the mechanisms of mitochondrial fission induced necroptosis in deficient decidualization in URSA, and explore the regulation of baicalin on this mechanism. Initially, decidual tissues were collected from patients with URSA and health controls. Subsequently, in vitro induced decidualization model of Telomerase-Immortalized Human Endometrial Stromal Cells (T-hESCs) was constructed. Additionally, murine models of URSA (CBA/J × DBA/2) and normal pregnancy (CBA/J × BALB/c) were established, respectively. The level of decidualization, necroptosis, and mitochondrial fission of decidual tissues from clinical samples were detected. The function of mitochondrial fission on necroptosis during decidualization in T-hESCs was assessed by enhancing or inhibiting mitochondrial fission or necroptosis. Finally, CBA/J × DBA/2 pregnant mice were administrated with different doses of baicalin or saline, and the expression of mitochondrial fission, necroptosis, and decidualization markers were verified. The results of the study demonstrated a significant decrease in decidualization markers in the decidual tissues of URSA patients (P < 0.05), along with an increase in the incidence of cell necroptosis (P < 0.05) and hyperactive mitochondrial fission (P < 0.05). In vitro experiments, LPS was induced to trigger necroptosis of T-hESCs during induced decidualization, and decidualization markers IGFBP1 and PRL were subsequently decreased (P < 0.05). Besides, the mitochondrial fission agonist Tyrphostin A9 was found to promote the level of necroptosis (P < 0.05) and induced deficient decidualization (P < 0.05), which could be rescued by mitochondrial fission inhibitor Mdivi-1 and necroptosis inhibitor Nec-1 (P < 0.05). In addition, baicalin was shown to reduce hyperactive mitochondrial fission (P < 0.05), necroptosis (P < 0.05) and ameliorate deficient decidualization in vitro and in URSA murine models (P < 0.05). Collectively, baicalin shows potential in ameliorating deficient decidualization in URSA by inhibiting mitochondrial fission-triggered necroptosis.

Neutrophil extracellular traps aggravate intestinal epithelial necroptosis in ischaemia-reperfusion by regulating TLR4/RIPK3/FUNDC1-required mitophagy

Neutrophil extracellular trap (NET) has been confirmed to be related to gut barrier injury during intestinal ischaemia-reperfusion (II/R). However, the specific molecular regulatory mechanism of NETs in II/R-induced intestinal barrier damage has yet to be fully elucidated. Here, we reported increased NETs infiltration accompanied by elevated inflammatory cytokines, cellular necroptosis and tight junction disruption in the intestine of human II/R patients. Meanwhile, NETs aggravated Caco-2 intestinal epithelial cell necroptosis, impairing the monolayer barrier in vitro. Moreover, Pad4-deficient mice were used further to validate the role of NETs in II/R-induced intestinal injury. In contrast, NET inhibition via Pad4 deficiency alleviated intestinal inflammation, attenuated cellular necroptosis, improved intestinal permeability, and enhanced tight junction protein expression. Notably, NETs prevented FUN14 domain-containing 1 (FUNDC1)-required mitophagy activation in intestinal epithelial cells, and stimulating mitophagy attenuated NET-associated mitochondrial dysfunction, cellular necroptosis, and intestinal damage. Mechanistically, silencing Toll-like receptor 4 (TLR4) or receptor-interacting protein kinase 3 (RIPK3) via shRNA relieved mitophagy limitation, restored mitochondrial function and reduced NET-induced necroptosis in Caco-2 cells, whereas this protective effect was reversed by TLR4 or RIPK3 overexpression. The regulation of TLR4/RIPK3/FUNDC1-required mitophagy by NETs can potentially induce intestinal epithelium necroptosis.

Deregulated mitochondrial quality control, the heel of Achilles in elucidating the role of autophagy in SARM1-mediated axon degeneration

Autophagic dysfunction in neurodegenerative diseases is being extensively studied, yet the exact mechanism of macroautophagy/autophagy in axon degeneration is still elusive. A recent study by Kim et al. links autophagic stress to the sterile α and toll/interleukin 1 receptor motif containing protein 1 (SARM1)-dependent core axonal degeneration program, providing a new insight into the role of autophagy in axon degeneration. In the classical Wallerian axon degeneration model of axotomy, disruption of axonal transport destroys the coordinated activity of pro-survival and pro-degenerative factors in the axoplasm and activates the NADase activity of SARM1, thus triggering the axonal self-destruction program. However, the mechanism for SARM1 activation in the chronic neurodegenerative disorders is more complex. Mitochondrial defects and oxidative stress contribute to the activation of SARM1, while mitophagy can inhibit mitochondrial dysfunction and promote the clearance of SARM1 on mitochondria, thus protecting against neuronal degeneration. Therefore, in-depth elucidation of the underlying mechanisms of mitophagy during axonal degeneration can help develop promising strategies for the prevention and treatment of various neurodegenerative disorders.

High-fat diet exacerbated motor dysfunction via necroptosis and neuroinflammation in acrylamide-induced neurotoxicity in mice

Health risks associated with acrylamide (ACR) or high-fat diet (HFD) exposure alone have been widely concerned in recent years. In a realistic situation, ACR and HFD are generally co-existence, and both are risk factors for the development of neurological diseases. The purpose of the present study was to investigate the combined effects of ACR and HFD on the motor nerve function. As a result, neurobehavioral tests and Nissl staining disclosed that long-term HFD exacerbated motor dysfunction and the damage of spinal cord motor neurons in ACR-exposed mice. Co-exposure of ACR and HFD resulted in morphological changes in neuronal mitochondria of the spinal cord, a significantly reduced mitochondrial subunits NDUFS1, UQCRC2, and MTCO1, released the mitochondrial DNA (mtDNA) into the cytoplasm, and promoted the production of reactive oxygen species (ROS). Combined exposure of HFD and ACR activated the calpain/CDK5/Drp1 axis and caused the mitochondrial excessive division, ultimately increasing MLKL-mediated necroptosis in spinal cord motor neurons. Meanwhile, HFD significantly exacerbated ACR-induced activation of NFkB, NLRP3 inflammasome, and cGAS-STING pathway. Taken together, our findings demonstrated that combined exposure of ACR and HFD aggravated the damage of spinal cord motor neurons via neuroinflammation and necroptosis signaling pathway, pointing to additive effects in mice than the individual stress effects.

Comprehensive analysis of mitochondrial dysfunction and necroptosis in intracranial aneurysms from the perspective of predictive, preventative, and personalized medicine

Mitochondrial dysfunction and necroptosis are closely associated, and play vital roles in the medical strategy of multiple cardiovascular diseases. However, their implications in intracranial aneurysms (IAs) remain unclear. In this study, we aimed to explore whether mitochondrial dysfunction and necroptosis could be identified as valuable starting points for predictive, preventive, and personalized medicine for IAs. The transcriptional profiles of 75 IAs and 37 control samples were collected from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs), weighted gene co-expression network analysis, and least absolute shrinkage and selection operator (LASSO) regression were used to screen key genes. The ssGSEA algorithm was performed to establish phenotype scores. The correlation between mitochondrial dysfunction and necroptosis was evaluated using functional enrichment crossover, phenotype score correlation, immune infiltration, and interaction network construction. The IA diagnostic values of key genes were identified using machine learning. Finally, we performed the single-cell sequencing (scRNA-seq) analysis to explore mitochondrial dysfunction and necroptosis at the cellular level. In total, 42 IA-mitochondrial DEGs and 15 IA-necroptosis DEGs were identified. Screening revealed seven  key genes invovled in mitochondrial dysfunction (KMO, HADH, BAX, AADAT, SDSL, PYCR1, and MAOA) and five genes involved in necroptosis (IL1B, CAMK2G, STAT1, NLRP3, and BAX). Machine learning confirmed the high diagnostic value of these key genes for IA. The IA samples showed  higher expression of mitochondrial dysfunction and necroptosis. Mitochondrial dysfunction and necroptosis exhibited a close association. Furthermore, scRNA-seq indicated that mitochondrial dysfunction and necroptosis were preferentially up-regulated in monocytes/macrophages and vascular smooth muscle cells (VSMCs) within IA lesions. In conclusion, mitochondria-induced necroptosis was involved in IA formation, and was mainly up-regulated in monocytes/macrophages and VSMCs within IA lesions. Mitochondria-induced necroptosis may be a novel potential target for diagnosis, prevention, and treatment of IA.

Repeated administration of acrylamide for 28 days suppresses adult neurogenesis of the olfactory bulb in young-adult rats

Acrylamide (AA) is a neurotoxicant that inhibits synaptic function in distal axons. We previously found that AA decreased neural cell lineages during late-stage differentiation of adult hippocampal neurogenesis and downregulated genes related to neurotrophic factor, neuronal migration, neurite outgrowth, and synapse formation in the hippocampal dentate gyrus in rats. To investigate whether olfactory bulb (OB)-subventricular zone (SVZ) neurogenesis is similarly affected by AA exposure, AA was administered to 7-week-old male rats via oral gavage at doses of 0, 5, 10, and 20 mg/kg for 28 days. Immunohistochemical analysis revealed that AA decreased the numbers of doublecortin-positive ⁽⁺⁾ cells and polysialic acid-neural cell adhesion molecule⁺ cells in the OB. On the other hand, the numbers of doublecortin⁺ cells and polysialic acid-neural cell adhesion molecule⁺ cells in the SVZ did not change with AA exposure, suggesting that AA impaired neuroblasts migrating in the rostral migratory stream and OB. Gene expression analysis in the OB revealed that AA downregulated Bdnf and Ncam2, which are related to neuronal differentiation and migration. These results suggest that AA decreased neuroblasts in the OB by suppressing neuronal migration. Thus, AA decreased neuronal cell lineages during late-stage differentiation of adult neurogenesis in the OB-SVZ, similar to the effect on adult hippocampal neurogenesis.