Shock Wave Therapy Alleviates Hypoxia/Reoxygenation-Induced Cardiomyocyte Injury by Inhibiting Both Apoptosis and Ferroptosis.

Shock wave therapy (SWT) is a new alternative therapy for patients with severe coronary artery disease that improves myocardial ischemic symptoms by delivering low-energy shock wave stimulation to ischaemic myocardium with low-energy pulsed waves. However, the specific mechanism of its protective effect is not fully understood, especially for the protective mechanism in cardiomyocytes after hypoxia/reoxygenation (H/R). We selected a rat H9c2 cardiomyocyte cell line to establish a stable H/R cardiomyocyte injury model by hypoxia/reoxygenation, and then used SWT for therapeutic intervention to explore its cardiomyocyte protective mechanisms. The results showed that SWT significantly increased cell viability and GSH levels while decreasing LDH levels, ROS levels, and MDA levels. SWT also improved mitochondrial morphology and function of cells after H/R. Meanwhile, we found that SWT could increase the expression of GPX4, xCT, and Bcl-2, while decreasing the expression of Bax and cleaved caspase-3, and inhibiting cardiomyocyte apoptosis and ferroptosis. Moreover, this protective effect of SWT on cardiomyocytes could be significantly reversed by knockdown of xCT, a key regulator protein of ferroptosis. In conclusion, our study shows that SWT can attenuate hypoxia-reoxygenation-induced myocardial injury and protect cardiomyocyte function by inhibiting H/R-induced apoptosis and ferroptosis, and this therapy may have important applications in the treatment of clinical myocardial ischemic diseases.

Inherited mitochondrial dysfunction triggered by OPA1 mutation impacts the sensory innervation fibre identity, functionality and regenerative potential in the cornea.

Mitochondrial dysfunctions are detrimental to organ metabolism. The cornea, transparent outmost layer of the eye, is prone to environmental aggressions, such as UV light, and therefore dependent on adequate mitochondrial function. While several reports have linked corneal defects to mitochondrial dysfunction, the impact of OPA1 mutation, known to induce such dysfunction, has never been studied in this context. We used the mouse line carrying OPA1delTTAG mutation to investigate its impact on corneal biology. To our surprise, neither the tear film composition nor the corneal epithelial transcriptomic signature were altered upon OPA1 mutation. However, when analyzing the corneal innervation, we discovered an undersensitivity of the cornea upon the mutation, but an increased innervation volume at 3 months. Furthermore, the fibre identity changed with a decrease of the SP + axons. Finally, we demonstrated that the innervation regeneration was less efficient and less functional in OPA1+/- corneas. Altogether, our study describes the resilience of the corneal epithelial biology, reflecting the mitohormesis induced by the OPA1 mutation, and the adaptation of the corneal innervation to maintain its functionality despite its morphogenesis defects. These findings will participate to a better understanding of the mitochondrial dysfunction on peripheral innervation.

Progesterone (P4) ameliorates cigarette smoke-induced chronic obstructive pulmonary disease (COPD).

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung disease associated with high morbidity and mortality worldwide. Oxidative injury and mitochondrial dysfunction in the airway epithelium are major events in COPD progression. METHODS AND RESULTS: The therapeutic effects of Progesterone (P4) were investigated in vivo and in vitro in this study. In vivo, in a cigarette smoke (CS) exposure-induced COPD mouse model, P4 treatment significantly ameliorated CS exposure-induced physiological and pathological characteristics, including inflammatory cell infiltration and oxidative injury, in a dose-dependent manner. The c-MYC/SIRT1/PGC-1α pathway is involved in the protective function of P4 against CS-induced COPD. In vitro, P4 co-treatment significantly ameliorated H2O2-induced oxidative injury and mitochondrial dysfunctions by promoting cell proliferation, increasing mitochondrial membrane potential, decreasing ROS levels and apoptosis, and increasing ATP content. Moreover, P4 co-treatment partially attenuated H2O2-caused inhibition in Nrf1, Tfam, Mfn1, PGR-B, c-MYC, SIRT1, and PGC-1α levels. In BEAS-2B and ASM cells, the c-MYC/SIRT1 axis regulated P4's protective effects against H2O2-induced oxidative injury and mitochondrial dysfunctions. CONCLUSION: P4 activates the c-MYC/SIRT1 axis, ameliorating CS-induced COPD and protecting both airway epithelial cells and smooth muscle cells against H2O2-induced oxidative damage. PGC-1α and downstream mitochondrial signaling pathways might be involved.

Hepatoprotective mechanisms of pomegranate bioactives on a murine models affected by NAFLD as analysed by MS-based proteomics: The mitochondria in the eye of the storm.

Deciphering the mechanisms underlying the direct association between fructose consumption and the onset and progression of non-alcoholic fatty liver disease (NAFLD), as well as the high prevalence of metabolic syndrome (MetS), is of great importance for adopting potential nutritional strategies. Thus, an evaluation of the impact of sustained high fructose consumption on the liver physiology of Wistar rats was made. Moreover, the effectiveness of a dietary pomegranate-derived supplement (P) at counteracting fructose-induced liver injury was also assessed. For unveiling the underlying mechanisms, an untargeted proteomic analysis of the livers from nineteen Wistar rats fed on a basal commercial feed and supplemented with either drinking water (C) (n = 6), 30 % (w/v) fructose in drinking water (F) (n = 7) or 30 % (w/v) fructose solution plus 0.2 % (w/v) P (F+P) (n = 6) was assessed. Fructose intake severely increased the abundance of several energy-production related-proteins, such as fructose-bisphosphate aldolase or fatty acid synthase, among others, as well as diminished the amount of another ones, such as carnitine O-palmitoyl transferase or different subunits of acyl-coenzyme A oxidase. These changes could facilitate mitochondrial disturbances and oxidative stress. Regarding the hepatic proteome of F, P extract restored mitochondrial homeostasis and strengthened endogenous antioxidant mechanisms diminishing the amount of proteins involved in process that could increase the oxidative status, as well as increasing both the quantity of several proteins involved in proteasome functionality, as expressing changes in the amount of certain RNA-splicing related-proteins, regarding F proteome.

Alveolar epithelial cells mitigate neutrophilic inflammation in lung injury through regulating mitochondrial fatty acid oxidation.

Type 2 alveolar epithelial (AT2) cells of the lung are fundamental in regulating alveolar inflammation in response to injury. Impaired mitochondrial long-chain fatty acid ß-oxidation (mtLCFAO) in AT2 cells is assumed to aggravate alveolar inflammation in acute lung injury (ALI), yet the importance of mtLCFAO to AT2 cell function needs to be defined. Here we show that expression of carnitine palmitoyltransferase 1a (CPT1a), a mtLCFAO rate limiting enzyme, in AT2 cells is significantly decreased in acute respiratory distress syndrome (ARDS). In mice, Cpt1a deletion in AT2 cells impairs mtLCFAO without reducing ATP production and alters surfactant phospholipid abundance in the alveoli. Impairing mtLCFAO in AT2 cells via deleting either Cpt1a or Acadl (acyl-CoA dehydrogenase long chain) restricts alveolar inflammation in ALI by hindering the production of the neutrophilic chemokine CXCL2 from AT2 cells. This study thus highlights mtLCFAO as immunometabolism to injury in AT2 cells and suggests impaired mtLCFAO in AT2 cells as an anti-inflammatory response in ARDS.

ACAD10 and ACAD11 allow entry of 4-hydroxy fatty acids into ß-oxidation.

Hydroxylated fatty acids are important intermediates in lipid metabolism and signaling. Surprisingly, the metabolism of 4-hydroxy fatty acids remains largely unexplored. We found that both ACAD10 and ACAD11 unite two enzymatic activities to introduce these metabolites into mitochondrial and peroxisomal ß-oxidation, respectively. First, they phosphorylate 4-hydroxyacyl-CoAs via a kinase domain, followed by an elimination of the phosphate to form enoyl-CoAs catalyzed by an acyl-CoA dehydrogenase (ACAD) domain. Studies in knockout cell lines revealed that ACAD10 preferentially metabolizes shorter chain 4-hydroxy fatty acids than ACAD11 (i.e. 6 carbons versus 10 carbons). Yet, recombinant proteins showed comparable activity on the corresponding 4-hydroxyacyl-CoAs. This suggests that the localization of ACAD10 and ACAD11 to mitochondria and peroxisomes, respectively, might influence their physiological substrate spectrum. Interestingly, we observed that ACAD10 is cleaved internally during its maturation generating a C-terminal part consisting of the ACAD domain, and an N-terminal part comprising the kinase domain and a haloacid dehalogenase (HAD) domain. HAD domains often exhibit phosphatase activity, but negligible activity was observed in the case of ACAD10. Yet, inactivation of a presumptive key residue in this domain significantly increased the kinase activity, suggesting that this domain might have acquired a regulatory function to prevent accumulation of the phospho-hydroxyacyl-CoA intermediate. Taken together, our work reveals that 4-hydroxy fatty acids enter mitochondrial and peroxisomal fatty acid ß-oxidation via two enzymes with an overlapping substrate repertoire.

Vitamin D ameliorates particulate matter induced mitochondrial damages and calcium dyshomeostasis in BEAS-2B human bronchial epithelial cells.

BACKGROUND: Mitochondria is prone to oxidative damage by endogenous and exogenous sources of free radicals, including particulate matter (PM). Given the role of mitochondria in inflammatory disorders, such as asthma and chronic obstructive pulmonary disease, we hypothesized that supplementation of vitamin D may play a protective role in PM-induced mitochondrial oxidative damages of human bronchial epithelial BEAS-2B cells. METHODS: BEAS-2B cells were pretreated with 1,25(OH)2D3, an active form of vitamin D, for 1 h prior to 24-hour exposure to PM (SRM-1648a). Oxidative stress was measured by flow cytometry. Mitochondrial functions including mitochondrial membrane potential, ATP levels, and mitochondrial DNA copy number were analyzed. Additionally, mitochondrial ultrastructure was examined using transmission electron microscopy. Intracellular and mitochondrial calcium concentration changes were assessed using flow cytometry based on the expression of Fluo-4 AM and Rhod-2 AM, respectively. Pro-inflammatory cytokines, including IL-6 and MCP-1, were quantified using ELISA. The expression levels of antioxidants, including SOD1, SOD2, CAT, GSH, and NADPH, were determined. RESULTS: Our findings first showed that 24-hour exposure to PM led to the overproduction of reactive oxygen species (ROS) derived from mitochondria. PM-induced mitochondrial oxidation resulted in intracellular calcium accumulation, particularly within mitochondria, and alterations in mitochondrial morphology and functions. These changes included loss of mitochondrial membrane integrity, disarrayed cristae, mitochondrial membrane depolarization, reduced ATP production, and increased mitochondrial DNA copy number. Consequently, PM-induced mitochondrial damage triggered the release of certain inflammatory cytokines, such as IL-6 and MCP-1. Similar to the actions of mitochondrial ROS inhibitor MitoTEMPO, 1,25(OH)2D3 conferred protective effects on mtDNA alterations, mitochondrial damages, calcium dyshomeostasis, thereby decreasing the release of certain inflammatory cytokines. We found that greater cellular level of 1,25(OH)2D3 upregulated the expression of enzymatic (SOD1, SOD2, and CAT) and non-enzymatic (GSH and NADPH) antioxidants to modulate cellular redox homeostasis. CONCLUSION: Our study provides new evidence that 1,25(OH)2D3 acts as an antioxidant, enhancing BEAS-2B antioxidant responses to regulate mitochondrial ROS homeostasis and mitochondrial function, thereby enhancing epithelial defense against air pollution exposure.

ML335 inhibits TWIK2 channel-mediated potassium efflux and attenuates mitochondrial damage in MSU crystal-induced inflammation.

BACKGROUND: Activation of the NLRP3 inflammasome is critical in the inflammatory response to gout. Potassium ion (K+) efflux mediated by the TWIK2 channel is an important upstream mechanism for NLRP3 inflammasome activation. Therefore, the TWIK2 channel may be a promising therapeutic target for MSU crystal-induced inflammation. In the present study, we investigated the effect of ML335, a known K2P channel modulator, on MSU crystal-induced inflammatory responses and its underlying molecular mechanisms. METHODS: By molecular docking, we calculated the binding energies and inhibition constants of five K2P channel modulators (Hydroxychloroquine, Fluoxetine, DCPIB, ML365 and ML335) with TWIK2. Intracellular potassium ion concentration and mitochondrial function were assessed by flow cytometry. The interaction between MARCH5 and SIRT3 was demonstrated by immunoprecipitation and Western blotting assay. MSU suspensions were injected into mouse paw and peritoneal cavity to induce acute gout model. RESULTS: ML335 has the highest binding energy and the lowest inhibition constant with TWIK2 in the five calculated K2P channel modulators. In comparison, among these five compounds, ML335 efficiently inhibited the release of IL-1ß from MSU crystal-treated BMDMs. ML335 decreased MSU crystal-induced K+ efflux mainly dependent on TWIK2 channel. More importantly, ML335 can effectively inhibit the expression of the mitochondrial E3 ubiquitin ligase MARCH5 induced by MSU crystals, and MARCH5 can interact with the SIRT3 protein. ML335 blocked MSU crystal-induced ubiquitination of SIRT3 protein by MARCH5. In addition, ML335 improved mitochondrial dynamics homeostasis and mitochondrial function by inhibiting MARCH5 protein expression. ML335 attenuated the inflammatory response induced by MSU crystals in vivo and in vitro. CONCLUSION: Inhibition of TWIK2-mediated K+ efflux by ML335 alleviated mitochondrial injury via suppressing March5 expression, suggesting that ML335 may be an effective candidate for the future treatment of gout.

Queuine ameliorates impaired mitochondrial function caused by mt-tRNAAsn variants.

BACKGROUND: Mitochondrial tRNA (mt-tRNA) variants have been found to cause disease. Post-transcriptional queuosine (Q) modifications of mt-tRNA can promote efficient mitochondrial mRNA translation. Q modifications of mt-tRNAAsn have recently been identified. Here, the therapeutic effectiveness of queuine was investigated in cells from patients with mt-tRNAAsn variants. METHODS: Six patients (from four families) carrying mt-tRNAAsn variants were included in the study. Queuine levels were quantified by mass spectrometry. Clinical, genetic, histochemical, biochemical, and molecular analysis was performed on muscle tissues and lymphoblastoid cell lines (LCLs) from patients to investigate the pathogenicity of the novel m.5708 C > T variant. The use of queuine in mitigating mitochondrial dysfunction resulting from the mt-tRNAAsn variants was evaluated. RESULTS: The variants included the m.5701 delA, m.5708 C > T, m.5709 C > T, and m.5698 G > A variants in mt-tRNAAsn. The pathogenicity of the novel m.5708 C > T variant was confirmed, as demonstrated by a decreased steady-state level of mt-tRNAAsn, mtDNA-encoded protein levels, oxygen consumption rate (OCR), and the respiratory complex activity. Notably, the serum queuine level was significantly reduced in these patients and in vitro queuine supplementation was found to restore the reductions in mitochondrial protein activities, mitochondrial membrane potential, OCR, and increases in reactive oxygen species. CONCLUSIONS: The study not only confirmed the pathogenicity of the m.5708 C > T variant but also explored the therapeutic potential of queuine in individuals with mt-tRNAAsn variants. The recognition of the novel m.5708 C > T variant's pathogenic nature contributes to our comprehension of mitochondrial disorders. Furthermore, the results emphasize queuine supplementation as a promising approach to enhance the stability of mt-tRNAAsn and rescue mitochondrial dysfunction caused by mt-tRNAAsn variants, indicating potential implications for the development of targeted therapies for patients with mt-tRNAAsn variants.

Exploring the prognostic landscape of oral squamous cell carcinoma through mitochondrial damage-related genes.

Oral squamous cell carcinoma (OSCC), the most prevalent form of oral cancer, poses significant challenges to the medical community due to its high recurrence rate and low survival rate. Mitochondrial Damage-Related Genes (MDGs) have been closely associated with the occurrence, metastasis, and progression of OSCC. Consequently, we constructed a prognostic model for OSCC based on MDGs and identified potential mitochondrial damage-related biomarkers. Gene expression profiles and relevant clinical information were obtained from The Cancer Genome Atlas (TCGA) database. Differential analysis was conducted to identify MDGs associated with OSCC. COX analysis was employed to screen seven prognosis-related MDGs and build a prognostic prediction model for OSCC. Cases were categorized into low-risk or high-risk groups based on the optimal risk score threshold. Kaplan-Meier (KM) analysis revealed significant survival differences (P < 0.05). Additionally, the area under the ROC curve (AUC) for patient survival at 1 year, 3 years, and 5 years were 0.687, 0.704, and 0.70, respectively, indicating a high long-term predictive accuracy of the prognostic model. To enhance predictive accuracy, age, gender, risk score, and TN staging were incorporated into a nomogram and verified using calibration curves. Risk scoring based on MDGs was identified as a potential independent prognostic biomarker. Furthermore, BID and SLC25A20 were identified as two potential independent mitochondrial damage-related prognostic biomarkers, offering new therapeutic targets for OSCC.

Avermectin induced vascular damage in zebrafish larvae: association with mitochondria-mediated apoptosis and VEGF/Notch signaling pathway.

Avermectin is a highly effective insecticide that has been widely used in agriculture since the 1990s. In recent years, the safety of avermectin for non-target organisms has received much attention. The vasculature is important organs in the body and participate in the composition of other organs. However, studies on the vascular safety of avermectin are lacking. The vasculature of zebrafish larvae is characterized by ease of observation and it is a commonly used model for vascular studies. Therefore, zebrafish larvae were used to explore the potential risk of avermectin on the vasculature. The results showed that avermectin induced vascular damage throughout the body of zebrafish larvae, including the head, eyes, intestine, somite, tail and other vasculature. The main forms of damage are reduction in vascular diameter, vascular area and vascular abundance. Meanwhile, avermectin induced a decrease in the number of endothelial cells and apoptosis within the vasculature. In addition, vascular damage may be related to impairment of mitochondrial function and mitochondria-mediated apoptosis. Finally, exploration of the molecular mechanisms revealed abnormal alterations in the expression of genes related to the VEGF/Notch signaling pathway. Therefore, the VEGF/Notch signaling pathway may be an important mechanism for avermectin-induced vascular damage in zebrafish larvae. This study demonstrates the vascular toxicity of avermectin in zebrafish larvae and reveals the possible molecular mechanism, which would hopefully draw more attention to the safety of avermectin in non-target organisms.

The cytokine Meteorin-like inhibits anti-tumor CD8+ T cell responses by disrupting mitochondrial function.

Tumor-infiltrating lymphocyte (TIL) hypofunction contributes to the progression of advanced cancers and is a frequent target of immunotherapy. Emerging evidence indicates that metabolic insufficiency drives T cell hypofunction during tonic stimulation, but the signals that initiate metabolic reprogramming in this context are largely unknown. Here, we found that Meteorin-like (METRNL), a metabolically active cytokine secreted by immune cells in the tumor microenvironment (TME), induced bioenergetic failure of CD8+ T cells. METRNL was secreted by CD8+ T cells during repeated stimulation and acted via both autocrine and paracrine signaling. Mechanistically, METRNL increased E2F-peroxisome proliferator-activated receptor delta (PPARδ) activity, causing mitochondrial depolarization and decreased oxidative phosphorylation, which triggered a compensatory bioenergetic shift to glycolysis. Metrnl ablation or downregulation improved the metabolic fitness of CD8+ T cells and enhanced tumor control in several tumor models, demonstrating the translational potential of targeting the METRNL-E2F-PPARδ pathway to support bioenergetic fitness of CD8+ TILs.

Pulsed electromagnetic fields regulate metabolic reprogramming and mitochondrial fission in endothelial cells for angiogenesis.

Pulsed electromagnetic field (PEMF) therapy has been extensively investigated in clinical studies for the treatment of angiogenesis-related diseases. However, there is a lack of research on the impact of PEMFs on energy metabolism and mitochondrial dynamics during angiogenesis. The present study included tube formation and CCK-8 assays. A Seahorse assay was conducted to analyze energy metabolism, and mitochondrial membrane potential assays, mitochondrial imaging, and reactive oxygen species assays were used to measure changes in mitochondrial structure and function in human umbilical vein endothelial cells (HUVECs) exposed to PEMFs. Real-time polymerase chain reaction was used to analyze the mRNA expression levels of antioxidants, glycolytic pathway-related genes, and genes associated with mitochondrial fission and fusion. The tube formation assay demonstrated a significantly greater tube network in the PEMF group compared to the control group. The glycolysis and mitochondrial stress tests revealed that PEMFs promoted a shift in the energy metabolism pattern of HUVECs from oxidative phosphorylation to aerobic glycolysis. Mitochondrial imaging revealed a wire-like mitochondrial morphology in the control group, and treatment with PEMFs led to shorter and more granular mitochondria. Our major findings indicate that exposure to PEMFs accelerates angiogenesis in HUVECs, likely by inducing energy metabolism reprogramming and mitochondrial fission.

Granulosa cell insight: unraveling the potential of menstrual blood-derived stem cells and their exosomes on mitochondrial mechanisms in polycystic ovary syndrome (PCOS).

BACKGROUND: Polycystic ovary syndrome (PCOS) presents a significant challenge in women's reproductive health, characterized by disrupted folliculogenesis and ovulatory dysfunction. Central to PCOS pathogenesis are granulosa cells, whose dysfunction contributes to aberrant steroid hormone production and oxidative stress. Mitochondrial dysfunction emerges as a key player, influencing cellular energetics, oxidative stress, and steroidogenesis. This study investigates the therapeutic potential of menstrual blood-derived stem cells (MenSCs) and their exosomes in mitigating mitochondrial dysfunction and oxidative stress in PCOS granulosa cells. METHODS: Using a rat model of PCOS induced by letrozole, granulosa cells were harvested and cultured. MenSCs and their exosomes were employed to assess their effects on mitochondrial biogenesis, oxidative stress, and estrogen production in PCOS granulosa cells. RESULTS: Results showed diminished mitochondrial biogenesis and increased oxidative stress in PCOS granulosa cells, alongside reduced estrogen production. Treatment with MenSCs and their exosomes demonstrated significant improvements in mitochondrial biogenesis, oxidative stress levels, and estrogen production in PCOS granulosa cells. Further analysis showed MenSCs' superior efficacy over exosomes, attributed to their sustained secretion of bioactive factors. Mechanistically, MenSCs and exosomes activated pathways related to mitochondrial biogenesis and antioxidative defense, highlighting their therapeutic potential for PCOS. CONCLUSIONS: This study offers insights into granulosa cells mitochondria's role in PCOS pathogenesis and proposes MenSCs and exosomes as a potential strategy for mitigating mitochondrial dysfunction and oxidative stress in PCOS. Further research is needed to understand underlying mechanisms and validate clinical efficacy, presenting promising avenues for addressing PCOS complexity.

Hypoxia-induced downregulation of PGK1 crotonylation promotes tumorigenesis by coordinating glycolysis and the TCA cycle.

Protein post-translational modifications (PTMs) are crucial for cancer cells to adapt to hypoxia; however, the functional significance of lysine crotonylation (Kcr) in hypoxia remains unclear. Herein we report a quantitative proteomics analysis of global crotonylome under normoxia and hypoxia, and demonstrate 128 Kcr site alterations across 101 proteins in MDA-MB231 cells. Specifically, we observe a significant decrease in K131cr, K156cr and K220cr of phosphoglycerate kinase 1 (PGK1) upon hypoxia. Enoyl-CoA hydratase 1 (ECHS1) is upregulated and interacts with PGK1, leading to the downregulation of PGK1 Kcr under hypoxia. Abolishment of PGK1 Kcr promotes glycolysis and suppresses mitochondrial pyruvate metabolism by activating pyruvate dehydrogenase kinase 1 (PDHK1). A low PGK1 K131cr level is correlated with malignancy and poor prognosis of breast cancer. Our findings show that PGK1 Kcr is a signal in coordinating glycolysis and the tricarboxylic acid (TCA) cycle and may serve as a diagnostic indicator for breast cancer.

Defective mitochondrial COX1 translation due to loss of COX14 function triggers ROS-induced inflammation in mouse liver.

Mitochondrial oxidative phosphorylation (OXPHOS) fuels cellular ATP demands. OXPHOS defects lead to severe human disorders with unexplained tissue specific pathologies. Mitochondrial gene expression is essential for OXPHOS biogenesis since core subunits of the complexes are mitochondrial-encoded. COX14 is required for translation of COX1, the central mitochondrial-encoded subunit of complex IV. Here we describe a COX14 mutant mouse corresponding to a patient with complex IV deficiency. COX14M19I mice display broad tissue-specific pathologies. A hallmark phenotype is severe liver inflammation linked to release of mitochondrial RNA into the cytosol sensed by RIG-1 pathway. We find that mitochondrial RNA release is triggered by increased reactive oxygen species production in the deficiency of complex IV. Additionally, we describe a COA3Y72C mouse, affected in an assembly factor that cooperates with COX14 in early COX1 biogenesis, which displays a similar yet milder inflammatory phenotype. Our study provides insight into a link between defective mitochondrial gene expression and tissue-specific inflammation.

NR4A ablation improves mitochondrial fitness for long persistence in human CAR-T cells against solid tumors.

BACKGROUND: Antitumor effect of chimeric antigen receptor (CAR)-T cells against solid tumors is limited due to various factors, such as low infiltration rate, poor expansion capacity, and exhaustion of T cells within the tumor. NR4A transcription factors have been shown to play important roles in T-cell exhaustion in mice. However, the precise contribution of each NR4a factor to human T-cell differentiation remains to be clarified. METHODS: In this study, we deleted NR4A family factors, NR4A1, NR4A2, and NR4A3, in human CAR-T cells recognizing human epidermal growth factor receptor type 2 (HER2) by using the CRISPR/Cas9 system. We induced T-cell exhaustion in these cells in vitro through repeated co-culturing of CAR-T cells with Her2+A549 lung adenocarcinoma cells and evaluated cell surface markers such as memory and exhaustion phenotypes, proliferative capacity, cytokine production and metabolic activity. We validated the antitumor toxicity of NR4A1/2/3 triple knockout (TKO) CAR-T cells in vivo by transferring CAR-T cells into A549 tumor-bearing immunodeficient mice. RESULTS: Human NR4A-TKO CAR-T cells were resistant against exhaustion induced by repeated antigen stimulation in vitro, and maintained higher tumor-killing activity both in vitro and in vivo compared with control CAR-T cells. A comparison of the effectiveness of NR4A single, double, and TKOs demonstrated that triple KO was the most effective in avoiding exhaustion. Furthermore, a strong enhancement of antitumor effects by NR4A TKO was also observed in T cells from various donors including aged persons. Mechanistically, NR4A TKO CAR-T cells showed enhanced mitochondrial oxidative phosphorylation, therefore could persist for longer periods within the tumors. CONCLUSIONS: NR4A factors regulate CAR-T cell persistence and stemness through mitochondrial gene expression, therefore NR4A is a highly promising target for the generation of superior CAR-T cells against solid tumors.

Ferulic acid restores mitochondrial dynamics and autophagy via AMPK signaling pathway in a palmitate-induced hepatocyte model of metabolic syndrome.

Mitochondrial dysfunction, characterized by elevated oxidative stress, impaired energy balance, and dysregulated mitochondrial dynamics, is a hallmark of metabolic syndrome (MetS) and its comorbidities. Ferulic acid (FA), a principal phenolic compound found in whole grains, has demonstrated potential in ameliorating oxidative stress and preserving energy homeostasis. However, the influence of FA on mitochondrial health within the context of MetS remains unexplored. Moreover, the impact of FA on autophagy, which is essential for maintaining energy homeostasis and mitochondrial integrity, is not fully understood. Here, we aimed to study the mechanisms of action of FA in regulating mitochondrial health and autophagy using palmitate-treated HepG2 hepatocytes as a MetS cell model. We found that FA improved mitochondrial health by restoring redox balance and optimizing mitochondrial dynamics, including biogenesis and the fusion/fission ratio. Additionally, FA was shown to recover autophagy and activate AMPK-related cell signaling. Our results provide new insights into the therapeutic potential of FA as a mitochondria-targeting agent for the prevention and treatment of MetS.

hUMSCs restore ovarian function in POI mice by regulating GSK3ß-mediated mitochondrial dynamic imbalances in theca cells.

Premature ovarian insufficiency (POI), a major cause of female infertility, is defined as follicular atresia and a rapid loss of germ cells in women of reproductive age due to ovarian failure. Recently, findings from several studies have indicated that human umbilical cord mesenchymal stem cells (hUMSCs) can alleviate ovarian dysfunction resulting from POI. However, the mechanisms underlying this effect require further clarification. In this study, a mouse model of POI was established as achieved with an intraperitoneal injection of cyclophosphamide (CTX) into female C57BL/6J mice in vivo. These POI mice received a 1-week intervention of hUMACs. In addition, an in vitro POI model was also included. The cultured supernatants of hUMSCs and glycogen synthase kinase 3 beta (GSK3ß) inhibitor (SB216763) were used to treat theca cells (TCs) exposed to CTX. Hematoxylin and Eosin (H&E) staining and Enzyme-linked immunosorbent assay (ELISA) were used to assess ovarian structure and morphology, as well as endocrine function in these POI mice. Based on results from the ELISA and JC-1 labeling, CTX exerted significant detrimental effects on testosterone levels and the mitochondrial membrane potential in TCs. Subsequently, Western Blot, Immunofluorescence staining (IF), and Quantitative real-time polymerase chain reaction (qRT-PCR) were used to evaluate various indicators of testosterone synthesis function and mitochondrial dynamics in ovaries and TCs of POI mice. In vivo, dysfunctions in ovarian structure and function in the POI mouse model were effectively restored following hUMSCs treatment, and abnormalities in hormone synthesis were significantly reduced. Furthermore, when the stem cell supernatants of hUMSCs were applied to TCs in vitro we found that GSK3ß expression was reduced, the imbalance of mitochondrial dynamics was alleviated, and the ability of mitochondrial testosterone synthesis was increased. Taken together, our results indicate that hUMSCs treatment can restore the imbalance of mitochondrial dynamics and restart testosterone synthesis of TCs by suppressing GSK3ß expression, ultimately alleviating POI damage.