Hypoxemia is a common pathological state characterized by low oxygen saturation in the blood. This condition compromises mucosal barrier integrity particularly in the gut and oral cavity. However, the mechanisms underlying this association remain unclear. This study used periodontitis as a model to investigate the role of platelet activation in oral mucosal immunopathology under hypoxic conditions. Hypoxia upregulated methyltransferase-like protein 4 (METTL4) expression in platelets, resulting in N⁶-methyladenine modification of mitochondrial DNA (mtDNA). This modification impaired mitochondrial transcriptional factor A-dependent cytosolic mtDNA degradation, leading to cytosolic mtDNA accumulation. Excess cytosolic mt-DNA aberrantly activated the cGAS-STING pathway in platelets. This resulted in excessive platelet activation and neutrophil extracellular trap formation that ultimately exacerbated periodontitis. Targeting platelet METTL4 and its downstream pathways offers a potential strategy for managing oral mucosa immunopathology. Further research is needed to examine its broader implications for mucosal inflammation under hypoxic conditions.
DNA, Mitochondrial/metabolism* ; Mouth Mucosa/pathology* ; Hypoxia/immunology* ; Methyltransferases/metabolism* ; Blood Platelets/metabolism* ; Animals ; Periodontitis/immunology* ; Humans ; Platelet Activation ; Mice

Patients with severe pneumonia caused by novel coronavirus infection are often complicated with acute respiratory distress syndrome (ARDS), which has a high mortality. ARDS is characterized by diffuse alveolar damage, pulmonary edema, and hypoxemia. Mitochondria are prone to morphological and functional abnormalities under hypoxia and viral infection, which can lead to cell apoptosis and damage, severely impacting the disease progression. Mitochondria maintain homeostasis through fission and fusion. In ARDS, hypoxia leads to the phosphorylation of dynamin-related protein 1 (Drp1), triggering excessive mitochondrial fission and damaging the alveolar epithelial barrier. Animal experiments have shown that inhibiting this process can alleviate lung injury, providing a potential direction for treatment. The pathology of novel coronavirus infection-related ARDS is similar to that of typical ARDS but more severe. Viral infection and hypoxia disrupt the mitochondrial balance, causing fission and autophagy abnormalities, promoting oxidative stress and mitochondrial DNA (mtDNA) release, activating inflammasomes, inducing the expression of hypoxia-inducible factor-1α (HIF-1α), exacerbating viral infection, inflammation, and coagulation reactions, and resulting in multiple organ damage. Mechanical ventilation and glucocorticoids are commonly used in the treatment of novel coronavirus infection-related ARDS. Mechanical ventilation is likely to cause lung and diaphragm injuries and changes in mitochondrial dynamics, while the lung protective ventilation strategy can reduce the adverse effects. Glucocorticoids can regulate mitochondrial function and immune response and improve the patient's condition through multiple pathways. The mitochondrial dynamics imbalance in novel coronavirus infection-related ARDS is caused by hypoxia and viral proteins, leading to lung and multiple organ injuries. To clarify the pathophysiological mechanism of mitochondrial dynamics imbalance in novel coronavirus infection-related ARDS and explore effective strategies for regulating mitochondrial dynamics balance to treat this disease, so as to provide new treatment targets and methods for patients with novel coronavirus infection-related ARDS. The existing treatments have limitations. Future research needs to deeply study the mechanism of mitochondrial dysfunction, develop new therapies and regulatory strategies, and improve the treatment effect.
Humans ; Respiratory Distress Syndrome/etiology* ; COVID-19 ; Mitochondrial Dynamics ; Mitochondria/metabolism* ; DNA, Mitochondrial ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Dynamins ; SARS-CoV-2

OBJECTIVES: To explore the mechanism by which Wiskott-Aldrich syndrome protein family verprolin-homologous protein 1 (WAVE1) regulates lipopolysaccharide (LPS)-induced mitochondrial metabolic abnormalities and inflammatory responses in macrophages. METHODS: Macrophage cell lines with overexpressed WAVE1 (mouse BMDM and human THP1 cells) were prepared. The macrophages were treated with LPS (500 ng/mL) to simulate sepsis-induced inflammatory responses. The experiment consisted of two parts. The first part included control, LPS, vector (LPS+oe-NC), WAVE1 overexpression (LPS+oe-WAVE1) groups. The second part included LPS, LPS+oe-NC, LPS+oe-WAVE1 and exogenous high mobility group box-1 (HMGB1) intervention (LPS+oe-WAVE1+HMGB1) groups. RT-PCR was used to measure mitochondrial DNA content, and RT-qPCR was used to detect the mRNA expression levels of WAVE1, tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6. Western blot was performed to measure the protein expression of WAVE1, hexokinase 2, and pyruvate kinase M2. ELISA was utilized to detect the levels of TNF-α, IL-1β, IL-6, and HMGB1. JC-1 staining was used to assess mitochondrial membrane potential. Seahorse XP96 was used to evaluate oxygen consumption rate and extracellular acidification rate. MitoSOX probe was employed to measure mitochondrial reactive oxygen species levels, and 2-NBDG method was used to assess glucose uptake. Kits were used to measure pyruvate kinase activity, lactate, adenosine triphosphate (ATP), and HMGB1 levels. RESULTS: Compared with the control group, the LPS group showed lower levels of WAVE1 protein and mRNA expression, mitochondrial membrane potential, oxygen consumption rate, and mitochondrial DNA content (P<0.05), while TNF-α, IL-1β, IL-6 levels and mRNA expression, mitochondrial reactive oxygen species, glucose uptake, lactate, ATP, hexokinase 2, and pyruvate kinase M2 protein expression levels as well as extracellular acidification rate, pyruvate kinase activity, and HMGB1 release were significantly increased (P<0.05). Compared with the LPS+oe-NC group, the LPS+oe-WAVE1 group showed increased WAVE1 protein and mRNA expression, mitochondrial membrane potential, oxygen consumption rate, and mitochondrial DNA content (P<0.05), while TNF-α, IL-1β, IL-6 levels and mRNA expression, mitochondrial reactive oxygen species, glucose uptake, lactate, ATP, hexokinase 2, and pyruvate kinase M2 protein expressions, as well as extracellular acidification rate, pyruvate kinase activity, and HMGB1 release were decreased (P<0.05). Compared with the LPS+oe-WAVE1 group, the LPS+oe-WAVE1+HMGB1 group exhibited increased glucose uptake, lactate, ATP levels, and extracellular acidification rate (P<0.05). CONCLUSIONS WAVE1 participates in the regulation of LPS-induced inflammatory responses in macrophages by modulating the release of inflammatory factors, mitochondrial metabolism, and HMGB1 release.
Lipopolysaccharides ; Humans ; Mitochondria/metabolism* ; Animals ; Macrophages/metabolism* ; Mice ; Hexokinase/genetics* ; Wiskott-Aldrich Syndrome Protein Family/metabolism* ; HMGB1 Protein/physiology* ; Inflammation/metabolism* ; DNA, Mitochondrial ; Pyruvate Kinase/metabolism*

Oral potentially malignant disorders (OPMDs) are precursors of oral squamous cell carcinoma (OSCC). Deregulated cellular energy metabolism is a critical hallmark of cancer cells. Peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC1α) plays vital role in mitochondrial energy metabolism. However, the molecular mechanism of PGC1α on OPMDs progression is less unclear. Therefore, we investigated the effects of knockdown PGC1α on human dysplastic oral keratinocytes (DOKs) comprehensively, including cell proliferation, cell cycle, apoptosis, xenograft tumor, mitochondrial DNA (mtDNA), mitochondrial electron transport chain complexes (ETC), reactive oxygen species (ROS), oxygen consumption rate (OCR), extracellular acidification rate (ECAR), and glucose uptake. We found that knockdown PGC1α significantly inhibited the proliferation of DOKs in vitro and tumor growth in vivo, induced S-phase arrest, and suppressed PI3K/Akt signaling pathway without affecting cell apoptosis. Mechanistically, downregulated of PGC1α decreased mtDNA, ETC, and OCR, while enhancing ROS, glucose uptake, ECAR, and glycolysis by regulating lactate dehydrogenase A (LDHA). Moreover, SR18292 (an inhibitor of PGC1α) induced oxidative phosphorylation dysfunction of DOKs and declined DOK xenograft tumor progression. Thus, our work suggests that PGC1α plays a crucial role in cell proliferation by reprograming energy metabolism and interfering with energy metabolism, acting as a potential therapeutic target for OPMDs.
Humans ; Carcinoma, Squamous Cell/metabolism* ; Cell Proliferation ; DNA, Mitochondrial ; Energy Metabolism ; Glucose ; Mouth Neoplasms/metabolism* ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha/metabolism* ; Phosphatidylinositol 3-Kinases ; Reactive Oxygen Species

Mitochondrial DNA is the mitochondria's own genetic material located within the mitochondrial matrix and is involved in cellular metabolism and energy supply. Mitochondrial DNA damage exacerbates oxidative stress by increasing the release of reactive oxygen species, while mitochondrial DNA release also triggers apoptosis and activates immune inflammatory responses through damage-related molecular patterns. Mitochondrial autophagy regulates mitochondrial DNA damage and release through a negative feedback mechanism to maintain intracellular homeostasis. Recent studies have shown that the occurrence and development of chronic liver disease are closely related to mitochondrial DNA-mediated immune inflammatory responses and oxidative stress.
Apoptosis ; Autophagy ; DNA, Mitochondrial/metabolism* ; Humans ; Liver Diseases ; Mitochondria ; Oxidative Stress ; Reactive Oxygen Species/metabolism*

OBJECTIVE: To explore the genetic etiology of a Chinese pedigree affected with infantile hepatitis syndrome. METHODS: Genes associated with liver diseases subjected to high-throughput sequencing. Candidate variants were validated by Sanger sequencing of the proband and his parents. The pathogenicity of the variants was analyzed through bioinformatic analysis. RESULTS: High-throughput sequencing revealed that the proband has harbored c.182T>C (p.F61S) and c.293C>T (p.P98L) variants of the MPV17 gene, which were verified by Sanger sequencing to be inherited from his parents. The variant c.182T>C (p.F61S) was unreported previously and predicted to be likely pathogenic by bioinformatic analysis. CONCLUSION The proband was caused by the compound heterozygous variations of MPV17 gene including c.182T>C (p.F61S) and c.293C>T (p.P98L). Discovery of the novel variant has enriched the spectrum of pathogenic variants of the MPV17 gene.
China ; DNA, Mitochondrial/genetics* ; Female ; Genetic Testing ; Humans ; Membrane Proteins/genetics* ; Metabolism, Inborn Errors/genetics* ; Mitochondrial Proteins/genetics* ; Mutation ; Pedigree ; Pregnancy ; Prenatal Diagnosis ; Syndrome

Osteoarthritis (OA) is a degenerative articular disorder manifested by cartilage destruction, subchondral sclerosis, osteophytes, and synovitis, resulting in chronic joint pain and physical disability in the elderly. The purpose of this study was to investigate mitochondrial DNA copy number (mtDNA_CN) and inflammatory cytokines in primary knee OA patients and healthy volunteers. A total of 204 knee OA patients and 169 age-matched healthy volunteers were recruited. Their relative blood leukocyte mtDNA_CN was assessed by quantitative real-time polymerase chain reaction (qRT-PCR), and ten inflammatory cytokines in their plasma were detected by multiplex immunoassay. Blood leukocyte mtDNA_CN in the OA group was significantly lower than that in the control group. Leukocyte mtDNA_CN in the control group was negatively correlated with their age (r=-0.380, P<0.0001), whereas mtDNA_CN in the OA group was positively correlated with their age (r=0.198, P<0.001). Plasma interleukin-4 (IL-4) and IL-6 were significantly higher in the knee OA group than in the control group. The plasma IL-6 level was positively correlated with blood leukocyte mtDNA_CN in the OA group (r=0.547, P=0.0014). IL-5 showed as a major factor (coefficient 0.69) in the second dimension of principle components analysis (PCA)-transformed data and was significantly higher in the OA group (P<0.001) as well as negatively correlated with mtDNA_CN (r=-0.577, P<0.001). These findings suggest that elevation of plasma IL-4 and IL-6 and a relative reduction in mtDNA_CN might be effective biomarkers for knee OA. IL-5 is a plausible factor responsible for decreasing blood leukocyte mtDNA_CN in knee OA patients.
Age Factors ; Aged ; Aged, 80 and over ; Cytokines/blood* ; DNA, Mitochondrial/blood* ; Female ; Gene Dosage ; Humans ; Leukocytes/metabolism* ; Male ; Middle Aged ; Osteoarthritis, Knee/metabolism* ; Principal Component Analysis

Ageratina adenophora is a noxious plant and it is known to cause acute asthma, diarrhea, depilation, and even death in livestock (Zhu et al., 2007; Wang et al., 2017). A. adenophora grows near roadsides and degraded land worldwide (He et al., 2015b). In the areas where it grows, A. adenophora is an invasive species that inhibits the growth of local plants and causes poisoning in animals that come in contact with it (Nie et al., 2012). In China, these plants can be found in Yunnan, Sichuan, Guizhou, Chongqing, and other southwestern areas (He et al., 2015a) and they have become a dominant species in these local regions. It threatens the native biodiversity and ecosystem in the invaded areas and causes serious economic losses (Wang et al., 2017). It has been reported that A. adenophora can grow in the northeast direction at a speed of 20 km per year in China (Guo et al., 2009). Because of the damage caused by A. adenophora, it ranks among the earliest alien invasive plant species in China (Wang et al., 2017).
Adenosine Triphosphatases/metabolism* ; Ageratina/toxicity* ; Animals ; Biodiversity ; Chemical and Drug Induced Liver Injury/pathology* ; China ; DNA, Mitochondrial/genetics* ; Ecosystem ; Introduced Species ; Liver/drug effects* ; Mice ; Microscopy, Electron, Transmission ; Mitochondria, Liver/pathology* ; Plant Extracts/toxicity*

Mitochondrial diseases are maternally inherited heterogeneous disorders that are primarily caused by mitochondrial DNA (mtDNA) mutations. Depending on the ratio of mutant to wild-type mtDNA, known as heteroplasmy, mitochondrial defects can result in a wide spectrum of clinical manifestations. Mitochondria-targeted endonucleases provide an alternative avenue for treating mitochondrial disorders via targeted destruction of the mutant mtDNA and induction of heteroplasmic shifting. Here, we generated mitochondrial disease patient-specific induced pluripotent stem cells (MiPSCs) that harbored a high proportion of m.3243A>G mtDNA mutations and caused mitochondrial encephalomyopathy and stroke-like episodes (MELAS). We engineered mitochondrial-targeted transcription activator-like effector nucleases (mitoTALENs) and successfully eliminated the m.3243A>G mutation in MiPSCs. Off-target mutagenesis was not detected in the targeted MiPSC clones. Utilizing a dual fluorescence iPSC reporter cell line expressing a 3243G mutant mtDNA sequence in the nuclear genome, mitoTALENs displayed a significantly limited ability to target the nuclear genome compared with nuclear-localized TALENs. Moreover, genetically rescued MiPSCs displayed normal mitochondrial respiration and energy production. Moreover, neuronal progenitor cells differentiated from the rescued MiPSCs also demonstrated normal metabolic profiles. Furthermore, we successfully achieved reduction in the human m.3243A>G mtDNA mutation in porcine oocytes via injection of mitoTALEN mRNA. Our study shows the great potential for using mitoTALENs for specific targeting of mutant mtDNA both in iPSCs and mammalian oocytes, which not only provides a new avenue for studying mitochondrial biology and disease but also suggests a potential therapeutic approach for the treatment of mitochondrial disease, as well as the prevention of germline transmission of mutant mtDNA.
Animals ; DNA, Mitochondrial ; genetics ; Humans ; Induced Pluripotent Stem Cells ; cytology ; metabolism ; MELAS Syndrome ; genetics ; Male ; Mice ; Microsatellite Repeats ; genetics ; Mitochondria ; genetics ; metabolism ; Mutation ; genetics

Despite overall reductions in heart disease prevalence, the risk of developing heart failure has remained 2-fold greater among people with diabetes. Growing evidence has supported that fluctuations in glucose level and uptake contribute to cardiovascular disease (CVD) by modifying proteins, DNA, and gene expression. In the case of glucose, clinical studies have shown that increased dietary sugars for healthy individuals or poor glycemic control in diabetic patients further increased CVD risk. Furthermore, even after decades of maintaining tight glycemic control, susceptibility to disease progression can persist following a period of poor glycemic control through a process termed "glycemic memory." In response to chronically elevated glucose levels, a number of studies have identified molecular targets of the glucose-mediated protein posttranslational modification by the addition of an O-linked N-acetylglucosamine to impair contractility, calcium sensitivity, and mitochondrial protein function. Additionally, elevated glucose contributes to dysfunction in coupling glycolysis to glucose oxidation, pentose phosphate pathway, and polyol pathway. Therefore, in the "sweetened" environment associated with hyperglycemia, there are a number of pathways contributing to increased susceptibly to "breaking" the heart of diabetics. In this review we will discuss the unique contribution of glucose to heart disease and recent advances in defining mechanisms of action.
Calcium ; Cardiomyopathies ; Cardiovascular Diseases ; Diabetic Cardiomyopathies* ; Dietary Sucrose ; Disease Progression ; DNA ; Gene Expression ; Glucose* ; Glycolysis ; Heart ; Heart Diseases ; Heart Failure ; Humans ; Hyperglycemia ; Metabolism ; Mitochondrial Proteins ; Pentose Phosphate Pathway ; Prevalence ; Protein Processing, Post-Translational