Increased levels of circulating oxidized mitochondrial DNA contribute to chronic inflammation in metabolic syndrome, and MitoQ-based antioxidant therapy alleviates this DNA-induced inflammation

Mitoquinol improves phagocytosis and glycolysis in ethanol-exposed macrophages via HIF-1α-PFKP axis

Alcohol use disorder increases sepsis mortality. Acute ethanol exposure impairs pathogen clearance in the macrophages via dampened glycolysis and phagocytosis, exaggerates oxidative stress, and regulates the function of the hypoxia-regulating factor 1α (HIF-1α), a master regulator of glycolysis. Decreased expression of the platelet isoform of phosphofructokinase (PFKP), a key glycolytic enzyme, in ethanol-exposed macrophages, is reported. However, transcriptional regulation of PFKP with ethanol exposure is unclear. We hypothesized that acute ethanol exposure-induced oxidative stress dampens macrophage phagocytosis and glycolysis via the HIF-1α-PFKP axis. In ethanol-exposed mouse bone marrow-derived macrophages with lipopolysaccharide stimulation, we studied (i) reactive oxygen species (ROS), phagocytosis, glycolysis, PFKP, and HIF-1α expressions ± ethanol exposure; (ii) the role of HIF-1α in transcriptionally controlling PFKP messenger RNA by chromatin immunoprecipitation-quantitative polymerase chain reaction technique; and (iii) the effect of mitoquinol (MitoQ), a mitochondria-specific antioxidant, on HIF-1α function, glycolysis, phagocytosis, and pathogen clearance in ethanol-exposed macrophages. Last, we examined the effect of MitoQ on 7-d survival in alcohol vs. vehicle-drinking mice with cecal slurry-induced sepsis. In ethanol-exposed and lipopolysaccharide-stimulated macrophages, we found that (i) excessive total and mitochondrial ROS production and dampened phagocytosis, glycolysis, and PFKP expression; (ii) dysfunctional HIF-1α downregulates PFKP transcription; (iii) MitoQ restrains ROS production, restores HIF-1α function, and improves glycolysis and phagocytosis via preserved PFKP messenger RNA and protein expression; and (iv) MitoQ treatment improves survival and pathogen clearance in ethanol with sepsis mice. In conclusion, we found that the HIF-1α-PFKP axis regulates glycolysis and phagocytosis in ethanol-exposed macrophages and is a potential therapeutic target in ethanol with sepsis.

Overview of MitoQ on prevention and management of cardiometabolic diseases: a scoping review

Background

The exploration of mitochondrial-targeted antioxidants represented a burgeoning field of research with significant implications for cardiometabolic diseases (CMD). The studies reviewed in this scoping analysis collectively highlighted the effect of MitoQ on prevention and management of CMD and underlying mechanisms were discussed, mainly including cardiovascular diseases (CVDs), liver health and others.

Methods

This scoping review aimed to synthesize current research on the health impacts of MitoQ on CMD, focusing primarily on human-based clinical trials. While the primary focus was on human trials, in vivo and in vitro studies were referenced as supplementary material to provide a broader understanding of MitoQ's mechanisms and potential effects.

Results

This scoping review had synthesized the findings that collectively contributed to the understanding of mitochondrial-targeted antioxidants and their role in CMD.

Conclusion

The synthesis of these findings illustrated a broad spectrum of benefits ranging from enhanced insulin secretion to improved lipid profiles and mitochondrial function, yet the path to clinical application required further investigation on appropriate doses and populations.

Mitochondrial DNA leakage: underlying mechanisms and therapeutic implications in neurological disorders

Mitochondrial dysfunction is a pivotal instigator of neuroinflammation, with mitochondrial DNA (mtDNA) leakage as a critical intermediary. This review delineates the intricate pathways leading to mtDNA release, which include membrane permeabilization, vesicular trafficking, disruption of homeostatic regulation, and abnormalities in mitochondrial dynamics. The escaped mtDNA activates cytosolic DNA sensors, especially cyclic gmp-amp synthase (cGAS) signalling and inflammasome, initiating neuroinflammatory cascades via pathways, exacerbating a spectrum of neurological pathologies. The therapeutic promise of targeting mtDNA leakage is discussed in detail, underscoring the necessity for a multifaceted strategy that encompasses the preservation of mtDNA homeostasis, prevention of membrane leakage, reestablishment of mitochondrial dynamics, and inhibition the activation of cytosolic DNA sensors. Advancing our understanding of the complex interplay between mtDNA leakage and neuroinflammation is imperative for developing precision therapeutic interventions for neurological disorders.

Molecular mechanism and potential role of mitophagy in acute pancreatitis

Acute pancreatitis (AP) is a multifaceted inflammatory disorder stemming from the aberrant activation of trypsin within the pancreas. Despite the contribution of various factors to the pathogenesis of AP, such as trypsin activation, dysregulated increases in cytosolic Ca2+ levels, inflammatory cascade activation, and mitochondrial dysfunction, the precise molecular mechanisms underlying the disease are still not fully understood. Mitophagy, a cellular process that preserves mitochondrial homeostasis under stress, has emerged as a pivotal player in the context of AP. Research suggests that augmenting mitophagy can mitigate pancreatic injury by clearing away malfunctioning mitochondria. Elucidating the role of mitophagy in AP may pave the way for novel therapeutic strategies. This review article aims to synthesize the current research findings on mitophagy in AP and underscore its significance in the clinical management of the disorder.

The association of TNF-alpha secretion and mtDNA copy number in CD14+ monocytes of patients with obesity and CHD

Introduction

Mitochondrial dysfunction may be one of the causes of inflammatory activation of monocytes and macrophages, which leads to excessive secretion of inflammatory mediators and the development of chronic inflammation.

Aims

The study was aimed to evaluate the secretion of inflammatory cytokine tumor necrosis factor-α (TNF-α) in the primary culture of monocytes, and to analyze its relationship with the number of mitochondrial DNA (mtDNA) copies in the blood of patients with coronary heart disease (CHD) and obesity.

Materials and methods

108 patients with obesity and concomitant CHD and a control group of 25 participants were included in the study. CD14+ monocytes were isolated by a standard method in a ficoll-urographin gradient, followed by separation using magnetic particles. The number of mtDNA copies was estimated using qPCR.

Results

It was demonstrated that the number of mtDNA copies was significantly increased in groups of patients with CHD and obesity + CHD in comparison with control group. mtDNA copy number positively correlated with basal and LPS-stimulated TNF-α secretion, the most significant correlation was found in the group of patients with CHD and obesity.

Conclusion

Thus, the change in mtDNA copy number in CD14+ monocytes which indicates the presence of mitochondrial dysfunction, confirm the direct involvement of mitochondria in the violation of the inflammatory response of monocytes revealed in this study as an increased secretion of inflammatory cytokine TNF-α.

Circulating Oxidized mtDNA is Associated Broadly with Cardiovascular Disease in a Longitudinal Cohort Study of Psoriasis

Psoriasis (PSO) is a chronic and systemic inflammatory autoimmune disease associated with atherosclerosis and myocardial infarction. Given that atherosclerosis is both inflammation and immune driven, we sought to expand on known immune and inflammatory biomarkers in a PSO cohort. In this study, we focus on oxidized mtDNA (ox-mtDNA), a product of cells undergoing pyroptosis, including keratinocytes, which was quantified in patients with PSO and individuals without PSO by ELISA. Patients with PSO had significantly higher ox-mtDNA levels than healthy subjects (mean ± SD = 9246 ± 2518 pg/ml for patients with PSO vs 7382 ± 2506 pg/ml for those without; P = .006). Importantly, ox-mtDNA was positively associated with IL-17a (β = 0.25; P = .03) and low-density granulocytes (β = 0.37; P = .005) but negatively associated with high-density lipoprotein-cholesterol (β = -0.29; P = .006). After adjusting for traditional cardiovascular risk factors, we found that ox-mtDNA was associated with noncalcified coronary burden, which was measured by coronary computed tomography angiography (β = 0.19; P = .003). Biologic-naïve patients with PSO receiving anti-IL-17a therapy had a 14% decrease in ox-mtDNA (mean ± SD: 10540 ± 614 pg/ml at baseline to 9016 ± 477 pg/ml at 1 year; P = .016) and a 10% reduction in noncalcified coronary artery burden (mean ± SD: 1.06 ± 0.45 at baseline, reducing to 0.95 ± 0.35 at 1 year; P = .0037). In summary, levels of ox-mtDNA in PSO are associated with measures of coronary plaque formation, indicating that this biomarker may be an autoimmune-driven early atherosclerotic feature.

Mitochondrial Dysfunction Associated with mtDNA in Metabolic Syndrome and Obesity

Metabolic syndrome (MetS) is a precursor to the major health diseases associated with high mortality in industrialized countries: cardiovascular disease and diabetes. An important component of the pathogenesis of the metabolic syndrome is mitochondrial dysfunction, which is associated with tissue hypoxia, disruption of mitochondrial integrity, increased production of reactive oxygen species, and a decrease in ATP, leading to a chronic inflammatory state that affects tissues and organ systems. The mitochondrial AAA + protease Lon (Lonp1) has a broad spectrum of activities. In addition to its classical function (degradation of misfolded or damaged proteins), enzymatic activity (proteolysis, chaperone activity, mitochondrial DNA (mtDNA)binding) has been demonstrated. At the same time, the spectrum of Lonp1 activity extends to the regulation of cellular processes inside mitochondria, as well as outside mitochondria (nuclear localization). This mitochondrial protease with enzymatic activity may be a promising molecular target for the development of targeted therapy for MetS and its components. The aim of this review is to elucidate the role of mtDNA in the pathogenesis of metabolic syndrome and its components as a key component of mitochondrial dysfunction and to describe the promising and little-studied AAA + LonP1 protease as a potential target in metabolic disorders.