Role In Mitochondrial Metabolism Research Articles

Mitochondrial perturbation in immune cells enhances cell-mediated innate immunity in Drosophila

BackgroundMitochondria participate in various cellular processes including energy metabolism, apoptosis, autophagy, production of reactive oxygen species, stress responses, inflammation and immunity. However, the role of mitochondrial metabolism in immune cells and tissues shaping the innate immune responses are not yet fully understood. We investigated the effects of tissue-specific mitochondrial perturbation on the immune responses at the organismal level. Genes for oxidative phosphorylation (OXPHOS) complexes cI-cV were knocked down in the fruit fly Drosophila melanogaster, targeting the two main immune tissues, the fat body and the immune cells (hemocytes).ResultsWhile OXPHOS perturbation in the fat body was detrimental, hemocyte-specific perturbation led to an enhanced immunocompetence. This was accompanied by the formation of melanized hemocyte aggregates (melanotic nodules), a sign of activation of cell-mediated innate immunity. Furthermore, the hemocyte-specific OXPHOS perturbation induced immune activation of hemocytes, resulting in an infection-like hemocyte profile and an enhanced immune response against parasitoid wasp infection. In addition, OXPHOS perturbation in hemocytes resulted in mitochondrial membrane depolarization and upregulation of genes associated with the mitochondrial unfolded protein response.ConclusionsOverall, we show that while the effects of mitochondrial perturbation on immune responses are highly tissue-specific, mild mitochondrial dysfunction can be beneficial in immune-challenged individuals and contributes to variation in infection outcomes among individuals.

The emerging role for neutrophil mitochondrial metabolism in lung inflammation.

Recent advances shed light on the importance of mitochondrial metabolism in supporting essential neutrophil functions such as trafficking, NETosis, bacterial killing, and modulating inflammatory responses. Mitochondrial metabolism is now recognized to contribute to a number of lung diseases marked by neutrophilic inflammation, including bacterial pneumonia, acute lung injury, and chronic obstructive pulmonary disease. In this mini review, we provide an overview of neutrophil metabolism focusing on the role of mitochondrial programs, discuss select neutrophil effector functions that are directly influenced by mitochondrial metabolism, and present what is known about the role for mitochondrial metabolism in lung diseases marked by neutrophilic inflammation.

Mitochondrial Dynamics in Pulmonary Hypertension.

Mitochondria are essential organelles for energy production, calcium homeostasis, redox signaling, and other cellular responses involved in pulmonary vascular biology and disease processes. Mitochondrial homeostasis depends on a balance in mitochondrial fusion and fission (dynamics). Mitochondrial dynamics are regulated by a viable circadian clock. Hypoxia and nicotine exposure can cause dysfunctions in mitochondrial dynamics, increases in mitochondrial reactive oxygen species generation and calcium concentration, and decreases in ATP production. These mitochondrial changes contribute significantly to pulmonary vascular oxidative stress, inflammatory responses, contractile dysfunction, pathologic remodeling, and eventually pulmonary hypertension. In this review article, therefore, we primarily summarize recent advances in basic, translational, and clinical studies of circadian roles in mitochondrial metabolism in the pulmonary vasculature. This knowledge may not only be crucial to fully understanding the development of pulmonary hypertension, but also greatly help to create new therapeutic strategies for treating this devastating disease and other related pulmonary disorders.

NanoBubble-Mediated Oxygenation: Elucidating the Underlying Molecular Mechanisms in Hypoxia and Mitochondrial-Related Pathologies

Worldwide, hypoxia-related conditions, including cancer, COVID-19, and neuro-degenerative diseases, often lead to multi-organ failure and significant mortality. Oxygen, crucial for cellular function, becomes scarce as levels drop below 10 mmHg (<2% O2), triggering mitochondrial dysregulation and activating hypoxia-induced factors (HiFs). Herein, oxygen nanobubbles (OnB), an emerging versatile oxygen delivery platform, offer a novel approach to address hypoxia-related pathologies. This review explores OnB oxygen delivery strategies and systems, including diffusion, ultrasound, photodynamic, and pH-responsive nanobubbles. It delves into the nanoscale mechanisms of OnB, elucidating their role in mitochondrial metabolism (TFAM, PGC1alpha), hypoxic responses (HiF-1alpha), and their interplay in chronic pathologies including cancer and neurodegenerative disorders, amongst others. By understanding these dynamics and underlying mechanisms, this article aims to contribute to our accruing knowledge of OnB and the developing potential in ameliorating hypoxia- and metabolic stress-related conditions and fostering innovative therapies.

TIF1γ Counteracts Ferroptosis to Drive Erythroid Progenitor Differentiation

Understanding in-vivo mechanisms of hematopoiesis is critical for developing directed blood differentiation approaches to treat blood disorders such as leukemias. Zebrafish moonshine ( mon) mutant embryos defective for transcriptional intermediary factor 1 gamma ( tif1γ), a conserved transcription elongation and chromatin factor, lack red blood cells due to a block in hematopoietic stem cell differentiation along the erythroid lineage. We recently showed that TIF1γ plays a critical role in mitochondrial metabolism, including maintaining adequate coenzyme Q levels. Through a chemical suppressor screen for the mon mutant, we identified inhibitors of the essential mitochondrial pyrimidine synthesis enzyme dihydroorotate dehydrogenase to promote erythroid differentiation in mon mutants due to its functional link to the electron transport chain. In agreement, our in-vivo metabolomics analyses identified nucleotide metabolism as the most significantly altered processes in mon mutants, with elevated levels of uridine monophosphate and low levels of N-carbamoyl-L-aspartate. Interestingly, imbalances in nucleotide metabolism similar to those in mon mutants have also been reported in the presence of active ferroptosis, a pathway of programmed cell death due to iron-dependent lipid peroxidation. Through transcriptome profiling upon tif1γ loss of function in zebrafish embryos at the onset of hematopoiesis, we uncovered an expression signature indicative of activated ferroptosis. gpx4 and fsp1, inhibitors of ferroptosis acting in parallel pathways, were both downregulated, and chac1 and ptgs2, an enhancer and marker of ferroptosis, respectively, were upregulated. In addition, parallel genome-wide expression and chromatin immunoprecipitation analyses identified anti-ferroptotic genes as direct TIF1γ targets in human cells. In support of these results, we found mon mutants to exhibit increased levels of lipid peroxidation. Functionally, tif1γ loss of function synergizes with loss of gpx4 in blocking erythroid differentiation. These results demonstrate a tight coordination of nucleotide metabolism, mitochondrial respiration, and the regulation of lipid peroxidation as a key function of tif1γ-dependent transcription that drives cell fate decisions in the early erythroid lineage. Our work highlights the importance of the plasticity achieved by transcription regulatory processes such as transcription elongation for metabolic processes during lineage differentiation and could have therapeutic potential for blood diseases.

Sirtuin 5 Alleviates Liver Ischemia/Reperfusion Injury by Regulating Mitochondrial Succinylation and Oxidative Stress.

Aims: Mitochondrial dysfunction is the primary mechanism of liver ischemia/reperfusion (I/R) injury. The lysine desuccinylase sirtuin 5 (SIRT5) is a global regulator of the mitochondrial succinylome and has pivotal roles in mitochondrial metabolism and function; however, its hepatoprotective capacity in liver I/R remains unclear. In this study, we established liver I/R model in SIRT5-silenced and SIRT5-overexpressed mice to examine the role and precise mechanisms of SIRT5 in liver I/R injury. Results: Succinylation was strongly enriched in liver mitochondria during I/R, and inhibiting mitochondrial succinylation significantly attenuated liver I/R injury. Importantly, the levels of the desuccinylase SIRT5 were notably decreased in liver transplant patients, as well as in mice subjected to I/R and in AML12 cells exposed to hypoxia/reoxygenation. Furthermore, SIRT5 significantly ameliorated liver I/R-induced oxidative injury, apoptosis, and inflammation by regulating mitochondrial oxidative stress and function. Intriguingly, the hepatoprotective effect of SIRT5 was mediated by PRDX3. Mechanistically, SIRT5 specifically desuccinylated PRDX3 at the K84 site, which enabled PRDX3 to alleviate mitochondrial oxidative stress during liver I/R. Innovation: This study denoted the new effect and mechanism of SIRT5 in regulating mitochondrial oxidative stress through lysine desuccinylation, thus preventing liver I/R injury. Conclusions: Our findings demonstrate for the first time that SIRT5 is a key mediator of liver I/R that regulates mitochondrial oxidative stress through the desuccinylation of PRDX3, which provides a novel strategy to prevent liver I/R injury. Antioxid. Redox Signal. 40, 616-631.

C17orf80 binds the mitochondrial genome to promote its replication.

Serving as the power plant and signaling hub of a cell, mitochondria contain their own genome which encodes proteins essential for energy metabolism and forms DNA-protein assemblies called nucleoids. Mitochondrial DNA (mtDNA) exists in multiple copies within each cell ranging from hundreds to tens of thousands. Maintaining mtDNA homeostasis is vital for healthy cells, and its dysregulation causes multiple human diseases. However, the players involved in regulating mtDNA maintenance are largely unknown though the core components of its replication machinery have been characterized. Here, we identify C17orf80, a functionally uncharacterized protein, as a critical player in maintaining mtDNA homeostasis. C17orf80 primarily localizes to mitochondrial nucleoid foci and exhibits robust double-stranded DNA binding activity throughout the mitochondrial genome, thus constituting a bona fide new mitochondrial nucleoid protein. It controls mtDNA levels by promoting mtDNA replication and plays important roles in mitochondrial metabolism and cell proliferation. Our findings provide a potential target for therapeutics of human diseases associated with defective mtDNA control.

ATP synthase affects lipid metabolism in the kissing bug Rhodnius prolixus beyond its role in energy metabolism

ATP synthase plays an essential role in mitochondrial metabolism, being responsible for the production of ATP in oxidative phosphorylation. However, recent results have shown that it may also be present in the cell membrane, involved in lipophorin binding to its receptors. Here, we used a functional genetics approach to investigate the roles of ATP synthase in lipid metabolism in the kissing bug Rhodnius prolixus. The genome of R. prolixus encodes five nucleotide-binding domain genes of the ATP synthase α and β family, including the α and β subunits of ATP synthase (RpATPSynα and RpATPSynβ), and the catalytic and non-catalytic subunits of the vacuolar ATPase (RpVha68 and RpVha55). These genes were expressed in all analyzed organsn highest in the ovaries, fat body and flight muscle. Feeding did not regulate the expression of ATP synthases in the posterior midgut or fat body. Furthermore, ATP synthase is present in the fat body's mitochondrial and membrane fractions. RpATPSynβ knockdown by RNAi impaired ovarian development and reduced egg-laying by approximately 85%. Furthermore, the lack of RpATPSynβ increased the amount of triacylglycerol in the fat body due to increased de novo fatty acid synthesis and reduced transfer of lipids to lipophorin. RpATPSynα knockdown had similar effects, with altered ovarian development, reduced oviposition, and triacylglycerol accumulation in the fat body. However, ATP synthases knockdown had only a slight effect on the amount of ATP in the fat body. These results support the hypothesis that ATP synthase has a direct role in lipid metabolism and lipophorin physiology, which are not directly due to changes in energy metabolism.

Separation and Simultaneous Trapping of Multiply Charged and Singly Charged Ions for Mass Spectrometry: Application to Lipid Mixtures.

Conventional electrospray ionization (ESI) of mixtures can give rise to singly and multiply charged analyte species that overlap in mass-to-charge (m/z) ratios, which can complicate the analysis of individual components. The overlap in m/z for ions of different mass and charge is particularly problematic when ions of low relative abundance are of interest. For example, cardiolipins (CLs) are structurally complex phospholipids present in low relative abundance in the lipidome but play crucial roles in mitochondrial metabolism and various regulatory processes. ESI of CLs in negative ion mode shows abundant doubly deprotonated ions and minor singly deprotonated ions. In the ESI of lipid extracts, highly abundant singly charged phospholipids extensively overlap in m/z space with CL dianions of much lesser abundance, thereby complicating the study of the CLs. To address this challenge, we employed a gas-phase approach to separate singly charged ions from a population of ions of mixed charge states while allowing for the storage of one or both of the separated ion populations. Herein, we describe the considerations for applying enhanced singly charged (ESC) and enhanced multiply charged (EMC) scans to perform a gas-phase separation of singly charged lipids from doubly charged lipids in an Escherichia coli extract. This method allows for improved signal-to-noise (S/N) ratio of low abundance ions with minimal overall signal loss, removal of "chemical noise" arising from singly charged ions, and allows for retention of spatially separated ions within a mass spectrometer.

Sirtuins and redox signaling interplay in neurogenesis, neurodegenerative diseases, and neural cell reprogramming.

Since the discovery of Neural Stem Cells (NSCs) there are still mechanism to be clarified, such as the role of mitochondrial metabolism in the regulation of endogenous adult neurogenesis and its implication in neurodegeneration. Although stem cells require glycolysis to maintain their stemness, they can perform oxidative phosphorylation and it is becoming more and more evident that mitochondria are central players, not only for ATP production but also for neuronal differentiation's steps regulation, through their ability to handle cellular redox state, intracellular signaling, epigenetic state of the cell, as well as the gut microbiota-brain axis, upon dietary influences. In this scenario, the 8-oxoguanine DNA glycosylase (OGG1) repair system would link mitochondrial DNA integrity to the modulation of neural differentiation. On the other side, there is an increasing interest in NSCs generation, from induced pluripotent stem cells, as a clinical model for neurodegenerative diseases (NDs), although this methodology still presents several drawbacks, mainly related to the reprogramming process. Indeed, high levels of reactive oxygen species (ROS), associated with telomere shortening, genomic instability, and defective mitochondrial dynamics, lead to pluripotency limitation and reprogramming efficiency's reduction. Moreover, while a physiological or moderate ROS increase serves as a signaling mechanism, to activate differentiation and suppress self-renewal, excessive oxidative stress is a common feature of NDs and aging. This ROS-dependent regulatory effect might be modulated by newly identified ROS suppressors, including the NAD+-dependent deacetylase enzymes family called Sirtuins (SIRTs). Recently, the importance of subcellular localization of NAD synthesis has been coupled to different roles for NAD in chromatin stability, DNA repair, circadian rhythms, and longevity. SIRTs have been described as involved in the control of both telomere's chromatin state and expression of nuclear gene involved in the regulation of mitochondrial gene expression, as well as in several NDs and aging. SIRTs are ubiquitously expressed in the mammalian brain, where they play important roles. In this review we summarize the current knowledge on how SIRTs-dependent modulation of mitochondrial metabolism could impact on neurogenesis and neurodegeneration, focusing mainly on ROS function and their role in SIRTs-mediated cell reprogramming and telomere protection.

Role of mitochondrial metabolism in immune checkpoint inhibitors-related myocarditis.

Immune checkpoint inhibitor-related myocarditis is the deadliest complication of immunotherapy. However, the underlying pathophysiological mechanisms of its occurrence and development remain unclear. Due to the long-term lack of effective early diagnosis and treatment options, it is of great significance to understand the pathophysiological mechanism of immune checkpoint inhibitor-related myocarditis. Tissue samples from three patients with immune checkpoint inhibitor-related myocarditis and three control tissue samples were collected for protein analysis. Differentially expressed proteins were screened out using quantitative proteomics technology based on TMT markers. Protein-protein interaction (PPI) and Gene Ontology (GO) functional enrichment analyses of cross-factors were subsequently performed. Combined with the PD-L1 subcellular organelle- level protein interaction network, we searched for hub proteins involved in immune checkpoint inhibitor-related myocarditis and explored potential drug sensitivity and disease correlation. A total of 306 differentially expressed proteins were identified in immune checkpoint inhibitor-related myocarditis. Enrichment analysis showed that the differentially expressed proteins were closely related to mitochondrial metabolism. By analyzing mitochondria-related proteins and PD-L1-related proteins, we found four hub proteins, mammalian target of rapamycin (mTOR), Glycogen synthase kinase 3β (GSK3β), Protein tyrosine phosphatase non-receptor type 11 (PTPN11), and Mitofusin 2 (MFN2), indicating that they are closely related to immune checkpoint inhibitor-related myocarditis. Finally, we explored potential drugs for the treatment of immune checkpoint inhibitor-related myocarditis. Mitochondrial metabolism is involved in the process of immune checkpoint inhibitor-related myocarditis, and we identified four hub proteins, which may become new biomarkers for the early diagnosis and treatment of immune checkpoint inhibitor-related myocarditis.

Arterial remodeling: the role of mitochondrial metabolism in vascular smooth muscle cells.

Arterial remodeling is a common pathological basis of cardiovascular diseases such as atherosclerosis, vascular restenosis, hypertension, pulmonary hypertension, aortic dissection, and aneurysm. Vascular smooth muscle cells (VSMCs) are not only the main cellular components in the middle layer of the arterial wall but also the main cells involved in arterial remodeling. Dedifferentiated VSMCs lose their contractile properties and are converted to a synthetic, secretory, proliferative, and migratory phenotype, playing key roles in the pathogenesis of arterial remodeling. As mitochondria are the main site of biological oxidation and energy transformation in eukaryotic cells, mitochondrial numbers and function are very important in maintaining the metabolic processes in VSMCs. Mitochondrial dysfunction and oxidative stress are novel triggers of the phenotypic transformation of VSMCs, leading to the onset and development of arterial remodeling. Therefore, pharmacological measures that alleviate mitochondrial dysfunction reverse arterial remodeling by ameliorating VSMCs metabolic dysfunction and phenotypic transformation, providing new options for the treatment of cardiovascular diseases related to arterial remodeling. This review summarizes the relationship between mitochondrial dysfunction and cardiovascular diseases associated with arterial remodeling and then discusses the potential mechanism by which mitochondrial dysfunction participates in pathological arterial remodeling. Furthermore, maintaining or improving mitochondrial function may be a new intervention strategy to prevent the progression of arterial remodeling.

Clinical significance of mitochondrial DNA content in acute promyelocytic leukaemia.

Although a growing body of evidence demonstrates that altered mtDNA content (mtDNAc) has clinical implications in several types of solid tumours, its prognostic relevance in acute promyelocytic leukaemia (APL) patients remains largely unknown. Here, we show that patients with higher-than-normal mtDNAc had better outcomes regardless of tumour burden. These results were more evident in patients with low-risk of relapse. The multivariate Cox proportional hazard model demonstrated that high mtDNAc was independently associated with a decreased cumulative incidence of relapse. Altogether, our data highlights the possible role of mitochondrial metabolism in APL patients treated with ATRA.

Transcriptome Analysis of Protein Kinase MoCK2, which Affects Acetyl-CoA Metabolism and Import of CK2-Interacting Mitochondrial Proteins into Mitochondria in the Rice Blast Fungus Magnaporthe oryzae.

The rice pathogen Magnaporthe oryzae causes severe losses to rice production. Previous studies have shown that the protein kinase MoCK2 is essential for pathogenesis, and this ubiquitous eukaryotic protein kinase might affect several processes in the fungus that are needed for infection. To better understand which cellular processes are affected by MoCK2 activity, we performed a detailed transcriptome sequencing analysis of deletions of the MoCK2 b1 and b2 components in relation to the background strain Ku80 and connected this analysis with the abundance of substrates for proteins in a previous pulldown of the essential CKa subunit of CK2 to estimate the effects on proteins directly interacting with CK2. The results showed that MoCK2 seriously affected carbohydrate metabolism, fatty acid metabolism, amino acid metabolism, and the related transporters and reduced acetyl-CoA production. CK2 phosphorylation can affect the folding of proteins and especially the effective formation of protein complexes by intrinsically disordered or mitochondrial import by destabilizing soluble alpha helices. The upregulated genes found in the pulldown of the b1 and b2 mutants indicate that proteins directly interacting with CK2 are compensatorily upregulated depending on their pulldown. A similar correlation was found for mitochondrial proteins. Taken together, the classes of proteins and the changes in regulation in the b1 and b2 mutants suggest that CK2 has a central role in mitochondrial metabolism, secondary metabolism, and reactive oxygen species (ROS) resistance, in addition to its previously suggested role in the formation of new ribosomes, all of which are processes central to efficient nonself responses as innate immunity. IMPORTANCE The protein kinase CK2 is highly expressed and essential for plants, animals, and fungi, affecting fatty acid-related metabolism. In addition, it directly affects the import of essential mitochondrial proteins into mitochondria. These effects mean that CK2 is essential for lipid metabolism and mitochondrial function and, as shown previously, is crucial for making new translation machinery proteins. Taken together, our new results combined with previously reported results indicate that CK2 is an essential protein necessary for the capacities to launch efficient innate immunity responses and withstand the negative effects of such responses necessary for general resistance against invading bacteria and viruses as well as to interact with plants, withstand plant immunity responses, and kill plant cells.

Effects of Noonan Syndrome-Germline Mutations on Mitochondria and Energy Metabolism.

Noonan syndrome (NS) and related Noonan syndrome with multiple lentigines (NSML) contribute to the pathogenesis of human diseases in the RASopathy family. This family of genetic disorders constitute one of the largest groups of developmental disorders with variable penetrance and severity, associated with distinctive congenital disabilities, including facial features, cardiopathies, growth and skeletal abnormalities, developmental delay/mental retardation, and tumor predisposition. NS was first clinically described decades ago, and several genes have since been identified, providing a molecular foundation to understand their physiopathology and identify targets for therapeutic strategies. These genes encode proteins that participate in, or regulate, RAS/MAPK signalling. The RAS pathway regulates cellular metabolism by controlling mitochondrial homeostasis, dynamics, and energy production; however, little is known about the role of mitochondrial metabolism in NS and NSML. This manuscript comprehensively reviews the most frequently mutated genes responsible for NS and NSML, covering their role in the current knowledge of cellular signalling pathways, and focuses on the pathophysiological outcomes on mitochondria and energy metabolism.

The Role of Glutathione Metabolism in Chronic Illness Development and Its Potential Use as a Novel Therapeutic Target.

Glutathione (GSH) is the most abundant thiol antioxidant in the human body and serves many important biochemical functions, including the regulation of vitamins, such as vitamins D, E, and C, and detoxification of drugs and toxins. As a powerful antioxidant, GSH is particularly important as a regulator of mitochondrial metabolism and a free radical scavenger that limits oxidative damage to cellular components. Low GSH levels have been associated with many chronic pro-inflammatory conditions, such as metabolic syndrome, cardiovascular, renal, and hepatic disease, as well as neurodegenerative conditions and autoimmune diseases. Given GSH's known direct protective role in mitochondrial metabolism and its association with chronic diseases of highly metabolically active tissues, this review aims to examine the literature for evidence that low GSH levels may be an important causative factor in the development of chronic illnesses. Because no large prospective human trials have been conducted using direct measurements of GSH, this review focused on the more common biomarker gamma-glutamyl transferase (GGT) which is directly correlated to low GSH levels. Several large prospective studies support this hypothesis by demonstrating that higher GGT levels are correlated with the risk of developing metabolic syndrome and cardiovascular disease in a dose-dependent fashion. Furthermore, as a corollary to this hypothesis, human and animal trials utilizing GSH augmentation using precursor supplementation in chronic conditions, including metabolic syndrome, cardiovascular disease, hepatic disease, renal disease, and neurodegenerative conditions, were also reviewed. While many of these trials were preliminary and small, there is strong evidence that GSH supplementation leads to improved outcomes in all of these chronic conditions. This review seeks to highlight these studies as preliminary evidence demonstrating the contributory role of GSH in chronic disease progression because a simple and cost-effective strategy can be created to screen for, track, and intervene in susceptible patients in the primary care setting at the earliest possible time in the disease process. Such a novel strategy would impact the majority of chronic diseases contributing to the bulk of morbidity and mortality in the Western world, and, thus, even minor benefits across many conditions may substantially impact population-wide health and longevity.

The Role of Mitochondrial Metabolism, AMPK-SIRT Mediated Pathway, LncRNA and MicroRNA in Osteoarthritis.

Osteoarthritis (OA) is the most common joint disease characterized by degeneration of articular cartilage and causes severe joint pain, physical disability, and impaired quality of life. Recently, it was found that mitochondria not only act as a powerhouse of cells that provide energy for cellular metabolism, but are also involved in crucial pathways responsible for maintaining chondrocyte physiology. Therefore, a growing amount of evidence emphasizes that impairment of mitochondrial function is associated with OA pathogenesis; however, the exact mechanism is not well known. Moreover, the AMP-activated protein kinase (AMPK)–Sirtuin (SIRT) signaling pathway, long non-coding RNA (lncRNA), and microRNA (miRNA) are important for regulating the physiological and pathological processes of chondrocytes, indicating that these may be targets for OA treatment. In this review, we first focus on the importance of mitochondria metabolic dysregulation related to OA. Then, we show recent evidence on the AMPK-SIRT mediated pathway associated with OA pathogenesis and potential treatment options. Finally, we discuss current research into the effects of lncRNA and miRNA on OA progression or inhibition.

Cardiac mitochondrial energetics of the Australasian red spiny lobster, Jasus edwardsii, when exposed to isoeugenol within the commercial anaesthetic AQUI-S.

The anaesthetic isoeugenol has been used as metabolic suppressant for commercial transport of live lobsters in order to decrease energy expenditure and improve survival. Given the central role of mitochondria in metabolism and structural similarities of isoeugenol to the mitochondrial electron carrier coenzyme Q, we explored the influence on mitochondrial function of isoeugenol. Mitochondrial function was measured using high-resolution respirometry and saponin-permeabilised heart fibres from the Australasian red spiny lobster, Jasus edwardsii. Relative to vehicle (polysorbate), isoeugenol inhibited respiration supported by complex I (CI) and cytochrome c oxidase (CCO). While complex II (CII), which also reduces coenzyme Q, was largely unaffected by isoeugenol, respiration supported by CII when uncoupled was depressed. Titration of isoeugenol indicates that respiration through CI has a half-maximal inhibitory concentration (IC50) of 2.4±0.1 µmoll-1, and a full-maximal inhibitory concentration (IC100-) of approximately 6.3 µmoll-1. These concentrations are consistent with those used for transport and euthanasia of J. edwardsii and indicate that CI is a possible target of isoeugenol, like many other anaesthetics with quinone-like structures.

Nicotinamide mononucleotide ameliorates acute lung injury by inducing mitonuclear protein imbalance and activating the UPRmt.

Mitochondria need to interact with the nucleus under homeostasis and stress to maintain cellular demands and nuclear transcriptional programs. Disrupted mitonuclear interaction is involved in many disease processes. However, the role of mitonuclear signaling regulators in endotoxin-induced acute lung injury (ALI) remains unknown. Nicotinamide adenine dinucleotide (NAD+) is closely related to mitonuclear interaction with its central role in mitochondrial metabolism. In the current study, C57BL/6J mice were administrated with lipopolysaccharide 15 mg/kg to induce endotoxin-induced ALI and investigated whether the NAD+ precursor nicotinamide mononucleotide (NMN) could preserve mitonuclear interaction and alleviate ALI. After pretreatment with NMN for 7 days, NAD+ levels in the mitochondrial, nucleus, and total intracellular were significantly increased in endotoxemia mice. Moreover, supplementation of NMN alleviated lung pathologic injury, reduced ROS levels, increased MnSOD activities, mitigated mitochondrial dysfunction, ameliorated the defects in the nucleus morphology, and these cytoprotective effects were accompanied by preserving mitonuclear interaction (including mitonuclear protein imbalance and the mitochondrial unfolded protein response, UPRmt). Furthermore, NAD+-mediated mitonuclear protein imbalance and UPRmt are probably regulated by deacetylase Sirtuin1 (SIRT1). Taken together, our results indicated that NMN pretreatment ameliorated ALI by inducing mitonuclear protein imbalance and activating the UPRmt in an SIRT1-dependent manner.

The Role of the Metabolism of Zinc and Manganese Ions in Human Cancerogenesis.

Metal ion homeostasis is fundamental for life. Specifically, transition metals iron, manganese and zinc play a pivotal role in mitochondrial metabolism and energy generation, anti-oxidation defense, transcriptional regulation and the immune response. The misregulation of expression or mutations in ion carriers and the corresponding changes in Mn2+ and Zn2+ levels suggest that these ions play a pivotal role in cancer progression. Moreover, coordinated changes in Mn2+ and Zn2+ ion carriers have been detected, suggesting that particular mechanisms influenced by both ions might be required for the growth of cancer cells, metastasis and immune evasion. Here, we present a review of zinc and manganese pathophysiology suggesting that these ions might cooperatively regulate cancerogenesis. Zn and Mn effects converge on mitochondria-induced apoptosis, transcriptional regulation and the cGAS-STING signaling pathway, mediating the immune response. Both Zn and Mn influence cancer progression and impact treatment efficacy in animal models and clinical trials. We predict that novel strategies targeting the regulation of both Zn and Mn in cancer will complement current therapeutic strategies.