Impaired Mitochondrial Function Research Articles

Exposure to urban particulate matter (UPM) impairs mitochondrial dynamics in BV2 cells, triggering a mitochondrial biogenesis response.

World Health Organisation data suggest that up to 99% of the global population are exposed to air pollutants above recommended levels. Impacts to health range from increased risk of stroke and cardiovascular disease to chronic respiratory conditions, and air pollution may contribute to over 7 million premature deaths a year. Additionally, mounting evidence suggests that in utero or early life exposure to particulate matter (PM) in ambient air pollution increases the risk of neurodevelopmental impairment with obvious lifelong consequences. Identifying brain-specific cellular targets of PM is vital for determining its long-term consequences. We previously established that microglial-like BV2 cells were particularly sensitive to urban (U)PM-induced damage including reactive oxygen species production, which was abrogated by a mitochondrially targeted antioxidant. Here we extend those studies to find that UPM treatment causes a rapid impairment of mitochondrial function and increased mitochondrial fragmentation. However, there is a subsequent restoration of mitochondrial and therefore cell health occurring concomitantly with upregulated measures of mitochondrial biogenesis and mitochondrial load. Our data highlight that protecting mitochondrial function may represent a valuable mechanism to offset the effects of UPM exposure in the neonatal brain. KEY POINTS: Air pollution represents a growing risk to long-term health especially in early life, and the CNS is emerging a target for airborne particulate matter (PM). We previously showed that microglial-like BV2 cells were vulnerable to urban (U)PM exposure, which impaired cell survival and promoted reactive oxygen species production. Here we find that, following UPM exposure, BV2 mitochondrial membrane potential is rapidly reduced, concomitant with decreased cellular bioenergetics and increased mitochondrial fission. However, markers of mitochondrial biogenesis and mitochondrial mass are subsequently induced, which may represent a cellular mitigation strategy. As mitochondria are more vulnerable in the developing brain, exposure to air pollution may represent a greater risk to lifelong health in this cohort; conversely, promoting mitochondrial integrity may offset these risks.

Distinct epigenetic modulation of differentially expressed genes in the adult mouse brain following prenatal exposure to low-dose bisphenol A.

Bisphenol A (BPA) is a common component in the manufacture of daily plastic consumer goods. Recent studies have suggested that prenatal exposure to BPA can increase the susceptibility of offspring to mental illness, although the underlying mechanisms remain unclear. In this study, we performed transcriptomic and epigenomic profiling in the adult mouse brain following prenatal exposure to low-dose BPA. We observed a sex-specific transcriptional dysregulation in the cortex, with more significant differentially expressed genes was observed in adult cortex from male offspring. Moreover, the upregulated genes primarily influenced neuronal functions, while the downregulated genes were significantly associated with energy metabolism pathways. More evidence supporting impaired mitochondrial function included a decreased ATP level and a reduced number of mitochondria in the cortical neuron of the BPA group. We further investigated the higher-order chromatin regulatory patterns of DEGs by incorporating published Hi-C data. Interestingly, we found that upregulated genes exhibited more distal interactions with multiple enhancers, while downregulated genes displayed relatively short-range interactions among adjacent genes. Our data further revealed decreased H3K9me3 signal on the distal enhancers of upregulated genes, whereas increased DNA methylation and H3K27me3 signals on the promoters of downregulated genes. In summary, our study provides compelling evidence for the potential health risks associated with prenatal exposure to BPA, and uncovers sex-specific transcriptional changes with a complex interplay of multiple epigenetic mechanisms.

Targeting the mitochondrial protein YME1L to inhibit osteosarcoma cell growth in vitro and in vivo

Exploring novel diagnostic and therapeutic biomarkers is extremely important for osteosarcoma. YME1 Like 1 ATPase (YME1L), locating in the mitochondrial inner membrane, is key in regulating mitochondrial plasticity and metabolic activity. Its expression and potential functions in osteosarcoma are studied in the present study. We show that YME1L mRNA and protein expression is significantly elevated in osteosarcoma tissues derived from different human patients. Moreover, its expression is upregulated in various primary and immortalized osteosarcoma cells. The Cancer Genome Atlas database results revealed that YME1L overexpression was correlated with poor overall survival and poor disease-specific survival in sarcoma patients. In primary and immortalized osteosarcoma cells, silencing of YME1L through lentiviral shRNA robustly inhibited cell viability, proliferation, and migration. Moreover, cell cycle arrest and apoptosis were detected in YME1L-silenced osteosarcoma cells. YME1L silencing impaired mitochondrial functions in osteosarcoma cells, causing mitochondrial depolarization, oxidative injury, lipid peroxidation and DNA damage as well as mitochondrial respiratory chain complex I activity inhibition and ATP depletion. Contrarily, forced YME1L overexpression exerted pro-cancerous activity and strengthened primary osteosarcoma cell proliferation and migration. YME1L is important for Akt-S6K activation in osteosarcoma cells. Phosphorylation of Akt and S6K was inhibited after YME1L silencing in primary osteosarcoma cells, but was strengthened with YME1L overexpression. Restoring Akt-mTOR activation by S473D constitutively active Akt1 mitigated YME1L shRNA-induced anti-osteosarcoma cell activity. Lastly, intratumoral injection of YME1L shRNA adeno-associated virus inhibited subcutaneous osteosarcoma xenograft growth in nude mice. YME1L depletion, mitochondrial dysfunction, oxidative injury, Akt-S6K inactivation, and apoptosis were detected in YME1L shRNA-treated osteosarcoma xenografts. Together, overexpressed YME1L promotes osteosarcoma cell growth, possibly by maintaining mitochondrial function and Akt-mTOR activation.

The integrated stress response promotes neural stem cell survival under conditions of mitochondrial dysfunction in neurodegeneration.

Impaired mitochondrial function is a hallmark of aging and a major contributor to neurodegenerative diseases. We have shown that disrupted mitochondrial dynamics typically found in aging alters the fate of neural stem cells (NSCs) leading to impairments in learning and memory. At present, little is known regarding the mechanisms by which neural stem and progenitor cells survive and adapt to mitochondrial dysfunction. Using Opa1-inducible knockout as a model of aging and neurodegeneration, we identify a decline in neurogenesis due to impaired stem cell activation and progenitor proliferation, which can be rescued by the mitigation of oxidative stress through hypoxia. Through sc-RNA-seq, we identify the ATF4 pathway as a critical mechanism underlying cellular adaptation to metabolic stress. ATF4 knockdown in Opa1-deficient NSCs accelerates cell death, while the increased expression of ATF4 enhances proliferation and survival. Using a Slc7a11 mutant, an ATF4 target, we show that ATF4-mediated glutathione production plays a critical role in maintaining NSC survival and function under stress conditions. Together, we show that the activation of the integrated stress response (ISR) pathway enables NSCs to adapt to metabolic stress due to mitochondrial dysfunction and metabolic stress and may serve as a therapeutic target to enhance NSC survival and function in aging and neurodegeneration.

Time-restricted feeding improves aortic endothelial relaxation by enhancing mitochondrial function and attenuating oxidative stress in aged mice

Age-related endothelial dysfunction is a pivotal factor in the development of cardiovascular diseases, stemming, at least in part, from mitochondrial dysfunction and a consequential increase in oxidative stress. These alterations are central to the decline in vascular health seen with aging, underscoring the urgent need for interventions capable of restoring endothelial function for preventing cardiovascular diseases. Dietary interventions, notably time-restricted feeding (TRF), have been identified for their anti-aging effects on mitochondria, offering protection against age-associated declines in skeletal muscle and other organs. Motivated by these findings, our study aimed to investigate whether TRF could similarly exert protective effects on endothelial health in the vasculature, enhancing mitochondrial function and reducing oxidative stress. To explore this, 12-month-old C57BL/6 mice were placed on a TRF diet, with food access limited to a 6-h window daily for 12 months. For comparison, we included groups of young mice and age-matched controls with unrestricted feeding. We evaluated the impact of TRF on endothelial function by measuring acetylcholine-induced vasorelaxation of the aorta. Mitochondrial health was assessed using fluororespirometry, and vascular reactive oxygen species (ROS) production was quantified with the redox-sensitive dye dihydroethidium. We also quantified 4-hydroxynonenal (4-HNE) levels, a stable marker of lipid peroxidation, in the aorta using ELISA. Our findings demonstrated that aged mice on a standard diet exhibited significant impairments in aortic endothelial relaxation and mitochondrial function, associated with elevated vascular oxidative stress. Remarkably, the TRF regimen led to substantial improvements in these parameters, indicating enhanced endothelial vasorelaxation, better mitochondrial function, and reduced oxidative stress in the aortas of aged mice. This investigation establishes a vital foundation, paving the way for subsequent clinical research aimed at exploring the cardiovascular protective benefits of intermittent fasting.

Pirh2 modulates the mitochondrial function and cytochrome c-mediated neuronal death during Alzheimer’s disease

Pirh2 is an E3 ubiquitin ligase known to regulate the DNA damage responses through ubiquitylation of various participating signaling factors. DNA damage is a key pathological contributor to Alzheimer’s disease (AD), therefore, the role of Pirh2 was investigated in streptozotocin and oligomer Aβ1–42 induced rodent experimental model of AD. Pirh2 protein abundance increased during AD conditions, and transient silencing of Pirh2 inhibited the disease-specific pathological markers like level of p-Tau, βamyloid, acetylcholinesterase activity, and neuronal death. Biochemically, Pirh2 silencing significantly attenuated the oxidative stress, depleted mitochondrial membrane potential, cytochrome c translocation from mitochondria to cytosol, and depleted mitochondrial complex-I activity, and ATP level. Pirh2 silencing also inhibited the altered level of VDAC1, hsp75, hexokinase1, t-Bid, caspase-9, and altered level of apoptotic proteins (Bcl-2, Bax). MALDI-TOF/TOF, co-immunoprecipitation, and UbcH13-linked ubiquitylation assay confirmed the interaction of Pirh2 with cytochrome c and the role of Pirh2 in ubiquitylation of cytochrome c, along with Pirh2-dependent altered proteasome activity. Additionally, Pirh2 silencing further inhibited the translocation of mitochondrion-specific endonuclease G and apoptosis-inducing factors to the nucleus and DNA damage. In conclusion, findings suggested the significant implication of Pirh2 in disease pathogenesis, particularly through impaired mitochondrial function, including biochemical alterations, translocation of cytochrome c, endonuclease G and apoptosis-inducing factor, DNA damage, and neuronal apoptosis.

F-actin/DRP1 axis-mediated mitochondrial fission promotes mitophagy in diabetic submandibular glands.

Diabetes is accompanied by a high prevalence of hyposalivation, causing severe damage to oral and systemic health. Mitochondrial dynamics play important roles in the pathogenesis of various diabetic complications; however, little is known about their roles in diabetic hyposalivation. A diabetic mouse model and a high glucose (HG)-induced diabetic submandibular gland (SMG) cell model were employed. More mitochondria surrounded by autophagosomes and higher expression of mitophagy-related proteins were detected in the SMGs of diabetic mice and HG-treated SMG cells. In diabetic SMGs, dynamin-related protein 1 (DRP1) was upregulated, whereas mitofusin-2 was downregulated both invivo and invitro. Shortened mitochondria and impaired mitochondrial functions were observed in the HG group. A DRP1-specific inhibitor, mdivi-1, suppressed mitochondrial fission and mitophagy, as well as restored mitochondrial functions in the HG condition. Moreover, the interaction of F-actin and DRP1 was enhanced in the diabetic group. Inhibiting F-actin with cytochalasin D repaired the injured effects of HG on mitochondrial dynamics and functions. Conversely, the F-actin-polymerization-inducer jasplakinolide aggravated mitochondrial fission and dysfunction. F-actin contributes to HG-evoked mitochondrial fission by interacting with DRP1, which induces mitophagy and impairs mitochondrial function in SMG cells, ultimately damaging the SMG.

Disclosing the Antifungal Mechanisms of the Cyclam Salt H4[H2(4-CF3PhCH2)2Cyclam]Cl4 against Candida albicans and Candida krusei.

Mycoses are one of the major causes of morbidity/mortality among immunocompromised individuals. Considering the importance of these infections, the World Health Organization (WHO) defined a priority list of fungi for health in 2022 that include Candida albicans as belonging to the critical priority group and Pichia kudriavzevii (Candida krusei) to the medium priority group. The existence of few available antifungal drugs, their high toxicity, the acquired fungal resistance, and the appearance of new species with a broader spectrum of resistance, points out the need for searching for new antifungals, preferably with new and multiple mechanisms of action. The cyclam salt H4[H2(4-CF3PhCH2)2Cyclam]Cl4 was previously tested against several fungi and revealed an interesting activity, with minimal inhibitory concentration (MIC) values of 8 µg/mL for C. krusei and of 128 µg/mL for C. albicans. The main objective of the present work was to deeply understand the mechanisms involved in its antifungal activity. The effects of the cyclam salt on yeast metabolic viability (resazurin reduction assay), yeast mitochondrial function (JC-1 probe), production of reactive oxygen species (DCFH-DA probe) and on intracellular ATP levels (luciferin/luciferase assay) were evaluated. H4[H2(4-CF3PhCH2)2Cyclam]Cl4 induced a significant decrease in the metabolic activity of both C. albicans and C. krusei, an increase in Reactive Oxygen Species (ROS) production, and an impaired mitochondrial function. The latter was observed by the depolarization of the mitochondrial membrane and decrease in ATP intracellular levels, mechanisms that seems to be involved in the antifungal activity of H4[H2(4-CF3PhCH2)2Cyclam]Cl4. The interference of the cyclam salt with human cells revealed a CC50 value against HEK-293 embryonic kidney cells of 1.1 μg/mL and a HC10 value against human red blood cells of 0.8 μg/mL.

Emerging Roles of Vitamin B12 in Aging and Inflammation.

Vitamin B12 (cobalamin) is an essential nutrient for humans and animals. Metabolically active forms of B12-methylcobalamin and 5-deoxyadenosylcobalamin are cofactors for the enzymes methionine synthase and mitochondrial methylmalonyl-CoA mutase. Malfunction of these enzymes due to a scarcity of vitamin B12 leads to disturbance of one-carbon metabolism and impaired mitochondrial function. A significant fraction of the population (up to 20%) is deficient in vitamin B12, with a higher rate of deficiency among elderly people. B12 deficiency is associated with numerous hallmarks of aging at the cellular and organismal levels. Cellular senescence is characterized by high levels of DNA damage by metabolic abnormalities, increased mitochondrial dysfunction, and disturbance of epigenetic regulation. B12 deficiency could be responsible for or play a crucial part in these disorders. In this review, we focus on a comprehensive analysis of molecular mechanisms through which vitamin B12 influences aging. We review new data about how deficiency in vitamin B12 may accelerate cellular aging. Despite indications that vitamin B12 has an important role in health and healthy aging, knowledge of the influence of vitamin B12 on aging is still limited and requires further research.

Mitochondria targeted drug delivery system overcoming drug resistance in intrahepatic cholangiocarcinoma by reprogramming lipid metabolism

The challenge of drug resistance in intrahepatic cholangiocarcinoma (ICC) is intricately linked with lipid metabolism reprogramming. The hepatic lipase (HL) and the membrane receptor CD36 are overexpressed in BGJ398-resistant ICC cells, while they are essential for lipid uptake, further enhancing lipid utilization in ICC. Herein, a metal-organic framework-based drug delivery system (OB@D-pMOF/CaP-AC, DDS), has been developed. The specifically designed DDS exhibits a successive targeting property, enabling it to precisely target ICC cells and their mitochondria. By specifically targeting the mitochondria, DDS produces reactive oxygen species (ROS) through its sonodynamic therapy effect, achieving a more potent reduction in ATP levels compared to non-targeted approaches, through the impairment of mitochondrial function. Additionally, the DDS strategically minimizes lipid uptake through the incorporation of the anti-HL drug, Orlistat, and anti-CD36 monoclonal antibody, reducing lipid-derived energy production. This dual-action strategy on both mitochondria and lipids can hinder energy utilization to restore drug sensitivity to BGJ398 in ICC. Moreover, an orthotopic mice model of drug-resistant ICC was developed, which serves as an exacting platform for evaluating the multifunction of designed DDS. Upon in vivo experiments with this model, the DDS demonstrated exceptional capabilities in suppressing tumor growth, reprogramming lipid metabolism and improving immune response, thereby overcoming drug resistance. These findings underscore the mitochondria-targeted DDS as a promising and innovative solution in ICC drug resistance.

Loss of FAM210A in Satellite Cell Drives Mitochondrial Dysfunction and Muscle Weakness in Experimental Peripheral Artery Disease

Introduction: Peripheral artery disease (PAD) affects approximately 200 million people globally. Chronic limb-threatening ischemia (CLTI) represents the most advanced clinical phenotype of PAD. Mitochondrial metabolism defects are apparent in the satellite cells of CLTI patients, and the muscle regeneration process demands increased energy, with satellite cell mitochondrial metabolism and dynamics playing a crucial role. However, our current understanding of the role of satellite cells and muscle regeneration in PAD pathology is notably inadequate. Recent studies have shown that the absence of FAM210A, a newly identified mitochondrial protein, can trigger morphological and energetic abnormalities in mitochondria, resulting in muscle function deterioration and promoting muscle wasting. Given the impaired mitochondrial function in satellite cells in CLTI patients and the heightened energy demand regulated by mitochondrial dynamics during muscle regeneration in satellite cell, it is therefore essential to exploring the role of FAM210A in satellite cells in CLTI limb pathology. The objective of this study was to investigate the impact of the loss of FAM210A in satellite cells in mice with experimental PAD. Methods: Male and female conditional FAM210A satellite cell knock out (FAM210ASCKO) and FAM210A floxed (FAM210Afl/fl) mice (N=3-5) were used for this project. Femoral artery ligation surgery was performed to induce PAD. Tamoxifen was administered for 5 days intraperitoneally one week prior to the surgery. Mice were euthanized twenty-eight days after surgery. Outcome measures included limb perfusion assessment, muscle weight, muscle force production, and mitochondrial respiration. Results: FAM210ASCKO mice had significantly decreased muscle mass of the tibialis anterior and extensor digitorum longus ( p<0.0001 and p=0.0004 respectively). More importantly, maximal muscle force with in-situ contraction in tibialis anterior was significantly lower in FAM210ASCKO mice compared to FAM210Afl/fl mice (FAM210Afl/fl mice: 1085.16 ± 331.08 mN; FAM210ASCKO mice: 430.77 ± 467.91 mN; p=0.0139). Furthermore, analysis of mitochondrial oxidative phosphorylation (OXPHOS) revealed that FAM210ASCKO mice had a significant reduction compared to FAM210Afl/fl mice (48%) in skeletal muscle mitochondrial bioenergetic function at various levels of energy demand mimicking from resting to maximal exercise when carbohydrate was used to energize mitochondria ( p=0.034). Importantly, the analysis of mitochondrial membrane potential consistently reveals a substantial reduction in FAM210ASCKO mice compared to FAM210Afl/fl mice, which can partially explain the diminished mitochondrial bioenergetic function observed in ischemic FAM210ASCKO mice. Conclusion: The results of this study indicate that the loss of FAM210A in satellite cells exacerbates ischemic muscle pathology evidenced by muscle weakness and mitochondrial failure in FAM210ASCKO mice with PAD. Future work is needed to elucidate the mechanisms by which FAM210A regulate ischemic satellite cell function and the therapeutic potential of preventing ischemia-induced loss of FAM210A in PAD. This study was supported by National Institutes of Health (NIH) grant R01-HL149704 (to Dr Ryan). Mr Thome was supported by NIH grant F31-DK128920. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Nicotinic acid attenuates amyloid β1-42-induced mitochondrial dysfunction and inhibits the mitochondrial pathway of apoptosis in differentiated SH-SY5Y cells

Alzheimer's disease (AD) is a chronic neurodegenerative disease characterized by progressive memory loss and behavioral disorders. The excessive accumulation of amyloid β (Aβ) and the formation of neurofibrillary tangles (NFTs) damage synaptic connections and the death of neurons. However, the underlying mechanisms of pathogenesis of AD remain unclear. Growing evidence indicates that impaired mitochondrial function may play a crucial role in the development of AD. In the current study, we investigated whether nicotinic acid (NA) could protect against amyloid β1-42-induced cytotoxicity in differentiated SH-SY5Y cells. Our results revealed the neuroprotective effects of NA on the differentiated SH-SY5Y cells treated with Aβ1-42. In detail, the 1-h pre-incubation with NA increased cell viability and lowered LDH levels. NA pre-incubation abolished Aβ1-42 treatment-associated alterations of mRNA levels of synaptic genes and enhanced the relative β3 Tubulin fluorescence intensity. NA eliminated the Aβ1-42-induced mitochondrial dysfunction by increasing the potential of mitochondrial membranes and maintaining a balance between the fusion and fission of mitochondria. Moreover, Aβ1-42 decreased mRNA levels of anti-apoptotic bcl2 and increased mRNA levels of pro-apoptotic: bim, bak, cytochrome c, and caspase 9. At the same time, the NA pre-treatment reduced Aβ1-42-dependent apoptotic death of differentiated SH-SY5Y cells.The above data suggest that NA presents a protective activity against Aβ1-42-induced cytotoxicity in differentiated SH-SY5Y cells by inhibiting the mitochondrial pathway of apoptosis and restoring the proper function of mitochondria.

Investigation of crucial genes and mitochondrial function impairment in diabetic cardiomyopathy

BackgroundDiabetic cardiomyopathy (DCM) is a special type of cardiovascular disease, termed as a situation of abnormal myocardial structure and function that occurs in diabetic patients. However, the most fundamental mechanisms of DCM have not been fully explicated, and useful targets for the therapeutic strategies still need to be explored. MethodsIn the present study, we combined bioinformatics analysis and in vitro experiments throughout the process of DCM. Differentially Expressed Genes (DEGs) analysis was performed and the weighted gene co-expression network analysis (WGCNA) was constructed to determine the crucial genes that were tightly connected to DCM. Additionally, Functional enrichment analysis was conducted to define biological pathways. To identify the specific molecular mechanism, the human cardiomyocyte cell line (AC16) was stimulated by high glucose (HG, 50 mM D-glucose) and used to imitate DCM condition. Then, we tentatively examined the effect of high glucose on cardiomyocytes, the expression levels of crucial genes were further validated by in vitro experiments. ResultsGenerally, NPPA, IGFBP5, SERPINE1, and C3 emerged as potential therapeutic targets. Functional enrichment analysis performed by bioinformatics indicated that the pathogenesis of DCM is mainly related to heart muscle contraction and calcium (Ca2+) release activation. In vitro, we discovered that high glucose treatment induced cardiomyocyte injury and exacerbated mitochondrial dysfunction remarkably. ConclusionOur research defined four crucial genes, as well as determined that mitochondrial function impairment compromises calcium homeostasis ultimately resulting in contractile dysfunction is a central contributor to DCM progression. Hopefully, this study will offer more effective biomarkers for DCM diagnosis and treatment.

Computational Discovery of Mitochondrial Dysfunction Biomarkers in Severe SARS-CoV-2 Infection: Facilitating Pytomedicine Screening

BackgroundCurrently, SARS-CoV-2 has not disappeared and continues to prevail worldwide, with the ongoing risk of mutations and the potential for severe COVID-19. The impairment of monocyte mitochondrial function caused by SARS-CoV-2, leading to a metabolic and immune dysregulation, is a crucial factor in the development of severe COVID-19. PurposeDiscover effective phytomedicines based on mitochondrial-related biomarkers in severe SARS-CoV-2 infection. MethodsFirstly, differential gene analysis and gene set enrichment analysis (GSEA) were conducted on monocytes datasets to identify genes and pathways distinguishing severe patients from uninfected individuals. Then, GO and KEGG enrichment analysis on the differentially expressed genes (DEGs) obtained. Take the DEGs and intersect them with the MitoCarta 3.0 gene set to obtain the differentially expressed mitochondrial-related genes (DE-MRGs). Subsequently, machine learning algorithms were employed to screen potential mitochondrial dysfunction biomarkers for severe COVID-19 based on score values. ROC curves were then plotted to assess the distinguish capability of the biomarkers, followed by validation using two additional independent datasets. Next, the effects of the identified biomarkers on metabolic pathways and immune cells were explored through Gene Set Variation Analysis (GSVA) and CIBERSORT. Finally, potential nature products for severe COVID-19 were screened from the expression profile dataset based on dysregulated mitochondrial-related genes, followed by in vitro experimental validation. ResultsThere are 1812 DEGs and 17 dysregulated mitochondrial processes between severe COVID-19 patients and uninfected individuals. A total of 77 DE-MRGs were identified, and the potential biomarkers were identified as RECQL4, PYCR1, PIF1, POLQ, and GLDC. In both the training and validation sets, the area under the ROC curve (AUC) for these five biomarkers was greater than 0.9. And they did not show significant changes in mild to moderate patients (P > 0.05), indicating their ability to effectively distinguish severe COVID-19. These biomarkers exhibit a highly significant correlation with the dysregulated metabolic processes (P < 0.05) and immune cell imbalance (P < 0.05) in severe patients, as demonstrated by GSVA and CIBERSORT algorithms. Curcumin has the highest score in the predictive model based on transcriptomic data from 496 natural compounds (P = 0.02; ES = 0.90). Pre-treatment with curcumin for 8 hours has been shown to alleviate mitochondrial membrane potential damage caused by the SARS-CoV-2 S1 protein (P < 0.05) and reduce elevated levels of reactive oxygen species (ROS) (P < 0.01). ConclusionThe results of this study indicate a significant correlation between severe SARS-CoV-2 infection and mitochondrial dysfunction. The proposed mitochondrial dysfunction biomarkers identified in this study are associated with the disease progression, metabolic and immune changes in severe SARS-CoV-2 infected patients. Curcumin has a potential role in preventing severe COVID-19 by protecting mitochondrial function. Our findings provide new strategies for predicting the prognosis and enabling early intervention in SARS-CoV-2 infection.

Exploring the link between pyrethroids exposure and dopaminergic degeneration through morphometric, immunofluorescence, and in-silico approaches: the therapeutic role of chitosan-encapsulated curcumin nanoparticles.

Introduction: The synthetic pyrethroid derivative fenpropathrin (FNE), a commonly used insecticide, has been associated with various toxic effects in mammals, particularly neurotoxicity. The study addressed the hallmarks of the pathophysiology of Parkinson's disease upon oral exposure to fenpropathrin (FNE), mainly the alteration of dopaminergic markers, oxidative stress, and molecular docking in rat models. In addition, the protective effect of curcumin-encapsulated chitosan nanoparticles (CRM-Chs-NPs) was also assessed. Methods: In a 60-day trial, 40 male Sprague Dawley rats were divided into 4 groups: Control, CRM-Chs-NPs (curcumin-encapsulated chitosan nanoparticles), FNE (15mg/kg bw), and FNE + CRM-Chs-NPs. Results: FNE exposure induced reactive oxygen species generation, ATP production disruption, activation of inflammatory and apoptotic pathways, mitochondrial function and dynamics impairment, neurotransmitter level perturbation, and mitophagy promotion in rat brains. Molecular docking analysis revealed that FNE interacts with key binding sites of dopamine synthesis and transport proteins. On the other hand, CRM-Chs-NPs mitigated FNE's toxic effects by enhancing mitochondrial dynamics, antioxidant activity, and ATP production and promoting anti-inflammatory and antiapoptotic responses. Conclusion: In summary, FNE appears to induce dopaminergic degeneration through various mechanisms, and CRM-Chs-NPs emerged as a potential therapeutic intervention for protecting the nervous tissue microenvironment.

Cardioprotection via mitochondrial transplantation supports fatty acid metabolism in ischemia-reperfusion injured rat heart.

In addition to cellular damage, ischemia-reperfusion (IR) injury induces substantial damage to the mitochondria and endoplasmic reticulum. In this study, we sought to determine whether impaired mitochondrial function owing to IR could be restored by transplanting mitochondria into the heart under ex vivo IR states. Additionally, we aimed to provide preliminary results to inform therapeutic options for ischemic heart disease (IHD). Healthy mitochondria isolated from autologous gluteus maximus muscle were transplanted into the hearts of Sprague-Dawley rats damaged by IR using the Langendorff system, and the heart rate and oxygen consumption capacity of the mitochondria were measured to confirm whether heart function was restored. In addition, relative expression levels were measured to identify the genes related to IR injury. Mitochondrial oxygen consumption capacity was found to be lower in the IR group than in the group that underwent mitochondrial transplantation after IR injury (p < 0.05), and the control group showed a tendency toward increased oxygen consumption capacity compared with the IR group. Among the genes related to fatty acid metabolism, Cpt1b (p < 0.05) and Fads1 (p < 0.01) showed significant expression in the following order: IR group, IR + transplantation group, and control group. These results suggest that mitochondrial transplantation protects the heart from IR damage and may be feasible as a therapeutic option for IHD.

Disrupted mitochondrial transcription factor A expression promotes mitochondrial dysfunction and enhances ocular surface inflammation by activating the absent in melanoma 2 inflammasome

PurposeSevere dry eye disease causes ocular surface damage, which is highly associated with mitochondrial dysfunction. Mitochondrial transcription factor A (TFAM) is essential for packaging mitochondrial DNA (mtDNA) and is crucial for maintaining mitochondrial function. Herein, we aimed to explore the effect of a decreased TFAM expression on ocular surface damage. MethodsFemale C57BL/6 mice were induced ocular surface injury by topical administrating benzalkonium chloride (BAC). Immortalized human corneal epithelial cells (HCECs) were stimulated by tert-butyl hydroperoxide (t-BHP) to create oxidative stress damage. HCECs with TFAM knockdown were established. RNA sequencing was employed to analyze the whole-genome expression. Mitochondrial changes were measured by transmission electron microscopy, Seahorse metabolic flux analysis, mitochondrial membrane potential, and mtDNA copy number. TFAM expression and inflammatory cytokines were determined using RT-qPCR, immunohistochemistry, immunofluorescence, and immunoblotting. ResultsIn both the corneas of BAC-treated mice and t-BHP-induced HCECs, we observed impaired TFAM expression, accompanied by mitochondrial structure and function defects. TFAM downregulation in HCECs suppressed mitochondrial respiratory capacity, reduced mtDNA content, induced mtDNA leakage into the cytoplasm, and led to inflammation. RNA sequencing revealed the absent in melanoma 2 (AIM2) inflammasome was activated in the corneas of BAC-treated mice. The AIM2 inflammasome activation was confirmed in TFAM knockdown HCECs. TFAM knockdown in t-BHP-stimulated HCECs aggravated mitochondrial dysfunction and the AIM2 inflammasome activation, thereby further triggering the secretion of inflammatory factors such as interleukin (IL) -1β and IL-18. ConclusionsTFAM reduction impaired mitochondrial function, activated AIM2 inflammasome and promoted ocular surface inflammation, revealing an underlying molecular mechanism for ocular surface disorders.

FOXK2 targeting by the SCF-E3 ligase subunit FBXO24 for ubiquitin mediated degradation modulates mitochondrial respiration

FOXK2 is a crucial transcription factor implicated in a wide array of biological activities and yet understanding of its molecular regulation at the level of protein turnover is limited. Here we identify that FOXK2 undergoes degradation in lung epithelia in the presence of the virulent pathogens P. aeruginosa and K. pneumoniae through ubiquitin-proteasomal processing. FOXK2 through its carboxyl-terminus (aa 428-478) binds the Skp-Cullin-F-box ubiquitin E3 ligase subunit FBXO24 that mediates multisite polyubiquitylation of the transcription factor resulting in its nuclear degradation. FOXK2 was detected within mitochondria and targeted depletion of the transcription factor or cellular expression of FOXK2 mutants devoid of key carboxyl-terminal domains significantly impaired mitochondrial function. In experimental bacterial pneumonia, Fbxo24 heterozygous mice exhibited preserved mitochondrial function and Foxk2 protein levels compared to wild-type littermates. The results suggest a new mode of regulatory control of mitochondrial energetics through modulation of FOXK2 cellular abundance.

Proteomics Approach to Identify Anthracycline-induced Cardiotoxicity Mechanisms in Human Cardiac Fibroblasts

Doxorubicin-induced cardiotoxicity (DIC) is a major life-threatening side-effect of chemotherapy in cancer patients. DIC leading to heart failure is caused by numerous mechanisms, including impaired mitochondrial function, disruption of calcium homeostasis, and altered gene and protein response that triggers cell death and, eventually, fibrosis. We performed a preliminary investigation of the effect of doxorubicin (DOX) on the cardiac fibroblast proteome using mass-spectrometry. Quantitative analysis showed significantly altered expression of 186 proteins. Nine out of forty-two Dox-upregulated proteins and seventeen out of twenty-four Dox-downregulated proteins showed a reciprocal trend in expression upon inhibiting a structural scaffold protein involved in cardiac calcium channel regulation. Overall, our data suggests the involvement of pathways in regulating mitochondrial energy metabolism, matrix remodeling, cell cycle/arrest, and cell survival via Rho/Rac nuclear exchanger proteins. DIC is multifactorial, and based on our pilot data, modulation of calcium channel regulators may be a promising strategy to mitigate the progression of DIC to heart failure. Research support received from the American Heart Association, NIH and the University of Arkansas for Medical Sciences. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Postovulatory Aging of Mouse Oocytes Impairs Offspring Behavior by Causing Oxidative Stress and Damaging Mitochondria.

Information on long-term effects of postovulatory oocyte aging (POA) on offspring is limited. Whether POA affects offspring by causing oxidative stress (OS) and mitochondrial damage is unknown. Here, in vivo-aged (IVA) mouse oocytes were collected 9 h after ovulation, while in vitro-aged (ITA) oocytes were obtained by culturing freshly ovulated oocytes for 9 h in media with low, moderate, or high antioxidant potential. Oocytes were fertilized in vitro and blastocysts transferred to produce F1 offspring. F1 mice were mated with naturally bred mice to generate F2 offspring. Both IVA and the ITA groups in low antioxidant medium showed significantly increased anxiety-like behavior and impaired spatial and fear learning/memory and hippocampal expression of anxiolytic and learning/memory-beneficial genes in both male and female F1 offspring. Furthermore, the aging in both groups increased OS and impaired mitochondrial function in oocytes, blastocysts, and hippocampus of F1 offspring; however, it did not affect the behavior of F2 offspring. It is concluded that POA caused OS and damaged mitochondria in aged oocytes, leading to defects in anxiety-like behavior and learning/memory of F1 offspring. Thus, POA is a crucial factor that causes psychological problems in offspring, and antioxidant measures may be taken to ameliorate the detrimental effects of POA on offspring.