Mitochondrial Oxidative Stress Research Articles

Nicotine aggravates pancreatic fibrosis in mice with chronic pancreatitis via mitochondrial calcium uniporter.

This study aimed to investigate the effects of nicotine on the activation of pancreatic stellate cells (PSCs) and pancreatic fibrosis in chronic pancreatitis (CP), along with its underlying molecular mechanisms. This was an in vivo and in vitro study. In vitro, PSCs were cultured to study the effects of nicotine on their activation and oxidative stress. Transcriptome sequencing was performed to identify potential signaling pathways involved in nicotine action. And the impact of nicotine on mitochondrial Ca2+ levels and Ca2+ transport-related proteins in PSCs was analyzed. The changes in nicotine effects were observed after the knockdown of the mitochondrial calcium uniporter (MCU) in PSCs. In vivo experiments were conducted using a mouse model of CP to assess the effects of nicotine on pancreatic fibrosis and oxidative stress in mice. The alterations in nicotine effects were observed after treatment with the MCU inhibitor Ru360. In vitro experiments demonstrated that nicotine promoted PSCs activation, characterized by increased cell proliferation, elevated α-SMA and collagen expression. Nicotine also increased the production of reactive oxygen species (ROS) and cellular malondialdehyde (MDA), exacerbating oxidative stress damage. Transcriptome sequencing revealed that nicotine may exert its effects through the calcium signaling pathway, and it was verified that nicotine elevated mitochondrial Ca2+ levels and upregulated MCU expression. Knockdown of MCU reversed the effects of nicotine on mitochondrial calcium homeostasis, improved mitochondrial oxidative stress damage and structural dysfunction, thereby alleviating the activation of PSCs. In vivo validation experiments showed that nicotine significantly aggravated pancreatic fibrosis in CP mice, promoted PSCs activation, exacerbated pancreatic tissue oxidative stress, and increased MCU expression. However, treatment with Ru360 significantly mitigated these effects. This study confirms that nicotine upregulates the expression of MCU, leading to mitochondrial calcium overload and exacerbating oxidative stress in PSCs, and ultimately promoting PSCs activation and exacerbating pancreatic fibrosis in CP.

DKK3 promotes renal fibrosis by increasing MFF-mediated mitochondrial dysfunction in Wnt/β-catenin pathway-dependent manner

Background Chronic kidney disease (CKD) lacks effective treatments and renal fibrosis (RF) is one of CKD’s outcomes. Dickkopf 3 (DKK3) has been identified as an agonist in CKD. However, the underlying mechanisms of DKK3 in CKD are not fully understood. Methods H2O2-treated HK-2 cells and ureteric obstruction (UUO) mice were used as RF models. Biomarkers, Masson staining, PAS staining, and TUNEL were used to assess kidney function and apoptosis. Oxidative stress and mitochondria function were also evaluated. CCK-8 and flow cytometry were utilized to assess cell viability and apoptosis. Western blotting, IHC, and qRT-PCR were performed to detect molecular expression levels. Immunofluorescence was applied to determine the subcellular localization. Dual luciferase assay, MeRIP, RIP, and ChIP were used to validate the m6A level and the molecule interaction. Results DKK3 was upregulated in UUO mouse kidney tissue and H2O2-treated HK-2 cells. Knockdown of DKK3 inhibited oxidative stress, maintained mitochondrial homeostasis, and alleviated kidney damage and RF in UUO mice. Furthermore, DKK3 silencing suppressed HK-2 cell apoptosis, oxidative stress, and mitochondria fission. Mechanistically, DKK3 upregulation was related to the high m6A level regulated by METTL3. DKK3 activated TCF4/β-catenin and enhanced MFF transcriptional expression by binding to its promoter. Overexpression of MFF reversed in the inhibitory effect of DKK3 knockdown on cell damage. Conclusion Upregulation of DKK3 caused by m6A modification activated the Wnt/β-catenin pathway to increase MFF transcriptional expression, leading to mitochondrial dysfunction and oxidative stress, thereby promoting RF progression.

Bu zhong Yiqi Decoction ameliorates mild cognitive impairment by improving mitochondrial oxidative stress damage via the SIRT3/MnSOD/OGG1 pathway

Ethnopharmacological relevanceBu-Zhong-Yi-Qi Decoction(BZYQD) is a traditional formula commonly used in China, known for its effects in tonifying Qi and raising Yang. It can relieve symptoms of cognitive impairment such as forgetfulness and lack of concentration caused by qi deficiency, which is common in aging and debilitating. However, much of the current research on BZYQD has been focused on its impact on the digestive system, leaving its molecular mechanisms in improving cognitive function largely unexplored. Aim of the studyCognitive decline in the aging central nervous system is intrinsically linked to oxidative damage. This study aims to investigate the therapeutic mechanism of BZYQD in treating mild cognitive impairment caused by qi deficiency, particularly through repair of mitochondrial oxidative damage. Materials and methodsA rat model of mild cognitive impairment (MCI) was established by administering reserpine subcutaneously for two weeks, followed by a two-week treatment with BZYQD/GBE. In vitro experiments were conducted to assess the effects of BZYQD on neuronal cells using a H2O2-induced oxidative damage model in PC12 cells. The open field test and the Morris water maze test evaluated the cognitive and learning memory abilities of the rats. HE staining and TEM were employed to observe morphological changes in the hippocampus and its mitochondria. Mitochondrial activity, ATP levels, and cellular viability were measured using assay kits. Protein expression in the SIRT3/MnSOD/OGG1 pathway was analyzed in tissues and cells through western blotting. Levels of 8-OH-dG in mitochondria extracted from tissues and cells were quantified using ELISA. Mitochondrial morphology in PC12 cells was visualized using Mito Red, and mitochondrial membrane potential was assessed using the JC-1 kit. ResultsBZYQD treatment significantly improved cognitive decline caused by reserpine in rats, as well as enhanced mitochondrial morphology and function in the hippocampus. Our findings indicate that BZYQD mitigates mtDNA oxidative damage in rats by modulating the SIRT3/MnSOD/OGG1 pathway. In PC12 cells, BZYQD reduced oxidative damage to mitochondria and mtDNA in H2O2-induced conditions and was associated with changes in the SIRT3/MnSOD/OGG1 pathway. ConclusionBZYQD effectively counteracts reserpine-induced mild cognitive impairment and ameliorates mitochondrial oxidative stress damage through the SIRT3/MnSOD/OGG1 pathway.

Transcriptome analysis reveals the mechanism of antifungal peptide epinecidin-1 against Botrytis cinerea by mitochondrial dysfunction and oxidative stress

The marine antifungal peptide epinecidin-1 (EPI) have been shown to inhibit Botrytis cinerea growth, while the molecular mechanism have not been explored based on omics technology. This study aimed to investigate the molecular mechanism of EPI against B. cinerea by transcriptome technology. Our findings indicated that a total of 1671 differentially expressed genes (DEGs) were detected in the mycelium of B. cinerea treated with 12.5 μmol/L EPI for 3 h, including 773 up-regulated genes and 898 down-regulated genes. Cluster analysis showed that DEGs (including steroid biosynthesis, (unsaturated) fatty acid biosynthesis) related to cell membrane metabolism were significantly down-regulated, and almost all DEGs involved in DNA replication were significantly inhibited. In addition, it also induced the activation of stress-related pathways, such as the antioxidant system, ATP-binding cassette transporter (ABC) and MAPK signaling pathways, and interfered with the tricarboxylic acid (TCA) cycle and oxidative phosphorylation pathways related to mitochondrial function. The decrease of mitochondrial related enzyme activities (succinate dehydrogenase, malate dehydrogenase and adenosine triphosphatase), the decrease of mitochondrial membrane potential and the increase content of hydrogen peroxide further confirmed that EPI treatment may lead to mitochondrial dysfunction and oxidative stress. Based on this, we speculated that EPI may impede the growth of B. cinerea through its influence on gene expression, and may lead to mitochondrial dysfunction and oxidative stress.

Dantrolene alleviates mitochondrial dysfunction and neuroinflammation in traumatic brain injury by modulating the NF-ĸβ/Akt pathway

Traumatic brain injury (TBI) triggers a bevy of changes including mitochondrial dysfunction, apoptosis, oxidative stress, neurobehavioural impairment, and neuroinflammation, among others. Dantrolene (DNT), a muscle relaxant which inhibits intracellular Ca2+ signaling from the ER, has been repurposed as a potential neuroprotective agent in various neurological diseases. However, there have been limited studies on whether it can mitigate TBI-induced deficits and restore impaired mitochondrial dynamics. This study sought to evaluate whether Dantrolene can potentially provide neuroprotection in an in vivo model of TBI. Male wistar rats subjected to TBI were treated with DNT (10 mg/kg) 1 h and 12 h post surgery. Animals were assessed 24 h post-TBI to evaluate neurobehavioural deficits and cerebral edema. We evaluated the protein expressions of apoptotic, autophagic, and neuroinflammatory markers by immunoblotting, as well as Mitochondrial Membrane Potential (MMP) and Reactive Oxygen Species (ROS) via Flow Cytometry to ascertain the effects of DNT on TBI. We further analysed immunofluorescence staining with Glial Fibrillary Acidic Protein (GFAP) and immunohistochemistry with NF-κβ to investigate neuroinflammation. H&E staining was also performed post-TBI. Our findings revealed DNT administration inhibits mitochondria-mediated apoptotis and reduces heightened oxidative stress. DNT treatment was also found to reverse neurobehavioural impairments and offer neuroprotection by preserving neuronal architechture. We also demonstrated that DNT inhibits neuronal autophagy and alleviates neuroinflammation following TBI by modulating the NF-κβ/Akt signaling pathway. Thus, our results suggest a novel application of DNT in ameliorating the multitude of deficits induced by TBI, thereby conferring neuroprotection.

Tobacco toxins trigger bone marrow mesenchymal stem cells aging by inhibiting mitophagy

Smoking disrupts bone homeostasis and serves as an independent risk factor for the development and progression of osteoporosis. Tobacco toxins inhibit the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), promote BMSCs aging and exhaustion, but the specific mechanisms are not yet fully understood. Herein, we successfully established a smoking-related osteoporosis (SROP) model in rats and mice through intraperitoneal injection of cigarette smoke extract (CSE), which significantly reduced bone density and induced aging and inhibited osteogenic differentiation of BMSCs both in vivo and in vitro. Bioinformatics analysis and in vitro experiments confirmed that CSE disrupts mitochondrial homeostasis through oxidative stress and inhibition of mitophagy. Furthermore, we discovered that CSE induced BMSCs aging by upregulating phosphorylated AKT, which in turn inhibited the expression of FOXO3a and the Pink1/Parkin pathway, leading to the suppression of mitophagy and the accumulation of damaged mitochondria. MitoQ, a mitochondrial-targeted antioxidant and mitophagy agonist, was effective in reducing CSE-induced mitochondrial oxidative stress, promoting mitophagy, significantly downregulating the expression of aging markers in BMSCs, restoring osteogenic differentiation, and alleviating bone loss and autophagy levels in CSE-exposed mice. In summary, our results suggest that BMSCs aging caused by the inhibition of mitophagy through the AKT/FOXO3a/Pink1/Parkin axis is a key mechanism in smoking-related osteoporosis.

Sex-dependent effects of chronic intermittent hypoxia: implication for obstructive sleep apnea

BackgroundObstructive sleep apnea (OSA) affects 10–26% of adults in the United States with known sex differences in prevalence and severity. OSA is characterized by elevated inflammation, oxidative stress (OS), and cognitive dysfunction. However, there is a paucity of data regarding the role of sex in the OSA phenotype. Prior findings suggest women exhibit different OSA phenotypes than men, which could result in under-reported OSA prevalence in women. To examine the relationship between OSA and sex, we used chronic intermittent hypoxia (CIH) to model OSA in rats. We hypothesized that CIH would produce sex-dependent phenotypes of inflammation, OS, and cognitive dysfunction, and these sex differences would be dependent on mitochondrial oxidative stress (mtOS).MethodsAdult male and female Sprague Dawley rats were exposed to CIH or normoxia for 14 days to examine the impact of sex on CIH-associated circulating inflammation (IL-1β, IL-6, IL-10, TNF-α), circulating steroid hormones, circulating OS, and behavior (recollective and spatial memory; gross and fine motor function; anxiety-like behaviors; and compulsive behaviors). Rats were implanted with osmotic minipumps containing either a mitochondria-targeting antioxidant (MitoTEMPOL) or saline vehicle 1 week prior to CIH initiation to examine how inhibiting mtOS would affect the CIH phenotype.ResultsSex-specific differences in CIH-induced inflammation, OS, motor function, and compulsive behavior were observed. In female rats, CIH increased inflammation (plasma IL-6 and IL-6/IL-10 ratio) and impaired fine motor function. Conversely, CIH elevated circulating OS and compulsivity in males. These sex-dependent effects of CIH were blocked by inhibiting mtOS. Interestingly, CIH impaired recollective memory in both sexes but these effects were not mediated by mtOS. No effects of CIH were observed on spatial memory, gross motor function, or anxiety-like behavior, regardless of sex.ConclusionsOur results indicate that the impact of CIH is dependent on sex, such as an inflammatory response and OS response in females and males, respectively, that are mediated by mtOS. Interestingly, there was no effect of sex or mtOS in CIH-induced impairment of recollective memory. These results indicate that mtOS is involved in the sex differences observed in CIH, but a different mechanism underlies CIH-induced memory impairments.

Targeting Mitochondrial Oxidative Stress to Protect Against Preterm Birth and Fetal Brain Injury via Nrf2 Induction.

Aims: Preterm birth (PTB), recognized as delivery before 37 weeks of gestation, is a multifactorial syndrome characterizing as the main cause of neonatal mortality. Reactive oxygen species (ROS) have been identified as proinflammatory factors to cause placental inflammation, thereby resulting in several pregnancy outcomes. To date, limited knowledge regarding the underlying mechanisms of ROS-induced PTB has been reported. In this study, we aimed to investigate the role of oxidative stress in PTB and the protective effects of mitochondria-targeted antioxidant MitoTEMPO (MT) on preterm labor and offspring mice. Results: In this study, we found that preterm placentas had abnormal mitochondrial function, oxidative stress, and inflammatory response. In the lipopolysaccharide (LPS)-induced PTB mouse model, MT inhibited PTB by ameliorating maternal oxidative stress and inflammation, especially in placentas, thus improving placental function to maintain pregnancy. Antenatal administration of MT prevented LPS-induced fetal brain damage in acute phase and improved long-term neurodevelopmental impairments. Furthermore, our in vitro investigations validated that MT retarded the ROS accumulation and inflammatory response in LPS-stimulated trophoblast cells by promoting Kelch-like ECH-associated protein 1 (Keap1) degradation and subsequently activating nuclear factor erythroid 2-related factor 2 (Nrf2). By inhibiting Nrf2 activation, we discovered that the anti-inflammation and protective characteristics of MT were Nrf2/ARE pathway dependent. Innovation and Conclusion: MT inhibited PTB and fetal brain injury by inhibiting maternal inflammation and improving placental function through Keap1/Nrf2/antioxidant response element signaling pathway. Our findings provide a novel therapeutic strategy for PTB.

Ultrasound‑targeted microbubble destruction technology delivering β‑klotho to the heart enhances FGF21 sensitivity and attenuates heart remodeling post‑myocardial infarction.

Fibroblast growth factor (FGF)21 is a peptide hormone that improves mitochondrial function and energy metabolism, and the deficiency of its co‑receptor β‑klotho (KLB) causes decreased FGF21 sensitivity. The present study examined whether the cardiac delivery of plasmids containing the KLB gene via ultrasound‑targeted microbubble destruction (UTMD) enhances the efficacy of FGF21 against heart failure post‑acute myocardial infarction (AMI). For this purpose, the levels of FGF21 in patients and rats with heart dysfunction post‑infarction were determined using ELISA. Sprague‑Dawley rats received the 3X UTMD‑mediated delivery of KLB@cationic microbubbles (KLB@CMBs) 1 week following the induction of AMI. Echocardiography, histopathology and biochemical analysis were performed at 4 weeks following the induction of AMI. The results revealed that patients with heart failure post‑infarction had higher serum FGF21 levels than the healthy controls. However, the downstream signal, KLB, but not α‑klotho, was reduced in the heart tissues of rats with AMI. As was expected, treatment with FGF21 did not substantially attenuate heart remodeling post‑infarction. It was found that decreased receptors KLB in the heart may result in the insensitivity to FGF21 treatment. In vivo, the UTMD technology‑mediated delivery of KLB@CMBs to the heart significantly enhanced the effects of FGF21 administration on cardiac remodeling and mitochondrial dysfunction in the rats following infarction. The delivery of KLB to the heart by UTMD and the administration of FGF21 attenuated mitochondrial impairment and oxidative stress by activating nuclear factor erythroid 2‑related factor 2 signals. On the whole, the present study demonstrates that the cardiac delivery of KLB significantly optimizes the cardioprotective effects of FGF21 therapy on adverse heart remodeling. UTMD appears a promising interdisciplinary approach with which to improve heart failure post‑myocardial infarction.

ACSM1 and ACSM3 regulate fatty acid metabolism to support prostate cancer growth and constrain ferroptosis.

Solid tumors are highly reliant on lipids for energy, growth, and survival. In prostate cancer, the activity of the androgen receptor (AR) is associated with reprogramming of lipid metabolic processes. Here, we identified acyl-CoA synthetase medium chain family members 1 and 3 (ACSM1 and ACSM3) as AR-regulated mediators of prostate cancer metabolism and growth. ACSM1 and ACSM3 were upregulated in prostate tumors compared to non-malignant tissues and other cancer types. Both enzymes enhanced proliferation and protected prostate cancer cells from death in vitro, while silencing ACSM3 led to reduced tumor growth in an orthotopic xenograft model. ACSM1 and ACSM3 were major regulators of the prostate cancer lipidome and enhanced energy production via fatty acid oxidation. Metabolic dysregulation caused by loss of ACSM1/3 led to mitochondrial oxidative stress, lipid peroxidation and cell death by ferroptosis. Conversely, elevated ACSM1/3 activity enabled prostate cancer cells to survive toxic levels of medium chain fatty acids and promoted resistance to ferroptosis-inducing drugs and AR antagonists. Collectively, this study reveals a tumor-promoting function for medium chain acyl-CoA synthetases and positions ACSM1 and ACSM3 as key players in prostate cancer progression and therapy resistance.

TIN2-mediated reduction of mitophagy induces RPE senescence under high glucose

The telomere-associated protein TIN2 localizes to both telomeres and mitochondria. Nevertheless, the impact of TIN2 on retinal pigment epithelial (RPE) cells in diabetic retinopathy (DR) remains unclear. This research aims to examine the role of TIN2 in the senescence of RPE and its potential as a therapeutic target. Western blotting and immunofluorescence staining were utilized to identify TIN2 expression and mitophagy. RT-qPCR was employed to identify senescent associated secretory phenotype (SASP) in ARPE-19 cells infected with TIN2 overexpression. To examine mitochondria and the cellular senescence of RPE, TEM, SA-β-gal staining, and cell cycle analysis were used. The impact of TIN2 was examined using OCT and immunohistochemistry in mice. DHE staining and ZO-1 immunofluorescence were applied to detect RPE oxidative stress and tight junctions. Our research revealed that increased mitochondria-localized TIN2 aggravated the cellular senescence of RPE cells both in vivo and in vitro under hyperglycemia. TIN2 overexpression stimulated the mTOR signaling pathway in ARPE-19 cells and exacerbated the inhibition of mitophagy levels under high glucose, which can be remedied through the mTOR inhibitor, rapamycin. Knockdown of TIN2 significantly reduced senescence and mitochondrial oxidative stress in ARPE-19 cells under high glucose and restored retinal thickness and RPE cell tight junctions in DR mice. Our study indicates that increased mitochondria-localized TIN2 induced cellular senescence in RPE via compromised mitophagy and activated mTOR signaling. These results propose that targeting TIN2 could potentially serve as a therapeutic strategy in the treatment of DR.

Protection against Oxidative Stress by Coenzyme Q10 in a Porcine Retinal Degeneration Model.

Oxidative stress plays an important role in neurodegenerative diseases, including glaucoma. Therefore, we analyzed if the antioxidant coenzyme Q10 (CoQ10), which is also commercially available, can prevent retinal degeneration induced by hydrogen peroxide (H2O2) in a porcine organ culture model. Retinal explants were cultivated for eight days, and H2O2 (500 µM, 3 h) induced the oxidative damage. CoQ10 therapy was applied (700 µM, 48 h). Retinal ganglion cells (RGCs) and microglia were examined immunohistologically in all groups (control, H2O2, H2O2 + CoQ10). Cellular, oxidative, and inflammatory genes were quantified via RT-qPCR. Strong RGC loss was observed with H2O2 (p ≤ 0.001). CoQ10 elicited RGC protection compared to the damaged group at a histological (p ≤ 0.001) and mRNA level. We detected more microglia cells with H2O2, but CoQ10 reduced this effect (p = 0.004). Cellular protection genes (NRF2) against oxidative stress were stimulated by CoQ10 (p ≤ 0.001). Furthermore, mitochondrial oxidative stress (SOD2) increased through H2O2 (p = 0.038), and CoQ10 reduced it to control level. Our novel results indicate neuroprotection via CoQ10 in porcine retina organ cultures. In particular, CoQ10 appears to protect RGCs by potentially inhibiting apoptosis-related pathways, activating intracellular protection and reducing mitochondrial stress.

Coenzyme Q10 and Autoimmune Disorders: An Overview.

Some 90 autoimmune disorders have been described in medical literature, affecting most of the tissues within the body. Autoimmune disorders may be difficult to treat, and there is a need to develop novel therapeutic strategies for these disorders. Autoimmune disorders are characterised by mitochondrial dysfunction, oxidative stress, and inflammation; there is therefore a rationale for a role for coenzyme Q10 in the management of these disorders, on the basis of its key role in normal mitochondrial function, as an antioxidant, and as an anti-inflammatory agent. In this article, we have therefore reviewed the potential role of CoQ10, in terms of both deficiency and/or supplementation, in a range of autoimmune disorders.

Effect of Elamipretide on the Vitrification of Mouse Ovarian Tissue by Freezing.

The importance of ovarian cortical cryopreservation in fertility preservation is receiving increasing attention from reproductive specialists, and mitochondrial dysfunction is an important cause of reduced ovarian tissue cryopreservation. Elamipretide (SS-31) is a novel mitochondria-targeted antioxidant. However, whether it has a protective effect on mouse ovarian tissue cryopreservation remains to be studied. In this study, we examined follicular morphology and viability, mitochondrial function and oxidative stress levels, apoptosis, and culture in vitro after vitrification cryoresuscitation operation by treating ovarian tissues with SS-31 in cryoprotectant resuscitation solution. At the end of the experiment, the addition of 100 μmol/L SS-31 significantly improved follicle quality and oocyte maturation rate in vitro (p < 0.05) and significantly reduced apoptosis (p < 0.05) and oxidative stress levels (superoxide dismutase, catalase, malondialdehyde, p < 0.05). Meanwhile, mitochondrial respiratory chain complex enzyme activity, mtDNA copy number (p < 0.05), and adenosine triphosphate (p < 0.05) content were significantly increased in the 100 μmol/L SS-31-treated group. In addition, the mRNA expression levels of mitochondrial energy metabolism- and biosynthesis-related genes (STRT1, PGC-1a, PPAR-a, TFAM, p < 0.05) were markedly upregulated (p < 0.05) in the 100 μmol/L SS-31 group. In conclusion, SS-31 improved the cryopreservation of ovarian tissues, and 100 μmol/L SS-31 was found to be the most effective.

Replicating human characteristics: A promising animal model of central fatigue

Central fatigue is a common pathological state characterized by psychological loss of drive, lack of appetite, drowsiness, and decreased psychic alertness. The mechanism underlying central fatigue is still unclear, and there is no widely accepted successful animal model that fully represents human characteristics. We aimed to construct a more clinically relevant and comprehensive animal model of central fatigue. In this study, we utilized the Modified Multiple Platform Method (MMPM) combined with alternate-day fasting (ADF) to create the animal model. The model group rats are placed on a stationary water environment platform for sleep deprivation at a fixed time each day, and they were subjected to ADF treatment. On non-fasting days, the rats were allowed unrestricted access to food. This process was sustained over a period of 21 days. We evaluated the model using behavioral assessments such as open field test, elevated plus maze test, tail suspension test, Morris water maze test, grip strength test, and forced swimming test, as well as serum biochemical laboratory indices. Additionally, we conducted pathological observations of the hippocampus and quadriceps muscle tissues, transmission electron microscope observation of mitochondrial ultrastructure, and assessment of mitochondrial energy metabolism and oxidative stress-related markers. The results revealed that the model rats displayed emotional anomalies resembling symptoms of depression and anxiety, decreased exploratory behavior, decline in learning and memory function, and signs of skeletal muscle fatigue, successfully replicating human features of negative emotions, cognitive decline, and physical fatigue. Pathological damage and mitochondrial ultrastructural alterations were observed in the hippocampus and quadriceps muscle tissues, accompanied by abnormal mitochondrial energy metabolism and oxidative stress in the form of decreased ATP and increased ROS levels. In conclusion, our ADF+MMPM model comprehensively replicated the features of human central fatigue and is a promising platform for preclinical research. Furthermore, the pivotal role of mitochondrial energy metabolism and oxidative stress damage in the occurrence of central fatigue in the hippocampus and skeletal muscle tissues was corroborated.

Role of ghrelin hormone in the development of alcohol-associated liver disease

Fatty liver is the earliest response of the liver to excessive alcohol consumption. Previously we identified that chronic alcohol administration increases levels of stomach-derived hormone, ghrelin, which by reducing circulating insulin levels, ultimately contributes to the development of alcohol-associated liver disease (ALD). In addition, ghrelin directly promotes fat accumulation in hepatocytes by enhancing de novo lipogenesis. Other than promoting ALD, ghrelin is known to increase alcohol craving and intake. In this study, we used a ghrelin receptor (GHSR) knockout (KO) rat model to characterize the specific contribution of ghrelin in the development of ALD with emphasis on energy homeostasis. Male Wistar wild type (WT) and GHSR-KO rats were pair-fed the Lieber-DeCarli control or ethanol diet for 6 weeks. At the end of the feeding period, glucose tolerance test was conducted, and tissue samples were collected. We observed reduced alcohol intake by GHSR-KOs compared to a previous study where WT rats were fed ethanol diet ad libitum. Further, when the WTs were pair-fed to GHSR-KOs, the KO rats exhibited resistance to develop ALD through improving insulin secretion/sensitivity to reduce adipose lipolysis and hepatic fatty acid uptake/synthesis and increase fatty acid oxidation. Furthermore, proteomic data revealed that ethanol-fed KO exhibit less alcohol-induced mitochondrial dysfunction and oxidative stress than WT rats. Proteomic data also confirmed that the ethanol-fed KOs are insulin sensitive and are resistant to hepatic steatosis development compared to WT rats. Together, these data confirm that inhibiting ghrelin action prevent alcohol-induced liver and adipose dysfunction independent of reducing alcohol intake.

Mitochondrial CypD Acetylation Promotes Endothelial Dysfunction and Hypertension.

Nearly half of adults have hypertension, a major risk factor for cardiovascular disease. Mitochondrial hyperacetylation is linked to hypertension, but the role of acetylation of specific proteins is not clear. We hypothesized that acetylation of mitochondrial CypD (cyclophilin D) at K166 contributes to endothelial dysfunction and hypertension. To test this hypothesis, we studied CypD acetylation in patients with essential hypertension, defined a pathogenic role of CypD acetylation in deacetylation mimetic CypD-K166R mutant mice and endothelial-specific GCN5L1 (general control of amino acid synthesis 5 like 1)-deficient mice using an Ang II (angiotensin II) model of hypertension. Arterioles from hypertensive patients had 280% higher CypD acetylation coupled with reduced Sirt3 (sirtuin 3) and increased GCN5L1 levels. GCN5L1 regulates mitochondrial protein acetylation and promotes CypD acetylation, which is counteracted by mitochondrial deacetylase Sirt3. In human aortic endothelial cells, GCN5L1 depletion prevents superoxide overproduction. Deacetylation mimetic CypD-K166R mice were protected from vascular oxidative stress, endothelial dysfunction, and Ang II-induced hypertension. Ang II-induced hypertension increased mitochondrial GCN5L1 and reduced Sirt3 levels resulting in a 250% increase in GCN5L1/Sirt3 ratio promoting CypD acetylation. Treatment with mitochondria-targeted scavenger of cytotoxic isolevuglandins (mito2HOBA) normalized GCN5L1/Sirt3 ratio, reduced CypD acetylation, and attenuated hypertension. The role of mitochondrial acetyltransferase GCN5L1 in the endothelial function was tested in endothelial-specific GCN5L1 knockout mice. Depletion of endothelial GCN5L1 prevented Ang II-induced mitochondrial oxidative stress, reduced the maladaptive switch of vascular metabolism to glycolysis, prevented inactivation of endothelial nitric oxide, preserved endothelial-dependent relaxation, and attenuated hypertension. These data support the pathogenic role of CypD acetylation in endothelial dysfunction and hypertension. We suggest that targeting cytotoxic mitochondrial isolevuglandins and GCN5L1 reduces CypD acetylation, which may be beneficial in cardiovascular disease.

Revisiting airway epithelial dysfunction and mechanisms in chronic obstructive pulmonary disease: Role of mitochondrial damage.

Chronic exposure to environmental hazards causes airway epithelial dysfunction, primarily impaired physical barriers, immune dysfunction, and repair or regeneration. Impairment of airway epithelial function subsequently leads to exaggerated airway inflammation and remodeling, the main features of chronic obstructive pulmonary disease (COPD). Mitochondrial damage has been identified as one of the mechanisms of airway abnormalities in COPD, which is closely related to airway inflammation and airflow limitation. In this review, we evaluate updated evidence for airway epithelial mitochondrial damage in COPD and focus on the role of mitochondrial damage in airway epithelial dysfunction. In addition, the possible mechanism of airway epithelial dysfunction mediated by mitochondrial damage is discussed in detail, and recent strategies related to airway epithelial-targeted mitochondrial therapy are summarized. Results have shown that dysregulation of mitochondrial quality and oxidative stress may lead to airway epithelial dysfunction in COPD. This may result from mitochondrial damage as a central organelle mediating abnormalities in cellular metabolism. Mitochondrial damage mediates pro-cellular senescence effects due to mitochondrial reactive oxygen species, which effectively exacerbate different types of programmed cell death, participate in lipid metabolism abnormalities, and ultimately promote airway epithelial dysfunction and trigger COPD airway abnormalities. These can be prevented by targeting mitochondrial damage factors and mitochondrial transfer. Thus, because mitochondrial damage is involved in COPD progression as a central factor of homeostatic imbalance in airway epithelial cells, it may be a novel target for therapeutic intervention to restore airway epithelial integrity and function in COPD.

Protective Effect of Resveratrol Combined with Levodopa Against Oxidative Damage in Dopaminergic Neurons.

Levodopa (L-3,4-dihydroxyphenylalanine, L-Dopa) alleviates the symptoms of Parkinson's disease (PD), yet prolonged usage may give rise to severe adverse effects. Resveratrol (RSV) is a potent antioxidant, anticancer and anti-inflammatory agent. And a variety of polyphenol antioxidant compounds derived from RSV combined with levodopa have demonstrated neuroprotective activity against neuronal cell death. The purpose of this study was to examine the impact of this combination of RSV and L-Dopa on the survival rate, growth status, and reactive oxygen species (ROS) of MES23.5 dopamine (DA) neuron cells. In this study, we induced MPP+ in MES23.5 dopamine neuron cells and observed their survival rate, growth status, ROS content, as well as the effect of RSV combined with L-Dopa on cell survival. We also measured malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity levels as indicators of mitochondrial function, oxidative stress, and oxidative damage in the cells. Our results indicated that the MES23.5 dopamine neurons had decreased survival, poor growth status, and increased ROS content after MPP+ induction. Moreover, we found that MDA levels were elevated, and SOD activity levels were decreased, suggesting that the cells experienced abnormal mitochondrial function. However, when RSV was combined with L-Dopa, the cells showed a reduced level of MPP + -induced oxidative damage, with a more significant inhibitory effect observed in the RSV group at a concentration of 50 μmol/L. In conclusion, we found that the effects of co-administration of RSV with L-Dopa (100 μmol/L) was more effective than L-Dopa administered at the high dose. Thus, we found that RSV has the potential to reduce the dose of L-Dopa required to improve PD symptoms.

Fosgonimeton attenuates amyloid-beta toxicity in preclinical models of Alzheimer's disease

Positive modulation of hepatocyte growth factor (HGF) signaling may represent a promising therapeutic strategy for Alzheimer's disease (AD) based on its multimodal neurotrophic, neuroprotective, and anti-inflammatory effects addressing the complex pathophysiology of neurodegeneration. Fosgonimeton is a small-molecule positive modulator of the HGF system that has demonstrated neurotrophic and pro-cognitive effects in preclinical models of dementia. Herein, we evaluate the neuroprotective potential of fosgonimeton, or its active metabolite, fosgo-AM, in amyloid-beta (Aβ)-driven preclinical models of AD, providing mechanistic insight into its mode of action. In primary rat cortical neurons challenged with Aβ (Aβ1-42), fosgo-AM treatment significantly improved neuronal survival, protected neurite networks, and reduced tau hyperphosphorylation. Interrogation of intracellular events indicated that cortical neurons treated with fosgo-AM exhibited a significant decrease in mitochondrial oxidative stress and cytochrome c release. Following Aβ injury, fosgo-AM significantly enhanced activation of pro-survival effectors ERK and AKT, and reduced activity of GSK3β, one of the main kinases involved in tau hyperphosphorylation. Fosgo-AM also mitigated Aβ-induced deficits in Unc-like kinase 1 (ULK1) and Beclin-1, suggesting a potential effect on autophagy. Treatment with fosgo-AM protected cortical neurons from glutamate excitotoxicity, and such effects were abolished in the presence of an AKT or MEK/ERK inhibitor. In vivo, fosgonimeton administration led to functional improvement in an intracerebroventricular Aβ25-35 rat model of AD, as it significantly rescued cognitive function in the passive avoidance test. Together, our data demonstrate the ability of fosgonimeton to counteract mechanisms of Aβ-induced toxicity. Fosgonimeton is currently in clinical trials for mild-to-moderate AD (NCT04488419; NCT04886063).