Mitochondrial Function Research Articles

Fanlian Huazhuo Formula: A promising herbal preparation for metabolic liver disease

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) has increased significantly in recent decades and is projected to increase further due to the rising obesity rates. MASLD patients are at higher risk of developing advanced liver diseases “cirrhosis and hepatocellular carcinoma” as well as liver- or cardiovascular-related mortality. Existing lipid-lowering therapies failed to reduce the risk of mortality in these patients. Therefore, there is an urgent need for pharmacotherapies that can control and even reverse this disease. Fanlian Huazhuo Formula (FLHZF) is a combination herbal preparation, and its various individual constituents regulate hepatic lipid metabolism, adipose tissue inflammation, and gut microbiota. Despite, these useful effects, limited information is available on its benefits in diet-induced hepatosteatosis. In this article, we discuss the research findings recently published about the therapeutic effects of FLHZF in suppressing MASLD development and underlying mechanisms. Utilizing a series of in vitro and in vivo experiments, the authors demonstrated for the first time that FLHZF suppresses MASLD in male mice possibly by inhibiting hepatic de novo lipogenesis pathways and reducing hepatocyte death. This study paves the way for future investigations aimed at investigating FLHZF’s role in inhibiting lipogenesis particularly using radioactively-labeled glucose and acetate, and governing hepatocyte mitochondrial function, gut microbiome profile, and its effects in other models of MASLD, and female mice.

Mitochondrial function in patients affected with fibromyalgia syndrome is impaired and correlates with disease severity

Fibromyalgia is a musculoskeletal syndrome characterized by chronic widespread pain that is often associated with systemic manifestations. Since mitochondria are the main source of cellular energy, we hypothesized that fibromyalgia syndrome (FMS) could be linked to mitochondrial impairment. Aim was to study mitochondrial dysfunction in peripheral blood mononuclear cells isolated from 50 patients with primary FMS and 20 apparently healthy controls. Although no differences in mitochondrial basal respiration were observed between patients with primary FMS and healthy controls, a lower median bioenergetic health index (BHI; − 22.1%, p = 0.03), a proxy of mitochondrial function, was found in patients. According to fibromyalgia severity score (FSS), a composite of widespread pain index and symptom severity scale, a lower median BHI (− 18.7%) was found in patients with a FSS ≥ 20 compared to those with a FSS < 20. Negative moderate correlations were found only between BHI and FSS (r = − 0.36) and widespread pain index (r = − 0.38). We demonstrated that patients with FMS had an impaired mitochondrial function. Additionally, we found a mild correlation between the widespread pain index and the BHI, possibly indicating that the altered mitochondrial function, in these patients, narrows musculoskeletal rather than central nervous system involvement.

Phosphoenolpyruvate carboxylase (PEPC) is essential for the glycolytic pathway and parasite proliferation in Babesia gibsoni

Apicomplexan parasites predominantly generate ATP and lactic acid through glycolysis and anaerobic glucose metabolism, incorporating CO2 into glycolysis via a stage-dependent phosphoenolpyruvate carboxylase (PEPC) mechanism. Although the role of PEPC in plant and bacterial carbon fixation is well documented, its function within Babesia remains largely unexplored. This study employs reverse genetics to probe the biological role of PEPC in Babesia gibsoni, noting its conservation across similar protozoa, suggesting a pivotal and conserved biological function. Western blotting and immunofluorescence (IFA) experiments using the BgPEPC-3 × Flag strain revealed that the BgPEPC protein has a molecular weight of 105 kDa and localizes predominantly to the cytoplasm. Attempts to knock out the PEPC gene in BgPEPC-3 × Flag strains failed under standard media conditions, succeeded only with the addition of 5 mM malate, an upstream metabolite of oxaloacetic acid (OAA). In addition to malate, the downstream metabolite of OAA can also partially compensate for the phenotypic defects caused by PEPC deficiency. This intervention alleviated severe growth deficits, underscoring the critical role of aspartate in the parasite lifecycle. Moreover, metabolic inhibitors such as L-cycloserine and triazamidine, which target aspartate aminotransferase and mitochondrial functions, respectively, demonstrated increased efficacy against BgPEPC knockout strains. The lack of a compensatory response to malic acid supplementation underscores the integral role of BgPEPC in intermediary carbon metabolism and its necessity in providing aspartate as a precursor to pyrimidine synthesis. Collectively, these findings suggest that PEPC could be a potential target for future drug development against B. gibsoni infections.Graphical

Injectable Hierarchical Bioactive Hydrogels with Fibroblast Growth Factor 21/Edaravone/Caffeic Acid Asynchronous Delivery for Treating Parkinson's Disease.

Parkinson's disease (PD) is one of the most common long-term neurodegenerative disorders, with multiple comorbid psychiatric and behavioral abnormalities. The combination of clinical drugs targeting different symptoms with smart hydrogels to achieve asynchronous releases is highly translational and challenging. Here, a hierarchical bioactive hydrogel (OACDP) is designed with asynchronous release based on PD pathology. The hydrogel with caffeic acid-grafted polymer main chain is crosslinked using a micellar nanocrosslinker, with sufficient modulus (≈167Pa), antioxidant activity (>50%), injectability (30-gauge syringe needle), and shape-adaptability. Each of the three drugs (caffeic acid, fibroblast growth factor 21, and Edaravone) is separately engaged in different micro- or nanostructures of the hydrogel and released with asynchronous kinetics of first-order release, zero-order release, or matching Korsmeyer-Peppas model. The triple-loaded hydrogel is injected into the brains of PD rats, showing behavioral improvement. Histological analysis revealed that the triple-loaded OACDP hydrogels are effective in achieving immediate neuroprotection, i.e., reduction the loss of tyrosine hydroxylase in substantia nigra compacta and striatum (retained ≈10-fold versus control), decreasing oxidative stress, reducing astrocyte and microglia activation, and stimulating the AMPK/PGC-1α axis to regulate the mitochondrial function, providing a multi-dimensional PD therapy. The asynchronous release of OACDP hydrogel provides a new conception for PD treatment and other neurodegenerative diseases.

PACS2/CPT1A/DHODH signaling promotes cardiomyocyte ferroptosis in diabetic cardiomyopathy

ObjectivesThe pathophysiology of diabetic cardiomyopathy (DCM) is a phenomenon of great interest, but its clinical problems have not yet been effectively addressed. Recently, the mechanism of ferroptosis in the pathophysiology of various diseases, including DCM, has attracted widespread attention. Here, we explored the role of PACS2 in ferroptosis in DCM through its downregulation of PACS2 expression.Methods and resultsCardiomyocytes were treated with high glucose and palmitic acid (HGPA), and the detection of cardiomyocyte iron ions, lipid peroxides, and reactive oxygen species (ROS) revealed clear ferroptosis during these treatments. Silencing PACS2 downregulated CPT1A expression and upregulated DHODH expression significantly, reversing HGPA-induced ferroptosis. Further silencing of PACS2 with a CPT1A agonist exacerbated cardiomyocyte ferroptosis while promoting mitochondrial damage in cardiomyocytes. Using a mouse model of type 2 diabetes induced by streptozotocin (STZ) and a high-fat diet (HFD), we found that PACS2 deletion reversed these treatment-induced increases in cellular iron ions, impaired cardiac function, mitochondrial damage and ferroptosis in cardiac muscle tissues.ConclusionsThe PACS2/CPT1A/DHODH signalling pathway may be involved in ferroptosis in DCM by regulating cardiomyocyte mitochondrial function.

FRK exerts oncogenic effects by targeting NQO2 via exosomal miR-9-3p to regulate mitochondrial function.

The role of Fyn-related kinase (FRK) in promoting tumor progression and metabolism in non-small cell lung cancer (NSCLC) has been demonstrated in our earlier study, and here we further explored whether exosome could serve as a key player in the relevant regulatory mechanism. Exosomes were isolated from the culture medium of FRK-knockout (KO) cells and co-cultured with NSCLC cells, showing negative effects on cell proliferation, metastasis, metabolism, and mitochondrial function. Exosomal miR-9-3p was selected as an intermediate messenger through microRNA (miRNA) sequencing. The miR-9-3p inhibitor and exosome inhibitor GW4869 were then applied in the co-culture system to verify the contribution of exosomal miR-9-3p to cell malignant phenotype and mitochondrial function. Moreover, NQO2, a potential target of exosomal miR-9-3p, was also suggested to be involved in the regulation of mitochondrial functional status. In brief, this study revealed a novel molecular mechanism by which FRK promotes the malignant progression of NSCLC by targeting NQO2 via exosomal miR-9-3p to strengthen mitochondrial function.

Proteomics analysis in rats reveals convergent mechanisms between major depressive disorder and dietary zinc deficiency

Abstract Background Preclinical and clinical studies have shown that dietary zinc deficiency can lead to symptoms similar to those observed in major depressive disorder (MDD). However, the underlying molecular mechanisms remain unclear. To investigate these mechanisms, we examined proteomic changes in the prefrontal cortex (PFC) and hippocampus (HP) of rats, two critical brain regions implicated in the pathophysiology of depression. Methods Rats were fed diets either adequate in zinc (ZnA, 50 mg Zn/kg) or deficient in zinc (ZnD, &lt;3 mg/kg) for four weeks. High-throughput proteomic analysis was used to detect changes in protein expression, supplemented by enzyme activity assay for mitochondrial complexes I and IV, examining their functional impacts. Results ZnD led to significant alterations in protein expression related to zinc transport and mitochondrial function. Proteomic analysis revealed changes in zinc transporter family members such as Slc30a1 (6.64 log2FC), Slc30a3 (-2.32 log2FC), Slc30a4 (2.87 log2FC), Slc30a5 (5.90 log2FC), Slc30a6 (1.50 log2FC), and Slc30a7 (2.17 log2FC) in the PFC, and Slc30a3 (-1.02 log2FC), Slc30a5 (-1.04 log2FC), and Slc30a7 (1.08 log2FC) in the HP of rats subjected to ZnD. Furthermore, ZnD significantly affected essential mitochondrial activity proteins, including Atp5pb (3.25 log2FC), Cox2 (2.28 log2FC), Atp5me (2.04 log2FC), Cyc1 (2.30 log2FC), Cox4i1 (1.23 log2FC), Cox7c (1.63 log2FC), and Cisd1 (1.55 log2FC), with a pronounced decrease in complex I activity in the PFC. Conclusions Our study demonstrates that ZnD leads to significant proteomic changes in the PFC and HP of rats. Specifically, ZnD alters the expression of zinc transporter proteins and proteins critical for mitochondrial function. The significant decrease in complex I activity in the PFC further underscores the impact of ZnD on mitochondrial function. These results highlight the molecular mechanisms by which ZnD can influence brain function and contribute to symptoms similar to those observed in depression.

Nicotinamide riboside targets mitochondrial unfolded protein response to reduce alcohol-induced damage in Kupffer cells.

The pathogenesis of alcohol-related liver disease (ALD) is closely linked to mitochondrial dysfunction and impaired cellular energy metabolism. In this study, we explored how ethanol triggers inflammation, oxidative stress, and mitochondrial dysfunction in Kupffer cells, i.e.hepatic resident macrophages, primarily focusing on the mitochondrial unfolded protein response (UPRmt) using immortalized mouse Kupffer cells (ImKCs) and mouse primary KCs. The UPRmt is a cellular defense mechanism activated in response to the perturbation of mitochondrial proteostasis to maintain mitochondrial integrity and function by upregulating the expression of mitochondrial chaperones and proteases. We also determined whether nicotinamide riboside (NR), a NAD+ precursor, could mitigate ethanol-triggered cellular damage. When ImKCs were exposed to 80 mm ethanol for 72 h, they displayed inflammation, oxidative stress, and impaired mitochondrial function with decreased mitochondrial content and deformed mitochondrial crista structure. NR, however, counteracted the effects of ethanol. Furthermore, ethanol increased mRNA and protein levels of UPRmt genes, such as mitochondrial chaperones and proteases, which were attenuated by NR. Notably, the ethanol-induced shift in the entry of activating transcription factor 5 (ATF5), a putative transcriptional regulator of UPRmt, to the nucleus from the mitochondria was abolished by NR. The induction of UPRmt genes by ethanol was significantly repressed when Atf5 was knocked down, indicating the role of ATF5 in the induction of UPRmt genes in ImKCs exposed to ethanol. We also confirmed the induction of UPRmt gene expression in mouse and human livers exposed to alcohol. Our findings demonstrate the ability of NR to alleviate ethanol-induced oxidative stress, inflammation, and mitochondrial dysfunction, partly by modulating the ATF5-dependent UPRmt pathway in ImKCs, suggesting its potential for ALD therapy. © 2024 The Pathological Society of Great Britain and Ireland.

The effect of trimetazidine on cardiac haemodynamics and mitochondrial function in wild-type transthyretin amyloidosis.

Wild-type transthyretin cardiac amyloidosis (ATTRwt) is a cardiomyopathy causing myocardial hypoperfusion and impaired cardiac mitochondrial function. Trimetazidine is an antianginal agent used in patients with stable angina pectoris, which improves cardiac contractility and mitochondrial function. The aim of the study was to investigate the effect of trimetazidine on invasive haemodynamics and cardiac mitochondrial function in ATTRwt. In a randomized, double-blind, placebo-controlled, crossover trial, 22 patients with ATTRwt received 4weeks of trimetazidine and placebo in randomized order. After each treatment period followed examinations with endomyocardial biopsies taken for high-resolution respirometry and right heart catheterization at rest and during a cardiopulmonary exercise test. The primary endpoint was mean pulmonary artery wedge pressure (mPAWP) during peak exercise. The secondary endpoint was cardiac mitochondrial oxidative phosphorylation capacity. Exploratory endpoints were echocardiographic parameters, cardiac biomarker levels and quality of life. Trimetazidine did not significantly reduce mPAWP during peak exercise (31±12 vs. 31±13mmHg, P=0.61) or improve the cardiac mitochondrial oxidative phosphorylation capacity (73.4±7.7 vs. 75.3±7.7pmol O2/(mg*s), P=0.81) compared with placebo, nor did treatment with trimetazidine improve ejection fraction (P=0.93), global longitudinal strain (P=0.23), N-terminal pro-brain natriuretic peptide (NT-proBNP) levels (P=0.92) or the patients' quality of life (P=0.98). In ATTRwt, treatment with trimetazidine did not improve mPAWP or cardiac mitochondrial oxidative phosphorylation capacity compared with placebo.

TIFAB Modulates Metabolic Pathways in KMT2A::MLLT3-Induced AML Through HNF4A.

TRAF-interacting protein with forkhead-associated domain B (TIFAB), an inhibitor of NF-kB signaling, plays critical roles in hematopoiesis, myelodysplastic neoplasms, and leukemia. We previously demonstrated that Tifab enhances KMT2A::MLLT3-driven acute myeloid leukemia (AML) by either upregulating Hoxa9 or through ubiquitin-specific peptidase 15 (USP15)-mediated downregulation of p53 signaling. In this study, we show that Tifab deletion in KMT2A::MLLT3-induced AML impairs leukemia stem/progenitor cell (LSPC) engraftment, glucose uptake, and mitochondrial function. Gene Set Enrichment Analysis reveals that Tifab deletion downregulates MYC, HOXA9/MEIS1, mTORC1 signaling, and genes involved in glycolysis and oxidative phosphorylation (OXPHOS). By comparing genes upregulated in TIFAB-overexpressing LSPCs with those downregulated upon Tifab deletion, we identify hepatocyte nuclear factor 4alpha (Hnf4a) as a key TIFAB target, regulated through the inhibition of NF-kB component RelB, which suppresses Hnf4a in leukemia cells. HNF4A, a nuclear receptor involved in organ development, metabolism, and tumorigenesis, rescues the metabolic defects caused by Tifab deletion and enhances leukemia cell engraftment. Conversely, Hnf4a knockdown attenuates TIFAB-mediated enhancement of LSPC function. These findings highlight the critical role of the TIFAB-HNF4A axis in KMT2A::MLLT3-induced AML and uncover a novel regulator in leukemia biology.

Clusterin Deficiency Promotes Cellular Senescence in Human Astrocytes.

The glycoprotein clusterin (CLU) is involved in cell proliferation and DNA damage repair and is highly expressed in tumor cells. Here, we aimed to investigate the effects of CLU dysregulation on two human astrocytic cell lines: CCF-STTG1 astrocytoma cells and SV-40 immortalized normal human astrocytes. We observed that suppression of CLU expression by RNA interference inhibited cell proliferation, triggered the DNA damage response, and resulted in cellular senescence in both cell types tested. To further investigate the underlying mechanism behind these changes, we measured reactive oxygen species, assessed mitochondrial function, and determined selected markers of the senescence-associated secretory phenotype. Our results suggest that CLU deficiency triggers oxidative stress-mediated cellular senescence associated with pronounced alterations in mitochondrial membrane potential, mitochondrial mass, and expression levels of OXPHOS complex I, II, III and IV, indicating mitochondrial dysfunction. This report shows the important role of CLU in cell cycle maintenance in astrocytes. Based on these data, targeting CLU may serve as a potential therapeutic approach valuable for treating gliomas.

The Mitochondrial Fusion Promoter M1 Mitigates Cigarette Smoke-Induced Airway Inflammation and Oxidative Stress via the PI3K-AKT Signaling Pathway.

This study investigated the efficacy and underlying mechanism of the mitochondrial fusion promoter M1 in mitigating cigarette smoking (CS)-induced airway inflammation and oxidative stress both in vitro and in vivo models. Cigarette smoke extract (CSE)-treated airway epithelial cells (BEAS-2B) and CS-exposed mice were pretreated with M1, followed by the measurement of proinflammatory cytokines, oxidative stress, mitochondrial fusion proteins (MFN2 and OPA1) and fission proteins (DRP1 and MFF). Molecular pathways were elucidated through transcriptomic analysis and Western blotting. M1 pretreatment in CSE-treated cells significantly reduced the release of inflammatory cytokines (interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)-α); reduced malondialdehyde (MDA) and reactive oxygen species (ROS) levels; increased superoxide dismutase (SOD) activity; protected mitochondrial function by increasing the expression of mitochondrial fusion proteins (MFN2 and OPA1) and decreasing the expression of mitochondrial fission proteins (DRP1 and MFF). M1 attenuated CS-induced lung histologic damage and mucus hypersecretion in mice, relieved high oxidative stress and reduced the release of IL-6 and IL-8 in BALF. Similarly, it also protected mitochondrial function by regulating the CS-induced imbalance of mitochondrial dynamic proteins. Transcriptome sequencing and Western blotting showed that M1 inhibited CSE- or CS-induced activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/AKT) signaling pathway. M1 plays a protective role in inflammation, oxidative stress and mitochondrial dynamics dysfunction caused by CS by inhibiting the PI3K-AKT signaling pathway; thus, it has therapeutic potential for the treatment of CS-induced airway disorders.

L-Proline Enhanced Whole Ovary Cryopreservation by Inhibiting Ice Crystal Growth and Reducing Oxidative Stress.

Cryopreservation and transplantation of ovaries are considered to be effective methods for preserving the fertility of female cancer patients. However, ice crystal and oxidative damage occur during the freeze-thaw cycle, significantly reducing the effectiveness of cryopreservation and limiting its clinical application. Thus, new technologies or agents must be explored to enhance ovarian cryopreservation. Recently, l-proline, a natural amino acid, has been proven to have good biocompatibility and can clear reactive oxygen species produced during cryopreservation. Whether l-proline can play a positive role in ovarian cryopreservation has not yet been explored. Here, the effect of l-proline on ovarian cryopreservation was investigated. The oxidative antioxidant system, mitochondrial function, and cell apoptosis and proliferation after thawing were systematically evaluated. Moreover, the ice crystal inhibition of l-proline was examined. Furthermore, the morphology and function of oocytes in ovaries, as well as the state of the ovaries after heterotopic renal capsule transplantation, were evaluated to validate the feasibility and reliability of this study. The above results confirm that l-proline can effectively inhibit ice crystal growth, reduce reactive oxygen species production, and enhance cryopreservation effects at the optimal concentration of 20 mM. Altogether, l-proline can significantly improve the cryopreservation effect of ovaries, which is expected to provide a new perspective for the cryopreservation of female fertility.

Blocking adipocyte YY1 decouples thermogenesis from beneficial metabolism by promoting spermidine production.

The accumulation of mitochondria in thermogenic adipose tissue (i.e., brown and beige fat) increases energy expenditure, which can aid in alleviating obesity and metabolic disorders. However, recent studies have shown that knocking out key proteins required to maintain mitochondrial function inhibits the energy expenditure in thermogenic fat, and yet the knockout mice are unexpectedly protected from developing obesity or metabolic disorders when fed a high-fat diet (HFD). In the present study, non-biased sequencing-based screening revealed the importance of YY1 in the transcription of electron transport chain genes and the enhancement of mitochondrial function in thermogenic adipose tissue. Specifically, adipocyte YY1 null (YAKO) mice showed lower energy expenditure and were intolerant to cold stress. Interestingly, YAKO mice showed alleviation of HFD-induced metabolic disorders, which can be attributed to a suppression of adipose tissue inflammation. Metabolomic analysis revealed that blocking YY1 directed glucose metabolism toward lactate, enhanced the uptake of glutamine, and promoted the production of anti-inflammatory spermidine. Conversely, blocking spermidine production in YAKO mice reversed their resistance to HFD-induced disorders. Thus, although blocking adipocyte YY1 impairs the thermogenesis, it promotes spermidine production and alleviates adipose tissue inflammation, therefore leads to an uncoupling of adipose tissue energy expenditure from HFD-induced metabolic disorders.

The dichotomic role of cytokines in aging.

The chronic inflammation present in aged individuals is generally depicted as a detrimental player for longevity. Here, it is discussed several beneficial effects associated with the cytokines that are chronically elevated in inflammaging. These cytokines, such as IL-1β, type I interferons, IL-6 and TNF positively regulate macroautophagy, mitochondrial function, anti-tumor immune responses and skeletal muscle biogenesis, possibly contributing to longevity. On the other side, the detrimental and antagonistic role of these cytokines including the induction of sarcopenia, tissue damage and promotion of tumorigenesis are also discussed, underscoring the dichotomy associated with inflammaging and its players. In addition, it is discussed the role of the anti-inflammatory cytokine IL-10 and other cytokines that affect aging in a more linear way, such as IL-11, which promotes senescence, and IL-4 and IL-15, which promotes longevity. It is also discussed more specific regulators of aging that are downstream cytokines-mediated signaling.

Silver Nanoparticles Reduce ACE2 Expression via Changing Mitochondrial Function in Human Fibroblast-Like Lung Cell and Periodontal Ligament Fibroblast Cells

Silver nanoparticles (AgNPs) have demonstrated antibacterial properties and are widely recognized as one of the most prominent types of nanoparticles. Recent studies have highlighted their effectiveness against coronaviruses. However, the detailed molecular mechanisms underlying the action of AgNPs on viruses and their impacts on the human body remain to be fully elucidated. Thus, we attempt to delineate the preventive effects of AgNPs against SARS-CoV-2 infection. Our findings indicate that treatment with AgNPs reduces ACE2 expression, a key receptor for SARS-CoV-2 particularly in normal oral and lung cells. Additionally, we observed a decrease in the binding affinity of the spike protein to the cell after the AgNP treatment. Through western blot analysis, we identified the involvement of the AKT and/or mTOR signaling pathway in this process. Because AKT and mTOR signaling affects mitochondrial function, we investigated the effects of the AgNP treatment on mitochondria. As a result, we observed the localization of AgNPs within mitochondria. Further, an increase in mitochondrial Fe2+ and reactive oxygen species levels was observed, ultimately resulting in mitochondrial dysfunction. Our results show the efficacy of the AgNP treatment in preventing coronavirus infections.

Protective Effects of Antcin H Isolated from Antrodia cinnamomea Against Neuroinflammation in Huntington's Disease via NLRP3 Inflammasome Inhibition.

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by the expansion of a CAG trinucleotide repeat in the huntingtin (HTT) gene. When the CAG repeat exceeds 36, it results in the accumulation of the mutant HTT (mHTT) protein in neurons and glial cells. Key pathological mechanisms in HD include excitotoxicity, energy dysfunction, impaired mitochondrial function, increased oxidative stress, and neuroinflammation. The NLRP3 inflammasome is a multimeric protein complex element of NLRP3, ASC, and caspase-1, which regulates interleukin (IL)-1β and IL-18 secretion. The NLRP3 inflammasome plays an important role in inflammatory reactions and is involved in the pathogenesis of several neurodegenerative diseases. We have previously demonstrated high NLRP3 inflammasome expression levels in the striatum of R6/2 mice (a transgenic HD mouse model). Systematic administration of an NLRP3 inhibitor (MCC950) to R6/2 mice suppressed the NLRP3 inflammasome, decreased IL-1β and reactive oxygen species production, and reduced neuronal toxicity, suggesting protective effects against HD. Antrodia cinnamomea is an indigenous medicinal fungus in Taiwan, which shows diverse medicinal and pharmacological activities, but its effects in HD are not well understood. Herein, we report that systematic administration of Antcin-H isolated from A. cinnamomea to R6/2 mice suppressed the NLRP3 inflammasome, IL-1β production, and reduced neuronal toxicity. Most importantly, oral administration of Antcin-H reduced disease progression by increasing neuronal survival, reducing neuroinflammation during an extended lifespan, and improving motor dysfunction in R6/2 mice. Taken together, our data suggest that Antcin-H has therapeutic potential for treating HD.

Skeletal Muscle mRNA Splicing Variants Association With Four Different Fitness and Energetic Measures in the GESTALT Study

ABSTRACTBackgroundPhysical activity is essential for maintaining muscle mitochondrial function and aerobic capacity. The molecular mechanisms underlying such protective effects are incompletely understood, in part because it is difficult to separate the effects of disease status and physical activity. We explored the association of human skeletal muscle transcriptomic with four measures of energetics and mitochondria oxidative capacity in healthy individuals.MethodsUsing RNA sequencing of vastus lateralis muscle biopsies from 82 GESTALT participants (52 males, aged 22–89 years), we explored gene and splicing variant expression profiles associated with self‐reported physical activity, peak oxygen consumption (VO2 peak), muscle oxidative capacity (kPCr) and mitochondrial respiration (Mit‐O2 flux). The effect of aging on gene expression was examined in participants with low and high VO2 peak.ResultsThe four measures of energetics were negative correlated with age and generally intercorrelated. We identified protein‐coding genes associated with four energetic measures adjusting for age, muscle fiber‐ratio, sex and batch effect. Mitochondrial pathways were overrepresented across all energetic variables, albeit with little overlap at the gene level. Alternative spliced transcript isoforms associated with energetics were primarily enriched for cytoplasmic ribonucleoprotein granules. The splicing pathway was up‐regulated with aging in low but not in high fitness participants, and transcript isoforms detected in the low fitness group pertain to processes such as cell cycle regulation, RNA/protein localization, nuclear transport and catabolism.ConclusionsA consistent mitochondrial signature emerged across all energetic measures. Alternative splicing was enhanced in older, low fitness participants supporting the energy‐splicing axis hypothesis. The identified splicing variants were enriched in pathways involving the accumulation of ribonucleoproteins in cytoplasmic granules, whose function remains unclear. Further research is needed to understand the function of these proteoforms in promoting adaptation to low energy availability.

CX43-mediated mitochondrial transfer maintains stemness of KG-1a leukemia stem cells through metabolic remodeling

BackgroundAcute myeloid leukemia (AML) is characterized by abundant immature myeloid cells, relapse and refractory due to leukemia stem cells (LSCs). Bone marrow mesenchymal stem/ stromal cells (BMSCs) supported LSCs survival, meanwhile, chemotherapy improved connexin43 (CX43) expression. CX43, as the most intercellular gap junction, facilitated transmit mitochondria from BMSCs into AML. We hypothesized that increased mitochondria transferred from BMSCs supported metabolic remodeling in LSCs to sustain their stemness.MethodsPrimary BMSCs from AML patients were isolated. CX43-BMSCs, overexpressing CX43, were cocultured with KG-1a cells. Fluorescence and confocal microscopy observed mitochondrial transfer. Flow cytometry, EdU assay, and clonogenicity evaluated cell cycle, proliferation, and clonogenic potential. Xenograft mouse models were used to evaluate the tumorigenicity of KG-1a in vivo. Seahorse, RNA-seq, and LC-MS assessed mitochondrial function, transcriptomes, and metabolites post-coculture.ResultsCX43-BMSCs promoted unidirectional mitochondrial transfer, enhancing KG-1a adhesion and proliferation to maintain LSCs stemness in vitro and vivo. RNA-seq revealed coculture with CX43-BMSCs upregulated genes related to adhesion, proliferation, and migration in KG-1a cells. Elevated CX43 expression strengthened BMSCs-KG-1a interaction, facilitating mitochondrial transfer and nucleoside metabolism, fueling KG-1a cells. This enhanced mitochondrial energy metabolism, promoting metabolic reprogramming and clonogenicity.ConclusionCX43-mediated mitochondrial transfer from BMSCs to KG-1a enhances LSCs adhesion, proliferation, clonogenicity, and metabolic reprogramming. CX43 emerges as a potential therapeutic target for AML by sustaining LSCs stemness through metabolic remodeling.

Ginsenoside Rb1 affects mitochondrial Ca2+ transport and inhibits fat deposition and fibrosis by regulating the wnt signaling pathway to treat rotator cuff tears via docking with SFRP1

BackgroundRotator cuff tears (RCTs) are among the most common musculoskeletal disorders that affect quality of life. This study aimed to investigate the efficacy of ginsenoside Rb1 in RCTs and the mechanisms involved.MethodsFirst, a fibrotic model of FAPs was induced, and FAPs were cultured in media supplemented with different concentrations of ginsenoside Rb1. Next, a rat model of RCTs was constructed and treated with ginsenoside Rb1. Molecular docking was subsequently utilized to detect the binding of ginsenoside Rb1 and SFRP1. Finally, SFRP1 was knocked down and overexpressed in vivo and in vitro to investigate the mechanism of ginsenoside Rb1 and SFRP1 in RCTs.ResultsCompared with the Normal group, FAP viability was decreased, but Collagen II, FN and α-SMA levels were increased in the Control group. After treatment with different concentrations of ginsenoside Rb1, FAP viability increased, but Collagen II, FN and α-SMA levels decreased. Among them, 60 µM ginsenoside Rb1 had the best effect. In vivo experiments revealed that ginsenoside Rb1 improved RCTs in rats. Molecular docking revealed the binding of ginsenoside Rb1 to SFRP1. Additionally, SFRP1 levels were lower in the Control group than in the Normal group. After treatment with ginsenoside Rb1, SFRP1 levels increased. In vivo, overexpressing SFRP1 along with ginsenoside Rb1 treatment further alleviated tendon tissue fibroblast infiltration and fat accumulation and further reduced the expression of Collagen II, FN, and α-SMA. In vitro, overexpressing SFRP1 along with ginsenoside Rb1 treatment further decreased the expression of CaMKII, PLC, PKC, Wnt, and β-catenin, further decreased the Ca2+ fluorescence intensity and mitochondrial length, increased the red/green intensity, and decreased the MitoSOX fluorescence intensity. Additionally, overexpressing SFRP1 along with ginsenoside Rb1 treatment further increased cell proliferation, decreased apoptosis, reduced the protein expression of Collagen II, FN, and α-SMA in muscle tissue, and further reduced the levels of TNF-α, IL-1β, and IL-6 in the cell supernatant.ConclusionsGinsenoside Rb1 inhibited the activation of the Wnt signaling pathway by promoting SFRP1 expression, thereby inhibiting mitochondrial function and Ca2+ absorption to treat fat infiltration and muscle fibrosis caused by RCTs.