RESUMEN

Lidamycin (LDM) has been confirmed to have a strong anti-pancreatic cancer effect and can affect the mitochondrial function of pancreatic cancer cells. Mitofusin-2 (Mfn2) is located in the outer membrane of mitochondria, and Mfn2 is currently believed to play a role in cancer inhibition in pancreatic cancer. In order to explore whether the anti-pancreatic cancer effect of LDM is related to Mfn2-mediated mitophagy, Bioinformatics and in vitro cell experiments are used for experimental research. The experimental results demonstrated that Mfn2 is correlated with mitochondrial autophagy in pancreatic cancer. Lidamycin can increase the expression of Mfn2 in pancreatic cancer and affect the process of EMT, affect the level of reactive oxygen species and mitochondrial membrane potential, and increase the expression of mitochondrial autophagy marker proteins BNIP3L and Beclin1. These results demonstrate that Mfn2 affects mitophagy in pancreatic cancer cells by regulating the expression of Mfn2.

Asunto(s)

GTP Fosfohidrolasas , Proteínas de la Membrana , Proteínas Mitocondriales , Mitofagia , Neoplasias Pancreáticas , Humanos , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patología , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/genética , Mitofagia/efectos de los fármacos , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , Línea Celular Tumoral , Proteínas Mitocondriales/metabolismo , Proteínas Mitocondriales/genética , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Aminoglicósidos/farmacología , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Mitocondrias/metabolismo , Mitocondrias/efectos de los fármacos , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Beclina-1/metabolismo , Beclina-1/genética , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Supresoras de Tumor

RESUMEN

Irreversible cardiotoxicity limits the clinical application of doxorubicin (DOX). DOX-induced cardiotoxicity has been associated with induction of senescence and activation of the p38 MAPK pathway. Losmapimod (LOSM), an orally active p38 MAPK inhibitor, is an anti-inflammatory agent with cardioprotective effects. Nevertheless, the effect of LOSM against DOX-induced cardiotoxicity has not been reported. In this study, we determined the effects of LOSM on DOX-induced chronic cardiotoxicity in C57BL/6 N mice. Five-week-old C57BL/6 N mice were fed diet containing LOSM (estimated daily intake 12 mg/kg/day) or a control diet for four days. Thereafter, mice were randomized to receive six weekly intraperitoneal injections of either DOX (4 mg/kg) or saline. Three days after the last injection, cardiac function was assessed by trans-thoracic echocardiography. Activation of p38, JNK, and ERK1/2 MAPKs were assessed by immunoblotting in the heart and liver. Gene expressions of senescence, inflammatory, oxidative stress, and mitochondrial function markers were quantified using real-time PCR and serum inflammatory markers were assessed by Luminex. Our results demonstrated that LOSM attenuated p38 MAPK activation, ameliorated DOX-induced cardiac dysfunction, and abrogated DOX-induced expression of the senescence marker p21Cip1. Additionally, LOSM demonstrated anti-inflammatory effects, with reduced cardiac Il-1α and Il-6 gene expression in DOX-treated mice. Systemic inflammation, assessed by serum cytokine levels, showed decreased IL-6 and CXCL1 in both DOX-treated mice and mice on LOSM diet. LOSM significantly increased mitofusin2 gene expression, which may enhance mitochondrial fusion. These findings underscore the potential therapeutic efficacy of p38 MAPK inhibition, exemplified by LOSM, in ameliorating DOX-induced cardiotoxicity, senescence, and inflammation.

RESUMEN

Background: Neural cell damage is an important cause of exacerbation of depression symptoms caused by hypoxia, but the mechanism behind it is still unclear. The purpose of this study is to elucidate the role of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α)/mitofusin-2 (MFN2) signaling axis in the development of depression in mice under hypoxia. Methods: Male Institute of Cancer Research mice (age, 6 weeks) were assigned to the normal group, chronic unpredictable mild stress group (CUMS group), or CUMS + hyper-hypoxia group (CUMS + H group). Mice in the CUMS and CUMS + H groups were exposed to CUMS for 28 days. Additionally, mice in the CUMS + H group were exposed to acute hyper-hypoxia from Day 21 for 7 days. After a total of 28 days, behavioral experiments were conducted. All mice were anesthetized and sacrificed. Levels of brain tissue interleukin (IL)-6, reactive oxygen species (ROS), adenosine triphosphate (ATP), and serotonin (5-HT) were analyzed. Results: As compared to the CUMS group, mice in the CUMS + H group had increased IL-6 and ROS levels, but lower open-field activity, preference for sucrose, hippocampal neuronal membrane potential, ATP, and 5-HT levels, as well as MFN2 and PGC1α levels. Conclusions: Acute hyper-hypoxia plays an important role in the development of depression via the IL-6/PGC1α/MFN2 signaling pathway.

RESUMEN

In multicellular tissues, the size and shape of cells are intricately linked with their physiological functions. In the vertebrate auditory organ, the neurosensory epithelium develops as a mosaic of sensory hair cells (HCs), and their glial-like supporting cells, which have distinct morphologies and functional properties at different frequency positions along its tonotopic long axis. In the chick cochlea, the basilar papilla (BP), proximal (high-frequency) HCs, are larger than their distal (low-frequency) counterparts, a morphological feature essential for sound perception. Mitochondrial dynamics, which constitute the equilibrium between fusion and fission, regulate differentiation and functional refinement across a variety of cell types. We investigate this as a potential mechanism for regulating the shape of developing HCs. Using live imaging in intact BP explants, we identify distinct remodelling of mitochondrial networks in proximal compared with distal HCs. Manipulating mitochondrial dynamics in developing HCs alters their normal morphology along the proximal-distal (tonotopic) axis. Inhibition of the mitochondrial fusion machinery decreased proximal HC surface area, whereas promotion of fusion increased the distal HC surface area. We identify mitochondrial dynamics as a key regulator of HC morphology in developing inner ear epithelia.

Asunto(s)

Cóclea , Células Ciliadas Auditivas , Mitocondrias , Dinámicas Mitocondriales , Animales , Cóclea/embriología , Cóclea/citología , Cóclea/crecimiento & desarrollo , Células Ciliadas Auditivas/citología , Células Ciliadas Auditivas/metabolismo , Mitocondrias/metabolismo , Embrión de Pollo , Forma de la Célula , Pollos , Diferenciación Celular

RESUMEN

Mitofusins (Mfn1 and Mfn2) are the mitochondrial outer-membrane fusion proteins in mammals and belong to the dynamin superfamily of multidomain GTPases. Recent structural studies of truncated variants lacking alpha helical transmembrane domains suggested that Mfns dimerize to promote the approximation and the fusion of the mitochondrial outer membranes upon the hydrolysis of guanine 5'-triphosphate disodium salt (GTP). However, next to the presence of GTP, the fusion activity seems to require multiple regulatory factors that control the dynamics and kinetics of mitochondrial fusion through the formation of Mfn1-Mfn2 heterodimers. Here, we purified and reconstituted the full-length murine Mfn2 protein into giant unilamellar vesicles (GUVs) with different lipid compositions. The incubation with GTP resulted in the fusion of Mfn2-GUVs. High-speed video-microscopy showed that the Mfn2-dependent membrane fusion pathway progressed through a zipper mechanism where the formation and growth of an adhesion patch eventually led to the formation of a membrane opening at the rim of the septum. The presence of physiological concentration (up to 30 mol%) of dioleoyl-phosphatidylethanolamine (DOPE) was shown to be a requisite to observe GTP-induced Mfn2-dependent fusion. Our observations show that Mfn2 alone can promote the fusion of micron-sized DOPE-enriched vesicles without the requirement of regulatory cofactors, such as membrane curvature, or the assistance of other proteins.

Asunto(s)

GTP Fosfohidrolasas , Fusión de Membrana , Animales , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , Ratones , Fusión de Membrana/fisiología , Liposomas Unilamelares/metabolismo , Liposomas Unilamelares/química , Guanosina Trifosfato/metabolismo , Fosfatidiletanolaminas/metabolismo , Membranas Mitocondriales/metabolismo , Proteínas Mitocondriales/metabolismo , Proteínas Mitocondriales/genética , Mitocondrias/metabolismo

RESUMEN

OBJECTIVE: Mitofusin-2 (MFN2) is a mitochondrial membrane protein that plays a critical role in regulating mitochondrial fusion and cellular metabolism. To further elucidate the impact of MFN2, this study aimed to investigate its significance on hepatocellular carcinoma (HCC) cell function and its potential role in mediating chemosensitivity. METHODS: This study investigated the effects of silencing and overexpressing MFN2 on the survival, proliferation, invasion and migration abilities, and sorafenib resistance of MHCC97-L HCC cells. Additional experiments were conducted using XAV939 (a ß-catenin inhibitor) and HLY78 (a ß-catenin activator) to further validate these findings. RESULTS: Silencing MFN2 significantly promoted the survival and proliferation of MHCC97-L cells, enhanced their invasion and migration capacities, increased the IC50 of sorafenib, reduced the percentage of TUNEL-positive cells, and decreased the expression of proapoptotic proteins. Additionally, silencing MFN2 markedly induced the nuclear translocation of ß-catenin, increased ß-catenin acetylation levels and enhanced the expression of the downstream regulatory proteins Snail1 and Vimentin while inhibiting E-cadherin expression. Conversely, overexpressing MFN2 reversed the effects observed in MHCC97-L cells mentioned above. The results confirmed that silencing MFN2 activated the ß-catenin/epithelial-mesenchymal transition (EMT) pathway and reduced the sensitivity of cells to sorafenib, which could be reversed by XAV939 treatment. Conversely, overexpression of MFN2 inhibited the ß-catenin/EMT pathway and increased the sensitivity of cells to sorafenib, which could be altered by HLY78. CONCLUSION: Low expression of MFN2 in HCC cells promotes the nuclear translocation of ß-catenin, thereby activating the EMT pathway and mediating resistance to sorafenib.

Asunto(s)

Carcinoma Hepatocelular , Movimiento Celular , Proliferación Celular , Resistencia a Antineoplásicos , GTP Fosfohidrolasas , Neoplasias Hepáticas , Sorafenib , Vía de Señalización Wnt , beta Catenina , Humanos , Sorafenib/farmacología , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patología , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Línea Celular Tumoral , beta Catenina/metabolismo , beta Catenina/genética , Vía de Señalización Wnt/efectos de los fármacos , Vía de Señalización Wnt/genética , Proliferación Celular/efectos de los fármacos , Movimiento Celular/efectos de los fármacos , Movimiento Celular/genética , Resistencia a Antineoplásicos/genética , Resistencia a Antineoplásicos/efectos de los fármacos , Silenciador del Gen , Antineoplásicos/farmacología , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Transición Epitelial-Mesenquimal/efectos de los fármacos , Transición Epitelial-Mesenquimal/genética , Apoptosis/efectos de los fármacos , Apoptosis/genética , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos

RESUMEN

Mitochondrial dysfunction and endoplasmic reticulum (ER) stress play pivotal roles in the pathology of cerebral ischemia. In this study, we investigated whether phelligridimer A (PA), an active compound isolated from the medicinal and edible fungus Phellinus igniarius, ameliorates ischemic cerebral injury by restoring mitochondrial function and restricting ER stress. An in vitro cellular model of ischemic stroke-induced neuronal damage was established by exposing HT-22 neuronal cells to oxygen-glucose deprivation/reoxygenation (OGD/R). An in vivo animal model was established in rats subjected to middle cerebral artery occlusion/reperfusion (MCAO/R). The results showed that PA (1-10 µM) dose-dependently increased HT-22 cell viability, reduced OGD/R-induced lactate dehydrogenase release, and reversed OGD/R-induced apoptosis. PA reduced OGD/R-induced accumulation of reactive oxygen species, restored mitochondrial membrane potential, and increased ATP levels. Additionally, PA reduced the expression of the 78-kDa glucose-regulated protein (GRP78) and the phosphorylation of inositol-requiring enzyme-1α (p-IRE1α) and eukaryotic translation-initiation factor 2α (p-eIF2α). PA also inhibited the activation of the mitogen-activated protein kinase (MAPK) pathway in the OGD/R model. Moreover, treatment with PA restored the expression of mitofusin 2 (Mfn-2), a protein linking mitochondria and ER. The silencing of Mfn-2 abolished the protective effects of PA. The results from the animal study showed that PA (3-10 mg/kg) significantly reduced the volume of cerebral infarction and neurological deficits, which were accompanied by an increased level of Mfn-2, and decreased activation of the ER stress in the penumbra of the ipsilateral side after MCAO/R in rats. Taken together, these results indicate that PA counteracts cerebral ischemia-induced injury by restoring mitochondrial function and reducing ER stress. Therefore, PA might be a novel protective agent to prevent ischemia stroke-induced neuronal injury.

Asunto(s)

Isquemia Encefálica , Estrés del Retículo Endoplásmico , GTP Fosfohidrolasas , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno , Daño por Reperfusión , Animales , Masculino , Ratones , Ratas , Apoptosis/efectos de los fármacos , Isquemia Encefálica/metabolismo , Isquemia Encefálica/tratamiento farmacológico , Línea Celular , Supervivencia Celular/efectos de los fármacos , Chaperón BiP del Retículo Endoplásmico/metabolismo , Estrés del Retículo Endoplásmico/efectos de los fármacos , Factor 2 Eucariótico de Iniciación/metabolismo , Glucosa/metabolismo , GTP Fosfohidrolasas/metabolismo , Proteínas de Choque Térmico/metabolismo , Infarto de la Arteria Cerebral Media/metabolismo , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Proteínas Mitocondriales/metabolismo , Proteínas Mitocondriales/genética , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Neuronas/patología , Fármacos Neuroprotectores/farmacología , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Especies Reactivas de Oxígeno/metabolismo , Daño por Reperfusión/metabolismo , Daño por Reperfusión/prevención & control , Daño por Reperfusión/tratamiento farmacológico

RESUMEN

BACKGROUND: Podocyte injury is the most important pathological hallmark of kidney diseases. Autophagy is a critical factor that involves podocyte injury. Here, we sought to determine whether Astragaloside IV (AS-IV) was able to improve renal function and reverse podocyte injury through the regulation of autophagy. METHODS: Using the Adriamycin (ADR) mice model, cultured immortalized mouse podocytes were exposed to AS-IV. Western blotting, immunofluorescence, and histochemistry were used to analyze markers of autophagy, mitochondrial dysfunction, podocyte apoptosis, and glomerulopathy in the progression of focal segmental glomerular sclerosis. RESULTS: We observed that AS-IV can inhibit podocyte apoptosis, increased reactive oxygen species (ROS) generation, mitochondrial fragmentation, and dysfunction by inducing the Mfn2/Pink1/Parkin mitophagy pathway both in vivo and in vitro. Overexpression of Mfn2 reduced puromycin aminonucleoside (PAN)-induced podocyte injury, while downregulation of Mfn2 expression limited the renal protective effect of AS-IV by regulating mitophagy. CONCLUSION: AS-IV ameliorates renal function and renal pathological changes in ADR mice and inhibits PAN-induced podocyte injury by directly enhancing Mfn2/Pink1/Parkin-associated autophagy.

RESUMEN

The heart beats approximately 100,000 times per day in humans, imposing substantial energetic demands on cardiac muscle. Adenosine triphosphate (ATP) is an essential energy source for normal function of cardiac muscle during each beat, as it powers ion transport, intracellular Ca2+ handling, and actin-myosin cross-bridge cycling. Despite this, the impact of excitation-contraction coupling on the intracellular ATP concentration ([ATP]i) in myocytes is poorly understood. Here, we conducted real-time measurements of [ATP]i in ventricular myocytes using a genetically encoded ATP fluorescent reporter. Our data reveal rapid beat-to-beat variations in [ATP]i. Notably, diastolic [ATP]i was <1 mM, which is eightfold to 10-fold lower than previously estimated. Accordingly, ATP-sensitive K+ (KATP) channels were active at physiological [ATP]i. Cells exhibited two distinct types of ATP fluctuations during an action potential: net increases (Mode 1) or decreases (Mode 2) in [ATP]i. Mode 1 [ATP]i increases necessitated Ca2+ entry and release from the sarcoplasmic reticulum (SR) and were associated with increases in mitochondrial Ca2+. By contrast, decreases in mitochondrial Ca2+ accompanied Mode 2 [ATP]i decreases. Down-regulation of the protein mitofusin 2 reduced the magnitude of [ATP]i fluctuations, indicating that SR-mitochondrial coupling plays a crucial role in the dynamic control of ATP levels. Activation of ß-adrenergic receptors decreased [ATP]i, underscoring the energetic impact of this signaling pathway. Finally, our work suggests that cross-bridge cycling is the largest consumer of ATP in a ventricular myocyte during an action potential. These findings provide insights into the energetic demands of EC coupling and highlight the dynamic nature of ATP concentrations in cardiac muscle.

Asunto(s)

Adenosina Trifosfato , Calcio , Acoplamiento Excitación-Contracción , Ventrículos Cardíacos , Miocitos Cardíacos , Miocitos Cardíacos/metabolismo , Adenosina Trifosfato/metabolismo , Acoplamiento Excitación-Contracción/fisiología , Animales , Calcio/metabolismo , Ventrículos Cardíacos/metabolismo , Ventrículos Cardíacos/citología , Potenciales de Acción/fisiología , Retículo Sarcoplasmático/metabolismo , Frecuencia Cardíaca/fisiología , Humanos , Canales KATP/metabolismo , Contracción Miocárdica/fisiología , Ratones

RESUMEN

OBJECTIVE: To evaluate the protective effects of Chang'an decoction (, CAD) on colitis, and investigate the potential mechanisms underlying these effects from the perspectives of endoplasmic reticulum (ER) stress induced by mitofusin 2 (MFN2). METHODS: The composition of CAD was identified by liquid chromatography-mass spectrometry technology. A mice model of dextran sulfate sodium (DSS) induced colitis was established and therapeutic effects of CAD were determined by detecting body weight, disease activity index, colon length and histopathological changes. Then, the expression levels of MFN2, ER stress markers and Nucleotide-binding domain and leucine-rich repeat protein3 (NLRP3) relevant proteins were detected by polymerase chain reaction (PCR), Western blot, immunohistochemistry and immunofluorescence staining. Subsequently, knockdown and overexpression cell model were constructed to further investigate the underlying mechanism of MFN2 mediating ER stress and energy metabolism by PCR, Western blot, electron microscopy and reactive oxygen species (ROS) staining. Finally, inflammatory indicator and tight junction proteins were measured by PCR and immunofluorescence staining to evaluate the protective effects of CAD. RESULTS: Results showed that the indispensable regulatory role of MFN2 in mediating ER stress and mitochondrial damage was involved in the protective effects of CAD on colitis in mice fed with DSS. Network pharmacology analysis also revealed CAD may play a protective effect on colitis by affecting mitochondrial function. In addition, our data also suggested a causative role for MFN2 in the development of inflammatory responses and energy metabolic alterations by constructing a knockdown and overexpression cell model whereby alter proper ER-mitochondria interaction in Caco-2 cells. Furthermore, relative expression analyses of ER stress markers and NLRP3 inflammasome showed the onset of ER stress and activation of NLRP3 inflammasome, which is consistent with the above findings. In contrast, intervention of CAD could improve the mucosal barrier integrity and colonic inflammatory response effectively through inhibiting ER stress response mediated by MFN2. CONCLUSION: CAD could alleviate ER stress by regulating MFN2 to exert therapeutic effects on DSS-induced colitis, which might provide an effective natural therapeutic approach for the treatment of ulcerative colitis.

Asunto(s)

Colitis , Medicamentos Herbarios Chinos , Estrés del Retículo Endoplásmico , GTP Fosfohidrolasas , Animales , Masculino , Ratones , Colitis/tratamiento farmacológico , Colitis/metabolismo , Colitis/genética , Colitis/inducido químicamente , Sulfato de Dextran/efectos adversos , Medicamentos Herbarios Chinos/química , Medicamentos Herbarios Chinos/farmacología , Estrés del Retículo Endoplásmico/efectos de los fármacos , GTP Fosfohidrolasas/efectos de los fármacos , GTP Fosfohidrolasas/metabolismo , Ratones Endogámicos C57BL , Proteínas Mitocondriales/efectos de los fármacos , Proteínas Mitocondriales/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/efectos de los fármacos , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Especies Reactivas de Oxígeno/metabolismo

RESUMEN

Charcot-Marie-Tooth type 2A (CMT2A) is an inherited sensorimotor neuropathy associated with mutations within the Mitofusin 2 (MFN2) gene. These mutations impair normal mitochondrial functioning via different mechanisms, disturbing the equilibrium between mitochondrial fusion and fission, of mitophagy and mitochondrial axonal transport. Although CMT2A disease causes a significant disability, no resolutive treatment for CMT2A patients to date. In this context, reliable experimental models are essential to precisely dissect the molecular mechanisms of disease and to devise effective therapeutic strategies. The most commonly used models are either in vitro or in vivo, and among the latter murine models are by far the most versatile and popular. Here, we critically revised the most relevant literature focused on the experimental models, providing an update on the mammalian models of CMT2A developed to date. We highlighted the different phenotypic, histopathological and molecular characteristics, and their use in translational studies for bringing potential therapies from the bench to the bedside. In addition, we discussed limitations of these models and perspectives for future improvement.

Asunto(s)

Enfermedad de Charcot-Marie-Tooth , Modelos Animales de Enfermedad , Enfermedad de Charcot-Marie-Tooth/genética , Enfermedad de Charcot-Marie-Tooth/patología , Enfermedad de Charcot-Marie-Tooth/terapia , Enfermedad de Charcot-Marie-Tooth/metabolismo , Animales , Humanos , Mutación , Mitocondrias/metabolismo , Mitocondrias/genética , Mitocondrias/patología , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Ratones , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Dinámicas Mitocondriales/genética

RESUMEN

Androgen excess and metabolic abnormality largely contribute to the pathogenesis of polycystic ovarian syndrome (PCOS), which primarily precipitates ovarian dysfunction and infertility in reproductive-age women. Impaired mitochondrial function and epigenetic alteration have been linked to the development of PCOS. However, it is unknown whether acetate would exert a therapeutic effect on ovarian mitochondrial dysfunction in PCOS. Herein, the study hypothesized that acetate reverses ovarian mitochondrial dysfunction in experimental PCOS rat model, possibly through modulation of mitofusin-2 (MFn2). Eight-week-old female Wistar rats were randomized into four groups (n = 5). Induction of PCOS was performed by 1 mg/kg letrozole (p.o.), administered for 21 days. Thereafter, the rats were treated with acetate (200 mg/kg; p.o.) for 6 weeks. The PCOS rats demonstrated androgen excess, multiple ovarian cysts, elevated anti-mullerian hormone and leptin and decreased SHBG, adiponectin and 17-ß estradiol with corresponding increase in ovarian transforming growth factor-ß1. Additionally, inflammation (tumor growth factor and nuclear factor-kB), elevated caspase-6, decreased hypoxia-inducible factor-1α and elevated histone deacetylase-2 (HDAC2) were observed in the ovaries of PCOS rats, while mitochondrial abnormality with evidence of decreased adenosine triphosphate synthase and MFn2 was observed in rats with PCOS. Treatment with acetate reversed the alterations. The present results collectively suggest that acetate ameliorates ovarian mitochondrial abnormality, a beneficial effect that is accompanied by MFn2 with consequent normalization of reproductive-endocrine profile and ovarian function. Perhaps, the present data provide hope for PCOS individuals that suffer infertility.

Asunto(s)

Infertilidad , Enfermedades Mitocondriales , Síndrome del Ovario Poliquístico , Humanos , Femenino , Ratas , Animales , Síndrome del Ovario Poliquístico/inducido químicamente , Síndrome del Ovario Poliquístico/tratamiento farmacológico , Síndrome del Ovario Poliquístico/metabolismo , Letrozol/efectos adversos , Andrógenos/efectos adversos , Ratas Wistar , Infertilidad/complicaciones , Mitocondrias/metabolismo , Acetatos/efectos adversos

RESUMEN

BACKGROUND: Senescent astrocytes play crucial roles in age-associated neurodegenerative diseases, including Parkinson's disease (PD). Metformin, a drug widely used for treating diabetes, exerts longevity effects and neuroprotective activities. However, its effect on astrocyte senescence in PD remains to be defined. METHODS: Long culture-induced replicative senescence model and 1-methyl-4-phenylpyridinium/α-synuclein aggregate-induced premature senescence model, and a mouse model of PD were used to investigate the effect of metformin on astrocyte senescence in vivo and in vitro. Immunofluorescence staining and flow cytometric analyses were performed to evaluate the mitochondrial function. We stereotactically injected AAV carrying GFAP-promoter-cGAS-shRNA to mouse substantia nigra pars compacta regions to specifically reduce astrocytic cGAS expression to clarify the potential molecular mechanism by which metformin inhibited the astrocyte senescence in PD. RESULTS: We showed that metformin inhibited the astrocyte senescence in vitro and in PD mice. Mechanistically, metformin normalized mitochondrial function to reduce mitochondrial DNA release through mitofusin 2 (Mfn2), leading to inactivation of cGAS-STING, which delayed astrocyte senescence and prevented neurodegeneration. Mfn2 overexpression in astrocytes reversed the inhibitory role of metformin in cGAS-STING activation and astrocyte senescence. More importantly, metformin ameliorated dopamine neuron injury and behavioral deficits in mice by reducing the accumulation of senescent astrocytes via inhibition of astrocytic cGAS activation. Deletion of astrocytic cGAS abolished the suppressive effects of metformin on astrocyte senescence and neurodegeneration. CONCLUSIONS: This work reveals that metformin delays astrocyte senescence via inhibiting astrocytic Mfn2-cGAS activation and suggest that metformin is a promising therapeutic agent for age-associated neurodegenerative diseases.

Asunto(s)

Metformina , Enfermedad de Parkinson , Ratones , Animales , Enfermedad de Parkinson/metabolismo , Metformina/farmacología , Metformina/uso terapéutico , Astrocitos/metabolismo , Neuronas Dopaminérgicas , Nucleotidiltransferasas/metabolismo , Mitocondrias/metabolismo , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/farmacología

RESUMEN

Our study aimed to explore the potential positive effects of cold water exercise on mitochondrial biogenesis and muscle energy metabolism in aging rats. The study involved 32 male and 32 female rats aged 15 months, randomly assigned to control sedentary animals, animals training in cold water at 5 ± 2 °C, or animals training in water at thermal comfort temperature (36 ± 2 °C). The rats underwent swimming training for nine weeks, gradually increasing the duration of the sessions from 2 min to 4 min per day, five days a week. The results demonstrated that swimming in thermally comfortable water improved the energy metabolism of aging rat muscles (increased metabolic rates expressed as increased ATP, ADP concentration, TAN (total adenine nucleotide) and AEC (adenylate energy charge value)) and increased mRNA and protein expression of fusion regulatory proteins. Similarly, cold-water swimming improved muscle energy metabolism in aging rats, as shown by an increase in muscle energy metabolites and enhanced mitochondrial biogenesis and dynamics. It can be concluded that the additive effect of daily activity in cold water influenced both an increase in the rate of energy metabolism in the muscles of the studied animals and an intensification of mitochondrial biogenesis and dynamics (related to fusion and fragmentation processes). Daily activity in warm water also resulted in an increase in the rate of energy metabolism in muscles, but at the same time did not cause significant changes in mitochondrial dynamics.

Asunto(s)

Biogénesis de Organelos , Natación , Femenino , Masculino , Animales , Ratas , Músculos , Metabolismo Energético , Envejecimiento , Agua

RESUMEN

Most congenital heart defect (CHD) cases are attributed to nongenetic factors; however, the mechanisms underlying nongenetic factor-induced CHDs are elusive. Maternal diabetes is one of the nongenetic factors, and this study aimed to determine whether impaired mitochondrial fusion contributes to maternal diabetes-induced CHDs and if mitochondrial fusion activators, teriflunomide and echinacoside, could reduce CHD incidence in diabetic pregnancy. We demonstrated maternal diabetes-activated FoxO3a increases miR-140 and miR-195, which in turn represses Mfn1 and Mfn2, leading to mitochondrial fusion defects and CHDs. Two mitochondrial fusion activators are effective in preventing CHDs in diabetic pregnancy.

RESUMEN

Tamoxifen (TAM) resistance presents a major clinical obstacle in the management of estrogen-sensitive breast cancer, highlighting the need to understand the underlying mechanisms and potential therapeutic approaches. We showed that dysregulated mitochondrial dynamics were involved in TAM resistance by protecting against mitochondrial apoptosis. The dysregulated mitochondrial dynamics were associated with increased mitochondrial fusion and decreased fission, thus preventing the release of mitochondrial cytochrome c to the cytoplasm following TAM treatment. Dynamin-related GTPase protein mitofusin 1 (MFN1), which promotes fusion, was upregulated in TAM-resistant cells, and high MFN1 expression indicated a poor prognosis in TAM-treated patients. Mitochondrial translocation of MFN1 and interaction between MFN1 and mitofusin 2 (MFN2) were enhanced to promote mitochondrial outer membrane fusion. The interaction of MFN1 and cristae-shaping protein optic atrophy 1 (OPA1) and OPA1 oligomerization were reduced due to augmented OPA1 proteolytic cleavage, and their apoptosis-promoting function was reduced due to cristae remodeling. Furthermore, the interaction of MFN1 and BAK were increased, which restrained BAK activation following TAM treatment. Knockdown or pharmacological inhibition of MFN1 blocked mitochondrial fusion, restored BAK oligomerization and cytochrome c release, and amplified activation of caspase-3/9, thus sensitizing resistant cells to apoptosis and facilitating the therapeutic effects of TAM both in vivo and in vitro. Conversely, overexpression of MFN1 alleviated TAM-induced mitochondrial apoptosis and promoted TAM resistance in sensitive cells. These results revealed that dysregulated mitochondrial dynamics contributes to the development of TAM resistance, suggesting that targeting MFN1-mediated mitochondrial fusion is a promising strategy to circumvent TAM resistance.

Asunto(s)

Apoptosis , Neoplasias de la Mama , Resistencia a Antineoplásicos , GTP Fosfohidrolasas , Dinámicas Mitocondriales , Tamoxifeno , Humanos , Tamoxifeno/farmacología , Dinámicas Mitocondriales/efectos de los fármacos , Apoptosis/efectos de los fármacos , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Resistencia a Antineoplásicos/efectos de los fármacos , Femenino , Neoplasias de la Mama/patología , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Animales , Ratones , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , Proteínas de Transporte de Membrana Mitocondrial/genética , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Línea Celular Tumoral , Antineoplásicos Hormonales/farmacología , Proteína Destructora del Antagonista Homólogo bcl-2/metabolismo , Proteína Destructora del Antagonista Homólogo bcl-2/genética , Células MCF-7 , Proteínas Mitocondriales/metabolismo , Proteínas Mitocondriales/genética , Ensayos Antitumor por Modelo de Xenoinjerto

RESUMEN

PURPOSE: Diabetic cardiomyopathy is a prevalent cardiovascular complication of diabetes mellitus. This study aimed to investigate the effects of ginsenoside Rb1 (GRb1) on the diabetic myocardium. METHODS: Leptin receptor-deficient db/db mice and palmitic acid (PA)-treated cardiomyocyte models were utilized. Cardiac systolic and diastolic function, mitochondrial morphology, and respiratory chain function were determined. The expression of mitochondrial dynamics proteins was measured. Mitofusin 2 (Mfn2) overexpression and inhibition were achieved by lentiviral infection and small interfering RNA (siRNA) transfection. RESULTS: In comparison to non-diabetic mice, db/db mice exhibited significant increases in body weight, blood glucose, blood lipids, and cardiac free fatty acid levels. This was accompanied by myocardial hypertrophy and left ventricular diastolic dysfunction, which were significantly ameliorated by GRb1 intervention. Stimulation with PA increased oxidative stress and apoptosis, and decreased viability in H9c2 cardiomyocytes. PA also reduced sarcomere contractility and relaxation in adult mice ventricular myocytes. PA-induced cellular and mitochondrial damage were reversed with GRb1 treatment. The cardiac tissue of db/db mice and PA-treated cardiomyocytes exhibited a decrease in Mfn2 expression, which was markedly improved by GRb1. Mfn2 overexpression reversed PA-induced mitochondrial fragmentation and functional damage in cardiomyocytes, while inhibition of Mfn2 expression by siRNA transfection blocked the protective effects of GRb1. CONCLUSION: GRb1 alleviated myocardial lipid accumulation and mitochondrial injury, and attenuated ventricular diastolic dysfunction in diabetic mice. The regulation of Mfn2 was involved in the protective effects of GRb1 against lipotoxic myocardial injury.

Asunto(s)

Cardiomiopatías Diabéticas , GTP Fosfohidrolasas , Ginsenósidos , Miocitos Cardíacos , Animales , Ginsenósidos/farmacología , Ginsenósidos/uso terapéutico , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Cardiomiopatías Diabéticas/metabolismo , Cardiomiopatías Diabéticas/tratamiento farmacológico , Cardiomiopatías Diabéticas/patología , Ratones , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/genética , Masculino , Ácido Palmítico/farmacología , Apoptosis/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/metabolismo , Ratas , Receptores de Leptina/genética , Receptores de Leptina/metabolismo , Receptores de Leptina/deficiencia , Línea Celular , Ratones Endogámicos C57BL , Miocardio/patología , Miocardio/metabolismo

RESUMEN

Mutations in the gene encoding MFN2 have been identified as associated with Charcot-Marie-Tooth disease type 2A (CMT2A), a neurological disorder characterized by a broad clinical phenotype involving the entire nervous system. MFN2, a dynamin-like GTPase protein located on the outer mitochondrial membrane, is well-known for its involvement in mitochondrial fusion. Numerous studies have demonstrated its participation in a network crucial for various other mitochondrial functions, including mitophagy, axonal transport, and its controversial role in endoplasmic reticulum (ER)-mitochondria contacts. Considerable progress has been made in the last three decades in elucidating the disease pathogenesis, aided by the generation of animal and cellular models that have been instrumental in studying disease physiology. A review of the literature reveals that, up to now, no definitive pharmacological treatment for any CMT2A variant has been established; nonetheless, recent years have witnessed substantial progress. Many treatment approaches, especially concerning molecular therapy, such as histone deacetylase inhibitors, peptide therapy to increase mitochondrial fusion, the new therapeutic strategies based on MF1/MF2 balance, and SARM1 inhibitors, are currently in preclinical testing. The literature on gene silencing and gene replacement therapies is still limited, except for a recent study by Rizzo et al.(Rizzo et al., 2023), which recently first achieved encouraging results in in vitro and in vivo models of the disease. The near-future goal for these promising therapies is to progress to the stage of clinical translation.

Asunto(s)

Enfermedad de Charcot-Marie-Tooth , Animales , Enfermedad de Charcot-Marie-Tooth/genética , Enfermedad de Charcot-Marie-Tooth/terapia , Enfermedad de Charcot-Marie-Tooth/metabolismo , Mitocondrias/metabolismo , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , Fenotipo , Proteínas Mitocondriales/metabolismo , Mutación

RESUMEN

Long non-coding RNA FENDRR possesses both anti-fibrotic and anti-cancer properties, but its significance in the development of premalignant oral submucous fibrosis (OSF) remains unclear. Here, we showed that FENDRR was downregulated in OSF specimens and fibrotic buccal mucosal fibroblasts (fBMFs), and overexpression of FENDRR mitigated various myofibroblasts hallmarks, and vice versa. In the course of investigating the mechanism underlying the implication of FENDRR in myofibroblast transdifferentiation, we found that FENDRR can directly bind to miR-214 and exhibit its suppressive effect on myofibroblast activation via titrating miR-214. Moreover, we showed that mitofusin 2 (MFN2), a protein that is crucial to the fusion of mitochondria, was a direct target of miR-214. Our data suggested that FENDRR was positively correlated with MFN2 and MFN2 was required for the inhibitory property of FENDRR pertaining to myofibroblast phenotypes. Additionally, our results showed that the FENDRR/miR-214 axis participated in the arecoline-induced reactive oxygen species (ROS) accumulation and myofibroblast transdifferentiation. Building on these results, we concluded that the aberrant downregulation of FENDRR in OSF may be associated with chronic exposure to arecoline, leading to upregulation of ROS and myofibroblast activation via the miR-214-mediated suppression of MFN2.

Asunto(s)

MicroARNs , Fibrosis de la Submucosa Bucal , Humanos , Miofibroblastos/metabolismo , Arecolina/efectos adversos , Arecolina/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Fibrosis de la Submucosa Bucal/genética , Fibrosis de la Submucosa Bucal/metabolismo , Fibrosis de la Submucosa Bucal/patología , Mucosa Bucal/metabolismo , Fibroblastos , MicroARNs/genética , MicroARNs/metabolismo , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/farmacología , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo

RESUMEN

AIM: Sarcopenia, the aging-related loss of muscle mass and function, is a debilitating process negatively impacting the quality of life of affected individuals. Although the mechanisms underlying sarcopenia are incompletely understood, impairments in mitochondrial dynamics, including mitochondrial fusion, have been proposed as a contributing factor. However, the potential of upregulating mitochondrial fusion proteins to alleviate the effects of aging on skeletal muscles remains unexplored. We therefore hypothesized that overexpressing Mitofusin 2 (MFN2) in skeletal muscle in vivo would mitigate the effects of aging on muscle mass and improve mitochondrial function. METHODS: MFN2 was overexpressed in young (7 mo) and old (24 mo) male mice for 4 months through intramuscular injections of an adeno-associated viruses. The impacts of MFN2 overexpression on muscle mass and fiber size (histology), mitochondrial respiration, and H2O2 emission (Oroboros fluororespirometry), and various signaling pathways (qPCR and western blotting) were investigated. RESULTS: MFN2 overexpression increased muscle mass and fiber size in both young and old mice. No sign of fibrosis, necrosis, or inflammation was found upon MFN2 overexpression, indicating that the hypertrophy triggered by MFN2 overexpression was not pathological. MFN2 overexpression even reduced the proportion of fibers with central nuclei in old muscles. Importantly, MFN2 overexpression had no impact on muscle mitochondrial respiration and H2O2 emission in both young and old mice. MFN2 overexpression attenuated the increase in markers of impaired autophagy in old muscles. CONCLUSION: MFN2 overexpression may be a viable approach to mitigate aging-related muscle atrophy and may have applications for other muscle disorders.