Endoplasmic Reticulum Associated Degradation (ERAD) Deficiency Promotes Mitochondrial Dysfunction and Transcriptional Rewiring in Human Hepatic Cells

AbstractMitochondrial dysfunction has been associated with a variety of human diseases including neurodegeneration, diabetes, non-alcohol fatty liver disease (NAFLD) and cancer, but its underlying causes are incompletely understood. Endoplasmic reticular associated degradation (ERAD) is a protein quality control process essential for maintaining ER homeostasis. Using the human hepatic cell line HepG2 as a model, we show here that ERAD is critically required for mitochondrial function in mammalian cells. Pharmacological inhibition or genetic ablation of ERAD increases cell death under both basal conditions and in response to proinflammatory cytokines. Decreased viability of ERAD-deficient HepG2 cells was traced to impaired mitochondrial functions including reduced ATP production, enhanced reactive oxygen species (ROS) accumulation and increased mitochondrial outer membrane permeability (MOMP). Transcriptome profiling reveals widespread down-regulation in the expression of genes underpinning mitochondrial functions, and up-regulation in the genes with association to tumor growth and aggression. These results highlight a critical role for ERAD in maintaining mitochondrial functional and structural integrity and raise the possibility to improve cellular and organismal mitochondrial function via enhancing cellular ERAD capacity.

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ERAD deficiency promotes mitochondrial dysfunction and transcriptional rewiring in human hepatic cells

Journal of Biological Chemistry ◽

10.1074/jbc.ra120.013987 ◽

2020 ◽

Vol 295 (49) ◽

pp. 16743-16753

Author(s):

Qingqing Liu ◽

Xiaoqin Yang ◽

Guangyu Long ◽

Yabing Hu ◽

Zhenglong Gu ◽

...

Keyword(s):

Mitochondrial Dysfunction ◽

Mitochondrial Function ◽

Mammalian Cells ◽

Structural Integrity ◽

Protein Quality ◽

Critical Role ◽

Mitochondrial Outer Membrane ◽

Genetic Ablation ◽

Mitochondrial Functions ◽

Quality Control Process

Mitochondrial dysfunction is associated with a variety of human diseases including neurodegeneration, diabetes, nonalcohol fatty liver disease (NAFLD), and cancer, but its underlying causes are incompletely understood. Using the human hepatic cell line HepG2 as a model, we show here that endoplasmic reticulum-associated degradation (ERAD), an ER protein quality control process, is critically required for mitochondrial function in mammalian cells. Pharmacological inhibition or genetic ablation of key proteins involved in ERAD increased cell death under both basal conditions and in response to proinflammatory cytokines, a situation frequently found in NAFLD. Decreased viability of ERAD-deficient HepG2 cells was traced to impaired mitochondrial functions including reduced ATP production, enhanced reactive oxygen species (ROS) accumulation, and increased mitochondrial outer membrane permeability. Transcriptome profiling revealed widespread down-regulation of genes underpinning mitochondrial functions, and up-regulation of genes associated with tumor growth and aggression. These results highlight a critical role for ERAD in maintaining mitochondrial functional and structural integrity and raise the possibility of improving cellular and organismal mitochondrial function via enhancing cellular ERAD capacity.

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Primary and Secondary Drug Screening Assays for Friedreich Ataxia

CrossRef Listing of Deleted DOIs ◽

10.1177/1087057111427949 ◽

2011 ◽

Vol 17 (3) ◽

pp. 303-313 ◽

Cited By ~ 14

Author(s):

M. Grazia Cotticelli ◽

Lynn Rasmussen ◽

Nicole L. Kushner ◽

Sara McKellip ◽

Melinda Ingrum Sosa ◽

...

Keyword(s):

Mitochondrial Dysfunction ◽

Mitochondrial Function ◽

High Throughput Screening ◽

Mammalian Cells ◽

Friedreich Ataxia ◽

Krebs Cycle ◽

C2c12 Cells ◽

Transport Chain ◽

Screening Assays ◽

Yeast Mutants

Friedreich ataxia (FRDA) is an autosomal recessive neuro- and cardiodegenerative disorder for which there are no proven effective treatments. FRDA is caused by decreased expression and/or function of the protein frataxin. Frataxin chaperones iron in the mitochondrial matrix for the assembly of iron–sulfur clusters (ISCs), which are prosthetic groups critical for the function of the Krebs cycle and the mitochondrial electron transport chain (ETC). Decreased expression of frataxin or the yeast frataxin orthologue, Yfh1p, is associated with decreased ISC assembly, mitochondrial iron accumulation, and increased oxidative stress, all of which contribute to mitochondrial dysfunction. Using yeast depleted of Yfh1p, a high-throughput screening (HTS) assay was developed in which mitochondrial function was monitored by reduction of the tetrazolium dye WST-1 in a growth medium with a respiration-only carbon source. Of 101 200 compounds screened, 302 were identified that effectively rescue mitochondrial function. To confirm activities in mammalian cells and begin understanding mechanisms of action, secondary screening assays were developed using murine C2C12 cells and yeast mutants lacking specific complexes of the ETC, respectively. The compounds identified in this study have potential relevance for other neurodegenerative disorders associated with mitochondrial dysfunction, such as Parkinson disease.

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Snapin deficiency is associated with developmental defects of the central nervous system

Bioscience Reports ◽

10.1042/bsr20100110 ◽

2010 ◽

Vol 31 (2) ◽

pp. 151-158 ◽

Cited By ~ 8

Author(s):

Bing Zhou ◽

Yi-Bing Zhu ◽

Lin Lin ◽

Qian Cai ◽

Zu-Hang Sheng

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Protein Quality ◽

Third Ventricle ◽

Critical Role ◽

Developmental Defects ◽

Lysosomal Function ◽

Quality Control Process ◽

The Central Nervous System

The autophagy–lysosomal pathway is an intracellular degradation process essential for maintaining neuronal homoeostasis. Defects in this pathway have been directly linked to a growing number of neurodegenerative disorders. We recently revealed that Snapin plays a critical role in co-ordinating dynein-driven retrograde transport and late endosomal–lysosomal trafficking, thus maintaining efficient autophagy–lysosomal function. Deleting snapin in neurons impairs lysosomal proteolysis and reduces the clearance of autolysosomes. The role of the autophagy–lysosomal system in neuronal development is, however, largely uncharacterized. Here, we report that snapin deficiency leads to developmental defects in the central nervous system. Embryonic snapin−/− mouse brain showed reduced cortical plates and intermediate zone cell density, increased apoptotic death in the cortex and third ventricle, enhanced membrane-bound LC3-II staining associated with autophagic vacuoles and an accumulation of polyubiquitinated proteins in the cortex and hippocampus. Thus our results provide in vivo evidence for the essential role of late endocytic transport and autophagy–lysosomal function in maintaining neuronal survival and development of the mammalian central nervous system. In addition, our study supports the existence of a functional interplay between the autophagy–lysosome and ubiquitin–proteasome systems in the protein quality-control process.

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Garlic extract attenuates brain mitochondrial dysfunction and cognitive deficit in obese-insulin resistant rats

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2014-0255 ◽

2014 ◽

Vol 39 (12) ◽

pp. 1373-1379 ◽

Cited By ~ 18

Author(s):

Hiranya Pintana ◽

Jirapas Sripetchwandee ◽

Luerat Supakul ◽

Nattayaporn Apaijai ◽

Nipon Chattipakorn ◽

...

Keyword(s):

Body Weight ◽

Cognitive Function ◽

Mitochondrial Dysfunction ◽

Mitochondrial Function ◽

Visceral Fat ◽

Cognitive Deficit ◽

Garlic Extract ◽

Insulin Resistant ◽

Mitochondrial Functions ◽

Brain Mitochondrial Function

Oxidative stress in the obese-insulin resistant condition has been shown to affect cognitive as well as brain mitochondrial functions. Garlic extract has exerted a potent antioxidant effect. However, the effects of garlic extract on the brain of obese-insulin resistant rats have never been investigated. We hypothesized that garlic extract improves cognitive function and brain mitochondrial function in obese-insulin resistant rats induced by long-term high-fat diet (HFD) consumption. Male Wistar rats were fed either normal diet or HFD for 16 weeks (n = 24/group). At week 12, rats in each dietary group received either vehicle or garlic extract (250 and 500 mg·kg–1·day–1) for 28 days. Learning and memory behaviors, metabolic parameters, and brain mitochondrial function were determined at the end of treatment. HFD led to increased body weight, visceral fat, plasma insulin, cholesterol, and malondialdehyde (MDA) levels, indicating the development of insulin resistance. Furthermore, HFD rats had cognitive deficit and brain mitochondrial dysfunction. HFD rats treated with both doses of garlic extract had decreased body weight, visceral fat, plasma cholesterol, and MDA levels. Garlic extract also improved cognitive function and brain mitochondrial function, which were impaired in obese-insulin resistant rats caused by HFD consumption.

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Zhen-Wu-Tang Induced Mitophagy to Protect Mitochondrial Function in Chronic Glomerulonephritis via PI3K/AKT/mTOR and AMPK Pathways

Frontiers in Pharmacology ◽

10.3389/fphar.2021.777670 ◽

2021 ◽

Vol 12 ◽

Author(s):

Bihao Liu ◽

Yiwen Cao ◽

Dejuan Wang ◽

Yuan Zhou ◽

Peichun Zhang ◽

...

Keyword(s):

Mitochondrial Dysfunction ◽

Mitochondrial Function ◽

Mitochondrial Membrane ◽

Periodic Acid ◽

Underlying Mechanism ◽

Chronic Glomerulonephritis ◽

Heat Shock Protein 60 ◽

Periodic Acid Schiff ◽

Pi3k Inhibitor Ly294002 ◽

Mitochondrial Functions

Chronic glomerulonephritis (CGN) is one of the major causes of end-stage kidney disease. Zhen-wu-tang (ZWT), as a famous Chinese herbal prescription, is widely used in China for CGN therapy in clinic. However, the mechanism of ZWT in CGN has not been fully understood. The present study explored the therapeutic effect and the underlying mechanism of ZWT on mitochondrial function in cationic bovine serum albumin (C-BSA)-induced CGN model rats and tumor necrosis factor (TNF-α)-damaged mouse podocytes. The renal functions were measured by serum creatinine (Scr) and blood urea nitrogen (BUN). Renal pathological changes and ultrastructure of kidney tissues were evaluated by periodic acid-Schiff (PAS) staining and transmission electron microscopy. The levels of antioxidases, including mitochondrial catalase (CAT), superoxide dismutase 2 (SOD2), and peroxiredoxin 3 (PRDX3), in CGN rats were examined by real-time PCR. The mitochondrial functions of podocytes were measured by ATP concentration, mitochondrial membrane potential (MMP), and mitochondrial ROS (mtROS). For mitophagy level detection, the expressions of mitophagy-related proteins, including LC3, p62, heat shock protein 60 (HSP60), and translocase of outer mitochondrial membrane 20 (TOMM20), were measured by Western blot, as the colocation of LC3 and mitochondrial marker COX IV were evaluated by immunofluorescence. Our results manifested that ZWT ameliorated CGN model rats by a remarkable decrease in Scr and BUN, inhibition of mesangial matrix proliferation, protection against foot processes fusion, and basement membrane thickening. More importantly, ZWT protected against mitochondrial dysfunction by increasing the expressions of CAT, SOD2, and PRDX3 in CGN model rats, increased ATP content and MMP in podocytes, and decreased excessive mtROS. Furthermore, ZWT induced mitophagy in CGN through increasing the expression of LC3, and decreasing p62, HSP60, TOMM20, and ZWT also enhanced the colocation of LC3 to the mitochondria. We found that ZWT inhibited the PI3K/AKT/mTOR pathway, which could be disturbed by PI3K inhibitor LY294002 and agonist insulin-like growth factor 1. Moreover, ZWT reversed the inhibition of the AMPK pathway in CGN. Overall, ZWT ameliorated renal mitochondrial dysfunction probably by inducing mitophagy via the PI3K/AKT/mTOR and AMPK pathways.

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Abstract P005: Mitochondrial Dysfunction in Heart of Coronary Artery Disease: Correlation with Telomerase Activity

Hypertension ◽

10.1161/hyp.66.suppl_1.p005 ◽

2015 ◽

Vol 66 (suppl_1) ◽

Author(s):

Karima Ait-Aissa ◽

Joohwan Kim ◽

Garrett Morgan ◽

Janine H Santos ◽

Amadou K Camara ◽

...

Keyword(s):

Coronary Artery Disease ◽

Coronary Artery ◽

Mitochondrial Dysfunction ◽

Mitochondrial Function ◽

Critical Role ◽

Telomerase Activity ◽

Dominant Negative ◽

Pcr Analysis ◽

Tissue Samples ◽

Artery Disease

Rational: Heart disease is the leading cause of death worldwide and abnormalities in mitochondrial function are increasingly recognized in association with cardiomyopathy, heart failure, endothelial dysfunction and coronary artery disease (CAD). However the direct contribution and mechanism of the mitochondrial dysfunction on the development of CAD is not fully determined. We have recently shown a critical role of TERT, the catalytic subunit of telomerase, as a regulator of mitochondrial integrity in the microcirculation. We observed increased expression of the dominant negative splice variant of TERT ( β -del) in the Left Ventricle from subjects with CAD. Therefore, we hypothesize that TERT ( β -del) decreases mitochondrial telomerase activity in the human heart resulting in mitochondrial damage that contributes to an environment that promotes the development of CAD . Methods: Fresh and frozen tissue samples of discarded heart tissue from subjects with and without CAD were used. Protein, cell lysate or mitochondria were isolated using standard techniques. Mitochondrial DNA, levels of NAD+ and ATP as well as mitochondrial oxidative phosphorylation were evaluated. Results: PCR analysis revealed an increased frequency of mitochondrial common deletion, an established marker for mitochondrial abnormalities (0.9±0.2 in CAD; vs 1.5±0.2 in non-CAD; N=8; P<0.05). NAD+ and ATP levels were significantly decreased in CAD subjects compared to non-CAD (291±62 and 0.5±0.1 RLU/mg protein in CAD vs. 4203±336 and 84.1±24.8 pmol/mg protein in non-CAD respectively; N=15; P<0.005). Decrease respiration control index (RCI) in the presence of either complex I substrate K (+)-pyruvate/malate (PM) or complex II substrate K (+)-succinate (SUC) was observed in tissue form subjects with CAD (KPM-RCI: 2.9±1.3; SUC-RCI: 7.6± 1.9 in CAD vs KPM-RCI: 8.5±1.9; SUC-RCI: 19.1± 8.3 in non-CAD; N=3; P<0.05) Conclusions: Together these results point to significantly impaired mitochondrial function in subjects with CAD that are associated with decreased in mitochondrial telomerase activity.

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Mitochondrial Function and Mitophagy in the Elderly: Effects of Exercise

Oxidative Medicine and Cellular Longevity ◽

10.1155/2017/2012798 ◽

2017 ◽

Vol 2017 ◽

pp. 1-13 ◽

Cited By ~ 35

Author(s):

Osvaldo C. Moreira ◽

Brisamar Estébanez ◽

Susana Martínez-Florez ◽

José A. de Paz ◽

María J. Cuevas ◽

...

Keyword(s):

Mitochondrial Function ◽

Structural Integrity ◽

Apoptotic Cell ◽

The Elderly ◽

Model Organisms ◽

Beneficial Effects ◽

Cell Life ◽

Mitochondrial Functions ◽

Quantity Control ◽

Changes Over Time

Aging is a natural, multifactorial and multiorganic phenomenon wherein there are gradual physiological and pathological changes over time. Aging has been associated with a decrease of autophagy capacity and mitochondrial functions, such as biogenesis, dynamics, and mitophagy. These processes are essential for the maintenance of mitochondrial structural integrity and, therefore, for cell life, since mitochondrial dysfunction leads to an impairment of energy metabolism and increased production of reactive oxygen species, which consequently trigger mechanisms of cellular senescence and apoptotic cell death. Moreover, reduced mitochondrial function can contribute to age-associated disease phenotypes in model organisms and humans. Literature data show beneficial effects of exercise on the impairment of mitochondrial biogenesis and dynamics and on the decrease in the mitophagic capacity associated to aging. Thus, exercise could have effects on the major cell signaling pathways that are involved in the mitochondria quality and quantity control in the elderly. Although it is known that several exercise protocols are able to modify the activity and turnover of mitochondria, further studies are necessary in order to better identify the mechanisms of interaction between mitochondrial functions, aging, and physical activity, as well as to analyze possible factors influencing these processes.

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The Use of Chinese Yang/Qi-Invigorating Tonic Botanical Drugs/Herbal Formulations in Ameliorating Chronic Kidney Disease by Enhancing Mitochondrial Function

Frontiers in Pharmacology ◽

10.3389/fphar.2021.622498 ◽

2021 ◽

Vol 12 ◽

Author(s):

Jiayi Tian ◽

Yuqi Huang ◽

Tong Wu ◽

Hsien-Da Huang ◽

Kam Ming Ko ◽

...

Keyword(s):

Chronic Kidney Disease ◽

Kidney Disease ◽

Mitochondrial Function ◽

Antioxidant Status ◽

Molecular Mechanisms ◽

Critical Role ◽

Mitochondrial Energy Metabolism ◽

Beneficial Effects ◽

Mitochondrial Functions ◽

Herbal Formulations

Background: Chronic kidney disease (CKD) is a leading cause of morbidity and mortality. Mitochondrial dysfunction has been implicated as a key factor in the development of CKD. According to traditional Chinese medicine (TCM) theory, many Chinese Yang/Qi-invigorating botanical drugs/herbal formulations have been shown to produce promising outcomes in the clinical management of CKD. Experimental studies have indicated that the health-promoting action of Yang/Qi invigoration in TCM is related to the up-regulation of mitochondrial energy generation and antioxidant status.Objective: In this review, we aim to test whether Chinese Yang/Qi-invigorating tonic botanical drugs/herbal formulations can provide medical benefits in CKD and its complications. And we also explore the possible involvement of mitochondrial-associated signaling pathway underlying the beneficial effects of Yang/Qi invigoration in TCM.Methods: A systematic search of “PubMed”, “China National Knowledge Infrastructure (CNKI)” and “Google Scholar” was carried out to collect all the available articles in English or Chinese related to Chinese Yang/Qi-invigorating tonic botanical drugs/herbal formulations and their effects on mitochondrial function and chronic kidney disease.Result and Discussion: The relationship between the progression of CKD and mitochondrial function is discussed. The effects of Chinese Yang/Qi-invigorating tonic botanical drugs/herbal formulations and their active ingredients, including phytosterols/triterpenes, flavonoids, and dibenzocyclooctadiene lignans, on CKD and related alterations in mitochondrial signaling pathways are also presented in this review. In the future, exploration of the possible beneficial effects and clinical studies of more Yang- and Qi-invigorating botanical drugs/herbal formulations in the prevention and/or/treatment of CKD and the molecular mechanisms relating to the enhancement of mitochondrial functions warrants further investigation.Conclusion: Given the critical role of mitochondrial function in safeguarding renal functional integrity, the enhancement of mitochondrial energy metabolism and antioxidant status in kidney tissue is likely involved in renal protection. Future studies on the biochemical and chemical basis underlying the effects of Chinese Yang/Qi-invigorating tonic botanical drugs/herbal formulations from a mitochondrial perspective will hopefully provide novel insights into the rational development of new drugs for the prevention and/or treatment of CKD.

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Mitochondrial Sorting and Assembly Machinery Subunit Sam37 in Candida albicans: Insight into the Roles of Mitochondria in Fitness, Cell Wall Integrity, and Virulence

Eukaryotic Cell ◽

10.1128/ec.05292-11 ◽

2012 ◽

Vol 11 (4) ◽

pp. 532-544 ◽

Cited By ~ 38

Author(s):

Yue Qu ◽

Branka Jelicic ◽

Filomena Pettolino ◽

Andrew Perry ◽

Tricia L. Lo ◽

...

Keyword(s):

Cell Wall ◽

Candida Albicans ◽

Mitochondrial Function ◽

Drug Tolerance ◽

Cell Wall Integrity ◽

Mitochondrial Outer Membrane ◽

Wall Structure ◽

Content Type ◽

Mitochondrial Functions ◽

Insight Into

ABSTRACT Recent studies indicate that mitochondrial functions impinge on cell wall integrity, drug tolerance, and virulence of human fungal pathogens. However, the mechanistic aspects of these processes are poorly understood. We focused on the mitochondrial outer membrane SAM ( S orting and A ssembly M achinery) complex subunit Sam37 in Candida albicans . Inactivation of SAM37 in C. albicans leads to a large reduction in fitness, a phenotype not conserved with the model yeast Saccharomyces cerevisiae . Our data indicate that slow growth of the sam37ΔΔ mutant results from mitochondrial DNA loss, a new function for Sam37 in C. albicans , and from reduced activity of the essential SAM complex subunit Sam35. The sam37ΔΔ mutant was hypersensitive to drugs that target the cell wall and displayed altered cell wall structure, supporting a role for Sam37 in cell wall integrity in C. albicans . The sensitivity of the mutant to membrane-targeting antifungals was not significantly altered. The sam37ΔΔ mutant was avirulent in the mouse model, and bioinformatics showed that the fungal Sam37 proteins are distant from their animal counterparts and could thus represent potential drug targets. Our study provides the first direct evidence for a link between mitochondrial function and cell wall integrity in C. albicans and is further relevant for understanding mitochondrial function in fitness, antifungal drug tolerance, and virulence of this major pathogen. Beyond the relevance to fungal pathogenesis, this work also provides new insight into the mitochondrial and cellular roles of the SAM complex in fungi.

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Nutrients, Mitochondrial Function, and Perinatal Health

Nutrients ◽

10.3390/nu12072166 ◽

2020 ◽

Vol 12 (7) ◽

pp. 2166 ◽

Cited By ~ 3

Author(s):

Ameyalli M Rodríguez-Cano ◽

Claudia C Calzada-Mendoza ◽

Guadalupe Estrada-Gutierrez ◽

Jonatan A Mendoza-Ortega ◽

Otilia Perichart-Perera

Keyword(s):

Mitochondrial Dysfunction ◽

Mitochondrial Function ◽

Infant Health ◽

Energy Requirement ◽

Critical Role ◽

Essential Elements ◽

Long Term Effects ◽

Maternal And Infant Health ◽

Adverse Pregnancy ◽

One Carbon Metabolism

Mitochondria are active independent organelles that not only meet the cellular energy requirement but also regulate central cellular activities. Mitochondria can play a critical role in physiological adaptations during pregnancy. Differences in mitochondrial function have been found between healthy and complicated pregnancies. Pregnancy signifies increased nutritional requirements to support fetal growth and the metabolism of maternal and fetal tissues. Nutrient availability regulates mitochondrial metabolism, where excessive macronutrient supply could lead to oxidative stress and contribute to mitochondrial dysfunction, while micronutrients are essential elements for optimal mitochondrial processes, as cofactors in energy metabolism and/or as antioxidants. Inadequate macronutrient and micronutrient consumption can result in adverse pregnancy outcomes, possibly through mitochondrial dysfunction, by impairing energy supply, one-carbon metabolism, biosynthetic pathways, and the availability of metabolic co-factors which modulate the epigenetic processes capable of establishing significant short- and long-term effects on infant health. Here, we review the importance of macronutrients and micronutrients on mitochondrial function and its influence on maternal and infant health.

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