Human INCL fibroblasts display abnormal mitochondrial and lysosomal networks and heightened susceptibility to ROS-induced cell death

AbstractInfantile Neuronal Ceroid Lipofuscinosis (INCL) is a pediatric neurodegenerative disorder characterized by progressive retinal and central nervous system deterioration during infancy. This lysosomal storage disorder results from a deficiency in the Palmitoyl Protein Thioesterase 1 (PPT1) enzyme - a lysosomal hydrolase which cleaves fatty acid chains such as palmitate from lipid-modified proteins. In the absence of PPT1 activity, these proteins fail to be degraded, leading to the accumulation of autofluorescence storage material in the lysosome. The underlying molecular mechanisms leading to INCL pathology remain poorly understood. A role for oxidative stress has been postulated, yet little evidence has been reported to support this possibility. Here we present a comprehensive cellular characterization of human PPT1-deficient fibroblast cells harboring Met1Ile and Tyr247His compound heterozygous mutations. We detected autofluorescence storage material and observed distinct organellar abnormalities of the lysosomal and mitochondrial structures, which supported previous postulations about the role of ER, mitochondria and oxidative stress in INCL. An increase in the number of lysosomal structures was found in INCL patient fibroblasts, which suggested an upregulation of lysosomal biogenesis, and an association with endoplasmic reticulum stress response. The mitochondrial network also displayed abnormal spherical punctate morphology instead of normal elongated tubules with extensive branching, supporting the involvement of mitochondrial and oxidative stress in INCL cell death. Autofluorescence accumulation and lysosomal pathologies can be mitigated in the presence of conditioned wild type media suggesting that a partial restoration via passive introduction of the enzyme into the cellular environment may be possible. We also demonstrated, for the first time, that human INCL fibroblasts have a heightened susceptibility to exogenous reactive oxygen species (ROS)-induced cell death, which suggested an elevated basal level of endogenous ROS in the mutant cell. Collectively, these findings support the role of intracellular organellar networks in INCL pathology, possibly due to oxidative stress.

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Human INCL fibroblasts display abnormal mitochondrial and lysosomal networks and heightened susceptibility to ROS-induced cell death

PLoS ONE ◽

10.1371/journal.pone.0239689 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0239689 ◽

Cited By ~ 1

Author(s):

Bailey Balouch ◽

Halle Nagorsky ◽

Truc Pham ◽

James Thai LaGraff ◽

Quynh Chu-LaGraff

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Molecular Mechanisms ◽

Neurodegenerative Disorder ◽

Endoplasmic Reticulum Stress Response ◽

Compound Heterozygous ◽

Storage Material ◽

Cellular Environment ◽

And Oxidative Stress

Infantile Neuronal Ceroid Lipofuscinosis (INCL) is a pediatric neurodegenerative disorder characterized by progressive retinal and central nervous system deterioration during infancy. This lysosomal storage disorder results from a deficiency in the Palmitoyl Protein Thioesterase 1 (PPT1) enzyme—a lysosomal hydrolase which cleaves fatty acid chains such as palmitate from lipid-modified proteins. In the absence of PPT1 activity, these proteins fail to be degraded, leading to the accumulation of autofluorescence storage material in the lysosome. The underlying molecular mechanisms leading to INCL pathology remain poorly understood. A role for oxidative stress has been postulated, yet little evidence has been reported to support this possibility. Here we present a comprehensive cellular characterization of human PPT1-deficient fibroblast cells harboring Met1Ile and Tyr247His compound heterozygous mutations. We detected autofluorescence storage material and observed distinct organellar abnormalities of the lysosomal and mitochondrial structures, which supported previous postulations about the role of ER, mitochondria and oxidative stress in INCL. An increase in the number of lysosomal structures was found in INCL patient fibroblasts, which suggested an upregulation of lysosomal biogenesis, and an association with endoplasmic reticulum stress response. The mitochondrial network also displayed abnormal spherical punctate morphology instead of normal elongated tubules with extensive branching, supporting the involvement of mitochondrial and oxidative stress in INCL cell death. Autofluorescence accumulation and lysosomal pathologies can be mitigated in the presence of conditioned wild type media suggesting that a partial restoration via passive introduction of the enzyme into the cellular environment may be possible. We also demonstrated, for the first time, that human INCL fibroblasts have a heightened susceptibility to exogenous reactive oxygen species (ROS)-induced cell death, which suggested an elevated basal level of endogenous ROS in the mutant cell. Collectively, these findings support the role of intracellular organellar networks in INCL pathology, possibly due to oxidative stress.

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LncRNA SNHG12 Improves Cerebral Ischemic-reperfusion Injury by Activating SIRT1/FOXO3a Pathway through I nhibition of Autophagy and Oxidative Stress

Current Neurovascular Research ◽

10.2174/1567202617666200727142019 ◽

2020 ◽

Vol 17 (4) ◽

pp. 394-401

Author(s):

Yuanhua Wu ◽

Yuan Huang ◽

Jing Cai ◽

Donglan Zhang ◽

Shixi Liu ◽

...

Keyword(s):

Oxidative Stress ◽

Molecular Mechanisms ◽

Ischemia Reperfusion ◽

Critical Role ◽

Cell Activity ◽

Ht22 Cells ◽

Cerebral Ischemic ◽

Cerebral Ischemic Reperfusion ◽

And Oxidative Stress

Background: Ischemia/reperfusion (I/R) injury involves complex biological processes and molecular mechanisms such as autophagy. Oxidative stress plays a critical role in the pathogenesis of I/R injury. LncRNAs are the regulatory factor of cerebral I/R injury. Methods: This study constructs cerebral I/R model to investigate role of autophagy and oxidative stress in cerebral I/R injury and the underline regulatory mechanism of SIRT1/ FOXO3a pathway. In this study, lncRNA SNHG12 and FOXO3a expression was up-regulated and SIRT1 expression was down-regulated in HT22 cells of I/R model. Results: Overexpression of lncRNA SNHG12 significantly increased the cell viability and inhibited cerebral ischemicreperfusion injury induced by I/Rthrough inhibition of autophagy. In addition, the transfected p-SIRT1 significantly suppressed the release of LDH and SOD compared with cells co-transfected with SIRT1 and FOXO3a group and cells induced by I/R and transfected with p-SNHG12 group and overexpression of cells co-transfected with SIRT1 and FOXO3 further decreased the I/R induced release of ROS and MDA. Conclusion: In conclusion, lncRNA SNHG12 increased cell activity and inhibited oxidative stress through inhibition of SIRT1/FOXO3a signaling-mediated autophagy in HT22 cells of I/R model. This study might provide new potential therapeutic targets for further investigating the mechanisms in cerebral I/R injury and provide.

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Molecular Mechanisms of Obesity-Linked Cardiac Dysfunction: An Up-Date on Current Knowledge

Cells ◽

10.3390/cells10030629 ◽

2021 ◽

Vol 10 (3) ◽

pp. 629

Author(s):

Jorge Gutiérrez-Cuevas ◽

Ana Sandoval-Rodriguez ◽

Alejandra Meza-Rios ◽

Hugo Christian Monroy-Ramírez ◽

Marina Galicia-Moreno ◽

...

Keyword(s):

Oxidative Stress ◽

Cardiac Dysfunction ◽

Molecular Mechanisms ◽

Current Knowledge ◽

Peroxisome Proliferator ◽

White Adipocyte ◽

Peroxisome Proliferator Activated Receptors ◽

And Oxidative Stress

Obesity is defined as excessive body fat accumulation, and worldwide obesity has nearly tripled since 1975. Excess of free fatty acids (FFAs) and triglycerides in obese individuals promote ectopic lipid accumulation in the liver, skeletal muscle tissue, and heart, among others, inducing insulin resistance, hypertension, metabolic syndrome, type 2 diabetes (T2D), atherosclerosis, and cardiovascular disease (CVD). These diseases are promoted by visceral white adipocyte tissue (WAT) dysfunction through an increase in pro-inflammatory adipokines, oxidative stress, activation of the renin-angiotensin-aldosterone system (RAAS), and adverse changes in the gut microbiome. In the heart, obesity and T2D induce changes in substrate utilization, tissue metabolism, oxidative stress, and inflammation, leading to myocardial fibrosis and ultimately cardiac dysfunction. Peroxisome proliferator-activated receptors (PPARs) are involved in the regulation of carbohydrate and lipid metabolism, also improve insulin sensitivity, triglyceride levels, inflammation, and oxidative stress. The purpose of this review is to provide an update on the molecular mechanisms involved in obesity-linked CVD pathophysiology, considering pro-inflammatory cytokines, adipokines, and hormones, as well as the role of oxidative stress, inflammation, and PPARs. In addition, cell lines and animal models, biomarkers, gut microbiota dysbiosis, epigenetic modifications, and current therapeutic treatments in CVD associated with obesity are outlined in this paper.

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Effects of Levosimendan on Inflammation and Oxidative Stress Pathways in a Lipopolysaccharide-Stimulated Human Endothelial Cell Model

Biological Research For Nursing ◽

10.1177/1099800419861694 ◽

2019 ◽

Vol 21 (5) ◽

pp. 466-472 ◽

Cited By ~ 1

Author(s):

Raquel Rodríguez-González ◽

Piero Pollesello ◽

Aurora Baluja ◽

Julián Álvarez

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Endothelial Cell ◽

Molecular Mechanisms ◽

Cell Model ◽

Acute Decompensated Heart Failure ◽

Umbilical Vein ◽

Organ Protection ◽

Endothelial Cell Death ◽

And Oxidative Stress

Levosimendan is a myocardial Ca2+sensitizer and opener of ATP-dependent potassium channels with inotropic, vasodilating, and cardioprotective properties. It was originally developed for the treatment of acute decompensated heart failure, but its complex mechanism of action means that it could also play a role in organ protection in response to infection. Using an in vitro approach, we explored whether levosimendan administration influenced cell responses to lipopolysaccharide (LPS). Primary human umbilical vein endothelial cells were stimulated with 1 µg/ml LPS from Escherichia coli ( E. coli). Cells were treated with levosimendan at 0, 0.1, 1, or 10 µM 3 hr later. Samples were taken 24 hr after treatment to measure cell necrosis, apoptosis, pro-inflammatory mediators (interleukin 6 [IL-6] and toll-like receptor 4 [TLR4]), and oxidative stress (total reactive oxygen species/reactive nitrogen species [ROS/RNS]). Levosimendan at 1 and 10 µM protected against LPS-induced endothelial cell death and reduced TLR4 expression ( p < .05). All doses reduced levels of IL-6 and ROS/RNS ( p < .05). Findings suggest that levosimendan may exert protective effects against endothelial cell death in this model via attenuation of inflammation and oxidative stress pathways. Future studies might explore the potential beneficial role of levosimendan in modulating molecular mechanisms triggered by infections.

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Role of retinoic acid and oxidative stress in embryonic stem cell death and neuronal differentiation

FEBS Letters ◽

10.1016/0014-5793(96)00088-9 ◽

1996 ◽

Vol 381 (1-2) ◽

pp. 93-97 ◽

Cited By ~ 49

Author(s):

S. Castro-Obregón ◽

L. Covarrubias

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Stem Cell ◽

Retinoic Acid ◽

Embryonic Stem Cell ◽

Neuronal Differentiation ◽

Embryonic Stem ◽

And Oxidative Stress

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Alzheimer’s Pathogenesis and Its Link to the Mitochondrion

Oxidative Medicine and Cellular Longevity ◽

10.1155/2015/803942 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 22

Author(s):

C. Simoncini ◽

D. Orsucci ◽

E. Caldarazzo Ienco ◽

G. Siciliano ◽

U. Bonuccelli ◽

...

Keyword(s):

Oxidative Stress ◽

Mitochondrial Dysfunction ◽

Cognitive Functions ◽

Neurodegenerative Disorder ◽

The Elderly ◽

Mitochondria Dysfunction ◽

Neurodegenerative Process ◽

Mitochondrial Impairment ◽

And Oxidative Stress

Alzheimer’s disease (AD) is the most common form of dementia in the elderly. This neurodegenerative disorder is clinically characterized by impairment of cognitive functions and changes in behaviour and personality. The pathogenesis of AD is still unclear. Recent evidence supports some role of mitochondria dysfunction and oxidative stress in the development of the neurodegenerative process. In this review, we discuss the role of mitochondrial dysfunction in AD, focusing on the mechanisms that lead to mitochondrial impairment, oxidative stress, and neurodegeneration, a “vicious circle” that ends in dementia.

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SIRT3 Is a Stress-Responsive Deacetylase in Cardiomyocytes That Protects Cells from Stress-Mediated Cell Death by Deacetylation of Ku70

Molecular and Cellular Biology ◽

10.1128/mcb.00426-08 ◽

2008 ◽

Vol 28 (20) ◽

pp. 6384-6401 ◽

Cited By ~ 334

Author(s):

Nagalingam R. Sundaresan ◽

Sadhana A. Samant ◽

Vinodkumar B. Pillai ◽

Senthilkumar B. Rajamohan ◽

Mahesh P. Gupta

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Gene Regulation ◽

Essential Role ◽

Short Form ◽

Biological Functions ◽

Proapoptotic Protein ◽

Long Form ◽

And Oxidative Stress

ABSTRACT There are seven SIRT isoforms in mammals, with diverse biological functions including gene regulation, metabolism, and apoptosis. Among them, SIRT3 is the only sirtuin whose increased expression has been shown to correlate with an extended life span in humans. In this study, we examined the role of SIRT3 in murine cardiomyocytes. We found that SIRT3 is a stress-responsive deacetylase and that its increased expression protects myocytes from genotoxic and oxidative stress-mediated cell death. We show that, like human SIRT3, mouse SIRT3 is expressed in two forms, a ∼44-kDa long form and a ∼28-kDa short form. Whereas the long form is localized in the mitochondria, nucleus, and cytoplasm, the short form is localized exclusively in the mitochondria of cardiomyocytes. During stress, SIRT3 levels are increased not only in mitochondria but also in the nuclei of cardiomyocytes. We also identified Ku70 as a new target of SIRT3. SIRT3 physically binds to Ku70 and deacetylates it, and this promotes interaction of Ku70 with the proapoptotic protein Bax. Thus, under stress conditions, increased expression of SIRT3 protects cardiomyocytes, in part by hindering the translocation of Bax to mitochondria. These studies underscore an essential role of SIRT3 in the survival of cardiomyocytes in stress situations.

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Abstract 3731: TSC deficiency unmasks a novel protective role of RIP1/RIP3 signaling against mitochondrial and oxidative stress-induced cell death

10.1158/1538-7445.am2016-3731 ◽

2016 ◽

Author(s):

Piotr T. Filipczak ◽

Cindy Thomas ◽

Wenshu Chen ◽

Andrew Salzman ◽

Jacob D. McDonald ◽

...

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Protective Role ◽

And Oxidative Stress

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Nitric Oxide: Exploring the Contextual Link with Alzheimer’s Disease

Oxidative Medicine and Cellular Longevity ◽

10.1155/2016/7205747 ◽

2016 ◽

Vol 2016 ◽

pp. 1-10 ◽

Cited By ~ 40

Author(s):

Nicholas Asiimwe ◽

Seung Geun Yeo ◽

Min-Sik Kim ◽

Junyang Jung ◽

Na Young Jeong

Keyword(s):

Nitric Oxide ◽

Molecular Mechanisms ◽

Neurodegenerative Disorder ◽

The Body ◽

Bioactive Molecules ◽

Therapeutic Approaches ◽

Cellular Debris ◽

And Oxidative Stress ◽

Proinflammatory Factors

Neuronal inflammation is a systematically organized physiological step often triggered to counteract an invading pathogen or to rid the body of damaged and/or dead cellular debris. At the crux of this inflammatory response is the deployment of nonneuronal cells: microglia, astrocytes, and blood-derived macrophages. Glial cells secrete a host of bioactive molecules, which include proinflammatory factors and nitric oxide (NO). From immunomodulation to neuromodulation, NO is a renowned modulator of vast physiological systems. It essentially mediates these physiological effects by interacting with cyclic GMP (cGMP) leading to the regulation of intracellular calcium ions. NO regulates the release of proinflammatory molecules, interacts with ROS leading to the formation of reactive nitrogen species (RNS), and targets vital organelles such as mitochondria, ultimately causing cellular death, a hallmark of many neurodegenerative diseases. AD is an enervating neurodegenerative disorder with an obscure etiology. Because of accumulating experimental data continually highlighting the role of NO in neuroinflammation and AD progression, we explore the most recent data to highlight in detail newly investigated molecular mechanisms in which NO becomes relevant in neuronal inflammation and oxidative stress-associated neurodegeneration in the CNS as well as lay down up-to-date knowledge regarding therapeutic approaches targeting NO.

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