scholarly journals Mitochondrial and Metabolic dysfunction in Friedreich ataxia: Update on Pathophysiological relevance and clinical interventions

2021 ◽  
Author(s):  
David Lynch ◽  
Garrett Farmer
Keyword(s):  
Friedreich Ataxia ◽  
Mitochondrial Protein ◽  
Metabolic Imaging ◽  
Metabolic Dysfunction ◽  
Iron Sulfur Cluster ◽  
In Vivo Models ◽  
Cellular Models ◽  
Imaging Methodology ◽  
Relative Deficiency

Friedreich ataxia is a recessive disorder resulting from relative deficiency of the mitochondrial protein frataxin. Frataxin functions in the process of iron sulfur cluster synthesis. In this review, we update some of the processes downstream of frataxin deficiency that may mediate the pathophysiology. Based on cellular models, in vivo models and observations of patients, ferroptosis may play a major role in the pathogenesis of FRDA along with depletion of antioxidant reserves and abnormalities of mitochondrial biogenesis. Ongoing clinical trials with ferroptosis inhibitors and Nrf2 activators are now targeting each of the processes. In addition, better understanding of the mitochondrial events in FRDA may allow the development of improved imaging methodology for assessing the disorder. Though not technologically feasible at present, metabolic imaging approaches may provide a direct methodology to understand the mitochondrial changes occurring in FRDA and provide a methodology to monitor upcoming trials of frataxin restoration.

Oxidative modification of hepatic mitochondria protein thiols: effect of chronic alcohol consumption

2004 ◽  
Vol 286 (4) ◽  
pp. G521-G527 ◽  
Author(s):  
Aparna Venkatraman ◽  
Aimee Landar ◽  
Ashley J. Davis ◽  
Elena Ulasova ◽  
Grier Page ◽  
...  
Keyword(s):  
Aldehyde Dehydrogenase ◽  
Nitrosative Stress ◽  
Mitochondrial Protein ◽  
Oxidative Modification ◽  
Mitochondrial Proteins ◽  
In Vivo Model ◽  
Chronic Alcohol ◽  
In Vivo Models ◽  
Protein Thiols

Redox modification of mitochondrial proteins is thought to play a key role in regulating cellular function, although direct evidence to support this hypothesis is limited. Using an in vivo model of mitochondrial redox stress, ethanol hepatotoxicity, the modification of mitochondrial protein thiols was examined using a proteomics approach. Specific labeling of reduced thiols in the mitochondrion from the livers of control and ethanol-fed rats was achieved by using the thiol reactive compound (4-iodobutyl)triphenylphosphonium (IBTP). This molecule selectively accumulates in the organelle and can be used to identify thiol-containing proteins. Mitochondrial proteins that have been modified are identified by decreased labeling with IBTP using two-dimensional SDS-PAGE followed by immunoblotting with an antibody directed against the triphenylphosphonium moiety of the IBTP molecule. Analyses of these data showed a significant decrease in IBTP labeling of thiols present in specific mitochondria matrix proteins from ethanol-fed rats compared with their corresponding controls. These proteins were identified as the low- Km aldehyde dehydrogenase and glucose-regulated protein 78. The decrease in IBTP labeling in aldehyde dehydrogenase was accompanied by a decrease in specific activity of the enzyme. These data demonstrate that mitochondrial protein thiol modification is associated with chronic alcohol intake and might contribute to the pathophysiology associated with hepatic injury. Taken together, we have developed a protocol to chemically tag and select thiol-modified proteins that will greatly enhance efforts to establish posttranslational redox modification of mitochondrial protein in in vivo models of oxidative or nitrosative stress.

Animal and Cellular Models of Alzheimer’s Disease: Progress, Promise, and Future Approaches

2021 ◽  
pp. 107385842110017
Author(s):  
Laura Trujillo-Estrada ◽  
Elisabeth Sanchez-Mejias ◽  
Raquel Sanchez-Varo ◽  
Juan Antonio Garcia-Leon ◽  
Cristina Nuñez-Diaz ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Transgenic Mouse ◽  
Mouse Models ◽  
Clinical Manifestations ◽  
Transgenic Mouse Models ◽  
In Vivo Models ◽  
Limited Ability ◽  
Cellular Models

Alzheimer’s disease (AD) is an incurable neurodegenerative disease affecting over 45 million people worldwide. Transgenic mouse models have made remarkable contributions toward clarifying the pathophysiological mechanisms behind the clinical manifestations of AD. However, the limited ability of these in vivo models to accurately replicate the biology of the human disease have precluded the translation of promising preclinical therapies to the clinic. In this review, we highlight several major pathogenic mechanisms of AD that were discovered using transgenic mouse models. Moreover, we discuss the shortcomings of current animal models and the need to develop reliable models for the sporadic form of the disease, which accounts for the majority of AD cases, as well as human cellular models to improve success in translating results into human treatments.

scholarly journals In Vitro and In Vivo Models of Non-Alcoholic Fatty Liver Disease: A Critical Appraisal

2020 ◽  
Vol 10 (1) ◽  
pp. 36
Author(s):  
Pierre-Antoine Soret ◽  
Julie Magusto ◽  
Chantal Housset ◽  
Jérémie Gautheron
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Preclinical Research ◽  
In Vivo Models ◽  
Alcoholic Fatty Liver ◽  
Cellular Models ◽  
Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD), including non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH), represents the hepatic manifestation of obesity and metabolic syndrome. Due to the spread of the obesity epidemic, NAFLD is becoming the most common chronic liver disease and one of the principal indications for liver transplantation. However, no pharmacological treatment is currently approved to prevent the outbreak of NASH, which leads to fibrosis and cirrhosis. Preclinical research is required to improve our knowledge of NAFLD physiopathology and to identify new therapeutic targets. In the present review, we summarize advances in NAFLD preclinical models from cellular models, including new bioengineered platforms, to in vivo models, with a particular focus on genetic and dietary mouse models. We aim to discuss the advantages and limits of these different models.

scholarly journals HGG-25. PRMT5 PROMOTES TUMOR GROWTH BY MAINTAINING STEMNESS OF PEDIATRIC HIGH-GRADE GLIOMA CELLS

2021 ◽  
Vol 23 (Supplement_1) ◽  
pp. i22-i22
Author(s):  
John DeSisto ◽  
Aaron Knox ◽  
Hannah Chatwin ◽  
Ilango Balakrishnan ◽  
Sujatha Venkataraman ◽  
...  
Keyword(s):  
Stem Cells ◽  
Tumor Growth ◽  
Chemotherapeutic Agents ◽  
High Grade ◽  
Epigenetic Changes ◽  
Apoptosis Resistance ◽  
Self Renewal ◽  
In Vivo Models ◽  
Cellular Models

Abstract Background Pediatric high-grade gliomas (pHGG) are aggressive tumors that together constitute the most common cause of childhood cancer mortality. Tumor stem cells that drive proliferation of pHGG resist chemotherapy and radiation, complicating treatment. The arginine methyltransferase PRMT5 maintains self-renewal in neural stem cells through epigenetic modifications. We hypothesized that PRMT5, which we identified as a potential driver of diffuse midline glioma (DMG) through an shRNA screen, plays a similar role in pHGG. Methods Using lentiviral delivery of shRNA, we knocked down (KD) PRMT5 in cortical pHGG and DMG cell lines and performed phenotypic, mechanistic and self-renewal assays. We irradiated PRMT5 KD and control cells to study sensitization. We orthotopically injected mice with PRMT5 KD pHGG cells, and with DMG cells in which PRMT5 was knocked out (KO) using CRISPR-Cas. Results In cellular models of cortical pHGG and DMG, PRMT5 KD significantly reduced proliferation, inhibited cell cycle progression, increased apoptosis resistance, and decreased self-renewing cell frequency. A relative shift of PRMT5 from the cytoplasm to the nucleus accompanied differentiation induced by PRMT5 KD. Epigenetic changes accompanying PRMT5 KD included increased H3K27me3, a global transcription inhibitor, and decreased H3K27M expression in DMG. PRMT5 KD sensitized pHGG cells to radiation, increasing cell death 17–30%. PRMT5 KD/KO significantly increased survival in mice and decreased tumor aggressiveness and proliferation, but mice still died of tumor-related effects. Conclusions PRMT5 maintains self-renewal and drives proliferation in preclinical pHGG models. In cellular and in vivo models, PRMT5 KD/KO produces epigenetic changes, including increased H3K27me3 levels and diminished H3K27M, that may reduce proliferation and self-renewal. Future work includes elucidation of the mechanisms by which PRMT5 produces the observed changes. Because PRMT5 KD/KO does not eliminate tumor growth, we plan to further study combining PRMT5 KD/KO and clinical-grade small molecule PRMT5 inhibitors with radiation and chemotherapeutic agents.

scholarly journals Carnitine Palmitoyltransferase 1 Regulates Prostate Cancer Growth under Hypoxia

Cancers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 6302
Author(s):  
Leslimar Rios-Colon ◽  
Pawan Kumar ◽  
Susy Kim ◽  
Mitu Sharma ◽  
Yixin Su ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Vector Control ◽  
Tumor Volume ◽  
Mitochondrial Protein ◽  
Carnitine Palmitoyltransferase ◽  
In Vivo Models ◽  
Hypoxic Conditions ◽  
Carnitine Palmitoyltransferase 1 ◽  
Sphere Formation

Hypoxia and hypoxia-related biomarkers are the major determinants of prostate cancer (PCa) aggressiveness. Therefore, a better understanding of molecular players involved in PCa cell survival under hypoxia could offer novel therapeutic targets. We previously reported a central role of mitochondrial protein carnitine palmitoyltransferase (CPT1A) in PCa progression, but its role in regulating PCa survival under hypoxia remains unknown. Here, we employed PCa cells (22Rv1 and MDA-PCa-2b) with knockdown or overexpression of CPT1A and assessed their survival under hypoxia, both in cell culture and in vivo models. The results showed that CPT1A knockdown in PCa cells significantly reduced their viability, clonogenicity, and sphere formation under hypoxia, while its overexpression increased their proliferation, clonogenicity, and sphere formation. In nude mice, 22Rv1 xenografts with CPT1A knockdown grew significantly slower compared to vector control cells (~59% reduction in tumor volume at day 29). On the contrary, CPT1A-overexpressing 22Rv1 xenografts showed higher tumor growth compared to vector control cells (~58% higher tumor volume at day 40). Pathological analyses revealed lesser necrotic areas in CPT1A knockdown tumors and higher necrotic areas in CPT1A overexpressing tumors. Immunofluorescence analysis of tumors showed that CPT1A knockdown strongly compromised the hypoxic areas (pimonidazole+), while CPT1A overexpression resulted in more hypoxia areas with strong expression of proliferation biomarkers (Ki67 and cyclin D1). Finally, IHC analysis of tumors revealed a significant decrease in VEGF or VEGF-D expression but without significant changes in biomarkers associated with microvessel density. These results suggest that CPT1A regulates PCa survival in hypoxic conditions and might contribute to their aggressiveness.

scholarly journals Extracellular cues accelerate neurogenesis of induced pluripotent stem cell derived neurons

2021 ◽  
Author(s):  
Elizabeth Sharlow ◽  
Danielle Llaneza ◽  
Anna Mendelson ◽  
Garnett Mingledorff ◽  
Veronica Porterfield ◽  
...  
Keyword(s):  
Stem Cell ◽  
Pluripotent Stem Cell ◽  
Induced Pluripotent Stem Cell ◽  
Medium Composition ◽  
Neuronal Cultures ◽  
Feeder Layer ◽  
In Vivo Models ◽  
Cellular Models ◽  
Induced Pluripotent

Neurogenesis is a complex process encompassing neuronal progenitor cell expansion/proliferation and differentiation, followed by neuron maturation. In vivo models are most commonly used to study neurogenesis; however, human induced pluripotent stem cell-derived (iPSC) neurons are increasingly used to establish cellular models of human neurological processes. Unfortunately, the differentiation and maturation of iPSC-derived neurons varies in methodology, is asynchronous, and has restricted experimental utility because of extended differentiation/maturation times. To accelerate and standardize iPS neuronal maturation, we differentiated and matured feeder layer-free iPSC-derived neuronal cultures under physiological oxygen levels (5%), and modified the underlying extracellular matrix and medium composition. Our results demonstrate that calretinin gene expression occurred earlier under our optimized iPS conditions and the corresponding neurogenesis burst associated with proliferative expansion occurred more synchronously, reliably emerging two and three weeks after differentiation. As expected, the expression of mature neuronal markers (i.e., NeuN+/Calbindin+) started at 4-weeks post-differentiation. qPCR microarray, western blot and single cell analyses using high content imaging indicated that 4-week iPS neuronal cultures were non-cycling with decreased expression of cyclin D1 and Ki67. Our data demonstrate that extracellular cues influence the kinetics of neurogenesis models and that feeder layer-free iPSC-derived neurogenesis can be reproducibly miniaturized.

Fatty Acids and Effects on In Vitro and In Vivo Models of Liver Steatosis

2019 ◽  
Vol 26 (19) ◽  
pp. 3439-3456 ◽  
Author(s):  
Laura Vergani
Keyword(s):  
Fatty Acids ◽  
Animal Models ◽  
Fatty Liver ◽  
Liver Steatosis ◽  
In Vivo Models ◽  
Alcoholic Fatty Liver ◽  
Cellular Models ◽  
Advantages And Disadvantages

Background: Fatty liver, or steatosis, is a condition of excess accumulation of lipids, mainly under form of triglycerides (TG), in the liver, and it is the hallmark of non-alcoholic fatty liver disease (NAFLD). NAFLD is the most common liver disorder world-wide and it has frequently been associated with obesity, hyperlipidemia and insulin resistance. Free fatty acids (FA) are the major mediators of hepatic steatosis; patients with NAFLD have elevated levels of circulating FA that correlate with disease severity. Methods: Steatosis is a reversible condition that can be resolved with changed behaviors, or that can progress towards more severe liver damages such as steatohepatitis (NASH), fibrosis and cirrhosis. In NAFLD, FA of exogenous or endogenous origin accumulate in the hepatocytes and trigger liver damages. Excess TG are stored in cytosolic lipid droplets (LDs) that are dynamic organelles acting as hubs for lipid metabolism. Results: In the first part of this review, we briefly reassumed the main classes of FA and their chemical classification as a function of the presence and number of double bonds, their metabolic pathways and effects on human health. Then, we summarized the main genetic and diet-induced animal models of NAFLD, as well as the cellular models of NAFLD. Conclusions: In recent years, both the diet-induced animal models of NAFLD as well as the cellular models of NAFLD have found ever more application to investigate the mechanisms involved in NAFLD, and we referred to their advantages and disadvantages.

scholarly journals Conditioned Medium from Cells Overexpressing TDP-43 Alters the Metabolome of Recipient Cells

Cells ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 2198
Author(s):  
Rudolf Hergesheimer ◽  
Débora Lanznaster ◽  
Jérôme Bourgeais ◽  
Olivier Hérault ◽  
Patrick Vourc’h ◽  
...  
Keyword(s):  
Conditioned Medium ◽  
Motor Neurons ◽  
Brain Extract ◽  
Metabolic Dysfunction ◽  
Active Response ◽  
In Vivo Models ◽  
Altered Metabolism ◽  
Extracellular Environment ◽  
Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease caused by the progressive death of both upper and lower motor neurons. The disease presents a poor prognosis, and patients usually die 2–5 years after the onset of symptoms. The hallmark of this disease is the presence of phosphorylated and ubiquitinated aggregates containing trans-active response DNA-binding protein-43 (TDP-43) in the cytoplasm of motor neurons. TDP-43 pathology has been associated with multiple pathways in ALS, such as metabolic dysfunction found in patients and in in vivo models. Recently, it has been described as a “prion-like” protein, as studies have shown its propagation in cell culture from ALS brain extract or overexpressed TDP-43 in co-culture and conditioned medium, resulting in cytotoxicity. However, the cellular alterations that are associated with this cytotoxicity require further investigation. Here, we investigated the effects of conditioned medium from HEK293T (Human Embryonic Kidney 293T) cells overexpressing TDP-43 on cellular morphology, proliferation, death, and metabolism. Although we did not find evidence of TDP-43 propagation, we observed a toxicity of TDP-43-conditioned medium and altered metabolism. These results, therefore, suggest (1) that cells overexpressing TDP-43 produce an extracellular environment that can perturb other cells and (2) that TDP-43 propagation alone may not be the only potentially cytotoxic cell-to-cell mechanism.

Neuronal death signaling pathways triggered by mutant LRRK2

2017 ◽  
Vol 45 (1) ◽  
pp. 123-129 ◽  
Author(s):  
Hardy J. Rideout
Keyword(s):  
Cell Death ◽  
Neuronal Death ◽  
Specific Cell ◽  
Clear Understanding ◽  
Gene Encoding ◽  
In Vivo Models ◽  
Cellular Models ◽  
Inhibitory Function ◽  
Mutant Lrrk2

Autosomal dominantly inherited mutations in the gene encoding leucine-rich repeat kinase 2 (LRRK2) are the most common genetic cause of Parkinson's disease. While considerable progress has been made in understanding its function and the many different cellular activities in which it participates, a clear understanding of the mechanism(s) of the induction of neuronal death by mutant forms of LRRK2 remains elusive. Although several in vivo models have documented the progressive loss of dopaminergic neurons of the substantia nigra, more complete interrogations of the modality of neuronal death have been gained from cellular models. Overexpression of mutant LRRK2 in neuronal-like cell lines or in primary neurons induces an apoptotic type of cell death involving components of the extrinsic as well as intrinsic death pathways. While informative, these studies are limited by their reliance upon isolated neuronal cells; and the pathways triggered by mutant LRRK2 in neurons may be further refined or modulated by extracellular signals. Nevertheless, the identification of specific cell death-associated signaling events set in motion by the dominant action of mutant LRRK2, the loss of an inhibitory function of wild-type LRRK2, or a combination of the two, expands the landscape of potential therapeutic targets for future intervention in the clinic.

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