scholarly journals Effect of rapamycin on mitochondria and lysosomes in fibroblasts from patients with mtDNA mutations

2021 ◽  
Author(s):  
Nashwa Cheema ◽  
Jessie M Cameron ◽  
David A Hood
Keyword(s):  
Cell Lines ◽  
Mitochondrial Function ◽  
Mitochondrial Respiration ◽  
Current Treatment ◽  
Healthy Controls ◽  
Cellular Mechanisms ◽  
Mitochondrial Import ◽  
Lysosomal Function ◽  
Mtdna Mutations ◽  
Patient Cell

Maintaining mitochondrial function and dynamics is crucial for cellular health. In muscle, defects in mitochondria result in severe myopathies where accumulation of damaged mitochondria causes deterioration and dysfunction. Importantly, understanding the role of mitochondria in disease is a necessity to determine future therapeutics. One of the most common myopathies is mitochondrial encephalopathy lactic acidosis stroke-like episodes (MELAS), which has no current treatment. Recently, MELAS patients treated with rapamycin exhibited improved clinical outcomes. However, the cellular mechanisms of rapamycin effects in MELAS patients are currently unknown. In this study, we used cultured skin fibroblasts as a window into the mitochondrial dysfunction evident in MELAS cells, as well as to study the mechanisms of rapamycin action, compared to control, healthy individuals. We observed that mitochondria from patients were fragmented, had a 3-fold decline in the average speed of motility, a 2-fold reduced mitochondrial membrane potential and a 1.5-2-fold decline in basal respiration. Despite the reduction in mitochondrial function, mitochondrial import protein Tim23 was elevated in patient cell lines. MELAS fibroblasts had increased MnSOD, p62 and lysosomal function when compared to healthy controls. Treatment of MELAS fibroblasts with rapamycin for 24 hrs resulted in increased mitochondrial respiration compared to control cells, a higher lysosome content, and a greater localization of mitochondria to lysosomes. Despite the reduction in mitochondrial function, mitochondrial import protein Tim23 was elevated in patient cell lines. MELAS fibroblasts had increased MnSOD, p62 and lysosomal function when compared to healthy controls. Treatment of MELAS fibroblasts with rapamycin for 24 hrs resulted in increased mitochondrial respiration compared to control cells, a higher lysosome content, and a greater localization of mitochondria to lysosomes.Our studies suggest that rapamycin has the potential to improve cellular health even in the presence of mtDNA defects, primarily via an increase in lysosomal content.

scholarly journals Effect of rapamycin on mitochondria and lysosomes in fibroblasts from patients with mtDNA mutations

2021 ◽  
Author(s):  
Nashwa J. Cheema ◽  
Jessie M. Cameron ◽  
David A. Hood
Keyword(s):  
Mitochondrial Function ◽  
Mitochondrial Membrane ◽  
Current Treatment ◽  
Basal Respiration ◽  
Healthy Individuals ◽  
Cellular Mechanisms ◽  
Mtdna Mutations ◽  
Cultured Skin ◽  
Patient Cell

Maintaining mitochondrial function and dynamics is crucial for cellular health. In muscle, defects in mitochondria result in severe myopathies where accumulation of damaged mitochondria causes deterioration and dysfunction. Importantly, understanding the role of mitochondria in disease is a necessity to determine future therapeutics. One of the most common myopathies is mitochondrial encephalopathy lactic acidosis stroke-like episodes (MELAS), which has no current treatment. Recently, MELAS patients treated with rapamycin exhibited improved clinical outcomes. However, the cellular mechanisms of rapamycin effects in MELAS patients are currently unknown. In this study, we used cultured skin fibroblasts as a window into the mitochondrial dysfunction evident in MELAS cells, as well as to study the mechanisms of rapamycin action, compared to control, healthy individuals. We observed that mitochondria from patients were fragmented, had a 3-fold decline in the average speed of motility, a 2-fold reduced mitochondrial membrane potential and a 1.5-2-fold decline in basal respiration. Despite the reduction in mitochondrial function, mitochondrial import protein Tim23 was elevated in patient cell lines. MELAS fibroblasts exhibited increased MnSOD levels and lysosomal function when compared to healthy controls. Treatment of MELAS fibroblasts with rapamycin for 24 hrs resulted in increased mitochondrial respiration compared to control cells, a higher lysosome content, and a greater localization of mitochondria to lysosomes. Our studies suggest that rapamycin has the potential to improve cellular health even in the presence of mtDNA defects, primarily via an increase in lysosomal content.

scholarly journals Electron transport chain biogenesis activated by a JNK-insulin-Myc relay primes mitochondrial inheritance in Drosophila

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Zong-Heng Wang ◽  
Yi Liu ◽  
Vijender Chaitankar ◽  
Mehdi Pirooznia ◽  
Hong Xu
Keyword(s):  
Electron Transport ◽  
Mitochondrial Biogenesis ◽  
Mitochondrial Respiration ◽  
Electron Transport Chain ◽  
Mtdna Copy Number ◽  
Cellular Mechanisms ◽  
Dynamic Regulation ◽  
Mtdna Mutations ◽  
Transport Chain ◽  
Mtdna Replication

Oogenesis features an enormous increase in mitochondrial mass and mtDNA copy number, which are required to furnish mature eggs with an adequate supply of mitochondria and to curb the transmission of deleterious mtDNA variants. Quiescent in dividing germ cells, mtDNA replication initiates upon oocyte determination in the Drosophila ovary, which necessitates active mitochondrial respiration. However, the underlying mechanism for this dynamic regulation remains unclear. Here, we show that an feedforward insulin-Myc loop promotes mitochondrial respiration and biogenesis by boosting the expression of electron transport chain subunits and of factors essential for mtDNA replication and expression, and for the import of mitochondrial proteins. We further reveal that transient activation of JNK enhances the expression of the insulin receptor and initiates the insulin-Myc signaling loop. This signaling relay promotes mitochondrial biogenesis in the ovary, and thereby plays a role in limiting the transmission of deleterious mtDNA mutations. Our study demonstrates cellular mechanisms that couple mitochondrial biogenesis and inheritance with oocyte development.

scholarly journals Do Autophagy Enhancers/ROS Scavengers Alleviate Consequences of Mild Mitochondrial Dysfunction Induced in Neuronal-Derived Cells?

2021 ◽  
Vol 22 (11) ◽  
pp. 5753
Author(s):  
Damri Odeya ◽  
Natour Sarya ◽  
Agam Galila
Keyword(s):  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Mitochondrial Respiration ◽  
Consumption Rate ◽  
Ros Scavenging ◽  
Positive Effects ◽  
Mtdna Mutations ◽  
Human Neuronal Cells ◽  
Ros Scavengers ◽  
Cellular Resilience

Mitochondrial function is at the nexus of pathways regulating synaptic-plasticity and cellular resilience. The involvement of brain mitochondrial dysfunction along with increased reactive oxygen species (ROS) levels, accumulating mtDNA mutations, and attenuated autophagy is implicated in psychiatric and neurodegenerative diseases. We have previously modeled mild mitochondrial dysfunction assumed to occur in bipolar disorder (BPD) using exposure of human neuronal cells (SH-SY5Y) to rotenone (an inhibitor of mitochondrial-respiration complex-I) for 72 and 96 h, which exhibited up- and down-regulation of mitochondrial respiration, respectively. In this study, we aimed to find out whether autophagy enhancers (lithium, trehalose, rapamycin, and resveratrol) and/or ROS scavengers [resveratrol, N-acetylcysteine (NAC), and Mn-Tbap) can ameliorate neuronal mild mitochondrial dysfunction. Only lithium (added for the last 24/48 h of the exposure to rotenone for 72/96 h, respectively) counteracted the effect of rotenone on most of the mitochondrial respiration parameters (measured as oxygen consumption rate (OCR)). Rapamycin, resveratrol, NAC, and Mn-Tbap counteracted most of rotenone’s effects on OCR parameters after 72 h, possibly via different mechanisms, which are not necessarily related to their ROS scavenging and/or autophagy enhancement effects. The effect of lithium reversing rotenone’s effect on OCR parameters is compatible with lithium’s known positive effects on mitochondrial function and is possibly mediated via its effect on autophagy. By-and-large it may be summarized that some autophagy enhancers/ROS scavengers alleviate some rotenone-induced mild mitochondrial changes in SH-SY5Y cells.

Cytotoxicity of Hydrazones of Morpholine Bearing Mannich Bases Towards Huh7 and T47D Cell Lines and Their Effects on Mitochondrial Respiration

2016 ◽  
Vol 13 (8) ◽  
pp. 734-741 ◽  
Author(s):  
Kaan Kucukoglu ◽  
Halise Inci Gul ◽  
Mustafa Gul ◽  
Rengul Cetin-Atalay ◽  
Yosra Baratli ◽  
...  
Keyword(s):  
Cell Lines ◽  
Mitochondrial Respiration ◽  
T47d Cell ◽  
Mannich Bases

scholarly journals Two Subpopulations of Human Monocytes That Differ by Mitochondrial Membrane Potential

Biomedicines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 153
Author(s):  
Nikita G. Nikiforov ◽  
Anastasia Ryabova ◽  
Marina V. Kubekina ◽  
Igor D. Romanishkin ◽  
Kirill A. Trofimov ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Primary Culture ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Function ◽  
Mitochondrial Membrane ◽  
Aminolevulinic Acid ◽  
Protoporphyrin Ix ◽  
Intima Media Thickness ◽  
Mtdna Mutations ◽  
Proinflammatory Activity

Atherosclerosis is associated with a chronic local inflammatory process in the arterial wall. Our previous studies have demonstrated the altered proinflammatory activity of circulating monocytes in patients with atherosclerosis. Moreover, atherosclerosis progression and monocyte proinflammatory activity were associated with mitochondrial DNA (mtDNA) mutations in circulating monocytes. The role of mitochondria in the immune system cells is currently well recognized. They can act as immunomodulators by releasing molecules associated with bacterial infection. We hypothesized that atherosclerosis can be associated with changes in the mitochondrial function of circulating monocytes. To test this hypothesis, we performed live staining of the mitochondria of CD14+ monocytes from healthy donors and atherosclerosis patients with MitoTracker Orange CMTMRos dye, which is sensitive to mitochondrial membrane potential. The intensity of such staining reflects mitochondrial functional activity. We found that parts of monocytes in the primary culture were characterized by low MitoTracker staining (MitoTracker-low monocytes). Such cells were morphologically similar to cells with normal staining and able to metabolize 5-aminolevulinic acid and accumulate the heme precursor protoporphyrin IX (PplX), indicative of partially preserved mitochondrial function. We assessed the proportion of MitoTracker-low monocytes in the primary culture for each study subject and compared the results with other parameters, such as monocyte ability to lipopolysaccharide (LPS)-induced proinflammatory activation and the intima-media thickness of carotid arteries. We found that the proportion of MitoTracker-low monocytes was associated with the presence of atherosclerotic plaques. An increased number of such monocytes in the primary culture was associated with a reduced proinflammatory activation ability of cells. The obtained results indicate the presence of circulating monocytes with mitochondrial dysfunction and the association of such cells with chronic inflammation and atherosclerosis development.

scholarly journals Transcriptional landscape of cellular networks reveal interactions driving the dormancy mechanisms in cancer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dilara Uzuner ◽  
Yunus Akkoç ◽  
Nesibe Peker ◽  
Pınar Pir ◽  
Devrim Gözüaçık ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Regulatory Networks ◽  
Metastatic Cancer ◽  
Interaction Network ◽  
Current Treatment ◽  
Cellular Mechanisms ◽  
Protein Protein Interaction ◽  
Cancer Dormancy ◽  
Protein Protein Interaction Networks ◽  
First Time

AbstractPrimary cancer cells exert unique capacity to disseminate and nestle in distant organs. Once seeded in secondary sites, cancer cells may enter a dormant state, becoming resistant to current treatment approaches, and they remain silent until they reactivate and cause overt metastases. To illuminate the complex mechanisms of cancer dormancy, 10 transcriptomic datasets from the literature enabling 21 dormancy–cancer comparisons were mapped on protein–protein interaction networks and gene-regulatory networks to extract subnetworks that are enriched in significantly deregulated genes. The genes appearing in the subnetworks and significantly upregulated in dormancy with respect to proliferative state were scored and filtered across all comparisons, leading to a dormancy–interaction network for the first time in the literature, which includes 139 genes and 1974 interactions. The dormancy interaction network will contribute to the elucidation of cellular mechanisms orchestrating cancer dormancy, paving the way for improvements in the diagnosis and treatment of metastatic cancer.

Abstract 131: Anti-inflammatory and Mitochondrial Effects of Butyrate in Shr Astrocytes in vitro

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Tao Yang ◽  
Ty Redler ◽  
Carla G Bueno Silva ◽  
Rebeca Arocha ◽  
Jordan Schmidt ◽  
...  
Keyword(s):  
Mitochondrial Function ◽  
Mitochondrial Respiration ◽  
Rna Isolation ◽  
Inflammatory Factors ◽  
Pcr Analysis ◽  
Sprague Dawley ◽  
Beneficial Effects ◽  
Sd Rats ◽  
Anti Inflammatory

Emerging evidence demonstrates a significant link between gut dysbiosis and hypertension (HTN). Butyrate is one of the major fermented end-products of gut microbiota that reportedly produces beneficial effects on the immune system and metabolism. A contraction in butyrate-producing bacteria in the gut of spontaneously hypertensive rats (SHR) suggests that reduced butyrate may be associated with HTN. Considering its role in mitochondrial metabolism, we proposed that the positive anti-inflammatory effects of butyrate may be mediated via improvement in mitochondrial function in astrocytes. Methods: Sprague Dawley (SD) and SHR primary astrocytes from two-day old pups were cultured in DMEM, supplemented with 10% FBS and 1% pen/strep, for 14 days, prior to treatment with butyrate (0-1mM) for 4 hours. Cells were then subjected to the Seahorse XFe24 Extracellular Flux Analyzer to evaluate mitochondrial function following butyrate treatment. Additional samples were collected for total RNA isolation for real time PCR analysis of inflammatory factors and transcripts related to mitochondrial function and stress. Results: Butyrate significantly increased both basal and maximal mitochondrial respiration (by 3-4 fold, P<0.001) and elevated proton leak (by 4 fold, P<0.01) in astrocytes from SD rats but not SHR. Furthermore, we observed a trend for an increase in both ATP-linked and non-mitochondrial respiration in SD astrocytes compared to SHR (by 2-3 fold, P=0.07). This was associated with a significant reduction in relative expression levels in catalase (by 50%, P<0.05) and a trend in reduction in Sod1 and Sod2 (by 25%-50%, P=0.1) in astrocytes harvested from SD rats but not the SHR. Conversely, butyrate significantly lowered expression of pro-inflammatory Ccl2 (by 33%, P<0.05) and Tlr4 (by 48%, P <0.05) in astrocytes of SHR, but not SD rats. Conclusion: Butyrate modulated mitochondrial bioenergetics in SD but not the SHR, suggesting that the mitochondria of astrocytes may be less sensitive to the effects of butyrate in HTN. In addition, butyrate reduced inflammatory mediators in the SHR, but had no effect in the SD rat astrocytes. Thus, central anti-inflammatory effects of butyrate may be mediated via a mitochondria-independent mechanism.

scholarly journals Mitochondrial nucleoids maintain genetic autonomy but allow for functional complementation

2008 ◽  
Vol 181 (7) ◽  
pp. 1117-1128 ◽  
Author(s):  
Robert W. Gilkerson ◽  
Eric A. Schon ◽  
Evelyn Hernandez ◽  
Mercy M. Davidson
Keyword(s):  
Mitochondrial Dna ◽  
Protein Synthesis ◽  
Molecular Mechanism ◽  
Cell Lines ◽  
Mitochondrial Protein ◽  
Functional Complementation ◽  
Mitochondrial Protein Synthesis ◽  
Protein Assemblies ◽  
Mtdna Mutations ◽  
Mitochondrial Nucleoids

Mitochondrial DNA (mtDNA) is packaged into DNA-protein assemblies called nucleoids, but the mode of mtDNA propagation via the nucleoid remains controversial. Two mechanisms have been proposed: nucleoids may consistently maintain their mtDNA content faithfully, or nucleoids may exchange mtDNAs dynamically. To test these models directly, two cell lines were fused, each homoplasmic for a partially deleted mtDNA in which the deletions were nonoverlapping and each deficient in mitochondrial protein synthesis, thus allowing the first unequivocal visualization of two mtDNAs at the nucleoid level. The two mtDNAs transcomplemented to restore mitochondrial protein synthesis but were consistently maintained in discrete nucleoids that did not intermix stably. These results indicate that mitochondrial nucleoids tightly regulate their genetic content rather than freely exchanging mtDNAs. This genetic autonomy provides a molecular mechanism to explain patterns of mitochondrial genetic inheritance, in addition to facilitating therapeutic methods to eliminate deleterious mtDNA mutations.

scholarly journals Plasticity of non-shivering thermogenesis and brown adipose tissue in high-altitude deer mice

2021 ◽  
Author(s):  
Soren Z. Coulson ◽  
Cayleih E. Robertson ◽  
Sajeni Mahalingam ◽  
Grant B. McClelland
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
High Altitude ◽  
Heat Production ◽  
Mitochondrial Function ◽  
Mitochondrial Respiration ◽  
Deer Mice ◽  
Brown Adipose ◽  
Hypoxia Acclimation ◽  
Shivering Thermogenesis

High altitude environments challenge small mammals with persistent low ambient temperatures that require high rates of aerobic heat production in face of low O2 availability. An important component of thermogenic capacity in rodents is non-shivering thermogenesis (NST) mediated by uncoupled mitochondrial respiration in brown adipose tissue (BAT). NST is plastic, and capacity for heat production increases with cold acclimation. However, in lowland native rodents, hypoxia inhibits NST in BAT. We hypothesize that highland deer mice (Peromyscus maniculatus) overcome the hypoxic inhibition of NST through changes in BAT mitochondrial function. We tested this hypothesis using lab born and raised highland and lowland deer mice, and a lowland congeneric (P. leucopus), acclimated to either warm normoxia (25°C, 760 mmHg) or cold hypoxia (5°C, 430 mmHg). We determined the effects of acclimation and ancestry on whole-animal rates of NST, the mass of interscapular BAT (iBAT), and uncoupling protein (UCP)-1 protein expression. To identify changes in mitochondrial function, we conducted high-resolution respirometry on isolated iBAT mitochondria using substrates and inhibitors targeted to UCP-1. We found that rates of NST increased with cold hypoxia acclimation but only in highland deer mice. There was no effect of cold hypoxia acclimation on iBAT mass in any group, but highland deer mice showed increases in UCP-1 expression and UCP-1 stimulated mitochondrial respiration in response to these stressors. Our results suggest that highland deer mice have evolved to increase the capacity for NST in response to chronic cold hypoxia, driven in part by changes in iBAT mitochondrial function.

scholarly journals Creation of Cybrid Cultures Containing mtDNA Mutations m.12315G>A and m.1555G>A, Associated with Atherosclerosis

Biomolecules ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 499 ◽  
Author(s):  
Margarita A. Sazonova ◽  
Vasily V. Sinyov ◽  
Anastasia I. Ryzhkova ◽  
Marina D. Sazonova ◽  
Zukhra B. Khasanova ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Drug Therapy ◽  
Mitochondrial Genome ◽  
Cell Lines ◽  
Threshold Value ◽  
Mtdna Mutation ◽  
Single Nucleotide ◽  
Mtdna Mutations ◽  
Cybrid Cell ◽  
In Cells

In the present work, a pilot creation of four cybrid cultures with high heteroplasmy level was performed using mitochondrial genome mutations m.12315G>A and m.1555G>A. According to data of our preliminary studies, the threshold heteroplasmy level of mutation m.12315G>A is associated with atherosclerosis. At the same time, for a mutation m.1555G>A, such a heteroplasmy level is associated with the absence of atherosclerosis. Cybrid cultures were created by fusion of rho0-cells and mitochondria from platelets with a high heteroplasmy level of the investigated mutations. To create rho0-cells, THP-1 culture of monocytic origin was taken. According to the results of the study, two cybrid cell lines containing mutation m.12315G>A with the heteroplasmy level above the threshold value (25% and 44%, respectively) were obtained. In addition, two cybrid cell lines containing mutation m.1555G>A with a high heteroplasmy level (24%) were obtained. Cybrid cultures with mtDNA mutation m.12315G>A can be used to model both the occurrence and development of atherosclerosis in cells and the titration of drug therapy for patients with atherosclerosis. With the help of cybrid cultures containing single nucleotide replacement of mitochondrial genome m.1555G>A, it is possible to develop approaches to the gene therapy of atherosclerosis.

Sign in / Sign up

Export Citation Format

Share Document