Impact of endurance training on murine spontaneous activity, muscle mitochondrial DNA abundance, gene transcripts, and function

2007 ◽  
Vol 102 (3) ◽  
pp. 1078-1089 ◽  
Author(s):  
Lisa S. Chow ◽  
Laura J. Greenlund ◽  
Yan W. Asmann ◽  
Kevin R. Short ◽  
Shelly K. McCrady ◽  
...  

We hypothesized that enhanced skeletal muscle mitochondrial function following aerobic exercise training is related to an increase in mitochondrial transcription factors, DNA abundance [mitochondrial DNA (mtDNA)], and mitochondria-related gene transcript levels, as well as spontaneous physical activity (SPA) levels. We report the effects of daily treadmill training on 12-wk-old FVB mice for 5 days/wk over 8 wk at 80% peak O2 consumption and studied the training effect on changes in body composition, glucose tolerance, muscle mtDNA muscle, mitochondria-related gene transcripts, in vitro muscle mitochondrial ATP production capacity (MATPC), and SPA levels. Compared with the untrained mice, the trained mice had higher peak O2 consumption (+18%; P < 0.001), lower percentage of abdominal (−25.4%; P < 0.02) and body fat (−19.5%; P < 0.01), improved glucose tolerance ( P < 0.04), and higher muscle mitochondrial enzyme activity (+19.5–43.8%; P < 0.04) and MATPC (+28.9 to +32.4%; P < 0.01). Gene array analysis showed significant differences in mRNAs of mitochondria-related ontology groups between the trained and untrained mice. Training also increased muscle mtDNA (+88.4 to +110%; P < 0.05), peroxisome proliferative-activated receptor-γ coactivator-1α protein (+99.5%; P < 0.04), and mitochondrial transcription factor A mRNA levels (+21.7%; P < 0.004) levels. SPA levels were higher in trained mice ( P = 0.056, two-sided t-test) and significantly correlated with two separate substrate-based measurements of MATPC ( P < 0.02). In conclusion, aerobic exercise training enhances muscle mitochondrial transcription factors, mtDNA abundance, mitochondria-related gene transcript levels, and mitochondrial function, and this enhancement in mitochondrial function occurs in association with increased SPA.

2006 ◽  
Vol 291 (4) ◽  
pp. H1722-H1730 ◽  
Author(s):  
Sabzali Javadov ◽  
Daniel M. Purdham ◽  
Asad Zeidan ◽  
Morris Karmazyn

We have recently demonstrated that mitochondrial respiratory dysfunction and mitochondrial permeability transition pore opening during postinfarction remodeling are prevented by the Na+/H+ exchange-1 (NHE-1)-specific inhibitor EMD-87580 (EMD). One of the mechanisms underlying the beneficial effect of NHE-1 inhibition on mitochondria could result from the drug's ability to regulate transcriptional factors responsible for mitochondrial function. In the present study, the effect of EMD on the expression of nuclear factors involved in mitochondrial biogenesis and expression of nuclear (COXNUCSUB IV) and mitochondrial (COXMITSUB I) encoded cytochrome c oxidase subunits has been studied in rat hearts subjected to either 12 or 18 wk of coronary artery ligation (CAL). Remodeling induced an increase in expression of the hypertrophic marker gene atrial natriuretic peptide, especially 12 wk after CAL. The mRNA level of the peroxisome proliferator-activated receptor-γ coactivator-1α and its downstream factors, including nuclear respiratory factor 1 and 2, mitochondrial transcription factor A, COXNUCSUB IV, and COXMITSUB I, were significantly reduced in hearts both 12 and 18 wk after ligation compared with sham-operated hearts. Dietary EMD provided immediately after ligation attenuated downregulation of mitochondrial transcription factors with a parallel decrease of hypertrophic marker gene expression. Regression analysis demonstrated a strong positive correlation between the transcription factors and mitochondrial respiratory function. Thus our study shows that the downregulation of mitochondrial transcription factors induced by postinfarction remodeling can be significantly attenuated by NHE-1 inhibition with a further improvement of mitochondrial function in these hearts.


2019 ◽  
Author(s):  
Bhargavi Natarajan ◽  
Vikas Arige ◽  
Abrar A. Khan ◽  
S. Santosh Reddy ◽  
Rashmi Santhoshkumar ◽  
...  

AbstractKidneys have a high resting metabolic rate and low tissue partial pressure of oxygen due to enhanced mitochondrial oxygen consumption and ATP production for active solute transport. Enhanced mitochondrial activity leads to progressive hypoxia from the renal cortex to renal medulla. Renal tubulointerstitial hypoxia (TiH) is severe in hypertensive rats due to increased sodium reabsorption within their nephrons. Additionally, these rats display increased energy demand and therefore, require healthy mitochondria for adequate salt reabsorption. Hence, we sought to study the regulation of mitochondrial biogenesis and expression of mitochondrial transcription factors (mtTFs, viz. Tfam, Tfb1m and Tfb2m) during hypoxic conditions and in rodent models of genetic hypertension. We report that the expressions of HIF-1α (hypoxia inducible factor-1α), PGC-1α (peroxisome proliferator activated receptor-γ co-activator-1α), mtTFs and OXPHOS proteins are elevated in hypertensive rats as compared to their normotensive counterparts. Additionally, studies in cultured kidney cells show that acute hypoxia augments the expression of these genes. We also observe a positive correlation between HIF-1α and mtTFs transcripts in human tissues. Furthermore, we report for the first time to our knowledge, that HIF-1α binds to promoters of Tfam, Tfb1m and Tfb2m genes and augments their promoter activities in NRK52e cells subjected to acute hypoxia. Taken together, this study suggests that acute hypoxia may enhance mitochondrial function to meet the energy demand in renal tubular epithelial cells and in young/pre-hypertensive SHR kidneys.Translational StatementOur results suggest that tubulointerstitial hypoxia (TiH) prevailing in prehypertensive rats augments the expression of mitochondrial transcription factors and proteins of electron transport chain. Moreover, previous reports indicate that ATP synthesis in these rats are elevated. Thus, our study provides insights into the molecular mechanism of such enhanced mitochondrial function. We propose that during early stages of kidney diseases (marked by mild TiH) an enhancement of mitochondrial function via stimulation of HIF-1α/PGC-1α production may delay renal tubular damage.


2020 ◽  
Vol 70 (12) ◽  
pp. 4244-4247

Leber hereditary optical neuropathy (LHON) is part of the class of optic neuropathies in which the mitochondrial function is impaired and is characterized by a painless, subacute, bilateral decrease of the central vision. We shall present the case of two brothers AM aged 31 and AT aged 40 who were diagnosed with LHON and whom we initiated treatment with idebenone 900 mg / day with monitoring at one month and 6 months. The mitochondrial DNA analysis demonstrated the existence of mutations 11778G>A for the mtND4 gene in both patients. Idebenone is a synthetic benzoquinone, analogue of ubiquinone. We found a slight but significant improvement in the visual field in patient AM at one month of treatment. We have not found another case in the literature with an improvement in vision so fast after this treatment, and this has led us to write this article. Keywords: Leber hereditary optical neuropathy (LHON), idebenone, mutations 11778G>A, mtND4 gene


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sara Lago ◽  
Matteo Nadai ◽  
Filippo M. Cernilogar ◽  
Maryam Kazerani ◽  
Helena Domíniguez Moreno ◽  
...  

AbstractCell identity is maintained by activation of cell-specific gene programs, regulated by epigenetic marks, transcription factors and chromatin organization. DNA G-quadruplex (G4)-folded regions in cells were reported to be associated with either increased or decreased transcriptional activity. By G4-ChIP-seq/RNA-seq analysis on liposarcoma cells we confirmed that G4s in promoters are invariably associated with high transcription levels in open chromatin. Comparing G4 presence, location and transcript levels in liposarcoma cells to available data on keratinocytes, we showed that the same promoter sequences of the same genes in the two cell lines had different G4-folding state: high transcript levels consistently associated with G4-folding. Transcription factors AP-1 and SP1, whose binding sites were the most significantly represented in G4-folded sequences, coimmunoprecipitated with their G4-folded promoters. Thus, G4s and their associated transcription factors cooperate to determine cell-specific transcriptional programs, making G4s to strongly emerge as new epigenetic regulators of the transcription machinery.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 90
Author(s):  
Lorenzo Rivas-García ◽  
José Luis Quiles ◽  
Alfonso Varela-López ◽  
Francesca Giampieri ◽  
Maurizio Battino ◽  
...  

The application of metallic nanoparticles (materials with size at least in one dimension ranging from 1 to 100 nm) as a new therapeutic tool will improve the diagnosis and treatment of diseases. The mitochondria could be a therapeutic target to treat pathologies whose origin lies in mitochondrial dysfunctions or whose progression is dependent on mitochondrial function. We aimed to study the subcellular distribution of 2–4 nm iron nanoparticles and its effect on mitochondrial DNA (mtDNA), mitochondrial function, and autophagy in colorectal cell lines (HT-29). Results showed that when cells were exposed to ultra-small iron nanoparticles, their subcellular fate was mainly mitochondria, affecting its respiratory and glycolytic parameters, inducing the migration of the cellular state towards quiescence, and promoting and triggering the autophagic process. These effects support the potential use of nanoparticles as therapeutic agents using mitochondria as a target for cancer and other treatments for mitochondria-dependent pathologies.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Keita Matsuoka ◽  
Ryosuke Sato ◽  
Yuki Matsukura ◽  
Yoshiki Kawajiri ◽  
Hiromi Iino ◽  
...  

AbstractANAC071 and its homolog ANAC096 are plant-specific transcription factors required for the initiation of cell division during wound healing in incised Arabidopsis flowering stems and Arabidopsis hypocotyl grafts; however, the mechanism remains mostly unknown. In this study, we showed that wound-induced cambium formation involved cell proliferation and the promoter activity of TDR/PXY (cambium-related gene) in the incised stem. Prior to the wound-induced cambium formation, both ANAC071 and ANAC096 were expressed at these sites. anac-multiple mutants significantly decreased wound-induced cambium formation in the incised stems and suppressed the conversion from mesophyll cells to cambial cells in an ectopic vascular cell induction culture system (VISUAL). Our results suggest that ANAC071 and ANAC096 are redundantly involved in the process of “cambialization”, the conversion from differentiated cells to cambial cells, and these cambium-like cells proliferate and provide cells in wound tissue during the tissue-reunion process.


Author(s):  
George B. Stefano ◽  
Richard M. Kream

AbstractMitochondrial DNA (mtDNA) heteroplasmy is the dynamically determined co-expression of wild type (WT) inherited polymorphisms and collective time-dependent somatic mutations within individual mtDNA genomes. The temporal expression and distribution of cell-specific and tissue-specific mtDNA heteroplasmy in healthy individuals may be functionally associated with intracellular mitochondrial signaling pathways and nuclear DNA gene expression. The maintenance of endogenously regulated tissue-specific copy numbers of heteroplasmic mtDNA may represent a sensitive biomarker of homeostasis of mitochondrial dynamics, metabolic integrity, and immune competence. Myeloid cells, monocytes, macrophages, and antigen-presenting dendritic cells undergo programmed changes in mitochondrial metabolism according to innate and adaptive immunological processes. In the central nervous system (CNS), the polarization of activated microglial cells is dependent on strategically programmed changes in mitochondrial function. Therefore, variations in heteroplasmic mtDNA copy numbers may have functional consequences in metabolically competent mitochondria in innate and adaptive immune processes involving the CNS. Recently, altered mitochondrial function has been demonstrated in the progression of coronavirus disease 2019 (COVID-19) due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Accordingly, our review is organized to present convergent lines of empirical evidence that potentially link expression of mtDNA heteroplasmy by functionally interactive CNS cell types to the extent and severity of acute and chronic post-COVID-19 neurological disorders.


Biomedicines ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 76 ◽  
Author(s):  
Suresh P. Khadke ◽  
Aniket A. Kuvalekar ◽  
Abhay M. Harsulkar ◽  
Nitin Mantri

Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by impaired insulin action and its secretion. The objectives of the present study were to establish an economical and efficient animal model, mimicking pathophysiology of human T2DM to understand probable molecular mechanisms in context with lipid metabolism. In the present study, male Wistar rats were randomly divided into three groups. Animals were fed with high fat diet (HFD) except healthy control (HC) for 12 weeks. After eight weeks, intra peritoneal glucose tolerance test was performed. After confirmation of glucose intolerance, diabetic control (DC) group was injected with streptozotocin (STZ) (35 mg/kg b.w., i.p.). HFD fed rats showed increase (p ≤ 0.001) in glucose tolerance and HOMA-IR as compared to HC. Diabetes rats showed abnormal (p ≤ 0.001) lipid profile as compared to HC. The hepatocyte expression of transcription factors SREBP-1c and NFκβ, and their target genes were found to be upregulated, while PPAR-γ, CPT1A and FABP expressions were downregulated as compared to the HC. A number of animal models have been raised for studying T2DM, but the study has been restricted to only the biochemical level. The model is validated at biochemical, molecular and histopathological levels, which can be used for screening new therapeutics for the effective management of T2DM.


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