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Walsh DJ, Bernard DJ, Fiddler JL, Pangilinan F, Esposito M, Harold D, Field MS, Parle-McDermott A, Brody LC. Vitamin B12 status and folic acid supplementation influence mitochondrial heteroplasmy levels in mice. PNAS NEXUS 2024; 3:pgae116. [PMID: 38560530 PMCID: PMC10978065 DOI: 10.1093/pnasnexus/pgae116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 02/29/2024] [Indexed: 04/04/2024]
Abstract
One-carbon metabolism is a complex network of metabolic reactions that are essential for cellular function including DNA synthesis. Vitamin B12 and folate are micronutrients that are utilized in this pathway and their deficiency can result in the perturbation of one-carbon metabolism and subsequent perturbations in DNA replication and repair. This effect has been well characterized in nuclear DNA but to date, mitochondrial DNA (mtDNA) has not been investigated extensively. Mitochondrial variants have been associated with several inherited and age-related disease states; therefore, the study of factors that impact heteroplasmy are important for advancing our understanding of the mitochondrial genome's impact on human health. Heteroplasmy studies require robust and efficient mitochondrial DNA enrichment to carry out in-depth mtDNA sequencing. Many of the current methods for mtDNA enrichment can introduce biases and false-positive results. Here, we use a method that overcomes these limitations and have applied it to assess mitochondrial heteroplasmy in mouse models of altered one-carbon metabolism. Vitamin B12 deficiency was found to cause increased levels of mitochondrial DNA heteroplasmy across all tissues that were investigated. Folic acid supplementation also contributed to elevated mitochondrial DNA heteroplasmy across all mouse tissues investigated. Heteroplasmy analysis of human data from the Framingham Heart Study suggested a potential sex-specific effect of folate and vitamin B12 status on mitochondrial heteroplasmy. This is a novel relationship that may have broader consequences for our understanding of one-carbon metabolism, mitochondrial-related disease and the influence of nutrients on DNA mutation rates.
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Affiliation(s)
- Darren J Walsh
- Gene and Environment Interaction Section, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
- School of Biotechnology, Dublin City University, Dublin 9, Ireland
| | - David J Bernard
- Gene and Environment Interaction Section, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Joanna L Fiddler
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14850, USA
- Department of Food, Nutrition, and Packaging Sciences, Clemson University, Clemson, SC 29634, USA
| | - Faith Pangilinan
- Gene and Environment Interaction Section, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Madison Esposito
- Gene and Environment Interaction Section, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Denise Harold
- School of Biotechnology, Dublin City University, Dublin 9, Ireland
| | - Martha S Field
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14850, USA
| | | | - Lawrence C Brody
- Gene and Environment Interaction Section, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
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Bayazit MB, Francois A, McGrail E, Accornero F, Stratton MS. mt-tRNAs in the polymerase gamma mutant heart. THE JOURNAL OF CARDIOVASCULAR AGING 2023; 3:41. [PMID: 38235059 PMCID: PMC10793997 DOI: 10.20517/jca.2023.26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Introduction Mice harboring a D257A mutation in the proofreading domain of the mitochondrial DNA polymerase, Polymerase Gamma (POLG), experience severe metabolic dysfunction and display hallmarks of accelerated aging. We previously reported a mitochondrial unfolded protein response (UPTmt) - like (UPRmt-like) gene and protein expression pattern in the right ventricular tissue of POLG mutant mice. Aim We sought to determine if POLG mutation altered the expression of genes encoded by the mitochondria in a way that might also reduce proteotoxic stress. Methods and Results The expression of genes encoded by the mitochondrial DNA was interrogated via RNA-seq and northern blot analysis. A striking, location-dependent effect was seen in the expression of mitochondrial-encoded tRNAs in the POLG mutant as assayed by RNA-seq. These expression changes were negatively correlated with the tRNA partner amino acid's amyloidogenic potential. Direct measurement by northern blot was conducted on candidate mt-tRNAs identified from the RNA-seq. This analysis confirmed reduced expression of MT-TY in the POLG mutant but failed to show increased expression of MT-TP, which was dramatically increased in the RNA-seq data. Conclusion We conclude that reduced expression of amyloid-associated mt-tRNAs is another indication of adaptive response to severe mitochondrial dysfunction in the POLG mutant. Incongruence between RNA-seq and northern blot measurement of MT-TP expression points towards the existence of mt-tRNA post-transcriptional modification regulation in the POLG mutant that alters either polyA capture or cDNA synthesis in RNA-seq library generation. Together, these data suggest that 1) evolution has distributed mt-tRNAs across the circular mitochondrial genome to allow chromosomal location-dependent mt-tRNA regulation (either by expression or PTM) and 2) this regulation is cognizant of the tRNA partner amino acid's amyloidogenic properties.
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Affiliation(s)
- M. Bilal Bayazit
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Ashley Francois
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Erin McGrail
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Federica Accornero
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Matthew S. Stratton
- Department of Physiology & Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
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Mito-SiPE is a sequence-independent and PCR-free mtDNA enrichment method for accurate ultra-deep mitochondrial sequencing. Commun Biol 2022; 5:1269. [PMID: 36402890 PMCID: PMC9675811 DOI: 10.1038/s42003-022-04182-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 10/27/2022] [Indexed: 11/21/2022] Open
Abstract
The analysis of somatic variation in the mitochondrial genome requires deep sequencing of mitochondrial DNA. This is ordinarily achieved by selective enrichment methods, such as PCR amplification or probe hybridization. These methods can introduce bias and are prone to contamination by nuclear-mitochondrial sequences (NUMTs), elements that can introduce artefacts into heteroplasmy analysis. We isolated intact mitochondria using differential centrifugation and alkaline lysis and subjected purified mitochondrial DNA to a sequence-independent and PCR-free method to obtain ultra-deep (>80,000X) sequencing coverage of the mitochondrial genome. This methodology avoids false-heteroplasmy calls that occur when long-range PCR amplification is used for mitochondrial DNA enrichment. Previously published methods employing mitochondrial DNA purification did not measure mitochondrial DNA enrichment or utilise high coverage short-read sequencing. Here, we describe a protocol that yields mitochondrial DNA and have quantified the increased level of mitochondrial DNA post-enrichment in 7 different mouse tissues. This method will enable researchers to identify changes in low frequency heteroplasmy without introducing PCR biases or NUMT contamination that are incorrectly identified as heteroplasmy when long-range PCR is used.
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Reply to 'Blood pressure regulation is multifactorial in mitochondrial disorders'. J Hypertens 2022; 40:2082. [PMID: 36052530 DOI: 10.1097/hjh.0000000000003203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Gorr MW, Francois A, Marcho LM, Saldana T, McGrail E, Sun N, Stratton MS. Molecular signature of cardiac remodeling associated with Polymerase Gamma mutation. Life Sci 2022; 298:120469. [PMID: 35283176 PMCID: PMC9158136 DOI: 10.1016/j.lfs.2022.120469] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/02/2022] [Accepted: 03/06/2022] [Indexed: 11/28/2022]
Abstract
AIMS Metabolic function/dysfunction is central to aging biology. This is well illustrated by the Polymerase Gamma (POLG) mutant mouse where a key residue of the mitochondrial DNA polymerase is mutated (D257A), causing loss of mitochondrial DNA stability and dramatically accelerated aging processes. Given known cardiac phenotypes in the POLG mutant, we sought to characterize the course of cardiac dysfunction in the POLG mutant to guide future intervention studies. MATERIALS AND METHODS Cardiac echocardiography and terminal hemodynamic analyses were used to define the course of dysfunction in the right and left cardiac ventricles in the POLG mutant. We also conducted RNA-seq analysis on cardiac right ventricles to identify mechanisms engaged by severe metabolic dysfunction and compared this analysis to several publically available datasets. KEY FINDINGS Interesting sex differences were noted as female POLG mutants died earlier than male POLG mutants and LV chamber diameters were impacted earlier in females than males. Moreover, male mutants showed LV wall thinning while female mutant LV walls were thicker. Both males and females displayed significant RV hypertrophy. POLG mutants displayed a gene expression pattern associated with inflammation, fibrosis, and heart failure. Finally, comparative omics analyses of publically available data provide additional mechanistic and therapeutic insights. SIGNIFICANCE Aging-associated cardiac dysfunction is a growing clinical problem. This work uncovers sex-specific cardiac responses to severe metabolic dysfunction that are reminiscent of patterns seen in human heart failure and provides insights to the molecular mechanisms engaged downstream of severe metabolic dysfunction that warrant further investigation.
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Affiliation(s)
- Matthew W. Gorr
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA,College of Nursing, The Ohio State University, Columbus, OH, USA
| | - Ashley Francois
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Lynn M. Marcho
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Ty Saldana
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Erin McGrail
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Nuo Sun
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Matthew S. Stratton
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
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Abstract
BACKGROUND Previous research suggests that hypertension is more prevalent among patients with mitochondrial diseases. Blood pressure (BP) is linearly related to increased cardiovascular risk, and this relationship is strongest for SBP; nevertheless, studies on SBP and DBP in mitochondrial diseases have not yet been performed. METHOD In a retrospective case-control study design, BP in mitochondrial disease patients was compared with BP in a population cohort. Secondly, using multiple linear regression, we examined blood pressure differences in various genetic mitochondrial diseases. Lastly, we explored additional predictors of BP in a subgroup with the m.3243A>G variant. RESULTS Two hundred and eighty-six genetically confirmed mitochondrial disease patients were included. One hundred and eighty of these patients carried the m.3243A>G mitochondrial DNA variant. SBP was 9 mmHg higher in female mitochondrial disease patients than in the general female population (95% CI: 4.4-13.3 mmHg, P < 0.001), whereas male patients had similar BP compared with controls. BP was not significantly different in patients with m.8344A>G and m.8363G>A, a mtDNA deletion or a nuclear mutation compared with m.3243A>G patients. Higher SBP was a predictor for left ventricular hypertrophy in the m.3243A>G subgroup (P = 0.04). CONCLUSION Novel aspects of the role of mitochondrial dysfunction in blood pressure regulation are exposed in this study. Compared with the general population, female mitochondrial disease patients have a higher SBP. Left ventricular hypertrophy is more prevalent in patients with higher SBP. Clinicians should be aware of this to prevent hypertensive complications in mitochondrial disease patients.
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Shin J, Hong SG, Choi SY, Rath ME, Saredy J, Jovin DG, Sayoc J, Park HS, Eguchi S, Rizzo V, Scalia R, Wang H, Houser SR, Park JY. Flow-induced endothelial mitochondrial remodeling mitigates mitochondrial reactive oxygen species production and promotes mitochondrial DNA integrity in a p53-dependent manner. Redox Biol 2022; 50:102252. [PMID: 35121402 PMCID: PMC8818582 DOI: 10.1016/j.redox.2022.102252] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 01/25/2022] [Accepted: 01/26/2022] [Indexed: 12/12/2022] Open
Abstract
Tumor suppressor p53 plays a pivotal role in orchestrating mitochondrial remodeling by regulating their content, fusion/fission processes, and intracellular signaling molecules that are associated with mitophagy and apoptosis pathways. In order to determine a molecular mechanism underlying flow-mediated mitochondrial remodeling in endothelial cells, we examined, herein, the role of p53 on mitochondrial adaptations to physiological flow and its relevance to vascular function using endothelial cell-specific p53 deficient mice. We observed no changes in aerobic capacity, basal blood pressure, or endothelial mitochondrial phenotypes in the endothelial p53 mull animals. However, after 7 weeks of voluntary wheel running exercise, blood pressure reduction and endothelial mitochondrial remodeling (biogenesis, elongation, and mtDNA replication) were substantially blunted in endothelial p53 null animals compared to the wild-type, subjected to angiotensin II-induced hypertension. In addition, endothelial mtDNA lesions were significantly reduced following voluntary running exercise in wild-type mice, but not in the endothelial p53 null mice. Moreover, in vitro studies demonstrated that unidirectional laminar flow exposure significantly increased key putative regulators for mitochondrial remodeling and reduced mitochondrial reactive oxygen species generation and mtDNA damage in a p53-dependent manner. Mechanistically, unidirectional laminar flow instigated translocalization of p53 into the mitochondrial matrix where it binds to mitochondrial transcription factor A, TFAM, resulting in improving mtDNA integrity. Taken together, our findings suggest that p53 plays an integral role in mitochondrial remodeling under physiological flow condition and the flow-induced p53-TFAM axis may be a novel molecular intersection for enhancing mitochondrial homeostasis in endothelial cells.
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Emerging methods for and novel insights gained by absolute quantification of mitochondrial DNA copy number and its clinical applications. Pharmacol Ther 2021; 232:107995. [PMID: 34592204 DOI: 10.1016/j.pharmthera.2021.107995] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 08/26/2021] [Accepted: 09/01/2021] [Indexed: 02/07/2023]
Abstract
The past thirty years have seen a surge in interest in pathophysiological roles of mitochondria, and the accurate quantification of mitochondrial DNA copy number (mCN) in cells and tissue samples is a fundamental aspect of assessing changes in mitochondrial health and biogenesis. Quantification of mCN between studies is surprisingly variable due to a combination of physiological variability and diverse protocols being used to measure this endpoint. The advent of novel methods to quantify nucleic acids like digital polymerase chain reaction (dPCR) and high throughput sequencing offer the ability to measure absolute values of mCN. We conducted an in-depth survey of articles published between 1969 -- 2020 to create an overview of mCN values, to assess consensus values of tissue-specific mCN, and to evaluate consistency between methods of assessing mCN. We identify best practices for methods used to assess mCN, and we address the impact of using specific loci on the mitochondrial genome to determine mCN. Current data suggest that clinical measurement of mCN can provide diagnostic and prognostic value in a range of diseases and health conditions, with emphasis on cancer and cardiovascular disease, and the advent of means to measure absolute mCN should improve future clinical applications of mCN measurements.
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Kirkman DL, Robinson AT, Rossman MJ, Seals DR, Edwards DG. Mitochondrial contributions to vascular endothelial dysfunction, arterial stiffness, and cardiovascular diseases. Am J Physiol Heart Circ Physiol 2021; 320:H2080-H2100. [PMID: 33834868 PMCID: PMC8163660 DOI: 10.1152/ajpheart.00917.2020] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 03/12/2021] [Accepted: 04/05/2021] [Indexed: 12/11/2022]
Abstract
Cardiovascular disease (CVD) affects one in three adults and remains the leading cause of death in America. Advancing age is a major risk factor for CVD. Recent plateaus in CVD-related mortality rates in high-income countries after decades of decline highlight a critical need to identify novel therapeutic targets and strategies to mitigate and manage the risk of CVD development and progression. Vascular dysfunction, characterized by endothelial dysfunction and large elastic artery stiffening, is independently associated with an increased CVD risk and incidence and is therefore an attractive target for CVD prevention and management. Vascular mitochondria have emerged as an important player in maintaining vascular homeostasis. As such, age- and disease-related impairments in mitochondrial function contribute to vascular dysfunction and consequent increases in CVD risk. This review outlines the role of mitochondria in vascular function and discusses the ramifications of mitochondrial dysfunction on vascular health in the setting of age and disease. The adverse vascular consequences of increased mitochondrial-derived reactive oxygen species, impaired mitochondrial quality control, and defective mitochondrial calcium cycling are emphasized, in particular. Current evidence for both lifestyle and pharmaceutical mitochondrial-targeted strategies to improve vascular function is also presented.
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Affiliation(s)
- Danielle L Kirkman
- Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, Virginia
| | | | - Matthew J Rossman
- Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - Douglas R Seals
- Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - David G Edwards
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware
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Bryant AJ, Pham A, Gogoi H, Mitchell CR, Pais F, Jin L. The Third Man: DNA sensing as espionage in pulmonary vascular health and disease. Pulm Circ 2021; 11:2045894021996574. [PMID: 33738095 PMCID: PMC7934053 DOI: 10.1177/2045894021996574] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 02/01/2021] [Indexed: 01/01/2023] Open
Abstract
For as long as nucleic acids have been utilized to vertically and horizontally transfer genetic material, living organisms have had to develop methods of recognizing cytosolic DNA as either pathogenic (microbial invasion) or physiologic (mitosis and cellular proliferation). Derangement in key signaling molecules involved in these pathways of DNA sensing result in a family of diseases labeled interferonopathies. An interferonopathy, characterized by constitutive expression of type I interferons, ultimately manifests as severe autoimmune disease at a young age. Afflicted patients present with a constellation of immune-mediated conditions, including primary lung manifestations such as pulmonary fibrosis and pulmonary hypertension. The latter condition is especially interesting in light of the known role that DNA damage plays in a variety of types of inherited and induced pulmonary hypertension, with free DNA detection elevated in the circulation of affected individuals. While little is known regarding the role of cytosolic DNA sensing in development of pulmonary vascular disease, exciting new research in the related fields of immunology and oncology potentially sheds light on future areas of fruitful exploration. As such, the goal of this review is to summarize the state of the field of nucleic acid sensing, extrapolating common shared pathways that parallel our knowledge of pulmonary hypertension, in a molecular and cell-specific manner. Principles of DNA sensing related to known pulmonary injury inducing stimuli are also evaluated, in addition to potential therapeutic targets. Finally, future directions in pulmonary hypertension research and treatments will be briefly discussed.
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Affiliation(s)
- Andrew J. Bryant
- University of Florida College of Medicine, Department of Medicine, Gainesville, FL, USA
| | - Ann Pham
- University of Florida College of Medicine, Department of Medicine, Gainesville, FL, USA
| | - Himanshu Gogoi
- University of Florida College of Medicine, Department of Medicine, Gainesville, FL, USA
| | - Carly R. Mitchell
- University of Florida College of Medicine, Department of Medicine, Gainesville, FL, USA
| | - Faye Pais
- University of Florida College of Medicine, Department of Medicine, Gainesville, FL, USA
| | - Lei Jin
- University of Florida College of Medicine, Department of Medicine, Gainesville, FL, USA
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Abstract
Vascular calcification (VC) was defined as the ectopic deposition of calcium-phosphorus complexes on the blood vessel walls. It was a process involving multiple factors and mechanisms, covering the phenotype transition of vascular smooth muscle cells (VSMCs) and release of microvesicles. It was a common end-stage alteration of chronic diseases such as cardiovascular disease and chronic kidney disease. Increasing evidence indicates that mitochondria were involved in the development of VC. Mitochondria provided energy to cells, maintained the stability of cell functions, and participated in a variety of biological behavior. Oxidative stress, autophagy, apoptosis, and mitochondrial DNA (mtDNA) damage could affect the development of VSMCs calcification by alteration of mitochondrial function. This article reviewed the mechanism of calcification and the role of mitochondria in VC, aiming to raise a novel insight into drug development and clinical treatment.
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12
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Pauls AD, Sandhu V, Young D, Nevay DL, Yeung DF, Sirrs S, Tsang MY, Tsang TSM, Lehman A, Mezei MM, Poburko D. High rate of hypertension in patients with m.3243A>G MELAS mutations and POLG variants. Mitochondrion 2020; 53:194-202. [PMID: 32502631 DOI: 10.1016/j.mito.2020.05.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 05/22/2020] [Accepted: 05/26/2020] [Indexed: 12/14/2022]
Abstract
Animal studies suggest that decreased vascular mitochondrial DNA copy number can promote hypertension. We conducted a chart review of blood pressure and hemodynamics in patients with either mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS, n = 36) or individuals with variants in the mitochondrial DNA polymerase gamma (POLG, n = 26). The latter included both pathogenic variants and variants of unknown significance (VUS). Hypertension rates (MELAS 50%, POLG 50%) were elevated relative to Canadian norms in 20-39 (MELAS) and 40-59 (MELAS and POLG) years of age groups. Peripheral resistance was high in the hypertensive versus normotensive patients, potentially indicative of microvascular disease. Despite antihypertensive treatment, systolic blood pressure remained elevated in the POLG versus MELAS group. The risk of hypertension was not associated with MELAS heteroplasmy. Hypertension rates were not different between individuals with known pathogenic POLG variants and those with VUS, including common variants. Hypertension (HT) also did not differ between patients with POLG variants with (n = 17) and without chronic progressive external opthalmoplegia (n = 9) (CPEO). HT was associated with variants in all three functional domains of POLG. These findings suggest that both pathogenic variants and several VUS in the POLG gene may promote human hypertension and extend our past reports that increased risk of HT is associated with MELAS.
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Affiliation(s)
- Andrew D Pauls
- Biomedical Physiology & Kinesiology, Simon Fraser University, Burnaby, Canada
| | - Vikrant Sandhu
- Biomedical Physiology & Kinesiology, Simon Fraser University, Burnaby, Canada
| | - Dana Young
- Adult Metabolic Diseases Unit, Vancouver General Hospital, Vancouver, BC, Canada
| | - Dayna-Lynn Nevay
- Adult Metabolic Diseases Unit, Vancouver General Hospital, Vancouver, BC, Canada
| | - Darwin F Yeung
- Division of Cardiology, University of British Columbia, Vancouver, BC, Canada
| | - Sandra Sirrs
- Adult Metabolic Diseases Unit, Vancouver General Hospital, Vancouver, BC, Canada
| | - Michael Y Tsang
- Division of Cardiology, University of British Columbia, Vancouver, BC, Canada
| | - Teresa S M Tsang
- Division of Cardiology, University of British Columbia, Vancouver, BC, Canada
| | - Anna Lehman
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Michelle M Mezei
- Adult Metabolic Diseases Unit, Vancouver General Hospital, Vancouver, BC, Canada; Division of Neurology, University of British Columbia, Vancouver, BC, Canada
| | - Damon Poburko
- Biomedical Physiology & Kinesiology, Simon Fraser University, Burnaby, Canada; Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, BC, Canada.
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Schmuck EG, Hacker TA, Schreier DA, Chesler NC, Wang Z. Beneficial effects of mesenchymal stem cell delivery via a novel cardiac bioscaffold on right ventricles of pulmonary arterial hypertensive rats. Am J Physiol Heart Circ Physiol 2019; 316:H1005-H1013. [PMID: 30822119 DOI: 10.1152/ajpheart.00091.2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Right ventricular failure (RVF) is a common cause of death in patients suffering from pulmonary arterial hypertension (PAH). The current treatment for PAH only moderately improves symptoms, and RVF ultimately occurs. Therefore, it is necessary to develop new treatment strategies to protect against right ventricle (RV) maladaptation despite PAH progression. In this study, we hypothesize that local mesenchymal stem cell (MSC) delivery via a novel bioscaffold can improve RV function despite persistent PAH. To test our hypothesis, we induced PAH in adult rats with SU5416 and chronic hypoxia exposure; treated with rat MSCs delivered by intravenous injection, intramyocardial injection, or epicardial placement of a bioscaffold; and then examined treatment effectiveness by in vivo pressure-volume measurement, echocardiography, histology, and immunohistochemistry. Our results showed that compared with other treatment groups, only the MSC-seeded bioscaffold group resulted in RV functional improvement, including restored stroke volume, cardiac output, and improved stroke work. Diastolic function indicated by end-diastolic pressure-volume relationship was improved by the local MSC treatments or bioscaffold alone. Cardiomyocyte hypertrophy and RV fibrosis were both reduced, and von Willebrand factor expression was restored by the MSC-seeded bioscaffold treatment. Overall, our study suggests a potential new regenerative therapy to rescue the pressure-overload failing RV with persistent pulmonary vascular disease, which may improve quality of life and/or survival of PAH patients. NEW & NOTEWORTHY We explored the effects of mesenchymal stem cell-seeded bioscaffold on right ventricles (RVs) of rats with established pulmonary arterial hypertension (PAH). Some beneficial effects were observed despite persistent PAH, suggesting that this may be a new therapy for RV to improve quality of life and/or survival of PAH patients.
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Affiliation(s)
- Eric G Schmuck
- Department of Medicine, University of Wisconsin , Madison, Wisconsin
| | - Timothy A Hacker
- Department of Medicine, University of Wisconsin , Madison, Wisconsin
| | - David A Schreier
- Department of Biomedical Engineering, University of Wisconsin , Madison, Wisconsin
| | - Naomi C Chesler
- Department of Medicine, University of Wisconsin , Madison, Wisconsin.,Department of Biomedical Engineering, University of Wisconsin , Madison, Wisconsin
| | - Zhijie Wang
- Department of Biomedical Engineering, University of Wisconsin , Madison, Wisconsin.,Department of Mechanical Engineering, Colorado State University , Fort Collins, Colorado
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14
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Philip JL, Murphy TM, Schreier DA, Stevens S, Tabima DM, Albrecht M, Frump AL, Hacker TA, Lahm T, Chesler NC. Pulmonary vascular mechanical consequences of ischemic heart failure and implications for right ventricular function. Am J Physiol Heart Circ Physiol 2019; 316:H1167-H1177. [PMID: 30767670 DOI: 10.1152/ajpheart.00319.2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Left heart failure (LHF) is the most common cause of pulmonary hypertension, which confers an increase in morbidity and mortality in this context. Pulmonary vascular resistance has prognostic value in LHF, but otherwise the mechanical consequences of LHF for the pulmonary vasculature and right ventricle (RV) remain unknown. We sought to investigate mechanical mechanisms of pulmonary vascular and RV dysfunction in a rodent model of LHF to address the knowledge gaps in understanding disease pathophysiology. LHF was created using a left anterior descending artery ligation to cause myocardial infarction (MI) in mice. Sham animals underwent thoracotomy alone. Echocardiography demonstrated increased left ventricle (LV) volumes and decreased ejection fraction at 4 wk post-MI that did not normalize by 12 wk post-MI. Elevation of LV diastolic pressure and RV systolic pressure at 12 wk post-MI demonstrated pulmonary hypertension (PH) due to LHF. There was increased pulmonary arterial elastance and pulmonary vascular resistance associated with perivascular fibrosis without other remodeling. There was also RV contractile dysfunction with a 35% decrease in RV end-systolic elastance and 66% decrease in ventricular-vascular coupling. In this model of PH due to LHF with reduced ejection fraction, pulmonary fibrosis contributes to increased RV afterload, and loss of RV contractility contributes to RV dysfunction. These are key pathologic features of human PH secondary to LHF. In the future, novel therapeutic strategies aimed at preventing pulmonary vascular mechanical changes and RV dysfunction in the context of LHF can be tested using this model. NEW & NOTEWORTHY In this study, we investigate the mechanical consequences of left heart failure with reduced ejection fraction for the pulmonary vasculature and right ventricle. Using comprehensive functional analyses of the cardiopulmonary system in vivo and ex vivo, we demonstrate that pulmonary fibrosis contributes to increased RV afterload and loss of RV contractility contributes to RV dysfunction. Thus this model recapitulates key pathologic features of human pulmonary hypertension-left heart failure and offers a robust platform for future investigations.
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Affiliation(s)
- Jennifer L Philip
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering , Madison, Wisconsin.,Department of Surgery, University of Wisconsin-Madison , Madison, Wisconsin
| | - Thomas M Murphy
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering , Madison, Wisconsin
| | - David A Schreier
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering , Madison, Wisconsin
| | - Sydney Stevens
- Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Diana M Tabima
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering , Madison, Wisconsin
| | - Margie Albrecht
- Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Andrea L Frump
- Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Timothy A Hacker
- Department of Medicine, University of Wisconsin-Madison , Madison, Wisconsin
| | - Tim Lahm
- Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana.,Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana.,Richard L. Roudebush Veterans Affairs Medical Center , Indianapolis, Indiana
| | - Naomi C Chesler
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering , Madison, Wisconsin.,Department of Medicine, University of Wisconsin-Madison , Madison, Wisconsin
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15
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Tabima DM, Philip JL, Chesler NC. Right Ventricular-Pulmonary Vascular Interactions. Physiology (Bethesda) 2018; 32:346-356. [PMID: 28814495 DOI: 10.1152/physiol.00040.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 06/16/2017] [Accepted: 07/06/2017] [Indexed: 11/22/2022] Open
Abstract
Accurate and comprehensive evaluation of right ventricular (RV)-pulmonary vascular (PV) interactions is critical to the assessment of cardiopulmonary function, dysfunction, and failure. Here, we review methods of quantifying RV-PV interactions and experimental results from clinical trials as well as large- and small-animal models based on pressure-volume analysis. We conclude by outlining critical gaps in knowledge that should drive future studies.
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Affiliation(s)
- Diana M Tabima
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, Wisconsin; and
| | - Jennifer L Philip
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, Wisconsin; and.,Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin
| | - Naomi C Chesler
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, Wisconsin; and
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16
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Golob MJ, Massoudi D, Tabima DM, Johnston JL, Wolf GD, Hacker TA, Greenspan DS, Chesler NC. Cardiovascular function and structure are preserved despite induced ablation of BMP1-related proteinases. Cell Mol Bioeng 2018; 11:255-266. [PMID: 30123369 DOI: 10.1007/s12195-018-0534-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Introduction Bone morphogenetic protein 1 (BMP1) is part of an extracellular metalloproteinase family that biosynthetically processes procollagen molecules. BMP1- and tolloid-like (TLL1) proteinases mediate the cleavage of carboxyl peptides from procollagen molecules, which is a crucial step in fibrillar collagen synthesis. Ablating the genes that encode BMP1-related proteinases (Bmp1 and Tll1) post-natally results in brittle bones, periodontal defects, and thin skin in conditional knockout (BTKO) mice. Despite the importance of collagen to cardiovascular tissues and the adverse effects of Bmp1 and Tll1 ablation in other tissues, the impact of Bmp1 and Tll1 ablation on cardiovascular performance is unknown. Here, we investigated the role of Bmp1- and Tll1-ablation in cardiovascular tissues by examining ventricular and vascular structure and function in BTKO mice. Methods Ventricular and vascular structure and function were comprehensively quantified in BTKO mice (n=9) and in age- and sex-matched controls (n=9). Echocardiography, cardiac catheterization, and biaxial ex vivo arterial mechanical testing were performed to assess tissue function, and histological staining was used to measure collagen protein content. Results Bmp1- and Tll1-ablation resulted in maintained hemodynamics and cardiovascular function, preserved biaxial arterial compliance, and comparable ventricular and vascular collagen protein content. Conclusions Maintained ventricular and vascular structure and function despite post-natal ablation of Bmp1 and Tll1 suggests that there is an as-yet unidentified compensatory mechanism in cardiovascular tissues. In addition, these findings suggest that proteinases derived from Bmp1 and Tll1 post-natally have less of an impact on cardiovascular tissues compared to skeletal, periodontal, and dermal tissues.
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Affiliation(s)
- Mark J Golob
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, WI 53706 USA
| | - Dawiyat Massoudi
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53706 USA
| | - Diana M Tabima
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, WI 53706 USA
| | - James L Johnston
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, WI 53706 USA
| | - Gregory D Wolf
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, WI 53706 USA
| | - Timothy A Hacker
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706 USA
| | - Daniel S Greenspan
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53706 USA
| | - Naomi C Chesler
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, WI 53706 USA.,Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706 USA
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17
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Kandel J, Picard M, Wallace DC, Eckmann DM. Mitochondrial DNA 3243A>G heteroplasmy is associated with changes in cytoskeletal protein expression and cell mechanics. J R Soc Interface 2018; 14:rsif.2017.0071. [PMID: 28592659 DOI: 10.1098/rsif.2017.0071] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 05/09/2017] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial and mechanical alterations in cells have both been shown to be hallmarks of human disease. However, little research has endeavoured to establish connections between these two essential features of cells in both functional and dysfunctional situations. In this work, we hypothesized that a specific genetic alteration in mitochondrial function known to cause human disease would trigger changes in cell mechanics. Using a previously characterized set of mitochondrial cybrid cell lines, we examined the relationship between heteroplasmy for the mitochondrial DNA (mtDNA) 3243A>G mutation, the cell cytoskeleton, and resulting cellular mechanical properties. We found that cells with increasing mitochondrial dysfunction markedly differed from one another in gene expression and protein production of various co-regulated cytoskeletal elements. The intracellular positioning and organization of actin also differed across cell lines. To explore the relationship between these changes and cell mechanics, we then measured cellular mechanical properties using atomic force microscopy and found that cell stiffness correlated with gene expression data for known determinants of cell mechanics, γ-actin, α-actinin and filamin A. This work points towards a mechanism linking mitochondrial genetics to single-cell mechanical properties. The transcriptional and structural regulation of cytoskeletal components by mitochondrial function may explain why energetic and mechanical alterations often coexist in clinical conditions.
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Affiliation(s)
- Judith Kandel
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Martin Picard
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David M Eckmann
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA .,Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
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18
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Lee SR, Han J. Mitochondrial Mutations in Cardiac Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:81-111. [PMID: 28551783 DOI: 10.1007/978-3-319-55330-6_5] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mitochondria individually encapsulate their own genome, unlike other cellular organelles. Mitochondrial DNA (mtDNA) is a circular, double-stranded, 16,569-base paired DNA containing 37 genes: 13 proteins of the mitochondrial respiratory chain, two ribosomal RNAs (rRNAs; 12S and 16S), and 22 transfer RNAs (tRNAs). The mtDNA is more vulnerable to oxidative modifications compared to nuclear DNA because of its proximity to ROS-producing sites, limited presence of DNA damage repair systems, and continuous replication in the cell. mtDNA mutations can be inherited or sporadic. Simple mtDNA mutations are point mutations, which are frequently found in mitochondrial tRNA loci, causing mischarging of mitochondrial tRNAs or deletion, duplication, or reduction in mtDNA content. Because mtDNA has multiple copies and a specific replication mechanism in cells or tissues, it can be heterogenous, resulting in characteristic phenotypic presentations such as heteroplasmy, genetic drift, and threshold effects. Recent studies have increased the understanding of basic mitochondrial genetics, providing an insight into the correlations between mitochondrial mutations and cardiac manifestations including hypertrophic or dilated cardiomyopathy, arrhythmia, autonomic nervous system dysfunction, heart failure, or sudden cardiac death with a syndromic or non-syndromic phenotype. Clinical manifestations of mitochondrial mutations, which result from structural defects, functional impairment, or both, are increasingly detected but are not clear because of the complex interplay between the mitochondrial and nuclear genomes, even in homoplasmic mitochondrial populations. Additionally, various factors such as individual susceptibility, nutritional state, and exposure to chemicals can influence phenotypic presentation, even for the same mtDNA mutation.In this chapter, we summarize our current understanding of mtDNA mutations and their role in cardiac involvement. In addition, epigenetic modifications of mtDNA are briefly discussed for future elucidation of their critical role in cardiac involvement. Finally, current strategies for dealing with mitochondrial mutations in cardiac disorders are briefly stated.
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Affiliation(s)
- Sung Ryul Lee
- Department of Integrated Biomedical Science, Cardiovascular and Metabolic Disease Center, College of Medicine, Inje University, Busan, 47392, South Korea
| | - Jin Han
- National Research Laboratory for Mitochondrial Signaling, Cardiovascular and Metabolic Disease Center, Department of Physiology, College of Medicine, Inje University, Busan, 47392, South Korea.
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19
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Chan SSL. Inherited mitochondrial genomic instability and chemical exposures. Toxicology 2017; 391:75-83. [PMID: 28756246 DOI: 10.1016/j.tox.2017.07.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/12/2017] [Accepted: 07/24/2017] [Indexed: 12/21/2022]
Abstract
There are approximately 1500 proteins that are needed for mitochondrial structure and function, most of which are encoded in the nuclear genome (Calvo et al., 2006). Each mitochondrion has its own genome (mtDNA), which in humans encodes 13 polypeptides, 22 tRNAs and 2 rRNAs required for oxidative phosphorylation. The mitochondrial genome of humans and most vertebrates is approximately 16.5kbp, double-stranded, circular, with few non-coding bases. Thus, maintaining mtDNA stability, that is, the ability of the cell to maintain adequate levels of mtDNA template for oxidative phosphorylation is essential and can be impacted by the level of mtDNA mutation currently within the cell or mitochondrion, but also from errors made during normal mtDNA replication, defects in mitochondrial quality control mechanisms, and exacerbated by exposures to exogenous and/or endogenous genotoxic agents. In this review, we expand on the origins and consequences of mtDNA instability, the current state of research regarding the mechanisms by which mtDNA instability can be overcome by cellular and chemical interventions, and the future of research and treatments for mtDNA instability.
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Affiliation(s)
- Sherine S L Chan
- Drug Discovery and Biomedical Sciences, College of Pharmacy, Medical University of South Carolina, Charleston, SC 29425, United States; Neuroene Therapeutics, Mt. Pleasant, SC 29464, United States.
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20
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Golob MJ, Tabima DM, Wolf GD, Johnston JL, Forouzan O, Mulchrone AM, Kellihan HB, Bates ML, Chesler NC. Pulmonary arterial strain- and remodeling-induced stiffening are differentiated in a chronic model of pulmonary hypertension. J Biomech 2017; 55:92-98. [PMID: 28262286 DOI: 10.1016/j.jbiomech.2017.02.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 01/30/2017] [Accepted: 02/11/2017] [Indexed: 02/06/2023]
Abstract
Pulmonary hypertension (PH) is a debilitating vascular disease that leads to pulmonary artery (PA) stiffening, which is a predictor of patient mortality. During PH development, PA stiffening adversely affects right ventricular function. PA stiffening has been investigated through the arterial nonlinear elastic response during mechanical testing using a canine PH model. However, only circumferential properties were reported and in the absence of chronic PH-induced PA remodeling. Remodeling can alter arterial nonlinear elastic properties via chronic changes in extracellular matrix (ECM) content and geometry. Here, we used an established constitutive model to demonstrate and differentiate between strain-stiffening, which is due to nonlinear elasticity, and remodeling-induced stiffening, which is due to ECM and geometric changes, in a canine model of chronic thromboembolic PH (CTEPH). To do this, circumferential and axial tissue strips of large extralobar PAs from control and CTEPH tissues were tested in uniaxial tension, and data were fit to a phenomenological constitutive model. Strain-induced stiffening was evident from mechanical testing as nonlinear elasticity in both directions and computationally by a high correlation coefficient between the mechanical data and model (R2=0.89). Remodeling-induced stiffening was evident from a significant increase in the constitutive model stress parameter, which correlated with increased PA collagen content and decreased PA elastin content as measured histologically. The ability to differentiate between strain- and remodeling-induced stiffening in vivo may lead to tailored clinical treatments for PA stiffening in PH patients.
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Affiliation(s)
- Mark J Golob
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, WI 53706, United States
| | - Diana M Tabima
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, WI 53706, United States
| | - Gregory D Wolf
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, WI 53706, United States
| | - James L Johnston
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, WI 53706, United States
| | - Omid Forouzan
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, WI 53706, United States
| | - Ashley M Mulchrone
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, WI 53706, United States
| | - Heidi B Kellihan
- Department of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Melissa L Bates
- Department of Physiology, University of Iowa, Iowa City, IA 52242, United States
| | - Naomi C Chesler
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, WI 53706, United States.
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21
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Golob MJ, Wang Z, Prostrollo AJ, Hacker TA, Chesler NC. Limiting collagen turnover via collagenase-resistance attenuates right ventricular dysfunction and fibrosis in pulmonary arterial hypertension. Physiol Rep 2016; 4:4/11/e12815. [PMID: 27252252 PMCID: PMC4908492 DOI: 10.14814/phy2.12815] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 05/03/2016] [Indexed: 12/22/2022] Open
Abstract
Pulmonary arterial hypertension (PAH) is a severe form of pulmonary hypertension in which right ventricular (RV) afterload is increased and death typically occurs due to decompensated RV hypertrophy and failure. Collagen accumulation has been implicated in pulmonary artery remodeling, but how it affects RV performance remains unclear. Here, we sought to identify the role of collagen turnover, defined as the balance between collagen synthesis and degradation, in RV structure and function in PAH. To do so, we exposed mutant (Col1a1R/R) mice, in which collagen type I degradation is impaired such that collagen turnover is reduced, and wild‐type (Col1a1+/+) littermates to 14 days of chronic hypoxia combined with SUGEN treatment (HySu) to recapitulate characteristics of clinical PAH. RV structure and function were measured by echocardiography, RV catheterization, and histology. Despite comparable increases in RV systolic pressure (Col1a1+/+: 46 ± 2 mmHg; Col1a1R/R: 47 ± 3 mmHg), the impaired collagen degradation in Col1a1R/R mice resulted in no RV collagen accumulation, limited RV hypertrophy, and maintained right ventricular‐pulmonary vascular coupling with HySu exposure. The preservation of cardiac function in the mutant mice indicates a beneficial role of limited collagen turnover via impaired degradation in RV remodeling in response to chronic pressure overload. Our results suggest novel treatments that reduce collagen turnover may offer a new therapeutic strategy for PAH patients.
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Affiliation(s)
- Mark J Golob
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, Wisconsin Materials Science Program, University of Wisconsin-Madison College of Engineering, Madison, Wisconsin
| | - Zhijie Wang
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, Wisconsin
| | - Anthony J Prostrollo
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, Wisconsin
| | - Timothy A Hacker
- Department of Medicine, Medical Science Center University of Wisconsin-Madison, Madison, Wisconsin
| | - Naomi C Chesler
- Department of Biomedical Engineering, University of Wisconsin-Madison College of Engineering, Madison, Wisconsin
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22
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Popkov VA, Plotnikov EY, Silachev DN, Zorova LD, Pevzner IB, Jankauskas SS, Zorov SD, Babenko VA, Zorov DB. Diseases and Aging: Gender Matters. BIOCHEMISTRY (MOSCOW) 2016; 80:1560-70. [PMID: 26638680 DOI: 10.1134/s0006297915120032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
At first glance, biological differences between male and female sex seem obvious, but, in fact, they affect a vast number of deeper levels apart from reproductive function and related physiological features. Such differences affect all organizational levels including features of cell physiology and even functioning of separate organelles, which, among other things, account for such global processes as resistance to diseases and aging. Understanding of mechanisms underlying resistance of one of the sexes to pathological processes and aging will allow taking into consideration gender differences while developing drugs and therapeutic approaches, and it will provide an opportunity to reproduce and enhance such resistance in the more vulnerable gender. Here we review physiological as well as cellular and biological features of disease course including aging that are affected by gender and discuss potential mechanisms behind these processes. Such mechanisms include features of oxidative metabolism and mitochondrial functioning.
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Affiliation(s)
- V A Popkov
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, 119991, Russia.
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23
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Mitochondrial signaling in the vascular endothelium: beyond reactive oxygen species. Basic Res Cardiol 2016; 111:26. [PMID: 26992928 DOI: 10.1007/s00395-016-0546-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 03/09/2016] [Indexed: 02/07/2023]
Abstract
Traditionally, the mitochondria have been viewed as the cell's powerhouse, producing energy in the form of ATP. As a byproduct of ATP formation, the mitochondrial electron transport chain produces substantial amounts of reactive oxygen species (ROS). First thought to be toxic, recent literature indicates an important signaling function for mitochondria-derived ROS, especially in relation to cardiovascular disease pathogenesis. This has spawned an evolution to a more contemporary view of mitochondrial function as a dynamic organelle involved in key regulatory and cell survival processes. Beyond ROS, recent studies have identified a host of mitochondria-linked factors that influence the cellular and extracellular environments, including mitochondria-derived peptides, mitochondria-localized proteins, and the mitochondrial genome itself. Interestingly, many of these factors help orchestrate ROS homeostasis and ROS-related signaling. The paradigm defining the role of mitochondria in the vasculature needs to be updated yet again to include these key signaling factors, which serves as the focus of the current review. In describing these novel signaling factors, we pay specific attention to their influence on endothelial homeostasis. Therapies targeting these pathways are discussed, as are emerging research directions.
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24
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A composite peripheral blood gene expression measure as a potential diagnostic biomarker in bipolar disorder. Transl Psychiatry 2015; 5:e614. [PMID: 26241352 PMCID: PMC4564565 DOI: 10.1038/tp.2015.110] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 06/15/2015] [Accepted: 06/25/2015] [Indexed: 12/11/2022] Open
Abstract
Gene expression in peripheral blood has the potential to inform on pathophysiological mechanisms and has emerged as a viable avenue for the identification of biomarkers. Here, we aimed to identify gene expression candidate genes and to explore the potential for a composite gene expression measure as a diagnostic and state biomarker in bipolar disorder. First, messenger RNA levels of 19 candidate genes were assessed in peripheral blood mononuclear cells of 37 rapid cycling bipolar disorder patients in different affective states (depression, mania and euthymia) during a 6-12-month period and in 40 age- and gender-matched healthy control subjects. Second, a composite gene expression measure was constructed in the first half study sample and independently validated in the second half of the sample. We found downregulation of POLG and OGG1 expression in bipolar disorder patients compared with healthy control subjects. In patients with bipolar disorder, upregulation of NDUFV2 was observed in a depressed state compared with a euthymic state. The composite gene expression measure for discrimination between patients and healthy control subjects on the basis of 19 genes generated an area under the receiver-operating characteristic curve of 0.81 (P < 0.0001) in sample 1, which was replicated with a value of 0.73 (P < 0.0001) in sample 2, corresponding with a moderately accurate test. The present findings of altered POLG, OGG1 and NDUFV2 expression point to disturbances within mitochondrial function and DNA repair mechanisms in bipolar disorder. Further, a composite gene expression measure could hold promise as a potential diagnostic biomarker.
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25
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Tian L, Henningsen J, Salick MR, Crone WC, Gunderson M, Dailey SH, Chesler NC. Stretch calculated from grip distance accurately approximates mid-specimen stretch in large elastic arteries in uniaxial tensile tests. J Mech Behav Biomed Mater 2015; 47:107-113. [PMID: 25881308 DOI: 10.1016/j.jmbbm.2015.03.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 03/14/2015] [Accepted: 03/23/2015] [Indexed: 02/02/2023]
Abstract
The mechanical properties of vascular tissues affect hemodynamics and can alter disease progression. The uniaxial tensile test is a simple and effective method for determining the stress-strain relationship in arterial tissue ex vivo. To enable calculation of strain, stretch can be measured directly with image tracking of markers on the tissue or indirectly from the distance between the grips used to hold the specimen. While the imaging technique is generally considered more accurate, it also requires more analysis, and the grip distance method is more widely used. The purpose of this study is to compare the stretch of the testing specimen calculated from the grip distance method to that obtained from the imaging method for canine descending aortas and large proximal pulmonary arteries. Our results showed a significant difference in stretch between the two methods; however, this difference was consistently less than 2%. Therefore, the grip distance method is an accurate approximation of the stretch in large elastic arteries in the uniaxial tensile test.
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Affiliation(s)
- Lian Tian
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706-1609, USA
| | - Joseph Henningsen
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706-1609, USA
| | - Max R Salick
- Department of Engineering Physics, University of Wisconsin-Madison, Madison, WI 53706-1609, USA
| | - Wendy C Crone
- Department of Engineering Physics, University of Wisconsin-Madison, Madison, WI 53706-1609, USA
| | - McLean Gunderson
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin-Madison, Madison, WI 53792-3252, USA
| | - Seth H Dailey
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin-Madison, Madison, WI 53792-3252, USA
| | - Naomi C Chesler
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706-1609, USA.
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