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Ojha KR, Shin SY, Padgham S, Leon Olmedo F, Guo B, Han G, Woodman C, Trache A. Age-Associated Dysregulation of Integrin Function in Vascular Smooth Muscle. Front Physiol 2022; 13:913673. [PMID: 35874532 PMCID: PMC9301045 DOI: 10.3389/fphys.2022.913673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/06/2022] [Indexed: 11/13/2022] Open
Abstract
Arterial aging results in a progressive reduction in elasticity of the vessel wall and an impaired ability of aged blood vessels to control local blood flow and pressure. Recently, a new concept has emerged that the stiffness and decreased contractility of vascular smooth muscle (VSM) cells are important contributors to age-induced arterial dysfunction. This study investigated the hypothesis that aging alters integrin function in a matrix stiffness-dependent manner, which contributes to decreased VSM contractility in aged soleus muscle feed arteries (SFA). The effect of RGD-binding integrins on contractile function of cannulated SFA isolated from young (4 months) and old (24 months) Fischer 344 rats was assessed by measuring constrictor responses to norepinephrine, phenylephrine, and angiotensin II. Results indicated that constrictor responses in presence of RGD were impaired in old compared to young SFA. VSM cells isolated from young and old SFA were used for functional experiments using atomic force microscopy and high-resolution imaging. Aging was associated with a modulation of integrin β1 recruitment at cell-matrix adhesions that was matrix and substrate stiffness dependent. Our data showed that substrate stiffening drives altered integrin β1 expression in aging, while soft substrates abolish age-induced differences in overall integrin β1 expression. In addition, substrate stiffness and matrix composition contribute to the modulation of SMα-actin cytoskeleton architecture with soft substrates reducing age effects. Our results provide new insights into age-induced structural changes at VSM cell level that translates to decreased functionality of aged resistance soleus feed arteries.
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Affiliation(s)
- Krishna Raj Ojha
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, TX, United States
| | - Song Yi Shin
- Department of Health and Kinesiology, Texas A&M University, College Station, TX, United States
| | - Samuel Padgham
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, TX, United States
| | - Frida Leon Olmedo
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, United States
| | - Bohong Guo
- Department of Epidemiology and Statistics, Texas A&M University Health Science Center, College Station, TX, United States
| | - Gang Han
- Department of Epidemiology and Statistics, Texas A&M University Health Science Center, College Station, TX, United States
| | - Christopher Woodman
- Department of Health and Kinesiology, Texas A&M University, College Station, TX, United States
| | - Andreea Trache
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, TX, United States
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, United States
- *Correspondence: Andreea Trache,
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Abstract
Vascular smooth muscle cells (VSMC) are now considered important contributors to the pathophysiological and biophysical mechanisms underlying arterial stiffening in aging. Here, we review mechanisms whereby VSMC stiffening alters vascular function and contributes to the changes in vascular stiffening observed in aging and cardiovascular disease. Vascular stiffening in arterial aging was historically associated with changes in the extracellular matrix; however, new evidence suggests that endothelial and vascular smooth muscle cell stiffness also contribute to overall blood vessel stiffness. Furthermore, VSMC play an integral role in regulating matrix deposition and vessel wall contractility via interaction between the actomyosin contractile unit and adhesion structures that anchor the cell within the extracellular matrix. Aged-induce phenotypic modulation of VSMC from a contractile to a synthetic phenotype is associated with decreased cellular contractility and increased cell stiffness. Aged VSMC also display reduced mechanosensitivity and adaptation to mechanical signals from their microenvironment due to impaired intracellular signaling. Finally, evidence for decreased contractility in arteries from aged animals demonstrate that changes at the cellular level result in decreased functional properties at the tissue level.
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Heaps CL, Bray JF, Parker JL. Enhanced KCl-mediated contractility and Ca 2+ sensitization in porcine collateral-dependent coronary arteries persist after exercise training. Am J Physiol Heart Circ Physiol 2020; 319:H915-H926. [PMID: 32857599 DOI: 10.1152/ajpheart.00384.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We have previously reported enhanced Ca2+ sensitivity of coronary arteries that is dependent upon collateral circulation for their blood supply. For the current study, we hypothesized that small collateral-dependent arteries would exhibit an enhanced KCl-mediated contractile response attributable to Ca2+ sensitization and increased Ca2+ channel current. Ameroid constrictors were surgically placed around the left circumflex (LCX) artery of female Yucatan miniature swine. Eight weeks postoperatively, pigs were randomized into sedentary or exercise-trained (treadmill run; 5 days/wk; 14 wk) groups. Small coronary arteries (150-300 μm luminal diameter) were isolated from myocardial regions distal to the collateral-dependent LCX and the nonoccluded left anterior descending arteries. Contractile tension and simultaneous measures of both tension and intracellular free Ca2+ levels (fura-2) were measured in response to increasing concentrations of KCl. In addition, whole cell Ca2+ currents were also obtained. Chronic occlusion enhanced contractile responses to KCl and increased Ca2+ sensitization in collateral-dependent compared with nonoccluded arteries of both sedentary and exercise-trained pigs. In contrast, smooth muscle cell Ca2+ channel current was not altered by occlusion or exercise training. Ca2+/calmodulin-dependent protein kinase II (CaMKII; inhibited by KN-93, 0.3-1 μM) contributed to the enhanced contractile response in collateral-dependent arteries of sedentary pigs, whereas both CaMKII and Rho-kinase (inhibited by hydroxyfasudil, 30 μM or Y27632, 10 μM) contributed to increased contraction in exercise-trained animals. Taken together, these data suggest that chronic occlusion leads to enhanced contractile responses to KCl in collateral-dependent coronary arteries via increased Ca2+ sensitization, a response that is further augmented with exercise training.NEW & NOTEWORTHY Small coronary arteries distal to chronic occlusion displayed enhanced contractile responses, which were further augmented after exercise training and attributable to enhanced calcium sensitization without alterations in calcium channel current. The calcium sensitization mediators Rho-kinase and CaMKII significantly contributed to enhanced contraction in collateral-dependent arteries of exercise-trained, but not sedentary, pigs. Exercise-enhanced contractile responses may increase resting arterial tone, creating an enhanced coronary flow reserve that is accessible during periods of increased metabolic demand.
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Affiliation(s)
- Cristine L Heaps
- Department of Physiology and Pharmacology, Texas A&M University, College Station, Texas.,Michael E. DeBakey Institute for Comparative Cardiovascular Science and Biomedical Devices, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas
| | - Jeff F Bray
- Department of Physiology and Pharmacology, Texas A&M University, College Station, Texas
| | - Janet L Parker
- Michael E. DeBakey Institute for Comparative Cardiovascular Science and Biomedical Devices, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas.,Department of Medical Physiology, Texas A&M Health Science Center, Texas A&M University, College Station, Texas
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Woodman CR, Seawright JW, Luttrell MJ, Shin SY, Trache A. Importance of mechanical signals in promoting exercise-induced improvements in vasomotor function of aged skeletal muscle resistance arteries. Am J Physiol Heart Circ Physiol 2018; 315:H602-H609. [PMID: 29906226 DOI: 10.1152/ajpheart.00732.2017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Current research indicates that vasomotor responses are altered with aging in skeletal muscle resistance arteries. The changes in vasomotor function are characterized by impaired vasodilator and vasoconstrictor responses. The detrimental effects of aging on vasomotor function are attenuated in some vascular beds after a program of endurance exercise training. The signals associated with exercise responsible for inducing improvements in vasomotor function have been proposed to involve short-duration increases in intraluminal shear stress and/or pressure during individual bouts of exercise. Here, we review evidence that increases in shear stress and pressure, within a range believed to present in these arteries during exercise, promote healthy vasomotor function in aged resistance arteries. We conclude that available research is consistent with the interpretation that short-duration mechanical stimulation, through increases in shear stress and pressure, contributes to the beneficial effects of exercise on vasomotor function in aged skeletal muscle resistance arteries.
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Affiliation(s)
- Christopher R Woodman
- Department of Health and Kinesiology, Texas A&M University , College Station, Texas.,Department of Veterinary Physiology and Pharmacology, Texas A&M University , College Station, Texas
| | - John W Seawright
- Department of Health and Kinesiology, Texas A&M University , College Station, Texas
| | | | - Song Yi Shin
- Department of Health and Kinesiology, Texas A&M University , College Station, Texas
| | - Andreea Trache
- Department of Medical Physiology, Texas A&M University , College Station, Texas.,Department of Biomedical Engineering, Texas A&M University , College Station, Texas
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Seawright JW, Sreenivasappa H, Gibbs HC, Padgham S, Shin SY, Chaponnier C, Yeh AT, Trzeciakowski JP, Woodman CR, Trache A. Vascular Smooth Muscle Contractile Function Declines With Age in Skeletal Muscle Feed Arteries. Front Physiol 2018; 9:856. [PMID: 30108507 PMCID: PMC6079263 DOI: 10.3389/fphys.2018.00856] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/15/2018] [Indexed: 12/18/2022] Open
Abstract
Aging induces a progressive decline in vasoconstrictor responses in central and peripheral arteries. This study investigated the hypothesis that vascular smooth muscle (VSM) contractile function declines with age in soleus muscle feed arteries (SFA). Contractile function of cannulated SFA isolated from young (4 months) and old (24 months) Fischer 344 rats was assessed by measuring constrictor responses of denuded (endothelium removed) SFA to norepinephrine (NE), phenylephrine (PE), and angiotensin II (Ang II). In addition, we investigated the role of RhoA signaling in modulation of VSM contractile function. Structural and functional characteristics of VSM cells were evaluated by fluorescence imaging and atomic force microscopy (AFM). Results indicated that constrictor responses to PE and Ang II were significantly impaired in old SFA, whereas constrictor responses to NE were preserved. In the presence of a Rho-kinase inhibitor (Y27632), constrictor responses to NE, Ang II, and PE were significantly reduced in young and old SFA. In addition, the age-group difference in constrictor responses to Ang II was eliminated. ROCK1 and ROCK2 content was similar in young and old VSM cells, whereas pROCK1 and pROCK2 were significantly elevated in old VSM cells. Aging was associated with a reduction in smooth muscle α-actin stress fibers and recruitment of proteins to cell-matrix adhesions. Old VSM cells presented an increase in integrin adhesion to the matrix and smooth muscle γ-actin fibers that was associated with increased cell stiffness. In conclusion, our results indicate that VSM contractile function declined with age in SFA. The decrement in contractile function was mediated in part by RhoA/ROCK signaling. Upregulation of pROCK in old VSM cells was not able to rescue contractility in old SFA. Collectively, these results indicate that changes at the VSM cell level play a central role in the reduced contractile function of aged SFA.
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Affiliation(s)
- John W Seawright
- Department of Health and Kinesiology, Texas A&M University, College Station, TX, United States
| | - Harini Sreenivasappa
- Department of Medical Physiology, Texas A&M University Health Science Center, College Station, TX, United States
| | - Holly C Gibbs
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, United States
| | - Samuel Padgham
- Department of Medical Physiology, Texas A&M University Health Science Center, College Station, TX, United States
| | - Song Y Shin
- Department of Health and Kinesiology, Texas A&M University, College Station, TX, United States
| | - Christine Chaponnier
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Alvin T Yeh
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, United States
| | - Jerome P Trzeciakowski
- Department of Medical Physiology, Texas A&M University Health Science Center, College Station, TX, United States
| | - Christopher R Woodman
- Department of Health and Kinesiology, Texas A&M University, College Station, TX, United States.,Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX, United States
| | - Andreea Trache
- Department of Medical Physiology, Texas A&M University Health Science Center, College Station, TX, United States.,Department of Biomedical Engineering, Texas A&M University, College Station, TX, United States
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Gittemeier EM, Ericson T, Ghosh P, Copp SW, Opoku-Acheampong AB, Behnke BJ. Effects of aging and exercise training on the dynamics of vasoconstriction in skeletal muscle resistance vessels. Eur J Appl Physiol 2017; 117:397-407. [PMID: 28154974 DOI: 10.1007/s00421-017-3541-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 01/09/2017] [Indexed: 11/24/2022]
Abstract
It is unknown whether aging or exercise training affect the dynamics of arteriolar vasoconstriction. PURPOSE We hypothesized that old age will slow, and exercise training will speed, the dynamics of skeletal muscle arteriolar vasoconstriction in resistance vessels of aged rats. METHOD Young (6 month old) and aged (24 month old) male Fischer-344 rats were assigned to sedentary (Sed: n = 6/age group) or exercise-trained (ET: n = 5 aged and 6 young; via treadmill running for 10-12 weeks) groups. After completion of training, arterioles from the red portion of the gastrocnemius muscle were removed, cannulated, and exposed to 10-4 M norepinephrine (NE) or 20 mM caffeine. Changes in luminal diameter were recorded for analysis of constrictor dynamics. RESULT Old age blunted all kinetic parameters (i.e., time delay, time constant) resulting in vasoconstriction taking ~3 times as long to reach a steady state (SS) versus younger counterparts for NE (aged-sed: 15.6 ± 6.0 versus young-sed: 4.6 ± 0.5 s; P < 0.05) with a similar time course to caffeine. Exercise training resulted in a similar time to SS between age groups for NE (aged-ET: 6.8 ± 1.6 versus young-ET: 7.0 ± 0.6 s) and caffeine (aged-ET: 7.8 ± 0.6 versus young-ET: 8.6 ± 1.0 s). CONCLUSION The results of this study demonstrate that aging blunts the rate of vasoconstriction in skeletal muscle resistance vessels to the sympathetic neurotransmitter NE due, in part, to an attenuated rate of contraction from intracellular calcium release. Further, exercise training speeds the dynamics of constriction to both NE and caffeine with old age.
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Affiliation(s)
| | - Tyler Ericson
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - Payal Ghosh
- Department of Food, Nutrition and Exercise Sciences, Florida State University, Tallahassee, FL, USA
| | - Steven W Copp
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | | | - Bradley J Behnke
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA. .,Department of Kinesiology, Johnson Cancer Research Center, Kansas State University, Manhattan, KS, 66506, USA.
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