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Balakrishnan R, Garcia PA, Veluthakal R, Huss JM, Hoolachan JM, Thurmond DC. Toward Ameliorating Insulin Resistance: Targeting a Novel PAK1 Signaling Pathway Required for Skeletal Muscle Mitochondrial Function. Antioxidants (Basel) 2023; 12:1658. [PMID: 37759961 PMCID: PMC10525748 DOI: 10.3390/antiox12091658] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 08/10/2023] [Accepted: 08/15/2023] [Indexed: 09/29/2023] Open
Abstract
The p21-activated kinase 1 (PAK1) is required for insulin-stimulated glucose uptake in skeletal muscle cells. However, whether PAK1 regulates skeletal muscle mitochondrial function, which is a central determinant of insulin sensitivity, is unknown. Here, the effect of modulating PAK1 levels (knockdown via siRNA, overexpression via adenoviral transduction, and/or inhibition of activation via IPA3) on mitochondrial function was assessed in normal and/or insulin-resistant rat L6.GLUT4myc and human muscle (LHCN-M2) myotubes. Human type 2 diabetes (T2D) and non-diabetic (ND) skeletal muscle samples were also used for validation of the identified signaling elements. PAK1 depletion in myotubes decreased mitochondrial copy number, respiration, altered mitochondrial structure, downregulated PGC1α (a core regulator of mitochondrial biogenesis and oxidative metabolism) and PGC1α activators, p38 mitogen-activated protein kinase (p38MAPK) and activating transcription factor 2 (ATF2). PAK1 enrichment in insulin-resistant myotubes improved mitochondrial function and rescued PGC1α expression levels. Activated PAK1 was localized to the cytoplasm, and PAK1 enrichment concurrent with p38MAPK inhibition did not increase PGC1α levels. PAK1 inhibition and enrichment also modified nuclear phosphorylated-ATF2 levels. T2D human samples showed a deficit for PGC1α, and PAK1 depletion in LHCN-M2 cells led to reduced mitochondrial respiration. Overall, the results suggest that PAK1 regulates muscle mitochondrial function upstream of the p38MAPK/ATF2/PGC1α-axis pathway.
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Affiliation(s)
- Rekha Balakrishnan
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, 1500 E Duarte Road, Duarte, CA 91010, USA; (R.B.); (R.V.)
| | - Pablo A. Garcia
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, 1500 E Duarte Road, Duarte, CA 91010, USA; (R.B.); (R.V.)
| | - Rajakrishnan Veluthakal
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, 1500 E Duarte Road, Duarte, CA 91010, USA; (R.B.); (R.V.)
| | - Janice M. Huss
- School of Medicine, Washington University, 660 S Euclid Ave, St. Louis, MO 63110, USA;
| | - Joseph M. Hoolachan
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, 1500 E Duarte Road, Duarte, CA 91010, USA; (R.B.); (R.V.)
| | - Debbie C. Thurmond
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, City of Hope Beckman Research Institute, 1500 E Duarte Road, Duarte, CA 91010, USA; (R.B.); (R.V.)
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Zhang Z, Li GY, Jiang Y, Zheng Y, Gower AL, Destrade M, Cao Y. Noninvasive measurement of local stress inside soft materials with programmed shear waves. SCIENCE ADVANCES 2023; 9:eadd4082. [PMID: 36888699 PMCID: PMC9995030 DOI: 10.1126/sciadv.add4082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Mechanical stresses across different length scales play a fundamental role in understanding biological systems' functions and engineering soft machines and devices. However, it is challenging to noninvasively probe local mechanical stresses in situ, particularly when the mechanical properties are unknown. We propose an acoustoelastic imaging-based method to infer the local stresses in soft materials by measuring the speeds of shear waves induced by custom-programmed acoustic radiation force. Using an ultrasound transducer to excite and track the shear waves remotely, we demonstrate the application of the method by imaging uniaxial and bending stresses in an isotropic hydrogel and the passive uniaxial stress in a skeletal muscle. These measurements were all done without the knowledge of the constitutive parameters of the materials. The experiments indicate that our method will find broad applications, ranging from health monitoring of soft structures and machines to diagnosing diseases that alter stresses in soft tissues.
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Affiliation(s)
- Zhaoyi Zhang
- Institute of Biomechanics and Medical Engineering, AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P.R. China
| | - Guo-Yang Li
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02139, USA
| | - Yuxuan Jiang
- Institute of Biomechanics and Medical Engineering, AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P.R. China
| | - Yang Zheng
- Institute of Biomechanics and Medical Engineering, AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P.R. China
| | - Artur L. Gower
- Department of Mechanical Engineering, University of Sheffield, Sheffield, UK
| | - Michel Destrade
- School of Mathematical and Statistical Sciences, University of Galway, Galway, Ireland
- Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province and Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, Zhejiang Province, P.R. China
| | - Yanping Cao
- Institute of Biomechanics and Medical Engineering, AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P.R. China
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A single arm trial using passive simulated jogging for blunting acute hyperglycemia. Sci Rep 2021; 11:6437. [PMID: 33742027 PMCID: PMC7979828 DOI: 10.1038/s41598-021-85579-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 03/03/2021] [Indexed: 01/08/2023] Open
Abstract
Glycemic fluctuations increase oxidative stress, promote endothelial dysfunction and cardiovascular disease. Reducing glycemic fluctuations is beneficial. We previously reported that a portable motorized passive simulated jogging device, (JD) reduces 24 h glycemic indices in type 2 and non-diabetic subjects. This study evaluates effectiveness and feasibility of JD in blunting large glycemic fluctuation induced by an oral glucose tolerance test (OGTT). The study was performed in 10 adult participants mean age 41.3 ± 13.5 year using interstitial glucose monitor (IG). Each participant fasted for 8 h. followed by an OGTT (Pre-JD), thereafter JD was used for 90 min per day for 7 days, without change to diet or activities of daily living. A repeat OGTT (Post-JD) was performed after completion. The integrated area under the curve (iAUC2h–4h) was computed for the OGTT Pre-JD and Post-JD. Seven days of JD blunted the glucose fluctuation produced by OGTT. JD decreased AUC2h by 17 ± 4.7% and iAUC4h by 15 ± 5.9% (p < 0.03). In healthy mostly obese participants 7 days of JD blunts the hyperglycemic response produced by an OGTT. JD may be an adjunct to current glycemic management, it can be applied in different postures for those who cannot (due to physical or cognitive limitations) or will not exercise. Trial registration:ClinicalTrials.gov NCT03550105 (08-06-2018).
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Abstract
The skeletal muscle is the largest organ in the body, by mass. It is also the regulator of glucose homeostasis, responsible for 80% of postprandial glucose uptake from the circulation. Skeletal muscle is essential for metabolism, both for its role in glucose uptake and its importance in exercise and metabolic disease. In this article, we give an overview of the importance of skeletal muscle in metabolism, describing its role in glucose uptake and the diseases that are associated with skeletal muscle metabolic dysregulation. We focus on the role of skeletal muscle in peripheral insulin resistance and the potential for skeletal muscle-targeted therapeutics to combat insulin resistance and diabetes, as well as other metabolic diseases like aging and obesity. In particular, we outline the possibilities and pitfalls of the quest for exercise mimetics, which are intended to target the molecular mechanisms underlying the beneficial effects of exercise on metabolic disease. We also provide a description of the molecular mechanisms that regulate skeletal muscle glucose uptake, including a focus on the SNARE proteins, which are essential regulators of glucose transport into the skeletal muscle. © 2020 American Physiological Society. Compr Physiol 10:785-809, 2020.
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Affiliation(s)
- Karla E. Merz
- Department of Molecular and Cellular Endocrinology, City of Hope Beckman Research Institute, Duarte, California, USA
- The Irell and Manella Graduate School of Biological Sciences, City of Hope, Duarte, California, USA
| | - Debbie C. Thurmond
- Department of Molecular and Cellular Endocrinology, City of Hope Beckman Research Institute, Duarte, California, USA
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Venturelli M, Rampichini S, Coratella G, Limonta E, Bisconti AV, Cè E, Esposito F. Heart and musculoskeletal hemodynamic responses to repetitive bouts of quadriceps static stretching. J Appl Physiol (1985) 2019; 127:376-384. [PMID: 31161884 DOI: 10.1152/japplphysiol.00823.2018] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The role of sympathetic and parasympathetic activity in relation to the repetitive exposure to static stretching (SS) on heart and musculoskeletal hemodynamics in stretched and resting muscles is still a matter of debate. The aim of the study was to determine cardiac and musculoskeletal hemodynamics to repetitive bouts of unilateral SS. Sympathetic and parasympathetic activity contribution to the central hemodynamics and local difference in circulation of stretched and resting muscles were also investigated. In eight participants, heart rate (HR), cardiac output (CO), mean arterial pressure (MAP), HR variability (HRV), blood pressure variability (BPV), and blood flow in passively stretched limb (SL) and control (CL, resting limb) were measured during five bouts of unilateral SS (45 s of knee flexion and 15 s of knee extension). SS increased sympathetic (~20%) and decreased parasympathetic activity (~30%) with a prevalence of parasympathetic withdrawal. During SS, HR, CO, and MAP increased by ~18 beats/min, ~0.29 l/min, ~12 mmHg, respectively. Peak blood flow in response to the first stretching maneuver increased significantly (+377 ± 95 ml/min) in the SL and reduced significantly (-57 ± 48 ml/min) in the CL. This between-limb difference in local circulation response to SS disappeared after the second SS bout. These results indicate that heart hemodynamic responses to SS are primarily influenced by the parasympathetic withdrawal rather than by the increase in sympathetic activity. The balance between neural and local factors contributing to blood flow regulation was affected by the level of SS exposure, likely associated with differences in the bioavailability of local vasoactive factors throughout the stretching bouts.NEW & NOTEWORTHY Repetitive exposure to static stretching (SS) on heart and musculoskeletal hemodynamics in stretched and remote muscles may be influenced by neural and local factors. We documented that SS-induced heart hemodynamic responses are primarily influenced by parasympathetic withdrawal. The balance between neural and local factors contributing to the regulation of musculoskeletal hemodynamics is dependent on SS exposure possibly because of different local vasoactive factor bioavailability during the subsequent stretching bouts.
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Affiliation(s)
- Massimo Venturelli
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy.,Department of Neurosciences, Biomedicine and Movement Sciences. University of Verona, Verona, Italy.,Department of Internal Medicine, Section of Geriatrics, University of Utah, Salt Lake City, Utah
| | - Susanna Rampichini
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
| | - Giuseppe Coratella
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
| | - Eloisa Limonta
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy.,IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | - Angela Valentina Bisconti
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy.,Department of Internal Medicine, Section of Geriatrics, University of Utah, Salt Lake City, Utah
| | - Emiliano Cè
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy.,IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | - Fabio Esposito
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy.,IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
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