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Bibollet H, Nguyen EL, Miranda DR, Ward CW, Voss AA, Schneider MF, Hernández‐Ochoa EO. Voltage sensor current, SR Ca 2+ release, and Ca 2+ channel current during trains of action potential-like depolarizations of skeletal muscle fibers. Physiol Rep 2023; 11:e15675. [PMID: 37147904 PMCID: PMC10163276 DOI: 10.14814/phy2.15675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 05/07/2023] Open
Abstract
In skeletal muscle, CaV 1.1 serves as the voltage sensor for both excitation-contraction coupling (ECC) and L-type Ca2+ channel activation. We have recently adapted the technique of action potential (AP) voltage clamp (APVC) to monitor the current generated by the movement of intramembrane voltage sensors (IQ ) during single imposed transverse tubular AP-like depolarization waveforms (IQAP ). We now extend this procedure to monitoring IQAP , and Ca2+ currents during trains of tubular AP-like waveforms in adult murine skeletal muscle fibers, and compare them with the trajectories of APs and AP-induced Ca2+ release measured in other fibers using field stimulation and optical probes. The AP waveform remains relatively constant during brief trains (<1 sec) for propagating APs in non-V clamped fibers. Trains of 10 AP-like depolarizations at 10 Hz (900 ms), 50 Hz (180 ms), or 100 Hz (90 ms) did not alter IQAP amplitude or kinetics, consistent with previous findings in isolated muscle fibers where negligible charge immobilization occurred during 100 ms step depolarizations. Using field stimulation, Ca2+ release did exhibit a considerable decline from pulse to pulse during the train, also consistent with previous findings, indicating that the decline of Ca2+ release during a short train of APs is not correlated to modification of charge movement. Ca2+ currents during single or 10 Hz trains of AP-like depolarizations were hardly detectable, were minimal during 50 Hz trains, and became more evident during 100 Hz trains in some fibers. Our results verify predictions on the behavior of the ECC machinery in response to AP-like depolarizations and provide a direct demonstration that Ca2+ currents elicited by single AP-like waveforms are negligible, but can become more prominent in some fibers during short high-frequency train stimulation that elicits maximal isometric force.
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Affiliation(s)
- Hugo Bibollet
- Department of Biochemistry and Molecular BiologyUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Elton L. Nguyen
- Department of Biological SciencesWright State UniversityDaytonOhioUSA
| | - Daniel R. Miranda
- Department of Biological SciencesWright State UniversityDaytonOhioUSA
| | - Christopher W. Ward
- Department of OrthopedicsUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Andrew A. Voss
- Department of Biological SciencesWright State UniversityDaytonOhioUSA
| | - Martin F. Schneider
- Department of Biochemistry and Molecular BiologyUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Erick O. Hernández‐Ochoa
- Department of Biochemistry and Molecular BiologyUniversity of Maryland School of MedicineBaltimoreMarylandUSA
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2
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Velasquez FC, Roman B, Hernández-Ochoa EO, Leppo MK, Truong SK, Steenbergen C, Schneider MF, Weiss RG, Das S. Contribution of skeletal muscle-specific microRNA-133b to insulin resistance in heart failure. Am J Physiol Heart Circ Physiol 2023; 324:H598-H609. [PMID: 36827227 PMCID: PMC10069972 DOI: 10.1152/ajpheart.00250.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 02/25/2023]
Abstract
Insulin resistance (IR) is one of the hallmarks of heart failure (HF). Abnormalities in skeletal muscle (SM) metabolism have been identified in patients with HF. However, the underlying mechanisms of IR development in SM in HF are poorly understood. Herein, we hypothesize that HF upregulates miR-133b in SM and in turn alters glucose metabolism and the propensity toward IR. Mitochondria isolated from SM of mice with HF induced by transverse aortic constriction (TAC) showed lower respiration and downregulation of muscle-specific components of the tricarboxylic acid (TCA) cycle, AMP deaminase 1 (AMPD1), and fumarate compared with those from control animals. RNA-Seq and subsequent qPCR validation confirmed upregulation of SM-specific microRNA (miRNA), miR-133b, in TAC versus sham animals. miR-133b overexpression alone resulted in significantly lower mitochondrial respiration, cellular glucose uptake, and glycolysis along with lower ATP production and cellular energy reserve compared with the scramble (Scr) in C2C12 cells. miR-133b binds to the 3'-untranslated region (UTR) of KLF15, the transcription factor for the insulin-sensitive glucose transporter, GLUT4. Overexpression of miR-133b lowers GLUT4 and lowers pAkt in presence of insulin in C2C12 cells. Finally, lowering miR-133b in primary skeletal myocytes isolated from TAC mice using antagomir-133b reversed the changes in KLF15, GLUT4, and AMPD1 compared with the scramble-transfected myocytes. Taken together, these data demonstrate a role for SM miR-133b in altered glucose metabolism in HF and suggest the therapeutic potential in HF to improve glucose uptake and glycolysis by restoring GLUT4 abundance. The data uncover a novel mechanism for IR and ultimately SM metabolic abnormalities in patients with HF.NEW & NOTEWORTHY Heart failure is associated with systemic insulin resistance and abnormalities in glucose metabolism but the underlying mechanisms are poorly understood. In the skeletal muscle, the major peripheral site of glucose utilization, we observe an increase in miR-133b in heart failure mice, which reduces the insulin-sensitive glucose transporter (GLUT4), glucose uptake, and metabolism in C2C12 and in myocytes. The antagomir for miR-133b restores GLUT4 protein and markers of metabolism in skeletal myocytes from heart failure mice demonstrating that miR-133b is an exciting target for systemic insulin resistance in heart failure and an important player in the cross talk between the heart and the periphery in the heart failure syndrome.
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Affiliation(s)
- Fernanda Carrizo Velasquez
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Barbara Roman
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Erick O Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - Michelle K Leppo
- Division of Cardiology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Sharon K Truong
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Charles Steenbergen
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Martin F Schneider
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - Robert G Weiss
- Division of Cardiology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Samarjit Das
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
- Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
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3
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Wang X, Nawaz M, DuPont C, Myers JH, Burke SR, Bannister RA, Foy BD, Voss AA, Rich MM. The role of action potential changes in depolarization-induced failure of excitation contraction coupling in mouse skeletal muscle. eLife 2022; 11:71588. [PMID: 34985413 PMCID: PMC8730720 DOI: 10.7554/elife.71588] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 12/24/2021] [Indexed: 12/24/2022] Open
Abstract
Excitation-contraction coupling (ECC) is the process by which electrical excitation of muscle is converted into force generation. Depolarization of skeletal muscle resting potential contributes to failure of ECC in diseases such as periodic paralysis, intensive care unit acquired weakness and possibly fatigue of muscle during vigorous exercise. When extracellular K+ is raised to depolarize the resting potential, failure of ECC occurs suddenly, over a narrow range of resting potentials. Simultaneous imaging of Ca2+ transients and recording of action potentials (APs) demonstrated failure to generate Ca2+ transients when APs peaked at potentials more negative than -30mV. An AP property that closely correlated with failure of the Ca2+ transient was the integral of AP voltage with respect to time. Simultaneous recording of Ca2+ transients and APs with electrodes separated by 1.6mm revealed AP conduction fails when APs peak below -21mV. We hypothesize propagation of APs and generation of Ca2+ transients are governed by distinct AP properties: AP conduction is governed by AP peak, whereas Ca2+ release from the sarcoplasmic reticulum is governed by AP integral. The reason distinct AP properties may govern distinct steps of ECC is the kinetics of the ion channels involved. Na channels, which govern propagation, have rapid kinetics and are insensitive to AP width (and thus AP integral) whereas Ca2+ release is governed by gating charge movement of Cav1.1 channels, which have slower kinetics such that Ca2+ release is sensitive to AP integral. The quantitative relationships established between resting potential, AP properties, AP conduction and Ca2+ transients provide the foundation for future studies of failure of ECC induced by depolarization of the resting potential.
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Affiliation(s)
- Xueyong Wang
- Wright State University, Department of Neuroscience, Cell Biology, and Physiology, Dayton, United States
| | - Murad Nawaz
- Wright State University, Department of Neuroscience, Cell Biology, and Physiology, Dayton, United States
| | - Chris DuPont
- Wright State University, Department of Neuroscience, Cell Biology, and Physiology, Dayton, United States
| | - Jessica H Myers
- Wright State University, Department of Neuroscience, Cell Biology, and Physiology, Dayton, United States
| | - Steve Ra Burke
- Wright State University, Department of Biological Sciences, Dayton, United States
| | - Roger A Bannister
- University of Maryland School of Medicine, Departments of Pathology/Biochemistry & Molecular Biology, Baltimore, United States
| | - Brent D Foy
- Wright State University, Department of Physics, Dayton, United States
| | - Andrew A Voss
- Wright State University, Department of Biological Sciences, Dayton, United States
| | - Mark M Rich
- Wright State University, Department of Neuroscience, Cell Biology, and Physiology, Dayton, United States
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4
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Voltage sensor movements of Ca V1.1 during an action potential in skeletal muscle fibers. Proc Natl Acad Sci U S A 2021; 118:2026116118. [PMID: 34583989 DOI: 10.1073/pnas.2026116118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2021] [Indexed: 11/18/2022] Open
Abstract
The skeletal muscle L-type Ca2+ channel (CaV1.1) works primarily as a voltage sensor for skeletal muscle action potential (AP)-evoked Ca2+ release. CaV1.1 contains four distinct voltage-sensing domains (VSDs), yet the contribution of each VSD to AP-evoked Ca2+ release remains unknown. To investigate the role of VSDs in excitation-contraction coupling (ECC), we encoded cysteine substitutions on each S4 voltage-sensing segment of CaV1.1, expressed each construct via in vivo gene transfer electroporation, and used in cellulo AP fluorometry to track the movement of each CaV1.1 VSD in skeletal muscle fibers. We first provide electrical measurements of CaV1.1 voltage sensor charge movement in response to an AP waveform. Then we characterize the fluorescently labeled channels' VSD fluorescence signal responses to an AP and compare them with the waveforms of the electrically measured charge movement, the optically measured free myoplasmic Ca2+, and the calculated rate of Ca2+ release from the sarcoplasmic reticulum for an AP, the physiological signal for skeletal muscle fiber activation. A considerable fraction of the fluorescence signal for each VSD occurred after the time of peak Ca2+ release, and even more occurred after the earlier peak of electrically measured charge movement during an AP, and thus could not directly reflect activation of Ca2+ release or charge movement, respectively. However, a sizable fraction of the fluorometric signals for VSDs I, II, and IV, but not VSDIII, overlap the rising phase of charge moved, and even more for Ca2+ release, and thus could be involved in voltage sensor rearrangements or Ca2+ release activation.
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5
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Zhao Z, Liu M, Zhang Y, Liang Y, Ma D, Wang H, Ma Z, Guan S, Wu Z, Chu X, Lin Y, Chu L. Cardioprotective Effect of Monoammonium Glycyrrhizinate Injection Against Myocardial Ischemic Injury in vivo and in vitro: Involvement of Inhibiting Oxidative Stress and Regulating Ca 2+ Homeostasis by L-Type Calcium Channels. DRUG DESIGN DEVELOPMENT AND THERAPY 2020; 14:331-346. [PMID: 32158189 PMCID: PMC6986180 DOI: 10.2147/dddt.s232130] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 01/15/2020] [Indexed: 01/15/2023]
Abstract
Purpose Monoammonium glycyrrhizinate (MAG) is an aglycone of glycyrrhizin that is found in licorice and is often used clinically as an injection to treat liver diseases. However, the effect of MAG injection on cardiac function and its possible cellular mechanisms remain unclear. We explored the protective effects of MAG against myocardial ischemic injury (MII) induced by isoproterenol (ISO), as well as the cellular mechanisms via molecular biology techniques and patch-clamp recording. Methods A rat model of myocardial ischemia injury was induced by administering ISO (85 mg/kg) subcutaneously for 2 consecutive days. ECG, cardiac functional parameters, CK and LDH levels, SOD and GSH activities, MDA concentration, histological myocardium inspection, mitochondria ultrastructure changes, intracellular calcium concentrations were observed. Influences of MAG on ICa-L and contraction in isolated rat myocytes were observed by the patch-clamp technique. Results MAG reduced damage, improved cardiac morphology, inhibited oxidative stress, decreased the generation of reactive oxygen species, and decreased intracellular Ca2+ concentration. Exposure of the rats’ ventricular myocytes to MAG resulted in a concentration-dependent reduction in L-type calcium currents (ICa-L). MAG reduced ICa-L in a consistent and time-dependent fashion with a semi-maximal prohibitive concentration of MAG of 14 μM. MAG also shifted the I-V curve of ICa-L upwards and moved the activation and inactivation curves of ICa-L to the left. Conclusion The findings indicate that MAG injection exerts a protective influence on ISO-induced MII by inhibiting oxidative stress and regulating Ca2+ homeostasis by ICa-L.
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Affiliation(s)
- Zhifeng Zhao
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, People's Republic of China
| | - Miaomiao Liu
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, People's Republic of China
| | - Yuanyuan Zhang
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, People's Republic of China
| | - Yingran Liang
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, People's Republic of China
| | - Donglai Ma
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, People's Republic of China
| | - Hongfang Wang
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, People's Republic of China
| | - Zhihong Ma
- School of Basic Medicine, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, People's Republic of China
| | - Shengjiang Guan
- School of Basic Medicine, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, People's Republic of China
| | - Zhonglin Wu
- The Fourth Hospital of Hebei Medical University, Shijiazhuang 050011, Hebei, People's Republic of China
| | - Xi Chu
- The Fourth Hospital of Hebei Medical University, Shijiazhuang 050011, Hebei, People's Republic of China
| | - Yue Lin
- School of Basic Medicine, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, People's Republic of China
| | - Li Chu
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang 050200, Hebei, People's Republic of China.,Hebei Key Laboratory of Integrative Medicine on Liver-Kidney Patterns, Shijiazhuang 050200, Hebei, People's Republic of China
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6
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Banks Q, Pratt SJP, Iyer SR, Lovering RM, Hernández-Ochoa EO, Schneider MF. Optical Recording of Action Potential Initiation and Propagation in Mouse Skeletal Muscle Fibers. Biophys J 2018; 115:2127-2140. [PMID: 30448039 PMCID: PMC6289662 DOI: 10.1016/j.bpj.2018.10.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 10/18/2018] [Accepted: 10/24/2018] [Indexed: 01/29/2023] Open
Abstract
Skeletal muscle fibers have been used to examine a variety of cellular functions and pathologies. Among other parameters, skeletal muscle action potential (AP) propagation has been measured to assess the integrity and function of skeletal muscle. In this work, we utilize 1-(3-sulfonatopropyl)-4[β[2-(Di-n-octylamino)-6-naphtyl]vinyl]pyridinium betaine, a potentiometric dye, and mag-fluo-4, a low-affinity intracellular Ca2+indicator, to noninvasively and reliably measure AP conduction velocity in skeletal muscle. We used remote extracellular bipolar electrodes to generate an alternating polarity electric field that initiates an AP at either end of the fiber. Using enzymatically dissociated flexor digitorum brevis (FDB) fibers and high-speed line scans, we determine the conduction velocity to be ∼0.4 m/s. We applied these methodologies to FDB fibers under elevated extracellular potassium conditions and confirmed that the conduction velocity is significantly reduced in elevated [K+]o. Because our recorded velocities for FDB fibers were much slower than previously reported for other muscle groups, we compared the conduction velocity in FDB fibers to that of extensor digitorum longus (EDL) fibers and measured a significantly faster velocity in EDL fibers than FDB fibers. As a basis for this difference in conduction velocity, we found a similarly higher level of expression of Na+ channels in EDL than in FDB fibers. In addition to measuring the conduction velocity, we can also measure the passive electrotonic potentials elicited by pulses by applying tetrodotoxin and have constructed a circuit model of a skeletal muscle fiber to predict passive polarization of the fiber by the field stimuli. Our predictions from the model fiber closely resemble the recordings acquired from in vitro assays. With these techniques, we can examine how various pathologies and mutations affect skeletal muscle AP propagation. Our work demonstrates the utility of using 1-(3-sulfonatopropyl)-4[β[2-(Di-n-octylamino)-6-naphtyl]vinyl]pyridinium betaine or mag-fluo-4 to noninvasively measure AP initiation and conduction.
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Affiliation(s)
- Quinton Banks
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Stephen Joseph Paul Pratt
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Shama Rajan Iyer
- Department of Orthopedics, University of Maryland School of Medicine, Baltimore, Maryland
| | | | - Erick Omar Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Martin Frederick Schneider
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland.
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7
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Hernández‐Ochoa EO, Melville Z, Vanegas C, Varney KM, Wilder PT, Melzer W, Weber DJ, Schneider MF. Loss of S100A1 expression leads to Ca 2+ release potentiation in mutant mice with disrupted CaM and S100A1 binding to CaMBD2 of RyR1. Physiol Rep 2018; 6:e13822. [PMID: 30101473 PMCID: PMC6087734 DOI: 10.14814/phy2.13822] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 11/24/2022] Open
Abstract
Calmodulin (CaM) and S100A1 fine-tune skeletal muscle Ca2+ release via opposite modulation of the ryanodine receptor type 1 (RyR1). Binding to and modulation of RyR1 by CaM and S100A1 occurs predominantly at the region ranging from amino acid residue 3614-3640 of RyR1 (here referred to as CaMBD2). Using synthetic peptides, it has been shown that CaM binds to two additional regions within the RyR1, specifically residues 1975-1999 and 4295-4325 (CaMBD1 and CaMBD3, respectively). Because S100A1 typically binds to similar motifs as CaM, we hypothesized that S100A1 could also bind to CaMBD1 and CaMBD3. Our goals were: (1) to establish whether S100A1 binds to synthetic peptides containing CaMBD1 and CaMBD3 using isothermal calorimetry (ITC), and (2) to identify whether S100A1 and CaM modulate RyR1 Ca2+ release activation via sites other than CaMBD2 in RyR1 in its native cellular context. We developed the mouse model (RyR1D-S100A1KO), which expresses point mutation RyR1-L3625D (RyR1D) that disrupts the modulation of RyR1 by CaM and S100A1 at CaMBD2 and also lacks S100A1 (S100A1KO). ITC assays revealed that S100A1 binds with different affinities to CaMBD1 and CaMBD3. Using high-speed Ca2+ imaging and a model for Ca2+ binding and transport, we show that the RyR1D-S100A1KO muscle fibers exhibit a modest but significant increase in myoplasmic Ca2+ transients and enhanced Ca2+ release flux following field stimulation when compared to fibers from RyR1D mice, which were used as controls to eliminate any effect of binding at CaMBD2, but with preserved S100A1 expression. Our results suggest that S100A1, similar to CaM, binds to CaMBD1 and CaMBD3 within the RyR1, but that CaMBD2 appears to be the primary site of RyR1 regulation by CaM and S100A1.
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Affiliation(s)
- Erick O. Hernández‐Ochoa
- Department of Biochemistry and Molecular BiologyUniversity of Maryland School of MedicineBaltimoreMaryland
| | - Zephan Melville
- Department of Biochemistry and Molecular BiologyUniversity of Maryland School of MedicineBaltimoreMaryland
| | - Camilo Vanegas
- Department of Biochemistry and Molecular BiologyUniversity of Maryland School of MedicineBaltimoreMaryland
| | - Kristen M. Varney
- Department of Biochemistry and Molecular BiologyUniversity of Maryland School of MedicineBaltimoreMaryland
- Center for Biomolecular Therapeutics (CBT)University of Maryland School of MedicineMaryland
| | - Paul T. Wilder
- Department of Biochemistry and Molecular BiologyUniversity of Maryland School of MedicineBaltimoreMaryland
- Center for Biomolecular Therapeutics (CBT)University of Maryland School of MedicineMaryland
| | - Werner Melzer
- Institute of Applied PhysiologyUlm UniversityUlmGermany
| | - David J. Weber
- Department of Biochemistry and Molecular BiologyUniversity of Maryland School of MedicineBaltimoreMaryland
- Center for Biomolecular Therapeutics (CBT)University of Maryland School of MedicineMaryland
| | - Martin F. Schneider
- Department of Biochemistry and Molecular BiologyUniversity of Maryland School of MedicineBaltimoreMaryland
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8
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Arcaro CA, Assis RP, Zanon NM, Paula-Gomes S, Navegantes LCC, Kettelhut IC, Brunetti IL, Baviera AM. Involvement of cAMP/EPAC/Akt signaling in the antiproteolytic effects of pentoxifylline on skeletal muscles of diabetic rats. J Appl Physiol (1985) 2017; 124:704-716. [PMID: 29357512 DOI: 10.1152/japplphysiol.00499.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Advances in the knowledge of the mechanisms controlling protein breakdown in skeletal muscles have allowed the exploration of new options for treating muscle-wasting conditions. Pentoxifylline (PTX), a nonselective phosphodiesterase (PDE) inhibitor, attenuates the loss of muscle mass during catabolic conditions, mainly via inhibiting protein breakdown. The aim of this study was to explore the mechanisms by which PTX inhibits proteolysis in the soleus and extensor digitorum longus (EDL) muscles of streptozotocin-induced diabetic rats. The levels of atrogin-1 and muscle RING finger-1 were decreased, as were the activities of caspase-3 (EDL) and calpains (soleus and EDL), in diabetic rats treated with PTX, which at least partly explains the drop in the ubiquitin conjugate (EDL) levels and in proteasome activity (soleus and EDL). Treatment with PTX decreased PDE activity and increased cAMP content in muscles of diabetic rats; moreover, it also increased both the protein levels of exchange protein directly activated by cAMP (EPAC, a cAMP effector) and the phosphorylation of Akt. The loss of muscle mass was practically prevented in diabetic rats treated with PTX. These findings advance our understanding of the mechanisms underlying the antiproteolytic effects of PTX and suggest the use of PDE inhibitors as a strategy to activate cAMP signaling, which is emerging as a promising target for treating muscle mass loss during atrophic conditions. NEW & NOTEWORTHY cAMP signaling has been explored as a strategy to attenuate skeletal muscle atrophies. Therefore, in addition to β2AR agonists, phosphodiesterase inhibitors such as pentoxifylline (PTX) can be an interesting option. This study advances the understanding of the mechanisms related to the antiproteolytic effects of PTX on skeletal muscles of diabetic rats, which involve the activation of both exchange protein directly activated by cAMP and Akt effectors, inhibiting the expression of atrogenes and calpain/caspase-3-proteolytic machinery.
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Affiliation(s)
- Carlos Alberto Arcaro
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University, Araraquara, University of São Paulo , São Paulo , Brazil
| | - Renata Pires Assis
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University, Araraquara, University of São Paulo , São Paulo , Brazil
| | - Neusa Maria Zanon
- Department of Physiology, University of São Paulo, Ribeirão Preto Medical School , Ribeirão Preto, São Paulo , Brazil
| | - Silvia Paula-Gomes
- Department of Biochemistry/Immunology, University of São Paulo, Ribeirão Preto Medical School , Ribeirão Preto, São Paulo , Brazil
| | | | - Isis Carmo Kettelhut
- Department of Physiology, University of São Paulo, Ribeirão Preto Medical School , Ribeirão Preto, São Paulo , Brazil.,Department of Biochemistry/Immunology, University of São Paulo, Ribeirão Preto Medical School , Ribeirão Preto, São Paulo , Brazil
| | - Iguatemy Lourenço Brunetti
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University, Araraquara, University of São Paulo , São Paulo , Brazil
| | - Amanda Martins Baviera
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University, Araraquara, University of São Paulo , São Paulo , Brazil
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9
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Melville Z, Hernández-Ochoa EO, Pratt SJP, Liu Y, Pierce AD, Wilder PT, Adipietro KA, Breysse DH, Varney KM, Schneider MF, Weber DJ. The Activation of Protein Kinase A by the Calcium-Binding Protein S100A1 Is Independent of Cyclic AMP. Biochemistry 2017; 56:2328-2337. [PMID: 28409622 PMCID: PMC5415871 DOI: 10.1021/acs.biochem.7b00117] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Biochemical
and structural studies demonstrate that S100A1 is involved
in a Ca2+-dependent interaction with the type 2α
and type 2β regulatory subunits of protein kinase A (PKA) (RIIα
and RIIβ) to activate holo-PKA. The interaction was specific
for S100A1 because other calcium-binding proteins (i.e., S100B and
calmodulin) had no effect. Likewise, a role for S100A1
in PKA-dependent signaling was established because the PKA-dependent
subcellular redistribution of HDAC4 was abolished in cells derived
from S100A1 knockout mice. Thus, the Ca2+-dependent interaction
between S100A1 and the type 2 regulatory subunits represents a novel
mechanism that provides a link between Ca2+ and PKA signaling,
which is important for the regulation of gene expression in skeletal
muscle via HDAC4 cytosolic–nuclear trafficking.
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Affiliation(s)
- Zephan Melville
- Department of Biochemistry and Molecular Biology and ‡Center for Biomolecular Therapeutics, University of Maryland School of Medicine , 108 North Greene Street, Baltimore, Maryland 21201, United States
| | - Erick O Hernández-Ochoa
- Department of Biochemistry and Molecular Biology and ‡Center for Biomolecular Therapeutics, University of Maryland School of Medicine , 108 North Greene Street, Baltimore, Maryland 21201, United States
| | - Stephen J P Pratt
- Department of Biochemistry and Molecular Biology and ‡Center for Biomolecular Therapeutics, University of Maryland School of Medicine , 108 North Greene Street, Baltimore, Maryland 21201, United States
| | - Yewei Liu
- Department of Biochemistry and Molecular Biology and ‡Center for Biomolecular Therapeutics, University of Maryland School of Medicine , 108 North Greene Street, Baltimore, Maryland 21201, United States
| | - Adam D Pierce
- Department of Biochemistry and Molecular Biology and ‡Center for Biomolecular Therapeutics, University of Maryland School of Medicine , 108 North Greene Street, Baltimore, Maryland 21201, United States
| | - Paul T Wilder
- Department of Biochemistry and Molecular Biology and ‡Center for Biomolecular Therapeutics, University of Maryland School of Medicine , 108 North Greene Street, Baltimore, Maryland 21201, United States
| | - Kaylin A Adipietro
- Department of Biochemistry and Molecular Biology and ‡Center for Biomolecular Therapeutics, University of Maryland School of Medicine , 108 North Greene Street, Baltimore, Maryland 21201, United States
| | - Daniel H Breysse
- Department of Biochemistry and Molecular Biology and ‡Center for Biomolecular Therapeutics, University of Maryland School of Medicine , 108 North Greene Street, Baltimore, Maryland 21201, United States
| | - Kristen M Varney
- Department of Biochemistry and Molecular Biology and ‡Center for Biomolecular Therapeutics, University of Maryland School of Medicine , 108 North Greene Street, Baltimore, Maryland 21201, United States
| | - Martin F Schneider
- Department of Biochemistry and Molecular Biology and ‡Center for Biomolecular Therapeutics, University of Maryland School of Medicine , 108 North Greene Street, Baltimore, Maryland 21201, United States
| | - David J Weber
- Department of Biochemistry and Molecular Biology and ‡Center for Biomolecular Therapeutics, University of Maryland School of Medicine , 108 North Greene Street, Baltimore, Maryland 21201, United States
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Hernández-Ochoa EO, Banks Q, Schneider MF. Acute Elevated Glucose Promotes Abnormal Action Potential-Induced Ca 2+ Transients in Cultured Skeletal Muscle Fibers. J Diabetes Res 2017; 2017:1509048. [PMID: 28835899 PMCID: PMC5557004 DOI: 10.1155/2017/1509048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/01/2017] [Accepted: 06/22/2017] [Indexed: 12/13/2022] Open
Abstract
A common comorbidity of diabetes is skeletal muscle dysfunction, which leads to compromised physical function. Previous studies of diabetes in skeletal muscle have shown alterations in excitation-contraction coupling (ECC)-the sequential link between action potentials (AP), intracellular Ca2+ release, and the contractile machinery. Yet, little is known about the impact of acute elevated glucose on the temporal properties of AP-induced Ca2+ transients and ionic underlying mechanisms that lead to muscle dysfunction. Here, we used high-speed confocal Ca2+ imaging to investigate the temporal properties of AP-induced Ca2+ transients, an intermediate step of ECC, using an acute in cellulo model of uncontrolled hyperglycemia (25 mM, 48 h.). Control and elevated glucose-exposed muscle fibers cultured for five days displayed four distinct patterns of AP-induced Ca2+ transients (phasic, biphasic, phasic-delayed, and phasic-slow decay); most control muscle fibers show phasic AP-induced Ca2+ transients, while most fibers exposed to elevated D-glucose displayed biphasic Ca2+ transients upon single field stimulation. We hypothesize that these changes in the temporal profile of the AP-induced Ca2+ transients are due to changes in the intrinsic excitable properties of the muscle fibers. We propose that these changes accompany early stages of diabetic myopathy.
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Affiliation(s)
- Erick O. Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- *Erick O. Hernández-Ochoa:
| | - Quinton Banks
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Martin F. Schneider
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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