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Wang Y, Chen Y, Li Z, Tang L, Wen D, Wu Y, Guo Z. Electroacupuncture enhances cerebral blood perfusion by inhibiting HIF-1α in rat subarachnoid hemorrhage. Brain Res 2024; 1839:149010. [PMID: 38763503 DOI: 10.1016/j.brainres.2024.149010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/06/2024] [Accepted: 05/16/2024] [Indexed: 05/21/2024]
Abstract
OBJECTIVE Cerebral blood perfusion (CBP) reduction is a prevalent complication following subarachnoid hemorrhage (SAH) in clinical practice, often associated with long-term cognitive impairment and prognosis. Electroacupuncture (EA), a widely utilized traditional Chinese therapy for central nervous system disorders, has demonstrated promising therapeutic effects. This study aims to investigate the therapeutic potential of EA in restoring CBP in SAH rats and to explore the mechanisms involving HIF-1α in this process. METHODS Rats were randomly assigned to one of five groups, including Sham, SAH, EA, EA + Saline, and EA + dimethyloxallyl glycine (DMOG) groups. EA treatment was administered for 10 min daily, while DMOG were intraperitoneally injected. Behavioral tests, cerebral blood flow monitoring, vascular thickness measurement, western blotting, and immunofluorescence staining were conducted to assess the therapeutic effects of EA on cerebral blood flow. RESULTS SAH resulted in elevated levels of HIF-1α, endothelin (ET), ICAM-1, P-SELECTIN, E-SELECTIN, and decreased level of eNOS in the brain. This led to cerebral vasospasm, decreased CBF, and cognitive deficits in the rat SAH model. EA intervention downregulated the expression of HIF-1α, ET, ICAM-1, P-SELECTIN, and E-SELECTIN, while increasing eNOS expression. This alleviated cerebral vasospasm, restored CBF, and improved cognitive function. However, the administration of the HIF-1α stabilizer (DMOG) counteracted the therapeutic effects of EA. CONCLUSION EA promotes the recovery of cerebral blood flow after SAH injury, attenuates cerebral vasospasm, and accelerates the recovery of cognitive dysfunction, and its mechanism of action may be related to the inhibition of the HIF-1α signaling pathway.
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Affiliation(s)
- Yingwen Wang
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Yu Chen
- Department of Rehabilitation, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China
| | - Zhao Li
- Emergency Department, Chengdu First People's Hospital, Chengdu, Sichuan Province, China.
| | - Liuyang Tang
- Department of Neurosurgery, The People's Hospital of Qijiang District, 401420, China
| | - Daochen Wen
- Department of Neurosurgery, Xuanhan County People's Hospital, Dazhou, China.
| | - Yue Wu
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.
| | - Zongduo Guo
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.
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2
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Davis MJ, Zawieja SD. Pacemaking in the lymphatic system. J Physiol 2024. [PMID: 38520402 DOI: 10.1113/jp284752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 02/08/2024] [Indexed: 03/25/2024] Open
Abstract
Lymphatic collecting vessels exhibit spontaneous phasic contractions that are critical for lymph propulsion and tissue fluid homeostasis. This rhythmic activity is driven by action potentials conducted across the lymphatic muscle cell (LMC) layer to produce entrained contractions. The contraction frequency of a lymphatic collecting vessel displays exquisite mechanosensitivity, with a dynamic range from <1 to >20 contractions per minute. A myogenic pacemaker mechanism intrinsic to the LMCs was initially postulated to account for pressure-dependent chronotropy. Further interrogation into the cellular constituents of the lymphatic vessel wall identified non-muscle cell populations that shared some characteristics with interstitial cells of Cajal, which have pacemaker functions in the gastrointestinal and lower urinary tracts, thus raising the possibility of a non-muscle cell pacemaker. However, recent genetic knockout studies in mice support LMCs and a myogenic origin of the pacemaker activity. LMCs exhibit stochastic, but pressure-sensitive, sarcoplasmic reticulum calcium release (puffs and waves) from IP3R1 receptors, which couple to the calcium-activated chloride channel Anoctamin 1, causing depolarisation. The resulting electrical activity integrates across the highly coupled lymphatic muscle electrical syncytia through connexin 45 to modulate diastolic depolarisation. However, multiple other cation channels may also contribute to the ionic pacemaking cycle. Upon reaching threshold, a voltage-gated calcium channel-dependent action potential fires, resulting in a nearly synchronous calcium global calcium flash within the LMC layer to drive an entrained contraction. This review summarizes the key ion channels potentially responsible for the pressure-dependent chronotropy of lymphatic collecting vessels and various mechanisms of IP3R1 regulation that could contribute to frequency tuning.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, USA
| | - Scott D Zawieja
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, USA
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3
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Pal S, Bagchi AK, Stolarz AJ. Real-Time Evaluation of Absolute, Cytosolic, Free Ca2+ and Corresponding Contractility in Isolated, Pressurized Lymph Vessels. J Vis Exp 2024:10.3791/66535. [PMID: 38587372 PMCID: PMC11164129 DOI: 10.3791/66535] [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] [Indexed: 04/09/2024] Open
Abstract
The lymphatic vasculature, now often referred to as "the third circulation," is located in many vital organ systems. A principal mechanical function of the lymphatic vasculature is to return fluid from extracellular spaces back to the central venous ducts. Lymph transport is mediated by spontaneous rhythmic contractions of lymph vessels (LVs). LV contractions are largely regulated by the cyclic rise and fall of cytosolic, free calcium ([Ca2+]i). This paper presents a method to concurrently calculate changes in absolute concentrations of [Ca2+]i and vessel contractility/rhythmicity in real time in isolated, pressurized LVs. Using isolated rat mesenteric LVs, we studied changes in [Ca2+]i and contractility/rhythmicity in response to drug addition. Isolated LVs were loaded with the ratiometric Ca2+-sensing indicator Fura-2AM, and video microscopy coupled with edge-detection software was used to capture [Ca2+]i and diameter measurements continuously in real time. The Fura-2AM signal from each LV was calibrated to the minimum and maximum signal for each vessel and used to calculate absolute [Ca2+]i. Diameter measurements were used to calculate contractile parameters (amplitude, end diastolic diameter, end systolic diameter, calculated flow) and rhythmicity (frequency, contraction time, relaxation time) and correlated with absolute [Ca2+]i measurements.
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Affiliation(s)
- Soumiya Pal
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences
| | - Ashim K Bagchi
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences
| | - Amanda J Stolarz
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences;
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Zawieja SD, Pea GA, Broyhill SE, Patro A, Bromert KH, Li M, Norton CE, Castorena-Gonzalez JA, Hancock EJ, Bertram CD, Davis MJ. IP3R1 underlies diastolic ANO1 activation and pressure-dependent chronotropy in lymphatic collecting vessels. J Gen Physiol 2023; 155:e202313358. [PMID: 37851027 PMCID: PMC10585095 DOI: 10.1085/jgp.202313358] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 08/11/2023] [Accepted: 09/22/2023] [Indexed: 10/19/2023] Open
Abstract
Pressure-dependent chronotropy of murine lymphatic collecting vessels relies on the activation of the Ca2+-activated chloride channel encoded by Anoctamin 1 (Ano1) in lymphatic muscle cells. Genetic ablation or pharmacological inhibition of ANO1 results in a significant reduction in basal contraction frequency and essentially complete loss of pressure-dependent frequency modulation by decreasing the rate of the diastolic depolarization phase of the ionic pacemaker in lymphatic muscle cells (LMCs). Oscillating Ca2+ release from sarcoendoplasmic reticulum Ca2+ channels has been hypothesized to drive ANO1 activity during diastole, but the source of Ca2+ for ANO1 activation in smooth muscle remains unclear. Here, we investigated the role of the inositol triphosphate receptor 1 (Itpr1; Ip3r1) in this process using pressure myography, Ca2+ imaging, and membrane potential recordings in LMCs of ex vivo pressurized inguinal-axillary lymphatic vessels from control or Myh11CreERT2;Ip3r1fl/fl (Ip3r1ismKO) mice. Ip3r1ismKO vessels had significant reductions in contraction frequency and tone but an increased contraction amplitude. Membrane potential recordings from LMCs of Ip3r1ismKO vessels revealed a depressed diastolic depolarization rate and an elongation of the plateau phase of the action potential (AP). Ca2+ imaging of LMCs using the genetically encoded Ca2+ sensor GCaMP6f demonstrated an elongation of the Ca2+ flash associated with an AP-driven contraction. Critically, diastolic subcellular Ca2+ transients were absent in LMCs of Ip3r1ismKO mice, demonstrating the necessity of IP3R1 activity in controlling ANO1-mediated diastolic depolarization. These findings indicate a critical role for IP3R1 in lymphatic vessel pressure-dependent chronotropy and contractile regulation.
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Affiliation(s)
- Scott D. Zawieja
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Grace A. Pea
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Sarah E. Broyhill
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Advaya Patro
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Karen H. Bromert
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Min Li
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Charles E. Norton
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | | | - Edward J. Hancock
- School of Mathematics and Statistics, University of Sydney, Sydney, Australia
| | | | - Michael J. Davis
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
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Breslin JW. Lymphatic Clearance and Pump Function. Cold Spring Harb Perspect Med 2023; 13:cshperspect.a041187. [PMID: 35667711 PMCID: PMC9899645 DOI: 10.1101/cshperspect.a041187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Lymphatic vessels have an active role in draining excess interstitial fluid from organs and serving as conduits for immune cell trafficking to lymph nodes. In the central circulation, the force needed to propel blood forward is generated by the heart. In contrast, lymphatic vessels rely on intrinsic vessel contractions in combination with extrinsic forces for lymph propulsion. The intrinsic pumping features phasic contractions generated by lymphatic smooth muscle. Periodic, bicuspid valves composed of endothelial cells prevent backflow of lymph. This work provides a brief overview of lymph transport, including initial lymph formation along with cellular and molecular mechanisms controlling lymphatic vessel pumping.
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Affiliation(s)
- Jerome W Breslin
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, USA
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6
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Pal S, Rahman J, Mu S, Rusch NJ, Stolarz AJ. Drug-Related Lymphedema: Mysteries, Mechanisms, and Potential Therapies. Front Pharmacol 2022; 13:850586. [PMID: 35308247 PMCID: PMC8930849 DOI: 10.3389/fphar.2022.850586] [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: 01/07/2022] [Accepted: 02/11/2022] [Indexed: 11/13/2022] Open
Abstract
The lymphatic circulation is an important component of the circulatory system in humans, playing a critical role in the transport of lymph fluid containing proteins, white blood cells, and lipids from the interstitial space to the central venous circulation. The efficient transport of lymph fluid critically relies on the rhythmic contractions of collecting lymph vessels, which function to “pump” fluid in the distal to proximal direction through the lymphatic circulation with backflow prevented by the presence of valves. When rhythmic contractions are disrupted or valves are incompetent, the loss of lymph flow results in fluid accumulation in the interstitial space and the development of lymphedema. There is growing recognition that many pharmacological agents modify the activity of ion channels and other protein structures in lymph muscle cells to disrupt the cyclic contraction and relaxation of lymph vessels, thereby compromising lymph flow and predisposing to the development of lymphedema. The effects of different medications on lymph flow can be understood by appreciating the intricate intracellular calcium signaling that underlies the contraction and relaxation cycle of collecting lymph vessels. For example, voltage-sensitive calcium influx through long-lasting (“L-type”) calcium channels mediates the rise in cytosolic calcium concentration that triggers lymph vessel contraction. Accordingly, calcium channel antagonists that are mainstay cardiovascular medications, attenuate the cyclic influx of calcium through L-type calcium channels in lymph muscle cells, thereby disrupting rhythmic contractions and compromising lymph flow. Many other classes of medications also may contribute to the formation of lymphedema by impairing lymph flow as an off-target effect. The purpose of this review is to evaluate the evidence regarding potential mechanisms of drug-related lymphedema with an emphasis on common medications administered to treat cardiovascular diseases, metabolic disorders, and cancer. Additionally, although current pharmacological approaches used to alleviate lymphedema are largely ineffective, efforts are mounting to arrive at a deeper understanding of mechanisms that regulate lymph flow as a strategy to identify novel anti-lymphedema medications. Accordingly, this review also will provide information on studies that have explored possible anti-lymphedema therapeutics.
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Affiliation(s)
- Soumiya Pal
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Jenat Rahman
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Shengyu Mu
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Nancy J. Rusch
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Amanda J. Stolarz
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR, United States
- *Correspondence: Amanda J. Stolarz,
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Russell PS, Hong J, Trevaskis NL, Windsor JA, Martin ND, Phillips ARJ. Lymphatic Contractile Function: A Comprehensive Review of Drug Effects and Potential Clinical Application. Cardiovasc Res 2021; 118:2437-2457. [PMID: 34415332 DOI: 10.1093/cvr/cvab279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 08/18/2021] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND The lymphatic system and the cardiovascular system work together to maintain body fluid homeostasis. Despite that, the lymphatic system has been relatively neglected as a potential drug target and a source of adverse effects from cardiovascular drugs. Like the heart, the lymphatic vessels undergo phasic contractions to promote lymph flow against a pressure gradient. Dysfunction or failure of the lymphatic pump results in fluid imbalance and tissue oedema. While this can due to drug effects, it is also a feature of breast cancer-associated lymphoedema, chronic venous insufficiency, congestive heart failure and acute systemic inflammation. There are currently no specific drug treatments for lymphatic pump dysfunction in clinical use despite the wealth of data from pre-clinical studies. AIM To identify (1) drugs with direct effects on lymphatic tonic and phasic contractions with potential for clinical application, and (2) drugs in current clinical use that have a positive or negative side effect on lymphatic function. METHODS We comprehensively reviewed all studies that tested the direct effect of a drug on the contractile function of lymphatic vessels. RESULTS Of the 208 drugs identified from 193 studies, about a quarter had only stimulatory effects on lymphatic tone, contraction frequency and/or contraction amplitude. Of FDA-approved drugs, there were 14 that increased lymphatic phasic contractile function. The most frequently used class of drug with inhibitory effects on lymphatic pump function were the calcium channels blockers. CONCLUSION This review highlights the opportunity for specific drug treatments of lymphatic dysfunction in various disease states and for avoiding adverse drug effects on lymphatic contractile function.
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Affiliation(s)
- Peter S Russell
- Applied Surgery and Metabolism Laboratory, School of Biological Sciences, University of Auckland, Auckland, New Zealand.,Surgical and Translational Research Centre, Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Jiwon Hong
- Applied Surgery and Metabolism Laboratory, School of Biological Sciences, University of Auckland, Auckland, New Zealand.,Surgical and Translational Research Centre, Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Natalie L Trevaskis
- Monash Institute of Pharmaceutical Sciences, Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Melbourne, Australia
| | - John A Windsor
- Surgical and Translational Research Centre, Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Niels D Martin
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Anthony R J Phillips
- Applied Surgery and Metabolism Laboratory, School of Biological Sciences, University of Auckland, Auckland, New Zealand.,Surgical and Translational Research Centre, Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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8
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Van S, Pal S, Garner BR, Steed K, Sridharan V, Mu S, Rusch NJ, Stolarz AJ. Dantrolene Prevents the Lymphostasis Caused by Doxorubicin in the Rat Mesenteric Circulation. Front Pharmacol 2021; 12:727526. [PMID: 34483938 PMCID: PMC8415554 DOI: 10.3389/fphar.2021.727526] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 08/05/2021] [Indexed: 11/29/2022] Open
Abstract
Background and Purpose: Doxorubicin (DOX) is a risk factor for arm lymphedema in breast cancer patients. We reported that DOX opens ryanodine receptors (RYRs) to enact "calcium leak," which disrupts the rhythmic contractions of lymph vessels (LVs) to attenuate lymph flow. Here, we evaluated whether dantrolene, a clinically available RYR1 subtype antagonist, prevents the detrimental effects of DOX on lymphatic function. Experimental Approach: Isolated rat mesenteric LVs were cannulated, pressurized (4-5 mm Hg) and equilibrated in physiological salt solution and Fura-2AM. Video microscopy recorded changes in diameter and Fura-2AM fluorescence tracked cytosolic free calcium ([Ca2+ i]). High-speed in vivo microscopy assessed mesenteric lymph flow in anesthetized rats. Flow cytometry evaluated RYR1 expression in freshly isolated mesenteric lymphatic muscle cells (LMCs). Key Results: DOX (10 μmol/L) increased resting [Ca2+ i] by 17.5 ± 3.7% in isolated LVs (n = 11). The rise in [Ca2+ i] was prevented by dantrolene (3 μmol/L; n = 10). A single rapid infusion of DOX (10 mg/kg i.v.) reduced positive volumetric lymph flow to 29.7 ± 10.8% (n = 7) of baseline in mesenteric LVs in vivo. In contrast, flow in LVs superfused with dantrolene (10 μmol/L) only decreased to 76.3 ± 14.0% (n = 7) of baseline in response to DOX infusion. Subsequently, expression of the RYR1 subtype protein as the presumed dantrolene binding site was confirm in isolated mesenteric LMCs by flow cytometry. Conclusion and Implications: We conclude that dantrolene attenuates the acute impairment of lymph flow by DOX and suggest that its prophylactic use in patients subjected to DOX chemotherapy may lower lymphedema risk.
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Affiliation(s)
- Serena Van
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Soumiya Pal
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Brittney R. Garner
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Kate Steed
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Vijayalakshmi Sridharan
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Shengyu Mu
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Nancy J. Rusch
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Amanda J. Stolarz
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR, United States
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, United States
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Stolarz AJ, Sarimollaoglu M, Marecki JC, Fletcher TW, Galanzha EI, Rhee SW, Zharov VP, Klimberg VS, Rusch NJ. Doxorubicin Activates Ryanodine Receptors in Rat Lymphatic Muscle Cells to Attenuate Rhythmic Contractions and Lymph Flow. J Pharmacol Exp Ther 2019; 371:278-289. [PMID: 31439806 DOI: 10.1124/jpet.119.257592] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 08/09/2019] [Indexed: 11/22/2022] Open
Abstract
Doxorubicin is a risk factor for secondary lymphedema in cancer patients exposed to surgery or radiation. The risk is presumed to relate to its cytotoxicity. However, the present study provides initial evidence that doxorubicin directly inhibits lymph flow and this action appears distinct from its cytotoxic activity. We used real-time edge detection to track diameter changes in isolated rat mesenteric lymph vessels. Doxorubicin (0.5-20 μmol/l) progressively constricted lymph vessels and inhibited rhythmic contractions, reducing flow to 24.2% ± 7.7% of baseline. The inhibition of rhythmic contractions by doxorubicin paralleled a tonic rise in cytosolic Ca2+ concentration in lymphatic muscle cells, which was prevented by pharmacological antagonism of ryanodine receptors. Washout of doxorubicin partially restored lymph vessel contractions, implying a pharmacological effect. Subsequently, high-speed optical imaging was used to assess the effect of doxorubicin on rat mesenteric lymph flow in vivo. Superfusion of doxorubicin (0.05-10 μmol/l) maximally reduced volumetric lymph flow to 34% ± 11.6% of baseline. Likewise, doxorubicin (10 mg/kg) administered intravenously to establish clinically achievable plasma concentrations also maximally reduced volumetric lymph flow to 40.3% ± 6.0% of initial values. Our findings reveal that doxorubicin at plasma concentrations achieved during chemotherapy opens ryanodine receptors to induce "calcium leak" from the sarcoplasmic reticulum in lymphatic muscle cells and reduces lymph flow, an event linked to lymph vessel damage and the development of lymphedema. These results infer that pharmacological block of ryanodine receptors in lymphatic smooth muscle cells may mitigate secondary lymphedema in cancer patients subjected to doxorubicin chemotherapy. SIGNIFICANCE STATEMENT: Doxorubicin directly inhibits the rhythmic contractions of collecting lymph vessels and reduces lymph flow as a possible mechanism of secondary lymphedema, which is associated with the administration of anthracycline-based chemotherapy. The inhibitory effects of doxorubicin on rhythmic contractions and flow in isolated lymph vessels were prevented by pharmacological block of ryanodine receptors, thereby identifying the ryanodine receptor family of proteins as potential therapeutic targets for the development of new antilymphedema medications.
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Affiliation(s)
- Amanda J Stolarz
- Department of Pharmacology and Toxicology, College of Medicine (A.J.S., T.W.F., S.W.R., N.J.R.) and Department of Biochemistry and Molecular Biology, College of Medicine (J.C.M.), Arkansas Nanomedicine Center, College of Medicine (M.S., V.P.Z.), Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), and Laboratory of Lymphatic Research, Diagnosis and Therapy (E.I.G.), University of Arkansas for Medical Sciences, Little Rock, Arkansas; Division of Surgical Oncology, Department of Surgery, University of Texas Medical Branch, Galveston, Texas, and MD Anderson Cancer Center Houston, Texas (V.S.K.)
| | - Mustafa Sarimollaoglu
- Department of Pharmacology and Toxicology, College of Medicine (A.J.S., T.W.F., S.W.R., N.J.R.) and Department of Biochemistry and Molecular Biology, College of Medicine (J.C.M.), Arkansas Nanomedicine Center, College of Medicine (M.S., V.P.Z.), Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), and Laboratory of Lymphatic Research, Diagnosis and Therapy (E.I.G.), University of Arkansas for Medical Sciences, Little Rock, Arkansas; Division of Surgical Oncology, Department of Surgery, University of Texas Medical Branch, Galveston, Texas, and MD Anderson Cancer Center Houston, Texas (V.S.K.)
| | - John C Marecki
- Department of Pharmacology and Toxicology, College of Medicine (A.J.S., T.W.F., S.W.R., N.J.R.) and Department of Biochemistry and Molecular Biology, College of Medicine (J.C.M.), Arkansas Nanomedicine Center, College of Medicine (M.S., V.P.Z.), Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), and Laboratory of Lymphatic Research, Diagnosis and Therapy (E.I.G.), University of Arkansas for Medical Sciences, Little Rock, Arkansas; Division of Surgical Oncology, Department of Surgery, University of Texas Medical Branch, Galveston, Texas, and MD Anderson Cancer Center Houston, Texas (V.S.K.)
| | - Terry W Fletcher
- Department of Pharmacology and Toxicology, College of Medicine (A.J.S., T.W.F., S.W.R., N.J.R.) and Department of Biochemistry and Molecular Biology, College of Medicine (J.C.M.), Arkansas Nanomedicine Center, College of Medicine (M.S., V.P.Z.), Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), and Laboratory of Lymphatic Research, Diagnosis and Therapy (E.I.G.), University of Arkansas for Medical Sciences, Little Rock, Arkansas; Division of Surgical Oncology, Department of Surgery, University of Texas Medical Branch, Galveston, Texas, and MD Anderson Cancer Center Houston, Texas (V.S.K.)
| | - Ekaterina I Galanzha
- Department of Pharmacology and Toxicology, College of Medicine (A.J.S., T.W.F., S.W.R., N.J.R.) and Department of Biochemistry and Molecular Biology, College of Medicine (J.C.M.), Arkansas Nanomedicine Center, College of Medicine (M.S., V.P.Z.), Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), and Laboratory of Lymphatic Research, Diagnosis and Therapy (E.I.G.), University of Arkansas for Medical Sciences, Little Rock, Arkansas; Division of Surgical Oncology, Department of Surgery, University of Texas Medical Branch, Galveston, Texas, and MD Anderson Cancer Center Houston, Texas (V.S.K.)
| | - Sung W Rhee
- Department of Pharmacology and Toxicology, College of Medicine (A.J.S., T.W.F., S.W.R., N.J.R.) and Department of Biochemistry and Molecular Biology, College of Medicine (J.C.M.), Arkansas Nanomedicine Center, College of Medicine (M.S., V.P.Z.), Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), and Laboratory of Lymphatic Research, Diagnosis and Therapy (E.I.G.), University of Arkansas for Medical Sciences, Little Rock, Arkansas; Division of Surgical Oncology, Department of Surgery, University of Texas Medical Branch, Galveston, Texas, and MD Anderson Cancer Center Houston, Texas (V.S.K.)
| | - Vladimir P Zharov
- Department of Pharmacology and Toxicology, College of Medicine (A.J.S., T.W.F., S.W.R., N.J.R.) and Department of Biochemistry and Molecular Biology, College of Medicine (J.C.M.), Arkansas Nanomedicine Center, College of Medicine (M.S., V.P.Z.), Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), and Laboratory of Lymphatic Research, Diagnosis and Therapy (E.I.G.), University of Arkansas for Medical Sciences, Little Rock, Arkansas; Division of Surgical Oncology, Department of Surgery, University of Texas Medical Branch, Galveston, Texas, and MD Anderson Cancer Center Houston, Texas (V.S.K.)
| | - V Suzanne Klimberg
- Department of Pharmacology and Toxicology, College of Medicine (A.J.S., T.W.F., S.W.R., N.J.R.) and Department of Biochemistry and Molecular Biology, College of Medicine (J.C.M.), Arkansas Nanomedicine Center, College of Medicine (M.S., V.P.Z.), Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), and Laboratory of Lymphatic Research, Diagnosis and Therapy (E.I.G.), University of Arkansas for Medical Sciences, Little Rock, Arkansas; Division of Surgical Oncology, Department of Surgery, University of Texas Medical Branch, Galveston, Texas, and MD Anderson Cancer Center Houston, Texas (V.S.K.)
| | - Nancy J Rusch
- Department of Pharmacology and Toxicology, College of Medicine (A.J.S., T.W.F., S.W.R., N.J.R.) and Department of Biochemistry and Molecular Biology, College of Medicine (J.C.M.), Arkansas Nanomedicine Center, College of Medicine (M.S., V.P.Z.), Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), and Laboratory of Lymphatic Research, Diagnosis and Therapy (E.I.G.), University of Arkansas for Medical Sciences, Little Rock, Arkansas; Division of Surgical Oncology, Department of Surgery, University of Texas Medical Branch, Galveston, Texas, and MD Anderson Cancer Center Houston, Texas (V.S.K.)
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Jo M, Trujillo AN, Yang Y, Breslin JW. Evidence of functional ryanodine receptors in rat mesenteric collecting lymphatic vessels. Am J Physiol Heart Circ Physiol 2019; 317:H561-H574. [PMID: 31274355 DOI: 10.1152/ajpheart.00564.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In the current study, the potential contributions of ryanodine receptors (RyRs) to intrinsic pumping and responsiveness to substance P (SP) were investigated in isolated rat mesenteric collecting lymphatic vessels. Responses to SP were characterized in lymphatic vessels in the absence or presence of pretreatment with nifedipine to block L-type Ca2+ channels, caffeine to block normal release and uptake of Ca2+ from the sarcoplasmic reticulum, ryanodine to block all RyR isoforms, or dantrolene to more selectively block RyR1 and RyR3. RyR expression and localization in lymphatics was also assessed by quantitative PCR and immunofluorescence confocal microscopy. The results show that SP normally elicits a significant increase in contraction frequency and a decrease in end-diastolic diameter. In the presence of nifedipine, phasic contractions stop, yet subsequent SP treatment still elicits a strong tonic contraction. Caffeine treatment gradually relaxes lymphatics, causing a loss of phasic contractions, and prevents subsequent SP-induced tonic contraction. Ryanodine also gradually diminishes phasic contractions but without causing vessel relaxation and significantly inhibits the SP-induced tonic contraction. Dantrolene treatment did not significantly impair lymphatic contractions nor the response to SP. The mRNA for all RyR isoforms is detectable in isolated lymphatics. RyR2 and RyR3 proteins are found predominantly in the collecting lymphatic smooth muscle layer. Collectively, the data suggest that SP-induced tonic contraction requires both extracellular Ca2+ plus Ca2+ release from internal stores and that RyRs play a role in the normal contractions and responsiveness to SP of rat mesenteric collecting lymphatics.NEW & NOTEWORTHY The mechanisms that govern contractions of lymphatic vessels remain unclear. Tonic contraction of lymphatic vessels caused by substance P was blocked by caffeine, which prevents normal uptake and release of Ca2+ from internal stores, but not nifedipine, which blocks L-type channel-mediated Ca2+ entry. Ryanodine, which also disrupts normal sarcoplasmic reticulum Ca2+ release and reuptake, significantly inhibited substance P-induced tonic contraction. Ryanodine receptors 2 and 3 were detected within the smooth muscle layer of collecting lymphatic vessels.
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Affiliation(s)
- Michiko Jo
- Department of Kampo Diagnostics, Institute of Natural Medicine, University of Toyama, Toyama, Japan.,Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Andrea N Trujillo
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Ying Yang
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Jerome W Breslin
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
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11
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Yan FR, Zhu ZL, Mu YP, Zhuang XL, Lin DC, Wu ZJ, Gui LX, Lin MJ. Increased caveolin-1 expression enhances the receptor-operated Ca 2+ entry in the aorta of two-kidney, one-clip hypertensive rats. Exp Physiol 2019; 104:932-945. [PMID: 30840346 DOI: 10.1113/ep086924] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 02/25/2019] [Indexed: 12/12/2022]
Abstract
NEW FINDINGS What is the central question of this study? The aim was to examine and compare the contributions of caveolin-1 to the contractile responses mediated by L-type voltage-dependent calcium channels, store-operated Ca2+ channels and receptor-operated Ca2+ channels in two different types of arteries from two-kidney, one-clip hypertensive rats. What is the main finding and its importance? We demonstrated that the density of caveolae and caveolin-1 expression were significantly upregulated in the aorta of two-kidney, one-clip hypertensive rats, but not in the third-order branches of mesenteric arteries. We highlight that caveolin-1 plays an important role in aortic constriction by enhancing receptor-operated Ca2+ entry in the hypertensive rat model. ABSTRACT Calcium and its multiple regulatory mechanisms are crucial for the development of hypertension. Among these regulatory mechanisms, store-operated Ca2+ entry (SOCE) and receptor-operated Ca2+ entry (ROCE) mediate agonist-induced calcium influx, contributing to vascular contraction. The SOCE and ROCE are regulated by a variety of mechanisms involving caveolin-1 (Cav1), which has been found to be strongly associated with hypertension in gene polymorphism. In the present study, we investigated the role of Cav1 during the enhanced activity of calcium channels in hypertensive arteries. We demonstrated that the expression level of Cav1 was significantly increased in the aorta of two-kidney, one-clip (2K1C) hypertensive rats. The disruption of caveolae by methyl-β-cyclodextrin did not cause a marked difference in agonist-induced vasoconstriction in the third-order branches of the mesenteric arteries but strongly suppressed the aortic contractile response to endothelin-1 in the 2K1C group, which was not found in the control group. The increase in Cav1 by introduction of Cav1 scaffolding domain enhancing peptide promoted the 1-oleoyl-2-acetyl-glycerol-induced ROCE in hypertensive aortic smooth muscle cells but did not enhance the cyclopiazonic acid-induced SOCE. In the resistance arteries, similar changes were not observed, and no statistical changes of Cav1 expression were evident in the third-order branches of the mesenteric arteries. Our results indicate that increased Cav1 expression might promote the altered [Ca2+ ]i -induced aortic vasoreactivity by enhancing ROCE and be involved in the pathogenesis of hypertension.
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Affiliation(s)
- Fu-Rong Yan
- Key Laboratory of Fujian Province Universities on Ion Channel and Signal Transduction in Cardiovascular Diseases; Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, PR China.,Center for Molecular Diagnosis and Therapy, Respiratory Medicine Center of Fujian Province, Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, PR China
| | - Zhuang-Li Zhu
- Key Laboratory of Fujian Province Universities on Ion Channel and Signal Transduction in Cardiovascular Diseases; Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, PR China
| | - Yun-Ping Mu
- Key Laboratory of Fujian Province Universities on Ion Channel and Signal Transduction in Cardiovascular Diseases; Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, PR China.,Institute of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, Guangdong, PR China
| | - Xiao-Ling Zhuang
- Key Laboratory of Fujian Province Universities on Ion Channel and Signal Transduction in Cardiovascular Diseases; Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, PR China
| | - Da-Cen Lin
- Key Laboratory of Fujian Province Universities on Ion Channel and Signal Transduction in Cardiovascular Diseases; Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, PR China
| | - Zhi-Juan Wu
- Key Laboratory of Fujian Province Universities on Ion Channel and Signal Transduction in Cardiovascular Diseases; Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, PR China
| | - Long-Xin Gui
- Key Laboratory of Fujian Province Universities on Ion Channel and Signal Transduction in Cardiovascular Diseases; Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, PR China
| | - Mo-Jun Lin
- Key Laboratory of Fujian Province Universities on Ion Channel and Signal Transduction in Cardiovascular Diseases; Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, PR China
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12
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McDonnell F, Dismuke WM, Overby DR, Stamer WD. Pharmacological regulation of outflow resistance distal to Schlemm's canal. Am J Physiol Cell Physiol 2018; 315:C44-C51. [PMID: 29631366 DOI: 10.1152/ajpcell.00024.2018] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The trabecular meshwork (TM) and Schlemm's canal generate the majority of outflow resistance; however, the distal regions of the conventional outflow pathway account for 25-50% of total resistance. Sections of distal vessels are surrounded by α-smooth muscle actin-containing cells, indicating that they may be vasoregulated. This study examined the effect of a potent vasodilator, nitric oxide (NO), and its physiological antagonist, endothelin-1 (ET-1), on the regulation of outflow resistance in the distal regions of the conventional outflow pathway. Using a physiological model of the conventional outflow pathway, human and porcine anterior segments were perfused in organ culture under constant flow conditions, while intrachamber pressure was continually monitored. For porcine anterior segments, a stable baseline outflow facility with TM intact was first achieved before anterior segments were removed and a trabeculotomy was performed. For human anterior segments, a trabeculotomy was immediately performed. In human anterior segments, 100 nM ET-1 significantly decreased distal outflow facility from 0.49 ± 0.26 to 0.31 ± 0.18 (mean ± SD) µl·min-1·mmHg, P < 0.01. Perfusion with 100 µM diethylenetriamine-NO in the presence of 1 nM ET-1 immediately reversed ET-1 effects, significantly increasing distal outflow facility to 0.54 ± 0.35 µl·min-1·mmHg, P = 0.01. Similar results were obtained in porcine anterior segment experiments. Therefore, data show a dynamic range of resistance generation by distal vessels in both the human and the porcine conventional outflow pathways. Interestingly, maximal contraction of vessels in the distal outflow tract of trabeculotomized eyes generated resistance very near physiological levels for both species having an intact TM.
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Affiliation(s)
- Fiona McDonnell
- Department of Ophthalmology, Duke University , Durham, North Carolina
| | - W Michael Dismuke
- Department of Ophthalmology, Duke University , Durham, North Carolina
| | - Darryl R Overby
- Department of Bioengineering, Imperial College London , London , United Kingdom
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University , Durham, North Carolina.,Department of Biomedical Engineering, Duke University , Durham, North Carolina
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13
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Jiao HX, Mu YP, Gui LX, Yan FR, Lin DC, Sham JS, Lin MJ. Increase in caveolae and caveolin-1 expression modulates agonist-induced contraction and store- and receptor-operated Ca2+ entry in pulmonary arteries of pulmonary hypertensive rats. Vascul Pharmacol 2016; 84:55-66. [DOI: 10.1016/j.vph.2016.06.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 05/03/2016] [Accepted: 06/11/2016] [Indexed: 10/21/2022]
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Endothelin-1: Biosynthesis, Signaling and Vasoreactivity. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 77:143-75. [PMID: 27451097 DOI: 10.1016/bs.apha.2016.05.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Endothelin-1 (ET-1) is an extremely potent vasoconstrictor peptide originally isolated from endothelial cells. Its synthesis, mainly regulated at the gene transcription level, involves processing of a precursor by a furin-type proprotein convertase to an inactive intermediate, big ET-1. The latter peptide can then be cleaved directly by an endothelin-converting enzyme (ECE) into ET-1 or reach the active metabolite through a two-step process involving chymase hydrolyzing big ET-1 to ET-1 (1-31), itself needing conversion to ET-1 by neprilysin (NEP) to exert physiological activity. ET-1 signals through two G protein-coupled receptors, endothelin receptor A (ETA) and endothelin receptor B (ETB). Both receptors induce an increase in intracellular Ca(2+), mainly from the extracellular space through voltage-independent mechanisms, the receptor-operated channels and store-operated channels. ET-1 also induces signaling through epidermal growth factor receptor transactivation, oxidative stress induction, rho-kinase, and the activation (ETA) or inhibition (ETB) of the adenylate cyclase/cyclic adenosine monophosphate pathway. Arterial vasoconstriction is mediated mainly by the ETA receptor. ET-1, via endothelium-located ETB, relaxes arteries or constricts vessels following activation of the same receptor type on the smooth muscle, where it can interact with ETA. In addition, ETB-dependent vasoconstriction seems more prominent in the venous vasculature. A better understanding of how ET-1 is synthesized and how ETA and ETB receptors interact could help design better pharmacological agents in the treatment of cardiovascular diseases where targeting the ET-1 system is indicated.
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15
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Padera TP, Meijer EFJ, Munn LL. The Lymphatic System in Disease Processes and Cancer Progression. Annu Rev Biomed Eng 2016; 18:125-58. [PMID: 26863922 DOI: 10.1146/annurev-bioeng-112315-031200] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Advances in our understanding of the structure and function of the lymphatic system have made it possible to identify its role in a variety of disease processes. Because it is involved not only in fluid homeostasis but also in immune cell trafficking, the lymphatic system can mediate and ultimately alter immune responses. Our rapidly increasing knowledge of the molecular control of the lymphatic system will inevitably lead to new and effective therapies for patients with lymphatic dysfunction. In this review, we discuss the molecular and physiological control of lymphatic vessel function and explore how the lymphatic system contributes to many disease processes, including cancer and lymphedema.
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Affiliation(s)
- Timothy P Padera
- Edwin L. Steele Laboratories, Department of Radiation Oncology, and Cancer Center, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114;
| | - Eelco F J Meijer
- Edwin L. Steele Laboratories, Department of Radiation Oncology, and Cancer Center, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114;
| | - Lance L Munn
- Edwin L. Steele Laboratories, Department of Radiation Oncology, and Cancer Center, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114;
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16
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Abstract
The ability of cells to sense and respond to physical forces has been recognized for decades, but researchers are only beginning to appreciate the fundamental importance of mechanical signals in biology. At the larger scale, there has been increased interest in the collective organization of cells and their ability to produce complex, "emergent" behaviors. Often, these complex behaviors result in tissue-level control mechanisms that manifest as biological oscillators, such as observed in fireflies, heartbeats, and circadian rhythms. In many cases, these complex, collective behaviors are controlled--at least in part--by physical forces imposed on the tissue or created by the cells. Here, we use mathematical simulations to show that two complementary mechanobiological oscillators are sufficient to control fluid transport in the lymphatic system: Ca(2+)-mediated contractions can be triggered by vessel stretch, whereas nitric oxide produced in response to the resulting fluid shear stress causes the lymphatic vessel to relax locally. Our model predicts that the Ca(2+) and NO levels alternate spatiotemporally, establishing complementary feedback loops, and that the resulting phasic contractions drive lymph flow. We show that this mechanism is self-regulating and robust over a range of fluid pressure environments, allowing the lymphatic vessels to provide pumping when needed but remain open when flow can be driven by tissue pressure or gravity. Our simulations accurately reproduce the responses to pressure challenges and signaling pathway manipulations observed experimentally, providing an integrated conceptual framework for lymphatic function.
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17
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Souza-Smith FM, Kerut EK, Breslin JW, Molina PE. Mechanisms of Acute Alcohol Intoxication-Induced Modulation of Cyclic Mobilization of [Ca²⁺] in Rat Mesenteric Lymphatic Vessels. Lymphat Res Biol 2015; 13:93-9. [PMID: 26056854 DOI: 10.1089/lrb.2014.0048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND We have demonstrated that acute alcohol intoxication (AAI) increases the magnitude of Ca(2+) transients in pumping lymphatic vessels. We tested the contribution of extracellular Ca(2+) via L-type Ca(2+) channels and intracellular Ca(2+) release from the sarcoplasmic reticulum (SR) to the AAI-induced increase in Ca(2+) transients. METHODS AND RESULTS AAI was produced by intragastric administration of 30% alcohol to conscious, unrestrained rats; isovolumic administration of water served as the control. Mesenteric lymphatic vessels were isolated, cannulated, and loaded with Fura-2 AM to measure changes in intracellular Ca(2+). Measurements were made at intraluminal pressures of 2, 6, and 10 cm H2O. L-type Ca(2+) channels were blocked with nifedipine; IP-3 receptors were inhibited with xestospongin C; and SR Ca(2+) release and Ca(2+) pool (Ca(2+) free APSS) were achieved using caffeine. Nifedipine reduced lymphatic Ca(2+) transient magnitude in both AAI and control groups at all pressures tested, but reduced lymphatic contraction frequency only in the control group. Xestospongin C did not significantly change any of the Ca(2+) parameters in either group; however, fractional shortening increased in the controls at low transmural pressure. RyR (ryanodine receptor) activation with caffeine resulted in a single contraction with a greater Ca(2+) transient in lymphatics from AAI than those from controls. SR Ca(2+) pool was also greater in lymphatics isolated from AAI- than from control animals. CONCLUSIONS These data suggest that 1) L-type Ca(2+) channels contribute to the AAI-induced increase in lymphatic Ca(2+) transient, 2) blockage of IP-3 receptors could increase calcium sensitivity, and 3) AAI increases Ca(2+) storage in the SR in lymphatic vessels.
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Affiliation(s)
- Flavia M Souza-Smith
- 1 Department of Physiology, Alcohol and Drug Abuse Center of Excellence, Louisiana State University Health Sciences Center (LSUHSC) , New Orleans, Louisiana
| | | | - Jerome W Breslin
- 3 Department of Molecular Pharmacology and Physiology, University of South Florida , Tampa, Florida
| | - Patricia E Molina
- 1 Department of Physiology, Alcohol and Drug Abuse Center of Excellence, Louisiana State University Health Sciences Center (LSUHSC) , New Orleans, Louisiana
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18
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Munn LL. Mechanobiology of lymphatic contractions. Semin Cell Dev Biol 2015; 38:67-74. [PMID: 25636584 DOI: 10.1016/j.semcdb.2015.01.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 01/30/2023]
Abstract
The lymphatic system is responsible for controlling tissue fluid pressure by facilitating flow of lymph (i.e. the plasma and cells that enter the lymphatic system). Because lymph contains cells of the immune system, its transport is not only important for fluid homeostasis, but also immune function. Lymph drainage can occur via passive flow or active pumping, and much research has identified the key biochemical and mechanical factors that affect output. Although many studies and reviews have addressed how tissue properties and fluid mechanics (i.e. pressure gradients) affect lymph transport [1-3] there is less known about lymphatic mechanobiology. As opposed to passive mechanical properties, mechanobiology describes the active coupling of mechanical signals and biochemical pathways. Lymphatic vasomotion is the result of a fascinating system affected by mechanical forces exerted by the flowing lymph, including pressure-induced vessel stretch and flow-induced shear stresses. These forces can trigger or modulate biochemical pathways important for controlling the lymphatic contractions. Here, I review the current understanding of lymphatic vessel function, focusing on vessel mechanobiology, and summarize the prospects for a comprehensive understanding that integrates the mechanical and biomechanical control mechanisms in the lymphatic system.
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Affiliation(s)
- Lance L Munn
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, United States.
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19
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Chakraborty S, Davis MJ, Muthuchamy M. Emerging trends in the pathophysiology of lymphatic contractile function. Semin Cell Dev Biol 2015; 38:55-66. [PMID: 25617600 DOI: 10.1016/j.semcdb.2015.01.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 01/12/2015] [Accepted: 01/13/2015] [Indexed: 01/19/2023]
Abstract
Lymphatic contractile dysfunction is central to a number of pathologies that affect millions of people worldwide. Due to its critical role in the process of inflammation, a dysfunctional lymphatic system also compromises the immune response, further exacerbating a number of inflammation related diseases. Despite the critical physiological functions accomplished by the transport of lymph, a complete understanding of the contractile machinery of the lymphatic system lags far behind that of the blood vasculature. However, there has been a surge of recent research focusing on different mechanisms that underlie both physiological and pathophysiological aspects of lymphatic contractile function. This review summarizes those emerging paradigms that shed some novel insights into the contractile physiology of the lymphatics in normal as well as different disease states. In addition, this review emphasizes the recent progress made in our understanding of various contractile parameters and regulatory elements that contribute to the normal functioning of the lymphatics.
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Affiliation(s)
- Sanjukta Chakraborty
- Department of Medical Physiology, Cardiovascular Research Institute Division of Lymphatic Biology, Texas A&M Health Science Center College of Medicine, United States
| | - Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, United States.
| | - Mariappan Muthuchamy
- Department of Medical Physiology, Cardiovascular Research Institute Division of Lymphatic Biology, Texas A&M Health Science Center College of Medicine, United States.
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Dougherty PJ, Nepiyushchikh ZV, Chakraborty S, Wang W, Davis MJ, Zawieja DC, Muthuchamy M. PKC activation increases Ca²⁺ sensitivity of permeabilized lymphatic muscle via myosin light chain 20 phosphorylation-dependent and -independent mechanisms. Am J Physiol Heart Circ Physiol 2014; 306:H674-83. [PMID: 24414065 DOI: 10.1152/ajpheart.00732.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The contractile activity of muscle cells lining the walls of collecting lymphatics is responsible for generating and regulating flow within the lymphatic system. Activation of PKC signaling contributes to the regulation of smooth muscle contraction by enhancing sensitivity of the contractile apparatus to Ca(2+). It is currently unknown whether PKC signaling contributes to the regulation of lymphatic muscle contraction. We hypothesized that the activation of PKC signaling would increase the sensitivity of the lymphatic myofilament to Ca(2+). To test this hypothesis, we determined the effects of PKC activation with phorbol esters [PMA or phorbol dibutyrate (PDBu)] on the contractile behavior of α-toxin-permeabilized rat mesenteric and cervical lymphatics or the thoracic duct. The addition of PMA or PDBu induced a significant increase in the contractile force of submaximally activated α-toxin-permeabilized lymphatic muscle independent of a change in intracellular Ca(2+) concentration, and the Ca(2+)-force relationship of lymphatic muscle was significantly left shifted, indicating greater myofilament Ca(2+) sensitivity. Phorbol esters increased the maximal rate of force development, whereas the rate of relaxation was reduced. Western blot and immunohistochemistry data indicated that the initial rapid increase in tension development after stimulation by PDBu was associated with myosin light chain (MLC)20 phosphorylation; however, the later, steady-state Ca(2+) sensitization of permeabilized lymphatic muscle was not associated with increased phosphorylation of MLC20 at Ser(19), 17-kDa C-kinase-potentiated protein phosphatase-1 inhibitor at Thr(38), or caldesmon at Ser(789). Thus, these data indicate that PKC-dependent Ca(2+) sensitization of lymphatic muscle may involve MLC20 phosphorylation-dependent and -independent mechanism(s).
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Affiliation(s)
- Patrick J Dougherty
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, College Station, Texas; and
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Karlsen TV, McCormack E, Mujic M, Tenstad O, Wiig H. Minimally invasive quantification of lymph flow in mice and rats by imaging depot clearance of near-infrared albumin. Am J Physiol Heart Circ Physiol 2011; 302:H391-401. [PMID: 22101523 DOI: 10.1152/ajpheart.00842.2011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There is a lack of available methods to noninvasively quantify lymphatic function in small experimental animals, a necessity for studies on lymphatic system pathophysiology. We present a new method to quantify lymph flow in mice and rats, based on optically monitoring the depot clearance of near-infrared fluorescently labeled albumin and subsequent calculation of removal rate constants (k). BSA was conjugated with Alexa680 NHS ester and remained stable in protein-rich solutions without free dye dissociation. To assess lymph flow, mice or rats were imaged every 30 or 60 min during a 3- to 6-h period following an intradermal injection of 0.5 or 1 μl Alexa680-albumin. Mice were awake between measurements, whereas rats were anesthetized throughout the experiment. The k, a parameter defined as equivalent to lymph flow, was calculated from the slopes of the resultant log-linear washout curves and averaged -0.40 ± 0.03 and -0.30 ± 0.02%/min for control C57BL/6 and C3H mice, respectively. Local administration of the vasoconstrictor endothelin-1 in mice led to a significant reduction in k, whereas overhydration in rats increased k, reflecting the coupling between capillary filtration and lymph flow. Furthermore, k was 50% of wild type in lymphedema Chy mice where dermal lymphatics are absent. We conclude that lymph flow can be determined as its rate constant k by optical imaging of depot clearance of submicroliter amounts of Alexa680-albumin. The method offers a minimally invasive, reproducible, and simple alternative to assess lymphatic function in mice and rats.
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Affiliation(s)
- Tine V Karlsen
- Department of Biomedicine, Hematology Section, University of Bergen, Jonas Lies Vei 91, Bergen, Norway.
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23
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Myslobodsky M, Eldan A. Winning a won game: caffeine panacea for obesity syndemic. Curr Neuropharmacol 2010; 8:149-60. [PMID: 21119886 PMCID: PMC2923369 DOI: 10.2174/157015910791233213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 02/20/2010] [Accepted: 02/23/2010] [Indexed: 02/08/2023] Open
Abstract
Over the past decades, chronic sleep reduction and a concurrent development of obesity have been recognized as a common problem in the industrialized world. Among its numerous untoward effects, there is a possibility that insomnia is also a major contributor to obesity. This attribution poses a problem for caffeine, an inexpensive, “natural” agent that is purported to improve a number of conditions and is often indicated in a long-term pharmacotherapy in the context of weight management. The present study used the “common target” approach by exploring the tentative shared molecular networks of insomnia and adiposity. It discusses caffeine targets beyond those associated with adenosine signaling machinery, phosphodiesterases, and calcium release channels. Here, we provide a view suggesting that caffeine could exert some of its effects by acting on several signaling complexes composed of HIF-1α/VEGF/IL-8 along with NO, TNF-α, IL1, and GHRH, among others. Although the relevance of these targets to the reported therapeutic effects of caffeine has remained difficult to assess, the utilization of caffeine efficacies and potencies recommend its repurposing for development of novel therapeutic approaches. Among indications mentioned, are neuroprotective, nootropic, antioxidant, proliferative, anti-fibrotic, and anti-angiogenic that appear under a variety of dissimilar diagnostic labels comorbid with obesity. In the absence of safe and efficacious antiobesity agents, caffeine remains an attractive adjuvant.
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von der Weid PY, Rahman M, Imtiaz MS, van Helden DF. Spontaneous transient depolarizations in lymphatic vessels of the guinea pig mesentery: pharmacology and implication for spontaneous contractility. Am J Physiol Heart Circ Physiol 2008; 295:H1989-2000. [PMID: 18790842 DOI: 10.1152/ajpheart.00007.2008] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Guinea pig mesenteric lymphatic vessels exhibit rhythmic constrictions induced by action potential (AP)-like spikes and initiated by entrainment of spontaneous transient depolarizations (STDs). To characterize STDs and the signaling mechanisms responsible for their occurrence, we used intracellular microelectrodes, Ca2+ imaging, and pharmacological agents. In our investigation of the role of intracellular Ca2+ released from Ca2+ stores, we observed that intracellular Ca2+ transients accompanied some STDs, although there were many exceptions where Ca2+ transients occurred without accompanying STDs. STD frequency and amplitude were markedly affected by activators/inhibitors of inositol 1,4,5-trisphosphate receptors (IP3Rs) but not by treatments known to alter Ca2+ release via ryanodine receptors. A role for Ca2+-activated Cl(-) (Cl(Ca)) channels was indicated, as STDs were dependent on the Cl(-) but not Na+ concentration of the superfusing solution and were inhibited by the Cl(Ca) channel blockers niflumic acid (NFA), anthracene 9-carboxylic acid, and 5-nitro-2-(3-phenylpropylamino)benzoic acid but not by the volume-regulated Cl(-) blocker DIDS. Increases in STD frequency and amplitude induced by agonist stimulation were also inhibited by NFA. Nifedipine, the hyperpolarization-activated inward current blocker ZD-7288, and the nonselective cation/store-operated channel blockers SKF-96365, Gd3+, and Ni2+ had no or marginal effects on STD activity. However, nifedipine, 2-aminoethoxydiphenyl borate, NFA, SKF-96365, Gd3+, and Ni2+ altered the occurrence of spontaneous APs. Our findings support a role for Ca2+ release through IP3Rs and a resultant opening of Cl(Ca) channels in STD generation and confirm the importance of these events in the initiation of lymphatic spontaneous APs and subsequent contractions. The abolition of spontaneous APs by blockers of other excitatory ion channels suggests a contribution of these conductances to lymphatic pacemaking.
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Affiliation(s)
- Pierre-Yves von der Weid
- Inflammation Research Network, Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB, Canada T2N 4N1.
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Muthuchamy M, Zawieja D. Molecular regulation of lymphatic contractility. Ann N Y Acad Sci 2008; 1131:89-99. [PMID: 18519962 DOI: 10.1196/annals.1413.008] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The lymphatic system plays critical roles in body fluid and macromolecular homeostasis, lipid absorption, immune function, and metastasis. To accomplish these tasks, the lymphatics must move lymph and its contents from the interstitial space through the lymph vessels and nodes and into the great veins. Contrary to popular belief, lymph does not passively "drain" down this pathway, because the net pressure gradients oppose flow. Instead, the lymphatics must act as both the conduits that direct and regulate lymph flow and the pumps that generate the lymph flow. Thus, to regulate lymph transport and function, both lymphatic pumping and flow resistance must be controlled. Both of these processes occur via regulation of lymphatic muscle contractions, which are classically thought to occur via the interaction of cell calcium with regulatory and contractile proteins. However, our knowledge of this regulation of lymphatic contractile function is far from complete. In this chapter we review our understanding of the important molecular mechanisms, the calcium regulation, and the contractile/regulatory proteins that control lymphatic contractions. A better understanding of these mechanisms could provide the basis for the development of better diagnostic and treatment modalities for lymphatic dysfunction. While progress has been made in our understanding of the molecular biology of lymphangiogenesis as a result of the development of potential lymphangiogenic therapeutic targets, there are currently no therapeutic agents that specifically modulate lymphatic pump function and lymph flow via lymphatic muscle. However, their development will not be possible until the molecular basis of lymphatic contractility is more fully understood.
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Affiliation(s)
- Mariappan Muthuchamy
- Department of Systems Biology and Translational Medicine, College of Medicine, Cardiovascular Research Institute Division of Lymphatic Biology, Texas A&M Health Science Center, College Station, TX 77843-1114, USA
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Dougherty PJ, Davis MJ, Zawieja DC, Muthuchamy M. Calcium sensitivity and cooperativity of permeabilized rat mesenteric lymphatics. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1524-32. [PMID: 18305021 DOI: 10.1152/ajpregu.00888.2007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Lymphatic muscle contraction is critical for the centripetal movement of lymph that regulates fluid balance, protein homeostasis, lipid absorption, and immune function. We have demonstrated that lymphatic muscle has both smooth and striated muscle contractile elements; however, the basic contractile properties of this tissue remain poorly defined. We hypothesized that contractile characteristics of lymphatic myofilaments would be different from vascular smooth muscle myofilaments. To test this hypothesis, -log[Ca(2+)] (pCa)-tension relationship was determined for alpha-toxin permeabilized mesenteric lymphatics, arteries, and veins. The Ca(2+) sensitivity (pCa(50)) of mesenteric lymphatics was significantly lower compared with arteries (6.16 +/- 0.05 vs. 6.44 +/- 0.02; P < 0.05), whereas there was no difference in pCa(50) between lymphatics and veins (6.16 +/- 0.05 vs. 6.00 +/- 0.10; not significant). The Hill coefficient for alpha-toxin-permeabilized lymphatics was not significantly different from arteries but was significantly greater than that of the veins (1.98 +/- 0.19 vs. 1.21 +/- 0.18; P < 0.05). In addition, the maximal tension and pCa(50) values were significantly greater in alpha-toxin-permeabilized lymphatics compared with beta-escin-permeabilized lymphatics (0.27 +/- 0.03 vs. 0.15 +/- 0.01 and 6.16 +/- 0.05 vs. 5.86 +/- 0.06 mN/mm, respectively; P < 0.05), whereas the Hill coefficient was significantly greater in beta-escin-permeabilized lymphatics. Western blot analyses revealed that CPI-17 levels were significantly decreased by about 50% in beta-escin-permeabilized lymphatics, compared with controls, whereas no change in the level of calmodulin was detected. Our data constitute the first description of the pCa-tension relationship in permeabilized lymphatic muscle. It suggests that differences in myofilament Ca(2+) sensitivity and cooperativity among lymphatic muscle and vascular smooth muscles contribute to the functional differences that exist between these tissues.
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Affiliation(s)
- Patrick J Dougherty
- Department of Systems Biology and Translational Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX, USA
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Imtiaz MS, Zhao J, Hosaka K, von der Weid PY, Crowe M, van Helden DF. Pacemaking through Ca2+ stores interacting as coupled oscillators via membrane depolarization. Biophys J 2007; 92:3843-61. [PMID: 17351003 PMCID: PMC1869001 DOI: 10.1529/biophysj.106.095687] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
This study presents an investigation of pacemaker mechanisms underlying lymphatic vasomotion. We tested the hypothesis that active inositol 1,4,5-trisphosphate receptor (IP(3)R)-operated Ca(2+) stores interact as coupled oscillators to produce near-synchronous Ca(2+) release events and associated pacemaker potentials, this driving action potentials and constrictions of lymphatic smooth muscle. Application of endothelin 1 (ET-1), an agonist known to enhance synthesis of IP(3), to quiescent lymphatic smooth muscle syncytia first enhanced spontaneous Ca(2+) transients and/or intracellular Ca(2+) waves. Larger near-synchronous Ca(2+) transients then occurred leading to global synchronous Ca(2+) transients associated with action potentials and resultant vasomotion. In contrast, blockade of L-type Ca(2+) channels with nifedipine prevented ET-1 from inducing near-synchronous Ca(2+) transients and resultant action potentials, leaving only asynchronous Ca(2+) transients and local Ca(2+) waves. These data were well simulated by a model of lymphatic smooth muscle with: 1), oscillatory Ca(2+) release from IP(3)R-operated Ca(2+) stores, which causes depolarization; 2), L-type Ca(2+) channels; and 3), gap junctions between cells. Stimulation of the stores caused global pacemaker activity through coupled oscillator-based entrainment of the stores. Membrane potential changes and positive feedback by L-type Ca(2+) channels to produce more store activity were fundamental to this process providing long-range electrochemical coupling between the Ca(2+) store oscillators. We conclude that lymphatic pacemaking is mediated by coupled oscillator-based interactions between active Ca(2+) stores. These are weakly coupled by inter- and intracellular diffusion of store activators and strongly coupled by membrane potential. Ca(2+) store-based pacemaking is predicted for cellular systems where: 1), oscillatory Ca(2+) release induces depolarization; 2), membrane depolarization provides positive feedback to induce further store Ca(2+) release; and 3), cells are interconnected. These conditions are met in a surprisingly large number of cellular systems including gastrointestinal, lymphatic, urethral, and vascular tissues, and in heart pacemaker cells.
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Affiliation(s)
- Mohammad S Imtiaz
- Neuroscience Group, School of Biomedical Sciences, Faculty of Health, The University of Newcastle, Newcastle, Australia.
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Kawanabe Y, Nauli SM. Involvement of extracellular Ca2+ influx through voltage-independent Ca2+ channels in endothelin-1 function. Cell Signal 2005; 17:911-6. [PMID: 15894164 DOI: 10.1016/j.cellsig.2005.01.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Accepted: 01/07/2005] [Indexed: 11/20/2022]
Abstract
This article reviews the types and roles of voltage-independent Ca(2+) channels involved in the endothelin-1 (ET-1)-induced functional responses such as vascular contraction, cell proliferation, and intracellular Ca(2+)-dependent signaling pathways and discusses the molecular mechanisms for the activation of voltage-independent Ca(2+) channels by ET-1. ET-1 activates some types of voltage-independent Ca(2+) channels, such as Ca(2+)-permeable nonselective cation channels (NSCCs) and store-operated Ca(2+) channels (SOCC). Extracellular Ca(2+) influx through these voltage-independent Ca(2+) channels plays essential roles in ET-1-induced vascular contraction, cell proliferation, activation of epidermal growth factor receptor tyrosine kinase, regulation of proline-rich tyrosine kinase, and release of arachidonic acid. The experiments using various constructs of endothelin receptors reveal the importance of G(q) and G(12) families in activation of these Ca(2+) channels by ET-1. These findings provide a potential therapeutic mechanism of a functional interrelationship between G(q)/G(12) proteins and voltage-independent Ca(2+) channels in the pathophysiology of ET-1, such as in chronic heart failure, hypertension, and cerebral vasospasm.
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Affiliation(s)
- Yoshifumi Kawanabe
- Renal Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
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Imtiaz MS, Katnik CP, Smith DW, van Helden DF. Role of voltage-dependent modulation of store Ca2+ release in synchronization of Ca2+ oscillations. Biophys J 2005; 90:1-23. [PMID: 16040741 PMCID: PMC1367009 DOI: 10.1529/biophysj.104.058743] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Slow waves are rhythmic depolarizations that underlie mechanical activity of many smooth muscles. Slow waves result through rhythmic Ca(2+) release from intracellular Ca(2+) stores through inositol 1,4,5-trisphosphate (IP(3)) sensitive receptors and Ca(2+)-induced Ca(2+) release. Ca(2+) oscillations are transformed into membrane depolarizations by generation of a Ca(2+)-activated inward current. Importantly, the store Ca(2+) oscillations that underlie slow waves are entrained across many cells over large distances. It has been shown that IP(3) receptor-mediated Ca(2+) release is enhanced by membrane depolarization. Previous studies have implicated diffusion of Ca(2+) or the second messenger IP(3) across gap junctions in synchronization of Ca(2+) oscillations. In this study, a novel mechanism of Ca(2+) store entrainment through depolarization-induced IP(3) receptor-mediated Ca(2+) release is investigated. This mechanism is significantly different from chemical coupling-based mechanisms, as membrane potential has a coupling effect over distances several orders of magnitude greater than either diffusion of Ca(2+) or IP(3) through gap junctions. It is shown that electrical coupling acting through voltage-dependent modulation of store Ca(2+) release is able to synchronize oscillations of cells even when cells are widely separated and have different intrinsic frequencies of oscillation.
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Affiliation(s)
- Mohammad S Imtiaz
- The Neuroscience Group, School of Biomedical Sciences, Faculty of Health, The University of Newcastle, Callaghan NSW 2308, Australia.
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Rockson SG. Literature watch. Hirakawa S, Hong YK, Harvey N, Schacht V, Matsuda K, Libermann T, Detmar M. Identification of vascular lineage-specific genes by transcriptional profiling of isolated blood vascular and lymphatic endothelial cells. Am J Pathol. 2003; 162:575-86. Lymphat Res Biol 2004; 2:61-4. [PMID: 15609929 DOI: 10.1089/1539685041690427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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