1
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Harlow RC, Pea GA, Broyhill SE, Patro A, Bromert KH, Stewart RH, Heaps CL, Castorena-Gonzalez JA, Dongaonkar RM, Zawieja SD. Loss of anoctamin 1 reveals a subtle role for BK channels in lymphatic muscle action potentials. J Physiol 2024; 602:3351-3373. [PMID: 38704841 PMCID: PMC11250503 DOI: 10.1113/jp285459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 04/11/2024] [Indexed: 05/07/2024] Open
Abstract
Ca2+ signalling plays a crucial role in determining lymphatic muscle cell excitability and contractility through its interaction with the Ca2+-activated Cl- channel anoctamin 1 (ANO1). In contrast, the large-conductance (BK) Ca2+-activated K+ channel (KCa) and other KCa channels have prominent vasodilatory actions by hyperpolarizing vascular smooth muscle cells. Here, we assessed the expression and contribution of the KCa family to mouse and rat lymphatic collecting vessel contractile function. The BK channel was the only KCa channel consistently expressed in fluorescence-activated cell sorting-purified mouse lymphatic muscle cell lymphatic muscle cells. We used a pharmacological inhibitor of BK channels, iberiotoxin, and small-conductance Ca2+-activated K+ channels, apamin, to inhibit KCa channels acutely in ex vivo isobaric myography experiments and intracellular membrane potential recordings. In basal conditions, BK channel inhibition had little to no effect on either mouse inguinal-axillary lymphatic vessel (MIALV) or rat mesenteric lymphatic vessel contractions or action potentials (APs). We also tested BK channel inhibition under loss of ANO1 either by genetic ablation (Myh11CreERT2-Ano1 fl/fl, Ano1ismKO) or by pharmacological inhibition with Ani9. In both Ano1ismKO MIALVs and Ani9-pretreated MIALVs, inhibition of BK channels increased contraction amplitude, increased peak AP and broadened the peak of the AP spike. In rat mesenteric lymphatic vessels, BK channel inhibition also abolished the characteristic post-spike notch, which was exaggerated with ANO1 inhibition, and significantly increased the peak potential and broadened the AP spike. We conclude that BK channels are present and functional on mouse and rat lymphatic muscle cells but are otherwise masked by the dominance of ANO1. KEY POINTS: Mouse and rat lymphatic muscle cells express functional BK channels. BK channels make little contribution to either rat or mouse lymphatic collecting vessel contractile function in basal conditions across a physiological pressure range. ANO1 limits the peak membrane potential achieved in the action potential and sets a plateau potential limiting the voltage-dependent activation of BK. BK channels are activated when ANO1 is absent or blocked and slightly impair contractile strength by reducing the peak membrane potential achieved in the action potential spike and accelerating the post-spike repolarization.
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Affiliation(s)
- Rebecca C Harlow
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX, USA
| | - Grace A Pea
- Department of Medical Pharmacology & Physiology, University of Missouri, Columbia, MO, USA
| | - Sarah E Broyhill
- Department of Medical Pharmacology & Physiology, University of Missouri, Columbia, MO, USA
| | - Advaya Patro
- Department of Medical Pharmacology & Physiology, University of Missouri, Columbia, MO, USA
| | - Karen H Bromert
- Department of Medical Pharmacology & Physiology, University of Missouri, Columbia, MO, USA
| | - Randolph H Stewart
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX, USA
| | - Cristine L Heaps
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX, USA
| | | | - Ranjeet M Dongaonkar
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX, USA
| | - Scott D Zawieja
- Department of Medical Pharmacology & Physiology, University of Missouri, Columbia, MO, USA
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2
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Hancock EJ, Zawieja SD, Macaskill C, Davis MJ, Bertram CD. A dual-clock-driven model of lymphatic muscle cell pacemaking to emulate knock-out of Ano1 or IP3R. J Gen Physiol 2023; 155:e202313355. [PMID: 37851028 PMCID: PMC10585120 DOI: 10.1085/jgp.202313355] [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: 01/29/2023] [Revised: 08/14/2023] [Accepted: 09/25/2023] [Indexed: 10/19/2023] Open
Abstract
Lymphatic system defects are involved in a wide range of diseases, including obesity, cardiovascular disease, and neurological disorders, such as Alzheimer's disease. Fluid return through the lymphatic vascular system is primarily provided by contractions of muscle cells in the walls of lymphatic vessels, which are in turn driven by electrochemical oscillations that cause rhythmic action potentials and associated surges in intracellular calcium ion concentration. There is an incomplete understanding of the mechanisms involved in these repeated events, restricting the development of pharmacological treatments for dysfunction. Previously, we proposed a model where autonomous oscillations in the membrane potential (M-clock) drove passive oscillations in the calcium concentration (C-clock). In this paper, to model more accurately what is known about the underlying physiology, we extend this model to the case where the M-clock and the C-clock oscillators are both active but coupled together, thus both driving the action potentials. This extension results from modifications to the model's description of the IP3 receptor, a key C-clock mechanism. The synchronised dual-driving clock behaviour enables the model to match IP3 receptor knock-out data, thus resolving an issue with previous models. We also use phase-plane analysis to explain the mechanisms of coupling of the dual clocks. The model has the potential to help determine mechanisms and find targets for pharmacological treatment of some causes of lymphoedema.
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Affiliation(s)
- Edward J. Hancock
- School of Mathematics and Statistics, University of Sydney, Sydney, Australia
| | - Scott D. Zawieja
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Charlie Macaskill
- 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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3
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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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4
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Sedaghati F, Dixon JB, Gleason RL. A 1D model characterizing the role of spatiotemporal contraction distributions on lymph transport. Sci Rep 2023; 13:21241. [PMID: 38040740 PMCID: PMC10692214 DOI: 10.1038/s41598-023-48131-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 11/22/2023] [Indexed: 12/03/2023] Open
Abstract
Lymphedema is a condition in which lymph transport is compromised. The factors that govern the timing of lymphatic contractions are largely unknown; however, these factors likely play a central role in lymphatic health. Computational models have proven useful in quantifying changes in lymph transport; nevertheless, there is still much unknown regarding the regulation of contractions. The purpose of this paper is to utilize computational modeling to examine the role of pacemaking activity in lymph transport. A 1D fluid-solid modeling framework was utilized to describe the interaction between the contracting vessel and the lymph flow. The distribution of contractions along a three-lymphangion chain in time and space was determined by specifying the pacemaking sites and parameters obtained from experimentation. The model effectively replicates the contractility patterns in experiments. Quantitatively, the flow rates were measured at 5.44 and 2.29 [Formula: see text], and the EF values were 78% and less than 33% in the WT and KO models, respectively, which are consistent with the literature. Applying pacemaking parameters in this modeling framework effectively captures lymphatic contractile wave propagations and their relation to lymph transport. It can serve as a motivation for conducting novel studies to evaluate lymphatic pumping function during the development of lymphedema.
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Affiliation(s)
- Farbod Sedaghati
- The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - J Brandon Dixon
- The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
- The Wallace H. Coulter Georgia Tech/Emory Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Rudolph L Gleason
- The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
- The Wallace H. Coulter Georgia Tech/Emory Department of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle, Room 216F, Atlanta, GA, 30313, USA.
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5
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Lei PJ, Ruscic KJ, Roh K, Rajotte JJ, O'Melia MJ, Bouta EM, Marquez M, Pereira ER, Kumar AS, Arroyo-Ataz G, Razavi MS, Zhou H, Menzel L, Kumra H, Duquette M, Huang P, Baish JW, Munn LL, Ubellacker JM, Jones D, Padera TP. Lymphatic muscle cells are unique cells that undergo aging induced changes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.18.567621. [PMID: 38014141 PMCID: PMC10680808 DOI: 10.1101/2023.11.18.567621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Lymphatic muscle cells (LMCs) within the wall of collecting lymphatic vessels exhibit tonic and autonomous phasic contractions, which drive active lymph transport to maintain tissue-fluid homeostasis and support immune surveillance. Damage to LMCs disrupts lymphatic function and is related to various diseases. Despite their importance, knowledge of the transcriptional signatures in LMCs and how they relate to lymphatic function in normal and disease contexts is largely missing. We have generated a comprehensive transcriptional single-cell atlas-including LMCs-of collecting lymphatic vessels in mouse dermis at various ages. We identified genes that distinguish LMCs from other types of muscle cells, characterized the phenotypical and transcriptomic changes in LMCs in aged vessels, and uncovered a pro-inflammatory microenvironment that suppresses the contractile apparatus in advanced-aged LMCs. Our findings provide a valuable resource to accelerate future research for the identification of potential drug targets on LMCs to preserve lymphatic vessel function as well as supporting studies to identify genetic causes of primary lymphedema currently with unknown molecular explanation.
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6
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Zawieja SD, Pea GA, Broyhill SE, Bromert KH, Norton CE, Kim HJ, Li M, Castorena-Gonzalez JA, Drumm BT, Davis MJ. Lymphatic muscle cells are the innate pacemaker cells regulating mouse lymphatic collecting vessel contractions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.24.554619. [PMID: 37662284 PMCID: PMC10473772 DOI: 10.1101/2023.08.24.554619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Collecting lymphatic vessels (cLVs) exhibit spontaneous contractions with a pressure-dependent frequency, but the identity of the lymphatic pacemaker cell is still debated. By analogy to pacemakers in the GI and lower urinary tracts, proposed cLV pacemaker cells include interstitial cells of Cajal like cells (ICLC), pericytes, as well as the lymphatic muscle (LMCs) cells themselves. Here we tested the extent to which these cell types are invested into the mouse cLV wall and if any cell type exhibited morphological and functional processes characteristic of pacemaker cells: a contiguous network; spontaneous Ca2+ transients; and depolarization-induced propagated contractions. We employed inducible Cre (iCre) mouse models routinely used to target these specific cell populations including: c-kitCreERT2 to target ICLC; PdgfrβCreERT2 to target pericytes; PdgfrαCreER™ to target CD34+ adventitial fibroblast-like cells or ICLC; and Myh11CreERT2 to target LMCs. These specific inducible Cre lines were crossed to the fluorescent reporter ROSA26mT/mG, the genetically encoded Ca2+ sensor GCaMP6f, and the light-activated cation channel rhodopsin2 (ChR2). c-KitCreERT2 labeled both a sparse population of LECs and round adventitial cells that responded to the mast cell activator compound 48-80. PdgfrβCreERT2 drove recombination in both adventitial cells and LMCs, limiting its power to discriminate a pericyte specific population. PdgfrαCreER™ labeled a large population of interconnected, oak leaf-shaped cells primarily along the adventitial surface of the vessel. Titrated induction of the smooth muscle-specific Myh11CreERT2 revealed a LMC population with heterogeneous morphology. Only LMCs consistently, but heterogeneously, displayed spontaneous Ca2+ events during the diastolic period of the contraction cycle, and whose frequency was modulated in a pressure-dependent manner. Optogenetic depolarization through the expression of ChR2 by Myh11CreERT2, but not PdgfrαCreER™ or c-KitCreERT2, resulted in a propagated contraction. These findings support the conclusion that LMCs, or a subset of LMCs, are responsible for mouse cLV pacemaking.
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Affiliation(s)
- S D Zawieja
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - G A Pea
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - S E Broyhill
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - K H Bromert
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - C E Norton
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - H J Kim
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | - M Li
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
| | | | - B T Drumm
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co. Louth, A91 K584, Ireland
| | - M J Davis
- Dept. of Medical Pharmacology & Physiology, University of Missouri, Columbia, Missouri
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7
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Davis MJ, Castorena-Gonzalez JA, Zawieja SD. Electric field stimulation unmasks a subtle role for T-type calcium channels in regulating lymphatic contraction. Sci Rep 2023; 13:15862. [PMID: 37739992 PMCID: PMC10516884 DOI: 10.1038/s41598-023-42877-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 09/15/2023] [Indexed: 09/24/2023] Open
Abstract
We previously identified two isoforms of T-type, voltage-gated calcium (Cav3) channels (Cav3.1, Cav3.2) that are functionally expressed in murine lymphatic muscle cells; however, contractile tests of lymphatic vessels from single and double Cav3 knock-out (DKO) mice, exhibited nearly identical parameters of spontaneous twitch contractions as wild-type (WT) vessels, suggesting that Cav3 channels play no significant role. Here, we considered the possibility that the contribution of Cav3 channels might be too subtle to detect in standard contraction analyses. We compared the sensitivity of lymphatic vessels from WT and Cav3 DKO mice to the L-type calcium channel (Cav1.2) inhibitor nifedipine and found that the latter vessels were significantly more sensitive to inhibition, suggesting that the contribution of Cav3 channels might normally be masked by Cav1.2 channel activity. We hypothesized that shifting the resting membrane potential (Vm) of lymphatic muscle to a more negative voltage might enhance the contribution of Cav3 channels. Because even slight hyperpolarization is known to completely silence spontaneous contractions, we devised a method to evoke nerve-independent, twitch contractions from mouse lymphatic vessels using single, short pulses of electric field stimulation (EFS). TTX was present throughout to block the potential contributions of voltage-gated Na+ channels in perivascular nerves and lymphatic muscle. In WT vessels, EFS evoked single contractions that were comparable in amplitude and degree of entrainment to those occurring spontaneously. When Cav1.2 channels were blocked or deleted, only small residual EFS-evoked contractions (~ 5% of normal amplitude) were present. These residual, EFS-evoked contractions were enhanced (to 10-15%) by the KATP channel activator pinacidil (PIN) but were absent in Cav3 DKO vessels. Our results point to a subtle contribution of Cav3 channels to lymphatic contractions that can be unmasked in the absence of Cav1.2 channel activity and when the resting Vm is more hyperpolarized than normal.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, One Hospital Drive, MA415 Medical Sciences Building, Columbia, MO, 65212, USA.
| | | | - Scott D Zawieja
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, One Hospital Drive, MA415 Medical Sciences Building, Columbia, MO, 65212, USA
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8
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Kim HJ, Li M, Erlich EC, Randolph GJ, Davis MJ. ERG K + channels mediate a major component of action potential repolarization in lymphatic muscle. Sci Rep 2023; 13:14890. [PMID: 37689781 PMCID: PMC10492848 DOI: 10.1038/s41598-023-41995-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 09/04/2023] [Indexed: 09/11/2023] Open
Abstract
Smooth muscle cells in the walls of collecting lymphatic vessels fire spontaneous action potentials (APs), which conduct rapidly over the muscle layer to initiate contractions that propel lymph. Several ion channels have been implicated in the currents underlying the AP spike and the preceding diastolic depolarization, but the molecular identities of K+ channels involved in AP repolarization are unknown. Based on previous studies of other rhythmically active smooth muscles, we hypothesized that ether-a-go-go related gene (ERG) K+ channels (Kv11) play an important role in repolarization of the AP in lymphatic muscle. Message for one or more ERG channel isoforms was detected by RT-PCR analysis of lymphatic vessels from mice, rats and humans. Membrane potential recordings in smooth muscle cells of rat and human lymphatics revealed that nanomolar concentrations of ERG-1 inhibitors (E-4031 and BeKm-1) prolonged the duration of the AP plateau (normally ~ 1 s in duration) and induced multiple spikes, whereas ERG-1 activators (ICA-105574 and RPR-260243) shortened the plateau and could completely inhibit spontaneous APs. At relatively high inhibitor concentrations, the AP plateau duration lasted as long as 24 s. ERG activators reversed the effects of ERG inhibitors and vice-versa. In pressure myograph studies, ERG channel inhibition prolonged the diastolic repolarization phase of the contraction cycle and reduced the frequency of spontaneous contractions. This is the first evidence for a specific K+ channel contributing to the AP in lymphatic muscle. Our results imply that lymphatic contractile dysfunction may occur in long QT type II patients with mutations that result in ERG channel loss-of-function or impaired trafficking of the channel to the cell membrane.
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Affiliation(s)
- Hae Jin Kim
- Department of Medical Pharmacology & Physiology, University of Missouri, One Hospital Drive, MA415 Medical Sciences Building, Columbia, MO, 65212, USA
| | - Min Li
- Department of Medical Pharmacology & Physiology, University of Missouri, One Hospital Drive, MA415 Medical Sciences Building, Columbia, MO, 65212, USA
| | - Emma C Erlich
- Department of Pathology and Immunology, Washington University, St Louis, MO, USA
| | - Gwendalyn J Randolph
- Department of Pathology and Immunology, Washington University, St Louis, MO, USA
| | - Michael J Davis
- Department of Medical Pharmacology & Physiology, University of Missouri, One Hospital Drive, MA415 Medical Sciences Building, Columbia, MO, 65212, USA.
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9
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Davis MJ, Castorena-Gonzalez JA, Zawieja SD. Electric field stimulation unmasks a subtle role for T-type calcium channels in regulating lymphatic contraction. RESEARCH SQUARE 2023:rs.3.rs-2938440. [PMID: 37333279 PMCID: PMC10275045 DOI: 10.21203/rs.3.rs-2938440/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
We previously identified two isoforms of T-type, voltage-gated calcium (Ca v 3) channels (Ca v 3.1, Ca v 3.2) that are functionally expressed in murine lymphatic muscle cells; however, contractile tests of lymphatic vessels from single and double Ca v 3 knock-out (DKO) mice, exhibited nearly identical parameters of spontaneous twitch contractions as wild-type (WT) vessels, suggesting that Ca v 3 channels play no significant role. Here, we considered the possibility that the contribution of Ca v 3 channels might be too subtle to detect in standard contraction analyses. We compared the sensitivity of lymphatic vessels from WT and Ca v 3 DKO mice to the L-type calcium channel (Ca v 1.2) inhibitor nifedipine and found that the latter vessels were significantly more sensitive to inhibition, suggesting that the contribution of Ca v 3 channels might normally be masked by Ca v 1.2 channel activity. We hypothesized that shifting the resting membrane potential (Vm) of lymphatic muscle to a more negative voltage might enhance the contribution of Ca v 3 channels. Because even slight hyperpolarization is known to completely silence spontaneous contractions, we devised a method to evoke nerve-independent, twitch contractions from mouse lymphatic vessels using single, short pulses of electric field stimulation (EFS). TTX was present throughout to block the potential contributions of voltage-gated Na + channels in perivascular nerves and lymphatic muscle. In WT vessels, EFS evoked single contractions that were comparable in amplitude and degree of entrainment to those occurring spontaneously. When Ca v 1.2 channels were blocked or deleted, only small residual EFS-evoked contractions (~ 5% of normal amplitude) were present. These residual, EFS-evoked contractions were enhanced (to 10-15%) by the K ATP channel activator pinacidil (PIN) but were absent in Ca v 3 DKO vessels. Our results point to a subtle contribution of Ca v 3 channels to lymphatic contractions that can be unmasked in the absence of Ca v 1.2 channel activity and when the resting Vm is more hyperpolarized than normal.
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10
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Kenney HM, Peng Y, de Mesy Bentley KL, Xing L, Ritchlin CT, Schwarz EM. The Enigmas of Lymphatic Muscle Cells: Where Do They Come From, How Are They Maintained, and Can They Regenerate? Curr Rheumatol Rev 2023; 19:246-259. [PMID: 36705238 PMCID: PMC10257750 DOI: 10.2174/1573397119666230127144711] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 10/29/2022] [Accepted: 12/02/2022] [Indexed: 01/28/2023]
Abstract
Lymphatic muscle cell (LMC) contractility and coverage of collecting lymphatic vessels (CLVs) are integral to effective lymphatic drainage and tissue homeostasis. In fact, defects in lymphatic contractility have been identified in various conditions, including rheumatoid arthritis, inflammatory bowel disease, and obesity. However, the fundamental role of LMCs in these pathologic processes is limited, primarily due to the difficulty in directly investigating the enigmatic nature of this poorly characterized cell type. LMCs are a unique cell type that exhibit dual tonic and phasic contractility with hybrid structural features of both vascular smooth muscle cells (VSMCs) and cardiac myocytes. While advances have been made in recent years to better understand the biochemistry and function of LMCs, central questions regarding their origins, investiture into CLVs, and homeostasis remain unanswered. To summarize these discoveries, unexplained experimental results, and critical future directions, here we provide a focused review of current knowledge and open questions related to LMC progenitor cells, recruitment, maintenance, and regeneration. We also highlight the high-priority research goal of identifying LMC-specific genes towards genetic conditional- inducible in vivo gain and loss of function studies. While our interest in LMCs has been focused on understanding lymphatic dysfunction in an arthritic flare, these concepts are integral to the broader field of lymphatic biology, and have important potential for clinical translation through targeted therapeutics to control lymphatic contractility and drainage.
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Grants
- R01AG059775,R01AG059775,R01AG059775 NIA NIH HHS
- R01AR056702,R01AR069000,T32AR076950,P30AR069655,R01AR056702,R01AR069000,P30AR069655,T32AR076950,R01AR056702,R01AR069000,T32AR076950,P30AR069655 NIAMS NIH HHS
- P30 AR069655 NIAMS NIH HHS
- R01 AR069000 NIAMS NIH HHS
- T32 GM007356 NIGMS NIH HHS
- R01 AG059775 NIA NIH HHS
- T32GM007356,T32GM007356,T32GM007356,T32GM007356 NIGMS NIH HHS
- T32 AR076950 NIAMS NIH HHS
- R01 AR056702 NIAMS NIH HHS
- F30 AG076326 NIA NIH HHS
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Affiliation(s)
- H. Mark Kenney
- Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Ave, Box 665, Rochester, NY, 14642, USA
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Yue Peng
- Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Ave, Box 665, Rochester, NY, 14642, USA
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Karen L. de Mesy Bentley
- Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Ave, Box 665, Rochester, NY, 14642, USA
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
- Department of Orthopaedics, University of Rochester Medical Center, Rochester, NY, USA
| | - Lianping Xing
- Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Ave, Box 665, Rochester, NY, 14642, USA
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Christopher T. Ritchlin
- Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Ave, Box 665, Rochester, NY, 14642, USA
- Department of Medicine, Division of Allergy, Immunology, Rheumatology, University of Rochester Medical Center, Rochester, NY, USA
| | - Edward M. Schwarz
- Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Ave, Box 665, Rochester, NY, 14642, USA
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
- Department of Medicine, Division of Allergy, Immunology, Rheumatology, University of Rochester Medical Center, Rochester, NY, USA
- Department of Orthopaedics, University of Rochester Medical Center, Rochester, NY, USA
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11
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Jablon KL, Akerstrom VL, Li M, Braun SE, Norton CE, Castorena-Gonzalez JA. Isolation and short-term culturing of primary lymphatic endothelial cells from collecting lymphatics: A techniques study. Microcirculation 2023; 30:e12778. [PMID: 35879879 PMCID: PMC9873843 DOI: 10.1111/micc.12778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 07/11/2022] [Accepted: 07/21/2022] [Indexed: 01/27/2023]
Abstract
OBJECTIVE To develop an experimental method for routine isolation and short-term culture of primary lymphatic endothelial cells from specific collecting vessels. METHODS Lymphatic endothelial cell tubes (LECTs) were isolated from micro-dissected collecting vessels. LECTs were allowed to attach and grow for ~3 weeks before being passaged. Non-purified cultures were partially characterized by immunofluorescence and RT-PCR at passages 1-2. RESULTS The method was validated in cultures of primary lymphatic endothelial cells (LECs) from male and female mice. After 1 or 2 passages, >60% of the LECs maintained expression of Prox1. Expression of 22 different genes was assessed using RT-PCR. Prox1, Vegfr3, eNos, Cdh5, Pecam1, Cx43, Cx37, and Cx47, among others, were expressed in these short-term cultured LECs, while Myh11, Cnn1, Desmin, and Cd11b were not detected. Prox1 expression, as determined by western blotting, was similar in cultured LECs from age-matched male and female mice. Confocal imaging of intracellular calcium in cultures of primary LECs from Cdh5-GCaMP8 mice demonstrated that a functional phenotype was maintained, similar to lymphatic endothelial cells in freshly isolated vessels. CONCLUSIONS This method provides an innovative tool for routine isolation and study of primary LECs from specific collecting lymphatic vessels from any mouse, and in fact, from other species.
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Affiliation(s)
- Kelli L. Jablon
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Victoria L. Akerstrom
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Min Li
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, USA
| | - Stephen E. Braun
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, LA, USA
- Division of Immunology, Tulane National Primate Research Center, Tulane University School of Medicine, Covington, LA, USA
| | - Charles E. Norton
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, USA
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12
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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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13
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Davis MJ, Kim HJ, Nichols CG. K ATP channels in lymphatic function. Am J Physiol Cell Physiol 2022; 323:C1018-C1035. [PMID: 35785984 PMCID: PMC9550566 DOI: 10.1152/ajpcell.00137.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 11/22/2022]
Abstract
KATP channels function as negative regulators of active lymphatic pumping and lymph transport. This review summarizes and critiques the evidence for the expression of specific KATP channel subunits in lymphatic smooth muscle and endothelium, the roles that they play in normal lymphatic function, and their possible involvement in multiple diseases, including metabolic syndrome, lymphedema, and Cantú syndrome. For each of these topics, suggestions are made for directions for future research.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, Missouri
| | - Hae Jin Kim
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, Missouri
| | - Colin G Nichols
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri
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14
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Kenney HM, Peng Y, Bell RD, Wood RW, Xing L, Ritchlin CT, Schwarz EM. Persistent popliteal lymphatic muscle cell coverage defects despite amelioration of arthritis and recovery of popliteal lymphatic vessel function in TNF-Tg mice following anti-TNF therapy. Sci Rep 2022; 12:12751. [PMID: 35882971 PMCID: PMC9325893 DOI: 10.1038/s41598-022-16884-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 07/18/2022] [Indexed: 11/20/2022] Open
Abstract
While rheumatoid arthritis patients and tumor necrosis factor transgenic (TNF-Tg) mice with inflammatory-erosive arthritis display lymphatic drainage deficits, the mechanisms responsible remain unknown. As ultrastructural studies of joint-draining popliteal lymphatic vessels (PLVs) in TNF-Tg mice revealed evidence of lymphatic muscle cell (LMC) damage, we aimed to evaluate PLV-LMC coverage in TNF-Tg mice. We tested the hypothesis that alpha smooth muscle actin (αSMA)+ PLV-LMC coverage decreases with severe inflammatory-erosive arthritis, and is recovered by anti-TNF therapy facilitated by increased PLV-LMC turnover during amelioration of joint disease. TNF-Tg mice with established disease received anti-TNF monoclonal antibody (mAb) or placebo IgG isotype control mAb therapy (n = 5) for 6-weeks, while wild-type (WT) littermates (n = 8) received vehicle (PBS). Bromodeoxyuridine (BrdU) was also administered daily during the treatment period to monitor PLV-LMC turnover. Effective anti-TNF therapy was confirmed by longitudinal assessment of popliteal lymph node (PLN) volume via ultrasound, PLV contraction frequency via near-infrared imaging of indocyanine green, and ankle bone volumes via micro-computed tomography (micro-CT). Terminal knee micro-CT, and ankle and knee histology were also performed. PLVs were immunostained for αSMA and BrdU to evaluate PLV-LMC coverage and turnover, respectively, via whole-mount fluorescent microscopy. Anti-TNF therapy reduced PLN volume, increased talus and patella bone volumes, and reduced tarsal and knee synovial areas compared to placebo treated TNF-Tg mice (p < 0.05), as expected. Anti-TNF therapy also increased PLV contraction frequency at 3-weeks (from 0.81 ± 1.0 to 3.2 ± 2.0 contractions per minute, p < 0.05). However, both anti-TNF and placebo treated TNF-Tg mice exhibited significantly reduced αSMA+ PLV-LMC coverage compared to WT (p < 0.05). There was no correlation of αSMA+ PLV-LMC coverage restoration with amelioration of inflammatory-erosive arthritis. Similarly, there was no difference in PLV-LMC turnover measured by BrdU labeling between WT, TNF-Tg placebo, and TNF-Tg anti-TNF groups with an average of < 1% BrdU+ PLV-LMCs incorporated per week. Taken together these results demonstrate that PLV-LMC turnover in adult mice is limited, and that recovery of PLV function during amelioration of inflammatory-erosive arthritis occurs without restoration of αSMA+ LMC coverage. Future studies are warranted to investigate the direct and indirect effects of chronic TNF exposure, and the role of proximal inflammatory cells on PLV contractility.
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Affiliation(s)
- H Mark Kenney
- Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Ave, Box 665, Rochester, NY, 14642, USA
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Yue Peng
- Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Ave, Box 665, Rochester, NY, 14642, USA
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Richard D Bell
- Department of Research, Hospital for Special Surgery, New York, NY, USA
| | - Ronald W Wood
- Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Ave, Box 665, Rochester, NY, 14642, USA
- Department of Obstetrics and Gynecology, University of Rochester Medical Center, Rochester, NY, USA
- Department of Neuroscience, University of Rochester Medical Center, Rochester, NY, USA
- Department of Urology, University of Rochester Medical Center, Rochester, NY, USA
| | - Lianping Xing
- Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Ave, Box 665, Rochester, NY, 14642, USA
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Christopher T Ritchlin
- Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Ave, Box 665, Rochester, NY, 14642, USA
- Department of Medicine, Division of Allergy, Immunology, Rheumatology, University of Rochester Medical Center, Rochester, NY, USA
| | - Edward M Schwarz
- Center for Musculoskeletal Research, University of Rochester Medical Center, 601 Elmwood Ave, Box 665, Rochester, NY, 14642, USA.
- Department of Pathology & Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA.
- Department of Urology, University of Rochester Medical Center, Rochester, NY, USA.
- Department of Medicine, Division of Allergy, Immunology, Rheumatology, University of Rochester Medical Center, Rochester, NY, USA.
- Department of Orthopaedics, University of Rochester Medical Center, Rochester, NY, USA.
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15
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Lee Y, Zawieja SD, Muthuchamy M. Lymphatic Collecting Vessel: New Perspectives on Mechanisms of Contractile Regulation and Potential Lymphatic Contractile Pathways to Target in Obesity and Metabolic Diseases. Front Pharmacol 2022; 13:848088. [PMID: 35355722 PMCID: PMC8959455 DOI: 10.3389/fphar.2022.848088] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 02/17/2022] [Indexed: 01/19/2023] Open
Abstract
Obesity and metabolic syndrome pose a significant risk for developing cardiovascular disease and remain a critical healthcare challenge. Given the lymphatic system's role as a nexus for lipid absorption, immune cell trafficking, interstitial fluid and macromolecule homeostasis maintenance, the impact of obesity and metabolic disease on lymphatic function is a burgeoning field in lymphatic research. Work over the past decade has progressed from the association of an obese phenotype with Prox1 haploinsufficiency and the identification of obesity as a risk factor for lymphedema to consistent findings of lymphatic collecting vessel dysfunction across multiple metabolic disease models and organisms and characterization of obesity-induced lymphedema in the morbidly obese. Critically, recent findings have suggested that restoration of lymphatic function can also ameliorate obesity and insulin resistance, positing lymphatic targeted therapies as relevant pharmacological interventions. There remain, however, significant gaps in our understanding of lymphatic collecting vessel function, particularly the mechanisms that regulate the spontaneous contractile activity required for active lymph propulsion and lymph return in humans. In this article, we will review the current findings on lymphatic architecture and collecting vessel function, including recent advances in the ionic basis of lymphatic muscle contractile activity. We will then discuss lymphatic dysfunction observed with metabolic disruption and potential pathways to target with pharmacological approaches to improve lymphatic collecting vessel function.
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Affiliation(s)
- Yang Lee
- Department of Medical Physiology, College of Medicine, Texas A&M University, Bryan, TX, United States
| | - Scott D Zawieja
- Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO, United States
| | - Mariappan Muthuchamy
- Department of Medical Physiology, College of Medicine, Texas A&M University, Bryan, TX, United States
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16
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Hancock EJ, Zawieja SD, Macaskill C, Davis MJ, Bertram CD. Modelling the coupling of the M-clock and C-clock in lymphatic muscle cells. Comput Biol Med 2022; 142:105189. [PMID: 34995957 PMCID: PMC9132416 DOI: 10.1016/j.compbiomed.2021.105189] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 12/22/2021] [Accepted: 12/27/2021] [Indexed: 01/01/2023]
Abstract
Chronic dysfunction of the lymphatic vascular system results in fluid accumulation between cells: lymphoedema. The condition is commonly acquired secondary to diseases such as cancer or the associated therapies. The primary driving force for fluid return through the lymphatic vasculature is provided by contractions of the muscularized lymphatic collecting vessels, driven by electrochemical oscillations. However, there is an incomplete understanding of the molecular and bioelectric mechanisms involved in lymphatic muscle cell excitation, hampering the development and use of pharmacological therapies. Modelling in silico has contributed greatly to understanding the contributions of specific ion channels to the cardiac action potential, but modelling of these processes in lymphatic muscle remains limited. Here, we propose a model of oscillations in the membrane voltage (M-clock) and intracellular calcium concentrations (C-clock) of lymphatic muscle cells. We modify a model by Imtiaz and colleagues to enable the M-clock to drive the C-clock oscillations. This approach differs from typical models of calcium oscillators in lymphatic and related cell types, but is required to fit recent experimental data. We include an additional voltage dependence in the gating variable control for the L-type calcium channel, enabling the M-clock to oscillate independently of the C-clock. We use phase-plane analysis to show that these M-clock oscillations are qualitatively similar to those of a generalised FitzHugh-Nagumo model. We also provide phase plane analysis to understand the interaction of the M-clock and C-clock oscillations. The model and methods have the potential to help determine mechanisms and find targets for pharmacological treatment of lymphoedema.
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Affiliation(s)
- E J Hancock
- School of Mathematics & Statistics, University of Sydney, NSW, 2006, Australia
| | - S D Zawieja
- Dept. of Medical Pharmacology & Physiology, Univ. of Missouri, Columbia, MI, 65212, USA
| | - C Macaskill
- School of Mathematics & Statistics, University of Sydney, NSW, 2006, Australia
| | - M J Davis
- Dept. of Medical Pharmacology & Physiology, Univ. of Missouri, Columbia, MI, 65212, USA
| | - C D Bertram
- School of Mathematics & Statistics, University of Sydney, NSW, 2006, Australia.
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17
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Selahi A, Fernando T, Chakraborty S, Muthuchamy M, Zawieja DC, Jain A. Lymphangion-chip: a microphysiological system which supports co-culture and bidirectional signaling of lymphatic endothelial and muscle cells. LAB ON A CHIP 2021; 22:121-135. [PMID: 34850797 PMCID: PMC9761984 DOI: 10.1039/d1lc00720c] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The pathophysiology of several lymphatic diseases, such as lymphedema, depends on the function of lymphangions that drive lymph flow. Even though the signaling between the two main cellular components of a lymphangion, endothelial cells (LECs) and muscle cells (LMCs), is responsible for crucial lymphatic functions, there are no in vitro models that have included both cell types. Here, a fabrication technique (gravitational lumen patterning or GLP) is developed to create a lymphangion-chip. This organ-on-chip consists of co-culture of a monolayer of endothelial lumen surrounded by multiple and uniformly thick layers of muscle cells. The platform allows construction of a wide range of luminal diameters and muscular layer thicknesses, thus providing a toolbox to create variable anatomy. In this device, lymphatic muscle cells align circumferentially while endothelial cells aligned axially under flow, as only observed in vivo in the past. This system successfully characterizes the dynamics of cell size, density, growth, alignment, and intercellular gap due to co-culture and shear. Finally, exposure to pro-inflammatory cytokines reveals that the device could facilitate the regulation of endothelial barrier function through the lymphatic muscle cells. Therefore, this bioengineered platform is suitable for use in preclinical research of lymphatic and blood mechanobiology, inflammation, and translational outcomes.
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Affiliation(s)
- Amirali Selahi
- Department of Biomedical Engineering, College of Engineering, Texas A&M University, 101 Bizzell Street College Station, TX, 77843, USA.
| | - Teshan Fernando
- Department of Biomedical Engineering, College of Engineering, Texas A&M University, 101 Bizzell Street College Station, TX, 77843, USA.
| | - Sanjukta Chakraborty
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Bryan, TX, USA
| | - Mariappan Muthuchamy
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Bryan, TX, USA
| | - David C Zawieja
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Bryan, TX, USA
| | - Abhishek Jain
- Department of Biomedical Engineering, College of Engineering, Texas A&M University, 101 Bizzell Street College Station, TX, 77843, USA.
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Bryan, TX, USA
- Department of Cardiovascular Sciences, Houston Methodist Academic Institute, Houston, TX, USA
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18
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Kim HJ, Li M, Nichols CG, Davis MJ. Large-conductance calcium-activated K + channels, rather than K ATP channels, mediate the inhibitory effects of nitric oxide on mouse lymphatic pumping. Br J Pharmacol 2021; 178:4119-4136. [PMID: 34213021 PMCID: PMC9793343 DOI: 10.1111/bph.15602] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 05/19/2021] [Accepted: 06/07/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND AND PURPOSE KATP channels are negative regulators of lymphatic vessel excitability and contractility and are proposed to be targets for immune cell products that inhibit lymph transport. Previous studies in rat and guinea pig mesenteric lymphatics found that NO-mediated inhibition of lymphatic contraction was prevented or reversed by the KATP channel inhibitor, glibenclamide. We revisited this hypothesis using mouse lymphatic vessels and KATP channel knockout mice. EXPERIMENTAL APPROACH Mouse popliteal lymphatics were isolated, and contractility was assessed using pressure myography. K+ channel expression was determined by PCR analysis of FACS-purified lymphatic smooth muscle cells. KEY RESULTS The NO-producing agonist, ACh, and the NO donor, NONOate, both produced dose-dependent inhibition of spontaneous lymphatic contractions that were blocked by the soluble GC inhibitor, ODQ, or the PKG inhibitor, Rp-8-Br-PET-cGMPS. Surprisingly, the inhibitory effects of both were preserved in Kir 6.1-/- vessels, suggesting that KATP channels did not mediate NO-induced responses. We hypothesized a role for BK channels, given their prominence in arterial smooth muscle. Indeed, BK channels were expressed in mouse lymphatic smooth muscle and NS11021 (a BK channel activator) caused dilation and reduced contraction frequency, whereas iberiotoxin and penitrem A (BK channel inhibitors) produced right-ward shifts in NONOate concentration-response curves. CONCLUSION AND IMPLICATIONS Inhibition of mouse lymphatic contractions by NO primarily involves activation of BK channels, rather than KATP channels. Thus, BK channels are a potential target for therapeutic reversal of lymph pump inhibition by NO generated by immune cell activation of iNOS in chronic lymphoedema.
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Affiliation(s)
- Hae Jin Kim
- Department of Medical Pharmacology & Physiology, University of Missouri, Columbia, MO
| | - Min Li
- Department of Medical Pharmacology & Physiology, University of Missouri, Columbia, MO
| | - Colin G. Nichols
- Department of Cell Biology & Physiology, Washington University, St. Louis, MO
| | - Michael J. Davis
- Department of Medical Pharmacology & Physiology, University of Missouri, Columbia, MO
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19
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Elich H, Barrett A, Shankar V, Fogelson AL. Pump efficacy in a two-dimensional, fluid-structure interaction model of a chain of contracting lymphangions. Biomech Model Mechanobiol 2021; 20:1941-1968. [PMID: 34275062 DOI: 10.1007/s10237-021-01486-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 06/26/2021] [Indexed: 11/25/2022]
Abstract
The transport of lymph through the lymphatic vasculature is the mechanism for returning excess interstitial fluid to the circulatory system, and it is essential for fluid homeostasis. Collecting lymphatic vessels comprise a significant portion of the lymphatic vasculature and are divided by valves into contractile segments known as lymphangions. Despite its importance, lymphatic transport in collecting vessels is not well understood. We present a computational model to study lymph flow through chains of valved, contracting lymphangions. We used the Navier-Stokes equations to model the fluid flow and the immersed boundary method to handle the two-way, fluid-structure interaction in 2D, non-axisymmetric simulations. We used our model to evaluate the effects of chain length, contraction style, and adverse axial pressure difference (AAPD) on cycle-mean flow rates (CMFRs). In the model, longer lymphangion chains generally yield larger CMFRs, and they fail to generate positive CMFRs at higher AAPDs than shorter chains. Simultaneously contracting pumps generate the largest CMFRs at nearly every AAPD and for every chain length. Due to the contraction timing and valve dynamics, non-simultaneous pumps generate lower CMFRs than the simultaneous pumps; the discrepancy diminishes as the AAPD increases. Valve dynamics vary with the contraction style and exhibit hysteretic opening and closing behaviors. Our model provides insight into how contraction propagation affects flow rates and transport through a lymphangion chain.
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Affiliation(s)
- Hallie Elich
- Department of Mathematics, University of Utah, Salt Lake City, UT, USA.
| | - Aaron Barrett
- Department of Mathematics, University of Utah, Salt Lake City, UT, USA
| | - Varun Shankar
- School of Computing, University of Utah, Salt Lake City, UT, USA
| | - Aaron L Fogelson
- Department of Mathematics, University of Utah, Salt Lake City, UT, USA
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
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20
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Castorena-Gonzalez JA, Li M, Davis MJ. Effects of Elevated Downstream Pressure and the Role of Smooth Muscle Cell Coupling through Connexin45 on Lymphatic Pacemaking. Biomolecules 2020; 10:biom10101424. [PMID: 33050046 PMCID: PMC7600536 DOI: 10.3390/biom10101424] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/03/2020] [Accepted: 10/06/2020] [Indexed: 12/27/2022] Open
Abstract
Lymphatic vessels rely on spontaneous lymphatic muscle cell (LMC) contractions and one-way intraluminal valves to efficiently pump lymph and return it into the bloodstream. Intraluminal pressure is known to regulate the contractile function of lymphatics, with pressure elevation leading to increased contraction frequency and decreased amplitude. Contractions are normally initiated by a dominant pacemaker and are highly entrained among strongly coupled LMCs. Previously, we found that connexin45 is the major connexin isoform mediating LMC-LMC electrical coupling. Lymphatics from mice lacking smooth muscle connexin45 display uncoordinated, impaired contractions. Here, we utilized this connexin45-deficient model, pressure myography, and recently developed, novel analytical tools to assess the effects of elevated downstream pressure on the number, location, and frequency of lymphatic pacemakers. Our results show that, in vessels from healthy controls, an increase in downstream pressure resulted in the recruitment/development of new pacemakers and increased contractile frequency while a dominant pacemaker continued to be observed. In contrast, vessels from connexin45-deficient mice displayed significantly more pacemakers, but none were dominant; this worsened with elevated downstream pressure. These results suggest a potential protective mechanism through which the lymphatic vasculature adapts to transient increases in downstream pressure, but which may not be sustained in scenarios with chronic elevated downstream pressure.
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Affiliation(s)
- Jorge A. Castorena-Gonzalez
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO 65212, USA; (J.A.C.-G.); (M.L.)
- Department of Pharmacology, School of Medicine, Tulane University, New Orleans, LA 70112, USA
| | - Min Li
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO 65212, USA; (J.A.C.-G.); (M.L.)
| | - Michael J. Davis
- Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO 65212, USA; (J.A.C.-G.); (M.L.)
- Correspondence: ; Tel.: +1-(573)-884-5181
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21
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Davis MJ, Kim HJ, Zawieja SD, Castorena-Gonzalez JA, Gui P, Li M, Saunders BT, Zinselmeyer BH, Randolph GJ, Remedi MS, Nichols CG. Kir6.1-dependent K ATP channels in lymphatic smooth muscle and vessel dysfunction in mice with Kir6.1 gain-of-function. J Physiol 2020; 598:3107-3127. [PMID: 32372450 DOI: 10.1113/jp279612] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 05/01/2020] [Indexed: 02/06/2023] Open
Abstract
KEY POINTS Spontaneous contractions are essential for normal lymph transport and these contractions are exquisitely sensitive to the KATP channel activator pinacidil. KATP channel Kir6.1 and SUR2B subunits are expressed in mouse lymphatic smooth muscle (LSM) and form functional KATP channels as verified by electrophysiological techniques. Global deletion of Kir6.1 or SUR2 subunits results in severely impaired lymphatic contractile responses to pinacidil. Smooth muscle-specific expression of Kir6.1 gain-of-function mutant (GoF) subunits results in profound lymphatic contractile dysfunction and LSM hyperpolarization that is partially rescued by the KATP inhibitor glibenclamide. In contrast, lymphatic endothelial-specific expression of Kir6.1 GoF has essentially no effect on lymphatic contractile function. The high sensitivity of LSM to KATP channel GoF offers an explanation for the lymphoedema observed in patients with Cantú syndrome, a disorder caused by gain-of-function mutations in genes encoding Kir6.1 or SUR2, and suggests that glibenclamide may be an appropriate therapeutic agent. ABSTRACT This study aimed to understand the functional expression of KATP channel subunits in distinct lymphatic cell types, and assess the consequences of altered KATP channel activity on lymphatic pump function. KATP channel subunits Kir6.1 and SUR2B were expressed in mouse lymphatic muscle by PCR, but only Kir6.1 was expressed in lymphatic endothelium. Spontaneous contractions of popliteal lymphatics from wild-type (WT) (C57BL/6J) mice, assessed by pressure myography, were very sensitive to inhibition by the SUR2-specific KATP channel activator pinacidil, which hyperpolarized both mouse and human lymphatic smooth muscle (LSM). In vessels from mice with deletion of Kir6.1 (Kir6.1-/- ) or SUR2 (SUR2[STOP]) subunits, contractile parameters were not significantly different from those of WT vessels, suggesting that basal KATP channel activity in LSM is not an essential component of the lymphatic pacemaker, and does not exert a strong influence over contractile strength. However, these vessels were >100-fold less sensitive than WT vessels to pinacidil. Smooth muscle-specific expression of a Kir6.1 gain-of-function (GoF) subunit resulted in severely impaired lymphatic contractions and hyperpolarized LSM. Membrane potential and contractile activity was partially restored by the KATP channel inhibitor glibenclamide. In contrast, lymphatic endothelium-specific expression of Kir6.1 GoF subunits had negligible effects on lymphatic contraction frequency or amplitude. Our results demonstrate a high sensitivity of lymphatic contractility to KATP channel activators through activation of Kir6.1/SUR2-dependent channels in LSM. In addition, they offer an explanation for the lymphoedema observed in patients with Cantú syndrome, a disorder caused by gain-of-function mutations in genes encoding Kir6.1/SUR2.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, 65212, USA
| | - Hae Jin Kim
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, 65212, USA
| | - Scott D Zawieja
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, 65212, USA
| | - Jorge A Castorena-Gonzalez
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, 65212, USA
| | - Peichun Gui
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, 65212, USA
| | - Min Li
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, 65212, USA
| | - Brian T Saunders
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Bernd H Zinselmeyer
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Gwendalyn J Randolph
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Maria S Remedi
- Department of Medicine, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Colin G Nichols
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, MO, 63110, USA
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Pogoda K, Kameritsch P. Molecular regulation of myoendothelial gap junctions. Curr Opin Pharmacol 2019; 45:16-22. [DOI: 10.1016/j.coph.2019.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 02/14/2019] [Accepted: 03/15/2019] [Indexed: 11/16/2022]
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Zawieja SD, Castorena JA, Gui P, Li M, Bulley SA, Jaggar JH, Rock JR, Davis MJ. Ano1 mediates pressure-sensitive contraction frequency changes in mouse lymphatic collecting vessels. J Gen Physiol 2019; 151:532-554. [PMID: 30862712 PMCID: PMC6445586 DOI: 10.1085/jgp.201812294] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 02/06/2019] [Indexed: 12/16/2022] Open
Abstract
Lymphatic collecting vessels exhibit spontaneous contractions with a pressure-dependent contraction frequency. The initiation of contraction has been proposed to be mediated by the activity of a Ca2+-activated Cl- channel (CaCC). Here, we show that the canonical CaCC Anoctamin 1 (Ano1, TMEM16a) plays an important role in lymphatic smooth muscle pacemaking. We find that isolated murine lymphatic muscle cells express Ano1, and demonstrate functional CaCC currents that can be inhibited by the Ano1 inhibitor benzbromarone. These currents are absent in lymphatic muscle cells from Cre transgenic mouse lines targeted for Ano1 genetic deletion in smooth muscle. We additionally show that loss of functional Ano1 in murine inguinal-axillary lymphatic vessels, whether through genetic manipulation or pharmacological inhibition, results in an impairment of the pressure-frequency relationship that is attributable to a hyperpolarized resting membrane potential and a significantly depressed diastolic depolarization rate preceding each action potential. These changes are accompanied by alterations in action potential shape and duration, and a reduced duration but increased amplitude of the action potential-induced global "Ca2+ flashes" that precede lymphatic contractions. These findings suggest that an excitatory Cl- current provided by Ano1 is critical for mediating the pressure-sensitive contractile response and is a major component of the murine lymphatic action potential.
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Affiliation(s)
- Scott D Zawieja
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO
| | - Jorge A Castorena
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO
| | - Peichun Gui
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO
| | - Min Li
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO
| | - Simon A Bulley
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN
| | - Jonathan H Jaggar
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN
| | - Jason R Rock
- Department of Medicine, Boston University School of Medicine, Boston, MA
| | - Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO
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