1
|
Solari E, Marcozzi C, Negrini D, Moriondo A. Fluid Osmolarity Acutely and Differentially Modulates Lymphatic Vessels Intrinsic Contractions and Lymph Flow. Front Physiol 2018; 9:871. [PMID: 30026707 PMCID: PMC6041695 DOI: 10.3389/fphys.2018.00871] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/18/2018] [Indexed: 12/19/2022] Open
Abstract
Lymph formation and propulsion rely on an extrinsic mechanism based on the forces that surrounding tissues exert upon the vessel wall and lumen and an intrinsic mechanism based on spontaneous, rhythmic contractions of the lymphatic muscle layer of collecting vessels. The two spontaneous pacemakers described in literature involve chloride-dependent depolarizations (STDs) and If-like currents, both giving rise to a variable contraction frequency (fc) of lymphatic vessels functional units (lymphangions). Several stimuli have been shown to modulate fc, such as temperature, shear stress, and several tissue chemical modulators (prostaglandins, norepinephrine, acetylcholine, substance P, and others). However, no detailed description is present in literature on the acute modulation of fc by means of osmolarity change of the surrounding interstitial space. Using a well-developed ex-vivo rat diaphragmatic preparation, in which osmolarity was changed by varying the concentration of D-mannitol in the perfusing solution and in later experiments the concentration of NaCl and then of Na+ and Cl− ions separately by ionic substitution, we provide detailed experimental evidences that a stepwise increase in osmolarity from control value (308 mOsm) up to 324 mOsm caused a reduction of fc down to ~-70% within the first 14 min, and that a stepwise decrease in osmolarity up to 290 mOsm induced an early fc increase to ~+34% of control, followed by a decline to an fc of ~-18% of control value. These variations were more dramatic when the same osmolarity changes were obtained by varying NaCl and/or Na+ or Cl− ions concentration, which caused an almost complete arrest of spontaneous contractility within 14 min from the application. Diastolic and systolic diameters and stroke volume were not affected by osmolarity changes, so that modulation of lymph flow closely followed that of fc. Modulation of lymph flow secondary to osmolarity changes is relevant if one considers that interstitial fluid balance is also dependent upon lymph drainage, and thus it is possible that, at least in the acute phase following variations of interstitial fluid osmolarity, its volume control might eventually be impaired due to the reduced or in the worst scenario null lymph drainage.
Collapse
Affiliation(s)
- Eleonora Solari
- Department of Medicine and Surgery, Università degli Studi dell'Insubria, Varese, Italy
| | - Cristiana Marcozzi
- Department of Medicine and Surgery, Università degli Studi dell'Insubria, Varese, Italy
| | - Daniela Negrini
- Department of Medicine and Surgery, Università degli Studi dell'Insubria, Varese, Italy
| | - Andrea Moriondo
- Department of Medicine and Surgery, Università degli Studi dell'Insubria, Varese, Italy
| |
Collapse
|
2
|
Ma MM, Lin CX, Liu CZ, Gao M, Sun L, Tang YB, Zhou JG, Wang GL, Guan YY. Threonine532 phosphorylation in ClC-3 channels is required for angiotensin II-induced Cl(-) current and migration in cultured vascular smooth muscle cells. Br J Pharmacol 2016; 173:529-44. [PMID: 26562480 DOI: 10.1111/bph.13385] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 10/11/2015] [Accepted: 10/25/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE Angiotensin II (AngII) induces migration and growth of vascular smooth muscle cell (VSMC), which is responsible for vascular remodelling in some cardiovascular diseases. Ang II also activates a Cl(-) current, but the underlying mechanism is not clear. EXPERIMENTAL APPROACH The A10 cell line and primary cultures of VSMC from control, ClC-3 channel null mice and WT mice made hypertensive with AngII infusions were used. Techniques employed included whole-cell patch clamp, co-immunoprecipitation, site-specific mutagenesis and Western blotting, KEY RESULTS In VSMC, AngII induced Cl(-) currents was carried by the chloride ion channel ClC-3. This current was absent in VSMC from ClC-3 channel null mice. The AngII-induced Cl(-) current involved interactions between ClC-3 channels and Rho-kinase 2 (ROCK2), shown by N- or C-terminal truncation of ClC-3 protein, ROCK2 siRNA and co-immunoprecipitation assays. Phosphorylation of ClC-3 channels at Thr(532) by ROCK2 was critical for AngII-induced Cl(-) current and VSMC migration. The ClC-3 T532D mutant (mutation of Thr(532) to aspartate), mimicking phosphorylated ClC-3 protein, significantly potentiated AngII-induced Cl(-) current and VSMC migration, while ClC-3 T532A (mutation of Thr(532) to alanine) had the opposite effects. AngII-induced cell migration was markedly decreased in VSMC from ClC-3 channel null mice that was insensitive to Y27632, an inhibitor of ROCK2. In addition, AngII-induced cerebrovascular remodelling was decreased in ClC-3 null mice, possibly by the ROCK2 pathway. CONCLUSIONS AND IMPLICATIONS ClC-3 protein phosphorylation at Thr(532) by ROCK2 is required for AngII-induced Cl(-) current and VSMC migration that are involved in AngII-induced vascular remodelling in hypertension.
Collapse
Affiliation(s)
- Ming-Ming Ma
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Cai-Xia Lin
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Can-Zhao Liu
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Min Gao
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Lu Sun
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Yong-Bo Tang
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Jia-Guo Zhou
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Guan-Lei Wang
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Yong-Yuan Guan
- Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| |
Collapse
|
3
|
Bulley S, Jaggar JH. Cl⁻ channels in smooth muscle cells. Pflugers Arch 2014; 466:861-72. [PMID: 24077695 DOI: 10.1007/s00424-013-1357-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 09/09/2013] [Accepted: 09/09/2013] [Indexed: 10/26/2022]
Abstract
In smooth muscle cells (SMCs), the intracellular chloride ion (Cl−) concentration is high due to accumulation by Cl−/HCO3− exchange and Na+–K+–Cl− cotransportation. The equilibrium potential for Cl− (ECl) is more positive than physiological membrane potentials (Em), with Cl− efflux inducing membrane depolarization. Early studies used electrophysiology and nonspecific antagonists to study the physiological relevance of Cl− channels in SMCs. More recent reports have incorporated molecular biological approaches to identify and determine the functional significance of several different Cl− channels. Both "classic" and cGMP-dependent calcium (Ca2+)-activated (ClCa) channels and volume-sensitive Cl− channels are present, with TMEM16A/ANO1, bestrophins, and ClC-3, respectively, proposed as molecular candidates for these channels. The cystic fibrosis transmembrane conductance regulator (CFTR) has also been described in SMCs. This review will focus on discussing recent progress made in identifying each of these Cl− channels in SMCs, their physiological functions, and contribution to diseases that modify contraction, apoptosis, and cell proliferation.
Collapse
|