Lack of effect of transmembrane gradient of magnesium and sodium on regulation of cytosolic free magnesium concentration in rat lymphocytes

Sasaki, Nobuo; Oshima, Tetsuya; Matsuura, Hideo; Yoshimura, M; Yashiki, Mikio; Higashi, Yukihito; Ishioka, Norio; Nakano, Yukiko; Kojima, Reiji; Kambe, Masayuki; Kajiyama, Goro

doi:10.1016/s0005-2736(97)00095-3

Cited by 8 publications

(6 citation statements)

References 18 publications

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“…Our control values conform with those reported by others for lymphocytes obtained from rodents on a normal diet (59). Factors that could have contributed to this decrease in [Mg 2ϩ ] i were considered.…”

Section: Discussionsupporting

confidence: 90%

Aldosteronism: an immunostimulatory state precedes proinflammatory/fibrogenic cardiac phenotype

Gerling

Sun

Ahokas

et al. 2003

American Journal of Physiology-Heart and Circulatory Physiology

106

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ϩ intake) elevations in circulating aldosterone (ALDO), termed aldosteronism, are associated with remodeling of intramural arteries of the right and left heart. Lesions appear at week 4 of treatment with ALDO and 1% dietary NaCl in uninephrectomized rats (ALDOST) and include invading monocytes, macrophages and lymphocytes with intracellular evidence of oxidative and nitrosative stress, myofibroblasts, and perivascular fibrosis. In this study, we tested the hypothesis that an immunostimulatory state with activated circulating peripheral blood mononuclear cells (PBMCs) precedes this proinflammatory and profibrogenic cardiac phenotype and is initiated by reduction in the cytosolic free Mg 2ϩ concentration ([Mg 2ϩ ]i). At 1 and 4 wk of ALDOST (preclinical and clinical stages, respectively), we monitored serum Mg 2ϩ , PBMC [Mg 2ϩ ]i and cytosolic free [Ca 2ϩ ] (via fluorimetry), and expressed genes (via microchip array) as well as markers of oxidative and nitrosative stress in plasma [␣ 1 -antiproteinase activity (␣ 1 -AP)] and cardiac tissue (immunohistochemical detection of gp91 phox subunit of NADPH oxidase and 3-nitrotyrosine). Age-and gender-matched unoperated and untreated (UO) rats and uninephrectomized salt-treated (UN) rats served as controls. Serum [Mg 2ϩ ] was unchanged by ALDOST. In contrast with UO and UN, [Mg 2ϩ ]i and plasma ␣1-AP were each reduced (P Ͻ 0.05) at weeks 1 and 4. The decline in PBMC [Mg 2ϩ ]i was accompanied by Ca 2ϩ loading. Differential (twofold and higher) expression (up-and downregulation) in PBMC transcriptomes was present at week 1 and progressed at week 4. Involved were genes for the ␣ 1-isoform of Na ϩ -K ϩ -ATPase, the ATPdependent Ca 2ϩ pump, antioxidant reserves, inducible nitric oxide synthase, and PBMC activation with autoimmune responses. Expression of 3-nitrotyrosine and activation of gp91 phox were seen in inflammatory cells that invaded intramural arteries. Thus early in aldosteronism (preclinical stage), an immunostimulatory state featuring activated circulating PBMCs with reduced ionized [Mg 2ϩ ]i and oxidative and nitrosative stress precedes and may even predispose to coronary vascular lesions that first appear at week 4. peripheral blood mononuclear cells; ionized magnesium; oxidative and nitrosative stress; transcriptome; pathology IN BOTH HUMANS AND RATS and whether derived from endogenous or exogenous sources, chronic inappropriate (relative to dietary Na ϩ intake) elevations in circulating aldosterone (ALDO) are associated with structural remodeling of intramural arteries of the right and left heart and systemic organs (9,14,15,27,39,45,52,53,63,66,75). Coronary vascular lesions in uninephrectomized rats first appear at 4 wk of ALDO-andsalt treatment (ALDOST) and involve progressively more vascular sites with continued treatment (64). Lesions consist of circulating monocytes, macrophages and lymphocytes that have invaded the perivascular space; fibroblastlike cells or myofibroblasts that express fibrillar type I and III collagens; and ultimately a pe...

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Section: Discussionsupporting

confidence: 90%

Aldosteronism: an immunostimulatory state precedes proinflammatory/fibrogenic cardiac phenotype

Gerling

Sun

Ahokas

et al. 2003

American Journal of Physiology-Heart and Circulatory Physiology

106

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“…[Mg 2ϩ ] i (18) and that, in contrast to REC, most cells have a low membrane permeability to Mg 2ϩ (17,31,37,45), Mg 2ϩ loading is a prerequisite for efflux activation (37,44,46). As in other studies (17,46), loading of REC with 6 mM Mg 2ϩ results in a comparatively small [Mg 2ϩ ] i increase of ϳ370 M, indicating effective intracellular Mg 2ϩ buffering.…”

Section: Effect Of Changing the [Namentioning

confidence: 83%

Characterization of the Na⁺-dependent Mg²⁺transport in sheep ruminal epithelial cells

Schweigel¹,

Park²,

Etschmann³

et al. 2006

American Journal of Physiology-Gastrointestinal and Liver Physi

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This study examines the routes by which Mg 2ϩ leaves cultured ovine ruminal epithelial cells (REC). Mg 2ϩ -loaded (6 mM) REC were incubated in completely Mg 2ϩ -free solutions with varying Na ϩ concentrations, and the Mg 2ϩ extrusion rate was calculated from the increase of the Mg 2ϩ concentration in the incubation medium determined with the aid of the fluorescent probe mag-fura 2 (Na ϩ salt). In other experiments, REC were also studied for the intracellular free Mg 2ϩ concentration ([Mg 2ϩ ]i; using magfura 2), the intracellular Na ϩ concentration (using Na ϩ -binding benzofuran isophthalate), the intracellular cAMP concentration ([cAMP]

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“…In contrast to other cell systems [30,31], REC are known to have a high basal Mg influx capability [21]. For this reason, there was no need to load the cells with Mg by using the ionophore A 23187 as in our previous study [5].…”

Section: [Mg 2+ ] I Change In Differently Pre-incubated Recmentioning

confidence: 88%

Rumen epithelial cells adapt magnesium transport to high and low extracellular magnesium conditions

Schweigel

Kuzinski²,

Deiner³

et al. 2009

Magnesium Research

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A protein of~70-kDa was identified as a candidate Na + /Mg 2+ exchanger in rumen epithelial cells (REC). Melastatin-related Transient Receptor Potential 7 (TRPM7) and Magnesium Transporter 1 (MagT1) transcripts and, from them, encoded proteins were also detected. The regulation of these Mg transport pathways by extracellular [Mg] changes was the main focus of this study. Therefore, a 24-h pre-incubation of ovine REC in control (1.2 mM), low (0.12 mM)-Mg, and high (5 mM)-Mg medium was performed. Na + /Mg 2+ exchangers, TRPM7 and MagT1 abundance and activity were investigated by Western blot analysis, flow cytometry, immunocytochemistry and fluorescence spectroscopic measurements of [Mg 2+ ] i changes. Inhibitors were employed to differentiate Na + /Mg 2+ exchanger-mediated (imipramine) and channel-mediated (cobalt(III)hexaammine, nitrendipine) Mg transport. Basal [Mg 2+ ] i (0.40 ± 0.02 mM) was not influenced by pre-incubation in low-or high-Mg medium. However, compared with control REC (4.1 ± 0.7 μM/min), such cells showed reduced (2.8 ± 0.6 μM/min) or elevated (6.4 ± 0.9 μM/min) Mg extrusion rates that correlated with a decreased (25%) and increased (38%) expression of the putative Na + /Mg 2+ exchanger protein, respectively. Low-and high-Mg pre-incubated REC were both characterized by an increased (30-40%) influx capacity. In low-Mg REC, the latter resulted mainly from a strong activation of the TRPM7-related transport component. The data thus clearly demonstrate the intrinsic regulation of REC transmembrane Mg transport.

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Lack of effect of transmembrane gradient of magnesium and sodium on regulation of cytosolic free magnesium concentration in rat lymphocytes

Cited by 8 publications

References 18 publications

Aldosteronism: an immunostimulatory state precedes proinflammatory/fibrogenic cardiac phenotype

Aldosteronism: an immunostimulatory state precedes proinflammatory/fibrogenic cardiac phenotype

Characterization of the Na⁺-dependent Mg²⁺transport in sheep ruminal epithelial cells

Rumen epithelial cells adapt magnesium transport to high and low extracellular magnesium conditions

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Lack of effect of transmembrane gradient of magnesium and sodium on regulation of cytosolic free magnesium concentration in rat lymphocytes

Cited by 8 publications

References 18 publications

Aldosteronism: an immunostimulatory state precedes proinflammatory/fibrogenic cardiac phenotype

Aldosteronism: an immunostimulatory state precedes proinflammatory/fibrogenic cardiac phenotype

Characterization of the Na+-dependent Mg2+transport in sheep ruminal epithelial cells

Rumen epithelial cells adapt magnesium transport to high and low extracellular magnesium conditions

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Product

Resources

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Characterization of the Na⁺-dependent Mg²⁺transport in sheep ruminal epithelial cells