Potassium Channels Expression On CD4⁺ And CD4⁺CD28^null T Cells In Patients With Acute Coronary Syndrome And Its Implications

Part 1 Kv1.3 Potassium Channel Expression on CD4⁺ and CD4⁺CD28^nullT Cells in Patients with Acute Coronary Syndrome and ItsImplications【Objective】To study the changes of Kv1.3 channel expression during activation onCD4⁺ and CD4⁺CD28^null T cells in peripheral blood of acute coronary syndrome(ACS)patients and the effects of Kv1.3-specific channel blocker on effectors expression ofCD4⁺ T cell after activation, further discuss the implications of Kv1.3 channel foratheromatous plaques development.【Methods】CD4⁺ T cells in all of and subsets CD4⁺CD28^null/CD4⁺CD28⁺ T cells in12 of 27 ACS patients were isolated from peripheral blood with magnetic cell sorting.The Kv1.3 currents for three types of T cells above were recorded with whole-cellpatch-clamp technique before and 72 hours after activation by purified anti-humanCD3 mAb.Upon activation, 0.1, 1, 10nmol/L of recombinant Margatoxin (rMgTX), a specific blocker of Kv1.3 channel, were added separately to CD4⁺ T cells.72 hourslater, the mRNA expressions of interferon gamma, tumor necrosis factor alpha(TNF-α), granzyme B in CD4⁺ T cells were determined by reverse transcription-PCR.【Results】After activation all peak currents of Kv1.3 channel on CD4⁺,CD4⁺CD28^null T cells were significantly enlarged, and the mean Kv1.3 channelnumbers per cell of each kind of cell aforementioned were respectively increased byaround 90%, 60% (402±88 vs.752±275, 553±328 vs.874±400 channels per cellbefore vs.after activation respectively, both P<0.05).The channels on each restingCD4⁺CD28^null T cells were about 40% more than those on each resting CD4⁺CD28⁺ Tcells(P<0.05), whereas there was no difference in channels between the bothactivated T cells(P=0.102).The mRNA expression of interferon gamma, TNF-αand granzyme B were down-regulated by all of rMgTX, and differential expressionof each mRNA existed among varied concentration of rMgTX (P<0.01, respectively).The larger dose of rMgTX, the smaller expression of each mRNA.【Conclusions】kv1.3 channels increased largely on peripheral blood CD4⁺T cellsand its subset CD4⁺CD28^null T cells after activation in ACS patients, and Kv1.3-specific channel blocker rMgTX inhibited the mRNA expression of interferongamma, TNF-αand granzyme B in CD4⁺ T cells in a dose-depend mode.Kv1.3channel on CD4⁺ T cells especially on CD4⁺CD28^null T cells, thus, may be suggestedas a potential therapeutic target for preventing atheromatous plaques fromdestablization. Part 2 IKCa1 Potassium Channel Expression on CD4⁺ andCD4⁺CD28^null T Cells in Patients with Acute Coronary Syndrome andIts Implications【Objective】To study the number changes of IKCa1 channel during activation onperipheral blood CD4⁺ T cells and its subset CD4⁺CD28^null in ACS patients and theeffects of IKCa1-specific channel blocker on effectors expression of activated CD4⁺T cell, further discuss the implications of IKCa1 channel for atheromatous plaques.【Methods】CD4+ T cells in all of and CD4⁺CD28^null T cells in 12 of 24 ACSpatients were isolated from peripheral blood through magnetic cell sorting.Thewhole-cell IKCa1 currents of T cells above were recorded with patch-clamptechnique before and 3 days after activation by purified anti-human CD3 mAb.0.2, 1,5μmol/L of TRAM-34, a specific blocker of IKCa1 channel, were added separatelyto 3-day pre-activated CD4⁺T cells, and 3 days' activation followed.The mRNAexpressions of interferon gamma, TNF-α, granzyme B in CD4⁺ T cells were detectedby reverse transcription-PCR.【Results】IKCa1 channels on each activated CD4⁺ and CD4⁺CD28^null T cell wererespectively proximately 9 and 8 times higher than those on each resting CD4⁺ andCD4⁺CD28^null T cell (439±161 vs.45±18, 497±174 vs.56±16 channels per cell aftervs.before activation respectively, both P<0.05).Both activated T cells had up totriple channel density, compared to their resting ones (both P<0.05).The numbersand density of IKCa1 channel were parallel between both T cells regardless ofactivation.The mRNA expression of interferon gamma, TNF-α, and granzyme Bwere down-regulated by all dose of TRAM-34, and differential expression of eachmRNA existed among varied dose of TRAM-34(P<0.01, respectively).The largerdose of rMgTX, the smaller expression of each mRNA.【Conclusions】IKCa1 channel numbers and density increased significantly on peripheral blood CD4⁺ and CD4⁺CD28^null T cells after activation in ACS patients,and IKCa1-specific channel blocker TRAM-34 inhibited the mRNA expressions ofinterferon gamma, TNF-α, and granzyme B in activated CD4⁺ T cells in adose-depend pattern.It may be indicated that IKCa1 channel on activated CD4⁺ Tcells play an important role in atherosclerosis, and that IKCa1 channel blockers haveuse in therapeutic manipulation of atherosclerosis.