Involvement of voltage gated proton channel (hv) inhibition, in leukemic Jurkat T cells apoptosis

ASUAJE, A; MARTÍN, P; ORLOWSKY, A; SMALDINI, P; AIELLO, A; GONZÁLEZ, C; DOCENA, G; MILESI, V

Capital Federal

Congreso; IV Congress of Latin American Society for Immunodeficiencies (LASID), LXIII Argentinean Immunology Society Meeting, II French-Argentinean Immunology Meeting; 2015

Sociedad Argentiona de Inmunologia, Latin American Society for Immunodeficiencies

Title: INVOLVMENT OF VOLTAGE GATED PROTON CHANNEL(Hv) INHIBITION, IN LEUKEMIC JURKAT T CELLS APOPTOSIS Authors:  1Asuaje  A, - 1Martín, P,  1Smaldini, P - 2Orlowski,A. ?2 Aiello, A. ? 3González León, C. ? 1Docena,G. ? 1Milesi, V.1 IIFP  CONICET ? UNLP; Argentina 2 CIC CONICET-UNLP; Argentina3 CINV ?UNV, Chile. AbstractBackground The human voltage gated protonchannel (hHv) is a highly selective ion channel present in almost every immune systemcell capable of mediate fast H+ ions extrusion. Its activity is markedlyregulated by the voltage membrane and the pHo/pHi ratio, and it is blocked byZn2+ ions. In leukemic Jurkat T cells (as in many others) apoptosis mechanismswhere described to be dependent of intracellular acidification, so, hHvinhibition could be relevant to induce cell acidification and apoptosis. Methods: hHv currents where recorded bypatch-clamp technique in its whole-cell configuration. pHi was measured bymeans of BECEF ratiometric fluorometry in cells suspension and apoptosis wasanalysed by flow cytometry using propidium iodide(PI)/Annexin V-FITC(AnnexinV+/PI- were considered as cells undergoing early apoptosis). Cells wereincubated during 9 hs with or without Zn+2 (1mM) in three experimentalconditions: resting stimulated with propionic acid and in presence of NAC (aROS scavenger). Results: The presence of H+ currentswas electrophysiologically confirmed and they could be completely blocked by 250µM of free Zn2+.  Then, wefound that extracellular Zn2+ (1mM) induced intracellular acidification in JurkatT cells in resting conditions and prevents pHi recovery after acid load with propionicacid. Finally, the presence of Zn+2induced a significant increase in the frequency of AnnexinV+ cells (40,7%±10,3 Zn+2 vs 13,2%±2,7 controlconditions), which was not reverted using ROS scavengers. Conclusions Our findings suggest that hHv channels might bean important but unexplored player in apoptosis control mechanisms of the leukemicJurkat T cells .