Characterization of the Na+/HCO3- cotransport in human neutrophils

GIAMBELLUCA MS; CIANCIO MC; ORLOWSKI A; GENDE OA; POULIOT M; AIELLO EA

CELLULAR PHYSIOLOGY AND BIOCHEMISTRY : INTERNATIONAL JOURNAL OF EXPERIMENTAL CELLULAR PHYSIOLOGY, BIOCHEMISTRY, AND PHARMACOLOGY.

KARGER

Lugar: Basel; Año: 2014 vol. 33 p. 982 - 990

1015-8987

Bicarbonate transport has crucial roles in regulating intracellular pH (pHi) in a variety of cells. The purpose of this study was to evaluate its participation in the regulation of pHi in resting and stimulated human neutrophils. We demonstrated that resting neutrophils have a bicarbonate transport mechanism that prevents acidification when the Na+/H+ exchanger is blocked by EIPA. Neutrophils acidified by an ammonium prepulse showed an EIPA-resistant recovery of pHi that was inhibited by the blocker of the anionic transporters SITS or the Na+/HCO3- cotransporter (NBC) selective inhibitor S0859, and abolished when sodium was removed from the extracellular medium. In western blot and RT-PCR analysis the expression of NBCe2 but not NBCe1 or NBCn1 was detected in neutrophils isolated membranes. Acidified neutrophils increased the EIPA-insensitive pHi recovery rate when its activity was stimulated with fMLF/cytochalasin B. This increase in the removal of acid equivalents was insensitive to the blockade of the NADPH oxidase with DPI. It is concluded that neutrophils have an NBC that regulates basal pHi and is modulated by chemotactic agents.