Stimulation of Na+/H+ Exchanger Isoform 1 Promotes Microglial Migration

Abstract

Regulation of microglial migration is not well understood. In this study, we proposed that Na+/H+ exchanger isoform 1 (NHE-1) is important in microglial migration. NHE-1 protein was co-localized with cytoskeletal protein ezrin in lamellipodia of microglia and maintained its more alkaline intracellular pH (pHi). Chemoattractant bradykinin (BK) stimulated microglial migration by increasing lamellipodial area and protrusion rate, but reducing lamellipodial persistence time. Interestingly, blocking NHE-1 activity with its potent inhibitor HOE 642 not only acidified microglia, abolished the BK-triggered dynamic changes of lamellipodia, but also reduced microglial motility and microchemotaxis in response to BK. In addition, NHE-1 activation resulted in intracellular Na+ loading as well as intracellular Ca2+ elevation mediated by stimulating reverse mode operation of Na+/Ca2+ exchange (NCXrev). Taken together, our study shows that NHE-1 protein is abundantly expressed in microglial lamellipodia and maintains alkaline pHi in response to BK stimulation. In addition, NHE-1 and NCXrev play a concerted role in BK-induced microglial migration via Na+ and Ca2+ signaling.

Membrane androgen receptor sensitive Na+/H+ exchanger activity in prostate cancer cells

“…1), indicating that this TAC-effect is a transient phenomenon. This transient effect may also account for the seeming paradox that TAC stimulates the sodium hydrogen exchangers which is known to participate in the machinery accomplishing cell migration [40] and yet inhibits cell migration as previously reported [7]. According to previous studies [41] [7,8].…”

Sodium-Hydrogen-Exchanger expression in human sperm and its relationship with semen parameters

“…Recent studies suggested that NHE activity and normalized pH are required in the migration of various cells. Stimulation of NHE-1 promotes microglial migration via Na + and Ca 2+ signaling [22]; increased NHE activity contributes to proliferation and migration of smooth muscle cells in the model of pulmonary arterial hypertension [23]. Of interest, the results showed that sNHE expression is positively correlated with motility parameters.…”

Upregulation of NHE1 protein expression enables glioblastoma cells to escape TMZ-mediated toxicity via increased H+extrusion, cell migration and survival

“…Colocalization of NHE1 and ezrin was analyzed using Image J software with the Colocalization Indices plugin (50). The Pearson's correlation coefficient and overlap coefficient were used as indices of the frequency of colocalization between NHE1 and ezrin as described previously (16). Pearson correlation coefficient was calculated using online statistics software (http://www.wessa.net/, Free Statistics Software, Office for Research Development and Education, version 1.1.23-r7).…”

“…The cells were excited every 20 s at 440 and 490 nm, and the emission fluorescence at 535 nm was recorded (16). The ratio of the background-corrected fluorescence emissions (F 490 /F 440 ) was calibrated using the high-K + /nigericin technique (17).…”

“…Cell lysates (0.2 mg protein) were incubated with 2 mg of mouse anti-ezrin antibody at 4°C overnight. Immunocomplexes were mixed with 20 μl protein A/G beads (50% slurry) in a Pierce spin column and incubated for 2 h. The immunocomplexes were washed and analyzed as described before (16).…”