(768.7) Pulmonary endothelial cells from different vascular compartments exhibit unique recovery from acidification and Na+/H+ exchanger isoform expression

Poster Board Number: E588

Sarah Sayner (University of South Alabama), Chug-Sik Choi (University of South Alabama), Dylan Adams (University of South Alabama)

Sodium-hydrogen exchangers (NHEs) tightly regulate intracellular pH (pHi), proliferation, migration and cell volume.  Heterogeneity exists between pulmonary endothelial cells derived from different vascular segments, yet the activity and isoform expression of NHEs between these vascular segments has not been fully examined. 

Utilizing the ammonium-prepulse and recovery from acidification technique in a buffer lacking bicarbonate, pulmonary microvascular and pulmonary artery endothelial cells exhibited a similar rate of recovery from the acid load regardless of the concentrations of the sodium transport inhibitor, amiloride; however, pulmonary artery endothelial cells required a higher dose of amiloride to inhibit sodium-dependent acid recovery compared to pulmonary microvascular endothelial cells, suggesting a unique complement of NHEs between the different endothelial cell types.  While NHE1 has been described in pulmonary endothelial cells, all NHE isoforms have not been accounted for.  To address NHE expression in endothelial cells, qPCR was performed.  Using a two-gene normalization approach, Sdha and Ywhag were identified for qPCR normalization and analysis of NHE isoforms between pulmonary microvascular and pulmonary artery endothelial cells.  NHE1 and NHE8 mRNA were equally expressed between the two cell types, but NHE5 expression was significantly higher in pulmonary microvascular and pulmonary artery endothelial cells. 

Thus, pulmonary microvascular and pulmonary artery endothelial cells exhibit unique NHE isoform expression and have a unique response to acid load revealed through recovery from cellular acidification.

Support or Funding Information

This work was support by NIH (R01 HL121513), the Center for Lung Biology Murray Bander Award, and the USA COM Intramural Grants Program to SLS and the NIH (HL66299) to the Center for Lung Biology Cell Culture Core