TY - JOUR
T1 - BDNF secretion by human pulmonary artery endothelial cells in response to hypoxia
AU - Helan, Martin
AU - Aravamudan, Bharathi
AU - Hartman, William R.
AU - Thompson, Michael A.
AU - Johnson, Bruce D.
AU - Pabelick, Christina M.
AU - Prakash, Y. S.
N1 - Funding Information:
Martin Helan, M.D. was supported by the European Regional Development Fund — Project FNUSA-ICRC (No. CZ.1.05/1.1.00/02.0123) and the ICRC Human Bridge — Support of Study Stays of Czech Researchers Abroad: Young Talent Incubator (reg. n. CZ.1.07/2.3.00/20.0022), which is financed by the European Social Fund and the state budget of the Czech Republic through The Education for Competitiveness Operational Programme . Additional support is given by the Foundation for Anesthesia Education and Research (FAER; Hartman), the American Heart Association (Hartman) and the Loretta and Roger Nelson Career Development Award (Hartman), the Flight Attendants Medical Research Institute (FAMRI; Aravamudan) the Mayo Clinic CTSA (NCRR 1 UL1 RR024150), the National Science Foundation (BDJ, B-179-M), and the National Institutes of Health grants R01 HL088029 & HL056470 (YSP).
PY - 2014/3
Y1 - 2014/3
N2 - Within human pulmonary artery, neurotrophin growth factors [NTs; e.g. brain-derived neurotrophic factor (BDNF)] and their high-affinity receptors (tropomyosin-related kinase; Trk) and low-affinity receptors p75 neurotrophin receptor (p75NTR) have been reported, but their functional role is incompletely understood. We tested the hypothesis that BDNF is produced by human pulmonary artery endothelial cells (PAECs). In the context of hypoxia as a risk factor for pulmonary hypertension, we examined the effect of hypoxia on BDNF secretion and consequent autocrine effects on pulmonary endothelium. Initial ELISA analysis of circulating BDNF in 30 healthy human volunteers showed that 72h exposure to high altitude (~11,000ft, alveolar PO2=100mmHg) results in higher BDNF compared to samples taken at sea level. Separately, in human PAECs exposed for 24h to normoxia vs. hypoxia (1-3% O2), ELISA of extracellular media showed increased BDNF levels. Furthermore, quantitative PCR of PAECs showed 3-fold enhancement of BDNF gene transcription with hypoxia. In PAECs, BDNF induced NO production (measured using an NO-sensitive fluorescent dye DAF2-DA) that was significantly higher under hypoxic conditions, an effect also noted with the TrkB agonist 7,8-DHF. Importantly, hypoxia-induced NO was blunted by neutralization of secreted BDNF using the chimeric TrkB-Fc. Both hypoxia and BDNF increased iNOS (but not eNOS) mRNA expression. In accordance, BDNF enhancement of NO in hypoxia was not blunted by 50nM l-NAME (eNOS inhibition) but substantially lower with 100μM l-NAME (eNOS and iNOS inhibition). Hypoxia and BDNF also induced expression of hypoxia inducible factor 1 alpha (HIF-1α), a subunit of the transcription factor HIF-1, and pharmacological inhibition of HIF-1 diminished hypoxia effects on BDNF expression and secretion, and NO production. These results indicate that human PAECs express and secrete BDNF in response to hypoxia via a HIF-1-regulated pathway.
AB - Within human pulmonary artery, neurotrophin growth factors [NTs; e.g. brain-derived neurotrophic factor (BDNF)] and their high-affinity receptors (tropomyosin-related kinase; Trk) and low-affinity receptors p75 neurotrophin receptor (p75NTR) have been reported, but their functional role is incompletely understood. We tested the hypothesis that BDNF is produced by human pulmonary artery endothelial cells (PAECs). In the context of hypoxia as a risk factor for pulmonary hypertension, we examined the effect of hypoxia on BDNF secretion and consequent autocrine effects on pulmonary endothelium. Initial ELISA analysis of circulating BDNF in 30 healthy human volunteers showed that 72h exposure to high altitude (~11,000ft, alveolar PO2=100mmHg) results in higher BDNF compared to samples taken at sea level. Separately, in human PAECs exposed for 24h to normoxia vs. hypoxia (1-3% O2), ELISA of extracellular media showed increased BDNF levels. Furthermore, quantitative PCR of PAECs showed 3-fold enhancement of BDNF gene transcription with hypoxia. In PAECs, BDNF induced NO production (measured using an NO-sensitive fluorescent dye DAF2-DA) that was significantly higher under hypoxic conditions, an effect also noted with the TrkB agonist 7,8-DHF. Importantly, hypoxia-induced NO was blunted by neutralization of secreted BDNF using the chimeric TrkB-Fc. Both hypoxia and BDNF increased iNOS (but not eNOS) mRNA expression. In accordance, BDNF enhancement of NO in hypoxia was not blunted by 50nM l-NAME (eNOS inhibition) but substantially lower with 100μM l-NAME (eNOS and iNOS inhibition). Hypoxia and BDNF also induced expression of hypoxia inducible factor 1 alpha (HIF-1α), a subunit of the transcription factor HIF-1, and pharmacological inhibition of HIF-1 diminished hypoxia effects on BDNF expression and secretion, and NO production. These results indicate that human PAECs express and secrete BDNF in response to hypoxia via a HIF-1-regulated pathway.
KW - ENOS
KW - Hypoxia inducible factor 1
KW - INOS
KW - Neurotrophin
KW - Nitric oxide
KW - Tropomyosin related kinase
UR - http://www.scopus.com/inward/record.url?scp=84894279068&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84894279068&partnerID=8YFLogxK
U2 - 10.1016/j.yjmcc.2014.01.006
DO - 10.1016/j.yjmcc.2014.01.006
M3 - Article
C2 - 24462831
AN - SCOPUS:84894279068
SN - 0022-2828
VL - 68
SP - 89
EP - 97
JO - Journal of Molecular and Cellular Cardiology
JF - Journal of Molecular and Cellular Cardiology
ER -