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Role of Hypoxia-Induced Brain Derived Neurotrophic Factor in Human Pulmonary Artery Smooth Muscle.

Hartman W, Helan M, Smelter D, Sathish V, Thompson M, Pabelick CM, Johnson B, Prakash YS - PLoS ONE (2015)

Bottom Line: Recent studies suggest that growth factors called neurotrophins, particularly brain-derived neurotrophic factor (BDNF), can influence lung structure and function, and their role in the pulmonary artery warrants further investigation.In arteries of patients with pulmonary hypertension, BDNF expression and release was higher at baseline.Accordingly, the BDNF-TrkB system could be a key player in the pathogenesis of hypoxia-induced pulmonary vascular diseases, and thus a potential target for therapy.

View Article: PubMed Central - PubMed

Affiliation: Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, 55905, United States of America.

ABSTRACT

Background: Hypoxia effects on pulmonary artery structure and function are key to diseases such as pulmonary hypertension. Recent studies suggest that growth factors called neurotrophins, particularly brain-derived neurotrophic factor (BDNF), can influence lung structure and function, and their role in the pulmonary artery warrants further investigation. In this study, we examined the effect of hypoxia on BDNF in humans, and the influence of hypoxia-enhanced BDNF expression and signaling in human pulmonary artery smooth muscle cells (PASMCs).

Methods and results: 48h of 1% hypoxia enhanced BDNF and TrkB expression, as well as release of BDNF. In arteries of patients with pulmonary hypertension, BDNF expression and release was higher at baseline. In isolated PASMCs, hypoxia-induced BDNF increased intracellular Ca2+ responses to serotonin: an effect altered by HIF1α inhibition or by neutralization of extracellular BDNF via chimeric TrkB-Fc. Enhanced BDNF/TrkB signaling increased PASMC survival and proliferation, and decreased apoptosis following hypoxia.

Conclusions: Enhanced expression and signaling of the BDNF-TrkB system in PASMCs is a potential mechanism by which hypoxia can promote changes in pulmonary artery structure and function. Accordingly, the BDNF-TrkB system could be a key player in the pathogenesis of hypoxia-induced pulmonary vascular diseases, and thus a potential target for therapy.

No MeSH data available.


Related in: MedlinePlus

Characterization of human pulmonary artery smooth muscle cells (PASMCs).(a) Representative Western blot of proteins confirming PASMC phenotype including smooth muscle myosin, smooth muscle actin, acetylcholine receptor, and transgelin. Hypoxia enhances PASMC brain derived neurotrophic factor (BDNF) secretion. (b) Western blot analysis of human pulmonary artery smooth muscle cells (PASMCs) demonstrated presence of BDNF, with increased expression following 48h of 1% hypoxia. (c) Human PASMCs secrete BDNF, and such secretion is increased with hypoxia, as demonstrated by ELISA of supernatant in PASMC cultures. (d) Representative Western analysis showed increased TrkB expression (particularly full-length; FL) in PASMCs following hypoxia. (e) Immunocytochemistry demonstrating enhanced BDNF and TrkB expression in hypoxia-exposed human PASMCs compared to normoxia (green color represents BDNF or TrkB, red color represents α-smooth muscle actin, blue color (DAPI) represents nucleus staining. Values are means ± SE (n = 5 patients without pulmonary vascular disease). *Significant difference from normoxia (p<0.05).
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pone.0129489.g001: Characterization of human pulmonary artery smooth muscle cells (PASMCs).(a) Representative Western blot of proteins confirming PASMC phenotype including smooth muscle myosin, smooth muscle actin, acetylcholine receptor, and transgelin. Hypoxia enhances PASMC brain derived neurotrophic factor (BDNF) secretion. (b) Western blot analysis of human pulmonary artery smooth muscle cells (PASMCs) demonstrated presence of BDNF, with increased expression following 48h of 1% hypoxia. (c) Human PASMCs secrete BDNF, and such secretion is increased with hypoxia, as demonstrated by ELISA of supernatant in PASMC cultures. (d) Representative Western analysis showed increased TrkB expression (particularly full-length; FL) in PASMCs following hypoxia. (e) Immunocytochemistry demonstrating enhanced BDNF and TrkB expression in hypoxia-exposed human PASMCs compared to normoxia (green color represents BDNF or TrkB, red color represents α-smooth muscle actin, blue color (DAPI) represents nucleus staining. Values are means ± SE (n = 5 patients without pulmonary vascular disease). *Significant difference from normoxia (p<0.05).

Mentions: Human PASMC were characterized by Western Blots demonstrating the presence of smooth muscle myosin, alpha smooth muscle actin, the acetylcholine receptor, and transgelin (Fig 1A). Western blot analysis of whole cell extracts of human PASMCs demonstrated the presence of BDNF with increased expression following hypoxia (Fig 1B, n = 3 patients without pulmonary vascular disease). In addition, immunohistochemistry demonstrated enhanced BDNF in hypoxia exposed PASMC compared to normoxia cells (Fig 1E). Importantly, ELISA of the supernatant from PASMCs exposed to normoxia vs. hypoxia (1% O2 which is known to induce HIF1α; see below)[8,39,40] demonstrated baseline presence of BDNF with increased secretion following hypoxia (Fig 1D; n = 7 patients without pulmonary vascular disease; p<0.05). In parallel Western blot studies, we found significantly increased full-length PASMC TrkB protein expression following hypoxia (Fig 1E; p<0.05). This increase in TrkB expression following hypoxia exposure further confirmed by immunofluorescence (Fig 1E).


Role of Hypoxia-Induced Brain Derived Neurotrophic Factor in Human Pulmonary Artery Smooth Muscle.

Hartman W, Helan M, Smelter D, Sathish V, Thompson M, Pabelick CM, Johnson B, Prakash YS - PLoS ONE (2015)

Characterization of human pulmonary artery smooth muscle cells (PASMCs).(a) Representative Western blot of proteins confirming PASMC phenotype including smooth muscle myosin, smooth muscle actin, acetylcholine receptor, and transgelin. Hypoxia enhances PASMC brain derived neurotrophic factor (BDNF) secretion. (b) Western blot analysis of human pulmonary artery smooth muscle cells (PASMCs) demonstrated presence of BDNF, with increased expression following 48h of 1% hypoxia. (c) Human PASMCs secrete BDNF, and such secretion is increased with hypoxia, as demonstrated by ELISA of supernatant in PASMC cultures. (d) Representative Western analysis showed increased TrkB expression (particularly full-length; FL) in PASMCs following hypoxia. (e) Immunocytochemistry demonstrating enhanced BDNF and TrkB expression in hypoxia-exposed human PASMCs compared to normoxia (green color represents BDNF or TrkB, red color represents α-smooth muscle actin, blue color (DAPI) represents nucleus staining. Values are means ± SE (n = 5 patients without pulmonary vascular disease). *Significant difference from normoxia (p<0.05).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4507987&req=5

pone.0129489.g001: Characterization of human pulmonary artery smooth muscle cells (PASMCs).(a) Representative Western blot of proteins confirming PASMC phenotype including smooth muscle myosin, smooth muscle actin, acetylcholine receptor, and transgelin. Hypoxia enhances PASMC brain derived neurotrophic factor (BDNF) secretion. (b) Western blot analysis of human pulmonary artery smooth muscle cells (PASMCs) demonstrated presence of BDNF, with increased expression following 48h of 1% hypoxia. (c) Human PASMCs secrete BDNF, and such secretion is increased with hypoxia, as demonstrated by ELISA of supernatant in PASMC cultures. (d) Representative Western analysis showed increased TrkB expression (particularly full-length; FL) in PASMCs following hypoxia. (e) Immunocytochemistry demonstrating enhanced BDNF and TrkB expression in hypoxia-exposed human PASMCs compared to normoxia (green color represents BDNF or TrkB, red color represents α-smooth muscle actin, blue color (DAPI) represents nucleus staining. Values are means ± SE (n = 5 patients without pulmonary vascular disease). *Significant difference from normoxia (p<0.05).
Mentions: Human PASMC were characterized by Western Blots demonstrating the presence of smooth muscle myosin, alpha smooth muscle actin, the acetylcholine receptor, and transgelin (Fig 1A). Western blot analysis of whole cell extracts of human PASMCs demonstrated the presence of BDNF with increased expression following hypoxia (Fig 1B, n = 3 patients without pulmonary vascular disease). In addition, immunohistochemistry demonstrated enhanced BDNF in hypoxia exposed PASMC compared to normoxia cells (Fig 1E). Importantly, ELISA of the supernatant from PASMCs exposed to normoxia vs. hypoxia (1% O2 which is known to induce HIF1α; see below)[8,39,40] demonstrated baseline presence of BDNF with increased secretion following hypoxia (Fig 1D; n = 7 patients without pulmonary vascular disease; p<0.05). In parallel Western blot studies, we found significantly increased full-length PASMC TrkB protein expression following hypoxia (Fig 1E; p<0.05). This increase in TrkB expression following hypoxia exposure further confirmed by immunofluorescence (Fig 1E).

Bottom Line: Recent studies suggest that growth factors called neurotrophins, particularly brain-derived neurotrophic factor (BDNF), can influence lung structure and function, and their role in the pulmonary artery warrants further investigation.In arteries of patients with pulmonary hypertension, BDNF expression and release was higher at baseline.Accordingly, the BDNF-TrkB system could be a key player in the pathogenesis of hypoxia-induced pulmonary vascular diseases, and thus a potential target for therapy.

View Article: PubMed Central - PubMed

Affiliation: Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, 55905, United States of America.

ABSTRACT

Background: Hypoxia effects on pulmonary artery structure and function are key to diseases such as pulmonary hypertension. Recent studies suggest that growth factors called neurotrophins, particularly brain-derived neurotrophic factor (BDNF), can influence lung structure and function, and their role in the pulmonary artery warrants further investigation. In this study, we examined the effect of hypoxia on BDNF in humans, and the influence of hypoxia-enhanced BDNF expression and signaling in human pulmonary artery smooth muscle cells (PASMCs).

Methods and results: 48h of 1% hypoxia enhanced BDNF and TrkB expression, as well as release of BDNF. In arteries of patients with pulmonary hypertension, BDNF expression and release was higher at baseline. In isolated PASMCs, hypoxia-induced BDNF increased intracellular Ca2+ responses to serotonin: an effect altered by HIF1α inhibition or by neutralization of extracellular BDNF via chimeric TrkB-Fc. Enhanced BDNF/TrkB signaling increased PASMC survival and proliferation, and decreased apoptosis following hypoxia.

Conclusions: Enhanced expression and signaling of the BDNF-TrkB system in PASMCs is a potential mechanism by which hypoxia can promote changes in pulmonary artery structure and function. Accordingly, the BDNF-TrkB system could be a key player in the pathogenesis of hypoxia-induced pulmonary vascular diseases, and thus a potential target for therapy.

No MeSH data available.


Related in: MedlinePlus