Pneumologie 2015; 69 - A20
DOI: 10.1055/s-0035-1556612

Regulation of angiogenesis-related genes in human pulmonary microvascular endothelial cells by alpha1-antitrypsin

S Wrenger 1, N Aggarwal 1, E Frenzel 1, S Immenschuh 2, T Welte 1, S Janciauskiene 1
  • 1Hannover Medical School, Department of Respiratory Medicine
  • 2Hannover Medical School, Department of Transfusion Medicine

Introduction:

Alpha1-antitrypsin (A1AT) is an anti-protease that has broad anti-inflammatory and immunoregulatory effects and emerges as a major protective factor against chronic obstructive lung disease (COPD). Evidence exists that COPD is associated with structural and functional changes in the lung circulation. Altered angiogenesis and microvascular remodeling might be an initiating event promoting COPD. Thus, question arose if A1AT influences angiogenesis-related genes in human pulmonary microvascular endothelial cells (HPMVEC).

Methods:

HPMVEC were treated with 1 mg/ml human plasma-derived A1AT (Prolastin®, Grifols) alone or in combination with 1 µg/ml LPS or 50 ng/ml IL-8. After incubation cells were harvested for Western blot or for RNA preparation (RNeasy MiniKit, Qiagen) and subsequent gene expression analysis on angiogenesis arrays (SABiosciences Qiagen) or by TaqMan Gene Expression Assay (Life Technologies). Culture supernatants were analyzed for angptl4 protein levels using DuoSet ELISA sets (R&D Systems).

Results:

Angiogenesis array shows that 8h treatment with A1AT alone or in combination with LPS or IL-8 affects expression of certain angiogenesis-related genes of HPMVEC. Specifically, angiopoietin-like protein 4 (angptl4) mRNA was significantly increased in A1AT-treated cells independent of stimulation. A1AT up-regulates expression and release of angplt4 in a concentration- and time-dependent manner. A1AT-induced angptl4 expression and release was clearly diminished in cells pre-treated for 30 min with a specific inhibitor of ERK1/2 activation (UO126) or with a selective PPARγ antagonist (GW9662). This suggests that PPARγ is a critical mediator in A1AT-driven angptl4 induction. LPS or IL-8 did not interfere with A1AT-induced angptl4 expression and release indicating that induction of angptl4 by A1AT is independent of proinflammatory conditions.

Discussion:

Angptl4 is known to influence angiogenesis and vascular integrity, to support wound healing and to prevent progressive inflammation and cell death. Our data suggest that A1AT could resolve inflammation and suppress development of COPD via induction of angplt4 in HPMVEC.

*Presenting author