Abstract:
Endothelial cells (EC) have dynamic properties and high plasticity in response to
microenvironmental change. A proinflammatory cytokine such as tumor necrotizing factor-α (TNF-α) can
induce EC phenotype shift to osteoinduction properties by releasing a potent osteogenic cytokine, namely
bone morphogenetic protein 2 (BMP2). Normally BMP2 acts as an osteoblast stimulating factor in bone and
cartilage tissue. BMP2 activation in vascular tissue will invite osteoblast recruitment and mineralization and
generated pathological vascular stiffening and calcification. Recently, endoplasmic reticulum stress (ERS)
has been emerging as a new target therapy in many vascular diseases such as vascular stiffening and
calcification. Some short-chain fatty acid like 4-phenyl butyric acid has been shown had anti-ERS properties.
However, the role of 4-phenyl butyric acid in BMP2 inhibition in endothelial cells is still poorly understood.
Hence, we investigated the role of 4-phenyl butyric acid in inflammation-induced BMP2 expression in human
vein derived endothelial cells. Endothelial cells obtained from a baby born umbilical vein were cultured and
pre-treated with TNF-α (5 ng/ml) as inflammation precondition. Multiple doses of 4-phenyl butyrate acid (4-
PBA) 1 nM/mL, 2 nM /mL, and 3 nM /m were used as ERS inhibitors. The expression of two ERS biomarkers,
glucose-related protein-8 (GRP78) and activating transcription factor-6 (ATF6), were measured. Statistical
analysis was done using one-way ANOVA and Kruskal Wallis tests, and P<0.01 considered as significant. 4-
PBA decrease luminal BMP2 at dose one nM/L, GRP78 at dose 1 nM/L, and translocated ATF6 expression at
dose 1 nM/L in endothelial culture dose-dependently. Short-chain fatty acid 4-phenylbutyrate acid decreases
luminal ERS marker GRP78 and translocated ATF6 expression in endothelial culture. ERS has a role in
osteoinductive phenotype shifting in inflammation endothelial cells, which was the novelty of this research.
Further research needs to elucidate ERS inhibition in in vivo experiment
© 2021 Tehran University of Medical Sciences. All rights reserved.
Acta Med Iran 2021;59(2):79-85.
Keywords: Bone morphogenetic protein-2; Endoplasmic reticulum stress; Endothelial cells; Small chain
fatty acid; Tumor necrosis factor-α
