TAGLN, a canonical marker of smooth muscle cells, is present in endothelial cells and involved in angiogenesis

Elongation of vascular endothelial cells (ECs) is an important process of angiogenesis. However, the molecular mechanisms remain unknown. An actin cross-linking protein TAGLN (Transgelin, SM22 or SM22alpha) is abundantly expressed in smooth muscle cells (SMCs) and widely used as its canonical marker. In the course of studies using embryonic stem cells (ESCs) carrying an Tagln promoter-driven fluorescence marker, we noticed the activation of Tagln promoter in EC elongation. Tagln promoter activation co-occurred with EC elongation by vascular endothelial growth factor (VEGF). Inhibition of PI3K-Akt and mTORC1 also induced EC elongation and Tagln promoter activation. Human umbilical vein endothelial cells (HUVECs) elongated, activated TAGLN promoter and increased TAGLN transcripts in angiogenesis model. Genetic disruption of TAGLN augmented angiogenic behaviors of HUVECs, as did the disruption of TAGLN2 and TAGLN3 genes. Tagln expression was found in ECs in mouse embryos. Our results identify TAGLN as a novel putative regulator of angiogenesis whose expression is activated in elongating ECs. This finding provides insight into the cytoskeletal regulation of EC elongation and an improved understanding of the molecular mechanisms underlying the regulation of angiogenesis.

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IL-8 reduces VCAM-1 secretion of smooth muscle cells by increasing p-ERK expression when 3-D co-cultured with vascular endothelial cells

Clinical & Investigative Medicine ◽

10.25011/cim.v34i3.15186 ◽

2011 ◽

Vol 34 (3) ◽

pp. 138 ◽

Cited By ~ 5

Author(s):

Zhi Zhang ◽

Guang Chu ◽

Hong-Xian Wu ◽

Ni Zou ◽

Bao-Gui Sun ◽

...

Keyword(s):

Endothelial Cells ◽

Smooth Muscle ◽

Smooth Muscle Cells ◽

Type I Collagen ◽

Vascular Endothelial Cells ◽

Umbilical Vein ◽

Muscle Cells ◽

Type I ◽

Vascular Endothelial ◽

Culture Model

Objective: The goal of this study was to investigate the crosstalk between vascular endothelial cells (ECs) and smooth muscle cells (SMCs) using a three-dimensional (3-D) co-culture model. In addition, the role of IL-8 in this crosstalk was investigated. Methods: A 3-D co-culture model was constructed using a Transwell chamber system and type I collagen gel. Human umbilical artery smooth muscle cells (HUASMCs) were suspended in the gel and added to the upper compartment of the Transwell. Human umbilical vein endothelial cells (HUVECs) were then grown on the surface of the gel. The growth of HUASMCs was tested with a CFDA SE cell proliferation kit. IL-8 and other bioactive substances were investigated by ELISA and real-time PCR. The alteration of p-ERK expression related to the change in IL-8 levels was also examined by Western blot analysis. Results: The proliferation rate of HUASMCs in the 3-D co-culture model was 0.679 ± 0.057. Secretion and transcription of VEGF, t-PA, NO and VCAM-1 in the 3-D co-culture model were different than in single (2-D) culture. When 3-D co-cultured, IL-8 released by HUVECs was significantly increased (2.35 ± 0.16 fold) (P﹤0.05) and the expression of VCAM-1 from HUASMCs was reduced accordingly (0.55±0.09 fold). In addition, increasing or decreasing the level of IL-8 changed the level of p-ERK and VCAM-1 expression. The reduction of VCAM-1, resulting from increased IL-8, could be blocked by the MEK inhibitor, PD98059. Conclusion: Crosstalk between HUVECs and HUASMCs occurred and was probably mediated by IL-8 in this 3-D co-culture model.

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