Live monitoring of small vessels during development and disease using the flt-1 promoter element

Abstract

Vessel formation is of critical importance for organ function in the normal and diseased state. In particular, the labeling and quantitation of small vessels prove to be technically challenging using current approaches. We have, therefore, established a transgenic embryonic stem (ES) cell line and a transgenic mouse model where the vascular endothelial growth factor receptor VEGFR-1 (flt-1) promoter drives the expression of the live reporter eGFP. Fluorescence microscopy and immunostainings revealed endothelial-specific eGFP labeling of vascular networks. The expression pattern recapitulates that of the endogenous flt-1 gene, because small and large vessels are labeled by eGFP during embryonic development; after birth, the expression becomes more restricted to small vessels. We have explored this in the cardiovascular system more in detail and found that all small vessels and capillaries within the heart are strongly eGFP+. In addition, myocardial injuries have been induced in transgenic mice and prominent vascular remodeling, and an increase in endothelial cell area within the peri-infarct area could be observed underscoring the utility of this mouse model. Thus, the transgenic flt-1/eGFP models are powerful tools to investigate and quantify vascularization in vivo and to probe the effect of different compounds on vessel formation in vitro.

Thiazine Red+ platelet inclusions in Cerebral Blood Vessels are first signs in an Alzheimer’s Disease mouse model

“…The green fluorescent protein (GFP) vessel mice have been fully characterized by Herz et al . 14 . The GFP is under control of the FLT1 (FMS-like tyrosine kinase 1) promotor and these mice express GFP in nearly all vessels (GFP_FLT1 mice).…”

“…In order to study the development of Aβ plaques and the association with brain vessels especially the formation of CAA, we aim to crossbreed an Alzheimer mouse model (overexpressing APP with the Swedish-Dutch-Iowa mutations; APP_SweDI13) with GFP_FLT1 mice displaying green fluorescent protein (GFP + ) in the endothelium of vessels14. This model may allow us to follow up Aβ plaques in close association with vessels.…”

RGD peptides induce relaxation of pulmonary arteries and airwaysviaβ3‐integrins

“…RT‐PCR was performed as previously reported (18, 19). After homogenization with the TissueLyser LT (Qiagen, Hilden, Germany), total RNA was isolated from PAs and TRs by the RNeasy microkit (Qiagen).…”

Bacteriophage-Derived Vectors for Targeted Cancer Gene Therapy

“…In addition, the promoters of genes encoding Flt-1, vascular endothelial growth factor receptor 1, and human preproendothelin-1 have also been used in gene therapy vector systems and proved efficient to drive transgene expression in the vasculature of tumors and metastases [ 16 ]. While the usage of these promoters in targeted cancer gene therapy proved efficient to deliver transgene expression in the tumor vasculature, they still have limitations as some of these promoters were shown to be active in small vessels and upregulated in injured vessels as well [ 31 ].…”