C57BL/6-Tg(Tagln-Tfpi)1661Rdsi/J

Stock number: 017602
Research areas: Cardiovascular Research, Developmental Biology Research, Immunology, Inflammation and Autoimmunity Research, Metabolism Research, Research Tools

Description

These SM22α-mTFPI transgenic mice have vascular smooth muscle cell-directed overexpression of a mouse tissue factor pathway inhibitor cDNA sequence encoding the TFPIα isoform (TFPIα is the predominant TFPI protein isoform in humans). These mice may be useful in studying the role of vascular TFPI expression in intravascular thrombosis, the tissue factor pathway in vascular disease, coagulation, innate immunity, angiogenesis, and lipid metabolism.

Detailed description

Mice homozygous for the SM22α-mTFPI transgene are viable and fertile, with the mouse SM22α promoter fragment directing expression of a mouse tissue factor pathway inhibitor cDNA sequence encoding the TFPIα isoform (TFPIα is the predominant TFPI protein isoform in humans).

As such, SM22α-mTFPI transgenic mice have vascular smooth muscle cell-directed overexpression of TFPI in a tissue-specific and local manner. Specifically, homozygous SM22α-mTFPI transgenic mice from founder line 1661 have transgene mRNA levels approximately 4-fold higher than endogenous TFPI mRNA in aortic homogenates. Similarly, TFPI activity of carotid artery homogenates from homozygous transgenic mice showed 2- to 3-fold increase compared to wildtype mice. SM22α-mTFPI mice have increased circulating levels of TFPI antigen, but no increase in TFPI activity in plasma, compared to wildtype mice. Transgenic TFPI expression is also observed in smooth muscle-rich tissues such as lung, heart and kidney. Local TFPI overexpression does not affect hemostasis, but significantly attenuates ferric chloride-induced arterial thrombosis.

When SM22α-TFPI transgenic mice are made deficient of endogenous TFPI expression (by breeding with Tfpi-knockout mice), the resulting double mutant homozygous mice demonstrate that transgenic SM22α-directed TFPI overexpression is not sufficient to rescue TFPI-null embryonic lethality.

Additionally, SM22α-TFPI mice fed a high-fat diet demonstrate lower cholesterol levels than wildtype mice. Similarly, when SM22α-TFPI transgenic mice are made deficient of endogenous apolipoprotein E (by breeding with apoE-knockout mice) for high-fat diet studies, SM22α-directed TFPI overexpression attenuates aortic plaque burden and results in lower plasma cholesterol levels compared to apoE-/- mice.

Development

The SM22α-mTFPI transgene was designed with the 441 bp mouse SM22α (transgelin; Tagln) promoter fragment upstream of a mouse tissue factor pathway inhibitor (Tfpi) cDNA sequence encoding the TFPIα isoform (TFPIα is the predominant TFPI protein isoform in humans).

The transgene was microinjected into fertilized C57BL/6 eggs. The resulting transgenic offspring were bred to C57BL/6J mice to establish founder mice. Mice with the highest expression of transgenic TFPI mRNA were identified (founder line 1661) and subsequently bred together. The donating investigator's lab reports they chose high-expressing mice as breeders, made the line homozygous, and bred homozygous mice together for many generations prior to sending to The Jackson Laboratory Repository. Upon arrival, mice were bred with C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony.

Allele

Symbol: Tg(Tagln-Tfpi)1661Rdsi
Name: transgene insertion 1661, Robert D Simari
MGI accession ID: MGI:5308413
Generation method: Transgenic
Attributes: Inserted expressed sequence
Marker symbol: Tg(Tagln-Tfpi)1661Rdsi
Marker name: transgene insertion 1661, Robert D Simari
Chromosome: UN
Strain of origin: C57BL/6
Expressed genes: Tfpi,tissue factor pathway inhibitor,mouse, laboratory
Molecular note: The transgene was designed with the 441 bp mouse SM22alpha (transgelin; Tagln) promoter fragment upstream of a mouse tissue factor pathway inhibitor (Tfpi) cDNA sequence encoding the TFPIalpha isoform (TFPIalpha is the predominant TFPI protein isoform in humans). Mice with the highest expression of transgenic TFPI mRNA were identified (founder line 1661).