B6-hLPA(CKI) Mice

Catalog Number: C001521

Strain Name: C57BL/6NCya-Gt(ROSA)26Sor^{em1(CAG-loxP-Stop-loxP-hLPA)}/Cya

Genetic Background: C57BL/6NCya

Reproduction: Homozygote x Homozygote

Strain Description

Lipoprotein A (LPA) is a type of particle similar to low-density lipoprotein (LDL) that is considered one of the risk factors for cardiovascular disease (CVD) such as atherosclerosis, coronary heart disease, stroke, etc ^[1]. LP(a) is similar in size and lipid content to LDL (low-density lipoprotein) and contains the lipoprotein ApoB-100. However, unlike LDL, LP(a) contains a variable-length lipoprotein called Apo(a), which covalently binds to ApoB-100 through a single disulfide bond. LP(a) plays an important role in systemic lipid transport, guiding inflammatory cells into blood vessel walls and leading to smooth muscle cell proliferation. Furthermore, it is involved in wound healing and tissue repair, interacting with the components of blood vessel walls and the extracellular matrix ^[2]. However, LP(a) can also cause arterial narrowing by adhering to the arterial wall, accelerating the formation of blood clots, and thereby triggering a series of pathological changes related to coronary heart disease, cardiovascular disease, atherosclerosis, thrombus formation, and stroke ^[3].

The plasma concentration of LP(a) is closely related to genetic factors and is primarily regulated by the LPA gene. Therefore, the LPA gene is an important potential target for cardiovascular disease treatment. The LPA gene encodes a serine protease that inhibits the activity of tissue-type plasminogen activator I. Fragments of this protein, generated through protein hydrolysis, can adhere to atherosclerotic lesions in arteries, promoting blood clot formation. The LPA gene is expressed in both humans and non-human primates but is not expressed in mice. Constructing mouse models expressing the human LPA gene is of significant importance for developing lipid-lowering drugs, which can drive the development of novel therapies for cardiovascular diseases. Currently, various novel therapies targeting the transcription rate of the LPA gene are under development, including small interfering RNA (siRNA) and antisense oligonucleotides (ASO) ^[4].

This strain was a conditional mouse model expressing the human LPA gene, where the ‘loxP-Stop-loxP-hLPA’ sequence was inserted into the intron 1 of the ROSA26 safe harbor locus. When this model is bred with tool mice expressing Cre recombinase, sequence recombination occurs in the Cre-positive cells and tissues of the offspring mice. After the Cre-recombinase-mediated deletion of the stop element (LSL), specific expression of the human LPA gene can be achieved. The B6-hLPA(CKI) mice can be used for research related to atherosclerosis, and thrombotic cardiovascular diseases, as well as the development, screening, and preclinical evaluation of human LPA gene-targeted drugs.

Strain Strategy

Figure 1. Gene editing strategy of B6-hLPA(CKI) mice. The “CAG promoter-loxP-PGK-Neo-6xSV40 pA-loxP-Kozak-Human LPA CDS-rBG pA” cassette was cloned into intron 1 of ROSA26.

Validation

1. Detection of human LPA gene expression

Figure 2. Expression of the human LPA gene in the liver of 8-week-old male B6-hLPA(CKI) mice (hLPA[CKI/+]) and B6-hLPA(CKI)/Alb-cre mice* (hLPA[CKI/+], Alb-cre). RT-qPCR results demonstrate that B6-hLPA(CKI)/Alb-cre mice, after deletion of the expression stop element (LSL) mediated by Cre recombinase, specifically express the human LPA gene in the liver. In contrast, B6-hLPA(CKI) mice that were not bred with Alb-Cre mice do not exhibit expression of the human LPA gene in the liver. (ND: Not detected)
*B6-hLPA(CKI)/Alb-cre mice (catalog number: C001522) are mice obtained by breeding B6-hLPA(CKI) mice (catalog number: C001521) with Alb-Cre mice (liver-specific Cre-expressing mice), resulting in liver-specific overexpression of the human LPA gene. Before mating with Alb-Cre mice, B6-hLPA(CKI) mice have silenced expression of the human LPA gene due to the expression stop element (LSL).

2. Detection of human LPA protein expression

Figure 3. ELISA detection of human LPA protein in the serum of 8-week-old male B6-hLPA(CKI) mice (hLPA[CKI/+]) and B6-hLPA(CKI)/Alb-cre mice (hLPA[CKI/+], Alb-cre). The results demonstrate that B6-hLPA(CKI)/Alb-cre mice exhibit significant expression of human LPA protein in their serum, whereas B6-hLPA(CKI) mice that were not bred with Alb-Cre mice do not show expression of human LPA protein.

References