Adipoq-iCre Mice

Catalog Number: C001529

Strain Name: C57BL/6JCya-Adipoq^{em1(P2A-iCre)}/Cya

Genetic Background: C57BL/6JCya

Reproduction: Homozygote x Homozygote or Heterozygote x Heterozygote

Strain Description

The ADIPOQ gene-encoded adiponectin is a protein hormone produced exclusively by adipocytes (fat cells). It is transported through the bloodstream to muscle and liver cells. Adiponectin regulates various pathways related to fat storage and metabolism, including the modulation of blood glucose levels, fatty acid breakdown, brown adipocyte differentiation, and negative regulation of gluconeogenesis. By increasing insulin sensitivity and promoting fatty acid breakdown, adiponectin plays a crucial role in regulating glucose and fat metabolism. Additionally, it exhibits direct anti-diabetic, anti-atherosclerotic, and anti-inflammatory activities ^[1-2]. The mutation of the ADIPOQ gene is associated with adiponectin deficiency syndrome. Although the ADIPOQ gene is primarily expressed in adipose tissue, adiponectin is not only present in adipose tissue but is also widely distributed in various organs and tissues, including muscle, liver, intestines, male reproductive glands, and the brain ^[3-4].

The Adipoq-iCre mice are constructed by inserting a codon-improved Cre recombinase (iCre) element into the endogenous Adipoq gene of mice. The expression pattern of iCre recombinase is similar to the endogenous gene, and the expression of the endogenous gene remains unaffected. When this strain is crossed with mice containing loxP sites, sequence recombination mediated by the Cre recombinase between loxP sites can occur in the white adipose tissue (WAT) and brown adipose tissue (BAT) of its offspring.

Strain Strategy

The TGA stop codon was replaced with the “P2A-iCre” cassette.

Validation Data

a. Method

Adipoq-iCre mice were mated with Rosa26-LSL-tdTomato mice to generate double heterozygotes. Deletion of the “stop element (LSL)” results in tdTomato protein expression in Cre-positive cells. When the offspring mice reach 6 weeks of age, mouse white adipose tissue, brown adipose tissue, skeletal muscle, skin, lungs, heart, testicles, and ovarian tissues are collected and tdTomato protein distribution is analyzed by immunofluorescence (IF) to determine the expression of Cre recombinase.

b. Genotype

Cre+: Adipoq-iCre[KI/+];Rosa26-LSL-tdTomato[CKI/+];

Cre-: Rosa26-LSL-tdTomato[CKI/CKI].

c. Result

1) Expression of Cre recombinase in white adipose tissue and brown adipose tissue

Figure 1. Immunofluorescence (IF) staining of the white adipose tissue (WAT) and brown adipose tissue (BAT). The results reveal that in Cre+ mice, there is abundant red fluorescence from tdTomato in the adipocytes, indicating tdTomato expression mediated by Cre recombinase in these cells. Conversely, in Cre- mice, there is no activity of Cre recombinase in both white and brown adipose tissues.

2) Expression of Cre recombinase in skeletal muscle and skin

Figure 2. Immunofluorescence (IF) staining of the skeletal muscle and skin. The results indicate that in Cre+ mice, there is a partial red fluorescence signal present in the adipocytes adjacent to the skeletal muscle and skin, demonstrating that Cre-mediated recombination has occurred in these cells. Conversely, in Cre- mice, there is no activity of Cre recombinase detected in the skeletal muscle and skin.

3) Expression of Cre recombinase in lungs and heart

Figure 3. Immunofluorescence (IF) staining of the lungs and heart. The results indicate that in Cre+ mice, there is a partial fluorescence signal present in the adipocytes of the lungs and bronchi, while extremely low levels of fluorescence signal are observed in the heart. Conversely, in Cre- mice, there is no activity of Cre recombinase detected in both the lungs and heart.

4) Expression of Cre recombinase in testicles and ovaries

Figure 4. Immunofluorescence (IF) staining of the testicles and ovaries. The results indicate that in Cre+ mice, there is no observed red fluorescence signal in the testicles. However, in the ovarian perifollicular fat, ovarian stroma, and corpus luteum of Cre+ mice, there is a small amount of fluorescence signal, indicating tdTomato expression mediated by Cre recombinase in these cells. Conversely, in Cre- mice, there is no activity of Cre recombinase detected in both the testicles and ovaries.

d. Summary

In Adipoq-iCre mice, the expression of Cre recombinase is primarily concentrated in white adipose tissue (WAT) and brown adipose tissue (BAT). Additionally, there are partial recombination signals observed in the skeletal muscle, skin, lungs, and heart of mice. Based on histological assessment, these cell types in the mentioned tissues are likely adipocytes. Overall, this model can be utilized for tissue-specific research targeting adipose tissue.

Announcements

• The insertion site of the Cre recombinase gene expression cassette in this strain is located on chromosome 16. Please avoid breeding with gene-edited mice targeting genes on the same chromosome as the Cre mouse when conducting mating.

References
[1]Maeda K, Okubo K, Shimomura I, Funahashi T, Matsuzawa Y, Matsubara K. cDNA cloning and expression of a novel adipose specific collagen-like factor, apM1 (AdiPose Most abundant Gene transcript 1). Biochem Biophys Res Commun. 1996 Apr 16;221(2):286-9.
[2]Martinez-Huenchullan SF, Tam CS, Ban LA, Ehrenfeld-Slater P, Mclennan SV, Twigg SM. Skeletal muscle adiponectin induction in obesity and exercise. Metabolism. 2020 Jan;102:154008.
[3]Oliveira CS, Giuffrida FM, Crispim F, Saddi-Rosa P, Reis AF. ADIPOQ and adiponectin: the common ground of hyperglycemia and coronary artery disease? Arq Bras Endocrinol Metabol. 2011 Oct;55(7):446-54.
[4]Spranger J, Verma S, Göhring I, Bobbert T, Seifert J, Sindler AL, Pfeiffer A, Hileman SM, Tschöp M, Banks WA. Adiponectin does not cross the blood-brain barrier but modifies cytokine expression of brain endothelial cells. Diabetes. 2006 Jan;55(1):141-7.