B6-hINHBE Mice

Catalog Number: C001533

Strain Name: C57BL/6NCya-Inhbe^tm1(hINHBE)/Cya

Genetic Background: C57BL/6NCya

Reproduction: Homozygote x Homozygote

One of Cyagen's HUGO-GT™ (Humanized Genomic Ortholog for Gene Therapy) Mouse Strains

Strain Description

Inhibin βE subunit (INHBE) is a member of the transforming growth factor-β (TGF-β) superfamily, highly specifically expressed in liver cells. The precursor protein of INHBE generates the inhibin β subunit after proteolytic processing. This protein is associated with various cellular processes, including cell proliferation, apoptosis, immune response, and hormone secretion. During the development of obesity and diabetes, the expression of INHBE protein inhibits the proliferation and growth of relevant cells in the pancreas and liver. Research has found a positive correlation between INHBE expression in the liver and insulin resistance as well as body mass index (BMI), suggesting that INHBE may be a liver factor involved in altering systemic metabolic status under conditions of obesity-related insulin resistance ^[1].

The studies conducted by Alnylam Pharmaceuticals and the Regeneron Genetics Center (RGC), respectively, revealed the close relationship between INHBE and fat regulation. The research demonstrated that rare loss-of-function variants in INHBE may protect the liver from the impact of inflammation, abnormal blood lipids, and type 2 diabetes by promoting healthy fat storage. Patients carrying such mutations exhibit more normal fat distribution, significantly reduced abdominal fat, improved metabolic conditions, and a decreased risk of cardiovascular diseases and type 2 diabetes ^[2-4]. These findings suggest that INHBE is a liver-specific negative regulator of fat storage. Inhibiting the expression of INHBE genes and proteins may be a potential strategy for treating metabolic disorders related to improper fat distribution and storage. Consequently, several small nucleic acid pharmaceutical companies, including Alnylam Pharmaceuticals, Arrowhead Pharmaceuticals, and Wave Life Sciences, are currently developing RNA interference (RNAi) drugs targeting INHBE for the treatment of conditions such as obesity ^[5-7].

RNAi drugs primarily include small interfering RNA (siRNA) and antisense oligonucleotides (ASO). siRNA targets and degrades specific mRNA, while ASO binds to the target mRNA, preventing its translation or inducing its degradation, thereby inhibiting the expression of the target gene. Considering the genetic differences between humans and animals, humanizing mouse genes can accelerate the clinical development of RNAi therapies targeting human INHBE. This strain is a mouse Inhbe gene humanized model and can be used to study therapies targeting INHBE for obesity. The homozygous B6-hINHBE mice are viable and fertile. In addition, based on the independently developed TurboKnockout fusion BAC recombination technology, Cyagen can also generate hot mutation models based on this strain and provide customized services for specific mutations to meet the experimental needs in pharmacology and other fields.

Strain Strategy

Figure 1. Gene editing strategy of B6-hINHBE mice. The sequences from the ATG start codon to 3'UTR of mouse Inhbe were replaced with the sequences from the ATG start codon to 3'UTR of human INHBE.

Validation

1. Detection of human INHBE gene and mouse Inhbe gene expression

Figure 2. Expression of human INHBE gene and mouse Inhbe gene in the liver of 6-week-old homozygous B6-hINHBE mice and wild-type (WT) mice. RT-qPCR results revealed significant expression of the human INHBE gene in both male and female B6-hINHBE mice livers, while no expression of the human INHBE gene was detected in wild-type mice. In wild-type mice liver, expression of the mouse Inhbe gene was present, whereas B6-hINHBE mice did not exhibit expression of the mouse Inhbe gene.
ND: Not detected.

 

2. Detection of human INHBE protein expression

Figure 3. Western blot results of human INHBE protein expression in the serum of 6-week-old homozygous B6-hINHBE mice and wild-type (WT) mice*. The results demonstrate significant expression of human INHBE protein in both male and female B6-hINHBE mice serum. Additionally, due to the potential cross-reactivity of the antibody with both human and mouse INHBE proteins, INHBE-positive bands were also detected in wild-type mouse samples.
*The INHBE antibody used in this assay is from Novus Biologicals (product number H00083729-B01P).

 

3. Small interfering RNA (siRNA) drug significantly reduces the expression of the human INHBE gene in the liver of B6-hINHBE mice.

Figure 4. Human INHBE gene expression in the liver of 7-week-old female homozygous B6-hINHBE mice after subcutaneous injection of siRNA drugs*. A single dose of siRNA drug (1 mg/kg) was administered, and liver tissue was collected for RT-qPCR analysis 5 days later. The results demonstrate a significant reduction in human INHBE gene expression in the liver of B6-hINHBE mice treated with the siRNA drug.
*The siRNA drug was provided by the Cyagen’s customer and targets the human INHBE gene to decrease its expression.

References