• The CIDE family of proteins includes CIDEA, CIDEB, and CIDEC/Fsp27. The CIDEB gene is most highly expressed in human liver cells, where it has been hypothesized to enable fat buildup by helping enlarge fat-storage structures called "lipid droplets. CIDEB-deficient mice have a lean phenotype with lower levels of plasma TAG, free fatty acids, insulin, and leptin, higher plasma adiponectin, increased whole-body metabolism, and reduced white adipose tissue (WAT) mass. RGC researchers found that individuals with loss-of-function mutations in one copy of the CIDEB gene have about a 53% reduced risk of nonalcoholic liver disease and about a 54% reduced risk of nonalcoholic cirrhosis.
• Gene targeting strategy for B-hCIDEB mice. The exons 1-5 of the mouse Cideb gene that encoded the whole molecule (ATG to STOP codon), including 3’UTR were replaced by human exons 1-7 including 3’UTR in B-hCIDEB mice. The promoter and 5’UTR region of the mouse gene were replaced by human counterparts, while mouse Cideb gene transcription and translation will be disrupted.
• Mouse Cideb mRNA was detectable only in wild-type C57BL/6JNifdc mice. Human CIDEB mRNA was detectable only in homozygous B-hCIDEB mice, but not in wild-type C57BL/6JNifdc mice.

Gene targeting strategy for B-hCIDEB mice. The exons 1-5 of the mouse Cideb gene that encoded the whole molecule (ATG to STOP codon), including 3’UTR were replaced by human exons 1-7 including 3’UTR in B-hCIDEB mice. The promoter and 5’UTR region of the mouse gene were replaced by human counterparts, while mouse Cideb gene transcription and translation will be disrupted.

Species-specific analysis of CIDEB gene expression in wild-type C57BL/6 mice and heterozygous humanized B-hCIDEB mice by RT-PCR. Liver cells were collected from wild-type C57BL/6 mice (+/+) and heterozygous B-hCIDEB mice (H/+). Mouse Cideb mRNA was detectable in wild-type C57BL/6JNifdc mice and heterozygous B-hCIDEB mice. Human CIDEB mRNA was detectable only in heterozygous B-hCIDEB mice, but not in wild-type C57BL/6JNifdc mice.

Western blot analysis of CIDEB protein expression in homozygous B-hCIDEB mice. Various tissue lysates were collected from wild-type C57BL/6JNifdc mice (+/+) and homozygous B-hCIDEB mice (H/H), and then analyzed by western blot with anti-CIDEB antibody (Proteintech: 27600-1). 40 μg total proteins were loaded for western blotting analysis. CIDEB was detected in the liver, stomach, kidney, small intestine, and large intestine of wild-type C57BL/6JNifdc mice and homozygous B-hCIDEB mice, as the antibody cross-recognized both human and mouse CIDEB.

The inhibitory efficiency of the nucleic acid drugs against human CIDEB in homozygous B-hCIDEB mice. B-hCIDEB mice were randomly divided into four groups (male, 6 weeks old). The human CIDEB-targeted siRNA and control were administered to the mice individually. The mice were sacrificed on day 7 and day 21, and the liver tissues were collected to detect the expression level of human CIDEB mRNA by qPCR. (A) The schematic diagram of experimental processing. (B) The expression of human CIDEB mRNA in the liver. Data was shown as mean ± SEM, analyzed by one way-ANOVA (*p<0.05, **p<0.01, ***p<0.001, ****p<0.0001). Data provided by a client.