• TL1A binds to death receptor 3 (DR3) to provide stimulatory signals for downstream signaling pathways, thereby regulating the proliferation, activation, apoptosis of effector cells, and the production of cytokines and chemokines. Soluble decoy receptor 3 (DcR3) may neutralize the effects of soluble TL1A (sTL1A)/DR3. In addition, DcR3 can inhibit apoptosis, reduce inflammation, and prevent tissue damage by neutralizing LIGHT and FasL.
• Integrin α4β7 is composed of a 150 kD (α4 or CD49d) and a 130 kD (β7) heterodimer, also known as CD49d/β7 or LPAM-1. Belonging to the Ig superfamily, it is found on the majority of peripheral lymphocytes and subsets of thymocytes and bone marrow cells (including mast cell progenitors). Integrin α4β7 binds its ligands, VCAM-1 (CD106), MAdCAM-1 and fibronectin, and plays an important role in lymphocytes adhesion and the direction of migration of blood lymphocytes to the intestine and associated lymphoid tissues.
• The genome of the mouse Tl1a gene encoding the extracellular domain was replaced with its human TL1A counterpart in B-hTL1A/hDR3/hMADCAM1 mice. The genome of the mouse Dr3 gene encoding the full-length protein was replaced with human DR3 counterpart in B-hTL1A/hDR3/hMADCAM1 mice. The genome of the mouse Madcam1 gene encoding the extracellular domain was replaced with its human MADCAM1 counterpart in B-hTL1A/hDR3/hMADCAM1 mice.
• Human TL1A, DR3, and MADCAM1 protein were only detectable in homozygous B-hTL1A/hDR3/hMADCAM1 mice.
• Application: This product is used for pharmacodynamics and safety evaluation of  drugs.

Gene targeting strategy for B-hTL1A/hDR3/hMADCAM1 mice.

The exons 1-4 of mouse Tl1a gene that encode extracellular domain were replaced by human counterparts in B-hTL1A/hDR3/hMADCAM1 mice. The genomic region of mouse Tl1a gene that encodes transmembrane domain and cytoplasmic portion was retained. The promoter, 5’UTR and 3’UTR region of the mouse gene were also retained. The TL1A expression was driven by endogenous mouse Tl1a promoter, while mouse Tl1a gene transcription and translation will be disrupted.

The exons 1-10 of mouse DR3 gene that encode the whole molecule (ATG to STOP codon), including promoter, 5’UTR and 3’UTR were replaced by human counterparts in B-hTL1A/hDR3/hMADCAM1 mice. The human DR3 expression was driven by human DR3 promoter, while mouse DR3 gene transcription and translation will be disrupted.

The exons 1-5 of mouse Madcam1 gene that  encode the extracellular region were replaced by human MADCAM1 exons 1-5 in B-hTL1A/hDR3/hMADCAM1 mice. The genomic region of mouse Madcam1 gene that encodes transmembrane domain and cytoplasmic portion was retained. The promoter, 5’UTR and 3’UTR region of the mouse gene were also retained. The MADCAM1 expression was driven by endogenous mouse Madcam1 promoter, while mouse Madcam1 gene transcription and translation will be disrupted.

B-hTL1A/hDR3/hMADCAM1 mice were derived from mating B-hTL1A/hDR3 mice (113082) and B-hMADCAM1 mice (111627).

Strain specific TL1A expression analysis in homozygous B-hTL1A/hDR3/hMADCAM1 mice by ELISA. Bone marrow-derived dendritic cells were isolated from wild-type C57BL/6JNifdc mice(+/+) and homozygous B-hTL1A/hDR3/hMADCAM1 mice(H/H;H/H;H/H) and stimulated with 1 μg/mL LPS in vitro for 24 h, then the supernatants were collected and the levels of soluble TL1A were measured using a species-specific mouse and human TL1A ELISA kit. Soluble mouse TL1A was detectable in wild-type C57BL/6JNifdc mice. Soluble human TL1A was exclusively detectable in homozygous B-hTL1A/hDR3/hMADCAM1 mice but not in wild-type mice. ND: not detectable.

Strain specific DR3 expression analysis in wild-type C57BL/6JNifdc mice and homozygous B-hTL1A/hDR3/hMADCAM1 mice by flow cytometry. Splenocytes were collected from wild-type C57BL/6JNifdc mice (+/+) and B-hTL1A/hDR3/hMADCAM1 mice (H/H;H/H;H/H) stimulated with anti-mouse CD3ε antibody and anti-mouse CD28 antibody in vivo for 24 h, protein expression was analyzed with anti-mouse DR3 antibody (Biolegend, 144407) and anti-human DR3 antibody (Biolegend, 307105) by flow cytometry. Mouse DR3 was detectable on CD4+ T cells of wild-type C57BL/6JNifdc mice, human DR3 was detectable on CD4+ T cells of homozygous B-hTL1A/hDR3/hMADCAM1 mice.

Strain specific DR3 expression analysis in wild-type C57BL/6JNifdc mice and homozygous B-hTL1A/hDR3/hMADCAM1 mice by flow cytometry. Splenocytes were collected from wild-type C57BL/6JNifdc mice (+/+) and B-hTL1A/hDR3/hMADCAM1 mice (H/H;H/H;H/H) stimulated with anti-mouse CD3ε antibody and anti-mouse CD28 antibody in vivo for 24 h, protein expression was analyzed with anti-mouse DR3 antibody (Biolegend, 144407) and anti-human DR3 antibody (Biolegend, 307105) by flow cytometry. Mouse DR3 was detectable on Treg cells of wild-type C57BL/6JNifdc mice, human DR3 was detectable on Treg cells of homozygous B-hTL1A/hDR3/hMADCAM1 mice.

Strain specific MADCAM1 expression analysis in homozygous B-hTL1A/hDR3/hMADCAM1 mice by Immunohistochemistry (IHC). Colon and small intestine  were collected from wild-type C57BL/6JNifdc (+/+) and homozygous B-hTL1A/hDR3/hMADCAM1 mice (H/H;H/H;H/H), protein expression was analyzed by IHC with species-specific anti-mouse MADCAM1 antibody (Abcam, ab309487) and anti-human MADCAM1 antibody (Abcam, ab307737). Mouse MADCAM1 was detectable in vascular endothelial cell of colon and small intestine in wild-type C57BL/6JNifdc mice. Human MADCAM1 was exclusively detectable in vascular endothelial cell of colon and small intestine in B-hTL1A/hDR3/hMADCAM1 mice, but not in wild-type mice.