Introduction:

• The thyroid-stimulating hormone receptor (TSHR) is a G protein-coupled receptor (GPCR) primarily expressed in the thyroid and testes. Under physiological conditions, its main function is to bind thyroid-stimulating hormone (TSH) released from the anterior pituitary, thereby regulating thyroid growth and development. The binding of TSH to TSHR stimulates the proliferation of thyroid follicular cells and modulates the expression of differentiation markers such as thyroglobulin (Tg), thyroid peroxidase (TPO), and the sodium-iodide symporter (NIS), all of which are essential for thyroid hormone synthesis. Mutations in TSHR can lead to thyroid eye disease (TED). These mutations may cause either gain-of-function (constitutive TSH-independent activation) or loss-of-function (impaired TSH sensitivity). Additionally, TSHR is overexpressed in certain tumor cells, including thyroid cancer and gliomas. TSH can promote tumor cell proliferation and immune evasion through TSHR signaling.

Gene targeting strategy:

• In the B-CAG-LSL-hTSHR A mice(C), the human TSHR A CDS was inserted into the Rosa26 locus under the control of the CAG promoter. The construct also includes STOP cassette. Upon Cre-mediated recombination, the STOP cassette is excised, thereby allowing the CAG promoter to drive the expression of the TSHR A.

Protein expression analysis:

• Human TSHR was not detected in the heart, liver, spleen, lung, kidney, brain, colon, thyroid, eye, testis, and skeletal muscle of wild-type BALB/cCrSlcNifdc and homozygous B-CAG-hTSHR A mice(C), indicating no leaky expression occurred before Cre‑mediated induction.

Application:

• This product is used for pharmacodynamics and safety evaluation of ophthalmic diseases such as thyroid-associated ophthalmopathy.

Gene targeting strategy for B-CAG-hTSHR A mice(C). In the B-CAG-hTSHR A mice(C), the human TSHR A CDS was inserted into the Rosa26 locus under the control of the CAG promoter. The construct also includes  STOP cassette. Upon Cre-mediated recombination, the STOP cassette is excised, thereby allowing the CAG promoter to drive the expression of the TSHR A.

IHC analysis of TSHR protein expression in homozygous B-CAG-hTSHR A mice(C). Various tissue lysates were collected from wild-type BALB/cCrSlcNifdc mice (+/+) and homozygous B-CAG-hTSHR A mice(C) (H/H), and then analyzed by IHC with anti-TSHR antibody (Abcam, ab218108). Human TSHR was not detected in the heart, liver, spleen, lung, kidney, brain, colon, thyroid, eye, testis, and skeletal muscle of wild-type BALB/cCrSlcNifdc and homozygous B-CAG-hTSHR A mice(C), indicating no leaky expression occurred before Cre‑mediated induction.