TSHR Gene Editing    

Thyroid-stimulating hormone (TSH) is a trophic hormone released from the anterior pituitary, which stimulates the thyroid to produce thyroid hormones. TSH is mediated by the thyroid-stimulating hormone receptor (TSHR). TSHR expression has also been detected in many non-thyroidal cells, including adipocytes, lymphocytes, neuronal cells, retroocular fibroblasts, and astrocytes.

TSHR Mutations

Loss-of-function mutations in TSHR are associated with resistance to TSH and a range of thyroid dysfunction, from a compensated state with elevated TSH levels and normal thyroid hormone levels to overt congenital hypothyroidism with thyroid hypoplasia. To date, more than 60 different inactivating TSHR mutations have been described, which lead to congenital nonautoimmune hyperthyrotropinaemia (a condition with variable prevalence depending on the population tested). The comprehensive and appropriate clinical investigation of hyperthyroid patients and an adequate TSHR mutation screening are necessary prerequisites for the in vivo classification of a TSHR mutation as constitutively active and for its correlation with hyperthyroidism. In particular, the patient and possibly all hyperthyroid and euthyroid family members should have a comprehensive history for thyroid and other diseases in the cases with contradictory clinical phenotype/in vitro results.

TSHR and Graves' Disease

As most autoimmune diseases, inherited predisposition to Graves' disease (GD) is polygenic with the main pathogenic genes being located in the HLA region. The clinical characteristics of GD are abnormal growth and over-activity of the thyroid gland, leading to pathologically high levels of thyroid hormones. In addition to the effects on the thyroid, about 20% of patients with bona fide GD develop the ocular manifestation of the disease, which is called thyroid-associated ophthalmopathy (TAO). TAO represents a process of connective tissue activation and remodeling which can result in disfigurement and blindness. In that process, TSIs acting through locally expressed TSHR in tissues peripheral to the thyroid, have been related to the inflammation and expansion that occurs within the boney orbit. Functional TSHR has been detected in orbital fat, orbital fibroblasts, and extraocular muscles. Therefore, there is strong evidence to support the involvement of TSHR and the actions of TSI in thyroid overactivity and orbital pathology in GD.

TSHR is of special significance as it codes for the target of TSHR stimulating antibodies (TSAbs), which have clear pathogenicity and are an exception in autoimmunity by being stimulating rather than neutral, blocking, or cytotoxic. This is surprising because the generation of stimulating TSHR antibodies by immunisation of laboratory animals has been remarkably difficult, indicating an underlying mechanism that favours stimulating over neutral or blocking anti-TSHR antibodies must be operating in GD patients. In addition, after HLA, TSHR is the gene most tightly associated with GD.

TSHR Antagonists

Small molecule agonists and antagonists of TSHR have been described, mostly from the laboratory of Gershengorn and his colleagues reported a small molecule partial agonist termed Org41841, which binds to transmembrane domains of TSH and LH receptors. This molecule was modified subsequently to yield NIIDDK/CEB-52, which shows inhibitory activity toward the actions of TSH and TSIs in primary cultures of human thyrocytes. The inverse TSHR agonist, NCGC00161856, inhibits basal and TSH-dependent cAMP production in HEK-EM 293 cells. This inhibition was competitive. The molecule was shown to attenuate constitutive expression of TSHR, thyroglobulin, thyroperoxidase, and sodium iodide symporter in thyroid epithelial cells. As a small molecule inverse agonist for TSHR, its development has broken new ground.

ANTAG3 (NCGC00242364), a TSHR antagonist exhibiting activity in vivo, was administered orally to female BALB/c mice and was found to reduce serum levels of protein unbound T4 and to inhibit the expression of thyroid proteins in mice treated with thyrotropin releasing hormone. Another group showed that Org 274179-0, a TSHR antagonist, can inhibit cAMP induced by GD-IgG, rhTSH, and M22 in adipocyte differentiated orbital fibroblasts. Therefore, a series of small molecules and their derivatives have recently been developed that can act as agonists and antagonists of TSHR. In terms of agonists, they might possess clinical utility in stimulating residual thyroid cancer. The antagonists can be used to treat conditions such as hyper-functioning thyroid nodules, and in GD and TAO.

TSHR Gene Editing Services

CRISPR/Cas9 Platform^CB, one of the leading biotechnological companies specializing in gene editing, is dedicated to offering comprehensive CRISPR/Cas9 gene-editing services to a wide range of genomics researchers. Based on our platform, we can help you effectively TSHR gene deleted, inserted or point mutated in cells or animals by CRISPR/Cas9 technology.

• TSHR Gene Knockout: We offer TSHR gene knockout cell line and knockout animal model generation service with high quality. Typically, we develop CRISPR-mediated gene editing cell lines including HEK239T, Hela, HepG2, U87, but we can use other cell lines according to your requirements. Our one-stop KO animal model generation service covers from sgRNA design and construction, pronuclear microinjection to Founders genotyping and breeding.
• TSHR Gene Knockin: CRISPR/Cas9 Platform^CB provides the one-stop TSHR knock-in cell line and knockout animal model generation services, including point mutation and gene insertion. Our expert staff has succeeded in dozens of TSHR knock-in cell line generation projects, including stem cells, tumor cells and even difficult-to-handle cells. We also have extensive experience in incorporating CRISPR/Cas9 technology into animal models, which have been fully recognized by our clients.

If you have any questions, please feel free to contact us.

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