Thy1, also known as CD90, is a glycophosphatidylinositol (GPI)-anchored cell surface protein. It has been implicated in multiple biological processes, such as adipogenesis, cell-cell adhesion, and stem cell-related functions. It is also involved in pathways like epithelial-mesenchymal transition (EMT) and is associated with various diseases including cancer, obesity, and glomerulonephritis [2,3,4,6]. Genetic models, especially gene knockout (KO) mouse models, are valuable for studying its functions.

In mouse models, ablation of Thy1+ cells strongly impairs epidermal replenishment and wound repair, indicating that Thy1+ cells are non-redundant stem cells in the epidermis [1]. In adipogenesis, DNA methylation regulates Thy1 expression, and Thy1-knockout mice are prone to diet-induced obesity, highlighting the role of Thy1 in this process [3]. In nasopharyngeal carcinoma, constitutive expression of THY1 suppresses tumor invasion by inhibiting SRC activation and maintaining adherens junctions [4]. In arthritis, the CD34+THY1+ synovial fibroblast subset shows high osteogenic and chondrogenic potentials, and knockdown of THY1 in synovial fibroblasts impairs osteoblast differentiation [5].

In summary, Thy1 plays crucial roles in epidermal homeostasis, adipogenesis, tumor invasion, and joint tissue regeneration. The use of Thy1 KO mouse models has significantly contributed to understanding its functions in these biological processes and associated disease conditions, such as skin repair, obesity, cancer metastasis, and joint diseases.

References:

1. Koren, Elle, Feldman, Alona, Yusupova, Marianna, Shemesh, Tom, Fuchs, Yaron. 2022. Thy1 marks a distinct population of slow-cycling stem cells in the mouse epidermis. In Nature communications, 13, 4628. doi:10.1038/s41467-022-31629-1. https://pubmed.ncbi.nlm.nih.gov/35941116/

2. Yi, Changsheng, Zang, Nan, Gao, Limin, Ren, Fang. 2024. THY1 is a prognostic-related biomarker via mediating immune infiltration in lung squamous cell carcinoma (LUSC). In Aging, 16, 9498-9517. doi:10.18632/aging.205880. https://pubmed.ncbi.nlm.nih.gov/38819947/

3. Flores, E'Lissa M, Woeller, Collynn F, Falsetta, Megan L, Susiarjo, Martha, Phipps, Richard P. 2018. Thy1 (CD90) expression is regulated by DNA methylation during adipogenesis. In FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 33, 3353-3363. doi:10.1096/fj.201801481R. https://pubmed.ncbi.nlm.nih.gov/30376360/

4. Chen, Luo, Chau, Wai Yin, Yuen, Hei Tung, Lung, Maria Li, Lung, Hong Lok. 2023. THY1 (CD90) Maintains the Adherens Junctions in Nasopharyngeal Carcinoma via Inhibition of SRC Activation. In Cancers, 15, . doi:10.3390/cancers15072189. https://pubmed.ncbi.nlm.nih.gov/37046850/

5. Noda, Seiji, Hosoya, Tadashi, Komiya, Yoji, Mizoguchi, Fumitaka, Yasuda, Shinsuke. 2022. CD34+THY1+ synovial fibroblast subset in arthritic joints has high osteoblastic and chondrogenic potentials in vitro. In Arthritis research & therapy, 24, 45. doi:10.1186/s13075-022-02736-7. https://pubmed.ncbi.nlm.nih.gov/35168627/

6. Rohan, Paulo, Dos Santos, Everton Cruz, Abdelhay, Eliana, Binato, Renata. 2023. High Expression of THY1 in Intestinal Gastric Cancer as a Key Factor in Tumor Biology: A Poor Prognosis-Independent Marker Related to the Epithelial-Mesenchymal Transition Profile. In Genes, 15, . doi:10.3390/genes15010028. https://pubmed.ncbi.nlm.nih.gov/38254918/