Smarcd1, also known as BAF60a, is a member of the SWI/SNF chromatin-remodeling complex family. It regulates the transcription of target genes by altering chromatin structure, playing essential roles in various biological processes such as cell differentiation, development, and disease-related pathways [6].

In murine hematopoiesis, acute deletion of Smarcd1 in adult hematopoiesis leads to lymphopenia, with a near-complete absence of early lymphoid progenitors and mature B and T cells, while myeloid and erythroid lineages remain unaffected. This indicates its crucial role in lymphoid cell fate specification, achieved by interacting with the E2a transcription factor at proximal promoters and regulating distal enhancer activity [1]. In breast cancer, both high and low expression of Smarcd1 correlate with positive clinical outcomes, while intermediate expression significantly reduces survival probability. Small perturbations in its expression level can reduce metastasis in mouse models and alter splicing programs relevant to the ER+/HER2-enriched breast cancer subtype [2,3]. In injured MES23.5 DA cells, knockdown of Smarcd1 inhibits the effect of Six2 on GDNF expression, decreasing cell viability and increasing apoptosis, while overexpression has the opposite effect [4]. In human glioblastoma cells, depletion of Smarcd1 promotes cell proliferation, invasion, and chemoresistance, while enhanced expression inhibits these malignant phenotypes [5].

In conclusion, Smarcd1 is an essential chromatin remodeler. Its study through gene-knockout (KO) or conditional-knockout (CKO) mouse models has revealed its significance in lymphoid cell fate determination, breast cancer metastasis, protection of dopaminergic neurons, and regulation of glioblastoma malignant phenotypes, providing insights into potential therapeutic strategies for related diseases.

References:

1. Priam, Pierre, Krasteva, Veneta, Rousseau, Philippe, Kmita, Marie, Lessard, Julie A. 2024. Smarcd1 subunit of SWI/SNF chromatin-remodeling complexes collaborates with E2a to promote murine lymphoid specification. In Developmental cell, 59, 3124-3140.e8. doi:10.1016/j.devcel.2024.08.007. https://pubmed.ncbi.nlm.nih.gov/39232562/

2. Ross, Christina, Gong, Li-Yun, Jenkins, Lisa M, Majocha, Megan, Hunter, Kent W. 2024. SMARCD1 is an essential expression-restricted metastasis modifier. In Communications biology, 7, 1299. doi:10.1038/s42003-024-07018-3. https://pubmed.ncbi.nlm.nih.gov/39390150/

3. Ross, Christina, Gong, Li-Yun, Jenkins, Lisa M, Majocha, Megan, Hunter, Kent. 2024. SMARCD1 is a "Goldilocks" metastasis modifier. In bioRxiv : the preprint server for biology, , . doi:10.1101/2024.01.24.577061. https://pubmed.ncbi.nlm.nih.gov/38410477/

4. Gao, Jin, Qin, Deng-Li, Tang, Chuan-Xi, Song, Cheng-Jie, Zhang, Can-Tang. 2021. Smarcd1 antagonizes the apoptosis of injured MES23.5 DA cells by enhancing the effect of Six2 on GDNF expression. In Neuroscience letters, 760, 136088. doi:10.1016/j.neulet.2021.136088. https://pubmed.ncbi.nlm.nih.gov/34233203/

5. Zhu, Yihao, Wang, Handong, Fei, Maoxing, Niu, Wenhao, Zhang, Li. 2020. Smarcd1 Inhibits the Malignant Phenotypes of Human Glioblastoma Cells via Crosstalk with Notch1. In Molecular neurobiology, 58, 1438-1452. doi:10.1007/s12035-020-02190-z. https://pubmed.ncbi.nlm.nih.gov/33190170/

6. Inoue, Chisato, Zhao, Chong, Tsuduki, Yumi, Nomura, Masatoshi, Katakura, Yoshinori. 2017. SMARCD1 regulates senescence-associated lipid accumulation in hepatocytes. In NPJ aging and mechanisms of disease, 3, 11. doi:10.1038/s41514-017-0011-1. https://pubmed.ncbi.nlm.nih.gov/28868154/