AI Article Synopsis

  • The ASXL1 gene is crucial for regulating gene expression and differentiation in blood cells, and its mutations are linked to severe blood disorders.
  • Research using techniques to silence ASXL1 revealed that its absence impairs the formation of specific immune cell types (CD11b(+) and CD15(+)), indicating problems with granulomonocytic differentiation.
  • Further analysis showed a significant dysregulation of gene expression and pathways in ASXL1-deficient cells, particularly affecting genes related to the PRC2 complex, which is important for gene repression and differentiation.

Article Abstract

The ASXL1 gene encodes a chromatin-binding protein involved in epigenetic regulation in haematopoietic cells. Loss-of-function ASXL1 mutations occur in patients with a range of myeloid malignancies and are associated with adverse outcome. We have used lentiviral-based shRNA technology to investigate the effects of ASXL1 silencing on cell proliferation, apoptosis, myeloid differentiation and global gene expression in human CD34(+) cells differentiated along the myeloid lineage in vitro. ASXL1-deficient cells showed a significant decrease in the generation of CD11b(+) and CD15(+) cells, implicating impaired granulomonocytic differentiation. Furthermore, colony-forming assays showed a significant increase in the number of multipotent mixed lineage colony-forming unit (CFU-GEMM) colonies and a significant decrease in the numbers of granulocyte-macrophage CFU (CFU-GM) and granulocyte CFU (CFU-G) colonies in ASXL1-deficient cells. Our data suggests that ASXL1 knockdown perturbs human granulomonocytic differentiation. Gene expression profiling identified many deregulated genes in the ASXL1-deficient cells differentiated along the granulomonocytic lineage, and pathway analysis showed that the most significantly deregulated pathway was the LXR/RXR activation pathway. ASXL1 may play a key role in recruiting the polycomb repressor complex 2 (PRC2) to specific loci, and we found over-representation of PRC2 targets among the deregulated genes in ASXL1-deficient cells. These findings shed light on the functional role of ASXL1 in human myeloid differentiation.

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http://dx.doi.org/10.1111/bjh.12217DOI Listing

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