MYC Promotes Bone Marrow Stem Cell Dysfunction in Fanconi Anemia.

Area of Science:

• Hematology
• Molecular Biology
• Genetics

Background:

• Fanconi anemia (FA) is a rare genetic disorder characterized by bone marrow failure (BMF).
• Dysfunctional hematopoietic stem and progenitor cells (HSPCs) are the underlying cause of BMF in FA.
• The specific molecular drivers of HSPC dysfunction in FA remain incompletely understood.

Purpose of the Study:

• To identify key molecular determinants contributing to BMF in Fanconi anemia.
• To investigate the role of MYC expression in the pathogenesis of FA-related bone marrow failure.

Main Methods:

• Single-cell transcriptome profiling of primary HSPCs from FA patients.
• Analysis of gene expression patterns, including TP53, TGF-β, and MYC.
• Pharmacological inhibition of MYC using (+)-JQ1 in patient-derived and mouse models.

Main Results:

• FA patient HSPCs exhibit overexpression of p53, TGF-β pathway genes, and notably, MYC.
• Distinct HSPC subpopulations with high TP53 or MYC expression were identified in FA bone marrow.
• MYC inhibition reduced clonogenic potential of FA HSPCs but rescued stress in mouse models, indicating MYC promotes proliferation and DNA damage.
• MYC-high HSPCs display downregulated cell adhesion genes, correlating with increased egress from bone marrow.

Conclusions:

• MYC overexpression is a significant factor impairing HSPC function in Fanconi anemia.
• Targeting MYC may offer a therapeutic strategy to mitigate bone marrow failure and HSPC exhaustion in FA.
• Understanding MYC's role provides insights into the complex mechanisms underlying Fanconi anemia pathogenesis.