Bone marrow-specific loss of

Area of Science:

• Hematology
• Oncology
• Molecular Biology

Background:

• Primary myelofibrosis (PMF) pathogenesis involves JAK-STAT pathway activation, but JAK inhibitors lack curative potential.
• Abelson interactor 1 (Abi-1) was previously identified as a tumor suppressor.
• Other molecular mechanisms beyond JAK-STAT signaling likely contribute to MPN pathophysiology.

Purpose of the Study:

• To investigate the role of Abelson interactor 1 (Abi-1) in the development of myeloproliferative neoplasms (MPNs).
• To determine if Abi-1 loss contributes to primary myelofibrosis (PMF) pathogenesis.
• To identify novel signaling pathways involved in PMF.

Main Methods:

• Generated a novel mouse model with bone marrow-specific deletion of Abi1.
• Performed noncompetitive and competitive bone marrow transplant experiments to assess hematopoietic stem cell function.
• Analyzed signaling pathway activity (SFKs, STAT3, NF-κB) in mouse models and patient samples (CD34+ progenitors, granulocytes) from PMF patients.

Main Results:

• Bone marrow-specific deletion of Abi1 in mice induced an MPN-like phenotype resembling human PMF.
• Abi1 loss led to increased activity of Src family kinases (SFKs), STAT3, and NF-κB signaling.
• Impaired hematopoietic stem cell self-renewal and fitness were observed in Abi1-deficient models.
• PMF patient samples showed decreased ABI1 transcript levels and increased SFKs, STAT3, and NF-κB activity.

Conclusions:

• Loss of Abi-1 function is linked to hyperactive SFKs/STAT3/NF-κB signaling in PMF.
• This signaling axis represents a potential regulatory module in PMF pathophysiology.
• Targeting the SFKs/STAT3/NF-κB pathway may offer new therapeutic strategies for PMF.