IL-34, the rationale for its expression in physiological and pathological conditions

Area of Science:

• Immunology
• Cell Biology
• Molecular Biology

Background:

• Interleukin-34 (IL-34) is a cytokine that binds to the colony-stimulating factor 1 receptor (CSF-1R).
• IL-34 shares CSF-1R with CSF-1, challenging previous notions of CSF-1R signaling.
• Other IL-34 receptors include protein-tyrosine phosphatase (PTP)-ζ and Syndecan-1.

Purpose of the Study:

• To comprehensively review the physiological and pathological roles of IL-34.
• To compare and contrast IL-34 with CSF-1 regarding receptor binding and downstream signaling.
• To explore the reasons behind IL-34's varied expression patterns in different diseases.

Main Methods:

• Literature review of existing studies on IL-34.
• Analysis of IL-34's interactions with CSF-1R, PTP-ζ, and Syndecan-1.
• Examination of IL-34's role in various diseases, including cancer, brain disorders, and dermal conditions.

Main Results:

• IL-34 and CSF-1 induce similar downstream signaling via CSF-1R, leading to distinct physiological outcomes.
• IL-34 is implicated in cancer progression and therapy resistance by promoting myeloid cell remodeling and reducing immunotherapy efficacy.
• IL-34 expression is downregulated in certain brain and dermal disorders.

Conclusions:

• IL-34 exhibits complex and context-dependent roles in human health and disease.
• Further research is needed to fully elucidate the multifaceted nature of IL-34.
• Targeting IL-34 may offer therapeutic potential in diseases where it plays a detrimental role.