Prolactin integrates immune homeostasis, hematopoietic dynamics, and iron metabolism as a pleiotropic immuno-neuroendocrine hormone
Background
Traditionally known for its roles in lactation and reproduction, Prolactin (PRL) is increasingly recognized as a critical immuno-neuroendocrine integrator. Many chronic inflammatory and autoimmune conditions, such as systemic lupus erythematosus and rheumatoid arthritis, involve dysregulated immune responses, often exacerbated by stress and hormonal imbalances. Understanding the complex interplay between neuroendocrine signals and the immune system is crucial for developing targeted therapies. This review addresses the gap in fully characterizing PRL's pleiotropic effects beyond its classical functions, particularly its context-dependent roles in immunity, hematopoiesis, and inflammation.
Study Design
This comprehensive review synthesized mechanistic insights into prolactin biology, examining its diverse hematopoietic and immunologic roles. Researchers critically evaluated current controversies surrounding its context-dependent actions and discussed emerging therapeutic strategies targeting PRL signaling. The work integrates findings from numerous studies to provide a holistic understanding of prolactin's pleiotropic effects, including its interactions with the hypothalamic-pituitary-adrenal axis, dopaminergic pathways, and sex steroids, thereby linking neuroendocrine signals with immune responses.
Results
Prolactin exerts its actions through the prolactin receptor (PRLR), activating intracellular signaling cascades including JAK2/STAT5, MAPK/ERK, and PI3K/Akt pathways. These networks influence lymphocyte survival, cytokine production, macrophage activation, dendritic cell maturation, and hematopoietic progenitor cell expansion. Prolactin demonstrates a context-dependent duality, exhibiting both pro-inflammatory and immunoregulatory functions. Dysregulated PRL signaling is implicated in autoimmune disorders such as systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis.
Prolactin integrates neuroendocrine signals with immune responses by interacting with the hypothalamic-pituitary-adrenal axis, dopaminergic pathways, and sex steroids, highlighting its central role in immuno-neuroendocrine communication.
Key Findings
- Prolactin is a pleiotropic immuno-neuroendocrine hormone with broad regulatory effects on innate and adaptive immunity, hematopoiesis, and inflammatory homeostasis.
- Prolactin acts through the
prolactin receptor(PRLR), activatingJAK2/STAT5,MAPK/ERK, andPI3K/Aktsignaling pathways. - These signaling networks influence
lymphocyte survival,cytokine production,macrophage activation,dendritic cell maturation, andhematopoietic progenitor cell expansion. - Prolactin exhibits context-dependent duality, demonstrating both pro-inflammatory and immunoregulatory functions.
- Dysregulated prolactin signaling is implicated in autoimmune disorders like systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis.
Why It Matters
This review significantly advances our understanding of prolactin's multifaceted roles, moving beyond its traditional reproductive functions to its critical involvement in immune and hematopoietic regulation. For biohackers and clinicians, this implies that PRL levels could be a key biomarker and potential therapeutic target in managing autoimmune conditions and chronic inflammation. Understanding its context-specific actions is vital for developing precision-based immunomodulatory interventions, potentially leading to novel strategies for conditions like Hidradenitis Suppurativa (HS) where stress and hormonal dysregulation are implicated. This research underscores the need to consider neuroendocrine axes when addressing immune dysregulation.
prolactin
immunology
neuroendocrinology
hematopoiesis
inflammation
autoimmune-disorders