Neurotrophins and Galectin-3: Hidden Keys in Neuroinflammation-A Narrative Review

Galectin-3 (Gal-3) is a multifunctional molecule that exerts pleiotropic effects in inflammatory responses and contributes to the pathogenesis of numerous immune-mediated diseases. Although Gal-3 has been known for more than five decades, it remains a lectin with intriguing and not yet fully elucidated properties. The existing body of evidence underscores the importance of Gal-3 in the regulation of homeostatic and inflammatory processes. Neurotrophins are traditionally recognized as key regulators of neuronal development, survival, and synaptic plasticity; nevertheless, accumulating evidence indicates that they also play important roles in immune regulation and neuroimmune communication. Importantly, neurotrophins are also produced by immune cells, including monocytes, macrophages, lymphocytes, and basophils, which express functional neurotrophin receptors including tropomyosin receptor kinase A (TrkA), tropomyosin receptor kinase A (TrkB), and p75 neurotrophin receptor (p75NTR). In this narrative review, we synthesize current evidence on neuroinflammation, neurotrophins, and Gal-3, with a particular focus on the molecular mechanisms involved in the crosstalk between neurotrophins and Gal-3 or immune cells. We further examine how this neuroimmune-neurotrophic crosstalk contributes to the pathogenesis of psychiatric and neurodegenerative disorders, as well as other neurological conditions. Finally, we discuss the emerging therapeutic potential of targeting neurotrophins and Gal-3 as modulators of neuroinflammation.