Galectin-3 in Alzheimer's disease: pathological roles, biomarker potential, and therapeutic implications.

Alzheimer's disease (AD) is a neurodegenerative disease characterized by amyloid-beta (Aβ) accumulation, tau pathology, and chronic neuroinflammation, leading to cognitive decline and neurodegeneration. Currently available treatments are liable to provide symptomatic relief; hence, researchers are focused on finding some novel molecular targets for developing targeted therapies, and also some biomarkers for early detection. Emerging evidence suggests that Galectin-3 (Gal-3) serves as a key regulator of microglial activation, exhibiting both neuroprotective and neurotoxic effects, depending on the stage of disease. The overexpression of Gal-3 leads to increased neuroinflammation, oxidative stress, and mitochondrial dysfunction, accelerating disease progression while initially promoting Aβ clearance and suppressing immune response. Moreover, Gal-3 has been associated with tau hyperphosphorylation and aggregation, hence exacerbating synaptic dysfunction and neuronal damage. Elevated levels of Gal-3 in cerebrospinal fluid (CSF) and serum correlate with disease severity, indicating its potential as a biomarker for early diagnosis and disease monitoring. Establishing Gal-3 inhibitors as a potential therapeutic target, several preclinical studies indicate their ability to lower Aβ and tau accumulation by regulating pro-inflammatory signaling and enhancing clearance mechanisms. This approach reduces neuroinflammation by suppressing microglial activation and improves cognitive function by preserving neuronal function and lowering oxidative stress. This review is intended to discuss the intricate role of Gal-3 in AD pathology, such as Aβ aggregation, tau pathology, neuroinflammation, oxidative stress, and microglial activation. Further, it explores the therapeutic strategies that Gal-3 could serve as a novel biomarker for tracing the disease, and reviews potential therapeutic approaches through Gal-3 inhibition for AD management.