The role of cannabinoid ligands in neurodegenerative diseases: Emerging anti-inflammatory, immunomodulation and disease-modifying perspectives.

Neurodegenerative diseases (NDs) constitute a growing global health burden driven by population aging and remain without disease-modifying therapies. Although chronic neuroinflammation and aberrant protein aggregation are widely recognized as shared pathological hallmarks of major NDs - including Alzheimer's, Parkinson's, Huntington's diseases and multiple sclerosis - the causal relationships linking immunoinflammatory signaling to neurodegenerative progression remain contentious. Therapeutic strategies targeting neuroinflammation have thus far yielded limited clinical success, underscoring the need for mechanistically grounded and context-specific interventions. The endocannabinoid system (ECS) is a key regulator of synaptic function, glial activity, and immune homeostasis in the central nervous system (CNS), and its dysregulation has been consistently reported in neurodegenerative settings. However, ECS alterations across NDs are heterogeneous and often disease- and stage-dependent, with conflicting findings regarding cannabinoid receptor expression, endocannabinoid tone, and functional outcomes. Moreover, while preclinical studies demonstrate robust anti-inflammatory and neuroprotective effects of cannabinoid ligands, clinical translation has been constrained by issues of receptor specificity, psychoactive side effects, limited brain penetration, and an incomplete understanding of long-term ECS modulation. In this Review, we critically evaluate current evidence linking ECS signaling to neuroinflammatory mechanisms in neurodegeneration, highlighting both convergent pathways and unresolved controversies. We discuss the translational implications of ECS-targeted strategies, including the development of selective receptor modulators, allosteric and/or bitopic/dualsteric ligands, and enzyme inhibitors, as well as emerging approaches to mitigate adverse effects and improve therapeutic precision. By integrating mechanistic insights with clinical challenges, this Review delineates key obstacles and opportunities for advancing ECS-based interventions toward disease-modifying therapies for neurodegenerative disorders.