The Therapeutic Paradox of Endocannabinoid Immunomodulation: Molecular Mechanisms and Strategic Frameworks

The endocannabinoid system (ECS) is increasingly recognized as a central regulator of immune homeostasis, integrating neural, metabolic, and immune signaling to maintain physiological equilibrium. This Perspective examines the "therapeutic paradox" of endocannabinoid immunomodulation, whereby anti-inflammatory and tissue-protective effects are mechanistically linked to transient immunosuppression. Although cannabinoid receptor 2 (CB2) is the primary mediator of immune regulation, growing evidence indicates that cannabinoid receptor 1 (CB1) also contributes to inflammatory control in both the central nervous system and peripheral tissues. Activation of CB2 suppresses inflammatory signaling through Gi/o-mediated inhibition of adenylate cyclase, reduced cyclic adenosine monophosphate (cAMP) signaling, and repression of nuclear factor kappa B (NF-κB)-dependent transcription. While these mechanisms limit pathological inflammation and promote tissue protection, they simultaneously attenuate innate and adaptive immune functions required for effective pathogen clearance. Across neuroinflammatory disorders, inflammatory bowel disease, hepatic injury, sepsis, cancer, and systemic inflammatory syndromes, the ECS shifts immune responses toward resolution at the cost of reduced antimicrobial readiness. We synthesize the molecular mechanisms underlying this therapeutic paradox, including macrophage polarization, lymphocyte reprogramming, and tissue-specific immune adaptations, and discuss strategies for developing endocannabinoid-based therapeutics that preserve anti-inflammatory efficacy while minimizing immunosuppressive liabilities.