Evaluation of cannabinoid effect on mouse alveolar macrophages

The cannabinoid system is composed of cannabinoid receptors, endocannabinoids, and their synthesis and metabolizing enzymes. The isolation of the phytocannabinoids CBD (J Am Chem Soc. (1940) 62:196) and Δ9-THC (J Am Chem Soc. (1964) 86:1646), occurred even before the description of the receptors and endocannabinoids. Since then, the effects of these substances on the respiratory system have been studied (Respir Res. 2023; 24(1):95). Alveolar macrophages play a crucial role in pulmonary immunity and reside in an environment where they are widely exposed to cannabis smoke during its use. In this sense, the literature lacks data regarding the individual or combined activations of CB1 and CB2 receptors in alveolar macrophages, including their expression by this cell type. Thus, the objective of this project is to characterize the expression of CB1 and CB2 receptors in C57BL/6 murine alveolar macrophages and investigate how the activation of these receptors influences classic macrophage responses such as the production of cytokines and eicosanoids. Our data indicate that alveolar macrophages express CB1 and CB2, with a higher expression of CB2 receptors. We analyzed the production of cytokines IL-6, IL-1β, and TNF-α by ELISA in conditioned supernatants with 2-AG and anandamide (10μM), ACEA and HU308 (10nM), subsequently stimulated with LPS (100ng/mL) overnight. Our preliminary results indicate that endocannabinoids inhibited the production of IL-6. The presence of leukotriene B4 and prostaglandin E2 in the conditioned supernatants with 2-AG and anandamide for 10 minutes and then stimulated with LPS (2μg/mL) for 1 hour was determined by EIA. Our preliminary results suggest that 2-AG, per se, is capable of inducing the production of this eicosanoids, while anandamide doesn’t induce any changes. Thus, these results suggest that endocannabinoids can modulate the inflammatory response of activated macrophages, altering the production of cytokines and eicosanoids. CEUA 008/24