PHARMACEUTICAL BLOCKADE OF THE CANNABINOID TYPE 1 RECEPTOR IMPACTS CYTOKINE SIGNALING IN BETA CELLS TO AMELIORATE INSULITIS IN TYPE 1 DIABETES

WREVEN E; PACINI A; RUIZ DE ADANA MS; GMYR V.; KERR-CONTE J.; EGAN JM; PATTOU F.; GONZALEZ MARISCAL I.

Burdeos

Congreso; 23ª Reunión Anual de la Sociedad Española de Investigación sobre Cannabinoides; 2023

Introduction: The blockade of the cannabinoid type 1 receptor (CB1R) protects insulin-producing beta cells from stress factors such as hyperglycemia, fatty acids, and proinflammatory cytokines while enhancing their secretory function. In mice, genetic ablation of CNR1 (gene encoding CB1R) in beta cells prevents immune cell infiltration into the islets, a distinctive form of inflammation named insulitis that precedes the onset of autoimmune type 1 diabetes (T1D). New immunosuppressive treatments such as anti-CD3 (Teplizumab) have emerged to delay the progression of T1D, however, beta cell function remains vulnerable and unprotected, compromising their efficacy and applicability only to a small number of patients with diagnosed susceptibility (genetic predisposition and presence of at least 2 distinct autoantibodies against beta cells). We have shown that the peripheral inverse agonist JD-5037 prevented insulitis and preserved beta cell function in mice and humans, concomitant with the prevention of cytokine-mediated nitric oxide (NO) production. Herein we investigated the therapeutic potential of S-MRI-1867, a dual inhibitor of iNOS and peripheral blocker of CB1R, for the treatment of T1D.Methods: Human insulitis ex vivo model: human islets and peripheral blood mononuclear cells were isolated from cadaveric donors, and 3D-cultured in solubilized extracellular matrix gel with/out cytokines (IL-1β, TNF-α, IFN-γ). CNR1 was ablated via CRISPR/Cas9. CB1R was blocked using S-MRI-1867. NO production was determined using DAF-FM staining and imaged by microscopy. Islet function was measured as glucose-stimulated insulin secretion (GSIS) in a perifusion system. Infiltration of immune cells into the islets was monitored by microscopy. Pre-T1D (dysglycemic) NOD/ShiLtJ female mice were treated for 4 weeks with S-MRI-1867, and blood glucose and beta cell function were monitored to assess progression to T1D.Results: Genetic ablation of CNR1 in islets prevented cytokines-mediated NO production and delayed insulitis ex vivo in humans. Dual blockade of CB1R and iNOS fully prevented insulitis in human ex vivo even at lower concentrations than JD-5037. S-MRI-1867 not only protected beta cell function upon cytokine treatment but also strongly enhanced it by 3.7-fold GSIS. In vivo, treatment with S-MRI-1867 protected beta cell functional mass, which was 1.8-fold more responsive to glucose to secrete insulin. S-MRI-1867, when given for 4 weeks, significantly delayed the onset of T1D, with only 1 mouse reported as diabetic at the age when 90% of NOD/ShiLtJ mice are diabetic (p < 0.0001 by Mantel-Cox).Conclusions: These results suggest that dual peripheral CB1R/iNOS inhibition is a potent therapeutic strategy for T1D with strong potential for its translation to human.