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Martin Montalvo, A.

Publications and source records attributed to Martin Montalvo, A..

2 recordsLinked to original sources

Immunometabolic reprogramming by LRH-1/NR5A2 pharmacological activation resolves inflammation in immune cells of type 1 diabetes mellitus individuals and improves human islet engraftment and function

The intricate etiology of type 1 diabetes mellitus (T1D), marked by a detrimental cross-talk between the immune system and insulin-producing {beta}-cells, has impeded effective disease-modifying therapies. The discovery that pharmacological activation of the nuclear receptor LRH-1/NR5A2 can reverse hyperglycemia in mouse models of T1D by attenuating the autoimmune attack coupled to {beta}-cell survival/regeneration, prompted us to investigate whether immune tolerization could be achieved in individuals with T1D by LRH-1/NR5A2 activation as well as improving islet function/survival after xenotransplantation in mice. Pharmacological activation of LRH-1/NR5A2 induced a coordinated genetic and metabolic reprogramming of T1D macrophages and dendritic cells, shifting them from a pro-to an anti-inflammatory/tolerogenic phenotype. Regulatory T-cells were also expanded resulting in the impediment of cytotoxic T-cell proliferation. LRH-1/NR5A2 activation enhanced human islet engraftment and function in hyperglycemic immunocompetent mice. In summary our findings demonstrate the feasibility of re-establishing immune tolerance within a pro-inflammatory environment, opening a new therapeutic venue for T1D.

cell biology↗

LRH-1/NR5A2 regulates the PTGS2-PGE2-PTGER1 signalling axis contributing to islet survival and antidiabetic actions of the agonist BL001

We have previously described a role of LRH-1/NR5A2 in islet morphogenesis during postnatal development and reported that the treatment with BL001, an agonist of LRH-1/NR5A2, protects islets against-stress induced apoptosis and reverts hyperglycemia in 3 mouse models of Type 1 Diabetes Mellitus (T1DM). Islet transcriptome profiling revealed that most differentially expressed genes after BL001 treatment are involved in immunomodulation, among them, the increase in PTGS2/COX2 expression. Herein, we dissected the cellular and molecular branches of the BL001/LRH-1/NR5A2 signalling axis in order to chart the mode of action confering beta cell protection and hyperglycaemia reversion. We found that constitutive LRH-1/NR5A2 ablation within the insulin expression domain (RIP-Cre mouse model) caused a significant beta cell mass reduction characterized by blunted proliferation correlating with animal growth retardation, weight loss and hypoglycemia, leading to lethality before weaning. Using an inducible approach (pdx1PBCreER mouse model), specific deletion of LRH-1/NR5A2 in adult beta cells abolished the anti diabetic effect of BL001 in streptozotocin treated mice, correlating with complete beta-cell mass destruction. Additionally, BL001 induced Ptgs2 expression, was blunted in islets lacking LRH-1/NR5A2. The combined BL001/cytokine treatment did not further stimulate Ptgs2 expression above levels detected with cytokine alone yet secreted PGE2 levels were increased 5-fold. Inactivation of PTGS2 blunted induction of the target and its product PGE2 in islets treated with cytokines alone or with BL001. Importantly, PTGS2 inactivated islets were refractory to the BL001 protective effect under cytokine attack as evidenced by increased Bax expression levels, cytochrome C release and cleaved PARP. The PTGER1 antagonist ONO-8130, but not the PTGER4 antagonist L-161,982, negated BL001-mediated islet survival. Our results establish that the beneficial properties of BL001 against stress-induced cell death are specifically conveyed by LRH-1/NR5A2 activation in beta cells and downstream stimulation of the PTGS2-PGE2/PTGER1 signalling axis.

physiology↗