Connexin Regulation and Modulation of Neural Stem Cell Differentiation Induced by Cell-Permeable Itaconate.

Neural stem cells (NSCs) are multipotent cells of the central nervous system (CNS) capable of self-renewal, differentiation, and responding to and shaping the surrounding microenvironment. Their continuous crosstalk with surrounding CNS cells is a key component of their therapeutic potential, particularly in tissue repair and regeneration. Communication in the CNS relies on complementary mechanisms, including connexins (Cxs)-based intercellular communication, to maintain homeostasis and coordinate responses to physiological and pathological stimuli. Itaconate, an endogenous shunt product of the tricarboxylic acid cycle, functions as an immunometabolite involved in inflammation and oxidative stress and has recently been implicated in neuroimmune modulation. Although itaconate influences several signalling cascades and is exchanged between cells and/or released into the extracellular milieu, its effects on Cxs expression in NSCs and whether the modulation of Cxs expression profile represents a driving factor in shaping cell fate remain unclear. Here, we investigated the effect of dimethyl itaconate, a cell-permeable esterified itaconate derivative, on the expression profile of Cxs in NSCs and its potential to modulate NSCs fate and differentiation. We found that dimethyl itaconate modulates Cxs expression in NSCs, increasing Cx36 levels, and promotes NSCs differentiation toward a neuronal phenotype, while inhibition of Cxs-based channels with carbenoxolone or mefloquine abolishes these dimethyl itaconate-induced effects. Collectively, these findings highlight a regulatory role for cell-permeable itaconate and contribute to the understanding of intercellular communication in the CNS microenvironment, providing insights into potential therapeutic strategies for CNS repair and regeneration.