Sleep deprivation (SD) impairs information processing through alterations of prefrontal cortex (PFC) function, yet the molecular underpinnings of this process remain poorly understood. We previously s Show more
Sleep deprivation (SD) impairs information processing through alterations of prefrontal cortex (PFC) function, yet the molecular underpinnings of this process remain poorly understood. We previously showed that SD disrupts sensorimotor gating by elevating prefrontal levels of the neurosteroid allopregnanolone (AP), a positive allosteric modulator of GABA-A receptors. Here we identify a complementary, mechanistically independent process whereby SD alters GABA-A currents in the PFC of mice and rats. SD reduced membrane expression of the chloride exporter KCC2, leading to intracellular chloride accumulation and a depolarizing shift in GABA-A receptor reversal potential that weakened GABAergic inhibition. Pharmacological normalization of chloride homeostasis with bumetanide fully rescued SD-induced deficits in sensorimotor gating and information encoding. SD also upregulated BDNF, and intra-PFC antagonism of its receptor TrkB restored KCC2 expression and normalized information processing, identifying BDNF-TrkB signaling as an upstream driver of chloride dysregulation. Notably, blocking AP synthesis rescued behavioral deficits without correcting chloride imbalance, confirming mechanistic independence. Finally, combined administration of AP and a KCC2 blocker produced information-processing deficits akin to those induced by SD. These findings identify TrkB-dependent disruption of prefrontal chloride homeostasis as a druggable mechanism underlying sleep loss-induced cognitive dysfunction. Show less
CTNNB1/β-catenin mutations and activation of Wnt/β-catenin pathway are frequent in adult adrenocortical tumors (ACT), but data on childhood ACT are lacking. The aim of the study was to investigate the Show more
CTNNB1/β-catenin mutations and activation of Wnt/β-catenin pathway are frequent in adult adrenocortical tumors (ACT), but data on childhood ACT are lacking. The aim of the study was to investigate the presence of Wnt/β-catenin pathway abnormalities in childhood ACT. Clinicopathological findings and outcome of 62 childhood ACT patients were analyzed regarding CTNNB1 mutations and the expression of Wnt-related genes (CTNNB1; WNT4, a Wnt ligand; SFRP1, DKK3, and AXIN1, Wnt inhibitors; TCF7, a transcription factor; and MYC and WISP2, target genes) by quantitative PCR and immunohistochemistry. CTNNB1-activating mutations were found in only four of 62 ACT (6%), all of them harboring TP53 mutation. There was association between the presence of CTNNB1 mutations and death (P = 0.02). Diffuse β-catenin accumulation was found in 71% of ACT, even in ACT without CTNNB1 mutations. Compared to normal adrenals, ACT presented increased expression of CTNNB1 (P = 0.008) and underexpression of Wnt inhibitor genes: DKK3 (P < 0.0001), SFRP1 (P = 0.05), and AXIN1 (P = 0.04). With regard to Wnt/β-catenin target genes, ACT presented increased expression of WISP2 but lower expression of MYC. Higher overall survival was associated with underexpression of SFRP1 (P = 0.01), WNT4 (P = 0.004), and TCF7 (P < 0.01). CTNNB1 mutations are not common in childhood ACT but appear to associate with poor prognosis. Nevertheless, most ACT exhibit increased expression of β-catenin and WISP2 and reduced expression of Wnt inhibitor genes (DKK3, SFRP1, and AXIN1). Thus, in addition to CTNNB1 mutations, other genetic events affecting the Wnt/β-catenin pathway may be involved in childhood adrenocortical tumorigenesis. Show less