Biology subjects

Diabira, D.

Publications and source records attributed to Diabira, D..

3 recordsLinked to original sources

bioRxiv2023

Leptin antagonism improves Rett syndrome phenotype in symptomatic male Mecp2-null mice.

Rett syndrome (RTT) is a severe X-linked neurodevelopmental disorder caused by mutations in MECP2. Elevated circulating levels of the adipocyte hormone leptin are consistently observed in patients and in mouse models, yet their contribution to disease progression has remained unclear. Here, we show that reducing leptin signaling--either pharmacologically or genetically-- significantly alleviates RTT-like phenotypes in Mecp2-deficient mice. In males, these interventions preserved general health, prevented weight loss, and improved breathing and locomotor functions. At the neuronal level, they restored excitatory/inhibitory balance in the hippocampus and somatosensory cortex and rescued hippocampal synaptic plasticity. In females, delaying the pathological rise of leptin levels postponed symptom progression. These findings uncover leptin as a key contributor to RTT pathophysiology and position leptin-targeted interventions as a promising therapeutic strategy for this currently untreatable disorder.

neuroscience↗

bioRxiv2020

Acute neonatal oxytocin impacts hippocampal network development and restores adult social memory deficits in a mouse model of autism spectrum disorder.

Oxytocin is a master regulator of the social brain. In some animal models of autism, notably in Magel2 tm1.1Mus-deficient mice, peripheral administration of oxytocin in infancy improves social behaviors until adulthood. However, neither the mechanisms responsible for social deficits nor the mechanisms by which such oxytocin administration has long-term effects are known. Here, we aimed to clarify these oxytocin-dependent mechanisms focusing on social memory performance. We showed that Magel2tm1.1Mus-deficient mice present a deficit in social memory and studied the hippocampal circuits underlying this memory. We showed a co-expression of Magel2 and oxytocin-receptor in the dentate gyrus and CA2/CA3 hippocampal regions. Then, we demonstrated: an increase of the GABAergic activity of CA3-pyramidal cells associated with an increase in the quantity of oxytocin-receptors and of somatostatin interneurons. We also revealed a delay in the GABAergic development sequence in Magel2tm1.1Mus-deficient pups, linked to phosphorylation modifications of KCC2. Above all, we demonstrated the positive effects of subcutaneous administration of oxytocin in the mutant neonates, restoring neuronal alterations and social memory. Although clinical trials are debated, this study highlights the mechanisms by which peripheral oxytocin-administration in neonates impacts the brain and demonstrates the therapeutic value of oxytocin to treat infants with autism spectrum disorders.

neuroscience↗

bioRxiv2019

Impaired KCC2 phosphorylation leads to neuronal network dysfunction and neurodevelopmental pathogenesis.

KCC2 is a vital neuronal K+/Cl- co-transporter that is implicated in the etiology of numerous neurological diseases. It is subject to developmental dephosphorylation at threonine 906 and 1007, the functional importance of which remains unclear. We engineered mice with heterozygous phospho-mimetic mutations T906E and T1007E (KCC2E/+) to prevent the normal developmental dephosphorylation of these sites. Immature (P15) but not juvenile (P30) KCC2E/+ mice exhibited altered GABAergic inhibition, an increased glutamate/GABA synaptic ratio, and higher seizure susceptibility. KCC2E/+ mice also had abnormal ultra-sonic vocalizations at P10-P12 and impaired social behavior at P60. Post-natal bumetanide treatment restored network activity at P15 but not social behavior at P60. Our data show that post-translational KCC2 regulation controls the GABAergic developmental sequence in vivo. The post-translational deregulation of KCC2 could be a risk factor for the emergence of neurological pathology and the presence of depolarizing GABA is not essential for manifestation of behavioral changes.

neuroscience↗