Stochastic Loss of Silencing of the Imprinted Ndn/NDN Allele, in a Mouse Model and Humans with Prader-Willi Syndrome, Has Functional Consequences
Genomic imprinting is a process that causes genes to be expressed from one allele only according to parental origin, the other allele being silent. Diseases can arise when the normally active alleles are not expressed. In this context, low level of expression of the normally silent alleles has been considered as genetic noise although such expression has never been further studied. Prader-Willi Syndrome (PWS) is a neurodevelopmental disease involving imprinted genes, including NDN, which are only expressed from the paternally inherited allele, with the maternally inherited allele silent. We present the first in-depth study of the low expression of a normally silent imprinted allele, in path…
Inactivation of Socs3 in the Hypothalamus Enhances the Hindbrain Response to Endogenous Satiety Signals via Oxytocin Signaling.
Leptin is an adipocyte-derived hormone that controls energy balance by acting primarily in the CNS, but its action is lost in common forms of obesity due to central leptin resistance. One potential mechanism for such leptin resistance is an increased hypothalamic expression of Suppressor of cytokine signaling 3 (Socs3), a feedback inhibitor of the Jak-Stat pathway that prevents Stat3 activation. Ample studies have confirmed the important role of Socs3 in leptin resistance and obesity. However, the degree to which Socs3 participates in the regulation of energy homeostasis in nonobese conditions remains largely undetermined. In this study, using adult mice maintained under standard diet, we d…
Hypothalamus-specific deletion of socs3 in adult mice enhances hindbrain sensitivity to endogenous satiety signals via oxytocin signaling
Communication sans actes n° 469 (1 page) ; http://www.neurosciences.asso.fr/V2/colloques/SN11/; Leptin is a major contributor to long-term energy homeostasis, through an intracellular transduction pathway involving activation of Stat3 and its feedback inhibitor Socs3, which limits Stat3 activation. Previous studies have shown that Socs3 haploinsufficiency or socs3 deletion in the whole brain or in selective neuronal populations triggers an increased sensitivity to exogenous leptin, through increased Stat3 activation, and protects against diet-induced obesity in mice fed a high fat diet. Intriguingly however, no phenotype was detected when Socs3 mutant mice were maintained under standard die…