Seminars

Work in my laboratory is based on the assumptions that we do not know yet how all physiological functions are regulated and that mouse genetics by allowing to identify novel inter-organ communications is the most efficient ways to identify novel regulation of physiological functions. We test these two contention through the study of bone which is the organ my lab has studied since its inception. Based on precise cell biological and clinical reasons that will be presented during the seminar we hypothesized that bone should be a regulator of energy metabolism and reproduction and identified a bone-derived hormone termed osteocalcin that is responsible of these regulatory events. The study of this hormone revealed that in addition to its predicted functions it also regulates brain size, hippocampus development, prevents anxiety and depression and favors spatial learning and memory by signaling through a specific receptor we characterized. As will be presented, we elucidated some of the molecular events accounting for the influence of osteocalcin on brain and showed that maternal osteocalcin is the pool of this hormone that affects brain development. Subsequently and looking at all the physiological functions regulated by osteocalcin, i.e., memory, the ability to exercise, glucose metabolism, the regulation of testosterone biosynthesis, we realized that are all need or regulated in the case of danger. In other words it suggested that osteocalcin is an hormone needed to sense and overcome acute danger. Consonant with this hypothesis we next showed this led us to demonstrate that bone via osteocalcin is needed to mount an acute stress response through molecular and cellular mechanisms that will be presented during the seminar. overall, an evolutionary appraisal of bone biology, this body of work and experiments ongoing in the lab concur to suggest 1] the appearance of bone during evolution has changed how physiological functions as diverse as memory, the acute stress response but also exercise and glucose metabolism are regulated and 2] identified bone and osteocalcin as its molecular vector, as an organ needed to sense and response to danger.

The corpus callosum is the largest fibre tract in the brain of placental mammals and connects the two cerebral hemispheres. Corpus callosum dysgenesis is a developmental brain disorder that is commonly genetic and occurs in approximately 1:4000 live births. It is easily diagnosed by MRI or prenatal ultrasound and is found in isolation or together with other brain anomalies, or with other organ system defects in a large number of different congenital syndromes. Callosal dysgenesis is a structural brain wiring disorder that can impact brain function and cognition in heterogeneous ways. We aim to understand how early developmental mechanisms lead to circuit alterations that ultimately impact behaviour and cognition. Translated to Spanish by MD and Medical interpreter Trinidad Ott. El cuerpo calloso es el tracto de fibras más grande del cerebro de los mamíferos placentarios y conecta los dos hemisferios cerebrales. La disgenesia del cuerpo calloso es un trastorno del desarrollo del cerebro que comunmente es genético y ocurre en aproximadamente 1: 4000 nacidos vivos. Se diagnostica fácilmente mediante resonancia magnética o ecografía prenatal y se encuentra aislado o junto con otras anomalías cerebrales, o con otros defectos del sistema de órganos en un gran número de síndromes congénitos diferentes. La disgenesia callosa es un trastorno estructural del cableado cerebral que puede afectar la función cerebral y la cognición de formas heterogéneas. Nuestro objetivo es comprender cómo los primeros mecanismos del desarrollo conducen a alteraciones en los circuitos que, en última instancia, afectan el comportamiento y la cognición. Traducción al español por la Doctora e Intérprete Médica Trinidad Ott.