Biology subjects

Moissidis, M.

Publications and source records attributed to Moissidis, M..

3 recordsLinked to original sources

bioRxiv2024

A postnatal molecular switch drives the activity-dependent maturation of parvalbumin interneurons

Cortical neurons are specified during embryonic development but often only acquire their mature properties at relatively late stages of postnatal development. This delay in terminal differentiation is particularly prominent for fast-spiking parvalbumin-expressing (PV+) interneurons, which play critical roles in regulating the function of the cerebral cortex. We found that the maturation of PV+ interneurons is triggered by neuronal activity and mediated by the transcriptional cofactor peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC-1). Developmental loss of PGC-1 prevents PV+ interneurons from acquiring unique structural, electrophysiological, synaptic, and metabolic features and disrupts their diversification into distinct subtypes. PGC-1 exerts its function as a master regulator of the differentiation of PV+ interneurons by directly controlling gene expression through a transcriptional complex that includes ERR{gamma} and Mef2c. Our results uncover a molecular switch that translates neural activity into a specific transcriptional program promoting the maturation of PV+ interneurons at the appropriate developmental stage.

neuroscience↗

bioRxiv2023

Somatostatin interneurons control the timing of developmental desynchronization in cortical networks

Synchronous neuronal activity is a hallmark of the early developing brain. In the mouse cerebral cortex, activity decorrelates during the second week of postnatal development, progressively acquiring the characteristic pattern of sparse coding underlying the integration of multidimensional sensory information. The maturation of inhibition seems critical for this process, but the specific types of interneurons involved in this crucial transition of network activity in the developing cortex remain unknown. Using in vivo volumetric and longitudinal two-photon calcium imaging during the period that precedes the change from highly synchronous to decorrelated activity, we identify somatostatin-expressing (SST+) interneurons as critical modulators of this switch. Modulation of the activity of SST+ cells accelerates or delays the decorrelation of cortical network activity, a process that involves regulating the degree of maturation of parvalbumin-expressing (PV+) interneurons. SST+ cells critically link sensory inputs with local circuits controlling the neural dynamics in the developing cortex while modulating the integration of other interneurons into nascent cortical circuits.

neuroscience↗

bioRxiv2019

Multipotent radial glia progenitors and fate-restricted intermediate progenitors sequentially generate diverse cortical interneuron types

GABAergic interneurons deploy numerous inhibitory mechanisms that regulate cortical circuit operation, but the developmental programs that generate diverse interneuron types are not yet well understood. We carried out a comprehensive genetic fate mapping of the radial glial progenitors (RGs) and intermediate progenitors (IP) in the medial ganglionic eminence (MGE) in mice. We reveal that Nkx2.1+ RGs are multipotent and mediate two consecutive waves of neurogenesis, each sequentially generating different sets of interneuron types that laminate the neocortex in an inside-out-inside order. The first wave begins early and is restricted to the caudal MGE, has limited neurogenic window and capacity, and involves mostly apical IPs. The second wave begins later throughout the MGE, has an extended time course and large neurogenic capacity, and features a large set of fate-restricted basal IPs that amplify and diversify interneurons. Chandelier cells are generated toward the end of each wave and laminate in an outside-in order. Therefore, separate pools of multipotent RGs deploy temporal cohorts of IPs to sequentially generate diverse interneuron types.

neuroscience↗