bioRxiv Science⌕ Search

Biology subjects

Cariboni, A.

Publications and source records attributed to Cariboni, A..

3 recordsLinked to original sources

Integrated CHARGE syndrome models reveal epigenetic modulators of reproductive phenotypes

Loss-of-function variants in CHD7 cause CHARGE syndrome (CS), a rare developmental disorder showing multisystem malformations, including reproductive defects linked to gonadotropin-releasing hormone (GnRH) neuron dysfunction. CHD7 encodes a chromatin remodeler essential for early transcriptional regulation across various tissues. Currently, no pharmacological treatments exist, and approaches aimed at identifying tissue-specific CHD7 targets are also lacking, making CS treatment an unmet clinical need. To explore mechanisms relevant to CS-associated reproductive defects, we established a dual screening platform combining CRISPR-engineered Chd7-depleted mouse GnRH neurons with a Caenorhabditis elegans chd-7 mutant showing reproductive abnormalities. Transcriptomic and functional analyses of Chd7-deficient cells revealed impaired cellular processes along with dysregulation of semaphorin (Sema) genes, key regulators of GnRH neuron development. A screen of 234 epigenetic modulators in C. elegans identified compounds modifying aberrant mutant phenotype, two of which also rescued cellular defects and Sema expression in vitro. Altogether, these findings indicate that CHD7 deficiency reshapes neuroendocrine-relevant pathways and that selected compounds modulate CS-associated phenotypes across species, with SEMA signalling emerging as candidate druggable downstream pathway in CS requiring further mechanistic validation.

developmental biology↗

ARHGEF6-dependent cytoskeletal regulation underlies a conserved program of forebrain interneuron development

The molecular programs coordinating inhibitory interneuron migration, maturation, and survival during forebrain development remain incompletely understood. Here we investigate ARHGEF6, a RAC1/CDC42 guanine nucleotide exchange factor linked to X-linked intellectual disability (XLID46) and previously studied only at postsynaptic compartments, and reveal an earlier, conserved role in forebrain interneuron development. ARHGEF6 is selectively enriched in the inhibitory lineage during the peak of interneuron generation and migration. Its loss in mice reduces the number of cortical and hippocampal interneurons, disrupts tangential migration, increases developmental cell death, and impairs morphological and electrophysiological maturation. Strikingly, ARHGEF6-knockout human iPSC-derived organoids and assembloids mirror these deficits exhibiting increased apoptosis, reduced neuronal output, disorganized growth cones, impaired neurite branching, and disrupted migratory dynamics. These cross-species findings reframe ARHGEF6 as an early, essential orchestrator of inhibitory circuit assembly and reveal a conserved cytoskeletal program whose disruption produces the excitatory-inhibitory imbalance linked to cognitive dysfunction.

developmental biology↗

Diversity within olfactory sensory derivatives revealed by the contribution of Dbx1 lineages

In vertebrates, the embryonic olfactory epithelium contains progenitors that will give rise to distinct classes of neurons, including olfactory sensory neurons (OSN, involved in odor detection), vomeronasal sensory neurons (VSN, responsible for pheromone sensing) and GnRH neurons that control the hypothalamic-pituitary-gonadal axis. Currently, these three neuronal lineages are usually believed to emerge from uniform pools of progenitors. Here we found that the homeodomain transcription factor Dbx1 is expressed by neurogenic progenitors in the developing and adult mouse olfactory epithelium. We demonstrate that Dbx1 itself is dispensable for neuronal fate specification and global organization of the olfactory sensory system. Using lineage tracing we characterize the contribution of Dbx1 lineages to OSN, VSN and GnRH neuron populations and reveal an unexpected degree of diversity. Furthermore, we demonstrate that Dbx1-expressing progenitors remain neurogenic in the absence of the proneural gene Ascl1. Our work therefore points to the existence of distinct neurogenic programs in Dbx1-derived and other olfactory lineages.

developmental biology↗