Glover, H. J. | bioRxiv Science

bioRxiv2021

Single-cell genomics reveals region-specific developmental trajectories underlying neuronal diversity in the prenatal human hypothalamus

The development and diversity of neuronal subtypes in the human hypothalamus has been insufficiently characterized. We sequenced the transcriptomes of 40,927 cells from the prenatal human hypothalamus spanning from 6 to 25 gestational weeks and 25,424 mature neurons in regions of the adult human hypothalamus, revealing a temporal trajectory from proliferative stem cell populations to mature neurons and glia. Developing hypothalamic neurons followed branching trajectories leading to 170 transcriptionally distinct neuronal subtypes in ten hypothalamic nuclei in the adult. The uniqueness of hypothalamic neuronal lineages was examined developmentally by comparing excitatory lineages present in cortex and inhibitory lineages in ganglionic eminence from the same individuals, revealing both distinct and shared drivers of neuronal maturation across the human forebrain. Cross-species comparisons to the mouse hypothalamus identified human-specific POMC populations expressing unique combinations of transcription factors and neuropeptides. These results provide the first comprehensive transcriptomic view of human hypothalamus development at cellular resolution. One-Sentence SummaryUsing single-cell genomics, we reconstructed the developmental lineages by which precursor populations give rise to 170 distinct neuronal subtypes in the human hypothalamus.

neuroscience↗

bioRxiv2020

Regulation of intracellular signaling and neuron function by Bardet-Biedl Syndrome proteins in patient-specific iPSC-derived neurons

Bardet-Biedl Syndrome (BBS) is a rare autosomal recessive disorder caused by mutations in genes encoding components of the primary cilium and characterized by hyperphagic obesity. We developed a cellular model of BBS using induced pluripotent stem cell (iPSCs)-derived hypothalamic arcuate-like neurons. BBS mutations BBS1M390R and BBS10C91fsX95 did not affect neuron differentiation efficiency but caused morphological defects including impaired neurite outgrowth and longer primary cilia. Expression of intact BBS10 normalized cilia length. Single-cell RNA sequencing (scRNA-seq) of BBS1M390R hypothalamic neurons identified several down regulated pathways including insulin and cAMP signaling, and axon guidance. In agreement with scRNA-seq data, insulin-induced AKT phosphorylation at Thr308 was reduced in BBS1M390R and BBS10c91fsX95 human fibroblasts and iPSC-derived neurons, as well as in BBS10 knockdown iPSC-derived neurons. Overexpression of intact BBS10 fully restored insulin receptor tyrosine phosphorylation in BBS10c91fsX95 neurons. Mutations in BBS1 and BBS10 impaired leptin-mediated p-STAT3 activation in both human primary fibroblasts and iPSC-derived hypothalamic neurons. Correction of the BBS mutation by CRISPR rescued leptin signaling. POMC expression in BBS1M390R and BBS10 C91fsX95 iPSC-derived hypothalamic neurons was downregulated, as was hypothalamic Pomc in BBS1M390R knockin (KI) mice. In the aggregate, these data provide insights into the anatomic and functional mechanisms by which components of the BBsome in CNS primary cilia mediate effects on energy homeostasis.

cell biology↗