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Biomedical subjects

Aparna Bhaduri

Publications and source records attributed to Aparna Bhaduri.

4 recordsLinked to original sources

Thalamic NRXN1-mediated input to human cortical progenitors drives excitatory neurogenesis.

The human cerebral cortex develops through coordinated signals from within the cortex and from other brain regions, including the thalamus. However, how thalamic neuronal projections influence early human cortical development remains less well-understood. In this study, we fused cortical and thalamic organoids to investigate how thalamic input shapes the maturation of human cortical cells. Using single-nuclei RNA-sequencing and cellular imaging, we found that thalamic input increases the production of cortical excitatory neurons. We identify neurexin-1 (NRXN1) as a mediator of physical contact between thalamic axons and cortical outer radial glia. Genetic knockout of thalamic NRXN1 reduced these contacts and attenuated the production of upper-layer excitatory neurons. These findings reveal a mechanism by which thalamic input regulates human cortical progenitors and shapes excitatory neuron production during development.

Animals

Metabolic atlas of early human cortex reveals glycolytic remodeling and pentose phosphate pathway control of cell fate transitions.

Cortical development involves rapid progenitor expansion and cell diversification supported by tightly regulated metabolic programs, yet these programs remain largely uncharacterized in human development. Here, we generated a metabolic atlas of the early human cortex using primary tissue and stem cell-derived cortical organoids. We observed dynamic changes in core metabolic functions, including an unexpected increase in glycolysis and pentose phosphate pathway (PPP) activity during late neurogenesis. Manipulation of glucose availability in cortical organoids altered cell-type composition, increasing outer radial glia (oRG) and inhibitory neuron populations. Pharmacological and genetic inhibition of PPP enzymes recapitulated these cell fate changes. Ribose was sufficient to rescue radial glia (RG) gene expression changes, revert organoid cell-type composition, and restore levels of ATP and hypotaurine. These data identify a critical role for the PPP in modulating RG cell fate specification and generate a resource for future exploration of additional metabolic pathways in human cortical development.

cell fate

The new frontier in understanding human and mammalian brain development.

Neurodevelopmental disorders that cause cognitive, behavioural or motor impairments affect around 15% of children and adolescents worldwide1, with diagnoses of profound autism and attention deficit hyperactivity disorder increasing in the USA and contributing to a major economic burden2,3. Yet the origins and mechanisms of these conditions remain poorly understood, limiting progress in therapies. Comprehensive cell atlases of the developing human brain, alongside those of model organisms such as mice and non-human primates, are now providing high-resolution measures of gene expression, cell-type abundance and spatial distribution. In this Perspective, we highlight recent studies that have identified novel developmental cell populations, revealed conserved and divergent patterns of cell genesis, migration and maturation across species, and begun testing hypotheses that link them to processes ranging from transcriptional control of cell fate specification to the emergence of complex behaviours. We present remaining conceptual and technical challenges and provide an outlook on how further studies of human and mammalian brain development can empower a deeper understanding of neurodevelopmental and neuropsychiatric disorders. Future efforts expanding to additional developmental stages, including adolescence, as well as whole-brain, multimodal and cross-species integration, will yield new insights into how development shapes the brain. These atlases promise to serve as essential references for unravelling mechanisms of brain function and disease vulnerability, and for advancing precision medicine.

Humans

Glucose modulates IRF6 transcription factor dimerization to enable epidermal differentiation.

Non-energetic roles for glucose are largely unclear, as is the interplay between transcription factors (TFs) and ubiquitous biomolecules. Metabolomic analyses uncovered elevation of intracellular glucose during differentiation of diverse cell types. Human and mouse tissue engineered with glucose sensors detected a glucose gradient that peaked in the outermost differentiated layers of the epidermis. Free glucose accumulation was essential for epidermal differentiation and required the SGLT1 glucose transporter. Glucose affinity chromatography uncovered glucose binding to diverse regulatory proteins, including the IRF6 TF. Direct glucose binding enabled IRF6 dimerization, DNA binding, genomic localization, and induction of IRF6 target genes, including essential pro-differentiation TFs GRHL1, GRHL3, HOPX, and PRDM1. These data identify a role for glucose as a gradient morphogen that modulates protein multimerization in cellular differentiation.

Cell Differentiation