Biology subjects

Noya, S. B.

Publications and source records attributed to Noya, S. B..

3 recordsLinked to original sources

bioRxiv2025

Tanycyte Bmal1 sex-specifically regulates weight gain and hypothalamic neurogenesis in female mice

The hypothalamic radial-glia-like tanycyte population plays important and intertwined roles in feeding and metabolism, reproduction, and seasonality. Although these processes are circadian-regulated and clock genes reportedly show robust cycling along the 3rd ventricle, the role of the clock in tanycytes has not yet been examined. We report here that clock genes cycle with much higher amplitude in ventral tanycytes compared to more dorsal ependymocytes of the 3rd ventricle, and that specific disruption of the tanycyte clock can be achieved by adult Bmal1 deletion using the RaxCreER driver. Adult tanycyte Bmal1 deletion did not affect circadian rhythms of wheel-running and sleep, but did inhibit weight gain on high-fat diet in female mice. Altered tanycyte-derived hypothalamic neurogenesis, which can regulate feeding and weight gain by contributing new neurons to nearby feeding-relevant nuclei, is one mechanism that likely contributes to this phenotype. Fate mapping studies showed that female mice have higher baseline tanycyte-derived neurogenesis than males, with many of the resulting neurons localizing to the feeding-relevant arcuate nucleus. Female but not male mice show reduced tanycyte-derived arcuate neurogenesis after adult tanycyte Bmal1 deletion and an increased percentage of newborn arcuate neurons take on a feeding-suppressing POMC neuropeptidergic fate. Thereby, skewing of feeding and satiety promoting fates link the weight homeostasis and neurogenesis effects. Together, our data establish tanycyte Bmal1 as a sexually dimorphic regulator of weight homeostasis, likely mediated at least in part by a female-specific neurogenesis effect in the feeding circuitry.

neuroscience↗

bioRxiv2024

The microbiome interacts with the circadian clock and dietary composition to regulate metabolite cycling in the gut

The gut microbiome plays a key role in the maintenance of host metabolic homeostasis and health. Most metabolic processes cycle with a 24-hour rhythm, but the extent to which the microbiome influences metabolite cycling under different conditions, such as variations in dietary composition, remains largely unknown. In this study, we utilized high temporal resolution metabolite profiling of the Drosophila gut to investigate the role of the microbiome in metabolite cycling. We find that the microbiome increases the number of oscillating metabolites despite the previous finding that it dampens transcript cycling in the gut. Time restricted feeding (TF) also promotes metabolite cycling and does so to a larger extent in germ-free flies, thereby increasing cycling in these flies to levels comparable to those in microbiome containing flies. Enhancement of cycling by the microbiome depends upon a circadian clock, which also maintains phase in the face of changes in the microbiome. Interestingly, a high-protein diet increases microbiome- dependent metabolite cycling, while a high sugar diet suppresses it. Gene Ontology identifies amino acid metabolism as the metabolic pathway most affected by changes in the gut microbiome, the circadian clock and timed feeding, suggesting that it is subject to regulation by multiple inputs. Collectively, our observations highlight a key role of the gut microbiome in host metabolite cycling, and reveal a complex interaction with internal and external factors.

microbiology↗

bioRxiv2020

Blocking gephyrin phosphorylation or microglia BDNF signaling prevents synapse loss and reduces infarct volume after ischemia

Microglia interact with neurons to facilitate synapse plasticity; however, signal transducers between microglia and neuron remain unknown. Here, using in vitro organotypic hippocampal slice cultures and transient MCAO in genetically-engineered mice in vivo, we report that at 24 h post-ischemia microglia release BDNF to downregulate glutamatergic and GABAergic synapses within the peri-infarct area. Analysis of the CA1 hippocampal formation in vitro shows that proBDNF and mBDNF downregulate glutamatergic dendritic spines and gephyrin scaffold stability through p75NTR and TrkB receptors respectively. Post-MCAO, we report that in the peri- infarct area and in the corresponding contralateral hemisphere similar neuroplasticity occur through microglia activation and gephyrin phosphorylation at Ser268, Ser270 in vivo. Targeted deletion of the Bdnf gene in microglia or GphnS268A/S270A (phospho-null) point-mutations protect against ischemic brain damage, neuroinflamation and synapse downregulation normally seen post-MCAO. Collectively, we report that gephyrin phosphorylation and microglia derived BDNF faciliate synapse plasticity after transient ischemia.

neuroscience↗