Biology subjects

Hanna, C.

Publications and source records attributed to Hanna, C..

5 recordsLinked to original sources

bioRxiv2025

Vascular transcriptional and metabolic changes precede progressive intra-renal microvascular rarefaction in autosomal dominant polycystic kidney disease

BackgroundThe mechanisms contributing to progressive kidney damage in autosomal dominant polycystic kidney disease (ADPKD) remain unclear. Renal microvascular (MV) rarefaction plays an important role in kidney disease, but its natural history, underlying mechanisms, and contributions to renal disease progression in ADPKD remain unknown. We hypothesized that intrarenal MV rarefaction is present early on and is preceded by vascular transcriptional and metabolic changes. MethodsPkd1RC/RC and WT mice (n=16 each) were studied at 1, 6, and 12 months. Total kidney volume (TKV) was measured in vivo (MRI), whereas renal MV architecture (3D-micro-CT), capillary density, perivascular fibrosis, and histomorphometric parameters were assessed ex vivo. In randomly selected Pkd1RC/RC and WT kidneys (n=5, each/timepoint), mRNA-sequencing was performed to identify differentially expressed vasculature-related genes (DEGs). Next, in young individuals with ADPKD and matched controls (n=10 each), plasma cellular energy metabolites were determined (LC-MS/MS), validated in an extended cohort (n=32 and n=16, respectively), and correlated with markers of disease severity and progression. Gene-metabolite interaction networks were generated to integrate DEGs in Pkd1RC/RC at 1 month with metabolites dysregulated in individuals with ADPKD. ResultsRenal MV density was preserved at 1 month but progressively decreased at 6 and 12 months, associated with capillary loss and perivascular fibrosis. A total of 110, 48, and 201 DEGs were identified at 1, 6, and 12 months, respectively. Plasma gamma-aminobutyric acid (GABA) and homocysteine (Hcy) levels were higher in individuals with ADPKD versus controls, interacted with DEGs implicated in inflammatory and innate immune response and Hcy metabolism, and correlated with TKV and renal blood flow. ConclusionsOur data demonstrates that intrarenal MV abnormalities present early in ADPKD and are preceded by vascular transcriptional and metabolic changes. The renal microcirculation may constitute an important therapeutic target in ADPKD, and its underlying biomarkers may serve to monitor its progression. TRANSLATIONAL STATEMENTWe provide the first longitudinal and most comprehensive analysis of the intrarenal microvascular network in a slowly progressive orthologous model of ADPKD and integrate the findings with studies in a young cohort of ADPKD individuals. Our integrated preclinical and clinical data identify vasculature-related pathways that could be targeted for therapeutic interventions and contribute promising, noninvasive biomarkers in patients with ADPKD. Furthermore, because alterations of the intrarenal microcirculation may affect drug delivery, a better understanding of its longitudinal changes may aid in treatment management.

physiology↗

bioRxiv2024

A common phthalate replacement disrupts ovarian function in young adult mice

Di-2-ethylhexyl terephthalate (DEHTP) is a replacement for its structural isomer di-2-ethylhexyl phthalate (DEHP), a known endocrine disrupting chemical and ovarian toxicant. DEHTP is used as a plasticizer in polyvinyl chloride products and its metabolites are increasingly found in biomonitoring studies at levels similar to phthalates. However, little is known about the effects of DEHTP on the ovary. In this research, we tested the hypothesis that DEHTP is an ovarian toxicant and likely endocrine disrupting chemical like its isomer DEHP. The impact of environmentally relevant exposure to DEHTP and/or its metabolite mono-2-ethylhexyl terephthalate (MEHTP) on the mouse ovary was investigated in vivo and in vitro. For the in vivo studies, young adult CD-1 mice were orally dosed with vehicle, 10 {micro}g/kg, 100 {micro}g/kg, or 100 mg/kg of DEHTP for 10 days. For the in vitro studies, isolated untreated ovarian follicles were exposed to vehicle, 0.1, 1, 10, or 100 {micro}g/mL of DEHTP or MEHTP. Follicle counts, hormone levels, and gene expression of steroidogenic enzymes, cell cycle regulators, and apoptosis factors were analyzed. In vivo, DEHTP exposure increased primordial follicle counts at 100 {micro}g/kg and 100 mg/kg and decreased primary follicle counts at 100 mg/kg compared to control. DEHTP exposure also decreased expression of cell cycle regulators and apoptotic factors compared to control. In vitro, follicle growth was reduced by 1 {micro}g/mL DEHTP and 1, 10, and 100 {micro}g/mL MEHTP compared to controls, and expression of the cell cycle regulator Cdkn2b was increased. Steroid hormone levels and steroidogenic enzyme gene expression trended toward decreases in vivo, whereas progesterone was significantly increased by exposure to 100 {micro}g/mL MEHTP in vitro. Overall, these results suggest that DEHTP and MEHTP may be ovarian toxicants at low doses and should be subjected to further scrutiny for reproductive toxicity due to their similar structures to phthalates.

pharmacology and toxicology↗

bioRxiv2023

Medial Prefrontal Cortex Serotonin Input Regulates Cognitive Flexibility in Mice

The medial prefrontal cortex (mPFC) regulates cognitive flexibility and emotional behavior. Neurons that release serotonin project to the mPFC, and serotonergic drugs influence emotion and cognition. Yet, the specific roles of endogenous serotonin release in the mPFC on neurophysiology and behavior are unknown. We show that axonal serotonin release in the mPFC directly inhibits the major mPFC output neurons. In serotonergic neurons projecting from the dorsal raphe to the mPFC, we find endogenous activity signatures pre-reward retrieval and at reward retrieval during a cognitive flexibility task. In vivo optogenetic activation of this pathway during pre-reward retrieval selectively improved extradimensional rule shift performance while inhibition impaired it, demonstrating sufficiency and necessity for mPFC serotonin release in cognitive flexibility. Locomotor activity and anxiety-like behavior were not affected by either optogenetic manipulation. Collectively, our data reveal a powerful and specific modulatory role of endogenous serotonin release from dorsal raphe-to-mPFC projecting neurons in cognitive flexibility.

neuroscience↗

bioRxiv2021

Cochlear organoids reveal epigenetic and transcriptional programs of postnatal hair cell differentiation from supporting cells

We explored the transcriptional and epigenetic programs underlying the differentiation of hair cells from postnatal progenitor cells in cochlear organoids. Heterogeneity in the cells including cells with the transcriptional signatures of mature hair cells allowed a full picture of possible cell fates. Construction of trajectories identified Lgr5+ cells as progenitors for hair cells and the genomic data revealed gene regulatory networks leading to hair cells. We validated these networks, demonstrating dynamic changes both in expression and predicted binding sites of these transcription factors during organoid differentiation. We identified known regulators of hair cell development, Atoh1, Pou4f3, and Gfi1, and predicted novel regulatory factors, Tcf4, an E-protein and heterodimerization partner of Atoh1, and Ddit3, a CCAAT/enhancer-binding protein (C/EBP) that represses Hes1 and activates transcription of Wnt signaling-related genes. Deciphering the signals for hair cell regeneration from mammalian cochlear supporting cells reveals candidates for HC regeneration which is limited in the adult.

developmental biology↗

bioRxiv2019

Single cell multi-omics profiling reveals a hierarchical epigenetic landscape during mammalian germ layer specification

Formation of the three primary germ layers during gastrulation is an essential step in the establishment of the vertebrate body plan. Recent studies employing single cell RNA-sequencing have identified major transcriptional changes associated with germ layer specification. Global epigenetic reprogramming accompanies these changes, but the role of the epigenome in regulating early cell fate choice remains unresolved, and the coordination between different epigenetic layers is unclear. Here we describe the first single cell triple-omics map of chromatin accessibility, DNA methylation and RNA expression during the exit from pluripotency and the onset of gastrulation in mouse embryos. We find dynamic dependencies between the different molecular layers, with evidence for distinct modes of epigenetic regulation. The initial exit from pluripotency coincides with the establishment of a global repressive epigenetic landscape, followed by the emergence of local lineage-specific epigenetic patterns during gastrulation. Notably, cells committed to mesoderm and endoderm undergo widespread coordinated epigenetic rearrangements, driven by loss of methylation in enhancer marks and a concomitant increase of chromatin accessibility. In striking contrast, the epigenetic landscape of ectodermal cells is already established in the early epiblast. Hence, regulatory elements associated with each germ layer are either epigenetically primed or epigenetically remodelled prior to overt cell fate decisions during gastrulation, providing the molecular logic for a hierarchical emergence of the primary germ layers.\n\nHighlightsO_LIFirst map of mouse gastrulation using comprehensive single cell triple-omic analysis.\nC_LIO_LIExit from pluripotency is associated with a global repressive epigenetic landscape, driven by a sharp gain of DNA methylation and a gradual decrease of chromatin accessibility.\nC_LIO_LIDNA methylation and chromatin accessibility changes in enhancers, but not in promoters, are associated with germ layer formation.\nC_LIO_LIMesoderm and endoderm enhancers become open and demethylated upon lineage commitment.\nC_LIO_LIEctoderm enhancers are primed in the early epiblast and protected from the global repressive dynamics, supporting a default model of ectoderm commitment in vivo.\nC_LI

developmental biology↗