Biology subjects

Welch, E.

Publications and source records attributed to Welch, E..

3 recordsLinked to original sources

bioRxiv2026

Aberrant microglial responses shape hypothalamic circuits in anorexia nervosa

Multimodal data indicates that microglia contribute to the pathophysiology of anorexia nervosa (AN). Here, we investigated microglial modulation of hypothalamic circuits, key regulators of energy balance, hypothesising an implication in the prolonged starvation and low body weight of AN. First, we generated microglia as well as hypothalamic and cortical neurons from patient-derived induced pluripotent stem cells (iPSCs) to discover upregulation of synapse-related genes in hypothalamic neurons, reduced microglial uptake of hypothalamic synaptic structures, and a microglial unresponsivness to the satiety hormone glucagon-like peptide-1. In an AN animal model (anx/anx mouse), spatial transcriptomics indicated hypothalamic microglial activation and disrupted microglia-synapse signaling. Despite an increased microglia density in both the arcuate nucleus (ARC) and the dorsomedial hypothalamus region (DMH), microglia displayed a decreased per cell uptake of synaptic material in Arc. Together, these data suggest that microglial responses shape hypothalamic circuits with possible implications for the maintained negative energy balance of AN.

neuroscience↗

bioRxiv2024

Cortico-hippocampal interactions underlie schema-supported memory encoding in older adults

Although episodic memory is typically impaired in older adults (OAs) compared to young adults (YAs), this deficit is attenuated when OAs can leverage their rich semantic knowledge, such as their knowledge of schemas. Memory is better for items consistent with pre-existing schemas and this effect is larger in OAs. Neuroimaging studies have associated schema use with the ventromedial prefrontal cortex (vmPFC) and hippocampus (HPC), but most of this research has been limited to YAs. This fMRI study investigated the neural mechanisms underlying how schemas boost episodic memory in OAs. Participants encoded scene-object pairs with varying congruency, and memory for the objects was tested the following day. Congruency with schemas enhanced object memory for YAs and, more substantially, for OAs. FMRI analyses examined how cortical modulation of HPC predicted subsequent memory. Congruency-related vmPFC modulation of left HPC enhanced subsequent memory in both age groups, while congruency-related modulation from angular gyrus (AG) boosted subsequent memory only in OAs. Individual differences in cortico-hippocampal modulations indicated that OAs preferentially used their semantic knowledge to facilitate encoding via an AG-HPC interaction, suggesting a compensatory mechanism. Collectively, our findings illustrate age-related differences in how schemas influence episodic memory encoding via distinct routes of cortico-hippocampal interactions.

neuroscience↗

bioRxiv2018

A new in vitro assay measuring direct interaction of nonsense suppressors with the eukaryotic protein synthesis machinery

Nonsense suppressors (NonSups) induce \"readthrough\", i.e., the selection of near cognate tRNAs at premature termination codons and insertion of the corresponding amino acid into nascent polypeptide. Prior readthrough measurements utilized contexts in which NonSups can promote readthrough directly, by binding to one or more of the components of the protein synthesis machinery, or indirectly, by several other mechanisms. Here we utilize a new, highly-purified in vitro assay to measure exclusively direct nonsense suppressor-induced readthrough. Of 16 NonSups tested, 12 display direct readthrough, with results suggesting that such NonSups act by at least two different mechanisms. In preliminary work we demonstrate the potential of single molecule fluorescence energy transfer measurements to elucidate mechanisms of NonSup-induced direct readthrough, which will aid efforts to identify NonSups having improved clinical efficacy.\n\nTable of Contents artwork\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC=\"FIGDIR/small/330506_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (18K):\norg.highwire.dtl.DTLVardef@a548dborg.highwire.dtl.DTLVardef@15237bcorg.highwire.dtl.DTLVardef@c93d3forg.highwire.dtl.DTLVardef@1d40e2c_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗