# Dissecting the Nutritional Regulation of Feeding Circuits

> **NIH NIH K08** · NORTHWESTERN UNIVERSITY · 2020 · $172,098

## Abstract

PROJECT SUMMARY/ABSTRACT
RESEARCH STRATEGY: Communication between the gut and the brain is essential for energy homeostasis,
but how this communication is represented in the dynamics of hypothalamic feeding circuitry is unknown. Early
studies of the gut-brain axis relied upon indirect measurements of the effects of nutritionally regulated
peripheral signals on feeding circuitry. These studies led to a model in which the activity of key hypothalamic
hunger neurons – AgRP neurons – fluctuates gradually as the animal's nutritional state changes. With the
development of techniques to record the activity of genetically-defined neuronal populations in awake animals,
the dynamics of AgRP neurons were recently observed in vivo for the first time. These studies revealed,
contrary to the prevailing model, that AgRP neurons are inhibited rapidly when an animal sees or smells food,
before it takes a single bite; however, food ingestion is required for maintenance of this inhibition. We have
developed a tool combining in vivo monitoring of AgRP neuron dynamics with intragastric nutrient infusion to
show for the first time that nutrient delivery to the gut, in the absence of the sensory stimuli normally associated
with eating, is sufficient to inhibit AgRP neurons over a time-scale of minutes. This inhibition is independent of
the macronutrient composition of the food but depends upon the number of calories ingested. The goal of this
proposal is to determine the molecular and circuit-based mechanisms by which each macronutrient inhibits
AgRP neurons. This will be accomplished across three aims: to identify the hormonal mediators responsible, to
identify the nutrient sensors involved, and to dissect the pathway by which these signals reach AgRP neurons.
CANDIDATE/ENVIRONMENT: Dr. Lisa Beutler is a senior fellow in the Division of Endocrinology at UCSF.
She recently completed internal medicine residency at UCSF and an MD/PhD at the University of Washington,
where she earned her PhD in Dr. Richard Palmiter's laboratory. She is finishing her fellowship research, which
is the subject of a first-author publication in the journal Neuron, in Dr. Zachary Knight's laboratory at UCSF.
Having gained expertise in in vivo neural recording and advanced rodent surgery, she now seeks to expand
her expertise in the lab to include optical circuit dissection, single-cell resolution calcium imaging, and data
analysis and programming skills prior to obtaining an independent position as an academic physician-scientist.
CAREER DEVELOPMENT: This award will ensure that Dr. Beutler is able to launch her career as an
independent investigator armed with a combination of experimental tools that both position her at the cutting
edge of her field (calcium-based imaging techniques, optogenetics) and set her apart from others in the field
(advanced rodent surgical techniques). Combined with her clinical training in endocrinology, this will make her
uniquely poised to address questions that req...

## Key facts

- **NIH application ID:** 9908071
- **Project number:** 5K08DK118188-04
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **Principal Investigator:** Lisa R Beutler
- **Activity code:** K08 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $172,098
- **Award type:** 5
- **Project period:** 2019-08-01 → 2022-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9908071

## Citation

> US National Institutes of Health, RePORTER application 9908071, Dissecting the Nutritional Regulation of Feeding Circuits (5K08DK118188-04). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/9908071. Licensed CC0.

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