Nutrition and Metabolism Graduate Program

    College of Agricultural & Life Sciences

    UNIVERSITY of WISCONSIN-MADISON UW-MADISON

    Judith Simcox

    Associate Professor of Biochemistry

    Transcriptional regulation of nutrient responsive pathways in thermogenesis

    jsimcox@wisc.edu

    371B HF DeLuca Biochemistry Laboratories
    433 Babcock Drive

    Type: ,
    Department:

    Education

    • B.S., Carroll College
    • Ph.D., University of Utah
    • Postdoctoral, University of Utah

    As a postdoctoral fellow, I discovered that acylcarnitines are necessary for maintaining body temperature during cold exposure. Cold exposure triggers the release of free fatty acids from white adipocytes, which then go to the liver to where they are substrates for acylcarnitine production and secretion into circulation. These excess acylcarnitines are then taken up by the brown adipose tissue and used to fuel thermogenesis.

    The Simcox laboratory focuses on two unanswered questions:
    1) How are liver-produced lipids taken up and metabolized in brown adipocytes?
    Brown adipocytes increase uptake of circulating lipids 12-fold during cold exposure, but the contribution of the various lipid species to thermogenesis remains elusive. We will use heavy isotope and fluorescently labeled lipids to identify lipid importers, assess metabolic pathways of uptake, and characterize the functional importance of various lipid species in isolated brown adipocytes.

    2) How is hepatic lipid processing regulated in cold exposure?
    Hepatic lipid processing is required for mice to maintain their body temperature in response to cold exposure. In untargeted lipidomic analysis we identified several hundred hepatic lipids that are altered in cold exposure and correlate with changes in circulating lipids. We will functionally characterize the role of these lipids in cold exposure and identify the transcriptional programs that regulate their production and clearance.

    Click here to view graphical abstract

    • HHMI Freeman Hrabowski Scholar
    • Distinguished Faculty and Staff Postdoc Mentoring Award, UW-Madison (2025)
    • ASBMB Walter A Shaw Young Investigator Award in Lipid Research (2024)
    • Distinguished Role Model in Life Science, Northwestern University (2023)
    • JDRF Diversifying Diabetes Research Talent in Academica Award (2022)
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