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    Last Name

    Jack L Leonard PhD

    InstitutionUniversity of Massachusetts Medical School
    DepartmentMicrobiology and Physiological Systems
    AddressUniversity of Massachusetts Medical School
    55 Lake Avenue North
    Worcester MA 01655
      Other Positions
      InstitutionUMMS - School of Medicine

      InstitutionUMMS - Graduate School of Biomedical Sciences
      DepartmentInterdisciplinary Graduate Program

      InstitutionUMMS - Graduate School of Biomedical Sciences


        Academic Background

        B.A., California State University-Fresno;
        Ph.D., University of California-Berkeley, 1976.



        Cellular and Molecular Events that Mediate Thyroid Hormone Action in the Brain

        The focus of this laboratory is the characterization of cellular and molecular events that mediate thyroidhormone action in the brain. Current studies include: cloning and sequencing of the plasma membrane-bound enzyme that bioactivates thyroid hormone; determination of the subunit structure and physiochemical properties of the enzyme polypeptide; characterization of the internalization, sorting and degradation pathway(s) of short-lived membrane proteins in the brain; sequencing of a 55 kDa actin-binding protein whose interactions with actin are hormonally regulated; characterization of the isotypes of erb-a gene products present in cultured cerebrocortical astrocytes; identification of cyclic nucleotide-induced gene products in cultured glial cells using substraction cloning; and determination of the developmental programming of cytoskeletal and integrin gene products in cultured fetal brain cells.

        See our research movie.


        This is a GFP expressing neuron.

        Rotation Projects

        Potential Rotation Projects

        1. Real-time imaging of synaptic vesicle recycling will be done using cultured cerebellar granule neurons, dynamic confocal microscopy, vesicle specific fluorescent dyes, a cohort of GFP-tagged SV marker proteins. The student will learn contemporary techniques in cell and molecular neurobiology.

        2. In vitro propagated cerebellar progenitor cells isolated from a family of thyroid hormone receptor mutants will be implanted into normal neonatal mice and the developmental fate of the implanted cells characterized. The student will learn immunocytochemistry, FACS analysis, and transcript profiling using Affymetrix chip technology.

        selected publications
        List All   |   Timeline
        1. Cheng SY, Leonard JL, Davis PJ. Molecular aspects of thyroid hormone actions. Endocr Rev. 2010 Apr; 31(2):139-70.
          View in: PubMed
        2. Farwell AP, Leonard JL. Effect of methyl iodide on deiodinase activity. Inhal Toxicol. 2009 May; 21(6):497-504.
          View in: PubMed
        3. Leonard JL. Non-genomic actions of thyroid hormone in brain development. Steroids. 2008 Oct; 73(9-10):1008-12.
          View in: PubMed
        4. Davis PJ, Leonard JL, Davis FB. Mechanisms of nongenomic actions of thyroid hormone. Front Neuroendocrinol. 2008 May; 29(2):211-8.
          View in: PubMed
        5. Simpson GI, Leonard DM, Leonard JL. Identification of the key residues responsible for the assembly of selenodeiodinases. J Biol Chem. 2006 May 26; 281(21):14615-21.
          View in: PubMed
        6. Farwell AP, Dubord-Tomasetti SA, Pietrzykowski AZ, Leonard JL. Dynamic nongenomic actions of thyroid hormone in the developing rat brain. Endocrinology. 2006 May; 147(5):2567-74.
          View in: PubMed
        7. Alkemade A, Friesema EC, Unmehopa UA, Fabriek BO, Kuiper GG, Leonard JL, Wiersinga WM, Swaab DF, Visser TJ, Fliers E. Neuroanatomical pathways for thyroid hormone feedback in the human hypothalamus. J Clin Endocrinol Metab. 2005 Jul; 90(7):4322-34.
          View in: PubMed
        8. Leonard JL, Simpson G, Leonard DM. Characterization of the protein dimerization domain responsible for assembly of functional selenodeiodinases. J Biol Chem. 2005 Mar 25; 280(12):11093-100.
          View in: PubMed
        9. Farwell AP, Dubord-Tomasetti SA, Pietrzykowski AZ, Stachelek SJ, Leonard JL. Regulation of cerebellar neuronal migration and neurite outgrowth by thyroxine and 3,3',5'-triiodothyronine. Brain Res Dev Brain Res. 2005 Jan 1; 154(1):121-35.
          View in: PubMed
        10. Dobson JG, Fray J, Leonard JL, Pratt RE. Molecular mechanisms of reduced beta-adrenergic signaling in the aged heart as revealed by genomic profiling. Physiol Genomics. 2003 Oct 17; 15(2):142-7.
          View in: PubMed
        11. Diano S, Leonard JL, Meli R, Esposito E, Schiavo L. Hypothalamic type II iodothyronine deiodinase: a light and electron microscopic study. Brain Res. 2003 Jun 20; 976(1):130-4.
          View in: PubMed
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