Positions

Overview

  • Dr. Peggy Biga is a broadly trained comparative endocrine physiologist, with primary research interests focusing on the mechanisms regulating growth patterns in animals. Her research questions revolve around what molecular and epigenetic mechanisms regulate skeletal muscle proliferation, differentiation, and atrophy. She uses comparative biology to understand the plasticity of regulatory mechanisms and how they translate to variability in overall organismal growth.

    For example, most, and arguably all, terrestrial mammals reach a growth plateau around the time they reach sexual maturity which is characterized by a lack of nascent (or new) muscle fiber development post-embryonic growth. Alternatively, many aquatic vertebrates exhibit an opposing growth paradigm where no true growth plateau is reached, and skeletal muscle continues to growth through the addition of nascent muscle fibers throughout their life. The main focus of Dr. Biga’s lab for many years has been to identify molecular pathways and mechanisms that regulate the ability of some animals to continually grow (by adding NEW muscle fibers) throughout their lives. As a post-doctoral scientist, Dr. Biga identified and verified a comparative model system that can be used to ask these questions. She demonstrated that two closely related fish species, the zebrafish and giant danio, exhibit differential growth paradigms. The zebrafish, a commonly used model organism, exhibits a growth pattern that closely mirrors what is seen in human muscle growth, where muscle growth is accomplished post-birth/hatch with little to no addition of new muscle fibers, but instead through the enlargement of pre-existing fibers. Alternatively, a close relative to the zebrafish, the giant danio, exhibit continual addition of nascent muscle fibers throughout their lives. By juxtaposing the growth of these two fish species, Dr. Biga has identified transcription factors and myogenic regulatory factors that are differentially regulated between the growth types.

    Dr. Biga’s research interests also focus on the endocrine regulation of growth biology, with particular focus on the GH-IGF system in relation to myostatin control of cell proliferation, cell differentiation, and energy metabolism. Myostatin is a negative regulator of muscle growth, and is known to be sensitive to GH and IGF signaling in muscle tissue. In addition, Dr. Biga has shown that myostatin is also responsive to stress hormones, like cortisol, which is likely to be involved in stress-induced muscle atrophy. Also, Dr. Biga is interested in the direct action GH might have on muscle cells in relation to cell proliferation and differentiation, and cellular respiration. This work is primarily conducted using the rainbow trout as a model, as this fish species is an important species for the US aquaculture industry.

    In addition, Dr. Biga’s research also focuses on how diet influences the mechanisms that regulation growth and metabolism. Her lab researches questions related to how individual nutrients influence growth and metabolic physiology, and how these nutrients alter the epigenome to regulate changes in physiology. Within this area of research, Dr. Biga has demonstrated that amino acid (ex., methionine) restriction alters muscle cell proliferation and induces autophagy in vitro. In addition, Dr. Biga’s lab has also demonstrated that methionine restriction affects glucose metabolism that is likely regulated through changes in miRNA expression in a tissue-specific manner. On the other side of the diet-epigenetic interaction research focus, Dr. Biga is interested in evaluating how methyl-donor amino acid supplementation can affect growth physiology through maternal imprinting.

    Dr. Biga participates in several collaborations with scientists in France, Canada, and the US on research projects that focus on how endocrinology, molecular biology, epigenetics, and physiology interact to regulate growth physiology.
  • Selected Publications

    Academic Article

    Year Title Altmetric
    2019 Glucose regulates protein turnover and growth-related mechanisms in rainbow trout myogenic precursor cellsComparative Biochemistry and Physiology - Part A: Molecular and Integrative Physiology.  232:91-97. 2019
    2018 Dietary methionine restriction: Effects on glucose tolerance, lipid content and micro-RNA composition in the muscle of rainbow troutComparative Biochemistry and Physiology - Part C: Toxicology and Pharmacology.  208:47-52. 2018
    2018 The validation of a sensitive, non-toxic in vivo metabolic assay applicable across zebrafish life stagesComparative Biochemistry and Physiology - Part C: Toxicology and Pharmacology.  208:29-37. 2018
    2018 Physiological and molecular mechanisms of methionine restrictionFrontiers in Endocrinology.  9. 2018
    2018 A comparative evaluation of crowding stress on muscle HSP90 and myostatin expression in salmonidsAquaculture.  483:141-148. 2018
    2017 Distribution of H3K27me3, H3K9me3, and H3K4me3 along autophagy-related genes highly expressed in starved zebrafish myotubesBiology Open.  6:1720-1725. 2017
    2017 MiR-210 expression is associated with methionine-induced differentiation of trout satellite cellsJournal of Experimental Biology.  220:2932-2938. 2017
    2016 A comparative examination of cortisol effects on muscle myostatin and HSP90 gene expression in salmonidsGeneral and Comparative Endocrinology.  237:19-26. 2016
    2015 Evolutionary history and epigenetic regulation of the three paralogous pax7 genes in rainbow troutCell and Tissue Research.  359:715-727. 2015
    2014 Evolutionary history and epigenetic regulation of the three paralogous pax7 genes in rainbow troutCell and Tissue Research2014
    2014 Aging and energetics' 'Top 40' future research opportunities 2010-2013F1000Research.  3. 2014
    2014 Overcompensation of circulating and local insulin-like growth factor-1 during catch-up growth in hybrid striped bass (Morone chrysops×Morone saxatilis) following temperature and feeding manipulationsAquaculture.  428-429:174-183. 2014
    2014 Preparation of primary myogenic precursor cell/myoblast cultures from basal vertebrate lineagesJournal of Visualized Experiments2014
    2014 Physiological differences between lean and siscowet lake trout morphotypes: Are these metabolotypes?Canadian Journal of Fisheries and Aquatic Sciences.  71:427-435. 2014
    2014 High-fat diet reduces local myostatin-1 paralog expression and alters skeletal muscle lipid content in rainbow trout, Oncorhynchus mykissFish Physiology and Biochemistry.  40:875-886. 2014
    2014 The effects of exogenous cortisol on myostatin transcription in rainbow trout, Oncorhynchus mykissComparative Biochemistry and Physiology - Part A: Molecular and Integrative Physiology.  175:57-63. 2014
    2013 Revisiting the paradigm of myostatin in vertebrates: Insights from fishesGeneral and Comparative Endocrinology.  194:45-54. 2013
    2013 Sarcopenia and piscines: The case for indeterminate-growing fish as unique genetic model organisms in aging and longevity researchFrontiers in Genetics.  4. 2013
    2013 Gelatinases impart susceptibility to high-fat diet-induced obesity in miceJournal of Nutritional Biochemistry.  24:1462-1468. 2013
    2013 In vitro indeterminate teleost myogenesis appears to be dependent on Pax3In Vitro Cellular and Developmental Biology - Animal.  49:371-385. 2013
    2013 High-fat diet reduces local myostatin-1 paralog expression and alters skeletal muscle lipid content in rainbow trout, Oncorhynchus mykissFish Physiology and Biochemistry.  1-12. 2013
    2013 Inbred strains of zebrafish exhibit variation in growth performance and myostatin expression following fastingComparative Biochemistry and Physiology - Part A: Molecular and Integrative Physiology.  164:1-9. 2013
    2011 Development of yellow perch (Perca flavescens) broodstocks: Initial characterization of growth and quality traits following grow-out of different stocksAquaculture.  317:58-66. 2011
    2011 Characterization of Giant Danio and Rainbow Trout Primary Myoblast Culture SystemsAmerican Zoologist.  51:E190-E190. 2011
    2011 Expression of Akirin Isoforms During Muscle Regeneration in Response to Muscle Injury in Rainbow Trout (Oncorhynchus mykiss)American Zoologist.  51:E166-E166. 2011
    2011 Expression of Myostatin and Akirin Isoforms in Mice (Mus Musculus) fed a High Fat DietAmerican Zoologist.  51:E174-E174. 2011
    2011 Tissue distribution of akirin genes in several vertebrate species, including fish and rodents.American Zoologist.  51:E174-E174. 2011
    2010 Myostatin expression, lymphocyte population, and potential cytokine production correlate with predisposition to high-fat diet induced obesity in micePLoS ONE.  5:1-13. 2010
    2010 Characterization of Novel Teleost Systems for Studying Muscle GrowthAmerican Zoologist.  50:E231-E231. 2010
    2009 Growth hormone differentially regulates growth and growth-related gene expression in closely related fish speciesComparative Biochemistry and Physiology - Part A: Molecular and Integrative Physiology.  154:465-473. 2009
    2009 A novel down-stream target of myostatin: important in muscle growth and regulation?American Zoologist.  49:E204-E204. 2009
    2009 Does myostatin play a regulatory role outside of muscle growth and metabolism?American Zoologist.  49:E15-E15. 2009
    2009 Role of Matrix metalloproteinases in activating myostatin in the skeletal muscle in response to high fat diet induced diabesityAmerican Zoologist.  49:E285-E285. 2009
    2006 Zebrafish and giant danio as models for muscle growth: Determinate vs. indeterminate growth as determined by morphometric analysisAJP - Regulatory, Integrative and Comparative Physiology.  291. 2006
    2006 Comparative analysis of growth-related genes between morphologically and genetically different lake trout (Salvelinus namaycush) phenotypes from Lake SuperiorJournal of Experimental Zoology Part A: Comparative Experimental Biology.  305A:112-112. 2006
    2005 The isolation, characterization, and expression of a novel GDF11 gene and a second myostatin form in zebrafish, Danio rerioComparative Biochemistry and Physiology - Part B: Biochemistry and Molecular Biology.  141:218-230. 2005
    2005 Bovine growth hormone treatment increased IGF-I in circulation and induced the production of a specific immune response in rainbow trout (Oncorhynchus mykiss)Aquaculture.  246:437-445. 2005
    2004 Growth hormone differentially regulates muscle myostatin1 and -2 and increases circulating cortisol in rainbow trout (Oncorhynchus mykiss)General and Comparative Endocrinology.  138:32-41. 2004
    2004 The effects of recombinant bovine somatotropin (rbST) on tissue IGF-I, IGF-I receptor, and GH mRNA levels in rainbow trout, Oncorhynchus mykissGeneral and Comparative Endocrinology.  135:324-333. 2004
    2003 Growth hormone differentially regulates muscle myostatin-I and II and increases circulating cortisol in rainbow trout (Oncorhynchus mykiss).American Zoologist.  43:928-928. 2003
    2003 Plasma insulin-like growth factor-I concentrations in yearling chinook salmon (Oncorhynchus tshawytscha) migrating from the Snake River Basin, USAFish Physiology and Biochemistry.  29:57-66. 2003

    Chapter

    Year Title Altmetric
    2009 Muscle Regulation.  279-313. 2009

    Research Overview

  • The overall goal of my research program is to identify mechanisms regulating organismal growth potential, with specific interest on mechanisms allowing for continual growth throughout an organism’s life (indeterminate growth). My lab addresses this goal using many approaches that range from cellular to organismal: molecular biology, cell biology, endocrinology, physiology, and morphology. Generally, my lab utilizes piscine species as model organisms because they offer diverse growth potentials and serve as excellent comparative platforms. The following projects are currently active and are being primarily driven by graduate and undergraduate students in my lab:

    Epigenetic regulation of myogenesis is regulated by specific nutrients, namely amino acids.

    Working closely with Dr. Jean-Charles Gabillard (INRA, Rennes, France) and Dr. Iban Seiliez (INRA, St. Pee, France) we have characterized the histone methylation profile related to pax7 and myogenin expression during in vitro myogenesis in Rainbow trout, an indeterminate growing fish. We recently also demonstrated that methionine depletion specifically alters this epigenetic profile, as well as reverts myoblasts to the quiescent state, suggesting a role of histone methylation in myogenic progression regulation. This quiescence appears to be reversible with addition of methionine. We are currently investigating the role of microRNAs as part of this mechanism as well.

    Nutritional state regulates atrophy/hypertrophy balance in myogenic cells in vitro.

    Working closely with Dr. Jean-Charles Gabillard (INRA, Rennes, France) and Dr. Iban Seiliez (INRA, St. Pee, France) we have characterized a novel in vitro model of amino acid depletion induced autophagy using zebrafish as a model organism. Using an amino acid depleted media, we can induce autophagy without apoptosis during myogenesis in vitro. We have characterized the histone methylation profiles affected by this cell phenotype switch and identified Atg4b, p62/sqstrm1, and lc3b as tightly regulated by starvation during the onset of autophagy.

    Maternal nutritional transfer regulates growth via epigenetic mechanisms.

    Working closely with Dr. Beth Cleveland (USDA, ARS, Leetown, WV USA) we have demonstrated that supplementing maternal broodstock diets with choline results in enhanced offspring growth performance. Also, we recently demonstrated that choline supplemented diet intake results in increased levels of choline into the pre-fertilized eggs. We hypothesized that maternal dietary intake regulates growth performance through changes in epigenetic mechanisms regulating growth. Choline serves as a methyl donor, and we are currently evaluating the role of choline supplementation on methylome changes.

    The role of paired box transcription factors (Pax) in regulating myogenic stem cell populations.

    My lab has recently demonstrated that indeterminate growing fish species exhibit a unique a pax3 expression profile in adult myogenic progenitor cells (MPCs; muscle stem cells) compared to determinate growing organisms. MPCs from adult indeterminate growing danios are pax3+/+, while determinate growing danios’ MPCs are pax3-/- (similar to adult mammalian MPCs) suggesting a potential role of pax3 in regulate MPC function. We are currently working to empirically test a role of pax3 in MPC function by knocking it down (morpholino and siRNA) in isolated MPCs.

    Myogenic precursor cell contribution to muscle repair across the life-course in indeterminately growing species. Question: Does repair capacity decrease with age in indeterminate growing species?

    We are currently characterizing the muscle repair program in indeterminately growing fish species (trout and danios) to establish a baseline understanding of the cells, genes, and pathways that play key roles in muscle repair in juvenile, sexually mature, and aged organisms. We hypothesize that species with high pax3 expression in MPCs as adults will have an enhanced repair capacity compared to species lacking pax3 expression as adults. Additionally, we will examine the role of growth hormone, IGF-I, IGF-II, and myostatin in muscle repair related to aging decline (or lack thereof).

    The role of Teneurin C-terminal Associated Peptide (TCAP) in muscle function and metabolism during aging.

    In collaboration with Dr. David Lovejoy (University of Toronto, Canada) and his PhD student Andrea D’Aquila we are investigating the conserved function of TCAP in muscle hypertrophy and metabolic control in teleosts. In addition, we have pilot funds from the Nathan Shock Center to examine the role TCAP plays in regulating muscle function decline during aging in the short-lived killifish model. We are also examining the effects of chronic TCAP treatment on zebrafish muscle hypertrophy and metabolic regulation. We will also begin evaluating the role TCAP plays in starvation-induced autophagy in primary myotubes in vitro. This work is specifically and uniquely informative for human muscular repair/regeneration and wasting disorders.

    These research projects cover the general topic of mechanisms regulating muscle growth and repair, the overarching theme of my research program. This work is translatable to human health as mammals lose their ability to adequately repair their muscle tissue with age. In some teleost species, this functional decline in muscle structure and function is not observed and we hypothesize that the mechanisms that allow for continued growth throughout the lives of these organisms plays an important role in delaying muscle senescence (or wasting). In addition, improving adult muscle repair capabilities is extremely important in wound healing. In addition, this work is translatable to production agriculture, as further understanding of mechanisms regulating fish growth, from epigenetics to endocrinology, has direct applicability to the production efficacy to several finfish industries (including rainbow trout).

    Comparative Growth Biology, Developmental Physiology, Diet-Epigenetic Interactions, Skeletal Muscle Growth Regulation, Science Community Outreach, k-12 Science Engagement
  • Teaching Activities

  • BY245 - Fundamental Scientific Invest. (Spring Term 2019) 2019
  • BY495 - Special Topics in Biology (Spring Term 2019) 2019
  • BY695 - Special Topics in Biology I (Spring Term 2019) 2019
  • BY698 - Nonthesis Research (Spring Term 2019) 2019
  • BY795 - Special Topics in Biology I (Spring Term 2019) 2019
  • BY398 - Undergrad Research - RES (Fall Term 2018) 2018
  • BY475 - Comp Developmental Biology (Fall Term 2018) 2018
  • BY675 - Comp Developmental Biology (Fall Term 2018) 2018
  • BY698 - Nonthesis Research (Fall Term 2018) 2018
  • BY798 - Nondissertation Research (Fall Term 2018) 2018
  • BY123 - Introductory Biology I (Summer Term 2018) 2018
  • BY798 - Nondissertation Research (Summer Term 2018) 2018
  • BY799 - Dissertation Research (Summer Term 2018) 2018
  • BY245 - Fundamental Scientific Invest. (Spring Term 2018) 2018
  • BY555 - Prin of Scientific Investig (Spring Term 2018) 2018
  • BY698 - Nonthesis Research (Spring Term 2018) 2018
  • BY798 - Nondissertation Research (Spring Term 2018) 2018
  • BY799 - Dissertation Research (Spring Term 2018) 2018
  • BY123 - Introductory Biology I (Fall Term 2017) 2017
  • BY698 - Nonthesis Research (Fall Term 2017) 2017
  • BY798 - Nondissertation Research (Fall Term 2017) 2017
  • BY799 - Dissertation Research (Fall Term 2017) 2017
  • BY698 - Nonthesis Research (Summer Term 2017) 2017
  • BY798 - Nondissertation Research (Summer Term 2017) 2017
  • BY799 - Dissertation Research (Summer Term 2017) 2017
  • BY398 - Undergrad Research - RES (Spring Term 2017) 2017
  • BY429 - Intro to Evolutionary Process (Spring Term 2017) 2017
  • BY491 - Biology Capstone - Evolution (Spring Term 2017) 2017
  • BY629 - Evolutionary Biology (Spring Term 2017) 2017
  • BY798 - Nondissertation Research (Spring Term 2017) 2017
  • BY398 - Undergrad Research - RES (Fall Term 2016) 2016
  • BY475 - Comp Developmental Biology (Fall Term 2016) 2016
  • BY675 - Comp Developmental Biology (Fall Term 2016) 2016
  • BY798 - Nondissertation Research (Fall Term 2016) 2016
  • BY798 - Nondissertation Research (Summer Term 2016) 2016
  • BY398 - Undergrad Research - RES (Spring Term 2016) 2016
  • BY429 - Intro to Evolutionary Process (Spring Term 2016) 2016
  • BY491 - Biology Capstone - Evolution (Spring Term 2016) 2016
  • BY629 - Evolutionary Biology (Spring Term 2016) 2016
  • BY798 - Nondissertation Research (Spring Term 2016) 2016
  • BY475 - Comp Developmental Biology (Fall Term 2015) 2015
  • BY675 - Comp Developmental Biology (Fall Term 2015) 2015
  • BY123 - Introductory Biology I (Summer Term 2015) 2015
  • BY398 - Undergrad Research - RES (Summer Term 2015) 2015
  • BY798 - Nondissertation Research (Summer Term 2015) 2015
  • BY499 - Biology Seminar (Spring Term 2015) 2015
  • BY798 - Nondissertation Research (Spring Term 2015) 2015
  • BY398 - Undergrad Research - RES (Fall Term 2014) 2014
  • BY475 - Comp Developmental Biology (Fall Term 2014) 2014
  • BY675 - Comp Developmental Biology (Fall Term 2014) 2014
  • BY798 - Nondissertation Research (Fall Term 2014) 2014
  • BY799 - Dissertation Research (Summer Term 2014) 2014
  • BY123 - Introductory Biology I (Spring Term 2014) 2014
  • BY699 - Thesis Research (Spring Term 2014) 2014
  • BY799 - Dissertation Research (Spring Term 2014) 2014
  • BY475 - Comp Developmental Biology (Fall Term 2013) 2013
  • BY675 - Comp Developmental Biology (Fall Term 2013) 2013
  • BY699 - Thesis Research (Fall Term 2013) 2013
  • BY799 - Dissertation Research (Fall Term 2013) 2013
  • BY475 - Mammalian Development (Fall Term 2012) 2012
  • BY675 - Mammalian Embryology (Fall Term 2012) 2012
  • Education And Training

  • Doctor of Philosophy in Biology, University of Idaho 2003
  • Full Name

  • Peggy Biga