title: Irisin and Myonectin Regulation in the Insulin Resistant Muscle: Implications to Adipose Tissue: Muscle Crosstalk.
abstract: Myokines are peptides produced and secreted by the skeletal muscle, with autocrine, paracrine, and endocrine actions. Many of them are overexpressed during physical exercise and appear to contribute to the benefits of exercise to metabolic homeostasis. Irisin, resulting from the cleavage of the membrane protein FNDC5, was shown to induce adipocyte browning, with increased lipid oxidation and thermogenesis. Myonectin was only recently discovered and initial studies revealed a role in fatty acid uptake and oxidation in adipose tissue and liver. However, the mechanisms of their regulation by exercise are not entirely established. Impaired secretion and action of myokines, such as irisin and myonectin, may have a role in the establishment of insulin resistance. On the other hand, several studies have shown that insulin resistance in the skeletal muscle may change myokines expression and secretion. This may have consequences on lipid and glucose metabolism in adipose tissue and lead to a vicious cycle between impaired myokines production and insulin resistance. This review summarizes the current knowledge about the influence of skeletal muscle insulin resistance on the secretion of irisin and myonectin, as well as its impact on adipose tissue metabolism.
authors.affiliation: Laboratory of Physiology, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal.
authors.forename: Luis
authors.initials: L
authors.lastname: Gamas
authors.affiliation: Laboratory of Physiology, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal ; Department of Complementary Sciences, Coimbra Health School (ESTeSC), Instituto Politécnico de Coimbra, 3040 Coimbra, Portugal.
authors.forename: Paulo
authors.identifier: 0000-0002-3422-290X
authors.initials: P
authors.lastname: Matafome
authors.affiliation: Laboratory of Physiology, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal.
authors.forename: Raquel
authors.initials: R
authors.lastname: Seiça
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D002450:Cell Communication / Q000502:physiology; D003094:Collagen / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism; D015444:Exercise / Q000502:physiology; D005353:Fibronectins / Q000378:metabolism*; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D018482:Muscle, Skeletal / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism
chemical_list: C487851:C1QTNF5 protein, human; C577593:FNDC5 protein, human; D005353:Fibronectins; D003094:Collagen