title: Metrnl: a secreted protein with new emerging functions.
abstract: Secreted proteins play critical roles in physiological and pathological processes and can be used as biomarkers and therapies for aging and disease. Metrnl is a novel secreted protein homologous to the neurotrophin Metrn. But this protein, unlike Metrn that is mainly expressed in the brain, shows a relatively wider distribution in the body with high levels of expression in white adipose tissue and barrier tissues. This protein plays important roles in neural development, white adipose browning and insulin sensitization. Based on its expression and distinct functions, this protein is also called Cometin, Subfatin and Interleukin 39, which refer to its neurotrophic effect, adipokine function and the possible action as a cytokine, respectively. The spectrum of Metrnl functions remains to be determined, and the mechanisms of Metrnl action need to be elucidated. In this review, we focus on the discovery, structural characteristics, expression pattern and physiological functions of Metrnl, which will assist in developing this protein as a new therapeutic target or agent.
authors.affiliation: Department of Pharmacology, Second Military Medical University, Shanghai 200433, China.
authors.forename: Si-Li
authors.initials: SL
authors.lastname: Zheng
authors.affiliation: Department of Pharmacology, Second Military Medical University, Shanghai 200433, China.
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Li
authors.affiliation: Department of Pharmacology, Second Military Medical University, Shanghai 200433, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Song
authors.affiliation: Stroke Center & Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai 200433, China.
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Liu
authors.affiliation: Department of Pharmacology, Second Military Medical University, Shanghai 200433, China.|Center of Stroke, Beijing Institute for Brain Disorders, Beijing 100069, China.
authors.forename: Chao-Yu
authors.initials: CY
authors.lastname: Miao
mesh_terms: D054392:Adipokines / Q000235:genetics / Q000378:metabolism*; D002001:Adipose Tissue, Brown / Q000378:metabolism; D052436:Adipose Tissue, White / Q000378:metabolism; D000818:Animals; D006801:Humans; D007333:Insulin Resistance; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009928:Organ Specificity
chemical_list: D054392:Adipokines; D036341:Intercellular Signaling Peptides and Proteins; C502097:METRN protein, human; C000593412:Metrnl protein, human; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins