title: Restoration of testis function in hypogonadotropic hypogonadal mice harboring a misfolded GnRHR mutant by pharmacoperone drug therapy.
abstract: Mutations in receptors, ion channels, and enzymes are frequently recognized by the cellular quality control system as misfolded and retained in the endoplasmic reticulum (ER) or otherwise misrouted. Retention results in loss of function at the normal site of biological activity and disease. Pharmacoperones are target-specific small molecules that diffuse into cells and serve as folding templates that enable mutant proteins to pass the criteria of the quality control system and route to their physiologic site of action. Pharmacoperones of the gonadotropin releasing hormone receptor (GnRHR) have efficacy in cell culture systems, and their cellular and biochemical mechanisms of action are known. Here, we show the efficacy of a pharmacoperone drug in a small animal model, a knock-in mouse, expressing a mutant GnRHR. This recessive mutation (GnRHR E(90)K) causes hypogonadotropic hypogonadism (failed puberty associated with low or apulsatile luteinizing hormone) in both humans and in the mouse model described. We find that pulsatile pharmacoperone therapy restores E(90)K from ER retention to the plasma membrane, concurrently with responsiveness to the endogenous natural ligand, gonadotropin releasing hormone, and an agonist that is specific for the mutant. Spermatogenesis, proteins associated with steroid transport and steroidogenesis, and androgen levels were restored in mutant male mice following pharmacoperone therapy. These results show the efficacy of pharmacoperone therapy in vivo by using physiological, molecular, genetic, endocrine and biochemical markers and optimization of pulsatile administration. We expect that this newly appreciated approach of protein rescue will benefit other disorders sharing pathologies based on misrouting of misfolded protein mutants.
authors: Divisions of Reproductive and Developmental Science and Neuroscience and Comparative Medicine, Oregon National Primate Research Center, Beaverton, OR 97006.
authors: Jo Ann
authors: JA
authors: Janovick
authors: M David
authors: MD
authors: Stewart
authors: Darla
authors: D
authors: Jacob
authors: L D
authors: LD
authors: Martin
authors: Jian Min
authors: JM
authors: Deng
authors: C Allison
authors: CA
authors: Stewart
authors: Ying
authors: Y
authors: Wang
authors: Anda
authors: A
authors: Cornea
authors: Lakshmi
authors: L
authors: Chavali
authors: Suhujey
authors: S
authors: Lopez
authors: Shoukhrat
authors: S
authors: Mitalipov
authors: Eunju
authors: E
authors: Kang
authors: Hyo-Sang
authors: HS
authors: Lee
authors: Pulak R
authors: PR
authors: Manna
authors: Douglas M
authors: DM
authors: Stocco
authors: Richard R
authors: RR
authors: Behringer
authors: P Michael
authors: PM
authors: Conn
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D055879:Gene Knock-In Techniques; D007006:Hypogonadism / Q000188:drug therapy* / Q000235:genetics; D008297:Male; D051379:Mice; D018832:Molecular Chaperones / Q000494:pharmacology* / Q000627:therapeutic use; D009154:Mutation / Q000235:genetics; D017510:Protein Folding / Q000187:drug effects*; D057165:Proteostasis Deficiencies / Q000235:genetics*; D011966:Receptors, LHRH / Q000235:genetics*; D013737:Testis / Q000187:drug effects / Q000502:physiology*
chemical_list: D015415:Biomarkers; D018832:Molecular Chaperones; D011966:Receptors, LHRH
keywords: intracellular trafficking; protein misrouting; protein trafficking