title: Rescue of Isolated GH Deficiency Type II (IGHD II) via Pharmacologic Modulation of GH-1 Splicing.
abstract: Isolated GH deficiency (IGHD) type II, the autosomal dominant form of GHD, is mainly caused by mutations that affect splicing of GH-1. When misspliced RNA is translated, it produces a toxic 17.5-kDa GH isoform that reduces the accumulation and secretion of wild-type-human GH (wt-hGH). Usually, isolated GHD type II patients are treated with daily injections of recombinant human GH in order to maintain normal growth. However, this type of replacement therapy does not prevent toxic effects of the 17.5-kDa GH isoform on the pituitary gland, which can eventually lead to other hormonal deficiencies. Here, we tested the possibility to restore the constitutive splicing pattern of GH-1 by using butyrate, a drug that mainly acts as histone deacetylase inhibitor. To this aim, wt-hGH and/or different hGH-splice site mutants (GH-IVS3+2, GH-IVS3+6, and GH-ISE+28) were transfected in rat pituitary cells expressing human GHRH receptor (GHRHR) (GC-GHRHR). Upon butyrate treatment, GC-GHRHR cells coexpressing wt-hGH and each of the mutants displayed increased GH transcript level, intracellular GH content, and GH secretion when compared with the corresponding untreated condition. The effect of butyrate was most likely mediated by the alternative splicing factor/splicing factor 2. Overexpression of alternative ASF/SF2 in the same experimental setting, indeed, promoted the amount of full-length transcripts thus increasing synthesis and secretion of the 22-kDa GH isoform. In conclusion, our results support the hypothesis that modulation of GH-1 splicing pattern to increase the 22-kDa GH isoform levels can be clinically beneficial and hence a crucial challenge in GHD research.
authors.affiliation: Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics and Department of Clinical Research, Inselspital, Bern University Hospital, University of Bern, Bern, CH-3010 Switzerland.
authors.forename: Maria Consolata
authors.initials: MC
authors.lastname: Miletta
authors.affiliation: Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics and Department of Clinical Research, Inselspital, Bern University Hospital, University of Bern, Bern, CH-3010 Switzerland.
authors.forename: Vibor
authors.initials: V
authors.lastname: Petkovic
authors.affiliation: Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics and Department of Clinical Research, Inselspital, Bern University Hospital, University of Bern, Bern, CH-3010 Switzerland.
authors.forename: Andrée
authors.initials: A
authors.lastname: Eblé
authors.affiliation: Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics and Department of Clinical Research, Inselspital, Bern University Hospital, University of Bern, Bern, CH-3010 Switzerland.
authors.forename: Christa E
authors.initials: CE
authors.lastname: Flück
authors.affiliation: Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics and Department of Clinical Research, Inselspital, Bern University Hospital, University of Bern, Bern, CH-3010 Switzerland.
authors.forename: Primus-E
authors.initials: PE
authors.lastname: Mullis
mesh_terms: D000818:Animals; D002087:Butyrates / Q000494:pharmacology / Q000627:therapeutic use*; D002460:Cell Line; D004353:Drug Evaluation, Preclinical; D004393:Dwarfism, Pituitary / Q000188:drug therapy*; D018014:Gene Transfer Techniques; D013006:Growth Hormone / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D012326:RNA Splicing / Q000187:drug effects*; D051381:Rats; D018013:Receptors, Neuropeptide / Q000235:genetics / Q000378:metabolism; D018017:Receptors, Pituitary Hormone-Regulating Hormone / Q000235:genetics / Q000378:metabolism
chemical_list: D002087:Butyrates; D018013:Receptors, Neuropeptide; D018017:Receptors, Pituitary Hormone-Regulating Hormone; D013006:Growth Hormone; C048250:somatotropin releasing hormone receptor