title: Alternative splicing of SMPD1 coding for acid sphingomyelinase in major depression.
abstract: Major depressive disorder (MDD) is a psychiatric disorder characterized by key symptoms that include depressed mood and a loss of interest and pleasure. A recently developed pathogenic model of MDD involves disturbed neurogenesis in the hippocampus, where the acid sphingomyelinase (ASM)/ceramide system plays an important role and is proposed as a molecular target for antidepressant action. Because alternative splicing of SMPD1 mRNA, coding for ASM, is relevant for the regulation of ASM enzymatic activity, we investigated the frequency of alternatively spliced ASM isoforms in peripheral blood cells of MDD patients versus healthy controls.
  
  
  
  Because the full-length transcript variant 1 of SMPD1 (termed ASM-1) is the only known form within the splicing pattern that encodes an enzymatically fully active ASM, we determined a fraction of splice isoforms deviating from ASM-1 using PCR amplification and capillary electrophoresis with laser-induced fluorescence analysis.
  
  
  
  ASM alternative splicing events occurred significantly less frequently in MDD patients compared to healthy subjects. After 5 days of antidepressant treatment, the frequency of alternatively spliced ASM isoforms decreased in those patients who were treated with a functional inhibitor of ASM activity (FIASMA) but remained constant in MDD patients treated with other antidepressant drugs. This effect was more pronounced when healthy male volunteers were treated with the FIASMAs fluoxetine or paroxetine, in contrast to a placebo group.
  
  
  
  Patients were treated with different antidepressant drugs, depending on individual parameters and disease courses.
  
  
  
  This study shows that the ASM alternative splicing pattern could be a biological target with diagnostic relevance and could serve as a novel biomarker for MDD.
authors.affiliation: Department of Psychiatry and Psychotherapy, University Hospital, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Schwabachanlage 6, D-91054 Erlangen, Germany; Department of Medicine and Stony Brook Cancer Center, Stony Brook University, Stony Brook, New York, USA. Electronic address: Cosima.Rhein@uk-erlangen.de.
authors.forename: Cosima
authors.initials: C
authors.lastname: Rhein
authors.affiliation: Department of Psychiatry and Psychotherapy, University Hospital, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Schwabachanlage 6, D-91054 Erlangen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Reichel
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Jena, Germany; Genome Analysis, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany.
authors.forename: Marcel
authors.initials: M
authors.lastname: Kramer
authors.affiliation: Department of Psychiatry and Psychotherapy, University Hospital, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Schwabachanlage 6, D-91054 Erlangen, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Rotter
authors.affiliation: Department of Psychiatry and Psychotherapy, University Hospital, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Schwabachanlage 6, D-91054 Erlangen, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Lenz
authors.affiliation: Department of Psychiatry and Psychotherapy, University Hospital, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Schwabachanlage 6, D-91054 Erlangen, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Mühle
authors.affiliation: Department of Molecular Biology, University of Duisburg-Essen, Essen, Germany.
authors.forename: Erich
authors.initials: E
authors.lastname: Gulbins
authors.affiliation: Department of Psychiatry and Psychotherapy, University Hospital, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Schwabachanlage 6, D-91054 Erlangen, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Kornhuber
mesh_terms: D000328:Adult; D000368:Aged; D017398:Alternative Splicing; D000928:Antidepressive Agents / Q000009:adverse effects / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D003865:Major Depressive Disorder / Q000188:drug therapy / Q000201:enzymology* / Q000235:genetics*; D005260:Female; D005473:Fluoxetine / Q000009:adverse effects / Q000627:therapeutic use; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D017374:Paroxetine / Q000009:adverse effects / Q000627:therapeutic use; D016133:Polymerase Chain Reaction; D013108:Sphingomyelin Phosphodiesterase / Q000097:blood* / Q000235:genetics*
chemical_list: D000928:Antidepressive Agents; D015415:Biomarkers; D005473:Fluoxetine; D017374:Paroxetine; C543066:SMPD1 protein, human; D013108:Sphingomyelin Phosphodiesterase
keywords: Acid sphingomyelinase; Alternative splicing; Antidepressant drugs; Fluoxetine; Functional inhibitors of ASM activity (FIASMAs); Major depression; Paroxetine