title: Brainstem deficiency of the 14-3-3 regulator of serotonin synthesis: a proteomics analysis in the sudden infant death syndrome.
abstract: Impaired brainstem responses to homeostatic challenges during sleep may result in the sudden infant death syndrome (SIDS). Previously we reported a deficiency of serotonin (5-HT) and its key biosynthetic enzyme, tryptophan hydroxylase (TPH2), in SIDS infants in the medullary 5-HT system that modulates homeostatic responses during sleep. Yet, the underlying basis of the TPH2 and 5-HT deficiency is unknown. In this study, we tested the hypothesis that proteomics would uncover previously unrecognized abnormal levels of proteins related to TPH2 and 5-HT regulation in SIDS cases compared with controls, which could provide novel insight into the basis of their deficiency. We first performed a discovery proteomic analysis of the gigantocellularis of the medullary 5-HT system in the same data set with deficiencies of TPH2 and 5-HT levels. Analysis in 6 SIDS cases and 4 controls revealed a 42-75% reduction in abundance in 5 of the 6 isoforms identified of the 14-3-3 signal transduction family, which is known to influence TPH2 activity (p < 0.07). These findings were corroborated in an additional SIDS and control sample using an orthogonal MS(E)-based quantitative proteomic strategy. To confirm these proteomics results in a larger data set (38 SIDS, 11 controls), we applied Western blot analysis in the gigantocellularis and found that 4/7 14-3-3 isoforms identified were significantly reduced in SIDS cases (p ≤ 0.02), with a 43% reduction in all 14-3-3 isoforms combined (p < 0.001). Abnormalities in 5-HT and TPH2 levels and 5-HT(1A) receptor binding were associated with the 14-3-3 deficits in the same SIDS cases. These data suggest a potential molecular defect in SIDS related to TPH2 regulation, as 14-3-3 is critical in this process.
authors: Department of Pathology, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts; Proteomics Center, Children's Hospital Boston, Boston, Massachusetts. Electronic address: kevin.broadbelt@childrens.harvard.edu.
authors: Kevin G
authors: KG
authors: Broadbelt
authors: Department of Pathology, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts.
authors: Keith D
authors: KD
authors: Rivera
authors: Department of Pathology, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts.
authors: David S
authors: DS
authors: Paterson
authors: Department of Pathology, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts.
authors: Jhodie R
authors: JR
authors: Duncan
authors: New England Research Institutes, Watertown, Massachusetts.
authors: Felicia L
authors: FL
authors: Trachtenberg
authors: Department of Pathology, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts; Proteomics Center, Children's Hospital Boston, Boston, Massachusetts.
authors: Joao A
authors: JA
authors: Paulo
authors: Waters Corporation, Milford, Massachusetts.
authors: Martha D
authors: MD
authors: Stapels
authors: Department of Pathology, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts.
authors: Natalia S
authors: NS
authors: Borenstein
authors: Department of Pathology, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts.
authors: Richard A
authors: RA
authors: Belliveau
authors: Rady Children's Hospital San Diego and University of California, San Diego School of Medicine, La Jolla, California.
authors: Elisabeth A
authors: EA
authors: Haas
authors: San Diego County Medical Examiner's Office, San Diego, California.
authors: Christina
authors: C
authors: Stanley
authors: Rady Children's Hospital San Diego and University of California, San Diego School of Medicine, La Jolla, California.
authors: Henry F
authors: HF
authors: Krous
authors: Department of Pathology, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts; Proteomics Center, Children's Hospital Boston, Boston, Massachusetts.
authors: Hanno
authors: H
authors: Steen
authors: Department of Pathology, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts.
authors: Hannah C
authors: HC
authors: Kinney
mesh_terms: D048948:14-3-3 Proteins / Q000172:deficiency*; D001933:Brain Stem / Q000378:metabolism*; D002853:Chromatography, Liquid; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D013058:Mass Spectrometry; D040901:Proteomics; D012701:Serotonin / Q000172:deficiency*; D013398:Sudden Infant Death; D014365:Tryptophan Hydroxylase / Q000172:deficiency*
chemical_list: D048948:14-3-3 Proteins; D012701:Serotonin; D014365:Tryptophan Hydroxylase