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Intermittent Leucine Pulses during Continuous Feeding Alters Novel Components Involved in Skeletal Muscle Growth of Neonatal Pigs
Author(s) -
Suryawan Agus,
Boutry Claire,
Manjarín Rodrigo,
Cánovas Angela,
IslasTrejo Alma,
Medrano Juan F,
Nguyen Hanh,
Fiorotto Marta L.,
Davis Teresa A.
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.430.2
Subject(s) - biology , skeletal muscle , anabolism , gene , leucine , medicine , biochemistry , endocrinology , amino acid
Extra‐uterine growth restriction in low‐birth‐weight (LBW) infants is associated with the development of chronic metabolic derangements, and emphasizes the need for improved nutritional protocols to optimize growth. Supplementation with intermittent pulses of leucine in continuously fed neonatal pigs enhanced skeletal muscle protein synthesis through the upregulation of mammalian target of rapamycin signaling. Piglets (n = 23, 7‐d‐old) were continuously fed a milk formula via orogastric tube for 21 d, with an additional parenteral infusion of either leucine (800 μmol·kg −1 ·h −1 , LEU) or alanine (CON) for 1 h every 4 h. To identify novel genes by which LEU may promote neonatal muscle growth, we performed RNA‐Seq analysis of longissimus dorsi muscle from 4 pigs per group, followed by gene ontology (GO) analysis of differentially expressed genes (DEG). In addition, protein abundance/activation of DEG products involved in both muscle protein anabolic or catabolic pathways was assessed by immunoblots. RNA‐Seq was performed on a HiSeq2000 sequencer analyzer. Reads were analyzed using CLCBio Genomics workbench software, assembled against the porcine reference genome, and normalized by a threshold of ‘reads per kilo base per million mapped reads’ (RPKM) ≥ 0.2. A total of 465 genes were differentially expressed between LEU and CON groups (RPKM P < 0.05). GO analyses showed developmental processes, cell junction assembly, regulation of cellular process and organ development as the terms most significantly enriched among the 465 genes. Applying more stringent parameters (RPKM P < 0.01 + >2 fold change), 18 differential expressed genes were identified between CON and LEU pigs, of which tumor necrosis factor receptor‐associated factor 6 (TRAF6) and mammalian Ste20‐like kinase 1 (MST1), both negative regulators of muscle growth, were decreased by > 2‐fold ( P < 0.01) in LEU compared to CON. Western blot analysis also showed a downregulation of MST1 and TRAF6 abundance in LEU animals ( P < 0.01) compared to CON. Together, these findings suggest that intermittent leucine pulses in continuously fed neonate pigs lead to downregulation in the gene and protein expression of signaling components that limit muscle growth. Support or Funding Information NIH AR444474, NIHHD072891, USDA NIFA 2013‐67015‐20438, and USDA/ARS 6250‐51000‐055