Gene Expression during the Generation and Activation of Mouse Neutrophils: Implication of Novel Functional and Regulatory Pathways

As part of the Immunological Genome Project (ImmGen), gene expression was determined in unstimulated (circulating) mouse neutrophils and three populations of neutrophils activated in vivo, with comparison among these populations and to other leukocytes. Activation conditions included serum-transfer arthritis (mediated by immune complexes), thioglycollate-induced peritonitis, and uric acid-induced peritonitis. Neutrophils expressed fewer genes than any other leukocyte population studied in ImmGen, and down-regulation of genes related to translation was particularly striking. However, genes with expression relatively specific to neutrophils were also identified, particularly three genes of unknown function: Stfa2l1, Mrgpr2a and Mrgpr2b. Comparison of genes up-regulated in activated neutrophils led to several novel findings: increased expression of genes related to synthesis and use of glutathione and of genes related to uptake and metabolism of modified lipoproteins, particularly in neutrophils elicited by thioglycollate; increased expression of genes for transcription factors in the Nr4a family, only in neutrophils elicited by serum-transfer arthritis; and increased expression of genes important in synthesis of prostaglandins and response to leukotrienes, particularly in neutrophils elicited by uric acid. Up-regulation of genes related to apoptosis, response to microbial products, NFkB family members and their regulators, and MHC class II expression was also seen, in agreement with previous studies. A regulatory model developed from the ImmGen data was used to infer regulatory genes involved in the changes in gene expression during neutrophil activation. Among 64, mostly novel, regulatory genes predicted to influence these changes in gene expression, Irf5 was shown to be important for optimal secretion of IL-10, IP-10, MIP-1α, MIP-1β, and TNF-α by mouse neutrophils in vitro after stimulation through TLR9. This data-set and its analysis using the ImmGen regulatory model provide a basis for additional hypothesis-based research on the importance of changes in gene expression in neutrophils in different conditions

Fat in the skin: Triacylglycerol metabolism in keratinocytes and its role in the development of neutral lipid storage disease

Keratinocyte differentiation is essential for skin development and the formation of the skin permeability barrier. This process involves an orchestrated remodeling of lipids. The cleavage of precursor lipids from lamellar bodies by β-glucocerebrosidase, sphingomyelinase, phospholipases and sterol sulfatase generates ceramides, non-esterified fatty acids and cholesterol for the lipid-containing extracellular matrix, the lamellar membranes in the stratum corneum. The importance of triacylglycerol (TAG) hydrolysis for the formation of a functional permeability barrier was only recently appreciated. Mice with defects in TAG synthesis (acyl-CoA:diacylglycerol acyltransferase-2-knock-out) or TAG catabolism (comparative gene identification-58, -CGI-58-knock-out) develop severe permeability barrier defects and die soon after birth because of desiccation. In humans, mutations in the CGI-58 gene also cause (non-lethal) neutral lipid storage disease with ichthyosis. As a result of defective TAG synthesis or catabolism, humans and mice lack ω-(O)-acylceramides, which are essential lipid precursors for the formation of the corneocyte lipid envelope. This structure plays an important role in linking the lipid-enriched lamellar membranes to highly cross-linked corneocyte proteins. This review focuses on the current knowledge of biochemical mechanisms that are essential for epidermal neutral lipid metabolism and the formation of a functional skin permeability barrier

Impact of protein supplementation during endurance training on changes in skeletal muscle transcriptome

Background: Protein supplementation improves physiological adaptations to endurance training, but the impact on adaptive changes in the skeletal muscle transcriptome remains elusive. The present analysis was executed to determine the impact of protein supplementation on changes in the skeletal muscle transcriptome following 5- weeks of endurance training. Results: Skeletal muscle tissue samples from the vastus lateralis were taken before and after 5-weeks of endurance training to assess changes in the skeletal muscle transcriptome. One hundred and 63 genes were differentially expressed after 5-weeks of endurance training in both groups (q-value 0.05). Endurance training primarily affected expression levels of genes related to extracellular matrix and these changes tended to be greater in PRO than in CON. Conclusions: Protein supplementation subtly impacts endurance training-induced changes in the skeletal muscle transcriptome. In addition, our transcriptomic analysis revealed that the extracellular matrix may be an important factor for skeletal muscle adaptation in response to endurance training. This trial was registered at clinicaltrials.gov as NCT03462381, March 12, 201

Benchmark thermochemistry of the C_nH_{2n+2} alkane isomers (n=2--8) and performance of DFT and composite ab initio methods for dispersion-driven isomeric equilibria

The thermochemistry of linear and branched alkanes with up to eight carbons has been reexamined by means of W4, W3.2lite and W1h theories. `Quasi-W4' atomization energies have been obtained via isodesmic and hypohomodesmotic reactions. Our best atomization energies at 0 K (in kcal/mol) are: 1220.04 n-butane, 1497.01 n-pentane, 1774.15 n-hexane, 2051.17 n-heptane, 2328.30 n-octane, 1221.73 isobutane, 1498.27 isopentane, 1501.01 neopentane, 1775.22 isohexane, 1774.61 3-methylpentane, 1775.67 diisopropyl, 1777.27 neohexane, 2052.43 isoheptane, 2054.41 neoheptane, 2330.67 isooctane, and 2330.81 hexamethylethane. Our best estimates for $\Delta H^\circ_{f,298K}$ are: -30.00 n-butane, -34.84 n-pentane, -39.84 n-hexane, -44.74 n-heptane, -49.71 n-octane, -32.01 isobutane, -36.49 isopentane, -39.69 neopentane, -41.42 isohexane, -40.72 3-methylpentane, -42.08 diisopropyl, -43.77 neohexane, -46.43 isoheptane, -48.84 neoheptane, -53.29 isooctane, and -53.68 hexamethylethane. These are in excellent agreement (typically better than 1 kJ/mol) with the experimental heats of formation at 298 K obtained from the CCCBDB and/or NIST Chemistry WebBook databases. However, at 0 K a large discrepancy between theory and experiment (1.1 kcal/mol) is observed for only neopentane. This deviation is mainly due to the erroneous heat content function for neopentane used in calculating the 0 K CCCBDB value. The thermochemistry of these systems, especially of the larger alkanes, is an extremely difficult test for density functional methods. A posteriori corrections for dispersion are essential. Particularly for the atomization energies, the B2GP-PLYP and B2K-PLYP double-hybrids, and the PW6B95 hybrid-meta GGA clearly outperform other DFT functionals.Comment: (J. Phys. Chem. A, in press