Project description:A summary of the work associated to these microarrays is the following: Diet plays a role in the development of the immune system, and polyunsaturated fatty acids can modulate the expression of a variety of genes. Human milk contains conjugated linoleic acid (CLA), a fatty acid that seems to contribute to immune development. Indeed, recent studies carried out in our group in suckling animals have shown that the immune function is enhanced after feeding 80:20 isomer mix of c9,t11 and t10,c12 CLA, respectively. However, little work has been done on the effects of CLA on gene expression, and even less regarding immune system development in early life. With all these concepts in mind, we determined the expression profile of Mesentheric Lymph Nodes (MLN) from animals supplemented with CLA during gestation and suckling through dam’s milk (Group A) or by oral gavage (Group B), supplemented just during suckling (Group C) and control animals (Group D) with the aid of the specific GeneChip ® Rat Genome 230 2.0 (Affymettrix). Bioinformatic analyses were performed using the GeneSpring GX software package v10.0.2 and lead to the identification of 123 genes differentially expressed in all three dietary approaches. Generation of a Biological Association Network (BAN) evidenced several genes, such as connective tissue growth factor (Ctgf), tissue inhibitor of metalloproteinase 1 (Timp1), galanin (Gal), synaptotagmin 1 (Syt1), growth factor receptor bound protein 2 (Grb2) actin gamma 2 (Actg2) and smooth muscle alpha actin (Acta2), as highly interconnected nodes of the resulting network. Gene underexpression was confirmed by Real-Time RT-PCR. We conclude that Ctgf, Timp1, Gal and Syt1, among others, are genes modulated by CLA supplementation that may have a role on lymphoproliferation and mucosal immune responses in early life. The aim of our study was to evaluate, by using whole genome microarrays, the effects of dietary supplementation with an 80:20 isomer mix of c9,t11 and t10,c12 CLA, respectively, on Mesentheric Lymph Nodes gene expression, during gestation and/or suckling. Three experimental approaches were conducted to assess the effects of CLA supplementation on I) pups from dams fed with 1% CLA diet during the two weeks of gestation and throughout the suckling period (Group A). These pups received CLA through the dam’s milk during suckling (Total Period of CLA Supplementation (TPS) 5 wk); II) pups from dams fed with 1% CLA diet during gestation and standard diet during suckling. These pups were CLA-supplemented daily during suckling by oral gavage (TPS 5 wk) (Group B); III) pups from dams fed standard diet during gestation and suckling and receiving CLA by daily oral gavage throughout the suckling period (TPS 3 wk) (Group C). Group D, pups from dams fed standard diet throughout the study, constituted the reference diet group (TPS 0 wk). Triplicate samples were hybridized for each experimental condition (12 samples in total). The samples provided were analyzed using the specific software GeneSpring GX.

Project description:In Dendritic cells (DC), the MHC II eluted immunopeptidome reflects the antigenic composition of the microenvironment. Proteins are transported and processed into peptides in endosomal MHC II compartments through autophagy or phagocytosis; extracellular peptides can also directly bind MHC II proteins at the cell surface. Altogether, these mechanisms allow DC to sample both the intra and extracellular environment. To understand the contribution of the lymph proteome to the MHC-II immunopeptidome we eluted I-Ab complexes from DCs harvested from the deep cervical or mesenteric nodes and investigated whether the I-Ab presented peptidome reflects the anatomical distribution of the proteomes carried by the lymph collected from the same anatomical districts. Heatmap representation and cluster analysis indicated differences among the two immunopeptidome. Similarly, regression analysis showed a much higher regression coefficient among MHC II immunopeptidomes eluted from the same anatomical district (r=0.699) as compared to the one eluted from the two different anatomical districts (deep cervical, average r = 0.877 and mesenteric, average r = 0.937). Overall, all analyzed peptides displayed the expected I-Ab binding motives, binding affinity and expected range of peptide length. A combination of data dependent (DDA) and data independent (DIA) analysis indicated that around 36% of the eluted peptides were shared by both the cervical and mesenteric lymph nodes. The rest of the eluted peptides were distinct to each lymph node reflecting the qualitatively different proteome associated with each of the two anatomical districts: peptides unique to the cervical lymph nodes displayed many proteins known to be enriched in brain tissue, whereas those unique to mesenteric lymph nodes were enriched in mesenteric organ proteins. As such, the quantitative analysis of the I-Ab-eluted immunopeptidomes pinpoint important differences in peptide presentation and epitope selection in distinct anatomical districts.

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Rattus norvegicus

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