Project description:Acute kidney injury (AKI) is associated with an abrupt loss of kidney function that results in significant morbidity and mortality. Considerable effort has focused around the identification of diagnostic biomarkers and the analysis of molecular events. Most studies have adopted organ-wide approaches that do not fully capture the interplay among different cell types in the pathophysiology of AKI. To extend our understanding of molecular and cellular events in AKI, we developed a mouse line that enables the identification of translational profiles in specific cell types by CRE recombinase-dependent activation of an eGFP-tagged L10a ribosomal protein subunit, and consequently, translating ribosome affinity purification (TRAP) of mRNA populations. By utilizing cell-type specific CRE-driver lines, in this study we identify distinct cellular responses in an ischemia reperfusion injury (IRI) model of AKI. Cell-specific translational expression profiles were uncovered 24 hours after IRI from four populations enriched for distinct anatomical and cellular subgroups: nephron, interstitial cell populations, vascular endothelium, and macrophages/monocytes by Affymetrix microarray. A construct containing the CAGGS promoter driving eGFP-L10a, with a loxP-site flanked triple SV40 polyA cassette between promoter and eGFP-L10a cassette was targeted into the ubiquitously active Rosa26 locus. The upstream polyA cassette is designed to block activity of the downstream eGFP-L10a cassette. CRE-dependent removal of this transcriptional block activates eGFP::L10a production within the CRE-producing cell, and all of its descendants. Mice carrying the conditional eGFP-L10a allele, referred to as L10a, were maintained in a homozygous state. L10a mice were crossed to four CRE strains to activate eGFP::L10a expression in four predominantly non-overlapping cellular compartments in the kidney. A Six2-Tet-GFP::CRE allele is active exclusively within nephron progenitors; consequently, historical labeling results in eGFP::L10a expression throughout the main body of the nephron. A Foxd1-GFP::CRE allele is active in the progenitors of many of the interstitial cell lineages including those generating mesangial and non-glomerular pericytes. In addition, Foxd1 is normally expressed in podocytes. Cdh5-CRE is reported to be active throughout the vascular endothelium, and finally, Lyz2-CRE specifically labels cells of the myeloid lineage, notably macrophages, monocytes and dendritic cells. Mice carrying any CRE allele and the L10a allele are designated generically CRE-L10a. six2-L10a, foxd1-L10a, cdh5-L10a and lyz2-L10a denote specifically mice that are compound heterozygotes for the indicated CRE driver and L10a. CRE-L10a, L10a heterozygous littermates without CRE allele, C57BL/6 wild type mice were subjected to renal bilateral warm ischemia 28 minutes followed by 24-hour reperfusion when the kidney TRAP RNA and total RNA were isolated and subjected to Affymetrix microarray. Biological triplicates for each CRE-L10a line underwent no Surgery; sham Surgery and IRI treatment.
Project description:Selenium (Se) is an essential nutrient for beef cattle health and commercial production. The molecular mechanisms responsible for the physiological responses of the animal to dietary Se supplementation, however, have not been evaluated. Furthermore, the potential effect of two chemical forms (organic vs. inorganic) of Se on gene expression by Se-sufficient cattle has not been evaluated. Microarray analysis using the GeneChip Bovine Genome Array (Affymetrix, Inc., Santa Clara, CA) was conducted to determine if dietary Se supplementation in organic vs. inorganic form (OSe vs. ISe) differentially affects the liver gene expression profile in growing beef heifers.
Project description:Selenium (Se) is an essential nutrient for beef cattle health and commercial production. The molecular mechanisms responsible for physiological responses of the animal to dietary Se supplementation, however, have not been evaluated. Furthermore, the potential effect of two chemical forms (organic vs. inorganic) of Se on gene expression by Se-sufficient cattle has not been evaluated. Microarray analysis using the GeneChip Bovine Genome Array (Affymetrix, Inc., Santa Clara, CA) was conducted to determine if dietary Se supplementation in organic vs. inorganic form (OSe vs. ISe) differentially affects the liver gene expression profile in growing beef heifers. Sodium selenite (Prince Se Concentrate; Prince Agri Products, Inc., Quincy, IL) was used as the source of ISe form. Se-enriched yeast (Sel-Plex; Alltech, Inc., Nicholasville, KY) was used as the source of OSe form. Thirty Angus heifers (BW 393 ± 9 kg) were randomly assigned to 3 dietary treatments (n = 10): Control (Ctrl) group received no dietary Se supplementation; ISe treatment group daily received dietary supplementation of Se at 3 mg/animal from ISe source; OSe treatment group daily received dietary supplementation of Se at 3 mg/animal from OSe source. Six animals were randomly selected from each of 3 treatment groups for RNA extraction and microarray analysis.