title: Intestinal Salmonella typhimurium infection leads to miR-29a induced caveolin 2 regulation.
abstract: BACKGROUND
  Salmonella are able to modulate host cell functions facilitating both uptake and resistance to cellular host defence mechanisms. While interactions between bacterial modulators and cellular proteins have been the main focus of Salmonella research, relatively little is known about mammalian gene regulation in response to Salmonella infection. A major class of mammalian gene modulators consists of microRNAs. For our study we examined interactions of microRNAs and regulated mRNAs in mammalian intestinal Salmonella infections using a piglet model.
  
  
  RESULTS
  After performing microRNA as well as mRNA specific microarray analysis of ileal samples from Salmonella infected as well as control piglets, we integrated expression analysis with target prediction identifying microRNAs that mainly regulate focal adhesion as well as actin cytoskeleton pathways. Particular attention was given to miR-29a, which was involved in most interactions including Caveolin 2. RT-qPCR experiments verified up-regulation of miR-29a after infection while its predicted target Caveolin 2 was significantly down-regulated as examined by transcript and protein detection. Reporter gene assays as well as RNAi experiments confirmed Caveolin 2 to be a miR-29a target. Knock-down of Caveolin 2 in intestinal epithelial cells resulted in retarded proliferation as well as increased bacterial uptake. In addition, our experiments showed that Caveolin 2 regulates the activation of the small Rho GTPase CDC42 but apparently not RAC1 in human intestinal cells.
  
  
  CONCLUSIONS
  Our study outlines for the first time important regulation pathways in intestinal Salmonella infection pointing out that focal adhesion and organisation of actin cytoskeleton are regulated by microRNAs. Functional relevance is shown by miR-29a mediated Caveolin 2 regulation, modulating the activation state of CDC42. Further analysis of examined interactions may support the discovery of novel strategies impairing the uptake of intracellular pathogens.
authors.affiliation: Institute of Veterinary-Biochemistry, Freie Universität Berlin, Berlin, Germany.
authors.forename: Lena
authors.initials: L
authors.lastname: Hoeke
authors.forename: Jutta
authors.initials: J
authors.lastname: Sharbati
authors.forename: Kamlesh
authors.initials: K
authors.lastname: Pawar
authors.forename: Andreas
authors.initials: A
authors.lastname: Keller
authors.forename: Ralf
authors.initials: R
authors.lastname: Einspanier
authors.forename: Soroush
authors.initials: S
authors.lastname: Sharbati
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D051243:Caveolin 2 / Q000235:genetics* / Q000378:metabolism; D049109:Cell Proliferation; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D022001:Focal Adhesions / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D053263:Gene Regulatory Networks / Q000235:genetics; D017930:Genes, Reporter; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000382:microbiology* / Q000473:pathology; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012481:Salmonella Infections, Animal / Q000235:genetics* / Q000382:microbiology* / Q000473:pathology; D012486:Salmonella typhimurium / Q000502:physiology*; D034421:Sus scrofa / Q000235:genetics / Q000382:microbiology; D015854:Up-Regulation / Q000235:genetics; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism
chemical_list: D051243:Caveolin 2; D035683:MicroRNAs; D012333:RNA, Messenger; D020764:cdc42 GTP-Binding Protein