Dataset Information


Transcript analysis in response to ozone in mice deficient in TLR4

ABSTRACT: We previously identified toll-like receptor 4 (Tlr4) as a candidate gene responsible for ozone (O3)-induced pulmonary hyperpermeability and inflammation. The objective of this study was to determine the mechanism through which TLR4 modulates O3-induced pulmonary responses and to utilize transcriptomics to determine TLR4 effector molecules. C3H/HeJ (HeJ; Tlr4 mutant) and C3H/HeOuJ (OuJ; Tlr4 normal), mice were exposed continuously to 0.3 ppm O3 or filtered air for 6, 24, 48 or 72 hr. Affymetrix Mouse430A_MOE gene arrays were used to analyze lung homogenates from HeJ and OuJ mice followed using a bioinformatic analysis. Inflammation was assessed by bronchoalveolar lavage and molecular analysis by ELISA, immunoblotting, and transcription factor activity. TLR4 signals through both the MYD88-dependent and independent pathways in OuJ mice, which involves MAP kinase activation, NF-kappaB, AP-1, and KC. Microarray analyses identifiedTLR4 responsive genes for strain and time in OuJ versus HeJ mice (p<0.05). One significantly upregulated cluster of genes in OuJ were the heat shock proteins (Hspa1b; Hsp70), Hsp90ab1). Furthermore, O3-induced expression of HSP70 protein was increased in OuJ compared to HeJ mice following 24-48 h O3. Moreover, BAL polymorphonuclear leukocytes (PMN) and total protein were significantly reduced in response to O3 in Hspa1a/Hspa1btm1Dix (Hsp70-/-) compared to Hsp70+/+ mice (p<0.05). TLR4 signaling (MYD88-dependent), ERK1/2, AP-1 activity, and KC protein content were also significantly reduced after O3 exposure in Hsp70-/- compared to Hsp70+/+ mice (p<0.05). These studies suggest that HSP70 is involved in the regulation of O3-induced lung inflammation through the TLR4 pathway and provide evidence that HSP70 is an endogenous in vivo TLR4 ligand. Overall design: Two strains of mice were used for these studies. The C3H/HeJ with a dominant negative Tlr4 and the C3H/HeOuJ mice with a sufficient Tlr4. Total RNA was extracted from left lung lobes (air, 6, 24, 48 hr of O3 exposure for OuJ and HeJ mice; n = 3 per treatment group). Therefore a total of 24 arrays with 3 different ozone exposure times and 1 air exposure.

INSTRUMENT(S): [MOE430A] Affymetrix Mouse Expression 430A Array

SUBMITTER: Alison Kendall Bauer  

PROVIDER: GSE20715 | GEO | 2012-02-29



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Identification of candidate genes downstream of TLR4 signaling after ozone exposure in mice: a role for heat-shock protein 70.

Bauer Alison K AK   Rondini Elizabeth A EA   Hummel Kristin A KA   Degraff Laura M LM   Walker Christopher C   Jedlicka Anne E AE   Kleeberger Steven R SR  

Environmental health perspectives 20110504 8

Toll-like receptor 4 (TLR4) is involved in ozone (O3)-induced pulmonary hyperpermeability and inflammation, although the downstream signaling events are unknown.The aims of our study were to determine the mechanism through which TLR4 modulates O3-induced pulmonary responses and to use transcriptomics to determine potential TLR4 effector molecules.C3H/HeJ (HeJ; Tlr4 mutant) and C3H/HeOuJ (OuJ; Tlr4 normal) mice were exposed continuously to 0.3 ppm O3 or filtered air for 6, 24, 48, or 72 hr. We as  ...[more]

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