TY - JOUR
T1 - Global transcriptional responses of wild-type Aeromonas hydrophila and its virulence-deficient mutant in a murine model of infection
AU - Fadl, Amin A.
AU - Galindo, Cristi L.
AU - Sha, Jian
AU - Zhang, Fan
AU - Garner, Harold R.
AU - Wang, Hui Qun
AU - Chopra, Ashok K.
N1 - Funding Information:
This work was supported by a grant from the NIH/NIAID (AI41611), the Gastrointestinal Research Interdisciplinary Program (GRIP), University of Texas Medical Branch (UTMB), Galveston, TX, and the Regional Centers of Excellence in Biodefense (5 U54 A105158-02). Funds provided by the American Water Works Association Research Foundation and the Environmental Protection Agency were also crucial for the completion of these studies. A.A. Fadl was supported by the McLaughlin Postdoctoral Fellowship, and C.L. Galindo received support from an NIH cardiology fellowship, Cardiology Department, University of Texas Southwestern Medical Center. Dr. T. Wood from the department of Biochemistry and Molecular Biology at UTMB provided facility of his core laboratory for microarray studies. Excellent help of Shao F. Wang with graphics is also acknowledged.
PY - 2007/5
Y1 - 2007/5
N2 - We previously generated a double knockout mutant (act/aopB) of a diarrheal isolate SSU of A. hydrophila, in which the genes encoding Aeromonas outer membrane protein B (AopB), a structural component of the type III secretion system (T3SS), and a type II (T2)-secreted cytotoxic enterotoxin gene (act) were deleted. This mutant exhibited minimal virulence in mice, compared to animals infected with wild-type (WT) A. hydrophila. Based on microarray analyses, WT A. hydrophila altered the expression of 434 and 80 genes in murine macrophages (RAW 264.7) and human colonic epithelial cells (HT-29), respectively. Approximately half of these gene expression alterations were abrogated when host cells were infected instead with the act/aopB mutant. In this study, we used microarrays to examine early host transcriptional responses in spleens of mice infected for 3 h with WT A. hydrophila or its act/aopB mutant. Our data indicated that expression of 221 genes was altered (158 up-regulated and 63 down-regulated) in spleens of WT bacteria-infected animals. There were 21 genes that were consistently more highly expressed in WT A. hydrophila-infected mice, compared to mice infected with its act/aopB mutant. Ten of these genes were either induced to a lesser extent (e.g., interleukin-6, macrophage inflammatory protein-2, and cyclooxygenase-2), not altered at all (e.g., killer cell lectin-like receptor subfamily B member A), or down-regulated (e.g., cytochrome P450) in animals infected with A. hydrophila, compared to phosphate-buffered saline-infected control animals, when the mutant was used instead of the WT. We verified the microarray results at the transcript level by performing real-time reverse transcriptase-polymerase chain reaction on selected genes and at the protein level by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. This is the first study demonstrating in vivo gene regulation in mice infected with A. hydrophila and the contribution of virulence factors and host responses to the disease process.
AB - We previously generated a double knockout mutant (act/aopB) of a diarrheal isolate SSU of A. hydrophila, in which the genes encoding Aeromonas outer membrane protein B (AopB), a structural component of the type III secretion system (T3SS), and a type II (T2)-secreted cytotoxic enterotoxin gene (act) were deleted. This mutant exhibited minimal virulence in mice, compared to animals infected with wild-type (WT) A. hydrophila. Based on microarray analyses, WT A. hydrophila altered the expression of 434 and 80 genes in murine macrophages (RAW 264.7) and human colonic epithelial cells (HT-29), respectively. Approximately half of these gene expression alterations were abrogated when host cells were infected instead with the act/aopB mutant. In this study, we used microarrays to examine early host transcriptional responses in spleens of mice infected for 3 h with WT A. hydrophila or its act/aopB mutant. Our data indicated that expression of 221 genes was altered (158 up-regulated and 63 down-regulated) in spleens of WT bacteria-infected animals. There were 21 genes that were consistently more highly expressed in WT A. hydrophila-infected mice, compared to mice infected with its act/aopB mutant. Ten of these genes were either induced to a lesser extent (e.g., interleukin-6, macrophage inflammatory protein-2, and cyclooxygenase-2), not altered at all (e.g., killer cell lectin-like receptor subfamily B member A), or down-regulated (e.g., cytochrome P450) in animals infected with A. hydrophila, compared to phosphate-buffered saline-infected control animals, when the mutant was used instead of the WT. We verified the microarray results at the transcript level by performing real-time reverse transcriptase-polymerase chain reaction on selected genes and at the protein level by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. This is the first study demonstrating in vivo gene regulation in mice infected with A. hydrophila and the contribution of virulence factors and host responses to the disease process.
KW - Aeromonas hydrophila
KW - Affymetrix microarrays
KW - Cytokine and prostaglandin production
KW - Immunohistochemistry
KW - Isogenic mutants
KW - Mouse model of infection
KW - Type 2 and type 3-associated bacterial virulence
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U2 - 10.1016/j.micpath.2007.02.002
DO - 10.1016/j.micpath.2007.02.002
M3 - Article
C2 - 17368824
AN - SCOPUS:34247546647
SN - 0882-4010
VL - 42
SP - 193
EP - 203
JO - Microbial Pathogenesis
JF - Microbial Pathogenesis
IS - 5-6
ER -