Gene expression differences in infected and noninfected middle ear complementary DNA libraries.
OBJECTIVE
To investigate genetic differences in middle ear mucosa (MEM) with nontypeable Haemophilus influenzae (NTHi) infection. Genetic upregulation and downregulation occurs in MEM during otitis media (OM) pathogenesis. A comprehensive assessment of these genetic differences using the techniques of complementary DNA (cDNA) library creation has not been performed.


METHODS
The cDNA libraries were constructed from NTHi-infected and noninfected chinchilla MEM. Random clones were picked, sequenced bidirectionally, and submitted to the National Center for Biotechnology Information (NCBI) Expressed Sequence Tags database, where they were assigned accession numbers. These numbers were used with the basic local alignment search tool (BLAST) to align clones against the nonredundant nucleotide database at NCBI.


RESULTS
Analysis with the Web-based statistical program FatiGO identified several biological processes with significant differences in numbers of represented genes. Processes involved in immune, stress, and wound responses were more prevalent in the NTHi-infected library. S100 calcium-binding protein A9 (S100A9); secretory leukoprotease inhibitor (SLPI); beta(2)-microglobulin (B2M); ferritin, heavy-chain polypeptide 1 (FTH1); and S100 calcium-binding protein A8 (S100A8) were expressed at significantly higher levels in the NTHi-infected library. Calcium-binding proteins S100A9 and S100A8 serve as markers for inflammation and have antibacterial effects. Secretory leukoprotease inhibitor is an antibacterial protein that inhibits stimuli-induced MUC1, MUC2, and MUC5AC production.


CONCLUSIONS
A number of genes demonstrate changes during the pathogenesis of OM, including SLPI, which has an impact on mucin gene expression; this expression is known to be an important regulator in OM. The techniques described herein provide a framework for future investigations to more thoroughly understand molecular changes in the middle ear, which will likely be important in developing new therapeutic and intervention strategies.
Kerschner
Joseph E
JE
Department of Otolaryngology and Communications Disorders, Children's Hospital of Wisconsin, 9000 W Wisconsin Ave, Milwaukee, WI 53226, USA. kersch@mcw.edu
Horsey
Edward
E
Ahmed
Azad
A
Erbe
Christy
C
Khampang
Pawjai
P
Cioffi
Joseph
J
Hu
Fen Ze
FZ
Post
James Christopher
JC
Ehrlich
Garth D
GD
D000818:Animals; D001709:Biotechnology; D040501:Calgranulin A / Q000235:genetics; D040502:Calgranulin B / Q000235:genetics; D002682:Chinchilla; D030541:Databases, Genetic; D018450:Disease Progression; D005293:Ferritins / Q000235:genetics; D015870:Gene Expression / Q000235:genetics*; D015723:Gene Library; D018396:Mucin-1 / Q000235:genetics; D009092:Mucous Membrane / Q000382:microbiology; D010033:Otitis Media / Q000235:genetics / Q000382:microbiology / Q000503:physiopathology; D053481:Secretory Leukocyte Peptidase Inhibitor / Q000235:genetics; D015854:Up-Regulation
D040501:Calgranulin A; D040502:Calgranulin B; D018396:Mucin-1; D053481:Secretory Leukocyte Peptidase Inhibitor; D005293:Ferritins