Mucosal expression of genes encoding possible upstream regulators of Na+ transport during pneumococcal otitis media.
OBJECTIVE
Recently, we reported that gene transcripts encoding 3 Na+ transport proteins (pump, channel and exchanger) in the middle ear mucosa (MEM) were simultaneously suppressed at 12 and 48 h after Streptococcus pneumoniae (SP) challenge of rat middle ears.


METHODS
From cDNA microarray screening of those specimens, several gene clusters, including Nos2 and the transcription factors Fos, Fosl1, Jun and Nfkb1, were identified as possible upstream regulators of Na+ transport protein expression. The altered expression of those genes in MEM was validated and quantified using real-time polymerase chain reaction and MEM protein expression for Atp1a1, Nos2 and Nfkb1 was studied using Western blot and/or immunohistochemistry assays.


RESULTS
At both time-points. Atp1a1 mRNA and protein were decreased and Nos2 mRNA and protein were increased in MEM. While Nfkb1 protein was decreased at those times. the corresponding mRNA was increased at 12 h but decreased at 48 h. Gene expression for Fos was suppressed at both times, while that for Fosl1 and Jun was augmented at 12 h and suppressed at 48 h. Immunohistochemical study of specimens challenged with SP showed a swollen MEM with infiltration of inflammatory cells that stained positive for Nos2.


CONCLUSIONS
Given the known activities of Nos2, these results can be interpreted as evidencing a transcriptional suppression of Na+ transport protein synthesis secondary to upregulated Nos2 expression during SP infection of the rat MEM. This proposed signaling pathway does not require the continuous upregulation of Nfkb1 or the other assayed transcription factors as early as 12 h after middle ear infection.
Li
Ha-Sheng
HS
Department of Pediatric Otolaryngology, Children's Hospital of Pittsburgh Pennsylvania 15213, USA. shengli@pitt.edu
Doyle
William J
WJ
Swarts
J Douglas
JD
Lo
Chia-Yee
CY
Hebda
Patricia A
PA
D000208:Acute Disease; D000828:Animal Population Groups; D000818:Animals; D001692:Biological Transport / Q000235:genetics; D015153:Blotting, Western; D004432:Ear, Middle / Q000378:metabolism*; D015870:Gene Expression; D020869:Gene Expression Profiling; D008297:Male; D009092:Mucous Membrane / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D010033:Otitis Media / Q000235:genetics / Q000378:metabolism*; D011008:Pneumococcal Infections / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D015222:Sodium Channels / Q000378:metabolism; D013296:Streptococcus pneumoniae / Q000302:isolation & purification; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D015222:Sodium Channels; D014157:Transcription Factors; D012964:Sodium