Identification of candidate rhinovirus C (RV-C) receptors by gene expression analysis

Members of rhinovirus C (RV-C) species are more likely to cause wheezing illnesses and asthma exacerbations compared to other rhinoviruses. The cellular receptor for these viruses was heretofore unknown. We measured gene expression (Human Gene 1.0 ST Array, Affymetrix) in two series of experiments involving cells that were either susceptible or not susceptible to RV-C infection. In one experimental series, susceptible cells included whole sinus mucosal tissue specimens (n = 5), epithelial cell suspension from sinus tissue, and nasal epithelium obtained via brushing, while non-susceptible cells included monolayers of primary undifferentiated epithelial cells and transformed cell lines (n = 5). In a second experimental series, we compared three pairs of undifferentiated and fully differentiated (ALI) sinus epithelial cell cultures. We identified a total of 12 genes upregulated in RV-C susceptible cells (represented by 14 probe sets) encoding proteins localized to plasma membrane, and/or with predicted or functionally demonstrated receptor activity, including members of the Human MHC class II, stomatin, guanine nucleotide-binding, type I cytokine and atypical chemokine receptor and cadherin protein families. Sinus and bronchial epithelial tissue samples were obtained from residual surgical specimens. Primary airway epithelial cells were cultured submerged (undifferentiated monolayers) or at air-liquid interface (fully-differentiated). Established cell lines (HeLa, NCI-H358 and WisL) were cultured submerged. Epithelial tissue samples were placed in RNAlater solution (Life Technologies) to stabilize and protect cellular RNA; cultured cells were lysed directly and total RNAs were isolated using TRIzol reagent (Life Technologies). Gene expression was analyzed using the Human Genome 1.0 ST GeneChip arrays (Affymetrix, Santa Clara, CA).