Transcriptional Changes Induced by Bovine Papillomavirus Type 1 in Equine Fibroblasts

Abstract

Bovine papillomavirus type 1 (BPV-1) and, less commonly, BPV-2 are associated with the pathogenesis of common equine skin tumors termed sarcoids. In an attempt to understand the mechanisms by which BPV-1 induces sarcoids, we used gene expression profiling as a screening tool to identify candidate genes implicated in disease pathogenesis. Gene expression profiles of equine fibroblasts transformed by BPV-1 experimentally or from explanted tumors were compared with those of control equine fibroblasts to identify genes associated with expression of BPV-1. Analysis of the microarray data identified 81 probe sets that were significantly (P < 0.01) differentially expressed between the BPV-1-transformed and control cell lines. Expression of several deregulated genes, including MMP-1, CXCL5, FRA-1, NKG7, TLR4, and the gene encoding the major histocompatibility complex class I (MHC-I) protein, was confirmed using other BPV-1-transformed cell lines. Furthermore, expression of these genes was examined using a panel of 10 sarcoids. Increased expression of MMP-1, CXCL5, FRA-1, and NKG7 was detected in a subset of tumors, and TLR4 and MHC I showed robust down-regulation in all tumors. Deregulated expression was confirmed at the protein level for MMP-1 and MHC-I. The present report identifies genes modulated by BPV-1 transformation and will help identify the molecular mechanisms involved in disease pathogenesis.

Effects of human papillomavirus type 16 E5 deletion mutants on epithelial morphology: functional characterization of each transmembrane domain

“…The gene for MMP1 is overexpressed in HPV-associated cervical cancer and in BPV-1-associated equine sarcoids (Narayan et al, 2007;Yuan et al, 2008), but the papillomavirus proteins involved in the transcriptional activation of the MMP1 gene in these tumours have not yet been identified. MMP9 too has been reported to be activated by papillomavirus (Akgül et al, 2006; Behren et al, 2005).…”

“…Additionally, MMP1 was present in much greater amounts than in HaCaT-pCI-neo cells and also in suprabasal layers (Fig. 3l), indicating that the abundant production of MMP1 by the HaCaT-16E5 cells was not only due to the interaction with type I collagen but also predominantly to the effect of E5.E5-induced invasion might substantially contribute to tumour progression in persistently infected cervical epithelial cells, although this remains to be confirmed.The gene for MMP1 is overexpressed in HPV-associated cervical cancer and in BPV-1-associated equine sarcoids (Narayan et al, 2007;Yuan et al, 2008), but the papillomavirus proteins involved in the transcriptional activation of the MMP1 gene in these tumours have not yet been identified. MMP9 too has been reported to be activated by papillomavirus (Akgül et al, 2006; Behren et al, 2005).…”

Upregulation of equine matrix metalloproteinase 1 by bovine papillomavirus type 1 is through the transcription factor activator protein-1

“…Equine MMP-1 and Fra-1 mRNAs were quantified by real-time relative quantification RT-PCR. The relative quantification RT-PCR primer and probe sets for MMP-1 and Fra-1 gene and the housekeeping gene glyceraldehyde 3-phosphate dehydrogenase (GAPDH) have been described previously (Yuan et al, 2008b). Total RNA extraction, cDNA synthesis and PCR conditions were all as described previously (Yuan et al, 2007b).…”

“…The upregulation of endogenous MMP-1 expression by E5 was surprising given the inability of E5 to stimulate the MP0.2 promoter, and suggested either that E5 impacts on the activity of the fulllength MMP-1 promoter or that it upregulates MMP-1 expression by indirect mechanisms (see below). Previously, we found that BPV-1 upregulated the transcriptional expression of Fra-1 (Yuan et al, 2008b). In this study, we examined the expression of phosphorylated (activated) Fra-1 (p-Fra-1) by immunoblotting and immunofluorescence staining using a specific antibody against p-Fra-1.…”

“…Activator protein-1 (AP-1) is the key cellular factor involved in regulation of MMP expression (Lin et al, 1993). Extracellular stimuli including growth factors, cytokines, stress and virus infection can induce MMP expression (Hirata et al, 2003;Lichtinghagen et al, 2003;Pustovrh et al, 2005 We have previously shown that BPV-1 upregulates MMP-1 expression and activity and is essential for the transformation of sarcoid fibroblasts, including invasiveness (Yuan et al, 2008b(Yuan et al, , 2010a. However, it remains unclear how BPV-1 proteins regulate MMP-1 expression.…”