ABSTRACT
miR-126 is a microRNA expressed predominately by endothelial cells and controls angiogenesis. We found miR-126 was required for the innate response to pathogen-associated nucleic acids and that miR-126-deficient mice had greater susceptibility to infection with pseudotyped HIV. Profiling of miRNA indicated that miR-126 had high and specific expression by plasmacytoid dendritic cells (pDCs). Moreover, miR-126 controlled the survival and function of pDCs and regulated the expression of genes encoding molecules involved in the innate response, including Tlr7, Tlr9 and Nfkb1, as well as Kdr, which encodes the growth factor receptor VEGFR2. Deletion of Kdr in DCs resulted in reduced production of type I interferon, which supports the proposal of a role for VEGFR2 in miR-126 regulation of pDCs. Our studies identify the miR-126-VEGFR2 axis as an important regulator of the innate response that operates through multiscale control of pDCs.
Subject(s)
Dendritic Cells/immunology , Immunity, Innate/immunology , MicroRNAs/immunology , Vascular Endothelial Growth Factor Receptor-2/immunology , Animals , Dendritic Cells/metabolism , Flow Cytometry , HIV Infections/immunology , HIV Infections/virology , Humans , Immunity, Innate/genetics , Immunoblotting , Interferon-alpha/blood , Interferon-alpha/immunology , Interferon-alpha/metabolism , Mice , Mice, Knockout , Mice, Transgenic , MicroRNAs/genetics , MicroRNAs/metabolism , NF-kappa B p50 Subunit/genetics , NF-kappa B p50 Subunit/immunology , NF-kappa B p50 Subunit/metabolism , Nucleic Acids/immunology , Nucleic Acids/metabolism , Oligodeoxyribonucleotides/genetics , Oligodeoxyribonucleotides/immunology , Oligonucleotide Array Sequence Analysis , Reverse Transcriptase Polymerase Chain Reaction , Toll-Like Receptor 7/genetics , Toll-Like Receptor 7/immunology , Toll-Like Receptor 7/metabolism , Toll-Like Receptor 9/genetics , Toll-Like Receptor 9/immunology , Toll-Like Receptor 9/metabolism , Transcriptome/immunology , Vascular Endothelial Growth Factor Receptor-2/genetics , Vascular Endothelial Growth Factor Receptor-2/metabolismABSTRACT
PURPOSE: Bisphosphonates (BPs) are a widely used class of drugs that are effective in the treatment and prevention of osteoporosis, hypercalcemia of malignancy, and bone metastases associated with multiple myeloma, breast cancer, and other solid tumors. In the past several years there have been numerous reports describing the occurrence of osteonecrosis of the jaws (ONJ) associated with these drugs. Whether the ONJ lesion initiates in the oral mucosa or derives from the underlying bone is not well understood. In this report we describe the effect of pamidronate, a second-generation BP, on oral mucosal cells. MATERIALS AND METHODS: Murine oral keratinocytes were isolated and exposed to pamidronate at a range of clinically relevant doses. Cellular proliferation was measured using a MTS/PMS reagent-based kit and wound healing was examined with a scratch assay. To determine whether oral keratinocytes undergo apoptosis following exposure to pamidronate, TUNEL, caspase-3, and DAPI apoptosis assays were performed. RESULTS: We show that BP pretreatment of oral mucosal cells inhibits proliferation and wound healing at clinically relevant doses, and that this inhibition is not due to cellular apoptosis. CONCLUSIONS: To our knowledge this is the first report investigating the effect of nitrogen-containing BPs on oral mucosal cells. This study suggests that BPs inhibit oral keratinocyte wound healing which may play a significant role in the initiation of ONJ.