Regulation of Tumor Necrosis Factor Alpha Promoter by Human Parvovirus B19 NS1 through Activation of AP-1 and AP-2

Abstract

Human parvovirus B19 frequently causes acute and chronic arthritis in adults. The molecular mechanism of B19 arthritis, however, remains poorly understood. We previously showed that the transmission of B19 from rheumatoid synoviocytes to monocytic cells is associated with enhanced secretion of tumor necrosis factor alpha (TNF-␣), which triggers inflammation, and interleukin-6. To determine the role of B19 in the production of TNF-␣, we focused on the function of its nonstructural protein, NS1, and established monocytic U937 lines transduced with the NS1 gene under the control of an inducible promoter. Production of TNF-␣ mRNA and protein was elevated in a manner associated with NS1 expression. Reporter assays revealed that AP-1 and AP-2 motifs on the TNF-␣ promoter were responsible for NS1-mediated up-regulation. Electrophoretic mobility shift assay showed specific binding of nuclear proteins from NS1 gene-transduced cells with the AP-1 or AP-2 probe. Antibodies against transcription factors AP-1 and AP-2 and anti-NS1 antibody inhibited the binding of nuclear proteins to the corresponding probes. These data indicate that NS1 up-regulates TNF-␣ transcription via activation of AP-1 and AP-2 in monocytic cells. The molecular mechanisms of NS1-mediated TNF-␣ expression would explain the pathogenesis of B19-associated inflammation.Human parvovirus B19 belongs to the family Parvoviridae and the genus Erythrovirus. The B19 genome includes three major open reading frames coding for the nonstructural protein NS1 in the left half and structural proteins VP1 and VP2 in the right half (44). B19 is the only parvovirus that has been clearly linked with disease in humans. Common manifestations caused by B19 infection include transient aplastic crisis in patients with histories of chronic hemolytic anemia (37), erythema infectiosum (7), nonimmune hydrops fetalis (9), chronic pure red cell aplasia in patients with immunosuppression (24), and arthralgia or arthropathy (59). Acute onset of polyarthritis is common in adults (mostly women) (60). Joint symptoms last for 1 to 3 weeks, although they may persist for months or years. B19 arthritis often meets clinical diagnostic criteria for rheumatoid arthritis and can be erosive (12,19,35,53,59). Because it has been observed that joint symptoms caused by B19 infection coincide with the appearance of specific immunoglobulin G (IgG) and the disappearance of viremia (2) and joint symptoms occur in chronically infected subjects after treatment with immunoglobulin (17), immune complex is thought to cause acute polyarthropathy. However, molecular mechanisms for the involvement of immune complexes in joint inflammation are unclear.Tumor necrosis factor alpha (TNF-␣), a representative proinflammatory cytokine, is an important mediator in the inflammatory process associated with many types of infections and autoimmune diseases through induction of a variety of cytokines, chemokines, and proteases in autocrine and paracrine pathways (16,55). Although various cell types are capable of producing T...

Antibody to parvovirus B19 nonstructural protein is associated with chronic arthralgia in patients with chronic fatigue syndrome/myalgic encephalomyelitis

“…It has been shown to possess sitespecific DNA-binding and helicase activities, and is functionally active as a trans-activator of the viral p6 and various cellular promoters (Gareus et al, 1998;Raab et al, 2001Raab et al, , 2002Vassias et al, 1998), for example, the cellular promoters for the expression of TNF-a and interleukin 6 (Fu et al, 2002;Moffatt et al, 1996). NS1 also contains a well-conserved nucleoside-triphosphate-binding motif, which is essential for a variety of biological functions, such as ATPase activity and cytotoxicity.…”

Human parvovirus B19 causes cell cycle arrest of human erythroid progenitors via deregulation of the E2F family of transcription factors

“…NS1 is a multifunctional protein that is involved in regulation of viral p6 promoter activity, DNA replication (15)(16)(17), cell cycle arrest in G 1 and G 2 phases in erythroid lineage cells (18,19), and initiation of apoptosis (20). NS1 also functions as a transcriptional transactivator, regulating a variety of viral and cellular genes, such as TNFA (21) and p21 WAF1/CIP1 (22). NS1 contains a nucleoside triphosphate-binding motif relating to NS1 cytotoxicity (23).…”

Human Parvovirus B19 Transgenic Mice Become Susceptible to Polyarthritis

“…The secretion of TNF-␣ and IL-6 induced by the coculture of the macrophage cell line, U937, or THP1 with rheumatoid synovial cells was inhibited by coexistence of monoclonal anti-B19 Abs (12). We also showed that transduction of U937 cells with NS-1 gene-activated transcription factors, AP-1 and AP-2, resulted in the up-regulation of TNF-␣ gene expression and secretion of TNF-␣ from host cells (34). This indicates that persistent activation of B19 may constantly up-regulate the TNF-␣ gene in infected cells.…”

“…NS1 is a functional protein of B19 responsible for not only replication of B19 (31), but also activation of host cell genes associated with apoptosis (32) and cytokines (33,34). We have revealed NS1-mediated production of TNF-␣ through activation of AP1 and AP2 (34). The presented data, including an enhanced production of Th1 and Th2 cytokines (Fig.…”

“…These cytokines secreted from activated Th1 cells may induce further activation of Th1 cells and neutrophils, causing progression of inflammation in the joints. NS1 is a functional protein of B19 responsible for not only replication of B19 (31), but also activation of host cell genes associated with apoptosis (32) and cytokines (33,34). We have revealed NS1-mediated production of TNF-␣ through activation of AP1 and AP2 (34).…”