Tomomi Aizawa's research while affiliated with Hirosaki University and other places

Background In addition to regulating the antiviral response, increased expression of Toll-like receptor 3 (TLR3) in resident renal cells plays a role in developing some forms of glomerulonephritis. TLR3 activation leads to type I interferon (IFN) production, which induces the expression of IFN-stimulated genes (ISGs). However, the role of ISG20 expression in resident renal cells remains unclear. Methods Cultured normal human glomerular endothelial cells (GECs) were treated with polyinosinic-polycytidylic acid (poly IC), Escherichia coli lipopolysaccharide (LPS), R848, and CpG (TLR3, TLR4, TLR7, and TLR9 agonists, respectively). The mRNA levels of ISG20, CX3CL1/fractalkine, and CXCL10/IP-10 were measured by quantitative reverse transcription-polymerase chain reaction. ISG20 protein expression was assessed by Western blotting. RNA interference was used to knockdown IFN-β and ISG20 expression. CX3CL1 protein levels were assessed by enzyme-linked immunosorbent assay. We performed immunofluorescence to examine endothelial ISG20 expression in biopsy specimens from patients with lupus nephritis (LN). Results In GECs, the expression of ISG20 mRNA and protein was increased by polyIC, not by LPS, R848, or CpG treatment. Moreover, ISG20 knockdown prevented poly IC-induced CX3CL1 expression but had no effect on CXCL10 expression. Intense endothelial ISG20 immunoreactivity was observed in biopsy specimens obtained from patients with proliferative LN. Conclusion In GECs, ISG20 was regulated via TLR3 but not via TLR4, TLR7, or TLR9 signaling. Moreover, ISG20 was involved in regulating CX3CL1 production. In addition to regulating antiviral innate immunity, ISG20 may act as a mediator of CX3CL1 production, thereby inducing glomerular inflammation, particularly in patients with LN.

Background: Besides regulating the antiviral response, increased expression of Toll-like receptor 3 (TLR3) in resident renal cells plays a role in the development of some forms of glomerulonephritis. TLR3 activation leads to the production of type I interferon (IFN), which subsequently induces the expression of IFN-stimulated genes (ISGs). We previously reported that in glomerular resident cells, ISG20 expression is regulated via TLR3/ IFN-β signaling, however, its detailed implications remain undetermined. Methods: Cultured normal human glomerular endothelial cells (GECs) were treated with polyinosinic polycytidylic acid (poly-IC), Escherichia coli lipopolysaccharide (LPS), R848, and CpG (TLR3, TLR4, TLR7, and TLR9 agonists). ISG20, CX3CL1/fractalkine and CXCL10/IP-10 mRNA levels were analyzed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). ISG20 protein expression was evaluated by western blotting. RNA interference (siRNA) was used to knockdown IFN-β and ISG20. CX3CL1 protein levels were evaluated by enzyme-linked immunosorbent assay (ELISA). Results: In GECs, the expression of ISG20 mRNA and protein was increased by poly-IC but not by LPS, R848, or CpG treatment. siRNA-mediated knockdown of IFN-β inhibited the poly-IC-induced ISG20 expression. Moreover, ISG20 knockdown prevented the poly-IC-induced expression of CX3CL1, a representative chemokine that acts as a strong macrophage chemoattractant, whereas it had no effect on CXCL10 expression. Conclusion: In GECs, ISG20 is regulated via TLR3 but not via TLR4, TLR7, or TLR9 signaling, and ISG20 is involved in regulating CX3CL1 production. Besides regulating antiviral innate immunity, ISG20 may act as a mediator of CX3CL1 production, thereby inducing glomerular inflammation. Thus, modulating ISG20 expression might be a possible therapeutic strategy for glomerulonephritis.

Background: Besides regulating antiviral response, increased expression of Toll-like receptor 3 (TLR3) in resident renal cells plays a role in the development of some forms of glomerulonephritis. TLR3 activation leads to the production of type I interferon (IFN), which subsequently induces the expression of IFN-stimulated genes (ISGs). We previously reported that in glomerular resident cells, ISG20 expression is regulated via the TLR3/ IFN-β signaling, however, its detailed implications remain undetermined. Methods: Cultured normal human glomerular endothelial cells (GECs) were treated with polyinosinic-polycytidylic acid (poly IC), Escherichia coli lipopolysaccharide (LPS), R848, and CpG (TLR3, TLR4, TLR7, and TLR9 agonists). ISG20, CX3CL1/fractalkine and CXCL10/IP-10 mRNA levels were analyzed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). ISG20 protein expression was evaluated by western blotting. RNA interference (siRNA) was used to knockdown IFN-β and ISG20. CX3CL1 protein levels were evaluated by enzyme-linked immunosorbent assay (ELISA). Results: In GECs, the expression of ISG20 mRNA and protein was increased by poly IC but not by LPS, R848, or CpG treatment. siRNA-mediated knockdown of IFN-β inhibited the poly IC-induced ISG20 expression. Moreover, ISG20 knockdown prevented the poly IC-induced expression of CX3CL1, a representative chemokine that acts as a strong macrophage chemoattractant, whereas it had no effect on CXCL10 expression. Conclusion: In GECs, ISG20 is regulated via TLR3 but not via TLR4, TLR7, or TLR9 signaling, and ISG20 is involved in regulating CX3CL1 production. Besides regulating the antiviral innate immunity, ISG20 may act as a mediator of CX3CL1 production, thereby inducing glomerular inflammation. Thus, modulating ISG20 expression might be a possible therapeutic strategy for glomerulonephritis.

Background Sustained type I interferon (IFN) activation via Toll-like receptor (TLR) 3, 7 and 9 signaling has been reported to play a pivotal role in the development of lupus nephritis (LN). Although type I IFN activation has been shown to induce interferon-stimulated genes (ISGs) expression in systemic lupus erythematosus, the implication of ISGs expression in intrinsic glomerular cells remains largely unknown. Methods We treated cultured human glomerular endothelial cells (GECs) with polyinosinic-polycytidylic acid (poly IC), R848, and CpG (TLR3, TLR7, and TLR9 agonists, respectively) and analyzed the expression of DExD/H-Box Helicase 60 (DDX60), a representative ISG, using quantitative reverse transcription-polymerase chain reaction and western blotting. Additionally, RNA interference against IFN-β or DDX60 was performed. Furthermore, cleavage of caspase 9 and poly (ADP-ribose) polymerase (PARP), markers of cells undergoing apoptosis, was examined using western blotting. We conducted an immunofluorescence study to examine endothelial DDX60 expression in biopsy specimens from patients with LN. Results We observed that endothelial expression of DDX60 was induced by poly IC but not by R848 or CpG, and RNA interference against IFN-β inhibited poly IC-induced DDX60 expression. DDX60 knockdown induced cleavage of caspase 9 and PARP. Intense endothelial DDX60 expression was observed in biopsy specimens from patients with diffuse proliferative LN. Conclusion Glomerular endothelial DDX60 expression may prevent apoptosis, which is involved in the pathogenesis of LN. Modulating the upregulation of the regional innate immune system via TLR3 signaling may be a promising treatment target for LN.

Aseptic meningitis sometimes occurs as consequence of central nervous system (CNS) involvement in patients with primary Sjögren’s syndrome (SS), even in pediatric-onset cases. However, little information is available regarding the pathological role of CSF anti-Ro/SSA and anti-La/SSB antibodies in the CNS involvement in patients with primary SS. We experienced an 18-year-old adolescent female with a 7-year history of suspicious of subclinical SS who subsequently developed aseptic meningitis as initial presentation of probable SS. Her CSF exhibited marked elevation of anti-Ro/SSA and anti-La/SSB antibodies. When compared to her CSF IgG/serum IgG ratio (0.0058), her CSF/serum ratios of anti-Ro/SSA and anti-La/SSB antibody titers were higher (0.448 and 0.068, respectively; these were 77.5 and 11.7 times higher than that of IgG, respectively), suggesting that regional production of these antibodies was attributable, at least partly, to the development of meningitis. After the initiation of prednisolone treatment, her clinical manifestations promptly subsided. Since the clinical and pathological roles of the Ro/SSA antibody system in several autoimmune conditions have been postulated, our clinical observation may add novel insight to this theory.

Background Dysregulation of the coagulation fibrinolysis system in resident glomerular cells is associated with the pathogenesis of lupus nephritis (LN). However, the role of plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (tPA) in resident glomerular cells remains undetermined. Methods we examined the expression of PAI-1 and tPA mRNA in cultured normal human glomerular endothelial cells (GECs) treated with serum from patients with systemic lupus erythematosus (SLE) using quantitative reverse transcription polymerase chain reaction. Furthermore, we determined the relationship between PAI-1/tPA mRNA expression and several clinical/laboratory parameters. Serum from 16 patients (9 patients with new-onset SLE and 7 patients with stable SLE) was used in the study. Results PAI-1 and tPA mRNA expression was significantly higher in GECs treated with serum of patients with new-onset SLE than other groups. In addition, PAI-1 and tPA mRNA levels were significantly correlated in GECs treated with serum from patients with SLE. Interestingly, both PAI-1 and tPA mRNA level in GECs were inversely correlated with serum C4 level and positively correlated with SLE disease activity. Conclusions These results suggest that serum from patients with SLE may activate the fibrinolysis system in glomerulus, which may be involved in the pathogenesis of LN.