The attenuation of cockroach allergy by DNA vaccine encoding cockroach allergen Bla g 2.

Bla g 2 is one of the most potent cockroach allergens. No effective treatment or vaccination strategies are yet available. We evaluated the prophylactic efficacy of Bla g 2 DNA vaccination in a mouse model of allergic airway inflammation. C57/BL6 mice were given Bla g 2 DNA vaccine prior to sensitization with recombinant Bla g 2 (rBla g 2) antigens, followed by nebulized rBla g 2 challenge. Bla g 2 vaccine could express at both transcriptional and translational levels in mammalian cells. Moreover, Bla g 2 vaccine significantly reduced the total inflammatory cell infiltrate and eosinophilia in bronchoalveolar lavage fluid, and markedly decreased allergen-induced inflammatory infiltrates in the lungs and Bla g 2-specific IgE in serum upon challenge with rBla g 2. Importantly, Bla g 2 vaccine could induce the production of antigen-specific IFN-γ and downregulated Th2 pro-inflammatory cytokines IL-4, IL-5, and IL-13. Thus, DNA vaccination showed protective efficacy against a clinically relevant allergen, Bla g 2.

Induction of multiple matrix metalloproteinases in human dermal and synovial fibroblasts by Staphylococcus aureus: implications in the pathogenesis of septic arthritis and other soft tissue infections.

Infections of body tissue by Staphylococcus aureus are quickly followed by degradation of connective tissue. Patients with rheumatoid arthritis are more prone to S. aureus-mediated septic arthritis. Various types of collagen form the major structural matrix of different connective tissues of the body. These different collagens are degraded by specific matrix metalloproteinases (MMPs) produced by fibroblasts, other connective tissue cells, and inflammatory cells that are induced by interleukin-1 (IL-1) and tumor necrosis factor (TNF). To determine the host's contribution in the joint destruction of S. aureus-mediated septic arthritis, we analyzed the MMP expression profile in human dermal and synovial fibroblasts upon exposure to culture supernatant and whole cell lysates of S. aureus. Human dermal and synovial fibroblasts treated with cell lysate and filtered culture supernatants had significantly enhanced expression of MMP-1, MMP-2, MMP-3, MMP-7, MMP-10, and MMP-11 compared with the untreated controls (p < 0.05). In the S. aureus culture supernatant, the MMP induction activity was identified to be within the molecular-weight range of 30 to >50 kDa. The MMP expression profile was similar in fibroblasts exposed to a combination of IL-1/TNF. mRNA levels of several genes of the mitogen-activated protein kinase (MAPK) signal transduction pathway were significantly elevated in fibroblasts treated with S. aureus cell lysate and culture supernatant. Also, tyrosine phosphorylation was significantly higher in fibroblasts treated with S. aureus components. Tyrosine phosphorylation and MAPK gene expression patterns were similar in fibroblasts treated with a combination of IL-1/TNF and S. aureus. Mutants lacking staphylococcal accessory regulator (Sar) and accessory gene regulator (Agr), which cause significantly less severe septic arthritis in murine models, were able to induce expression of several MMP mRNA comparable with that of their isogenic parent strain but induced notably higher levels of tissue inhibitors of metalloproteinases (TIMPs). To our knowledge, this is the first report of induction of multiple MMP/TIMP expression from human dermal and synovial fibroblasts upon S. aureus treatment. We propose that host-derived MMPs contribute to the progressive joint destruction observed in S. aureus-mediated septic arthritis.

Novel functions of intracellular IL-1ra in human dermal fibroblasts: implications in the pathogenesis of fibrosis.

Intracellular IL-1 receptor antagonist (icIL-1ra) is reportedly involved in functions independent of blocking IL-1 receptor signaling. Fibroblasts derived from the involved skin of patients with systemic sclerosis (SSc) are predominantly of the myofibroblast phenotype, with higher levels of icIL-1ra compared to normal skin fibroblasts. We examined the effect of overexpression of icIL-1ra on the phenotype and function of normal fibroblasts with respect to the expression of alpha smooth muscle actin (alpha-SMA), a specific marker for myofibroblasts, and plasminogen activator inhibitor (PAI), a protein involved in fibrogenesis and expressed at higher levels in myofibroblasts, and the production of collagenase (matrix metalloproteinase-1 (MMP-1)), the major enzyme involved in the degradation of native collagen in the skin. Normal human foreskin fibroblasts overexpressing icIL-1ra showed higher levels of alpha-SMA and PAI and had lower levels of collagenase and MMP-1 mRNA induced by inflammatory cytokines. By contrast, levels of mRNA for tissue inhibitor of metalloproteinase-1 in the transfected cells were not different from the control cells. Pretreatment of the ic-IL-1ra-transfected cells with antisense oligonucleotide directed against the mRNA of icIL-1ra restored MMP-1 expression induced by stimulation with IL-1beta. Our data indicate novel functions for icIL-1ra, which might be relevant to the genesis of fibrotic diseases such as SSc.

Modulation of TNF-alpha gene expression by IFN-gamma and pamidronate in murine macrophages: regulation by STAT1-dependent pathways.

Aminobisphosphonates are drugs used in the treatment of hypercalcemia, Paget's disease, osteoporosis, and malignancy. Some patients treated with aminobisphosphonates have a transient febrile reaction that may be caused by an increased serum concentration of proinflammatory cytokines. Aminobisphosphonates induce the production of certain proinflammatory cytokines in vitro, especially in cells of monocytic lineage. A unique feature of aminobisphosphonates is that they bind the Vgamma2Vdelta2 class of T cells, which are found only in primates, and stimulate cytokine production. The effects of aminobisphosphonates on other cells, including macrophages, are incompletely understood. We show in this study that treatment of murine macrophages with pamidronate, a second generation aminobisphosphonate, induces TNF-alpha production. Furthermore, pretreatment of murine macrophages with pamidronate before stimulation with IFN-gamma significantly augments IFN-gamma-dependent production of TNF-alpha. This pamidronate-mediated augmentation of TNF-alpha production results in sustained phosphorylation of the tyrosine residue at position 701 of STAT1 after IFN-gamma treatment. Our data suggest that this sustained phosphorylation results from inhibition of protein tyrosine phosphatase activity. We also show that pamidronate treatment increases TNF-alpha production in vivo in mice. Pamidronate-augmented TNF-alpha production by macrophages might be a useful strategy for cytokine-based anticancer therapy.

Cellular origins of fibroblasts: possible implications for organ fibrosis in systemic sclerosis.

PURPOSE OF REVIEW: There is an intense interest in the potential of circulating blood cells and epithelium-related nonfibroblast cells to change into matrix synthesizing fibroblasts and myofibroblasts. These sources of fibroblasts may have importance in systemic sclerosis (scleroderma). RECENT FINDINGS: Epithelial cells from different sources can transition into fibroblasts and myofibroblasts in response to transforming growth factor beta and other growth factors/cytokines. This is called epithelial-mesenchymal transition (EMT). EMT has been repeatedly demonstrated to occur in several models of renal fibrosis including lupus prone mice. Quite unexpectedly, bone morphogenic protein 7 prevents EMT and protects lupus mice and other renal fibrosis models from developing fibrosis in the kidneys. Human peripheral blood mononuclear cells under different conditions of culture give rise to several different types of fibroblast-like cells. In SSc, it has been observed that the sera have low levels of serum amyloid protein. Serum amyloid protein has been found to inhibit the generation of fibrocytes from CD14 precursors. The implications of these potential sources of fibroblasts and myofibroblasts in systemic sclerosis and related rheumatic diseases are discussed. SUMMARY: Fibroblasts and myofibroblasts in skin and internal organs of patients with systemic sclerosis and related diseases may possibly arise not only from the resident fibroblast population but from epithelial cells, pericytes, monocytes, and other progenitors from the circulating pool of hematopoietic cells and stem cells. These alternative sources of fibroblasts would best be treated by specifically targeting the transition or transdifferentiation process by which cells change into fibroblasts.