Wlodzimierz Maslinski

Effective photoimmunotherapy of murine colon carcinoma induced by the combination of photodynamic therapy and dendritic cells.

Purpose: The unique mechanism of tumor destruction by photodynamic therapy (PDT), resulting from apoptotic and necrotic killing of tumor cells accompanied by local inflammatory reaction and induction of heat shock proteins (HSPs), prompted us to investigate the antitumor effectiveness of the combination of PDT with administration of immature dendritic cells (DCs). Experimental Design: Confocal microscopy and Western blotting were used to investigate the influence of PDT on the induction of apoptosis and expression of HSP expression in C-26 cells. Confocal microscopy and flow cytometry studies were used to examine phagocytosis of PDT-treated C-26 cells by DCs. Secretion of interleukin (IL)-12 was measured with ELISA. Cytotoxic activity of lymph node cells was evaluated in a standard 51Cr-release assay. The antitumor effectiveness of PDT in combination with administration of DCs was investigated in in vivo model. Results: PDT treatment resulted in the induction of apoptotic and necrotic cell death and expression of HSP27, HSP60, HSP72/73, HSP90, HO-1, and GRP78 in C-26 cells. Immature DCs cocultured with PDT-treated C-26 cells efficiently engulfed killed tumor cells, acquired functional features of maturation, and produced substantial amounts of IL-12. Inoculation of immature DCs into the PDT-treated tumors resulted in effective homing to regional and peripheral lymph nodes and stimulation of cytotoxic activity of T and natural killer cells. The combination treatment with PDT and administration of DCs produced effective antitumor response. Conclusions: The feasibility and antitumor effectiveness demonstrated in these studies suggest that treatment protocols involving the administration of immature DCs in combination with PDT may have clinical potential.

Inhibitor of DNA binding/differentiation 2 induced by hypoxia promotes synovial fibroblast–dependent osteoclastogenesis

OBJECTIVE To map hypoxic areas in arthritic synovium and to establish the relevance of low oxygen levels to the phenotype of synovial fibroblasts, with special focus on bone degradation. METHODS To analyze the distribution of hypoxia in arthritic joints, the hypoxia marker EF5 was administered to mice with collagen-induced arthritis (CIA). To evaluate the effect of hypoxia on rheumatoid arthritis synovial fibroblasts (RASFs), reverse suppression subtractive hybridization and complementary DNA array were used. Real-time polymerase chain reaction, Western blotting, and immunohistochemistry were used to evaluate the expression of inhibitor of DNA binding/differentiation 2 (ID-2). To investigate the function of ID-2 in RASFs, cells were transfected either with ID-2 vector or with ID-2-specific small interfering RNA. RESULTS EF5 staining showed the presence of hypoxia in arthritic joints, particularly at sites of synovial invasion into bone. Differential expression analysis revealed that ID-2 was strongly induced by hypoxia in RASFs. Immunohistochemical analysis of CIA mouse synovium and human RA synovium showed a strong expression of ID-2 by RASFs at sites of synovial invasion into bone. Overexpression of ID-2 in RASFs significantly induced the expression of several factors promoting osteoclastogenesis. The biologic relevance of the potent osteoclastogenesis-promoting effects was shown by coculture assays of ID-2-overexpressing RASFs with bone marrow cells, leading to an increased differentiation of osteoclasts from bone marrow precursors. CONCLUSION The data show that hypoxic conditions are present at sites of inflammation and synovial invasion into bone in arthritic synovium. Hypoxia-induced ID-2 may contribute to joint destruction in RA patients by promoting synovial fibroblast-dependent osteoclastogenesis.

The role of microRNA-5196 in the pathogenesis of systemic sclerosis.

Systemic sclerosis (SSc) is a chronic autoimmune disease characterised by tissue fibrosis and immune abnormalities. Recent evidence suggests that activated circulating monocytes from patients with SSc play an important role in early stages of SSc pathogenesis due to enhanced expression of tissue inhibitor of metalloproteinases 1 (TIMP‐1), IL‐8 and reactive oxygen species (ROS) induction. However, the exact factors that contribute to chronic inflammation and subsequently fibrosis progression are still unknown.

Distinct lymphocyte subpopulations in bone marrow from rheumatoid arthritis and osteoarthritis patients: a role for IL-15?

Recent data indicate that bone marrow plays an important role not only as a primary lymphoid organ responsible for haemopoiesis, but also as a secondary lymphoid organ with capability of antigen presentation exceeding that of lymph nodes. Although in chronic inflammatory/immune disease, like rheumatoid arthritis (RA), bone marrow participates in the initiation and/or perpetuation of the disease, there is little information about the real number of lymphocyte subpopulations in bone marrow of these patients and how they can be modulated by T-cell growth factors. IL-15 acting through IL-15 receptors (including the high-affinity IL-15R alpha chain) is a key cytokine influencing the development of natural killer cells in bone marrow, and proliferation and maintenance of the memory T-cell pool. However, there is no information about the levels of IL-15 in bone marrow.