The overall objective of this proposed research is to further characterize the mechanisms of production, and the possible influences on cell function, of two structural variants of the specific IL-1 receptor antagonist (IL-1ra)found inside cells. The first form of this molecule, termed secretory or slL-1ra, is a major extracellular product of monocytes, macrophages and neutrophils. The second form is iclL-1ra, an intracellular molecule found in keratinocytes and other epithelial cells. We have now determined that iclL-1ra is also a major product of synovial fibroblasts and is synthesized in a delayed fashion by monocytes and macrophages. In recent studies, we have observed that a 16kD low molecular weight form of IL-1ra is present in considerable amounts in monocytes, macrophage cell lines and neutrophils. The terminology for this unique family of molecules has been expanded to: slL-1ra, iclL- 1ra(1)(the original cytosolic form), and iclL-1ra(2) (the new low molecular weight cytosolic form). The hypothesis to be examined is that the production of two intracellular forms of IL-1ra by human monocytes, macrophages, fibroblasts and keratinocytes, may involve unique transcriptional or transnational mechanisms in comparison to slL-1ra production by mononuclear phagocytes or fibroblasts. The presence of iclL-1ra(1) or iclL-1ra(2) inside cells may influence the regulation of lL-1 receptor expression or particular lL-1-induced biological responses.
Three specific aims will be addressed in these studies: 1) To determine the mechanisms of regulation of production of iclL-1ra(1). 2) To determine mechanisms of regulation of production of iclL-1ra(2). 3) To determine the influence of structural variants of lL-1ra found inside cells on regulation of lL-1 receptor expression or on specific lL-1 induced biological responses. These studies will utilize the techniques of polymerase chain reaction and primers for lL-1ra, specific ELISA, transfection, morphological approaches, and equilibrium binding. These studies are related to human joint and skin diseases where inflammatory effects of lL-1 are important in pathophysiology. L-1ra may not only inhibit binding of lL-1 to extracellular receptors, but the intracellular structural variants of this molecule may decrease lL-1 effects through influencing receptor expression or initiation of signals. The proposed studies will further determine the mechanisms of production to specific functions of the cell. A greater understanding of the physiology and effects of lL-1ra should result in unique and novel ways to approach the treatment of patients with acute and chronic arthritis or skin diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
2R01AR040135-04A1
Application #
2079857
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1990-08-31
Project End
1999-03-31
Budget Start
1994-04-10
Budget End
1995-03-31
Support Year
4
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of Colorado Denver
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
065391526
City
Aurora
State
CO
Country
United States
Zip Code
80045
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Palmer, Gaby; Talabot-Ayer, Dominique; Szalay-Quinodoz, Ildiko et al. (2003) Mice transgenic for intracellular interleukin-1 receptor antagonist type 1 are protected from collagen-induced arthritis. Eur J Immunol 33:434-40
Banda, Nirmal K; Kraus, Damian; Vondracek, Andrea et al. (2002) Mechanisms of effects of complement inhibition in murine collagen-induced arthritis. Arthritis Rheum 46:3065-75
Arend, W P (2001) The innate immune system in rheumatoid arthritis. Arthritis Rheum 44:2224-34
Gabay, C; Marinova-Mutafchieva, L; Williams, R O et al. (2001) Increased production of intracellular interleukin-1 receptor antagonist type I in the synovium of mice with collagen-induced arthritis: a possible role in the resolution of arthritis. Arthritis Rheum 44:451-62
Arend, W P (2001) Physiology of cytokine pathways in rheumatoid arthritis. Arthritis Rheum 45:101-6
Gabay, C; Gigley, J; Sipe, J et al. (2001) Production of IL-1 receptor antagonist by hepatocytes is regulated as an acute-phase protein in vivo. Eur J Immunol 31:490-9

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