ABSTRACT
Chemokines produced by synoviocytes of the subacromial bursa are up-regulated in subacromial bursitis and rotator cuff disease. We hypothesized that SDF-1α production in bursal synoviocytes may be induced by local cytokines such as interleukin IL-1ß and IL-6. Subacromial bursa specimens were obtained from patients undergoing shoulder surgery. Bursal specimens were stained with anti-human antibodies to IL-1, IL-6, and SDF-1α by immunohistochemistry and compared to normal and rheumatoid controls. Bursal cells were also isolated from specimens and cultured. Early passaged cells were then treated with cytokines (IL-1ß and IL-6) and SDF-1α expression was measured by ELISA and RT-PCR. SDF-1α, IL-1ß, and IL-6 were expressed at high levels in bursitis specimens from human subacromial bursa compared to normal controls. In cultured bursal synoviocytes, there was a dose-dependent increase in SDF-1α production in the supernatants of cells treated with IL-1ß. SDF-1α mRNA expression was also increased in bursal cells treated with IL-1ß. IL-6 caused a minimal but not statistically significant increase in SDF-1α expression. SDF-1α, IL-1ß, and IL-6 are expressed in the inflamed human subacromial bursal tissues in patients with subacromial bursitis. In cultured bursal synoviocytes, SDF-1α gene expression and protein production are stimulated by IL-1ß. IL-1ß produced by bursal syvoviocytes and inflammatory cells in the human subacromial bursa is an important signal in the inflammatory response that occurs in subacromial bursitis and rotator cuff disease.
Subject(s)
Bursa, Synovial/immunology , Bursitis/immunology , Chemokine CXCL12/immunology , Interleukin-1beta/immunology , Rotator Cuff/immunology , Shoulder Impingement Syndrome/immunology , Biopsy , Bursa, Synovial/drug effects , Bursa, Synovial/pathology , Bursitis/pathology , Bursitis/physiopathology , Cells, Cultured , Chemokine CXCL12/genetics , Chemokine CXCL12/metabolism , Gene Expression/immunology , Humans , Immunohistochemistry , Interleukin-1beta/pharmacology , Interleukin-6/immunology , Interleukin-6/pharmacology , Rotator Cuff/pathology , Shoulder Impingement Syndrome/pathology , Shoulder Impingement Syndrome/physiopathology , Synovial Membrane/drug effects , Synovial Membrane/immunology , Synovial Membrane/pathology , Up-Regulation/drug effects , Up-Regulation/immunologyABSTRACT
It has been reported that the diaryl urea class of p38alpha inhibitors binds to p38 map kinase with both high affinity and slow binding kinetics (Pargellis et al. Nat. Struct. Biol. 2002, 9, 268-272). The slow binding kinetics of this class of inhibitors is believed to be the result of binding to an allosteric pocket adjacent to the p38alpha active site. The use of traditional kinetic and equilibrium methods to measure the binding affinity of this class of compounds has created many challenges for determination of structure-activity relationships (SAR). The thermal denaturation method provides a means of measuring high-affinity interactions. In this paper, the method of thermal denaturation will be described as it has been applied to the diaryl urea class of p38 map kinase inhibitors.
