Studies on the formation mechanism and functions of the covalently bound complex of hyaluronan with SHAP, the functional molecular entity of hyaluronan

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The covalently bound complex formed from inter-α-trypsin inhibitor (ITI) and hyaluronan (HA) by transesterification reaction, the SHAP (ITI heavy chain)-HA complex was investigated with regard to its physiological functions and serum enz; yme factors involved in the reaction. The candidate protein obtained from one of the library of serum fractions by the beforehand establisehd purification methods using a series of affinity columns was identified FHR-1 (factor H-related protein-1). However, the medium fraction of FHR-1 cDNA-transfected hepatocarcinoma HLF cells did not show any of the activity. Meanwhile, we found that the medium of the transfectants with cDNA of TSG-6 (TNFα-stimulated gene 6 product) had the dramatically increased activity that was yet retained after removal of TSG-6 by passing through the antibody affinity column, suggesting that the enzyme factors could not be TSG-6 itself and be induced with TSG-6 in the cells. Thus, we are now in the processes to the purification … More and identification of the factors. We previously developed the bikunin (ITI short chain)-knockout mouse system in order to investigate in vivo functions of the SHAP-HA complex where the complex was not formed. We found that the knockout mouse was resistant to the induction of acute hepatitis by the administration of D-galactosamine/E.coli lipopolysaccharide (LPS) in which the CD44-HA interaction-dependent attachment of neutrophils to live capillary sinusoidal cell surfaces was involved in response to the LPS stimuli. We then found using culthred leukocytes that the SHAP-HA complex activates the CD44-HA interaction-dependent cell adhesion more than 100 times, which is a decisive evidence for the involvement of the SHAP-HA complex in inflammatory cell response. We also found the good relationship between the SHAP-HA complex levels and the disease progression in the serum samples from patients of liver diseases, articular cartilage injury, gestoses, ovarian cancer etc, suggesting functional significances of the SHAP-HA complex in those diseases and the high reliability of the complex as a disease marker. Less