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Changes in the biosynthesis of glycosaminoglycans in polymorphonuclear leukocytes in relation to their induction into
Abstract:
The synthesis and function of dermatan sulfate in peritoneal polymorphonuclear (PMN) leukocytes were studied. The peritoneal PMN leukocytes were obtained at 4,8, and 16 h after guinea pigs were injected intraperitoneally with caseinate solution, and were incubated with [35S] sulfate or [3H] glucosamine on plastic. The total glycosaminoglycan synthesis and the proportion of dermatan sulfate to total glycosaminoglycans linearly increased with time. In order to clarify the function of the increased dermatan sulfate, peritoneal PMN leukocytes were cultured with [35S] sulfate on plastic or collagen gel. The total glycosaminoglycan synthesis on the collagen gel culture increased 1.5 times compared with that on the plastic culture, and especially, dermatan sulfate synthesis increased twofold. In addition, 65% of dermatan sulfate on the collagen gel culture was found in the cell and the collagenase-soluble fractions. These results indicate that proteodermatan sulfate synthesized by PMN leukocytes interacts with collagen in vitro, and suggest that PMN leukocytes, which migrated to the inflammatory locus, lastly adhere to the injured tissue through the interaction of proteodermatan sulfate synthesized by themselves with collagen fibers exposed in the inflammatory locus.
Insights
Polymorphonuclear leukocytes synthesize increasing amounts of dermatan sulfate during inflammation. This proteodermatan sulfate interacts with collagen, potentially mediating leukocyte adhesion to injured tissues.
Area of Science:
- Biochemistry
- Cell Biology
- Immunology
Background:
- Polymorphonuclear (PMN) leukocytes play a critical role in inflammatory responses.
- The synthesis and function of glycosaminoglycans, such as dermatan sulfate, in PMN leukocytes are not fully understood.
Purpose of the Study:
- To investigate the synthesis and functional role of dermatan sulfate in peritoneal PMN leukocytes.
- To explore the interaction of synthesized dermatan sulfate with collagen.
Main Methods:
- Peritoneal PMN leukocytes were isolated from guinea pigs at various time points after caseinate injection.
- Cells were incubated with radiolabeled sulfate or glucosamine to measure glycosaminoglycan synthesis.
- Leukocyte cultures were performed on plastic and collagen gel substrates to assess interactions.
Main Results:
- Dermatan sulfate synthesis and its proportion to total glycosaminoglycans increased over time in PMN leukocytes.
- Culturing PMN leukocytes on collagen gel significantly enhanced glycosaminoglycan and dermatan sulfate synthesis compared to plastic.
- A substantial portion of synthesized dermatan sulfate was found associated with cells and collagenase-soluble fractions when cultured on collagen gel.
Conclusions:
- PMN leukocytes synthesize proteodermatan sulfate that interacts with collagen in vitro.
- This interaction suggests a mechanism for PMN leukocyte adhesion to collagen fibers at inflammatory sites.
- Proteodermatan sulfate may mediate the final adhesion of leukocytes to injured tissues during inflammation.