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In vivo degradation of bacterial cell wall by the muralytic enzyme mutanolysin
Abstract:
The muralytic enzyme mutanolysin can act in vivo to eliminate chronic erosive arthritis induced in rats by polymers of peptidoglycan-polysaccharide isolated from group A streptococci (PG-APS). The amounts of PG-APS in the livers and spleens of rats treated with mutanolysin were significantly reduced compared with the amounts in control rats treated with phosphate-buffered saline. However, the amounts of PG-APS in the limbs of mutanolysin- and phosphate-buffered saline-treated rats were comparable. PG-APS polymers extracted from the livers, spleens, and limbs of mutanolysin-treated rats were extensively degraded, whereas PG-APS extracted from phosphate-buffered saline-treated rats had a high molecular weight. We propose that mutanolysin abrogates arthritis in rats by degrading PG-APS polymers to a size which is no longer able to induce chronic erosive arthritis, even though the polymers are still present in the limbs.
Insights
The muralytic enzyme mutanolysin effectively treats chronic erosive arthritis in rats by degrading peptidoglycan-polysaccharide (PG-APS) polymers. This degradation prevents PG-APS from inducing arthritis, even when present in affected limbs.
Area of Science:
- Immunology
- Microbiology
- Biochemistry
Background:
- Chronic erosive arthritis can be induced by polymers of peptidoglycan-polysaccharide (PG-APS) from group A streptococci.
- Understanding the mechanism of PG-APS-induced arthritis is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the efficacy of the muralytic enzyme mutanolysin in eliminating PG-APS-induced chronic erosive arthritis in a rat model.
- To elucidate the mechanism by which mutanolysin exerts its therapeutic effect.
Main Methods:
- Rats were induced with chronic erosive arthritis using PG-APS polymers.
- Mutanolysin or phosphate-buffered saline (control) was administered to the rats.
- PG-APS levels and molecular weight were analyzed in various tissues (livers, spleens, limbs).
Main Results:
- Mutanolysin treatment significantly reduced PG-APS amounts in livers and spleens compared to controls.
- PG-APS levels in the limbs were comparable between mutanolysin-treated and control rats.
- Mutanolysin extensively degraded PG-APS polymers in all analyzed tissues, reducing their molecular weight.
Conclusions:
- Mutanolysin abrogates PG-APS-induced chronic erosive arthritis in rats.
- The therapeutic effect is attributed to the degradation of PG-APS polymers to a non-arthritogenic size.
- Degradation of PG-APS by mutanolysin is the key mechanism for treating this form of arthritis.