Changes in expression of Hyaluronidase genes during immunization-induced IgE formation.

Hyaluronan (HA) is a glycosaminoglycan that associates with various molecules to assemble a specific HA-rich extracellular matrix. Low and intermediate-molecular-weight HA induces cytokines, chemokines, and other mediators of inflammation and extracellular matrix (ECM) degradation. Hyaluronidases are a group of enzymes that degrade HA. As a model of patients with allergic diseases, we used egg albumin to induce high levels of IgE in rats and examined changes in the expression of hyaluronidase genes (Hyal1 and Hyal2) using reverse transcription-polymerase chain reaction (RT-PCR). The expression of Hyal2 was not affected by the overproduction of IgE induced with egg albumin, whereas the expression of the Hyal1 gene was suppressed. High-molecular-weight HA might be degraded by Hyal2 into intermediate-molecular-weight HA, which can trigger inflammation. [ABSTRACT FROM AUTHOR]