Inflammation and Taste DisordersMechanisms in Taste Buds

摘要

Taste disorders, including taste distortion and taste loss, negatively impact generalhealth and quality of life. To understand the underlying molecular and cellular mech-anisms, we set out to identify inflammation-related molecules in taste tissue and toassess their role in the development of taste dysfunctions. We found that 10 out of 12mammalian Toll-like receptors (TLRs), type I and II interferon (IFN) receptors, and theirdownstream signaling components are present in taste tissue. Some TLRs appear tobe selectively or more abundantly expressed in taste buds than in nongustatory lingualepithelium. Immunohistochemistry with antibodies against TLRs 1,2,3,4,6, and 7 con-firmed the presence of these receptor proteins in taste bud cells, of which TLRs 2,3, and4 are expressed in the gustducin-expressing type II taste bud cells. Administration ofTLR ligands, lipopolysaccharide, and double-stranded RNA polyinosinic:polycytidylicacid, which mimics bacterial or viral infection, activates the IFN signaling pathways,upregulates the expression of IFN-inducible genes, and downregulates the expressionof clos in taste buds. Finally, systemic administration of IFNs augments apoptosis oftaste bud cells in mice. Taken together, these data suggest that TLR and IFN path-ways function collaboratively in recognizing pathogens and mediating inflammatoryresponses in taste tissue. This process, however, may interfere with normal tastetransduction and taste bud cell turnover and contributes to the development of tastedisorders.