In vivo localization of secretory type V phospholipase A₂ (sPLA₂-V) in human salivary glands under normal and pathological conditions

抄録

Type V secretory phospholipase A₂ (sPLA₂-V) has been implicated in several pathophysiological events including inflammation, eicosanoid production, and antibacterial defense. However, its expression has been recognized in only a few organs such as the heart and lung. This study is the first to demonstrate preferential expression of sPLA₂-V in human salivary glands by immunohistochemistry and in situ hybridization. In normal tissues, sPLA₂-V was expressed in a constitutive manner in serous cells and scarcely in duct epithelia, but not in mucous cells. In contrast in sialoadenitis, sPLA₂-V expression was up-regulated in duct epithelia and some mucous cells, while the tumor cells of pleomorphic adenoma strongly expressed the enzyme. We concluded that sPLA₂-V in salivary glands may play a role for saliva secretions and anti-bacterial defense, in as well as assist in the progression of sialoadenitis and salivary gland tumor formation through prostaglandin production.