title: Confocal microscopy with double immunofluorescence staining reveals the functional transient receptor potential vanilloid subtype 1 expressed in myoepithelial cells of human submandibular glands.
abstract: Myoepithelial cells (MECs) mainly surround acini and intercalated ducts in the human salivary glands. The contraction of MECs provides the expulsive force to promote salivation. We previously found functional transient receptor potential vanilloid subtype 1 (TRPV1) was expressed in rabbit and human submandibular glands and increased saliva secretion. However, it was unknown whether TRPV1 was expressed in MECs of submandibular glands. In this study, we observed the immunoflourescence of TRPV1 was not only located in serous acini and ducts but also surround the basal layer of the acinus and intercalated ducts of human submandibular glands. Double immunofluorescence staining revealed colocalization of TRPV1 with calponin, vimentin, and α-smooth muscle actin, which indicated the myoepithelial expression of TRPV1. Treating submandibular gland tissues with capsaicin, an agonist of TRPV1, substantially increased the phosphorylation of the 20-kDa regulatory light-chain subunit of myosin (MLC(20) ), a crucial molecule for contraction of smooth muscle cells, in MECs. Pretreatment with capsazepine, a specific TRPV1 inhibitor, blocked capsaicin-induced MLC(20) phosphorylation. These results suggest that TRPV1 is expressed in MECs of the human submandibular gland and mediates myoepithelial contraction via a mechanism involving MLC(20) phosphorylation.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Qianwen
authors.initials: Q
authors.lastname: Ding
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: Cong
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Cai
authors.forename: Jingyan
authors.initials: J
authors.lastname: Han
authors.forename: Yunchao
authors.initials: Y
authors.lastname: Su
authors.forename: Li-Ling
authors.initials: LL
authors.lastname: Wu
authors.forename: Guan-Gyan
authors.initials: GG
authors.lastname: Yu
mesh_terms: D000328:Adult; D000368:Aged; D004847:Epithelial Cells / Q000737:chemistry*; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods; D008875:Middle Aged; D032342:Muscle Cells / Q000737:chemistry*; D013194:Staining and Labeling / Q000379:methods; D013363:Submandibular Gland / Q000166:cytology*; D050916:TRPV Cation Channels / Q000032:analysis*
chemical_list: D050916:TRPV Cation Channels; C494482:TRPV1 protein, human