Human odontoblasts express transient receptor protein and acid-sensing ion channel mechanosensor proteins

Diverse proteins of the denegerin/epithelial sodium channel (DEG/ENa⁺C) superfamily, in particular those belonging to the acid-sensing ion channel (ASIC) family, as well as some members of the transient receptor protein (TRP) channel, function as mechanosensors or may be required for mechanosensation in a diverse range of species and cell types. Therefore, we investigated the putative mechanosensitive function of human odontoblasts using immunohistochemistry to detect ENa⁺C subunits (α, β, and γ) and ASIC (1, 2, 3, and 4) proteins, as well as TRPV4, in these cells. Positive and specific immunoreactivity in the odontoblast soma and/or processes was detected for all proteins studied except α-ENa⁺C. The intensity of immunostaining was high for β-ENa⁺C and ASIC2, whereas it was low for ASIC1, ASIC3, γ-ENa⁺C, and TRPV4, being absent for α-ENa⁺C and ASIC4. These results suggest that human odontoblasts in situ express proteins related to mechanosensitive channels that probably participate in the mechanisms involved in teeth sensory transmission.