TGF-β latency-associated peptides (LAPs) in human dentin matrix and pulp

Transforming growth factor (TGF)-betas in dentin matrix provide a pool of bioactive molecules, but association with latency-associated peptides (LAPs) may influence their activity. We investigated TGF-beta1, -beta2, and -beta3 LAP expression in sound and carious human teeth. Teeth were fixed and processed immediately following extraction prior to staining with rabbit polyclonal antibodies to the TGF-beta LAPs. A soluble dentin matrix fraction was prepared from dissected human dentin and sequential extraction of pulpal ECM was performed prior to purification. Fractions were Western blotted and probed with the LAP antibodies. All three LAPs were present in odontoblasts, cells of the pulp, and predentin; however, no staining of mineralized dentin matrix was seen. Similar patterns of expression were seen in carious tissue. Expression of TGF-beta LAPs in cells and pulpal matrix of healthy and carious teeth will be important in regulation of TGF-beta activity and may modulate the tissue response to injury.