TCF4 and osteoporosis: Furthermore, S-UNL-E promoted the expression of PTGS2, β-catenin, and TCF4 both in vitro and in vivo, which indicated that S-UNL-E increased the PTGS2 expression thereby promoting the transcription and translation of key gene β-catenin and TCF4 in the Wnt/β-catenin signaling pathway to treat osteoporosis.