Promote Mice Txndc5 Mc3t3 E1 Function In Cell Proliferation

Here we investigated the role of Txndc5in cell proliferation in mouse pre-osteoblast cell line MC3T3-E1.Txndc5gene encodes Thioredoxin domain-containing protein5/Endoplasmic reticulum resident protein46(also known as Erp46), which is a member of the endoplasmic reticulum membrane protein thioredoxin family. All members of the family contain a PDI domain, and play important physiological roles, such as cell proliferation, differentiation, angiogenesis, etc. TXNDC5was found to be up-regulated in many cancers, including cervical cancer, uterine cancer, gastric cancer, lung cancer, colorectal cancer, etc. But the role of Txndc5in cell proliferation is poorly understood. There is only one paper reporting that TXNDC5could promote the proliferation of human gastric mucosa cell line HFE-145. Knockdown of TXNDC5reduced the proliferation rate of human MKN-45cell (gastric cancer cell line). So far, there has been no report about the role of Txndc5in osteoblast.By MTS assay and cell cycle distribution analysis, we found that Txndc5was able to enhance MC3T3-E1cell proliferation when over-expressed. Txndc5exerted its effect by up-regulating the expression of Cyclin A and in turn increasing the percentage of cells in S phase. Knockdown of Txndc5down-regulated the expression of Cyclin A, decreased the percentage of cells in S phase, and thus slowed down the cell proliferation. The expression of TxndcS was up-regulated in the accelerated proliferation of MC3T3-E1cells in response to estrogen treatment. Such cell proliferation acceleration by estrogen was blocked by knockdown of Txndc5. This implied that Txndc5might be a new member that involved in the signaling pathways mediating estrogen-induced pre-osteoblast proliferation.