DMP1 and IFITM5 Regulate Osteogenic Differentiation of MC3T3-E1 on PEO-Treated Ti-6Al-4V-Ca²⁺/P_i surface

Abstract

Despite numerous studies on various surface modifications on titanium and its alloys, it remains unclear what kind of titanium-based surface modifications are capable of controlling cell activity. This study aimed to understand the mechanism at the cellular and molecular levels and investigate the in vitro response of osteoblastic MC3T3-E1 cultured on the Ti-6Al-4V surface modified by plasma electrolytic oxidation (PEO) treatment. A Ti-6Al-4V surface was prepared by PEO at 180, 280, and 380 V for 3 or 10 min in an electrolyte containing Ca 2+ /P i ions. Our results showed that PEO-treated Ti-6Al-4V-Ca 2+ /P i surfaces enhanced the cell attachment and differentiation of MC3T3-E1 compared to the untreated Ti-6Al-4V control but did not affect cytotoxicity as shown by cell proliferation and cell death. Interestingly, on the Ti-6Al-4V-Ca 2+ /P i surface treated by PEO at 280 V for 3 or 10 min, MC3T3-E1 showed a higher initial adhesion and mineralization. In addition, the alkaline phosphatase (ALP) activity significantly increased in MC3T3-E1 on the PEO-treated Ti-6Al-4V-Ca 2+ /P i (280 V for 3 or 10 min). In RNA-seq analysis, the expression of dentin matrix protein 1 (DMP1), sortilin 1 (Sort1), signal-induced proliferation-associated 1 like 2 (SIPA1L2), and interferon-induced transmembrane protein 5 (IFITM5) was induced during the osteogenic differentiation of MC3T3-E1 on the PEO-treated Ti-6Al-4V-Ca 2+ /P i . DMP1 and IFITM5 silencing decreased the expression of bone differentiation-related mRNAs and proteins and ALP activity in MC3T3-E1. These results suggest that the PEO-treated Ti-6Al-4V-Ca 2+ /P i surface induces osteoblast differentiation by regulating the expression of DMP1 and IFITM5. Therefore, surface microstructure modification through PEO coatings with Ca 2+ /P i ions could be used as a valuable method to improve biocompatibility properties of titanium alloys.

ATP-induced cell death: a novel hypothesis for osteoporosis

“…It is widely believed that the dysplasia of osteoblasts and osteoclasts is a factor leading to osteoporosis (Xiao et al, 2023). Estrogen depletion, inflammatory responses, and immune dysregulation [including tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β)] in conjunction with disturbances in calcium ion homeostasis can independently or synergistically trigger apoptotic, autophagic, and necroptotic processes in bone cells, culminating in the onset of osteoporosis (Wang et al, 2023b;Cui et al, 2023;Feng et al, 2023;Jeong et al, 2023;Puts et al, 2023;Xiao et al, 2023;Zhu et al, 2023). Furthermore, aberrant activities of osteoclasts and multinucleated macrophages result in the release of acidifying substances and bone resorption-related proteases, contributing to bone degradation and subsequent osteoporosis (Bao et al, 2023) Importantly, cell death pathways are also implicated in secondary osteoporosis, encompassing conditions such as diabetic osteoporosis, glucocorticoid-induced osteoporosis, and postmenopausal osteoporosis.…”