Thymosin Beta-4 Suppresses Osteoclastic Differentiation and Inflammatory Responses in Human Periodontal Ligament Cells

Abstract

BackgroundRecent reports suggest that thymosin beta-4 (Tβ4) is a key regulator for wound healing and anti-inflammation. However, the role of Tβ4 in osteoclast differentiation remains unclear.PurposeThe purpose of this study was to evaluate Tβ4 expression in H2O2-stimulated human periodontal ligament cells (PDLCs), the effects of Tβ4 activation on inflammatory response in PDLCs and osteoclastic differentiation in mouse bone marrow-derived macrophages (BMMs), and identify the underlying mechanism.MethodsReverse transcription-polymerase chain reactions and Western blot analyses were used to measure mRNA and protein levels, respectively. Osteoclastic differentiation was assessed in mouse bone marrow-derived macrophages (BMMs) using conditioned medium (CM) from H2O2-treated PDLCs.ResultsTβ4 was down-regulated in H2O2-exposed PDLCs in dose- and time-dependent manners. Tβ4 activation with a Tβ4 peptide attenuated the H2O2-induced production of NO and PGE2 and up-regulated iNOS, COX-2, and osteoclastogenic cytokines (TNF-α, IL-1β, IL-6, IL-8, and IL-17) as well as reversed the effect on RANKL and OPG in PDLCs. Tβ4 peptide inhibited the effects of H2O2 on the activation of ERK and JNK MAPK, and NF-κB in PDLCs. Furthermore, Tβ4 peptide inhibited osteoclast differentiation, osteoclast-specific gene expression, and p38, ERK, and JNK phosphorylation and NF-κB activation in RANKL-stimulated BMMs. In addition, H2O2 up-regulated Wnt5a and its cell surface receptors, Frizzled and Ror2 in PDLCs. Wnt5a inhibition by Wnt5a siRNA enhanced the effects of Tβ4 on H2O2-mediated induction of pro-inflammatory cytokines and osteoclastogenic cytokines as well as helping osteoclastic differentiation whereas Wnt5a activation by Wnt5a peptide reversed it.ConclusionIn conclusion, this study demonstrated, for the first time, that Tβ4 was down-regulated in ROS-stimulated PDLCs as well as Tβ4 activation exhibited anti-inflammatory effects and anti-osteoclastogenesis in vitro. Thus, Tβ4 activation might be a therapeutic target for inflammatory osteolytic disease, such as periodontitis.

Thymosin beta 10 is a key regulator of tumorigenesis and metastasis and a novel serum marker in breast cancer

“…The beta-thymosin family, primarily including thymosin beta 4 (TMSB4), TMSB10 and TMSB15, function as actin-sequestering proteins to inhibit actin polymerization and disrupt the formation of F-actin [ 5 ]. Furthermore, beta-thymosins exhibit diverse physiological functions beyond actin sequestration, including tissue development and regeneration, anti-inflammatory effects, and induction of insulin secretion [ 6 – 10 ]. Recent studies have focused on the biological roles of beta-thymosins in the progression and metastasis of various types of cancer.…”

Thymosin β4 in rheumatoid arthritis: Friend or foe

“…Notably, a plausible role for Tβ4 in bone degradation by stimulating MMP expression would be inconsistent with a beneficial role in bone metabolism, which Tβ4 has been reported to play (49) by suppressing osteoclastic differentiation in RANKL-stimulated mouse bone-marrow-derived macrophages through the inhibition of osteoclast-specific gene expression, as well as p38, ERK, and JNK phosphorylation and NF-κB activation (50). Furthermore, Tβ4 promotes differentiation and mineralization of MC3T3-E1 cells, which are an osteoblast precursor derived from mouse calvaria (51).…”

Secreted frizzled‐related protein 5 serum levels in human periodontitis—A nested case–control study

“…It was demonstrated that wnt5a mRNA is upregulated in the gingiva of patients with periodontitis (Nanbara et al., ) and a genome‐wide association study found suggestive evidence of association for the wnt5a gene and severe periodontitis (Divaris et al., ). The evolutionary conserved sFRP5 and wnt5a system has increasingly gained attention in the research field of periodontitis over the last years (Divaris et al., ; Hu et al., ; Lee et al., ; Nanbara et al., ; Xu et al., ; Yu et al., ; Zhou, Dorfer, Chen, & Fawzy El‐Sayed, ). Recently, a reciprocal relationship between sFRP5 and wnt5a expression in periodontal health and disease , as well as that sFRP5 could block experimental periodontal inflammation in vivo , was demonstrated (Maekawa et al., ).…”

“…The evolutionary conserved sFRP5 and wnt5a system has increasingly gained attention in the research field of periodontitis over the last years (Divaris et al, 2013;Hu et al, 2016;Lee et al, 2016;Nanbara et al, 2012;Xu et al, 2015;Yu et al, 2015;Zhou, Dorfer, Chen, & Fawzy El-Sayed, 2017). Recently, a reciprocal relationship between sFRP5 and wnt5a expression in periodontal health and disease, as well as that sFRP5 could block experimental periodontal inflammation in vivo, was demonstrated (Maekawa et al, 2017).…”