RETRACTED: IL-1β-induced, matrix metalloproteinase-3-regulated proliferation of embryonic stem cell-derived odontoblastic cells is mediated by the Wnt5 signaling pathway

The Role of Kallikrein 7 in Tumorigenesis

Kallikrein 7 (KLK7) is a secreted serine protease with chymotrypsic protease activity. Abnormally high expression of KLK7 is closely related to the occurrence and development of various types of cancer. Therefore, KLK7 has been identified as a potential target for cancer drug development design in recent years. KLK7 mediates various biological and pathological processes in tumorigenesis, including cell proliferation, migration, invasion, angiogenesis, and cell metabolism, by hydrolyzing a series of substrates such as membrane proteins, extracellular matrix proteins, and cytokines. This review mainly introduces the downstream cell signaling pathways involved in the activation of KLK7 and its substrate-related proteins. This review will not only help us to better understand the mechanisms of KLK7 in regulating biological and pathological processes of cancer cells, but also lay a solid foundation for the design of inhibitors targeting KLK7.

WNT5B exerts oncogenic effects and is negatively regulated by miR-5587-3p in lung adenocarcinoma progression

WNT5B glycoprotein belongs to the Wnt protein family. Limited investigations revealed a possible role of WNT5B in malignancies, such as triple-negative breast cancer and oral squamous cell carcinoma. However, whether WNT5B contributes to the progression of lung adenocarcinoma (LAD) remains unclear. Here, we initially determine that WNT5B is highly expressed in LAD and is positively correlated with lymph node metastasis and TNM stage. Consistently, clinical analysis reveals WNT5B as an independent prognostic biomarker in LAD. Silencing WNT5B suppresses the proliferation of LAD both in vitro and in vivo by interfering G1/S cell-cycle progression and modulating amino acid metabolism, revealing its remarkable oncogenic role in LAD. Of note, we also identified miR-5587-3p as a negative upstream regulator of WNT5B in LAD, which may help develop therapies targeting LAD patients with high WNT5B expression. Taken together, our results revealed an oncogenic role of WNT5B in LAD, which could be a prognostic biomarker and promising therapeutic target for LAD patients.

Interleukin-1 beta promotes neuronal differentiation through the Wnt5a/RhoA/JNK pathway in cortical neural precursor cells

Pro-inflammatory cytokine interleukin-1 beta (IL-1β) is a key mediator of inflammation and stress in the central nervous system (CNS), and is highly expressed in the developing brain. In this study, we investigated the possible role of IL-1β in neuronal differentiation of cortical neural precursor cells (NPCs). We showed that stimulation with IL-1β increased expression levels of neurotrophin-3 (NT3) and neurogenin 1 (Ngn1) and promoted neurite outgrowth. We also found that IL-1β increased mRNA and protein levels of Wnt5a. Knockdown of Wnt5a by transfection with Wnt5a siRNA inhibited IL-1β-induced neuronal differentiation. Moreover, IL-1β-induced Wnt5a expression was regulated by nuclear factor kappa B (NF-κB) activation, which is involved in IL-1β-mediated neuronal differentiation. To examine the role of Wnt5a in neuronal differentiation of NPCs, we exogenously added Wnt5a. We found that exogenous Wnt5a promotes neuronal differentiation, and activates the RhoA/Rho-associated kinase (ROCK)/c-jun N-terminal kinase (JNK) pathway. In addition, Wnt5a-induced neuronal differentiation was blocked by RhoA siRNA, as well as by a specific Rho-kinase inhibitor (Y27632) or a SAPK/JNK inhibitor (SP600125). Furthermore, treatment with RhoA siRNA, Y27632, or SP600125 suppressed the IL-1β-induced neuronal differentiation. Therefore, these results suggest that the sequential Wnt5a/RhoA/ROCK/JNK pathway is involved in IL-1β-induced neuronal differentiation of NPCs.

Human Dental Pulp Cells Express Cellular Markers for Inflammation and Hard Tissue Formation in Response to Bacterial Information

INTRODUCTION

Lipopolysaccharide (LPS) is a major component of the outer membranes of gram-negative bacteria associated with deep dental caries and pulpitis. When bacteria invade dentinal tubes and dentin is continually destroyed, tertiary dentin is formed by preexisting odontoblasts. However, the relationship between LPS and tertiary dentin formation remains unclear. We investigated whether LPS stimulation induces the formation of hard tissue in human dental pulp cells (hDPCs).

METHODS

Immortalized hDPCs were cultured, and Escherichia coli-derived LPS (1 μg/mL) was incorporated into the culture medium. Samples were obtained after 0, 1, 3, 7, 14, and 21 days, and messenger RNA expression of IL-1β, IL-6, Wnt5a, Runx2, ALP, and alkaline phosphatase (ALP) activity was investigated.

RESULTS

Quantitative real-time polymerase chain reaction revealed higher messenger RNA expression levels of IL-1β and IL-6 in the LPS group on 1 day (P < .05). The expression levels of dentinogenesis-related markers including Wnt5a, Runx2, and ALP were higher in the LPS group (2.0-, 4.7- and 10.0-fold, respectively) than that in the control group at 14 days (P < .01). ALP activity was significantly stronger in the LPS group than in the control group at 21 days (P < .01). Treatment of Box5, an antagonist of Wnt5a, showed a decreased expression of Runx2 and ALP (P < .05).

CONCLUSIONS

These results indicate that LPS stimulation induces the gene expression of inflammatory cytokines and hard tissue formation through Wnt5a signaling pathways in hDPCs.

NLRP4 is an essential negative regulator of fructose-induced cardiac injury in vitro and in vivo

High fructose consumption leads to metabolic syndrome and enhances cardiovascular disease risk. However, our knowledge of the molecular mechanism underlying the cardiac disease caused by fructose feeding is still poor. Nod-like receptors (NLRs) are intracellular sensors, responding to a variety of intracellular danger signals to induce injuries. NLRP4 is a negative regulator of nuclear factor-κB (NF-κB) signaling pathway through interactions with kinase IκB kinase (IKK). Here, we illustrated that NLRP4 attenuates pro-inflammatory cytokines releasing, including Transforming growth factor (TGF-β1), Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-18 (IL-18) and interleukin-6 (IL-6), in fructose-treated cardiac cells by means of RT-qPCR, and western blotting analysis. In addition, NLRP4 could reduce the expression of TANK-binding kinase 1/interferon regulatory factor 3 (TBK1/IRF3), reducing inflammation response and achieving its anti-hypertrophic action. TBK1 plays critical roles in the IRF3 signaling pathway, modulating inflammation response. The inhibition of IKK/NF-κB signaling pathway by NLRP4 is confirmed by NLRP4 over-expression and knockdown. In vivo, high fructose feeding induced cardiac injury, accompanied with reduced expression of NLRP4 in heart tissue samples, indicating the possible role of NLRP4 in ameliorating heart injury. In conclusion, the findings above indicated that NLRP4 is an important mediator of cardiac remodeling in vitro and in vivo through negatively regulating TBK1/IRF3 and IKK/NF-κB signaling pathways, indicating that NLRP4 might be a promising therapeutic target against cardiac inflammation.

Products of dentin matrix protein-1 degradation by interleukin-1β-induced matrix metalloproteinase-3 promote proliferation of odontoblastic cells

We have previously reported that interleukin (IL)-1β induces matrix metalloproteinase (MMP)-3-regulated cell proliferation in mouse embryonic stem cell (ESC)-derived odontoblast-like cells, suggesting that MMP-3 plays a potentially unique physiological role in regeneration by odontoblast-like cells. MMPs are able to process virtually any component of the extracellular matrix, including collagen, laminin and bioactive molecules. Because odontoblasts produce dentin matrix protein-1 (DMP-1), we examined whether the degraded products of DMP-1 by MMP-3 contribute to enhanced proliferation in odontoblast-like cells. IL-1β increased mRNA and protein levels of odontoblastic marker proteins, including DMP-1, but not osteoblastic marker proteins, such as osteocalcin and osteopontin. The recombinant active form of MMP-3 could degrade DMP-1 protein but not osteocalcin and osteopontin in vitro. The exogenous degraded products of DMP-1 by MMP-3 resulted in increased proliferation of odontoblast-like cells in a dose-dependent manner. Treatment with a polyclonal antibody against DMP-1 suppressed IL-1β-induced cell proliferation to a basal level, but identical treatment had no effect on the IL-1β-induced increase in MMP-3 expression and activity. Treatment with siRNA against MMP-3 potently suppressed the IL-1β-induced increase in DMP-1 expression and suppressed cell proliferation (p < 0.05). Similarly, treatment with siRNAs against Wnt5a and Wnt5b suppressed the IL-1β-induced increase in DMP-1 expression and suppressed cell proliferation (p < 0.05). Rat KN-3 cells, representative of authentic odontoblasts, showed similar responses to the odontoblast-like cells. Taken together, our current study demonstrates the sequential involvement of Wnt5, MMP-3, DMP-1 expression, and DMP-1 degradation products by MMP-3, in effecting IL-1β-induced proliferation of ESC-derived odontoblast-like cells.

Polyphosphate-induced matrix metalloproteinase-3-mediated proliferation in rat dental pulp fibroblast-like cells is mediated by a Wnt5 signaling cascade

Although it is known that inorganic polyphosphate [Poly(P)] induces differentiation of osteoblasts, there are few reports concerning its effects on cell proliferation, especially in fibroblasts. Because we found that Poly(P) stimulates the proliferation of purified rat dental pulp fibroblast-like cells (DPFCs), matrix metalloproteinase (MMP)-3 small interfering RNA (siRNA) was transfected into purified rat DPFCs to investigate whether MMP-3 activity is induced by Poly(P) and/or is associated with cell proliferation in DPFCs. Real-time quantitative polymerase chain reaction, Western blots, an MMP-3 activity assay, and an enzyme-linked immunosorbent assay to assess cell proliferation were used in this study. Poly(P) induced expression of MMP-3 mRNA and protein, and increased MMP-3 activity and cell proliferation. Silencing of MMP-3 expression with siRNA yielded potent and significant suppression of Poly(P)-induced MMP-3 expression and activity, and decreased cell proliferation. Poly(P) also increased mRNA and protein levels of Wnt5 and the Wnt receptor Lrp5/Fzd9. Although exogenous MMP-3 could not induce Wnt5, exogenous Wnt5 was found to increase MMP-3 activity and, interestingly, the proliferation rate of DPFCs. Transfection with Wnt5a siRNA suppressed the Poly(P)-induced increase in MMP-3 expression and suppressed cell proliferation. These results demonstrate the sequential involvement of Wnt5 and MMP-3 in Poly(P)-induced proliferation of DPFCs, and may have relevance in our understanding and ability to improve wound healing following dental pulp injury.

Wnt16 Signaling Is Required for IL-1β-Induced Matrix Metalloproteinase-13-Regulated Proliferation of Human Stem Cell-Derived Osteoblastic Cells

We established a differentiation method for homogeneous α7 integrin-positive human skeletal muscle stem cell (α7⁺hSMSC)-derived osteoblast-like (α7⁺hSMSC-OB) cells, and found that interleukin (IL)-1β induces matrix metalloproteinase (MMP)-13-regulated proliferation of these cells. These data suggest that MMP-13 plays a potentially unique physiological role in the regeneration of osteoblast-like cells. Here, we examined whether up-regulation of MMP-13 activity by IL-1β was mediated by Wingless/int1 (Wnt) signaling and increased the proliferation of osteoblast-like cells. IL-1β increased the mRNA and protein levels of Wnt16 and the Wnt receptor Lrp5/Fzd2. Exogenous Wnt16 was found to increase MMP-13 mRNA, protein and activity, and interestingly, the proliferation rate of these cells. Treatment with small interfering RNAs against Wnt16 and Lrp5 suppressed the IL-1β-induced increase in cell proliferation. We revealed that a unique signaling cascade IL-1β→Wnt16→Lrp5→MMP-13, was intimately involved in the proliferation of osteoblast-like cells, and suggest that IL-1β-induced MMP-13 expression and changes in cell proliferation are regulated by Wnt16.

Autophagy-related gene 5 and Wnt5 signaling pathway requires differentiation of embryonic stem cells into odontoblast-like cells

We previously confirmed a unique and unanticipated role for an α2 integrin, extracellular matrix metalloproteinase inducer (Emmprin), and matrix metalloproteinase (MMP)-3-mediated signaling cascade, in driving the odontoblast-like differentiation of mouse embryonic stem (ES) cells in a collagen type-I scaffold (CS) combined with bone morphogenetic protein (BMP)-4 (CS/BMP-4). To explore the early signaling cascade for odontoblastic differentiation, we examined the upregulation of autophagy-related gene (Atg) and Wnt signaling by CS/BMP-4 mediated odontoblast differentiation. In a screening experiment, CS/BMP-4 increased the mRNA and protein levels of Atg5, Lrp5/Fzd9 (an Atg5 receptor), and Wnt5, but not microtubule-associated protein 1 light chain (LC3; a mammalian homolog of yeast Atg8), TFE3, Beclin1, and Atg12, together with the amount of autophagosomes and autophagy fluxes. Treatment with siRNAs against Atg5 and Wnt5 individually suppressed the CS/BMP-4-induced increase in odontoblast differentiation. The odontoblastic phenotype, involving dentin matrix protein-1 and dentin sialophosphoprotein expression, decreased when autophagy was inhibited by chloroquine, but increased after treatment with rapamycin (an autophagy enhancer). Taken together with our previous findings, we have revealed a unique sequential cascade involving Atg5, Wnt5a, α2 integrin, Emmprin, and MMP-3. This cascade results in a potent increase in odontoblastic cell differentiation, indicating the unique involvement of Atg5, autophagy and Wnt5 signaling in CS/BMP-4-induced differentiation of ES cells into odontoblast-like cells, at a relatively early stage.

Interleukin-1β-induced autophagy-related gene 5 regulates proliferation of embryonic stem cell-derived odontoblastic cells

We previously established a method for the differentiation of induced pluripotent stem cells and embryonic stem cells into α2 integrin-positive odontoblast-like cells. We also reported that Wnt5 in response to interleukin (IL)-1β induces matrix metalloproteinase (MMP)-3-regulated cell proliferation in these cells. Our findings suggest that MMP-3 plays a potentially unique physiological role in the generation of odontoblast-like cells under an inflammatory state. Here, we examined whether up-regulation of autophagy-related gene (Atg) 5 by IL-1β was mediated by Wnt5 signaling, thus leading to increased proliferation of odontoblast-like cells. IL-1β increased the mRNA and protein levels of Atg5, microtubule-associated protein 1 light chain (LC3, a mammalian homolog of yeast Atg8) and Atg12. Treatment with siRNAs against Atg5, but not LC3 and Atg12, suppressed the IL-1β-induced increase in MMP-3 expression and cell proliferation. Our siRNA analyses combined with western blot analysis revealed a unique sequential cascade involving Atg5, Wnt5a and MMP-3, which resulted in the potent increase in odontoblastic cell proliferation. These results demonstrate the unique involvement of Atg5 in IL-1β-induced proliferation of embryonic stem cell-derived odontoblast-like cells.

Polyphosphate induces matrix metalloproteinase-3-mediated proliferation of odontoblast-like cells derived from induced pluripotent stem cells

Inorganic polyphosphate [Poly(P)] may represent a physiological source of phosphate and has the ability to induce bone differentiation in osteoblasts. We previously reported that cytokine-induced matrix metalloproteinase (MMP)-3 accelerates the proliferation of purified odontoblast-like cells. In this study, MMP-3 small interfering RNA (siRNA) was transfected into odontoblast-like cells derived from induced pluripotent stem cells to investigate whether MMP-3 activity is induced by Poly(P) and/or is associated with cell proliferation and differentiation into odontoblast-like cells. Treatment with Poly(P) led to an increase in both cell proliferation and additional odontoblastic differentiation. Poly(P)-treated cells showed a small but significant increase in dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP-1) mRNA expression, which are markers of mature odontoblasts. The cells also acquired additional odontoblast-specific properties including adoption of an odontoblastic phenotype typified by high alkaline phosphatase (ALP) activity and a calcification capacity. In addition, Poly(P) induced expression of MMP-3 mRNA and protein, and increased MMP-3 activity. MMP-3 siRNA-mediated disruption of the expression of these effectors potently suppressed the expression of odontoblastic biomarkers ALP, DSPP, and DMP-1, and blocked calcification. Interestingly, upon siRNA-mediated silencing of MMP-3, we noted a potent and significant decrease in cell proliferation. Using specific siRNAs, we revealed that a unique signaling cascade, Poly(P)→MMP-3→DSPP and/or DMP-1, was intimately involved in the proliferation of odontoblast-like cells.