Wnt5a activates THP-1 monocytic cells via a β-catenin-independent pathway involving JNK and NF-κB activation

Wnt5a: A promising therapeutic target for inflammation, especially rheumatoid arthritis

BACKGROUND

Wnt5a is a member of the Wnt protein family, which acts on classical or multiple non-classical Wnt signaling pathways by binding to different receptors. The expression regulation and signal transduction of Wnt5a is closely related to the inflammatory response. Abnormal activation of Wnt5a signaling is an important part of inflammation and rheumatoid arthritis (RA).

OBJECTIVES

This paper mainly focuses on Wnt5a protein and its mediated signaling pathway, summarizes the latest research progress of Wnt5a in the pathological process of inflammation and RA, and looks forward to the main directions of Wnt5a in RA research, aiming to provide a theoretical basis for the prevention and treatment of RA diseases by targeting Wnt5a.

RESULTS

Wnt5a is highly expressed in activated blood vessels, histocytes and synoviocytes in inflammatory diseases such as sepsis, sepsis, atherosclerosis and rheumatoid arthritis. It mediates the production of pro-inflammatory cytokines and chemokines, regulates the migration and recruitment of various immune effector cells, and thus participates in the inflammatory response. Wnt5a plays a pathological role in synovial inflammation and bone destruction of RA, and may be an important clinical therapeutic target for RA.

CONCLUSION

Wnt5a is involved in the pathological process of inflammation and interacts with inflammatory factors. Wnt5a may be a new target for regulating the progression of RA disease and intervening therapy because of its multi-modal effects on the etiology of RA, especially as a regulator of osteoclast activity and inflammation.

The molecular mechanisms of remodeling in asthma, COPD and IPF with a special emphasis on the complex role of Wnt5A

INTRODUCTION

Chronic inflammatory lung diseases are a common cause of suffering and death. Chronic obstructive pulmonary disease (COPD) is the reason for 6% of all deaths worldwide. A total of 262 million people are affected by asthma and 461,000 people died in 2019. Idiopathic pulmonary fibrosis (IPF) is diagnosed in 3 million people worldwide, with an onset over the age of 50 with a mean survival of only 24-30 months. These three diseases have in common that remodeling of the lung tissue takes place, which is responsible for an irreversible decline of lung function. Pathological lung remodeling is mediated by a complex interaction of different, often misguided, repair processes regulated by a variety of mediators. One group of these, as has recently become known, are the Wnt ligands. In addition to their well-characterized role in embryogenesis, this group of glycoproteins is also involved in immunological and structural repair processes. Depending on the combination of the Wnt ligand with its receptors and co-receptors, canonical and noncanonical signaling cascades can be induced. Wnt5A is a mediator that is described mainly in noncanonical Wnt signaling and has been shown to play an important role in different inflammatory diseases and malignancies.

OBJECTIVES

In this review, we summarize the literature available regarding the role of Wnt5A as an immune modulator and its role in the development of asthma, COPD and IPF. We will focus specifically on what is known about Wnt5A concerning its role in the remodeling processes involved in the chronification of the diseases.

CONCLUSION

Wnt5A has been shown to be involved in all three inflammatory lung diseases. Since the ligand affects both structural and immunological processes, it is an interesting target for the treatment of lung diseases whose pathology involves a restructuring of the lung tissue triggered in part by an inflammatory immune response.

Wnt Signaling in the Phenotype and Function of Tumor-Associated Macrophages

Tumor-associated macrophages (TAM) play an important role in supporting tumor growth and suppressing antitumor immune responses, and TAM infiltration has been associated with poor patient prognosis in various cancers. TAMs can be classified as pro-inflammatory, M1-like, or anti-inflammatory, M2-like. While multiple factors within the tumor microenvironment affect the recruitment, polarization, and functions of TAMs, accumulating evidence suggests that Wnt signaling represents an important, targetable driver of an immunosuppressive, M2-like TAM phenotype. TAM production of Wnt ligands mediates TAM-tumor cross-talk to support cancer cell proliferation, invasion, and metastasis. Targeting TAM polarization and the protumorigenic functions of TAMs through inhibitors of Wnt signaling may prove a beneficial treatment strategy in cancers where macrophages are prevalent in the microenvironment.

SFRP5 Enhances Wnt5a Induced-Inflammation in Rheumatoid Arthritis Fibroblast-Like Synoviocytes

Background

Tissue derived fibroblast-like synoviocytes (td-FLS) are key actors in pannus formation and contribute to joint destruction and inflammation during rheumatoid arthritis (RA). Several members of the Wnt family, including Wnt5a, may contribute to RA td-FLS activation and can potentially serve as therapeutic targets.

Objective

The present work aimed to investigate the expression of Wnt5a signaling elements in RA td-FLS and their potential precursors (fluid derived (fd) FLS and fibrocytes). We also studied the role of Wnt5a in RA td-FLS pro-inflammatory activity and whether the inhibitor SFRP5 could restore Wnt5a-induced synovial dysfunction in vitro.

Materials and Methods

The levels of Wnt5a, SFRP5, Wnt5a receptors/coreceptors and Wnt5a pro-inflammatory targets were determined in cultured RA td-FLS, fd-FLS and fibrocytes using qPCR under basal conditions. The expression of pro-inflammatory molecules was assessed after RA td-FLS stimulation with Wnt5a and SFRP5 at different time points.

Results

Our data showed that td-FLS, fd-FLS and fibrocytes from patients with RA expressed similar levels of Wnt5a and a set of Wnt5a receptors/coreceptors. We also demonstrated that Wnt5a stimulated the expression of the pro-inflammatory targets, especially IL1β, IL8 and IL6 in RA td-FLS. Wnt5a-induced inflammation was enhanced in the presence of SFRP5. Furthermore, Wnt5a alone and in conjunction with SFRP5 inhibited the gene expression of TCF4 and the protein levels of the canonical coreceptor LRP5.

Conclusion

Wnt5a pro-inflammatory effect is not inhibited but enhanced by SFRP5 in RA td-FLS. This research highlights the importance of carefully evaluating changes in Wnt5a response in the presence of SFRP5.

The emerging role of Wnt5a in the promotion of a pro-inflammatory and immunosuppressive tumor microenvironment

Wnt5a is the prototypical activator of the non-canonical Wnt pathways, and its overexpression has been implicated in the progression of several tumor types by promoting cell motility, invasion, EMT, and metastasis. Recent evidences have revealed a novel role of Wnt5a in the phosphorylation of the NF-κB subunit p65 and the activation of the NF-κB pathway in cancer cells. In this article, we review the molecular mechanisms and mediators defining a Wnt5a/NF-κB signaling pathway and propose that the aberrant expression of Wnt5a in some tumors drives a Wnt5a/NF-κB/IL-6/STAT3 positive feedback loop that amplifies the effects of Wnt5a. The evidences discussed here suggest that Wnt5a has a double effect on the tumor microenvironment. First, it activates an autocrine ROR1/Akt/p65 pathway that promotes inflammation and chemotaxis of immune cells. Then, Wnt5a activates a TLR/MyD88/p50 pathway exclusively in myelomonocytic cells promoting the synthesis of the anti-inflammatory cytokine IL-10 and a tolerogenic phenotype. As a result of these mechanisms, Wnt5a plays a negative role on immune cell function that contributes to an immunosuppressive tumor microenvironment and would contribute to resistance to immunotherapy. Finally, we summarized the development of different strategies targeting either Wnt5a or the Wnt5a receptor ROR1 that can be helpful for cancer therapy by contributing to generate a more immunostimulatory tumor microenvironment.

Oxidized Low-Density Lipoprotein Induces WNT5A Signaling Activation in THP-1 Derived Macrophages and a Human Aortic Vascular Smooth Muscle Cell Line

The pathogenesis of atherosclerosis is complex, evolves, and involves many cell types. Macrophages and vascular smooth muscle cells (VSMCs) are critically involved in atherosclerosis development and progression. Several studies have shown that WNT5A protein is abundantly expressed in human atherosclerotic lesions; however, the mechanism and role of WNT signaling pathway activation is not clearly known. Using THP-1 derived macrophages, and human aortic VSMC cells, we evaluated in vitro how oxidized low-density lipoprotein (oxLDL) and WNT5A signaling interact in these two cell lines. We used western blot, scratch assay, metabolic proliferation assay, as well as immunostaining to analyze the effect of Wnt signaling activation. The results demonstrated that oxLDL, as well as WNT5A (control), induced Disheveled-2 (DVL2) activation and Kif26b degradation, indicating activation of non-canonical Wnt signaling. We found that oxLDL and WNT5A induced FZD5-ROR2 co-localization at the cellular membrane in vitro in THP-1 derived macrophages. Box5 (FZD5 receptor antagonist) inhibited oxLDL-induced DVL2/JNK activation secondary to newly secreted WNT protein from THP-1 derived macrophages. We found that WNT3A (canonical Wnt) and WNT5A showed different roles in this VSMC cell line. These findings indicate that WNT5A is upregulated by oxLDL, promotes foam cell formation, and affects VSMC phenotype and migration in these two cell lines. Also, in these cell lines FZD5 signaling seems to be necessary for lipid accumulation and, through this mechanism, WNT5A could modulate foam cell formation. Thus, our results suggest that WNT5A may contribute to the pathogenesis of vascular disease through modulating macrophage and VSMC behavior.

An Autocrine Wnt5a Loop Promotes NF-κB Pathway Activation and Cytokine/Chemokine Secretion in Melanoma

Wnt5a signaling has been implicated in the progression of cancer by regulating multiple cellular processes, largely migration and invasion, epithelial-mesenchymal transition (EMT), and metastasis. Since Wnt5a signaling has also been involved in inflammatory processes in infectious and inflammatory diseases, we addressed the role of Wnt5a in regulating NF-κB, a pivotal mediator of inflammatory responses, in the context of cancer. The treatment of melanoma cells with Wnt5a induced phosphorylation of the NF-κB subunit p65 as well as IKK phosphorylation and IκB degradation. By using cDNA overexpression, RNA interference, and dominant negative mutants we determined that ROR1, Dvl2, and Akt (from the Wnt5a pathway) and TRAF2 and RIP (from the NF-κB pathway) are required for the Wnt5a/NF-κB crosstalk. Wnt5a also induced p65 nuclear translocation and increased NF-κB activity as evidenced by reporter assays and a NF-κB-specific upregulation of RelB, Bcl-2, and Cyclin D1. Further, stimulation of melanoma cells with Wnt5a increased the secretion of cytokines and chemokines, including IL-6, IL-8, IL-11, and IL-6 soluble receptor, MCP-1, and TNF soluble receptor I. The inhibition of endogenous Wnt5a demonstrated that an autocrine Wnt5a loop is a major regulator of the NF-κB pathway in melanoma. Taken together, these results indicate that Wnt5a activates the NF-κB pathway and has an immunomodulatory effect on melanoma through the secretion of cytokines and chemokines.

Notum attenuates HBV-related liver fibrosis through inhibiting Wnt 5a mediated non-canonical pathways

Background

Non-canonical Wnt pathways play important roles in liver fibrosis. Notum is a newly discovered inhibitor to Wnt proteins. This study was to investigate anti-fibrotic effects of Notum.

Methods

53 patients with hepatitis B virus (HBV) infection as well as a cell co-culture system of LX-2 and Hep AD38 cells were engaged in this study. Clinical, biological and virological data of each patient were analyzed. Cell viability was detected at different time points. mRNA and protein levels of NFATc1 (Nuclear factor of activated T-cells), Jnk, α-SMA, Col1A1 and TIMP-1 were detected both in LX-2 and liver tissue. Protein levels of NFATc1 and Jnk in liver tissue and their correlations with fibrosis score were analyzed.

Results

Hepatitis B virus replication up-regulated Wnt5a induced NFATc1 and Jnk activity in Hep AD38. Notum suppressed NFATc1, Jnk and fibrosis genes expression, reduced cell viability in co-cultured LX-2 cells induced by HBV. Interestingly, Patients with HBV DNA > 5log copies/ml had higher mRNA levels of NFATc1 and fibrosis genes than patients with HBV DNA < 5log copies/ml. Most importantly, protein expressions of NFATc1 and pJnk have positive correlations with liver fibrosis scores in HBV-infected patients.

Conclusions

Our data showed that Notum inhibited HBV-induced liver fibrosis through down-regulating Wnt 5a mediated non-canonical pathways. This study shed light on anti-fibrotic treatment.

Evaluation of STAT1 and Wnt5a gene expression in gingival tissues of patients with periodontal disease

Periodontal disease is a common chronic inflammatory disease of the oral cavity. This disease occurs as a consequence of uncontrolled inflammatory immune responses against periodontopathic bacteria. Several studies have documented the proinflammatory roles of the Signal Transducer and Activator of Transcription 1 (STAT1) and Wnt5a in inflammatory diseases. However, there has been no detailed investigation of STAT1 and Wnt5a genes expression in periodontal disease. So, we aimed to evaluate the expressions of STAT1 and Wnt5a in patients with chronic and aggressive periodontitis and determine their correlation with clinical parameters. Three groups of subjects were enrolled including control (20 healthy individuals), chronic (25 patients), and aggressive periodontitis patients (25 patients). The expressions of STAT1 and Wnt5a were evaluated in gingival tissue samples using a Real-time polymerase chain reactions assay. The expressions of STAT1 and Wnt5a were significantly upregulated in chronic and aggressive periodontitis compared with the healthy control. We also found that the expressions of STAT1 and Wnt5a increased in aggressive periodontitis compared with chronic periodontitis. In addition, there was the linear relationship between the expression of STAT1 and Wnt5a and the clinical parameters, including clinical attachment loss and periodontal pocket depth. A linear relationship between the expressions of Wnt5a and the clinical parameters was also identified. Taken together, our findings highlight the roles of STAT1 and Wnt5a in the pathogenesis of the periodontal inflammation, suggesting these molecules as valuable therapeutic targets.

Non‑canonical Wnt signaling contributes to ventilator‑induced lung injury through upregulation of WISP1 expression

Mechanical ventilation may cause ventilator-induced lung injury (VILI). Canonical Wnt signaling has been reported to serve an important role in the pathogenesis of VILI. Bioinformatics analysis revealed that canonical and non-canonical Wnt signaling pathways were activated in VILI. However, the role of non-canonical Wnt signaling in the pathogenesis of VILI remains unclear. The present study aimed to analyze the potential role of non-canonical Wnt signaling in VILI pathogenesis. Lung injury was assessed via Evans blue albumin permeability and histological scoring, as well as by inflammatory cytokine expression and total protein concentration in bronchoalveolar lavage fluid. The relative protein expression of canonical and non-canonical Wnt signaling pathway components were examined via western blotting and immunohistochemistry. The results demonstrated that 6 h of mechanical ventilation at low tidal volume (LTV; 6 ml/kg) or moderate tidal volume (MTV; 12 ml/kg) induced lung injury in sensitive A/J mice. Ventilation with MTV increased the protein levels of Wnt-induced secreted protein 1 (WISP1), Rho-associated protein kinase 1 (ROCK1), phosphorylated (p)-Ras homolog gene family, member A and p-C-Jun N-terminal kinase (JNK). Inhibition of ROCK1 by Y27632 and JNK by SP600125 attenuated MTV-induced lung injury and decreased the expression of proteins involved in non-canonical Wnt signaling, including WISP1. In conclusion, non-canonical Wnt signaling participates in VILI by modulating WISP1 expression, which has been previously noted as critical for VILI development. Therefore, the non-canonical Wnt signaling pathway may provide a preventive and therapeutic target in VILI.

The cardiac microenvironment uses non-canonical WNT signaling to activate monocytes after myocardial infarction

A disturbed inflammatory response following myocardial infarction (MI) is associated with poor prognosis and increased tissue damage. Monocytes are key players in healing after MI, but little is known about the role of the cardiac niche in monocyte activation. This study investigated microenvironment‐dependent changes in inflammatory monocytes after MI. RNA sequencing analysis of murine Ly6C^high monocytes on day 3 after MI revealed differential regulation depending on location. Notably, the local environment strongly impacted components of the WNT signaling cascade. Analysis of WNT modulators revealed a strong upregulation of WNT Inhibitory Factor 1 (WIF1) in cardiomyocytes—but not fibroblasts or endothelial cells—upon hypoxia. Compared to wild‐type (WT) littermates, WIF1 knockout mice showed severe adverse remodeling marked by increased scar size and reduced ejection fraction 4 weeks after MI. While FACS analysis on day 1 after MI revealed no differences in neutrophil numbers, the hearts of WIF1 knockouts contained significantly more inflammatory monocytes than hearts from WT animals. Next, we induced AAV‐mediated cardiomyocyte‐specific WIF1 overexpression, which attenuated the monocyte response and improved cardiac function after MI, as compared to control‐AAV‐treated animals. Finally, WIF1 overexpression in isolated cardiomyocytes limited the activation of non‐canonical WNT signaling and led to reduced IL‐1β and IL‐6 expression in monocytes/macrophages. Taken together, we investigated the cardiac microenvironment's interaction with recruited monocytes after MI and identified a novel mechanism of monocyte activation. The local initiation of non‐canonical WNT signaling shifts the accumulating myeloid cells toward a pro‐inflammatory state and impacts healing after myocardial infarction.

Biological functions of macrophage-derived Wnt5a, and its roles in human diseases

Wnt5a is implicated in development and tissue homeostasis by activating β-catenin-independent pathway. Excessive production of Wnt5a is related to some human diseases. Macrophage recruitment is a character of inflammation and cancer, therefore macrophage-derived Wnt5a is supposed to be a player in these conditions. Actually, macrophage-derived Wnt5a maintains macrophage immune function, stimulates pro-inflammatory cytokine release, and induces angiogenesis and lymphangiogenesis. Furthermore, macrophage-derived Wnt5a is involved in insulin resistance, atherosclerosis and cancer. These findings indicate that macrophage-derived Wnt5a may be a target in the treatment of these diseases. Notably, unlike macrophages, the exact role of macrophage-derived Wnt5a in bacterial infection remains largely unknown.

The Cks1/Cks2 axis fine-tunes Mll1 expression and is crucial for MLL-rearranged leukaemia cell viability

The Cdc28 protein kinase subunits, Cks1 and Cks2, play dual roles in Cdk-substrate specificity and Cdk-independent protein degradation, in concert with the E3 ubiquitin ligase complexes SCFSkp2 and APCCdc20. Notable targets controlled by Cks include p27 and Cyclin A. Here, we demonstrate that Cks1 and Cks2 proteins interact with both the MllN and MllC subunits of Mll1 (Mixed-lineage leukaemia 1), and together, the Cks proteins define Mll1 levels throughout the cell cycle. Overexpression of CKS1B and CKS2 is observed in multiple human cancers, including various MLL-rearranged (MLLr) AML subtypes. To explore the importance of MLL-Fusion Protein regulation by CKS1/2, we used small molecule inhibitors (MLN4924 and C1) to modulate their protein degradation functions. These inhibitors specifically reduced the proliferation of MLLr cell lines compared to primary controls. Altogether, this study uncovers a novel regulatory pathway for MLL1, which may open a new therapeutic approach to MLLr leukaemia.

Differential effects of Wnt5a on the proliferation, differentiation and inflammatory response of keratinocytes

The predominant role of Wnt family member 5A (Wnt5a) is to induce non-canonical Wnt signalling pathways, including the Wnt‑Ca2+ and Wnt‑planar cell polarity pathways. Enhanced Wnt5a expression is involved in the formation of psoriatic plaques; however, its mechanistic role remains to be determined. In the present study, the effects of Wnt5a expression on HaCaT keratinocytes were investigated. HaCaT cells were cultured in medium supplemented with 0, 40 or 80 ng/ml Wnt5a for 24 h. Cell proliferation, the cell cycle, gene expression and inflammatory responses were investigated using Cell‑Counting Kit‑8 assays, flow cytometry analyses, reverse transcription‑quantitative polymerase chain reaction analyses and enzyme‑linked immunosorbent assays, respectively. Wnt5a treatment was revealed to suppress cell proliferation in HaCaT cells. Furthermore, Wnt5a was also demonstrated to increase the proportion of HaCaT cells arrested at the G2/M phase of the cell cycle, but reduce the proportion of HaCaT cells arrested at G0/G1 phase cells. In addition, the expression levels of the differentiation markers, including filaggrin, keratin 1 and keratin 10 were revealed to be downregulated in HaCaT cells. Expression of the canonical Wnt signalling genes (β‑catenin and cyclin D1) and proliferation markers, such as Ki‑67 and proliferating cell nuclear antigen in HaCaT cells were also revealed to be downregulated. However, the expression levels of inflammatory response markers (interferon‑γ, interleukin‑8 and interleukin‑17A) were revealed to be upregulated in HaCaT cells following Wnt5a treatment. These findings suggest that Wnt5a expression may be involved in the inhibition of cell differentiation and the induction of an inflammatory response in patients with psoriasis.

The Wnt Blows: On the Functional Role of Wnt Signaling in Mycobacterium tuberculosis Infection and Beyond

In recent years, it has become apparent that the Wnt signaling pathway, known for its essential functions in embryonic development and tissue homeostasis, exerts immunomodulatory functions during inflammation and infection. Most functional studies indicate that Wnt5a exerts pro-inflammatory functions on its cellular targets, which include various types of immune and non-immune cells. Wnt5a expression has also been linked to the pathogenesis of chronic inflammatory diseases. Activation of beta-catenin-dependent Wnt signaling, e.g., by Wnt3a, has however been shown to limit inflammation by interfering with the nuclear factor kappa-light chain-enhancer of activated B-cells (NF-kappaB) pathway. This review focuses on the regulation of Wnt5a, Wnt3a, and the recently identified Wnt6 and their functional role in bacterial infections with a primary focus on pulmonary tuberculosis, a leading infectious cause of morbidity and mortality worldwide.

CRC-113 gene expression signature for predicting prognosis in patients with colorectal cancer

Colorectal cancer (CRC) is the third leading cause of global cancer mortality. Recent studies have proposed several gene signatures to predict CRC prognosis, but none of those have proven reliable for predicting prognosis in clinical practice yet due to poor reproducibility and molecular heterogeneity. Here, we have established a prognostic signature of 113 probe sets (CRC-113) that include potential biomarkers and reflect the biological and clinical characteristics. Robustness and accuracy were significantly validated in external data sets from 19 centers in five countries. In multivariate analysis, CRC-113 gene signature showed a stronger prognostic value for survival and disease recurrence in CRC patients than current clinicopathological risk factors and molecular alterations. We also demonstrated that the CRC-113 gene signature reflected both genetic and epigenetic molecular heterogeneity in CRC patients. Furthermore, incorporation of the CRC-113 gene signature into a clinical context and molecular markers further refined the selection of the CRC patients who might benefit from postoperative chemotherapy. Conclusively, CRC-113 gene signature provides new possibilities for improving prognostic models and personalized therapeutic strategies.

WNT5A-ROR2 is induced by inflammatory mediators and is involved in the migration of human ovarian cancer cell line SKOV-3

Background

Wnt5A, which is a member of the non-transforming Wnt protein family, is implicated in inflammatory processes. It is also highly expressed by ovarian cancer cells. ROR2, which is a member of the Ror-family of receptor tyrosine kinases, acts as a receptor or co-receptor for Wnt5A. The Wnt5A–ROR2 signaling pathway plays essential roles in the migration and invasion of several types of tumor cell and influences their cell polarity. We investigated the modulation of Wnt5A–ROR2 by inflammatory mediators and its involvement in the migration of the human ovarian cancer cell line SKOV-3.

Methods

SKOV-3 cells were treated with LPS (lipopolysaccharide), LTA (lipoteichoic acid) and recombinant human IL-6 alone or in combination with STAT3 inhibitor (S1155S31-201) or NF-kB inhibitor (BAY11-7082) for 4, 8, 12, 24 and 48 h. The Wnt5A and ROR2 expression levels were determined at the gene and protein levels. Cells were transfected with specific siRNA against Wnt5A in the absence or presence of human anti-ROR2 antibody and cell migration was assessed using transwells.

Results

There was a strong downregulation of Wnt5A expression in the presence of STAT3 or NF-kB inhibitors. Cell stimulation with LTA or IL-6 for 8 h led to significantly increased levels of Wnt5A (5- and 3-fold higher, respectively). LPS, LTA or IL-6 treatment significantly increased ROR2 expression (2-fold after 48 h). LPS- or LTA-induced Wnt5A or ROR2 expression was abrogated in the presence of STAT3 inhibitor (p < 0.001). IL-6-induced Wnt5A expression was abrogated by both STAT3 and NF-kB inhibitors (p < 0.001). Although not significant, IL-6-induced ROR2 expression showed a modest decrease when STAT3 inhibitor was used. Moreover, cell migration was decreased by 80 % in siRNA Wnt5A-transfected cells in the presence of anti-human ROR2 antibody (p < 0.001).

Conclusions

This study revealed for the first time that inflammatory mediators modulate Wnt5A and ROR2 through NF-kB and STAT3 transcription factors and this may play a role in ovarian cancer cell migration. The results described here provide new insight into the role of the Wnt5A–ROR2 complex in ovarian cancer progression in relation to inflammation.

Ehrlichia chaffeensis Exploits Canonical and Noncanonical Host Wnt Signaling Pathways To Stimulate Phagocytosis and Promote Intracellular Survival

Ehrlichia chaffeensis invades and survives in phagocytes by modulating host cell processes and evading innate defenses, but the mechanisms are not fully defined. Recently we have determined that E. chaffeensis tandem repeat proteins (TRPs) are type 1 secreted effectors involved in functionally diverse interactions with host targets, including components of the evolutionarily conserved Wnt signaling pathways. In this study, we demonstrated that induction of host canonical and noncanonical Wnt pathways by E. chaffeensis TRP effectors stimulates phagocytosis and promotes intracellular survival. After E. chaffeensis infection, canonical and noncanonical Wnt signalings were significantly stimulated during early stages of infection (1 to 3 h) which coincided with dephosphorylation and nuclear translocation of β-catenin, a major canonical Wnt signal transducer, and NFATC1, a noncanonical Wnt transcription factor. In total, the expression of ∼44% of Wnt signaling target genes was altered during infection. Knockdown of TRP120-interacting Wnt pathway components/regulators and other critical components, such as Wnt5a ligand, Frizzled 5 receptor, β-catenin, nuclear factor of activated T cells (NFAT), and major signaling molecules, resulted in significant reductions in the ehrlichial load. Moreover, small-molecule inhibitors specific for components of canonical and noncanonical (Ca(2+) and planar cell polarity [PCP]) Wnt pathways, including IWP-2, which blocks Wnt secretion, significantly decreased ehrlichial infection. TRPs directly activated Wnt signaling, as TRP-coated microspheres triggered phagocytosis which was blocked by Wnt pathway inhibitors, demonstrating a key role of TRP activation of Wnt pathways to induce ehrlichial phagocytosis. These novel findings reveal that E. chaffeensis exploits canonical and noncanonical Wnt pathways through TRP effectors to facilitate host cell entry and promote intracellular survival.

Secreted Frizzled-related Protein 5 Diminishes Cardiac Inflammation and Protects the Heart from Ischemia/Reperfusion Injury

Wnt signaling has diverse actions in cardiovascular development and disease processes. Secreted frizzled-related protein 5 (Sfrp5) has been shown to function as an extracellular inhibitor of non-canonical Wnt signaling that is expressed at relatively high levels in white adipose tissue. The aim of this study was to investigate the role of Sfrp5 in the heart under ischemic stress. Sfrp5 KO and WT mice were subjected to ischemia/reperfusion (I/R). Although Sfrp5-KO mice exhibited no detectable phenotype when compared with WT control at baseline, they displayed larger infarct sizes, enhanced cardiac myocyte apoptosis, and diminished cardiac function following I/R. The ischemic lesions of Sfrp5-KO mice had greater infiltration of Wnt5a-positive macrophages and greater inflammatory cytokine and chemokine gene expression when compared with WT mice. In bone marrow-derived macrophages, Wnt5a promoted JNK activation and increased inflammatory gene expression, whereas treatment with Sfrp5 blocked these effects. These results indicate that Sfrp5 functions to antagonize inflammatory responses after I/R in the heart, possibly through a mechanism involving non-canonical Wnt5a/JNK signaling.

Exome sequencing of a colorectal cancer family reveals shared mutation pattern and predisposition circuitry along tumor pathways

The molecular basis of cancer and cancer multiple phenotypes are not yet fully understood. Next Generation Sequencing promises new insight into the role of genetic interactions in shaping the complexity of cancer. Aiming to outline the differences in mutation patterns between familial colorectal cancer cases and controls we analyzed whole exomes of cancer tissues and control samples from an extended colorectal cancer pedigree, providing one of the first data sets of exome sequencing of cancer in an African population against a background of large effective size typically with excess of variants. Tumors showed hMSH2 loss of function SNV consistent with Lynch syndrome. Sets of genes harboring insertions-deletions in tumor tissues revealed, however, significant GO enrichment, a feature that was not seen in control samples, suggesting that ordered insertions-deletions are central to tumorigenesis in this type of cancer. Network analysis identified multiple hub genes of centrality. ELAVL1/HuR showed remarkable centrality, interacting specially with genes harboring non-synonymous SNVs thus reinforcing the proposition of targeted mutagenesis in cancer pathways. A likely explanation to such mutation pattern is DNA/RNA editing, suggested here by nucleotide transition-to-transversion ratio that significantly departed from expected values (p-value 5e-6). NFKB1 also showed significant centrality along with ELAVL1, raising the suspicion of viral etiology given the known interaction between oncogenic viruses and these proteins.

Secreted frizzled-related protein 5 (Sfrp5) decreases hepatic stellate cell activation and liver fibrosis

BACKGROUND & AIMS

Obesity-related adipocytokine dysregulation is known to accelerate liver fibrosis progression. Recently, a natural Wnt5a inhibitor, secreted frizzled-related protein 5 (Sfrp5), was identified as a novel adipocytokine that has reduced expression in obese adipose tissue in both rodents and human. In addition, hepatic gene expression of Wnt5a and its receptor frizzled 2 (Fz2) is elevated during fibrosis progression. Therefore, Sfrp5 could have biological significance in liver fibrosis.

METHODS

We first investigated the effects of Sfrp5 on primary cultured mouse hepatic stellate cells (HSCs) in vitro. Next, to elucidate the roles of Sfrp5 in liver fibrosis, we investigated a carbon-tetrachloride (CCl4 )-induced liver fibrosis model using Sfrp5 knockout (KO) and wild type (WT) mice in vivo. Each mouse was injected intraperitoneally with CCl4 (0.5 ml/kg) or olive oil as a single dose (acute liver injury model), or twice a week for 6 weeks (liver fibrosis model).

RESULTS

In in vitro studies, Wnt5a enhanced both proliferation and migration of HSCs, and these effects could be completely blocked by Sfrp5. Moreover, siRNA knockdown of Fz2 in HSCs could block the effects of Wnt5a on both HSC proliferation and migration. In in vivo studies, there were no differences in the CCl4 -induced liver injury between KO and WT mice. Hepatic Wnt5a gene expression and plasma Wnt5a levels significantly increased after a single CCl4 injection in both mice. Sfrp5 knockout significantly enhanced CCl4 -induced liver fibrosis.

CONCLUSIONS

Our findings demonstrate that Sfrp5 may ameliorate mouse liver fibrosis through inhibition of Wnt5a/Fz2 signalling.

Dynasore enhances the formation of mitochondrial antiviral signalling aggregates and endocytosis-independent NF-κB activation

BACKGROUND AND PURPOSE

Dynasore has been used extensively as an inhibitor of clathrin-mediated endocytosis. While studying the role of endocytosis in LPS-induced signalling events, we discovered that dynasore itself induced activation of NF-κB, independently of its effects on endocytosis and without involving the Toll-like receptor 4 signalling pathways. The purpose of this study was to characterize this novel effect and to explore the underlying mechanism of action.

EXPERIMENTAL APPROACH

We utilized gel electrophoresis, microscopy, gene knockdown and luciferase-based promoter activity to evaluate the effect of dynasore on cell signalling pathways and to delineate the mechanisms involved in its effects,

KEY RESULTS

Dynasore activated the NF-κB and IFN-β pathways by activating mitochondrial antiviral signalling protein (MAVS). We showed that MAVS is activated by NOX/Rac and forms high molecular weight aggregates, similar to that observed in response to viral infection. We also demonstrated that dynasore-induced activation of JNK occurs downstream of MAVS and is required for activation of NF-κB and IFN-β.

CONCLUSION AND IMPLICATIONS

These findings demonstrate a novel effect of dynasore on cell signalling. We describe a novel Rac1-, ROS- and MAVS-mediated signalling cascade through which dynasore dramatically activates NF-κB, mimicking the viral induction of this key inflammatory signalling pathway. Our results call attention to the need for a broader interpretation of results when dynasore is used in its traditional fashion as an inhibitor of clathrin-mediated endocytosis. These results suggest the intriguing possibility that dynasore or one of its analogues might be of value as an antiviral therapeutic strategy or vaccine adjuvant.

Wnt5a promotes inflammatory responses via nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways in human dental pulp cells

Wnt5a has been found recently to be involved in inflammation regulation through a mechanism that remains unclear. Immunohistochemical staining of infected human dental pulp and tissue from experimental dental pulpitis in rats showed that Wnt5a levels were increased. In vitro, Wnt5a was increased 8-fold in human dental pulp cells (HDPCs) after TNF-α stimulation compared with control cells. We then investigated the role of Wnt5a in HDPCs. In the presence of TNF-α, Wnt5a further increased the production of cytokines/chemokines, whereas Wnt5a knockdown markedly reduced cytokine/ chemokine production induced by TNF-α. In addition, in HDPCs, Wnt5a efficiently induced cytokine/chemokine expression and, in particular, expression of IL-8 (14.5-fold) and CCL2 (25.5-fold), as assessed by a Luminex assay. The cytokine subsets regulated by Wnt5a overlap partially with those induced by TNF-α. However, no TNF-α and IL-1β was detected after Wnt5a treatment. We then found that Wnt5a alone and the supernatants of Wnt5a-treated HDPCs significantly increased macrophage migration, which supports a role for Wnt5a in macrophage recruitment and as an inflammatory mediator in human dental pulp inflammation. Finally, Wnt5a participates in dental pulp inflammation in a MAPK-dependent (p38-, JNK-, and ERK-dependent) and NF-κB-dependent manner. Our data suggest that Wnt5a, as an inflammatory mediator that drives the integration of cytokines and chemokines, acts downstream of TNF-α.

Wnt5a: a player in the pathogenesis of atherosclerosis and other inflammatory disorders

OBJECTIVE

The objective of this article is to review the current literature on Wnt5a and its signaling mechanism, along with its role in atherosclerosis. In addition, the significance of Wnt5a as a diagnostic marker and a potential therapeutic target is reviewed. Wnt5a, a secreted glycoprotein, belongs to a family of highly conserved proteins that regulate important processes such as cell fate specification, embryonic development, cell proliferation, migration, and differentiation in a variety of organisms. The complexity of Wnt5a signaling lies in the fact that Wnt5a can bind to different classes of frizzled receptors, receptor tyrosine kinase-like orphan receptor 2, as well as co-receptors such as low density lipoprotein receptor-related protein 5/6. Wnt5a signals primarily through the non-canonical pathway, where it mediates cell proliferation, adhesion, and movement. However, the role of Wnt5a in canonical signaling is still unresolved. Depending on the receptor availability, Wnt5a can serve to activate or inhibit the canonical Wnt signaling pathway. Due to the promiscuous nature of Wnt5a, it has been extremely difficult to fully understand its signaling mechanism. Wnt5a has recently emerged as a macrophage effector molecule that triggers inflammation. Perturbations in Wnt5a signaling have been reported in several inflammatory diseases, particularly in sepsis, rheumatoid arthritis, and atherosclerosis.

CONCLUSION

Both existing and emerging evidence suggests that the expression of Wnt5a is always up-regulated in these, and possibly other inflammatory disorders. This knowledge can be useful for targeting Wnt5a and/or its receptor and downstream signaling molecules for therapeutic intervention in inflammatory disorders.

TGF-β-activated kinase 1 (TAK1) signaling regulates TGF-β-induced WNT-5A expression in airway smooth muscle cells via Sp1 and β-catenin

WNT-5A, a key player in embryonic development and post-natal homeostasis, has been associated with a myriad of pathological conditions including malignant, fibroproliferative and inflammatory disorders. Previously, we have identified WNT-5A as a transcriptional target of TGF-β in airway smooth muscle cells and demonstrated its function as a mediator of airway remodeling. Here, we investigated the molecular mechanisms underlying TGF-β-induced WNT-5A expression. We show that TGF-β-activated kinase 1 (TAK1) is a critical mediator of WNT-5A expression as its pharmacological inhibition or siRNA-mediated silencing reduced TGF-β induction of WNT-5A. Furthermore, we show that TAK1 engages p38 and c-Jun N-terminal kinase (JNK) signaling which redundantly participates in WNT-5A induction as only simultaneous, but not individual, inhibition of p38 and JNK suppressed TGF-β-induced WNT-5A expression. Remarkably, we demonstrate a central role of β-catenin in TGF-β-induced WNT-5A expression. Regulated by TAK1, β-catenin is required for WNT-5A induction as its silencing repressed WNT-5A expression whereas a constitutively active mutant augmented basal WNT-5A abundance. Furthermore, we identify Sp1 as the transcription factor for WNT-5A and demonstrate its interaction with β-catenin. We discover that Sp1 is recruited to the WNT-5A promoter in a TGF-β-induced and TAK1-regulated manner. Collectively, our findings describe a TAK1-dependent, β-catenin- and Sp1-mediated signaling cascade activated downstream of TGF-β which regulates WNT-5A induction.

Antitumor efficacy of α-solanine against pancreatic cancer in vitro and in vivo

α-solanine, a steroidal glycoalkaloid in potato, was found to have proliferation-inhibiting and apoptosis-promoting effect on multiple cancer cells, such as clone, liver, melanoma cancer cells. However, the antitumor efficacy of α-solanine on pancreatic cancer has not been fully evaluated. In this study, we inquired into the anti-carcinogenic effect of α-solanine against human pancreatic cancer cells. In the present study, we investigated the anti-carcinogenic effect of α-solanine against human pancreatic cancer cells. In vitro, α-solanine inhibited proliferation of PANC-1, sw1990, MIA PaCa-2 cells in a dose-dependent manner, as well as cell migration and invasion with atoxic doses. The expression of MMP-2/9, extracellular inducer of matrix metalloproteinase (EMMPRIN), CD44, eNOS and E-cadherin were suppressed by α-solanine in PANC-1 cells. Moreover, significantly decreased vascular endothelial growth factor (VEGF) expression and tube formation of endothelial cells were discerned following α-solanine treatment. Suppressed phosphorylation of Akt, mTOR, and Stat3, and strengthen phosphorylation of β-catenin was found, along with markedly decreased tran-nuclear of NF-κB, β-catenin and TCF-1. Following the administration of α-solanine (6 µg/g for 2 weeks) in xenograft model, tumor volume and weight were decreased by 61% and 43% (p<0.05) respectively, showing decreased MMP-2/9, PCNA and VEGF expression. In conclusion, α-solanine showed beneficial effects on pancreatic cancer in vitro and in vivo, which may via suppressing the pathway proliferation, angiogenesis and metastasis.

Wnt5a stimulates chemotactic migration and chemokine production in human neutrophils

Wnt5a is a ligand that activates the noncanonical Wnt signaling pathways (β-catenin-independent pathways). Human neutrophils expressed several Wnt5a receptors, such as Frizzled 2, 5 and 8. Stimulation of human neutrophils with Wnt5a caused chemotactic migration and the production of two important chemokines, CXCL8 and CCL2. CCL2 production by Wnt5a was mediated by a pertussis toxin-sensitive G-protein-dependent pathway. Wnt5a also stimulated the phosphorylation of three mitogen-activated protein kinases (MAPKs: ERK, p38 MAPK and JNK) and Akt. Inhibition of ERK, p38 MAPK or JNK by specific inhibitors induced a dramatic reduction in Wnt5a-induced CCL2 production. Supernatant collected from lipopolysaccharide-stimulated macrophages induced neutrophil chemotaxis, which was significantly inhibited by anti-Wnt5a antibody. Our results suggested that Wnt5a may contribute to neutrophil recruitment, mediating the inflammation response.