The Wingless homolog WNT5A and its receptor Frizzled-5 regulate inflammatory responses of human mononuclear cells induced by microbial stimulation

WNT5A regulates the proliferation, apoptosis and stemness of human stem Leydig cells via the β-catenin signaling pathway

Stem Leydig cells (SLCs) are essential for maintaining normal spermatogenesis as the significant component of testis microenvironment and gonadal aging. Although progress has been achieved in the regulation of male germ cells in mammals and humans, it remains unknown about the genes and signaling pathways of human SLCs. Here we have demonstrated, for the first time, that WNT5A (Wnt family member 5a) mediates the proliferation, apoptosis, and stemness of human SLCs, namely NGFR+ Leydig cells. We revealed that NGFR+ Leydig cells expressed NGFR, PDGFRA, NES, NR2F2, and THY1, hallmarks for SLCs. RNA-sequencing showed that WNT5A was expressed at a higher level in human SLCs than non-SLCs, while immunohistochemistry and Western blots further illustrated that WNT5A was predominantly expressed in human SLCs. Notably, CCK-8, EdU and Western blots displayed that WNT5A enhanced the proliferation and DNA synthesis and retained stemness of human SLCs, whereas flow cytometry and TUNEL analyses demonstrated that WNT5A inhibited the apoptosis of these cells. WNT5A knockdown caused an increase in LC lineage differentiation of human SLCs and reversed the effect of WNT5A overexpression on fate decisions of human SLCs. In addition, WNT5A silencing  resulted in the decreases in nuclear translocation of β-catenin and expression levels of c-Myc, CD44, and Cyclin D1. Collectively, these results implicate that WNT5A regulates the proliferation, apoptosis and stemness of human SLCs through the activation of the β-catenin signaling pathway. This study thus provides a novel molecular mechanism underlying the fate determinations of human SLCs, and it offers a new insight into the niche regulation of human testis.

Association Between Wnt Target Genes and Cortical Volumes in Alzheimer's Disease

The disproportionate cortical atrophy is an established biomarker for the pathophysiological process of Alzheimer's disease (AD). However, the genetic basis underlying the cortical atrophy remains poorly defined. Herein, we aim to illustrate the effect of the Wnt target genes on the cortical volumes of AD patients. 82 sporadic AD patients were recruited. All the subjects had history survey, blood biochemical examination, cognitive assessment, MRI morphometry and whole exome sequencing. This report focused on 84 common variants (minor allele frequency > 0.01) of 32 Wnt target genes, including the APC, DAAM1, DACT1, DISC1, LATS2, TLR2, WDR61, and the AXIN, DVL, FZD, LRP, TCF/LEF, WNT family genes. The Wnt target genes showed asymmetric effects on the cortical volumes of AD patients. The right temporal/parietal/occipital cortices were more affected than left temporal/parietal/occipital cortices. Nevertheless, the reverse applied to the frontal cortex. The DACT1 affected the cortical thickness most, followed by the TCF3 and APC. The DACT1 rs698025-GG genotype displayed greater right temporal pole and left medial orbito-frontal gyrus than rs698025-GA genotype (2.4 ± 0.4 vs. 2.0 ± 0.6, P = 0.005; 5.2 ± 0.6 vs. 5.0 ± 0.6, P = 0.001). The brain region most influenced by the Wnt target genes was the right calcarine cortex. In conclusion, the common variants of the Wnt target genes exert asymmetric effects on the cortical volumes of AD patients. The Wnt signaling pathway may play a role in the cortical atrophy of AD patients.

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.

Wnt signaling in periodontitis

OBJECTIVE

This study aimed to evaluate the Wnt/β-catenin signaling pathway activity in gingival samples obtained from patients with periodontitis.

MATERIALS AND METHODS

Fifteen patients with stage III grade B (SIIIGB) and eleven with stage III grade C (SIIIGC) periodontitis were included and compared to 15 control subjects. β-Catenin, Wnt 3a, Wnt 5a, and Wnt 10b expressions were evaluated by Q-PCR. Topographic localization of tissue β-catenin, Wnt 5a, and Wnt 10b was measured by immunohistochemical analysis. TNF-α was used to assess the inflammatory state of the tissues, while Runx2 was used as a mediator of active destruction.

RESULTS

Wnt 3a, Wnt 5a, and Wnt 10b were significantly higher in gingival tissues in both grades of stage 3 periodontitis compared to the control group (p < 0.05). β-Catenin showed intranuclear staining in connective tissue in periodontitis, while it was confined to intracytoplasmic staining in epithelial tissue and the cell walls in the control group. Wnt5a protein expression was elevated in periodontitis, with the most intense staining observed in the connective tissue of SIIIGC samples. Wnt10b showed the highest density in the connective tissue of patients with periodontitis.

CONCLUSIONS

Our findings suggested that periodontal inflammation disrupts the Wnt/β-catenin signaling pathway.

CLINICAL RELEVANCE

Periodontitis disrupts Wnt signaling in periodontal tissues in parallel with tissue inflammation and changes in morphology. This change in Wnt-related signaling pathways that regulate tissue homeostasis in the immunoinflammatory response may shed light on host-induced tissue destruction in the pathogenesis of the periodontal disease.

Canonical and non-canonical functions of NLRP3

BACKGROUND

Since its discovery, NLRP3 is almost never separated from its major role in the protein complex it forms with ASC, NEK7 and Caspase-1, the inflammasome. This key component of the innate immune response mediates the secretion of proinflammatory cytokines IL-1β and IL-18 involved in immune response to microbial infection and cellular damage. However, NLRP3 has also other functions that do not involve the inflammasome assembly nor the innate immune response. These non-canonical functions have been poorly studied. Nevertheless, NLRP3 is associated with different kind of diseases probably through its inflammasome dependent function as through its inflammasome independent functions.

AIM OF THE REVIEW

The study and understanding of the canonical and non-canonical functions of NLRP3 can help to better understand its involvement in various pathologies. In parallel, the description of the mechanisms of action and regulation of its various functions, can allow the identification of new therapeutic strategies.

KEY SCIENTIFIC CONCEPTS OF THE REVIEW

NLRP3 functions have mainly been studied in the context of the inflammasome, in myeloid cells and in totally deficient transgenic mice. However, for several year, the work of different teams has proven that NLRP3 is also expressed in other cell types where it has functions that are independent of the inflammasome. If these studies suggest that NLRP3 could play different roles in the cytoplasm or the nucleus of the cells, the mechanisms underlying NLRP3 non-canonical functions remain unclear. This is why we propose in this review an inventory of the canonical and non-canonical functions of NLRP3 and their impact in different pathologies.

Toll-like receptor-guided therapeutic intervention of human cancers: molecular and immunological perspectives

Toll-like receptors (TLRs) serve as the body's first line of defense, recognizing both pathogen-expressed molecules and host-derived molecules released from damaged or dying cells. The wide distribution of different cell types, ranging from epithelial to immune cells, highlights the crucial roles of TLRs in linking innate and adaptive immunity. Upon stimulation, TLRs binding mediates the expression of several adapter proteins and downstream kinases, that lead to the induction of several other signaling molecules such as key pro-inflammatory mediators. Indeed, extraordinary progress in immunobiological research has suggested that TLRs could represent promising targets for the therapeutic intervention of inflammation-associated diseases, autoimmune diseases, microbial infections as well as human cancers. So far, for the prevention and possible treatment of inflammatory diseases, various TLR antagonists/inhibitors have shown to be efficacious at several stages from pre-clinical evaluation to clinical trials. Therefore, the fascinating role of TLRs in modulating the human immune responses at innate as well as adaptive levels directed the scientists to opt for these immune sensor proteins as suitable targets for developing chemotherapeutics and immunotherapeutics against cancer. Hitherto, several TLR-targeting small molecules (e.g., Pam3CSK4, Poly (I:C), Poly (A:U)), chemical compounds, phytocompounds (e.g., Curcumin), peptides, and antibodies have been found to confer protection against several types of cancers. However, administration of inappropriate doses of such TLR-modulating therapeutics or a wrong infusion administration is reported to induce detrimental outcomes. This review summarizes the current findings on the molecular and structural biology of TLRs and gives an overview of the potency and promises of TLR-directed therapeutic strategies against cancers by discussing the findings from established and pipeline discoveries.

Endothelial Dysfunction in Cardiorenal Conditions: Implications of Endothelial Glucocorticoid Receptor-Wnt Signaling

The endothelium constitutes the innermost lining of the blood vessels and controls blood fluidity, vessel permeability, platelet aggregation, and vascular tone. Endothelial dysfunction plays a key role in initiating a vascular inflammatory cascade and is the pivotal cause of various devastating diseases in multiple organs including the heart, lung, kidney, and brain. Glucocorticoids have traditionally been used to combat vascular inflammation. Endothelial cells express glucocorticoid receptors (GRs), and recent studies have demonstrated that endothelial GR negatively regulates vascular inflammation in different pathological conditions such as sepsis, diabetes, and atherosclerosis. Mechanistically, the anti-inflammatory effects of GR are mediated, in part, through the suppression of Wnt signaling. Moreover, GR modulates the fatty acid oxidation (FAO) pathway in endothelial cells and hence can influence FAO-mediated fibrosis in several organs including the kidneys. This review summarizes the relationship between GR and Wnt signaling in endothelial cells and the effects of the Wnt pathway in different cardiac and renal diseases. Available data suggest that GR plays a significant role in restoring endothelial integrity, and research on endothelial GR-Wnt interactions could facilitate the development of novel therapies for many cardiorenal conditions.

Wnt5a-Flt1 activation contributes to preterm altered cerebral angiogenesis after prenatal inflammation

OBJECTIVE

Intraventricular hemorrhage (IVH) causes morbidity and mortality in preterm infants and prenatal exposure to inflammation contributes to brain injury. Moreover, prenatal exposure to severe inflammation increases the risk of IVH in preterm neonates. The current study investigated whether intrauterine exposure to inflammation affects cerebral angiogenesis and its underlying mechanisms.

METHODS

Wnt5a, flt1, and vascular endothelial growth factor (VEGF)-A levels in cord blood serum (stored in a bio-bank) of the enrolled patients were measured via enzyme-linked immunosorbent assay. A preterm prenatal inflammation exposure model was established in rats by intraperitoneal injection intraperitoneally during pregnancy. Angiogenesis of cerebral tissue was analyzed using immunohistochemistry. Wnt5a, flt1, and VEGF-A expression levels were measured via immunohistochemistry, immunofluorescence, or western blotting. The correlation between Wnt5a and flt1 expression and the cerebral vessel area was also analyzed.

RESULTS

The Wnt5a and flt1 levels in the cord blood serum were significantly higher in the amnionitis group than in the non-amnionitis group. The VEGF-A level in the cord blood serum was significantly lower in the amnionitis group. In the rat model, preterm rats in the prenatal inflammation group exhibited increased microglial cell infiltration and decreased vessel area and diameter in the cerebral tissue compared to the control group. Wnt5a was located in microglial cells, and Wnt5a and flt1 expression in brain tissue significantly increased after prenatal lipopolysaccharide (LPS) exposure. VEGF-A expression declined after prenatal LPS exposure. The cerebral vessel area was negatively correlated with Wnt5a and flt1 expression.

CONCLUSION

Disordered cerebral angiogenesis is associated with increased Wnt5a-Flt1 activation in microglial cells after exposure to intrauterine inflammation.

Insilco prediction of the role of the FriZZled5 gene in colorectal cancer

INTRODUCTION

In this study, we aimed to elucidate the crosstalk between the Wnt/β-catenin signaling pathway and colorectal cancer (CRC) associated with inflammatory bowel disease (IBD) using a bioinformatics analysis of putative common biomarkers and a systems biology approach.

MATERIALS AND METHODS

The following criteria were used to search the GEO and ArrayExpress databases for terms related to CRC and IBD: 1. The dataset containing the transcriptomic data, and 2. Untreated samples by medications or drugs. A total of 42 datasets were selected for additional analysis. The GEO2R identified the differentially expressed genes. The genes involved in the Wnt signaling pathway were extracted from the KEGG database. Enrichment analysis and miRNA target prediction were conducted through the ToppGene online tool.

RESULTS

In CRC datasets, there were 1168 up- and 998 down-regulated probes, whereas, in IBD datasets, there were 256 up- and 200 down-regulated probes. There were 65 upregulated and 57 downregulated genes shared by CRC and IBD. According to KEGG, there were 166 genes in the Wnt pathway. FriZZled5 (FZD5) was a down-regulated gene in both CRC and IBD, as determined by the intersection of CRC- and IBD-related DEGs with the Wnt pathway. It was also demonstrated that miR-191, miR-885-5p, miR-378a-3p, and miR-396-3p affect the FriZZled5 gene expression.

CONCLUSION

It is possible that increased expression of miR-191 and miR-885-5p, or decreased expression of miR-378a -3p and miR396-3, in IBD and CRC results in decreased expression of the FZD5 gene. Based on the function of this gene, FZD5 may be a potential therapeutic target in IBD that progresses to CRC.

Monocyte-endothelial cell interactions in vascular and tissue remodeling

Monocytes are circulating leukocytes of innate immunity derived from the bone marrow that interact with endothelial cells under physiological or pathophysiological conditions to orchestrate inflammation, angiogenesis, or tissue remodeling. Monocytes are attracted by chemokines and specific receptors to precise areas in vessels or tissues and transdifferentiate into macrophages with tissue damage or infection. Adherent monocytes and infiltrated monocyte-derived macrophages locally release a myriad of cytokines, vasoactive agents, matrix metalloproteinases, and growth factors to induce vascular and tissue remodeling or for propagation of inflammatory responses. Infiltrated macrophages cooperate with tissue-resident macrophages during all the phases of tissue injury, repair, and regeneration. Substances released by infiltrated and resident macrophages serve not only to coordinate vessel and tissue growth but cellular interactions as well by attracting more circulating monocytes (e.g. MCP-1) and stimulating nearby endothelial cells (e.g. TNF-α) to expose monocyte adhesion molecules. Prolonged tissue accumulation and activation of infiltrated monocytes may result in alterations in extracellular matrix turnover, tissue functions, and vascular leakage. In this review, we highlight the link between interactions of infiltrating monocytes and endothelial cells to regulate vascular and tissue remodeling with a special focus on how these interactions contribute to pathophysiological conditions such as cardiovascular and chronic liver diseases.

Characterization of Inflammatory Signals in BV-2 Microglia in Response to Wnt3a

Activation of microglia is one of the pathological bases of neuroinflammation, which involves various diseases of the central nervous system. Inhibiting the inflammatory activation of microglia is a therapeutic approach to neuroinflammation. In this study, we report that activation of the Wnt/β-catenin signaling pathway in a model of neuroinflammation in Lipopolysaccharide (LPS)/IFN-γ-stimulated BV-2 cells can result in inhibition of production of nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Activation of the Wnt/β-catenin signaling pathway also results in inhibition of the phosphorylation of nuclear factor-κB (NF-κB) and extracellular signal-regulated kinase (ERK) in the LPS/IFN-γ-stimulated BV-2 cells. These findings indicate that activation of the Wnt/β-catenin signaling pathway can inhibit neuroinflammation through downregulating the pro-inflammatory cytokines including iNOS, TNF-α, and IL-6, and suppress NF-κB/ERK-related signaling pathways. In conclusion, this study indicates that the Wnt/β-catenin signaling activation may play an important role in neuroprotection in certain neuroinflammatory diseases.

Transcriptomic analysis of human cytomegalovirus to survey the indirect effects on renal transplant recipients

Post-transplant human cytomegalovirus (HCMV) viremia has been linked to adverse "indirect effects" among transplant patients. HCMV-created immunomodulatory mechanisms could be associated with the indirect effects.

OBJECTIVE

In the present study, the RNA-Seq whole transcriptome of renal transplant (RT) patients was analyzed to seek the underlying pathobiologic pathways associated with the long-term indirect effects of HCMV.

METHODS

To investigate the activated biological pathways in HCMV infection, total RNA was extracted from PBMCs of 2 RT patients with active HCMV and 2 RT patients without infection and then were sequenced using RNA-Seq. The resulted raw data were analyzed by conventional RNA-Seq software to determine the Differentially Expressed Genes (DEGs). Afterward, Gene Ontology (GO) and pathway enrichment analyses were conducted to determine the enriched pathways and biological processes by DEGs. Eventually, the relative expressions of some significant genes were validated in the twenty external RT patients.

RESULT

The analysis of RNA-Seq data related to RT patients with HCMV active viremia led to the identification of 140 up-regulated and 100 down-regulated DEGs. KEGG pathway analysis revealed the enrichment of DEGs in IL18 signaling, AGE-RAGE signaling pathway in diabetic complications, signaling by GPCR, Platelet activation, signaling and aggregation, Estrogen signaling pathway and signaling by Wnt due to HCMV infection. The expression levels of six genes involved in enriched pathways including F3, PTX3, ADRA2B, GNG11, GP9, HBEGF were then verified using RT-qPCR. The results were in consistent with RNA-Seq resultsoutcomes.

CONCLUSION

This study specifies some pathobiological pathways which are activated in HCMV active infection and could be linked to the adverse indirect effects caused by HCMV infection in transplant patients.

Secreted Frizzled Related Protein 5 (SFRP5) Serum Levels Are Decreased in Critical Illness and Sepsis and Are Associated with Short-Term Mortality

Sepsis is a major health burden with insufficiently understood mechanisms of inflammation and immune paralysis, leading to a life-threatening critical illness. The secreted frizzled related protein 5 (SFRP5) acts as an anti-inflammatory adipokine by antagonizing the Wnt5a pathway. The aim of this study was to elucidate the role of SFRP5 in critical illness and sepsis and to determine its value as a prognostic biomarker for mortality. We analyzed SFRP5 serum concentrations of 223 critically ill patients at admission to a medical intensive care unit (ICU) and compared those to 24 healthy individuals. SFRP5 serum concentrations were significantly decreased in critical illness as compared to healthy controls (24.66 vs. 100 ng/mL, p = 0.029). Even lower serum concentrations were found in septic as compared to nonseptic critically ill patients (19.21 vs. 32.83 ng/mL, p = 0.031). SFRP5 concentrations correlated with liver disease, age, anti-inflammation, and metabolic parameters. Furthermore, patients with sepsis recovered levels of SFRP5 in the first week of ICU treatment. SFRP5 levels at admission predicted short-term mortality in critically ill but not in septic patients. This study points to the role of the anti-inflammatory mediator SFRP5 not only in sepsis but also in nonseptic critically ill patients and associates high levels of SFRP5 to worse outcomes, predominantly in nonseptic critically ill patients.

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.

Wnt5a regulates autophagy in Bacille Calmette-Guérin (BCG)-Infected pulmonary epithelial cells

Autophagy functions as a critical process that can suppress the proliferation of Mycobacterium tuberculosis (Mtb) within infected host cells. Wnt5a is a secreted protein that plays a range of physiological functions, activating several signaling pathways and thereby controlling cellular responses to particular stimuli. The importance of Wnt5a as a regulator of protection against Mtb infection, however, has yet to be fully characterized. Here, changes in murine pulmonary epithelial-like TC-1 cell morphology, autophagy, the Wnt/Ca²⁺ signaling pathway, and the mTOR autophagy pathway were analyzed following infection with the Mtb model pathogen Bacille Calmette-Guerin (BCG) in order to understand the regulatory role of Wnt5a in this context. These experiments revealed that Wnt5a was upregulated and autophagy was enhanced in TC-1 cells infected with BCG, and Wnt5a overexpression was found to drive BCG-induced autophagy in these cells upon infection, whereas the inhibition or knockdown of Wnt5a yielded the opposite effect. At the mechanistic level, Wnt5a was found to mediate non-canonical Wnt/Ca²⁺ signaling and thereby inhibit mTOR-dependent pathway activation, promoting autophagic induction within BCG-infected TC-1 cells. These data offer new insight regarding how Wnt5a influences Mtb-induced autophagy within pulmonary epithelial cells, providing a foundation for further research exploring the immunological control of this infection through the modulation of autophagy.

In-depth systems biological evaluation of bovine alveolar macrophages suggests novel insights into molecular mechanisms underlying Mycobacterium bovis infection

OBJECTIVE

Bovine tuberculosis (bTB) is a chronic respiratory infectious disease of domestic livestock caused by intracellular Mycobacterium bovis infection, which causes ~$3 billion in annual losses to global agriculture. Providing novel tools for bTB managements requires a comprehensive understanding of the molecular regulatory mechanisms underlying the M. bovis infection. Nevertheless, a combination of different bioinformatics and systems biology methods was used in this study in order to clearly understand the molecular regulatory mechanisms of bTB, especially the immunomodulatory mechanisms of M. bovis infection.

METHODS

RNA-seq data were retrieved and processed from 78 (39 non-infected control vs. 39 M. bovis-infected samples) bovine alveolar macrophages (bAMs). Next, weighted gene co-expression network analysis (WGCNA) was performed to identify the co-expression modules in non-infected control bAMs as reference set. The WGCNA module preservation approach was then used to identify non-preserved modules between non-infected controls and M. bovis-infected samples (test set). Additionally, functional enrichment analysis was used to investigate the biological behavior of the non-preserved modules and to identify bTB-specific non-preserved modules. Co-expressed hub genes were identified based on module membership (MM) criteria of WGCNA in the non-preserved modules and then integrated with protein-protein interaction (PPI) networks to identify co-expressed hub genes/transcription factors (TFs) with the highest maximal clique centrality (MCC) score (hub-central genes).

RESULTS

As result, WGCNA analysis led to the identification of 21 modules in the non-infected control bAMs (reference set), among which the topological properties of 14 modules were altered in the M. bovis-infected bAMs (test set). Interestingly, 7 of the 14 non-preserved modules were directly related to the molecular mechanisms underlying the host immune response, immunosuppressive mechanisms of M. bovis, and bTB development. Moreover, among the co-expressed hub genes and TFs of the bTB-specific non-preserved modules, 260 genes/TFs had double centrality in both co-expression and PPI networks and played a crucial role in bAMs-M. bovis interactions. Some of these hub-central genes/TFs, including PSMC4, SRC, BCL2L1, VPS11, MDM2, IRF1, CDKN1A, NLRP3, TLR2, MMP9, ZAP70, LCK, TNF, CCL4, MMP1, CTLA4, ITK, IL6, IL1A, IL1B, CCL20, CD3E, NFKB1, EDN1, STAT1, TIMP1, PTGS2, TNFAIP3, BIRC3, MAPK8, VEGFA, VPS18, ICAM1, TBK1, CTSS, IL10, ACAA1, VPS33B, and HIF1A, had potential targets for inducing immunomodulatory mechanisms by M. bovis to evade the host defense response.

CONCLUSION

The present study provides an in-depth insight into the molecular regulatory mechanisms behind M. bovis infection through biological investigation of the candidate non-preserved modules directly related to bTB development. Furthermore, several hub-central genes/TFs were identified that were significant in determining the fate of M. bovis infection and could be promising targets for developing novel anti-bTB therapies and diagnosis strategies.

Shared signaling pathways and targeted therapy by natural bioactive compounds for obesity and type 2 diabetes

Epidemiological evidence showed that patients suffering from obesity and T2DM are significantly at higher risk for chronic low-grade inflammation, oxidative stress, nonalcoholic fatty liver (NAFLD) and intestinal flora imbalance. Increasing evidence of pathological characteristics illustrates that some common signaling pathways participate in the occurrence, progression, treatment, and prevention of obesity and T2DM. These signaling pathways contain the pivotal players in glucose and lipid metabolism, e.g., AMPK, PI3K/AKT, FGF21, Hedgehog, Notch, and WNT; the inflammation response, for instance, Nrf2, MAPK, NF- kB, and JAK/STAT. Bioactive compounds from plants have emerged as key food components related to healthy status and disease prevention. They can act as signaling molecules to initiate or mediate signaling transduction that regulates cell function and homeostasis to repair and re-functionalize the damaged tissues and organs. Therefore, it is crucial to continuously investigate bioactive compounds as sources of new pharmaceuticals for obesity and T2DM. This review provides comprehensive information of the commonly shared signaling pathways between obesity and T2DM, and we also summarize the therapeutic bioactive compounds that may serve as anti-obesity and/or anti-diabetes therapeutics by regulating these associated pathways, which contribute to improving glucose and lipid metabolism, attenuating inflammation.

Wingless-related integration site (WNT) signaling is activated during the inflammatory response upon cardiac surgery: A translational study

Objective

Cardiac surgery and the use of cardiopulmonary bypass initiate a systemic inflammatory response. Wingless-related integration site (WNT) signaling is part of the innate immunity and has been attributed a major role in the regulation of inflammation. In preclinical research, WNT-5a may sustain an inflammatory response and cause endothelial dysfunction. Our aim was to investigate WNT signaling after cardiac surgery and its association with postoperative inflammation (Clinicaltrials.gov, NCT04058496).

Methods

In this prospective, single-center, observational study, 64 consecutive patients for coronary artery bypass grafting (CABG) ± valve surgery were assigned into three groups: off-pump CABG (n = 28), on-pump CABG (n = 16) and combined valve-CABG surgery (n = 20). Blood samples were acquired before surgery, at intensive care unit (ICU) admission and 4, 8, and 48 h thereafter. Plasma concentrations of WNT-5a and its antagonists Secreted frizzled-related protein 1 (sFRP-1), Secreted frizzled-related protein 5 (sFRP-5), and WNT inhibitory factor 1 (WIF-1) were determined by enzyme-linked immunosorbent assay. In addition, plasma concentrations of six inflammatory cytokines were measured by multiplex immunoassay. Parameters were analyzed for evolution of plasma concentration over time, interactions, intergroup differences, and association with clinical outcome parameters.

Results

At baseline, WNT-5a, sFRP-1, and WIF-1 were present in a minimal concentration, while sFRP-5 was elevated. A higher baseline value of WNT-5a, sFRP-5, and WIF-1 resulted in higher subsequent values of the respective parameter. At ICU admission, WNT-5a and sFRP-5 reached their maximum and minimum value, respectively. WIF-1 decreased over time and was lowest 8 h after surgery. sFRP-1 changed minimally over time. While WNT-5a returned to the baseline within 48 h, sFRP-5 and WIF-1 did not reach their baseline value at 48 h. Of the investigated WNT system components, only WIF-1 partially reflected the severity of surgery. WNT-5a and WIF-1 had an impact on postoperative fluid balance and noradrenaline requirement.

Conclusion

WNT-5a, sFRP-5, and WIF-1 are part of the systemic inflammatory response after cardiac surgery. WNT-5a peaks immediately after cardiac surgery and returns to baseline within 48 h, presumably modulated by its antagonist sFRP-5. Based on this translational study, WNT-5a antagonism may be further investigated to assess potentially beneficial effects in patients with a dysregulated inflammation after cardiac surgery.

Wnt5A signaling supports antigen processing and CD8 T cell activation

Antigen processing and antigen-specific CD8 T cell activation form part and parcel of cell-mediated immunity to infections. Yet, several lacunae remain in our understanding of how antigen processing and CD8 T cell response are coordinated. In this study, using mouse bone marrow-derived dendritic cells (BMDC) as antigen-presenting cells and Ovalbumin (OVA)/DQ-Ovalbumin (DQ-OVA) as model antigen we demonstrated that Wnt5A signaling in BMDC supports antigen processing/presentation and concomitant CD8 T cell activation through regulation of actin and proteasome dynamics. Recombinant Wnt5A conditioning of BMDC and associated actin assembly facilitated DQ-OVA processing, which was inhibited by the proteasome inhibitor MG132. Moreover, Wnt5A depletion led to a significant reduction in OVA processing and presentation. Impaired DQ-OVA processing in Wnt5A depleted BMDC correlated with altered dynamics of both actin and the proteasome regulator PA28α-PA28β, and reduced association of DQ-OVA with actin and proteasome subunits. Inhibited OVA processing/presentation in the Wnt5A depleted BMDC also resulted in subdued activation of OVA-sensitized CD8 T cells in co-culture with the BMDC. In concurrence with these findings, we demonstrated reduced OVA processing and impaired CD8 T cell response to OVA immunization in Wnt5A heterozygous mice lacking a copy of the Wnt5A gene in comparison to the wild-type cohorts. Taken together, our results reveal a crucial requirement of Wnt5A signaling in antigen processing/presentation and CD8 T cell activation, thus unveiling a vital regulatory node of cell-mediated immunity, unidentified thus far.

Convergence of signalling pathways in innate immune responses and genetic forms of Parkinson's disease

In recent years progress in molecular biology and genetics have advanced our understanding of neurological disorders and highlighted synergistic relationships with inflammatory and age-related processes. Parkinson's disease (PD) is a common neurodegenerative disorder that is characterized by loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Increasing extensive evidence supports the contribution of genetic risk variants and inflammation in the pathobiology of this disease. Functional and genetic studies demonstrate an overlap between genes linked to increased risk for PD and autoimmune diseases. Variants identified in loci adjacent to LRRK2, GBA, and HLA establish a crosstalk between the pathobiologies of the two disease spectra. Furthermore, common signalling pathways associated with the pathogenesis of genetic PD are also relevant to inflammatory signaling include MAPK, NF-κB, Wnt and inflammasome signaling. Importantly, post-mortem analyses of brain and cerebrospinal fluid from PD patients show the accumulation of proinflammatory cytokines. In this review we will focus on the principal mechanisms of genetic, inflammatory and age-related risk that intersect in the pathogenesis of PD.

TLR/WNT: A Novel Relationship in Immunomodulation of Lung Cancer

The most frequent cause of death by cancer worldwide is lung cancer, and the 5-year survival rate is still very poor for patients with advanced stage. Understanding the crosstalk between the signaling pathways that are involved in disease, especially in metastasis, is crucial to developing new targeted therapies. Toll-like receptors (TLRs) are master regulators of the immune responses, and their dysregulation in lung cancer is linked to immune escape and promotes tumor malignancy by facilitating angiogenesis and proliferation. On the other hand, over-activation of the WNT signaling pathway has been reported in lung cancer and is also associated with tumor metastasis via induction of Epithelial-to-mesenchymal-transition (EMT)-like processes. An interaction between both TLRs and the WNT pathway was discovered recently as it was found that the TLR pathway can be activated by WNT ligands in the tumor microenvironment; however, the implications of such interactions in the context of lung cancer have not been discussed yet. Here, we offer an overview of the interaction of TLR-WNT in the lung and its potential implications and role in the oncogenic process.

Signaling pathways and targeted therapy for myocardial infarction

Although the treatment of myocardial infarction (MI) has improved considerably, it is still a worldwide disease with high morbidity and high mortality. Whilst there is still a long way to go for discovering ideal treatments, therapeutic strategies committed to cardioprotection and cardiac repair following cardiac ischemia are emerging. Evidence of pathological characteristics in MI illustrates cell signaling pathways that participate in the survival, proliferation, apoptosis, autophagy of cardiomyocytes, endothelial cells, fibroblasts, monocytes, and stem cells. These signaling pathways include the key players in inflammation response, e.g., NLRP3/caspase-1 and TLR4/MyD88/NF-κB; the crucial mediators in oxidative stress and apoptosis, for instance, Notch, Hippo/YAP, RhoA/ROCK, Nrf2/HO-1, and Sonic hedgehog; the controller of myocardial fibrosis such as TGF-β/SMADs and Wnt/β-catenin; and the main regulator of angiogenesis, PI3K/Akt, MAPK, JAK/STAT, Sonic hedgehog, etc. Since signaling pathways play an important role in administering the process of MI, aiming at targeting these aberrant signaling pathways and improving the pathological manifestations in MI is indispensable and promising. Hence, drug therapy, gene therapy, protein therapy, cell therapy, and exosome therapy have been emerging and are known as novel therapies. In this review, we summarize the therapeutic strategies for MI by regulating these associated pathways, which contribute to inhibiting cardiomyocytes death, attenuating inflammation, enhancing angiogenesis, etc. so as to repair and re-functionalize damaged hearts.

Correlation of plasma and urine Wnt5A with the disease activity and cutaneous lesion severity in patients with systemic lupus erythematosus

Reliable noninvasive biomarkers are needed to accurately assess disease activity and prognosis in patients with systemic lupus erythematosus (SLE). The purpose of this study was to investigate the clinical relevance of Wnt5A with disease activity and severity with cutaneous involvement in particular in SLE patients; its concentrations in plasma and urine were examined and analyzed. In the cross-sectional study, the clinical relevance of Wnt5A protein was evaluated in both plasma and urine of SLE patients and healthy cohorts using commercial enzyme-linked immunosorbent assays (ELISA). Significantly, more abundances of Wnt5A protein were determined in both of plasmas and urines of SLE patients compared to healthy cohorts (p < 0.0001), which were even higher in active disease (AD) SLE patients relative to low disease activity (LDA) SLE patients (p < 0.0001). Meanwhile, the ROC curve analysis demonstrated that the plasma and urine Wnt5A were potential candidate biomarkers for identifying the disease activity and severity in SLE patients. The discriminant function analysis further revealed that the plasma and urine Wnt5A were separated and distinct for AD SLE patients and healthy controls. In consistence, the disease severity was correlated with the plasma and urine Wnt5A as ascertained by CLASI activity score and the prevalence of serositis in SLE patients. These results suggest that Wnt5A, as a summary measure for different inflammatory processes, could be a potential biomarker for accessing the disease activity, and a noninvasive biomarker for evaluating the disease severity in terms of cutaneous involvement in SLE patients.

Vertebrate Wnt5a - At the crossroads of cellular signalling

Wnt signalling is an essential pathway in embryogenesis, differentiation, cell motility, development, and adult tissue homeostasis in vertebrates. The Wnt signalling network can activate several downstream pathways such as the β-catenin-dependent TCF/LEF transcription, the Wnt/planar cell polarity (PCP) pathway, and the Wnt/Calcium pathway. Wnt5a is a vertebrate Wnt ligand that is most often associated with the Wnt/PCP signalling pathway. Wnt5a/PCP signalling has a well-described role in embryogenesis via binding to a receptor complex of Frizzled and its co-receptors to initiate downstream activation of the c-Jun N-terminal kinase (JNK) signalling cascade and the Rho and Rac GTPases, Rho-Kinase (ROCK). This activation results in the cytoskeletal remodelling required for cell polarity, migration, and subsequently, tissue re-arrangement and organ formation. This review will focus on more recent work that has revealed new roles for Wnt5a ligands and consequently, an emerging broader function. This is partly due to our growing understanding of the crosstalk between the Wnt/PCP pathway with both the Wnt/β-catenin pathway and other signalling pathways, and in part due to the identification of novel atypical receptors for Wnt5a that demonstrate a far broader role for this ligand.

Roles of Non-Canonical Wnt Signalling Pathways in Bone Biology

The Wnt signalling pathway is one of the central signalling pathways in bone development, homeostasis and regulation of bone mineral density. It consists of numerous Wnt ligands, receptors and co-receptors, which ensure tight spatiotemporal regulation of Wnt signalling pathway activity and thus tight regulation of bone tissue homeostasis. This enables maintenance of optimal mineral density, tissue healing and adaptation to changes in bone loading. While the role of the canonical/β-catenin Wnt signalling pathway in bone homeostasis is relatively well researched, Wnt ligands can also activate several non-canonical, β-catenin independent signalling pathways with important effects on bone tissue. In this review, we will provide a thorough overview of the current knowledge on different non-canonical Wnt signalling pathways involved in bone biology, focusing especially on the pathways that affect bone cell differentiation, maturation and function, processes involved in bone tissue structure regulation. We will describe the role of the two most known non-canonical pathways (Wnt/planar cell polarity pathways and Wnt/Ca2+ pathway), as well as other signalling pathways with a strong role in bone biology that communicate with the Wnt signalling pathway through non-canonical Wnt signalling. Our goal is to bring additional attention to these still not well researched but important pathways in the regulation of bone biology in the hope of prompting additional research in the area of non-canonical Wnt signalling pathways.

Inhibition of BCL9 Modulates the Cellular Landscape of Tumor-Associated Macrophages in the Tumor Immune Microenvironment of Colorectal Cancer

Tumor-associated macrophages (TAMs) are an indispensable part of the tumor microenvironment (TME), and they likely play a negative rather than positive role in cancer treatment. However, the cellular landscape and transcriptional profile regulation of TAMs in the case of tumor gene inactivation or chemical interference remains unclear. The B-cell lymphoma 9/B-cell lymphoma 9-like (BCL9/BCL9L) is a critical transcription co-factor of β-catenin. Suppression of Bcl9 inhibits tumor growth in mouse models of colorectal cancer (CRC). Here, we studied the TAMs of CRC by single-cell sequencing. Bcl9 depletion caused macrophage polarization inhibition from M0 to M2 and changed the CRC TME, which further interferes with the inflammation of M0 and M1. The transcription factor regulating these processes may be related to the Wnt signaling pathway from multiple levels. Furthermore, we also found that the cells delineated from monocyte to NK-like non-functioning cells were significantly different in the BCL9-deprived population. Combining these data, we proposed a TAM-to-NK score to evaluate the dynamic balance in TME of monocyte/TAM cells and NK-like non-functioning cells in The Cancer Genome Atlas (TCGA) clinical samples to verify the clinical significance. We demonstrated that the cell type balance and transcription differences of TAMs regulated by BCL9-driven Wnt signaling affected immune surveillance and inflammation of cancer, ultimately affecting patients' prognosis. We thereby highlighted the potential of targeting Wnt signaling pathway through cancer immunotherapy.

WNT16 is Robustly Increased by Oncostatin M in Mouse Calvarial Osteoblasts and Acts as a Negative Feedback Regulator of Osteoclast Formation Induced by Oncostatin M

Background

Bone loss is often observed adjacent to inflammatory processes. The WNT signaling pathways have been implicated as novel regulators of both immune responses and bone metabolism. WNT16 is important for cortical bone mass by inhibiting osteoclast differentiation, and we have here investigated the regulation of WNT16 by several members of the pro-inflammatory gp130 cytokine family.

Methods

The expression and regulation of Wnt16 in primary murine cells were studied by qPCR, scRNAseq and in situ hybridization. Signaling pathways were studied by siRNA silencing. The importance of oncostatin M (OSM)-induced WNT16 expression for osteoclastogenesis was studied in cells from Wnt16-deficient and wild-type mice.

Results

We found that IL-6/sIL-6R and OSM induce the expression of Wnt16 in primary mouse calvarial osteoblasts, with OSM being the most robust stimulator. The induction of Wnt16 by OSM was dependent on gp130 and OSM receptor (OSMR), and downstream signaling by the SHC1/STAT3 pathway, but independent of ERK. Stimulation of the calvarial cells with OSM resulted in enhanced numbers of mature, oversized osteoclasts when cells were isolated from Wnt16 deficient mice compared to cells from wild-type mice. OSM did not affect Wnt16 mRNA expression in bone marrow cell cultures, explained by the finding that Wnt16 and Osmr are expressed in distinctly different cells in bone marrow, nor was osteoclast differentiation different in OSM-stimulated bone marrow cell cultures isolated from Wnt16^−/- or wild-type mice. Furthermore, we found that Wnt16 expression is substantially lower in cells from bone marrow compared to calvarial osteoblasts.

Conclusion

These findings demonstrate that OSM is a robust stimulator of Wnt16 mRNA in calvarial osteoblasts and that WNT16 acts as a negative feedback regulator of OSM-induced osteoclast formation in the calvarial bone cells, but not in the bone marrow.

Overcoming Immunotherapy Resistance by Targeting the Tumor-Intrinsic NLRP3-HSP70 Signaling Axis

Simple Summary

The tumor-intrinsic NLRP3 inflammasome is a newly recognized player in the regulation of tumor-directed immune responses and promises to provide fresh insight into how tumors respond to immunotherapy. This brief review discusses recent data describing how activation of the tumor-intrinsic NLRP3 inflammasome contributes to immune evasion and what this pathway may provide to the field of immuno-oncology both in terms of pharmacologic targets capable of boosting responses to checkpoint inhibitor therapies and predictive biomarkers indicating which tumors may be most susceptible to these new therapeutic strategies.

Abstract

The tumor-intrinsic NOD-like receptor family, pyrin-domain-containing-3 (NLRP3) inflammasome, plays an important role in regulating immunosuppressive myeloid cell populations in the tumor microenvironment (TME). While prior studies have described the activation of this inflammasome in driving pro-tumorigenic mechanisms, emerging data is now revealing the tumor NLRP3 inflammasome and the downstream release of heat shock protein-70 (HSP70) to regulate anti-tumor immunity and contribute to the development of adaptive resistance to anti-PD-1 immunotherapy. Genetic alterations that influence the activity of the NLRP3 signaling axis are likely to impact T cell-mediated tumor cell killing and may indicate which tumors rely on this pathway for immune escape. These studies suggest that the NLRP3 inflammasome and its secreted product, HSP70, represent promising pharmacologic targets for manipulating innate immune cell populations in the TME while enhancing responses to anti-PD-1 immunotherapy. Additional studies are needed to better understand tumor-specific regulatory mechanisms of NLRP3 to enable the development of tumor-selective pharmacologic strategies capable of augmenting responses to checkpoint inhibitor immunotherapy while minimizing unwanted off-target effects. The execution of upcoming clinical trials investigating this strategy to overcome anti-PD-1 resistance promises to provide novel insight into the role of this pathway in immuno-oncology.

M. fortuitum-induced CNS-pathology: Deciphering the role of canonical Wnt signaling, blood brain barrier components and cytokines

Molecular underpinning of mycobacteria-induced CNS-pathology is not well understood. In the present study, zebrafish were infected with Mycobacterium fortuitum and the prognosis of CNS-pathogenesis studied. We observed M. fortuitum triggers extensive brain-pathology. Evans blue extravasation demonstrated compromised blood-brain barrier (BBB) integrity. Further, decreased expression in tight-junction (TJ) and adherens junction complex (AJC) genes were noted in infected brain. Wnt-signaling has emerged as a major player in host-mycobacterial immunity but its involvement/role in brain-infection is not well studied. Sustained expression of wnt2, wnt3a, fzd5, lrp5/6 and β-catenin, with concordant decline in degradation complex components axin, gsk3β and β-catenin regulator capn2a were observed. The surge in ifng1 and tnfa expression preceding il10 and il4 suggested cytokine-interplay critical in M. fortuitum-induced brain-pathology. Therefore, we suggest adult zebrafish as a viable model for studying CNS-pathology and using the same, conclude that M. fortuitum infection is associated with repressed TJ-AJC gene expression and compromised BBB permeability. Our results implicate Wnt/β-catenin pathway in M. fortuitum-induced CNS-pathology wherein Th1-type signals facilitate bacterial clearance and Th2-type signals prevent the disease sequel.

The Role of Macrophages in Kidney Fibrosis

The phenotypic heterogeneity and functional diversity of macrophages confer on them complexed roles in the development and progression of kidney diseases. After kidney injury, bone marrow-derived monocytes are rapidly recruited to the glomerulus and tubulointerstitium. They are activated and differentiated on site into pro-inflammatory M1 macrophages, which initiate Th1-type adaptive immune responses and damage normal tissues. In contrast, anti-inflammatory M2 macrophages induce Th2-type immune responses, secrete large amounts of TGF-β and anti-inflammatory cytokines, transform into αSMA+ myofibroblasts in injured kidney, inhibit immune responses, and promote wound healing and tissue fibrosis. Previous studies on the role of macrophages in kidney fibrosis were mainly focused on inflammation-associated injury and injury repair. Apart from macrophage-secreted profibrotic cytokines, such as TGF-β, evidence for a direct contribution of macrophages to kidney fibrosis is lacking. However, under inflammatory conditions, Wnt ligands are derived mainly from macrophages and Wnt signaling is central in the network of multiple profibrotic pathways. Largely underinvestigated are the direct contribution of macrophages to profibrotic signaling pathways, macrophage phenotypic heterogeneity and functional diversity in relation to kidney fibrosis, and on their cross-talk with other cells in profibrotic signaling networks that cause fibrosis. Here we aim to provide an overview on the roles of macrophage phenotypic and functional diversity in their contribution to pro-fibrotic signaling pathways, and on the therapeutic potential of targeting macrophages for the treatment of kidney fibrosis.

Overexpression of HOXB4 Promotes Protection of Bone Marrow Mesenchymal Stem Cells Against Lipopolysaccharide-Induced Acute Lung Injury Partially Through the Activation of Wnt/β-Catenin Signaling

Purpose

Pulmonary vascular endothelial cell (EC) injury is recognized as one of the pathological factors of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). Bone marrow mesenchymal stem cell (BMSC)-based cytotherapy has attracted substantial attention over recent years as a promising therapeutic approach for ALI/ARDS; however, its use remains limited due to inconsistent efficacy. Currently, gene modification techniques are widely applied to MSCs. In the present study, we aimed to investigate the effect of BMSCs overexpressing Homeobox B4 (HOXB4) on lipopolysaccharide (LPS)-induced EC injury.

Methods

We used LPS to induce EC injury and established EC-BMSC coculture system using transwell chambers. The effect of BMSCs on ECs was explored by detecting EC proliferation, apoptosis, migration, tube formation, and permeability, and determining whether the Wnt/β-catenin pathway is involved in the regulatory mechanism using XAV-939, inhibitor of Wnt/ β-catenin.

Results

As compared to BMSC^WT, BMSC^HOXB4 coculture promoted EC proliferation, migration, and tube formation after LPS stimulation and attenuated LPS-induced EC apoptosis and vascular permeability. Mechanistically, BMSC^HOXB4 coculture prevented LPS-induced EC injury by activating the Wnt/β-catenin pathway, which is partially reversible by XAV-939. When cocultured with BMSC^HOXB4, pro-inflammatory factors were dramatically decreased and anti-inflammatory factors were greatly increased in the EC medium compared to those in the LPS group (P<0.05). Additionally, when compared to BMSC^WT coculture, the BMSC^HOXB4 coculture showed an enhanced modulation of IL-6, TNF-α, and IL-10, but there was no statistically significant effect on IL-1β and IL-4.

Conclusion

Coculturing of BMSC^HOXB4 prevented LPS-induced EC injury by reversing the inactivation of the Wnt/β-catenin signaling pathway. An in vivo study remains warranted to ascertain whether engraftment of BMSC^HOXB4 can be an attractive strategy for the treatment of ALI/ARDS.

Upregulation of receptor tyrosine kinase-like orphan receptor 2 in idiopathic pulmonary fibrosis

BACKGROUND/AIMS

Receptor tyrosine kinase-like orphan receptor 2 (ROR2) is a major regulator of Wnt signaling, which is involved in fibroblast dysfunction. Because its role has not been evaluated in idiopathic pulmonary fibrosis (IPF), we examined the clinical implications of ROR2 expression.

METHODS

ROR2 mRNA expression was measured using reverse transcription polymerase chain reaction in lung tissue-derived fibroblasts from IPF patients (n = 14) and from controls (n = 10). ROR2 protein was measured using enzyme-linked immunosorbent assay in primary fibroblasts from IPF patients (n = 14) and controls (n = 10), and in bronchoalveolar lavage (BAL) fluids obtained from normal controls (NC; n = 30). IPF patients (n = 84), and other patients with interstitial lung diseases, including nonspecific interstitial pneumonia (NSIP; n = 10), hypersensitivity pneumonitis (HP; n = 10), and sarcoidosis (n = 10).

RESULTS

ROR2 mRNA and protein levels were significantly higher in IPF fibroblasts than in controls (p = 0.003, p = 0.0017, respectively). ROR2 protein levels in BAL fluids from patients with IPF were significantly higher than in those from NC (p < 0.001), and from patients with NSIP (p = 0.006), HP (p = 0.004), or sarcoidosis (p = 0.004). Receiver operating characteristic curves showed a clear difference between IPF and NC in ROR2 protein level (area under the curve, 0.890; confidence interval, 0.829 to 0.950; p < 0.001). ROR2 protein levels were significantly higher in GAP stage III than in GAP stages I and II (p = 0.016).

CONCLUSION

ROR2 may be related to the development of IPF, and its protein level may be a useful and severity-dependent candidate marker for IPF.

Wnt/β-Catenin Antagonist Pyrvinium Exerts Cardioprotective Effects in Polymicrobial Sepsis Model by Attenuating Calcium Dyshomeostasis and Mitochondrial Dysfunction

Calcium dysregulation and mitochondrial dysfunction are key elements in the development of sepsis-induced cardiac dysfunction. Evidences have suggested that inhibition of Wnt/β-Catenin signalling prevents cardiac dysfunction and remodelling in surgical, hypertension and pressure overload models. The present study investigated the effects of Wnt/β-Catenin inhibitor on calcium overload and mitochondrial dysfunction in rat sepsis model of cardiomyopathy. Induction of sepsis by cecal ligation puncture (CLP) resulted in the up-regulation of cardiac β-catenin transcriptional levels and cardiac dysfunction depicted by increased serum lactate dehydrogenase, CK-MB levels reduced maximum (dp/dt max.) and minimum developed pressure (dp/dt min.), increased LVEsDP and relaxation constant tau values. Moreover, oxidative and inflammatory stress, immune cell infiltration, increased myeloperoxidase activity, enhanced caspase-3 activity and fibronectin protein levels were observed in septic rat's heart. Also, septic rat's heart displayed mitochondrial dysfunction due to mPTP opening, increased calcium up-regulation in left ventricular apex tissues and whole heart, increased collagen staining, necrosis and structural damage. Pre-treatment with Wnt/β-Catenin antagonist attenuated sepsis-induced serum and tissue biochemical changes, cardiac dysfunction and structural alterations by inhibiting mitochondrial mPTP opening and restricting calcium overloading in cardiac tissue.

Wnt5a in cancer-associated fibroblasts promotes colorectal cancer progression

Cancer-associated fibroblasts (CAFs) are a major component of the tumor microenvironment and have been shown to promote cancer aggressiveness. In our previous study, analysis of expression profiles obtained from paired CAFs and normal fibroblasts from colorectal cancer (CRC) tissue revealed that gene sets related to the Wnt signaling pathway were highly enriched in colorectal CAFs. Furthermore, among the components of the β-catenin-independent Wnt pathway, Wnt5a was highly expressed in CAFs. Since Wnt5a is considered to be a regulator of CRC progression in CAFs, we performed immunohistochemical analysis on Wnt5a in 171 patients who underwent surgery for CRC. Positive staining for Wnt5a was often found in cancer stroma, particularly in fibromatous areas, although the immunoreactivity for Wnt5a was weak in cancer cells. Wnt5a status in CAFs was significantly associated with tumor size, depth of invasion, lymphatic and vascular invasion, lymph node metastasis, TNM stage, and recurrence. Subsequent in vitro analyses using human recombinant Wnt5a protein revealed that cancer cell proliferation and migration were significantly increased by stimulation with Wnt5a. Our findings suggest that Wnt5a-derived CAFs play a crucial role in CRC progression and have potential as a target of anti-cancer therapies.

Crosstalk between Wnt/β-catenin signaling and NF-κB signaling contributes to apical periodontitis

In physiology conditions, the crosstalk of signaling pathways has been considered to extend the functions of individual pathways and results in a more complex regulatory network. The Wnt3a/β-catenin and NF-κB signaling pathways have been demonstrated involving in apical periodontitis (AP). As AP progresses, ultimately causes tooth loss. In the present study, we investigate the contribution of the crosstalk between the Wnt3a/β-catenin and NF-κB signaling pathways to the development of AP. Clinically, utilizing 60 human AP and healthy tissues (30 samples for each group), we found that the expression levels of Wnt3a/β-catenin and NF-κB were elevated in the Ap tissues compared to that in the healthy group. To further study the roles of Wnt3a/β-catenin and NF-κB signaling pathways in the development of AP, and the contribution of the crosstalk between these two signaling pathways to AP, we established the AP animal model and observed that, first, both pathways are activated in the AP group compared to the control group. Interestingly, by immunoprecipitation and western blot experiments, we revealed that there is greater interaction between NF-κB (phorspho-p65) and β-catenin in AP tissues compared to the control tissues. Importantly, when the NF-κB signaling pathway was blocked by its inhibitor, pyrrolidine dithiocarbamate (PDTC), the activity of the Wnt3a/β-catenin signaling pathway was abolished, and consequently led to the attenuation of the inflammation response in LPS-induced human periodontal ligament cells (hPDLCs). Thus, our data indicate that the crosstalk between Wnt3a/β-catenin and NF-κB signaling pathway contributes to the development of AP, and provide a therapeutic strategy for the treatment of AP as well.

Transcriptional Regulation of Drug Metabolizing CYP Enzymes by Proinflammatory Wnt5A Signaling in Human Coronary Artery Endothelial Cells

Downregulation of drug metabolizing enzymes and transporters by proinflammatory mediators in hepatocytes, enterocytes and renal tubular epithelium is an established mechanism affecting pharmacokinetics. Emerging evidences indicate that vascular endothelial cell expression of drug metabolizing enzymes and transporters may regulate pharmacokinetic pathways in heart to modulate local drug bioavailability and toxicity. However, whether inflammation regulates pharmacokinetic pathways in human cardiac vascular endothelial cells remains largely unknown. The lipid modified protein Wnt5A is emerging as a critical mediator of proinflammatory responses and disease severity in sepsis, hypertension and COVID-19. In the present study, we employed transcriptome profiling and gene ontology analyses to investigate the regulation of expression of drug metabolizing enzymes and transporters by Wnt5A in human coronary artery endothelial cells. Our study shows for the first time that Wnt5A induces the gene expression of CYP1A1 and CYP1B1 enzymes involved in phase I metabolism of a broad spectrum of drugs including chloroquine (the controversial drug for COVID-19) that is known to cause toxicity in myocardium. Further, the upregulation of CYP1A1 and CYP1B1 expression is preserved even during inflammatory crosstalk between Wnt5A and the prototypic proinflammatory IL-1β in human coronary artery endothelial cells. These findings stimulate further studies to test the critical roles of vascular endothelial cell CYP1A1 and CYP1B1, and the potential of vascular-targeted therapy with CYP1A1/CYP1B1 inhibitors in modulating myocardial pharmacokinetics in Wnt5A-associated inflammatory and cardiovascular diseases.

Circulating Wnt Ligands Activate the Wnt Signaling Pathway in Mature Erythrocytes

[Figure: see text].

Functional differences of Toll-like receptor 4 in osteogenesis, adipogenesis and chondrogenesis in human bone marrow-derived mesenchymal stem cells

Multipotent human bone marrow-derived mesenchymal stem cells (hMSCs) are promising candidates for bone and cartilage regeneration. Toll-like receptor 4 (TLR4) is expressed by hMSCs and is a receptor for both exogenous and endogenous danger signals. TLRs have been shown to possess functional differences based on the species (human or mouse) they are isolated from therefore, the effects of knockdown of TLR4 were evaluated in humans during the differentiation of MSCs into bone, fat and chondrocyte cells in vitro. We investigated the expression profile of TLR4 during the differentiation of hMSCs into three different lineages on days 7, 14 and 21 and assessed the differentiation potential of the cells in the presence of lipopolysaccharide (LPS, as an exogenous agonist) and fibronectin fragment III-1c (FnIII-1c, as an endogenous agonist). TLR4 expression increased following the induction of hMSC differentiation into all three lineages. Alkaline phosphatase activity revealed that FnIII-1c accelerated calcium deposition on day 7, whereas LPS increased calcium deposition on day 14. Chondrogenesis increased in the presence of LPS; however, FnIII-1c acted as a reducer in the late stage. TLR4 silencing led to decreased osteogenesis and increased adipogenesis. Furthermore, Wnt5a expression was inversely related to chondrogenesis during the late stage of differentiation. We suggest that understanding the functionality of TLR4 (in the presence of pathogen or stress signal) during the differentiation of hMSCs into three lineages would be useful for MSC-based treatments.

Ehrlichia chaffeensis TRP120 Is a Wnt Ligand Mimetic That Interacts with Wnt Receptors and Contains a Novel Repetitive Short Linear Motif That Activates Wnt Signaling

Ehrlichia chaffeensis expresses the TRP120 multifunctional effector, which is known to play a role in phagocytic entry, on the surface of infectious dense-cored ehrlichiae, but a cognate host receptor has not been identified. We recently reported that E. chaffeensis activates canonical Wnt signaling in monocytes to promote bacterial uptake and intracellular survival and that TRP120 was involved in this activation event. To identify the specific mechanism of pathway activation, we hypothesized that TRP120 is a Wnt signaling ligand mimetic that initiates Wnt pathway activity through direct interaction with the Wnt pathway Frizzled family of receptors. In this study, we used confocal immunofluorescence microscopy to demonstrate very strong colocalization between E. chaffeensis and Fzd2, 4, 5, 7, and 9 as well as coreceptor LRP5 at 1 to 3 h postinfection. Direct binding between TRP120 and multiple Fzd receptors was further confirmed by enzyme-linked immunosorbent assay (ELISA) and surface plasmon resonance (SPR). Interfering RNA knockdown of Wnt receptors, coreceptors, and signaling pathway components significantly reduced E. chaffeensis infection, demonstrating that complex and redundant interactions are involved in Wnt pathway exploitation. We utilized in silico approaches to identify a repetitive short linear motif (SLiM) in TRP120 that is homologous to Wnt ligands and used mutant SLiM peptides and an α-TRP120-Wnt-SLiM antibody to demonstrate that the TRP120 Wnt SLiM activates the canonical Wnt pathway and promotes E. chaffeensis infection. This study reports the first example of bacterial mimicry of Wnt pathway ligands and highlights a pathogenic mechanism with potential for targeting by antimicrobial therapeutics.IMPORTANCE Upon infecting mammalian hosts, Ehrlichia chaffeensis establishes a replicative niche in microbe-eating immune system cells where it expertly orchestrates infection and spread. One of the ways Ehrlichia survives within these phagocytes is by activating evolutionarily conserved signaling pathways including the Wnt pathway; however, the molecular details of pathway hijacking have not been defined. This study is significant because it identifies an ehrlichial protein that directly interacts with components of the Wnt receptor complex, influencing pathway activity and promoting infection. Consequentially, Ehrlichia serves as a unique tool to investigate the intricacies of how pathogens repurpose human immune cell signaling and provides an opportunity to better understand many cellular processes in health and disease. Furthermore, understanding how this bacterium utilizes its small genome to survive within cells that evolved to destroy pathogens will facilitate the development of antibacterial therapeutics that could target Ehrlichia as well as other intracellular agents of human disease.

Coordinated changes in the expression of Wnt pathway genes following human and rat peripheral nerve injury

A human neuroma-in continuity (NIC), formed following a peripheral nerve lesion, impedes functional recovery. The molecular mechanisms that underlie the formation of a NIC are poorly understood. Here we show that the expression of multiple genes of the Wnt family, including Wnt5a, is changed in NIC tissue from patients that underwent reconstructive surgery. The role of Wnt ligands in NIC pathology and nerve regeneration is of interest because Wnt ligands are implicated in tissue regeneration, fibrosis, axon repulsion and guidance. The observations in NIC prompted us to investigate the expression of Wnt ligands in the injured rat sciatic nerve and in the dorsal root ganglia (DRG). In the injured nerve, four gene clusters were identified with temporal expression profiles corresponding to particular phases of the regeneration process. In the DRG up- and down regulation of certain Wnt receptors suggests that nerve injury has an impact on the responsiveness of injured sensory neurons to Wnt ligands in the nerve. Immunohistochemistry showed that Schwann cells in the NIC and in the injured nerve are the source of Wnt5a, whereas the Wnt5a receptor Ryk is expressed by axons traversing the NIC. Taken together, these observations suggest a central role for Wnt signalling in peripheral nerve regeneration.

Mist1+ gastric isthmus stem cells are regulated by Wnt5a and expand in response to injury and inflammation in mice

BACKGROUND AND AIMS

The gastric epithelium undergoes continuous turnover. Corpus epithelial stem cells located in the gastric isthmus serve as a source of tissue self-renewal. We recently identified the transcription factor Mist1 as a marker for this corpus stem cell population that can give rise to cancer. The aim here was to investigate the regulation of the Mist1+ stem cells in the response to gastric injury and inflammation.

METHODS

We used Mist1CreERT;R26-Tdtomato mice in two models of injury and inflammation: the acetic acid-induced ulcer and infection with Helicobacter felis. We analysed lineage tracing at both early (7 to 30 days) and late (30 to 90 days) time points. Mist1CreERT;R26-Tdtomato;Lgr5DTR-eGFP mice were used to ablate the corpus basal Lgr5+ cell population. Constitutional and conditional Wnt5a knockout mice were used to investigate the role of Wnt5a in wound repair and lineage tracing from the Mist1+ stem cells.

RESULTS

In both models of gastric injury, Mist1+ isthmus stem cells more rapidly proliferate and trace entire gastric glands compared with the normal state. In regenerating tissue, the number of traced gastric chief cells was significantly reduced, and ablation of Lgr5+ chief cells did not affect Mist1-derived lineage tracing and tissue regeneration. Genetic deletion of Wnt5a impaired proliferation in the gastric isthmus and lineage tracing from Mist1+ stem cells. Similarly, depletion of innate lymphoid cells, the main source of Wnt5a, also resulted in reduced proliferation and Mist1+ isthmus cell tracing.

CONCLUSION

Gastric Mist1+ isthmus cells are the main supplier of regenerated glands and are activated in part through Wnt5a pathway.

LGK974 suppresses lipopolysaccharide-induced endotoxemia in mice by modulating the crosstalk between the Wnt/β-catenin and NF-κB pathways

Endotoxemia, a type of sepsis caused by gram-negative bacterial endotoxin [i.e., lipopolysaccharide (LPS)], is associated with manifestations such as cytokine storm; failure of multiple organs, including the liver; and a high mortality rate. We investigated the effect and mechanism of action of LGK974, a Wnt signaling inhibitor, in mice with LPS-induced endotoxemia, an animal model of sepsis. LGK974 significantly and dose-dependently increased the survival rate and reduced plasma cytokine levels in mice with LPS-induced endotoxemia. Transcriptome analysis of liver tissues revealed significant changes in the expression of genes associated with the Wnt pathway as well as cytokine and NF-κB signaling during endotoxemia. LGK974 treatment suppressed the activation of NF-κB signaling and cytokine expression as well as the Wnt/β-catenin pathway in the livers of endotoxemic mice. Coimmunoprecipitation of phospho-IκB and β-transducin repeat-containing protein (β-TrCP) was increased in the livers of endotoxemic mice but was reduced by LGK974 treatment. Moreover, LGK974 treatment decreased the coimmunoprecipitation and colocalization of β-catenin and NF-κB, which were elevated in the livers of endotoxemic mice. Our results reveal crosstalk between the Wnt/β-catenin and NF-κB pathways via interactions between β-TrCP and phospho-IκB and between β-catenin and NF-κB during endotoxemia. The results of this study strongly suggest that the crosstalk between the Wnt/β-catenin and NF-κB pathways contributes to the mutual activation of these two pathways during endotoxemia, which results in amplified cytokine production, liver damage and death, and that LGK974 suppresses this vicious amplification cycle by reducing the crosstalk between these two pathways.

Exosomes from TNF-α-treated human gingiva-derived MSCs enhance M2 macrophage polarization and inhibit periodontal bone loss

Mesenchymal stem cell (MSC)–derived exosome plays a central role in the cell-free therapeutics involving MSCs and the contents can be customized under disease-associated microenvironments. However, optimal MSC-preconditioning to enhance its therapeutic potential is largely unknown. Here, we show that preconditioning of gingival tissue-derived MSCs (GMSCs) with tumor necrosis factor-alpha (TNF-α) is ideal for the treatment of periodontitis. TNF-α stimulation not only increased the amount of exosome secreted from GMSCs, but also enhanced the exosomal expression of CD73, thereby inducing anti-inflammatory M2 macrophage polarization. The effect of GMSC-derived exosomes on inflammatory bone loss were examined by ligature-induced periodontitis model in mice. Local injection of GMSC-derived exosomes significantly reduced periodontal bone resorption and the number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts, and these effects were further enhanced by preconditioning of GMSCs with TNF-α. Thus, GMSC-derived exosomes also exhibited anti-osteoclastogenic activity. Receptor activator of NF-κB ligand (RANKL) expression was regulated by Wnt5a in periodontal ligament cells (PDLCs), and exosomal miR-1260b was found to target Wnt5a-mediated RANKL pathway and inhibit its osteoclastogenic activity. These results indicate that significant ability of the TNF-α-preconditioned GMSC-derived exosomes to regulate inflammation and osteoclastogenesis paves the way for establishment of a therapeutic approach for periodontitis.