A caspase-dependent pathway is involved in Wnt/β-catenin signaling promoted apoptosis in Bacillus Calmette-Guerin infected RAW264.7 macrophages

A Protective Role of Canonical Wnt/β-Catenin Pathway in Pathogenic Bacteria-Induced Inflammatory Responses

Inflammation is a complex host defensive response against various disease-associated pathogens. A baseline extent of inflammation is supposed to be tightly associated with a sequence of immune-modulated processes, resulting in the protection of the host organism against pathogen invasion; however, as a matter of fact is that an uncontrolled inflammatory cascade is the main factor responsible for the host damage, accordingly suggesting a significant and indispensable involvement of negative feedback mechanism in modulation of inflammation. Evidence accumulated so far has supported a repressive effect of the canonical Wnt/β-catenin pathway on microbial-triggered inflammation via diverse mechanisms, although that consequence is dependent on the cellular context, types of stimuli, and cytokine environment. It is of particular interest and importance to comprehend the precise way in which the Wnt/β-catenin pathway is activated, due to its essential anti-inflammatory properties. It is assumed that an inflammatory milieu is necessary for initiating and activating this signaling, implying that Wnt activity is responsible for shielding tissues from overwhelming inflammation, thus sustaining a balanced physiological condition against bacterial infection. This review gathers the recent efforts to elucidate the mechanistic details through how Wnt/β-catenin signaling modulates anti-inflammatory responses in response to bacterial infection and its interactions with other inflammatory signals, which warrants further study for the development of specific interventions for the treatment of inflammatory diseases. Further clinical trials from different disease settings are required.

MicroRNA-183 cluster: a promising biomarker and therapeutic target in gastrointestinal malignancies

Small non-coding RNAs (microRNA, miR), powerful epigenetic regulators, were found involved in the regulation of most biological functions via post-translational inhibition of protein expression. Increased expression of pro-oncogenic miRs (known as miR cancer biomarkers) and inhibition of pro-apoptotic miR expression have been demonstrated in different tumors. The recently identified miR-183 was found implicated in gastrointestinal tumor metabolism regulation. Elevated miR-183 expression and cancer-promoting effects were reported in esophageal and colorectal cancers, which was partially contradicted by controversial data observed in gastric cancers. Anti-cancer effect of miR-183 in gastric cancer cells was associated with the Bim-1 and Ezrin genes regulation. Many studies indicated that miR-183 can inhibit tumor suppressor genes in most cell lines, promoting tumor cell proliferation and migration. Increased miR-183 level results in the downregulation of FOXO1, PDCD4, and other tumor suppressor genes in gastrointestinal tumor cells. MiR-183 also influences the signaling of PI3K/AKT/mTOR, Wnt/β-catenin, and Bcl-2/p53 signaling pathways. Mir-183 inhibits apoptosis and autophagy, and promotes epithelial-to-mesenchymal transition, cancer cell proliferation, and migration. Accordingly, gastrointestinal cancer occurrence, development of chemoradiotherapy resistance, recurrence/metastasis, and prognosis were associated with miR-183 expression. The current study assessed reported miR-183 functions and signaling, providing new insights for the diagnosis and treatment of gastrointestinal malignancies.

Repurposing synthetic and natural derivatives induces apoptosis in an orthotopic glioma-induced xenograft model by modulating WNT/β-catenin signaling

BACKGROUND

Glioblastomas arise from multistep tumorigenesis of the glial cells. Despite the current state-of-art treatment, tumor recurrence is inevitable. Among the innovations blooming up against glioblastoma, drug repurposing could provide profound premises for treatment enhancement. While considering this strategy, the efficacy of the repurposed drugs as monotherapies were not up to par; hence, the focus has now shifted to investigate the multidrug combinations.

AIM

To investigate the efficacy of a quadruple-combinatorial treatment comprising temozolomide along with chloroquine, naringenin, and phloroglucinol in an orthotopic glioma-induced xenograft model.

METHODS

Antiproliferative effect of the drugs was assessed by immunostaining. The expression profiles of WNT/β-catenin and apoptotic markers were evaluated by qRT-PCR, immunoblotting, and ELISA. Patterns of mitochondrial depolarization was determined by flow cytometry. TUNEL assay was performed to affirm apoptosis induction. In vivo drug detection study was carried out by ESI-Q-TOF MS analysis.

RESULTS

The quadruple-drug treatment had significantly hampered glioma proliferation and had induced apoptosis by modulating the WNT/β-catenin signaling. Interestingly, the induction of apoptosis was associated with mitochondrial depolarization. The quadruple-drug cocktail had breached the blood-brain barrier and was detected in the brain tissue and plasma samples.

CONCLUSION

The quadruple-drug combination served as a promising adjuvant therapy to combat glioblastoma lethality in vivo and can be probed for translation from bench to bedside.

Molecular Mechanism of Male Sterility Induced by 60Co γ-Rays on Plutella xylostella (Linnaeus)

Plutella xylostella (Linnaeus) is one of the notorious pests causing substantial loses to numerous cruciferous vegetables across many nations. The sterile insect technique (SIT) is a safe and effective pest control method, which does not pollute the environment and does not produce drug resistance. We used proteomics technology and bioinformatics analysis to investigate the molecular mechanisms responsible for the effects of different doses of radiation treatment on the reproductive ability of male P. xylostella. A total of 606 differentially expressed proteins (DEPs) were identified in the 200 Gy/CK group, 1843 DEPs were identified in the 400 Gy/CK group, and 2057 DEPs were identified in the 400 Gy/200 Gy group. The results showed that after 200 Gy irradiation, the testes resisted radiation damage by increasing energy supply, amino acid metabolism and transport, and protein synthesis, while transcription-related pathways were inhibited. After 400 Gy irradiation, the mitochondria and DNA in the testis tissue of P. xylostella were damaged, which caused cell autophagy and apoptosis, affected the normal life activities of sperm cells, and greatly weakened sperm motility and insemination ability. Meanwhile, Western blotting showed that irradiation affects tyrosine phosphorylation levels, which gradually decrease with increasing irradiation dose.

β-Catenin Elicits Drp1-Mediated Mitochondrial Fission Activating the Pro-Apoptotic Caspase-1/IL-1β Signalosome in Aeromonas hydrophila-Infected Zebrafish Macrophages

Canonical Wnt signaling plays a major role in regulating microbial pathogenesis. However, to date, its involvement in A. hydrophila infection is not well known. Using zebrafish (Danio rerio) kidney macrophages (ZKM), we report that A. hydrophila infection upregulates wnt2, wnt3a, fzd5, lrp6, and β-catenin (ctnnb1) expression, coinciding with the decreased expression of gsk3b and axin. Additionally, increased nuclear β-catenin protein accumulation was observed in infected ZKM, thereby suggesting the activation of canonical Wnt signaling in A. hydrophila infection. Our studies with the β-catenin specific inhibitor JW67 demonstrated β-catenin to be pro-apoptotic, which initiates the apoptosis of A. hydrophila-infected ZKM. β-catenin induces NADPH oxidase (NOX)-mediated ROS production, which orchestrates sustained mitochondrial ROS (mtROS) generation in the infected ZKM. Elevated mtROS favors the dissipation of the mitochondrial membrane potential (ΔΨm) and downstream Drp1-mediated mitochondrial fission, leading to cytochrome c release. We also report that β-catenin-induced mitochondrial fission is an upstream regulator of the caspase-1/IL-1β signalosome, which triggers the caspase-3 mediated apoptosis of the ZKM as well as A. hydrophila clearance. This is the first study suggesting a host-centric role of canonical Wnt signaling pathway in A. hydrophila pathogenesis wherein β-catenin plays a primal role in activating the mitochondrial fission machinery, which actively promotes ZKM apoptosis and helps in containing the bacteria.

Wnt/β-catenin signaling pathway-a versatile player in apoptosis and autophagy

The Wnt/β-catenin signaling pathway is a highly conserved pathway that is involved in cell development, proliferation, differentiation, apoptosis and autophagy. Among these processes, apoptosis and autophagy occur physiologically during host defense and the maintenance of intracellular homeostasis. Mounting evidence suggests that the crosstalk between Wnt/β-catenin-regulated apoptosis and autophagy has broad functional significance in various diseases. Herein, we summarize the recent studies in understanding the role of the Wnt/β-catenin signaling pathway in apoptosis and autophagy, and draw the following conclusions: a) For apoptosis, the regulation of Wnt/β-catenin is generally positive. However, a small amount of evidence indicates the presence of a negatively regulated relationship between Wnt/β-catenin and apoptosis; b) Wnt/β-catenin influences the occurrence and development of autophagy by regulating autophagy-related factors, and these factors in turn affect Wnt/β-catenin pathway; c) Wnt/β-catenin always balances the molecular damage caused by the crosstalk between autophagy and apoptosis in a compensatory manner. Understanding the specific role of the Wnt/β-catenin signaling pathway during different stages of autophagy and apoptosis may provide new insights into the progression of related diseases regulated by the Wnt/β-catenin signaling pathway.

Clinical relevance of genetic polymorphisms in WNT signaling pathway (SFRP1, WNT3A, CTNNB1, WIF-1, DKK-1, LRP5, LRP6) on pulmonary tuberculosis in a Chinese population

The present study was performed to evaluate the association of WNT signaling pathway genes variants with pulmonary tuberculosis (PTB) risk in Chinese Han population. Our study subjects were composed of 452 PTB patients and 465 normal controls, and seventeen SNPs of seven genes in WNT signaling pathway (SFRP1, WNT3A, CTNNB1, WIF-1, DKK-1, LRP5, LRP6) were genotyped by SNPscan technique. We found no significant relationship of SFRP1 rs10088390, rs4736958, rs3242, WNT3A rs752107, rs3121310, CTNNB1 rs2293303, rs1798802, rs4135385, WIF-1 rs1026024, rs3782499, DKK-1 rs2241529, rs1569198, LRP5 rs3736228, rs556442, LRP6 rs2302685, rs11054697, rs10743980 polymorphisms with PTB susceptibility. While, WIF-1 rs3782499 variant was associated with susceptibility to PTB under recessive model, and haplotype analysis showed that DKK-1 GA haplotype frequency was significantly increased in PTB patients. The WNT3A rs3121310, CTNNB1 rs2293303 polymorphisms were respectively associated with drug-induced liver injury (DILI), sputum smear-positive in PTB patients. The rs3782499 in WIF-1 gene was related to fever, leukopenia, and the rs1569198 in DKK-1 was linked to sputum smear-positive in PTB patients. In LRP5 gene, rs3736228, rs556442 variants respectively affected the occurrence of DILI, fever, and LRP6 gene rs2302685, rs10743980 variants respectively influenced the development of hypoproteinemia, sputum smear-positive in PTB patients. Our results revealed that WNT signaling pathway genes variation were not associated with the susceptibility to PTB, while WNT3A, CTNNB1, WIF-1, DKK-1, LRP5, LRP6 genetic variations might be closely related to the occurrence of several clinical characteristics of PTB patients.

Exploring Amodiaquine's Repurposing Potential in Breast Cancer Treatment-Assessment of In-Vitro Efficacy & Mechanism of Action

Due to the heterogeneity of breast cancer, current available treatment options are moderately effective at best. Hence, it is highly recommended to comprehend different subtypes, understand pathogenic mechanisms involved, and develop treatment modalities. The repurposing of an old FDA approved anti-malarial drug, amodiaquine (AQ) presents an outstanding opportunity to explore its efficacy in treating majority of breast cancer subtypes. Cytotoxicity, scratch assay, vasculogenic mimicry study, and clonogenic assay were employed to determine AQ's ability to inhibit cell viability, cell migration, vascular formation, and colony growth. 3D Spheroid cell culture studies were performed to identify tumor growth inhibition potential of AQ in MCF-7 and MDAMB-231 cell lines. Apoptosis assays, cell cycle analysis, RT-qPCR assays, and Western blot studies were performed to determine AQ's ability to induce apoptosis, cell cycle changes, gene expression changes, and induction of autophagy marker proteins. The results from in-vitro studies confirmed the potential of AQ as an anti-cancer drug. In different breast cancer cell lines tested, AQ significantly induces cytotoxicity, inhibit colony formation, inhibit cell migration, reduces 3D spheroid volume, induces apoptosis, blocks cell cycle progression, inhibit expression of cancer related genes, and induces LC3BII protein to inhibit autophagy. Our results demonstrate that amodiaquine is a promising drug to repurpose for breast cancer treatment, which needs numerous efforts from further studies.

Repurposing clofazimine for malignant pleural mesothelioma treatment - In-vitro assessment of efficacy and mechanism of action

AIMS

Malignant pleural mesothelioma (MPM) is a rare cancer of lungs' pleural cavity, with minimally effective therapies available. Thus, there exists a necessity for drug repurposing which is an attractive strategy for drug development in MPM. Repurposing of an old FDA-approved anti-leprotic drug, Clofazimine (CFZ), presents an outstanding opportunity to explore its efficacy in treating MPM.

MAIN METHODS

Cytotoxicity, scratch assay, and clonogenic assays were employed to determine CFZ's ability to inhibit cell viability, cell migration, and colony growth. 3D Spheroid cell culture studies were performed to identify tumor growth inhibition potential of CFZ in MSTO-211H cell line. Gene expression analysis was performed using RT-qPCR assays to determine the CFZ's effect of key genes. Western blot studies were performed to determine CFZ's ability to induce apoptosis its effect to induce autophagy marker.

KEY FINDINGS

CFZ showed significant cytotoxicity against both immortalized and primary patient-derived cell lines with IC₅₀ values ranging from 3.4 μM (MSTO-211H) to 7.1 μM (HAY). CFZ significantly impaired MPM cell cloning efficiency, migration, and tumor spheroid formation. 3D Spheroid model showed that CFZ resulted in reduction in spheroid volume. RT-qPCR data showed downregulation of genes β-catenin, BCL-9, and PRDX1; and upregulation of apoptosis markers such as PARP, Cleaved caspase 3, and AXIN2. Additionally, immunoblot analysis showed that CFZ down-regulates the expression of β-catenin (apoptosis induction) and up-regulates p62, LC3B protein II (autophagy inhibition).

SIGNIFICANCE

It can be concluded that CFZ could be a promising molecule to repurpose for MPM treatment which needs numerous efforts from further studies.

Inhibition of ClC-5 suppresses proliferation and induces apoptosis in cholangiocarcinoma cells through the Wnt/β-catenin signaling pathway

Chloride channel-5 (ClC-5), an important branch of the ClC family, is involved in the regulation of the proliferation and cell-fate of a variety of cells, including tumor cells. However, its function in cholangiocarcinoma (CCA) cells remains enigmatic. Here, we discovered that ClC-5 was up-regulated in CCA tissues and CCA cell lines, while ClC-5 silencing inhibited CCA cell proliferation and induced apoptosis. Further mechanism studies revealed that ClC-5 inhibition could inhibit Wnt/β-catenin signaling activity and further activate the mitochondria apoptotic pathway in CCA cells. Furthermore, rescuing Wnt/β-catenin signaling activation eliminated the anti-tumor function of ClC-5 knockdown. Together, our research findings illustrated that ClC-5 inhibition plays an anti-tumor role in CCA cells via inhibiting the activity of the Wnt/β-catenin pathway, which in turn activates the mitochondrial apoptotic pathway.

Sanguinarine Regulates Tumor-Associated Macrophages to Prevent Lung Cancer Angiogenesis Through the WNT/β-Catenin Pathway

Tumor-associated macrophage (TAM)-mediated angiogenesis in the tumor microenvironment is a prerequisite for lung cancer growth and metastasis. Therefore, targeting TAMs, which block angiogenesis, is expected to be a breakthrough in controlling the growth and metastasis of lung cancer. In this study, we found that Sanguinarine (Sang) inhibits tumor growth and tumor angiogenesis of subcutaneously transplanted tumors in Lewis lung cancer mice. Furthermore, Sanguinarine inhibited the proliferation, migration, and lumen formation of HUVECs and the expression of CD31 and VEGF by regulating the polarization of M2 macrophages in vitro. However, the inhibitory effect of Sanguinarine on angiogenesis remained in vivo despite the clearance of macrophages using small molecule drugs. Further high-throughput sequencing suggested that WNT/β-Catenin signaling might represent the underlying mechanism of the beneficial effects of Sanguinarine. Finally, the β-Catenin activator SKL2001 antagonized the effect of Sanguinarine, indicating that Sanguinarine can regulate M2-mediated angiogenesis through the WNT/β-Catenin pathway. In conclusion, this study presents the first findings that Sanguinarine can function as a novel regulator of the WNT/β-Catenin pathway to modulate the M2 macrophage polarization and inhibit angiogenesis, which has potential application value in immunotherapy and antiangiogenic therapy for lung cancer.

Inhibition of ClC-5 suppresses proliferation and induces apoptosis in cholangiocarcinoma cells through the Wnt/β-catenin signaling pathway

Chloride channel-5 (ClC-5), an important branch of the ClC family, is involved in the regulation of the proliferation and cell-fate of a variety of cells, including tumor cells. However, its function in cholangiocarcinoma (CCA) cells remains enigmatic. Here, we discovered that ClC-5 was up-regulated in CCA tissues and CCA cell lines, while ClC-5 silencing inhibited CCA cell proliferation and induced apoptosis. Further mechanism studies revealed that ClC-5 inhibition could inhibit Wnt/β-catenin signaling activity and further activate the mitochondria apoptotic pathway in CCA cells. Furthermore, rescuing Wnt/β-catenin signaling activation eliminated the anti-tumor function of ClC-5 knockdown. Together, our research findings illustrated that ClC-5 inhibition plays an anti-tumor role in CCA cells via inhibiting the activity of the Wnt/β-catenin pathway, which in turn activates the mitochondrial apoptotic pathway. [BMB Reports 2022; 55(6): 299-304].

LncRNA NEAT1 stabilized Wnt3a via U2AF2 and activated Wnt/β-catenin pathway to alleviate ischemia stroke induced injury

BACKGROUND

Ischaemic stroke is the leading cause of mortality and disability in the world. LncRNA NEAT1 has been shown to play an important role in ischaemic injury, but the molecular mechanism remains unclear.

METHODS

qRT-PCR was used to determine the expression of lncRNA NEAT1 in OGD/R-induced BV-2 cells. Cell viability was assessed by an MTT assay, and cell apoptosis was assessed by flow cytometry. The expression of related proteins was evaluated by Western blotting and ELISA. The interactions among lncRNA NEAT1, U2AF2 and Wnt3a mRNA was demonstrated by RIP and RNA pulldown assays. XAV-939 was used as an inhibitor of the Wnt/β-catenin pathway.

RESULTS

LncRNA NEAT1 was found to be downregulated in OGD/R-induced BV-2 cells. Overexpression of lncRNA NEAT1 protected BV-2 cells against OGD/R-induced injury. LncRNA NEAT1 enhanced the stability of Wnt3a mRNA via U2AF2. Knockdown of Wnt3a or blockade of the Wnt/β-catenin pathway rescued the effect of lncRNA NEAT1.

CONCLUSIONS

LncRNA NEAT1 protected cells against OGD/R-induced apoptosis and the inflammatory response by activating the Wnt/β-catenin pathway through upregulation of Wnt3a in a U2AF2-dependent manner. LncRNA NEAT1 could be a promising therapeutic candidate for ischaemic stroke treatment in the future.

Knockdown of GBP1 inhibits BCG-induced apoptosis in macrophage RAW 264.7 cells via p38/JNK pathway

Alveolar macrophage apoptosis induced by Mycobacterium tuberculosis (Mtb) plays a significant role in mediating the pathogenesis of tuberculosis. There is growing evidence that guanylate-binding proteins (GBPs) are associated with different pathological processes such as microbial infection. However, it remains unclear whether GBPs can regulate the apoptosis of macrophages induced by Mtb. In this study, we investigated the potential effect of GBP1 on RAW 264.7 cell apoptosis during Bacillus Calmette-Guerin (BCG) infection. The results demonstrated that BCG could induce macrophage apoptosis and GBP1 upregulation. In addition, we explored the role of GBP1 in regulating BCG-induced RAW 264.7 cell apoptosis using small interfering RNAs targeting GBP1. The results showed that knockdown of GBP1 could attenuate BCG-induced apoptosis in RAW 264.7 cells. Moreover, we found that GBP1 knockdown decreased the levels of cleaved-Caspase 3 and cleaved-PARP-1, while decreased those of cleaved-Caspase 9, BAX, Cytochrome C and APAF1. These findings imply that GBP1 knockdown can prevent BCG-induced apoptosis through an endogenous apoptosis pathway. In addition, the mitochondrial membrane potential of macrophages was significantly increased after BCG infection, and GBP1 knockdown could alleviate this phenomenon. Furthermore, downregulation of GBP1 also attenuated BCG-induced accumulation of reactive oxygen species in macrophages. Mechanistically, GBP1 suppressed the phosphorylation of the target molecules in p38/JNK pathway, thus regulating the apoptosis of BGC-infected macrophages. Collectively, these findings reveal a significant role of GBP1 in mediating cell apoptosis in macrophages infected with BCG, and the molecular mechanism underlying its suppressive effect on BCG-induced apoptosis.

Comprehensive analyses of potential key genes in active tuberculosis: A systematic review

BACKGROUND

Tuberculosis (TB) is a global health problem that brings us numerous difficulties. Diverse genetic factors play a significant role in the progress of TB disease. However, still no key genes for TB susceptibility have been reported. This study aimed to identify the key genes of TB through comprehensive bioinformatics analysis.

METHODS

The series microarray datasets from the gene expression omnibus (GEO) database were analyzed. We used the online tool GEO2R to filtrate differentially expressed genes (DEGs) between TB and health control. Database for annotation can complete gene ontology function analysis as well as Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. Protein-protein interaction (PPI) networks of DEGs were established by STRING online tool and visualized by Cytoscape software. Molecular Complex Detection can complete the analysis of modules in the PPI networks. Finally, the significant hub genes were confirmed by plug-in Genemania of Cytoscape, and verified by the verification cohort and protein test.

RESULTS

There are a total of 143 genes were confirmed as DEGs, containing 48 up-regulated genes and 50 down-regulated genes. The gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis show that upregulated DEGs were associated with cancer and phylogenetic, whereas downregulated DEGs mainly concentrate on inflammatory immunity. PPI networks show that signal transducer and activator of transcription 1 (STAT1), guanylate binding protein 5 (GBP5), 2'-5'-oligoadenylate synthetase 1 (OAS1), catenin beta 1 (CTNNB1), and guanylate binding protein 1 (GBP1) were identified as significantly different hub genes.

CONCLUSION

We conclude that these genes, including TAT1, GBP5, OAS1, CTNNB1, GBP1 are a candidate as potential core genes in TB and treatment of TB in the future.

The Role of β-Catenin in Th1 Immune Response against Tuberculosis and Profiles of Expression in Patients with Pulmonary Tuberculosis

β-Catenin is a key molecule of canonical Wnt/β-catenin pathway. Its roles and expression profiles in T cells of tuberculosis (TB) remain unclear. The aim of this study was to explore the role of β-catenin in CD4⁺ T cells and its expression characteristics in patients with pulmonary tuberculosis (PTB). In this study, CD4⁺ T cell-specific β-catenin conditional knockout mice (β-CAT-cKO mice) were aerosol infected with Mycobacteria tuberculosis (Mtb) H37R_V with wild-type mice as controls. Four weeks after infection, the mRNA expression of IFN-γ, TNF-α, and TCF-7 in the lungs of mice was measured. CD4, CD8, β-catenin, IFN-γ, and TNF-α in mononuclear cells from the lungs and spleens were measured by flow cytometry, and the pathological changes of lungs were also observed. Patients with PTB were enrolled, with blood samples collected and PBMCs isolated. The expressions of β-catenin, IFN-γ, TNF-α, and PD-1 in CD4⁺ and CD8⁺ T cells were measured by flow cytometry. Results showed a decreased frequency of and reduced IFN-γ/TNF-α mRNA expression and secretion by CD4⁺ T cells in the lungs of infected β-CAT-cKO mice compared with infected wild-type controls, and only slightly more inflammatory changes were observed in the lungs. β-catenin expressions in CD4⁺ and CD8⁺ T cells were significantly decreased in blood cells of patients with severe PTB compared with those in mild PTB. The stimulation of peripheral blood mononuclear cells (PBMCs) with lithium chloride (LiCl), a stimulant of β-catenin, resulted in the increase in CD4⁺ T cell frequency, as well as their secretion of IFN-γ and TNF-α. β-Catenin demonstrated a moderately positive correlation with PD-1 in CD4⁺ T cells. β-Catenin along with PD-1 and IFN-γ in CD4⁺ T cells had a high correlation with those in CD8⁺ T cells. In conclusion, β-catenin may be involved in the regulation of Th1 response and CD4⁺ T cell frequency in TB.

Plant-Derived Food Grade Substances (PDFGS) Active Against Respiratory Viruses: A Systematic Review of Non-clinical Studies

Human diet comprises several classes of phytochemicals some of which are potentially active against human pathogenic viruses. This study examined available evidence that identifies existing food plants or constituents of edible foods that have been reported to inhibit viral pathogenesis of the human respiratory tract. SCOPUS and PUBMED databases were searched with keywords designed to retrieve articles that investigated the effect of plant-derived food grade substances (PDFGS) on the activities of human pathogenic viruses. Eligible studies for this review were those done on viruses that infect the human respiratory tract. Forty six (46) studies met the specified inclusion criteria from the initial 5,734 hits. The selected studies investigated the effects of different PDFGS on the infectivity, proliferation and cytotoxicity of different respiratory viruses including influenza A virus (IAV), influenza B virus (IBV), Respiratory syncytial virus (RSV), human parainfluenza virus (hPIV), Human coronavirus NL63 (HCoV-NL63), and rhinovirus (RV) in cell lines and mouse models. This review reveals that PDFGS inhibits different stages of the pathological pathways of respiratory viruses including cell entry, replication, viral release and viral-induced dysregulation of cellular homeostasis and functions. These alterations eventually lead to the reduction of virus titer, viral-induced cellular damages and improved survival of host cells. Major food constituents active against respiratory viruses include flavonoids, phenolic acids, tannins, lectins, vitamin D, curcumin, and plant glycosides such as glycyrrhizin, acteoside, geniposide, and iridoid glycosides. Herbal teas such as guava tea, green and black tea, adlay tea, cistanche tea, kuding tea, licorice extracts, and edible bird nest extracts were also effective against respiratory viruses in vitro. The authors of this review recommend an increased consumption of foods rich in these PDFGS including legumes, fruits (e.g berries, citrus), tea, fatty fish and curcumin amongst human populations with high prevalence of respiratory viral infections in order to prevent, manage and/or reduce the severity of respiratory virus infections.

Impact of knockdown LincRNA-Cox2 on apoptosis of macrophage infected with Bacillus Calmette-Guérin

Mycobacterium tuberculosis (Mtb)-induced apoptosis of alveolar macrophages plays an important role in the pathogenesis of tuberculosis. Previous studies indicated that massive LncRNAs could deteriorate MTB invasion or latent infection by regulating macrophage's apoptosis. However, whether LincRNA-Cox2 is involved in apoptosis of macrophage infected with Mtb is unclear. In this study, we found Bacillus Calmette-Guerin(BCG)infection induced cell apoptosis with a increasing LincRNA-Cox2 expression in RAW264.7 cells. Furthermore, the activation of TLR signal pathway elevated the expression of lincRNA-Cox2. In this regard, we used small interfering RNA to explore the role of LincRNA-Cox2 on regulating apoptosis of RAW264.7 cells infected with BCG. The results showed that si-LincRNA-Cox2 was capable of increased the expression of apoptosis-associated proteins and accumulation of ROS in BCG-infected RAW264.7 cells. Mechanically, si-LincRNA-Cox2 facilitated BCG-induced macrophage apoptosis by activating the intrinsic apoptotic pathway as well as increased the genes expression of PERK/eIF2α/CHOP. These results provide novel insights into host-pathogen interactions and highlight the potential role of LincRNA-Cox2 in regulating apoptosis induced by BCG-infection.

Regulatory role and mechanism of the inhibition of the Mcl-1 pathway during apoptosis and polarization of H37Rv-infected macrophages

BACKGROUND

Myeloid cell leukemia-1 (Mcl-1) plays an important role in the clearance of Mycobacterium tuberculosis (MTB) infection. It has the effect of anti-apoptosis, protecting macrophages that have engulfed pathogens and preventing pathogen clearance. Meanwhile, the MAPK signaling pathway plays a significant role in regulating Mcl-1 expression during tuberculosis infection. In the case of latent infection and active infection, the apoptosis and polarization of macrophages have a great influence during MTB infection, so we discussed the effect of Mcl-1 on apoptosis and polarization. Then, further discussed its mechanism.

METHODS

An infected RAW264.7 macrophage model was established to investigate the regulatory role and mechanism of the Mcl-1 pathway inhibition during apoptosis and polarization of H37Rv infection. First, Mcl-1 protein and mRNA was identified by western blotting and Real-Time Polymerase Chain Reaction (RT-PCR). RAW264.7 macrophage apoptosis was detected by flow cytometry. RT-PCR was utilized to detect Bax, Caspase-3, Cyt-c and Bcl-2 mRNA expression. Next, Then the expression levels of inflammation factors CD86, CD206, iNOS, Fizz1, IL-6, IL-10, TNF-α, and TGF-β was detected by ELISA. SEM was used to observe macrophages phenotype. Finally, Bax, Bcl-2 and Bcl-xl the expression was detected by western blotting. Confocal microscopy was used to analyze mitochondrial membrane potential using the JC-10 kit.

RESULTS

In this study, we found that inhibiting the Mcl-1 expression signaling pathway led to infection by different virulence Mycobacterium tuberculosis, as well as changes in Mcl-1 protein and mRNA expression. Concomitantly macrophage apoptosis rate also changed, While, two phenotypic states of M1 and M2 appeared in the infected cells. We also found that the mitochondrial pathway was activated, the expression of its related genes Bax, casepase3, and Cyt-c, increased, whereas that of Bcl-2 decreased, and the mitochondrial membrane depolarization function was changed.

CONCLUSIONS

We found that Mcl-1 affected the apoptosis and polarization of macrophages infected by Mycobacterium tuberculosis, mainly M1 in the early stage and M2 in the later stage. In addition, mitochondria played a crucial role in this process.

Mycobacterial Control of Host Mitochondria: Bioenergetic and Metabolic Changes Shaping Cell Fate and Infection Outcome

Mitochondria, are undoubtedly critical organelle of a eukaryotic cell, which provide energy and offer a platform for most of the cellular signaling pathways that decide cell fate. The role of mitochondria in immune-metabolism is now emerging as a crucial process governing several pathological states, including infection, cancer, and diabetes. Mitochondria have therefore been a vulnerable target for several bacterial and viral pathogens to control host machinery for their survival, replication, and dissemination. Mycobacterium tuberculosis, a highly successful human pathogen, persists inside alveolar macrophages at the primary infection site, applying several strategies to circumvent macrophage defenses, including control of host mitochondria. The infection perse and specific mycobacterial factors that enter the host mitochondrial milieu perturb mitochondrial dynamics and function by disturbing mitochondrial membrane potential, shifting bioenergetics parameters such as ATP and ROS, orienting the host cell fate and thereby infection outcome. In the present review, we attempt to integrate the available information and emerging dogmas to get a holistic view of Mycobacterium tuberculosis infection vis-a-vis mycobacterial factors that target host mitochondria and changes therein in terms of morphology, dynamics, proteomic, and bioenergetic alterations that lead to a differential cell fate and immune response determining the disease outcome. We also discuss critical host factors and processes that are overturned by Mycobacterium tuberculosis, such as cAMP-mediated signaling, redox homeostasis, and lipid droplet formation. Further, we also present alternate dogmas as well as the gaps and limitations in understanding some of the present research areas, which can be further explored by understanding some critical processes during Mycobacterium tuberculosis infection and the reasons thereof. Toward the end, we propose to have a set of guidelines for pursuing investigations to maintain uniformity in terms of early and late phase, MOI of infection, infection duration and incubation periods, the strain of mycobacteria, passage numbers, and so on, which all work as probable variables toward different readouts. Such a setup would, therefore, help in the smooth integration of information across laboratories toward a better understanding of the disease and possibilities of host-directed therapy.

Knockdown of fatty acid binding protein 4 exacerbates Bacillus Calmette-Guerin infection-induced RAW264.7 cell apoptosis via the endoplasmic reticulum stress pathway

Mycobacterial infection can induce alveolar macrophage apoptosis, which plays a vital role in the pathogenesis of tuberculosis. Accumulating evidence has demonstrated that fatty acid oxidation is involved in apoptosis during various pathological processes, including bacterial infection. However, whether fatty acid oxidation regulates mycobacterial infection-induced macrophage apoptosis remains unclear. Hence, the present study aimed to investigate the role of fatty acid binding protein 4 (FABP4) which is a carrier protein for fatty acids, in regulating apoptosis in RAW264.7 cells infected with Bacillus Calmette-Guerin (BCG). In our study, the impact of BCG infection on apoptosis and fatty acid oxidation in RAW264.7 cells was examined. Notably, we found that FABP4 was overexpressed during this process. Furthermore, small interfering RNAs targeting FABP4 were used to investigate the role of FABP4 in regulating apoptosis and fatty acid oxidation in BCG-infected RAW264.7 cells. The results indicated that mycobacterial infection promoted apoptosis and enhanced fatty acid oxidation in RAW264.7 cells. Moreover, FABP4 knockdown exacerbated BCG-induced apoptosis and upregulated the expression of p-PERK, p-eIF2α and chop, which are endoplasmic reticulum (ER) stress markers. In addition, FABP4 knockdown promoted fatty acid oxidation and ROS production, which result in the activation of ER stress. Our data suggested that FABP4 knockdown exacerbated BCG-induced apoptosis in RAW264.7 cells via the ER stress pathway.

DUSP5 (dual-specificity protein phosphatase 5) suppresses BCG-induced autophagy via ERK 1/2 signaling pathway

Autophagy is considered as an effective strategy for host cells to eliminate intracellular Mycobacterium tuberculosis (Mtb). Dual-specificity phosphatase 5 (DUSP5) is an endogenous phosphatase of ERK1/2, and plays an important role in host innate immune responses, its function in autophagy regulation however remains unexplored. In the present study, the function of DUSP5 in autophagy in Mycobacterium bovis Bacillus Calmette-Guerin (BCG)-infected RAW264.7 cells, a murine macrophage-like cell line, was examined by assessing the alteration of the cell morphology, expression of autophagy markers, and ERK1/2 signaling activation. The results demonstrated that the BCG infection could induce DUSP5 expression and activate ERK1/2 signaling in RAW264.7 cells; an activation of ERK1/2 signaling contributed to autophagic process in RAW264.7 cells. Moreover, DUSP5 knockdown increased the expression of autophagy-related proteins (Atgs), including LC3-II, Beclin1, Atg5 and Atg7. However, an overexpression of DUSP5 exhibited an opposite effect. Mechanistically, DUSP5 could inhibit the formation of autophagosome by suppressing the phosphorylation of signaling molecules in ERK1/2 signaling cascade. This study thus demonstrated a novel role of DUSP5 in modulating autophagy inRAW264.7 cells in response to BCG infection in particular, and autophagy macrophage to Mtb in general.

Caspase dependent apoptosis is required for anterior regeneration in Aeolosoma viride and its related gene expressions are regulated by the Wnt signaling pathway

Although apoptosis has been widely observed during the regenerative process, the mechanisms by which it is regulated and its roles in regeneration remained unclear. In this study, we introduced Aeolosoma viride, a fresh water annelid with an extraordinary regenerative ability as our model organism to study the functions and regulations of apoptotic caspases. Here we showed that major events of apoptosis were detected near the wounded area and showed spatial correlation with the expression patterns of caspase gene namely Avi-caspase X and two apoptosis regulators namely Avi-Bax and Avi-Bcl-xL. Next, we investigated how Avi-caspase X gene expression and apoptosis influence regeneration following head amputation. RNA interference of Avi-caspase X reduced the amounts of apoptotic cells, as well as the percentage of successful regeneration, suggesting a critical role for apoptosis in anterior regeneration of A. viride. In addition, we also discovered that the expression of apoptotic caspases was regulated by the canonical Wnt signaling pathway. Together, our study showed that caspase dependent apoptosis was critical to the anterior regeneration of A. viride, and could be regulated by the canonical Wnt signaling pathway.

Evodiamine Eliminates Colon Cancer Stem Cells via Suppressing Notch and Wnt Signaling

Evodiamine, an alkaloid contained in traditional Asian herbal medicines that have been used for hundreds years, is interesting due to its cytotoxic effects against many cancers. We examined the effect of evodiamine on the cancer stem cell (CSC) population and the bulk cultured cancer cells (BCC) of colon cancers to examine the double targeting effect. We found that three colon cancer cell lines’ BCC and CSC are effectively targeted by evodiamine. Evodiamine was able to suppress BCC proliferation and induce apoptosis of the cells captured in G2/M phase, as previously reported. However, evodiamine did not cause the accumulation of CSCs at a certain stage of the cell cycle, resulting in the elimination of stemness through an unknown mechanism. By analyzing the expression of 84 genes related to CSCs in two colon cancer cell lines’ CSC, as well as performing further informatics analyses, and quantitative RT-PCR analyses of 24 CSC genes, we found that evodiamine suppressed the expression of the genes that control key signaling pathways of CSC, namely, WNT and NOTCH signaling, to lead CSC elimination. These results suggest that evodiamine should be further developed for targeting both BCCs and CSCs in colon cancers.

Bacterial Manipulation of Wnt Signaling: A Host-Pathogen Tug-of-Wnt

The host-pathogen interface is a crucial battleground during bacterial infection in which host defenses are met with an array of bacterial counter-mechanisms whereby the invader aims to make the host environment more favorable to survival and dissemination. Interestingly, the eukaryotic Wnt signaling pathway has emerged as a key player in the host and pathogen tug-of-war. Although studied for decades as a regulator of embryogenesis, stem cell maintenance, bone formation, and organogenesis, Wnt signaling has recently been shown to control processes related to bacterial infection in the human host. Wnt signaling pathways contribute to cell cycle control, cytoskeleton reorganization during phagocytosis and cell migration, autophagy, apoptosis, and a number of inflammation-related events. Unsurprisingly, bacterial pathogens have evolved strategies to manipulate these Wnt-associated processes in order to enhance infection and survival within the human host. In this review, we examine the different ways human bacterial pathogens with distinct host cell tropisms and lifestyles exploit Wnt signaling for infection and address the potential of harnessing Wnt-related mechanisms to combat infectious disease.

The WNT Framework in Shaping Immune Cell Responses During Bacterial Infections

A large proportion of the world is inflicted with health concerns arising from infectious diseases. Moreover, there is a widespread emergence of antibiotic resistance among major infectious agents, partially stemming from their continuous dialog with the host, and their enormous capacity to remodel the latter toward a secure niche. Among the several infection-driven events, moderation of WNT signaling pathway has been identified to be strategically tuned during infections to govern host-pathogen interactions. Primarily known for its role in arbitrating early embryonic developmental events; aberrant activation of the WNT pathway has also been associated with immunological consequences during diverse patho-physiological conditions. Here, we review the different mechanisms by which components of WNT signaling pathways are exploited by discrete bacterial agents for their pathogenesis. Furthermore, recent advances on the cross-talk of WNT with other signaling pathways, the varied modes of WNT-mediated alteration of gene expression, and WNT-dependent post-transcriptional and post-translational regulation of the immune landscape during distinct bacterial infections would be highlighted.

Captopril attenuates TAC-induced heart failure via inhibiting Wnt3a/β-catenin and Jak2/Stat3 pathways

Captopril (Cap) as angiotensin-converting enzyme inhibitor (ACEi) is commonly used to treat hypertension and some types of congestive heart failure. However, few studies reported on whether Cap exerts a protective effect on myocardial apoptosis induced by transverse aortic constriction (TAC). This study aimed at investigating the possible mechanism of Cap on myocardial apoptosis induced by pressure overload. Results showed that Cap significantly decreased heart-to-body weight ratios (HBWR). Cap markedly improved cardiac function, and reduced inner diameter of ascending aorta (Asc Ao) in TAC mice as shown by echocardiography. Enzyme-linked immunosorbent assay (ELISA) results demonstrated that Cap treatment also markedly decreased the level of N-terminal pro-B-type natriuretic peptide (NT-proBNP), atrial natriuretic peptide (ANP), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Cardiac pathological changes and fibrosis have been improved after Cap treatment as shown by hematoxylin-eosin (H&E) staining and Masson's trichrome staining. Moreover, Terminal deoxynucleotidyl transferase-mediated dexoxyuridine triphosphate nick-end labeling (TUNEL) staining result indicated Cap treatment also significantly inhibited cardiac apoptosis. Western Blot results showed that Cap obviously decreased the expression of cleaved capase-3, Bax, phosphorylated Jak2 (p-Jak2), phosphorylated Stat3 (p-Stat3), Wnt3a and β-catenin proteins, as well as increased Bcl-2 expression. In conclusion, Cap showed a protective effect on TAC-induced cardiac apoptosis, which could be attributed to the inhibition of Wnt3a/β-catenin signaling pathway. Cap also attenuated myocardial hypertrophy induced by TAC via suppression of Jak2/Stat3 pathway.

A role for Wnt/β-catenin signalling in suppressing Bacillus Calmette-Guerin-induced macrophage autophagy

Mycobacterium tuberculosis (Mtb)-induced autophagy of alveolar macrophages has been confirmed to play a central role in the pathogenesis of tuberculosis. Growing evidence indicates that excessive or uncontrolled autophagic activity, which results in type II programmed cell death, can be regulated by many factors, including Wnt/β-catenin signalling. Wnt/β-catenin signalling has been demonstrated to be involved in multiple diseases through the regulation of autophagy; however, its exact role in regulating autophagy induced by Mtb remains unclear. Accordingly, this study examined the function of the Wnt/β-catenin signalling pathway in regulating Mycobacterium bovis Bacillus Calmette-Guerin (BCG)-induced autophagy in RAW264.7 macrophage cell line. In the present study, we found that BCG induced the autophagy of RAW264.7 cells in a time- and dose-dependent manner along with an accumulation of LC3 (Microtubule-associated protein 1 light chain 3) protein. Intriguingly, Wnt3a, a Wnt/β-catenin signalling ligand, significantly inhibited autophagy, with decreased autophagy rates and autophagic flux. An immunoblot analysis further revealed that Wnt/β-catenin signalling was capable of inhibiting the expression of the LC3 and autophagy-associated gene (Atg) cascade proteins in BCG-infected cells. Mechanistically, Wnt/β-catenin signalling may inhibit autophagy in BCG-infected macrophages by activating mTOR-dependent pathways. Our findings reveal the mechanisms of Wnt/β-catenin signalling regulates cellular autophagy induced by Mtb and provide novel insights into physiological and immune control of tuberculosis by modulating autophagy processes.

TLR-4/microRNA-125a/NF-κB signaling modulates the immune response to Mycobacterium tuberculosis infection

Tuberculosis (TB), caused by Mycobacterium tuberculosis, could lead to kinds of clinical disorders and remains a leading global health problem, resulting in great morbidity and mortality worldwide. Previous studies have firmly demonstrated that M. tuberculosis (M.tb) has evolved to utilize different mechanisms to evade or attenuate the host immune response, such as regulation of immune-related genes by modulation of miRNAs of host or bacteria. However, the knowledge of functions of miRNAs during M.tb infection remains limited. Here, we reported that a host microRNA, miR-125a, was significantly up-regulated by M.tb infection in both RAW264.7 and THP-1cells, in a TLR4 signaling-dependent manner. Subsequently, our results demonstrated that miR-125a was a negative regulator of NF-kB pathway by directly targeting TRAF6, resulting in the suppression of cytokines, attenuation of immune response and promotion of M.tb survival. Taken together, our findings provide a novel detailed molecular mechanism in which miR-125a was enhanced to inhibit inflammatory cytokines secretion and attenuate the immune response during M.tb infection in RAW264.7 and THP-1 cells, and suggest an intrinsic a promising anti-M.tb therapeutic target.

β-catenin decreases acquired TRAIL resistance in non-small-cell lung cancer cells by regulating the redistribution of death receptors

Tumor necrosis factor‑related apoptosis‑inducing ligand (TRAIL) exhibits antitumor activity in various types of tumor cell and tumor‑bearing animals. However, acquired TRAIL resistance is a common issue that restricts its clinical application. Previous studies have revealed that β‑catenin is associated with TRAIL resistance in melanoma and colorectal tumors. In the present study, an acquired‑resistance non‑small‑cell lung cancer (NSCLC) cell line (H460‑TR) was established from parental TRAIL‑sensitive H460 cells using a gradient ascent model (8‑256 ng/ml TRAIL). Cellular FADD‑like interleukin‑1β converting enzyme inhibitory protein and Mcl‑1 were upregulated and the cell surface distribution of death receptor (DR)4 and DR5 was downregulated in H460‑TR cells compared with the parental H460 cells. The results of reverse transcription‑quantitative polymerase chain reaction and western blot analysis indicated that H460 cells expressed increased levels of β‑catenin and were more sensitive to TRAIL compared with H460‑TR cells. β‑catenin‑knockdown in H460 cells decreased their sensitivity to TRAIL, while upregulation of β‑catenin expression in H460‑TR cells increased their sensitivity to TRAIL, increased the cell surface distribution of DRs and activated caspase‑3/8. Taken together, the results of the present study suggest that β‑catenin impairs acquired TRAIL resistance in NSCLC cells by promoting the redistribution of DR4 and DR5 to the cytomembrane, and inducing TRAIL‑mediated cell apoptosis via caspase‑3/8 activation.

Effect of gap junctions on RAW264.7 macrophages infected with H37Rv

BACKGROUND

Apoptosis and inflammation have been shown to play an important role in the mechanisms involved in the pathogenesis of Mycobacterium tuberculosis (MTB) infection. When macrophages undergo apoptosis and polarization, gap junctions (GJs) may be needed to provide conditions for their functions. Connexin 43 (Cx43) and connexin 37 (Cx37) are the main connexins in macrophages that participate in the formation of GJ channels.

METHODS

An H37Rv infection RAW264.7 macrophage model was established to investigate the associate between connexins and host macrophage immune defense response after MTB infection. First, Real-time Polymerase Chian Reaction (RT-PCR) was used to detect the mRNA expression of Cx43 and Cx37. Cx43 protein expression and location was detected by western blotting and immunofluorescence. Confocal microscope was used to assay the gap junctional intercellular communication (GJIC). Then, electron microscope used to observe the morphology of macrophages. Finally, RAW264.7 macrophage apoptosis and mitochondrial membrane potential was detected by flow cytometry, and the expression of inflammation factors such as CD86, CD206, and IL-6, IL-10, TNF-α, and TGF-β were detected by Real-time PCR and enzyme-linked-immunosorbent serologic assay (ELISA).

RESULTS

H37Rv infection significantly promoted host macrophage Cx43 mRNA and protein expression (increased 1.6-fold and 0.3-fold respectively), and enhanced host macrophage GJIC. When host macrophage cell-to-cell communication induced by H37Rv infection, the apoptosis rate and inflammatory factors expression also increased.

CONCLUSIONS

The results confirm that H37Rv infection can obviously induce host macrophage Cx43 expression and enhance GJIC, which may implicated in host macrophage inflammatory reaction, to regulate the release of inflammatory factors and/or initiate apoptosis to activate host immune defense response.

Intranasal wnt3a Attenuates Neuronal Apoptosis through Frz1/PIWIL1a/FOXM1 Pathway in MCAO Rats

After ischemic stroke, apoptosis of neurons is a primary factor in determining outcome. Wnt3a is a naturally occurring protein that has been shown to have protective effects in the brain for traumatic brain injury. Although wnt3a has been investigated in the phenomena of neurogenesis, anti-apoptosis, and anti-inflammation, it has never been investigated as a therapy for stroke. We hypothesized that the potential neuroprotective agent wnt3a would reduce infarction and improve behavior following ischemic stroke by attenuating neuronal apoptosis and promoting cell survival through the Frizzled-1/PIWI1a/FOXM1 pathway in middle cerebral artery occlusion (MCAO) rats. A total of 229 Sprague Dawley rats were assigned to male, female, and 9-month-old male MCAO or sham groups followed by reperfusion 2 h after MCAO. Animals assigned to MCAO were either given wnt3a or its control. To explore the downstream signaling of wnt3a, the following interventions were given: Frizzled-1 siRNA, PIWI1a siRNA, and PIWI1a-clustered regularly interspaced short palindromic repeats, along with the appropriate controls. Post-MCAO assessments included neurobehavioral tests, infarct volume, Western blot, and immunohistochemistry. Endogenous levels of wnt3a and Frizzled-1/PIWI1a/FOXM1 were lowered after MCAO. The administration of intranasal wnt3a, 1 h after MCAO, increased PIWIL1a and FOXM1 expression through Frizzled-1, reducing brain infarction and neurological deficits at 24 and 72 h. Frizzled-1 and PIWI1a siRNAs reversed the protective effects of wnt3a after MCAO. Restoration of PIWI1a after knockdown of Frizzled-1 increased FOXM1 survival protein and reduced cleaved caspase-3 levels. In summary, wnt3a decreases neuronal apoptosis and improves neurological deficits through Frizzled-1/PIWI1a/FOXM1 pathway after MCAO in rats. Therefore, wnt3a is a novel intranasal approach to decrease apoptosis after stroke.SIGNIFICANCE STATEMENT Only 5% of patients receive recombinant tissue plasminogen activator after stroke, and few qualify for mechanical thrombectomy. No neuroprotective agents have been successfully translated to promote neuronal survival in stroke. Thus, using a clinically relevant rat model of stroke, middle cerebral artery occlusion, we explored a novel intranasal administration of wnt3a. wnt3a naturally occurs in the body and crosses the blood-brain barrier, supporting the clinically translatable approach of intranasal administration. Significant neuronal apoptosis occurs during stroke, and wnt3a shows promise due to its antiapoptotic effects. We investigated whether wnt3a mediates its poststroke effects via Frizzled-1 and the impact on its downstream signaling molecules, PIWI1a and FOXM1, in apoptosis. Elucidating the mechanism of wnt3a will identify additional pharmacological targets and further understanding of stroke.

Temporal Regulation of Natural Killer T Cell Interferon Gamma Responses by β-Catenin-Dependent and -Independent Wnt Signaling

Natural killer T (NKT) cells are prominent innate-like lymphocytes in the liver with critical roles in immune responses during infection, cancer, and autoimmunity. Interferon gamma (IFN-γ) and IL-4 are key cytokines rapidly produced by NKT cells upon recognition of glycolipid antigens presented by antigen-presenting cells (APCs). It has previously been reported that the transcriptional coactivator β-catenin regulates NKT cell differentiation and functionally biases NKT cell responses toward IL-4, at the expense of IFN-γ production. β-Catenin is not only a central effector of Wnt signaling but also contributes to other signaling networks. It is currently unknown whether Wnt ligands regulate NKT cell functions. We thus investigated how Wnt ligands and β-catenin activity shape liver NKT cell functions in vivo in response to the glycolipid antigen, α-galactosylceramide (α-GalCer) using a mouse model. Pharmacologic targeting of β-catenin activity with ICG001, as well as myeloid-specific genetic ablation of Wntless (Wls), to specifically target Wnt protein release by APCs, enhanced early IFN-γ responses. By contrast, within several hours of α-GalCer challenge, myeloid-specific Wls deficiency, as well as pharmacologic targeting of Wnt release using the small molecule inhibitor IWP-2 impaired α-GalCer-induced IFN-γ responses, independent of β-catenin activity. These data suggest that myeloid cell-derived Wnt ligands drive early Wnt/β-catenin signaling that curbs IFN-γ responses, but that, subsequently, Wnt ligands sustain IFN-γ expression independent of β-catenin activity. Our analyses in ICG001-treated mice confirmed a role for β-catenin activity in driving early IL-4 responses by liver NKT cells. However, neither pharmacologic nor genetic perturbation of Wnt production affected the IL-4 response, suggesting that IL-4 production by NKT cells in response to α-GalCer is not driven by released Wnt ligands. Collectively, these data reveal complex temporal roles of Wnt ligands and β-catenin signaling in the regulation of liver NKT cell activation, and highlight Wnt-dependent and -independent contributions of β-catenin to NKT cell functions.

Wnt/catenin β1/microRNA 183 predicts recurrence and prognosis of patients with colorectal cancer

The present study assessed the association between the Wnt/catenin β1 (CTNNB1)/microRNA (miR)183 signaling pathway and the recurrence and prognosis of colorectal cancer. The expression of Wnt, CTNNB1 and miR183 in primary colorectal cancer tissue was increased compared with that in the paracarcinoma tissue. Disease-free survival and overall survival were decreased in patients with colorectal cancer and increased miR183 expression compared with those in patients with colorectal cancer and decreased miR183 expression. The human colorectal cancer cell line HCT-116 was treated with 5 µM inhibitor of Wnt response (IWR-2) for 24 h to inhibit Wnt protein expression. Downregulating Wnt and CTNNB1 expression inhibited the viability of, and induced cell death and caspase 3 protein expression in, HCT-116 cells. The expression of BCL2 associated X protein and miR183 was increased, and cyclin D1 protein expression was suppressed, by the downregulation of Wnt and CTNNB1 expression in HCT-116 cells. Collectively, the results of the present study suggested that the Wnt/CTNNB1/miR183 signaling pathway may represent a promising biomarker for the recurrence and prognosis of colorectal cancer.

Mitigation of sepsis-induced inflammatory responses and organ injury through targeting Wnt/β-catenin signaling

The Wnt/β-catenin pathway has been involved in regulating inflammation in various infectious and inflammatory diseases. Sepsis is a life-threatening condition caused by dysregulated inflammatory response to infection with no effective therapy available. Recently elevated Wnt/β-catenin signaling has been detected in sepsis. However, its contribution to sepsis-associated inflammatory response remains to be explored. In this study, we show that inhibition of Wnt/β-catenin signaling reduces inflammation and mitigates sepsis-induced organ injury. Using in vitro LPS-stimulated RAW264.7 macrophages, we demonstrate that a small-molecule inhibitor of β-catenin responsive transcription, iCRT3, significantly reduces the LPS-induced Wnt/β-catenin activity and also inhibits TNF-α production and IκB degradation in a dose-dependent manner. Intraperitoneal administration of iCRT3 to C57BL/6 mice, subjected to cecal ligation and puncture-induced sepsis, decreases the plasma levels of proinflammatory cytokines and organ injury markers in a dose-dependent manner. The histological integrity of the lungs is improved with iCRT3 treatment, along with reduced lung collagen deposition and apoptosis. In addition, iCRT3 treatment also decreases the expression of the cytokines, neutrophil chemoattractants, as well as the MPO activity in the lungs of septic mice. Based on these findings we conclude that targeting the Wnt/β-Catenin pathway may provide a potential therapeutic approach for treatment of sepsis.

WNT ligands contribute to the immune response during septic shock and amplify endotoxemia-driven inflammation in mice

Improved understanding of the molecular mechanisms underlying dysregulated inflammatory responses in severe infection and septic shock is urgently needed to improve patient management and identify new therapeutic opportunities. The WNT signaling pathway has been implicated as a novel constituent of the immune response to infection, but its contribution to the host response in septic shock is unknown. Although individual WNT proteins have been ascribed pro- or anti-inflammatory functions, their concerted contributions to inflammation in vivo remain to be clearly defined. Here we report differential expression of multiple WNT ligands in whole blood of patients with septic shock and reveal significant correlations with inflammatory cytokines. Systemic challenge of mice with lipopolysaccharide (LPS) similarly elicited differential expression of multiple WNT ligands with correlations between WNT and cytokine expression that partially overlap with the findings in human blood. Molecular regulators of WNT expression during microbial encounter in vivo are largely unexplored. Analyses in gene-deficient mice revealed differential contributions of Toll-like receptor signaling adaptors, a positive role for tumor necrosis factor, but a negative regulatory role for interleukin (IL)-12/23p40 in the LPS-induced expression of Wnt5b, Wnt10a, Wnt10b, and Wnt11. Pharmacologic targeting of bottlenecks of the WNT network, WNT acylation and β-catenin activity, diminished IL-6, tumor necrosis factor, and IL-12/23p40 in serum of LPS-challenged mice and cultured splenocytes, whereas IL-10 production remained largely unaffected. Taken together, our data support the conclusion that the concerted action of WNT proteins during severe infection and septic shock promotes inflammation, and that this is, at least in part, mediated by WNT/β-catenin signaling.

Heme Oxygenase-1/Carbon Monoxide-regulated Mitochondrial Dynamic Equilibrium Contributes to the Attenuation of Endotoxin-induced Acute Lung Injury in Rats and in Lipopolysaccharide-activated Macrophages

BACKGROUND

Sepsis-associated acute lung injury remains the major cause of mortality in critically ill patients and is characterized by marked oxidative stress and mitochondrial dysfunction. Mitochondrial dynamics are indispensable for functional integrity. Additionally, heme oxygenase (HO)-1/carbon monoxide conferred cytoprotection against end-organ damage during endotoxic shock. Herein, we tested the hypothesis that HO-1/carbon monoxide played a critical role in maintaining the dynamic process of mitochondrial fusion/fission to mitigate lung injury in Sprague-Dawley rats or RAW 264.7 macrophages exposed to endotoxin.

METHODS

The production of reactive oxygen species, the respiratory control ratio (RCR), and the expressions of HO-1 and mitochondrial dynamic markers were determined in macrophages. Concurrently, alterations in the pathology of lung tissue, lipid peroxidation, and the expressions of the crucial dynamic proteins were detected in rats.

RESULTS

Endotoxin caused a 31% increase in reactive oxygen species and a 41% decrease in RCR levels (n = 5 per group). In parallel, the increased expression of HO-1 was observed in lipopolysaccharide-stimulated macrophages, concomitantly with excessive mitochondrial fission. Furthermore, carbon monoxide-releasing molecule-2 or hemin normalized mitochondrial dynamics, which were abrogated by zinc protoporphyrin IX. Additionally, impaired mitochondrial dynamic balance was shown in Sprague-Dawley rats that received lipopolysaccharide, accompanied by pathologic injury, elevated malondialdehyde contents, decreased manganese superoxide dismutase activities, and lowered RCR levels in rat lung mitochondria. However, the above parameters were augmented by zinc protoporphyrin IX and were in turn reversed by hemin.

CONCLUSIONS

The HO-1/carbon monoxide system modulated the imbalance of the dynamic mitochondrial fusion/fission process evoked by lipopolysaccharide and efficiently ameliorated endotoxin-induced lung injury in vivo and in vitro.

Long non-coding RNA H19 induces hippocampal neuronal apoptosis via Wnt signaling in a streptozotocin-induced rat model of diabetes mellitus

Defects in hippocampal synaptic plasticity and disorders of memory and learning are the central nervous system complications of diabetes mellitus (DM). Here, we used a streptozotocin-induced rat DM model to investigate the effects of long non-coding RNA H19 (lncRNA H19) on learning and memory and apoptosis of hippocampal neurons, and the involvement of the Wnt signaling. Our data demonstrate that lncRNA H19 is highly expressed in rats with DM. Over-expression of lncRNA H19 increased positioning navigation latency in DM rats and decreased duration of space exploration. lncRNA H19 over-expression also increased hippocampal neuronal apoptosis and expression of Wnt3, β-catenin, TCF-1, Bax, caspase-8 and caspase-3. By contrast, expression of GSK-3β and Bcl-2 was suppressed in DM rats over-expressing lncRNA H19. These results suggest that lncRNA H19 induces hippocampal neuronal apoptosis via Wnt signaling, and that inhibition of lncRNA H19 may serve as a promising novel target for the treatment of cognitive decline in patients with DM.

Activation of the Wnt Pathway by Mycobacterium tuberculosis: A Wnt-Wnt Situation

Mycobacterium tuberculosis (M. tuberculosis), an intracellular pathogenic Gram-positive bacterium, is the cause of tuberculosis (TB), a major worldwide human infectious disease. The innate immune system is the first host defense against M. tuberculosis. The recognition of this pathogen is mediated by several classes of pattern recognition receptors expressed on the host innate immune cells, including Toll-like receptors, Nod-like receptors, and C-type lectin receptors like Dectin-1, the Mannose receptor, and DC-SIGN. M. tuberculosis interaction with any of these receptors activates multiple signaling pathways among which the protein kinase C, the MAPK, and the NFκB pathways have been widely studied. These pathways have been implicated in macrophage invasion, M. tuberculosis survival, and impaired immune response, thus promoting a successful infection and disease. Interestingly, the Wnt signaling pathway, classically regarded as a pathway involved in the control of cell proliferation, migration, and differentiation in embryonic development, has recently been involved in immunoregulatory mechanisms in infectious and inflammatory diseases, such as TB, sepsis, psoriasis, rheumatoid arthritis, and atherosclerosis. In this review, we present the current knowledge supporting a role for the Wnt signaling pathway during macrophage infection by M. tuberculosis and the regulation of the immune response against M. tuberculosis. Understanding the cross talk between different signaling pathways activated by M. tuberculosis will impact on the search for new therapeutic targets to fuel the rational design of drugs aimed to restore the immunological response against M. tuberculosis.

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.

Adjunct Strategies for Tuberculosis Vaccines: Modulating Key Immune Cell Regulatory Mechanisms to Potentiate Vaccination

Tuberculosis (TB) remains a global health threat of alarming proportions, resulting in 1.5 million deaths worldwide. The only available licensed vaccine, Bacillus Calmette–Guérin, does not confer lifelong protection against active TB. To date, development of an effective vaccine against TB has proven to be elusive, and devising newer approaches for improved vaccination outcomes is an essential goal. Insights gained over the last several years have revealed multiple mechanisms of immune manipulation by Mycobacterium tuberculosis (Mtb) in infected macrophages and dendritic cells that support disease progression and block development of protective immunity. This review provides an assessment of the known immunoregulatory mechanisms altered by Mtb, and how new interventions may reverse these effects. Examples include blocking of inhibitory immune cell coreceptor checkpoints (e.g., programed death-1). Conversely, immune mechanisms that strengthen immune cell effector functions may be enhanced by interventions, including stimulatory immune cell coreceptors (e.g., OX40). Modification of the activity of key cell “immunometabolism” signaling pathway molecules, including mechanistic target of rapamycin, glycogen synthase kinase-3β, wnt/β-catenin, adenosine monophosophate-activated protein kinase, and sirtuins, related epigenetic changes, and preventing induction of immune regulatory cells (e.g., regulatory T cells, myeloid-derived suppressor cells) are powerful new approaches to improve vaccine responses. Interventions to favorably modulate these components have been studied primarily in oncology to induce efficient antitumor immune responses, often by potentiation of cancer vaccines. These agents include antibodies and a rapidly increasing number of small molecule drug classes that have contributed to the dramatic immune-based advances in treatment of cancer and other diseases. Because immune responses to malignancies and to Mtb share many similar mechanisms, studies to improve TB vaccine responses using interventions based on “immuno-oncology” are needed to guide possible repurposing. Understanding the regulation of immune cell functions appropriated by Mtb to promote the imbalance between protective and pathogenic immune responses may guide the development of innovative drug-based adjunct approaches to substantially enhance the clinical efficacy of TB vaccines.

Low Dose BCG Infection as a Model for Macrophage Activation Maintaining Cell Viability

Mycobacterium bovis BCG, the current vaccine against tuberculosis, is ingested by macrophages promoting the development of effector functions including cell death and microbicidal mechanisms. Despite accumulating reports on M. tuberculosis, mechanisms of BCG/macrophage interaction remain relatively undefined. In vivo, few bacilli are sufficient to establish a mycobacterial infection; however, in vitro studies systematically use high mycobacterium doses. In this study, we analyze macrophage/BCG interactions and microenvironment upon infection with low BCG doses and propose an in vitro model to study cell activation without affecting viability. We show that RAW macrophages infected with BCG at MOI 1 activated higher and sustained levels of proinflammatory cytokines and transcription factors while MOI 0.1 was more efficient for early stimulation of IL-1β, MCP-1, and KC. Both BCG infection doses induced iNOS and NO in a dose-dependent manner and maintained nuclear and mitochondrial structures. Microenvironment generated by MOI 1 induced macrophage proliferation but not MOI 0.1 infection. In conclusion, BCG infection at low dose is an efficient in vitro model to study macrophage/BCG interactions that maintains macrophage viability and mitochondrial structures. This represents a novel model that can be applied to BCG research fields including mycobacterial infections, cancer immunotherapy, and prevention of autoimmunity and allergies.

Immune Cell Regulatory Pathways Unexplored as Host-Directed Therapeutic Targets for Mycobacterium tuberculosis: An Opportunity to Apply Precision Medicine Innovations to Infectious Diseases

The lack of novel antimicrobial drugs in development for tuberculosis treatment has provided an impetus for the discovery of adjunctive host-directed therapies (HDTs). Several promising HDT candidates are being evaluated, but major advancement of tuberculosis HDTs will require understanding of the master or "core" cell signaling pathways that control intersecting immunologic and metabolic regulatory mechanisms, collectively described as "immunometabolism." Core regulatory pathways conserved in all eukaryotic cells include poly (ADP-ribose) polymerases (PARPs), sirtuins, AMP-activated protein kinase (AMPK), and mechanistic target of rapamycin (mTOR) signaling. Critical interactions of these signaling pathways with each other and their roles as master regulators of immunometabolic functions will be addressed, as well as how Mycobacterium tuberculosis is already known to influence various other cell signaling pathways interacting with them. Knowledge of these essential mechanisms of cell function regulation has led to breakthrough targeted treatment advances for many diseases, most prominently in oncology. Leveraging these exciting advances in precision medicine for the development of innovative next-generation HDTs may lead to entirely new paradigms for treatment and prevention of tuberculosis and other infectious diseases.

Pathway Analyses Identify Novel Variants in the WNT Signaling Pathway Associated with Tuberculosis in Chinese Population

Tuberculosis remains a global public health problem, and its immunopathogenesis is still poorly understood. In this study, 25 single nucleotide polymorphisms (SNPs) in the WNT pathway were evaluated in relation to tuberculosis risk in a Chinese Han discovery set, and 6 candidate susceptible SNPs were further validated in a Chinese Tibetan cohort. Luciferase reporter assay, RT-qPCR and Western blot were used to assess the functionality of the important WNT polymorphisms. Five polymorphisms were associated with tuberculosis susceptibility after Bonferroni correction: SFRP1 rs4736958, CTNNB1 rs9859392, rs9870255 and rs3864004 showed decreased tuberculosis risk; SFRP1 rs7832767 was related to an increased risk (OR = 1.81, 95% CI = 1.30–2.52, p = 0.010). Patients with TT genotype of rs4736958 and rs7832767 correlated with higher CRP concentrations (p = 0.003, <0.001, respectively). Functional assays revealed that mutant alleles of rs9859392 (G), rs9870255 (C) and rs3864004 (A) were associated with significantly decreased transcriptional activity, lower CTNNB1 mRNA expression and p-β-catenin level, which were consistent with their effects of decreasing TB risk. Our results provide evidences that WNT pathway polymorphisms influence tuberculosis susceptibility and host immune response to Mycobacterium tuberculosis, suggesting that these variations may serve as novel markers for identifying the risk of developing tuberculosis.

Secreted frizzled related protein 1 protects H9C2 cells from hypoxia/re-oxygenation injury by blocking the Wnt signaling pathway

Background

In animal models, secreted frizzled related protein 1 (Sfrp1) inhibition of the Wnt signaling pathway is beneficial because Sfrp1 reduces myocardial apoptosis and prevents heart failure. The mechanisms mediating the cellular survival effect of Sfrp1 has not been completely elucidated. The present study was designed to investigate the possible protective actions of Sfrp1 on cardiac muscle cells using an in vitro model of ischemia/reperfusion, and to evaluate the possible involvement of the Wnt signaling pathway.

Methods

We used a recombinant AAV9 vector to deliver the Sfrp1 gene into H9C2 rat cardiomyoblasts and adopted an in vitro model of ischemia/reperfusion. Cell vitality was measured by CKK-8 and the trypan blue exclusion assay. Western blot was used to evaluate the expression of Dvl-1, β-catenin, c-Myc, Bax, and Bcl-2. Flow cytometry analysis of cardiomyocyte apoptosis was performed.

Results

We confirmed that Sfrp1 significantly increased cell viability (assayed by trypan blue and CKK-8) and decreased apoptosis (assayed by flow cytometry analysis and the Bax/Bcl-2 ratio). These effects were partly attributable to the ability of Sfrp1 to down-regulate Wnt signaling pathway (assayed by Western blot to evaluate the expression of Dvl-1, β-catenin, and c-Myc). Indeed, reactivation of the Wnt signaling pathway activity with the specific activator, Licl, reduced Sfrp1-induced cardioprotection during hypoxia and reoxygenation.

Conclusions

The present study demonstrated that Sfrp1 directly protected H9C2 cells from hypoxia and reoxygenation-induced reperfusion injury and apoptosis through inhibition of the Wnt signaling pathway, and added new mechanistic insight regarding the cardioprotective role of Sfrp1 on ischemic damage.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-016-0240-5) contains supplementary material, which is available to authorized users.

Wnt3a suppresses Pseudomonas aeruginosa-induced inflammation and promotes bacterial killing in macrophages

Pseudomonas aeruginosa (PA) is a common Gram‑negative bacterium and can cause serious infections, including hospital‑acquired pneumonia, suppurative bacterial keratitis and acute burn wound infection. The pathogenesis of PA infections is closely associated with excessive inflammatory responses and bacterial virulence factors. Wingless‑type MMTV integration site family, member 3A (Wnt3a), an upstream mediator in the canonical Wnt signaling pathway, has been implicated as a regulator of inflammation. However, its role in PA‑induced inflammation and bacterial clearance remains unknown. In the present study, the efficacy of Wnt3a conditioned media (Wnt3a‑CM) was assessed using western blotting and immunofluorescence, which showed that β‑catenin, a downstream molecule of Wnt3a, was upregulated and translocated to the nucleus following exposure to 50% Wnt3a‑CM for 6 h. To explore the role of Wnt3a in PA‑induced inflammation, the mRNA levels of pro‑inflammatory cytokines and apoptosis in macrophages were measured using reverse transcription‑quantitative polymerase chain reaction and flow cytometry, respectively. This indicated that Wnt3a suppressed inflammation by reducing the production of pro‑inflammatory cytokines and by promoting apoptosis in macrophages. Furthermore, the mechanism of macrophage‑mediated bacterial killing was investigated, and the results indicated that Wnt3a enhanced macrophage‑mediated intracellular bacterial killing via the induction of the production of cathelicidin‑related antimicrobial peptide and β‑defensins 1. Taken together, the current study explored the role of Wnt3a in inflammation and bacterial invasion, which may provide an improved understanding of host resistance to PA infection.

Mycobacterium tuberculosis effectors interfering host apoptosis signaling

Tuberculosis remains a serious human public health concern. The coevolution between its pathogen Mycobacterium tuberculosis and human host complicated the way to prevent and cure TB. Apoptosis plays subtle role in this interaction. The pathogen endeavors to manipulate the apoptosis via diverse effectors targeting key signaling nodes. In this paper, we summarized the effectors pathogen used to subvert the apoptosis, such as LpqH, ESAT-6/CFP-10, LAMs. The interplay between different forms of cell deaths, such as apoptosis, autophagy, necrosis, is also discussed with a focus on the modes of action of effectors, and implications for better TB control.

Urinary neutrophil gelatinase-associated lipocalin is associated with heavy metal exposure in welding workers

Metals cause nephrotoxicity with acute and/or chronic exposure; however, few epidemiological studies have examined impacts of exposure to metal fumes on renal injury in welding workers. In total, 66 welding workers and 12 office workers were recruited from a shipyard located in southern Taiwan. Urine samples from each subject were collected at the beginning (baseline) and end of the work week (1-week exposure). Personal exposure to PM_2.5 was measured. The 8-h mean PM_2.5 was 50.3 μg/m³ for welding workers and 27.4 μg/m³ for office workers. iTRAQs coupled with LC-MS/MS were used to discover the pathways in response to welding PM_2.5 in the urine, suggesting that extracellular matrix (ECM)-receptor interactions are a critical mechanism. ECM-receptor interaction-related biomarkers for renal injury, kidney injury molecule (KIM)-1 and neutrophil gelatinase-associated lipocalin (NGAL), were significantly elevated in welding workers post-exposure, as well as were urinary Al, Cr, Mn, Fe, Co, and Ni levels. NGAL was more significantly associated with Al (r = 0.737, p < 0.001), Cr (r = 0.705, p < 0.001), Fe (r = 0.709, p < 0.001), and Ni (r = 0.657, p < 0.001) than was KIM-1, suggesting that NGAL may be a urinary biomarker for welding PM_2.5 exposure. Nephrotoxicity (e.g., renal tubular injury) may be an emerging concern in occupational health.

SFRP1 variations influence susceptibility and immune response to Mycobacterium tuberculosis in a Chinese Han population

OBJECTIVES

SFRP1 acts as a well-established inhibitory regulator of the Wnt signaling pathway, whose polymorphisms have been demonstrated to be associated with the risk of inflammation, infection as well as cancer. We verified the hypothesis that single nucleotide polymorphisms (SNPs) within SFRP1 gene are associated with susceptibility and clinical characteristics of tuberculosis disease in a Chinese Han population.

METHODS

Six candidate SNPs were genotyped using MassARRAY method in a case-control design (260 tuberculosis patients and 252 healthy controls). A comprehensive analysis of single locus including the genotypic, allelic frequencies and the genetic models, haplotypic construction as well as gene-gene interaction was conducted to investigate the relationships between SNPs and TB. Significant SNPs were further interrogated in relation to TB clinical features and host inflammatory status.

RESULTS

Genotype frequencies of rs4736958 and rs7832767 within SFRP1 gene were significantly different (p=0.011, p=0.008, respectively) between tuberculosis group and control group. Subjects carrying C allele for rs4736958 showed a decreased tuberculosis risk (OR=0.66, 95% CI=0.51-0.87, p=0.003), whereas individuals carrying rs7832767 T allele had a significant increased risk in tuberculosis susceptibility (OR=1.32, 95% CI=1.01-1.74, p=0.046). Genetic model analysis revealed that dominant, co-dominant and recessive models of rs4736958 were associated with decreased susceptibility to tuberculosis (p all <0.05), while the recessive and co-dominant models of rs7832767 were related to significantly increased risk for tuberculosis (p all <0.05). There was a reduced tuberculosis risk in association with the haplotype CC (representing rs3242 and rs4736958) of SFRP1 (OR=0.73, 95% CI=0.56-0.96, p=0.026). Further stratification analysis indicated that TB patients with genotype CT for rs4736958 were associated with higher CRP concentrations, and heterozygous patients (CT genotype) of rs7832767 trended towards greater ESR levels.

CONCLUSION

SNPs rs4736958 and rs7832767 of SFRP1 gene were significantly associated with tuberculosis susceptibility and might influence the expression levels of inflammatory markers of tuberculosis patients in a Chinese Han population.