WNT signaling pathway gene polymorphisms and risk of hepatic fibrosis and inflammation in HCV-infected patients

A fibroblast-dependent TGF-β1/sFRP2 noncanonical Wnt signaling axis promotes epithelial metaplasia in idiopathic pulmonary fibrosis

Reciprocal interactions between alveolar fibroblasts and epithelial cells are crucial for lung homeostasis, injury repair, and fibrogenesis, but underlying mechanisms remain unclear. To investigate, we administered the fibroblast-selective TGF-β1 signaling inhibitor epigallocatechin gallate (EGCG) to interstitial lung disease (ILD) patients undergoing diagnostic lung biopsy and conducted single-cell RNA-Seq on spare tissue. Biopsies from untreated patients showed higher fibroblast TGF-β1 signaling compared with nondisease donor or end-stage ILD tissues. In vivo, EGCG downregulated TGF-β1 signaling and several proinflammatory and stress pathways in biopsy samples. Notably, EGCG reduced fibroblast secreted frizzled-related protein 2 (sFRP2), an unrecognized TGF-β1 fibroblast target gene induced near type II alveolar epithelial cells (AEC2s) in situ. Using AEC2-fibroblast coculture organoids and precision-cut lung slices (PCLSs) from nondiseased donors, we found TGF-β1 signaling promotes a spread AEC2 KRT17+ basaloid state, whereupon sFRP2 then activates a mature cytokeratin 5+ (Krt5+) basal cell program. Wnt-receptor Frizzled 5 (Fzd5) expression and downstream calcineurin signaling were required for sFRP2-induced nuclear NFATc3 accumulation and KRT5 expression. These findings highlight stage-specific TGF-β1 signaling in ILD and the therapeutic potential of EGCG in reducing idiopathic pulmonary fibrosis-related (IPF-related) transcriptional changes and identify TGF-β1/noncanonical Wnt pathway crosstalk via sFRP2 as a mechanism for dysfunctional epithelial signaling in IPF/ILD.

A fibroblast-dependent TGFβ1/sFRP2 noncanonical Wnt signaling axis underlies epithelial metaplasia in idiopathic pulmonary fibrosis

Reciprocal interactions between alveolar fibroblasts and epithelial cells are crucial for lung homeostasis, injury repair, and fibrogenesis, but underlying mechanisms remain unclear. To investigate this, we administered the fibroblast-selective TGFβ1 signaling inhibitor, epigallocatechin gallate (EGCG), to Interstitial Lung Disease (ILD) patients undergoing diagnostic lung biopsy and conducted single-cell RNA sequencing on spare tissue. Unexposed biopsy samples showed higher fibroblast TGFβ1 signaling compared to non-disease donor or end-stage ILD tissues. In vivo, EGCG significantly downregulated TGFβ1 signaling and several pro-inflammatory and stress pathways in biopsy samples. Notably, EGCG reduced fibroblast secreted Frizzle-like Receptor Protein 2 (sFRP2), an unrecognized TGFβ1 fibroblast target gene induced near type II alveolar epithelial cells (AEC2s). In human AEC2-fibroblast coculture organoids, sFRP2 was essential for AEC2 trans-differentiation to basal cells. Precision cut lung slices (PCLS) from normal donors demonstrated that TGFβ1 promoted KRT17 expression and AEC2 morphological change, while sFRP2 was necessary for KRT5 expression in AEC2-derived basaloid cells. Wnt-receptor Frizzled 5 (Fzd5) expression and downstream calcineurin-related signaling in AEC2s were required for sFRP2-induced KRT5 expression. These findings highlight stage-specific TGFβ1 signaling in ILD, the therapeutic potential of EGCG in reducing IPF-related transcriptional changes, and identify the TGFβ1-non-canonical Wnt pathway crosstalk via sFRP2 as a novel mechanism for dysfunctional epithelial signaling in Idiopathic Pulmonary Fibrosis/ILD.

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.

Wnt signaling in liver regeneration, disease, and cancer

The liver exhibits the highest recovery rate from acute injuries. However, in chronic liver disease, the long-term loss of hepatocytes often leads to adverse consequences such as fibrosis, cirrhosis, and liver cancer. The Wnt signaling plays a pivotal role in both liver regeneration and tumorigenesis. Therefore, manipulating the Wnt signaling has become an attractive approach to treating liver disease, including cancer. Nonetheless, given the crucial roles of Wnt signaling in physiological processes, blocking Wnt signaling can also cause several adverse effects. Recent studies have identified cancer-specific regulators of Wnt signaling, which would overcome the limitation of Wnt signaling target approaches. In this review, we discussed the role of Wnt signaling in liver regeneration, precancerous lesion, and liver cancer. Furthermore, we summarized the basic and clinical approaches of Wnt signaling blockade and proposed the therapeutic prospects of cancer-specific Wnt signaling blockade for liver cancer treatment.

Functions of the WNT Signaling Network in Shaping Host Responses to Infection

It is well-established that aberrant WNT expression and signaling is associated with developmental defects, malignant transformation and carcinogenesis. More recently, WNT ligands have emerged as integral components of host responses to infection but their functions in the context of immune responses are incompletely understood. Roles in the modulation of inflammatory cytokine production, host cell intrinsic innate defense mechanisms, as well as the bridging of innate and adaptive immunity have been described. To what degree WNT responses are defined by the nature of the invading pathogen or are specific for subsets of host cells is currently not well-understood. Here we provide an overview of WNT responses during infection with phylogenetically diverse pathogens and highlight functions of WNT ligands in the host defense against infection. Detailed understanding of how the WNT network orchestrates immune cell functions will not only improve our understanding of the fundamental principles underlying complex immune response, but also help identify therapeutic opportunities or potential risks associated with the pharmacological targeting of the WNT network, as currently pursued for novel therapeutics in cancer and bone disorders.

WNT Signaling in Disease

Developmental signaling pathways control a vast array of biological processes during embryogenesis and in adult life. The WNT pathway was discovered simultaneously in cancer and development. Recent advances have expanded the role of WNT to a wide range of pathologies in humans. Here, we discuss the WNT pathway and its role in human disease and some of the advances in WNT-related treatments.

Association of genetic variations in the Wnt signaling pathway genes with myocardial infarction susceptibility in Chinese Han population

Numerous studies have implicated the Wnt pathway in the development and progression of myocardial infarction (MI); however, there are very few investigations addressing the effects of polymorphisms in the Wnt pathway genes on MI susceptibility. We investigated the possible correlation between genetic variations in Wnt pathway genes and MI risk. Three polymorphisms (rs7832767 C > T in SFRP1 gene, rs2293303 C > T in CTNNB1 gene, rs16893344 C > T in WISP1 gene) were finally selected and genotyped in 465 MI patients and 485 healthy controls, using the PCR-RFLP method. We found that the SFRP1 rs7832767 variant allele (T) was associated with a significantly increased risk of MI [TT vs. CC: adjusted odds ratio (AOR) = 3.13, 95% CI = 1.78-5.51; CT/TT vs. CC: AOR = 1.53, 95% CI = 1.12-2.08; TT vs. CC/CT: AOR = 2.87, 95% CI = 1.66-4.97)]. The significant association with MI risk was also found for the CTNNB1 rs2293303 (CT vs. CC: AOR = 3.48, 95% CI = 2.28-5.33; TT vs. CC: AOR = 7.37, 95% CI = 2.08-26.16; CT/TT vs. CC: AOR = 3.72, 95% CI = 2.46-5.62; TT vs. CC/CT: AOR = 5.52, 95% CI = 1.58-19.28), and WISP1 rs16893344 polymorphisms (CT vs. CC: AOR = 2.43, 95% CI = 1.70-3.47; TT vs. CC: AOR = 5.17, 95% CI = 1.85-14.41; CT/TT vs. CC: AOR = 2.58, 95% CI = 1.83-3.66; TT vs. CC/CT: AOR = 3.88, 95% CI = 1.41-10.64). The associations remain significant in stratified analysis by demographic and clinical characteristics of participants, with few exceptions. Our study provided the first evidence of the association between polymorphisms in the Wnt pathway genes and MI susceptibility in Chinese Han population. Epidemiological studies with larger samples and functional analyses are warranted to further verify our results.

Hepatitis C virus-induced CCL5 secretion from macrophages activates hepatic stellate cells

Hepatitis C virus (HCV)-mediated chronic liver disease is a serious health problem around the world and often causes fibrosis/cirrhosis and hepatocellular carcinoma. The mechanism of liver disease progression during HCV infection is still unclear, although inflammation is believed to be an important player in disease pathogenesis. We previously reported that macrophages including Kupffer cells exposed to HCV induce proinflammatory cytokines. These secreted cytokines may activate hepatic stellate cells (HSCs) toward fibrosis. In this study, we examined crosstalk between macrophages and HSCs following HCV infection. Primary human HSCs and immortalized HSCs (LX2 cells) were incubated with conditioned medium derived from HCV-exposed human macrophages. Expression of inflammasome and fibrosis-related genes in these cells was examined, with increased expression of inflammatory (NLR family pyrin domain containing 3, interleukins 1β and 6, and cysteine-cysteine chemokine ligand 5 [CCL5]) and profibrogenic (transforming growth factor β1, collagen type 4 alpha 1, matrix metalloproteinase 2, and alpha-smooth muscle actin) markers. Further investigation suggested that CCL5, secreted from HCV-exposed macrophages, activates inflammasome and fibrosis markers in HSCs and that neutralizing antibody to CCL5 inhibited activation.

CONCLUSION

Together, our results demonstrate that human macrophages exposed to HCV induce CCL5 secretion, which plays a significant role in hepatic inflammation and fibrosis. (Hepatology 2017;66:746-757).

Features of hepatocellular carcinoma in Hispanics differ from African Americans and non-Hispanic Whites

AIM

To compare features of hepatocellular carcinoma (HCC) in Hispanics to those of African Americans and Whites.

METHODS

Patients treated for HCC at an urban tertiary medical center from 2005 to 2011 were identified from a tumor registry. Data were collected retrospectively, including demographics, comorbidities, liver disease characteristics, tumor parameters, treatment, and survival (OS) outcomes. OS analyses were performed using Kaplan-Meier method.

RESULTS

One hundred and ninety-five patients with HCC were identified: 80.5% were male, and 22% were age 65 or older. Mean age at HCC diagnosis was 59.7 ± 9.8 years. Sixty-one point five percent of patients had Medicare or Medicaid; 4.1% were uninsured. Compared to African American (31.2%) and White (46.2%) patients, Hispanic patients (22.6%) were more likely to have diabetes (P = 0.0019), hyperlipidemia (P = 0.0001), nonalcoholic steatohepatitis (NASH) (P = 0.0021), end stage renal disease (P = 0.0057), and less likely to have hepatitis C virus (P < 0.0001) or a smoking history (P < 0.0001). Compared to African Americans, Hispanics were more likely to meet criteria for metabolic syndrome (P = 0.0491), had higher median MELD scores (P = 0.0159), ascites (P = 0.008), and encephalopathy (P = 0.0087). Hispanic patients with HCC had shorter OS than the other racial groups (P = 0.020), despite similarities in HCC parameters and treatment.

CONCLUSION

In conclusion, Hispanic patients with HCC have higher incidence of modifiable metabolic risk factors including NASH, and shorter OS than African American and White patients.

Action and function of Wnt/β-catenin signaling in the progression from chronic hepatitis C to hepatocellular carcinoma

Hepatitis C virus (HCV) infection is one of the leading causes of hepatocellular carcinoma (HCC) worldwide but the mechanistic basis as to how chronic HCV infection furthers the HCC process remains only poorly understood. Accumulating evidence indicates that HCV core and nonstructural proteins provoke activation of the Wnt/β-catenin signaling pathway, and the evidence supporting a role of Wnt/β-catenin signaling in the onset and progression of HCC is compelling. Convincing molecular explanations as to how expression of viral effectors translates into increased activity of the Wnt/β-catenin signaling machinery are still largely lacking, hampering the design of rational strategies aimed at preventing HCC. Furthermore, how such increased signaling is especially associated with HCC oncogenesis in the context of HCV infection remains obscure as well. Here we review the body of contemporary biomedical knowledge on the role of the Wnt/β-catenin pathway in the progression from chronic hepatitis C to cirrhosis and HCC and explore potential hypotheses as to the mechanisms involved.

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.

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.

Paradoxical increase of plasma vitamin B12 and folates with disease severity in anorexia nervosa

OBJECTIVE

Anorexia nervosa (AN) is a complex disorder involving severe psychological manifestations and multiple organ damage, including liver dysfunction. The primary aim of this study consisted in assessing plasma levels of vitamin B12 and folates with respect to liver function enzymes considering the liver-storage properties of this vitamin.

METHOD

We recruited 70 restrictive type AN adolescents and the severity of psychopathological traits was assessed using EDI-3 scale. Plasma levels of vitamin B12 , folates, transaminases (AST, ALT), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (ALP) and cholinesterase (CHE) were determined.

RESULTS

About 38.5% of patients displayed vitamin B12 values (H-B12) above the upper range of normal reference; 4.3% of patients had increased values of folates; 20 and 11.4% of patients displayed ALT and AST values above reference limits; none had GGT values above normal range. Albeit low CHE and ALP values were found in 55 and 20% of patients, respectively, a linear correlation with both transaminases was present only for vitamin B12 and folates; furthermore, H-B12 patients had both higher AST and ALT values. EDI- 3 subscores significantly correlated with vitamin B12 and folates plasma values and H-B12 patients displayed EDI-3 higher values.

DISCUSSION

These data suggest that plasma levels of vitamin B12 might be an early marker of liver dysfunction, possibly also related to more severe psychopathological aspects. The identification of patients with higher fasting plasma vitamin B12 levels could therefore lead to earlier and more careful refeeding interventions. Further studies will clarify the potential role of this vitamin in AN clinical practice.

Association of genetic variants in Wnt signaling pathway with tuberculosis in Chinese Han population

Compelling studies have implicated that the Wnt signaling pathway plays an important role in the development and progression of tuberculosis, however, there is little literature addressing the role of polymorphisms in Wnt pathway on tuberculosis. We took a pathway based candidate gene approach to investigate the possible correlation between genetic variants in Wnt pathway and tuberculosis. Three single nucleotide polymorphisms (SNPs) in Wnt pathway (rs4135385 in CTNNB1 gene, rs7832767 in SFRP1 gene, and rs11079571 in AXIN2 gene) were genotyped in 422 Chinese Han tuberculosis patients and 402 frequency matched (age, gender, and ethnicity) controls using high-resolution melting analysis. The genotype and allelic frequencies of rs4135385 and rs7832767 were significantly different among patients and controls. The dominant model of rs4135385 was significantly associated with an increased risk of tuberculosis (AG/GG versus AA: OR = 1.49, 95% CI = 1.06–2.09, p = 0.019). The recessive model of rs7832767 posed a significant higher risk for tuberculosis (TT versus TC/CC, OR = 2.70, 95% CI = 1.41–5.18, p = 0.002). These SNPs were further evaluated whether they were correlated with the site of tuberculosis and the level of inflammatory markers. Rs7832767 was significantly associated with the level of CRP (p = 0.014), and the patients carrying T allele might present with elevated CRP values (OR = 1.90, 95% CI = 1.21–2.96, p = 0.005). Our study provided the first evidence that rs4135385 and rs7832767 were associated with tuberculosis risk, and genetic variants in Wnt signaling pathway might participate in genetic susceptibility to tuberculosis in Chinese Han population. Further epidemiological and functional studies in larger populations are warranted to verify our results.