sTRAIL levels and TRAIL gene polymorphisms in Chinese patients with fatty liver disease

Role of genetic variants and DNA methylation of lipid metabolism-related genes in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD), is one of the most common chronic liver diseases, which encompasses a spectrum of diseases, from metabolic dysfunction-associated steatotic liver (MASL) to metabolic dysfunction-associated steatohepatitis (MASH), and may ultimately progress to MASH-related cirrhosis and hepatocellular carcinoma (HCC). MASLD is a complex disease that is influenced by genetic and environmental factors. Dysregulation of hepatic lipid metabolism plays a crucial role in the development and progression of MASLD. Therefore, the focus of this review is to discuss the links between the genetic variants and DNA methylation of lipid metabolism-related genes and MASLD pathogenesis. We first summarize the interplay between MASLD and the disturbance of hepatic lipid metabolism. Next, we focus on reviewing the role of hepatic lipid related gene loci in the onset and progression of MASLD. We summarize the existing literature around the single nucleotide polymorphisms (SNPs) associated with MASLD identified by genome-wide association studies (GWAS) and candidate gene analyses. Moreover, based on recent evidence from human and animal studies, we further discussed the regulatory function and associated mechanisms of changes in DNA methylation levels in the occurrence and progression of MASLD, with a particular emphasis on its regulatory role of lipid metabolism-related genes in MASLD and MASH. Furthermore, we review the alterations of hepatic DNA and blood DNA methylation levels associated with lipid metabolism-related genes in MASLD and MASH patients. Finally, we introduce potential value of the genetic variants and DNA methylation profiles of lipid metabolism-related genes in developing novel prognostic biomarkers and therapeutic targets for MASLD, intending to provide references for the future studies of MASLD.

Exploring the dynamic role of circulating soluble tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as a diagnostic and prognostic marker; a review

Tumor necrosis factor (TNF) related apoptosis-inducing ligand (TRAIL) is a TNF superfamily cytokine primarily acknowledged for its ability to selectively induce apoptosis in cancer cells. Beyond its antitumor effects, recent literature emphasizes the pleiotropic functions of TRAIL in physiological states and acute/chronic non-malignant diseases indicating its potential to be a breakthrough in diagnostics. This review explores the current understanding of the dynamic role of circulating soluble TRAIL (sTRAIL) and its potential as both a diagnostic and prognostic marker. Multiple in vitro, in vivo, and clinical studies in a wide range of neoplastic and non-neoplastic diseases including infectious diseases have been carried out to explore the potential role of sTRAIL in disease pathogenesis and as well as the possibilities of using it as a diagnostic and prognostic marker. The expression of sTRAIL seems to be context-dependent suggesting further research, particularly towards establishing disease-specific cutoff values. However, the lack of standardization in the serum sTRAIL estimation and the absence of reference intervals remain significant barriers to its clinical application. Addressing these challenges is essential for using circulating sTRAIL as an accurate diagnostic and prognostic marker in clinical practice.

The Impact of TRAIL (C1595T and G1525A) and DR4 (rs20576) Gene Polymorphisms on Systemic Lupus Erythematosus

Apoptosis dysregulation is a distinct hallmark of several disorders like systemic lupus erythematosus (SLE). In fact, SLE has two special features for apoptosis: irregular apoptosis and decline in clearing of apoptotic bodies. Tumor Necrosis Factor (TNF)-Related Apoptosis-Inducing Ligand (TRAIL) is a death ligand that causes to apoptosis via attaching to its receptors such as death receptor-4 (DR4). The present study aimed to evaluate the effects of TRAIL G1525A and C1595T and DR4 A683C (rs20576) gene polymorphisms on SLE development. 160 SLE patients and 160 healthy individuals as the control group participated in the study. Genotype analysis was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). With regard to TRAIL (C1595T) polymorphism, the frequency of CT genotype was significantly higher in the case group than the control with 3-fold increase in SLE development risk (P = 0.0001). Furthermore, the frequency of the TT genotype also was higher in the case group than the control group with 3.2-fold increase in SLE development risk. The allelic distribution analysis defined the T allele as a risk factor for SLE development (P = 0.0001). The frequency of AA genotype and allele A of TRAIL (G1525A) polymorphism also was statistically higher in the case group than the control group (P = 0.0001). There was no significant association between DR4 rs20576 polymorphism and SLE development. TRAIL C1595T and G1525A gene polymorphisms are suggested as the risk factors for SLE development, although the results showed no association between DR4 rs20576 polymorphism and SLE.

Effect of trail C1595T variant and gene expression on the pathogenesis of non-small cell lung cancer

It is known that disorders in apoptosis function play an important role in the pathogenesis of many types of cancer, including lung cancer. Tumor necrosis factor related apoptosis inducing ligand (TRAIL), a type II transmembrane protein, is a death ligand capable of inducing apoptosis by activating distinctive death receptor. Our purpose in this study is to investigate the gene polymorphisms in TRAIL molecular pathway and TRAIL gene expression levels in non-small cell lung cancer (NSCLC) patients in terms of pathogenesis and prognosis of the disease. In this study, TRAIL C1595T polymorphism was genotyped using polymerase chain reaction-restriction fragment length polymorphism analysis in 158 patients with NSCLC and 98 healthy individuals. Surgically resected tissues were examined and classified histopathologically. In addition, TRAIL gene expression levels in tumor tissue and tumor surrounding tissue samples of 48 patients with NSCLC were determined using real-time polymerase chain reaction. TRAIL gene expression levels of NSCLC patients were detected significantly 28.8 fold decrease in the tumor tissue group compared to the control group (p=0.026). When patients were compared to tumor stage, expression of TRAIL gene in advanced tumor stage was found to be significantly 7.86 fold higher than early tumor stage [p=0.028]. No significant relationship was found between NSCLC predisposition and prognostic parameters of NSCLC with TRAIL genotypes, but the frequency of TRAIL gene 1595 CT genotype was observed to be lower in the patients compared to the other genotypes, and the difference was found to be very close to statistical significance (p=0.07). It can be suggested that TRAIL may play an important role in the development of NSCLC and may be an effective prognostic factor in tumor progression.: It is known that disorders in apoptosis function play an important role in the pathogenesis of many types of cancer, including lung cancer. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a type II transmembrane protein, is a death ligand capable of inducing apoptosis by activating distinctive death receptor. Our purpose in this study is to investigate the gene polymorphisms in TRAIL molecular pathway and TRAIL gene expression levels in non-small cell lung cancer (NSCLC) patients in terms of pathogenesis and prognosis of the disease.

Insight into the role of TRAIL in liver diseases

TNF-related apoptosis inducing ligand (TRAIL) is a potential antitumor protein known for its ability to selectively eliminate various types of tumor cells without exerting toxic effects in normal cells and tissues. TRAIL has recently been suggested as a potential therapeutic target in hepatocellular carcinoma (HCC) because it promotes apoptosis in cancer cells. Furthermore, studies on the role of TRAIL in liver injury have reported that TRAIL plays an essential role in viral hepatitis, fatty liver diseases, etc. However, several contradictory and confounding effects of TRAIL in these liver diseases have not been fully elucidated or placed into perspective. Hence, this review summarizes recent progress in studies on TRAIL, including its role in apoptotic signaling, potential therapeutic applications of TRAIL in HCC, hepatitis virus infection, and liver fibrosis and cirrhosis.

Genetic and Epigenetic Culprits in the Pathogenesis of Nonalcoholic Fatty Liver Disease

Nonalcoholic Fatty Liver Disease (NAFLD) constitutes a wide spectrum of liver pathology with hepatic steatosis at the core of this pathogenesis. Variations of certain genetic components have demonstrated increased susceptibility for hepatic steatosis. Therefore, these inciting variants must be further characterized in order to ultimately provide effective, targeted therapies for NAFLD and will be the focus of this review. Several genetic variants revealed an association with NAFLD through Genome-wide Association Study, meta-analyses, and retrospective case-control studies. PNPLA3 rs738409 and TM6SF2 rs58542926 are the two genetic variants providing the strongest evidence for association with NAFLD. However, it remains to be determined if these genetic variants serve as the primary culprit which induces the pathogenesis of NAFLD. Prospective and intervention studies are urgently needed to firmly establish a cause-and-effect relationship between the presence of certain genetic variants and risk of NAFLD development and progression.

Association Between C1q, TRAIL, and Tim-1 Gene Polymorphisms and Systemic Lupus Erythematosus

AIM

The present study was designed to examine the relationship between gene polymorphisms of C1q, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), T cell immunoglobulin mucin (Tim-1), and systemic lupus erythematosus (SLE).

MATERIALS AND METHODS

A total of 245 SLE patients were selected from February 2012 to August 2016, along with 245 healthy donors as the control group. Genomic DNA was extracted from peripheral blood samples from all subjects followed by mutational analyses. Gene polymorphisms of the C1q gene (rs292001, rs631090, rs294223 loci); the TRAIL gene (1525A/G, 1588A/G, 1595T/C locus); and the Tim-1 gene were detected by sequencing after polymerase chain reaction amplification. The concentration of anti-C1q antibody and the protein levels of sTRAIL/Tim-1 in serum of all subjects were measured by enzyme-linked immunosorbent assay.

RESULTS

As for the C1q gene, the frequency of the T allele at the rs631090 locus in the study group was lower than that in the controls, and the frequency of the C allele was higher in the study group than in the healthy donors. The frequency of the G allele at the 1525A/G locus of TRAIL gene in the study group was significantly higher than those in the control group. The frequency of the G allele at -1454G/A of Tim-1 was dramatically higher in the study group than in the control group. Anti-C1q antibody concentrations of subjects carrying CC and CT genotype at the rs631090 locus were statistically higher than TT genotype carriers. The sTRAIL protein level of the TRAIL 1525A/G GG genotype carriers was significantly higher than that of GA and AA genotype carriers, as well as CC genotype carriers at 1595T/C site compared with CT/TT genotype carriers. GG genotype carriers at -1454G/A had higher Tim-1 expression levels than GA/AA genotype carriers.

CONCLUSION

The C allele at the rs631090 locus of C1q, the G allele at 1525A/G site of TRAIL, and the G allele of Tim-1 at -1454G/A site are susceptibility variants associated with SLE.

Non-alcoholic fatty liver disease, vascular inflammation and insulin resistance are exacerbated by TRAIL deletion in mice

Non-alcoholic fatty liver disease (NAFLD) incorporates steatosis, non-alcoholic steato-hepatitis (NASH) and liver cirrhosis, associating with diabetes and cardiovascular disease (CVD). TNF-related apoptosis-inducing ligand (TRAIL) is protective of CVD. We aimed to determine whether TRAIL protects against insulin resistance, NAFLD and vascular injury. Twelve-week high fat diet (HFD)-fed Trail^−/− mice had increased plasma cholesterol, insulin and glucose compared to wildtype. Insulin tolerance was impaired with TRAIL-deletion, with reduced p-Akt, GLUT4 expression and glucose uptake in skeletal muscle. Hepatic triglyceride content, inflammation and fibrosis were increased with TRAIL-deletion, with elevated expression of genes regulating lipogenesis and gluconeogenesis. Moreover, Trail^−/− mice exhibited reduced aortic vasorelaxation, impaired insulin signaling, and >20-fold increased mRNA expression for IL-1β, IL-6, and TNF-α. In vitro, palmitate treatment of hepatocytes increased lipid accumulation, inflammation and fibrosis, with TRAIL mRNA significantly reduced. TRAIL administration inhibited palmitate-induced hepatocyte lipid uptake. Finally, patients with NASH had significantly reduced plasma TRAIL compared to control, simple steatosis or obese individuals. These findings suggest that TRAIL protects against insulin resistance, NAFLD and vascular inflammation. Increasing TRAIL levels may be an attractive therapeutic strategy, to reduce features of diabetes, as well as liver and vascular injury, so commonly observed in individuals with NAFLD.

A -1573T>C SNP within the human TRAIL promoter determines TRAIL expression and HCC tumor progression

The cytokine tumor necrosis factor (TNF)‐related apoptosis‐inducing ligand (TRAIL) induces apoptosis in liver cancer cells but not in normal liver cells. Therefore, TRAIL got credited to play a role in hepatocellular carcinoma (HCC) development and progression. Impaired expression of TRAIL in HCC cells and sequence variations in the TRAIL promoter may facilitate development, growth, and spread . The TRAIL promoter was sequenced from liver tissue of 93 patients undergoing partial liver resection (PRT) or liver transplantation (LT) for HCC. TRAIL mRNA expression was investigated by quantitative real‐time PCR. A variant ‐1573T>C (single‐nucleotide polymorphism; C, cytosine) SNP was characterized by electron mobility shift assay and supershift assays. Functionality of the ‐1573T>C SNP was analyzed in reporter gene assays and cell migration assays. In approximately 30% of HCC samples, a loss‐of‐function shift of the binding pattern due to a ‐1573T>C SNP was found within the human TRAIL promoter. Correlation analysis revealed significantly lower TRAIL expression in HCC samples with the ‐1573C sequence (P ≤ 0.05). Reporter gene assays revealed significantly reduced inducibility of the TRAIL promoter due to the ‐1573C sequence. The variant ‐1573C sequence impaired not only binding of transcription factors but also expression of TRAIL. Interestingly, this impairment resulted in enhanced migration activity and colony formation of the liver tumor cells. Our findings suggest that loss of function of the human TRAIL promoter due to the ‐1573T>C SNP leads to reduced expression and impaired inducibility of TRAIL, with the consequence of enhanced growth and migration of tumor cells, ultimately resulting in the progression of the HCC.

Genetic and epigenetic mechanisms of NASH

Along with the obesity epidemic, the prevalence of nonalcoholic fatty liver disease (NAFLD) has increased exponentially. The histological disease spectrum of NAFLD ranges from bland fatty liver (hepatic steatosis), to the concomitant presence of inflammation and ballooning which defines nonalcoholic steatohepatitis (NASH). The latter can progress in a subset to fibrosis, leading ultimately to cirrhosis and hepatocellular carcinoma. The past decade has seen tremendous advances in our understanding of the genetic and epigenetic bases of NAFLD, mainly through the application of high end technology platforms including genome-wide association studies (GWAS). These have helped to define common gene variants (minor allele frequency >5 %) that contribute to the NAFLD phenotype. Looking to the future, these discoveries are expected to lead to improved diagnostics, the personalization of medicine, and a better understanding of the pathophysiological underpinnings that drive the transition from NAFLD to steatohepatitis and fibrosis, leading to the identification of novel therapeutic targets. In this review, we summarize data on the current state of knowledge with regard to the genetic and epigenetic mechanisms for the development of NASH.

Soluble TRAIL Concentration in Serum Is Elevated in People with Hypercholesterolemia

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a multi-functional cytokine, which is involved in the pathophysiological processes of cardiovascular and metabolic diseases. Previously, we demonstrated that TRAIL stimulated lipid uptake and foam cell formation in macrophages in vitro. Several clinical studies have suggested that the serum concentration of TRAIL may be increased in humans with elevated blood cholesterol; however, the current data appear to be inconclusive in this regard. In the present study, we examined the relationships between the serum TRAIL concentration and cholesterol levels in 352 generally healthy subjects undergoing the routine annual health check. We showed that there were significant correlations between TRAIL concentration and levels of total and low-density lipoprotein cholesterols. The level of TRAIL was significantly elevated in subjects with hypercholesterolemia, although this relationship might be also associated with changes of other metabolic factors. Moreover, we showed that the level of blood cholesterol was significantly higher in subjects in the upper quartile of serum TRAIL. In conclusion, our data demonstrate that the serum TRAIL concentration is elevated in people with hypercholesterolemia.

Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand Gene Polymorphisms and Hepatitis B Virus Infection

Background:

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is an apoptotic molecule with a key role in the apoptosis of tumors and virus-infected cells. The association of 1525G/A and 1595C/T polymorphisms in the region of 3’ UTR on the TRAIL gene has been shown in many cancers and diseases. Polymorphism at the positions of 1525G/A and 1595C/T might influence the clearance of hepatitis B virus (HBV).

Objectives:

This study was carried out to determine the role of the TRAIL gene polymorphisms in clinical outcome of HBV infection.

Patients and Methods:

Polymerase chain reaction-based restriction fragment length polymorphism (PCR–RFLP) was applied to genotype TRAIL polymorphisms at positions 1525G/A and 1595C/T. To evaluate the TRAIL gene polymorphism in the 3’ UTR region at position 1525G/A and 1595C/T, 147 patients with HBV infection were divided into three different groups of chronic hepatitis (n = 52), cirrhosis (n = 33), and carrier (n = 62) and there was a group of 101 healthy controls.

Results:

Our data showed that genotypes 1525G/A and 1595C/T were in complete linkage disequilibrium and the genotype frequencies at the two positions were the same. No significant differences in frequencies of genotype and alleles at positions 1525G/A and 1595C/T were observed between all the three groups (P value > 0.05).

Conclusions:

According to our result, 1525G/A and 1595C/T were in strong linkage disequilibrium and the polymorphisms of the TRAIL gene in the 3’ UTR region were not associated with the outcome of HBV infection.

Genetic background in nonalcoholic fatty liver disease: A comprehensive review

In the Western world, nonalcoholic fatty liver disease (NAFLD) is considered as one of the most significant liver diseases of the twenty-first century. Its development is certainly driven by environmental factors, but it is also regulated by genetic background. The role of heritability has been widely demonstrated by several epidemiological, familial, and twin studies and case series, and likely reflects the wide inter-individual and inter-ethnic genetic variability in systemic metabolism and wound healing response processes. Consistent with this idea, genome-wide association studies have clearly identified Patatin-like phosholipase domain-containing 3 gene variant I148M as a major player in the development and progression of NAFLD. More recently, the transmembrane 6 superfamily member 2 E167K variant emerged as a relevant contributor in both NAFLD pathogenesis and cardiovascular outcomes. Furthermore, numerous case-control studies have been performed to elucidate the potential role of candidate genes in the pathogenesis and progression of fatty liver, although findings are sometimes contradictory. Accordingly, we performed a comprehensive literature search and review on the role of genetics in NAFLD. We emphasize the strengths and weaknesses of the available literature and outline the putative role of each genetic variant in influencing susceptibility and/or progression of the disease.

Genetic variants in the tumor necrosis factor-related apoptosis-inducing ligand and death receptor genes contribute to susceptibility to bladder cancer

AIM

The aim of this study was to evaluate the role of polymorphisms of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and death receptor (DR4) genes in bladder cancer susceptibility in a Turkish population.

MATERIALS AND METHODS

The study group included 91 bladder cancer patients, while the control group comprised 139 individuals with no evidence of malignancy. Gene polymorphisms of TRAIL C1595T (rs1131580) and DR4 C626G (rs4871857) were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis.

RESULTS

The frequency of the TRAIL 1595 TT genotype was significantly lower in patients with bladder cancer compared to controls (p<0.001; odds ratios [OR]=0.143; 95% confidence interval [CI]=0.045-0.454). A significantly increased risk for developing bladder cancer was found for the group bearing a C allele for TRAIL C1595T polymorphism (p<0.001; OR=1.256; 95% CI=1.138-1.386). The observed genotype and allele frequencies of DR4 626 C/G in all groups were in agreement with the Hardy-Weinberg equilibrium (p=0.540). However, the frequency of DR4 GG genotype was found to be 2.1-fold increased in the bladder cancer patients with high-grade tumor, when compared to those having low-grade tumor (p=0.036). Additionally, combined genotype analysis showed that the frequency of TRAILCT-DR4GG was significantly higher in patients with bladder cancer in comparison with those of controls (p=0.037; OR=2.240; 95% CI=1.138-1.386).

CONCLUSIONS

Our study provides new evidence that TRAIL 1595 C allele may be used as a low-penetrant risk factor for bladder cancer development in a Turkish population. Otherwise, gene-gene interaction analysis revealed that the DR4GG genotype may have a predominant effect on the increased risk of bladder cancer over the TRAIL CT genotype.

Restoring TRAIL mediated signaling in ovarian cancer cells

Ovarian cancer has emerged as a multifaceted and genomically complex disease. Genetic/epigenetic mutations, suppression of tumor suppressors, overexpression of oncogenes, rewiring of intracellular signaling cascades and loss of apoptosis are some of the deeply studied mechanisms. In vitro and in vivo studies have highlighted different molecular mechanisms that regulate tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) mediated apoptosis in ovarian cancer. In this review, we bring to limelight, expansion in understanding systematical characterization of ovarian cancer cells has led to the rapid development of new drugs and treatments to target negative regulators of TRAIL mediated signaling pathway. Wide ranging synthetic and natural agents have been shown to stimulate mRNA and protein expression of death receptors. This review is compartmentalized into programmed cell death protein 4, platelet-derived growth factor signaling and miRNA control of TRAIL mediated signaling to ovarian cancer. Mapatumumab and PRO95780 have been tested for efficacy against ovarian cancer. Use of high-throughput screening assays will aid in dissecting the heterogeneity of this disease and increasing a long-term survival which might be achieved by translating rapidly accumulating information obtained from molecular and cellular studies to clinic researches.

Biomarkers of liver cell death

Hepatocyte cell death during liver injury was classically viewed to occur by either programmed (apoptosis), or accidental, uncontrolled cell death (necrosis). Growing evidence from our increasing understanding of the biochemical and molecular mechanisms involved in cell demise has provided an expanding view of various modes of cell death that can be triggered during both acute and chronic liver damage such as necroptosis, pyroptosis, and autophagic cell death. The complexity of non-invasively assessing the predominant mode of cell death during a specific liver insult in either experimental in vivo models or in humans is highlighted by the fact that in many instances there is significant crosstalk and overlap between the different cell death pathways. Nevertheless, the realization that during cell demise triggered by a specific mode of cell death certain intracellular molecules such as proteins, newly generated protein fragments, or MicroRNAs are released from hepatocytes into the extracellular space and may appear in circulation have spurred a significant interest in the development of non-invasive markers to monitor liver cell death. This review focuses on some of the most promising markers, and their potential role in assessing the presence and severity of liver damage in humans.

Epidemiology of alcoholic and nonalcoholic fatty liver disease in China

The prevalence of patients presenting with fatty liver disease (FLD) in China has approximately doubled over the past two decades. At present, FLD, which is typically diagnosed by imaging, is highly prevalent (≈ 27% urban population) in China and is mainly related to obesity and metabolic syndrome (MetS). However, the percentage of alcoholic liver disease (ALD) among patients with chronic liver diseases in clinic is increasing as well, and a synergetic effect exists between heavy alcohol drinking and obesity in ALD. Prevalence figures reveal regional variations, with a median prevalence of ALD and nonalcoholic FLD (NAFLD) of 4.5% and 15.0%, respectively. The prevalence of NAFLD in children is 2.1%, although the prevalence increases to 68.2% among obese children. With the increasing pandemic of obesity and MetS in the general population, China is likely to harbor an increasing reservoir of patients with FLD. The risk factors for FLD resemble to those of Caucasian counterparts, but the ethnic-specific definitions of obesity and MetS are more useful in assessment of Chinese people. Therefore, FLD/NAFLD has become a most common chronic liver disease in China. Public health interventions are needed to halt the worldwide trend of obesity and alcohol abuse to ameliorate liver injury and to improve metabolic health.

Regulation of the human TRAIL gene

TRAIL is a member of the TNF superfamily that induces tumor-selective cell death by engaging the pro-apoptotic death receptors DR4 and DR5. The antitumor potential of the TRAIL pathway has been targeted by several therapeutic approaches including recombinant TRAIL and TRAIL-receptor agonist antibodies among others. Interest in sensitizing tumor cells to TRAIL-mediated apoptosis has driven investigations of TRAIL-receptor gene regulation, though regulation of the TRAIL gene has been less studied. Physiologically, TRAIL serves as a pro-apoptotic effector molecule in the immune surveillance of cancer that is conditionally expressed by immune cells upon stimulation via an interferon-response element that was identified in early studies of the TRAIL gene promoter. Here, we map the TRAIL gene promoter and review studies of TRAIL gene regulation that involve several modalities of gene regulation including transcription factors, epigenetics, single-nucleotide polymorphisms and functionally distinct isoforms.

Association between endometriosis and polymorphisms in tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), TRAIL receptor and osteoprotegerin genes and their serum levels

PURPOSE

To evaluate the relationship between endometriosis and polymorphisms in the genes encoding tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), TRAIL receptor (DR) and osteoprotegerin (OPG) and their serum levels in Korean women.

METHODS

A case-control study was conducted with 138 women with endometriosis and 214 women without endometriosis in academic medical center. TRAIL c.49G>A, c.592A>G, c.615A>G, and c.662T>C; DR4 c.626G>C and c.1322A>G; DR5 c.95C>T, c.200C>T, and c.72T>G; OPG -245T>G, c.9C>G, c.788A>C, and c.9938G>T polymorphisms were investigated and circulating levels of TRAIL and OPG were measured.

RESULTS

The TRAIL c.49G>A, c.615A>G, and c.662T>C; the DR4 c.626G>C; the DR5 c.72T>G; the OPG c.788A>C and c.9938G>T polymorphisms were not observed. The genotype distributions and allele frequencies of single or combined polymorphisms of TRAIL, DR4, DR5, and OPG measured in women with endometriosis were not different from those in women without endometriosis, regardless of endometriosis stage. Serum TRAIL and OPG levels were significantly lower in women with endometriosis than in women without endometriosis, but these levels did not show differences between early and advanced endometriosis.

CONCLUSIONS

Endometriosis is associated with circulating TRAIL and OPG levels in Korean women but not with the TRAIL, DR, and OPG polymorphisms.

Genetic factors associated with the presence and progression of nonalcoholic fatty liver disease: a narrative review

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world. Whereas insulin resistance and obesity are considered major risk factors for the development and progression of NAFLD, the genetic underpinnings are unclear. Before 2008, candidate gene studies based on prior knowledge of pathophysiology of fatty liver yielded conflicting results. In 2008, Romeo et al. published the first genome wide association study and reported the strongest genetic signal for the presence of fatty liver (PNPLA3, patatin-like phospholipase domain containing 3; rs738409). Since then, two additional genome wide scans were published and identified 9 additional genetic variants. Whereas these results shed light into the understanding of the genetics of NAFLD, most of associations have not been replicated in independent samples and, therefore, remain undetermined the significance of these findings. This review aims to summarize the understanding of genetic epidemiology of NAFLD and highlights the gaps in knowledge.

Genetic variants in candidate genes influencing NAFLD progression

Nonalcoholic fatty liver disease (NAFLD) is a metabolic disorder including simple steatosis and nonalcoholic steatohepatitis (NASH). Advanced stages of NASH result ultimately in fibrosis, cirrhosis, and hepatocarcinoma. A diagnosis of NASH entails an increased risk of both liver-related and cardiovascular mortality as worsening of the metabolic syndrome. Because of its escalation, many investigations have been performed to elucidate the pathophysiologic origins of the disease progression. Human epidemiologic studies describing polymorphisms in a number of genes involved in metabolic dysfunctions have contributed to clarify the causes leading to the disease evolution. In this review, we attempt to outline critically the most recently identified genetic variants in NAFLD patients to identify possible risk factors promoting the progression of the disease. The evaluation of altered genotypes together with other clinical variables may facilitate the clinical management of these patients.

Relevance of TNF-α gene polymorphisms in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease is one of the most prevalent liver diseases worldwide. Its etiology is multifactorial and genetic factors most likely play a role. Genome-wide association studies have identified the first candidate genes, including patatin-like phospholipase 3, a lipase that is involved in triglyceride metabolism. Several other genetic variants have been identified, although with less convincing evidence. These genetic variants encode for molecules regulating insulin signalling, lipid metabolism, inflammation or fibrogenesis. Whereas the biological functions of TNF-α have been demonstrated to play an important role in the regulation of insulin resistance, liver inflammation and lipid accumulation, further genetic studies are needed to clarify whether and which TNF-α genetic variants predispose to the development of nonalcoholic steatohepatitis, the inflammatory component of nonalcoholic fatty liver disease.

Apoptosis in nonalcoholic fatty liver disease: diagnostic and therapeutic implications

Pathological increases in cell death in the liver as well as in peripheral tissues has emerged as an important mechanism involved in the development and progression of nonalcoholic fatty liver disease (NAFLD). An increase in hepatocyte cell death by apoptosis is typically present in patients with NAFLD and in experimental models of steatohepatitis, while an increase in adipocyte cell death in visceral adipose tissue may be an important mechanism triggering insulin resistance and hepatic steatosis. The two fundamental pathways of apoptosis, the extrinsic (death receptor-mediated) and intrinsic (organelle-initiated) pathways, are both involved. This article summarizes the current knowledge related to the distinct molecular and biochemical pathways of cell death involved in NAFLD pathogenesis. In particular, it will highlight the efforts for the development of both novel diagnostic and therapeutic strategies based on this knowledge.

Cell death and nonalcoholic steatohepatitis: where is ballooning relevant?

Nonalcoholic fatty liver disease (NAFLD) is the most common form of liver disease in the Western world. Progression to more aggressive forms of liver injury, such as nonalcoholic steatohepatitis (NASH) and cirrhosis, occurs in less than a third of affected subjects. Human data and both in vivo and in vitro models demonstrate that cell death, particularly apoptosis, is increased in NAFLD and NASH patients, suggesting that it is crucial in disease progression. Indeed, fatty acids - more specifically, saturated fatty acids - strongly induce hepatocyte apoptosis. In addition, hepatic steatosis renders hepatocytes more susceptible to apoptotic injury. Ballooned hepatocytes and Mallory-Denk bodies are important hallmarks of NASH and correlate with disease progression. There are complex correlations between ballooning, Mallory-Denk bodies and apoptosis through keratin metabolism and depletion, as well as through the endoplasmic reticulum stress response. Whether apoptosis may promote hepatocellular ballooning, or vice versa, will be discussed in this article.

Is there any correlation between TNF-related apoptosis-inducing ligand (TRAIL) genetic variants and breast cancer?

INTRODUCTION

TNF-related apoptosis-inducing ligand (TRAIL) is a death ligand and also a member of the TNF superfamily. We aimed to investigate the possible relationship between TRAIL and breast cancer. Here, we report the results of the first association study on genetic variation in the TRAIL gene and its effect on breast cancer susceptibility and prognosis.

MATERIAL AND METHODS

A C/T polymorphism at 1595 position in exon 5 of the TRAIL gene was genotyped in a Turkish breast cancer case-control population including 53 cases (mean age: 55.09 ±11.63 years) and 57 controls (mean age: 57.17 ±17.48 years) using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis.

RESULTS

There were no differences in the distribution of TRAIL genotypes and frequencies of the alleles in the breast cancer patients and controls. A heterozygous TRAIL CT polymorphism in exon 5 was present in 8.3% of tumour stage III-IV and 48.8% of stage I-II patients, and in 42.1% of controls. The reduced frequency of this genotype in patients who had advanced tumour stage was statistically significant (p = 0.017).

CONCLUSIONS

Our findings indicate that genetic variants of TRAIL at position 1595 in exon 5 might be associated with progression of breast cancer.

Update on nonalcoholic fatty liver disease: genes involved in nonalcoholic fatty liver disease and associated inflammation

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) is one of the most prevalent liver diseases worldwide. Advanced age, extensive overweight and a number of features of the metabolic syndrome are associated with NAFLD severity. The cause of NAFLD is considered multifactorial with a substantial genetic component.

RECENT FINDINGS

Family members of children with NAFLD demonstrate a higher risk for NAFLD. Whereas such an association only suggests that familial factors are major determinants of whether or not an individual will develop NAFLD, recent genome-wide association studies were able to identify first candidate genes. An allele in patatin-like phospholipase 3, encoding a protein of unknown function with homology to lipid acyl hydrolases, is strongly associated with increased hepatic fat and inflammation. Apolipoprotein C3 gene variants are also associated with NAFLD and insulin resistance. Several other genetic variants have been identified, although with less convincing evidence. These genetic variants involve molecules regulating insulin signaling, lipid metabolism, oxidative stress or fibrogenesis. Furthermore, genetic variants of several cytokines and adipocytokines have been associated with NAFLD.

SUMMARY

Several genetic factors such as patatin-like phospholipase 3 or apolipoprotein C3 have been recently characterized in NAFLD. Further studies to identify their interaction with environmental factors are eagerly warranted.

Functional implication of TRAIL -716 C/T promoter polymorphism on its in vitro and in vivo expression and the susceptibility to sporadic breast tumor

Recently, TRAIL function has been elucidated beyond its known classical role of mediating cellular homeostasis and immune surveillance against transformed cells. Here, we show how CC genotype of -716 TRAIL promoter SNP rendered risk for sporadic breast cancer as compared to the CT and TT genotypes (P (recessive model) = 0.018, OR = 1.4, 95% CI = 1.1-1.9; P (allele model) = 0.010, OR = 1.3, 95% CI = 1.1-1.7). The in silico prediction of the introduction of core Sp1/Sp3-binding motif suggested the functional significance of the SNP variation. This functional implication was validated by luciferase assay in HeLa (P = 0.026), MCF-7 (P = 0.022), HepG2 (P = 0.024), and HT1080 (P = 0.030) cells and also by real-time expression studies on tumor tissues (P = 0.01), revealing the transcriptionally repressed status of -716 T when compared to -716 C allele. The SNP-SNP interactions reflected an enhanced protective effect of CT and TT genotypes with the protective genetic backgrounds of TP53-BRCA2 (P = 0.002, OR = 0.2, 95% CI = 0.1-0.6), IFNG (P = 0.0000002, OR = 0.3, 95% CI = 0.2-0.4), and common variant Casp8 (P = 0.0003, OR = 0.5, 95% CI = 0.3-0.7). Interestingly, a comparison with clinical parameters showed overrepresented CT and TT genotypes in progressing (P = 0.041) and ER/PR negative tumors (P = 0.024/0.006). This was explained by increased apoptotic index, calculated as a ratio of selected pro-apoptotic and anti-apoptotic gene expression profiles, in CC genotyped tumors, favoring either intrinsic (P = 0.008,0.018) or extrinsic (P = 0.025,0.217) pathway depending upon the ER/PR status. Our study reveals for the first time that a promoter SNP of TRAIL functionally modulates the gene and consequently its role in breast cancer pathogenesis, cautioning to consider the -716 TRAIL SNP status in patients undergoing TRAIL therapy.

TNF superfamily gene polymorphism as prognostic factor in early breast cancer

PURPOSE

Since apoptosis may play a role in the prognosis of breast cancer, the present study analyzed the polymorphisms of apoptosis-related genes and their impact on the survival of 240 patients with early invasive ductal breast cancer.

METHODS

The genomic DNA was extracted from paraffin-embedded tumor-free tissue or blood, and 12 single nucleotide polymorphisms (SNPs) of 11 apoptosis-related genes in the apoptosis pathway determined using a Sequenom MassARRAY system.

RESULTS

During the median follow-up of 53.4 (range 2.9-205.9) months, 37 relapses and 22 deaths occurred. Among the target polymorphisms, the tumor necrosis factor superfamily member 10 gene polymorphism (TNFSF10 rs1131532) in a recessive model of the T allele and prostaglandin-endoperoxide synthase 2 gene polymorphism (PTGS2 rs5275) in a dominant model of the C allele were associated with survival in a log-rank test. The TT genotype of TNFSF10 (rs1131532) was also significantly correlated with a lower disease-free, distant disease-free, and overall survival in a multivariate analysis (HR = 3.304, 4.757, and 6.459; P = 0.002, 0.001, and 0.009, respectively), while PTGS2 rs5275 was only associated with a higher distant disease-free survival (HR = 0.302; P = 0.041). No clinicopathologic difference was observed according to the genotypes of these two polymorphisms.

CONCLUSION

The TNFSF10 (rs1131532) polymorphism was identified as a possible prognostic factor of survival in patients with operated invasive breast cancer.