Melatonin Protects Cholangiocytes from Oxidative Stress-Induced Proapoptotic and Proinflammatory Stimuli via miR-132 and miR-34

Biosynthesis of melatonin by cholangiocytes is essential for maintaining the function of biliary epithelium. However, this cytoprotective mechanism appears to be impaired in primary biliary cholangitis (PBC). MiR-132 has emerged as a mediator of inflammation in chronic liver diseases. The effect of melatonin on oxidative stress and bile acid-induced apoptosis was also examined in cholangiocyes overexpressing miR506, as a PBC-like cellular model. In PBC patients the serum levels of melatonin were found increased in comparison to healthy controls. Whereas, in cholangiocytes within cirrhotic PBC livers the melatonin biosynthetic pathway was substantially suppressed even though the expressions of melatonin rate-limiting enzyme aralkylamine N-acetyltransferase (AANAT), and CK-19 (marker of cholangiocytes) were enhanced. In cholangiocytes exposed to mitochondrial oxidative stress melatonin decreased the expression of proapoptotic stimuli (PTEN, Bax, miR-34), which was accompanied by the inhibition of a pivotal mediator of inflammatory response Nf-κB-p65 and the activation of antiapoptotic signaling (miR-132, Bcl2). Similarly, melatonin reduced bile acid-induced proapoptotic caspase 3 and Bim levels. In summary, the insufficient hepatic expression of melatonin in PBC patients may predispose cholangiocytes to oxidative stress-related damage. Melatonin, via epigenetic modulation, was able to suppress NF-κB signaling activation and protect against biliary cells apoptotic signaling.This work was supported by grant no. 2015/17/B/NZ5/02541 from National Science Centre in Poland

TRAF1-C5

Background. Previous studies reported associations between specific alleles of non-HLA immunoregulatory genes and higher fatigue scores in patients with primary biliary cirrhosis (PBC). Aim. To study the relationship between variables of health-related quality of life (HRQoL) and single nucleotide polymorphisms of TRAF1-C5, a member of the tumor necrosis factor receptor family. Patients and Methods. TRAF1-C5 gene polymorphisms, rs2900180 and rs3761847, were analysed in 120 Caucasian PBCs. The HRQoL was assessed with SF-36, PBC-40, and PBC-27 questionnaires. Results. We found a negative association between TT genotype of rs2900180 and SF-36’s domains vitality (P<0.05), mental health (P<0.05), and mental component summary score (P<0.05). GG homozygotes of rs3761847 had lower vitality (P<0.05), mental health (P<0.05), mental component summary score (P<0.05) and impairment of social functioning (P<0.01). Allelic analysis has shown that T allele of rs2900180 and G allele of rs3761847 related to SF-36’s vitality (P<0.05 and P<0.01), social functioning (P<0.05 and P<0.05), mental health (P<0.01 and P<0.05), and mental component summary score (P<0.01 and P<0.05), respectively. Genotyping and allelic analysis did not reveal correlation with PBC-40 and PBC-27 domains. Conclusion. The association between rs2900180 and rs3761847 polymorphisms and HRQoL variables indicates that TRAF1 is involved in the induction of impaired QoL in PBC

Analysis for genotyping Duffy blood group in inhabitants of Sudan, the Fourth Cataract of the Nile

<p>Abstract</p> <p>Background</p> <p>Genetic polymophisms of the Duffy antigen receptor for the chemokines (DARC) gene successfully protected against blood stage infection by <it>Plasmodium vivax </it>infection. The Fy (a-, b-) phenotype is predominant among African populations, particularly those originating from West Africa, and it is rare among non-African populations. The aim of this study was to analyse the frequency of four Duffy blood groups based on SNPs (T-33C, G125A, G298A and C5411T) in two local tribes of Sudanese Arabs, the <it>Shagia </it>and <it>Manasir</it>, which are both from the region of the Fourth Nile cataract in Sudan.</p> <p>Methods</p> <p>An analysis of polymorphisms was performed on 217 individuals (126 representatives of the <it>Shagia </it>tribe and 91 of the <it>Manasir)</it>. Real-time PCR and TaqMan Genotyping Assays were used to study the prevalence of alleles and genotypes.</p> <p>Results</p> <p>The analysis of allelic and genotype frequency in the T-33C polymorphisms demonstrated a significant dominance of the <it>C </it>allele and <it>CC </it>genotype (OR = 0.53 [0.32-0.88]; p = 0.02) in both tribes. The G125A polymorphism is associated with phenotype Fy(a-, b-) and was identified in 83% of <it>Shagia </it>and 77% of <it>Manasir</it>. With regard to G298A polymorphisms, the genotype frequencies were different between the tribes (p = 0,002) and no single <it>AA </it>homozygote was found. Based on four SNPs examined, 20 combinations of genotypes for the <it>Shagia </it>and <it>Manasir </it>tribes were determined. The genotype <it>CC/AA/GG/CT </it>occurred most often in <it>Shagia </it>tribe (45.9%) but was rare in the <it>Manasir </it>tribe (6.6%) (p < 0.001 <it>Shagia </it>versus <it>Manasir</it>). The <it>FY*A^ES</it>allele was identified in both analysed tribes. The presence of individuals with the <it>FY*A/FY*A </it>genotype was demonstrated only in the <it>Shagia </it>tribe.</p> <p>Conclusion</p> <p>This is probably the first report showing genotypically Duffy-negative people who carry both <it>FY*B^ES</it>and <it>FY*A^ES</it>. The identification of the <it>FY*A^ES</it>allele in both tribes may be due to admixture of the non-African genetic background. Taken as a whole, allele and genotype frequencies between the <it>Shagia </it>and the <it>Manasir </it>were statistically different. However, the presence of individuals with the <it>FY*A/FY*A </it>genotype was demonstrated only in the <it>Shagia </it>tribe.</p

ApaI polymorphism of vitamin D receptor affects health-related quality of life in patients with primary sclerosing cholangitis.

BACKGROUND:Polymorphisms of vitamin D receptor (VDR) contribute to the pathogenesis of multiple autoimmune conditions. METHODS:We investigated the incidence of VDR polymorphisms (rs1544410-BsmI; rs7975232-ApaI; rs731236-TaqI) in a group of patients with primary sclerosing cholangitis (PSC, n = 275) and in healthy controls (n = 376). Additionally, correlations of the VDR polymorphisms with clinical and biochemical factors of the disease were analysed. RESULTS:The genotype and allele distributions of these polymorphisms in PSC patients were similar to those observed in controls. However, the ApaI polymorphism was associated with an impaired health-related quality of life (HRQoL). The generic SF-36 questionnaire showed that the Role-Physical (p = 0.01), Role-Emotional (p = 0.01), Physical Component Summary (p = 0.01) and Mental Component Summary (p = 0.003) scores were significantly affected. Similarly, the disease-specific questionnaires, PBC-40 and PBC-27, demonstrated that carriers of the C allele suffered from more severe Itch (p = 0.03 assessed by PBC-40 and PBC-27), more Fatigue (p = 0.02 assessed by PBC-40 and PBC-27) and Impaired Cognitive Capacity (p = 0.04 and p = 0.03). Correspondingly, individuals who were AA homozygotes (non-carriers of the C allele of ApaI) had higher summary scores for the Physical (p = 0.01) and Mental Components (p = 0.006) measured with SF-36. Moreover, they experienced less itch (p = 0.03) and less Fatigue (p = 0.03) and had better Cognitive Abilities (p = 0.04) as assessed by the PBC-40 and PBC-27 questionnaires. No associations between other VDR polymorphisms and clinical or laboratory findings were made. CONCLUSION:In summary, this study is the first to show that the ApaI polymorphisms in VDR may exert an effect on disease-related symptoms and quality of life in patients with PSC

Modulation of Mismatch Repair and the SOCS1/p53 Axis by microRNA-155 in the Colon of Patients with Primary Sclerosing Cholangitis

Deficient mismatch repair (MMR) proteins may lead to DNA damage and microsatellite instability. Primary sclerosing cholangitis (PSC) is a risk factor for colitis-associated colon cancer. MiR-155 is suggested to act as a key regulating node, linking inflammation and tumorigenesis. However, its involvement in the chronic colitis of PSC-UC patients has not been examined. We investigated the involvement of miR-155 in the dysregulation of MMR genes and colitis in PSC patients. Colon tissue biopsies were obtained from patients with PSC, PSC with concomitant ulcerative colitis (PSC-UC), uncomplicated UC, and healthy controls (n = 10 per group). In the ascending colon of PSC and PSC-UC patients, upregulated miR-155 promoted high microsatellite instability and induced signal transducer and activator of transcription 3 (STAT-3) expression via the inhibition of suppressors of cytokine signalling 1 (SOCS1). In contrast, the absence of miR-155 overexpression in the sigmoid colon of PSC-UC patients activated the Il-6/S1PR1 signalling pathway and imbalanced the IL17/FOXP3 ratio, which reinforces chronic colitis. Functional studies on human intestinal epithelial cells (HT-29 and NCM460D) confirmed the role of miR-155 over-expression in the inhibition of MMR genes and the modulation of p53. Moreover, those cells produced more TNF&alpha; upon a lipopolysaccharide challenge, which led to the suppression of miR-155. Additionally, exposure to bile acids induced upregulation of miR-155 in Caco-2 cell lines. Thus, under different conditions, miR-155 is involved in either neoplastic transformation in the ascending colon or chronic colitis in the sigmoid colon of patients with PSC. New insight into local modulation of microRNAs, that may alter the course of the disease, could be used for further research on potential therapeutic applications

Suppression of Hepatic PPAR&alpha; in Primary Biliary Cholangitis Is Modulated by miR-155

Background: PPAR&alpha; is a ligand-activated transcription factor that shows protective effects against metabolic disorders, inflammation and apoptosis. Primary biliary cholangitis and primary sclerosing cholangitis result in the intrahepatic accumulation of bile acids that leads to liver dysfunction and damage. Small, non-coding RNAs such as miR-155 and miR-21 are associated with silencing PPAR&alpha;. Methods: The expression of miR-155, miR-21 and PPAR&alpha; were evaluated using real-time PCR on liver tissue, as well as on human hepatocytes (HepG2) or cholangiocytes (NHCs) following exposure to lipopolysaccharide (LPS), glycodeoxycholic acid (GCDCA), lithocholic acid (LCA) and/or ursodeoxycholic acid (UDCA). Results: A reduction of PPAR&alpha; in primary biliary cholangitis (PBC) livers was associated with miR-21 and miR-155 upregulation. Experimental overexpression of either miR-155 or miR-21 inhibited PPAR&alpha; in hepatocytes, whereas, in cholangiocytes, only miR-21 suppressed PPAR&alpha;. Both GCDCA and LCA induced the cell type-specific upregulation of miR-155 or miR-21. In HepG2, LPS-induced miR-155 expression was blocked by a cotreatment with UDCA and was associated with PPAR&alpha; upregulation. In NHC cells, the expression of miR-21 was induced by LPS but did not affect PPAR&alpha; expression. Conclusions: Hepatic PPAR&alpha; expression is reduced in PBC livers as a likely result of miR-155 overexpression. UDCA effectively reduced both baseline and LPS-induced miR-155 expression, thus preventing the suppression of PPAR&alpha;

Decreased Expression of Vitamin D Receptor Affects an Immune Response in Primary Biliary Cholangitis via the VDR-miRNA155-SOCS1 Pathway

Primary biliary cholangitis (PBC) is an immune-mediated cholestatic disease. Vitamin D receptor (VDR)-dependent signaling constrains an inflammatory response by targeting the miRNA155-SOCS1 (suppressor of cytokine signaling 1) axis. The VDR-miRNA155-SOCS1 pathway was investigated in the context of the autoimmune response associated with PBC. Human liver tissues from non-cirrhotic PBC (n = 22), cirrhotic PBC (n = 22), cirrhotic primary sclerosing cholangitis (PSC, n=13), controls (n = 23), and peripheral blood mononuclear cells (PBMC) obtained from PBC (n = 16) and PSC (n = 10) patients and healthy subjects (n = 11) were used for molecular analyses. VDR mRNA and protein expressions were substantially reduced in PBC livers (51% and 59%, respectively). Correspondingly, the decrease of SOCS1 protein expression in PBC livers, after normalization to a marker of lymphocytes and forkhead family transcriptional regulator box P3 (FOXP3, marker of Treg), was observed, and this phenomenon was accompanied by enhanced miRNA155 expression. In PSC livers, protein expressions of VDR and SOCS1 were comparable to the controls. However, in PBM cells, protein expressions of VDR and SOCS1 were considerably decreased in both PBC and PSC. We demonstrated that VDR/miRNA155-modulated SOCS1 expression is decreased in PBC which may lead to insufficient negative regulation of cytokine signaling. These findings suggest that the decreased VDR signaling in PBC could be of importance in the pathogenesis of PBC

Relationship between the rs7975232 VDR polymorphisms and features of the SF-36, PBC-40 and PBC-27 questionnaires.

<p>Relationship between the rs7975232 VDR polymorphisms and features of the SF-36, PBC-40 and PBC-27 questionnaires.</p

Allele association for <i>VDR</i> in patients with PSC and control subjects.

<p>Allele association for <i>VDR</i> in patients with PSC and control subjects.</p

Demographic data of analysed subjects.

<p>Demographic data of analysed subjects.</p