Lack of association between the CARD10 rs6000782 polymorphism and type 1 autoimmune hepatitis in a Japanese population

CARMA3: A potential therapeutic target in non-cancer diseases

Caspase recruitment domain and membrane-associated guanylate kinase-like protein 3 (CARMA3) is a scaffold protein widely expressed in non-hematopoietic cells. It is encoded by the caspase recruitment domain protein 10 (CARD10) gene. CARMA3 can form a CARMA3-BCL10-MALT1 complex by recruiting B cell lymphoma 10 (BCL10) and mucosa-​associated lymphoid tissue lymphoma translocation protein 1 (MALT1), thereby activating nuclear factor-​κB (NF-κB), a key transcription factor that involves in various biological responses. CARMA3 mediates different receptors-dependent signaling pathways, including G protein-coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs). Inappropriate expression and activation of GPCRs and/or RTKs/CARMA3 signaling lead to the pathogenesis of human diseases. Emerging studies have reported that CARMA3 mediates the development of various types of cancers. Moreover, CARMA3 and its partners participate in human non-cancer diseases, including atherogenesis, abdominal aortic aneurysm, asthma, pulmonary fibrosis, liver fibrosis, insulin resistance, inflammatory bowel disease, and psoriasis. Here we provide a review on its structure, regulation, and molecular function, and further highlight recent findings in human non-cancerous diseases, which will provide a novel therapeutic target.

Genetic aspects of adult and pediatric autoimmune hepatitis: A concise review

Autoimmune Hepatitis (AIH) is a heterogenous, mostly chronic liver disease that affects people of all age groups, women more often than men. The aim of therapy is to prevent cirrhosis, as it mainly accounts for liver-related mortality in patients with AIH. Rates of remission are high in patients with AIH, but life-long immunosuppressive therapy is required. AIH is hypothesized to originate from immunologic reactivity targeted against mostly unknown self-antigens, potentially triggered by viral infections among other factors. While AIH does not follow a Mendelian inheritance pattern, part of the risk of developing AIH or worse disease course, is attributed to specific genetic risk factors. Major associations for the risk of development of AIH were found for HLA-DRB1*03:01 and HLA-DRB1*04:01 in adult AIH in the only genome-wide association study on AIH. However, other potential risk loci in SH2B3, CARD10 and KIR genes were described. This review covers the current knowledge on genetic risk factors in adult and pediatric AIH.

Genetic risk factors for autoimmune hepatitis: implications for phenotypic heterogeneity and biomarkers for drug response

Autoimmune hepatitis (AIH) is a rare chronic progressive liver disease with autoimmune features. It mainly affects middle-aged women. AIH is occasionally complicated with liver cirrhosis that worsens the prognosis. Genetic and environmental factors are involved in the pathogenesis of AIH. Genetic studies of other diseases have been revealing of pathogenesis and drug efficacy. In this review, we summarize the genetic risk factors for AIH, including human leukocyte antigen (HLA) and non-HLA genes. A genome-wide association study (GWAS) on European AIH revealed the strongest associations to be with single nucleotide variants (SNVs) in HLA. Predisposing alleles for AIH were DRB1*03:01 and DRB1*04:01 in Europeans; DRB1*04:04, DRB1*04:05, and DRB1*13:01 in Latin Americans; and DRB1*04:01 and DRB1*04:05 in Japanese. Other risk SNVs in non-HLA genes for AIH were found by a candidate gene approach, but several SNVs were confirmed in replication studies. Some genetic factors of AIH overlapped with those of other autoimmune diseases. Larger-scale GWASs of other ethnic groups are required. The results of genetic studies might provide an explanation for the phenotypic heterogeneity of AIH and biomarkers for drug responses.

Association of CARD10 rs6000782 and TNF rs1799724 variants with paediatric-onset autoimmune hepatitis

Although the pathogenesis of paediatric-onset autoimmune hepatitis (pAIH) remains incompletely understood, genetic variants and environmental factors are known to be involved. Caspase recruitment domain family member 10 (CARD10) is a scaffold protein that participates in a complex pathway activating nuclear factor kappa-B (NFκB) and tumour necrosis factor alpha (TNF-α). This study aimed to investigate the association of CARD10 rs6000782 (g.37928186A > C) and TNF gene promoter rs1799724 (c.-1037C > T) variants with pAIH susceptibility in a cohort of Egyptian children. The research was also extended to assess the relationship of these variants with levels of NFκB-p65 and TNF-α. Fifty-six pAIH patients and 44 age- and sex-matched healthy controls were included. Variant genotyping was performed by polymerase chain reaction (PCR). Serum NFκB-p65 and TNF-α levels were measured using enzyme-linked immunosorbent assays (ELISAs). rs6000782 C and rs1799724 T alleles, separate or in combination, were significantly increased in pAIH patients compared to controls. Serum levels of NFκB-p65 and TNF-α were higher in pAIH differentiating both groups. Moreover, the recessive model of rs6000782 revealed a significant association with the levels of both NFκB-p65 and TNF-α. In conclusion, rs6000782 and rs1799724 variants are potential genetic risk factors for pAIH predisposition, with the former affecting NFκB-p65 and TNF-α levels. Overall, the inflammatory cascade was associated with the degree of liver cell destruction. Clinically, screening and genetic counselling are recommended for relatives of pAIH patients.

Epigenetic changes and their implications in autoimmune hepatitis

BACKGROUND

The genetic risk of autoimmune hepatitis is insufficient to explain the observed risk, and epigenetic changes may explain disparities in disease occurrence in different populations within and between countries. The goal of this review was to examine how epigenetic changes induced by the environment or inherited as a phenotypic trait may affect autoimmune hepatitis and be amenable to therapeutic intervention.

MATERIALS AND METHODS

Pertinent abstracts were identified in PubMed by multiple search terms. The number of abstracts reviewed was 1689, and the number of full-length articles reviewed exceeded 150.

RESULTS

Activation of pro-inflammatory genes in autoimmune disease is associated with hypomethylation of deoxyribonucleic acid and modification of histones within chromatin. Organ-specific microribonucleic acids can silence genes by marking messenger ribonucleic acids for degradation, and they can promote inflammatory activity or immunosuppression. High circulating levels of the microribonucleic acids 21 and 122 have been demonstrated in autoimmune hepatitis, and they may increase production of pro-inflammatory cytokines. Microribonucleic acids are also essential for maintaining regulatory T cells. Drugs, pollutants, infections, diet and ageing can induce inheritable epigenetic changes favouring autoimmunity. Reversal is feasible by manipulating enzymes, transcription factors, gene-silencing molecules and toxic exposures or by administering methyl donors and correcting vitamin D deficiency. Gene targets, site specificity, efficacy and consequences are uncertain.

CONCLUSIONS

Potentially reversible epigenetic changes may affect the occurrence and outcome of autoimmune hepatitis, and investigations are warranted to determine the nature of these changes, key genomic targets, and feasible interventions and their consequences.

Association of a single nucleotide polymorphism in TNIP1 with type-1 autoimmune hepatitis in the Japanese population

Several studies reported that autoimmune diseases share a number of susceptibility genes. Of these genes, a SNP rs7708392 in TNIP1 was reported to be associated with systemic lupus erythematosus (SLE). Autoimmune hepatitis (AIH), a rare chronic progressive liver disease, shares some clinical features with SLE. Therefore, we investigated whether the SNP is associated with Japanese AIH. An association study of rs7708392 was conducted in 343 Japanese AIH patients and 828 controls. We found that rs7708392 is associated with AIH (P = 0.0236, odds ratio (OR) 1.26, 95% confidence interval (CI): 1.03-1.54), under the allele model for C allele. Significant differences of clinical characteristics of the AIH patients with or without G allele of rs7708392 were not detected. Of interest, the association was stronger in AIH without HLA-DRB1*04:05 allele (P = 0.0063, Q = 0.0127, OR 1.48, 95% CI: 1.12-1.96), though the association was not detected in AIH with DRB1*04:05. The C allele of rs7708392 was associated with AIH, especially AIH without DRB1*04:05, an already established risk factor.

Review article: next-generation transformative advances in the pathogenesis and management of autoimmune hepatitis

BACKGROUND

Advances in autoimmune hepatitis that transform current concepts of pathogenesis and management can be anticipated as products of ongoing investigations driven by unmet clinical needs and an evolving biotechnology.

AIM

To describe the advances that are likely to become transformative in autoimmune hepatitis, based on the direction of current investigations.

METHODS

Pertinent abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and a secondary bibliography was developed. The discovery process was repeated, and a tertiary bibliography was identified. The number of abstracts reviewed was 2830, and the number of full-length articles reviewed exceeded 150.

RESULTS

Risk-laden allelic variants outside the major histocompatibility complex (rs3184504, r36000782) are being identified by genome-wide association studies, and their gene products are potential therapeutic targets. Epigenetic changes associated with environmental cues can enhance the transcriptional activity of genes, and chromatin re-structuring and antagonists of noncoding molecules of ribonucleic acid are feasible interventions. The intestinal microbiome is a discovery field for microbial products and activated immune cells that may translocate to the periphery and respond to manipulation. Epidemiological studies and controlled interview-based surveys may implicate environmental and xenobiotic factors that warrant evidence-based changes in lifestyle, and site-directed molecular and cellular interventions promise to change the paradigm of treatment from one of blanket immunosuppression.

CONCLUSIONS

Advances in genetics, epigenetics, pathophysiology, epidemiology, and site-directed molecular and cellular interventions constitute the next generation of transformative advances in autoimmune hepatitis.

Similarities and Differences in Autoimmune Hepatitis Epidemiology between East and West: Autoimmune Hepatitis in East Asia, Southeast Asia, and South Asia

Background

Autoimmune hepatitis (AIH) is a relatively rare disease that can develop regardless of age or ethnicity. However, its clinical features differ between eastern and western populations due to several heterogeneous genetic and environmental factors. We herein report the clinical characteristics of AIH patients in East Asia, Southeast Asia, and South Asia.

Summary and Key Messages

The prevalence of AIH in eastern countries is considered to be lower than in western countries. Although a few young patients with type 2 AIH have been observed in South Asia, most patients in Asia are middle-aged women with type 1 AIH who respond well to steroid-based immunosuppressive therapy. Human leukocyte antigen DR4 is suggested to be an influential factor in the genetic background of AIH patients in Asia, particularly in East Asia. Notably, AIH may be induced by some societal- or culture-associated medicines, including herbal medicines. The IAIHG (International Autoimmune Hepatitis Group) scoring systems are generally accepted as the standard diagnostic methods for AIH in Asian countries. The results of repeated nationwide surveys in Japan suggest that the clinical features of AIH patients in East Asia are changing, with IgG levels and rates of anti-nuclear antibody positivity decreasing.

Association of a single nucleotide polymorphism upstream of ICOS with Japanese autoimmune hepatitis type 1

Autoimmune hepatitis (AIH) is an uncommon chronic autoimmune liver disease. Several studies reported the association of polymorphisms between CD28, CTLA4 and ICOS gene cluster in 2q33.2 with autoimmune or inflammatory diseases. The previous genome-wide association study on type 1 AIH in a European population has reported a risk G allele of a single nucleotide polymorphism (SNP), rs4325730, in this region. Here, we conducted an association study of this SNP with type 1 AIH in a Japanese population, as a replication study.An association study of rs4325730 was conducted in 343 Japanese AIH patients and 315 controls.We found that rs4325730 is associated with AIH (P=0.0173, odds ratio (OR) 1.30, 95% confidence interval (CI) 1.05-1.62, under the allele model for G allele, P=0.0070, OR 1.62, 95% CI 1.14-2.31, under the dominant model for G allele). This SNP was strongly associated with definite AIH (P=0.0134, OR 1.36, 95% CI 1.07-1.74; under allele model for G, P=0.0035, OR 1.85, 95% CI 1.22-2.81, under dominant model for G).This is the first replication association study of rs4325730 upstream of ICOS with AIH in the Japanese population and rs4325730G is a risk allele.