Possible Relevance of PNPLA3 and TLL1 Gene Polymorphisms to the Efficacy of PEG-IFN Therapy for HBV-Infected Patients

Association of PNPLA3 SNP With the Development of HBV-related Hepatocellular Carcinoma

BACKGROUND/AIM

Concomitant nonalcoholic fatty liver disease (NAFLD)/hepatic steatosis (HS) is suggested to increase the risk of hepatocellular carcinoma (HCC) in hepatitis virus B (HBV)-infected patients. Patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 gene single-nucleotide polymorphism (SNP) is well-known to be associated with the development of NAFLD/HS; however, it is still unclear whether this SNP is related to the development of HCC in HBV-infected patients.

PATIENTS AND METHODS

We investigated a total of 202 HBV-infected patients who received percutaneous liver biopsy, and simultaneously assessed biopsy-proven HS, insulin resistance, and the PNPLA3 SNP status. We further investigated the relationships of these factors with the development of HCC in HBV-infected patients.

RESULTS

Most of the enrolled cases (196/202: 97.0%) were non-cirrhotic patients. One hundred seventy-three patients (85.6%) received antiviral therapy. A Kaplan-Meier analysis showed that the incidence of HCC development in patients with HS was higher than that in patients without HS (p<0.01). An increased homeostasis model assessment as an index of insulin resistance (HOMA-IR) value (≥1.6) was associated not only with the presence of HS (p<0.0001) but also with the development of HCC (p<0.01). The PNPLA3 rs738409 SNP was also associated with the presence of HS (p<0.01) and the development of HCC (p<0.05) in HBV-infected patients.

CONCLUSION

In addition to HS and IR, PNPLA3 rs738409 SNP was suggested to be associated with the development of HCC in Japanese patients with HBV infection.

Impact of a Loss-of-Function Variant in HSD17B13 on Hepatic Decompensation and Mortality in Cirrhotic Patients

A common splice variant in HSD17B13 (rs72613567:TA) was recently found to be associated with a reduced risk of developing chronic liver disease in NAFLD patients and a reduced risk of progression to advanced fibrosis and cirrhosis. In this study, we aimed to evaluate the prognosis of cirrhotic patients harboring this variant. We performed a retrospective analysis on 483 prospectively recruited patients from four different hospitals in Spain, followed-up for at least 5 years. We collected clinical, demographic, and biochemical data, and we performed a genotyping analysis for common variants previously associated with liver disease risk (HSD17B13 rs72613567:TA and PNPLA3 rs738409). Patients homozygous for the TA allele showed a higher MELD score (p = 0.047), Child−Turcotte−Pugh score (p = 0.014), and INR levels (p = 0.046), as well as decreased albumin (p = 0.004) at baseline. After multivariate analysis, patients with the “protective” variant indeed had an increased risk of hepatic decompensation [aHR 2.37 (1.09−5.06); p = 0.029] and liver-related mortality [aHR 2.32 (1.20−4.46); p = 0.012]. Specifically, these patients had an increased risk of developing ascites (Log-R 11.6; p < 0.001), hepatic encephalopathy (Log-R 10.2; p < 0.01), and higher mortality (Log-R 14.1; p < 0.001) at 5 years of follow-up. Interactions with the etiology of the cirrhosis and with the variant rs738409 in PNPLA3 are also described. These findings suggest that the variant rs72613567:TA in HSD17B13 has no protective effect, but indeed increases the risk of decompensation and death in patients with advanced chronic liver disease.

Update on Non-Alcoholic Fatty Liver Disease-Associated Single Nucleotide Polymorphisms and Their Involvement in Liver Steatosis, Inflammation, and Fibrosis: A Narrative Review

Genetic factors are involved in the development, progression, and severity of NAFLD. Polymorphisms in genes regulating liver functions may increase liver susceptibility to NAFLD. Therefore, we conducted this literature study to present recent findings on NAFLD-associated polymorphisms from published articles in PubMed from 2016 to 2021. From 69 selected research articles, 20 genes and 34 SNPs were reported to be associated with NAFLD. These mutated genes affect NAFLD by promoting liver steatosis (PNPLA3, MBOAT7, TM2SF6, PTPRD, FNDC5, IL-1B, PPARGC1A, UCP2, TCF7L2, SAMM50, IL-6, AGTR1, and NNMT), inflammation (PNPLA3, TNF-α, AGTR1, IL-17A, IL-1B, PTPRD, and GATAD2A), and fibrosis (IL-1B, PNPLA3, MBOAT7, TCF7L2, GATAD2A, IL-6, NNMT, UCP, AGTR1, and TM2SF6). The identification of these genetic factors helps to better understand the pathogenesis pathways of NAFLD

Implications of the Immune Polymorphisms of the Host and the Genetic Variability of SARS-CoV-2 in the Development of COVID-19

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is responsible for the current pandemic affecting almost all countries in the world. SARS-CoV-2 is the agent responsible for coronavirus disease 19 (COVID-19), which has claimed millions of lives around the world. In most patients, SARS-CoV-2 infection does not cause clinical signs. However, some infected people develop symptoms, which include loss of smell or taste, fever, dry cough, headache, severe pneumonia, as well as coagulation disorders. The aim of this work is to report genetic factors of SARS-CoV-2 and host-associated to severe COVID-19, placing special emphasis on the viral entry and molecules of the immune system involved with viral infection. Besides this, we analyze SARS-CoV-2 variants and their structural characteristics related to the binding to polymorphic angiotensin-converting enzyme type 2 (ACE2). Additionally, we also review other polymorphisms as well as some epigenetic factors involved in the immunopathogenesis of COVID-19. These factors and viral variability could explain the increment of infection rate and/or in the development of severe COVID-19.

A Missense Variant in Granulysin is Associated with the Efficacy of Pegylated-Interferon-Alpha Therapy in Chinese Patients with HBeAg-Positive Chronic Hepatitis B

Purpose

Granulysin (GNLY) is a cytotoxic granule that has been reported to have various antimicrobial activities. We evaluated the association between a missense variant in GNLY (rs11127) and treatment efficacy of pegylated interferon-alpha (PegIFNα) or nucleos(t)ide analogs (NUCs) in patients with chronic hepatitis B (CHB).

Patients and Methods

We included a total of 1823 patients with hepatitis B e antigen (HBeAg)-positive CHB (954 patients treated with PegIFNα and 869 patients treated with NUCs) in four Phase IV multicenter randomized controlled trials. The association of the GNLY rs11127 genotype with the combined response (CR), defined as HBeAg seroconversion and hepatitis B virus (HBV) DNA level <2000 IU/mL was evaluated. A polygenic score (PGS) was constructed to evaluate the cumulative effect of multiple single-nucleotide polymorphisms (SNPs), including rs11127 and several other SNPs, STAT4 rs7574865, CFB rs12614, and CD55 rs28371597, which were reported to be associated with CR.

Results

GNLY rs11127 was significantly associated with CR in patients treated with PegIFNα. The CR rate in patients with the rs11127 CC genotype was higher than that with the CT or TT genotype (40.98% vs 30.34% or 27.09%, P = 0.003). Furthermore, a PGS integrating GNLY rs11127 and three other SNPs was significantly associated with CR in PegIFNα-treated patients (P < 0.001). However, no significant correlation was found between GNLY rs11127 and CR in NUCs-treated patients.

Conclusion

GNLY rs11127 is an independent biomarker for predicting the response to PegIFNα therapy in HBeAg-positive CHB patients. Furthermore, the PGS, including GNLY rs11127, provides new insights for individualized treatment in clinical practice.

Is HSD17B13 Genetic Variant a Protector for Liver Dysfunction? Future Perspective as a Potential Therapeutic Target

As diet and lifestyle have changed, fatty liver disease (FLD) has become more and more prevalent. Many genetic risk factors, such as variants of PNPLA3, TM6SF2, GCKR, and MBOAT7, have previously been uncovered via genome wide association studies (GWAS) to be associated with FLD. In 2018, a genetic variant (rs72613567, T > TA) of hydroxysteroid 17-β dehydrogenase family 13 (HSD17B13) was first associated with a lower risk of developing alcoholic liver disease and non-alcoholic fatty liver disease (NAFLD) in minor allele carriers. Other HSD17B13 variants were also later linked with either lower inflammation scores among NAFLD patients or protection against NAFLD (rs6834314, A > G and rs9992651, G > A) respectively. HSD17B13 is a lipid droplet-associated protein, but its function is still ambiguous. Compared to the other genetic variants that increase risk for FLD, HSD17B13 variants serve a protective role, making this gene a potential therapeutic target. However, the mechanism by which these variants reduce the risk of developing FLD is still unclear. Because studies in cell lines and mouse models have produced conflicting results, human liver tissue modeling using induced pluripotent stem cells may be the best way to move forward and solve this mystery.

Association between Interferon-Lambda-3 rs12979860, TLL1 rs17047200 and DDR1 rs4618569 Variant Polymorphisms with the Course and Outcome of SARS-CoV-2 Patients

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection provides a critical host-immunological challenge.

AIM

We explore the effect of host-genetic variation in interferon-lambda-3 rs12979860, Tolloid Like-1 (TLL1) rs17047200 and Discoidin domain receptor 1(DDR1) rs4618569 on host response to respiratory viral infections and disease severity that may probe the mechanistic approach of allelic variation in virus-induced inflammatory responses.

METHODS

141 COVID-19 positive patients and 100 healthy controls were tested for interferon-lambda-3 rs12979860, TLL1 rs17047200 and DDR1 rs4618569 polymorphism by TaqMan probe-based genotyping. Different genotypes were assessed regarding the COVID-19 severity and prognosis.

RESULTS

There were statistically significant differences between the studied cases and control group with regard to the presence of comorbidities, total leucocytic count, lymphocytic count, CRP, serum LDH, ferritin and D-dimer (p < 0.01). The CC genotype of rs12979860 cytokine, the AA genotype of TLL1 rs17047200 and the AA genotype of the rs4618569 variant of DDR1 showed a higher incidence of COVID-19 compared to the others. There were significant differences between the rs4618569 variant of DDR and the outcome of the disease, with the highest mortality in AG genotype 29 (60.4%) in comparison to 16 (33.3%) and 3 (6.2%) in the AA and GG genotypes, respectively (p = 0.007*), suggesting that the A allele is associated with a poor outcome in the disease.

CONCLUSION

Among people who carry C and A alleles of SNPs IFN-λ rs12979860 and TLL1 rs17047200, respectively, the AG genotype of the DDR1 rs4618569 variant is correlated with a COVID-19 poor outcome. In those patients, the use of anti-IFN-λ 3, TLL1 and DDR1 therapy may be promising for personalized translational clinical practice.