Identification of an Endoglin Variant Associated With HCV-Related Liver Fibrosis Progression by Next-Generation Sequencing

Unveiling the Impact of BMP9 in Liver Diseases: Insights into Pathogenesis and Therapeutic Potential

Bone morphogenetic proteins (BMPs) are a group of growth factors belonging to the transforming growth factor β(TGF-β) family. While initially recognized for their role in bone formation, BMPs have emerged as significant players in liver diseases. Among BMPs with various physiological activities, this comprehensive review aims to delve into the involvement of BMP9 specifically in liver diseases and provide insights into the complex BMP signaling pathway. Through an enhanced understanding of BMP9, we anticipate the discovery of new therapeutic options and potential strategies for managing liver diseases.

TGF-β superfamily co-receptors in cancer

Transforming growth factor-β (TGF-β) superfamily signaling via their cognate receptors is frequently modified by TGF-β superfamily co-receptors. Signaling through SMAD-mediated pathways may be enhanced or depressed depending on the specific co-receptor and cell context. This dynamic effect on signaling is further modified by the release of many of the co-receptors from the membrane to generate soluble forms that are often antagonistic to the membrane-bound receptors. The co-receptors discussed here include TβRIII (betaglycan), endoglin, BAMBI, CD109, SCUBE proteins, neuropilins, Cripto-1, MuSK, and RGMs. Dysregulation of these co-receptors can lead to altered TGF-β superfamily signaling that contributes to the pathophysiology of many cancers through regulation of growth, metastatic potential, and the tumor microenvironment. Here we describe the role of several TGF-β superfamily co-receptors on TGF-β superfamily signaling and the impact on cellular and physiological functions with a particular focus on cancer, including a discussion on recent pharmacological advances and potential clinical applications targeting these co-receptors.

Human inborn errors of immunity to oncogenic viruses

Oncoviruses are viruses that can cause tumors. Seven viruses are currently recognized as oncogenic in humans: Epstein Barr virus (EBV), Kaposi sarcoma-associated herpesvirus (KSHV, also known as HHV8), human papillomaviruses (HPVs), hepatitis B virus (HBV), hepatitis C virus (HCV), human T-lymphotropic virus-1 (HTLV-1), and Merkel cell polyomavirus (MCPyV). The clinical phenotypes resulting from infection with these oncoviruses range from asymptomatic infection to invasive cancers. Patients with inborn errors of immunity (IEI) are prone to the development of infectious diseases caused by a narrow or broad spectrum of pathogens, including oncoviruses in some cases. Studies of patients with IEI have deepened our understanding of the non-redundant mechanisms underlying the control of EBV, HHV8 and HPV infections. The human genetic factors conferring predisposition to oncogenic HBV, HCV, HTLV-1 and MCPyV manifestations remain elusive. We briefly review here what is currently known about the IEI conferring predisposition to severe infection with oncoviruses.

Molecular Crosstalk between the Hepatitis C Virus and the Extracellular Matrix in Liver Fibrogenesis and Early Carcinogenesis

Simple Summary

In the era of direct-acting antivirals against the hepatitis C virus (HCV), curing chronic hepatitis C has become a reality. However, while replicating chronically, HCV creates a peculiar state of inflammation and oxidative stress in the infected liver, which fuels DNA damage at the onset of HCV-induced hepatocellular carcinoma (HCC). This cancer, the second leading cause of death by cancer, remains of bad prognosis when diagnosed. This review aims to decipher how HCV durably alters elements of the extracellular matrix that compose the liver microenvironment, directly through its viral proteins or indirectly through the induction of cytokine secretion, thereby leading to liver fibrosis, cirrhosis, and, ultimately, HCC.

Abstract

Chronic infection by the hepatitis C virus (HCV) is a major cause of liver diseases, predisposing to fibrosis and hepatocellular carcinoma. Liver fibrosis is characterized by an overly abundant accumulation of components of the hepatic extracellular matrix, such as collagen and elastin, with consequences on the properties of this microenvironment and cancer initiation and growth. This review will provide an update on mechanistic concepts of HCV-related liver fibrosis/cirrhosis and early stages of carcinogenesis, with a dissection of the molecular details of the crosstalk during disease progression between hepatocytes, the extracellular matrix, and hepatic stellate cells.

The Role of Endoglin in Hepatocellular Carcinoma

Endoglin (CD105) is a type-1 integral transmembrane glycoprotein and coreceptor for transforming growth factor-β (TGF-β) ligands. The endoglin/TGF-β signaling pathway regulates hemostasis, cell proliferation/migration, extracellular matrix (ECM) synthesis and angiogenesis. Angiogenesis contributes to early progression, invasion, postoperative recurrence, and metastasis in hepatocellular carcinoma (HCC), one of the most widespread malignancies globally. Endoglin is overexpressed in newly formed HCC microvessels. It increases microvessel density in cirrhotic and regenerative HCC nodules. In addition, circulating endoglin is present in HCC patients, suggesting potential for use as a diagnostic or prognostic factor. HCC angiogenesis is dynamic and endoglin expression varies by stage. TRC105 (carotuximab) is an antibody against endoglin, and three of its clinical trials were related to liver diseases. A partial response was achieved when combining TRC105 with sorafenib. Although antiangiogenic therapy still carries some risks, combination therapy with endoglin inhibitors or other targeted therapies holds promise.

Whole-Exome Sequencing in Patients Affected by Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis Reveals New Variants Potentially Contributing to the Phenotype

Background

Adverse drug reactions (ADRs) are frequent occurring events that can essentially be defined as harmful or unpleasant symptoms secondary to the use of a medicinal product. ADRs involve a wide spectrum of clinical manifestations ranging from minor itching and rash to life-threatening reactions. Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare ADRs. SJS-TEN may be considered a polygenic pathology due to additive/epistatic effects caused by sequence variants in numerous genes. Next-generation sequencing (NGS) represents a potentially interesting exploration tool in such scenario as it facilitates the simultaneous analysis of large genomic regions and genes at affordable cost.

Methods

The present study has involved using whole-exome sequencing (WES) for the first time on SJS-TEN patients. It involved robust and innovative multistep bioinformatics analysis focusing on 313 candidate genes potentially participating in the disease’s aetiology, specific drugs’ metabolism and gene regulation.

Results

We identified combinations of frequently occurring and rare variants that may contribute to the disease’s pathogenesis. Depending on the specific drug being taken, different variants (and alleles) in NAT2, CYP2D8, CYP2B6, ABCC2, UGT2B7 and TCF3 were identified as coherent candidates representing potential future markers for SJS-TEN.

Conclusion

The present study proposed and has described (for the first time) a large-scale genomic analysis of patients affected by SJS-TEN. The genes and variants identified represent relevant candidates potentially participating in the disease’s pathogenesis. Corroborating that proposed by others, we found that complex combinations of frequently occurring and rare variants participating in particular drug metabolism molecular cascades could be associated with the phenotype. TCF3 TF may be considered a coherent candidate for SJS-TEN that should be analysed in new cohorts of patients having ADRs.

Human genetics of HCV infection phenotypes in the era of direct-acting antivirals

The recent introduction of direct-acting antivirals (DAAs) has revolutionized hepatitis C virus (HCV) therapy by improving virus eradication rates to over 90% in most patient groups. However, the impact of DAAs on global disease burden is currently limited, and a large number of chronically infected individuals remain at risk of developing liver complications, such as liver cirrhosis and hepatocellular carcinoma (HCC). The identification of patients at risk of liver complications and a greater understanding of the biological mechanisms involved in HCV disease progression might improve disease control. Recent genome-wide association and exome sequencing studies have identified several host genetic variants influencing the progression of liver fibrosis and the development of HCC associated with HCV infection and are reviewed here. Interestingly, some of the genetic variants associated with those HCV-associated liver complications were also associated with the clinical course of non-viral chronic hepatitis. Future challenges include the incorporation of this genetic information into clinical risk models for personalized disease management and the study of emerging phenotypes such as liver fibrosis regression and HCC development after HCV eradication.