S-adenosyl-L-methionine (SAMe) halts the autoimmune response in patients with primary biliary cholangitis (PBC) via antioxidant and S-glutathionylation processes in cholangiocytes

The Amelioration of Methionine Restriction on the Celiac Toxic Effects of p31-43 Gliadin Peptide Is Disrupted by S-Adenosyl-Methionine

Methionine restriction (MR) has been found to alleviate the progression of diseases such as cognitive disorders and cancer, but it is not clear whether regulating methionine availability can have a beneficial effect on wheat gluten-induced celiac disease. We aimed to excavate the effects of MR on the celiac toxic effects of p31-43 gliadin peptide. In this study, we systematically investigated the effects of MR on p31-43 gliadin peptide-induced oxidative damage, the elevation of tissue transglutaminase enzyme activity, the overexpression of inflammatory factors, the increase of permeability, and T-lymphocyte dysfunction by utilizing Caco-2 epithelial cells and lymphocytes derived from mouse mesenteric lymph nodes to elucidate the effectiveness of MR. Moreover, the potential mechanism of MR on innate and adaptive immune regulation was explored with the help of S-adenosyl-methionine (SAM), a critical metabolic intermediate in methionine cycle. We discovered that MR effectively suppressed the celiac toxic effects of p31-43 gliadin peptide. Furthermore, we illustrated the controlling role of SAM in MR to regulate the toxic effects of gliadin in terms of both gliadin-induced innate and adaptive immune responses and found that SAM could directly affect the effectiveness of MR. This study might offer novel insights for the utilization of MR in celiac disease (such as MR interventions or gluten-free diets with specific methionine content) as well as the roles of SAM in MR.

Genetically predicted immune cells mediate the association between gut microbiota and autoimmune liver diseases

Background

Increasing evidence suggests an association between gut microbiota and Autoimmune Liver Diseases (AILDs). However, causal inference remains controversial due to confounding bias in observational studies. Additionally, there is currently no clear evidence indicating that immune cells act as intermediate phenotypes in the pathogenesis of AILDs. This study utilizes the Mendelian Randomization (MR) method to investigate the causal relationships among gut microbiota, immune cells, and AILDs.

Methods

Initially, we conducted a two-sample MR analysis to predict the causal relationships among 412 gut microbiota, 731 immune phenotypes, and AILDs. Subsequently, a series of sensitivity analyses were performed to validate the initial MR results and reverse MR analysis was conducted to exclude reverse causality. Finally, a two-step MR analysis was utilized to quantify the proportion of the impact of gut microbiota on AILDs mediated by immune cells.

Results

Following rigorous MR analysis, our findings indicate that increased involvement of the gut microbiome in the superpathway of L-tryptophan biosynthesis is positively associated with an elevated risk of Autoimmune Hepatitis (AIH). The effect is partially mediated by the CD14+ CD16+ monocyte Absolute Count, which accounts for 17.47% of the total effect. Moreover, the species Ruminococcus obeum appears to mediate the development of Primary Sclerosing Cholangitis (PSC) through CD62L-CD86+ myeloid Dendritic Cell %Dendritic Cell, contributing to 32.47% of the total observed effect.

Conclusion

Our study highlights the potential mediating mechanisms of immune cells in the causal relationship between the gut microbiome and AILDs. These insights provide a foundation for developing preventive strategies for AILDs in clinical practice.

Progress in the Management of Patients with Cholestatic Liver Disease: Where Are We and Where Are We Going?

Cholestatic liver disease is a group of diseases in which bile acid accumulates in the liver for various reasons, resulting in abnormal liver biochemical indicators and histological damage. Cholestasis can be divided into intrahepatic cholestasis and extrahepatic cholestasis, which will contribute to liver damage and progress to liver fibrosis and cirrhosis. Primary biliary cholangitis (PBC) and primary sclerosing cholangitis are the two most typical cholestatic liver diseases. Ursodeoxycholic acid is currently the first-line treatment for PBC, while obeticholic acid, budesonide and fibrates have also shown good potential in the treatment of PBC. There are currently no official drugs approved to treat primary sclerosing cholangitis, and the use of ursodeoxycholic acid may have certain clinical benefits. At present, progress has been made in new treatment directions for cholestatic liver disease, including fibroblast growth factor 19, cholestyramine, S-adenosyl-L-methionine, steroid drugs, farnesoid X receptor agonists, and more. Considerable progress has been made in the management of cholestatic liver disease but there are still many opportunities and challenges. In this review, we summarized the recommended guidelines for the management of cholestatic disease and the progress of new drug research and development, in order to provide an important reference for the clinical practice of cholestatic liver disease.

The Role of miRNA and Long Noncoding RNA in Cholestatic Liver Diseases

Cholestatic liver diseases encompass a range of organic damages, metabolic disorders, and dysfunctions within the hepatobiliary system, arising from various pathogenic causes. These factors contribute to disruptions in bile production, secretion, and excretion. Cholestatic liver diseases can be classified into intrahepatic and extrahepatic cholestasis, according to the location of occurrence. The etiology of cholestatic liver diseases is complex, and includes drugs, poisons, viruses, parasites, bacteria, autoimmune responses, tumors, and genetic metabolism. The pathogenesis of cholelstatic liver disease is not completely clarified, and effective therapy is lacking. Clarifying its mechanism to find more effective therapeutic targets and drugs is an unmet need. Increasing evidence demonstrates that miRNA and long noncoding RNA are involved in the progression of cholestatic liver diseases. This review provides a comprehensive summary of the research progress on the roles of miRNA and long noncoding RNA in cholestatic liver diseases. The aim of the review is to enhance the understanding of their potential diagnostic, therapeutic, and prognostic value for patients with cholestasis.

SAM protects against alveolar septal cell apoptosis in autoimmune emphysema rats

BACKGROUND

Hypomethylation of the perforin gene promoter in CD4 + T cells, inflammation and oxidative stress, might be involved in alveolar septal cell apoptosis associated with emphysema in rats. This study aimed to investigate the effects of S-adenosylmethionine (SAM) on this kind of apoptosis in rats with autoimmune emphysema.

METHODS

Twenty-four rats were randomly divided into three groups: a normal control group, a model group, and a SAM group. Pathological changes in lung tissues were observed, and the mean linear intercept (MLI) and mean alveolar number (MAN) were measured. The levels of anti-endothelial cell antibodies (AECA) in serum, alveolar septal cell apoptosis, perforin gene promotor methylation in CD4 + T cells in the spleen, and the levels of cytokines, malondialdehyde (MDA), and glutathione (GSH) and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in bronchoalveolar lavage fluid (BALF) were investigated.

RESULTS

The MLI, apoptosis index (AI) of alveolar septal cells, levels of AECA in serum, and levels of tumour necrosis factor-α (TNF-α), matrix metalloproteinase-9 (MMP-9) and MDA in BALF were increased, while the MAN, methylation levels, and the activities of GSH, SOD and GSH-Px in BALF were decreased in the model group compared with those in the normal control group and the SAM group (all P < 0.05). The levels of interleukin-8 (IL-8) in BALF were greater in the model group than in the normal control group (P < 0.05).

CONCLUSIONS

SAM protects against alveolar septal cell apoptosis, airway inflammation and oxidative stress in rats with autoimmune emphysema possibly by partly reversing the hypomethylation of the perforin gene promoter in CD4 + T cells.

Primary biliary cholangitis: molecular pathogenesis perspectives and therapeutic potential of natural products

Primary biliary cirrhosis (PBC) is a chronic cholestatic immune liver disease characterized by persistent cholestasis, interlobular bile duct damage, portal inflammation, liver fibrosis, eventual cirrhosis, and death. Existing clinical and animal studies have made a good progress in bile acid metabolism, intestinal flora disorder inflammatory response, bile duct cell damage, and autoimmune response mechanisms. However, the pathogenesis of PBC has not been clearly elucidated. We focus on the pathological mechanism and new drug research and development of PBC in clinical and laboratory in the recent 20 years, to discuss the latest understanding of the pathological mechanism, treatment options, and drug discovery of PBC. Current clinical treatment mode and symptomatic drug support obviously cannot meet the urgent demand of patients with PBC, especially for the patients who do not respond to the current treatment drugs. New treatment methods are urgently needed. Drug candidates targeting reported targets or signals of PBC are emerging, albeit with some success and some failure. Single-target drugs cannot achieve ideal clinical efficacy. Multitarget drugs are the trend of future research and development of PBC drugs.

Influence of Coronary Artery Bypass Grafts on Blood Aminothiols in Patients with Coronary Artery Disease

Coronary artery disease (CAD) and the coronary artery bypass graft (CABG) are associated with a decreased blood glutathione (bGSH) level. Since GSH metabolism is closely related to other aminothiols (homocysteine and cysteine) and glucose, the aim of this study was to reveal the associations of bGSH with glucose and plasma aminothiols in CAD patients (N = 35) before CABG and in the early postoperative period. Forty-three volunteers with no history of cardiovascular disease formed the control group. bGSH and its redox status were significantly lower in CAD patients at admission. CABG had no significant effect on these parameters, with the exception of an increase in the bGSH/hemoglobin ratio. At admission, CAD patients were characterized by negative associations of homocysteine and cysteine with bGSH. All these associations disappeared after CABG. An association was found between an increase in oxidized GSH in the blood in the postoperative period and fasting glucose levels. Thus, CAD is associated with the depletion of the intracellular pool and the redox status of bGSH, in which hyperhomocysteinemia and a decrease in the bioavailability of the extracellular pool of cysteine play a role. The present study indicates that CABG causes disruptions in aminothiol metabolism and induces the synthesis of bGSH. Moreover, glucose becomes an important factor in the dysregulation of GSH metabolism in CABG.

Primary Biliary Cholangitis: Promising Emerging Innovative Therapies and Their Impact on GLOBE Scores

Primary biliary cholangitis (PBC), previously referred to as primary biliary cirrhosis, is an autoimmune disorder leading to the destruction of intra-hepatic bile ducts. If untreated, progressive bile duct damage and cholestasis can lead to ductopenia and result in cirrhosis. Ursodiol, the first drug approved for PBC, has changed the natural history of this disease and improved patient outcomes. Subsequently, several new prediction models incorporating a response to ursodiol were developed. These include the GLOBE score, which was shown to predict long-term outcomes in patients with PBC. In 2016, obeticholic acid (OCA) became the second drug to be approved by the FDA, predominantly based on improvement in alkaline phosphatase (ALP) levels. This trial has subsequently influenced the design of clinical trials. Several drugs are currently being evaluated as therapeutic options for PBC, with improvement in ALP being a main endpoint. In this review, we will discuss the impact of new therapies on GLOBE scores in patients with PBC.

Benefit of glucosyl Hesperidin in patients with primary biliary cholangitis: A multicenter, open-label, randomized control study

INTRODUCTION

Globally, the number of patients with primary biliary cholangitis (PBC) is increasing. Growing evidence suggests that oxidative stress plays a significant role in the pathogenesis of chronic liver disease regardless of its etiology. Hesperidin, a natural antioxidative substance derived from citrus peel, has been shown to have an anti-inflammatory effect in a rat arthritis model and may be a potential substance to attenuate intrahepatic inflammation in patients with PBC. In this study, the potential of glucosyl hesperidin as a therapeutic agent for PBC will be investigated through antioxidative stress mechanisms.

METHODS

Patients with PBC who are 20 years or older will be eligible to participate. Patients will be assigned to 1 of 2 groups and given either 500 or 1000 mg of glucosyl hesperidin per day. The primary endpoint is the ratio of changes in serum gamma-glutamyl transferase levels before and after 24 weeks of glucosyl hesperidin administration. The secondary endpoints are serum hepatobiliary enzyme levels (alkaline phosphatase, transaminase, and total bilirubin levels) and the protein expression levels of nuclear factor erythroid 2-related factor 2 and its target molecule 8, 16, and 24 weeks after administration compared to before administration.

DISCUSSION

The prospective clinical interventional study was designed to assess the supportive effect of glucosyl hesperidin on hepatic function in patients with PBC receiving basic ursodeoxycholic acid treatment.

Role of Oxidative Stress in Liver Disorders

Oxygen is vital for life as it is required for many different enzymatic reactions involved in intermediate metabolism and xenobiotic biotransformation. Moreover, oxygen consumption in the electron transport chain of mitochondria is used to drive the synthesis of ATP to meet the energetic demands of cells. However, toxic free radicals are generated as byproducts of molecular oxygen consumption. Oxidative stress ensues not only when the production of reactive oxygen species (ROS) exceeds the endogenous antioxidant defense mechanism of cells, but it can also occur as a consequence of an unbalance between antioxidant strategies. Given the important role of hepatocytes in the biotransformation and metabolism of xenobiotics, ROS production represents a critical event in liver physiology, and increasing evidence suggests that oxidative stress contributes to the development of many liver diseases. The present review, which is part of the special issue “Oxidant stress in Liver Diseases”, aims to provide an overview of the sources and targets of ROS in different liver diseases and highlights the pivotal role of oxidative stress in cell death. In addition, current antioxidant therapies as treatment options for such disorders and their limitations for future trial design are discussed.

Primary Biliary Cholangitis and Primary Sclerosing Cholangitis: Current Knowledge of Pathogenesis and Therapeutics

Cholangiopathies encompass various biliary diseases affecting the biliary epithelium, resulting in cholestasis, inflammation, fibrosis, and ultimately liver cirrhosis. Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are the most important progressive cholangiopathies in adults. Much research has broadened the scope of disease biology to genetic risk, epigenetic changes, dysregulated mucosal immunity, altered biliary epithelial cell function, and dysbiosis, all of which interact and arise in the context of ill-defined environmental triggers. An in-depth understanding of the molecular pathogenesis of these cholestatic diseases will help clinicians better prevent and treat diseases. In this review, we focus on the main underlying mechanisms of disease initiation and progression, and novel targeted therapeutics beyond currently approved treatments.

DHEA Protects Human Cholangiocytes and Hepatocytes against Apoptosis and Oxidative Stress

Primary biliary cholangitis (PBC) is a rare chronic cholestatic and immune-mediated liver disease of unknown aetiology that targets intrahepatic bile duct cells (cholangiocytes) and primarily affects postmenopausal women, when their estrogen levels sharply decrease. An impaired cholangiocyte response to estrogen characterizes the terminal stage of the disease, as this is when an inefficiency of cholangiocyte proliferation, in balancing the loss of intrahepatic bile ducts, is observed. Here, we report that the estrogen precursor dehydroepiandrosterone (DHEA) and its sulfate metabolites, DHEA-S and 17 β-estradiol, enhance the proliferation of cholangiocytes and hepatocytes in vitro. Flow cytometry analysis showed that DHEA and DHEA-S decreased glyco-chenodeoxycholic acid (GCDC)-driven apoptosis in cholangiocytes. Cell viability assay (MTT) indicated that ER-α, -β, and the G-protein-coupled estrogen receptor, are involved in the protection of DHEA against oxidative stress in cholangiocytes. Finally, immunoblot analysis showed an elevated level of steroid sulfatase and a reduced level of sulfotransferase 1E1 enzymes, involved in the desulfation/sulfation process of estrogens in cirrhotic PBC, and primary sclerosis cholangitis (PSC) liver tissues, another type of chronic cholestatic and immune-mediated liver disease. Taken together, these results suggest that DHEA can prevent the deleterious effects of certain potentially toxic bile acids and reactive oxygen species, delaying the onset of liver disease.

Plasma S-Adenosylmethionine Is Associated with Lung Injury in COVID-19

Objective

S-Adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) are indicators of global transmethylation and may play an important role as markers of severity of COVID-19.

Methods

The levels of plasma SAM and SAH were determined in patients admitted with COVID-19 (n = 56, mean age = 61). Lung injury was identified by computed tomography (CT) in accordance with the CT0-4 classification.

Results

SAM was found to be a potential marker of lung damage risk in COVID-19 patients (SAM > 80 nM; CT3,4 vs. CT 0-2: relative ratio (RR) was 3.0; p = 0.0029). SAM/SAH > 6.0 was also found to be a marker of lung injury (CT2-4 vs. CT0,1: RR = 3.47, p = 0.0004). There was a negative association between SAM and glutathione level (ρ = −0.343, p = 0.011). Interleukin-6 (IL-6) levels were associated with SAM (ρ = 0.44, p = 0.01) and SAH (ρ = 0.534, p = 0.001) levels.

Conclusions

A high SAM level and high methylation index are associated with the risk of lung injury in patients with COVID-19. The association of SAM with IL-6 and glutathione indicates an important role of transmethylation in the development of cytokine imbalance and oxidative stress in patients with COVID-19.

Progress Identifying and Analyzing the Human Proteome: 2021 Metrics from the HUPO Human Proteome Project

The 2021 Metrics of the HUPO Human Proteome Project (HPP) show that protein expression has now been credibly detected (neXtProt PE1 level) for 18 357 (92.8%) of the 19 778 predicted proteins coded in the human genome, a gain of 483 since 2020 from reports throughout the world reanalyzed by the HPP. Conversely, the number of neXtProt PE2, PE3, and PE4 missing proteins has been reduced by 478 to 1421. This represents remarkable progress on the proteome parts list. The utilization of proteomics in a broad array of biological and clinical studies likewise continues to expand with many important findings and effective integration with other omics platforms. We present highlights from the Immunopeptidomics, Glycoproteomics, Infectious Disease, Cardiovascular, Musculo-Skeletal, Liver, and Cancers B/D-HPP teams and from the Knowledgebase, Mass Spectrometry, Antibody Profiling, and Pathology resource pillars, as well as ethical considerations important to the clinical utilization of proteomics and protein biomarkers.

Advances of natural activators for Nrf2 signaling pathway on cholestatic liver injury protection: a review

Cholestasis is a common manifestation of obstruction of bile flow in various liver diseases. If the bile acid accumulation is not treated in time, it will further lead to hepatocyte damage, liver fibrosis and ultimately to cirrhosis, which seriously affects human life. The pathogenesis of cholestatic liver injury is very complicated, mainly including oxidative stress and inflammation. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important transcription factor responsible for upregulating expression of various genes with cytoprotective functions. Nrf2 activation has been proved to inhibit oxidative stress and inflammatory reaction, modulate bile acid homeostasis, and alleviate fibrosis during cholestasis. Therefore, Nrf2 emerges as a potential therapeutic target for cholestatic liver injury. In recent years, natural products with various biological activities including anti-inflammatory, anti-oxidant, anti-tumor and anti-fibrotic effects have received growing attention for being hepatoprotective agents. Natural products like asiatic acid, diosmin, rutin, and so forth have shown significant potential in activating Nrf2 pathway which can lead to attenuate cholestatic liver injury. Therefore, this paper emphasizes the effect of Nrf2 signaling pathway on alleviating cholestasis, and summarizes recent evidence about natural Nrf2 activators with hepatoprotective effect in various models of cholestatic liver injury, thus providing theoretical reference for the development of anti-cholestatic drug.

p-STAT3 is a PDC-E2 interacting partner in human cholangiocytes and hepatocytes with potential pathobiological implications

The E2 component of the mitochondrial pyruvate dehydrogenase complex (PDC) is the key autoantigen in primary biliary cholangitis (PBC) and STAT3 is an inflammatory modulator that participates in the pathogenesis of many liver diseases. This study investigated whether PDC-E2 interacts with STAT3 in human cholangiocytes (NHC) and hepatocytes (Hep-G2) under cholestatic conditions induced by glyco-chenodeoxycholic acid (GCDC). GCDC induced PDC-E2 expression in the cytoplasmic and nuclear fraction of NHC, whereas in Hep-G2 cells PDC-E2 expression was induced only in the cytoplasmic fraction. GCDC-treatment stimulated phosphorylation of STAT3 in the cytoplasmic fraction of NHC. siRNA-mediated gene silencing of PDC-E2 reduced the expression of pY-STAT3 in NHC but not in HepG2 cells. Immunoprecipitation and a proximity ligation assay clearly demonstrated that GCDC enhanced pY-STAT3 binding to PDC-E2 in the nuclear and cytoplasmic fraction of NHC cells. Staining with Mitotracker revealed mitochondrial co-localization of PDC-E2/pS-STAT3 complexes in NHC and Hep-G2 cells. In cirrhotic PBC livers the higher expression of both PDC-E2 and pY-STAT3 was observed. The immunoblot analysis demonstrated the occurrence of double bands of PDC-E2 protein in control livers, which was associated with a lower expression of pY-STAT3. Our data indicate the interaction between PDC-E2 and phosphorylated STAT3 under cholestatic conditions, which may play a role in the development of PBC.