The balance between IL-17 and IL-22 produced by liver-infiltrating T-helper cells critically controls NASH development in mice

The Roles of T Cells in the Development of Metabolic Dysfunction-Associated Steatohepatitis

Metabolic dysfunction-associated steatohepatitis (MASH), the progressed period of metabolic dysfunction-associated steatotic liver disease (MASLD), is a multifaceted liver disease characterised by inflammation and fibrosis that develops from simple steatosis, even contributing to hepatocellular carcinoma and death. MASH involves several immune cell-mediated inflammation and fibrosis, where T cells play a crucial role through the release of pro-inflammatory cytokines and pro-fibrotic factors. This review discusses the complex role of various T cell subsets in the pathogenesis of MASH and highlights the progress of ongoing clinical trials involving T cell-targeted MASH therapies.

Navigating the Paradox of IL-22: Friend or Foe in Hepatic Health?

Interleukin-22 (IL-22), a cytokine from the IL-10 family produced by T cells and innate lymphoid cells, plays a crucial role in immune responses and tissue regeneration. Its association with liver disease has garnered significant attention; however, its exact impact remains controversial. This review aims to enhance the current understanding of the dual role of IL-22 in liver disease by exploring its protective and pathogenic effects. First, we provide an overview of IL-22 biology, including its source, receptors, and signaling pathways. Subsequently, we offer a comprehensive overview of the dual function of IL-22 in non-neoplastic liver disease, emphasizing its antiapoptotic and regenerative properties. We also discuss the applicability of the conclusions drawn from studies on nonalcoholic fatty liver disease to metabolic dysfunction-associated steatotic liver disease. Furthermore, we elaborate on the intricate role of IL-22 in hepatocellular carcinoma, particularly its influence on the tumor microenvironment, proliferation, and immune evasion. In conclusion, IL-22 is paradoxical in liver disease, acting as a friend and foe. It is imperative to understand this paradox to develop targeted therapies that capitalize on the beneficial effects of IL-22 while mitigating its detrimental effects.

Deficiency of β-arrestin2 ameliorates MASLD in mice by promoting the activation of TAK1/AMPK signaling

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a liver manifestation of metabolic syndrome characterized by excessive hepatic lipid accumulation and lipid metabolism disorders. It has become the most common chronic liver disease worldwide. β-arrestin2 is a multifunctional scaffold protein that is among the most important regulatory molecules, and it exerts key roles in regulating various cellular processes, such as immune response, cellular collagen production, and inflammation. In the current study, we aimed to explore the function of β-arrestin2 in the development and progression of MASLD. Firstly, we observed that the expression of β-arrestin2 was upregulated in liver samples from patients with MASLD. Then, the western diet (WD) combined with CCl4 injection-induced MASLD was established in wild-type mice, and showed that liver β-arrestin2 expression was also gradually increased, and positively correlated with the degree of lipid metabolism disorder during MASLD progression. Ulteriorly, β-arrestin2 knockout (Arrb2 KO) mice were utilized to induce the MASLD model and found that β-arrestin2 deficiency significantly ameliorated lipid accumulation and inflammatory response in the liver of MASLD mice. Furthermore, the in vitro depletion and overexpression experiments showed that increased β-arrestin2 aggravated lipid accumulation via inhibiting the activation of the TAK1/AMPK pathway, which may be mediated by competitively binding to TAB1 with TAK1. These findings suggest that β-arrestin2 is essential to regulate intrahepatic lipid metabolism. Here, we provide a novel insight in understanding of the expression and function of β-arrestin2 in MASLD, demonstrating that it may be a potential therapeutic target for MASLD treatment.

The microenvironment in the development of MASLD-MASH-HCC and associated therapeutic in MASH-HCC

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a series of obesity-related metabolic liver diseases, ranging from relatively benign hepatic steatosis to metabolic-associated steatohepatitis (MASH). With the changes in lifestyle, its incidence and prevalence have risen to epidemic proportions globally. In recent years, an increasing amount of evidence has indicated that the hepatic microenvironment is involved in the pathophysiological processes of MASH-induced liver fibrosis and the formation of hepatocellular carcinoma (HCC). The hepatic microenvironment is composed of various parenchymal and non-parenchymal cells, which communicate with each other through various factors. In this review, we focus on the changes in hepatocytes, cholangiocytes, liver sinusoidal endothelial cells (LSECs), hepatic stellate cells (HSCs), Kupffer cells (KC), dendritic cells (DC), neutrophils, monocytes, T and B lymphocytes, natural killer cells (NK), natural killer T cells (NKT), mucosal-associated invariant T cells (MAIT), γδT cells, and gut microbiota during the progression of MASLD. Furthermore, we discuss promising therapeutic strategies targeting the microenvironment of MASLD-MASH-HCC.

Immunotherapy and MASLD-Related HCC: Should We Reconsider the Role of Etiology in the Therapeutic Approach to HCC?

Hepatocellular carcinoma (HCC) accounts for 90% of primary liver cancers and typically arises in the context of chronic liver disease. With the increasing prevalence of metabolic disorders, metabolic dysfunction-associated steatotic liver disease (MASLD) has become the leading cause of chronic liver disease and the most rapidly increasing cause of HCC. The role of dysfunctional innate and adaptive immune responses in the development and progression of HCC is well-established, prompting numerous trials to evaluate the efficacy of immune checkpoint inhibitors (ICIs) in targeting tumor cells. These trials have yielded promising results, and ICIs, in combination with anti-vascular endothelial growth factor (VEGF) monoclonal antibodies, are now approved as first-line therapy for patients with metastatic or unresectable HCC, irrespective of the underlying liver disease. Notably, MASLD itself is characterized by immune system dysfunction, as metabolic inflammation plays a central role in its onset and progression. However, clinical studies and post-hoc analyses suggest that immunotherapy may be less effective in MASLD-associated HCC compared to viral-related HCC. This emerging evidence raises the question of whether the underlying liver disease influences the therapeutic response to ICIs in HCC. It may be time to consider tailoring therapeutic strategies for HCC based on the specific etiological, histological, and genotypical subgroups.

Examination of the causal role of immune cells in non-alcoholic fatty liver disease by a bidirectional Mendelian randomization study

Background

Non-alcoholic fatty liver disease (NAFLD) is a globally widespread disease. Recent investigations have highlighted a close association between immunity and NAFLD, but the causality between them has not been thoroughly examined.

Methods

A total of 731 immunological traits and NAFLD cohorts were derived from genome-wide association study summary data, and single nucleotide polymorphisms significantly associated with immune traits were identified as instrumental variables. Moreover, 731 phenotypes include absolute cell counts, median fluorescence intensity (MFI), morphological parameters, and relative cell counts. The bidirectional two-sample Mendelian randomization (MR) was performed primarily using the inverse-variance weighted methods, and sensitivity analysis was carried out simultaneously.

Results

Four immunophenotypes were identified to exert a protective effect against NAFLD, including HLA-DR+ CD4+ %lymphocytes, SSC-A on CD4+, CD24 MFI on IgD-CD38-, and CD8 MFI on CD28-CD8br. Seven immunophenotypes were identified to be hazardous, including CD28+ CD45RA+ CD8dim%CD8dim, CD127 MFI on CD28+ DN (CD4-CD8-), CD20 MFI on IgD+ CD38br, CD20 MFI on transitional, IgD MFI on transitional, CD3 MFI on central memory CD8br, and CD45 MFI on CD33brHLA-DR+ CD14-. However, reverse MR showed NAFLD had no causal effect on immunophenotypes.

Conclusion

The study demonstrated a potential causal link between several immunophenotypes and NAFLD, which contributes to advancing research and treatment of NAFLD based on immune-mediated mechanisms.

The role of the interleukin family in liver fibrosis

Liver fibrosis represents a wound-healing response to chronic liver injury caused by viral infections, alcohol, and chemicals agents. It is a critical step in the progression from chronic liver disease to cirrhosis and hepatocellular carcinoma. No chemical or biological drugs have been approved for the treatment of liver fibrosis. Relevant studies have demonstrated that effective inhibition of hepatitis B virus (HBV) replication by nucleoside (acid) analogs or polyethylene glycol alpha-interferon can lead to recovery in some patients with hepatitis B liver fibrosis, However, some patients with liver fibrosis do not show improvement, even after achieving a complete serologic and virologic response. A similar situation occurs in patients with hepatitis C-related liver fibrosis. The liver, with its unique anatomical and immunological structure, is the largest immune organ and produces a large number of cytokines in response to external stimuli, which are crucial for the progression of liver fibrosis. cytokines can act either by directly affecting hepatic stellate cells (HSCs) or by indirectly regulating immune target cells. Among these, the interleukin family activates a complex cascade of responses, including cytokines, chemokines, adhesion molecules, and lipid mediators, playing a key role in the initiation and regulation of inflammation, as well as innate and adaptive immunity. In this paper, we systematically summarize recent literature to elucidate the pathogenesis of interleukin-mediated liver fibrosis and explore potential therapeutic targets for liver fibrosis treatment.

Immunology and treatments of fatty liver disease

Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are two major chronic liver diseases worldwide. The triggers for fatty liver can be derived from external sources such as adipose tissue, the gut, personal diet, and genetics, or internal sources, including immune cell responses, lipotoxicity, hepatocyte death, mitochondrial dysfunction, and extracellular vesicles. However, their pathogenesis varies to some extent. This review summarizes various immune mechanisms and therapeutic targets associated with these two types of fatty liver disease. It describes the gut-liver axis and adipose tissue-liver crosstalk, as well as the roles of different immune cells (both innate and adaptive immune cells) in fatty liver disease. Additionally, mitochondrial dysfunction, extracellular vesicles, microRNAs (miRNAs), and gastrointestinal hormones are also related to the pathogenesis of fatty liver. Understanding the pathogenesis of fatty liver and corresponding therapeutic strategies provides a new perspective for developing novel treatments for fatty liver disease.

Harnessing IL-22 for metabolic health: promise and pitfalls

Primarily perceived as an anti-inflammatory and antimicrobial mediator in mucosa and skin, interleukin-22 (IL-22) has emerged as a pivotal metabolic regulator. Central to IL-22 signaling is its receptor, IL-22RA1. Through IL-22RA1, IL-22 orchestrates glucose homeostasis by modulating insulin secretion, reducing cellular stress in pancreatic islets, promoting beta-cell regeneration, and influencing hepatic glucose and lipid metabolism. These actions suggest its potential as a therapeutic for metabolic dysfunctions like diabetes, obesity, and steatohepatitis. However, clinical applications of IL-22 face challenges related to off-target effects and safety concerns. This review explores IL-22's physiological roles, regulatory mechanisms, and profound influence on metabolic tissues. It also underscores IL-22's dual role in metabolic health and disease, advocating further research to harness its therapeutic potential.

Modulating intestinal neuroimmune VIPergic signaling attenuates the reduction in ILC3-derived IL-22 and hepatic steatosis in MASLD

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD, formerly known as NAFLD) is a major driver of cirrhosis and liver-related mortality. However, therapeutic options for MASLD, including prevention of liver steatosis, are limited. We previously described that vasoactive intestinal peptide-producing neurons (VIP-neurons) regulate the efficiency of intestinal dietary fat absorption and IL-22 production by type 3 innate lymphoid cells (ILC3) in the intestine. Given the described hepatoprotective role of IL-22, we hypothesize that modulation of this neuroimmune circuit could potentially be an innovative approach for the control of liver steatosis.

METHODS

We used a model of diet-induced MASLD by exposing mice to a high-fat diet (HFD) for 16 weeks, when the development of liver steatosis was first observed in our animals. We characterized IL-22 production by intestinal ILC3 at this dietary endpoint. We then evaluated whether communication between VIP-neurons and ILC3 affected IL-22 production and MASLD development by exposing mice with a conditional genetic deletion of Vipr2 in ILC3 (Rorc(t)CreVipr2fl/fl) to the HFD. We also performed intermittent global inhibition of VIP-neurons using a chemogenetic inhibitory approach (VipIres-CrehM4DiLSL) in HFD-fed mice.

RESULTS

Production of IL-22 by intestinal ILC3 is reduced in steatotic mice that were exposed to an HFD for 16 weeks. Targeted deletion of VIP receptor 2 in ILC3 resulted in higher production of IL-22 in ILC3 and was associated with a significant reduction in liver steatosis in mice under HFD. Global inhibition of VIP-producing neurons also resulted in a significant reduction in liver steatosis.

CONCLUSIONS

Modulating VIPergic neuroimmune signaling can ameliorate the development of hepatic steatosis induced by a surplus of fat ingestion in the diet. This neuroimmune pathway should be further investigated as a potential therapeutic avenue in MASLD.

Interleukin-23 inhibitors decrease Fibrosis-4 index in psoriasis patients with elevated Fibrosis-4 index but not inteleukin-17 inhibitors

Recent studies indicate that hepatic diseases are associated with psoriasis. Non-invasive tests, including the Fibrosis-4 (FIB-4) index, which can confidently rule out the presence of advanced fibrosis, are currently receiving attention. However, data on the FIB-4 index in psoriasis patients and the effects of biologics on the FIB-4 index are limited. We investigated the relationships between the FIB-4 index and demographic or clinical characteristics as well as the effects of biologics on the FIB-4 index in psoriasis patients. Psoriasis patients aged 36-64 years, whose treatment was initiated with interleukin (IL)-17 inhibitors or IL-23 inhibitors for psoriasis from May 2015 to December 2022, were consecutively included. Data were collected retrospectively from the patients' charts. A total of 171 psoriasis patients were included in this study. Thirty-four, 43, 21, 32, and 41 psoriasis patients were treated with secukinumab, ixekizumab, brodalumab, guselkumab, or risankizumab, respectively. In biologics-naïve patients, a significant but weak positive correlation was observed between the FIB-4 index and age (r = 0.3246, p = 0.0018). There was no significant correlation between the FIB-4 index and other demographic or clinical characteristics. Regarding the effects of biologics on the FIB-4 index, no significant change was observed in psoriasis patients treated with any biologics. However, in psoriasis patients with a baseline FIB-4 index of >1.3, patients treated with guselkumab and those treated with either IL-23 inhibitor showed significantly decreased FIB-4 index scores 6 months after initiating the biologics (p = 0.0323, p = 0.0212). In contrast, no change was observed in FIB-4 index scores in patients treated with IL-17 inhibitors. In conclusion, our study revealed that the FIB-4 index was correlated with age in psoriasis patients. Furthermore, IL-23 inhibitors (but not IL-17 inhibitors) decreased the FIB-4 index score at 6 months in psoriasis patients with elevated FIB-4 index scores at baseline. Further studies are needed to clarify whether IL-23 inhibitors improve liver fibrosis physiologically and functionally.

Role of the type 3 cytokines IL-17 and IL-22 in modulating metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) comprises a spectrum of liver diseases that span simple steatosis, metabolic dysfunction-associated steatohepatitis (MASH) and fibrosis and may progress to cirrhosis and cancer. The pathogenesis of MASLD is multifactorial and is driven by environmental, genetic, metabolic and immune factors. This review will focus on the role of the type 3 cytokines IL-17 and IL-22 in MASLD pathogenesis and progression. IL-17 and IL-22 are produced by similar adaptive and innate immune cells such as Th17 and innate lymphoid cells, respectively. IL-17-related signaling is upregulated during MASLD resulting in increased chemokines and proinflammatory cytokines in the liver microenvironment, enhanced recruitment of myeloid cells and T cells leading to exacerbation of inflammation and liver disease progression. IL-17 may also act directly by activating hepatic stellate cells resulting in increased fibrosis. In contrast, IL-22 is a pleiotropic cytokine with a dominantly protective signature in MASLD and is currently being tested as a therapeutic strategy. IL-22 also exhibits beneficial metabolic effects and abrogates MASH-related inflammation and fibrosis development via inducing the production of anti-oxidants and anti-apoptotic factors. A sex-dependent effect has been attributed to both cytokines, most importantly to IL-22 in MASLD or related conditions. Altogether, IL-17 and IL-22 are key effectors in MASLD pathogenesis and progression. We will review the role of these two cytokines and cells that produce them in the development of MASLD, their interaction with host factors driving MASLD including sexual dimorphism, and their potential therapeutic benefits.

Immunobiotic Bacteria Attenuate Hepatic Fibrosis through the Modulation of Gut Microbiota and the Activation of Aryl-Hydrocarbon Receptors Pathway in Non-Alcoholic Steatohepatitis Mice

SCOPE

Nonalcoholic steatohepatitis (NASH) is a leading cause of chronic liver disease worldwide that can progress to liver fibrosis (LF). Probiotics have beneficial roles in reducing intestinal inflammation and gut-associated diseases, but their effects and mechanisms beyond the gut in attenuating the progression of LF are remained unclear.

METHODS AND RESULTS

In a mouse model of NASH/LF induced by a methionine-choline deficient (MCD) diet, immunobiotics are administered to investigate their therapeutic effects. Results show that the MCD diet leads to liver inflammation, steatosis, and fibrosis, which are alleviated by immunobiotics. Immunobiotics reduces serum endotoxin and inflammatory markers while increasing regulatory cytokines and liver weight. They also suppress Th17 cells, known for producing inflammatory cytokines. Furthermore, immunobiotics mitigate collagen deposition and fibrogenic signaling in the liver, while restoring gut-barrier integrity and microbiota composition. Additionally, immunobiotics enhance the activation of the aryl hydrocarbon receptor (AhR) pathway in both colonic and liver tissues.

CONCLUSIONS

Overall, these results demonstrate a novel insight into the mechanisms through which immunobiotic administration improves the gut health which in turn increases the AhR pathway and inhibits HSCs activation and fibrosis progression beyond the gut in the liver tissue of NASH/LF mice.

The Role of CD4+T Cells in Nonalcoholic Steatohepatitis and Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) has become the fourth leading cause of cancer-related deaths worldwide; annually, approximately 830,000 deaths related to liver cancer are diagnosed globally. Since early-stage HCC is clinically asymptomatic, traditional treatment modalities, including surgical ablation, are usually not applicable or result in recurrence. Immunotherapy, particularly immune checkpoint blockade (ICB), provides new hope for cancer therapy; however, immune evasion mechanisms counteract its efficiency. In addition to viral exposure and alcohol addiction, nonalcoholic steatohepatitis (NASH) has become a major cause of HCC. Owing to NASH-related aberrant T cell activation causing tissue damage that leads to impaired immune surveillance, NASH-associated HCC patients respond much less efficiently to ICB treatment than do patients with other etiologies. In addition, abnormal inflammation contributes to NASH progression and NASH-HCC transition, as well as to HCC immune evasion. Therefore, uncovering the detailed mechanism governing how NASH-associated immune cells contribute to NASH progression would benefit HCC prevention and improve HCC immunotherapy efficiency. In the following review, we focused our attention on summarizing the current knowledge of the role of CD4+T cells in NASH and HCC progression, and discuss potential therapeutic strategies involving the targeting of CD4+T cells for the treatment of NASH and HCC.

The roles of Th cells in myocardial infarction

Myocardial infarction, commonly known as a heart attack, is a serious condition caused by the abrupt stoppage of blood flow to a part of the heart, leading to tissue damage. A significant aspect of this condition is reperfusion injury, which occurs when blood flow is restored but exacerbates the damage. This review first addresses the role of the innate immune system, including neutrophils and macrophages, in the cascade of events leading to myocardial infarction and reperfusion injury. It then shifts focus to the critical involvement of CD4+ T helper cells in these processes. These cells, pivotal in regulating the immune response and tissue recovery, include various subpopulations such as Th1, Th2, Th9, Th17, and Th22, each playing a unique role in the pathophysiology of myocardial infarction and reperfusion injury. These subpopulations contribute to the injury process through diverse mechanisms, with cytokines such as IFN-γ and IL-4 influencing the balance between tissue repair and injury exacerbation. Understanding the interplay between the innate immune system and CD4+ T helper cells, along with their cytokines, is crucial for developing targeted therapies to mitigate myocardial infarction and reperfusion injury, ultimately improving outcomes for cardiac patients.

Implications of Microbiota and Immune System in Development and Progression of Metabolic Dysfunction-Associated Steatotic Liver Disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most prevalent type of liver disease worldwide. The exact pathophysiology behind MASLD remains unclear; however, it is thought that a combination of factors or "hits" act as precipitants for disease onset and progression. Abundant evidence supports the roles of diet, genes, metabolic dysregulation, and the intestinal microbiome in influencing the accumulation of lipids in hepatocytes and subsequent progression to inflammation and fibrosis. Currently, there is no cure for MASLD, but lifestyle changes have been the prevailing cornerstones of management. Research is now focusing on the intestinal microbiome as a potential therapeutic target for MASLD, with the spotlight shifting to probiotics, antibiotics, and fecal microbiota transplantation. In this review, we provide an overview of how intestinal microbiota interact with the immune system to contribute to the pathogenesis of MASLD and metabolic dysfunction-associated steatohepatitis (MASH). We also summarize key microbial taxa implicated in the disease and discuss evidence supporting microbial-targeted therapies in its management.

Prevalence and risk of nonalcoholic fatty liver disease among adult psoriatic patients: A systematic review, meta-analysis, and trial sequential analysis

BACKGROUND

This systematic review and meta-analysis aimed to report the evaluation of the prevalence and risk of nonalcoholic fatty liver disease (NAFLD) among adult psoriatic patients in a systematic review and meta-analysis.

METHODS

A comprehensive search was conducted across 4 databases of PubMed, Scopus, Cochrane Library, and Web of Science to collect relevant studies until November 30, 2023, without any restrictions for finding observational studies. The comprehensive meta-analysis version 3.0 software was used to calculate effect sizes, showing the event rate (ER), odds ratio (OR), and a 95% confidence interval (CI) to evaluate NAFLD risk or prevalence in psoriatic patients and controls or psoriatic patients alone. The quality scoring was performed by 1 author based on the Newcastle-Ottawa Scale tool. Publication bias, meta-regression analysis, and sensitivity analyses were performed. Additionally, Trial Sequential Analysis (TSA) was performed using TSA software.

RESULTS

A total of 581 records were identified among the databases and electronic sources. At last, 41 studies involving 607,781 individuals were included in the meta-analysis. The pooled ER of NAFLD among psoriatic patients was 29.5% (95%CI: 19.6%-41.7%) and I2 = 99.79%. The pooled OR of NAFLD in psoriatic patients compared to controls was 1.685 (95%CI: 1.382-2.055; P < .001) and I2 = 87.96%.

CONCLUSIONS

The study found a significant link between psoriasis and NAFLD, with psoriatic patients having a higher chance of developing NAFLD compared to the controls. The study calls for regular NAFLD screening in psoriatic patients to prevent liver complications.

The role of dendritic cells in MASH: friends or foes?

Dendritic cells (DCs) are major antigen-presenting cells that connect innate and adaptive immunity. Hepatic DCs are less activated and contribute to maintain the tolerogenic environment of the liver under steady state. Several studies indicated DCs in metabolic dysfunction-associated steatohepatitis (MASH), representing a substantial burden on healthcare systems due to its association with liver-related morbidity and mortality. Studies highlighted the potential disease-promoting role of liver DCs in the development of MASH while other experimental systems suggested their protective role. This review discusses this controversy and the current understanding of how DCs affect the pathogenesis of MASH.

The double roles of T cell-mediated immune response in the progression of MASLD

Metabolic dysfunction-associated steatotic liver disease(MASLD), formerly known as non-alcoholic fatty liver disease(NAFLD), has become a major cause of chronic liver disease and a significant risk factor for hepatocellular carcinoma, which poses a huge burden on global public health and economy. MASLD includes steatotic liver disease, steatohepatitis, and cirrhosis, and the latter two cause great harm to human health and life, even complicated with liver cancer. Immunologic mechanism plays a major role in promoting its development into hepatitis and cirrhosis. Now more and more evidences show that T cells play an important role in the progression of MASLD. In this review, we discuss the double roles of T cells in MASLD from the perspective of T cell response pathways, as well as new evidences regarding the possible application of immunomodulatory therapy in MASH.

Expression of immune related genes and possible regulatory mechanisms in different stages of non-alcoholic fatty liver disease

Background

Non-alcoholic fatty liver disease (NAFLD), which includes simple steatosis (SS) and non-alcoholic steatohepatitis (NASH), is a significant contributor to liver disease on a global scale. The change of immunity-related genes (IRGs) expression level leads to different immune infiltrations. However, the expression of IRGs and possible regulatory mechanisms involved in NAFLD remain unclear. The objective of our research is to investigate crucial genes linked to the development of NAFLD and the transition from SS to NASH.

Methods

Dataset GSE89632, which includes healthy controls, SS patients, and NASH patients, was obtained using the GEO database. To examine the correlation between sets of genes and clinical characteristics, we employed weighted gene co-expression network analysis (WGCNA) and differential expression analysis. Hub genes were extracted using a network of protein-protein interactions (PPI) and three different machine learning algorithms. To validate the findings, another dataset that is publicly accessible and mice that were subjected to a high-fat diet (HFD) or MCD diet were utilized. Furthermore, the ESTIMATE algorithm and ssGSEA were employed to investigate the immune landscape in the normal versus SS group and SS versus NASH group, additionally, the relationship between immune infiltration and the expression of hub genes was also examined.

Results

A total of 28 immune related key genes were selected. Most of these genes expressed reverse patterns in the initial and progressive stages of NAFLD. GO and KEGG analyses showed that they were focused on the cytokine related pathways and immune cell activation and chemotaxis. After screening by various algorithms, we obtained two hub genes, including JUN and CCL20. Validation of these findings was confirmed by analyzing gene expression patterns in both the validation dataset and the mouse model. Ultimately, two hub genes were discovered to have a significant correlation with the infiltration of immune cells.

Conclusion

We proposed that there were dynamic changes in the expression levels of IRGs in different stages of NAFLD disease, which led to different immune landscapes in SS and NASH. The findings of our research could serve as a guide for the accurate management of various phases of NAFLD.

Molecular mechanisms in MASLD/MASH-related HCC

Liver cancer is the third leading cause of cancer-related deaths and ranks as the sixth most prevalent cancer type globally. NAFLD or metabolic dysfunction-associated steatotic liver disease, and its more severe manifestation, NASH or metabolic dysfunction-associated steatohepatitis (MASH), pose a significant global health concern, affecting approximately 20%-25% of the population. The increased prevalence of metabolic dysfunction-associated steatotic liver disease and MASH is parallel to the increasing rates of obesity-associated metabolic diseases, including type 2 diabetes, insulin resistance, and fatty liver diseases. MASH can progress to MASH-related HCC (MASH-HCC) in about 2% of cases each year, influenced by various factors such as genetic mutations, carcinogen exposure, immune microenvironment, and microbiome. MASH-HCC exhibits distinct molecular and immune characteristics compared to other causes of HCC and affects both men and women equally. The management of early to intermediate-stage MASH-HCC typically involves surgery and locoregional therapies, while advanced HCC is treated with systemic therapies, including anti-angiogenic therapies and immune checkpoint inhibitors. In this comprehensive review, we consolidate previous research findings while also providing the most current insights into the intricate molecular processes underlying MASH-HCC development. We delve into MASH-HCC-associated genetic variations and somatic mutations, disease progression and research models, multiomics analysis, immunological and microenvironmental impacts, and discuss targeted/combined therapies to overcome immune evasion and the biomarkers to recognize treatment responders. By furthering our comprehension of the molecular mechanisms underlying MASH-HCC, our goal is to catalyze the advancement of more potent treatment strategies, ultimately leading to enhanced patient outcomes.

Pharmacologic inhibition of lipogenesis for the treatment of NAFLD

The hepatic accumulation of excess triglycerides is a seminal event in the initiation and progression of non-alcoholic fatty liver disease (NAFLD). Hepatic steatosis occurs when the hepatic accrual of fatty acids from the plasma and de novo lipogenesis (DNL) is no longer balanced by rates of fatty acid oxidation and secretion of very low-density lipoprotein-triglycerides. Accumulating data indicate that increased rates of DNL are central to the development of hepatic steatosis in NAFLD. Whereas the main drivers in NAFLD are transcriptional, owing to both hyperinsulinemia and hyperglycaemia, the effectors of DNL are a series of well-characterised enzymes. Several have proven amenable to pharmacologic inhibition or oligonucleotide-mediated knockdown, with lead compounds showing liver fat-lowering efficacy in phase II clinical trials. In humans with NAFLD, percent reductions in liver fat have closely mirrored percent inhibition of DNL, thereby affirming the critical contributions of DNL to NAFLD pathogenesis. The safety profiles of these compounds have so far been encouraging. It is anticipated that inhibitors of DNL, when administered alone or in combination with other therapeutic agents, will become important agents in the management of human NAFLD.

Liver fibrosis in NAFLD/NASH: from pathophysiology towards diagnostic and therapeutic strategies

Liver fibrosis, as an excess deposition of extracellular matrix (ECM) components, results from chronic liver injury as well as persistent activation of inflammatory response and of fibrogenesis. Liver fibrosis is a major determinant for chronic liver disease (CLD) progression and in the last two decades our understanding on the major molecular and cellular mechanisms underlying the fibrogenic progression of CLD has dramatically improved, boosting pre-clinical studies and clinical trials designed to find novel therapeutic approaches. From these studies several critical concepts have emerged, starting to reveal the complexity of the pro-fibrotic microenvironment which involves very complex, dynamic and interrelated interactions between different hepatic and extrahepatic cell populations. This review will offer first a recapitulation of established and novel pathophysiological basic principles and concepts by intentionally focus the attention on NAFLD/NASH, a metabolic-related form of CLD with a high impact on the general population and emerging as a leading cause of CLD worldwide. NAFLD/NASH-related pro-inflammatory and profibrogenic mechanisms will be analysed as well as novel information on cells, mediators and signalling pathways which have taken advantage from novel methodological approaches and techniques (single cell genomics, imaging mass cytometry, novel in vitro two- and three-dimensional models, etc.). We will next offer an overview on recent advancement in diagnostic and prognostic tools, including serum biomarkers and polygenic scores, to support the analysis of liver biopsies. Finally, this review will provide an analysis of current and emerging therapies for the treatment of NAFLD/NASH patients.

Distinct fibroblast functions associated with fibrotic and immune-mediated inflammatory diseases and their implications for therapeutic development

Fibroblasts are ubiquitous cells that can adopt many functional states. As tissue-resident sentinels, they respond to acute damage signals and shape the earliest events in fibrotic and immune-mediated inflammatory diseases. Upon sensing an insult, fibroblasts produce chemokines and growth factors to organize and support the response. Depending on the size and composition of the resulting infiltrate, these activated fibroblasts may also begin to contract or relax thus changing local stiffness within the tissue. These early events likely contribute to the divergent clinical manifestations of fibrotic and immune-mediated inflammatory diseases. Further, distinct changes to the cellular composition and signaling dialogue in these diseases drive progressive fibroblasts specialization. In fibrotic diseases, fibroblasts support the survival, activation and differentiation of myeloid cells, granulocytes and innate lymphocytes, and produce most of the pathogenic extracellular matrix proteins. Whereas, in immune-mediated inflammatory diseases, sequential accumulation of dendritic cells, T cells and B cells programs fibroblasts to support local, destructive adaptive immune responses. Fibroblast specialization has clear implications for the development of effective induction and maintenance therapies for patients with these clinically distinct diseases.

Pyruvate Oxidation Sustains B Cell Antigen-Specific Activation to Exacerbate MASH

B cells play a crucial role in the pathogenesis of metabolic dysfunction-associated steatohepatitis (MASH), a severe form of steatotic liver disease that if persistent can lead to cirrhosis, liver failure, and cancer. Chronic inflammation and fibrosis are key features of MASH that determine disease progression and outcomes. Recent advances have revealed that pathogenic B cell-derived cytokines and antibodies promote the development of MASH. However, the mechanisms through which B cells promote fibrosis and the metabolic adaptations underlying their pathogenic responses remain unclear. Here, we report that a subset of mature B cells with heightened cytokine responses accumulate in the liver and promote inflammation in MASH. To meet the increased energetic demand of effector responses, B cells increase their ATP production via oxidative phosphorylation (OXPHOS) fueled by pyruvate oxidation in a B cell receptor (BCR)-specific manner. Blocking pyruvate oxidation completely abrogated the inflammatory capacity of MASH B cells. Accordingly, the restriction of the BCR led to MASH attenuation, including reductions in steatosis, hepatic inflammation, and fibrosis. Mechanistically, BCR restriction decreased B cell maturation, activation, and effector responses in the liver, accompanied by decreased T cell- and macrophage-mediated inflammation. Notably, attenuated liver fibrosis in BCR-restricted mice was associated with lower IgG production and decreased expression of Fc-gamma receptors on hepatic stellate cells. Together, these findings indicate a key role for B cell antigen-specific responses in promoting steatosis, inflammation, and fibrosis during MASH.

The bidirectional immune crosstalk in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is an unabated risk factor for end-stage liver diseases with no available therapies. Dysregulated immune responses are critical culprits of MASLD pathogenesis. Independent contributions from either the innate or adaptive arms of the immune system or their unidirectional interplay are commonly studied in MASLD. However, the bidirectional communication between innate and adaptive immune systems and its impact on MASLD remain insufficiently understood. Given that both innate and adaptive immune cells are indispensable for the development and progression of inflammation in MASLD, elucidating pathogenic contributions stemming from the bidirectional interplay between these two arms holds potential for development of novel therapeutics for MASLD. Here, we review the immune cell types and bidirectional pathways that influence the pathogenesis of MASLD and highlight potential pharmacologic approaches to combat MASLD based on current knowledge of this bidirectional crosstalk.

NKG2D-mediated detection of metabolically stressed hepatocytes by innate-like T cells is essential for initiation of NASH and fibrosis

Metabolic-associated fatty liver disease (MAFLD) is a spectrum of clinical manifestations ranging from benign steatosis to cirrhosis. A key event in the pathophysiology of MAFLD is the development of nonalcoholic steatohepatitis (NASH), which can potentially lead to fibrosis and hepatocellular carcinoma, but the triggers of MAFLD-associated inflammation are not well understood. We have observed that lipid accumulation in hepatocytes induces expression of ligands specific to the activating immune receptor NKG2D. Tissue-resident innate-like T cells, most notably γδ T cells, are activated through NKG2D and secrete IL-17A. IL-17A licenses hepatocytes to produce chemokines that recruit proinflammatory cells into the liver, which causes NASH and fibrosis. NKG2D-deficient mice did not develop fibrosis in dietary models of NASH and had a decreased incidence of hepatic tumors. The frequency of IL-17A+ γδ T cells in the blood of patients with MAFLD correlated directly with liver pathology. Our findings identify a key molecular mechanism through which stressed hepatocytes trigger inflammation in the context of MAFLD.

Opportunities and challenges: interleukin-22 comprehensively regulates polycystic ovary syndrome from metabolic and immune aspects

Polycystic ovary syndrome (PCOS) is known as a prevalent but complicated gynecologic disease throughout the reproductive period. Typically, it is characterized by phenotypic manifestations of hyperandrogenism, polycystic ovary morphology, and persistent anovulation. For now, the therapeutic modality of PCOS is still a formidable challenge. Metabolic aberrations and immune challenge of chronic low-grade inflammatory state are significant in PCOS individuals. Recently, interleukin-22 (IL-22) has been shown to be therapeutically effective in immunological dysfunction and metabolic diseases, which suggests a role in the treatment of PCOS. In this review, we outline the potential mechanisms and limitations of IL-22 therapy in PCOS-related metabolic disorders including its regulation of insulin resistance, gut barrier, systemic inflammation, and hepatic steatosis to generate insights into developing novel strategies in clinical practice.

Vitamin A: too good to be bad?

Vitamin A is a micronutrient important for vision, cell growth, reproduction and immunity. Both deficiency and excess consuming of vitamin A cause severe health consequences. Although discovered as the first lipophilic vitamin already more than a century ago and the definition of precise biological roles of vitamin A in the setting of health and disease, there are still many unresolved issues related to that vitamin. Prototypically, the liver that plays a key role in the storage, metabolism and homeostasis of vitamin A critically responds to the vitamin A status. Acute and chronic excess vitamin A is associated with liver damage and fibrosis, while also hypovitaminosis A is associated with alterations in liver morphology and function. Hepatic stellate cells are the main storage site of vitamin A. These cells have multiple physiological roles from balancing retinol content of the body to mediating inflammatory responses in the liver. Strikingly, different animal disease models also respond to vitamin A statuses differently or even opposing. In this review, we discuss some of these controversial issues in understanding vitamin A biology. More studies of the interactions of vitamin A with animal genomes and epigenetic settings are anticipated in the future.

Vunakizumab-IL22, a Novel Fusion Protein, Promotes Intestinal Epithelial Repair and Protects against Gut Injury Induced by the Influenza Virus

Secondary immune damage to the intestinal mucosa due to an influenza virus infection has gained the attention of investigators. The protection of the intestinal barrier is an effective means of improving the survival rate in cases of severe pneumonia. We developed a fusion protein, Vunakizumab-IL22(vmab-IL22), by combining an anti-IL17A antibody with IL22. Our previous study showed that Vunakizumab-IL22 repairs the pulmonary epithelial barrier in influenza virus-infected mice. In this study, we investigated the protective effects against enteritis given its anti-inflammatory and tissue repair functions. The number of goblet cells and the expression of zonula occludens protein 1(ZO-1), Mucin-2, Ki67 and IL-22R were determined by immunohistochemistry (IHC) and quantitative RT-PCR in influenza A virus (H1N1)-infected mice. The expression of NOD-like receptor pyrin domain containing 3 (NLRP3) and toll- like-receptor-4 (TLR4) was assayed by IHC in the lungs and intestine in HIN1 virus-induced mice to evaluate the whole efficacy of the protective effects on lungs and intestines. Consequently, Cytochrome C, phosphorylation of nuclear factor NF-kappaB (p-NF-κB), IL-1β, NLRP3 and Caspase 3 were assayed by Western blotting in dextran sulfate sodium salt (DSS)-treated mice. Treatment with Vunakizumab-IL22 improved the shortened colon length, macroscopic and microscopic morphology of the small intestine (p < 0.001) significantly, and strengthened the tight junction proteins, which was accompanied with the upregulated expression of IL22R. Meanwhile, Vunakizumab-mIL22 inhibited the expression of inflammation-related protein in a mouse model of enteritis induced by H1N1 and DSS. These findings provide new evidence for the treatment strategy for severe viral pneumonia involved in gut barrier protection. The results suggest that Vunakizumab-IL22 is a promising biopharmaceutical drug and is a candidate for the treatment of direct and indirect intestinal injuries, including those induced by the influenza virus and DSS.

Psoriatic disease and non-alcoholic fatty liver disease shared pathogenesis review

Psoriatic disease (PD) and non-alcoholic fatty liver disease (NAFLD) potentially share disease pathways given the numerous inflammatory pathways involved in both diseases and a higher prevalence of NAFLD in PD patients.  Metabolic syndrome and obesity are a key link between the two diseases, but even when controlling for this, associations between both diseases are still seen. Therapeutics that impact metabolic or inflammatory pathways may be impactful in both PD and NAFLD. In this review, we describe common inflammatory pathways contributing to both PD and NAFLD and critically review the potential impact of treatments for and on both diseases.

Insights on drug and gene delivery systems in liver fibrosis

Complications of the liver are amongst the world's worst diseases. Liver fibrosis is the first stage of liver problems, while cirrhosis is the last stage, which can lead to death. The creation of effective anti-fibrotic drug delivery methods appears critical due to the liver's metabolic capacity for drugs and the presence of insurmountable physiological impediments in the way of targeting. Recent breakthroughs in anti-fibrotic agents have substantially assisted in fibrosis; nevertheless, the working mechanism of anti-fibrotic medications is not fully understood, and there is a need to design delivery systems that are well-understood and can aid in cirrhosis. Nanotechnology-based delivery systems are regarded to be effective but they have not been adequately researched for liver delivery. As a result, the capability of nanoparticles in hepatic delivery was explored. Another approach is targeted drug delivery, which can considerably improve efficacy if delivery systems are designed to target hepatic stellate cells (HSCs). We have addressed numerous delivery strategies that target HSCs, which can eventually aid in fibrosis. Recently genetics have proved to be useful, and methods for delivering genetic material to the target place have also been investigated where different techniques are depicted. To summarize, this review paper sheds light on the most recent breakthroughs in drug and gene-based nano and targeted delivery systems that have lately shown useful for the treatment of liver fibrosis and cirrhosis.

Immune cells and their derived microRNA-enriched extracellular vesicles in nonalcoholic fatty liver diseases: Novel therapeutic targets

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease worldwide. Despite extensive research and multiple clinical trials, there are still no FDA-approved therapies to treat the most severe forms of NAFLD. This is largely due to its complicated etiology and pathogenesis, which involves visceral obesity, insulin resistance, gut dysbiosis, etc. Although inflammation is generally believed to be one of the critical factors that drive the progression of simple steatosis to nonalcoholic steatohepatitis (NASH), the exact type of inflammation and how it contributes to NASH pathogenesis remain largely unknown. Liver inflammation is accompanied by the elevation of inflammatory mediators, including cytokines and chemokines and consequently intrahepatic infiltration of multiple types of immune cells. Recent studies revealed that extracellular vesicles (EVs) derived from inflammatory cells and hepatocytes play an important role in controlling liver inflammation during NASH. In this review, we highlight the roles of innate and adaptive immune cells and their microRNA-enriched EVs during NAFLD development and discuss potential drugs that target inflammatory pathways for the treatment of NAFLD.

Crohn's Disease Is Associated with Liver Fibrosis in Patients with Nonalcoholic Fatty Liver Disease

BACKGROUND

Chronic inflammation in IBD is postulated to drive NAFLD progression from steatosis to fibrosis.

AIMS

To study the histopathological spectrum of NAFLD in Crohn disease (CD) and Ulcerative colitis (UC).

METHODS

Patients with biopsy proven NAFLD at a quaternary center from 2008 to 2018 were included in this retrospective analysis. Inflammatory bowel disease (IBD) diagnosed either clinically and/or endoscopically at the time of liver biopsy. Multivariable regression and propensity score (PS) weighted analysis were conducted. Statistical analysis were performed using SAS statistical software.

RESULTS

Among 1009 patients with NAFLD a diagnosis of IBD was identified in 50 cases (34 CD and 16 UC). On multivariable analysis; CD was independently associated with significantly higher odds of advanced fibrosis (AF) on liver biopsy (adjusted OR = 4.09, 95% CI = 1.40-11.94) compared to NAFLD patients without IBD. Similar results were obtained with both the overlap PS weighted model (OR = 3.17, 95% CI = 1.55-6.49) and the PS matched model (OR = 3.49, 95% CI = 1.50-8.13).

CONCLUSION

In a large cohort of patients with histologically well characterized NAFLD, AF was more common in CD patients than NAFLD patients without IBD. These findings must be confirmed in a larger cohort, but suggest CD patients with NAFLD could be at greater risk for liver fibrosis.

Ongoing involvers and promising therapeutic targets of hepatic fibrosis: The hepatic immune microenvironment

Hepatic fibrosis is often secondary to chronic inflammatory liver injury. During the development of hepatic fibrosis, the damaged hepatocytes and activated hepatic stellate cells (HSCs) caused by the pathogenic injury could secrete a variety of cytokines and chemokines, which will chemotactic innate and adaptive immune cells of liver tissue and peripheral circulation infiltrating into the injury site, mediating the immune response against injury and promoting tissue reparation. However, the continuous release of persistent injurious stimulus-induced inflammatory cytokines will promote HSCs-mediated fibrous tissue hyperproliferation and excessive repair, which will cause hepatic fibrosis development and progression to cirrhosis even liver cancer. And the activated HSCs can secrete various cytokines and chemokines, which directly interact with immune cells and actively participate in liver disease progression. Therefore, analyzing the changes in local immune homeostasis caused by immune response under different pathological states will greatly enrich our understanding of liver diseases' reversal, chronicity, progression, and even deterioration of liver cancer. In this review, we summarized the critical components of the hepatic immune microenvironment (HIME), different sub-type immune cells, and their released cytokines, according to their effect on the development of progression of hepatic fibrosis. And we also reviewed and analyzed the specific changes and the related mechanisms of the immune microenvironment in different chronic liver diseases.Moreover, we retrospectively analyzed whether the progression of hepatic fibrosis could be alleviated by modulating the HIME.We aimed to elucidate the pathogenesis of hepatic fibrosis and provide the possibility for exploring the therapeutic targets for hepatic fibrosis.

The Essential Role of IL-17 as the Pathogenetic Link between Psoriasis and Metabolic-Associated Fatty Liver Disease

Interleukin 17 (IL-17) is an effector cytokine that plays a key role in the pathogenesis of both psoriasis and metabolic-associated fatty liver disease (MAFLD), a condition that is more prevalent and severe in patients with psoriasis. In liver inflammation, IL-17 is mainly produced by CD4+ T (TH17) and CD8+ T cells (Tc17), although numerous other cells (macrophages, natural killer cells, neutrophils and Tγδ cells) also contribute to the production of IL-17. In hepatocytes, IL-17 mediates systemic inflammation and the recruitment of inflammatory cells to the liver, and it is also implicated in the development of fibrosis and insulin resistance. IL-17 levels have been correlated with progression from MAFLD to steatohepatitis, cirrhosis, and even hepatocellular carcinoma. Clinical trials have shown that inhibiting IL-17A in patients with psoriasis could potentially contribute to the improvement of metabolic and liver parameters. A better understanding of the key factors involved in the pathogenesis of these chronic inflammatory processes could potentially lead to more efficient treatment for both psoriasis and MAFLD, and help to develop holistic strategies to improve the management of these patients.

Decoding the role of immune T cells: A new territory for improvement of metabolic-associated fatty liver disease

Metabolic-associated fatty liver disease (MAFLD) is a new emerging concept and is associated with metabolic dysfunction, generally replacing the name of nonalcoholic fatty liver disease (NAFLD) due to heterogeneous liver condition and inaccuracies in definition. The prevalence of MAFLD is rising by year due to dietary changes, metabolic disorders, and no approved therapy, affecting a quarter of the global population and representing a major economic problem that burdens healthcare systems. Currently, in addition to the common causative factors like insulin resistance, oxidative stress, and lipotoxicity, the role of immune cells, especially T cells, played in MAFLD is increasingly being emphasized by global scholars. Based on the diverse classification and pathophysiological effects of immune T cells, we comprehensively analyzed their bidirectional regulatory effects on the hepatic inflammatory microenvironment and MAFLD progression. This interaction between MAFLD and T cells was also associated with hepatic-intestinal immune crosstalk and gut microbiota homeostasis. Moreover, we pointed out several T-cell-based therapeutic approaches including but not limited to adoptive transfer of T cells, fecal microbiota transplantation, and drug therapy, especially for natural products and Chinese herbal prescriptions. Overall, this study contributes to a better understanding of the important role of T cells played in MAFLD progression and corresponding therapeutic options and provides a potential reference for further drug development.

Inflammatory processes involved in NASH-related hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related death worldwide. In the recent years nonalcoholic fatty liver disease (NAFLD) is becoming a growing cause of HCCs and the incidence of NAFLD-related HCCs is expected to further dramatically increase by the next decade. Chronic inflammation is regarded as the driving force of NAFLD progression and a key factor in hepatic carcinogenesis. Hepatic inflammation in NAFLD results from the persistent stimulation of innate immunity in response to hepatocellular injury and gut dysbiosis as well as by the activation of adaptive immunity. However, the relative roles of innate and adaptive immunity in the processes leading to HCC are still incompletely characterized. This is due to the complex interplay between different liver cell populations, which is also strongly influenced by gut-derived bacterial products, metabolic/nutritional signals. Furthermore, carcinogenic mechanisms in NAFLD/NASH appear to involve the activation of signals mediated by hypoxia inducible factors. This review discusses recent data regarding the contribution of different inflammatory cells to NAFLD-related HCC and their possible impact on patient response to current treatments.

The Development of Systemic Inflammatory Diseases in Hidradenitis Suppurativa

It is understood that the skin is a peripheral lymphoid tissue that defends against external environmental stimuli. Continuous activation from these factors, on the other hand, promotes persistent inflammation at the local location and, occasionally, tissue damage. Hidradenitis suppurativa (HS) is a typical inflammatory skin disease and becomes a source of numerous inflammatory cytokines due to the chronic intractable repeated inflamed tissues. Because inflammatory cells and cytokines circulate throughout the body from the inflamed organ, it has been hypothesized that HS-mediated skin inflammation impacts the systemic functioning of numerous organs. Recent updates to clinical and experimental investigations revealed that HS has a significant connection with systemic inflammatory disorders. We provide the details and comprehensive molecular mechanisms associated with systemic inflammatory illnesses due to HS.

Metabolic Associated Fatty Liver Disease as a Risk Factor for the Development of Central Nervous System Disorders

MAFLD/NAFLD is the most ordinary liver disease categorized by hepatic steatosis with the increase of surplus fat in the liver and metabolic liver dysfunction, which is associated with bigger mortality and a high medical burden. An association between MAFLD/NAFLD and central nervous system disorders including psychological disorders has been demonstrated. Additionally, MAFLD/NAFLD has been correlated with various types of neurodegenerative disorders such as amyotrophic lateral sclerosis or Parkinson’s disease. Contrasted to healthy controls, patients with MAFLD/NAFLD have a greater prevalence risk of extrahepatic complications within multiple organs. Dietary interventions have emerged as effective strategies for MAFLD/NAFLD. The PI3K/AKT/mTOR signaling pathway involved in the regulation of Th17/Treg balance might promote the pathogenesis of several diseases including MAFLD/NAFLD. As extrahepatic complications may happen across various organs including CNS, cooperative care with individual experts is also necessary for managing patients with MAFLD/NAFLD.

Treating inflammation to combat non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) with its more progressive form non-alcoholic steatohepatitis (NASH) has become the most common chronic liver disease, thereby representing a great burden for patients and healthcare systems. Specific pharmacological therapies for NAFLD are still missing. Inflammation is an important driver in the pathogenesis of NASH, and the mechanisms underlying inflammation in NAFLD represent possible therapeutic targets. In NASH, various intra- and extrahepatic triggers involved in the metabolic injury typically lead to the activation of different immune cells. This includes hepatic Kupffer cells, i.e. liver-resident macrophages, which can adopt an inflammatory phenotype and activate other immune cells by releasing inflammatory cytokines. As inflammation progresses, Kupffer cells are increasingly replaced by monocyte-derived macrophages with a distinct lipid-associated and scar-associated phenotype. Many other immune cells, including neutrophils, T lymphocytes - such as auto-aggressive cytotoxic as well as regulatory T cells - and innate lymphoid cells balance the progression and regression of inflammation and subsequent fibrosis. The detailed understanding of inflammatory cell subsets and their activation pathways prompted preclinical and clinical exploration of potential targets in NAFLD/NASH. These approaches to target inflammation in NASH include inhibition of immune cell recruitment via chemokine receptors (e.g. cenicriviroc), neutralization of CD44 or galectin-3 as well as agonism to nuclear factors like peroxisome proliferator-activated receptors and farnesoid X receptor that interfere with the activation of immune cells. As some of these approaches did not demonstrate convincing efficacy as monotherapies, a rational and personalized combination of therapeutic interventions may be needed for the near future.

Association between Porphyromonas Gingivalis and systemic diseases: Focus on T cells-mediated adaptive immunity

The association between periodontal disease and systemic disease has become a research hotspot. Porphyromonas gingivalis (P. gingivalis), a crucial periodontal pathogen, affects the development of systemic diseases. The pathogenicity of P. gingivalis is largely linked to interference with the host's immunity. This review aims to discover the role of P. gingivalis in the modulation of the host's adaptive immune system through a large number of virulence factors and the manipulation of cellular immunological responses (mainly mediated by T cells). These factors may affect the cause of large numbers of systemic diseases, such as atherosclerosis, hypertension, adverse pregnancy outcomes, inflammatory bowel disease, diabetes mellitus, non-alcoholic fatty liver disease, rheumatoid arthritis, and Alzheimer's disease. The point of view of adaptive immunity may provide a new idea for treating periodontitis and related systemic diseases.

Protein phosphatases regulate the liver microenvironment in the development of hepatocellular carcinoma

The liver is a complicated heterogeneous organ composed of different cells. Parenchymal cells called hepatocytes and various nonparenchymal cells, including immune cells and stromal cells, are distributed in liver lobules with hepatic architecture. They interact with each other to compose the liver microenvironment and determine its characteristics. Although the liver microenvironment maintains liver homeostasis and function under healthy conditions, it also shows proinflammatory and profibrogenic characteristics that can induce the progression of hepatitis and hepatic fibrosis, eventually changing to a protumoral microenvironment that contributes to the development of hepatocellular carcinoma (HCC). According to recent studies, phosphatases are involved in liver diseases and HCC development by regulating protein phosphorylation in intracellular signaling pathways and changing the activities and characteristics of liver cells. Therefore, this review aims to highlight the importance of protein phosphatases in HCC development and in the regulation of the cellular components in the liver microenvironment and to show their significance as therapeutic targets.

Polystyrene microplastics exacerbate experimental colitis in mice tightly associated with the occurrence of hepatic inflammation

The potential health effects of microplastics (MPs) have become a public concern due to their ubiquitousness in the environment and life. Numerous studies have demonstrated that a high dose of MPs can adversely affect gastrointestinal health. However, few studies have focused on the impact of microplastics on patients' health with respect to gastrointestinal diseases. Inflammatory bowel disease (IBD) has emerged as a global disease with a rapidly increasing incidence. IBD, a specific gastrointestinal illness characterized by acute, chronic inflammation and intestinal barrier dysfunction, might increase sensitivity to MPs exposure. Herein, we investigated the impact and mechanism of PS-MPs on dextran sodium sulfate (DSS)-induced colitis. The results demonstrated that gavage with PS-MPs alone caused minimal effects on the intestinal barrier and liver status of mice. For mice with colitis, additional PS-MPs exposure caused a shorter colon length, aggravated histopathological damage and inflammation, reduced mucus secretion, and increased the colon permeability. Furthermore, PS-MPs exposure also increased the risk of secondary liver injury associated with inflammatory cell infiltration. These findings provide more histopathological evidence and suggest a need for more research on the health risk of MPs for sensitive individuals.

Immune-metabolic interactions in homeostasis and the progression to NASH

The incidence of non-alcoholic fatty liver disease (NAFLD) has increased significantly over the past two decades. NAFLD ranges from simple steatosis (NAFL) to nonalcoholic steatohepatitis (NASH) and predisposes to fibrosis and hepatocellular carcinoma (HCC). The importance of the immune system in hepatic physiology and in the progression of NAFLD is increasingly recognized. At homeostasis, the liver participates in immune defense against pathogens and in tolerance of gut-derived microbial compounds. Hepatic immune cells also respond to metabolic stimuli and have a role in NAFLD progression to NASH. In this review, we discuss how metabolic perturbations affect immune cell phenotype and function in NAFL and NASH, and then focus on the role of immune cells in liver homeostasis and in the development of NASH.

The potential of mecciRNA in hepatic stellate cell to regulate progression of nonalcoholic hepatitis

BACKGROUND

Nonalcoholic steatohepatitis (NASH) occupies a substantial proportion of chronic liver disease worldwide, of which pathogenesis needs further research. Recent studies have demonstrated the significant roles of circular RNAs (circRNAs) in NASH, while the function of a novel type of circRNAs, namely mitochondria-encoded circRNAs (mecciRNAs), remains elusive. Therefore, we aimed to investigate their potential to regulate the progression of NASH in this study.

METHODS

GSE134146 was used to screen for differentially expressed mecciRNAs in NASH, while GSE46300 was used to identify NASH-related genes. To establish the mecciRNA-miRNA-mRNA networks, circMINE and miRNet databases were used for predicting downstream targets. Then, consensus clustering analysis was used to determine immune subtypes of NASH. Finally, we successfully validated our findings in vitro (LPS-treated hepatic stellate cells [HSCs]) and in vivo (MCD-diet mice) NASH models.

RESULTS

We confirmed that circRNomics balance is disrupted in HSCs of NASH, while two mecciRNAs (hsa_circ_0089761 and hsa_circ_0089763) could function as competing for endogenous RNAs (ceRNAs) to regulate fibrosis-related signals. Furthermore, we constructed two ceRNA networks based on mecciRNAs for the first time. Cell and animal NASH models validated our findings that c-MYC and SMAD2/3 were upregulated in HSCs, while THBS1 and p-STAT3 were upregulated in hepatocytes. Moreover, we identified 21 core genes by overlapping the differentially expressed genes (NASH vs. Normal) with mecciRNA-targeted genes. According to their expression profiles, NASH patients could be divided in 2 different clusters, in which proinflammatory signals (TNF and IL-17 pathways) are significantly activated in Cluster 1.

CONCLUSION

We successfully established two novel mecciRNA-miRNA-mRNA networks in HSCs and hepatocytes, which were further confirmed by in vitro and in vivo models. Meanwhile, the novel immunotyping model revealed the heterogeneity of NASH, thereby might guiding treatment options. Altogether, our study brought a distinct perspective on the relationship between mecciRNAs and NASH.

Pathogenesis from Inflammation to Cancer in NASH-Derived HCC

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and one of the deadliest cancers worldwide. As opposed to the majority of patients with HCC, approximately 20–30% of cases of non-alcoholic steatohepatitis (NASH)-derived HCC develop malignant tumours in the absence of liver cirrhosis. NASH is characterized by metabolic dysregulation, chronic inflammation and cell death in the liver, which provide a favorable setting for the transformation of inflammation into cancer. This review aims to describe the pathogenesis and the underlying mechanism of the transition from inflammation to cancer in NASH.

T cells and liver fibrosis

Liver fibrosis develops from the excessive deposition of extracellular matrix in the liver caused by chronic liver inflammation or various chronic injuries, and it eventually develops into liver cirrhosis. The process of liver fibrosis is closely related to the immune response, and increasing evidence reveals the role of T lymphocytes, including Th1, Th2, Th17, regulatory T cells, and mucosa‐associated invariant T cells, in liver fibrosis. These immune cells play antifibrotic or profibrotic roles during fibrosis, and the reversal of fibrosis by targeting immune cells has attracted widespread attention. Activation of hepatic stellate cells, which form the core of fibrosis, is regulated by various immune mediators, including various immune cells and their associated cytokines. Therefore, the mechanism of action elicited by each cell type must be further elucidated to provide a basis for the design of new therapeutic targets. The purpose of this review is to summarize the roles and mechanisms of T lymphocytes and their subsets in liver fibrosis and highlight the biomarkers and potential therapeutic targets associated with these cells.

Increased Secreted Frizzled-Related Protein 5 mRNA Expression in the Adipose Tissue of Women with Nonalcoholic Fatty Liver Disease Associated with Obesity

Secreted frizzled-related protein 5 (SFRP5) is an anti-inflammatory adipocytokine secreted by adipocytes that seems to be linked with nonalcoholic fatty liver disease (NAFLD). We aimed to evaluate the role of the SFRP5-wingless-MMTV integration site family member 5a (WNT5A) pathway, closely related to adipogenesis, in subcutaneous (SAT) and visceral adipose tissues (VAT) and its relationship with obesity-related NAFLD. Our cohort was composed of 60 women with morbid obesity (MO), who underwent hypocaloric diet, subclassified according to their hepatic histopathology and 15 women with normal weight. We observed increased SFRP5 mRNA expression in VAT and lower WNT5A expression in SAT in MO compared to normal weight. We found elevated SFRP5 expression in nonalcoholic steatohepatitis (NASH) in SAT and in mild simple steatosis (SS) and NASH in VAT. We observed higher WNT5A expression in SS compared to normal liver in SAT, and a peak of WNT5A expression in mild SS. To conclude, we reported increased SFRP5 mRNA expression in SAT and VAT of NAFLD-related to obesity subjects, suggesting an implication of the SFRP5-WNT5A pathway in NAFLD pathogenesis, probably due to the adipose tissue-liver axis. Since the mechanisms by which this potential interaction takes place remain elusive, more research in this field is needed.

Sex-Dependent Hepatoprotective Role of IL-22 Receptor Signaling in Non-Alcoholic Fatty Liver Disease-Related Fibrosis

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD) is a major health problem with complex pathogenesis. Although sex differences in NAFLD pathogenesis have been reported, the mechanisms underlying such differences remain understudied. Interleukin (IL)22 is a pleiotropic cytokine with both protective and/or pathogenic effects during liver injury. IL22 was shown to be hepatoprotective in NAFLD-related liver injury. However, these studies relied primarily on exogenous administration of IL22 and did not examine the sex-dependent effect of IL22. Here, we sought to characterize the role of endogenous IL22-receptor signaling during NAFLD-induced liver injury in males and females.

METHODS

We used immunofluorescence, flow cytometry, histopathologic assessment, and gene expression analysis to examine IL22 production and characterize the intrahepatic immune landscape in human subjects with NAFLD (n = 20; 11 men and 9 women) and in an in vivo Western high-fat diet-induced NAFLD model in IL22RA knock out mice and their wild-type littermates.

RESULTS

Examination of publicly available data sets from 2 cohorts with NAFLD showed increased hepatic IL22 gene expression in females compared with males. Furthermore, our immunofluorescence analysis of liver sections from NAFLD subjects (n = 20) showed increased infiltration of IL22-producing cells in females. Similarly, IL22-producing cells were increased in wild-type female mice with NAFLD and the hepatic IL22/IL22 binding protein messenger RNA ratio correlated with expression of anti-apoptosis genes. The lack of endogenous IL22-receptor signaling (IL22RA knockout) led to exacerbated liver damage, inflammation, apoptosis, and liver fibrosis in female, but not male, mice with NAFLD.

CONCLUSIONS

Our data suggest a sex-dependent hepatoprotective antiapoptotic effect of IL22-receptor signaling during NAFLD-related liver injury in females.