Immune Exhaustion of T Cells in Alveolar Echinococcosis Patients and Its Reversal by Blocking Checkpoint Receptor TIGIT in a Murine Model

Spatiotemporal Transcriptomic Profiling Reveals the Dynamic Immunological Landscape of Alveolar Echinococcosis

Alveolar echinococcosis (AE) is caused by the chronic infection of E. multilocularis, whose tumor-like growth can lead to high fatality if improperly treated. The early diagnosis of infection and the treatment of advanced AE remain challenging. Herein, bulk RNA-seq, scRNA-seq, and spatial transcriptomics technologies are integrated, to reveal the host immune response mechanism against E. multilocularis both spatially and chronologically, collecting mouse liver samples at multiple timepoints up to 15 months post infection. These results unveil an unprecedented high-resolution spatial atlas of the E. multilocularis infection foci and the functional roles of neutrophils, Spp1+ macrophages, and fibroblasts during disease progression. The heterogeneity of neutrophil and macrophage subpopulations are critical in both parasite-killing and the occurrence of immunosuppression during AE progression. These findings indicate the transition of parasite control strategy from "active killing" to "negative segregation" by the host, providing instructive insights into the treatment strategy for echinococcosis.

The genetic variation of mitochondrial sequences and pathological differences of Echinococcus multilocularis strains from different continents

Alveolar echinococcosis is a lethal zoonotic disease caused by the fox tapeworm Echinococcus multilocularis. The parasite is widely distributed in the Northern Hemisphere and exhibits low genetic diversity among populations. To compare the differences among four E. multilocularis strains from different geographical locations, namely, Alaska (EM-AK), Japan (EM-JP), Xinjiang (EM-XJ), and Ningxia (EM-NX), their complete mitochondrial (mt) sequences were compared, and their induced pathological lesions were analyzed in mouse models. The complete mt sequence of EM-AK resulted in 0.84%-0.86% variation as compared with the other strains, which had a lower variation. Phylogenetic analysis and parsimony network indicated that EM-AK resulted in 30,000 years of evolutionary distance from the other three strains. EM-AK induced more pathological damage than the other three strains, which was likely to induce more host cell infiltration and acute granuloma in the liver. More importantly, EM-AK produced more protoscoleces than the other three strains, which may impact the transmission dynamics of the parasite. Given the geographical location of four strains, which is far from each other, and also the pathological differences, the strains of E. multilocularis are likely models for addressing the relationship and interfacial immune response between the host and the helminth.IMPORTANCEEchinococcus multilocularis is the causative agent of alveolar echinococcosis, which is considered the most serious parasitic disease in the Northern Hemisphere. There are many genotypes, but the pathogenic and mitochondria sequence and differences are still unclear. Therefore, this study showed both pathological and genetic differences between the four strains of E. multilocularis. EM-AK induced more severe immune responses and especially induced more host cell infiltration, which resulted in more severe granuloma in the liver. EM-JP has metacestode lesions morphologically closer to those of E. granulosus with clear cyst fluid. However, this strain produced much fewer protoscoleces (PSCs). Genetically, EM-AK is more distant from other strains.

GHSR gene knockout alleviates the liver pathological response in Echinococcus granulosus infection by reducing parasite survival

Cystic echinococcosis (CE) is a parasitic disease caused by the larval stage of Echinococcus granulosus, and the immunosuppressive microenvironment exacerbates disease progression. Ghrelin, a peptide hormone, plays a role in modulating immune inflammation and may influence the progression of E. granulosus infection through its receptor, GHSR (growth hormone secretagogue receptor). However, whether GHSR downregulation can inhibit E. granulosus infection remains unclear. In this study, we extracted liver tissues from E. granulosus-infected mice and those treated with the GHSR antagonist [D-Lys3]-GHRP-6. Proteomic analysis revealed 341 differentially expressed proteins, of which 185 were upregulated and 156 were downregulated. Metabolomic sequencing revealed 101 differentially expressed metabolites, including 62 upregulated and 39 downregulated metabolites. KEGG pathway enrichment analysis of both proteomic and metabolomic data revealed seven key signalling pathways, 11 key proteins, and 26 key metabolites that interact through metabolic and organic system networks. Next, we examined the disease progression of E. granulosus infection in GHSR-knockout mice. Compared with the E. granulosus (Eg) group, the GHSR-KO group presented a significant reduction in the number of liver infection foci. The serum and liver ghrelin levels were significantly greater in the E. granulosus group than in the control group, along with increased secretion of proinflammatory cytokines (IL-2 and IFN-γ) and decreased secretion of anti-inflammatory cytokines (IL-4 and IL-10). In contrast, the GHSR-KO group presented significantly lower ghrelin levels in both the serum and liver, with reduced proinflammatory cytokine secretion and increased anti-inflammatory cytokine secretion, similar to those of the control group. Furthermore, ghrelin and inflammation-related factors, including MyD88, NF-κB p65, iNOS, and Arg-1, exhibited coordinated expression changes in liver lesions and surrounding areas. These findings suggest that GHSR gene knockout can ameliorate the progression of liver E. granulosus infection and associated liver inflammation.

Immunological landscape of hepatic alveolar echinococcosis: A bibliometric analysis

BACKGROUND

Hepatic alveolar echinococcosis (HAE) is a chronic parasitic disease caused by the larval stage of Echinococcus multilocularis. Although significant research has been conducted on the pathogenesis and immunological aspects of HAE, comprehensive bibliometric analyses in this area are still lacking. This study sought to fill this gap by systematically analyzing the immunological literature on HAE using bibliometric methods.

AIM

To identify research trends, key contributors, and emerging developments and offer insights to guide future research in this field.

METHODS

Research articles on HAE published between 1983 and 2023 were retrieved from the Web of Science Core Collection database. A total of 319 articles were selected for bibliometric analysis, which was conducted using the CiteSpace and VOSviewer software. The analysis focused on key variables such as publication volume, authors, journals, countries, references, and keywords.

RESULTS

The analysis revealed a significant increase in research on HAE over the past four decades, particularly after 1995. China and Switzerland emerged as the leading countries in terms of publication volume, with Bruno Gottstein and Vuitton DA identified as the most influential authors in this field. Key research areas include the interaction between the pathogen and the host immune system, as well as advances in disease diagnosis and treatment strategies. The keyword co-occurrence analysis highlighted the primary themes and identified emerging trends within the research landscape.

CONCLUSION

This study provides a comprehensive framework for understanding HAE immunology and highlights research hotspots, future directions, key contributors, and the importance of international cooperation.

Inhibition of the MyD88 signaling pathway could upregulates Ghrelin expression to synergistically regulate hepatic Echinococcus multilocularis-infected progression

Introduction

AE and whether the inhibition of the MyD88 inflammatory pathway can enhance Ghrelin expression to collaboratively modulate AE progression remains unclear.

Methods

In this study, we evaluated Ghrelin serum levels and changes in TLR4/MyD88/NF-κB pathway proteins and inflammatory factors in AE patients and E. multilocularis mouse models at different stages of infection (-4, -8, and -12 weeks). Additionally, we administered the MyD88 inhibitor TJ-M2010-5 intraperitoneally to infected mice to evaluate alterations in inflammation and Ghrelin levels, as well as disease progression.

Results

A decrease in serum Ghrelin levels in AE patients, whereas both Ghrelin and GHSR, along with TLR4/MyD88/NF-κB pathway proteins and markers of M1/M2 macrophage polarization, exhibited increased expression in the inflammatory cell zones surrounding hepatic lesions. Similar findings were observed in E. multilocularis-infected mice. M1-type inflammatory expression predominated throughout the infection's progression, with sustained high levels of Ghrelin counteracting inflammation. The TLR4/ MyD88/NF-κB pathway remained suppressed during the first 8 weeks, becoming activated only at 12 weeks. Inhibition of the MyD88 pathway resulted in reduced inflammation levels and upregulated Ghrelin expression, thereby collaboratively regulating the progression of hepatic infection.

Conclusion

These findings suggest an interactive regulation between the MyD88 inflammatory signaling pathway and Ghrelin, indicating that MyD88 inhibition could enhance Ghrelin expression to modulate the progression of E. multilocularis infection.

Upregulation of CD244 promotes CD8+ T cell exhaustion in patients with alveolar echinococcosis and a murine model

BACKGROUND

In patients with alveolar echinococcosis (AE), CD8+ T cells undergo functional exhaustion, which accelerates the malignant progression of AE. However, the role of inhibitory receptor CD244 in mediating CD8+ T cell exhaustion remains elusive.

METHODS

CD244 expression on exhausted CD8+ T cells in the close liver tissue (CLT) of AE patients was analyzed using single-cell RNA sequencing data. Immunohistochemistry and immunofluorescence were employed to detect CD244 expression. Flow cytometry was used to assess the impact of CD244 on differentiation and effector function of CD8+ T cells in patients with AE, in vitro and in vivo models. Reactive oxygen species (ROS) and oxygen consumption rate (OCR) were measured to evaluate the influence of CD244 on mitochondrial function of CD8+ T cells.

RESULTS

CD244+CD8+ T cells in the CLT of AE patients exhibit a more terminal differentiation phenotype, with reduced secretion of IFN-γ and TNF-α. In vitro studies revealed that CD8+ T cells from CD244-deficient mice produced higher levels of IFN-γ, TNF-α and Granzyme B. In vivo studies revealed that CD244 deficiency enhanced the secretion capacity of IFN-γ and TNF-α by CD8+ T cells, inhibiting the growth of metacestodes. Moreover, CD244 deficiency leads to a decrease in ROS levels in liver CD8+ T cells, while significantly increasing their adenosine triphosphate (ATP)-linked oxygen consumption rate.

CONCLUSIONS

CD244 facilitates AE disease progression by mediating immune exhaustion in CD8+ T cells.

High PD-1 and CTLA-4 expression correlates with host immune suppression in patients and a mouse model infected with Echinococcus multilocularis

BACKGROUND

Alveolar echinococcosis (AE), a fatal disease caused by Echinococcus multilocularis, often affects the liver, with tumor-like growth. However, the mechanism by which E. multilocularis evades host immune surveillance remains unclear.

METHODS

We collected liver specimens from hepatic alveolar echinococcosis (HAE) patients and established a mouse model of E. multilocularis infection. Immunofluorescence staining and flow cytometry were performed to analyze programmed cell death protein 1 (PD-1) and cytotoxic T lymphocyte associated antigen 4 (CTLA-4) expression in human samples, while flow cytometry and quantitative real-time polymerase chain reaction (PCR) were performed for similar analyses in mouse samples. Cell proliferation and protoscolex (PSC) killing assays were designed to explore how E. multilocularis induces host immunosuppression.

RESULTS

An inflammatory reaction band with high PD-1 and CTLA-4 expression was found in close liver tissue (CLT). The ratio of regulatory T cells (Tregs) was higher in CLT than in distant liver tissue (DLT), and Tregs in CLT tended to express higher levels of PD-1 and CTLA-4 than those in DLT from HAE patients. Echinococcus multilocularis-infected mice showed significantly elevated expression of PD-1 and CTLA-4 on splenocytes and peritoneal cells. PD-1/PD-L1 or CTLA-4 pathway blockade could relieve the immunosuppressive effects of Tregs from infected mice and enhance PSC killing by mouse splenocytes.

CONCLUSIONS

E. multilocularis regulated the function of T cells via the PD-1/PD-L1- and CTLA-4-dependent pathways and subsequently evaded host immune attacks. These findings provide insights for investigating the pathogenic mechanism of AE.

Ghrelin is involved in regulating the progression of Echinococcus Granulosus-infected liver lesions through suppression of immunoinflammation and fibrosis

BACKGROUND

Cystic Echinococcosis (CE) is a zoonotic disease causing fibrosis and necrosis of diseased livers caused by infection with Echinococcus granulosus (E.g). There is evidence that E.g is susceptible to immune escape and tolerance when host expression of immunoinflammation and fibrosis is suppressed, accelerating the progression of CE. Ghrelin has the effect of suppressing immunoinflammation and fibrosis, and whether it is involved in regulating the progression of E.g-infected liver lesions is not clear.

METHODS

Serum and hepatic Ghrelin levels were observed in E.g-infected mice (4, 12 and 36 weeks) and compared with healthy control groups. Co-localization analysis is performed between protein expression of Ghrelin in and around the hepatic lesions of E.g-infected 12-week mice and protein expression of different hepatic histiocytes by mIHC. HepG2 cells and protoscoleces (PSCs) protein were co-cultured in vitro, as well as PSCs were alone in vitro, followed by exogenously administered of Ghrelin and its receptor blocker, [D-Lys3]-GHRP-6, to assess their regulatory effects on immunoinflammation, fibrosis and survival rate of PSCs.

RESULTS

Serum Ghrelin levels were increased in E.g-infected 4- and 12-week mice, and reduced in 36-week mice. E.g-infected mice consistently recruited Ghrelin in and around the hepatic lesions, which was extremely strongly co-localized with the protein expression of hepatic stellate cells (HSCs), T cells and the TGF-β1/Smad3 pathway. The secretion of Ghrelin was increased with increasing concentrations of PSCs protein in HepG2 cells culture medium. Moreover, Ghrelin could significantly inhibit the secretion of IL-2, INF-γ and TNF-α, as well as the expression of Myd88/NF-κB and TGF-β1/Smad3 pathway protein, and promoted the secretion of IL-4 and IL-10. Blocking Ghrelin receptor could significantly inhibit PSCs growth in in vitro experiment.

CONCLUSION

Ghrelin is highly expressed in the early stages of hepatic E.g infection and may be involved in regulating the progression of liver lesions by suppression immunoinflammation and fibrosis.

Association of IL-9 Cytokines with Hepatic Injury in Echinococcus granulosus Infection

Cystic echinococcosis (CE) is a zoonotic disease caused by the parasite Echinococcus granulosus (E. granulosus), which can lead to the formation of liver lesions. Research indicates that E. granulosus releases both Toll-like receptor 2 (TLR2) and Interleukin-9 (IL-9), which can potentially impair the body's innate immune defenses and compromise the liver's ability to fight against diseases. To investigate the role of TLR2 and IL-9 in liver damage caused by E. granulosus infection, samples were initially collected from individuals diagnosed with CE. Subsequently, BALB/c mice were infected with E. granulosus at multiple time points (4 weeks, 12 weeks, 32 weeks) and the expression levels of these markers was then assessed at each of these phases. Furthermore, a BALB/c mouse model was generated and administered anti-IL-9 antibody via intraperitoneal injection. The subsequent analysis focused on the TLR2/MyD88/NF-κB signaling pathway and the expression of IL-9 in E. granulosus was examined. A co-culture experiment was conducted using mouse mononuclear macrophage cells (RAW264.7) and hepatic stellate cells (HSCs) in the presence of E. granulosus Protein (EgP). The findings indicated elevated levels of IL-9 and TLR2 in patients with CE, with the activation of the signaling pathway significantly increased as the duration of infection progressed. Administration of anti-IL-9 in mice reduced the activation of the TLR2/MyD88/NF-κB signaling pathway, exacerbating liver injury. Moreover, EgP stimulates the TLR2/MyD88/NF-κB signaling pathway, resulting in the synthesis of α-SMA and Collagen I. The data suggest that infection with E. granulosus may stimulate the production of IL-9 through the activation of the TLR2/MyD88/NF-κB signaling pathway, which is mediated by TLR2. This activation stimulates RAW264.7 and HSCs, exacerbating liver injury and fibrosis.

Targeting myeloid-derived suppressor cells promotes antiparasitic T-cell immunity and enhances the efficacy of PD-1 blockade (15 words)

Immune exhaustion corresponds to a loss of effector function of T cells that associates with cancer or chronic infection. Here, our objective was to decipher the mechanisms involved in the immune suppression of myeloid-derived suppressor cells (MDSCs) and to explore the potential to target these cells for immunotherapy to enhance checkpoint blockade efficacy in a chronic parasite infection. We demonstrated that programmed cell-death-1 (PD-1) expression was significantly upregulated and associated with T-cell dysfunction in advanced alveolar echinococcosis (AE) patients and in Echinococcus multilocularis-infected mice. PD-1 blockade ex vivo failed to reverse AE patients' peripheral blood T-cell dysfunction. PD-1/PD-L1 blockade or PD-1 deficiency had no significant effects on metacestode in mouse model. This was due to the inhibitory capacities of immunosuppressive granulocytic MDSCs (G-MDSCs), especially in the liver surrounding the parasite pseudotumor. MDSCs suppressed T-cell function in vitro in an indoleamine 2, 3 dioxygenase 1 (IDO1)-dependent manner. Although depleting MDSCs alone restored T-cell effector functions and led to some limitation of disease progression in E. multilocularis-infected mice, combination with PD-1 blockade was better to induce antiparasitic efficacy. Our findings provide preclinical evidence in support of targeting MDSC or combining such an approach with checkpoint blockade in patients with advanced AE. (200 words).

sCD155 as a potential marker for diagnosing the vascular invasion in hepatic alveolar echinococcosis

BACKGROUND

Alveolar Echinococcosis (AE) is a malignant zoonotic disease caused by Echinococcus multilocularis infection. Considering whether the lesion is accompanied by vascular invasion (VI) is crucial for treatment strategies. A cost-effective and convenient clinical diagnostic method is urgently needed to supplement current techniques. Consequently, we detected soluble CD155 (sCD155) as a potential biomarker for diagnosing VI in hepatic alveolar echinococcosis (HAE).

METHODS

Blood samples were from 42 AE patients and 49 healthy controls (HCs). Based on the computed tomography (CT) and contrast-enhanced CT, AE patients were further categorized into HAE with VI (VIAE; 27 cases) and HAE without VI (NVAE; 15 cases). The sCD155 concentration was measured by an enzyme-linked immunosorbent assay (ELISA). Correlations between sCD155 expression levels and clinicopathological features of AE patients were analyzed using SPSS and GraphPad Prism software.

RESULTS

The sCD155 concentrations in AE patients were significantly higher than in HCs. The serum sCD155 level significantly differed between the VIAE and NVAE groups. The univariate analysis showed that VI of AE was significantly correlated with the sCD155 level when the sCD155 was greater than 11 ng/mL. After adjusting for potential confounding factors, the multivariable analysis showed that sCD155 had an independent effect on VI of HAE. The receiver operating characteristic (ROC) curve showed that sCD155 could differentially diagnose VI of HAE at the cut-off value of 11.08 ng/mL with an area under the curve (AUC) value of 0.75. The sensitivity and specificity were 74.07 % and 66.67 %, respectively; the positive and negative predictive values were 74.07 % and 60.00 %, respectively.

CONCLUSION

The sCD155 could be a VI biomarker for HAE. Elevated sCD155 levels are indicative of an increased likelihood of concomitant VI in HAE patients, necessitating a thorough evaluation of vascular impairment and the formulation of individualized management strategies.

Immunological Characteristics of Hepatic Dendritic Cells in Patients and Mouse Model with Liver Echinococcus multilocularis Infection

The cestode Echinococcus multilocularis, which mainly dwells in the liver, leads to a serious parasitic liver disease called alveolar echinococcosis (AE). Despite the increased attention drawn to the immunosuppressive microenvironment formed by hepatic AE tissue, the immunological characteristics of hepatic dendritic cells (DCs) in the AE liver microenvironment have not been fully elucidated. Here, we profiled the immunophenotypic characteristics of hepatic DC subsets in both clinical AE patients and a mouse model. Single-cell RNA sequencing (scRNA-Seq) analysis of four AE patient specimens revealed that greater DC numbers were present within perilesional liver tissues and that the distributions of cDC and pDC subsets in the liver and periphery were different. cDCs highly expressed the costimulatory molecule CD86, the immune checkpoint molecule CD244, LAG3, CTLA4, and the checkpoint ligand CD48, while pDCs expressed these genes at low frequencies. Flow cytometric analysis of hepatic DC subsets in an E. multilocularis infection mouse model demonstrated that the number of cDCs significantly increased after parasite infection, and a tolerogenic phenotype characterized by a decrease in CD40 and CD80 expression levels was observed at an early stage, whereas an activated phenotype characterized by an increase in CD86 expression levels was observed at a late stage. Moreover, the expression profiles of major immune checkpoint molecules (CD244 and LAG3) and ligands (CD48) on hepatic DC subsets in a mouse model exhibited the same pattern as those in AE patients. Notably, the cDC and pDC subsets in the E. multilocularis infection group exhibited higher expression levels of PD-L1 and CD155 than those in the control group, suggesting the potential of these subsets to impair T cell function. These findings may provide valuable information for investigating the role of hepatic DC subsets in the AE microenvironment and guiding DC targeting treatments for AE.

Metabolic dysfunction-associated fatty liver disease/metabolic dysfunction-associated steatotic liver disease: general provisions

The literature review deals with the problem of metabolic dysfunction-associated fatty liver disease that is poorly studied in pediatric gastroenterology. Until recently, primary hepatic steatosis not associated with alcohol intake was defined as non-alcoholic fatty liver disease. Given the unity of the pathogenetic mechanisms underlying primary steatosis, associated steatohepatitis, liver fibrosis with metabolic disorders, such as visceral obesity, insulin resistance, meta-inflammation of adipose tissue, it was proposed to change the terminology. The authors present data on modern nomenclature definitions, etiological factors, prevalence, criteria of metabolic disorders and meta-inflammation associated with this nosology and specific to childhood. Metabolic dysfunction-associated fatty liver disease and nonalcoholic fatty liver disease are characterized by the development of hepatosteatosis. However, a distinguishing feature of metabolic dysfunction-associated fatty liver disease is the presence of metabolic disorders in a patient. It is believed that the use of the term “metabolic dysfunction-associated fatty liver disease” in clinical practice allows doctors to make a diagnosis more reliably and more accurately modify the patient’s lifestyle. Much attention is paid to the description of the heterogeneity of metabolic dysfunction-associated fatty liver disease in clinical practice, and a concise list of therapeutic options for metabolic dysfunction-associated fatty liver disease in childhood is presented.

The expression of CTLA-4 in hepatic alveolar echinococcosis patients and blocking CTLA-4 to reverse T cell exhaustion in Echinococcus multilocularis-infected mice

Alveolar echinococcosis (AE) is a zoonotic parasitic disease caused by the infection of Echinococcus multilocularis (E. multilocularis) larvae. Cytotoxic T-lymphocyte antigen 4 (CTLA-4) produces inhibitory signals and induces T cell exhaustion, thereby inhibiting the parasiticidal efficacy of the liver immune system. Therefore, the purpose of this study is to explore how T-cell exhaustion contributes to AE and whether blocking CTLA-4 could reverse T cell exhaustion. Here we discovered that the expression of CTLA-4 was increased in the infiltrating margin around the lesion of the liver from AE patients by using western blot and immunohistochemistry assay. Multiple fluorescence immunohistochemistry identified that CTLA-4 and CD4/CD8 molecules were co-localized. For in vitro experiments, it was found that the sustained stimulation of E. multilocularis antigen could induce T cell exhaustion, blocking CTLA-4-reversed T cell exhaustion. For in vivo experiments, the expression of CTLA-4 was increased in the liver of E. multilocularis-infected mice, and the CTLA-4 and CD4/CD8 molecules were co-localized. Flow cytometry analysis demonstrated that the percentages of both CD4+ T cells and CD8+ T cells in the liver and peripheral blood were significantly increased and induced T exhaustion. When the mice were treated with anti-CTLA-4 antibodies, the number and weight of the lesions decreased significantly. Meanwhile, the flow cytometry results suggested that blocking CTLA-4 could effectively reverse T cell exhaustion and reactivate immune function. Our work reveals that blocking CTLA-4 could effectively reverse the T cell exhaustion caused by E. multilocularis and could be used as a novel target for the treatment of AE.

Phenotype and function of MAIT cells in patients with alveolar echinococcosis

Mucosal-associated invariant T (MAIT) cells are a subpopulation of unconventional T cells widely involved in chronic liver diseases. However, the potential role and regulating factors of MAIT cells in alveolar echinococcosis (AE), a zoonotic parasitic disease by Echinococcus multilocularis (E. multilocularis) larvae chronically parasitizing liver organs, has not yet been studied. Blood samples (n=29) and liver specimens (n=10) from AE patients were enrolled. The frequency, phenotype, and function of MAIT cells in peripheral blood and liver tissues of AE patients were detected by flow cytometry. The morphology and fibrosis of liver tissue were examined by histopathology and immunohistochemistry. The correlation between peripheral MAIT cell frequency and serologic markers was assessed by collecting clinicopathologic characteristics of AE patients. And the effect of in vitro stimulation with E. multilocularis antigen (Emp) on MAIT cells. In this study, MAIT cells are decreased in peripheral blood and increased in the close-to-lesion liver tissues, especially in areas of fibrosis. Circulating MAIT exhibited activation and exhaustion phenotypes, and intrahepatic MAIT cells showed increased activation phenotypes with increased IFN-γ and IL-17A, and high expression of CXCR5 chemokine receptor. Furthermore, the frequency of circulating MAIT cells was correlated with the size of the lesions and liver function in patients with AE. After excision of the lesion site, circulating MAIT cells returned to normal levels, and the serum cytokines IL-8, IL-12, and IL-18, associated with MAIT cell activation and apoptosis, were altered. Our results demonstrate the status of MAIT cell distribution, functional phenotype, and migration in peripheral blood and tissues of AE patients, highlighting their potential as biomarkers and therapeutic targets.

Ghrelin regulating liver activity and its potential effects on liver fibrosis and Echinococcosis

Ghrelin widely exists in the central nervous system and peripheral organs, and has biological activities such as maintaining energy homeostasis, regulating lipid metabolism, cell proliferation, immune response, gastrointestinal physiological activities, cognition, memory, circadian rhythm and reward effects. In many benign liver diseases, it may play a hepatoprotective role against steatosis, chronic inflammation, oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress and apoptosis, and improve liver cell autophagy and immune response to improve disease progression. However, the role of Ghrelin in liver Echinococcosis is currently unclear. This review systematically summarizes the molecular mechanisms by which Ghrelin regulates liver growth metabolism, immune-inflammation, fibrogenesis, proliferation and apoptosis, as well as its protective effects in liver fibrosis diseases, and further proposes the role of Ghrelin in liver Echinococcosis infection. During the infectious process, it may promote the parasitism and survival of parasites on the host by improving the immune-inflammatory microenvironment and fibrosis state, thereby accelerating disease progression. However, there is currently a lack of targeted in vitro and in vivo experimental evidence for this viewpoint.

Upregulation of LAG3 modulates the immune imbalance of CD4+ T-cell subsets and exacerbates disease progression in patients with alveolar echinococcosis and a mouse model

Infection with the cestode Echinococcus multilocularis (E. multilocularis) causes alveolar echinococcosis (AE), a tumor-like disease predominantly affecting the liver but able to spread to any organ. T cells develop functional defects during chronic E. multilocularis infection, mostly due to upregulation of inhibitory receptors such as T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domains (TIGIT) and programmed death-1 (PD-1). However, the role of lymphocyte activation gene-3 (LAG3), an inhibitory receptor, in AE infection remains to be determined. Here, we discovered that high expression of LAG3 was mainly found in CD4+ T cells and induced regulatory T cells (iTregs) in close liver tissue (CLT) from AE patients. In a mouse model of E. multilocularis infection, LAG3 expression was predominantly found in T helper 2 (Th2) and Treg subsets, which secreted significantly more IL-4 and IL-10, resulting in host immune tolerance and disease progression at a late stage. Furthermore, LAG3 deficiency was found to drive the development of effector memory CD4+ T cells and enhance the type 1 CD4+ T-cell immune response, thus inhibiting metacestode growth in vivo. In addition, CD4+ T cells from LAG3-deficient mice produced more IFN-γ and less IL-4 when stimulated by E. multilocularis protoscoleces (EmP) antigen in vitro. Finally, adoptive transfer experiments showed that LAG3-knockout (KO) CD4+ T cells were more likely to develop into Th1 cells and less likely to develop into Tregs in recipient mice. Our work reveals that high expression of LAG3 accelerates AE disease progression by modulating the immune imbalance of CD4+ T-cell subsets. These findings may provide a novel immunotherapeutic strategy against E. multilocularis infection.

Dynamic changes in TIGIT expression on the T-cell surface and TIGIT-mediated T-cell dysfunction in the brains of mice with chronic Toxoplasma gondii infection

The immunosuppressive receptor TIGIT plays a vital role in the regulation of the immune system's response to pathogens. However, the expression pattern of this receptor in mouse brains during infection with Toxoplasma gondii cysts is not known. Here, we provide evidence of immunological changes and TIGIT expression in infected mouse brains through flow cytometry and QPCR. The obtained results show that TIGIT expression on brain T cells rose considerably after infection. T. gondii infection triggered the conversion of TIGIT+ TCM cells to TIGIT+ TEM cells and reduced their cytotoxicity. During the whole period of T. gondii infection, high intensity and persistent expression of IFN-γ and TNF-α in brain and serum of mice. This study shows that chronic T. gondii infection increases TIGIT expression on brain T cells and affects their immune function.

NOTCH signaling inhibition after DAPT treatment exacerbates alveolar echinococcosis hepatic fibrosis by blocking M1 and enhancing M2 polarization

Alveolar echinococcosis (AE) is a lethal helminthic liver disease caused by persistent infection with Echinococcus multilocularis (E. multilocularis). Although more and more attention has been paid to the macrophages in E. multilocularis infection, the mechanism of macrophage polarization, a critical player in liver immunity, is seldom studied. NOTCH signaling is involved in cell survival and macrophage-mediated inflammation, but the role of NOTCH signaling in AE has been equally elusive. In this study, liver tissue samples from AE patients were collected and an E. multilocularis infected mouse model with or without blocking NOTCH signaling was established to analyze the NOTCH signaling, fibrotic and inflammatory response of the liver after E. multilocularis infection. Changes in polarization and origin of hepatic macrophages were analyzed by flow cytometry. In vitro qRT-PCR and Western blot assays were performed to analyze key receptors and ligands in NOTCH signaling. Our data demonstrated that hepatic fibrosis develops after AE, and the overall blockade of NOTCH signaling caused by DAPT treatment exacerbates the levels of hepatic fibrosis and alters the polarization and origin of hepatic macrophages. Blocking NOTCH signaling in macrophages after E. multilocularis infection downregulates M1 and upregulates M2 expression. The downregulation of NTCH3 and DLL-3 in the NOTCH signaling pathway is significant. Therefore, NOTCH3/DLL3 may be the key pathway in NOTCH signaling regulating macrophage polarization affecting fibrosis caused by AE.

TIGIT blockade enhances tumor response to radiotherapy via a CD103 + dendritic cell-dependent mechanism

Blockade of the T cell immunoreceptor with the immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) can enhance innate and adaptive tumor immunity and radiotherapy (RT) can enhance anti-tumor immunity. However, our data suggest that TIGIT-mediated immune suppression may be an impediment to such goals. Herein, we report on the synergistic effects of RT combined with anti-TIGIT therapy and the mechanism of their interaction. Treatment efficacy was assessed by measuring primary and secondary tumor growth, survival, and immune memory capacity. The function of CD103 + dendritic cells (DCs) under the combined treatment was assessed in wild-type and BATF3-deficient (BATF3^-/-) mice. FMS-like tyrosine kinase 3 ligand (Flt3L) was used to confirm the role of CD103 + DCs in RT combined with anti-TIGIT therapy. TIGIT was upregulated in immune cells following RT in both esophageal squamous cell carcinoma patients and mouse models. Administration of the anti-TIGIT antibody enhanced the efficacy of RT through a CD8 + T cell-dependent mechanism. It was observed that RT and the anti-TIGIT antibody synergistically enhanced the accumulation of tumor-infiltrating DCs, which activated CD8 + T cells. The efficacy of the combination therapy was negated in the BATF3^-/- mouse model. CD103 + DCs were required to promote the anti-tumor effects of combination therapy. Additionally, Flt3L therapy enhanced tumor response to RT combined with TIGIT blockade. Our study demonstrated TIGIT blockade can synergistically enhance anti-tumor T cell responses to RT via CD8 + T cells (dependent on CD103 + DCs), suggesting the clinical potential of targeting the TIGIT pathway and expanding CD103 + DCs in RT.

Single-Cell Heterogeneity of the Liver-Infiltrating Lymphocytes in Individuals with Chronic Echinococcus multilocularis Infection

Human alveolar echinococcosis (AE) is a tumor-like disease predominantly located in the liver. The cellular composition and heterogeneity of the lesion-infiltrating lymphocytes which produce an "immunosuppressive" microenvironment are poorly understood. Here, we profiled 83,921 CD45+ lymphocytes isolated from the peripheral blood (PB), perilesion (PL), and adjacent normal (AN) liver tissue of four advanced-stage AE patients using single-cell RNA and T-cell receptor (TCR) sequencing technology. We identified 23 large clusters, and the distributions and transcriptomes of these cell clusters in the liver and periphery were different. The cellular proportions of exhausted CD8+ T cells and group 2 innate lymphoid cells (ILC2s) were notably higher in PL tissue, and the expression features of these cell subsets were related to neoplasm metastasis and immune response suppression. In the 5 CD8+ T-cell populations, only CD8+ mucosa-associated invariant T (MAIT) cells were enriched in PL samples and the TRAV1-2_TRAJ33_TRAC TCR was clonally expanded. In the 11 subsets of CD4+ T cells, Th17 cells and induced regulatory T cells (iTregs) were preferentially enriched in PL samples, and their highly expressed genes were related to cell invasion, tumor metastasis, and inhibition of the inflammatory immune response. Exhaustion-specific genes (TIGIT, PD-1, and CTLA4) were upregulated in Tregs. Interestingly, there was a close contact between CD8+ T cells and iTregs or Th17 cells, especially for genes related to immunosuppression, such as PDCD1-FAM3C, which were highly expressed in PL tissue. This transcriptional data set provides valuable insights and a rich resource for deeply understanding the immune microenvironment in AE, which could provide potential target signatures for AE diagnosis and immunotherapies.

Indoleamine 2,3-dioxygenase 1 signaling orchestrates immune tolerance in Echinococcus multilocularis-infected mice

The cestode Echinococcus multilocularis larva infection causes lethal zoonotic alveolar echinococcosis (AE), a disease posing a great threat to the public health worldwide. This persistent hepatic tumor-like disease in AE patients has been largely attributed to aberrant T cell responses, of which Th1 responses are impeded, whilst Th2 and regulatory T cell responses are elevated, creating an immune tolerogenic microenvironment in the liver. However, the immune tolerance mechanisms are not fully understood. Dendritic cells (DCs) are key cellular components in facilitating immune tolerance in chronic diseases, including AE. Here, we demonstrate that indoleamine 2,3-dioxygenase 1-deficient (IDO1-/-) mice display less severe AE as compared to wild-type (WT) mice during the infection. Mechanistically, IDO1 prevents optimal T cells responses by programming DCs into a tolerogenic state. Specifically, IDO1 prevents the maturation and migration potential of DCs, as shown by the significantly enhanced expression of the antigen-presenting molecule (MHC II), costimulatory molecules (CD80 and CD86), and chemokine receptors (CXCR4 and CCR7) in infected IDO1-/- mice as compared to infected wild-type mice. More importantly, the tolerogenic phenotype of DCs is partly reverted in IDO1-/- mice, as indicated by enhanced activation, proliferation, and differentiation of both CD4+ and CD8+ - T cells upon infection with Echinococcus multilocularis, in comparison with WT mice. Interestingly, in absence of IDO1, CD4+ T cells are prone to differentiate to effector memory cells (CD44+CD62L-); in contrast, CD8+ T cells are highly biased to the central memory phenotype (CD44+CD62L+). Overall, these data are the first to demonstrate the essential role of IDO1 signaling in inducing immunosuppression in mice infected with Echinococcus multilocularis.

Echinococcus granulosus: The establishment of the metacestode in the liver is associated with control of the CD4+ T-cell-mediated immune response in patients with cystic echinococcosis and a mouse model

The larval stage of the tapeworm Echinococcus granulosus sensu lato (E. granulosus s.l.) caused a chronic infection, known as cystic echinococcosis (CE), which is a worldwide public health problem. The human secondary CE is caused by the dissemination of protoscoleces (PSCs) when fertile cysts are accidentally ruptured, followed by development of PSCs into new metacestodes. The local immune mechanisms responsible for the establishment and established phases after infection with E. granulosus s.l. are not clear. Here, we showed that T cells were involved in the formation of the immune environment in the liver in CE patients and Echinococcus granulosus sensu strict (E. granulosus s.s.)-infected mice, with CD4⁺ T cells being the dominant immune cells; this process was closely associated with cyst viability and establishment. Local T2-type responses in the liver were permissive for early infection establishment by E. granulosus s.s. between 4 and 6 weeks in the experimental model. CD4⁺ T-cell deficiency promoted PSC development into cysts in the liver in E. granulosus s.s.-infected mice. In addition, CD4⁺ T-cell-mediated cellular immune responses and IL-10-producing CD8⁺ T cells play a critical role in the establishment phase of secondary E. granulosus s.s. PSC infection. These data contribute to the understanding of local immune responses to CE and the design of new therapies by restoring effective immune responses and blocking evasion mechanisms during the establishment phase of infection.

Advances in the pharmacological treatment of hepatic alveolar echinococcosis: From laboratory to clinic

Hepatic alveolar echinococcosis (HAE) is a zoonotic parasitic disease caused by the larvae of Echinococcus multilocularis. Because of its characteristics of diffuse infiltration and growth similar to tumors, the disability rate and mortality rate are high among patients. Although surgery (including hepatectomy, liver transplantation, and autologous liver transplantation) is the first choice for the treatment of hepatic alveolar echinococcosis in clinic, drug treatment still plays an important and irreplaceable role in patients with end-stage echinococcosis, including patients with multiple organ metastasis, patients with inferior vena cava invasion, or patients with surgical contraindications, etc. However, Albendazole is the only recommended clinical drug which could exhibit a parasitostatic rather than a parasitocidal effect. Novel drugs are needed but few investment was made in the field because the rarity of the cases. Drug repurposing might be a solution. In this review, FDA-approved drugs that have a potential curative effect on hepatic alveolar echinococcosis in animal models are summarized. Further, nano drug delivery systems boosting the therapeutic effect on hepatic alveolar echinococcosis are also reviewed. Taken together, these might contribute to the development of novel strategy for advanced hepatic alveolar echinococcosis.

Serum platelet-derived growth factor-BB levels as a potential biomarker in assessing the metabolic activity of lesions in alveolar echinococcosis patients

BACKGROUND

Alveolar echinococcosis (AE) is a chronic disease caused by the larval stage of Echinococcus multilocularis. Assessing the metabolic activity of AE lesions is critical to evaluate disease progression and survey treatment options. There is an urgent need to identify more rapid, convenient, and non-invasive clinical detection methods to substitute the current techniques. Herein, we evaluated the viability of platelet-derived growth factor-BB (PDGF-BB) as a biomarker for detecting the metabolic activity of AE patients and their correlations with clinicopathological features of AE patients.

METHODS

Sera were collected from 28 AE patients and a homogenous cohort of 28 healthy individuals. The concentration of serum PDGF-BB homodimers (sPDGF-BB) was assessed via an enzyme-linked immunosorbent assay (ELISA). Liver tissue samples were obtained from a consecutive series of 28 AE patients who underwent surgical resection. Thereafter, we determined the expression levels of local PDGF-BB and platelet-derived growth factor receptor-β (PDGFR-β) through immunohistochemistry (IHC). Correlations of PDGF-BB expression levels with clinicopathological features of AE patients were analyzed using SPSS.

RESULTS

The concentrations of sPDGF-BB were significantly lower in AE patients (p < 0.0001), particularly in High Metabolically Active AE patients (HMAE) patients (p < 0.05). The expression levels of PDGF-BB and its receptor were both significantly higher in close liver tissue (CLT) in AE patients (p < 0.0001). We also found that metabolically active AE and sPDGF-BB are significantly negatively correlated (r = -0.624, p = 0.0004). Beside, the local expression levels of PDGF-BB was positively correlated with metabolic activity, PNM stage, and lesion size. Notably, the sPDGF-BB levels were proposed as a potential biomarker for assessing metabolic activity of AE, with 81.0% sensitivity and 85.7% specificity (95% confidence interval, p = 0.003).

CONCLUSIONS

Serum levels of PDGF-BB could be a simple, non-invasive, and quick biomarker for assessing the metabolic activity of lesions in AE patients.

Involvement of TIGIT in Natural Killer Cell Exhaustion and Immune Escape in Patients and Mouse Model With Liver Echinococcus multilocularis Infection

BACKGROUND AND AIMS

Alveolar echinococcosis (AE) is a lethal helminthic liver disease caused by persistent infection with Echinococcus multilocularis. Although more attention has been paid to the immunotolerance of T cells caused by E. multilocularis infection, the role of natural killer (NK) cell, a critical player in liver immunity, is seldom studied.

APPROACH AND RESULTS

Here, we observed that NK cells from the blood and closed liver tissue (CLT) of AE patients expressed a higher level of inhibitory receptor TIGIT and were functionally exhausted with a lower expression of granzyme B, perforin, interferon-gamma (IFN-γ), and TNF-α. Addition of anti-TIGIT (T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain) monoclonal antibody into AE patients' peripheral blood mononuclear cell culture significantly enhanced the synthesis of IFN-γ and TNF-α by NK cells, indicating the reversion of exhausted NK cells by TIGIT blockade. In the mouse model of E. multilocularis infection, liver and splenic TIGIT⁺ NK cells progressively increased dependent of infection dosage and timing and were less activated and less degranulated with lower cytokine secretion. Furthermore, TIGIT deficiency or blockade in vivo inhibited liver metacestode growth, reduced liver injury, and increased the level of IFN-γ produced by liver NK cells. Interestingly, NK cells from mice with persistent chronic infection expressed a higher level of TIGIT compared to self-healing mice. To look further into the mechanisms, more regulatory CD56^bright and murine CD49a⁺ NK cells with higher TIGIT expression existed in livers of AE patients and mice infected with E. multilocularis, respectively. They coexpressed higher surface programmed death ligand 1 and secreted more IL-10, two strong inducers to mediate the functional exhaustion of NK cells.

CONCLUSIONS

Our results indicate that inhibitory receptor TIGIT is involved in NK cell exhaustion and immune escape from E. multilocularis infection.

Immune checkpoint molecule TIGIT manipulates T cell dysfunction in septic patients

Sepsis is a dysregulated host response to infection. T cell dysfunction results in the failure to eradicate pathogens and the increased susceptibility to nosocomial infections and mortality during sepsis. Although PD-1 has shown to be a promising target to interfere with T cells dysfunction, the role of other coinhibitory receptors in sepsis remains largely elusive. Here we demonstrated that the immune checkpoint molecule TIGIT on lymphocytes and the critical role of TIGIT in regulating T cell responses in sepsis. Fifty septic patients and seventeen healthy donors were prospectively enrolled. The expression patterns of TIGIT and other molecules on lymphocytes were quantitated by flow cytometry. Ex vivo functional assays were also conducted. Results show that TIGIT expression on T cells was significantly upregulated in sepsis and septic shock patients relative to healthy donors. Elevated frequencies of TIGIT⁺ T cells correlated with aggravated inflammatory response and organ injuries. Of note, TIGIT expression on CD8⁺ T cells showed a competitive capability to predict ICU mortality in sepsis. TIGIT⁺ T cells expressed higher levels of PD-1, lower levels of CD226, and released fewer cytokines. Strikingly, ex vivo blockade of TIGIT using anti-TIGIT antibody restored the frequencies of cytokine-producing T cells from septic patients. These data illustrate that TIGIT on T cells is being used not only as a clinical predictor of poor prognosis but also as a potential target of novel immunotherapeutic intervention during sepsis.

Alveolar echinococcosis: what triggers emergence in North America, Central Europe and Asia?

PURPOSE OF REVIEW

Infection with the larval (metacestode) stage of Echinococcus multilocularis causes alveolar echinococcosis (AE), a serious hepatic disorder. The parasite has increased its infection extensity in wildlife and domestic dogs, mainly due to urbanization and spatial extension of wildlife hosts in Europe, Asia as well as North America, resulting in emerging infection risk for humans.

RECENT FINDINGS

In hyperendemic areas such as Kyrgyzstan and China, ecological and socioeconomic changes have been associated with the unpredictable increase of AE cases. In North America, the appearance of the European-like genotype is of concern. In Europe, the annual increase of human case numbers reached a plateau even in hyperendemic situations. Therefore, we conclude that most of the exposed individuals are resistant to parasite invasion and/or to disease development. Thus, AE develops in a few healthy individuals, but preferentially in immunosuppressed patients.

SUMMARY

In the future, improved diagnostic strategies will allow more precise estimations of transmission routes including the role of food, water and direct dog contact, which should yield improved public health recommendations. Finally, understanding protective innate and acquired immune mechanisms as well as parasite-driven immune-evasion processes will be essential to develop curative therapies in nonoperable patients and, futuristically, appropriate vaccines.

TIGIT Induces (CD3+) T Cell Dysfunction in Colorectal Cancer by Inhibiting Glucose Metabolism

T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) is an immunosuppressive receptor expressed on the surface of immune cells, suppressing immune responses by activating the intracellular negative regulatory signals. TIGIT plays an important role in the pathogenesis of various tumors, but its immune escape in colorectal cancer remains unclear. We found that the proportion of CD3+TIGIT+ T cells was increased in peripheral blood and cancer tissue in colorectal cancer patients when compared with the healthy donors. These cells exhibited functional defects, low proliferative activity, impaired cytokine production and reduced glucose metabolism. A strong association was also observed between the elevated TIGIT expression and poor prognosis in this cohort. In the in vitro co-culture assays of T cells and tumor cells, the suppressed glucose metabolic activity of T cells was reversed by TIGIT blockade. In addition, this blockade induced the apoptosis and reduced G2/M transit in tumor cells. The antitumor efficacy of TIGIT Ab therapy was further demonstrated in a human colorectal xenograft mice model while co-blockers of TIGIT and PD-1 exhibited synergistic suppressing effects on tumor growth. These results suggest that while TIGIT induces CD3+ T cell dysfunction in colorectal cancer, co-targeting TIGIT and PD-1 can lead to an effective antitumor response and may serve as a novel therapeutic strategy for colorectal patients.

Dynamic Expressions of TIGIT on Splenic T Cells and TIGIT-Mediated Splenic T Cell Dysfunction of Mice With Chronic Toxoplasma gondii Infection

As an immunosuppressive receptor, T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) play a critical part in cellular immune regulation mediated by pathogen infection. Whereas, TIGIT expression on splenic T cells in hosts infected with Toxoplasma gondii cysts has not been studied. In this study, we detected TIGIT expression and the changes of immune function in the spleen by flow cytometry and real-time PCR (RT-PCR). We found that TIGIT expression on splenic T cells increased significantly post infection. At the same time, splenic TIGIT⁺T_CM cells were activated and transformed into TIGIT⁺T_EM cells during the infection, and the cytotoxicity of TIGIT⁺ T cells was reduced in the later stage of infection. This study shows that chronic T. gondii infection can upregulate TIGIT expression on the surface of T cells and affect immune cell function.

Hepatic Alveolar Echinococcosis

Hepatic alveolar echinococcosis (HAE) is a rare but severe zoonosis caused by the pseudotumoral intrahepatic development of the larval stage of the tapeworm Echinococcus multilocularis. HAE is present only in the Northern Hemisphere, predominantly in China. Currently, there is a significant resurgence of cases in historically endemic areas associated with emergence of HAE in countries not previously concerned. Today, in European countries, HAE is often discovered by chance; however, clinicians should be made aware of opportunistic infections that progressively emerged recently as a result of therapeutic or pathological immunosuppression. Ultrasonography is the key first-line diagnostic procedure, with specific serology providing confirmation in 95% of the cases. Albendazole, only parasitostatic, is the mainstay for treatment. Surgical resection, if feasible, is the gold standard for treatment, and more patients are currently eligible for this option because of an earlier diagnosis. The prognosis has considerably improved but remains poor in countries where access to care is less favorable.

Quantitative evaluation of range and metabolic activity of hepatic alveolar echinococcosis lesion microenvironment using PET/CT and multi-site sampling method

Background

Alveolar echinococcosis (AE) lesion microenvironment (LME) is crucial site where parasite-host interactions happen and of great significance during surgery and obtaining liver samples for basic research. However, little is known about quantification of LME range and its’ metabolic activity regarding different lesion characteristics.

Methods

A prospective and retrospective analysis of LME from surgical AE patients was performed. Patients (n = 75) received abdominal computed tomography (CT) and position emission tomography/computed tomography using ¹⁸F-fluodeoxyglucose (¹⁸F-FDG-PET/CT) within 1 week prior to surgery. Semiquantitatively, calcification was clustered with 0%, < 50% and ≥ 50% degrees at lesion periphery; liquefaction was clustered with 0%, < 50%, 50 ~ 75%, ≥75% degrees at lesion center using volumetric ratio. Tumor to background ratio (TBR) of ¹⁸F-FDG standard uptake value (SUV, n = 75) was calculated, and range of ¹⁸F-FDG uptake area was measured; Multi-site sampling method (MSS, n = 35) was introduced to obtain histological slides to evaluate immune cell infiltrative ranges.

Results

Altogether six major lesion groups have been identified (A: 0% calcified, 0% liquefied; B: ≥50% calcified, 0% liquefied; C: < 50% calcified, < 50% liquefied; D: ≥50% calcified, < 50% liquefied; E: < 50% calcified, 50 ~ 75% liquefied; F: ≥50% calcified, ≥75% liquefied). Statistically, TBR values respectively were 5.1 ± 1.9, 2.7 ± 1.2, 4.2 ± 1.2, 2.7 ± 0.7, 4.6 ± 1.2, 2.9 ± 1.1 in groups A ~ F, and comparisons showed A > B, A > D, A > F, E > B, E > D, E > F, C > B, C > D, C > F (P < 0.05); LME ranges indicated by PET/CT respectively were 14.9 ± 3.9, 10.6 ± 1.5, 12.3 ± 1.1, 7.8 ± 1.6, 11.1 ± 2.3, 7.0 ± 0.4 mm in groups A ~ F, and comparisons showed A > B, A > D, A > F, A > E, C > B, C > D, C > F, E > D, E > F, B > D, B > F (P < 0.05); LME ranges indicated by MSS respectively were 17.9 ± 4.9, 13.0 ± 2.7, 11.9 ± 2.6, 6.0 ± 2.2, 11.0 ± 4.1, 6.0 ± 2.2 mm in groups A ~ F, and comparisons showed A > C, A > D, A > F, B > D, B > F, C > D, C > F (P < 0.05). Generally, less calcifications indicated higher TBR values and wider LME ranges; and, severer liquefactions indicated smaller LME ranges. Additionally, patients with previous medication history had lower TBR values.

Conclusions

PET/CT and MSS method showed distinct TBRs and LME ranges for different calcifications and liquefactions. This study would be able to provide references for both surgical resections of lesions and more accurate sample acquisitions for basic research targeted to immunology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06366-3.

Identification of candidate biomarkers of liver hydatid disease via microarray profiling, bioinformatics analysis, and machine learning

Objectives

Liver echinococcosis is a severe zoonotic disease caused by Echinococcus (tapeworm) infection, which is epidemic in the Qinghai region of China. Here, we aimed to explore biomarkers and establish a predictive model for the diagnosis of liver echinococcosis.

Methods

Microarray profiling followed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis was performed in liver tissue from patients with liver hydatid disease and from healthy controls from the Qinghai region of China. A protein–protein interaction (PPI) network and random forest model were established to identify potential biomarkers and predict the occurrence of liver echinococcosis, respectively.

Results

Microarray profiling identified 1152 differentially expressed genes (DEGs), including 936 upregulated genes and 216 downregulated genes. Several previously unreported biological processes and signaling pathways were identified. The FCGR2B and CTLA4 proteins were identified by the PPI networks and random forest model. The random forest model based on FCGR2B and CTLA4 reliably predicted the occurrence of liver hydatid disease, with an area under the receiver operator characteristic curve of 0.921.

Conclusion

Our findings give new insight into gene expression in patients with liver echinococcosis from the Qinghai region of China, improving our understanding of hepatic hydatid disease.

Impact of Albendazole on Cytokine and Chemokine Response Profiles in Echinococcus multilocularis-Inoculated Mice

Objective

Alveolar echinococcosis (AE) is a zoonosis caused by the larval stage of the metacestode Echinococcosis multilocularis with a tumor-like behavior in the targeted organ, especially in the liver. Surgery with albendazole is first-line modality for AE. Drug discontinuation is usually based upon the parasitic viability shown by the positron emission tomography (PET) scan. However, as a demanding and expensive method, it is not widely practiced in majority of the endemic regions. Further understanding on the cytokine and chemokine response profiles in AE patients may provide an interesting insight for potential markers in viability assessment.

Methods

Mice were inoculated with Echinococcus multilocularis intrahepatically to develop the hepatic AE murine model. Oral albendazole administration was then applied for three months after the first inoculation, and peripheral and regional immune cells including type 1 T helper cells (Th), Th2, Th17, regulatory T (Treg) cells, related cytokines, and chemokines were examined.

Results

The hepatic AE lesion was confirmed by ultrasound examination resulting in a successful rate of 70%. Among the 17 cytokines and chemokines detected, plasma levels of IL-23 were significantly higher in E. multilocularis-infected mice when compared to the control group; furthermore, more obvious increasing levels were found after albendazole treatment (p < 0.05). All chemokine levels other than eotaxin and MCP-3 were slightly higher in E. multilocularis-infected mice compared to the control group (p > 0.05). Eotaxin levels were significantly decreased in mice with E. multilocularis infection followed by albendazole treatment (p < 0.05). Both IL-17A and IL-23 expressions in hepatic AE lesions were significantly higher and related with disease activity.

Conclusion

Albendazole administration influenced the balance of immune response and promotes the secretion of proinflammatory factors which is beneficial to parasite clearance. IL-23 seems to be associated with the successful albendazole treatment in mice with E. multilocularis infection; such a change could be translated into clinical application in the near future.

Innate and adaptive immune responses following PD-L1 blockade in treating chronic murine alveolar echinococcosis

BACKGROUND

Programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) immune checkpoint blockade are efficacious in certain cancer therapies.

OBJECTIVES

The present study aimed to provide a picture about the development of innate and adaptive immune responses upon PD-L1 blockade in treating chronic murine AE.

METHODS

Immune treatment started at 6 weeks post-E. multilocularis infection, and was maintained for 8 weeks with twice per week anti-PD-L1 administration (intraperitoneal). The study included an outgroup-control with mice perorally medicated with albendazole 5 d/wk, and another one with both treatments combined. Assessment of treatment efficacy was based on determining parasite weight, innate and adaptive immune cell profiles, histopathology and liver tissue cytokine levels.

RESULTS/CONCLUSIONS

Findings showed that the parasite load was significantly reduced in response to PD-L1 blockade, and this blockade (a) contributed to T-cell activity by increasing CD4⁺ /CD8⁺ effector T cells, and decreasing Tregs; (b) had the capacity to restore DCs and Kupffer cells/Macrophages; (c) suppressed NKT and NK cells; and thus (d) lead to an improved control of E. multilocularis infection in mice. This study suggests that the PD-L1 pathway plays an important role by regulating adaptive and innate immune cells against E. multilocularis infection, with significant modulation of tissue inflammation.

Investigating new serological and tissue markers for the follow-up of patients operated for alveolar echinococcosis

AIMS

Alveolar echinococcosis (AE) is characterized by a chronically progressing hepatic injury caused by Echinococcus multilocularis. Surgery presently remains the best curative option. Currently, biological predictive features derived from the resected specimens are not suitable to assess surgery efficacy. The present study was designed to investigate whether a selection of markers measured on the resected specimens exhibits predictive features related to parasite viability, or to a total elimination of the parasite, in addition to serological markers.

METHODS AND RESULTS

In a collaboration between two centres, one in France (Besançon), and one in Switzerland (Bern), samples from 40 AE patients were analysed by microarray and serology techniques, individually. Paired serum samples before and after surgery were obtained for 26 patients. In the sera, a significant decrease in PD-L1 levels was observed after surgery, in addition to anti-Em18 levels. In the liver tissue, low levels of Cluster of Differentiation (CD)-3 were correlated with the absence of serum anti-Em18 after surgery.

CONCLUSION

This study showed PD-L1 is promising as a potential serological marker and further confirmed the performance of anti-Em18 serology. Further studies on a larger cohort are needed to confirm the utility of performing systematically microarray on resected liver tissue.

Expression of TIGIT in splenic and circulatory T cells from mice acutely infected with Toxoplasma gondii

The surface protein TIGIT (T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain) has been characterized as an important regulator of cell-mediated immune responses in various infections. However, TIGIT expression in immune cells of mice infected with Toxoplasma gondii has not been investigated. Here, we detected TIGIT expression and related phenotypes by flow cytometry and real-time PCR in splenic and circulatory T cells of mice infected with the T. gondii RH strain. We found that the expression of TIGIT on the surface of CD4⁺ T cells and CD8⁺ T cells from the spleen and peripheral blood mononuclear cells decreased in the early stage, but increased significantly in the late stage of acute T. gondii infection in mice. Importantly, TIGIT expression was positively correlated with lesions in the murine spleen. In addition, T. gondii-specific TIGIT⁺T_CM cells in the spleen were activated and transformed into TIGIT⁺ T_EM cells. Hematoxylin and eosin staining of spleen sections and real-time PCR showed that the severity of splenic lesions was positively correlated with the T. gondii load. This study demonstrates that acute T. gondii infection can regulate the expression of TIGIT in T cells and affect immune cell function.

Dual Role of Hepatic Macrophages in the Establishment of the Echinococcus multilocularis Metacestode in Mice

Echinococcus multilocularis larvae, predominantly located in the liver, cause a tumor-like parasitic disease, alveolar echinococcosis (AE), that is characterized by increased infiltration of various immune cells, including macrophages, around the lesion that produces an "immunosuppressive" microenvironment, favoring its persistent infection. However, the role of hepatic macrophages in the host defense against E. multilocularis infection remains poorly defined. Using human liver tissues from patients with AE and a hepatic experimental mouse model of E. multilocularis, we investigated the phenotype and function of hepatic macrophages during the parasite infection. In the present study, we found that a large number of CD68⁺ macrophages accumulated around the metacestode lesion in the liver of human AE samples and that both S100A9⁺ proinflammatory (M1 phenotype) and CD163⁺ anti-inflammatory (M2 phenotype) macrophages were significantly higher in close liver tissue (CLT) than in distant liver tissue (DLT), whereas M2 macrophages represent the dominant macrophage population. Furthermore, E. multilocularis-infected mice exhibited a massive increase in macrophage (F4/80⁺) infiltration in the liver as early as day 5, and the infiltrated macrophages were mainly monocyte-derived macrophages (CD11b^hi F4/80^int MoMFs) that preferentially differentiated into the M1 phenotype (iNOS⁺) at the early stage of E. multilocularis infection and then polarized to anti-inflammatory macrophages of the M2 phenotype (CD206⁺) at the chronic stage of infection. We further showed that elimination of macrophages by treatment of mice with clodronate-liposomes before E. multilocularis infection impaired worm expulsion and was accompanied by a reduction in liver fibrosis, yielding a high parasite burden. These results suggest that hepatic macrophages may play a dual role in the establishment and development of E. multilocularis metacestodes in which early larvae clearance is promoted by M1 macrophages while persistent metacestode infection is favored by M2 macrophages.

Immune profile of the tumor microenvironment and the identification of a four-gene signature for lung adenocarcinoma

The composition and relative abundances of immune cells in the tumor microenvironment are key factors affecting the progression of lung adenocarcinomas (LUADs) and the efficacy of immunotherapy. Using the cancer gene expression dataset from The Cancer Genome Atlas (TCGA) program, we scored stromal and immune cells for tumor purity prediction by CIBERSORT and ESTMATE. Differential expression analysis was employed to identify 374 genes between the high-score group and the low-score group, which were utilized to conduct Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Protein-protein interaction (PPI) and Cox regression analysis were performed on the differentially expressed genes (DEGs) to identify four key tumor microenvironment (TME) -related genes (CCR2, CCR4, P2RY12, and P2RY13). The expression levels of the four DEGs differed significantly among LUAD patients of different ages, genders, and TNM stages. We found that the infiltration of resting memory CD4+ T cells, memory B cells, and M0 macrophages into the TME was co-regulated by these four DEGs. These four genes were closely related to the prognosis of LUAD and affected the infiltration of immune cells into the TME, which had predictive prognostic value in LUAD.

Immunosuppressive Property of MSCs Mediated by Cell Surface Receptors

In the past decade, mesenchymal stem cells (MSCs) tend to exhibit inherent tropism for refractory inflammatory diseases and engineered MSCs have appeared on the market as therapeutic agents. Recently, engineered MSCs target to cell surface molecules on immune cells has been a new strategy to improve MSC applications. In this review, we discuss the roles of multiple receptors (ICAM-1, Gal-9, PD-L1, TIGIT, CD200, and CXCR4) in the process of MSCs' immunosuppressive properties. Furthermore, we discuss the principles and strategies for developing receptor-regulated MSCs and their mechanisms of action and the challenges of using MSCs as immunosuppressive therapies.