Kupffer cells promote T-cell hepatitis by producing CXCL10 and limiting liver sinusoidal endothelial cell permeability

Dissection of molecular mechanisms of liver injury induced by microcystin-leucine arginine via single-cell RNA-sequencing

The occurrence of poisoning incidents caused by cyanobacterial blooms has aroused wide public concern. Microcystin-leucine arginine (MC-LR) is a well-established toxin produced by cyanobacterial blooms, which is widely distributed in eutrophic waters. MC-LR is not only hazardous to the water environment but also exerts multiple toxic effects including liver toxicity in both humans and animals. However, the underlying mechanisms of MC-LR-induced liver toxicity are unclear. Herein, we used advanced single-cell RNA sequencing technology to characterize MC-LR-induced liver injury in mice. We established the first single-cell atlas of mouse livers in response to MC-LR. Our results showed that the differentially expressed genes and pathways in diverse cell types of liver tissues of mice treated with MC-LR are highly heterogeneous. Deep analysis showed that MC-LR induced an increase in a subpopulation of hepatocytes that highly express Gstm3, which potentially contributed to hepatocyte apoptosis in response to MC-LR. Moreover, MC-LR increased the proportion and multiple subtypes of Kupffer cells with M1 phenotypes and highly expressed proinflammatory genes. Furthermore, the MC-LR increased several subtypes of CD8+ T cells with highly expressed multiple cytokines and chemokines. Overall, apart from directly inducing hepatocytes apoptosis, MC-LR activated proinflammatory Kupffer cell and CD8+ T cells, and their interaction may constitute a hostile microenvironment that contributes to liver injury. Our findings not only present novel insight into underlying molecular mechanisms but also provide a valuable resource and foundation for additional discovery of MC-LR-induced liver toxicity.

Pathoimmunological analyses of fatal E11 infection in premature infants

E11 causes acute fulminant hepatitis in newborns. We investigated the pathological changes of different tissues from premature male twins who died due to E11 infection. The E11 expression level was higher in the liver than in other tissues. IP10 was upregulated in liver tissue in the patient group, and might be regulated by IFNAR and IRF7, whereas IFNα was regulated by IFNAR or IRF5.

mmu-miR-374b-5p modulated inflammatory factors via downregulation of C/EBP β/NF-κB signaling in Kupffer cells during Echinococcus multilocularis infection

BACKGROUND

Alveolar echinococcosis (AE) is an important infectious disease caused by the metacestode larvae of Echinococcus multilocularis, seriously threatening global public health security. Kupffer cells (KCs) play important roles in liver inflammatory response. However, their role in hepatic alveolar echinococcosis has not yet been fully elucidated.

METHODS

In this study, qRT-PCR was used to detect the expression level of miR-374b-5p in KCs. The target gene of miR-374b-5p was identified through luciferase reporter assays and loss of function and gains. Critical genes involved in NFκB signaling pathway were analyzed by qRT-PCR and western blot.

RESULTS

This study reported that miR-374b-5p was significantly upregulated in KCs during E. multilocularis infection and further showed that miR-374b-5p was able to bind to the 3'-UTR of the C/EBP β gene and suppressed its expression. The expression levels of NF-κBp65, p-NF-κBp65 and pro-inflammatory factors including iNOS, TNFα and IL6 were attenuated after overexpression of miR-374b-5p while enhanced after suppression of miR-374b-5p. However, the Arg1 expression level was promoted after overexpression of miR-374b-5p while suppressed after downregulation of miR-374b-5p. Additionally, increased protein levels of NF-κBp65 and p-NF-κBp65 were found in the C/EBP β-overexpressed KCs.

CONCLUSIONS

These results demonstrated that miR-374b-5p probably regulated the expression of inflammatory factors via C/EBP β/NF-κB signaling. This finding is helpful to explore the mechanism of inflammation regulation during E. multilocularis infection.

Endothelium-targeted Ddx24 conditional knockout exacerbates ConA-induced hepatitis in mice due to vascular hyper-permeability

BACKGROUND

Acute hepatitis is a progressive inflammatory disorder that can lead to liver failure. Endothelial permeability is the vital pathophysiological change involved in infiltrating inflammatory factors. DDX24 has been implicated in immune signaling. However, the precise role of DDX24 in immune-mediated hepatitis remains unclear. Here, we investigate the phenotype of endothelium-targeted Ddx24 conditional knockout mice with Concanavalin A (ConA)-induced hepatitis.

METHODS

Mice with homozygous endothelium-targeted Ddx24 conditional knockout (Ddx24flox/flox; Cdh5-Cre+) were established using the CRISPR/Cas9 mediated Cre-loxP system. We investigated the biological functions of endothelial cells derived from transgenic mice and explored the effects of Ddx24 in mice with ConA-induced hepatitis in vivo. The mass spectrometry was performed to identify the differentially expressed proteins in liver tissues of transgenic mice.

RESULT

We successfully established mice with endothelium-targeted Ddx24 conditional knockout. The results showed migration and tube formation potentials of murine aortic endothelial cells with DDX24 silencing were significantly promoted. No differences were observed between Ddx24flox/flox; Cdh5-Cre+ and control regarding body weight and length, pathological tissue change and embryogenesis. We demonstrated Ddx24flox/flox; Cdh5-Cre+ exhibited exacerbation of ConA-induced hepatitis by up-regulating TNF-α and IFN-γ. Furthermore, endothelium-targeted Ddx24 conditional knockout caused vascular hyper-permeability in ConA-injected mice by down-regulating vascular integrity-associated proteins. Mechanistically, we identified Ddx24 might regulate immune-mediated hepatitis by inflammation-related permeable barrier pathways.

CONCLUSION

These findings prove that endothelium-targeted Ddx24 conditional knockout exacerbates ConA-induced hepatitis in mice because of vascular hyper-permeability. The findings indicate a crucial role of DDX24 in regulating immune-mediated hepatitis, suggesting DDX24 as a potential therapeutic target in the disorder.

AIM2 regulates autophagy to mitigate oxidative stress in aged mice with acute liver injury

The cytoplasmic pattern recognition receptor, absent in melanoma 2 (AIM2), detects cytosolic DNA, activating the inflammasome and resulting in pro-inflammatory cytokine production and pyroptotic cell death. Recent research has illuminated AIM2's contributions to PANoptosis and host defense. However, the role of AIM2 in acetaminophen (APAP)-induced hepatoxicity remains enigmatic. In this study, we unveil AIM2's novel function as a negative regulator in the pathogenesis of APAP-induced liver damage in aged mice, independently of inflammasome activation. AIM2-deficient aged mice exhibited heightened lipid accumulation and hepatic triglycerides in comparison to their wild-type counterparts. Strikingly, AIM2 knockout mice subjected to APAP overdose demonstrated intensified liver injury, compromised mitochondrial stability, exacerbated glutathione depletion, diminished autophagy, and elevated levels of phosphorylated c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK). Furthermore, our investigation revealed AIM2's mitochondrial localization; its overexpression in mouse hepatocytes amplified autophagy while dampening JNK phosphorylation. Notably, induction of autophagy through rapamycin administration mitigated serum alanine aminotransferase levels and reduced the necrotic liver area in AIM2-deficient aged mice following APAP overdose. Mechanistically, AIM2 deficiency exacerbated APAP-induced acute liver damage and inflammation in aged mice by intensifying oxidative stress and augmenting the phosphorylation of JNK and ERK. Given its regulatory role in autophagy and lipid peroxidation, AIM2 emerges as a promising therapeutic target for age-related acute liver damage treatment.

Interorgan communication with the liver: novel mechanisms and therapeutic targets

The liver is a multifunctional organ that plays crucial roles in numerous physiological processes, such as production of bile and proteins for blood plasma, regulation of blood levels of amino acids, processing of hemoglobin, clearance of metabolic waste, maintenance of glucose, etc. Therefore, the liver is essential for the homeostasis of organisms. With the development of research on the liver, there is growing concern about its effect on immune cells of innate and adaptive immunity. For example, the liver regulates the proliferation, differentiation, and effector functions of immune cells through various secreted proteins (also known as "hepatokines"). As a result, the liver is identified as an important regulator of the immune system. Furthermore, many diseases resulting from immune disorders are thought to be related to the dysfunction of the liver, including systemic lupus erythematosus, multiple sclerosis, and heart failure. Thus, the liver plays a role in remote immune regulation and is intricately linked with systemic immunity. This review provides a comprehensive overview of the liver remote regulation of the body's innate and adaptive immunity regarding to main areas: immune-related molecules secreted by the liver and the liver-resident cells. Additionally, we assessed the influence of the liver on various facets of systemic immune-related diseases, offering insights into the clinical application of target therapies for liver immune regulation, as well as future developmental trends.

Effects of Calorie Restriction and Fasting on Macrophage: Potential Impact on Disease Outcomes?

Energy restriction, including calorie restriction and fasting, has garnered significant attention for its potential therapeutic effects on a range of chronic diseases (such as diabetes, obesity, and cancer) and aging. Since macrophages are critical players in many diseases, their response to energy restriction may impact disease outcomes. However, the diverse metabolic patterns and functions of macrophages can lead to variability in the effects of energy restriction on macrophages across different tissues and disease states. This review outlines the effects of energy restriction on macrophages in several diseases, offering valuable guidance for future studies and insights into the clinical applications of calorie restriction and fasting.

Single-cell RNA sequencing reveals the effects of capsaicin in the treatment of sepsis-induced liver injury

Sepsis is a difficult-to-treat systemic condition in which liver dysfunction acts as both regulator and target. However, the dynamic response of diverse intrahepatic cells to sepsis remains poorly characterized. Capsaicin (CAP), a multifunctional chemical derived from chilli peppers, has recently been shown to potentially possess anti-inflammatory effects, which is also one of the main approaches for drug discovery against sepsis. We performed single-cell RNA transcriptome sequencing on 86,830 intrahepatic cells isolated from normal mice, cecal ligation and puncture-induced sepsis model mice and CAP-treated mice. The transcriptional atlas of these cells revealed dynamic changes in hepatocytes, macrophages, neutrophils, and endothelial cells in response to sepsis. Among the extensive crosstalk across these major subtypes, KC_Cxcl10 shared strong potential interaction with other cells when responding to sepsis. CAP mitigated the severity of inflammation by partly reversing these pathophysiologic processes. Specific cell subpopulations in the liver act collectively to escalate inflammation, ultimately causing liver dysfunction. CAP displays its health-promoting function by ameliorating liver dysfunction induced by sepsis. Our study provides valuable insights into the pathophysiology of sepsis and suggestions for future therapeutic gain.

Liver metastasis from colorectal cancer: pathogenetic development, immune landscape of the tumour microenvironment and therapeutic approaches

Colorectal cancer liver metastasis (CRLM) is one of the leading causes of death among patients with colorectal cancer (CRC). Although immunotherapy has demonstrated encouraging outcomes in CRC, its benefits are minimal in CRLM. The complex immune landscape of the hepatic tumour microenvironment is essential for the development of a premetastatic niche and for the colonisation and metastasis of CRC cells; thus, an in-depth understanding of these mechanisms can provide effective immunotherapeutic targets for CRLM. This review summarises recent studies on the immune landscape of the tumour microenvironment of CRLM and highlights therapeutic prospects for targeting the suppressive immune microenvironment of CRLM.

The role of CXCL family members in different diseases

Chemokines are a large family mediating a lot of biological behaviors including chemotaxis, tumor growth, angiogenesis and so on. As one member of this family, CXC subfamily possesses the same ability. CXC chemokines can recruit and migrate different categories of immune cells, regulate tumor's pathological behaviors like proliferation, invasion and metastasis, activate angiogenesis, etc. Due to these characteristics, CXCL subfamily is extensively and closely associated with tumors and inflammatory diseases. As studies are becoming more and more intensive, CXCLs' concrete roles are better described, and CXCLs' therapeutic applications including biomarkers and targets are also deeply explained. In this review, the role of CXCL family members in various diseases is summarized.

Remodeling the hepatic fibrotic microenvironment with emerging nanotherapeutics: a comprehensive review

Liver fibrosis could be the last hope for treating liver cancer and remodeling of the hepatic microenvironment has emerged as a strategy to promote the ablation of liver fibrosis. In recent years, especially with the rapid development of nanomedicine, hepatic microenvironment therapy has been widely researched in studies concerning liver cancer and fibrosis. In this comprehensive review, we summarized recent advances in nano therapy-based remodeling of the hepatic microenvironment. Firstly, we discussed novel strategies for regulatory immune suppression caused by capillarization of liver sinusoidal endothelial cells (LSECs) and macrophage polarization. Furthermore, metabolic reprogramming and extracellular matrix (ECM) deposition are caused by the activation of hepatic stellate cells (HSCs). In addition, recent advances in ROS, hypoxia, and impaired vascular remodeling in the hepatic fibrotic microenvironment due to ECM deposition have also been summarized. Finally, emerging nanotherapeutic approaches based on correlated signals were discussed in this review. We have proposed novel strategies such as engineered nanotherapeutics targeting antigen-presenting cells (APCs) or direct targeting T cells in liver fibrotic immunotherapy to be used in preventing liver fibrosis. In summary, this comprehensive review illustrated the opportunities in drug targeting and nanomedicine, and the current challenges to be addressed.

[Recent research on cytokines associated with anti-N-methyl-D-aspartate receptor encephalitis]

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune inflammatory disease of the central nervous system, and little is known about its immune mechanism at present. There is a lack of disease-related biomarkers in cerebrospinal fluid except anti-NMDAR antibody, which leads to delayed diagnosis and treatment in some patients. Therefore, there has been an increasing number of studies on related cytokines in recent years to assess whether they can be used as new biomarkers for evaluating disease conditions and assisting diagnosis and treatment. Current studies have shown that some cytokines may be associated with the progression of anti-NMDAR encephalitis, and this article reviews the research advances in such cytokines associated with anti-NMDAR encephalitis.

microRNAs-based diagnostic and therapeutic applications in liver fibrosis

Liver fibrosis is a process of over-extracellular matrix (ECM) aggregation and angiogenesis, which develops into cirrhosis and hepatocellular carcinoma (HCC). With the increasing pressure of liver fibrosis, new therapeutics to cure this disease requires much attention. Exosome-cargoed microRNAs (miRNAs) are emerging approaches in the precision of the liver fibrotic paradigm. In this review, we outlined the different types of hepatic cells derived miRNAs that drive intra-/extra-cellular interactive communication in liver fibrosis with different physiological and pathological processes. Specifically, we highlighted the possible mechanism of liver fibrosis pathogenesis associated with immune response and angiogenesis. In addition, potential clinical biomarkers and different stem cell transplant-derived miRNAs-based therapeutic strategies in liver fibrosis were summarized in this review. miRNAs-based approaches might help researchers devise new candidates for the cell-free treatment of liver fibrosis. This article is categorized under: RNA in Disease and Development > RNA in Disease.

Crosstalk between liver macrophages and gut microbiota: An important component of inflammation-associated liver diseases

Hepatic macrophages have been recognized as primary sensors and responders in liver inflammation. By processing host or exogenous biochemical signals, including microbial components and metabolites, through the gut-liver axis, hepatic macrophages can both trigger or regulate inflammatory responses. Crosstalk between hepatic macrophages and gut microbiota is an important component of liver inflammation and related liver diseases, such as acute liver injury (ALI), alcoholic liver disease (ALD), and nonalcoholic fatty liver disease (NAFLD). This review summarizes recent advances in knowledge related to the crosstalk between hepatic macrophages and gut microbiota, including the therapeutic potential of targeting hepatic macrophages as a component of gut microecology in inflammation-associated liver diseases.

Chemotactic cytokines secreted from Kupffer cells contribute to the sex-dependent susceptibility to non-alcoholic fatty liver diseases in mice

AIMS

The global prevalence of non-alcoholic fatty liver disease (NAFLD) has rapidly increased over the last decade due to an elevated occurrence of metabolic syndromes. Importantly, the prevalence and severity of NAFLD is higher in men than in women. Therefore, in the present study we endeavored to identify the mechanistic disparity between male and female mice.

MAIN METHODS

Global gene transcriptomics analysis was done with the high-fat diet (HFD)-induced NAFLD model of male, female, and ovariectomized (OVX) female mice. The expression of CCL2, CXCL2, and CXCL10 in mRNA level and serum protein level was done by qPCR and ELISA each. Immunohistochemistry staining was used to observe hepatic immune cell infiltration. To analyzing portion of immune cells, flow cytometry was done with isolated liver cells from HFD-fed male and female mice. Primary mouse liver cells were isolated from male and female mice for in vitro studies.

KEY FINDINGS

We identified sex differences in inflammatory chemokines, CCL2, CXCL2, and CXCL10, with the expression of these chemokines enhanced in male and OVX, but not in female, mice after HFD feeding. Resident Kupffer cells (KCs) were identified as the major source of production of CCL2, CXCL2, and CXCL10 in the mouse NAFLD model. Notably, KCs obtained from male mice expressed higher levels of chemokines than those from female mice, indicating that KCs may mediate the sex discrepancy in NAFLD progression.

SIGNIFICANCE

Our findings offer new insights into the pathology of sex-specific differences in NAFLD, involving chemokines and KCs.

AhR Activation Leads to Attenuation of Murine Autoimmune Hepatitis: Single-Cell RNA-Seq Analysis Reveals Unique Immune Cell Phenotypes and Gene Expression Changes in the Liver

The aryl hydrocarbon receptor (AhR) is a ubiquitously expressed ligand-activated transcription factor. While initially identified as an environmental sensor, this receptor has been shown more recently to regulate a variety of immune functions. AhR ligands vary in structure and source from environmental chemicals such as 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and indoles found in cruciferous vegetables to endogenous ligands derived from tryptophan metabolism. In the current study, we used TCDD, a high affinity AhR ligand to study the impact of AhR activation in the murine model of autoimmune hepatitis (AIH). Primarily, we used single-cell RNA-sequencing (scRNA-seq) technology to study the nature of changes occurring in the immune cells in the liver at the cellular and molecular level. We found that AhR activation attenuated concanavalin A (ConA)-induced AIH by limiting chemotaxis of pro-inflammatory immune cell subsets, promoting anti-inflammatory cytokine production, and suppressing pro-inflammatory cytokine production. scRNA-seq analysis showed some unusual events upon ConA injection such as increased presence of mature B cells, natural killer (NK) T cells, CD4+ or CD8+ T cells, Kupffer cells, memory CD8+ T cells, and activated T cells while TCDD treatment led to the reversal of most of these events. Additionally, the immune cells showed significant alterations in the gene expression profiles. Specifically, we observed downregulation of inflammation-associated genes including Ptma, Hspe1, and CD52 in TCDD-treated AIH mice as well as alterations in the expression of migratory markers such as CXCR2. Together, the current study characterizes the nature of inflammatory changes occurring in the liver during AIH, and sheds light on how AhR activation during AIH attenuates liver inflammation by inducing phenotypic and genotypic changes in immune cells found in the liver.

Intercellular crosstalk of liver sinusoidal endothelial cells in liver fibrosis, cirrhosis and hepatocellular carcinoma

Intercellular crosstalk among various liver cells plays an important role in liver fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Capillarization of liver sinusoidal endothelial cells (LSECs) precedes fibrosis and accumulating evidence suggests that the crosstalk between LSECs and other liver cells is critical in the development and progression of liver fibrosis. LSECs dysfunction, a key event in the progression from fibrosis to cirrhosis, and subsequently obstruction of hepatic sinuses and increased intrahepatic vascular resistance (IHVR) contribute to development of portal hypertension (PHT) and cirrhosis. More importantly, immunosuppressive tumor microenvironment (TME), which is closely related to the crosstalk between LSECs and immune liver cells like CD8+ T cells, promotes advances tumorigenesis, especially HCC. However, the connections within the crosstalk between LSECs and other liver cells during the progression from liver fibrosis to cirrhosis to HCC have yet to be discussed. In this review, we first summarize the current knowledge of how different crosstalk between LSECs and other liver cells, including hepatocytes, hepatic stellate cells (HSCs), macrophoges, immune cells in liver and extra cellular matrix (ECM) contribute to the physiological function and the progrssion from liver fibrosis to cirrhosis, or even to HCC. Then we examine current treatment strategies for LSECs crosstalk in liver fibrosis, cirrhosis and HCC.

Identification of Gene-Set Signature in Early-Stage Hepatocellular Carcinoma and Relevant Immune Characteristics

Background

The incidence of hepatocellular carcinoma (HCC) is rising worldwide, and there is limited therapeutic efficacy due to tumor microenvironment heterogeneity and difficulty in early-stage screening. This study aimed to develop and validate a gene set-based signature for early-stage HCC (eHCC) patients and further explored specific marker dysregulation mechanisms as well as immune characteristics.

Methods

We performed an integrated bioinformatics analysis of genomic, transcriptomic, and clinical data with three independent cohorts. We systematically reviewed the crosstalk between specific genes, tumor prognosis, immune characteristics, and biological function in the different pathological stage samples. Univariate and multivariate survival analyses were performed in The Cancer Genome Atlas (TCGA) patients with survival data. Diethylnitrosamine (DEN)-induced HCC in Wistar rats was employed to verify the reliability of the predictions.

Results

We identified a Cluster gene that potentially segregates patients with eHCC from non-tumor, through integrated analysis of expression, overall survival, immune cell characteristics, and biology function landscapes. Immune infiltration analysis showed that lower infiltration of specific immune cells may be responsible for significantly worse prognosis in HCC (hazard ratio, 1.691; 95% CI: 1.171–2.441; p = 0.012), such as CD8 Tem and cytotoxic T cells (CTLs) in eHCC. Our results identified that Cluster C1 signature presented a high accuracy in predicting CD8 Tem and CTL immune cells (receiver operating characteristic (ROC) = 0.647) and cancerization (ROC = 0.946) in liver. As a central member of Cluster C1, overexpressed PRKDC was associated with the higher genetic alteration in eHCC than advanced-stage HCC (aHCC), which was also connected to immune cell-related poor prognosis. Finally, the predictive outcome of Cluster C1 and PRKDC alteration in DEN-induced eHCC rats was also confirmed.

Conclusions

As a tumor prognosis-relevant gene set-based signature, Cluster C1 showed an effective approach to predict cancerization of eHCC and its related immune characteristics with considerable clinical value.

TA allele of rs2070673 in the CYP2E1 gene is associated with lobular inflammation and nonalcoholic steatohepatitis in patients with biopsy-proven nonalcoholic fatty liver disease

BACKGROUND AND AIM

Cytochrome P450 2E1 (CYP2E1) plays a role in lipid metabolism, and by increasing hepatic oxidative stress and inflammation, the upregulation of CYP2E1 is involved in development of nonalcoholic steatohepatitis (NASH). We aimed to explore the relationship between CYP2E1-333A>T (rs2070673) and the histological severity of nonalcoholic fatty liver disease (NAFLD).

METHODS

We studied 438 patients with biopsy-proven NAFLD. NASH was defined as NAFLD Activity Score ≥ 5 with existence of steatosis, ballooning, and lobular inflammation. CYP2E1-333A>T (rs2070673) was genotyped by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Serum cytokines related to inflammation were measured by the Bio-plex 200 system to investigate possible mediating factors involved in the process.

RESULTS

The TA genotype of rs2070673 had a higher prevalence of moderate/severe lobular inflammation (27.6% vs 20.3% vs 13.3%, P < 0.01) and NASH (55.7% vs 42.4% vs 40.5%, P < 0.01) compared with the AA and TT genotypes, respectively. In multivariable regression modeling, the heterozygote state TA was associated with moderate/severe lobular inflammation (adjusted odds ratio: 2.31, 95% confidence interval 1.41-3.78, P < 0.01) or NASH (adjusted odds ratio: 1.82, 95% confidence interval 1.22-2.69, P < 0.01), independently of age, sex, common metabolic risk factors, and presence of liver fibrosis. Compared with no-NASH, NASH patients had significantly higher levels of serum interleukin-1 receptor antagonist, interleukin-18, and interferon-inducible protein-10 (IP-10), whereas only IP-10 was increased with the rs2070673 TA variant (P = 0.01). Mediation analysis showed that IP-10 was responsible for ~60% of the association between the rs2070672 and NASH.

CONCLUSIONS

The TA allele of rs2070673 is strongly associated with lobular inflammation and NASH, and this effect appears to be largely mediated by serum IP-10 levels.

Exosomes as mediators of intercellular crosstalk in metabolism

Exosomes are nanoparticles secreted by all cell types and are a large component of the broader class of nanoparticles termed extracellular vesicles (EVs). Once secreted, exosomes gain access to the interstitial space and ultimately the circulation, where they exert local paracrine or distal systemic effects. Because of this, exosomes are important components of an intercellular and intraorgan communication system capable of carrying biologic signals from one cell type or tissue to another. The exosomal cargo consists of proteins, lipids, miRNAs, and other RNA species, and many of the biologic effects of exosomes have been attributed to miRNAs. Exosomal miRNAs have also been used as disease biomarkers. The field of exosome biology and metabolism is rapidly expanding, with new discoveries and reports appearing on a regular basis, and it is possible that potential therapeutic approaches for the use of exosomes or miRNAs in metabolic diseases will be initiated in the near future.

Circulatory Inflammatory Mediators in the Prediction of Anti-Tuberculous Drug-Induced Liver Injury Using RUCAM for Causality Assessment

BACKGROUND

Anti-tuberculous (TB) medications are common causes of drug-induced liver injury (DILI). Limited data are available on systemic inflammatory mediators as biomarkers for predicting DILI before treatment. We aimed to select predictive markers among potential candidates and to formulate a predictive model of DILI for TB patients.

METHODS

Adult active TB patients from a prospective cohort were enrolled, and all participants received standard anti-tuberculous treatment. Development of DILI, defined as ≥5× ULN for alanine transaminase or ≥2.6× ULN of total bilirubin with causality assessment (RUCAM, Roussel Uclaf causality assessment method), was regularly monitored. Pre-treatment plasma was assayed for 15 candidates, and a set of risk prediction scores was established using Cox regression and receiver-operating characteristic analyses.

RESULTS

A total of 19 (7.9%) in 240 patients developed DILI (including six carriers of hepatitis B virus) following anti-TB treatment. Interleukin (IL)-22 binding protein (BP), interferon gamma-induced protein 1 (IP-10), soluble CD163 (sCD163), IL-6, and CD206 were significant univariable factors associated with DILI development, and the former three were backward selected as multivariable factors, with adjusted hazards of 0.20 (0.07-0.58), 3.71 (1.35-10.21), and 3.28 (1.07-10.06), respectively. A score set composed of IL-22BP, IP-10, and sCD163 had an improved area under the curve of 0.744 (p < 0.001).

CONCLUSIONS

Pre-treatment IL-22BP was a protective biomarker against DILI development under anti-TB treatment, and a score set by additional risk factors of IP-10 and sCD163 employed an adequate DILI prediction.

Endothelial cell infection and dysfunction, immune activation in severe COVID-19

Rationale: Pulmonary vascular endotheliitis, perivascular inflammation, and immune activation are observed in COVID-19 patients. While the initial SARS-CoV-2 infection mainly infects lung epithelial cells, whether it also infects endothelial cells (ECs) and to what extent SARS-CoV-2-mediated pulmonary vascular endotheliitis is associated with immune activation remain to be determined. Methods: To address these questions, we studied SARS-CoV-2-infected K18-hACE2 (K18) mice, a severe COVID-19 mouse model, as well as lung samples from SARS-CoV-2-infected nonhuman primates (NHP) and patient deceased from COVID-19. We used immunostaining, RNAscope, and electron microscopy to analyze the organs collected from animals and patient. We conducted bulk and single cell (sc) RNA-seq analyses, and cytokine profiling of lungs or serum of the severe COVID-19 mice. Results: We show that SARS-CoV-2-infected K18 mice develop severe COVID-19, including progressive body weight loss and fatality at 7 days, severe lung interstitial inflammation, edema, hemorrhage, perivascular inflammation, systemic lymphocytopenia, and eosinopenia. Body weight loss in K18 mice correlated with the severity of pneumonia, but not with brain infection. We also observed endothelial activation and dysfunction in pulmonary vessels evidenced by the up-regulation of VCAM1 and ICAM1 and the downregulation of VE-cadherin. We detected SARS-CoV-2 in capillary ECs, activation and adhesion of platelets and immune cells to the vascular wall of the alveolar septa, and increased complement deposition in the lungs, in both COVID-19-murine and NHP models. We also revealed that pathways of coagulation, complement, K-ras signaling, and genes of ICAM1 and VCAM1 related to EC dysfunction and injury were upregulated, and were associated with massive immune activation in the lung and circulation. Conclusion: Together, our results indicate that SARS-CoV-2 causes endotheliitis via both infection and infection-mediated immune activation, which may contribute to the pathogenesis of severe COVID-19 disease.

Tumor-Associated Macrophages-Implications for Molecular Oncology and Imaging

Tumor-associated macrophages (TAMs) represent the largest group of leukocytes within the tumor microenvironment (TME) of solid tumors and orchestrate the composition of anti- as well as pro-tumorigenic factors. This makes TAMs an excellent target for novel cancer therapies. The plasticity of TAMs resulting in varying membrane receptors and expression of intracellular proteins allow the specific characterization of different subsets of TAMs. Those markers similarly allow tracking of TAMs by different means of molecular imaging. This review aims to provides an overview of the origin of tumor-associated macrophages, their polarization in different subtypes, and how characteristic markers of the subtypes can be used as targets for molecular imaging and theranostic approaches.

CXCL10 is a Tumor Microenvironment and Immune Infiltration Related Prognostic Biomarker in Pancreatic Adenocarcinoma

Pancreatic adenocarcinoma (PAAD) is the 10th most common cancer worldwide and the outcomes for patients with the disease remain extremely poor. Precision biomarkers are urgently needed to increase the efficiency of early diagnosis and to improve the prognosis of patients. The tumor microenvironment (TME) and tumor immune infiltration are thought to impact the occurrence, progression, and prognosis of PAAD. Novel biomarkers excavated originating from the TME and immune infiltration may be effective in predicting the prognosis of PAAD patients. In the current study, the ESTIMATE and CIBERSORT algorithms were applied to estimate the division of immune and stromal components and the proportion of tumor-infiltrating immune cells in 182 PAAD cases downloaded from The Cancer Genome Atlas database. Intersection analyses of the Protein-Protein Interaction networks and Cox regression analysis identified the chemokine (CXC-motif) ligand 10 (CXCL10) as a predictive biomarker. We verified that CXCL10 in the TME negatively correlates with prognosis in PAAD and positively correlates with tumor cell differentiation. GSE62452 from the GEO database and cumulative survival analysis were performed to validate CXCL10 expression as an independent prognostic indicator. We also found that memory B cells, regulatory T cells, and macrophages M0 and M1 were correlated with the expression of CXCL10 indicating that expression of CXCL10 influenced the immune activity of the TME. Our data suggest that CXCL10 is beneficial as a prognostic indicator in PAAD patients and highlights the potential for immune targeted therapy in the treatment of PAAD.

Lung Expression of Human Angiotensin-Converting Enzyme 2 Sensitizes the Mouse to SARS-CoV-2 Infection

Preclinical mouse models that recapitulate some characteristics of coronavirus disease (COVID-19) will facilitate focused study of pathogenesis and virus-host responses. Human agniotensin-converting enzyme 2 (hACE2) serves as an entry receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to infect people via binding to envelope spike proteins. Herein we report development and characterization of a rapidly deployable COVID-19 mouse model. C57BL/6J (B6) mice expressing hACE2 in the lung were transduced by oropharyngeal delivery of the recombinant human adenovirus type 5 that expresses hACE2 (Ad5-hACE2). Mice were infected with SARS-CoV-2 at Day 4 after transduction and developed interstitial pneumonia associated with perivascular inflammation, accompanied by significantly higher viral load in lungs at Days 3, 6, and 12 after infection compared with Ad5-empty control group. SARS-CoV-2 was detected in pneumocytes in alveolar septa. Transcriptomic analysis of lungs demonstrated that the infected Ad5-hACE mice had a significant increase in IFN-dependent chemokines Cxcl9 and Cxcl10, and genes associated with effector T-cell populations including Cd3 g, Cd8a, and Gzmb. Pathway analysis showed that several Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were enriched in the data set, including cytokine-cytokine receptor interaction, the chemokine signaling pathway, the NOD-like receptor signaling pathway, the measles pathway, and the IL-17 signaling pathway. This response is correlative to clinical response in lungs of patients with COVID-19. These results demonstrate that expression of hACE2 via adenovirus delivery system sensitized the mouse to SARS-CoV-2 infection and resulted in the development of a mild COVID-19 phenotype, highlighting the immune and inflammatory host responses to SARS-CoV-2 infection. This rapidly deployable COVID-19 mouse model is useful for preclinical and pathogenesis studies of COVID-19.