The life-saving benefit of dexamethasone in severe COVID-19 is linked to a reversal of monocyte dysregulation.

Dexamethasone is a life-saving treatment for severe COVID-19, yet its mechanism of action is unknown, and many patients deteriorate or die despite timely treatment initiation. Here, we identify dexamethasone treatment-induced cellular and molecular changes associated with improved survival in COVID-19 patients. We observed a reversal of transcriptional hallmark signatures in monocytes associated with severe COVID-19 and the induction of a monocyte substate characterized by the expression of glucocorticoid-response genes. These molecular responses to dexamethasone were detected in circulating and pulmonary monocytes, and they were directly linked to survival. Monocyte single-cell RNA sequencing (scRNA-seq)-derived signatures were enriched in whole blood transcriptomes of patients with fatal outcome in two independent cohorts, highlighting the potential for identifying non-responders refractory to dexamethasone. Our findings link the effects of dexamethasone to specific immunomodulation and reversal of monocyte dysregulation, and they highlight the potential of single-cell omics for monitoring in vivo target engagement of immunomodulatory drugs and for patient stratification for precision medicine approaches.

M cell maturation and cDC activation determine the onset of adaptive immune priming in the neonatal Peyer's patch.

Early-life immune development is critical to long-term host health. However, the mechanisms that determine the pace of postnatal immune maturation are not fully resolved. Here, we analyzed mononuclear phagocytes (MNPs) in small intestinal Peyer's patches (PPs), the primary inductive site of intestinal immunity. Conventional type 1 and 2 dendritic cells (cDC1 and cDC2) and RORgt+ antigen-presenting cells (RORgt+ APC) exhibited significant age-dependent changes in subset composition, tissue distribution, and reduced cell maturation, subsequently resulting in a lack in CD4+ T cell priming during the postnatal period. Microbial cues contributed but could not fully explain the discrepancies in MNP maturation. Type I interferon (IFN) accelerated MNP maturation but IFN signaling did not represent the physiological stimulus. Instead, follicle-associated epithelium (FAE) M cell differentiation was required and sufficient to drive postweaning PP MNP maturation. Together, our results highlight the role of FAE M cell differentiation and MNP maturation in postnatal immune development.

Sublethal necroptosis signaling promotes inflammation and liver cancer.

It is currently not well known how necroptosis and necroptosis responses manifest in vivo. Here, we uncovered a molecular switch facilitating reprogramming between two alternative modes of necroptosis signaling in hepatocytes, fundamentally affecting immune responses and hepatocarcinogenesis. Concomitant necrosome and NF-κB activation in hepatocytes, which physiologically express low concentrations of receptor-interacting kinase 3 (RIPK3), did not lead to immediate cell death but forced them into a prolonged "sublethal" state with leaky membranes, functioning as secretory cells that released specific chemokines including CCL20 and MCP-1. This triggered hepatic cell proliferation as well as activation of procarcinogenic monocyte-derived macrophage cell clusters, contributing to hepatocarcinogenesis. In contrast, necrosome activation in hepatocytes with inactive NF-κB-signaling caused an accelerated execution of necroptosis, limiting alarmin release, and thereby preventing inflammation and hepatocarcinogenesis. Consistently, intratumoral NF-κB-necroptosis signatures were associated with poor prognosis in human hepatocarcinogenesis. Therefore, pharmacological reprogramming between these distinct forms of necroptosis may represent a promising strategy against hepatocellular carcinoma.

Acquisition of epithelial plasticity in human chronic liver disease.

For many adult human organs, tissue regeneration during chronic disease remains a controversial subject. Regenerative processes are easily observed in animal models, and their underlying mechanisms are becoming well characterized1-4, but technical challenges and ethical aspects are limiting the validation of these results in humans. We decided to address this difficulty with respect to the liver. This organ displays the remarkable ability to regenerate after acute injury, although liver regeneration in the context of recurring injury remains to be fully demonstrated. Here we performed single-nucleus RNA sequencing (snRNA-seq) on 47 liver biopsies from patients with different stages of metabolic dysfunction-associated steatotic liver disease to establish a cellular map of the liver during disease progression. We then combined these single-cell-level data with advanced 3D imaging to reveal profound changes in the liver architecture. Hepatocytes lose their zonation and considerable reorganization of the biliary tree takes place. More importantly, our study uncovers transdifferentiation events that occur between hepatocytes and cholangiocytes without the presence of adult stem cells or developmental progenitor activation. Detailed analyses and functional validations using cholangiocyte organoids confirm the importance of the PI3K-AKT-mTOR pathway in this process, thereby connecting this acquisition of plasticity to insulin signalling. Together, our data indicate that chronic injury creates an environment that induces cellular plasticity in human organs, and understanding the underlying mechanisms of this process could open new therapeutic avenues in the management of chronic diseases.

Auto-aggressive CXCR6+ CD8 T cells cause liver immune pathology in NASH.

Nonalcoholic steatohepatitis (NASH) is a manifestation of systemic metabolic disease related to obesity, and causes liver disease and cancer1,2. The accumulation of metabolites leads to cell stress and inflammation in the liver3, but mechanistic understandings of liver damage in NASH are incomplete. Here, using a preclinical mouse model that displays key features of human NASH (hereafter, NASH mice), we found an indispensable role for T cells in liver immunopathology. We detected the hepatic accumulation of CD8 T cells with phenotypes that combined tissue residency (CXCR6) with effector (granzyme) and exhaustion (PD1) characteristics. Liver CXCR6+ CD8 T cells were characterized by low activity of the FOXO1 transcription factor, and were abundant in NASH mice and in patients with NASH. Mechanistically, IL-15 induced FOXO1 downregulation and CXCR6 upregulation, which together rendered liver-resident CXCR6+ CD8 T cells susceptible to metabolic stimuli (including acetate and extracellular ATP) and collectively triggered auto-aggression. CXCR6+ CD8 T cells from the livers of NASH mice or of patients with NASH had similar transcriptional signatures, and showed auto-aggressive killing of cells in an MHC-class-I-independent fashion after signalling through P2X7 purinergic receptors. This killing by auto-aggressive CD8 T cells fundamentally differed from that by antigen-specific cells, which mechanistically distinguishes auto-aggressive and protective T cell immunity.

Gastric stem cells promote inflammation and gland remodeling in response to Helicobacter pylori via Rspo3-Lgr4 axis.

Helicobacter pylori is a pathogen that colonizes the stomach and causes chronic gastritis. Helicobacter pylori can colonize deep inside gastric glands, triggering increased R-spondin 3 (Rspo3) signaling. This causes an expansion of the "gland base module," which consists of self-renewing stem cells and antimicrobial secretory cells and results in gland hyperplasia. The contribution of Rspo3 receptors Lgr4 and Lgr5 is not well explored. Here, we identified that Lgr4 regulates Lgr5 expression and is required for H. pylori-induced hyperplasia and inflammation, while Lgr5 alone is not. Using conditional knockout mice, we reveal that R-spondin signaling via Lgr4 drives proliferation of stem cells and also induces NF-κB activity in the proliferative stem cells. Upon exposure to H. pylori, the Lgr4-driven NF-κB activation is responsible for the expansion of the gland base module and simultaneously enables chemokine expression in stem cells, resulting in gland hyperplasia and neutrophil recruitment. This demonstrates a connection between R-spondin-Lgr and NF-κB signaling that links epithelial stem cell behavior and inflammatory responses to gland-invading H. pylori.

Inhibition of LTßR signalling activates WNT-induced regeneration in lung.

Lymphotoxin ß-receptor (LTßR) signalling promotes lymphoid neogenesis and the development of tertiary lymphoid structures1,2, which are associated with severe chronic inflammatory diseases that span several organ systems3-6. How LTßR signalling drives chronic tissue damage particularly in the lung, the mechanism(s) that regulate this process, and whether LTßR blockade might be of therapeutic value have remained unclear. Here we demonstrate increased expression of LTßR ligands in adaptive and innate immune cells, enhanced non-canonical NF-κB signalling, and enriched LTßR target gene expression in lung epithelial cells from patients with smoking-associated chronic obstructive pulmonary disease (COPD) and from mice chronically exposed to cigarette smoke. Therapeutic inhibition of LTßR signalling in young and aged mice disrupted smoking-related inducible bronchus-associated lymphoid tissue, induced regeneration of lung tissue, and reverted airway fibrosis and systemic muscle wasting. Mechanistically, blockade of LTßR signalling dampened epithelial non-canonical activation of NF-κB, reduced TGFß signalling in airways, and induced regeneration by preventing epithelial cell death and activating WNT/ß-catenin signalling in alveolar epithelial progenitor cells. These findings suggest that inhibition of LTßR signalling represents a viable therapeutic option that combines prevention of tertiary lymphoid structures1 and inhibition of apoptosis with tissue-regenerative strategies.

C-C chemokine receptor type 7 (CCR7) regulates hepatic CD8 + T cell homeostasis and response to acute liver injury.

BACKGROUND AND AIMS: Acute liver failure (ALF) is a rare but life-threatening condition, and DILI, particularly acetaminophen toxicity, is the leading cause of ALF. Innate immune mechanisms further perpetuate liver injury, while the role of the adaptive immune system in DILI-related ALF is unclear. APPROACH AND RESULTS: We analyzed liver tissue from 2 independent patient cohorts with ALF and identified hepatic T cell infiltration as a prominent feature in human ALF. CD8 + T cells were characterized by zonation toward necrotic regions and an activated gene expression signature. In murine acetaminophen-induced liver injury, intravital microscopy revealed zonation of CD8 + but not CD4 + T cells at necrotic areas. Gene expression analysis exposed upregulated C-C chemokine receptor 7 (CCR7) and its ligand CCL21 in the liver as well as a broadly activated phenotype of hepatic CD8 + T cells. In 2 mouse models of ALF, Ccr7-/- mice had significantly aggravated early-phase liver damage. Functionally, CCR7 was not involved in the recruitment of CD8 + T cells, but regulated their activation profile potentially through egress to lymphatics. Ccr7-/- CD8 + T cells were characterized by elevated expression of activation, effector, and exhaustion profiles. Adoptive transfer revealed preferential homing of CCR7-deficient CD8 + T cells to the liver, and depletion of CD8 + T cells attenuated liver damage in mice. CONCLUSIONS: Our study demonstrates the involvement of the adaptive immune system in ALF in humans and mice. We identify the CCR7-CCL21 axis as an important regulatory pathway, providing downstream protection against T cell-mediated liver injury.

Delineating the heterogeneity of senescence-induced-functional alterations in hepatocytes.

BACKGROUND AND AIM: Cellular senescence of hepatocytes involves permanent cell cycle arrest, disrupted cellular bioenergetics, resistance to cell death, and the release of pro-inflammatory cytokines. This 'zombie-like' state perpetuates harmful effects on tissues and holds potential implications for liver disease progression. Remarkably, senescence exhibits heterogeneity, stemming from two crucial factors: the inducing stressor and the cell type. As such, our present study endeavors to characterize stressor-specific changes in senescence phenotype, its related molecular patterns, and cellular bioenergetics in primary mouse hepatocytes (PMH) and hepatocyte-derived liver organoids (HepOrgs). METHODS: PMH, isolated by collagenase-perfused mouse liver (C57B6/J; 18-23 weeks), were cultured overnight in William's E-medium supplemented with 2% FBS, L-glutamine, and hepatocyte growth supplements. HepOrgs were developed by culturing cells in a 3D matrix for two weeks. The senescence was induced by DNA damage (doxorubicin, cisplatin, and etoposide), oxidative stress (H2O2, and ethanol), and telomere inhibition (BIBR-1532), p53 activation (nutlin-3a), DNA methyl transferase inhibition (5-azacitidine), and metabolism inhibitors (galactosamine and hydroxyurea). SA-ß galactosidase activity, immunofluorescence, immunoblotting, and senescence-associated secretory phenotype (SASP), and cellular bioenergetics were used to assess the senescence phenotype. RESULTS: Each senescence inducer triggers a unique combination of senescence markers in hepatocytes. All senescence inducers, except hydroxyurea and ethanol, increased SA-ß galactosidase activity, the most commonly used marker for cellular senescence. Among the SASP factors, CCL2 and IL-10 were consistently upregulated, while Plasminogen activator inhibitor-1 exhibited global downregulation across all modes of senescence. Notably, DNA damage response was activated by DNA damage inducers. Cell cycle markers were most significantly reduced by doxorubicin, cisplatin, and galactosamine. Additionally, DNA damage-induced senescence shifted cellular bioenergetics capacity from glycolysis to oxidative phosphorylation. In HepOrgs exposed to senescence inducers, there was a notable increase in γH2A.X, p53, and p21 levels. Interestingly, while showing a similar trend, SASP gene expression in HepOrgs was significantly higher compared to PMH, demonstrating a several-fold increase. CONCLUSION: In our study, we demonstrated that each senescence inducer activates a unique combination of senescence markers in PMH. Doxorubicin demonstrated the highest efficacy in inducing senescence, followed by cisplatin and H2O2, with no impact on apoptosis. Each inducer prompted DNA damage response and mitochondrial dysfunction, independent of MAPK/AKT.

Overcoming Resistance to Immune Checkpoint Blockade in Liver Cancer with Combination Therapy: Stronger Together?

Primary liver cancer, represented mainly by hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (CCA), is one of the most common and deadliest tumors worldwide. While surgical resection or liver transplantation are the best option in early disease stages, these tumors often present in advanced stages and systemic treatment is required to improve survival time. The emergence of immune checkpoint inhibitor (ICI) therapy has had a positive impact especially on the treatment of advanced cancers, thereby establishing immunotherapy as part of first-line treatment in HCC and CCA. Nevertheless, low response rates reflect on the usually cold or immunosuppressed tumor microenvironment of primary liver cancer. In this review, we aim to summarize mechanisms of resistance leading to tumor immune escape with a special focus on the composition of tumor microenvironment in both HCC and CCA, also reflecting on recent important developments in ICI combination therapy. Furthermore, we discuss how combination of ICIs with established primary liver cancer treatments (e.g. multikinase inhibitors and chemotherapy) as well as more complex combinations with state-of-the-art therapeutic concepts may reshape the tumor microenvironment, leading to higher response rates and long-lasting antitumor immunity for primary liver cancer patients.

Intestinal retinol saturase is implicated in the development of obesity and epithelial homeostasis upon injury.

Retinol saturase (RetSat) is an oxidoreductase involved in lipid metabolism and the cellular sensitivity to peroxides. RetSat is highly expressed in metabolic organs like liver and adipose tissue and its global loss in mice increases body weight and adiposity. The regulation of RetSat expression and its function in the intestine are unexplored. Here, we show that RetSat is present in different segments of the digestive system, localizes to intestinal epithelial cells, and is upregulated by feeding mice high-fat diet (HFD). Intestine-specific RetSat deletion in adult mice did not affect nutrient absorption and energy homeostasis basally, but lowered body weight gain and fat mass of HFD-fed mice, potentially via increasing locomotor activity. Moreover, jejunal expression of genes related to ß-oxidation and cholesterol efflux were decreased and colonic cholesterol content reduced upon RetSat deletion. In colitis, which we show to downregulate intestinal RetSat expression in humans and mice, RetSat ablation improved epithelial architecture of the murine colon. Thus, intestinal RetSat expression is regulated by dietary interventions and inflammation, and its loss reduces weight gain upon HFD-feeding and alleviates epithelial damage upon injury.

Angiocrine signaling in sinusoidal homeostasis and liver diseases.

The hepatic sinusoids are composed of liver sinusoidal endothelial cells (LSECs), which are surrounded by hepatic stellate cells (HSCs) and contain liver-resident macrophages called Kupffer cells, and other patrolling immune cells. All these cells communicate with each other and with hepatocytes to maintain sinusoidal homeostasis and a spectrum of hepatic functions under healthy conditions. Sinusoidal homeostasis is disrupted by metabolites, toxins, viruses, and other pathological factors, leading to liver injury, chronic liver diseases, and cirrhosis. Alterations in hepatic sinusoids are linked to fibrosis progression and portal hypertension. LSECs are crucial regulators of cellular crosstalk within their microenvironment via angiocrine signaling. This review discusses the mechanisms by which angiocrine signaling orchestrates sinusoidal homeostasis, as well as the development of liver diseases. Here, we summarise the crosstalk between LSECs, HSCs, hepatocytes, cholangiocytes, and immune cells in health and disease and comment on potential novel therapeutic methods for treating liver diseases.

Cenicriviroc Lacked Efficacy to Treat Liver Fibrosis in Nonalcoholic Steatohepatitis: AURORA Phase III Randomized Study.

BACKGROUND AND AIMS: Cenicriviroc (CVC) is a novel, orally administered, chemokine receptor type 2 and 5 antagonist that showed antifibrotic potential in preclinical and phase IIb studies of nonalcoholic steatohepatitis (NASH). Herein, we report efficacy and safety results from the phase III study. METHODS: The AURORA (A Study for the Efficacy and Safety of CVC for the Treatment of Liver Fibrosis in Adults With NASH) study was a phase III, randomized, double-blind, placebo-controlled, 2-part study of patients with NASH and stage 2/3 liver fibrosis. Adults, 18-75 years of age, were randomized to CVC 150 mg or placebo once daily for 12 months (part 1) or 60 months (part 2). Liver biopsies were performed at screening, month 12, and early study discontinuation or termination. The primary efficacy endpoint was the proportion of patients with fibrosis improvement ≥1 stage without worsening of steatohepatitis at month 12 relative to screening. Adverse events were assessed throughout the study. RESULTS: A total of 1778 patients were randomized and discontinued (part 1: n = 1293; part 2: n = 485). In part 1, at month 12, a similar proportion of patients receiving CVC or placebo achieved the primary endpoint (22.3% vs 25.5%; odds ratio, 0.84; 95% confidence interval, 0.63-1.10; P = .21) and complete resolution of steatohepatitis without worsening of fibrosis (23.0% vs 27.2%; P = .21). The safety profile was generally comparable across treatment groups. CONCLUSIONS: This study did not demonstrate the efficacy of CVC for treating liver fibrosis assessed by histology in adults with NASH; however, CVC was safe and well tolerated in patients with NASH and liver fibrosis. (ClinicalTrials.gov, Number: NCT03028740).

Phenotypes of Metabolic Dysfunction-Associated Steatotic Liver Disease-Associated Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) typically develops as a consequence of liver cirrhosis, but HCC epidemiology has evolved drastically in recent years. Metabolic dysfunction-associated steatotic liver disease (MASLD), including metabolic dysfunction-associated steatohepatitis, has emerged as the most common chronic liver disease worldwide and a leading cause of HCC. A substantial proportion of MASLD-associated HCC (MASLD-HCC) also can develop in patients without cirrhosis. The specific pathways that trigger carcinogenesis in this context are not elucidated completely, and recommendations for HCC surveillance in MASLD patients are challenging. In the era of precision medicine, it is critical to understand the processes that define the profiles of patients at increased risk of HCC in the MASLD setting, including cardiometabolic risk factors and the molecular targets that could be tackled effectively. Ideally, defining categories that encompass key pathophysiological features, associated with tailored diagnostic and treatment strategies, should facilitate the identification of specific MASLD-HCC phenotypes. In this review, we discuss MASLD-HCC, including its epidemiology and health care burden, the mechanistic data promoting MASLD, metabolic dysfunction-associated steatohepatitis, and MASLD-HCC. Its natural history, prognosis, and treatment are addressed specifically, as the role of metabolic phenotypes of MASLD-HCC as a potential strategy for risk stratification. The challenges in identifying high-risk patients and screening strategies also are discussed, as well as the potential approaches for MASLD-HCC prevention and treatment.

Endoscopic Features of Post-COVID-19 Cholangiopathy and Its Management Using ERCP.

INTRODUCTION: Despite growing awareness of post-coronavirus disease 2019 (COVID-19) cholangiopathy as one of the most serious long-term gastrointestinal consequences of COVID-19, the endoscopic features of this disease are still poorly characterized. This study aimed to more precisely define its endoscopic features and to outline the role of endoscopic retrograde cholangiopancreatography (ERCP) in the management of this entity. METHODS: In this observational study, 46 patients with confirmed post-COVID-19 cholangiopathy were included. RESULTS: Based on the endoscopic features observed in 141 ERCP procedures, post-COVID-19 cholangiopathy can be classified as a variant of secondary sclerosing cholangitis in critically ill patients. It appeared early in the course of intensive care treatment of patients with COVID-19 (cholestasis onset 4.5 days after intubation, median). This form of cholangiopathy was more destructive than stricturing in nature and caused irreversible damage to the bile ducts. A centripetal pattern of intrahepatic bile duct destruction, the phenomenon of vanishing bile ducts, the absence of extrahepatic involvement, and the presence of intraductal biliary casts (85% of patients) were typical cholangiographic features of post-COVID-19 cholangiopathy. This cholangiopathy was often complicated by small peribiliary liver abscesses with isolation of Enterococcus faecium and Candida spp. in bile culture. The prognosis was dismal, with a 1-year liver transplantation-free survival rate of 44%. In particular, patients with peribiliary liver abscesses or destruction of the central bile ducts tended to have a poor prognosis (n.s.). As shown by multivariate analysis, bilirubin levels (on intensive care unit day 25-36) negatively correlated with liver transplantation-free survival (hazard ratio 1.08, P < 0.001). Interventional endoscopy with cast removal had a positive effect on cholestasis parameters (gamma-glutamyl transpeptidase, alkaline phosphatase, and bilirubin); approximately 60% of all individual values decreased. DISCUSSION: Gastrointestinal endoscopy makes an important contribution to the management of post-COVID-19 cholangiopathy. ERCP is not only of great diagnostic and prognostic value but also has therapeutic value and therefore remains indispensable.

Intubation Decision Based on Illness Severity and Mortality in COVID-19: An International Study.

OBJECTIVES: To evaluate the impact of intubation timing, guided by severity criteria, on mortality in critically ill COVID-19 patients, amidst existing uncertainties regarding optimal intubation practices. DESIGN: Prospective, multicenter, observational study conducted from February 1, 2020, to November 1, 2022. SETTING: Ten academic institutions in the United States and Europe. PATIENTS: Adults (≥ 18 yr old) confirmed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and hospitalized specifically for COVID-19, requiring intubation postadmission. Exclusion criteria included patients hospitalized for non-COVID-19 reasons despite a positive SARS-CoV-2 test. INTERVENTIONS: Early invasive mechanical ventilation (EIMV) was defined as intubation in patients with less severe organ dysfunction (Sequential Organ Failure Assessment [SOFA] < 7 or Pa o2 /F io2 ratio > 250), whereas late invasive mechanical ventilation (LIMV) was defined as intubation in patients with SOFA greater than or equal to 7 and Pa o2 /F io2 ratio less than or equal to 250. MEASUREMENTS AND MAIN RESULTS: The primary outcome was mortality within 30 days of hospital admission. Among 4464 patients, 854 (19.1%) required mechanical ventilation (mean age 60 yr, 61.7% male, 19.3% Black). Of those, 621 (72.7%) were categorized in the EIMV group and 233 (27.3%) in the LIMV group. Death within 30 days after admission occurred in 278 patients (42.2%) in the EIMV and 88 patients (46.6%) in the LIMV group ( p = 0.28). An inverse probability-of-treatment weighting analysis revealed a statistically significant association with mortality, with patients in the EIMV group being 32% less likely to die either within 30 days of admission (adjusted hazard ratio [HR] 0.68; 95% CI, 0.52-0.90; p = 0.008) or within 30 days after intubation irrespective of its timing from admission (adjusted HR 0.70; 95% CI, 0.51-0.90; p = 0.006). CONCLUSIONS: In severe COVID-19 cases, an early intubation strategy, guided by specific severity criteria, is associated with a reduced risk of death. These findings underscore the importance of timely intervention based on objective severity assessments.

Rationale of using the dual chemokine receptor CCR2/CCR5 inhibitor cenicriviroc for the treatment of COVID-19.

Coronavirus Disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has created a global pandemic infecting over 230 million people and costing millions of lives. Therapies to attenuate severe disease are desperately needed. Cenicriviroc (CVC), a C-C chemokine receptor type 5 (CCR5) and C-C chemokine receptor type 2 (CCR2) antagonist, an agent previously studied in advanced clinical trials for patients with HIV or nonalcoholic steatohepatitis (NASH), may have the potential to reduce respiratory and cardiovascular organ failures related to COVID-19. Inhibiting the CCR2 and CCR5 pathways could attenuate or prevent inflammation or fibrosis in both early and late stages of the disease and improve outcomes of COVID-19. Clinical trials using CVC either in addition to standard of care (SoC; e.g., dexamethasone) or in combination with other investigational agents in patients with COVID-19 are currently ongoing. These trials intend to leverage the anti-inflammatory actions of CVC for ameliorating the clinical course of COVID-19 and prevent complications. This article reviews the literature surrounding the CCR2 and CCR5 pathways, their proposed role in COVID-19, and the potential role of CVC to improve outcomes.

Fluorochrome-dependent specific changes in spectral profiles using different compensation beads or primary cells in full spectrum cytometry.

Full spectrum flow cytometry is a powerful tool for immune monitoring on a single-cell level and with currently available machines, panels of 40 or more markers per sample are possible. However, with an increased panel size, spectral unmixing issues arise, and appropriate single stain reference controls are required for accurate experimental results and to avoid unmixing errors. In contrast to conventional flow cytometry, full spectrum flow cytometry takes into account even minor differences in spectral signatures and requires the full spectrum of each fluorochrome to be identical in the reference control and the fully stained sample to ensure accurate and reliable results. In general, using the cells of interest is considered optimal, but certain markers may not be expressed at sufficient levels to generate a reliable positive control. In this case, compensation beads show some significant advantages as they bind a consistent amount of antibody independent of its specificity. In this study, we evaluated two types of manufactured compensation beads for use as reference controls for 30 of the most commonly used and commercially available fluorochromes in full spectrum cytometry and compared them to human and murine primary leukocytes. While most fluorochromes show the same spectral profile on beads and cells, we demonstrate that specific fluorochromes show a significantly different spectral profile depending on which type of compensation beads is used, and some fluorochromes should be used on cells exclusively. Here, we provide a list of important considerations when selecting optimal reference controls for full spectrum flow cytometry.

Gene-expression profiling of laser-dissected islets and studies in deficient mice reveal chemokines as differential driving force of type 1 diabetes.

Although type 1 diabetes (T1D) results from the autoimmune destruction of the insulin-producing ß-cells, its treatment is largely restricted to exogenous insulin administration. Only few therapies targeting the autoaggressive immune system have been introduced into clinical practice or are considered in clinical trials. Here, we provide a gene expression profile of the islet microenvironment obtained by laser-dissection microscopy in an inducible mouse model. Thereby, we have identified novel targets for immune intervention. Increased gene expression of most inflammatory proteins was apparent at day 10 after T1D induction and largely paralleled the observed degree of insulitis. We further focused on genes involved in leukocyte migration, including chemokines and their receptors. Besides the critical chemokine CXCL10, we found several other chemokines upregulated locally in temporary or chronic manner. Localization of the chemokine ligand/receptor pairs to the islet microenvironment has been confirmed by RNAscope. Interference with the CXCL16-CXCR6 and CX3CL1-CX3CR1 axes, but not the CCL5-CCR1/3/5 axis, resulted in reduced insulitis and lower T1D incidence. Further, we found that the receptors for the differentially expressed chemokines CXCL10, CXCL16 and CX3CL1 are distributed unevenly among islet autoantigen-specific T cells, which explains why the interference with just one chemokine axis cannot completely abrogate insulitis and T1D.

Therapeutic modulation of the liver immune microenvironment.

Inflammation is a hallmark of progressive liver diseases such as chronic viral or immune-mediated hepatitis, alcohol-associated liver disease, and NAFLD. Preclinical and clinical studies have provided robust evidence that cytokines and related cellular stress sensors in innate and adaptive immunity orchestrate hepatic disease processes. Unresolved inflammation and liver injury result in hepatic scarring, fibrosis, and cirrhosis, which may culminate in HCC. Liver diseases are accompanied by gut dysbiosis and a bloom of pathobionts, fueling hepatic inflammation. Anti-inflammatory strategies are extensively used to treat human immune-mediated conditions beyond the liver, while evidence for immunomodulatory therapies and cell therapy-based strategies in liver diseases is only emerging. The development and establishment of novel immunomodulatory therapies for chronic liver diseases has been dampened by several clinical challenges, such as invasive monitoring of therapeutic efficacy with liver biopsy in clinical trials and risk of DILI in several studies. Such aspects prevented advancements of novel medical therapies for chronic inflammatory liver diseases. New concepts modulating the liver immune environment are studied and eagerly awaited to improve the management of chronic liver diseases in the future.