Emerging Importance of Chemokine Receptor CXCR4 and Its Ligand in Liver Disease

Glioma Stem Cells as Promoter of Glioma Progression: A Systematic Review of Molecular Pathways and Targeted Therapies

Gliomas' aggressive nature and resistance to therapy make them a major problem in oncology. Gliomas continue to have dismal prognoses despite significant advancements in medical science, and traditional treatments like surgery, radiation (RT), and chemotherapy (CT) frequently prove to be ineffective. After glioma stem cells (GSCs) were discovered, the traditional view of gliomas as homogeneous masses changed. GSCs are essential for tumor growth, treatment resistance, and recurrence. These cells' distinct capacities for differentiation and self-renewal are changing our knowledge of the biology of gliomas. This systematic literature review aims to uncover the molecular mechanisms driving glioma progression associated with GSCs. The systematic review adhered to PRISMA guidelines, with a thorough literature search conducted on PubMed, Ovid MED-LINE, and Ovid EMBASE. The first literature search was performed on 1 March 2024, and the search was updated on 15 May 2024. Employing MeSH terms and Boolean operators, the search focused on molecular mechanisms associated with GCSs-mediated glioma progression. Inclusion criteria encompassed English language studies, preclinical studies, and clinical trials. A number of 957 papers were initially identified, of which 65 studies spanning from 2005 to 2024 were finally included in the review. The main GSC model distribution is arranged in decreasing order of frequency: U87: 20 studies (32.0%); U251: 13 studies (20.0%); A172: 4 studies (6.2%); and T98G: 2 studies (3.17%). From most to least frequent, the distribution of the primary GSC pathway is as follows: Notch: 8 studies (12.3%); STAT3: 6 studies (9.2%); Wnt/β-catenin: 6 studies (9.2%); HIF: 5 studies (7.7%); and PI3K/AKT: 4 studies (6.2%). The distribution of molecular effects, from most to least common, is as follows: inhibition of differentiation: 22 studies (33.8%); increased proliferation: 18 studies (27.7%); enhanced invasive ability: 15 studies (23.1%); increased self-renewal: 5 studies (7.7%); and inhibition of apoptosis: 3 studies (4.6%). This work highlights GSC heterogeneity and the dynamic interplay within the glioblastoma microenvironment, underscoring the need for a tailored approach. A few key pathways influencing GSC behavior are JAK/STAT3, PI3K/AKT, Wnt/β-catenin, and Notch. Therapy may target these pathways. This research urges more study to fill in knowledge gaps in the biology of GSCs and translate findings into useful treatment approaches that could improve GBM patient outcomes.

Prognostic role of the stromal cell derived factor-1 in patients with hepatitis B virus-related acute-on-chronic liver failure

BACKGROUND

Stromal cell derived factor-1 (SDF-1) plays a pivotal role in the recruitment of stem cells to injured livers. However, the changes of SDF-l in patients with hepatitis B virus (HBV)-related acute-on-chronic liver failure (ACLF) have yet to be elucidated.

AIM

To study the SDF-1 changes in patients with HBV-related ACLF.

METHODS

30 patients with HBV-related ACLF, 27 patients with chronic hepatitis B and 20 healthy individuals are involved in our study. The SDF-l mRNA expression in liver tissue was detected by quantitative real-time polymerase chain reaction. Immunohistochemical staining was performed to illustrate the expression of SDF-l, CXC receptor 4 (CXCR4) and Ki67. The serum SDF-l concentrations were also detected by enzyme-linked immunosorbent assays.

RESULTS

The expression of SDF-1 mRNA from ACLF patients was remarkably higher than that from other patients (both P < 0.05). The expression of SDF-l, CXCR4 and Ki67 from ACLF were the highest among the three groups (all P < 0.01). The serum SDF-l levels in ACLF patients were significantly lower than that in other patients (both P < 0.01). Moreover, in ACLF patients, the serum SDF-1 Levels were positively correlated with serum total bilirubin and international normalized ratio. In addition, the serum SDF-l levels in survival were significantly lower compared with the non-survivals (P < 0.05). The area under the curve for the serum SDF-1 level in predicting 28-d mortality was 0.722 (P < 0.05).

CONCLUSION

This study provides the SDF-1 changes in patients with HBV-related ACLF. The SDF-1 Level at admission may serve as a promising prognostic marker for predicting short-term prognosis.

ZNF469 is a profibrotic regulator of extracellular matrix in hepatic stellate cells

Activation of quiescent hepatic stellate cells (HSCs) into proliferative myofibroblasts drives extracellular cellular matrix (ECM) accumulation and liver fibrosis; nevertheless, the transcriptional network that promotes such a process is not completely understood. ZNF469 is a putative C2H2 zinc finger protein that may bind to specific genome sequences. It is found to be upregulated upon HSC activation; however, the molecular function of ZNF469 is completely unknown. Here, we show that knockdown of ZNF469 in primary human HSCs impaired proliferation, migration, and collagen production. Conversely, overexpression of ZNF469 in HSCs yielded the opposite results. Transforming growth factor-β 1 promoted expression of ZNF469 in a Smad3-dependent manner, where the binding of Smad3 was confirmed at the ZNF469 promoter. RNA sequencing data of ZNF469-knockdown HSCs revealed the ECM-receptor interaction, which provides structural and signaling support to cells, was the most affected pathway, and significant downregulation of various collagen and proteoglycan genes was observed. To investigate the function of ZNF469, we cloned a full-length open reading frame of ZNF469 with an epitope tag and identified a nuclear localization of the protein. Luciferase reporter and chromatin immunoprecipitation assays revealed the presence of ZNF469 at the promoter of ECM genes, supporting its function as a transcription factor. Analysis of human fibrotic and cirrhotic tissues showed increased expression of ZNF469 and a positive correlation between expression levels of ZNF469 and ECM genes. Moreover, this observation was similar in other fibrotic organs, including the heart, lung, and skin, suggesting that myofibroblasts from various origins generally require ZNF469 to promote ECM production. Together, this study is the first to reveal the role of ZNF469 as a profibrotic factor in HSCs and suggests ZNF469 as a novel target for antifibrotic therapy.

Hepatocellular carcinoma (HCC) tumor microenvironment is more suppressive than colorectal cancer liver metastasis (CRLM) tumor microenvironment

BACKGROUND AND PURPOSE

While HCC is an inflammation-associated cancer, CRLM develops on permissive healthy liver microenvironment. To evaluate the immune aspects of these two different environments, peripheral blood-(PB), peritumoral-(PT) and tumoral tissues-(TT) from HCC and CRLM patients were evaluated.

METHODS

40 HCC and 34 CRLM were enrolled and freshly TT, PT and PB were collected at the surgery. PB-, PT- and TT-derived CD4+CD25+ Tregs, M/PMN-MDSC and PB-derived CD4+CD25- T-effector cells (Teffs) were isolated and characterized. Tregs' function was also evaluated in the presence of the CXCR4 inhibitor, peptide-R29, AMD3100 or anti-PD1. RNA was extracted from PB/PT/TT tissues and tested for FOXP3, CXCL12, CXCR4, CCL5, IL-15, CXCL5, Arg-1, N-cad, Vim, CXCL8, TGFβ and VEGF-A expression.

RESULTS

In HCC/CRLM-PB, higher number of functional Tregs, CD4+CD25hiFOXP3+ was detected, although PB-HCC Tregs exert a more suppressive function as compared to CRLM Tregs. In HCC/CRLM-TT, Tregs were highly represented with activated/ENTPD-1+Tregs prevalent in HCC. As compared to CRLM, HCC overexpressed CXCR4 and N-cadherin/vimentin in a contest rich in arginase and CCL5. Monocytic MDSCs were highly represented in HCC/CRLM, while high polymorphonuclear MDSCs were detected only in HCC. Interestingly, the function of CXCR4-PB-Tregs was impaired in HCC/CRLM by the CXCR4 inhibitor R29.

CONCLUSION

In HCC and CRLM, peripheral blood, peritumoral and tumoral tissues Tregs are highly represented and functional. Nevertheless, HCC displays a more immunosuppressive TME due to Tregs, MDSCs, intrinsic tumor features (CXCR4, CCL5, arginase) and the contest in which it develops. As CXCR4 is overexpressed in HCC/CRLM tumor/TME cells, CXCR4 inhibitors may be considered for double hit therapy in liver cancer patients.

HIV and gp120-induced lipid droplets loss in hepatic stellate cells contribute to profibrotic profile

Liver fibrosis is the excessive accumulation of extracellular matrix proteins, primarily collagen, in response to liver injury caused by chronic liver diseases. HIV infection accelerates the progression of liver fibrosis in patients co-infected with HCV or HBV compared to those who are only mono-infected. The early event in the progression of liver fibrosis involves the activation of hepatic stellate cells (HSCs), which entails the loss of lipid droplets (LD) to fuel the production of extracellular matrix components crucial for liver tissue healing. Thus, we are examining the mechanism by which HIV stimulates the progression of liver fibrosis. HIV-R5 tropic infection was unable to induce the expression of TGF-β, collagen deposition, α-smooth muscle actin (α-SMA), and cellular proliferation. However, this infection induced the secretion of the profibrogenic cytokine IL-6 and the loss of LD. This process involved the participation of peroxisome proliferator-activated receptor (PPAR)-α and an increase in lysosomal acid lipase (LAL), along with the involvement of Microtubule-associated protein 1 A/1B-light chain 3 (LC3), strongly suggesting that LD loss could occur through acid lipolysis. These phenomena were mimicked by the gp120 protein from the R5 tropic strain of HIV. Preincubation of HSCs with the CCR5 receptor antagonist, TAK-779, blocked gp120 activity. Additionally, experiments performed with pseudotyped-HIV revealed that HIV replication could also contribute to LD loss. These results demonstrate that the cross-talk between HSCs and HIV involves a series of interactions that help explain some of the mechanisms involved in the exacerbation of liver damage observed in co-infected individuals.

Unraveling the complexities of fibrosis and ductular reaction in liver disease: pathogenesis, mechanisms, and therapeutic insights

Ductular reaction and fibrosis are hallmarks of many liver diseases including primary sclerosing cholangitis, primary biliary cholangitis, biliary atresia, alcoholic liver disease, and metabolic dysfunction-associated steatotic liver disease/metabolic dysfunction-associated steatohepatitis. Liver fibrosis is the accumulation of extracellular matrix often caused by excess collagen deposition by myofibroblasts. Ductular reaction is the proliferation of bile ducts (which are composed of cholangiocytes) during liver injury. Many other cells including hepatic stellate cells, hepatocytes, hepatic progenitor cells, mesenchymal stem cells, and immune cells contribute to ductular reaction and fibrosis by either directly or indirectly interacting with myofibroblasts and cholangiocytes. This review summarizes the recent findings in cellular links between ductular reaction and fibrosis in numerous liver diseases.

Association of HBsAg levels with differential gene expression in NK, CD8 T, and memory B cells in treated patients with chronic HBV

Background & Aims

HBsAg secretion may impact immune responses to chronic HBV infection. Thus, therapeutic approaches to suppress HBsAg production are being investigated. Our study aims to examine the immunomodulatory effects of high and low levels of circulating HBsAg and thereby improve our understanding of anti-HBV immunity.

Methods

An optimized 10x Genomics single-cell RNA sequencing workflow was applied to blood samples and liver fine-needle aspirates from 18 patients undergoing tenofovir/entecavir (NUC) treatment for chronic HBV infection. They were categorized based on their HBsAg levels: high (920-12,447 IU/ml) or low (1-100 IU/ml). Cluster frequencies, differential gene expression, and phenotypes were analyzed.

Results

In the blood of HBV-infected patients on NUC, the proportion of KLRC2+ "adaptive" natural killer (NK) cells was significantly lower in the HBsAg-high group and, remarkably, both KLRC2+ NK and KLRG1+ CD8 T cells display enrichment of lymphocyte activation-associated gene sets in the HBsAg-low group. High levels of HBsAg were associated with mild immune activation in the liver. However, no suppression of liver-resident CXCR6+ NCAM1+ NK or CXCR6+ CD69+ CD8 T cells was detected, while memory B cells showed signs of activation in both the blood and liver.

Conclusions

Among NUC-treated patients, we observed a minimal impact of HBsAg on leukocyte populations in the blood and liver. However, for the first time, we found that HBsAg has distinct effects, restricted to NK-, CD8 T-, and memory B-cell subsets, in the blood and liver. Our findings are highly relevant for current clinical studies evaluating treatment strategies aimed at suppressing HBsAg production and reinvigorating immunity to HBV.

Impact and implications

This study provides unique insight into the impact of HBsAg on gene expression levels of immune cell subsets in the blood and liver, particularly in the context of NUC-treated chronic HBV infection. It holds significant relevance for current and future clinical studies evaluating treatment strategies aimed at suppressing HBsAg production and reinvigorating immunity to HBV. Our findings raise questions about the effectiveness of such treatment strategies and challenge the previously hypothesized immunomodulatory effects of HBsAg on immune responses against HBV.

p53R245W Mutation Fuels Cancer Initiation and Metastases in NASH-driven Liver Tumorigenesis

Obesity is a significant global health concern. Non-alcoholic fatty liver disease and non-alcoholic steatohepatitis (NASH) are common risk factors for hepatocellular carcinoma (HCC) and are closely associated with metabolic comorbidities, including obesity and diabetes. The TP53 tumor suppressor is the most frequently mutated gene in liver cancers, with half of these alterations being missense mutations. These mutations produce highly abundant proteins in cancer cells which have both inhibitory effects on wildtype (WT) p53, and gain-of-function (GOF) activities that contribute to tumor progression. A Western diet increases p53 activity in the liver. To elucidate the functional consequences of Trp53 mutations in a NASH-driven liver tumorigenesis model, we generated somatic mouse models with Trp53 deletion or the missense hotspot mutant p53R245W only in hepatocytes and placed mice on a high-fat, choline-deficient diet. p53R245W in the presence of diet increased fatty liver, compensatory proliferation in the liver parenchyma, and enriched genes of tumor-promoting pathways such as KRAS signaling, MYC, and epithelial-mesenchymal transition when compared with controls in the premalignant liver. Moreover, p53R245W suppressed transcriptional activity of WT p53 in the liver in vivo under metabolic challenges, and shortened survival and doubling of HCC incidence as compared with control heterozygous mice. Complete loss of Trp53 also significantly accelerated liver tumor incidence and lowered time-to-tumor development compared with WT controls. p53R245W GOF properties increased carcinoma initiation, fueled mixed hepatocholangial carcinoma incidence, and tripled metastatic disease. Collectively, our in vivo studies indicate that p53R245W has stronger tumor promoting activities than Trp53 loss in the context of NASH.

SIGNIFICANCE

Using somatic NASH-driven mouse models with p53 deletion or mutant p53R245W only in hepatocytes, we discovered that p53R245W increased carcinoma initiation, fueled hepatocholangial carcinoma incidence, and tripled metastases.

Multiscale integrative analyses unveil immune-related diagnostic signature for the progression of MASLD

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a chronic liver disease prevalent worldwide, with an increasing incidence associated with obesity, diabetes, and metabolic syndrome. The progression of MASLD to metabolic dysfunction-associated steatohepatitis (MASH) poses a pressing health concern, highlighting the significance of accurately identifying MASLD and its progression to MASH as a primary challenge in the field. In this study, a systematic integration of 66 immune cell types was conducted. Comprehensive analyses were performed on bulk, single-cell RNA-Seq, and clinical data to investigate the immune cell types implicated in MASLD progression thoroughly. Multiple approaches, including immune infiltration, gene expression trend analysis, weighted gene coexpression network analysis, and 4 machine learning algorithms, were used to examine the dynamic changes in genes and immune cells during MASLD progression. C-X-C motif chemokine receptor 4 and dedicator of cytokinesis 8 have been identified as potential diagnostic biomarkers for MASLD progression. Furthermore, cell communication analysis at the single-cell level revealed that the involvement of C-X-C motif chemokine receptor 4 and dedicator of cytokinesis 8 in MASLD progression is mediated through their influence on T cells. Overall, our study identified vital immune cells and a 2-gene diagnostic signature for the progression of MASLD, providing a new perspective on the diagnosis and immune-related molecular mechanisms of MASLD. These findings have important implications for developing innovative diagnostic tools and therapies for MASLD.

Hepatic inflammatory responses in liver fibrosis

Chronic liver diseases such as nonalcoholic fatty liver disease (NAFLD) or viral hepatitis are characterized by persistent inflammation and subsequent liver fibrosis. Liver fibrosis critically determines long-term morbidity (for example, cirrhosis or liver cancer) and mortality in NAFLD and nonalcoholic steatohepatitis (NASH). Inflammation represents the concerted response of various hepatic cell types to hepatocellular death and inflammatory signals, which are related to intrahepatic injury pathways or extrahepatic mediators from the gut-liver axis and the circulation. Single-cell technologies have revealed the heterogeneity of immune cell activation concerning disease states and the spatial organization within the liver, including resident and recruited macrophages, neutrophils as mediators of tissue repair, auto-aggressive features of T cells as well as various innate lymphoid cell and unconventional T cell populations. Inflammatory responses drive the activation of hepatic stellate cells (HSCs), and HSC subsets, in turn, modulate immune mechanisms via chemokines and cytokines or transdifferentiate into matrix-producing myofibroblasts. Current advances in understanding the pathogenesis of inflammation and fibrosis in the liver, mainly focused on NAFLD or NASH owing to the high unmet medical need, have led to the identification of several therapeutic targets. In this Review, we summarize the inflammatory mediators and cells in the diseased liver, fibrogenic pathways and their therapeutic implications.

Correlation between SDF-1α, CD34 positive hematopoietic stem cells and CXCR4 expression with liver fibrosis in CCl4 rat model

BACKGROUND

One of the most frequent disorders is liver fibrosis. An improved understanding of the different events during the process of liver fibrosis & its reversibility could be helpful in its staging and in finding potential therapeutic agents.

AIM

The goal of this research was to evaluate the relationship among CD34 + HPSCs, SDF-1α, and CXCR4 receptor expression with the percentage of the area of hepatic fibrosis.

MATERIALS AND METHODS

Thirty-six male Sprague-Dawley rats were separated into the control group, liver injury group & spontaneous reversion group. The liver injury was induced by using 2 ml/kg CCl4 twice a week. Flow cytometric examination of CD34 + cells in the blood & liver was performed. Bone marrow & liver samples were taken for evaluation of the SDF-1α mRNA by PCR. Liver specimens were stained for histopathological and CXCR4 immuno-expression evaluation.

RESULTS

In the liver injury group, the hepatic enzymes, fibrosis area percentage, CXCR4 receptor expression in the liver, CD34 + cells in the blood and bone marrow & the level SDF-1α in the liver and its concentration gradient were statistically significantly elevated with the progression of the liver fibrosis. On the contrary, SDF-1α in the bone marrow was statistically significantly reduced with the development of liver fibrosis. During the spontaneous reversion group, all the studied parameters apart from SDF-1α in the bone marrow were statistically substantially decreased compared with the liver injury group. We found a statistically substantial positive correlation between fibrosis area and all of the following: liver enzymes, CXCR4 receptor expression in the liver, CD34 + cells in the blood and liver, and SDF- 1α in the liver and its concentration gradient. In conclusion, in CCl4 rat model, the fibrosis area is significantly correlated with many parameters in the blood, bone marrow, and liver, which can be used during the process of follow-up during the therapeutic interventions.

Isolation, culture, and delivery considerations for the use of mesenchymal stem cells in potential therapies for acute liver failure

Acute liver failure (ALF) is a high-mortality syndrome for which liver transplantation is considered the only effective treatment option. A shortage of donor organs, high costs and surgical complications associated with immune rejection constrain the therapeutic effects of liver transplantation. Recently, mesenchymal stem cell (MSC) therapy was recognized as an alternative strategy for liver transplantation. Bone marrow mesenchymal stem cells (BMSCs) have been used in clinical trials of several liver diseases due to their ease of acquisition, strong proliferation ability, multipotent differentiation, homing to the lesion site, low immunogenicity and anti-inflammatory and antifibrotic effects. In this review, we comprehensively summarized the harvest and culture expansion strategies for BMSCs, the development of animal models of ALF of different aetiologies, the critical mechanisms of BMSC therapy for ALF and the challenge of clinical application.

Comprehensive Strategy for Identifying Extracellular Vesicle Surface Proteins as Biomarkers for Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a liver disorder that has become a global health concern due to its increasing prevalence. There is a need for reliable biomarkers to aid in the diagnosis and prognosis of NAFLD. Extracellular vesicles (EVs) are promising candidates in biomarker discovery, as they carry proteins that reflect the pathophysiological state of the liver. In this review, we developed a list of EV proteins that could be used as diagnostic biomarkers for NAFLD. We employed a multi-step strategy that involved reviewing and comparing various sources of information. Firstly, we reviewed papers that have studied EVs proteins as biomarkers in NAFLD and papers that have studied circulating proteins as biomarkers in NAFLD. To further identify potential candidates, we utilized the EV database Vesiclepedia.org to qualify each protein. Finally, we consulted the Human Protein Atlas to search for candidates' localization, focusing on membrane proteins. By integrating these sources of information, we developed a comprehensive list of potential EVs membrane protein biomarkers that could aid in diagnosing and monitoring NAFLD. In conclusion, our multi-step strategy for identifying EV-based protein biomarkers for NAFLD provides a comprehensive approach that can also be applied to other diseases. The protein candidates identified through this approach could have significant implications for the development of non-invasive diagnostic tests for NAFLD and improve the management and treatment of this prevalent liver disorder.

The case for FAT10 as a novel target in fatty liver diseases

Human leukocyte antigen F locus adjacent transcript 10 (FAT10) is a ubiquitin-like protein that targets proteins for degradation. TNFα and IFNγ upregulate FAT10, which increases susceptibility to inflammation-driven diseases like nonalcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), and hepatocellular carcinoma (HCC). It is well established that inflammation contributes to fatty liver disease, but how inflammation contributes to upregulation and what genes are involved is still poorly understood. New evidence shows that FAT10 plays a role in mitophagy, autophagy, insulin signaling, insulin resistance, and inflammation which may be directly associated with fatty liver disease development. This review will summarize the current literature regarding FAT10 role in developing liver diseases and potential therapeutic targets for nonalcoholic/alcoholic fatty liver disease and hepatocellular carcinoma.

Endothelial Cell Dysfunction and Nonalcoholic Fatty Liver Disease (NAFLD): A Concise Review

Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases worldwide. It is strongly associated with obesity, type 2 diabetes (T2DM), and other metabolic syndrome features. Reflecting the underlying pathogenesis and the cardiometabolic disorders associated with NAFLD, the term metabolic (dysfunction)-associated fatty liver disease (MAFLD) has recently been proposed. Indeed, over the past few years, growing evidence supports a strong correlation between NAFLD and increased cardiovascular disease (CVD) risk, independent of the presence of diabetes, hypertension, and obesity. This implies that NAFLD may also be directly involved in the pathogenesis of CVD. Notably, liver sinusoidal endothelial cell (LSEC) dysfunction appears to be implicated in the progression of NAFLD via numerous mechanisms, including the regulation of the inflammatory process, hepatic stellate activation, augmented vascular resistance, and the distortion of microcirculation, resulting in the progression of NAFLD. Vice versa, the liver secretes inflammatory molecules that are considered pro-atherogenic and may contribute to vascular endothelial dysfunction, resulting in atherosclerosis and CVD. In this review, we provide current evidence supporting the role of endothelial cell dysfunction in the pathogenesis of NAFLD and NAFLD-associated atherosclerosis. Endothelial cells could thus represent a "golden target" for the development of new treatment strategies for NAFLD and its comorbid CVD.

Recovered Hepatocytes Promote Macrophage Apoptosis through CXCR4 after Acetaminophen-Induced Liver Injury in Mice

Acetaminophen (APAP) overdose is the main cause of acute liver failure in Western countries. The mechanism of APAP hepatotoxicity is associated with centrilobular necrosis which initiates infiltration of neutrophils, monocytes, and other leukocytes to the area of necrosis. While it has been recognized that this infiltration of immune cells plays a critical role in promoting liver repair, mechanism of immune cell clearance that is important for resolution of inflammation and the return to normal homeostasis are not well characterized. CXCR4 is a chemokine receptor expressed on hepatocytes as well as neutrophils, monocytes, and hematopoietic stem cells. CXCR4 function is dependent on its selective expression on different cell types and thus can vary depending on the pathophysiology. This study aimed to investigate the crosstalk between hepatocytes and macrophages through CXCR4 to promote macrophage apoptosis after APAP overdose. C57BL/6J mice were subjected to APAP overdose (300 mg/kg). Flow cytometry and immunohistochemistry were used to determine the mode of cell death of macrophages and expression pattern of CXCR4 during the resolution phase of APAP hepatotoxicity. The impact of CXCR4 in regulation of macrophage apoptosis and liver recovery was assessed after administration of a monoclonal antibody against CXCR4. RNAseq analysis was performed on flow cytometry sorted CXCR4+ macrophages at 72 h to confirm the apoptotic cell death of macrophages. Our data indicate that the inflammatory response is resolved by recovering hepatocytes through induction of CXCR4 on macrophages, which triggers their cell death by apoptosis at the end of the recovery phase.

Nanobodies in the limelight: Multifunctional tools in the fight against viruses

Antibodies are natural antivirals generated by the vertebrate immune system in response to viral infection or vaccination. Unsurprisingly, they are also key molecules in the virologist's molecular toolbox. With new developments in methods for protein engineering, protein functionalization and application, smaller antibody-derived fragments are moving in focus. Among these, camelid-derived nanobodies play a prominent role. Nanobodies can replace full-sized antibodies in most applications and enable new possible applications for which conventional antibodies are challenging to use. Here we review the versatile nature of nanobodies, discuss their promise as antiviral therapeutics, for diagnostics, and their suitability as research tools to uncover novel aspects of viral infection and disease.