Indirect action of tumor necrosis factor-alpha in liver injury during the CD8+ T cell response to an adeno-associated virus vector in mice

Unveiling the landscape of cytokine research in glioma immunotherapy: a scientometrics analysis

Background: Cytokines modulate the glioma tumor microenvironment, influencing occurrence, progression, and treatment response. Strategic cytokine application may improve glioma immunotherapy outcomes. Gliomas remain refractory to standard therapeutic modalities, but immunotherapy shows promise given the integral immunomodulatory roles of cytokines. However, systematic evaluation of cytokine glioma immunotherapy research is absent. Bibliometric mapping of the research landscape, recognition of impactful contributions, and elucidation of evolutive trajectories and hot topics has yet to occur, potentially guiding future efforts. Here, we analyzed the structure, evolution, trends, and hotspots of the cytokine glioma immunotherapy research field, subsequently focusing on avenues for future investigation. Methods: This investigation conducted comprehensive bibliometric analyses on a corpus of 1529 English-language publications, from 1 January 2000, to 4 October 2023, extracted from the Web of Science database. The study employed tools including Microsoft Excel, Origin, VOSviewer, CiteSpace, and the Bibliometrix R package, to systematically assess trends in publication, contributions from various countries, institutions, authors, and journals, as well as to examine literature co-citation and keyword distributions within the domain of cytokines for glioma immunotherapy. The application of these methodologies facilitated a detailed exploration of the hotspots, the underlying knowledge structure, and the developments in the field of cytokines for glioma immunotherapy. Results: This bibliometric analysis revealed an exponential growth in annual publications, with the United States, China, and Germany as top contributors. Reviews constituted 17% and research articles 83% of total publications. Analysis of keywords like "interleukin-13," "TGF-beta," and "dendritic cells" indicated progression from foundational cytokine therapies to sophisticated understanding of the tumor microenvironment and immune dynamics. Key research avenues encompassed the tumor microenvironment, epidermal growth factor receptor, clinical trials, and interleukin pathways. This comprehensive quantitative mapping of the glioma immunotherapy cytokine literature provides valuable insights to advance future research and therapeutic development. Conclusion: This study has identified remaining knowledge gaps regarding the role of cytokines in glioma immunotherapy. Future research will likely focus on the tumor microenvironment, cancer vaccines, epidermal growth factor receptor, and interleukin-13 receptor alpha 2. Glioma immunotherapy development will continue through investigations into resistance mechanisms, microglia and macrophage biology, and interactions within the complex tumor microenvironment.

Involvement of TLR4 in Acute Hepatitis Associated with Airway Infection of Murine γ-Herpesvirus 68

Extrahepatic viral infections are often accompanied by acute hepatitis, as evidenced by elevated serum liver enzymes and intrasinusoidal infiltration of CD8+ T cells, without direct infection of the liver. An example is infectious mononucleosis caused by primary infection with EBV. Previously, we demonstrated that airway infection of mice with murine γ-herpesvirus 68 (MHV68), a murine model of EBV, caused liver inflammation with elevated serum liver enzymes and intrahepatic infiltration of IFN-γ-producing CD8+ T cells and NK cells. Mechanistically, the expression of the CXCR3-ligand chemokines, which are commonly induced by IFN-γ and attract IFN-γ-producing Th1-type cells via CXCR3, was upregulated in the liver. Importantly, the liver inflammation was suppressed by oral neomycin, an intestine-impermeable aminoglycoside, suggesting an involvement of some products from the intestinal microbiota. In this study, we showed that the liver inflammation and the expression of the CXCR3-ligand chemokines in the liver were effectively ameliorated by i.p. administration of anti-TLR4 mAb or C34, a TLR4 blocker, as well as in TLR4-deficient mice. Conversely, intrarectal inoculation of Escherichia coli as an extraintestinal source of LPS aggravated liver inflammation in MHV68-infected mice with increased expression of the CXCR3-ligand chemokines in the liver. In contrast, the lung inflammation in MHV68-infected mice was not affected by oral neomycin, i.p. administration of C34, or TLR4 deficiency. Collectively, the LPS-TLR4 pathway plays a pivotal role in the liver inflammation of MHV68-infected mice at least in part by upregulating the CXCR3-ligand chemokines in the liver.

Inflammatory response to the ischaemia-reperfusion insult in the liver after major tissue trauma

BACKGROUND

Polytrauma is often accompanied by ischaemia-reperfusion injury to tissues and organs, and the resulting series of immune inflammatory reactions are a major cause of death in patients. The liver is one of the largest organs in the body, a characteristic that makes it the most vulnerable organ after multiple injuries. In addition, the liver is an important digestive organ that secretes a variety of inflammatory mediators involved in local as well as systemic immune inflammatory responses. Therefore, this review considers the main features of post-traumatic liver injury, focusing on the immuno-pathophysiological changes, the interactions between liver organs, and the principles of treatment deduced.

METHODS

We focus on the local as well as systemic immune response involving the liver after multiple injuries, with emphasis on the pathophysiological mechanisms.

RESULTS

An overview of the mechanisms underlying the pathophysiology of local as well as systemic immune responses involving the liver after multiple injuries, the latest research findings, and the current mainstream therapeutic approaches.

CONCLUSION

Cross-reactivity between various organs and cascade amplification effects are among the main causes of systemic immune inflammatory responses after multiple injuries. For the time being, the pathophysiological mechanisms underlying this interaction remain unclear. Future work will continue to focus on identifying potential signalling pathways as well as target genes and intervening at the right time points to prevent more severe immune inflammatory responses and promote better and faster recovery of the patient.

Understanding, predicting and achieving liver transplant tolerance: from bench to bedside

In the past 40 years, liver transplantation has evolved from a high-risk procedure to one that offers high success rates for reversal of liver dysfunction and excellent patient and graft survival. The liver is the most tolerogenic of transplanted organs; indeed, immunosuppressive therapy can be completely withdrawn without rejection of the graft in carefully selected, stable long-term liver recipients. However, in other recipients, chronic allograft injury, late graft failure and the adverse effects of anti-rejection therapy remain important obstacles to improved success. The liver has a unique composition of parenchymal and immune cells that regulate innate and adaptive immunity and that can promote antigen-specific tolerance. Although the mechanisms underlying liver transplant tolerance are not well understood, important insights have been gained into how the local microenvironment, hepatic immune cells and specific molecular pathways can promote donor-specific tolerance. These insights provide a basis for the identification of potential clinical biomarkers that might correlate with tolerance or rejection and for the development of novel therapeutic targets. Innovative approaches aimed at promoting immunosuppressive drug minimization or withdrawal include the adoptive transfer of donor-derived or recipient-derived regulatory immune cells to promote liver transplant tolerance. In this Review, we summarize and discuss these developments and their implications for liver transplantation.

Panaxynol from Saposhnikovia diviaricata exhibits a hepatoprotective effect against lipopolysaccharide + D-Gal N induced acute liver injury by inhibiting Nf-κB/IκB-α and activating Nrf2/HO-1 signaling pathways

We investigated the mechanism of action of panaxynol (PAL) extract from the root of Saposhnikovia diviaricata (Turcz.) Schischk for treating acute liver injury caused by lipopolysaccharide (LPS) and D-galactosamine (D-Gal N) in mice. A mouse model of acute liver failure induced by LPS/D-Gal N was established. Mice were divided randomly into three equal groups: control group, LPS/D-Gal N group and PAL group. After seven days of continuous PAL administration, all animals except controls were injected with 50 μg/kg LPS and 800 mg/kg D-Gal N; blood and liver samples were collected after 8 h. Compared to the LPS/D-Gal N group, the levels of catalase, glutathione and superoxide dismutase were increased in the liver of the PAL group. The inflammatory response index indicated that PAL attenuated LPS/D Gal N-induced liver pathological injury and decreased levels of hepatic malondialdehyde, serum alanine aminotransferase, aspartate transaminase, tumor necrosis factor-α, and interleukins 1β and 6. PAL also inhibited LPS/D-Gal N induced nuclear factor-kappa B (Nf-κB), inhibitor kappa B-α (IκB-α) activation, and up-regulated Nrf2 and heme oxygenase-1 (HO-1) expression. PAL can prevent LPS/D-Gal N induced acute liver injury by activating Nrf2/HO-1 to stimulate antioxidant defense and inhibit the IkB-α/NF-κB signaling pathway.

Markers of liver regeneration-the role of growth factors and cytokines: a systematic review

BACKGROUND

Post-hepatectomy liver failure contributes significantly to postoperative mortality after liver resection. The prediction of the individual risk for liver failure is challenging. This review aimed to provide an overview of cytokine and growth factor triggered signaling pathways involved in liver regeneration after resection.

METHODS

MEDLINE and Cochrane databases were searched without language restrictions for articles from the time of inception of the databases till March 2019. All studies with comparative data on the effect of cytokines and growth factors on liver regeneration in animals and humans were included.

RESULTS

Overall 3.353 articles comprising 40 studies involving 1.498 patients and 101 animal studies were identified and met the inclusion criteria. All included trials on humans were retrospective cohort/observational studies. There was substantial heterogeneity across all included studies with respect to the analyzed cytokines and growth factors and the described endpoints.

CONCLUSION

High-level evidence on serial measurements of growth factors and cytokines in blood samples used to predict liver regeneration after resection is still lacking. To address the heterogeneity of patients and potential markers, high throughput serial analyses may offer a method to predict an individual's regenerative potential in the future.

Plasmodium cellular effector mechanisms and the hepatic microenvironment

Plasmodium falciparum malaria remains one of the most serious health problems globally. Immunization with attenuated parasites elicits multiple cellular effector mechanisms capable of eliminating Plasmodium liver stages. However, malaria liver stage (LS) immunity is complex and the mechanisms effector T cells use to locate the few infected hepatocytes in the large liver in order to kill the intracellular LS parasites remain a mystery to date. Here, we review our current knowledge on the behavior of CD8 effector T cells in the hepatic microvasculature, in malaria and other hepatic infections. Taking into account the unique immunological and lymphogenic properties of the liver, we discuss whether classical granule-mediated cytotoxicity might eliminate infected hepatocytes via direct cell contact or whether cytokines might operate without cell–cell contact and kill Plasmodium LSs at a distance. A thorough understanding of the cellular effector mechanisms that lead to parasite death hence sterile protection is a prerequisite for the development of a successful malaria vaccine to protect the 40% of the world’s population currently at risk of Plasmodium infection.

Inhibition of tumor necrosis factor alpha reduces the outgrowth of hepatic micrometastasis of colorectal tumors in a mouse model of liver ischemia-reperfusion injury

Background

Patients with colorectal cancer (CRC) often develop liver metastases, in which case surgery is considered the only potentially curative treatment option. However, liver surgery is associated with a risk of ischemia-reperfusion (IR) injury, which is thought to promote the growth of colorectal liver metastases. The influence of IR-induced tumor necrosis factor alpha (TNF-α) elevation in the process still is unknown. To investigate the role of TNF-α in the growth of pre-existing micrometastases in the liver following IR, we used a mouse model of colorectal liver metastases. In this model, mice received IR treatment seven days after intrasplenic injections of colorectal CT26 cells. Prior to IR treatment, either TNF-α blocker Enbrel or low-dose TNF-α, which could inhibit IR-induced TNF-α elevation, was administered by intraperitoneal injection.

Results

Hepatic IR treatment significantly promoted CT26 tumor growth in the liver, but either Enbrel or low-dose TNF-α pretreatment reversed this trend. Further studies showed that the CT26 + IR group prominently increased the levels of ALT and AST, liver necrosis, inflammatory infiltration and the expressions of hepatic IL-6, MMP9 and E-selectin compared to those of CT26 group. Inhibition of TNF-α elevation remarkably attenuated the increases of these liver inflammatory damage indicators and tumor-promoting factors.

Conclusion

These findings suggested that inhibition of TNF-α elevation delayed the IR-enhanced outgrowth of colorectal liver metastases by reducing IR-induced inflammatory damage and the formation of tumor-promoting microenvironments. Both Enbrel and low-dose TNF-α represented the potential therapeutic approaches for the protection of colorectal liver metastatic patients against IR injury-induced growth of liver micrometastases foci.

Neuroimmunomodulation in human autoimmune liver disease

Bidirectional interaction between immune and nervous systems is considered an important biological process in health and disease. However, little is known about the mechanisms involved in their interaction in the human liver. This study examines the distribution of intrahepatic NPY, SP immunoreactive (IR) nerve fibers and their antomical relationship with immunocells containing tumor necrosis factor-α (TNF-α) and nuclear factor κB (NF-κB) in patients with autoimmune hepatitis. Liver specimens were obtained from control liver and autoimmune hepatitis patients. The immunoreactivity was determined by immunohisto- and immunocytochemistry and confocal laser microscopy. In hepatitis, the number of NPY-IR and SP-IR nerve fibers increased significantly. These IR nerve fibers were in very close contact with the lymphocytes. In healthy controls, no NPY-IR, SP-IR or NF-κB IR lymphocytes and only a few TNF-α positive cells, were observed. In hepatitis, some of the lymphocytes showed immunoreactivity for SP and NPY in the portal area. Fluorescent double-labeled immunostaining revealed that in these cells NPY did not colocalize with TNF-α or NF-κB. However, some of the SP fluorescence-positive immune cells exhibited immunostaining for p65 of NF-κB, where their labeling was detected in the nuclei. Under the electronmicroscope, these cells could be identified (lymphocytes, plasmacells and mast cells). The gap between the IR nerve fibers and immunocells was 1 μm or even less. Overexpression of SP in lymphocytes may amplify local inflammation, while NPY may contribute to liver homeostasis in hepatitis. Neural immunomodulation (SP antagonists and NPY) might be a novel therapeutic concept in the management of liver inflammation.

Ineffective CD8(+) T-cell immunity to adeno-associated virus can result in prolonged liver injury and fibrogenesis

Chronic viral hepatitis depends on the inability of the T-cell immune response to eradicate antigen. This results in a sustained immune response accompanied by tissue injury and fibrogenesis. We have created a mouse model that reproduces these effects, based on the response of CD8(+) T cells to hepatocellular antigen delivered by an adeno-associated virus (AAV) vector. Ten thousand antigen-specific CD8(+) T cells undergo slow expansion in the liver and can precipitate a subacute inflammatory hepatitis with stellate cell activation and fibrosis. Over time, antigen-specific CD8(+) T cells show signs of exhaustion, including high expression of PD-1, and eventually both inflammation and fibrosis resolve. This model allows the investigation of both chronic liver immunopathology and its resolution.

Kupffer cells hasten resolution of liver immunopathology in mouse models of viral hepatitis

Kupffer cells (KCs) are widely considered important contributors to liver injury during viral hepatitis due to their pro-inflammatory activity. Herein we utilized hepatitis B virus (HBV)-replication competent transgenic mice and wild-type mice infected with a hepatotropic adenovirus to demonstrate that KCs do not directly induce hepatocellular injury nor do they affect the pathogenic potential of virus-specific CD8 T cells. Instead, KCs limit the severity of liver immunopathology. Mechanistically, our results are most compatible with the hypothesis that KCs contain liver immunopathology by removing apoptotic hepatocytes in a manner largely dependent on scavenger receptors. Apoptotic hepatocytes not readily removed by KCs become secondarily necrotic and release high-mobility group box 1 (HMGB-1) protein, promoting organ infiltration by inflammatory cells, particularly neutrophils. Overall, these results indicate that KCs resolve rather than worsen liver immunopathology.

Kupffer cells (KCs), the resident macrophages of the liver, are considered important contributors to liver injury during viral hepatitis due to their pro-inflammatory activity. Herein we utilized two different mouse models of viral hepatitis (where liver damage is triggered, as during viral hepatitis in humans, by virus-specific CD8 T cells) to show that KCs do not directly induce liver injury nor do they affect the pathogenic potential of virus-specific CD8 T cells. Instead, KCs limit the severity of liver immunopathology. Mechanistically, our results are most compatible with the hypothesis that KCs contain liver immunopathology by removing dying hepatocytes. Dying hepatocytes not readily removed by KCs release high-mobility group box 1 (HMGB-1) protein, promoting organ infiltration by inflammatory cells, particularly neutrophils. These results indicate that KCs resolve rather than worsen liver disease.

Antigen-presenting cell function in the tolerogenic liver environment

The demands that are imposed on the liver as a result of its function as a metabolic organ that extracts nutrients and clears gut-derived microbial products from the blood are met by a unique microanatomical and immunological environment. The inherent tolerogenicity of the liver and its role in the regulation of innate and adaptive immunity are mediated by parenchymal and non-parenchymal antigen-presenting cells (APCs), cell-autonomous molecular pathways and locally produced factors. Here, we review the central role of liver APCs in the regulation of hepatic immune function and also consider how recent insights may be applied in strategies to target liver tolerance for disease therapy.

LIGHT induces distinct signals to clear an AAV-expressed persistent antigen in the mouse liver and to induce liver inflammation

BACKGROUND

Infection with adeno-associated virus (AAV) vector with liver tropism leads to persistent expression of foreign antigens in the mouse liver, with no significant liver inflammation or pathology. This provides a model to investigate antigen persistence in the liver and strategies to modulate host immunity to reduce or clear the foreign antigen expressed from AAV vector in the liver.

METHODS/PRINCIPAL FINDINGS

We showed that expressing LIGHT with an adenovirus vector (Ad) in mice with established AAV in the liver led to clearance of the AAV. Ad-LIGHT enhanced CD8 effector T cells in the liver, correlated with liver inflammation. LTbetaR-Ig proteins blocked Ad-LIGHT in clearing AAV. Interestingly, in LTbetaR-null mice, Ad-LIGHT still cleared AAV but caused no significant liver inflammation.

CONCLUSIONS/SIGNIFICANCE

Our data suggest that LIGHT interaction with the LTbetaR plays a critical role in liver inflammation but is not required for LIGHT-mediated AAV clearance. These findings will shed light on developing novel immuno-therapeutics in treating people chronically infected with hepato-tropic viruses.