Receptor-specific TRAIL as a means to achieve targeted elimination of activated hepatic stellate cells

Circulating cytokines and alcoholic liver disease: a two-sample bidirectional Mendelian randomization study

BACKGROUND

Increased inflammation in the liver during ethanol exposure is a major feature of alcoholic liver disease (ALD). An important contributing component to the development of ALD is the inflammatory response brought on by immunological response, however the connection between individual circulating cytokines and ALD is still unclear. To ascertain the causation, we conducted a two-sample bidirectional Mendelian randomization research.

METHODS

We extracted 41 cytokines and growth factors of 8293 Europeans and ALD cases of the same ethnicity (1416 cases and 217,376 controls) from the Genome-Wide Association Studies (GWAS) database for two-sample bidirectional MR analysis.

RESULTS

Our analyses suggest that higher interleukin-7 (IL-7) levels are associated with an increased risk of ALD (p = 0.028, OR = 1.191,95% CI = 1.019-1.392), while tumor necrosis factor related apoptosis inducing ligand (TRAIL) is a protective factor for ALD (p = 0.032, OR = 0.863, 95% CI = 0.754-0.988) which can reduce the risk of disease occurrence. In addition, genetically predicted ALD does not affect the expression of circulating cytokines regulators.

CONCLUSIONS

Our study supports that cytokines play a pivotal role in the pathogenesis of ALD. To determine the mechanisms and pathways of action of these biomarkers, further basic research is required to ensure their clinical suitability for preventing and treating ALD.

Fibronectin-targeted FUD and PEGylated FUD peptides for fibrotic diseases

Tissue fibrosis is characterized by excessive deposition of extracellular matrix (ECM) molecules. Fibronectin (FN) is a glycoprotein found in the blood and tissues, a key player in the assembly of ECM through interaction with cellular and extracellular components. Functional Upstream Domain (FUD), a peptide derived from an adhesin protein of bacteria, has a high binding affinity for the N-terminal 70-kDa domain of FN that plays a crucial role in FN polymerization. In this regard, FUD peptide has been characterized as a potent inhibitor of FN matrix assembly, reducing excessive ECM accumulation. Furthermore, PEGylated FUD was developed to prevent rapid elimination of FUD and enhance its systemic exposure in vivo. Herein, we summarize the development of FUD peptide as a potential anti-fibrotic agent and its application in experimental fibrotic diseases. In addition, we discuss how modification of the FUD peptide via PEGylation impacts pharmacokinetic profiles of the FUD peptide and can potentially contribute to anti-fibrosis therapy.

Liver fibrosis therapy based on biomimetic nanoparticles which deplete activated hepatic stellate cells

Liver fibrosis is one of the most common liver diseases with substantial morbidity and mortality. However, effective therapy for liver fibrosis is still lacking. Considering the key fibrogenic role of activated hepatic stellate cells (aHSCs), here we reported a strategy to deplete aHSCs by inducing apoptosis as well as quiescence. Therefore, we engineered biomimetic all-trans retinoic acid (ATRA) loaded PLGA nanoparticles (NPs). HSC (LX2 cells) membranes, presenting the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), were coated on the surface of the nanoparticles, while the clinically approved agent ATRA with anti-fibrosis ability was encapsulated in the inner core. The biomimetic coating of TRAIL-expressing HSC membranes does not only provide homologous targeting to HSCs, but also effectively triggers apoptosis of aHSCs. ATRA could induce quiescence of activated fibroblasts. While TM-NPs (i.e. membrane coated NPs without ATRA) and ATRA/NPs (i.e. non-coated NPs loaded with ATRA) only showed the ability to induce apoptosis and decrease the α-SMA expression in aHSCs, respectively, TM-ATRA/NPs induced both apoptosis and quiescence in aHSCs, ultimately leading to improved fibrosis amelioration in both carbon tetrachloride-induced and methionine and choline deficient L-amino acid diet induced liver fibrosis mouse models. We conclude that biomimetic TM-ATRA/NPs may provide a novel strategy for effective antifibrosis therapy.

Moringa oleifera Prevents In vivo Carbon Tetrachloride-Induced Liver Fibrosis through Targeting Hepatic Stellate Cells

BACKGROUND: Moringa oleifera (MO) exhibits hepatoprotective properties and provides an anti-liver fibrosis effect. However, its mechanism related to the anti-liver fibrosis effect was still unclear. AIM: The objective of this study was to explain the mechanism of liver fibrosis prevention by MO through hepatic stellate cells (HSCs). MATERIALS AND METHODS: The liver fibrosis model was induced by the intraperitoneal injection of 10% CCl4 twice a week at a one cc/kg BW dose for 12 weeks and followed by a quantity of 2 cc/kg BW for the past 2 weeks. Ethanol extract of MO leaves (150, 300, and 600 mg/kg) was orally administered daily. Double immunofluorescence staining and terminal deoxynucleotidyl transferase dUTP nick end labeling analysis were applied to analyze the markers involved in HSCs activation and a-HSC apoptosis. RESULTS: The results showed that the administration of MO could reduce transforming growth factor-β and nuclear factor-kappa B (NFκB), increase the expression of tumor necrosis factor-related apoptosis-inducing ligand-receptor 2 and caspase-3, and increase the number of apoptosis a-HSCs. CONCLUSION: This study showed that the ethanol extract of MO leaves could inhibit liver fibrosis by inhibiting HSCs activation and inducing of a-HSCs apoptosis through the extrinsic pathway.

Receptor Specificity Engineering of TNF Superfamily Ligands

The tumor necrosis factor (TNF) ligand family has nine ligands that show promiscuity in binding multiple receptors. As different receptors transduce into diverse pathways, the study on the functional role of natural ligands is very complex. In this review, we discuss the TNF ligands engineering for receptor specificity and summarize the performance of the ligand variants in vivo and in vitro. Those variants have an increased binding affinity to specific receptors to enhance the cell signal conduction and have reduced side effects due to a lowered binding to untargeted receptors. Refining receptor specificity is a promising research strategy for improving the application of multi-receptor ligands. Further, the settled variants also provide experimental guidance for engineering receptor specificity on other proteins with multiple receptors.

Stellate Cells in the Tumor Microenvironment

As tumor microenvironments share many of the same qualities as chronic wounds, attention is turning to the wound-repair cells that support the growth of cancerous cells. Stellate cells are star-shaped cells that were first discovered in the perisinusoidal spaces in the liver and have been found to support wound healing by the secretion of growth factors and extracellular matrix. They have since been also found to serve a similar function in the pancreas. In both organs, the wound-healing process may become dysregulated and lead to pathological fibrosis (also known as cirrhosis in the liver). In recent years there has been increasing attention paid to the role of these cells in tumor formation and progression. They may be a factor in initiating the first steps of carcinogenesis such as with liver cirrhosis and hepatocellular carcinoma and also contribute to continued tumor growth, invasion, metastasis, evasion of the immune system, and resistance to chemotherapy, in cancers of both the liver and pancreas. In this chapter we aim to review the structure and function of hepatic and pancreatic stellate cells and their contributions to the tumor microenvironment in their respective cancers and also discuss potential new targets for cancer therapy based on our new understanding of these vital components of the tumor stroma.

CRISPR-mediated ablation of overexpressed EGFR in combination with sunitinib significantly suppresses renal cell carcinoma proliferation

Receptor tyrosine kinases, such as VEGFR, PDGFR and EGFR, play important roles in renal cancer. In this study, we investigated EGFR knockout as a therapeutic approach in renal cell carcinoma (RCC). We showed that a renal cell carcinoma cell line (RC21) has higher expression of EGFR as compared to other frequently used cell lines such as HEK293, A549, Hela and DLD1. Ablation of EGFR by CRISPR/Cas9 significantly restrained tumor cell growth and activated the MAPK (pERK1/2) pathway. The VEGFR and PDGFR inhibitor, sunitinib, attenuated the expression of MAPK (pERK1/2) and pAKT induced by EGFR loss and further inhibited EGFR-/- cell proliferation. We showed that loss of EGFR eventually leads to resistance to SAHA and cisplatin. Furthermore, EGFR loss induced G2/M phase arrest and resulted in an increased resistance to TNF-related apoptosis-inducing ligand (TRAIL) in renal cell carcinoma. Thus, ablation of overexpressed EGFR by CRISPR/Cas9 alone or in combination with sunitinib may be a new treatment option for renal cell carcinoma.

Liver Fibrosis: Mechanistic Concepts and Therapeutic Perspectives

Liver fibrosis due to viral or metabolic chronic liver diseases is a major challenge of global health. Correlating with liver disease progression, fibrosis is a key factor for liver disease outcome and risk of hepatocellular carcinoma (HCC). Despite different mechanism of primary liver injury and disease-specific cell responses, the progression of fibrotic liver disease follows shared patterns across the main liver disease etiologies. Scientific discoveries within the last decade have transformed the understanding of the mechanisms of liver fibrosis. Removal or elimination of the causative agent such as control or cure of viral infection has shown that liver fibrosis is reversible. However, reversal often occurs too slowly or too infrequent to avoid life-threatening complications particularly in advanced fibrosis. Thus, there is a huge unmet medical need for anti-fibrotic therapies to prevent liver disease progression and HCC development. However, while many anti-fibrotic candidate agents have shown robust effects in experimental animal models, their anti-fibrotic effects in clinical trials have been limited or absent. Thus, no approved therapy exists for liver fibrosis. In this review we summarize cellular drivers and molecular mechanisms of fibrogenesis in chronic liver diseases and discuss their impact for the development of urgently needed anti-fibrotic therapies.

NanoTRAIL-Oncology: A Strategic Approach in Cancer Research and Therapy

TRAIL is a member of the tumor necrosis factor superfamily that can largely trigger apoptosis in a wide variety of cancer cells, but not in normal cells. However, insufficient exposure to cancer tissues or cells and drug resistance has severely impeded the clinical application of TRAIL. Recently, nanobiotechnology has brought about a revolution in advanced drug delivery for enhanced anticancer therapy using TRAIL. With the help of materials science, immunology, genetic engineering, and protein engineering, substantial progress is made by expressing fusion proteins with TRAIL, engineering TRAIL on biological membranes, and loading TRAIL into functional nanocarriers or conjugating it onto their surfaces. Thus, the nanoparticle-based TRAIL (nanoTRAIL) opens up intriguing opportunities for efficient and safe bioapplications. In this review, the mechanisms of action and biological function of TRAIL, as well as the current status of TRAIL treatment, are comprehensively discussed. The application of functional nanotechnology combined with TRAIL in cancer therapy is also discussed.

TRAIL-Dependent Resolution of Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is the most common form of interstitial lung disease characterized by the persistence of activated myofibroblasts resulting in excessive deposition of extracellular matrix proteins and profound tissue remodeling. In the present study, the expression of tumor necrosis factor- (TNF-) related apoptosis-inducing ligand (TRAIL) was key to the resolution of bleomycin-induced pulmonary fibrosis. Both in vivo and in vitro studies demonstrated that Gr-1⁺TRAIL⁺ bone marrow-derived myeloid cells blocked the activation of lung myofibroblasts. Although soluble TRAIL was increased in plasma from IPF patients, the presence of TRAIL⁺ myeloid cells was markedly reduced in IPF lung biopsies, and primary lung fibroblasts from this patient group expressed little of the TRAIL receptor-2 (DR5) when compared with appropriate normal samples. IL-13 was a potent inhibitor of DR5 expression in normal fibroblasts. Together, these results identified TRAIL⁺ myeloid cells as a critical mechanism in the resolution of pulmonary fibrosis, and strategies directed at promoting its function might have therapeutic potential in IPF.

Hepatic stellate cell-targeted therapy for hepatic fibrosis

Hepatic fibrosis is the ultimate pathological feature of all forms of chronic hepatic damage. There is currently no clinical cure for advanced liver fibrosis. Activation and proliferation of hepatic stellate cells (HSCs) is a key step in the development of liver fibrosis, and therefore, HSCs are target cells for hepatic fibrosis treatment. Targeted delivery of drugs to activated HSCs would increase the drug concentration in the liver at the sites of active fibrogenesis and avoid undesirable systemic effects. Mannose 6-phosphate modified human serum albumin, vitamin A, and hyaluronic acid are three kinds of the most investigated carriers that deliver drugs to the activated HSCs specifically. Conjugation of these carriers with molecules with anti-fibrosis activity such as angiotensin receptor blockers, activin-like kinase 5 inhibitors, Rho-kinase inhibitors, small interfering RNAs, hepatocyte growth factor gene, or nitrogen monoxide can lead to specific distribution and effects in HSCs. This review will focus on these preclinical developments of HSCs-targeted drug conjugates for the treatment of liver fibrosis.

TRAIL regulatory receptors constrain human hepatic stellate cell apoptosis

The TRAIL pathway can mediate apoptosis of hepatic stellate cells to promote the resolution of liver fibrosis. However, TRAIL has the capacity to bind to regulatory receptors in addition to death-inducing receptors; their differential roles in liver fibrosis have not been investigated. Here we have dissected the contribution of regulatory TRAIL receptors to apoptosis resistance in primary human hepatic stellate cells (hHSC). hHSC isolated from healthy margins of liver resections from different donors expressed variable levels of TRAIL-R2/3/4 (but negligible TRAIL-R1) ex vivo and after activation. The apoptotic potential of TRAIL-R2 on hHSC was confirmed by lentiviral-mediated knockdown. A functional inhibitory role for TRAIL-R3/4 was revealed by shRNA knockdown and mAb blockade, showing that these regulatory receptors limit apoptosis of hHSC in response to both oligomerised TRAIL and NK cells. A close inverse ex vivo correlation between hHSC TRAIL-R4 expression and susceptibility to apoptosis underscored its central regulatory role. Our data provide the first demonstration of non-redundant functional roles for the regulatory TRAIL receptors (TRAIL-R3/4) in a physiological setting. The potential for these inhibitory TRAIL receptors to protect hHSC from apoptosis opens new avenues for prognostic and therapeutic approaches to the management of liver fibrosis.