Caspase 8 small interfering RNA prevents acute liver failure in mice

Apoptotic cell death in disease-Current understanding of the NCCD 2023

Apoptosis is a form of regulated cell death (RCD) that involves proteases of the caspase family. Pharmacological and genetic strategies that experimentally inhibit or delay apoptosis in mammalian systems have elucidated the key contribution of this process not only to (post-)embryonic development and adult tissue homeostasis, but also to the etiology of multiple human disorders. Consistent with this notion, while defects in the molecular machinery for apoptotic cell death impair organismal development and promote oncogenesis, the unwarranted activation of apoptosis promotes cell loss and tissue damage in the context of various neurological, cardiovascular, renal, hepatic, infectious, neoplastic and inflammatory conditions. Here, the Nomenclature Committee on Cell Death (NCCD) gathered to critically summarize an abundant pre-clinical literature mechanistically linking the core apoptotic apparatus to organismal homeostasis in the context of disease.

Pericyte-to-endothelial cell signaling via vitronectin-integrin regulates blood-CNS barrier

Endothelial cells of blood vessels of the central nervous system (CNS) constitute blood-CNS barriers. Barrier properties are not intrinsic to these cells; rather they are induced and maintained by CNS microenvironment. Notably, the abluminal surfaces of CNS capillaries are ensheathed by pericytes and astrocytes. However, extrinsic factors from these perivascular cells that regulate barrier integrity are largely unknown. Here, we establish vitronectin, an extracellular matrix protein secreted by CNS pericytes, as a regulator of blood-CNS barrier function via interactions with its integrin receptor, α5, in endothelial cells. Genetic ablation of vitronectin or mutating vitronectin to prevent integrin binding, as well as endothelial-specific deletion of integrin α5, causes barrier leakage in mice. Furthermore, vitronectin-integrin α5 signaling maintains barrier integrity by actively inhibiting transcytosis in endothelial cells. These results demonstrate that signaling from perivascular cells to endothelial cells via ligand-receptor interactions is a key mechanism to regulate barrier permeability.

Bioinformatics analysis reveals four major hexon variants of human adenovirus type-3 (HAdV-3) as the potential strains for development of vaccine and siRNA-based therapeutics against HAdV-3 respiratory infections

Human adenovirus type 3 (HAdV-3) encompasses 15-87% of all adenoviral respiratory infections. The significant morbidity and mortality, especially among the neonates and immunosuppressed patients, demand the need for a vaccine or a targeted antiviral against this type. However, due to the existence of multiple hexon variants (3Hv-1 to 3Hv-25), the selection of vaccine strains of HAdV-3 is challenging. This study was designed to evaluate HAdV-3 hexon variants for the selection of potential vaccine candidates and the use of hexon gene as a target for designing siRNA that can be used as a therapy. Based on the data of worldwide distribution, duration of circulation, co-circulation and their percentage among all the variants, 3Hv-1 to 3Hv-4 were categorized as the major hexon variants. Phylogenetic analysis and the percentage of homology in the hypervariable regions followed by multi-sequence alignment, zPicture analysis and restriction enzyme analysis were carried out. In the phylogram, the variants were arranged in different clusters. The HVR encoding regions of hexon of 3Hv-1 to 3Hv-4 showed 16 point mutations resulting in 12 amino acids substitutions. The homology in HVRs was 81.81-100%. Therefore, the major hexon variants are substantially different from each other which justifies their inclusion as the potential vaccine candidates. Interestingly, despite the significant differences in the DNA sequence, there were many conserved areas in the HVRs, and we have designed functional siRNAs form those locations. We have also designed immunogenic vaccine peptide epitopes from the hexon protein using bioinformatics prediction tool. We hope that our developed siRNAs and immunogenic vaccine peptide epitopes could be used in the future development of siRNA-based therapy and designing a vaccine against HAdV-3.

Evaluation of the therapeutic potential effect of Fas receptor gene knockdown in experimental model of non-alcoholic steatohepatitis

Aim: Stimulation of Fas death receptor is introduced as a major cause of non-alcoholic steatohepatitis (NASH) progression through suppression of cell viability. Therefore, the blocking of death pathways is hypothesised to be express new approaches to NASH therapy. For this purpose, current experiment applied synthetic small interference RNA (SiRNA) to trigger Fas death receptor and to show its potential therapeutic role in designed NASH model. Methods: Male mice were placed on a western diet (WD) for 8 weeks and exposed to cigarette smoke during the last 4 weeks of feeding to induce NASH model. In the next step, Fas SiRNA was injected to mice aiming to examine specific Fas gene silencing, after 8 weeks. As a control, mice received scrambled SiRNA. Reversible possibility of disease was examined by 3 weeks of recovery. Results: Analysis of data is accompanied with the significant histopathological changes (steatosis, ballooning and inflammation), increased lipid profile and hepatic enzyme activities (AST, ALT, ALP) plus TBARS as well as decreased antioxidants levels in NASH model. Upon Fas-SiRNA injection, almost all measured parameters of NASH such as overexpression of Fas receptor, caspase3, NF-kB genes and marked increase of hepatic TNF-α were significantly restored and were remained nearly unchanged following recovery liking as scrambled groups. Conclusions: The suppression of Fas receptor signalling subsequent RNAi therapy may represent an applicable strategy to decline hepatocyte damages and so NASH progression in mice.

Silencing of PHLPP1 promotes neuronal apoptosis and inhibits functional recovery after spinal cord injury in mice

AIM

Spinal cord injury (SCI) causes increased apoptosis of neurons, leading to irreversible dysfunction of the spinal cord. In this study, we investigated the effects of the progression of SCI and potential regulation of apoptosis after the Pleckstrin homology (PH) domain and leucine rich repeat protein phosphatase 1 (PHLPP1) gene was silenced.

MAIN METHODS

Spinal cord injection, and neuronal transfection with a recombinant adenovirus vector encoding small interfering RNA (siRNA) against PHLPP1 (AdsiPHLPP1) successfully silenced PHLPP1. These created in vivo and in vitro PHLPP1-silenced models, respectively, resulting in stable expression of the transgene in neurons.

KEY FINDINGS

The results showed that silencing of PHLPP1 evidently reduced levels of the nuclear factor erythroid 2-related factor 2 (Nrf2) after SCI. Western blot analysis revealed that the mice injected with AdsiPHLPP1 showed increased the expression of pro-apoptotic factors (Bax and cleaved-caspase 3), and reduced levels of neurotrophic (BDNF) and anti-apoptotic (Bcl-2) factors, both in vivo and in vitro. The motor function of AdsiPHLPP1-injected mice was restored more slowly than that of wild type (WT) mice. In addition, the number of motor neurons surviving in the anterior horn of the spinal cord was also reduced after SCI.

SIGNIFICANCE

Our results confirm that silencing of PHLPP1 promotes neuronal apoptosis and inhibits functional recovery after injury in vivo and in vitro. Consequently, PHLPP1 represents a potential therapeutic target gene for the clinical treatment of SCI.

Caspases in metabolic disease and their therapeutic potential

Caspases, a family of cysteine-dependent aspartate-specific proteases, are central to the maintenance of cellular and organismal homoeostasis by functioning as key mediators of the inflammatory response and/or apoptosis. Both metabolic inflammation and apoptosis play a central role in the pathogenesis of metabolic disease such as obesity and the progression of nonalcoholic steatohepatisis (NASH) to more severe liver disease. Obesity and nonalcoholic fatty liver disease (NAFLD) are the leading global health challenges associated with the development of numerous comorbidities including insulin resistance, type-2 diabetes and early mortality. Despite the high prevalence, current treatment strategies including lifestyle, dietary, pharmaceutical and surgical interventions, are often limited in their efficacy to manage or treat obesity, and there are currently no clinical therapies for NAFLD/NASH. As mediators of inflammation and cell death, caspases are attractive therapeutic targets for the treatment of these metabolic diseases. As such, pan-caspase inhibitors that act by blocking apoptosis have reached phase I/II clinical trials in severe liver disease. However, there is still a lack of knowledge of the specific and differential functions of individual caspases. In addition, cross-talk between alternate cell death pathways is a growing concern for long-term caspase inhibition. Evidence is emerging of the important cell-death-independent, non-apoptotic functions of caspases in metabolic homoeostasis that may be of therapeutic value. Here, we review the current evidence for roles of caspases in metabolic disease and discuss their potential targeting as a therapeutic strategy.

Translational Advances of Hydrofection by Hydrodynamic Injection

Hydrodynamic gene delivery has proven to be a safe and efficient procedure for gene transfer, able to mediate, in murine model, therapeutic levels of proteins encoded by the transfected gene. In different disease models and targeting distinct organs, it has been demonstrated to revert the pathologic symptoms and signs. The therapeutic potential of hydrofection led different groups to work on the clinical translation of the procedure. In order to prevent the hemodynamic side effects derived from the rapid injection of a large volume, the conditions had to be moderated to make them compatible with its use in mid-size animal models such as rat, hamster and rabbit and large animals as dog, pig and primates. Despite the different approaches performed to adapt the conditions of gene delivery, the results obtained in any of these mid-size and large animals have been poorer than those obtained in murine model. Among these different strategies to reduce the volume employed, the most effective one has been to exclude the vasculature of the target organ and inject the solution directly. This procedure has permitted, by catheterization and surgical procedures in large animals, achieving protein expression levels in tissue close to those achieved in gold standard models. These promising results and the possibility of employing these strategies to transfer gene constructs able to edit genes, such as CRISPR, have renewed the clinical interest of this procedure of gene transfer. In order to translate the hydrodynamic gene delivery to human use, it is demanding the standardization of the procedure conditions and the molecular parameters of evaluation in order to be able to compare the results and establish a homogeneous manner of expressing the data obtained, as ‘classic’ drugs.

Macrophage-targeting and reactive oxygen species (ROS)-responsive nanopolyplexes mediate anti-inflammatory siRNA delivery against acute liver failure (ALF)

Macrophage-targeting and ROS-degradable nanopolyplexes were developed to realize efficient TNF-α siRNA delivery toward the treatment of acute liver failure.

How successful has targeted RNA interference for hepatic fibrosis been?

INTRODUCTION

Exposure to toxins from the portal circulation, viral infection and by-products of metabolic activity make liver tissue prone to injury. When sustained, associated inflammation leads to activation of hepatic stellate cells (HSCs), deposition of extracellular matrix (ECM) proteins and complicating hepatic fibrosis.

AREAS COVERED

In this article, the authors discuss utility of therapeutic gene silencing to disable key steps of hepatic fibrogenesis. Strategies aimed at inhibiting HSC activation and silencing primary causes of fibrogenesis, such as viruses that cause chronic hepatitis, are reviewed. Both synthetic and expressed artificial intermediates of the RNAi pathway have potential to treat hepatic fibrosis, and each type of gene silencer has advantages for clinical translation. Silencing expression cassettes comprising DNA templates are compatible with efficient hepatotropic viral vectors, which may effect sustained gene silencing. By contrast, synthetic short interfering RNAs are amenable to chemical modification, incorporation into non-viral formulations, more precise dose control and large scale preparation.

EXPERT OPINION

Clinical translation of RNAi-based technology for treatment of hepatic fibrosis is now a realistic goal. However, achieving this aim will require safe, efficient delivery of artificial RNAi intermediates to target cells, economic large scale production of candidate drugs and specificity of action.

Targeting CCl4 -induced liver fibrosis by RNA interference-mediated inhibition of cyclin E1 in mice

Initiation and progression of liver fibrosis requires proliferation and activation of resting hepatic stellate cells (HSCs). Cyclin E1 (CcnE1) is the regulatory subunit of the cyclin-dependent kinase 2 (Cdk2) and controls cell cycle re-entry. We have recently shown that genetic inactivation of CcnE1 prevents activation, proliferation, and survival of HSCs and protects from liver fibrogenesis. The aim of the present study was to translate these findings into preclinical applications using an RNA interference (RNAi)-based approach. CcnE1-siRNA (small interfering RNA) efficiently inhibited CcnE1 gene expression in murine and human HSC cell lines and in primary HSCs, resulting in diminished proliferation and increased cell death. In C57BL/6 wild-type (WT) mice, delivery of stabilized siRNA using a liposome-based carrier targeted approximately 95% of HSCs, 70% of hepatocytes, and 40% of CD45⁺ cells after single injection. Acute CCl₄ -mediated liver injury in WT mice induced endogenous CcnE1 expression and proliferation of surviving hepatocytes and nonparenchymal cells, including CD45⁺ leukocytes. Pretreatment with CcnE1-siRNA reverted CcnE1 induction to baseline levels of healthy mice, which was associated with reduced liver injury, diminished proliferation of hepatocytes and leukocytes, and attenuated overall inflammatory response. For induction of liver fibrosis, WT mice were challenged with CCl₄ for 4-6 weeks. Co-treatment with CcnE1-siRNA once a week was sufficient to continuously block CcnE1 expression and cell-cycle activity of hepatocytes and nonparenchymal cells, resulting in significantly ameliorated liver fibrosis and inflammation. Importantly, CcnE1-siRNA also prevented progression of liver fibrosis if applied after onset of chronic liver injury.

CONCLUSION

Therapeutic targeting of CcnE1 in vivo using RNAi is feasible and has high antifibrotic activity. (Hepatology 2017;66:1242-1257).

Technical Improvement and Application of Hydrodynamic Gene Delivery in Study of Liver Diseases

Development of an safe and efficient in vivo gene delivery method is indispensable for molecular biology research and the progress in the following gene therapy. Over the past few years, hydrodynamic gene delivery (HGD) with naked DNA has drawn increasing interest in both research and potential clinic applications due to its high efficiency and low risk in triggering immune responses and carcinogenesis in comparison to viral vectors. This method, involving intravenous injection (i.v.) of massive DNA in a short duration, gives a transient but high in vivo gene expression especially in the liver of small animals. In addition to DNA, it has also been shown to deliver other substance such as RNA, proteins, synthetic small compounds and even viruses in vivo. Given its ability to robustly mimic in vivo hepatitis B virus (HBV) production in liver, HGD has become a fundamental and important technology on HBV studies in our group and many other groups. Recently, there have been interesting reports about the applications and further improvement of this technology in other liver research. Here, we review the principle, safety, current application and development of hydrodynamic delivery in liver disease studies, and discuss its future prospects, clinical potential and challenges.

Manipulation of Viral MicroRNAs as a Potential Antiviral Strategy for the Treatment of Cytomegalovirus Infection

Cytomegalovirus (CMV) infection leads to notable morbidity and mortality in immunosuppressed patients. Current antiviral drugs are effective but seriously limited in their long-term use due to their relatively high toxicity. In the present study, we characterized the expression of murine CMV microRNAs (MCMV miRNAs) both in vitro and in vivo. Although 29 miRNAs were detectable during in vitro infection, only 11 miRNAs (classified as Group 1) were detectable during in vivo infection, and as many as 18 viral miRNAs (classified as Group 2) were less detectable (<50% of animals) in both the liver and lungs. In addition, viral miRNA profiles in the blood revealed unstable and reduced expression. We next explored the in vitro effects of viral miRNAs on MCMV replication. The inhibition of Group 1 viral miRNAs had little effect on virus production, but transfected cells overexpressing miR-m01-3-5p, miR-M23-1-5p, miR-M55-1, and miR-m107-1-5p in Group 2 showed statistically lower viral loads than those transfected with control miRNA (29%, 29%, 39%, and 43%, respectively, versus control). Finally, we performed hydrodynamic injection of viral miRNA agomirs and observed lower levels of MCMV recurrence in the livers of animals overexpressing the miR-m01-3-5p or mcmv-miR-M23-1-5p agomirs compared with those of animals transfected with control agomir, confirming the antiviral effects of viral miRNA manipulation in vivo. Therefore, the manipulation of viral miRNA expression shows great therapeutic potential and represents a novel antiviral strategy for the miRNA-based treatment of cytomegalovirus infection.

Transforming growth factor β1 (TGFβ1)-induced CD44V6-NOX4 signaling in pathogenesis of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive clinical syndrome of fatal outcome. The lack of information about the signaling pathways that sustain fibrosis and the myofibroblast phenotype has prevented the development of targeted therapies for IPF. Our previous study showed that isolated fibrogenic lung fibroblasts have high endogenous levels of the hyaluronan receptor, CD44V6 (CD44 variant containing exon 6), which enhances the TGFβ1 autocrine signaling and induces fibroblasts to transdifferentiate into myofibroblasts. NADPH oxidase 4 (NOX4) enzyme, which catalyzes the reduction of O₂ to hydrogen peroxide (H₂O₂), has been implicated in the cardiac and lung myofibroblast phenotype. However, whether CD44V6 regulates NOX4 to mediate tissue repair and fibrogenesis is not well-defined. The present study assessed the mechanism of how TGF-β-1-induced CD44V6 regulates the NOX4/reactive oxygen species (ROS) signaling that mediates the myofibroblast differentiation. Specifically, we found that NOX4/ROS regulates hyaluronan synthesis and the transcription of CD44V6 via an effect upon AP-1 activity. Further, CD44V6 is part of a positive-feedback loop with TGFβ1/TGFβRI signaling that acts to increase NOX4/ROS production, which is required for myofibroblast differentiation, myofibroblast differentiation, myofibroblast extracellular matrix production, myofibroblast invasion, and myofibroblast contractility. Both NOX4 and CD44v6 are up-regulated in the lungs of mice subjected to experimental lung injury and in cases of human IPF. Genetic (CD44v6 shRNA) or a small molecule inhibitor (CD44v6 peptide) targeting of CD44v6 abrogates fibrogenesis in murine models of lung injury. These studies support a function for CD44V6 in lung fibrosis and offer proof of concept for therapeutic targeting of CD44V6 in lung fibrosis disorders.

The Influence of Extracellular RNA on Cell Behavior in Health, Disease and Regeneration

PURPOSE OF REVIEW

An overview of the role of extracellular RNAs (exRNA) in the regulation of homeostasis, disease progression, and regeneration is provided herein. Several exRNAs have been identified as potential biomarkers for disease and disease progression. In addition, the potential of exRNAs as a therapeutic modality is discussed.

RECENT FINDINGS

Fibrotic diseases of the lung, liver, and heart, among other organs share a number of identical exRNAs which play key roles in disease pathogenesis. Though regeneration is limited to only a few tissues in humans, small RNAs (e.g. microRNA) have been shown to be involved in the regenerative process of tissues such as liver and bone. The regulation of healing versus disease appears to be balanced by small RNAs. Because small RNAs are critical to health, they are being investigated as drug targets in multiple ongoing clinical trials. Preclinical studies suggest that promoting or blocking specific small RNAs can provide a novel therapeutic approach.

SUMMARY

exRNA can be utilized for both detection and treatment of disease. Natural and synthetic RNA carriers are being investigated as delivery methods for small RNA molecules. Current and future investigations are likely to lead to expanded applications for exRNAs.

Efficacy of hydrodynamic interleukin 10 gene transfer in human liver segments with interest in transplantation

Different diseases lead, during their advanced stages, to chronic or acute liver failure, whose unique treatment consists in organ transplantation. The success of intervention is limited by host immune response and graft rejection. The use of immunosuppressant drugs generally improve organ transplantation, but they cannot completely solve the problem. Also, their management is delicate, especially during the early stages of treatment. Thus, new tools to set an efficient modulation of immune response are required. The local expression of interleukin (IL) 10 protein in transplanted livers mediated by hydrodynamic gene transfer could improve the organ acceptance by the host because it presents the natural ability to modulate the immune response at different levels. In the organ transplantation scenario, IL10 has already demonstrated positive effects on graft tolerance. Hydrodynamic gene transfer has been proven to be safe and therapeutically efficient in animal models and could be easily moved to the clinic. In the present work, we evaluated efficacy of human IL10 gene transfer in human liver segments and the tissue natural barriers for gene entry into the cell, employing gold nanoparticles. In conclusion, the present work shows for the first time that hydrodynamic IL10 gene transfer to human liver segments ex vivo efficiently delivers a human gene into the cells. Indexes of tissue protein expression achieved could mediate local pharmacological effects with interest in controlling the immune response triggered after liver transplantation. On the other hand, the ultrastructural study suggests that the solubilized plasmid could access the hepatocyte in a passive manner mediated by the hydric flow and that an active mechanism of transportation could facilitate its entry into the nucleus. Liver Transplantation 23:50-62 2017 AASLD.

Questions and controversies: the role of necroptosis in liver disease

Acute and chronic liver injury results in hepatocyte death and turnover. If injury becomes chronic, the continuous cell death and turnover leads to chronic inflammation, fibrosis and ultimately cirrhosis and hepatocellular carcinoma. Controlling liver cell death both in acute injury, to rescue the liver from acute liver failure, and in chronic injury, to curb secondary inflammation and fibrosis, is of paramount importance as a therapeutic strategy. Both apoptosis and necrosis occur in the liver, but the occurrence of necroptosis in the liver and its contribution to liver disease is controversial. Necroptosis is a form of regulated necrosis which occurs in certain cell types when caspases (+/-cIAPs) are inhibited through the RIPK1-RIPK3 activation of MLKL. The occurrence of necroptosis in the liver has recently been examined in multiple liver injury models with conflicting results. The aim of this review is to summarize the published data with an emphasis on the controversies and remaining questions in the field.

Liver-targeted hydrodynamic gene therapy: Recent advances in the technique

One of the major research focuses in the field of gene therapy is the development of clinically applicable, safe, and effective gene-delivery methods. Since the first case of human gene therapy was performed in 1990, a number of gene-delivery methods have been developed, evaluated for efficacy and safety, and modified for human application. To date, viral-vector-mediated deliveries have shown effective therapeutic results. However, the risk of lethal immune response and carcinogenesis have been reported, and it is still controversial to be applied as a standard therapeutic option. On the other hand, delivery methods for nonviral vector systems have been developed, extensively studied, and utilized in in vivo gene-transfer studies. Compared to viral-vector mediated gene transfer, nonviral systems have less risk of biological reactions. However, the lower gene-transfer efficiency was a critical hurdle for applying them to human gene therapy. Among a number of nonviral vector systems, our studies focus on hydrodynamic gene delivery to utilize physical force to deliver naked DNA into the cells in the living animals. This method achieves a high gene-transfer level by DNA solution injections into the tail vein of rodents, especially in the liver. With the development of genome editing methods, in vivo gene-transfer therapy using this method is currently the focus in this research field. This review explains the method principle, efficiency, safety, and procedural modifications to achieve a high level of reproducibility in large-animal models.

Mouse genetic background contributes to hepatocyte susceptibility to Fas-mediated apoptosis

Liver disease progression is modulated by genetic modifiers in mouse strains and across human races and ethnicities. We hypothesized that hepatocyte culture duration and genetic background regulate hepatocyte susceptibility to apoptosis. Hepatocytes were isolated from FVB/N, C57BL/6, and C3H/He mice and cultured or treated with Fas ligand or acetaminophen after different culture times. Protein and mRNA expressions of Fas receptor, caspases-3/7/8, and Bak/Bax/Bid proteins were determined. FVB/N hepatocytes manifested rapid decreases of caspases-3/7 but not caspase-8 as culture time increased, which paralleled decreased susceptibility to apoptosis. Some changes were also found in Fas-receptor and Bak, Bax, and Bid proteins; caspase mRNA decreases were also noted. Caspase protein degradation was partially reversed by lysosomal protease but not proteasome or autophagy inhibitors. C57BL/6 and FVB/N hepatocytes behaved similarly in their limited susceptibility to apoptosis, whereas C3H/He hepatocytes show limited alterations in caspases, with consequent increased susceptibility to apoptosis. Similarly, C3H/He mice were more susceptible than C57BL/6 and FVB/N mice to Fas-mediated liver injury. Therefore there are significant mouse strain-dependent differences in susceptibility to apoptosis and selective loss of caspases upon short-term hepatocyte culture, with consequent decrease in susceptibility to apoptosis. These differences likely reflect genetic modifiers that provide resistance or predisposition to hepatocyte death.

Transarterial embolization combined with RNA interference targeting hypoxia-inducible factor-1α for hepatocellular carcinoma: a preliminary study of rat model

PURPOSE

To study whether transarterial embolization (TAE) with RNA interference (RNAi) targeting hypoxia-inducible factor-1α (HIF-1α) can improve efficacy of TAE in treating hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

CBRH-7919 rat hepatoma cell line was used and HCC models of rats were constructed. The siRNA transfection compound was made by mixing specific siRNA and Lipofectamine 2000™. Delivery and transfection of siRNA were administered by injecting iodized oil emulsion (diluted lipiodol and siRNA) via hepatic artery. The expression levels of mRNA and protein were detected using the real-time reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry and western blotting assays, respectively.

RESULTS

In vitro experiment, the specific HIF-1α-siRNA was proved to inhibit expression levels of HIF-1α and vascular endothelial growth factor (VEGF) effectively. In animal study, real-time RT-PCR assay showed the average relative mRNA expressions of HIF-1α were 0.31 ± 0.01, 0.65 ± 0.03, 0.46 ± 0.005, and 1.00 ± 0.00 in TAE + siRNA, siRNA, TAE, and control groups, respectively. Western blotting assay showed the average relative protein expressions of HIF-1α were 0.13 ± 0.02, 0.87 ± 0.02, 0.39 ± 0.02, and 1.02 ± 0.01 in TAE + siRNA, siRNA, TAE, and control groups, respectively. Compared with control, TAE, and siRNA groups, TAE + siRNA can significantly inhibit protein expressions of HIF-1α and VEGF (P _HIF-1α < 0.001; P _VEGF < 0.001). Overall survival of rats underwent TAE + siRNA was significantly longer than that of rats treated with TAE monotherapy (P = 0.001).

CONCLUSION

This animal study showed TAE combined with HIF-1α-RNAi could significantly improve efficacy of TAE in treating HCC by inhibiting expressions of HIF-1α and VEGF after TAE treatment.

Review of the Application of RNA Interference Technology in the Pharmaceutical Industry

Ribonucleic acid (RNA) interference (RNAi) is a recently discovered phenomenon whereby the introduction of double stranded (ds) RNA into the cytoplasm of the cell results in the specific and efficient degradation of complementary messenger (m) RNA and, therefore, reduced protein production. It was discovered by chance during attempts to develop flowers with increased colour intensity. The specific nature of the inhibition of protein production of cells has resulted in an explosion of research to understand and exploit RNAi. The technique is now established in in vitro systems, and much work is focussed in adapting RNAi for in vivo application. The potential of the technology in understanding physiological and pathological processes is significant, while its development as a therapeutic agent holds much promise as targeted agents. This review will describe the basic biological processes that drive RNAi, indicate current areas of areas research, and forecast future areas of development.

Protecting liver sinusoidal endothelial cells suppresses apoptosis in acute liver damage

AIM

Apoptosis is associated with various types of hepatic disorders. We have developed a novel cell-transfer drug delivery system (DDS) using a multifunctional envelope-type nano device that targets liver sinusoidal endothelial cells (LSECs). The purpose of this study was to determine the efficacy of the novel DDS containing siRNA at suppressing apoptosis in LSECs.

METHODS

Bax siRNA was transfected into a sinusoidal endothelial cell line (M1) to suppress apoptosis induced by an anti-Fas antibody and staurosporine. C57BL/6J mice were divided into three groups: (i) a control group, only intravenous saline; (ii) a nonselective group, injections of siRNA sealed in the nonselective DDS; and (iii) an LSEC-transfer efficient group, injections of siRNA sealed in an LSEC-transfer efficient DDS. Hepatic cell apoptosis was induced by an anti-Fas antibody.

RESULTS

Bax siRNA had an anti-apoptotic effect on M1 cells. Serum alanine aminotransferase was reduced in the LSEC-transfer efficient group, as were cleaved caspase-3 and the number of terminal deoxynucleotidyl transferase dUTP nick end labeling positive hepatocytes. Silver impregnation staining indicated that the sinusoidal space was maintained in the LSEC-transfer efficient group but not in the other groups. Electron microscopy showed that the LSECs were slightly impaired, although the sinusoidal structure was maintained in the LSEC-transfer efficient group.

CONCLUSION

Hepatocyte apoptosis was reduced by the efficient suppression of LSEC apoptosis with a novel DDS. Protecting the sinusoidal structure by suppressing LSEC damage will be an effective treatment for acute liver failure.

A MYC-aurora kinase A protein complex represents an actionable drug target in p53-altered liver cancer

MYC oncoproteins are involved in the genesis and maintenance of the majority of human tumors but are considered undruggable. By using a direct in vivo shRNA screen, we show that liver cancer cells that have mutations in the gene encoding the tumor suppressor protein p53 (Trp53 in mice and TP53 in humans) and that are driven by the oncoprotein NRAS become addicted to MYC stabilization via a mechanism mediated by aurora kinase A (AURKA). This MYC stabilization enables the tumor cells to overcome a latent G2/M cell cycle arrest that is mediated by AURKA and the tumor suppressor protein p19(ARF). MYC directly binds to AURKA, and inhibition of this protein-protein interaction by conformation-changing AURKA inhibitors results in subsequent MYC degradation and cell death. These conformation-changing AURKA inhibitors, with one of them currently being tested in early clinical trials, suppressed tumor growth and prolonged survival in mice bearing Trp53-deficient, NRAS-driven MYC-expressing hepatocellular carcinomas (HCCs). TP53-mutated human HCCs revealed increased AURKA expression and a positive correlation between AURKA and MYC expression. In xenograft models, mice bearing TP53-mutated or TP53-deleted human HCCs were hypersensitive to treatment with conformation-changing AURKA inhibitors, thus suggesting a therapeutic strategy for this subgroup of human HCCs.

Functional genetics-directed identification of novel pharmacological inhibitors of FAS- and TNF-dependent apoptosis that protect mice from acute liver failure

shRNA-mediated gene-silencing technology paired with cell-based functional readouts reveals potential targets directly, providing an opportunity to identify drugs against the target without knowing the precise role of the target in the pathophysiological processes of interest. By screening a lentiviral shRNA library targeting for major components of human signaling pathways and known drug targets, we identified and validated both canonical as well as 52 novel mediators of FAS and TNF ligand-induced apoptosis. Presence of potential therapeutic targets among these mediators was confirmed by demonstration of in vivo activity of siRNAs against four identified target candidates that protected mice from acute liver failure (ALF), a life-threatening disease with known involvement of death receptor (DR)-mediated apoptosis. Network-based modeling was used to predict small-molecule inhibitors for several candidate apoptosis mediators, including somatostatin receptor 5 (SSTR5) and a regulatory subunit of PP2A phosphatase, PPP2R5A. Remarkably, pharmacological inhibition of either SSTR5 or PPP2R5A reduced apoptosis induced by either FASL or TNF in cultured cells and dramatically improved survival in several mouse models of ALF. These results demonstrate the utility of loss-of-function genetic screens and network-based drug-repositioning methods for expedited identification of targeted drug candidates and revealed pharmacological agents potentially suitable for treatment of DR-mediated pathologies.

5-Aminolevulinic Acid-Mediated Sonodynamic Therapy Inhibits RIPK1/RIPK3-Dependent Necroptosis in THP-1-Derived Foam Cells

Necroptosis, or programmed necrosis, contributes to the formation of necrotic cores in atherosclerotic plaque in animal models. However, whether inhibition of necroptosis ameliorates atherosclerosis is largely unknown. In this study, we demonstrated that necroptosis occurred in clinical atherosclerotic samples, suggesting that it may also play an important role in human atherosclerosis. We established an in vitro necroptotic model in which necroptosis was induced in THP-1-derived foam cells by serum deprivation. With this model, we demonstrated that 5-aminolevulinic acid-mediated sonodynamic therapy (ALA-SDT) inhibited necroptosis while promoting apoptosis. ALA-SDT activated the caspase-3 and caspase-8 pathways in foam cells, which is responsible for the switch from necroptosis to apoptosis. The inhibition of either caspase-8 or caspase-3 abolished the anti-necroptotic effect of ALA-SDT. In addition, we found that caspase-3 activation peaked 4 hours after ALA-SDT treatment, 2 hours earlier than maximal caspase-8activation. Taken together, our data indicate that ALA-SDT mediates the switch from necroptosis to apoptosis by activating the caspase-3 and caspase-8 pathways and may improve the prognosis of atherosclerosis.

Image-Guided Hydrodynamic Gene Delivery: Current Status and Future Directions

Hydrodynamics-based delivery has been used as an experimental tool to express transgene in small animals. This in vivo gene transfer method is useful for functional analysis of genetic elements, therapeutic effect of oligonucleotides, and cancer cells to establish the metastatic cancer animal model for experimental research. Recent progress in the development of image-guided procedure for hydrodynamics-based gene delivery in large animals directly supports the clinical applicability of this technique. This review summarizes the current status and recent progress in the development of hydrodynamics-based gene delivery and discusses the future directions for its clinical application.

The protective effect of piperine on dextran sulfate sodium induced inflammatory bowel disease and its relation with pregnane X receptor activation

ETHNOPHARMACOLOGICAL RELEVANCE

Inflammatory bowel disease (IBD) is associated with chronic inflammation of the intestinal tract. Piperine (1-peperoylpiperidine), the primary lipophilic component in black pepper (Piper nigrum) and long pepper (Piper longum), has been reported to be effective for anti-inflammatory. Rencently, several ethnopharmacological purity compounds, such as baicalin and artemisinin, are reported to have potentially therapeutic role in treating IBD. In the present study, the effects of piperine on pregnane X receptor (PXR)-mediated CYP3A expression and its therapeutic role in IBD were investigated.

MATERIALS AND METHODS

LS174T cells and C57BL/6J mice were treated by the piperine. Gene expressions were analyzed by real-time PCR, Western blot analysis, transient transfections assay and histological analysis.

RESULTS

Data indicated that treatment of LS174T cells with piperine markedly increased both CYP3A4 and PXR mRNA and protein. Transient transfection experiments indicated that transcriptional activation of the CYP3A4 gene via piperine was PXR-dependent. Data show that pre-administration of piperine decreased clinical hallmarks of colitis in DSS-treated PXR mice as measured by body weight loss and assessment of diarrhea, rectal bleeding, colon length, and histology. Inflammatory mediators (CCR2, ICAM-1, IL-1β, IL-6, IL-10, iNOS, MCP-1, and TNFα) after DSS treatment were significantly decreased in mice pretreated with piperine but corresponding conditions did not occur in mice with down-regulation of PXR by small interfering RNA (siRNA).

CONCLUSION

Piperine is a potential agonist of PXR and an inducer of PXR, which may induce CYP3A4 gene expression at the mRNA and protein levels. These results establish that piperine may contribute to prevention or reduction of colonic inflammation.

1,8-Cineole Ameliorates Steatosis of Pten Liver Specific KO Mice via Akt Inactivation

Hepatocyte-specific Phosphatase and tensin homolog (Pten)-knockout (KO) mice exhibit hepatic lesions analogous to non-alcoholic steatohepatitis (NASH). 1,8-cineole is a monoterpene oxide and it has several biological effects including hepatoprotective effects. In this study we revealed that 1,8-cineole ameliorates NASH of Pten KO mice. Pten KO mice were assigned to a control group without any medication or to a 1,8-cineole group injected with 50 mg/kg i.p. twice per week for eight weeks. At eight weeks, livers from each group were processed to measure triglyceride (TG) content, gene expression analysis, western blot analysis, and histological examination including Oil red O staining. 1,8-cineole ameliorated hepatic steatosis in Pten KO mice, revealed by TG content and Oil red O staining. Moreover, 1,8-cineole downregulated collagen 1a1 expression and improved liver fibrosis. Thus, 1,8-cineole has potential as a candidate to treat NASH by inactivating the Akt/PI3-kinase pathway.

MiR-34a promotes Fas-mediated cartilage endplate chondrocyte apoptosis by targeting Bcl-2

Apoptosis of cartilage endplate (CEP) chondrocytes is associated with the pathogenesis of intervertebral disk degeneration (IDD). Recent studies have shown that miR-34a is crucially involved in chondrocyte apoptosis during osteoarthritic cartilage. Here, we investigated the involvement of miR-34a in CEP chondrocyte apoptosis in IDD. In human degenerated CEP chondrocytes, miRNA (miR)-34a was markedly elevated in association with increased apoptosis. Bioinformatics target prediction identified Bcl-2 as a putative target of miR-34a. Furthermore, miR-34a inhibited Bcl-2 expression by directly targeting their 3'-untranslated regions, and this inhibition was abolished by mutation of the miR-34a binding sites. In vitro, knockdown of miR-34a in human endplate chondrocytes resulted in overexpression of Bcl-2, whereas upregulation of miR-34a led to repression of Bcl-2. Fas-mediated apoptosis was decreased when antagonizing miR-34a with locked nucleotide analog-miR-34a in human endplate chondrocytes. Taken together, our results demonstrate that upregulated miR-34a potentiates Fas-mediated endplate chondrocyte apoptosis, which is associated with IDD.

The Power Decoder Simulator for the Evaluation of Pooled shRNA Screen Performance

RNA interference screening using pooled, short hairpin RNA (shRNA) is a powerful, high-throughput tool for determining the biological relevance of genes for a phenotype. Assessing an shRNA pooled screen’s performance is difficult in practice; one can estimate the performance only by using reproducibility as a proxy for power or by employing a large number of validated positive and negative controls. Here, we develop an open-source software tool, the Power Decoder simulator, for generating shRNA pooled screening experiments in silico that can be used to estimate a screen’s statistical power. Using the negative binomial distribution, it models both the relative abundance of multiple shRNAs within a single screening replicate and the biological noise between replicates for each individual shRNA. We demonstrate that this simulator can successfully model the data from an actual laboratory experiment. We then use it to evaluate the effects of biological replicates and sequencing counts on the performance of a pooled screen, without the necessity of gathering additional data. The Power Decoder simulator is written in R and Python and is available for download under the GNU General Public License v3.0.

TLR2 limits development of hepatocellular carcinoma by reducing IL18-mediated immunosuppression

Immune mechanisms underlying hepatocellular carcinoma (HCC) are not well understood. Here, we show that the Toll-like receptor TLR2 inhibits production of the proinflammatory cytokine IL18 and protects mice from DEN-induced liver carcinogenesis. On this protocol, Tlr2(-/-) mice exhibited more aggressive HCC development associated with impaired CD8(+) T-cell function. Furthermore, Ly6C(high)IL18Rα(+) myeloid-derived suppressor cells (MDSC) were increased in number in the livers of Tlr2(-/-) mice before tumor onset. MDSC in this setting exhibited higher iNOS levels that could inhibit IFNγ production and CD8(+) T-cell proliferation in vitro. Notably, Tlr2(-/-) hepatocytes produced more mature IL18 after DEN treatment that was sufficient to drive MDSC accumulation there. IL18 administration was sufficient to induce accumulation of MDSC, whereas hepatocyte-specific silencing of IL18 in Tlr2(-/-) mice decreased the proportion of MDSC, increased the proportion of functional CD8(+) T cells, and alleviated HCC progression. IL18 production was mediated by caspase-8 insofar as the decrease in its silencing was sufficient to attenuate levels of mature IL18 in Tlr2(-/-) mice. Furthermore, the TLR2 agonist Pam3CSK4 inhibited both caspase-8 and IL18 expression, decreasing MDSC, increasing CD8(+) T-cell function, and promoting HCC regression. Overall, our findings show how TLR2 deficiency accelerates IL18-mediated immunosuppression during liver carcinogenesis, providing new insights into immune control that may assist the design of effective immunotherapies to treat HCC.

Effects of Zhichan powder on signal transduction and apoptosis-associated gene expression in the substantia nigra of Parkinson's disease rats

Previous studies have shown that Zhichan powder elevated immunity and suppressed oxidation in mice. Rat models of Parkinson’s disease were induced by stereotaxically injecting 6-hydroxydopamine into the substantia nigra. The rat models were intragastrically treated with Zhichan powder, which is composed of milkvetch root, ginseng, bunge swallowwort root, himalayan teasel root, Magnolia officinalis, Ligustrum lucidum Ait. and szechwan lovage rhizome. Immunohistochemistry and reverse transcription-PCR results demonstrated that mRNA and protein expression of tumor necrosis factor receptor 1, Fas, caspase-8, cytochrome C, Bax, caspase-3, and p53 significantly increased, but Bcl-2 expression significantly decreased in the substantia nigra of rats with Parkinson’s disease. Following Zhichan powder administration, mRNA and protein expression of tumor necrosis factor receptor 1, Fas, caspase-8, cytochrome C, Bax, caspase-3, and p53 diminished, but Bcl-2 expression increased in the rat substantia nigra. These results indicate that Zhichan powder regulates signal transduction protein expression, inhibits apoptosis, and exerts therapeutic effects on Parkinson’s disease.

Hydrodynamic delivery

Hydrodynamic delivery (HD) is a broadly used procedure for DNA and RNA delivery in rodents, serving as a powerful tool for gene/protein drug discovery, gene function analysis, target validation, and identification of elements in regulating gene expression in vivo. HD involves a pressurized injection of a large volume of solution into a vasculature. New procedures are being developed to satisfy the need for a safe and efficient gene delivery in clinic. Here, we summarize the fundamentals of HD, its applications, and future perspectives for clinical use.

Therapeutic face of RNAi: in vivo challenges

INTRODUCTION

RNA interference is a sequence-specific gene silencing phenomenon in which small interfering RNAs (siRNAs) can trigger gene transcriptional and post-transcriptional silencing. This phenomenon represents an emerging therapeutic approach for in vivo studies by efficient delivery of specific synthetic siRNAs against diseases. Therefore, simultaneous development of synthetic siRNAs along with novel delivery techniques is considered as novel and interesting therapeutic challenges.

AREAS COVERED

This review provides a basic explanation to siRNA signaling pathways and their therapeutic challenges. Here, we provide a comprehensive explanation to failed and successful trials and their in vivo challenges.

EXPERT OPINION

Specific, efficient and targeted delivery of siRNAs is the major concern for their in vivo administrations. Also, anatomical barriers, drug stability and availability, immunoreactivity and existence of various delivery routes, different genetic backgrounds are major clinical challenges. However, successful administration of siRNA-based drugs is expected during foreseeable features. But, their systemic applications will depend on strong targeted drug delivery strategies.

The microbiota regulates susceptibility to Fas-mediated acute hepatic injury

Whereas a significant role for intestinal microbiota in affecting the pathogenesis and progression of chronic hepatic diseases is well documented, the contribution of the intestinal flora to acute liver injury has not been extensively addressed. Elucidating the influence of the intestinal microbiota on acute liver inflammation would be important for better understanding the transition from acute injury to chronic liver disease. Using the Concanavalin A (ConA)-induced liver injury model in laboratory mice, we show that the severity of acute hepatic damage varies greatly among genetically identical mice raised in different environments and harboring distinct microbiota. Through reconstitution of germ-free (GF) mice, and the co-housing of conventional mice, we provide direct evidence that manipulation of the intestinal flora alters susceptibility to ConA-induced liver injury. Through deep sequencing of the fecal microbiome, we observe that the relative abundance of Ruminococcaceae, a Gram(+) family within the class Clostridia, but distinct from segmented filamentous bacteria, is positively associated with the degree of liver damage. Searching for the underlying mechanism(s) that regulate susceptibility to ConA, we provide evidence that the extent of liver injury following triggering of the death receptor Fas varies greatly as a function of the microbiota. We demonstrate that the extent of Fas-induced liver injury increases in GF mice after microbiota reconstitution, and decreases in conventionally raised mice following reduction in intestinal bacterial load, by antibiotic treatment. We also show that the regulation of sensitivity to Fas-induced liver injury is dependent upon the toll-like receptor signaling molecule MyD88. In conclusion, the status and composition of the intestinal microbiota determine the susceptibility to ConA-induced acute liver injury. The microbiota acts as a rheostat, actively modulating the extent of liver damage in response to Fas triggering.

Lipid nanoparticles as carriers for RNAi against viral infections: current status and future perspectives

The efforts made to develop RNAi-based therapies have led to productive research in the field of infections in humans, such as hepatitis C virus (HCV), hepatitis B virus (HBV), human immunodeficiency virus (HIV), human cytomegalovirus (HCMV), herpetic keratitis, human papillomavirus, or influenza virus. Naked RNAi molecules are rapidly digested by nucleases in the serum, and due to their negative surface charge, entry into the cell cytoplasm is also hampered, which makes necessary the use of delivery systems to exploit the full potential of RNAi therapeutics. Lipid nanoparticles (LNP) represent one of the most widely used delivery systems for in vivo application of RNAi due to their relative safety and simplicity of production, joint with the enhanced payload and protection of encapsulated RNAs. Moreover, LNP may be functionalized to reach target cells, and they may be used to combine RNAi molecules with conventional drug substances to reduce resistance or improve efficiency. This review features the current application of LNP in RNAi mediated therapy against viral infections and aims to explore possible future lines of action in this field.

Construction and application of a novel hepatocyte-directed vector to simultaneous knockdown and overexpression of multiple genes

BACKGROUND & AIMS

Liver disease, such as malignancy and hepatitis, often correlates with several genetic disorders. We aimed to construct a hepatocyte-specific vector that could manipulate multiple genes simultaneously.

METHODS

We selected a highly efficient hepatocyte-specific α-foetoprotein (AFP) enhancer/albumin promoter (an RNA polymerase II promoter) to express our gene of interest and transcribe microRNA-based shRNAs (shRNAmir). Multiple shRNAmirs were assembled together in tandem to enhance the gene-silencing effect. By employing the AFP enhancer/albumin promoter and inserting an internal ribosome entry site (IRES), a hepatocyte-specific, multi-reporter vector that overexpressed both β-galactosidase (LacZ) and DsRed2 while simultaneously knocking down both EGFP and luciferase expression was successfully constructed and functionally tested in vitro.

RESULTS

The reporter genes in the multireporter vector were easily replaced by immune-related genes to construct the Multi-Vector, which overexpressed human interleukin 10 and silenced both CCL5 and CX3CL1 (FKN) simultaneously in vivo; visualization of DsRed2 coexpressed to monitor vector function in vivo confirmed that the Multi-Vector was successfully introduced into the host. Simultaneous manipulation of these multiple genes by the Multi-Vector synergistically inhibited acute liver injury induced by Poly I:C/D-GalN injection in mice. The multifunctional cassette was also packaged in and successfully delivered by an adenoviral vector.

CONCLUSIONS

We successfully engineered a vector that can simultaneously regulate multiple genes from a single multigene-containing vector in a hepatocyte-specific manner, suggesting the possibility that this method could be extensively and practically utilized in liver gene therapy.

Bcl-2 down-regulation by small interfering RNA induces Beclin1-dependent autophagy in human SGC-7901 cells

While Bcl-2 protein is involved in the regulation of apoptosis, recent research showed that Beclin1, described as the essential autophagy effector and haploinsufficient tumor suppressor, was originally isolated as a Bcl-2 interacting protein. Beclin1 interacts with Bcl-2 through a BH3 domain; nevertheless, the function of the anti-apoptotic gene, Bcl-2, in autophagy is not well understood. We explored the role of Bcl-2 in autophagy in human SGC-7901 cells in which Bcl-2 is overexpressed. Knockdown of Bcl-2 by small interfering RNA in human SGC-7901 cells downregulated Bcl-2 protein levels ∼82% and induced autophagy. Beclin1 protein, the first identified autophagy gene product, was induced by as much as 58%. Transmission electron microscopy and DNA fragmentation assay showed that autophagy was enhanced, but not apoptosis, in Bcl-2 siRNA treated cells. The results provide evidence that knockout the anti-apoptotic gene Bcl-2 induces autophagy in SGC-7901 cells and Bcl-2 specific siRNA may be used as a potential therapeutic strategy in gastric cancer cells that overexpress Bcl-2.

In vivo siRNA delivery of Keap1 modulates death and survival signaling pathways and attenuates concanavalin-A-induced acute liver injury in mice

Oxidative stress contributes to the progression of acute liver failure (ALF). Transcription factor nuclear factor-erythroid 2-related factor (Nrf2) serves as an endogenous regulator by which cells combat oxidative stress. We have investigated liver damage and the balance between death and survival signaling pathways in concanavalin A (ConA)-mediated ALF using in vivo siRNA delivery targeting Keap1 in hepatocytes. For that goal, mice were injected with Keap1- or luciferase-siRNA-containing liposomes via the tail vein. After 48 hours, ALF was induced by ConA. Liver histology, pro-inflammatory mediators, antioxidant responses, cellular death, and stress and survival signaling were assessed. Keap1 mRNA and protein levels significantly decreased in livers of Keap1-siRNA-injected mice. In these animals, histological liver damage was less evident than in control mice when challenged with ConA. Likewise, markers of cellular death (FasL and caspases 8, 3 and 1) decreased at 4 and 8 hours post-injection. Nuclear Nrf2 and its target, hemoxygenase 1 (HO1), were elevated in Keap1-siRNA-injected mice compared with control animals, resulting in reduced oxidative stress in the liver. Similarly, mRNA levels of pro-inflammatory cytokines were reduced in livers from Keap1-siRNA-injected mice. At the molecular level, activation of c-jun (NH2) terminal kinase (JNK) was ameliorated, whereas the insulin-like growth factor I receptor (IGFIR) survival pathway was maintained upon ConA injection in Keap1-siRNA-treated mice. In conclusion, our results have revealed a potential therapeutic use of in vivo siRNA technology targeted to Keap1 to combat oxidative stress by modulating Nrf2-mediated antioxidant responses and IGFIR survival signaling during the progression of ALF.

Src-homology 2 domain-containing tyrosine phosphatase 2 promotes oral cancer invasion and metastasis

Background

Tumor invasion and metastasis represent a major unsolved problem in cancer pathogenesis. Recent studies have indicated the involvement of Src-homology 2 domain-containing tyrosine phosphatase 2 (SHP2) in multiple malignancies; however, the role of SHP2 in oral cancer progression has yet to be elucidated. We propose that SHP2 is involved in the progression of oral cancer toward metastasis.

Methods

SHP2 expression was evaluated in paired oral cancer tissues by using immunohistochemical staining and real-time reverse transcription polymerase chain reaction. Isogenic highly invasive oral cancer cell lines from their respective low invasive parental lines were established using a Boyden chamber assay, and changes in the hallmarks of the epithelial-mesenchymal transition (EMT) were assessed to evaluate SHP2 function. SHP2 activity in oral cancer cells was reduced using si-RNA knockdown or enforced expression of a catalytically deficient mutant to analyze migratory and invasive ability in vitro and metastasis toward the lung in mice in vivo.

Results

We observed the significant upregulation of SHP2 in oral cancer tissues and cell lines. Following SHP2 knockdown, the oral cancer cells markedly attenuated migratory and invasion ability. We observed similar results in phosphatase-dead SHP2 C459S mutant expressing cells. Enhanced invasiveness was associated with significant upregulation of E-cadherin, vimentin, Snail/Twist1, and matrix metalloproteinase-2 in the highly invasive clones. In addition, we determined that SHP2 activity is required for the downregulation of phosphorylated ERK1/2, which modulates the downstream effectors, Snail and Twist1 at a transcript level. In lung tissue sections of mice, we observed that HSC3 tumors with SHP2 deletion exhibited significantly reduced metastatic capacity, compared with tumors administered control si-RNA.

Conclusions

Our data suggest that SHP2 promotes the invasion and metastasis of oral cancer cells. These results provide a rationale for further investigating the effects of small-molecule SHP2 inhibitors on the progression of oral cancer, and indicate a previously unrecognized SHP2-ERK1/2-Snail/Twist1 pathway that is likely to play a crucial role in oral cancer invasion and metastasis.

Silence of NLRP3 suppresses atherosclerosis and stabilizes plaques in apolipoprotein E-deficient mice

OBJECTIVES

The role of the NLRP3 inflammasome in atherosclerosis remains controversial. The aim of this study was to determine whether inhibition of NLRP3 signaling by lentivirus-mediated RNA interference could reduce atherosclerosis and stabilizes plaques. We also tried to explore the mechanisms of the impact of NLRP3 inflammasome on atherosclerosis.

METHODS

Apolipoprotein E-deficient mice aged 8 weeks were fed a high-fat diet and were injected with NLRP3 interfering or mock viral suspension after 4 weeks. Lentivirus transfer was repeated in 2 weeks. Four weeks after the first lentivirus injection, we evaluated the effects of NLRP3 gene silencing on plaque composition and stability and on cholesterol efflux and collagen metabolism, by histopathologic analyses and real-time PCR.

RESULTS

Gene silence of NLRP3 prevented plaques progression and inhibited inductions of proinflammatory cytokines. Moreover, this RNA interference reduced plaque content of macrophages and lipid, and increased plaque content of smooth muscle cells and collagen, leading to the stabilizing of atherosclerotic plaques.

CONCLUSIONS

NLRP3 inflammasomes may play a vital role in atherosclerosis, and lentivirus-mediated NLRP3 silencing would be a new strategy to inhibit plaques progression and to reduce local inflammation.

α-1-antitrypsin inhibits acute liver failure in mice

Acute liver failure remains a critical clinical condition, with high mortality rates, and increased apoptosis of hepatocytes represents a key event in the cause of liver failure. Alpha-1-antitrypsin (AAT) is synthesized and secreted mainly by hepatocytes, and plasma purified AAT is used for augmentation therapy in patients with AAT deficiency. Because AAT therapy exerts antiinflammatory and immune modulatory activities in various experimental models, and it was recently suggested that AAT exerts antiapoptotic activities, we aimed to explore whether administration of AAT may represent a therapeutic strategy to treat acute liver failure in mice. Well-established preclinical models of acute liver failure such as the Jo2 FAS/CD95 activating model and models of acetaminophen and α-amanitin poisoning were used. Therapeutic effects of AAT were evaluated by monitoring animal survival, histopathological changes, measurement of caspase activity, and serum cytokine levels. Systemic treatment with AAT significantly decreased Jo2-induced liver cell apoptosis and prolonged survival of mice. Native and oxidized (lacking elastase inhibitory activity) forms of AAT were equally effective in preventing acute liver injury and showed direct inhibition of active caspase-3 and -8 in liver homogenates and in a cell-free system in vitro. Concomitantly, mice treated with AAT showed significantly lower serum levels of tumor necrosis factor alpha (TNF-α), which also paralleled the reduced activity of ADAM17 (TACE). Noticeably, the increased survival and a reduction of apoptotic hepatocytes were also observed in the α-amanitin and acetaminophen-induced liver injury mouse models.

CONCLUSION

Our data suggest that systemic administration of AAT can be a promising therapy to treat acute liver failure and clinical studies to explore this treatment in humans should be initiated.

Overexpression of Atg5 in mice activates autophagy and extends lifespan

Autophagy has been implicated in the ageing process, but whether autophagy activation extends lifespan in mammals is unknown. Here we show that ubiquitous overexpression of Atg5, a protein essential for autophagosome formation, extends median lifespan of mice by 17.2%. We demonstrate that moderate overexpression of Atg5 in mice enhances autophagy, and that Atg5 transgenic mice showed anti-ageing phenotypes, including leanness, increased insulin sensitivity and improved motor function. Furthermore, mouse embryonic fibroblasts cultured from Atg5 transgenic mice are more tolerant to oxidative damage and cell death induced by oxidative stress, and this tolerance was reversible by treatment with an autophagy inhibitor. Our observations suggest that the leanness and lifespan extension in Atg5 transgenic mice may be the result of increased autophagic activity.

Changes in autophagy have been shown to modulate lifespan in lower organisms. Here, Pyo et al. show that mice globally overexpressing the autophagy protein Atg5 live longer and are leaner than normal mice, providing the first evidence that increased autophagy extends lifespan in mammals.

Hepatitis B virus infection and immunopathogenesis in a humanized mouse model: induction of human-specific liver fibrosis and M2-like macrophages

The mechanisms of chronic HBV infection and immunopathogenesis are poorly understood due to a lack of a robust small animal model. Here we report the development of a humanized mouse model with both human immune system and human liver cells by reconstituting the immunodeficient A2/NSG (NOD.Cg-Prkdc(scid) Il2rg(tm1Wjl)/SzJ mice with human HLA-A2 transgene) with human hematopoietic stem cells and liver progenitor cells (A2/NSG-hu HSC/Hep mice). The A2/NSG-hu HSC/Hep mouse supported HBV infection and approximately 75% of HBV infected mice established persistent infection for at least 4 months. We detected human immune responses, albeit impaired in the liver, chronic liver inflammation and liver fibrosis in infected animals. An HBV neutralizing antibody efficiently inhibited HBV infection and associated liver diseases in humanized mice. In addition, we found that the HBV mediated liver disease was associated with high level of infiltrated human macrophages with M2-like activation phenotype. Importantly, similar M2-like macrophage accumulation was confirmed in chronic hepatitis B patients with liver diseases. Furthermore, gene expression analysis showed that induction of M2-like macrophage in the liver is associated with accelerated liver fibrosis and necrosis in patients with acute HBV-induced liver failure. Lastly, we demonstrate that HBV promotes M2-like activation in both M1 and M2 macrophages in cell culture studies. Our study demonstrates that the A2/NSG-hu HSC/Hep mouse model is valuable in studying HBV infection, human immune responses and associated liver diseases. Furthermore, results from this study suggest a critical role for macrophage polarization in hepatitis B virus-induced immune impairment and liver pathology.

Mechanisms of Acute Liver Failure

Acute liver failure (ALF) is characterized by the sudden onset of liver failure in a patient without evidence of chronic liver disease. This definition is important, as it differentiates patients with ALF from patients who suffer from liver failure owing to end-stage chronic liver disease [1].

Apoptosis and necrosis in the liver

Because of its unique function and anatomical location, the liver is exposed to a multitude of toxins and xenobiotics, including medications and alcohol, as well as to infection by hepatotropic viruses, and therefore, is highly susceptible to tissue injury. Cell death in the liver occurs mainly by apoptosis or necrosis, with apoptosis also being the physiologic route to eliminate damaged or infected cells and to maintain tissue homeostasis. Liver cells, especially hepatocytes and cholangiocytes, are particularly susceptible to death receptor-mediated apoptosis, given the ubiquitous expression of the death receptors in the organ. In a quite unique way, death receptor-induced apoptosis in these cells is mediated by both mitochondrial and lysosomal permeabilization. Signaling between the endoplasmic reticulum and the mitochondria promotes hepatocyte apoptosis in response to excessive free fatty acid generation during the metabolic syndrome. These cell death pathways are partially regulated by microRNAs. Necrosis in the liver is generally associated with acute injury (i.e., ischemia/reperfusion injury) and has been long considered an unregulated process. Recently, a new form of "programmed" necrosis (named necroptosis) has been described: the role of necroptosis in the liver has yet to be explored. However, the minimal expression of a key player in this process in the liver suggests this form of cell death may be uncommon in liver diseases. Because apoptosis is a key feature of so many diseases of the liver, therapeutic modulation of liver cell death holds promise. An updated overview of these concepts is given in this article.

Melatonin treatment reduces endoplasmic reticulum stress and modulates the unfolded protein response in rabbits with lethal fulminant hepatitis of viral origin

Hepatocyte apoptosis plays an important role in the development of fulminant hepatic failure (FHF). The objective of this study was to investigate whether endoplasmic reticulum (ER) stress and unfolded protein response (UPR) inhibition is an underlying mechanism of melatonin anti-apoptotic effects in an animal model of FHF of viral origin induced by the rabbit hemorrhagic disease virus (RHDV). Rabbits were experimentally infected with 2 × 10(4) hemagglutination units of a RHDV isolate and received melatonin at two concentrations of 10 mg/kg and 20 mg/kg at 0 hr, 12 hr and 24 hr postinfection. RHDV infection induced increased expression of CCAAT/enhancer-binding protein homologous protein (CHOP), immunoglobulin heavy chain binding protein (BiP/GRP78), glucose-regulated protein 94 (GRP94), phospho-c-Jun N-terminal kinase (JNK) and caspase-12. These effects were attenuated by melatonin. Double immunofluorescence staining showed colocalization of CHOP and cleaved caspase-3 in liver sections of RHDV-infected rabbits, while immunostaining decreased markedly with melatonin treatment. RHDV infection resulted in significant increases in the mRNA levels of activating transcription factor 6 (ATF6), ATF4, inositol-requiring enzyme 1 (IRE1), spliced X-box binding protein-1 (XBP1s) and tumor necrosis factor receptor-associated factor 2 (TRAF2). Melatonin attenuated the extent of the changes. Data obtained provide evidence that in rabbits with experimental infection by RHDV, reduction in apoptotic liver damage by melatonin is associated with attenuation of ER stress through a modulation of the three arms of UPR signaling and further support a potential hepatoprotective role of melatonin in FHF.

New Transfection Agents Based on Liposomes Containing Biosurfactant MEL-A

Nano vectors are useful tools to deliver foreign DNAs, oligonucleotides, and small interfering double-stranded RNAs (siRNAs) into mammalian cells with gene transfection and gene regulation. In such experiments we have found the liposomes with a biosurfacant mannosylerythriol lipid (MEL-A) are useful because of their high transfer efficiency, and their unique mechanism to transfer genes to target cells with the lowest toxicity. In the present review we will describe our current work, which may contribute to the great advance of gene transfer to target cells and gene regulations. For more than two decades, the liposome technologies have changed dramatically and various methods have been proposed in the fields of biochemistry, cell biology, biotechnology, and so on. In addition, they were towards to pharmaceutics and clinical applications. The liposome technologies were expected to use gene therapy, however, they have not reached a requested goal as of yet. In the present paper we would like to present an approach using a biosurfactant, MEL-A, which is a surface-active compound produced by microorganisms growing on water-insoluble substrates and increases efficiency in gene transfection. The present work shows new transfection agents based on liposomes containing biosurfactant MEL-A.

Hepatocyte caspase-8 is an essential modulator of steatohepatitis in rodents

In human and murine models of nonalcoholic steatohepatitis (NASH), increased hepatocyte apoptosis is a critical mechanism contributing to inflammation and fibrogenesis. Caspase 8 (Casp8) is essential for death-receptor-mediated apoptosis activity and therefore its modulation might be critical for the pathogenesis of NASH. The aim was to dissect the role of hepatocyte Casp8 in a murine model of steatohepatitis. We generated hepatocyte-specific Casp8 knockout (Casp8(Δhep) ) mice. Animals were fed with a methionine-choline-deficient (MCD) diet. Liver injury was assessed by histopathological analysis, apoptotic death, serum alanine aminotransferase (ALT), fluorescent-activated cell sorter (FACS), analysis of liver infiltration and inflammation, reactive oxygen species (ROS), and liver fibrosis. MCD feeding triggered steatosis, hepatic lipid storage, and accumulation of free fatty acid (FFA) in wildtype (WT) livers, which were significantly reduced in Casp8(Δhep) animals. Additionally, lack of Casp8 expression in hepatocytes reduced the MCD-dependent increase in apoptosis and decreased expression of proinflammatory cytokines as well as hepatic infiltration. As a consequence, ROS production was lower, leading to a reduction in the progression of liver fibrosis in Casp8(Δhep) livers.

CONCLUSION

Selective ablation of Casp8 in hepatocytes ameliorates development of NASH by modulating liver injury. Casp8-directed therapy might be a plausible treatment for patients with steatohepatitis. (HEPATOLOGY 2013;57:2189-2201).

Characterization of neuronal cell death in the spiral ganglia of a mouse model of endolymphatic hydrops

HYPOTHESIS

Spiral ganglion neurons (SGN) in the Phex male mouse, a murine model of postnatal endolymphatic hydrops (ELH) undergo progressive deterioration reminiscent of human and other animal models of ELH with features suggesting apoptosis as an important mechanism.

BACKGROUND

Histologic analysis of the mutant's cochlea demonstrates ELH by postnatal Day (P) 21 and SGN loss by P90. The SGN loss seems to occur in a consistent topographic pattern beginning at the cochlear apex.

METHODS

SGN were counted at P60, P90, and P120. Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), quantitative PCR, and immunohistochemical analyses of activated caspase-3, caspase-8, and caspase-9 were performed on cochlear sections obtained from mutants and controls. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling assay (TUNEL) was carried out on 2 mutants and 2 controls.

RESULTS

Corrected SGN counts in control mice were greater in the apical turn of the cochleae at P90 and P120, respectively (p < 0.01). Increased expression of activated caspase-3, caspase-8, and caspase-9 was seen in the mutant. At later time points, activated caspase expression gradually declined in the apical turns and increased in basal turns of the cochlea. Quantitative and semiquantitative PCR analysis confirmed increased expression of caspase-3, caspase-8, and caspase-9 at P21 and P40. TUNEL staining demonstrated apoptosis at P90 in the apical and basal turns of the mutant cochleae.

CONCLUSION

SGN degeneration in the Phex /Y mouse seems to mimic patterns observed in other animals with ELH. Apoptosis plays an important role in the degeneration of the SGN in the Phex male mouse.