A20 (TNFAIP3) alleviates viral myocarditis through ADAR1/miR-1a-3p-dependent regulation

Objective To investigate the effect of A20 and how A20 is regulated in viral myocarditis (VMC). Methods BABL/C mice, primary neonatal rat cardiomyocytes and H9c2 cells were infected with Coxsackie virus B3 (CVB3) to establish animal and cellular models of VMC. H&E staining revealed the pathologic condition of myocardium. ELISA measured the serum levels of creatine kinase, creatine kinase isoenzyme and cardiac troponin I. The effects of A20, miR-1a-3p and ADAR1 were investigated using gain and loss of function approaches. ELISA measured the levels of IL-6, IL-18 and TNF-α in serum or cell culture supernatant. TUNEL staining and flow cytometry assessed the apoptosis of myocardium and cardiomyocytes, respectively. RNA-binding protein immunoprecipitation and dual-luciferase reporter assays verified the binding between A20 and miR-1a-3p. Co-immunoprecipitation assay verified the binding between ADAR1 and Dicer. Results A20 was underexpressed and miR-1a-3p was overexpressed in the myocardium of VMC mice as well as in CVB3-infected cardiomyocytes. Overexpression of A20 suppressed cardiomyocyte inflammation and apoptosis in vivo and in vitro. miR-1a-3p promoted CVB3-induced inflammation and apoptosis in cardiomyocytes by binding to A20. The expression of miR-1a-3p was regulated by ADAR1. ADAR1 promoted the slicing of miR-1a-3p precursor by binding to Dicer. Conclusion A20, regulated by ADAR1/miR-1a-3p, suppresses inflammation and cardiomyocyte apoptosis in VMC.

Establishing Cell Models to Understand Cellular Toxicity: Lessons Learned from an Unconventional Cell Type

The syndrome of uremic toxicity comprises a complex toxic milieu in-vivo, as numerous uremic substances accumulate and harm the organ systems. Among these substances, toxic and non-toxic players differently interfere with human cells. However, results from animal experiments are not always compatible with the expected reactions in human patients and studies on one organ system are limited in capturing the complexity of the uremic situation. In this narrative review, we present aspects relevant for cellular toxicity research based on our previous establishment of a human spermatozoa-based cell model, as follows: (i) applicability to compare the effects of more than 100 uremic substances, (ii) detection of the protective effects of uremic substances by the cellular responses towards the uremic milieu, (iii) inclusion of the drug milieu for cellular function, and (iv) transferability for clinical application, e.g., hemodialysis. Our technique allows the estimation of cell viability, vitality, and physiological state, not only restricted to acute or chronic kidney toxicity but also for other conditions, such as intoxications of unknown substances. The cellular models can clarify molecular mechanisms of action of toxins related to human physiology and therapy. Identification of uremic toxins retained during acute and chronic kidney injury enables further research on the removal or degradation of such products.

Fat Mass and Obesity–Associated Protein Promotes Liver Steatosis By Targeting PPARα

Background: Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. The fat mass and obesity–associated protein (FTO) has been shown to be involved in obesity; however, its role in NAFLD and the underlying molecular mechanisms remain largely unknown. Methods: FTO expression was first examined in the livers of patients with NAFLD and animal and cellular models of NAFLD using quantitative real-time polymerase chain reaction and western blotting. Next, its role in lipid accumulation in hepatocytes was assessed both in vitro and in vivo via gene overexpression and knockdown studies. Results: FTO expression was increased in the livers of mice and humans with hepatic steatosis, probably due to its decreased ubiquitination. FTO overexpression in HepG2 cells induced triglyceride accumulation, whereas FTO knockdown exerted an opposing effect. Consistent with the findings of in vitro studies, adeno-associated viruses 8 (AAV8)-mediated FTO overexpression in the liver promoted hepatic steatosis in C57BL/6J mice. Mechanistically, FTO inhibited the mRNA expression of peroxisome proliferator-activated receptor α (PPARα) in hepatocytes. Activation of PPARα by the PPARα agonist GW7647 reversed lipid accumulation in hepatocytes induced by FTO overexpression.Conclusions: Overall, FTO expression is increased in NAFLD, and it promotes hepatic steatosis by targeting PPARα.

A novel blood brain barrier-permeable IRE1 kinase inhibitor sensitizes glioblastoma to chemotherapy in mice.

Inositol Requiring Enzyme 1 (IRE1) is a bifunctional serine/threonine kinase and endoribonuclease. It is a major mediator of the Unfolded Protein Response (UPR), which is activated during endoplasmic reticulum (ER) stress. Tumor cells experience ER stress due to adverse microenvironmental cues such as hypoxia or nutrient shortage and high metabolic/protein folding demand. To cope with those stresses, cancer cells utilize IRE1 signaling as an adaptive mechanism. Here we report the discovery of novel IRE1 inhibitors identified through a structural exploration of the IRE1 kinase domain. We first characterized these candidates in vitro and in cellular models. We showed that all molecules inhibit IRE1 signaling and sensitize glioblastoma cells to the standard chemotherapeutic temozolomide (TMZ). From these inhibitors, we retained a Blood-Brain Barrier (BBB) permeable molecule (Z4P) and demonstrated its ability to inhibit Glioblastoma (GB) growth and to prevent relapse in vivo when administered together with TMZ. These results support the attractiveness of IRE1 as an adjuvant therapeutic target in GB. We thus satisfy an unmet need for targeted, non-toxic, IRE1 inhibitors as adjuvant therapeutic agents against GB.

Analysis of 5-Azacytidine Resistance Models Reveals a Set of Targetable Pathways

The mechanisms by which myelodysplastic syndrome (MDS) cells resist the effects of hypomethylating agents (HMA) are currently the subject of intensive research. A better understanding of mechanisms by which the MDS cell becomes to tolerate HMA and progresses to acute myeloid leukemia (AML) requires the development of new cellular models. From MDS/AML cell lines we developed a model of 5-azacytidine (AZA) resistance whose stability was validated by a transplantation approach into immunocompromised mice. When investigating mRNA expression and DNA variants of the AZA resistant phenotype we observed deregulation of several cancer-related pathways including the phosphatidylinosito-3 kinase signaling. We have further shown that these pathways can be modulated by specific inhibitors that, while blocking the proliferation of AZA resistant cells, are unable to increase their sensitivity to AZA. Our data reveal a set of molecular mechanisms that can be targeted to expand therapeutic options during progression on AZA therapy.

Extracellular Vesicle Delivery of Neferine for the Attenuation of Neurodegenerative Disease Proteins and Motor Deficit in an Alzheimer’s Disease Mouse Model

Exosomes are nano-extracellular vesicles with diameters ranging from 30 to 150 nm, which are secreted by the cell. With their role in drug cargo loading, exosomes have been applied to carry compounds across the blood–brain barrier in order to target the central nervous system (CNS). In this study, high-purity exosomes isolated by the ultra-high-speed separation method were applied as the natural compound carrier, with the loading efficiency confirmed by UHPLC-MS analysis. Through the optimization of various cargo loading methods using exosomes, this study compared the efficiency of different ways for the separation of exosomes and the exosome encapsulation of natural compounds with increasing molecular weights via extensive in vitro and in vivo efficacy studies. In a pharmacokinetic study, our data suggested that the efficiency of compound’s loading into exosomes is positively correlated to its molecular weight. However, with a molecular weight of greater than 1109 Da, the exosome-encapsulated natural compounds were not able to pass through the blood–brain barrier (BBB). In vitro cellular models confirmed that three of the selected exosome-encapsulated natural compounds—baicalin, hederagenin and neferine—could reduce the level of neurodegenerative disease mutant proteins—including huntingtin 74 (HTT74), P301L tau and A53T α-synuclein (A53T α-syn)—more effectively than the compounds alone. With the traditional pharmacological role of the herbal plant Nelumbo nucifera in mitigating anxiety, exosome-encapsulated-neferine was, for the first time, reported to improve the motor deficits of APP/PS1 (amyloid precursor protein/ presenilin1) double transgenic mice, and to reduce the level of β-amyloid (Aβ) in the brain when compared with the same concentration of neferine alone. With the current trend in advocating medicine–food homology and green healthcare, this study has provided a rationale from in vitro to in vivo for the encapsulation of natural compounds using exosomes for the targeting of BBB permeability and neurodegenerative diseases in the future.

Development and Optimization of A High-Throughput 3D Rat Purkinje Neuron Culture to Study Paraneoplastic Cerebellar Degeneration

Improved understanding of the mechanisms involved in neurodegenerative disease has been hampered by the lack of robust cellular models that faithfully replicate in vivo features. Here, we present a refined protocol for generating age-dependent, well-developed and synaptically active rat Purkinje neurons in a 3D cell network culture which are responsive to a disease inducer. Using our model, we found that the application of autoantibody Yo, a paraneoplastic cerebellar degeneration (PCD) inducer, alters the structure of the dendritic arbour of cultured Purkinje neurons. The numbers of dendrites per branch-order, the branch-order in itself and the dendritic length were reduced by anti-Yo, proving a functional role for anti-Yo in the pathogenesis of PCD. Our new ex-vivo model is flexible and can be used to investigate disease mechanisms that disturb Purkinje neuron function and communication in 3D. Since it is possible to use the approach in a multi-well format, this method also has high-throughput screening potential.

Radiolabeled Gold Nanoseeds Decorated with Substance P Peptides: Synthesis, Characterization and In Vitro Evaluation in Glioblastoma Cellular Models

Despite some progress, the overall survival of patients with glioblastoma (GBM) remains extremely poor. In this context, there is a pressing need to develop innovative therapy strategies for GBM, namely those based on nanomedicine approaches. Towards this goal, we have focused on nanoparticles (AuNP-SP and AuNP-SPTyr8) with a small gold core (ca. 4 nm), carrying DOTA chelators and substance P (SP) peptides. These new SP-containing AuNPs were characterized by a variety of analytical techniques, including TEM and DLS measurements and UV-vis and CD spectroscopy, which proved their high in vitro stability and poor tendency to interact with plasma proteins. Their labeling with diagnostic and therapeutic radionuclides was efficiently performed by DOTA complexation with the trivalent radiometals 67Ga and 177Lu or by electrophilic radioiodination with 125I of the tyrosyl residue in AuNP-SPTyr8. Cellular studies of the resulting radiolabeled AuNPs in NKR1-positive GBM cells (U87, T98G and U373) have shown that the presence of the SP peptides has a crucial and positive impact on their internalization by the tumor cells. Consistently, 177Lu-AuNP-SPTyr8 showed more pronounced radiobiological effects in U373 cells when compared with the non-targeted congener 177Lu-AuNP-TDOTA, as assessed by cell viability and clonogenic assays and corroborated by Monte Carlo microdosimetry simulations.

Role of Sulphur and Heavier Chalcogens on the Antioxidant Power and Bioactivity of Natural Phenolic Compounds

The activity of natural phenols is primarily associated to their antioxidant potential, but is ultimately expressed in a variety of biological effects. Molecular scaffold manipulation of this large variety of compounds is a currently pursued approach to boost or modulate their properties. Insertion of S/Se/Te containing substituents on phenols may increase/decrease their H-donor/acceptor ability by electronic and stereo-electronic effects related to the site of substitution and geometrical constrains. Oxygen to sulphur/selenium isosteric replacement in resveratrol or ferulic acid leads to an increase in the radical scavenging activity with respect to the parent phenol. Several chalcogen-substituted phenols inspired by Vitamin E and flavonoids have been prepared, which in some cases prove to be chain-breaking antioxidants, far better than the natural counterparts. Conjugation of catechols with biological thiols (cysteine, glutathione, dihydrolipoic acid) is easily achieved by addition to the corresponding ortho-quinones. Noticeable examples of compounds with potentiated antioxidant activities are the human metabolite 5-S-cysteinyldopa, with high iron-induced lipid peroxidation inhibitory activity, due to strong iron (III) binding, 5-S-glutathionylpiceatannol a most effective inhibitor of nitrosation processes, and 5-S-lipoylhydroxytyrosol, and its polysulfides that proved valuable oxidative-stress protective agents in various cellular models. Different methodologies have been used for evaluation of the antioxidant power of these compounds against the parent compounds. These include kinetics of inhibition of lipid peroxidation alkylperoxyl radicals, common chemical assays of radical scavenging, inhibition of the OH• mediated hydroxylation/oxidation of model systems, ferric- or copper-reducing power, scavenging of nitrosating species. In addition, computational methods allowed researchers to determine the Bond Dissociation Enthalpy values of the OH groups of chalcogen modified phenolics and predict the best performing derivative. Finally, the activity of Se and Te containing compounds as mimic of glutathione peroxidase has been evaluated, together with other biological activities including anticancer action and (neuro)protective effects in various cellular models. These and other achievements are discussed and rationalized to guide future development in the field.

YAP/TAZ in Bone and Cartilage Biology

YAP and TAZ were initially described as the main regulators of organ growth during development and more recently implicated in bone biology. YAP and TAZ are regulated by mechanical and cytoskeletal cues that lead to the control of cell fate in response to the cellular microenvironment. The mechanical component represents a major signal for bone tissue adaptation and remodelling, so YAP/TAZ contributes significantly in bone and cartilage homeostasis. Recently, mice and cellular models have been developed to investigate the precise roles of YAP/TAZ in bone and cartilage cells, and which appear to be crucial. This review provides an overview of YAP/TAZ regulation and function, notably providing new insights into the role of YAP/TAZ in bone biology.