Transcriptomics of natural and synthetic vitamin D in human hepatocyte lipotoxicity.

Vitamin D (VD) has been used to prevent nonalcoholic fatty liver disease (NAFLD), a condition of lipotoxicity associated with a defective metabolism and function of this vitamin. Different forms of VD are available and can be used for this scope, but their effects on liver cell lipotoxicity remain unexplored. In this study we compared a natural formulation rich in VD2 (Shiitake Mushroom extract or SM-VD2) with a synthetic formulation containing pure VD3 (SV-VD3) and the bioactive metabolite 1,25(OH)2-D3. These were investigated in chemoprevention mode in human HepaRG liver cells supplemented with oleic and palmitic acid to induce lipotoxicity. All the different forms of VD showed similar efficacy in reducing the levels of lipotoxicity and the changes that lipotoxicity induced on the cellular transcriptome. However, the three forms of VD generated different gene fingerprints suggesting diverse, even if functionally convergent, cytoprotective mechanisms. Main differences were (1) the number of differentially expressed genes (SV-VD3 > 1,25[OH]2-D3 > SM-VD2), (2) their identity that demonstrated significant gene homology between SM-VD2 and 1,25(OH)2-D3, and (3) the number and type of biological functions identified by ingenuity pathway analysis as relevant to liver metabolism and cytoprotection annotations. Immunoblot confirmed a different response of VDR and other VDR-related proteins to natural and synthetic VD formulations, including FXR, PXR, PPARγ/PGC-1α, and CYP3A4 and CYP24A1. In conclusion, different responses of the cellular transcriptome drive the cytoprotective effect of natural and synthetic formulations of VD in the free fatty acid-induced lipotoxicity of human hepatocytes.

Wheat germ oil vitamin E cytoprotective effect and its nutrigenomics signature in human hepatocyte lipotoxicity.

Wheat germ oil (WGO) is rich in α-tocopherol (vitamin E, VE), a vitamin that has long been suggested to exert hepatoprotective effects. In this study, this function of WGO-VE and its transcriptomics fingerprint were investigated in comparison with RRR-α-tocopherol and all-rac-α-tocopherol (nVE and sVE, respectively), in human liver cells treated with oleic acid (OA) to develop steatosis and lipotoxicity. Used in chemoprevention mode, all the VE formulations afforded significant reduction of the OA-induced steatosis and its consequent impact on lipotoxicity indicators, including ROS production and efflux (as H2O2), and apoptotic and necrotic cell death. A trend toward a better control of lipotoxicity was observed for WGO-VE and nVE compared to sVE. Gene microarray data demonstrated that these effects of VE formulations were associated with significantly different responses of the cellular transcriptome to compensate for the modifications of OA treatment, including the downregulation of cellular homeostasis genes and the induction of genes associated with defects of liver cell metabolism, fibrosis and inflammation, liver disease and cancer. Ingenuity Pathway Analysis data showed that WGO-VE modulated genes associated with liver carcinogenesis and steatosis, whereas nVE modulated genes involved in liver cell metabolism and viability biofunctions; sVE did not significantly modulate any gene dataset relevant to such biofunctions. In conclusion, WGO-VE prevents lipotoxicity in human liver cells modulating genes that differ from those affected by the natural or synthetic forms of pure VE. These differences can be captured by precision nutrition tools, reflecting the molecular complexity of this VE-rich extract and its potential in preventing specific cues of hepatocellular lipotoxicity.

Intra-Articular Route for the System of Molecules 14G1862 from Centella Asiatica: Pain Relieving and Protective Effects in a Rat Model of Osteoarthritis.

Current pharmacological therapies for the management of chronic articular diseases are far from being satisfactory, so new strategies need to be investigated. We tested the intra-articular pain relieving properties of a system of molecules from a characterized Centella asiatica extract (14G1862) in a rat model of osteoarthritis induced by monoiodoacetate (MIA). 14G1862 (0.2-2 mg mL-1) was intra-articularly (i.a.) injected 7 days after MIA, behavioural and histological evaluations were performed 14, 30 and 60 days after treatments. Moreover, the effect of 14G1862 on nitrate production and iNOS expression in RAW 264.7 macrophages stimulated with LPS was assessed. In vitro, 14G1862 treatment attenuated LPS-induced NO production and iNOS expression in a comparable manner to celecoxib. In vivo, 14G1862 significantly reduced mechanical allodynia and hyperalgesia, spontaneous pain and motor alterations starting on day 14 up to day 60. The efficacy was higher or comparable to that evoked by triamcinolone acetonide (100 µg i.a.) used as reference drug. Histological evaluation highlighted the improvement of several morphological parameters in MIA + 14G1862-treated animals with particularly benefic effects on joint space and fibrin deposition. In conclusion, i.a. treatment with Centella asiatica is a candidate to be a novel effective approach for osteoarthritis therapy.

Hyperthermic treatment at 56 °C induces tumour-specific immune protection in a mouse model of prostate cancer in both prophylactic and therapeutic immunization regimens.

Most active cancer immunotherapies able to induce a long-lasting protection against tumours are based on the activation of tumour-specific cytotoxic T lymphocytes (CTLs). Cell death by hyperthermia induces apoptosis followed by secondary necrosis, with the production of factors named "danger associated molecular pattern" (DAMP) molecules (DAMPs), that activate dendritic cells (DCs) to perform antigen uptake, processing and presentation, followed by CTLs cross priming. In many published studies, hyperthermia treatment of tumour cells is performed at 42-45 °C; these temperatures mainly promote cell surface expression of DAMPs. Treatment at 56 °C of tumour cells was shown to induce DAMPs secretion rather than their cell surface expression, improving DC activation and CTL cross priming in vitro. Thus we tested the relevance of this finding in vivo on the generation of a tumour-specific memory immune response, in the TRAMP-C2 mouse prostate carcinoma transplantable model. TRAMP-C2 tumour cells treated at 56 °C were able not only to activate DCs in vitro but also to trigger a tumour-specific CTL-dependent immune response in vivo. Prophylactic vaccination with 56 °C-treated TRAMP-C2 tumour cells alone provided protection against TRAMP-C2 tumour growth in vivo, whilst in the therapeutic regimen, control of tumour growth was achieved combining immunization with adjuvant chemotherapy.

Tailored chemokine receptor modification improves homing of adoptive therapy T cells in a spontaneous tumor model.

In recent years, tumor Adoptive Cell Therapy (ACT), using administration of ex vivo-enhanced T cells from the cancer patient, has become a promising therapeutic strategy. However, efficient homing of the anti-tumoral T cells to the tumor or metastatic site still remains a substantial hurdle. Yet the tumor site itself attracts both tumor-promoting and anti-tumoral immune cell populations through the secretion of chemokines. We attempted to identify these chemokines in a model of spontaneous metastasis, in order to "hijack" their function by expressing matching chemokine receptors on the cytotoxic T cells used in ACT, thus allowing us to enhance the recruitment of these therapeutic cells. Here we show that this enabled the modified T cells to preferentially home into spontaneous lymph node metastases in the TRAMP model, as well as in an inducible tumor model, E.G7-OVA. Due to the improved homing, the modified CD8+ T cells displayed an enhanced in vivo protective effect, as seen by a significant delay in E.G7-OVA tumor growth. These results offer a proof of principle for the tailored application of chemokine receptor modification as a means of improving T cell homing to the target tumor, thus enhancing ACT efficacy. Surprisingly, we also uncover that the formation of the peri-tumoral fibrotic capsule, which has been shown to impede T cell access to tumor, is partially dependent on host T cell presence. This finding, which would be impossible to observe in immunodeficient model studies, highlights possible conflicting roles that T cells may play in a therapeutic context.

Lack of TNF-alpha receptor type 2 protects motor neurons in a cellular model of amyotrophic lateral sclerosis and in mutant SOD1 mice but does not affect disease progression.

Changes in the homeostasis of tumor necrosis factor α (TNFα) have been demonstrated in patients and experimental models of amyotrophic lateral sclerosis (ALS). However, the contribution of TNFα to the development of ALS is still debated. TNFα is expressed by glia and neurons and acts through the membrane receptors TNFR1 and TNFR2, which may have opposite effects in neurodegeneration. We investigated the role of TNFα and its receptors in the selective motor neuron death in ALS in vitro and in vivo. TNFR2 expressed by astrocytes and neurons, but not TNFR1, was implicated in motor neuron loss in primary SOD1-G93A co-cultures. Deleting TNFR2 from SOD1-G93A mice, there was partial but significant protection of spinal motor neurons, sciatic nerves, and tibialis muscles. However, no improvement of motor impairment or survival was observed. Since the sciatic nerves of SOD1-G93A/TNFR2-/- mice showed high phospho-TAR DNA-binding protein 43 (TDP-43) accumulation and low levels of acetyl-tubulin, two indices of axonal dysfunction, the lack of symptom improvement in these mice might be due to impaired function of rescued motor neurons. These results indicate the interaction between TNFR2 and membrane-bound TNFα as an innovative pathway involved in motor neuron death. Nevertheless, its inhibition is not sufficient to stop disease progression in ALS mice, underlining the complexity of this pathology. We show evidence of the involvement of neuronal and astroglial TNFR2 in the motor neuron degeneration in ALS. Both concur to cause motor neuron death in primary astrocyte/spinal neuron co-cultures. TNFR2 deletion partially protects motor neurons and sciatic nerves in SOD1-G93A mice but does not improve their symptoms and survival. However, TNFR2 could be a new target for multi-intervention therapies.

Obestatin regulates adipocyte function and protects against diet-induced insulin resistance and inflammation.

The metabolic actions of the ghrelin gene-derived peptide obestatin are still unclear. We investigated obestatin effects in vitro, on adipocyte function, and in vivo, on insulin resistance and inflammation in mice fed a high-fat diet (HFD). Obestatin effects on apoptosis, differentiation, lipolysis, and glucose uptake were determined in vitro in mouse 3T3-L1 and in human subcutaneous (hSC) and omental (hOM) adipocytes. In vivo, the influence of obestatin on glucose metabolism was assessed in mice fed an HFD for 8 wk. 3T3-L1, hSC, and hOM preadipocytes and adipocytes secreted obestatin and showed specific binding for the hormone. Obestatin prevented apoptosis in 3T3-L1 preadipocytes by increasing phosphoinositide 3-kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK)1/2 signaling. In both mice and human adipocytes, obestatin inhibited isoproterenol-induced lipolysis, promoted AMP-activated protein kinase phosphorylation, induced adiponectin, and reduced leptin secretion. Obestatin also enhanced glucose uptake in either the absence or presence of insulin, promoted GLUT4 translocation, and increased Akt phosphorylation and sirtuin 1 (SIRT1) protein expression. Inhibition of SIRT1 by small interfering RNA reduced obestatin-induced glucose uptake. In HFD-fed mice, obestatin reduced insulin resistance, increased insulin secretion from pancreatic islets, and reduced adipocyte apoptosis and inflammation in metabolic tissues. These results provide evidence of a novel role for obestatin in adipocyte function and glucose metabolism and suggest potential therapeutic perspectives in insulin resistance and metabolic dysfunctions.

Fluoride-containing bioactive glasses inhibit pentose phosphate oxidative pathway and glucose 6-phosphate dehydrogenase activity in human osteoblasts.

Bioactive glasses such as Hench's 45S5 (Bioglass) have applications to tissue engineering as well as bone repair, and the insertion of fluoride in their composition has been proposed to enhance their bioactivity. In view of a potential clinical application, we investigated whether fluoride-containing glasses exert toxic effects on human MG-63 osteoblasts, and whether and how fluoride, which is released in the cell culture medium, might play a role in such cytotoxicity. A 24h incubation with 50 microg/ml (12.5 microg/cm(2)) of fluoride-containing bioactive glasses termed HCaCaF(2) (F content: 5, 10 and 15 mol.%) caused the release of lactate dehydrogenase in the extracellular medium (index of cytotoxicity), the accumulation of intracellular malonyldialdehyde (index of lipoperoxidation), and the increase of glutathione consumption. Furthermore, fluoride-containing glasses inhibited the pentose phosphate oxidative pathway and the glucose 6-phosphate dehydrogenase activity. These effects are ascribable to the fluoride content/release of glass powders, since they were mimicked by NaF solutions and were prevented by dimethyl sulfoxide and tempol (two radical scavengers), by superoxide dismutase (a superoxide scavenger), and by glutathione (the most important intracellular antioxidant molecule), but not by apocynin (an inhibitor of NADPH oxidase). The presence of fluoride-containing glasses and NaF caused also the generation of reactive oxygen species, which was prevented by superoxide dismutase and catalase. The data suggest that fluoride released from glasses is the cause of MG-63 cell oxidative damage and is independent of NADPH oxidase activation. Our data provide a new mechanism to explain F(-) ions toxicity: fluoride could trigger, at least in part, an oxidative stress via inhibition of the pentose phosphate oxidative pathway and, in particular, through the oxidative inhibition of glucose 6-phosphate dehydrogenase.

Binding of prostate-specific membrane antigen to dendritic cells: a critical step in vaccine preparation.

BACKGROUND AIMS: Dendritic cell (DC)-based vaccines hold promise as a safe therapy for prostate cancer (PCa), and prostate-specific membrane antigen (PSMA) fulfils the requirements for a tumor-associated antigen (TAA) to be clinically effective. We evaluated the actual binding of selected HLA-A2-restricted PSMA peptides to HLA class I molecules on ex vivo-generated mature (m) DC. METHODS: mDC were generated from peripheral monocytes of HLA-A2 normal donors. The PSMA peptides PSMA(711) (ALFDIESKV), PSMA(27) (VLAGGFFLL) and PSMA(663) (MMNDQLMFL) were selected based on computer-assisted prediction programs, documented CTL epitope activity or previous use in clinical trials. The model cell line T2 and the clinical grade (CD83+ CCR7+) mDC were pulsed with fluorescein (FL)-conjugated peptides and an anti-HLA-A2 monoclonal antibody (MAb) and analyzed. RESULTS: Flow cytometry analysis showed best binding efficiency to be by PSMA(27.) Confocal microscopy confirmed coincident fluorescence emission of HLA-A2 MAb and FL-PSMA(27). Virtual co-localization of PSMA(27) and HLA class I molecules was supported further by fluorescence resonance energy transfer (FRET) analysis. The clinical relevance of our findings has to be validated in vivo. CONCLUSIONS: The present report is the first to score selected PSMA peptides based on their detectable binding to mDC. It identifies PSMA(27) as the choice candidate among other PSMA peptides and it should be included in developing DC vaccine protocols for HLA-A2 PCa patients.

Immunogenicity of 56 degrees C and UVC-treated prostate cancer is associated with release of HSP70 and HMGB1 from necrotic cells.

BACKGROUND: Prostate hyperthermia and photodynamic therapy can be delivered by a variety of procedures which result in a wide range of temperatures and light energy and cause different kinds of cell death. METHODS: We have addressed the immunogenic effect of heating and UVC irradiation on the prostate cancer (PCa) cell line LNCaP, by studying the release of Danger Associated Molecule Pattern (DAMP) molecules HSP70 and HMGB1 and the dendritic cell (DC) antigen-presenting efficiency. RESULTS: Intracellular upmodulation and extracellular release of HSP70 were inversely correlated. Mild temperatures (43-47 degrees C) induced an early increase of intracellular HSP70, whereas the highest temperature (56 degrees C) induced its extrusion from the cell. Likewise, UVC caused an immediate migration of HSP70 into the cell medium in the absence of any intracellular modulation. 56 degrees C and UVC also induced a robust release of HMGB1. The release of DAMP molecules was closely associated with post-apoptotic membrane damage, as shown by double Annexin V/propidium iodide staining, whereas beta-tubulin, a structural component of cell membranes, was specifically induced by 56 degrees C heating. Tumor uptake strongly impaired the cytokine-driven maturation of DCs and 56 degrees C heating led to a significant recovery of CD83 and CCR7 DC maturation markers, but did not influence the antigen cross-presentation activity. On the contrary, UVC-treated LNCaP had negligible effects on DC maturation, but increased the cross-priming of tumor specific CTL. CONCLUSIONS: These data may be of use in the design of effective non-surgical PCa ablations that combine tumor destruction with long lasting immunity.

Post-apoptotic tumors are more palatable to dendritic cells and enhance their antigen cross-presentation activity.

Critical issues for cytotoxic lymphocyte (CTL) cross-priming are (a) the maturation state of dendritic cells (DC), (b) the source of the tumor-associated antigens (TAA) and (c) the context in which they are delivered to DCs. Drug-induced apoptosis has recently been implicated in CTL cross-priming. However, since drug-treatment produces in vivo more tumor cells than the DC default apoptotic clearance program can cope with, they are expected to proceed to secondary necrosis and change their molecular pattern. Here we have addressed this issue on renal carcinoma cells (RCC) by using different apoptotic stimuli. UVC, but not gamma-irradiation or anthracyclins, induced after 4h treatment of the RCC cell line K1 a combination of apoptotic (phosphatydilserine and calreticulin plasma membrane mobilization) and necrotic (membrane incompetence) features. Heat shock protein (Hsp)-70 and chromatin-bound high mobility box 1 HMGB1 protein, typical of necrosis, were released during the further 20h and thus made accessible to co-cultured monocyte-derived immature (i) DC. UVC-treated, secondary necrotic RCC cell lines were cross-presented with higher efficiency by cytokine-matured (m) DC than their early apoptotic (i.e. gamma-irradiated) counterpart. Upstream events such as increased tumor uptake, activation of genes involved in the antigen-processing machinery, and increased expression of costimulatory and maturation molecules were also observed after loading iDC with secondary necrotic, but not apoptotic, tumor cells. These data offer a description of the molecular and immunogenic characteristics of post-apoptotic tumors which can be exploited to increase the efficiency of in vivo and ex vivo TAA delivery to the DC cross-presentation pathway.

Increased expression of HSP70 by colon cancer cells is not always associated with access to the dendritic cell cross-presentation pathway.

Dendritic cells (DCs) are highly specialized antigen-presenting cells endowed with the unique ability to not only present exogenous antigens upon exposure to MHC II, but also to cross-present these upon exposure to MHC I. This property was exploited to generate the tumor-specific CD8 cytotoxic lymphocyte (CTL) response in DCs-based cancer vaccine protocols. In this context, the source of tumor antigens remains a critical challenge. A crude tumor in the context of danger signals is believed to represent an efficient source of tumor antigens (TAs) for DCs loading. In our previous work, increased DCs cross-presentation of antigens from necrotic gastric carcinoma cells paralleled up-regulation of the heat shock protein hsp70. We studied the expression of hsp70 on primary colon carcinoma cells and its relevance in the cross-priming of anti-tumor CTL by tumor-loaded DCs. Hsp70 was expressed on all three of the tumors studied, but was never detected in the peritumoral normal mucosa (NM). The uptake of the tumor induced a trend towards down-modulation of the monocyte-specific marker CD14, but had no effect on the chemokine receptors CCR4 and CCR7. The IFN-gamma enzyme-linked immunospot assay (ELIspot) showed cross-priming of CTL by tumor-loaded but not NM-loaded DCs in four of the six cases studied. The CTL response generated in DC+tumor cultures was directed towards the tumor, but not towards NM, and it was characterized by refractoriness to polyclonal (Ca ionophores, PKC activators) stimuli. Of the three CTL-generating tumors, only one expressed hsp70. This data indicates a tumor-specific expression of hsp70, but does not support its relevance in the DC cross-presentation of TAs.