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The present study characterizes the oral pharmacokinetics of D-Pinitol, a natural insulin mimetic inositol, in human healthy volunteers (14 males and 11 females). D-Pinitol absorption was studied in (a) subjects receiving a single oral dose of 15 mg/kg (n = 10), or (b) 5 mg/kg pure D-Pinitol (n = 6), and (c) subjects receiving D-Pinitol as part of carbohydrate-containing carob pods-derived syrup with a 3.2% D-Pinitol (Dose of 1600 mg/subject, n = 9). The volunteers received a randomly assigned single dose of either D-Pinitol or carob pod-derived syrup. Blood samples were collected at 0, 15, 30, 45, 60, 90, 120, 180, 240, 360 and 1440 min after intake. Plasma concentration of D-Pinitol was measured and pharmacokinetic parameters obtained. The data indicate that when given alone, the oral absorption of D-Pinitol is dose-dependent and of extended duration, with a Tmax reached after almost 4 h, and a half-life greater than 5 h. When the source of D-Pinitol was a carob pods-derived syrup, Cmax was reduced to 40% of the expected based on the data of D-Pinitol alone, suggesting a reduced absorption probably because of competition with monosaccharide transport. In this group, Tmax was reached before that of D-Pinitol alone, but the estimated half-life remained the same. In the D-Pinitol groups, plasma concentrations of glucose, insulin, glucagon, ghrelin, free fatty acids, and pituitary hormones were additionally measured. A dose of 15 mg/kg of D-Pinitol did not affect glucose levels in healthy volunteers, but reduced insulin and increased glucagon and ghrelin concentrations. D-Pinitol did not increase other hormones known to enhance plasma glucose, such as cortisol or GH, which were surprisingly reduced after the ingestion of this inositol. Other pituitary hormones (gonadotropins, prolactin, and thyroid-stimulating hormone) were not affected after D-Pinitol ingestion. In a conclusion, D-Pinitol is absorbed through the oral route, having an extended half-life and displaying the pharmacological profile of an endocrine pancreas protector, a pharmacological activity of potential interest for the treatment or prevention of insulin resistance-associated conditions.

This work was supported by grants from the following institutions: Grant for international postdoctoral stay. Jose Castillejo Program (Grant CAS15/00257), Ministerio de Educación Cultura y Deporte. Gobierno de España. Proyecto de Investigación en Salud, Consejería de Salud y Familias (Grant PI-0139-2018). EU-ERDF-Instituto de Salud Carlos III (Grant PI19/01577). Proyectos dedesarrollo tecnológico, Ministerio de Ciencia e Innovación (Grant DTS19/00125). Ministerio de Economía, Industria y Competitividad (Grant RTC-2019-007329-1).

Interleukin-6 (IL-6) has emerged as an important mediator of fatty acid metabolism with paradoxical effects in the liver. Administration of IL-6 has been reported to confer protection against steatosis, but plasma and tissue IL-6 concentrations are elevated in chronic liver diseases, including fatty liver diseases associated with obesity and alcoholic ingestion. In this study, we further investigated the role of IL-6 on steatosis induced through a high-fat diet (HFD) in wild-type (WT) and IL-6-deficient (IL-6−/−) mice. Additionally, HFD-fed IL-6−/− mice were also chronically treated with recombinant IL-6 (rIL-6). Obesity in WT mice fed a HFD associated with elevated serum IL-6 levels, fatty liver, upregulation of carnitine palmitoyltransferase 1 (CPT1) and signal transducer and activator of transcription-3 (STAT3), increased AMP kinase phosphorylation (p-AMPK), and downregulation of the hepatic lipogenic enzymes fatty acid synthase (FAS) and stearoyl-CoA desaturase 1 (SCD1). The HFD-fed IL-6−/− mice showed severe steatosis, no changes in CPT1 levels or AMPK activity, no increase in STAT3 amounts, inactivated STAT3, and marked downregulation of the expression of acetyl-CoA carboxylase (ACCα/β), FAS and SCD1. The IL-6 chronic replacement in HFD-fed IL-6−/− mice restored hepatic STAT3 and AMPK activation but also increased the expression of the lipogenic enzymes ACCα/β, FAS and SCD1. Furthermore, rIL-6 administration was associated with aggravated steatosis and elevated fat content in the liver. We conclude that, in the context of HFD-induced obesity, the administration of rIL-6 might contribute to the aggravation of fatty liver disease through increasing lipogenesis., Summary: The administration of rIL-6 might contribute to the aggravation of fatty liver disease through increasing lipogenesis in HFD-induced obesity.

Combination therapy with interferon-alpha (IFNα) and ribavirin is the current treatment of choice for hepatitis C virus (HCV) infection. However, an important number of patients fail to respond to this therapeutic strategy. Factors determining IFN responsiveness are not well understood, and assessment of biomarkers that predict the response to IFN therapy in HCV patients is necessary. Several studies show that particular HCV proteins are able to block IFN function through interaction with important IFN-signal mediators, such as signal transducers and activators of transcription (STATs). We performed immunostaining analysis of STATs in liver tissue from IFN-responder vs. non-responder HCV patients in order to compare the expression profile of these proteins between both groups. Tissue arrays of liver biopsies were used to study the expression of STAT1, STAT2, STAT5 and PIAS1 (protein inhibitor of activated STAT1). Robust and higher expression levels of STAT1, STAT2 and STAT5 in liver tissue from HCV patients were found when compared with samples from healthy donors. However, no significant differences were observed between IFN-responder and -non-responder groups, but rather increasing levels of STAT1, STAT2 and STAT5 paralleled the degree of liver injury. Importantly, PIAS1 expression in the nucleus of most hepatocytes in HCV tissue biopsy sections, particularly of non-responder HCV patients, strongly indicated a regulatory effect on STAT1–DNA binding, likely affecting the IFN late signalling. In conclusion, our evidence indicates that intense PIAS1 nuclear staining, widely distributed in hepatocytes of infected livers, could be a good predictive factor of a defective response to IFN treatment, and a biomarker that is easily detectable by immunostaining during standard histopathological liver biopsy analysis. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Patients infected with hepatitis C virus (HCV) have an impaired response against HCV antigens while keeping immune competence for other antigens. We hypothesized that expression of HCV proteins in infected dendritic cells (DC) might impair their antigen-presenting function, leading to a defective anti-HCV T-cell immunity. To test this hypothesis, DC from normal donors were transduced with an adenovirus coding for HCV core and E1 proteins and these cells (DC-CE1) were used to stimulate T lymphocytes. DC-CE1 were poor stimulators of allogeneic reactions and of autologous primary and secondary proliferative responses. Autologous T cells stimulated with DC-CE1 exhibited a pattern of incomplete activation characterized by enhanced CD25 expression but reduced interleukin 2 production. The same pattern of incomplete lymphocyte activation was observed in CD4+T cells responding to HCV core in patients with chronic HCV infection. However, CD4+response to HCV core was normal in patients who cleared HCV after alpha interferon therapy. Moreover, a normal CD4+response to tetanus toxoid was found in both chronic HCV carriers and patients who had eliminated the infection. Our results suggest that expression of HCV structural antigens in infected DC disturbs their antigen-presenting function, leading to incomplete activation of anti-HCV-specific T cells and chronicity of infection. However, presentation of unrelated antigens by noninfected DC would allow normal T-cell immunity to other pathogens.

Apoptosis is a form of physiological cell death which can be initiated in response to various stimuli including virus infections. We show that vaccinia virus (VV) infection induces apoptosis in an immature B lymphocyte line, WEHI-231. In these cells, several VV-specific proteins were synthesized during the infection, but neither virus production nor viral DNA synthesis were detected. The intracellular levels of the proto-oncogene Bcl-2, which effectively protects cells from programmed cell death, were found to be down-regulated by the VV infection, suggesting that this down-regulation might be involved in the viral induction of apoptosis in WEHI-231 cells. Stable transfectants overexpressing human Bcl-2 were shown to be resistant to the apoptosis produced by the infection, a finding consistent with the proposed role for the down-regulation of endogenous Bcl-2 in VV-induced apoptotic death.

The function of the African swine fever virus (ASFV)bcl-2homologue, geneA179L,in the regulation of apoptosis was investigated using as a model system the human myeloid leukemia cell line K562 induced to die by apoptosis with inhibitors of macromolecular synthesis, a process that is prevented by overexpression of humanbcl-2.It is shown that transfection of K562 cells with the ASFVA179Lgene protects these cells from apoptotic cell death induced by a combination of cycloheximide and actinomycin D or by treatment with cytosine arabinoside. To test the functional role of the highly conserved BH1 domain present in the A179L protein, the Gly residue at position 85 was mutated to Ala, since it has been shown that substitution of the corresponding Gly in human Bcl-2 abrogates its death-repressor activity. It was found that the Gly-to-Ala mutation in the BH1 domain of the viral protein abolished its capacity to protect the K562 cells from apoptosis, indicating that this Gly is essential for A179L action. This finding stresses the functional similarity of the BH1 domains of the viral protein and cellular Bcl-2., This work was 29. Hockenberry, D. M., Oltvai, Z. N., Yin, X.-M., Milliman, C. L., and supported by grants from the Dirección General de Investigación Korsmeyer, S. J., Cell 75, 241 – 251 (1993). Científica y Técnica (PB93-0160-C02-02), the European Community 30. Nguyen, M., Branton, P. E., Walton, P. A., Oltvai, Z. N., Korsmeyer, (AIR-CT93-1332), and Comunidad de Madrid (AE00424/95), and by an S. J., and Shore, G. C., J. Biol. Chem. 269, 16521 – 16524 (1994). institutional grant from Fundacio´n Ramo´n Areces to the Centro de 31. Afonso, C. L., Neilan, J. G., Kutish, G. F., and Rock, D. L., J. Virol. 70, BiologıBa Molecular ‘‘Severo Ochoa.’’

et al., [Background]: LFABP plays a critical role in the uptake and intracellular transport of fatty acids (FA) and other peroxisome proliferator-activated receptor alpha (PPARα) ligands. PPARα activation by PPARα ligands bound to LFABP results in gene expression of FA oxidation enzymes and de novo LFABP. The cytokine IL-6 is involved in regulating liver lipid oxidation. [Aims]: To study the ability of IL-6 to modulate the expression of the LFABP in hepatocytes. Methods: HepG2 and mouse primary hepatocytes were used to test LFABP mRNA and protein expression after IL-6 and PPARα-ligand treatments. Mice lacking IL-6 and wild-type C57Bl/6 were subjected to a fasting/re-feeding cycle to monitor hepatic LFABP mRNA kinetics after food intake. [Results]: In hepatocyte cultures, IL-6 treatment stimulated a LFABP mRNA sustained expression. Combined treatment of IL-6 plus PPARα ligands further enhanced LFABP gene and protein expression. In contrast, pretreatment with the PPARα-antagonist GW-6471 prevented the up-regulation of LFABP mRNA induced by IL-6 in the late phase of LFABP kinetics. Furthermore, the up-regulation of LFABP mRNA observed in the liver of wild-type mice 8 h after re-feeding was absent in mice lacking IL-6. [Conclusions]: IL-6 induces LFABP kinetics in hepatocytes and is partially dependent on PPARα. The maximum increase in LFABP expression occurs when the stimulation with IL-6 and PPARα-ligands takes place simultaneously. The in vivo results indicate a postprandial regulation of LFABP that correlates with the presence of IL-6. These effects may have important implications in the postprandial increase in FA uptake and intracellular trafficking in the liver. © 2013 John Wiley & Sons A/S., This work was supported by Grants PI061109, from the Spanish Institute of Health ‘Carlos III’; TCMR0019, PI0552, PI0236/08, PI0608/10 from the Andalusian Ministry of Health; SAF2012-33283, SAF2010-22113, SAF2010-20521 and CTS-6747/2010; from the Spanish Ministry of Science and Innovation and ‘Centro de Investigacion Biomédica en Red de Diabetes y Enfermedades Metabolicas Asociadas’ (CIBER-DEM), and CIBERobn EU-ERDF(CB06/03/1008). Grants from the European Union’s 7th Framework Programme (Health-F2-2008-223713, REPROBESITY). Elena Baixeras is a tenured investigator through the I3SNS Program of the ‘Andalusian Progreso y Salud Foundation’, Spain.

Apoptosis of natural killer (NK) cells can be induced by non-specific physical damage (UV irradiation, heat shock) or by simultaneous ligation of the CD16 and the interleukin-2 receptor (IL-2R) molecules, but not with either anti-CD16 or IL-2 alone. Whereas blockade of GTP-binding protein (G protein)-mediated signal transduction using ADP-ribosylating bacterial toxins or the GTPase-resistant GTP analog guanosine 5'-0-(3-thiotriphosphate (GTP gamma S) does not affect non-specific induction of NK cell apoptosis, such interventions do inhibit induction of apoptosis by anti-CD16/IL-2. The G proteins involved in the regulation of activation-induced NK apoptosis are sensitive to pertussis toxin (PTX) and to the non-specific GTP analog GTP gamma S but not to cholera toxin, Pseudomonas exotoxin A or diphtheria toxin. A pertussis toxin mutant that lacks ADP-ribosylating activity, but conserves the membrane translocating and T cell-mitogenic effects of the native molecule, fails to inhibit NK apoptosis. To exert their apoptosis-inhibitory effect, PTX and GTP gamma S must be employed before cells are activated. Later addition has no effect, suggesting the implication of G proteins in the transmission of apoptosis-inducing signals, but not in the effector stage of apoptosis. Pre-incubation with PTX or GTP gamma S does not affect the activation of NK cells by CD16 cross-linking, IL-2 stimulation- or both, as assessed by the induction of CD69 expression, protein tyrosine phosphorylation and calcium mobilization. Moreover, neither PTX nor GTP gamma S compromise the effector function of NK cells or the susceptibility of target cells to NK-mediated lysis. These data suggest apoptosis as a novel mechanism by which NK responses may be controlled in vivo, as well as an experimental and therapeutical strategy to counteract endogenous down-regulation of NK responses.

The lymphocyte activation gene 3 (LAG-3), expressed in human activated T and natural killer (NK) cells, is closely related to CD4 at the gene and protein levels. We report here the initial characterization of the LAG-3-encoded protein. We have generated two monoclonal antibodies after immunization of mice with a 30-amino acid peptide that corresponds to an exposed extra loop region present in the LAG-3 immunoglobulin-like first domain. The reactivity of these reagents is directed against LAG-3 since they recognize both membrane-expressed and soluble recombinant LAG-3 molecules produced in a baculovirus expression system. The two antibodies are likely to react with the same or closely related epitope (termed LAG-3.1) exposed on the LAG-3 first domain extra loop, as assessed in competition experiments on LAG-3-expressing activated lymphocytes. Cellular distribution analysis indicated that the LAG-3.1 epitope is expressed on activated T (both CD4+ and CD8+ subsets) and NK cells, and not on activated B cells or monocytes. In immunoprecipitation experiments performed on activated T and NK cell lysates, a 70-kD protein was detected after SDS-PAGE analysis. 45-kD protein species were also immunoprecipitated. Both the 70- and 45-kD proteins were shown to be N-glycosylated. In Western blot analysis, only the former molecule was recognized by the anti-LAG-3 antibodies, demonstrating that it is LAG-3 encoded. These anti-LAG-3 antibodies were used to investigate whether the LAG-3 protein interacts with the CD4 ligands. By using a high-level expression cellular system based on COS-7 cell transfection with recombinant CDM8 vectors and a quantitative cellular adhesion assay, we demonstrate that rosette formation between LAG-3-transfected COS-7 cells and human leukocyte antigen (HLA) class II-bearing B lymphocytes is specifically dependent on LAG-3/HLA class II interaction. In contrast to CD4, LAG-3 does not bind the human immunodeficiency virus gp120. This initial characterization will guide further studies on the functions of this molecule, which may play an important role in immune responses mediated by T and NK lymphocytes.

7 páginas, 3 figuras, 2 tablas., Glucokinase is essential for glucose-stimulated insulin release from the pancreatic beta-cell, serving as glucose sensor in humans. Inactivating or activating mutations of glucokinase lead to different forms of glucokinase disease, i.e. GCK-monogenic diabetes of youth, permanent neonatal diabetes (inactivating mutations), and congenital hyperinsulinism, respectively. Here we present a novel glucokinase gene (GCK)-activating mutation (p.E442K) found in an infant with neonatal hypoglycemia (1.5 mmol/liter) and in two other family members suffering from recurrent hypoglycemic episodes in their childhood and adult life. In contrast to the severe clinical presentation in the index case, functional studies showed only a slight activation of the protein (relative activity index of 3.3). We also report on functional studies of two inactivating mutations of the GCK (p.E440G and p.S441W), contiguous to the activating one, that lead to monogenic diabetes of youth. Interestingly, adult family members carrying the GCK pE440G mutation show an unusually heterogeneous and progressive diabetic phenotype, a feature not typical of GCK-monogenic diabetes of youth. In summary, we identified a novel activating GCK mutation that although being associated with severe neonatal hypoglycemia is characterized by the mildest activation of the glucokinase enzyme of all previously reported, This work was supported by grants (to A.L.C.-M. and N.C.-V.) from Ministerio de Ciencia e Innovación, Dirección General de Investigación Científica y Técnica (SAF2005-08014; SAF2006-12863) and Junta de Andalucía (SAS/PI-024/2007; SAS/PI-0236/2009)

Interferon-alpha5 (IFN-alpha5) is the main IFN-alpha subtype expressed in the liver. Hepatitis C virus (HCV) infection is associated with low IFN-alpha5 mRNA levels, possibly reflecting an escape mechanism of the virus. In this work, we sought to compare IFN-alpha2 and IFN-alpha5 with respect to activation of early cell signaling cascades and induction of antiviral genes in the human hepatoma HepG2 and Huh7 cell lines. We found that the Tyr701 phosphorylation kinetics of Stat1 mediated by IFN stimulation was higher when cells were incubated with IFN-alpha5 than when using IFN-alpha2. Similarly, Tyr(1054/1055) phosphorylation kinetics of Tyk2 were more intense after exposure to IFN-alpha5 than when using IFN-alpha2. Concomitantly, Tyr705 phosphorylation of Stat3 was higher after stimulation with IFN-alpha5 than with IFN-alpha2. In parallel to these findings, the mRNA levels of the antiviral IFN-inducible gene 2',5'-oligoadenylate synthetase were higher in cell samples treated with IFN-alpha5 than with IFN-alpha2. These findings suggest that interaction of IFN-alpha5 and IFN-alpha2 subtypes with IFN type I receptor occurs differently, and this affects the intensity of expression of antiviral genes. In conclusion, our data show that in hepatocytic cells, IFN-alpha5 induces stronger signaling and higher expression of antiviral genes than IFN-alpha2. These data warrant clinical trials to evaluate the efficacy of IFN-alpha5 in chronic viral hepatitis.

Systemic treatment with an anti-ICAM-2 monoclonal antibody (mAb; EOL4G8) eradicates certain established mouse tumors through a mechanism dependent on the potentiation of a CTL-mediated response. However, well-established tumors derived from the MC38 colon carcinoma cell line were largely refractory to this treatment as well as to intratumor injection of a recombinant adenovirus encoding interleukin-12 (IL-12; AdCMVIL-12). We sought to design combined therapy strategies with AdCMVIL-12 plus anti-ICAM-2 mAbs and to identify their mechanism of action.Analysis of antitumor and toxic effects were performed with C57BL/6 mice bearing established MC38 tumors. Anti-ovalbumin T-cell receptor transgenic mice and tumors transfected with this antigen were used for in vitro and in vivo studies on activation-induced cell death (AICD) of CD8(+) T cells.Combined treatment with various systemic doses of EOL4G8 mAb plus intratumor injection of AdCMVIL-12 induced complete regression of MC38 tumors treated 7 days after implantation. Unfortunately, most of such mice succumbed to a systemic inflammatory syndrome that could be prevented if IFN-gamma activity were neutralized once tumors had been rejected. Importantly, dose reduction of EOL4G8 mAb opened a therapeutic window (complete cure of 9 of 18 cases without toxicity). We also show that ICAM-2 ligation by EOL4G8 mAb on activated CTLs prevents AICD, thus extending IFN-gamma production.Combination of intratumor gene transfer of IL-12and systemic anti-ICAM-2 mAb display synergistic therapeutic and toxic effects. CTL life extension resulting from AICD inhibition by anti-ICAM-2 mAbs is the plausible mechanism of action.

While growth hormone (GH) is classically defined as a peptide hormone, recent evidence supports a role for GH acting as a cytokine in the immune system under conditions of stress, counteracting immunosuppression by glucocorticoids. Lymphoid cells express the GH receptor, which belongs to the cytokine receptor superfamily, and GH can be produced by immune tissues, suggesting an autocrine/paracrine mode of action of GH. GH can act as a cytokine, promoting cell cycle progression of lymphoid cells and preventing apoptosis. These effects of GH were shown to be mainly mediated by the PI-3 kinase/Akt pathway and the transcription factor NF-κB. Expression of several cell cycle mediators, as well as Bcl-2, c-Myc and cyclin proteins were found to be regulated by GH. Survival of immune cells under conditions of stress was promoted by NF-κB. Thus, GH acts not only as a hormone but also as a cytokine, playing a potentially important role in immune system cells. Lastly, in this mini-review, we will discuss whether the discovery of these molecules in GH signaling pathways offers new insights into additional mechanisms of action whereby GH regulates apoptosis, proliferation and neoplastic transformation of cells of the immune system.

We have analyzed, in 19 CD3- natural killer cell clones, the genomic organization of the T-cell receptor delta locus with two distinct V delta probes, V delta 1 and V delta 2. These two V delta genes code for surface proteins expressed in more than 90% of peripheral blood T-cell receptor gamma/delta+ lymphocytes, as shown by double color immunofluorescence analysis with anti-TCR delta 1, anti-BB3, and anti-delta TCS1 monoclonal antibodies. The V delta 1 and V delta 2 genes were found to be in germline position in all these clones, which are distinct phenotypically and represent a variety of the corresponding peripheral natural killer cell populations. We also studied in these cloned cell lines the transcriptional activity of the T-cell receptor delta locus with a C delta probe: short transcripts (1.7 and 0.8 kb) were found exclusively. These experiments further suggest that CD3- natural killer peripheral cells are likely to constitute a unique lineage distinct from T lymphocytes.

Using subtractive hybridization of a cDNA library we have identified a human gene, termed LAG-1 (for “Lymphocyte Activation Gene-1”). This cDNA codes for a 69 amino-acid polypeptide which belongs to a new class of recently described proteins secreted by activated lymphocytes and/or monocytes. The LAG-1 gene was cloned, sequenced and its chromosomal location assigned to chromosome 17 (q21 band). The promoter region of the LAG-1 gene was shown to include a GM-CSF-like decanucleotide sequence. Using a baculovirus vector expression system, we found that a 10kDa recombinant LAG-1 protein is secreted by AcNPV infected SF9 cells, as determined in Western blot experiments by the reactivity of specific anti-peptidic heteroantibodies. Finally the natural LAG-1 protein was precipitated from the supernatant of internally labeled activated Nk cells and shown to migrate as a single entity of 14 kDa in SDS-PAGE analysis.