Energy Metabolism in Residents in the Low- and Moderate Altitude Regions of Central Asia with MAFLD and Type 2 Diabetes Mellitus.

The knowledge about the features of energy metabolism in MAFLD in the population living at different climatic and geographic heights is lacking. The goal of this study is to explore the biochemical parameters of blood and erythrocyte energy consumption in patients with MAFLD with and without DM2 living in the low- and moderate-altitude regions of Central Asia. Our study was carried out on patients living in low-altitude mountains: Bishkek, altitude=750-800 m; n=67 (MAFLD with DM 2: n=24; MAFLD without DM2: n=25; control: n=18), and At-Bashy District, Naryn Region, altitude=2046-2300 m; n=58 (MAFLD with DM2: n=28; MAFLD without DM2: n=18; control: n=12). Non-alcoholic fatty liver disease was diagnosed according to history, laboratory tests, liver ultrasound, and exclusion of other liver diseases. The level of liver fibrosis was determined using the FIB-4 score. Blood adenosine 5'-triphosphate (ATP) was determined using the CellTiter-Glo method. Healthy residents living in moderate altitudes have significantly higher levels of cytosolic ATP in their blood (p+≤+0.05) than residents living in low mountains. MAFLD is characterized by an increase in the level of ATP concentration in their blood. ATP concentration decreased significantly in patients with MAFLD with DM2 living in moderate-altitude in comparison to those living in low-altitude mountains. The results suggest that chronic altitude hypoxia leads to a breakdown in adaptive mechanisms of energy metabolism of ATP in patients with MAFLD with type 2 DM.

Drug upgrade: A complete methodology from old drug to new chemical entities using Nematic Protein Organization Technique.

Drug repurposing is used to propose new therapeutic perspectives. Here, we introduce "Drug Upgrade", that is, characterizing the mode of action of an old drug to generate new chemical entities and new therapeutics. We proposed a novel methodology covering target identification to pharmacology validation. As an old drug, we chose hydroxychloroquine (HCQ) for its well-documented clinical efficacy in lupus and its side effect, retinal toxicity. Using the Nematic Protein Organization Technique (NPOT®) followed by liquid chromatography-tandem mass spectrometry analyses, we identified myeloperoxidase (MPO) and alpha-crystallin ß chain (CRYAB) as primary and secondary targets to HCQ from lupus patients' peripheral blood mononuclear cells (PBMCs) and isolated human retinas. Surface plasmon resonance (SPR) and enzymatic assays confirmed the interaction of HCQ with MPO and CRYAB. We synthesized INS-072 a novel analog of HCQ that increased affinity for MPO and decreased binding to CRYAB compared to HCQ. INS-072 delayed cutaneous eruption significantly compared to HCQ in the murine MRL/lpr model of spontaneous lupus and prevents immune complex vasculitis in mice. In addition, long-term HCQ treatment caused retinal toxicity in mice, unlike INS-072. Our study illustrates a method of drug development, where new applications or improvements can be explored by fully characterizing the drug's mode of action.

Vutiglabridin Modulates Paraoxonase 1 and Ameliorates Diet-Induced Obesity in Hyperlipidemic Mice.

Vutiglabridin is a clinical-stage synthetic small molecule that is being developed for the treatment of obesity and its target proteins have not been fully identified. Paraoxonase-1 (PON1) is an HDL-associated plasma enzyme that hydrolyzes diverse substrates including oxidized low-density lipoprotein (LDL). Furthermore, PON1 harbors anti-inflammatory and antioxidant capacities and has been implicated as a potential therapeutic target for treating various metabolic diseases. In this study, we performed a non-biased target deconvolution of vutiglabridin using Nematic Protein Organisation Technique (NPOT) and identified PON1 as an interacting protein. We examined this interaction in detail and demonstrate that vutiglabridin binds to PON1 with high affinity and protects PON1 against oxidative damage. Vutiglabridin treatment significantly increased plasma PON1 levels and enzyme activity but not PON1 mRNA in wild-type C57BL/6J mice, suggesting that vutiglabridin modulates PON1 post-transcriptionally. We further investigated the effects of vutiglabridin in obese and hyperlipidemic LDLR-/- mice and found that it significantly increases plasma PON1 levels, while decreasing body weight, total fat mass, and plasma cholesterol levels. Overall, our results demonstrate that PON1 is a direct, interacting target of vutiglabridin, and that the modulation of PON1 by vutiglabridin may provide benefits for the treatment of hyperlipidemia and obesity.

Functional Molecular Network Analysis Enables Prediction of Response to Vedolizumab Therapy in Anti-TNF Refractory IBD Patients.

BACKGROUND: We applied for the first time 2 label-free technologies, physiological intermolecular modulation spectroscopy (PIMS) and nematic protein organization technic (NPOT) in anti-tumor necrosis factor (TNF) refractory inflammatory bowel disease (IBD) patients to identify clinical responders to vedolizumab therapy and elucidate their underlying functional molecular network. METHODS: PIMS analysis was performed in peripheral blood taken prior to the first vedolizumab application in 20 IBD patients (Crohn disease n = 13; ulcerative colitis n = 7) refractory to at least 1 previous anti-TNF agent therapy. Peripheral blood taken from clinical responders and nonresponders at week 14 of vedolizumab therapy were additionally subjected to NPOT analysis. Response to therapy was assessed by respective clinical disease activity scores (partial Mayo Score and Harvey-Bradshaw Index). RESULTS: Clinical response to vedolizumab treatment was observed in 7 of 13 Crohn disease and 4 of 7 ulcerative colitis patients at week 14. Response to therapy was accurately predicted by PIMS blood analysis in 100% of ulcerative colitis and 77% of Crohn disease patients. Overall prediction of clinical response with PIMS blood analysis was achieved with a 89% positive predictive value and a 82% negative predictive value. NPOT analysis revealed the heightened expression of the proteins ITGB7, ITGAV, ITG3, PF4, and ASGH in the peripheral blood of vedolizumab responders compared to nonresponders. CONCLUSIONS: PIMS analysis of the blood of anti-TNF refractory IBD patients was able to stratify responders to vedolizumab therapy with high accuracy and specificity. NPOT technology could decipher underling molecular networks in the blood of responders, enabling subsequent personalized therapeutic approaches in IBD.

Novel interactomics approach identifies ABCA1 as direct target of evodiamine, which increases macrophage cholesterol efflux.

Evodiamine, a bioactive alkaloid from the fruits of the traditional Chinese medicine Evodia rutaecarpa (Juss.) Benth. (Fructus Evodiae, Wuzhuyu), recently gained attention as a dietary supplement for weight loss and optimization of lipid metabolism. In light of its use by patients and consumers, there is an urgent need to elucidate the molecular targets affected by this natural product. Using a novel interactomics approach, the Nematic Protein Organisation Technique (NPOT), we report the identification of ATP-binding cassette transporter A1 (ABCA1), a key membrane transporter contributing to cholesterol efflux (ChE), as a direct binding target of evodiamine. The binding of evodiamine to ABCA1 is confirmed by surface plasmon resonance (SPR) experiments. Examining the functional consequences of ABCA1 binding reveals that evodiamine treatment results in increased ABCA1 stability, elevated cellular ABCA1 protein levels, and ultimately increased ChE from THP-1-derived human macrophages. The protein levels of other relevant cholesterol transporters, ABCG1 and SR-B1, remain unaffected in the presence of evodiamine, and the ABCA1 mRNA level is also not altered.

KH176 Safeguards Mitochondrial Diseased Cells from Redox Stress-Induced Cell Death by Interacting with the Thioredoxin System/Peroxiredoxin Enzyme Machinery.

A deficient activity of one or more of the mitochondrial oxidative phosphorylation (OXPHOS) enzyme complexes leads to devastating diseases, with high unmet medical needs. Mitochondria, and more specifically the OXPHOS system, are the main cellular production sites of Reactive Oxygen Species (ROS). Increased ROS production, ultimately leading to irreversible oxidative damage of macromolecules or to more selective and reversible redox modulation of cell signalling, is a causative hallmark of mitochondrial diseases. Here we report on the development of a new clinical-stage drug KH176 acting as a ROS-Redox modulator. Patient-derived primary skin fibroblasts were used to assess the potency of a new library of chromanyl-based compounds to reduce ROS levels and protect cells against redox-stress. The lead compound KH176 was studied in cell-based and enzymatic assays and in silico. Additionally, the metabolism, pharmacokinetics and toxicokinetics of KH176 were assessed in vivo in different animal species. We demonstrate that KH176 can effectively reduce increased cellular ROS levels and protect OXPHOS deficient primary cells against redox perturbation by targeting the Thioredoxin/Peroxiredoxin system. Due to its dual activity as antioxidant and redox modulator, KH176 offers a novel approach to the treatment of mitochondrial (-related) diseases. KH176 efficacy and safety are currently being evaluated in a Phase 2 clinical trial.

Chronic bacterial infection activates autoreactive B cells and induces isotype switching and autoantigen-driven mutations.

The links between infections and the development of B-cell-mediated autoimmune diseases are still unclear. In particular, it has been suggested that infection-induced stimulation of innate immune sensors can engage low affinity autoreactive B lymphocytes to mature and produce mutated IgG pathogenic autoantibodies. To test this hypothesis, we established a new knock-in mouse model in which autoreactive B cells could be committed to an affinity maturation process. We show that a chronic bacterial infection allows the activation of such B cells and the production of nonmutated IgM autoantibodies. Moreover, in the constitutive presence of their soluble antigen, some autoreactive clones are able to acquire a germinal center phenotype, to induce Aicda gene expression and to introduce somatic mutations in the IgG heavy chain variable region on amino acids forming direct contacts with the autoantigen. Paradoxically, only lower affinity variants are detected, which strongly suggests that higher affinity autoantibodies secreting B cells are counterselected. For the first time, we demonstrate in vivo that a noncross-reactive infectious agent can activate and induce autoreactive B cells to isotype switching and autoantigen-driven mutations, but on a nonautoimmune background, tolerance mechanisms prevent the formation of consequently dangerous autoimmunity.

Physiological intermolecular modification spectroscopy for the prediction of response to anti-tumor necrosis factor therapy in patients with inflammatory bowel diseases.

BACKGROUND/AIMS: Anti-tumor necrosis factor (TNF) antibodies have clinical efficiency only in a subgroup of patients with inflammatory bowel diseases (IBD). Prediction of clinical response is a critical clinical problem. Physiological intermolecular modification spectroscopy (PIMS) is a label-free technology performed in physiological conditions. PIMS enables real-time monitoring of dynamic molecular resonance of entire proteins and macromolecules of an individual. The aim of this study was to explore the capacity of PIMS to discriminate IBD patients regarding response to anti-TNF treatment. METHODS: Protein extracts of peripheral blood mononuclear cells (PBMC) from 30 outpatients diagnosed with ulcerative colitis (UC) or Crohn's disease (CD) and treated with infliximab were subjected to PIMS analysis in a blinded transversal study. Total protein from each patient's PBMCs was challenged with infliximab. Dynamic changes in macromolecular interaction were registered while the temperature rose from -37 to 37°C. Individual macromolecular volume and molecular elasticity were determined for each patient. RESULTS: Clinical data revealed that 67% of UC and 79% of CD patients responded to infliximab therapy during the 3-month study period based on their respective clinical activity score. These results confirm that PIMS data predicted response to anti-TNF therapy with an accuracy of 96%. CONCLUSION: PIMS stratified IBD patients into two groups, responders and nonresponders, which correlated with the clinical efficacy of anti-TNF therapy. PIMS seems to be a powerful technology to adapt IBD treatment to the individual patient. Further studies with PIMS might enable to predict clinical response to biological treatment in IBD patients before the therapy is initiated.

Anti-melanocortin-4 receptor autoantibodies in obesity.

BACKGROUND: The melanocortin-4 receptor (MC4R) is part of an important pathway regulating energy balance. Here we report the existence of autoantibodies (autoAbs) against the MC4R in sera of obese patients. METHODS: The autoAbs were detected after screening of 216 patients' sera by using direct and inhibition ELISA with an N-terminal sequence of the MC4R. Binding to the native MC4R was evaluated by flow cytometry, and pharmacological effects were evaluated by measuring adenylyl cyclase activity. RESULTS: Positive results in all tests were obtained in patients with overweight or obesity (prevalence, 3.6%) but not in normal weight patients. The selective binding properties of anti-MC4R autoAbs were confirmed by surface plasmon resonance and by immunoprecipitation with the native MC4R. Finally, it was demonstrated that these autoAbs increased food intake in rats after passive transfer via intracerebroventricular injection. CONCLUSION: These observations suggest that inhibitory anti-MC4R autoAbs might contribute to the development of obesity in a small subpopulation of patients.

Immunomodulation by maternal autoantibodies of the fetal serotoninergic 5-HT4 receptor and its consequences in early BALB/c mouse embryonic development.

BACKGROUND: The presence of functional 5-HT4 receptors in human and its involvement in neonatal lupus erythematosus (NLE) have prompted us to study the receptor expression and role during embryogenesis. Earlier we managed to demonstrate that female BALB/c mice immunized against the second extracellular loop (SEL) of the 5-HT4 receptor gave birth to pups with heart block. To explain this phenomenon we investigated the expression of 5-HT4 receptors during mouse embryogenesis. At the same time we looked whether the consequence of 5-HT4 receptor immunomodulation observed earlier is in relation to receptor expression. We studied the expression of 5-HT4 receptor at the mRNA level and its two isoforms 5-HT4(a) and 5-HT4(d) at the protein level in embryos from BALB/c mice, at 8th, 12th, 18th gestation days (GD) and 1 day post natal (DPN). Simultaneously the receptor activity was inhibited by rising antibodies, in female mice against SEL of the receptor. The mice were mated and embryos were collected at 8th, 12th, 18th GD and 1 DPN. RESULTS: 5-HT4 receptor mRNA increased in brain from 12th GD to 1 DPN. Its expression gradually decreased in heart and disappeared at birth. This was consistent with expression of the receptor isoforms 5-HT4(a) and (d). Abnormalities like decreased number of embryos, growth delay, spina bifida and sinus arrhythmia from 12th GD were documented in pups of mice showing anti-5-HT4 receptor antibodies. CONCLUSION: serotoninergic 5-HT4 receptor plays an important role in mouse foetal development. In BALB/c mice there is a direct relation between the expression of receptor and the deleterious effect of maternal anti-5-HT4 receptor autoantibodies in early embryogenesis.

A high-affinity monoclonal antibody with functional activity against the 5-hydroxytryptaminergic (5-HT4) receptor.

Splenocytes from a BALB/c mouse immunised with a synthetic peptide corresponding to the second extracellular loop of the 5-HT4 receptor were fused with SP2/O myeloma cells to produce a monoclonal antibody. The monoclonal antibody was of the IgG2b isotype. The antibody recognised the human 5-HT4(g) (h5-HT4(g)) receptor by immunoblots and by immunofluorescence on chinese hamster ovary (CHO) cells expressing this 5-HT4 receptor isoform. Epitope mapping of the antibody suggested the recognition of a conformational epitope, encompassing the N- and C-terminal fragments of the second extracellular loop. Kinetic experiments using surface plasmon resonance showed that the antibody had a picomolar affinity for its cognate peptide. Inhibition experiments using the same methodology confirmed the specificity of the interaction. The antibody at a concentration of 500 pM competitively inhibited inverse agonist GR113808 binding and showed an inverse agonist effect on the basal activity of CHO cells expressing the 5-HT4(g) receptor. The antibody decreased the effect of 5-HT at 500 and 50 pM concentrations but it increased 5-HT-induced cAMP levels at 5 pM. The dual effect of the monoclonal antibody could be ascribed to mono- or bivalent recognition of the receptor. The antibody described here is the first example of a high-affinity modulator of the 5-HT4 receptor.

Autoantibodies against the serotoninergic 5-HT4 receptor and congenital heart block: a reassessment.

The specificity of autoantibodies against the serotoninergic 5-HT4 receptor in congenital heart block has led to conflicting observations. In order to clarify the situation, a collaborative effort was undertaken to discover the reasons for these discrepancies and to reassess the importance of such autoantibodies by making use of the Research Registry for Neonatal Lupus. Sera from 128 patients (101 anti-SSA/Ro52 positive mothers among which 74 have children with congenital heart block (CHB), 9 anti-SSA/Ro52 negative patients of which 1 had a child with heart block and 18 healthy donors) were assessed in a single blind test using an ELISA coated with a 5-HT4 receptor-derived peptide. Discrepancies between previous observations in our two groups could be ascribed to small differences in the set up of the assay. Of the 75 sera from mothers of children with CHB, 12 were reactive with the 5-HT4 peptide. Four sera among which three were from 35 Ro52 negative mothers without affected children as well as 2 in the 18 controls were positive. Interestingly, in 1 mother with an isolated child with CHB but who had no detectable anti-SSA/Ro52 antibodies and 1 mother with a child with a structural heart block and no detectable antibodies to any component of SSA/Ro, reactivity with the 5-HT4 receptor was noted. While 5-HT4 receptor autoantibodies do not have the predictive value of anti-Ro52 autoantibodies, the presence of these antibodies in a minor subset of mothers whose children have CHB suggests an additional risk factor which may contribute to the pathogenesis of disease.

Effects on heart rate of an anti-M2 acetylcholine receptor immune response in mice.

Autoantibodies in vitro modulating the M2 acetylcholine receptor (M2ACh-R) were observed in patients with idiopathic dilated cardiomyopathy (IDC) or Chagas' cardiomyopathy (ChC). We investigated the in vivo consequences on heart rate of such antibodies in mice immunized with a peptide derived from the second extracellular loop of the M2ACh-R compared with mice immunized with an irrelevant peptide. Sera of mice immunized with the M2ACh-R-derived peptide recognized the M2ACh-R on immunoblots and enhanced agonist activity of carbachol toward the M2AChR transfected in CHO cells. In vivo, no difference could be shown in heart rate or heart rate variability between the two groups of mice. The decrease in heart rate induced by carbachol was more pronounced, however, in the M2ACh-R immunized mice. The increase in heart rate induced by atropine, gallamine, and isoproterenol was significantly attenuated in the M2ACh-R immunized mice. Analysis of heart rate variability further argued for an increased parasympathetic response to different drugs in the M2ACh-R immunized mice. Antibodies raised against the M2AChR can behave as positive M2AChR allosteric modulators in vivo. They might be protective in boosting the activity of the parasympathetic drive to the heart, especially in patients with a high sympathetic tone.

A peptide vaccine administered transcutaneously together with cholera toxin elicits potent neutralising anti-FMDV antibody responses.

In this study a synthetic peptide representing residues 141-159 from the GH loop of VP1 protein of foot-and-mouth disease virus was tested for its capacity to elicit virus neutralising antibodies in mice after transcutaneous immunisation. Topical application of the peptide conjugated to bovine serum albumin together with cholera toxin as an adjuvant elicited anti-peptide antibody responses with strong virus neutralising activity. The combination of cholera toxin with an immunostimulatory CpG motif resulted in the induction of IgG1 and IgG2a anti-peptide antibodies with significantly enhanced virus neutralising activity. To shed more light on the mechanisms of cholera toxin adjuvanticity we demonstrated its binding to keratinocytes via GM(1)-gangliosides. This was followed by an increase of the intracellular cAMP and the rapid diffusion of cholera toxin throughout the epidermis. These findings demonstrate that peptide-based vaccines when combined with the appropriate adjuvant(s) can elicit potent virus neutralising antibody responses after transcutaneous immunisation. However, experiments in target species will be required to confirm the potential of this simple vaccination procedure in livestock.

Characterisation and application of antibodies specific for the long platelet-derived growth factor A and B chains.

The platelet-derived growth factor (PDGF) family comprises important mitogens for mesenchymal cells. The active dimeric form of PDGF consists of four structurally related A, B, C, and D chains. All PDGF-variants bind to PDGF-receptors. The A and B chains occur with and without basic C-terminal amino acid extensions as long (A(L) and B(L)) and short (A(S) and B(S)) isoforms. PDGF-A and -B form homo- or heterodimers. The biological relevance of short and long isoforms is unknown, although it may relate to different affinities for glycosaminoglycans of the cell glycocalix and intercellular matrix. Commercially available anti-PDGF-A and anti-PDGF-B antibodies cannot discriminate between the short and the long isoforms. Thus, to investigate the function of the long and short isoforms, we raised antibodies specific for the long A and B chain isoforms. The antibodies were affinity-purified and their properties analysed by surface plasmon resonance. Inhibition studies with different PDGF homodimers and dot-blot studies proved their high specificity for the respective isoforms. Both antibodies recognised the target PDGF homodimers complexed to the glycocalix of human arterial smooth muscle cells and human monocyte-derived macrophages. By using these specific antibodies, we were able to confirm at the protein level the synthesis of PDGF-A and -B during differentiation of human monocyte-derived macrophages and to demonstrate the presence of the PDGF-A(L) and PDGF-B(L) isoforms in human arterial tissue.

scFv single chain antibody variable fragment as inverse agonist of the beta2-adrenergic receptor.

Antibodies directed against the second extracellular loop of G protein-coupled receptors were shown to possess functional activities. Using a functional monoclonal antibody against the human beta2-adrenergic receptor, a scFv fragment with high affinity for the target epitope was constructed and produced. The fragment recognized the beta2-adrenergic receptors on A431 cells, blocked cAMP accumulation induced by the beta2-agonist salbutamol, and decreased basal cAMP accumulation in the same cells. Their in vitro activity was tested on neonatal rat cardiomyocytes. The antibody fragments blocked the chronotropic activity induced by the beta2-agonist clenbuterol. They also decreased the in vivo heart beating frequency of mice pretreated with bisoprolol (a beta1-adrenergic receptor antagonist) for 4 min after injection. The immunological approach presented here may serve as a strategy for the synthesis of a new class of allosteric modulators for G protein-coupled receptors.