Evaluation of the therapeutic potential of ant-TLR4-antibody MTS510 in experimental stroke and significa of different routes of application

Toll-like receptors (TLRs) are central sensors for the inflammatory response in ischemia-reperfusion injury. We therefore investigated whether TLR4 inhibition could be used to treat stroke in a standard model of focal cerebral ischemia. Anti-TLR4/MD2-antibody (mAb clone MTS510) blocked TLR4-induced cell activation in vitro, as reported previously. Here, different routes of MTS510 application in vivo were used to study the effects on stroke outcome up to 2d after occlusion of the middle cerebral artery (MCAO) for 45 min in adult male C57Bl/6 wild-type mice. Improved neurological performance, reduced infarct volumes, and reduced brain swelling showed that intravascular application of MTS510 had a protective effect in the model of 45 min MCAO. Evaluation of potential long-term adverse effects of anti-TLR4-mAb-treament revealed no significant deleterious effect on infarct volumes nor neurological deficit after 14d of reperfusion in a mild model of stroke (15 min MCAO). Interestingly, inhibition of TLR4 resulted in an altered adaptive immune response at 48 hours after reperfusion. We conclude that blocking TLR4 by the use of specific mAb is a promising strategy for stroke therapy. However, long-term studies with increased functional sensitivity, larger sampling sizes and use of other species are required before a clinical use could be envisaged

No association of complement mannose-binding lectin deficiency with cardiovascular disease in patients with Systemic Lupus Erythematosus.

Cardiovascular (CV) morbidity is the major cause of death in patients with Systemic Lupus Erythematosus (SLE). Previous studies on mannose-binding lectin (MBL) gene polymorphisms in SLE patients suggest that low levels of complement MBL are associated with cardiovascular disease (CVD). However, as large studies on MBL deficiency based on resulting MBL plasma concentrations are lacking, the aim of our study was to analyze the association of MBL concentrations with CVD in SLE patients. Plasma MBL levels SLE patients included in the Swiss SLE Cohort Study were quantified by ELISA. Five different CV organ manifestations were documented. Of 373 included patients (85.5% female) 62 patients had at least one CV manifestation. Patients with MBL deficiency (levels below 500 ng/ml or 1000 ng/ml) had no significantly increased frequency of CVD (19.4% vs. 15.2%, P = 0.3 or 17.7% vs. 15.7%, P = 0.7). After adjustment for traditional CV risk factors, MBL levels and positive antiphospholipid serology (APL+) a significant association of CVD with age, hypertension, disease duration and APL+ was demonstrated. In our study of a large cohort of patients with SLE, we could not confirm previous studies suggesting MBL deficiency to be associated with an increased risk for CVD

Epitope-Specific Anti-C1q Autoantibodies in Systemic Lupus Erythematosus

OBJECTIVE: In patients with systemic lupus erythematosus (SLE) complement C1q is frequently targeted by autoantibodies (anti-C1q), that correlate best with active renal disease. Anti-C1q bind to largely unknown epitopes on the collagen-like region (CLR) of this highly functional molecule. Here we aimed at exploring the role of epitope-specific anti-C1q in SLE patients. METHODS: First, 22 sera of SLE patients, healthy controls and anti-C1q positive patients without SLE were screened for anti-C1q epitopes by a PEPperMAP(®) microarray, expressing CLR of C1q derived peptides with one amino acid (AA) shift in different lengths and conformations. Afterwards, samples of 378 SLE patients and 100 healthy blood donors were analyzed for antibodies against the identified epitopes by peptide-based ELISA. Relationships between peptide-specific autoantibodies and SLE disease manifestations were explored by logistic regression models. RESULTS: The epitope mapping showed increased IgG binding to three peptides of the C1q A- and three of the C1q B-chain. In subsequent peptide-based ELISAs, SLE sera showed significantly higher binding to two N-terminally located C1q A-chain peptides than controls (p < 0.0001), but not to the other peptides. While anti-C1q were associated with a broad spectrum of disease manifestations, some of the peptide-antibodies were associated with selected disease manifestations, and antibodies against the N-terminal C1q A-chain showed a stronger discrimination between SLE and controls than conventional anti-C1q. CONCLUSION: In this large explorative study anti-C1q correlate with SLE overall disease activity. In contrast, peptide-antibodies are associated with specific aspects of the disease suggesting epitope-specific effects of anti-C1q in patients with SLE

Identification of the flotillin-1/2 heterocomplex as a target of autoantibodies in bona fide multiple sclerosis

Background: Autoantibodies, in particular those against aquaporin-4 and myelin-oligodendrocyte glycoprotein (MOG), aid as biomarkers in the differential diagnosis of demyelination. Here, we report on discovery of autoantibodies against flotillin in patients with multiple sclerosis (MS). Methods: The target antigen was identified by histo-immunoprecipitation using the patients’ sera and cryosections of rat or pig cerebellum combined with mass spectrometrical analysis. Correct identification was ascertained by indirect immunofluorescence and neutralization tests using the target antigens recombinantly expressed in HEK293 cells. Results: Serum and CSF of the index patient produced a fine-granular IgG indirect immunofluorescence staining of the hippocampal and cerebellar molecular layers. Flotillin-1 and flotillin-2 were identified as target autoantigens. They also reacted with recombinant human flotillin-1/2 co-expressed in HEK293 cells, but not with the individual flotillins in fixed- and live-cell assays. Moreover, neutralization using flotillin-1/2, but not the single flotillins, abolished the tissue reactivity of patient serum. Screening of 521 patients, for whom anti-aquaporin-4 testing was requested and negative, revealed 8 additional patients with anti-flotillin-1/2 autoantibodies. All eight were negative for anti-MOG. Six patients ex post fulfilled the revised McDonald criteria for MS. Vice versa, screening of 538 MS sera revealed anti-flotillin-1/2 autoantibodies in eight patients. The autoantibodies were not found in a cohort of 67 patients with other neural autoantibody-associated syndromes and in 444 healthy blood donors. Conclusions: Autoantibodies against the flotillin-1/2 heterocomplex, a peripheral membrane protein that is involved in axon outgrowth and regeneration of the optic nerve, are present in 1–2% of patients with bona fide MS

High prevalence of anti-C1q antibodies in biopsy-proven active lupus nephritis

BACKGROUND: Anti-C1q antibodies (anti-C1q) have been shown to correlate positively with systemic lupus erythematosus (SLE) nephritis. Several clinical studies indicated a high negative predictive value, suggesting that active lupus nephritis is rarely seen in patients with no anti-C1q. However, the true prevalence of anti-C1q at the time of active lupus nephritis has not been well established. The aim of this study was to determine prospectively the prevalence of anti-C1q in proven active lupus nephritis at the time of the renal biopsy. METHODS: In this prospective multi-centre study, we investigated adult SLE patients undergoing renal biopsy for suspected active lupus nephritis. Serum samples were taken at the time of the biopsy and analysed for the presence of anti-C1q in a standardized way. The activity of lupus nephritis was classified according to the renal histology. Biopsies were also analysed for the presence of glomerular IgG, C1q and C3 deposition. RESULTS: A total of 38 patients fulfilling at least 4/11 American College of Rheumatology (ACR) criteria for the diagnosis of SLE were included. Out of this, 36 patients had proliferative (class II, III or IV) and two had class V lupus nephritis. All but one patient with proliferative lupus nephritis were positive for anti-C1q (97.2%) compared with the 35% of control SLE patients with inactive lupus nephritis and 25% of SLE patients without lupus nephritis ever. All patients were positive for glomerular C1q (36/36) and 37/38 patients had glomerular IgG deposits. Anti-C1q strongly decreased during successful treatment. CONCLUSIONS: Anti-C1q have a very high prevalence in biopsy-proven active lupus nephritis, thus a negative test result almost excludes active nephritis. The data support the hypothesis of a pathogenic role of anti-C1q in lupus nephritis

Tolerance induction through early feeding to prevent food allergy in infants with eczema (TEFFA): rationale, study design, and methods of a randomized controlled trial

BACKGROUND: Up to 8% of all children in industrialized countries suffer from food allergies, whereas children with atopic eczema are affected considerably more frequently. In addition, the type and starting time of weaning foods seem to influence the development of food allergies. However, data from interventional studies on weaning are controversial. The aim of this randomized-controlled clinical trial is to investigate, whether an early introduction of hen's egg (HE), cow's milk (CM), peanut (PN), and hazelnut (HN) in children with atopic eczema can reduce the risk for developing food allergies in the first year of life. METHODS: This is a protocol for a randomized, placebo controlled, double blind, single-center clinical trial. One hundred fifty infants with atopic eczema at 4-8 months of age will be randomized in a 2:1 manner into an active group that will receive rusk-like biscuit powder with HE, CM, PN, and HN (initially approximately 2 mg of each food protein) for 6-8 months or a placebo group, whose participants will receive the same rusk-like biscuit powder without HE, CM, PN, and HN on a daily basis. During the interventional period, the amount of allergens in the study product will be increased three times, each after 6 weeks. All study participants who are sensitized to HE, CM, PN, or HN at the end of the interventional period will undergo an oral food challenge to the respective food in a further visit. Primary endpoint is IgE-mediated food allergy to at least one of the four foods (HE, CM, PN or HN) after 6-8 months of intervention (i.e., at around 1 year of age). Secondary endpoints include multiple food allergies, severity of eczema, wheezing, and sensitization levels against food allergens. DISCUSSION: This clinical trial will assess whether an early introduction of allergenic foods into the diet of children with atopic eczema can prevent the development of food allergies. This trial will contribute to update food allergy prevention guidelines. TRIAL REGISTRATION: German Clinical Trials Register DRKS00016770 . Registered on 09 January 2020

Tolerance induction through non-avoidance to prevent persistent food allergy (TINA) in children and adults with peanut or tree nut allergy: rationale, study design and methods of a randomized controlled trial and observational cohort study

BACKGROUND: Peanuts (PN) and tree nuts (TN) are among the most frequent elicitors of food allergy and can lead to life-threatening reactions. The current advice for allergic patients is to strictly avoid the offending food independently of their individual threshold level, whereas sensitized patients without allergic symptoms should frequently consume the food to avoid (re-)development of food allergy. The aim of this trial is to investigate (I) whether the consumption of low allergen amounts below the individual threshold may support natural tolerance development and (II) to what extent regular allergen consumption in sensitized but tolerant subjects prevents the (re-)development of PN or TN allergy. METHODS: The TINA trial consisting of (part I) a randomized, controlled, open, parallel group, single-center, superiority trial (RCT), and (part II) a prospective observational exploratory cohort study. Children and adults (age 1-67 years) with suspected or known primary PN and/or TN allergy will undergo an oral food challenge (OFC) to determine their clinical reactivity and individual threshold. In the RCT, 120 PN or TN allergic patients who tolerate ≥100 mg of food protein will be randomized (1:1 ratio) to consumption of products with low amounts of PN or TN on a regular basis or strict avoidance for 1 year. The consumption group will start with 1/100 of their individual threshold, increasing the protein amount to 1/50 and 1/10 after 4 and 8 months, respectively. The primary endpoint is the clinical tolerance to PN or TN after 1 year assessed by OFC. In the cohort study, 120 subjects sensitized to PN and/or TN but tolerant are advised to regularly consume the food and observed for 1 year. The primary endpoint is the maintenance of clinical tolerance to PN and/or TN after 1 year assessed by challenging with the former tolerated cumulative dose. DISCUSSION: This clinical trial will help to determine the impact of allergen consumption versus avoidance on natural tolerance development and whether the current dietary advice for PN or TN allergic patients with higher threshold levels is still valid. Trial registration: German Clinical Trials Register; ID: DRKS00016764 (RCT), DRKS00020467 (cohort study). Registered on 15 January 2020, http://www.drks.de

PED/PEA-15 Controls Fibroblast Motility and Wound Closure by ERK1/2-Dependent Mechanisms

Cell migration is dependent on the control of signaling events that play significant roles in creating contractile force and in contributing to wound closure. We evaluated wound closure in fibroblasts from mice overexpressing (TgPED) or lacking ped/pea-15 (KO), a gene overexpressed in patients with type 2 diabetes. Cultured skin fibroblasts isolated from TgPED mice showed a significant reduction in the ability to recolonize wounded area during scratch assay, compared to control fibroblasts. This difference was observed both in the absence and in the presence of mytomicin C, an inhibitor of mitosis. In time-lapse experiments, TgPED fibroblasts displayed about twofold lower velocity and diffusion coefficient, as compared to controls. These changes were accompanied by reduced spreading and decreased formation of stress fibers and focal adhesion plaques. At the molecular level, TgPED fibroblasts displayed decreased RhoA activation and increased abundance of phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2). Inhibition of ERK1/2 activity by PD98059 restored RhoA activation, cytoskeleton organization and cell motility, and almost completely rescued wound closure of TgPED fibroblasts. Interestingly, skin fibroblasts isolated from KO mice displayed an increased wound closure ability. In vivo, healing of dorsal wounds was delayed in TgPED and accelerated in KO mice. Thus, PED/PEA-15 may affect fibroblast motility by a mechanism, at least in part, mediated by ERK1/2. J. Cell. Physiol. 227: 2106–2116, 2012. © 2011 Wiley Periodicals, Inc

Genetic Ablation of Pannexin1 Protects Retinal Neurons from Ischemic Injury

Pannexin1 (Panx1) forms large nonselective membrane channel that is implicated in paracrine and inflammatory signaling. In vitro experiments suggested that Panx1 could play a key role in ischemic death of hippocampal neurons. Since retinal ganglion cells (RGCs) express high levels of Panx1 and are susceptible to ischemic induced injury, we hypothesized that Panx1 contributes to rapid and selective loss of these neurons in ischemia. To test this hypothesis, we induced experimental retinal ischemia followed by reperfusion in live animals with the Panx1 channel genetically ablated either in the entire mouse (Panx1 KO), or only in neurons using the conditional knockout (Panx1 CKO) technology. Here we report that two distinct neurotoxic processes are induced in RGCs by ischemia in the wild type mice but are inactivated in Panx1KO and Panx1 CKO animals. First, the post-ischemic permeation of RGC plasma membranes is suppressed, as assessed by dye transfer and calcium imaging assays ex vivo and in vitro. Second, the inflammasome-mediated activation of caspase-1 and the production of interleukin-1β in the Panx1 KO retinas are inhibited. Our findings indicate that post-ischemic neurotoxicity in the retina is mediated by previously uncharacterized pathways, which involve neuronal Panx1 and are intrinsic to RGCs. Thus, our work presents the in vivo evidence for neurotoxicity elicited by neuronal Panx1, and identifies this channel as a new therapeutic target in ischemic pathologies

Complement in glomerular injury

In recent years, research into the role of complement in the immunopathogenesis of renal disease has broadened our understanding of the fragile balance between the protective and harmful functions of the complement system. Interventions into the complement system in various models of immune-mediated renal disease have resulted in both favourable and unfavourable effects and will allow us to precisely define the level of the complement cascade at which a therapeutic intervention will result in an optimal effect. The discovery of mutations of complement regulatory molecules has established a role of complement in the haemolytic uremic syndrome and membranoproliferative glomerulonephritis, and genotyping for mutations of the complement system are already leaving the research laboratory and have entered clinical practice. These clinical discoveries have resulted in the creation of relevant animal models which may provide crucial information for the development of highly specific therapeutic agents. Research into the role of complement in proteinuria has helped to understand pathways of inflammation which ultimately lead to renal failure irrespective of the underlying renal disease and is of major importance for the majority of renal patients. Complement science is a highly exciting area of translational research and hopefully will result in meaningful therapeutic advances in the near future