Total chemical synthesis and chemotactic activity of human S100A12 (EN-RAGE)

The role of fecal biomarkers in individuals with inflammatory bowel disease

INTRODUCTION

Inflammatory bowel disease (IBD), encompassing Crohn's disease (CD) and Ulcerative Colitis (UC), is a relapsing and remitting condition. Noninvasive biomarkers have an increasingly important role in the diagnosis of IBD and in the prediction of future disease course in individuals with IBD. Strategies for the management of IBD increasingly rely upon close monitoring of gastrointestinal inflammation.

AREAS COVERED

This review provides an update on the current understanding of established and novel stool-based biomarkers in the diagnosis and management of IBD. It also highlights key gaps, identifies limitations, and advantages of current markers, and examines aspects that require further study and analysis.

EXPERT OPINION

Current noninvasive inflammatory markers play an important role in the diagnosis and management of IBD; however, limitations exist. Future work is required to further characterize and validate current and novel markers of inflammation. In addition, it is essential to better understand the roles and characteristics of noninvasive markers to enable the appropriate selection to accurately determine the condition of the intestinal mucosa.

KCD: A prediction web server of knowledge-based circular dichroism

We present a web server that predicts the far-UV circular dichroism (CD) spectra of proteins by utilizing their three-dimensional (3D) structures from the Protein Data Bank (PDB). The main algorithm is based on the classical theory of optical activity together with a set of atomic complex polarizabilities, which are obtained from the analysis of a series of synchrotron radiation CD spectra and their related 3D structures from the PDB. The results of our knowledge-based CD method (KCD) are in good agreement with measured spectra that could include the effect of D-amino acids. Our method also delivers some of the most accurate predictions, in comparison with the calculated spectra from well-established models. Specifically, using a metric of closeness based on normalized absolute deviations between experimental and calculated spectra, the mean values for a series of 57 test proteins give the following figures for such models: 0.26 KCD, 0.27 PDBMD2CD, 0.30 SESCA, and 0.47 DichroCalc. From another point of view, it is worth mentioning the remarkable capabilities of the recent approaches based on artificial intelligence, which can precisely predict the native structure of proteins. The structure of proteins, however, is flexible and can be modified by a diversity of environmental factors such as interactions with other molecules, mechanical stresses, variations of temperature, pH, or ionic strength. Experimental CD spectra together with reliable predictions can be utilized to assess eventual secondary structural changes. A similar kind of evaluation can be done for the case of an incomplete protein structure that has been reconstructed by using different approaches. The KCD method can be freely accessed from: https://kcd.cinvestav.mx/.

Pathogenic role of S100 proteins in psoriasis

Psoriasis is a chronic inflammatory skin disease. The histopathological features of psoriasis include excessive proliferation of keratinocytes and infiltration of immune cells. The S100 proteins are a group of EF-hand Ca2+-binding proteins, including S100A2, -A7, -A8/A9, -A12, -A15, which expression levels are markedly upregulated in psoriatic skin. These proteins exert numerous functions such as serving as intracellular Ca2+ sensors, transduction of Ca2+ signaling, response to extracellular stimuli, energy metabolism, and regulating cell proliferation and apoptosis. Evidence shows a crucial role of S100 proteins in the development and progress of inflammatory diseases, including psoriasis. S100 proteins can possibly be used as potential therapeutic target and diagnostic biomarkers. This review focuses on the pathogenic role of S100 proteins in psoriasis.

Top-Down Proteomics Detection of Potential Salivary Biomarkers for Autoimmune Liver Diseases Classification

(1) Autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) are autoimmune liver diseases characterized by chronic hepatic inflammation and progressive liver fibrosis. The possible use of saliva as a diagnostic tool has been explored in several oral and systemic diseases. The use of proteomics for personalized medicine is a rapidly emerging field. (2) Salivary proteomic data of 36 healthy controls (HCs), 36 AIH and 36 PBC patients, obtained by liquid chromatography/mass spectrometry top-down pipeline, were analyzed by multiple Mann-Whitney test, Kendall correlation, Random Forest (RF) analysis and Linear Discriminant Analysis (LDA); (3) Mann-Whitney tests provided indications on the panel of differentially expressed salivary proteins and peptides, namely cystatin A, statherin, histatin 3, histatin 5 and histatin 6, which were elevated in AIH patients with respect to both HCs and PBC patients, while S100A12, S100A9 short, cystatin S1, S2, SN and C showed varied levels in PBC with respect to HCs and/or AIH patients. RF analysis evidenced a panel of salivary proteins/peptides able to classify with good accuracy PBC vs. HCs (83.3%), AIH vs. HCs (79.9%) and PBC vs. AIH (80.2%); (4) RF appears to be an attractive machine-learning tool suited for classification of AIH and PBC based on their different salivary proteomic profiles.

Characterization of S100A12 from nile tilapia (Oreochromis niloticus) and its roles on inflammatory responses

S100A12 is a member of S100 proteins family that induces pro-inflammatory response via ligating with the receptor for advanced glycation end products (RAGE) and subsequent activation of intracellular signal transduction pathways. But information about fish S100A12 remain largely unclear. In this study, the S100A12 homolog (On-S100A12) was identified from Nile tilapia (Oreochromis niloticus). On-S100A12 was mainly expressed in liver and intestine. After Streptococcus agalactiae infection in vivo, S100A12 significantly increased in brain, intestine, liver and head kidney, suggesting S100A12 might played roles in immune response. The further in vitro experiments found that recombinant protein of S100A12 (rOn-S100A12) upregulated the expression of IL1-β, TLR2, TNF-α and inhibited the expression of IL-10, indicating On-S100A12 promoted inflammatory response and activation of M1 macrophages. The present data lay a foundation to further explore the roles of fish S100 during immune defense and will also be beneficial for better understanding of fish immune-regulatory network.

Salivary Proteomics Reveals Significant Changes in Relation to Alzheimer's Disease and Aging

BACKGROUND

Aging is a risk factor for several pathologies as Alzheimer's disease (AD). Great interest exists, therefore, in discovering diagnostic biomarkers and indicators discriminating biological aging and health status. To this aim, omic investigations of biological matrices, as saliva, whose sampling is easy and non-invasive, offer great potential.

OBJECTIVE

Investigate the salivary proteome through a statistical comparison of the proteomic data by several approaches to highlight quali-/quantitative variations associated specifically either to aging or to AD occurrence, and, thus, able to classify the subjects.

METHODS

Salivary proteomic data of healthy controls under-70 (adults) and over-70 (elderly) years old, and over-70 AD patients, obtained by liquid chromatography/mass spectrometry, were analyzed by multiple Mann-Whitney test, Kendall correlation, and Random-Forest (RF) analysis.

RESULTS

Almost all the investigated proteins/peptides significantly decreased in relation to aging in elderly subjects, with or without AD, in comparison with adults. AD subjects exhibited the highest levels of α-defensins, thymosin β4, cystatin B, S100A8 and A9. Correlation tests also highlighted age/disease associated differences. RF analysis individuated quali-/quantitative variations in 20 components, as oxidized S100A8 and S100A9, α-defensin 3, P-B peptide, able to classify with great accuracy the subjects into the three groups.

CONCLUSION

The findings demonstrated a strong change of the salivary protein profile in relation to the aging. Potential biomarkers candidates of AD were individuated in peptides/proteins involved in antimicrobial defense, innate immune system, inflammation, and in oxidative stress. RF analysis revealed the feasibility of the salivary proteome to discriminate groups of subjects based on age and health status.

Knowledge-Based Atomic Polarizabilities Used to Model Circular Dichroism Spectra of Proteins

We present a model of circular dichroism for proteins, which is mainly based on both the classical theory of optical activity and a series of effective atomic polarizabilities. Such polarizabilities are extracted from the analysis of a set of synchrotron radiation circular dichroism spectra and their corresponding three-dimensional structures from the Protein Data Bank. Each modeled spectrum is obtained from the protein atomic coordinates and the identification of its secondary structure elements. The resulting spectra are in good agreement with additional experimental data and also with the predictions of some other models. Among them, only our approach is able to describe the effect of d-amino acids. Moreover, our model is also utilized to evaluate protein reconstructions as well as structural changes.

The alarmin S100A12 causes sterile inflammation of the human chorioamniotic membranes as well as preterm birth and neonatal mortality in mice†

Sterile inflammation is triggered by danger signals, or alarmins, released upon cellular stress or necrosis. Sterile inflammation occurring in the amniotic cavity (i.e. sterile intra-amniotic inflammation) is frequently observed in women with spontaneous preterm labor resulting in preterm birth, the leading cause of neonatal morbidity and mortality worldwide; this condition is associated with increased amniotic fluid concentrations of alarmins. However, the mechanisms whereby alarmins induce sterile intra-amniotic inflammation are still under investigation. Herein, we investigated the mechanisms whereby the alarmin S100A12 induces inflammation of the human chorioamniotic membranes in vitro and used a mouse model to establish a causal link between this alarmin and adverse perinatal outcomes. We report that S100A12 initiates sterile inflammation in the chorioamniotic membranes by upregulating the expression of inflammatory mediators such as pro-inflammatory cytokines and pattern recognition receptors. Importantly, S100A12 induced the priming and activation of inflammasomes, resulting in caspase-1 cleavage and the subsequent release of mature IL-1β by the chorioamniotic membranes. This alarmin also caused the activation of the chorioamniotic membranes by promoting MMP-2 activity and collagen degradation. Lastly, the ultrasound-guided intra-amniotic injection of S100A12 at specific concentrations observed in the majority of women with sterile intra-amniotic inflammation induced preterm birth (rates: 17% at 200 ng/sac; 25% at 300 ng/sac; 25% at 400 ng/sac) and neonatal mortality (rates: 22% at 200 ng/sac; 44% at 300 ng/sac; 31% at 400 ng/sac), thus demonstrating a causal link between this alarmin and adverse perinatal outcomes. Collectively, our findings shed light on the inflammatory responses driven by alarmins in the chorioamniotic membranes, providing insight into the immune mechanisms leading to preterm birth in women with sterile intra-amniotic inflammation.

Global Studies of Using Fecal Biomarkers in Predicting Relapse in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract mainly comprising two forms including Crohn's disease (CD) and ulcerative colitis (UC). IBD is a lifelong relapsing remitting disease and relapses occur at random patterns which are unpredictable. Fecal biomarkers have been increasingly used to assess disease activity in IBD due to their positive correlations with intestinal inflammation. Recent studies have also assessed the use of fecal biomarkers in predicting relapse and post-operative recurrence. This review provides information from global studies of using fecal calprotectin, lactoferrin and S100A12 to predict relapse in IBD. Strategies for further studies and the use of these fecal biomarkers for personalized management in IBD are also discussed.

S100A12 in Digestive Diseases and Health: A Scoping Review

Calgranulin proteins are an important class of molecules involved in innate immunity. These members of the S100 class of the EF-hand family of calcium-binding proteins have numerous cellular and antimicrobial functions. One protein in particular, S100A12 (also called EN-RAGE or calgranulin C), is highly abundant in neutrophils during acute inflammation and has been implicated in immune regulation. Structure-function analyses reveal that S100A12 has the capacity to bind calcium, zinc, and copper, processes that contribute to nutritional immunity against invading microbial pathogens. S100A12 is a ligand for the receptor for advanced glycation end products (RAGE), toll-like receptor 4 (TLR4), and CD36, which promote cellular and immunological pathways to alter inflammation. We conducted a scoping review of the existing literature to define what is known about the association of S100A12 with digestive disease and health. Results suggest that S100A12 is implicated in gastroenteritis, necrotizing enterocolitis, gastritis, gastric cancer, Crohn's disease, irritable bowel syndrome, inflammatory bowel disease, and digestive tract cancers. Together, these results reveal S100A12 is an important molecule broadly associated with the pathogenesis of digestive diseases.

Plasma S100A8/A9 heterodimer is an early prognostic marker of acute kidney injury associated with cardiac surgery

AIM

We investigated whether plasma levels of the inflammation marker S100A8/A9, could predict acute kidney injury (AKI) onset in patients undergoing cardiac surgery necessitating cardiopulmonary bypass (CPB).

PATIENTS & METHODS

Plasma levels of S100A8/A9 and other neutrophil cytosolic proteins were measured in 39 patients pre- and immediately post-CPB.

RESULTS

All markers increased significantly post-CPB with S100A8/A9, S100A12 and myeloperoxidase levels significantly higher in patients who developed AKI within 7 days. S100A8/A9 had good prognostic utility for AKI, with an area under the receiver operating characteristic curve of 0.81 (95% CI: 0.676-0.949) and a cut-off value of 10.6 μg/ml (85.7% sensitivity and 75% specificity) irrespective of age.

CONCLUSION

Plasma S100A8/A9 levels immediately after cardiac surgery, can predict onset of AKI, irrespective of age.

Effect of selected gastrointestinal parasites and viral agents on fecal S100A12 concentrations in puppies as a potential comparative model

BACKGROUND

Previous data suggest that fecal S100A12 has clinical utility as a biomarker of chronic gastrointestinal inflammation (idiopathic inflammatory bowel disease) in both people and dogs, but the effect of gastrointestinal pathogens on fecal S100A12 concentrations is largely unknown. The role of S100A12 in parasite and viral infections is also difficult to study in traditional animal models due to the lack of S100A12 expression in rodents. Thus, the aim of this study was to evaluate fecal S100A12 concentrations in a cohort of puppies with intestinal parasites (Cystoisospora spp., Toxocara canis, Giardia sp.) and viral agents that are frequently encountered and known to cause gastrointestinal signs in dogs (coronavirus, parvovirus) as a comparative model.

METHODS

Spot fecal samples were collected from 307 puppies [median age (range): 7 (4-13) weeks; 29 different breeds] in French breeding kennels, and fecal scores (semiquantitative system; scores 1-13) were assigned. Fecal samples were tested for Cystoisospora spp. (C. canis and C. ohioensis), Toxocara canis, Giardia sp., as well as canine coronavirus (CCV) and parvovirus (CPV). S100A12 concentrations were measured in all fecal samples using an in-house radioimmunoassay. Statistical analyses were performed using non-parametric 2-group or multiple-group comparisons, non-parametric correlation analysis, association testing between nominal variables, and construction of a multivariate mixed model.

RESULTS

Fecal S100A12 concentrations ranged from < 24-14,363 ng/g. Univariate analysis only showed increased fecal S100A12 concentrations in dogs shedding Cystoisospora spp. (P = 0.0384) and in dogs infected with parvovirus (P = 0.0277), whereas dogs infected with coronavirus had decreased fecal S100A12 concentrations (P = 0.0345). However, shedding of any single enteropathogen did not affect fecal S100A12 concentrations in multivariate analysis (all P > 0.05) in this study. Only fecal score and breed size had an effect on fecal S100A12 concentrations in multivariate analysis (P < 0.0001).

CONCLUSIONS

An infection with any single enteropathogen tested in this study is unlikely to alter fecal S100A12 concentrations, and these preliminary data are important for further studies evaluating fecal S100A12 concentrations in dogs or when using fecal S100A12 concentrations as a biomarker in patients with chronic idiopathic gastrointestinal inflammation.

An update on diagnostic and prognostic biomarkers in inflammatory bowel disease

INTRODUCTION

Diagnosis of the chronic inflammatory bowel diseases relies upon initial recognition of an inflammatory condition, followed by definitive endoscopic, histological and radiological investigations. Various biomarkers are available to assist with initial elucidation of an inflammatory process: these also have important roles after diagnosis in monitoring and ongoing assessment of progress. Areas covered: Various inflammatory markers, serological tests and genetic analyses may be helpful in predicting the course of disease in the coming months. This review provides an update on the current understanding and knowledge about these markers. It also highlights key gaps and identifies aspects that require further study. Expert commentary: Our current approach to the application of non-invasive biomarkers is rudimentary. Further work is required to elucidate the roles of the various markers.

Fecal biomarkers in inflammatory bowel disease: how, when and why?

Over the last thirty years knowledge on fecal biomarkers (FM) has substantially increased. Nowadays these non-invasive inflammation markers are used in the daily management of inflammatory bowel disease (IBD). The interest in investigating FM was motivated by the need of a simple, quick, disposable and less invasive marker of disease activity, which might remove the need for endoscopy when following up with patients. Areas covered: Current literature was reviewed for articles regarding the role of FM in IBD diagnosis, activity, flare prediction, medication and surgical treatment response as well as how FM may differ in adult and paediatric IBD patient populations. Expert commentary: Although FM is relevant in IBD patient follow-up, there isn't enough data regarding FM reference values for different ages, different disease subtypes, disease localization/extension or response to therapy. Serial measurements of FM for each patient may be useful in accessing relapse in most patients. FM presented more consistent results when used as a predictive tool of relapse after ileocecal surgery in Crohn's disease. Ongoing research will clarify FM role in decision-making IBD daily practice.

Fecal biomarkers in inflammatory bowel disease

Over the last two decades, knowledge on fecal biomarkers has substantially increased. Nowadays, these non-invasive markers of inflammation have significant clinical utility in the management of inflammatory bowel disease. Their use informs the decision to perform endoscopy before diagnosis is made right through to influencing therapeutic choices and the need for interval endoscopic assessment. In this review, the roles of two S100 proteins, calprotectin, and S100A12 are described along with that of lactoferrin, in the context of inflammatory bowel disease.

An orthologue of the host-defense protein psoriasin (S100A7) is expressed in frog skin

Host-defense peptides and proteins are vital for first line protection against bacteria. Most host-defense peptides and proteins common in vertebrates have been studied primarily in mammals, while their orthologues in non-mammalian vertebrates received less attention. We found that the European Common Frog Rana temporaria expresses a protein in its skin that is evolutionarily related to the host-defense protein S100A7. This prompted us to test if the encoded protein, which is an important microbicidal protein in human skin, shows similar activity in frogs. The R. temporaria protein lacks the zinc-binding sites that are key to the antimicrobial activity of human S100A7 at neutral pH. However, despite being less potent, the R. temporaria protein does compromise bacterial membranes at low pH, similar to its human counterpart. We postulate that, while amphibian S100A7 likely serves other functions, the capacity to compromise bacterial cell membranes evolved early in tetrapod evolution.

Expression of Calgranulin Genes S100A8, S100A9 and S100A12 Is Modulated by n-3 PUFA during Inflammation in Adipose Tissue and Mononuclear Cells

Calgranulin genes (S100A8, S100A9 and S100A12) play key immune response roles in inflammatory disorders, including cardiovascular disease. Long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) may have systemic and adipose tissue-specific anti-inflammatory and cardio-protective action. Interactions between calgranulins and the unsaturated fatty acid arachidonic acid (AA) have been reported, yet little is known about the relationship between calgranulins and the LC n-3 PUFA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). We explored tissue-specific action of calgranulins in the setting of evoked endotoxemia and n-3 PUFA supplementation. Expression of calgranulins in adipose tissue in vivo was assessed by RNA sequencing (RNASeq) before and after n-3 PUFA supplementation and evoked endotoxemia in the fenofibrate and omega-3 fatty acid modulation of endotoxemia (FFAME) Study. Subjects received n-3 PUFA (n = 8; 3600mg/day EPA/DHA) or matched placebo (n = 6) for 6–8 weeks, before completing an endotoxin challenge (LPS 0.6 ng/kg). Calgranulin genes were up-regulated post-LPS, with greater increase in n-3 PUFA (S100A8 15-fold, p = 0.003; S100A9 7-fold, p = 0.003; S100A12 28-fold, p = 0.01) compared to placebo (S100A8 2-fold, p = 0.01; S100A9 1.4-fold, p = 0.4; S100A12 5-fold, p = 0.06). In an independent evoked endotoxemia study, calgranulin gene expression correlated with the systemic inflammatory response. Through in vivo and in vitro interrogation we highlight differential responses in adipocytes and mononuclear cells during inflammation, with n-3 PUFA leading to increased calgranulin expression in adipose, but decreased expression in circulating cells. In conclusion, we present a novel relationship between n-3 PUFA anti-inflammatory action in vivo and cell-specific modulation of calgranulin expression during innate immune activation.

Fecal S100A12 concentration predicts a lack of response to treatment in dogs affected with chronic enteropathy

S100A12 is a potential biomarker of gastrointestinal inflammation in dogs and fecal S100A12 concentrations are correlated with disease severity and outcome. The aim of the present study was to investigate whether there was any association between pre-treatment fecal S100A12 concentrations in dogs affected with chronic enteropathy (CE) and the response to treatment. Dogs affected with CE were recruited into the study and were classified as antibiotic-responsive diarrhea (ARD; n = 9), food-responsive diarrhea (FRD; n = 30) or idiopathic inflammatory bowel disease (IBD; n = 25). They were also grouped based on their response to treatment as complete remission (n = 35), partial response (n = 25) or no response (n = 4). Fecal S100A12 concentrations, measured by ELISA, were elevated in dogs affected with IBD compared with those from dogs affected with FRD (P = 0.010) or ARD (P = 0.025). Dogs with IBD that did not respond to treatment (n = 4) had significantly greater fecal S100A12 concentrations than dogs in complete remission (P = 0.009). Measurement of fecal S100A12 at the time of diagnosis discriminated between dogs with IBD that were refractory to therapy (≥2700 ng/g fecal S100A12) from those with at least a partial response (<2700 ng/g fecal S100A12), with a sensitivity of 100% and a specificity of 76%. These preliminary results suggest that testing of fecal S100A12 may be useful for predicting the lack of response to treatment in dogs affected with CE. The utility of serial fecal S100A12 measurements for monitoring dogs undergoing treatment for CE warrants further investigation.

S100A12 concentrations and myeloperoxidase activity in the intestinal mucosa of healthy dogs

BACKGROUND

Relatively few laboratory markers have been evaluated for the detection or monitoring of intestinal inflammation in canine chronic enteropathies, including inflammatory bowel disease (IBD). Previous research found that the intestinal mucosal levels of S100A12 and myeloperoxidase (MPO), as biomarkers of gut inflammation, were elevated in human patients with IBD. To date, the S100A12 and MPO levels in intestinal mucosal samples from either healthy dogs or from dogs suffering from IBD remain unreported. Therefore, this study aimed to evaluate the mucosal S100A12 and MPO levels in four different parts of the intestine (duodenum, jejunum, ileum and colon) in 12 healthy laboratory Beagle dogs using the ELISA and spectrophotometric methods, respectively.

RESULTS

Based on histological examinations, the recorded findings for all the samples were considered normal. The mucosal concentration of S100A12 in the ileum was significantly higher than in all other segments of the intestine (p < 0.05). MPO activity was significantly higher in the ileal, jejunal and duodenal than in colonic mucosal samples (p < 0.05). Moreover, its concentration was higher in the jejunum than in the duodenum.

CONCLUSIONS

This study showed that S100A12 and MPO are reliably detectable in canine intestinal mucosa. The assays used appeared to be sufficient to further evaluate the role of S100A12 and MPO in the pathogenesis of canine chronic enteropathies, including IBD. These biomarkers may play a role in the initial detection of gut inflammation suggesting the need for further investigations to confirm IBD or to differentiate between IBD subtypes. Understanding the role of S100A12 and MPO in the pathogenesis of chronic intestinal inflammation in future may result in an improved understanding of canine chronic intestinal inflammation.

Do elevated plasma S100A12 levels predict atherosclerosis in peritoneal dialysis patients?

AIM

Atherosclerotic cardiovascular disease is one of the major causes of mortality and morbidity in peritoneal dialysis (PD) patients. S100A12 is an endogenous receptor ligand of advanced glycation end-products. It was shown to contribute to the development of atherosclerosis in animal models. The aim of this study was to evaluate the relationship between S100A12 levels and carotid atherosclerosis in PD patients.

METHODS

A cross-sectional study was performed in 56 PD patients and 20 control subjects. Plasma S100A12 levels were measured from all participants beside routine laboratory evaluation. All subjects underwent high-resolution B-mode ultrasonography to determine carotid intima media thickness (CIMT). S100A12 levels were compared between patient and control groups. Correlation analyses of S100A12 with other laboratory values and CIMT were also performed.

RESULTS

Plasma S100A12 levels were higher in PD patients compared with control subjects (129.5 ± 167.2 ng/mL vs. 48.5 ± 30.3 ng/mL, respectively, p < 0.001). In the patient group, CIMT was found to be positively correlated with age (r = 0.354; p = 0.007), CRP level (r = 0.269; p = 0.045), and S100A12 (r = 0.293; p = 0.028) level while it was found to be negatively correlated with hemoglobin concentration (r = -0.264; p = 0.049). In the linear regression analysis, the model, including CRP, S100A12, age, and Hgb, was found to be significant (F: 4.177, p: 0.005). When the parameters are analyzed age and S100A12 were found to be independent determinants of CIMT (β = 0.308, p = 0.018 and β = 0.248, p = 0.049, respectively).

CONCLUSIONS

This study suggests that an elevated plasma S100A12 level was closely associated with atherosclerosis. With aging elevated plasma S100A12 may show a powerful proatherogenic potential in patients undergoing PD.

A standardized randomized 6-month aerobic exercise-training down-regulated pro-inflammatory genes, but up-regulated anti-inflammatory, neuron survival and axon growth-related genes

There is considerable support for the view that aerobic exercise may confer cognitive benefits to mild cognitively impaired elderly persons. However, the biological mechanisms mediating these effects are not entirely clear. As a preliminary step towards informing this gap in knowledge, we enrolled older adults confirmed to have mild cognitive impairment (MCI) in a 6-month exercise program. Male and female subjects were randomized into a 6-month program of either aerobic or stretch (control) exercise. Data collected from the first 10 completers, aerobic exercise (n=5) or stretch (control) exercise (n=5), were used to determine intervention-induced changes in the global gene expression profiles of the aerobic and stretch groups. Using microarray, we identified genes with altered expression (relative to baseline values) in response to the 6-month exercise intervention. Genes whose expression were altered by at least two-fold, and met the p-value cutoff of 0.01 were inputted into the Ingenuity Pathway Knowledge Base Library to generate gene-interaction networks. After a 6-month aerobic exercise-training, genes promoting inflammation became down-regulated, whereas genes having anti-inflammatory properties and those modulating immune function or promoting neuron survival and axon growth, became up-regulated (all fold change≥±2.0, p<0.01). These changes were not observed in the stretch group. Importantly, the differences in the expression profiles correlated with significant improvement in maximal oxygen uptake (VO2max) in the aerobic program as opposed to the stretch group. We conclude that three distinct cellular pathways may collectively influence the training effects of aerobic exercise in MCI subjects. We plan to confirm these effects using rt-PCR and correlate such changes with the cognitive phenotype.

S100A9 induced inflammatory responses are mediated by distinct damage associated molecular patterns (DAMP) receptors in vitro and in vivo

Release of endogenous damage associated molecular patterns (DAMPs), including members of the S100 family, are associated with infection, cellular stress, tissue damage and cancer. The extracellular functions of this family of calcium binding proteins, particularly S100A8, S100A9 and S100A12, are being delineated. They appear to mediate their functions via receptor for advanced glycation endproducts (RAGE) or TLR4, but there remains considerable uncertainty over the relative physiological roles of these DAMPs and their pattern recognition receptors. In this study, we surveyed the capacity of S100 proteins to induce proinflammatory cytokines and cell migration, and the contribution RAGE and TLR4 to mediate these responses in vitro. Using adenoviral delivery of murine S100A9, we also examined the potential for S100A9 homodimers to trigger lung inflammation in vivo. S100A8, S100A9 and S100A12, but not the S100A8/A9 heterodimer, induced modest levels of TLR4-mediated cytokine production from human PBMC. In contrast, for most S100s including S100A9, RAGE blockade inhibited S100-mediated cell migration of THP1 cells and major leukocyte populations, whereas TLR4-blockade had no effect. Intranasal administration of murine S100A9 adenovirus induced a specific, time-dependent predominately macrophage infiltration that coincided with elevated S100A9 levels and proinflammatory cytokines in the BAL fluid. Inflammatory cytokines were markedly ablated in the TLR4-defective mice, but unexpectedly the loss of TLR4 signaling or RAGE-deficiency did not appreciably impact the S100A9-mediated lung pathology or the inflammatory cell infiltrate in the alveolar space. These data demonstrate that physiological levels of S100A9 homodimers can trigger an inflammatory response in vivo, and despite the capacity of RAGE and TLR4 blockade to inhibit responses in vitro, the response is predominately independent of both these receptors.

Treatment of Muckle-Wells syndrome: analysis of two IL-1-blocking regimens

Objectives

Muckle-Wells syndrome (MWS) is an autoinflammatory disease characterized by excessive interleukin-1 (IL-1) release, resulting in recurrent fevers, sensorineural hearing loss, and amyloidosis. IL-1 inhibition with anakinra, an IL-1 receptor antagonist, improves clinical symptoms and inflammatory markers. Subclinical disease activity is commonly observed. Canakinumab, a fully human IgG1 anti-IL-1β monoclonal antibody, can abolish excess IL-1β. The study aim was to analyze the efficacy and safety of these two anti-IL-1 therapies.

Methods

Two cohorts of patients with severe MWS and confirmed NLRP3 mutation were treated with anakinra and/or canakinumab. Clinical and laboratory features including ESR, CRP, SAA, and the neutrophil marker S100A12 were determined serially. Disease activity was captured by MWS disease activity scores (MWS-DAS). Remission was defined as MWS-DAS ≤5 plus normal CRP and SAA. Treatment efficacy and safety were analyzed.

Results

The study included 12 anakinra- and 14 canakinumab-treated patients; the median age was 33.5 years (3.0 years to 72.0 years); 57% were female patients. Both treatment regimens led to a significant reduction of clinical disease activity and inflammatory markers. At last follow-up, 75% of anakinra-treated and 93% of canakinumab-treated patients achieved remission. During follow-up, S100A12 levels mirrored recurrence of disease activity. Both treatment regimens had favorable safety profiles.

Conclusions

IL-1 blockade is an effective and safe treatment in MWS patients. MWS-DAS in combination with MWS inflammatory markers provides an excellent monitoring tool set. Canakinumab led to a sustained control of disease activity even after secondary failure of anakinra therapy. S100A12 may be a sensitive marker to detect subclinical disease activity.

A blood-based biomarker panel to detect acute stroke

BACKGROUND

The aim of this study was to develop an adjunctive, peripheral biomarker test to differentiate ischemic strokes, intracranial hemorrhages (ICHs), and stroke mimics in the acute setting.

METHODS

Serum samples were collected from 167 patients who presented with an acute neurologic deficit within 24 hours of symptom onset. Patients were adjudicated to ischemic stroke, ICH, and mimic pathology groups based on clinical and radiographic findings. Samples were tested for levels of 262 potential markers. A multivariate Cox proportional hazards regression model of 5 biomarkers was built by stepwise selection and validated by bootstrapping. Its discriminative capacity was quantified by C index and net reclassification improvement (NRI).

RESULTS

The final model consisted of eotaxin, epidermal growth factor receptor, S100A12, metalloproteinase inhibitor-4, and prolactin. It demonstrated a discriminative capacity for ischemic stroke versus mimic (C = .92), ischemic stroke and ICH versus mimic (C = .93), and ischemic stroke versus ICH (C = .82). The inclusion of biomarkers to a model consisting of age, race, and gender resulted in an NRI of 161% when detecting ischemic stroke versus mimic (P < .0001), an improvement of 171% when detecting ischemic strokes plus ICH versus mimic (P < .0001), and an improvement of 56% when detecting ischemic strokes versus ICH (P = .1419).

CONCLUSIONS

These results suggest that information obtained from a 5-biomarker panel may add valuable information in the early evaluation and management of patients with stroke-like symptoms.

Significant modifications of the salivary proteome potentially associated with complications of Down syndrome revealed by top-down proteomics

People with Down syndrome, a frequent genetic disorder in humans, have increased risk of health problems associated with this condition. One clinical feature of Down syndrome is the increased prevalence and severity of periodontal disease in comparison with the general population. Because saliva plays an important role in maintaining oral health, in the present study the salivary proteome of Down syndrome subjects was investigated to explore modifications with respect to healthy subjects. Whole saliva of 36 Down syndrome subjects, divided in the age groups 10-17 yr and 18-50 yr, was analyzed by a top-down proteomic approach, based on the high performance liquid chromatography-electrospray ionization-MS analysis of the intact proteins and peptides, and the qualitative and quantitative profiles were compared with sex- and age-matched control groups. The results showed the following interesting features: 1) as opposed to controls, in Down syndrome subjects the concentration of the major salivary proteins of gland origin did not increase with age; as a consequence concentration of acidic proline rich proteins and S cystatins were found significantly reduced in older Down syndrome subjects with respect to matched controls; 2) levels of the antimicrobial α-defensins 1 and 2 and histatins 3 and 5 were significantly increased in whole saliva of older Down syndrome subjects with respect to controls; 3) S100A7, S100A8, and S100A12 levels were significantly increased in whole saliva of Down syndrome subjects in comparison with controls. The increased level of S100A7 and S100A12 may be of particular interest as a biomarker of early onset Alzheimer's disease, which is frequently associated with Down syndrome.

Gene profiling of narrowband UVB-induced skin injury defines cellular and molecular innate immune responses

The acute response of human skin to UVB radiation has not been fully characterized. We sought to define the cutaneous response at 24 hours following narrowband UVB (NB-UVB, 312-nm peak), a therapeutically relevant source of UVB, using transcriptional profiling, immunohistochemistry, and immunofluorescence. There were 1,522 unique differentially regulated genes, including upregulated genes encoding antimicrobial peptides (AMPs) (S100A7, S100A12, human beta-defensin 2, and elafin), as well as neutrophil and monocyte/dendritic cell (DC) chemoattractants (IL-8, CXCL1, CCL20, CCL2). Ingenuity pathway analysis demonstrated activation of innate defense and early adaptive immune pathways. Immunohistochemistry confirmed increased epidermal staining for AMPs (S100A7, S100A12, human beta-defensin 2, and elafin). Inflammatory myeloid CD11c(+)BDCA1(-) DCs were increased in irradiated skin, which were immature as shown by minimal colocalization with DC-LAMP, and coexpressed inflammatory markers tumor necrosis factor (TNF) and TNF-related apoptosis-inducing ligand in irradiated skin. There were increased BDCA3(+) DCs, a cross-presenting DC subtype with immunosuppressive functions, and these cells have not been previously characterized as part of the response to UVB. These results show that the acute response of human skin to erythemogenic doses of NB-UVB includes activation of innate defense mechanisms, as well as early infiltration of multiple subtypes of inflammatory DCs, which could serve as a link between innate and adaptive immunity.

Expression of receptor for advanced glycation end products (RAGE) on the surface of circulating endothelial cells is upregulated in Kawasaki disease

INTRODUCTION

The aim of this study was to investigate the expression of receptor for advanced glycation end products (RAGE) on the surface of circulating endothelial cells (CECs) in patients with Kawasaki disease (KD).

METHODS

The positive rate of RAGE on the surface of CECs (CECs-RAGE/CECs) and the fluorescence intensity of RAGE on the surface of CECs (FI-RAGE-CECs) were evaluated in 89 patients with KD in the acute stage (A-KD), subacute stage (SA-KD), or convalescent stage (C-KD).

RESULTS

CECs-RAGE/CECs and the FI-RAGE-CECs increased significantly in patients with KD. The CECs-RAGE/CECs was significantly higher in C-KD patients with coronary artery lesions (CALs) than in those without CALs. The FI-RAGE-CECs level was significantly higher in SA-KD and C-KD patients with CALs than in A-KD patients. In SA-KD and C-KD patients, the CECs-RAGE/CECs and FI-RAGE-CECs levels decreased in intravenous immunoglobulin (IVIG)-respondent patients but increased progressively in IVIG-resistant patients and were significantly higher in IVIG-resistant patients than in IVIG-respondent patients.

DISCUSSION

The results suggest that the expression levels of RAGE on the surface of CECs are upregulated in KD patients, and that the upregulated expression levels of RAGE on the surface of CECs can be aggravated in SA-KD and C-KD patients with CALs, and also in IVIG-resistant SA-KD and C-KD patients. The RAGE expression on CECs is involved in the pathophysiology of KD.

EN-RAGE (extracellular newly identified receptor for advanced glycation end-products binding protein) and mortality of long-term hemodialysis patients: A prospective observational cohort study

OBJECTIVES

EN-RAGE is extracellular newly identified receptor for advanced glycation end-products binding protein playing a role in inflammation. The aim was to test the relationship of EN-RAGE to prognosis of long-term hemodialysis patients (HD).

DESIGN AND METHODS

This is a prospective observational cohort study in 261 HD patients followed up for five years. Laboratory parameters were measured at the beginning of the study.

RESULTS

EN-RAGE was slightly but unsignificantly increased in HD patients compared with healthy controls and correlated significantly with inflammatory markers. Univariate Cox analysis demonstrated EN-RAGE as a significant predictor for mortality due to infection (HR (95%CI): 1.305 (1.063-1.602), per standard deviation, p=0.01), but this significance disappeared in multivariate Cox analysis when CRP was included into the model.

CONCLUSIONS

Our study demonstrates EN-RAGE as an inflammatory biomarker. It is related to mortality of HD patients due to infection, but in our study, it did not provide additional information to CRP.

In vitro identification and verification of inflammatory biomarkers in swine

Currently there are no non-steroidal anti-inflammatory drugs (NSAIDs) approved for the control of inflammation in swine due to a lack of validated animal models and suitable biomarkers to assess drug efficacy. This study investigates the differential expression of genes altered in response to Escherichia coli lipopolysaccharide (LPS) induced inflammation which may serve as indicators of NSAID efficacy. Unstimulated whole blood from swine was mixed with tissue culture media, stimulated with LPS, and RNA extracted at the following time points 0h, 1h, 3h, 24h and 48h. Total RNA was extracted and analyzed using a commercial swine DNA microarray. The DNA microarray was utilized as a screen to determine potential biomarkers, focusing on the genes that exhibited the greatest degree of differential expression. A master list of 57 genes was formed based on the differential expression as a result of the stimulation. Following analysis, 12 genes whose expressions were significantly altered (8 up- and 4 down-regulated) were chosen for verification via quantitative RT-PCR (qRT-PCR). The qRT-PCR analysis confirmed the differential expression of 11 of the 12 genes chosen via the microarray analyses. Specifically, traditional genes such as SAA, G-CSF, and IL-10 were up-regulated, while CD4 was down-regulated; all of the genes were altered by 24h or 48h post-stimulation. We demonstrate here that expression of these 11 genes is altered as a direct result of LPS stimulation and consequently inflammation.

S100A12 on circulating endothelial cells surface in children with Kawasaki disease

The purpose of this study was to investigate the expression of S100A12 on the surface of circulating endothelial cells (CECs) in children with Kawasaki disease (KD) and the correlations between S100A12 and coronary artery lesions (CALs). The ratio of CECs to mononuclear cells (CECs/MNC), the positive rate of S100A12 on CECs surface (CECs-S100A12/CECs), and the fluorescence intensity of S100A12 on CECs surface (FI-S100A12-CECs) were evaluated respectively in 42 patients with acute stage (A-KD), subacute stage (SA-KD) and convalescent stage KD (C-KD). The CECs/MNC ratio increased significantly in patients with A-KD and SA-KD with CALs. The CECs-S100A12/CECs rate and FI-S100A12-CECs level were significantly higher in patients with KD than in the controls. The FI-S100A12-CECs level decreased to near half levels in patients with SA-KD and C-KD without CALs, but increased continuously in patients with SA-KD with CALs. The CECs/MNC ratio and FI-S100A12-CECs level in patients with SA-KD with CALs were significantly higher than in patients with SA-KD without CALs. The FI-S100A12-CECs level was significantly higher in patients with C-KD with CALs than in C-KD without CALs. The S100A12 expression on the CECs surface increased significantly in patients with KD and persisted for a longer time in patients with CALs, suggesting that the S100A12 expression on CECs may be involved in the development of CALs.

Inflammation-associated S100 proteins: new mechanisms that regulate function

This review focuses on new aspects of extracellular roles of the calgranulins. S100A8, S100A9 and S100A12 are constitutively expressed in neutrophils and induced in several cell types. The S100A8 and S100A9 genes are regulated by pro- and anti-inflammatory mediators and their functions may depend on cell type, mediators within a particular inflammatory milieu, receptors involved in their recognition and their post-translational modification. The S100A8 gene induction in macrophages is dependent on IL-10 and potentiated by immunosuppressive agents. S100A8 and S100A9 are oxidized by peroxide, hypochlorite and nitric oxide (NO). HOCl generates intra-chain sulfinamide bonds; stronger oxidation promotes cross-linked forms that are seen in human atheroma. S100A8 is >200-fold more sensitive to oxidative cross-linking than low-density lipoprotein and may reduce oxidative damage. S100A8 and S100A9 can be S-nitrosylated. S100A8-SNO suppresses mast cell activation and inflammation in the microcirculation and may act as an NO transporter to regulate vessel tone in inflammatory lesions. S100A12 activates mast cells and is a monocyte and mast cell chemoattractant; a G-protein-coupled mechanism may be involved. Structure-function studies are discussed in relation to conservation and divergence of functions in S100A8. S100A12 induces cytokines in mast cells, but not monocytes/macrophages. It forms complexes with Zn(2+) and, by chelating Zn(2+), S100A12 significantly inhibits MMPs. Zn(2+) in S100A12 complexes co-localize with MMP-9 in foam cells in atheroma. In summary, S100A12 has pro-inflammatory properties that are likely to be stable in an oxidative environment, because it lacks Cys and Met residues. Conversely, S100A8 and S100A9 oxidation and S-nitrosylation may have important protective mechanisms in inflammation.

ANTI-INFECTIVE PROTECTIVE PROPERTIES OF S100 CALGRANULINS

The calgranulins are a subgroup of proteins in the S100 family (calgranulin A, S100A8; calgranulin B, S100A9 and calgranulin C, S100A12) that provide protective anti-infective and anti-inflammatory functions for the mammalian host. In this review, we discuss the structure-function relationships whereby S100A8 and S100A9, and for comparison, S100A12, provide intra- and extracellular protection during the complex interplay between infection and inflammation and how the calgranulins are regulated to optimally protect the host. Ideally located to support epithelial barrier function, calprotectin, a complex of S100A8/S100A9, is expressed in squamous mucosal keratinocytes and innate immune cells present at mucosal surfaces. The calgranulins are also abundantly produced in neutrophils and monocytes, whereas expression is induced in epidermal keratinocytes, gastrointestinal epithelial cells and fibroblasts during inflammation. The calgranulins show species-specific expression and function. For example, S100A8 is chemotactic in rodents but not in humans. In humans, S100A12 appears to serve as a functional chemotactic homolog to murine S100A8. Transition metal-binding and oxidation sites within calgranulins are able to create structural changes that may orchestrate new protective functions or binding targets. The calgranulins thus appear to adopt a variety of roles to protect the host. In addition to serving as a leukocyte chemoattractant, protective functions include oxidant scavenging, antimicrobial activity, and chemokine-like activities. Each function may reflect the concentration of the calgranulin, post-transcriptional modifications, oligomeric forms, and the proximal intracellular or extracellular environments. Calprotectin and the calgranulins are remarkable as multifunctional proteins dedicated to protecting the intra- and extracellular environments during infection and inflammation.

C-reactive protein (CRP) up-regulates expression of receptor for advanced glycation end products (RAGE) and its inflammatory ligand EN-RAGE in THP-1 cells: inhibitory effects of atorvastatin

BACKGROUND

Receptor for advanced glycation end products (RAGE) may play an important role in inflammatory processes and endothelial activation. Extracellular newly identified RAGE binding protein (EN-RAGE), natural pro-inflammatory ligand for RAGE. The role of C-reactive protein (CRP) as a mediator in inflammation and atherosclerosis is the subject of recent investigations worldwide. In the present study, we investigated the effect of CRP on RAGE and EN-RAGE gene expression in THP-1 monocytic cell line. MAP kinases (ERK, p38 and JNK) were exploited as possible signaling pathways involved in the signal transduction by CRP. Further, atorvastatin was used as a therapeutic modality for modulation of these genes in the presence of CRP.

MATERIALS AND METHODS

Time and dose-dependent experiments were carried out in the presence of CRP. Specific MAPK pathways inhibitors were used to elucidate the signaling pathways involved. Effect of atorvastatin was also determined in the presence of CRP on the expression of these genes.

RESULTS

Time and dose-dependent experiments revealed that, treatment of THP-1 cells with 100 microg of CRP/ml/10(6) cells for 24 h, augmented the expression of RAGE and EN-RAGE genes by 2.5-3.5 folds and 3.5-4.5 folds respectively. CRP acted via FcgammaRII and utilized ERK, p38 and JNK pathways to transduce signals. Atorvastatin in a dose of 20 muM, was able to attenuate up-regulation of CRP-induced genes (p<0.01) and effects were both dose and time-dependent.

CONCLUSION

Our data strongly suggests that blockade of RAGE-EN-RAGE by statins at an early stage may prevent inflammation in atherosclerosis and counteract the harmful effects mediated by CRP.

Chemotactic activity of S100A7 (Psoriasin) is mediated by the receptor for advanced glycation end products and potentiates inflammation with highly homologous but functionally distinct S100A15

Human S100A7 (psoriasin) is overexpressed in inflammatory diseases. The recently discovered, co-evolved hS100A15 is almost identical in sequence and up-regulated with hS100A7 during cutaneous inflammation. The functional role of these closely related proteins for inflammation remains undefined. By generating specific Abs, we demonstrate that hS100A7 and hS100A15 proteins are differentially expressed by specific cell types in the skin. Although highly homologous, both proteins are chemoattractants with distinct chemotactic activity for leukocyte subsets. We define RAGE (receptor for advanced glycation end products) as the hS100A7 receptor, whereas hS100A15 functions through a Gi protein-coupled receptor. hS100A7-RAGE binding, signaling, and chemotaxis are zinc-dependent in vitro, reflecting the previously reported zinc-mediated changes in the hS100A7 dimer structure. When combined, hS100A7 and hS100A15 potentiate inflammation in vivo. Thus, proinflammatory synergism in disease may be driven by the diverse biology of these almost identical proteins that have just recently evolved. The identified S100A7 interaction with RAGE may provide a novel therapeutic target for inflammation.

Olopatadine suppresses the migration of THP-1 monocytes induced by S100A12 protein

Olopatadine hydrochloride (olopatadine) is an antiallergic drug with histamine H(1) receptor antagonistic activity. Recently, olopatadine has been shown to bind to S100A12 which is a member of the S100 family of calcium-binding proteins, and exerts multiple proinflammatory activities including chemotaxis for monocytes and neutrophils. In this study, we examined the possibility that the interaction of olopatadine with S100A12 inhibits the proinflammatory effects of S100A12. Pretreatment of olopatadine with S100A12 reduced migration of THP-1, a monocyte cell line, induced by S100A12 alone, but did not affect recombinant human regulated upon activation, normal T cell expressed and secreted (RANTES)-induced migration. Amlexanox, which also binds to S100A12, inhibited the THP-1 migration induced by S100A12. However, ketotifen, another histamine H(1) receptor antagonist, had little effect on the activity of S100A12. These results suggest that olopatadine has a new mechanism of action, that is, suppression of the function of S100A12, in addition to histamine H(1) receptor antagonistic activity.

S100A9 mediates neutrophil adhesion to fibronectin through activation of beta2 integrins

Neutrophil migration from the blood to inflammatory sites follows a cascade of events, in which adhesion to endothelial cells and extracellular matrix proteins is essential. S100A8, S100A9, and S100A12 are small abundant proteins found in human neutrophil cytosol and presumed to be involved in leukocyte migration. Here we investigated the S100 proteins' activities in neutrophil tissue migration by evaluating their effects on neutrophil adhesion to certain extracellular matrix proteins. S100A9 induced adhesion only to fibronectin and was the only S100 protein that stimulated neutrophil adhesion to this extracellular matrix protein. Experiments with blocking antibodies revealed that neither beta1 nor beta3 integrins were strongly involved in neutrophil adhesion to fibronectin, contrary to what the literature predicted. In contrast, neutrophil adhesion to fibronectin was completely inhibited by anti-beta2 integrins, suggesting that S100A9-induced specific activation of beta2 integrin is essential to neutrophil adhesion.

S100 proteins expressed in phagocytes: a novel group of damage-associated molecular pattern molecules

Damage-associated molecular pattern (DAMP) molecules have been introduced as important proinflammatory factors of innate immunity. One example known for many years to be expressed in cells of myeloid origin are phagocytic S100 proteins, which mediate inflammatory responses and recruit inflammatory cells to sites of tissue damage. An emerging concept of pattern recognition involves the multiligand receptor for advanced glycation end products (RAGE) and Toll-like receptors (TLRs) in sensing not only pathogen-associated molecular patterns (PAMPs) but also endogenous DAMPs, including S100 proteins. S100A8, S100A9, and S100A12 are found at high concentrations in inflamed tissue, where neutrophils and monocytes belong to the most abundant cell types. They exhibit proinflammatory effects in vitro at concentrations found at sites of inflammation in vivo. Although S100A12 binds to RAGE, at least part of the proinflammatory effects of the S100A8/S100A9 complex depend upon interaction with other receptors. Because of the divergent expression patterns, the absence of S100A12 in rodents, the different interaction partners described, and the specific intracellular and extracellular effects reported for these proteins, it is important to differentiate between distinct S100 proteins rather than subsuming them with the term "S100/calgranulins." Analyzing the molecular basis of the specific effects exhibited by these proteins in greater detail bears the potential to elucidate important mechanisms of innate immunity, to establish valid biomarkers of phagocytic inflammation, and eventually to reveal novel targets for innovative anti-inflammatory therapies.

The expression of RAGE and EN-RAGE in leprosy

BACKGROUND

Extracellular newly identified RAGE-binding protein (EN-RAGE) is a ligand of the receptor for advanced glycation endproducts (RAGE) and has been termed S100A12. The ligation of EN-RAGE with RAGE on the endothelium, mononuclear phagocytes and lymphocytes triggers cellular activation with the generation of the key proinflammatory mediators interleukin (IL)-1beta and tumour necrosis factor (TNF)-alpha.

OBJECTIVES

The aim of this study was to investigate the presence of RAGE and EN-RAGE, their spatial localization and their coexpression in leprosy lesions.

METHODS

Immunohistochemistry and confocal laser scanning microscopy were used to evaluate the expression of RAGE and EN-RAGE in leprosy. By enzyme-linked immunosorbent assay, RAGE and EN-RAGE were detected in the serum.

RESULTS

(1) In the multibacillary (MB) and paucibacillary (PB) groups, the level of RAGE production was significantly higher than in patients with atypical mycobacterial infection or sarcoidosis (P < 0.01). In the MB group, the production of RAGE was higher than in the PB group (P < 0.01), and it was higher in patients without the lepra reaction than in patients with the lepra reaction (P < 0.05). (2) In MB, PB and atypical mycobacterial infection, the level of EN-RAGE production was significantly higher than in sarcoidosis (P < 0.01). (3) In the confocal laser scanning microscopic examination, the RAGE and EN-RAGE proteins were detected in lepromatous leprosy. These proteins are spatially colocalized along the cell surface, which is in agreement with their receptor-ligand interaction. (4) A comparable amount of EN-RAGE was detected in the serum of the MB and PB groups. Patients with the reaction showed a higher level of EN-RAGE than patients without the reaction in leprosy.

CONCLUSIONS

Our data suggest that in leprosy, RAGE and EN-RAGE may be involved in the proinflammatory process rather than the antimycobacterial activity, especially during the lepra reaction. The blockade of the interaction of RAGE and EN-RAGE at the early stage of the inflammatory process may minimize the inflammatory response and consequent tissue damage or the sequelae of leprosy.

Total Chemical Synthesis of Human Psoriasin by Native Chemical Ligation†

Human psoriasin (S100A7), a member of the S100 family of calcium-binding proteins, is richly expressed in keratinocytes of patients suffering from psoriasis. To date, the exact physiological function of psoriasin abundant in many human cell types remains unclear. A recent report by Schröder and colleagues suggests that psoriasin, purified from human stratum corneum extracts, selectively kills Escherichia coli by sequestering Zn(2+) ions essential for bacterial growth, indicative of an important role in innate immune defense against microbial infection. We chemically synthesized the N-terminally acetylated psoriasin of 100 amino acid residues using solid phase peptide synthesis in combination with native chemical ligation. More than 140 mg of highly pure and correctly folded synthetic psoriasin was obtained from a single synthesis on a 0.25 mmol scale. Analysis of synthetic psoriasin by size exclusion chromatography showed that the protein forms a homodimer in solution. Circular dichroism analysis indicated that the alpha-helicity of psoriasin increases by more than 20% in the presence of CaCl(2) or ZnCl(2), suggesting a metal ion binding induced conformational change. Circular dichroism based titration further established that the synthetic protein binds two Ca(2+) and two Zn(2+) ions per dimer, in agreement with the published structural findings. Importantly, the ability of the synthetic protein to kill E. coli and the inhibition of the killing by ZnCl(2) is comparable to that of psoriasin isolated from its natural source. The robust synthetic access to large quantities of human psoriasin should facilitate studies of its biological functions as well as its mode of action.

Inflammatory S100A9 and S100A12 proteins in Alzheimer's disease

Inflammation, insoluble protein deposition and neuronal cell loss are important features of the Alzheimer's disease (AD) brain. S100B is associated with the neuropathological hallmarks of AD where it is thought to play a role in neuritic pathology. S100A8, S100A9 and S100A12 comprise a new group of inflammation-associated proteins that are constitutively expressed by neutrophils and inducible in numerous inflammatory cells. We investigated expression of S100B, S100A8, S100A9 and S100A12 in brain samples from sporadic and familial (PS-1) AD cases and controls using immunohistochemistry and Western blot analysis. S100B, S100A9 and S100A12, but not S100A8, were consistently associated with the neuropathological hallmarks of AD. Western blot analysis confirmed significant increases in soluble S100A9 in PS-1 AD compared to controls. S100A9 complexes that were resistant to reduction were also evident in brain extracts. A reactive component of a size consistent with hexameric S100A12 was seen in all cases. This study indicates a potential role for pro-inflammatory S100A9 and S100A12 in pathogenesis caused by inflammation and protein complex formation in AD.