ADAM10 Plasma and CSF Levels Are Increased in Mild Alzheimer's Disease.

ADAM10 is the main α-secretase that participates in the non-amyloidogenic cleavage of amyloid precursor protein (APP) in neurons, inhibiting the production of ß-amyloid peptide (Aß) in Alzheimer's disease (AD). Strong recent evidence indicates the importance of the localization of ADAM10 for its activity as a protease. In this study, we investigated ADAM10 activity in plasma and CSF samples of patients with amnestic mild cognitive impairment (aMCI) and mild AD compared with cognitively healthy controls. Our results indicated that plasma levels of soluble ADAM10 were significantly increased in the mild AD group, and that in these samples the protease was inactive, as determined by activity assays. The same results were observed in CSF samples, indicating that the increased plasma ADAM10 levels reflect the levels found in the central nervous system. In SH-SY5Y neuroblastoma cells, ADAM10 achieves its major protease activity in the fraction obtained from plasma membrane lysis, where the mature form of the enzyme is detected, confirming the importance of ADAM10 localization for its activity. Taken together, our results demonstrate the potential of plasma ADAM10 to act as a biomarker for AD, highlighting its advantages as a less invasive, easier, faster, and lower-cost processing procedure, compared to existing biomarkers.

Soluble Receptor for Advanced Glycation End-products (sRAGE) and Colorectal Cancer Risk: A Case-Control Study Nested within a European Prospective Cohort.

BACKGROUND: Overexpression of the receptor for advanced glycation end-product (RAGE) has been associated with chronic inflammation, which in turn has been associated with increased colorectal cancer risk. Soluble RAGE (sRAGE) competes with RAGE to bind its ligands, thus potentially preventing RAGE-induced inflammation. METHODS: To investigate whether sRAGE and related genetic variants are associated with colorectal cancer risk, we conducted a nested case-control study in the European Prospective Investigation into Cancer and Nutrition (EPIC). Plasma sRAGE concentrations were measured by ELISA in 1,361 colorectal cancer matched case-control sets. Twenty-four SNPs encoded in the genes associated with sRAGE concentrations were available for 1,985 colorectal cancer cases and 2,220 controls. Multivariable adjusted ORs and 95% confidence intervals (CIs) were computed using conditional and unconditional logistic regression for colorectal cancer risk and circulating sRAGE and SNPs, respectively. RESULTS: Higher sRAGE concentrations were inversely associated with colorectal cancer (ORQ5vs.Q1, 0.77; 95% CI, 0.59-1.00). Sex-specific analyses revealed that the observed inverse risk association was restricted to men (ORQ5vs.Q1, 0.63; 95% CI, 0.42-0.94), whereas no association was observed in women (ORQ5vs.Q1, 1.00; 95% CI, 0.68-1.48; P heterogeneity for sex = 0.006). Participants carrying minor allele of rs653765 (promoter region of ADAM10) had lower colorectal cancer risk (C vs. T, OR, 0.90; 95% CI, 0.82-0.99). CONCLUSIONS: Prediagnostic sRAGE concentrations were inversely associated with colorectal cancer risk in men, but not in women. An SNP located within ADAM10 gene, pertaining to RAGE shedding, was associated with colorectal cancer risk. IMPACT: Further studies are needed to confirm our observed sex difference in the association and better explore the potential involvement of genetic variants of sRAGE in colorectal cancer development.

Proteomic Analysis of Blood Exosomes from Healthy Females and Breast Cancer Patients Reveals an Association between Different Exosomal Bioactivity on Non-tumorigenic Epithelial Cell and Breast Cancer Cell Migration in Vitro.

Exosomes are important intercellular communication vehicles, secreted into body fluids by multiple cell types, including tumor cells. They contribute to the metastatic progression of tumor cells through paracrine signalling. It has been recently discovered that blood circulating exosomes contain distinguishable fractions of free and cell-surface-associated vesicles. We evaluated the influence of protein cargoes from exosomes from plasma, and exosomes from the total blood of healthy females (HFs) and breast cancer patients (BCPs), on cell motility. We conducted a mass spectrometric analysis of exosomal contents isolated from samples using ultrafiltration and ultracentrifugation approaches and verified their nature using transmission electron microscopy, nanoparticle tracking analysis and flow cytometry. We observed that malignant neoplasm-associated proteins in exosomes from BCP total blood were detected more often than in plasma (66% vs. 59%). FunRich analysis to assess Gene Ontology (GO) enrichment revealed that proteins with catalytic activities, transporter functions and protein metabolism activities were increased in exosomes from BCP blood. Finally, GO analysis revealed that proteomic profiles of exosomes from HF total blood were enriched with proteins inhibiting cell migration and invasion, which explains the low stimulating activity of exosomes from HF total blood on SKBR-3 cancer cell migration velocity. This allows exosomes to act as intermediaries providing intercellular communications through horizontal transfer of RNA and functionally active proteins, potentially affecting the development of both primary neoplasms and distant metastases.

Abnormal platelet amyloid-ß precursor protein metabolism in SAMP8 mice: Evidence for peripheral marker in Alzheimer's disease.

Senescence-accelerated mouse strains have proved to be an accelerated-aging model, which mimics numerous features with Alzheimer's disease (AD). Three, six, and nine-month senescence-accelerated resistant 1 and senescence-accelerated prone 8 (SAMP8) mice were used in the current study, to unravel potential mechanisms for dementia and explore new diagnostic approaches for AD. The amyloid-ß (Aß40) and Aß42 levels were elevated in hippocampi and platelets from SAMP8, along with a reduced α-secretase expression and an enhanced ß-secretase expression extent with age, compared to control mice. Furthermore, hippocampal Aß40 and Aß42 of SAMP8 were positively correlated with platelet of these mice with aging progression. In addition, ß-γ-secretase-modulated proteolytic proceeding of amyloid precursor protein in platelet might work through the PI3K/Akt/GSK3ß pathway. These results indicate that platelet could be a potential early marker in the periphery to study the age-correlative aggregation of the amyloid-ß peptide in patients with AD, while still requiring the considerable study.

First-in-human study of LY3039478, an oral Notch signaling inhibitor in advanced or metastatic cancer.

Background: Deregulated Notch signaling due to mutation or overexpression of ligands and/or receptors is implicated in various human malignancies. γ-Secretase inhibitors inhibit Notch signaling by preventing cleavage of transmembrane domain of Notch protein. LY3039478 is a novel, potent Notch inhibitor decreases Notch signaling and its downstream biologic effects. In this first-in-human study, we report the safety, pharmacokinetic (PK) profile, pharmacodynamic effects, and antitumor activity of LY3039478 in patients with advanced or metastatic cancer. Methods: This phase I, open-label, multicenter, nonrandomized, and dose-escalation phase study determined and confirmed the recommended phase II dose of LY3039478 (oral dose: 2.5-100 mg, thrice weekly (TIW) on a 28-day cycle). The primary objectives are to determine (part A) and confirm (part B) a recommended phase II dose that may be safely administered to patients with advanced or metastatic cancer, and secondary objectives include evaluation of safety, tolerability, PK parameters, and preliminary antitumor activity of LY3039478. Results: A total of 110 patients were treated with LY3039478 monotherapy between 31 October 2012 and 15 July 2016. Dose-limiting toxicities were thrombocytopenia, colitis, and nausea. Most adverse events were gastrointestinal. The recommended phase II dose was 50 mg TIW, because of its better tolerability compared with 75 mg. The PKs of LY3039478 appeared dose proportional. Pharmacodynamic data indicate an ∼80% inhibition of plasma Aß, and >50% inhibition of Notch-regulated genes hairy and enhancer of split-1, cyclin D1, and Notch-regulated ankyrin repeat at 45-100-mg dose. Clinical activity (tumor necrosis, metabolic response, or tumor shrinkage) was observed in patients with breast cancer, leiomyosarcoma, and adenoid cystic carcinoma. Conclusion: Potent inhibition of Notch signaling by LY3039478 was well tolerated at doses associated with target engagement, and demonstrated evidence of clinical activity in heavily pretreated patients. Further investigation with LY3039478 as monotherapy and in combination with targeted agent or chemotherapy is ongoing. Clinicaltrials.gov ID: NCT01695005.

Identification of disulfiram as a secretase-modulating compound with beneficial effects on Alzheimer's disease hallmarks.

ADAM10 is a metalloproteinase acting on the amyloid precursor protein (APP) as an alpha-secretase in neurons. Its enzymatic activity results in secretion of a neuroprotective APP cleavage product (sAPP-alpha) and prevents formation of the amyloidogenic A-beta peptides, major hallmarks of Alzheimer's disease (AD). Elevated ADAM10 levels appeared to contribute to attenuation of A-beta-plaque formation and learning and memory deficits in AD mouse models. Therefore, it has been assumed that ADAM10 might represent a valuable target in AD therapy. Here we screened a FDA-approved drug library and identified disulfiram as a novel ADAM10 gene expression enhancer. Disulfiram increased ADAM10 production as well as sAPP-alpha in SH-SY5Y human neuronal cells and additionally prevented A-beta aggregation in an in vitro assay in a dose-dependent fashion. In addition, acute disulfiram treatment of Alzheimer model mice induced ADAM10 expression in peripheral blood cells, reduced plaque-burden in the dentate gyrus and ameliorated behavioral deficits. Alcohol-dependent patients are subjected to disulfiram-treatment to discourage alcohol-consumption. In such patients, enhancement of ADAM10 by disulfiram-treatment was demonstrated in peripheral blood cells. Our data suggest that disulfiram could be repurposed as an ADAM10 enhancer and AD therapeutic. However, efficacy and safety has to be analyzed in Alzheimer patients in the future.

Soluble Leptin Receptor Predicts Insulin Sensitivity and Correlates With Upregulation of Metabolic Pathways in Men.

Context: Plasma soluble leptin receptor (sOb-R) seems protective of gestational and type 2 diabetes in observational studies, but the mechanisms are unknown. sOb-R is formed by ectodomain shedding of membrane-bound leptin receptors (Ob-Rs), but its associations with messenger RNA (mRNA) expression are scarcely explored. Objective: To explore associations between plasma levels of sOb-R and (1) insulin sensitivity, (2) mRNA pathways in adipose tissue and skeletal muscle, and (3) mRNA of candidate genes for sOb-R generation in adipose tissue and skeletal muscle. Design and Participants: The MyoGlu study included 26 sedentary, middle-aged men who underwent a 12-week intensive exercise intervention. We measured plasma sOb-R with enzyme-linked immunosorbent assay, insulin sensitivity with a hyperinsulinemic euglycemic clamp, and mRNA in skeletal muscle and adipose tissue with high-throughput sequencing. Results: Baseline plasma sOb-R was strongly associated with baseline glucose infusion rate (GIR) [ß (95% confidence interval), 1.19 (0.57 to 1.82) mg/kg/min, P = 0.0006] and GIR improvement after the exercise intervention [0.58 (0.03 to 1.12) mg/kg/min, P = 0.039], also independently of covariates, including plasma leptin. In pathway analyses, high plasma sOb-R correlated with upregulation of metabolic pathways and downregulation of inflammatory pathways in both adipose tissue and skeletal muscle. In skeletal muscle, mRNA of LEPROT and LEPROTL1 (involved in Ob-R cell surface expression) and ADAM10 and ADAM17 (involved sOb-R-shedding) increased after the exercise intervention. Conclusions: Higher plasma sOb-R was associated with improved GIR, upregulation of metabolic pathways, and downregulation of inflammatory pathways, which may be possible mechanisms for the seemingly protective effect of plasma sOb-R on subsequent risk of gestational and type 2 diabetes found in observational studies.

Serum levels of ADAM10, ADAM12, ADAM17 AND ADAM28 in colorectal cancer patients.

Colorectal cancer is the third most common cancer in the world. Our study analyzed the potential significance of serum levels of selected adamalysines (ADAM10, ADAM12, ADAM17, ADAM28) in colorectal cancer patients. The study was performed on a group of 85 colorectal cancer patients (48 men, 37 women). Serum protein concentrations were measured by ELISA. The ADAMs serum level changes were analyzed according to selected clinical parameters (BMI, sex, age, clinical stage of disease). The following ranges of concentration of analyzed proteins were obtained: ADAM10 min=1.7, max=321.8 [ng/ml]; ADAM12 min=0.6, max=26.7 [ng/ml]; ADAM17 min=0.4, max=9.8 [ng/ml]; ADAM28 min=17.1, max=1545.8 [ng/ml]. In addition, it was stated that there is a relationship between the serum level of ADAM28 and the degree of the clinical stage (p less than 0.04). The obtained results could be the starting point for further research into the role of adamalysines in the development of colorectal cancer, as well as the potential predictive and prognostic value of these proteins.

Pharmacogenomics study on cadherin 2 network with regard to HIV infection and methadone treatment outcome.

Heroin dependent patients have a high incidence of HIV infection. In contrast to the gene expression method, we developed a systemic correlation analysis method built upon the results of pharmacogenomics study in a methadone maintenance treatment (MMT) cohort consisting of 344 Taiwanese heroin dependent patients. We identified genetic variants and their encoding proteins that may be involved with HIV infection and MMT treatment outcome. Cadherin 2 (CDH2) genetic determinants were identified through the genome-wide pharmacogenomic study. We found significant correlations among HIV infection status, plasma levels of CDH2, cytokine IL-7, ADAM10, and the treatment responses to methadone. Two single nucleotide polymorphisms located within CDH2 gene showed associations with blood pressure and plasma CDH2 concentration. Plasma concentration of CDH2 showed correlations with the level of cytokine IL-7, status of HIV infection, and urine morphine test result. Plasma level of IL-7 was correlated with corrected QT interval (QTc) and gooseflesh skin withdrawal symptom score, while level of ADAM10 was correlated with plasma concentrations of vitamin D metabolite, nicotine metabolite, and R-methadone. The results suggest a novel network involving HIV infection and methadone treatment outcome.

[Molecular markers of Alzheimer disease early diagnostic: investigation perspectives of peripheral tissues.]

Alzheimer's disease (AD) is a progressive neurodegenerative disorder of elderly and old age people. For intravital diagnosis of the expression of signaling molecules - AD markers, cerebrospinal fluid (CSF) and peripheral tissues are used: lymphocytes and blood platelets, buccal and olfactory epithelium, skin fibroblasts. There are several changes in the production of hyper phosphorylated form of τ-protein, BACE1 and peptide Аß42 in CSF in case of AD, but CSF taking may have a number of side effects. Less traumatic taking of sampling tissues for the diagnosis of AD is in use of epithelium biopsy and blood portion. An increase in the expression of the hyper phosphorylated form of τ-protein is shown in blood lymphocytes of AD patients. An increase in the content of high molecular weight forms of phosphorylated t-protein and amyloid precursor protein-APP was also revealed in blood platelets of AD patients. Changes in the amount of 2 miRNA families - miR-132 family and miR-134 family were revealed in blood cells 1-5 years before the manifestation of clinical signs of AD. An increase in the concentration of bound calcium, synthesis of peptides Aß40 and Aß42, τ protein was observed in AD skin fibroblasts. In the olfactory and buccal epithelium an increase in the expression of hyper phosphorylated form of τ-protein and Aß peptide was detected in patients with AD. Verification of AD markers in peripheral tissues for biopsy have the important significant for life diagnostics, prevention and and target AD treatment.

Dual Signal Amplification Electrochemical Biosensor for Monitoring the Activity and Inhibition of the Alzheimer's Related Protease ß-Secretase.

The protease BACE1 (the ß-site amyloid precursor protein cleaving enzyme 1) catalyzes the first step in the synthesis of ß-amyloids (Aß), peptides that accumulate in the brain in Alzheimer's disease (AD). Measurement of BACE1 activity is important for the development of BACE1 inhibitors to slow or stop AD. To measure BACE1 cleavage of the electrode-immobilized substrate peptide, we developed a redox-generating hydroxyapatite (HAP) probe which generates electrochemical current by reaction of the nanoparticle with molybdate (MoO42-). The probe combines alkaline phosphatase (ALP) for dual signal amplification and Aß antibody to bind the probe to the immobilized peptide substrate on the surface of the electrode. We measured the activity of BACE1 at concentrations ranging from 0.25 to 100 U/mL. The use of the dual-signal HAP-ALP probe increased the signal by an order of magnitude compared to HAP-only probe, enabling detection limits as low as 0.1 U/mL. To measure the inhibition of BACE1 activity, the BACE1 inhibitor OM99-2 was added to 25 U/mL of BACE1 in concentrations ranging from 5 to 150 nM. The observed detection limit of inhibition is 10 nM of OM99-2. These results demonstrate the capabilities of this novel biosensor to measure BACE1 activity and inhibitors of BACE1 activity. To the best of our knowledge this is the first report that reaction of HAP nanoparticles with molybdate can generate electrochemical current. This dual signal amplification strategy can be extended to other electrochemical assays and adapted for wide applications.

Association of CD30 transcripts with Th1 responses and proinflammatory cytokines in patients with end-stage renal disease.

High serum sCD30 levels are associated with inflammatory disorders and poor outcome in renal transplantation. The contribution to these phenomena of transcripts and proteins related to CD30-activation and -cleavage is unknown. We assessed in peripheral blood of end-stage renal disease patients (ESRDP) transcripts of CD30-activation proteins CD30 and CD30L, CD30-cleavage proteins ADAM10 and ADAM17, and Th1- and Th2-type immunity-related factors t-bet and GATA3. Additionally, we evaluated the same transcripts and release of sCD30 and 32 cytokines after allogeneic and polyclonal T-cell activation. In peripheral blood, ESRDP showed increased levels of t-bet and GATA3 transcripts compared to healthy controls (HC) (both P<0.01) whereas levels of CD30, CD30L, ADAM10 and ADAM17 transcripts were similar. Polyclonal and allogeneic stimulation induced higher levels of CD30 transcripts in ESRDP than in HC (both P<0.001). Principal component analysis (PCA) in allogeneic cultures of ESRDP identified two correlation clusters, one consisting of sCD30, the Th-1 cytokine IFN-γ, MIP-1α, RANTES, sIL-2Rα, MIP-1ß, TNF-ß, MDC, GM-CSF and IL-5, and another one consisting of CD30 and t-bet transcripts, IL-13 and proinflammatory proteins IP-10, IL-8, IL-1Rα and MCP-1. Reflecting an activated immune state, ESRDP exhibited after allostimulation upregulation of CD30 transcripts in T cells, which was associated with Th1 and proinflammatory responses.

Plasma soluble Tim-3 emerges as an inhibitor in sepsis: sepsis contrary to membrane Tim-3 on monocytes.

Immune dysfunction is the main characteristic of sepsis. T cell Ig and mucin domain protein 3 (Tim-3) on the monocytes has been reported to promote immune homeostasis during sepsis, but the influences of plasm soluble Tim-3 (sTim-3) on the immune system during sepsis remain unknown. Here, 100 patients with different severities of sepsis (40 sepsis, 42 severe sepsis, and 18 septic shock) were enrolled in this study. The Tim-3 and human leukocyte antigen-DR (HLA-DR) on the circulating monocytes were detected using flow cytometry. Plasma sTim-3 was detected by enzyme-linked immunosorbent assay. Inflammatory factors and two kinds of A disintegrin and metalloprotease (ADAM) - ADAM10 and ADAM17 were assessed. The Tim-3 and HLA-DR on the monocytes decreased with increasing sepsis severity. The sTim-3 was reduced in the sepsis and severe sepsis patients but was elevated in the septic shock patients who exhibited significant immunosuppression as predicted by HLA-DR. sTim-3 levels were negatively correlated with IL-12 and TNF-α. ADAM10 and ADAM17, sheddases of Tim-3, exhibited trends toward elevations in the septic shock group. In conclusion, sTim-3 was involved in the development of sepsis. The homeostasis-promoting role of the Tim-3 on the monocytes was disrupted, while the inhibitory role of sTim-3 emerged during sepsis-induced immunosuppression.

Serum Level of Soluble Receptor for Advanced Glycation End Products Is Associated with A Disintegrin And Metalloproteinase 10 in Type 1 Diabetes.

BACKGROUND: The receptor for advanced glycation end products (RAGE) is involved in the pathogenesis of diabetic complications, and soluble forms of the receptor (sRAGE) can counteract the detrimental action of the full-length receptor by acting as decoy. Soluble RAGE is produced by alternative splicing [endogenous secretory RAGE (esRAGE)] and/or by proteolytic cleavage of the membrane-bound receptor. We have investigated the role of A Disintegrin And Metalloproteinase 10 (ADAM10) in the ectodomain shedding of RAGE. METHODS: Constitutive and insulin-induced shedding of RAGE in THP-1 macrophages by ADAM10 was evaluated using an ADAM10-specific metalloproteinase inhibitor. Serum ADAM10 level was measured in type 1 diabetes and control subjects, and the association with serum soluble RAGE was determined. Serum total sRAGE and esRAGE were assayed by ELISA and the difference between total sRAGE and esRAGE gave an estimated measure of soluble RAGE formed by cleavage (cRAGE). RESULTS: RAGE shedding (constitutive and insulin-induced) was significantly reduced after inhibition of ADAM10 in macrophages, and insulin stimulated ADAM10 expression and activity. Diabetic subjects have higher serum total sRAGE and esRAGE (p<0.01) than controls, and serum ADAM10 was also increased (p<0.01). Serum ADAM10 correlated with serum cRAGE in type 1 diabetes (r = 0.40, p<0.01) and in controls (r = 0.31. p<0.01) but no correlations were seen with esRAGE. The association remained significant after adjusting for age, gender, BMI, smoking status and HbA1c. CONCLUSION: Our data suggested that ADAM10 contributed to the shedding of RAGE. Serum ADAM10 level was increased in type 1 diabetes and was a significant determinant of circulating cRAGE.

A disintegrin and metalloprotease-10 is correlated with disease activity and mediates monocyte migration and adhesion in rheumatoid arthritis.

A disintegrin and metalloproteases (ADAMs) are a family of proteins that have been reported to be involved in several inflammatory conditions. We examined the secretion of ADAM-10 in biological fluids from patients with rheumatoid arthritis (RA) and the role it plays in monocyte migration. ADAM-10 levels were measured using enzyme-linked immunosorbent assays and immunofluorescence. To examine the role of ADAM-10 in RA synovial fluids (SFs), we studied THP-1 (human acute monocyte leukemia cell line) and monocyte chemotaxis. To determine whether ADAM-10 plays a role in cell proliferation in the RA synovium, we assayed the proliferation of ADAM-10 small interfering RNA (siRNA)-transfected RA fibroblast-like synoviocytes (FLSs). The ADAM-10 level in RA serum was significantly higher than that in normal serum and was correlated with a disease activity score of 28. ADAM-10-depleted RA SFs showed a decrease in THP-1 and monocyte migratory activity compared with that of sham-depleted controls. ADAM-10 siRNA inhibited monocyte adhesion to RA FLSs. Finally, blocking ADAM-10 secretion in RA FLSs resulted in decreased production of fractalkine/CX3CL1 and vascular endothelial cell growth factor. These data indicate that ADAM-10 plays a role in monocyte migration in RA and suggest that targeting ADAM-10 may provide a method of decreasing inflammation and potentially treating other inflammatory diseases.

A new sandwich immunoassay for detection of the α-secretase cleaved, soluble amyloid-ß protein precursor in cerebrospinal fluid and serum.

Alzheimer's disease (AD) is the most common neurodegenerative disorder. Frequently used diagnostic biomarkers are amyloid-ß42 (Aß42), tau, and phospho-tau, which are measured in cerebrospinal fluid (CSF), and allow a reasonable, but not full, separation of AD patients and controls. Besides Aß42, additional proteolytic cleavage products of the amyloid-ß protein precursor (AßPP) have been investigated as potential biomarkers. This includes the α-secretase cleaved soluble AßPP ectodomain (sAßPPα). However, some studies found a reduction of sAßPPα, whereas other studies reported an increase of sAßPPα in the CSF of AD patients. The divergent findings may result from the detection of sAßPPα with antibodies, such as 6E10, which do not exclusively detect sAßPPα, but also the alternative ß-secretase cleavage product sAßPPß'. Here, we used the sAßPPα-specific antibody 14D6 and developed an ELISA-like sandwich immunoassay. The assay specifically detected sAßPPα in cell culture supernatants, in human CSF and even in serum, which is more readily accessible than CSF. The assay was used to analyze sAßPPα levels in CSF and serum of AD patients and controls. The assay detected a mild, but significant increase in sAßPPα in the CSF of AD patients compared to non-demented controls, while a mild reduction was observed in serum. The 14D6 assay in CSF allowed a better separation of AD patients from controls compared to the 6E10 antibody. Taken together, the new assay is widely applicable for specific sAßPPα measurement in culture media, CSF, and serum.

HIV Nef, paxillin, and Pak1/2 regulate activation and secretion of TACE/ADAM10 proteases.

The HIV Nef protein recruits the polycomb protein Eed and mimics an integrin receptor signal for reasons that are not entirely clear. Here we demonstrate that Nef and Eed complex with the integrin effector paxillin to recruit and activate TNFα converting enzyme (TACE alias ADAM 17) and its close relative ADAM10. The activated proteases cleaved proTNFα and were shuttled into extracellular vesicles (EVs). Peripheral blood mononuclear cells that ingested these EVs released TNFα. Analyzing the mechanism, we found that Pak2, an established host cell effector of Nef, phosphorylated paxillin on Ser272/274 to induce TACE-paxillin association and shuttling into EVs via lipid rafts. Conversely, Pak1 phosphorylated paxillin on Ser258, which inhibited TACE association and lipid raft transfer. Interestingly, melanoma cells used an identical mechanism to shuttle predominantly ADAM10 into EVs. We conclude that HIV-1 and cancer cells exploit a paxillin/integrin-controlled mechanism to release TACE/ADAM10-containing vesicles, ensuring better proliferation/growth conditions in their microenvironment.

IL-6 plays an essential role in neutrophilia under inflammation.

In the present study, we explored the involvement of interleukin-6 (IL-6) in neutrophilia under inflammatory conditions. The neutrophil count in the peripheral blood was high in arthritic monkeys, and anti-IL-6 receptor antibody reduced neutrophil counts to normal levels. IL-6 injection into normal monkeys significantly increased neutrophil counts in the blood 3h after injection. The expression of cluster of differentiation (CD) 162 on circulating neutrophils was reduced by IL-6 injection. IL-6 treatment in vitro did not affect CD162 expression on neutrophils from human blood. In IL-6-treated monkeys, IL-8 and granulocyte-macrophage colony-stimulating factor (GM-CSF) levels in plasma were clearly elevated. IL-8 and GM-CSF treatment in vitro reduced cell-surface CD162 expression on human neutrophils, and moreover, increased soluble CD162 expression in the cell supernatant. The addition of IL-6 into human whole peripheral blood induced IL-8 production and reduced CD162 expression on neutrophils. Furthermore, IL-8 and GM-CSF augmented mRNA expression of a disintegrin and metalloprotease like domain 10 (ADAM10) in neutrophils. Knock-down of ADAM10 by siRNA in neutrophil-like HL-60 cells partially reversed the expression of CD162 reduced by GM-CSF and IL-8 on HL-60 cells. In conclusion, IL-6 induced neutrophilia and reduced CD162 expression on neutrophils in inflammation.

S100A7, a novel Alzheimer's disease biomarker with non-amyloidogenic alpha-secretase activity acts via selective promotion of ADAM-10.

Alzheimer's disease (AD) is the most common cause of dementia among older people. At present, there is no cure for the disease and as of now there are no early diagnostic tests for AD. There is an urgency to develop a novel promising biomarker for early diagnosis of AD. Using surface-enhanced laser desorption ionization-mass spectrometry SELDI-(MS) proteomic technology, we identified and purified a novel 11.7-kDa metal- binding protein biomarker whose content is increased in the cerebrospinal fluid (CSF) and in the brain of AD dementia subjects as a function of clinical dementia. Following purification and protein-sequence analysis, we identified and classified this biomarker as S100A7, a protein known to be involved in immune responses. Using an adenoviral-S100A7 expression system, we continued to examine the potential role of S100A7 in AD amyloid neuropathology in in vitro model of AD. We found that the expression of exogenous S100A7 in primary cortico-hippocampal neuron cultures derived from Tg2576 transgenic embryos inhibits the generation of beta-amyloid (Abeta)(1-42) and Abeta(1-40) peptides, coincidental with a selective promotion of "non- amyloidogenic" alpha-secretase activity via promotion of ADAM (a disintegrin and metalloproteinase)-10. Finally, a selective expression of human S100A7 in the brain of transgenic mice results in significant promotion of alpha-secretase activity. Our study for the first time suggests that S100A7 may be a novel biomarker of AD dementia and supports the hypothesis that promotion of S100A7 expression in the brain may selectively promote alpha-secretase activity in the brain of AD precluding the generation of amyloidogenic peptides. If in the future we find that S1000A7 protein content in CSF is sensitive to drug intervention experimentally and eventually in the clinical setting, S100A7 might be developed as novel surrogate index (biomarker) of therapeutic efficacy in the characterization of novel drug agents for the treatment of AD.