Disruption of the productive encounter complex results in dysregulation of DIAPH1 activity.

The diaphanous-related formin, Diaphanous 1 (DIAPH1), is required for the assembly of Filamentous (F)-actin structures. DIAPH1 is an intracellular effector of the receptor for advanced glycation end products (RAGE) and contributes to RAGE signaling and effects such as increased cell migration upon RAGE stimulation. Mutations in DIAPH1, including those in the basic "RRKR" motif of its autoregulatory domain, diaphanous autoinhibitory domain (DAD), are implicated in hearing loss, macrothrombocytopenia, and cardiovascular diseases. The solution structure of the complex between the N-terminal inhibitory domain, DID, and the C-terminal DAD, resolved by NMR spectroscopy shows only transient interactions between DID and the basic motif of DAD, resembling those found in encounter complexes. Cross-linking studies placed the RRKR motif into the negatively charged cavity of DID. Neutralizing the cavity resulted in a 5-fold decrease in the binding affinity and 4-fold decrease in the association rate constant of DAD for DID, indicating that the RRKR interactions with DID form a productive encounter complex. A DIAPH1 mutant containing a neutralized RRKR binding cavity shows excessive colocalization with actin and is unresponsive to RAGE stimulation. This is the first demonstration of a specific alteration of the surfaces responsible for productive encounter complexation with implications for human pathology.

Glucagon-like peptide-1 receptor signaling modifies the extent of diabetic kidney disease through dampening the receptor for advanced glycation end products-induced inflammation.

Glucagon like peptide-1 (GLP-1) is a hormone produced and released by cells of the gastrointestinal tract following meal ingestion. GLP-1 receptor agonists (GLP-1RA) exhibit kidney-protective actions through poorly understood mechanisms. Here we interrogated whether the receptor for advanced glycation end products (RAGE) plays a role in mediating the actions of GLP-1 on inflammation and diabetic kidney disease. Mice with deletion of the GLP-1 receptor displayed an abnormal kidney phenotype that was accelerated by diabetes and improved with co-deletion of RAGE in vivo. Activation of the GLP-1 receptor pathway with liraglutide, an anti-diabetic treatment, downregulated kidney RAGE, reduced the expansion of bone marrow myeloid progenitors, promoted M2-like macrophage polarization and lessened markers of kidney damage in diabetic mice. Single cell transcriptomics revealed that liraglutide induced distinct transcriptional changes in kidney endothelial, proximal tubular, podocyte and macrophage cells, which were dominated by pathways involved in nutrient transport and utilization, redox sensing and the resolution of inflammation. The kidney-protective action of liraglutide was corroborated in a non-diabetic model of chronic kidney disease, the subtotal nephrectomised rat. Thus, our findings identify a novel glucose-independent kidney-protective action of GLP-1-based therapies in diabetic kidney disease and provide a valuable resource for exploring the cell-specific kidney transcriptional response ensuing from pharmacological GLP-1R agonism.

Compromised DNA repair is responsible for diabetes-associated fibrosis.

Diabetes-associated organ fibrosis, marked by elevated cellular senescence, is a growing health concern. Intriguingly, the mechanism underlying this association remained unknown. Moreover, insulin alone can neither reverse organ fibrosis nor the associated secretory phenotype, favoring the exciting notion that thus far unknown mechanisms must be operative. Here, we show that experimental type 1 and type 2 diabetes impairs DNA repair, leading to senescence, inflammatory phenotypes, and ultimately fibrosis. Carbohydrates were found to trigger this cascade by decreasing the NAD+ /NADH ratio and NHEJ-repair in vitro and in diabetes mouse models. Restoring DNA repair by nuclear over-expression of phosphomimetic RAGE reduces DNA damage, inflammation, and fibrosis, thereby restoring organ function. Our study provides a novel conceptual framework for understanding diabetic fibrosis on the basis of persistent DNA damage signaling and points to unprecedented approaches to restore DNA repair capacity for resolution of fibrosis in patients with diabetes.

S100P binds to RAGE and activates ERK/NF-κB signaling to promote osteoclast differentiation and activity.

S100 calcium-binding protein P (S100P) is a secretory protein that is expressed in various healthy tissues and tumors. Megakaryocyte-secreted S100P promotes osteoclast differentiation and function; however, its receptor and cellular signaling in osteoclasts remain unclear. Receptor for advanced glycation end products (RAGE), which is the receptor for S100P on cancer cells, was expressed in osteoclast precursors, and S100P-RAGE binding was confirmed through co-immunoprecipitation. Additionally, the phosphorylation of ERK and NF-κB was increased in S100P-stimulated osteoclast precursors but was inhibited by addition of the RAGE antagonistic peptide (RAP). S100P-induced osteoclast differentiation and excessive bone resorption activity were also reduced by the addition of RAP. This study demonstrates that S100P, upon binding with RAGE, activates the ERK and NF-κB signaling pathways in osteoclasts, leading to increased cell differentiation and bone resorption activity.

Vitamin D supplementation modulates glycated hemoglobin (HBA1c) in diabetes mellitus.

Diabetes is a metabolic illness that increases protein glycosylation in hyperglycemic conditions, which can have an impact on almost every organ system in the body. The role of vitamin D in the etiology of diabetes under RAGE (receptor for advanced glycation end products) stress has recently received some attention on a global scale. Vitamin D's other skeletal benefits have generated a great deal of research. Vitamin D's function in the development of type 1 and type 2 diabetes is supported by the discovery of 1,25 (OH)2D3 and 1-Alpha-Hydroylase expression in immune cells, pancreatic beta cells, and several other organs besides the bone system. A lower HBA1c level, metabolic syndrome, and diabetes mellitus all seems to be associated with vitamin D insufficiency. Most of the cross-sectional and prospective observational studies that were used to gather human evidence revealed an inverse relationship between vitamin D level and the prevalence or incidence of elevated HBA1c in type 2 diabetes. Several trials have reported on the impact of vitamin D supplementation for glycemia or incidence of type 2 diabetes, with varying degrees of success. The current paper examines the available data for a relationship between vitamin D supplementation and HBA1c level in diabetes and discusses the biological plausibility of such a relationship.

High-fat diet causes endothelial dysfunction in the mouse ophthalmic artery.

Obesity is a significant health concern that leads to impaired vascular function and subsequent abnormalities in various organs. The impact of obesity on ocular blood vessels, however, remains largely unclear. In this study, we examined the hypothesis that obesity induced by high-fat diet produces vascular endothelial dysfunction in the ophthalmic artery. Mice were subjected to a high-fat diet for 20 weeks, while age-matched controls were maintained on a standard diet. Reactivity of isolated ophthalmic artery segments was assessed in vitro. Reactive oxygen species (ROS) were quantified in cryosections by dihydroethidium (DHE) staining. Redox gene expression was determined in ophthalmic artery explants by real-time PCR. Furthermore, the expression of nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2), the receptor for advanced glycation end products (RAGE), and of the lectin-like oxidized low-density-lipoprotein receptor-1 (LOX-1) was determined in cryosections using immunofluorescence microscopy. Ophthalmic artery segments from mice on a high-fat diet exhibited impaired vasodilation responses to the endothelium-dependent vasodilator acetylcholine, while endothelium-independent responses to nitroprusside remained preserved. DHE staining intensity in the vascular wall was notably stronger in mice on a high-fat diet. Messenger RNA expression for NOX2 was elevated in the ophthalmic artery of mice subjected to high fat diet. Likewise, immunostainings revealed increased expression of NOX2 and of RAGE, but not of LOX-1. These findings suggest that a high-fat diet triggers endothelial dysfunction by inducing oxidative stress in the ophthalmic artery via involvement of RAGE and NOX2.

Molecular Basis for the Involvement of Mammalian Serum Albumin in the AGE/RAGE Axis: A Comprehensive Computational Study.

In mammals, glycated serum albumin (gSA) contributes to the pathogenesis of many metabolic diseases by activating the receptors (RAGE) for advanced glycation end products (AGEs). Many aspects of the gSA-RAGE interaction remain unknown. The purpose of the present paper was to study the interaction of glycated human albumin (gHSA) with RAGE using molecular modeling methods. Ten models of gHSA modified with different lysine residues to carboxymethyl-lysines were prepared. Complexes of gHSA-RAGE were obtained by the macromolecular docking method with subsequent molecular dynamics simulation (MD). According to the MD, the RAGE complexes with gHSA glycated at Lys233, Lys64, Lys525, Lys262 and Lys378 are the strongest. Three-dimensional models of the RAGE dimers with gHSA were proposed. Additional computational experiments showed that the binding of fatty acids (FAs) to HSA does not affect the ability of Lys525 (the most reactive lysine) to be glycated. In contrast, modification of Lys525 reduces the affinity of albumin for FA. The interspecies differences in the molecular structure of albumin that may affect the mechanism of the gSA-RAGE interaction were discussed. The obtained results will help us to learn more about the molecular basis for the involvement of serum albumin in the AGE/RAGE axis and improve the methodology for studying cellular signaling pathways involving RAGE.

Association of four differently processed diets with plasma and urine advanced glycation end products and serum soluble receptor for advanced glycation end products concentration in healthy dogs.

Advanced glycation end products (AGEs), formed via the Maillard reaction (MR) during processing of foods, have been implicated in inflammatory and degenerative diseases in human beings. Cellular damage is primarily caused by AGE binding with the receptor for AGEs (RAGE) on cell membranes. An isoform of RAGE, soluble RAGE (sRAGE), acts as a decoy receptor binding circulating AGEs preventing cellular activation. Pet food manufacturing involves processing methods similar to human food processing that may increase dietary AGEs (dAGEs). We hypothesized that diet, plasma and urine AGEs, and serum sRAGE concentrations would differ between thermally processed diets. This study examined the association of four differently processed diets: ultra-processed canned wet food (WF); ultra-processed dry food (DF); moderately processed air-dried food (ADF) and minimally processed mildly cooked food (MF) on total plasma levels of the AGEs, carboxymethyllysine (CML), carboxyethyllysine (CEL), methylglyoxal hydroimidazolone-1, glyoxal hydroimidazolone-1, argpyrimidine, urine CML, CEL and lysinoalanine, and serum sRAGE concentration. Ultra-high-performance liquid chromatography-tandem mass spectrometry was used to measure AGEs. sRAGE concentration was measured using a commercial canine-specific enzyme-linked immunosorbent assay kit. Total dAGEs (mg/100 kcal as fed) were higher in WF than in other diets. Plasma total AGEs (nM/50 µL) were significantly higher with WF, with no difference found between DF, ADF, and MF; however, ADF was significantly higher than MF. Urine CML (nmol AGEs/mmol creatinine) was significantly higher with DF than with WF and MF. There were no significant differences in total urine AGEs or serum sRAGE concentration between diets. In conclusion, different methods of processing pet foods are associated with varied quantities of AGEs influencing total plasma AGE concentration in healthy dogs. Serum sRAGE concentration did not vary across diets but differences in total AGE/sRAGE ratio were observed between MF and WF and, ADF and DF.

[Research Progress in the Role of Advanced Glycation End Products in the Pathogenesis of Sarcopenia].

Sarcopenia is an age-related condition characterized by a decrease in muscle mass and a decline in muscle strength.Sarcopenia increases the risk of falls,severely affecting the quality of life of patients,and it may be associated with various age-related chronic diseases.Advanced glycation end products(AGEs)are a class of stable glycation products produced by condensation,rearrangement,cleavage,and oxidative modification between the free amino groups of proteins,lipids or nucleic acids and the free carbonyl groups of reducing sugars.Studies have revealed associations of AGEs with muscle mass,muscle strength,and sarcopenia.AGEs can lead to hardening of the extracellular matrix of skeletal muscle through glycation cross-linking.The binding of AGEs to receptors induces inflammation and oxidative stress,consequently resulting in decreases in muscle mass and muscle strength.Therefore,AGEs may play a role in the occurrence and development of sarcopenia.This review summarizes the role of AGEs in the pathogenesis of sarcopenia,offering theoretical support for probing into the mechanisms underlying sarcopenia.

Differential gene expression analysis of RAGE-S100A6 complex for target selection and the design of novel inhibitors for anticancer drug discovery.

Receptor for advanced glycation end products (RAGE), a member of the immunoglobulin family, interactions with its ligands trigger downstream signaling and induce an inflammatory response linked to diabetes, inflammation, carcinogenesis, cardiovascular disease, and a variety of other human disorders. The interaction of RAGE and S100A6 has been associated with a variety of malignancies. For the control of RAGE-related illnesses, there is a great demand for more specialized drug options. To identify the most effective target for combating human malignancies associated with RAGE-S100A6 complex, we conducted single and differential gene expression analyses of S100A6 and RAGE, comparing normal and malignant tissues. Further, a structure-based virtual screening was conducted using the ZINC15 database. The chosen compounds were then subjected to a molecular docking investigation on the RAGE active site region, recognized by the various cancer-related RAGE ligands. An optimized RAGE structure was screened against a library of drug-like molecules. The screening results suggested that three promising compounds were presented as the top acceptable drug-like molecules with a high binding affinity at the RAGE V-domain catalytic region. We depicted that these compounds may be potential RAGE inhibitors and could be used to produce a successful medication against human cancer and other RAGE-related diseases based on their various assorted parameters, binding energy, hydrogen bonding, ADMET characteristics, etc. MD simulation on a time scale of 50 ns was used to test the stability of the RAGE-inhibitor complexes. Therefore, targeting RAGE and its ligands using these drug-like molecules may be an effective therapeutic approach.

Increased alpha-synuclein and neuroinflammation in the substantia nigra triggered by systemic inflammation are reversed by targeted inhibition of the receptor for advanced glycation end products (RAGE).

The receptor for advanced glycation end products (RAGE) is a protein of the immunoglobulin superfamily capable of regulating inflammation. Considering the role of this receptor in the initiation and establishment of neuroinflammation, and the limited understanding of the function of RAGE in the maintenance of this condition, this study describes the effects of RAGE inhibition in the brain, through an intranasal treatment with the antagonist FPS-ZM1, in an animal model of chronic neuroinflammation induced by acute intraperitoneal injection of lipopolysaccharide (LPS). Seventy days after LPS administration (2 mg/kg, i.p.), Wistar rats received, intranasally, 1.2 mg of FPS-ZM1 over 14 days. On days 88 and 89, the animals were submitted to the open-field test and were killed on day 90 after the intraperitoneal injection of LPS. Our results indicate that blockade of encephalic RAGE attenuates LPS-induced chronic neuroinflammation in different brain regions. Furthermore, we found that intranasal FPS-ZM1 administration reduced levels of gliosis markers, RAGE ligands, and α-synuclein in the substantia nigra pars compacta. Additionally, the treatment also reversed the increase in S100 calcium-binding protein B (RAGE ligand) in the cerebrospinal fluid and the cognitive-behavioral deficits promoted by LPS-less time spent in the central zone of the open-field arena (more time in the lateral zones), decreased total distance traveled, and increased number of freezing episodes. In summary, our study demonstrates the prominent role of RAGE in the maintenance of a chronic neuroinflammatory state triggered by a single episode of systemic inflammation and also points to possible future RAGE-based therapeutic approaches to treat conditions in which chronic neuroinflammation and increased α-synuclein levels could play a relevant role, such as in Parkinson's disease.

AMPK boosts ADAM10 shedding activity in human aortic endothelial cells by promoting Rab14-dependent ADAM10 cell surface translocation.

A disintegrin and metalloprotease 10 (ADAM10) regulates the expression of cell surface receptors such as tumor necrosis factor receptor 1, toll-like receptor 4, and the receptor for advanced glycation end products (RAGE) by cleaving their extracellular regions. To function as a sheddase, ADAM10 should translocate from the intracellular compartments to the cell surface, but the translocation mechanism remains unclear. In this study, we explored the possible role of adenosine monophosphate-activated protein kinase (AMPK) in the induction of ADAM10 shedding activity. In cultured human aortic endothelial cells (HAECs), 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), an AMPK activator, boosted ADAM10 cell surface translocation and ectodomain shedding of RAGE. ADAM10 inhibition with GI 254023X and ADAM10 siRNA silencing both prevented AICAR-induced RAGE ectodomain shedding. AICAR increased AMPK phosphorylation as well. Both Compound C-mediated AMPK inhibition and AMPKα1-siRNA-mediated AMPK depletion suppressed AICAR-induced ADAM10 cell surface translocation and RAGE ectodomain shedding. On the other hand, siRNA knockdown of Rab14, a small GTPase that facilitates the intracellular trafficking of transmembrane proteins, prevented AICAR-induced ADAM10 cell surface translocation and RAGE ectodomain shedding. In conclusion, AMPK activation is an obvious inducer of ADAM10 shedding activity. Our findings suggest that AMPK boosts ADAM10 shedding activity in HAECs by promoting Rab14-dependent ADAM10 cell surface translocation.

Effects of sevoflurane on lung epithelial permeability in experimental models of acute respiratory distress syndrome.

BACKGROUND: Preclinical studies in acute respiratory distress syndrome (ARDS) have suggested that inhaled sevoflurane may have lung-protective effects and clinical trials are ongoing to assess its impact on major clinical outcomes in patients with ARDS. However, the underlying mechanisms of these potential benefits are largely unknown. This investigation focused on the effects of sevoflurane on lung permeability changes after sterile injury and the possible associated mechanisms. METHODS: To investigate whether sevoflurane could decrease lung alveolar epithelial permeability through the Ras homolog family member A (RhoA)/phospho-Myosin Light Chain 2 (Ser19) (pMLC)/filamentous (F)-actin pathway and whether the receptor for advanced glycation end-products (RAGE) may mediate these effects. Lung permeability was assessed in RAGE-/- and littermate wild-type C57BL/6JRj mice on days 0, 1, 2, and 4 after acid injury, alone or followed by exposure at 1% sevoflurane. Cell permeability of mouse lung epithelial cells was assessed after treatment with cytomix (a mixture of TNFɑ, IL-1ß, and IFNγ) and/or RAGE antagonist peptide (RAP), alone or followed by exposure at 1% sevoflurane. Levels of zonula occludens-1, E-cadherin, and pMLC were quantified, along with F-actin immunostaining, in both models. RhoA activity was assessed in vitro. RESULTS: In mice after acid injury, sevoflurane was associated with better arterial oxygenation, decreased alveolar inflammation and histological damage, and non-significantly attenuated the increase in lung permeability. Preserved protein expression of zonula occludens-1 and less increase of pMLC and actin cytoskeletal rearrangement were observed in injured mice treated with sevoflurane. In vitro, sevoflurane markedly decreased electrical resistance and cytokine release of MLE-12 cells, which was associated with higher protein expression of zonula occludens-1. Improved oxygenation levels and attenuated increase in lung permeability and inflammatory response were observed in RAGE-/- mice compared to wild-type mice, but RAGE deletion did not influence the effects of sevoflurane on permeability indices after injury. However, the beneficial effect of sevoflurane previously observed in wild-type mice on day 1 after injury in terms of higher PaO2/FiO2 and decreased alveolar levels of cytokines was not found in RAGE-/- mice. In vitro, RAP alleviated some of the beneficial effects of sevoflurane on electrical resistance and cytoskeletal rearrangement, which was associated with decreased cytomix-induced RhoA activity. CONCLUSIONS: Sevoflurane decreased injury and restored epithelial barrier function in two in vivo and in vitro models of sterile lung injury, which was associated with increased expression of junction proteins and decreased actin cytoskeletal rearrangement. In vitro findings suggest that sevoflurane may decrease lung epithelial permeability through the RhoA/pMLC/F-actin pathway.

RAGE inhibition alleviates lipopolysaccharides-induced lung injury via directly suppressing autophagic apoptosis of type II alveolar epithelial cells.

BACKGROUND: Advanced glycation end product receptor (RAGE) acts as a receptor of pro-inflammatory ligands and is highly expressed in alveolar epithelial cells (AECs). Autophagy in AECs has received much attention recently. However, the roles of autophagy and RAGE in the pathogenesis of acute lung injury remain unclear. Therefore, this study aimed to explore whether RAGE activation signals take part in the dysfunction of alveolar epithelial barrier through autophagic death. METHODS: Acute lung injury animal models were established using C57BL/6 and Ager gene knockout (Ager -/- mice) mice in this study. A549 cells and primary type II alveolar epithelial (ATII) cells were treated with siRNA to reduce Ager gene expression. Autophagy was inhibited by 3-methyladenine (3-MA). Lung injury was assessed by histopathological examination. Cell viability was estimated by cell counting kit-8 (CCK-8) assay. The serum and bronchoalveolar lavage fluid (BALF) levels of interleukin (IL)-6, IL-8 and soluble RAGE (sRAGE) were evaluated by Enzyme-linked immunosorbent assay (ELISA). The involvement of RAGE signals, autophagy and apoptosis was assessed using western blots, immunohistochemistry, immunofluorescence, transmission electron microscopy and TUNEL test. RESULTS: The expression of RAGE was promoted by lipopolysaccharide (LPS), which was associated with activation of autophagy both in mice lung tissues and A549 cells as well as primary ATII cells. sRAGE in BALF was positively correlated with IL-6 and IL-8 levels. Compared with the wild-type mice, inflammation and apoptosis in lung tissues were alleviated in Ager-/- mice. Persistently activated autophagy contributed to cell apoptosis, whereas the inhibition of autophagy by 3-MA protected lungs from damage. In addition, Ager knockdown inhibited LPS-induced autophagy activation and attenuated lung injury. In vitro, knockdown of RAGE significantly suppressed the activation of LPS-induced autophagy and apoptosis of A549 and primary ATII cells. Furthermore, RAGE activated the downstream STAT3 signaling pathway. CONCLUSION: RAGE plays an essential role in the pathogenesis of ATII cells injury. Our results suggested that RAGE inhibition alleviated LPS-induced lung injury by directly suppressing autophagic apoptosis of alveolar epithelial cells.

Immunological methods for the determination of AGE-RAGE axis generated glutathionylated and carbonylated proteins as oxidative stress markers.

Interaction of advanced glycation end products (AGE) with their receptor i.e. receptor for advanced glycation end products (RAGE), better understood as AGE-RAGE axis, generates oxidative and inflammatory stress. The generated stress extent, in turn aggravates the AGE and RAGE levels through a vicious self propagation cycle. The associated oxidation and inflammation culminates in modifications and subsequent detrimental state of cellular macromolecules, including nucleic acids and proteins, manifesting multiple diseased conditions. Under normal physiological state, fewer carbonyl group(s) and glutathione, a tripeptide antioxidant may be added to proteins during post-translational modifications, recognized as carbonylation and glutathionylation, respectively. However, under oxidative and inflammatory stress conditions, protein carbonylation and glutathionylation are caused to considerably greater extents, leading to numerous diseased complications. Thereby, increased protein carbonylation and glutathionylation could be used as predictive markers of oxidative and inflammatory stress. The AGE-RAGE axis generated oxidatively modified proteins can be screened via assessing the protein carbonylation and glutathionylation. The present article focuses on most widely used protein carbonylation and glutathionylation based assays for quantifying the AGE-RAGE axis mediated oxidative and inflammatory stress.

The Association of HMGB1 and RAGE Gene Polymorphisms with IgA Vasculitis.

High-mobility group box 1 (HMGB1) is a pleiotropic cytokine that propagates inflammation by its extracellular action of interacting with the receptor for advanced glycation end products (RAGE). Both HMGB1 and RAGE play multiple roles in the pathogenesis of a variety of inflammatory and autoimmune diseases. We investigated the association of five single-nucleotide polymorphisms (SNPs) of the HMGB1 gene (rs1412125, rs2249825, rs1045411, rs1060348, rs41369348) and four SNPs of the RAGE gene (rs1800624, rs1800625, rs2070600, rs3134940) with the susceptibility and clinical features of paediatric patients with IgA vasculitis (IgAV), also known as Henoch-Schönlein's purpura. This case‒control study included 103 children with IgAV (experimental group) and 150 age-matched healthy individuals (control group). The strength of the association between different groups and alleles or genotypes of HMGB1 and RAGE was estimated using odds ratios (ORs) and 95% confidence intervals (CIs). The HMGB1 polymorphisms rs41369348, rs1045411, rs2249825 and rs1412125 were associated with the development of generalized purpuric rash, and rs1412125 was associated with IgAV nephritis (IgAVN). The RAGE polymorphism rs2070600 might be linked to the development of arthritis in IgAV patients. There was no statistically significant association between the analysed polymorphisms and susceptibility to IgAV. This is the first study to propose an association between several HMGB1 and RAGE polymorphisms and different phenotypes in the clinical course of IgAV in a paediatric population. Further research on other polymorphisms of HMGB1 and RAGE should be conducted in a larger number of patients.

Leukocyte surface biomarkers implicate deficits of innate immunity in sporadic Alzheimer's disease.

INTRODUCTION: Blood-based diagnostics and prognostics in sporadic Alzheimer's disease (AD) are important for identifying at-risk individuals for therapeutic interventions. METHODS: In three stages, a total of 34 leukocyte antigens were examined by flow cytometry immunophenotyping. Data were analyzed by logistic regression and receiver operating characteristic (ROC) analyses. RESULTS: We identified leukocyte markers differentially expressed in the patients with AD. Pathway analysis revealed a complex network involving upregulation of complement inhibition and downregulation of cargo receptor activity and Aß clearance. A proposed panel including four leukocyte markers - CD11c, CD59, CD91, and CD163 - predicts patients' PET Aß status with an area under the curve (AUC) of 0.93 (0.88 to 0.97). CD163 was the top performer in preclinical models. These findings have been validated in two independent cohorts. CONCLUSION: Our finding of changes on peripheral leukocyte surface antigens in AD implicates the deficit in innate immunity. Leukocyte-based biomarkers prove to be both sensitive and practical for AD screening and diagnosis.

Paracrine Signals in Calcified Conditioned Media Elicited Differential Responses in Primary Aortic Vascular Smooth Muscle Cells and in Adventitial Fibroblasts.

Our goal was to determine if paracrine signals from different aortic layers can impact other cell types in the diabetic microenvironment, specifically medial vascular smooth muscle cells (VSMCs) and adventitial fibroblasts (AFBs). The diabetic hyperglycemic aorta undergoes mineral dysregulation, causing cells to be more responsive to chemical messengers eliciting vascular calcification. Advanced glycation end-products (AGEs)/AGE receptors (RAGEs) signaling has been implicated in diabetes-mediated vascular calcification. To elucidate responses shared between cell types, pre-conditioned calcified media from diabetic and non-diabetic VSMCs and AFBs were collected to treat cultured murine diabetic, non-diabetic, diabetic RAGE knockout (RKO), and non-diabetic RKO VSMCs and AFBs. Calcium assays, western blots, and semi-quantitative cytokine/chemokine profile kits were used to determine signaling responses. VSMCs responded to non-diabetic more than diabetic AFB calcified pre-conditioned media. AFB calcification was not significantly altered when VSMC pre-conditioned media was used. No significant changes in VSMCs signaling markers due to treatments were reported; however, genotypic differences existed. Losses in AFB α-smooth muscle actin were observed with diabetic pre-conditioned VSMC media treatment. Superoxide dismutase-2 (SOD-2) increased with non-diabetic calcified + AGE pre-conditioned VSMC media, while same treatment decreased diabetic AFBs levels. Overall, non-diabetic and diabetic pre-conditioned media elicited different responses from VSMCs and AFBs.

The Remarkable Roles of the Receptor for Advanced Glycation End Products (RAGE) and Its Soluble Isoforms in COVID-19: The Importance of RAGE Pathway in the Lung Injuries.

The respiratory symptoms of acute respiratory distress syndrome (ARDS) in the coronavirus disease 2019 (COVID-19) patients is associated with accumulation of pre-inflammatory molecules such as advanced glycation end-products (AGES), calprotectin, high mobility group box family-1 (HMGB1), cytokines, angiotensin converting enzyme 2 (ACE2), and other molecules in the alveolar space of lungs and plasma. The receptor for advanced glycation end products (RAGEs), which is mediated by the mitogen-activated protein kinase (MAPK), plays a critical role in the severity of chronic inflammatory diseases such as diabetes mellitus (DM) and ARDS. The RAGE gene is most expressed in the alveolar epithelial cells (AECs) of the pulmonary system. Several clinical trials are now being conducted to determine the possible association between the levels of soluble isoforms of RAGE (sRAGE and esRAGE) and the severity of the disease in patients with ARDS and acute lung injury (ALI). In the current article, we reviewed the most recent studies on the RAGE/ligands axis and sRAGE/esRAGE levels in acute respiratory illness, with a focus on COVID-19-associated ARDS (CARDS) patients. According to the research conducted so far, sRAGE/esRAGE measurements in patients with CARDS can be used as a powerful chemical indicator among other biomarkers for assessment of early pulmonary involvement. Furthermore, inhibiting RAGE/MAPK and Angiotensin II receptor type 1 (ATR1) in CARDS patients can be a powerful strategy for diminishing cytokine storm and severe respiratory symptoms.

Plasma levels of soluble RAGE, AGEs and AOPPs at the early stage of amyotrophic lateral sclerosis: A preliminary study.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder with largely unknown pathogenesis and no effective cure. It is believed that several, not mutually exclusive mechanisms contribute to the pathogenesis and progression of this disease, including, among others, elevated oxidative stress, excitotoxicity, increased neuroinflammation, and protein aggregation. Receptor for advanced glycation end products (RAGE) is a part of immunoglobulin superfamily; it is believed to participate in ALS pathogenesis. OBJECTIVES: Our previous studies on ALS demonstrated that RAGE is likely one of the key players in ALS, acting on its own and in tandem with its oxidative stress and pro-inflammatory ligands, such as advanced glycation end products (AGEs) or advanced oxidation protein products (AOPPs). In this study, based on our previous results, we aimed to establish blood levels of soluble RAGE, AGE and AOPP in ALS patients. MATERIAL AND METHODS: Forty-six coded and anonymized surplus plasma samples from ALS patients and non-neurological control were used in the study. The plasma levels of RAGE, AGE and AOPP were measured using enzyme-linked immunosorbent assay (ELISA) commercially available kits. Statistical evaluation of data was performed using one-way non-parametric analysis of variance (ANOVA) with Kruskal-Wallis post hoc test. RESULTS: Our results revealed a decline in soluble RAGE level, concurrent with an increase in the levels of AGEs and AOPPs in blood samples from ALS patients, signifying a loss of neuroprotective form of RAGE and a simultaneous increase in AGE and AOPP production and uptake at the early stage of the disease. CONCLUSIONS: The results obtained from our study indicate that further longitudinal study of RAGE, AGE and AOPP levels would be beneficial, outlining the dynamics between RAGE and its ligand levels as the disease progresses, and making them valuable diagnostic tools and potential therapeutic targets.