Monocyte Chemoattractant Protein-1 Signaling Research Articles

Prenatal Programming of Monocyte Chemotactic Protein-1 Signaling in Autism Susceptibility.

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that involves functional and structural defects in selective central nervous system (CNS) regions, harming the individual capability to process and respond to external stimuli, including impaired verbal and non-verbal communications. Etiological causes of ASD have not been fully clarified; however, prenatal activation of the innate immune system by external stimuli might infiltrate peripheral immune cells into the fetal CNS and activate cytokine secretion by microglia and astrocytes. For instance, genomic and postmortem histological analysis has identified proinflammatory gene signatures, microglia-related expressed genes, and neuroinflammatory markers in the brain during ASD diagnosis. Active neuroinflammation might also occur during the developmental stage, promoting the establishment of a defective brain connectome and increasing susceptibility to ASD after birth. While still under investigation, we tested the hypothesis whether the monocyte chemoattractant protein-1 (MCP-1) signaling is prenatally programmed to favor peripheral immune cell infiltration and activate microglia into the fetal CNS, setting susceptibility to autism-like behavior. In this review, we will comprehensively provide the current understanding of the prenatal activation of MCP-1 signaling by external stimuli during the developmental stage as a new selective node to promote neuroinflammation, brain structural alterations, and behavioral defects associated to ASD diagnosis.

MCP-1 Signaling Disrupts Social Behavior by Modulating Brain Volumetric Changes and Microglia Morphology.

Autism spectrum disorder (ASD) is a disease characterized by reduced social interaction and stereotypic behaviors and related to macroscopic volumetric changes in cerebellar and somatosensory cortices (SPP). Epidemiological and preclinical models have confirmed that a proinflammatory profile during fetal development increases ASD susceptibility after birth. Here, we aimed to globally identify the effect of maternal exposure to high-energy dense diets, which we refer to as cafeteria diet (CAF) on peripheral and central proinflammatory profiles, microglia reactivity, and volumetric brain changes related to assisting defective social interaction in the mice offspring. We found a sex-dependent effect of maternal exposure to CAF diet or inoculation of the dsARN mimetic Poly (I:C) on peripheral proinflammatory and social interaction in the offspring. Notably, maternal exposure to CAF diet impairs social interaction and favors an increase in anxiety in male but not female offspring. Also, CAF diet exposure or Poly (I:C) inoculation during fetal programming promote peripheral proinflammatory profile in the ASD-diagnosed male but not in females. Selectively, we found a robust accumulation of the monocyte chemoattractant protein-1 (MCP-1) in plasma of ASD-diagnosed males exposed to CAF during fetal development. Biological assessment of MCP-1 signaling in brain confirms that systemic injection of MCP-1-neutralizing antibody reestablished social interaction and blocked anxiety, accompanied by a reduction in cerebellar lobule X (CbX) volume and an increase volume of the primary somatosensory (SSP) cortex in male offspring. These data highlight the contribution of diet-dependent MCP-1 signaling on volumetric brain changes and microglia morphology promoting ASD-like behavior in male mice.

Monocyte-Chemoattractant Protein-1 Levels in Human Atherosclerotic Lesions Associate With Plaque Vulnerability.

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Abstract P771: Monocyte-Chemoattractant Protein-1 Levels in Human Carotid Atherosclerosis Associate With Hallmarks of Plaque Vulnerability

Background: Monocyte chemoattractant protein-1 (MCP-1) is a chemokine recruiting monocytes to the atherosclerotic plaque. Experimental, genetic, and epidemiological data support a key role of MCP-1 in atherosclerosis. Yet, the translational potential of targeting MCP-1 signaling for lowering vascular risk is limited by the lack of data on plaque MCP-1 activity in human atherosclerosis. Methods: We measured MCP-1 levels in human plaque samples from 1,199 patients undergoing carotid endarterectomy from the Athero-Express Biobank. We explored associations of plaque MCP-1 levels with histopathological features of plaque vulnerability, clinical plaque instability (symptomatic vs. asymptomatic plaque), molecular markers of plaque inflammation and remodeling, and with incident vascular events up to three years after plaque removal. Results: MCP-1 plaque levels were associated with individual histopathological hallmarks of plaque vulnerability (large lipid core, low collagen, high macrophage burden, low smooth muscle cell burden, intraplaque hemorrhage), as well as with a cumulative vulnerability index (range 0-5, beta: 0.42, 95%CI: 0.30-0.53, p=5.4x10 -13 ) independently of age, sex, and conventional vascular risk factors. Furthermore, MCP-1 levels were higher among patients with symptomatic, as compared to asymptomatic plaques (p=0.0001) and were associated with the levels of pro-inflammatory cytokines involved in leukocyte adhesion, as well as with matrix metalloproteinase activity in the plaque. In the follow-up analyses, MCP-1 levels were associated with a higher risk of peri-procedural events (up to 30 days after surgery). Conclusions: Our findings highlight a role of MCP-1 in human plaque vulnerability, the leading mechanism underlying vascular events like stroke and myocardial infarction. As such, they suggest that interfering with MCP-1 signaling in patients with established atherosclerosis could lower vascular risk.

Circulating Monocyte Chemoattractant Protein-1 and Risk of Stroke: Meta-Analysis of Population-Based Studies Involving 17 180 Individuals.

Rationale: Proinflammatory cytokines have been identified as potential targets for lowering vascular risk. Experimental evidence and Mendelian randomization suggest a role of MCP-1 (monocyte chemoattractant protein-1) in atherosclerosis and stroke. However, data from large-scale observational studies are lacking. Objective: To determine whether circulating levels of MCP-1 are associated with risk of incident stroke in the general population. Methods and Results: We used previously unpublished data on 17 180 stroke-free individuals (mean age, 56.7±8.1 years; 48.8% men) from 6 population-based prospective cohort studies and explored associations between baseline circulating MCP-1 levels and risk of any stroke, ischemic stroke, and hemorrhagic stroke during a mean follow-up interval of 16.3 years (280 522 person-years at risk; 1435 incident stroke events). We applied Cox proportional-hazards models and pooled hazard ratios (HRs) using random-effects meta-analyses. After adjustments for age, sex, race, and vascular risk factors, higher MCP-1 levels were associated with increased risk of any stroke (HR per 1-SD increment in ln-transformed MCP-1, 1.07; 95% CI, 1.01-1.14). Focusing on stroke subtypes, we found a significant association between baseline MCP-1 levels and higher risk of ischemic stroke (HR, 1.11 [1.02-1.21]) but not hemorrhagic stroke (HR, 1.02 [0.82-1.29]). The results followed a dose-response pattern with a higher risk of ischemic stroke among individuals in the upper quartiles of MCP-1 levels as compared with the first quartile (HRs, second quartile: 1.19 [1.00-1.42]; third quartile: 1.35 [1.14-1.59]; fourth quartile: 1.38 [1.07-1.77]). There was no indication for heterogeneity across studies, and in a subsample of 4 studies (12 516 individuals), the risk estimates were stable after additional adjustments for circulating levels of IL (interleukin)-6 and high-sensitivity CRP (C-reactive protein). Conclusions: Higher circulating levels of MCP-1 are associated with increased long-term risk of stroke. Our findings along with genetic and experimental evidence suggest that MCP-1 signaling might represent a therapeutic target to lower stroke risk.Visual Overview: An online visual overview is available for this article.

Effects of vitamin D supplementation on circulatory YKL-40 and MCP-1 biomarkers associated with vascular diabetic complications: A randomized, placebo-controlled, double-blind clinical trial

AimDiabetic patients predispose to vascular diseases such as nephropathy, and retinopathy. Poor adherence to medical treatment and dietary recommendations in uncontrolled diabetes leads to vascular damages. Vitamin D has been extensively studied and found to be protective against diabetes mellitus. YKL-40 and Monocyte chemoattractant protein-1 (MCP-1) are considered to exert crucial role in diabetes and its complications. Therefore, this study was designed to investigate effects of vitamin D supplementation on serum levels of YKL-40 and MCP-1 involved in the development of diabetic complications. MethodsFor 12 weeks, 48 type 2 diabetic patients enrolled in the trial and randomly were divided into two groups (n = 24 per group), receiving one of the following: 100 μg (4000 IU) vitamin D or placebo. Before and after intervention, serumYKL-40, MCP-1, insulin, IL-6, TNF-α, 25- (OH) vitamin D and HbA1c were measured. ResultsOur results revealed that serum levels of 25 (OH) vitamin D significantly increased in vitamin D group (p < 0.001). Vitamin D supplementation also significantly reduced serum YKL-40 levels (−22.7 vs. −2.4 ng/ml; (p-value = 0.003)). There was a significant decline in MCP-1 concentration in intervention group at the end of the study (−45.7 vs. −0.9 pg/ml; (p = 0.001)). Furthermore, there was a significant decrease in IL-6, fasting insulin and HOMA-IR in intervention group after 3 months supplementation. ConclusionsDaily vitamin D supplementation effectively reduced circulatory YKL-40 and MCP-1 levels in patients with type-2 diabetes and vitamin D deficiency. Vitamin D might contribute in reducing diabetic complications via modulating YKL-40 and MCP-1 signaling pathways.

Age‐induced Hepatic Steatosis and Inflammation of Murine Livers is Influenced by MCP‐1

Aging is linked to the onset and severity of several chronic liver diseases, including non‐alcoholic fatty liver disease, alcoholic liver disease, and hepatitis, which correlate with high levels of macrophage infiltration, inflammation, and immunosenescence. Recent findings suggest that liver macrophages can be divided into two unique subsets: CD68+ embryonically‐derived Kupffer cells and CD11b+ bone marrow derived cells, which exhibit specific cell functions. It is currently unclear how the macrophage populations residing in the liver are phenotypically and functionally impacted by the natural aging process, which may have implications for the onset and progression of inflammatory disease and liver pathology in elderly populations.The aim of this study is to characterize the liver macrophage compartment from young (8–10 week) and aged (18–20 month) C57BL/6 wild‐type mice. First, we identified a significant increase in the total number of F4/80+ macrophages residing in aged livers. Preliminary in vitro studies showed that aged macrophages were primed towards inflammatory reaction, including increased phagocytosis and nitric oxide production, in response to LPS and interferon‐gamma. In addition, the aged macrophage population contained a greater proportion of CD11b+ cells, which are most likely derived from circulating monocytes. To confirm this, we determined that aged hepatocytes secrete enhanced levels of monocyte chemoattractant protein‐1 (MCP‐1), an important signaling molecule for monocyte recruitment following injury. Although aged livers do not show signs of injury or damage, we determined that hepatocytes from aged livers have increased triglyceride content and a shifted fatty acid profile. Of note, the aged mice received the same diet as young controls, and do not show signs of glucose intolerance. Future studies will examine how inhibition of MCP‐1 signaling will impact macrophage recruitment, inflammation, and steatosis in aged livers towards a better understanding of age‐related liver pathology.Support or Funding InformationNIH‐NIBIB Training Grant (T32‐EB001026); NIH‐NIDDK NRSA Fellowship (F31‐DK112633‐01A1); Pittsburgh Liver Research Center Pilot &amp; Feasibility GrantThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Chronic Intracerebroventricular Infusion of Monocyte Chemoattractant Protein-1 Leads to a Persistent Increase in Sweetened Ethanol Consumption During Operant Self-Administration But Does Not Influence Sucrose Consumption in Long-Evans Rats.

Among the evidence implicating neuroimmune signaling in alcohol use disorders are increased levels of the chemokine monocyte chemoattractant protein-1 (MCP-1) in the brains of human alcoholics and animal models of alcohol abuse. However, it is not known whether neuroimmune signaling can directly increase ethanol (EtOH) consumption, and whether MCP-1 is involved in that mechanism. We designed experiments to determine whether MCP-1 signaling itself is sufficient to accelerate or increase EtOH consumption. Our hypothesis was that increasing MCP-1 signaling by directly infusing it into the brain would increase operant EtOH self-administration. We implanted osmotic minipumps to chronically infuse either one of several doses of MCP-1 or vehicle into the cerebral ventricles (intracerebroventricular) of Long-Evans rats and then tested them in the operant self-administration of a sweetened EtOH solution for 8weeks. There was a significant interaction between dose of MCP-1 and sweetened EtOH consumed across the first 4weeks (while pumps were flowing) and across the 8-week experiment. Animals receiving the highest dose of MCP-1 (2μg/d) were the highest consumers of EtOH during weeks 3 through 8. MCP-1 did not influence the acquisition of self-administration (measured across the first 5days), the motivation to consume EtOH (time to lever press or progressive ratio), withdrawal-induced anxiety, or the consumption of sucrose alone. We provide novel evidence that neuroimmune signaling can directly increase chronic operant EtOH self-administration, and that this increase persists beyond the administration of the cytokine. These data suggest that EtOH-induced increases in MCP-1, or increases in MCP-1 due to various other neuroimmune mechanisms, may further promote EtOH consumption. Continued research into this mechanism, particularly using models of alcohol dependence, will help determine whether targeting MCP-1 signaling has therapeutic potential in the treatment of alcohol use disorders.

Potential therapeutic targets for hypoxia-induced pulmonary artery hypertension

BackgroundHypoxic pulmonary artery hypertension (PAH) as a severe pulmonary disease is characterized by changes of pulmonary vascular reconstruction. Mitochondrial ATP-sensitive potassium channel (mitoKATP) was considered as one of factors responsible for the proliferation of hypoxic pulmonary arterial smooth muscle cells (PASMCs), although the exact mechanisms remain unclear.MethodsPulmonary artery hypertension was induced in rats with or without 5-hydroxydecanoate (5-HD). The mean pulmonary artery pressure, morphologic changes, mRNA and protein expressions of voltage-gated potassium channels (Kv1.5 channel), were measured. The concentrations of monocyte chemo-attractant protein-1 (MCP-1) and transforming growth factor-beta1 (TGF-β1) were detected. Furthermore, pulmonary arterial smooth muscle cells (PASMCs) were isolated and cultured with or without hypoxia pretreated with or without 5-HD or/and Kv1.5 inhibitor 4-aminopyridine (4-AP). Mitochondrial membrane potential (Δψm) and the proliferation of PASMCs were detected.Results5-HD significantly prevented the development of PAH by blocking the mitochondrial membrane depolarization, increased the expression of voltage-gated potassium channels, and reduced pulmonary hypertension mediated by TGF-β1 or MCP-1 signaling pathway.ConclusionThe MitoKATP plays an important role in the development of PAH and may be therapeutic target for the treatment of disease.

Proteomic Analysis of Aorta and Protective Effects of Grape Seed Procyanidin B2 in db/db Mice Reveal a Critical Role of Milk Fat Globule Epidermal Growth Factor-8 in Diabetic Arterial Damage

BackgroundAtherosclerosis is one of the major complications of type 2 diabetic patients (T2DM), leading to morbidity and mortality. Grape seed procyanidin B2 (GSPB2) has demonstrated protective effect against atherosclerosis, which is believed to be, at least in part, a result of its antioxidative effects. The aim of this study is to identify the target protein of GSPB2 responsible for the protective effect against atherosclerosis in patients with DM.Methods and ResultsGSPB2 (30 mg/kg body weight/day) were administrated to db/db mice for 10 weeks. Proteomics of the aorta extracts by iTRAQ analysis was obtained from db/db mice. The results showed that expression of 557 proteins were either up- or down-regulated in the aorta of diabetic mice. Among those proteins, 139 proteins were normalized by GSPB2 to the levels comparable to those in control mice. Among the proteins regulated by GSPB2, the milk fat globule epidermal growth factor-8 (MFG-E8) was found to be increased in serum level in T2DM patients; the serum level of MFG-E8 was positively correlated with carotid-femoral pulse wave velocity (CF-PWV). Inhibition of MFG-E8 by RNA interference significantly suppressed whereas exogenous recombinant MFG-E8 administration exacerbated atherogenesis the db/db mice. To gain more insights into the mechanism of action of MFG-E8, we investigated the effects of MFG-E8 on the signal pathway involving the extracellular signal-regulated kinase (ERK) and monocyte chemoattractant protein-1 (MCP-1). Treatment with recombinant MFG-E8 led to increased whereas inhibition of MFG-E8 to decreased expression of MCP-1 and phosphorylation of ERK1/2.ConclusionOur data suggests that MFG-E8 plays an important role in atherogenesis in diabetes through both ERK and MCP-1 signaling pathways. GSPB2, a well-studied antioxidant, significantly inhibited the arterial wall changes favoring atherogenesis in db/db mice by down-regulating MFG-E8 expression in aorta and its serum level. Measuring MFG-E8 serum level could be a useful clinical surrogate prognosticating atherogenesis in DM patients.

Abstract 118: Protein Kinase C-delta Prompts Adventitial Cell Migration Through Regulation of Monocyte Chemoattractant Protein-1 Signaling Pathway in Intimal Hyperplasia

Introduction: Increasing evidence indicates that adventitial cells directly contribute to intimal hyperplasia via migration. Protein kinase C delta (PKC δ), a master mediator of apoptosis of smooth muscle cells (SMCs), is known to mediate expression of monocyte chemoattractant protein-1(MCP-1). In the current study, we hypothesize that PKCδ promotes adventitial cells migration by regulation of MCP-1 signaling pathway in injured arteries. Methods and results: Using isolated carotid SMCs and adventitial fibroblasts, we showed that conditioned media from PKCδ-overexpressing SMCs stimulated migration of adventitial cells, which was blocked by neutralizing MCP-1 or by CCR2 mRNA knocking down. In vivo, PKCδ gene transfer increased SMC apoptosis and levels of MCP-1 and CCR2 expression (MCP-1 protein measured by immunostaining in pixel: 397±20*103 vs 99±18*103, p&lt;0.05; CCR2 mRNA fold induction: 3.45±0.09 vs 1, p&lt;0.01). Next, we evaluated adventitia cells migration by labeling adventitial cells with AdLacZ administered to the adventitial surface immediately following the carotid angioplasty procedure. Overexpresison of PKCδ in SMCs increased the accumulation of adventitial cells in the neointima by close to 10 times (LacZ positive area in pixel of AdPKCd- and AdNull-infected arteries: 769±67*103 vs 84±11*103, p&lt;0.01). Blocking the MCP-1 signaling with an anti-MCP-1 antibody dramatically diminished the number of adventitia-originated cells detected in the medial/intimal region (LacZ positive area in pixel: 357±37*103 vs 894±42*103, p&lt;0.01). The joint treatment of PKCδ and anti-MCP-1 markedly inhibited the I/M ratio by 62% as compared to a 36.3% and 30.8% reduction induced by a single treatment of PKCδ and anti-MCP-1, respectively. None of the treatments altered macrophage infiltration. Conclusions: PKCδ appears to play multiple functions in arterial injury response. Apart from inducing apoptosis, PKCδ regulates migration of adventitial cells via upregulation of the MCP-1/CCR2 signaling axis. A combined strategy targeting both SMC apoptosis and adventitial cell migration may be an efficient approach to inhibit intimal hyperplasia.

Chemokines and Their Receptors in Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a devastating clinical event which results in a high rate of disability and death. At present, no effective treatment is available for ICH. Accumulating evidence suggests that inflammatory responses contribute significantly to the ICH-induced secondary brain outcomes. During ICH, inflammatory cells accumulate at the ICH site attracted by gradients of chemokines. This review summarizes recent progress in ICH studies and the chemoattractants that act during the injury and focuses on and introduces the basic biology of the chemokine monocyte chemoattractant protein-1 (MCP1) and its role in the progression of ICH. Better understanding of MCP1 signaling cascade and the compensation after its inhibition could shed light on the development of effective treatments for ICH.

Resveratrol downregulates acute pulmonary thromboembolism-induced pulmonary artery hypertension via p38 mitogen-activated protein kinase and monocyte chemoattractant protein-1 signaling in rats

AimsIn the present study, we explored the hypothesis that initiation of PH involves the upregulation of monocyte chemoattractant protein-1 (MCP-1) in acute PTE. We evaluated the effects of resveratrol and the role of p38 mitogen-activated protein kinase (MAPK) in this process. Main methodsA rat model of acute PTE was established by infusion of an autologous blood clot into the pulmonary artery through a polyethylene catheter. Rats were randomly divided into 1, 4, and 8hour time groups. Resveratrol, C1142 (a rodent chimeric mAb that neutralizes rat MCP-1) or SB203580 (a p38MAPK specific inhibitor) was administered to the animals beginning 1h prior to the start of the acute PTE protocol. At each time point, the mean pulmonary artery pressure (mPAP), mRNA and protein expressions of MCP-1 were measured. The phosphorylation of p38 MAPK (p-pMAPK) was also detected. Key findingsAcute PTE elicited significant increases in mean pulmonary artery pressure (mPAP), and up-regulated the expression of monocyte chemoattractant protein-1 (MCP-1) and phosphorylation of p38 mitogen-activated protein kinase (p-p38 MAPK). Administration of C1142 markedly reduced mPAP. Furthermore, pre-treatment of rats with resveratrol significantly reduced mPAP and down-regulated the expression of MCP-1, which was associated with robustly suppressed acute PTE-induced p-p38MAPK expression. SignificanceThese findings suggested that MCP-1 was involved in the formation of acute PTE-induced PH, and resveratrol down-regulated the expression of MCP-1 by inhibiting acute PTE-induced p-p38MAPK activation, which contributed to the decrease in PH.

Tumor Necrosis Factor-Like Weak Inducer of Apoptosis (TWEAK) Mediates p38 Mitogen-Activated Protein Kinase Activation and Signal Transduction in Peripheral Blood Mononuclear Cells from Patients with Lupus Nephritis

Forty-two patients with systemic lupus erythematosus (SLE), including 26 patients with renal damage and 16 without, and 20 healthy controls were included in the study. The isolated peripheral blood mononuclear cells (PBMCs) were treated with a p38 inhibitor (SB203580) or anti-tumor necrosis factor-like weak inducer of apoptosis (TWEAK) mAb, with or without phytohemagglutinin/phorbol myristate acetate (PHA/PMA) stimulation. Western blot experiments were used to evaluate the protein expression of TWEAK and p38 MAPK in PBMCs .Next, the contents of interleukin-10 (IL-10) and monocyte chemoattractant protein-1 (MCP-1) in the supernatant were measured by ELISA. The results showed that expression of TWEAK protein in PBMCs from lupus nephritis patients was significantly higher than that from SLE patients without renal damage and healthy controls. PHA/PMA simulation could upregulate the productions of TWEAK and p-p38MAPK in PBMCs from patients with SLE. Anti-TWEAK mAb treatment downregulated both TWEAK and p-p38 MAPK expression in PBMCs, as well as IL-10 and MCP-1 in the supernatant; SB203580 had the same effect on cytokine production in PBMC, but had no effect on the expression of TWEAK. Our results suggested that TWEAK-p38 MAPK-IL-10, MCP-1 signaling pathway in PBMC played an important pathogenic role in lupus nephritis.

S1827 MCP-1 Inhibits DNA Synthesis in Rat Pancreatic Stellate Cells

Activated pancreatic stellate cells (PSCs) synthesize various kinds of cytokines and chemokines including monocyte chemoattractant protein-1 (MCP-1) and play major roles in promoting inflammation and fibrogenesis in the pancreas. MCP-1 is a potent chemotactic factor for leukocytes and it has recently been shown that the target is not restricted. The aim of this study was to investigate whether MCP-1 exerts a biological effect on PSCs. Cultured rat PSCs secreted MCP1 independent of the concentration of transforming growth factor-β 1 (TGF-β 1) in the culture media. Although PSCs lack the typical receptor system (C-C chemokine receptor 2 (CCR2)), MCP-1 inhibited DNA synthesis in PSCs without activation, suggesting the presence of CCR2-independent MCP-1 signaling pathway. Further, MCP-1 inhibited the proliferation of PSCs in which TGF-β 1/Smad pathway was blocked by the dominant-negative Smad2/3 over-expression. MCP-1 did not affect the phosphorylation state of mitogen-activated protein kinase (MAPK), Akt, nor epidermal growth factor receptor (EGFR). Taken together, MCP-1 inhibited DNA synthesis of cultured rat PSCs in an autocrine or paracrine manner without activation and this effect was exerted through CCR2-independent and TGF-β 1/Smad-independent pathway. These data provide new insights to better understand MCP-1 participation in pancreatic inflammation and also to develop a new strategy for its treatment.

In Vitro and in Vivo Mechanotransduction of Focal Adhesion Kinase-Mediated MCP-1 Signaling during Hypertrophic Scar Formation

Introduction: We recently demonstrated that mechanical loading initiates skin fibrosis and modulates inflammatory signaling in a murine model of hypertrophic scarring (HTS). In particular, mechano-sensitive macrophage signaling pathways were implicated in this pathologic process. Focal adhesion kinase (FAK) is a critical mediator of mechanotransduction and has been linked to the release of monocyte chemoattractant protein-1 (MCP-1), a potent macrophage signaling cytokine. We sought to elucidate the role of this mechanotransduction pathway in hypertrophic scar formation.

Role of MCP-1 in tumor necrosis factor-α-induced endothelial dysfunction in type 2 diabetic mice

Tumor necrosis factor-alpha (TNF-alpha) upregulates the expression of monocyte chemoattractant protein-1 (MCP-1) and adhesion molecules in type 2 diabetes. We hypothesized that TNF-alpha and MCP-1 may interact to contribute to the evolution of vascular inflammation and endothelial dysfunction in coronary arterioles in type 2 diabetes. To test this hypothesis, we administered anti-MCP-1 to block MCP-1 signaling in genetically modified mice with type 2 diabetes (Lepr(db)) and in heterozygote (m Lepr(db)) lean control. Anti-MCP-1 partially restored vasodilation to the endothelium-dependent vasodilator acetylcholine in isolated, cannulated, and pressurized coronary arterioles in Lepr(db) mice but did not affect vasodilation in m Lepr(db) mice. Anti-MCP-1 attenuated superoxide production and the protein expression of nitrotyrosine, which is an indicator of peroxynitrite production, in isolated coronary arterioles of Lepr(db) mice. Immunostaining results showed that the expression of MCP-1 and vascular cellular adhesion molecule-1 is colocalized with endothelial cells and macrophages. Anti-TNF-alpha or anti-MCP-1 markedly reduced macrophage infiltration and the number of MCP-1-positive endothelium in Lepr(db) mice. The neutralization of TNF-alpha or anti-MCP-1 reduced the expression of adhesion molecules, suggesting that proinflammatory cytokines interact to amplify the signaling process that leads to vascular dysfunction. These findings demonstrate that the endothelial dysfunction occurring in type 2 diabetes is the result of the effects of the inflammatory cytokine TNF-alpha and TNF-alpha-related signaling, including the expression of MCP-1 and adhesion molecules, which further exacerbates vessel inflammation and oxidative stress.

Chemokine signaling and the management of neuropathic pain.

Chemokines and chemokine receptors are widely expressed in the nervous system, where they play roles in the regulation of stem cell migration, axonal path finding, and neurotransmission. Chemokine signaling is also of key importance in the regulation of neuroinflammatory responses. The expression of the chemokine monocyte chemoattractant protein 1 (MCP1) and its receptor (CCR2) is upregulated by dorsal root ganglia neurons in rodent models of neuropathic pain. MCP1 increases the excitability of nociceptive neurons after a peripheral nerve injury, and disruption of MCP1 signaling blocks the development of neuropathic pain. In the spinal cord, microglial cells expressing CCR2 are thought to play an active role in the initiation and maintenance of pain hypersensitivity, and MCP1 may also alter the excitability of spinal neurons in some cases. Other predominant sites of CCR2 activation are found in the peripheral nervous system, thereby explaining, at least in some circumstances, the rapid anti-nociceptive effects of peripherally administered CCR2 antagonists. In this article we discuss the relative roles of CCR2 activation in the peripheral and central nervous systems in relation to the phenomenon of neuropathic pain.

Monocyte chemoattractant protein-1: A key mediator in inflammatory processes

Monocyte chemoattractant protein-1 (MCP-1) is a potent chemoattractant for monocytes and macrophages to areas of inflammation. MCP-1 is a prototypical chemokine subject to coordinated regulation by immunomodulatory agents. Since MCP-1 is implicated in multiple inflammatory diseases, it is a potential target for the treatment of these disorders. In this review, we will provide background information and summarize the MCP-1 structure and signaling pathways. Its involvement in multiple diseases, such as tumour development, atherogenesis and rare autoimmune diseases is also revised.

Abstract 243: Roles of TNF alpha and MCP-1 in Type II Diabetes-induced Endothelial Dysfunction

Tumor necrosis factor alpha (TNF) is reported to underlie a component of vascular inflammation and ensuing endothelial dysfunction in diabetes, but the role of inflammatory cells in these events is unknown. Because TNF reportedly induces monocyte chemoattractant protein-1 (MCP-1) expression, we hypothesized that the interaction between TNF and MCP-1 contributes to the evolution of vascular inflammation in diabetes. To test this hypothesis, expression of TNF and MCP-1, and formation of nitrotyrosine (N-Tyr, an indicator of peroxynitrite production) were determined in isolated coronary arterioles (50–100um) from genetically modified mice with Type II diabetes (Lepr db ) and the lean control heterozygotes (m Lepr db ). Protein and mRNA expression of TNF, protein expression of MCP-1, and presence of N-Tyr were significantly increased in arterioles from Lepr db mice compared to those from m Lepr db . Immunofluorescence double labeling revealed the prominent localization of MCP-1 to endothelium (Von Willebrand factor) of arterioles and venules. MCP-1 also co-localized with macrophages (CD68) in the heart tissue. To determine if MCP-1 may be key to the vascular inflammation and ensuing endothelial dysfunction, we administered anti-MCP-1 (10 μg/day, 3 days, i.p., n=4; to block MCP-1 signaling) in the mice and then determined endothelial dilation in isolated, cannulated pressurized (60 cmH2O) arterioles. Anti-MCP-1 restored dilation to acetylcholine in Lepr db mice by 35±2% (P&lt;0.05 vs Lepr db mice without treatment, 9.8±4%) but did not affect dilation in m Lepr db mice. To establish interactions between TNF and MCP-1, we administered anti-TNF (72hr treatment; 0.625mg/kg, i.p.) to block TNF signaling and determined effects on MCP-1 and oxidative stress. After anti-TNF administration, expression of MCP-1 was decreased and numbers of MCP-1 positive cells were markedly reduced in Lepr db mice. Moreover, anti-TNF prevented the formation of N-Tyr in Lepr db mice. These findings demonstrate that the endothelial dysfunction occurring in type II diabetes is the result of the effects of the inflammatory cytokine TNF and TNF related signaling, including the expression of MCP-1, which also furthers the oxidative stress.