Monocyte Chemoattractant Protein-1 Secretion Research Articles

Tangeretin inhibits airway inflammatory responses by reducing early growth response 1 (EGR1) expression in mice exposed to cigarette smoke and lipopolysaccharide

BackgroundTangeretin, a natural polymethoxyflavone compound, possesses potent anti-inflammatory activity that improves respiratory inflammation in chronic obstructive pulmonary disease (COPD). However, the molecular mechanisms underlying the anti-COPD effects of tangeretin remain unclear. In this study, we aimed to investigate the key molecular mechanisms by which tangeretin suppresses COPD-related inflammatory responses. MethodsWe conducted the investigation in phorbol-12-myristate-13-acetate (PMA)-stimulated human airway epithelial cells (in vitro) and cigarette smoke (CS)/lipopolysaccharide (LPS)-exposed mice (in vivo). ResultsTangeretin decreased the release of inflammatory mediators, including tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), and mucin 5AC (MUC5AC), by suppressing early growth response 1 (EGR1) expression in vitro. Tangeretin and EGR1 small interfering ribonucleic acid (siRNA) combination showed a synergistic reduction in MUC5AC and TNF-α secretion. Tangeretin administration significantly inhibited the levels of reactive oxygen species (ROS) production, elastase activity, TNF-α, IL-6, and monocyte chemoattractant protein-1 (MCP-1) secretion, and macrophage and neutrophil numbers in the bronchoalveolar lavage fluid of CS/LPS-exposed mice. Tangeretin also prevented CS/LPS-induced abnormal pathological changes and excessive MUC5AC and EGR1 expression in lung tissue. ConclusionComprehensively, tangeretin inhibits the lung inflammatory response associated with COPD by reducing EGR1 expression in PMA-induced human epithelial cells and in a CS/LPS-stimulated mouse model. This study shows that tangeretin has anti-COPD properties and can be a promising alternative (or complementary) treatment for inflammatory lung disease.

Branched-chain amino acids supplementation induces insulin resistance and pro-inflammatory macrophage polarization via INFGR1/JAK1/STAT1 signal pathway

BackgroundObesity is a global epidemic, and the low-grade chronic inflammation of adipose tissue in obese individuals can lead to insulin resistance and type 2 diabetes. Adipose tissue macrophages (ATMs) are the main source of pro-inflammatory cytokines in adipose tissue, making them an important target for therapy. While branched-chain amino acids (BCAA) have been strongly linked to obesity and type 2 diabetes in humans, the relationship between BCAA catabolism and adipose tissue inflammation is unclear. This study aims to investigate whether disrupted BCAA catabolism influences the function of adipose tissue macrophages and the secretion of pro-inflammatory cytokines in adipose tissue, and to determine the underlying mechanism. This research will help us better understand the role of BCAA catabolism in adipose tissue inflammation, obesity, and type 2 diabetes.MethodsIn vivo, we examined whether the BCAA catabolism in ATMs was altered in high-fat diet-induced obesity mice, and if BCAA supplementation would influence obesity, glucose tolerance, insulin sensitivity, adipose tissue inflammation and ATMs polarization in mice. In vitro, we isolated ATMs from standard chow and high BCAA-fed group mice, using RNA-sequencing to investigate the potential molecular pathway regulated by BCAA accumulation. Finally, we performed targeted gene silence experiment and used immunoblotting assays to verify our findings.ResultsWe found that BCAA catabolic enzymes in ATMs were influenced by high-fat diet induced obesity mice, which caused the accumulation of both BCAA and its downstream BCKA. BCAA supplementation will cause obesity and insulin resistance compared to standard chow (STC) group. And high BCAA diet will induce pro-inflammatory cytokines including Interlukin-1beta (IL-1β), Tumor Necrosis Factor alpha (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) secretion in adipose tissue as well as promoting ATMs M1 polarization (pro-inflammatory phenotype). Transcriptomic analysis revealed that a high BCAA diet would activate IFNGR1/JAK1/STAT1 pathway, and IFNGR1 specific silence can abolish the effect of BCAA supplementation-induced inflammation and ATMs M1 polarization.ConclusionsThe obesity mice model reveals the catabolism of BCAA was disrupted which will cause the accumulation of BCAA, and high-level BCAA will promote ATMs M1 polarization and increase the pro-inflammatory cytokines in adipose tissue which will cause the insulin resistance in further. Therefore, reducing the circulating level of BCAA can be a therapeutic strategy in obesity and insulin resistance patients.

Glaucine inhibits hypoxia-induced angiogenesis and attenuates LPS-induced inflammation in human retinal pigment epithelial ARPE-19 cells

Glaucine is an aporphine alkaloid with anti-inflammatory, bronchodilator and anti-cancer activities. However, the effects of glaucine in the regulation of age-related macular degeneration (AMD) remain unclear. Herein, we aimed to investigate the anti-angiogenetic and anti-inflammatory effects of glaucine in ARPE-19 cells. ARPE-19 cells were treated with N-(methoxyoxoacetyl)-glycine, methyl ester (DMOG) and cobalt chloride (CoCl2) for induction of hypoxia, while lipopolysaccharide (LPS) treatment was used for elicitation of inflammatory response. Cell viability was analyzed using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. The expression of hypoxia-inducible factor (HIF-1α) and vascular endothelial growth factor (VEGF) were measured by Western blot. The secretion of VEGF, interleukin (IL)-6 and monocyte chemoattractant protein-1 (MCP-1) was detected using enzyme-linked immunosorbent assay (ELISA). Human umbilical vein endothelial cells (HUVECs) were used for tube formation analysis. Expression of HIF-1α and secretion of VEGF were significantly increased under DMOG and CoCl2 induction, whereas glaucine significantly attenuated both HIF-1α expression and VEGF secretion by DMOG- and CoCl2-induced ARPE-19 cells. In addition, glaucine suppressed the tube formation by DMOG- and CoCl2-induced HUVEC cells. Moreover, glaucine also attenuated the production of IL-6 and MCP-1 by LPS-induced ARPE-19 cells. This study indicated that glaucine exhibited anti-angiogenic and anti-inflammatory effects, suggesting that glaucine might have benefits for the treatment of AMD.

Inflammatory Response of Monocytes/Macrophages in Patients with Systemic Sclerosis.

Investigation of the inflammatory response of immune cells is a current focus of research on autoimmune disorders. The aim of this study was to evaluate the inflammatory status of monocytes/macrophages in systemic sclerosis (SSc). The study included 35 SSc and 25 healthy participants. The secretion of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), monocyte chemoattractant protein-1 (MCP-1), interleukin-8 (IL-8), interleukin-6 (IL-6) was measured by enzyme-linked immunosorbent assay (ELISA) in primary cultures of monocytes/macrophages after stimulation with lipopolysaccharide (LPS) on day 1 and on day 6 of incubation. Impaired tolerance of the immune response was characterized by increased secretion of the inflammatory mediators in response to restimulation. Basal secretion of all cytokines was significantly higher in SSc patients compared to healthy individuals. The secretion of TNF-α, IL-1β and IL-6 after the initial LPS stimulation, and secretion of IL-1β, MCP-1, IL-6, IL-8 after LPS restimulation, was significantly higher in the SSc group. Eleven SSc patients (31%) showed impaired immune tolerance in terms of MCP-1 secretion. These patients were significantly younger and had a higher level of anti-topoisomerase I (anti-Scl70) antibodies compared to SSc patients with immune tolerance. This study revealed pro-inflammatory activation and impaired immune tolerance in monocytes/macrophages from SSc patients. The violation of immune response in terms of MCP-1 secretion may be an important factor in the development of chronic inflammation in SSc. MCP-1 may thus be a potential therapeutic target for novel SSc treatment strategies.

Molecular incompatibility between pig CD200 and human CD200 receptor in in vitro xenogeneic immune responses.

Overexpression of human CD200 (hCD200) in porcine endothelial cells (PECs) has been reported to suppress xenogeneic immune responses of human macrophages againstporcine endothelial cells. The current study aimed to address whether the above-mentioned beneficial effect of hCD200 is mediated by overcoming the molecular incompatibility between porcine CD200 (pCD200) and hCD200 receptor or simply by increasing the expression levels of CD200 without any molecular incompatibility across the two species. We overexpressed hCD200 or pCD200 using lentiviral vectors with V5 marker in porcine endothelial cells and compared their suppressive activity against U937-derived human macrophage-like cells (hMCs) and primary macrophages. In xenogeneic coculture of porcine endothelial cellsand human macrophage-like cells or macrophages, hCD200-porcine endothelial cells suppressed phagocytosis and cytotoxicity of human macrophages to a greater extent than pCD200-porcine endothelial cells. Secretion of tumor necrosis factor-α, interleukin-1β, and monocyte chemoattractant protein-1 from human macrophages and expression of M1 phenotypes (inducible nitric oxide synthase, dectin-1, and CD86) were also suppressed by hCD200 to a greater extent than pCD200. Furthermore, in signal transduction downstream of CD200 receptor, hCD200 induced Dok2 phosphorylation and suppressed IκB phosphorylation to a greater extent than pCD200. The above data supported the possibility of a significant molecular incompatibility between pCD200 and human CD200 receptor, suggesting that the beneficial effects of hCD200 overexpression in porcine endothelial cellscould be mediated by overcoming the molecular incompatibility across the species barrier rather than by simple overexpression effects of CD200.

Human-induced pluripotent stem cell-derived neural stem cell exosomes improve blood-brain barrier function after intracerebral hemorrhage by activating astrocytes via PI3K/AKT/MCP-1 axis.

JOURNAL/nrgr/04.03/01300535-202502000-00029/figure1/v/2024-05-28T214302Z/r/image-tiff Cerebral edema caused by blood-brain barrier injury after intracerebral hemorrhage is an important factor leading to poor prognosis. Human-induced pluripotent stem cell-derived neural stem cell exosomes (hiPSC-NSC-Exos) have shown potential for brain injury repair in central nervous system diseases. In this study, we explored the impact of hiPSC-NSC-Exos on blood-brain barrier preservation and the underlying mechanism. Our results indicated that intranasal delivery of hiPSC-NSC-Exos mitigated neurological deficits, enhanced blood-brain barrier integrity, and reduced leukocyte infiltration in a mouse model of intracerebral hemorrhage. Additionally, hiPSC-NSC-Exos decreased immune cell infiltration, activated astrocytes, and decreased the secretion of inflammatory cytokines like monocyte chemoattractant protein-1, macrophage inflammatory protein-1α, and tumor necrosis factor-α post-intracerebral hemorrhage, thereby improving the inflammatory microenvironment. RNA sequencing indicated that hiPSC-NSC-Exo activated the PI3K/AKT signaling pathway in astrocytes and decreased monocyte chemoattractant protein-1 secretion, thereby improving blood-brain barrier integrity. Treatment with the PI3K/AKT inhibitor LY294002 or the monocyte chemoattractant protein-1 neutralizing agent C1142 abolished these effects. In summary, our findings suggest that hiPSC-NSC-Exos maintains blood-brain barrier integrity, in part by downregulating monocyte chemoattractant protein-1 secretion through activation of the PI3K/AKT signaling pathway in astrocytes.

Modelling neurodegeneration and inflammation in early diabetic retinopathy using 3D human retinal organoids

PurposeDiabetic retinopathy (DR) is a complication of diabetes and a primary cause of visual impairment amongst working-age individuals. DR is a degenerative condition in which hyperglycaemia results in morphological and functional changes in certain retinal cells. Existing treatments mainly address the advanced stages of the disease, which involve vascular defects or neovascularization. However, it is now known that retinal neurodegeneration and inflammation precede these vascular changes as early events of DR. Therefore, there is a pressing need to develop a reliable human in vitro model that mimics the early stage of DR to identify new therapeutic approaches to prevent and delay its progression.MethodsHere, we used human-induced pluripotent stem cells (hiPSCs) differentiated into three-dimensional (3D) retinal organoids, which resemble the complexity of the retinal tissue. Retinal organoids were subjected to high-glucose conditions to generate a model of early DR.ResultsOur model showed well-established molecular and cellular features of early DR, such as (i) loss of retinal ganglion and amacrine cells; (ii) glial reactivity and inflammation, with increased expression of the vascular endothelial-derived growth factor (VEGF) and interleukin-1β (IL-1β), and monocyte chemoattractant protein-1 (MCP-1) secretion; and (iii) increased levels of reactive oxygen species accompanied by activation of key enzymes involved in antioxidative stress response.ConclusionThe data provided highlight the utility of retinal organoid technology in modelling early-stage DR. This offers new avenues for the development of targeted therapeutic interventions on neurodegeneration and inflammation in the initial phase of DR, potentially slowing the disease’s progression.

The influence of diet therapy and regular physical trainings on monocyte chemoattractant protein-1 (MCP-1) secretion by monocytes among obese patients with coronary heart disease

Chronic systemic inflammation is one of the leading pathogenetic pathways for the development of atherosclerosis in obese patients. In this regard, it seems promising to evaluate the effect of the diet and physical exertion on the proinflammatory activity of monocytes. The purpose of this research was to evaluate the effect of the diet and regular physical trainings on the secretion of monocyte chemotactic factor 1 (MCP-1) by monocytes in obese patients with coronary artery disease. Material and methods. 27 obese participants (body mass index >30 kg/m2) with a confirmed diagnosis of coronary heart disease were recruited. All participants were prescribed with 12 weeks of a specialized diet with a restriction of simple carbohydrates and salt, a 500-kcal daily energy deficit, and with inclusion of cruciferous (200 g per day), seasonal dark berries (70 g per day) and green tea (200 ml per day). The regular assisted physical trainings were also administered. The body composition, blood biochemical parameters and MCP-1 secretion rates in the primary culture of monocytes isolated from blood samples via the immunomagnetic separation method were assessed before and after the intervention. Results. As a result, after the 12-weeks intervention the reliable body weight loss (-4.0%), waist circumference (-4.2%), visceral fat (-5.4%), total cholesterol (-9.8%), LDL-cholesterol (-16.6%) and triglycerides (-26.0%), an improvement in the results of the 6-minute walk test (+10.33%) was achieved, as well as an LPS-stimulated monocytes secretion of MCP-1 decreased by 2.8 times (p=0.005). Conclusion. Overall, the results suggest that diet and regular physical activity in patients with obesity and coronary heart disease may decrease the functional "proinflammatory" activity of monocytes.

The BET inhibitor apabetalone decreases neuroendothelial proinflammatory activation in vitro and in a mouse model of systemic inflammation.

Brain vascular inflammation is characterized by endothelial activation and immune cell recruitment to the blood vessel wall, potentially causing a breach in the blood - brain barrier, brain parenchyma inflammation, and a decline of cognitive function. The clinical-stage small molecule, apabetalone, reduces circulating vascular endothelial inflammation markers and improves cognitive scores in elderly patients by targeting epigenetic regulators of gene transcription, bromodomain and extraterminal proteins. However, the effect of apabetalone on cytokine-activated brain vascular endothelial cells (BMVECs) is unknown. Here, we show that apabetalone treatment of BMVECs reduces hallmarks of in vitro endothelial activation, including monocyte chemoattractant protein-1 (MCP-1) and RANTES chemokine secretion, cell surface expression of endothelial cell adhesion molecule VCAM-1, as well as endothelial capture of THP-1 monocytes in static and shear stress conditions. Apabetalone pretreatment of THP-1 downregulates cell surface expression of chemokine receptors CCR1, CCR2, and CCR5, and of the VCAM-1 cognate receptor, integrin α4. Consequently, apabetalone reduces THP-1 chemoattraction towards soluble CCR ligands MCP-1 and RANTES, and THP-1 adhesion to activated BMVECs. In a mouse model of brain inflammation, apabetalone counters lipopolysaccharide-induced transcription of endothelial and myeloid cell markers, consistent with decreased neuroendothelial inflammation. In conclusion, apabetalone decreases proinflammatory activation of brain endothelial cells and monocytes in vitro and in the mouse brain during systemic inflammation.

Anti-inflammatory effects of neuregulin-1 in HaCaT keratinocytes and atopic dermatitis-like mice stimulated with Der p 38

Neuregulin (NRG)-1 plays fundamental roles in several organ systems after binding to its receptors, ErbB2 and ErbB4. This study examines the role of NRG-1 in atopic dermatitis (AD), a chronic skin disease that causes dryness, pruritus, and inflammation. In mice administered Der p 38, the skin presents AD-like symptoms including filaggrin downregulation and infiltration of neutrophils and eosinophils. Noticeably, there is an increased expression of NRG-1, ErbB2, and ErbB4 in the skin. Upregulation of these proteins is significantly correlated to the clinical skin severity score. In human keratinocyte HaCaT cells, exposure to Der p 38 decreased filaggrin expression, and NRG-1 alone had no effect on the expression. However, co-treatment of Der p 38 with NRG-1 enhanced the filaggrin expression decreased by Der p 38. Pre-treatment with AG879 (an ErbB2 inhibitor) or ErbB4 siRNA blocked the recovery of filaggrin expression in the cells after co-treatment with Der p 38 and NRG-1. Der p 38 treatment enhanced the secretion of interleukin-6 (IL-6), IL-8, and monocyte chemoattractant protein-1 (MCP-1). Co-treatment of Der p 38 with NRG-1 lowered the cytokine secretion increased by Der p 38, although NRG-1 alone was not effective on cytokine alteration. Neutrophil apoptosis was not altered by NRG-1 or supernatants of cells treated with NRG-1, but the cell supernatants co-treated with Der p 38 and NRG-1 blocked the anti-apoptotic effects of Der p 38-treated supernatants on neutrophils, which was involved in the activation of caspase 9 and caspase 3. Taken together, we determined that NRG-1 has anti-inflammatory effects in AD triggered by Der p 38. These results will pave the way to understanding the functions of NRG-1 and in the future development of AD treatment.

Syphilis and the host: multi-omic analysis of host cellular responses to Treponema pallidum provides novel insight into syphilis pathogenesis.

Syphilis is a chronic, multi-stage infection caused by the extracellular bacterium Treponema pallidum ssp. pallidum. Treponema pallidum widely disseminates through the vasculature, crosses endothelial, blood-brain and placental barriers, and establishes systemic infection. Although the capacity of T. pallidum to traverse the endothelium is well-described, the response of endothelial cells to T. pallidum exposure, and the contribution of this response to treponemal traversal, is poorly understood. To address this knowledge gap, we used quantitative proteomics and cytokine profiling to characterize endothelial responses to T. pallidum. Proteomic analyses detected altered host pathways controlling extracellular matrix organization, necroptosis and cell death, and innate immune signaling. Cytokine analyses of endothelial cells exposed to T. pallidum revealed increased secretion of interleukin (IL)-6, IL-8, and vascular endothelial growth factor (VEGF), and decreased secretion of monocyte chemoattractant protein-1 (MCP-1). This study provides insight into the molecular basis of syphilis disease symptoms and the enhanced susceptibility of individuals infected with syphilis to HIV co-infection. These investigations also enhance understanding of the host response to T. pallidum exposure and the pathogenic strategies used by T. pallidum to disseminate and persist within the host. Furthermore, our findings highlight the critical need for inclusion of appropriate controls when conducting T. pallidum-host cell interactions using in vitro- and in vivo-grown T. pallidum.

Novel piperazine-based ionizable lipid nanoparticles allow the repeated dose of mRNA to fibrotic lungs with improved potency and safety.

mRNA-based protein replacement therapy has received much attention as a novel intervention in clinical disease treatment. Lipid nanoparticles (LNPs) are widely used for their therapeutic potential to efficiently deliver mRNA. However, clinical translation has been hampered by the immunogenicity of LNPs that may aggravate underlying disease states. Here, we report a novel ionizable LNP with enhanced potency and safety. The piperazine-based biodegradable ionizable lipid (244cis) was developed for LNP formulation and its level of protein expression and immunogenicity in the target tissue was evaluated. It was found that 244cis LNP enabled substantial expression of the target protein (human erythropoietin), while it minimally induced the secretion of monocyte chemoattractant protein 1 (MCP-1) as compared to other conventional LNPs. Selective lung targeting of 244cis LNP was further investigated in tdTomato transgenic mice with bleomycin-induced pulmonary fibrosis (PF). The repeated administration of 244cis LNP with Cre recombinase mRNA achieved complete transfection of lung endothelial cells (~80%) and over 40% transfection of Sca-1-positive fibroblasts. It was shown that 244cis LNP allows the repeated dose of mRNA without the loss of activity due to its low immunogenicity. Our results demonstrate that 244cis LNP has great potential for the treatment of chronic diseases in the lungs with improved potency and safety.

The m6A methyltransferase METTL16 negatively regulates MCP1 expression in mesenchymal stem cells during monocyte recruitment.

Mesenchymal stem cells (MSCs) possess strong immunoregulatory functions, one aspect of which is recruiting monocytes from peripheral vessels to local tissue by secreting monocyte chemoattractant protein 1 (MCP1). However, the regulatory mechanisms of MCP1 secretion in MSCs are still unclear. Recently, the N6-methyladenosine (m6A) modification was reported to be involved in the functional regulation of MSCs. In this study, we demonstrated that methyltransferase-like 16 (METTL16) negatively regulated MCP1 expression in MSCs through the m6A modification. Specifically, the expression of METTL16 in MSCs decreased gradually and was negatively correlated with the expression of MCP1 after coculture with monocytes. Knocking down METTL16 markedly enhanced MCP1 expression and the ability to recruit monocytes. Mechanistically, knocking down METTL16 decreased MCP1 mRNA degradation, which was mediated by the m6A reader YTH N6-methyladenosine RNA-binding protein 2 (YTHDF2). We further revealed that YTHDF2 specifically recognized m6A sites on MCP1 mRNA in the CDS region and thus negatively regulated MCP1 expression. Moreover, an in vivo assay showed that MSCs transfected with METTL16 siRNA showed greater ability to recruit monocytes. These findings reveal a potential mechanism by which the m6A methylase METTL16 regulates MCP1 expression through YTHDF2-mediated mRNA degradation and suggest a potential strategy to manipulate MCP1 expression in MSCs.

Serratiopeptidase Attenuates Lipopolysaccharide-Induced Vascular Inflammation by Inhibiting the Expression of Monocyte Chemoattractant Protein-1.

Lipopolysaccharide (LPS) has potent pro-inflammatory properties and acts on many cell types including vascular endothelial cells. The secretion of the cytokines MCP-1 (CCL2), interleukins, and the elevation of oxidative stress by LPS-activated vascular endothelial cells contribute substantially to the pathogenesis of vascular inflammation. However, the mechanism involving LPS-induced MCP-1, interleukins, and oxidative stress together is not well demonstrated. Serratiopeptidase (SRP) has been widely used for its anti-inflammatory effects. In this research study, our intention is to establish a potential drug candidate for vascular inflammation in cardiovascular disorder conditions. We used BALB/c mice because this is the most successful model of vascular inflammation, suggested and validated by previous research findings. Our present investigation examined the involvement of SRP in vascular inflammation caused by lipopolysaccharides (LPSs) in a BALB/c mice model. We analyzed the inflammation and changes in the aorta by H&E staining. SOD, MDA, and GPx levels were determined as per the instructions of the kit protocols. ELISA was used to measure the levels of interleukins, whereas immunohistochemistry was carried out for the evaluation of MCP-1 expression. SRP treatment significantly suppressed vascular inflammation in BALB/c mice. Mechanistic studies demonstrated that SRP significantly inhibited the LPS-induced production of proinflammatory cytokines such as IL-2, IL-1, IL-6, and TNF-α in aortic tissue. Furthermore, it also inhibited LPS-induced oxidative stress in the aortas of mice, whereas the expression and activity of monocyte chemoattractant protein-1 (MCP-1) decreased after SRP treatment. In conclusion, SRP has the ability to reduce LPS-induced vascular inflammation and damage by modulating MCP-1.

Notch-mediated hepatocyte MCP-1 secretion causes liver fibrosis.

Patients with nonalcoholic steatohepatitis (NASH) have increased expression of liver monocyte chemoattractant protein-1 (MCP-1), but its cellular source and contribution to various aspects of NASH pathophysiology remain debated. We demonstrated increased liver CCL2 (which encodes MCP-1) expression in patients with NASH, and commensurately, a 100-fold increase in hepatocyte Ccl2 expression in a mouse model of NASH, accompanied by increased liver monocyte-derived macrophage (MoMF) infiltrate and liver fibrosis. To test repercussions of increased hepatocyte-derived MCP-1, we generated hepatocyte-specific Ccl2-knockout mice, which showed reduced liver MoMF infiltrate as well as decreased liver fibrosis. Forced hepatocyte MCP-1 expression provoked the opposite phenotype in chow-fed wild-type mice. Consistent with increased hepatocyte Notch signaling in NASH, we observed a close correlation between markers of Notch activation and CCL2 expression in patients with NASH. We found that an evolutionarily conserved Notch/recombination signal binding protein for immunoglobulin kappa J region binding site in the Ccl2 promoter mediated transactivation of the Ccl2 promoter in NASH diet-fed mice. Increased liver MoMF infiltrate and liver fibrosis seen in opposite gain-of-function mice was ameliorated with concomitant hepatocyte Ccl2 knockout or CCR2 inhibitor treatment. Hepatocyte Notch activation prompts MCP-1-dependent increase in liver MoMF infiltration and fibrosis.

Vascular smooth muscle cell mechanotransduction through serum and glucocorticoid inducible kinase-1 promotes interleukin-6 production and macrophage accumulation in murine hypertension

ObjectiveThe objective of this investigation was to demonstrate that in vivo induction of hypertension (HTN) and in vitro cyclic stretch of aortic vascular smooth muscle cells (VSMCs) can cause serum and glucocorticoid-inducible kinase (SGK-1)-dependent production of cytokines to promote macrophage accumulation that may promote vascular pathology. MethodsHTN was induced in C57Bl/6 mice with angiotensin II infusion (1.46 mg/kg/day × 21 days) with or without systemic infusion of EMD638683 (2.5 mg/kg/day × 21 days), a selective SGK-1 inhibitor. Systolic blood pressure was recorded. Abdominal aortas were harvested to quantify SGK-1 activity (pSGK-1/SGK-1) by immunoblot. Flow cytometry quantified the abundance of CD11b+/F480+ cells (macrophages). Plasma interleukin (IL)-6 and monocyte chemoattractant protein-1 (MCP-1) was assessed by enzyme-linked immunosorbent assay. Aortic VSMCs from wild-type mice were subjected to 12% biaxial cyclic stretch (Stretch) for 3 or 12 hours with or without EMD638683 (10 μM) and with or without SGK-1 small interfering RNA with subsequent quantitative polymerase chain reaction for IL-6 and MCP-1 expression. IL-6 and MCP-1 in culture media were analyzed by enzyme-linked immunosorbent assay. Aortic VSMCs from SGK-1flox+/+ mice were transfected with Cre-Adenovirus to knockdown SGK-1 (SGK-1KD VSMCs) and underwent parallel tension experimentation. Computational modeling was used to simulate VSMC signaling. Statistical analysis included analysis of variance with significance at a P value of <.05. ResultsSGK-1 activity, abundance of CD11b+/F4-80+ cells, and plasma IL-6 were increased in the abdominal aorta of mice with HTN and significantly reduced by treatment with EMD638683. This outcome mirrored the increased abundance of IL-6 in media from Stretch C57Bl/6 VSMCs and attenuation of the effect with EMD638683 or SGK-1 small interfering RNA. C57Bl/6 VSMCs also responded to Stretch with increased MCP-1 expression and secretion into the culture media. Further supporting the integral role of mechanical signaling through SGK-1, target gene expression and cytokine secretion was unchanged in SGK-1KD VSMCs with Stretch, and computer modeling confirmed SGK-1 as an intersecting node of signaling owing to mechanical strain and angiotensin II. ConclusionsMechanical activation of SGK-1 in aortic VSMCs can promote inflammatory signaling and increased macrophage abundance, therefore this kinase warrants further exploration as a pharmacotherapeutic target to abrogate hypertensive vascular pathology.

MCP-1/CCR2 axis inhibition sensitizes the brain microenvironment against melanoma brain metastasis progression.

Development of resistance to chemo- and immunotherapies often occurs following treatment of melanoma brain metastasis (MBM). The brain microenvironment (BME), particularly astrocytes, cooperate toward MBM progression by upregulating secreted factors, among which we found that monocyte chemoattractant protein-1 (MCP-1) and its receptors, CCR2 and CCR4, were overexpressed in MBM compared with primary lesions. Among other sources of MCP-1 in the brain, we show that melanoma cells altered astrocyte secretome and evoked MCP-1 expression and secretion, which in turn induced CCR2 expression in melanoma cells, enhancing in vitro tumorigenic properties, such as proliferation, migration, and invasion of melanoma cells. In vivo pharmacological blockade of MCP-1 or molecular knockout of CCR2/CCR4 increased the infiltration of cytotoxic CD8+ T cells and attenuated the immunosuppressive phenotype of the BME as shown by decreased infiltration of Tregs and tumor-associated macrophages/microglia in several models of intracranially injected MBM. These in vivo strategies led to decreased MBM outgrowth and prolonged the overall survival of the mice. Our findings highlight the therapeutic potential of inhibiting interactions between BME and melanoma cells for the treatment of this disease.

1,25-dihydroxyvitamin D3 ameliorates high glucose-mediated proliferation, migration, and MCP-1 secretion of vascular smooth muscle cells by inhibiting MAPK phosphorylation

ObjectivesTo explore the impacts of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on the proliferation, migration, and monocyte chemoattractant protein-1 (MCP-1) secretion of vascular smooth muscle cells (VSMCs) in a high glucose environment and its possible mechanism.MethodsWe extracted VSMCs from the thoracic aorta of a male Sprague–Dawley rats before culturing them in a 25-mM glucose-containing medium in the presence or absence of 1,25(OH)2D3 (10−9 –10−7 M). Cell proliferation was determined by bromodeoxyuridine incorporation assays. Subsequently, cell migratory capacity was examined by performing a transwell assay. An enzyme-linked immunosorbent assay was conducted to assess MCP-1 levels. Protein levels of matrix metalloproteinase-9 (MMP-9), mitogen-activated protein kinases (MAPKs), cyclin D1, and phosphorylated MAPKs were determined by immunoblotting.Results1,25(OH)2D3 significantly suppressed the proliferation, migration, and MCP-1 secretion of VSMCs mediated by high glucose in a dose-dependent manner, diminished the enhanced protein expression of MMP-9 and cyclin D1, and attenuated MAPK phosphorylation. The p38 inhibitor SB203580 and ERK1/2 inhibitor PD98059 suppressed high glucose-mediated upregulation of MMP-9 and cyclin D1 protein expression and MCP-1 secretion, respectively.Conclusions1,25(OH)2D3 ameliorates high glucose-mediated proliferation, migration, and MCP-1 secretion of VSMCs by inhibiting MAPK phosphorylation, implying a potential therapeutic approach using 1,25(OH)2D3 for diabetic macrovascular complications.

Regulation of vascular endothelial cell activator expression by tanshinone Ⅱ_A based on PI3K/Akt signaling pathway

The present study investigated the regulatory effect of tanshinone Ⅱ_A(TAⅡ_A) on activator expression in human umbilical vein endothelial cells(HUVECs) and the effect on the phosphoinositide 3-kinase(PI3 K)/protein kinase B(Akt) signaling pathway in patients with antiphospholipid syndrome(APS). HUVECs cultured in vitro were divided into a medium group, a blank control group, an APS model group, an APS+LY5 group, an APS+LY10 group, an APS+LY20 group, an APS+TAⅡ_A5 group, an APS+TAⅡ_A10 group, an APS+TAⅡ_A20 group, and an APS+TAⅡ_A10+LY10 group. The effects of LY294002 and TAⅡ_A at different concentrations on the secretion of interleukin-6(IL-6), interleukin-8(IL-8), and monocyte chemoattractant protein-1(MCP-1) by HUVECs were investigated. The effects on the mRNA expression of annexin A2(ANXA2), PI3 K, Akt, and E-cadherin(E-cad) were detected by quantitative polymerase chain reaction(qPCR), and Western blot was used to determine the effects on the protein expression of ANXA2, p-PI3 K/PI3 K, p-Akt/Akt, and E-cad. The results revealed that compared with the APS model group, the APS+TAⅡ_A10 group showed statistically reduced IL-6 and MCP-1 and increased IL-8 in a concentration-dependent manner with the increase in TAⅡ_A dose, while the APS+TAⅡ_A10 group showed increased mRNA and protein expression of ANXA2, PI3 K, Akt, and E-cad(P&lt;0.05 or P&lt;0.01) in a concentration-dependent manner with the increase in TAⅡ_A dose. The findings indicated that the serum of APS patients could lead to the decreased mRNA and protein expression levels of ANXA2, PI3 K, Akt, and E-cad in HUVECs, increased secretion of IL-6 and MCP-1, and reduced secretion of IL-8, and activate vascular endothelial cells. In contrast, once the PI3 K/Akt signaling pathway was blocked, the mRNA and protein expression of ANXA2 and E-cad significantly decreased, IL-6 and MCP-1 secretion significantly increased, and IL-8 secretion was significantly reduced. It suggests that TAⅡ_A regulates the activation of vascular endothelial cells in APS patients by activating the PI3 K/Akt signaling pathway.

Extracellular Cardiolipin Modulates Select Immune Functions of Astrocytes in Toll-Like Receptor (TLR) 4-Dependent Manner.

Alzheimer's disease (AD) is characterized by chronic neuroinflammation, which is partially mediated by dysregulated functions of glial cells. Cardiolipin (CL) is a phospholipid normally confined to the inner mitochondrial membrane; however, it has been detected in human sera, indicating that it can exist in the extracellular space where it may interact with nearby cells. Although CL has been shown to modulate several functions of microglia in a toll-like receptor (TLR) 4-dependent manner, the effects of extracellular CL on astrocytes are unknown. In addition to their homeostatic functions, astrocytes participate in neuroimmune responses of the brain and express TLR 4. Therefore, we hypothesized that extracellular CL (1) modulates the secretion of cytokines and cytotoxins by astrocytes, as well as their phagocytic activity, and (2) acts by interacting with astrocyte TLR 4. We demonstrate that CL inhibits the lipopolysaccharide- (LPS-) induced secretion of cytotoxins and expression of glial fibrillary acidic protein (GFAP) by human U118 MG astrocytic cells. CL alone upregulates the phagocytic activity of human astrocytic cells and primary murine astrocytes. CL in combination with LPS upregulates secretion of interleukin (IL)-1β by astrocytic cells. Furthermore, CL alone increases the secretion of monocyte chemoattractant protein (MCP)-1 by astrocytic cells, which is blocked by the TLR 4-specific antagonist TAK-242. We demonstrate that CL upregulates MCP-1 secretion in the absence of its natural carrier protein, β2-glycoprotein 1, indicating that CL may be bioactive in the brain where this protein is not present. Lastly, we show that CL downregulates the expression of astrocytic TLR 4, implying that CL engages this receptor, as its activation has been shown to lead to its degradation. Overall, our study extends the list of cell type functions of which CL modulates and provides evidence that CL, or liposomes containing this phospholipid can be used to modulate specific neuroimmune functions of astrocytes.