-
1.
Human monocyte transcriptional profiling identifies IL-18 receptor accessory protein and lactoferrin as novel immune targets in hypertension.
Alexander, MR, Norlander, AE, Elijovich, F, Atreya, RV, Gaye, A, Gnecco, JS, Laffer, CL, Galindo, CL, Madhur, MS
British journal of pharmacology. 2019;(12):2015-2027
-
-
Free full text
-
Abstract
BACKGROUND AND PURPOSE Monocytes play a critical role in hypertension. The purpose of our study was to use an unbiased approach to determine whether hypertensive individuals on conventional therapy exhibit an altered monocyte gene expression profile and to perform validation studies of selected genes to identify novel therapeutic targets for hypertension. EXPERIMENTAL APPROACH Next generation RNA sequencing identified differentially expressed genes in a small discovery cohort of normotensive and hypertensive individuals. Several of these genes were further investigated for association with hypertension in multiple validation cohorts using qRT-PCR, regression analysis, phenome-wide association study and case-control analysis of a missense polymorphism. KEY RESULTS We identified 60 genes that were significantly differentially expressed in hypertensive monocytes, many of which are related to IL-1β. Uni- and multivariate regression analyses of the expression of these genes with mean arterial pressure (MAP) revealed four genes that significantly correlated with MAP in normotensive and/or hypertensive individuals. Of these, lactoferrin (LTF), peptidoglycan recognition protein 1 and IL-18 receptor accessory protein (IL18RAP) remained significantly elevated in peripheral monocytes of hypertensive individuals in a separate validation cohort. Interestingly, IL18RAP expression associated with MAP in a cohort of African Americans. Furthermore, homozygosity for a missense single nucleotide polymorphism in LTF that decreases antimicrobial function and increases protein levels (rs1126478) was over-represented in patients with hypertension relative to controls (odds ratio 1.16). CONCLUSIONS AND IMPLICATIONS These data demonstrate that monocytes exhibit enhanced pro-inflammatory gene expression in hypertensive individuals and identify IL18RAP and LTF as potential novel mediators of human hypertension. LINKED ARTICLES This article is part of a themed section on Immune Targets in Hypertension. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.12/issuetoc.
-
2.
Inhibitors of DAG metabolism suppress CCR2 signalling in human monocytes.
Day, P, Burrows, L, Richards, D, Fountain, SJ
British journal of pharmacology. 2019;(15):2736-2749
-
-
Free full text
-
Abstract
BACKGROUND AND PURPOSE CCL2 is an inflammatory chemokine that stimulates the recruitment of monocytes into tissue via activation of the GPCR CCR2. EXPERIMENTAL APPROACH Freshly isolated human monocytes and THP-1 cells were used. Fura-2 loaded cells were used to measure intracellular Ca2+ responses. Transwell migration to measure chemotaxis. siRNA-mediated gene knock-down was used to support pharmacological approaches. KEY RESULTS CCL2 evoked intracellular Ca2+ signals and stimulated migration in THP-1 monocytic cells and human CD14+ monocytes in a CCR2-dependent fashion. Attenuation of DAG catabolism in monocytes by inhibiting DAG kinase (R59949) or DAG lipase (RHC80267) activity suppressed CCL2-evoked Ca2+ signalling and transwell migration in monocytes. These effects were not due to a reduction in the number of cell surface CCR2. The effect of inhibiting DAG kinase or DAG lipase could be mimicked by addition of the DAG analogue 1-oleoyl-2-acetyl-sn-glycerol (OAG) but was not rescued by application of exogenous phosphatidylinositol 4,5-bisphosphate. Suppressive effects of R59949, RHC80267, and OAG were partially or fully reversed by Gö6983 (pan PKC isoenzyme inhibitor) but not by Gö6976 (PKCα and PKCβ inhibitor). RNAi-mediated knock-down of DAG kinase α isoenzyme modulated CCL2-evoked Ca2+ responses in THP-1 cells. CONCLUSIONS AND IMPLICATIONS Taken together, these data suggest that DAG production resulting from CCR2 activation is metabolised by both DAG kinase and DAG lipase pathways in monocytes and that pharmacological inhibition of DAG catabolism or application suppresses signalling on the CCL2-CCR2 axis via a mechanism dependent upon a PKC isoenzyme that is sensitive to Gö6983 but not Gö6976.
-
3.
NF-κB-Dependent Production of ROS and Restriction of HSV-1 Infection in U937 Monocytic Cells.
Marino-Merlo, F, Papaianni, E, Frezza, C, Pedatella, S, De Nisco, M, Macchi, B, Grelli, S, Mastino, A
Viruses. 2019;(5)
Abstract
Herpes simplex virus 1 (HSV-1) can infect a wide range of cell types, including cells of the adaptive and innate immunity but, normally, it completes a fully-permissive replication cycle only in epithelial or neural cells. Complex mechanisms controlling this delicate balance in immune cells and consequent restriction of HSV-1 infection in these cells have not been completely elucidated. We have recently demonstrated that the transcription factor nuclear factor kappa B (NF-κB) can act as a main permissiveness regulator of HSV-1 infection in monocytic cells, however, mediators involved in this regulation have not been identified. To better define mechanisms involved in this phenomenon and, particularly, the possible involvement of ROS, wild type U937 cells or U937 cells stably transfected with a dominant-negative (DN) IκB-mutant and selenium-containing compounds, as anti-oxidants, were utilized. The main results can be summarized as follows. HSV-1 infection induces an immediate ROS production in U937 monocytic cells that can efficiently activate NF-κB but not in DN-IκB-mutant cells. Treatment with selenium-containing antioxidants efficiently inhibited HSV-1-induced ROS generation while producing increased levels of HSV-1 replication and a reduction of HSV-1-induced NF-κB activation in U937 monocytic cells. Our results suggest a scenario in which an efficient NF-κB-dependent ROS production in response to infection could contribute in limiting HSV-1 replication in monocytes/macrophages, thus avoiding possible irreparable damage to the innate immune system of the host during HSV-1 infection.
-
4.
Incorporation of dynamic segmented neutrophil-to-monocyte ratio with leukocyte count for sepsis risk stratification.
Fang, WF, Chen, YM, Wang, YH, Huang, CH, Hung, KY, Fang, YT, Chang, YC, Lin, CY, Chang, YT, Chen, HC, et al
Scientific reports. 2019;(1):19756
Abstract
The association between sepsis and segmented neutrophil-to-monocyte (SeMo) ratio is unclear. We postulated that an increase in dynamic SeMo ratio measurement can be applied in risk stratification. This retrospective study included 727 consecutive sepsis patients in medical intensive care units (ICUs), including a subpopulation of 153 patients. According to the leukocyte (white blood cell, WBC) count on day 3 (normal range, between 4,000/µL and 12,000/µL) and delta SeMo (value of SeMo ratio on day 3 minus value of SeMo ratio on day 1; normal delta SeMo, <7), patients were grouped into 3 (delta SeMo & WBC tool). The survival lines separated significantly with hazard ratios of 1.854 (1.342-2.560) for the delta SeMo or WBC abnormal group and 2.860 (1.849-4.439) for the delta SeMo and WBC abnormal group compared to the delta SeMo and WBC normal group. Delta SeMo & WBC tool and delta sequential organ failure assessment (SOFA) tool performed better than the other tools (delta SeMo, delta WBC, day 3 WBC, and day 1 WBC). Severity in delta SeMo & WBC tool and delta SeMo tool reflected the immune dysfunction score, cytokine expression, and human leukocyte antigen D-related monocyte expression on day 1 and day 3. There was correspondence between delta SOFA and delta WBC and between delta SeMo and delta cytokine expression. Incorporation of dynamic SeMo ratio with WBC count provides risk stratification for sepsis patients admitted in the ICU.
-
5.
Oral Ketone Supplementation Acutely Increases Markers of NLRP3 Inflammasome Activation in Human Monocytes.
Neudorf, H, Durrer, C, Myette-Cote, E, Makins, C, O'Malley, T, Little, JP
Molecular nutrition & food research. 2019;(11):e1801171
Abstract
SCOPE Cell culture studies indicate that the ketone β-hydroxybutyrate (β-OHB) directly inhibits the NLRP3 inflammasome, a key regulator of inflammation. However, direct evidence demonstrating this effect in humans is lacking. METHODS AND RESULTS To determine the effects of acutely raising blood β-OHB in healthy humans, two separate randomized double-blind placebo-controlled experiments are conducted using similar methods but each employed different exogenous ketone supplements. Participants' blood β-OHB is directly elevated by ketone salts (0.3 g β-OHB per kg; Study 1, N = 10 males) or ketone monoester (0.482 g β-OHB per kg; Study 2, N = 18, equal males/females). Markers of NLRP3 inflammasome activation include caspase-1, IL-1β secretion, and IL1B and NLRP3 mRNA in LPS-stimulated whole blood collected at the baseline and 30 minutes following supplementation. Caspase-1 activation increases after ketone salt (Study 1: condition × time interaction, p = 0.012) and monoester supplementation (Study 2: condition × time interaction, p = 0.016) compared to placebo. IL-1β secretion increases (main effect of condition, p = 0.024; Study 2) while IL1B and NLRP3 mRNA remain unchanged. CONCLUSION Measures of NLRP3 activation increases when blood β-OHB is elevated using ketone supplements, suggesting that increasing β-OHB exogenously may have unintended effects that augment inflammatory activation.
-
6.
Brief Report: Zinc Supplementation and Inflammation in Treated HIV.
Dirajlal-Fargo, S, Yu, J, Kulkarni, M, Sattar, A, Funderburg, N, Barkoukis, H, Mccomsey, GA
Journal of acquired immune deficiency syndromes (1999). 2019;(3):275-280
-
-
Free full text
-
Abstract
OBJECTIVE In this study, we explored the effect of zinc supplementation on markers of inflammation and monocyte activation in antiretroviral therapy-treated HIV infection. METHODS This is a phase I open-labeled randomized double-arm study, exploring the efficacy and safety of zinc supplementation on inflammation in ≥18-year-old people living with HIV in the US, on stable antiretroviral therapy and with zinc levels ≤75 µg/dL in the last 60 days. Patients were randomized 1:1 to zinc gluconate capsules at a dose of 45 mg (low-dose), or 90 mg (high-dose) elemental zinc daily for 16 weeks. We assessed inflammatory and gut integrity biomarkers at baseline and 16 weeks. RESULTS Overall, a total of 52 participants were enrolled (25 participants in the low-dose arm and 27 participants in the high-dose arm). Median (Interquartile range) age was 49 (38, 60) years, 77% were men and 73% were African Americans. At baseline, median zinc levels were 73 (64, 86) µg/dL. Median circulating zinc levels increased to 91 µg/dL in the low-dose arm and to 100 µg/dL in the high-dose arm. Overall, 48%-60% of participants experienced a reduction in biomarkers levels. The margin of reduction ranged between 8% and 21%. This change was meaningful with large effect size (Cohen D ranging from 5 to 19). CONCLUSIONS In this pilot study, we found that zinc supplementation is effective at increasing circulating zinc levels. In addition, our findings provide novel data suggesting that zinc can affect a biological signature in people living with HIV and modulate biomarkers associated with clinical comorbidities.
-
7.
A Growth Factor-Free Co-Culture System of Osteoblasts and Peripheral Blood Mononuclear Cells for the Evaluation of the Osteogenesis Potential of Melt-Electrowritten Polycaprolactone Scaffolds.
Hammerl, A, Diaz Cano, CE, De-Juan-Pardo, EM, van Griensven, M, Poh, PSP
International journal of molecular sciences. 2019;(5)
Abstract
Scaffolds made of biodegradable biomaterials are widely used to guide bone regeneration. Commonly, in vitro assessment of scaffolds' osteogenesis potential has been performed predominantly in monoculture settings. Hence, this study evaluated the potential of an unstimulated, growth factor-free co-culture system comprised of osteoblasts (OB) and peripheral blood mononuclear cells (PBMC) over monoculture of OB as an in vitro platform for screening of bone regeneration potential of scaffolds. Particularly, this study focuses on the osteogenic differentiation and mineralized matrix formation aspects of cells. The study was performed using scaffolds fabricated by means of a melt electrowriting (MEW) technique made of medical-grade polycaprolactone (PCL), with or without a surface coating of calcium phosphate (CaP). Qualitative results, i.e., cell morphology by fluorescence imaging and matrix mineralization by von Kossa staining, indicated the differences in cell behaviours in response to scaffolds' biomaterial. However, no obvious differences were noted between OB and OB+PBMC groups. Hence, quantitative investigation, i.e., alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP) activities, and gene expression were quantitatively evaluated by reverse transcription-polymerase chain reaction (RT-qPCR), were evaluated only of PCL/CaP scaffolds cultured with OB+PBMC, while PCL/CaP scaffolds cultured with OB or PBMC acted as a control. Although this study showed no differences in terms of osteogenic differentiation and ECM mineralization, preliminary qualitative results indicate an obvious difference in the cell/non-mineralized ECM density between scaffolds cultured with OB or OB+PBMC that could be worth further investigation. Collectively, the unstimulated, growth factor-free co-culture (OB+PBMC) system presented in this study could be beneficial for the pre-screening of scaffolds' in vitro bone regeneration potential prior to validation in vivo.
-
8.
Sex-specific association of monocyte count to high-density lipoprotein ratio with SYNTAX score in patients with suspected stable coronary artery disease.
Xu, W, Guan, H, Gao, D, Pan, J, Wang, Z, Alam, M, Lian, J, Zhou, J
Medicine. 2019;(41):e17536
-
-
Free full text
-
Abstract
Recently, the monocyte count to high-density lipoprotein cholesterol ratio (MHR) was found to be associated with the SYNTAX score in patients with both stable coronary artery disease (CAD) and acute coronary syndrome (ACS). The MHR was significantly higher in male patients. However, the sex-specific association of MHR with SYNTAX score in stable CAD was not well explored. Thus, the present study aimed to investigate the association of MHR and presence and severity of CAD evaluated by coronary angiography and the SYNTAX score in males and females.In total, 873 patients who received selective coronary angiography between March 2017 and July 2018 were included in the present study. Patients were divided into 3 groups according to MHR tertiles. The MHR was calculated by dividing the monocyte count by the high-density lipoprotein cholesterol level. CAD was defined as at least 50% diameter stenosis of a major coronary artery, including the right coronary, left main coronary, left anterior descending, and left circumflex arteries. The SYNTAX score was calculated by 2 experienced interventional cardiologists. SYNTAX score ≥23 was defined as a high SYNTAX score.Males showed a significantly higher MHR (12.2 [8.9-15.5] vs 9.3 [6.2-12.1], P < .001), accompanied by a higher prevalence of CAD (68.1% vs 53.4%, P < .001). Male sex remained an independent predictor of elevated MHR after correction for confounding factors (adjusted odds ratio [OR] 3.102, P = .001). The association between MHR and SYNTAX score was confirmed only in male stable patients with CAD (r = 0.113, P = .036). Multivariate logistic regression analysis showed that MHR was an independent predictor of SYNTAX score ≥23 only in male patients with CAD. The receiver-operating characteristic curve showed a predictive value of MHR for high SYNTAX score only in males.A higher MHR in males and a positive correlation of MHR with SYNTAX score were observed only in male stable patients with CAD. Such an easily obtained index may help interventional cardiologists detect high-risk patients before coronary catheterization, but its application may be restricted to males.
-
9.
Dry leaf extracts of Tinospora cordifolia (Willd.) Miers attenuate oxidative stress and inflammatory condition in human monocytic (THP-1) cells.
Reddi, KK, Tetali, SD
Phytomedicine : international journal of phytotherapy and phytopharmacology. 2019;:152831
Abstract
BACKGROUND Tinospora cordifolia (Willd.) Miers is known for its therapeutic value in Indian traditional medicine for treating diabetes, rheumatoid arthritis, jaundice and cardiac diseases. However, information regarding its protective role against inflammatory diseases at the molecular level is limited. PURPOSE The objective of the present work is to study the antioxidant and anti-inflammatory effect of alcoholic and water extracts of T. cordifolia (Willd.) Miers leaves in activated human monocytic THP-1 cells. STUDY DESIGN/METHODS Phytochemical analyses of the dry leaf extracts of T. cordifolia (Willd.) Miers prepared using the solvents alcohol (TCAE) or water (TCWE) are performed employing spectrophotometric methods for estimating total phenolic and flavonoid content, and the plant material was authenticated by detecting T. cordifolia (Willd.) Miers metabolite biomarkers using LC-MS/MS. Arachidonic acid (AA)- and lipopolysaccharide (LPS)-activated human monocytic (THP-1) cells were used as experimental models to investigate the antioxidant and anti-inflammatory activities of the plant extracts. Arachidonic acid (AA)-induced reactive oxygen species (ROS) in THP-1 cells were monitored by confocal microscopy/spectrofluorimetry and transcript of antioxidant enzyme catalase (CAT), by quantitative real time PCR. Lipopolysaccharide (LPS)-induced proinflammatory marker like TNF-α at transcription and protein levels in THP-1 cells were measured by quantitative real-time PCR or ELISA respectively. Further, the effect of T. cordifolia (Willd.) Miers extracts on LPS-induced NF-κB translocation, and IκB and P-IκB protein levels, were studied by immunoblotting and confocal microscopy. RESULTS T. cordifolia (Willd.) Miers extracts exhibited significant amounts of total phenolic and flavonoid content, and LC-MS/MS analyses detected tinosponone, a TC-specific clerodane-derived diterpene. Both types of extracts attenuated AA-induced ROS generation via enhancing catalase enzyme activity in THP-1 cells. Real time PCR and ELISA experiments revealed that the elevated levels of LPS-induced TNF-α was remarkably attenuated in THP-1 cells pretreated with T. cordifolia (Willd.) Miers extracts. Western blot and confocal microscopy showed that the alcoholic extract's anti-inflammatory activity by attenuating NF-κB translocation into the nucleus in LPS-activated THP-1 cells via the inhibition of IκB degradation in the cytosol. CONCLUSION Our findings suggest that T. cordifolia (Willd.) Miers dry leaf extracts possess antioxidant and anti-inflammatory properties via upregulation of antioxidant enzymes and attenuation of NF- κB nuclear translocation in activated human monocytic (THP-1) cells, therefore the present study supports our proposed molecular basis for the traditional use of T. cordifolia (Willd.) Miers for treating various inflammatory diseases.
-
10.
Secretion of IL-1β From Monocytes in Gout Is Redox Independent.
Alberts, BM, Bruce, C, Basnayake, K, Ghezzi, P, Davies, KA, Mullen, LM
Frontiers in immunology. 2019;:70
Abstract
The pro-inflammatory cytokine interleukin-1β (IL-1β) plays important roles in immunity but is also implicated in autoimmune disease. The most well-established mechanism of IL-1β secretion is via activation of the NOD-like receptor family pyrin domain containing-3 (NLRP3) inflammasome which requires an initial priming signal followed by an activating signal. However, the precise mechanism by which the inflammasome is activated remains unclear. The role of reactive oxygen species (ROS) in this process is contradictory, with some studies suggesting that ROS are crucial while others describe opposite effects. In this study, we evaluated the effects of oxidative stress on IL-1β secretion. Gout is a disease driven solely by IL-1β secretion in response to monosodium urate (MSU) crystals which form during periods of hyperuricemia and thus presents an opportunity to study factors contributing to IL-1β secretion. Sera and monocytes were isolated from patients with gout to determine whether differences in antioxidant status could explain the susceptibility of these individuals to gout attacks. In addition, sera and monocytes were collected from patients with chronic kidney disease (CKD) for comparison as this condition is associated with high levels of oxidative stress and disturbances in serum uric acid levels. There were differences in some aspects of antioxidant defenses in gout patients and these were mainly due to higher serum uric acid. Monocytes from gout patients were more responsive to priming, but not activation, of the NLRP3 inflammasome. However, expression of the components of the NLRP3 inflammasome were unaffected by priming or activation of the inflammasome, nor were these expression levels differentially regulated in gout patients. Inhibition of ROS by N-Acetyl Cysteine inhibited TLR2-induced priming of the NLRP3 inflammasome, but had no effect on MSU-induced activation. Together these findings demonstrate that oxidative stress only affects priming of the NLRP3 inflammasome but does not influence activation.