Background
Activated T cells and dendritic cells (DCs) are colocalized in atherosclerotic plaques in association with plaque rupture. Oxidized low‐density lipoprotein (oxLDL) promotes immune ...activation and inflammation. We studied the effects of statins (atorvastatin and simvastatin) on human DC maturation and T‐cell activation.
Methods and Results
Human peripheral blood monocytes were differentiated to DCs and stimulated with oxLDL. T cells were isolated from carotid endarterectomy specimens from patients undergoing carotid endarterectomy or from healthy individuals. Naïve T cells were cocultured with pretreated DCs. The effects of statin were studied. OxLDL induced DC maturation and T‐cell activation. OxLDL induced atherogenic heat shock proteins (HSP) 60 and 90 and decreased potentially atheroprotective heat shock protein 27, effects restored by atorvastatin. T cells exposed to oxLDL‐treated DCs produced interferon‐γ and interleukin (IL)‐17. Atorvastatin and simvastatin suppressed the DC maturation showing lower expression of CD80, CD83, and CD86, and limited their production of tumor necrosis factor‐α, IL‐1β and IL‐6, and increased transforming growth factor‐β and IL‐10 secretion. Statin‐treated DCs inhibited Th1 and/or Th17 polarization by downregulation of transcriptional factors T‐bet and RORγt expression, and induced T regulatory cells with IL‐10 production. OxLDL‐induced miRNA let7c and phosphorylation of Akt and ERK were repressed by statins. Let‐7c had a pivotal role in mediating effect of oxLDL. Experiments on T cells derived from carotid atherosclerotic plaques or healthy individuals showed similar results.
Conclusions
Statins repress human DC maturation induced by oxLDL, limit T‐cell activation, and repress an atherogenic heat shock protein profile and promote induction of T regulatory cells. MicroRNA let‐7c is integral to the effects.
Phosphorylcholine (PC) is a classic T-independent Ag that is exposed on apoptotic cells, oxidized phospholipids, and bacterial polysaccharides. Experimental as well as epidemiological studies have ...over the past decade implicated Abs against PC (anti-PC) as anti-inflammatory and a strong protective factor in cardiovascular disease. Although clinically important, little is known about the development of anti-PC in humans. This study was conceived to dissect the human anti-PC repertoire and generate human mAbs. We designed a PC-specific probe to identify, isolate, and characterize PC-reactive B cells from 10 healthy individuals. The donors had all mounted somatically mutated Abs toward PC using a broad variety of Ig genes. PC-reactive B cells were primarily found in the IgM(+) memory subset, although significant numbers also were detected among naive, IgG(+), and CD27(+)CD43(+) B cells. Abs from these subsets were clonally related, suggesting a common origin. mAbs derived from the same donors exhibited equivalent or higher affinity for PC than the well-characterized murine T-15 clone. These results provide novel insights into the cellular and molecular ontogeny of atheroprotective PC Abs, thereby offering new opportunities for Ab-based therapeutic interventions.
Background
Atherosclerosis is characterized by the presence of activated immune‐competent cells including dendritic cells (DCs) and T cells, dead cells, and oxidized low‐density lipoprotein. HSP60 ...(Heat shock protein 60) has been implicated in atherosclerosis. A plasma protein, Annexin A5, has atheroprotective properties.
Methods and Results
Human DCs differentiated from peripheral blood monocytes were treated with human HSP60 or HSP90 and autologous T cells were cocultured with these pretreated DCs (mDCs). HSP60 induced mDCs and T‐cell activation as determined by FACScan (Fluorescence associated cell scan), gene‐activation, and cytokine production. HSP60‐induced T‐cell activation was partly major histocompatibility complex class II–dependent. T cells exposed to HSP60‐treated mDCs produced interferon‐γ, interleukin‐17, but not transforming growth factor‐β. HSP60 did not promote expression of Toll‐like receptors 2 or 4. HSP90 promoted mDCs maturation but had no effect on T‐cell activation. Annexin A5 inhibited HSP60‐proinflammatory Th1/Th17 effects on mDCs and T cells, and partly bound HSP60. Further, Annexin A5 inhibited HSP‐induced activation of mDCs and also oxidized low‐density lipoprotein–induced HSP‐production from mDCs. Experiments on mDCs and T cells derived from carotid atherosclerotic plaques from patients with symptomatic carotid disease gave similar results as from blood donors.
Conclusions
HSP60 induces mDCs activation and partly major histocompatibility complex class II–dependent activation of blood‐ and plaque‐derived T cells, which is mostly of Th1/Th17 type. HSP60 could thus be an important T‐cell antigen in plaques, and also mediate oxidized low‐density lipoproteins immunogenic effects on DC‐T‐cell activation, promoting plaque rupture and clinical manifestations of cardiovascular disease. Annexin A5 inhibits both oxidized low‐density lipoprotein–induced HSP60, and HSP60‐mediated immune activation, which suggests a potential therapeutic role.
Purpose Interferon-γ inhibits cancer cell proliferation and induces re-expression of different tumor suppressor genes. As a candidate, HEPACAM is almost lost in bladder transitional cell carcinoma. ...To our knowledge whether interferon-γ inhibits BIU-87 proliferation and re-expresses HEPACAM mRNA is still unknown. Thus, we probed the mechanism and examined the correlations between interferon-γ in patient serum and HEPACAM in bladder transitional cell carcinoma. Materials and Methods Using enzyme-linked immunosorbent assay we measured serum interferon-γ in 27 men and 6 women, and 15 volunteers. Disease was Ta–T1 in 12 patients, T2–T4 in 21, low grade in 25, high grade in 8, primary in 13 and recurrent in 20. A total of 33 cancer and 26 adjacent tissues were examined by immunohistochemistry to detect HEPACAM protein and ensure the position. Under interferon-γ stimulation we detected BIU-87 proliferation by MTT assay. Cell cycles were examined by flow cytometry. HEPACAM mRNA expression was determined by reverse transcription-polymerase chain reaction. Western blot was used to detect p21WAF1. Results Interferon-γ was remarkably low in patients with bladder transitional cell carcinoma vs volunteers (p <0.01). HEPACAM protein was highly expressed in adjacent tissue, mainly at the cytomembrane, but it was almost absent in bladder transitional cell carcinoma (p <0.01). The interferon-γ decrease in the serum of patients with bladder transitional cell carcinoma and the low HEPACAM expression in tumors correlated linearly (r = 0.899, p <0.01). In vitro interferon-γ inhibited BIU-87 proliferation (p <0.01) and slightly re-expressed HEPACAM mRNA (p <0.05). The cell cycle was arrested at G0 /G1 and p21WAF1 was concurrently increased in response to interferon-γ (p <0.01). Conclusions Results suggest an important connection between HEPACAM and interferon-γ, which may inhibit BIU-87 proliferation through HEPACAM re-expression and p21WAF1 up-regulation to arrest cells at the G0 /G1 phase.
Objective
We study activation of T helper 17 (Th17) and regulatory T (Treg) cells and induction of apoptosis in cells from patients with systemic lupus erythematosus (SLE) compared with controls and ...effects of atorvastatin and its simulated interactions with other compounds.
Methods
Mononuclear cells from 10 patients with SLE and 10 controls were cultured in conditions that induce Th17 and/or Treg cell polarization and/or apoptosis and were studied by FACScan. Gene expression was determined by quantitative real‐time reverse transcription–polymerase chain reaction. Cytokines in plasma were determined by enzyme‐linked immunosorbent assay. The Search Tool for Interactions of Chemicals (STITCH) was used to retrieve information regarding the binding properties of atorvastatin.
Results
Among patients with SLE, the proportion of Th17 (CD4+IL17+) cells was higher compared with controls after activation, with Th17 or Treg polarizing cytokines, phorbol myristate acetate, and ionomycin. In contrast, Treg cells (CD4+CD25+CD127dim/−) frequencies were lower. CD95 stimulation induced relatively more apoptosis in Treg cells and less in Th17 cells, as compared with controls. Addition of atorvastatin normalized Th17/Treg cell balance and apoptosis induction. Accordingly, the ratio of RORC/FoxP3 decreased in patients with SLE. Interleukin 17 and interleukin 6 (IL‐6) levels were increased in patients with SLE. Atorvastatin interacted strongly with C‐reactive protein (CRP) and also significantly with IL‐6.
Conclusion
There is a higher proportion of Th17 cells and a lower proportion of Treg cells in patients with SLE after activation. Th17 cells were more resistant than Treg cells to CD95‐induced apoptosis in SLE. Atorvastatin normalized these effects. Our findings reveal a novel mechanism behind the imbalance of Th17/Treg cells with implications for treatment in SLE. We determine for the first time simulated interaction between atorvastatin, CRP, and IL‐6, implying a novel role of atorvastatin.
We study the platoon control of vehicles with third-order nonlinear dynamics under the constant time headway spacing policy. We consider a vehicle model with parameter uncertainties and external ...disturbances and propose a distributed control law based on an event-triggered extended state observer. First, an event-triggered extended state observer is designed to estimate the unmodeled dynamics in the vehicle model. Then based on the estimate of the unmodeled dynamics, a distributed control law is designed by using a modified dynamic surface control method. The control law of each follower vehicle only uses the information obtained by on-board sensors, including its own velocity, acceleration, the velocity difference between adjacent vehicles and the inter-vehicle distance. Finally, we give the range of the control parameters to ensure the stability of the vehicle platoon system. It is shown that the control parameters can be properly designed to make the observation errors of the extended state observers bounded and ensure the closed-loop stability. We prove that the Zeno behavior is avoided under the designed event-triggered mechanism. The joint simulations by using CarSim and MATLAB are given to demonstrate the effectiveness of the proposed control law.
Background
Malondialdehyde (MDA) is generated during lipid peroxidation as in oxidized low‐density lipoprotein, but antibodies against oxidized low‐density lipoprotein show variable results in ...clinical studies. We therefore studied the risk of cardiovascular disease (CVD) associated with IgM antibodies against MDA conjugated with human albumin (anti‐MDA).
Methods and Results
In a 5‐ to 7‐year follow‐up of 60‐year‐old men and women from Stockholm County previously screened for cardiovascular risk factors (2039 men, 2193 women), 209 incident CVD cases (defined as new events of coronary heart disease, fatal and nonfatal myocardial infarction, ischemic stroke, and hospitalization for angina pectoris) and 620 age‐ and sex‐matched controls were tested for IgM anti‐MDA by ELISA. Antibody peptide/protein characterization was done using a proteomics de novo sequencing approach. After adjustment for smoking, body‐mass index, type 2 diabetes mellitus, hyperlipidemia, and hypertension, an increased CVD risk was observed in the low IgM anti‐MDA percentiles (below 10th and 25th) (odds ratio and 95% CI: 2.0; 1.19–3.36 and 1.67; 1.16–2.41, respectively). Anti‐MDA above the 66th percentile was associated with a decreased CVD risk (odds ratio 0.68; CI: 0.48–0.98). After stratification by sex, associations were only present among men. IgM anti‐MDA levels were lower among cases (median interquartile range: 141.0 112.7–164.3 versus 147.4 123.5–169.6; P=0.0177), even more so among men (130.6 107.7–155.3 versus 143.0 120.1–165.2; P=0.001). The IgM anti‐MDA variable region profiles are distinctly different and also more homologous in their content (correlates strongly with fewer peptides) than control antibodies (not binding MDA).
Conclusions
IgM anti‐MDA is a protection marker for CVD. This finding could have diagnostic and therapeutic implications.
We study platoon control of vehicles with linear third-order longitudinal dynamics under the constant time headway policy. The controller of each follower vehicle is only based on its own velocity, ...acceleration, inter-vehicle distance and velocity difference with respect to its immediate predecessor, which are all obtained by on-board sensors. We develop distributed cooperative extended state observers for followers to estimate the acceleration differences between adjacent vehicles. Based on estimates of the acceleration differences, distributed cooperative control laws are designed. By using the stability theory of perturbed linear systems, we show that the control parameters can be properly designed to ensure the closed-loop and L2 string stabilities for any given positive time headway. We further show that the proposed control law based on the ideal vehicle model can guarantee the closed-loop and L2 string stabilities even if there are small model parameter uncertainties. Also, simulation results demonstrate the robustness of the proposed control law against sensing noises, input delays and parameter uncertainties.
Summary
Refractory anaemia with ring sideroblasts (RARS) is characterized by anaemia, erythroid apoptosis, cytochrome c release and mitochondrial ferritin accumulation. Granulocyte‐colony‐stimulating ...factor (G‐CSF) inhibits the first three of these features in vitro and in vivo. To dissect the molecular mechanisms underlying the RARS phenotype and anti‐apoptotic effects of G‐CSF, erythroblasts generated from normal (NBM) and RARS marrow CD34+ cells were cultured ±G‐CSF and subjected to gene expression analysis (GEP). Several erythropoiesis‐associated genes that were deregulated in RARS CD34+ cells showed normal expression in erythroblasts, underscoring the importance of differentiation‐specific GEP. RARS erythroblasts showed a marked deregulation of several pathways including apoptosis, DNA damage repair, mitochondrial function and the JAK/Stat pathway. ABCB7, transporting iron from mitochondria to cytosol and associated with inherited ring sideroblast formation was severely suppressed and expression decreased with differentiation, while increasing in NBM cultures. The same pattern was observed for the mitochondrial integrity gene MFN2. Other downregulated key genes included STAT5B, HSPA5, FANCC and the negative apoptosis regulator MAP3K7. Methylation status of key downregulated genes was normal. The mitochondrial pathway including MFN2 was significantly modified by G‐CSF, and several heat shock protein genes were upregulated, as evidence of anti‐apoptotic protection of erythropoiesis. By contrast, G‐CSF had no effect on iron‐transport or erythropoiesis‐associated genes.
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