Accumulation Of Monocytes Research Articles

MRI visualization of activated monocytes accumulation in the CNS of P301S tau mice by targeted nanoparticle technology: An approach to MRI molecular imaging of neuroinflammation

AbstractBackgroundChronic neuroinflammation plays a critical role in the pathophysiology of Alzheimer’s disease (AD) and related dementias. The CNS is immune privileged with restricted peripheral leukocyte traffic under normal physiological conditions. Neuroinflammation in disease brains is often accompanied by BBB compromise and increase CNS infiltration by activated peripheral monocytes/macrophages. Part of the inflammatory response in these cells is upregulation of the integrin, very late antigen‐4 (VLA‐4) and present a valuable target for detection and treatment of neuroinflammation.MethodIn vivo MRI scans were performed on 9 to 12 months old P301S mice on a 1 Tesla small animal MR scanner using a 2D fast spin echo inversion recovery (FSE‐IR) scan protocol that approximates a fluid‐attenuated inversion recovery (FLAIR) sequence (scan parameters: TR = 6500 ms, TE = 80 ms, TI = 2000 ms, slice thickness = 2.4 mm, matrix = 192x192, FOV = 30 mm, slices = 6, NEX = 6). Mice were pre‐scanned to obtain a baseline image and then injected with Rhodamine‐labeled VLA‐4 targeted nanoparticles bearing a T1 MR relaxive payload. Four days post‐contrast injections, they were rescanned and then euthanized and brain tissue harvested for ex‐vivo immunohistochemical analysis by confocal microscopy. Test animals included transgenic mice injected with the targeted agent (n = 6). Controls included transgenic mice injected with a non‐targeted agent (n = 6) and wild‐type age‐matched litter mates injected with the targeted agent (n = 6).ResultMR images 4 days post contrast administration showed on average, higher accumulation of the contrast agent in the brains of the test mice compared to moderate to low levels of accumulation in the control mice. The in vivo MR data is validated by ex‐vivo histology results which also showed higher Rhodamine signal intensity in brain disuse sections from the test mice compared to controls. The high accumulation in the test mice is attributed to both active and active particle uptake mechanisms while only passive mechanisms are possible in the controls.ConclusionVLA‐4 targeted MRI sensitive nanoparticles label activated monocytes/macrophages in P301S mice CNS, enabling noninvasive detection of neuroinflammatory activity and highlighting a potentially novel approach to imaging neuroinflammation in AD.

Oligosaccharides from Polygonatum Cyrtonema Hua: Structural characterization and treatment of LPS-induced peritonitis in mice

Fructooligosaccharide was isolated from Polygonatum Cyrtonema Hua (PFOS) for the first time. Structure characterized using FT-IR, MALDI-TOF-MS, NMR, AFM, and TEM, indicated that PFOS was graminan-type fructan with a degree of polymerization ranging from 5 to 10. A murine model of lipopolysaccharide (LPS)-induced peritonitis was used to evaluate the in vivo anti-inflammatory and lung protective efficacy of PFOS. The result shown that pretreatment with PFOS (1.0 mg/mL) in peritonitis-induced mice could significantly inhibit the level of pro-inflammatory cytokines (TNF-α, IL-1β) in serum (P < 0.001), increase mice survival rate from 12.5 % to 54 % (P < 0.05), and alleviated lung injury through ameliorating the damage of the pulmonary cellular architecture and reducing inflammatory monocyte accumulation in lung tissue. This effect of oligosaccharides could explain the traditional usage of P. cyrtonema as a tonic medicine for respiratory problems and it could be used as a potential natural ingredient with anti-inflammatory activity.

Modeling early stage atherosclerosis in a primary human vascular microphysiological system

Novel atherosclerosis models are needed to guide clinical therapy. Here, we report an in vitro model of early atherosclerosis by fabricating and perfusing multi-layer arteriole-scale human tissue-engineered blood vessels (TEBVs) by plastic compression. TEBVs maintain mechanical strength, vasoactivity, and nitric oxide (NO) production for at least 4 weeks. Perfusion of TEBVs at a physiological shear stress with enzyme-modified low-density-lipoprotein (eLDL) with or without TNFα promotes monocyte accumulation, reduces vasoactivity, alters NO production, which leads to endothelial cell activation, monocyte accumulation, foam cell formation and expression of pro-inflammatory cytokines. Removing eLDL leads to recovery of vasoactivity, but not loss of foam cells or recovery of permeability, while pretreatment with lovastatin or the P2Y11 inhibitor NF157 reduces monocyte accumulation and blocks foam cell formation. Perfusion with blood leads to increased monocyte adhesion. This atherosclerosis model can identify the role of drugs on specific vascular functions that cannot be assessed in vivo.

Plasma calprotectin was associated with platelet activation and no-reflow phenomenon in acute coronary syndrome

BackgroundNo-reflow occurs in 3–4% of all percutaneous coronary interventions (PCIs) and has a strong negative impact on clinical outcomes of acute coronary syndrome (ACS). Therefore, the discovery of a biomarker that can early predict the occurrence of no-reflow has great clinical significance. Multiple factors including platelet activation are relevant to no-reflow. Calprotectin is found to be a biomarker of plaque instability and is identified to be a novel diagnostic and prognostic biomarker of cardiovascular diseases. The association of plasma calprotectin with platelet activation and no-reflow phenomenon in ACS is not clear.MethodsIn this prospective study performed at Yantai Yuhuangding Hospital from 2017 to 2018, a total of 176 Chinese patients with ACS who had undergone PCIs were recruited consecutively, aged from 30 to 88 years. Angiographic no-reflow was defined as thrombolysis in myocardial infarction grade less than 3. Blood samples were collected immediately at admission for the detection of plasma calprotectin and platelet–monocyte aggregates formation. Statistical analysis was performed for the variable’s comparisons between groups and the prediction value of plasma calprotectin for no-reflow.ResultsThe mean age of the 176 included ACS patients were 64(±11) years and acute ST-segment elevation myocardial infarction (STEMI) was present in 41.5% of patients. Twenty-two patients had no-reflow during the PCI procedures and the prevalence was 12.5%. Patients with higher plasma calprotectin had a higher level of platelet–monocyte aggregates (PMA) and a higher prevalence of no-reflow (p < 0.001). The multivariate regression showed that plasma calprotectin and admission hs-cTnI were independently associated with PMA, while plasma calprotectin and serum LDL-c were independent predictors of no-reflow (p < 0.001 and p = 0.017). AUC of calprotectin for predicting no-reflow were 0.898. The cut-off value of plasma calprotectin for no-reflow was 4748.77 ng/mL with a sensitivity of 0.95 and a specificity of 0.77.ConclusionPlasma calprotectin was associated with platelet activation and may act as an early predictive biomarker of no-reflow in patients with acute coronary syndrome.

The role of Wnt signalling in development of coronary artery disease and its risk factors.

The Wnt signalling pathways are composed of a highly conserved cascade of events that govern cell differentiation, apoptosis and cell orientation. Three major and distinct Wnt signalling pathways have been characterized: the canonical Wnt pathway (or Wnt/β-catenin pathway), the non-canonical planar cell polarity pathway and the non-canonical Wnt/Ca2+ pathway. Altered Wnt signalling pathway has been associated with diverse diseases such as disorders of bone density, different malignancies, cardiac malformations and heart failure. Coronary artery disease is the most common type of heart disease in the United States. Atherosclerosis is a multi-step pathological process, which starts with lipid deposition and endothelial cell dysfunction, triggering inflammatory reactions, followed by recruitment and aggregation of monocytes. Subsequently, monocytes differentiate into tissue-resident macrophages and transform into foam cells by the uptake of modified low-density lipoprotein. Meanwhile, further accumulations of lipids, infiltration and proliferation of vascular smooth muscle cells, and deposition of the extracellular matrix occur under the intima. An atheromatous plaque or hyperplasia of the intima and media is eventually formed, resulting in luminal narrowing and reduced blood flow to the myocardium, leading to chest pain, angina and even myocardial infarction. The Wnt pathway participates in all different stages of this process, from endothelial dysfunction to lipid deposit, and from initial inflammation to plaque formation. Here, we focus on the role of Wnt cascade in pathophysiological mechanisms that take part in coronary artery disease from both clinical and experimental perspectives.

Pituitary Adenylate Cyclase-Activating Polypeptide Alleviates Intestinal, Extra-Intestinal and Systemic Inflammatory Responses during Acute Campylobacter jejuni-induced Enterocolitis in Mice.

Human Campylobacter jejuni infections are emerging, and constitute a significant health burden worldwide. The ubiquitously expressed pituitary adenylate cyclase-activating polypeptide (PACAP) is well-known for its cell-protective and immunomodulatory effects. In our actual intervention study, we used an acute campylobacteriosis model and assessed the potential disease-alleviating effects of exogenous PACAP. Therefore, secondary abiotic IL-10−/− mice were perorally infected with C. jejuni and treated with synthetic PACAP38 intraperitoneally from day 2 until day 5 post-infection. Whereas PACAP did not interfere with the gastrointestinal colonization of the pathogen, mice from the PACAP group exhibited less severe clinical signs of C. jejuni-induced disease, as compared to mock controls, which were paralleled by alleviated apoptotic, but enhanced cell proliferative responses in colonic epithelia on day 6 post-infection. Furthermore, PACAP dampened the accumulation of macrophages and monocytes, but enhanced regulatory T cell responses in the colon, which were accompanied by less IFN-γ secretion in intestinal compartments in PACAP versus mock-treated mice. Remarkably, the inflammation-dampening properties of PACAP could also be observed in extra-intestinal organs, and strikingly, even the systemic circulation on day 6 post-infection. For the first time, we provide evidence that synthetic PACAP might be a promising candidate to combat acute campylobacteriosis and post-infectious sequelae.

Induction of ketosis as a potential therapeutic option to limit hyperglycemia and prevent cytokine storm in COVID-19

The severe form of coronavirus disease 19 (COVID-19) is characterized by cytokine storm syndrome (CSS) and disseminated intravascular coagulation (DIC). Diabetes, obesity, and hypertension have, as minor common denominators, chronic low-grade inflammation and high plasma myeloperoxidase levels, which could be linked to pulmonary phagocytic hyperactivation and CSS. The hyperactivation of M1 macrophages with a proinflammatory phenotype, which is linked to aerobic glycolysis, leads to the recruitment of monocytes, neutrophils, and platelets from circulating blood and plays a crucial role in thrombo-inflammation (as recently demonstrated in COVID-19) through the formation of neutrophil extracellular traps and monocyte-platelet aggregates, which could be responsible for DIC. The modulation of glucose availability for activated M1 macrophages by means of a eucaloric ketogenic diet (EKD) could represent a possible metabolic tool for reducing adenosine triphosphate production from aerobic glycolysis in the M1 macrophage phenotype during the exudative phase. This approach could reduce the overproduction of cytokines and, consequently, the accumulation of neutrophils, monocytes, and platelets from the blood. Second, an EKD could be advantageous for the metabolism of anti-inflammatory M2 macrophages because these cells predominantly express oxidative phosphorylation enzymes and are best fed by the oxidation of fatty acids in the mitochondria. An EKD could guarantee the availability of free fatty acids, which are an optimal fuel supply for these cells. Third, an EKD, which could reduce high lactate formation by macrophages due to glycolysis, could favor the production of interferon type I, which are inhibited by excessive lactate production. From a practical point of view, the hypothesis, in addition to being proven in clinical studies, must obviously take into account the contraindications of an EKD, particularly type 1 or 2 diabetes treated with drugs that can cause hypoglycemia, to avoid the risk for side effects of the diet.

Elevated Calprotectin and Abnormal Myeloid Cell Subsets Discriminate Severe from Mild COVID-19

Blood myeloid cells are known to be dysregulated in coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2. It is unknown whether the innate myeloid response differs with disease severity and whether markers of innate immunity discriminate high-risk patients. Thus, we performed high-dimensional flow cytometry and single-cell RNA sequencing of COVID-19 patient peripheral blood cells and detected disappearance of non-classical CD14LowCD16High monocytes, accumulation of HLA-DRLow classical monocytes (Human Leukocyte Antigen - DR isotype), and release of massive amounts of calprotectin (S100A8/S100A9) in severe cases. Immature CD10LowCD101−CXCR4+/− neutrophils with an immunosuppressive profile accumulated in the blood and lungs, suggesting emergency myelopoiesis. Finally, we show that calprotectin plasma level and a routine flow cytometry assay detecting decreased frequencies of non-classical monocytes could discriminate patients who develop a severe form of COVID-19, suggesting a predictive value that deserves prospective evaluation.

Recombinant Human Soluble Thrombomodulin Suppresses Monocyte Adhesion by Reducing Lipopolysaccharide-Induced Endothelial Cellular Stiffening.

Endothelial cellular stiffening has been observed not only in inflamed cultured endothelial cells but also in the endothelium of atherosclerotic regions, which is an underlying cause of monocyte adhesion and accumulation. Although recombinant soluble thrombomodulin (rsTM) has been reported to suppress the inflammatory response of endothelial cells, its role in regulating endothelial cellular stiffness remains unclear. The purpose of this study was to investigate the impact of anticoagulant rsTM on lipopolysaccharide (LPS)-induced endothelial cellular stiffening. We show that LPS increases endothelial cellular stiffness by using atomic force microscopy and that rsTM reduces LPS-induced cellular stiffening not only through the attenuation of actin fiber and focal adhesion formation but also via the improvement of gap junction functionality. Moreover, post-administration of rsTM, after LPS stimulation, attenuated LPS-induced cellular stiffening. We also found that endothelial cells regulate leukocyte adhesion in a substrate- and cellular stiffness-dependent manner. Our result show that LPS-induced cellular stiffening enhances monocytic THP-1 cell line adhesion, whereas rsTM suppresses THP-1 cell adhesion to inflamed endothelial cells by reducing cellular stiffness. Endothelial cells increase cellular stiffness in reaction to inflammation, thereby promoting monocyte adhesion. Treatment of rsTM reduced LPS-induced cellular stiffening and suppressed monocyte adhesion in a cellular stiffness-dependent manner.

Transcatheter Aortic Valve Implantation Represents an Anti-Inflammatory Therapy Via Reduction of Shear Stress-Induced, Piezo-1-Mediated Monocyte Activation.

Aortic valve stenosis is an increasingly prevalent degenerative and inflammatory disease. Transcatheter aortic valve implantation (TAVI) has revolutionized its treatment, thereby avoiding its life-threatening/disabling consequences. Whether aortic valve stenosis is accelerated by inflammation and whether it is itself a cause of inflammation are unclear. We hypothesized that the large shear forces exerted on circulating cells, particularly on the largest circulating cells, monocytes, while passing through stenotic aortic valves result in proinflammatory effects that are resolved with TAVI. TAVI provides a unique opportunity to compare the activation status of monocytes under high shear stress (before TAVI) and under low shear stress (after TAVI). The activation status of monocytes was determined with a single-chain antibody, MAN-1, which is specific for the activated β2-integrin Mac-1. Monocyte function was further characterized by the adhesion of myocytes to stimulated endothelial cells, phagocytic activity, uptake of oxidized low-density lipoprotein, and cytokine expression. In addition, we designed a microfluidic system to recapitulate the shear rate conditions before and after TAVI. We used this tool in combination with functional assays, Ca2+ imaging, siRNA gene silencing, and pharmacological agonists and antagonists to identify the key mechanoreceptor mediating the shear stress sensitivity of monocytes. Last, we stained for monocytes in explanted stenotic aortic human valves. The resolution of high shear stress through TAVI reduces Mac-1 activation, cellular adhesion, phagocytosis, oxidized low-density lipoprotein uptake, and expression of inflammatory markers in monocytes and plasma. Using microfluidics and pharmacological and genetic studies, we could recapitulate high shear stress effects on isolated human monocytes under highly controlled conditions, showing that shear stress-dependent calcium influx and monocyte adhesion are mediated by the mechanosensitive ion channel Piezo-1. We also demonstrate that the expression of this receptor is shear stress dependent and downregulated in patients receiving TAVI. Last, we show monocyte accumulation at the aortic side of leaflets of explanted aortic valves. We demonstrate that high shear stress, as present in patients with aortic valve stenosis, activates multiple monocyte functions, and we identify Piezo-1 as the mainly responsible mechanoreceptor, representing a potentially druggable target. We demonstrate an anti-inflammatory effect and therefore a novel therapeutic benefit of TAVI.

Kupffer cells mediate the recruitment of hepatic stellate cells into the localized liver damage

Currently, there is a growing interest in understanding the cellular and molecular events of immune–cell trafficking and recruitment of hepatic stellate cells (HSCs) in liver diseases. Aberrant activation of HSCs is the key event leading to chronic liver fibrosis. However, the underlying mechanisms of the recruitment of HSCs in a locally injured liver are not clearly understood. Here, we report a new experimental approach for the study of inflammatory responses as well as the recruitment of HSCs into the localized cryolesion. We observed a significant liver damage accompanied by the up-regulation of plasma ALT and AST. In addition, we also found increased levels of MCP-1, IL-6 and IL-10 cytokines. The peak cytokine levels were detected at 8 h after injury, followed by intrahepatic infiltration of neutrophils and monocytes into the injury site (from 8 h to day 3), while the kupffer cells (KCs) and HSCs were mainly detected on day 3 after injury. Interestingly, the depletion of KCs, but not neutrophils, reduced the directional recruitment and accumulation of HSCs at the injury site. Moreover, the combinatorial recruitment of KCs and HSCs resulted in the gradual restoration of fibrotic area to almost typical histological appearance on day 14 post-injury. In conclusion, our data demonstrated a localized infiltration and accumulation of neutrophils and monocytes at a “predefined loci”, and further revealed that KCs are critical for the recruitment of HSCs during injury, and thus, may play an important role in tissue repair.

Transcriptome Based Profiling of the Immune Cell Gene Signature in Rat Experimental Colitis and Human IBD Tissue Samples.

Chronic intestinal inflammation is characteristic of Inflammatory Bowel Disease (IBD) that is associated with the exaggerated infiltration of immune cells. A complex interplay of inflammatory mediators and different cell types in the colon are responsible for the maintenance of tissue homeostasis and affect pathological conditions. Gene expression alteration of colon biopsies from IBD patients and an in vivo rat model of colitis were examined by RNA-Seq and QPCR, while we used in silico methods, such as Ingenuity Pathway Analysis (IPA) application and the Immune Gene Signature (ImSig) package of R, to interpret whole transcriptome data and estimate immune cell composition of colon tissues. Transcriptome profiling of in vivo colitis model revealed the most significant activation of signaling pathways responsible for leukocyte recruitment and diapedesis. We observed significant alteration of genes related to glycosylation or sensing of danger signals and pro- and anti-inflammatory cytokines and chemokines, as well as adhesion molecules. We observed the elevated expression of genes that implies the accumulation of monocytes, macrophages, neutrophils and B cells in the inflamed colon tissue. In contrast, the rate of T-cells slightly decreased in the inflamed regions. Interestingly, natural killer and plasma cells do not show enrichment upon colon inflammation. In general, whole transcriptome analysis of the in vivo experimental model of colitis with subsequent bioinformatics analysis provided a better understanding of the dynamic changes in the colon tissue of IBD patients.

Treatment with buprenorphine prior to EcoHIV infection of mice prevents the development of neurocognitive impairment.

Approximately 15-40% of people living with HIV develop HIV-associated neurocognitive disorders, HAND, despite successful antiretroviral therapy. There are no therapies to treat these disorders. HIV enters the CNS early after infection, in part by transmigration of infected monocytes. Currently, there is a major opioid epidemic in the United States. Opioid use disorder in the context of HIV infection is important because studies show that opioids exacerbate HIV-mediated neuroinflammation that may contribute to more severe cognitive deficits. Buprenorphine is an opioid derivate commonly prescribed for opiate agonist treatment. We used the EcoHIV mouse model to study the effects of buprenorphine on cognitive impairment and to correlate these with monocyte migration into the CNS. We show that buprenorphine treatment prior to mouse EcoHIV infection prevents the development of cognitive impairment, in part, by decreased accumulation of monocytes in the brain. We propose that buprenorphine has a novel therapeutic benefit of limiting the development of neurocognitive impairment in HIV-infected opioid abusers as well as in nonabusers, in addition to decreasing the use of harmful opioids. Buprenorphine may also be used in combination with HIV prevention strategies such as pre-exposure prophylaxis because of its safety profile.

MicroRNA-155 Deficiency Exacerbates Trypanosoma cruzi Infection.

Chagas disease, caused by the intracellular protozoan parasite Trypanosoma cruzi, is a public health problem affecting 6 to 8 million people, mainly in Latin America. The role of microRNAs in the pathogenesis of Chagas disease has not been well described. Here, we investigate the role of microRNA-155 (miR-155), a proinflammatory host innate immune regulator responsible for T helper type 1 and type 17 (Th1 and Th17) development and macrophage responses during T. cruzi infection. For this, we compared the survival and parasite growth and distribution in miR-155-/- and wild-type (WT) C57BL/6 mice. The lack of miR-155 caused robust parasite infection and diminished survival of infected mice, while WT mice were resistant to infection. Immunological analysis of infected mice indicated that, in the absence of miR-155, there was decreased interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) production. In addition, we found that there was a significant reduction of CD8-positive (CD8+) T cells, natural killer (NK) cells, and NK-T cells and increased accumulation of neutrophils and inflammatory monocytes in miR-155-/- mice. Collectively, these data indicate that miR-155 is an important immune regulatory molecule critical for the control of T. cruzi infection.

1698-P: Obesity-Induced Increase in Cystatin C Alleviates Tissue Inflammation and Hepatic Insulin Resistance

Removal of one kidney (uninephrectomy; UniNx) in mice reduced high fat-diet (HFD)-induced adipose tissue inflammation thereby improving adipose tissue and hepatic insulin sensitivity. Such finding was accompanied by increased circulating cystatin C levels in UniNx compared to sham-operated mice. Importantly, cystatin C may have anti-inflammatory properties, and circulating cystatin C levels were reported to positively correlate with obesity as well as type 2 diabetes. However, the causal relationship of such correlation remains unclear. Herein, HFD feeding of cystatin C-deficient (CysC KO) mice aggravated obesity-associated adipose tissue dysfunction and inflammation, as reflected by an accumulation of pro-inflammatory monocytes and elevated expression of pro-inflammatory mediators. Moreover, markers of adipocyte differentiation were decreased. Similarly to findings in adipose tissue, expression of pro-inflammatory cytokines was increased in liver and skeletal muscle of HFD-fed CysC KO mice. In line, HFD-induced hepatic insulin resistance and impairment of glucose tolerance were further aggravated in knockout mice. Consistently, chow-fed CysC KO mice were more susceptible to lipopolysaccharide (LPS)-induced adipose tissue inflammation. In people with obesity, circulating cystatin C levels correlated negatively with mRNA expression of pro-inflammatory cytokines such as Hif1α as well as IL-6. Moreover, healthy (i.e., insulin-sensitive) subjects with obesity depicted significantly higher mRNA expression of cystatin C in subcutaneous white adipose tissue. In conclusion, cystatin C is upregulated under obesity conditions and thereby counteracts inflammation of peripheral insulin-sensitive tissues and, thus, obesity-associated deterioration of glucose metabolism. Disclosure M.A. Dedual: None. S. Wueest: None. T. Challa: None. F. Lucchini: None. T. Aeppli: None. M. Borsigova: None. A.A. Mauracher: None. S. Vavassori: None. J. Pachlopnik Schmid: Advisory Panel; Self; Novartis AG, Swedish Orphan Biovitrum. M. Blüher: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Lilly Diabetes, Novo Nordisk A/S, Sanofi. Speaker’s Bureau; Self; Amgen, Novartis AG. D. Konrad: Research Support; Self; Novo Nordisk A/S. Funding Children’s Research Centre; University Children’s Hospital Zurich; University of Zurich (FK-18-027); Swiss National Science Foundation (310030-160129, 10030-179344); Wolfermann-Nägeli Foundation

Eukaryotic elongation factor-2 kinase (eEF2K) signaling in tumor and microenvironment as a novel molecular target

Eukaryotic elongation factor-2 kinase (eEF2K), an atypical member of alpha-kinase family, is highly overexpressed in breast, pancreatic, brain, and lung cancers, and associated with poor survival in patients. eEF2K promotes cell proliferation, survival, and aggressive tumor characteristics, leading to tumor growth and progression. While initial studies indicated that eEF2K acts as a negative regulator of protein synthesis by suppressing peptide elongation phase, later studies demonstrated that it has multiple functions and promotes cell cycle, angiogenesis, migration, and invasion as well as induction of epithelial-mesenchymal transition through induction of integrin β1, SRC/FAK, PI3K/AKT, cyclin D1, VEGF, ZEB1, Snail, and MMP-2. Under stress conditions such as hypoxia and metabolic distress, eEF2K is activated by several signaling pathways and slows down protein synthesis and helping cells to save energy and survive. In vivo therapeutic targeting of eEF2K by genetic methods inhibits tumor growth in various tumor models, validating it as a potential molecular target. Recent studies suggest that eEF2K plays a role in tumor microenvironment cells by monocyte chemoattractant protein-1 (MCP-1) and accumulation of tumor-associated macrophages. Due to its clinical significance and the pivotal role in tumorigenesis and progression, eEF2K is considered as an important therapeutic target in solid tumors. However, currently, there is no specific and potent inhibitor for translation into clinical studies. Here, we aim to systematically review current knowledge regarding eEF2K in tumor biology, microenvironment, and development of eEF2K targeted inhibitors and therapeutics.

NMP4 regulates innate immune responses to influenza A virus infection

Abstract Severe influenza A virus infection typically triggers excessive and detrimental lung inflammation with massive cell infiltration and hyper-production of cytokines and chemokines. Defining research models to alleviate lung damage without compromising viral control is critical. We identified a novel function for nuclear matrix protein 4 (NMP4), a zinc-finger-containing transcription factor in regulating lung inflammation and antiviral innate immune responses. Nmp4-deficient mice are protected from H1N1 influenza infection, losing less body weight compared to the wild-type mice. Nmp4-deficiency does not affect viral clearance or adaptive immune responses, but significantly reduces the accumulation of neutrophils and monocytes in the lungs and the early inflammation. Consistent with fewer innate cells in the airways, infected Nmp4-deficient mice show decreased expression of chemokine genes Ccl2 and Cxcl1 as well as pro-inflammatory cytokine genes Il1b and Il6. We further reveal that NMP4 binds to the promoters and/or conserved non-coding sequences (CNS) of Ccl2 and Cxcl1 in mouse lung epithelial cells. Besides, the knockdown of NMP4 by CRISPR/Cas9 or siRNA significantly lessens the luciferase activities of Ccl2 and Cxcl1 promoters and/or CNS. Taken together, our data suggest that NMP4 regulates monocyte- and neutrophil-attracting chemokine expression in airway epithelial cells upon influenza infection, resulting in exaggerated innate inflammation and lung tissue damage.

EPH receptor B2 stimulates human monocyte adhesion and migration independently of its EphrinB ligands.

The molecular basis of atherosclerosis is not fully understood and mice studies have shown that Ephrins and EPH receptors play a role in the atherosclerotic process. We set out to assess the role for monocytic EPHB2 and its Ephrin ligands in human atherosclerosis and show a role for EPHB2 in monocyte functions independently of its EphrinB ligands. Immunohistochemical staining of human aortic sections at different stages of atherosclerosis showed that EPHB2 and its ligand EphrinB are expressed in atherosclerotic plaques and that expression proportionally increases with plaque severity. Functionally, stimulation with EPHB2 did not affect endothelial barrier function, nor did stimulation with EphrinB1 or EphrinB2 affect monocyte‐endothelial interactions. In contrast, reduced expression of EPHB2 in monocytes resulted in decreased monocyte adhesion to endothelial cells and a decrease in monocyte transmigration, mediated by an altered morphology and a decreased ability to phosphorylate FAK. Our results suggest that EPHB2 expression in monocytes results in monocyte accumulation by virtue of an increase of transendothelial migration, which can subsequently contribute to atherosclerotic plaque progression.

Lymph node stromal CCL2 limits antibody responses.

Nonhematopoietic stromal cells in lymph nodes such as fibroblastic reticular cells (FRCs) can support the survival of plasmablasts and plasma cells [together, antibody-forming cells (AFCs)]. However, a regulatory function for the stromal compartment in AFC accumulation has not been appreciated. Here, we show that chemokine ligand 2 (CCL2)-expressing stromal cells limit AFC survival. FRCs express high levels of CCL2 in vessel-rich areas of the T cell zone and the medulla, where AFCs are located. FRC CCL2 is up-regulated during AFC accumulation, and we use lymph node transplantation to show that CCL2 deficiency in BP3+ FRCs and lymphatic endothelial cells increases AFC survival without affecting B or germinal center cell numbers. Monocytes are key expressers of the CCL2 receptor CCR2, as monocyte depletion and transfer late in AFC responses increases and decreases AFC accumulation, respectively. Monocytes express reactive oxygen species (ROS) in an NADPH oxidase 2 (NOX2)-dependent manner, and NOX2-deficient monocytes fail to reduce AFC numbers. Stromal CCL2 modulates both monocyte accumulation and ROS production, and is regulated, in part, by manipulations that modulate vascular permeability. Together, our results reveal that the lymph node stromal compartment, by influencing monocyte accumulation and functional phenotype, has a regulatory role in AFC survival. Our results further suggest a role for inflammation-induced vascular activity in tuning the lymph node microenvironment. The understanding of stromal-mediated AFC regulation in vessel-rich environments could potentially be harnessed to control antibody-mediated autoimmunity.

In This Issue

HomeCirculation ResearchVol. 126, No. 1In This Issue Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessIn BriefPDF/EPUBIn This Issue Ruth Williams Ruth WilliamsRuth Williams Search for more papers by this author Originally published2 Jan 2020https://doi.org/10.1161/RES.0000000000000319Circulation Research. 2020;126:2is related toTriglyceride Paradox Is Related to Lipoprotein Size, Visceral Adiposity and Stearoyl-CoA Desaturase Activity in Black Versus White WomenRapamycin-Loaded Biomimetic Nanoparticles Reverse Vascular Inflammationis related toEnriched Marine Oil Supplements Increase Peripheral Blood Specialized Pro-Resolving Mediators Concentrations and Reprogram Host Immune ResponsesBiomimetic Particles Reduce Vascular Inflammation (p 25)Can Atherosclerosis be Reversed? Rapamycin-loaded nanoparticles curb vascular inflammation without toxicity, report Boada et al.Download figureDownload PowerPointIn addition to excessive lipids in the blood, inflammation is a key driver of atherosclerosis. Indeed, plaques grow as a result of fatty deposits and the accumulation and proliferation of monocytes and macrophages in the vessel walls. In mice, such proliferation can be inhibited by the systemic administration of the immunosuppressive compound rapamycin. However, because such treatment can cause toxic side effects, researchers are investigating tissue-localized delivery methods. One such approach suggested by Boada and colleagues is to use rapamycin-loaded leukosomes—nanoparticles encapsulated in a lipid coating containing leukocyte membrane proteins. The coating enables the particles to mimic leukocyte homing such that they accumulate at atherosclerotic plaques. And now the team has shown that with a rapamycin payload, the particles reduce plaque macrophage proliferation better than systemic administration of the drug. Following 7 days of once-daily rapamycin-leukosome administration, plaque burden in atherosclerosis model mice was significantly lower than in control animals. Importantly, no toxicity was detected. These proof-of-principle results now set the stage for further testing in larger, clinically relevant animals, say the authors.Upregulation of Plasma SPM by Enriched Marine Oils (p 75)Can fish oil help human immunity? SPMs indicate the clinical efficacy of fatty acid supplementation, say Souza et al.Download figureDownload PowerPointIn the body, essential fatty acids, such as those found in fish oils, are converted into specialized proresolving mediators (SPMs)—molecules that promote phagocytosis of dead cells and reduce inflammation. Whether taking such oils reduces vascular inflammation in people, however, is unclear. Some studies show the oils reduce inflammation, others show no effect. One problem is that there is no impartial measure of the clinical efficacy of such supplementation. Souza and colleagues, therefore, performed a double-blind, placebo-controlled study to determine the effects of marine oil supplementation on both SPM levels and immune cell function. Twenty-two volunteers were randomly assigned to receive placebo or 1 of 3 doses of marine oil. Blood samples from the subjects revealed a dose-dependent increase in SPMs that was significant in the 2 high-dose groups and peaked a few hours after dosing. The team went on to show that, in the high-dose blood samples, monocytes and neutrophils had increased phagocytic activity while leukocyte activation was decreased. These effects persisted after SPM levels returned to baseline. The results suggest SPMs are not only likely mediators of fatty acid-induced immune effects but that they could be useful efficacy indicators for future trials.Triglyceride Lipoproteins and Insulin Resistance (p 94)Chung et al tackle the triglyceride paradox and discover size of the lipoproteins matters.Download figureDownload PowerPointA high level of triglycerides in the blood is a marker of cardiometabolic disease—a collection of symptoms including insulin resistance, obesity, dyslipidemia, and hypertension. However, this correlation does not occur in people of African ancestry. Indeed, black individuals may have apparently low triglyceride levels even when symptoms of cardiometabolic disease are present. To get to the bottom of this paradox, Chung and colleagues examined triglycerides in blood samples from black and white women to see if a specific subfraction of the lipoproteins—based on particle size—might correlate with symptoms. Women (122) of similar ages, body mass indices, and backgrounds had blood samples collected for insulin sensitivity tests and triglyceride measurements. The team found that while levels of large, medium, and small triglycerides were lower in blacks than whites regardless of insulin sensitivity, levels of very small triglycerides, which are known to be proatherogenic, did correlate with insulin sensitivity in both racial groups. The findings could not only form the basis of more accurate triglyceride tests for assessing cardiovascular disease severity in all races, but also highlight the potential importance of very small triglycerides in contributing to the progression of the condition. Previous Back to top Next FiguresReferencesRelatedDetailsRelated articlesTriglyceride Paradox Is Related to Lipoprotein Size, Visceral Adiposity and Stearoyl-CoA Desaturase Activity in Black Versus White WomenStephanie T. Chung, et al. Circulation Research. 2020;126:94-108Rapamycin-Loaded Biomimetic Nanoparticles Reverse Vascular InflammationChristian Boada, et al. Circulation Research. 2020;126:25-37Enriched Marine Oil Supplements Increase Peripheral Blood Specialized Pro-Resolving Mediators Concentrations and Reprogram Host Immune ResponsesPatricia R. Souza, et al. Circulation Research. 2020;126:75-90 January 3, 2020Vol 126, Issue 1 Advertisement Article InformationMetrics © 2019 American Heart Association, Inc.https://doi.org/10.1161/RES.0000000000000319 Originally publishedJanuary 2, 2020 PDF download Advertisement