ADAM33 Silencing Inhibits Vascular Smooth Muscle Cell Migration and Regulates Cytokine Secretion in Airway Vascular Remodeling via the PI3K/AKT/mTOR Pathway.

Introduction: Vascular smooth muscle cells (VSMCs) are highly involved in airway vascular remodeling in asthma. Objectives: This study aimed to investigate the mechanisms underlying the effects of a disintegrin and metalloproteinase-33 (ADAM33) gene on the migration capacity and inflammatory cytokine secretion of VSMCs. Methods: Human aortic smooth muscle cells (HASMCs) were transfected with lentiviral vectors carrying short hairpin RNA (shRNA) targeting ADAM33 or negative control vectors. The migration capacity of HASMCs was evaluated by a transwell assay. The levels of secreted inflammatory cytokines were measured using enzyme-linked immunosorbent assay (ELISA) kits. Reverse transcription-quantitative polymerase chain reaction and Western blot assays were performed to detect mRNA and protein expression levels. Results: Silencing of ADAM33 significantly inhibited the migration of HASMCs. The expression of tumor necrosis factor alpha (TNF-α) in the supernatant of HASMCs was decreased, while that of interferon gamma (IFN-γ) was increased after the transfection of shRNA targeting ADAM33. Insufficient ADAM33 expression also suppressed the expression levels of phosphatidylinositol 3-kinase (PI3K), phospho-protein kinase B (AKT), phospho-mammalian target of rapamycin (mTOR), Rho-associated protein kinases, phospho-forkhead box protein O1 (FOXO1), and cyclin D1, but it did not affect the levels of AKT, mTOR, or Rho. Conclusion: Silencing of the ADAM33 gene inhibited HASMC migration and regulated inflammatory cytokine secretion via targeting the PI3K/AKT/mTOR pathway and its downstream signaling. These data contribute to a better understanding of the regulatory mechanisms of airway vascular remodeling in asthma.

Nuclear Receptor Nur77 Protects Against Abdominal Aortic Aneurysm by Ameliorating Inflammation Via Suppressing LOX-1.

Background Abdominal aortic aneurysm (AAA) is a life-threatening vascular disorder characterized by chronic inflammation of the aortic wall, which lacks effective pharmacotherapeutic remedies and has an extremely high mortality. Nuclear receptor NR4A1 (Nur77) functions in various chronic inflammatory diseases. However, the influence of Nur77 on AAA has remained unclear. Herein, we sought to determine the effects of Nur77 on the development of AAA. Methods and Results We observed that Nur77 expression decreased significantly in human and mice AAA lesions. Deletion of Nur77 accelerated the development of AAA in mice, as evidenced by increased AAA incidence, abdominal aortic diameters, elastin fragmentation, and collagen content. Consistent with genetic manipulation, pharmacological activation of Nur77 by celastrol showed beneficial effects against AAA. Microscopic and molecular analyses indicated that the detrimental effects of Nur77 deficiency were associated with aggravated macrophage infiltration in AAA lesions and increased pro-inflammatory cytokines secretion and matrix metalloproteinase (MMP-9) expression. Bioinformatics analyses further revealed that LOX-1 was upregulated by Nur77 deficiency and consequently increased the expression of cytokines and MMP-9. Moreover, rescue experiments verified that LOX-1 notably aggravated inflammatory response, an effect that was blunted by Nur77. Conclusions This study firstly demonstrated a crucial role of Nur77 in the formation of AAA by targeting LOX-1, which implicated Nur77 might be a potential therapeutic target for AAA.

Age-associated proinflammatory elastic fiber remodeling in large arteries.

Elastic fibers are the main components of the extracellular matrix of the large arterial wall. Elastic fiber remodeling is an intricate process of synthesis and degradation of the core elastin protein and microfibrils accompanied by the assembly and disassembly of accessory proteins. Age-related morphological, structural, and functional proinflammatory remodeling within the elastic fiber has a profound effect upon the integrity, elasticity, calcification, amyloidosis, and stiffness of the large arterial wall. An age-associated increase in arterial stiffness is a major risk factor for the pathogenesis of diseases of the large arteries such as hypertensive and atherosclerotic vasculopathy. This mini review is an update on the key molecular, cellular, functional, and structural mechanisms of elastic fiber proinflammatory remodeling in large arteries with aging. Targeting structural and functional integrity of the elastic fiber may be an effective approach to impede proinflammatory arterial remodeling with advancing age.

In Vivo Ear Sponge Lymphangiogenesis Assay.

Lymphangiogenesis, the formation of lymphatic vessels from preexisting ones, is an important process in wound-healing physiology. Deregulation of lymphangiogenesis and lymphatic vascular remodeling have been implicated in a range of inflammatory conditions, such as lymphedema, lymphadenopathy, tumor growth, and cancer metastasis. Any attempt in understanding various parameters of the lymphangiogenic process and developing desirable therapeutic targets requires recapitulating these conditions in in vivo models. One pitfall with some experimental models is the absence of immune response, an important regulatory factor for lymphangiogenesis. We overcome this issue by using immune competent mice. In this chapter, by using Angiopoietin-2 (Ang2), a protein that belongs to the Ang/Tie signaling pathway, we describe the ear sponge assay with important adaptations, highlighting a reproducible and quantitative tool for assessment of in vivo lymphangiogenesis.

Schistosomiasis Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is a disease of the lung blood vessels that results in right heart failure. PAH is thought to occur in about 5% to 10% of patients with hepatosplenic schistosomiasis, particularly due to S. mansoni. The lung blood vessel injury may result from a combination of embolization of eggs through portocaval shunts into the lungs causing localized Type 2 inflammatory response and vessel remodeling, triggering of autonomous pathology that becomes independent of the antigen, and high cardiac output as seen in portopulmonary hypertension. The condition is likely underdiagnosed as there is little systematic screening, and risk factors for developing PAH are not known. Screening is done by echocardiography, and formal diagnosis requires invasive right heart catheterization. Patients with Schistosoma-associated PAH show reduced functional capacity and can be treated with pulmonary vasodilators, which improves symptoms and may improve survival. There are animal models of this disease that might help in understanding disease pathogenesis and identify novel targets to screen and treatment. Pathogenic mechanisms include Type 2 immunity and activation and signaling in the TGF-ß pathway. There are still major uncertainties regarding Schistosoma-associated PAH development, course and treatment.

In situ Evidence of Collagen V and Interleukin-6/Interleukin-17 Activation in Vascular Remodeling of Experimental Pulmonary Hypertension.

Several studies have reported the pathophysiologic and molecular mechanisms responsible for pulmonary arterial hypertension (PAH). However, the in situ evidence of collagen V (Col V) and interleukin-17 (IL-17)/interleukin-6 (IL-6) activation in PAH has not been fully elucidated. We analyzed the effects of collagen I (Col I), Col V, IL-6, and IL-17 on vascular remodeling and hemodynamics and its possible mechanisms of action in monocrotaline (MCT)-induced PAH. Twenty male Wistar rats were randomly divided into two groups. In the PAH group, animals received MCT 60 mg/kg intraperitoneally, whereas the control group (CTRL) received saline. On day 21, the pulmonary blood pressure (PAP) and right ventricular systolic pressure (RVSP) were determined. Lung histology (smooth muscle cell proliferation [α-smooth muscle actin; α-SMA] and periadventitial fibrosis), immunofluorescence (Col I, Col V, and α-SMA), immunohistochemistry (IL-6, IL-17, and transforming growth factor-beta [TGF-ß]), and transmission electron microscopy to detect fibronexus were evaluated. The RVSP (40 ± 2 vs. 24 ± 1 mm Hg, respectively; p < 0.0001), right ventricle hypertrophy index (65 ± 9 and 25 ± 5%, respectively; p < 0.0001), vascular periadventitial Col I and Col V, smooth muscle cell α-SMA+, fibronexus, IL-6, IL-17, and TGF-ß were higher in the MCT group than in the CTRL group. In conclusion, our findings indicate in situ evidence of Col V and IL-6/IL-17 activation in vascular remodeling and suggest that increase of Col V may yield potential therapeutic targets for treating patients with PAH.

A Notch3-Marked Subpopulation of Vascular Smooth Muscle Cells Is the Cell of Origin for Occlusive Pulmonary Vascular Lesions.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a fatal disease characterized by profound vascular remodeling in which pulmonary arteries narrow because of medial thickening and occlusion by neointimal lesions, resulting in elevated pulmonary vascular resistance and right heart failure. Therapies targeting the neointima would represent a significant advance in PAH treatment; however, our understanding of the cellular events driving neointima formation, and the molecular pathways that control them, remains limited. METHODS: We comprehensively map the stepwise remodeling of pulmonary arteries in a robust, chronic inflammatory mouse model of pulmonary hypertension. This model demonstrates pathological features of the human disease, including increased right ventricular pressures, medial thickening, neointimal lesion formation, elastin breakdown, increased anastomosis within the bronchial circulation, and perivascular inflammation. Using genetic lineage tracing, clonal analysis, multiplexed in situ hybridization, immunostaining, deep confocal imaging, and staged pharmacological inhibition, we define the cell behaviors underlying each stage of vascular remodeling and identify a pathway required for neointima formation. RESULTS: Neointima arises from smooth muscle cells (SMCs) and not endothelium. Medial SMCs proliferate broadly to thicken the media, after which a small number of SMCs are selected to establish the neointima. These neointimal founder cells subsequently undergoing massive clonal expansion to form occlusive neointimal lesions. The normal pulmonary artery SMC population is heterogeneous, and we identify a Notch3-marked minority subset of SMCs as the major neointimal cell of origin. Notch signaling is specifically required for the selection of neointimal founder cells, and Notch inhibition significantly improves pulmonary artery pressure in animals with pulmonary hypertension. CONCLUSIONS: This work describes the first nongenetically driven murine model of pulmonary hypertension (PH) that generates robust and diffuse occlusive neointimal lesions across the pulmonary vascular bed and does so in a stereotyped timeframe. We uncover distinct cellular and molecular mechanisms underlying medial thickening and neointima formation and highlight novel transcriptional, behavioral, and pathogenic heterogeneity within pulmonary artery SMCs. In this model, inflammation is sufficient to generate characteristic vascular pathologies and physiological measures of human PAH. We hope that identifying the molecular cues regulating each stage of vascular remodeling will open new avenues for therapeutic advancements in the treatment of PAH.

Nonclassical Monocytes Sense Hypoxia, Regulate Pulmonary Vascular Remodeling, and Promote Pulmonary Hypertension.

An increasing body of evidence suggests that bone marrow-derived myeloid cells play a critical role in the pathophysiology of pulmonary hypertension (PH). However, the true requirement for myeloid cells in PH development has not been demonstrated, and a specific disease-promoting myeloid cell population has not been identified. Using bone marrow chimeras, lineage labeling, and proliferation studies, we determined that, in murine hypoxia-induced PH, Ly6Clo nonclassical monocytes are recruited to small pulmonary arteries and differentiate into pulmonary interstitial macrophages. Accumulation of these nonclassical monocyte-derived pulmonary interstitial macrophages around pulmonary vasculature is associated with increased muscularization of small pulmonary arteries and disease severity. To determine if the sensing of hypoxia by nonclassical monocytes contributes to the development of PH, mice lacking expression of hypoxia-inducible factor-1α in the Ly6Clo monocyte lineage were exposed to hypoxia. In these mice, vascular remodeling and PH severity were significantly reduced. Transcriptome analyses suggest that the Ly6Clo monocyte lineage regulates PH through complement, phagocytosis, Ag presentation, and chemokine/cytokine pathways. Consistent with these murine findings, relative to controls, lungs from pulmonary arterial hypertension patients displayed a significant increase in the frequency of nonclassical monocytes. Taken together, these findings show that, in response to hypoxia, nonclassical monocytes in the lung sense hypoxia, infiltrate small pulmonary arteries, and promote vascular remodeling and development of PH. Our results demonstrate that myeloid cells, specifically cells of the nonclassical monocyte lineage, play a direct role in the pathogenesis of PH.

Immunoglobulin-driven Complement Activation Regulates Proinflammatory Remodeling in Pulmonary Hypertension.

Rationale: Pulmonary hypertension (PH) is a life-threatening cardiopulmonary disorder in which inflammation and immunity have emerged as critical early pathogenic elements. Although proinflammatory processes in PH and pulmonary arterial hypertension (PAH) are the focus of extensive investigation, the initiating mechanisms remain elusive.Objectives: We tested whether activation of the complement cascade is critical in regulating proinflammatory and pro-proliferative processes in the initiation of experimental hypoxic PH and can serve as a prognostic biomarker of outcome in human PAH.Methods: We used immunostaining of lung tissues from experimental PH models and patients with PAH, analyses of genetic murine models lacking specific complement components or circulating immunoglobulins, cultured human pulmonary adventitial fibroblasts, and network medicine analysis of a biomarker risk panel from plasma of patients with PAH.Measurements and Main Results: Pulmonary perivascular-specific activation of the complement cascade was identified as a consistent critical determinant of PH and PAH in experimental animal models and humans. In experimental hypoxic PH, proinflammatory and pro-proliferative responses were dependent on complement (alternative pathway and component 5), and immunoglobulins, particularly IgG, were critical for activation of the complement cascade. We identified Csf2/GM-CSF as a primary complement-dependent inflammatory mediator. Furthermore, using network medicine analysis of a biomarker risk panel from plasma of patients with PAH, we demonstrated that complement signaling can serve as a prognostic factor for clinical outcome in PAH.Conclusions: This study establishes immunoglobulin-driven dysregulated complement activation as a critical pathobiological mechanism regulating proinflammatory and pro-proliferative processes in the initiation of experimental hypoxic PH and demonstrates complement signaling as a critical determinant of clinical outcome in PAH.

Leukotriene B4 induces proliferation of rat pulmonary arterial smooth muscle cells via modulating GSK-3ß/ß-catenin pathway.

Leukotriene B4 (LTB4) has been found to contribute to pulmonary arterial smooth muscle cells (PASMCs) proliferation and pulmonary arterial remodeling therefore the development of pulmonary arterial hypertension (PAH). Yet, the underlying molecular mechanisms remain poorly understood. The present study aims to address this issue. Our results demonstrate that LTB4 dose- and time-dependently induced proliferation of primary cultured rat PASMCs, this was accompanied with the activation of phosphatidylinositol-3-kinase/Akt (PI3K/Akt) and extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathways, and consequent inactivation of glycogen synthase kinase-3ß (GSK-3ß), up-regulation of ß-catenin and induction of cyclin D1 expression. The presence of PI3K inhibitor (LY294002) or MEK inhibitor (U0126) or prior silencing of ß-catenin with siRNA suppressed LTB4-induced cyclin D1 up-regulation and PASMCs proliferation. In addition, inactivation or lack of GSK-3ß up-regulated ß-catenin and cyclin D1 in PASMCs. Taken together, our study indicates that activation of PI3K/Akt and ERK1/2 pathways mediates LTB4-induced PASMCs proliferation by modulating GSK-3ß/ß-catenin/cyclin D1 axis and suggests that targeting this pathway might have potential value in alleviating vascular remodeling and benefit PAH.

Depletion of CD11c+ dendritic cells in apolipoprotein E-deficient mice limits angiotensin II-induced abdominal aortic aneurysm formation and growth.

OBJECTIVE: The role of chronic inflammation in abdominal aortic aneurysm (AAA) is controversial. CD11c+ antigen-presenting cells (APCs) (dendritic cells (DCs)) have been reported in human AAA samples but their role is unclear. The effect of conditional depletion of CD11c+ cells on experimental AAA was investigated in the angiotensin II (AngII)-infused apolipoprotein E-deficient (ApoE-/-) mouse model. APPROACH: CD11c-diphtheria toxin (DT or D.tox) receptor (DTR), ovalbumin (OVA) fragment aa 140-386, and enhanced green fluorescent protein (eGFP)-ApoE-/- (CD11c.DOG.ApoE-/-) mice were generated and CD11c+ cell depletion achieved with D.tox injections (8 ng/g body weight, i.p., every-other-day). AAA formation and growth were assessed by measurement of supra-renal aortic (SRA) diameter in vivo by serial ultrasound and by morphometry assessment of harvested aortas at the end of the study. RESULTS: Depletion of CD11c+ cells by administration of D.tox on alternative days was shown to reduce the maximum diameter of AAAs induced by 28 days AngII infusion compared with controls (D.tox, 1.58 ± 0.03 mm vs Vehicle control, 1.81 ± 0.06 mm, P<0.001). CD11c+ depletion commencing after AAA establishment by 14 days of AngII infusion, was also shown to lead to smaller AAAs than controls after a further 14 days (D.tox, 1.54 ± 0.04 mm vs Vehicle control, 1.80 ± 0.03 mm, P<0.001). Flow cytometry revealed significantly lower numbers of circulating CD44hi CD62Llo effector CD4 T cells, CD44hi CD62Llo effector CD8 T cells and B220+ B cells in CD11c+ cell-depleted mice versus controls. CD11c+ depletion attenuated SRA matrix degradation indicated by decreased neutrophil elastase activity (P=0.014), lower elastin degradation score (P=0.012) and higher collagen content (P=0.002). CONCLUSION: CD11c+ cell-depletion inhibited experimental AAA development and growth associated with down-regulation of circulating effector T cells and attenuated matrix degradation. The findings suggest involvement of autoreactive immune cells in AAA pathogenesis.

RELMα Licenses Macrophages for Damage-Associated Molecular Pattern Activation to Instigate Pulmonary Vascular Remodeling.

Pulmonary hypertension (PH) is a debilitating disease characterized by remodeling of the lung vasculature. In rodents, resistin-like molecule-α (RELMα, also known as HIMF or FIZZ1) can induce PH, but the signaling mechanisms are still unclear. In this study, we used human lung samples and a hypoxia-induced mouse model of PH. We found that the human homolog of RELMα, human (h) resistin, is upregulated in macrophage-like inflammatory cells from lung tissues of patients with idiopathic PH. Additionally, at PH onset in the mouse model, we observed RELMα-dependent lung accumulation of macrophages that expressed high levels of the key damage-associated molecular pattern (DAMP) molecule high-mobility group box 1 (HMGB1) and its receptor for advanced glycation end products (RAGE). In vitro, RELMα/hresistin-induced macrophage-specific HMGB1/RAGE expression and facilitated HMGB1 nucleus-to-cytoplasm translocation and extracellular secretion. Mechanistically, hresistin promoted HMGB1 posttranslational lysine acetylation by preserving the NAD+-dependent deacetylase sirtuin (Sirt) 1 in human macrophages. Notably, the hresistin-stimulated macrophages promoted apoptosis-resistant proliferation of human pulmonary artery smooth muscle cells in an HMGB1/RAGE-dependent manner. In the mouse model, RELMα also suppressed the Sirt1 signal in pulmonary macrophages in the early posthypoxic period. Notably, recruited macrophages in the lungs of these mice carried the RELMα binding partner Bruton tyrosine kinase (BTK). hResistin also mediated the migration of human macrophages by activating BTK in vitro. Collectively, these data reveal a vascular-immune cellular interaction in the early PH stage and suggest that targeting RELMα/DAMP-driven macrophages may offer a promising strategy to treat PH and other related vascular inflammatory diseases.

An Hb-mediated circulating macrophage contributing to pulmonary vascular remodeling in sickle cell disease.

Circulating macrophages recruited to the lung contribute to pulmonary vascular remodeling in various forms of pulmonary hypertension (PH). In this study we investigated a macrophage phenotype characterized by intracellular iron accumulation and expression of antioxidant (HO-1), vasoactive (ET-1), and proinflammatory (IL-6) mediators observed in the lung tissue of deceased sickle cell disease (SCD) patients with diagnosed PH. To this end, we evaluated an established rat model of group 5 PH that is simultaneously exposed to free hemoglobin (Hb) and hypobaric hypoxia (HX). Here, we tested the hypothesis that pulmonary vascular remodeling observed in human SCD with concomitant PH could be replicated and mechanistically driven in our rat model by a similar macrophage phenotype with iron accumulation and expression of a similar mixture of antioxidant (HO-1), vasoactive (ET-1), and inflammatory (IL-6) proteins. Our data suggest phenotypic similarities between pulmonary perivascular macrophages in our rat model and human SCD with PH, indicating a potentially novel maladaptive immune response to concomitant bouts of Hb and HX exposure. Moreover, by knocking out circulating macrophages with gadolinium trichloride (GdCl3), the response to combined Hb and hypobaric HX was significantly attenuated in rats, suggesting a critical role for macrophages in the exacerbation of SCD PH.

Role of complement system in pathological remodeling of the vascular wall.

Cardiovascular diseases (CVD) remain the major cause of morbidity and mortality in Europe. The clinical complications associated to arterial wall rupture involve intimal cap rupture in complicated atherosclerotic plaques and medial rupture in abdominal aortic aneurysm (AAA). The mechanisms underlying pathological vascular remodeling include lipid accumulation, cell proliferation, redox imbalance, proteolysis, leukocyte infiltration, cell death, and eventually, thrombosis. The complement system could participate in vascular remodeling by several mechanisms, from an initial protective response that aims in the clearing of cell debris to a potential deleterious role participating in leukocyte chemotaxis and cell activation and bridging innate and adaptive immunity. We have reviewed the presence and distribution of complement components, as well as the triggers of complement activation in atherosclerotic plaques and AAA, to later assess the functional consequences of complement modulation in experimental models of pathological vascular remodeling and the potential role of complement components as potential circulating biomarkers of CVD. On the whole, complement system is a key mechanism involved in vascular remodelling, which could be useful in the diagnostic/prognostic setting, as well as a potential therapeutic target, of CVD.

Lymphatic mimicry in maternal endothelial cells promotes placental spiral artery remodeling.

Molecular heterogeneity of endothelial cells underlies their highly specialized functions during changing physiological conditions within diverse vascular beds. For example, placental spiral arteries (SAs) undergo remarkable remodeling to meet the ever-growing demands of the fetus - a process which is deficient in preeclampsia. The extent to which maternal endothelial cells coordinate with immune cells and pregnancy hormones to promote SA remodeling remains largely unknown. Here we found that remodeled SAs expressed the lymphatic markers PROX1, LYVE1, and VEGFR3, mimicking lymphatic identity. Uterine natural killer (uNK) cells, which are required for SA remodeling and secrete VEGFC, were both sufficient and necessary for VEGFR3 activation in vitro and in mice lacking uNK cells, respectively. Using Flt4Chy/+ mice with kinase inactive VEGFR3 and Vegfcfl/fl Vav1-Cre mice, we demonstrated that SA remodeling required VEGFR3 signaling, and that disrupted maternal VEGFR3 signaling contributed to late-gestation fetal growth restriction. Collectively, we identified a novel instance of lymphatic mimicry by which maternal endothelial cells promote SA remodeling, furthering our understanding of the vascular heterogeneity employed for the mitigation of pregnancy complications such as fetal growth restriction and preeclampsia.

Ovarian and endometrial immunity during the ovarian cycle.

Immune tolerance is crucial for the successful pregnancy, while immune effectors and their products are required to safeguard a fetus from the infectious pathogens. The key immune effectors, such as T, B, and natural killer (NK) cells, monocytes, macrophages, and dendritic cells take part in regulating the immune responses at the maternal-fetal interface. The immune effectors become involved in intraovarian reproductive processes as well, such as ovulation, production of corpus luteum (CL) and its degeneration and determine the quality and evolution of the oocyte during the folliculogenesis. In the cycling endometrium, NK cells are rapidly infiltrated into the endometrium after ovulation and participate in angiogenesis and spiral artery remodeling process. In this study, we reviewed the characteristics and action mechanisms of immune effectors and their products in the peripheral blood, ovary, and endometrium during the ovarian cycle, since a comprehensive understanding of immune responses during the ovarian cycle and the time of implantation can help us to predict the pregnancy outcome and take effective measures for the prevention of potential obstetrical complications.

Angiogenesis in Inflammatory Arthritis.

BACKGROUND: Angiogenesis is the outgrowth of new blood vessels from existing ones and is an early occurrence in inflamed joint tissue. It is governed by a tightly controlled balance of pro- and anti-angiogenic stimuli, which promote or inhibit generation and proliferation of new endothelial cells, vascular morphogenesis, and vessel remodeling. At the beginning, capillary formation is crucial in maintaining the supply of various nutrients as well as oxygen to the inflamed tissue. Local and systemic expression of angiogenic factors may indicate a constant remodeling of synovial vasculature. Redox signaling is closely related to angiogenesis and can alter angiogenic responses of synovial cells. In this review we discuss key issues about the endothelial pathology in inflammatory arthritis followed by a review of angiogenic processes and main angiogenic mediators. We discuss the hypoxia-vascular endothelial growth factor (VEGF)-Ang/Tie2 system and its related therapeutic implications in detail with further review of various mediator protein targets and intracellular regulatory pathway targets with their current and potential future role in preclinical or clinical setting whilst ameliorating inflammation.

CD28 Signaling Controls Metabolic Fitness of Pathogenic T Cells in Medium and Large Vessel Vasculitis.

BACKGROUND: In giant cell arteritis, vessel-wall infiltrating CD4 T cells and macrophages form tissue-destructive granulomatous infiltrates, and the artery responds with a maladaptive response to injury, leading to intramural neoangiogenesis, intimal hyperplasia, and luminal occlusion. Lesion-residing T cells receive local signals, which represent potential therapeutic targets. OBJECTIVES: The authors examined how CD28 signaling affects vasculitis induction and maintenance, and which pathogenic processes rely on CD28-mediated T-cell activation. METHODS: Vasculitis was induced by transferring peripheral blood mononuclear cells from giant cell arteritis patients into immunodeficient NSG mice engrafted with human arteries. Human artery-NSG chimeras were treated with anti-CD28 domain antibody or control antibody. Treatment effects and immunosuppressive mechanisms were examined in vivo and in vitro applying tissue transcriptome analysis, immunohistochemistry, flow cytometry, and immunometabolic analysis. RESULTS: Blocking CD28-dependent signaling markedly reduced tissue-infiltrating T cells and effectively suppressed vasculitis. Mechanistic studies implicated CD28 in activating AKT signaling, T-cell proliferation and differentiation of IFN-γ and IL-21-producing effector T cells. Blocking CD28 was immunosuppressive by disrupting T-cell metabolic fitness; specifically, the ability to utilize glucose. Expression of the glucose transporter Glut1 and of glycolytic enzymes as well as mitochondrial oxygen consumption were all highly sensitive to CD28 blockade. Also, induction and maintenance of CD4+CD103+ tissue-resident memory T cells, needed to replenish the vasculitic infiltrates, depended on CD28 signaling. CD28 blockade effectively suppressed vasculitis-associated remodeling of the vessel wall. CONCLUSIONS: CD28 stimulation provides a metabolic signal required for pathogenic effector functions in medium and large vessel vasculitis. Disease-associated glycolytic activity in wall-residing T-cell populations can be therapeutically targeted by blocking CD28 signaling.

IL-1 receptor antagonist therapy mitigates placental dysfunction and perinatal injury following Zika virus infection.

Zika virus (ZIKV) infection during pregnancy causes significant adverse sequelae in the developing fetus, and results in long-term structural and neurologic defects. Most preventive and therapeutic efforts have focused on the development of vaccines, antivirals, and antibodies. The placental immunologic response to ZIKV, however, has been largely overlooked as a target for therapeutic intervention. The placental inflammatory response, specifically IL-1ß secretion and signaling, is induced by ZIKV infection and represents an environmental factor that is known to increase the risk of perinatal developmental abnormalities. We show in a mouse model that maternally administrated IL-1 receptor antagonist (IRA; Kineret, or anakinra), following ZIKV exposure, can preserve placental function (by improving trophoblast invasion and placental vasculature), increase fetal viability, and reduce neurobehavioral deficits in the offspring. We further demonstrate that while ZIKV RNA is highly detectable in placentas, it is not correlated with fetal viability. Beyond its effects in the placenta, we show that IL-1 blockade may also directly decrease fetal neuroinflammation by mitigating fetal microglial activation in a dose-dependent manner. Our studies distinguish the role of placental inflammation during ZIKV-infected pregnancies, and demonstrate that maternal IRA may attenuate fetal neuroinflammation and improve perinatal outcomes.

Key inflammatory pathways underlying vascular remodeling in pulmonary hypertension.

Independent of the underlying cause, pulmonary hypertension (PH) remains a devastating condition that is characterized by limited survival. Cumulating evidence indicates that in addition to a dysbalance of mediators regulating vascular tone and growth factors promoting vascular remodeling, failure to resolve inflammation and altered immune processes play a pivotal role in the development and progression of PH. Here, we highlight the role of key inflammatory pathways in the pathobiology of vascular remodeling and PH, and discuss potential therapeutic interventions that may halt disease progression or even reverse pulmonary vascular remodeling. Perivascular inflammation is present in all forms of PH, and inflammatory pathways involve numerous mediators and cell types including macrophages, neutrophils, T cells, dendritic cells, and mast cells. Dysfunctional bone morphogenic protein receptor 2 (BMPR2) signaling and dysregulated immunity enable the accumulation of macrophages and other inflammatory cells in obliterative vascular lesions. Regulatory T cells (Tregs) were shown to be of particular relevance in the control of inflammatory responses. Key cytokines/chemokines include interleukin-6, functioning via classic or trans-signaling, macrophage migratory inhibitory factor (MIF), but also other mediators such as neutrophil-derived myeloperoxidase. The expanding knowledge on this topic has resulted in multiple opportunities for sophisticated therapeutic interventions.