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Following a cerebral ischemic event, substantial alterations in both cellular and molecular activities occur due to ischemia-induced cerebral pathology. Mounting evidence indicates that the robust recruitment of immune cells plays a central role in the acute stage of stroke. Infiltrating peripheral immune cells and resident microglia mediate neuronal cell death and blood-brain barrier disruption by releasing inflammation-associated molecules. Nevertheless, profound immunological effects in the context of the subacute and chronic recovery phase of stroke have received little attention. Early attempts to curtail the infiltration of immune cells were effective in mitigating brain injury in experimental stroke studies but failed to exert beneficial effects in clinical trials. Neural tissue damage repair processes include angiogenesis, neurogenesis, and synaptic remodeling, etc. Post-stroke inflammatory cells can adopt divergent phenotypes that influence the aforementioned biological processes in both endothelial and neural stem cells by either alleviating acute inflammatory responses or secreting a variety of growth factors, which are substantially involved in the process of angiogenesis and neurogenesis. To better understand the multiple roles of immune cells in neural tissue repair processes post stroke, we review what is known and unknown regarding the role of immune cells in angiogenesis, neurogenesis, and neuronal remodeling. A comprehensive understanding of these inflammatory mechanisms may help identify potential targets for the development of novel immunoregulatory therapeutic strategies that ameliorate complications and improve functional rehabilitation after stroke., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Ma, Yang, He, Zhang and Chang.)

Neutrophils are first-line responders of the innate immune system. Following myocardial infarction (MI), neutrophils are quickly recruited to the ischemic region, where they initiate the inflammatory response, aiming at cleaning up dead cell debris. However, excessive accumulation and/or delayed removal of neutrophils are deleterious. Neutrophils can promote myocardial injury by releasing reactive oxygen species, granular components, and pro-inflammatory mediators. More recent studies have revealed that neutrophils are able to form extracellular traps (NETs) and produce extracellular vesicles (EVs) to aggravate inflammation and cardiac injury. On the contrary, there is growing evidence showing that neutrophils also exert anti-inflammatory, pro-angiogenic, and pro-reparative effects, thus facilitating inflammation resolution and cardiac repair. In this review, we summarize the current knowledge on neutrophils' detrimental roles, highlighting the role of recently recognized NETs and EVs, followed by a discussion of their beneficial effects and molecular mechanisms in post-MI cardiac remodeling. In addition, emerging concepts about neutrophil diversity and their modulation of adaptive immunity are discussed.

The underlying mechanism of preeclampsia by which an angiogenic imbalance results in systemic vascular endothelial dysfunction remains unclear. Complement activation directly induces endothelial dysfunction and is known to be involved in preeclampsia; nevertheless, the association between complement activation and angiogenic imbalance has not been established. This study aimed to evaluate whether angiogenic imbalance affects the expression and secretion of inhibitory complement factor H (CFH) in endothelial cells, resulting in complement activation and systemic vascular endothelial dysfunction. Viability of human umbilical vein endothelial cells (HUVECs) was assessed upon CFH knockdown by targeted-siRNA, and were incubated with complement factors. HUVECs were also treated with placental growth factor (PlGF) and/or soluble fms-like tyrosine kinase 1 (sFlt1), and CFH expression and secretion were measured. These cells were evaluated by cell viability assay and cell surface complement activation was quantified by immunocytochemical assessment of C5b-9 deposition. HUVECs transfected with CFH-siRNA had significantly lower viability than that of control cells. Moreover, the expression and secretion of CFH were significantly increased upon PlGF treatment compared with PlGF + sFlt1 combo. HUVECs treated with PlGF had less C5b-9 deposition and higher viability than HUVECs treated with PlGF + sFlt1. In summary, CFH was found to be essential for endothelial cell survival by inhibiting complement activation. An angiogenic imbalance, including decreased PlGF and increased sFlt1, suppresses CFH expression and secretion, resulting in complement activation on the surface of endothelial cells and systemic vascular endothelial dysfunction., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Several angiogenesis-dependent diseases, including age-related macular degeneration and infantile hemangioma, display differential prevalence among Black, as compared to White individuals. Although socioeconomic status and genetic architecture have been suggested as explaining these differences, we have recently shown that pigment production per se might be involved. For example, we have shown that the extracellular protein fibromodulin is a pro-angiogenic factor highly secreted by melanocytes in White but not Black individuals. Still, additional pigment-dependent angiogenic factors and their molecular mechanisms remain to be identified. Understanding the contribution of pigmentation to angiogenesis in health and disease is essential for precision medicine of angiogenesis-dependent diseases with racial disparity. Toward that goal, we compared the transcriptomes of Black and White individuals in three tissues with angiogenic activity, namely artery, whole blood, and skin. We identified several differentially expressed angiogenesis pathways, including artery morphogenesis, regulation of endothelial cell chemotaxis, and cellular response to vascular endothelial growth factor stimulus. We then demonstrated that the expression of key genes in these pathways is directly modulated by the degree of pigmentation. We further identified the precise pigment production pathway controlling the expression of these genes, namely melanocortin 1 receptor (MC1R) signaling. These results demonstrate pigment-mediated regulation of angiogenesis-related pathways and their driver genes across human tissues., Competing Interests: The authors have declared that no competing interests exist.

The novel coronavirus severe acute respiratory syndrome-CoV-2 (SARS-CoV-2) is responsible for COVID-19 infection. The COVID-19 pandemic represents one of the worst global threats in the 21st century since World War II. This pandemic has led to a worldwide economic recession and crisis due to lockdown. Biomedical researchers, pharmaceutical companies, and premier institutes throughout the world are claiming that new clinical trials are in progress. During the severe phase of this disease, mechanical ventilators are used to assist in the management of outcomes; however, their use can lead to the development of pneumonia. In this context, mesenchymal stem cell (MSC)-derived exosomes can serve as an immunomodulation treatment for COVID-19 patients. Exosomes possess anti-inflammatory, pro-angiogenic, and immunomodulatory properties that can be explored in an effort to improve the outcomes of SARS-CoV-2-infected patients. Currently, only one ongoing clinical trial (NCT04276987) is specifically exploring the use of MSC-derived exosomes as a therapy to treat SARS-CoV-2-associated pneumonia. The purpose of this review is to provide insights of using exosomes derived from mesenchymal stem cells in management of the co-morbidities associated with SARS-CoV-2-infected persons in direction of improving their health outcome. There is limited knowledge of using exosomes in SARS-CoV-2; the clinicians and researchers should exploit exosomes as therapeutic regime.

The transplantation of various immune cell types are promising approaches for the treatment of ischemic cardiovascular disease including myocardial infarction (MI) and peripheral arterial disease (PAD). Major limitation of these so-called Advanced Therapy Medicinal Products (ATMPs) is the ischemic microenvironment affecting cell homeostasis and limiting the demanded effect of the transplanted cell products. Accordingly, different clinical and experimental strategies have been evolved to overcome these obstacles. Here, we give a short review of the different experimental and clinical strategies to solve these issues due to ischemic cardiovascular disease.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation of the synovial joints. Inflammation, new blood vessel formation (angiogenesis) and bone resorption (osteoclastogenesis) are three key processes involved in the joint damage and deformities of arthritis. Various gut microbiota-derived metabolites are implicated in RA pathogenesis. However, there is barely any information about the impact of two such metabolites, indole-3-aldehyde (IAld) and indole-3-acetic acid (I3AA), on arthritis-related processes. We conducted a comparative analysis of IAld and I3AA using established cell-based models to understand how they might influence RA pathogenesis. Although structurally similar, the bioactivities of these two metabolites were profoundly different. IAld but not I3AA, inhibited the expression of pro-inflammatory cytokines (IL-1β and IL-6) in RAW 264.7 (RAW) cells stimulated with heat-killed M. tuberculosis sonicate (Mtb) and lipopolysaccharide (LPS). IAld also exhibited pro-angiogenic activity and pro-osteoclastogenic activity. In contrast, I3AA exhibited anti-angiogenic activity on endothelial cell tube formation but had no effect on osteoclastogenesis. Both IAld and I3AA have been proposed as aryl hydrocarbon receptor (AhR) agonists. Use of CH-223191, an inhibitor of the AhR, suppressed the anti-angiogenic activity of I3AA but failed to mitigate the effects of IAld. Further investigation of the anti-inflammatory activities of IAld and I3AA in LPS-treated RAW cells indicated that inhibition of MyD88-dependent activation of NF-κB and MAPK pathways was not likely involved. Our results suggest that the relative bioavailability of these indole derivatives may differentially impact RA progression and possibly other diseases that share similar cellular processes.

Regulatory T cells (Tregs) are crucial mediators of immune homeostasis. They regulate immune response by suppressing inflammation and promoting self-tolerance. In addition to their immunoregulatory role, a growing body of evidence highlights the dynamic role of Tregs in angiogenesis, the process of forming new blood vessels. Although angiogenesis is critically important for normal tissue regeneration, it is also a hallmark of pathological processes, including malignancy and chronic inflammation. Interestingly, the role of Tregs in angiogenesis has been shown to be highly tissue- and context-specific and as a result can yield either pro- or antiangiogenic effects. For these reasons, there is considerable interest in determining the molecular underpinnings of Treg-mediated modulation of angiogenesis in different disease states. The present review summarizes the role of Tregs in angiogenesis and mechanisms by which Tregs regulate angiogenesis and discusses how these mechanisms differ in homeostatic and pathological settings., (Copyright © 2020 by The American Association of Immunologists, Inc.)

Multiple sclerosis (MS) is an autoimmune disease, characterized by multiple demyelination of axons in both white and gray matter in the Central Nervous System (CNS). There is increasing evidence to support the notion that angiogenesis and chronic inflammation are mutually related. Different immune cells, including monocytes-macrophages, lymphocytes, neutrophils, mast cells (MCs) and dendritic cells are able to secrete an array of angiogenic cytokines, which promote growth, migration, and activation of endothelial cells. MCs play various roles in MS pathogenesis, influencing the innate immune response in peripheral tissues and in CNS. The aim of this review article is to discuss the role of MCs in MS pathogenesis with particular reference to the involvement of these inflammatory cells in the angiogenic processes occurring during MS.

The immunomodulatory capability of biomaterials is of paramount importance for successful material-mediated bone regeneration. Particularly, the design of surface nano-topography can be leveraged to instruct immune reactions, yet the understanding of such "nano-morphology effect" is still very limited. Herein, highly ordered nano-concave pit (denoted as NCPit) and nano-convex dot (denoted as NCDot) microarrays with two different sizes were successfully constructed on a 316LSS surface via anodization and subsequently immersion-coating treatment, respectively. We, for the first time, comparatively investigated the interactions of NCPit and NCDot microarrays with RAW264.7 macrophages and their immunomodulatory impacts on osteogenesis and angiogenesis of human bone mesenchymal stem cells (hBMSCs) and human umbilical vein endothelial cells (HUVECs). NCDot microarrays induced macrophages towards M2 polarization with the higher expression level of anti-inflammatory markers (IL-10 and CD 206) and the lower level of pro-inflammatory markers (TNF-α, IL-1β, IL-6 and CD 86) than those of the corresponding NCPit microarrays. During the process, the expressions of osteogenesis-related genes (Runx2, OPN and OCN) of hBMSCs, and angiogenesis-related genes (eNOS, HIF-1α, KDR and VEGF) of HUVECs were significantly upregulated by the NCDot microarray-modulating immune microenvironment of macrophages, and finally stimulated osteogenesis and angiogenesis. Thus, the prepared NCDot arrays were able to significantly promote osteo-/angiogenic activity by generating a more suitable immune microenvironment than NCPit arrays, offering substantial evidence for designing immunomodulatory biomaterials with specific microstructures and optimal bioactivity.

To maintain homeostasis, macrophages must be capable of assuming either an inflammatory or an anti-inflammatory phenotype. To better understand the latter, we stimulated human macrophages in vitro with TLR ligands in the presence of high-density immune complexes (IC). This combination of stimuli resulted in a broad suppression of inflammatory mediators and an upregulation of molecules involved in tissue remodeling and angiogenesis. Transcriptomic analysis of TLR stimulation in the presence of IC predicted the downstream activation of AKT and the inhibition of GSK3. Consequently, we pretreated LPS-stimulated human macrophages with small molecule inhibitors of GSK3 to partially phenocopy the regulatory effects of stimulation in the presence of IC. The upregulation of DC-STAMP and matrix metalloproteases was observed on these cells and may represent potential biomarkers for this regulatory activation state. To demonstrate the presence of these anti-inflammatory, growth-promoting macrophages in a human infectious disease, biopsies from patients with leprosy (Hanseniasis) were analyzed. The lepromatous form of this disease is characterized by hypergammaglobulinemia and defective cell-mediated immunity. Lesions in lepromatous leprosy contained macrophages with a regulatory phenotype expressing higher levels of DC-STAMP and lower levels of IL-12, relative to macrophages in tuberculoid leprosy lesions. Therefore, we propose that increased signaling by FcγR cross-linking on TLR-stimulated macrophages can paradoxically promote the resolution of inflammation and initiate processes critical to tissue growth and repair. It can also contribute to infectious disease progression., (Copyright © 2020 by The American Association of Immunologists, Inc.)

Ischemic injury initiates a sterile inflammatory response that ultimately participates in the repair and recovery of tissue perfusion. Macrophages are required for perfusion recovery during ischemia, in part because they produce growth factors that aid in vascular remodeling. The input signals governing this pro-revascularization phenotype remain of interest. Here we found that hindlimb ischemia increases levels of resolvin D1 (RvD1), an inflammation-resolving lipid mediator that targets macrophages via its receptor, ALX/FPR2. Exogenous RvD1 enhances perfusion recovery during ischemia, and mice deficient in Alx/Fpr2 have an endogenous defect in this process. Mechanistically, RNA sequencing revealed that RvD1 induces a transcriptional program in macrophages characteristic of a pro-revascularization phenotype. Vascularization of ischemic skeletal muscle, as well as cutaneous wounds, is impaired in mice with myeloid-specific deficiency of Alx/Fpr2 , and this is associated with altered expression of pro-revascularization genes in skeletal muscle and macrophages isolated from skeletal muscle. Collectively, these results uncover a role of ALX/FPR2 in revascularization that may be amenable to therapeutic targeting in diseases associated with altered tissue perfusion and repair., Competing Interests: The authors declare no competing interest.

Background: Emerging evidence has linked autophagy to skin wound healing; however, the underlying cellular and molecular mechanisms remain poorly understood. The present study was designed to determine the role of autophagy in endothelial cell (EC)-mediated skin wound healing in mice., Methods: Autophagy-related gene (Atg7) in mouse ECs was inactivated by the Cre-loxP system under the control of an EC-specific VE-Cadherin (Cdh5) promoter (Atg7 EC-/- mice). Full-thickness skin wounds were created on the dorsum of wild-type (WT), Cdh5-Cre + , floxed Atg7 (Atg7 F/F ), and Atg7 EC-/- mice. Autophagic activity was determined by autophagic flux assay in the primary culture of ECs isolated from these mice. The wound re-epithelialization and angiogenesis was examined by histological analyses. The angiogenic activity of ECs was evaluated by tube formation assay in vitro. EC proliferation was examined by a cell count CCK-8 kit. EC-originated intercellular communication with dermal fibroblasts and keratinocytes was assessed by measuring the effect of EC conditional medium on the growth of keratinocytes and fibroblasts. The levels of VEGF, EGF, bFGF in EC conditional medium were measured by ELISA., Results: Autophagy deficiency in ECs markedly enhanced the re-epithelialization and the wound closure during skin wound healing. However, it has minimal impact on angiogenesis in the wounded skin. Notably, autophagy deficiency in ECs did not affect their proliferation and migration or angiogenic activity per se but enhanced the EC conditional medium-induced proliferation and migration of keratinocytes and fibroblasts., Conclusions: These results demonstrate for the first time an inhibitory role of autophagy in the EC-originated paracrine regulation of skin wound healing., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Recent studies show that biomaterials are capable of regulating immune responses to induce a favorable osteogenic microenvironment and promote osteogenesis and angiogenesis. In this study, we investigated the effects of zinc silicate/nanohydroxyapatite/collagen (ZS/HA/Col) scaffolds on bone regeneration and angiogenesis and explored the related mechanism. We demonstrate that 10ZS/HA/Col scaffolds significantly enhanced bone regeneration and angiogenesis in vivo compared with HA/Col scaffolds. ZS/HA/Col scaffolds increased tartrate-resistant acid phosphatase (TRAP)-positive cells, nestin-positive bone marrow stromal cells (BMSCs) and CD31-positive neovessels, and expression of osteogenesis ( Bmp- 2 and Osterix ) and angiogenesis-related ( Vegf-α and Cd31 ) genes increased in nascent bone. ZS/HA/Col scaffolds with 10 wt % ZS activated the p38 signaling pathway in monocytes. The monocytes subsequently differentiated into TRAP + cells and expressed higher levels of the cytokines SDF-1, TGF-β1, VEGF-α, and PDGF-BB, which recruited BMSCs and endothelial cells (ECs) to the defect areas. Blocking the p38 pathway in monocytes reduced TRAP + differentiation and cytokine secretion and resulted in a decrease in BMSC and EC homing and angiogenesis. Overall, these findings demonstrate that 10ZS/HA/Col scaffolds modulate monocytes and, thereby, create a favorable osteogenic microenvironment that promotes BMSC migration and differentiation and vessel formation by activating the p38 signaling pathway.

Acetaminophen (APAP) overdose has become the most common cause of drug-induced acute liver failure. Angiogenesis and redox homeostasis play an important role in liver protection and repair of APAP-induced acute liver injury (AILI). Hypoxia inducible factor-1 (HIF-1) is a transcription factor that plays a crucial role in regulating the expression of genes associated with angiogenesis, redox homeostasis and energy balance. Prolyl hydroxylase 2 (PHD2) predominantly hydroxylates proline residues in HIF-1α to promote its degradation. In our previous study, we reported an intrabody against PHD2 (ER-INP) that enhances angiogenesis by blocking PHD2 activity to increase HIF-1α abundance and activity. The present study was designed to explore the role and possible mechanisms of ER-INP in AILI in mice. Mice were pretreated intravenously with ER-INP before intraperitoneal injection of APAP to induce AILI. The results showed that pretreatment with ER-INP dramatically decreased the high ALT and AST activities and significantly ameliorated the centrilobular necrosis induced by APAP administration. ER-INP expression promoted angiogenesis in vivo by upregulating the mRNA and protein levels of HIF-1α target genes. Meanwhile, ER-INP pretreatment restored redox homeostasis, verified by reinforcement of PRDX4 activity and suppression of GSH depletion. This study demonstrated that ER-INP protects against AILI in part by increasing angiogenesis and maintaining redox homeostasis. These results indicate that ER-INP may provide a potential liver protection strategy against AILI in the future., Competing Interests: Declaration of Competing Interest The authors declare that there are no conflicts of interest., (Copyright © 2019 The Author(s). Published by Elsevier Masson SAS.. All rights reserved.)

: Introduction: Antibody treatment with anti-thymocyte globulin (ATG) has been shown to be cardioprotective. We aimed to evaluate which single anti-T-cell epitope antibody alters chemokine expression at a level similar to ATG and identified CD3, which is a T-cell co-receptor mediating T-cell activation. Based on these results, the effects of anti-CD3 antibody treatment on angiogenesis and cardioprotection were tested in vitro and in vivo., Methods: Concentrations of IL-8 and MCP-1 in supernatants of human peripheral blood mononuclear cell (PBMC) cultures following distinct antibody treatments were evaluated by Enzyme-linked Immunosorbent Assay (ELISA). In vivo, anti-CD3 antibodies or vehicle were injected intravenously in rats subjected to acute myocardial infarction (AMI). Chemotaxis and angiogenesis were evaluated using tube and migration assays. Intracellular pathways were assessed using Western blot. Extracellular vesicles (EVs) were quantitatively evaluated using fluorescence-activated cell scanning, exoELISA, and nanoparticle tracking analysis. Also, microRNA profiles were determined by next-generation sequencing., Results: Only PBMC stimulation with anti-CD3 antibody led to IL-8 and MCP-1 changes in secretion, similar to ATG. In a rat model of AMI, systemic treatment with an anti-CD3 antibody markedly reduced infarct scar size (27.8% (Inter-quartile range; IQR 16.2-34.9) vs. 12.6% (IQR 8.3-27.2); p < 0.01). The secretomes of anti-CD3 treated PBMC neither induced cardioprotective pathways in cardiomyocytes nor pro-angiogenic mechanisms in human umbilical vein endothelial cell (HUVECs) in vitro. While EVs quantities remained unchanged, PBMC incubation with an anti-CD3 antibody led to alterations in EVs miRNA expression., Conclusion: Treatment with an anti-CD3 antibody led to decreased scar size in a rat model of AMI. Whereas cardioprotective and pro-angiogenetic pathways were unaltered by anti-CD3 treatment, qualitative changes in the EVs miRNA expression could be observed, which might be causal for the observed cardioprotective phenotype. We provide evidence that EVs are a potential cardioprotective treatment target. Our findings will also provide the basis for a more detailed analysis of putatively relevant miRNA candidates., Competing Interests: The authors declare no conflict of interest

Mononuclear phagocytes, such as macrophages and microglia, are key regulators of organ homeostasis including vascularization processes. Here, we investigated the role of the suppressor of cytokine signaling 3 (SOCS3) in myeloid cells as a regulator of mononuclear phagocyte function and their interaction with endothelial cells in the context of sprouting angiogenesis. As compared to SOCS3-sufficient counterparts, SOCS3-deficient microglia and macrophages displayed an increased phagocytic activity toward primary apoptotic endothelial cells, which was associated with an enhanced expression of the opsonin growth arrest-specific 6 (Gas6), a major prophagocytic molecule. Furthermore, we found that myeloid SOCS3 deficiency significantly reduced angiogenesis in an ex vivo mouse aortic ring assay, which could be reversed by the inhibition of the Gas6 receptor Mer. Together, SOCS3 in myeloid cells regulates the Gas6/Mer-dependent phagocytosis of endothelial cells, and thereby angiogenesis-related processes. Our findings provide novel insights into the complex crosstalk between mononuclear phagocytes and endothelial cells, and may therefore provide a new platform for the development of new antiangiogenic therapies., (© 2019 The Author(s) Published by S. Karger AG, Basel.)

Barriers between circulation and the central nervous system (CNS) play a key role in the development and modulation of CNS immune responses. Structural variations in the vasculature traversing different anatomical regions within the CNS strongly influence where and how CNS immune responses first develop. Here, we provide an overview of cerebrovascular anatomy, focusing on the blood-CNS interface and how anatomical variations influence steady-state immunology in the compartment. We then discuss how CNS vasculature is affected by and influences the development of different pathophysiological states, such as CNS autoimmune disease, cerebrovascular injury, cerebral ischemia, and infection., (Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Stroke is a major cause of serious disability due to the brain's limited capacity to regenerate damaged tissue and neuronal circuits. After ischemic injury, a multiphasic degenerative and inflammatory response is coupled with severely restricted vascular and neuronal repair, resulting in permanent functional deficits. Although clinical evidence indicates that revascularization of the ischemic brain regions is crucial for functional recovery, no therapeutics that promote angiogenesis after cerebral stroke are currently available. Besides vascular growth factors, guidance molecules have been identified to regulate aspects of angiogenesis in the central nervous system (CNS) and may provide targets for therapeutic angiogenesis. In this study, we demonstrate that genetic deletion of the neurite outgrowth inhibitor Nogo-A or one of its corresponding receptors, S1PR2, improves vascular sprouting and repair and reduces neurological deficits after cerebral ischemia in mice. These findings were reproduced in a therapeutic approach using intrathecal anti-Nogo-A antibodies; such a therapy is currently in clinical testing for spinal cord injury. These results provide a basis for a therapeutic blockage of inhibitory guidance molecules to improve vascular and neural repair after ischemic CNS injuries., Competing Interests: Conflict of interest statement: M.E.S. is a founder and board member of the University of Zurich spin-off company NovaGo Therapeutics Inc., seeking to develop antibody-based therapies for neurological diseases.

CXCL14 serves as a chemoattractant for activated macrophages, immature dendritic cells and natural killer cells, as well as an antiangiogenic factor by preventing the migration of endothelial cells. CXCL14 also exerts an inhibitory effect on the CXCL12/CXCR4 signaling pathway, which is involved in the maintenance of T-helper (Th)2 bias, and promotes Th1 immune response under the physiological and pathological conditions. Because CXCL14-mediated biological processes seem to be involved in the development of systemic sclerosis (SSc), which is characterized by Th2/Th17-skewed immune polarization and impaired neovascularization, we investigated the clinical correlation of serum CXCL14 levels in patients with this disease. Serum CXCL14 levels were significantly decreased in SSc patients compared with healthy individuals and in diffuse cutaneous SSc patients relative to limited cutaneous SSc patients. SSc patients with digital ulcers had serum CXCL14 levels significantly lower than those without. Furthermore, i.v. cyclophosphamide pulse significantly increased serum CXCL14 levels as compared with the baseline in SSc patients with interstitial lung disease successfully treated with this therapy. These results indicate that decreased CXCL14 expression may contribute to the maintenance of Th2-skewed immune polarization and dysregulated neovascularization, both of which underlie the developmental process of SSc., (© 2019 Japanese Dermatological Association.)

Mast cells are classically recognized as cells that cause IgE-mediated allergic reactions. However, their ability to store and secrete vascular endothelial growth factor (VEGF) suggests a role in vascular development and tumorigenesis. The current study sought to determine if other angiogenesis-related factors, in addition to VEGF, were also secreted by human tissue-derived mast cells. Using proteome array analysis and ELISA, we found that human skin-derived mast cells spontaneously secrete CXCL16, DPPIV, Endothelin-1, GM-CSF, IL-8, MCP-1, Pentraxin 3, Serpin E1, Serpin F1, TIMP-1, Thrombospondin-1, and uPA. We identified three groups based on their dependency for stem cell factor (SCF), which is required for mast cell survival: Endothelin-1, GM-CSF, IL-8, MCP-1, and VEGF (dependent); Pentraxin 3, Serpin E1, Serpin F1, TIMP-1, and Thrombospondin-1 (partly dependent); and CXCL16, DPPIV, and uPA (independent). Crosslinking of FcεRI with multivalent antigen enhanced the secretion of GM-CSF, Serpin E1, IL-8, and VEGF, and induced Amphiregulin and MMP-8 expression. Interestingly, FcεRI signals inhibited the spontaneous secretion of CXCL16, Endothelin-1, Serpin F1, Thrombospondin-1, MCP-1 and Pentraxin-3. Furthermore, IL-6, which we previously showed could induce VEGF, significantly enhanced MCP-1 secretion. Overall, this study identified several angiogenesis-related proteins that, in addition to VEGF, are spontaneously secreted at high concentrations from human skin-derived mast cells. These findings provide further evidence supporting an intrinsic role for mast cells in blood vessel formation.

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., (Copyright © 2019 Elsevier B.V. All rights reserved.)

As a component of the innate immune system, macrophages play a crucial role in host defense against a variety of microbes. Conventionally, macrophages have been classified as M1 and M2 depending on their phenotype and role in immune regulation. M1 macrophages are generally pro-inflammatory, while M2 (also known as alternatively activated macrophages) are anti-inflammatory. M1 macrophages release pro-inflammatory cytokines, reactive nitrogen, and oxygen intermediates, and kill pathogens, whereas their M2 counterparts participate in the resolution of inflammation, remodeling of tissue, angiogenesis, and tissue repair. Macrophages are also crucial in the pathogenesis of immune-inflammatory disorders, such as, arthritis. In this review, we discuss the markers of human M2 macrophages, the role played by them in inflammation or progression of rheumatic diseases, their potential to act as biomarkers, and, finally, therapeutic strategies aiming at altering/enhancing the macrophage phenotype.

Lung development is a complex process mediated through the interaction of multiple cell types, factors and mediators. In mice, it starts as early as embryonic day 9 and continues into early adulthood. The process can be separated into five different developmental stages: embryonic, pseudoglandular, canalicular, saccular, and alveolar. Whilst lung bud formation and branching morphogenesis have been studied extensively, the mechanisms of alveolarisation are incompletely understood. Aberrant lung development can lead to deleterious consequences for respiratory health such as bronchopulmonary dysplasia (BPD), a disease primarily affecting preterm neonates, which is characterised by increased pulmonary inflammation and disturbed alveolarisation. While the deleterious effects of type 1-mediated inflammatory responses on lung development have been well established, the role of type 2 responses in postnatal lung development remains poorly understood. Recent studies indicate that type 2-associated immune cells, such as group 2 innate lymphoid cells and alveolar macrophages, are increased in number during postnatal alveolarisation. Here, we present the current state of understanding of the postnatal stages of lung development and the key cell types and mediators known to be involved. We also provide an overview of how stem cells are involved in lung development and regeneration, and the negative influences of respiratory infections. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd., (Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)

Semaphorin 3A (sema3A) belongs to the sub-family of the immune semaphorins that function as regulators of immune-mediated inflammation. Sema3A is a membrane associated molecule on T regulatory cells and on B regulatory cells. Being transiently ligated to the cell surface of these cells it is suggested to be a useful marker for evaluating their functional status. In earlier studies, we found that reduced sema3A concentration in the serum of asthma patients as well as reduced expression by Treg cells correlates with asthma disease severity. Stimulation of Treg cells with recombinant sema3A induced a significant increase in FoxP3 and IL-10 expression. To find out if sema3A can be of benefit to asthma patients, we evaluated the effect of sema3A injection in a mouse model of asthma. BALB\c-mice were sensitized using ovalbumin (OVA) + adjuvant for 15 days followed by OVA aerosol inhalation over five consecutive days. Four hours following air ways sensitization on each of the above days- 15 of these mice were injected intraperitoneally with 50 μg per mouse of recombinant human sema3A-FR and the remaining 15 mice were injected with a similarly purified vehicle. Five days later the mice were sacrificed, broncheo-alveolar lavage (BAL) was collected and formalin-fixed lung biopsies taken and analyzed. In sema3A treated mice, only 20% of the bronchioles and arterioles were infiltrated by inflammatory cells as compared to 90% in the control group ( p = 0.0079). In addition, eosinophil infiltration was also significantly increased in the control group as compared with the sema3A treated mice. In sema3A treated mice we noticed only a small number of mononuclear and neutrophil cells in the BAL while in the control mice, the BAL was enriched with mononuclear and neutrophil cells. Finally, in the control mice, angiogenesis was significantly increased in comparison with sema3A treated mice as evidenced by the reduced concentration of microvessels in the lungs of sema3A treated mice. To conclude, we find that in this asthma model, sema3A functions as a potent suppressor of asthma related inflammation that has the potential to be further developed as a new therapeutic for the treatment of asthma.

Background: Optimal cell type as cell-based therapies for heart failure (HF) remains unclear. We sought to compare the safety and efficacy of direct intramyocardial transplantation of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) and human induced pluripotent stem cell-derived mesenchymal stem cells (hiPSC-MSCs) in a porcine model of HF., Methods: Eight weeks after induction of HF with myocardial infarction (MI) and rapid pacing, animals with impaired left ventricular ejection fraction (LVEF) were randomly assigned to receive direct intramyocardial injection of saline (MI group), 2 × 10 8 hESC-CMs (hESC-CM group), or 2 × 10 8 hiPSC-MSCs (hiPSC-MSC group). The hearts were harvested for immunohistochemical evaluation after serial echocardiography and hemodynamic evaluation and ventricular tachyarrhythmia (VT) induction by in vivo programmed electrical stimulation., Results: At 8 weeks post-transplantation, LVEF, left ventricular maximal positive pressure derivative, and end systolic pressure-volume relationship were significantly higher in the hiPSC-MSC group but not in the hESC-CM group compared with the MI group. The incidence of early spontaneous ventricular tachyarrhythmia (VT) episodes was higher in the hESC-CM group but the incidence of inducible VT was similar among the different groups. Histological examination showed no tumor formation but hiPSC-MSCs exhibited a stronger survival capacity by activating regulatory T cells and reducing the inflammatory cells. In vitro study showed that hiPSC-MSCs were insensitive to pro-inflammatory interferon-gamma-induced human leukocyte antigen class II expression compared with hESC-CMs. Moreover, hiPSC-MSCs also significantly enhanced angiogenesis compared with other groups via increasing expression of distinct angiogenic factors., Conclusions: Our results demonstrate that transplantation of hiPSC-MSCs is safe and does not increase proarrhythmia or tumor formation and superior to hESC-CMs for the improvement of cardiac function in HF. This is due to their immunomodulation that improves in vivo survival and enhanced angiogenesis via paracrine effects.

Type 2 immunity participates in the pathogeneses of helminth infection and allergic diseases. Emerging evidence indicates that the components of type 2 immunity are also involved in maintaining metabolic hemostasis and facilitating the healing process after tissue injury. Numerous preclinical studies have suggested regulation of type 2 immunity-related cytokines, such as interleukin-4, -13, and -33, and cell types, such as M2 macrophages, mast cells, and eosinophils, affects cardiac functions after myocardial infarction (MI), providing new insights into the importance of immune modulation in the infarcted heart. This review provides an overview of the functions of these cytokines and cells in the setting of MI as well as their potential to predict the severity and prognosis of MI.

Myocardial ischemia-related disorders constitute a major health problem, being a leading cause of death in the world. Upon ischemia, tissue remodeling processes come into play, comprising a series of inter-dependent stages, including inflammation, cell proliferation and repair. Neovessel formation during late phases of remodeling provides oxygen supply, together with cellular and soluble components necessary for an efficient myocardial reconstruction. Immune system plays a central role in processes aimed at repairing ischemic myocardium, mainly in inflammatory and angiogenesis phases. In addition to cellular components and soluble mediators as chemokines and cytokines, the immune system acts in a paracrine fashion through small extracellular vesicles (EVs) release. These vesicular structures participate in multiple biological processes, and transmit information through bioactive cargoes from one cell to another. Cell therapy has been employed in an attempt to improve the outcome of these patients, through the promotion of tissue regeneration and angiogenesis. However, clinical trials have shown variable results, which put into question the actual applicability of cell-based therapies. Paracrine factors secreted by engrafted cells partially mediate tissue repair, and this knowledge has led to the hypothesis that small EVs may become a useful tool for cell-free myocardial infarction therapy. Current small EVs engineering strategies allow delivery of specific content to selected cell types, thus revealing the singular properties of these vesicles for myocardial ischemia treatment.

Ischemic diseases, such as peripheral artery disease, affect millions of people worldwide. While CD4 + T-cells regulate angiogenesis and myogenesis, it is not understood how the phenotype of these adaptive immune cells regulate these regenerative processes. The secreted factors from different types of CD4 + T-cells (Th1, Th2, Th17, and Treg) were utilized in a series of in vitro assays and delivered from an injectable alginate biomaterial into a murine model of ischemia to study their effects on vascular and skeletal muscle regeneration. Conditioned medium from Th2 and Th17  T-cells enhanced angiogenesis in vitro and in vivo, in part by directly stimulating endothelial sprouting. Th1 conditioned medium induced vascular regression in vitro and provided no benefit to angiogenesis in vivo. Th1, Th2, and Th17 conditioned medium, to varying extents, enhanced muscle precursor cell proliferation and inhibited their differentiation in vitro, and prolonged early stages of muscle regeneration in vivo. Treg conditioned medium had a moderate or no effect on these processes in vitro and no discernible effect in vivo. These findings suggest that Th2 and Th17 T-cells may enhance angiogenesis and myogenesis in ischemic injuries, which may be useful in the design of immunomodulatory biomaterials to treat these diseases., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Introduction: Acute myocardial infarction (MI) is a primary cause of worldwide morbidity and mortality. Macrophages are fundamental components of post-MI inflammation. Pro-inflammatory macrophages can lead to adverse cardiac remodeling and heart failure while anti-inflammatory/reparative macrophages enhance tissue healing. Shifting the balance between pro-inflammatory and reparative macrophages post-MI is a novel therapeutic strategy. Azithromycin (AZM), a commonly used macrolide antibiotic, polarizes macrophages towards the anti-inflammatory phenotype, as shown in animal and human studies. We hypothesized that AZM modulates post-MI inflammation and improves cardiac recovery., Methods and Results: Male WT mice (C57BL/6, 6-8 weeks old) were treated with either oral AZM (160 mg/kg/day) or vehicle (control) starting 3 days prior to MI and continued to day 7 post-MI. We observed a significant reduction in mortality with AZM therapy. AZM-treated mice showed a significant decrease in pro-inflammatory (CD45+/Ly6G-/F4-80+/CD86+) and increase in anti-inflammatory (CD45+/Ly6G-/F4-80+/CD206+) macrophages, decreasing the pro-inflammatory/anti-inflammatory macrophage ratio in the heart and peripheral blood as assessed by flow cytometry and immunohistochemistry. Macrophage changes were associated with a significant decline in pro- and increase in anti-inflammatory cytokines. Mechanistic studies confirmed the ability of AZM to shift macrophage response towards an anti-inflammatory state under hypoxia/reperfusion stress. Additionally, AZM treatment was associated with a distinct decrease in neutrophil count due to apoptosis, a known signal for shifting macrophages towards the anti-inflammatory phenotype. Finally, AZM treatment improved cardiac recovery, scar size, and angiogenesis., Conclusion: Azithromycin plays a cardioprotective role in the early phase post-MI through attenuating inflammation and enhancing cardiac recovery. Post-MI treatment and human translational studies are warranted to examine the therapeutic applications of AZM., Competing Interests: The authors have declared that no competing interests exist.

Objective This study was performed to investigate the effect of Nocardia rubra cell wall skeleton (N-CWS) on wound healing of full-thickness skin defects. Methods Two 2- × 2-cm full-thickness wounds, one on each side of the midline, were made on the back of 12 rats. One wound was covered with Vaseline gauze soaked in normal saline, whereas the other was covered with Vaseline gauze and N-CWS. Wound dressings were changed every other day from day 0 (wound creation) to day 11. Four of the 12 rats were killed on day 7, and biopsy samples were obtained for biochemical and histopathological analyses. The expression levels of CD31, CD68, and F4/80 in the tissues were examined immunohistologically. The expression of transforming growth factor (TGF)-β1 in the wound was determined by western blot. Results N-CWS increased the wound healing rate, reduced the complete wound healing time, and increased the expression levels of CD31, CD68, and F4/80 on day 7. The TGF-β1 expression level in the wound was significantly higher in the N-CWS group than in the control group on day 7. Conclusions N-CWS can activate macrophages, increase TGF-β1 expression, and enhance angiogenesis and thus accelerate cutaneous wound healing.

Aging is associated with elevated cardiovascular disease risk. As a result of aging, endothelial dysfunction develops, partly due to a reduction in vascular regenerative ability. CD31 + T cells (angiogenic T cells; T ANG ) possess highly angiogenic capabilities; however, these cells are significantly reduced in older populations. In addition, older populations possess significantly higher senescent and highly differentiated T-cell levels in circulation, and these are reported to be highly exercise responsive. We investigated whether older adults display greater levels of circulating senescent (CD28 null ) T ANG cells and whether these cells were more exercise responsive than CD28 + T ANG cells. Young (18-25 years; n = 9) and older (60-75 years; n = 10) healthy men undertook a 30-min cycling bout at 70% V˙O 2 peak, with circulating T ANG cells (CD3 +  CD31 +  CD28 +/null ; including CD4 + and CD8 + subsets) measured preexercise, postexercise, and 1 h post exercise by flow cytometry. Older adults displayed reduced basal levels of T ANG cells (mean ± SEM: 410 ± 81 vs. 784 ± 118 cells·μL, P = 0.017), despite a greater proportion of these cells being CD28 null (26.26 ± 5.08 vs. 13.36 ± 2.62%, P = 0.044). Exercise significantly increased the circulating number of T ANG cells in both young and older men. However, in older men alone, exercise preferentially mobilized CD28 null CD8 + T ANG cells compared with CD28 + T ANG cells (time × phenotype interaction: P = 0.022; Δ74 ± 29 vs. Δ27 ± 15 cells·μL, P = 0.059), with no such difference observed between these phenotypes in the young population. In conclusion, this is the first study to demonstrate that despite observing lower circulating numbers of T ANG cells, older adults display greater levels of senescent T ANG cells in comparison with younger individuals, and these cells are more exercise responsive than CD28 + T ANG cells. Lower number of circulating T ANG and greater levels of senescent-associated CD28 null T ANG may contribute to greater CVD risk with advancing age., (© 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.)

The C-type lectin-like domain of CLEC14a (CLEC14a-C-type lectin-like domain [CTLD]) is a key domain that mediates endothelial cell-cell contacts in angiogenesis. However, the role of CLEC14a-CTLD in pathological angiogenesis has not yet been clearly elucidated. In this study, through complementarity-determining region grafting, consecutive deglycosylation, and functional isolation, we generated a novel anti-angiogenic human monoclonal antibody that specifically targets CLEC14a-CTLD and that shows improved stability and homogeneity relative to the parental antibody. We found that this antibody directly inhibits CLEC14a-CTLD-mediated endothelial cell-cell contact and simultaneously downregulates expression of CLEC14a on the surface of endothelial cells. Using various in vitro and in vivo functional assays, we demonstrated that this antibody effectively suppresses vascular endothelial growth factor (VEGF)-dependent angiogenesis and tumor angiogenesis of SNU182 human hepatocellular carcinoma, CFPAC-1 human pancreatic cancer, and U87 human glioma cells. Furthermore, we also found that this antibody significantly inhibits tumor angiogenesis of HCT116 and bevacizumab-adapted HCT116 human colorectal cancer cells. These findings suggest that antibody targeting of CLEC14a-CTLD has the potential to suppress VEGF-dependent angiogenesis and tumor angiogenesis and that CLEC14a-CTLD may be a novel anti-angiogenic target for VEGF-dependent angiogenesis and tumor angiogenesis., (© 2018 The Authors. Published by FEBS Press and John Wiley & Sons Ltd.)

In addition to accumulation and metabolism of triglycerides, white adipose tissue is recognized as the active endocrine organ, whose dysfunction is associated with the development of a wide range of diseases. The secretome of adipocytes is represented by a wide range of adipokines, which vary in depot and sex-specific manner. In addition, adipokines have diverse biological effects, correlations with different metabolic features and functions. In this review, the data on biological effects, origin and the clinical significance of adipokines are discussed. The influence of adipokines on metabolism, sensitivity to insulin, vascular homeostasis, angiogenesis, repair, inflammation and immune cells are shown. Visceral adipose tissue accumulation is accompanied with adipocytes hypertrophy and overproduction of such proinflammatory and proaterogenic molecules like resistin, visfatin, vaspin, tumor necrosis factor, interleukin 6, lipocalin, glypican 4, RBP4 etc. There is a tight correlation between these adipokines level and development of insulin resistance, type 2 diabetes, cardiometabolic complications and cancer. Thus, adipokines represent a group of informative biomarkers for the diagnostics of metabolic disorders and the prediction of the outcome of the wide range of diseases. The study of the effects and mechanisms of the action of adipokines is the basis for determining new targets for therapy.

Background: Tendinopathy of the long head of the biceps brachii tendon (LHBT) is one of the most common, painful conditions of the anterior part of the shoulder and often coexists with rotator cuff tears. Multifactorial aetiopathology of tendi-nopathy is poorly understood; however, several studies indicated that it is seen predominantly in areas with decreased vascularity of the tissue; the pathology is also characterised by expansive and abundant neovascular in-growth. The aim of the study was to investigate the relationship between the neovascularisation of proximal part of the LHBT and pain along the bicipital groove., Materials and Methods: Tissue material was obtained from 28 patients who underwent a shoulder arthroscopy and experienced pain along the bicipital groove measured using Visual-Analog Scale (VAS) score. CD31 and CD34 molecules were visualised by immunohistochemical method to assess biceps tendon neovascula-risation and quantify it based on a Bonar scoring system., Results: Although all patients reported pain prior to arthroscopy (mean VAS score was 7.5), microscopic examination did not reveal neovascularisation in all cases. Immunohistochemical staining for CD31 and CD34 allowed for very precise visualisation and quantification of neovascularisation; however there was also no correlation between vessels in-growth scores and pain., Conclusions: The obtained data suggest that neovascularisation process in tendino-pathy is not directly related to pain; however, further studies are needed to explain its significance in the LHBT tendinopathy. (Folia Morphol 2018; 77, 2: 378-385).

Neutrophils have been implicated as harmful cells in a variety of inappropriate inflammatory conditions where they injure the host, leading to the death of the neutrophils and their subsequent phagocytosis by monocytes and macrophages. Here we show that in a fully repairing sterile thermal hepatic injury, neutrophils also penetrate the injury site and perform the critical tasks of dismantling injured vessels and creating channels for new vascular regrowth. Upon completion of these tasks, they neither die at the injury site nor are phagocytosed. Instead, many of these neutrophils reenter the vasculature and have a preprogrammed journey that entails a sojourn in the lungs to up-regulate CXCR4 (C-X-C motif chemokine receptor 4) before entering the bone marrow, where they undergo apoptosis., (Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Background: Hematopoietic stem cells (HSCs) promote fat graft survival by modulating its revascularization. The authors hypothesize that mobilization of HSCs by G-CSF will improve fat graft survival. Hence, we evaluated the effect of different doses of G-CSF on fat grafting., Methods: Male 8-week-old C57 mice received high-dose G-CSF (100 μg/kg), low-dose G-CSF (10 μg/kg), and PBS (control) intraperitoneally for 7 consecutive days right after autologous fat grafting. Grafted fat was harvested at 1, 4, and 12 weeks for examination., Results: The low-dose G-CSF, high-dose G-CSF, and control groups had retention rates of 73.6% ± 3.1%, 51.6% ± 4.4%, and 44.5% ± 4.0%, respectively, at 12 weeks (low-dose G-CSF versus control and low-dose G-CSF versus high-dose G-CSF, both p < 0.05; no significant difference between high-dose G-CSF and control group). Both doses of G-CSF successfully mobilized HSCs into circulation and upregulated the level of blood-derived stem cells in fat grafts, contributing to improved angiogenesis. However, high-dose G-CSF caused a prolonged macrophage infiltration and elevated level of inflammation (IL-6 and TNF-α), which led to severe fibrosis and impaired adipogenesis (downregulated expression of PPAR-γ and CEBP-α)., Conclusions: Low-dose G-CSF treatment successfully improved fat graft survival by mobilizing HSCs and inducing angiogenesis. However, high-dose G-CSF prolonged inflammation and caused severe fibrosis, leading to impaired adipogenesis and poor fat graft survival., (Copyright © 2017. Published by Elsevier Inc.)

Angiogenesis, the growth of new blood vessels, is a complex process requiring the orchestration of numerous different cell types, growth factors, and chemokines. Some of the recently acknowledged actors in this process are immune cells. They accumulate at hypoxic sites, but the kinetics, dynamics, and regulation of that trafficking are unknown. In this study, we used intravital and live cell imaging to understand how neutrophils and macrophages migrate and behave at angiogenic sites. We developed two reproducible models of angiogenesis: one by transplanting isolated and hypoxic pancreatic islets into the cremaster muscles of mice, and another by in vitro coculturing of mouse aortic rings with neutrophils. In vivo imaging of the hypoxic site revealed recruitment of neutrophils and macrophages, which occurred in parallel, with depletion of one subset not affecting the accumulation of the other. We found, by cell tracking and statistical analyses, that neutrophils migrated in a directional manner to "angiogenic hotspots" around the islet where endothelial sprouting occurs, which was confirmed in the in vitro model of angiogenesis and is dependent on CXCL12 signaling. Intimate interactions between neutrophils and neovessels were prevalent, and neutrophil depletion greatly hampered vessel growth. Macrophages were less motile and attained supportive positions around the neovessels. Here, we present two novel in vivo and in vitro imaging models to study leukocyte behavior and actions during angiogenesis. These models unveiled that neutrophil migration at a hypoxic site was guided by signals emanating from sprouting endothelium where these immune cells gathered at "angiogenic hotspots" at which vascular growth occurred., (© Society for Leukocyte Biology.)

Mesenchymal stem cells (MSCs) play an important role in regulating angiogenesis and immune balance. The abnormal MSCs in proliferation and function were reported at maternal fetal interface in patients with pre-eclampsia (PE). Long non-coding RNA MALAT1 was known to regulate the function of trophoblast cells. However, it is not clear whether MALAT1 regulates MSCs to be related to PE. In the present study, we found that the expression of MALAT1 was significantly reduced in both umbilical cord tissues and MSCs in patients with severe PE. MALAT1 did not affect the phenotype and differentiation of MSCs. Of note, transfection with MALAT1 plasmid into MSCs drove the cell cycle into G2/M phase and inhibited cell apoptosis. The supernatants from MALAT1-overexpressed MSCs promoted the migration of MSCs, invasion of HTR-8/SVneo and tube formation of HUVEC, while si-MALAT1 had the opposite effects. Moreover, we found that MALAT1-induced VEGF mediated these effects of MALAT1 on MSCs. Furthermore, we found that MALAT1-overexpressed MSCs promoted M2 macrophage polarization and this effect was mediated by MALAT1-induced IDO expression, suggesting that MALAT1 may enhance the immunosuppressive properties of MSCs in vivo. In addition, we also investigated the factors that inhibit MALAT1 expression in PE and found that peroxide was a cause for MALAT1 downregulation. Taken together, our data demonstrate that MALAT1 is an important endogenous regulator in the proliferation, angiogenesis, and immunosuppressive properties of MSCs, suggesting it may be involved in the pathogenesis of PE. J. Cell. Biochem. 118: 2780-2791, 2017. © 2017 Wiley Periodicals, Inc., (© 2017 Wiley Periodicals, Inc.)

Hypertension during pregnancy is the most common medical condition encountered during gestation. Despite this, knowledge of the mechanisms that underlie the disease and the development of new therapies are limited. Hypertension during pregnancy and some forms of cancer confer an increased risk to the development of cardiovascular disease later in life; one mechanism which may link these conditions is the involvement of natural killer (NK) cells. Whilst immunology and immunotherapy are well-developed areas in oncology; the complex mechanisms of the immune system in health and disease at the maternal-fetal interface are less well-defined. Natural killer (NK) cells have emerged as key immune cells involved in physiology and pathology of pregnancy. These small lymphocytes are present in the decidua (the uterine-specific uNK cells) and are distinct from peripheral NK cells. The uNK cell population plays a vital role in mediating trophoblast invasion and affecting decidual vascular remodelling whereas the role of the peripheral NK cell population during pregnancy is less well-defined. This review will give an overview of NK cell biology followed by a discussion of the current evidence for the role of uterine and peripheral NK cells at the maternal-fetal interface in health and disease. Furthermore, examples of NK cell research from cancer biology will be employed to inform future directions of research. By combining this knowledge from oncology where the field of immunotherapy has now matured into clinical trials; it is hopeful that new mechanisms can be elucidated to generate targets for similar therapeutic strategies for women with hypertensive pregnancies where interventions are needed., (Copyright © 2017. Published by Elsevier Ltd.)

Controlled revascularization and inflammation are key elements regulating endogenous regeneration after (bone) tissue trauma. Peripheral blood-derived cell subsets, such as regulatory T-helper cells and circulating (endothelial) progenitor cells, respectively, can support endogenous tissue healing, whereas effector T cells that are associated with an aged immune system can hinder bone regeneration. CD31 is expressed by diverse leukocytes and is well recognized as a marker of circulating endothelial (precursor) cells; however, CD31 is absent from the surface of differentiated effector T cells. Thus, we hypothesized that by separating the inhibitory fractions from the supportive fractions of circulating cells within the peripheral blood (PB) using the CD31 marker, bone regeneration in biologically compromised conditions, such as those observed in aged patients, could be improved. In support of our hypothesis, we detected an inverse correlation between CD31+ cells and effector T cells in the hematomas of human fracture patients, dependent on the age of the patient. Furthermore, we demonstrated the regenerative capacity of human PB-CD31+ cells in vitro. These findings were translated to a clinically relevant rat model of impaired bone healing. The transplantation of rat PB-CD31+ cells advanced bone tissue restoration in vivo and was associated with an early anti-inflammatory response, the stimulation of (re)vascularization, and reduced fibrosis. Interestingly, the depletion or enrichment of the highly abundant CD31+/14+ monocytes from the mixed CD31+ cell population diminished tissue regeneration at different levels, suggesting combined effects within the PB-CD31+ subsets. In summary, an intraoperative enrichment of PB-CD31+ cells might be a novel option to facilitate endogenous regeneration under biologically impaired situations by supporting immunomodulation and vascularization. © 2016 American Society for Bone and Mineral Research., (© 2016 American Society for Bone and Mineral Research.)

Blockade of angiogenesis can retard tumour growth, but may also paradoxically increase metastasis. This paradox may be resolved by vessel normalization, which involves increased pericyte coverage, improved tumour vessel perfusion, reduced vascular permeability, and consequently mitigated hypoxia. Although these processes alter tumour progression, their regulation is poorly understood. Here we show that type 1 T helper (T H 1) cells play a crucial role in vessel normalization. Bioinformatic analyses revealed that gene expression features related to vessel normalization correlate with immunostimulatory pathways, especially T lymphocyte infiltration or activity. To delineate the causal relationship, we used various mouse models with vessel normalization or T lymphocyte deficiencies. Although disruption of vessel normalization reduced T lymphocyte infiltration as expected, reciprocal depletion or inactivation of CD4 + T lymphocytes decreased vessel normalization, indicating a mutually regulatory loop. In addition, activation of CD4 + T lymphocytes by immune checkpoint blockade increased vessel normalization. T H 1 cells that secrete interferon-γ are a major population of cells associated with vessel normalization. Patient-derived xenograft tumours growing in immunodeficient mice exhibited enhanced hypoxia compared to the original tumours in immunocompetent humans, and hypoxia was reduced by adoptive T H 1 transfer. Our findings elucidate an unexpected role of T H 1 cells in vasculature and immune reprogramming. T H 1 cells may be a marker and a determinant of both immune checkpoint blockade and anti-angiogenesis efficacy.

Background: In order to identify factors that stimulate arteriogenesis after ischemia, we followed gene expression profiles in two extreme models for collateral artery formation over 28 days after hindlimb ischemia, namely "good-responding" C57BL/6 mice and "poor-responding" BALB/c mice., Methods and Results: Although BALB/c mice show very poor blood flow recovery after ischemia, most known proarteriogenic genes were upregulated more excessively and for a longer period than in C57BL/6 mice. In clear contrast, chemokine genes Ccl19 , Ccl21a , and Ccl21c and the chemokine receptor CCR7 were upregulated in C57BL/6 mice 1 day after hindlimb ischemia, but not in BALB/C mice. CCL19 and CCL21 regulate migration and homing of T lymphocytes via CCR7. When subjecting CCR7 -/- /LDLR -/- mice to hindlimb ischemia, we observed a 20% reduction in blood flow recovery compared with that in LDLR -/- mice. Equal numbers of α-smooth muscle actin-positive collateral arteries were found in the adductor muscles of both mouse strains, but collateral diameters were smaller in the CCR7 -/- /LDLR -/- . Fluorescence-activated cell sorter analyses showed that numbers of CCR7 + T lymphocytes (both CD4 + and CD8 + ) were decreased in the spleen and increased in the blood at day 1 after hindlimb ischemia in LDLR -/- mice. At day 1 after hindlimb ischemia, however, numbers of activated CD4 + T lymphocytes were decreased in the draining lymph nodes of LDLR -/- mice compared with CCR7 -/- /LDLR -/- mice., Conclusions: These data show that CCR7-CCL19/CCL21 axis facilitates retention CD4 + T lymphocytes at the site of collateral artery remodeling, which is essential for effective arteriogenesis., (© 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

Background: New vessels are formed in response to stimuli from angiogenic factors, a process in which paracrine signaling is fundamental., Objective: To investigate the cooperative paracrine signaling profile in response to Vascular Endothelial Growth Factor (VEGF) gene therapy in patients with coronary artery disease (CAD) and refractory angina., Method: A cohort study was conducted in which plasma was collected from patients who underwent gene therapy with a plasmid expressing VEGF 165 (10) and from surgical procedure controls (4). Blood samples were collected from both groups prior to baseline and on days 3, 9 and 27 after the interventions and subjected to systemic analysis of protein expression (Interleukin-6, IL-6; Tumor Necrosis Factor-α, TNF-α; Interleukin-10, IL-10; Stromal Derived Factor-1 α, SDF-1α; VEGF; Angiopoietin-1, ANGPT-1; and Endothelin-1, ET-1) using the enzyme-linked immunosorbent assay (ELISA)., Results: Analysis showed an increase in proinflammatory IL-6 (p=0.02) and ET-1 (p=0.05) on day 3 after gene therapy and in VEGF (p=0.02) on day 9. A strong positive correlation was found between mobilization of endothelial progenitor cells and TNF-α on day 9 (r=0.71; p=0.03). Furthermore, a strong correlation between β-blockers, antiplatelets, and vasodilators with SDF-1α baseline in the group undergoing gene therapy was verified (r=0.74; p=0.004)., Conclusion: Analysis of cooperative paracrine signaling after VEGF gene therapy suggests that the immune system cell and angiogenic molecule expression as well as the endothelial progenitor cell mobilization are time-dependent, influenced by chronic inflammatory process and continuous pharmacological treatment., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Macrophages and Wnt proteins (Wnts) are independently involved in cardiac development, response to cardiac injury, and repair. However, the role of macrophage-derived Wnts in the healing and repair of myocardial infarction (MI) is unknown. We sought to determine the role of macrophage Wnts in infarct repair., Methods and Results: We show that the Wnt pathway is activated after MI in mice. Furthermore, we demonstrate that isolated infarct macrophages express distinct Wnt pathway components and are a source of noncanonical Wnts after MI. To determine the effect of macrophage Wnts on cardiac repair, we evaluated mice lacking the essential Wnt transporter Wntless (Wls) in myeloid cells. Significantly, Wntless-deficient macrophages presented a unique subset of M2-like macrophages with anti-inflammatory, reparative, and angiogenic properties. Serial echocardiography studies revealed that mice lacking macrophage Wnt secretion showed improved function and less remodeling 30 days after MI. Finally, mice lacking macrophage-Wntless had increased vascularization near the infarct site compared with controls., Conclusions: Macrophage-derived Wnts are implicated in adverse cardiac remodeling and dysfunction after MI. Together, macrophage Wnts could be a new therapeutic target to improve infarct healing and repair., (© 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

There are three dominant contributors to the pathogenesis of dysfunctional adipose tissue (AT) in obesity: unresolved inflammation, inappropriate extracellular matrix (ECM) remodeling and insufficient angiogenic potential. The interactions of these processes during AT expansion reflect both a linear progression as well as feed-forward mechanisms. For example, both inflammation and inadequate angiogenic remodeling can drive fibrosis, which can in turn promote migration of immune cells into adipose depots and impede further angiogenesis. Therefore, the relationship between the members of this triad is complex but important for our understanding of the pathogenesis of obesity. Here we untangle some of these intricacies to highlight the contributions of inflammation, angiogenesis, and the ECM to both "healthy" and "unhealthy" AT expansion., Competing Interests: The authors have declared that no conflict of interest exists.

The period of forming of superficial vascular plexus during physiological retinal angiogenesis was shorter in C57Bl/6 mice. Experiments on the model of oxygen-induced retinopathy showed that avascular and vascularized zones in BALB/c mice on day 17 are smaller than in C57Bl/6 mice are by 5 and 1.5 times, respectively. The obtained results confirmed the importance of phenotype of retinal macrophages in the regulation of processes of both physiological and pathological retinal angiogenesis.

Autologous fat grafting is an effective reconstructive surgery technique; however, its success is limited by inconsistent graft retention and an environment characterized by high oxidative stress and inflammation. Adipose-derived stem cells (ADSCs) increase the survival of fat grafts, although the underlying mechanisms remain unclear. Here, TLR4(-/-) and Nrf2(-/-) mice were used to explore the effects of oxidative stress and inflammation on the viability and function of ADSCs in vitro and in vivo. Enrichment of fat grafts with ADSCs inhibited inflammatory cytokine production, enhanced growth factor levels, increased fat graft survival, downregulated NADPH oxidase (NOX)1 and 4 expression, increased vascularization and reduced ROS production in a manner dependent on toll-like receptor (TLR)-4 and nuclear factor erythroid 2-related factor 2 (Nrf2) expression. Immunohistochemical analysis showed that exposure to hypoxia enhanced ADSC growth and promoted the differentiation of ADSCs into vascular endothelial cells. Hypoxia-induced inflammatory cytokine, growth factor and NOX1/4 upregulation, as well as increased ROS production and apoptosis in ADSCs were dependent on TLR4 and Nrf2, which also modulated the effect of ADSCs on promoting endothelial progenitor cell migration and angiogenesis. Western blot analyses showed that the effects of hypoxia on ADSCs were regulated by crosstalk between Nrf2 antioxidant responses and NF-κB- and TLR4-mediated inflammatory responses. Taken together, our results indicate that ADSCs can increase the survival of fat transplants through the modulation of inflammatory and oxidative responses via Nrf2 and TLR4, suggesting potential strategies to improve the use of ADSCs for cell therapy.

Mitogenicity is the ability of the natural or synthetic compounds to induce cell division or proliferation. A series of salicylic acid derivatives containing isoxazoline moiety (8a-j) were synthesized and their immunopharmacological activities targeting lymphocyte proliferation and angiogenesis were evaluated. The compounds 8a-j mitogenicity were investigated on immunological cells that include human peripheral blood lymphocytes and murine splenocytes in-vitro. The results implicate that among the series of 8a-j, compound 8e showed a potent proliferative response on both human and murine lymphocytes. The proliferative index of the compound 8e was comparable to the reference mitogen Con A and mitogenecity is due to increased secretion IL-2. In -vivo CAM and rat corneal angiogenesis assays were performed to assess the compound's effect on endothelial cell migration and proliferation which inferred that 8e also induces the proliferation of endothelial cells. The study reports the synthetic immunostimulatory and pro-angiogenic activity of novel mitogen 8e which could be translated into new drug in future., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)