Live-cell visualization of the trans-cellular mode of monocyte transmigration across the vascular endothelium, and its relationship with endothelial PECAM-1

The effects of glycosylation modifications on monocyte recruitment and foam cell formation in atherosclerosis

The monocyte recruitment and foam cell formation have been intensively investigated in atherosclerosis. Nevertheless, as the study progressed, it was obvious that crucial molecules participated in the monocyte recruitment and the membrane proteins in macrophages exhibited substantial glycosylation modifications. These modifications can exert a significant influence on protein functions and may even impact the overall progression of diseases. This article provides a review of the effects of glycosylation modifications on monocyte recruitment and foam cell formation. By elaborating on these effects, we aim to understand the underlying mechanisms of atherogenesis further and to provide new insights into the future treatment of atherosclerosis.

Research progress on the active ingredients of traditional Chinese medicine in the intervention of atherosclerosis: A promising natural immunotherapeutic adjuvant

Atherosclerosis (AS) is a chronic inflammatory disease caused by disorders of lipid metabolism. Abnormal deposition of low-density lipoproteins in the arterial wall stimulates the activation of immune cells, including the adhesion and infiltration of monocytes, the proliferation and differentiation of macrophages and lymphocytes, and the activation of their functions. The complex interplay between immune cells coordinates the balance between pro- and anti-inflammation and plays a key role in the progression of AS. Therefore, targeting immune cell activity may lead to the development of more selective drugs with fewer side effects to treat AS without compromising host defense mechanisms. At present, an increasing number of studies have found that the active ingredients of traditional Chinese medicine (TCM) can regulate the function of immune cells in multiple ways to against AS, showing great potential for the treatment of AS and promising clinical applications. In this paper, we review the mechanisms of immune cell action in AS lesions and the potential targets and/or pathways for immune cell regulation by the active ingredients of TCM to promote the understanding of the immune system interactions of AS and provide a relevant basis for the use of active ingredients of TCM as natural adjuvants for AS immunotherapy.

The Bone Marrow Microenvironment Mechanisms in Acute Myeloid Leukemia

Bone marrow (BM) is a highly complex tissue that provides important regulatory signals to orchestrate hematopoiesis. Resident and transient cells occupy and interact with some well characterized niches to produce molecular and cellular mechanisms that interfere with differentiation, migration, survival, and proliferation in this microenvironment. The acute myeloid leukemia (AML), the most common and severe hematological neoplasm in adults, arises and develop in the BM. The osteoblastic, vascular, and reticular niches provide surface co-receptors, soluble factors, cytokines, and chemokines that mediate important functions on hematopoietic cells and leukemic blasts. There are some evidences of how AML modify the architecture and function of these three BM niches, but it has been still unclear how essential those modifications are to maintain AML development. Basic studies and clinical trials have been suggesting that disturbing specific cells and molecules into the BM niches might be able to impair leukemia competencies. Either through niche-specific molecule inhibition alone or in combination with more traditional drugs, the bone marrow microenvironment is currently considered the potential target for new strategies to treat AML patients. This review describes the cellular and molecular constitution of the BM niches under healthy and AML conditions, presenting this anatomical compartment by a new perspective: as a prospective target for current and next generation therapies.

Variety matters: Diverse functions of monocyte subtypes in vascular inflammation and atherogenesis

Monocytes are important mediators of the innate immunity by recognizing and attacking especially bacterial pathogens but also play crucial roles in various inflammatory diseases, including vascular inflammation and atherosclerosis. Maturation, differentiation and function of monocytes have been intensively explored for a long time in innumerable experimental and clinical studies. Monocytes do not represent a uniform cell type but could be further subdivided into subpopulations with distinct features and functions. Those subpopulations have been identified in experimental mouse models as well as in humans, albeit distinguished by different cell surface markers. While Ly6C is used for subpopulation differentiation in mice, corresponding human subsets are differentiated by CD14 and CD16. In this review, we specifically focused on new experimental insights from recent years mainly in regard to murine monocyte subpopulations and their roles in vascular inflammation und atherogenesis.

Cryptotanshinone inhibits TNF-α-induced early atherogenic events in vitro

Endothelial dysfunction has been implicated in the pathogenesis of atherosclerosis. Salvia miltiorrhiza (danshen) is a traditional Chinese medicine that has been effectively used to treat cardiovascular disease. Cryptotanshinone (CTS), a major lipophilic compound isolated from S. miltiorrhiza, has been reported to possess cardioprotective effects. However, the anti-atherogenic effects of CTS, particularly on tumor necrosis factor-α (TNF-α)-induced endothelial cell activation, are still unclear. This study aimed to determine the effect of CTS on TNF-α-induced increased endothelial permeability, monocyte adhesion, soluble intercellular adhesion molecule 1 (sICAM-1), soluble vascular cell adhesion molecule 1 (sVCAM-1), monocyte chemoattractant protein 1 (MCP-1) and impaired nitric oxide production in human umbilical vein endothelial cells (HUVECs), all of which are early events occurring in atherogenesis. We showed that CTS significantly suppressed TNF-α-induced increased endothelial permeability, monocyte adhesion, sICAM-1, sVCAM-1 and MCP-1, and restored nitric oxide production. These observations suggest that CTS possesses anti-inflammatory properties and could be a promising treatment for the prevention of cytokine-induced early atherogenesis.

The Role of Chemokine and Glycosaminoglycan Interaction in Chemokine-Mediated Migration In Vitro and In Vivo

Chemokines have a range of functions, including the activation and promotion of the vectorial migration of leukocytes. They mediate their biological effects by binding to their cognate G-protein-coupled receptors. Upon activation of the heterotrimeric G proteins, the Gα subunit exchanges GDP for GTP and dissociates from the receptor and from the Gβγ subunits, and both G-protein complexes go on to activate other downstream signaling events. In addition, chemokines interact with cell-surface glycosaminoglycans (GAGs). This potential for binding GAG components of proteoglycans on the cell surface or within the extracellular matrix allows the formation of the stable chemokine gradients necessary for leukocyte chemotaxis. In this chapter, we describe techniques for studying chemotaxis both in vivo and in vitro, as well as the creation of chemokine receptor-expressing cell lines, in order to examine this process in isolation.

Monocyte trafficking across the vessel wall

Monocytes fundamentally contribute to immune surveillance and the inflammatory response in immunoinflammatory diseases like atherosclerosis. Recruitment of these cells to the site of injury requires their trafficking across the blood vessel wall. A series of events, including capture, rolling, slow rolling, arrest, adhesion strengthening, and lateral locomotion, precede monocyte transmigration. Recent investigations have revealed new aspects of this cascade. This article revisits some conventional paradigms and selectively highlights new findings, including novel insights into monocyte differentiation and recently identified functional mediators, signalling pathways, and new structural aspects of monocyte extravasation. The emerging roles of endothelial junctional molecules like vascular endothelial-cadherin and the junctional adhesion molecule family, adhesion molecules such as intercellular adhesion molecule-1, molecules localized to the lateral border recycling compartment like cluster of differentiation 99, platelet/endothelial cell adhesion molecule-1, and poliovirus receptor (CD155), as well as other cell surface molecules such as cluster of differentiation 146 and ephrins in transendothelial migration are discussed.

Assessing the barriers to image-guided drug delivery

Imaging has become a cornerstone for medical diagnosis and the guidance of patient management. A new field called image-guided drug delivery (IGDD) now combines the vast potential of the radiological sciences with the delivery of treatment and promises to fulfill the vision of personalized medicine. Whether imaging is used to deliver focused energy to drug-laden particles for enhanced, local drug release around tumors, or it is invoked in the context of nanoparticle-based agents to quantify distinctive biomarkers that could risk stratify patients for improved targeted drug delivery efficiency, the overarching goal of IGDD is to use imaging to maximize effective therapy in diseased tissues and to minimize systemic drug exposure in order to reduce toxicities. Over the last several years, innumerable reports and reviews covering the gamut of IGDD technologies have been published, but inadequate attention has been directed toward identifying and addressing the barriers limiting clinical translation. In this consensus opinion, the opportunities and challenges impacting the clinical realization of IGDD-based personalized medicine were discussed as a panel and recommendations were proffered to accelerate the field forward.

The involvement of the monocytes/macrophages in chronic inflammation associated with atherosclerosis

Atherosclerosis is a progressive chronic disease of large and medium arteries, characterized by the formation of atherosclerotic plaques. Monocytes and macrophages are key factors in lesion development, participating to the processes that mediate the progression of the atherosclerotic plaque (lipid accumulation, secretion of pro-inflammatory and cytotoxic factors, extracellular matrix remodeling). The recruitment of the monocytes in the vascular wall represents a hallmark in the pathology of the atherosclerotic lesion. Monocyte adhesion and transmigration are dependent on the complementary adhesion molecules expressed on the endothelial surface, whose expression is modulated by chemical mediators. The atherosclerotic plaque is characterized by a heterogeneous population of macrophages reflecting the complexity and diversity of the micro-environment to which cells are exposed after entering the arterial wall. Within the atherosclerotic lesions, macrophages differentiate, proliferate and undergo apoptosis. Taking into account that their behavior has a direct and critical influence on all lesional stages, the development of therapeutic approaches to target monocytes/macrophages in the atherosclerotic plaque became a focal interest point for researchers in the field.