Scavenger receptors in homeostasis and immunity
TL;DR: This Review highlights recent insights into the structural features that determine the function of scavenger receptors and the emerging role that these receptors have in immune responses, notably in macrophage polarization and in the pathogenesis of diseases such as atherosclerosis and Alzheimer's disease.
Abstract: Scavenger receptors were originally identified by their ability to recognize and to remove modified lipoproteins; however, it is now appreciated that they carry out a striking range of functions, including pathogen clearance, lipid transport, the transport of cargo within the cell and even functioning as taste receptors. The large repertoire of ligands recognized by scavenger receptors and their broad range of functions are not only due to the wide range of receptors that constitute this family but also to their ability to partner with various co-receptors. The ability of individual scavenger receptors to associate with different co-receptors makes their responsiveness extremely versatile. This Review highlights recent insights into the structural features that determine the function of scavenger receptors and the emerging role that these receptors have in immune responses, notably in macrophage polarization and in the pathogenesis of diseases such as atherosclerosis and Alzheimer's disease.
Citations
More filters
TL;DR: This review focuses on describing macrophage-based initiation of downstream hallmark immunological and inflammatory processes resulting from phagocyte exposure to and internalization of nanomaterials.
882 citations
Liverpool School of Tropical Medicine1, University of Liverpool2, Queen Mary University of London3, Harvard University4, University of Oxford5, University of Birmingham6, Columbia University7, Sri Ramachandra University8, University of California, Berkeley9, University of California, San Francisco10, Malawi-Liverpool-Wellcome Trust Clinical Research Programme11, Johns Hopkins University12, Oregon Health & Science University13, Fudan University14, Health Effects Institute15, University of Georgia16, University of Aberdeen17, Ohio State University18
TL;DR: Evidence for the association between household air pollution and respiratory infections, respiratory tract cancers, and chronic lung diseases is reviewed, as well as study design issues and potential effective interventions to prevent these disease burdens.
672 citations
TL;DR: This review introduces basic immunological concepts required to understand the mechanisms that rule the potential claimed immunostimulatory activity of polysaccharides and critically presents a literature survey on the structural features of the poly Saccharide and reported immunostIMulatory activity.
664 citations
TL;DR: A variety of current approaches for enhancing the delivery of oligonucleotides including molecular scale targeted ligand-oligonucleotide conjugates, lipid- and polymer-based nanoparticles, antibody conjugate and small molecules that improve oligon nucleotide delivery are examined.
Abstract: The oligonucleotide therapeutics field has seen remarkable progress over the last few years with the approval of the first antisense drug and with promising developments in late stage clinical trials using siRNA or splice switching oligonucleotides. However, effective delivery of oligonucleotides to their intracellular sites of action remains a major issue. This review will describe the biological basis of oligonucleotide delivery including the nature of various tissue barriers and the mechanisms of cellular uptake and intracellular trafficking of oligonucleotides. It will then examine a variety of current approaches for enhancing the delivery of oligonucleotides. This includes molecular scale targeted ligand-oligonucleotide conjugates, lipid- and polymer-based nanoparticles, antibody conjugates and small molecules that improve oligonucleotide delivery. The merits and liabilities of these approaches will be discussed in the context of the underlying basic biology.
609 citations
Cites background from "Scavenger receptors in homeostasis ..."
...This cohort of transmembrane receptors constitutes a functional family rather than one demarcated by common sequence or structure (59,113)....
[...]
TL;DR: The past century has brought improved tools of cellular and molecular biology to the study of phagocytosis and its contribution to physiological and pathological processes, including receptor function in innate and acquired immunity.
538 citations
Cites background from "Scavenger receptors in homeostasis ..."
...Crohn’s disease, for example, has a genetic component involving Nod-like receptors and autophagy (Caruso et al., 2014)....
[...]
References
More filters
TL;DR: This Review suggests a new grouping of macrophages based on three different homeostatic activities — host defence, wound healing and immune regulation, and proposes that similarly to primary colours, these three basic macrophage populations can blend into various other 'shades' of activation.
Abstract: Macrophages display remarkable plasticity and can change their physiology in response to environmental cues. These changes can give rise to different populations of cells with distinct functions. In this Review we suggest a new grouping of macrophage populations based on three different homeostatic activities - host defence, wound healing and immune regulation. We propose that similarly to primary colours, these three basic macrophage populations can blend into various other 'shades' of activation. We characterize each population and provide examples of macrophages from specific disease states that have the characteristics of one or more of these populations.
7,384 citations
TL;DR: These functionally polarized cells, and similarly oriented or immature dendritic cells present in tumors, have a key role in subversion of adaptive immunity and in inflammatory circuits that promote tumor growth and progression.
4,728 citations
TL;DR: The identification of mechanisms and molecules associated with macrophage plasticity and polarized activation provides a basis for Macrophage-centered diagnostic and therapeutic strategies.
Abstract: Diversity and plasticity are hallmarks of cells of the monocyte-macrophage lineage. In response to IFNs, Toll-like receptor engagement, or IL-4/IL-13 signaling, macrophages undergo M1 (classical) or M2 (alternative) activation, which represent extremes of a continuum in a universe of activation states. Progress has now been made in defining the signaling pathways, transcriptional networks, and epigenetic mechanisms underlying M1-M2 or M2-like polarized activation. Functional skewing of mononuclear phagocytes occurs in vivo under physiological conditions (e.g., ontogenesis and pregnancy) and in pathology (allergic and chronic inflammation, tissue repair, infection, and cancer). However, in selected preclinical and clinical conditions, coexistence of cells in different activation states and unique or mixed phenotypes have been observed, a reflection of dynamic changes and complex tissue-derived signals. The identification of mechanisms and molecules associated with macrophage plasticity and polarized activation provides a basis for macrophage-centered diagnostic and therapeutic strategies.
4,721 citations
TL;DR: It is shown that the class B scavenger receptor SR-BI is an HDL receptor, which mediates selective cholesterol uptake by a mechanism distinct from the classic LDL receptor pathway.
Abstract: High density lipoprotein (HDL) and low density lipoprotein (LDL) are cholesterol transport particles whose plasma concentrations are directly (LDL) and inversely (HDL) correlated with risk for atherosclerosis. LDL catabolism involves cellular uptake and degradation of the entire particle by a well-characterized receptor. HDL, in contrast, selectively delivers its cholesterol, but not protein, to cells by unknown receptors. Here it is shown that the class B scavenger receptor SR-BI is an HDL receptor. SR-BI binds HDL with high affinity, is expressed primarily in liver and nonplacental steroidogenic tissues, and mediates selective cholesterol uptake by a mechanism distinct from the classic LDL receptor pathway.
2,315 citations
TL;DR: The innate immune system evolved several strategies of self/nonself discrimination that are based on the recognition of molecular patterns demarcating infectious nonself, as well as normal and abnormal self.
Abstract: The innate immune system evolved several strategies of self/nonself discrimination that are based on the recognition of molecular patterns demarcating infectious nonself, as well as normal and abnormal self. These patterns are deciphered by receptors that either induce or inhibit an immune response, depending on the meaning of these signals.
2,093 citations