scholarly journals Toll-Like Receptors, Their Ligands, and Atherosclerosis

2011 ◽  
Vol 11 ◽  
pp. 437-453 ◽  
Author(s):  
Conrad P. Hodgkinson ◽  
Shu Ye
Keyword(s):  
Arterial Wall ◽  
Cell Types ◽  
Innate Immune ◽  
Toll Like Receptors ◽  
Increased Risk ◽  
Inflammatory Proteins ◽  
Endogenous Proteins ◽  
Molecular Patterns ◽  
Microbial Agents

Atherosclerosis is a disease characterized by inflammation in the arterial wall. Atherogenesis is dependent on the innate immune response involving activation of Toll-like receptors (TLRs) and the expression of inflammatory proteins. TLRs, which recognize various pathogen-associated molecular patterns, are expressed in various cell types within the atherosclerotic plaque. Microbial agents are associated with an increased risk of atherosclerosis and this is, in part, due to activation of TLRs. Recently considerable evidence has been provided suggesting that endogenous proteins promote atherosclerosis by binding to TLRs. In this review, we describe the role of TLRs in atherosclerosis with particular emphasis on those atherogenic endogenous proteins that have been implicated as TLR ligands.

Role of Toll-like receptors in liver health and disease

2011 ◽  
Vol 121 (10) ◽  
pp. 415-426 ◽  
Author(s):  
Ruth Broering ◽  
Mengji Lu ◽  
Joerg F. Schlaak
Keyword(s):  
Immune System ◽  
Liver Disease ◽  
Innate Immune System ◽  
Innate Immune ◽  
Toll Like Receptors ◽  
Evolutionarily Conserved ◽  
Liver Health ◽  
Health And Disease ◽  
Molecular Patterns

TLRs (Toll-like receptors), as evolutionarily conserved germline-encoded pattern recognition receptors, have a crucial role in early host defence by recognizing so-called PAMPs (pathogen-associated molecular patterns) and may serve as an important link between innate and adaptive immunity. In the liver, TLRs play an important role in the wound healing and regeneration processes, but they are also involved in the pathogenesis and progression of various inflammatory liver diseases, including autoimmune liver disease, alcoholic liver disease, non-alcoholic steatohepatitis, fibrogenesis, and chronic HBV (hepatitis B virus) and HCV (hepatitis C virus) infection. Hepatitis viruses have developed different evading strategies to subvert the innate immune system. Thus recent studies have suggested that TLR-based therapies may represent a promising approach in the treatment in viral hepatitis. The present review focuses on the role of the local innate immune system, and TLRs in particular, in the liver.

scholarly journals Role of toll-like receptors in human iris pigment epithelial cells and their response to pathogen-associated molecular patterns

2014 ◽  
Vol 11 (1) ◽  
pp. 20 ◽  
Author(s):  
Kelly Mai ◽  
Jeanie JY Chui ◽  
Nick Di Girolamo ◽  
Peter J McCluskey ◽  
Denis Wakefield
Keyword(s):  
Epithelial Cells ◽  
Toll Like Receptors ◽  
Pigment Epithelial ◽  
Human Iris ◽  
Molecular Patterns ◽  
Pigment Epithelial Cells

scholarly journals Toll-Like Receptors and Myocardial Inflammation

2011 ◽  
Vol 2011 ◽  
pp. 1-21 ◽  
Author(s):  
Yan Feng ◽  
Wei Chao
Keyword(s):  
Animal Studies ◽  
Myocardial Injury ◽  
Myocardial Inflammation ◽  
Septic Cardiomyopathy ◽  
Toll Like Receptors ◽  
Tlr Signaling ◽  
Animal Data ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

Toll-like receptors (TLRs) are a member of the innate immune system. TLRs detect invading pathogens through the pathogen-associated molecular patterns (PAMPs) recognition and play an essential role in the host defense. TLRs can also sense a large number of endogenous molecules with the damage-associated molecular patterns (DAMPs) that are produced under various injurious conditions. Animal studies of the last decade have demonstrated that TLR signaling contributes to the pathogenesis of the critical cardiac conditions, where myocardial inflammation plays a prominent role, such as ischemic myocardial injury, myocarditis, and septic cardiomyopathy. This paper reviews the animal data on (1) TLRs, TLR ligands, and the signal transduction system and (2) the important role of TLR signaling in these critical cardiac conditions.

scholarly journals Osteoarthritis and Toll-Like Receptors: When Innate Immunity Meets Chondrocyte Apoptosis

Biology ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 65
Author(s):  
Goncalo Barreto ◽  
Mikko Manninen ◽  
Kari K. Eklund
Keyword(s):  
Inflammatory Responses ◽  
Critical Role ◽  
Innate Immune ◽  
Chondrocyte Apoptosis ◽  
Innate Immune Responses ◽  
Toll Like Receptors ◽  
Chondrocyte Death ◽  
Dominant Feature ◽  
Functional Relevance

Osteoarthritis (OA) has long been viewed as a degenerative disease of cartilage, but accumulating evidence indicates that inflammation has a critical role in its pathogenesis. In particular, chondrocyte-mediated inflammatory responses triggered by the activation of innate immune receptors by alarmins (also known as danger signals) are thought to be involved. Thus, toll-like receptors (TLRs) and their signaling pathways are of particular interest. Recent reports suggest that among the TLR-induced innate immune responses, apoptosis is one of the critical events. Apoptosis is of particular importance, given that chondrocyte death is a dominant feature in OA. This review focuses on the role of TLR signaling in chondrocytes and the role of TLR activation in chondrocyte apoptosis. The functional relevance of TLR and TLR-triggered apoptosis in OA are discussed as well as their relevance as candidates for novel disease-modifying OA drugs (DMOADs).

scholarly journals Role of Toll-Like Receptors in Actuating Stem/Progenitor Cell Repair Mechanisms: Different Functions in Different Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Fabio Sallustio ◽  
Claudia Curci ◽  
Alessandra Stasi ◽  
Giuseppe De Palma ◽  
Chiara Divella ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Therapeutic Potential ◽  
Toll Like Receptors ◽  
Repair Mechanisms ◽  
Specific Tissue ◽  
The Many ◽  
Pathological Environment ◽  
Molecular Patterns

Toll-like receptors (TLRs) represent one of the bridges that regulate the cross-talk between the innate and adaptive immune systems. TLRs interact with molecules shared and preserved by the pathogens of origin but also with endogenous molecules (damage/danger-associated molecular patterns (DAMPs)) that derive from injured tissues. This is probably why TLRs have been found to be expressed on several kinds of stem/progenitor cells (SCs). In these cells, the role of TLRs in the regulation of the basal motility, proliferation, differentiation processes, self-renewal, and immunomodulation has been demonstrated. In this review, we analyze the many different functions that the TLRs assume in SCs, pointing out that they can have different effects, depending on the background and on the kind of ligands that they recognize. Moreover, we discuss the TLR involvement in the response of SC to specific tissue damage and in the reparative processes, as well as how the identification of molecules mediating the differential function of TLR signaling could be decisive for the development of new therapeutic strategies. Considering the available studies on TLRs in SCs, here we address the importance of TLRs in sensing an injury by stem/progenitor cells and in determining their behavior and reparative activity, which is dependent on the conditions. Therefore, it could be conceivable that SCs employed in therapy could be potentially exposed to TLR ligands, which might modulate their therapeutic potential in vivo. In this context, to modulate SC proliferation, survival, migration, and differentiation in the pathological environment, we need to better understand the mechanisms of action of TLRs on SCs and learn how to control these receptors and their downstream pathways in a precise way. In this manner, in the future, cell therapy could be improved and made safer.

scholarly journals The Role of Peptide Signals Hidden in the Structure of Functional Proteins in Plant Immune Responses

2019 ◽  
Vol 20 (18) ◽  
pp. 4343 ◽  
Author(s):  
Irina Lyapina ◽  
Anna Filippova ◽  
Igor Fesenko
Keyword(s):  
Immune Responses ◽  
Defense Responses ◽  
Innate Immune ◽  
Functional Protein ◽  
Diverse Range ◽  
Peptide Signals ◽  
Plant Pathogen Interactions ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

Plants have evolved a sophisticated innate immune system to cope with a diverse range of phytopathogens and insect herbivores. Plasma-membrane-localized pattern recognition receptors (PRRs), such as receptor-like kinases (RLK), recognize special signals, pathogen- or damage-associated molecular patterns (PAMPs or DAMPs), and trigger immune responses. A growing body of evidence shows that many peptides hidden in both plant and pathogen functional protein sequences belong to the group of such immune signals. However, the origin, evolution, and release mechanisms of peptide sequences from functional and nonfunctional protein precursors, known as cryptic peptides, are largely unknown. Various special proteases, such as metacaspase or subtilisin-like proteases, are involved in the release of such peptides upon activation during defense responses. In this review, we discuss the roles of cryptic peptide sequences hidden in the structure of functional proteins in plant defense and plant-pathogen interactions.

scholarly journals The Role of Monocytes and Macrophages in Human Atherosclerosis, Plaque Neoangiogenesis, and Atherothrombosis

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Francesco Moroni ◽  
Enrico Ammirati ◽  
Giuseppe Danilo Norata ◽  
Marco Magnoni ◽  
Paolo G. Camici
Keyword(s):  
Animal Studies ◽  
Arterial Wall ◽  
Causes Of Death ◽  
Complex Disease ◽  
Potential Role ◽  
Innate Immune ◽  
Pathogenic Role ◽  
Monocytes And Macrophages ◽  
Human Atherosclerosis

Atherosclerosis is one of the leading causes of death and disability worldwide. It is a complex disease characterized by lipid accumulation within the arterial wall, inflammation, local neoangiogenesis, and apoptosis. Innate immune effectors, in particular monocytes and macrophages, play a pivotal role in atherosclerosis initiation and progression. Although most of available evidence on the role of monocytes and macrophages in atherosclerosis is derived from animal studies, a growing body of evidence elucidating the role of these mononuclear cell subtypes in human atherosclerosis is currently accumulating. A novel pathogenic role of monocytes and macrophages in terms of atherosclerosis initiation and progression, in particular concerning the role of these cell subsets in neovascularization, has been discovered. The aim of the present article is to review currently available evidence on the role of monocytes and macrophages in human atherosclerosis and in relation to plaque characteristics, such as plaque neoangiogenesis, and patients’ prognosis and their potential role as biomarkers.

scholarly journals Toll-Like Receptors in Angiogenesis

2011 ◽  
Vol 11 ◽  
pp. 981-991 ◽  
Author(s):  
Karsten Grote ◽  
Harald Schütt ◽  
Bernhard Schieffer
Keyword(s):  
Lupus Erythematosus ◽  
Acute Infection ◽  
Critical Role ◽  
Cell Types ◽  
Immune Defense ◽  
Toll Like Receptors ◽  
Inflammatory Disorders ◽  
Repair Mechanisms ◽  
New Treatment ◽  
Molecular Patterns

Toll-like receptors (TLRs) are known as pattern-recognition receptors related to the Toll protein ofDrosophila. After recognition of pathogen-associated molecular patterns of microbial origin, the TLRs alert the immune system, and initiate innate and adaptive immune responses. The TLR system, though, is not confined solely to the leukocyte-mediated immune defense against exogenous pathogens. Besides myeloid cells, TLR expression has been reported in multiple tissues and cell types, including epithelial and endothelial cells. Moreover, despite the microbial patterns that are commonly accepted as TLR ligands, there is increasing evidence that TLRs also recognize host-derived molecules. In this regard, recent studies point to an involvement of TLRs in various chronic inflammatory disorders and cardiovascular diseases, including atherosclerosis, rheumatoid arthritis, systemic lupus erythematosus, and even cancer. A common feature of these disorders is an enhanced so-called inflammation-induced angiogenesis. However, inflammation-induced angiogenesis is not solely a key component of pathogen defense during acute infection or chronic inflammatory disorders, but also plays a critical role in repair mechanisms, e.g., wound healing and subsequent tissue regeneration. Interestingly, the latest research could coincidentally demonstrate that TLR activation promotes angiogenesis in various inflammatory settings in response to both exogenous and endogenous ligands, although the precise mode of action of TLRs in this context still remains ambiguous. The objective of this review is to present evidence for the implication of TLRs in angiogenesis during physiological and pathophysiological processes, and the potential clinical relevance for new treatment regimes involving TLR modulation.

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