scholarly journals Phagocytosis: A Fundamental Process in Immunity

2017 ◽  
Vol 2017 ◽  
pp. 1-18 ◽  
Author(s):  
Carlos Rosales ◽  
Eileen Uribe-Querol
Keyword(s):  
Immune Responses ◽  
Host Response ◽  
Current Knowledge ◽  
General View ◽  
Cellular Mechanisms ◽  
Complex Process ◽  
Fundamental Process ◽  
Target Particle ◽  
Acquired Immune Responses

One hundred years have passed since the death of Élie Metchnikoff (1845–1916). He was the first to observe the uptake of particles by cells and realized the importance of this process for the host response to injury and infection. He also was a strong advocate of the role of phagocytosis in cellular immunity, and with this he gave us the basis for our modern understanding of inflammation and the innate and acquired immune responses. Phagocytosis is an elegant but complex process for the ingestion and elimination of pathogens, but it is also important for the elimination of apoptotic cells and hence fundamental for tissue homeostasis. Phagocytosis can be divided into four main steps: (i) recognition of the target particle, (ii) signaling to activate the internalization machinery, (iii) phagosome formation, and (iv) phagolysosome maturation. In recent years, the use of new tools of molecular biology and microscopy has provided new insights into the cellular mechanisms of phagocytosis. In this review, we present a general view of our current knowledge on phagocytosis. We emphasize novel molecular findings, particularly on phagosome formation and maturation, and discuss aspects that remain incompletely understood.

scholarly journals Rho-mDia1 pathway is required for adhesion, migration, and T-cell stimulation in dendritic cells

Blood ◽  
2010 ◽  
Vol 116 (26) ◽  
pp. 5875-5884 ◽  
Author(s):  
Hideaki Tanizaki ◽  
Gyohei Egawa ◽  
Kayo Inaba ◽  
Tetsuya Honda ◽  
Saeko Nakajima ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Dendritic Cells ◽  
T Cell ◽  
Immune Responses ◽  
Lymph Nodes ◽  
Actin Polymerization ◽  
Cell Stimulation ◽  
T Cell Stimulation ◽  
Acquired Immune Responses

Abstract Dendritic cells (DCs) are essential for the initiation of acquired immune responses through antigen acquisition, migration, maturation, and T-cell stimulation. One of the critical mechanisms in this response is the process actin nucleation and polymerization, which is mediated by several groups of proteins, including mammalian Diaphanous-related formins (mDia). However, the role of mDia in DCs remains unknown. Herein, we examined the role of mDia1 (one of the isoforms of mDia) in DCs. Although the proliferation and maturation of bone marrow-derived DCs were comparable between control C57BL/6 and mDia1-deficient (mDia1−/−) mice, adhesion and spreading to cellular matrix were impaired in mDia1−/− bone marrow–derived DCs. In addition, fluorescein isothiocyanate-induced cutaneous DC migration to draining lymph nodes in vivo and invasive migration and directional migration to CCL21 in vitro were suppressed in mDia1−/− DCs. Moreover, sustained T-cell interaction and T-cell stimulation in lymph nodes were impaired by mDia1 deficiency. Consistent with this, the DC-dependent delayed hypersensitivity response was attenuated by mDia1-deficient DCs. These results suggest that actin polymerization, which is mediated by mDia1, is essential for several aspects of DC-initiated acquired immune responses.

scholarly journals The complex functions of microRNA-150 in allergy, autoimmunity and immune tolerance

2021 ◽  
Vol 5 (4) ◽  
pp. 195-221
Author(s):  
Katarzyna Nazimek ◽  
Keyword(s):  
Immune Responses ◽  
Immune Tolerance ◽  
Therapeutic Potential ◽  
Current Knowledge ◽  
Signaling Cascades ◽  
Cell Functions ◽  
Regulatory Circuits ◽  
Complex Functions ◽  
Genetic Level

<abstract> <p>At present, special efforts are being made to develop the strategies allowing for activation of long-lasting antigen-specific immune tolerance in therapy of allergic and autoimmune diseases. Some of these therapeutic approaches are aimed at modulating cell functions at genetic level by using miRNA-based and miRNA-targeting treatments. Simultaneously, the crucial role of extracellular vesicles as natural miRNA conveyors is highlighted for induction of antigen-specific immune tolerance, especially that they appear to be easily manipulatable for therapeutic applications. Among other immune-related miRNAs, miR-150 is getting special attention as it is differently expressed by immune cells at various stages of their maturation and differentiation. In addition, miR-150 is involved in different signaling cascades orchestrating humoral and cell-mediated mechanisms of both innate and adaptive immune responses. Therefore, miR-150 is considered a master regulator of immunity in mammals. Currently, physiological miR-150-dependent regulatory circuits and causes of their malfunctioning that underlie the pathogenesis of allergic and autoimmune disorders are being unraveled. Thus, present review summarizes the current knowledge of the role of miR-150 in the pathogenesis and complications of these diseases. Furthermore, the involvement of miR-150 in regulation of immune responses to allergens and self-antigens and in induction of antigen-specific immune tolerance is discussed with the special emphasis on the therapeutic potential of this miRNA.</p> </abstract>

scholarly journals Regulatory Immune Cells in Idiopathic Pulmonary Fibrosis: Friends or Foes?

2021 ◽  
Vol 12 ◽  
Author(s):  
Chiel van Geffen ◽  
Astrid Deißler ◽  
Markus Quante ◽  
Harald Renz ◽  
Dominik Hartl ◽  
...  
Keyword(s):  
Immune System ◽  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Immune Responses ◽  
Immune Cells ◽  
Current Knowledge ◽  
Suppressor Cells ◽  
Interstitial Lung Diseases ◽  
Stromal Stem Cells

The immune system is receiving increasing attention for interstitial lung diseases, as knowledge on its role in fibrosis development and response to therapies is expanding. Uncontrolled immune responses and unbalanced injury-inflammation-repair processes drive the initiation and progression of idiopathic pulmonary fibrosis. The regulatory immune system plays important roles in controlling pathogenic immune responses, regulating inflammation and modulating the transition of inflammation to fibrosis. This review aims to summarize and critically discuss the current knowledge on the potential role of regulatory immune cells, including mesenchymal stromal/stem cells, regulatory T cells, regulatory B cells, macrophages, dendritic cells and myeloid-derived suppressor cells in idiopathic pulmonary fibrosis. Furthermore, we review the emerging role of regulatory immune cells in anti-fibrotic therapy and lung transplantation. A comprehensive understanding of immune regulation could pave the way towards new therapeutic or preventive approaches in idiopathic pulmonary fibrosis.

scholarly journals Pleiotropic Role of Notch Signaling in Human Skin Diseases

2020 ◽  
Vol 21 (12) ◽  
pp. 4214 ◽  
Author(s):  
Rossella Gratton ◽  
Paola Maura Tricarico ◽  
Chiara Moltrasio ◽  
Ana Sofia Lima Estevão de Oliveira ◽  
Lucas Brandão ◽  
...  
Keyword(s):  
Notch Signaling ◽  
Human Skin ◽  
Hidradenitis Suppurativa ◽  
Target Genes ◽  
Skin Diseases ◽  
Current Knowledge ◽  
Cellular Mechanisms ◽  
Degos Disease ◽  
Cellular Pathways

Notch signaling orchestrates the regulation of cell proliferation, differentiation, migration and apoptosis of epidermal cells by strictly interacting with other cellular pathways. Any disruption of Notch signaling, either due to direct mutations or to an aberrant regulation of genes involved in the signaling route, might lead to both hyper- or hypo-activation of Notch signaling molecules and of target genes, ultimately inducing the onset of skin diseases. The mechanisms through which Notch contributes to the pathogenesis of skin diseases are multiple and still not fully understood. So far, Notch signaling alterations have been reported for five human skin diseases, suggesting the involvement of Notch in their pathogenesis: Hidradenitis Suppurativa, Dowling Degos Disease, Adams–Oliver Syndrome, Psoriasis and Atopic Dermatitis. In this review, we aim at describing the role of Notch signaling in the skin, particularly focusing on the principal consequences associated with its alterations in these five human skin diseases, in order to reorganize the current knowledge and to identify potential cellular mechanisms in common between these pathologies.

3 MECHANSISMS OF INTESTINAL FUNGI RECOGNITION AND CONTROL

2020 ◽  
Vol 26 (Supplement_1) ◽  
pp. S41-S41
Author(s):  
Irina Leonardi ◽  
Iliyan Iliev
Keyword(s):  
Steady State ◽  
Immune Responses ◽  
Antigen Presentation ◽  
Intestinal Inflammation ◽  
Mononuclear Phagocytes ◽  
Fungal Communities ◽  
Cellular Mechanisms ◽  
Anti Fungal ◽  
And Control

Abstract Background and Objectives Intestinal fungal communities are perturbed in several autoimmune diseases and have been shown to influence disease outcome. We have shown that intestinal resident CX3CR1+ mononuclear phagocytes (MNPs) can sense gut fungi and are crucial for the initiation of immune responses both locally and at distant sites. These results suggest that recognition of fungi by gut phagocytes might be involved in the pathogenesis of immune-related diseases such as IBD. Despite the identification of a few molecules involved in the recognition and immunity to intestinal fungi the cellular mechanisms governing the initiation and regulation of the mucosal immune responses to the mycobiota remain unknown. We sought to identify the functional role of distinct phagocytic subsets in the response to fungal communities in the gut during health and intestinal disease. Methods We used Candida albicans, the main opportunistic fungus found in IBD patients, as model fungal colonizer, with a focus on the mechanisms mediating the adaptive response. To elucidate the mechanisms and consequences of the recognition of fungi by phagocytic subsets in the lamina propria we used genetic models of depletion and deletion of specific subtypes of phagocytes. We further targeted fungal recognition and antigen presentation in phagocytes to investigate the mechanisms leading to the induction of adaptive anti-fungal responses. Results C. albicans colonization induced a consistent increase in Th17 cells in the intestinal mucosa that was decreased upon depletion of CX3CR1+ MNPs. Genetic depletion of CX3CR1+ MNPs in mice led to changes in gut fungal communities and to severe chemically induced intestinal inflammation that was rescued by antifungal treatment. Recognition of fungi through a C-type lectin/Syk pathways and antigen presentation via MHC-II were necessary for the induction of adaptive T cell in responses to C. albicans colonization. Conclusion Our work aims at defining the role of CX3CR1+ MNPs and cDCs in the initiation of anti-fungal immune responses in the intestine at the steady state. We have demonstrated the essential role of CX3CR1+ MNPs in the initiation of antifungal responses in the intestine at steady state and for the control of fungi at steady state and during inflammation. We have demonstrated the importance of CX3CR1+ MNPs in the control of the intestinal mycobiota.

scholarly journals Role of Hedgehog Signaling in Vasculature Development, Differentiation, and Maintenance

2019 ◽  
Vol 20 (12) ◽  
pp. 3076 ◽  
Author(s):  
Candice Chapouly ◽  
Sarah Guimbal ◽  
Pierre-Louis Hollier ◽  
Marie-Ange Renault
Keyword(s):  
Hedgehog Signaling ◽  
Current Knowledge ◽  
Vascular Biology ◽  
Cerebrovascular Diseases ◽  
Future Research ◽  
Cellular Mechanisms ◽  
Vascular Integrity ◽  
Hh Signaling ◽  
Vessel Integrity

The role of Hedgehog (Hh) signaling in vascular biology has first been highlighted in embryos by Pepicelli et al. in 1998 and Rowitch et al. in 1999. Since then, the proangiogenic role of the Hh ligands has been confirmed in adults, especially under pathologic conditions. More recently, the Hh signaling has been proposed to improve vascular integrity especially at the blood–brain barrier (BBB). However, molecular and cellular mechanisms underlying the role of the Hh signaling in vascular biology remain poorly understood and conflicting results have been reported. As a matter of fact, in several settings, it is currently not clear whether Hh ligands promote vessel integrity and quiescence or destabilize vessels to promote angiogenesis. The present review relates the current knowledge regarding the role of the Hh signaling in vasculature development, maturation and maintenance, discusses the underlying proposed mechanisms and highlights controversial data which may serve as a guideline for future research. Most importantly, fully understanding such mechanisms is critical for the development of safe and efficient therapies to target the Hh signaling in both cancer and cardiovascular/cerebrovascular diseases.

Dietary and Physiological Effects of Zinc on the Immune System

2021 ◽  
Vol 41 (1) ◽  
Author(s):  
Inga Wessels ◽  
Henrike Josephine Fischer ◽  
Lothar Rink
Keyword(s):  
Immune Responses ◽  
Immune Cells ◽  
Immune Cell ◽  
Current Knowledge ◽  
Annual Review ◽  
Publication Date ◽  
Biological Processes ◽  
And Function ◽  
Broad Overview

Evidence for the importance of zinc for all immune cells and for mounting an efficient and balanced immune response to various environmental stressors has been accumulating in recent years. This article describes the role of zinc in fundamental biological processes and summarizes our current knowledge of zinc's effect on hematopoiesis, including differentiation into immune cell subtypes. In addition, the important role of zinc during activation and function of immune cells is detailed and associated with the specific immune responses to bacteria, parasites, and viruses. The association of zinc with autoimmune reactions and cancers as diseases with increased or decreased immune responses is also discussed. This article provides a broad overview of the manifold roles that zinc, or its deficiency, plays in physiology and during various diseases. Consequently, we discuss why zinc supplementation should be considered, especially for people at risk of deficiency. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Molecular Crosstalking among Noncoding RNAs: A New Network Layer of Genome Regulation in Cancer

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Marco Ragusa ◽  
Cristina Barbagallo ◽  
Duilia Brex ◽  
Angela Caponnetto ◽  
Matilde Cirnigliaro ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Structural Integrity ◽  
Current Knowledge ◽  
Noncoding Rnas ◽  
Special Focus ◽  
Cellular Mechanisms ◽  
Protein Coding ◽  
The Past ◽  
Higher Eukaryotes

Over the past few years, noncoding RNAs (ncRNAs) have been extensively studied because of the significant biological roles that they play in regulation of cellular mechanisms. ncRNAs are associated to higher eukaryotes complexity; accordingly, their dysfunction results in pathological phenotypes, including cancer. To date, most research efforts have been mainly focused on how ncRNAs could modulate the expression of protein-coding genes in pathological phenotypes. However, recent evidence has shown the existence of an unexpected interplay among ncRNAs that strongly influences cancer development and progression. ncRNAs can interact with and regulate each other through various molecular mechanisms generating a complex network including different species of RNAs (e.g., mRNAs, miRNAs, lncRNAs, and circRNAs). Such a hidden network of RNA-RNA competitive interactions pervades and modulates the physiological functioning of canonical protein-coding pathways involved in proliferation, differentiation, and metastasis in cancer. Moreover, the pivotal role of ncRNAs as keystones of network structural integrity makes them very attractive and promising targets for innovative RNA-based therapeutics. In this review we will discuss: (1) the current knowledge on complex crosstalk among ncRNAs, with a special focus on cancer; and (2) the main issues and criticisms concerning ncRNAs targeting in therapeutics.

Parasite glycans and antibody-mediated immune responses inSchistosomainfection

Parasitology ◽  
2012 ◽  
Vol 139 (9) ◽  
pp. 1219-1230 ◽  
Author(s):  
ANGELA VAN DIEPEN ◽  
NIELS S. J. VAN DER VELDEN ◽  
CORNELIS H. SMIT ◽  
MONIEK H. J. MEEVISSEN ◽  
CORNELIS H. HOKKE
Keyword(s):  
Immune Responses ◽  
Current Knowledge ◽  
Expression Profiles ◽  
Antibody Responses ◽  
Infection Rates ◽  
Immune Intervention ◽  
Protective Mechanisms ◽  
Future Directions ◽  
Slow Development

SUMMARYSchistosome infections in humans are characterized by the development of chronic disease and high re-infection rates after treatment due to the slow development of immunity. It appears that anti-schistosome antibodies are at least partially mediating protective mechanisms. Efforts to develop a vaccine based on immunization with surface-exposed or secreted larval or worm proteins are ongoing. Schistosomes also express a large number of glycans as part of their glycoprotein and glycolipid repertoire, and antibody responses to those glycans are mounted by the infected host. This observation raises the question if glycans might also form novel vaccine targets for immune intervention in schistosomiasis. This review summarizes current knowledge of antibody responses and immunity in experimental and natural infections withSchistosoma, the expression profiles of schistosome glycans (the glycome), and antibody responses to individual antigenic glycan motifs. Future directions to study anti-glycan responses in schistosomiasis in more detail in order to address more precisely the possible role of glycans in antibody-mediated immunity are discussed.

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