scholarly journals The Small GTPase Arf6: An Overview of Its Mechanisms of Action and of Its Role in Host–Pathogen Interactions and Innate Immunity

2019 ◽  
Vol 20 (9) ◽  
pp. 2209 ◽  
Author(s):  
Tim Van Acker ◽  
Jan Tavernier ◽  
Frank Peelman

The small GTase Arf6 has several important functions in intracellular vesicular trafficking and regulates the recycling of different types of cargo internalized via clathrin-dependent or -independent endocytosis. It activates the lipid modifying enzymes PIP 5-kinase and phospholipase D, promotes actin polymerization, and affects several functionally distinct processes in the cell. Arf6 is used for the phagocytosis of pathogens and can be directly or indirectly targeted by various pathogens to block phagocytosis or induce the uptake of intracellular pathogens. Arf6 is also used in the signaling of Toll-like receptors and in the activation of NADPH oxidases. In this review, we first give an overview of the different roles and mechanisms of action of Arf6 and then focus on its role in innate immunity and host–pathogen interactions.

Author(s):  
Johannes Westman ◽  
Sergio Grinstein

The ability of phagosomes to halt microbial growth is intimately linked to their ability to acidify their luminal pH. Establishment and maintenance of an acidic lumen requires precise co-ordination of H+ pumping and counter-ion permeation to offset the countervailing H+ leakage. Despite the best efforts of professional phagocytes, however, a number of specialized pathogens survive and even replicate inside phagosomes. In such instances, pathogens target the pH-regulatory machinery of the host cell in an effort to survive inside or escape from phagosomes. This review aims to describe how phagosomal pH is regulated during phagocytosis, why it varies in different types of professional phagocytes and the strategies developed by prototypical intracellular pathogens to manipulate phagosomal pH to survive, replicate, and eventually escape from the phagocyte.


2020 ◽  
Vol 88 (7) ◽  
Author(s):  
Emily E. Rosowski

ABSTRACT Macrophages are a key cell type in innate immunity. Years of in vitro cell culture studies have unraveled myriad macrophage pathways that combat pathogens and demonstrated how pathogen effectors subvert these mechanisms. However, in vitro cell culture studies may not accurately reflect how macrophages fit into the context of an innate immune response in whole animals with multiple cell types and tissues. Larval zebrafish have emerged as an intermediate model of innate immunity and host-pathogen interactions to bridge the gap between cell culture studies and mammalian models. These organisms possess an innate immune system largely conserved with that of humans and allow state-of-the-art genetic and imaging techniques, all in the context of an intact organism. Using larval zebrafish, researchers are elucidating the function of macrophages in response to many different infections, including both bacterial and fungal pathogens. The goal of this review is to highlight studies in zebrafish that utilized live-imaging techniques to analyze macrophage activities in response to pathogens. Recent studies have explored the roles of specific pathways and mechanisms in macrophage killing ability, explored how pathogens subvert these responses, identified subsets of macrophages with differential microbicidal activities, and implicated macrophages as an intracellular niche for pathogen survival and trafficking. Research using this model continues to advance our understanding of how macrophages, and specific pathways inside these cells, fit into complex multicellular innate immune responses in vivo, providing important information on how pathogens evade these pathways and how we can exploit them for development of treatments against microbial infections.


2021 ◽  
Vol 134 (5) ◽  
pp. jcs258537

ABSTRACTFirst Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Thibault Rosazza is first author on ‘Dynamic imaging reveals surface exposure of virulent Leishmania amastigotes during pyroptosis of infected macrophages’, published in JCS. Thibault conducted the research described in this article while a master's student in Dr Gerald Spaeth's lab at Institut Pasteur, Unite de Parasitologie Moleculaire et Signalisation, and is now a rotation PhD student in the lab of Dr Gabriel Solberger at University of Dundee, investigating host–pathogen interactions, emphasizing innate immunity modulations.


2020 ◽  
Vol 20 (6) ◽  
pp. 444-465 ◽  
Author(s):  
Jessica Ceramella ◽  
Domenico Iacopetta ◽  
Alexia Barbarossa ◽  
Anna Caruso ◽  
Fedora Grande ◽  
...  

Protein Kinases (PKs) are a heterogeneous family of enzymes that modulate several biological pathways, including cell division, cytoskeletal rearrangement, differentiation and apoptosis. In particular, due to their crucial role during human tumorigenesis and cancer progression, PKs are ideal targets for the design and development of effective and low toxic chemotherapeutics and represent the second group of drug targets after G-protein-coupled receptors. Nowadays, several compounds have been claimed to be PKs inhibitors, and some of them, such as imatinib, erlotinib and gefitinib, have already been approved for clinical use, whereas more than 30 others are in various phases of clinical trials. Among them, some natural or synthetic carbazole-based molecules represent promising PKs inhibitors due to their capability to interfere with PK activity by different mechanisms of action including the ability to act as DNA intercalating agents, interfere with the activity of enzymes involved in DNA duplication, such as topoisomerases and telomerases, and inhibit other proteins such as cyclindependent kinases or antagonize estrogen receptors. Thus, carbazoles can be considered a promising this class of compounds to be adopted in targeted therapy of different types of cancer.


2018 ◽  
Vol 18 (10) ◽  
pp. 957-966 ◽  
Author(s):  
Milene Aparecida Andrade ◽  
Mariana Aparecida Braga ◽  
Pedro Henrique Souza Cesar ◽  
Marcus Vinicius Cardoso Trento ◽  
Mariana Araújo Espósito ◽  
...  

Background: Essential oils are complex mixtures of low molecular weight compounds extracted from plants. Their main constituents are terpenes and phenylpropanoids, which are responsible for their biological and pharmaceutical properties, such as insecticidal, parasiticidal, antimicrobial, antioxidant, anti-inflammatory, analgesic, antinociceptive, anticarcinogenic, and antitumor properties. Cancer is a complex genetic disease considered as a serious public health problem worldwide, accounting for more than 8 million deaths annually. Objective: The activities of prevention and treatment of different types of cancer and the medicinal potential of essential oils are addressed in this review. Conclusion: Several studies have demonstrated anti-carcinogenic and antitumor activity for many essential oils obtained from various plant species. They may be used as a substitution to or in addition to conventional anti-cancer therapy. Although many studies report possible mechanisms of action for essential oils compounds, more studies are necessary in order to apply them safely and appropriately in cancer therapy.


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