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Phylogeny of the mucosal immune system
Published in Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald, Principles of Mucosal Immunology, 2020
Robert D. Miller, Irene Salinas
In D. melanogaster, antimicrobial peptide and Duox-dependent reactive oxygen species production are key innate immune mechanisms in the gut. The gut microbiota of mosquitoes regulates antimicrobial peptide and C-type lectin expression via the immune deficiency (Imd) pathway. Mosquito C-type lectins regulate antimicrobial peptide expression, coat bacterial surfaces, and contribute to the maintenance of the gut microbiota in a similar manner to vertebrate mucosal immunoglobulins.
Novel studies on Drosophila melanogaster model reveal the roles of JNK-Jak/STAT axis and intestinal microbiota in insulin resistance
Published in Journal of Drug Targeting, 2023
Qinghao Meng, Yidong Xu, Ying Li, Yiwen Wang
The release of ROS (reactive oxygen species) functions as a double-edged sword: on one hand, it helps fight against infection in physiological concentration, and on the other hand, promotes the inflammatory response and damages tissues when it is dysregulated [64–66]. However, a high-sugar diet induces an imbalance between the energy ingested and the energy expended, thus impairing mitochondrial function and causing the accumulation of ROS [67,68]. In humans, high-blood sugar interacts with vascular endothelial cells and directly induces the vascular inflammatory response by activating JNK phosphorylation, and ROS is required for the activation of JNK during inflammatory response [69,70]. Maria M. Bayliak et al. [71] also proved in their study that a high-calorie diet induces the release of ROS and oxidative stress, which leads to insulin resistance in D. melanogaster. In D. melanogaster, when the gram-negative bacteria stimulates the IMD pathway, it not only enhances the activity of the JNK pathway and promotes the release of ROS, but also promotes the activation of JNK pathway by increasing the level of cell death [72,73].
How relevant are in vitro culture models for study of tick-pathogen interactions?
Published in Pathogens and Global Health, 2021
Cristiano Salata, Sara Moutailler, Houssam Attoui, Erich Zweygarth, Lygia Decker, Lesley Bell-Sakyi
An interesting study compared the ability to phagocytose and destroy live B. burgdorferi s.s. spirochetes of vector (IDE12 and ISE6) and non-vector (DAE15) tick cell lines [162]. IDE12 and DAE15 cells were highly phagocytic, with over 80% of cells containing spirochetes after 24 h, while with ISE6 cells the spirochetes remained extracellular and appeared viable. DAE15 cells phagocytosed spirochetes faster and in higher numbers than IDE12 cells. The ability of the non-vector D. andersoni DAE15 cells to rapidly ingest and destroy B. burgdorferi in vitro [162] reflects the reported ability of non-vector Dermacentor variabilis ticks to destroy inoculated spirochetes using both cellular and humoral responses [163]. More recently, siRNA-mediated RNAi transcript knockdown in ISE6 cells and in I. scapularis and D. andersoni ticks was used to examine the role of components of the tick IMD pathway in infection with B. burgdorferi s.s., A. phagocytophilum and A. marginale [133]. Good agreement was obtained between the in vitro ISE6 model and live, intact ticks inoculated with siRNAs for several IMD pathway genes identified as having positive or negative effects on replication of all three pathogens.
The use of Drosophila melanogaster as a model organism to study immune-nanotoxicity
Published in Nanotoxicology, 2019
Cheng Teng Ng, Liya E Yu, Choon Nam Ong, Boon Huat Bay, Gyeong Hun Baeg
Interestingly, Drosophila also evokes humoral response, which is an inducible anti-bacterial immune response that leads to the secretion of AMPs into the hemolymph (Boman et al., 1972). AMP sequences are highly conserved from insects to mammals, and their expression is governed by the conserved NF-κB/PARP1–dependent pathway (Bahar and Ren, 2013; Ji et al., 2016). AMPs are primarily synthesized by the fat body for systemic circulation; although the barrier epithelial cells are also capable of synthesizing AMPs. For local infection, tissue-specific AMPs are produced by organs such as the trachea (functions as a respiratory organ), Malpighian tubules and gut. There are two classical signaling pathways that regulate inducible immune responses in the event of bacteria or fungi infection in Drosophila, namely the Toll pathway and the immune deficiency (Imd) pathway (Becker et al., 2010; Hoffmann and Reichhart, 2002).