scholarly journals Microtubule plus-end dynamics link wound repair to the innate immune response

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Clara Taffoni ◽  
Shizue Omi ◽  
Caroline Huber ◽  
Sébastien Mailfert ◽  
Mathieu Fallet ◽  
...  

The skin protects animals from infection and physical damage. In Caenorhabditis elegans, wounding the epidermis triggers an immune reaction and a repair response, but it is not clear how these are coordinated. Previous work implicated the microtubule cytoskeleton in the maintenance of epidermal integrity (Chuang et al., 2016). Here, by establishing a simple wounding system, we show that wounding provokes a reorganisation of plasma membrane subdomains. This is followed by recruitment of the microtubule plus end-binding protein EB1/EBP-2 around the wound and actin ring formation, dependent on ARP2/3 branched actin polymerisation. We show that microtubule dynamics are required for the recruitment and closure of the actin ring, and for the trafficking of the key signalling protein SLC6/SNF-12 toward the injury site. Without SNF-12 recruitment, there is an abrogation of the immune response. Our results suggest that microtubule dynamics coordinate the cytoskeletal changes required for wound repair and the concomitant activation of innate immunity.

2019 ◽  
Author(s):  
Clara Taffoni ◽  
Shizue Omi ◽  
Caroline Huber ◽  
Sebastien Mailfert ◽  
Matthieu Fallet ◽  
...  

AbstractAs a first line of defence against the environment, the epidermis protect animals from infection and physical damage. In C. elegans, wounding the epidermal epithelium triggers both an immune reaction and a repair response. Exactly how these are controlled, and the degree to which they are inter-connected remains unclear. To address these questions, we established a simple system for simultaneously inflicting precise laser wounds and imaging at high spatial and temporal resolution. We show that in C. elegans, wounding provokes a rapid sealing of the plasma membrane, involving reorganisation of phosphatidylinositol 4,5- bisphosphate domains. This is followed by a radial recruitment at the wound site of EBP-2/EB1, a protein that binds the plus ends of microtubules. EB1 recruitment is accompanied by a reorganisation of microtubules, required for the subsequent recruitment of actin and wound closure. It is also required for the directed trafficking towards the site of injury of the key signalling protein SNF-12. In the absence of SNF-12 recruitment, there is an abrogation of the immune response. Our results suggest that microtubule dynamics coordinate the cytoskeletal changes required for wound repair and the concomitant activation of the innate immune response.


Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 372 ◽  
Author(s):  
Alexandra Sorvina ◽  
Tetyana Shandala ◽  
Shudong Wang ◽  
David J. Sharkey ◽  
Emma Parkinson-Lawrence ◽  
...  

Innate immunity is critical for host defence against pathogen and environmental challenge and this involves the production and secretion of immune mediators, such as antimicrobial peptides and pro-inflammatory cytokines. However, when dysregulated, innate immunity can contribute to multifactorial diseases, including inflammatory rheumatic disorders, type 2 diabetes, cancer, neurodegenerative and cardiovascular diseases and even septic shock. During an innate immune response, antimicrobial peptides and cytokines are trafficked via Rab11 multivesicular endosomes, and then sorted into Rab11 vesicles for traffic to the plasma membrane and secretion. In this study, a cyclin-dependent kinase inhibitor CDKI-73 was used to determine its effect on the innate immune response, based on previously identified targets for this compound. Our results showed that CDKI-73 inhibited the delivery of Rab11 vesicles to the plasma membrane, resulting in the accumulation of large multivesicular Rab11 endosomes near the cell periphery. In addition to the effect on endosome delivery, CDKI-73 down-regulated the amount of innate immune cargo, including the antimicrobial peptide Drosomycin and pro-inflammatory cytokines interleukin-6 (IL-6) and tumour necrosis factor alpha (TNFα). We concluded that CDKI-73 has the potential to regulate the delivery and secretion of certain innate immune cargo, which could be used to control inflammation.


2020 ◽  
pp. 2001584
Author(s):  
Jason Girkin ◽  
Su-Ling Loo ◽  
Camille Esneau ◽  
Steven Maltby ◽  
Francesca Mercuri ◽  
...  

Research questionAssessment of whether TLR2 activation boosts the innate immune response to rhinovirus infection, as a treatment strategy for virus-induced respiratory diseases.MethodsWe employed treatment with a novel TLR2 agonist (INNA-X) prior to rhinovirus infection in mice, and INNA-X treatment in differentiated human bronchial epithelial cells derived from asthmatic-donors. We assessed viral load, immune cell recruitment, cytokines, type I and III IFN production, as well as the lung tissue and epithelial cell immune transcriptome.ResultsWe show in vivo, that a single INNA-X treatment induced innate immune priming characterised by low-level IFN-λ, Fas ligand, chemokine expression and airway lymphocyte recruitment. Treatment 7-days before infection significantly reduced lung viral load, increased IFN-β/λ expression and inhibited neutrophilic inflammation. Corticosteroid treatment enhanced the anti-inflammatory effects of INNA-X. Treatment 1-day before infection increased expression of 190 lung tissue immune genes. This tissue gene expression signature was absent with INNA-X treatment 7-days before infection, suggesting an alternate mechanism, potentially via establishment of immune cell-mediated mucosal innate immunity. In vitro, INNA-X treatment induced a priming response defined by upregulated IFN-λ, chemokine and anti-microbial gene expression that preceded an accelerated response to infection enriched for NF-κB-regulated genes and reduced viral loads, even in epithelial cells derived from asthmatic donors with intrinsic delayed anti-viral immune response.ConclusionAirway epithelial cell TLR2 activation induces prolonged innate immune priming, defined by early NF-κB activation, IFN-λ expression and lymphocyte recruitment. This response enhanced anti-viral innate immunity and reduced virus-induced airway inflammation.


Author(s):  
Dalia Cicily Kattiparambil Dixon ◽  
Chameli Ratan ◽  
Bhagyalakshmi Nair ◽  
Sabitha Mangalath ◽  
Rachy Abraham ◽  
...  

: Innate immunity is the first line of defence elicited by the host immune system to fight against invading pathogens such as viruses and bacteria. From this elementary immune response, the more complex antigen-specific adaptive responses are recruited to provide a long-lasting memory against the pathogens. Innate immunity gets activated when the host cell utilizes a diverse set of receptors known as pattern recognition receptors (PRR) to recognize the viruses that have penetrated the host and respond with cellular processes like complement system, phagocytosis, cytokine release and inflammation and destruction of NK cells. Viral RNA or DNA or viral intermediate products are recognized by receptors like toll-like receptors(TLRs), nucleotide oligomerization domain(NOD)-like receptors (NLRs) and retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) thereby, inducing type I interferon response (IFN) and other proinflammatory cytokines in infected cells or other immune cells. But certain viruses can evade the host innate immune response to replicate efficiently, triggering the spread of the viral infection. The present review describes the similarity in the mechanism chosen by viruses from different families -HIV, SARS-CoV2 and Nipah viruses to evade the innate immune response and how efficiently they establish the infection in the host. The review also addresses the stages of developments of various vaccines against these viral diseases and the challenges encountered by the researchers during vaccine development.


2019 ◽  
Vol 12 (07) ◽  
pp. 1950077 ◽  
Author(s):  
Sulanie Perera ◽  
S. S. N. Perera

Dengue is an acute arthropode-borne virus, belonging to the family Flaviviridae. Currently, there are no vaccines or treatments available against dengue. Thus it is important to understand the dynamics of dengue in order to control the infection. In this paper, we study the long-term dynamics of the model that is presented in [S. D. Perera and S. S. N. Perera, Simulation model for dynamics of dengue with innate and humoral immune responses, Comput. Math. Methods Med. 2018 (2018) 8798057, 18 pp. https://doi.org/10.1155/2018/8798057 ] which describes the interaction of virus with infected and uninfected cells in the presence of innate and humoral immune responses. It was found the model has three equilibria, namely: infection free equilibrium, no immune equilibrium and endemic equilibrium, then analyzed its stability analytically. The analytical findings of each model have been exemplified by numerical simulations. Given the fact that intensity of dengue virus replication at early times of infection could determine clinical outcomes, it is important to understand the impact of innate immunity, which is believed to be the first line of defense against an invading pathogen. For this we carry out a simulation case study to investigate the importance of innate immune response on dengue virus dynamics. A comparison was done assuming that innate immunity was active; innate immunity was in quasi-steady state and innate immunity was inactive during the virus replication process. By a further analysis of the qualitative behavior of the quasi-steady state, it was observed that innate immune response plays a pivotal role in dengue virus dynamics. It can change the dynamical behavior of the system and is essential for the virus clearance.


2020 ◽  
Vol 21 (22) ◽  
pp. 8748
Author(s):  
Stephen Kirchner ◽  
Vivian Lei ◽  
Amanda S. MacLeod

The skin represents the first line of defense and innate immune protection against pathogens. Skin normally provides a physical barrier to prevent infection by pathogens; however, wounds, microinjuries, and minor barrier impediments can present open avenues for invasion through the skin. Accordingly, wound repair and protection from invading pathogens are essential processes in successful skin barrier regeneration. To repair and protect wounds, skin promotes the development of a specific and complex immunological microenvironment within and surrounding the disrupted tissue. This immune microenvironment includes both innate and adaptive processes, including immune cell recruitment to the wound and secretion of extracellular factors that can act directly to promote wound closure and wound antimicrobial defense. Recent work has shown that this immune microenvironment also varies according to the specific context of the wound: the microbiome, neuroimmune signaling, environmental effects, and age play roles in altering the innate immune response to wounding. This review will focus on the role of these factors in shaping the cutaneous microenvironment and how this ultimately impacts the immune response to wounding.


2019 ◽  
Vol 20 (13) ◽  
pp. 3357
Author(s):  
Yang Xu ◽  
Huan Zhao ◽  
Yang Tian ◽  
Kaixia Ren ◽  
Nan Zheng ◽  
...  

Protein kinase C-δ (PKC-δ) is an important protein in the immune system of higher vertebrates. Lampreys, as the most primitive vertebrates, have a uniquevariable lymphocyte receptor (VLR) immune system. PKC-δ-like is a crucial functional gene in lampreys and is highly expressed in their immune organs. In this study, lampreys were stimulated with different immunogens, and lipopolysaccharide (LPS) was found to increase the expression of PKC-δ-like. Overexpression of PKC-δ-like could also effectively activate the innate immune response. We further demonstrated that PKC-δ-like-CF, a catalytic fragment of PKC-δ-like, is responsible for activating the innate immune response, and Thr-211, which is Thr-419 of PKC-δ-like, was confirmed to be the key site affecting PKC-δ-like-CF activity. These results indicated that PKC-δ-like from lamprey may have an important role in the innate immune response.


Vaccines ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 313
Author(s):  
Daniel Sepulveda-Crespo ◽  
Salvador Resino ◽  
Isidoro Martinez

Despite successful treatments, hepatitis C virus (HCV) infections continue to be a significant world health problem. High treatment costs, the high number of undiagnosed individuals, and the difficulty to access to treatment, particularly in marginalized susceptible populations, make it improbable to achieve the global control of the virus in the absence of an effective preventive vaccine. Current vaccine development is mostly focused on weakly immunogenic subunits, such as surface glycoproteins or non-structural proteins, in the case of HCV. Adjuvants are critical components of vaccine formulations that increase immunogenic performance. As we learn more information about how adjuvants work, it is becoming clear that proper stimulation of innate immunity is crucial to achieving a successful immunization. Several hepatic cell types participate in the early innate immune response and the subsequent inflammation and activation of the adaptive response, principally hepatocytes, and antigen-presenting cells (Kupffer cells, and dendritic cells). Innate pattern recognition receptors on these cells, mainly toll-like receptors, are targets for new promising adjuvants. Moreover, complex adjuvants that stimulate different components of the innate immunity are showing encouraging results and are being incorporated in current vaccines. Recent studies on HCV-vaccine adjuvants have shown that the induction of a strong T- and B-cell immune response might be enhanced by choosing the right adjuvant.


2008 ◽  
Vol 295 (2) ◽  
pp. C313-C323 ◽  
Author(s):  
Angelia Lockett ◽  
Mark G. Goebl ◽  
Maureen A. Harrington

The transcription factor NF-κB is an essential regulator of the innate immune response that functions as the first line of defense against infections. Activation of the innate immune response by bacterial lipopolysaccharide (LPS) triggers production of tumor necrosis factor-α (TNF-α) followed by interleukin-1 (IL-1). The IL-1 receptor associated kinase-1 (IRAK-1) is an integral component of the LPS, TNF-α, and IL-1 signaling pathways that regulate NF-κB. Thus we hypothesized that IRAK-1 coordinates cellular NF-κB responses to LPS, TNF-α, and IL-1. In contrast to TNF-α where IRAK-1 subcellular localization does not change, treatment with LPS or IL-1 leads to a loss in cytoplasmic IRAK-1 with a coordinate increase in plasma membrane associated modified IRAK-1. In fibroblasts lacking the type 1 TNF-α receptor (TNF R1), IRAK-1 turnover is altered and modification of IRAK-1 in the plasma membrane is decreased in response to LPS and IL-1, respectively. When NF-κB controlled gene expression is measured, fibroblasts lacking TNF R1 are hyperresponsive to LPS, whereas a more variable response to IL-1 is seen. Further analysis of the LPS response revealed that plasma membrane-associated IRAK-1 is found in Toll 4, IL-1, and TNF R1-containing complexes. The data presented herein suggest a model whereby the TNF R1-IRAK-1 interaction integrates the cellular response to LPS, TNF-α, and IL-1, culminating in a cell poised to activate TNF-α-dependent NF-κB controlled gene expression. In the absence of TNF R1-dependent events, exposure to LPS or IL-1 leads to hyperactivation of the inflammatory response.


2011 ◽  
Vol 300 (2) ◽  
pp. C287-C294 ◽  
Author(s):  
Kimberly K. Long ◽  
Grace K. Pavlath ◽  
Monty Montano

Efficient muscle regeneration requires the clearance of dead and dying tissue via phagocytosis before remodeling. We have previously shown that mice lacking stem cell antigen-1 (Sca-1) display a defect in skeletal muscle regeneration characterized by increased fibrosis and decreased turnover of the extracellular matrix. In the present study we demonstrate that Sca-1−/− mice have a defect in their capacity to recruit soluble IgM, and subsequently C3 complement, to damaged muscle. We hypothesize that this defect in recruitment delays or decreases phagocytosis by macrophages, contributing to the previously observed fibrotic phenotype of these mice. As the primary source of soluble IgM is peritoneal B-1a cells, which are a subset of self-renewing B cells, we analyzed this cell population and observed a significant reduction in B-1a cells in Sca-1−/− animals. Interestingly, these mice are protected from ischemia-reperfusion injury, an acute inflammatory reaction also mediated by IgM and C3 complement that has been linked to a deficit in B-1a cells in previous studies. Collectively, these data reveal a novel role for Sca-1 in innate immunity during muscle regeneration and indicate that further elucidation of immuno-myogenic processes will help to better understand and promote muscle regeneration.


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