scholarly journals Pioneer neutrophils release chromatin within in vivo swarms

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Hannah M Isles ◽  
Catherine A Loynes ◽  
Sultan Alasmari ◽  
Fu Chuen Kon ◽  
Katherine M Henry ◽  
...  
Keyword(s):  
Tissue Injury ◽  
Damage Model ◽  
Neutrophil Migration ◽  
Initial Step ◽  
Transgenic Zebrafish ◽  
In Vivo Models ◽  
Essential Components ◽  
Cellular Components

Neutrophils are rapidly recruited to inflammatory sites where their coordinated migration forms clusters, a process termed neutrophil swarming. The factors that modulate early stages of neutrophil swarming are not fully understood, requiring the development of new in vivo models. Using transgenic zebrafish larvae to study endogenous neutrophil migration in a tissue damage model, we demonstrate that neutrophil swarming is a conserved process in zebrafish immunity, sharing essential features with mammalian systems. We show that neutrophil swarms initially develop around an individual pioneer neutrophil. We observed the violent release of extracellular cytoplasmic and nuclear fragments by the pioneer and early swarming neutrophils. By combining in vitro and in vivo approaches to study essential components of neutrophil extracellular traps (NETs), we provide in-depth characterisation and high-resolution imaging of the composition and morphology of these release events. Using a photoconversion approach to track neutrophils within developing swarms, we identify that the fate of swarm-initiating pioneer neutrophils involves extracellular chromatin release and that the key NET components gasdermin, neutrophil elastase, and myeloperoxidase are required for the swarming process. Together our findings demonstrate that release of cellular components by pioneer neutrophils is an initial step in neutrophil swarming at sites of tissue injury.

scholarly journals Recombinant human activated protein C inhibits integrin-mediated neutrophil migration

Blood ◽  
2009 ◽  
Vol 113 (17) ◽  
pp. 4078-4085 ◽  
Author(s):  
Gwendolyn F. Elphick ◽  
Pranita P. Sarangi ◽  
Young-Min Hyun ◽  
Joseph A. Hollenbaugh ◽  
Alfred Ayala ◽  
...  
Keyword(s):  
Protein C ◽  
Tissue Injury ◽  
Neutrophil Migration ◽  
Activated Protein C ◽  
Beneficial Effects ◽  
Rgd Sequence ◽  
Leukocyte Integrins ◽  
Pathologic Processes

Abstract Integrin-mediated cell migration is central to many biologic and pathologic processes. During inflammation, tissue injury results from excessive infiltration and sequestration of activated leukocytes. Recombinant human activated protein C (rhAPC) has been shown to protect patients with severe sepsis, although the mechanism underlying this protective effect remains unclear. Here, we show that rhAPC directly binds to β1 and β3 integrins and inhibits neutrophil migration, both in vitro and in vivo. We found that human APC possesses an Arg-Gly-Asp (RGD) sequence, which is critical for the inhibition. Mutation of this sequence abolished both integrin binding and inhibition of neutrophil migration. In addition, treatment of septic mice with a RGD peptide recapitulated the beneficial effects of rhAPC on survival. Thus, we conclude that leukocyte integrins are novel cellular receptors for rhAPC and the interaction decreases neutrophil recruitment into tissues, providing a potential mechanism by which rhAPC may protect against sepsis.

scholarly journals In vitro and in vivo models for peritonitis demonstrate unchanged neutrophil migration after exposure to dialysis fluids

2004 ◽  
Vol 19 (4) ◽  
pp. 831-839 ◽  
Author(s):  
A. G. A. Welten ◽  
M. Zareie ◽  
J. van den Born ◽  
P. M. ter Wee ◽  
C. G. Schalkwijk ◽  
...  
Keyword(s):  
Neutrophil Migration ◽  
In Vivo Models ◽  
Dialysis Fluids

scholarly journals Role of endothelial microRNA 155 on capillary leakage in systemic inflammation

Critical Care ◽  
2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Valerie Etzrodt ◽  
Temitayo O. Idowu ◽  
Heiko Schenk ◽  
Benjamin Seeliger ◽  
Antje Prasse ◽  
...  
Keyword(s):  
Vascular Leakage ◽  
Transgenic Zebrafish ◽  
Wildtype Mouse ◽  
Dependent Manner ◽  
Capillary Leakage ◽  
In Vivo Models ◽  
Junction Protein

Abstract Background Capillary leakage is a key contributor to the pathological host response to infections. The underlying mechanisms remain incompletely understood, and the role of microRNAs (MIR) has not been investigated in detail. We hypothesized that specific MIRs might be regulated directly in the endothelium thereby contributing to vascular leakage. Methods SmallRNA sequencing of endotoxemic murine pulmonary endothelial cells (ECs) was done to detect regulated vascular MIRs. In vivo models: transgenic zebrafish (flk1:mCherry/l-fabp:eGFP-DPB), knockout/wildtype mouse (B6.Cg-Mir155tm1.1Rsky/J); disease models: LPS 17.5 mg/kgBW and cecal ligation and puncture (CLP); in vitro models: stimulated human umbilical vein EC (HUVECs), transendothelial electrical resistance. Results Endothelial MIR155 was identified as a promising candidate in endotoxemic murine pulmonary ECs (25 × upregulation). Experimental overexpression in a transgenic zebrafish line and in HUVECs was sufficient to induce spontaneous vascular leakage. To the contrary, genetic MIR155 reduction protects against permeability both in vitro and in endotoxemia in vivo in MIR155 heterozygote knockout mice thereby improving survival by 40%. A tight junction protein, Claudin-1, was down-regulated both in endotoxemia and by experimental MIR155 overexpression. Translationally, MIR155 was detectable at high levels in bronchoalveolar fluid of patients with ARDS compared to healthy human subjects. Conclusions We found that MIR155 is upregulated in the endothelium in mouse and men as part of a systemic inflammatory response and might contribute to the pathophysiology of vascular leakage in a Claudin-1-dependent manner. Future studies have to clarify whether MIR155 could be a potential therapeutic target.

scholarly journals Endogenous pioneer neutrophils release NETs during the swarming response in zebrafish

2019 ◽  
Author(s):  
Hannah M. Isles ◽  
Catherine A. Loynes ◽  
Noémie Hamilton ◽  
Clare F. Muir ◽  
Anastasia Kadochnikova ◽  
...  
Keyword(s):  
Tissue Damage ◽  
Damage Model ◽  
Neutrophil Migration ◽  
Transgenic Zebrafish ◽  
Histone H2a ◽  
Zebrafish Model ◽  
Extracellular Traps ◽  
Sequence Of Events ◽  
Phase Sequence

AbstractNeutrophils are rapidly recruited to inflammatory sites where they coordinate their migration to form clusters, a process termed neutrophil swarming. The factors which modulate neutrophil swarming during its early stages are not fully understood, requiring the development of new in vivo models. Using transgenic zebrafish larvae to study endogenous neutrophil migration in a tissue damage model, we demonstrate that neutrophil swarming is a conserved process in zebrafish immunity, sharing essential features with mammalian systems. We show that neutrophil swarms initially develop around a pioneer neutrophil, in a three-phase sequence of events. By adopting a high-resolution confocal microscopy approach, we observed the release of cell fragments by early swarming neutrophils. We developed a neutrophil specific histone H2A transgenic reporter line TgBAC(mpx:GFP)i114;Tg(lyz:H2A-mCherry)sh530 to study neutrophil extracellular traps (NETs), and found that endogenous neutrophils recruited to sites of tissue damage released NETs at the start of the swarming process. The optical transparency achieved using the zebrafish model has provided some of the highest resolution imaging of NET release in vivo to date. Using a combination of transgenic reporter lines and DNA intercalating agents, we demonstrate that pioneer neutrophils release extracellular traps during the swarming response, suggesting that cell death signalling via NETosis might be important in driving the swarming response.

scholarly journals Zebrafish Models of Cancer Therapy-Induced Cardiovascular Toxicity

2021 ◽  
Vol 8 (2) ◽  
pp. 8
Author(s):  
Sarah Lane ◽  
Luis Alberto More ◽  
Aarti Asnani
Keyword(s):  
Cancer Therapy ◽  
High Throughput ◽  
Early Developmental Stage ◽  
Transgenic Zebrafish ◽  
Cardiovascular Toxicity ◽  
Zebrafish Model ◽  
In Vivo Models ◽  
Mechanisms Of Toxicity

Purpose of review: Both traditional and novel cancer therapies can cause cardiovascular toxicity in patients. In vivo models integrating both cardiovascular and cancer phenotypes allow for the study of on- and off-target mechanisms of toxicity arising from these agents. The zebrafish is the optimal whole organism model to screen for cardiotoxicity in a high throughput manner, while simultaneously assessing the role of cardiotoxicity pathways on the cancer therapy’s antitumor effect. Here we highlight established zebrafish models of human cardiovascular disease and cancer, the unique advantages of zebrafish to study mechanisms of cancer therapy-associated cardiovascular toxicity, and finally, important limitations to consider when using the zebrafish to study toxicity. Recent findings: Cancer therapy-associated cardiovascular toxicities range from cardiomyopathy with traditional agents to arrhythmias and thrombotic complications associated with newer targeted therapies. The zebrafish can be used to identify novel therapeutic strategies that selectively protect the heart from cancer therapy without affecting antitumor activity. Advances in genome editing technology have enabled the creation of several transgenic zebrafish lines valuable to the study of cardiovascular and cancer pathophysiology. Summary: The high degree of genetic conservation between zebrafish and humans, as well as the ability to recapitulate cardiotoxic phenotypes observed in patients with cancer, make the zebrafish an effective model to study cancer therapy-associated cardiovascular toxicity. Though this model provides several key benefits over existing in vitro and in vivo models, limitations of the zebrafish model include the early developmental stage required for most high-throughput applications.

scholarly journals pICln Inhibits snRNP Biogenesis by Binding Core Spliceosomal Proteins

1999 ◽  
Vol 19 (6) ◽  
pp. 4113-4120 ◽  
Author(s):  
William T. Pu ◽  
Grigory B. Krapivinsky ◽  
Luba Krapivinsky ◽  
David E. Clapham
Keyword(s):  
Motor Neurons ◽  
Initial Step ◽  
Sm Proteins ◽  
Core Proteins ◽  
Essential Components ◽  
Binding Core ◽  
Smn Protein ◽  
Sm Protein

ABSTRACT The U1, U2, U4, U5, and U6 small nuclear ribonucleoproteins (snRNPs) form essential components of spliceosomes, the machinery that removes introns from pre-mRNAs in eukaryotic cells. A critical initial step in the complex process of snRNP biogenesis is the assembly of a group of common core proteins (Sm proteins) on spliceosomal snRNA. In this study we show by multiple independent methods that the protein pICln associates with Sm proteins in vivo and in vitro. The binding of pICln to Sm proteins interferes with Sm protein assembly on spliceosomal snRNAs and inhibits import of snRNAs into the nucleus. Furthermore, pICln prevents the interaction of Sm proteins with the survival of motor neurons (SMN) protein, an interaction that has been shown to be critical for snRNP biogenesis. These findings lead us to propose a model in which pICln participates in the regulation of snRNP biogenesis, at least in part by interfering with Sm protein interaction with SMN protein.

scholarly journals Adherence ofHelicobacter pylorito the Gastric Mucosa

1997 ◽  
Vol 11 (3) ◽  
pp. 243-248 ◽  
Author(s):  
Marguerite Clyne ◽  
Brendan Drumm
Keyword(s):  
Helicobacter Pylori ◽  
Gastric Mucosa ◽  
Bacterial Adhesion ◽  
Initial Step ◽  
Gastric Epithelium ◽  
In Vivo Models ◽  
Enteric Diseases ◽  
H Pylori

Bacterial adhesion to the intestinal epithelium is a critical initial step in the pathogenesis of many enteric diseases.Helicobacter pyloriis a duodenal pathogen that adheres to the gastric epithelium and causes gastritis and peptic ulceration. The mechanism by whichH pyloricauses disease has not yet been elucidated but adherence to the gastric mucosa is thought to be an important virulence determinant of the organism. What is known about adherence ofH pylorito the gastric mucosa is summarized. Topics discussed are the mechanism ofH pyloriadherence; in vitro and in vivo models ofH pyloriinfection; and adherence and potential adhesins and receptors forH pylori.

Melatonin modifies tumor hypoxia and metabolism by inhibiting HIF-1α and energy metabolic pathway in the in vitro and in vivo models of breast cancer

2019 ◽  
Vol 2 (4) ◽  
pp. 83-98 ◽  
Author(s):  
André De Lima Mota ◽  
Bruna Vitorasso Jardim-Perassi ◽  
Tialfi Bergamin De Castro ◽  
Jucimara Colombo ◽  
Nathália Martins Sonehara ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Glucose Metabolism ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Carbonic Anhydrases ◽  
In Vivo Models ◽  
Ca Ix ◽  
Gene And Protein Expression

Breast cancer is the most common cancer among women and has a high mortality rate. Adverse conditions in the tumor microenvironment, such as hypoxia and acidosis, may exert selective pressure on the tumor, selecting subpopulations of tumor cells with advantages for survival in this environment. In this context, therapeutic agents that can modify these conditions, and consequently the intratumoral heterogeneity need to be explored. Melatonin, in addition to its physiological effects, exhibits important anti-tumor actions which may associate with modification of hypoxia and Warburg effect. In this study, we have evaluated the action of melatonin on tumor growth and tumor metabolism by different markers of hypoxia and glucose metabolism (HIF-1α, glucose transporters GLUT1 and GLUT3 and carbonic anhydrases CA-IX and CA-XII) in triple negative breast cancer model. In an in vitro study, gene and protein expressions of these markers were evaluated by quantitative real-time PCR and immunocytochemistry, respectively. The effects of melatonin were also tested in a MDA-MB-231 xenograft animal model. Results showed that melatonin treatment reduced the viability of MDA-MB-231 cells and tumor growth in Balb/c nude mice (p <0.05). The treatment significantly decreased HIF-1α gene and protein expression concomitantly with the expression of GLUT1, GLUT3, CA-IX and CA-XII (p <0.05). These results strongly suggest that melatonin down-regulates HIF-1α expression and regulates glucose metabolism in breast tumor cells, therefore, controlling hypoxia and tumor progression. 

Current Challenges in the Development of Vaccines and Drugs Against Emerging Vector-borne Diseases

2019 ◽  
Vol 26 (16) ◽  
pp. 2974-2986 ◽  
Author(s):  
Kwang-sun Kim
Keyword(s):  
New Host ◽  
In Vivo Models ◽  
Vector Borne Diseases ◽  
Novel Drugs ◽  
Huge Impact ◽  
Tick Borne Disease ◽  
Vector Borne ◽  
Living Organisms

Vectors are living organisms that transmit infectious diseases from an infected animal to humans or another animal. Biological vectors such as mosquitoes, ticks, and sand flies carry pathogens that multiply within their bodies prior to delivery to a new host. The increased prevalence of Vector-Borne Diseases (VBDs) such as Aedes-borne dengue, Chikungunya (CHIKV), Zika (ZIKV), malaria, Tick-Borne Disease (TBD), and scrub typhus has a huge impact on the health of both humans and livestock worldwide. In particular, zoonotic diseases transmitted by mosquitoes and ticks place a considerable burden on public health. Vaccines, drugs, and vector control methods have been developed to prevent and treat VBDs and have prevented millions of deaths. However, development of such strategies is falling behind the rapid emergence of VBDs. Therefore, a comprehensive approach to fighting VBDs must be considered immediately. In this review, I focus on the challenges posed by emerging outbreaks of VBDs and discuss available drugs and vaccines designed to overcome this burden. Research into promising drugs needs to be upgraded and fast-tracked, and novel drugs or vaccines being tested in in vitro and in vivo models need to be moved into human clinical trials. Active preventive tactics, as well as new and upgraded diagnostics, surveillance, treatments, and vaccination strategies, need to be monitored constantly if we are to manage VBDs of medical importance.

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