scholarly journals Atg5-Deficient Mice Infected with Francisella tularensis LVS Demonstrate Increased Survival and Less Severe Pathology in Internal Organs

2020 ◽  
Vol 8 (10) ◽  
pp. 1531
Author(s):  
Ina Kelava ◽  
Mirna Mihelčić ◽  
Mateja Ožanič ◽  
Valentina Marečić ◽  
Maša Knežević ◽  
...  
Keyword(s):  
Francisella Tularensis ◽  
Cell Types ◽  
Internal Organs ◽  
Tularensis Subsp ◽  
Cell Cytosol ◽  
Severe Pathology ◽  
Deficient Mice

Francisella tularensis is a highly virulent intracellular pathogen that proliferates within various cell types and can infect a multitude of animal species. Francisella escapes the phagosome rapidly after infection and reaches the host cell cytosol where bacteria undergo extensive replication. Once cytosolic, Francisella becomes a target of an autophagy-mediated process. The mechanisms by which autophagy plays a role in replication of this cytosolic pathogen have not been fully elucidated. In vitro, F. tularensis avoids degradation via autophagy and the autophagy process provides nutrients that support its intracellular replication, but the role of autophagy in vivo is unknown. Here, we investigated the role of autophagy in the pathogenesis of tularemia by using transgenic mice deficient in Atg5 in the myeloid lineage. The infection of Atg5-deficient mice with Francisella tularensis subsp. holarctica live vaccine strain (LVS) resulted in increased survival, significantly reduced bacterial burden in the mouse organs, and less severe histopathological changes in the spleen, liver and lung tissues. The data highlight the contribution of Atg5 in the pathogenesis of tularemia in vivo.

Abstract 376: Downregulation of Endogenous Apelinergic Axis Mediates Endothelial and Organismal Senescence

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Rahul Rai ◽  
Asish K Ghosh ◽  
Layton H Smith ◽  
Douglas E Vaughan
Keyword(s):  
Endothelial Cells ◽  
Replicative Senescence ◽  
Cell Types ◽  
Ang Ii ◽  
Systematic Assessment ◽  
Multiple Cell ◽  
Deficient Mice

Background: Apelinergic signaling is a recently discovered GPCR mediated pathway. Endothelial cells are the main source of endogenous apelin (apln) while apelin receptor (aplnr) is present on multiple cell types. Since the role of endogenous apelinergic pathway within the context of senescence is largely unknown, we ask if levels of apln- aplnr vary with aging. We also investigate the effects of downregulated apln- aplnr on cellular and organismal aging. Approach and Results: To assess variations in endogenous apln- aplnr with aging, we compared their levels in 1 month (young) and 1 year old (old) WT mice. We noticed significant downregulation of apln- aplnr with chronological senescence in multiple tissues. Expression of apelin was also reduced with replicative senescence of endothelial cells. L-NAME administration, a model of stress induced senescence, also repressed aortic and cardiac apln. To address the mechanism involved in downregulation of apln- aplnr, we administered young wild type mice with Ang II. After a week of Ang II, there was significant downregulation of aortic apln and aplnr. Ang II and TGF-β also repressed apln and aplnr in vitro . Next we investigated the effects of downregulated apln on endothelial cells. In response to shRNA mediated apelin knockdown, cells exhibited slower proliferation and upregulated senescence associated markers. We observed similar results when endothelial aplnr was blocked with an antagonist, ML221. In addition, apln and aplnr deficient mice also exhibited features of cardiovascular aging, including ventricular hypertrophy and lower EF. Importantly, aplnr deficient mice at eight months of age were also hypertensive. Conclusion: We provide a systematic assessment of senescence associated variation in levels of apln- aplnr. We demonstrate the role of Ang II- TGF-β axis in downregulating apln- aplnr during chronological and stress induced senescence in vivo and in vitro . We propose a novel model of Ang II- TGF-β induced senescence. Where in, with aging Ang II and TGF-β repress endogenous apln- aplnr. Downregulation of endogenous apln- aplnr axis decreases beneficial “youthful” effects of apelin, resulting in endothelial dysfunction and accelerated organismal aging.

The use of siRNA as a pharmacological tool to assess a role for the transcription factor NF-IL6 in the brain under in vitro and in vivo conditions during LPS-induced inflammatory stimulation

2017 ◽  
Vol 28 (6) ◽  
Author(s):  
Jelena Damm ◽  
Joachim Roth ◽  
Rüdiger Gerstberger ◽  
Christoph Rummel
Keyword(s):  
Transcription Factor ◽  
Brain Cells ◽  
Nuclear Factor ◽  
Si Rna ◽  
The Brain ◽  
Deficient Mice ◽  
Transcription Factor Nuclear Factor

AbstractBackground:Studies with NF-IL6-deficient mice indicate that this transcription factor plays a dual role during systemic inflammation with pro- and anti-inflammatory capacities. Here, we aimed to characterize the role of NF-IL6 specifically within the brain.Methods:In this study, we tested the capacity of short interfering (si) RNA to silence the inflammatory transcription factor nuclear factor-interleukin 6 (NF-IL6) in brain cells underResults:In cells of a mixed neuronal and glial primary culture from the ratConclusions:This approach was, thus, not suitable to characterize the role NF-IL6 in the brain

scholarly journals Toll-Like Receptor 2 Controls the Gamma Interferon Response to Francisella tularensis by Mouse Liver Lymphocytes

2007 ◽  
Vol 75 (11) ◽  
pp. 5338-5345 ◽  
Author(s):  
Kee-Jong Hong ◽  
Jason R. Wickstrum ◽  
Hung-Wen Yeh ◽  
Michael J. Parmely
Keyword(s):  
Francisella Tularensis ◽  
Cell Types ◽  
Gamma Interferon ◽  
Interferon Response ◽  
Interleukin 12 ◽  
Toll Like Receptor ◽  
Wild Type ◽  
Ifn Γ ◽  
Deficient Mice

ABSTRACT The production of gamma interferon (IFN-γ) is a key step in the protective innate immune response to Francisella tularensis. Natural killer cells and T cells in the liver are important sources of this cytokine during primary F. tularensis infections, and interleukin-12 (IL-12) appears to be an essential coactivating cytokine for hepatic IFN-γ expression. The present study was undertaken to determine whether or not macrophages (Mφ) or dendritic cells (DC) provide coactivating signals for the liver IFN-γ response in vitro, whether IL-12 mediates these effects, and whether Toll-like receptor (TLR) signaling is essential to induce this costimulatory activity. Both bone marrow-derived Mφ and DC significantly augmented the IFN-γ response of F. tularensis-challenged liver lymphocytes in vitro. While both cell types produced IL-12p40 in response to F. tularensis challenge, only DC secreted large quantities of IL-12p70. DC from both IL-12p35-deficient and TLR2-deficient mice failed to produce IL-12p70 and did not costimulate liver lymphocytes for IFN-γ production in response to viable F. tularensis organisms. Conversely, liver lymphocytes from TLR2-deficient mice cocultured with wild-type accessory cells produced IFN-γ at levels comparable to those for wild-type hepatic lymphocytes. These findings indicate that TLR2 controls hepatic lymphocyte IFN-γ responses to F. tularensis by regulating DC IL-12 production. While Mφ also coinduced hepatic IFN-γ production in response to F. tularensis, they did so in a fashion less dependent on TLR2.

scholarly journals The critical immunosuppressive effect of MDSC-derived exosomes in the tumor microenvironment

2020 ◽  
Author(s):  
Mohammad H. Rashid ◽  
Thaiz F. Borin ◽  
Roxan Ara ◽  
Raziye Piranlioglu ◽  
Bhagelu R. Achyut ◽  
...  
Keyword(s):  
T Cells ◽  
Tumor Microenvironment ◽  
Tumor Growth ◽  
Cd8 T Cells ◽  
Suppressor Cells ◽  
Cell Types ◽  
Biological Macromolecules

AbstractMyeloid-derived suppressor cells (MDSCs) are an indispensable component of the tumor microenvironment (TME), and our perception regarding the role of MDSCs in tumor promotion is attaining extra layer of intricacy in every study. In conjunction with MDSC’s immunosuppressive and anti-tumor immunity, they candidly facilitate tumor growth, differentiation, and metastasis in several ways that yet to be explored. Alike any other cell types, MDSCs also release a tremendous amount of exosomes or nanovesicles of endosomal origin and partake in intercellular communications by dispatching biological macromolecules. There has not been any experimental study done to characterize the role of MDSCs derived exosomes (MDSC exo) in the modulation of TME. In this study, we isolated MDSC exo and demonstrated that they carry a significant amount of proteins that play an indispensable role in tumor growth, invasion, angiogenesis, and immunomodulation. We observed higher yield and more substantial immunosuppressive potential of exosomes isolated from MDSCs in the primary tumor area than those are in the spleen or bone marrow. Our in vitro data suggest that MDSC exo are capable of hyper activating or exhausting CD8 T-cells and induce reactive oxygen species production that elicits activation-induced cell death. We confirmed the depletion of CD8 T-cells in vivo by treating the mice with MDSC exo. We also observed a reduction in pro-inflammatory M1-macrophages in the spleen of those animals. Our results indicate that immunosuppressive and tumor-promoting functions of MDSC are also implemented by MDSC-derived exosomes which would open up a new avenue of MDSC research and MDSC-targeted therapy.

scholarly journals Revisiting the role of IRF3 in inflammation and immunity by conditional and specifically targeted gene ablation in mice

2018 ◽  
Vol 115 (20) ◽  
pp. 5253-5258 ◽  
Author(s):  
Hideyuki Yanai ◽  
Shiho Chiba ◽  
Sho Hangai ◽  
Kohei Kometani ◽  
Asuka Inoue ◽  
...  
Keyword(s):  
Immune Cell ◽  
Cell Types ◽  
Type I ◽  
Type I Ifn ◽  
Cell Type ◽  
Gene Ablation ◽  
Cell Type Specific

IFN regulatory factor 3 (IRF3) is a transcription regulator of cellular responses in many cell types that is known to be essential for innate immunity. To confirm IRF3’s broad role in immunity and to more fully discern its role in various cellular subsets, we engineered Irf3-floxed mice to allow for the cell type-specific ablation of Irf3. Analysis of these mice confirmed the general requirement of IRF3 for the evocation of type I IFN responses in vitro and in vivo. Furthermore, immune cell ontogeny and frequencies of immune cell types were unaffected when Irf3 was selectively inactivated in either T cells or B cells in the mice. Interestingly, in a model of lipopolysaccharide-induced septic shock, selective Irf3 deficiency in myeloid cells led to reduced levels of type I IFN in the sera and increased survival of these mice, indicating the myeloid-specific, pathogenic role of the Toll-like receptor 4–IRF3 type I IFN axis in this model of sepsis. Thus, Irf3-floxed mice can serve as useful tool for further exploring the cell type-specific functions of this transcription factor.

scholarly journals Intranasal Borna Disease Virus (BoDV-1) Infection: Insights into Initial Steps and Potential Contagiosity

2019 ◽  
Vol 20 (6) ◽  
pp. 1318 ◽  
Author(s):  
Alexandra Kupke ◽  
Sabrina Becker ◽  
Konstantin Wewetzer ◽  
Barbara Ahlemeyer ◽  
Markus Eickmann ◽  
...  
Keyword(s):  
Viral Infections ◽  
Cell Types ◽  
Nerve Fibers ◽  
Olfactory Pathway ◽  
Adult Rats ◽  
The Central Nervous System ◽  
Receptor Neurons

Mammalian Bornavirus (BoDV-1) typically causes a fatal neurologic disorder in horses and sheep, and was recently shown to cause fatal encephalitis in humans with and without transplant reception. It has been suggested that BoDV-1 enters the central nervous system (CNS) via the olfactory pathway. However, (I) susceptible cell types that replicate the virus for successful spread, and (II) the role of olfactory ensheathing cells (OECs), remained unclear. To address this, we studied the intranasal infection of adult rats with BoDV-1 in vivo and in vitro, using olfactory mucosal (OM) cell cultures and the cultures of purified OECs. Strikingly, in vitro and in vivo, viral antigen and mRNA were present from four days post infection (dpi) onwards in the olfactory receptor neurons (ORNs), but also in all other cell types of the OM, and constantly in the OECs. In contrast, in vivo, BoDV-1 genomic RNA was only detectable in adult and juvenile ORNs, nerve fibers, and in OECs from 7 dpi on. In vitro, the rate of infection of OECs was significantly higher than that of the OM cells, pointing to a crucial role of OECs for infection via the olfactory pathway. Thus, this study provides important insights into the transmission of neurotropic viral infections with a zoonotic potential.

scholarly journals Interleukin 6 is essential for in vivo development of B lineage neoplasms.

1995 ◽  
Vol 182 (1) ◽  
pp. 243-248 ◽  
Author(s):  
D M Hilbert ◽  
M Kopf ◽  
B A Mock ◽  
G Köhler ◽  
S Rudikoff
Keyword(s):  
Plasma Cell ◽  
Plasma Cells ◽  
Tumor Development ◽  
Selective Pressures ◽  
B Lineage ◽  
Deficient Mice ◽  
Human B Cell

Interleukin (IL) 6 has been suggested to be the major cytokine responsible for proliferation of neoplastic plasma cells in both human myeloma and mouse plasmacytoma. Much of the evidence supporting this suggestion is derived from in vitro studies in which the survival or proliferation of some plasma cell tumors has been found to be IL-6 dependent. However, it remains unclear whether this dependency is the consequence of in vivo or in vitro selective pressures that preferentially expand IL-6-responsive tumor cells, or whether it reflects a critical in vivo role for IL-6 in plasma cell neoplasia. To address this question, we have attempted to induce plasma cell tumors in normal mice and in IL-6-deficient mice generated by introduction of a germline-encoded null mutation in the IL-6 gene. The results demonstrate that mice homozygous (+/+) or heterozygous (+/-) for the wild-type IL-6 allele yield the expected incidences of plasma cell tumors. In contrast, mice homozygous for the IL-6-null allele (-/-) are completely resistant to plasma cell tumor development. These studies define the essential role of IL-6 in the development of B lineage tumors in vivo and provide experimental support for continued efforts to modulate this cytokine in the treatment of appropriate human B cell malignancies.

scholarly journals A comprehensive protein–protein interactome for yeast PAS kinase 1 reveals direct inhibition of respiration through the phosphorylation of Cbf1

2014 ◽  
Vol 25 (14) ◽  
pp. 2199-2215 ◽  
Author(s):  
Desiree DeMille ◽  
Benjamin T. Bikman ◽  
Andrew D. Mathis ◽  
John T. Prince ◽  
Jordan T. Mackay ◽  
...  
Keyword(s):  
Glucose Homeostasis ◽  
Protein Modification ◽  
Molecular Mechanisms ◽  
Binding Partners ◽  
Pas Kinase ◽  
Protein Interactome ◽  
Deficient Mice

Per-Arnt-Sim (PAS) kinase is a sensory protein kinase required for glucose homeostasis in yeast, mice, and humans, yet little is known about the molecular mechanisms of its function. Using both yeast two-hybrid and copurification approaches, we identified the protein–protein interactome for yeast PAS kinase 1 (Psk1), revealing 93 novel putative protein binding partners. Several of the Psk1 binding partners expand the role of PAS kinase in glucose homeostasis, including new pathways involved in mitochondrial metabolism. In addition, the interactome suggests novel roles for PAS kinase in cell growth (gene/protein expression, replication/cell division, and protein modification and degradation), vacuole function, and stress tolerance. In vitro kinase studies using a subset of 25 of these binding partners identified Mot3, Zds1, Utr1, and Cbf1 as substrates. Further evidence is provided for the in vivo phosphorylation of Cbf1 at T211/T212 and for the subsequent inhibition of respiration. This respiratory role of PAS kinase is consistent with the reported hypermetabolism of PAS kinase–deficient mice, identifying a possible molecular mechanism and solidifying the evolutionary importance of PAS kinase in the regulation of glucose homeostasis.

Role of inducible nitric oxide synthase in the regulation of leucocyte recruitment

2000 ◽  
Vol 100 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Michael J. HICKEY
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Nitric Oxide Synthase ◽  
Cell Types ◽  
Adhesive Interactions ◽  
Oxide Synthase ◽  
Leucocyte Recruitment

Constitutively produced nitric oxide released by endothelial cells has been shown to act as an endogenous agent which inhibits the rolling and adhesion of leucocytes in the microcirculation. However, during various types of inflammation, expression of the inducible form of nitric oxide synthase (iNOS) can dramatically increase the amount of nitric oxide present in tissues. Furthermore, as iNOS can be expressed by a wide variety of cell types, the distribution of nitric oxide is likely to be altered relative to that in unstimulated tissue. Under these conditions, it is less well understood whether iNOS-derived nitric oxide retains the anti-adhesive capabilities of constitutively produced nitric oxide. This review summarizes work done to examine this issue. Three main approaches have been used. In vitro studies have examined the role of iNOS in adhesive interactions between stimulated endothelial cells and leucocytes, providing evidence of an anti-adhesive effect of iNOS. In addition, the role of iNOS has been examined in vivo in animal models of inflammation using pharmacological iNOS inhibitors. These experiments were extended by the advent of the iNOS-deficient (iNOS-/-) mouse. Intravital microscopy studies of these mice have indicated that, under conditions of low-dose endotoxaemia, iNOS-derived nitric oxide can inhibit leucocyte rolling and adhesion. The potential mechanisms for these effects are discussed. In contrast, several other studies have observed either no effect or an enhancing effect of iNOS on inflammatory leucocyte recruitment. Taken together, these studies suggest that the importance of iNOS in modulating leucocyte recruitment can vary according to the type of inflammatory response.

scholarly journals The Role of PPAR Gamma in Systemic Sclerosis

PPAR Research ◽  
2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Andréa Tavares Dantas ◽  
Michelly Cristiny Pereira ◽  
Moacyr Jesus Barreto de Melo Rego ◽  
Laurindo Ferreira da Rocha ◽  
Ivan da Rocha Pitta ◽  
...  
Keyword(s):  
Systemic Sclerosis ◽  
Lung Fibrosis ◽  
Ppar Gamma ◽  
Immune Dysregulation ◽  
Unknown Etiology ◽  
Internal Organs ◽  
Medical Need

Fibrosis is recognized as an important feature of many chronic diseases, such as systemic sclerosis (SSc), an autoimmune disease of unknown etiology, characterized by immune dysregulation and vascular injury, followed by progressive fibrosis affecting the skin and multiple internal organs. SSc has a poor prognosis because no therapy has been shown to reverse or arrest the progression of fibrosis, representing a major unmet medical need. Recently, antifibrotic effects of PPARγligands have been studiedin vitroandin vivoand some theories have emerged leading to new insights. Aberrant PPARγfunction seems to be implicated in pathological fibrosis in the skin and lungs. This antifibrotic effect is mainly related to the inhibition of TGF-β/Smad signal transduction but other pathways can be involved. This review focused on recent studies that identified PPARγas an important novel pathway with critical roles in regulating connective tissue homeostasis, with emphasis on skin and lung fibrosis and its role on systemic sclerosis.

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