scholarly journals Profiles and Dynamics of the Transcriptome of Microglial Cells Reveal their Inflammatory Status

2021 ◽  
Author(s):  
Keren Zohar ◽  
Elyad Lezmi ◽  
Fanny Reichert ◽  
Tsiona Eliyahu ◽  
Shlomo Rotshenker ◽  
...  
Keyword(s):  
Cell System ◽  
Aging Brain ◽  
Primary Role ◽  
Transient Wave ◽  
Inflammatory Status ◽  
Activated State ◽  
Transcriptional Changes ◽  
Brain Homeostasis

The primary role of microglia in the maintenance of brain homeostasis is to respond to disturbances in the microenvironment. In this study, we cultured murine neonatal microglia and activated them with lipopolysaccharide (LPS) and benzoyl ATP (bzATP) to characterize changes in the transcriptome in response to various in vivo stimuli caused by pathogens, injury, or toxins. Activation by bzATP, an agonist of purinergic receptors, induces a transient wave of transcriptional changes. However, a long-lasting transcriptional profile affecting thousands of genes occurs only following a combination of bzATP and LPS. This profile is dominated by a coordinated induction of cytokines (e.g., IL1-alpha; and IL1-beta), chemokines, and their direct regulators. Many of these inflammatory-related genes are up-regulated by several orders of magnitude. We identified the TNF-alpha and NF-kB pathways as the principal hubs for signaling of interleukin and chemokine induction in this cell system. We propose that primary microglia under controlled activation paradigms can be used for testing reagents that could attenuate their activated state. Such a microglial system could serve as a model for changes occurring in the aging brain and neurodegenerative diseases.

scholarly journals Retromer subunit, VPS29, regulates synaptic transmission and is required for endolysosomal function in the aging brain

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Hui Ye ◽  
Shamsideen A Ojelade ◽  
David Li-Kroeger ◽  
Zhongyuan Zuo ◽  
Liping Wang ◽  
...  
Keyword(s):  
Synaptic Transmission ◽  
Protein Complex ◽  
Adult Brain ◽  
Aging Brain ◽  
Gtpase Activating Protein ◽  
Ultrastructural Evidence ◽  
Aging Adults ◽  
And Function ◽  
Brain Homeostasis

Retromer, including Vps35, Vps26, and Vps29, is a protein complex responsible for recycling proteins within the endolysosomal pathway. Although implicated in both Parkinson’s and Alzheimer’s disease, our understanding of retromer function in the adult brain remains limited, in part because Vps35 and Vps26 are essential for development. In Drosophila, we find that Vps29 is dispensable for embryogenesis but required for retromer function in aging adults, including for synaptic transmission, survival, and locomotion. Unexpectedly, in Vps29 mutants, Vps35 and Vps26 proteins are normally expressed and associated, but retromer is mislocalized from neuropil to soma with the Rab7 GTPase. Further, Vps29 phenotypes are suppressed by reducing Rab7 or overexpressing the GTPase activating protein, TBC1D5. With aging, retromer insufficiency triggers progressive endolysosomal dysfunction, with ultrastructural evidence of impaired substrate clearance and lysosomal stress. Our results reveal the role of Vps29 in retromer localization and function, highlighting requirements for brain homeostasis in aging.

The role of 5-HT7 receptors on isoproterenol-induced myocardial infarction in rats with high-fat diet exacerbated coronary endothelial dysfunction

2020 ◽  
Vol 39 (8) ◽  
pp. 1005-1018 ◽  
Author(s):  
I Cinar ◽  
Z Halici ◽  
B Dincer ◽  
B Sirin ◽  
E Cadirci
Keyword(s):  
Myocardial Infarction ◽  
Endothelial Dysfunction ◽  
High Fat Diet ◽  
Density Lipoprotein ◽  
Heart Tissue ◽  
High Fat ◽  
Inflammatory Status

The presence of 5-HT7r’s in both human and rat cardiovascular and immune tissues and their contribution to inflammatory conditions prompted us to hypothesize that these receptors contribute in acute myocardial infarction (MI) with underlying chronic endothelial dysfunction. We investigated the role of 5-HT7 receptors on heart tissue that damaged by isoproterenol (ISO)-induced MI in rats with high-fat diet (HFD). In vitro and in vivo effects of 5-HT7r agonist (LP44) and antagonist (SB269970) have been investigated on the H9C2 cell line and rats, respectively. For in vivo analyses, rats were fed with HFD for 8 weeks and after this period ISO-induced MI model has been applied to rat. To investigate the role of 5-HT7r’s, two different doses of LP44 and SB269970 were evaluated and compared with standard hypolipidemic agent, atorvastatin. In vitro studies showed that LP44 has protective and proliferative effects on rat cardiomyocytes. Also in in vivo studies stimulating 5-HT7r’s by LP44 improved blood lipid profile (decreased total cholesterol, low-density lipoprotein-C, and triglyceride, increased high-density lipoprotein), decreased cardiac damage markers (creatine kinase and troponin-I), and corrected inflammatory status (tumor necrosis factor-α, interleukin-6). Our results showed significant improvement in LP44 administered rats in terms of histopathologic analyses. In damaged tissues, 5-HT7 mRNA expression increased and agonist administration decreased this elevation significantly. We determined for the first time that 5-HT7r’s are overexpressed in ISO-induced MI of rats with underlying HFD-induced endothelial dysfunction. Restoration of this overexpression by LP44, a 5-HT7r agonist, ameliorated heart tissue in physiopathologic, enzymatic, and molecular level, showing the cardiac role of these receptors and suggesting them as future potential therapeutic targets.

scholarly journals Influenza virus-specific CD4+ T helper type 2 T lymphocytes do not promote recovery from experimental virus infection.

1994 ◽  
Vol 180 (4) ◽  
pp. 1273-1282 ◽  
Author(s):  
M B Graham ◽  
V L Braciale ◽  
T J Braciale
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Lymphocytes ◽  
Cd4 T Cells ◽  
Primary Role ◽  
T Helper ◽  
Helper Type

T lymphocytes play a primary role in recovery from viral infections and in antiviral immunity. Although viral-specific CD8+ and CD4+ T cells have been shown to be able to lyse virally infected targets in vitro and promote recovery from lethal infection in vivo, the role of CD4+ T lymphocytes and their mechanism(s) of action in viral immunity are not well understood. The ability to further dissect the role that CD4+ T cells play in the immune response to a number of pathogens has been greatly enhanced by evidence for more extensive heterogeneity among the CD4+ T lymphocytes. To further examine the role of CD4+ T cells in the immune response to influenza infection, we have generated influenza virus-specific CD4+ T cell clones from influenza-primed BALB/c mice with differential cytokine secretion profiles that are defined as T helper type 1 (Th1) clones by the production of interleukin 2 (IL-2) and interferon gamma (IFN-gamma), or as Th2 clones by the production of IL-4, IL-5, and IL-10. Our studies have revealed that Th1 clones are cytolytic in vitro and protective against lethal challenge with virus in vivo, whereas Th2 clones are noncytolytic and not protective. Upon further evaluation of these clonal populations we have shown that not only are the Th2 clones nonprotective, but that pulmonary pathology is exacerbated as compared with control mice as evidenced by delayed viral clearance and massive pulmonary eosinophilia. These data suggest that virus-specific CD4+ T cells of the Th2 subset may not play a primary role in virus clearance and recovery and may lead to immune mediated potentiation of injury.

Sometimes a cigar is just a cigar

Blood ◽  
2010 ◽  
Vol 116 (9) ◽  
pp. 1394-1395
Author(s):  
Shih-Hon Li ◽  
Daniel A. Lawrence
Keyword(s):  
Plasminogen Activator ◽  
Molecular Interactions ◽  
Mouse Strain ◽  
Mutant Form ◽  
Primary Role ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator

In this issue of Blood, Connolly and colleagues describe an elegant approach to studying the significance of specific molecular interactions in vivo. The authors have “knocked-in” a mutant form of the protease, urokinase-type plasminogen activator (uPA), into the murine uPA locus, to create a mouse strain (PlauGFDhu/GFDhu) where the interaction between endogenous uPA and its receptor (uPAR) is selectively disrupted, while leaving other functions of both uPA and uPAR intact. Their findings suggest that the primary role of uPAR in vivo is to promote fibrinolysis within tissues through localization of uPA, and that many of the previously described activities of uPAR may be secondary to this process.1

Synthesis of Artificial Models of Sickle Red Cells

1987 ◽  
Vol 110 ◽  
Author(s):  
Roderick D. Macgregor ◽  
Noel Taylor ◽  
Bertram Lubin ◽  
C. Anthony Hunt
Keyword(s):  
Lipid Bilayer ◽  
Bilayer Membrane ◽  
Cell System ◽  
Red Cells ◽  
Primary Role ◽  
Red Cell ◽  
Before And After ◽  
Synthetic Cells

AbstractThe primary role of a red cell substitute is to deliver oxygen to cells eitherin vivo or in vitro. It seems reasonable to mimic evolution, which solved the problem of oxygen delivery in many species by encapsulating oxygen carrying proteins in cell-sized delivery systems. We have successfully synthesized and tested an artificial red cell (Neohemocytes: see Science 230, 1165, 1985). How many properties or functions of red cells can one mimic synthetically? Can these synthetic cells serve as useful models? Here we report the first successful synthesis of an artificial model sickle cell. No reproducible, model cell system was previously available for research. A procedure identical to that used to prepare normal neohemocytes (NHC) was employed using sickle hemoglobin (HbS). The starting material was O2or CO liganded HbS at a concentration of approximately 15g% in a 30 mOsm phosphate buffer; this solution was kept ultrahypotonic until the final stage of the process. The lipid bilayer membrane was formed during a prolonged adjustment of the osmolality to 300 mOsm. The final step was removal of unencapsulated HbS. Sickle NHC were examined in parallel with normal (HbA containing) NHC by scanning and thin section electron microscopy before and after deoxygenation. These synthetic cells do sickle! Some look remarkably like red blood cells, only much smaller. Our data suggests that polymerization of the HbS within sickle NHC may be initiated by a different mechanism than the polymerization of purified solutions of HbS. The typical lipid bilayer seen in HbA containing NBC was essentially absent in the sickle NHC: similar results have been reported for irreversibly sickled red cells. Sickle NHC thus have remarkable potential to function as model sickle cells.

scholarly journals Resveratrol Inhibits Oxidative Stress and Prevents Mitochondrial Damage Induced by Zinc Oxide Nanoparticles in Zebrafish (Danio rerio)

2020 ◽  
Vol 21 (11) ◽  
pp. 3838 ◽  
Author(s):  
Roberta Giordo ◽  
Gheyath K. Nasrallah ◽  
Ola Al-Jamal ◽  
Panagiotis Paliogiannis ◽  
Gianfranco Pintus
Keyword(s):  
Oxidative Stress ◽  
Zinc Oxide ◽  
Protective Mechanism ◽  
Primary Role ◽  
Zebrafish Model ◽  
Structural Abnormalities ◽  
Health Related ◽  
Toxic Potential

Despite their wide industrial use, Zinc oxide (ZnO) nanoparticles (NPs) exhibit a high toxic potential while concerns of their health-related risks are still present, urging additional in vivo clarification studies. Oxidative stress is recognized as the primary trigger of NP-associated toxicity, suggesting antioxidants as a promising counteractive approach. Here, we investigated the protective effect of the natural antioxidant resveratrol against ZnO NP-induced toxicity in vivo using the zebrafish model. Our findings demonstrate that resveratrol counteracts ZnO NP-induced zebrafish lethality preventing cardiac morphological and functional damage. NP-induced vascular structural abnormalities during embryonic fish development were significantly counteracted by resveratrol treatment. Mechanistically, we further showed that resveratrol inhibits ROS increase, prevents mitochondrial membrane potential dysfunction, and counteracts cell apoptosis/necrosis elicited by ZnO NP. Overall, our data provide further evidence demonstrating the primary role of oxidative stress in NP-induced damage, and highlight new insights concerning the protective mechanism of antioxidants against nanomaterial toxicity.

scholarly journals Aggregation via the Red, Dry, and Rough Morphotype Is Not a Virulence Adaptation in Salmonella enterica Serovar Typhimurium

2008 ◽  
Vol 76 (3) ◽  
pp. 1048-1058 ◽  
Author(s):  
A. P. White ◽  
D. L. Gibson ◽  
G. A. Grassl ◽  
W. W. Kay ◽  
B. B. Finlay ◽  
...  
Keyword(s):  
In Vivo Imaging ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Primary Role ◽  
Wild Type ◽  
Serovar Typhimurium ◽  
Cell Densities ◽  
Two Populations

ABSTRACT The Salmonella rdar (red, dry, and rough) morphotype is an aggregative and resistant physiology that has been linked to survival in nutrient-limited environments. Growth of Salmonella enterica serovar Typhimurium was analyzed in a variety of nutrient-limiting conditions to determine whether aggregation would occur at low cell densities and whether the rdar morphotype was involved in this process. The resulting cultures consisted of two populations of cells, aggregated and nonaggregated, with the aggregated cells preferentially displaying rdar morphotype gene expression. The two groups of cells could be separated based on the principle that aggregated cells were producing greater amounts of thin aggregative fimbriae (Tafi or curli). In addition, the aggregated cells retained some physiological characteristics of the rdar morphotype, such as increased resistance to sodium hypochlorite. Competitive infection experiments in mice showed that nonaggregative ΔagfA cells outcompeted rdar-positive wild-type cells in all tissues analyzed, indicating that aggregation via the rdar morphotype was not a virulence adaptation in Salmonella enterica serovar Typhimurium. Furthermore, in vivo imaging experiments showed that Tafi genes were not expressed during infection but were expressed once Salmonella was passed out of the mice into the feces. We hypothesize that the primary role of the rdar morphotype is to enhance Salmonella survival outside the host, thereby aiding in transmission.

scholarly journals Extensive transcriptional and chromatin changes underlie astrocyte maturation in vivo and in culture

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michael Lattke ◽  
Robert Goldstone ◽  
James K. Ellis ◽  
Stefan Boeing ◽  
Jerónimo Jurado-Arjona ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Cell Culture Model ◽  
Functional Maturation ◽  
Culture Model ◽  
Mature Astrocyte ◽  
Transcriptional Changes ◽  
A Cell ◽  
Brain Homeostasis

AbstractAstrocytes have essential functions in brain homeostasis that are established late in differentiation, but the mechanisms underlying the functional maturation of astrocytes are not well understood. Here we identify extensive transcriptional changes that occur during murine astrocyte maturation in vivo that are accompanied by chromatin remodelling at enhancer elements. Investigating astrocyte maturation in a cell culture model revealed that in vitro-differentiated astrocytes lack expression of many mature astrocyte-specific genes, including genes for the transcription factors Rorb, Dbx2, Lhx2 and Fezf2. Forced expression of these factors in vitro induces distinct sets of mature astrocyte-specific transcripts. Culturing astrocytes in a three-dimensional matrix containing FGF2 induces expression of Rorb, Dbx2 and Lhx2 and improves astrocyte maturity based on transcriptional and chromatin profiles. Therefore, extrinsic signals orchestrate the expression of multiple intrinsic regulators, which in turn induce in a modular manner the transcriptional and chromatin changes underlying astrocyte maturation.

scholarly journals Extensive transcriptional and chromatin changes underlie astrocyte maturation in vivo and in culture

2020 ◽  
Author(s):  
Michael Lattke ◽  
Robert Goldstone ◽  
Francois Guillemot
Keyword(s):  
Three Dimensional ◽  
Cell Culture Model ◽  
Culture Model ◽  
Mature Astrocyte ◽  
Transcriptional Changes ◽  
A Cell ◽  
Late Stages ◽  
Brain Homeostasis

SummaryAstrocytes have diverse functions in brain homeostasis. Many of these functions are acquired during late stages of differentiation when astrocytes become fully mature. The mechanisms underlying astrocyte maturation are not well understood. Here we identified extensive transcriptional changes that occur during astrocyte maturation and are accompanied by chromatin remodelling at enhancer elements. Investigating astrocyte maturation in a cell culture model revealed that in vitro-differentiated astrocytes lacked expression of many mature astrocyte-specific genes, including genes for the transcription factors Rorb, Dbx2, Lhx2 and Fezf2. Forced expression of these factors in vitro induced distinct sets of mature astrocytes-specific transcripts. Culturing astrocytes with FGF2 in a three-dimensional gel induced expression of Rorb, Dbx2 and Lhx2 and improved their maturity based on transcriptional and chromatin profiles. Therefore extrinsic signals orchestrate the expression of multiple intrinsic regulators, which in turn induce in a modular manner the transcriptional and chromatin changes underlying astrocyte maturation.

scholarly journals A counter-enzyme complex regulates glutamate metabolism in Bacillus subtilis

2021 ◽  
Author(s):  
Vijay Jayaraman ◽  
D. John Lee ◽  
Nadav Elad ◽  
Shay Vimer ◽  
Michal Sharon ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Glutamate Synthase ◽  
Enzyme Complex ◽  
Primary Role ◽  
Biofilm Growth ◽  
Rich Media ◽  
Sequential Reactions

Multi-enzyme assemblies composed of metabolic enzymes catalyzing sequential reactions are being increasingly studied. Here, we report the discovery of a 1.6 megadalton multi-enzyme complex from Bacillus subtilis composed of two enzymes catalyzing opposite rather than sequential reactions (counter-enzymes): glutamate synthase (GltAB), and glutamate dehydrogenase (GudB), that make and break glutamate, respectively. In vivo and in vitro studies show that the primary role of complex formation is to inhibit GudBs activity as this enzyme is constitutively expressed including in glutamate-limiting conditions. Using cryo-electron microscopy, we elucidated the structure of the complex and the basis of GudBs inhibition. Finally, we show that this complex that exhibits unusual oscillatory progress curves is a necessity for planktonic growth in glutamate-limiting conditions, but is also essential for biofilm growth in glutamate-rich media, suggesting a regulatory role at fluctuating glutamate concentrations.

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