scholarly journals Biocompatibility of Platinum Nanoparticles in Brain ex vivo Models in Physiological and Pathological Conditions

2021 ◽  
Vol 15 ◽  
Author(s):  
Maurizio Gulino ◽  
Sofia Duque Santos ◽  
Ana Paula Pêgo
Keyword(s):  
Pyramidal Cell ◽  
Platinum Nanoparticles ◽  
Cell Activation ◽  
Ex Vivo ◽  
Tissue Response ◽  
Pathological Conditions ◽  
Cell Layers ◽  
Hippocampal Cultures ◽  
The Impact ◽  
The Brain

Platinum nanoparticles (PtNPs) have unique physico-chemical properties that led to their use in many branches of medicine. Recently, PtNPs gathered growing interest as delivery vectors for drugs, biosensors and as surface coating on chronically implanted biomedical devices for improving electrochemical properties. However, there are contradictory statements about their biocompatibility and impact on target organs such as the brain tissue, where these NPs are finding many applications. Furthermore, many of the reported studies are conducted in homeostasis conditions and, consequently, neglect the impact of the pathologic conditions on the tissue response. To expand our knowledge on the effects of PtNPs on neuronal and glial cells, we investigated the acute effects of monodisperse sodium citrate-coated PtNPs on rat organotypic hippocampal cultures in physiological or neuronal excitotoxic conditions induced by kainic acid (KA). The cellular responses of the PtNPs were evaluated through cytotoxic assays and confocal microscopy analysis. To mimic a pathologic scenario, 7-day organotypic hippocampal cultures were exposed to KA for 24 h. Subsequently, PtNPs were added to each slice. We show that incubation of the slices with PtNPs for 24 h, does not severely impact cell viability in normal conditions, with no significant differences when comparing the dentate gyrus (DG), as well as CA3 and CA1 pyramidal cell layers. Such effects are not exacerbated in KA-treated slices, where the presence of PtNPs does not cause additional neuronal propidium iodide (PI) uptake in CA3 and CA1 pyramidal cell layers. However, PtNPs cause microglial cell activation and morphological alterations in CA3 and DG regions indicating the establishment of an inflammatory reaction. Morphological analysis revealed that microglia acquire activated ameboid morphology with loss of ramifications, as a result of their response to PtNPs contact. Surprisingly, this effect is not increased in pathological conditions. Taken together, these results show that PtNPs cause microglia alterations in short-term studies. Additionally, there is no worsening of the tissue response in a neuropathological induced scenario. This work highlights the need of further research to allow for the safe use of PtNPs. Also, it supports the demand of the development of novel and more biocompatible NPs to be applied in the brain.

scholarly journals MALT1 Controls Attenuated Rabies Virus by Inducing Early Inflammation and T Cell Activation in the Brain

2018 ◽  
Vol 92 (8) ◽  
Author(s):  
E. Kip ◽  
J. Staal ◽  
L. Verstrepen ◽  
H. G. Tima ◽  
S. Terryn ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Virus Infection ◽  
Rabies Virus ◽  
T Cell Activation ◽  
Therapeutic Target ◽  
Cell Activation ◽  
Wild Type ◽  
The Impact ◽  
The Brain

ABSTRACTMALT1 is involved in the activation of immune responses, as well as in the proliferation and survival of certain cancer cells. MALT1 acts as a scaffold protein for NF-κB signaling and a cysteine protease that cleaves substrates, further promoting the expression of immunoregulatory genes. Deregulated MALT1 activity has been associated with autoimmunity and cancer, implicating MALT1 as a new therapeutic target. Although MALT1 deficiency has been shown to protect against experimental autoimmune encephalomyelitis, nothing is known about the impact of MALT1 on virus infection in the central nervous system. Here, we studied infection with an attenuated rabies virus, Evelyn-Rotnycki-Abelseth (ERA) virus, and observed increased susceptibility with ERA virus in MALT1−/−mice. Indeed, after intranasal infection with ERA virus, wild-type mice developed mild transient clinical signs with recovery at 35 days postinoculation (dpi). Interestingly, MALT1−/−mice developed severe disease requiring euthanasia at around 17 dpi. A decreased induction of inflammatory gene expression and cell infiltration and activation was observed in MALT1−/−mice at 10 dpi compared to MALT1+/+infected mice. At 17 dpi, however, the level of inflammatory cell activation was comparable to that observed in MALT1+/+mice. Moreover, MALT1−/−mice failed to produce virus-neutralizing antibodies. Similar results were obtained with specific inactivation of MALT1 in T cells. Finally, treatment of wild-type mice with mepazine, a MALT1 protease inhibitor, also led to mortality upon ERA virus infection. These data emphasize the importance of early inflammation and activation of T cells through MALT1 for controlling the virulence of an attenuated rabies virus in the brain.IMPORTANCERabies virus is a neurotropic virus which can infect any mammal. Annually, 59,000 people die from rabies. Effective therapy is lacking and hampered by gaps in the understanding of virus pathogenicity. MALT1 is an intracellular protein involved in innate and adaptive immunity and is an interesting therapeutic target because MALT1-deregulated activity has been associated with autoimmunity and cancers. The role of MALT1 in viral infection is, however, largely unknown. Here, we study the impact of MALT1 on virus infection in the brain, using the attenuated ERA rabies virus in different models of MALT1-deficient mice. We reveal the importance of MALT1-mediated inflammation and T cell activation to control ERA virus, providing new insights in the biology of MALT1 and rabies virus infection.

scholarly journals SCA-1 micro-heterogeneity in the fate decision of dystrophic fibro/adipogenic progenitors

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Giulio Giuliani ◽  
Simone Vumbaca ◽  
Claudia Fuoco ◽  
Cesare Gargioli ◽  
Ezio Giorda ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Genetic Diseases ◽  
Proliferating Cells ◽  
Pathological Conditions ◽  
Fate Decision ◽  
Cell To Cell Variability ◽  
The Impact ◽  
Dystrophic Mice ◽  
Different Levels

AbstractThe term micro-heterogeneity refers to non-genetic cell to cell variability observed in a bell-shaped distribution of the expression of a trait within a population. The contribution of micro-heterogeneity to physiology and pathology remains largely uncharacterised. To address such an issue, we investigated the impact of heterogeneity in skeletal muscle fibro/adipogenic progenitors (FAPs) isolated from an animal model of Duchenne muscular dystrophy (DMD), the mdx mouse. FAPs play an essential role in muscle homoeostasis. However, in pathological conditions or ageing, they are the source of intramuscular infiltrations of fibrotic or adipose tissue. By applying a multiplex flow cytometry assay, we characterised and purified from mdx muscles two FAP cell states expressing different levels of SCA-1. The two cell states are morphologically identical and repopulate each other after several growth cycles. However, they differ in their in vitro behaviour. Cells expressing higher levels of SCA-1 (SCA1-High-FAPs) differentiate more readily into adipocytes while, when exposed to a fibrogenic stimulation, increase the expression of Col1a1 and Timp1 mRNA. A transcriptomic analysis confirmed the adipogenic propensity of SCA1-High-FAPs. In addition, SCA1-High-FAPs proliferate more extensively ex vivo and display more proliferating cells in dystrophic muscles in comparison to SCA1-Low-FAPs. Adipogenesis of both FAP cell states is inhibited in vitro by leucocytes from young dystrophic mice, while leucocytes isolated from aged dystrophic mice are less effective in limiting the adipogenesis of SCA1-High-FAPs suggesting a differential regulatory effect of the microenvironment on micro-heterogeneity. Our data suggest that FAP micro-heterogeneity is modulated in pathological conditions and that this heterogeneity in turn may impact on the behaviour of interstitial mesenchymal cells in genetic diseases.

scholarly journals Acute and chronic stage adaptations of vascular architecture and cerebral blood flow in a mouse model of TBI

2018 ◽  
Author(s):  
Joe Steinman ◽  
Lindsay S. Cahill ◽  
Margaret M. Koletar ◽  
Bojana Stefanovic ◽  
John G. Sled
Keyword(s):  
Blood Flow ◽  
Ex Vivo ◽  
Vessel Density ◽  
Vascular Architecture ◽  
Two Photon ◽  
Brain Vasculature ◽  
The Impact ◽  
The Brain ◽  
Time Point

AbstractThe 3D organization of cerebral blood vessels determines the overall capacity of the cerebral circulation to meet the metabolic requirements of the brain. This study used Arterial Spin Labeling (ASL) MRI with a hypercapnic challenge and ex vivo Serial Two-Photon Tomography (STPT) to examine the relationship between blood flow and 3D microvascular structure following traumatic brain injury (TBI) in a mouse. Mice were exposed to a controlled cortical impact TBI and allowed to recover for either 1 day or 4 weeks. At each time point, ASL MRI was performed to quantify cerebral perfusion and the brain vasculature was imaged in 3D with STPT. Registration of ASL to STPT enabled flow changes to be related to the underlying microvascular structure in each ASL voxel. Hypoperfusion under rest and hypercapnia was observed both 1 day and 4 weeks post-TBI. Vessel density and vascular volume were reduced 1 day post-TBI, recovering by 4 weeks; however, the reorganized vasculature at the latter time point possessed an abnormal radial pattern. Our findings demonstrate functionally significant long-term changes in the vascular architecture following injury and illustrate why metrics beyond traditional measures of vessel density are required to understand the impact of vascular structure on function.

Impact of hypoxia on immune cells in human atherosclerotic plaques

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
D Vorobyeva ◽  
A Lebedeva ◽  
A Elizarova ◽  
E Maryukhnich ◽  
V Gontarenko ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Ex Vivo ◽  
Atherosclerotic Plaques ◽  
Funding Source ◽  
Ex Vivo Model ◽  
Activation Markers ◽  
Hypoxic Conditions ◽  
The Impact

Abstract Background Inflammation plays a major role in atherosclerotic plaques' progression and was shown to be associated with the formation of hypoxic areas within the plaques. However, the data about the impact of hypoxia on atherosclerosis are contradictory, in part due to inadequacy of in vitro and animal models to reproduce faithfully the complexity of human atherosclerotic plaques. Purpose The aim of this study was to investigate the effect of hypoxia on immune status in the ex vivo system of human atherosclerotic plaques. Methods We collected 25 atherosclerotic plaques from patients undergoing carotid endarterectomy, cut plaques into ring-shaped slices and cultured them for 24 hours at the liquid/air interface on collagen sponges under hypoxic (2% O2) and normoxic (12% O2) conditions. After 24 hours we evaluated T-cell activation status within plaques according to the presence of membrane activation markers by means of multiparametric flow cytometry and the activity of cytokine production using xMAP technology. Results We found that CD8 T cells from human atherosclerotic plaques cultured under hypoxic conditions compared to normoxic conditions have a decreased expression of CD69 activation marker (42.7 [34.3; 50.9]% vs 53.8 [33.3; 63.3]%, n=10, p=0.047) and lower level of CD69 and HLA-DR coexpression (16.0 [10.5; 22.3] vs 22.6 [11.3; 28.2], n=10, p=0.02). CD4 T cells did not show any significant changes in expression of activation markers under hypoxia. Hypoxic conditions also resulted in a reduced IL-10 production (104.2 [53.8; 170.9] vs 235.2 [158.5; 335.3] pg/100 mg of tissue, n=20, p=0.0001) and increased VEGF production (116.1 [79.8; 253.5] vs 89.9 [71.1; 148.8] pg/100 mg of tissue, n=20, p=0.033). Conclusions Our results indicate that hypoxia causes a decrease in the activity of cytotoxic T cells and increases stimuli for angiogenesis within the human atherosclerotic plaques. The established ex vivo model of human atherosclerotic plaques culture under hypoxia enables further studies of the hypoxia impact on atherosclerosis. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Russian Science Foundation grant

scholarly journals Ex vivo modelling of PD-1/PD-L1 immune checkpoint blockade under acute, chronic, and exhaustion-like conditions of T-cell stimulation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander Roberts ◽  
Lindsay Bentley ◽  
Tina Tang ◽  
Fay Stewart ◽  
Chiara Pallini ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Immune Checkpoint ◽  
Inflammatory Cytokine ◽  
Cell Activation ◽  
Ex Vivo ◽  
In Vitro Assays ◽  
The Impact

AbstractBlockade of PD-1/PD-L1 interactions is proving an exciting, durable therapeutic modality in a range of cancers whereby T cells are released from checkpoint inhibition to revive their inherent anti-tumour activity. Here we have studied various ways to model ex vivo T cell function in order to compare the impact of the clinically utilised anti-PD-1 antibody, pembrolizumab (Keytruda) on the activation of human T cells: focussing on the release of pro-inflammatory IFNγ and anti-inflammatory IL-10 to assess functionality. Firstly, we investigated the actions of pembrolizumab in an acute model of T-cell activation with either immature or mature allogeneic dendritic cells (DCs); pembrolizumab enhanced IFNγ and IL-10 release from purified CD4+ T-cells in the majority of donors with a bias towards pro-inflammatory cytokine release. Next, we modelled the impact of pembrolizumab in settings of more chronic T-cell activation. In a 7-day antigen-specific response to EBV peptides, the presence of pembrolizumab resulted in a relatively modest increase in both IFNγ and IL-10 release. Where pembrolizumab was assessed against long-term stimulated CD4+ cells that had up-regulated the exhaustion markers TIM-3 and PD-1, there was a highly effective enhancement of the otherwise exhausted response to allogeneic DCs with respect to IFNγ production. By contrast, the restoration of IL-10 production was considerably more limited. Finally, to assess a direct clinical relevance we investigated the consequence of PD-1/PD-L1 blockade in the disease setting of dissociated cells from lung and colon carcinomas responding to allogeneic DCs: here, pembrolizumab once more enhanced IFNγ production from the majority of tumour preparations whereas, again, the increase in IL-10 release was modest at best. In conclusion, we have shown that the contribution of PD-1—revealed by using a canonical blocking antibody to interrupt its interaction with PD-L1—to the production of an exemplar pro- and anti-inflammatory cytokine, respectively, depends in magnitude and ratio on the particular stimulation setting and activation status of the target T cell. We have identified a number of in vitro assays with response profiles that mimic features of dissociated cell populations from primary tumours thereby indicating these represent disease-relevant functional assays for the screening of immune checkpoint inhibitors in current and future development. Such in vitro assays may also support patient stratification of those likely to respond to immuno-oncology therapies in the wider population.

scholarly journals The Role of AhR in the Hallmarks of Brain Aging: Friend and Foe

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2729
Author(s):  
Emmanuel S. Ojo ◽  
Shelley A. Tischkau
Keyword(s):  
Oxidative Stress ◽  
Signaling Pathways ◽  
Aging Process ◽  
Cell Activation ◽  
Brain Aging ◽  
Aryl Hydrocarbon ◽  
Glial Cell Activation ◽  
The Impact ◽  
The Brain

In recent years, aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, has been considered to be involved in aging phenotypes across several species. This receptor is a highly conserved biosensor that is activated by numerous exogenous and endogenous molecules, including microbiota metabolites, to mediate several physiological and toxicological functions. Brain aging hallmarks, which include glial cell activation and inflammation, increased oxidative stress, mitochondrial dysfunction, and cellular senescence, increase the vulnerability of humans to various neurodegenerative diseases. Interestingly, many studies have implicated AhR signaling pathways in the aging process and longevity across several species. This review provides an overview of the impact of AhR pathways on various aging hallmarks in the brain and the implications for AhR signaling as a mechanism in regulating aging-related diseases of the brain. We also explore how the nature of AhR ligands determines the outcomes of several signaling pathways in brain aging processes.

scholarly journals Does COVID-19 Affect Adult Neurogenesis? A Neurochemical Perspective

2021 ◽  
Author(s):  
Jayakumar Saikarthik ◽  
Ilango Saraswathi ◽  
Abdulrahman A. Al-Atram
Keyword(s):  
Adult Neurogenesis ◽  
Cell Activation ◽  
Immune Cell ◽  
Neuropsychiatric Symptoms ◽  
Brain Regions ◽  
Immune Cell Activation ◽  
Brain Involvement ◽  
The Impact ◽  
The Brain

COVID-19 has been found to cause neuropsychiatric symptoms which indicate brain involvement. SARS-CoV-2 may enter the brain by damaging and penetrating olfactory mucosa and via other possible routes like damaged blood–brain barrier, and hematologic spread. With SARS-CoV-2 having a higher affinity to ACE2 receptors, brain regions that have higher ACE2 receptors like the hippocampus, are more vulnerable to the effect of the viral invasion. In addition, immune cell activation, an important feature of COVID-19, leads to cytokine storm which causes neurotoxicity, neuroinflammation, and neurodegeneration. Impaired adult neurogenesis is related to many psychiatric disorders including depression, bipolar disorder, anxiety disorder, schizophrenia, and PTSD. It is known to be related to the depletion of neurotransmitters, dopamine, serotonin, norepinephrine, GABA, and glutamate which play a major role in adult neurogenesis. A recent study reveals that SSRI which acts by increasing serotonin is proven beneficial in COVID-19 patients. Thus, the current chapter will discuss the impact of COVID-19 on adult neurogenesis with emphasis on the role of ACE2 and neurotransmitters.

scholarly journals SCA-1 micro-heterogeneity in the fate decision of dystrophic fibro/adipogenic progenitors

2020 ◽  
Author(s):  
Giulio Giuliani ◽  
Simone Vumbaca ◽  
Claudia Fuoco ◽  
Cesare Gargioli ◽  
Ezio Giorda ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Genetic Diseases ◽  
Proliferating Cells ◽  
Pathological Conditions ◽  
Fate Decision ◽  
Muscle Homeostasis ◽  
Cell To Cell Variability ◽  
The Impact ◽  
Dystrophic Mice

AbstractThe term micro-heterogeneity refers to non-genetic cell to cell variability observed in a bell-shaped distribution of the expression of a trait within a population. The contribution of micro-heterogeneity to physiology and pathology remains largely uncharacterised. To address such an issue, we investigated the impact of heterogeneity in skeletal muscle fibro/adipogenic progenitors (FAPs) isolated from an animal model of Duchenne muscular dystrophy (DMD), the mdx mouse. FAPs play an essential role in muscle homeostasis. However, in pathological conditions or ageing, they are the source of intramuscular infiltrations of fibrotic or adipose tissue. By applying a multiplex flow cytometry assay, we characterised and purified from mdx muscles two FAP cell states expressing different levels of SCA-1. The two cell states are morphologically identical and repopulate each other after several growth cycles. However, they differ in their in vitro behaviour. Cells expressing higher levels of SCA-1 (SCA1-High-FAPs) differentiate more readily into adipocytes while, when exposed to a fibrogenic stimulation, increase the expression of COL1A1 mRNA. In addition, SCA1-High-FAPs proliferate more extensively ex vivo and display more proliferating cells in dystrophic muscles. Adipogenesis of FAP cell states is inhibited in vitro by leukocytes from young dystrophic mice, while leukocytes isolated from aged dystrophic mice are less effective in limiting the adipogenesis of SCA1-High-FAPs suggesting a differential regulatory effect of the microenvironment on micro-heterogeneity. Our data suggest that FAP micro-heterogeneity is modulated in pathological conditions and that this heterogeneity in turn may impact on the behaviour of mesenchymal cells in genetic diseases.

Distribution of Brain Strain in the Cerebrum for Laboratory Impacts to Ice Hockey Goaltender Masks

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
J. Michio Clark ◽  
Andrew Post ◽  
T. Blaine Hoshizaki ◽  
Michael D. Gilchrist
Keyword(s):  
Brain Regions ◽  
Ice Hockey ◽  
Tissue Response ◽  
Loading Conditions ◽  
Impact Site ◽  
Trauma Model ◽  
The University ◽  
The Impact ◽  
Impact Events ◽  
The Brain

Concussions are among the most common injuries sustained by goaltenders. Concussive injuries are characterized by impairment to neurological function which can affect many different brain regions. Understanding how different impact loading conditions (event type and impact site) affect the brain tissue response may help identify what kind of impacts create a high risk of injury to specific brain regions. The purpose of this study was to examine the influence of different impact conditions on the distribution of brain strain for ice hockey goaltender impacts. An instrumented headform was fitted with an ice hockey goaltender mask and impacted under a protocol which was developed using video analysis of real world ice hockey goaltender concussions for three different impact events (collision, puck, and fall). The resulting kinematic response served as input into the University College Dublin Brain Trauma Model (UCDBTM), which calculated maximum principal strain (MPS) in the cerebrum. Strain subsets were then determined and analyzed. Resulting peak strains (0.124–0.328) were found to be within the range for concussion reported in the literature. The results demonstrated that falls and collisions produced larger strain subsets in the cerebrum than puck impacts which is likely a reflection of longer impact duration for falls and collisions than puck impacts. For each impact event, impact site was also found to produce strain subsets of varying size and configuration. The results of this study suggest that the location and number of brain regions which can be damaged depend on the loading conditions of the impact.

scholarly journals Perturbed Brain Glucose Metabolism Caused by Absent SIRT3 Activity

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2348
Author(s):  
Tibor Kristian ◽  
Arman J. Karimi ◽  
Adam Fearnow ◽  
Jaylyn Waddell ◽  
Mary C. McKenna
Keyword(s):  
Glucose Metabolism ◽  
Ex Vivo ◽  
Tca Cycle ◽  
13C Nmr Spectroscopy ◽  
Mitochondrial Enzymes ◽  
Post Translational Modification ◽  
Oxidative Energy Metabolism ◽  
Activity Of Enzymes ◽  
The Impact ◽  
The Brain

Acetylation is a post-translational modification that regulates the activity of enzymes fundamentally involved in cellular and mitochondrial bioenergetic metabolism. NAD+ dependent deacetylase sirtuin 3 (SIRT3) is localized to mitochondria where it plays a key role in regulating acetylation of TCA cycle enzymes and the mitochondrial respiratory complexes. Although the SIRT3 target proteins in mitochondria have been identified, the effect of SIRT3 activity on mitochondrial glucose metabolism in the brain remains elusive. The impact of abolished SIRT3 activity on glucose metabolism was determined in SIRT3 knockout (KO) and wild type (WT) mice injected with [1,6-13C]glucose using ex vivo 13C-NMR spectroscopy. The 1H-NMR spectra and amino acid analysis showed no differences in the concentration of lactate, glutamate, alanine, succinate, or aspartate between SIRT3 KO and WT mice. However, glutamine, total creatine (Cr), and GABA were lower in SIRT3 KO brain. Incorporation of label from [1,6-13C]glucose metabolism into lactate or alanine was not affected in SIRT3 KO brain. However, the incorporation of the label into all isotopomers of glutamate, glutamine, GABA and aspartate was lower in SIRT3 KO brain, reflecting decreased activity of mitochondrial and TCA cycle metabolism in both neurons and astrocytes. This is most likely due to hyperacetylation of mitochondrial enzymes due to suppressed SIRT3 activity in the brain of SIRT3 KO mice. Thus, the absence of Sirt3 results in impaired mitochondrial oxidative energy metabolism and neurotransmitter synthesis in the brain. Since the SIRT3 activity is NAD+ dependent, these results might parallel changes in glucose metabolism under pathologic reduction in mitochondrial NAD+ pools.

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