Region specific contribution of ASIC2 to acidosis-and ischemia-induced neuronal injury

Acidosis in the brain plays a critical role in neuronal injury in neurological diseases, including brain ischemia. One key mediator of acidosis-induced neuronal injury is the acid-sensing ion channels (ASICs). Current literature has focused on ASIC1a when studying acid signaling. The importance of ASIC2, which is also widely expressed in the brain, has not been appreciated. We found here a region-specific effect of ASIC2 on acid-mediated responses. Deleting ASIC2 reduced acid-activated current in cortical and striatal neurons, but had no significant effect in cerebellar granule neurons. In addition, we demonstrated that ASIC2 was important for ASIC1a expression, and that ASIC2a but not 2b facilitated ASIC1a surface trafficking in the brain. Further, we showed that ASIC2 deletion attenuated acidosis/ischemia-induced neuronal injury in organotypic hippocampal slices but had no effect in organotypic cerebellar slices. Consistent with an injurious role of ASIC2, we showed that ASIC2 deletion significantly protected the mouse brain from ischemic damage in vivo. These data suggest a critical region-specific contribution of ASIC2 to neuronal injury and reveal an important functional difference between ASIC2a and 2b in the brain.

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The Potential Roles of Blood–Brain Barrier and Blood–Cerebrospinal Fluid Barrier in Maintaining Brain Manganese Homeostasis

Nutrients ◽

10.3390/nu13061833 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1833

Author(s):

Shannon Morgan McCabe ◽

Ningning Zhao

Keyword(s):

Cerebrospinal Fluid ◽

Blood Brain Barrier ◽

Blood Circulation ◽

Critical Role ◽

Systemic Circulation ◽

Brain Parenchyma ◽

Brain Barrier ◽

Blood Brain ◽

The Brain

Manganese (Mn) is a trace nutrient necessary for life but becomes neurotoxic at high concentrations in the brain. The brain is a “privileged” organ that is separated from systemic blood circulation mainly by two barriers. Endothelial cells within the brain form tight junctions and act as the blood–brain barrier (BBB), which physically separates circulating blood from the brain parenchyma. Between the blood and the cerebrospinal fluid (CSF) is the choroid plexus (CP), which is a tissue that acts as the blood–CSF barrier (BCB). Pharmaceuticals, proteins, and metals in the systemic circulation are unable to reach the brain and spinal cord unless transported through either of the two brain barriers. The BBB and the BCB consist of tightly connected cells that fulfill the critical role of neuroprotection and control the exchange of materials between the brain environment and blood circulation. Many recent publications provide insights into Mn transport in vivo or in cell models. In this review, we will focus on the current research regarding Mn metabolism in the brain and discuss the potential roles of the BBB and BCB in maintaining brain Mn homeostasis.

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IKKβ slows Huntington’s disease progression in R6/1 mice

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1814246116 ◽

2019 ◽

Vol 116 (22) ◽

pp. 10952-10961 ◽

Cited By ~ 4

Author(s):

Joseph Ochaba ◽

Gianna Fote ◽

Marketta Kachemov ◽

Soe Thein ◽

Sylvia Y. Yeung ◽

...

Keyword(s):

Huntington's Disease ◽

Huntington’S Disease ◽

Neuronal Degeneration ◽

Neuronal Injury ◽

Therapeutic Interventions ◽

Striatal Neurons ◽

Microglial Response ◽

Relationship Of ◽

The Impact

Neuroinflammation is an important contributor to neuronal pathology and death in neurodegenerative diseases and neuronal injury. Therapeutic interventions blocking the activity of the inflammatory kinase IKKβ, a key regulator of neuroinflammatory pathways, is protective in several animal models of neurodegenerative disease and neuronal injury. In Huntington’s disease (HD), however, significant questions exist as to the impact of blocking or diminishing the activity of IKKβ on HD pathology given its potential role in Huntingtin (HTT) degradation. In cell culture, IKKβ phosphorylates HTT serine (S) 13 and activates HTT degradation, a process that becomes impaired with polyQ expansion. To investigate the in vivo relationship of IKKβ to HTT S13 phosphorylation and HD progression, we crossed conditional tamoxifen-inducible IKKβ knockout mice with R6/1 HD mice. Behavioral assays in these mice showed a significant worsening of HD pathological phenotypes. The increased behavioral pathology correlated with reduced levels of endogenous mouse full-length phospho-S13 HTT, supporting the importance of IKKβ in the phosphorylation of HTT S13 in vivo. Notably, many striatal autophagy genes were up-regulated in HD vs. control mice; however, IKKβ knockout partially reduced this up-regulation in HD, increased striatal neurodegeneration, and enhanced an activated microglial response. We propose that IKKβ is protective in striatal neurons early in HD progression via phosphorylation of HTT S13. As IKKβ is also required for up-regulation of some autophagy genes and HTT is a scaffold for selective autophagy, IKKβ may influence autophagy through multiple mechanisms to maintain healthy striatal function, thereby reducing neuronal degeneration to slow HD onset.

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Locus Coeruleus Magnetic Resonance Imaging in Neurological Diseases

Current Neurology and Neuroscience Reports ◽

10.1007/s11910-020-01087-7 ◽

2020 ◽

Vol 21 (1) ◽

Author(s):

Alessandro Galgani ◽

Francesco Lombardo ◽

Daniele Della Latta ◽

Nicola Martini ◽

Ubaldo Bonuccelli ◽

...

Keyword(s):

Locus Coeruleus ◽

Neurological Disorders ◽

Potential Role ◽

Neurological Diseases ◽

Mri Findings ◽

Promising Tool ◽

Experimental Tool ◽

Early Biomarker ◽

The Brain

Abstract Purpose of Review Locus coeruleus (LC) is the main noradrenergic nucleus of the brain, and its degeneration is considered to be key in the pathogenesis of neurodegenerative diseases. In the last 15 years,MRI has been used to assess LC in vivo, both in healthy subjects and in patients suffering from neurological disorders. In this review, we summarize the main findings of LC-MRI studies, interpreting them in light of preclinical and histopathological data, and discussing its potential role as diagnostic and experimental tool. Recent findings LC-MRI findings were largely in agreement with neuropathological evidences; LC signal showed to be not significantly affected during normal aging and to correlate with cognitive performances. On the contrary, a marked reduction of LC signal was observed in patients suffering from neurodegenerative disorders, with specific features. Summary LC-MRI is a promising tool, which may be used in the future to explore LC pathophysiology as well as an early biomarker for degenerative diseases.

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Magnetic Nanoparticles as In Vivo Tracers for Alzheimer’s Disease

Magnetochemistry ◽

10.3390/magnetochemistry6010013 ◽

2020 ◽

Vol 6 (1) ◽

pp. 13

Author(s):

Bhargy Sharma ◽

Konstantin Pervushin

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Early Diagnosis ◽

Contrast Agents ◽

Neurological Diseases ◽

Pulse Sequences ◽

Experimental Conditions ◽

Magnetic Resonance Imaging Mri ◽

The Brain

Drug formulations and suitable methods for their detection play a very crucial role in the development of therapeutics towards degenerative neurological diseases. For diseases such as Alzheimer’s disease, magnetic resonance imaging (MRI) is a non-invasive clinical technique suitable for early diagnosis. In this review, we will discuss the different experimental conditions which can push MRI as the technique of choice and the gold standard for early diagnosis of Alzheimer’s disease. Here, we describe and compare various techniques for administration of nanoparticles targeted to the brain and suitable formulations of nanoparticles for use as magnetically active therapeutic probes in drug delivery targeting the brain. We explore different physiological pathways involved in the transport of such nanoparticles for successful entry in the brain. In our lab, we have used different formulations of iron oxide nanoparticles (IONPs) and protein nanocages as contrast agents in anatomical MRI of an Alzheimer’s disease (AD) brain. We compare these coatings and their benefits to provide the best contrast in addition to biocompatibility properties to be used as sustainable drug-release systems. In the later sections, the contrast enhancement techniques in MRI studies are discussed. Examples of contrast-enhanced imaging using advanced pulse sequences are discussed with the main focus on important studies in the field of neurological diseases. In addition, T1 contrast agents such as gadolinium chelates are compared with the T2 contrast agents mainly made of superparamagnetic inorganic metal nanoparticles.

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Percutaneous Intracerebral Navigation by Duty-Cycled Spinning of Flexible Bevel-Tipped Needles

Neurosurgery ◽

10.1227/neu.0b013e3181ec1551 ◽

2010 ◽

Vol 67 (4) ◽

pp. 1117-1123 ◽

Cited By ~ 44

Author(s):

Johnathan A Engh ◽

Davneet S Minhas ◽

Douglas Kondziolka ◽

Cameron N Riviere

Keyword(s):

Image Guidance ◽

Neurological Diseases ◽

Steering System ◽

Needle Steering ◽

Future Studies ◽

Area Of Interest ◽

Cadaver Testing ◽

The Brain ◽

Cadaveric Model

Abstract BACKGROUND: Intracerebral drug delivery using surgically placed microcatheters is a growing area of interest for potential treatment of a wide variety of neurological diseases, including tumors, neurodegenerative disorders, trauma, epilepsy, and stroke. Current catheter placement techniques are limited to straight trajectories. The development of an inexpensive system for flexible percutaneous intracranial navigation may be of significant clinical benefit. OBJECTIVE: Utilizing duty-cycled spinning of a flexible bevel-tipped needle, the authors devised and tested a means of achieving nonlinear trajectories for the navigation of catheters in the brain, which may be applicable to a wide variety of neurological diseases. METHODS: Exploiting the bending tendency of bevel-tipped needles due to their asymmetry, the authors devised and tested a means of generating curvilinear trajectories by spinning a needle with a variable duty cycle (ie, in on-off fashion). The technique can be performed using image guidance, and trajectories can be adjusted intraoperatively via joystick. Fifty-eight navigation trials were performed during cadaver testing to demonstrate the efficacy of the needle-steering system and to test its precision. RESULTS: The needle-steering system achieved a target acquisition error of 2 ± 1 mm, while demonstrating the ability to reach multiple targets from one burr hole using trajectories of varying curvature. CONCLUSION: The accuracy of the needle-steering system was demonstrated in a cadaveric model. Future studies will determine the safety of the device in vivo.

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The ATF6β-calreticulin axis promotes neuronal survival under endoplasmic reticulum stress and excitotoxicity

10.1101/2021.02.01.429116 ◽

2021 ◽

Author(s):

Dinh Thi Nguyen ◽

Thuong Manh Le ◽

Tsuyoshi Hattori ◽

Mika Takarada-Iemata ◽

Hiroshi Ishii ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Er Stress ◽

Hippocampal Neurons ◽

Neuronal Survival ◽

Binding Capacity ◽

Critical Role ◽

Er Stress Response ◽

The Central Nervous System ◽

The Brain

AbstractWhile ATF6α plays a central role in the endoplasmic reticulum (ER) stress response, the function of ATF6β is largely unknown. Here, we demonstrate that ATF6β is highly expressed in the hippocampus of the brain, and specifically regulates the expression of calreticulin, a molecular chaperone in the ER with a high Ca2+-binding capacity. Calreticulin expression was reduced to ~50% in the central nervous system of Atf6b−/− mice, and restored by ATF6β. Analysis using cultured hippocampal neurons revealed that ATF6β deficiency reduced Ca2+ stores in the ER and enhanced ER stress-induced death, which was rescued by ATF6β, calreticulin, Ca2+-modulating reagents such as BAPTA-AM and 2-APB, and ER stress inhibitor salubrinal. In vivo, kainate-induced neuronal death was enhanced in hippocampi of Atf6b−/− and Calr+/− mice, and restored by 2-APB and salubrinal. These results suggest that the ATF6β-calreticulin axis plays a critical role in the neuronal survival by improving Ca2+ homeostasis under ER stress.

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Cell type-specific biotin labeling in vivo resolves regional neuronal proteomic differences in mouse brain

10.1101/2021.08.03.454921 ◽

2021 ◽

Author(s):

Sruti Rayaprolu ◽

Sara Bitarafan ◽

Ranjita Betarbet ◽

Sydney N Sunna ◽

Lihong Cheng ◽

...

Keyword(s):

Mouse Brain ◽

Neurological Diseases ◽

Neuronal Cell ◽

Cell Types ◽

Proteomic Profiling ◽

Cell Type ◽

Specific Expression ◽

Cell Type Specific ◽

The Brain

Isolation and proteomic profiling of brain cell types, particularly neurons, pose several technical challenges which limit our ability to resolve distinct cellular phenotypes in neurological diseases. Therefore, we generated a novel mouse line that enables cell type-specific expression of a biotin ligase, TurboID, via Cre-lox strategy for in vivo proximity-dependent biotinylation of proteins. Using adenoviral-based and transgenic approaches, we show striking protein biotinylation in neuronal cell bodies and axons throughout the mouse brain. We quantified more than 2,000 neuron-derived proteins following enrichment that mapped to numerous subcellular compartments. Synaptic, transmembrane transporters, ion channel subunits, and disease-relevant druggable targets were among the most significantly enriched proteins. Remarkably, we resolved brain region-specific proteomic profiles of Camk2a neurons with distinct functional molecular signatures and disease associations that may underlie regional neuronal vulnerability. Leveraging the neuronal specificity of this in vivo biotinylation strategy, we used an antibody-based approach to uncover regionally unique patterns of neuron-derived signaling phospho-proteins and cytokines, particularly in the cortex and cerebellum. Our work provides a proteomic framework to investigate cell type-specific mechanisms driving physiological and pathological states of the brain as well as complex tissues beyond the brain.

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A Comparative Study on Delivery of Externally Attached DNA by Papillomavirus VLPs and Pseudoviruses

Vaccines ◽

10.3390/vaccines9121501 ◽

2021 ◽

Vol 9 (12) ◽

pp. 1501

Author(s):

Sarah Brendle ◽

Nancy Cladel ◽

Karla Balogh ◽

Samina Alam ◽

Neil Christensen ◽

...

Keyword(s):

Critical Role ◽

Specific Effect ◽

Dna Delivery ◽

Dna Uptake ◽

In Vivo Models ◽

Cottontail Rabbit ◽

Species Specific ◽

Dna Delivery Vehicle

Human papillomavirus (HPV) 16 capsids have been chosen as a DNA delivery vehicle in many studies. Our preliminary studies suggest that HPV58 capsids could be better vehicles than HPV16 capsids to deliver encapsidated DNA in vitro and in vivo. In the current study, we compared HPV16, HPV58, and the cottontail rabbit papillomavirus (CRPV) capsids either as L1/L2 VLPs or pseudoviruses (PSVs) to deliver externally attached GFP-expressing DNA. Both rabbit and human cells were used to test whether there was a species-specific effect. DNA delivery efficiency was determined by quantifying either GFP-expressing cell populations or mean fluorescent intensities (MFI) by flow cytometry. Interestingly, CRPV and 58-VLPs and PSVs were significantly more efficient at delivering attached DNA when compared to 16-VLPs and PSVs. A capsid/DNA ratio of 2:1 showed the highest efficiency for delivering external DNA. The PSVs with papillomavirus DNA genomes also showed higher efficiency than those with irrelevant plasmid DNA. HPV16L1/58L2 hybrid VLPs displayed increased efficiency compared to HPV58L1/16L2 VLPs, suggesting that L2 may play a critical role in the delivery of attached DNA. Additionally, we demonstrated that VLPs increased in vivo infectivity of CRPV DNA in rabbits. We conclude that choosing CRPV or 58 capsids to deliver external DNA could improve DNA uptake in in vitro and in vivo models.

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JC Polyomavirus Uses Extracellular Vesicles To Infect Target Cells

mBio ◽

10.1128/mbio.00379-19 ◽

2019 ◽

Vol 10 (2) ◽

Cited By ~ 22

Author(s):

Jenna Morris-Love ◽

Gretchen V. Gee ◽

Bethany A. O’Hara ◽

Benedetta Assetta ◽

Abigail L. Atkinson ◽

...

Keyword(s):

Progressive Multifocal Leukoencephalopathy ◽

Extracellular Vesicles ◽

Critical Role ◽

Outer Side ◽

Target Cells ◽

Alternative Mechanism ◽

Jc Polyomavirus ◽

Virus Receptors ◽

The Brain

ABSTRACTThe endemic human JC polyomavirus (JCPyV) causes progressive multifocal leukoencephalopathy in immune-suppressed patients. The mechanisms of virus infectionin vivoare not understood because the major target cells for virus in the brain do not express virus receptors and do not bind virus. We found that JCPyV associates with extracellular vesicles (EVs) and can infect target cells independently of virus receptors. Virus particles were found packaged inside extracellular vesicles and attached to the outer side of vesicles. Anti-JCPyV antisera reduced infection by purified virus but had no effect on infection by EV-associated virus. Treatment of cells with the receptor-destroying enzyme neuraminidase inhibited infection with purified virus but did not inhibit infection by EV-associated virus. Mutant pseudoviruses defective in sialic acid receptor binding could not transduce cells as purified pseudovirions but could do so when associated with EVs. This alternative mechanism of infection likely plays a critical role in the dissemination and spread of JCPyV both to and within the central nervous system.IMPORTANCEJC polyomavirus (JCPyV) is a ubiquitous human pathogen that causes progressive multifocal leukoencephalopathy (PML), a severe and often fatal neurodegenerative disease in immunocompromised or immunomodulated patients. The mechanisms responsible for initiating infection in susceptible cells are not completely known. The major attachment receptor for the virus, lactoseries tetrasaccharide c (LSTc), is paradoxically not expressed on oligodendrocytes or astrocytes in human brain, and virus does not bind to these cells. Because these are the major cell types targeted by the virus in the brain, we hypothesized that alternative mechanisms of infection must be responsible. Here we provide evidence that JCPyV is packaged in extracellular vesicles from infected cells. Infection of target cells by vesicle-associated virus is not dependent on LSTc and is not neutralized by antisera directed against the virus. This is the first demonstration of a polyomavirus using extracellular vesicles as a means of transmission.

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Exaggerated inflammation, impaired host defense, and neuropathology in progranulin-deficient mice

Journal of Experimental Medicine ◽

10.1084/jem.20091568 ◽

2009 ◽

Vol 207 (1) ◽

pp. 117-128 ◽

Cited By ~ 272

Author(s):

Fangfang Yin ◽

Rebecca Banerjee ◽

Bobby Thomas ◽

Ping Zhou ◽

Liping Qian ◽

...

Keyword(s):

Host Defense ◽

Hippocampal Slices ◽

Interleukin 10 ◽

Biological Processes ◽

Listeria Monocytogenes Infection ◽

The Brain ◽

Deficient Mice

Progranulin (PGRN) is a widely expressed protein involved in diverse biological processes. Haploinsufficiency of PGRN in the human causes tau-negative, ubiquitin-positive frontotemporal dementia (FTD). However, the mechanisms are unknown. To explore the role of PGRN in vivo, we generated PGRN-deficient mice. Macrophages from these mice released less interleukin-10 and more inflammatory cytokines than wild type (WT) when exposed to bacterial lipopolysaccharide. PGRN-deficient mice failed to clear Listeria monocytogenes infection as quickly as WT and allowed bacteria to proliferate in the brain, with correspondingly greater inflammation than in WT. PGRN-deficient macrophages and microglia were cytotoxic to hippocampal cells in vitro, and PGRN-deficient hippocampal slices were hypersusceptible to deprivation of oxygen and glucose. With age, brains of PGRN-deficient mice displayed greater activation of microglia and astrocytes than WT, and their hippocampal and thalamic neurons accumulated cytosolic phosphorylated transactivation response element DNA binding protein–43. Thus, PGRN is a key regulator of inflammation and plays critical roles in both host defense and neuronal integrity. FTD associated with PGRN insufficiency may result from many years of reduced neutrotrophic support together with cumulative damage in association with dysregulated inflammation.

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