Ultrasonic cerebrospinal fluid clearance improves outcomes in hemorrhagic brain injury models
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PROVIDER: PRJNA1260238 | ENA |
REPOSITORIES: ENA
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Project description:Impaired clearance of the byproducts of neurologic injury exacerbates disease progression and severity. We have developed a noninvasive, low intensity transcranial focused ultrasound protocol that facilitates removal of pathogenic substances from the cerebrospinal fluid (CSF) and brain interstitium. This protocol clears blood products from the central nervous system in two mouse models of hemorrhagic brain injury. Cleared blood products accumulate in the cervical lymph nodes from both the CSF and interstitial compartments, indicating clearance through meningeal lymphatics. Treatment with this ultrasound protocol reduced neuroinflammation and neurocytotoxicity, improved behavioral outcomes, decreased morbidity and, importantly, increased survival. Clearance efficacy was independent of thermal effects, given the lack of significant heating noted by simulation and experimental verification. Instead, protocol application was associated with a shift of microglial polarization to a homeostatic state and an increase of astrocytic endfeet aquaporin-4 polarization. As these processes are thought to be downstream of mechanosensitive channels, we confirmed that blockade of mechanosensitive channels blocks clearance and that the protocol was effective when applied in anesthetized subjects. This indicates that ultrasound acts as a non-pharmacologic agonist of mechanosensitive channels to induce these homeostatic immune and glymphatic effects, in a way that does not depend on sensory stimulation or a specific neural activity pattern. Notably, the low intensity of this protocol is within FDA guidelines for safe ultrasound application, making it readily clinically translatable. Overall, our results demonstrate that this low-intensity transcranial focused ultrasound protocol induces cellular processes that clear hemorrhagic products from the brain via the meningeal lymphatic system, offering a novel therapeutic tool for the clearance of other neurotoxic byproducts in varied neurologic disorders.
2025-09-08 | GSE296613 | GEO
Project description:During demyelination myeloid cells remove myelin debris and promote remyelination. Dysfunctional myeloid cells are associated with peroxisomal leukodystrophies, yet the role of peroxisomes in myeloid cells responding to demyelination remains unknown. The impact of dysfunctional peroxisomes in demyelination-responding myeloid cells was interrogated in Abcd1 and Pex5 knockout mice using the cuprizone model for myelin damage. Abcd1 loss did not affect the demyelination response in myeloid cells, however, Pex5 deficiency impaired remyelination and significantly undermined myelin debris clearance. Molecular analysis in Pex5 depleted macrophages revealed repressed APOE activity and attenuated expression of the sterol exporter pathway integral to myelin debris metabolism, which was associated with an aggravated foamy macrophage phenotype in myelin engulfing myeloid cells. In summary, we report a critical contribution of peroxisomes to myelin debris clearance, myelin lipid processing, and pro-remyelinating properties in myeloid cells.
2025-11-13 | GSE272138 | GEO
Project description:A subset of infants and adults with hemorrhagic stroke and intraventricular hemorrhage (IVH) ultimately develop a life-threatening accumulation of cerebrospinal fluid (CSF), termed post-hemorrhagic hydrocephalus (PHH). An incomplete understanding of this variably progressive condition has hampered the development of new therapies beyond serial neurosurgical interventions. We describe an adeno-associated viral (AAV) gene augmentation approach leveraging the Na-K-Cl cotransporter, NKCC1, to enhance a choroid plexus (ChP) mechanism of CSF surveillance, potassium homeostasis, and water movement to drive decreases in ventricle size in embryonic, neonatal, and adult mouse models of IVH. Intraventricular blood led to increased CSF [K+], triggered cytosolic calcium in ChP epithelial cells, and was followed by NKCC1 activation. ChP-targeted AAV-NKCC1 rapidly reversed blood-induced ventriculomegaly and led to persistently increased CSF clearance capacity, validating the model and treating the most salient clinical features of PHH. NKCC1 is a bi-directional cotransporter, and these data demonstrate that NKCC1 activation triggered a trans-choroidal, NKCC1-dependent CSF ion/water clearance out of the ventricle. Inactive, phosphodeficient AAV-NKCC1-NT51 failed to mitigate ventriculomegaly, indicating that the beneficial effects of NKCC1 augmentation required both elevated CSF [K+] and upstream activation via phosphorylation. Excessive CSF [K+] fluctuations correlated with permanent shunting outcome in humans following hemorrhagic stroke, suggesting potential therapeutic benefits. Collectively, these data highlight a novel role for the ChP in rapid compensation for alterations in CSF homeostasis following IVH and demonstrate the utility of targeted gene therapy to mitigate intracranial fluid accumulation following hemorrhage.
2024-05-24 | PXD039738 | Pride
Project description:Peroxisomal integrity in myeloid cells is required for myelin debris clearance and remyelination
| PRJNA1135185 | ENA
Project description:Phagocytosis of synaptic debris by microglia is critical for CNS development and homeostasis. Less well understood are microglial functions in injured adult brain, where their presumed role is clearance of neuronal debris. Assay of this process is challenging, because the resulting peripheral myeloid-cell engraftment is difficult to dissociate from microglial clearance. The model used here, optic nerve crush injury in adult mouse, stimulates rapid engulfment of synaptic material by microglia residing in the lateral geniculate nucleus (LGN), sufficiently distant from the injury to preclude peripheral-cell engraftment. Pre-injury pharmacological depletion of microglia causes post-injury accumulation of synaptic debris, suggesting that these, not astrocytes, are the dominant post-injury phagocytes. Genetic and pharmacological manipulations revealed that neuronal activity, which regulates microglial engulfment of synaptic debris in development, does not do so in post-injury synaptic material clearance in adulthood, where such clearance depends instead on axonal integrity. RNAseq reveals C1q involvement in clearance of debris by LGN-resident microglia, supporting our finding of its impaired clearance in C1qa-/- and Itgam-/- mice. Our results demonstrate how neurodegenerative debris is cleared by microglial phagocytosis, and offer a model for assaying microglial phagocytic activity and studying its mechanisms and physiological roles.
2018-06-07 | GSE107635 | GEO
Project description:Activating microbubbles (MBs) with focused ultrasound (FUS) for blood-brain (BBB) and blood-tumor barrier (BTB) opening permits targeted therapeutic delivery. While the effects of FUS-mediated BBB opening have been investigated for normal brain tissue, no such studies exist for intracranial tumors. As this technology advances into clinical immunotherapy trials, it will be crucial to understand how FUS modulates the tumor immune microenvironment. Here, bulk RNA sequencing revealed that FUS BTB/BBB opening (1 MHz, 0.5 MPa peak-negative pressure) of intracranial B16F1cOVA tumors increases the expression of genes related to proinflammatory cytokine and chemokine signaling, pattern recognition receptor signaling, and antigen processing and presentation. Flow cytometry revealed increased maturation (i.e. CD86) of dendritic cells (DCs) in the meninges and altered antigen loading of DCs in both the tumor and meninges. For DCs in tumor draining lymph nodes, FUS had no effect on maturation and elicited only a trend towards increased presentation of tumor-derived peptide by MHC. Neither tumor endothelial cell adhesion molecule expression nor homing of activated T cells was affected by FUS. In conclusion, FUS-mediated BTB/BBB opening elicits signatures of inflammation; however, the response is mild, transient, and unlikely to elicit a systemic response independent of administration of immune adjuvants.
2020-06-10 | GSE152138 | GEO
Project description:A prevalent view in treating age-dependent disorders including Alzheimer’s disease (AD) is that the underlying amyloid plaque pathology must be targeted for cognitive improvements. In contrast, we report here that repeated scanning ultrasound (SUS) treatment at 1 MHz frequency can ameliorate memory deficits in the APP23 mouse model of AD without reducing amyloid-β (Aβ) burden. Different from previous studies that had shown Aβ clearance as a consequence of blood-brain barrier (BBB) opening, here, the BBB was not opened as no microbubbles were used. Quantitative proteomics and functional magnetic resonance imaging revealed that ultrasound induced long-lasting functional changes that correlate with the improvement in memory. Intriguingly, the treatment was more effective at a higher frequency (1MHz) than at a frequency within the range currently explored in clinical trials in AD patients (286 kHz). Together, our data suggest frequency-dependent bio-effects of ultrasound and a dissociation of cognitive improvement and Aβ clearance, with important implications for the design of trials for AD therapies.
2024-03-19 | PXD050248 | Pride
Project description:The human placenta is covered by a single multinucleated fetal cell, the syncytiotrophoblast, which is bathed in maternal blood. During all pregnancies, membrane enclosed extracellular vesicles derived from the syncytiotrophoblast are extruded into the maternal blood.The large size of these extracellular vesicles (diameter larger than 10µm) is referred to as trophoblastic debris in this study. We have shown in the past that endothleial cells are involved in clearence of this trophoblastic debris and induction of immune tolerence by trophoblastic debris.This study aimed to characterise the transcriptional changes that occur in human vascular endothelial cells following exposure to trophoblastic debris from normal first trimester placentae. Microarrays were used to probe transcriptomic changes 2 and 21 hours after exposure of endothelial cells (Human microvascular endothelial cell line,HMEC-1) to trophoblastic debris from normal first trimester placentae Trophoblastic debris were isolated by low speed centrifugation from three individual first trimester human placentae (three biological replicates). The protein content in trophoblastic debris was measured by BCA assay. HMEC-1 was co-cultured with trophoblastic debris (60ug/ml total debris protein contents) for either 2 or 21 hours before RNA extraction. Untreated HMEC-1 at 2 and 21 hours were used as controls.In total, 12 samples were analyzed.
2016-08-21 | E-GEOD-69996 | biostudies-arrayexpress
Project description:The efficiency of central nervous system (CNS) remyelination declines with age. This is in part due to an age-associated decline in the phagocytic removal of myelin debris, which contains inhibitors of oligodendrocyte progenitor cell differentiation. In this study we show that expression of genes involved in the retinoid X receptor (RXR) pathway are decreased with aging in myelin-phagocytosing cells. Loss of RXR function in young macrophages mimics aging by delaying remyelination after experimentally-induced demyelination, while RXR agonists partially restore myelin debris phagocytosis in aged macrophages. The FDA-approved RXR agonist bexarotene, when used in concentrations achievable in human subjects, caused a reversion of the gene expression profile in aging human monocytes to a more youthful profile. These results reveal the RXR pathway as a positive regulator of myelin debris clearance and a key player in the age-related decline in remyelination that may be targeted by available or newly-developed therapeutics. 24 Human CD14+ monocyte-sorted PBMC samples representing 4 Healthy Volunteers (HV) and 4 Multiple Sclerosis (MS) patients under 3 different treatment conditions. Condition 1 = (-) Phagocystosis (-) Bexarotene. Condition 2 = (+) Phagocystosis (-) Bexarotene. Condition 3 = (+) Phagocystosis (+) Bexarotene.
2015-11-04 | E-GEOD-66988 | biostudies-arrayexpress
Project description:Gene expression information is useful in prioritizing candidate genes in linkage intervals. The data can also identify pathways involved in the pathophysiology of disease. We used microarrays to identify which genes are expressed in either intracranial arteries (control) or in intracranial aneurysms (case), and can therefore contribute to the disease phenotypes. We used microarrays to identify the pathway membership of expressed genes and the overrepresentation of pathways with expressed genes in the known linkage intervals for intracranial aneurysms. Keywords: Characterization of expression in both diseased and non-diseased intracranial arteries.
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