scholarly journals Novel tool to quantify with single-cell resolution the number of incoming AAV genomes co-expressed in the mouse nervous system

Gene Therapy ◽  
2021 ◽  
Author(s):  
Carola J. Maturana ◽  
Jessica L. Verpeut ◽  
Mahdi Kooshkbaghi ◽  
Esteban A. Engel

AbstractAdeno-associated viral (AAV) vectors are an established and safe gene delivery tool to target the nervous system. However, the payload capacity of <4.9 kb limits the transfer of large or multiple genes. Oversized payloads could be delivered by fragmenting the transgenes into separate AAV capsids that are then mixed. This strategy could increase the AAV cargo capacity to treat monogenic, polygenic diseases and comorbidities only if controlled co-expression of multiple AAV capsids is achieved on each transduced cell. We developed a tool to quantify the number of incoming AAV genomes that are co-expressed in the nervous system with single-cell resolution. By using an isogenic mix of three AAVs each expressing single fluorescent reporters, we determined that expression of much greater than 31 AAV genomes per neuron in vitro and 20 genomes per neuron in vivo is obtained across different brain regions including anterior cingulate, prefrontal, somatomotor and somatosensory cortex areas, and cerebellar lobule VI. Our results demonstrate that multiple AAV vectors containing different transgenes or transgene fragments, can efficiently co-express in the same neuron. This tool can be used to design and improve AAV-based interrogation of neuronal circuits, map brain connectivity, and treat genetic diseases affecting the nervous system.

Science ◽  
2021 ◽  
Vol 372 (6540) ◽  
pp. eabf1230 ◽  
Author(s):  
Iain C. Clark ◽  
Cristina Gutiérrez-Vázquez ◽  
Michael A. Wheeler ◽  
Zhaorong Li ◽  
Veit Rothhammer ◽  
...  

Cell-cell interactions control the physiology and pathology of the central nervous system (CNS). To study astrocyte cell interactions in vivo, we developed rabies barcode interaction detection followed by sequencing (RABID-seq), which combines barcoded viral tracing and single-cell RNA sequencing (scRNA-seq). Using RABID-seq, we identified axon guidance molecules as candidate mediators of microglia-astrocyte interactions that promote CNS pathology in experimental autoimmune encephalomyelitis (EAE) and, potentially, multiple sclerosis (MS). In vivo cell-specific genetic perturbation EAE studies, in vitro systems, and the analysis of MS scRNA-seq datasets and CNS tissue established that Sema4D and Ephrin-B3 expressed in microglia control astrocyte responses via PlexinB2 and EphB3, respectively. Furthermore, a CNS-penetrant EphB3 inhibitor suppressed astrocyte and microglia proinflammatory responses and ameliorated EAE. In summary, RABID-seq identified microglia-astrocyte interactions and candidate therapeutic targets.


Endocrinology ◽  
2007 ◽  
Vol 148 (12) ◽  
pp. 5865-5873 ◽  
Author(s):  
Xing-Li Meng ◽  
Owen M. Rennert ◽  
Wai-Yee Chan

Human chorionic gonadotropin (hCG) and LH play an important role in reproductive physiology. Both hCG and LH bind to the same LH/choriogonadotropin receptor (LH/CG-R). Recent reports documented the temporal and spatial expression of LH/CG-R in the developing and mature mammalian brain. Administration of hCG promoted nerve regeneration in vivo and neurite outgrowth and survival of primary neurons in vitro. The function of hCG/LH and LH/CG-R in the nervous system remains unclear. In this study, we report that hCG/LH induced distinct morphological and biochemical changes, characteristic of neuronal differentiation, in PC12 cells stably expressing LH/CG-R and that the differentiation effect is ligand dose and time dependent. Western blot analysis revealed that both the ERKs and p38 MAPK are activated after hCG treatment. Inhibitor studies showed both the ERK and p38 MAPK signal transduction pathways are required for this differentiation process, which is cAMP dependent and protein kinase A independent. These findings imply a potential role for hCG/LH and LH/CG-R in the development, maintenance, and regeneration of the mammalian nervous system, and in the neuropathogenesis of genetic diseases caused by a mutated LH/CG-R.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
David S. Fischer ◽  
Meshal Ansari ◽  
Karolin I. Wagner ◽  
Sebastian Jarosch ◽  
Yiqi Huang ◽  
...  

AbstractThe in vivo phenotypic profile of T cells reactive to severe acute respiratory syndrome (SARS)-CoV-2 antigens remains poorly understood. Conventional methods to detect antigen-reactive T cells require in vitro antigenic re-stimulation or highly individualized peptide-human leukocyte antigen (pHLA) multimers. Here, we use single-cell RNA sequencing to identify and profile SARS-CoV-2-reactive T cells from Coronavirus Disease 2019 (COVID-19) patients. To do so, we induce transcriptional shifts by antigenic stimulation in vitro and take advantage of natural T cell receptor (TCR) sequences of clonally expanded T cells as barcodes for ‘reverse phenotyping’. This allows identification of SARS-CoV-2-reactive TCRs and reveals phenotypic effects introduced by antigen-specific stimulation. We characterize transcriptional signatures of currently and previously activated SARS-CoV-2-reactive T cells, and show correspondence with phenotypes of T cells from the respiratory tract of patients with severe disease in the presence or absence of virus in independent cohorts. Reverse phenotyping is a powerful tool to provide an integrated insight into cellular states of SARS-CoV-2-reactive T cells across tissues and activation states.


1997 ◽  
Vol 77 (5) ◽  
pp. 2427-2445 ◽  
Author(s):  
Heath S. Lukatch ◽  
M. Bruce Maciver

Lukatch, Heath S. and M. Bruce MacIver. Physiology, pharmacology, and topography of cholinergic neocortical oscillations in vitro. J. Neurophysiol. 77: 2427–2445, 1997. Rat neocortical brain slices generated rhythmic extracellular field [microelectroencephalogram (micro-EEG)] oscillations at theta frequencies (3–12 Hz) when exposed to pharmacological conditions that mimicked endogenous ascending cholinergic and GABAergic inputs. Use of the specific receptor agonist and antagonist carbachol and bicuculline revealed that simultaneous muscarinic receptor activation and γ-aminobutyric acid-A (GABAA)-mediated disinhibition werenecessary to elicit neocortical oscillations. Rhythmic activity was independent of GABAB receptor activation, but required intact glutamatergic transmission, evidenced by blockade or disruption of oscillations by 6-cyano-7-nitroquinoxaline-2,3-dione and (±)-2-amino-5-phosphonovaleric acid, respectively. Multisite mapping studies showed that oscillations were localized to areas 29d and 18b (Oc2MM) and parts of areas 18a and 17. Peak oscillation amplitudes occurred in layer 2/3, and phase reversals were observed in layers 1 and 5. Current source density analysis revealed large-amplitude current sinks and sources in layers 2/3 and 5, respectively. An initial shift in peak inward current density from layer 1 to layer 2/3 indicated that two processes underlie an initial depolarization followed by oscillatory activity. Laminar transections localized oscillation-generating circuitry to superficial cortical layers and sharp-spike-generating circuitry to deep cortical layers. Whole cell recordings identified three distinct cell types based on response properties during rhythmic micro-EEG activity: oscillation-on (theta-on) and -off (theta-off) neurons, and transiently depolarizing glial cells. Theta-on neurons displayed membrane potential oscillations that increased in amplitude with hyperpolarization (from −30 to −90 mV). This, taken together with a glutamate antagonist-induced depression of rhythmic micro-EEG activity, indicated that cholinergically driven neocortical oscillations require excitatory synaptic transmission. We conclude that under the appropriate pharmacological conditions, neocortical brain slices were capable of producing localized theta frequency oscillations. Experiments examining oscillation physiology, pharmacology, and topography demonstrated that neocortical brain slice oscillations share many similarities with the in vivo and in vitro theta EEG activity recorded in other brain regions.


1946 ◽  
Vol 84 (4) ◽  
pp. 277-292 ◽  
Author(s):  
S. Edward Sulkin ◽  
Christine Zarafonetis ◽  
Andres Goth

Anesthesia with diethyl ether significantly alters the course and outcome of experimental infections with the equine encephalomyelitis virus (Eastern or Western type) or with the St. Louis encephalitis virus. No comparable effect is observed in experimental infections produced with rabies or poliomyelitis (Lansing) viruses. The neurotropic virus infections altered by ether anesthesia are those caused by viruses which are destroyed in vitro by this anesthetic, and those infections not affected by ether anesthesia are caused by viruses which apparently are not destroyed by ether in vitro. Another striking difference between these two groups of viruses is their pathogenesis in the animal host; those which are inhibited in vivo by ether anesthesia tend to infect cells of the cortex, basal ganglia, and only occasionally the cervical region of the cord. On the other hand, those which are not inhibited in vivo by ether anesthesia tend to involve cells of the lower central nervous system and in the case of rabies, peripheral nerves. This difference is of considerable importance in view of the fact that anesthetics affect cells of the lower central nervous system only in very high concentrations. It is obvious from the complexity of the problem that no clear-cut statement can be made at this point as to the mechanism of the observed effect of ether anesthesia in reducing the mortality rate in certain of the experimental neurotropic virus infections. Important possibilities include a direct specific effect of diethyl ether upon the virus and a less direct effect of the anesthetic upon the virus through its alteration of the metabolism of the host cell.


2000 ◽  
Vol 164 (6) ◽  
pp. 3047-3055 ◽  
Author(s):  
Dragana Jankovic ◽  
Marika C. Kullberg ◽  
Nancy Noben-Trauth ◽  
Patricia Caspar ◽  
William E. Paul ◽  
...  

2016 ◽  
Vol 38 (3) ◽  
pp. 859-870 ◽  
Author(s):  
Mingfeng He ◽  
Hongquan Dong ◽  
Yahui Huang ◽  
Shunmei Lu ◽  
Shu Zhang ◽  
...  

Background/Aims: Microglia are an essential player in central nervous system inflammation. Recent studies have demonstrated that the astrocytic chemokine, CCL2, is associated with microglial activation in vivo. However, CCL2-induced microglial activation has not yet been studied in vitro. The purpose of the current study was to understand the role of astrocyte-derived CCL2 in microglial activation and to elucidate the underlying mechanism(s). Methods: Primary astrocytes were pre-treated with CCL2 siRNA and stimulated with TNF-α. The culture medium (CM) was collected and added to cultures of microglia, which were incubated with and without CCR2 inhibitor. Microglial cells were analyzed by quantitative RT-PCR to determine whether they polarized to the M1 or M2 state. Microglial migratory ability was assessed by transwell migration assay. Results: TNF-α stimulated the release of CCL2 from astrocytes, even if the culture media containing TNF-α was replaced with fresh media after 3 h. CM from TNF-α-stimulated astrocytes successfully induced microglial activation, which was ascertained by increased activation of M1 and enhanced migration ability. In contrast, CM from astrocytes pretreated with CCL2 siRNA showed no effect on microglial activation, compared to controls. Additionally, microglia pre-treated with RS102895, a CCR2 inhibitor, were resistant to activation by CM from TNF-α-stimulated astrocytes. Conclusion: This study demonstrates that the CCL2/CCR2 pathway of astrocyte-induced microglial activation is associated with M1 polarization and enhanced migration ability, indicating that this pathway could be a useful target to ameliorate inflammation in the central nervous system.


2002 ◽  
Vol 13 (2) ◽  
pp. 698-710 ◽  
Author(s):  
Sylvie Ozon ◽  
Antoine Guichet ◽  
Olivier Gavet ◽  
Siegfried Roth ◽  
André Sobel

Stathmin is a ubiquitous regulatory phosphoprotein, the generic element of a family of neural phosphoproteins in vertebrates that possess the capacity to bind tubulin and interfere with microtubule dynamics. Although stathmin and the other proteins of the family have been associated with numerous cell regulations, their biological roles remain elusive, as in particular inactivation of the stathmin gene in the mouse resulted in no clear deleterious phenotype. We identified stathmin phosphoproteins inDrosophila, encoded by a unique gene sharing the intron/exon structure of the vertebrate stathmin andstathmin family genes. They interfere with microtubule assembly in vitro, and in vivo when expressed in HeLa cells. Drosophila stathmin expression is regulated during embryogenesis: it is high in the migrating germ cells and in the central and peripheral nervous systems, a pattern resembling that of mammalian stathmin. Furthermore, RNA interference inactivation ofDrosophila stathmin expression resulted in germ cell migration arrest at stage 14. It also induced important anomalies in nervous system development, such as loss of commissures and longitudinal connectives in the ventral cord, or abnormal chordotonal neuron organization. In conclusion, a single Drosophilagene encodes phosphoproteins homologous to the entire vertebrate stathmin family. We demonstrate for the first time their direct involvement in major biological processes such as development of the reproductive and nervous systems.


1991 ◽  
Vol 331 (1261) ◽  
pp. 259-262

In the developing vertebrate nervous system the survival of neurons becomes dependent on the supply of a neurotrophic factor from their targets when their axons reach these targets. To determine how the onset of neurotrophic factor dependency is coordinated with the arrival of axons in the target field, we have studied the growth and survival of four populations of cranial sensory neurons whose axons have markedly different distances to grow to reach their targets. Axonal growth rate both in vivo and in vitro is related to target distance; neurons with more distant targets grow faster. The onset trophic factor dependency in culture is also related to target distance; neurons with more distant targets survive longer before becoming trophic factor dependent. These data suggest that programmes of growth and survival in early neurons play an important role in coordinating the timing of trophic interactions in the developing nervous system.


2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi5-vi5
Author(s):  
Robert Suter ◽  
Vasileios Stathias ◽  
Anna Jermakowicz ◽  
Hari Pradhyumnan ◽  
Maurizio Affer ◽  
...  

Abstract Glioblastoma (GBM) remains the most common adult brain cancer, with a dismal average patient survival of less than two years. No new treatments have been approved for GBM since the introduction of the alkylating agent temozolomide in 2005. Even then, temozolomide treatment only increases the average survival of GBM patients by a few months. Thus, novel therapeutic options are direly needed. The aurora kinases A and B are targetable and overexpressed in GBM, and their expression is highly correlated with patient survival outcomes. Our lab has found that small molecule aurora kinase inhibition reduces GBM tumor growth in vitro and in vivo, however, eventually tumors still grow. Computational analysis integrating compound transcriptional response signatures from the LINCS L1000 dataset with the single-cell RNA-sequencing data of patient GBM tumors resected at the University of Miami predicts that aurora inhibition targets a subset of cells present within any GBM tumor. Results of in vivo single-cell perturbation experiments with the aurora kinase inhibitor alisertib coincide with our predictions and reveal a cellular transcriptional phenotype resistant to aurora kinase inhibition, characterized by a mesenchymal expression program. We find that small molecules that are predicted to target different cell populations from alisertib, including this resistant mesenchymal population, synergize with alisertib to kill GBM cells. As a whole, we have identified the cellular population resistant to aurora kinase inhibition and have developed an analytical framework that identifies synergistic small molecule combinations by identifying compounds that target transcriptionally distinct cellular populations within GBM tumors.


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