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Doleschall, B.

Publications and source records attributed to Doleschall, B..

5 recordsLinked to original sources

Connectomics by Sequencing Reveals Self-Organizing Principles of Neuronal Networks in Cerebral Organoids

Functional neural networks emerge as developing neurons form synaptic connections. Revealing how these connections are organized and perturbed in disease requires linking single-neuron connectivity to molecular state across thousands of networks, which is challenging with current methods. We developed COSCO (Connectomics by Sequencing in Cerebral Organoids), combining barcoded monosynaptic rabies tracing with single-cell RNA sequencing to reconstruct over 10,000 networks across organoids. We demonstrate that organoid circuitry self-organizes into stereotyped network motifs governed by cell-intrinsic wiring rules aligning with features of mouse cortical connectivity. Projecting network topology onto transcriptomic space reveals that wiring correlates with cell-adhesion and synaptic gene expression programs. In a Tuberous Sclerosis Complex model, pathological hyperexcitability coincides with topological rewiring: mutant networks become more heterogeneous, driven by the transcriptional distribution of upper layer excitatory cell states. This work establishes cerebral organoids as a model to study self-organization of human connectivity, and its disruption in neurodevelopmental disease. O_FIG O_LINKSMALLFIG WIDTH=199 HEIGHT=200 SRC="FIGDIR/small/755792v1_ufig1.gif" ALT="Figure 1"> View larger version (66K): org.highwire.dtl.DTLVardef@50ade8org.highwire.dtl.DTLVardef@c97320org.highwire.dtl.DTLVardef@1a53a47org.highwire.dtl.DTLVardef@9520ad_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

ARID1B controls transcriptional programs of axon projection in the human corpus callosum

Mutations in ARID1B, a member of the mSWI/SNF complex, cause severe neurodevelopmental phenotypes with elusive mechanisms in humans. The most common structural abnormality in the brain of ARID1B patients is agenesis of the corpus callosum (ACC). This condition is characterized by a partial or complete absence of the corpus callosum (CC), an interhemispheric white matter tract that connects distant cortical regions. Using human neural organoids, we identify a vulnerability of callosal projection neurons (CPNs) to ARID1B haploinsufficiency, resulting in abnormal maturation trajectories and dysregulation of transcriptional programs of CC development. Through a novel in vitro model of the CC tract, we demonstrate that ARID1B mutations reduce the proportion of CPNs capable of forming long-range projections, leading to structural underconnectivity phenotypes. Our study uncovers new functions of the mSWI/SNF during human corticogenesis, identifying cell-autonomous defects in axonogenesis as a cause of ACC in ARID1B patients. O_FIG O_LINKSMALLFIG WIDTH=193 HEIGHT=200 SRC="FIGDIR/small/539362v1_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@dd4e9aorg.highwire.dtl.DTLVardef@153a081org.highwire.dtl.DTLVardef@14e884corg.highwire.dtl.DTLVardef@d64081_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstractC_FLOATNO Human callosal projection neurons are vulnerable to ARID1B haploinsufficiency. (Top) During healthy development, callosal projection neurons (CPNs) project long interhemispheric axons, forming the corpus callosum (CC) tract, which can be modeled in vitro. (Bottom) In ARID1B patients, transcriptional dysregulation of genetic programs of CC development reduces the formation of long-range projections from CPNs, causing CC agenesis in vivo and underconnectivity phenotypes in vitro. C_FIG

neuroscience↗

Intra-articular AAV-PHP.S mediated chemogenetic targeting of knee-innervating DRG neurons alleviates inflammatory pain in mice

ObjectiveJoint pain is the major clinical symptom of arthritis that affects millions of people. Controlling the excitability of knee-innervating dorsal root ganglion (DRG) neurons (knee neurons) could potentially provide pain relief. Therefore, our objective was to evaluate whether the newly engineered adeno-associated virus (AAV) serotype, AAV-PHP.S, can deliver functional artificial receptors to control knee neuron excitability following intra-articular knee injection. MethodsAAV-PHP.S virus packaged with dTomato fluorescent protein and either excitatory (Gq) or inhibitory (Gi) designer receptors activated by designer drugs (DREADDs) was injected into the knee joint of adult mice. Labelling of DRG neurons by AAV-PHP.S from the knee was evaluated using immunohistochemistry. Functionality of Gq- and Gi-DREADDs was evaluated using whole-cell patch clamp electrophysiology on acutely cultured DRG neurons. Pain behavior in mice was assessed using a digging assay, dynamic weight bearing and rotarod, before and after intra-peritoneal administration of the DREADD activator, Compound 21. ResultsWe show that AAV-PHP.S can deliver functional genes into the DRG neurons when injected into the knee joint in a similar manner to the well-established retrograde tracer, fast blue. Short-term activation of AAV-PHP.S delivered Gq-DREADD increases excitability of knee neurons in vitro, without inducing overt pain in mice when activated in vivo. By contrast, in vivo Gi-DREADD activation alleviated complete Freunds adjuvant mediated knee inflammation-induced deficits in digging behavior, with a concomitant decrease in knee neuron excitability observed in vitro. ConclusionsWe describe an AAV-mediated chemogenetic approach to specifically control joint pain, which may be utilized in translational arthritic pain research.

neuroscience↗

Identification of a novel population of peripheral sensory neuron that regulates blood pressure

The vasculature is innervated by a network of peripheral afferents that sense and regulate blood flow. Here, we describe a system of non-peptidergic sensory neurons with cell bodies in the spinal ganglia that regulate vascular tone in the distal arteries. We identify a population of mechanosensitive neurons marked by TrkC and Tyrosine hydroxylase in the dorsal root ganglia that project to blood vessels. Local stimulation of these neurons decreases vessel diameter and blood flow, while systemic activation increases systolic blood pressure and heart rate variability via the sympathetic nervous system. Chemogenetic inactivation or ablation of the neurons provokes variability in local blood flow leading to a reduction in systolic blood pressure, increased heart rate variability and ultimately lethality within 48 hours. Thus, TrkC/Tyrosine hydroxylase positive sensory neurons form part of a sensory feedback mechanism that maintains cardiovascular homeostasis through the autonomic nervous system.

neuroscience↗

NGF-mediated photoablation of nociceptors reduces pain behavior in mice

Nerve growth factor (NGF) and its receptors TrkA and p75 play a key role in the development and function of peripheral nociceptive neurons. Here we describe novel technology to selectively photoablate TrkA positive nociceptors through delivery of a phototoxic agent coupled to an engineered NGF ligand and subsequent near infrared (NIR) illumination. We demonstrate that this approach allows for on demand and localized reversal of pain behaviors in mouse models of acute, inflammatory, neuropathic and joint pain. To target peripheral nociceptors we generated a SNAP-tagged NGF derivative, NGFR121W that binds to TrkA/p75 receptors but does not provoke signaling in TrkA positive cells or elicit pain behaviors in mice. NGFR121W-SNAP was coupled to the photosensitizer IRDye(R)700DX phthalocyanine (IR700) and injected subcutaneously. Following NIR illumination of the injected area, behavioral responses to nociceptive mechanical and sustained thermal stimuli, but not innocuous stimuli, were substantially reduced. Similarly, in models of inflammatory, osteoarthritic and neuropathic pain, mechanical hypersensitivity was abolished for three weeks following a single treatment regime. We demonstrate that this loss of pain behavior coincides with the retraction of neurons from the skin which then re-innervate the epidermis after 3 weeks corresponding with the return of mechanical hypersensitivity. Thus NGFR121W-SNAP-mediated photoablation is a minimally invasive approach to reversibly silence nociceptor input from the periphery, and control pain and hypersensitivity to mechanical stimuli.

neuroscience↗