scholarly journals Parkin deficiency perturbs striatal circuit dynamics

2019 ◽  
Author(s):  
Magdalena K. Baaske ◽  
Edgar R. Kramer ◽  
Durga Praveen Meka ◽  
Gerhard Engler ◽  
Andreas K. Engel ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Mutant Mice ◽  
Projection Neurons ◽  
Activity Levels ◽  
Loss Of Function ◽  
Beta Oscillations ◽  
Field Coupling ◽  
Cell Type Specific ◽  
Elevated Activity ◽  
Fast Spiking

AbstractLoss-of-function mutations in the parkin-encoding PARK2 gene cause young-onset, autosomal recessive Parkinson’s disease (PD). Here, we investigated how parkin mutations affect cortico-basal ganglia circuit dynamics and cell-type-specific functional connectivity by recording simultaneously from motor cortex, striatum and globus pallidus (GP) in anesthetized parkin-mutant mice.While ongoing activity of presumed striatal spiny projection neurons and their downstream counterparts in the GP was not different from controls, parkin deficiency had a differential impact on striatal interneurons: In parkin-mutant mice, tonically active neurons displayed elevated activity levels. Baseline firing of transgenic striatal fast spiking interneurons (FSI), on the contrary, was reduced and the correlational structure of the FSI microcircuitry was disrupted. The entire transgenic striatal microcircuit showed enhanced and phase-shifted phase coupling to slow (1-3Hz) cortical population oscillations. Unexpectedly, local field potentials recorded from striatum and GP of parkin-mutant mice robustly displayed amplified beta oscillations (∼22Hz), phase-coupled to cortex. Moreover, parkin deficiency selectively increased spike-field coupling of FSIs to beta oscillations.Our findings suggest that loss of parkin function leads to amplifications of synchronized cortico-striatal oscillations and intrastriatal reconfiguration of interneuronal circuits. This presymptomatic disarrangement of dynamic functional connectivity may precede nigro-striatal neurodegeneration and predispose to imbalance of striatal outflow accompanying symptomatic PD.

scholarly journals “Modulation of apoptosis controls inhibitory interneuron number in the cortex”

2017 ◽  
Author(s):  
Myrto Denaxa ◽  
Guilherme Neves ◽  
Adam Rabinowitz ◽  
Sarah Kemlo ◽  
Petros Liodis ◽  
...  
Keyword(s):  
Physiological State ◽  
Inhibitory Interneuron ◽  
Projection Neurons ◽  
Activity Levels ◽  
Cortical Interneurons ◽  
A Cell ◽  
Cell Type Specific ◽  
Excitatory Projection ◽  
Cortical Excitation ◽  
The Right

AbstractCortical networks are composed of excitatory projection neurons and inhibitory interneurons. Finding the right balance between the two is important for controlling overall cortical excitation and network dynamics. However, it is unclear how the correct number of cortical interneurons (CIs) is established in the mammalian forebrain. CIs are generated in excess from basal forebrain progenitors and their final numbers are adjusted via an intrinsically determined program of apoptosis that takes place during an early postnatal window. Here, we provide evidence that the extent of CI apoptosis during this critical period is plastic, cell type specific and can be reduced in a cell autonomous manner by acute increases in neuronal activity. We propose that the physiological state of the emerging neural network controls the activity levels of local CIs to modulate their numbers in a homeostatic manner.

scholarly journals Single-cell analysis of Foxp1-driven mechanisms essential for striatal development

2019 ◽  
Author(s):  
Ashley G. Anderson ◽  
Ashwinikumar Kulkarni ◽  
Matthew Harper ◽  
Genevieve Konopka
Keyword(s):  
Single Cell ◽  
Target Genes ◽  
Single Cell Analysis ◽  
Cell Types ◽  
Brain Regions ◽  
Projection Neurons ◽  
Loss Of Function ◽  
Cell Type ◽  
Motor Information ◽  
Cell Type Specific

AbstractThe striatum is a critical forebrain structure for integrating cognitive, sensory, and motor information from diverse brain regions into meaningful behavioral output. However, the transcriptional mechanisms that underlie striatal development and organization at single-cell resolution remain unknown. Here, we show that Foxp1, a transcription factor strongly linked to autism and intellectual disability, regulates organizational features of striatal circuitry in a cell-type-dependent fashion. Using single-cell RNA-sequencing, we examine the cellular diversity of the early postnatal striatum and find that cell-type-specific deletion ofFoxp1in striatal projection neurons alters the cellular composition and neurochemical architecture of the striatum. Importantly, using this approach, we identify the non-cell autonomous effects produced by disruptingFoxp1in one cell-type and the molecular compensation that occurs in other populations. Finally, we identify Foxp1-regulated target genes within distinct cell-types and connect these molecular changes to functional and behavioral deficits relevant to phenotypes described in patients withFOXP1loss-of-function mutations. These data reveal cell-type-specific transcriptional mechanisms underlying distinct features of striatal circuitry and identify Foxp1 as a key regulator of striatal development.

scholarly journals Parallel pathways for sound processing and functional connectivity among layer 5 and 6 auditory corticofugal neurons

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Ross S Williamson ◽  
Daniel B Polley
Keyword(s):  
Functional Connectivity ◽  
Sensory Processing ◽  
Cell Types ◽  
Projection Neurons ◽  
Cortical Projection ◽  
Response Latencies ◽  
Sound Processing ◽  
Downstream Targets ◽  
Sustained Activity ◽  
Fast Spiking

Cortical layers (L) 5 and 6 are populated by intermingled cell-types with distinct inputs and downstream targets. Here, we made optogenetically guided recordings from L5 corticofugal (CF) and L6 corticothalamic (CT) neurons in the auditory cortex of awake mice to discern differences in sensory processing and underlying patterns of functional connectivity. Whereas L5 CF neurons showed broad stimulus selectivity with sluggish response latencies and extended temporal non-linearities, L6 CTs exhibited sparse selectivity and rapid temporal processing. L5 CF spikes lagged behind neighboring units and imposed weak feedforward excitation within the local column. By contrast, L6 CT spikes drove robust and sustained activity, particularly in local fast-spiking interneurons. Our findings underscore a duality among sub-cortical projection neurons, where L5 CF units are canonical broadcast neurons that integrate sensory inputs for transmission to distributed downstream targets, while L6 CT neurons are positioned to regulate thalamocortical response gain and selectivity.

scholarly journals Connectivity characterization of the mouse basolateral amygdalar complex

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Houri Hintiryan ◽  
Ian Bowman ◽  
David L. Johnson ◽  
Laura Korobkova ◽  
Muye Zhu ◽  
...  
Keyword(s):  
Granular Cell ◽  
Cell Types ◽  
Projection Neurons ◽  
Cell Type ◽  
Connectivity Map ◽  
Analysis Techniques ◽  
Domain Specific ◽  
Cell Type Specific ◽  
Unique Domain

AbstractThe basolateral amygdalar complex (BLA) is implicated in behaviors ranging from fear acquisition to addiction. Optogenetic methods have enabled the association of circuit-specific functions to uniquely connected BLA cell types. Thus, a systematic and detailed connectivity profile of BLA projection neurons to inform granular, cell type-specific interrogations is warranted. Here, we apply machine-learning based computational and informatics analysis techniques to the results of circuit-tracing experiments to create a foundational, comprehensive BLA connectivity map. The analyses identify three distinct domains within the anterior BLA (BLAa) that house target-specific projection neurons with distinguishable morphological features. We identify brain-wide targets of projection neurons in the three BLAa domains, as well as in the posterior BLA, ventral BLA, posterior basomedial, and lateral amygdalar nuclei. Inputs to each nucleus also are identified via retrograde tracing. The data suggests that connectionally unique, domain-specific BLAa neurons are associated with distinct behavior networks.

scholarly journals Responsiveness to exogenous cAMP of a Saccharomyces cerevisiae strain conferred by naturally occurring alleles of PDE1 and PDE2.

Genetics ◽  
1993 ◽  
Vol 135 (2) ◽  
pp. 321-326 ◽  
Author(s):  
H Mitsuzawa
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Slow Growth ◽  
Loss Of Function ◽  
Wild Type ◽  
Triple Mutant ◽  
Apparent Absence ◽  
Camp Pathway ◽  
Naturally Occurring ◽  
Elevated Activity ◽  
Growth Phenotype

Abstract The Saccharomyces cerevisiae strain P-28-24C, from which cAMP requiring mutants derived, responded to exogenously added cAMP. Upon the addition of cAMP, this strain showed phenotypes shared by mutants with elevated activity of the cAMP pathway. Genetic analysis involving serial crosses of this strain to a strain with another genetic background revealed that the responsiveness to cAMP results from naturally occurring loss-of-function alleles of PDE1 and PDE2, which encode low and high affinity cAMP phosphodiesterases, respectively. In addition, P-28-24C was found to carry a mutation conferring slow growth that lies in CYR1, which encodes adenylate cyclase, and the slow growth phenotype caused by the cyr1 mutation was suppressed by the pde2 mutation. Therefore P-28-24C is fortuitously a pde1 pde2 cyr1 triple mutant. Responsiveness to cAMP conferred by pde mutations suggests that S. cerevisiae cells are permeable to cAMP to some extent and that the apparent absence of effect of exogenously added cAMP on wild-type cells is due to immediate degradation by cAMP phosphodiesterases.

Genetic analysis of Pycr1 and Pycr2 in mice

Genetics ◽  
2021 ◽  
Author(s):  
Morgane G Stum ◽  
Abigail L D Tadenev ◽  
Kevin L Seburn ◽  
Kathy E Miers ◽  
Pak P Poon ◽  
...  
Keyword(s):  
Neuromuscular Disorders ◽  
Subcutaneous Fat ◽  
Mutant Mice ◽  
Loss Of Function ◽  
Proline Biosynthesis ◽  
Cell Counts ◽  
Chemically Induced ◽  
White Blood Cell Counts ◽  
Redundant Functions ◽  
Altered Lipid

Abstract The final step in proline biosynthesis is catalyzed by three pyrroline-5-carboxylate reductases, PYCR1, PYCR2, and PYCR3, which convert pyrroline-5-carboxylate (P5C) to proline. Mutations in human PYCR1 and ALDH18A1 (P5C Synthetase) cause Cutis Laxa (CL), whereas mutations in PYCR2 cause hypomyelinating leukodystrophy 10 (HLD10). Here, we investigated the genetics of Pycr1 and Pycr2 in mice. A null allele of Pycr1 did not show integument or CL-related phenotypes. We also studied a novel chemically-induced mutation in Pycr2. Mice with recessive loss-of-function mutations in Pycr2 showed phenotypes consistent with neurological and neuromuscular disorders, including weight loss, kyphosis, and hind-limb clasping. The peripheral nervous system was largely unaffected, with only mild axonal atrophy in peripheral nerves. A severe loss of subcutaneous fat in Pycr2 mutant mice is reminiscent of a CL-like phenotype, but primary features such as elastin abnormalities were not observed. Aged Pycr2 mutant mice had reduced white blood cell counts and altered lipid metabolism, suggesting a generalized metabolic disorder. PYCR1 and -2 have similar enzymatic and cellular activities, and consistent with previous studies, both were localized in the mitochondria in fibroblasts. Both PYCR1 and -2 were able to complement the loss of Pro3, the yeast enzyme that converts P5C to proline, confirming their activity as P5C reductases. In mice, Pycr1; Pycr2 double mutants were sub-viable and unhealthy compared to either single mutant, indicating the genes are largely functionally redundant. Proline levels were not reduced, and precursors were not increased in serum from Pycr2 mutant mice or in lysates from skin fibroblast cultures, but placing Pycr2 mutant mice on a proline-free diet worsened the phenotype. Thus, Pycr1 and -2 have redundant functions in proline biosynthesis, and their loss makes proline a semi-essential amino acid. These findings have implications for understanding the genetics of CL and HLD10, and for modeling these disorders in mice.

scholarly journals Periaqueductal efferents to dopamine and GABA neurons of the VTA

2017 ◽  
Author(s):  
Niels R. Ntamati ◽  
Meaghan Creed ◽  
Christian Lüscher
Keyword(s):  
Functional Analysis ◽  
Ventral Tegmental Area ◽  
Periaqueductal Gray ◽  
Retrograde Tracing ◽  
The Other ◽  
Projection Neurons ◽  
Cell Type ◽  
Gaba Neurons ◽  
Other Hand ◽  
Cell Type Specific

AbstractNeurons in the periaqueductal gray (PAG) modulate threat responses and nociception. Activity in the ventral tegmental area (VTA) on the other hand can cause reinforcement and aversion. While in many situations these behaviors are related, the anatomical substrate of a crosstalk between the PAG and VTA remains poorly understood. Here we describe the anatomical and electrophysiological organization of the VTA-projecting PAG neurons. Using rabies-based, cell type-specific retrograde tracing, we observed that PAG to VTA projection neurons are evenly distributed along the rostro-caudal axis of the PAG, but concentrated in its posterior and ventrolateral segments. Optogenetic projection targeting demonstrated that the PAG-to-VTA pathway is predominantly excitatory and targets similar proportions of Ih-expressing VTA DA and GABA neurons. Taken together, these results set the framework for functional analysis of the interplay between PAG and VTA in the regulation of reward and aversion.

scholarly journals Zebrafish Cre/lox regulated UFlip alleles generated by CRISPR/Cas targeted integration provide cell-type specific conditional gene inactivation

2021 ◽  
Author(s):  
Maira P. Almeida ◽  
Sekhar Kambakam ◽  
Fang Liu ◽  
Zhitao Ming ◽  
Jordan M. Welker ◽  
...  
Keyword(s):  
Gene Function ◽  
Cre Recombinase ◽  
Gene Trap ◽  
Gene Inactivation ◽  
Loss Of Function ◽  
Cell Type ◽  
Active Gene ◽  
Indel Mutation ◽  
Targeted Integration ◽  
Cell Type Specific

The ability to regulate gene activity spatially and temporally is essential to investigate cell type specific gene function during development and in postembryonic processes and disease models. The Cre/lox system has been widely used for performing cell and tissue-specific conditional analysis of gene function in zebrafish, but simple and efficient methods for isolation of stable, Cre/lox regulated alleles are lacking. Here we applied our GeneWeld CRISPR/Cas9 short homology-directed targeted integration strategy to generate floxed conditional alleles that provide robust gene knockdown and strong loss of function phenotypes. A universal targeting vector, UFlip, with sites for cloning short 24-48 bp homology arms flanking a floxed mRFP gene trap plus secondary reporter cassette, was integrated into an intron in hdac1, rbbp4, and rb1. Active, gene off orientation hdac1-UFlip-Off and rb1-UFlip-Off integration alleles result in >99% reduction of gene expression in homozygotes and recapitulate known indel loss of function phenotypes. Passive, gene on orientation rbbp4-UFlip-On and rb1-UFlip-On integration alleles do not cause phenotypes in trans-heterozygous combination with an indel mutation. Cre recombinase injection leads to recombination at alternating pairs of loxP and lox2272 sites, inverting and locking the cassette into the active, gene off orientation, and the expected mutant phenotypes. In combination with our endogenous neural progenitor Cre drivers we demonstrate rbbp4-UFlip-On and rb1-UFlip-On gene inactivation phenotypes can be restricted to specific neural cell populations. Replacement of the UFlip mRFP primary reporter gene trap with a 2A-RFP in rbbp4-UFlip-Off, or 2A-KalTA4 in rb1-UFlip-Off, shows strong RFP expression in wild type or UAS:RFP injected embryos, respectively. Together these results validate a simplified approach for efficient isolation of highly mutagenic Cre/lox responsive conditional gene alleles to advance zebrafish Cre recombinase genetics.

scholarly journals Cell Type-Specific Role of RNA Nuclease SMG6 in Neurogenesis

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3365
Author(s):  
Gabriela Maria Guerra ◽  
Doreen May ◽  
Torsten Kroll ◽  
Philipp Koch ◽  
Marco Groth ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cell Fate ◽  
Cortical Neurons ◽  
Embryonic Stem ◽  
Normal Structure ◽  
Mutant Mice ◽  
Cell Type ◽  
Nonsense Mediated Mrna Decay ◽  
A Cell ◽  
Cell Type Specific

SMG6 is an endonuclease, which cleaves mRNAs during nonsense-mediated mRNA decay (NMD), thereby regulating gene expression and controling mRNA quality. SMG6 has been shown as a differentiation license factor of totipotent embryonic stem cells. To investigate whether it controls the differentiation of lineage-specific pluripotent progenitor cells, we inactivated Smg6 in murine embryonic neural stem cells. Nestin-Cre-mediated deletion of Smg6 in mouse neuroprogenitor cells (NPCs) caused perinatal lethality. Mutant mice brains showed normal structure at E14.5 but great reduction of the cortical NPCs and late-born cortical neurons during later stages of neurogenesis (i.e., E18.5). Smg6 inactivation led to dramatic cell death in ganglionic eminence (GE) and a reduction of interneurons at E14.5. Interestingly, neurosphere assays showed self-renewal defects specifically in interneuron progenitors but not in cortical NPCs. RT-qPCR analysis revealed that the interneuron differentiation regulators Dlx1 and Dlx2 were reduced after Smg6 deletion. Intriguingly, when Smg6 was deleted specifically in cortical and hippocampal progenitors, the mutant mice were viable and showed normal size and architecture of the cortex at E18.5. Thus, SMG6 regulates cell fate in a cell type-specific manner and is more important for neuroprogenitors originating from the GE than for progenitors from the cortex.

scholarly journals Target-specific M1 inputs to infragranular S1 pyramidal neurons

2016 ◽  
Vol 116 (3) ◽  
pp. 1261-1274 ◽  
Author(s):  
Amanda K. Kinnischtzke ◽  
Erika E. Fanselow ◽  
Daniel J. Simons
Keyword(s):  
Primary Motor Cortex ◽  
Pyramidal Neurons ◽  
Projection Neurons ◽  
Cell Type ◽  
Intrinsic Properties ◽  
Subcortical Structures ◽  
Medial Nucleus ◽  
Cell Type Specific ◽  
Posterior Medial Nucleus

The functional role of input from the primary motor cortex (M1) to primary somatosensory cortex (S1) is unclear; one key to understanding this pathway may lie in elucidating the cell-type specific microcircuits that connect S1 and M1. Recently, we discovered that a subset of pyramidal neurons in the infragranular layers of S1 receive especially strong input from M1 (Kinnischtzke AK, Simons DJ, Fanselow EE. Cereb Cortex 24: 2237–2248, 2014), suggesting that M1 may affect specific classes of pyramidal neurons differently. Here, using combined optogenetic and retrograde labeling approaches in the mouse, we examined the strengths of M1 inputs to five classes of infragranular S1 neurons categorized by their projections to particular cortical and subcortical targets. We found that the magnitude of M1 synaptic input to S1 pyramidal neurons varies greatly depending on the projection target of the postsynaptic neuron. Of the populations examined, M1-projecting corticocortical neurons in L6 received the strongest M1 inputs, whereas ventral posterior medial nucleus-projecting corticothalamic neurons, also located in L6, received the weakest. Each population also possessed distinct intrinsic properties. The results suggest that M1 differentially engages specific classes of S1 projection neurons, thereby regulating the motor-related influence S1 exerts over subcortical structures.

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