Pancani, T;Day, M;Tkatch, T;Wokosin, DL;González-Rodríguez, P;Kondapalli, J;Xie, Z;Chen, Y;Beaumont, V;Surmeier, DJ;
PMID: 36914640 | DOI: 10.1038/s41467-023-36556-3
Huntington's disease (HD) is a progressive, neurodegenerative disease caused by a CAG triplet expansion in huntingtin. Although corticostriatal dysfunction has long been implicated in HD, the determinants and pathway specificity of this pathophysiology are not fully understood. Here, using a male zQ175+/- knock-in mouse model of HD we carry out optogenetic interrogation of intratelencephalic and pyramidal tract synapses with principal striatal spiny projection neurons (SPNs). These studies reveal that the connectivity of intratelencephalic, but not pyramidal tract, neurons with direct and indirect pathway SPNs increased in early symptomatic zQ175+/- HD mice. This enhancement was attributable to reduced pre-synaptic inhibitory control of intratelencephalic terminals by striatal cholinergic interneurons. Lowering mutant huntingtin selectively in striatal cholinergic interneurons with a virally-delivered zinc finger repressor protein normalized striatal acetylcholine release and intratelencephalic functional connectivity, revealing a node in the network underlying corticostriatal pathophysiology in a HD mouse model.
Brain : a journal of neurology
Wlaschin, JJ;Donahue, C;Gluski, J;Osborne, JF;Ramos, LM;Silberberg, H;Le Pichon, CE;
PMID: 36342754 | DOI: 10.1093/brain/awac415
Amyotrophic lateral sclerosis or ALS is a devastating and fatal neurodegenerative disease of motor neurons with very few treatment options. We had previously found that motor neuron degeneration in a mouse model of ALS can be delayed by deleting the axon damage sensor MAP3K12 or Dual Leucine Zipper Kinase (DLK)1. However, DLK is also involved in axon regeneration2-5, prompting us to ask whether combining DLK deletion with a way to promote axon regeneration would result in greater motor neuron protection. To achieve this, we used a mouse line that constitutively expresses ATF3, a master regulator of regeneration in neurons6,7. Although there is precedence for each individual strategy in the SOD1G93A mouse model of ALS1,8, these have not previously been combined. By several lines of evidence including motor neuron electrophysiology, histology and behavior, we observed a powerful synergy when combining DLK deletion with ATF3 expression. The combinatorial strategy resulted in significant protection of motor neurons with fewer undergoing cell death, reduced axon degeneration, and preservation of motor function and connectivity to muscle. This study provides a demonstration of the power of combinatorial therapy to treat neurodegenerative disease.
Morris, C;Watkins, D;Shah, N;Pennington, T;Hens, B;Qi, G;Doud, E;Mosley, A;Atwood, B;Baucum, A;
| DOI: 10.1016/j.biopsych.2022.12.008
Background Grooming dysfunction is a hallmark of the obsessive-compulsive spectrum disorder, trichotillomania. Numerous preclinical studies have utilized SAPAP3 deficient mice for understanding the neurobiology of repetitive grooming, suggesting excessive grooming is caused by increased metabotropic glutamate receptor 5 (mGluR5) activity in striatal direct- and indirect pathway medium spiny neurons (dMSNs and iMSNs, respectively). However, MSN subtype-specific signaling mechanisms that mediate mGluR5-dependent adaptations underlying excessive grooming are not fully understood. Here, we investigate the MSN subtype-specific roles of the striatal signaling hub protein, spinophilin, in mediating repetitive motor dysfunction associated with mGluR5 function. Methods Quantitative proteomics and immunoblotting were utilized to identify how spinophilin impacts mGluR5 phosphorylation and protein interaction changes. Plasticity and repetitive motor dysfunction associated with mGluR5 action was measured using our novel conditional spinophilin mouse model that had spinophilin knocked out from striatal dMSNs or/and iMSNs. Results Loss of spinophilin only in iMSNs decreased performance of a novel motor repertoire, but loss of spinophilin in either MSN subtype abrogated striatal plasticity associated with mGluR5 function and prevented excessive grooming caused by SAPAP3 knockout mice or treatment with the mGluR5-specific positive allosteric modulator (VU0360172) without impacting locomotion-relevant behavior. Biochemically, we determined the spinophilin-mGluR5 interaction correlates with grooming behavior and loss of spinophilin shifts mGluR5 interactions from lipid-raft associated proteins toward postsynaptic density (PSD) proteins implicated in psychiatric disorders. Conclusions These results identify spinophilin as a novel striatal signaling hub molecule in MSNs that cell subtype-specifically mediates behavioral, functional, and molecular adaptations associated with repetitive motor dysfunction in psychiatric disorders.
Matson, KJE;Russ, DE;Kathe, C;Hua, I;Maric, D;Ding, Y;Krynitsky, J;Pursley, R;Sathyamurthy, A;Squair, JW;Levi, BP;Courtine, G;Levine, AJ;
PMID: 36163250 | DOI: 10.1038/s41467-022-33184-1
After spinal cord injury, tissue distal to the lesion contains undamaged cells that could support or augment recovery. Targeting these cells requires a clearer understanding of their injury responses and capacity for repair. Here, we use single nucleus RNA sequencing to profile how each cell type in the lumbar spinal cord changes after a thoracic injury in mice. We present an atlas of these dynamic responses across dozens of cell types in the acute, subacute, and chronically injured spinal cord. Using this resource, we find rare spinal neurons that express a signature of regeneration in response to injury, including a major population that represent spinocerebellar projection neurons. We characterize these cells anatomically and observed axonal sparing, outgrowth, and remodeling in the spinal cord and cerebellum. Together, this work provides a key resource for studying cellular responses to injury and uncovers the spontaneous plasticity of spinocerebellar neurons, uncovering a potential candidate for targeted therapy.
Ghosh A, Syed SM, Tanwar PS.
PMID: 28743800 | DOI: 10.1242/dev.149989
The epithelial lining of the Fallopian tube is vital for fertility, providing nutrition to gametes, and facilitating their transport. It is composed of two major cell types: secretory cells and ciliated cells. Interestingly, human ovarian cancer precursor lesions are primarily consisting of secretory cells. It is unclear why secretory cells are the dominant cell type in these lesions. Additionally, the underlying mechanisms governing Fallopian tube epithelial homoeostasis are currently unknown. In the present study, we showed that across the different developmental stages of mouse oviduct, secretory cells are the most frequently dividing cells of the oviductal epithelium. In vivo genetic cell lineage tracing showed that secretory cells not only self-renew, but also give rise to ciliated cells. Analysis of a Wnt reporter mouse model and different Wnt target genes showed that the Wnt signaling pathway is involved in oviductal epithelial homoeostasis. By developing two triple transgenic mouse models, we showed that Wnt/β-catenin signaling is essential for self-renewal as well as differentiation of secretory cells. In summary, our results provide mechanistic insight into oviductal epithelial homoeostasis.
Sci Transl Med. 2018 Oct 31;10(465).
Borel F, Gernoux G, Sun H, Stock R, Blackwood M, Brown RH Jr, Mueller C.
PMID: 30381409 | DOI: 10.1126/scitranslmed.aau6414
Amyotrophic lateral sclerosis (ALS) is a fatal neurological disease caused by degeneration of motor neurons leading to rapidly progressive paralysis. About 10% of cases are caused by gain-of-function mutations that are transmitted as dominant traits. A potential therapy for these cases is to suppress the expression of the mutant gene. Here, we investigated silencing of SOD1, a gene commonly mutated in familial ALS, using an adeno-associated virus (AAV) encoding an artificial microRNA (miRNA) that targeted SOD1 In a superoxide dismutase 1 (SOD1)-mediated mouse model of ALS, we have previously demonstrated that SOD1 silencing delayed disease onset, increased survival time, and reduced muscle loss and motor and respiratory impairments. Here, we describe the preclinical characterization of this approach in cynomolgus macaques (Macaca fascicularis) using an AAV serotype for delivery that has been shown to be safe in clinical trials. We optimized AAV delivery to the spinal cord by preimplantation of a catheter and placement of the subject with head down at 30 degrees during intrathecal infusion. We compared different promoters for the expression of artificial miRNAs directed against mutant SOD1 Results demonstrated efficient delivery and effective silencing of the SOD1 gene in motor neurons. These results support the notion that gene therapy with an artificial miRNA targeting SOD1 is safe and merits further development for the treatment of mutant SOD1-linked ALS.
Xhima K, Markham-Coultes K, Nedev H, Heinen S, Saragovi HU, Hynynen K, Aubert I
PMID: 32010781 | DOI: 10.1126/sciadv.aax6646
Free PMC Article
The degeneration of cholinergic neurons is a prominent feature of Alzheimer's disease (AD). In animal models of injury and aging, nerve growth factor (NGF) enhances cholinergic cell survival and function, contributing to improved memory. In the presence of AD pathology, however, NGF-related therapeutics have yet to fulfill their regenerative potential. We propose that stimulating the TrkA receptor, without p75NTR activation, is key for therapeutic efficacy. Supporting this hypothesis, the selective TrkA agonist D3 rescued neurotrophin signaling in TgCRND8 mice, whereas NGF, interacting with both TrkA and p75NTR, did not. D3, delivered intravenously and noninvasively to the basal forebrain using MRI-guided focused ultrasound (MRIgFUS)-mediated blood-brain barrier (BBB) permeability activated TrkA-related signaling cascades and enhanced cholinergic neurotransmission. Recent clinical trials support the safety and feasibility of MRIgFUS BBB modulation in AD patients. Neuroprotective agents targeting TrkA, combined with MRIgFUS BBB modulation, represent a promising strategy to counter neurodegeneration in AD.
Yao, Y;Barger, Z;Saffari Doost, M;Tso, CF;Darmohray, D;Silverman, D;Liu, D;Ma, C;Cetin, A;Yao, S;Zeng, H;Dan, Y;
PMID: 36170850 | DOI: 10.1016/j.neuron.2022.08.027
Sleep disturbances are strongly associated with cardiovascular diseases. Baroreflex, a basic cardiovascular regulation mechanism, is modulated by sleep-wake states. Here, we show that neurons at key stages of baroreflex pathways also promote sleep. Using activity-dependent genetic labeling, we tagged neurons in the nucleus of the solitary tract (NST) activated by blood pressure elevation and confirmed their barosensitivity with optrode recording and calcium imaging. Chemogenetic or optogenetic activation of these neurons promoted non-REM sleep in addition to decreasing blood pressure and heart rate. GABAergic neurons in the caudal ventrolateral medulla (CVLM)-a downstream target of the NST for vasomotor baroreflex-also promote non-REM sleep, partly by inhibiting the sympathoexcitatory and wake-promoting adrenergic neurons in the rostral ventrolateral medulla (RVLM). Cholinergic neurons in the nucleus ambiguous-a target of the NST for cardiac baroreflex-promoted non-REM sleep as well. Thus, key components of the cardiovascular baroreflex circuit are also integral to sleep-wake brain-state regulation.
Zhang, CH;Gao, Y;Hung, HH;Zhuo, Z;Grodzinsky, AJ;Lassar, AB;
PMID: 36435829 | DOI: 10.1038/s41467-022-35010-0
While prior work has established that articular cartilage arises from Prg4-expressing perichondrial cells, it is not clear how this process is specifically restricted to the perichondrium of synovial joints. We document that the transcription factor Creb5 is necessary to initiate the expression of signaling molecules that both direct the formation of synovial joints and guide perichondrial tissue to form articular cartilage instead of bone. Creb5 promotes the generation of articular chondrocytes from perichondrial precursors in part by inducing expression of signaling molecules that block a Wnt5a autoregulatory loop in the perichondrium. Postnatal deletion of Creb5 in the articular cartilage leads to loss of both flat superficial zone articular chondrocytes coupled with a loss of both Prg4 and Wif1 expression in the articular cartilage; and a non-cell autonomous up-regulation of Ctgf. Our findings indicate that Creb5 promotes joint formation and the subsequent development of articular chondrocytes by driving the expression of signaling molecules that both specify the joint interzone and simultaneously inhibit a Wnt5a positive-feedback loop in the perichondrium.
Apc-mutant cells act as supercompetitors in intestinal tumour initiation
van Neerven, SM;de Groot, NE;Nijman, LE;Scicluna, BP;van Driel, MS;Lecca, MC;Warmerdam, DO;Kakkar, V;Moreno, LF;Vieira Braga, FA;Sanches, DR;Ramesh, P;Ten Hoorn, S;Aelvoet, AS;van Boxel, MF;Koens, L;Krawczyk, PM;Koster, J;Dekker, E;Medema, JP;Winton, DJ;Bijlsma, MF;Morrissey, E;Léveillé, N;Vermeulen, L;
PMID: 34079128 | DOI: 10.1038/s41586-021-03558-4
A delicate equilibrium of WNT agonists and antagonists in the intestinal stem cell (ISC) niche is critical to maintaining the ISC compartment, as it accommodates the rapid renewal of the gut lining. Disruption of this balance by mutations in the tumour suppressor gene APC, which are found in approximately 80% of all human colon cancers, leads to unrestrained activation of the WNT pathway1,2. It has previously been established that Apc-mutant cells have a competitive advantage over wild-type ISCs3. Consequently, Apc-mutant ISCs frequently outcompete all wild-type stem cells within a crypt, thereby reaching clonal fixation in the tissue and initiating cancer formation. However, whether the increased relative fitness of Apc-mutant ISCs involves only cell-intrinsic features or whether Apc mutants are actively involved in the elimination of their wild-type neighbours remains unresolved. Here we show that Apc-mutant ISCs function as bona fide supercompetitors by secreting WNT antagonists, thereby inducing differentiation of neighbouring wild-type ISCs. Lithium chloride prevented the expansion of Apc-mutant clones and the formation of adenomas by rendering wild-type ISCs insensitive to WNT antagonists through downstream activation of WNT by inhibition of GSK3β. Our work suggests that boosting the fitness of healthy cells to limit the expansion of pre-malignant clones may be a powerful strategy to limit the formation of cancers in high-risk individuals.
Fluri F, Malzahn U, Homola GA, Schuhmann MK, Kleinschnitz C, Volkmann J.
PMID: 29059697 | DOI: 10.1002/ana.25086
Abstract
OBJECTIVE:
One-third of all stroke survivors are unable to walk, even after intensive physiotherapy. Thus, other concepts to restore walking are needed. Since electrical stimulation of the mesencephalic locomotor region (MLR) is known to elicit gait movements, this area might be a promising target for restorative neurostimulation in stroke patients with gait disability. The present study aims to delineate the effect of high-frequency stimulation of the MLR (MLR-HFS) on gait impairment in a rodent stroke model.
METHODS:
Male Wistar rats underwent photothrombotic stroke of the right sensorimotor cortex and chronic implantation of a stimulating electrode into the right MLR. Gait was assessed using clinical scoring of the beam walking test and videokinematic analysis (CatWalk™) at baseline and on days 3 and 4 after experimental stroke with and without MLR-HFS.
RESULTS:
Kinematic analysis revealed significant changes in several dynamic and static gait parameters resulting in overall reduced gait velocity. All rats exhibited major coordination deficits during the beam walking challenge and were unable to cross the beam. Simultaneous to the onset of MLR-HFS, a significantly higher walking speed and improvements in several dynamic gait parameters were detected by the Catwalk™-system. Rats regained the ability to cross the beam unassisted showing a reduced number of paw slips and misses.
INTERPRETATION:
MLR-HFS can improve disordered locomotor function in a rodent stroke model. It may act by shielding brainstem and spinal locomotor centers from abnormal cortical input after stroke, thus allowing for compensatory and independent action of these circuits.
AAV9-mediated FIG4 delivery prolongs life span in Charcot Marie Tooth disease type 4J mouse model
The Journal of clinical investigation
Presa, M;Bailey, RM;Davis, C;Murphy, T;Cook, J;Walls, R;Wilpan, H;Bogdanik, L;Lenk, GM;Burgess, RW;Gray, SJ;Lutz, C;
PMID: 33878035 | DOI: 10.1172/JCI137159
Charcot-Marie-Tooth disease type 4J (CMT4J) is caused by recessive, loss-of-function mutations in FIG4, encoding a phosphoinositol(3,5)P2-phosphatase. CMT4J patients have both neuron loss and demyelination in the peripheral nervous system, with vacuolization indicative of endosome/lysosome trafficking defects. Although the disease is highly variable, the onset is often in childhood and FIG4 mutations can dramatically shorten lifespan. There is currently no treatment for CMT4J. Here we present the results of preclinical studies testing a gene therapy approach to restore FIG4 expression. A mouse model of CMT4J, the Fig4-pale tremor (plt) allele, was dosed with a single-stranded AAV9 to deliver a codon-optimized human FIG4 sequence. Untreated, Fig4plt/plt mice have a median survival of approximately 5 weeks. When treated with the AAV9-FIG4 vector at postnatal day 1 or 4, mice survived at least one year, with largely normal gross motor performance and little sign of neuropathy by neurophysiological or histopathological evaluation. When treated at postnatal day 7 or 11, life span was still significantly prolonged and peripheral nerve function was improved, but rescue was less complete. No unanticipated adverse effects were observed. Therefore, AAV9-mediated delivery of FIG4 is a well-tolerated and efficacious strategy in a mouse model of CMT4J.
