Biology subjects

Eultgen, E. M.

Publications and source records attributed to Eultgen, E. M..

4 recordsLinked to original sources

bioRxiv2025

Identifying and treating CLN3 disease outside the central nervous system

Background and aimsSevere gastrointestinal (GI) symptoms occur in people with CLN3 disease, a neurodegenerative disorder. If left untreated these GI symptoms compromise life quality and may contribute to death. We hypothesized GI symptoms in CLN3 disease are at least partially due to neurodegeneration in the enteric nervous system (ENS), the master regulator of bowel function. MethodsWe examined the integrity of the ENS in human CLN3 autopsy small bowel and colon, and in CLN3 deficient (Cln3{Delta}ex7/8) mice. We performed detailed immunohistological analyses of enteric neurons and glia and assessed bowel transit times at multiple disease stages. We then tested the therapeutic potential of neonatal intravenous gene therapy (AAV9-hCLN3) to prevent bowel phenotypes in Cln3{Delta}ex7/8 mice. ResultsHuman CLN3 bowel displayed a profound loss of enteric neurons and their neurites, with pathological effects upon enteric glia. Cln3{Delta}ex7/8 mice had normal appearing ENS at 1 month of age, but then experienced progressive loss of both enteric neurons and glia accompanied by marked bowel distention, resembling the human CLN3 phenotype. Degenerative changes in Cln3{Delta}ex7/8 mouse enteric neurons and glia were largely prevented by systemic neonatal delivery of AAV9-hCLN3 gene therapy, preventing bowel distention at disease endstage. ConclusionsOur findings demonstrate that CLN3 deficiency profoundly damages enteric neurons and glia in both murine and human CLN3 disease, contributing to GI dysfunction. This study provides preclinical evidence that systemic gene therapy may effectively treat multiple aspects of bowel pathology, expanding the therapeutic landscape beyond the CNS. What you need to know: Background and ContextSignificant gastrointestinal (GI) symptoms are evident in many pediatric neurological conditions. We hypothesized that, in addition to central nervous system (CNS) effects, defects in the enteric nervous system (ENS) may underlie these GI symptoms in some neurodegenerative diseases. Revealing such defects would open up new opportunities for treating these life-limiting and debilitating symptoms. New FindingsThe enteric nervous system is significantly impacted in human CLN3 disease, a feature that is recapitulated in CLN3 mice. Progressive enteric neurodegeneration in these mice follows a similar time course to neuron loss in the brain, resulting in severe bowel distention. Nevertheless, bowel distention and the majority of the pathology within the enteric nervous system can be mitigated via neonatal gene therapy. LimitationsOur human data will need to be replicated in larger numbers of CLN3 cases, and methods will need to be developed to treat the human bowel, avoiding the risk of liver tumors. ImpactThese results reveal that a neurodegenerative disease previously thought to primarily affect the CNS, damages the bowels enteric nervous system and that ENS degeneration can be prevented in mice by gene therapy. These data provide a new perspective on this pediatric disorder and may have relevance to other pediatric neurologic diseases. Lay SummaryThe progressive loss of neurons in CLN3 disease is not confined to the brain but also occurs in the bowel enteric nervous system, contributing directly to GI dysfunction. Neurodegeneration in the enteric nervous system can be prevented by treating the bowel with gene therapy.

neuroscience↗

bioRxiv2024

GABAergic interneurons contribute to the fatal seizure phenotype of CLN2 disease mice

GABAergic interneuron deficits have been implicated in the epileptogenesis of multiple neurological diseases. While epileptic seizures are a key clinical hallmark of CLN2 disease, a childhood-onset neurodegenerative lysosomal storage disorder caused by a deficiency of tripeptidyl peptidase 1 (TPP1), the etiology of these seizures remains elusive. Given that Cln2R207X/R207X mice display fatal spontaneous seizures and an early loss of several cortical interneuron populations, we hypothesized that those two events might be causally related. To address this hypothesis, we first generated an inducible transgenic mouse expressing lysosomal membrane-tethered TPP1 (TPP1LAMP1) on the Cln2R207X/R207X genetic background to study the cell-autonomous effects of cell-type-specific TPP1 deficiency. We crossed the TPP1LAMP1 mice with Vgat-Cre mice to introduce interneuron-specific TPP1 deficiency. Vgat-Cre; TPP1LAMP1 mice displayed storage material accumulation in several interneuron populations both in cortex and striatum, and increased susceptibility to die after PTZ-induced seizures. Secondly, to test the role of GABAergic interneuron activity in seizure progression, we selectively activated these cells in Cln2R207X/R207X mice using Designer Receptor Exclusively Activated by Designer Drugs (DREADDs) in in Vgat-Cre: Cln2R207X/R207X mice. EEG monitoring revealed that DREADD-mediated activation of interneurons via chronic deschloroclozapine administration accelerated the onset of spontaneous seizures and seizure-associated death in Vgat-Cre: Cln2R207X/R207X mice, suggesting that modulating interneuron activity can exert influence over epileptiform abnormalities in CLN2 disease. Taken together, these results provide new mechanistic insights into the underlying etiology of seizures and premature death that characterize CLN2 disease.

neuroscience↗

bioRxiv2023

Bowel dysmotility and enteric neuron degeneration in lysosomal storage disease mice is prevented by gene therapy

Background and aimsChildren with neurodegenerative disease often have debilitating gastrointestinal (GI) symptoms that may be due at least in part to underappreciated involvement of neurons in the enteric nervous system (ENS), the master regulator of bowel function. MethodsWe investigated bowel motility in mouse models of CLN1 and CLN2 disease, neurodegenerative lysosomal storage disorders caused by deficiencies in palmitoyl protein thioesterase-1 (PPT1) and tripeptidyl peptidase-1 (TPP1), respectively. We then explored the integrity of ENS anatomy in immunostained bowel wholemount preparations from these mice. Lastly, we administered adeno-associated viral gene therapy to neonatal mice and determined if this would prevent these newly identified bowel phenotypes. ResultsMouse models of CLN1 and CLN2 disease both displayed slow bowel transit in vivo that worsened with age. Although the ENS appeared to develop normally, there was a progressive and profound loss of myenteric plexus neurons accompanied by changes in enteric glia in adult mice. Neonatal administration of adeno-associated virus-mediated gene therapy prevented bowel transit defects and the loss of many ENS neurons. ConclusionsWe show that two neurodegenerative lysosomal storage diseases cause profound and progressive damage to the mouse enteric nervous system and impair bowel motility. We also provide proof-of-principle evidence that gene therapy can prevent enteric nervous system disease. This study may have general therapeutic implications for many inherited neurodegenerative disorders. What you need to knowO_ST_ABSBackground and ContextC_ST_ABSMany pediatric central nervous system disorders also have debilitating gastrointestinal symptoms. For most of these diseases, it is not known if the enteric nervous system (ENS) is also affected and to what degree ENS defects contribute to GI symptoms. To date, no attempts have been made to directly treat or prevent enteric nervous system disease via gene therapy. New FindingsThe enteric nervous system is severely affected in mouse models of CLN1 and CLN2 disease, profoundly neurodegenerative lysosomal storage disorders. Bowel transit defects and most of the enteric nervous system pathology can be prevented by neonatal administration of gene therapy. LimitationsInformation about enteric nervous system disease in human children is still lacking, and methods will need to be developed to treat the human bowel. ImpactThese findings identify an underappreciated effect of neurodegenerative disease upon the bowel and demonstrate that enteric nervous system degeneration can be prevented in mice. This provides a new perspective on these childhood disorders that may be applicable to many other conditions that affect the bowel. Lay SummaryIn childrens diseases where the brain degenerates, nerve cells in the bowel also die causing gastrointestinal problems, but this can be prevented by gene therapy.

neuroscience↗

bioRxiv2022

Cortical interneuron loss and seizure generation as novel clinically relevant disease phenotypes in Cln2R207X mice

AimsCLN2 disease is a fatal inherited childhood neurodegenerative disorder. Although a disease-modifying therapy now exists, a fundamental lack of understanding of disease pathogenesis has hampered development of more effective therapies. To better understand the cellular pathophysiology of CLN2 disease, we investigated the nature and progression of neuropathological and neurological changes in the recently generated Cln2R207X mouse. MethodsWe have detailed microglial activation, astrogliosis, cytokine and chemokine expression, and neuron loss across the forebrain and spinal cords of Cln2R207X mice, along with quantitative gait analysis. We also performed long-term electroencephalography (EEG) recordings to characterize seizure activity, a clinically-relevant phenotype yet to be defined in any CLN2 disease model. ResultsHistology revealed early localized microglial activation months before neuron loss in the thalamocortical system and spinal cord, which was accompanied by astrogliosis. These pathological changes were more pronounced and occurred in the cortex before the thalamus or spinal cord. There were early-onset and progressive changes in the expression of specific chemokines and cytokines including IL-33, IP-10, and MIP-1. Gait analysis revealed impaired performance only at disease end stage. EEG recordings revealed robust and progressive epileptiform activity from disease mid-stage including spontaneous seizures, which were accompanied by a profound loss of cortical GABAergic interneurons. ConclusionsOur data reveal novel phenotypes in Cln2R207X mice that differ markedly in their timing and progression through the CNS from other NCL mouse models. Our findings provide new insights on CLN2 disease pathogenesis and clinically-relevant readouts for future therapeutic studies.

neuroscience↗