scholarly journals Network analysis of the progranulin-deficient mouse brain proteome reveals pathogenic mechanisms shared in human frontotemporal dementia caused by GRN mutations

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Meixiang Huang ◽  
Erica Modeste ◽  
Eric Dammer ◽  
Paola Merino ◽  
Georgia Taylor ◽  
...  
Keyword(s):  
Network Analysis ◽  
Frontotemporal Dementia ◽  
Mouse Brain ◽  
Neuronal Ceroid Lipofuscinosis ◽  
Disease Onset ◽  
Loss Of Function ◽  
Lysosomal Dysfunction ◽  
Brain Proteome ◽  
Galectin 3 ◽  
Lysosomal Proteins

Abstract Heterozygous, loss-of-function mutations in the granulin gene (GRN) encoding progranulin (PGRN) are a common cause of frontotemporal dementia (FTD). Homozygous GRN mutations cause neuronal ceroid lipofuscinosis-11 (CLN11), a lysosome storage disease. PGRN is a secreted glycoprotein that can be proteolytically cleaved into seven bioactive 6 kDa granulins. However, it is unclear how deficiency of PGRN and granulins causes neurodegeneration. To gain insight into the mechanisms of FTD pathogenesis, we utilized Tandem Mass Tag isobaric labeling mass spectrometry to perform an unbiased quantitative proteomic analysis of whole-brain tissue from wild type (Grn+/+) and Grn knockout (Grn−/−) mice at 3- and 19-months of age. At 3-months lysosomal proteins (i.e. Gns, Scarb2, Hexb) are selectively increased indicating lysosomal dysfunction is an early consequence of PGRN deficiency. Additionally, proteins involved in lipid metabolism (Acly, Apoc3, Asah1, Gpld1, Ppt1, and Naaa) are decreased; suggesting lysosomal degradation of lipids may be impaired in the Grn−/− brain. Systems biology using weighted correlation network analysis (WGCNA) of the Grn−/− brain proteome identified 26 modules of highly co-expressed proteins. Three modules strongly correlated to Grn deficiency and were enriched with lysosomal proteins (Gpnmb, CtsD, CtsZ, and Tpp1) and inflammatory proteins (Lgals3, GFAP, CD44, S100a, and C1qa). We find that lysosomal dysregulation is exacerbated with age in the Grn−/− mouse brain leading to neuroinflammation, synaptic loss, and decreased markers of oligodendrocytes, myelin, and neurons. In particular, GPNMB and LGALS3 (galectin-3) were upregulated by microglia and elevated in FTD-GRN brain samples, indicating common pathogenic pathways are dysregulated in human FTD cases and Grn−/− mice. GPNMB levels were significantly increased in the cerebrospinal fluid of FTD-GRN patients, but not in MAPT or C9orf72 carriers, suggesting GPNMB could be a biomarker specific to FTD-GRN to monitor disease onset, progression, and drug response. Our findings support the idea that insufficiency of PGRN and granulins in humans causes neurodegeneration through lysosomal dysfunction, defects in autophagy, and neuroinflammation, which could be targeted to develop effective therapies.

scholarly journals Network analysis of the brain proteome of GRN knockout mice reveals pathogenic mechanisms shared in human frontotemporal dementia caused by GRN mutations

2020 ◽  
Vol 16 (S3) ◽  
Author(s):  
Thomas Kukar ◽  
Meixiang Huang ◽  
Erica S Modeste ◽  
Eric B Dammer ◽  
Christopher J Holler ◽  
...  
Keyword(s):  
Network Analysis ◽  
Frontotemporal Dementia ◽  
Knockout Mice ◽  
Pathogenic Mechanisms ◽  
Brain Proteome ◽  
The Brain

scholarly journals Impaired β-glucocerebrosidase activity and processing in frontotemporal dementia due to progranulin mutations

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Andrew E. Arrant ◽  
Jonathan R. Roth ◽  
Nicholas R. Boyle ◽  
Shreya N. Kashyap ◽  
Madelyn Q. Hoffmann ◽  
...  
Keyword(s):  
Frontotemporal Dementia ◽  
Posttranslational Modifications ◽  
Neuronal Ceroid Lipofuscinosis ◽  
Inferior Frontal Gyrus ◽  
Lysosomal Storage ◽  
Loss Of Function ◽  
Wild Type ◽  
Metabolizing Enzymes ◽  
Dementia Patients ◽  
The Brain

AbstractLoss-of-function mutations in progranulin (GRN) are a major autosomal dominant cause of frontotemporal dementia. Most pathogenic GRN mutations result in progranulin haploinsufficiency, which is thought to cause frontotemporal dementia in GRN mutation carriers. Progranulin haploinsufficiency may drive frontotemporal dementia pathogenesis by disrupting lysosomal function, as patients with GRN mutations on both alleles develop the lysosomal storage disorder neuronal ceroid lipofuscinosis, and frontotemporal dementia patients with GRN mutations (FTD-GRN) also accumulate lipofuscin. The specific lysosomal deficits caused by progranulin insufficiency remain unclear, but emerging data indicate that progranulin insufficiency may impair lysosomal sphingolipid-metabolizing enzymes. We investigated the effects of progranulin insufficiency on sphingolipid-metabolizing enzymes in the inferior frontal gyrus of FTD-GRN patients using fluorogenic activity assays, biochemical profiling of enzyme levels and posttranslational modifications, and quantitative neuropathology. Of the enzymes studied, only β-glucocerebrosidase exhibited impairment in FTD-GRN patients. Brains from FTD-GRN patients had lower activity than controls, which was associated with lower levels of mature β-glucocerebrosidase protein and accumulation of insoluble, incompletely glycosylated β-glucocerebrosidase. Immunostaining revealed loss of neuronal β-glucocerebrosidase in FTD-GRN patients. To investigate the effects of progranulin insufficiency on β-glucocerebrosidase outside of the context of neurodegeneration, we investigated β-glucocerebrosidase activity in progranulin-insufficient mice. Brains from Grn−/− mice had lower β-glucocerebrosidase activity than wild-type littermates, which was corrected by AAV-progranulin gene therapy. These data show that progranulin insufficiency impairs β-glucocerebrosidase activity in the brain. This effect is strongest in neurons and may be caused by impaired β-glucocerebrosidase processing.

scholarly journals Kinetic Analysis of Mouse Brain Proteome Alterations Following Chikungunya Virus Infection before and after Appearance of Clinical Symptoms

PLoS ONE ◽  
2014 ◽  
Vol 9 (3) ◽  
pp. e91397 ◽  
Author(s):  
Christophe Fraisier ◽  
Penelope Koraka ◽  
Maya Belghazi ◽  
Mahfoud Bakli ◽  
Samuel Granjeaud ◽  
...  
Keyword(s):  
Virus Infection ◽  
Kinetic Analysis ◽  
Mouse Brain ◽  
Chikungunya Virus ◽  
Clinical Symptoms ◽  
Before And After ◽  
Brain Proteome

scholarly journals Loss of TBK1 activity leads to TDP-43 proteinopathy through lysosomal dysfunction in human motor neurons

2021 ◽  
Author(s):  
Jin Hao ◽  
Michael F Wells ◽  
Gengle Niu ◽  
Irune Guerra San Juan ◽  
Francesco Limone ◽  
...  
Keyword(s):  
Motor Neuron ◽  
Neurodegenerative Disease ◽  
Motor Neurons ◽  
Inhibition Mechanism ◽  
Loss Of Function ◽  
Neurodegenerative Process ◽  
Lysosomal Dysfunction ◽  
Human Motor ◽  
Lateral Sclerosis ◽  
Lysosomal Acidification

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by motor neuron loss accompanied by cytoplasmic localization of TDP-43 proteins and their insoluble accumulations. Haploinsufficiency of TBK1 has been found to associate with or cause ALS. However, the cell-autonomous mechanisms by which reduced TBK1 activity contributes to human motor neuron pathology remain elusive. Here, we generated a human cellular model harboring loss-of-function mutations of TBK1 by gene editing and found that TBK1 deficiency was sufficient to cause TDP-43 pathology in human motor neurons. In addition to its functions in autophagy, we found that TBK1 interacted with endosomes and was required for normal endosomal maturation and subsequent lysosomal acidification. Surprisingly, TDP-43 pathology resulted more from the dysfunctional endo-lysosomal pathway than the previously recognized autophagy inhibition mechanism. Restoring TBK1 levels ameliorated lysosomal dysfunction and TDP-43 pathology and maintained normal motor neuron homeostasis. Notably, using patient-derived motor neurons, we found that haploinsufficiency of TBK1 sensitized neurons to lysosomal stress, and chemical regulators of endosomal maturation rescued the neurodegenerative process. Together, our results revealed the mechanism of TBK1 in maintaining TDP-43 and motor neuron homeostasis and suggested that modulating endosomal maturation was able to rescue neurodegenerative disease phenotypes caused by TBK1 deficiency.

scholarly journals AAV-mediated progranulin delivery to a mouse model of progranulin deficiency causes T cell-mediated hippocampal degeneration

2018 ◽  
Author(s):  
Defne A. Amado ◽  
Julianne M. Rieders ◽  
Fortunay Diatta ◽  
Pilar Hernandez-Con ◽  
Adina Singer ◽  
...  
Keyword(s):  
T Cell ◽  
Frontotemporal Dementia ◽  
Neuronal Ceroid Lipofuscinosis ◽  
Gene Replacement ◽  
Cell Infiltration ◽  
Great Promise ◽  
Wild Type ◽  
Gene Therapies ◽  
Ceroid Lipofuscinosis ◽  
T Cell Infiltration

AbstractAdeno-associated virus (AAV)-mediated gene replacement is emerging as a safe and effective means of correcting single-gene mutations, and use of AAV vectors for treatment of diseases of the CNS is increasing. AAV-mediated progranulin gene (GRN) delivery has been proposed as a treatment for GRN-deficient frontotemporal dementia (FTD) and neuronal ceroid lipofuscinosis (NCL), and two recent studies using focal intraparenchymal AAV-Grn delivery to brain have shown moderate success in histopathologic and behavioral rescue in mouse FTD models. Here, we used AAV9 to deliver GRN to the lateral ventricle to achieve widespread expression in the Grn null mouse brain. We found that despite a global increase in progranulin throughout many brain regions, overexpression of GRN resulted in dramatic and selective hippocampal toxicity and degeneration affecting both neurons and glia. Histologically, hippocampal degeneration was preceded by T cell infiltration and perivascular cuffing, suggesting an inflammatory component to the ensuing neuronal loss. GRN delivery with an ependymal-targeting AAV for selective secretion of progranulin into the cerebrospinal fluid (CSF) similarly resulted in T cell infiltration as well as ependymal hypertrophy. Interestingly, overexpression of GRN in wild-type animals also provoked T cell infiltration. These results call into question the safety of GRN overexpression in the CNS, with evidence for both a region-selective immune response and cellular proliferative response following GRN gene delivery. Our results highlight the importance of careful consideration of target gene biology and cellular response to overexpression in relevant animal models prior to progressing to the clinic.Significance StatementGene therapies using adeno-associated viral (AAV) vectors show great promise for many human diseases, including diseases that affect the central nervous system (CNS). Frontotemporal dementia (FTD) and neuronal ceroid lipofuscinosis (NCL) are neurodegenerative diseases resulting from loss of one or both copies of the gene encoding progranulin (GRN), and gene replacement has been proposed for these currently untreatable disorders. Here, we used two different AAV vectors to induce widespread brain GRN expression in mice lacking the gene, as well as in wild-type mice. Unexpectedly, GRN overexpression resulted in T cell infiltration, followed by marked hippocampal neurodegeneration. Our results call into question the safety of GRN overexpression in the CNS, with wider implications for development of CNS gene therapies.

Immunofluorescence of Galectin-3 Puncta after lysosomal damage with LLoMe v1

2021 ◽  
Author(s):  
Vinay V. Eapen ◽  
Sharan Swarup ◽  
Melissa Hoyer ◽  
Harper not provided JW
Keyword(s):  
Confocal Imaging ◽  
Signaling Proteins ◽  
Membrane Rupture ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
Luminal Side ◽  
Selective Elimination ◽  
Galectin 3 ◽  
Autophagy Pathway ◽  
Lysosomal Proteins

Lysophagy-the selective elimination of damaged lysosomes by the autophagy pathway-is a critical housekeeping mechanism in cells. This pathway surveils lysosomes and selectively demarcates terminally damaged lysosomes for elimination. Among the most upstream signaling proteins in this pathway are the glycan binding proteins-Galectins-which recognize N and O linked glycan chains on the luminal side of transmembrane lysosomal proteins. These glycosyl modifications are only accessible to galectin proteins upon extensive lysosomal membrane rupture and serve as a sensitive measure of lysosomal damage and eventual clearance by selective autophagy. Indeed, prior work has shown that immunofluorescence of Galectin-3 serves as a convenient proxy for lysophagic flux in tissue culture cells (Aits et al., 2015; Maejima et al., 2013). Here we describe our method for monitoring galectin-3 puncta clearance as a proxy for turnover of damaged lysosomes via immunofluorescence and confocal imaging.

Danon Disease

2016 ◽  
Author(s):  
Esther Brusse ◽  
Pascal Laforêt ◽  
Ans T. van der Ploeg
Keyword(s):  
Mental Retardation ◽  
Disease Onset ◽  
Mild Mental Retardation ◽  
Primary Defect ◽  
Danon Disease ◽  
Asymptomatic Patients ◽  
Cardiac Evaluation ◽  
Muscle Disorder ◽  
Lysosomal Proteins ◽  
Female Carriers

Danon disease, like Pompe disease, is a muscle disorder caused by a primary defect in lysosomal proteins. Danon disease (OMIM #300257) is an X-linked dominant disorder, with males being more severely affected than female carriers. In males, mean disease onset is in their early teens and in females in their late twenties. Clinical hallmarks are a severe cardiomyopathy, muscle weakness, and mild mental retardation. Retinal, liver, and pulmonary disease may also occur. Milder, sometimes isolated cardiac phenotypes without mental retardation are also described. Regular cardiac evaluation, even in asymptomatic patients, is obligatory.

scholarly journals Age-dependent emergence of neurophysiological and behavioral abnormalities in progranulin-deficient mice

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Dávid Nagy ◽  
Lauren Herl Martens ◽  
Liza Leventhal ◽  
Angela Chen ◽  
Craig Kelley ◽  
...  
Keyword(s):  
Frontotemporal Dementia ◽  
Neurodegenerative Disorder ◽  
Neuronal Loss ◽  
Loss Of Function ◽  
Behavioral Alterations ◽  
Response Latencies ◽  
Reward Seeking ◽  
Behavioral Abnormalities ◽  
Age Dependent

Abstract Background Loss-of-function mutations in the progranulin gene cause frontotemporal dementia, a genetic, heterogeneous neurodegenerative disorder. Progranulin deficiency leads to extensive neuronal loss in the frontal and temporal lobes, altered synaptic connectivity, and behavioral alterations. Methods The chronological emergence of neurophysiological and behavioral phenotypes of Grn heterozygous and homozygous mice in the dorsomedial thalamic—medial prefrontal cortical pathway were evaluated by in vivo electrophysiology and reward-seeking/processing behavior, tested between ages 3 and 12.5 months. Results Electrophysiological recordings identified a clear age-dependent deficit in the thalamocortical circuit. Both heterozygous and homozygous mice exhibited impaired input-output relationships and paired-pulse depression, but evoked response latencies were only prolonged in heterozygotes. Furthermore, we demonstrate firstly an abnormal reward-seeking/processing behavior in the homozygous mice which correlates with previously reported neuroinflammation. Conclusion Our findings indicate that murine progranulin deficiency causes age-dependent neurophysiological and behavioral abnormalities thereby indicating their validity in modeling aspects of human frontotemporal dementia.

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