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Lee HE, Jung M, Choi K, Jang JH, Hwang SK, Chae S, Lee JH, Mun JY. L-serine restored lysosomal failure in cells derived from patients with BPAN reducing iron accumulation with eliminating lipofuscin. Free Radic Biol Med 2024; 221:273-282. [PMID: 38740102 DOI: 10.1016/j.freeradbiomed.2024.05.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 04/30/2024] [Accepted: 05/08/2024] [Indexed: 05/16/2024]
Abstract
Defective mitochondria and autophagy, as well as accumulation of lipid and iron in WDR45 mutant fibroblasts, is related to beta-propeller protein-associated neurodegeneration (BPAN). In this study, we found that enlarged lysosomes in cells derived from patients with BPAN had low enzyme activity, and most of the enlarged lysosomes had an accumulation of iron and oxidized lipid. Cryo-electron tomography revealed elongated lipid accumulation, and spectrometry-based elemental analysis showed that lysosomal iron and oxygen accumulation superimposed with lipid aggregates. Lysosomal lipid aggregates superimposed with autofluorescence as free radical generator, lipofuscin. To eliminate free radical stress by iron accumulation in cells derived from patients with BPAN, we investigated the effects of the iron chelator, 2,2'-bipyridine (bipyridyl, BIP). To study whether the defects in patient-derived cells can be rescued by an iron chelator BIP, we tested whether the level of iron and reactive oxygen species (ROS) in the cells and genes related to oxidative stress were rescued BIP treatment. Although BIP treatment decreased some iron accumulation in the cytoplasm and mitochondria, the accumulation of iron in the lysosomes and levels of cellular ROS were unaffected. In addition, the change of specific RNA levels related to free radical stress in patient fibroblasts was not rescued by BIP. To alleviate free radical stress, we investigated whether l-serine can regulate abnormal structures in cells derived from patients with BPAN through the regulation of free radical stress. l-serine treatment alleviated increase of enlarged lysosomes and iron accumulation and rescued impaired lysosomal activity by reducing oxidized lipid accumulation in the lysosomes of the cells. Lamellated lipids in the lysosomes of the cells were identified as lipofuscin through correlative light and electron microscopy, and l-serine treatment reduced the increase of lipofuscin. These data suggest that l-serine reduces oxidative stress-mediated lysosomal lipid oxidation and iron accumulation by rescuing lysosomal activity.
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Affiliation(s)
- Hye Eun Lee
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu, South Korea; School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Minkyo Jung
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu, South Korea
| | - Kiju Choi
- Division of Structural Biology, Baobab AiBIO, Incheon, South Korea
| | - Jae Hyuck Jang
- Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon, South Korea; Electron Microscopy Group for Materials Science, Korea Basic Science Institute, Daejeon, South Korea
| | - Su-Kyeong Hwang
- Department of Pediatrics, School of Medicine, Kyungpook National University, Daegu, South Korea; Astrogen Inc., Techno-Building 313, Kyungpook National University, Daegu, 41566, South Korea
| | - Sehyun Chae
- Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University, Chuncheon, 24341, South Korea
| | - Jae-Hyeok Lee
- Department of Neurology, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, 50612, South Korea; Medical Research Institute, Pusan National University School of Medicine, Yangsan, 50612, South Korea.
| | - Ji Young Mun
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu, South Korea.
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Mishra S, Morshed N, Kinoshita C, Stevens B, Jayadev S, Young JE. The Alzheimer's disease gene SORL1 regulates lysosome function in human microglia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.25.600648. [PMID: 38979155 PMCID: PMC11230436 DOI: 10.1101/2024.06.25.600648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
The SORL1 gene encodes the sortilin related receptor protein SORLA, a sorting receptor that regulates endo-lysosomal trafficking of various substrates. Loss of function variants in SORL1 are causative for Alzheimer's disease (AD) and decreased expression of SORLA has been repeatedly observed in human AD brains. SORL1 is highly expressed by microglia, the tissue resident immune cells of the brain. Loss of SORLA leads to enlarged lysosomes in hiPSC-derived microglia like cells (hMGLs). However, whether SORLA deficiency contributes to microglia dysfunction and how this is relevant to AD is not known. In this study, we show that loss of SORLA results in decreased lysosomal degradation and lysosomal enzyme activity due to altered trafficking of lysosomal enzymes in hMGLs. Furthermore, lysosomal exocytosis, an important process involved in immune responses and cellular signaling, is also impaired in SORL1 deficient microglia. Phagocytic uptake of fibrillar amyloid beta 1-42 and synaptosomes is increased in SORLA deficient hMGLs, but due to reduced lysosomal degradation, these substrates aberrantly accumulate in lysosomes. Overall, these data highlight the microglial endo-lysosomal network as a potential novel pathway through which SORL1 may increase AD risk and contribute to development of AD. Additionally, our findings may inform development of novel lysosome and microglia associated drug targets for AD.
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Chiu CC, Chen YL, Weng YH, Liu SY, Li HL, Yeh TH, Wang HL. Downregulation of Protease Cathepsin D and Upregulation of Pathologic α-Synuclein Mediate Paucity of DNAJC6-Induced Degeneration of Dopaminergic Neurons. Int J Mol Sci 2024; 25:6711. [PMID: 38928416 PMCID: PMC11204255 DOI: 10.3390/ijms25126711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 06/11/2024] [Accepted: 06/12/2024] [Indexed: 06/28/2024] Open
Abstract
A homozygous mutation of the DNAJC6 gene causes autosomal recessive familial type 19 of Parkinson's disease (PARK19). To test the hypothesis that PARK19 DNAJC6 mutations induce the neurodegeneration of dopaminergic cells by reducing the protein expression of functional DNAJC6 and causing DNAJC6 paucity, an in vitro PARK19 model was constructed by using shRNA-mediated gene silencing of endogenous DANJC6 in differentiated human SH-SY5Y dopaminergic neurons. shRNA targeting DNAJC6 induced the neurodegeneration of dopaminergic cells. DNAJC6 paucity reduced the level of cytosolic clathrin heavy chain and the number of lysosomes in dopaminergic neurons. A DNAJC6 paucity-induced reduction in the lysosomal number downregulated the protein level of lysosomal protease cathepsin D and impaired macroautophagy, resulting in the upregulation of pathologic α-synuclein or phospho-α-synucleinSer129 in the endoplasmic reticulum (ER) and mitochondria. The expression of α-synuclein shRNA or cathepsin D blocked the DNAJC6 deficiency-evoked degeneration of dopaminergic cells. An increase in ER α-synuclein or phospho-α-synucleinSer129 caused by DNAJC6 paucity activated ER stress, the unfolded protein response and ER stress-triggered apoptotic signaling. The lack of DNAJC6-induced upregulation of mitochondrial α-synuclein depolarized the mitochondrial membrane potential and elevated the mitochondrial level of superoxide. The DNAJC6 paucity-evoked ER stress-related apoptotic cascade, mitochondrial malfunction and oxidative stress induced the degeneration of dopaminergic neurons via activating mitochondrial pro-apoptotic signaling. In contrast with the neuroprotective function of WT DNAJC6, the PARK19 DNAJC6 mutants (Q789X or R927G) failed to attenuate the tunicamycin- or rotenone-induced upregulation of pathologic α-synuclein and stimulation of apoptotic signaling. Our data suggest that PARK19 mutation-induced DNAJC6 paucity causes the degeneration of dopaminergic neurons via downregulating protease cathepsin D and upregulating neurotoxic α-synuclein. Our results also indicate that PARK19 mutation (Q789X or R927G) impairs the DNAJC6-mediated neuroprotective function.
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Affiliation(s)
- Ching-Chi Chiu
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan;
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan;
- Healthy Aging Research Center, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Ying-Ling Chen
- Department of Nursing, Chang Gung University of Science and Technology, Taoyuan 33303, Taiwan;
| | - Yi-Hsin Weng
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan;
- Division of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan
- College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Shu-Yu Liu
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, No. 259, Wen-Hwa 1st Road, Kweishan, Taoyuan 33302, Taiwan;
| | - Hon-Lun Li
- Department of Anesthesiology, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan;
| | - Tu-Hsueh Yeh
- Department of Neurology, Taipei Medical University Hospital, Taipei 11031, Taiwan
| | - Hung-Li Wang
- Neuroscience Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan;
- Healthy Aging Research Center, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Division of Movement Disorders, Department of Neurology, Chang Gung Memorial Hospital at Linkou, Taoyuan 33305, Taiwan
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, No. 259, Wen-Hwa 1st Road, Kweishan, Taoyuan 33302, Taiwan;
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Terron HM, Parikh SJ, Abdul-Hay SO, Sahara T, Kang D, Dickson DW, Saftig P, LaFerla FM, Lane S, Leissring MA. Prominent tauopathy and intracellular β-amyloid accumulation triggered by genetic deletion of cathepsin D: implications for Alzheimer disease pathogenesis. Alzheimers Res Ther 2024; 16:70. [PMID: 38575959 PMCID: PMC10996108 DOI: 10.1186/s13195-024-01443-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 03/31/2024] [Indexed: 04/06/2024]
Abstract
BACKGROUND Cathepsin D (CatD) is a lysosomal protease that degrades both the amyloid-β protein (Aβ) and the microtubule-associated protein, tau, which accumulate pathognomonically in Alzheimer disease (AD), but few studies have examined the role of CatD in the development of Aβ pathology and tauopathy in vivo. METHODS CatD knockout (KO) mice were crossed to human amyloid precursor protein (hAPP) transgenic mice, and amyloid burden was quantified by ELISA and immunohistochemistry (IHC). Tauopathy in CatD-KO mice, as initially suggested by Gallyas silver staining, was further characterized by extensive IHC and biochemical analyses. Controls included human tau transgenic mice (JNPL3) and another mouse model of a disease (Krabbe A) characterized by pronounced lysosomal dysfunction. Additional experiments examined the effects of CatD inhibition on tau catabolism in vitro and in cultured neuroblastoma cells with inducible expression of human tau. RESULTS Deletion of CatD in hAPP transgenic mice triggers large increases in cerebral Aβ, manifesting as intense, exclusively intracellular aggregates; extracellular Aβ deposition, by contrast, is neither triggered by CatD deletion, nor affected in older, haploinsufficient mice. Unexpectedly, CatD-KO mice were found to develop prominent tauopathy by just ∼ 3 weeks of age, accumulating sarkosyl-insoluble, hyperphosphorylated tau exceeding the pathology present in aged JNPL3 mice. CatD-KO mice exhibit pronounced perinuclear Gallyas silver staining reminiscent of mature neurofibrillary tangles in human AD, together with widespread phospho-tau immunoreactivity. Striking increases in sarkosyl-insoluble phospho-tau (∼ 1250%) are present in CatD-KO mice but notably absent from Krabbe A mice collected at an identical antemortem interval. In vitro and in cultured cells, we show that tau catabolism is slowed by blockade of CatD proteolytic activity, including via competitive inhibition by Aβ42. CONCLUSIONS Our findings support a major role for CatD in the proteostasis of both Aβ and tau in vivo. To our knowledge, the CatD-KO mouse line is the only model to develop detectable Aβ accumulation and profound tauopathy in the absence of overexpression of hAPP or human tau with disease-associated mutations. Given that tauopathy emerges from disruption of CatD, which can itself be potently inhibited by Aβ42, our findings suggest that impaired CatD activity may represent a key mechanism linking amyloid accumulation and tauopathy in AD.
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Affiliation(s)
- Heather M Terron
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine (UCI MIND), Irvine, CA, 92697, USA
| | - Sagar J Parikh
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine (UCI MIND), Irvine, CA, 92697, USA
| | - Samer O Abdul-Hay
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA
| | - Tomoko Sahara
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA
| | - Dongcheul Kang
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA
| | - Dennis W Dickson
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA
| | - Paul Saftig
- Institut für Biochemie, Christian-Albrechts-Universität zu Kiel, D-24098, Kiel, Germany
| | - Frank M LaFerla
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine (UCI MIND), Irvine, CA, 92697, USA
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, 92697, USA
| | - Shelley Lane
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine (UCI MIND), Irvine, CA, 92697, USA
| | - Malcolm A Leissring
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine (UCI MIND), Irvine, CA, 92697, USA.
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA.
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Marzoog BA. Autophagy as an Anti-senescent in Aging Neurocytes. Curr Mol Med 2024; 24:182-190. [PMID: 36683318 DOI: 10.2174/1566524023666230120102718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 11/23/2022] [Accepted: 11/28/2022] [Indexed: 01/24/2023]
Abstract
Neuron homeostasis is crucial for the organism, and its maintenance is multifactorial, including autophagy. The turnover of aberrant intracellular components is a fundamental pathogenetic mechanism for cell aging. Autophagy is involved in the acceleration of the neurocyte aging process and the modification of cell longevity. Neurocyte aging is a process of loss of cell identity through cellular and subcellular changes that include molecular loss of epigenetics, transcriptomic, proteomic, and autophagy dysfunction. Autophagy dysfunction is the hallmark of neurocyte aging. Cell aging is the credential feature of neurodegenerative diseases. Pathophysiologically, aged neurocytes are characterized by dysregulated autophagy and subsequently neurocyte metabolic stress, resulting in accelerated neurocyte aging. In particular, chaperone- mediated autophagy perturbation results in upregulated expression of aging and apoptosis genes. Aged neurocytes are also characterized by the down-regulation of autophagy-related genes, such as ATG5-ATG12, LC3-II / LC3-I ratio, Beclin-1, and p62. Slowing aging through autophagy targeting is sufficient to improve prognosis in neurodegenerative diseases. Three primary anti-senescent molecules are involved in the aging process: mTOR, AMPK, and Sirtuins. Autophagy therapeutic effects can be applied to reverse and slow aging. This article discusses current advances in the role of autophagy in neurocyte homeostasis, aging, and potential therapeutic strategies to reduce aging and increase cell longevity.
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Affiliation(s)
- Basheer Abdullah Marzoog
- National Research Mordovia State University, Bolshevitskaya Street, 68, Saransk, 430005, Rep. Mordovia, Russia
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Mitsui S, Yamaguchi J, Suzuki C, Uchiyama Y, Tanida I. TUNEL-positive structures in activated microglia and SQSTM1/p62-positive structures in activated astrocytes in the neurodegenerative brain of a CLN10 mouse model. Glia 2023; 71:2753-2769. [PMID: 37571859 DOI: 10.1002/glia.24449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 06/28/2023] [Accepted: 07/20/2023] [Indexed: 08/13/2023]
Abstract
Neuronal ceroid lipofuscinosis is a group of pediatric neurodegenerative diseases. One of their causative genes, CLN10/CtsD, encodes cathepsin D, a major lysosomal protease. Central nervous system (CNS)-specific CtsD-deficient mice exhibit a neurodegenerative disease phenotype with accumulation of ceroid lipofuscins, granular osmiophilic deposits, and SQSTM1/p62. We focused on activated astrocytes and microglia in this neurodegenerative mouse brain, since there are few studies on the relationship between these accumulators and lysosomes in these glial cells. Activated microglia and astrocytes in this mouse thalamus at p24 were increased by approximately 2.5- and 4.6-fold compared with the control, while neurons were decreased by approximately half. Granular osmiophilic deposits were detected in microglial cell bodies and extended their processes in the thalamus. LAMP1-positive lysosomes, but not SQSTM1/p62 aggregates, accumulated in microglia of this mouse thalamus, whereas both lysosomes and SQSTM1/p62 aggregates accumulated in its astrocytes. TUNEL-positive signals were observed mainly in microglia, but few were observed in neurons and astrocytes. These signals were fragmented DNA from degenerated neurons engulfed by microglia or in the lysosomes of microglia. Abnormal autophagic vacuoles also accumulated in the lysosomes of microglia. Granular osmiophilic deposit-like structures localized to LAMP1-positive lysosomes in CtsD-deficient astrocytes. SQSTM1/p62-positive but LAMP1-negative membranous structures also accumulated in the astrocytes and were less condensed than typical granular osmiophilic deposits. These results suggest that CtsD deficiency leads to intracellular abnormalities in activated microglia and astrocytes in addition to neuronal degeneration.
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Affiliation(s)
- Shun Mitsui
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Junji Yamaguchi
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Laboratory of Morphology and Image Analysis, Research Support Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Chigure Suzuki
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yasuo Uchiyama
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Isei Tanida
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Tokyo, Japan
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Terron HM, Parikh SJ, Abdul-Hay SO, Sahara T, Kang D, Dickson DW, Saftig P, LaFerla FM, Lane S, Leissring MA. Prominent tauopathy and intracellular β-amyloid accumulation triggered by genetic deletion of cathepsin D: Implications for Alzheimer disease pathogenesis. RESEARCH SQUARE 2023:rs.3.rs-3464352. [PMID: 37961253 PMCID: PMC10635349 DOI: 10.21203/rs.3.rs-3464352/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Background Cathepsin D (CatD) is a lysosomal protease that degrades both the amyloid-β protein (Aβ) and the microtubule-associated protein, tau, which accumulate pathognomonically in Alzheimer disease (AD), but few studies have examined the role of CatD in the development of Aβ pathology and tauopathy in vivo. Methods CatD knockout (KO) mice were crossed to human amyloid precursor protein (hAPP) transgenic mice, and amyloid burden was quantified by ELISA and immunohistochemistry (IHC). Tauopathy in CatD-KO mice, as initially suggested by Gallyas silver staining, was further characterized by extensive IHC and biochemical analyses. Controls included human tau transgenic mice (JNPL3) and another mouse model characterized by pronounced lysosomal dysfunction (Krabbe A). Additional experiments examined the effects of CatD inhibition on tau catabolism in vitro and in cultured neuroblastoma cells with inducible expression of human tau. Results Deletion of CatD in hAPP transgenic mice triggers large increases in cerebral Aβ, manifesting as intense, exclusively intracellular aggregates; extracellular Aβ deposition, by contrast, is neither triggered by CatD deletion, nor affected in older, haploinsufficient mice. Unexpectedly, CatDKO mice were found to develop prominent tauopathy by just ~ 3 weeks of age, accumulating sarkosyl-insoluble, hyperphosphorylated tau exceeding the pathology in aged JNPL3 mice. CatDKO mice exhibit pronounced perinuclear Gallyas silver staining reminiscent of mature neurofibrillary tangles in human AD, together with widespread phospho-tau immunoreactivity. Striking increases in sarkosyl-insoluble phospho-tau (~ 1250%) are present in CatD-KO mice, but notably absent from Krabbe A mice collected at an identical antemortem interval. In vitro and in cultured cells, we show that tau catabolism is slowed by blockade of CatD proteolytic activity, including via competitive inhibition by Aβ42. Conclusions Our findings support a major role for CatD in the proteostasis of both Aβ and tau in vivo. To our knowledge, CatD-KO mice are the only model to develop detectable Aβ acumulation and profound tauopathy in the absence of overexpression of hAPP or human tau with disease-associated mutations. Given that tauopathy emerges from disruption of CatD, which can itself be potently inhibited by Aβ42, our findings suggest that impaired CatD activity may represent a key mechanism linking amyloid accumulation and tauopathy in AD.
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