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Shorrock HK, Lennon CD, Aliyeva A, Davey EE, DeMeo CC, Pritchard CE, Planco L, Velez JM, Mascorro-Huamancaja A, Shin DS, Cleary JD, Berglund JA. Widespread alternative splicing dysregulation occurs presymptomatically in CAG expansion spinocerebellar ataxias. Brain 2024; 147:486-504. [PMID: 37776516 PMCID: PMC10834251 DOI: 10.1093/brain/awad329] [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: 05/31/2023] [Revised: 07/31/2023] [Accepted: 09/03/2023] [Indexed: 10/02/2023] Open
Abstract
The spinocerebellar ataxias (SCAs) are a group of dominantly inherited neurodegenerative diseases, several of which are caused by CAG expansion mutations (SCAs 1, 2, 3, 6, 7 and 12) and more broadly belong to the large family of over 40 microsatellite expansion diseases. While dysregulation of alternative splicing is a well defined driver of disease pathogenesis across several microsatellite diseases, the contribution of alternative splicing in CAG expansion SCAs is poorly understood. Furthermore, despite extensive studies on differential gene expression, there remains a gap in our understanding of presymptomatic transcriptomic drivers of disease. We sought to address these knowledge gaps through a comprehensive study of 29 publicly available RNA-sequencing datasets. We identified that dysregulation of alternative splicing is widespread across CAG expansion mouse models of SCAs 1, 3 and 7. These changes were detected presymptomatically, persisted throughout disease progression, were repeat length-dependent, and were present in brain regions implicated in SCA pathogenesis including the cerebellum, pons and medulla. Across disease progression, changes in alternative splicing occurred in genes that function in pathways and processes known to be impaired in SCAs, such as ion channels, synaptic signalling, transcriptional regulation and the cytoskeleton. We validated several key alternative splicing events with known functional consequences, including Trpc3 exon 9 and Kcnma1 exon 23b, in the Atxn1154Q/2Q mouse model. Finally, we demonstrated that alternative splicing dysregulation is responsive to therapeutic intervention in CAG expansion SCAs with Atxn1 targeting antisense oligonucleotide rescuing key splicing events. Taken together, these data demonstrate that widespread presymptomatic dysregulation of alternative splicing in CAG expansion SCAs may contribute to disease onset, early neuronal dysfunction and may represent novel biomarkers across this devastating group of neurodegenerative disorders.
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Affiliation(s)
| | - Claudia D Lennon
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
| | - Asmer Aliyeva
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
- Department of Biology, University at Albany—SUNY, Albany, NY 12222, USA
| | - Emily E Davey
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
| | - Cristina C DeMeo
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
| | | | - Lori Planco
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
| | - Jose M Velez
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
- Department of Biology, University at Albany—SUNY, Albany, NY 12222, USA
| | | | - Damian S Shin
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, USA
| | - John D Cleary
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
| | - J Andrew Berglund
- The RNA Institute, University at Albany—SUNY, Albany, NY 12222, USA
- Department of Biology, University at Albany—SUNY, Albany, NY 12222, USA
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Zhang G, Lai Z, Gu L, Xu K, Wang Z, Duan Y, Chen H, Zhang M, Zhang J, Zhao Z, Wang S. Delta Opioid Receptor Activation with Delta Opioid Peptide [d-Ala2, d-Leu5] Enkephalin Contributes to Synaptic Improvement in Rat Hippocampus against Global Ischemia. Cell Transplant 2021; 30:9636897211041585. [PMID: 34470528 PMCID: PMC8419564 DOI: 10.1177/09636897211041585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Global cerebral ischemia induced by cardiac arrest usually leads to poor neurological outcomes. Numerous studies have focused on ways to prevent ischemic damage in the brain, however clinical therapies are still limited. Our previous studies revealed that delta opioid receptor (DOR) activation with [d-Ala2, d-Leu5] enkephalin (DADLE), a DOR agonist, not only significantly promotes neuronal survival on day 3, but also improves spatial memory deficits on days 5-9 after ischemia. However, the neurological mechanism underlying DADLE-induced cognitive recovery remains unclear. This study first examined the changes in neuronal survival in the CA1 region at the advanced time point (day 7) after ischemia/reperfusion (I/R) injury and found a significant amelioration of damaged CA1 neurons in the rats treated with DADLE (2.5 nmol) when administered at the onset of reperfusion. The structure and function of CA1 neurons on days 3 and 7 post-ischemia showed significant improvements in both the density of the injured dendritic spines and the basic transmission of the impaired CA3-CA1 synapses following DADLE treatment. The molecular changes involved in DADLE-mediated synaptic modulation on days 3 and 7 post-ischemia implied the time-related differential regulation of PKCα-MARCKS on the dendritic spine structure and of BDNF- ERK1/2-synapsin I on synaptic function, in response to ischemic/reperfusion injury as well as to DADLE treatment. Importantly, all the beneficial effects of DADLE on ischemia-induced cellular, synaptic, and molecular deficits were eliminated by the DOR inhibitor naltrindole (2.5 nmol). Taken together, this study suggested that DOR activation-induced protective signaling pathways of PKCα-MARCKS involved in the synaptic morphology and BDNF-ERK-synapsin I in synaptic transmission may be engaged in the cognitive recovery in rats suffering from advanced cerebral ischemia.
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Affiliation(s)
- Guangming Zhang
- Department of Anesthesiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200336, China
| | - Zelin Lai
- Shanghai Key Laboratory of Brain Functional Genomics, Ministry of Education, School of Life Sciences, East China Normal University, Shanghai 200062, China
| | - Lingling Gu
- Shanghai Key Laboratory of Brain Functional Genomics, Ministry of Education, School of Life Sciences, East China Normal University, Shanghai 200062, China
| | - Kejia Xu
- Department of Anesthesiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200336, China
| | - Zhenlu Wang
- Shanghai Key Laboratory of Brain Functional Genomics, Ministry of Education, School of Life Sciences, East China Normal University, Shanghai 200062, China
| | - Yale Duan
- Shanghai Key Laboratory of Brain Functional Genomics, Ministry of Education, School of Life Sciences, East China Normal University, Shanghai 200062, China
| | - Huifen Chen
- Department of Clinical Laboratory, Shanghai First Maternity and Infant Hospital
| | - Min Zhang
- Tongji University School of Medicine, Shanghai 201204, China
| | - Jun Zhang
- Department of Clinical Laboratory, Shanghai First Maternity and Infant Hospital.,Tongji University School of Medicine, Shanghai 201204, China
| | - Zheng Zhao
- Shanghai Key Laboratory of Brain Functional Genomics, Ministry of Education, School of Life Sciences, East China Normal University, Shanghai 200062, China
| | - Shuyan Wang
- Department of Anesthesiology, Tongren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200336, China
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Heckman CA, Biswas T, Dimick DM, Cayer ML. Activated Protein Kinase C (PKC) Is Persistently Trafficked with Epidermal Growth Factor (EGF) Receptor. Biomolecules 2020; 10:E1288. [PMID: 32906765 PMCID: PMC7563713 DOI: 10.3390/biom10091288] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/02/2020] [Accepted: 09/05/2020] [Indexed: 12/22/2022] Open
Abstract
Protein kinase Cs (PKCs) are activated by lipids in the plasma membrane and bind to a scaffold assembled on the epidermal growth factor (EGF) receptor (EGFR). Understanding how this complex is routed is important, because this determines whether EGFR is degraded, terminating signaling. Here, cells were preincubated in EGF-tagged gold nanoparticles, then allowed to internalize them in the presence or absence of a phorbol ester PKC activator. PKC colocalized with EGF-tagged nanoparticles within 5 min and migrated with EGFR-bearing vesicles into the cell. Two conformations of PKC-epsilon were distinguished by different primary antibodies. One, thought to be enzymatically active, was on endosomes and displayed a binding site for antibody RR (R&D). The other, recognized by Genetex green (GG), was soluble, on actin-rich structures, and loosely bound to vesicles. During a 15-min chase, EGF-tagged nanoparticles entered large, perinuclear structures. In phorbol ester-treated cells, vesicles bearing EGF-tagged nanoparticles tended to enter this endocytic recycling compartment (ERC) without the GG form. The correlation coefficient between the GG (inactive) and RR conformations on vesicles was also lower. Thus, active PKC has a Charon-like function, ferrying vesicles to the ERC, and inactivation counteracts this function. The advantage conferred on cells by aggregating vesicles in the ERC is unclear.
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Affiliation(s)
- Carol A. Heckman
- Department of Biological Sciences, 217 Life Science Building, Bowling Green State University, Bowling Green, OH 43403, USA;
| | - Tania Biswas
- Department of Biological Sciences, 217 Life Science Building, Bowling Green State University, Bowling Green, OH 43403, USA;
| | - Douglas M. Dimick
- Department of Physics & Astronomy, 104 Overman Hall, Bowling Green State University, Bowling Green, OH 43403, USA;
| | - Marilyn L. Cayer
- Center for Microscopy & Microanalysis, 217 Life Science Building, Bowling Green State University, Bowling Green, OH 43403, USA;
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Arafiles JVV, Hirose H, Akishiba M, Tsuji S, Imanishi M, Futaki S. Stimulating Macropinocytosis for Intracellular Nucleic Acid and Protein Delivery: A Combined Strategy with Membrane-Lytic Peptides To Facilitate Endosomal Escape. Bioconjug Chem 2020; 31:547-553. [PMID: 32017537 DOI: 10.1021/acs.bioconjchem.0c00064] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Delivery of biomacromolecules via endocytic pathways requires the efficient accumulation of cargo molecules into endosomes, followed by their release to the cytosol. We propose a unique intracellular delivery strategy for bioactive molecules using a new potent macropinocytosis-inducing peptide derived from stromal-derived factor 1α (SN21). This peptide allowed extracellular materials to enter cells through the activation of macropinocytosis. To provide the ability to release internalized cargoes from endosomes, we conjugated SN21 with membrane-lytic peptides. The combination of a macropinocytosis-inducing peptide and a membrane-lytic peptide successfully delivered functional siRNA and proteins, which include antibodies, Cre recombinase, and an artificial transcription regulator protein having a transcription activator-like effector (TALE) motif. This study shows the feasibility of combining the physiological stimulation of macropinocytosis with the physicochemical disruption of endosomes as a strategy for intracellular delivery.
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Affiliation(s)
| | - Hisaaki Hirose
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Misao Akishiba
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Shogo Tsuji
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Miki Imanishi
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Shiroh Futaki
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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Low Electric Treatment activates Rho GTPase via Heat Shock Protein 90 and Protein Kinase C for Intracellular Delivery of siRNA. Sci Rep 2019; 9:4114. [PMID: 30858501 PMCID: PMC6412017 DOI: 10.1038/s41598-019-40904-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 01/28/2019] [Indexed: 11/08/2022] Open
Abstract
Low electric treatment (LET) promotes intracellular delivery of naked siRNA by altering cellular physiology. However, which signaling molecules and cellular events contribute to LET-mediated siRNA uptake are unclear. Here, we used isobaric tags in relative and absolute quantification (iTRAQ) proteomic analysis to identify changes in the levels of phosphorylated proteins that occur during cellular uptake of siRNA promoted by LET. iTRAQ analysis revealed that heat shock protein 90 (Hsp90)α and myristoylated alanine-rich C-kinase substrate (Marcks) were highly phosphorylated following LET of NIH 3T3 cells, but not untreated cells. Furthermore, the levels of phosphorylated Hsp90α and protein kinase C (PKC)γ were increased by LET both with siRNA and liposomes having various physicochemical properties used as model macromolecules, suggesting that PKCγ activated partly by Ca2+ influx as well as Hsp90 chaperone function were involved in LET-mediated cellular siRNA uptake. Furthermore, LET with siRNA induced activation of Rho GTPase via Hsp90 and PKC, which could contribute to cellular siRNA uptake accompanied by actin cytoskeleton remodeling. Collectively, our results suggested that LET-induced Rho GTPase activation via Hsp90 and PKC would participate in actin-dependent cellular uptake of siRNA.
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Singla B, Lin HP, Ghoshal P, Cherian-Shaw M, Csányi G. PKCδ stimulates macropinocytosis via activation of SSH1-cofilin pathway. Cell Signal 2018; 53:111-121. [PMID: 30261270 DOI: 10.1016/j.cellsig.2018.09.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 09/19/2018] [Accepted: 09/23/2018] [Indexed: 12/13/2022]
Abstract
Macropinocytosis is an actin-dependent endocytic mechanism mediating internalization of extracellular fluid and associated solutes into cells. The present study was designed to identify the specific protein kinase C (PKC) isoform(s) and downstream effectors regulating actin dynamics during macropinocytosis. We utilized various cellular and molecular biology techniques, pharmacological inhibitors and genetically modified mice to study the signaling mechanisms mediating macropinocytosis in macrophages. The qRT-PCR experiments identified PKCδ as the predominant PKC isoform in macrophages. Scanning electron microscopy and flow cytometry analysis of FITC-dextran internalization demonstrated the functional role of PKCδ in phorbol ester- and hepatocyte growth factor (HGF)-induced macropinocytosis. Western blot analysis demonstrated that phorbol ester and HGF stimulate activation of slingshot phosphatase homolog 1 (SSH1) and induce cofilin Ser-3 dephosphorylation via PKCδ in macrophages. Silencing of SSH1 inhibited cofilin dephosphorylation and macropinocytosis stimulation. Interestingly, we also found that incubation of macrophages with BMS-5, a potent inhibitor of LIM kinase, does not stimulate macropinocytosis. In conclusion, the findings of the present study demonstrate a previously unidentified mechanism by which PKCδ via activation of SSH1 and cofilin dephosphorylation stimulates membrane ruffle formation and macropinocytosis. The results of the present study may contribute to a better understanding of the regulatory mechanisms during macrophage macropinocytosis.
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Affiliation(s)
- Bhupesh Singla
- Vascular Biology Center, 1460 Laney Walker Blvd., Augusta University, Medical College of Georgia, Augusta, GA 30912, USA
| | - Hui-Ping Lin
- Vascular Biology Center, 1460 Laney Walker Blvd., Augusta University, Medical College of Georgia, Augusta, GA 30912, USA
| | - Pushpankur Ghoshal
- Vascular Biology Center, 1460 Laney Walker Blvd., Augusta University, Medical College of Georgia, Augusta, GA 30912, USA
| | - Mary Cherian-Shaw
- Vascular Biology Center, 1460 Laney Walker Blvd., Augusta University, Medical College of Georgia, Augusta, GA 30912, USA
| | - Gábor Csányi
- Vascular Biology Center, 1460 Laney Walker Blvd., Augusta University, Medical College of Georgia, Augusta, GA 30912, USA; Department of Pharmacology and Toxicology, 1460 Laney Walker Blvd., Augusta University, Medical College of Georgia, Augusta, GA 30912, USA.
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Wan L, Xu K, Chen Z, Tang B, Jiang H. Roles of Post-translational Modifications in Spinocerebellar Ataxias. Front Cell Neurosci 2018; 12:290. [PMID: 30283301 PMCID: PMC6156280 DOI: 10.3389/fncel.2018.00290] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 08/13/2018] [Indexed: 12/17/2022] Open
Abstract
Post-translational modifications (PTMs), including phosphorylation, acetylation, ubiquitination, SUMOylation, etc., of proteins can modulate protein properties such as intracellular distribution, activity, stability, aggregation, and interactions. Therefore, PTMs are vital regulatory mechanisms for multiple cellular processes. Spinocerebellar ataxias (SCAs) are hereditary, heterogeneous, neurodegenerative diseases for which the primary manifestation involves ataxia. Because the pathogenesis of most SCAs is correlated with mutant proteins directly or indirectly, the PTMs of disease-related proteins might functionally affect SCA development and represent potential therapeutic interventions. Here, we review multiple PTMs related to disease-causing proteins in SCAs pathogenesis and their effects. Furthermore, we discuss these PTMs as potential targets for treating SCAs and describe translational therapies targeting PTMs that have been published.
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Affiliation(s)
- Linlin Wan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Keqin Xu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Zhao Chen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Diseases, Central South University, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
- Laboratory of Medical Genetics, Central South University, Changsha, China
- Parkinson’s Disease Center of Beijing Institute for Brain Disorders, Beijing, China
- Collaborative Innovation Center for Brain Science, Shanghai, China
- Collaborative Innovation Center for Genetics and Development, Shanghai, China
| | - Hong Jiang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Diseases, Central South University, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
- Laboratory of Medical Genetics, Central South University, Changsha, China
- Department of Neurology, Xinjiang Medical University, Ürümqi, China
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8
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Singla B, Ghoshal P, Lin H, Wei Q, Dong Z, Csányi G. PKCδ-Mediated Nox2 Activation Promotes Fluid-Phase Pinocytosis of Antigens by Immature Dendritic Cells. Front Immunol 2018; 9:537. [PMID: 29632528 PMCID: PMC5879126 DOI: 10.3389/fimmu.2018.00537] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/02/2018] [Indexed: 12/31/2022] Open
Abstract
Aims Macropinocytosis is a major endocytic pathway by which dendritic cells (DCs) internalize antigens in the periphery. Despite the importance of DCs in the initiation and control of adaptive immune responses, the signaling mechanisms mediating DC macropinocytosis of antigens remain largely unknown. The goal of the present study was to investigate whether protein kinase C (PKC) is involved in stimulation of DC macropinocytosis and, if so, to identify the specific PKC isoform(s) and downstream signaling mechanisms involved. Methods Various cellular, molecular and immunological techniques, pharmacological approaches and genetic knockout mice were utilized to investigate the signaling mechanisms mediating DC macropinocytosis. Results Confocal laser scanning microscopy confirmed that DCs internalize fluorescent antigens (ovalbumin) using macropinocytosis. Pharmacological blockade of classical and novel PKC isoforms using calphostin C abolished both phorbol ester- and hepatocyte growth factor-induced antigen macropinocytosis in DCs. The qRT-PCR experiments identified PKCδ as the dominant PKC isoform in DCs. Genetic studies demonstrated the functional role of PKCδ in DC macropinocytosis of antigens, their subsequent maturation, and secretion of various T-cell stimulatory cytokines, including IL-1α, TNF-α and IFN-β. Additional mechanistic studies identified NADPH oxidase 2 (Nox2) and intracellular superoxide anion as important players in DC macropinocytosis of antigens downstream of PKCδ activation. Conclusion The findings of the present study demonstrate a novel mechanism by which PKCδ activation via stimulation of Nox2 activity and downstream redox signaling promotes DC macropinocytosis of antigens. PKCδ/Nox2-mediated antigen macropinocytosis stimulates maturation of DCs and secretion of T-cell stimulatory cytokines. These findings may contribute to a better understanding of the regulatory mechanisms in DC macropinocytosis and downstream regulation of T-cell-mediated responses.
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Affiliation(s)
- Bhupesh Singla
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Pushpankur Ghoshal
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Huiping Lin
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Qingqing Wei
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Zheng Dong
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Gábor Csányi
- Vascular Biology Center, Medical College of Georgia, Augusta University, Augusta, GA, United States.,Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, United States
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Zeineddine R, Yerbury JJ. The role of macropinocytosis in the propagation of protein aggregation associated with neurodegenerative diseases. Front Physiol 2015; 6:277. [PMID: 26528186 PMCID: PMC4607857 DOI: 10.3389/fphys.2015.00277] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 09/18/2015] [Indexed: 12/12/2022] Open
Abstract
With the onset of the rapidly aging population, the impact of age related neurodegenerative diseases is becoming a predominant health and economic concern. Neurodegenerative diseases such as Alzheimer's disease, Creutzfeldt-Jakob disease (CJD), Parkinson's disease, Huntington's disease, frontotemporal dementia (FTD), and amyotrophic lateral sclerosis (ALS) result from the loss of a specific subsets of neurons, which is closely associated with accumulation and deposition of specific protein aggregates. Protein aggregation, or fibril formation, is a well-studied phenomenon that occurs in a nucleation-dependent growth reaction. Recently, there has been a swell of literature implicating protein aggregation and its ability to propagate cell-to-cell in the rapid progression of these diseases. In order for protein aggregation to be kindled in recipient cells it is a requisite that aggregates must be able to be released from one cell and then taken up by others. In this article we will explore the relationship between protein aggregates, their propagation and the role of macropinocytosis in their uptake. We highlight the ability of neurons to undergo stimulated macropinocytosis and identify potential therapeutic targets.
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Affiliation(s)
- Rafaa Zeineddine
- Illawarra Health and Medical Research Institute, University of Wollongong Wollongong, NSW, Australia ; Faculty of Science, Medicine and Health, School of Biological Sciences, University of Wollongong Wollongong, NSW, Australia
| | - Justin J Yerbury
- Illawarra Health and Medical Research Institute, University of Wollongong Wollongong, NSW, Australia ; Faculty of Science, Medicine and Health, School of Biological Sciences, University of Wollongong Wollongong, NSW, Australia
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10
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Brudvig JJ, Weimer JM. X MARCKS the spot: myristoylated alanine-rich C kinase substrate in neuronal function and disease. Front Cell Neurosci 2015; 9:407. [PMID: 26528135 PMCID: PMC4602126 DOI: 10.3389/fncel.2015.00407] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 09/25/2015] [Indexed: 11/18/2022] Open
Abstract
Intracellular protein-protein interactions are dynamic events requiring tightly regulated spatial and temporal checkpoints. But how are these spatial and temporal cues integrated to produce highly specific molecular response patterns? A helpful analogy to this process is that of a cellular map, one based on the fleeting localization and activity of various coordinating proteins that direct a wide array of interactions between key molecules. One such protein, myristoylated alanine-rich C-kinase substrate (MARCKS) has recently emerged as an important component of this cellular map, governing a wide variety of protein interactions in every cell type within the brain. In addition to its well-documented interactions with the actin cytoskeleton, MARCKS has been found to interact with a number of other proteins involved in processes ranging from intracellular signaling to process outgrowth. Here, we will explore these diverse interactions and their role in an array of brain-specific functions that have important implications for many neurological conditions.
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Affiliation(s)
- Jon J Brudvig
- Children's Health Research Center, Sanford Research Sioux Falls, SD, USA ; Basic Biomedical Sciences, University of South Dakota Vermillion, SD, USA
| | - Jill M Weimer
- Children's Health Research Center, Sanford Research Sioux Falls, SD, USA ; Department of Pediatrics, Sanford School of Medicine, University of South Dakota Vermillion, SD, USA
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11
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Yoshida S, Gaeta I, Pacitto R, Krienke L, Alge O, Gregorka B, Swanson JA. Differential signaling during macropinocytosis in response to M-CSF and PMA in macrophages. Front Physiol 2015; 6:8. [PMID: 25688212 PMCID: PMC4310286 DOI: 10.3389/fphys.2015.00008] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 01/08/2015] [Indexed: 01/30/2023] Open
Abstract
The cellular movements that construct a macropinosome have a corresponding sequence of chemical transitions in the cup-shaped region of plasma membrane that becomes the macropinosome. To determine the relative positions of type I phosphatidylinositol 3-kinase (PI3K) and phospholipase C (PLC) in this pathway, we analyzed macropinocytosis in macrophages stimulated by the growth factor macrophage-colony-stimulating factor (M-CSF) and by the diacylglycerol (DAG) analog phorbol 12-myristate 13-acetate (PMA). In cells stimulated with M-CSF, microscopic imaging of fluorescent probes for intracellular lipids indicated that the PI3K product phosphatidylinositol (3,4,5)-trisphosphate (PIP3) appeared in cups just prior to DAG. We then tested the hypothesis that PMA and DAG function after PI3K and prior to Ras and protein kinase C (PKC) during macropinosome formation in macrophages. Although the PI3K target Akt was activated by M-CSF, the Akt inhibitor MK-2206 did not inhibit macropinocytosis. The phospholipase C (PLC) inhibitor U73122 blocked macropinocytosis by M-CSF but not PMA. Macropinocytosis in response to M-CSF and PMA was inhibited by the Ras inhibitor farnesyl thiosalicylate (FTS), by the PKC inhibitor Calphostin C and by the broad specificity inhibitor rottlerin. These studies support a model in which M-CSF stimulates PI3K in macropinocytic cups, and the resulting increase in PIP3 activates PLC, which in turn generates DAG necessary for activation of PKC, Ras and the late stages of macropinosome closure.
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Affiliation(s)
- Sei Yoshida
- Department of Microbiology and Immunology, University of Michigan Medical School Ann Arbor, MI, USA
| | - Isabella Gaeta
- Department of Microbiology and Immunology, University of Michigan Medical School Ann Arbor, MI, USA
| | - Regina Pacitto
- Department of Microbiology and Immunology, University of Michigan Medical School Ann Arbor, MI, USA
| | - Lydia Krienke
- Department of Microbiology and Immunology, University of Michigan Medical School Ann Arbor, MI, USA
| | - Olivia Alge
- Department of Microbiology and Immunology, University of Michigan Medical School Ann Arbor, MI, USA
| | - Brian Gregorka
- Department of Microbiology and Immunology, University of Michigan Medical School Ann Arbor, MI, USA
| | - Joel A Swanson
- Department of Microbiology and Immunology, University of Michigan Medical School Ann Arbor, MI, USA
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