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Mesa H, Zhang EY, Wang Y, Zhang Q. Human neurons lacking amyloid precursor protein exhibit cholesterol-associated developmental and presynaptic deficits. J Cell Physiol 2024; 239:e30999. [PMID: 36966431 DOI: 10.1002/jcp.30999] [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: 12/28/2022] [Revised: 01/29/2023] [Accepted: 03/06/2023] [Indexed: 03/27/2023]
Abstract
Amyloid precursor protein (APP) produces aggregable β-amyloid peptides and its mutations are associated with familial Alzheimer's disease (AD), which makes it one of the most studied proteins. However, APP's role in the human brain remains unclear despite years of investigation. One problem is that most studies on APP have been carried out in cell lines or model organisms, which are physiologically different from human neurons in the brain. Recently, human-induced neurons (hiNs) derived from induced pluripotent stem cells (iPSCs) provide a practical platform for studying the human brain in vitro. Here, we generated APP-null iPSCs using CRISPR/Cas9 genome editing technology and differentiate them into matured human neurons with functional synapses using a two-step procedure. During hiN differentiation and maturation, APP-null cells exhibited less neurite growth and reduced synaptogenesis in serum-free but not serum-containing media. We have found that cholesterol (Chol) remedies those developmental defects in APP-null cells, consistent with Chol's role in neurodevelopment and synaptogenesis. The phenotypic rescue was also achieved by coculturing those cells with wild-type mouse astrocytes, suggesting that APP's developmental role is likely astrocytic. Next, we examined matured hiNs using patch-clamp recording and detected reduced synaptic transmission in APP-null cells. This change was largely due to decreased synaptic vesicle (SV) release and retrieval, which was confirmed by live-cell imaging using two SV-specific fluorescent reporters. Adding Chol shortly before stimulation mitigated the SV deficits in APP-null iNs, indicating that APP facilitates presynaptic membrane Chol turnover during the SV exo-/endocytosis cycle. Taken together, our study in hiNs supports the notion that APP contributes to neurodevelopment, synaptogenesis, and neurotransmission via maintaining brain Chol homeostasis. Given the vital role of Chol in the central nervous system, the functional connection between APP and Chol bears important implications in the pathogenesis of AD.
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Affiliation(s)
- Haylee Mesa
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, Florida, USA
| | - Elaine Y Zhang
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, Florida, USA
- Brentwood High School, Brentwood, Tennessee, USA
| | - Yingcai Wang
- Department of Biomedical Sciences, Florida Atlantic University, Boca Raton, Florida, USA
| | - Qi Zhang
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, Florida, USA
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida, USA
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Chagraoui A, Anouar Y, De Deurwaerdere P, Arias HR. To what extent may aminochrome increase the vulnerability of dopaminergic neurons in the context of Parkinson's disease. Int J Biochem Cell Biol 2024; 168:106528. [PMID: 38246261 DOI: 10.1016/j.biocel.2024.106528] [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: 11/19/2023] [Revised: 01/11/2024] [Accepted: 01/16/2024] [Indexed: 01/23/2024]
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder that progresses over time and is characterized by preferential reduction of dopaminergic neurons in the substantia nigra. Although the precise mechanisms leading to cell death in neurodegenerative disorders, such as PD, are not fully understood, it is widely accepted that increased oxidative stress may be a prevalent factor contributing to the deterioration of the nigrostriatal dopaminergic fibers in such conditions. Aminochrome, generated from dopamine (DA) metabolism, plays an important role in multiple pathogenic mechanisms associated with PD. Its capacity to induce a gradual reduction in dopaminergic neurons is due to its endogenous neurotoxicity. The formation of aminochrome results in the production of various reactive oxygen species (ROS), including pro-inflammatory factors, superoxide, nitric oxide, and hydroxyl radicals. This, in turn, causes loss of dopaminergic neurons, reducing DA uptake, and reduced numbers and shortened dendrites. Notably, o-quinones, which are more cytotoxic, arise from the oxidation of DA and possess a higher capacity to impede cellular defense mechanisms, thereby resulting in the death of neuronal cells. Aminochrome potentially contributes to the pathophysiology of PD by forming adducts with various proteins. All of the aforementioned effects suggest that aminochrome may play a crucial role in the pathophysiology of PD. Thus, aminochrome may serve as a more relevant preclinical model for PD, facilitating a better understanding of its pathophysiological processes and identification of novel therapeutic strategies aimed at preventing or slowing disease progression.
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Affiliation(s)
- Abdeslam Chagraoui
- Department of Medical Biochemistry, Rouen University Hospital, CHU de Rouen, France; UNIROUEN, Inserm U1239, Neuroendocrine, Endocrine and Germinal Differentiation and Communication (NorDiC), Rouen Normandie University, 76000 Mont-Saint-Aignan, France.
| | - Youssef Anouar
- UNIROUEN, Inserm U1239, Neuroendocrine, Endocrine and Germinal Differentiation and Communication (NorDiC), Rouen Normandie University, 76000 Mont-Saint-Aignan, France
| | - Philippe De Deurwaerdere
- Centre National de la Recherche Scientifique, Institut des Neurosciences Intégratives et Cognitives d'Aquitaine, UMR, 5287, Bordeaux, France
| | - Hugo R Arias
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, OK, USA
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Iacovitti L. On the Road from Phenotypic Plasticity to Stem Cell Therapy. J Neurosci 2021; 41:5331-5337. [PMID: 33958488 PMCID: PMC8221603 DOI: 10.1523/jneurosci.0340-21.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/18/2021] [Accepted: 04/27/2021] [Indexed: 11/21/2022] Open
Abstract
In 1981, I published a paper in the first issue of The Journal of Neuroscience with my postdoctoral mentor, Richard Bunge. At that time, the long-standing belief that each neuron expressed only one neurotransmitter, known as Dale's Principle (Dale, 1935), was being hotly debated following a report by French embryologist Nicole Le Douarin showing that neural crest cells destined for one transmitter phenotype could express characteristics of another if transplanted to alternate sites in the developing embryo (Le Douarin, 1980). In the Bunge laboratory, we were able to more directly test the question of phenotypic plasticity in the controlled environment of the tissue culture dish. Thus, in our paper, we grew autonomic catecholaminergic neurons in culture under conditions which promoted the acquisition of cholinergic traits and showed that cells did not abandon their inherited phenotype to adopt a new one but instead were capable of dual transmitter expression. In this Progressions article, I detail the path that led to these findings and how this study impacted the direction I followed for the next 40 years. This is my journey from phenotypic plasticity to the promise of a stem cell therapy.
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Affiliation(s)
- Lorraine Iacovitti
- Department of Neuroscience, Director, Jefferson Stem Cell and Regenerative Neuroscience Center, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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Umek N, Geršak B, Vintar N, Šoštarič M, Mavri J. Dopamine Autoxidation Is Controlled by Acidic pH. Front Mol Neurosci 2018; 11:467. [PMID: 30618616 PMCID: PMC6305604 DOI: 10.3389/fnmol.2018.00467] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 12/03/2018] [Indexed: 11/16/2022] Open
Abstract
We studied the reaction mechanism of dopamine autoxidation using quantum chemical methods. Unlike other biogenic amines important in the central nervous system, dopamine and noradrenaline are capable of undergoing a non-enzymatic autoxidative reaction giving rise to a superoxide anion that further decomposes to reactive oxygen species. The reaction in question, which takes place in an aqueous solution, is as such not limited to the mitochondrial membrane where scavenging enzymes such as catalase and superoxide dismutase are located. With the experimental rate constant of 0.147 s−1, the dopamine autoxidation reaction is comparably as fast as the monoamine oxidase B catalyzed dopamine decomposition with a rate constant of 1 s−1. By using quantum chemical calculations, we demonstrated that the rate-limiting step is the formation of a hydroxide ion from a water molecule, which attacks the amino group that enters intramolecular Michael addition, giving rise to a pharmacologically inert aminochrome. We have shown that for dopamine stability on a time scale of days, it is essential that the pH value of the synaptic vesicle interior is acidic. The pathophysiologic correlates of the results are discussed in the context of Parkinson's disease as well as the pathology caused by long-term amphetamine and cocaine administration.
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Affiliation(s)
- Nejc Umek
- Department of Anesthesiology and Surgical Intensive Therapy, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Institute of Anatomy, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Blaž Geršak
- Department of Anesthesiology and Surgical Intensive Therapy, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Neli Vintar
- Department of Anesthesiology and Surgical Intensive Therapy, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Department of Anesthesiology and Reanimatology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Maja Šoštarič
- Department of Anesthesiology and Surgical Intensive Therapy, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Department of Anesthesiology and Reanimatology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Janez Mavri
- National Institute of Chemistry, Ljubljana, Slovenia
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Lazarenko RM, DelBove CE, Strothman CE, Zhang Q. Ammonium chloride alters neuronal excitability and synaptic vesicle release. Sci Rep 2017; 7:5061. [PMID: 28698583 PMCID: PMC5505971 DOI: 10.1038/s41598-017-05338-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 06/12/2017] [Indexed: 01/28/2023] Open
Abstract
Genetically encoded pH-sensors are widely used in studying cell membrane trafficking and membrane protein turnover because they render exo-/endocytosis-associated pH changes to fluorescent signals. For imaging and analysis purposes, high concentration ammonium chloride is routinely used to alkalize intracellular membrane compartments under the assumption that it does not cause long-term effects on cellular processes being studied like neurotransmission. However, pathological studies about hyperammonemia have shown that ammonium is toxic to brain cells especially astrocytes and neurons. Here, we focus on ammonium’s physiological impacts on neurons including membrane potential, cytosolic Ca2+ and synaptic vesicles. We have found that extracellularly applied ammonium chloride as low as 5 mM causes intracellular Ca2+-increase and a reduction of vesicle release even after washout. The often-used 50 mM ammonium chloride causes more extensive and persistent changes, including membrane depolarization, prolonged elevation of intracellular Ca2+ and diminution of releasable synaptic vesicles. Our findings not only help to bridge the discrepancies in previous studies about synaptic vesicle release using those pH-sensors or other vesicle specific reporters, but also suggest an intriguing relationship between intracellular pH and neurotransmission.
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Affiliation(s)
- Roman M Lazarenko
- Department of Pharmacology, Vanderbilt University, 23rd Avenue South at Pierce Street, Nashville, TN, 37232, USA
| | - Claire E DelBove
- Department of Pharmacology, Vanderbilt University, 23rd Avenue South at Pierce Street, Nashville, TN, 37232, USA
| | - Claire E Strothman
- Department of Pharmacology, Vanderbilt University, 23rd Avenue South at Pierce Street, Nashville, TN, 37232, USA
| | - Qi Zhang
- Department of Pharmacology, Vanderbilt University, 23rd Avenue South at Pierce Street, Nashville, TN, 37232, USA.
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