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Dashkova AS, Kovalev VI, Chaplygina AV, Zhdanova DY, Bobkova NV. Unique Properties of Synaptosomes and Prospects for Their Use for the Treatment of Alzheimer's Disease. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:1031-1044. [PMID: 38981699 DOI: 10.1134/s0006297924060051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 03/21/2024] [Accepted: 03/23/2024] [Indexed: 07/11/2024]
Abstract
Alzheimer's disease (AD) is a severe neurodegenerative condition affecting millions worldwide. Prevalence of AD correlates with increased life expectancy and aging population in the developed countries. Considering that AD is a multifactorial disease involving various pathological processes such as synaptic dysfunction, neuroinflammation, oxidative stress, and improper protein folding, a comprehensive approach targeting multiple pathways may prove effective in slowing the disease progression. Cellular therapy and its further development in the form of cell vesicle and particularly mitochondrial transplantation represent promising approaches for treating neurodegeneration. The use of synaptosomes, due to uniqueness of their contents, could mark a new stage in the development of comprehensive therapies for neurodegenerative diseases, particularly AD. Synaptosomes contain unique memory mitochondria, which differ not only in size but also in functionality compared to the mitochondria in the neuronal soma. These synaptosomal mitochondria actively participate in cellular communication and signal transmission within synapses. Synaptosomes also contain other elements such as their own protein synthesis machinery, synaptic vesicles with neurotransmitters, synaptic adhesion molecules, and microRNAs - all crucial for synaptic transmission and, consequently, cognitive processes. Complex molecular ensemble ensures maintenance of the synaptic autonomy of mitochondria. Additionally, synaptosomes, with their affinity for neurons, can serve as an optimal platform for targeted drug delivery to nerve cells. This review discusses unique composition of synaptosomes, their capabilities and advantages, as well as limitations of their suggested use as therapeutic agents for treating neurodegenerative pathologies, particularly AD.
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Affiliation(s)
- Alla S Dashkova
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Vladimir I Kovalev
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| | - Alina V Chaplygina
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Daria Yu Zhdanova
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Natalia V Bobkova
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
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Giuditta A, Zucconi GG, Sadile A. Brain Metabolic DNA: A Long Story and Some Conclusions. Mol Neurobiol 2022; 60:228-234. [PMID: 36251232 DOI: 10.1007/s12035-022-03030-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 09/09/2022] [Indexed: 11/26/2022]
Abstract
We have previously outlined the main properties of brain metabolic DNA (BMD) and its involvement in circadian oscillations, learning, and post-trial sleep. The presence of BMD in certain subcellular fractions and their behavior in cesium gradients have suggested that BMD originates from cytoplasmic reverse transcription and subsequently acquires a double-stranded configuration. More recently, it has been reported that some DNA sequences of cytoplasmic BMD in learning mice are different from that of the control animals. Furthermore, BMD is located in vicinity of the genes involved in different modifications of synaptic activity, suggesting that BMD may contribute to the brain's response to the changing environment. The present review outlines recent data with a special emphasis on reverse transcription of BMD that may recapitulate the molecular events at the time of the "RNA world" by activating mitochondrial telomerase and generating RNA templates from mitochondrial transcripts. The latter unexpected role of mitochondria is likely to promote a better understanding of mitochondrial contribution to cellular interactions and eukaryotic evolution. An initial step regards the role of human mitochondria in embryonic BMD synthesis, which is exclusively of maternal origin. In addition, mitochondrial transcripts involved in reverse transcription of BMD might possibly reveal unexpected features elucidating mitochondrial involvement in cancer events and neurodegenerative disorders.
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Affiliation(s)
- Antonio Giuditta
- Accademia Di Scienze Fisiche E Matematiche, Via Mezzocannone 8, 80134, Napoli, Italy.
| | | | - Adolfo Sadile
- Dept Experimental Medicine, Medical School, University Campania "L. Vanvitelli", Via S. Andrea delle Dame 7, 80138, Naples, Italy
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Giuditta A, Grassi Zucconi G, Sadile A. Brain metabolic DNA: recent evidence for a mitochondrial connection. Rev Neurosci 2020; 32:/j/revneuro.ahead-of-print/revneuro-2020-0050/revneuro-2020-0050.xml. [PMID: 32866135 DOI: 10.1515/revneuro-2020-0050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 07/18/2020] [Indexed: 02/24/2024]
Abstract
This review highlights recent data concerning the synthesis of brain metabolic DNA (BMD) by cytoplasmic reverse transcription and the prompt acquisition of the double-stranded configuration that allows its partial transfer to nuclei. BMD prevails in the mitochondrial fraction and is present in presynaptic regions and astroglial processes where it undergoes a turnover lasting a few weeks. Additional data demonstrate that BMD sequences are modified by learning, thus indicating that the modified synaptic activity allowing proper brain responses is encoded in learning BMD. In addition, several converging observations regarding the origin of BMD strongly suggest that BMD is reverse transcribed by mitochondrial telomerase.
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Affiliation(s)
- Antonio Giuditta
- Accademia di Scienze Fisiche e Matematiche, Via Mezzocannone 8, Naples, I-80134,Italy
| | | | - Adolfo Sadile
- Department of Experimental Medicine, L. Vanvitelli Medical School, University Campania, Via S. Andrea delle dame 7, Naples, I-80138,Italy
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Giuditta A, Casalino J. Sequences of Reverse Transcribed Brain DNA Are Modified by Learning. Front Mol Neurosci 2020; 13:57. [PMID: 32410960 PMCID: PMC7199793 DOI: 10.3389/fnmol.2020.00057] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 03/17/2020] [Indexed: 11/13/2022] Open
Abstract
Brain metabolic DNA (BMD) is continuously synthesized by reverse transcription in presynaptic synaptosomes and astroglia, and is partly transferred to nuclei after acquiring the double stranded configuration. Synthesis and turnover of BMD are markedly dependent on brain activity, as shown by circadian oscillations, environmental enrichment and impoverishment, and a variety of learning protocols. In rodents learning a two-way active avoidance task, BMD synthesis doubles, thus raising the possibility that sequences of learning BMD may differ from control BMD. The hypothesis has now been examined by sequencing cytoplasmic BMD. The present data indicate that most high-quality mapped BMD fragments hosting more than seven sequences are present in all mice. Three of them are exclusively present in learning BMD and four in control BMD. In addition, the annotated genes closest to them are mostly involved in modulating synaptic activity. The data support the conclusion that learning BMD sequences encode brain responses to the modified environment.
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Affiliation(s)
| | - Joyce Casalino
- Biology Department, Federico II University, Naples, Italy
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Prisco M, Casalino J, Cefaliello C, Giuditta A. Brain Metabolic DNA Is Reverse Transcribed in Cytoplasm: Evidence by Immunofluorescence Analysis. Mol Neurobiol 2019; 56:6770-6776. [PMID: 30919215 DOI: 10.1007/s12035-019-1569-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/18/2019] [Indexed: 10/27/2022]
Abstract
In a previous study (Mol Neurobiol 55:7476-7486, 2017), newly synthesized brain metabolic DNA (BMD) from rat subcellular fractions has been shown to behave as a DNA-RNA hybrid when analyzed in cesium gradients at early [3H] thymidine incorporation times but to assume the double-stranded configuration at later times. Conversely, BMD from purified nuclei displayed the dsDNA configuration even at early incorporation times. The results were interpreted to support the BMD origin by reverse transcription in the cytoplasm and its later acquisition of the double-stranded configuration before the partial transfer to the nuclei. This interpretation has now been confirmed by immunofluorescence analyses of newly synthesized BrdU-labeled BMD from the mouse brain that demonstrates its cytoplasmic localization and colocalization with DNA-RNA hybrids. In addition, BrdU-labeled BMD has been shown to colocalize with astroglial anti-GFAP antibodies and with presynaptic anti-synaptophysin antibodies.
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Affiliation(s)
- Marina Prisco
- Biology Department, University of Naples Federico II, Complesso Universitario Monte Sant'Angelo, Via Cinthia, 80126, Naples, Italy
| | - Joyce Casalino
- Biology Department, University of Naples Federico II, Complesso Universitario Monte Sant'Angelo, Via Cinthia, 80126, Naples, Italy
| | - Carolina Cefaliello
- Department of Neurology, University of Massachusetts Medical School, Albert Sherman Center 6-1008, 368 Plantation St., Worcester, MA, 01605, USA
| | - Antonio Giuditta
- Accademia di Scienze Fisiche e Matematiche, Via Mezzocannone 8, 80134, Naples, Italy.
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Cefaliello C, Prisco M, Crispino M, Giuditta A. DNA in Squid Synaptosomes. Mol Neurobiol 2018; 56:56-60. [PMID: 29675577 DOI: 10.1007/s12035-018-1071-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 04/09/2018] [Indexed: 11/26/2022]
Abstract
The synthesis of brain metabolic DNA (BMD) is modulated by learning and circadian oscillations and is not involved in cell division or DNA repair. Data from rats have highlighted its prevalent association with the mitochondrial fraction and its lack of identity with mtDNA. These features suggested that BMD could be localized in synaptosomes that are the major contaminants of brain mitochondrial fractions. The hypothesis has been examined by immunochemical analyses of the large synaptosomes of squid optic lobes that are readily prepared and identified. Optic lobe slices were incubated with 5-bromo-2-deoxyuridine (BrdU) and the isolated synaptosomal fraction was exposed to the green fluorescent anti-BrdU antibody. This procedure revealed that newly synthesized BrdU-labeled BMD is present in a significant percent of the large synaptosomes derived from the nerve terminals of retinal photoreceptor neurons and in synaptosomal bodies of smaller size. Synaptosomal BMD synthesis was strongly inhibited by actinomycin D. In addition, treatment of the synaptosomal fraction with Hoechst 33258, a blue fluorescent dye specific for dsDNA, indicated that native DNA was present in all synaptosomes. The possible role of synaptic BMD is briefly discussed.
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Affiliation(s)
- Carolina Cefaliello
- Department of Biology, University of Naples Federico II, Via Cinthia, 80126, Naples, Italy
- Department of Neurology, University of Massachusetts Medical School, Albert Sherman Center 6-1008, 368 Plantation St., Worcester, MA, 01605, USA
| | - Marina Prisco
- Department of Biology, University of Naples Federico II, Via Cinthia, 80126, Naples, Italy
| | - Marianna Crispino
- Department of Biology, University of Naples Federico II, Via Cinthia, 80126, Naples, Italy
| | - Antonio Giuditta
- Department of Biology, University of Naples Federico II, Via Cinthia, 80126, Naples, Italy.
- Accademia di Scienze Fisiche e Matematiche, Via Mezzocannone 8, 80134, Naples, Italy.
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