1
|
Gould R, Brady S. Identifying mRNAs Residing in Myelinating Oligodendrocyte Processes as a Basis for Understanding Internode Autonomy. Life (Basel) 2023; 13:life13040945. [PMID: 37109474 PMCID: PMC10142070 DOI: 10.3390/life13040945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/28/2023] [Accepted: 03/31/2023] [Indexed: 04/07/2023] Open
Abstract
In elaborating and maintaining myelin sheaths on multiple axons/segments, oligodendrocytes distribute translation of some proteins, including myelin basic protein (MBP), to sites of myelin sheath assembly, or MSAS. As mRNAs located at these sites are selectively trapped in myelin vesicles during tissue homogenization, we performed a screen to identify some of these mRNAs. To confirm locations, we used real-time quantitative polymerase chain reaction (RT-qPCR), to measure mRNA levels in myelin (M) and ‘non-myelin’ pellet (P) fractions, and found that five (LPAR1, TRP53INP2, TRAK2, TPPP, and SH3GL3) of thirteen mRNAs were highly enriched in myelin (M/P), suggesting residences in MSAS. Because expression by other cell-types will increase p-values, some MSAS mRNAs might be missed. To identify non-oligodendrocyte expression, we turned to several on-line resources. Although neurons express TRP53INP2, TRAK2 and TPPP mRNAs, these expressions did not invalidate recognitions as MSAS mRNAs. However, neuronal expression likely prevented recognition of KIF1A and MAPK8IP1 mRNAs as MSAS residents and ependymal cell expression likely prevented APOD mRNA assignment to MSAS. Complementary in situ hybridization (ISH) is recommended to confirm residences of mRNAs in MSAS. As both proteins and lipids are synthesized in MSAS, understanding myelination should not only include efforts to identify proteins synthesized in MSAS, but also the lipids.
Collapse
Affiliation(s)
- Robert Gould
- Whitman Research Center, Marine Biology Laboratory, Woods Hole, MA 02543, USA
| | - Scott Brady
- Departments of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
| |
Collapse
|
2
|
Dong R, Li X, Lai KO. Activity and Function of the PRMT8 Protein Arginine Methyltransferase in Neurons. Life (Basel) 2021; 11:life11111132. [PMID: 34833008 PMCID: PMC8621972 DOI: 10.3390/life11111132] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/20/2021] [Accepted: 10/20/2021] [Indexed: 12/13/2022] Open
Abstract
Among the nine mammalian protein arginine methyltransferases (PRMTs), PRMT8 is unusual because it has restricted expression in the nervous system and is the only membrane-bound PRMT. Emerging studies have demonstrated that this enzyme plays multifaceted roles in diverse processes in neurons. Here we will summarize the unique structural features of PRMT8 and describe how it participates in various neuronal functions such as dendritic growth, synapse maturation, and synaptic plasticity. Recent evidence suggesting the potential role of PRMT8 function in neurological diseases will also be discussed.
Collapse
|
3
|
Gilloteaux J, Subramanian K, Solomon N, Nicaise C. The leptin receptor mutation of the obese Zucker rat causes sciatic nerve demyelination with a centripetal pattern defect. Ultrastruct Pathol 2018; 42:377-408. [PMID: 30339059 DOI: 10.1080/01913123.2018.1522405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Young male Zucker rats with a leptin receptor mutation are obese, have a non-insulin-dependent diabetes mellitus (NIDDM), and other endocrinopathies. Tibial branches of the sciatic nerve reveal a progressive demyelination that progresses out of the Schwann cells (SCs) where electron-contrast deposits are accumulated while the minor lines or intermembranous SC contacts display exaggerated spacings. Cajal bands contain diversely contrasted vesicles adjacent to the abaxonal myelin layer with blemishes; they appear dispatched centripetally out of many narrow electron densities, regularly spaced around the myelin annulus. These anomalies widen and yield into sectors across the stacked myelin layers. Throughout the worse degradations, the adaxonal membrane remains along the axonal neuroplasm. This peripheral neuropathy with irresponsive leptin cannot modulate hypothalamic-pituitary-adrenal axis and SC neurosteroids, thus exacerbates NIDDM condition. Additionally, the ultrastructure of the progressive myelin alterations may have unraveled a peculiar, centripetal mode of trafficking maintenance of the peripheral nervous system myelin, while some adhesive glycoproteins remain between myelin layers, somewhat hindering the axon mutilation. Heading title: Peripheral neuropathy and myelin.
Collapse
Affiliation(s)
- Jacques Gilloteaux
- a Department of Anatomical Sciences , St George's University School of Medicine, K.B. Taylor Global Scholar's Program at Northumbria University , Newcastle upon Tyne , UK.,b Unité de Recherche en Physiologie Moléculaire (URPhyM), Laboratoire de Neurodégénérescence et Régénération, Département de Médecine , Université de Namur , Namur , Belgium
| | - Kritika Subramanian
- a Department of Anatomical Sciences , St George's University School of Medicine, K.B. Taylor Global Scholar's Program at Northumbria University , Newcastle upon Tyne , UK.,c Department of Clinical and Epidemiological Virology , Rega Institute of Medical Research, Katholiele Universiteit Leuven , Leuven , Belgium
| | - Nadia Solomon
- a Department of Anatomical Sciences , St George's University School of Medicine, K.B. Taylor Global Scholar's Program at Northumbria University , Newcastle upon Tyne , UK
| | - Charles Nicaise
- b Unité de Recherche en Physiologie Moléculaire (URPhyM), Laboratoire de Neurodégénérescence et Régénération, Département de Médecine , Université de Namur , Namur , Belgium
| |
Collapse
|
4
|
Kim JD, Park KE, Ishida J, Kako K, Hamada J, Kani S, Takeuchi M, Namiki K, Fukui H, Fukuhara S, Hibi M, Kobayashi M, Kanaho Y, Kasuya Y, Mochizuki N, Fukamizu A. PRMT8 as a phospholipase regulates Purkinje cell dendritic arborization and motor coordination. SCIENCE ADVANCES 2015; 1:e1500615. [PMID: 26665171 PMCID: PMC4672763 DOI: 10.1126/sciadv.1500615] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 10/21/2015] [Indexed: 06/02/2023]
Abstract
The development of vertebrate neurons requires a change in membrane phosphatidylcholine (PC) metabolism. Although PC hydrolysis is essential for enhanced axonal outgrowth mediated by phospholipase D (PLD), less is known about the determinants of PC metabolism on dendritic arborization. We show that protein arginine methyltransferase 8 (PRMT8) acts as a phospholipase that directly hydrolyzes PC, generating choline and phosphatidic acid. We found that PRMT8 knockout mice (prmt8 (-/-)) displayed abnormal motor behaviors, including hindlimb clasping and hyperactivity. Moreover, prmt8 (-/-) mice and TALEN-induced zebrafish prmt8 mutants and morphants showed abnormal phenotypes, including the development of dendritic trees in Purkinje cells and altered cerebellar structure. Choline and acetylcholine levels were significantly decreased, whereas PC levels were increased, in the cerebellum of prmt8 (-/-) mice. Our findings suggest that PRMT8 acts both as an arginine methyltransferase and as a PC-hydrolyzing PLD that is essential for proper neurological functions.
Collapse
Affiliation(s)
- Jun-Dal Kim
- Life Science Center, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8577, Japan
| | - Kyung-Eui Park
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8572, Japan
| | - Junji Ishida
- Life Science Center, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8577, Japan
| | - Koichiro Kako
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8572, Japan
| | - Juri Hamada
- Life Science Center, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8577, Japan
| | - Shuichi Kani
- Laboratory for Vertebrate Axis Formation, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan
| | - Miki Takeuchi
- Laboratory of Organogenesis and Organ Function, Bioscience and Biotechnology Center, Nagoya University, Nagoya, Aichi 464-8601, Japan
- Department of Molecular and Developmental Biology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8575, Japan
| | - Kana Namiki
- Department of Biochemistry and Molecular Pharmacology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chiba 260-8670, Japan
| | - Hajime Fukui
- Department of Cell Biology, National Cerebral and Cardiovascular Center Research Institute, Fujishirodai 5-7-1, Suita, Osaka 565-8565, Japan
| | - Shigetomo Fukuhara
- Department of Cell Biology, National Cerebral and Cardiovascular Center Research Institute, Fujishirodai 5-7-1, Suita, Osaka 565-8565, Japan
| | - Masahiko Hibi
- Laboratory for Vertebrate Axis Formation, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan
- Laboratory of Organogenesis and Organ Function, Bioscience and Biotechnology Center, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Makoto Kobayashi
- Department of Molecular and Developmental Biology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8575, Japan
| | - Yasunori Kanaho
- Department of Physiological Chemistry, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8575, Japan
| | - Yoshitoshi Kasuya
- Department of Biochemistry and Molecular Pharmacology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chiba 260-8670, Japan
| | - Naoki Mochizuki
- Department of Cell Biology, National Cerebral and Cardiovascular Center Research Institute, Fujishirodai 5-7-1, Suita, Osaka 565-8565, Japan
- AMED-CREST, National Cerebral and Cardiovascular Center Research Institute, Fujishirodai 5-7-1, Suita, Osaka 565-8565, Japan
| | - Akiyoshi Fukamizu
- Life Science Center, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8577, Japan
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8572, Japan
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8575, Japan
| |
Collapse
|
5
|
Affiliation(s)
- Jeffrey L Goldberg
- Department of Neurobiology, Stanford University School of Medicine, California 94305, USA.
| |
Collapse
|
6
|
Abstract
We initially isolated CTL1 from the electric lobe of brain through functional complementation of a yeast mutant deficient in choline transport. Here, we present the first characterization of an antibody to the C-terminal of CTL1. When full length torpedo CTL1 was expressed in oocytes, a broad 60 kDa band appeared concomitant with the detection of immunoreactivity at the plasma membrane. In, the native protein was prominent throughout the CNS and along the electric nerves. CTL1 immunolabeling was particularly conspicuous in the myelin sheath surrounding the electric nerve and in central myelinated structures. The association of the presumptive choline transporter, CTL1, with myelin membranes suggests a role for this new protein in lipid production.
Collapse
Affiliation(s)
- François-Marie Meunier
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, CNRS, 91198 Gif-sur-Yvette, France
| | | |
Collapse
|
7
|
Padilla S, Freeman EB, Tandon P, Wilson VZ. Locally synthesized phosphatidylcholine, but not protein, undergoes rapid retrograde axonal transport in the rat sciatic nerve. J Neurochem 1993; 60:1900-5. [PMID: 8473904 DOI: 10.1111/j.1471-4159.1993.tb13418.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Retrograde axonal transport of phosphatidylcholine in the sciatic nerve has been demonstrated only after injection of lipid precursors into the cell body region. We now report, however, that after microinjection (1 microliter) of [methyl-3H]choline chloride into the rat sciatic nerve (35-40 mm distal to the L4 and L5 dorsal root ganglia), time-dependent accumulation of 3H-labeled material occurred in dorsal root ganglia ipsilateral, but not contralateral, to the injection site. The level of radioactivity in the ipsilateral dorsal root ganglia was minimal at 2 h after isotope injection but was significantly increased at 7, 24, 48, and 72 h after intraneural isotope injection (n = 3-8 per time point); at these time points, all of the radiolabel in the chloroform/methanol extract of the ipsilateral dorsal root ganglia was present in phosphatidylcholine. The radioactivity in the water-soluble fraction did not show a time-dependent accumulation in the ipsilateral dorsal root ganglia as compared with the contralateral DRGs, ruling out transport or diffusion of precursor molecules. In addition, colchicine injection into the sciatic nerve proximal to the isotope injection site prevented the accumulation of radiolabel in the ipsilateral dorsal root ganglia. Therefore, this time-dependent accumulation of radiolabeled phosphatidylcholine in the ipsilateral dorsal root ganglia is most likely due to retrograde axonal transport of locally synthesized phospholipid material. Moreover, 24 h after injection of both [3H]choline and [35S]-methionine into the sciatic nerve, the ipsilateral/contralateral ratio of radiolabel was 11.7 for 3H but only 1.1 for 35S, indicating that only locally synthesized choline phospholipids, but not protein, were retrogradely transported.
Collapse
Affiliation(s)
- S Padilla
- Cellular and Molecular Toxicology Branch, U.S. Environmental Protection Agency, Chapel Hill, North Carolina 27711
| | | | | | | |
Collapse
|
8
|
Boiron F, Spivack WD, Deshmukh DS, Gould RM. Basis for phospholipid incorporation into peripheral nerve myelin. J Neurochem 1993; 60:320-9. [PMID: 8417153 DOI: 10.1111/j.1471-4159.1993.tb05854.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
To characterize the mechanism(s) for targeting of phospholipids to peripheral nerve myelin, we examined the kinetics of incorporation of tritiated choline-, glycerol-, and ethanolamine-labeled phospholipids into four subfractions: microsomes, mitochondria, myelin-like material, and purified myelin at 1, 6, and 24 h after precursors were injected into sciatic nerves of 23-24-day-old rats. As validation of the fractionation scheme, a lag (> 1 h) in the accumulation of labeled phospholipids in the myelin-containing subfractions was found. This lag signifies the time between synthesis on organelles in Schwann cell cytoplasm and transport to myelin. In the present study, we find that sphingomyelin (choline-labeled) accumulated in myelin-rich subfractions only at 6 and 24 h, whereas phosphatidylserine (glycerol-labeled) and plasmalogen (ethanolamine-labeled) accumulated in the myelin-rich fractions by 1 h. The later phospholipids accumulate preferentially in the myelin-like fraction. These results are consistent with the notion that the targeting of sphingomyelin, a lipid present in the outer myelin leaflet, is different from the targeting of phosphatidylserine and ethanolamine plasmalogen, lipids in the inner leaflet. These findings are discussed in light of the possibility that sphingomyelin targeting is Golgi apparatus based, whereas phosphatidylserine and ethanolamine plasmalogen use a more direct transport system. Furthermore, the routes of phospholipid targeting mimic routes taken by myelin proteins P0 (Golgi) and myelin basic proteins (more direct).
Collapse
Affiliation(s)
- F Boiron
- New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314
| | | | | | | |
Collapse
|
9
|
Padilla S, Pope CN. Retrograde axonal transport of locally synthesized phosphoinositides in the rat sciatic nerve. J Neurochem 1991; 57:415-22. [PMID: 1712828 DOI: 10.1111/j.1471-4159.1991.tb03768.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Although autoradiography has demonstrated local incorporation of [3H]inositol into axonal phospholipids after intraneural injection, retrograde axonal transport of phosphatidylinositol has only been demonstrated after injection of lipid precursor into the cell body regions (L4 and L5 dorsal root ganglia) of the sciatic nerve. We now report the retrograde axonal transport of inositol phospholipids synthesized locally in the axons. Following microinjection of myo-[3H]inositol into the rat sciatic nerve (50-55 mm distal to L4 and L5 dorsal root ganglia), a time-dependent accumulation of 3H label occurred in the dorsal root ganglia ipsilateral to the injection site. The ratio of dpm present in the ipsilateral dorsal root ganglia to that in the contralateral dorsal root ganglia was not significantly different from unity between 2 and 8 h following isotope injection but increased to 10-12-fold between 24 and 72 h following precursor injection. By 24 h following precursor injection, the ipsilateral/contralateral ratio of the water-soluble label in the dorsal root ganglia still remained approximately 1.0, whereas the corresponding ratio in the chloroform/methanol-soluble fraction was approximately 20. The time course of appearance of labeled lipids in the ipsilateral dorsal root ganglia after injection of precursor into the nerve at various distances from the dorsal root ganglia indicated a transport rate of at least 5 mm/h. Accumulation of label in the dorsal root ganglia could be prevented by intraneural injection of colchicine or ligation of the sciatic nerve between the dorsal root ganglia and the isotope injection site. These results demonstrate that inositol phospholipids synthesized locally in the sciatic nerve are retrogradely transported back to the nerve cell bodies located in the dorsal root ganglia.
Collapse
Affiliation(s)
- S Padilla
- Cellular and Molecular Toxicology Branch, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | | |
Collapse
|
10
|
Injections into Mouse Sciatic Nerve for in Vivo Studies of Quantitative, Short-Term Metabolism. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/b978-0-12-185257-3.50029-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
11
|
Affiliation(s)
- R M Gould
- Department of Pharmacology, New York State Institute for Basic Research in Developmental Disabilities, Staten Island 10314
| |
Collapse
|
12
|
Gould RM, Mattingly G. Regional localization of RNA and protein metabolism in Schwann cells in vivo. JOURNAL OF NEUROCYTOLOGY 1990; 19:285-301. [PMID: 1697335 DOI: 10.1007/bf01188399] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Schwann cells, which form and maintain extensive myelin sheaths, have the bulk of their lipid and protein synthesis restricted to the compact 'perinuclear' zone at the centre of the internode. Using teased fibre and quantitative electron microscopical autoradiography, we demonstrated that additional protein synthesis takes place in the lengthy processes of Schwann cell cytoplasm. This 'so-called' superficial cytoplasmic channel network forms a branching and anastomozing array that stretches between the perinuclear region and the distant paranodes. Protein synthesis apparently does not extend from this surface network into the Schmidt-Lanterman incisures or paranodal loops that circumscribe compact myelin. To maintain protein synthesis in these lengthy processes, Schwann cells transport a portion of their RNA along the superficial cytoplasmic channels at a rate (0.1 mm per day) that appears to be slightly lower than the transport rate reported for RNA along dendrites of hippocampal neurons in culture (0.5 mm per day). Nearly a week is required for labelled RNA to be transported from the Schwann cell nucleus to the paranodal terminals of the longer channels. The existence of this extended protein synthesis is not limited to myelinating Schwann cells. Schwann cell processes associated with small calibre axons also appear to synthesize some of their own proteins as the RNA needed to catalyze local translational events is transported into these processes.
Collapse
Affiliation(s)
- R M Gould
- Laboratory of Membrane Biology, New York State Institute for Basic Research in Developmental Disabilities, Staten Island 10314
| | | |
Collapse
|
13
|
Gould RM, Holshek J, Silverman W, Spivack WD. Localization of phospholipid synthesis to Schwann cells and axons. J Neurochem 1987; 48:1121-31. [PMID: 3819724 DOI: 10.1111/j.1471-4159.1987.tb05636.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Quantitative electron microscopic autoradiography was used to detect and characterize endoneurial sites of lipid synthesis in mouse sciatic nerve. Six tritiated phospholipid precursors (choline, serine, methionine, inositol, glycerol, and ethanolamine) and a protein precursor (proline) were individually injected into exposed nerves and after 2 h the mice were perfused with buffered aldehyde. The labeled segments of nerve were prepared for autoradiography with procedures that selectively remove nonincorporated precursors and other aqueous metabolites, while preserving nerve lipids (and proteins). At both the light and electron microscope levels, the major site of phospholipid and protein synthesis was the crescent-shaped perinuclear cytoplasm of myelinating Schwann cells. Other internodal Schwann cell cytoplasm, including that in surface channels, Schmidt-Lanterman incisures, and paranodal regions, was less well labeled than the perinuclear region. Newly formed proteins were selectively located in the Schwann cell nucleus. Lipid and protein formation was also detected in unmyelinated fiber bundles and in endoneurial and perineurial cells. Tritiated inositol was selectively incorporated into phospholipids in both myelinated axons and unmyelinated fibers. Like inositol, glycerol incorporation appeared particularly active in unmyelinated fibers. Quantitative autoradiographic analyses substantiated the following points: myelinating Schwann cells dominate phospholipid and protein synthesis, myelinated axons selectively incorporate tritiated inositol, phospholipid precursors label myelin sheaths and myelinated axons better than proline.
Collapse
|