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Thompson D, Odufuwa AE, Brissette CA, Watt JA. Transcriptome and methylome of the supraoptic nucleus provides insights into the age-dependent loss of neuronal plasticity. Front Aging Neurosci 2023; 15:1223273. [PMID: 37711995 PMCID: PMC10498476 DOI: 10.3389/fnagi.2023.1223273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/08/2023] [Indexed: 09/16/2023] Open
Abstract
The age-dependent loss of neuronal plasticity is a well-known phenomenon that is poorly understood. The loss of this capacity for axonal regeneration is emphasized following traumatic brain injury, which is a major cause of disability and death among adults in the US. We have previously shown the intrinsic capacity of magnocellular neurons within the supraoptic nucleus to undergo axonal regeneration following unilateral axotomization in an age-dependent manner. The aim of this research was to determine the age-dependent molecular mechanisms that may underlie this phenomenon. As such, we characterized the transcriptome and DNA methylome of the supraoptic nucleus in uninjured 35-day old rats and 125-day old rats. Our data indicates the downregulation of a large number of axonogenesis related transcripts in 125-day old rats compared to 35-day old rats. Specifically, several semaphorin and ephrin genes were downregulated, as well as growth factors including FGF's, insulin-like growth factors (IGFs), and brain-derived neurotrophic factor (BDNF). Differential methylation analysis indicates enrichment of biological processes involved in axonogenesis and axon guidance. Conversely, we observed a robust and specific upregulation of MHCI related transcripts. This may involve the activator protein 1 (AP-1) transcription factor complex as motif analysis of differentially methylated regions indicate enrichment of AP-1 binding sites in hypomethylated regions. Together, our data suggests a loss of pro-regenerative capabilities with age which would prevent axonal growth and appropriate innervation following injury.
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Affiliation(s)
| | | | | | - John A. Watt
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States
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Askvig JM, Irmen RE, Dalzell TS, Whiteman ST, Andersen MJ, Said Z, Nguyen DQ, Bexell SH, Maruska BL. Axotomy results in an increase in Thy-1 protein in the 35-day-old rat supraoptic nucleus. Exp Brain Res 2023; 241:851-864. [PMID: 36757564 DOI: 10.1007/s00221-023-06562-4] [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: 10/06/2022] [Accepted: 01/19/2023] [Indexed: 02/10/2023]
Abstract
We demonstrated previously that the hypothalamic supraoptic nucleus (SON) undergoes an axonal sprouting response following a unilateral lesion of the hypothalamo-neurohypophysial tract in a 35-day-old rat to repopulate the partially denervated neural lobe (NL). However, no sprouting occurs following the same injury in a 125-day-old rat. We previously reported a significant increase in Thy-1 protein in the SON of a 125-day-old rat compared to a 35-day-old rat in the absence of injury. Thy-1 is a cell surface glycoprotein shown to inhibit axonal outgrowth following injury; however, we did not look at axotomy's effect on Thy-1 in the SON. Therefore, we sought to determine the integrin ligands that bind Thy-1 in the SON and how axotomy impacts Thy-1. Like what others have shown, the co-immunoprecipitation analysis demonstrated that Thy-1 interacts with αvß3 and αvß5 integrin dimers in the SON. We used western blot analysis to examine protein levels of Thy-1 and integrin subunits following injury in the 35- and 125-day-old rat SON and NL. Our results demonstrated that Thy-1 protein levels increase in the lesion SON in a 35-day-old rat. The quantitative dual-fluorescent analysis showed that the increase in Thy-1 in the lesion SON occurred in astrocytes. There was no change in Thy-1 or integrin protein levels following injury in the 125-day-old following injury. Furthermore, the axotomy significantly decreased Thy-1 protein levels in the NL of both 35- and 125-day-old rats. These results provide evidence that Thy-1 protein levels are injury dependent in the magnocellular neurosecretory system.
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Affiliation(s)
- Jason M Askvig
- Department of Biology and Neuroscience Program, Concordia College, Jason Askvig, 901 S 8th St, Moorhead, MN, 56562, USA.
| | - Riley E Irmen
- Department of Biology and Neuroscience Program, Concordia College, Jason Askvig, 901 S 8th St, Moorhead, MN, 56562, USA
| | - Talia S Dalzell
- Department of Biology and Neuroscience Program, Concordia College, Jason Askvig, 901 S 8th St, Moorhead, MN, 56562, USA
| | - Sara T Whiteman
- Department of Biology and Neuroscience Program, Concordia College, Jason Askvig, 901 S 8th St, Moorhead, MN, 56562, USA
| | - Marissa J Andersen
- Department of Biology and Neuroscience Program, Concordia College, Jason Askvig, 901 S 8th St, Moorhead, MN, 56562, USA
| | - Zaynab Said
- Department of Biology and Neuroscience Program, Concordia College, Jason Askvig, 901 S 8th St, Moorhead, MN, 56562, USA
| | - Duong Q Nguyen
- Department of Biology and Neuroscience Program, Concordia College, Jason Askvig, 901 S 8th St, Moorhead, MN, 56562, USA
| | - Sydney H Bexell
- Department of Biology and Neuroscience Program, Concordia College, Jason Askvig, 901 S 8th St, Moorhead, MN, 56562, USA
| | - Brooke L Maruska
- Department of Biology and Neuroscience Program, Concordia College, Jason Askvig, 901 S 8th St, Moorhead, MN, 56562, USA
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Paul MH, Hildebrandt-Einfeldt L, Beeg Moreno VJ, Del Turco D, Deller T. Maturation-Dependent Differences in the Re-innervation of the Denervated Dentate Gyrus by Sprouting Associational and Commissural Mossy Cell Axons in Organotypic Tissue Cultures of Entorhinal Cortex and Hippocampus. Front Neuroanat 2021; 15:682383. [PMID: 34122019 PMCID: PMC8194403 DOI: 10.3389/fnana.2021.682383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 04/28/2021] [Indexed: 11/30/2022] Open
Abstract
Sprouting of surviving axons is one of the major reorganization mechanisms of the injured brain contributing to a partial restoration of function. Of note, sprouting is maturation as well as age-dependent and strong in juvenile brains, moderate in adult and weak in aged brains. We have established a model system of complex organotypic tissue cultures to study sprouting in the dentate gyrus following entorhinal denervation. Entorhinal denervation performed after 2 weeks postnatally resulted in a robust, rapid, and very extensive sprouting response of commissural/associational fibers, which could be visualized using calretinin as an axonal marker. In the present study, we analyzed the effect of maturation on this form of sprouting and compared cultures denervated at 2 weeks postnatally with cultures denervated at 4 weeks postnatally. Calretinin immunofluorescence labeling as well as time-lapse imaging of virally-labeled (AAV2-hSyn1-GFP) commissural axons was employed to study the sprouting response in aged cultures. Compared to the young cultures commissural/associational sprouting was attenuated and showed a pattern similar to the one following entorhinal denervation in adult animals in vivo. We conclude that a maturation-dependent attenuation of sprouting occurs also in vitro, which now offers the chance to study, understand and influence maturation-dependent differences in brain repair in these culture preparations.
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Affiliation(s)
- Mandy H Paul
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe-University Frankfurt, Frankfurt, Germany
| | - Lars Hildebrandt-Einfeldt
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe-University Frankfurt, Frankfurt, Germany
| | - Viktor J Beeg Moreno
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe-University Frankfurt, Frankfurt, Germany
| | - Domenico Del Turco
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe-University Frankfurt, Frankfurt, Germany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe-University Frankfurt, Frankfurt, Germany
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Whiteman ST, Askvig JM. Astrocytic role of Thy-1 induced inhibition of axonal sprouting. Neural Regen Res 2021; 16:1192-1193. [PMID: 33269771 PMCID: PMC8224143 DOI: 10.4103/1673-5374.300429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
| | - Jason M Askvig
- Department of Biology, Concordia College, Moorhead, MN, USA
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Askvig JM, Dalzell TS, Toumeh N, Kuball PT, Whiteman ST, Bye EW, Andersen MJ, McCarthy MG, Irmen RE, Bexell SH, Benolken MM, Maruska BL, Nordmann SE. Age-dependent increase in Thy-1 protein in the rat supraoptic nucleus. Heliyon 2020; 6:e03501. [PMID: 32181386 PMCID: PMC7066247 DOI: 10.1016/j.heliyon.2020.e03501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/15/2019] [Accepted: 02/24/2020] [Indexed: 11/29/2022] Open
Abstract
Mature mammalian CNS neurons often do not recover successfully following injury. To this point, unilateral lesion of the hypothalamo-neurohypophysial tract results in collateral sprouting from uninjured axons of the supraoptic nucleus (SON) in 35-day-old but not in 125-day-old rats. Thus, it appears that there are age-related changes within the SON that preclude the older rat from recovering following axotomy. We hypothesize that the intrinsic capacity for axon reorganization may depend, in part, on age-related alterations in cell adhesion molecules that allow normal astrocyte-neuron interactions in the SON. In support of our hypothesis, numerous reports have shown that Thy-1 is increased in neurons at the cessation of axon outgrowth. Therefore, we compared protein levels of Thy-1 and the Thy-1 interacting integrin subunits, alpha-v (αv), beta-3 (ß3), and beta-5 (ß5), in 35- and 125-day-old SON using western blot analysis. Our results demonstrated that there was significantly more Thy-1 protein in the 125-day-old SON compared to 35-day-old SON, but no change in the protein levels of the integrin subunits. Furthermore, we localized Thy-1-, αv integrin-, ß3 integrin-, and ß5 integrin-immunoreactivity to both neurons and astrocytes in the SON. Altogether, our results suggest that the observed increase in Thy-1 protein levels in the SON with age may contribute to an environment that prevents collateral axonal sprouting in the SON of the 125-day-old rat.
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Affiliation(s)
- Jason M Askvig
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Talia S Dalzell
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Nadia Toumeh
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Phillip T Kuball
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Sara T Whiteman
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Erik W Bye
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | | | | | - Riley E Irmen
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Sydney H Bexell
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Molly M Benolken
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
| | - Brooke L Maruska
- Department of Biology, Concordia College, Moorhead, MN, 56562, USA
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