1
|
BDNF Spinal Overexpression after Spinal Cord Injury Partially Protects Soleus Neuromuscular Junction from Disintegration, Increasing VAChT and AChE Transcripts in Soleus but Not Tibialis Anterior Motoneurons. Biomedicines 2022; 10:biomedicines10112851. [DOI: 10.3390/biomedicines10112851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/20/2022] [Accepted: 11/04/2022] [Indexed: 11/09/2022] Open
Abstract
After spinal cord transection (SCT) the interaction between motoneurons (MNs) and muscle is impaired, due to reorganization of the spinal network after a loss of supraspinal inputs. Rats subjected to SCT, treated with intraspinal injection of a AAV-BDNF (brain-derived neurotrophic factor) construct, partially regained the ability to walk. The central effects of this treatment have been identified, but its impact at the neuromuscular junction (NMJ) has not been characterized. Here, we compared the ability of NMJ pre- and postsynaptic machinery in the ankle extensor (Sol) and flexor (TA) muscles to respond to intraspinal AAV-BDNF after SCT. The gene expression of cholinergic molecules (VAChT, ChAT, AChE, nAChR, mAChR) was investigated in tracer-identified, microdissected MN perikarya, and in muscle fibers with the use of qPCR. In the NMJs, a distribution of VAChT, nAChR and Schwann cells was studied by immunofluorescence, and of synaptic vesicles and membrane active zones by electron microscopy. We showed partial protection of the Sol NMJs from disintegration, and upregulation of the VAChT and AChE transcripts in the Sol, but not the TA MNs after spinal enrichment with BDNF. We propose that the observed discrepancy in response to BDNF treatment is an effect of difference in the TrkB expression setting BDNF responsiveness, and of BDNF demands in Sol and TA muscles.
Collapse
|
2
|
Ji B, Wojtaś B, Skup M. Molecular Identification of Pro-Excitogenic Receptor and Channel Phenotypes of the Deafferented Lumbar Motoneurons in the Early Phase after SCT in Rats. Int J Mol Sci 2022; 23:ijms231911133. [PMID: 36232433 PMCID: PMC9569670 DOI: 10.3390/ijms231911133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/19/2022] [Accepted: 09/19/2022] [Indexed: 02/07/2023] Open
Abstract
Spasticity impacts the quality of life of patients suffering spinal cord injury and impedes the recovery of locomotion. At the cellular level, spasticity is considered to be primarily caused by the hyperexcitability of spinal α-motoneurons (MNs) within the spinal stretch reflex circuit. Here, we hypothesized that after a complete spinal cord transection in rats, fast adaptive molecular responses of lumbar MNs develop in return for the loss of inputs. We assumed that early loss of glutamatergic afferents changes the expression of glutamatergic AMPA and NMDA receptor subunits, which may be the forerunners of the developing spasticity of hindlimb muscles. To better understand its molecular underpinnings, concomitant expression of GABA and Glycinergic receptors and serotoninergic and noradrenergic receptors, which regulate the persistent inward currents crucial for sustained discharges in MNs, were examined together with voltage-gated ion channels and cation-chloride cotransporters. Using quantitative real-time PCR, we showed in the tracer-identified MNs innervating extensor and flexor muscles of the ankle joint multiple increases in transcripts coding for AMPAR and 5-HTR subunits, along with a profound decrease in GABAAR, GlyR subunits, and KCC2. Our study demonstrated that both MNs groups similarly adapt to a more excitable state, which may increase the occurrence of extensor and flexor muscle spasms.
Collapse
Affiliation(s)
- Benjun Ji
- Group of Restorative Neurobiology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Bartosz Wojtaś
- Laboratory of Sequencing, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Małgorzata Skup
- Group of Restorative Neurobiology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
- Correspondence:
| |
Collapse
|
3
|
Grycz K, Głowacka A, Ji B, Krzywdzińska K, Charzyńska A, Czarkowska-Bauch J, Gajewska-Woźniak O, Skup M. Regulation of perineuronal net components in the synaptic bouton vicinity on lumbar α-motoneurons in the rat after spinalization and locomotor training: New insights from spatio-temporal changes in gene, protein expression and WFA labeling. Exp Neurol 2022; 354:114098. [DOI: 10.1016/j.expneurol.2022.114098] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 03/31/2022] [Accepted: 04/24/2022] [Indexed: 11/25/2022]
|
4
|
McIntyre WB, Pieczonka K, Khazaei M, Fehlings MG. Regenerative replacement of neural cells for treatment of spinal cord injury. Expert Opin Biol Ther 2021; 21:1411-1427. [PMID: 33830863 DOI: 10.1080/14712598.2021.1914582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Introduction: Traumatic Spinal Cord Injury (SCI) results from primary physical injury to the spinal cord, which initiates a secondary cascade of neural cell death. Current therapeutic approaches can attenuate the consequences of the primary and secondary events, but do not address the degenerative aspects of SCI. Transplantation of neural stem/progenitor cells (NPCs) for the replacement of the lost/damaged neural cells is suggested here as a regenerative approach that is complementary to current therapeutics.Areas Covered: This review addresses how neurons, oligodendrocytes, and astrocytes are impacted by traumatic SCI, and how current research in regenerative-NPC therapeutics aims to restore their functionality. Methods used to enhance graft survival, as well as bias progenitor cells towards neuronal, oligodendrogenic, and astroglia lineages are discussed.Expert Opinion: Despite an NPC's ability to differentiate into neurons, oligodendrocytes, and astrocytes in the transplant environment, their potential therapeutic efficacy requires further optimization prior to translation into the clinic. Considering the temporospatial identity of NPCs could promote neural repair in region specific injuries throughout the spinal cord. Moreover, understanding which cells are targeted by NPC-derived myelinating cells can help restore physiologically-relevant myelin patterns. Finally, the duality of astrocytes is discussed, outlining their context-dependent importance in the treatment of SCI.
Collapse
Affiliation(s)
- William Brett McIntyre
- Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Katarzyna Pieczonka
- Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Mohamad Khazaei
- Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Michael G Fehlings
- Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.,Department of Surgery, University of Toronto, Toronto, ON, Canada
| |
Collapse
|