Specific vulnerability of mouse spinal cord motoneurons to membrane depolarization

Gou-Fàbregas, Myriam; Garcerá, Ana; Mincheva, Stefka; Pérez-García, M. Jose; Comella, Joan X.; Soler, Rosa M.

doi:10.1111/j.1471-4159.2009.06278.x

Cited by 24 publications

(26 citation statements)

References 44 publications

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“…L-type Ca 2+ channels (Cav1.2) can also contribute to Ca 2+ entry into mouse motor terminals (Urbano et al, 2002) and into optic nerve axons during anoxia (Brown et al, 2001). Inhibition of P/Q-type and L-type channels reduced depolarization-induced death of cultured embryonic mouse motor neurons (Gou-Fabregas et al, 2009). Figs.…”

Section: Resultsmentioning

confidence: 99%

Calcium dependence of damage to mouse motor nerve terminals following oxygen/glucose deprivation

Talbot

David

Barrett

et al. 2012

Experimental Neurology

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Motor nerve terminals are especially sensitive to an ischemia/reperfusion stress. We applied an in vitro model of this stress, oxygen/glucose deprivation (OGD), to mouse neuromuscular preparations to investigate how Ca2+ contributes to stress-induced motor terminal damage. Measurements using an ionophoretically-injected fluorescent [Ca2+] indicator demonstrated an increase in intra-terminal [Ca2+] following OGD onset. When OGD was terminated within 20–30 min of the increase in resting [Ca2+], these changes were sometimes reversible; in other cases [Ca2+] remained high and the terminal degenerated. Endplate innervation was assessed morphometrically following 22 min OGD and 120 min reoxygenation (32.5 °C). Stress-induced motor terminal degeneration was Ca2+-dependent. Median post-stress endplate occupancy was only 26% when the bath contained the normal 1.8 mM Ca2+, but increased to 81% when Ca2+ was absent. Removal of Ca2+ only during OGD was more protective than removal of Ca2+ only during reoxygenation. Post-stress endplate occupancy was partially preserved by pharmacological inhibition of various routes of Ca2+ entry into motor terminals, including voltage-dependent Ca2+ channels (ω-agatoxin-IVA, nimodipine) and the plasma membrane Na+/Ca2+ exchanger (KB-R7943). Inhibition of a Ca2+-dependent protease with calpain inhibitor VI was also protective. These results suggest that most of the OGD-induced motor terminal damage is Ca2+-dependent, and that inhibition of Ca2+ entry or Ca2+-dependent proteolysis can reduce this damage. There was no significant difference between the response of wild-type and presymptomatic superoxide dismutase 1 G93A mutant terminals to OGD, or in their response to the protective effect of the tested drugs.

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Section: Resultsmentioning

confidence: 99%

Calcium dependence of damage to mouse motor nerve terminals following oxygen/glucose deprivation

Talbot

David

Barrett

et al. 2012

Experimental Neurology

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“…22, 45 Isolated cells were pooled in a tube containing culture medium and plated. All procedures were in accordance with the Spanish Council on Animal Care and approved by the University of Lleida Advisory Committee on Animal Services.…”

Section: Methodsmentioning

confidence: 99%

“…45, 46 Total cell lysates were resolved in SDS-polyacrylamide gels and transferred onto polyvinylidene difluoride Immobilon-P transfer membrane filters (Millipore, Billerica, MA, USA) using an Amersham Biosciences semidry Trans-Blot (Buckinghamshire, UK). The membranes were blotted with anti-SMN antibody (1 : 5000); anti-Bcl-x L antibody (1 : 2000; BD Transduction Laboratories, Franklin Lakes, NJ, USA); anti-LC3 antibody (1 : 1000); anti-Beclin1 antibody (1 : 1000; Cell Signaling Technology, Boston, MA, USA).…”

Section: Methodsmentioning

confidence: 99%

Survival motor neuron protein reduction deregulates autophagy in spinal cord motoneurons in vitro

et al. 2013

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Spinal muscular atrophy (SMA) is a genetic disorder characterized by degeneration of spinal cord motoneurons (MNs), resulting in muscular atrophy and weakness. SMA is caused by mutations in the Survival Motor Neuron 1 (SMN1) gene and decreased SMN protein. SMN is ubiquitously expressed and has a general role in the assembly of small nuclear ribonucleoproteins and pre-mRNA splicing requirements. SMN reduction causes neurite degeneration and cell death without classical apoptotic features, but the direct events leading to SMN degeneration in SMA are still unknown. Autophagy is a conserved lysosomal protein degradation pathway whose precise roles in neurodegenerative diseases remain largely unknown. In particular, it is unclear whether autophagosome accumulation is protective or destructive, but the accumulation of autophagosomes in the neuritic beadings observed in several neurite degeneration models suggests a close relationship between the autophagic process and neurite collapse. In the present work, we describe an increase in the levels of the autophagy markers including autophagosomes, Beclin1 and light chain (LC)3-II proteins in cultured mouse spinal cord MNs from two SMA cellular models, suggesting an upregulation of the autophagy process in Smn (murine survival motor neuron protein)-reduced MNs. Overexpression of Bcl-xL counteracts LC3-II increase, contributing to the hypothesis that the protective role of Bcl-xL observed in some SMA models may be mediated by its role in autophagy inhibition. Our in vitro experimental data indicate an upregulation in the autophagy process and autophagosome accumulation in the pathogenesis of SMA, thus providing a valuable clue in understanding the mechanisms of axonal degeneration and a possible therapeutic target in the treatment of SMA.

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“…MN cultures were prepared from embryonic day 12.5 (E12.5) CD1 male and female mouse spinal cords, essentially as described previously (Arce et al, 1999;Gou-Fabregas et al, 2009), with modifications. Briefly, mouse embryo spinal cords were dissected and the dorsal half removed.…”

Section: Methodsmentioning

confidence: 99%

“…NTFs promoting MN survival in vivo and in vitro belong to different gene families and activate several signaling pathways (Soler et al, 1999;Dolcet et al, 2001). To maintain MNs alive in culture, we (Gou-Fabregas et al, 2009) and others (Arce et al, 1999) use a cocktail of NTFs to achieve the maximal cell survival rates. We analyze the intracellular mechanisms involved in MN survival induced by the NTF cocktail.…”

Section: Introductionmentioning

confidence: 99%

The Canonical Nuclear Factor-κB Pathway Regulates Cell Survival in a Developmental Model of Spinal Cord Motoneurons

Mincheva¹,

Garcerá²,

Gou-Fàbregas³

et al. 2011

J. Neurosci.

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In vivo and in vitro motoneuron survival depends on the support of neurotrophic factors. These factors activate signaling pathways related to cell survival or inactivate proteins involved in neuronal death. In the present work, we analyzed the involvement of the nuclear factor-B (NF-B) pathway in mediating mouse spinal cord motoneuron survival promoted by neurotrophic factors. This pathway comprises ubiquitously expressed transcription factors that could be activated by two different routes: the canonical pathway, associated with IKK␣/IKK␤ kinase phosphorylation and nuclear translocation RelA (p65)/p50 transcription factors; and the noncanonical pathway, related to IKK␣ kinase homodimer phosphorylation and RelB/p52 transcription factor activation. In our system, we show that neurotrophic factors treatment induced IKK␣ and IKK␤ phosphorylation and RelA nuclear translocation, suggesting NF-B pathway activation. Protein levels of different members of the canonical or noncanonical pathways were reduced in a primary culture of isolated embryonic motoneurons using an interference RNA approach. Even in the presence of neurotrophic factors, selective reduction of IKK␣, IKK␤, or RelA proteins induced cell death. In contrast, RelB protein reduction did not have a negative effect on motoneuron survival. Together these results demonstrated that the canonical NF-B pathway mediates motoneuron survival induced by neurotrophic factors, and the noncanonical pathway is not related to this survival effect. Canonical NF-B blockade induced an increase of Bim protein level and apoptotic cell death. Bcl-x L overexpression or Bax reduction counteracted this apoptotic effect. Finally, RelA knockdown causes changes of CREB and Smn protein levels.

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Specific vulnerability of mouse spinal cord motoneurons to membrane depolarization

Cited by 24 publications

References 44 publications

Calcium dependence of damage to mouse motor nerve terminals following oxygen/glucose deprivation

Calcium dependence of damage to mouse motor nerve terminals following oxygen/glucose deprivation

Survival motor neuron protein reduction deregulates autophagy in spinal cord motoneurons in vitro

The Canonical Nuclear Factor-κB Pathway Regulates Cell Survival in a Developmental Model of Spinal Cord Motoneurons

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