Frank M. Longo, M.D., Ph.D.

Publication Details

  • Modulation of p75(NTR)-dependent motor neuron death by a small non-peptidyl mimetic of the neurotrophin loop 1 domain EUROPEAN JOURNAL OF NEUROSCIENCE Pehar, M., Cassina, P., Vargas, M. R., Xie, Y., Beckman, J. S., Massa, S. M., Longo, F. M., Barbeito, L. 2006; 24 (6): 1575-1580

    Abstract:

    The p75 neurotrophin receptor (p75NTR) is expressed by degenerating spinal motor neurons in amyotrophic lateral sclerosis (ALS). The mature and pro-form of nerve growth factor (NGF) activate p75NTR to trigger motor neuron apoptosis. However, attempts to modulate p75NTR-mediated neuronal death in ALS models by downregulating or antagonizing p75NTR with synthetic peptides have led to only modest results. Recently, a novel ligand of p75NTR, compound LM11A-24, has been identified. It is a non-peptidyl mimetic of the neurotrophin loop 1 domain that promotes hippocampal neuron survival through p75NTR and exerts protection against p75NTR-mediated apoptosis of oligodendrocytes induced by proNGF. Thus, LM11A-24 appears to activate p75NTR-linked survival but not death mechanisms, and may interfere with the ability of neurotrophins to induce apoptosis. Given these findings, we hypothesized that LM11A-24 might be a particularly potent inhibitor of motor neuron degeneration. We examined the effects of LM11A-24 on apoptosis of cultured rat embryonic motor neurons. Interestingly, in contrast to the effects observed in hippocampal cultures, LM11A-24 was unable to prevent motor neuron apoptosis induced by trophic factor deprivation. However, picomolar concentrations of LM11A-24 prevented p75NTR-dependent motor neuron death induced by either exogenous addition of NGF or spinal cord extracts from symptomatic superoxide dismutase-1G93A mice, in the presence of low steady-state concentrations of nitric oxide. LM11A-24 also inhibited motor neuron death induced by NGF-producing reactive astrocytes in co-culture conditions. These studies suggest that modulation of p75NTR by small molecule ligands targeting this receptor might constitute a novel strategy for preventing motor neuron degeneration.

    View details for DOI 10.1111/j.1460-9568.2006.05040.x

    View details for Web of Science ID 000240660800007

    View details for PubMedID 17004921

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