cytochrome-c-t and Multiple-System-Atrophy

The mitochondria play an important role in apoptotic cell death, and the released cytochrome c from the mitochondria promotes the formation of the apoptosome, which contains cytochrome c, Apaf-1 and caspase-9, resulting in the activation of caspase-9 and the promotion of the apoptotic cascade. To investigate the role of mitochondria-dependent apoptotic cell death in patients with multiple system atrophy (MSA), we performed immunohistochemical studies on apoptosome-related proteins in formalin-fixed, paraffin-embedded sections from 8 normal subjects and 10 patients with MSA. We then performed double-labeling immunohistochemistry for activated caspase-9 and α-synuclein in some sections from 10 patients with MSA. In the brains with MSA, glial cytoplasmic inclusions (GCIs) and neuronal cytoplasmic inclusions (NCIs) were intensely immunoreactive for cytochrome c, Apaf-1 and caspase-9. Activated caspase-9 immunoreactivities were also confirmed to be densely localized to both GCIs and NCIs using two types of anti-cleaved caspase-9 antibodies. The semiquantitative analyses using the upper pontine sections double-immunostained with cleaved caspase-9 and α-synuclein demonstrated that approximately 80% of GCIs and NCIs were immunopositive for cleaved caspase-9. Our results suggest that the formation of the apoptosome accompanied by the activation of caspase-9 may occur in brains affected by MSA, and that a mitochondria-dependent apoptotic pathway may be partially associated with the pathogenesis of MSA.

Topics: Aged; Apoptosis; Apoptotic Protease-Activating Factor 1; Brain; Caspase 9; Cytochromes c; Female; Humans; Inclusion Bodies; Male; Middle Aged; Multiple System Atrophy; Neuroglia; Neurons

Multiple system atrophy (MSA) is an adult-onset sporadic neurodegenerative disorder of unknown etiology featuring parkinsonism, ataxia, and autonomic failure in any combination. Because disease progression in MSA is rapid and no drug treatment consistently benefits MSA patients in the long term, neuroprotective or regenerative strategies may be invaluable in the management of MSA patients. In this study, we investigated whether human mesenchymal stem cells (hMSCs) had a protective effect on MSA using an animal model of double-toxin-induced MSA parkinsonism (MSA-P). MSA-P was established with coinjections of MPTP and 3-NP; hMSCs were injected into the tail vein 1 day after the last toxin injection. Three groups of mice were compared (i.e., control, MPTP + 3-NP, and MPTP + 3-NP with hMSC treatment) through histopathological, behavioral, and Western blot analyses. In the substantia nigra (SN) and the striatum, 2.0% and 3.8% of total injected hMSCs were observed, respectively. Compared with double-toxin-treated mice, hMSC treatment in double-toxin-treated mice significantly increased survival of TH- and NeuN-immunoreactive cells in the SN and the striatum, with coincident improvement in motor behavior. Additionally, hMSC treatment significantly decreased double-toxin-induced microglial and astroglial activation in the SN and striatum. Western blot analysis showed that hMSC administration in double-toxin-treated mice increased the expression of p-Akt and Bcl-2 and decreased Bax and cytochrome c expression. This study demonstrates that hMSC treatment protected against loss of neurons in the SN and the striatum induced by double toxin exposure, which may be mediated by modulation of inflammatory and cell survival and death signaling-pathway as the hMSCs migrated from the peripheral circulation into the SN and striatum.

Topics: Animals; bcl-2-Associated X Protein; Corpus Striatum; Cytochromes c; Disease Models, Animal; Humans; Male; Mesenchymal Stem Cell Transplantation; Mice; Mice, Inbred C57BL; Motor Activity; MPTP Poisoning; Multiple System Atrophy; Neurotoxins; Nitro Compounds; Parkinsonian Disorders; Propionates; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Substantia Nigra