Alteration of SLP2-like immunolabeling in mitochondria signifies early cellular damage in developing and adult mouse brain

Mitochondria play a critical role in various pathways of regulated cell death. Here we propose a novel method for detection of initial derangement of mitochondria in degenerating and dying neuronal cells. The method is based on our recent finding that antibodies directed against the cannabinoid type...

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Veröffentlicht in:The European journal of neuroscience 2016-01, Vol.43 (2), p.245-257
Hauptverfasser: Morozov, Yury M., Sun, Yu-Yo, Kuan, Chia-Yi, Rakic, Pasko
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Sprache:eng
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Zusammenfassung:Mitochondria play a critical role in various pathways of regulated cell death. Here we propose a novel method for detection of initial derangement of mitochondria in degenerating and dying neuronal cells. The method is based on our recent finding that antibodies directed against the cannabinoid type 1 receptor (CB1) also bind the mitochondrial stomatin‐like protein 2 (SLP2) that belongs to an inner mitochondrial membrane protein complex. It is well established that SLP2 regulates mitochondrial biogenesis and respiratory functions. We now show that anti‐CB1 antibodies recognize conformational epitopes but not the linear amino acid sequence of SLP2. In addition we found that anti‐CB1 serum mostly labels swollen mitochondria with early or advanced stages of pathology in mouse brain while other proteins of the complex may mask epitopes of SLP2 in the normal mitochondria. Although neurons and endothelial cells in healthy brains contain occasional immunopositive mitochondria detectable with anti‐CB1 serum, their numbers increase significantly after hypoxic insults in parallel with signs of cellular damage. Moreover, use of electron microscopy suggests relocation of SLP2 from its normal functional position in the inner mitochondrial membrane into the mitochondrial matrix in pathological cells. Thus, SLP2‐like immunolabeling serves as an in situ histochemical target detecting early derangement of mitochondria. Anti‐CB1 serum is crucial for this purpose because available anti‐SLP2 antibodies do not provide selective labeling of mitochondria in the fixed tissue. This new method of detecting mitochondrial dysfunction can benefit the in vitro research of human diseases and developmental disorders by enabling analysis in live animal models. SLP2‐like immunolabeling with CB1–L31 serum serves as an in situ histochemical marker detecting early derangement of mitochondria and containing those cells. CB1–L31 antibodies recognize conformational epitopes, but not linear amino acid sequence of SLP2. We hypothesize that relocation of SLP2 from its normal functional position in the inner mitochondrial membrane into the mitochondrial matrix correlates with mitochondrial dysfunction such as opening of the mitochondrial permeability transition pore that leads to further cellular pathology.
ISSN:0953-816X
1460-9568
DOI:10.1111/ejn.13124