HtrA2/Omi‐immunoreactive intraneuronal inclusions in the anterior horn of patients with sporadic and Cu/Zn superoxide dismutase (SOD1) mutant amyotrophic lateral sclerosis

Y. Kawamoto, H. Ito, Y. Kobayashi, Y. Suzuki, I. Akiguchi, H. Fujimura, S. Sakoda, H. Kusaka, A. Hirano and R. Takahashi (2010) Neuropathology and Applied Neurobiology 36, 331–344
HtrA2/Omi‐immunoreactive intraneuronal inclusions in the anterior horn of patients with sporadic and Cu/Zn superoxide dismutase (SOD1) mutant amyotrophic lateral sclerosis Aims: HtrA2/Omi is a mitochondrial serine protease that promotes the apoptotic processes, but the relationship between HtrA2/Omi and amyotrophic lateral sclerosis (ALS) is still unknown. The purpose of the present study was to determine whether abnormal expression of HtrA2/Omi occurs in patients with ALS. Methods: We prepared autopsied spinal cord tissues from 7 control subjects, 11 patients with sporadic ALS (SALS) and 4 patients with Cu/Zn superoxide dismutase (SOD1)‐related familial ALS (FALS). We then performed immunohistochemical studies on HtrA2/Omi using formalin‐fixed, paraffin‐embedded sections from all of the cases. Results: In the control subjects, the anterior horn cells were mildly to moderately immunostained with HtrA2/Omi. In the patients with SALS, strong HtrA2/Omi immunoreactivity was found in some skein‐like inclusions and round hyaline inclusions as well as many spheroids, but Bunina bodies were immunonegative for HtrA2/Omi. In the patients with SOD1‐related FALS, Lewy body‐like hyaline inclusions were observed in three cases and conglomerate inclusions were observed in the remaining case, and both types of inclusions were intensely immunopositive for HtrA2/Omi. Conclusions: These results suggest that abnormal accumulations of HtrA2/Omi may occur in several types of motor neuronal inclusions in the anterior horn from SALS and SOD1‐linked FALS cases, and that HtrA2/Omi may be associated with the pathogenesis of both types of ALS.