In the article “Calpain Is a Major Cell Death Effector in Selective Striatal Degeneration Induced In Vivo by 3-Nitropropionate: Implications for Huntington's Disease,” by Nicolas Bizat, Jean-Michel Hermel, Frédéric Boyer, Carine Jacquard, Christophe Créminon, Stéphane Ouary, Carole Escartin, Philippe Hantraye, Stan Krajewski, and Emmanuel Brouillet, which appeared on pages 5020–5030 of the June 15, 2003 issue, errors were uncovered in calculation spreadsheets used for determining absolute values of the proteolytic activities of caspase-3, caspase-8, caspase-9, and calpain using fluorimetric assays. Correcting the errors does not change the significance or interpretation of the study. However, the magnitude of changes induced by 3-NP is less than that initially reported. Corrected absolute values found in the striatum of control rats and at time points at which 3-NP treatment produced significant changes in the striatum are shown in the table below.
Table.
Corrected protease activity (in pmol · min-1 · mg-1; mean ± SD) in the striatum of control and 3-NP-treated rats
|
|
Acute 3-NP model |
Chronic 3-NP model |
||||
|---|---|---|---|---|---|---|
| Protease
|
Control
|
3-NP
|
Control
|
3-NP
|
||
| Caspase-9 | 9.51 ± 0.80 | No increase at 6, 12, 24, and 48 hra | 11.19 ± 1.53 | 19.54 ± 0.57 day 3; p < 0.0001 | ||
| Caspase-8 | 9.96 ± 1.25 | 13.07 ± 0.62 12 hr; p < 0.02 | 11.56 ± 0.63 | No increase from day 1 to day 5 | ||
| Caspase-3 | 11.42 ± 0.48 | 24.93 ± 1.37 24 hr; p < 0.0001 | 10.31 ± 1.57 | No increase from day 1 to day 5 | ||
| Calpain
|
22.87 ± 4.04
|
No increase at 6, 12, 24, and 48 hr
|
18.47 ± 2.22
|
41.14 ± 4.82 day 5; p < 0.0003
|
||
Activities were determined as described in Materials and Methods. Comparisons between groups were done by ANOVA and post hoc Scheffe F test. In these studies, absolute values of protease activity found in control cerebral cortex are close to those found in the control striatum. No increase induced by 3-NP was detected in the cerebral cortex.
Note that after correction of calculation errors, caspase-9 activity is not found to be increased in the striatum in the acute 3-NP model at 12 hr. This is consistent with Western blotting and immunohistochemistry indicating that processing of caspase-9 in this model occurs early after acute injection of 3-NP (see original Fig. 4).