In the article “GABAB Receptor Activation Protects Neurons from Apoptosis via IGF-1 Receptor Transactivation,” by Haijun Tu, Chanjuan Xu, Wenhua Zhang, Qiuyao Liu, Philippe Rondard, Jean-Philippe Pin, and Jianfeng Liu, which appeared on pages 749–759 of the January 13, 2010 issue, similarities were identified across several figures. The Western blot images of the control lane, depicting the expression level of total Akt, in Figures 3C, 4D, and 5B (right panel) appear to be misplaced. Upon investigation, errors with the legend for Figures 2C and 7 were also identified. The authors note that:
We found that the total Akt lanes (used as loading controls) in the left panel of Figure 4A and the right panel of Figure 4D look a bit similar. We also found a similar situation with the total Akt lanes (used as loading controls) between Figure 3A and 3C and between Figure 5A and 5B. We are not sure if they were duplicates that were misplaced as an error, but unfortunately due to the time lapsed, we were unable to locate the original western blot films of these figure panels. Out of an abundance of caution, we decided to validate the results by reperforming all the experiments described in Figures 4D, 3C, and 5B, which we suspect might contain total Akt lanes duplicated from others. The experiments were reperformed three times independently, and the statistical analyses and the data from these panels were reproduced and confirmed.
Meanwhile, we found that two labels in Figure 7F are incorrect, in which pAkt should be Akt and Akt should be pAkt.
We did not list N numbers in Figure 2C. The data shown in Figure 2C is one representative experiment from two biological replicates for the Foskolin treatment and three biological replicates for the Baclofen treatment. The error bars for some data points in the control curve seem to be “missing.” This appears to have resulted from the very small size of the error bars of these data points. If we zoom in to take a closer look, these tiny error bars then become visible, though still small. Since the differences between the control curve with Foskolin treatment and the curve with Baclofen treatment are so large and obvious, we did not perform statistical analysis between the two groups. The lack of a normal distribution pattern of the data points also defeats the purpose of statistical analysis.
We have now updated the legend of Figure 2C. Specifically, we have now added clarification to explain why the control curve has no error bar and no statistical analysis. As suggested by the editor, we have also included a statement that no conclusions are affected.
The corrected legend for Figure 2, corrected Figures 3–5, and corrected Figure 7 appear below. These issues do not affect the conclusions of the paper, and the authors regret these errors.
Figure 2. The neuroprotective effect of the GABAB receptor is dependent on Gi/o-protein and PI3 kinase but independent of intracellular cAMP levels. A, B, Effect of PTX (200 ng/ml; A) and LY294002 (20 mM; B) on the protective effect of baclofen (300 mM) or CGP7930 (50 mM) on apoptotic CGNs (left) and caspase-3 activation (right). For the TUNEL assay, cells were treated with drugs in K5 media for 18–20 h. For caspase-3 activation, cells were treated with drugs in K5 media for 1–12 h. ***p < 0.001, versus K30 conditions. +++p < 0.001, versus the absence of PTX or LY294002. The blots shown are representative of three separate experiments. C, GABAB receptor activation does not induce cAMP production in CGNs. Dose–response effect of baclofen (3 replicates) or adenylyl cyclase activator forskolin (2 replicates) on cAMP production. No error bars were shown for the forskolin experiment, which was used as a control, due to the small sample size. As such, no statistical analysis was performed to determine if a significant difference was present between the two experiments, which does not affect any conclusions in this study.
Figure 3.
Figure 4.
Figure 5.
Figure 7.
