Toxoplasma gondii inhibits apoptosis via a novel STAT3-miR-17–92-Bim pathway in macrophages
Authors: Zhaorong Lun
Fangli Lu
Xiucai Xu
Yong Wang
He Chen
Aimei Zhang
Yihong Cai
Yuanyuan Tang
Xuwei Mo
Jilong Shen
Journal: Cellular Signalling (2014)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: Apoptosis; Bim; Macrophage; MicroRNA; STAT3.
Affiliations: Anhui Provincial Laboratories of Pathogen Biology and Zoonoses, Anhui Medical University, Hefei, China; Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei, China; Department of Immunology, Anhui Medical University, Hefei, China., Anhui Provincial Laboratories of Pathogen Biology and Zoonoses, Anhui Medical University, Hefei, China; Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China., Anhui Provincial Laboratories of Pathogen Biology and Zoonoses, Anhui Medical University, Hefei, China., Anhui Provincial Laboratories of Pathogen Biology and Zoonoses, Anhui Medical University, Hefei, China; The Central Laboratory of Affiliated Provincial Hospital, Anhui Medical University, Hefei, China., State Key Laboratory of Biocontrol, School of Life Sciences, and Key Laboratory of Tropical Diseases Control, The Ministry of Education, Zhongshan Medical College, China; Department of Pathogen Biology, Sun Yat-Sen University, Guangzhou, China., Department of Pathogen Biology, Nanjing Medical University, Nanjing, China., Anhui Provincial Laboratories of Pathogen Biology and Zoonoses, Anhui Medical University, Hefei, China. Electronic address: .

Abstract:  In order to accomplish their life cycles, intracellular pathogens, including the apicomplexan Toxoplasma gondii, subvert the innate apoptotic response of infected host cells. However, the precise mechanisms of parasite interference with the apoptotic pathway remain unclear. MicroRNAs (miRNAs) regulate gene expression at the posttranscriptional level. Using T. gondii strain TgCtwh3, which was isolated from felids and possesses the predominant genotype China 1 (ToxoDB(#)9) in China, we analyzed the miRNA expression profile of human macrophages challenged with TgCtwh3. The results showed that miR-17-92 miRNA expression was significantly increased and Bim was decreased in TgCtwh3-infected cells. Database analysis of miR-17-92 miRNAs revealed the potential binding sites in the 3'UTR of Bim, one of the crucial effectors of pro-apoptosis. Furthermore, we demonstrated that the promoter of the miR-17-92 gene cluster which encodes miRNAs was transactivated through the promoter binding of the STAT3 following TgCtwh3 infection. Taken together, we describe a novel STAT3-miR-17-92-Bim pathway, thus providing a mechanistic explanation for inhibition of apoptosis of host cells following Toxoplasma infection. 

Retracted: No

PubPeer comments:
 Figure 1A. * Blue boxes: Two of the 0h panels appear to look identical * Green boxes: The top right quadrants of two of the right column panels look more similar than expected ![file] , 
 Figures 3B and 4F: * Red boxes: Three lanes of the GAPDH panel in Figure 3B look remarkably similar to three lanes in the GAPDH panel of Figure 4F, where they represent a very different experiment. ![file] , 
 Figure 1A, revisited after Twitter users suggested there might be more similarities. ![file] , 
 Dear Dr.Bik, Thank you for bringing this issue to our attention. As soon as we received the message,we checked the original data of the experiments. After carefully checking the data we realized there were some of the pictures that do not match during the preparation of these panels. After taking FCM and Western blotting data ,there were many similar original image needed further processing. In the processing, we made a mistake in arranging the images. We sincerely apologize for these mistakes. 1.Blue boxes: We used the only one graph to determinate the results.Because two of the 0h panels are the same sample without treatment. At the 0h of control and TgCtwh3 infection group,they are all cultured in the same bottle,we harvested the cells to detect.Then we separated them into two groups,one of them was infected with TgCtwh3.Maybe it would be more appropriate to separate them at first to detect. 2.When I prepared for representative images in Fig3B and 4F, I had inadvertently misused the GAPDH of them. however, The results of TgCtwh3 infected of macrophages were quantified based on the original images as shown below. The error of the representative image does not affect the conclusion of this experiment. We have corrected Fig1A and Fig3B as shown below. The corrected results, we think, have no direct impact on the hypothesis. We will immediately contact the Editor of the Journal to make the correction. Your comments are greatly appreciated. , 
 #4 Dear author, Thanks for responding. I understand that the re-use of the controls between Fig. 3B and 4F was an inadvertent error. And that the identical FACS panels (blue boxes in Fig. 1a, 0h control and 0h TgCtwh3+Stau-) are so by design, as the 0h post-TgCtwh3 infection FACS plot was meant to display the cells pre-infection (?). Your response misses the 5 boxes with different colors in Fig. 1a. The FACS plots for a single treatment share many data points at different treatment times. This shows that these data are very unlikely to be the result of separate experiments; even when re-running a flow cytometry measurement using the same batch of cells one would not obtain this level of correspondence. Can the authors explain why the measurements at different points in time are not independent? [ Click to animate. Control 6h and 12 h, the left two quadrant share a large amount of points. This happens to a lesser extent also in the other two quadrants ] ![file] [ click to animate, TgCtwh3+Stau+ 0h and 24h. Many points in the top-right quadrant are duplicated. The same is true for the top-part of the bottom-left quadrant, though with a shift it seems ] ![file] [ click to animate, TgCtwh3+Stau+ 6h and 12 h ] ![file] ,