Adenosine A2A Receptor Suppressed Astrocyte-Mediated Inflammation Through the Inhibition of STAT3/YKL-40 Axis in Mice With Chronic Cerebral Hypoperfusion-induced White Matter Lesions
Authors: Jie Wang
Lin Chen
Simin Xia
Hong Ran
Linke Zhou
Jialu Huang
Chengjian Feng
Jichao Yuan
Zhenhua Zhou
Xiaofei Hu
Journal: Frontiers in Immunology (2022)
Discipline: IMMUNOLOGY
Keywords: YKL-40; adenosine A2A receptor (ADORA2A); astrocyte; inflammation; white matter lesions.

Abstract:  White matter lesions are an important pathological manifestation of cerebral small vessel disease, with inflammation playing a pivotal role in their development. The adenosine A2a receptor (ADORA2A) is known to inhibit the inflammation mediated by microglia, but its effect on astrocytes is unknown. Additionally, although the level of YKL-40 (expressed mainly in astrocytes) has been shown to be elevated in the model of white matter lesions induced by chronic cerebral hypoperfusion, the specific regulatory mechanism involved is not clear. In this study, we established in vivo and in vitro chronic cerebral hypoperfusion models to explore whether the ADORA2A regulated astrocyte-mediated inflammation through STAT3/YKL-40 axis and using immunohistochemical, western blotting, ELISA, PCR, and other techniques to verify the effect of astrocytes ADORA2A on the white matter injury. The in vivo experiments showed that activation of the ADORA2A decreased the expression of both STAT3 and YKL-40 in the astrocytes and alleviated the white matter injury, whereas its inhibition had the opposite effects. Similarly, ADORA2A inhibition significantly increased the expression of STAT3 and YKL-40 in astrocytes in vitro, with more proinflammatory cytokines being released by astrocytes. STAT3 inhibition enhanced the inhibitory effect of ADORA2A on YKL-40 synthesis, whereas its activation reversed the phenomenon. These results suggest that the activation of ADORA2A in astrocytes can inhibit the inflammation mediated by the STAT3/YKL-40 axis and thereby reduce white matter injury in cerebral small vessel disease. 

Retracted: No

PubPeer comments:
 Dear authors, Could you please check your publication towards the following points: 1) Fig. 1A contains overlapping images (red boxes), though sham samples were taken on 4W and 6W  2) Fig.2A: CCH(WT) Vehicle and CCH(KO) CGS21680 both GFAP and YKL-40 show striking similarity regarding structure, though they are not identical (no image duplication), this raises the question whether the slices are from the same sample.  3) Fig.3A: CCH(WT)SCH58261 and CCH(WT) CGS21680 both GFAP and YKL-40 show striking similarity regarding structure, though they are not identical (no image duplication), this raises the question whether the slices are from the same sample.  , 
 #1 Dear reviewer: Thank you for your comments on this manuscript. Firstly, we sincerely apologize for the mistakes for the pictures. Secondly, we have carried out a comprehensive self-examination for all the experimental data right now. There were some errors when the experimenters were collecting the images. In the figure 1, there are overlapping images in the sham group on 4w and 6w. The reason for this mistake is when drawing the picture, we neglectfully chose a picture from 4W to put in 6W. However, all samples in the sham group were from the normal mice, and the above error did not affect the accuracy of the experiment. In figure 2 and 3, we made a very elementary mistake that the two pictures are the same. The reason for this mistake is the experimenter mindlessly saved the same picture in different folders. In fact, no one would use the same image twice in one article, regardless of any data manipulation. Moreover, we will email the editor for these mistakes and explain reasons and provide the accurate data. If the editorial board accept the reasons, we would like change the wrong pictures into the correct pictures. If the editorial board do not accept the reasons, in order to demonstrate our commitment to the rigor of scientific experiments, we will request withdraw from the editorial board. Ultimately, we must be more careful to avoid the occurrence of such mistakes in future scientific research, so as to pursue the accuracy of experimental results. Hong Ran , 
 **CORRECTION** https: www.frontiersin.org articles 10.3389 fimmu.2022.883172 full *Corrigendum on: full citation of the original version of the article. (provisionally accepted)* *In the original article, it has been brought to the authors attention that there was a mistake in  Figure 1. Activation of ADORA2A reduced white matter injury in the mouse model of CCH induced white matter lesions as published. One image (sham group, 6w) was mistakenly during the figure preparation. The corrected  Figure 1. Activation of ADORA2A reduced white matter injury in the mouse model of CCH induced white matter lesions appears below. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.In the original article, it has been brought to the authors attention that there was a mistake in  Figure 2. Activation of ADORA2A inhibited YKL-40 expression in astrocytes as published. One image (CCH (WT) + Vehicle) was mistakenly duplicated from another image (CCH (KO) + CGS21680) during the figure preparation. The corrected  Figure 2. Activation of ADORA2A inhibited YKL-40 expression in astrocytes appears below. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.In the original article, it has been brought to the authors attention that there was a mistake in  Figure 3. STAT3 was involved in the ADORA2A regulation of YKL-40 expression as published. One image (CCH (WT) + CGS21680) was mistakenly duplicated from another image (CCH (WT) + SCH58261) during the figure preparation. The corrected  Figure 3. STAT3 was involved in the ADORA2A regulation of YKL-40 expression appears below. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.* #2 Thank you for taking quick action in this issue. However, for the record: The issues with Fig.2 and Fig.3 were **NOT image duplications**, as stated in the provisionally accepted corrigendum. As one can see above, the images are clearly not identical, **the sample they were recorded from was the same**. So a potential mistake did not happen during figure preparation but during data acquisition and, to my mind, this has a rather larger impact on data reliability than a  simple mixup during figure items assembling, since we(the readers) cannot check wether something similar happened with data that went into the bar graphs. Therefore that (pro forma) statement  We state that this does not change the scientific conclusions of the article in any way is not very convincing. , 
 Thank you for your further attention for this article. In fact, these samples were continuously sectioned of the same specimen with a thickness of 10-u03bcm, and then one of every three slices was selectedto stain. So we further examined the original data and eliminated the above two similar successive section images. We have check all our original data in this manuscript and no other similar errors were found. In the corrigendum manuscript, we have provided all the original data for the different groups to certify the authenticity of data. And the editorial office of Frontiers in Immunology and handling editor of our manuscript have accepted our corrigendum based on the data we provided. In order to confirm the authenticity of the data, we provide relevant raw data as below. Ultimately, we must be more careful to avoid the occurrence of such mistakes in future scientific research, so as to pursue the accuracy of experimental results. Thank you very much. Orignal data for YKL-40 in the CCH (WT) + Vehicle group and CCH (KO) + CGS21680 group  Orignal data for STAT3 in the CCH (WT) + CGS21680 group and CCH (WT) + SCH58261 group  ,