Fructose Mediated Non-Alcoholic Fatty Liver Is Attenuated by HO-1-SIRT1 Module in Murine Hepatocytes and Mice Fed a High Fructose Diet
Authors: Charles Meadows
Gaia Favero
Nader G Abraham
Nitin Puri
Hayden Ansinelli
Sarah Stevens
Komal Sodhi
Rita Rezzani
Joseph I Shapiro
Edward Lebovics
Journal: PLoS ONE (2015)
Discipline: Multidisciplinary
Keywords: Oxidative stress; Nonalcoholic fatty liver disease (NAFLD); Obesity; Cardiovascular disease (CVD); Heme Oxygenase-1 (HO-1)
Affiliations: Departments of Medicine and Surgery, Joan C. Edwards School of Medicine, Marshall University, Huntington, West Virginia, United States of America., Department of Physiology & Pharmacology, University of Toledo College of Medicine, Toledo, Ohio, United States of America., Department of Clinical and Experimental Sciences, Division of Anatomy and Physiopathology, University of Brescia, Brescia, Italy., Departments of Medicine and Gastroenterology, New York Medical College, Valhalla, New York, United States of America.

Abstract:  Background: Oxidative stress underlies the etiopathogenesis of nonalcoholic fatty liver disease (NAFLD), obesity and cardiovascular disease (CVD). Heme Oxygenase-1 (HO-1) is a potent endogenous antioxidant gene that plays a key role in decreasing oxidative stress. Sirtuin1 (SIRT1) belongs to the family of NAD-dependent de-acyetylases and is modulated by cellular redox. Hypothesis: We hypothesize that fructose-induced obesity creates an inflammatory and oxidative environment conducive to the development of NAFLD and metabolic syndrome. The aim of this study is to determine whether HO-1 acts through SIRT1 to form a functional module within hepatocytes to attenuate steatohepatitis, hepatic fibrosis and cardiovascular dysfunction. Methods and results: We examined the effect of fructose, on hepatocyte lipid accumulation and fibrosis in murine hepatocytes and in mice fed a high fructose diet in the presence and absence of CoPP, an inducer of HO-1, and SnMP, an inhibitor of HO activity. Fructose increased oxidative stress markers and decreased HO-1 and SIRT1 levels in hepatocytes (p&lt;0.05). Further fructose supplementation increased FAS, PPARα, pAMPK and triglycerides levels; CoPP negated this increase. Concurrent treatment with CoPP and SIRT1 siRNA in hepatocytes increased FAS, PPARα, pAMPK and triglycerides levels suggesting that HO-1 is upstream of SIRT1 and suppression of SIRT1 attenuates the beneficial effects of HO-1. A high fructose diet increased insulin resistance, blood pressure, markers of oxidative stress and lipogenesis along with fibrotic markers in mice (p&lt;0.05). Increased levels of HO-1 increased SIRT1 levels and ameliorated fructose-mediated lipid accumulation and fibrosis in liver along with decreasing vascular dysfunction (p&lt;0.05 vs. fructose). These beneficial effects of CoPP were reversed by SnMP. Conclusion: Taken together, our study demonstrates, for the first time, that HO-1 induction attenuates fructose-induced hepatic lipid deposition, prevents the development of hepatic fibrosis and abates NAFLD-associated vascular dysfunction; effects that are mediated by activation of SIRT1 gene expression. 

Retracted: Yes

PubPeer comments:
 In figure 7 A, panels b and d overlap as indicated by the boxes. The images clearly come from the same tissue section, but are presented as different experimental treatments. Perhaps the authors can comment.![file] , 
 Except for the labeling, WT vs. lean, the top left pane in figure 4A from the 2015 PLOSone paper is the same as the top left panel in figure 2 from the paper in Obesity in 2014. ![file] The bar graphs in the two figures below the images in the figures are remarkably similar. Similar, even though they are experiment separated in time, performed at different animal facilities and performed with different protocols. It also appears that different, though related, mouse strains may have been used. The 2014 Obesity paper used C57Bl6 (also identified as B6, B6 J and C57BL 6J ), while the 2015 PlosOne paper used, B6v-Lep obese J, a strain derived from C57BL 6. ![file] , 
 The same actin control is shown for treated cultured heptocytes (figure 1A) and livers from treated mice (figure 6A). The two experiments also involve entirely different experimental treatments. The panels are shown as they appeared; the actin lanes are also shown enlarged with the brightness and contrast adjusted to show shared details. This same actin control also appears in figure 6F and figures 8B and 8C. So how can one use the same actin blot for experiments performed with different cells tissues and different experimental treatments? The appearance of this actin control has been noted in five other publications. See comments in: https: pubpeer.com publications 013834175109D0766BBE70E88E2353 ![file] ![file] , 
 The G6Pase panel in figure 6D was constructed by duplicating the first four lanes and rotating the lanes 180 degrees on the horizontal axis. This assemblage of bands has been used in two other publications as indicated in the panels that follow (International Journal of Obesity (2014) and Obesity (2014)). In the paper in International Journal of Obesity the entire assembled panel was rotated 180 degrees on the horizontal axis. The actin panel in the International Journal of Obesity is a duplicate of the actin panel from the PLOS ONE paper. In the paper in Obesity, the panel was rotated 180 degrees on the perpendicular axis; the aspect ratio appears to be altered. The three appearances of this merged duplicate western blot purport to show results with different proteins (G6Pase, mest and pAMPK) and different experimental protocols. The merged bands have been commented on previously. International Journal of Obesity (2014) Figure 6 https: pubpeer.com publications D0737900D02C1DD5D8721FB4B52372 Obesity (Silver Spring, Md.) (2012) Figure 7C https: pubpeer.com publications E865BFC0CEBB2DC7E479846587019D ![file] ![file] ![file] , 
 Would the authors care to comment on the similarity between the AMPK lanes in figure 2A and the actin lanes in figure 6E? The experiment shown in figure 2A used cultured hepatocytes while the experiment shown figure 6E employed mice. ![file] , 
 Retraction: Fructose Mediated Non-Alcoholic Fatty Liver Is Attenuated by HO-1-SIRT1 Module in Murine Hepatocytes and Mice Fed a High Fructose Diet https: journals.plos.org plosone article?id=10.1371 journal.pone.0259219 After this article [1] was published, concerns came to light involving data reported in Figs 1, 4, 6, 7 and 8. The concerns include both similarities across figure panels within this article [1], and similarities between blot images in [1] and blot images reported in other articles [2u201311]. In many cases, the similar data represent different experimental results in the different figures and or publications. In light of these issues, PLOS ONE has concerns about the integrity and reliability of the results and conclusions reported in [1]. The corresponding author requested retraction of this article. They stated that data underlying some of the articleu2019s results are currently held by Marshall University, and that the original data underlying Figs 4A and 7A are not available. Due to the extensive image concerns and the authoru2019s comments regarding data availability, PLOS ONE concluded that the results and conclusions reported in the article are not reliable. Therefore, the PLOS ONE Editors retract this article. The articleu2019s authors either could not be reached or did not respond directly to comment on the retraction decision. The following figure panels in [1] appear similar to material in other published articles [2u201311]. References 2, 3, and 6u201311 were published prior to [1] and by different author groups, although some authors overlap with [1]; four of the prior articles [7, 8, 10, 11] are not offered as Open Access articles under a Creative Commons license. For these reasons, the figure panels in [1] that are similar to content in [2, 3, 6u201311] are excluded from the PLOS ONE articleu2019s [1] license. At the time of retraction, the PLOS ONE article [1] was republished to note these exclusions in the figure legends and copyright statement. Readers should refer to the indicated publications for the copyright notices. Actin blot in Fig 1E of [1]: similar to previously published content in [11] Actin blots in Fig 1F, 6A, 6F, 8B, 8C of [1]: similar to one another and previously published content in [2u2013 6, 9, 10] Actin blots in Figs 6B and 7C of [1]: similar to one another and previously published content in [3, 5] Actin blot in Fig 6D of [1]: similar to previously published content in [3, 7u20139] Actin blot in Fig 7D: similar to content published in [5] Actin blot in Fig 8A of [1]: similar to previously published content in [4, 11] Fig 1E SIRT1 and Fig 6E FAS panels in [1]: similar to one another and previously published content in [4, 10] AMPK panel in Fig 2A and Actin blot in Fig 6E of [1]: similar to one another and previously published content in [4, 10] Top left panel (WT) in Fig 4A of [1]: similar to previously published content in [6] G6Pase in Fig 6D of [1]: similar to previously published content in [3, 11] Note, the article cited in this notice as Ref. 11 was retracted in 2021; see [12] for the retraction notice. , 
 https: retractionwatch.com 2022 06 08 medical-school-dean-up-to-five-retractions https: forbetterscience.com 2021 04 13 the-intellectual-leaps-of-joe-shapiro ,