Berberine improves kidney function in diabetic mice via AMPK activation
Authors: Li-Na Sun
Xue-Ling Wang
Hui-Bin Nie
Guang-Ju Guan
Long Zhao
Journal: PLoS ONE (2014)
Discipline: Multidisciplinary
Keywords: Diabetic nephropathy; Berberine; AMP-activated protein kinase (AMPK); kidney function; oxidative stress
Affiliations: Nephrology Research Institute, the Second Hospital of Shandong University, Jinan, Shandong, China.

Abstract:  Diabetic nephropathy is a major cause of morbidity and mortality in diabetic patients. Effective therapies to prevent the development of this disease are required. Berberine (BBR) has several preventive effects on diabetes and its complications. However, the molecular mechanism of BBR on kidney function in diabetes is not well defined. Here, we reported that activation of AMP-activated protein kinase (AMPK) is required for BBR-induced improvement of kidney function in vivo. AMPK phosphorylation and activity, productions of reactive oxygen species (ROS), kidney function including serum blood urea nitrogen (BUN), creatinine clearance (Ccr), and urinary protein excretion, morphology of glomerulus were determined in vitro or in vivo. Exposure of cultured human glomerulus mesangial cells (HGMCs) to BBR time- or dose-dependently activates AMPK by increasing the thr172 phosphorylation and its activities. Inhibition of LKB1 by siRNA or mutant abolished BBR-induced AMPK activation. Incubation of cells with high glucose (HG, 30 mM) markedly induced the oxidative stress of HGMCs, which were abolished by 5-aminoimidazole-4-carboxamide ribonucleoside, AMPK gene overexpression or BBR. Importantly, the effects induced by BBR were bypassed by AMPK siRNA transfection in HG-treated HGMCs. In animal studies, streptozotocin-induced hyperglycemia dramatically promoted glomerulosclerosis and impaired kidney function by increasing serum BUN, urinary protein excretion, and decreasing Ccr, as well as increased oxidative stress. Administration of BBR remarkably improved kidney function in wildtype mice but not in AMPKα2-deficient mice. We conclude that AMPK activation is required for BBR to improve kidney function in diabetic mice. 

Retracted: Yes

PubPeer comments:
 2017 retraction. http: journals.plos.org plosone article?id=10.1371 journal.pone.0190562 , 
 That is an impressive Retraction notice! ------------------------------------- Concerns have been raised that images presented in Figures 1 and 2 of this PLOS ONE article [1] are similar to images in other published works. Several of the figure legends and labels indicate that the images showing similarities represent different experiments. Figure 2A AMPK Western blot in [1] is similar to the following: - Figure 6b GAPDH panel in [2] - Figure 5B GAPDH panel in [3] - Figure 6B GAPDH panel in [4] - Figure 1d AMPK panel in [5] - Figure 1E AMPK panel in [6] - Figure 3A GAPDH panel in [7] - Figure 2B AMPK panels in [8] - Figure 6C AMPK panel in [8] Figure 2A P-AMPK Western blot in [1] is similar to the following: - Figure 1E P-AMPK panel in [6] - Figure 3A p27 kip1 panels in [7] - Figure 2A P-AMPK panel in [8] Figure 2A LKB1 Western blot in [1] is similar to the following: - Figure 5C Occludin panel in [3] - Figure 3a iNOS panel in [5] - Figure 2A LKB1 panels in [8] Figures 1A, 1B and 1C, including Western blots and charts, appear similar in [1] and [8]. Figure 2B P-AMPK and AMPK Western blots in [1] are similar to Figure 2B P-AMPK and AMPK panels, respectively, in [8]. Additionally, there is duplication of some text between the Results section of the PLOS ONE article [1] and the Results sections of [5u20138]. The authors have stated that the Western blots for this article were performed by an external company. Following evaluation of the issues identified and the information provided by the authors, the concerns about the data reported in the article remain. In light of the concerns about the integrity of the data and text overlap, the PLOS ONE Editors retract this article. The corresponding author regrets this situation and extends his apology to the scientific community. We notified the authorsu2019 institution and all co-authors of this retraction. GJG, LZ agreed with the retraction. LNS, HBN, XLW did not respond. References 1.Zhao L, Sun L-N, Nie H-B, Wang X-L, Guan G-J (2014) Berberine Improves Kidney Function in Diabetic Mice via AMPK Activation. PLoS ONE 9(11): e113398. https: doi.org 10.1371 journal.pone.0113398 2.Yu H-Y, Cai Y-B, Liu Z. Activation of AMPK improves lipopolysaccharide-induced dysfunction of the bloodu2013brain barrier in mice. Brain Injury. 2015;29: 777u2013784. pmid:25794165 3.Zhao Z, Hu J, Gao X, Liang H, Liu Z. Activation of AMPK attenuates lipopolysaccharide-impaired integrity and function of bloodu2013brain barrier in human brain microvascular endothelial cells. Experimental and Molecular Pathology. 2014;97: 386u2013392. pmid:25220346 4.Hu M, Liu B. Resveratrol attenuates lipopolysaccharide-induced dysfunction of blood-brain barrier in endothelial cells via AMPK activation. The Korean Journal of Physiology Pharmacology. 2016;20: 325u2013332. [Retraction in: Hu M, Liu B. The Korean Journal of Physiology Pharmacology. 2017;21(2): 277] . pmid:27382348 5.Yang Y, Zhao Z, Liu Y, Kang X, Zhang H, Meng M. Suppression of oxidative stress and improvement of liver functions in mice by ursolic acid via LKB1-AMP-activated protein kinase signaling. Journal of Gastroenterology and Hepatology. 2015;30: 609u2013618. pmid:25168399 6.Jiang Y, Lei J, Feng F, Liang Q, Wang F. Probucol suppresses human glioma cell proliferation in vitro via ROS production and LKB1-AMPK activation. Acta Pharmacologica Sinica. 2014;35: 1556u20131565. pmid:25399650 7.Fan G-H, Wang Z-M, Yang X, Xu L-P, Qin Q, Zhang C, et al. Resveratrol Inhibits Oesophageal Adenocarcinoma Cell Proliferation via AMP-activated Protein Kinase Signaling. Asian Pacific Journal of Cancer Prevention. 2014;15: 677u2013682. Retraction in: Asian Pacific Journal of Cancer Prevention. 2017;18(10): 2895. pmid:24568477 8.Hu M, Liu B. Resveratrol via activation of LKB1-AMPK signaling suppresses oxidative stress to prevent endothelial dysfunction in diabetic mice. Clinical and Experimental Hypertension. 2016;38: 381u2013387. pmid:27149559 -------------------------------------------- As noted, [4] and [7] were already retracted at the time of this Notice. [2] [was subsequently retracted] . [6] [was subsequently retracted] . [8] [was retracted] , leaving [3] and [5] still holding out. , 
 As noted above, Western blots and some other graphs in this paper are strikingly similar to panels found in other, seemingly unrelated papers, with different sets of authors and institutions. These papers might all have been prepared by the same external company, as admitted by the authors in the now retracted paper Long Zhao et al., PLOS ONE (2014), DOl: 10.1371 journal.pone.0113398 - https: pubpeer.com publications 29F5C2BCC1C389A566BB106F3F825C, which is part of this set. For now, I will call this the [External Company Paper Mill.] Multiple papers from this author are also cited in most of the papers in this paper mill. This might suggest that this paper mill might be have set up for citation boosting. All papers in this set (around 20 identified so far) are connected to each other by the same Western blots, graphs, or microscopy photos. Here is Figure 1B from this paper and that of three others in this set. Boxes of the same color highlight immunoblots that look remarkably similar. ![file] , 
 Here is Figure 2A from this paper and from three others in this set. Boxes of the same color highlight immunoblots that look remarkably similar. Note that the Shuangxi Wang et al., Circ Res (2010) is the oldest paper from this set. ![file] ,