[Retracted] Hyperglycemia Induces Toll-Like Receptor-2 and -4 Expression and Activity in Human Microvascular Retinal Endothelial Cells: Implications for Diabetic Retinopathy

Hindawi Journal of Diabetes Research Volume 2020, Article ID 5071954, 1 page https://doi.org/10.1155/2020/5071954 Retraction Retracted: Hyperglycemia Induces Toll-Like Receptor-2 and -4 Expression and Activity in Human Microvascular Retinal Endothelial Cells: Implications for Diabetic Retinopathy Journal of Diabetes Research Received 24 September 2020; Accepted 24 September 2020; Published 31 October 2020 Copyright © 2020 Journal of Diabetes Research. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Journal of Diabetes Research has retracted the article titled “Hyperglycemia Induces Toll-Like Receptor-2 and -4 Expression and Activity in Human Microvascular Retinal Endothelial Cells: Implications for Diabetic Retinopathy” [1] due to concerns identified with Figures 1 and 2. Following the publication of an erratum to correct an image duplication in Figure 2 [2], concerns have been identified in the original publication, and in the revised figure provided by the authors. Our concerns are as follows: Figure 1(a) (i) GADPH bands C and 15 are the same as bands 25 and M (horizontally flipped). (ii) In the TLR4 bands, there is an undeclared gel splice between the C and 15 bands Figure 1(b) (i) There is an undeclared gel splice between the 25 and M lanes of TLR4 which is not consistent with the loading control Figure 2(c) (i) There is an undeclared gel splice between the C and 15 lanes of TRIF and IRF3 (ii) There is an undeclared gel splice between the 25 and M lanes of TRIF and IRF3 (iii) These gel splices are not consistent with the loading control With the agreement with the Chief Editor, this article is therefore being retracted due to the above concerns. References [1] U. Rajamani and I. Jialal, “Hyperglycemia Induces Toll-Like Receptor-2 and -4 Expression and Activity in Human Microvascular Retinal Endothelial Cells: Implications for Diabetic Retinopathy,” Journal of Diabetes Research, vol. 2014, Article ID 790902, 15 pages, 2014. [2] U. Rajamani and I. Jialal, “Erratum to “Hyperglycemia Induces Toll-Like Receptor-2 and -4 Expression and Activity in Human Microvascular Retinal Endothelial Cells: Implications for Diabetic Retinopathy”,” Journal of Diabetes Research, vol. 2016, Article ID 8976945, 2 pages, 2016. ED Hindawi Publishing Corporation Journal of Diabetes Research Volume 2014, Article ID 790902, 15 pages http://dx.doi.org/10.1155/2014/790902 CT Research Article Hyperglycemia Induces Toll-Like Receptor-2 and -4 Expression and Activity in Human Microvascular Retinal Endothelial Cells: Implications for Diabetic Retinopathy Uthra Rajamani1 and Ishwarlal Jialal1,2 1 Laboratory for Atherosclerosis and Metabolic Research, Division of Endocrinology, Diabetes and Metabolism, Department of Pathology, University of California Davis Medical Center, Research Building 1, Room 3000, 4635 Second Avenue, Sacramento, CA 95817, USA 2 Veterans Affairs Medical Center, Mather, CA 95655, USA Correspondence should be addressed to Ishwarlal Jialal; TR A Received 31 October 2014; Accepted 10 December 2014; Published 31 December 2014 Academic Editor: Subrata Chakrabarti Copyright © 2014 U. Rajamani and I. Jialal. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. RE Diabetic retinopathy (DR) causes visual impairment in working age adults and hyperglycemia-mediated inflammation is central in DR. Toll-like receptors (TLRs) play a key role in innate immune responses and inflammation. However, scanty data is available on their role in DR. Hence, in this study, we examined TLR2 and TLR4 mRNA and protein expression and activity in hyperglycemic human retinal endothelial cells (HMVRECs). HMVRECs were treated with hyperglycemia (HG) or euglycemia and mRNA and protein levels of TLR-2, TLR-4, MyD88, IRF3, and TRIF as well as NF-𝜅B p65 activation were measured. IL-8, IL-1𝛽, TNF-𝛼 and MCP-1, ICAM-1, and VCAM-1 as well as monocyte adhesion to HMVRECs were also assayed. HG (25 mM) significantly induced TLR2 and TLR4 mRNA and protein in HMVRECs. It also increased both MyD88 and non-MyD88 pathways, nuclear factor-𝜅B (NF𝜅B), biomediators, and monocyte adhesion. This inflammation was attenuated by TLR-4 or TLR-2 inhibition, and dual inhibition by a TLR inhibitory peptide as well as TLR2 and 4 siRNA. Additionally, antioxidant treatment reduced TLR-2 and TLR4 expression and downstream inflammatory markers. Collectively, our novel data suggest that hyperglycemia induces TLR-2 and TLR-4 activation and downstream signaling mediating increased inflammation possibly via reactive oxygen species (ROS) and could contribute to DR. 1. Introduction Diabetes is a growing global epidemic affecting nearly 36 million people in USA alone and nearly 350 million worldwide. Diabetic retinopathy (DR) is the leading cause of vision impairment and blindness among working adults and afflicts around 30 percent of patients [1, 2]. Diabetes is a proinflammatory state characterized by elevated levels of C-reactive protein (CRP), inflammatory cytokines, chemokines, adhesion molecules, monocyte activity, and adipose tissue dysregulation [3–6]. Hyperglycemia in diabetes contributes to microvascular complications and reduction of glycemia reduces progression of microvascular disease such as retinopathy [1, 2]. Mechanisms that have been advanced to explain how hyperglycemia can induce DR include the polyol pathway, activation of protein kinase-C (PKC), increased oxidative stress, advanced glycation end product (AGE) formation, and increased inflammation [2, 7–9]. Also both increased oxidative stress and AGE receptor engagement can result in increased inflammation. Several studies have reported a role for inflammation in the development of DR [2, 7–10]. Inflammation results in an increase in NF-𝜅B activity, cytokines, chemokines, adhesion molecules, leukocyte adhesion, and leukostasis [2, 9, 10]. However the exact mechanism behind hyperglycemia-mediated inflammation leading to microvascular complications is unclear. Toll-like receptors (TLRs) are pathogen-associated molecular pattern receptors and play a role in innate immune 2 Journal of Diabetes Research The cells were replaced in complete media and allowed to settle for 24 hours. Subsequently cells were serum starved for 2 hours and HG treatments given as explained above. ED 2.4. Western Blot. Cell lysates (50 𝜇g protein) were resolved, transferred, and probed with TLR-4, TLR-2, myeloid differentiation factor 88 (MyD88), TRIF, and IRF3 antibodies as described previously [22]. Stripped membranes were used for 𝛽-actin as a loading control. Representative blots from four different experiments were used for analysis and in figures a representative b (...truncated)