Bifidobacterium plays a protective role in TNF-α-induced inflammatory response in Caco-2 cell through NF-κB and p38MAPK pathways
Authors: Shanai Song
Nana Nie
Zipu Li
Yanyan Zhang
Benzhen Wang
Cui Bai
Journal: Molecular and cellular biochemistry (2020)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: Autophagy; BIF; Intestinal immune system; Intestinal microbiota; Kawasaki disease.
Affiliations: Department of Pediatric Cardiology, Nephrology and Rheumatology, The Affiliated Hospital of Qingdao University, Qingdao, 266000, China., Department of Oncology, The Affiliated Hospital of Qingdao University, Qingdao, 266000, China., Department of Neonatal Intensive Care Unit, Qingdao Women and Children's Hospital, No. 6 Tongfu Road, Shibei District, Qingdao, 266034, China., Heart Center, Qingdao Women and Children's Hospital, No. 6 Tongfu Road, Shibei District, Qingdao, 266034, China., Heart Center, Qingdao Women and Children's Hospital, No. 6 Tongfu Road, Shibei District, Qingdao, 266034, China. .

Abstract:  Kawasaki disease is an immune-mediated acute, systemic vasculitis and is the leading cause of acquired heart disease in children in the developed world. Bifidobacterium (BIF) is one of the dominant bacteria in the intestines of humans and many mammals and is able to adjust the intestinal flora disorder. The Caco-2 cell monolayers were treated with tumor necrosis factor-α (TNF-α) at 10 ng/ml for 24 h to induce the destruction of intestinal mucosal barrier system. Cells viability was detected through Cell Counting Kit-8 assay. Cell apoptosis was measured by flow cytometry and the expression of apoptosis related proteins was also detected through Western blot. The level of pro-inflammatory cytokines interleukin-6 (IL-6) and IL-8 was detected through ELISA, Western blot and qRT-PCR, respectively. Transepithelial electrical resistance (TEER) assay was conducted to value the barrier function of intestinal mucosa. Cell autophagy and NF-κB and p38MAPK pathways associated proteins were examined through Western blot. In the absence of TNF-α treatment, cell viability and apoptosis showed no significant change. TNF-α decreased cell viability and increased cell apoptosis and BIF treatment mitigated the TNF-α-induced change. Then, we found that BIF treatment effectively suppressed TNF-α-induced overexpression of IL-6 and IL-8. Besides, the results of TEER assay showed that barrier function of intestinal mucosa which was destroyed by TNF-α was effectively recovered by BIF treatment. In addition, TNF-α induced autophagy was also suppressed by BIF. Moreover, TNF-α activated NF-κB and p38MAPK signal pathways were also blocked by BIF, SN50 and SB203580. Our present study reveals that BIF plays a protective role in TNF-α-induced inflammatory response in Caco-2 cells through NF-κB and p38MAPK pathways. 

Retracted: No

PubPeer comments:
 The Western blots and other figures in this paper have an interesting layout that appears to be shared with many other papers, as discussed in a January 2020 post on Leonid Schneider s blog: https: forbetterscience.com 2020 01 24 the-full-service-paper-mill-and-its-chinese-customers The list of these papers is available here: https: docs.google.com spreadsheets d 1KXqTAyl4j-jVorFPMD2XRpr76LcIKJ0CVyIvRj0exYQ edit?usp=sharing In almost all papers, Western blot panels within the same figure, and across figures and papers, appear to share the same background, while the bands are regularly spaced, all have similar rounded edges without the usual smudges and specks, and with some bands showing a recognizable  jumping sardine shape. Also in almost all papers, bar graphs show a characteristic layout with bars in solid shades of grey, and the left-most bar in black, as well as double-edged error bars. Many papers have  cell viability and  apoptotic cells graphs. In some of these papers, including this one, flow cytometry plot show a unnaturally dense and well defined  hairball of events in Q3 with a few regularly spaced events in Q1 and Q2. To illustrate the recognizable layout of this paper, here is Figure 1 from this paper. ![file] , 
 To illustrate the similarities in the background of the Western blot panels, here are two Figure 5 from this paper, enhanced to bring out the background. Note the similar background in all panels, with e.g. small vertical stripes above the left edges of the first bands from the left. ![file] , 
 To illustrate the unexpected features of the flow cytometry plots, here are panels from Figure 1. ![file] ,