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Dattaroy D, Seth RK, Sarkar S, Kimono D, Albadrani M, Chandrashekaran V, Al Hasson F, Singh UP, Fan D, Nagarkatti M, Nagarkatti P, Diehl AM, Chatterjee S. Sparstolonin B (SsnB) attenuates liver fibrosis via a parallel conjugate pathway involving P53-P21 axis, TGF-beta signaling and focal adhesion that is TLR4 dependent. Eur J Pharmacol 2018; 841:33-48. [PMID: 30194936 PMCID: PMC7193950 DOI: 10.1016/j.ejphar.2018.08.040] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 08/29/2018] [Accepted: 08/30/2018] [Indexed: 02/07/2023]
Abstract
SsnB previously showed a promising role to lessen liver inflammation observed in a mouse model of NAFLD. Since NAFLD can progress to fibrosis, studies were designed to unravel its role in attenuating NAFLD associated fibrosis. Using both in vivo and in vitro approaches, the study probed the possible mechanisms that underlined the role of SsnB in mitigating fibrosis. Mechanistically, SsnB, a TLR4 antagonist, decreased TLR4-PI3k akt signaling by upregulating PTEN protein expression. It also decreased MDM2 protein activation and increased p53 and p21 gene and protein expression. SsnB also downregulated pro-fibrogenic hedgehog signaling pathway, inhibited hepatic stellate cell proliferation and induced apoptosis in hepatic stellate cells, a mechanism that was LPS dependent. Further, SsnB decreased fibrosis by antagonizing TLR4 induced TGFβ signaling pathway. Alternatively, SsnB augmented BAMBI (a TGFβ pseudo-receptor) expression in mice liver by inhibiting TLR4 signaling pathway and thus reduced TGFβ signaling, resulting in decreased hepatic stellate cell activation and extracellular matrix deposition. In vitro experiments on human hepatic stellate cell line showed that SsnB increased gene and protein expression of BAMBI. It also decreased nuclear co-localization of phospho SMAD2/3 and SMAD4 protein and thus attenuated TGFβ signaling in vitro. We also observed a significant decrease in phosphorylation of SMAD2/3 protein, decreased STAT3 activation, alteration of focal adhesion protein and stress fiber disassembly upon SsnB administration in hepatic stellate cells which further confirmed the antagonistic effect of SsnB on TLR4-induced fibrogenesis.
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Affiliation(s)
- Diptadip Dattaroy
- Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, United States
| | - Ratanesh Kumar Seth
- Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, United States
| | - Sutapa Sarkar
- Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, United States
| | - Diana Kimono
- Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, United States
| | - Muayad Albadrani
- Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, United States
| | - Varun Chandrashekaran
- Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, United States
| | - Firas Al Hasson
- Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, United States
| | - Udai P. Singh
- Department of Pathology Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, SC 29208, United States
| | - Daping Fan
- Department of Cell Biology and Anatomy, School of Medicine, USC, Columbia, SC, United States
| | - Mitzi Nagarkatti
- Department of Pathology Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, SC 29208, United States
| | - Prakash Nagarkatti
- Department of Pathology Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, SC 29208, United States
| | - Anna Mae Diehl
- Division of Gastroenterology, Duke University, Durham 27707, United States
| | - Saurabh Chatterjee
- Environmental Health and Disease Laboratory, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, United States.
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