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Zhang C, Wu S, Li M, Li P, Du X, Wang Y, Wang X. Dissecting the chiral recognition of TLR4/MD2 with Neoseptin-3 enantiomers by molecular dynamics simulations. Phys Chem Chem Phys 2024; 26:9309-9316. [PMID: 38426248 DOI: 10.1039/d3cp06124h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Toll-like receptor 4 (TLR4) is a pivotal innate immune recognition receptor that regulates intricate signaling pathways within the immune system. Neoseptin-3 (Neo-3), a recently identified small-molecule agonist for mouse TLR4/MD2, exhibits chiral recognition properties. Specifically, the L-enantiomer of Neo-3 (L-Neo-3) effectively activates the TLR4 signaling pathway, while D-Neo-3 fails to induce TLR4 activation. However, the underlying mechanism by which TLR4 enantioselectively recognizes Neo-3 enantiomers remains poorly understood. In this study, in silico simulations were performed to investigate the mechanism of chiral recognition of Neo-3 enantiomers by TLR4/MD2. Two L-Neo-3 molecules stably resided within the cavity of MD2 as a dimer, and the L-Neo-3 binding stabilized the (TLR4/MD2)2 dimerization state. However, the strong electrostatic repulsion between the hydrogen atoms on the chiral carbon of D-Neo-3 molecules caused the relative positions of two D-Neo-3 molecules to continuously shift during the simulation process, thus preventing the formation of D-Neo-3 dimer as well as their stable interactions with the surrounding residues in (TLR4/MD2)2. Considering that L-Neo-3 could not sustain a stable dimeric state in the bulk aqueous environment, it is unlikely that L-Neo-3 entered the cavity of MD2 as a dimeric unit. Umbrella sampling simulations revealed that the second L-Neo-3 molecule entering the cavity of MD2 exhibited a lower binding energy (-25.75 kcal mol-1) than that of the first L-Neo-3 molecule (-14.31 kcal mol-1). These results imply that two L-Neo-3 molecules enter the cavity of MD2 sequentially, with the binding of the first L-Neo-3 molecule facilitating the entry of the second one. This study dissects the binding process of Neo-3 enantiomers, offering a comprehensive understanding of the atomic-level mechanism underlying TLR4's chiral recognition of Neo-3 molecules.
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Affiliation(s)
- Cong Zhang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China.
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Siru Wu
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China.
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Mingqi Li
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China.
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Penghui Li
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China
| | - Xiubo Du
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China
| | - Yibo Wang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China.
| | - Xiaohui Wang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China.
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, 230026, China
- Beijing National Laboratory for Molecular Sciences, Beijing, 100190, China
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Cicchinelli S, Pignataro G, Gemma S, Piccioni A, Picozzi D, Ojetti V, Franceschi F, Candelli M. PAMPs and DAMPs in Sepsis: A Review of Their Molecular Features and Potential Clinical Implications. Int J Mol Sci 2024; 25:962. [PMID: 38256033 PMCID: PMC10815927 DOI: 10.3390/ijms25020962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 12/31/2023] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
Sepsis is a serious organ dysfunction caused by a dysregulated immune host reaction to a pathogen. The innate immunity is programmed to react immediately to conserved molecules, released by the pathogens (PAMPs), and the host (DAMPs). We aimed to review the molecular mechanisms of the early phases of sepsis, focusing on PAMPs, DAMPs, and their related pathways, to identify potential biomarkers. We included studies published in English and searched on PubMed® and Cochrane®. After a detailed discussion on the actual knowledge of PAMPs/DAMPs, we analyzed their role in the different organs affected by sepsis, trying to elucidate the molecular basis of some of the most-used prognostic scores for sepsis. Furthermore, we described a chronological trend for the release of PAMPs/DAMPs that may be useful to identify different subsets of septic patients, who may benefit from targeted therapies. These findings are preliminary since these pathways seem to be strongly influenced by the peculiar characteristics of different pathogens and host features. Due to these reasons, while initial findings are promising, additional studies are necessary to clarify the potential involvement of these molecular patterns in the natural evolution of sepsis and to facilitate their transition into the clinical setting.
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Affiliation(s)
- Sara Cicchinelli
- Department of Emergency, S.S. Filippo e Nicola Hospital, 67051 Avezzano, Italy;
| | - Giulia Pignataro
- Department of Emergency, Anesthesiological and Reanimation Sciences, Fondazione Policlinico Universitario Agostino Gemelli—IRRCS, Università Cattolica del Sacro Cuore, 00168 Roma, Italy; (G.P.); (S.G.); (A.P.); (D.P.); (V.O.); (F.F.)
| | - Stefania Gemma
- Department of Emergency, Anesthesiological and Reanimation Sciences, Fondazione Policlinico Universitario Agostino Gemelli—IRRCS, Università Cattolica del Sacro Cuore, 00168 Roma, Italy; (G.P.); (S.G.); (A.P.); (D.P.); (V.O.); (F.F.)
| | - Andrea Piccioni
- Department of Emergency, Anesthesiological and Reanimation Sciences, Fondazione Policlinico Universitario Agostino Gemelli—IRRCS, Università Cattolica del Sacro Cuore, 00168 Roma, Italy; (G.P.); (S.G.); (A.P.); (D.P.); (V.O.); (F.F.)
| | - Domitilla Picozzi
- Department of Emergency, Anesthesiological and Reanimation Sciences, Fondazione Policlinico Universitario Agostino Gemelli—IRRCS, Università Cattolica del Sacro Cuore, 00168 Roma, Italy; (G.P.); (S.G.); (A.P.); (D.P.); (V.O.); (F.F.)
| | - Veronica Ojetti
- Department of Emergency, Anesthesiological and Reanimation Sciences, Fondazione Policlinico Universitario Agostino Gemelli—IRRCS, Università Cattolica del Sacro Cuore, 00168 Roma, Italy; (G.P.); (S.G.); (A.P.); (D.P.); (V.O.); (F.F.)
| | - Francesco Franceschi
- Department of Emergency, Anesthesiological and Reanimation Sciences, Fondazione Policlinico Universitario Agostino Gemelli—IRRCS, Università Cattolica del Sacro Cuore, 00168 Roma, Italy; (G.P.); (S.G.); (A.P.); (D.P.); (V.O.); (F.F.)
| | - Marcello Candelli
- Department of Emergency, Anesthesiological and Reanimation Sciences, Fondazione Policlinico Universitario Agostino Gemelli—IRRCS, Università Cattolica del Sacro Cuore, 00168 Roma, Italy; (G.P.); (S.G.); (A.P.); (D.P.); (V.O.); (F.F.)
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