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Li X, Chen T, Wu X, Jiang X, Luo P, E Z, Hu C, Ren C. Apoptosis-Inducing Factor 2 (AIF-2) Mediates a Caspase-Independent Apoptotic Pathway in the Tropical Sea Cucumber ( Holothuria leucospilota). Int J Mol Sci 2022; 23:ijms23063008. [PMID: 35328428 PMCID: PMC8954137 DOI: 10.3390/ijms23063008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/02/2022] [Accepted: 03/07/2022] [Indexed: 11/16/2022] Open
Abstract
Apoptosis, also known as programmed cell death, is a biological process that is critical for embryonic development, organic differentiation, and tissue homeostasis of organisms. As an essential mitochondrial flavoprotein, the apoptosis-inducing factor (AIF) can directly mediate the caspase-independent mitochondrial apoptotic pathway. In this study, we identified and characterized a novel AIF-2 (HlAIF-2) from the tropical sea cucumber Holothuria leucospilota. HlAIF-2 contains a conserved Pyr_redox_2 domain and a putative C-terminal nuclear localization sequence (NLS) but lacks an N-terminal mitochondrial localization sequence (MLS). In addition, both NADH- and FAD-binding domains for oxidoreductase function are conserved in HlAIF-2. HlAIF-2 mRNA was ubiquitously detected in all tissues and increased significantly during larval development. The transcript expression of HlAIF-2 was significantly upregulated after treatment with CdCl2, but not the pathogen-associated molecular patterns (PAMPs) in primary coelomocytes. In HEK293T cells, HlAIF-2 protein was located in the cytoplasm and nucleus, and tended to transfer into the nucleus by CdCl2 incubation. Moreover, there was an overexpression of HlAIF-2-induced apoptosis in HEK293T cells. As a whole, this study provides the first evidence for heavy metal-induced apoptosis mediated by AIF-2 in sea cucumbers, and it may contribute to increasing the basic knowledge of the caspase-independent apoptotic pathway in ancient echinoderm species.
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Affiliation(s)
- Xiaomin Li
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; (X.L.); (T.C.); (X.J.); (P.L.); (Z.E.); (C.H.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ting Chen
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; (X.L.); (T.C.); (X.J.); (P.L.); (Z.E.); (C.H.)
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510301, China
| | - Xiaofen Wu
- Institute for Integrative Biology of the Cell, University of Paris-Saclay, 91198 Paris, France;
| | - Xiao Jiang
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; (X.L.); (T.C.); (X.J.); (P.L.); (Z.E.); (C.H.)
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510301, China
| | - Peng Luo
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; (X.L.); (T.C.); (X.J.); (P.L.); (Z.E.); (C.H.)
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510301, China
| | - Zixuan E
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; (X.L.); (T.C.); (X.J.); (P.L.); (Z.E.); (C.H.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chaoqun Hu
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; (X.L.); (T.C.); (X.J.); (P.L.); (Z.E.); (C.H.)
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510301, China
| | - Chunhua Ren
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; (X.L.); (T.C.); (X.J.); (P.L.); (Z.E.); (C.H.)
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510301, China
- Correspondence:
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