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Li ZC, Wang LL, Zhao YS, Peng DJ, Chen J, Jiang SY, Zhao L, Aschner M, Li SJ, Jiang YM. Sodium para-aminosalicylic acid ameliorates lead-induced hippocampal neuronal apoptosis by suppressing the activation of the IP 3R-Ca 2+-ASK1-p38 signaling pathway. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 241:113829. [PMID: 36068756 PMCID: PMC9452829 DOI: 10.1016/j.ecoenv.2022.113829] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/25/2022] [Accepted: 06/27/2022] [Indexed: 05/10/2023]
Abstract
Lead (Pb) is a naturally occurring heavy metal, which can damage the brain and affect learning and memory. Sodium para-aminosalicylic acid (PAS-Na), a non-steroidal anti-inflammatory drug, can readily cross the blood-brain barrier. Our previous studies have found that PAS-Na alleviated Pb-induced hippocampal ultrastructural damage and neurodegeneration, but the mechanism has yet to be defined. Here, we investigated the molecular mechanisms that mediate Pb-induced apoptosis in hippocampal neurons, and the efficacy of PAS-Na in alleviating its effects. This work showed that juvenile developmental Pb exposure impaired rats cognitive ability by inducing apoptotic cell death in hippocampal neurons. Pb-induced neuronal apoptosis was accompanied by increased inositol 1,4,5-trisphosphate receptor (IP3R) expression and enhanced intracellular calcium [Ca2+]i levels, which resulted in increased phosphorylation of neuronal apoptosis signal-regulating kinase 1 (ASK1) and p38. Activation of ASK1 and p38 was blocked by IP3R inhibitor and a Ca2+ chelator. Importantly, PAS-Na treatment improved the Pb-induced effects on cognitive deficits in rats, concomitant with rescued neuronal apoptosis. In addition, PAS-Na reduced the expression of IP3R and the ensuing increase in intracellular Ca2+ and decreased the phosphorylation of ASK1 and p38 in Pb-exposed neurons. Taken together, this study demonstrates that the IP3R-Ca2+-ASK1-p38 signaling pathway mediates Pb-induced apoptosis in hippocampal neurons, and that PAS-Na, at a specific dose-range, ameliorates these changes. Collectively, this study sheds novel light on the cellular mechanisms that mediate PAS-Na efficacy, laying the groundwork for future research to examine the treatment potential of PAS-Na upon Pb poisoning.
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Affiliation(s)
- Zhao-Cong Li
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Lei-Lei Wang
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Yue-Song Zhao
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Dong-Jie Peng
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Jing Chen
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Si-Yang Jiang
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Lin Zhao
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Shao-Jun Li
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China.
| | - Yue-Ming Jiang
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, China.
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Stable expression and function of the inositol 1,4,5-triphosphate receptor requires palmitoylation by a DHHC6/selenoprotein K complex. Proc Natl Acad Sci U S A 2014; 111:16478-83. [PMID: 25368151 DOI: 10.1073/pnas.1417176111] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Calcium (Ca(2+)) is a secondary messenger in cells and Ca(2+) flux initiated from endoplasmic reticulum (ER) stores via inositol 1,4,5-triphosphate (IP3) binding to the IP3 receptor (IP3R) is particularly important for the activation and function of immune cells. Previous studies demonstrated that genetic deletion of selenoprotein K (Selk) led to decreased Ca(2+) flux in a variety of immune cells and impaired immunity, but the mechanism was unclear. Here we show that Selk deficiency does not affect receptor-induced IP3 production, but Selk deficiency through genetic deletion or low selenium in culture media leads to low expression of the IP3R due to a defect in IP3R palmitoylation. Bioinformatic analysis of the DHHC (letters represent the amino acids aspartic acid, histidine, histidine, and cysteine in the catalytic domain) family of enzymes that catalyze protein palmitoylation revealed that one member, DHHC6, contains a predicted Src-homology 3 (SH3) domain and DHHC6 is localized to the ER membrane. Because Selk is also an ER membrane protein and contains an SH3 binding domain, immunofluorescence and coimmunoprecipitation experiments were conducted and revealed DHHC6/Selk interactions in the ER membrane that depended on SH3/SH3 binding domain interactions. DHHC6 knockdown using shRNA in stably transfected cell lines led to decreased expression of the IP3R and impaired IP3R-dependent Ca(2+) flux. Mass spectrophotometric and bioinformatic analyses of the IP3R protein identified two palmitoylated cysteine residues and another potentially palmitoylated cysteine, and mutation of these three cysteines to alanines resulted in decreased IP3R palmitoylation and function. These findings reveal IP3R palmitoylation as a critical regulator of Ca(2+) flux in immune cells and define a previously unidentified DHHC/Selk complex responsible for this process.
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Akl H, Vervloessem T, Kiviluoto S, Bittremieux M, Parys JB, De Smedt H, Bultynck G. A dual role for the anti-apoptotic Bcl-2 protein in cancer: mitochondria versus endoplasmic reticulum. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2240-52. [PMID: 24768714 DOI: 10.1016/j.bbamcr.2014.04.017] [Citation(s) in RCA: 151] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/04/2014] [Accepted: 04/05/2014] [Indexed: 12/14/2022]
Abstract
Anti-apoptotic Bcl-2 contributes to cancer formation and progression by promoting the survival of altered cells. Hence, it is a prime target for novel specific anti-cancer therapeutics. In addition to its canonical anti-apoptotic role, Bcl-2 has an inhibitory effect on cell-cycle progression. Bcl-2 acts at two different intracellular compartments, the mitochondria and the endoplasmic reticulum (ER). At the mitochondria, Bcl-2 via its hydrophobic cleft scaffolds the Bcl-2-homology (BH) domain 3 (BH3) of pro-apoptotic Bcl-2-family members. Small molecules (like BH3 mimetics) can disrupt this interaction, resulting in apoptotic cell death in cancer cells. At the ER, Bcl-2 modulates Ca(2+) signaling, thereby promoting proliferation while increasing resistance to apoptosis. Bcl-2 at the ER acts via its N-terminal BH4 domain, which directly binds and inhibits the inositol 1,4,5-trisphosphate receptor (IP3R), the main intracellular Ca(2+)-release channel. Tools targeting the BH4 domain of Bcl-2 reverse Bcl-2's inhibitory action on IP3Rs and trigger pro-apoptotic Ca(2+) signaling in cancer B-cells, including chronic lymphocytic leukemia (CLL) cells and diffuse large B-cell lymphoma (DLBCL) cells. The sensitivity of DLBCL cells to BH4-domain targeting tools strongly correlated with the expression levels of the IP3R2 channel, the IP3R isoform with the highest affinity for IP3. Interestingly, bio-informatic analysis of a database of primary CLL patient cells also revealed a transcriptional upregulation of IP3R2. Finally, this review proposes a model, in which cancer cell survival depends on Bcl-2 at the mitochondria and/or the ER. This dependence likely will have an impact on their responses to BH3-mimetic drugs and BH4-domain targeting tools. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.
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Affiliation(s)
- Haidar Akl
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Medicine, Campus Gasthuisberg, O/N-I, Bus 802, Herestraat 49, BE-3000 Leuven, Belgium.
| | - Tamara Vervloessem
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Medicine, Campus Gasthuisberg, O/N-I, Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Santeri Kiviluoto
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Medicine, Campus Gasthuisberg, O/N-I, Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Mart Bittremieux
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Medicine, Campus Gasthuisberg, O/N-I, Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Jan B Parys
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Medicine, Campus Gasthuisberg, O/N-I, Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Humbert De Smedt
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Medicine, Campus Gasthuisberg, O/N-I, Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Medicine, Campus Gasthuisberg, O/N-I, Bus 802, Herestraat 49, BE-3000 Leuven, Belgium.
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