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Zhang D, Chen X, Liu B, Yuan Y, Cui W, Zhu D, Zhu J, Duan S, Li C. The Temporal and Spatial Changes of Autophagy and PI3K Isoforms in Different Neural Cells After Hypoxia/Reoxygenation Injury. Mol Neurobiol 2023; 60:5366-5377. [PMID: 37316758 DOI: 10.1007/s12035-023-03421-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 06/02/2023] [Indexed: 06/16/2023]
Abstract
There are limited therapeutic options for patient with traumatic spinal cord injury (SCI). Phosphoinositide 3-kinase family (PI3Ks) are the key molecules for regulating cell autophagy, which is a possible way of treating SCI. As we know, PI3K family are composed of eight isoforms, which are distributed into three classes. While the role of PI3Ks in regulating autophagy is controversial and the effects may be in a cell-specific manner. Different isoforms do not distribute in neural cells consistently and it is not clear how the PI3K isoforms regulate and interact with autophagy. Therefore, we explored the distributions and expression of different PI3K isoforms in two key neural cells (PC12 cells and astrocytes). The results showed that the expression of LC3II/I and p62, which are the markers of autophagy, changed in different patterns in PC12 cells and astrocytes after hypoxia/reoxygenation injury (H/R). Furthermore, the mRNA level of eight PI3K isoforms did not change in the same way, and even for the same isoform the mRNA activities are different between PC12 cells and astrocytes. What is more, the results of western blot of PI3K isoforms after H/R were inconsistent with the relevant mRNA. Based on this study, the therapeutic effects of regulating autophagy on SCI are not confirmed definitely, and its molecular mechanisms may be related with different temporal and spatial patterns of activation and distributions of PI3K isoforms.
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Affiliation(s)
- Duo Zhang
- Department of Orthopedics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Xuanyu Chen
- Department of Orthopedics, Capital Medical University Electric Power Hospital, Beijing, 100073, China
| | - Baoge Liu
- Department of Orthopedics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China.
| | - Yuan Yuan
- Department of Spinal Cord Injury Rehabilitation, China Rehabilitation Research Center, Beijing, 100068, China
| | - Wei Cui
- Department of Orthopedics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Di Zhu
- Department of Orthopedics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Jichao Zhu
- Department of Orthopedics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Shuo Duan
- Department of Orthopedics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
| | - Chenxi Li
- Department of Orthopedics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China
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Sternberg AR, Roepe PD. Heterologous Expression, Purification, and Functional Analysis of the Plasmodium falciparum Phosphatidylinositol 4-Kinase IIIβ. Biochemistry 2020; 59:2494-2506. [PMID: 32543181 DOI: 10.1021/acs.biochem.0c00259] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Recently, we heterologously expressed, purified, and analyzed the function of the sole Plasmodium falciparum phosphatidylinositol 3-kinase (PI3K), found that the enzyme is a "class III" or "Vps34" PI3K, and found that it is irreversibly inhibited by Fe2+-mediated covalent, nonspecific interactions with the leading antimalarial drug, dihydroartemisinin [Hassett, M. R., et al. (2017) Biochemistry 56, 4335-4345]. One of several P. falciparum phosphatidylinositol 4-kinases [putative IIIβ isoform (PfPI4KIIIβ)] has generated similar interest as a druggable target; however, no validation of the mechanism of action for putative PfPI4K inhibitors has yet been possible due to the lack of purified PfPI4KIIIβ. We therefore codon optimized the pfpi4kIIIβ gene, successfully expressed the protein in yeast, and purified an N-lobe catalytic domain PfPI4KIIIβ protein. Using an enzyme-linked immunosorbent assay strategy previously perfected for analysis of PfPI3K (PfVps34), we measured the apparent initial rate, Km,app(ATP), and other enzyme characteristics and found full activity for the construct and that PfPI4KIIIβ activity is most consistent with the class IIIβ designation. Because several novel antimalarial drug candidates with different chemical scaffolds have been proposed to target PfPI4KIIIβ, we titrated enzyme inhibition for these candidates versus purified PfPI4KIIIβ and PfVps34. We also analyzed the activity versus purified PfPI4KIIIβ mutants previously expressed in P. falciparum selected for resistance to these drugs. Interestingly, we found that a putative PfPI4KIIIβ inhibitor currently in advanced trials (MMV390048; MMV '0048) is a potent inhibitor of both PfVps34 and PfPI4KIIIβ. These data are helpful for further preclinical optimization of an exciting new class of P. falciparum PI kinase inhibitor ("PfPIKi") antimalarial drugs.
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Affiliation(s)
- Anna R Sternberg
- Department of Chemistry and Department of Biochemistry and Cellular and Molecular Biology, Georgetown University, 37th & O Street Northwest, Washington, D.C. 20057, United States
| | - Paul D Roepe
- Department of Chemistry and Department of Biochemistry and Cellular and Molecular Biology, Georgetown University, 37th & O Street Northwest, Washington, D.C. 20057, United States
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Role of Plasmodium falciparum Kelch 13 Protein Mutations in P. falciparum Populations from Northeastern Myanmar in Mediating Artemisinin Resistance. mBio 2020; 11:mBio.01134-19. [PMID: 32098812 PMCID: PMC7042691 DOI: 10.1128/mbio.01134-19] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Artemisinin resistance has emerged in Southeast Asia, endangering the substantial progress in malaria elimination worldwide. It is associated with mutations in the PfK13 protein, but how PfK13 mediates artemisinin resistance is not completely understood. Here we used a new antibody against PfK13 to show that the PfK13 protein is expressed in all stages of the asexual intraerythrocytic cycle as well as in gametocytes and is partially localized in the endoplasmic reticulum. By introducing four PfK13 mutations into the 3D7 strain and reverting these mutations in field parasite isolates, we determined the impacts of these mutations identified in the parasite populations from northern Myanmar on the ring stage using the in vitro ring survival assay. The introduction of the N458Y mutation into the 3D7 background significantly increased the survival rates of the ring-stage parasites but at the cost of the reduced fitness of the parasites. Introduction of the F446I mutation, the most prevalent PfK13 mutation in northern Myanmar, did not result in a significant increase in ring-stage survival after exposure to dihydroartemisinin (DHA), but these parasites showed extended ring-stage development. Further, parasites with the F446I mutation showed only a marginal loss of fitness, partially explaining its high frequency in northern Myanmar. Conversely, reverting all these mutations, except for the C469Y mutation, back to their respective wild types reduced the ring-stage survival of these isolates in response to in vitro DHA treatment. Mutations in the Plasmodium falciparum Kelch 13 (PfK13) protein are associated with artemisinin resistance. PfK13 is essential for asexual erythrocytic development, but its function is not known. We tagged the PfK13 protein with green fluorescent protein in P. falciparum to study its expression and localization in asexual and sexual stages. We used a new antibody against PfK13 to show that the PfK13 protein is expressed ubiquitously in both asexual erythrocytic stages and gametocytes and is localized in punctate structures, partially overlapping an endoplasmic reticulum marker. We introduced into the 3D7 strain four PfK13 mutations (F446I, N458Y, C469Y, and F495L) identified in parasites from the China-Myanmar border area and characterized the in vitro artemisinin response phenotypes of the mutants. We found that all the parasites with the introduced PfK13 mutations showed higher survival rates in the ring-stage survival assay (RSA) than the wild-type (WT) control, but only parasites with N458Y displayed a significantly higher RSA value (26.3%) than the WT control. After these PfK13 mutations were reverted back to the WT in field parasite isolates, all revertant parasites except those with the C469Y mutation showed significantly lower RSA values than their respective parental isolates. Although the 3D7 parasites with introduced F446I, the predominant PfK13 mutation in northern Myanmar, did not show significantly higher RSA values than the WT, they had prolonged ring-stage development and showed very little fitness cost in in vitro culture competition assays. In comparison, parasites with the N458Y mutations also had a prolonged ring stage and showed upregulated resistance pathways in response to artemisinin, but this mutation produced a significant fitness cost, potentially leading to their lower prevalence in the Greater Mekong subregion.
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Heller LE, Roepe PD. Artemisinin-Based Antimalarial Drug Therapy: Molecular Pharmacology and Evolving Resistance. Trop Med Infect Dis 2019; 4:tropicalmed4020089. [PMID: 31167396 PMCID: PMC6631165 DOI: 10.3390/tropicalmed4020089] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 05/21/2019] [Accepted: 05/24/2019] [Indexed: 12/27/2022] Open
Abstract
The molecular pharmacology of artemisinin (ART)-based antimalarial drugs is incompletely understood. Clinically, these drugs are used in combination with longer lasting partner drugs in several different artemisinin combination therapies (ACTs). ACTs are currently the standard of care against Plasmodium falciparum malaria across much of the world. A harbinger of emerging artemisinin resistance (ARTR), known as the delayed clearance phenotype (DCP), has been well documented in South East Asia (SEA) and is beginning to affect the efficacy of some ACTs. Though several genetic mutations have been associated with ARTR/DCP, a molecular mechanism remains elusive. This paper summarizes our current understanding of ART molecular pharmacology and hypotheses for ARTR/DCP.
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Affiliation(s)
- Laura E Heller
- Departments of Chemistry and of Biochemistry and Cellular and Molecular Biology, Georgetown University, 37th and O Streets NW, Washington, DC 20057, USA.
| | - Paul D Roepe
- Departments of Chemistry and of Biochemistry and Cellular and Molecular Biology, Georgetown University, 37th and O Streets NW, Washington, DC 20057, USA.
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Heller LE, Goggins E, Roepe PD. Dihydroartemisinin-Ferriprotoporphyrin IX Adduct Abundance in Plasmodium falciparum Malarial Parasites and the Relationship to Emerging Artemisinin Resistance. Biochemistry 2018; 57:6935-6945. [PMID: 30512926 DOI: 10.1021/acs.biochem.8b00960] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Previously (Heller, L. E., and Roepe, P. D. Quantification of Free Ferriprotoporphyrin IX Heme and Hemozoin for Artemisinin Sensitive versus Delayed Clearance Phenotype Plasmodium falciparum Malarial Parasites. Biochemistry, DOI: 10.1021/acs.biochem.8b00959, preceding paper in this issue), we quantified free ferriprotoporphyrin IX (FPIX) heme abundance for control versus delayed clearance phenotype (DCP) intraerythrocytic Plasmodium falciparum malarial parasites. Because artemisinin drugs are activated by free FPIX, these data predict that the abundance of long-hypothesized toxic artemisinin drug-FPIX covalent adducts might differ for control versus DCP parasites. If so, this would have important repercussions for understanding the mechanism of the DCP, also known as emerging artemisinin resistance. To test these predictions, we studied in vitro formation of FPIX-dihydroartemisinin (DHA) adducts and then for the first time quantified the abundance of FPIX-DHA adducts formed within live P. falciparum versus the stage of intraerythrocytic development. Using matched isogenic parasite strains, we quantified the adduct for DCP versus control parasite strains and found that mutant PfK13 mediates lower adduct abundance for DCP parasites. The results suggest improved models for the molecular pharmacology of artemisinin-based antimalarial drugs and the molecular mechanism of the DCP.
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Affiliation(s)
- Laura E Heller
- Department of Chemistry and Department of Biochemistry and Cellular and Molecular Biology , Georgetown University , 37th and O Streets Northwest , Washington, D.C. 20057 , United States
| | - Eibhlin Goggins
- Department of Chemistry and Department of Biochemistry and Cellular and Molecular Biology , Georgetown University , 37th and O Streets Northwest , Washington, D.C. 20057 , United States
| | - Paul D Roepe
- Department of Chemistry and Department of Biochemistry and Cellular and Molecular Biology , Georgetown University , 37th and O Streets Northwest , Washington, D.C. 20057 , United States
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Hassett MR, Sternberg AR, Riegel BE, Thomas CJ, Roepe PD. Heterologous Expression, Purification, and Functional Analysis of Plasmodium falciparum Phosphatidylinositol 3′-Kinase. Biochemistry 2017; 56:4335-4345. [DOI: 10.1021/acs.biochem.7b00416] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Matthew R. Hassett
- Department of Chemistry and Department of Biochemistry & Cellular & Molecular Biology, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
| | - Anna R. Sternberg
- Department of Chemistry and Department of Biochemistry & Cellular & Molecular Biology, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
| | - Bryce E. Riegel
- Department of Chemistry and Department of Biochemistry & Cellular & Molecular Biology, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
| | - Craig J. Thomas
- Division
of Preclinical Innovation, National Center for Advancing Translational
Sciences, National Institutes of Health, Rockville, Maryland 20892, United States
| | - Paul D. Roepe
- Department of Chemistry and Department of Biochemistry & Cellular & Molecular Biology, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, United States
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