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Kur IM, Weigert A. Phosphatidylserine externalization as immune checkpoint in cancer. Pflugers Arch 2024:10.1007/s00424-024-02948-7. [PMID: 38573347 DOI: 10.1007/s00424-024-02948-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/13/2024] [Accepted: 03/16/2024] [Indexed: 04/05/2024]
Abstract
Cancer is the second leading cause of mortality worldwide. Despite recent advances in cancer treatment including immunotherapy with immune checkpoint inhibitors, new unconventional biomarkers and targets for the detection, prognosis, and treatment of cancer are still in high demand. Tumor cells are characterized by mutations that allow their unlimited growth, program their local microenvironment to support tumor growth, and spread towards distant sites. While a major focus has been on altered tumor genomes and proteomes, crucial signaling molecules such as lipids have been underappreciated. One of these molecules is the membrane phospholipid phosphatidylserine (PS) that is usually found at cytosolic surfaces of cellular membranes but can be rapidly and massively shuttled to the extracellular leaflet of the plasma membrane during apoptosis to serve as a limiting factor for immune responses. These immunosuppressive interactions are exploited by tumor cells to evade the immune system. In this review, we describe mechanisms of immune regulation in tumors, discuss if PS may constitute an inhibitory immune checkpoint, and describe current and future strategies for targeting PS to reactivate the tumor-associated immune system.
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Affiliation(s)
- Ivan-Maximiliano Kur
- Faculty of Medicine, Institute of Biochemistry I, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Andreas Weigert
- Faculty of Medicine, Institute of Biochemistry I, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
- Frankfurt Cancer Institute, Goethe-University Frankfurt, 60596, Frankfurt, Germany.
- German Cancer Consortium (DKTK), Partner Site, Frankfurt, Germany.
- Cardiopulmonary Institute (CPI), 60590, Frankfurt, Germany.
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2
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Shao N, Qiu H, Liu J, Xiao D, Zhao J, Chen C, Wan J, Guo M, Liang G, Zhao X, Xu L. Targeting lipid metabolism of macrophages: A new strategy for tumor therapy. J Adv Res 2024:S2090-1232(24)00071-7. [PMID: 38373649 DOI: 10.1016/j.jare.2024.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/16/2024] [Accepted: 02/15/2024] [Indexed: 02/21/2024] Open
Abstract
BACKGROUND Lipid metabolism has been implicated in a variety of normal cellular processes and strongly related to the development of multiple diseases, including tumor. Tumor-associated macrophage (TAM) has emerged as a crucial regulator in tumorigenesis and promising target for tumor treatment. AIM OF REVIEW A thorough understanding of TAM lipid metabolism and its value in tumorigenesis may provide new ideas for TAM-based anti-tumor therapy. Key scientific concepts of review: TAMs can be divided into two main types, M1-like TAMs and M2-like TAMs, which play anti-tumor and pro-tumor functions in tumor occurrence and development, respectively. Accumulating evidence has shown that lipid metabolic reprogramming, including fatty acid uptake and utilization, cholesterol expulsion, controls the polarization of TAMs and affects the tumorgenesis. These advances in uncovering the intricacies of lipid metabolism and TAMs have yielded new insights on tumor development and treatment. In this review, we aim to provide an update on the current understanding of the lipid metabolic reprogramming made by TAMs to adapt to the harsh tumor microenvironment (TME). In particular, we emphasize that there is complex lipid metabolism connections between TAMs and distinct tumors, which influences TAM to bias from M1 to M2 phenotype in tumor progression, and ultimately promotes tumor occurrence and development. Finally, we discuss the existing issues on therapeutic strategies by reprogramming TAMs based on lipid metabolism regulation (or increasing the ratio of M1/M2-like TAMs) that could be applied in the future to clinical tumor treatment.
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Affiliation(s)
- Nan Shao
- Special Key Laboratory of Gene Detection & Therapy of Guizhou Province, Zunyi Medical University, Zunyi, Guizhou 563000, China; Department of Immunology, Zunyi Medical University, Zunyi, Guizhou 563000, China
| | - Hui Qiu
- Special Key Laboratory of Gene Detection & Therapy of Guizhou Province, Zunyi Medical University, Zunyi, Guizhou 563000, China; Department of Immunology, Zunyi Medical University, Zunyi, Guizhou 563000, China
| | - Jing Liu
- Special Key Laboratory of Gene Detection & Therapy of Guizhou Province, Zunyi Medical University, Zunyi, Guizhou 563000, China; Department of Immunology, Zunyi Medical University, Zunyi, Guizhou 563000, China
| | - Daimin Xiao
- Special Key Laboratory of Gene Detection & Therapy of Guizhou Province, Zunyi Medical University, Zunyi, Guizhou 563000, China
| | - Juanjuan Zhao
- Special Key Laboratory of Gene Detection & Therapy of Guizhou Province, Zunyi Medical University, Zunyi, Guizhou 563000, China; Department of Immunology, Zunyi Medical University, Zunyi, Guizhou 563000, China
| | - Chao Chen
- Special Key Laboratory of Gene Detection & Therapy of Guizhou Province, Zunyi Medical University, Zunyi, Guizhou 563000, China; Department of Immunology, Zunyi Medical University, Zunyi, Guizhou 563000, China
| | - Jiajia Wan
- Special Key Laboratory of Gene Detection & Therapy of Guizhou Province, Zunyi Medical University, Zunyi, Guizhou 563000, China; Department of Immunology, Zunyi Medical University, Zunyi, Guizhou 563000, China
| | - Mengmeng Guo
- Special Key Laboratory of Gene Detection & Therapy of Guizhou Province, Zunyi Medical University, Zunyi, Guizhou 563000, China; Department of Immunology, Zunyi Medical University, Zunyi, Guizhou 563000, China
| | - Guiyou Liang
- Department of Cardiovascular Surgery, Affiliated Hospital of Guizhou Medical University, Guiyang 550031, China.
| | - Xu Zhao
- School of Medicine, Guizhou University, Guizhou, Guiyang 550025, China; Special Key Laboratory of Gene Detection & Therapy of Guizhou Province, Zunyi Medical University, Zunyi, Guizhou 563000, China.
| | - Lin Xu
- Special Key Laboratory of Gene Detection & Therapy of Guizhou Province, Zunyi Medical University, Zunyi, Guizhou 563000, China; Department of Immunology, Zunyi Medical University, Zunyi, Guizhou 563000, China; Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, Guizhou 563000, China.
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Nakatsu F, Kawasaki A. Phosphatidylserine turns the gears of phospholipids in B cell lymphoma. J Cell Biol 2024; 223:e202401047. [PMID: 38270920 PMCID: PMC10818062 DOI: 10.1083/jcb.202401047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024] Open
Abstract
Phosphatidylserine levels and distribution are tightly controlled by dedicated enzymes at the ER and plasma membrane. Nakatsu and Kawasaki discuss new work by Aoki and colleagues (https://doi.org/10.1083/jcb.202212074), which reveals an acute reliance on phosphatidylserine synthesis in B cell lymphomas needed to prevent aberrant B cell receptor activation and ensuing apoptosis.
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Affiliation(s)
- Fubito Nakatsu
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
| | - Asami Kawasaki
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
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Omi J, Kato T, Yoshihama Y, Sawada K, Kono N, Aoki J. Phosphatidylserine synthesis controls oncogenic B cell receptor signaling in B cell lymphoma. J Cell Biol 2024; 223:e202212074. [PMID: 38048228 PMCID: PMC10694799 DOI: 10.1083/jcb.202212074] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 09/13/2023] [Accepted: 11/09/2023] [Indexed: 12/06/2023] Open
Abstract
Cancer cells harness lipid metabolism to promote their own survival. We screened 47 cancer cell lines for survival dependency on phosphatidylserine (PS) synthesis using a PS synthase 1 (PTDSS1) inhibitor and found that B cell lymphoma is highly dependent on PS. Inhibition of PTDSS1 in B cell lymphoma cells caused a reduction of PS and phosphatidylethanolamine levels and an increase of phosphoinositide levels. The resulting imbalance of the membrane phospholipidome lowered the activation threshold for B cell receptor (BCR), a B cell-specific survival mechanism. BCR hyperactivation led to aberrant elevation of downstream Ca2+ signaling and subsequent apoptotic cell death. In a mouse xenograft model, PTDSS1 inhibition efficiently suppressed tumor growth and prolonged survival. Our findings suggest that PS synthesis may be a critical vulnerability of malignant B cell lymphomas that can be targeted pharmacologically.
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Affiliation(s)
- Jumpei Omi
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | | | | | - Koki Sawada
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Nozomu Kono
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Junken Aoki
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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Has C, Das SL. The Functionality of Membrane-Inserting Proteins and Peptides: Curvature Sensing, Generation, and Pore Formation. J Membr Biol 2023; 256:343-372. [PMID: 37650909 DOI: 10.1007/s00232-023-00289-7] [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: 01/17/2023] [Accepted: 08/04/2023] [Indexed: 09/01/2023]
Abstract
Proteins and peptides with hydrophobic and amphiphilic segments are responsible for many biological functions. The sensing and generation of membrane curvature are the functions of several protein domains or motifs. While some specific membrane proteins play an essential role in controlling the curvature of distinct intracellular membranes, others participate in various cellular processes such as clathrin-mediated endocytosis, where several proteins sort themselves at the neck of the membrane bud. A few membrane-inserting proteins form nanopores that permeate selective ions and water to cross the membrane. In addition, many natural and synthetic small peptides and protein toxins disrupt the membrane by inducing nonspecific pores in the membrane. The pore formation causes cell death through the uncontrolled exchange between interior and exterior cellular contents. In this article, we discuss the insertion depth and orientation of protein/peptide helices, and their role as a sensor and inducer of membrane curvature as well as a pore former in the membrane. We anticipate that this extensive review will assist biophysicists to gain insight into curvature sensing, generation, and pore formation by membrane insertion.
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Affiliation(s)
- Chandra Has
- Department of Chemical Engineering, GSFC University, Vadodara, 391750, Gujarat, India.
| | - Sovan Lal Das
- Physical and Chemical Biology Laboratory and Department of Mechanical Engineering, Indian Institute of Technology, Palakkad, 678623, Kerala, India
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Lei Y, Zhou B, Meng X, Liang M, Song W, Liang Y, Gao Y, Wang M. A risk score model based on lipid metabolism-related genes could predict response to immunotherapy and prognosis of lung adenocarcinoma: a multi-dataset study and cytological validation. Discov Oncol 2023; 14:188. [PMID: 37874388 PMCID: PMC10597940 DOI: 10.1007/s12672-023-00802-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 10/08/2023] [Indexed: 10/25/2023] Open
Abstract
BACKGROUND Lipid metabolism is a key factor in tumorigenesis and drug resistance, and models related to lipid metabolism have shown potential to predict survival and curative effects of adjuvant therapy in various cancers. However, the relationship between lipid metabolism and prognosis and treatment response of lung adenocarcinoma (LUAD) are still unclear. METHODS We enrolled seven bulk RNA-sequence datasets (GSE37745, GSE19188, GSE30219, GSE31547, GSE41271, GSE42127, and GSE72094) from the GEO database and one single-cell RNA-sequencing dataset (GSE117570) from the TISCH2 database. Non-negative matrix factorization (NMF) was utilized to construct the risk score model based on lipid score calculated by GSVA algorithm. Phs000452.v3, PMID: 26359337, PMID: 32472114, PRJEB23709 datasets were used to test the response to immunotherapy. Drug sensitivity analysis was assessed according to the GDSC database, and immunotherapy response was evaluated using the Wilcoxon test. Cellular function assays including clone formation, EDU assays and flow cytometry were implemented to explore the phenotype alteration caused by the knockdown of PTDSS1, which is one of key gene in risk score model. RESULTS We analyzed both bulk and single-cell RNA sequencing data to establish and validate a risk score model based on 18 lipid metabolism-related genes with significant impact on prognosis. After divided the patients into two groups according to risk score, we identified differences in lipid-related metabolic processes and a detailed portrait of the immune landscapes of high- and low-risk groups. Moreover, we investigated the potentials of our risk score in predicting response to immunotherapy and drug sensitivity. In addition, we silenced PTDSS1 in LUAD cell lines, and found that the proliferation of the cells was weakened, and the apoptosis of the cells was increased. CONCLUSION Our study highlights the crucial roles of lipid metabolism in LUAD and provides a reliable risk score model, which can aid in predicting prognosis and response to immunotherapy. Furthermore, we investigated the roles of PTDSS1 in LUAD carcinogenesis, which showed that PTDSS1 regulated proliferation and apoptosis of LUAD cells.
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Affiliation(s)
- Yangyang Lei
- Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Boxuan Zhou
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiangzhi Meng
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Mei Liang
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Weijian Song
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yicheng Liang
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
- Department of Thoracic Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yanjiang West Road, Guangzhou, 510120, China.
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.
| | - Yushun Gao
- Department of Thoracic Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
| | - Minghui Wang
- Department of Thoracic Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yanjiang West Road, Guangzhou, 510120, China.
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.
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7
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Demir Karaman E, Işık Z. Multi-Omics Data Analysis Identifies Prognostic Biomarkers across Cancers. Med Sci (Basel) 2023; 11:44. [PMID: 37489460 PMCID: PMC10366886 DOI: 10.3390/medsci11030044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/18/2023] [Accepted: 06/20/2023] [Indexed: 07/26/2023] Open
Abstract
Combining omics data from different layers using integrative methods provides a better understanding of the biology of a complex disease such as cancer. The discovery of biomarkers related to cancer development or prognosis helps to find more effective treatment options. This study integrates multi-omics data of different cancer types with a network-based approach to explore common gene modules among different tumors by running community detection methods on the integrated network. The common modules were evaluated by several biological metrics adapted to cancer. Then, a new prognostic scoring method was developed by weighting mRNA expression, methylation, and mutation status of genes. The survival analysis pointed out statistically significant results for GNG11, CBX2, CDKN3, ARHGEF10, CLN8, SEC61G and PTDSS1 genes. The literature search reveals that the identified biomarkers are associated with the same or different types of cancers. Our method does not only identify known cancer-specific biomarker genes, but also proposes new potential biomarkers. Thus, this study provides a rationale for identifying new gene targets and expanding treatment options across cancer types.
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Affiliation(s)
- Ezgi Demir Karaman
- Department of Computer Engineering, Institute of Natural and Applied Sciences, Dokuz Eylul University, Izmir 35390, Turkey
| | - Zerrin Işık
- Department of Computer Engineering, Faculty of Engineering, Dokuz Eylul University, Izmir 35390, Turkey
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Korbecki J, Bosiacki M, Gutowska I, Chlubek D, Baranowska-Bosiacka I. Biosynthesis and Significance of Fatty Acids, Glycerophospholipids, and Triacylglycerol in the Processes of Glioblastoma Tumorigenesis. Cancers (Basel) 2023; 15:cancers15072183. [PMID: 37046844 PMCID: PMC10093493 DOI: 10.3390/cancers15072183] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/01/2023] [Accepted: 04/03/2023] [Indexed: 04/08/2023] Open
Abstract
One area of glioblastoma research is the metabolism of tumor cells and detecting differences between tumor and healthy brain tissue metabolism. Here, we review differences in fatty acid metabolism, with a particular focus on the biosynthesis of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) by fatty acid synthase (FASN), elongases, and desaturases. We also describe the significance of individual fatty acids in glioblastoma tumorigenesis, as well as the importance of glycerophospholipid and triacylglycerol synthesis in this process. Specifically, we show the significance and function of various isoforms of glycerol-3-phosphate acyltransferases (GPAT), 1-acylglycerol-3-phosphate O-acyltransferases (AGPAT), lipins, as well as enzymes involved in the synthesis of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI), and cardiolipin (CL). This review also highlights the involvement of diacylglycerol O-acyltransferase (DGAT) in triacylglycerol biosynthesis. Due to significant gaps in knowledge, the GEPIA database was utilized to demonstrate the significance of individual enzymes in glioblastoma tumorigenesis. Finally, we also describe the significance of lipid droplets in glioblastoma and the impact of fatty acid synthesis, particularly docosahexaenoic acid (DHA), on cell membrane fluidity and signal transduction from the epidermal growth factor receptor (EGFR).
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Affiliation(s)
- Jan Korbecki
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
- Department of Anatomy and Histology, Collegium Medicum, University of Zielona Góra, Zyty 28 Str., 65-046 Zielona Góra, Poland
| | - Mateusz Bosiacki
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
- Department of Functional Diagnostics and Physical Medicine, Faculty of Health Sciences, Pomeranian Medical University in Szczecin, Żołnierska 54 Str., 71-210 Szczecin, Poland
| | - Izabela Gutowska
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
| | - Dariusz Chlubek
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
| | - Irena Baranowska-Bosiacka
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University in Szczecin, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
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Yang A, Wu Q, Wang A, Chen Q, Yang J, Tao Y, Sun Y, Zhang J. Integrated transcriptomics and metabolomics analyses to investigate the anticancer mechanisms of cinobufagin against liver cancer through interfering with lipid, amino acid, carbohydrate, and nucleotide metabolism. Bioorg Chem 2022; 130:106229. [DOI: 10.1016/j.bioorg.2022.106229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 10/10/2022] [Accepted: 10/23/2022] [Indexed: 11/02/2022]
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Akalu YT, Mercau ME, Ansems M, Hughes LD, Nevin J, Alberto EJ, Liu XN, He LZ, Alvarado D, Keler T, Kong Y, Philbrick WM, Bosenberg M, Finnemann SC, Iavarone A, Lasorella A, Rothlin CV, Ghosh S. Tissue-specific modifier alleles determine Mertk loss-of-function traits. eLife 2022; 11:80530. [PMID: 35969037 PMCID: PMC9433089 DOI: 10.7554/elife.80530] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/13/2022] [Indexed: 11/19/2022] Open
Abstract
Knockout (KO) mouse models play critical roles in elucidating biological processes behind disease-associated or disease-resistant traits. As a presumed consequence of gene KO, mice display certain phenotypes. Based on insight into the molecular role of said gene in a biological process, it is inferred that the particular biological process causally underlies the trait. This approach has been crucial towards understanding the basis of pathological and/or advantageous traits associated with Mertk KO mice. Mertk KO mice suffer from severe, early-onset retinal degeneration. MERTK, expressed in retinal pigment epithelia, is a receptor tyrosine kinase with a critical role in phagocytosis of apoptotic cells or cellular debris. Therefore, early-onset, severe retinal degeneration was described to be a direct consequence of failed MERTK-mediated phagocytosis of photoreceptor outer segments by retinal pigment epithelia. Here, we report that the loss of Mertk alone is not sufficient for retinal degeneration. The widely used Mertk KO mouse carries multiple coincidental changes in its genome that affect the expression of a number of genes, including the Mertk paralog Tyro3. Retinal degeneration manifests only when the function of Tyro3 is concomitantly lost. Furthermore, Mertk KO mice display improved anti-tumor immunity. MERTK is expressed in macrophages. Therefore, enhanced anti-tumor immunity was inferred to result from the failure of macrophages to dispose of cancer cell corpses, resulting in a pro-inflammatory tumor microenvironment. The resistance against two syngeneic mouse tumor models observed in Mertk KO mice is not, however, phenocopied by the loss of Mertk alone. Neither Tyro3 nor macrophage phagocytosis by alternate genetic redundancy accounts for the absence of anti-tumor immunity. Collectively, our results indicate that context-dependent epistasis of independent modifier alleles determines Mertk KO traits.
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Affiliation(s)
- Yemsratch T Akalu
- Department of Immunobiology, Yale School of MedicineNew HavenUnited States
| | - Maria E Mercau
- Department of Immunobiology, Yale School of MedicineNew HavenUnited States
| | - Marleen Ansems
- Department of Immunobiology, Yale School of MedicineNew HavenUnited States
| | - Lindsey D Hughes
- Department of Immunobiology, Yale School of MedicineNew HavenUnited States
| | - James Nevin
- Department of Immunobiology, Yale School of MedicineNew HavenUnited States
| | - Emily J Alberto
- Department of Immunobiology, Yale School of MedicineNew HavenUnited States
| | - Xinran N Liu
- Department of Cell Biology, Center for Cellular and Molecular Imaging, Yale School of MedicineNew HavenUnited States
| | - Li-Zhen He
- Celldex TherapeuticsNew HavenUnited States
| | | | | | - Yong Kong
- Department of Molecular Biophysics and Biochemistry, W. M. Keck Foundation Biotechnology Resource Laboratory, School of Medicine, Yale UniversityNew HavenUnited States
| | - William M Philbrick
- Center on Endocrinology and Metabolism, Yale Genome Editing Center, School of Medicine, Yale UniversityNew HavenUnited States
| | - Marcus Bosenberg
- Departments of Dermatology, Pathology and Immunobiology, Yale School of MedicineNew HavenUnited States
| | - Silvia C Finnemann
- Center for Cancer, Genetic Diseases and Gene Regulation, Department of Biological Sciences, Fordham UniversityBronxUnited States
| | - Antonio Iavarone
- Departments of Neurology and Pathology and Cell Biology, Institute for Cancer Genetics, Columbia Medical CenterNew YorkUnited States
| | - Anna Lasorella
- Departments of Pediatrics and Pathology and Cell Biology, Institute for Cancer Genetics, Columbia UniversityNew YorkUnited States
| | - Carla V Rothlin
- Departments of Immunobiology and Pharmacology, Yale School of MedicineNew HavenUnited States
| | - Sourav Ghosh
- Departments of Neurology and Pharmacology, Yale School of MedicineNew HavenUnited States
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Wood PL, Woltjer RL. Serine ether glycerophospholipids: Decrements in the frontal cortex associated with mild cognitive impairment and Alzheimer's disease. Front Aging Neurosci 2022; 14:981868. [PMID: 36004004 PMCID: PMC9393623 DOI: 10.3389/fnagi.2022.981868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 07/14/2022] [Indexed: 12/15/2022] Open
Abstract
Ether glycerophospholipids (GPL) are involved in membrane fluidity and fusion. Vinyl-ether GPL are also conjectured to provide antioxidant capacity in the brain. The roles of these lipids in the processes involved in the development of dementia are not understood but choline and ethanolamine vinyl-ether GPL (i.e., plasmalogens) are decreased in the brains of subjects with dementia. In contrast, serine ether and vinyl-ether GPL have not been investigated in human brain. We therefore undertook an evaluation of these lipids, utilizing high-resolution mass spectrometry (HR-MS), in tissues from control and dementia subjects that we had previously characterized in-depth. We can report for the first time that a number of serine ether GPL and a more limited number of serine plasmalogens are present in human frontal cortex. In addition, we found that some of these frontal cortex lipids are decreased in Mild Cognitive Impairment (MCI), early-onset Alzheimer's disease (EOAD), and late-onset AD (LOAD). In contrast no alterations in serine ether GPL were monitored in the frontal cortex of donors with schizophrenia, demonstrating disease specificity. These data suggest that further studies of the roles of ether GPL, including serine ether GPL, in brain function are worthy of undertaking.
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Affiliation(s)
- Paul L. Wood
- Metabolomics Unit, College of Veterinary Medicine, Lincoln Memorial University, Harrogate, TN, United States,*Correspondence: Paul L. Wood,
| | - Randall L. Woltjer
- Department of Pathology, Oregon Health and Science University, Portland, OR, United States
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