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Silvaroli JA, Bisunke B, Kim JY, Stayton A, Jayne LA, Martinez SA, Nguyen C, Patel PS, Vanichapol T, Verma V, Akhter J, Bolisetty S, Madhavan SM, Kuscu C, Coss CC, Zepeda-Orozco D, Parikh SV, Satoskar AA, Davidson AJ, Eason JD, Szeto HH, Pabla NS, Bajwa A. Genome-Wide CRISPR Screen Identifies Phospholipid Scramblase 3 as the Biological Target of Mitoprotective Drug SS-31. J Am Soc Nephrol 2024; 35:681-695. [PMID: 38530359 PMCID: PMC11164119 DOI: 10.1681/asn.0000000000000338] [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: 07/06/2023] [Accepted: 03/12/2024] [Indexed: 03/27/2024] Open
Abstract
Key Points Szeto–Schiller-31–mediated mitoprotection is phospholipid scramblase 3–dependent. Phospholipid scramblase 3 is required for recovery after AKI. Background The synthetic tetrapeptide Szeto–Schiller (SS)-31 shows promise in alleviating mitochondrial dysfunction associated with common diseases. However, the precise pharmacological basis of its mitoprotective effects remains unknown. Methods To uncover the biological targets of SS-31, we performed a genome-scale clustered regularly interspaced short palindromic repeats screen in human kidney-2, a cell culture model where SS-31 mitigates cisplatin-associated cell death and mitochondrial dysfunction. The identified hit candidate gene was functionally validated using knockout cell lines, small interfering RNA-mediated downregulation, and tubular epithelial–specific conditional knockout mice. Biochemical interaction studies were also performed to examine the interaction of SS-31 with the identified target protein. Results Our primary screen and validation studies in hexokinase 2 and primary murine tubular epithelial cells showed that phospholipid scramblase 3 (PLSCR3), an understudied inner mitochondrial membrane protein, was essential for the protective effects of SS-31. For in vivo validation, we generated tubular epithelial–specific knockout mice and found that Plscr3 gene ablation did not influence kidney function under normal conditions or affect the severity of cisplatin and rhabdomyolysis-associated AKI. However, Plscr3 gene deletion completely abrogated the protective effects of SS-31 during cisplatin and rhabdomyolysis-associated AKI. Biochemical studies showed that SS-31 directly binds to a previously uncharacterized N -terminal domain and stimulates PLSCR3 scramblase activity. Finally, PLSCR3 protein expression was found to be increased in the kidneys of patients with AKI. Conclusions PLSCR3 was identified as the essential biological target that facilitated the mitoprotective effects of SS-31 in vitro and in vivo .
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Affiliation(s)
- Josie A. Silvaroli
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Bijay Bisunke
- Department of Genetics, Genomics, and Informatics; College of Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Ji Young Kim
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Amanda Stayton
- Department of Genetics, Genomics, and Informatics; College of Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Laura A. Jayne
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Shirely A. Martinez
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Christopher Nguyen
- Department of Genetics, Genomics, and Informatics; College of Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Prisha S. Patel
- Department of Genetics, Genomics, and Informatics; College of Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Thitinee Vanichapol
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - Vivek Verma
- Department of Medicine, University of Alabama, Birmingham, Alabama
| | - Juheb Akhter
- Department of Medicine, University of Alabama, Birmingham, Alabama
| | | | - Sethu M. Madhavan
- Division of Nephrology, Department of Medicine, The Ohio State University, Columbus, Ohio
| | - Cem Kuscu
- Department of Surgery, College of Medicine, Transplant Research Institute, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Christopher C. Coss
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Diana Zepeda-Orozco
- Department of Pediatrics, The Ohio State University College of Medicine and Kidney and Urinary Tract Research Center, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio
| | - Samir V. Parikh
- Division of Nephrology, Department of Medicine, The Ohio State University, Columbus, Ohio
| | - Anjali A. Satoskar
- Division of Renal and Transplant Pathology, Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Alan J. Davidson
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
| | - James D. Eason
- Department of Surgery, College of Medicine, Transplant Research Institute, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Hazel H. Szeto
- Social Profit Network Research Lab, Menlo Park, California
| | - Navjot S. Pabla
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Amandeep Bajwa
- Department of Genetics, Genomics, and Informatics; College of Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee
- Department of Surgery, College of Medicine, Transplant Research Institute, The University of Tennessee Health Science Center, Memphis, Tennessee
- Department of Microbiology, Immunology, and Biochemistry; College of Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee
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2
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Zhu L, Jiao H, Gao W, Gong P, Shi C, Zhang F, Zhao J, Lu X, Liu B, Luo J. MiR-103-5p deficiency suppresses lipid accumulation via upregulating PLSCR4 and its host gene PANK3 in goat mammary epithelial cells. Int J Biol Macromol 2024; 267:131240. [PMID: 38583827 DOI: 10.1016/j.ijbiomac.2024.131240] [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: 01/07/2024] [Revised: 03/09/2024] [Accepted: 03/27/2024] [Indexed: 04/09/2024]
Abstract
Lipids are intimately related to the unique flavor and nutritional values of goat milk. MicroRNAs (miRNA) participate in the regulation of various biological functions, including the synthesis and degradation of lipids. Several studies have shown that miR-103 is involved in the regulation of lipid metabolism, however, the molecular mechanism by which miR-103 regulates lipid metabolism in goat mammary gland is poorly understood. In this study, miR-103 was knocked out in goat mammary epithelial cells (GMECs) by CRISPR/Cas9, and the accumulation of lipid droplets, triglycerides, and cholesterol in the cells was suppressed subsequently. Overexpression or knockdown of miR-103-5p and miR-103-3p in GMECs revealed that it was miR-103-5p that promoted lipid accumulation but not miR-103-3p. In addition, Pantothenate Kinase 3 (PANK3), the host gene of miR-103, and Phospholipid Scramblase 4 (PLSCR4) were identified as the target genes of miR-103-5p by dual fluorescein and miRNA pulldown. Furthermore, we identified that cellular lipid levels were negatively regulated by PANK3 and PLSCR4. Lastly, in miR-103 knockout GMECs, the knockdown of PANK and PLSCR4 rescued the lipid accumulation. These findings suggest that miR-103-5p promotes lipid accumulation by targeting PLSCR4 and the host gene PANK3 in GMECs, providing new insights for the regulation of goat milk lipids via miRNAs.
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Affiliation(s)
- Lu Zhu
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Hongyun Jiao
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Wenchang Gao
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Ping Gong
- Institute of Animal Husbandry Quality Standards, Xinjiang Academy of Animal Sciences, China
| | - Chenbo Shi
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Fuhong Zhang
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Jianqing Zhao
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Xuefeng Lu
- Institute of Animal Husbandry Quality Standards, Xinjiang Academy of Animal Sciences, China
| | - Baolong Liu
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Jun Luo
- Shaanxi Key Laboratory of Molecular Biology for Agriculture, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
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3
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Khan S, Patel MP, Patni AD, Cha SJ. Targeting Plasmodium Life Cycle with Novel Parasite Ligands as Vaccine Antigens. Vaccines (Basel) 2024; 12:484. [PMID: 38793735 PMCID: PMC11125637 DOI: 10.3390/vaccines12050484] [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: 03/28/2024] [Revised: 04/28/2024] [Accepted: 04/30/2024] [Indexed: 05/26/2024] Open
Abstract
The WHO reported an estimated 249 million malaria cases and 608,000 malaria deaths in 85 countries in 2022. A total of 94% of malaria deaths occurred in Africa, 80% of which were children under 5. In other words, one child dies every minute from malaria. The RTS,S/AS01 malaria vaccine, which uses the Plasmodium falciparum circumsporozoite protein (CSP) to target sporozoite infection of the liver, achieved modest efficacy. The Malaria Vaccine Implementation Program (MVIP), coordinated by the WHO and completed at the end of 2023, found that immunization reduced mortality by only 13%. To further reduce malaria death, the development of a more effective malaria vaccine is a high priority. Three malaria vaccine targets being considered are the sporozoite liver infection (pre-erythrocytic stage), the merozoite red blood cell infection (asexual erythrocytic stage), and the gamete/zygote mosquito infection (sexual/transmission stage). These targets involve specific ligand-receptor interactions. However, most current malaria vaccine candidates that target two major parasite population bottlenecks, liver infection, and mosquito midgut infection, do not focus on such parasite ligands. Here, we evaluate the potential of newly identified parasite ligands with a phage peptide-display technique as novel malaria vaccine antigens.
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Affiliation(s)
| | | | | | - Sung-Jae Cha
- Department of Medical Sciences, Mercer University School of Medicine, 1501 Mercer University Drive, Macon, GA 31207, USA; (S.K.); (M.P.P.); (A.D.P.)
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4
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Mavuduru VA, Vadupu L, Ghosh KK, Chakrabortty S, Gulyás B, Padmanabhan P, Ball WB. Mitochondrial phospholipid transport: Role of contact sites and lipid transport proteins. Prog Lipid Res 2024; 94:101268. [PMID: 38195013 DOI: 10.1016/j.plipres.2024.101268] [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: 08/11/2023] [Revised: 01/03/2024] [Accepted: 01/05/2024] [Indexed: 01/11/2024]
Abstract
One of the major constituents of mitochondrial membranes is the phospholipids, which play a key role in maintaining the structure and the functions of the mitochondria. However, mitochondria do not synthesize most of the phospholipids in situ, necessitating the presence of phospholipid import pathways. Even for the phospholipids, which are synthesized within the inner mitochondrial membrane (IMM), the phospholipid precursors must be imported from outside the mitochondria. Therefore, the mitochondria heavily rely on the phospholipid transport pathways for its proper functioning. Since, mitochondria are not part of a vesicular trafficking network, the molecular mechanisms of how mitochondria receive its phospholipids remain a relevant question. One of the major ways that hydrophobic phospholipids can cross the aqueous barrier of inter or intraorganellar spaces is by apposing membranes, thereby decreasing the distance of transport, or by being sequestered by lipid transport proteins (LTPs). Therefore, with the discovery of LTPs and membrane contact sites (MCSs), we are beginning to understand the molecular mechanisms of phospholipid transport pathways in the mitochondria. In this review, we will present a brief overview of the recent findings on the molecular architecture and the importance of the MCSs, both the intraorganellar and interorganellar contact sites, in facilitating the mitochondrial phospholipid transport. In addition, we will also discuss the role of LTPs for trafficking phospholipids through the intermembrane space (IMS) of the mitochondria. Mechanistic insights into different phospholipid transport pathways of mitochondria could be exploited to vary the composition of membrane phospholipids and gain a better understanding of their precise role in membrane homeostasis and mitochondrial bioenergetics.
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Affiliation(s)
- Vijay Aditya Mavuduru
- Department of Biological Sciences, School of Engineering and Sciences, SRM University AP Andhra Pradesh, Guntur, Andhra Pradesh 522240, India
| | - Lavanya Vadupu
- Department of Biological Sciences, School of Engineering and Sciences, SRM University AP Andhra Pradesh, Guntur, Andhra Pradesh 522240, India
| | - Krishna Kanta Ghosh
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore
| | - Sabyasachi Chakrabortty
- Department of Chemistry, School of Engineering and Sciences, SRM University AP Andhra Pradesh, Guntur, Andhra Pradesh 522502, India
| | - Balázs Gulyás
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore; Cognitive Neuroimaging Centre, Nanyang Technological University, Singapore, 59 Nanyang Drive, 636921, Singapore; Department of Clinical Neuroscience, Karolinska Institute, Stockholm 17176, Sweden
| | - Parasuraman Padmanabhan
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, 59 Nanyang Drive, Singapore, 636921, Singapore; Cognitive Neuroimaging Centre, Nanyang Technological University, Singapore, 59 Nanyang Drive, 636921, Singapore.
| | - Writoban Basu Ball
- Department of Biological Sciences, School of Engineering and Sciences, SRM University AP Andhra Pradesh, Guntur, Andhra Pradesh 522240, India.
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5
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Han AX, Long BY, Li CY, Huang DD, Xiong EQ, Li FJ, Wu GL, Liu Q, Yang GB, Hu HY. Machine learning framework develops neutrophil extracellular traps model for clinical outcome and immunotherapy response in lung adenocarcinoma. Apoptosis 2024:10.1007/s10495-024-01947-4. [PMID: 38519636 DOI: 10.1007/s10495-024-01947-4] [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] [Accepted: 02/15/2024] [Indexed: 03/25/2024]
Abstract
Neutrophil extracellular traps (NETs) are novel inflammatory cell death in neutrophils. Emerging studies demonstrated NETs contributed to cancer progression and metastases in multiple ways. This study intends to provide a prognostic NETs signature and therapeutic target for lung adenocarcinoma (LUAD) patients. Consensus cluster analysis performed by 38 reported NET-related genes in TCGA-LUAD cohorts. Then, WGCNA network was conducted to investigate characteristics genes in clusters. Seven machine learning algorithms were assessed for training of the model, the optimal model was picked by C-index and 1-, 3-, 5-year ROC value. Then, we constructed a NETs signature to predict the overall survival of LUAD patients. Moreover, multi-omics validation was performed based on NETs signature. Finally, we constructed stable knockdown critical gene LUAD cell lines to verify biological functions of Phospholipid Scramblase 1 (PLSCR1) in vitro and in vivo. Two NETs-related clusters were identified in LUAD patients. Among them, C2 cluster was provided as "hot" tumor phenotype and exhibited a better prognosis. Then, WGCNA network identified 643 characteristic genes in C2 cluster. Then, Coxboost algorithm proved its optimal performance and provided a prognostic NETs signature. Multi-omics revealed that NETs signature was involved in an immunosuppressive microenvironment and predicted immunotherapy efficacy. In vitro and in vivo experiments demonstrated that knockdown of PLSCR1 inhibited tumor growth and EMT ability. Besides, cocultural assay indicated that the knockdown of PLSCR1 impaired the ability of neutrophils to generate NETs. Finally, tissue microarray (TMA) for LUAD patients verified the prognostic value of PLSCR1 expression. In this study, we focus on emerging hot topic NETs in LUAD. We provide a prognostic NETs signature and identify PLSCR1 with multiple roles in LUAD. This work can contribute to risk stratification and screen novel therapeutic targets for LUAD patients.
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Affiliation(s)
- A Xuan Han
- Department of General Surgery, Aerospace Central Hospital, 15 Yuquan Road, Haidian District, Beijing, China
| | - B Yaping Long
- Department of Medical Oncology, Senior Department of Oncology, Fengtai District, The Fifth Medical Center of PLA General Hospital, No. 100, West Fourth Ring Middle Road, Beijing, 100039, China
- School of Medicine, Nankai University, Nankai District, 94 Weijin Road, Tianjin, 300071, China
| | - C Yao Li
- Department of Medical Oncology, Senior Department of Oncology, Fengtai District, The Fifth Medical Center of PLA General Hospital, No. 100, West Fourth Ring Middle Road, Beijing, 100039, China
- Medical School of Chinese People's Liberation Army (PLA), Haidian District, 28 Fuxing Road, Beijing, 100853, People's Republic of China
| | - D Di Huang
- Department of Medical Oncology, Senior Department of Oncology, Fengtai District, The Fifth Medical Center of PLA General Hospital, No. 100, West Fourth Ring Middle Road, Beijing, 100039, China
| | - E Qi Xiong
- Department of Medical Oncology, Senior Department of Oncology, Fengtai District, The Fifth Medical Center of PLA General Hospital, No. 100, West Fourth Ring Middle Road, Beijing, 100039, China
| | - F Jinfeng Li
- Institute of Oncology, The First Medical Center of Chinese, PLA General Hospital, Beijing, 100853, China
| | - G Liangliang Wu
- Institute of Oncology, The First Medical Center of Chinese, PLA General Hospital, Beijing, 100853, China
| | - Qiaowei Liu
- Department of Medical Oncology, Senior Department of Oncology, Fengtai District, The Fifth Medical Center of PLA General Hospital, No. 100, West Fourth Ring Middle Road, Beijing, 100039, China.
- Department of Emergency, Senior Department of Oncology, The Fifth Medical Center of PLA General Hospital, 8 Dongdajie Road, Fengtai District, Beijing, 100071, China.
| | - G Bo Yang
- Department of Medical Oncology, Senior Department of Oncology, Fengtai District, The Fifth Medical Center of PLA General Hospital, No. 100, West Fourth Ring Middle Road, Beijing, 100039, China.
| | - H Yi Hu
- Department of Medical Oncology, Senior Department of Oncology, Fengtai District, The Fifth Medical Center of PLA General Hospital, No. 100, West Fourth Ring Middle Road, Beijing, 100039, China.
- School of Medicine, Nankai University, Nankai District, 94 Weijin Road, Tianjin, 300071, China.
- Medical School of Chinese People's Liberation Army (PLA), Haidian District, 28 Fuxing Road, Beijing, 100853, People's Republic of China.
- Institute of Oncology, The First Medical Center of Chinese, PLA General Hospital, Beijing, 100853, China.
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6
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Ye Z, Galvanetto N, Puppulin L, Pifferi S, Flechsig H, Arndt M, Triviño CAS, Di Palma M, Guo S, Vogel H, Menini A, Franz CM, Torre V, Marchesi A. Structural heterogeneity of the ion and lipid channel TMEM16F. Nat Commun 2024; 15:110. [PMID: 38167485 PMCID: PMC10761740 DOI: 10.1038/s41467-023-44377-7] [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: 02/13/2023] [Accepted: 12/11/2023] [Indexed: 01/05/2024] Open
Abstract
Transmembrane protein 16 F (TMEM16F) is a Ca2+-activated homodimer which functions as an ion channel and a phospholipid scramblase. Despite the availability of several TMEM16F cryogenic electron microscopy (cryo-EM) structures, the mechanism of activation and substrate translocation remains controversial, possibly due to restrictions in the accessible protein conformational space. In this study, we use atomic force microscopy under physiological conditions to reveal a range of structurally and mechanically diverse TMEM16F assemblies, characterized by variable inter-subunit dimerization interfaces and protomer orientations, which have escaped prior cryo-EM studies. Furthermore, we find that Ca2+-induced activation is associated to stepwise changes in the pore region that affect the mechanical properties of transmembrane helices TM3, TM4 and TM6. Our direct observation of membrane remodelling in response to Ca2+ binding along with additional electrophysiological analysis, relate this structural multiplicity of TMEM16F to lipid and ion permeation processes. These results thus demonstrate how conformational heterogeneity of TMEM16F directly contributes to its diverse physiological functions.
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Affiliation(s)
- Zhongjie Ye
- International School for Advanced Studies (SISSA), 34136, Trieste, Italy
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 518055, Shenzhen, China
| | - Nicola Galvanetto
- Department of Physics, University of Zurich, 8057, Zurich, Switzerland
- Department of Biochemistry, University of Zurich, 8057, Zurich, Switzerland
| | - Leonardo Puppulin
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, I-30172 Mestre, Venice, Italy
- WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, 920-1192, Kanazawa, Japan
| | - Simone Pifferi
- International School for Advanced Studies (SISSA), 34136, Trieste, Italy
- Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, 60126, Ancona, Italy
| | - Holger Flechsig
- WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, 920-1192, Kanazawa, Japan
| | - Melanie Arndt
- Department of Biochemistry, University of Zurich, 8057, Zurich, Switzerland
| | | | - Michael Di Palma
- Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, 60126, Ancona, Italy
| | - Shifeng Guo
- Shenzhen Key Laboratory of Smart Sensing and Intelligent Systems, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
- Guangdong Provincial Key Lab of Robotics and Intelligent System, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Horst Vogel
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 518055, Shenzhen, China
- Institut des Sciences et Ingénierie Chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Anna Menini
- International School for Advanced Studies (SISSA), 34136, Trieste, Italy
| | - Clemens M Franz
- WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, 920-1192, Kanazawa, Japan
| | - Vincent Torre
- International School for Advanced Studies (SISSA), 34136, Trieste, Italy.
- Institute of Materials (ION-CNR), Area Science Park, Basovizza, 34149, Trieste, Italy.
- BIoValley Investments System and Solutions (BISS), 34148, Trieste, Italy.
| | - Arin Marchesi
- WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, 920-1192, Kanazawa, Japan.
- Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, 60126, Ancona, Italy.
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7
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Rydström A, Grahn THM, Niroula A, Mansell E, van der Garde M, Pertesi M, Subramaniam A, Soneji S, Zubarev R, Enver T, Nilsson B, Miharada K, Larsson J, Karlsson S. Functional and molecular profiling of hematopoietic stem cells during regeneration. Exp Hematol 2023; 127:40-51. [PMID: 37666355 DOI: 10.1016/j.exphem.2023.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/06/2023]
Abstract
Hematopoietic stem cells (HSCs) enable hematopoietic stem cell transplantation (HCT) through their ability to replenish the entire blood system. Proliferation of HSCs is linked to decreased reconstitution potential, and a precise regulation of actively dividing HSCs is thus essential to ensure long-term functionality. This regulation becomes important in the transplantation setting where HSCs undergo proliferation followed by a gradual transition to quiescence and homeostasis. Although mouse HSCs have been well studied under homeostatic conditions, the mechanisms regulating HSC activation under stress remain unclear. Here, we analyzed the different phases of regeneration after transplantation. We isolated bone marrow from mice at 8 time points after transplantation and examined the reconstitution dynamics and transcriptional profiles of stem and progenitor populations. We found that regenerating HSCs initially produced rapidly expanding progenitors and displayed distinct changes in fatty acid metabolism and glycolysis. Moreover, we observed molecular changes in cell cycle, MYC and mTOR signaling in both HSCs, and progenitor subsets. We used a decay rate model to fit the temporal transcription profiles of regenerating HSCs and identified genes with progressively decreased or increased expression after transplantation. These genes overlapped to a large extent with published gene sets associated with key aspects of HSC function, demonstrating the potential of this data set as a resource for identification of novel HSC regulators. Taken together, our study provides a detailed functional and molecular characterization of HSCs at different phases of regeneration and identifies a gene set associated with the transition from proliferation to quiescence.
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Affiliation(s)
- Anna Rydström
- Molecular Medicine and Gene Therapy, Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Tan H M Grahn
- Molecular Medicine and Gene Therapy, Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Abhishek Niroula
- Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Els Mansell
- Molecular Medicine and Gene Therapy, Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Mark van der Garde
- Molecular Medicine and Gene Therapy, Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Maroulio Pertesi
- Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | | | - Shamit Soneji
- Division of Molecular Hematology, Department of Laboratory Medicine, Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Roman Zubarev
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Solna, Sweden
| | - Tariq Enver
- Stem Cell Group, Cancer Institute, University College London, United Kingdom
| | - Björn Nilsson
- Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Kenichi Miharada
- Molecular Medicine and Gene Therapy, Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Jonas Larsson
- Molecular Medicine and Gene Therapy, Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Stefan Karlsson
- Molecular Medicine and Gene Therapy, Lund Stem Cell Center, Lund University, Lund, Sweden.
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8
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Rosewood TJ, Nho K, Risacher SL, Gao S, Shen L, Foroud T, Saykin AJ. Genome-Wide Association Analysis across Endophenotypes in Alzheimer's Disease: Main Effects and Disease Stage-Specific Interactions. Genes (Basel) 2023; 14:2010. [PMID: 38002954 PMCID: PMC10671827 DOI: 10.3390/genes14112010] [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: 09/11/2023] [Revised: 10/23/2023] [Accepted: 10/23/2023] [Indexed: 11/26/2023] Open
Abstract
The underlying genetic susceptibility for Alzheimer's disease (AD) is not yet fully understood. The heterogeneous nature of the disease challenges genetic association studies. Endophenotype approaches can help to address this challenge by more direct interrogation of biological traits related to the disease. AD endophenotypes based on amyloid-β, tau, and neurodegeneration (A/T/N) biomarkers and cognitive performance were selected from the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort (N = 1565). A genome-wide association study (GWAS) of quantitative phenotypes was performed using an SNP main effect and an SNP by Diagnosis interaction (SNP × DX) model to identify disease stage-specific genetic effects. Nine loci were identified as study-wide significant with one or more A/T/N endophenotypes in the main effect model, as well as additional findings significantly associated with cognitive measures. These nine loci include SNPs in or near the genes APOE, SRSF10, HLA-DQB1, XKR3, and KIAA1671. The SNP × DX model identified three study-wide significant genetic loci (BACH2, EP300, and PACRG-AS1) with a neuroprotective effect in later AD stage endophenotypes. An endophenotype approach identified novel genetic associations and provided insight into the molecular mechanisms underlying the genetic associations that may otherwise be missed using conventional case-control study designs.
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Affiliation(s)
- Thea J. Rosewood
- Indiana Alzheimer’s Disease Research Center, Indianapolis, IN 46202, USA; (T.J.R.); (S.L.R.); (S.G.); (T.F.)
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Kwangsik Nho
- Indiana Alzheimer’s Disease Research Center, Indianapolis, IN 46202, USA; (T.J.R.); (S.L.R.); (S.G.); (T.F.)
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- School of Informatics and Computing, Indiana University, Indianapolis, IN 46202, USA
| | - Shannon L. Risacher
- Indiana Alzheimer’s Disease Research Center, Indianapolis, IN 46202, USA; (T.J.R.); (S.L.R.); (S.G.); (T.F.)
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Sujuan Gao
- Indiana Alzheimer’s Disease Research Center, Indianapolis, IN 46202, USA; (T.J.R.); (S.L.R.); (S.G.); (T.F.)
- Department of Biostatistics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Li Shen
- Department of Biostatistics, Epidemiology and Informatics, The Perelman School of Medicine, Philadelphia, PA 19104, USA;
| | - Tatiana Foroud
- Indiana Alzheimer’s Disease Research Center, Indianapolis, IN 46202, USA; (T.J.R.); (S.L.R.); (S.G.); (T.F.)
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Andrew J. Saykin
- Indiana Alzheimer’s Disease Research Center, Indianapolis, IN 46202, USA; (T.J.R.); (S.L.R.); (S.G.); (T.F.)
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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9
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Sperrhacke M, Leitzke S, Ahrens B, Reiss K. Breakdown of Phospholipid Asymmetry Triggers ADAM17-Mediated Rescue Events in Cells Undergoing Apoptosis. MEMBRANES 2023; 13:720. [PMID: 37623781 PMCID: PMC10456294 DOI: 10.3390/membranes13080720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/27/2023] [Accepted: 08/03/2023] [Indexed: 08/26/2023]
Abstract
ADAM17, a prominent member of the "Disintegrin and Metalloproteinase" (ADAM) family, controls vital cellular functions through the cleavage of transmembrane substrates, including epidermal growth factor receptor (EGFR) ligands such as transforming growth factor (TGF)-alpha and Epiregulin (EREG). Several ADAM17 substrates are relevant to oncogenesis and tumor growth. We have presented evidence that surface exposure of phosphatidylserine (PS) is pivotal for ADAM17 to exert sheddase activity. The scramblase Xkr8 is instrumental for calcium-independent exposure of PS in apoptotic cells. Xkr8 can be dually activated by caspase-3 and by kinases. In this investigation, we examined whether Xkr8 would modulate ADAM17 activity under apoptotic and non-apoptotic conditions. Overexpression of Xkr8 in HEK293T cells led to significantly increased caspase-dependent as well as PMA-induced release of EREG and TGF-alpha. Conversely, siRNA-mediated downregulation of Xkr8 in colorectal Caco-2 cancer cells led to decreased PS externalization upon induction of apoptosis, which was accompanied by reduced shedding of endogenously expressed EREG and reduced cell survival. We conclude that Xkr8 shares with conventional scramblases the propensity to upmodulate the ADAM-sheddase function. Liberation of growth factors could serve a rescue function in cells on the pathway to apoptotic death.
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Affiliation(s)
| | | | | | - Karina Reiss
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany (B.A.)
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10
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Nissa MU, Pinto N, Ghosh B, Singh U, Goswami M, Srivastava S. Proteomic analysis of liver tissue reveals Aeromonas hydrophila infection mediated modulation of host metabolic pathways in Labeo rohita. J Proteomics 2023; 279:104870. [PMID: 36906258 DOI: 10.1016/j.jprot.2023.104870] [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: 12/29/2022] [Revised: 02/20/2023] [Accepted: 03/04/2023] [Indexed: 03/11/2023]
Abstract
Aeromonas hydrophila (Ah) is a Gram-negative bacterium and a serious global pathogen causing Motile Aeromonas Septicaemia (MAS) in fish leading to global loss in aquaculture. Investigation of the molecular alterations of host tissues such as liver could be a powerful approach to identify mechanistic and diagnostic immune signatures of disease pathogenesis. We performed a proteomic analysis of Labeo rohita liver tissue to examine the protein dynamics in the host cells during Ah infection. The proteomic data was acquired using two strategies; discovery and targeted proteomics. Label-free quantification was performed between Control and challenged group (AH) to identify the differentially expressed proteins (DEPs). A total of 2525 proteins were identified and 157 were DEPs. DEPs include metabolic enzymes (CS, SUCLG2), antioxidative proteins, cytoskeletal proteins and immune related proteins (TLR3, CLEC4E). Pathways like lysosome pathway, apoptosis, metabolism of xenobiotics by cytochrome P450 were enriched by downregulated proteins. However, upregulated proteins majorly mapped to innate immune system, signaling of B cell receptor, proteosome pathway, ribosome, carbon metabolism and protein processing in ER. Our study would help in exploring the role of Toll-like receptors, C-type lectins and, metabolic intermediates like citrate and succinate in Ah pathogenesis to understand the Ah infection in fish. SIGNIFICANCE: Bacterial diseases such as motile aeromonas septicaemia (MAS) are among the most serious problems in aquaculture industry. Small molecules that target the metabolism of the host have recently emerged as potential treatment possibilities in infectious diseases. However, the ability to develop new therapies is hampered due to lack of knowledge about pathogenesis mechanisms and host-pathogen interactions. We examined alterations in the host proteome during MAS caused by Aeromonas hydrophila (Ah) infection, in Labeo rohita liver tissue to find cellular proteins and processes affected by Ah infection. Upregulated proteins belong to innate immune system, signaling of B cell receptor, proteosome pathway, ribosome, carbon metabolism and protein processing. Our work is an important step towards leveraging host metabolism in targeting the disease by providing a bigger picture on proteome pathology correlation during Ah infection.
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Affiliation(s)
- Mehar Un Nissa
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Nevil Pinto
- Central Institute of Fisheries Education, Indian Council of Agricultural Research, Versova, Mumbai, Maharashtra 400061, India
| | - Biplab Ghosh
- Regional Centre for Biotechnology, Faridabad 121001, India
| | - Urvi Singh
- Department of Biochemistry, Sri Venkateswara College, University of Delhi, 110034, India
| | - Mukunda Goswami
- Central Institute of Fisheries Education, Indian Council of Agricultural Research, Versova, Mumbai, Maharashtra 400061, India.
| | - Sanjeeva Srivastava
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
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11
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Al Badri YN, Chaw CS, Elkordy AA. Insights into Asymmetric Liposomes as a Potential Intervention for Drug Delivery Including Pulmonary Nanotherapeutics. Pharmaceutics 2023; 15:pharmaceutics15010294. [PMID: 36678922 PMCID: PMC9867527 DOI: 10.3390/pharmaceutics15010294] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/22/2022] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
Liposome-based drug delivery systems are nanosized spherical lipid bilayer carriers that can encapsulate a broad range of small drug molecules (hydrophilic and hydrophobic drugs) and large drug molecules (peptides, proteins, and nucleic acids). They have unique characteristics, such as a self-assembling bilayer vesicular structure. There are several FDA-approved liposomal-based medicines for treatment of cancer, bacterial, and viral infections. Most of the FDA-approved liposomal-based therapies are in the form of conventional "symmetric" liposomes and they are administered mainly by injection. Arikace® is the first and only FDA-approved liposomal-based inhalable therapy (amikacin liposome inhalation suspension) to treat only adults with difficult-to-treat Mycobacterium avium complex (MAC) lung disease as a combinational antibacterial treatment. To date, no "asymmetric liposomes" are yet to be approved, although asymmetric liposomes have many advantages due to the asymmetric distribution of lipids through the liposome's membrane (which is similar to the biological membranes). There are many challenges for the formulation and stability of asymmetric liposomes. This review will focus on asymmetric liposomes in contrast to conventional liposomes as a potential clinical intervention drug delivery system as well as the formulation techniques available for symmetric and asymmetric liposomes. The review aims to renew the research in liposomal nanovesicle delivery systems with particular emphasis on asymmetric liposomes as future potential carriers for enhancing drug delivery including pulmonary nanotherapeutics.
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Affiliation(s)
| | | | - Amal Ali Elkordy
- Correspondence: ; Tel.: +44-(0)-1915152576; Fax: +44-(0)-1915153405
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12
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Cellular function of (a)symmetric biological membranes. Emerg Top Life Sci 2022; 7:47-54. [PMID: 36562339 DOI: 10.1042/etls20220029] [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: 10/18/2022] [Revised: 11/26/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022]
Abstract
In mammalian cells, phospholipids are asymmetrically distributed between the outer and inner leaflets of the plasma membrane. The maintenance of asymmetric phospholipid distribution has been demonstrated to be required for a wide range of cellular functions including cell division, cell migration, and signal transduction. However, we recently reported that asymmetric phospholipid distribution is disrupted in Drosophila cell membranes, and this unique phospholipid distribution leads to the formation of highly deformable cell membranes. In addition, it has become clear that asymmetry in the trans-bilayer distribution of phospholipids is disturbed even in living mammalian cells under certain circumstances. In this article, we introduce our recent studies while focusing on the trans-bilayer distribution of phospholipids, and discuss the cellular functions of (a)symmetric biological membranes.
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13
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Mansuri S, Mukherjee T, Kanvah S. Fluorescent sterol probes for intracellular transport, imaging, and therapeutics. Curr Opin Chem Biol 2022; 71:102222. [PMID: 36219959 DOI: 10.1016/j.cbpa.2022.102222] [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: 07/28/2022] [Revised: 09/01/2022] [Accepted: 09/12/2022] [Indexed: 01/27/2023]
Abstract
Sterols play a significant role in many physiological processes affecting membrane organization, transport, permeability, and signal transduction. The development of fluorescent sterol analogs that have immediate functional relevance to the natural biomolecules is one approach to understanding the sterol-driven physiological processes. Visualizing cellular compartments with tailor-made fluorescent molecules through specific labeling methods enables organelle targeting and reveals dynamic information. In this review, we focus on the recent literature published between 2020 and 2022, with particular emphasis on extrinsic fluorophores and their investigations of sterol-driven biological processes involving sterol transport, biomolecular interactions, and biological imaging.
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Affiliation(s)
- Shabnam Mansuri
- Department of Chemistry, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat, 382055, India
| | - Tarushyam Mukherjee
- Department of Chemistry, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat, 382055, India
| | - Sriram Kanvah
- Department of Chemistry, Indian Institute of Technology Gandhinagar, Gandhinagar, Gujarat, 382055, India.
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14
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Tang D, Wang Y, Dong X, Yuan Y, Kang F, Tian W, Wang K, Li H, Qi S. Scramblases and virus infection. Bioessays 2022; 44:e2100261. [DOI: 10.1002/bies.202100261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Dan Tang
- Department of Urology Institute of Urology (Laboratory of Reconstructive Urology) State Key Laboratory of Oral Disease West China Hospital of Stomatology West China Hospital Sichuan University Chengdu Sichuan China
| | - Yichang Wang
- Department of Urology Institute of Urology (Laboratory of Reconstructive Urology) State Key Laboratory of Oral Disease West China Hospital of Stomatology West China Hospital Sichuan University Chengdu Sichuan China
| | - Xiuju Dong
- Department of Urology Institute of Urology (Laboratory of Reconstructive Urology) State Key Laboratory of Oral Disease West China Hospital of Stomatology West China Hospital Sichuan University Chengdu Sichuan China
| | - Yiqiong Yuan
- Department of Urology Institute of Urology (Laboratory of Reconstructive Urology) State Key Laboratory of Oral Disease West China Hospital of Stomatology West China Hospital Sichuan University Chengdu Sichuan China
| | - Fanchen Kang
- Department of Urology Institute of Urology (Laboratory of Reconstructive Urology) State Key Laboratory of Oral Disease West China Hospital of Stomatology West China Hospital Sichuan University Chengdu Sichuan China
| | - Weidong Tian
- Department of Urology Institute of Urology (Laboratory of Reconstructive Urology) State Key Laboratory of Oral Disease West China Hospital of Stomatology West China Hospital Sichuan University Chengdu Sichuan China
| | - Kunjie Wang
- Department of Urology Institute of Urology (Laboratory of Reconstructive Urology) State Key Laboratory of Oral Disease West China Hospital of Stomatology West China Hospital Sichuan University Chengdu Sichuan China
| | - Hong Li
- Department of Urology Institute of Urology (Laboratory of Reconstructive Urology) State Key Laboratory of Oral Disease West China Hospital of Stomatology West China Hospital Sichuan University Chengdu Sichuan China
| | - Shiqian Qi
- Department of Urology Institute of Urology (Laboratory of Reconstructive Urology) State Key Laboratory of Oral Disease West China Hospital of Stomatology West China Hospital Sichuan University Chengdu Sichuan China
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15
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Barth LAG, Nebe M, Kalwa H, Velluva A, Kehr S, Kolbig F, Prabutzki P, Kiess W, Le Duc D, Garten A, Kirstein AS. Phospholipid Scramblase 4 (PLSCR4) Regulates Adipocyte Differentiation via PIP3-Mediated AKT Activation. Int J Mol Sci 2022; 23:ijms23179787. [PMID: 36077184 PMCID: PMC9456373 DOI: 10.3390/ijms23179787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/18/2022] [Accepted: 08/24/2022] [Indexed: 11/16/2022] Open
Abstract
Phospholipid scramblase 4 (PLSCR4) is a member of a conserved enzyme family with high relevance for the remodeling of phospholipid distribution in the plasma membrane and the regulation of cellular signaling. While PLSCR1 and -3 are involved in the regulation of adipose-tissue expansion, the role of PLSCR4 is so far unknown. PLSCR4 is significantly downregulated in an adipose-progenitor-cell model of deficiency for phosphatase and tensin homolog (PTEN). PTEN acts as a tumor suppressor and antagonist of the growth and survival signaling phosphoinositide 3-kinase (PI3K)/AKT cascade by dephosphorylating phosphatidylinositol-3,4,5-trisphosphate (PIP3). Patients with PTEN germline deletion frequently develop lipomas. The underlying mechanism for this aberrant adipose-tissue growth is incompletely understood. PLSCR4 is most highly expressed in human adipose tissue, compared with other phospholipid scramblases, suggesting a specific role of PLSCR4 in adipose-tissue biology. In cell and mouse models of lipid accumulation, we found PLSCR4 to be downregulated. We observed increased adipogenesis in PLSCR4-knockdown adipose progenitor cells, while PLSCR4 overexpression attenuated lipid accumulation. PLSCR4 knockdown was associated with increased PIP3 levels and the activation of AKT. Our results indicated that PLSCR4 is a regulator of PI3K/AKT signaling and adipogenesis and may play a role in PTEN-associated adipose-tissue overgrowth and lipoma formation.
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Affiliation(s)
- Lisa A. G. Barth
- University Hospital for Children & Adolescents, Center for Pediatric Research, Leipzig University, 04103 Leipzig, Germany
| | - Michèle Nebe
- University Hospital for Children & Adolescents, Center for Pediatric Research, Leipzig University, 04103 Leipzig, Germany
| | - Hermann Kalwa
- Institute of Pharmacology, Pharmacy and Toxicology, Leipzig University, 04107 Leipzig, Germany
| | - Akhil Velluva
- Institute of Human Genetics, Leipzig University Medical Center, 04103 Leipzig, Germany
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
| | - Stephanie Kehr
- Bioinformatics Group, Department of Computer Science, Interdisciplinary Center for Bioinformatics, Leipzig University, 04107 Leipzig, Germany
| | - Florentien Kolbig
- University Hospital for Children & Adolescents, Center for Pediatric Research, Leipzig University, 04103 Leipzig, Germany
| | - Patricia Prabutzki
- Institute for Medical Physics and Biophysics, Leipzig University, 04107 Leipzig, Germany
| | - Wieland Kiess
- University Hospital for Children & Adolescents, Center for Pediatric Research, Leipzig University, 04103 Leipzig, Germany
| | - Diana Le Duc
- Institute of Human Genetics, Leipzig University Medical Center, 04103 Leipzig, Germany
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, 04103 Leipzig, Germany
| | - Antje Garten
- University Hospital for Children & Adolescents, Center for Pediatric Research, Leipzig University, 04103 Leipzig, Germany
| | - Anna S. Kirstein
- University Hospital for Children & Adolescents, Center for Pediatric Research, Leipzig University, 04103 Leipzig, Germany
- Correspondence: ; Tel.: +49-341-972-6504
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16
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Dal Col J, Lamberti MJ, Nigro A, Casolaro V, Fratta E, Steffan A, Montico B. Phospholipid scramblase 1: a protein with multiple functions via multiple molecular interactors. Cell Commun Signal 2022; 20:78. [PMID: 35650588 PMCID: PMC9158361 DOI: 10.1186/s12964-022-00895-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 04/30/2022] [Indexed: 01/18/2023] Open
Abstract
Phospholipid scramblase 1 (PLSCR1) is the most studied protein of the scramblase family. Originally, it was identified as a membrane protein involved in maintaining plasma membrane asymmetry. However, studies conducted over the past few years have shown the involvement of PLSCR1 in several other cellular pathways. Indeed, PLSCR1 is not only embedded in the plasma membrane but is also expressed in several intracellular compartments where it interacts with a diverse repertoire of effectors, mediators, and regulators contributing to distinct cellular processes. Although most PLSCR1 interactors are thought to be cell-type specific, PLSCR1 often exerts its regulatory functions through shared mechanisms, including the trafficking of different molecules within intracellular vesicles such as endosomes, liposomes, and phagosomes. Intriguingly, besides endogenous proteins, PLSCR1 was also reported to interact with exogenous viral proteins, thereby regulating viral uptake and spread. This review aims to summarize the current knowledge about the multiple roles of PLSCR1 in distinct cellular pathways. Video Abstract
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Affiliation(s)
- Jessica Dal Col
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Baronissi, Italy.
| | - Marìa Julia Lamberti
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Baronissi, Italy.,INBIAS, CONICET-UNRC, Río Cuarto, Córdoba, Argentina
| | - Annunziata Nigro
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Baronissi, Italy
| | - Vincenzo Casolaro
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Baronissi, Italy
| | - Elisabetta Fratta
- Division of Immunopathology and Cancer Biomarkers, Centro Di Riferimento Oncologico di Aviano (CRO), IRCCS, Aviano, Italy
| | - Agostino Steffan
- Division of Immunopathology and Cancer Biomarkers, Centro Di Riferimento Oncologico di Aviano (CRO), IRCCS, Aviano, Italy
| | - Barbara Montico
- Division of Immunopathology and Cancer Biomarkers, Centro Di Riferimento Oncologico di Aviano (CRO), IRCCS, Aviano, Italy.
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17
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Luo J, Lian Q, Zhu D, Zhao M, Mei T, Shang B, Yang Z, Liu C, Xu W, Zhou L, Wu K, Liu X, Lai Y, Mao F, Li W, Zuo C, Zhang K, Lin M, Zhuo Y, Liu Y, Lu L, Zhao L. PLSCR1 Promotes Apoptosis and Clearance of Retinal Ganglion Cells in Glaucoma Pathogenesis. Genes Dis 2022. [DOI: 10.1016/j.gendis.2022.05.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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18
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Lipid Dyshomeostasis and Inherited Cerebellar Ataxia. Mol Neurobiol 2022; 59:3800-3828. [PMID: 35420383 PMCID: PMC9148275 DOI: 10.1007/s12035-022-02826-2] [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: 03/29/2021] [Accepted: 04/01/2022] [Indexed: 12/04/2022]
Abstract
Cerebellar ataxia is a form of ataxia that originates from dysfunction of the cerebellum, but may involve additional neurological tissues. Its clinical symptoms are mainly characterized by the absence of voluntary muscle coordination and loss of control of movement with varying manifestations due to differences in severity, in the site of cerebellar damage and in the involvement of extracerebellar tissues. Cerebellar ataxia may be sporadic, acquired, and hereditary. Hereditary ataxia accounts for the majority of cases. Hereditary ataxia has been tentatively divided into several subtypes by scientists in the field, and nearly all of them remain incurable. This is mainly because the detailed mechanisms of these cerebellar disorders are incompletely understood. To precisely diagnose and treat these diseases, studies on their molecular mechanisms have been conducted extensively in the past. Accumulating evidence has demonstrated that some common pathogenic mechanisms exist within each subtype of inherited ataxia. However, no reports have indicated whether there is a common mechanism among the different subtypes of inherited cerebellar ataxia. In this review, we summarize the available references and databases on neurological disorders characterized by cerebellar ataxia and show that a subset of genes involved in lipid homeostasis form a new group that may cause ataxic disorders through a common mechanism. This common signaling pathway can provide a valuable reference for future diagnosis and treatment of ataxic disorders.
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19
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Coenzyme A Restriction as a Factor Underlying Pre-Eclampsia with Polycystic Ovary Syndrome as a Risk Factor. Int J Mol Sci 2022; 23:ijms23052785. [PMID: 35269927 PMCID: PMC8911031 DOI: 10.3390/ijms23052785] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 02/24/2022] [Indexed: 02/07/2023] Open
Abstract
Pre-eclampsia is the most common pregnancy complication affecting 1 in 20 pregnancies, characterized by high blood pressure and signs of organ damage, most often to the liver and kidneys. Metabolic network analysis of published lipidomic data points to a shortage of Coenzyme A (CoA). Gene expression profile data reveal alterations to many areas of metabolism and, crucially, to conflicting cellular regulatory mechanisms arising from the overproduction of signalling lipids driven by CoA limitation. Adverse feedback loops appear, forming sphingosine-1-phosphate (a cause of hypertension, hypoxia and inflammation), cytotoxic isoketovaleric acid (inducing acidosis and organ damage) and a thrombogenic lysophosphatidyl serine. These also induce mitochondrial and oxidative stress, leading to untimely apoptosis, which is possibly the cause of CoA restriction. This work provides a molecular basis for the signs of pre-eclampsia, why polycystic ovary syndrome is a risk factor and what might be done to treat and reduce the risk of disease.
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20
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Tang JC, Lee CH, Lu T, Vankayala R, Hanley T, Azubuogu C, Li J, Nair MG, Jia W, Anvari B. Membrane Cholesterol Enrichment of Red Blood Cell-Derived Microparticles Results in Prolonged Circulation. ACS APPLIED BIO MATERIALS 2022; 5:650-660. [PMID: 35006664 PMCID: PMC9924066 DOI: 10.1021/acsabm.1c01104] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Particles fabricated from red blood cells (RBCs) can serve as vehicles for delivery of various biomedical cargos. Flipping of phosphatidylserine (PS) from the inner to the outer membrane leaflet normally occurs during the fabrication of such particles. PS externalization is a signal for phagocytic removal of the particles from circulation. Herein, we demonstrate that membrane cholesterol enrichment can mitigate the outward display of PS on microparticles engineered from RBCs. Our in-vitro results show that the phagocytic uptake of cholesterol-enriched particles by murine macrophages takes place at a lowered rate, resulting in reduced uptake as compared to RBC-derived particles without cholesterol enrichment. When administered via tail-vein injection into healthy mice, the percent of injected dose (ID) per gram of extracted blood for cholesterol-enriched particles was ∼1.5 and 1.8 times higher than the particles without cholesterol enrichment at 4 and 24 h, respectively. At 24 h, ∼43% ID/g of the particles without cholesterol enrichment was eliminated or metabolized while ∼94% ID/g of the cholesterol-enriched particles were still retained in the body. These results indicate that membrane cholesterol enrichment is an effective method to reduce PS externalization on the surface of RBC-derived particles and increase their longevity in circulation.
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Affiliation(s)
- Jack C. Tang
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States; Present Address: University of Southern California, Los Angeles, California 90033, United States
| | - Chi-Hua Lee
- Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
| | - Thompson Lu
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States
| | - Raviraj Vankayala
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States; Present Address: Indian Institute of Technology Jodhpur, Karwar, Jodhpur, Rajasthan 342037, India
| | - Taylor Hanley
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States
| | - Chiemerie Azubuogu
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92023, United States
| | - Jiang Li
- Division of Biomedical Sciences, University of California, Riverside, Riverside, California 92521, United States
| | - Meera G. Nair
- Division of Biomedical Sciences, University of California, Riverside, Riverside, California 92521, United States
| | - Wangcun Jia
- Beckman Laser Institute & Medical Clinic, University of California, Irvine, Irvine, California 92617, United States
| | - Bahman Anvari
- Department of Bioengineering and Department of Biochemistry, University of California, Riverside, Riverside, California 92521, United States
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21
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Scramblases as Regulators of Proteolytic ADAM Function. MEMBRANES 2022; 12:membranes12020185. [PMID: 35207106 PMCID: PMC8880048 DOI: 10.3390/membranes12020185] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/25/2022] [Accepted: 02/02/2022] [Indexed: 11/16/2022]
Abstract
Proteolytic ectodomain release is a key mechanism for regulating the function of many cell surface proteins. The sheddases ADAM10 and ADAM17 are the best-characterized members of the family of transmembrane disintegrin-like metalloproteinase. Constitutive proteolytic activities are low but can be abruptly upregulated via inside-out signaling triggered by diverse activating events. Emerging evidence indicates that the plasma membrane itself must be assigned a dominant role in upregulation of sheddase function. Data are discussed that tentatively identify phospholipid scramblases as central players during these events. We propose that scramblase-dependent externalization of the negatively charged phospholipid phosphatidylserine (PS) plays an important role in the final activation step of ADAM10 and ADAM17. In this manuscript, we summarize the current knowledge on the interplay of cell membrane changes, PS exposure, and proteolytic activity of transmembrane proteases as well as the potential consequences in the context of immune response, infection, and cancer. The novel concept that scramblases regulate the action of ADAM-proteases may be extendable to other functional proteins that act at the cell surface.
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22
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Leitzke S, Seidel J, Ahrens B, Schreiber R, Kunzelmann K, Sperrhacke M, Bhakdi S, Reiss K. Influence of Anoctamin-4 and -9 on ADAM10 and ADAM17 Sheddase Function. MEMBRANES 2022; 12:membranes12020123. [PMID: 35207044 PMCID: PMC8879676 DOI: 10.3390/membranes12020123] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 02/04/2023]
Abstract
Ca2+-activated Cl− channels (TMEM16, also known as anoctamins) perform important functions in cell physiology, including modulation of cell proliferation and cancer growth. Many members, including TMEM16F/ANO6, additionally act as Ca2+-activated phospholipid scramblases. We recently presented evidence that ANO6-dependent surface exposure of phosphatidylserine (PS) is pivotal for the disintegrin-like metalloproteases ADAM10 and ADAM17 to exert their sheddase function. Here, we compared the influence of seven ANO family members (ANO1, 4, 5, 6, 7, 9, and 10) on ADAM sheddase activity. Similar to ANO6, overexpression of ANO4 and ANO9 led to increased release of ADAM10 and ADAM17 substrates, such as betacellulin, TGFα, and amphiregulin (AREG), upon ionophore stimulation in HEK cells. Inhibitor experiments indicated that ANO4/ANO9-mediated enhancement of TGFα-cleavage broadened the spectrum of participating metalloproteinases. Annexin V-staining demonstrated increased externalisation of PS in ANO4/ANO9-overexpressing cells. Competition experiments with the soluble PS-headgroup phosphorylserine indicated that the ANO4/ANO9 effects were due to increased PS exposure. Overexpression of ANO4 or ANO9 in human cervical cancer cells (HeLa), enhanced constitutive shedding of the growth factor AREG and increased cell proliferation. We conclude that ANO4 and ANO9, by virtue of their scramblase activity, may play a role as important regulators of ADAM-dependent cellular functions.
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Affiliation(s)
- Sinje Leitzke
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (S.L.); (J.S.); (B.A.); (M.S.)
| | - Jana Seidel
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (S.L.); (J.S.); (B.A.); (M.S.)
| | - Björn Ahrens
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (S.L.); (J.S.); (B.A.); (M.S.)
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany; (R.S.); (K.K.)
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany; (R.S.); (K.K.)
| | - Maria Sperrhacke
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (S.L.); (J.S.); (B.A.); (M.S.)
| | | | - Karina Reiss
- Department of Dermatology, University of Kiel, 24105 Kiel, Germany; (S.L.); (J.S.); (B.A.); (M.S.)
- Correspondence:
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Park S, Im W, Pastor RW. Developing initial conditions for simulations of asymmetric membranes: a practical recommendation. Biophys J 2021; 120:5041-5059. [PMID: 34653389 DOI: 10.1016/j.bpj.2021.10.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 05/09/2021] [Accepted: 10/08/2021] [Indexed: 01/03/2023] Open
Abstract
It has been proposed that the surface tension difference between leaflets (or differential stress) in asymmetric bilayers is generally nonvanishing. This implies that there is no unique approach to generate initial conditions for simulations of asymmetric bilayers in the absence of experimentally derived constraints. Current generation methods include individual area per lipid (APL) based, leaflet surface area (SA) matching, and zero leaflet tension based (0-DS). This work adds a bilayer-based approach that aims for achieving partial chemical equilibrium by interleaflet switching of selected lipids via P21 periodic boundary conditions. Based on a recently proposed theoretical framework, we obtained expressions for tensions in asymmetric bilayers from both the bending and area strains. We also developed a quantitative measure for the energetic penalty from the differential stress. The impacts of APL-, SA-, and 0-DS-based approaches on mechanical properties are assessed for two different asymmetric bilayers. The lateral pressure profile and its moments differ significantly for each method, whereas the area compressibility modulus is relatively insensitive. Application of P21 periodic boundary conditions (APL/P21, SA/P21, and 0-DS/P21) results in better agreement in mechanical properties between asymmetric bilayers generated by APL-, SA-, and 0-DS-based approaches, in which changes are the smallest for bilayers from the SA-based method. The estimated differential stress from the theory shows good agreement with that from the simulations. These simulation results and the good agreement between the predicted and observed differential stress further support the theoretical framework in which bilayer mechanical properties are outcomes of the interplay between intrinsic bending and asymmetric lipid packing. Based on the simulation results and theoretical predictions, the SA/P21-based, or at least the SA-based (when the differential stress is small), approach is recommended as a practical method for developing initial conditions for asymmetric bilayer simulations.
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Affiliation(s)
- Sooyhung Park
- Department of Biological Sciences, Bethlehem, Pennsylvania; Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania.
| | - Wonpil Im
- Department of Biological Sciences, Bethlehem, Pennsylvania; Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania
| | - Richard W Pastor
- Laboratory of Computational Biology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland
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24
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Cellular and molecular level host-pathogen interactions in Francisella tularensis: A microbial gene network study. Comput Biol Chem 2021; 96:107601. [PMID: 34801846 DOI: 10.1016/j.compbiolchem.2021.107601] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/12/2021] [Accepted: 11/09/2021] [Indexed: 01/17/2023]
Abstract
Due to the high infectivity and fatal effect on human population, Francisella tularensis (F. tularensis) is classified as a potential biological warfare agent. The interaction between host and pathogen behind the successful establishment of F. tularensis infection within the human host is largely unknown. In our present work, we have studied the molecular level interactions between the host cellular components and F. tularensis genes to understand the interplay between the host and pathogen. Interestingly, we have identified the pathways associated with the pathogen offensive strategies that help in invasion of host defensive systems. The F. tularensis genes purL, katG, proS, rpoB and fusA have displayed high number of interactions with the host genes and thus play a crucial role in vital pathogen pathways. The pathways identified were involved in adaptation to different stress conditions within the host and might be crucial for designing new therapeutic interventions against tularemia.
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Scott HL, Kennison KB, Enoki TA, Doktorova M, Kinnun JJ, Heberle FA, Katsaras J. Model Membrane Systems Used to Study Plasma Membrane Lipid Asymmetry. Symmetry (Basel) 2021; 13. [PMID: 35498375 PMCID: PMC9053528 DOI: 10.3390/sym13081356] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
It is well known that the lipid distribution in the bilayer leaflets of mammalian plasma membranes (PMs) is not symmetric. Despite this, model membrane studies have largely relied on chemically symmetric model membranes for the study of lipid–lipid and lipid–protein interactions. This is primarily due to the difficulty in preparing stable, asymmetric model membranes that are amenable to biophysical studies. However, in the last 20 years, efforts have been made in producing more biologically faithful model membranes. Here, we review several recently developed experimental and computational techniques for the robust generation of asymmetric model membranes and highlight a new and particularly promising technique to study membrane asymmetry.
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Affiliation(s)
- Haden L. Scott
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Kristen B. Kennison
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Thais A. Enoki
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Milka Doktorova
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Jacob J. Kinnun
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Frederick A. Heberle
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - John Katsaras
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Sample Environment Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
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26
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Haase S, Condron M, Miller D, Cherkaoui D, Jordan S, Gulbis JM, Baum J. Identification and characterisation of a phospholipid scramblase in the malaria parasite Plasmodium falciparum. Mol Biochem Parasitol 2021; 243:111374. [PMID: 33974939 PMCID: PMC8202325 DOI: 10.1016/j.molbiopara.2021.111374] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/27/2021] [Accepted: 05/06/2021] [Indexed: 02/07/2023]
Abstract
Recent studies highlight the emerging role of lipids as important messengers in malaria parasite biology. In an attempt to identify interacting proteins and regulators of these dynamic and versatile molecules, we hypothesised the involvement of phospholipid translocases and their substrates in the infection of the host erythrocyte by the malaria parasite Plasmodium spp. Here, using a data base searching approach of the Plasmodium Genomics Resources (www.plasmodb.org), we have identified a putative phospholipid (PL) scramblase in P. falciparum (PfPLSCR) that is conserved across the genus and in closely related unicellular algae. By reconstituting recombinant PfPLSCR into liposomes, we demonstrate metal ion dependent PL translocase activity and substrate preference, confirming PfPLSCR as a bona fide scramblase. We show that PfPLSCR is expressed during asexual and sexual parasite development, localising to different membranous compartments of the parasite throughout the intra-erythrocytic life cycle. Two different gene knockout approaches, however, suggest that PfPLSCR is not essential for erythrocyte invasion and asexual parasite development, pointing towards a possible role in other stages of the parasite life cycle.
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Affiliation(s)
- Silvia Haase
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK.
| | - Melanie Condron
- Division of Infection and Immunity, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
| | - David Miller
- Division of Structural Biology, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
| | - Dounia Cherkaoui
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Sarah Jordan
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK
| | - Jacqueline M Gulbis
- Division of Structural Biology, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jake Baum
- Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, Exhibition Road, South Kensington, London, UK.
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27
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Functional Interfaces, Biological Pathways, and Regulations of Interferon-Related DNA Damage Resistance Signature (IRDS) Genes. Biomolecules 2021; 11:biom11050622. [PMID: 33922087 PMCID: PMC8143464 DOI: 10.3390/biom11050622] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/15/2021] [Accepted: 04/20/2021] [Indexed: 12/14/2022] Open
Abstract
Interferon (IFN)-related DNA damage resistant signature (IRDS) genes are a subgroup of interferon-stimulated genes (ISGs) found upregulated in different cancer types, which promotes resistance to DNA damaging chemotherapy and radiotherapy. Along with briefly discussing IFNs and signalling in this review, we highlighted how different IRDS genes are affected by viruses. On the contrary, different strategies adopted to suppress a set of IRDS genes (STAT1, IRF7, OAS family, and BST2) to induce (chemo- and radiotherapy) sensitivity were deliberated. Significant biological pathways that comprise these genes were classified, along with their frequently associated genes (IFIT1/3, IFITM1, IRF7, ISG15, MX1/2 and OAS1/3/L). Major upstream regulators from the IRDS genes were identified, and different IFN types regulating these genes were outlined. Functional interfaces of IRDS proteins with DNA/RNA/ATP/GTP/NADP biomolecules featured a well-defined pharmacophore model for STAT1/IRF7-dsDNA and OAS1/OAS3/IFIH1-dsRNA complexes, as well as for the genes binding to GDP or NADP+. The Lys amino acid was found commonly interacting with the ATP phosphate group from OAS1/EIF2AK2/IFIH1 genes. Considering the premise that targeting IRDS genes mediated resistance offers an efficient strategy to resensitize tumour cells and enhances the outcome of anti-cancer treatment, this review can add some novel insights to the field.
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28
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Bencze D, Fekete T, Pázmándi K. Type I Interferon Production of Plasmacytoid Dendritic Cells under Control. Int J Mol Sci 2021; 22:ijms22084190. [PMID: 33919546 PMCID: PMC8072550 DOI: 10.3390/ijms22084190] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/11/2021] [Accepted: 04/12/2021] [Indexed: 12/11/2022] Open
Abstract
One of the most powerful and multifaceted cytokines produced by immune cells are type I interferons (IFNs), the basal secretion of which contributes to the maintenance of immune homeostasis, while their activation-induced production is essential to effective immune responses. Although, each cell is capable of producing type I IFNs, plasmacytoid dendritic cells (pDCs) possess a unique ability to rapidly produce large amounts of them. Importantly, type I IFNs have a prominent role in the pathomechanism of various pDC-associated diseases. Deficiency in type I IFN production increases the risk of more severe viral infections and the development of certain allergic reactions, and supports tumor resistance; nevertheless, its overproduction promotes autoimmune reactions. Therefore, the tight regulation of type I IFN responses of pDCs is essential to maintain an adequate level of immune response without causing adverse effects. Here, our goal was to summarize those endogenous factors that can influence the type I IFN responses of pDCs, and thus might serve as possible therapeutic targets in pDC-associated diseases. Furthermore, we briefly discuss the current therapeutic approaches targeting the pDC-type I IFN axis in viral infections, cancer, autoimmunity, and allergy, together with their limitations defined by the Janus-faced nature of pDC-derived type I IFNs.
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Affiliation(s)
- Dóra Bencze
- Department of Immunology, Faculty of Medicine, University of Debrecen, 1 Egyetem Square, H-4032 Debrecen, Hungary; (D.B.); (T.F.)
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 1 Egyetem Square, H-4032 Debrecen, Hungary
| | - Tünde Fekete
- Department of Immunology, Faculty of Medicine, University of Debrecen, 1 Egyetem Square, H-4032 Debrecen, Hungary; (D.B.); (T.F.)
| | - Kitti Pázmándi
- Department of Immunology, Faculty of Medicine, University of Debrecen, 1 Egyetem Square, H-4032 Debrecen, Hungary; (D.B.); (T.F.)
- Correspondence: ; Tel./Fax: +36-52-417-159
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29
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Acoba MG, Senoo N, Claypool SM. Phospholipid ebb and flow makes mitochondria go. J Cell Biol 2021; 219:151918. [PMID: 32614384 PMCID: PMC7401802 DOI: 10.1083/jcb.202003131] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/28/2020] [Accepted: 06/02/2020] [Indexed: 01/19/2023] Open
Abstract
Mitochondria, so much more than just being energy factories, also have the capacity to synthesize macromolecules including phospholipids, particularly cardiolipin (CL) and phosphatidylethanolamine (PE). Phospholipids are vital constituents of mitochondrial membranes, impacting the plethora of functions performed by this organelle. Hence, the orchestrated movement of phospholipids to and from the mitochondrion is essential for cellular integrity. In this review, we capture recent advances in the field of mitochondrial phospholipid biosynthesis and trafficking, highlighting the significance of interorganellar communication, intramitochondrial contact sites, and lipid transfer proteins in maintaining membrane homeostasis. We then discuss the physiological functions of CL and PE, specifically how they associate with protein complexes in mitochondrial membranes to support bioenergetics and maintain mitochondrial architecture.
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Affiliation(s)
- Michelle Grace Acoba
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Nanami Senoo
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Steven M Claypool
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
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30
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Flagging fusion: Phosphatidylserine signaling in cell-cell fusion. J Biol Chem 2021; 296:100411. [PMID: 33581114 PMCID: PMC8005811 DOI: 10.1016/j.jbc.2021.100411] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 02/06/2023] Open
Abstract
Formations of myofibers, osteoclasts, syncytiotrophoblasts, and fertilized zygotes share a common step, cell–cell fusion. Recent years have brought about considerable progress in identifying some of the proteins involved in these and other cell-fusion processes. However, even for the best-characterized cell fusions, we still do not know the mechanisms that regulate the timing of cell-fusion events. Are they fully controlled by the expression of fusogenic proteins or do they also depend on some triggering signal that activates these proteins? The latter scenario would be analogous to the mechanisms that control the timing of exocytosis initiated by Ca2+ influx and virus-cell fusion initiated by low pH- or receptor interaction. Diverse cell fusions are accompanied by the nonapoptotic exposure of phosphatidylserine at the surface of fusing cells. Here we review data on the dependence of membrane remodeling in cell fusion on phosphatidylserine and phosphatidylserine-recognizing proteins and discuss the hypothesis that cell surface phosphatidylserine serves as a conserved “fuse me” signal regulating the time and place of cell-fusion processes.
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31
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Mattenberger F, Latorre V, Tirosh O, Stern A, Geller R. Globally defining the effects of mutations in a picornavirus capsid. eLife 2021; 10:64256. [PMID: 33432927 PMCID: PMC7861617 DOI: 10.7554/elife.64256] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 01/11/2021] [Indexed: 02/07/2023] Open
Abstract
The capsids of non-enveloped viruses are highly multimeric and multifunctional protein assemblies that play key roles in viral biology and pathogenesis. Despite their importance, a comprehensive understanding of how mutations affect viral fitness across different structural and functional attributes of the capsid is lacking. To address this limitation, we globally define the effects of mutations across the capsid of a human picornavirus. Using this resource, we identify structural and sequence determinants that accurately predict mutational fitness effects, refine evolutionary analyses, and define the sequence specificity of key capsid-encoded motifs. Furthermore, capitalizing on the derived sequence requirements for capsid-encoded protease cleavage sites, we implement a bioinformatic approach for identifying novel host proteins targeted by viral proteases. Our findings represent the most comprehensive investigation of mutational fitness effects in a picornavirus capsid to date and illuminate important aspects of viral biology, evolution, and host interactions. A virus is made up of genetic material that is encased with a protective protein coat called the capsid. The capsid also helps the virus to infect host cells by binding to the host receptor proteins and releasing its genetic material. Inside the cell, the virus hitchhikes the infected cell’s machinery to grow or replicate its own genetic material. Viral capsids are the main target of the host’s defence system, and therefore, continuously change in an attempt to escape the immune system by introducing alterations (known as mutations) into the genes encoding viral capsid proteins. Mutations occur randomly, and so while some changes to the viral capsid might confer an advantage, others may have no effect at all, or even weaken the virus. To better understand the effect of capsid mutations on the virus’ ability to infect host cells, Mattenberger et al. studied the Coxsackievirus B3, which is linked to heart problems and acute heart failure in humans. The researchers analysed around 90% of possible amino acid mutations (over 14,800 mutations) and correlated each mutation to how it influenced the virus’ ability to replicate in human cells grown in the laboratory. Based on these results, Mattenberger et al. developed a computer model to predict how a particular mutation might affect the virus. The analysis also identified specific amino acid sequences of capsid proteins that are essential for certain tasks, such as building the capsid. It also included an analysis of sequences in the capsid that allow it to be recognized by another viral protein, which cuts the capsid proteins into the right size from a larger precursor. By looking for similar sequences in human genes, the researchers identified several ones that the virus may attack and inactivate to support its own replication. These findings may help identify potential drug targets to develop new antiviral therapies. For example, proteins of the capsid that are less likely to mutate will provide a better target as they lower the possibility of the virus to become resistant to the treatment. They also highlight new proteins in human cells that could potentially block the virus in cells.
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Affiliation(s)
- Florian Mattenberger
- Institute for Integrative Systems Biology, I2SysBio (Universitat de València-CSIC), Paterna, Spain
| | - Victor Latorre
- Institute for Integrative Systems Biology, I2SysBio (Universitat de València-CSIC), Paterna, Spain
| | - Omer Tirosh
- The Shmunis School of Biomedicine and Cancer Research, Tel-Aviv University, Tel-Aviv, Israel
| | - Adi Stern
- The Shmunis School of Biomedicine and Cancer Research, Tel-Aviv University, Tel-Aviv, Israel
| | - Ron Geller
- Institute for Integrative Systems Biology, I2SysBio (Universitat de València-CSIC), Paterna, Spain
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32
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Argañaraz GA, Palmeira JDF, Argañaraz ER. Phosphatidylserine inside out: a possible underlying mechanism in the inflammation and coagulation abnormalities of COVID-19. Cell Commun Signal 2020; 18:190. [PMID: 33357215 PMCID: PMC7765775 DOI: 10.1186/s12964-020-00687-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/23/2020] [Indexed: 12/22/2022] Open
Abstract
The rapid ability of SARS-CoV-2 to spread among humans, along with the clinical complications of coronavirus disease 2019-COVID-19, have represented a significant challenge to the health management systems worldwide. The acute inflammation and coagulation abnormalities appear as the main causes for thousands of deaths worldwide. The intense inflammatory response could be involved with the formation of thrombi. For instance, the presence of uncleaved large multimers of von Willebrand (vWF), due to low ADAMTS13 activity in plasma could be explained by the inhibitory action of pro-inflammatory molecules such as IL-1β and C reactive protein. In addition, the damage to endothelial cells after viral infection and/or activation of endothelium by pro-inflammatory cytokines, such as IL-1β, IL-6, IFN-γ, IL-8, and TNF-α induces platelets and monocyte aggregation in the vascular wall and expression of tissue factor (TF). The TF expression may culminate in the formation of thrombi, and activation of cascade by the extrinsic pathway by association with factor VII. In this scenario, the phosphatidylserine-PtdSer exposure on the outer leaflet of the cell membrane as consequence of viral infection emerges as another possible underlying mechanism to acute immune inflammatory response and activation of coagulation cascade. The PtdSer exposure may be an important mechanism related to ADAM17-mediated ACE2, TNF-α, EGFR and IL-6R shedding, and the activation of TF on the surface of infected endothelial cells. In this review, we address the underlying mechanisms involved in the pathophysiology of inflammation and coagulation abnormalities. Moreover, we introduce key biochemical and pathophysiological concepts that support the possible participation of PtdSer exposure on the outer side of the SARS-CoV-2 infected cells membrane, in the pathophysiology of COVID-19. Video Abstract.
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Affiliation(s)
- Gustavo A. Argañaraz
- Laboratory of Molecular Neurovirology, Faculty of Health Science, University of Brasília, Brasília, 70910-900 Brazil
| | - Julys da Fonseca Palmeira
- Laboratory of Molecular Neurovirology, Faculty of Health Science, University of Brasília, Brasília, 70910-900 Brazil
| | - Enrique R. Argañaraz
- Laboratory of Molecular Neurovirology, Faculty of Health Science, University of Brasília, Brasília, 70910-900 Brazil
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33
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Alshetaiwi H, Pervolarakis N, McIntyre LL, Ma D, Nguyen Q, Rath JA, Nee K, Hernandez G, Evans K, Torosian L, Silva A, Walsh C, Kessenbrock K. Defining the emergence of myeloid-derived suppressor cells in breast cancer using single-cell transcriptomics. Sci Immunol 2020; 5:5/44/eaay6017. [PMID: 32086381 PMCID: PMC7219211 DOI: 10.1126/sciimmunol.aay6017] [Citation(s) in RCA: 259] [Impact Index Per Article: 64.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 01/23/2020] [Indexed: 12/26/2022]
Abstract
Myeloid-derived suppressor cells (MDSCs) are innate immune cells that acquire the capacity to suppress adaptive immune responses during cancer. It remains elusive how MDSCs differ from their normal myeloid counterparts, which limits our ability to specifically detect and therapeutically target MDSCs during cancer. Here, we sought to determine the molecular features of breast cancer-associated MDSCs using the widely studied mouse model based on the mouse mammary tumor virus (MMTV) promoter-driven expression of the polyomavirus middle T oncoprotein (MMTV-PyMT). To identify MDSCs in an unbiased manner, we used single-cell RNA sequencing to compare MDSC-containing splenic myeloid cells from breast tumor-bearing mice with wild-type controls. Our computational analysis of 14,646 single-cell transcriptomes revealed that MDSCs emerge through an aberrant neutrophil maturation trajectory in the spleen that confers them an immunosuppressive cell state. We establish the MDSC-specific gene signature and identify CD84 as a surface marker for improved detection and enrichment of MDSCs in breast cancers.
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Affiliation(s)
- Hamad Alshetaiwi
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA.,Department of Pathology, University of Hail, Hail 2440, Saudi Arabia
| | - Nicholas Pervolarakis
- Center for Complex Biological Systems, University of California, Irvine, Irvine, CA 92697, USA
| | - Laura Lynn McIntyre
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Dennis Ma
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Quy Nguyen
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Jan Akara Rath
- Ludwig Institute for Cancer Research, University of Lausanne, Epalinges 1066, Switzerland
| | - Kevin Nee
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Grace Hernandez
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
| | - Katrina Evans
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
| | - Leona Torosian
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Anushka Silva
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Craig Walsh
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697, USA
| | - Kai Kessenbrock
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA.
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Doktorova M, Symons JL, Levental I. Structural and functional consequences of reversible lipid asymmetry in living membranes. Nat Chem Biol 2020; 16:1321-1330. [PMID: 33199908 PMCID: PMC7747298 DOI: 10.1038/s41589-020-00688-0] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 10/05/2020] [Indexed: 12/18/2022]
Abstract
Maintenance of lipid asymmetry across the two leaflets of the plasma membrane (PM) bilayer is a ubiquitous feature of eukaryotic cells. Loss of this asymmetry has been widely associated with cell death. However, increasing evidence points to the physiological importance of non-apoptotic, transient changes in PM asymmetry. Such transient scrambling events are associated with a range of biological functions, including intercellular communication and intracellular signaling. Thus, regulation of interleaflet lipid distribution in the PM is a broadly important but underappreciated cellular process with key physiological and structural consequences. Here, we compile the mounting evidence revealing multifaceted, functional roles of PM asymmetry and transient loss thereof. We discuss the consequences of reversible asymmetry on PM structure, biophysical properties and interleaflet coupling. We argue that despite widespread recognition of broad aspects of membrane asymmetry, its importance in cell biology demands more in-depth investigation of its features, regulation, and physiological and pathological implications.
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Affiliation(s)
| | - Jessica L Symons
- University of Texas Health Science Center at Houston, Houston, TX, USA
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Kimura AK, Kimura T. Phosphatidylserine biosynthesis pathways in lipid homeostasis: Toward resolution of the pending central issue for decades. FASEB J 2020; 35:e21177. [PMID: 33205488 DOI: 10.1096/fj.202001802r] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/17/2020] [Accepted: 10/26/2020] [Indexed: 12/28/2022]
Abstract
Enzymatic control of lipid homeostasis in the cell is a vital element in the complex organization of life. Phosphatidylserine (PS) is an essential anionic phospholipid of cell membranes, and conducts numerous roles for their structural and functional integrity. In mammalian cells, two distinct enzymes phosphatidylserine synthases-1 (PSS1) and -2 (PSS2) in the mitochondria-associated membrane (MAM) in the ER perform de novo synthesis of PS. It is based on base-exchange reactions of the preexisting dominant phospholipids phosphatidylcholine (PC) and phosphatidylethanolamine (PE). While PSS2 specifically catalyzes the reaction "PE → PS," whether or not PSS1 is responsible for the same reaction along with the reaction "PC → PS" remains unsettled despite its fundamental impact on the major stoichiometry. We propose here that a key but the only report that appeared to have put scientists on hold for decades in answering to this issue may be viewed consistently with other available research reports; PSS1 utilizes the two dominant phospholipid classes at a similar intrinsic rate. In this review, we discuss the issue in view of the current information for the enzyme machineries, membrane structure and dynamics, intracellular network of lipid transport, and PS synthesis in health and disease. Resolution of the pending issue is thus critical in advancing our understanding of roles of the essential anionic lipid in biology, health, and disease.
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Affiliation(s)
- Atsuko K Kimura
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Tomohiro Kimura
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
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Seki M, Arashiki N, Takakuwa Y, Nitta K, Nakamura F. Reduction in flippase activity contributes to surface presentation of phosphatidylserine in human senescent erythrocytes. J Cell Mol Med 2020; 24:13991-14000. [PMID: 33103382 PMCID: PMC7754070 DOI: 10.1111/jcmm.16010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 08/07/2020] [Accepted: 09/14/2020] [Indexed: 12/19/2022] Open
Abstract
Mature human erythrocytes circulate in blood for approximately 120 days, and senescent erythrocytes are removed by splenic macrophages. During this process, the cell membranes of senescent erythrocytes express phosphatidylserine, which is recognized as a signal for phagocytosis by macrophages. However, the mechanisms underlying phosphatidylserine exposure in senescent erythrocytes remain unclear. To clarify these mechanisms, we isolated senescent erythrocytes using density gradient centrifugation and applied fluorescence‐labelled lipids to investigate the flippase and scramblase activities. Senescent erythrocytes showed a decrease in flippase activity but not scramblase activity. Intracellular ATP and K+, the known influential factors on flippase activity, were altered in senescent erythrocytes. Furthermore, quantification by immunoblotting showed that the main flippase molecule in erythrocytes, ATP11C, was partially lost in the senescent cells. Collectively, these results suggest that multiple factors, including altered intracellular substances and reduced ATP11C levels, contribute to decreased flippase activity in senescent erythrocytes in turn to, present phosphatidylserine on their cell membrane. The present study may enable the identification of novel therapeutic approaches for anaemic states, such as those in inflammatory diseases, rheumatoid arthritis, or renal anaemia, resulting from the abnormally shortened lifespan of erythrocytes.
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Affiliation(s)
- Momoko Seki
- Department of Biochemistry, School of Medicine, Tokyo Women's Medical University, Tokyo, Japan
| | - Nobuto Arashiki
- Department of Biochemistry, School of Medicine, Tokyo Women's Medical University, Tokyo, Japan
| | - Yuichi Takakuwa
- Department of Biochemistry, School of Medicine, Tokyo Women's Medical University, Tokyo, Japan
| | - Kosaku Nitta
- Department of Nephrology, Tokyo Women's Medical University, Tokyo, Japan
| | - Fumio Nakamura
- Department of Biochemistry, School of Medicine, Tokyo Women's Medical University, Tokyo, Japan
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Borchert C, Herman A, Roth M, Brooks AC, Friedenberg SG. RNA sequencing of whole blood in dogs with primary immune-mediated hemolytic anemia (IMHA) reveals novel insights into disease pathogenesis. PLoS One 2020; 15:e0240975. [PMID: 33091028 PMCID: PMC7580939 DOI: 10.1371/journal.pone.0240975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/06/2020] [Indexed: 11/29/2022] Open
Abstract
Immune-mediated hemolytic anemia (IMHA) is a life-threatening autoimmune disorder characterized by a self-mediated attack on circulating red blood cells. The disease occurs naturally in both dogs and humans, but is significantly more prevalent in dogs. Because of its shared features across species, dogs offer a naturally occurring model for studying IMHA in people. In this study, we used RNA sequencing of whole blood from treatment-naïve dogs to study transcriptome-wide changes in gene expression in newly diagnosed animals compared to healthy controls. We found many overexpressed genes in pathways related to neutrophil function, coagulation, and hematopoiesis. In particular, the most highly overexpressed gene in cases was a phospholipase scramblase, which mediates the externalization of phosphatidylserine from the inner to the outer leaflet of cell membranes. This family of genes has been shown to be critically important for programmed cell death of erythrocytes as well as the initiation of the clotting cascade. Unexpectedly, we found marked underexpression of many genes related to lymphocyte function. We also identified groups of genes that are highly associated with the inflammatory response and red blood cell regeneration in affected dogs. We did not find any genes that distinguished dogs that lived vs. those that died at 30 days following diagnosis, nor did we find any relevant genomic signatures of microbial organisms in the blood of affected animals. Future studies are warranted to validate these findings and assess their implication in developing novel therapeutic approaches for dogs and humans with IMHA.
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Affiliation(s)
- Corie Borchert
- Department of Veterinary Clinical Sciences, University of Minnesota College of Veterinary Medicine, St. Paul, Minnesota, United States of America
| | - Adam Herman
- Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Megan Roth
- Department of Veterinary Clinical Sciences, University of Minnesota College of Veterinary Medicine, St. Paul, Minnesota, United States of America
| | - Aimee C. Brooks
- Department of Veterinary Clinical Sciences, Purdue University College of Veterinary Medicine, West Lafayette, Indiana, United States of America
| | - Steven G. Friedenberg
- Department of Veterinary Clinical Sciences, University of Minnesota College of Veterinary Medicine, St. Paul, Minnesota, United States of America
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Martos SN, Campbell MR, Lozoya OA, Wang X, Bennett BD, Thompson IJB, Wan M, Pittman GS, Bell DA. Single-cell analyses identify dysfunctional CD16 + CD8 T cells in smokers. CELL REPORTS MEDICINE 2020; 1. [PMID: 33163982 PMCID: PMC7644053 DOI: 10.1016/j.xcrm.2020.100054] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Tobacco smoke exposure contributes to the global burden of communicable and chronic diseases. To identify the immune cells affected by smoking, we use single-cell RNA sequencing on peripheral blood from smokers and nonsmokers. Transcriptomes reveal a subpopulation of FCGR3A (CD16)-expressing natural killer (NK)-like CD8 T lymphocytes that increase in smokers. Mass cytometry confirms elevated CD16+ CD8 T cells in smokers. Inferred as highly differentiated by pseudotime analysis, NK-like CD8 T cells express markers that are characteristic of effector memory re-expressing CD45RA T (TEMRA) cells. Indicative of immune aging, smokers’ CD8 T cells are biased toward differentiated cells, and smokers have fewer naive cells than nonsmokers. DNA methylation-based models show that smoking dose is associated with accelerated aging and decreased telomere length, a biomarker of T cell senescence. Immune aging accompanies T cell senescence, which can ultimately lead to impaired immune function. This suggests a role for smoking-induced, senescence-associated immune dysregulation in smoking-mediated pathologies. Smoking shifts the composition of CD8 T cells from naive to differentiated states NK-like CD16+ CD8 TEMRA cells are elevated in smokers and express GZMB and PRF1 DNA methylation links smoking dose with age acceleration and shortened telomeres CD8 T, CD4 T, NKT, NK, and monocytes express senescence-linked genes in smokers
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Affiliation(s)
- Suzanne N Martos
- Environmental Epigenomics and Disease Group, Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, 27709.,These authors contributed equally
| | - Michelle R Campbell
- Environmental Epigenomics and Disease Group, Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, 27709.,These authors contributed equally
| | - Oswaldo A Lozoya
- Environmental Epigenomics and Disease Group, Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, 27709
| | - Xuting Wang
- Environmental Epigenomics and Disease Group, Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, 27709
| | - Brian D Bennett
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, 27709
| | - Isabel J B Thompson
- Environmental Epigenomics and Disease Group, Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, 27709
| | - Ma Wan
- Environmental Epigenomics and Disease Group, Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, 27709
| | - Gary S Pittman
- Environmental Epigenomics and Disease Group, Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, 27709
| | - Douglas A Bell
- Environmental Epigenomics and Disease Group, Immunity, Inflammation, and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, 27709
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Tidemand FG, Østergaard H, Ploug M, Kragelund BB, Arleth L. Efficient refolding and reconstitution of tissue factor into nanodiscs facilitates structural investigation of a multicomponent system on a lipid bilayer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183214. [DOI: 10.1016/j.bbamem.2020.183214] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/31/2020] [Accepted: 02/05/2020] [Indexed: 01/20/2023]
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Sadjadi J, Strumwasser AM, Victorino GP. Endothelial cell dysfunction during anoxia-reoxygenation is associated with a decrease in adenosine triphosphate levels, rearrangement in lipid bilayer phosphatidylserine asymmetry, and an increase in endothelial cell permeability. J Trauma Acute Care Surg 2020; 87:1247-1252. [PMID: 31464867 DOI: 10.1097/ta.0000000000002489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Phosphatidylserine (PS) is normally confined in an energy-dependent manner to the inner leaflet of the lipid cell membrane. During cellular stress, PS is exteriorized to the outer layer, initiating a cascade of events. Because cellular stress is often accompanied by decreased energy levels and because maintaining PS asymmetry is an energy-dependent process, it would make sense that cellular stress associated with decreased energy levels is also associated with PS exteriorization that ultimately leads to endothelial cell dysfunction. Our hypothesis was that anoxia-reoxygenation (A-R) is associated with decreased adenosine triphosphate (ATP) levels, increased PS exteriorization on endothelial cell membranes, and increased endothelial cell membrane permeability. METHODS The effect on ATP levels during A-R was measured via colorimetric assay in cultured cells. To measure the effect of A-R on PS levels, cultured cells underwent A-R and exteriorized PS levels and also total cell PS were measured via biofluorescence assay. Finally, we measured endothelial cell monolayer permeability to albumin after A-R. RESULTS The ATP levels in cell culture decreased 27% from baseline after A-R (p < 0.02). There was over a twofold increase in exteriorized PS as compared with controls (p < 0.01). Interestingly, we found that during A-R, the total amount of cellular PS increased (p < 0.01). The finding that total PS changed twofold over normal cells suggested that not only is there a change in the distribution of PS across the cell membrane, but there may also be an increase in the amount of PS inside the cell. Finally, A-R increased endothelial cell monolayer permeability (p < 0.01). CONCLUSION We found that endothelial cell dysfunction during A-R is associated with decreased ATP levels, increased PS exteriorization, and increased in monolayer permeability. This supports the idea that PS exteriorization may a key event during clinical scenarios involving oxygen lack and may 1 day lead to novel therapies in these situations.
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Affiliation(s)
- Javid Sadjadi
- From the Department of Surgery (J.S., G.P.V.), UC San Francisco East Bay, Oakland; and Department of Surgery (A.M.S.), University of Southern California, Los Angeles, California
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Li J, Li Z, Zhao S, Song Y, Si L, Wang X. Identification key genes, key miRNAs and key transcription factors of lung adenocarcinoma. J Thorac Dis 2020; 12:1917-1933. [PMID: 32642095 PMCID: PMC7330310 DOI: 10.21037/jtd-19-4168] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Background Lung adenocarcinoma (LUAD) is one of the most common cancers worldwide. The etiology and pathophysiology of LUAD remain unclear. The aim of the present study was to identify the key genes, miRNAs and transcription factors (TFs) associated with the pathogenesis and prognosis of LUAD. Methods Three gene expression profiles (GSE43458, GSE32863, GSE74706) of LUAD were obtained from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified by GEO2R.The Gene Ontology (GO) terms, pathways, and protein-protein interactions (PPIs) of these DEGs were analyzed. Bases on DEGs, the miRNAs and TFs were predicted. Furthermore, TF-gene-miRNA co-expression network was constructed to identify key genes, miRNAs and TFs by bioinformatic methods. The expressions and prognostic values of key genes, miRNAs and TFs were carried out through The Cancer Genome Atlas (TCGA) database and Kaplan Meier-plotter (KM) online dataset. Results A total of 337 overlapped DEGs (75 upregulated and 262 downregulated) of LUAD were identified from the three GSE datasets. Moreover, 851 miRNAs and 29 TFs were identified to be associated with these DEGs. In total, 10 hub genes, 10 key miRNAs and 10 key TFs were located in the central hub of the TF-gene-miRNA co-expression network, and validated using The Cancer Genome Atlas (TCGA) database. Specifically, seven genes (PHACTR2, MSRB3, GHR, PLSCR4, EPB41L2, NPNT, FBXO32), two miRNAs (hsa-let-7e-5p, hsa-miR-17-5p) and four TFs (STAT6, E2F1, ETS1, JUN) were identified to be associated with prognosis of LUAD, which have significantly different expressions between LUAD and normal lung tissue. Additionally, the miRNA/gene co-expression analysis also revealed that hsa-miR-17-5p and PLSCR4 have a significant negative co-expression relationship (r=−0.33, P=1.67e-14) in LUAD. Conclusions Our study constructed a regulatory network of TF-gene-miRNA in LUAD, which may provide new insights about the interaction between genes, miRNAs and TFs in the pathogenesis of LUAD, and identify potential biomarkers or therapeutic targets for LUAD.
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Affiliation(s)
- Jinghang Li
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Zhi Li
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Sheng Zhao
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Yuanyuan Song
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Linjie Si
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Xiaowei Wang
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
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Li Y, Zhao L, Zhao P, Liu Z. Long non-coding RNA LINC00641 suppresses non-small-cell lung cancer by sponging miR-424-5p to upregulate PLSCR4. Cancer Biomark 2020; 26:79-91. [PMID: 31322545 DOI: 10.3233/cbm-190142] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Non-small cell lung cancer (NSCLC) , as the most prevalent type of lung carcinoma with high severity, is of urgent necessity to be investigated for novel therapeutic strategies. Long non-coding RNAs (lncRNAs) are notable for their participation in cancer regulation, and lncRNA long intergenic non-protein coding RNA 641 (LINC00641) has been found to have an inhibitory influence on bladder cancer, but its role in NSCLC has not yet been studied. In this research, we launched an investigation into the biological functions and the underlying molecular mechanisms of LINC00641 in NSCLC. At first, downregulation of LINC00641 was identified in NSCLC cells. Functionally, LINC00641 suppressed cell proliferation and induced cell apoptosis in NSCLC, indicating that LINC00641 exerted tumor-suppressive role in NSCLC. Through mechanism investigation, we determined that LINC00641 acted as a competing endogenous RNA (ceRNA) in NSCLC by sponging miR-424-5p to upregulate phospholipid scramblase (PLSCR4) expression. Further rescue assays indicated that miR-424-5p and PLSCR4 could reverse LINC00641-mediated cellular processes. Taken together, it is demonstrated in our study that LINC00641 can function as a tumor suppressor in NSCLC via a ceRNA network.
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Transient Receptor Potential Canonical 5-Scramblase Signaling Complex Mediates Neuronal Phosphatidylserine Externalization and Apoptosis. Cells 2020; 9:cells9030547. [PMID: 32110987 PMCID: PMC7140530 DOI: 10.3390/cells9030547] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/24/2020] [Accepted: 02/24/2020] [Indexed: 12/24/2022] Open
Abstract
Phospholipid scramblase 1 (PLSCR1), a lipid-binding and Ca2+-sensitive protein located on plasma membranes, is critically involved in phosphatidylserine (PS) externalization, an important process in cell apoptosis. Transient receptor potential canonical 5 (TRPC5), is a nonselective Ca2+ channel in neurons that interacts with many downstream molecules, participating in diverse physiological functions including temperature or mechanical sensation. The interaction between TRPC5 and PLSCR1 has never been reported. Here, we showed that PLSCR1 interacts with TRPC5 through their C-termini in HEK293 cells and mouse cortical neurons. Formation of TRPC5-PLSCR1 complex stimulates PS externalization and promotes cell apoptosis in HEK293 cells and mouse cerebral neurons. Furthermore, in vivo studies showed that PS externalization in cortical neurons induced by artificial cerebral ischemia-reperfusion was reduced in TRPC5 knockout mice compared to wild-type mice, and that the percentage of apoptotic neurons was also lower in TRPC5 knockout mice than in wild-type mice. Collectively, the present study suggested that TRPC5-PLSCR1 is a signaling complex mediating PS externalization and apoptosis in neurons and that TRPC5 plays a pathological role in cerebral-ischemia reperfusion injury.
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Reconstitution of Proteoliposomes for Phospholipid Scrambling and Nonselective Channel Assays. Methods Mol Biol 2020; 2127:207-225. [PMID: 32112325 DOI: 10.1007/978-1-0716-0373-4_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Phospholipid scramblases catalyze the rapid trans-bilayer movement of lipids down their concentration gradients. This process is essential for numerous cellular signaling functions including cell fusion, blood coagulation, and apoptosis. The importance of scramblases is highlighted by the number of human diseases caused by mutations in these proteins. Because of their indispensable function, it is essential to understand and characterize the molecular function of phospholipid scramblases. Powerful tools to measure lipid transport in cells are available. However, these approaches provide limited mechanistic insights into the molecular bases of scrambling. Here we describe in detail an in vitro phospholipid scramblase assay and the accompanying analysis which allows for determination of the macroscopic rate constants associated with phospholipid scrambling. Notably, members of the TMEM16 family of scramblases also function as nonselective ion channels. To better understand the physiological relevance of this channel function as well as its relationship to the scrambling activity of the TMEM16s we also describe in detail an in vitro flux assay to measure nonselective channel activity. Together, these two assays can be used to investigate the dual activities of the TMEM16 scramblases/nonselective channels.
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Siggel M, Bhaskara RM, Hummer G. Phospholipid Scramblases Remodel the Shape of Asymmetric Membranes. J Phys Chem Lett 2019; 10:6351-6354. [PMID: 31566982 DOI: 10.1021/acs.jpclett.9b02531] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The cell membrane and many organellar membranes are asymmetric and highly curved. In experiments, it is challenging to reconstitute and characterize membranes that differ in the lipid composition of their leaflets. Here we use molecular dynamics simulations to study the large-scale membrane shape changes associated with lipid shuttling between asymmetric leaflets. We exploit leaflet asymmetry to create a stable, near-spherical vesicle bud connected to a flat bilayer under periodic boundary conditions. Then we demonstrate how the lipid scramblase nhTMEM16 relaxes the lipid-number asymmetry. By mediating the flipping of lipids, this transmembrane protein dissipates the mechanochemical gradient between the leaflets and drives a large-scale membrane reorganization, converting the vesicle bud into a flat membrane. Our procedure to exploit bilayer asymmetry for simulations of highly curved membranes can be used to study the function of other lipid transporters and membrane-shaping proteins.
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Affiliation(s)
- Marc Siggel
- Department of Theoretical Biophysics , Max Planck Institute of Biophysics , Max-von-Laue Str. 3 , 60438 Frankfurt am Main , Germany
| | - Ramachandra M Bhaskara
- Department of Theoretical Biophysics , Max Planck Institute of Biophysics , Max-von-Laue Str. 3 , 60438 Frankfurt am Main , Germany
| | - Gerhard Hummer
- Department of Theoretical Biophysics , Max Planck Institute of Biophysics , Max-von-Laue Str. 3 , 60438 Frankfurt am Main , Germany
- Institute of Biophysics , Goethe University Frankfurt , 60438 Frankfurt am Main , Germany
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Pezzotti G. Silicon Nitride: A Bioceramic with a Gift. ACS APPLIED MATERIALS & INTERFACES 2019; 11:26619-26636. [PMID: 31251018 DOI: 10.1021/acsami.9b07997] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In the closing decades of the 20th century, silicon nitride (Si3N4) was extensively developed for high-temperature gas turbine applications. Technologists attempted to take advantage of its superior thermal and mechanical properties to improve engine reliability and fuel economy. Yet, this promise was never realized in spite of the worldwide research, which was conducted at that time. Notwithstanding this disappointment, its use in medical applications in the early 21st century has been an unexpected gift. While retaining all of its engineered mechanical properties, it is now recognized for its peculiar surface chemistry. When immersed in an aqueous environment, the slow elution of silicon and nitrogen from its surface enhances healing of soft and osseous tissue, inhibits bacterial proliferation, and eradicates viruses. These benefits permit it to be used in a wide array of different disciplines inside and outside of the human body including orthopedics, dentistry, virology, agronomy, and environmental remediation. Given the global public health threat posed by mutating viruses and bacteria, silicon nitride offers a valid and straightforward alternative approach to fighting these pathogens. However, there is a conundrum behind these recent discoveries: How can this unique bioceramic be both friendly to mammalian cells while concurrently lysing invasive pathogens? This unparalleled characteristic can be explained by the pH-dependent kinetics of two ammonia species-NH4+ and NH3-both of which are leached from the wet Si3N4 surface.
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Affiliation(s)
- Giuseppe Pezzotti
- Ceramic Physics Laboratory , Kyoto Institute of Technology , Sakyo-ku, Matsugasaki , Kyoto 606-8585 , Japan
- Department of Orthopedic Surgery , Tokyo Medical University , 6-7-1 Nishi-Shinjuku , Shinjuku-ku, Tokyo 160-0023 , Japan
- The Center for Advanced Medical Engineering and Informatics , Osaka University , 2-2 Yamadaoka , Suita 565-0854 , Osaka , Japan
- Department of Immunology, Graduate School of Medical Science , Kyoto Prefectural University of Medicine , Kamigyo-ku, 465 Kajii-cho , Kyoto 602-8566 , Japan
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An Electrophysiological Approach to Measure Changes in the Membrane Surface Potential in Real Time. Biophys J 2019; 118:813-825. [PMID: 31409481 PMCID: PMC7036697 DOI: 10.1016/j.bpj.2019.06.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/21/2019] [Accepted: 06/26/2019] [Indexed: 02/07/2023] Open
Abstract
Biological membranes carry fixed charges at their surfaces. These arise primarily from phospholipid headgroups. In addition, membrane proteins contribute to the surface potential with their charged residues. Membrane lipids are asymmetrically distributed. Because of this asymmetry, the net-negative charge at the inner leaflet exceeds that at the outer leaflet. Changes in surface potential are predicted to give rise to apparent changes in membrane capacitance. Here, we show that it is possible to detect changes in surface potential by an electrophysiological approach; the analysis of cellular currents relies on assuming that the electrical properties of a cell are faithfully described by a three-element circuit (i.e., the minimal equivalent circuit) comprised of two resistors and one capacitor. However, to account for changes in surface potential, it is necessary to add a battery to this circuit connected in series with the capacitor. This extended circuit model predicts that the current response to a square-wave voltage pulse harbors information, which allows for separating the changes in surface potential from a true capacitance change. We interrogated our model by investigating changes in the capacitance induced by ligand binding to the serotonin transporter and to the glycine transporters (GlyT1 and GlyT2). The experimental observations were consistent with the predictions of the extended circuit. We conclude that ligand-induced changes in surface potential (reflecting the binding event) and in true membrane capacitance (reflecting the concomitant conformational change) can be detected in real time even in instances in which they occur simultaneously.
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Ansari SA, Pendurthi UR, Rao LVM. Role of Cell Surface Lipids and Thiol-Disulphide Exchange Pathways in Regulating the Encryption and Decryption of Tissue Factor. Thromb Haemost 2019; 119:860-870. [PMID: 30861549 DOI: 10.1055/s-0039-1681102] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Tissue factor (TF), a transmembrane glycoprotein, is the cellular receptor of the coagulation factors VII (FVII) and VIIa (FVIIa). The formation of TF-FVIIa complex triggers the initiation of the blood coagulation pathway. TF plays an essential role in haemostasis, but an aberrant expression of TF activity contributes to thrombotic disorders. In health, TF pro-coagulant activity on cells is controlled tightly to allow sufficient coagulant activity to achieve haemostasis but not to cause thrombosis. It is achieved largely by selective localization of TF in the body and encryption of TF at the cell surface. A vast majority of TF on resting cells exists in an encrypted state with minimal pro-coagulant activity but becomes pro-thrombotic following cell injury or activation. At present, the mechanisms that are responsible for TF encryption and activation (decryption) are not entirely clear, but recent studies provide important mechanistic insights into these processes. To date, externalization of phosphatidylserine to the outer leaflet and thiol-disulphide exchange pathways that either turn on and off the allosteric disulphide bond in TF are shown to play a major role in regulating TF pro-coagulant activity on cell surfaces. Recent studies showed that sphingomyelin, a major phospholipid in the outer leaflet of plasma membrane, plays a critical role in the encryption of TF in resting cells. The present review provides an overview of recent literature on the above-described mechanisms of TF encryption and decryption with a particular emphasis on our recent findings.
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Affiliation(s)
- Shabbir A Ansari
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, Texas, United States
| | - Usha R Pendurthi
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, Texas, United States
| | - L Vijaya Mohan Rao
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, Texas, United States
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Proteomic analysis of neutrophils in ANCA-associated vasculitis reveals a dysregulation in proteinase 3-associated proteins such as annexin-A1 involved in apoptotic cell clearance. Kidney Int 2019; 96:397-408. [PMID: 31142442 DOI: 10.1016/j.kint.2019.02.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 01/22/2019] [Accepted: 02/14/2019] [Indexed: 02/06/2023]
Abstract
Granulomatosis with polyangiitis (GPA) is an autoimmune vasculitis associated with anti-neutrophil-cytoplasmic antibodies (ANCA) against proteinase 3 leading to kidney damage. Neutrophils from those patients have increased expression of membrane proteinase 3 during apoptosis. Here we examined whether neutrophils from patients with GPA have dysregulated protein expressions associated with apoptosis. A global proteomic analysis was performed comparing neutrophils from patients with GPA, with healthy individuals under basal conditions and during apoptosis. At disease onset, the cytosolic proteome of neutrophils of patients with GPA before treatment was significantly different from healthy controls, and this dysregulation was more pronounced following ex vivo apoptosis. Proteins involved in cell death/survival were altered in neutrophils of patients with GPA. Several proteins identified were PR3-binding partners involved in the clearance of apoptotic cells, namely calreticulin, annexin-A1 and phospholipid scramblase 1. These proteins form a platform at the membrane of apoptotic neutrophils in patients with GPA but not healthy individuals and this was associated with the clinical presentation of GPA. Thus, our study shows that neutrophils from patients with GPA have an intrinsic dysregulation in proteins involved in apoptotic cell clearance, which could contribute to the unabated inflammation and autoimmunity in GPA. Hence, harnessing these dysregulated pathways could lead to novel biomarkers and targeted therapeutic opportunities to treat kidney disease.
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Phosphatidylserine is a marker for axonal debris engulfment but its exposure can be decoupled from degeneration. Cell Death Dis 2018; 9:1116. [PMID: 30389906 PMCID: PMC6214901 DOI: 10.1038/s41419-018-1155-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/25/2018] [Accepted: 10/08/2018] [Indexed: 02/08/2023]
Abstract
Apoptotic cells expose Phosphatidylserine (PS), that serves as an “eat me” signal for engulfing cells. Previous studies have shown that PS also marks degenerating axonsduring developmental pruning or in response to insults (Wallerian degeneration), but the pathways that control PS exposure on degenerating axons are largely unknown. Here, we used a series of in vitro assays to systematically explore the regulation of PS exposure during axonal degeneration. Our results show that PS exposure is regulated by the upstream activators of axonal pruning and Wallerian degeneration. However, our investigation of signaling further downstream revealed divergence between axon degeneration and PS exposure. Importantly, elevation of the axonal energetic status hindered PS exposure, while inhibition of mitochondrial activity caused PS exposure, without degeneration. Overall, our results suggest that the levels of PS on the outer axonal membrane can be dissociated from the degeneration process and that the axonal energetic status plays a key role in the regulation of PS exposure.
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