1
|
Walid MKI, Rahman S, Smith EA. Reciprocal effect on lateral diffusion of receptor for advanced glycation endproducts and toll-like receptor 4 in the HEK293 cell membrane. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2024:10.1007/s00249-024-01717-9. [PMID: 39066956 DOI: 10.1007/s00249-024-01717-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/28/2024] [Accepted: 07/18/2024] [Indexed: 07/30/2024]
Abstract
Receptor for advanced glycation endproducts (RAGE) and toll-like receptor 4 (TLR4) are pattern-recognition receptors that bind to molecular patterns associated with pathogens, stress, and cellular damage. Diffusion plays an important role in receptor functionality in the cell membrane. However, there has been no prior investigation of the reciprocal effect of RAGE and TLR4 diffusion properties in the presence and absence of each receptor. This study reports how RAGE and TLR4 affect the mobility of each other in the human embryonic kidney (HEK) 293 cell membrane. Diffusion properties were measured using single-particle tracking (SPT) with quantum dots (QDs) that are selectively attached to RAGE or TLR4. The Brownian diffusion coefficients of RAGE and TLR4 are affected by the presence of the other receptor, leading to similar diffusion coefficients when both receptors coexist in the cell. When TLR4 is present, the average Brownian diffusion coefficient of RAGE increases by 40%, while the presence of RAGE decreases the average Brownian diffusion coefficient of TLR4 by 32%. Diffusion in confined membrane domains is not altered by the presence of the other receptor. The mobility of the cell membrane lipid remains constant whether one or both receptors are present. Overall, this work shows that the presence of each receptor can affect a subset of diffusion properties of the other receptor without affecting the mobility of the membrane.
Collapse
Affiliation(s)
| | - Sharifur Rahman
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA
| | - Emily A Smith
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA.
| |
Collapse
|
2
|
Aljarrah D, Chalour N, Zorgani A, Nissan T, Pranjol MZI. Exploring the gut microbiota and its potential as a biomarker in gliomas. Biomed Pharmacother 2024; 173:116420. [PMID: 38471271 DOI: 10.1016/j.biopha.2024.116420] [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: 11/27/2023] [Revised: 02/24/2024] [Accepted: 03/07/2024] [Indexed: 03/14/2024] Open
Abstract
Gut microbiome alterations are associated with various cancers including brain tumours such as glioma and glioblastoma. The gut communicates with the brain via a bidirectional pathway known as the gut-brain axis (GBA) which is essential for maintaining homeostasis. The gut microbiota produces many metabolites including short chain fatty acids (SCFAs) and essential amino acids such as glutamate, glutamine, arginine and tryptophan. Through the modulation of these metabolites the gut microbiome is able to regulate several functions of brain cells, immune cells and tumour cells including DNA methylation, mitochondrial function, the aryl hydrocarbon receptor (AhR), T-cell proliferation, autophagy and even apoptosis. Here, we summarise current findings on gut microbiome with respect to brain cancers, an area of research that is widely overlooked. Several studies investigated the relationship between gut microbiota and brain tumours. However, it remains unclear whether the gut microbiome variation is a cause or product of cancer. Subsequently, a biomarker panel was constructed for use as a predictive, prognostic and diagnostic tool with respect to multiple cancers including glioma and glioblastoma multiforme (GBM). This review further presents the intratumoural microbiome, a fascinating microenvironment within the tumour as a possible treatment target that can be manipulated to maximise effectiveness of treatment via personalised therapy. Studies utilising the microbiome as a biomarker and therapeutic strategy are necessary to accurately assess the effectiveness of the gut microbiome as a clinical tool with respect to brain cancers.
Collapse
Affiliation(s)
- Dana Aljarrah
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton, UK.
| | - Naima Chalour
- Cognitive and Behavioural Neuroscience laboratory, Houari Boumediene University of Science and Technology, Bab Ezzouar, Algiers, Algeria; Faculty of Biological Sciences, Houari Boumediene University of Science and Technology, Bab Ezzouar, Algiers, Algeria.
| | - Amine Zorgani
- The Microbiome Mavericks, 60 rue Christian Lacouture, Bron 69500, France.
| | - Tracy Nissan
- Department of Molecular Biosciences, the Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.
| | - Md Zahidul I Pranjol
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton, UK.
| |
Collapse
|
3
|
Hu A, Sun L, Lin H, Liao Y, Yang H, Mao Y. Harnessing innate immune pathways for therapeutic advancement in cancer. Signal Transduct Target Ther 2024; 9:68. [PMID: 38523155 PMCID: PMC10961329 DOI: 10.1038/s41392-024-01765-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 01/18/2024] [Accepted: 02/03/2024] [Indexed: 03/26/2024] Open
Abstract
The innate immune pathway is receiving increasing attention in cancer therapy. This pathway is ubiquitous across various cell types, not only in innate immune cells but also in adaptive immune cells, tumor cells, and stromal cells. Agonists targeting the innate immune pathway have shown profound changes in the tumor microenvironment (TME) and improved tumor prognosis in preclinical studies. However, to date, the clinical success of drugs targeting the innate immune pathway remains limited. Interestingly, recent studies have shown that activation of the innate immune pathway can paradoxically promote tumor progression. The uncertainty surrounding the therapeutic effectiveness of targeted drugs for the innate immune pathway is a critical issue that needs immediate investigation. In this review, we observe that the role of the innate immune pathway demonstrates heterogeneity, linked to the tumor development stage, pathway status, and specific cell types. We propose that within the TME, the innate immune pathway exhibits multidimensional diversity. This diversity is fundamentally rooted in cellular heterogeneity and is manifested as a variety of signaling networks. The pro-tumor effect of innate immune pathway activation essentially reflects the suppression of classical pathways and the activation of potential pro-tumor alternative pathways. Refining our understanding of the tumor's innate immune pathway network and employing appropriate targeting strategies can enhance our ability to harness the anti-tumor potential of the innate immune pathway and ultimately bridge the gap from preclinical to clinical application.
Collapse
Affiliation(s)
- Ankang Hu
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, P.R. China
- Institute for Translational Brain Research, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- National Center for Neurological Disorders, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration, Shanghai Clinical Medical Center of Neurosurgery, Neurosurgical Institute of Fudan University, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, P.R. China
| | - Li Sun
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, P.R. China
- National Center for Neurological Disorders, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration, Shanghai Clinical Medical Center of Neurosurgery, Neurosurgical Institute of Fudan University, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, P.R. China
| | - Hao Lin
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, P.R. China
- National Center for Neurological Disorders, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration, Shanghai Clinical Medical Center of Neurosurgery, Neurosurgical Institute of Fudan University, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, P.R. China
| | - Yuheng Liao
- Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), and Key Laboratory of Metabolism and Molecular Medicine (Ministry of Education), and Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, P.R. China
| | - Hui Yang
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, P.R. China.
- Institute for Translational Brain Research, Shanghai Medical College, Fudan University, Shanghai, P.R. China.
- National Center for Neurological Disorders, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China.
- Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration, Shanghai Clinical Medical Center of Neurosurgery, Neurosurgical Institute of Fudan University, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China.
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, P.R. China.
| | - Ying Mao
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, P.R. China.
- National Center for Neurological Disorders, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China.
- Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration, Shanghai Clinical Medical Center of Neurosurgery, Neurosurgical Institute of Fudan University, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China.
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, P.R. China.
| |
Collapse
|
4
|
Hu A, Sun L, Lin H, Liao Y, Yang H, Mao Y. Harnessing the innate immune system by revolutionizing macrophage-mediated cancer immunotherapy. J Biosci 2024; 49:63. [PMID: 38864238 PMCID: PMC10961329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 01/18/2024] [Accepted: 02/03/2024] [Indexed: 06/13/2024]
Abstract
Immunotherapy is a promising and safer alternative to conventional cancer therapies. It involves adaptive T-cell therapy, cancer vaccines, monoclonal antibodies, immune checkpoint blockade (ICB), and chimeric antigen receptor (CAR) based therapies. However, most of these modalities encounter restrictions in solid tumours owing to a dense, highly hypoxic and immune-suppressive microenvironment as well as the heterogeneity of tumour antigens. The elevated intra-tumoural pressure and mutational rates within fastgrowing solid tumours present challenges in efficient drug targeting and delivery. The tumour microenvironment is a dynamic niche infiltrated by a variety of immune cells, most of which are macrophages. Since they form a part of the innate immune system, targeting macrophages has become a plausible immunotherapeutic approach. In this review, we discuss several versatile approaches (both at pre-clinical and clinical stages) such as the direct killing of tumour-associated macrophages, reprogramming pro-tumour macrophages to anti-tumour phenotypes, inhibition of macrophage recruitment into the tumour microenvironment, novel CAR macrophages, and genetically engineered macrophages that have been devised thus far. These strategies comprise a strong and adaptable macrophage-toolkit in the ongoing fight against cancer and by understanding their significance, we may unlock the full potential of these immune cells in cancer therapy.
Collapse
Affiliation(s)
- Ankang Hu
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, P.R. China
- Institute for Translational Brain Research, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- National Center for Neurological Disorders, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration, Shanghai Clinical Medical Center of Neurosurgery, Neurosurgical Institute of Fudan University, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, P.R. China
| | - Li Sun
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, P.R. China
- National Center for Neurological Disorders, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration, Shanghai Clinical Medical Center of Neurosurgery, Neurosurgical Institute of Fudan University, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, P.R. China
| | - Hao Lin
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, P.R. China
- National Center for Neurological Disorders, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration, Shanghai Clinical Medical Center of Neurosurgery, Neurosurgical Institute of Fudan University, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, P.R. China
| | - Yuheng Liao
- Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), and Key Laboratory of Metabolism and Molecular Medicine (Ministry of Education), and Molecular and Cell Biology Lab, Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, P.R. China
| | - Hui Yang
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, P.R. China
- Institute for Translational Brain Research, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- National Center for Neurological Disorders, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration, Shanghai Clinical Medical Center of Neurosurgery, Neurosurgical Institute of Fudan University, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, P.R. China
| | - Ying Mao
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, P.R. China
- National Center for Neurological Disorders, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration, Shanghai Clinical Medical Center of Neurosurgery, Neurosurgical Institute of Fudan University, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, P.R. China
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, P.R. China
| |
Collapse
|
5
|
Oseni SO, Naar C, Pavlović M, Asghar W, Hartmann JX, Fields GB, Esiobu N, Kumi-Diaka J. The Molecular Basis and Clinical Consequences of Chronic Inflammation in Prostatic Diseases: Prostatitis, Benign Prostatic Hyperplasia, and Prostate Cancer. Cancers (Basel) 2023; 15:3110. [PMID: 37370720 DOI: 10.3390/cancers15123110] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 05/23/2023] [Accepted: 05/31/2023] [Indexed: 06/29/2023] Open
Abstract
Chronic inflammation is now recognized as one of the major risk factors and molecular hallmarks of chronic prostatitis, benign prostatic hyperplasia (BPH), and prostate tumorigenesis. However, the molecular mechanisms by which chronic inflammation signaling contributes to the pathogenesis of these prostate diseases are poorly understood. Previous efforts to therapeutically target the upstream (e.g., TLRs and IL1-Rs) and downstream (e.g., NF-κB subunits and cytokines) inflammatory signaling molecules in people with these conditions have been clinically ambiguous and unsatisfactory, hence fostering the recent paradigm shift towards unraveling and understanding the functional roles and clinical significance of the novel and relatively underexplored inflammatory molecules and pathways that could become potential therapeutic targets in managing prostatic diseases. In this review article, we exclusively discuss the causal and molecular drivers of prostatitis, BPH, and prostate tumorigenesis, as well as the potential impacts of microbiome dysbiosis and chronic inflammation in promoting prostate pathologies. We specifically focus on the importance of some of the underexplored druggable inflammatory molecules, by discussing how their aberrant signaling could promote prostate cancer (PCa) stemness, neuroendocrine differentiation, castration resistance, metabolic reprogramming, and immunosuppression. The potential contribution of the IL1R-TLR-IRAK-NF-κBs signaling molecules and NLR/inflammasomes in prostate pathologies, as well as the prospective benefits of selectively targeting the midstream molecules in the various inflammatory cascades, are also discussed. Though this review concentrates more on PCa, we envision that the information could be applied to other prostate diseases. In conclusion, we have underlined the molecular mechanisms and signaling pathways that may need to be targeted and/or further investigated to better understand the association between chronic inflammation and prostate diseases.
Collapse
Affiliation(s)
- Saheed Oluwasina Oseni
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
- H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA
| | - Corey Naar
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Mirjana Pavlović
- Department of Computer and Electrical Engineering, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Waseem Asghar
- Department of Computer and Electrical Engineering, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - James X Hartmann
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Gregg B Fields
- Department of Chemistry & Biochemistry, and I-HEALTH, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Nwadiuto Esiobu
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - James Kumi-Diaka
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
| |
Collapse
|
6
|
Heine H, Zamyatina A. Therapeutic Targeting of TLR4 for Inflammation, Infection, and Cancer: A Perspective for Disaccharide Lipid A Mimetics. Pharmaceuticals (Basel) 2022; 16:23. [PMID: 36678520 PMCID: PMC9864529 DOI: 10.3390/ph16010023] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 12/28/2022] Open
Abstract
The Toll-like receptor 4 (TLR4) signaling pathway plays a central role in the prompt defense against infectious challenge and provides immediate response to Gram-negative bacterial infection. The TLR4/MD-2 complex can sense and respond to various pathogen-associated molecular patterns (PAMPs) with bacterial lipopolysaccharide (LPS) being the most potent and the most frequently occurring activator of the TLR4-mediated inflammation. TLR4 is believed to be both a friend and foe since improperly regulated TLR4 signaling can result in the overactivation of immune responses leading to sepsis, acute lung injury, or pathologic chronic inflammation involved in cancer and autoimmune disease. TLR4 is also considered a legitimate target for vaccine adjuvant development since its activation can boost the adaptive immune responses. The dual action of the TLR4 complex justifies the efforts in the development of both TLR4 antagonists as antisepsis drug candidates or remedies for chronic inflammatory diseases and TLR4 agonists as vaccine adjuvants or immunotherapeutics. In this review, we provide a brief overview of the biochemical evidences for possible pharmacologic applications of TLR4 ligands as therapeutics and report our systematic studies on the design, synthesis, and immunobiological evaluation of carbohydrate-based TLR4 antagonists with nanomolar affinity for MD-2 as well as disaccharide-based TLR4 agonists with picomolar affinity for the TLR4/MD-2 complex.
Collapse
Affiliation(s)
- Holger Heine
- Research Group Innate Immunity, Research Center Borstel—Leibniz Lung Center, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Parkallee 22, 23845 Borstel, Germany
| | - Alla Zamyatina
- Department of Chemistry, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
| |
Collapse
|
7
|
Stephens M. The emerging potential of Aptamers as therapeutic agents in infection and inflammation. Pharmacol Ther 2022; 238:108173. [DOI: 10.1016/j.pharmthera.2022.108173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 03/10/2022] [Accepted: 03/15/2022] [Indexed: 10/18/2022]
|
8
|
TLR4 biased small molecule modulators. Pharmacol Ther 2021; 228:107918. [PMID: 34171331 DOI: 10.1016/j.pharmthera.2021.107918] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/31/2021] [Accepted: 06/01/2021] [Indexed: 12/12/2022]
Abstract
Biased pharmacological modulators provide potential therapeutic benefits, including greater pharmacodynamic specificity, increased efficiency and reduced adverse effects. Therefore, the identification of such modulators as drug candidates is highly desirable. Currently, attention was mainly paid to biased signaling modulators targeting G protein-coupled receptors (GPCRs). The biased signaling modulation of non-GPCR receptors has yet to be exploited. Toll-like receptor 4 (TLR4) is one such non-GPCR receptor, which involves MyD88-dependent and TRIF-dependent signaling pathways. Moreover, the dysregulation of TLR4 contributes to numerous diseases, which highlights the importance of biased modulator development targeting TLR4. In this review, we aim to provide an overview of the recent progress in the discovery of biased modulators of TLR4. The challenges and methods for the discovery of TLR4 biased modulators are also outlined. Small molecules biasedly modulating the TLR4 signaling axis not only provide probes to fine-tune receptor conformation and signaling but also provide an opportunity to identify promising drug candidates. The discovery of biased modulators of TLR4 would provide insight for the future development of biased modulators for other non-GPCR receptors.
Collapse
|
9
|
Li M, Yu Y. Innate immune receptor clustering and its role in immune regulation. J Cell Sci 2021; 134:134/4/jcs249318. [PMID: 33597156 DOI: 10.1242/jcs.249318] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The discovery of receptor clustering in the activation of adaptive immune cells has revolutionized our understanding of the physical basis of immune signal transduction. In contrast to the extensive studies of adaptive immune cells, particularly T cells, there is a lesser, but emerging, recognition that the formation of receptor clusters is also a key regulatory mechanism in host-pathogen interactions. Many kinds of innate immune receptors have been found to assemble into nano- or micro-sized domains on the surfaces of cells. The clusters formed between diverse categories of innate immune receptors function as a multi-component apparatus for pathogen detection and immune response regulation. Here, we highlight these pioneering efforts and the outstanding questions that remain to be answered regarding this largely under-explored research topic. We provide a critical analysis of the current literature on the clustering of innate immune receptors. Our emphasis is on studies that draw connections between the phenomenon of receptor clustering and its functional role in innate immune regulation.
Collapse
Affiliation(s)
- Miao Li
- Department of Chemistry, Indiana University, Bloomington, IN 47401, USA
| | - Yan Yu
- Department of Chemistry, Indiana University, Bloomington, IN 47401, USA
| |
Collapse
|
10
|
Stephens M, Liao S, von der Weid PY. Ultra-purification of Lipopolysaccharides reveals species-specific signalling bias of TLR4: importance in macrophage function. Sci Rep 2021; 11:1335. [PMID: 33446670 PMCID: PMC7809447 DOI: 10.1038/s41598-020-79145-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 11/30/2020] [Indexed: 01/03/2023] Open
Abstract
TLR4 location, and bacterial species-derived lipopolysaccharides, play a significant role in the downstream activation of transcription factors, accessory molecules, and products. Here, this is demonstrated through the use of classically-activated and alternatively-activated macrophages. We show that, when polarized, human macrophages differentially express and localize TLR4, resulting in biased recognition and subsequent signalling of LPS derived from Pseudomonas aeruginosa, Escherichia coli, and Salmonella enterica. Analysis of activation demonstrated that in classically activated macrophages, P. aeruginosa signals from the plasma membrane via TLR4 to p65 dependent on TAK1 and TBK1 signalling. E. coli signals dependent or independent of the endosome, utilizing both TAK1- and TBK1-signalling to induce P65 and IRF3 inducible genes and cytokines. S. enterica however, only induces P65 and IRF3 phosphorylation through signalling via the endosome. This finding outlines clear signalling mechanisms by which innate immune cells, such as macrophages, can distinguish between bacterial species and initiate specialized responses through TLR4.
Collapse
Affiliation(s)
- Matthew Stephens
- Department of Physiology and Pharmacology, Inflammation Research Network, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Shan Liao
- Department of Microbiology, Immunology & Infectious Disease, Inflammation Research Network, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Pierre-Yves von der Weid
- Department of Physiology and Pharmacology, Inflammation Research Network, Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Alberta, Canada.
| |
Collapse
|
11
|
The Inhibition of miR-873 Provides Therapeutic Benefit in a Lipopolysaccharide-Induced Neuroinflammatory Model of Parkinson's Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:8735249. [PMID: 32724496 PMCID: PMC7381950 DOI: 10.1155/2020/8735249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/05/2020] [Accepted: 06/11/2020] [Indexed: 11/18/2022]
Abstract
Background and Purpose. Alterations in cholesterol homeostasis have been reported in cell and animal models of Parkinson's disease (PD), although there are inconsistent data about the association between serum cholesterol levels and risk of PD. Here, we investigated the effects of miR-873 on lysosomal cholesterol homeostasis and progressive dopaminergic neuron damage in a lipopolysaccharide-(LPS) induced model of PD. Experimental Approach. To evaluate the therapeutic benefit of the miR-873 sponge, rats were injected with a LV-miR-873 sponge or the control vector 3 days before the right-unilateral injection of LPS into the substantia nigra (SN) pars compacta, or 8 and 16 days after LPS injection. Normal SH-SY5Y cells or SH-SY5Y cells overexpressing α-synuclein were used to evaluate the distribution of α-synuclein and cholesterol in lysosomes and to assess the autophagic flux after miR-873 transfection or ABCA1 silencing. The inhibition of miR-873 significantly ameliorated the LPS-induced accumulation of α-synuclein and loss of dopaminergic neurons in the SN at the early stage. miR-873 mediated the inhibition of ABCA1 by LPS. miR-873 transfection or ABCA1 silencing increased the lysosomal cholesterol and α-synuclein levels, and decreased the autophagic flux. The knockdown of ABCA1 or A20, which are the downstream target genes of miR-873, exacerbated the damage to LPS-induced dopaminergic neurons. Conclusion and Implications. The results suggest that the inhibition of miR-873 may play a dual protective role by improving intracellular cholesterol homeostasis and neuroinflammation in PD. The therapeutic effects of the miR-873 sponge in PD may be due to the upregulation of ABCA1 and A20.
Collapse
|
12
|
Ziegler K, Kunert AT, Reinmuth-Selzle K, Leifke AL, Widera D, Weller MG, Schuppan D, Fröhlich-Nowoisky J, Lucas K, Pöschl U. Chemical modification of pro-inflammatory proteins by peroxynitrite increases activation of TLR4 and NF-κB: Implications for the health effects of air pollution and oxidative stress. Redox Biol 2020; 37:101581. [PMID: 32739154 PMCID: PMC7767743 DOI: 10.1016/j.redox.2020.101581] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/10/2020] [Accepted: 05/11/2020] [Indexed: 01/05/2023] Open
Abstract
Environmental pollutants like fine particulate matter can cause adverse health effects through oxidative stress and inflammation. Reactive oxygen and nitrogen species (ROS/RNS) such as peroxynitrite can chemically modify proteins, but the effects of such modifications on the immune system and human health are not well understood. In the course of inflammatory processes, the Toll-like receptor 4 (TLR4) can sense damage-associated molecular patterns (DAMPs). Here, we investigate how the TLR4 response and pro-inflammatory potential of the proteinous DAMPs α-Synuclein (α-Syn), heat shock protein 60 (HSP60), and high-mobility-group box 1 protein (HMGB1), which are relevant in neurodegenerative and cardiovascular diseases, changes upon chemical modification with peroxynitrite. For the peroxynitrite-modified proteins, we found a strongly enhanced activation of TLR4 and the pro-inflammatory transcription factor NF-κB in stable reporter cell lines as well as increased mRNA expression and secretion of the pro-inflammatory cytokines TNF-α, IL-1β, and IL-8 in human monocytes (THP-1). This enhanced activation of innate immunity via TLR4 is mediated by covalent chemical modifications of the studied DAMPs. Our results show that proteinous DAMPs modified by peroxynitrite more potently amplify inflammation via TLR4 activation than the native DAMPs, and provide first evidence that such modifications can directly enhance innate immune responses via a defined receptor. These findings suggest that environmental pollutants and related ROS/RNS may play a role in promoting acute and chronic inflammatory disorders by structurally modifying the body's own DAMPs. This may have important consequences for chronic neurodegenerative, cardiovascular or gastrointestinal diseases that are prevalent in modern societies, and calls for action, to improve air quality and climate in the Anthropocene. Pollutants and oxidative stress can cause protein nitration and oligomerization. Peroxynitrite amplifies inflammatory potential of disease-related proteins in vitro. Chemical modification of damage-associated molecular patterns (DAMPs). Positive feedback of modified DAMPs via pattern recognition receptor (TLR4). Air pollution may promote inflammatory disorders in the Anthropocene.
Collapse
Affiliation(s)
- Kira Ziegler
- Max Planck Institute for Chemistry, Multiphase Chemistry Department, 55128, Mainz, Germany
| | - Anna T Kunert
- Max Planck Institute for Chemistry, Multiphase Chemistry Department, 55128, Mainz, Germany
| | | | - Anna Lena Leifke
- Max Planck Institute for Chemistry, Multiphase Chemistry Department, 55128, Mainz, Germany
| | - Darius Widera
- Stem Cell Biology and Regenerative Medicine Group, School of Pharmacy, University of Reading, RG6 6AP, Reading, UK
| | - Michael G Weller
- Federal Institute for Materials Research and Testing (BAM), Berlin, Germany
| | - Detlef Schuppan
- Institute of Translational Immunology, University Medical Center of the Johannes Gutenberg University, 55131, Mainz, Germany; Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, MA, 02215, USA
| | | | - Kurt Lucas
- Max Planck Institute for Chemistry, Multiphase Chemistry Department, 55128, Mainz, Germany.
| | - Ulrich Pöschl
- Max Planck Institute for Chemistry, Multiphase Chemistry Department, 55128, Mainz, Germany.
| |
Collapse
|
13
|
Litak J, Grochowski C, Litak J, Osuchowska I, Gosik K, Radzikowska E, Kamieniak P, Rolinski J. TLR-4 Signaling vs. Immune Checkpoints, miRNAs Molecules, Cancer Stem Cells, and Wingless-Signaling Interplay in Glioblastoma Multiforme-Future Perspectives. Int J Mol Sci 2020; 21:ijms21093114. [PMID: 32354122 PMCID: PMC7247696 DOI: 10.3390/ijms21093114] [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: 03/20/2020] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 02/06/2023] Open
Abstract
Toll-like-receptor (TLR) family members were detected in the central nervous system (CNS). TLR occurrence was noticed and widely described in glioblastomamultiforme (GBM) cells. After ligand attachment, TLR-4 reorients domains and dimerizes, activates an intracellular cascade, and promotes further cytoplasmatic signaling. There is evidence pointing at a strong relation between TLR-4 signaling and micro ribonucleic acid (miRNA) expression. The TLR-4/miRNA interplay changes typical signaling and encourages them to be a target for modern immunotherapy. TLR-4 agonists initiate signaling and promote programmed death ligand-1 (PD-1L) expression. Most of those molecules are intensively expressed in the GBM microenvironment, resulting in the autocrine induction of regional immunosuppression. Another potential target for immunotreatment is connected with limited TLR-4 signaling that promotes Wnt/DKK-3/claudine-5 signaling, resulting in a limitation of GBM invasiveness. Interestingly, TLR-4 expression results in bordering proliferative trends in cancer stem cells (CSC) and GBM. All of these potential targets could bring new hope for patients suffering from this incurable disease. Clinical trials concerning TLR-4 signaling inhibition/promotion in many cancers are recruiting patients. There is still a lot to do in the field of GBM immunotherapy.
Collapse
Affiliation(s)
- Jakub Litak
- Department of Neurosurgery and Pediatric Neurosurgery, Medical University of Lublin, 20-954 Lublin, Poland
- Department of Immunology, Medical University of Lublin, 20-093 Lublin, Poland
| | - Cezary Grochowski
- Department of Anatomy, Medical University of Lublin, 20-090 Lublin, Poland
- Laboratory of Virtual Man, Department of Anatomy, Medical University of Lublin, 20-090 Lublin, Poland
- Correspondence:
| | - Joanna Litak
- St. John‘s Cancer Center in Lublin, 20-090 Lublin, Poland
| | - Ida Osuchowska
- Department of Anatomy, Medical University of Lublin, 20-090 Lublin, Poland
| | - Krzysztof Gosik
- Department of Immunology, Medical University of Lublin, 20-093 Lublin, Poland
| | | | - Piotr Kamieniak
- Department of Immunology, Medical University of Lublin, 20-093 Lublin, Poland
| | - Jacek Rolinski
- Department of Immunology, Medical University of Lublin, 20-093 Lublin, Poland
| |
Collapse
|
14
|
Vallance TM, Ravishankar D, Albadawi DAI, Layfield H, Sheard J, Vaiyapuri R, Dash P, Patel K, Widera D, Vaiyapuri S. Effect of ultrapure lipopolysaccharides derived from diverse bacterial species on the modulation of platelet activation. Sci Rep 2019; 9:18258. [PMID: 31796818 PMCID: PMC6890654 DOI: 10.1038/s41598-019-54617-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 11/18/2019] [Indexed: 11/09/2022] Open
Abstract
Platelets are small circulating blood cells that play essential roles in the maintenance of haemostasis via blood clotting. However, they also play critical roles in the regulation of innate immune responses. Inflammatory receptors, specifically Toll-like receptor (TLR)-4, have been reported to modify platelet reactivity. A plethora of studies have reported controversial functions of TLR4 in the modulation of platelet function using various chemotypes and preparations of its ligand, lipopolysaccharide (LPS). The method of preparation of LPS may explain these discrepancies however this is not fully understood. Hence, to determine the impact of LPS on platelet activation, we used ultrapure preparations of LPS from Escherichia coli (LPSEC), Salmonella minnesota (LPSSM), and Rhodobacter sphaeroides (LPSRS) and examined their actions under diverse experimental conditions in human platelets. LPSEC did not affect platelet activation markers such as inside-out signalling to integrin αIIbβ3 or P-selectin exposure upon agonist-induced activation in platelet-rich plasma or whole blood whereas LPSSM and LPSRS inhibited platelet activation under specific conditions at supraphysiological concentrations. Overall, our data demonstrate that platelet activation is not largely influenced by any of the ultrapure LPS chemotypes used in this study on their own except under certain conditions.
Collapse
Affiliation(s)
- Thomas M Vallance
- School of Pharmacy, University of Reading, Reading, RG6 6UB, United Kingdom
| | | | - Dina A I Albadawi
- School of Pharmacy, University of Reading, Reading, RG6 6UB, United Kingdom
| | - Harry Layfield
- School of Pharmacy, University of Reading, Reading, RG6 6UB, United Kingdom
| | - Jonathan Sheard
- Stem Cell Biology and Regenerative Medicine Group, School of Pharmacy, University of Reading, Reading, RG6 6UB, United Kingdom.,Sheard BioTech Ltd, 20-22, Wenlock Road, London, N1 7GU, United Kingdom
| | | | - Philip Dash
- School of Biological Sciences, University of Reading, Reading, RG6 6UB, United Kingdom
| | - Ketan Patel
- School of Biological Sciences, University of Reading, Reading, RG6 6UB, United Kingdom
| | - Darius Widera
- Stem Cell Biology and Regenerative Medicine Group, School of Pharmacy, University of Reading, Reading, RG6 6UB, United Kingdom
| | - Sakthivel Vaiyapuri
- School of Pharmacy, University of Reading, Reading, RG6 6UB, United Kingdom.
| |
Collapse
|
15
|
Wang X, Northcutt AL, Cochran TA, Zhang X, Fabisiak TJ, Haas ME, Amat J, Li H, Rice KC, Maier SF, Bachtell RK, Hutchinson MR, Watkins LR. Methamphetamine Activates Toll-Like Receptor 4 to Induce Central Immune Signaling within the Ventral Tegmental Area and Contributes to Extracellular Dopamine Increase in the Nucleus Accumbens Shell. ACS Chem Neurosci 2019; 10:3622-3634. [PMID: 31282647 DOI: 10.1021/acschemneuro.9b00225] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Methamphetamine (METH) is a globally abused, highly addictive stimulant. While investigations of the rewarding and motivational effects of METH have focused on neuronal actions, increasing evidence suggests that METH can also target microglia, the innate immune cells of the central nervous system, causing release of proinflammatory mediators and therefore amplifying the reward changes in the neuronal activity induced by METH. However, how METH induces neuroinflammatory responses within the central nervous system (CNS) is unknown. Herein, we provide direct evidence that METH creates neuroinflammation, at least in part, via the activation of the innate immune Toll-like receptor 4 (TLR4). Biophysical studies revealed that METH bound to MD-2, the key coreceptor of TLR4. Molecular dynamics simulations showed METH binding stabilized the active heterotetramer (TLR4/MD-2)2 conformation. Classic TLR4 antagonists LPS-RS and TAK-242 attenuated METH induced NF-κB activation of microglia, whereas added MD-2 protein boosted METH-induced NF-κB activation. Systemically administered METH (1 mg/kg) was found to specifically up-regulate expression of both CD11b (microglial activation marker) and the proinflammatory cytokine interleukin 6 (IL-6) mRNAs in the ventral tegmental area (VTA), but not in either the nucleus accumbens shell (NAc) or prefrontal cortex (PFC). Systemic administration of a nonopioid, blood-brain barrier permeable TLR4 antagonist (+)-naloxone inhibited METH-induced activation of microglia and IL-6 mRNA overexpression in VTA. METH was found to increase conditioned place preference (CPP) as well as extracellular dopamine concentrations in the NAc, with both effects suppressed by the nonopioid TLR4 antagonist (+)-naloxone. Furthermore, intra-VTA injection of LPS-RS or IL-6 neutralizing antibody suppressed METH-induced elevation of extracellular NAc dopamine. Taken together, this series of studies demonstrate that METH-induced neuroinflammation is, at least in part, mediated by TLR4-IL6 signaling within the VTA, which has the downstream effect of elevating dopamine in the NAc shell. These results provide a novel understanding of the neurobiological mechanisms underlying acute METH reward that includes a critical role for central immune signaling and offers a new target for medication development for treating drug abuse.
Collapse
Affiliation(s)
- Xiaohui Wang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- Department of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Alexis L. Northcutt
- Department of Psychology and Neuroscience and the Center for Neuroscience, University of Colorado at Boulder, Boulder, Colorado 80309, United States
| | - Thomas A. Cochran
- Department of Psychology and Neuroscience and the Center for Neuroscience, University of Colorado at Boulder, Boulder, Colorado 80309, United States
| | - Xiaozheng Zhang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China
| | - Timothy J. Fabisiak
- Department of Psychology and Neuroscience and the Center for Neuroscience, University of Colorado at Boulder, Boulder, Colorado 80309, United States
| | - Mackenzie E. Haas
- Department of Psychology and Neuroscience and the Center for Neuroscience, University of Colorado at Boulder, Boulder, Colorado 80309, United States
| | - Jose Amat
- Department of Psychology and Neuroscience and the Center for Neuroscience, University of Colorado at Boulder, Boulder, Colorado 80309, United States
| | - Hongyuan Li
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China
| | - Kenner C. Rice
- Drug Design and Synthesis Section, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland 20892, United States
| | - Steven F. Maier
- Department of Psychology and Neuroscience and the Center for Neuroscience, University of Colorado at Boulder, Boulder, Colorado 80309, United States
| | - Ryan K. Bachtell
- Department of Psychology and Neuroscience and the Center for Neuroscience, University of Colorado at Boulder, Boulder, Colorado 80309, United States
| | | | - Linda R. Watkins
- Department of Psychology and Neuroscience and the Center for Neuroscience, University of Colorado at Boulder, Boulder, Colorado 80309, United States
| |
Collapse
|
16
|
Chasing Uptake: Super-Resolution Microscopy in Endocytosis and Phagocytosis. Trends Cell Biol 2019; 29:727-739. [PMID: 31227311 DOI: 10.1016/j.tcb.2019.05.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/14/2019] [Accepted: 05/23/2019] [Indexed: 11/21/2022]
Abstract
Since their invention about two decades ago, super-resolution microscopes have become a method of choice in cell biology. Owing to a spatial resolution below 50 nm, smaller than the size of most organelles, and an order of magnitude better than the diffraction limit of conventional light microscopes, super-resolution microscopy is a powerful technique for resolving intracellular trafficking. In this review we discuss discoveries in endocytosis and phagocytosis that have been made possible by super-resolution microscopy - from uptake at the plasma membrane, endocytic coat formation, and cytoskeletal rearrangements to endosomal maturation. The detailed visualization of the diverse molecular assemblies that mediate endocytic uptake will provide a better understanding of how cells ingest extracellular material.
Collapse
|
17
|
Neumann J, Ziegler K, Gelléri M, Fröhlich-Nowoisky J, Liu F, Bellinghausen I, Schuppan D, Birk U, Pöschl U, Cremer C, Lucas K. Nanoscale distribution of TLR4 on primary human macrophages stimulated with LPS and ATI. NANOSCALE 2019; 11:9769-9779. [PMID: 31066732 DOI: 10.1039/c9nr00943d] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Toll-like receptor 4 (TLR4) plays a crucial role in the recognition of invading pathogens. Upon activation by lipopolysaccharides (LPS), TLR4 is recruited into specific membrane domains and dimerizes. In addition to LPS, TLR4 can be stimulated by wheat amylase-trypsin inhibitors (ATI). ATI are proteins associated with gluten containing grains, whose ingestion promotes intestinal and extraintestinal inflammation. However, the effect of ATI vs. LPS on the membrane distribution of TLR4 at the nanoscale has not been analyzed. In this study, we investigated the effect of LPS and ATI stimulation on the membrane distribution of TLR4 in primary human macrophages using single molecule localization microscopy (SMLM). We found that in unstimulated macrophages the majority of TLR4 molecules are located in clusters, but with donor-dependent variations from ∼51% to ∼75%. Depending on pre-clustering, we found pronounced variations in the fraction of clustered molecules and density of clusters on the membrane upon LPS and ATI stimulation. Although clustering differed greatly among the human donors, we found an almost constant cluster diameter of ∼44 nm for all donors, independent of treatment. Together, our results show donor-dependent but comparable effects between ATI and LPS stimulation on the membrane distribution of TLR4. This may indicate a general mechanism of TLR4 activation in primary human macrophages. Furthermore, our methodology visualizes TLR4 receptor clustering and underlines its functional role as a signaling platform.
Collapse
Affiliation(s)
- Jan Neumann
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Human Toll-Like Receptor 4 (hTLR4): Structural and functional dynamics in cancer. Int J Biol Macromol 2019; 122:425-451. [DOI: 10.1016/j.ijbiomac.2018.10.142] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 10/10/2018] [Accepted: 10/18/2018] [Indexed: 12/23/2022]
|
19
|
Widera D, Martínez Aguilar R, Cottrell GS. Toll-like receptor 4 and protease-activated receptor 2 in physiology and pathophysiology of the nervous system: more than just receptor cooperation? Neural Regen Res 2019; 14:1196-1201. [PMID: 30804245 PMCID: PMC6425834 DOI: 10.4103/1673-5374.251290] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Toll-like receptor 4 (TLR4) and protease-activated receptor 2 (PAR2) play pivotal roles in the mammalian innate immune response. Notably, in addition to their involvement in detection of invading pathogens, PAR2 and TLR4 modulate the levels of cell death-induced sterile inflammation by activating pro- or anti-inflammatory downstream signaling cascades. Within the central nervous system, there is emerging evidence that both receptors are involved in synaptic transmission and brain plasticity. Furthermore, due to their prominent role in mediating neuroinflammation, PAR2 and TLR4 are associated with development and progression of neurodegenerative disorders including but not limited to Alzheimer’s disease, Parkinson’s disease and multiple sclerosis. In this article, we summarise the current knowledge on the cooperation between PAR2 and TLR4, discuss the potential cross-talk levels and highlight the impact of the cross-coupling on neuroinflammation.
Collapse
Affiliation(s)
- Darius Widera
- Stem Cell Biology and Regenerative Medicine Group, School of Pharmacy, University of Reading, Whiteknights campus, Reading, UK
| | - Rocío Martínez Aguilar
- Stem Cell Biology and Regenerative Medicine Group, School of Pharmacy, University of Reading, Whiteknights campus, Reading, UK; Unidad de Inmunología, IBIMER, Universidad de Granada, Granada, Spain
| | - Graeme S Cottrell
- Cellular and Molecular Neuroscience, School of Pharmacy, University of Reading, Reading, UK
| |
Collapse
|
20
|
Jiang Y, Zhou J, Luo P, Gao H, Ma Y, Chen YS, Li L, Zou D, Zhang Y, Jing Z. Prosaposin promotes the proliferation and tumorigenesis of glioma through toll-like receptor 4 (TLR4)-mediated NF-κB signaling pathway. EBioMedicine 2018; 37:78-90. [PMID: 30385233 PMCID: PMC6286187 DOI: 10.1016/j.ebiom.2018.10.053] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 10/17/2018] [Accepted: 10/22/2018] [Indexed: 02/07/2023] Open
Abstract
Background As a neurotrophic factor, prosaposin (PSAP) can exert neuroprotective and neurotrophic effects. It is involved in the occurrence and development of prostate and breast cancer. However, there is no research about the role of PSAP in glioma. Methods The PSAP overexpressed or silenced glioma cells or glioma stem cells were established based on Lentiviral vector transfection. Cell viability assay, Edu assay, neurosphere formation assay and xenograft experiments were used to detect the proliferative ability. Western blot, Elisa and luciferase reporter assays were used to detect the possible mechanism. Findings Our study firstly found that PSAP was highly expressed and secreted in clinical glioma specimens, glioma stem cells, and glioma cell lines. It was associated with poor prognosis. We found that PSAP significantly promoted the proliferation of glioma stem cells and cell lines. Moreover, PSAP promoted tumorigenesis in subcutaneous and orthotopic models of this disease. Furthermore, GSEA and KEGG analysis predicted that PSAP acts through the TLR4 and NF-κB signaling pathways, which was confirmed by western blot, immunoprecipitation, immunofluorescence, and use of the TLR4-specific inhibitor TAK-242. Interpretation The findings of this study suggest that PSAP can promote glioma cell proliferation via the TLR4/NF-κB signaling pathway and may be an important target for glioma treatment. Fund This work was funded by National Natural Science Foundation of China (Nos. 81101917, 81270036, 81201802, 81673025), Program for Liaoning Excellent Talents in University (No. LR2014023), and Liaoning Province Natural Science Foundation (Nos. 20170541022, 20172250290). The funders did not play a role in manuscript design, data collection, data analysis, interpretation nor writing of the manuscript.
Collapse
Affiliation(s)
- Yang Jiang
- Department of Neurosurgery, The First Hospital of China Medical University, NO.155, North Nanjing Street, Heping District, Shenyang City 110001, China
| | - Jinpeng Zhou
- Department of Neurosurgery, The First Hospital of China Medical University, NO.155, North Nanjing Street, Heping District, Shenyang City 110001, China
| | - Peng Luo
- Department of Neurosurgery, The First Hospital of China Medical University, NO.155, North Nanjing Street, Heping District, Shenyang City 110001, China
| | - Huiling Gao
- College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Yanju Ma
- Department of Medical Oncology, Cancer Hospital of China Medical University, Shenyang 110042, China
| | - Yin-Sheng Chen
- Department of Neurosurgery/Neuro-oncology, SunYat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
| | - Long Li
- Department of Neurosurgery, The First Hospital of China Medical University, NO.155, North Nanjing Street, Heping District, Shenyang City 110001, China
| | - Dan Zou
- The First laboratory of cancer institute, The First Hospital of China Medical University, NO.155, North Nanjing Street, Heping District, Shenyang City 110001, China
| | - Ye Zhang
- The First laboratory of cancer institute, The First Hospital of China Medical University, NO.155, North Nanjing Street, Heping District, Shenyang City 110001, China.
| | - Zhitao Jing
- Department of Neurosurgery, The First Hospital of China Medical University, NO.155, North Nanjing Street, Heping District, Shenyang City 110001, China.
| |
Collapse
|
21
|
Oppelt A, Kaschek D, Huppelschoten S, Sison-Young R, Zhang F, Buck-Wiese M, Herrmann F, Malkusch S, Krüger CL, Meub M, Merkt B, Zimmermann L, Schofield A, Jones RP, Malik H, Schilling M, Heilemann M, van de Water B, Goldring CE, Park BK, Timmer J, Klingmüller U. Model-based identification of TNFα-induced IKKβ-mediated and IκBα-mediated regulation of NFκB signal transduction as a tool to quantify the impact of drug-induced liver injury compounds. NPJ Syst Biol Appl 2018; 4:23. [PMID: 29900006 PMCID: PMC5995845 DOI: 10.1038/s41540-018-0058-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 04/16/2018] [Accepted: 05/04/2018] [Indexed: 02/07/2023] Open
Abstract
Drug-induced liver injury (DILI) has become a major problem for patients and for clinicians, academics and the pharmaceutical industry. To date, existing hepatotoxicity test systems are only poorly predictive and the underlying mechanisms are still unclear. One of the factors known to amplify hepatotoxicity is the tumor necrosis factor alpha (TNFα), especially due to its synergy with commonly used drugs such as diclofenac. However, the exact mechanism of how diclofenac in combination with TNFα induces liver injury remains elusive. Here, we combined time-resolved immunoblotting and live-cell imaging data of HepG2 cells and primary human hepatocytes (PHH) with dynamic pathway modeling using ordinary differential equations (ODEs) to describe the complex structure of TNFα-induced NFκB signal transduction and integrated the perturbations of the pathway caused by diclofenac. The resulting mathematical model was used to systematically identify parameters affected by diclofenac. These analyses showed that more than one regulatory module of TNFα-induced NFκB signal transduction is affected by diclofenac, suggesting that hepatotoxicity is the integrated consequence of multiple changes in hepatocytes and that multiple factors define toxicity thresholds. Applying our mathematical modeling approach to other DILI-causing compounds representing different putative DILI mechanism classes enabled us to quantify their impact on pathway activation, highlighting the potential of the dynamic pathway model as a quantitative tool for the analysis of DILI compounds.
Collapse
Affiliation(s)
- Angela Oppelt
- 1Division Systems Biology of Signal Transduction, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Daniel Kaschek
- 2Institute of Physics, University of Freiburg, Freiburg, Germany
| | - Suzanna Huppelschoten
- 3Division of Toxicology, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Rowena Sison-Young
- 4MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Fang Zhang
- 4MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Marie Buck-Wiese
- 1Division Systems Biology of Signal Transduction, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Franziska Herrmann
- 1Division Systems Biology of Signal Transduction, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Sebastian Malkusch
- 5Institute of Physical and Theoretical Chemistry, Single Molecule Biophysics, Johann Wolfgang Goethe-University, Frankfurt, Germany
| | - Carmen L Krüger
- 5Institute of Physical and Theoretical Chemistry, Single Molecule Biophysics, Johann Wolfgang Goethe-University, Frankfurt, Germany
| | - Mara Meub
- 5Institute of Physical and Theoretical Chemistry, Single Molecule Biophysics, Johann Wolfgang Goethe-University, Frankfurt, Germany
| | - Benjamin Merkt
- 2Institute of Physics, University of Freiburg, Freiburg, Germany
| | - Lea Zimmermann
- 1Division Systems Biology of Signal Transduction, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Amy Schofield
- 4MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Robert P Jones
- 4MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK.,6North Western Hepatobiliary Unit, Aintree University Hospital NHS Foundation Trust, Liverpool, UK
| | - Hassan Malik
- 6North Western Hepatobiliary Unit, Aintree University Hospital NHS Foundation Trust, Liverpool, UK
| | - Marcel Schilling
- 1Division Systems Biology of Signal Transduction, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Mike Heilemann
- 5Institute of Physical and Theoretical Chemistry, Single Molecule Biophysics, Johann Wolfgang Goethe-University, Frankfurt, Germany.,7Bioquant, University of Heidelberg, Heidelberg, Germany
| | - Bob van de Water
- 3Division of Toxicology, Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Christopher E Goldring
- 4MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - B Kevin Park
- 4MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
| | - Jens Timmer
- 2Institute of Physics, University of Freiburg, Freiburg, Germany.,8BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Ursula Klingmüller
- 1Division Systems Biology of Signal Transduction, German Cancer Research Center (DKFZ), Heidelberg, Germany
| |
Collapse
|
22
|
Wang Z, Yu G, Liu Z, Zhu J, Chen C, Liu RE, Xu R. Paeoniflorin inhibits glioblastoma growth in vivo and in vitro: a role for the Triad3A-dependent ubiquitin proteasome pathway in TLR4 degradation. Cancer Manag Res 2018; 10:887-897. [PMID: 29740218 PMCID: PMC5931203 DOI: 10.2147/cmar.s160292] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background Paeoniflorin, a polyphenolic compound derived from Radix Paeoniae Alba (Paeonia lactiflora), has exhibited anticancer activity in various human cancers, including glioblastoma. However, the mechanisms underlying the effects of this compound have not been fully elucidated. Toll-like receptor 4 (TLR4) plays an important role in the regulation of cancer cell proliferation and progression, and high TLR4 expression in glioblastoma specimens is associated with a poor prognosis. The present study aimed to investigate whether paeoniflorin suppresses glioblastoma via inhibition of TLR4 expression. Methods CCK-8 experiments and clone formation assay were performed to detect the cell proliferation. Western blotting was used to analyze protein expression levels. Detection of Triad3A binding with TLR4 was assessed by the immunoprecipitation. Orthotopic xenograft mouse model was used to evaluate the effect of paeoniflorin in vivo. MST was used to analyze the interaction between paeoniflorin and TLR4 protein. Results In our study, we found that paeoniflorin effectively inhibited glioblastoma growth and suppressed TLR4 protein levels, as well its downstream effectors both in vivo and in vitro. Moreover, when overexpressed TLR4 in glioblastoma abolished the effects of paeoniflorin on cell proliferation, migration, and invasion. Furthermore, we found that paeoniflorin decreased TLR4 protein through ubiquitination proteasome pathway (UPP)-mediated degradation in glioblastoma cells. Mechanistically, paeoniflorin promoted Triad3A to conjugate with TLR4, resulting in degradation. In addition, Triad3A-shRNA abolished paeoniflorin-enhanced UPP-mediated TLR4 degradation. Finally, we found that paeoniflorin could directly bind with TLR4 protein as assessed by MST assay. Conclusion Our study is the first to identify a novel mechanism for the antitumor activity of paeoniflorin, specifically: it decreases tumor growth by directly targeting TLR4 and modulating the TLR4/Triad3A-dependent axis, leading to TLR4 protein degradation and inhibition of glioblastoma cell progression in vitro and in vivo. Our current findings indicate that paeoniflorin is a potential glioblastoma therapeutic agent due to its Triad3A-dependent ubiquitin degradation of TLR4.
Collapse
Affiliation(s)
- Zhaotao Wang
- Department of Neurosurgery, Affiliated Bayi Brain Hospital, General Army Hospital, Southern Medical University, Beijing, China
| | - Guoyong Yu
- Department of Neurosurgery, Jiangxi Provincial People's Hospital, Nanchang, China
| | - Zhi Liu
- Department of Neurosurgery, Peking University People's Hospital, Peking University, Beijing, China
| | - Jianwei Zhu
- Department of Neurosurgery, Affiliated Hospital of Traditional Chinese Medicine, Southwest Medical University, Luzhou, China
| | - Chen Chen
- Department of Neurosurgery, Affiliated Bayi Brain Hospital, General Army Hospital, Southern Medical University, Beijing, China
| | - Ru-En Liu
- Department of Neurosurgery, Peking University People's Hospital, Peking University, Beijing, China
| | - Ruxiang Xu
- Department of Neurosurgery, Affiliated Bayi Brain Hospital, General Army Hospital, Southern Medical University, Beijing, China
| |
Collapse
|
23
|
Krüger CL, Zeuner MT, Cottrell GS, Widera D, Heilemann M. Quantitative single-molecule imaging of TLR4 reveals ligand-specific receptor dimerization. Sci Signal 2017; 10:10/503/eaan1308. [DOI: 10.1126/scisignal.aan1308] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
24
|
Toll-Like Receptor 4 Signalling and Its Impact on Platelet Function, Thrombosis, and Haemostasis. Mediators Inflamm 2017; 2017:9605894. [PMID: 29170605 PMCID: PMC5664350 DOI: 10.1155/2017/9605894] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/17/2017] [Accepted: 09/12/2017] [Indexed: 11/18/2022] Open
Abstract
Platelets are anucleated blood cells that participate in a wide range of physiological and pathological functions. Their major role is mediating haemostasis and thrombosis. In addition to these classic functions, platelets have emerged as important players in the innate immune system. In particular, they interact with leukocytes, secrete pro- and anti-inflammatory factors, and express a wide range of inflammatory receptors including Toll-like receptors (TLRs), for example, Toll-like receptor 4 (TLR4). TLR4, which is the most extensively studied TLR in nucleated cells, recognises lipopolysaccharides (LPS) that are compounds of the outer surface of Gram-negative bacteria. Unlike other TLRs, TLR4 is able to signal through both the MyD88-dependent and MyD88-independent signalling pathways. Notably, despite both pathways culminating in the activation of transcription factors, TLR4 has a prominent functional impact on platelet activity, haemostasis, and thrombosis. In this review, we summarise the current knowledge on TLR4 signalling in platelets, critically discuss its impact on platelet function, and highlight the open questions in this area.
Collapse
|
25
|
Development and Characterisation of a Novel NF- κB Reporter Cell Line for Investigation of Neuroinflammation. Mediators Inflamm 2017; 2017:6209865. [PMID: 28790798 PMCID: PMC5534271 DOI: 10.1155/2017/6209865] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 06/19/2017] [Indexed: 01/22/2023] Open
Abstract
Aberrant activation of the transcription factor NF-κB, as well as uncontrolled inflammation, has been linked to autoimmune diseases, development and progression of cancer, and neurological disorders like Alzheimer's disease. Reporter cell lines are a valuable state-of-the art tool for comparative analysis of in vitro drug screening. However, a reporter cell line for the investigation of NF-κB-driven neuroinflammation has not been available. Thus, we developed a stable neural NF-κB-reporter cell line to assess the potency of proinflammatory molecules and peptides, as well as anti-inflammatory pharmaceuticals. We used lentivirus to transduce the glioma cell line U251-MG with a tandem NF-κB reporter construct containing GFP and firefly luciferase allowing an assessment of NF-κB activity via fluorescence microscopy, flow cytometry, and luminometry. We observed a robust activation of NF-κB after exposure of the reporter cell line to tumour necrosis factor alpha (TNFα) and amyloid-β peptide [1-42] as well as to LPS derived from Salmonella minnesota and Escherichia coli. Finally, we demonstrate that the U251-NF-κB-GFP-Luc reporter cells can be used for assessing the anti-inflammatory potential of pharmaceutical compounds using Bay11-7082 and IMD0354. In summary, our newly generated cell line is a robust and cost-efficient tool to study pro- and anti-inflammatory potential of drugs and biologics in neural cells.
Collapse
|
26
|
Han S, Wang C, Qin X, Xia J, Wu A. LPS alters the immuno-phenotype of glioma and glioma stem-like cells and induces in vivo antitumor immunity via TLR4. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2017. [PMID: 28641579 PMCID: PMC5480420 DOI: 10.1186/s13046-017-0552-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND This study examined the ability of lipopolysaccharide (LPS) to affect glioma and glioma stem-like cells (GSCs) in vitro and to induce antitumor immunity in vivo and the role of TLR4 in these processes. METHODS Using RT-PCR and immunohistochemistry, we examined the expression of TLR4 in 34 glioblastoma clinical samples. Using real time-PCR, western blot and ELISA analyses, the effect of LPS stimulation on the expression of immune related molecules was evaluated in RG2 and U87 GSCs. Control or LPS-pretreated RG2 GSCs were intracranially or subcutaneously implanted into wild-type or nude Fisher 344 rats. Histopathological examinations were used to assess tumor progression and immune infiltration and Kaplan-Meier analyses to compare survival times of the animal models. RESULTS TLR4 was highly expressed in glioblastoma clinical samples. In vitro LPS stimulation for 6 h significantly altered expression of immune related molecules in RG2 and U87 GSCs. However, prolonged LPS stimulation diminished this effect. Rats inoculated intracranially with LPS-pretreated RG2 GSCs survived significantly longer than rats inoculated with control RG2 GSCs. In vivo, LPS-pretreated RG2 GSCs expressed higher levels of MHC molecules, CXCL10 and TNF-α and recruited more CD8+ lymphocytes. However, intratumoral LPS treatment was not equally beneficial. Furthermore, the in vitro and in vivo effects of LPS stimulation appeared to be largely TLR4-dependent. CONCLUSION LPS pretreatment promotes the recognition and eradication of tumor GSCs in vivo when the immune function of the tumor-bearing host is intact. In addition, our data indicate a complex relationship between bacterial infection and glioma prognosis.
Collapse
Affiliation(s)
- Sheng Han
- Department of Neurosurgery, The First Hospital of China Medical University, Nanjing Street 155, Heping District, Shenyang, 110001, China
| | - Chao Wang
- Department of Neurosurgery, The First Hospital of China Medical University, Nanjing Street 155, Heping District, Shenyang, 110001, China
| | - Xiaofei Qin
- Department of Neurosurgery, The First Hospital of China Medical University, Nanjing Street 155, Heping District, Shenyang, 110001, China
| | - Junzhe Xia
- Department of Neurosurgery, The First Hospital of China Medical University, Nanjing Street 155, Heping District, Shenyang, 110001, China
| | - Anhua Wu
- Department of Neurosurgery, The First Hospital of China Medical University, Nanjing Street 155, Heping District, Shenyang, 110001, China.
| |
Collapse
|
27
|
Abstract
Super-resolution fluorescence imaging by photoactivation or photoswitching of single fluorophores and position determination (single-molecule localization microscopy, SMLM) provides microscopic images with subdiffraction spatial resolution. This technology has enabled new insights into how proteins are organized in a cellular context, with a spatial resolution approaching virtually the molecular level. A unique strength of SMLM is that it delivers molecule-resolved information, along with super-resolved images of cellular structures. This allows quantitative access to cellular structures, for example, how proteins are distributed and organized and how they interact with other biomolecules. Ultimately, it is even possible to determine protein numbers in cells and the number of subunits in a protein complex. SMLM thus has the potential to pave the way toward a better understanding of how cells function at the molecular level. In this review, we describe how SMLM has contributed new knowledge in eukaryotic biology, and we specifically focus on quantitative biological data extracted from SMLM images.
Collapse
Affiliation(s)
- Markus Sauer
- Department of Biotechnology & Biophysics, Julius-Maximilian-University of Würzburg , 97074 Würzburg, Germany
| | - Mike Heilemann
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt , 60438 Frankfurt, Germany
| |
Collapse
|