51
|
Drug-Targeted Genomes: Mutability of Ion Channels and GPCRs. Biomedicines 2022; 10:biomedicines10030594. [PMID: 35327396 PMCID: PMC8945769 DOI: 10.3390/biomedicines10030594] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 02/24/2022] [Accepted: 03/01/2022] [Indexed: 02/04/2023] Open
Abstract
Mutations of ion channels and G-protein-coupled receptors (GPCRs) are not uncommon and can lead to cardiovascular diseases. Given previously reported multiple factors associated with high mutation rates, we sorted the relative mutability of multiple human genes by (i) proximity to telomeres and/or (ii) high adenine and thymine (A+T) content. We extracted genomic information using the genome data viewer and examined the mutability of 118 ion channel and 143 GPCR genes based on their association with factors (i) and (ii). We then assessed these two factors with 31 genes encoding ion channels or GPCRs that are targeted by the United States Food and Drug Administration (FDA)-approved drugs. Out of the 118 ion channel genes studied, 80 met either factor (i) or (ii), resulting in a 68% match. In contrast, a 78% match was found for the 143 GPCR genes. We also found that the GPCR genes (n = 20) targeted by FDA-approved drugs have a relatively lower mutability than those genes encoding ion channels (n = 11), where targeted genes encoding GPCRs were shorter in length. The result of this study suggests that the use of matching rate analysis on factor-druggable genome is feasible to systematically compare the relative mutability of GPCRs and ion channels. The analysis on chromosomes by two factors identified a unique characteristic of GPCRs, which have a significant relationship between their nucleotide sizes and proximity to telomeres, unlike most genetic loci susceptible to human diseases.
Collapse
|
52
|
Somogyi AA, Musolino ST, Barratt DT. New pharmacological perspectives and therapeutic options for opioids: Differences matter. Anaesth Intensive Care 2022; 50:127-140. [PMID: 35112584 DOI: 10.1177/0310057x211063891] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Opioids remain the major drug class for the treatment of acute, chronic and cancer pain, but have major harmful effects such as dependence and opioid-induced ventilatory impairment. Although no new typical opioids have come onto the market in the past almost 50 years, a plethora of new innovative formulations has been developed to meet the clinical need. This review is intended to shed light on new understanding of the molecular pharmacology of opioids, which has arisen largely due to the genomic revolution, and what new drugs may become available in the coming years. Atypical opioids have and are being developed which not only target the mu opioid receptor but other targets in the pain pathway. Biased mu agonists have been developed but remain 'unbiased' clinically. The contribution of drugs targeting non-mu opioid receptors either alone or as heterodimers shows potential promise but remains understudied. That gene splice variants of the mu opioid receptor produce multiple receptor isoforms in different brain regions, and may change with pain chronicity and phenotype, presents new challenges but also opportunities for precision pain medicine. Finally, that opioids also have pro-inflammatory effects not aligned with mu opioid receptor binding affinity implicates a fresh understanding of their role in chronic pain, whether cancer or non-cancer. Hopefully, a new understanding of opioid analgesic drug action may lead to new drug development and better precision medicine in acute and chronic pain relief with less patient harm.
Collapse
Affiliation(s)
- Andrew A Somogyi
- Discipline of Pharmacology, University of Adelaide, Adelaide, Australia
| | - Stefan T Musolino
- Discipline of Pharmacology, University of Adelaide, Adelaide, Australia
| | - Daniel T Barratt
- Discipline of Physiology, University of Adelaide, Adelaide, Australia
| |
Collapse
|
53
|
Agonist-induced phosphorylation of orthologues of the orphan receptor GPR35 functions as an activation sensor. J Biol Chem 2022; 298:101655. [PMID: 35101446 PMCID: PMC8892012 DOI: 10.1016/j.jbc.2022.101655] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 12/29/2022] Open
Abstract
G protein-coupled receptor 35 (GPR35) is poorly characterized but nevertheless has been revealed to have diverse roles in areas including lower gut inflammation and pain. The development of novel reagents and tools will greatly enhance analysis of GPR35 functions in health and disease. Here, we used mass spectrometry, mutagenesis, and [32P] orthophosphate labeling to identify that all five hydroxy-amino acids in the C-terminal tail of human GPR35a became phosphorylated in response to agonist occupancy of the receptor and that, apart from Ser294, each of these contributed to interactions with arretin-3, which inhibits further G protein-coupled receptor signaling. We found that Ser303 was key to such interactions; the serine corresponding to human GPR35a residue 303 also played a dominant role in arrestin-3 interactions for both mouse and rat GPR35. We also demonstrated that fully phospho-site–deficient mutants of human GPR35a and mouse GPR35 failed to interact effectively with arrestin-3, and the human phospho-deficient variant was not internalized from the surface of cells in response to agonist treatment. Even in cells stably expressing species orthologues of GPR35, a substantial proportion of the expressed protein(s) was determined to be immature. Finally, phospho-site–specific antisera targeting the region encompassing Ser303 in human (Ser301 in mouse) GPR35a identified only the mature forms of GPR35 and provided effective sensors of the activation status of the receptors both in immunoblotting and immunocytochemical studies. Such antisera may be useful tools to evaluate target engagement in drug discovery and target validation programs.
Collapse
|
54
|
Liu QR, Aseer KR, Yao Q, Zhong X, Ghosh P, O’Connell JF, Egan JM. Anti-Inflammatory and Pro-Autophagy Effects of the Cannabinoid Receptor CB2R: Possibility of Modulation in Type 1 Diabetes. Front Pharmacol 2022; 12:809965. [PMID: 35115945 PMCID: PMC8804091 DOI: 10.3389/fphar.2021.809965] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/21/2021] [Indexed: 11/13/2022] Open
Abstract
Type 1 diabetes mellitus (T1DM) is an autoimmune disease resulting from loss of insulin-secreting β-cells in islets of Langerhans. The loss of β-cells is initiated when self-tolerance to β-cell-derived contents breaks down, which leads to T cell-mediated β-cell damage and, ultimately, β-cell apoptosis. Many investigations have demonstrated the positive effects of antagonizing cannabinoid receptor 1 (CB1R) in metabolic diseases such as fatty liver disease, obesity, and diabetes mellitus, but the role of cannabinoid receptor 2 (CB2R) in such diseases is relatively unknown. Activation of CB2R is known for its immunosuppressive roles in multiple sclerosis, rheumatoid arthritis, Crohn’s, celiac, and lupus diseases, and since autoimmune diseases can share common environmental and genetic factors, we propose CB2R specific agonists may also serve as disease modifiers in diabetes mellitus. The CNR2 gene, which encodes CB2R protein, is the result of a gene duplication of CNR1, which encodes CB1R protein. This ortholog evolved rapidly after transitioning from invertebrates to vertebrate hundreds of million years ago. Human specific CNR2 isoforms are induced by inflammation in pancreatic islets, and a CNR2 nonsynonymous SNP (Q63R) is associated with autoimmune diseases. We collected evidence from the literature and from our own studies demonstrating that CB2R is involved in regulating the inflammasome and especially release of the cytokine interleukin 1B (IL-1β). Furthermore, CB2R activation controls intracellular autophagy and may regulate secretion of extracellular vesicles from adipocytes that participate in recycling of lipid droplets, dysregulation of which induces chronic inflammation and obesity. CB2R activation may play a similar role in islets of Langerhans. Here, we will discuss future strategies to unravel what roles, if any, CB2R modifiers potentially play in T1DM.
Collapse
Affiliation(s)
- Qing-Rong Liu
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD, United States
- *Correspondence: Qing-Rong Liu, ; Josephine M. Egan,
| | - Kanikkai Raja Aseer
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD, United States
| | - Qin Yao
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD, United States
| | - Xiaoming Zhong
- Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, United States
| | - Paritosh Ghosh
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD, United States
| | - Jennifer F. O’Connell
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD, United States
| | - Josephine M. Egan
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD, United States
- *Correspondence: Qing-Rong Liu, ; Josephine M. Egan,
| |
Collapse
|
55
|
Zhang CY, Xiao X, Zhang Z, Hu Z, Li M. An alternative splicing hypothesis for neuropathology of schizophrenia: evidence from studies on historical candidate genes and multi-omics data. Mol Psychiatry 2022; 27:95-112. [PMID: 33686213 DOI: 10.1038/s41380-021-01037-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 01/08/2021] [Accepted: 01/22/2021] [Indexed: 01/31/2023]
Abstract
Alternative splicing of schizophrenia risk genes, such as DRD2, GRM3, and DISC1, has been extensively described. Nevertheless, the alternative splicing characteristics of the growing number of schizophrenia risk genes identified through genetic analyses remain relatively opaque. Recently, transcriptomic analyses in human brains based on short-read RNA-sequencing have discovered many "local splicing" events (e.g., exon skipping junctions) associated with genetic risk of schizophrenia, and further molecular characterizations have identified novel spliced isoforms, such as AS3MTd2d3 and ZNF804AE3E4. In addition, long-read sequencing analyses of schizophrenia risk genes (e.g., CACNA1C and NRXN1) have revealed multiple previously unannotated brain-abundant isoforms with therapeutic potentials, and functional analyses of KCNH2-3.1 and Ube3a1 have provided examples for investigating such spliced isoforms in vitro and in vivo. These findings suggest that alternative splicing may be an essential molecular mechanism underlying genetic risk of schizophrenia, however, the incomplete annotations of human brain transcriptomes might have limited our understanding of schizophrenia pathogenesis, and further efforts to elucidate these transcriptional characteristics are urgently needed to gain insights into the illness-correlated brain physiology and pathology as well as to translate genetic discoveries into novel therapeutic targets.
Collapse
Affiliation(s)
- Chu-Yi Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Xiao Xiao
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.,KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Zhuohua Zhang
- Institute of Molecular Precision Medicine and Hunan Key Laboratory of Molecular Precision Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Zhonghua Hu
- Institute of Molecular Precision Medicine and Hunan Key Laboratory of Molecular Precision Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China. .,Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China. .,Department of Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, Hunan, China. .,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, China. .,Hunan Key Laboratory of Animal Models for Human Diseases, School of Life Sciences, Central South University, Changsha, Hunan, China. .,Eye Center of Xiangya Hospital and Hunan Key Laboratory of Ophthalmology, Central South University, Changsha, Hunan, China. .,National Clinical Research Center on Mental Disorders, Changsha, Hunan, China.
| | - Ming Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China. .,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, China. .,KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.
| |
Collapse
|
56
|
Cong Z, Liang YL, Zhou Q, Darbalaei S, Zhao F, Feng W, Zhao L, Xu HE, Yang D, Wang MW. Structural perspective of class B1 GPCR signaling. Trends Pharmacol Sci 2022; 43:321-334. [DOI: 10.1016/j.tips.2022.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 01/01/2022] [Accepted: 01/03/2022] [Indexed: 12/12/2022]
|
57
|
Leysen H, Walter D, Christiaenssen B, Vandoren R, Harputluoğlu İ, Van Loon N, Maudsley S. GPCRs Are Optimal Regulators of Complex Biological Systems and Orchestrate the Interface between Health and Disease. Int J Mol Sci 2021; 22:ijms222413387. [PMID: 34948182 PMCID: PMC8708147 DOI: 10.3390/ijms222413387] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 12/08/2021] [Accepted: 12/09/2021] [Indexed: 02/06/2023] Open
Abstract
GPCRs arguably represent the most effective current therapeutic targets for a plethora of diseases. GPCRs also possess a pivotal role in the regulation of the physiological balance between healthy and pathological conditions; thus, their importance in systems biology cannot be underestimated. The molecular diversity of GPCR signaling systems is likely to be closely associated with disease-associated changes in organismal tissue complexity and compartmentalization, thus enabling a nuanced GPCR-based capacity to interdict multiple disease pathomechanisms at a systemic level. GPCRs have been long considered as controllers of communication between tissues and cells. This communication involves the ligand-mediated control of cell surface receptors that then direct their stimuli to impact cell physiology. Given the tremendous success of GPCRs as therapeutic targets, considerable focus has been placed on the ability of these therapeutics to modulate diseases by acting at cell surface receptors. In the past decade, however, attention has focused upon how stable multiprotein GPCR superstructures, termed receptorsomes, both at the cell surface membrane and in the intracellular domain dictate and condition long-term GPCR activities associated with the regulation of protein expression patterns, cellular stress responses and DNA integrity management. The ability of these receptorsomes (often in the absence of typical cell surface ligands) to control complex cellular activities implicates them as key controllers of the functional balance between health and disease. A greater understanding of this function of GPCRs is likely to significantly augment our ability to further employ these proteins in a multitude of diseases.
Collapse
Affiliation(s)
- Hanne Leysen
- Receptor Biology Lab, University of Antwerp, 2610 Wilrijk, Belgium; (H.L.); (D.W.); (B.C.); (R.V.); (İ.H.); (N.V.L.)
| | - Deborah Walter
- Receptor Biology Lab, University of Antwerp, 2610 Wilrijk, Belgium; (H.L.); (D.W.); (B.C.); (R.V.); (İ.H.); (N.V.L.)
| | - Bregje Christiaenssen
- Receptor Biology Lab, University of Antwerp, 2610 Wilrijk, Belgium; (H.L.); (D.W.); (B.C.); (R.V.); (İ.H.); (N.V.L.)
| | - Romi Vandoren
- Receptor Biology Lab, University of Antwerp, 2610 Wilrijk, Belgium; (H.L.); (D.W.); (B.C.); (R.V.); (İ.H.); (N.V.L.)
| | - İrem Harputluoğlu
- Receptor Biology Lab, University of Antwerp, 2610 Wilrijk, Belgium; (H.L.); (D.W.); (B.C.); (R.V.); (İ.H.); (N.V.L.)
- Department of Chemistry, Middle East Technical University, Çankaya, Ankara 06800, Turkey
| | - Nore Van Loon
- Receptor Biology Lab, University of Antwerp, 2610 Wilrijk, Belgium; (H.L.); (D.W.); (B.C.); (R.V.); (İ.H.); (N.V.L.)
| | - Stuart Maudsley
- Receptor Biology Lab, University of Antwerp, 2610 Wilrijk, Belgium; (H.L.); (D.W.); (B.C.); (R.V.); (İ.H.); (N.V.L.)
- Correspondence:
| |
Collapse
|
58
|
Lin LC, Quon T, Engberg S, Mackenzie AE, Tobin AB, Milligan G. G Protein-Coupled Receptor GPR35 Suppresses Lipid Accumulation in Hepatocytes. ACS Pharmacol Transl Sci 2021; 4:1835-1848. [PMID: 34927014 DOI: 10.1021/acsptsci.1c00224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Indexed: 02/07/2023]
Abstract
Although prevalent, nonalcoholic fatty liver disease is not currently treated effectively with medicines. Initially, using wild-type and genome-edited clones of the human hepatocyte cell line HepG2, we show that activation of the orphan G protein-coupled receptor GPR35 is both able and sufficient to block liver X-receptor-mediated lipid accumulation. Studies on hepatocytes isolated from both wild-type and GPR35 knock-out mice were consistent with a similar effect of GPR35 agonists in these cells, but because of marked differences in the pharmacology of GPR35 agonists and antagonists at the mouse and human orthologues, as well as elevated basal lipid levels in hepatocytes from the GPR35 knock-out mice, no definitive conclusion could be reached. To overcome this, we generated and characterized a transgenic knock-in mouse line in which the corresponding human GPR35 splice variant replaced the mouse orthologue. In hepatocytes from these humanized GPR35 mice, activation of this receptor was shown conclusively to prevent, and also reverse, lipid accumulation induced by liver X-receptor stimulation. These studies highlight the potential to target GPR35 in the context of fatty liver diseases.
Collapse
Affiliation(s)
- Li-Chiung Lin
- The Centre for Translational Pharmacology, Institute of Molecular, Cellular and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Tezz Quon
- The Centre for Translational Pharmacology, Institute of Molecular, Cellular and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Susanna Engberg
- Discovery Biology, Discovery Sciences, R&D, AstraZeneca, Pepparedsleden 1, 431 83 Mölndal, Sweden
| | - Amanda E Mackenzie
- The Centre for Translational Pharmacology, Institute of Molecular, Cellular and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Andrew B Tobin
- The Centre for Translational Pharmacology, Institute of Molecular, Cellular and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Graeme Milligan
- The Centre for Translational Pharmacology, Institute of Molecular, Cellular and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| |
Collapse
|
59
|
Louadi Z, Elkjaer ML, Klug M, Lio CT, Fenn A, Illes Z, Bongiovanni D, Baumbach J, Kacprowski T, List M, Tsoy O. Functional enrichment of alternative splicing events with NEASE reveals insights into tissue identity and diseases. Genome Biol 2021; 22:327. [PMID: 34857024 PMCID: PMC8638120 DOI: 10.1186/s13059-021-02538-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 11/10/2021] [Indexed: 01/27/2023] Open
Abstract
Alternative splicing (AS) is an important aspect of gene regulation. Nevertheless, its role in molecular processes and pathobiology is far from understood. A roadblock is that tools for the functional analysis of AS-set events are lacking. To mitigate this, we developed NEASE, a tool integrating pathways with structural annotations of protein-protein interactions to functionally characterize AS events. We show in four application cases how NEASE can identify pathways contributing to tissue identity and cell type development, and how it highlights splicing-related biomarkers. With a unique view on AS, NEASE generates unique and meaningful biological insights complementary to classical pathways analysis.
Collapse
Affiliation(s)
- Zakaria Louadi
- Chair of Experimental Bioinformatics, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
- Institute for Computational Systems Biology, University of Hamburg, Notkestrasse 9, 22607, Hamburg, Germany
| | - Maria L Elkjaer
- Department of Neurology, Odense University Hospital, Odense, Denmark
- Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
- Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Melissa Klug
- Chair of Experimental Bioinformatics, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
- Department of Internal Medicine I, School of Medicine, University hospital rechts der Isar, Technical University of Munich, Munich, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany
| | - Chit Tong Lio
- Chair of Experimental Bioinformatics, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
- Institute for Computational Systems Biology, University of Hamburg, Notkestrasse 9, 22607, Hamburg, Germany
| | - Amit Fenn
- Chair of Experimental Bioinformatics, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
- Institute for Computational Systems Biology, University of Hamburg, Notkestrasse 9, 22607, Hamburg, Germany
| | - Zsolt Illes
- Department of Neurology, Odense University Hospital, Odense, Denmark
- Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
- Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Dario Bongiovanni
- Department of Internal Medicine I, School of Medicine, University hospital rechts der Isar, Technical University of Munich, Munich, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany
- Department of Cardiovascular Medicine, Humanitas Clinical and Research Center IRCCS and Humanitas University, Rozzano, Milan, Italy
| | - Jan Baumbach
- Institute for Computational Systems Biology, University of Hamburg, Notkestrasse 9, 22607, Hamburg, Germany
- Institute of Mathematics and Computer Science, University of Southern Denmark, Campusvej 55, 5000, Odense, Denmark
| | - Tim Kacprowski
- Division Data Science in Biomedicine, Peter L. Reichertz Institute for Medical Informatics of Technische Universität Braunschweig and Hannover Medical School, Braunschweig, Germany
- Braunschweig Integrated Centre of Systems Biology (BRICS), TU Braunschweig, Braunschweig, Germany
| | - Markus List
- Chair of Experimental Bioinformatics, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany.
| | - Olga Tsoy
- Institute for Computational Systems Biology, University of Hamburg, Notkestrasse 9, 22607, Hamburg, Germany.
| |
Collapse
|
60
|
Karakulak T, Moch H, von Mering C, Kahraman A. Probing Isoform Switching Events in Various Cancer Types: Lessons From Pan-Cancer Studies. Front Mol Biosci 2021; 8:726902. [PMID: 34888349 PMCID: PMC8650491 DOI: 10.3389/fmolb.2021.726902] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 11/01/2021] [Indexed: 12/03/2022] Open
Abstract
Alternative splicing is an essential regulatory mechanism for gene expression in mammalian cells contributing to protein, cellular, and species diversity. In cancer, alternative splicing is frequently disturbed, leading to changes in the expression of alternatively spliced protein isoforms. Advances in sequencing technologies and analysis methods led to new insights into the extent and functional impact of disturbed alternative splicing events. In this review, we give a brief overview of the molecular mechanisms driving alternative splicing, highlight the function of alternative splicing in healthy tissues and describe how alternative splicing is disrupted in cancer. We summarize current available computational tools for analyzing differential transcript usage, isoform switching events, and the pathogenic impact of cancer-specific splicing events. Finally, the strategies of three recent pan-cancer studies on isoform switching events are compared. Their methodological similarities and discrepancies are highlighted and lessons learned from the comparison are listed. We hope that our assessment will lead to new and more robust methods for cancer-specific transcript detection and help to produce more accurate functional impact predictions of isoform switching events.
Collapse
Affiliation(s)
- Tülay Karakulak
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland
- Swiss Informatics Institute, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Holger Moch
- Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland
- Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Christian von Mering
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- Swiss Informatics Institute, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Abdullah Kahraman
- Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland
- Swiss Informatics Institute, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| |
Collapse
|
61
|
Axonal CB1 Receptors Mediate Inhibitory Bouton Formation via cAMP Increase and PKA. J Neurosci 2021; 41:8279-8296. [PMID: 34413209 DOI: 10.1523/jneurosci.0851-21.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/30/2021] [Accepted: 07/25/2021] [Indexed: 12/11/2022] Open
Abstract
Experience-dependent formation and removal of inhibitory synapses are essential throughout life. For instance, GABAergic synapses are removed to facilitate learning, and strong excitatory activity is accompanied by the formation of inhibitory synapses to maintain coordination between excitation and inhibition. We recently discovered that active dendrites trigger the growth of inhibitory synapses via CB1 receptor-mediated endocannabinoid signaling, but the underlying mechanism remained unclear. Using two-photon microscopy to monitor the formation of individual inhibitory boutons in hippocampal organotypic slices from mice (both sexes), we found that CB1 receptor activation mediated the formation of inhibitory boutons and promoted their subsequent stabilization. Inhibitory bouton formation did not require neuronal activity and was independent of Gi/o-protein signaling, but was directly induced by elevating cAMP levels using forskolin and by activating Gs-proteins using DREADDs. Blocking PKA activity prevented CB1 receptor-mediated inhibitory bouton formation. Our findings reveal that axonal CB1 receptors signal via unconventional downstream pathways and that inhibitory bouton formation is triggered by an increase in axonal cAMP levels. Our results demonstrate an unexpected role for axonal CB1 receptors in axon-specific, and context-dependent, inhibitory synapse formation.SIGNIFICANCE STATEMENT Coordination between excitation and inhibition is required for proper brain function throughout life. It was previously shown that new inhibitory synapses can be formed in response to strong excitation to maintain this coordination, and this was mediated by endocannabinoid signaling via CB1 receptors. As activation of CB1 receptors generally results in the suppression of synaptic transmission, it remained unclear how CB1 receptors can mediate the formation of inhibitory synapses. Here we show that CB1 receptors on inhibitory axons signal via unconventional intracellular pathways and that inhibitory bouton formation is triggered by an increase in axonal cAMP levels and requires PKA activity. Our findings point to a central role for axonal cAMP signaling in activity-dependent inhibitory synapse formation.
Collapse
|
62
|
Tasma Z, Siow A, Harris PWR, Brimble MA, Hay DL, Walker CS. Characterisation of agonist signalling profiles and agonist-dependent antagonism at PACAP-responsive receptors: Implications for drug discovery. Br J Pharmacol 2021; 179:435-453. [PMID: 34612509 DOI: 10.1111/bph.15700] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 08/16/2021] [Accepted: 08/30/2021] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND AND PURPOSE The pituitary adenylate cyclase-activating peptide (PACAP) family is of clinical interest for the treatment of migraine. These peptides activate three different PACAP-responsive class B G protein-coupled receptors: the PAC1 , VPAC1 and VPAC2 receptors. The PAC1 receptor may be alternatively spliced, generating variants that can differ in their pharmacological or signalling profiles. To inform drug discovery efforts targeting migraine, we need to better understand how the different PACAP-responsive receptors signal and how effectively these responses can be blocked by antagonists. EXPERIMENTAL APPROACH The signalling profiles of the human PAC1n , PAC1s , VPAC1 and VPAC2 receptors were examined in transfected Cos7 cells for cAMP, IP1 , pAkt, pERK and pCREB. Biased signalling was then quantified. The ability of antagonists to block PACAP-38, PACAP-27 or VIP stimulated cAMP accumulation at PACAP-responsive receptors was also determined. KEY RESULTS PACAP-responsive receptors exhibited varied pharmacological profiles but activated signalling in a similar manner. The PAC1n and PAC1s receptors displayed distinct pharmacology. At the PAC1s receptor, VIP and PHM were more potent than at the PAC1n receptor. PACAP-responsive receptors displayed agonist-dependent antagonism where PACAP-38 was less effectively antagonised compared to PACAP-27 and VIP. CONCLUSIONS AND IMPLICATIONS The distinct pharmacological profile displayed by the PAC1s receptor suggests that it can act as a dual receptor for VIP and PACAP. Furthermore, the effectiveness of blocking a signalling pathway can be influenced by which endogenous PACAP family agonist is present. These effects have potential implications for the development and effectiveness of drugs targeting the PACAP system.
Collapse
Affiliation(s)
- Zoe Tasma
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Andrew Siow
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | - Paul W R Harris
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,School of Chemical Sciences, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre and Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Margaret A Brimble
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,School of Chemical Sciences, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre and Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Debbie L Hay
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre and Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.,Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand
| | - Christopher S Walker
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre and Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| |
Collapse
|
63
|
Constitutive signal bias mediated by the human GHRHR splice variant 1. Proc Natl Acad Sci U S A 2021; 118:2106606118. [PMID: 34599099 PMCID: PMC8501799 DOI: 10.1073/pnas.2106606118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2021] [Indexed: 11/18/2022] Open
Abstract
The mechanism of functional changes induced by alternative splicing of GHRHR is largely unknown. Here, we demonstrate that GHRH-elicited signal bias toward β-arrestin recruitment is constitutively mediated by SV1. The cryogenic electron microscopy structures of SV1 and molecular dynamics simulations reveal the different functionalities between GHRHR and SV1 at the near-atomic level (i.e., the N termini of GHRHR and SV1 differentiate the downstream signaling pathways, Gs versus β-arrestins). Our findings provide valuable insights into the functional diversity of class B1 GPCRs that may aid in the design of better therapeutic agents against certain cancers. Alternative splicing of G protein–coupled receptors has been observed, but their functions are largely unknown. Here, we report that a splice variant (SV1) of the human growth hormone–releasing hormone receptor (GHRHR) is capable of transducing biased signal. Differing only at the receptor N terminus, GHRHR predominantly activates Gs while SV1 selectively couples to β-arrestins. Based on the cryogenic electron microscopy structures of SV1 in the apo state or GHRH-bound state in complex with the Gs protein, molecular dynamics simulations reveal that the N termini of GHRHR and SV1 differentiate the downstream signaling pathways, Gs versus β-arrestins. As suggested by mutagenesis and functional studies, it appears that GHRH-elicited signal bias toward β-arrestin recruitment is constitutively mediated by SV1. The level of SV1 expression in prostate cancer cells is also positively correlated with ERK1/2 phosphorylation but negatively correlated with cAMP response. Our findings imply that constitutive signal bias may be a mechanism that ensures cancer cell proliferation.
Collapse
|
64
|
Ramms DJ, Raimondi F, Arang N, Herberg FW, Taylor SS, Gutkind JS. G αs-Protein Kinase A (PKA) Pathway Signalopathies: The Emerging Genetic Landscape and Therapeutic Potential of Human Diseases Driven by Aberrant G αs-PKA Signaling. Pharmacol Rev 2021; 73:155-197. [PMID: 34663687 PMCID: PMC11060502 DOI: 10.1124/pharmrev.120.000269] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Many of the fundamental concepts of signal transduction and kinase activity are attributed to the discovery and crystallization of cAMP-dependent protein kinase, or protein kinase A. PKA is one of the best-studied kinases in human biology, with emphasis in biochemistry and biophysics, all the way to metabolism, hormone action, and gene expression regulation. It is surprising, however, that our understanding of PKA's role in disease is largely underappreciated. Although genetic mutations in the PKA holoenzyme are known to cause diseases such as Carney complex, Cushing syndrome, and acrodysostosis, the story largely stops there. With the recent explosion of genomic medicine, we can finally appreciate the broader role of the Gαs-PKA pathway in disease, with contributions from aberrant functioning G proteins and G protein-coupled receptors, as well as multiple alterations in other pathway components and negative regulators. Together, these represent a broad family of diseases we term the Gαs-PKA pathway signalopathies. The Gαs-PKA pathway signalopathies encompass diseases caused by germline, postzygotic, and somatic mutations in the Gαs-PKA pathway, with largely endocrine and neoplastic phenotypes. Here, we present a signaling-centric review of Gαs-PKA-driven pathophysiology and integrate computational and structural analysis to identify mutational themes commonly exploited by the Gαs-PKA pathway signalopathies. Major mutational themes include hotspot activating mutations in Gαs, encoded by GNAS, and mutations that destabilize the PKA holoenzyme. With this review, we hope to incite further study and ultimately the development of new therapeutic strategies in the treatment of a wide range of human diseases. SIGNIFICANCE STATEMENT: Little recognition is given to the causative role of Gαs-PKA pathway dysregulation in disease, with effects ranging from infectious disease, endocrine syndromes, and many cancers, yet these disparate diseases can all be understood by common genetic themes and biochemical signaling connections. By highlighting these common pathogenic mechanisms and bridging multiple disciplines, important progress can be made toward therapeutic advances in treating Gαs-PKA pathway-driven disease.
Collapse
Affiliation(s)
- Dana J Ramms
- Department of Pharmacology (D.J.R., N.A., J.S.G.), Department of Chemistry and Biochemistry (S.S.T.), and Moores Cancer Center (D.J.R., N.A., J.S.G.), University of California, San Diego, La Jolla, California; Laboratorio di Biologia Bio@SNS, Scuola Normale Superiore, Pisa, Italy (F.R.); and Department of Biochemistry, University of Kassel, Kassel, Germany (F.W.H.)
| | - Francesco Raimondi
- Department of Pharmacology (D.J.R., N.A., J.S.G.), Department of Chemistry and Biochemistry (S.S.T.), and Moores Cancer Center (D.J.R., N.A., J.S.G.), University of California, San Diego, La Jolla, California; Laboratorio di Biologia Bio@SNS, Scuola Normale Superiore, Pisa, Italy (F.R.); and Department of Biochemistry, University of Kassel, Kassel, Germany (F.W.H.)
| | - Nadia Arang
- Department of Pharmacology (D.J.R., N.A., J.S.G.), Department of Chemistry and Biochemistry (S.S.T.), and Moores Cancer Center (D.J.R., N.A., J.S.G.), University of California, San Diego, La Jolla, California; Laboratorio di Biologia Bio@SNS, Scuola Normale Superiore, Pisa, Italy (F.R.); and Department of Biochemistry, University of Kassel, Kassel, Germany (F.W.H.)
| | - Friedrich W Herberg
- Department of Pharmacology (D.J.R., N.A., J.S.G.), Department of Chemistry and Biochemistry (S.S.T.), and Moores Cancer Center (D.J.R., N.A., J.S.G.), University of California, San Diego, La Jolla, California; Laboratorio di Biologia Bio@SNS, Scuola Normale Superiore, Pisa, Italy (F.R.); and Department of Biochemistry, University of Kassel, Kassel, Germany (F.W.H.)
| | - Susan S Taylor
- Department of Pharmacology (D.J.R., N.A., J.S.G.), Department of Chemistry and Biochemistry (S.S.T.), and Moores Cancer Center (D.J.R., N.A., J.S.G.), University of California, San Diego, La Jolla, California; Laboratorio di Biologia Bio@SNS, Scuola Normale Superiore, Pisa, Italy (F.R.); and Department of Biochemistry, University of Kassel, Kassel, Germany (F.W.H.)
| | - J Silvio Gutkind
- Department of Pharmacology (D.J.R., N.A., J.S.G.), Department of Chemistry and Biochemistry (S.S.T.), and Moores Cancer Center (D.J.R., N.A., J.S.G.), University of California, San Diego, La Jolla, California; Laboratorio di Biologia Bio@SNS, Scuola Normale Superiore, Pisa, Italy (F.R.); and Department of Biochemistry, University of Kassel, Kassel, Germany (F.W.H.)
| |
Collapse
|
65
|
Does Differential Receptor Distribution Underlie Variable Responses to a Neuropeptide in the Lobster Cardiac System? Int J Mol Sci 2021; 22:ijms22168703. [PMID: 34445418 PMCID: PMC8395929 DOI: 10.3390/ijms22168703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/26/2021] [Accepted: 08/07/2021] [Indexed: 11/17/2022] Open
Abstract
Central pattern generators produce rhythmic behaviors independently of sensory input; however, their outputs can be modulated by neuropeptides, thereby allowing for functional flexibility. We investigated the effects of C-type allatostatins (AST-C) on the cardiac ganglion (CG), which is the central pattern generator that controls the heart of the American lobster, Homarus americanus, to identify the biological mechanism underlying the significant variability in individual responses to AST-C. We proposed that the presence of multiple receptors, and thus differential receptor distribution, was at least partly responsible for this observed variability. Using transcriptome mining and PCR-based cloning, we identified four AST-C receptors (ASTCRs) in the CG; we then characterized their cellular localization, binding potential, and functional activation. Only two of the four receptors, ASTCR1 and ASTCR2, were fully functional GPCRs that targeted to the cell surface and were activated by AST-C peptides in our insect cell expression system. All four, however, were amplified from CG cDNAs. Following the confirmation of ASTCR expression, we used physiological and bioinformatic techniques to correlate receptor expression with cardiac responses to AST-C across individuals. Expression of ASTCR1 in the CG showed a negative correlation with increasing contraction amplitude in response to AST-C perfusion through the lobster heart, suggesting that the differential expression of ASTCRs within the CG is partly responsible for the specific physiological response to AST-C exhibited by a given individual lobster.
Collapse
|
66
|
Sachdev S, Cabalteja CC, Cheloha RW. Strategies for targeting cell surface proteins using multivalent conjugates and chemical biology. Methods Cell Biol 2021; 166:205-222. [PMID: 34752333 PMCID: PMC8895325 DOI: 10.1016/bs.mcb.2021.06.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
Proper function of receptors on the cell surface is essential for homeostasis. Compounds that target cell surface receptors to address dysregulation have proven exceptionally successful as therapeutic agents; however, the development of compounds with the desired specificity for receptors, cells, and tissues of choice has proven difficult in some cases. The use of compounds that can engage more than one binding site at the cell surface offers a path toward improving biological specificity or pharmacological properties. In this chapter we summarize historical context for the development of such bivalent compounds. We focus on developments in chemical methods and biological engineering to provide bivalent compounds in which the high affinity and specificity of antibodies are leveraged to create multifunctional conjugates with new and useful properties. The development of methods to meld biological macromolecules with synthetic compounds will facilitate modulation of receptor biology in ways not previously possible.
Collapse
Affiliation(s)
- Shivani Sachdev
- National Institutes of Health, National Institute of Diabetes, Digestive, and Kidney Diseases (NIDDK), Laboratory of Bioorganic Chemistry, Bethesda, MD, United States
| | - Chino C Cabalteja
- National Institutes of Health, National Institute of Diabetes, Digestive, and Kidney Diseases (NIDDK), Laboratory of Bioorganic Chemistry, Bethesda, MD, United States
| | - Ross W Cheloha
- National Institutes of Health, National Institute of Diabetes, Digestive, and Kidney Diseases (NIDDK), Laboratory of Bioorganic Chemistry, Bethesda, MD, United States.
| |
Collapse
|
67
|
Herbrechter R, Hube N, Buchholz R, Reiner A. Splicing and editing of ionotropic glutamate receptors: a comprehensive analysis based on human RNA-Seq data. Cell Mol Life Sci 2021; 78:5605-5630. [PMID: 34100982 PMCID: PMC8257547 DOI: 10.1007/s00018-021-03865-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 05/12/2021] [Accepted: 05/22/2021] [Indexed: 12/11/2022]
Abstract
Ionotropic glutamate receptors (iGluRs) play key roles for signaling in the central nervous system. Alternative splicing and RNA editing are well-known mechanisms to increase iGluR diversity and to provide context-dependent regulation. Earlier work on isoform identification has focused on the analysis of cloned transcripts, mostly from rodents. We here set out to obtain a systematic overview of iGluR splicing and editing in human brain based on RNA-Seq data. Using data from two large-scale transcriptome studies, we established a workflow for the de novo identification and quantification of alternative splice and editing events. We detected all canonical iGluR splice junctions, assessed the abundance of alternative events described in the literature, and identified new splice events in AMPA, kainate, delta, and NMDA receptor subunits. Notable events include an abundant transcript encoding the GluA4 amino-terminal domain, GluA4-ATD, a novel C-terminal GluD1 (delta receptor 1) isoform, GluD1-b, and potentially new GluK4 and GluN2C isoforms. C-terminal GluN1 splicing may be controlled by inclusion of a cassette exon, which shows preference for one of the two acceptor sites in the last exon. Moreover, we identified alternative untranslated regions (UTRs) and species-specific differences in splicing. In contrast, editing in exonic iGluR regions appears to be mostly limited to ten previously described sites, two of which result in silent amino acid changes. Coupling of proximal editing/editing and editing/splice events occurs to variable degree. Overall, this analysis provides the first inventory of alternative splicing and editing in human brain iGluRs and provides the impetus for further transcriptome-based and functional investigations.
Collapse
Affiliation(s)
- Robin Herbrechter
- Department of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Nadine Hube
- Department of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Raoul Buchholz
- Department of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Andreas Reiner
- Department of Biology and Biotechnology, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany.
| |
Collapse
|
68
|
Torrens-Fontanals M, Stepniewski TM, Gloriam DE, Selent J. Structural dynamics bridge the gap between the genetic and functional levels of GPCRs. Curr Opin Struct Biol 2021; 69:150-159. [PMID: 34052782 DOI: 10.1016/j.sbi.2021.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/22/2021] [Accepted: 04/19/2021] [Indexed: 12/17/2022]
Abstract
G protein-coupled receptors (GPCRs) are implicated in nearly all physiological processes in the human body and represent an important drug targeting class. The genes encoding the different GPCR (sub)types determine their specific functionality, which can be altered by natural genetic variants and isoforms. Deciphering the molecular link between sequence diversity and its functional consequences is a current challenge and critical for the comprehension of the physiological response of GPCRs. It requires a global understanding of how protein sequence translates into protein structure, how this impacts the structural motions of the protein, and, finally, how all these factors determine the receptor functionality. Here, we discuss available resources and state-of-the-art computational approaches to address this question.
Collapse
Affiliation(s)
- Mariona Torrens-Fontanals
- Research Programme on Biomedical Informatics (GRIB), Hospital Del Mar Medical Research Institute (IMIM)-Department of Experimental and Health Sciences, Pompeu Fabra University (UPF), 08003 Barcelona, Spain
| | - Tomasz M Stepniewski
- Research Programme on Biomedical Informatics (GRIB), Hospital Del Mar Medical Research Institute (IMIM)-Department of Experimental and Health Sciences, Pompeu Fabra University (UPF), 08003 Barcelona, Spain; InterAx Biotech AG, PARK InnovAARE, 5234 Villigen, Switzerland; Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, 02-093 Warsaw, Poland
| | - David E Gloriam
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Jana Selent
- Research Programme on Biomedical Informatics (GRIB), Hospital Del Mar Medical Research Institute (IMIM)-Department of Experimental and Health Sciences, Pompeu Fabra University (UPF), 08003 Barcelona, Spain.
| |
Collapse
|
69
|
Jaschke N, Pählig S, Pan YX, Hofbauer LC, Göbel A, Rachner TD. From Pharmacology to Physiology: Endocrine Functions of μ-Opioid Receptor Networks. Trends Endocrinol Metab 2021; 32:306-319. [PMID: 33676828 PMCID: PMC8035298 DOI: 10.1016/j.tem.2021.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/08/2021] [Accepted: 02/11/2021] [Indexed: 01/04/2023]
Abstract
The steady rise in opioid users and abusers has uncovered multiple detrimental health consequences of perturbed opioid receptor signaling, thereby creating the need to better understand the biology of these systems. Among endogenous opioid networks, μ-receptors have received special attention due to their unprecedented biological complexity and broad implications in homeostatic functions. Here, we review the origin, molecular biology, and physiology of endogenous opioids with a special focus on μ-opioid receptor networks within the endocrine system. Moreover, we summarize the current evidence supporting an involvement of the latter in regulating distinct endocrine functions. Finally, we combine these insights to present an integrated perspective on μ-opioid receptor biology and provide an outlook on future studies and unresolved questions in this field.
Collapse
Affiliation(s)
- Nikolai Jaschke
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany.
| | - Sophie Pählig
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Ying-Xian Pan
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA
| | - Lorenz C Hofbauer
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Andy Göbel
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Tilman D Rachner
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| |
Collapse
|
70
|
Biased cytochrome P450-mediated metabolism via small-molecule ligands binding P450 oxidoreductase. Nat Commun 2021; 12:2260. [PMID: 33859207 PMCID: PMC8050233 DOI: 10.1038/s41467-021-22562-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 03/15/2021] [Indexed: 02/02/2023] Open
Abstract
Metabolic control is mediated by the dynamic assemblies and function of multiple redox enzymes. A key element in these assemblies, the P450 oxidoreductase (POR), donates electrons and selectively activates numerous (>50 in humans and >300 in plants) cytochromes P450 (CYPs) controlling metabolism of drugs, steroids and xenobiotics in humans and natural product biosynthesis in plants. The mechanisms underlying POR-mediated CYP metabolism remain poorly understood and to date no ligand binding has been described to regulate the specificity of POR. Here, using a combination of computational modeling and functional assays, we identify ligands that dock on POR and bias its specificity towards CYP redox partners, across mammal and plant kingdom. Single molecule FRET studies reveal ligand binding to alter POR conformational sampling, which results in biased activation of metabolic cascades in whole cell assays. We propose the model of biased metabolism, a mechanism akin to biased signaling of GPCRs, where ligand binding on POR stabilizes different conformational states that are linked to distinct metabolic outcomes. Biased metabolism may allow designing pathway-specific therapeutics or personalized food suppressing undesired, disease-related, metabolic pathways.
Collapse
|
71
|
Kooistra AJ, Mordalski S, Pándy-Szekeres G, Esguerra M, Mamyrbekov A, Munk C, Keserű GM, Gloriam D. GPCRdb in 2021: integrating GPCR sequence, structure and function. Nucleic Acids Res 2021; 49:D335-D343. [PMID: 33270898 PMCID: PMC7778909 DOI: 10.1093/nar/gkaa1080] [Citation(s) in RCA: 220] [Impact Index Per Article: 73.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 01/27/2023] Open
Abstract
G protein-coupled receptors (GPCRs) form both the largest family of membrane proteins and drug targets, mediating the action of one-third of medicines. The GPCR database, GPCRdb serves >4 000 researchers every month and offers reference data, analysis of own or literature data, experiment design and dissemination of published datasets. Here, we describe new and updated GPCRdb resources with a particular focus on integration of sequence, structure and function. GPCRdb contains all human non-olfactory GPCRs (and >27 000 orthologs), G-proteins and arrestins. It includes over 2 000 drug and in-trial agents and nearly 200 000 ligands with activity and availability data. GPCRdb annotates all published GPCR structures (updated monthly), which are also offered in a refined version (with re-modeled missing/distorted regions and reverted mutations) and provides structure models of all human non-olfactory receptors in inactive, intermediate and active states. Mutagenesis data in the GPCRdb spans natural genetic variants, GPCR-G protein interfaces, ligand sites and thermostabilising mutations. A new sequence signature tool for identification of functional residue determinants has been added and two data driven tools to design ligand site mutations and constructs for structure determination have been updated extending their coverage of receptors and modifications. The GPCRdb is available at https://gpcrdb.org.
Collapse
Affiliation(s)
- Albert J Kooistra
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Stefan Mordalski
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Gáspár Pándy-Szekeres
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
- Medicinal Chemistry Research Group, Research Center for Natural Sciences, Budapest H-1117, Hungary
| | - Mauricio Esguerra
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Alibek Mamyrbekov
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Christian Munk
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - György M Keserű
- Medicinal Chemistry Research Group, Research Center for Natural Sciences, Budapest H-1117, Hungary
| | - David E Gloriam
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| |
Collapse
|
72
|
Winfield I, Barkan K, Routledge S, Robertson NJ, Harris M, Jazayeri A, Simms J, Reynolds CA, Poyner DR, Ladds G. The Role of ICL1 and H8 in Class B1 GPCRs; Implications for Receptor Activation. Front Endocrinol (Lausanne) 2021; 12:792912. [PMID: 35095763 PMCID: PMC8796428 DOI: 10.3389/fendo.2021.792912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 12/15/2021] [Indexed: 11/13/2022] Open
Abstract
The first intracellular loop (ICL1) of G protein-coupled receptors (GPCRs) has received little attention, although there is evidence that, with the 8th helix (H8), it is involved in early conformational changes following receptor activation as well as contacting the G protein β subunit. In class B1 GPCRs, the distal part of ICL1 contains a conserved R12.48KLRCxR2.46b motif that extends into the base of the second transmembrane helix; this is weakly conserved as a [R/H]12.48KL[R/H] motif in class A GPCRs. In the current study, the role of ICL1 and H8 in signaling through cAMP, iCa2+ and ERK1/2 has been examined in two class B1 GPCRs, using mutagenesis and molecular dynamics. Mutations throughout ICL1 can either enhance or disrupt cAMP production by CGRP at the CGRP receptor. Alanine mutagenesis identified subtle differences with regard elevation of iCa2+, with the distal end of the loop being particularly sensitive. ERK1/2 activation displayed little sensitivity to ICL1 mutation. A broadly similar pattern was observed with the glucagon receptor, although there were differences in significance of individual residues. Extending the study revealed that at the CRF1 receptor, an insertion in ICL1 switched signaling bias between iCa2+ and cAMP. Molecular dynamics suggested that changes in ICL1 altered the conformation of ICL2 and the H8/TM7 junction (ICL4). For H8, alanine mutagenesis showed the importance of E3908.49b for all three signal transduction pathways, for the CGRP receptor, but mutations of other residues largely just altered ERK1/2 activation. Thus, ICL1 may modulate GPCR bias via interactions with ICL2, ICL4 and the Gβ subunit.
Collapse
MESH Headings
- Amino Acid Motifs/physiology
- Calcitonin Receptor-Like Protein/metabolism
- Calcitonin Receptor-Like Protein/physiology
- Calcitonin Receptor-Like Protein/ultrastructure
- Calcium Signaling
- Cyclic AMP/metabolism
- HEK293 Cells
- Humans
- MAP Kinase Signaling System
- Molecular Dynamics Simulation
- Protein Domains
- Protein Structure, Tertiary
- Receptor Activity-Modifying Protein 1/metabolism
- Receptor Activity-Modifying Protein 1/physiology
- Receptor Activity-Modifying Protein 1/ultrastructure
- Receptors, Calcitonin Gene-Related Peptide/metabolism
- Receptors, Calcitonin Gene-Related Peptide/physiology
- Receptors, Calcitonin Gene-Related Peptide/ultrastructure
- Receptors, Corticotropin-Releasing Hormone/metabolism
- Receptors, Corticotropin-Releasing Hormone/physiology
- Receptors, Corticotropin-Releasing Hormone/ultrastructure
- Receptors, G-Protein-Coupled
- Receptors, Glucagon/metabolism
- Receptors, Glucagon/physiology
- Receptors, Glucagon/ultrastructure
Collapse
Affiliation(s)
- Ian Winfield
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Kerry Barkan
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Sarah Routledge
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
- School of Life and Health Sciences, Aston University, Birmingham, United Kingdom
| | | | - Matthew Harris
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | | | - John Simms
- School of Life and Health Sciences, Aston University, Birmingham, United Kingdom
| | | | - David R. Poyner
- School of Life and Health Sciences, Aston University, Birmingham, United Kingdom
- *Correspondence: Graham Ladds, ; David R. Poyner,
| | - Graham Ladds
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
- *Correspondence: Graham Ladds, ; David R. Poyner,
| |
Collapse
|
73
|
Biased Ligands Differentially Shape the Conformation of the Extracellular Loop Region in 5-HT 2B Receptors. Int J Mol Sci 2020; 21:ijms21249728. [PMID: 33419260 PMCID: PMC7767279 DOI: 10.3390/ijms21249728] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 12/16/2020] [Accepted: 12/18/2020] [Indexed: 01/05/2023] Open
Abstract
G protein-coupled receptors are linked to various intracellular transducers, each pathway associated with different physiological effects. Biased ligands, capable of activating one pathway over another, are gaining attention for their therapeutic potential, as they could selectively activate beneficial pathways whilst avoiding those responsible for adverse effects. We performed molecular dynamics simulations with known β-arrestin-biased ligands like lysergic acid diethylamide and ergotamine in complex with the 5-HT2B receptor and discovered that the extent of ligand bias is directly connected with the degree of closure of the extracellular loop region. Given a loose allosteric coupling of extracellular and intracellular receptor regions, we delineate a concept for biased signaling at serotonin receptors, by which conformational interference with binding pocket closure restricts the signaling repertoire of the receptor. Molecular docking studies of biased ligands gathered from the BiasDB demonstrate that larger ligands only show plausible docking poses in the ergotamine-bound structure, highlighting the conformational constraints associated with bias. This emphasizes the importance of selecting the appropriate receptor conformation on which to base virtual screening workflows in structure-based drug design of biased ligands. As this mechanism of ligand bias has also been observed for muscarinic receptors, our studies provide a general mechanism of signaling bias transferable between aminergic receptors.
Collapse
|
74
|
van Gastel J, Leysen H, Boddaert J, Vangenechten L, Luttrell LM, Martin B, Maudsley S. Aging-related modifications to G protein-coupled receptor signaling diversity. Pharmacol Ther 2020; 223:107793. [PMID: 33316288 DOI: 10.1016/j.pharmthera.2020.107793] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/26/2020] [Indexed: 02/06/2023]
Abstract
Aging is a highly complex molecular process, affecting nearly all tissue systems in humans and is the highest risk factor in developing neurodegenerative disorders such as Alzheimer's and Parkinson's disease, cardiovascular disease and Type 2 diabetes mellitus. The intense complexity of the aging process creates an incentive to develop more specific drugs that attenuate or even reverse some of the features of premature aging. As our current pharmacopeia is dominated by therapeutics that target members of the G protein-coupled receptor (GPCR) superfamily it may be prudent to search for effective anti-aging therapeutics in this fertile domain. Since the first demonstration of GPCR-based β-arrestin signaling, it has become clear that an enhanced appreciation of GPCR signaling diversity may facilitate the creation of therapeutics with selective signaling activities. Such 'biased' ligand signaling profiles can be effectively investigated using both standard molecular biological techniques as well as high-dimensionality data analyses. Through a more nuanced appreciation of the quantitative nature across the multiple dimensions of signaling bias that drugs possess, researchers may be able to further refine the efficacy of GPCR modulators to impact the complex aberrations that constitute the aging process. Identifying novel effector profiles could expand the effective pharmacopeia and assist in the design of precision medicines. This review discusses potential non-G protein effectors, and specifically their potential therapeutic suitability in aging and age-related disorders.
Collapse
Affiliation(s)
- Jaana van Gastel
- Receptor Biology Lab, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium; Faculty of Pharmacy, Biomedical and Veterinary Science, University of Antwerp, Antwerp, Belgium
| | - Hanne Leysen
- Receptor Biology Lab, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium; Faculty of Pharmacy, Biomedical and Veterinary Science, University of Antwerp, Antwerp, Belgium
| | - Jan Boddaert
- Molecular Pathology Group, Faculty of Medicine and Health Sciences, Laboratory of Cell Biology and Histology, Antwerp, Belgium
| | - Laura Vangenechten
- Receptor Biology Lab, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Louis M Luttrell
- Division of Endocrinology, Diabetes & Medical Genetics, Medical University of South Carolina, USA
| | - Bronwen Martin
- Faculty of Pharmacy, Biomedical and Veterinary Science, University of Antwerp, Antwerp, Belgium
| | - Stuart Maudsley
- Receptor Biology Lab, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium; Faculty of Pharmacy, Biomedical and Veterinary Science, University of Antwerp, Antwerp, Belgium.
| |
Collapse
|
75
|
|