1
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Saito N, Toyoda M, Kondo M, Abe M, Sanechika N, Kimura M, Sawada K, Fukagawa M. Regulation of Renin Expression by Β1-Integrin in As4.1 Juxtaglomerular Line Cells. Biomedicines 2023; 11:biomedicines11020501. [PMID: 36831037 PMCID: PMC9953579 DOI: 10.3390/biomedicines11020501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 02/12/2023] Open
Abstract
(1) Background: Renal dysfunction and hypertension are mutually aggravating factors; however, the details of their interaction remain unclear. In a study using renal tissue from diabetic rats, we found that β1-integrin, a cell-substrate adhesion molecule, is specifically phosphorylated in juxtaglomerular cells that secrete renin, a blood pressure regulator. (2) Methods: A mouse juxtaglomerular cell line (As4.1 cells) was used for the following experiments: drug-induced promotion of β1-integrin phosphorylation/dephosphorylation; knockdown of β1-integrin and the cell adhesion molecule connexin-40 (a candidate for the main body of baroreceptor); and pressurization to atmospheric pressure + 100 mmHg. culture in hypotonic liquid medium. The expression of renin under these conditions was measured by qRT-PCR. (3) Results: Phosphorylation of β1-integrin suppressed the expression of renin, while dephosphorylation conversely promoted it. β1-integrin and connexin-40 knockdown both promoted the expression of renin. Pneumatic pressurization and hypotonic medium culture both decreased the expression of renin, which was restored by the knockdown of β1-integrin. (4) Conclusions: β1-integrin plays an inhibitory role in the regulation of the expression of renin, which may be controlled by phosphorylation and dephosphorylation. It is hypothesized that β1-integrin and other adhesion factors regulate the expression of renin by altering the sensitivity of baroreceptors on the plasma membrane.
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Affiliation(s)
| | - Masao Toyoda
- Correspondence: ; Tel.: +81-463-93-1121 (ext. 2490)
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2
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Akizuki K, Shimoda N, Ozaki H, Yamazaki T, Hirano T, Ishihara Y, Sueyoshi N, Kameshita I, Murai T, Ishida A. CaMK phosphatase (CaMKP/POPX2/PPM1F) inhibitors suppress the migration of human breast cancer MDA-MB-231 cells with loss of polarized morphology. Biochem Biophys Res Commun 2023; 639:1-8. [PMID: 36463756 DOI: 10.1016/j.bbrc.2022.11.064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/15/2022] [Accepted: 11/22/2022] [Indexed: 11/27/2022]
Abstract
CaMK phosphatase (CaMKP/POPX2/PPM1F) is a Ser/Thr protein phosphatase that belongs to the PPM family. Accumulating evidence suggests that CaMKP is involved in the pathogenesis of various diseases, including cancer. To clarify the relationship between CaMKP activity and human breast cancer cell motility, we examined the phosphatase activity of CaMKP in cell extracts. CaMKP activity assays of the immunoprecipitates prepared from the cell extract revealed that cells exhibiting higher motility had higher CaMKP activity, with no significant differences in the specific activity being observed. Two CaMKP-specific inhibitors, 1-amino-8-naphthol-4-sulfonic acid (ANS) and 1-amino-8-naphthol-2,4-disulfonic acid (ANDS), inhibited the migration of highly invasive MDA-MB-231 breast cancer cells without significant cytotoxicity, while an inactive analog, naphthionic acid, did not. Furthermore, the cells lost their elongated morphology and assumed a rounded shape following treatment with ANS, whereas they retained their elongated morphology following treatment with naphthionic acid. Consistent with these findings, ANS and ANDS significantly enhanced the phosphorylation level of CaMKI, a cellular substrate of CaMKP, while naphthionic acid did not. The present data suggest that CaMKP could be a novel therapeutic target for cancer metastasis.
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Affiliation(s)
- Kazutoshi Akizuki
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan
| | - Nao Shimoda
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan
| | - Hana Ozaki
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan
| | - Takeshi Yamazaki
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan
| | - Tetsuo Hirano
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan
| | - Yasuhiro Ishihara
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan
| | - Noriyuki Sueyoshi
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa, 761-0795, Japan
| | - Isamu Kameshita
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa, 761-0795, Japan
| | - Toshiyuki Murai
- Department of Microbiology and Immunology, Graduate School of Medicine, Osaka University, Suita, 565-0871, Japan.
| | - Atsuhiko Ishida
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan.
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3
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Matino L, Mariano A, Ausilio C, Garg R, Cohen-Karni T, Santoro F. Modulation of Early Stage Neuronal Outgrowth through Out-of-Plane Graphene. NANO LETTERS 2022; 22:8633-8640. [PMID: 36301701 DOI: 10.1021/acs.nanolett.2c03171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The correct wiring of a neural network requires neuron to integrate an incredible repertoire of cues found in their extracellular environment. The astonishing efficiency of this process plays a pivotal role in the correct wiring of the brain during development and axon regeneration. Biologically inspired micro- and nanostructured substrates have been shown to regulate axonal outgrowth. In parallel, several studies investigated graphene's potential as a conductive neural interface, able to enhance cell adhesion, neurite sprouting and outgrowth. Here, we engineered a 3D single- to few-layer fuzzy graphene morphology (3DFG), 3DFG on a collapsed Si nanowire (SiNW) mesh template (NT-3DFGc), and 3DFG on a noncollapsed SiNW mesh template (NT-3DFGnc) as neural-instructive materials. The micrometric protruding features of the NWs templates dictated neuronal growth cone establishment, as well as influencing axon elongation and branching. Furthermore, neurons-to-graphene coupling was investigated with comprehensive view of integrin-mediated contact adhesion points and plasma membrane curvature processes.
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Affiliation(s)
- Laura Matino
- Tissue Electronics, Istituto Italiano di Tecnologia, Naples 80125, Italy
- Dipartimento di Ingegneria Chimica, dei Materiali e delle Produzioni Industriali, DICMAPI, Università "Federico II", Naples 80125, Italy
| | - Anna Mariano
- Tissue Electronics, Istituto Italiano di Tecnologia, Naples 80125, Italy
| | - Chiara Ausilio
- Tissue Electronics, Istituto Italiano di Tecnologia, Naples 80125, Italy
| | - Raghav Garg
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Tzahi Cohen-Karni
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Francesca Santoro
- Tissue Electronics, Istituto Italiano di Tecnologia, Naples 80125, Italy
- Faculty of Electrical Engineering and IT, RWTH Aachen 52074, Germany
- Institute for Biological Information Processing-Bioelectronics, IBI-3, Forschungszentrum Juelich 52428, Germany
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4
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Goob G, Adrian J, Cossu C, Hauck CR. Phagocytosis mediated by the human granulocyte receptor CEACAM3 is limited by the receptor-type protein tyrosine phosphatase PTPRJ. J Biol Chem 2022; 298:102269. [PMID: 35850306 PMCID: PMC9418913 DOI: 10.1016/j.jbc.2022.102269] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 07/04/2022] [Accepted: 07/06/2022] [Indexed: 11/18/2022] Open
Abstract
Carcinoembryonic Antigen-related Cell Adhesion Molecule 3 (CEACAM3) is a human granulocyte receptor mediating the efficient phagocytosis of a subset of human-restricted bacterial pathogens. Its function depends on phosphorylation of a tyrosine-based sequence motif, but the enzyme(s) responsible for reversing this modification are unclear. Here, we identify the receptor-type protein tyrosine phosphatase PTPRJ as a negative regulator of CEACAM3-mediated phagocytosis. We show depletion of PTPRJ results in a gain-of-function phenotype, while overexpression of a constitutively active PTPRJ phosphatase strongly reduces bacterial uptake via CEACAM3. We also determined that recombinant PTPRJ directly dephosphorylates the cytoplasmic tyrosine residues of purified full-length CEACAM3 and recognizes synthetic CEACAM3-derived phospho-peptides as substrates. Dephosphorylation of CEACAM3 by PTPRJ is also observed in intact cells, thereby limiting receptor-initiated cytoskeletal re-arrangements, lamellipodia formation, and bacterial uptake. Finally, we show that human phagocytes deficient for PTPRJ exhibit exaggerated lamellipodia formation and enhanced opsonin-independent phagocytosis of CEACAM3-binding bacteria. Taken together, our results highlight PTPRJ as a bona fide negative regulator of CEACAM3-initiated phagocyte functions, revealing a potential molecular target to limit CEACAM3-driven inflammatory responses.
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Affiliation(s)
- Griseldis Goob
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Germany
| | - Jonas Adrian
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Germany
| | - Chiara Cossu
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Germany
| | - Christof R Hauck
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Germany; Konstanz Research School Chemical Biology, Universität Konstanz, Germany.
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5
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Gahmberg CG, Grönholm M, Madhavan S. Regulation of Dynamic Cell Adhesion by Integrin-Integrin Crosstalk. Cells 2022; 11:cells11101685. [PMID: 35626722 PMCID: PMC9140058 DOI: 10.3390/cells11101685] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/11/2022] [Accepted: 05/17/2022] [Indexed: 02/07/2023] Open
Abstract
Most cells express several integrins. The integrins are able to respond to various cellular functions and needs by modifying their own activation state, but in addition by their ability to regulate each other by activation or inhibition. This crosstalk or transdominant regulation is strictly controlled. The mechanisms resulting in integrin crosstalk are incompletely understood, but they often involve intracellular signalling routes also used by other cell surface receptors. Several studies show that the integrin cytoplasmic tails bind to a number of cytoskeletal and adaptor molecules in a regulated manner. Recent work has shown that phosphorylations of integrins and key intracellular molecules are of pivotal importance in integrin-cytoplasmic interactions, and these in turn affect integrin activity and crosstalk. The integrin β-chains play a central role in regulating crosstalk. In addition to Integrin-integrin crosstalk, crosstalk may also occur between integrins and related receptors, including other adhesion receptors, growth factor and SARS-CoV-2 receptors.
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Affiliation(s)
- Carl G. Gahmberg
- Molecular and Integrative Biosciences Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 9 C, 00014 Helsinki, Finland; (M.G.); (S.M.)
- Correspondence: ; Tel.: +358-50-539-9439
| | - Mikaela Grönholm
- Molecular and Integrative Biosciences Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 9 C, 00014 Helsinki, Finland; (M.G.); (S.M.)
- Drug Research Program, Faculty of Pharmacy, University of Helsinki, Viikinkaari 9 C, 00014 Helsinki, Finland
| | - Sudarrshan Madhavan
- Molecular and Integrative Biosciences Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 9 C, 00014 Helsinki, Finland; (M.G.); (S.M.)
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6
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Grimm TM, Herbinger M, Krüger L, Müller S, Mayer TU, Hauck CR. Lockdown, a selective small-molecule inhibitor of the integrin phosphatase PPM1F, blocks cancer cell invasion. Cell Chem Biol 2022; 29:930-946.e9. [PMID: 35443151 DOI: 10.1016/j.chembiol.2022.03.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 03/04/2022] [Accepted: 03/23/2022] [Indexed: 12/18/2022]
Abstract
Phosphatase PPM1F is a regulator of cell adhesion by fine-tuning integrin activity and actin cytoskeleton structures. Elevated expression of this enzyme in human tumors is associated with high invasiveness, enhanced metastasis, and poor prognosis. Thus, PPM1F is a target for pharmacological intervention, yet inhibitors of this enzyme are lacking. Here, we use high-throughput screening to identify Lockdown, a reversible and non-competitive PPM1F inhibitor. Lockdown is selective for PPM1F, because this compound does not inhibit other protein phosphatases in vitro and does not induce additional phenotypes in PPM1F knockout cells. Importantly, Lockdown-treated glioblastoma cells fully re-capitulate the phenotype of PPM1F-deficient cells as assessed by increased phosphorylation of PPM1F substrates and corruption of integrin-dependent cellular processes. Ester modification yields LockdownPro with increased membrane permeability and prodrug-like properties. LockdownPro suppresses tissue invasion by PPM1F-overexpressing human cancer cells, validating PPM1F as a therapeutic target and providing an access point to control tumor cell dissemination.
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Affiliation(s)
- Tanja M Grimm
- Lehrstuhl Zellbiologie, Department of Biology, University of Konstanz, Maildrop 621, Universitätsstrasse 10, 78467 Konstanz, Germany; Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrasse 10, 78467 Konstanz, Germany
| | - Marleen Herbinger
- Lehrstuhl Zellbiologie, Department of Biology, University of Konstanz, Maildrop 621, Universitätsstrasse 10, 78467 Konstanz, Germany
| | - Lena Krüger
- Department of Chemistry, University of Konstanz, Universitätsstrasse 10, 78467 Konstanz, Germany; Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrasse 10, 78467 Konstanz, Germany
| | - Silke Müller
- Lehrstuhl Molekulare Genetik, Department of Biology, University of Konstanz, Universitätsstrasse 10, 78467 Konstanz, Germany; Screening Center, Department of Biology, University of Konstanz, Universitätsstrasse 10, 78467 Konstanz, Germany
| | - Thomas U Mayer
- Lehrstuhl Molekulare Genetik, Department of Biology, University of Konstanz, Universitätsstrasse 10, 78467 Konstanz, Germany; Screening Center, Department of Biology, University of Konstanz, Universitätsstrasse 10, 78467 Konstanz, Germany; Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrasse 10, 78467 Konstanz, Germany
| | - Christof R Hauck
- Lehrstuhl Zellbiologie, Department of Biology, University of Konstanz, Maildrop 621, Universitätsstrasse 10, 78467 Konstanz, Germany; Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrasse 10, 78467 Konstanz, Germany.
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7
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Akizuki K, Ishikawa S, Obatake R, Ozaki H, Shimoda N, Nehira T, Yamazaki T, Kinumi T, Osawa J, Sueyoshi N, Kameshita I, Shigeri Y, Ishida A. CaM kinase phosphatase (CaMKP/PPM1F/POPX2) is specifically inactivated through gallate-mediated protein carbonylation. Arch Biochem Biophys 2022; 720:109170. [PMID: 35276214 DOI: 10.1016/j.abb.2022.109170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/23/2022] [Accepted: 02/28/2022] [Indexed: 11/24/2022]
Abstract
CaMK phosphatase (CaMKP/PPM1F/POPX2) is a Mn2+-dependent, calyculin A/okadaic acid-insensitive Ser/Thr protein phosphatase that belongs to the PPM family. CaMKP is thought to be involved in regulation of not only various protein kinases, such as CaM kinases and p21-activated protein kinase, but also of cellular proteins regulated by phosphorylation. A large-scale screening of a chemical library identified gallic acid and some of its alkyl esters as novel CaMKP inhibitors highly specific to CaMKP. Surprisingly, they caused specific carbonylation of CaMKP, leading to its inactivation. Under the same conditions, no carbonylation nor inactivation was observed when PPM1A, which is affiliated with the same family as CaMKP, and λ-phosphatase were used. The carbonylation reaction was inhibited by SH compounds such as cysteamine in a dose-dependent manner with a concomitant decrease in CaMKP inhibition by ethyl gallate. The pyrogallol structure of gallate was necessary for the gallate-mediated carbonylation of CaMKP. Point mutations of CaMKP leading to impairment of phosphatase activity did not significantly affect the gallate-mediated carbonylation. Ethyl gallate resulted in almost complete inhibition of CaMKP under the conditions where the carbonylation level was nearly identical to that of CaMKP carbonylation via metal-catalyzed oxidation with ascorbic acid/FeSO4, which resulted in only a partial inhibition of CaMKP. The gallate-mediated carbonylation of CaMKP absolutely required divalent cations such as Mn2+, Cu2+, Co2+ and Fe2+, and was markedly enhanced by a phosphopeptide substrate. When MDA-MB-231 cells transiently expressing CaM kinase I, a CaMKP substrate, were treated by ethyl gallate, significant enhancement of phosphorylation of CaM kinase I was observed, suggesting that ethyl gallate can penetrate into cells to inactivate cellular CaMKP. All the presented data strongly support the hypothesis that CaMKP undergoes carbonylation of its specific amino acid residues by incubation with alkyl gallates and the divalent metal cations, leading to inactivation specific to CaMKP.
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Affiliation(s)
- Kazutoshi Akizuki
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan
| | - Shun Ishikawa
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan
| | - Rika Obatake
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan
| | - Hana Ozaki
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan
| | - Nao Shimoda
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan
| | - Tatsuo Nehira
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan
| | - Takeshi Yamazaki
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan
| | - Tomoya Kinumi
- Bio-medical Standards Group, Research Institute for Material and Chemical Measurement, National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba C-3, Ibaraki, 305-8563, Japan
| | - Jin Osawa
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa, 761-0795, Japan
| | - Noriyuki Sueyoshi
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa, 761-0795, Japan
| | - Isamu Kameshita
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa, 761-0795, Japan
| | - Yasushi Shigeri
- Department of Chemistry, Wakayama Medical University, Wakayama, 641-0011, Japan.
| | - Atsuhiko Ishida
- Laboratory of Molecular Brain Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan.
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8
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Böttcher RT, Strohmeyer N, Aretz J, Fässler R. New insights into the phosphorylation of the threonine motif of the β1 integrin cytoplasmic domain. Life Sci Alliance 2022; 5:5/4/e202101301. [PMID: 34996844 PMCID: PMC8761493 DOI: 10.26508/lsa.202101301] [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: 11/17/2021] [Revised: 12/23/2021] [Accepted: 12/23/2021] [Indexed: 01/18/2023] Open
Abstract
Integrins require an activation step before ligand binding and signaling that is mediated by talin and kindlin binding to the β integrin cytosolic domain (β-tail). Conflicting reports exist about the contribution of phosphorylation of a conserved threonine motif in the β1-tail (β1-pT788/pT789) to integrin activation. We show that widely used and commercially available antibodies against β1-pT788/pT789 integrin do not detect specific β1-pT788/pT789 integrin signals in immunoblots of several human and mouse cell lysates but bind bi-phosphorylated threonine residues in numerous proteins, which were identified by mass spectrometry experiments. Furthermore, we found that fibroblasts and epithelial cells expressing the phospho-mimicking β1-TT788/789DD integrin failed to activate β1 integrins and displayed reduced integrin ligand binding, adhesion initiation and cell spreading. These cellular defects are specifically caused by the inability of kindlin to bind β1-tail polypeptides carrying a phosphorylated threonine motif or phospho-mimicking TT788/789DD substitutions. Our findings indicate that the double-threonine motif in β1-class integrins is not a major phosphorylation site but if phosphorylated would curb integrin function.
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Affiliation(s)
- Ralph T Böttcher
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Nico Strohmeyer
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule Zurich, Basel, Switzerland
| | - Jonas Aretz
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Reinhard Fässler
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, Martinsried, Germany
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9
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Elimination of negative feedback in TLR signalling allows rapid and hypersensitive detection of microbial contaminants. Sci Rep 2021; 11:24414. [PMID: 34952917 PMCID: PMC8709846 DOI: 10.1038/s41598-021-03618-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 11/24/2021] [Indexed: 11/17/2022] Open
Abstract
The exquisite specificity of Toll-like receptors (TLRs) to sense microbial molecular signatures is used as a powerful tool to pinpoint microbial contaminants. Various cellular systems, from native human blood cells to transfected cell lines exploit TLRs as pyrogen detectors in biological preparations. However, slow cellular responses and limited sensitivity have hampered the replacement of animal-based tests such as the rabbit pyrogen test or lipopolysaccharide detection by Limulus amoebocyte lysate. Here, we report a novel human cell-based approach to boost detection of microbial contaminants by TLR-expressing cells. By genetic and pharmacologic elimination of negative control circuits, TLR-initiated cellular responses to bacterial molecular patterns were accelerated and significantly elevated. Combining depletion of protein phosphatase PP2ACA and pharmacological inhibition of PP1 in the optimized reporter cells further enhanced the sensitivity to allow detection of bacterial lipoprotein at 30 picogram/ml. Such next-generation cellular monitoring is poised to replace animal-based testing for microbial contaminants.
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10
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Gahmberg CG, Grönholm M. How integrin phosphorylations regulate cell adhesion and signaling. Trends Biochem Sci 2021; 47:265-278. [PMID: 34872819 PMCID: PMC8642147 DOI: 10.1016/j.tibs.2021.11.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/08/2021] [Accepted: 11/08/2021] [Indexed: 12/13/2022]
Abstract
Cell adhesion is essential for the formation of organs, cellular migration, and interaction with target cells and the extracellular matrix. Integrins are large protein α/β-chain heterodimers and form a major family of cell adhesion molecules. Recent research has dramatically increased our knowledge of how integrin phosphorylations regulate integrin activity. Phosphorylations determine the signaling complexes formed on the cytoplasmic tails, regulating downstream signaling. α-Chain phosphorylation is necessary for inducing β-chain phosphorylation in LFA-1, and the crosstalk from one integrin to another activating or inactivating its function is in part mediated by phosphorylation of β-chains. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus receptor angiotensin-converting enzyme 2 (ACE2) and possible integrin coreceptors may crosstalk and induce a phosphorylation switch and autophagy.
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Affiliation(s)
- Carl G Gahmberg
- Molecular and Integrative Biosciences Research Programme, University of Helsinki, Viikinkaari 9 C, 00014 Helsinki, Finland.
| | - Mikaela Grönholm
- Molecular and Integrative Biosciences Research Programme, University of Helsinki, Viikinkaari 9 C, 00014 Helsinki, Finland; Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E, 00014 Helsinki, Finland
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11
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Restoration of aged hematopoietic cells by their young counterparts through instructive microvesicles release. Aging (Albany NY) 2021; 13:23981-24016. [PMID: 34762598 PMCID: PMC8610119 DOI: 10.18632/aging.203689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 10/26/2021] [Indexed: 12/14/2022]
Abstract
This study addresses the potential to reverse age-associated morbidity by establishing methods to restore the aged hematopoietic system. Parabiotic animal models indicated that young secretome could restore aged tissues, leading us to establish a heterochronic transwell system with aged mobilized peripheral blood (MPB), co-cultured with young MPB or umbilical cord blood (UCB) cells. Functional studies and omics approaches indicate that the miRNA cargo of microvesicles (MVs) restores the aged hematopoietic system. The in vitro findings were validated in immune deficient (NSG) mice carrying an aged hematopoietic system, improving aged hallmarks such as increased lymphoid:myeloid ratio, decreased inflammation and cellular senescence. Elevated MYC and E2F pathways, and decreased p53 were key to hematopoietic restoration. These processes require four restorative miRs that target the genes for transcription/differentiation, namely PAX and phosphatase PPMIF. These miRs when introduced in aged cells were sufficient to restore the aged hematopoietic system in NSG mice. The aged MPBs were the drivers of their own restoration, as evidenced by the changes from distinct baseline miR profiles in MPBs and UCB to comparable expressions after exposure to aged MPBs. Restorative natural killer cells eliminated dormant breast cancer cells in vivo, indicating the broad relevance of this cellular paradigm - preventing and reversing age-associated disorders such as clearance of early malignancies and enhanced responses to vaccine and infection.
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12
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Seumen CHT, Grimm TM, Hauck CR. Protein phosphatases in TLR signaling. Cell Commun Signal 2021; 19:45. [PMID: 33882943 PMCID: PMC8058998 DOI: 10.1186/s12964-021-00722-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/10/2021] [Indexed: 02/06/2023] Open
Abstract
Toll-like receptors (TLRs) are critical sensors for the detection of potentially harmful microbes. They are instrumental in initiating innate and adaptive immune responses against pathogenic organisms. However, exaggerated activation of TLR receptor signaling can also be responsible for the onset of autoimmune and inflammatory diseases. While positive regulators of TLR signaling, such as protein serine/threonine kinases, have been studied intensively, only little is known about phosphatases, which counterbalance and limit TLR signaling. In this review, we summarize protein phosphorylation events and their roles in the TLR pathway and highlight the involvement of protein phosphatases as negative regulators at specific steps along the TLR-initiated signaling cascade. Then, we focus on individual phosphatase families, specify the function of individual enzymes in TLR signaling in more detail and give perspectives for future research. A better understanding of phosphatase-mediated regulation of TLR signaling could provide novel access points to mitigate excessive immune activation and to modulate innate immune signaling.![]() Video Abstract
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Affiliation(s)
- Clovis H T Seumen
- Lehrstuhl Zellbiologie, Universität Konstanz, Universitätsstraße 10, Postablage 621, 78457, Konstanz, Germany
| | - Tanja M Grimm
- Lehrstuhl Zellbiologie, Universität Konstanz, Universitätsstraße 10, Postablage 621, 78457, Konstanz, Germany.,Konstanz Research School Chemical Biology, Universität Konstanz, 78457, Konstanz, Germany
| | - Christof R Hauck
- Lehrstuhl Zellbiologie, Universität Konstanz, Universitätsstraße 10, Postablage 621, 78457, Konstanz, Germany. .,Konstanz Research School Chemical Biology, Universität Konstanz, 78457, Konstanz, Germany.
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