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Theofilas P, Wang C, Butler D, Morales DO, Petersen C, Ambrose A, Chin B, Yang T, Khan S, Ng R, Kayed R, Karch CM, Miller BL, Gestwicki JE, Gan L, Temple S, Arkin MR, Grinberg LT. iPSC-induced neurons with the V337M MAPT mutation are selectively vulnerable to caspase-mediated cleavage of tau and apoptotic cell death. Mol Cell Neurosci 2024; 130:103954. [PMID: 39032719 DOI: 10.1016/j.mcn.2024.103954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 07/09/2024] [Accepted: 07/10/2024] [Indexed: 07/23/2024] Open
Abstract
BACKGROUND Tau post-translational modifications (PTMs) result in the gradual build-up of abnormal tau and neuronal degeneration in tauopathies, encompassing variants of frontotemporal lobar degeneration (FTLD) and Alzheimer's disease (AD). Tau proteolytically cleaved by active caspases, including caspase-6, may be neurotoxic and prone to self-aggregation. Also, our recent findings show that caspase-6 truncated tau represents a frequent and understudied aspect of tau pathology in AD in addition to phospho-tau pathology. In AD and Pick's disease, a large percentage of caspase-6 associated cleaved-tau positive neurons lack phospho-tau, suggesting that many vulnerable neurons to tau pathology go undetected when using conventional phospho-tau antibodies and possibly will not respond to phospho-tau based therapies. Therefore, therapeutic strategies against caspase cleaved-tau pathology could be necessary to modulate the extent of tau abnormalities in AD and other tauopathies. METHODS To understand the timing and progression of caspase activation, tau cleavage, and neuronal death, we created two mAbs targeting caspase-6 tau cleavage sites and probed postmortem brain tissue from an individual with FTLD due to the V337M MAPT mutation. We then assessed tau cleavage and apoptotic stress response in cortical neurons derived from induced pluripotent stem cells (iPSCs) carrying the FTD-related V337M MAPT mutation. Finally, we evaluated the neuroprotective effects of caspase inhibitors in these iPSC-derived neurons. RESULTS FTLD V337M MAPT postmortem brain showed positivity for both cleaved tau mAbs and active caspase-6. Relative to isogenic wild-type MAPT controls, V337M MAPT neurons cultured for 3 months post-differentiation showed a time-dependent increase in pathogenic tau in the form of caspase-cleaved tau, phospho-tau, and higher levels of tau oligomers. Accumulation of toxic tau species in V337M MAPT neurons was correlated with increased vulnerability to pro-apoptotic stress. Notably, this mutation-associated cell death was pharmacologically rescued by the inhibition of effector caspases. CONCLUSIONS Our results suggest an upstream, time-dependent accumulation of caspase-6 cleaved tau in V337M MAPT neurons promoting neurotoxicity. These processes can be reversed by caspase inhibition. These results underscore the potential of developing caspase-6 inhibitors as therapeutic agents for FTLD and other tauopathies. Additionally, they highlight the promise of using caspase-cleaved tau as biomarkers for these conditions.
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Affiliation(s)
- Panos Theofilas
- Memory and Aging Center, Department of Neurology, UCSF, San Francisco, CA, USA
| | - Chao Wang
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
| | | | - Dulce O Morales
- Memory and Aging Center, Department of Neurology, UCSF, San Francisco, CA, USA
| | - Cathrine Petersen
- Memory and Aging Center, Department of Neurology, UCSF, San Francisco, CA, USA
| | - Andrew Ambrose
- Department of Pharmaceutical Chemistry and Small Molecule Discovery Center, UCSF, San Francisco, CA, USA
| | | | | | - Shireen Khan
- ChemPartner San Francisco, South San Francisco, CA, USA
| | - Raymond Ng
- ChemPartner San Francisco, South San Francisco, CA, USA
| | - Rakez Kayed
- Department of Neurology, University of Texas Medical Branch, Galveston, TX, USA
| | | | - Bruce L Miller
- Memory and Aging Center, Department of Neurology, UCSF, San Francisco, CA, USA
| | - Jason E Gestwicki
- Department of Pharmaceutical Chemistry, UCSF, San Francisco, CA, USA
| | - Li Gan
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA; Helen and Robert Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | | | - Michelle R Arkin
- Department of Pharmaceutical Chemistry and Small Molecule Discovery Center, UCSF, San Francisco, CA, USA.
| | - Lea T Grinberg
- Memory and Aging Center, Department of Neurology, UCSF, San Francisco, CA, USA; Department of Pathology, University of Sao Paulo Medical School, Brazil.
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Van Horn KS, Wang D, Medina-Cleghorn D, Lee PS, Bryant C, Altobelli C, Jaishankar P, Leung KK, Ng RA, Ambrose AJ, Tang Y, Arkin MR, Renslo AR. Engaging a Non-catalytic Cysteine Residue Drives Potent and Selective Inhibition of Caspase-6. J Am Chem Soc 2023; 145:10015-10021. [PMID: 37104712 PMCID: PMC10176470 DOI: 10.1021/jacs.2c12240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Indexed: 04/29/2023]
Abstract
Caspases are a family of cysteine-dependent proteases with important cellular functions in inflammation and apoptosis, while also implicated in human diseases. Classical chemical tools to study caspase functions lack selectivity for specific caspase family members due to highly conserved active sites and catalytic machinery. To overcome this limitation, we targeted a non-catalytic cysteine residue (C264) unique to caspase-6 (C6), an enigmatic and understudied caspase isoform. Starting from disulfide ligands identified in a cysteine trapping screen, we used a structure-informed covalent ligand design to produce potent, irreversible inhibitors (3a) and chemoproteomic probes (13-t) of C6 that exhibit unprecedented selectivity over other caspase family members and high proteome selectivity. This approach and the new tools described will enable rigorous interrogation of the role of caspase-6 in developmental biology and in inflammatory and neurodegenerative diseases.
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Affiliation(s)
- Kurt S. Van Horn
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, 600 16th Street, San Francisco, California 94143, United States
| | - Dongju Wang
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, 600 16th Street, San Francisco, California 94143, United States
- School
of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Daniel Medina-Cleghorn
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, 600 16th Street, San Francisco, California 94143, United States
| | - Peter S. Lee
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, 600 16th Street, San Francisco, California 94143, United States
| | - Clifford Bryant
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, 600 16th Street, San Francisco, California 94143, United States
| | - Chad Altobelli
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, 600 16th Street, San Francisco, California 94143, United States
| | - Priyadarshini Jaishankar
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, 600 16th Street, San Francisco, California 94143, United States
| | - Kevin K. Leung
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, 600 16th Street, San Francisco, California 94143, United States
| | - Raymond A. Ng
- Chempartner
Corporation, 280 Utah
Avenue, South San Francisco, California 94080, United States
| | - Andrew J. Ambrose
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, 600 16th Street, San Francisco, California 94143, United States
| | - Yinyan Tang
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, 600 16th Street, San Francisco, California 94143, United States
| | - Michelle R. Arkin
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, 600 16th Street, San Francisco, California 94143, United States
| | - Adam R. Renslo
- Department
of Pharmaceutical Chemistry, University
of California, San Francisco, 600 16th Street, San Francisco, California 94143, United States
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Jeong YE, Rajbhandari L, Kim BW, Venkatesan A, Hoke A. Downregulation of SF3B2 protects CNS neurons in models of multiple sclerosis. Ann Clin Transl Neurol 2023; 10:246-265. [PMID: 36574260 PMCID: PMC9930435 DOI: 10.1002/acn3.51717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/21/2022] [Accepted: 11/21/2022] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVE Neurodegeneration induced by inflammatory stress in multiple sclerosis (MS) leads to long-term neurological disabilities that are not amenable to current immunomodulatory therapies. METHODS AND RESULTS Here, we report that neuronal downregulation of Splicing factor 3b subunit 2 (SF3B2), a component of U2 small nuclear ribonucleoprotein (snRNP), preserves retinal ganglion cell (RGC) survival and axonal integrity in experimental autoimmune encephalomyelitis (EAE)-induced mice. By employing an in vitro system recapitulating the inflammatory environment of MS lesion, we show that when SF3B2 levels are downregulated, cell viability and axon integrity are preserved in cortical neurons against inflammatory toxicity. Notably, knockdown of SF3B2 suppresses the expression of injury-response and necroptosis genes and prevents activation of Sterile Alpha and TIR Motif Containing 1 (Sarm1), a key enzyme that mediates programmed axon degeneration. INTERPRETATION Together, these findings suggest that the downregulation of SF3B2 is a novel potential therapeutic target to prevent secondary neurodegeneration in MS.
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Affiliation(s)
- Ye Eun Jeong
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA
| | - Labchan Rajbhandari
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA
| | - Byung Woo Kim
- Division of Neuropathology, Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA
| | - Arun Venkatesan
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA
| | - Ahmet Hoke
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA
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4
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Yun J, Hansen S, Morris O, Madden DT, Libeu CP, Kumar AJ, Wehrfritz C, Nile AH, Zhang Y, Zhou L, Liang Y, Modrusan Z, Chen MB, Overall CC, Garfield D, Campisi J, Schilling B, Hannoush RN, Jasper H. Senescent cells perturb intestinal stem cell differentiation through Ptk7 induced noncanonical Wnt and YAP signaling. Nat Commun 2023; 14:156. [PMID: 36631445 PMCID: PMC9834240 DOI: 10.1038/s41467-022-35487-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 12/06/2022] [Indexed: 01/13/2023] Open
Abstract
Cellular senescence and the senescence-associated secretory phenotype (SASP) are implicated in aging and age-related disease, and SASP-related inflammation is thought to contribute to tissue dysfunction in aging and diseased animals. However, whether and how SASP factors influence the regenerative capacity of tissues remains unclear. Here, using intestinal organoids as a model of tissue regeneration, we show that SASP factors released by senescent fibroblasts deregulate stem cell activity and differentiation and ultimately impair crypt formation. We identify the secreted N-terminal domain of Ptk7 as a key component of the SASP that activates non-canonical Wnt / Ca2+ signaling through FZD7 in intestinal stem cells (ISCs). Changes in cytosolic [Ca2+] elicited by Ptk7 promote nuclear translocation of YAP and induce expression of YAP/TEAD target genes, impairing symmetry breaking and stem cell differentiation. Our study discovers secreted Ptk7 as a factor released by senescent cells and provides insight into the mechanism by which cellular senescence contributes to tissue dysfunction in aging and disease.
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Affiliation(s)
- Jina Yun
- Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Simon Hansen
- NBE Therapeutics, Hochbergstrasse 60C, 4057, Basel, Switzerland
| | - Otto Morris
- Exscientia Ltd., The Schrödinger Building Oxford Science Park, Oxford, OX4 4GE, UK
| | - David T Madden
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94945, USA
| | - Clare Peters Libeu
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94945, USA
| | - Arjun J Kumar
- Fred Hutch/University of Washington, 1100 Fairview Ave. N., Seattle, WA, 98109, USA
| | - Cameron Wehrfritz
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94945, USA
| | - Aaron H Nile
- Calico Labs LLC., 1170 Veterans Blvd, South San Francisco, CA, 94080, USA
| | - Yingnan Zhang
- Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Lijuan Zhou
- Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Yuxin Liang
- Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Zora Modrusan
- Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Michelle B Chen
- Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | | | - David Garfield
- Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Judith Campisi
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94945, USA
| | - Birgit Schilling
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94945, USA
| | - Rami N Hannoush
- Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA.
| | - Heinrich Jasper
- Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA.
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, 94945, USA.
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5
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The Formation of Melanocyte Apoptotic Bodies in Vitiligo and the Relocation of Vitiligo Autoantigens under Oxidative Stress. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:7617839. [PMID: 34745423 PMCID: PMC8568525 DOI: 10.1155/2021/7617839] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/24/2021] [Accepted: 09/27/2021] [Indexed: 11/17/2022]
Abstract
Background Oxidative stress has a vital role in the early stages of vitiligo. Autoantigens released from apoptotic melanocytes (MC) under oxidative stress are involved in the presentation and recognition of antigens. However, the transport of autoantigens to the cell surface and their release to the extracellular environment are still unclear. Apoptotic bodies (ABs) have always been considered as a key source of immunomodulators and autoantigens. Yet, the role of ABs in the immune mechanism of vitiligo is still unknown. Purpose To explore whether MC's autoantigens translocate into ABs during oxidative stress-induced apoptosis and study the molecular mechanisms underlying autoantigen migration and AB formation. Methods PIG3V (an immortalized human vitiligo melanocyte cell line) were treated with H2O2, and ABs were separated. Transmission electron microscopy, flow cytometry, Western blot, mass spectrometry, and other methods were used to determine the relocation of specific antigens in PIG3V cells to ABs. After pretreatment with specific inhibitors (Rho kinase (Y-27632), myosin light chain kinase (MLCK, ML-9), pan-caspase (zVAD-FMK), and JNK (SP600125)), the pathway of autoantigen translocation into ABs and the formation of apoptotic bodies were determined. Results When treated with 0.8 mM H2O2, ABs were released from these cells. Autoantigens such as tyrosinase-related protein 1 (TYRP-1) and cleavage nuclear membrane antigen Lamin A/C (Asp230) were concentrated in ABs. The expression of autoantigens and the formation of ABs increased in a time- and dose-dependent manner after treatment with H2O2, while the application of specific inhibitors inhibited the formation of apoptotic bodies, i.e., the expression of antigens. Conclusion Vitiligo autoantigens translocate into ABs in the process of apoptosis induced by oxidative stress. The cytoskeletal protein activation pathway and the JNK-related apoptosis pathway are involved in the transport of autoantigens and the formation of ABs. ABs may be the key bridge between MC cell apoptosis and cellular immunity.
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6
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Capo-Chichi CD, Cai KQ, Xu XX. Overexpression and cytoplasmic localization of caspase-6 is associated with lamin A degradation in set of ovarian cancers. Biomark Res 2018; 6:30. [PMID: 30450209 PMCID: PMC6208109 DOI: 10.1186/s40364-018-0144-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/24/2018] [Indexed: 01/18/2023] Open
Abstract
Background In most women with ovarian cancer, the diagnosis occurs after dissemination of tumor cells beyond ovaries. Several molecular perturbations occur ahead of tumor initiation including loss of lamin A/C. Our hypothesis was that the loss of nuclear structural proteins A type lamins (lamin A/C) transcribed from LMNA gene and substrate for active caspase-6 maybe one of the molecular perturbations. Our objective is to investigate the association between the loss of lamin A/C and the overexpression of caspase-6 in ovarian cancer cells. Method Western blotting and immunofluorescence were used to analyze the expression of lamin A/C and active caspase-6 in normal human ovarian surface epithelial (HOSE) cells, immortalized human ovarian surface epithelial cells and a set of seven ovarian cancer cell lines (including OVCAR3, OVCAR5, and A2780). The activity of caspase-6 was measured by densitometry, fluorescence and flow cytometry. Immunohistochemistry was used to evaluate the expression of caspase-6 in set of ovarian cancer tissues previously reported to have lost lamin A/C. Results The results showed that HOSE cells expressed lamin A/C and no or low level of active caspase-6 while cancer cells highly expressed caspase-6 and no or low level of lamin A/C. The inhibition of caspase-6 activity in OVCAR3 cells increased lamin A but has no effect on lamin C; active caspase-6 was localized in the cytoplasm associated with the loss of lamin A. Conclusion Overexpression and cytoplasmic localization of caspase-6 in ovarian cancer cells may be involved in lamin A degradation and deficiency observed in some ovarian cancer cells.
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Affiliation(s)
- Callinice D Capo-Chichi
- 1Institute of Applied Biomedical Sciences (ISBA), Unit of Biochemistry and Molecular Biology, Division of Molecular Biomarkers in Cancer and Nutrition, University of Abomey-Calavi, Abomey-Calavi, Benin.,2Sylvester Cancer Center (SCCC), Ovarian Cancer Program, University of Miami, Miami, Florida USA
| | - Kathy Q Cai
- 3Department of Pathology, Fox Chase Cancer Center, Philadelphia, PA USA
| | - Xiang-Xi Xu
- 2Sylvester Cancer Center (SCCC), Ovarian Cancer Program, University of Miami, Miami, Florida USA
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7
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Comparison of in vitro methods for carboxylesterase activity determination in immortalized cells representative of the intestine, liver and kidney. Mol Cell Probes 2015; 29:215-22. [DOI: 10.1016/j.mcp.2015.05.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 04/17/2015] [Accepted: 05/04/2015] [Indexed: 12/24/2022]
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8
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Wazir U, Orakzai MMAW, Khanzada ZS, Jiang WG, Sharma AK, Kasem A, Mokbel K. The role of death-associated protein 3 in apoptosis, anoikis and human cancer. Cancer Cell Int 2015; 15:39. [PMID: 25883535 PMCID: PMC4399419 DOI: 10.1186/s12935-015-0187-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 03/18/2015] [Indexed: 01/12/2023] Open
Abstract
Death-associated protein 3 (DAP3) is a molecule with a significant role in the control of both apoptosis and anoikis. Apoptosis is the predominant type of programmed cell death (PCD) which may occur in response to irreparable damage to DNA, or in response to induction by inflammatory cells. Anoikis is subset of apoptosis which occurs in epithelial cells in response to detachment from the surrounding matrix. Both apoptosis and anoikis are of interest in the context of carcinogenesis. In this review, we shall discuss apoptosis and anoikis, and the recent literature regarding the role of DAP3 in both these pathways.
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Affiliation(s)
- Umar Wazir
- />The London Breast Institute, Princess Grace Hospital, London, UK
- />Department of Breast Surgery, St. George’s Hospital and Medical School, University of London, London, UK
| | | | - Zubair S Khanzada
- />Metastasis and Angiogenesis Research Group, University Department of Surgery, Cardiff University School of Medicine, Cardiff University, Cardiff, Wales UK
| | - Wen G Jiang
- />Metastasis and Angiogenesis Research Group, University Department of Surgery, Cardiff University School of Medicine, Cardiff University, Cardiff, Wales UK
| | - Anup K Sharma
- />Department of Breast Surgery, St. George’s Hospital and Medical School, University of London, London, UK
| | - Abdul Kasem
- />The London Breast Institute, Princess Grace Hospital, London, UK
| | - Kefah Mokbel
- />The London Breast Institute, Princess Grace Hospital, London, UK
- />Department of Breast Surgery, St. George’s Hospital and Medical School, University of London, London, UK
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9
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Baburamani AA, Miyakuni Y, Vontell R, Supramaniam VG, Svedin P, Rutherford M, Gressens P, Mallard C, Takeda S, Thornton C, Hagberg H. Does Caspase-6 Have a Role in Perinatal Brain Injury? Dev Neurosci 2015; 37:321-37. [PMID: 25823427 PMCID: PMC4876595 DOI: 10.1159/000375368] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 01/19/2015] [Indexed: 12/31/2022] Open
Abstract
Apoptotic mechanisms are centre stage for the development of injury in the immature brain, and caspases have been shown to play a pivotal role during brain development and in response to injury. The inhibition of caspases using broad-spectrum agents such as Q-VD-OPh is neuroprotective in the immature brain. Caspase-6, an effector caspase, has been widely researched in neurodevelopmental disorders and found to be important following adult stroke, but its function in the neonatal brain has yet to be detailed. Furthermore, caspases may be important in microglial activation; microglia are required for optimal brain development and following injury, and their close involvement during neuronal cell death suggests that apoptotic cues such as caspase activation may be important in microglial activation. Therefore, in this study we aimed to investigate the possible apoptotic and non-apoptotic functions caspase-6 may have in the immature brain in response to hypoxia-ischaemia. We examined whether caspases are involved in microglial activation. We assessed cleaved caspase-6 expression following hypoxia-ischaemia and conducted primary microglial cultures to assess whether the broad-spectrum inhibitor Q-VD-OPh or caspase-6 gene deletion affected lipopolysaccharide (LPS)-mediated microglial activation and phenotype. We observed cleaved caspase-6 expression to be low but present in the cell body and cell processes in both a human case of white matter injury and 72 h following hypoxia-ischaemia in the rat. Gene deletion of caspase-6 did not affect the outcome of brain injury following mild (50 min) or severe (60 min) hypoxia-ischaemia. Interestingly, we did note that cleaved caspase-6 was co-localised with microglia that were not of apoptotic morphology. We observed that mRNA of a number of caspases was modulated by low-dose LPS stimulation of primary microglia. Q-VD-OPh treatment and caspase-6 gene deletion did not affect microglial activation but modified slightly the M2b phenotype response by changing the time course of SOCS3 expression after LPS administration. Our results suggest that the impact of active caspase-6 in the developing brain is subtle, and we believe there are predominantly other caspases (caspase-2, −3, −8, −9) that are essential for the cell death processes in the immature brain.
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Affiliation(s)
- Ana A Baburamani
- Perinatal Center, Institute of Neuroscience and Physiology, Department of Obstetrics and Gynecology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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10
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Fan H, Kou J, Han D, Li P, Zhang D, Wu Q, He Q. Sensitive proteolysis assay based on the detection of a highly characteristic solid-state process. RSC Adv 2015. [DOI: 10.1039/c5ra05749c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This paper reported a sensitive proteolysis assay based on the detection of a highly characteristic solid-state process.
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Affiliation(s)
- Hua Fan
- Department of Hepatobiliary Surgery
- Beijing Chaoyang Hospital
- Capital Medical University
- Beijing
- P. R. China
| | - Jiantao Kou
- Department of Hepatobiliary Surgery
- Beijing Chaoyang Hospital
- Capital Medical University
- Beijing
- P. R. China
| | - Dongdong Han
- Department of Hepatobiliary Surgery
- Beijing Chaoyang Hospital
- Capital Medical University
- Beijing
- P. R. China
| | - Ping Li
- Department of Hepatobiliary Surgery
- Beijing Chaoyang Hospital
- Capital Medical University
- Beijing
- P. R. China
| | - Dong Zhang
- Department of Hepatobiliary Surgery
- Beijing Chaoyang Hospital
- Capital Medical University
- Beijing
- P. R. China
| | - Qiao Wu
- Department of Hepatobiliary Surgery
- Beijing Chaoyang Hospital
- Capital Medical University
- Beijing
- P. R. China
| | - Qiang He
- Department of Hepatobiliary Surgery
- Beijing Chaoyang Hospital
- Capital Medical University
- Beijing
- P. R. China
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11
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Soares AS, Costa VM, Diniz C, Fresco P. Combination of Cl‑IB‑MECA with paclitaxel is a highly effective cytotoxic therapy causing mTOR‑dependent autophagy and mitotic catastrophe on human melanoma cells. J Cancer Res Clin Oncol 2014; 140:921-35. [PMID: 24659394 DOI: 10.1007/s00432-014-1645-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 03/07/2014] [Indexed: 02/07/2023]
Abstract
PURPOSE Metastatic melanoma is the deadliest form of skin cancer. It is highly resistant to conventional therapies,particularly to drugs that cause apoptosis as the main anticancer mechanism. Recently, induction of autophagic cell death is emerging as a novel therapeutic target for apoptotic-resistant cancers. We aimed to investigate the underlying mechanisms elicited by the cytotoxic combination of 2-chloro-N(6)-(3-iodobenzyl)-adenosine-5′-N-methyluronamide(Cl-IB-MECA, a selective A(3) adenosine receptor agonist; 10 μM) and paclitaxel (10 ng/mL) on human C32 and A375 melanoma cell lines. METHODS Cytotoxicity was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide reduction, neutral red uptake, and lactate dehydrogenase leakage assays, after 48-h incubation. Autophagosome and autolysosome formation was detected by fluorescence through monodansylcadaverine-staining and CellLight(®) Lysosomes-RFP-labelling, respectively. Cell nuclei were visualized by Hoechst staining, while levels of p62 were determined by an ELISA kit. Levels of mammalian target of rapamycin (mTOR) and the alterations of microtubule networks were evaluated by immunofluorescence. RESULTS We demonstrated, for the first time, that the combination of Cl-IB-MECA with paclitaxel significantly increases cytotoxicity, with apoptosis and autophagy the major mechanisms involved in cell death. Induction of autophagy, using clinically relevant doses,was confirmed by visualization of autophagosome and autolysosome formation, and downregulation of mTOR and p62 levels. Caspase-dependent and caspase-independent mitotic catastrophe evidencing micro- and multinucleation was also observed in cells exposed to our combination. CONCLUSIONS The combination of Cl-IB-MECA and paclitaxel causes significant cytotoxicity on two melanoma cell lines through multiple mechanisms of cell death. This multifactorial hit makes this therapy very promising as it will help to avoid melanoma multiresistance to chemotherapy and therefore potentially improve its treatment.
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12
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Vigneswara V, Akpan N, Berry M, Logan A, Troy CM, Ahmed Z. Combined suppression of CASP2 and CASP6 protects retinal ganglion cells from apoptosis and promotes axon regeneration through CNTF-mediated JAK/STAT signalling. ACTA ACUST UNITED AC 2014; 137:1656-75. [PMID: 24727569 DOI: 10.1093/brain/awu037] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We have previously shown that crushing the optic nerve induces death of retinal ganglion cells by apoptosis, but suppression of CASP2, which is predominantly activated in retinal ganglion cells, using a stably modified short interfering RNA CASP2, inhibits retinal ganglion cell apoptosis. Here, we report that combined delivery of short interfering CASP2 and inhibition of CASP6 using a dominant negative CASP6 mutant activates astrocytes and Müller cells, increases CNTF levels in the retina and leads to enhanced retinal ganglion cell axon regeneration. In dissociated adult rat mixed retinal cultures, dominant negative CASP6 mutant + short interfering CASP2 treatment also significantly increases GFAP+ glial activation, increases the expression of CNTF in culture, and subsequently increases the number of retinal ganglion cells with neurites and the mean retinal ganglion cell neurite length. These effects are abrogated by the addition of MAB228 (a monoclonal antibody targeted to the gp130 component of the CNTF receptor) and AG490 (an inhibitor of the JAK/STAT pathway downstream of CNTF signalling). Similarly, in the optic nerve crush injury model, MAB228 and AG490 neutralizes dominant negative CASP6 mutant + short interfering CASP2-mediated retinal ganglion cell axon regeneration, Müller cell activation and CNTF production in the retina without affecting retinal ganglion cell survival. We therefore conclude that axon regeneration promoted by suppression of CASP2 and CASP6 is CNTF-dependent and mediated through the JAK/STAT signalling pathway. This study offers insights for the development of effective therapeutics for promoting retinal ganglion cell survival and axon regeneration.
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Affiliation(s)
- Vasanthy Vigneswara
- 1 Neurotrauma and Neurodegeneration Section, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Nsikan Akpan
- 2 Department of Pathology and Cell Biology, Neurology, Taub Institute for Research on Alzheimer's Disease and the Ageing Brain, Columbia University Medical Centre, New York, USA
| | - Martin Berry
- 1 Neurotrauma and Neurodegeneration Section, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Ann Logan
- 1 Neurotrauma and Neurodegeneration Section, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Carol M Troy
- 2 Department of Pathology and Cell Biology, Neurology, Taub Institute for Research on Alzheimer's Disease and the Ageing Brain, Columbia University Medical Centre, New York, USA
| | - Zubair Ahmed
- 1 Neurotrauma and Neurodegeneration Section, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
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Abstract
Members of the caspase family of proteases are evolutionarily conserved cysteine proteases that play a crucial role as the central executioners of the apoptotic pathway. Since the discovery of caspases, many methods have been developed to detect their activation and are widely used in basic and clinical studies. In a mouse tissue, caspase activation can be monitored by cleavage of caspase-specific synthetic substrates and by detecting cleaved caspase by western blot analysis of the tissue extract. In tissue sections, active caspase can be detected by immunostaining using specific antibodies to the active caspase. In addition, among the myriads of caspase-specific substrates known so far, cleaved fragments produced by caspases from the substrates such as PARP, lamin A, and cytokeratin-18 can be monitored in tissue sections by immunostaining as well as western blots of tissue extracts. In general, more than one method should be used to ascertain detection of activation of caspases in a mouse tissue.
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14
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LeBlanc AC. Caspase-6 as a novel early target in the treatment of Alzheimer's disease. Eur J Neurosci 2013; 37:2005-18. [DOI: 10.1111/ejn.12250] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 04/01/2013] [Accepted: 04/06/2013] [Indexed: 12/16/2022]
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15
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Heise CE, Murray J, Augustyn KE, Bravo B, Chugha P, Cohen F, Giannetti AM, Gibbons P, Hannoush RN, Hearn BR, Jaishankar P, Ly CQ, Shah K, Stanger K, Steffek M, Tang Y, Zhao X, Lewcock JW, Renslo AR, Flygare J, Arkin MR. Mechanistic and structural understanding of uncompetitive inhibitors of caspase-6. PLoS One 2012; 7:e50864. [PMID: 23227217 PMCID: PMC3515450 DOI: 10.1371/journal.pone.0050864] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 10/25/2012] [Indexed: 01/13/2023] Open
Abstract
Inhibition of caspase-6 is a potential therapeutic strategy for some neurodegenerative diseases, but it has been difficult to develop selective inhibitors against caspases. We report the discovery and characterization of a potent inhibitor of caspase-6 that acts by an uncompetitive binding mode that is an unprecedented mechanism of inhibition against this target class. Biochemical assays demonstrate that, while exquisitely selective for caspase-6 over caspase-3 and -7, the compound's inhibitory activity is also dependent on the amino acid sequence and P1' character of the peptide substrate. The crystal structure of the ternary complex of caspase-6, substrate-mimetic and an 11 nM inhibitor reveals the molecular basis of inhibition. The general strategy to develop uncompetitive inhibitors together with the unique mechanism described herein provides a rationale for engineering caspase selectivity.
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Affiliation(s)
- Christopher E. Heise
- Department of Biochemical and Cellular Pharmacology, Genentech, Inc., South San Francisco, California, United States of America
| | - Jeremy Murray
- Department of Structural Biology, Genentech, Inc., South San Francisco, California, United States of America
| | - Katherine E. Augustyn
- Small Molecule Discovery Center, University of California San Francisco, San Francisco, California, United States of America
| | - Brandon Bravo
- Department of Biochemical and Cellular Pharmacology, Genentech, Inc., South San Francisco, California, United States of America
| | - Preeti Chugha
- Small Molecule Discovery Center, University of California San Francisco, San Francisco, California, United States of America
| | - Frederick Cohen
- Department of Discovery Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Anthony M. Giannetti
- Department of Biochemical and Cellular Pharmacology, Genentech, Inc., South San Francisco, California, United States of America
| | - Paul Gibbons
- Department of Discovery Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Rami N. Hannoush
- Department of Early Discovery Biochemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Brian R. Hearn
- Small Molecule Discovery Center, University of California San Francisco, San Francisco, California, United States of America
| | - Priyadarshini Jaishankar
- Small Molecule Discovery Center, University of California San Francisco, San Francisco, California, United States of America
| | - Cuong Q. Ly
- Department of Discovery Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Kinjalkumar Shah
- Department of Biochemical and Cellular Pharmacology, Genentech, Inc., South San Francisco, California, United States of America
| | - Karen Stanger
- Department of Early Discovery Biochemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Micah Steffek
- Department of Structural Biology, Genentech, Inc., South San Francisco, California, United States of America
| | - Yinyan Tang
- Small Molecule Discovery Center, University of California San Francisco, San Francisco, California, United States of America
| | - Xianrui Zhao
- Department of Discovery Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Joseph W. Lewcock
- Department of Neuroscience, Genentech, Inc., South San Francisco, California, United States of America
| | - Adam R. Renslo
- Small Molecule Discovery Center, University of California San Francisco, San Francisco, California, United States of America
| | - John Flygare
- Department of Discovery Chemistry, Genentech, Inc., South San Francisco, California, United States of America
| | - Michelle R. Arkin
- Small Molecule Discovery Center, University of California San Francisco, San Francisco, California, United States of America
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16
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Allosteric peptides bind a caspase zymogen and mediate caspase tetramerization. Nat Chem Biol 2012; 8:655-60. [PMID: 22683611 DOI: 10.1038/nchembio.967] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 04/10/2012] [Indexed: 11/08/2022]
Abstract
The caspases are a family of cytosolic proteases with essential roles in inflammation and apoptosis. Drug discovery efforts have focused on developing molecules directed against the active sites of caspases, but this approach has proved challenging and has not yielded any approved therapeutics. Here we describe a new strategy for generating inhibitors of caspase-6, a potential therapeutic target in neurodegenerative disorders, by screening against its zymogen form. Using phage display to discover molecules that bind the zymogen, we report the identification of a peptide that specifically impairs the function of caspase-6 in vitro and in neuronal cells. Remarkably, the peptide binds at a tetramerization interface that is uniquely present in zymogen caspase-6, rather than binding into the active site, and acts via a new allosteric mechanism that promotes caspase tetramerization. Our data illustrate that screening against the zymogen holds promise as an approach for targeting caspases in drug discovery.
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