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Abstract
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The biological responses to dienone compounds with a 1,5-diaryl-3-oxo-1,4-pentadienyl
pharmacophore have been studied extensively. Despite their expected
general thiol reactivity, these compounds display considerable degrees
of tumor cell selectivity. Here we review in vitro and preclinical studies of dienone compounds including b-AP15, VLX1570,
RA-9, RA-190, EF24, HO-3867, and MCB-613. A common property of these
compounds is their targeting of the ubiquitin–proteasome system
(UPS), known to be essential for the viability of tumor cells. Gene
expression profiling experiments have shown induction of responses
characteristic of UPS inhibition, and experiments using cellular reporter
proteins have shown that proteasome inhibition is associated with
cell death. Other mechanisms of action such as reactivation of mutant
p53, stimulation of steroid receptor coactivators, and induction of
protein cross-linking have also been described. Although unsuitable
as biological probes due to widespread reactivity, dienone compounds
are cytotoxic to apoptosis-resistant tumor cells and show activity
in animal tumor models.
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Affiliation(s)
- Martina Bazzaro
- Masonic Cancer Center and Department of Obstetrics, Gynecology and Women's Heath, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Stig Linder
- Department of Biomedical and Clinical Sciences (BKV), Linköping University, SE-58183 Linköping, Sweden.,Department of Oncology and Pathology, Karolinska Institute, SE-17176 Stockholm, Sweden
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Coombes CE, Saunders HAJ, Mannava AG, Johnson-Schlitz DM, Reid TA, Parmar S, McClellan M, Yan C, Rogers SL, Parrish JZ, Wagenbach M, Wordeman L, Wildonger J, Gardner MK. Non-enzymatic Activity of the α-Tubulin Acetyltransferase αTAT Limits Synaptic Bouton Growth in Neurons. Curr Biol 2020; 30:610-623.e5. [PMID: 31928876 DOI: 10.1016/j.cub.2019.12.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 10/16/2019] [Accepted: 12/06/2019] [Indexed: 10/25/2022]
Abstract
Neuronal axons terminate as synaptic boutons that form stable yet plastic connections with their targets. Synaptic bouton development relies on an underlying network of both long-lived and dynamic microtubules that provide structural stability for the boutons while also allowing for their growth and remodeling. However, a molecular-scale mechanism that explains how neurons appropriately balance these two microtubule populations remains a mystery. We hypothesized that α-tubulin acetyltransferase (αTAT), which both stabilizes long-lived microtubules against mechanical stress via acetylation and has been implicated in promoting microtubule dynamics, could play a role in this process. Using the Drosophila neuromuscular junction as a model, we found that non-enzymatic dαTAT activity limits the growth of synaptic boutons by affecting dynamic, but not stable, microtubules. Loss of dαTAT results in the formation of ectopic boutons. These ectopic boutons can be similarly suppressed by resupplying enzyme-inactive dαTAT or by treatment with a low concentration of the microtubule-targeting agent vinblastine, which acts to suppress microtubule dynamics. Biophysical reconstitution experiments revealed that non-enzymatic αTAT1 activity destabilizes dynamic microtubules but does not substantially impact the stability of long-lived microtubules. Further, during microtubule growth, non-enzymatic αTAT1 activity results in increasingly extended tip structures, consistent with an increased rate of acceleration of catastrophe frequency with microtubule age, perhaps via tip structure remodeling. Through these mechanisms, αTAT enriches for stable microtubules at the expense of dynamic ones. We propose that the specific suppression of dynamic microtubules by non-enzymatic αTAT activity regulates the remodeling of microtubule networks during synaptic bouton development.
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Affiliation(s)
- Courtney E Coombes
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Harriet A J Saunders
- Integrated Program in Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Anirudh G Mannava
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | | | - Taylor A Reid
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Sneha Parmar
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Mark McClellan
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Connie Yan
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Stephen L Rogers
- Department of Biology, Integrative Program for Biological and Genome Sciences, and Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jay Z Parrish
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Michael Wagenbach
- Department of Physiology and Biophysics, The University of Washington, Seattle, WA 98195, USA
| | - Linda Wordeman
- Department of Physiology and Biophysics, The University of Washington, Seattle, WA 98195, USA
| | - Jill Wildonger
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Melissa K Gardner
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA.
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Lu L, Arizmendi N, Kulka M, Unsworth LD. The Spontaneous Adhesion of BMMC onto Self-Assembled Peptide Nanoscaffold without Activation Inhibits Its IgE-Mediated Degranulation. Adv Healthc Mater 2017; 6. [PMID: 28665558 DOI: 10.1002/adhm.201700334] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/18/2017] [Indexed: 11/11/2022]
Abstract
Mast cells play a distinct role in the innate immune response. Engineered microenvironments for the express purpose of influencing mast cell activity will provide a novel means of designing biomaterials, as well as a means to systematically investigate mast cell biology in a 3D setting. Here, the effect of nanoscaffolds composed of self-assembling peptides, namely (RADA)4 , on bone-marrow-derived murine mast cell (BMMC) activity is reported. Unlike most studies that stimulate mast cells to induce adhesion, this results show that BMMCs spontaneously adhere to the artificial nanoscaffold without initiating their activation. It is observed that the classical immunoglobulin (IgE) antigen-mediated degranulation of adhered BMMC is inhibited by the nanoscaffold, while non-IgE (A23187)-induced degranulation is unaffected. The inhibition of IgE-antigen-mediated degranulation is likely a result of inhibited molecular diffusion within the matrix; antigen diffusion, IgE-FcεRI complex shuttling, and/or formation of multiple IgE-FcεRI clusters may be physically hindered in the presence of the polyvalent nanofiber network. Moreover, the IgE/antigen-induced inflammatory cytokine tumor necrosis factor α release from adherent BMMCs is significantly reduced likely due to interaction with the nanofiber matrix. This work is considered the first step in quantifying mast cell activity in artificial matrices composed of self-assembling peptides.
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Affiliation(s)
- Lei Lu
- DICE 13‐390 Department of Chemical and Materials Engineering University of Alberta 9211‐116 Street NW Edmonton AB T6G 1H9 Canada
- National Institute for Nanotechnology 11421 Saskatchewan Dr NW Edmonton AB T6G 2M93 Canada
| | - Narcy Arizmendi
- National Institute for Nanotechnology 11421 Saskatchewan Dr NW Edmonton AB T6G 2M93 Canada
| | - Marianna Kulka
- National Institute for Nanotechnology 11421 Saskatchewan Dr NW Edmonton AB T6G 2M93 Canada
- Department of Medical Microbiology and Immunology University of Alberta Edmonton AB T6G 2E1 Canada
| | - Larry D. Unsworth
- DICE 13‐390 Department of Chemical and Materials Engineering University of Alberta 9211‐116 Street NW Edmonton AB T6G 1H9 Canada
- National Institute for Nanotechnology 11421 Saskatchewan Dr NW Edmonton AB T6G 2M93 Canada
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Perraut F, Doménès M, Grateau H, Josso Q. Achieving magnification smaller than 1 in lensless microscopy by illumination with a convergent wavefront. OPTICS LETTERS 2016; 41:5326-5328. [PMID: 27842124 DOI: 10.1364/ol.41.005326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Lensless or lensfree microscopy is now available commercially. With these new microscopes, it is possible to record images in contact mode with a magnification of 1 or in holographic mode with a magnification larger than 1. In this Letter, we present an original setup that allows us to record the image of an object whose surface is larger than that of the image sensor without placing an optical component between the object and the image sensor.
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