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The transrepression arm of glucocorticoid receptor signaling is protective in mutant huntingtin-mediated neurodegeneration

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journal contribution
posted on 04.03.2015, 15:31 by S. Varadarajan, Carlo Breda, Joshua L. Smalley, Michael Butterworth, S. N. Farrow, Flaviano Giorgini, G. M. Cohen
The unfolded protein response (UPR) occurs following the accumulation of unfolded proteins in the endoplasmic reticulum (ER) and orchestrates an intricate balance between its pro-survival and apoptotic arms to restore cellular homeostasis and integrity. However, in certain neurodegenerative diseases, the apoptotic arm of the UPR is enhanced, resulting in excessive neuronal cell death and disease progression, both of which can be overcome by modulating the UPR. Here, we describe a novel crosstalk between glucocorticoid receptor signaling and the apoptotic arm of the UPR, thus highlighting the potential of glucocorticoid therapy in treating neurodegenerative diseases. Several glucocorticoids, but not mineralocorticoids, selectively antagonize ER stress-induced apoptosis in a manner that is downstream of and/or independent of the conventional UPR pathways. Using GRT10, a novel selective pharmacological modulator of glucocorticoid signaling, we describe the importance of the transrepression arm of the glucocorticoid signaling pathway in protection against ER stress-induced apoptosis. Furthermore, we also observe the protective effects of glucocorticoids in vivo in a Drosophila model of Huntington’s disease (HD), wherein treatment with different glucocorticoids diminished rhabdomere loss and conferred neuroprotection. Finally, we find that growth differentiation factor 15 (GDF15) plays an important role downstream of glucocorticoid signaling in antagonising ER stress-induced apoptosis in cells, as well as in preventing HD-mediated neurodegeneration in flies. Thus, our studies demonstrate that this novel crosstalk has the potential to be effectively exploited in alleviating several neurodegenerative disorders.

Funding

We thank the Medical Research Council Toxicology Unit for core support, and the CHDI Foundation Inc. for funding (to FG)

History

Citation

Cell Death and Differentiation (2015), 1–9

Author affiliation

/Organisation/COLLEGE OF MEDICINE, BIOLOGICAL SCIENCES AND PSYCHOLOGY/School of Biological Sciences/Department of Genetics

Version

AM (Accepted Manuscript)

Published in

Cell Death and Differentiation (2015)

Publisher

Nature Publishing Group

issn

1350-9047

eissn

1476-5403

Copyright date

2015

Available date

06/08/2015

Publisher version

http://www.nature.com/cdd/journal/vaop/ncurrent/full/cdd20151a.html

Language

en