Disrupting the DREAM complex enables proliferation of adult human pancreatic β cells
Peng Wang, … , James A. DeCaprio, Andrew F. Stewart
Peng Wang, … , James A. DeCaprio, Andrew F. Stewart
Published June 14, 2022
Citation Information: J Clin Invest. 2022;132(15):e157086. https://doi.org/10.1172/JCI157086.
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Research Article Endocrinology

Disrupting the DREAM complex enables proliferation of adult human pancreatic β cells

Abstract

Resistance to regeneration of insulin-producing pancreatic β cells is a fundamental challenge for type 1 and type 2 diabetes. Recently, small molecule inhibitors of the kinase DYRK1A have proven effective in inducing adult human β cells to proliferate, but their detailed mechanism of action is incompletely understood. We interrogated our human insulinoma and β cell transcriptomic databases seeking to understand why β cells in insulinomas proliferate, while normal β cells do not. This search reveals the DREAM complex as a central regulator of quiescence in human β cells. The DREAM complex consists of a module of transcriptionally repressive proteins that assemble in response to DYRK1A kinase activity, thereby inducing and maintaining cellular quiescence. In the absence of DYRK1A, DREAM subunits reassemble into the pro-proliferative MMB complex. Here, we demonstrate that small molecule DYRK1A inhibitors induce human β cells to replicate by converting the repressive DREAM complex to its pro-proliferative MMB conformation.

Authors

Peng Wang, Esra Karakose, Carmen Argmann, Huan Wang, Metodi Balev, Rachel I. Brody, Hembly G. Rivas, Xinyue Liu, Olivia Wood, Hongtao Liu, Lauryn Choleva, Dan Hasson, Emily Bernstein, Joao A. Paulo, Donald K. Scott, Luca Lambertini, James A. DeCaprio, Andrew F. Stewart

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Figure 1

NFAT expression and overexpression in human β cells.

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NFAT expression and overexpression in human β cells. (A) The current pre...
(A) The current prevailing mechanism of action model for the proliferative effects of DYRK1A inhibition. Cam, calmodulin; VDCC, voltage-dependent calcium channel. VIVIT is a small peptide NFAT-calcineurin inhibitor, FK506 is a calcineurin inhibitor. Harmine and INDY are small molecule inhibitors of DYRK1A. See main text for complete details. (B) Expression levels of the 4 human NFATs in RNA-seq from 22 sets of FACS-isolated human β cells, from Wang et al. (46). See Results for explanation of NFAT nomenclature. Values are in counts per million reads (CPM). (C) Expression of endogenous NFATs in human β cells assessed by immunohistochemistry. All are expressed, but only at low levels. (D) Overexpression by CMV promoter–driven adenovirus of wild-type human NFAT2 and -4. Note that these NFATs are predominantly cytoplasmic in human β cells. (E) Overexpression of constitutively active mouse NFAT1 and -2 in human islets, as detected with antibodies against NFAT1 and NFAT2. (F) Overexpression of constitutively active human NFAT2, -3, and -4. Note that in contrast to panels C and D, these are predominantly nuclear, as anticipated. Panels C–E are representative of 3 different human islet preparations. Here again, NFAT expression is predominantly nuclear in β cells, as anticipated. (G and H) Effect of overexpression of wild-type and constitutively active NFATs on Ki67 immunolabeling in human β cells in islets from 5 (G) or 6 (H) different organ donors, compared to the DYRK1A inhibitor harmine, a positive control, and to the negative control, an adenovirus expressing Cre recombinase, all at the same MOI as the NFATs. Data are presented as mean ± SEM. 2-tailed Student’s paired t test, *P < 0.05; **P < 0.01. (I) Examples of Ki67 immunolabeling in human islets under the conditions shown. Scale bars: 10 μm.