TY - JOUR
T1 - LIM domain-binding 1 maintains the terminally differentiated state of pancreatic β cells
AU - Ediger, Benjamin N
AU - Lim, Hee-Woong
AU - Juliana, Christine
AU - Groff, David N
AU - Williams, LaQueena T
AU - Dominguez, Giselle
AU - Liu, Jin-Hua
AU - Taylor, Brandon L
AU - Walp, Erik R
AU - Kameswaran, Vasumathi
AU - Yang, Juxiang
AU - Liu, Chengyang
AU - Hunter, Chad S
AU - Kaestner, Klaus H
AU - Naji, Ali
AU - Li, Changhong
AU - Sander, Maike
AU - Stein, Roland
AU - Sussel, Lori
AU - Won, Kyoung-Jae
AU - May, Catherine Lee
AU - Stoffers, Doris A
PY - 2017/1/3
Y1 - 2017/1/3
N2 - The recognition of β cell dedifferentiation in type 2 diabetes raises the translational relevance of mechanisms that direct and maintain β cell identity. LIM domain-binding protein 1 (LDB1) nucleates multimeric transcriptional complexes and establishes promoter-enhancer looping, thereby directing fate assignment and maturation of progenitor populations. Many terminally differentiated endocrine cell types, however, remain enriched for LDB1, but its role is unknown. Here, we have demonstrated a requirement for LDB1 in maintaining the terminally differentiated status of pancreatic β cells. Inducible ablation of LDB1 in mature β cells impaired insulin secretion and glucose homeostasis. Transcriptomic analysis of LDB1-depleted β cells revealed the collapse of the terminally differentiated gene program, indicated by a loss of β cell identity genes and induction of the endocrine progenitor factor neurogenin 3 (NEUROG3). Lineage tracing confirmed that LDB1-depleted, insulin-negative β cells express NEUROG3 but do not adopt alternate endocrine cell fates. In primary mouse islets, LDB1 and its LIM homeodomain-binding partner islet 1 (ISL1) were coenriched at chromatin sites occupied by pancreatic and duodenal homeobox 1 (PDX1), NK6 homeobox 1 (NKX6.1), forkhead box A2 (FOXA2), and NK2 homeobox 2 (NKX2.2) - factors that co-occupy active enhancers in 3D chromatin domains in human islets. Indeed, LDB1 was enriched at active enhancers in human islets. Thus, LDB1 maintains the terminally differentiated state of β cells and is a component of active enhancers in both murine and human islets.
AB - The recognition of β cell dedifferentiation in type 2 diabetes raises the translational relevance of mechanisms that direct and maintain β cell identity. LIM domain-binding protein 1 (LDB1) nucleates multimeric transcriptional complexes and establishes promoter-enhancer looping, thereby directing fate assignment and maturation of progenitor populations. Many terminally differentiated endocrine cell types, however, remain enriched for LDB1, but its role is unknown. Here, we have demonstrated a requirement for LDB1 in maintaining the terminally differentiated status of pancreatic β cells. Inducible ablation of LDB1 in mature β cells impaired insulin secretion and glucose homeostasis. Transcriptomic analysis of LDB1-depleted β cells revealed the collapse of the terminally differentiated gene program, indicated by a loss of β cell identity genes and induction of the endocrine progenitor factor neurogenin 3 (NEUROG3). Lineage tracing confirmed that LDB1-depleted, insulin-negative β cells express NEUROG3 but do not adopt alternate endocrine cell fates. In primary mouse islets, LDB1 and its LIM homeodomain-binding partner islet 1 (ISL1) were coenriched at chromatin sites occupied by pancreatic and duodenal homeobox 1 (PDX1), NK6 homeobox 1 (NKX6.1), forkhead box A2 (FOXA2), and NK2 homeobox 2 (NKX2.2) - factors that co-occupy active enhancers in 3D chromatin domains in human islets. Indeed, LDB1 was enriched at active enhancers in human islets. Thus, LDB1 maintains the terminally differentiated state of β cells and is a component of active enhancers in both murine and human islets.
KW - Animals
KW - Basic Helix-Loop-Helix Transcription Factors/genetics
KW - Cell Differentiation
KW - DNA-Binding Proteins/genetics
KW - Diabetes Mellitus, Type 2/genetics
KW - Hepatocyte Nuclear Factor 3-beta/genetics
KW - Homeodomain Proteins/genetics
KW - Humans
KW - Insulin-Secreting Cells/metabolism
KW - LIM Domain Proteins/genetics
KW - LIM-Homeodomain Proteins/genetics
KW - Mice
KW - Mice, Transgenic
KW - Nerve Tissue Proteins/genetics
KW - Trans-Activators/genetics
KW - Transcription Factors/genetics
U2 - 10.1172/jci88016
DO - 10.1172/jci88016
M3 - Journal article
C2 - 27941246
SN - 0021-9738
VL - 127
SP - 215
EP - 229
JO - The Journal of Clinical Investigation
JF - The Journal of Clinical Investigation
IS - 1
ER -