Douglas A. Melton's research while affiliated with Harvard University and other places

Publications (207)

Preprint
Immunological protection of transplanted stem cell-derived islet (SC-islet) cells is yet to be achieved without chronic immunosuppression or encapsulation. Existing genetic engineering approaches to produce hypoimmunogenic SC-islet cells have so far shown variable results. Here, we show that targeting the human leukocyte antigens (HLAs) and PD-L1 a...
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The in vitro production of stem-cell-derived islets (SC-islets) has brought forth the potential of transplanting these cells to restore glycemic control in people with diabetes. Nonetheless, alloimmune and autoimmune responses remain considerable challenges for a broad clinical implementation of β-cell replacement therapies. β-cell stress has been...
Article
How cells become specialized, or “mature,” is important for cell and developmental biology. While maturity is usually deemed a terminal fate, it may be more helpful to consider maturation not as a switch but as a dynamic continuum of adaptive phenotypic states set by genetic and environment programing. The hallmarks of maturity comprise changes in...
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Human pluripotent stem cells (hPSC) can be directed to differentiate in vitro into insulin-prorducing beta cells (SC-β). Although these cells accurately respond to glucose and can reverse diabetes in preclinical models improvments in the final cell products are desirable. For example, safety, controlling the cellular compositions and protection aga...
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Islet transplantation for type 1 diabetes treatment has been limited by the need for lifelong immunosuppression regimens. This challenge has prompted the development of macroencapsulation devices (MEDs) to immunoprotect the transplanted islets. While promising, conventional MEDs are faced with insufficient transport of oxygen, glucose, and insulin...
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Present-day treatments for people that are insulin dependent require multiple insulin injections, sometimes with an insulin pump, coupled with regular blood glucose monitoring. The availability of modified insulins, each with peaks of activity at varying times, has improved diabetes management. On the other hand, there have been impressive results...
Article
Diabetes is a disease of insulin insufficiency, requiring many to rely on exogenous insulin with constant monitoring to avoid a fatal outcome. Islet transplantation is a recent therapy that can provide insulin independence, but the procedure is still limited by both the availability of human islets and reliable tests to assess their function. While...
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Stem cell-derived tissues that recap endogenous physiology are key for regenerative medicine. Yet, most methods yield products that function like fetal, not adult tissues. Organoids are typically grown in constant environments, while our tissues mature along with behavioral cycles. Here, we show that inducing circadian rhythms in pancreatic islet o...
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Type 1 diabetes (T1D) is caused by the autoimmune destruction of pancreatic beta cells. Pluripotent stem cells can now be differentiated into beta cells, thus raising the prospect of a cell replacement therapy for T1D. However, autoimmunity would rapidly destroy newly transplanted beta cells. Using a genome-scale CRISPR screen in a mouse model for...
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Understanding the root causes of autoimmune diseases is hampered by the inability to access relevant human tissues and identify the time of disease onset. To examine the interaction of immune cells and their cellular targets in type 1 diabetes, we differentiated human induced pluripotent stem cells into pancreatic endocrine cells, including β cells...
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Stem‐cell‐derived tissues offer platforms to study organ development, model physiology during health and disease, and test novel therapies. We describe methods to isolate cells at successive stages during in vitro differentiation of human stem cells into the pancreatic endocrine lineage. Using flow cytometry, we purify live lineage intermediates in...
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Stem cell-derived β (SC-β) cells could provide unlimited human β cells toward a curative diabetes treatment. Differentiation of SC-β cells yields transplantable islets that secrete insulin in response to glucose challenges. Following transplantation into mice, SC-β cell function is comparable to human islets, but the magnitude and consistency of re...
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The generation of pancreatic cell types from renewable cell sources holds promise for cell replacement therapies for diabetes. Although most effort has focused on generating pancreatic beta cells, considerable evidence indicates that glucagon secreting alpha cells are critically involved in disease progression and proper glucose control. Here we re...
Article
A drastic transition at birth, from constant maternal nutrient supply in utero to intermittent postnatal feeding, requires changes in the metabolic system of the neonate. Despite their central role in metabolic homeostasis, little is known about how pancreatic β cells adjust to the new nutritional challenge. Here, we find that after birth β cell fu...
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Insulin resistance is associated with aging in mice and humans. We have previously shown that administration of recombinant GDF11 (rGDF11) to aged mice alters aging phenotypes in the brain, skeletal muscle, and heart. While the closely related protein GDF8 has a role in metabolism, limited data are available on the potential metabolic effects of GD...
Article
Treatment of type 1 diabetes with insulin injection is expensive, complicated, and insufficient. While cadaveric islet transplantations coupled with immunosuppressants can cure diabetes, the scarcity of acceptable islets is problematic. Developmental research on pancreas formation has informed in vitro differentiation of human pluripotent stem cell...
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Formation of a specialized wound epidermis is required to initiate salamander limb regeneration. Yet little is known about the roles of the early wound epidermis during the initiation of regeneration and the mechanisms governing its development into the apical epithelial cap (AEC), a signaling structure necessary for outgrowth and patterning of the...
Article
The beta (β)-cell mass formed during embryogenesis is amplified by cell replication during fetal and early postnatal development. Thereafter, β cells become functionally mature, and their mass is maintained by a low rate of replication. For those few β cells that replicate in adult life, it is not known how replication is initiated nor whether this...
Article
Stem-cell-derived tissues could transform disease research and therapy, yet most methods generate functionally immature products. We investigate how human pluripotent stem cells (hPSCs) differentiate into pancreatic islets in vitro by profiling DNA methylation, chromatin accessibility, and histone modification changes. We find that enhancer potenti...
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Our laboratory and others have developed protocols to generate glucose‐responsive stem cell–derived β cells in vitro. The cells resulting from these protocols could supplement or replace the use of human cadaveric islets for cell‐based therapy for diabetes. The combination of an unlimited supply of pluripotent stem cell–derived β cells and gene‐edi...
Article
Background: Current differentiation protocols to produce cardiomyocytes from human induced pluripotent stem cells (iPSCs) are capable of generating highly pure cardiomyocyte populations as determined by expression of cardiac troponin T. However, these cardiomyocytes remain immature, more closely resembling the fetal state, with a lower maximum con...
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Pancreatic β cell function is compromised in diabetes and is typically assessed by measuring insulin secretion during glucose stimulation. Traditionally, measurement of glucose-stimulated insulin secretion involves manual liquid handling, heterogeneous stimulus delivery, and enzyme-linked immunosorbent assays that require large numbers of islets an...
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Identifying gene expression programs underlying both cell-type identity and cellular activities (e.g. life-cycle processes, responses to environmental cues) is crucial for understanding the organization of cells and tissues. Although single-cell RNA-Seq (scRNA-Seq) can quantify transcripts in individual cells, each cell's expression profile may be...
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In vitro differentiation of pluripotent cells into β cells is a promising alternative to cadaveric-islet transplantation as a cure for type 1 diabetes (T1D). During the directed differentiation of human embryonic stem cells (hESCS) by exogenous factors, numerous genes that affect the differentiation process are turned on and off autonomously. Manip...
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In vitro differentiation of human stem cells can produce pancreatic β-cells; the loss of this insulin-secreting cell type underlies type 1 diabetes. Here, as a step towards understanding this differentiation process, we report the transcriptional profiling of more than 100,000 human cells undergoing in vitro β-cell differentiation, and describe the...
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Polymorphic HLAs form the primary immune barrier to cell therapy. In addition, innate immune surveillance impacts cell engraftment, yet a strategy to control both, adaptive and innate immunity, is lacking. Here we employed multiplex genome editing to specifically ablate the expression of the highly polymorphic HLA-A/-B/-C and HLA class II in human...
Preprint
Full-text available
Investigating pancreatic islet differentiation from human stem cells in vitro provides a unique opportunity to dissect mechanisms that operate during human development in utero. We developed methods to profile DNA methylation, chromatin accessibility, and histone modifications from pluripotent stem cells to mature pancreatic islet cells, uncovering...
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Stem cell-derived insulin-producing beta cells (SC-β) offer an inexhaustible supply of functional β cells for cell replacement therapies and disease modeling for diabetes. While successful directed differentiation protocols for this cell type have been described, the mechanisms controlling its differentiation and function are not fully understood....
Article
The retraction of >30 falsified studies by Anversa et al. has had a disheartening impact on the cardiac cell therapeutics field. The premise of heart muscle regeneration by the transdifferentiation of bone marrow cells or putative adult resident cardiac progenitors has been largely disproven. Over the past 18 years, a generation of physicians and s...
Article
Pancreatic β‐cell replacement by islet transplantation for the treatment of Type 1 Diabetes (T1D) is currently limited by donor tissue scarcity and the requirement for lifelong immunosuppression. The advent of in vitro differentiation protocols for generating functional β‐like cells from human pluripotent stem cells, so‐called SC‐β cells, could eli...
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Blastema formation, a hallmark of limb regeneration, requires proliferation and migration of progenitors to the amputation plane. Although blastema formation has been well described, the transcriptional programs that drive blastemal progenitors remain unknown. We transcriptionally profiled dividing and non-dividing cells in regenerating stump tissu...
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The in vivo microenvironment of tissues provides myriad unique signals to cells. Thus, following isolation, many cell types change in culture, often preserving some but not all of their in vivo characteristics in culture. At least some of the in vivo microenvironment may be mimicked by providing specific cues to cultured cells. Here, we show that a...
Data
Supporting information data. This file contains the list of primers used in this study and supplementary materials and methods. (PDF)
Data
JAK/STAT inhibition does not affect islet viability. Whole pancreatic rat islets were cultured for a period of 14 days with or without ApoE together with JAK/STAT inhibitors. Comparable levels of viable and dead cells were detected between the two groups. Scale bar, 50 uM. Data presented as mean ± SEM, where n.s. means not significant (n = 10). (EP...
Data
Whole islet gene expression profile is lost in adherent cultures in vitro. Gene expression analysis of β-cell transcription factors from rat pancreatic whole islets cultured under low glucose (5 mM) conditions for 2 weeks shows reduced gene expression over time (n = 4). (EPS)
Data
Effect of ApoE on islets cultured in suspension and on human islets. A) Whole human pancreatic islets were cultured for a period of 7 days under physiological glucose (11 mM) conditions with or without ApoE. Comparable levels of key β-cell markers was observed. B) Human islets were cultured for 7 days in 804G coated plates with and without ApoE. Ea...
Data
ApoE enhances islet gene expression profile in vitro. A) Whole rat pancreatic islets were cultured for a period of 14 days with or without ApoE under low glucose (5 mM) conditions. ApoE significantly increased the expression of key β-cell markers including Ins2, Ucn3, Glut2, Nkx2.2, Nkx6.1, Pcsk1, Sur1 and Pc. B) Whole rat pancreatic Islets were cu...
Data
ApoE Treatment does not stimulate islet cell proliferation. Whole rat pancreatic islets were cultured for a period of 14 days with or without ApoE together with BrdU. Very low levels of BrdU positive cells were detected in both groups. Scale bar, 50 uM. Data presented as mean ± SEM, where n.s. means not significant (n = 10). (EPS)
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Change history: In this Insight Review, '1989' has been changed to '1998' in the sentence "This deep understanding of pancreatic development was put to the service of regenerative medicine in 1998, when human embryonic stem cells (hES cells) were successfully cultured and opened the door to developing methods of deriving pancreatic islets from hES...
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The pancreas is made from two distinct components: the exocrine pancreas, a reservoir of digestive enzymes, and the endocrine islets, the source of the vital metabolic hormone insulin. Human islets possess limited regenerative ability; loss of islet β-cells in diseases such as type 1 diabetes requires therapeutic intervention. The leading strategy...
Preprint
Full-text available
Identifying gene expression programs underlying cell-type identity and cellular processes is a crucial step toward understanding the organization of cells and tissues. Although single-cell RNA-Seq (scRNA-Seq) can quantify transcripts in individual cells, each cell's expression may derive both from programs determining cell-type and from programs fa...
Article
Full-text available
Beta cell replacement has the potential to restore euglycemia in patients with insulin dependent diabetes. While great progress has been made in establishing allogeneic islet transplantation from deceased donors as the standard of care for those with the most labile diabetes, it is also clear that the deceased donor organ supply cannot possibly tre...
Article
Type 1 diabetes is characterized by autoimmune destruction of β cells located in pancreatic islets. However, tractable in vivo models of human pancreatic β cells have been limited. Here, we generated xenogeneic human pancreatic β-like cells in the mouse pancreas by orthotopic transplantation of stem cell-derived β (SC-β) cells into the pancreas of...
Article
(Cell 153, 747–758; May 9, 2013) In this article, we claimed that Angptl-8, which we termed betatrophin and is also referred to in the literature as TD26, RIFL, C19orf80, and Lipasin, was the agent by which the insulin antagonist S961 induces robust β cell replication in mice. Gusarova et al., in a Matters Arising article, subsequently showed that...
Article
Although the function of the mammalian pancreas hinges on complex interactions of distinct cell types, gene expression profiles have primarily been described with bulk mixtures. Here we implemented a droplet-based, single-cell RNA-seq method to determine the transcriptomes of over 12,000 individual pancreatic cells from four human donors and two mo...
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Nature Communications 7: Article number: 11463 (2016); Published: 10 May 2016; Updated: 4 August 2016. The source of reagents for this Article was not fully acknowledged. The Acknowledgements should have included the following: ‘We thank Professors Robin Goland and Dieter Egli (https://www.cellhub.org) for patient fibroblasts.
Data
Individual data for islet cell Ki67 proliferation based on stained slides described in Fig 3. Measurements were recorded from 10-week-old CD1 male mice injected with maltose binding protein (MBP; control) or MBP-human betatrophin (hBT) fusion protein for two days and sacrificed on day three. Islet cells were identified by dilating the insulin area...
Data
Individual physiologic data. Measurements were recorded from 10-week-old CD1 male mice injected with buffer (with or without EdU), maltose binding protein (MBP; control) or MBP-human betatrophin (hBT) fusion protein for two days and sacrificed on day three. Initial and final body weight (g), initial and final random fed blood glucose (mg/dl), rando...
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The β-cell mitogenic effects of ANGPTL8 have been subjected to substantial debate. The original findings suggested that ANGPTL8 overexpression in mice induced a 17-fold increase in β-cell proliferation. Subsequent studies in mice contested this claim, but a more recent report in rats supported the original observations. These conflicting results mi...
Data
Individual data for Ki67, EdU co-expressing total cell and β-cell analysis. Measurements were recorded from 10-week-old CD1 male mice injected with maltose binding protein (MBP; control) or MBP-human betatrophin (hBT) fusion protein for two days and sacrificed on day three. Quantification of Ki67+ EdU+ cells as a percenatge of total cells or β-cell...
Data
In a separate eperiment, acute administration of ANGPTL8 transiently increased serum triglycerides. Measurements were recorded from mice injected with maltose binding protein (MBP; control), MBP-human betatrophin (hBT) fusion protein, or various concentrations of lipase inhibitor (increases serum triglyceride) and followed for two days. Final body...
Data
Individual data for β-cell proliferation analysis from all three labs for ANGPTL8 treatment studies. (top panel) Total β-cells counted for Ki67, total Ki67+ insulin+ DAPI+ cells, and Ki67+ β-cells (% of total insulin+ cells) for the tail pancreas. (bottom panel) Total β-cells counted, total EdU+ insulin+ DAPI+ cells, and EdU+ β-cells (% of total in...
Data
Code for MBP and MBP+hBT injections. (XLSX)
Data
Individual data for exocrine cell proliferation for ANGPTL8 treatment studies. Measurements were recorded from 10-week-old CD1 male mice injected with maltose binding protein (MBP; control) or MBP-human betatrophin (hBT) fusion protein for two days and sacrificed on day three. Quantification of pancreatic proliferation by Ki67 or EdU (% of total ex...
Data
Individual data for islet cell, β-cell, and non-β islet cell counts & proliferation using Nkx6.1 as a marker for β-cells. Measurements were recorded from 10-week-old CD1 male mice injected with maltose binding protein (MBP; control) or MBP-human betatrophin (hBT) fusion protein for two days and sacrificed on day three. Islet cells were identified b...
Article
Full-text available
We recently reported the scalable in vitro production of functional stem cell-derived β-cells (SC-β cells). Here we extend this approach to generate the first SC-β cells from type 1 diabetic patients (T1D). β-cells are destroyed during T1D disease progression, making it difficult to extensively study them in the past. These T1D SC-β cells express β...
Article
The gastrointestinal (GI) epithelium is a highly regenerative tissue with the potential to provide a renewable source of insulin(+) cells after undergoing cellular reprogramming. Here, we show that cells of the antral stomach have a previously unappreciated propensity for conversion into functional insulin-secreting cells. Native antral endocrine c...
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The transplantation of glucose-responsive, insulin-producing cells offers the potential for restoring glycemic control in individuals with diabetes. Pancreas transplantation and the infusion of cadaveric islets are currently implemented clinically, but these approaches are limited by the adverse effects of immunosuppressive therapy over the lifetim...
Article
Understanding the genes and signaling pathways that determine the differentiation and fate of a cell is a central goal of developmental biology. Using that information to gain mastery over the fates of cells presents new approaches to cell transplantation and drug discovery for human diseases including diabetes.
Article
Type 2 diabetes is characterized by a reduction in insulin function and an increase in glucagon activity that together result in hyperglycemia. Glucagon receptor antagonists have been developed as drugs for diabetes; however, they often increase glucagon plasma levels and induce the proliferation of glucagon-secreting α-cells. We find that the secr...