Explore the vast range of titles available.

ContextVariation in genes that cause maturity-onset diabetes of the young (MODY) has been associated with diabetes incidence and glycemic traits.ObjectivesThis study aimed to determine whether genetic variation in MODY genes leads to differential responses to insulin-sensitizing interventions.Design and SettingThis was a secondary analysis of a multicenter, randomized clinical trial, the Diabetes Prevention Program (DPP), involving 27 US academic institutions. We genotyped 22 missense and 221 common variants in the MODY-causing genes in the participants in the DPP.Participants and InterventionsThe study included 2806 genotyped DPP participants randomized to receive intensive lifestyle intervention (n = 935), metformin (n = 927), or placebo (n = 944).Main Outcome MeasuresAssociation of MODY genetic variants with diabetes incidence at a median of 3 years and measures of 1-year β-cell function, insulinogenic index, and oral disposition index. Analyses were stratified by treatment group for significant single-nucleotide polymorphism × treatment interaction (Pint < 0.05). Sequence kernel association tests examined the association between an aggregate of rare missense variants and insulinogenic traits.ResultsAfter 1 year, the minor allele of rs3212185 (HNF4A) was associated with improved β-cell function in the metformin and lifestyle groups but not the placebo group; the minor allele of rs6719578 (NEUROD1) was associated with an increase in insulin secretion in the metformin group but not in the placebo and lifestyle groups.ConclusionsThese results provide evidence that genetic variation among MODY genes may influence response to insulin-sensitizing interventions.Genetic variation in MODY genes was associated with response to diabetes prevention interventions as measured by β-cell function and diabetes incidence.

Monogenic diabetes refers to diabetes mellitus (DM) caused by a mutation in a single gene and accounts for approximately 1%-5% of diabetes. Correct diagnosis is clinically critical for certain types of monogenic diabetes, since the appropriate treatment is determined by the etiology of the disease (e.g., oral sulfonylurea treatment of HNF1A/HNF4A-diabetes vs. insulin injections in type 1 diabetes). However, achieving a correct diagnosis requires genetic testing, and the overlapping of the clinical features of monogenic diabetes with those of type 1 and type 2 diabetes has frequently led to misdiagnosis. Improvements in sequencing technology are increasing opportunities to diagnose monogenic diabetes, but challenges remain. In this Review, we describe the types of monogenic diabetes, including common and uncommon types of maturity-onset diabetes of the young, multiple causes of neonatal DM, and syndromic diabetes such as Wolfram syndrome and lipodystrophy. We also review methods of prioritizing patients undergoing genetic testing, and highlight existing challenges facing sequence data interpretation that can be addressed by forming collaborations of expertise and by pooling cases.

B cells and follicular helper T cells in B cell follicles can act as important reservoirs for chronic infection by viruses such as HIV or EBV. Yu and colleagues show that a specialized subpopulation of cytotoxic T cells can enter the B cell follicles to eliminate such virus-infected cells. During unresolved infections, some viruses escape immunological control and establish a persistant reservoir in certain cell types, such as human immunodeficiency virus (HIV), which persists in follicular helper T cells (T FH cells), and Epstein-Barr virus (EBV), which persists in B cells. Here we identified a specialized group of cytotoxic T cells (T C cells) that expressed the chemokine receptor CXCR5, selectively entered B cell follicles and eradicated infected T FH cells and B cells. The differentiation of these cells, which we have called 'follicular cytotoxic T cells' (T FC cells), required the transcription factors Bcl6, E2A and TCF-1 but was inhibited by the transcriptional regulators Blimp1, Id2 and Id3. Blimp1 and E2A directly regulated Cxcr5 expression and, together with Bcl6 and TCF-1, formed a transcriptional circuit that guided T FC cell development. The identification of T FC cells has far-reaching implications for the development of strategies to control infections that target B cells and T FH cells and to treat B cell–derived malignancies.

Elevated serum urate levels cause gout and correlate with cardiometabolic diseases via poorly understood mechanisms. We performed a trans-ancestry genome-wide association study of serum urate in 457,690 individuals, identifying 183 loci (147 previously unknown) that improve the prediction of gout in an independent cohort of 334,880 individuals. Serum urate showed significant genetic correlations with many cardiometabolic traits, with genetic causality analyses supporting a substantial role for pleiotropy. Enrichment analysis, fine-mapping of urate-associated loci and colocalization with gene expression in 47 tissues implicated the kidney and liver as the main target organs and prioritized potentially causal genes and variants, including the transcriptional master regulators in the liver and kidney, HNF1A and HNF4A . Experimental validation showed that HNF4A transactivated the promoter of ABCG2 , encoding a major urate transporter, in kidney cells, and that HNF4A p.Thr139Ile is a functional variant. Transcriptional coregulation within and across organs may be a general mechanism underlying the observed pleiotropy between urate and cardiometabolic traits. A trans-ancestry genome-wide association study of serum urate levels identifies 183 loci influencing this trait. Enrichment analyses, fine-mapping and colocalization with gene expression in 47 tissues implicate the kidney and liver as key target organs and prioritize potential causal genes.

HNF4A and HNF1A encode transcription factors that are important for the development and function of the pancreas and liver. Mutations in both genes have been directly linked to Maturity Onset Diabetes of the Young (MODY) and type 2 diabetes (T2D) risk. To better define the pleiotropic gene regulatory roles of HNF4A and HNF1A, we generated a comprehensive genome-wide map of their binding targets in pancreatic and hepatic cells using ChIP-Seq. HNF4A was found to bind and regulate known ( ACY3 , HAAO, HNF1A , MAP3K11 ) and previously unidentified ( ABCD3 , CDKN2AIP , USH1C , VIL1 ) loci in a tissue-dependent manner. Functional follow-up highlighted a potential role for HAAO and USH1C as regulators of beta cell function. Unlike the loss-of-function HNF4A/MODY1 variant I271fs, the T2D-associated HNF4A variant (rs1800961) was found to activate AKAP1 , GAD2 and HOPX gene expression, potentially due to changes in DNA-binding affinity. We also found HNF1A to bind to and regulate GPR39 expression in beta cells. Overall, our studies provide a rich resource for uncovering downstream molecular targets of HNF4A and HNF1A that may contribute to beta cell or hepatic cell (dys)function, and set up a framework for gene discovery and functional validation. Here, the authors generated a genome-wide map of the global targets bound by HNF4A and HNF1A in beta cells and hepatic cells, and highlighted notable downstream pathways and target genes that may influence beta cell function. This approach also shed light on a potentially activating effect of a HNF4A type 2 diabetes risk variant.

Direct routes to liver-like cells Two groups report new approaches that could lead to the generation of hepatocyte-like cells for liver engineering and regenerative medicine. Lijian Hui and colleagues use a combination of Gata4, Hnf1a and Foxa3 overexpression and p19Arf inactivation to convert mouse fibroblasts directly into induced hepatic (iHep) cells that have gene-expression profiles close to that of mature hepatocytes. Sayaka Sekiya and Atsushi Suzuki identify three combinations of two transcription factors, comprising Hnf4a plus Foxa1, Foxa2 or Foxa3, that can convert mouse embryonic and adult fibroblasts directly into functional iHep cells. Both groups show that when iHep cells are transplanted into mice with a gene deficiency that models liver injury, the cells are able to repopulate the livers and restore their function. The generation of functional hepatocytes independent of donor liver organs is of great therapeutic interest with regard to regenerative medicine and possible cures for liver disease 1 . Induced hepatic differentiation has been achieved previously using embryonic stem cells or induced pluripotent stem cells 2 , 3 , 4 , 5 , 6 , 7 , 8 . Particularly, hepatocytes generated from a patient’s own induced pluripotent stem cells could theoretically avoid immunological rejection. However, the induction of hepatocytes from induced pluripotent stem cells is a complicated process that would probably be replaced with the arrival of improved technology. Overexpression of lineage-specific transcription factors directly converts terminally differentiated cells into some other lineages 9 , 10 , 11 , 12 , including neurons 13 , cardiomyocytes 14 and blood progenitors 15 ; however, it remains unclear whether these lineage-converted cells could repair damaged tissues in vivo . Here we demonstrate the direct induction of functional hepatocyte-like (iHep) cells from mouse tail-tip fibroblasts by transduction of Gata4, Hnf1α and Foxa3, and inactivation of p19 Arf . iHep cells show typical epithelial morphology, express hepatic genes and acquire hepatocyte functions. Notably, transplanted iHep cells repopulate the livers of fumarylacetoacetate-hydrolase-deficient ( Fah −/− ) mice and rescue almost half of recipients from death by restoring liver functions. Our study provides a novel strategy to generate functional hepatocyte-like cells for the purpose of liver engineering and regenerative medicine.

Xue and colleagues show that the transcription factors Tcf1 and Lef1 suppress CD4 + T lineage genes in CD8 + T cells through intrinsic histone deacetylase (HDAC) activity. The CD4 + and CD8 + T cell dichotomy is essential for effective cellular immunity. How individual T cell identity is established remains poorly understood. Here we show that the high-mobility group (HMG) transcription factors Tcf1 and Lef1 are essential for repressing CD4 + lineage–associated genes including Cd4 , Foxp3 and Rorc in CD8 + T cells. Tcf1- and Lef1-deficient CD8 + T cells exhibit histone hyperacetylation, which can be ascribed to intrinsic histone deacetylase (HDAC) activity in Tcf1 and Lef1. Mutation of five conserved amino acids in the Tcf1 HDAC domain diminishes HDAC activity and the ability to suppress CD4 + lineage genes in CD8 + T cells. These findings reveal that sequence-specific transcription factors can utilize intrinsic HDAC activity to guard cell identity by repressing lineage-inappropriate genes.

Innate lymphoid cells (ILCs) play important functions in immunity and tissue homeostasis, but their development is poorly understood. Through the use of single-cell approaches, we examined the transcriptional and functional heterogeneity of ILC progenitors, and studied the precursor–product relationships that link the subsets identified. This analysis identified two successive stages of ILC development within T cell factor 1-positive (TCF-1 + ) early innate lymphoid progenitors (EILPs), which we named ‘specified EILPs’ and ‘committed EILPs’. Specified EILPs generated dendritic cells, whereas this potential was greatly decreased in committed EILPs. TCF-1 was dispensable for the generation of specified EILPs, but required for the generation of committed EILPs. TCF-1 used a pre-existing regulatory landscape established in upstream lymphoid precursors to bind chromatin in EILPs. Our results provide insight into the mechanisms by which TCF-1 promotes developmental progression of ILC precursors, while constraining their dendritic cell lineage potential and enforcing commitment to ILC fate. Bhandoola and colleagues show that the transcription factor TCF-1 restrains the dendritic cell lineage potential in innate lymphoid cell progenitors.

Repetitive exposure to antigen in chronic infection and cancer drives T cell exhaustion, limiting adaptive immunity. In contrast, aberrant, sustained T cell responses can persist over decades in human allergic disease. To understand these divergent outcomes, we employed bioinformatic, immunophenotyping and functional approaches with human diseased tissues, identifying an abundant population of type 2 helper T (T H 2) cells with co-expression of TCF7 and LEF1 , and features of chronic activation. These cells, which we termed T H 2-multipotent progenitors (T H 2-MPP) could self-renew and differentiate into cytokine-producing effector cells, regulatory T (T reg ) cells and follicular helper T (T FH ) cells. Single-cell T-cell-receptor lineage tracing confirmed lineage relationships between T H 2-MPP, T H 2 effectors, T reg cells and T FH cells. T H 2-MPP persisted despite in vivo IL-4 receptor blockade, while thymic stromal lymphopoietin (TSLP) drove selective expansion of progenitor cells and rendered them insensitive to glucocorticoid-induced apoptosis in vitro. Together, our data identify T H 2-MPP as an aberrant T cell population with the potential to sustain type 2 inflammation and support the paradigm that chronic T cell responses can be coordinated over time by progenitor cells. Kratchmarov et al. identified a GATA3 + T H 2 population that expresses the transcription factors TCF1 and LEF1 and sustains type 2 inflammation in tissues over a human lifetime, despite chronic antigen exposure.

Normal cells become cancer cells after a malignant transformation, but whether cancer cells can be reversed to normal status remains elusive. Here, we report that the combination of hepatocyte nuclear factor 1A (HNF1A), HNF4A and forkhead box protein A3 (FOXA3) synergistically reprograms hepatocellular carcinoma (HCC) cells to hepatocyte-like cells (reprogrammed hepatocytes, rHeps). Our results show that rHeps lose the malignant phenotypes of cancer cells and retrieve hepatocyte-specific characteristics including hepatocyte-like morphology; global expression pattern of genes and specific biomarkers of hepatocytes; and the unique hepatic functions of albumin (ALB) secretion, glycogen synthesis, low-density lipoprotein (LDL) uptake, urea production, cytochrome P450 enzymes induction and drug metabolism. Intratumoral injection of these three factors efficiently shrank patient-derived tumor xenografts and reprogrammed HCC cells in vivo. Most importantly, transplantation of rHeps in the liver of fumarylacetoacetate hydrolase-deficient (Fah−/−) mice led to the reconstruction of hepatic lobules and the restoration of hepatic function. Mechanistically, exogenous expression of HNF1A, HNF4A and FOXA3 in HCC cells initiated the endogenous expression of numerous hepatocyte nuclear factors, which promoted the conversion of HCC cells to hepatocyte-like cells. Collectively, our results indicate the successful conversion of hepatoma cells to hepatocyte-like cells, not only extending our current knowledge of cell reprogramming but also providing a route towards a novel therapeutic strategy for cancer.