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1.  Effects of hepatocyte nuclear factor-1A and -4A on pancreatic stone protein/regenerating protein and C-reactive protein gene expression: implications for maturity-onset diabetes of the young 
Background
There is a significant clinical overlap between patients with hepatocyte nuclear factor (HNF)-1A and HNF4A maturity-onset diabetes of the young (MODY), two forms of monogenic diabetes. HNF1A and HNF4A are transcription factors that control common and partly overlapping sets of target genes. We have previously shown that elevated serum pancreatic stone protein / regenerating protein A (PSP/reg1A) levels can be detected in subjects with HNF1A-MODY. In this study, we investigated whether PSP/reg is differentially regulated by HNF1A and HNF4A.
Methods
Quantitative real-time PCR (qPCR) and Western blotting were used to validate gene and protein expression in cellular models of HNF1A- and HNF4A-MODY. Serum PSP/reg1A levels and high-sensitivity C-reactive protein (hsCRP) were measured by ELISA in 31 HNF1A- and 9 HNF4A-MODY subjects. The two groups were matched for age, body mass index, diabetes duration, blood pressure, lipid profile and aspirin and statin use.
Results
Inducible repression of HNF1A and HNF4A function in INS-1 cells suggested that PSP/reg induction required HNF4A, but not HNF1A. In contrast, crp gene expression was significantly reduced by repression of HNF1A, but not HNF4A function. PSP/reg levels were significantly lower in HNF4A subjects when compared to HNF1A subjects [9.25 (7.85-12.85) ng/ml vs. 12.5 (10.61-17.87) ng/ml, U-test P = 0.025]. hsCRP levels were significantly lower in HNF1A-MODY [0.22 (0.17-0.35) mg/L] compared to HNF4A-MODY group [0.81 (0.38-1.41) mg/L, U-test P = 0.002], Parallel measurements of serum PSP/reg1A and hsCRP levels were able to discriminate HNF1A- and HNF4A-MODY subjects.
Conclusion
Our study demonstrates that two distinct target genes, PSP/reg and crp, are differentially regulated by HNF1A and HNF4A, and provides clinical proof-of-concept that serum PSP/reg1A and hsCRP levels may distinguish HNF1A-MODY from HNF4A-MODY subjects.
doi:10.1186/1479-5876-11-156
PMCID: PMC3707779  PMID: 23803251
HNF1A; HNF4A; MODY; PSP/reg; HsCRP; Gene regulation
2.  INS-1 Cells Undergoing Caspase-Dependent Apoptosis Enhance the Regenerative Capacity of Neighboring Cells 
Diabetes  2010;59(11):2799-2808.
OBJECTIVE
In diabetes, β-cell mass is not static but in a constant process of cell death and renewal. Inactivating mutations in transcription factor 1 (tcf-1)/hepatocyte nuclear factor1a (hnf1a) result in decreased β-cell mass and HNF1A–maturity onset diabetes of the young (HNF1A-MODY). Here, we investigated the effect of a dominant-negative HNF1A mutant (DN-HNF1A) induced apoptosis on the regenerative capacity of INS-1 cells.
RESEARCH DESIGN AND METHODS
DN-HNF1A was expressed in INS-1 cells using a reverse tetracycline-dependent transactivator system. Gene(s)/protein(s) involved in β-cell regeneration were investigated by real-time quantitative RT-PCR, Western blotting, and immunohistochemistry. Pancreatic stone protein/regenerating protein (PSP/reg) serum levels in human subjects were detected by enzyme-linked immunosorbent assay.
RESULTS
We detected a prominent induction of PSP/reg at the gene and protein level during DN-HNF1A–induced apoptosis. Elevated PSP/reg levels were also detected in islets of transgenic HNF1A-MODY mice and in the serum of HNF1A-MODY patients. The induction of PSP/reg was glucose dependent and mediated by caspase activation during apoptosis. Interestingly, the supernatant from DN-HNF1A–expressing cells, but not DN-HNF1A–expressing cells treated with zVAD.fmk, was sufficient to induce PSP/reg gene expression and increase cell proliferation in naïve, untreated INS-1 cells. Further experiments demonstrated that annexin-V–positive microparticles originating from apoptosing INS-1 cells mediated the induction of PSP/reg. Treatment with recombinant PSP/reg reversed the phenotype of DN-HNF1A–induced cells by stimulating cell proliferation and increasing insulin gene expression.
CONCLUSIONS
Our results suggest that apoptosing INS-1 cells shed microparticles that may stimulate PSP/reg induction in neighboring cells, a mechanism that may facilitate the recovery of β-cell mass in HNF1A-MODY.
doi:10.2337/db09-1478
PMCID: PMC2963538  PMID: 20682686
3.  Macrosomia and Hyperinsulinaemic Hypoglycaemia in Patients with Heterozygous Mutations in the HNF4A Gene 
PLoS Medicine  2007;4(4):e118.
Background
Macrosomia is associated with considerable neonatal and maternal morbidity. Factors that predict macrosomia are poorly understood. The increased rate of macrosomia in the offspring of pregnant women with diabetes and in congenital hyperinsulinaemia is mediated by increased foetal insulin secretion. We assessed the in utero and neonatal role of two key regulators of pancreatic insulin secretion by studying birthweight and the incidence of neonatal hypoglycaemia in patients with heterozygous mutations in the maturity-onset diabetes of the young (MODY) genes HNF4A (encoding HNF-4α) and HNF1A/TCF1 (encoding HNF-1α), and the effect of pancreatic deletion of Hnf4a on foetal and neonatal insulin secretion in mice.
Methods and Findings
We examined birthweight and hypoglycaemia in 108 patients from families with diabetes due to HNF4A mutations, and 134 patients from families with HNF1A mutations. Birthweight was increased by a median of 790 g in HNF4A-mutation carriers compared to non-mutation family members (p < 0.001); 56% (30/54) of HNF4A-mutation carriers were macrosomic compared with 13% (7/54) of non-mutation family members (p < 0.001). Transient hypoglycaemia was reported in 8/54 infants with heterozygous HNF4A mutations, but was reported in none of 54 non-mutation carriers (p = 0.003). There was documented hyperinsulinaemia in three cases. Birthweight and prevalence of neonatal hypoglycaemia were not increased in HNF1A-mutation carriers. Mice with pancreatic β-cell deletion of Hnf4a had hyperinsulinaemia in utero and hyperinsulinaemic hypoglycaemia at birth.
Conclusions
HNF4A mutations are associated with a considerable increase in birthweight and macrosomia, and are a novel cause of neonatal hypoglycaemia. This study establishes a key role for HNF4A in determining foetal birthweight, and uncovers an unanticipated feature of the natural history of HNF4A-deficient diabetes, with hyperinsulinaemia at birth evolving to decreased insulin secretion and diabetes later in life.
HNF4A mutations were found to be associated with a considerable increase in birthweight and macrosomia, and were a cause of neonatal hypoglycaemia.
Editors' Summary
Background.
MODY, or maturity-onset diabetes of the young, is a particular subtype of diabetes; only a few percent of people with diabetes are thought to have this subtype. The condition comes about as a result of a mutation in one of six genes. Generally, people with MODY have high glucose (sugar) levels in the blood, and the typical symptoms of diabetes, such as increased thirst and urination, typically develop when the person is below the age of 25 y. Two of the genes that are known to cause MODY are mutant forms of HNF4A and HNF1A. The proteins that are encoded by these two genes control insulin levels produced by the pancreas; when these genes are mutated, not enough insulin is produced. Without enough insulin to control blood sugar, levels rise, leading to the symptoms of diabetes. However, MODY can be managed by many of the same interventions as other types of diabetes, such as diet, exercise, drug treatments, and insulin injections.
Why Was This Study Done?
Although the evidence shows that individuals who carry mutations in HNF4A and HNF1A do not produce enough insulin and therefore have higher glucose levels in their blood, there were some tantalizing suggestions from mouse experiments that this might not be the whole story. Specifically, the researchers suspected that during embryonic development, mutations in HNF4A or HNF1A might actually cause higher insulin levels. Too much insulin during development of a fetus is known to cause it to gain weight, resulting in a baby that is larger than the average size for its age. Larger babies are risky for both the baby and the mother. The researchers doing this study wanted to understand more precisely what the links were between the forms of MODY caused by HNF4A and HNF1A mutations, and birth-weight and blood-sugar levels.
What Did the Researchers Do and Find?
In this study, the researchers examined 15 families in which some family members had MODY caused by a mutation in HNF4A. They compared the birthweight for family members carrying the mutation (54 people) against the birthweight for those who did not (54 people). A similar comparison was done for 38 families in which some members had a different form of MODY, this time caused by a mutation in HNF1A. The results showed that the birthweight of family members who carried a mutation in HNF4A was, on average, 790 g higher than the birthweight of family members who didn't carry the mutation. Low blood-sugar levels at birth were also more common in people carrying the HNF4A mutation as compared to people who did not. However, the HNF1A mutation did not seem to be associated with greater birthweight or low blood-sugar levels at birth. Finally, in order to understand these findings further, the researchers created embryonic mice carrying mutations in the mouse equivalent of HNF4A. These embryos produced more insulin than normal mouse embryos and, after birth, were more likely to have low blood-sugar levels.
What Do These Findings Mean?
These findings show that there is a link between mutations in HNF4A, but not in HNF1A, and increased birthweight. The increase found in this study is quite substantial (a median weight of 4,660 g in the affected babies; a birthweight of more than 4,000 g is generally considered large). The results suggest that in human embryos with a mutated form of HNF4A, too much insulin is produced during development, causing faster growth and a higher chance of the baby being born with low blood-sugar levels. This is an unexpected finding, because later in life the HNF4A mutation causes lower insulin levels. Therefore, the biochemical pathways causing this type of MODY seem to be quite complicated, and further research will need to be done to fully understand them. Crucially, the research also suggests that pregnant women carrying HNF4A mutations should be closely followed to check their baby's growth and minimize the chance of complications. Doctors and families should also consider doing a genetic test for HNF4A if a baby has low blood-sugar levels and if there is a family history of diabetes; this would increase the chance of diagnosing MODY early.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed 0040118.
In a related Perspective in PLoS Medicine, Benjamin Glaser discusses causes of type 2 diabetes mellitus in the context of this study's findings
The US National Institute of Diabetes and Digestive and Kidney Diseases has pages of information on different types of diabetes
Wikipedia has an entry on Maturity Onset Diabetes of the Young (MODY) (note that Wikipedia is an internet encyclopedia that anyone can edit)
Diabetes Research Department, Peninsula Medical School, Exeter, UK provides information for patients and doctors on genetic types of diabetes; the website is maintained by the research group carrying out this study
Information from the Centers for Disease Control and Prevention on diabetes and pregnancy
doi:10.1371/journal.pmed.0040118
PMCID: PMC1845156  PMID: 17407387
4.  Circulating CD36 Is Reduced in HNF1A-MODY Carriers 
PLoS ONE  2013;8(9):e74577.
Introduction
Premature atherosclerosis is a significant cause of morbidity and mortality in type 2 diabetes mellitus. Maturity onset diabetes of the young (MODY) accounts for approximately 2% of all diabetes, with mutations in the transcription factor; hepatocyte nuclear factor 1 alpha (HNF1A) accounting for the majority of MODY cases. There is somewhat limited data available on the prevalence of macrovascular disease in HNF1A-MODY carriers with diabetes. Marked insulin resistance and the associated dyslipidaemia are not clinical features of HNF1A-MODY carriers. The scavenger protein CD36 has been shown to play a substantial role in the pathogenesis of atherosclerosis, largely through its interaction with oxidised LDL. Higher levels of monocyte CD36 and plasma CD36(sCD36) are seen to cluster with insulin resistance and diabetes. The aim of this study was to determine levels of sCD36 in participants with HNF1A-MODY diabetes and to compare them with unaffected normoglycaemic family members and participants with type 2 diabetes mellitus.
Methods
We recruited 37 participants with HNF1A-MODY diabetes and compared levels of sCD36 with BMI-matched participants with type 2 diabetes mellitus and normoglycaemic HNF1A-MODY negative family controls. Levels of sCD36 were correlated with phenotypic and biochemical parameters.
Results
HNF1A-MODY participants were lean, normotensive, with higher HDL and lower triglyceride levels when compared to controls and participants with type 2 diabetes mellitus. sCD36 was also significantly lower in HNF1A-MODY participants when compared to both the normoglycaemic family controls and to lean participants with type 2 diabetes mellitus.
Conclusion
In conclusion, sCD36 is significantly lower in lean participants with HNF1A-MODY diabetes when compared to weight-matched normoglycaemic familial HNF1A-MODY negative controls and to lean participants with type 2 diabetes mellitus. Lower levels of this pro-atherogenic marker may result from the higher HDL component in the lipid profile of HNF1A-MODY participants.
doi:10.1371/journal.pone.0074577
PMCID: PMC3771933  PMID: 24069322
5.  Hepatic function in a family with a nonsense mutation (R154X) in the hepatocyte nuclear factor-4alpha/MODY1 gene. 
Journal of Clinical Investigation  1997;100(6):1400-1405.
Maturity-onset diabetes of the young (MODY) is a genetically heterogeneous monogenic disorder characterized by autosomal dominant inheritance, onset usually before 25 yr of age, and abnormal pancreatic beta-cell function. Mutations in the hepatocyte nuclear factor(HNF)-4alpha/MODY1, glucokinase/MODY2, and HNF-1alpha/MODY3 genes can cause this form of diabetes. In contrast to the glucokinase and HNF-1alpha genes, mutations in the HNF-4alpha gene are a relatively uncommon cause of MODY, and our understanding of the MODY1 form of diabetes is based on studies of only a single family, the R-W pedigree. Here we report the identification of a second family with MODY1 and the first in which there has been a detailed characterization of hepatic function. The affected members of this family, Dresden-11, have inherited a nonsense mutation, R154X, in the HNF-4alpha gene, and are predicted to have reduced levels of this transcription factor in the tissues in which it is expressed, including pancreatic islets, liver, kidney, and intestine. Subjects with the R154X mutation exhibited a diminished insulin secretory response to oral glucose. HNF-4alpha plays a central role in tissue-specific regulation of gene expression in the liver, including the control of synthesis of proteins involved in cholesterol and lipoprotein metabolism and the coagulation cascade. Subjects with the R154X mutation, however, showed no abnormalities in lipid metabolism or coagulation except for a paradoxical 3.3-fold increase in serum lipoprotein(a) levels, nor was there any evidence of renal dysfunction in these subjects. The results suggest that MODY1 is primarily a disorder of beta-cell function.
PMCID: PMC508318  PMID: 9294105
6.  Metabolite Profiling Reveals Normal Metabolic Control in Carriers of Mutations in the Glucokinase Gene (MODY2) 
Diabetes  2013;62(2):653-661.
Mutations in the gene encoding glucokinase (GCK) cause a mild hereditary form of diabetes termed maturity-onset diabetes of the young (MODY)2 or GCK-MODY. The disease does not progress over time, and diabetes complications rarely develop. It has therefore been suggested that GCK-MODY represents a metabolically compensated condition, but experimental support for this notion is lacking. Here, we profiled metabolites in serum from patients with MODY1 (HNF4A), MODY2 (GCK), MODY3 (HNF1A), and type 2 diabetes and from healthy individuals to characterize metabolic perturbations caused by specific mutations. Analysis of four GCK-MODY patients revealed a metabolite pattern similar to that of healthy individuals, while other forms of diabetes differed markedly in their metabolite profiles. Furthermore, despite elevated glucose concentrations, carriers of GCK mutations showed lower levels of free fatty acids and triglycerides than healthy control subjects. The metabolite profiling was confirmed by enzymatic assays and replicated in a cohort of 11 GCK-MODY patients. Elevated levels of fatty acids are known to associate with β-cell dysfunction, insulin resistance, and increased incidence of late complications. Our results show that GCK-MODY represents a metabolically normal condition, which may contribute to the lack of late complications and the nonprogressive nature of the disease.
doi:10.2337/db12-0827
PMCID: PMC3554352  PMID: 23139355
7.  Evaluation of Serum 1,5 Anhydroglucitol Levels as a Clinical Test to Differentiate Subtypes of Diabetes 
Diabetes Care  2010;33(2):252-257.
OBJECTIVE
Assignment of the correct molecular diagnosis in diabetes is necessary for informed decisions regarding treatment and prognosis. Better clinical markers would facilitate discrimination and prioritization for genetic testing between diabetes subtypes. Serum 1,5 anhydroglucitol (1,5AG) levels were reported to differentiate maturity-onset diabetes of the young due to HNF1A mutations (HNF1A-MODY) from type 2 diabetes, but this requires further validation. We evaluated serum 1,5AG in a range of diabetes subtypes as an adjunct for defining diabetes etiology.
RESEARCH DESIGN AND METHODS
1,5AG was measured in U.K. subjects with: HNF1A-MODY (n = 23), MODY due to glucokinase mutations (GCK-MODY, n = 23), type 1 diabetes (n = 29), latent autoimmune diabetes in adults (LADA, n = 42), and type 2 diabetes (n = 206). Receiver operating characteristic curve analysis was performed to assess discriminative accuracy of 1,5AG for diabetes etiology.
RESULTS
Mean (SD range) 1,5AG levels were: GCK-MODY 13.06 μg/ml (5.74–29.74), HNF1A-MODY 4.23 μg/ml (2.12–8.44), type 1 diabetes 3.09 μg/ml (1.45–6.57), LADA 3.46 μg/ml (1.42–8.45), and type 2 diabetes 5.43 (2.12–13.23). Levels in GCK-MODY were higher than in other groups (P < 10−4 vs. each group). HNF1A-MODY subjects showed no difference in unadjusted 1,5AG levels from type 2 diabetes, type 1 diabetes, and LADA. Adjusting for A1C revealed a difference between HNF1A-MODY and type 2 diabetes (P = 0.001). The discriminative accuracy of unadjusted 1,5AG levels was 0.79 for GCK-MODY versus type 2 diabetes and 0.86 for GCK-MODY versus HNF1A-MODY but was only 0.60 for HNF1A-MODY versus type 2 diabetes.
CONCLUSIONS
In our dataset, serum 1,5AG performed well in discriminating GCK-MODY from other diabetes subtypes, particularly HNF1A-MODY. Measurement of 1,5AG levels could inform decisions regarding MODY diagnostic testing.
doi:10.2337/dc09-1246
PMCID: PMC2809258  PMID: 19933992
8.  High-Sensitivity CRP Discriminates HNF1A-MODY From Other Subtypes of Diabetes 
Diabetes Care  2011;34(8):1860-1862.
OBJECTIVE
Maturity-onset diabetes of the young (MODY) as a result of mutations in hepatocyte nuclear factor 1-α (HNF1A) is often misdiagnosed as type 1 diabetes or type 2 diabetes. Recent work has shown that high-sensitivity C-reactive protein (hs-CRP) levels are lower in HNF1A-MODY than type 1 diabetes, type 2 diabetes, or glucokinase (GCK)-MODY. We aim to replicate these findings in larger numbers and other MODY subtypes.
RESEARCH DESIGN AND METHODS
hs-CRP levels were assessed in 750 patients (220 HNF1A, 245 GCK, 54 HNF4-α [HNF4A], 21 HNF1-β (HNF1B), 53 type 1 diabetes, and 157 type 2 diabetes).
RESULTS
hs-CRP was lower in HNF1A-MODY (median [IQR] 0.3 [0.1–0.6] mg/L) than type 2 diabetes (1.40 [0.60–3.45] mg/L; P < 0.001) and type 1 diabetes (1.10 [0.50–1.85] mg/L; P < 0.001), HNF4A-MODY (1.45 [0.46–2.88] mg/L; P < 0.001), GCK-MODY (0.60 [0.30–1.80] mg/L; P < 0.001), and HNF1B-MODY (0.60 [0.10–2.8] mg/L; P = 0.07). hs-CRP discriminated HNF1A-MODY from type 2 diabetes with hs-CRP <0.75 mg/L showing 79% sensitivity and 70% specificity (receiver operating characteristic area under the curve = 0.84).
CONCLUSIONS
hs-CRP levels are lower in HNF1A-MODY than other forms of diabetes and may be used as a biomarker to select patients for diagnostic HNF1A genetic testing.
doi:10.2337/dc11-0323
PMCID: PMC3142017  PMID: 21700917
9.  Apolipoprotein M can discriminate HNF1A-MODY from Type 1 diabetes 
Aims
Missed diagnosis of maturity-onset diabetes of the young (MODY) has led to an interest in biomarkers that enable efficient prioritization of patients for definitive molecular testing. Apolipoprotein M (apoM) was suggested as a biomarker for hepatocyte nuclear factor 1 alpha (HNF1A)-MODY because of its reduced expression in Hnf1a−/− mice. However, subsequent human studies examining apoM as a biomarker have yielded conflicting results. We aimed to evaluate apoM as a biomarker for HNF1A-MODY using a highly specific and sensitive ELISA.
Methods
ApoM concentration was measured in subjects with HNF1A-MODY (n = 69), Type 1 diabetes (n = 50), Type 2 diabetes (n = 120) and healthy control subjects (n = 100). The discriminative accuracy of apoM and of the apoM/HDL ratio for diabetes aetiology was evaluated.
Results
Mean (standard deviation) serum apoM concentration (μmol/l) was significantly lower for subjects with HNF1A-MODY [0.86 (0.29)], than for those with Type 1 diabetes [1.37 (0.26), P = 3.1 × 10−18) and control subjects [1.34 (0.22), P = 7.2 × 10−19). There was no significant difference in apoM concentration between subjects with HNF1A-MODY and Type 2 diabetes [0.89 (0.28), P = 0.13]. The C-statistic measure of discriminative accuracy for apoM was 0.91 for HNF1A-MODY vs. Type 1 diabetes, indicating high discriminative accuracy. The apoM/HDL ratio was significantly lower in HNF1A-MODY than other study groups. However, this ratio did not perform well in discriminating HNF1A-MODY from either Type 1 diabetes (C-statistic = 0.79) or Type 2 diabetes (C-statistic = 0.68).
Conclusions
We confirm an earlier report that serum apoM levels are lower in HNF1A-MODY than in controls. Serum apoM provides good discrimination between HNF1A-MODY and Type 1 diabetes and warrants further investigation for clinical utility in diabetes diagnostics.
doi:10.1111/dme.12066
PMCID: PMC4193536  PMID: 23157689
10.  Cystatin C is not a good candidate biomarker for HNF1A-MODY 
Acta Diabetologica  2012;50(5):815-820.
Cystatin C is a marker of glomerular filtration rate (GFR). Its level is influenced, among the others, by CRP whose concentration is decreased in HNF1A-MODY. We hypothesized that cystatin C level might be altered in HNF1A-MODY. We aimed to evaluate cystatin C in HNF1A-MODY both as a diagnostic marker and as a method of assessing GFR. We initially examined 51 HNF1A-MODY patients, 56 subjects with type 1 diabetes (T1DM), 39 with type 2 diabetes (T2DM) and 43 non-diabetic individuals (ND) from Poland. Subjects from two UK centres were used as replication panels: including 215 HNF1A-MODY, 203 T2DM, 39 HNF4A-MODY, 170 GCK-MODY, 17 HNF1B-MODY and 58 T1DM patients. The data were analysed with additive models, adjusting for gender, age, BMI and estimated GFR (creatinine). In the Polish subjects, adjusted cystatin C level in HNF1A-MODY was lower compared with T1DM, T2DM and ND (p < 0.05). Additionally, cystatin C-based GFR was higher than that calculated from creatinine level (p < 0.0001) in HNF1A-MODY, while the two GFR estimates were similar or cystatin C-based lower in the other groups. In the UK subjects, there were no differences in cystatin C between HNF1A-MODY and the other diabetic subgroups, except HNF1B-MODY. In UK HNF1A-MODY, cystatin C-based GFR estimate was higher than the creatinine-based one (p < 0.0001). Concluding, we could not confirm our hypothesis (supported by the Polish results) that cystatin C level is altered by HNF1A mutations; thus, it cannot be used as a biomarker for HNF1A-MODY. In HNF1A-MODY, the cystatin C-based GFR estimate is higher than the creatinine-based one.
doi:10.1007/s00592-012-0378-1
PMCID: PMC3898131  PMID: 22350134
Monogenic diabetes; MODY; Cystatin C; HNF1A
11.  Metabolic Profiling in Maturity-Onset Diabetes of the Young (MODY) and Young Onset Type 2 Diabetes Fails to Detect Robust Urinary Biomarkers 
PLoS ONE  2012;7(7):e40962.
It is important to identify patients with Maturity-onset diabetes of the young (MODY) as a molecular diagnosis determines both treatment and prognosis. Genetic testing is currently expensive and many patients are therefore not assessed and are misclassified as having either type 1 or type 2 diabetes. Biomarkers could facilitate the prioritisation of patients for genetic testing. We hypothesised that patients with different underlying genetic aetiologies for their diabetes could have distinct metabolic profiles which may uncover novel biomarkers. The aim of this study was to perform metabolic profiling in urine from patients with MODY due to mutations in the genes encoding glucokinase (GCK) or hepatocyte nuclear factor 1 alpha (HNF1A), type 2 diabetes (T2D) and normoglycaemic control subjects. Urinary metabolic profiling by Nuclear Magnetic Resonance (NMR) and ultra performance liquid chromatography hyphenated to Q-TOF mass spectrometry (UPLC-MS) was performed in a Discovery set of subjects with HNF1A-MODY (n = 14), GCK-MODY (n = 17), T2D (n = 14) and normoglycaemic controls (n = 34). Data were used to build a valid partial least squares discriminate analysis (PLS-DA) model where HNF1A-MODY subjects could be separated from the other diabetes subtypes. No single metabolite contributed significantly to the separation of the patient groups. However, betaine, valine, glycine and glucose were elevated in the urine of HNF1A-MODY subjects compared to the other subgroups. Direct measurements of urinary amino acids and betaine in an extended dataset did not support differences between patients groups. Elevated urinary glucose in HNF1A-MODY is consistent with the previously reported low renal threshold for glucose in this genetic subtype. In conclusion, we report the first metabolic profiling study in monogenic diabetes and show that, despite the distinct biochemical pathways affected, there are unlikely to be robust urinary biomarkers which distinguish monogenic subtypes from T2D. Our results have implications for studies investigating metabolic profiles in complex traits including T2D.
doi:10.1371/journal.pone.0040962
PMCID: PMC3408469  PMID: 22859960
12.  Systematic Assessment of Etiology in Adults With a Clinical Diagnosis of Young-Onset Type 2 Diabetes Is a Successful Strategy for Identifying Maturity-Onset Diabetes of the Young 
Diabetes Care  2012;35(6):1206-1212.
OBJECTIVE
Misdiagnosis of maturity-onset diabetes of the young (MODY) remains widespread, despite the benefits of optimized management. This cross-sectional study examined diagnostic misclassification of MODY in subjects with clinically labeled young adult-onset type 1 and type 2 diabetes by extending genetic testing beyond current guidelines.
RESEARCH DESIGN AND METHODS
Individuals were selected for diagnostic sequencing if they displayed features atypical for their diagnostic label. From 247 case subjects with clinically labeled type 1 diabetes, we sequenced hepatocyte nuclear factor 1 α (HNF1A) and hepatocyte nuclear factor 4 α (HNF4A) in 20 with residual β-cell function ≥3 years from diagnosis (random or glucagon-stimulated C-peptide ≥0.2 nmol/L). From 322 with clinically labeled type 2 diabetes, we sequenced HNF1A and HNF4A in 80 with diabetes diagnosed ≤30 years and/or diabetes diagnosed ≤45 years without metabolic syndrome. We also sequenced the glucokinase (GCK) in 40 subjects with mild fasting hyperglycemia.
RESULTS
In the type 1 diabetic group, two HNF1A mutations were found (0.8% prevalence). In type 2 diabetic subjects, 10 HNF1A, two HNF4A, and one GCK mutation were identified (4.0%). Only 47% of MODY case subjects identified met current guidelines for diagnostic sequencing. Follow-up revealed a further 12 mutation carriers among relatives. Twenty-seven percent of newly identified MODY subjects changed treatment, all with improved glycemic control (HbA1c 8.8 vs. 7.3% at 3 months; P = 0.02).
CONCLUSIONS
The systematic use of widened diagnostic testing criteria doubled the numbers of MODY case subjects identified compared with current clinical practice. The yield was greatest in young adult-onset type 2 diabetes. We recommend that all patients diagnosed before age 30 and with presence of C-peptide at 3 years' duration are considered for molecular diagnostic analysis.
doi:10.2337/dc11-1243
PMCID: PMC3357216  PMID: 22432108
13.  Assessment of High-Sensitivity C-Reactive Protein Levels as Diagnostic Discriminator of Maturity-Onset Diabetes of the Young Due to HNF1A Mutations 
Diabetes Care  2010;33(9):1919-1924.
OBJECTIVE
Despite the clinical importance of an accurate diagnosis in individuals with monogenic forms of diabetes, restricted access to genetic testing leaves many patients with undiagnosed diabetes. Recently, common variation near the HNF1 homeobox A (HNF1A) gene was shown to influence C-reactive protein levels in healthy adults. We hypothesized that serum levels of high-sensitivity C-reactive protein (hs-CRP) could represent a clinically useful biomarker for the identification of HNF1A mutations causing maturity-onset diabetes of the young (MODY).
RESEARCH DESIGN AND METHODS
Serum hs-CRP was measured in subjects with HNF1A-MODY (n = 31), autoimmune diabetes (n = 316), type 2 diabetes (n = 240), and glucokinase (GCK) MODY (n = 24) and in nondiabetic individuals (n = 198). The discriminative accuracy of hs-CRP was evaluated through receiver operating characteristic (ROC) curve analysis, and performance was compared with standard diagnostic criteria. Our primary analyses excluded ∼11% of subjects in whom the single available hs-CRP measurement was >10 mg/l.
RESULTS
Geometric mean (SD range) hs-CRP levels were significantly lower (P ≤ 0.009) for HNF1A-MODY individuals, 0.20 (0.03–1.14) mg/l, than for any other group: autoimmune diabetes 0.58 (0.10–2.75) mg/l, type 2 diabetes 1.33 (0.28–6.14) mg/l, GCK-MODY 1.01 (0.19–5.33) mg/l, and nondiabetic 0.48 (0.10–2.42) mg/l. The ROC-derived C-statistic for discriminating HNF1A-MODY and type 2 diabetes was 0.8. Measurement of hs-CRP, either alone or in combination with current diagnostic criteria, was superior to current diagnostic criteria alone. Sensitivity and specificity for the combined criteria approached 80%.
CONCLUSIONS
Serum hs-CRP levels are markedly lower in HNF1A-MODY than in other forms of diabetes. hs-CRP has potential as a widely available, cost-effective screening test to support more precise targeting of MODY diagnostic testing.
doi:10.2337/dc10-0288
PMCID: PMC2928334  PMID: 20724646
14.  Clinical Application of 1,5-Anhydroglucitol Measurements in Patients with Hepatocyte Nuclear Factor-1α Maturity-Onset Diabetes of the Young  
Diabetes Care  2008;31(8):1496-1501.
OBJECTIVE—1,5-anhydroglucitol (1,5-AG) is a short-term marker of metabolic control in diabetes. Its renal loss is stimulated in hyperglycemic conditions by glycosuria, which results in a lowered plasma concentration. As a low renal threshold for glucose has been described in hepatocyte nuclear factor-1α (HNF-1α) maturity-onset diabetes of the young (MODY), the 1,5-AG level may be altered in these patients. The purpose of this study was to assess the 1,5-AG levels in patients with HNF-1α MODY and in type 2 diabetic subjects with a similar degree of metabolic control. In addition, we aimed to evaluate this particle as a biomarker for HNF-1α MODY.
RESEARCH DESIGN AND METHODS—We included 33 diabetic patients from the Polish Nationwide Registry of MODY. In addition, we examined 43 type 2 diabetic patients and 47 nondiabetic control subjects. The 1,5-AG concentration was measured with an enzymatic assay (GlycoMark). Receiver operating characteristic (ROC) curve analysis was used to evaluate 1,5-AG as a screening marker for HNF-1α MODY.
RESULTS—The mean 1,5-AG plasma concentration in diabetic HNF-1α mutation carriers was 5.9 μg/ml, and it was lower than that in type 2 diabetic patients (11.0 μg/ml, P = 0.003) and in nondiabetic control subjects (23.9 μg/ml, P < 0.00005). The ROC curve analysis revealed 85.7% sensitivity and 80.0% specificity of 1,5-AG in screening for HNF-1α MODY at the criterion of <6.5 μg/ml in patients with an A1C level between 6.5 and 9.0%.
CONCLUSIONS—1,5-AG may be a useful biomarker for differential diagnosis of patients with HNF-1α MODY with a specific range of A1C, although this requires further investigation. However, the clinical use of this particle in diabetic HNF-1α mutation carriers for metabolic control has substantial limitations.
doi:10.2337/dc07-2334
PMCID: PMC2494661  PMID: 18492944
15.  The transcription factor HNF1α induces expression of angiotensin-converting enzyme 2 (ACE2) in pancreatic islets from evolutionarily conserved promoter motifs 
Biochimica et biophysica acta  2013;1829(11):10.1016/j.bbagrm.2013.09.007.
Pancreatic angiotensin-converting enzyme 2 (ACE2) has previously been shown to be critical for maintaining glycemia and β-cell function. Efforts to maintain or increase ACE2 expression in pancreatic β-cells might therefore have therapeutic potential for treating diabetes. In our study, we investigated the transcriptional role of hepatocyte nuclear factor 1α (HNF1α) and hepatocyte nuclear factor 1β (HNF1β) in induction of ACE2 expression in insulin-secreting cells. A deficient allele of HNF1α or HNF1β causes maturity-onset diabetes of the young (MODY) types 3 and 5, respectively, in humans. We found that ACE2 is primarily transcribed from the proximal part of the ACE2 promoter in the pancreas. In the proximal part of the human ACE2 promoter, we further identified three functional HNF1 binding sites, as they have binding affinity for HNF1α and HNF1β and are required for induction of promoter activity by HNF1β in insulinoma cells. These three sites are well-conserved among mammalian species. Both HNF1α and HNF1β induce expression of ACE2 mRNA and lead to elevated levels of ACE2 protein and ACE2 enzymatic activity in insulinoma cells. Furthermore, HNF1α dose-dependently increases ACE2 expression in primary pancreatic islet cells. We conclude that HNF1α can induce the expression of ACE2 in pancreatic islet cells via evolutionarily conserved HNF1 binding sites in the ACE2 promoter. Potential therapeutics aimed at counteracting functional HNF1α depletion in diabetes and MODY3 will thus have ACE2 induction in pancreatic islets as a likely beneficial effect.
doi:10.1016/j.bbagrm.2013.09.007
PMCID: PMC3838857  PMID: 24100303
Renin angiotensin system; pancreatic islets; promoter; transcriptional regulation; ACE2; HNF1α
16.  Clinically-Defined Maturity Onset Diabetes of the Young in Omanis 
Objectives
We are seeing a progressive increase in the number of young patients with clinically defined maturity onset diabetes of the young (MODY) having a family history suggestive of a monogenic cause of their disease and no evidence of autoimmune type 1 diabetes mellitus (T1DM). The aim of this study was to determine whether or not mutations in the 3 commonest forms of MODY, hepatic nuclear factor 4α (HNF4α), HNF1α and glucokinase (GK), are a cause of diabetes in young Omanis.
Methods
The study was performed at Sultan Qaboos University Hospital (SQUH), Oman. Twenty young diabetics with a family history suggestive of monogenic inheritance were identified in less than 18 months; the median age of onset of diabetes was 25 years and the median body mass index (BMI) 29 at presentation. Screening for the presence of autoimmune antibodies against pancreatic beta cells islet cell antibody (ICA) and glutamic acid decarboxylase (GAD) was negative. Fourteen of them consented to genetic screening and their blood was sent to Prof. A. Hattersley’s Unit at the Peninsular Medical School, Exeter, UK. There, their DNA was screened for known mutations by sequencing exon 1–10 of the GCK and exon 2–10 of the HNF1α and HNF4α genes, the three commonest forms of MODY in Europe.
Results
Surprisingly, none of the patients had any of the tested MODY mutations.
Conclusion
In this small sample of patients with clinically defined MODY, mutations of the three most commonly affected genes occurring in Caucasians were not observed. Either these patients have novel MODY mutations or have inherited a high proportion of the type 2 diabetes mellitus (T2DM) susceptibility genes compounded by excessive insulin resistance due to obesity.
PMCID: PMC3074660  PMID: 21509085
Diabetes Mellitus; Type II; Diabetes mellitus; maturity onset; MODY; mutations; Diabetes; familial; Young adults; Oman
17.  Mutations in HNF1A Result in Marked Alterations of Plasma Glycan Profile 
Diabetes  2013;62(4):1329-1337.
A recent genome-wide association study identified hepatocyte nuclear factor 1-α (HNF1A) as a key regulator of fucosylation. We hypothesized that loss-of-function HNF1A mutations causal for maturity-onset diabetes of the young (MODY) would display altered fucosylation of N-linked glycans on plasma proteins and that glycan biomarkers could improve the efficiency of a diagnosis of HNF1A-MODY. In a pilot comparison of 33 subjects with HNF1A-MODY and 41 subjects with type 2 diabetes, 15 of 29 glycan measurements differed between the two groups. The DG9-glycan index, which is the ratio of fucosylated to nonfucosylated triantennary glycans, provided optimum discrimination in the pilot study and was examined further among additional subjects with HNF1A-MODY (n = 188), glucokinase (GCK)-MODY (n = 118), hepatocyte nuclear factor 4-α (HNF4A)-MODY (n = 40), type 1 diabetes (n = 98), type 2 diabetes (n = 167), and nondiabetic controls (n = 98). The DG9-glycan index was markedly lower in HNF1A-MODY than in controls or other diabetes subtypes, offered good discrimination between HNF1A-MODY and both type 1 and type 2 diabetes (C statistic ≥0.90), and enabled us to detect three previously undetected HNF1A mutations in patients with diabetes. In conclusion, glycan profiles are altered substantially in HNF1A-MODY, and the DG9-glycan index has potential clinical value as a diagnostic biomarker of HNF1A dysfunction.
doi:10.2337/db12-0880
PMCID: PMC3609552  PMID: 23274891
18.  Examination of Rare Variants in HNF4 α in European Americans with Type 2 Diabetes 
Journal of diabetes & metabolism  2011;2(145):1000145.
The hepatocyte nuclear factor 4-α (HNF4α) gene codes for a transcription factor which is responsible for regulating gene transcription in pancreatic beta cells, in addition to its primary role in hepatic gene regulation. Mutations in this gene can lead to maturity-onset diabetes of the young (MODY), an uncommon, autosomal dominant, non-insulin dependent form of diabetes. Mutations in HNF4α have been found in few individuals, and infrequently have they segregated completely with MODY in families. In addition, due to similarity of phenotypes, it is unclear what proportion of type 2 diabetes (T2DM) in the general population is due to MODY or HNF4α mutations specifically. In this study, 27 documented rare and common variants were genotyped in a European American population of 1270 T2DM cases and 1017 controls from review of databases and literature implicating HNF4α variants in MODY and T2DM. Seventeen variants were found to be monomorphic. Two cases and one control subject had one copy of a 6-bp P2 promoter deletion. The intron 1 variant (rs6103716; MAF = 0.31) was not significantly associated with disease status (p>0.8) and the missense variant Thr130Ile (rs1800961; MAF = 0.027) was also not significantly different between cases and controls (p>0.2), but showed a trend consistent with association with T2DM. Four variants were found to be rare as heterozygotes in small numbers of subjects. Since many variants were infrequent, a pooled chi-squared analysis of rare variants was used to assess the overall burden of variants between cases and controls. This analysis revealed no significant difference (P=0.22). We conclude there is little evidence to suggest that HNF4α variants contribute significantly to risk of T2DM in the general population, but a modest contribution cannot be excluded. In addition, the observation of some mutations in controls suggests they are not highly penetrant MODY-causing variants.
doi:10.4172/2155-6156.1000145
PMCID: PMC3515062  PMID: 23227446
Type 2 Diabetes; HNF4A; Rare variants
19.  Mild fasting hyperglycemia in children: high rate of glucokinase mutations and some risk of developing type 1 diabetes mellitus 
Pediatric diabetes  2009;10(6):382-388.
Background
Incidental hyperglycemia in children generates concern about the presence of preclinical type 1 diabetes mellitus (T1DM).
Objective
To genetically evaluate two common forms of maturity-onset diabetes of youth (MODY), the short-term prognosis in children with mild hyperglycemia, and a positive family history of diabetes mellitus.
Subjects
Asymptomatic children and adolescents (n = 14), younger than 15 yr, with fasting hyperglycemia, a positive family history of mild non-progressive hyperglycemia, and negative pancreatic autoantibodies were studied.
Patients and methods
Glucokinase gene (GCK) and hepatocyte nuclear factor 1 alpha gene (HNF1A) causing two common forms of MODY were sequenced. The clinical outcome was evaluated after a follow-up period of 2.8 ± 1.3 yr.
Results
GCK mutations were present in seven children. The confirmation of this diagnosis allowed discontinuation of insulin in two families and oral medications in three families. Mutations of HNF1A were not detected in any of the families. During the follow-up period, all the GCK mutation carrier children remained asymptomatic without medication and the last hemoglobin A1c levels were 6.4 ± 0.7%. In the GCK-negative children (n = 7), one developed T1DM, corresponding to 7.2% of the total group. Mild fasting hyperglycemia persisted during follow-up in four GCK-negative children and normalized in the remaining two.
Conclusions
The presence of mild persistent hyperglycemia in any patient without autoantibodies should lead to genetic analysis of GCK, particularly if there is a positive family history. Furthermore, those without GCK mutations should be followed with repeat autoantibody testing, and other genetic types of diabetes should be considered if hyperglycemia worsens.
doi:10.1111/j.1399-5448.2009.00499.x
PMCID: PMC2864306  PMID: 19309449
DM; genetics; glucokinase; hyperglycemia; incidental hyperglycemia; MODY; prognosis
20.  Pancreatic stone protein as an early biomarker predicting mortality in a prospective cohort of patients with sepsis requiring ICU management 
Critical Care  2012;16(4):R114.
Introduction
Biomarkers, such as C-reactive protein [CRP] and procalcitonin [PCT], are insufficiently sensitive or specific to stratify patients with sepsis. We investigate the prognostic value of pancreatic stone protein/regenerating protein (PSP/reg) concentration in patients with severe infections.
Methods
PSP/reg, CRP, PCT, tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL1-β), IL-6 and IL-8 were prospectively measured in cohort of patients ≥ 18 years of age with severe sepsis or septic shock within 24 hours of admission in a medico-surgical intensive care unit (ICU) of a community and referral university hospital, and the ability to predict in-hospital mortality was determined.
Results
We evaluated 107 patients, 33 with severe sepsis and 74 with septic shock, with in-hospital mortality rates of 6% (2/33) and 25% (17/74), respectively. Plasma concentrations of PSP/reg (343.5 vs. 73.5 ng/ml, P < 0.001), PCT (39.3 vs. 12.0 ng/ml, P < 0.001), IL-8 (682 vs. 184 ng/ml, P < 0.001) and IL-6 (1955 vs. 544 pg/ml, P < 0.01) were significantly higher in patients with septic shock than with severe sepsis. Of note, median PSP/reg was 13.0 ng/ml (IQR: 4.8) in 20 severely burned patients without infection. The area under the ROC curve for PSP/reg (0.65 [95% CI: 0.51 to 0.80]) was higher than for CRP (0.44 [0.29 to 0.60]), PCT 0.46 [0.29 to 0.61]), IL-8 (0.61 [0.43 to 0.77]) or IL-6 (0.59 [0.44 to 0.75]) in predicting in-hospital mortality. In patients with septic shock, PSP/reg was the only biomarker associated with in-hospital mortality (P = 0.049). Risk of mortality increased continuously for each ascending quartile of PSP/reg.
Conclusions
Measurement of PSP/reg concentration within 24 hours of ICU admission may predict in-hospital mortality in patients with septic shock, identifying patients who may benefit most from tailored ICU management.
doi:10.1186/cc11406
PMCID: PMC3580689  PMID: 22748193
21.  Whole-Exome Sequencing and High Throughput Genotyping Identified KCNJ11 as the Thirteenth MODY Gene 
PLoS ONE  2012;7(6):e37423.
Background
Maturity-onset of the young (MODY) is a clinically heterogeneous form of diabetes characterized by an autosomal-dominant mode of inheritance, an onset before the age of 25 years, and a primary defect in the pancreatic beta-cell function. Approximately 30% of MODY families remain genetically unexplained (MODY-X). Here, we aimed to use whole-exome sequencing (WES) in a four-generation MODY-X family to identify a new susceptibility gene for MODY.
Methodology
WES (Agilent-SureSelect capture/Illumina-GAIIx sequencing) was performed in three affected and one non-affected relatives in the MODY-X family. We then performed a high-throughput multiplex genotyping (Illumina-GoldenGate assay) of the putative causal mutations in the whole family and in 406 controls. A linkage analysis was also carried out.
Principal Findings
By focusing on variants of interest (i.e. gains of stop codon, frameshift, non-synonymous and splice-site variants not reported in dbSNP130) present in the three affected relatives and not present in the control, we found 69 mutations. However, as WES was not uniform between samples, a total of 324 mutations had to be assessed in the whole family and in controls. Only one mutation (p.Glu227Lys in KCNJ11) co-segregated with diabetes in the family (with a LOD-score of 3.68). No KCNJ11 mutation was found in 25 other MODY-X unrelated subjects.
Conclusions/Significance
Beyond neonatal diabetes mellitus (NDM), KCNJ11 is also a MODY gene (‘MODY13’), confirming the wide spectrum of diabetes related phenotypes due to mutations in NDM genes (i.e. KCNJ11, ABCC8 and INS). Therefore, the molecular diagnosis of MODY should include KCNJ11 as affected carriers can be ideally treated with oral sulfonylureas.
doi:10.1371/journal.pone.0037423
PMCID: PMC3372463  PMID: 22701567
22.  Less but better: cardioprotective lipid profile of patients with GCK-MODY despite lower HDL cholesterol level 
Acta Diabetologica  2014;51(4):625-632.
Patients with diabetes caused by single-gene mutations generally exhibit an altered course of diabetes. Those with mutations of the glucokinase gene (GCK-MODY) show good metabolic control and low risk of cardiovascular complications despite paradoxically lowered high-density lipoprotein (HDL) cholesterol levels. In order to investigate the matter, we analyzed the composition of low-density lipoprotein (LDL) and HDL subpopulations in such individuals. The LipoPrint© system (Quantimetrix, USA) based on non-denaturing, linear polyacrylamide gel electrophoresis was used to separate and measure LDL and HDL subclasses in fresh-frozen serum samples from patients with mutations of glucokinase or HNF1A, type 1 diabetes (T1DM) and healthy controls. Fresh serum samples from a total of 37 monogenic diabetes patients (21 from GCK-MODY and 16 from HNF1A-MODY), 22 T1DM patients and 15 healthy individuals were measured in this study. Concentrations of the small, highly atherogenic LDL subpopulation were similar among the compared groups. Large HDL percentage was significantly higher in GCK-MODY than in control (p = 0.0003), T1DM (p = 0.0006) and HNF1A-MODY groups (p = 0.0246). Patients with GCK-MODY were characterized by significantly lower intermediate HDL levels than controls (p = 0.0003) and T1DM (p = 0.0005). Small, potentially atherogenic HDL content differed significantly with the GCK-MODY group showing concentrations of that subfraction from control (p = 0.0096), T1DM (p = 0.0193) and HNF1A-MODY (p = 0.0057) groups. Within-group heterogeneity suggested the existence of potential gene–gene or gene–environment interactions. GCK-MODY is characterized by a strongly protective profile of HDL cholesterol subpopulations. A degree of heterogeneity within the groups suggests the existence of interactions with other genetic or clinical factors.
doi:10.1007/s00592-014-0567-1
PMCID: PMC4127439  PMID: 24549415
MODY; Monogenic diabetes; Lipid subpopulations
23.  SRC-1 and GRIP1 Coactivate Transcription with Hepatocyte Nuclear Factor 4* 
The Journal of biological chemistry  1998;273(47):30847-30850.
Hepatocyte nuclear factor-4 (HNF4), a member of the nuclear receptor superfamily, plays an important role in tissue-specific gene expression, including genes involved in hepatic glucose metabolism. In this study, we show that SRC-1 and GRIP1, which act as coactivators for various nuclear receptors, associate with HNF4 in vivo and enhance its transactivation potential. The AF-2 domain of HNF4 is required for this interaction and for the potentiation of transcriptional activity by these co-activators. p300 can also serve as a coactivator with HNF4, and it synergizes with SRC-1 to further augment the activity of HNF4. HNF4 is also a key regulator of the expression of hepatocyte nuclear factor-1 (HNF1). The overexpression of SRC-1 or GRIP1 enhances expression from a HNF1 gene promoter-reporter in HepG2 hepatoma cells, and this requires an intact HNF4-binding site in the HNF1 gene promoter. Type 1 maturity onset diabetes of young (MODY), which is characterized by abnormal glucose-mediated insulin secretion, is caused by mutations of the HNF4 gene. A mutation of the HNF4-binding site in the HNF1 gene promoter has also been associated with MODY. Thus, HNF4 is involved in the regulation of glucose homeostasis at several levels and along with the SRC-1, GRIP1, and p300 may play an important role in the pathophysiology of non-insulin-dependent diabetes mellitus.
PMCID: PMC3968904  PMID: 9812974
24.  Expression and localization of P1 promoter-driven hepatocyte nuclear factor-4α (HNF4α) isoforms in human and rats 
Nuclear Receptor  2003;1:5.
Background
Hepatocyte nuclear factor-4α (HNF4α; NR2A1) is an orphan member of the nuclear receptor superfamily involved in various processes that could influence endoderm development, glucose and lipid metabolism. A loss-of-function mutation in human HNF4α causes one form of diabetes mellitus called maturity-onset diabetes of the young type 1 (MODY1) which is characterized in part by a diminished insulin secretory response to glucose. The expression of HNF4α in a variety of tissues has been examined predominantly at the mRNA level, and there is little information regarding the cellular localization of the endogenous HNF4α protein, due, in part, to the limited availability of human HNF4α-specific antibodies.
Results
Monoclonal antibodies have been produced using baculovirus particles displaying gp64-HNF4α fusion proteins as the immunizing agent. The mouse anti-human HNF4α monoclonal antibody (K9218) generated against human HNF4α1/α2/α3 amino acids 3–49 was shown to recognize not only the transfected and expressed P1 promoter-driven HNF4α proteins, but also endogenous proteins. Western blot analysis with whole cell extracts from Hep G2, Huh7 and Caco-2 showed the expression of HNF4α protein, but HEK293 showed no expression of HNF4α protein. Nuclear-specific localization of the HNF4α protein was observed in the hepatocytes of liver cells, proximal tubular epithelial cells of kidney, and mucosal epithelial cells of small intestine and colon, but no HNF4α protein was detected in the stomach, pancreas, glomerulus, and distal and collecting tubular epithelial cells of kidney. The same tissue distribution of HNF4α protein was observed in humans and rats. Electron microscopic immunohistochemistry showed a chromatin-like localization of HNF4α in the liver and kidney. As in the immunohistochemical investigation using K9218, HNF4α mRNA was found to be localized primarily to liver, kidney, small intestine and colon by RT-PCR and GeneChip analysis.
Conclusion
These results suggest that this method has the potential to produce valuable antibodies without the need for a protein purification step. Immunohistochemical studies indicate the tissue and subcellular specific localization of HNF4α and demonstrate the utility of K9218 for the detection of P1 promoter-driven HNF4α isoforms in humans and in several other mammalian species.
doi:10.1186/1478-1336-1-5
PMCID: PMC194242  PMID: 12952540
25.  Localization of hepatocyte nuclear factor‐4α in the nucleolus and nucleus is regulated by its C‐terminus 
Abstract
Aims/Introduction:  Mutations in hepatocyte nuclear factor‐4α (HNF4α) lead to various diseases, among which C‐terminal deletions of HNF4α are exclusively responsible for maturity onset diabetes of the young 1 (MODY1). MODY is an autosomal dominant disease characterized by a primary defect in insulin response to glucose, suggesting that the C‐terminus of HNF4α is important for pancreatic β‐cell function. To clarify the role of the C‐terminus of HNF4α, changes in cellular localization and the binding ability to its regulator were examined, specifically in the region containing Q268, which deletion causes MODY1.
Materials and Methods:  Cellular localization of mutant HNF4α were examined in monkey kidney 7 (COS7), Chinese hamster ovary, rat insulinoma and mouse insulinoma cells, and their binding activity to other proteins were examined by fluorescence resonance energy transfer (FRET) in COS7 cells.
Results:  Although wild‐type HNF4α was localized in the nucleoplasm in transfected cultured cells, Q268X‐HNF4α was located predominantly in the nucleolus. Deletion analysis of the C‐terminus of HNF4α showed that the S337X‐HNF4α mutant, and other mutants with shorter amino acid sequences (S337‐K194), were mostly localized in the nucleolus. HNF4α mutants with amino acid sequences shorter than the W192X‐HNF4α mutant gradually spread to the nucleoplasm in accordance with their lengths. The A250X‐HNF4α mutant was capable of causing the accumulation of HNF4α or the small heterodimer partner (SHP), one of the HNF4α regulators, in the nucleolus. However, the R154X‐HNF4α mutant did not have binding ability to wild‐type HNF4α or SHP, and thus was seen in the nucleus.
Conclusions:  The C‐terminus sites might play a key role in facilitating the nucleolar and subnucleolar localization of HNF4α. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2012.00210.x, 2012)
doi:10.1111/j.2040-1124.2012.00210.x
PMCID: PMC4019245  PMID: 24843605
Fluorescence resonance energy transfer; Hepatocyte nuclear factor‐4α; Nucleolus

Results 1-25 (1016448)