Renal malformations may be linked to mutations in the hepatocyte nuclear factor-1alpha (MODY3) gene

Role of HNFA1 Gene Variants in Pancreatic Beta Cells Function and Glycaemic Control in Young Individuals with Type 1 Diabetes

The HNF1A transcription factor, implicated in the regulation of pancreatic beta cells, as well as in glucose and lipid metabolism, is responsible for type 3 maturity-onset diabetes of the young (MODY3). HNF1A is also involved in increased susceptibility to polygenic forms of diabetes, such as type 2 diabetes (T2D) and gestational diabetes (GD), while its possible role in type 1 diabetes (T1D) is not known. In this study, 277 children and adolescents with T1D and 140 healthy controls were recruited. The following SNPs in HNF1A gene were selected: rs1169286, rs1169288, rs7979478, and rs2259816. Through linear or logistic regression analysis, we analyzed their association with T1D susceptibility and related clinical traits, such as insulin dose-adjusted glycated hemoglobin A1c (IDAA1c) and glycated hemoglobin (HbA1c). We found that rs1169286 was associated with IDAA1c and HbA1c values (p-value = 0.0027 and p-value = 0.0075, respectively), while rs1169288 was associated with IDAA1c (p-value = 0.0081). No association between HNF1A SNPs and T1D development emerged. In conclusion, our findings suggest for the first time that HNF1A variants may be a risk factor for beta cell function and glycaemic control in T1D individuals.

HNF1A Mutations and Beta Cell Dysfunction in Diabetes

Understanding the genetic factors of diabetes is essential for addressing the global increase in type 2 diabetes. HNF1A mutations cause a monogenic form of diabetes called maturity-onset diabetes of the young (MODY), and HNF1A single-nucleotide polymorphisms are associated with the development of type 2 diabetes. Numerous studies have been conducted, mainly using genetically modified mice, to explore the molecular basis for the development of diabetes caused by HNF1A mutations, and to reveal the roles of HNF1A in multiple organs, including insulin secretion from pancreatic beta cells, lipid metabolism and protein synthesis in the liver, and urinary glucose reabsorption in the kidneys. Recent studies using human stem cells that mimic MODY have provided new insights into beta cell dysfunction. In this article, we discuss the involvement of HNF1A in beta cell dysfunction by reviewing previous studies using genetically modified mice and recent findings in human stem cell-derived beta cells.

HNF1A：From Monogenic Diabetes to Type 2 Diabetes and Gestational Diabetes Mellitus

Diabetes, a disease characterized by hyperglycemia, has a serious impact on the lives and families of patients as well as on society. Diabetes is a group of highly heterogeneous metabolic diseases that can be classified as type 1 diabetes (T1D), type 2 diabetes (T2D), gestational diabetes mellitus (GDM), or other according to the etiology. The clinical manifestations are more or less similar among the different types of diabetes, and each type is highly heterogeneous due to different pathogenic factors. Therefore, distinguishing between various types of diabetes and defining their subtypes are major challenges hindering the precise treatment of the disease. T2D is the main type of diabetes in humans as well as the most heterogeneous. Fortunately, some studies have shown that variants of certain genes involved in monogenic diabetes also increase the risk of T2D. We hope this finding will enable breakthroughs regarding the pathogenesis of T2D and facilitate personalized treatment of the disease by exploring the function of the signal genes involved. Hepatocyte nuclear factor 1 homeobox A (HNF1α) is widely expressed in pancreatic β cells, the liver, the intestines, and other organs. HNF1α is highly polymorphic, but lacks a mutation hot spot. Mutations can be found at any site of the gene. Some single nucleotide polymorphisms (SNPs) cause maturity-onset diabetes of the young type 3 (MODY3) while some others do not cause MODY3 but increase the susceptibility to T2D or GDM. The phenotypes of MODY3 caused by different SNPs also differ. MODY3 is among the most common types of MODY, which is a form of monogenic diabetes mellitus caused by a single gene mutation. Both T2D and GDM are multifactorial diseases caused by both genetic and environmental factors. Different types of diabetes mellitus have different clinical phenotypes and treatments. This review focuses on HNF1α gene polymorphisms, HNF1A-MODY3, HNF1A-associated T2D and GDM, and the related pathogenesis and treatment methods. We hope this review will provide a valuable reference for the precise and individualized treatment of diabetes caused by abnormal HNF1α by summarizing the clinical heterogeneity of blood glucose abnormalities caused by HNF1α mutation.

A case of digenic maturity onset diabetes of the young with heterozygous variants in both HNF1Α and HNF1Β genes

BACKGROUND

Maturity onset diabetes of the young (MODY) is the most commonly reported form of monogenic diabetes in the pediatric population. Only a few cases of digenic MODY have been reported up to now.

CASE REPORT

A female patient was diagnosed with diabetes at the age of 7 years and was treated with insulin. A strong family history of diabetes was present in the maternal side of the family. The patient also presented hypomagnesemia, glomerulocystic kidney disease and a bicornuate uterus. Genetic testing of the patient revealed that she was a double heterozygous carrier of HNF1A gene variant c.685C > T; (p.Arg229Ter) and a whole gene deletion of the HNF1B gene. Her mother was a carrier of the same HNF1A variant.

CONCLUSION

Digenic inheritance of MODY pathogenic variants is probably more common than currently reported in literature. The use of Next Generation Sequencing panels in testing strategies for MODY could unmask such cases that would otherwise remain undiagnosed.

The spectrum of HNF1A gene mutations in patients with MODY 3 phenotype and identification of three novel germline mutations in Turkish Population

BACKGROUND

Maturity-onset diabetes of the young (MODY) is a monogenic form of diabetes mellitus characterized by autosomal dominant inheritance, early age of onset, and pancreatic beta cell dysfunction. Heterozygous mutations in several genes may cause MODY.

METHODS

In the present study, we investigated the molecular spectrum of HNF1A (hepatocyte nuclear factor 1a) mutations, in the individuals referred to a reference center for molecular genetic analysis. Mutations screening was performed in a group of 136 unrelated patients (average age 17.22 years) selected by clinical characterization of MODY. Mutation screening involved direct sequencing of the HNF1A gene.

RESULTS

Among 136 individuals analyzed, 10 were carrying heterozygous HNF1A mutations, 3 of them being novel. Clinical features, such as age of diabetes at diagnosis or severity of hyperglycemia, were not related to the mutation type or location. No clear phenotype - genotype correlations were identified.

CONCLUSIONS

As a conclusion MODY resulted from HNF1A mutations shows heterogeneity at both phenotypic and molecular levels in Turkish population.

Genetic markers of inflammation may not contribute to metabolic traits in Mexican children

Background: Low-grade chronic inflammation is a common feature of obesity and its cardio-metabolic complications. However, little is known about a possible causal role of inflammation in metabolic disorders. Mexico is among the countries with the highest obesity rates in the world and the admixed Mexican population is a relevant sample due to high levels of genetic diversity.

Methods: Here, we studied 1,462 Mexican children recruited from Mexico City. Six genetic variants in five inflammation-related genes were genotyped: rs1137101 (leptin receptor (LEPR)), rs7305618 (hepatocyte nuclear factor 1 alpha (HNF1A)), rs1800629 (tumor necrosis factor alpha (TNFA)), rs1800896, rs1800871 (interleukin-10 (IL-10)), rs1862513 (resistin (RETN)). Ten continuous and eight binary traits were assessed. Linear and logistic regression models were used adjusting for age, sex, and recruitment centre.

Results: We found that one SNP displayed a nominal evidence of association with a continuous trait: rs1800871 (IL-10) with LDL (beta = −0.068 ± 1.006, P = 0.01). Subsequently, we found one nominal association with a binary trait: rs7305618 (HNF1A) with family history of hypertension (odds-ratio = 1.389 [1.054–1.829], P = 0.02). However, no P-value passed the Bonferroni correction for multiple testing.

Discussion: Our data in a Mexican children population are consistent with previous reports in European adults in failing to demonstrate an association between inflammation-associated single nucleotide polymorphisms (SNPs) and metabolic traits.

Tubular proteinuria in patients with HNF1α mutations: HNF1α drives endocytosis in the proximal tubule

Hepatocyte nuclear factor 1α (HNF1α) is a transcription factor expressed in the liver, pancreas, and proximal tubule of the kidney. Mutations of HNF1α cause an autosomal dominant form of diabetes mellitus (MODY-HNF1A) and tubular dysfunction. To gain insights into the role of HNF1α in the proximal tubule, we analyzed Hnf1a-deficient mice. Compared with wild-type littermates, Hnf1a knockout mice showed low-molecular-weight proteinuria and a 70% decrease in the uptake of β2-microglobulin, indicating a major endocytic defect due to decreased expression of megalin/cubilin receptors. We identified several binding sites for HNF1α in promoters of Lrp2 and Cubn genes encoding megalin and cubilin, respectively. The functional interaction of HNF1α with these promoters was shown in C33 epithelial cells lacking endogenous HNF1α. Defective receptor-mediated endocytosis was confirmed in proximal tubule cells from these knockout mice and could be rescued by transfection of wild-type but not mutant HNF1α. Transfection of human proximal tubule HK2 cells with HNF1α was able to upregulate megalin and cubilin expression and to increase endocytosis of albumin. Low-molecular-weight proteinuria was consistently detected in individuals with HNF1A mutations compared with healthy controls and patients with non-MODY-HNF1A diabetes mellitus. Thus, HNF1α plays a key role in the constitutive expression of megalin and cubilin, hence regulating endocytosis in the proximal tubule of the kidney. These findings provide new insight into the renal phenotype of individuals with mutations of HNF1A.

Cystatin C is not a good candidate biomarker for HNF1A-MODY

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.

Dipeptidyl peptidase-IV inhibitors are efficient adjunct therapy in HNF1A maturity-onset diabetes of the young patients--report of two cases

BACKGROUND

In HNF1A maturity-onset diabetes of the young (MODY), sulfonylurea (SU) is the first-line treatment. Over time, such therapy fails, and additional treatment is required. Dipeptidyl peptidase IV (DPP-IV) inhibitors are new agents that lower blood glucose by prolonging the activity of circulating incretins.

METHODS

We applied DPP-IV inhibitors in two HNF1A MODY patients whose earlier therapeutic regimen included SU.

RESULTS

Case 1, a 39-year-old woman, a carrier of the ArgR171X HNF1A mutation, with a 7-year history of diabetes was on 160 mg of gliclazide and 2,000 mg of metformin. Her initial hemoglobin A1c (HbA1c) level was 7.2%, while the mean glucose level on the CGMS((R)) (Medtronic, Northridge, CA) record was 162 mg/dL. Sitagliptine, in a dose of 100 mg/day, was added to the previous treatment. Case 2, a 62-year-old woman, a carrier of the IVS7nt-6G>A mutation, with a 41-year history of diabetes was treated with 240 mg/day gliclazide and 6 IU of insulin/day. Her initial HbA1c was 8.8%, and average glycemia reached 172 mg/dL. In her case, we started the combined therapy with 50 mg of vildagliptine twice daily. Patients were reexamined after 3 months, and HbA1c fell to 6.3% in both subjects. Similarly, significant improvement in glycemic control on CGMS was observed as the average glycemia decreased to 114 mg/dL and 134 mg/dL in Case 1 and Case 2, respectively. No episodes of hypoglycemia or other side effects were recorded. As intravenous glucose tolerance tests (IVGTTs) were performed before and after DPP-IV implementation, we were able to assess their impact on insulin secretion under fasting conditions. We saw a substantial rise in insulin level increment during IVGTT (by 9.8 and13.4 mIU/L in Case 1 and Case 2, respectively).

CONCLUSIONS

DPP-IV inhibitors may be an effective tool of combined therapy in HNF1A MODY, and they seem to improve beta-cell function under fasting conditions.

Can geneticists help clinicians to understand and treat non-autoimmune diabetes?

Approximately, a few percent of the European population suffers from diabetes. Scientific evidence showed that specific treatment of this disease could be successfully tailored on the basis of proper differential diagnosis that in many instances also requires genetic testing. This may be helpful in achieving metabolic control of the disease, increasing quality of life and potentially reducing the prevalence of chronic complications. Identification of the molecular background of these specific forms of diabetes gives new insight into the underlying aetiology. This knowledge helps to optimize treatment in specific clinical situations. Monogenic diabetes is an excellent example of a clinical area where new advances in molecular genetics can aid patient care and treatment decisions. The most frequently diagnosed forms of monogenic diabetes are MODY, mitochondrial diabetes, permanent and transient neonatal diabetes (PNDM and TNDM). These rare forms probably constitute at least a few percent of all diabetes cases seen in diabetic clinics. The proper differential diagnosis also helps to predict the progress of diabetes in affected individuals and defines the prognosis in the family. Recently, several genome wide association studies added new facts to the knowledge on complex forms of type 2 diabetes mellitus (T2DM) as the scientists substantially extended the short list of previously identified genes. Most newly identified variants influence beta-cell insulin secretion, while a few modulate peripheral insulin action. It is not clear whether in the future the genetic testing of frequent polymorphisms will influence the treatment of T2DM. In this review, we present the clinical application of genetic testing in non-autoimmune diabetes, mostly monogenic forms of disease.

Deletion of IFT20 in the mouse kidney causes misorientation of the mitotic spindle and cystic kidney disease

Primary cilia project from the surface of most vertebrate cells and are thought to be sensory organelles. Defects in primary cilia lead to cystic kidney disease, although the ciliary mechanisms that promote and maintain normal renal function remain incompletely understood. In this work, we generated a floxed allele of the ciliary assembly gene Ift20. Deleting this gene specifically in kidney collecting duct cells prevents cilia formation and promotes rapid postnatal cystic expansion of the kidney. Dividing collecting duct cells in early stages of cyst formation fail to properly orient their mitotic spindles along the tubule, whereas nondividing cells improperly position their centrosomes. At later stages, cells lacking cilia have increased canonical Wnt signaling and increased rates of proliferation. Thus, IFT20 functions to couple extracellular events to cell proliferation and differentiation.

Monogenic diabetes: implications for therapy of rare types of disease

There are two major forms of diabetes: type 1 and type 2. However, monogenic diabetes, associated with severe beta-cell dysfunction or with severe resistance to insulin action, is diagnosed with increasing frequency by genetic testing. The list of such forms of diabetes includes MODY, mitochondrial diabetes, permanent neonatal diabetes (PNDM) and transient neonatal diabetes, familial lipodystrophies and some others. These rare forms constitute probably at least a few per cent of all diabetes cases seen in diabetic clinics. The identification of the molecular background of specific forms of diabetes gives new insight into the underlying aetiology. This knowledge helps to optimize treatment in specific clinical situations. The proper differential diagnosis also helps to predict the progress of diabetes in affected individuals and defines the prognosis in the family. For example, in patients with MODY2 because of glucokinase mutations who have very mild diabetes characterized by modest fasting, hyperglycaemia diet is frequently sufficient. Some other forms of monogenic diabetes associated with impaired function of the beta-cell, such as MODY3 and PNDM linked to mutations in Kir6.2 and SUR1 genes, can be successfully managed by sulphonylurea agents. Although the examples of pharmacogenetics seem to be less spectacular in rare syndromes of insulin resistance, those patients can also benefit from genetic testing. In this paper, the aetiology of some monogenic diabetes forms is reviewed together with the clinical aspects of management of the affected individuals.

Clinical application of 1,5-anhydroglucitol measurements in patients with hepatocyte nuclear factor-1alpha maturity-onset diabetes of the young

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-1alpha (HNF-1alpha) 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-1alpha 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-1alpha 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-1alpha MODY.

RESULTS

The mean 1,5-AG plasma concentration in diabetic HNF-1alpha mutation carriers was 5.9 microg/ml, and it was lower than that in type 2 diabetic patients (11.0 microg/ml, P = 0.003) and in nondiabetic control subjects (23.9 microg/ml, P < 0.00005). The ROC curve analysis revealed 85.7% sensitivity and 80.0% specificity of 1,5-AG in screening for HNF-1alpha MODY at the criterion of <6.5 microg/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-1alpha MODY with a specific range of A1C, although this requires further investigation. However, the clinical use of this particle in diabetic HNF-1alpha mutation carriers for metabolic control has substantial limitations.

Pancreatic exocrine insufficiency is not common in HNF-1alpha MODY

AIMS

Exocrine pancreatic insufficiency has been described in Type 1 and Type 2 diabetes. The hepatocyte nuclear factor (HNF)-1alpha gene associated with maturity-onset diabetes of the young (MODY3) is expressed in several organs, including the exocrine pancreas. The aim of this study was to determine the prevalence of exocrine pancreas dysfunction in HNF-1alpha MODY patients.

METHODS

Thirty-one diabetic HNF-1alpha MODY patients (mean age 37.2 +/- 14.6 years) and 35 healthy control subjects (39.1 +/- 13.9 years) participated. In addition, 25 Type 1 diabetic (T1DM) subjects were also examined (mean age 30.6 +/- 10.1 years). Exocrine pancreas function was assessed by measurement of stool elastase 1 (E1) activity. All diabetic patients and control subjects completed a gastrointestinal (GI) symptoms questionnaire.

RESULTS

In all but two individuals, stool E1 levels were normal (> 200 microg/g). The only case of severely impaired pancreas exocrine function (E1 = 47.5 microg/g) was observed in the MODY3 group. The mean stool E1 elastase level in the HNF-1alpha MODY group was significantly lower than in the control subjects (401.0 +/- 118.4 vs. 482.7 +/- 151.1 microg/g, P = 0.001). Similarly, E1 levels in T1DM were lower than in control subjects (344.8 +/- 132.1 microg/g, P = 0.001); one patient with a moderate enzyme decrease was identified in this group. In addition, more frequent GI complaints were reported by HNF-1alpha MODY patients when compared with control subjects and also with T1DM patients.

CONCLUSION

Pancreatic exocrine insufficiency is not common in HNF-1alpha MODY diabetic patients, although their stool E1 levels are lower than in healthy control subjects.

Function of HNF1 in the pathogenesis of diabetes

The importance of hepatocyte nuclear factors (HNFs), as well as other transcription factors in β-cell development and function, was underlined by the characterization of human mutations causing maturity-onset diabetes of the young (MODY). HNF1A and HNF1B mutations lead to MODY forms 3 and 5, respectively. Thus, transcriptional control is an essential mechanism underlying the precise metabolic control exerted by β-cells in regulating insulin release. The diabetes phenotype of MODY3 (HNF1α) and the phenotypes of MODY5 (HNF1β), which can also include renal disease and genitourinary malformations, as well as neonatal diabetes and pancreatic agenesis, have now been described. However, detailed molecular pathology remains elusive. The large array of dominant-negative and deletion mutations, and the lack of structure-phenotype relationships for most mutations, have not helped us to formulate a mechanistic understanding. Further molecular studies of HNF1 actions and gene regulation are anticipated to provide useful insights into β-cell biology and potential therapeutic tools.

Evaluation of Apolipoprotein M Serum Concentration as a Biomarker of HNF-1alpha MODY

Apolipoprotein M (apoM) is a 26-kDa protein expressed mainly in the liver and kidneys. It is present predominantly in high-density lipoproteins (HDL). ApoM expression is influenced by the hepatocyte nuclear factor-1alpha (HNF-1alpha), which is a transcription factor associated with the pathogenesis of MODY. Some earlier data suggested that apoM levels were lower in the serum of HNF-1alpha MODY subjects, than in that of other diabetics and healthy controls. The aim of this study was to evaluate apoM as a biomarker for HNF-1alpha MODY. We included in this study 48 HNF-1alpha mutation carriers (40 diabetic patients and 8 subjects with normal glucose levels in the fasted state) from the Polish Nationwide Registry of MODY. In addition, we examined 55 T2DM patients and 55 apparently healthy volunteers who had normal fasting glucose levels. ApoM was measured by the sandwich dot-blot technique with recombinant apoM (Abnova) as a protein standard, mouse anti-human apoM monoclonal primary antibody and rat anti-mouse HRP-conjugated secondary antibody (BD Biosciences). Mean apoM level in the MODY group was 13.6 mug/ml, SD 1.9 (13.5 mug/ml, SD 1.7 in diabetic subjects and 13.9 mug/ml, SD 2.0 in non-diabetic mutation carriers respectively). In the T2DM group, mean apoM level was 13.7 mug/ml, SD 2.1, while it reached 13.8 mug/ml, SD 2.0 in healthy controls. There was no difference between apoM serum concentrations in all the study groups. In summary, our study showed no association between HNF-1alpha mutations resulting in MODY phenotype and apoM levels. Thus, we cannot confirm the clinical usefulness of apoM as a biomarker of HNF-1alpha MODY.

Na(+) -glucose transporter-2 messenger ribonucleic acid expression in kidney of diabetic rats correlates with glycemic levels: involvement of hepatocyte nuclear factor-1alpha expression and activity

Mutations in Na(+)-glucose transporters (SGLT)-2 and hepatocyte nuclear factor (HNF)-1alpha genes have been related to renal glycosuria and maturity-onset diabetes of the young 3, respectively. However, the expression of these genes have not been investigated in type 1 and type 2 diabetes. Here in kidney of diabetic rats, we tested the hypotheses that SGLT2 mRNA expression is altered; HNF-1alpha is involved in this regulation; and glycemic homeostasis is a related mechanism. The in vivo binding of HNF-1alpha into the SGLT2 promoter region in renal cortex was confirmed by chromatin immunoprecipitation assay. SGLT2 and HNF-1alpha mRNA expression (by Northern and RT-PCR analysis) and HNF-1 binding activity of nuclear proteins (by EMSA) were investigated in diabetic rats and treated or not with insulin or phlorizin (an inhibitor of SGLT2). Results showed that diabetes increases SGLT2 and HNF-1alpha mRNA expression (~50%) and binding of nuclear proteins to a HNF-1 consensus motif (~100%). Six days of insulin or phlorizin treatment restores these parameters to nondiabetic-rat levels. Moreover, both treatments similarly reduced glycemia, despite the differences in plasma insulin and urinary glucose concentrations, highlighting the plasma glucose levels as involved in the observed modulations. This study shows that SGLT2 mRNA expression and HNF-1alpha expression and activity correlate positively in kidney of diabetic rats. It also shows that diabetes-induced changes are reversed by lowering glycemia, independently of insulinemia. Our demonstration that HNF-1alpha binds DNA that encodes SGLT2 supports the hypothesis that HNF-1alpha, as a modulator of SGLT2 expression, may be involved in diabetic kidney disease.