The liver is a multi-functional organ that regulates major physiological processes and that possesses a remarkable regeneration capacity. After loss of functional liver mass the liver grows back to its original, individual size through hepatocyte proliferation and apoptosis. How does a single hepatocyte ‘know’ when the organ has grown to its final size? This work considers the initial growth phase of liver regeneration after partial hepatectomy in which the mass is restored. There are strong and valid arguments that the trigger of proliferation after partial hepatectomy is mediated through the portal blood flow. It remains unclear, if either or both the concentration of metabolites in the blood or the shear stress are crucial to hepatocyte proliferation and liver size control. A cell-based mathematical model is developed that helps discriminate the effects of these two potential triggers. Analysis of the mathematical model shows that a metabolic load and a hemodynamical hypothesis imply different feedback mechanisms at the cellular scale. The predictions of the developed mathematical model are compared to experimental data in rats. The assumption that hepatocytes are able to buffer the metabolic load leads to a robustness against short-term fluctuations of the trigger which can not be achieved with a purely hemodynamical trigger.

Indiana University-Purdue University Indianapolis (IUPUI) / The maternal liver shows marked growth during pregnancy to accommodate the development and metabolic needs of the placenta and fetus. Previous study has shown that the maternal liver grows proportionally to the increase in body weight during gestation by hyperplasia and hypertrophy of hepatocytes. As the maternal liver is enlarged, the transcript level of Ascl1, a transcription factor essential to progenitor cells of the central nervous system and peripheral nervous system, is highly upregulated. The aims of the study were to (1) identify hepatic Ascl1-expressing cells, and (2) study the functions of Ascl1 in maternal liver during pregnancy. In situ hybridization shows that most cell types (parenchymal, nonparenchymal, and mesothelial cells) express Ascl1 mRNA in maternal livers during gestation and in male regenerating livers. Notably, hepatic mesothelial cells abundantly express Ascl1 during pregnancy and liver regeneration. Inducible ablation of Ascl1 gene during pregnancy results in maternal liver enlargement, litter size reduction, and fetal growth retardation. In addition, maternal hepatocytes deficient in Ascl1 gene lack majority of their cytosols and exhibit β-catenin nuclear translocation, while maintaining their cellular boundary and identity. In summary, in both maternal liver during pregnancy and regenerating liver, the expression of Ascl1 is induced in most cell types. Mesothelial cells are potential origin of Ascl1-expressing cells. Ascl1 gene is essential for the progression of normal pregnancy

Indiana University-Purdue University Indianapolis (IUPUI) / MicroRNAs are small RNA molecules that regulate expression of genes involved in development, cell differentiation, proliferation and death. It has been estimated that in eukaryotes, approximately 0.5 to 1% of predicted genes encode a microRNA, which in humans, regulate at least 30% of genes at an average of 200 genes per miRNA. Some microRNAs are tissue-specific, while others are ubiquitously expressed. In liver, a few microRNAs have been identified that regulate specialized functions. The best known is miR-122, the most abundant liver-specific miRNA, which regulates cholesterol biosynthesis and other genes of fatty acid metabolism; it also regulates the cell cycle through inhibition of cyclin G1. To discover other miRNAs with relevant function in liver, we characterized miRNA profiles in normal tissue and identified miR-709. Our data indicates this is a highly abundant hepatic miRNA and is dysregulated in an animal model of type 2 diabetes. To understand its biological role, miR-709 gene targets were identified by analyzing the transcriptome of primary hepatocytes transfected with a miR-709 mimic. The genes identified fell within four main categories: cytoskeleton binding, extracellular matrix attachment, endosomal recycling and fatty acid metabolism. Thus, similar to miR-122, miR-709 downregulates genes from multiple pathways. This would be predicted, given the abundance of the miRNA and the fact that the estimated number of genes targeted by a miRNA is in the hundreds. In the case of miR-709, these suggested a coordinated response during cell proliferation, when cytoskeleton remodeling requires substantial changes in gene expression. Consistently, miR-709 was found significantly upregulated in an animal model of hepatocellular carcinoma. Likewise, in a mouse model of liver regeneration, mature miR-709 was increased. To study the consequences of depleting miR-709 in quiescent and proliferating cells, primary hepatocytes and hepatoma cells were cultured with antagomiRs (anti-miRs). The presence of anti-miR-709 caused cell death in proliferating cells. Quiescent primary hepatocytes responded by upregulating miR-709 and its host gene, Rfx1. These studies show that miR-709 targets genes relevant to cystokeleton structural genes. Thus, miR-709 and Rfx1 may be needed to facilitate cytoskeleton reorganization, a process that occurs after liver injury and repopulation, or during tumorigenesis.

Amongst its numerous functions, the liver is responsible for the synthesis and secretion of very low-density lipoprotein (VLDL). VLDL particles play the important role of facilitating the transport of lipids within the aqueous environment of the plasma; yet high plasma concentrations of these particles result in the pathogenesis of atherosclerosis, while low VLDL secretion from the liver results in hepatic steatosis. VLDL synthesis in the hepatocyte is completed in the Golgi apparatus, which serves as the final site of VLDL maturation prior to its secretion to the bloodstream. The mechanism by which VLDL’s targeted transport to the plasma membrane is facilitated has yet to be identified. Our lab has identified this entity. Our findings suggest that upon maturation, VLDL is directed to the plasma membrane through a novel trafficking vesicle, the Post-Golgi VLDL Transport Vesicle (PG-VTV). PG-VTVs containing [3H] radiolabeled VLDL were generated in a cell-free in vitro budding assay for study. First, the fusogenic capabilities of PG-VTVs were established. Vesicles were capable of fusing with the plasma membrane and delivering the VLDL cargo for secretion in a vectorial manner. The next goal of our study is to characterize key regulatory molecular entities necessary for PG-VTV biosynthesis. A detailed analysis was undertaken to determine the PG-VTV proteome via western blot and two-dimensional difference in gel electrophoresis. The identification of key molecular regulators will potentially offer therapeutic targets to control VLDL secretion to the bloodstream.

No description available.

Since its beginning, graft rejection remains the key problem of solid organ transplantation. This reaction of the recipient's immune system against mismatched antigens of the transplanted organ causes graft damage and consequently loss of its function. Rejection involves cellular (lymphocyte mediated) and humoral (antibody mediated) mechanisms. Among the genetic factors which may have a prognostic value in rejection risk evaluation are the Human Leukocyte Antigens (HLA) genotype, the Killer Immunoglobuline-like Receptor (KIR) gene repertoir, cytokine and other gene polymorphisms. These factors could be screened for before transplantation to find the best possible combination of genetic characteristics of the donor and recipient and to reveal patients with "risky" genotypes, who may need more intensive immunosuppression and more careful post-transplant follow-up. Molecular factors, such as HLA and non-HLA antibodies, soluble CD30 molecule (sCD30), Hepatocyte Growth Factor (HGF) and other cytokines, measured before and/or after transplantation in the recipient's blood may be helpful for rejection risk estimation and may also be used as post-transplant rejection onset markers. In our study, we focused on some of the above mentioned factors. We found that ethnicity plays a significant role in the...

Schilddrüsenhormone (TH) regulieren Metabolismus und Energiestoffwechsel. Der TH‐Metabolit (THM) 3,5‐T2 (3,5‐Diiod‐L‐Thyronin) aktiviert Fett‐Oxidation und mitochondriale Atmung. Der THM 3‐Iodothyronamin (3‐T1AM) beeinflusst zusätzlich glukoregulatorische Prozesse. THM können zur Reduktion von Körperfett beitragen. Um 3,5‐T2 im humanen Serum nachzuweisen sollte ein Immunoassay aufgebaut, validiert und angewendet werden. In intakten hepatozellulären (HepG2) sowie pankreatischen ß‐Zellen (MIN6) sollte untersucht werden ob THM durch Modulation der mitochondrialen Aktivität die zelluläre Substratverstoffwechslung (3,5‐T2) und Insulinsekretion (3‐T1AM) regulieren können. Der Immunoassay ist sensitiv, spezifisch und misst zuverlässig 3,5‐T2 im humanen Serum. Hyper‐ und Hypothyreose zeigen vergleichbare 3,5‐T2 Konzentrationen, jedoch akkumuliert 3,5‐T2 bei sekundären Erkrankungen der Schilddrüse und athyreoten Patienten unter Thyroxin‐Supplementation. In HepG2‐Zellen konnte die Aktivierung der mitochondrialen Atmung durch 3,3‘,5‐Triiod‐L‐Thyronin (T3), jedoch nicht durch 3,5‐T2 stimuliert werden. Die Expression von TH‐transporters (THT) war gering verglichen mit Maus‐Hepatozyten. MIN6 exprimiert THT vergleichbar mit Langerhansschen Inselzellen der Maus. 3‐T1AM wird in die Zelle aufgenommen, zu 3‐Iodothyroessigsäure (TA1) metabolisiert, und wieder exportiert. Nach 3‐T1AM Gabe ist die mitochondriale ATP‐Produktion sowie die Glukose‐stimulierte Insulinsekretion (GSIS) vermindert. 3,5‐T2 zirkuliert in euthyreoten Individuen, ist nicht an der zentralen Regulation der TH‐Achse beteiligt, wird extrathyroidal gebildet und niedrige T3‐Werte können durch erhöhtes 3,5‐T2 erklärt werden. HepG2 erwies sich als ungeeignetes Zellmodell, da wenige THT vorhanden sind, 3,5‐T2 die Plasmamembran wahrscheinlich nicht passieren kann und damit die Aktivierung der Mitochondrien aus bleibt. In MIN6 wurde gezeigt, dass die GSIS nicht ausschließlich an der Plasmamembran durch 3‐T1AM reguliert wird. / Thyroid hormones (TH) regulate metabolism and energy metabolism. The TH‐metabolite (THM) 3,5‐T2 (3,5‐diiodo‐L‐thyronine) activates fat oxidation and mitochondrial respiration. The THM 3‐T1AM (3‐iodothyronamine) influences in addition glucoregulatory processes. THM may support reduction in body fat mass. It was the idea to establish, validate and apply an immunoassay to determine 3,5‐T2 in human serum. Using intact hepatocellular (HepG2) as well as pancreatic ß‐cells (MIN6) it should be tested if THM can modulate mitochondrial activity, resulting in increased cellular substrate usage (3,5‐T2) as well as decreased insulin secreation (3‐T1AM). The established immunoassay is sensitive, specific and detects precisely 3,5‐T2 in human serum. Hyper‐ and hypothyroidism shows similar 3,5‐T2 concentrations, although 3,5‐T2 accumulates in secondary thyroidal illness as well as in athyreotic patients under thyroxine‐supplementation. Using HepG2 cells, mitochondrial respiration was stimulated by 3,3‘,5‐triiodo‐L‐thyronine (T3), but 3,5‐T2 had no effect. Expression of TH‐transporters (THT) was low compared to murine hepatocytes. In contrast, MIN6 express THT comparable to murine Langerhans islets. 3‐T1AM is taken up by the cell, metabolized to 3‐iodothyroacetic acid (TA1) and following export. After 3‐T1AM application mitochondrial ATP‐production as well as glucose‐stimulated insulin secretion (GSIS) was reduced. 3,5‐T2 circulates in euthyroid individuals, is not involved in central regulation of TH‐axis, is produced extrathyroidally and low T3 values can be explained by increased 3,5‐T2. HepG2 was shown to be an inappropriate cellmodel, because THT are merely expressed, suggesting that 3,5‐T2 is not able to pass the plasma membrane, thereby preventing mitochondrial activation. In addition, it was shown in MIN6 cells, that GSIS is not exclusively regulated at the plasma membrane level via 3‐T1AM.

Interleukin(IL)-22, ein Zytokin der IL-10-Interferon-Familie, beeinflusst die Funktion von Gewebezellen, wirkt jedoch nicht auf Immunzellen. In dieser Arbeit konnte ich zeigen, dass IL-22 in Keratinozyten nur eine begrenzte Anzahl von Genen in ihrer Expression reguliert, was eine Hemmung der terminalen Differenzierung und eine Steigerung der antimikrobiellen Abwehr und der zellulären Mobilität bewirkt. Diese IL-22-Effekte konnten in vivo aufgrund ihrer Induzierbarkeit durch eine IL-22-Behandlung in Mäusen bestätigt werden und fanden sich darüber hinaus in der läsionalen Haut von Patienten mit Psoriasis wieder. Eine pathogenetische Rolle von IL-22 bei Psoriasis wurde durch eine gefundene Erhöhung der IL-22-Spiegel im Blut dieser Patienten und eine Korrelation dieser mit dem Schweregrad der Erkrankung untermauert. Eine Untersuchung der Wirkung von IL-22 auf Hepatozyten zeigte, dass IL-22 in diesen Zellen die Produktion des LPS-Bindungsproteins (LBP) steigert, welches in hohen Konzentrationen bakterielle Bestandteile neutralisiert. In vivo zeigte sich, dass eine IL-22-Gabe in der Maus eine verstärkte Expression von LBP in der Leber und erhöhte sytemische LBP-Spiegel bewirkt. Diese Hepatozyten-spezifische IL-22-Wirkung spiegelte sich bei Patienten mit Morbus Crohn in erhöhten systemischen LBP-Spiegeln wieder. Bei der Psoriasis steht vor allem der regenerative Phänotyp der Keratinozyten, gekennzeichnet durch eine verminderte terminale Differenzierung und eine gesteigerte Mobilität, im Vordergrund und bildet die Ursache für die klinisch sichtbaren epidermalen Veränderungen. Demgegenüber könnte bei Morbus Crohn IL 22 durch die Induktion von hepatozytärem LBP zur Neutralisierung von durch die gestörte Darmbarriere ins Blut translozierte bakterielle LPS zur lokalen Begrenzung der Entzündung beitragen. Ausgehend von diesen Beobachtungen wäre eine IL-22-Neutralisierung bzw. IL-22-Applikation ein innovativer Therapieansatz für die Behandlung von Psoriasis und Morbus Crohn. / Interleukin(IL)-22, a cytokine belonging to the IL-10-Interferon-family, regulates the function of tissue cells, but not of immune cells. Here, I could show, that in keratinocytes IL-22 regulates the expression of a limited number of genes leading to an inhibition of the terminal differentiation and an increase of the antimicrobial defense and cellular mobility. These IL-22 effects were also confirmed in vivo as they could be induced in mice by IL-22-treatment and moreover, were also found to be present in the lesional skin of psoriasis patients. A pathogenetic role of IL-22 in psoriasis was substantiated by the finding that IL-22 level are elevated in the blood of these patients and correlated with the disease severity. By investigating the influence of IL-22 on hepatocytes, I found an increase of LPS-binding protein (LBP) production by IL-22, a protein which neutralizes bacterial components at high concentrations. In vivo, IL-22 treatment of mice led to a high hepatic LBP expression and elevated blood LBP level. This hepatocyte-specific IL-22 effect was reflected in patients with crohn´s disease in elevated systemic LBP level. In psoriasis, especially the regenerative phenotype of keratinocytes, characterized by the distorted terminal differentiation and enhanced mobility, is a key feature and the basis for the clinically visible epidermal alterations. In contrast, in crohn´s disease by inducing hepatic LBP production IL-22 likely contributes to the neutralisation of LPS translocated into the blood via the distorted intestinal barrier and thereby to a local limitation of inflammation. Based on these observations a neutralisation or application of IL-22 would be an innovative therapeutic approach for the treatment of psoriasis and crohn´s disease, respectively.

La thérapie cellulaire pourrait représenter une alternative à la transplantation hépatique dans certaines pathologies comme les maladies métaboliques sévères. Toutefois, la pénurie de donneurs d’organes implique la nécessité de trouver de nouvelles sources de cellules hépatiques comme les cellules souches pluripotentes qui peuvent être amplifiées extensivement et différenciées en tout type cellulaire. Les cellules souches embryonnaires humaines (hESC) et les cellules souches pluripotentes induites humaines (hiPSC) générées à partir des cellules somatiques de patients puis différenciées en hépatocytes représentent une source potentielle d’hépatocytes. Ces cellules permettent en outre d’envisager la transplantation d’hépatocytes autologues génétiquement modifiés comme alternative à la transplantation hépatique pour le traitement de certaines maladies génétiques du foie. L’hypercholestérolémie familiale (HF) est une maladie autosomale dominante due à des mutations dans le gène codant le Récepteur aux Low Density Lipoproteins (RLDL) qui est à l’origine d’un taux élevé de cholestérol sanguin de patients HF. Les patients homozygotes doivent épurer leur sérum par LDL-aphérèse en moyenne deux fois par mois dès le plus jeune âge pour éviter les infarctus mortels survenant dès l’enfance. Les hépatocytes différenciées à partir des iPSC de patients et leur correction in vitro, permettent d'évaluer la faisabilité de la transplantation d'hépatocytes autologues génétiquement modifiés pour le traitement de l’hypercholestérolémie familiale.Au cours du développement du foie, des hépatocytes et des cholangiocytes, les deux types de cellules épithéliales hépatiques, dérivent de progéniteurs hépatiques bipotents (les hépatoblastes). Bien que les cholangiocytes formant les canaux biliaires intrahépatiques ne représentent qu'une petite fraction de la population cellulaire totale du foie (3%), ces cellules régulent activement la composition de la bile par réabsorption des acides biliaires, un processus qui est important dans des maladies choléstatiques du foie. Dans la première partie de cette étude nous avons mis au point une approche de différenciation des cellules souches pluripotentes (hESC et hiPSC) en cholangiocytes fonctionnels. Ces cellules serviront à la modélisation des maladies génétiques touchant les cholangiocytes formant des canaux biliaires. Dans la deuxième partie, nous avons généré des iPSC spécifiques de patients HF (HF-iPSC), différenciées en hépatocytes et corrigé le défaut phénotypique par transfert lentiviral de l’ADNc codant le LDLR dans les HF-iPSC. / Cell therapy can be an alternative to liver transplantation in some cases such as severe metabolic diseases. However, the shortage of organ donors implies the need to find new sources of liver cells such as hepatocytes derived from pluripotent stem cells that can be amplified and differentiated extensively into any cell type. Human embryonic stem cells (hESC) and human induced pluripotent stem cells (hiPSC) generated from somatic cells of patients and then differentiated into hepatocytes represent a potential source of transplantable hepatocytes. These cells now make it possible to consider the transplantation of genetically modified autologous hepatocytes as an alternative to liver transplantation for the treatment of genetic diseases of the liver.Familial hypercholesterolemia (FH) is an autosomal dominant disorder caused by mutations in the gene encoding the receptor for Low Density Lipoproteins (LDLR), which is the cause of high blood cholesterol in these patients. Homozygous patients should purify their serum LDL-apheresis on average twice a month starting at a young age to avoid fatal myocardial infarction occurring in childhood.Human hepatocytes differentiated from patient’s induced pluripotent stem cells (iPSCs) allow assessing the feasibility to transplant genetically modified autologous hepatocytes as treatment of familial hypercholesterolemia.During the liver development, hepatocytes and cholangiocytes, the two types of hepatic epithelial cells, derive from bipotent hepatic progenitors (hepatoblasts). Although cholangiocytes, forming intrahepatic bile ducts, represent a small fraction of the total liver cell population (3%), they actively regulate bile composition by secretion and reabsorption of bile acids, a process that is important in cholestatic liver diseases. In the first part of this study we developed an approach to differentiate pluripotent stem cells (hESC and hiPSC) into functional cholangiocytes. These cells could be used for the modeling of genetic biliary diseases. In the second part, we generated FH patient specific iPSCs (HF-iPSC), differentiated them into hepatocytes and tried to correct the disease phenotype by lentiviral introduction of LDLR cDNA cassette in HF-iPSC.

A nefropatia diabética (ND) decorre da hiperglicemia crônica, de fatores de risco como a hipertensão arterial e a dislipidemia e de uma susceptibilidade genética já evidenciada em inúmeros estudos clínicos. Uma das características histológicas da ND é o acúmulo de proteínas de matriz extracelular no mesângio, para o qual contribuem várias vias bioquímicas. O GLUT-1, codificado pelo gene SLC2A1, é o principal transportador de glucose da célula mesangial e sua expressão está aumentada no glomérulo de animais diabéticos, o que constitui uma alça de feedback positivo pela qual a glicose extracelular aumentada estimula ainda mais sua própria captação, piorando a lesão mesangial. O GLUT-2, codificado pelo gene SLC2A2, é expresso nas células tubulares e nos podócitos e sua expressão também está aumentada na ND. A expressão deste transportador de glicose é regulada pelo fator de transcrição HNF-1. Participa, ainda, da lesão renal induzida pela hiperglicemia o fator de crescimento transformante - (TGF-), que exerce vários efeitos deletérios, tais como diminuir a atividade de metaloproteinases de matriz e promover fibrose renal. Esse fator de crescimento determina a ativação transcricional de genes-alvo, mas necessita de outros ativadores e co-ativadores da transcrição, tais como a proteína SMIF, codificada pelo gene DCP1A. Tendo em vista a participação das proteínas mencionadas acima na patogênese da ND, o presente estudo teve o objetivo de avaliar a associação de polimorfismos de um único nucleotídeo (SNPs) nos genes SLC2A1, SLC2A2, HNF1A, TGFB1 e DCP1A com a doença renal em portadores de diabetes mellitus tipo 1 (DM1). Um total de 449 pacientes (56,4% do sexo feminino, idade média de 36,0±11,0 anos) com mais de 10 anos de doença foram incluídos e classificados de acordo com o estágio de ND: (1) Ausência de ND: excreção urinária de albumina (EUA) normal (< 30 mg/24h ou < 20 g/min) e creatinina plasmática < 1,7 mg/dL sem tratamento anti-hipertensivo; (2) ND incipiente: microalbuminúria (EUA de 30 299 mg/24h ou 20 199 g/min) e creatinina plasmática < 1,7 mg/dL sem tratamento anti-hipertensivo e (3) ND Franca: macroalbuminúria (EUA > 300 mg/24h ou > 200 g/min) ou proteinúria ou tratamento para reposição renal. Também foram avaliadas as associações dos SNPs com o ritmo de filtração glomerular estimado (RFGe). Os SNPs foram genotipados pela metodologia de reação em cadeia da polimerase em tempo real, com o uso de sondas fluorescentes. As associações dos SNPs com a ND foram avaliadas por análise de regressão logística e os odds ratios (OR) e respectivos intervalos de confiança (IC) de 95% foram calculados após ajuste para possíveis confundidores, que foram incluídos como co-variáveis no modelo de regressão. Valores de P < 0.05 (bicaudal) foram considerados estatisticamente significantes. As seguintes associações foram observadas: (1) gene SLC2A1: genótipos CT+TT do SNP rs841848 conferiram risco para a ND incipiente na população global (OR 1,88; CI95% 1,06-3,34; P= 0,03) e nos pacientes do sexo masculino (OR 2,67; CI95% 1,13-6,35; P=0,0247) e para a ND franca (OR 2,70; CI95% 1,18-6,31; e P= 0,0197) apenas nos pacientes do sexo masculino; genótipos GA+AA do SNP rs1385129 conferiram risco para a ND franca na população do sexo masculino (OR 3,09; CI95% 1,34-7,25; P=0,0085); genótipos AT + TT do SNP rs3820589, conferiram proteção contra a ND incipiente na população global (OR 0,36; CI95% 0,16-0,78; P=0,0132) e na população do sexo feminino (OR 0,14; CI95% 0,02-0,52; P=0,0122). (2) gene SLC2A2: genótipos GA+GG do SNP rs5396 conferiram proteção contra ND franca nos pacientes do sexo masculino (OR 0,29; CI95% 0,12-0,69; P=0,0052); os genótipos AG+GG do SNP rs6800180 conferiram proteção contra a ND franca nos pacientes do sexo masculino (OR 0,16; CI95% 0,14-0,90; P=0,0324). (3) gene HNF1A: genótipos AC + CC do SNP rs1169288 conferiram risco para ND franca na população global (OR 2,23; CI95% 1,16-4,38; P=0,0175); genótipos CG+GG do SNP rs1169289 conferiram risco para ND franca na população global (OR 3,43; CI95% 1,61-7,73; P=0,002); (4) Gene TGFB1: genótipos CT + TT do SNP 1800468 conferiram risco para ND incipiente na população total (OR 2,99; CI95% 1,26-7,02; P 0,0116) e o alelo polimórfico T do SNP rs1800469 conferiu risco para um menor RFGe (p=0,0271). (5) gene DCP1A: o alelo polimórfico A do SNP rs11925433 também se associou com um menor RFGe (p=0,0075). Em conclusão, SNPs em genes que codificam as proteínas envolvidas na patogênese da ND GLUT-1, GLUT-2, HNF-1, TGF- e SMIF conferem susceptibilidade para essa complicação crônica nos portadores de DM1 avaliados no presente estudo / Diabetic nephropathy (DN) results from chronic hyperglycemia, risk factors such as hypertension and dyslipidemia as well as from genetic susceptibility, already demonstrated in numerous clinical studies. A histological feature of DN is the accumulation of extracellular matrix proteins in the mesangium after activation of multiple biochemical pathways. GLUT-1, encoded by gene SLC2A1, is the major glucose transporter in mesangial cell and its expression is increased in the glomeruli of diabetic animals, comprising a positive feedback loop whereby high extracellular glucose stimulates its own uptake and worsening mesangial injury. GLUT-2, encoded by SLC2A2 gene, is expressed in podocytes and tubular cells and its expression is also increased in DN. The expression of this glucose transporter is regulated by the transcription factor HNF-1. Transforming growth factor - (TGF-) also participates in renal injury induced by hyperglycemia, exerting several deleterious effects, such as to decrease the activity of matrix metalloproteinases and to promote renal fibrosis. This growth factor determines the transcriptional activation of target genes, but needs other activators and co-activators, such as the protein named SMIF, encoded by the gene DCP1A. Given the involvement of the aforementioned proteins in the pathogenesis of DN, the present study aimed to evaluate the association of single nucleotide polymorphisms (SNPs) in the genes SLC2A1, SLC2A2, HNF1A, TGFB1 e DCP1A with renal disease in patients with type 1 diabetes mellitus (T1DM). A total of 449 patients (56.4% female, mean age 36.0±11.0 years) with disease duration > 10 years were included and grouped according to DN stages: (1) absence of DN: normal urinary albumin excretion (UAE) (< 30 mg/24h or < 20 g/min) and plasmatic creatinine < 1.7 mg/dL without antihypertensive treatment; (2) incipient DN: microalbuminuria (UAE 30 299 mg/24h or 20 199 g/min) and plasmatic creatinine < 1.7 mg/dL without antihypertensive treatment and (3) overt DN: macroalbuminúria (UAE > 300 mg/24h or > 200 g/min) or proteinuria or renal replacement therapy. Associations of SNPs with estimated glomerular filtration rate (eGFR) were also evaluated. All SNPs were genotyped by real time polymerase chain reaction using fluorescent-labelled probes. Associations of the SNPs with DN were assessed by logistic regression analyses and odds ratios (OR) were calculated after adjustments for possible confounders included as covariables in the regressive model. P values <0.05 (two-tails) were considered significant. The following associations were observed: (1) SLC2A1: genotypes CT+TT from rs841848 conferred risk to incipient DN in the overall population (OR 1.88; 95%IC 1.06-3.34; P= 0.03) and in the male patients (OR 2.67; CI95% 1.13-6.35; P=0.0247) and to overt DN (OR 2.70; CI95% 1.18-6.31; e P= 0.0197) only in the male patients; genotypes GA+AA from rs1385129 conferred risk to overt DN in the male population (OR 3.09; CI95% 1.34-7.25; P=0.0085); genotypes AT + TT from rs3820589 conferred protection against incipient DN in the overall population (OR 0.36; CI95% 0.16-0.78; P=0.0132) and in the female population (OR 0.14; CI95% 0.02-0.52; P=0.0122). (2) SLC2A2: genotypes GA+GG from rs5396 conferred protection against overt DN in the male patients (OR 0.29; CI95% 0.12-0.69; P=0.0052); genotypes AG+GG from rs6800180 conferred protection against overt DN in the male patients (OR 0.16; CI95% 0.14-0.90; P=0.0324). (3) HNF1A: genotypes AC + CC from rs1169288 conferred risk to overt DN in the overall population (OR 2.23; CI95% 1.16-4.38; P=0.0175); genotypes CG+GG from rs1169289 conferred risk to overt DN in the overall population (OR 3.43; CI95% 1.61-7.73; P=0.002); (4) TGFB1: genotypes CT + TT from 1800468 conferred risk to incipient DN in the overall population (OR 2.99; CI95% 1.26-7.02; P=0.0116) and the polymorphic allele T from SNP rs1800469 conferred risk to a lower eGFR (p=0.0271). (5) DCP1A: the polymorphic allele A from SNP rs11925433 was also associated with a lower eGFR (p=0.0075). In conclusion, SNPs in the genes encoding proteins GLUT-1, GLUT-2, HNF-1, TGF- e SMIF, all involved in the pathogenesis of DN, conferred susceptibility to this chronic complication in the T1DM patients evaluated in the present study