PAX4 gene delivery improves ß-cell function in human islets of Type II diabetes.

Aim: Type II diabetes (T2D) stems from insulin resistance, with ß-cell dysfunction as a hallmark in its progression. Studies reveal that ß cells undergo apoptosis or dedifferentiation during T2D development. The transcription factor PAX4 is vital for ß differentiation and survival, thus may be a potential enhancer of ß-cell function in T2D islets. Materials & methods: Human PAX4 cDNA was delivered into T2D human islets with an adenoviral vector, and its effects on ß cells were examined. Results: PAX4 gene delivery significantly improved ß-cell survival, and increased ß-cell composition in the T2D human islets. Basal insulin and glucose-stimulated insulin secretion in PAX4-expressing islets were substantially higher than untreated or control-treated T2D human islets. Conclusion: Introduced PAX4 expression in T2D human islets improves ß-cell function, thus could provide therapeutic benefits for T2D treatment.

Type II diabetes (T2D) results from insulin resistance, with ß-cell dysfunction playing a pivotal role in its progression. Deficits in ß-cell mass and function have been attributed primarily to ß-cell death through apoptosis; however, recent studies suggest ß-cell failure can also arise from ß-cell dedifferentiation ­ that is, ß cells undergo a loss of mature identity, adopting either progenitor-like or glucagon-producing α cell states during T2D development. Therefore, a strategy preventing ß-cell dedifferentiation while promoting its survival is beneficial for T2D treatment. In this study, we explored whether PAX4, a critical transcription factor for ß differentiation and survival, could alleviate ß-cell dysfunction in human islets derived from T2D patients. To accomplish that, human PAX4 cDNA was delivered into human islets isolated from T2D donors by an adenoviral vector-based vector, Ad5.Pax4 and its effects on ß-cell function were evaluated. The results showed PAX4 expression significantly improved ß-cell survival and increased ß-cell composition in the T2D islets. Notably, PAX4-treated T2D islets exhibited significantly higher basal insulin secretion and glucose-stimulated insulin secretion than control-treated islets. The data demonstrate that PAX4 gene delivery into T2D human islets enhances ß-cell mass and function, and thus may offer therapeutic benefits in the treatment of T2D.

Rosa canina extract relieves methylation alterations of pancreatic genes in STZ-induced diabetic rats : Gene methylation in diabetic rats treated with an extract.

BACKGROUND: Diabetes is a chronic metabolic disease that affects many parts of the body. Considering diabetes as a beta cells' defect and loss, the focus is on finding mechanisms and compounds involved in stimulating the function and regeneration of pancreatic ß-cells. DNA methylation as an epigenetic mechanism plays a pivotal role in the ß-cells' function and development. Considering the regenerative and anti-diabetic effects of Rosa canina extract, this study aimed to assess the methylation levels of Pdx-1, Pax-4, and Ins-1 genes in diabetic rats treated with Rosa Canina extract. METHODS AND RESULTS: Streptozotocin-induced diabetic rats were used to evaluate the frequency of Pdx-1, Pax-4, and Ins-1 gene methylation. Treatment groups were exposed to Rosa canina as spray-dried and decoction extracts. Following blood glucose measurement, pancreatic DNA was extracted and bisulfited. Genes' methylation was measured using MSP-PCR and qRT-PCR techniques. Oral administration of Rosa canina extracts significantly reduced blood sugar levels in diabetic rats compared to the control group. The methylation levels of the Pdx-1, Pax-4, and Ins-1 genes promoter in streptozotocin-induced diabetic rats increased compared to the control rats while, the treatment of diabetic rats with Rosa canina extracts, spray-dried samples especially, led to a decreased methylation in these genes. CONCLUSION: The results of this study showed that Rosa canina extract as a spray-dried sample could be effective in treating diabetes by regulating the methylation of genes including Pdx-1, Pax-4, and Ins-1 involved in the activity and regeneration of pancreatic islet cells.

The effects of transcription factor 7-like 2 rs7903146 and paired box 4 rs2233580 variants associated with type 2 diabetes on the therapeutic efficacy of hypoglycemic agents.

Aim: This study aims to investigate the effects of the TCF7L2 rs7903146 and PAX4 rs2233580 (R192H) variants associated with T2D on the therapeutic efficacies of various HAs in patients with T2D after follow-up for 3 years. Methods: A total of 526 patients who were followed up at the Diabetic Clinic of Siriraj Hospital during 2016-2019 were enrolled. The variants TCF7L2 rs7903146 and PAX4 rs2233580 (R192H) were genotyped using the RNase H2 enzyme-based amplification (rhAmp) technique and the associations between genotypes and glycemic control after treatments with different combinations HA were evaluated using Generalized Estimating Equations (GEE) analysis. Results: Patients who carried TCF7L2 rs7903146C/T + T/T genotypes when they were treated with biguanide alone had significantly lower fasting plasma glucose (FPG) than those of the patients who carried the C/C genotype (p = 0.01). Patients who carried the PAX4 rs2233580 G/G genotype when they were treated with sulfonylurea alone had significantly lower FPG than those of the patients who carried G/A + A/A genotypes (p = 0.04). Conclusion: Genotypes of TCF7L2 rs7903146 and PAX4 rs2233580 (R192H) variants associated with T2D influence the therapeutic responses to biguanide and sulfonylurea. Different genotypes of these two variants might distinctively affect the therapeutic effects of HAs. This finding provides evidence of pharmacogenetics in the treatment of diabetes.

A Case of Maturity-Onset Diabetes of the Young With Complex Mutations.

Maturity-onset diabetes of the young (MODY) encompasses a group of rare monogenic forms of diabetes, with 14 subtypes described in the literature, each with a distinct underlying genetic mutation. We present a case with mutations in 2 different genes that are known to be responsible for MODY. A 33-year-old male individual presented to the endocrinology clinic for evaluation. He was diagnosed with type 2 diabetes mellitus at 13 years of age and was initially treated with insulin, which was subsequently switched to repaglinide and metformin. The patient reported a history of hypoglycemia at birth and in his daughter. His biological father was diagnosed with diabetes mellitus at 16 years of age. Genetic testing for monogenic diabetes revealed a pathogenic variant in hepatocyte nuclear factor 4 alpha and a variant of unknown significance in Paired Box Gene 4. The treatment was switched to glipizide 2.5 mg orally, which resulted in adequate glycemic control. Genetic testing was recommended for his daughter. MODY can be missed because of its broad clinical presentation. Heightened vigilance and a low threshold for genetic testing for MODY are required in patients with a high likelihood of having MODY, as the treatment can be tailored to individual patient needs.

Novel PAX4 variant in a child and family with diabetes mellitus - case report and review of the literature.

OBJECTIVES: PAX4 (Paired box 4), a transcription factor crucial in pancreatic beta cell development and function, is a rare cause of maturity-onset diabetes of the young (MODY). What is new? A novel PAX4 variant is verified by family segregation study to be likely pathogenic. A child below 10 years of age diagnosed to have PAX4-MODY, differing from previously reported paediatric cases diagnosed in adolescence. CASE PRESENTATION: A child with diabetes diagnosed at age 8 years, harbored a PAX4 variant, c.890G>A (p.Gly297Asp), initially classified as variant of uncertain significance. Eleven family members (7 adults and 4 children) with and without diabetes across 3 generations were genotyped. The variant co-segregated with diabetes or prediabetes across 3 generations of the family. The variant is reclassified as likely pathogenic according to standard guidelines. CONCLUSIONS: Genetic testing is essential to confirm PAX4-MODY as the presentation is variable even within the same family. PAX4 mutation needs to be considered in MODY genetic testing in Asian patients.

Production of Bioactive Human PAX4 Protein from E. coli.

Paired box 4 (PAX4) is a pivotal transcription factor involved in pancreatogenesis during embryogenesis, and in adults, it is key for ß-cell proliferation and survival. Additionally, PAX4 also functions as a tumor suppressor protein in human melanomas. The present study demonstrates the production of bioactive recombinant human PAX4 transcription factor. At first, the inserts (PAX4 protein-coding sequence having tags at either ends) were cloned in an expression vector to give rise to pET28a(+)-HTN-PAX4 and pET28a(+)-PAX4-NTH genetic constructs, and these were then transformed into Escherichia coli (E. coli) for their expression. The HTN-PAX4 and PAX4-NTH fusion proteins produced were purified with a yield of ~ 3.15 mg and ~ 0.83 mg, respectively, from 1.2 L E. coli culture. Further, the secondary structure retention of the PAX4 fusion proteins and their potential to internalize the mammalian cell and its nucleus was demonstrated. The bioactivity of these fusion proteins was investigated using various assays (cell migration, cell proliferation and cell cycle assays), demonstrating it to function as a tumor suppressor protein. Thus, this macromolecule can prospectively help understand the function of human PAX4 in cellular processes, disease-specific investigations and direct cellular reprogramming.

Maturity-onset diabetes of the young type 9 or latent autoimmune diabetes in adults: A case report and review of literature.

BACKGROUND: Maturity-onset diabetes of the young (MODY) is a monogenic genetic disease often clinically misdiagnosed as type 1 or type 2 diabetes. MODY type 9 (MODY9) is a rare subtype caused by mutations in the PAX4 gene. Currently, there are limited reports on PAX4-MODY, and its clinical characteristics and treatments are still unclear. In this report, we described a Chinese patient with high autoimmune antibodies, hyperglycemia and a site mutation in the PAX4 gene. CASE SUMMARY: A 42-year-old obese woman suffered diabetes ketoacidosis after consuming substantial amounts of beverages. She had never had diabetes before, and no one in her family had it. However, her autoantibody tested positive, and she managed her blood glucose within the normal range for 6 mo through lifestyle inter-ventions. Later, her blood glucose gradually increased. Next-generation sequencing and Sanger sequencing were performed on her family. The results revealed that she and her mother had a heterozygous mutation in the PAX4 gene (c.314G>A, p.R105H), but her daughter did not. The patient is currently taking liraglutide (1.8 mg/d), and her blood glucose levels are under control. Previous cases were retrieved from PubMed to investigate the relationship between PAX4 gene mutations and diabetes. CONCLUSION: We reported the first case of a PAX4 gene heterozygous mutation site (c.314G>A, p.R105H), which does not appear pathogenic to MODY9 but may facilitate the progression of latent autoimmune diabetes in adults.

Pax4 in Health and Diabetes.

Paired box 4 (Pax4) is a key transcription factor involved in the embryonic development of the pancreatic islets of Langerhans. Consisting of a conserved paired box domain and a homeodomain, this transcription factor plays an essential role in early endocrine progenitor cells, where it is necessary for cell-fate commitment towards the insulin-secreting ß cell lineage. Knockout of Pax4 in animal models leads to the absence of ß cells, which is accompanied by a significant increase in glucagon-producing α cells, and typically results in lethality within days after birth. Mutations in Pax4 that cause an impaired Pax4 function are associated with diabetes pathogenesis in humans. In adulthood, Pax4 expression is limited to a distinct subset of ß cells that possess the ability to proliferate in response to heightened metabolic needs. Upregulation of Pax4 expression is known to promote ß cell survival and proliferation. Additionally, ectopic expression of Pax4 in pancreatic islet α cells or δ cells has been found to generate functional ß-like cells that can improve blood glucose regulation in experimental diabetes models. Therefore, Pax4 represents a promising therapeutic target for the protection and regeneration of ß cells in the treatment of diabetes. The purpose of this review is to provide a thorough and up-to-date overview of the role of Pax4 in pancreatic ß cells and its potential as a therapeutic target for diabetes.

Pax4-Ghrelin mediates the conversion of pancreatic ε-cells to ß-cells after extreme ß-cell loss in zebrafish.

Pancreatic ε-cells producing ghrelin are one type of endocrine cell found in islets, which have been shown to influence other intra-islet cells, especially in regulating the function of ß cells. However, the role of such cells during ß-cell regeneration is currently unknown. Here, using a zebrafish nitroreductase (NTR)-mediated ß-cell ablation model, we reveal that ghrelin-positive ε-cells in the pancreas act as contributors to neogenic ß-cells after extreme ß-cell loss. Further studies show that the overexpression of ghrelin or the expansion of ε-cells potentiates ß-cell regeneration. Lineage tracing confirms that a proportion of embryonic ε-cells can transdifferentiate to ß-cells, and that the deletion of Pax4 enhances this transdifferentiation of ε-cells to ß-cells. Mechanistically, Pax4 binds to the ghrelin regulatory region and represses its transcription. Thus, deletion of Pax4 derepresses ghrelin expression and causes producing more ghrelin-positive cells, enhancing the transdifferentiation of ε-cells to ß-cells and consequently potentiating ß-cell regeneration. Our findings reveal a previously unreported role for ε-cells during zebrafish ß-cell regeneration, indicating that Pax4 regulates ghrelin transcription and mediates the conversion of embryonic ε-cells to ß-cells after extreme ß-cell loss.

A 2-bp deletion in intron 1 of TMEM182 is associated with TMEM182 mRNA expression and chicken body weight.

1. Searching for molecular markers related to growth and carcase traits plays a critical role in improvement of the production performance of broilers. Previous studies found that transmembrane protein 182 (TMEM182) inhibits skeletal muscle development, growth, and regeneration, implying that the TMEM182 gene plays an important role during the development process of skeletal muscle.2. A novel 2-bp indel in intron 1 of TMEM182 was detected in a yellow chicken population derived from the cross of White Recessive Rock chickens with Xinghua chickens, and three genotypes II (inserted homozygote), ID (inserted and deleted heterozygote) and DD (deleted homozygote) were observed. Association analyses indicated that the indel was significantly associated with the body weight, muscle fibre area, breast muscle weight and wing weight in the F2 population.3. The expression of TMEM182 in leg muscle of chickens with II genotype was higher than that with DD genotype, with the 2-bp indel located in one of the putative PAX4 binding sites. Further research through luciferase assays revealed that the PAX4 could bind to the putative binding site and increase the TMEM182 transcription, with the 2-bp deletion disrupting the binding of PAX4.4. The present study provides evidence for the association of the novel 2-bp indel in intron 1 of TMEM182 with the growth and carcase traits of chickens. This 2-bp indel could be used as a genetic marker in broiler breeding.

Conversion of Gastrointestinal Somatostatin-Expressing D Cells Into Insulin-Producing Beta-Like Cells Upon Pax4 Misexpression.

Type 1 diabetes results from the autoimmune-mediated loss of insulin-producing beta-cells. Accordingly, important research efforts aim at regenerating these lost beta-cells by converting pre-existing endogenous cells. Following up on previous results demonstrating the conversion of pancreatic somatostatin delta-cells into beta-like cells upon Pax4 misexpression and acknowledging that somatostatin-expressing cells are highly represented in the gastrointestinal tract, one could wonder whether this Pax4-mediated conversion could also occur in the GI tract. We made use of transgenic mice misexpressing Pax4 in somatostatin cells (SSTCrePOE) to evaluate a putative Pax4-mediated D-to-beta-like cell conversion. Additionally, we implemented an ex vivo approach based on mice-derived gut organoids to assess the functionality of these neo-generated beta-like cells. Our results outlined the presence of insulin+ cells expressing several beta-cell markers in gastrointestinal tissues of SSTCrePOE animals. Further, using lineage tracing, we established that these cells arose from D cells. Lastly, functional tests on mice-derived gut organoids established the ability of neo-generated beta-like cells to release insulin upon stimulation. From this study, we conclude that the misexpression of Pax4 in D cells appears sufficient to convert these into functional beta-like cells, thus opening new research avenues in the context of diabetes research.

Ethnic-Specific Type 2 Diabetes Risk Factor PAX4 R192H Is Associated with Attention-Specific Cognitive Impairment in Chinese with Type 2 Diabetes.

BACKGROUND: Type 2 diabetes mellitus (T2DM) has been shown to increase the risks of cognitive decline and dementia. Paired box gene 4 (PAX4), a transcription factor for beta cell development and function, has recently been implicated in pathways intersecting Alzheimer's disease and T2DM. OBJECTIVE: In this report, we evaluated the association of the ethnic-specific PAX4 R192H variant, a T2DM risk factor for East Asians which contributes to earlier diabetes onset, and cognitive function of Chinese T2DM patients. METHODS: 590 Chinese patients aged 45-86 from the SMART2D study were genotyped for PAX4 R192H variation using Illumina OmniExpress-24 Array. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) which had been validated in the Singapore population was administered to assess five cognitive domains: immediate memory, visuospatial/constructional, language, attention, and delayed memory. Multiple linear regression was used to assess the association of the R192H risk allele and cognitive domains. RESULTS: Patients with two PAX4 R192H risk alleles showed significantly lower attention index score (ß= -8.46, 95% CI [-13.71, -3.21], p = 0.002) than patients with wild-type alleles after adjusting for age, gender, diabetes onset age, HbA1c, body-mass index, renal function, lipid profiles, systolic blood pressure, metformin usage, smoking history, education level, Geriatric Depression Scale score, and presence of APOEɛ4 allele. CONCLUSION: Ethnic-specific R192H variation in PAX4 is associated with attention-specific cognitive impairment in Chinese with T2DM. Pending further validation studies, determining PAX4 R192H genotype may be helpful for early risk assessment of early-onset T2DM and cognitive impairment to improve diabetes care.

Transcription factor PAX4 facilitates gastric cancer progression through interacting with miR-27b-3p/Grb2 axis.

Gastric cancer (GC) is one of the most common aggressive cancers. The discovery of an effective biomarker is necessary for GC diagnosis. In this study, we confirmed that Paired box gene 4 (PAX4) is up-regulated in GC tissues and cells via quantitative real time polymerase chain reaction (qRT-PCR), western blot and immunohistochemical staining. It was also identified that PAX4 contributed to GC cell proliferation, migration and invasion through Cell Counting Kit-8, BrdU, flow cytometry assay, colony formation assay, transwell assays, and wound healing assay. miR-27b-3p was confirmed with the binding site with PAX4 using ChIP assay and served as a tumor suppressor that inhibiting GC cell growth and metastasis, and reversed the effect of PAX4. Bioinformatics prediction and dual luciferase assay results demonstrated that miR-27b-3p targeted Grb2, which could alter the function of miR-27b-3p. Furthermore, the transcriptional control of PAX4-regulated miR-27b-3p activated the Ras-ERK pathway. Taken together, the PAX4/miR-27b-3p/Grb2 loop is known to be involved in GC cell promotion, and can be seen as a promising target for GC therapy.

Harnessing the Endogenous Plasticity of Pancreatic Islets: A Feasible Regenerative Medicine Therapy for Diabetes?

Diabetes is a chronic metabolic disease caused by an absolute or relative deficiency in functional pancreatic ß-cells that leads to defective control of blood glucose. Current treatments for diabetes, despite their great beneficial effects on clinical symptoms, are not curative treatments, leading to a chronic dependence on insulin throughout life that does not prevent the secondary complications associated with diabetes. The overwhelming increase in DM incidence has led to a search for novel antidiabetic therapies aiming at the regeneration of the lost functional ß-cells to allow the re-establishment of the endogenous glucose homeostasis. Here we review several aspects that must be considered for the development of novel and successful regenerative therapies for diabetes: first, the need to maintain the heterogeneity of islet ß-cells with several subpopulations of ß-cells characterized by different transcriptomic profiles correlating with differences in functionality and in resistance/behavior under stress conditions; second, the existence of an intrinsic islet plasticity that allows stimulus-mediated transcriptome alterations that trigger the transdifferentiation of islet non-ß-cells into ß-cells; and finally, the possibility of using agents that promote a fully functional/mature ß-cell phenotype to reduce and reverse the process of dedifferentiation of ß-cells during diabetes.

Missense Variants in PAX4 Are Associated with Early-Onset Diabetes in Chinese.

INTRODUCTION: East Asians are more susceptible to early-onset diabetes than Europeans and exhibit reduced insulin secretion at earlier stages. PAX4 plays a critical role in the development of ß-cells. The dysfunction-missense variants PAX4 R192H and PAX4 R192S are common in East Asians but rare in Europeans. Therefore, we aim to investigate the diabetes-associated genes, including PAX4 R192H/S, in East Asians with early-onset diabetes. METHODS: Exome variants of 80 Chinese early-onset diabetes patients (onset age < 35 years) after the exclusion of type 1 diabetes (T1D) were detected by a customized gene panel covering 32 known diabetes-associated genes. Then, 229 subjects with early-onset diabetes (T1D excluded) and 1679 controls from the Chinese population were genotyped to validate the association of PAX4 R192H/S with early-onset diabetes and related phenotypes. RESULTS: The gene panel detected 11 monogenic diabetes patients with five novel mutations among the 80 early-onset diabetes patients. Asian-specifically enriched PAX4 R192H and R192S were associated with early-onset diabetes (R192H: OR 1.88, 95% CI 1.37-2.60, P = 8.41 × 10-5; R192S: OR 1.71, 95% CI 1.17-2.51, P = 0.005). In early-onset diabetes patients, PAX4 R192H carriers had higher haemoglobin A1c (HbA1c) levels (P = 0.030) and lower 2 h C-peptide levels in the oral glucose tolerance test (OGTT) (P = 0.040); R192S carriers had lower fasting C-peptide (FCP) (P = 0.011) and 2 h C-peptide levels (P = 0.033) in OGTT than non-variant carriers. CONCLUSIONS: The ethnic-specific enrichment of PAX4 R192H/S predisposing East Asians to early-onset diabetes with decreased C-peptide levels may be one explanation of the discrepancy of diabetes between East Asians and Europeans. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov (NCT01938365).

[Alternative Variants of Pax4 Human Transcription Factor: Comparative Transcriptional Activity].

MODY is a group of genetically and clinically heterogeneous forms of diabetes characterized by auto-somal dominant inheritance and is subdivided in 13 subtypes dependent on the gene involved. The subtype MODY9 is a very rare form caused by mutations in the gene encoding the PAX4 transcription factor which is engaged in differentiation of pancreatic beta-cells. PAX4 contains two DNA-binding domains-Paired and Homeo. Expression of the human PAX4 gene is tissue-specific. The alternatively spliced mRNA variants encode for protein isoforms which differ within their N- and C-terminal regions. In this study, the transcriptional activities of the human PAX4 variants, both known and new ones, were determined. The full-length PAX4 containing intact DNA-binding domains was found to have maximal activity in transient expression system of the firefly luciferase reporter gene under control of the insulin promoter in HEK293 cells. The transcriptional activity is significantly reduced in the variants lacking eight N-terminal amino acid residues and/or variants whose Homeo domain is truncated from the C-terminus. Similar data were obtained with the glucagon promoter reporter system. The aberrant PAX4 variants were shown to retain stability and nuclear localization.

Pax4 Gene Delivery Improves Islet Transplantation Efficacy by Promoting ß Cell Survival and α-to-ß Cell Transdifferentiation.

The transcription factor Pax4 plays an essential role in the development of insulin-producing ß cells in pancreatic islets. Ectopic Pax4 expression not only promotes ß cell survival but also induces α-to-ß cell transdifferentiation. This dual functionality of Pax4 makes it an appealing therapeutic target for the treatment of insulin-deficient type 1 diabetes (T1D). In this study, we demonstrated that Pax4 gene delivery by an adenoviral vector, Ad5.Pax4, improved ß cell function of mouse and human islets by promoting islet cell survival and α-to-ß cell transdifferentiation, as assessed by multiple viability assays and lineage-tracing analysis. We then explored the therapeutic benefits of Pax4 gene delivery in the context of islet transplantation using T1D mouse models. Both mouse-to-mouse and human-to-mouse islet transplantation, via either kidney capsule or portal vein, were examined. In all settings, Ad5.Pax4-treated donor islets (mouse or human) showed substantially better therapeutic outcomes. These results suggest that Pax4 gene delivery into donor islets may be considered as an adjunct therapy for islet transplantation, which can either improve the therapeutic outcome of islet transplantation using the same amount of donor islets or allow the use of fewer donor islets to achieve normoglycemia.

Identification of the First PAX4-MODY Family Reported in Brazil.

PURPOSE: The aim of this study was to sequence the coding region of the PAX4 gene in a Brazilian cohort with clinical manifestations of monogenic diabetes. PATIENTS AND METHODS: This study included 31 patients with autosomal dominant history of diabetes, age at diagnosis ≤40 years, BMI <30 kg/m2, and no mutations in GCK or HNF1A, HNF4A, and HNF1B. Screening of the PAX4 coding region was performed by Sanger sequencing. In silico algorithms were used to assess the potential impact of amino acid substitutions on protein structure and function. Additionally, PAX4-MODY family members and 158 control subjects without diabetes were analyzed for the identified mutation. RESULTS: The molecular analysis of PAX4 has detected one missense mutation, p.Arg164Gln (c.491G>A), segregating with diabetes in a large Brazilian family. The mutation was absent among the control group. The index case is a woman diagnosed at 32 years of age with polyneuropathy and treated with insulin. She did not present diabetic renal disease or retinopathy. Family members with the PAX4 p.Arg164Gln mutation have a heterogeneous clinical manifestation and treatment response, with age at diagnosis ranging from 24 years to 50 years. CONCLUSION: To the best of our knowledge, this is the first study to report a PAX4-MODY family in Brazil. The age of PAX4-MODY diagnosis in the Brazilian family seems to be higher than the classical criteria for MODY. Our results reinforce the importance of screening large monogenic diabetes families for the understanding of the clinical manifestations of rare forms of diabetes for the specific and personalized treatment.

Molecular Modelling of Islet ß-Cell Adaptation to Inflammation in Pregnancy and Gestational Diabetes Mellitus.

Gestational diabetes mellitus (GDM), a metabolic disease that develops with the increase in insulin resistance during late pregnancy, is currently one of the most common complications affecting pregnancy. The polygenic nature of GDM, together with the interplay between different genetic variants with nutritional and environmental factors has hindered the full understanding of the etiology of this disease. However, an important genetic overlap has been found with type 2 diabetes mellitus (T2DM) and, as in the case of T2DM, most of the identified loci are associated with ß-cell function. Early detection of GDM and adequate interventions to control the maternal glycemia are necessary to avoid the adverse outcomes for both the mother and the offspring. The in utero exposure to the diabetic milieu predispose these children for future diseases, among them T2DM, originating a vicious circle implicated in the increased prevalence of both GDM and T2DM. The involvement of inflammatory processes in the development of GDM highlights the importance of pancreatic ß-cell factors able to favor the adaptation processes required during gestation, concomitantly with the protection of the islets from an inflammatory milieu. In this regard, two members of the Pax family of transcription factors, PAX4 and PAX8, together with the chromatin remodeler factor HMG20A, have gained great relevance due to their involvement in ß-cell mass adaptation together with their anti-inflammatory properties. Mutations in these factors have been associated with GDM, highlighting these as novel candidates for genetic screening analysis in the identification of women at risk of developing GDM.

Pax4 synergistically acts with Pdx1, Ngn3 and MafA to induce HuMSCs to differentiate into functional pancreatic ß-cells.

It has been indicated that the combination of pancreatic and duodenal homeobox 1 (Pdx1), MAF bZIP transcription factor A (MafA) and neurogenin 3 (Ngn3) was able to reprogram various cell types towards pancreatic ß-like cells (pßLCs). Paired box 4 (Pax4), a transcription factor, has a key role in regulating the maturation of pancreatic ß-cells (pßCs). In the present study, it was investigated whether Pax4 is able to synergistically act with Pdx1, Ngn3 and MafA to induce human umbilical cord mesenchymal stem cells (HuMSCs) to differentiate into functional pßCs in vitro. HuMSCs were isolated, cultured and separately transfected with adenovirus (Ad) expressing enhanced green fluorescence protein, Pax4 (Ad-Pax4), Pdx1+MafA+Ngn3 (Ad-3F) or Ad-Pxa4 + Ad-3F. The expression of C-peptide, insulin and glucagon was detected by immunofluorescence. The transcription of a panel of genes was determined by reverse transcription-quantitative PCR, including glucagon (GCG), insulin (INS), NK6 homeobox 1 (NKX6-1), solute carrier family 2 member 2 (SLC2A2), glucokinase (GCK), proprotein convertase subtilisin/kexin type 1 (PCSK1), neuronal differentiation 1 (NEUROD1), ISL LIM homeobox 1 (ISL 1), Pax6 and PCSK type 2 (PCSK2). Insulin secretion stimulated by glucose was determined using ELISA. The results suggested that, compared with Ad-3F alone, cells co-transfected with Ad-Pax4 and Ad-3F expressed higher levels of INS and C-peptide, as well as genes expressed in pancreatic ß precursor cells, and secreted more insulin in response to high glucose. Furthermore, the expression of GCG in cells transfected with Ad-3F was depressed by Ad-Pax4. The present study demonstrated that Pax4 was able to synergistically act with the transcription factors Pdx1, Ngn3 and MafA to convert HuMSCs to functional pßLCs. HuMSCs may be potential seed cells for generating functional pßLCs in the therapy of diabetes.