Insulin acts through FOXO3a to activate transcription of plasminogen activator inhibitor type 1

Ketosis Suppression and Ageing (KetoSAge): The Effects of Suppressing Ketosis in Long Term Keto-Adapted Non-Athletic Females

Most studies on ketosis have focused on short-term effects, male athletes, or weight loss. Hereby, we studied the effects of short-term ketosis suppression in healthy women on long-standing ketosis. Ten lean (BMI 20.5 ± 1.4), metabolically healthy, pre-menopausal women (age 32.3 ± 8.9) maintaining nutritional ketosis (NK) for > 1 year (3.9 years ± 2.3) underwent three 21-day phases: nutritional ketosis (NK; P1), suppressed ketosis (SuK; P2), and returned to NK (P3). Adherence to each phase was confirmed with daily capillary D-beta-hydroxybutyrate (BHB) tests (P1 = 1.9 ± 0.7; P2 = 0.1 ± 0.1; and P3 = 1.9 ± 0.6 pmol/L). Ageing biomarkers and anthropometrics were evaluated at the end of each phase. Ketosis suppression significantly increased: insulin, 1.78-fold from 33.60 (± 8.63) to 59.80 (± 14.69) pmol/L (p = 0.0002); IGF1, 1.83-fold from 149.30 (± 32.96) to 273.40 (± 85.66) µg/L (p = 0.0045); glucose, 1.17-fold from 78.6 (± 9.5) to 92.2 (± 10.6) mg/dL (p = 0.0088); respiratory quotient (RQ), 1.09-fold 0.66 (± 0.05) to 0.72 (± 0.06; p = 0.0427); and PAI-1, 13.34 (± 6.85) to 16.69 (± 6.26) ng/mL (p = 0.0428). VEGF, EGF, and monocyte chemotactic protein also significantly increased, indicating a pro-inflammatory shift. Sustained ketosis showed no adverse health effects, and may mitigate hyperinsulinemia without impairing metabolic flexibility in metabolically healthy women.

Mechanism of histone deacetylase HDAC2 in FOXO3-mediated trophoblast pyroptosis in preeclampsia

Histone deacetylase 2 (HDAC2) has been demonstrated to regulate trophoblast behaviors. However, its role in trophoblast pyroptosis remains unknown. This study sought to analyze the molecular mechanism of HDAC2 in trophoblast pyroptosis in PE. Expression levels of HDAC2, forkhead box O3 (FOXO3), and protein kinase R-like endoplasmic reticulum kinase (PERK) in placenta tissues and HTR8/SVneo cells and H3K27ac levels in cells were determined. Levels of IL-1β and IL-18 in placenta tissues were determined, and their correlation with HDAC2 was analyzed. Cell proliferation, migration, and invasion were evaluated, and levels of pyroptosis-associated proteins and cytokines were determined. The enrichments of H3K27 acetylation (H3K27ac) and FOXO3 in the FOXO3/PERK promoter region were determined. HDAC2 was downregulated, and FOXO3, PERK, IL-1β, and IL-18 levels were elevated in PE placenta tissues. In HTR8/SVneo cells, HDAC2 downregulation suppressed cell proliferation, migration, and invasion and increased pyroptosis. HDAC2 erased H3K27ac in the FOXO3 promoter region and repressed FOXO3, and FOXO3 bound to the PERK promoter and increased PERK transcription. Functional rescue experiments revealed that silencing FOXO3 or PERK counteracted HDAC2 downregulation-induced cell pyroptosis. Overall, HDAC2 downregulation enhanced H3K27ac to activate FOXO3 and PERK, leading to the occurrence of trophoblast pyroptosis in PE.

Exploring the pathogenesis of type 2 diabetes mellitus intestinal damp-heat syndrome and the therapeutic effect of Gegen Qinlian Decoction from the perspective of exosomal miRNA

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes is a common, complex, chronic metabolic disease. A randomized, double-blind, placebo-parallel controlled clinical study has shown that Gegen Qinlian Decoction (GQD) can reduce glycosylated hemoglobin in type 2 diabetes mellitus (T2DM) intestinal damp-heat syndrome patients in a dose-dependent manner.

AIM

To explore the pathogenesis of T2DM intestinal damp-heat syndrome and the therapeutic effect of GQD from the perspective of exosomal microRNA (miRNA).

METHODS

Eligible patients were selected and treated with GQD for 3 months to evaluate their clinical efficacy. Effective cases were matched with healthy volunteers, and saliva samples were collected. Exosomal miRNA was extracted from saliva and analyzed by chip sequencing. Subsequently, the function of the differential gene and the signal transduction pathway were analyzed using bioinformatics technology. Finally, three target miRNAs were randomly selected from the T2DM group/healthy group, and two target miRNAs in the T2DM before treatment/after treatment group were randomly selected for qPCR verification. Finally, we conducted a correlation analysis of the miRNAs and clinical indicators. The registration number for this research is ChiCTR-IOR-15006626.

RESULTS

(1) The expression of exosomal miRNA chips showed that there were 14 differentially expressed miRNAs in the T2DM group/healthy group, and 26 differentially expressed miRNAs in the T2DM before treatment/after treatment group. (2) Enrichment results showed that in the T2DM group/healthy group, it was primarily related to cell development, body metabolism, TGF-β, and ErbB signaling pathways. In the T2DM before treatment/after treatment group, it was mainly related to cellular metabolic regulation processes, and insulin, Wnt, and AMPK signaling pathways. (3) The qPCR verification showed that the expressions of hsa-miR-9-5p, hsa-miR-150-5p, and hsa-miR-216b-5p in the T2DM group was higher (P<0.05). Following GQD treatment, hsa-miR-342-3p and hsa-miR-221-3p were significantly downregulated (P<0.05). (4) hsa-miR-9-5p was positively correlated with BMI (P<0.05), and hsa-miR-150-5p was positively correlated with total cholesterol and triglycerides (P<0.05). The GQD efficacy-related gene hsa-miR-342-3p was positively correlated with the patient's initial blood glucose level (P<0.05), and hsa-miR-221-3p was positively correlated with total cholesterol and triglycerides (P<0.05).

CONCLUSION

The exosomal miRNA expression profile and signaling pathways related to T2DM intestinal damp-heat syndrome and the efficacy of GQD were established, which provides an alternative strategy for precision traditional Chinese medicine treatment.

Epigenetic clock analysis and increased plasminogen activator inhibitor-1 in high-functioning autism spectrum disorder

Background

Autism spectrum disorder (ASD) is characterized by impaired social communication and behavioral problems. An increased risk of premature mortality has been observed in individuals with ASD. Therefore, we hypothesized that biological aging is accelerated in individuals with ASD. Recently, several studies have established genome-wide DNA methylation (DNAm) profiles as ‘epigenetic clocks’ that can estimate biological aging. In addition, ASD has been associated with differential DNAm patterns.

Methods

We used two independent datasets from blood samples consisting of adult patients with high-functioning ASD and controls: the 1st cohort (38 ASD cases and 31 controls) and the 2nd cohort (6 ASD cases and 10 controls). We explored well-studied epigenetic clocks such as HorvathAge, HannumAge, SkinBloodAge, PhenoAge, GrimAge, and DNAm-based telomere length (DNAmTL). In addition, we investigated seven DNAm-based age-related plasma proteins, including plasminogen activator inhibitor-1 (PAI-1), and smoking status, which are the components of GrimAge.

Results

Compared to controls, individuals with ASD in the 1st cohort, but not in the 2nd cohort, exhibited a trend for increased GrimAge acceleration and a significant increase of PAI-1 levels. A meta-analysis showed significantly increased PAI-1 levels in individuals with ASD compared to controls.

Conclusion

Our findings suggest there is no epigenetic age acceleration in the blood of individuals with ASD. However, this study provides novel evidence regarding increased plasma PAI-1 levels in individuals with high-functioning ASD. These findings suggest PAI-1 may be a biomarker for high-functioning ASD, however, larger studies based on epigenetic clocks and PAI-1 will be necessary to confirm these findings.

Micro ribonucleic acid-363 regulates the phosphatidylinositol 3-kinase/threonine protein kinase axis by targeting NOTCH1 and forkhead box C2, leading to hepatic glucose and lipids metabolism disorder in type 2 diabetes mellitus

AIMS/INTRODUCTION

Glucose metabolic disorder is the main cause for type 2 diabetes progression. Exploring the molecular mechanisms of metabolic disorder are crucial for type 2 diabetes treatment.

MATERIALS AND METHODS

Micro ribonucleic acid (miR)-363, NOTCH1 and forkhead box C2 (FOXC2) expressions in high glucose (HG)-treated HepG2 cells and the livers of type 2 diabetes mellitus rats were assessed using quantitative polymerase chain reaction. Protein levels of NOTCH1, FOXC2 and phosphatidylinositol 3-kinase (PI3K)/serine/threonine protein kinase (Akt)-related proteins were evaluated using western blot. Lipid accumulation was determined using Oil Red O staining. Then glucose consumption, blood glucose level and glycogen content were detected using kits. Finally, dual luciferase reporter assay was used to verify the binding relationship between miR-363 and NOTCH1, and the binding relationship between miR-363 and FOXC2.

RESULTS

MiR-363 was significantly upregulated in the livers of diabetic rats and HG-induced HepG2 cells, whereas NOTCH1 and FOXC2 were downregulated. In HG-induced HepG2 cells, miR-363 inhibitor markedly increased glucose consumption and uptake, and reduced accumulation of lipid droplets. Then NOTCH1 and FOXC2 were identified as downstream targets of miR-363. NOTCH1 overexpression or FOXC2 overexpression could ameliorate glucose and lipids metabolism disorder in type 2 diabetes model cells. In addition, we found that FOXC2 inhibition abolished the effect of NOTCH1 overexpression on HG-induced HepG2 cells. Finally, we proved that the PI3K/Akt pathway was the downstream pathway of FOXC2.

CONCLUSION

MiR-363 was considered as a key regulator of glucose and lipids metabolism in type 2 diabetes mellitus, which regulated PI3K/Akt axis by targeting NOTCH1 and FOXC2, thus leading to hepatic glucose and lipids metabolism disorder in type 2 diabetes.

Delayed maturation of P2 flash visual evoked potential (VEP) latency in newborns of gestational diabetic mothers

BACKGROUND

The prevalence of gestational diabetes mellitus (GDM) has rapidly increased, yet few prior studies have investigated parameters of early brain development in infants born to gestational diabetic mothers. The present study assessed visual evoked potentials (VEPs) in healthy infants born to gestational diabetic mothers and matched controls.

METHODS

After exclusions, in this prospective study we examined VEPs in 73 neonates between 37 weeks and 41 weeks gestation at birth (n = 37 infants of gestational diabetic mothers). Stroboscopic flashes were presented through closed eyelids during passive electroencephalography (EEG) recording to derive VEP waveforms during natural sleep.

RESULTS

There was a statistically significant moderate correlation between gestational age at birth and P2 latency of the flash VEP where P2 latency significantly decreased with increasing gestational age (Pearson's R(73) = -0.32, p < .01). There was also a significant moderate correlation between postnatal age (hours of life) and P2 latency of the flash VEP where P2 latency significantly decreased with increasing postnatal age (Pearson's R(73) = -0.23, p < .05). When controlling for gestational age at birth, postnatal age, and sex, there was a significant effect of group (GDM-exposed vs. control) on P2 latency of the flash VEP (p < .05). Infants of gestational diabetic mothers had a significantly longer P2 latency (M: 215.29 ± SD: 2.58 ms) than controls (M: 206.41 ± SD: 2.62 ms).

CONCLUSION

Our findings suggest P2 flash VEP latency is a potential measure of cortical maturation and marker of immature development in infants of gestational diabetic mothers.

Effect of Insulin-Regulated FOXC2 Expression in Adipocyte Differentiation and Insulin Resistance

OBJECTIVE

1) To investigate the effect of FOXC2 on the differentiation of adipose-derived mesenchymal stem cells. 2) To analyze the mechanism between FOXC2 expression regulation in adipose differentiation and insulin resistance (IR).

METHODS

We first amplified the FOXC2 promoter region-512 and cloned it into the luciferase expression vector. The reporter gene system was transfected into the adipose tissue-derived mesenchymal stem cell to study insulin-mediated FOXC2 expression. We also manipulated FOXC2 protein expression by either siRNA or overexpression and studied the differentiation capability of adipose tissue-derived mesenchymal stem cell into adipocytes, as well as the influence on several IR-related genes: GLUT4, PPARγ, UCP1 and PAI-1.

RESULTS

1) Insulin effectively induced the expression of FOXC2 protein in adipose tissue-derived mesenchymal stem cells under differentiation (P<0.01). Insulin also induced FOXC2-pro-512T promoter activity significantly (P<0.01). 2) The stem cell adipose differentiation decreased in the FOXC2 overexpression group. 3) When FOXC2 was overexpressed, the expression of GLUT4, PAI-1 and UCP1 was higher than control groups (p<0.001). When FOXC2 was down-regulated by siRNA, both GLUT4 and PAI-1's protein expression were decreased (p<0.001), and the protein expression of PPARγ was increased (p<0.001). In the presence of insulin induction, overexpression of FOXC2 led to significantly higher UCP-1 expression (p<0.001) and lower PAI-1 expression (p<0.001). The protein expression of GLUT4, PAI-1 (p<0.001) and UCP-1 (p<0.05) was decreased in cells transfected with FOXC2 siRNA.

CONCLUSION

Insulin effectively induced the expression of FOXC2 protein in adipose tissue-derived mesenchymal stem cells under differentiation, possibly through the regulation of the FOXC2-pro-512T promoter activity. The different protein expression of FOXC2 has regulatory effects on several genes related to insulin resistance. FOXC2 is an important regulatory factor in adipocyte differentiation and insulin resistance.

Autism spectrum disorders: let's talk about glucose?

Autism spectrum disorders (ASD) are characterized by disconnectivity due to disordered neuronal migration, and by neuronal mitochondrial dysfunction. Different pathways involved in neuronal migration are affected by intrauterine hyperglycemia and hyperinsulinemia, while prolonged neonatal hypoglycemia may cause mitochondrial dysfunction. Our hypothesis was that conditions leading to intrauterine hyperglycemia or neonatal hypoglycemia would influence ASD pathogenesis. In this study, we identified risk factors for ASD by searching PubMed with the MeSH terms "autism spectrum disorder" and "risk factors". We then analyzed the relationship between the risk factors and glucose abnormalities in the mother and the offspring. The relationship between glucose abnormalities and risk factors such as obesity, excessive maternal weight gain, or diabetes mellitus is evident. For risk factors such as malformations or exposure to selective serotonin reuptake inhibitors, the relationship is speculative. In rodents, for example, intrauterine hyperglycemia is associated with malformations, independent of maternal diabetes. In their turn, selective serotonin reuptake inhibitors reduce the signs of neonatal hypoglycemia. Going undetected, prolonged hypoglycemia may harm the neonatal brain. Importantly, our group demonstrated that either high-carbohydrate diets or physical inactivity the day before delivery may influence neonatal glycemia. In that study, of 158 neonates selected to be screened according to maternal lifestyle risk factors, 48 had hypoglycemia. Of note, five of them had not been identified with current screening programs. Controlled studies are needed to clarify whether maternal interventions aiming at maintaining glycemic control, together with screening programs for neonatal hypoglycemia based on maternal lifestyle risk factors and on exposure to specific prenatal medications can reduce the prevalence of ASD.

The Vasculature in Prediabetes

The frequency of prediabetes is increasing as the prevalence of obesity rises worldwide. In prediabetes, hyperglycemia, insulin resistance, and inflammation and metabolic derangements associated with concomitant obesity cause endothelial vasodilator and fibrinolytic dysfunction, leading to increased risk of cardiovascular and renal disease. Importantly, the microvasculature affects insulin sensitivity by affecting the delivery of insulin and glucose to skeletal muscle; thus, endothelial dysfunction and extracellular matrix remodeling promote the progression from prediabetes to diabetes mellitus. Weight loss is the mainstay of treatment in prediabetes, but therapies that improved endothelial function and vasodilation may not only prevent cardiovascular disease but also slow progression to diabetes mellitus.

t-Darpp overexpression in HER2-positive breast cancer confers a survival advantage in lapatinib

Drug resistance is a major barrier to successful cancer treatment. For patients with HER2-positive breast cancer who initially respond to therapy, the majority develop resistance within one year of treatment. Patient outcomes could improve significantly if we can find and exploit common mechanisms of acquired resistance to different targeted therapies. Overexpression of t-Darpp, a truncated form of the dual kinase/phosphatase inhibitor Darpp-32, has been linked to acquired resistance to trastuzumab, a front-line therapy for HER2-positive breast cancer. Darpp-32 reverses t-Darpp's effect on trastuzumab resistance. In this study, we examined whether t-Darpp could be involved in resistance to lapatinib, another HER2-targeted therapeutic. Lapatinib-resistant SKBR3 cells (SK/LapR) showed a marked change in the Darpp-32:t-Darpp ratio toward a predominance of t-Darpp. Overexpression of t-Darpp alone was not sufficient to confer lapatinib resistance, but cells that overexpress t-Darpp partially mimicked the molecular resistance phenotype observed in SK/LapR cells exposed to lapatinib. SK/LapR cells failed to down-regulate Survivin and failed to induce BIM accumulation in response to lapatinib; cells overexpressing t-Darpp exhibited only the failed BIM accumulation. t-Darpp knock-down reversed this phenotype. Using a fluorescence-based co-culture system, we found that cells overexpressing t-Darpp formed colonies in lapatinib within 3-4 weeks, whereas parental cells in the same co-culture did not. Overall, t-Darpp appears to mediate a survival advantage in lapatinib, possibly linked to failed lapatinib-induced BIM accumulation. t-Darpp might also be relevant to acquired resistance to other cancer drugs that rely on BIM accumulation to induce apoptosis.

High glucose and insulin enhance uPA expression, ROS formation and invasiveness in breast cancer-derived cells

BACKGROUND

Accumulating evidence indicates that type 2 diabetes is associated with an increased risk to develop breast cancer. This risk has been attributed to hyperglycemia, hyperinsulinemia and chronic inflammation. As yet, however, the mechanisms underlying this association are poorly understood. Here, we studied the effect of high glucose and insulin on breast cancer-derived cell proliferation, migration, epithelial-mesenchymal transition (EMT) and invasiveness, as well as its relationship to reactive oxygen species (ROS) production and the plasminogen activation system.

METHODS

MDA-MB-231 cell proliferation, migration and invasion were assessed using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), scratch-wound and matrigel transwell assays, respectively. ROS production was determined using 2' 7'-dichlorodihydrofluorescein diacetate. The expression of E-cadherin, vimentin, fibronectin, urokinase plasminogen activator (uPA), its receptor (uPAR) and its inhibitor (PAI-1) were assessed using qRT-PCR and/or Western blotting assays, respectively. uPA activity was determined using gel zymography.

RESULTS

We found that high glucose stimulated MDA-MB-231 cell proliferation, migration and invasion, together with an increased expression of mesenchymal markers (i.e., vimentin and fibronectin). These effects were further enhanced by the simultaneous administration of insulin. In both cases, the invasion and growth responses were found to be associated with an increased expression of uPA, uPAR and PAI-1, as well as an increase in active uPA. An osmolality effect of high glucose was excluded by using mannitol at an equimolar concentration. We also found that all changes induced by high glucose and insulin were attenuated by the anti-oxidant N-acetylcysteine (NAC) and, thus, depended on ROS production.

CONCLUSIONS

From our data we conclude that hyperglycemia and hyperinsulinemia can promote breast cancer cell proliferation, migration and invasion. We found that these features were associated with increased expression of the mesenchymal markers vimentin and fibronectin, as well as increased uPA expression and activation through a mechanism mediated by ROS.

Statins Increase Plasminogen Activator Inhibitor Type 1 Gene Transcription through a Pregnane X Receptor Regulated Element

Plasminogen activator inhibitor type 1 (PAI-1) is a multifunctional protein that has important roles in inflammation and wound healing. Its aberrant regulation may contribute to many disease processes such as heart disease. The PAI-1 promoter is responsive to multiple inputs including cytokines, growth factors, steroids and oxidative stress. The statin drugs, atorvastatin, mevastatin and rosuvastatin, increased basal and stimulated expression of the PAI-1 promoter 3-fold. A statin-responsive, nuclear hormone response element was previously identified in the PAI-1 promoter, but it was incompletely characterized. We characterized this direct repeat (DR) of AGGTCA with a 3-nucleotide spacer at -269/-255 using deletion and directed mutagenesis. Deletion or mutation of this element increased basal transcription from the promoter suggesting that it repressed PAI-1 transcription in the unliganded state. The half-site spacing and the ligand specificity suggested that this might be a pregnane X receptor (PXR) responsive element. Computational molecular docking showed that atorvastatin, mevastatin and rosuvastatin were structurally compatible with the PXR ligand-binding pocket in its agonist conformation. Experiments with Gal4 DNA binding domain fusion proteins showed that Gal4-PXR was activated by statins while other DR + 3 binding nuclear receptor fusions were not. Overexpression of PXR further enhanced PAI-1 transcription in response to statins. Finally, ChIP experiments using Halo-tagged PXR and RXR demonstrated that both components of the PXR-RXR heterodimer bound to this region of the PAI-1 promoter.

The PAX3-FOXO1 fusion protein present in rhabdomyosarcoma interferes with normal FOXO activity and the TGF-β pathway

PAX3-FOXO1 (PAX3-FKHR) is the fusion protein produced by the genomic translocation that characterizes the alveolar subtype of Rhabdomyosarcoma, a pediatric sarcoma with myogenic phenotype. PAX3-FOXO1 is an aberrant but functional transcription factor. It retains PAX3-DNA-binding activity and functionally overlaps PAX3 function while also disturbing it, in particular its role in myogenic differentiation. We herein show that PAX3-FOXO1 interferes with normal FOXO function. PAX3-FOXO1 affects FOXO-family member trans-activation capability and the FOXO-dependent TGF-β response. PAX3-FOXO1 may contribute to tumor formation by inhibiting the tumor suppressor activities which are characteristic of both FOXO family members and TGF-β pathways. The recognition of this mechanism raises new questions about how FOXO family members function.

Clinical mesenchymal stromal cell products undergo functional changes in response to freezing

BACKGROUND AIMS

Current methods of mesenchymal stromal cell (MSC) cryopreservation result in variable post-thaw recovery and phenotypic changes caused by freezing. The objective of this investigation was to determine the influence of ex vivo cell expansion on phenotype of MSCs and the response of resulting phenotypes to freezing and thawing.

METHODS

Human bone marrow aspirate was used. MSCs were isolated and cells were assessed for total count, viability, apoptosis and senescence over 6 passages (8-10 doublings/passage) in ex vivo culture. One half of cells harvested at each passage were re-plated for continued culture and the other half were frozen at 1°C/min in a controlled-rate freezer. Frozen samples were stored in liquid nitrogen, thawed and reassessed for total cell count, viability and senescence immediately and 48 h after thaw.

RESULTS

Viability did not differ significantly between samples before freeze or after thaw. Senescence increased over time in pre-freeze culture and was significantly higher in one sample that had growth arrest both before freeze and after thaw. Freezing resulted in similar initial post-thaw recovery in all samples, but 48-h post-thaw growth arrest was observed in the sample with high senescence only.

CONCLUSIONS

High pre-freeze senescence appears to correlate with poor post-thaw function in MSC samples, but additional studies are necessary to obtain a sample sizes large enough to quantify results.

A role for tissue plasminogen activator in thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disease characterized by generalized microvascular occlusion. TTP has been related to severe deficiency of ADAMTS13, an enzyme that cleaves von Willebrand factor multimers into less adhesive molecules. However, ADAMTS13 deficiency correlates poorly with severity of thrombocytopenia or microangiopathic hemolysis, with the frequency of neurologic complications or the response to plasma exchange. Also, some patients with severe hereditary ADAMTS13 deficiency consistently relapse every few weeks, whereas others remain asymptomatic into their forties. Taken together, these findings suggest that an additional element is missing in the pathophysiology of TTP. We postulate that both low ADAMTS13 activity and low tissue-plasminogen activator activity are required to trigger TTP attacks. Tissue-plasminogen activator end product, plasmin, extensively degrades von Willebrand factor, breaking-down the bonds between platelets and the blood vessel wall, so that low tissue-plasminogen activator activity prevents a mechanism similar to that of ADAMTS13. The hypothesis that low tissue-plasminogen activator activity plays an important role in TTP pathogenesis is further substantiated by TTP comorbidity. Problems prevalent in patients with TTP attacks or with long-term TTP remission, including increased body mass index, major depression, cognitive abnormalities, hypertension, and premature death, are somehow associated with low tissue-plasminogen activator activity.

Effect of linagliptin compared with glimepiride on postprandial glucose metabolism, islet cell function and vascular function parameters in patients with type 2 diabetes mellitus receiving ongoing metformin treatment

BACKGROUND

The goal of this study was to investigate the effects of linagliptin compared with glimepiride on alpha and beta cell function and several vascular biomarkers after a standardized test meal.

METHODS

Thirty-nine patients on metformin alone (age, 64 ± 7 years; duration of type 2 diabetes mellitus, 7.8 ± 4.5years, 27 male, 12 female; HbA1c , 57.2 ± 6.9 mmol/mol; mean ± SD) were randomized to receive linagliptin 5 mg (n = 19) or glimepiride (n = 20) for a study duration of 12 weeks. Glucagon-like peptide 1, blood glucose, insulin, intact proinsulin, glucagon, plasminogen activator inhibitor-1 (PAI-1), cyclic guanosinmonophosphat and asymetric dimethylarginin levels were measured in the fasting state and postprandial at 30-min intervals for a duration of 5 h. The areas under the curve (AUC0-300 min ) were calculated for group comparisons.

RESULTS

HbA1c , fasting and postprandial glucose levels improved in both groups. An increase in postprandial insulin (22595 ± 5984 pmol/L*min), postprandial intact proinsulin (1359 ± 658 pmol/L*min), postprandial glucagon (317 ± 1136 pg/mL*min) and postprandial PAI-1 levels (863 ± 467 ng/mL*min) could be observed during treatment with glimepiride, whereas treatment with linagliptin was associated with a decrease in postprandial insulin (-8007 ± 4204 pmol/L*min), intact proinsulin (-1771 ± 426 pmol/L*min), postprandial glucagon (-1597 ± 1831 pg/mL*min) and PAI-1 levels (-410 ± 276 ng/mL*min).

CONCLUSIONS

Despite an improvement in blood glucose control in both groups, linagliptin reduced postprandial insulin, proinsulin, glucagon and PAI-levels. These results indicate an improvement in postprandial alpha and beta cell function, as well as a reduced postprandial vascular risk profile during treatment with linagliptin.

Forkhead box A1 (FOXA1) is a key mediator of insulin-like growth factor I (IGF-I) activity

The insulin-like growth factor receptor (IGF-IR) has been implicated in a number of human tumors, including breast cancer. Data from human breast tumors has demonstrated that IGF-IR is over-expressed and hyper-phosphorylated. Additionally, microarray analysis has shown that IGF-I treatment of MCF7 cells leads to a gene signature comprised of induced and repressed genes, which correlated with luminal B tumors. FOXA1, a forkhead family transcription factor, has been shown to be crucial for mammary ductal morphogenesis, similar to IGF-IR, and expressed at high levels in luminal subtype B breast tumors. Here, we investigated the relationship between FOXA1 and IGF-I action in breast cancer cells. We show that genes regulated by IGF-I are enriched for FOXA1 binding sites, and knock down of FOXA1 blocked the ability of IGF-I to regulate gene expression. IGF-I treatment of MCF7 cells increased the half-life of FOXA1 protein and this increase in half-life appeared to be dependent on canonical IGF-I signal transduction through both MAPK and AKT pathways. Finally, knock down of FOXA1 led to a decreased ability of IGF-I to induce proliferation and protect against apoptosis. Together, these results demonstrate that IGF-I can increase the stability of FOXA1 protein expression and place it as a critical mediator of IGF-I regulation of gene expression and IGF-I-mediated biological responses.

FOXO4 induces human plasminogen activator inhibitor-1 gene expression via an indirect mechanism by modulating HIF-1alpha and CREB levels

The plasminogen activator inhibitor-1 (PAI-1) expression can be enhanced by hypoxia and various stimuli associated with oxidative stress. Among the FOXO transcription factors, FOXO4 appears to be crucial in the response against oxidative stress. Therefore, it was the aim of this study to investigate the role of peroxide-induced oxidative stress and FOXO4 on PAI-1 expression under normoxia and hypoxia. Treatment of cells with hydrogen peroxide increased PAI-1 mRNA, protein, and promoter activity, and knocking down FOXO4 abolished the peroxide-dependent PAI-1 induction. PAI-1 promoter reporter gene assays revealed that the peroxide and FOXO4-dependent induction was mediated through the HIF-1 and CREB-binding HRE within the PAI-1 promoter. Western blot analyses then indicated that peroxide and FOXO4 downregulated HIF-1alpha levels, whereas CREB levels were increased. Chromatin immunoprecipitations showed that FOXO4 did not bind the PAI-1 promoter, whereas CREB binding was enhanced on FOXO4 overexpression. In addition, knockdown of CREB abolished the FOXO4-mediated PAI-1 induction. Together, these findings provide the first evidence that oxidative stress and FOXO4 induce PAI-1 expression through an indirect mechanism involving modulation of HIF-1alpha and CREB protein levels and that enhanced CREB binding to the PAI-1 promoter is critical for the PAI-1 induction under oxidative stress.