TNF-α induces acyl-CoA synthetase 3 to promote lipid droplet formation in human endothelial cells.

Chronic inflammation contributes to cardiovascular disease. Increased levels of the inflammatory cytokine, TNF-α, are often present in conditions associated with cardiovascular disease risk, and TNF-α induces a number of pro-atherogenic effects in macrovascular endothelial cells, including expression of adhesion molecules and chemokines, and lipoprotein uptake and transcytosis to the subendothelial tissue. However, little is known about the roles of acyl-CoA synthetases (ACSLs), enzymes that esterify free fatty acids into their acyl-CoA derivatives, or about the effects of TNF-α on ACSLs in endothelial cells. Therefore, we investigated the effects of TNF-α on ACSLs and downstream lipids in cultured human coronary artery endothelial cells and human umbilical vein endothelial cells. We demonstrated that TNF-α induces ACSL1, ACSL3, and ACSL5, but not ACSL4, in both cell types. TNF-α also increased oleoyl-CoA levels, consistent with the increased ACSL3 expression. RNA-sequencing demonstrated that knockdown of ACSL3 had no marked effects on the TNF-α transcriptome. Instead, ACSL3 was required for TNF-α-induced lipid droplet formation in cells exposed to oleic acid. These results demonstrate that increased acyl-CoA synthesis as a result of ACSL3 induction is part of the TNF-α response in human macrovascular endothelial cells.

Fimasartan increases glucose-stimulated insulin secretion in patients with type 2 diabetes and hypertension compared with amlodipine.

AIM: To study the effects of angiotensin receptor blockers (ARBs) on insulin secretion in hypertensive patients with type 2 diabetes. MATERIALS AND METHODS: A total of 41 patients were enrolled in this open-label, active comparator-controlled, crossover study. After a 2-week run-in period with amlodipine, the participants were assigned to receive either fimasartan (60-120 mg daily) or amlodipine (5-10 mg daily) for 16 weeks. Thereafter, they were treated with the other drug for another 16 weeks. Physical examinations and laboratory tests were performed before and after each treatment. RESULTS: Blood pressure, glycated haemoglobin and oral glucose tolerance test (OGTT) values were similar with each treatment. Fimasartan treatment significantly increased median (range) homeostatic assessment of ß-cell function values (49.9 [22.5-174.4] vs 46.9 [15.6-148.0]), area under the curve of insulin during OGTT (27 284 [9501-94 525] vs 26 818 [8112-76 704] pmol/L × min), insulinogenic index at 60 minutes (19.7 [3.0-131.2] vs 15.0 [2.4-103.8] pmol/mmol) and at 120 minutes (19.1 [1.9-85.5] vs 12.6 [-4.3-178.8] pmol/mmol) compared with those with amlodipine (all P < .05); however, acute insulin response and insulin resistance indices were similar for both agents. CONCLUSIONS: Compared with amlodipine, fimasartan increased late-phase glucose-stimulated insulin secretion in patients with type 2 diabetes and hypertension. This finding suggests that ARBs would be more beneficial in such patients compared with other classes of anti-hypertensives.

EX4 stabilizes and activates Nrf2 via PKCδ, contributing to the prevention of oxidative stress-induced pancreatic beta cell damage.

Oxidative stress in pancreatic beta cells can inhibit insulin secretion and promote apoptotic cell death. Exendin-4 (EX4), a glucagon-like peptide-1 receptor agonist, can suppress beta cell apoptosis, improve beta cell function and protect against oxidative damage. In this study, we investigated the molecular mechanisms for antioxidative effects of EX4 in pancreatic beta cells. INS-1 cells, a rat insulinoma cell line, were pretreated with EX4 and exposed to palmitate or H2O2. Reactive oxygen species (ROS) production, and glutathione and insulin secretion were measured. The mRNA and protein expression levels of antioxidant genes were examined. The level of nuclear factor erythroid 2-related factor 2 (Nrf2), its binding to antioxidant response element (ARE), and its ubiquination in the presence of EX4 were determined. The Nrf2 signaling pathway was determined using rottlerin (protein kinase [PK]Cδ inhibitor), H89 (PKA inhibitor) and LY294002 (phosphatidylinositide 3-kinase [PI3K] inhibitor). EX4 treatment decreased ROS production, recovered cellular glutathione levels and insulin secretion in the presence of oxidative stress in INS-1 cells. The expression levels of glutamate-cysteine ligase catalytic subunit and heme oxygenase-1 were increased by EX4 treatment. EX4 promoted Nrf2 translocation, ARE binding activity and enhanced stabilization of Nrf2 by inhibition of ubiquitination. Knockdown of Nrf2 abolished the effect of EX4 on increased insulin secretion. Inhibition of PKCδ attenuated Nrf2 translocation and antioxidative gene expression by EX4 treatment. We suggest that EX4 activates and stabilizes Nrf2 through PKCδ activation, contributing to the increase of antioxidant gene expression and consequently improving beta cell function in the presence of oxidative stress.

Metabolic effect of pancreatoduodenectomy: Resolution of diabetes mellitus after surgery.

BACKGROUND: It is considered natural that glucose tolerance worsens after pancreatectomy. However, diabetes mellitus (DM) resolves after metabolic bypass surgery and anatomic changes after PD resemble those after metabolic surgery. This study assessed the incidence of DM resolution after pancreatectomy and differences in metabolic parameters following pancreatoduodenectomy (PD) and distal pancreatectomy (DP). METHODS: Between 2007 and 2013, 218 consecutive patients with pancreatic diseases underwent PD (n = 112) or DP (n = 106) at Seoul National University Hospital. Factors associated with changes in glucose homeostasis were evaluated by assaying serum glucose concentrations in prospectively collected samples. RESULTS: Of the 218 patients, 88 (40.4%) had preoperative DM, with 27 (30.7%) of the latter showing postoperative resolution of DM, a rate significantly higher in patients who had undergone PD than DP (40.4% vs. 12.9%, p = 0.008). Fasting blood glucose (p = 0.001), PP2 (p < 0.001), and HOMA-IR (p = 0.005) significantly decreased after PD but not after DP. Multivariate analysis revealed that PD was independently associated with DM resolution (odds ratio 7.790, p = 0.003). PD was associated with a significantly higher DM resolution rate than DP among the 37 pancreatic cancer patients with preoperative DM (34.6% vs. 0%, p = 0.036). DM resolution rates were similar in pancreatic cancer and other pancreatic diseases (p = 0.419). CONCLUSION: More than 40% of patients with preoperative DM show resolution after PD. Decreased insulin resistance and suspected enhanced glucose stimulated insulin secretion decreasing PP2 seem to contribute improved glucose homeostasis after PD. BMI was unrelated to DM resolution, indicating that PD-associated physio-anatomical changes may help resolve DM independent of weight.

FLOWERING LOCUS T has higher protein mobility than TWIN SISTER OF FT.

In plants, successful reproduction requires the proper timing of flowering under changing environmental conditions. Arabidopsis FLOWERING LOCUS T (FT), which encodes a proposed phloem-mobile florigen, has a close homologue, TWIN SISTER OF FT (TSF). During the vegetative phase, TSF shows high levels of expression in the hypocotyl before FT induction, but the tsf mutation does not have an apparent flowering-time phenotype on its own under long-day conditions. This study compared the protein mobility of FT and TSF. With TSF-overexpressing plants as the rootstock, the flowering time of ft tsf scion plants was only slightly accelerated. Previous work has shown that FT is graft-transmissible; by contrast, this study did not detect movement of TSF from the roots into the shoot of the scion plants. This study used plants overexpressing FT/TSF chimeric proteins to map a region responsible for FT movement. A chimeric TSF with region II of FT (L28 to G98) expressed in the rootstock caused early flowering in ft tsf scion plants; movement of the chimeric protein from the rootstocks into the shoot apical region of the ft tsf scion plants was also detected. Misexpression of TSF in the leaf under the control of the FT promoter or grafting of 35S::TSF cotyledons accelerated flowering of ft-10 plants. FT was more stable than TSF. Taking these results together, we propose that protein mobility of FT is higher than that of TSF, possibly due to a protein domain that confers mobility and/or protein stability.

Novel strategy for successful long-term hematopoietic recovery after transplanting a limited number of hematopoietic stem/progenitor cells.

Various investigators have attempted to overcome the shortage of available hematopoietic stem/progenitor cells (HSPCs) by facilitating their engraftment after transplantation. Preconditioning of HSPCs with the granulocyte-derived cationic peptide LL-37 has been suggested as a useful strategy to facilitate engraftment of transplanted cells by enhancing their responsiveness to CXCL12. In this study, we evaluated whether LL-37 preconditioning is acceptable for clinical application. We found that the effect of LL-37 preconditioning was specific to clonogenic cells and was mediated specifically by increased calcium influx with the activation of downstream signaling through mammalian target of rapamycin complex 1 (mTORC1). Because hyperactivation of mTORC1 and the disruption of 5' adenosine monophosphate-activated protein kinase (AMPK) are known to deplete HSPC pools, we compared the repopulation capacity of HSPCs preconditioned with LL-37 and those preconditioned with AMPK activator (AICAR). In vivo competitive repopulation experiments revealed that LL-37 preconditioning impairs long-term repopulation of transplanted HSPCs, suggesting that this strategy might not acceptable for clinical applications in which long-term repopulation capacity is a prerequisite. AICAR preconditioning dramatically enhanced the long-term repopulation of transplanted HSPCs, however. Taken together, these results suggest that future strategies to ensure successful transplantation outcomes should focus on protecting HSPCs from various stimuli during their homing to the bone marrow niches rather than activating them before transplantation.

Magnetosome-like ferrimagnetic iron oxide nanocubes for highly sensitive MRI of single cells and transplanted pancreatic islets.

For ultrasensitive magnetic resonance imaging (MRI), magnetic nanoparticles with extremely high r2 relaxivity are strongly desired. Magnetosome-like nanoparticles were prepared by coating polyethylene glycol-phospholipid (PEG-phospholipid) onto ferrimagnetic iron oxide nanocubes (FIONs). FIONs exhibited a very high relaxivity (r2) of 324 mM(-1) s(-1), allowing efficient labeling of various kinds of cells. The magnetic resonance (MR) imaging of single cells labeled with FIONs is demonstrated not only in vitro but also in vivo. Pancreatic islet grafts and their rejection could be imaged using FIONs on a 1.5 T clinical MRI scanner. The strong contrast effect of FIONs enabled MR imaging of transplanted islets in small rodents as well as in large animals. Therefore, we expect that MR imaging of pancreatic islet grafts using FIONs has the potentials for clinical applications. Furthermore, FIONs will enable highly sensitive noninvasive assessment after cell transplantation.

Glucolipotoxicity Suppressed Autophagy and Insulin Contents in Human Islets, and Attenuation of PERK Activity Enhanced Them in an ATG7-Dependent Manner.

BACKGRUOUND: Administration of pancreatic endoplasmic reticulum kinase inhibitor (PERKi) improved insulin secretion and hyperglycemia in obese diabetic mice. In this study, autophagic balance was studied whether to mediate it. METHODS: Human islets were isolated from living patients without diabetes. PERKi GSK2606414 effects were evaluated in the islets under glucolipotoxicity by palmitate. Islet insulin contents and secretion were measured. Autophagic flux was assessed by microtubule associated protein 1 light chain 3 (LC3) conversion, a red fluorescent protein (RFP)-green fluorescent protein (GFP)- LC3 tandem assay, and P62 levels. For mechanical analyses, autophagy was suppressed using 3-methyladenine in mouse islets. Small interfering RNA for an autophagy-related gene autophagy related 7 (Atg7) was transfected to interfere autophagy. RESULTS: PERKi administration to mice decreased diabetes-induced P62 levels in the islets. Glucolipotoxicity significantly increased PERK phosphorylation by 70% and decreased insulin contents by 50% in human islets, and addition of PERKi (40 to 80 nM) recovered both. PERKi also enhanced glucose-stimulated insulin secretion (6-fold). PERKi up-regulated LC3 conversion suppressed by glucolipotoxicity, and down-regulated P62 contents without changes in P62 transcription, indicating enhanced autophagic flux. Increased autophagosome-lysosome fusion by PERKi was visualized in mouse islets, where PERKi enhanced ATG7 bound to LC3. Suppression of Atg7 eliminated PERKi-induced insulin contents and secretion. CONCLUSION: This study provided functional changes of human islets with regard to autophagy under glucolipotoxicity, and suggested modulation of autophagy as an anti-diabetic mechanism of PERKi.

Pioglitazone as Add-on THERAPY in Patients with Type 2 Diabetes Mellitus Inadequately Controlled with Dapagliflozin and Metformin: Double-Blind, Randomized, Placebo-Controlled Trial.

Background: This study assessed the efficacy and safety of triple therapy with pioglitazone 15 mg add-on versus placebo in patients with type 2 diabetes mellitus (T2DM) inadequately controlled with metformin and dapagliflozin. Methods: In this multicenter, double-blind, randomized, phase 3 study, patients with T2DM with an inadequate response to treatment with metformin (≥1,000 mg/day) plus dapagliflozin (10 mg/day) were randomized to receive additional pioglitazone 15 mg/day (n=125) or placebo (n=125) for 24 weeks. The primary endpoint was the change in glycosylated hemoglobin (HbA1c) levels from baseline to week 24 (ClinicalTrials.gov identifier: NCT05101135). Results: At week 24, the adjusted mean change from baseline in HbA1c level compared with placebo was significantly greater with pioglitazone treatment (-0.47%; 95% confidence interval, -0.61 to -0.33; P<0.0001). A greater proportion of patients achieved HbA1c <7% or <6.5% at week 24 with pioglitazone compared to placebo as add-on to 10 mg dapagliflozin and metformin (56.8% vs. 28% for HbA1c <7%, and 23.2% vs. 9.6% for HbA1c <6.5%; P<0.0001 for all). The addition of pioglitazone also significantly improved triglyceride, highdensity lipoprotein cholesterol levels, and homeostatic model assessment of insulin resistance levels, while placebo did not. The incidence of treatment-emergent adverse events was similar between the groups, and the incidence of fluid retention-related side effects by pioglitazone was low (1.5%). Conclusion: Triple therapy with the addition of 15 mg/day of pioglitazone to dapagliflozin plus metformin was well tolerated and produced significant improvements in HbA1c in patients with T2DM inadequately controlled with dapagliflozin plus metformin.

Association between hypotension during pancreatectomy and development of postoperative diabetes.

CONTEXT: With advancements in long-term survival after pancreatectomy, post-pancreatectomy diabetes has become a concern, and the risk factors are not established yet. Pancreatic islets are susceptible to ischemic damage, though there is a lack of clinical evidence regarding glycemic deterioration. OBJECTIVE: To investigate association between hypotension during pancreatectomy and development of post-pancreatectomy diabetes. DESIGN: In this retrospective, longitudinal cohort study, we enrolled patients without diabetes who underwent distal pancreatectomy or pancreaticoduodenectomy between January 2005 and December 2018, from two referral hospitals in Korea. MAIN OUTCOME MEASURES: Intraoperative hypotension [IOH] was defined as a 20% or greater reduction in systolic blood-pressure. The primary and secondary outcomes were incident diabetes and postoperative Homeostatic Model Assessment [HOMA] indices. RESULTS: We enrolled 1,129 patients (average age, 59 years; 49% men; 35% distal pancreatectomy). IOH occurred in 83% (median duration, 25 minutes; interquartile range [IQR], 5-65). During a median follow-up of 3.9 years, diabetes developed in 284 patients (25%). The cumulative incidence of diabetes was proportional to increases in the duration and depth of IOH (P < 0.001). For the median duration in an IOH when compared to a reference time of 0 minute, the hazard ratio [HR] was 1.48 (95% CI, 1.14-1.92). The effect was pronounced with distal pancreatectomy compared to pancreaticoduodenectomy. Furthermore, the duration of IOH was inversely correlated with 1-year HOMA beta-cell function (P < 0.002), but not with HOMA insulin resistance. CONCLUSIONS: These results support the hypothesis that IOH during pancreatectomy may elevate risk of diabetes by inducing beta cell insufficiency.

Changes in metabolic markers in insulin-producing ß-cells during hypoxia-induced cell death as studied by NMR metabolomics.

This study was designed to investigate changes in the metabolites in the intracellular fluid of the pancreatic ß-cell line INS-1 to identify potential early and late biomarkers for predicting hypoxia-induced cell death. INS-1 cells were incubated under normoxic conditions (95% air, 5% CO2) or hypoxic conditions (1% O2, 5% CO2, 95% N2) for 2, 4, 6, 12, or 24 h. The biological changes indicating the process of cell death were analyzed using the MTT assay, flow cytometry, Western blotting, and immunostaining. Changes in the metabolic profiles from cell lysates were identified using ¹H nuclear magnetic resonance (¹H NMR) spectroscopy, and the spectra were analyzed by the multivariate model Orthogonal Projections to Latent Structure-Discriminant Analysis. Cell viability decreased approximately 40% after 12-24 h of hypoxia, coincident with a high level of cleaved caspase-3. A high level of HIF-1α was detected in the 12-24 h hypoxic conditions. The metabolite profiles were altered according to the degree of exposure to hypoxia. A spectral analysis showed significant differences in creatine-containing compounds at the early stage (2-6 h) and taurine-containing compounds at the late stage (12-24 h), with the detection of HIF-1α and cleaved caspase-3 in cells exposed to hypoxia compared to normoxia. Glycerophosphocholine decreased during the early stage hypoxia. The change in taurine- and creatine-containing compounds and choline species could be involved in the ß-cell death process as inhibitors or activators of cell death. Our results imply that assessment by ¹H NMR spectroscopy would be a useful tool to predict the cell death process and to identify molecules regulating hypoxia-induced cell death mechanisms.

Prediction of type 2 diabetes in women with a history of gestational diabetes using a genetic risk score.

AIMS/HYPOTHESIS: Women with a history of gestational diabetes mellitus (GDM) are at increased risk of future development of type 2 diabetes. Recently, over 65 genetic variants have been confirmed to be associated with diabetes. We investigated whether this genetic information could improve the prediction of future diabetes in women with GDM. METHODS: This was a prospective cohort study consisting of 395 women with GDM who were followed annually with an OGTT. A weighted genetic risk score (wGRS), consisting of 48 variants, was assessed for improving discrimination (C statistic) and risk reclassification (continuous net reclassification improvement [NRI] index) when added to clinical risk factors. RESULTS: Among the 395 women with GDM, 116 (29.4%) developed diabetes during a median follow-up period of 45 months. Women with GDM who went on to develop diabetes had a significantly higher wGRS than those who did not (9.36 ± 0.92 vs 8.78 ± 1.07; p < 1.56 × 10(-7)). In a complex clinical model adjusted for age, prepregnancy BMI, family history of diabetes, blood pressure, fasting glucose and fasting insulin concentration, the C statistic marginally improved from 0.741 without the wGRS to 0.775 with the wGRS (p = 0.015). The addition of the wGRS to the clinical model resulted in a modest improvement in reclassification (continuous NRI 0.430 [95% CI 0.218, 0.642]; p = 7.0 × 10(-5)). CONCLUSIONS/INTERPRETATION: In women with GDM, who are at high risk of diabetes, the wGRS was significantly associated with the future development of diabetes. Furthermore, it improved prediction over clinical risk factors.

The cotyledons produce sufficient FT protein to induce flowering: evidence from cotyledon micrografting in Arabidopsis.

In Arabidopsis, long-distance movement of FLOWERING LOCUS T (FT) protein from the leaf to the shoot apex triggers flower development. In wild-type Arabidopsis plants under long-day conditions, FT is mainly expressed in the cotyledon but is weakly expressed in the first true leaf prior to floral induction. To test the importance of the cotyledon in floral induction, we developed a cotyledon micrografting (Cot-grafting) method that, unlike other grafting methods, allows the FT protein from the graft to be transported via its native route from leaves to the shoot apex. By using Cot-grafting, we found that grafting a single wild-type cotyledon onto an ft-10 mutant strongly suppressed the ft-10 late flowering phenotype. Neither Y-grafting wild-type shoots nor butt-grafting wild-type roots to ft-10 plants resulted in comparably accelerated flowering in the ft-10 recipient plants. ft-10 mutants grafted with a 35S::FT cotyledon flowered as early as wild-type plants. When phloem-specific tracers were applied to a donor cotyledon, the tracers were detected in the vein of the true leaf of recipient plants 6 d after Cot-grafting. Also, macromolecule trafficking of an FT:yellow fluorescent protein:hemagglutinin fusion occurred across the graft junction 6 d after Cot-grafting. These results suggest that Cot-grafting, which allows protein movement in a manner consistent with the natural flow of FT protein from the leaf to the shoot apex, can efficiently suppress the late flowering of ft-10 mutants. Our results further suggest that in Arabidopsis, the cotyledon is an important organ for producing FT protein to induce flowering.

Metformin-induced inhibition of the mitochondrial respiratory chain increases FGF21 expression via ATF4 activation.

Fibroblast growth factor 21 (FGF21) is an endocrine hormone that exhibits anti-obesity and anti-diabetes effects. Because metformin is widely used as a glucose-lowering agent in patients with type 2 diabetes (T2D), we investigated whether metformin modulates FGF21 expression in cell lines, and in mice or human subjects. We found that metformin increased the expression and release of FGF21 in a diverse set of cell types, including rat hepatoma FaO, primary mouse hepatocytes, and mouse embryonic fibroblasts (MEFs). Intriguingly, AMP-activated protein kinase (AMPK) was dispensable for the induction of FGF21 by metformin. Mammalian target of rapamycin complex 1 (mTORC1) and peroxisome proliferator-activated receptor α (PPARα), which are additional targets of metformin, were not involved in metformin-induced FGF21 expression. Importantly, inhibition of mitochondrial complex I activity by metformin resulted in FGF21 induction through PKR-like ER kinase (PERK)-eukaryotic translation factor 2α (eIF2α)-activating transcription factor 4 (ATF4). We showed that metformin activated ATF4 and increased FGF21 expression in the livers of mice, which led to increased serum levels of FGF21. We also found that serum FGF21 level was increased in human subjects with T2D after metformin therapy for 6 months. In conclusion, our results indicate that metformin induced expression of FGF21 through an ATF4-dependent mechanism by inhibiting mitochondrial respiration independently of AMPK. Therefore, FGF21 induction by metformin might explain a portion of the beneficial metabolic effects of metformin.

F-box only protein 9 is required for adipocyte differentiation.

The objective of this study is to investigate whether F-box only protein 9 (FBXO9), an ubiquitination E3 ligase, has a functional role in adipocyte differentiation. Expression of FBXO9 was compared between obese mice and control lean mice using real-time PCR. Also, expression pattern of FBXO9 was monitored during 3T3-L1 adipocyte differentiation. FBXO9 was highly expressed in obese mice, and increased in the early stages of adipogenesis. To verify a functional role of FBXO9 in adipogenesis, FBXO9 was knocked down using transfection of siRNAs against FBXO9 into 3T3-L1 cells during the induction of adipogenesis. Knockdown of FBXO9 in early stage of adipogenesis almost completely inhibited adipogenesis, and CCAAT/enhancer binding protein ß (C/EBPß) levels were significantly reduced. However, the cells stably expressing C/EBPß were fairly differentiated into adipocytes in the FBXO9 knockdown condition. These results suggest that FBXO9 is required for adipocyte differentiation, and C/EBPß plays a role in the effect of FBXO9 on adipogenesis.

The microRNA156-SQUAMOSA PROMOTER BINDING PROTEIN-LIKE3 module regulates ambient temperature-responsive flowering via FLOWERING LOCUS T in Arabidopsis.

The flowering time of plants is affected by modest changes in ambient temperature. However, little is known about the regulation of ambient temperature-responsive flowering by small RNAs. In this study, we show that the microRNA156 (miR156)-SQUAMOSA PROMOTER BINDING PROTEIN-LIKE3 (SPL3) module directly regulates FLOWERING LOCUS T (FT) expression in the leaf to control ambient temperature-responsive flowering. Overexpression of miR156 led to more delayed flowering at a lower ambient temperature (16°C), which was associated with down-regulation of FT and FRUITFULL expression. Among miR156 target genes, SPL3 mRNA levels were mainly reduced, probably because miR156-mediated cleavage of SPL3 mRNA was higher at 16°C. Overexpression of miR156-resistant SPL3 [SPL3(-)] caused early flowering, regardless of the ambient temperature, which was associated with up-regulation of FT and FRUITFULL expression. Reduction of miR156 activity by target mimicry led to a phenotype similar to that of SUC2::rSPL3 plants. FT up-regulation was observed after dexamethasone treatment in GVG-rSPL3 plants. Misexpression and artificial microRNA-mediated suppression of FT in the leaf dramatically altered the ambient temperature-responsive flowering of plants overexpressing miR156 and SPL3(-). Chromatin immunoprecipitation assay showed that the SPL3 protein directly binds to GTAC motifs within the FT promoter. Lesions in TERMINAL FLOWER1, SHORT VEGETATIVE PHASE, and EARLY FLOWERING3 did not alter the expression of miR156 and SPL3. Taken together, our data suggest that the interaction between the miR156-SPL3 module and FT is part of the regulatory mechanism controlling flowering time in response to ambient temperature.

Clinical characteristics of the responders to dipeptidyl peptidase-4 inhibitors in Korean subjects with type 2 diabetes.

We investigated characteristics associated with the efficacy of dipeptidyl peptidase-4 inhibitors (DPP4i) in Korean patients with type 2 diabetes. We reviewed medical records of 477 patients who had taken sitagliptin or vildagliptin longer than 40 weeks. Response to DPP4i was evaluated with HbA1c change after therapy (ΔHbA1c). The Student's t-test between good responders (GR: ΔHbA1c > 1.0%) and poor responders (PR: ΔHbA1c < 0.5%), a correlation analysis among clinical parameters, and a linear multivariate regression analysis were performed. The mean age was 60 yr, duration of diabetes 11 yr and HbA1c was 8.1%. Baseline fasting plasma glucose (FPG), HbA1c, C-peptide, and creatinine were significantly higher in the GR compared to the PR. Duration of diabetes, FPG, HbA1c, C-peptide and creatinine were significantly correlated with ΔHbA1c. In the multivariate analysis, age (r(2) = 0.006), duration of diabetes (r(2) = 0.019), HbA1c (r(2) = 0.296), and creatinine levels (r(2) = 0.024) were independent predictors for the response to DPP4i. Body mass index and insulin resistance were not associated with the response to DPP4i. In conclusion, better response to DPP4i would be expected in Korean patients with type 2 diabetes who have higher baseline HbA1c and creatinine levels with shorter duration of diabetes.

Partial Deletion of Perk Improved High-Fat Diet-Induced Glucose Intolerance in Mice.

Although pancreatic endoplasmic reticulum kinase (PERK) is indispensable to beta cells, low-dose PERK inhibitor improved glucose- stimulated insulin secretion (GSIS) and hyperglycemia in diabetic mice. Current study examined if partial deletion of Perk (Perk+/-) recapitulated the effects of PERK inhibitor, on the contrary to the complete deletion. Perk+/- mice and wild-type controls were fed with a high-fat diet (HFD) for 23 weeks. Glucose tolerance was evaluated along with serum insulin levels and islet morphology. Perk+/- mice on normal chow were comparable to wild-type mice in various metabolic features. HFD-induced obesity was not influenced by Perk reduction; however, HFD-induced glucose intolerance was significantly improved since 15-week HFD. HFD-induced compromises in GSIS were relieved by Perk reduction, accompanied by reductions in phosphorylated PERK and activating transcription factor 4 (ATF4) in the islets. Meanwhile, HFD-induced islet expansion was not significantly affected. In summary, partial deletion of Perk improved glucose tolerance and GSIS impaired by diet-induced obesity, without changes in body weights or islet mass.

Direct Differentiation of Bone Marrow Mononucleated Cells Into Insulin-Producing Cells Using 4 Specific Soluble Factors.

Bone marrow-derived stem cells are self-renewing and multipotent adult stem cells that differentiate into several types of cells. Here, we investigated a unique combination of 4 differentiation-inducing factors (DIFs), including putrescine (Put), glucosamine (GlcN), nicotinamide, and BP-1-102, to develop a differentiation method for inducing mature insulin-producing cells (IPCs) and apply this method to bone marrow mononucleated cells (BMNCs) isolated from mice. BMNCs, primed with the 4 soluble DIFs, were differentiated into functional IPCs. BMNCs cultured under the defined conditions synergistically expressed multiple genes, including those for PDX1, NKX6.1, MAFA, NEUROG3, GLUT2, and insulin, related to pancreatic beta cell development and function. They produced insulin/C-peptide and PDX1, as assessed using immunofluorescence and flow cytometry. The induced cells secreted insulin in a glucose-responsive manner, similar to normal pancreatic beta cells. Grafting BMNC-derived IPCs under kidney capsules of mice with streptozotocin (STZ)-induced diabetes alleviated hyperglycemia by lowering blood glucose levels, enhancing glucose tolerance, and improving glucose-stimulated insulin secretion. Insulin- and PDX1-expressing cells were observed in the IPC-bearing graft sections of nephrectomized mice. Therefore, this study provides a simple protocol for BMNC differentiation, which can be a novel approach for cell-based therapy in diabetes mellitus.

Prevalence of elevated glycated hemoglobin in women with polycystic ovary syndrome.

BACKGROUND: Recently, the American Diabetes Association (ADA) has included glycated hemoglobin A1(c) (A1C) level as a component of diagnostic criteria of 'diabetes' or 'increased risk for diabetes'. This study was conducted to examine the prevalence of and risk factors for 'elevated A1C' (≥5.7%) in women with polycystic ovary syndrome (PCOS). METHODS: A1C was measured using an immunoturbidimetric assay, and was evaluated in 154 patients with PCOS and 469 age-matched controls (match ratio of 1-3). All subjects were categorized by BMI (non-obese <25 kg/m(2) and obese ≥25 kg/m(2)), and the prevalence of elevated A1C was also analyzed according to BMI. RESULTS: One-third (31.2%) of the patients with PCOS had elevated A1C. The prevalence of elevated A1C (≥5.7%) was similar in obese women with PCOS and obese controls (23.5 and 20.0%, respectively, P= 1.0) but non-obese women with PCOS (mean age 29.8 ± 5.3 years) had a higher prevalence of elevated A1C than non-obese controls (31.2 versus 6.6%, respectively, P< 0.001). Logistic regression analysis of all subjects showed that the odds that a woman has elevated A1C was 6.7 times higher if she has PCOS (adjusted odds ratio 6.67, 95% confidence interval 3.50-12.70). CONCLUSIONS: The high prevalence of elevated A1C in non-obese patients with PCOS and an increased risk of elevated A1C associated with PCOS suggest that PCOS itself may be associated with abnormal A1C status. Assessing A1C level in young, non-obese patients with PCOS may be a useful new approach to screening for diabetes.