Genetic insights into repurposing statins for hyperthyroidism prevention: a drug-target Mendelian randomization study.

Background: Current therapeutic measures for thyroid dysfunction are limited and often accompanied by adverse effects. The use of lipid-lowering drugs like statins has recently been associated with lower thyroid eye diseases risk. Objective: To investigate the implications of genetically proxied lipid-lowering drugs on thyroid dysfunction. Methods: In this drug-target Mendelian randomization (MR) study, we utilized genetic variants within drug target genes associated with low-density lipoprotein (LDL) or triglyceride (TG), derived from a genome-wide association study (GWAS) meta-analysis (N ≤ 188,577), to simulate lifelong drug interventions. Genetic summary statistics for thyroid dysfunction outcomes were retrieved from GWAS datasets of Thyroid Omics Consortium (N ≤ 54,288) and UK Biobank (N = 484,598). Inverse-variance-weighted MR (IVW-MR) method was performed as primary analysis, followed by validation in colocalization analysis. A subsequent two-step MR analysis was conducted to identify biomarkers mediating the identified drug-outcome association. Results: In IVW-MR analysis, genetic mimicry of 3-hydroxy-3-methylglutarylcoenzyme reductase (HMGCR) inhibitors (e.g. statins) was significantly associated with lower risk of hyperthyroidism in two independent datasets (OR1, 0.417 per 1-mmol/L lower in LDL-C; 95% CI 0.262 to 0.664; P1 = 2.262 × 10-4; OR2 0.996; 95% CI 0.993-0.998; P2 = 0.002). Two-step MR analysis revealed eighteen biomarkers linked to genetic mimicry of HMGCR inhibition, and identified insulin-like growth factor 1 (IGF-1) levels mediating 2.108% of the negative causal relationship between HMGCR inhibition and hyperthyroidism. Conclusion: This study supports HMGCR inhibition as a promising therapeutic strategy for hyperthyroidism and suggests its underlying mechanisms may extend beyond lipid metabolism. Further investigations through laboratory studies and clinical trials are necessary to confirm and elucidate these findings.

Measurement of cumulative high-sensitivity C-reactive protein and monocyte to high-density lipoprotein ratio in the risk prediction of type 2 diabetes: a prospective cohort study.

BACKGROUND: Converging data have suggested that monocytic inflammation and C-reactive protein (CRP) are biologically intertwined processes and are involved in diabetogenesis. This study aimed to investigate the association between systemic inflammation assessed by joint cumulative high-sensitivity C-reactive protein (CumCRP) and monocyte to high-density lipoprotein ratio (CumMHR) and incident type 2 diabetes (T2D) and their predictive value for T2D in a general population. METHODS: A total of 40,813 nondiabetic participants from a prospective real-life cohort (Kailuan Study, China) were followed biennially from 2010/2011 until December 31, 2020. Multivariable Cox regression analyses were conducted to evaluate the adjusted hazard ratios (aHRs) of incident diabetes. RESULTS: During a median follow-up of 7.98 (IQR: 5.74-8.87) years, 4848 T2D cases developed. CumMHR and CumCRP were alone or jointly associated with incident T2D after adjusting for potential confounders. Elevated CumMHR levels significantly increased the risk of incident diabetes in each CumCRP strata (P-interaction: 0.0278). Participants with concomitant elevations in CumMHR and CumCRP levels had the highest risk (aHR: 1.71, 95% CI 1.52-1.91) compared to both in the low strata. Notably, the coexposure-associated T2D risk was modified by age, sex, hypertension, dyslipidemia, and prediabetes status. C-statistics increased from 0.7377 to 0.7417 when CumMHR and CumCRP were added into the multivariable-adjusted model, with a net reclassification improvement (%) of 12.39 (9.39-15.37) (P < 0.0001). CONCLUSIONS: Cumulative hsCRP and MHR were both independently and jointly associated with an increased risk of T2D and their addition to established risk factors should improve risk prediction and reclassification of diabetes.

Sclerotome-derived PDGF signaling functions as a niche cue responsible for primitive erythropoiesis.

Primitive erythropoiesis serves a vital role in embryonic development, generating primitive red blood cells responsible for transportation of oxygen throughout the body. Although diverse niche factors are known to function in definitive hematopoiesis, the microenvironment contributing to primitive hematopoiesis remains largely elusive. Here, we report that platelet-derived growth factor (PDGF) signaling is required for erythroid progenitor differentiation in zebrafish. Ablating pdgfαa (also known as pdgfaa) and pdgfαb (also known as pdgfab) or blocking PDGF signaling with an inhibitor impairs erythroid progenitor differentiation, thus resulting in a significant decrease in the number of erythrocytes. We reveal that pdgfαb is expressed in sclerotomal cells, and that its receptor genes, pdgfra and pdgfrb, are expressed in the adjacent erythroid progenitor cells. Sclerotome-specific overexpression of pdgfαb effectively restores primitive erythropoiesis in pdgfαa-/-;pdgfαb-/- mutant embryos. In addition, we have defined ERK1/2 signaling as a downstream pathway of PDGF signaling during embryonic erythropoiesis. Taken together, our findings indicate that PDGF signaling derived from sclerotome functions as a niche cue for primitive erythropoiesis.

Direct Differentiation of Human Embryonic Stem Cells to 3D Functional Hepatocyte-like Cells in Alginate Microencapsulation Sphere.

BACKGROUND: The lack of a stable source of hepatocytes is one of major limitations in hepatocyte transplantation and clinical applications of a bioartificial liver. Human embryonic stem cells (hESCs) with a high degree of self-renewal and totipotency are a potentially limitless source of a variety of cell lineages, including hepatocytes. Many techniques have been developed for effective differentiation of hESCs into functional hepatocyte-like cells. However, the application of hESC-derived hepatocyte-like cells (hESC-Heps) in the clinic has been constrained by the low yield of fully differentiated cells, small-scale culture, difficulties in harvesting, and immunologic graft rejection. To resolve these shortcomings, we developed a novel 3D differentiation system involving alginate-microencapsulated spheres to improve current hepatic differentiation, providing ready-to-use hESC-Heps. METHODS: In this study, we used alginate microencapsulation technology to differentiate human embryonic stem cells into hepatocyte-like cells (hESC-Heps). Hepatic markers of hESC-Heps were examined by qPCR and Western blotting, and hepatic functions of hESC-Heps were evaluated by indocyanine-green uptake and release, and ammonia removal. RESULTS: The maturity and hepatic functions of the hESC-Heps derived from this 3D system were better than those derived from 2D culture. Hepatocyte-enriched genes, such as HNF4α, AFP, and ALB, were expressed at higher levels in 3D hESC-Heps than in 2D hESC-Heps. 3D hESC-Heps could metabolize indocyanine green and had better capacity to scavenge ammonia. In addition, the 3D sodium alginate hydrogel microspheres could block viral entry into the microspheres, and thus protect hESC-Heps in 3D microspheres from viral infection. CONCLUSION: We developed a novel 3D differentiation system for differentiating hESCs into hepatocyte-like cells by using alginate microcapsules.

The association of uric acid with the development of thyroid nodules: a retrospective cohort study.

BACKGROUND: Uric acid was found to have a positive correlation with thyroid nodules in the cross-sectional studies recently. We aimed to conduct a retrospective cohort study to investigate whether uric acid is a risk factor for the development of thyroid nodules. METHODS: We reviewed the data of individuals who attended the medical check-ups in our hospital from 2010 to 2019. A total of 6587 adults without thyroid nodules at baseline were enrolled in this study. Logistic regression with or without restricted cubic spline function was used to investigate the non-linear or linear association between uric acid and thyroid nodules, respectively. RESULTS: Baseline characteristics showed that subjects mainly consisted of the healthy, young population. After fully adjusting for the potential confounders, such as age, sex, metabolic and inflammatory indicators, hepatic and renal function, a logistic restricted cubic spline regression model suggested that uric acid had a significant association (P = 0.028) with the development of thyroid nodules, but the association was not non-linear (P = 0.516). The results indicate that the association between them is linear, which was demonstrated by a logistic regression model, in which the odds ratio of uric acid per 100 mmol/L was 1.137 (P = 0.004). Age, sex, diastolic blood pressure, fasting blood sugar, and blood monocyte were found to be risk factors for thyroid nodules as well. CONCLUSION: Uric acid is an independent risk factor for the formation of thyroid nodules. This finding warrants attention to this risk factor in apparently healthy adults.

Membrane tethering of CreER decreases uninduced cell labeling and cytotoxicity while maintaining recombination efficiency.

Genetic lineage tracing is indispensable to unraveling the origin, fate, and plasticity of cells. However, the intrinsic leakiness in the CreER-loxP system raises concerns on data interpretation. Here, we reported the generation of a novel dual inducible CreER-loxP system with superior labeling characteristics. This two-component system consists of membrane localized CreER (mCreER: CD8α-FRB-CS-CreER) and TEV protease (mTEVp: CD8α-FKBP-TEVp), which are fusion proteins incorporated with the chemically induced dimerization machinery. Rapamycin and tamoxifen induce sequential dimerization of FKBP and FRB, cleavage of CreER from the membrane, and translocation into the nucleus. The labeling leakiness in Ad293 cells reduced dramatically from more than 70% to less than 5%. This tight labeling feature depends largely on the association of mCreER with HSP90, which conceals the TEV protease cutting site between FRB and CreER and thus preventing uninduced cleavage of the membrane-tethering CreER. Membrane-bound CreER also diminished significantly cytotoxicity. Our studies showed mCreER under the control of the rat insulin promoter increased labeling specificity in MIN6 islet beta-cells. Viability and insulin secretion of MIN6 cells remained intact. Our results demonstrate that this novel system can provide more stringent temporal and spatial control of gene expression and will be useful in cell fate probing.

Obesity and Overweight Are Independently Associated with Greater Survival in Critically Ill Diabetic Patients: A Retrospective Cohort Study.

BACKGROUND: The relationship between obesity and the outcomes of critically ill diabetic patients is not completely clear. We aimed to assess the effects of obesity and overweight on the outcomes among diabetic patients in the intensive care unit (ICU). METHODS: Critically ill diabetic patients in the ICU were classified into three groups according to their body mass index. The primary outcomes were 30-day and 90-day mortality. ICU and hospital length of stay (LOS) and incidence and duration of mechanical ventilation were also assessed. Cox regression models were developed to evaluate the relationship between obesity and overweight and mortality. RESULTS: A total of 6108 eligible patients were included. The 30-day and 90-day mortality in the normal weight group were approximately 1.8 times and 1.5 times higher than in the obesity group and overweight group, respectively (P < 0.001, respectively). Meanwhile, the ICU (median (IQ): 2.9 (1.7, 5.3) vs. 2.7 (1.6, 4.8) vs. 2.8 (1.8, 5.0)) and hospital (median (IQ): 8.3 (5.4, 14.0) vs. 7.9 (5.1, 13.0) vs. 8.3 (5.3, 13.6)) LOS in the obesity group and overweight group were not longer than in the normal weight group. Compared with normal weight patients, obese patients had significantly higher incidence of mechanical ventilation (58.8% vs. 64.7%, P < 0.001) but no longer ventilation duration (median (IQ): 19.3 (7.0, 73.1) vs. 19.0 (6.0, 93.7), P = 1). Multivariate Cox regression showed that obese and overweight patients had lower 30-day (HR (95% CI): 0.62 (0.51, 0.75); 0.76 (0.62, 0.92), respectively) and 90-day (HR (95% CI): 0.60 (0.51, 0.70); 0.79 (0.67, 0.93), respectively) mortality risks than normal weight patients. CONCLUSIONS: Obesity and overweight were independently associated with greater survival in critically ill diabetic patients, without increasing the ICU and hospital LOS. Large multicenter prospective studies are needed to confirm our findings and the underlying mechanisms warrant further investigation.

Doxycycline in Extremely Low Dose Improves Glycemic Control and Islet Morphology in Mice Fed a High-Fat Diet.

PURPOSE: Chronic low-grade inflammation is detected in obese and diabetic individuals. Tetracyclines, used as antibiotics for years, have been demonstrated to have diverse non-bactericidal effects, including anti-tumor and anti-inflammatory activities. This study aimed to investigate whether doxycycline at sub-antimicrobial concentrations could improve glycemic control in mice fed a high-fat diet, through its anti-inflammatory activities. METHODS: C57BL/6J mice were fed with a high-fat diet to induce diabetic and obese conditions. Three sub-antimicrobial dosages of doxycycline (200, 20, and 2 µg/mL) were added to drinking water for 23 weeks during the housing phase. RESULTS: Doxycycline at 200 µg/mL tended to increase body weight, islet mass, and the percentage of large islets (diameter >350 µm). At 20 µg/mL, doxycycline significantly improved glucose tolerance and decreased fasting blood glucose. At 2 µg/mL, doxycycline increased the percentage of small islets (diameter <80 µm). Serum C-reactive protein and lipopolysaccharide levels significantly decreased while the beta-cell ratio increased in all doxycycline-administered mice. CONCLUSION: Our results suggest that doxycycline, even at an extremely low dose, could improve glycemic control and islet morphology via its anti-inflammatory activities.

Effectiveness and safety of human amnion/chorion membrane therapy for diabetic foot ulcers: An updated meta-analysis of randomized clinical trials.

Human amnion/chorion membrane therapy has shown advantages in the management of diabetic foot ulcers and its effectiveness has been evaluated in the systematic reviews and meta-analyses. However, the number of patients included in the previous literatures was small and the safety profile of human amnion/chorion membrane therapy was not concerned. Therefore, we conducted an updated meta-analysis to better understand the effectiveness and safety of human amnion/chorion membrane therapy for diabetic foot ulcers. The PubMed, Embase, Cochrane Library, and ClinicalTrial.gov databases were searched for any randomized clinical trials comparing human amnion/chorion membrane therapy and standard therapy in the treatment of diabetic foot ulcers. Ulcer healing rate was considered as the primary outcome and the secondary outcomes mainly included mean time to ulcer healing and adverse events. Nine RCTs with 541 patients were included. Compared with merely standard therapy, human amnion/chorion membrane therapy plus standard therapy improved the ulcer healing rates at 6 weeks (RR = 3.50, 95% CI: 2.35-5.21), 12 weeks (RR = 2.09, 95% CI: 1.53-2.85) and 16 weeks (RR = 1.70, 95% CI: 1.25-2.30), and also shortened the healing time (MD = -4.58, 95% CI: -5.70 to -3.46). Meanwhile, no significant difference was observed in the number of patients with adverse events (RR = 0.56, 95% CI: 0.31-1.03) between two groups. This meta-analysis suggests that human amnion/chorion membrane therapy as an adjuvant treatment could promote the healing of diabetic foot ulcers and has a safety profile. More evidence from large high-quality randomized clinical trials with long follow-up duration are in urgent need to further confirm our findings.

The Effect of Inflammation on the Formation of Thyroid Nodules.

BACKGROUND: Some studies have demonstrated that inflammation is highly associated with the prevalence of thyroid nodules (TNs). However, more confounders, such as metabolic diseases, should be adjusted. METHODS: A clinical study collecting 2722 subjects was conducted to confirm the association between inflammation and TNs. The underlying mechanism was investigated in combination with bioinformatics analysis. RESULTS: In the clinical study, propensity score matching was used to match metabolic parameters and other confounders, and it is observed that subjects with high inflammation had a higher prevalence of TNs and thyroid-stimulating hormone (TSH) than those with low inflammation. After further matching TNs, it is found that inflammation was positively associated with TSH, which was also demonstrated in a population without TNs. In bioinformatics study, inflammation did not promote TNs formation directly. Instead, it inhibited the synthesis of thyroid hormone, which might be the cause of the elevated TSH coexisting with inflammation. CONCLUSION: Inflammation promotes the development of TNs disease, probably due to its indirect effect through inhibiting the synthesis of thyroid hormone, which results in the elevation of TSH.

Plasma membrane vesicles of human umbilical cord mesenchymal stem cells ameliorate acetaminophen-induced damage in HepG2 cells: a novel stem cell therapy.

BACKGROUND: Acetaminophen (APAP) overdose is the common cause of acute liver failure (ALF) due to the oxidative damage of multiple cellular components. This study aimed to investigate whether plasma membrane vesicles (PMVs) from human umbilical cord mesenchymal stem cells (hUCMSCs) could be exploited as a novel stem cell therapy for APAP-induced liver injury. METHODS: PMVs from hUCMSCs were prepared with an improved procedure including a chemical enucleation step followed by a mechanical extrusion. PMVs of hUCMSCs were characterized and supplemented to hepatocyte cultures. Rescue of APAP-induced hepatocyte damage was evaluated. RESULTS: The hUCMSCs displayed typical fibroblastic morphology and multipotency when cultivated under adipogenic, osteogenic, or chondrogenic conditions. PMVs of hUCMSCs maintained the stem cell phenotype, including the presence of CD13, CD29, CD44, CD73, and HLA-ABC, but the absence of CD45, CD117, CD31, CD34, and HLA-DR on the plasma membrane surface. RT-PCR and transcriptomic analyses showed that PMVs were similar to hUCMSCs in terms of mRNA profile, including the expression of stemness genes GATA4/5/6, Nanog, and Oct1/2/4. GO term analysis showed that the most prominent reduced transcripts in PMVs belong to integral membrane components, extracellular vesicular exosome, and extracellular matrix. Immunofluorescence labeling/staining and confocal microscopy assays showed that PMVs enclosed cellular organelles, including mitochondria, lysosomes, proteasomes, and endoplasmic reticula. Incorporation of the fusogenic VSV-G viral membrane glycoprotein stimulated the endosomal release of PMV contents into the cytoplasm. Further, the addition of PMVs and a mitochondrial-targeted antioxidant Mito-Tempo into cultures of APAP-treated HepG2 cells resulted in reduced cell death, enhanced viability, and increased mitochondrial membrane potential. Lastly, this study demonstrated that the redox state and activities of aminotransferases were restored in APAP-treated HepG2 cells. CONCLUSIONS: The results suggest that PMVs from hUCMSCs could be used as a novel stem cell therapy for the treatment of APAP-induced liver injury.

The Efficacy and Safety of Acellular Matrix Therapy for Diabetic Foot Ulcers: A Meta-Analysis of Randomized Clinical Trials.

BACKGROUND: Acellular matrix (AM) therapy has shown promise in the treatment of diabetic foot ulcers (DFUs) in several studies. The clinical effects of AM therapy were not well established. Therefore, we conducted a meta-analysis of randomized clinical trials (RCTs) to examine the efficacy and safety of AM therapy for patients with DFUs. METHODS: A literature search of 5 databases was performed to identify RCTs comparing AM therapy to standard therapy (ST) in patients with DFUs. The primary outcome was the complete healing rate and the secondary outcomes mainly included time to complete healing and adverse events. RESULTS: Nine RCTs involving 897 patients were included. Compared with ST group, patients allocated to AM group had a higher complete healing rate both at 12 weeks (risk ratio (RR) = 1.73, 95% confidence interval (CI): 1.31 to 2.30) and 16 weeks (RR = 1.56, 95% CI: 1.28 to 1.91), a shorter time to complete healing (mean difference (MD) = -2.41; 95% CI: -3.49 to -1.32), and fewer adverse events (RR = 0.64, 95% CI: 0.44 to 0.93). CONCLUSION: The present study suggests that AM therapy as an adjuvant treatment could further promote the healing of full-thickness, noninfected, and nonischemia DFUs. AM therapy also has a safety profile. More large well-designed randomized clinical trials with long follow-up duration are needed to further explore the efficacy and safety of AM therapy for DFUs.

Classification of Thyroid Nodules with Stacked Denoising Sparse Autoencoder.

PURPOSE: Several commercial tests have been used for the classification of indeterminate thyroid nodules in cytology. However, the geographic inconvenience and high cost confine their widespread use. This study aims to develop a classifier for conveniently clinical utility. METHODS: Gene expression data of thyroid nodule tissues were collected from three public databases. Immune-related genes were used to construct the classifier with stacked denoising sparse autoencoder. RESULTS: The classifier performed well in discriminating malignant and benign thyroid nodules, with an area under the curve of 0.785 [0.638-0.931], accuracy of 92.9% [92.7-93.0%], sensitivity of 98.6% [95.9-101.3%], specificity of 58.3% [30.4-86.2%], positive likelihood ratio of 2.367 [1.211-4.625], and negative likelihood ratio of 0.024 [0.003-0.177]. In the cancer prevalence range of 20-40% for indeterminate thyroid nodules in cytology, the range of negative predictive value of this classifier was 37-61%, and the range of positive predictive value was 98-99%. CONCLUSION: The classifier developed in this study has the superb discriminative ability for thyroid nodules. However, it needs validation in cytologically indeterminate thyroid nodules before clinical use.

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.

An improved cellular enucleation method with extracellular matrix and colchicine facilitates the study of nucleocytoplasmic interaction.

Enucleated mammalian cells (cytoplasts) have been widely used for studying differential roles of the cytoplasm and nucleus in various cellular processes. Here, we reported an improved enucleation protocol, in which cells were seeded in extracellular matrix (ECM)-coated 24-wells and spun at 4600 g and 35 °C for 60 min in the presence of cytochalasin B and colchicine. When glass-bottom wells were used, cellular structures and organelles in cytoplasts could be examined directly by confocal microscopy. Nuclear envelope rupture did not occur probably due to mild centrifugation conditions used in this study. Addition of paclitaxel or doxorubicin completely blocked proliferation of residual nucleated cells; however, to our surprise, paclitaxel dramatically prolonged the survival of cytoplasts. Results from Annexin V and Propidium Iodide staining showed that cytoplasts died predominantly by apoptosis, which was partially inhibited by ECM and further by paclitaxel. Mitochondria were mostly rod-shaped and formed a connected network in paclitaxel-treated cytoplasts, indicating lack of fusion and fission dynamics. Moreover, paclitaxel increased mitochondrial membrane potential, suggesting that perturbation of mitochondria might be critical to the survival of cytoplasts. In conclusion, we had established an efficient and fast procedure for enucleation of adherent animal cells, which could facilitate the investigation of nucleocytoplasmic interaction.

Targeted deletion of Insm2 in mice result in reduced insulin secretion and glucose intolerance.

BACKGROUND: Neurogenin3 (Ngn3) and neurogenic differentiation 1 (NeuroD1), two crucial transcriptional factors involved in human diabetes (OMIM: 601724) and islet development, have been previously found to directly target to the E-boxes of the insulinoma-associated 2 (Insm2) gene promoter, thereby activating the expression of Insm2 in insulin-secretion cells. However, little is known about the function of Insm2 in pancreatic islets and glucose metabolisms. METHODS: Homozygous Insm2-/- mice were generated by using the CRISPR-Cas9 method. Glucose-stimulated insulin secretion and islet morphology were analyzed by ELISA and immunostainings. Expression levels of Insm2-associated molecules were measured using quantitative RT-PCR and Western blots. RESULTS: Fasting blood glucose levels of Insm2-/- mice were higher than wild-type counterparts. Insm2-/- mice also showed reduction in glucose tolerance and insulin/C-peptide levels when compared to the wild-type mice. RT-PCR and Western blot analysis revealed that expression of Insm1 was significantly increased in Insm2-/- mice, suggesting a compensatory response of the homolog gene Insm1. Similarly, transcriptional levels of Ngn3 and NeuroD1 were also increased in Insm2-/- mice. Moreover, Insm2-/- female mice showed a significantly decreased reproductive capacity. CONCLUSIONS: Our findings suggest that Insm2 is important in glucose-stimulated insulin secretion and is involved in the development pathway of neuroendocrine tissues which are regulated by the transcription factors Ngn3, NeuroD1 and Insm1.

Nicotinic Acid Receptor GPR109A Exerts Anti-Inflammatory Effects Through Inhibiting the Akt/mTOR Signaling Pathway in MIN6 Pancreatic ß cells.

OBJECTIVES: We found that activation of the nicotinic acid receptor GPR109A, expressed by the MIN6 murine pancreatic ß cell line, inhibits nitric oxide accumulation induced by IFN-γ and TNF-α, implicating an anti-inflammatory effect of GPR109A in MIN6 cells. Nevertheless, the mechanism of its anti-inflammatory effect is still unknown. In this study, we used palmitic acid to stimulate MIN6 cells to induce inflammatory cytokine production and explored the mechanism by which GPR109A exerts anti-inflammatory effects. MATERIALS AND METHODS: RT-PCR and immunocytochemical staining were used to detect the expression of GPR109A in MIN6 cells. Western blotting was used to detect the activation of the Akt/mTOR signaling pathway and expression of the inflammatory cytokine INF-γ, in MIN6 cells, following treatments with palmitic acid and palmitic acid+nicotinic acid, or with different concentrations of nicotinic acid and 3-hydroxybutyrate. RESULTS: In MIN6 cells, GPR109A transcripts and protein are expressed and GPR109A protein is mainly located in the cell membrane and cytoplasm. Palmitic acid enhanced the phosphorylation of Akt and p70S6K and elevated the expression of IFN-γ. Co-treatment with nicotinic acid, which is an agonist of GPR109A, inhibited the palmitic acid-induced phosphorylation of Akt, mTOR, and p70S6K, as well as the expression of IFN-γ. CONCLUSIONS: GPR109A may inhibit inflammatory cytokine production, induced by palmitic acid, by MIN6 cells possibly via inhibiting the Akt/mTOR signaling pathway.

Low dose doxycycline decreases systemic inflammation and improves glycemic control, lipid profiles, and islet morphology and function in db/db mice.

The aim of this study was to determine whether low dose doxycycline as an anti-inflammatory agent could improve glucose metabolism in diabetic animals. Therefore, doxycycline was supplemented in drinking water to 6-week-old male db/db mice for 10 weeks. Doxycycline reduced perirenal/epididymal fat, Lee's index, and liver cholesterol. Blood HDL-cholesterol increased, but total cholesterol and aspartate transaminase decreased. Glucose and insulin tolerances were improved, accompanying with reduced fasting blood glucose, insulin, HOMA-IR and advanced glycation end products. Islet number, ß-cell percentage and mass increased, while islet size decreased. Consistently, less apoptosis but more ß-cell proliferation were found in islets of treated mice. Freshly isolated islets from treated mice showed higher insulin content and enhanced glucose stimulated insulin secretion (GSIS). In addition, purified islets of Balb/c mice showed increased GSIS after cultivation in vitro with doxycycline, but not with chloramphenicol and levofloxacin. Inflammation markers, including lipopolysaccharides (LPS) and C-reactive protein (CRP) in serum as well as CD68-positive cells in treated islets, decreased significantly. Finally, LPS stimulated the production of inflammatory factors but inhibited GSIS of MIN6 cells; however, the effects were completely reversed by doxycycline. The results support further study of possible long-term usage of sub-antimicrobial doxycycline in diabetic patients.

The Effect of Metformin on the Expression of GPR109A, NF-κB and IL-1ß in Peripheral Blood Leukocytes from Patients with Type 2 Diabetes Mellitus.

OBJECTIVES: Type 2 Diabetes Mellitus (T2DM), which often accompanies dyslipidemia, is considered an inflammatory disease. GPR109A, as a niacin receptor, is up-regulated under high glucose concentration. Activation of GPR109A reduces GSIS and exerts anti-inflammatory effects by regulating NF-κB/IL-1ß signaling. Metformin improves hyperglycemia, increases insulin sensitivity and attenuates the activation of the NF-κB pathway in T2DM. We aimed to examine whether metformin plays beneficial effects in T2DM by regulating the GPR109A signaling. METHODS: 117 T2DM patients were involved in this study and divided into two groups, the control group (without metformin) and the Metformin (Met) group (orally given metformin, 500mg-2000mg/d). Peripheral blood samples were collected from all the patients for testing PBL counts, biochemical data, and C peptide. Total RNA was isolated from PBLs. RT-PCR and immunocytochemistry were used to examine the expression of GPR109A, NF-κB and IL-1ß in PBLs. RESULTS: FPG, HbA1c and LDL levels were lower and 2hr C peptide was higher in the Met group than in the control group (P<0.05). RT-PCR showed that mRNA levels of GPR109A, NF-κB and IL-1ß were lower in the Met group than in the control group (P<0.05). Correlation analysis showed that there was a positive correlation between GPR109A and IL-1ß (p<0.01, r=0.425) in the control group, GPR109A and IL-1ß (p<0.05, r=0.256), GPR109A, and NF-κB (p<0.05,r=0.295) in the Met group. Immunocytochemistry showed that the GPR109A and NF-κB proteins were localized in the nucleus and cytoplasm of PBLs; however, there were no significant differences in the protein expression between the two groups. CONCLUSIONS: The results suggest that Met may reduce GPR109A expression in PBLs of T2DM patients by suppressing NF-κB/IL-1ß signaling. Up-regulated expression of GPR109A may be an inflammatory consequence and the improvement of inflammation may down-regulate the expression of GPR109A in T2DM.

Preparation of Plasma Membrane Vesicles from Bone Marrow Mesenchymal Stem Cells for Potential Cytoplasm Replacement Therapy.

We have previously reported on the generation of plasma membrane vesicles (PMVs) through the mechanical extrusion of mammalian cells. The fusion of PMVs with mitochondrial deficient Rho0 cells restored mitotic activity under normal culture conditions. Atherosclerosis, type 2 diabetes, Alzheimer's disease, and cancer are age-related diseases that have been reported to be associated with multiple mechanical and functional defects in the cytosol and organelles of a variety of cell types. Bone marrow mesenchymal stem cells (BMSCs) represent a unique cell population from the bone marrow that possess self-renewal capabilities while maintaining their multipotency. The supplementation of senescence cells with young cytoplasm from autologous BMSCs via the fusion of PMVs provides a promising approach to ameliorate or even reverse age-associated phenotypes. This protocol describes how to prepare PMVs from BMSCs via extrusion through a polycarbonate membrane with 3 µm pores, determine the existence of mitochondria and examine the maintenance of membrane potential within PMVs using a confocal microscope, concentrate PMVs by centrifugation, and carry out the in vivo injection of PMVs into the gastrocnemius muscle of mice.