Hsa_circRNA_405498 and hsa_circRNA_100033 Serve as Potential Biomarkers for Differential Diagnosis of Type 1 Diabetes

CONTEXT

The role of circular RNAs (circRNAs) in type 1 diabetes (T1D) is largely unknown.

OBJECTIVE

We aimed to identify some circRNAs as differential diagnostic biomarkers for T1D to distinguish between patients with latent autoimmune diabetes in adults (LADA) and type 2 diabetes (T2D).

METHODS

The circRNA expression profiles were determined by Arraystar human circRNA microarray in T1D compared to controls (n = 6 each). The differentially expressed circRNAs were validated by real-time quantitative polymerase chain reaction using a validation cohort with 20 T1D and 20 controls. The diagnostic performances of the candidate circRNAs and the clinical parameters were assessed using the logistic least absolute shrinkage and selection operator (LASSO) regression model in a larger cohort with 457 individuals, including patients with T1D, T2D, and LADA, and controls.

RESULTS

We identified 110 differentially expressed circular transcripts (53 upregulated and 57 downregulated) in T1D patients compared with controls. Further analysis showed that the levels of hsa_circRNA_405498 and hsa_circRNA_100033 were significantly downregulated in T1D compared to controls (both P < .05). Moreover, the expression levels of these 2 circRNAs showed sequential downregulation from controls, patients with T2D, LADA, to T1D (P < .05). The area under the curve (AUC) of receiver operating characteristic plots in logistic LASSO regression model showed high diagnostic accuracy for combination model with the 2 circRNAs and some clinical parameters in distinguishing T1D from LADA (AUC = 0.915), T2D (AUC = 0.993), and controls (AUC = 0.992).

CONCLUSION

Our study demonstrated that hsa_circRNA_405498 and hsa_circRNA_100033 are promising novel differential diagnostic biomarkers for T1D.

Comparative Screening of the Liver Gene Expression Profiles from Type 1 and Type 2 Diabetes Rat Models

Experimental animal models of diabetes can be useful for identifying novel targets related to disease, for understanding its physiopathology, and for evaluating emerging antidiabetic treatments. This study aimed to characterize two rat diabetes models: HFD + STZ, a high-fat diet (60% fat) combined with streptozotocin administration (STZ, 35 mg/kg BW), and a model with a single STZ dose (65 mg/kg BW) in comparison with healthy rats. HFD + STZ- induced animals demonstrated a stable hyperglycemia range (350-450 mg/dL), whereas in the STZ-induced rats, we found glucose concentration values with a greater dispersion, ranging from 270 to 510 mg/dL. Moreover, in the HFD + STZ group, the AUC value of the insulin tolerance test (ITT) was found to be remarkably augmented by 6.2-fold higher than in healthy animals (33,687.0 ± 1705.7 mg/dL/min vs. 5469.0 ± 267.6, respectively), indicating insulin resistance (IR). In contrast, a more moderate AUC value was observed in the STZ group (19,059.0 ± 3037.4 mg/dL/min) resulting in a value 2.5-fold higher than the average exhibited by the control group. After microarray experiments on liver tissue from all animals, we analyzed genes exhibiting a fold change value in gene expression <-2 or >2 (p-value <0.05). We found 27,686 differentially expressed genes (DEG), identified the top 10 DEGs and detected 849 coding genes that exhibited opposite expression patterns between both diabetes models (491 upregulated genes in the STZ model and 358 upregulated genes in HFD + STZ animals). Finally, we performed an enrichment analysis of the 849 selected genes. Whereas in the STZ model we found cellular pathways related to lipid biosynthesis and metabolism, in the HFD + STZ model we identified pathways related to immunometabolism. Some phenotypic differences observed in the models could be explained by transcriptomic results; however, further studies are needed to corroborate these findings. Our data confirm that the STZ and the HFD + STZ models are reliable experimental models for human T1D and T2D, respectively. These results also provide insight into alterations in the expression of specific liver genes and could be utilized in future studies focusing on diabetes complications associated with impaired liver function.

CircRNA hsa_circ_0071336 is associated with type 2 diabetes through targeting the miR-93-5p/GLUT4 axis

Glucose transporter 4 (GLUT4) is a dominant regulator of whole-body glucose homeostasis. Accumulating evidence has shown that circular RNAs (circRNAs) play significant roles in the pathogenesis of disease. The aim of the present study was to identify the circRNA that can be used as a novel biomarker for type 2 diabetes (T2D) through regulating GLUT4. Based on previous microarray analysis comparing T2D cases and healthy controls, hsa_circ_0071336, which was predicted to be a regulator of GLUT4 by acting as a competitive endogenous RNAs (ceRNA) to sponge miR-93-5p, was selected for further validation. The clinical significance of circulating hsa_circ_0071336 was investigated in a large independent cohort. The results showed that circulating hsa_circ_0071336 was significantly downregulated in blood in T2D and had a high diagnostic accuracy for discriminating T2D and impaired fasting glucose (IFG) from healthy controls. Low expression of circ_0071336 was an independent predictor of T2D, IFG and insulin resistance. A luciferase reporter assay and western-blot analysis indicated that miR-93-5p was a direct target of hsa_circ_0071336, and miR-93-5p may negatively regulate the expression of GLUT4. The expression levels of hsa_circ_007136 were negatively related to miR-93-5p expression and positively correlated with the mRNA expression of GLUT4 in adipose tissues. In conclusion, hsa_circRNA_0071336 can be considered as a potential novel and stable biomarker for T2D and its early detection. hsa_circ_0071336 regulates the GLUT4 expression by sponging miR-93-5p and maybe involved in the pathogenesis of T2D. These findings may unveil new targets for the prevention, diagnosis and treatment of T2D.

Identification of Circulating hsa_circ_0063425 and hsa_circ_0056891 as Novel Biomarkers for Detection of Type 2 Diabetes

CONTEXT

Circular RNAs (circRNAs), which are involved in the development of diseases by regulating gene expression, have become promising novel biomarkers for diseases.

OBJECTIVE

The aim of the present study was to identify the circulating circRNA biomarkers for early detection of type 2 diabetes (T2D).

METHODS

The circRNA expression profiles were screened by microarray and compared between 5 new T2D cases and 5 healthy controls. The expression of candidate circRNAs that may be involved in the insulin phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway were validated by RT-qPCR in a second sample with 30 T2D cases and 30 controls. The association between circRNAs and T2D and their clinical significances were further assessed by logistic regression model, correlation analysis, and ROC curve in a large cohort comprising 313 subjects. The microRNA (miRNA) targets of circRNAs were verified by dual-luciferase reporter assay and RNA immunoprecipitation assay.

RESULTS

Low expressed circ_0063425 and hsa_circ_0056891 were independent predictors of T2D, impaired fasting glucose (IFG), and insulin resistance. The 2-circRNA panel had a high diagnostic accuracy for discriminating T2D and IFG from healthy controls, especially when body mass index was integrated. miR-19a-3p and miR-1-3p were identified as the miRNA targets of hsa_circ_0063425 and hsa_circ_0056891, respectively. Significant positive correlations were found between the expression levels of AKT and hsa_circ_0063425, PI3K and hsa_circ_0056891, in the total sample and subgroups stratified by glucose levels.

CONCLUSION

Downregulated hsa_circ_0063425 and hsa_circ_0056891 might contribute to the pathogenesis of T2D. They are valuable circulating biomarkers for early detection of T2D, which may be involved in regulation of PI3K/AKT signaling.

SP prevents T2DM complications by immunomodulation

Type 2 diabetic mellitus (T2DM) is characterized by systemic inflammation and insulin resistance due to obesity, and this leads to critical complications, including retinopathy and nephropathy. This study explored the therapeutic effect of substance-p (SP), a neuropeptide, on T2DM progression and its complications. To examine whether SP affects glucose metabolism, lipid metabolism, systemic inflammation, and retinopathy, Otsuka Long-Evans Tokushima Fatty rats (OLETF, 27 weeks old) with chronic inflammation, obesity, and impaired bone marrow stem cell pool was selected. SP was intravenously injected and its effect was evaluated at 2 and 4 weeks after the SP injection. OLETF had typical symptoms of T2DM, including obesity, chronic inflammation, and poor glycemic control. However, SP treatment inhibited the body-weight gain and reduced circulating levels of free fatty acid, cholesterol, and triglyceride, ameliorating the obese environment. SP could suppress inflammation and rejuvenate bone marrow stem cell in OLETF rats. SP-mediated metabolic/immunological change could resolve hyperglycemia and insulin resistance. Histopathological analysis confirmed that SP treatment alleviated the dysfunction of target tissue with insulin resistance. OLETF rats have retinal damage from 27 weeks of age, which was reliably aggravated at 31 weeks. However, SP treatment could restore the damaged retina, sustaining its structure similarly to that of non-diabetic rats. In conclusion, systemic application of SP is capable contribute to the inhibition of the progression of T2DM and diabetic retinopathy.

A millisecond micro-RNA separation technique by a hybrid structure of nanopillars and nanoslits

A millisecond micro-RNA separation of a mixture of total RNA and genomic DNA, extracted from cultured HeLa cells, was successfully achieved using a hybrid structure of nanopillars and nanoslits contained inside a microchannel. The nanopillars, 250-nm in diameter and 100-nm in height, were fabricated with a 750-nm space inside the nanoslits, which were 100-nm in height and 25-μm in width; the nanopillars were then applied as a new sieve matrix. This ultra-fast technique for the separation of miRNA can be an effective pretreatment for semiconductor nanopore DNA sequencing, which has an optimum reading speed of 1 base/ms to obtain effective signal-to-noise ratio and discriminate each base by ion or tunneling current during the passage of nucleic acids.

Intrauterine growth restriction modifies gene expression profiling in cord blood

BACKGROUND

Small-for-gestational-age (SGA) newborns are at an increased risk for perinatal morbidity and mortality and development of metabolic syndromes such as cardiovascular disease and type 2 diabetes mellitus (T2DM) in adulthood. The mechanism underlying this increased risk remains unclear. In this study, genetic modifications of cord blood were investigated to characterize fetal change in SGA newborns.

METHODS

Gene expression in cord blood cells was compared between 10 SGA newborns and 10 appropriate-for-gestational-age (AGA) newborns using microarray analysis. Pathway analysis was conducted using the Ingenuity Pathways Knowledge Base. To confirm the microarray analysis results, quantitative real-time polymerase chain reaction (RT-PCR) was performed for upregulated genes in SGA newborns.

RESULTS

In total, 775 upregulated and 936 downregulated probes were identified in SGA newborns and compared with those in AGA newborns. Of these probes, 1149 were annotated. Most of these genes have been implicated in the development of cardiovascular disease and T2DM. There was good agreement between the RT-PCR and microarray analyses results.

CONCLUSIONS

Expression of certain genes was modified in SGA newborns in the fetal period. These genes have been associated with metabolic syndrome. To clarify the association between modified gene expression in cord blood and individual vulnerability to metabolic syndrome in adulthood, these SGA newborns will be have long-term follow up for examination of genetic and postnatal environmental factors. Gene expression of cord blood can be a useful and non-invasive method of investigation of genetic alterations in the fetal period.

Integrative analysis of the transcriptome profiles observed in type 1, type 2 and gestational diabetes mellitus reveals the role of inflammation

BACKGROUND

Type 1 diabetes (T1D) is an autoimmune disease, while type 2 (T2D) and gestational diabetes (GDM) are considered metabolic disturbances. In a previous study evaluating the transcript profiling of peripheral mononuclear blood cells obtained from T1D, T2D and GDM patients we showed that the gene profile of T1D patients was closer to GDM than to T2D. To understand the influence of demographical, clinical, laboratory, pathogenetic and treatment features on the diabetes transcript profiling, we performed an analysis integrating these features with the gene expression profiles of the annotated genes included in databases containing information regarding GWAS and immune cell expression signatures.

METHODS

Samples from 56 (19 T1D, 20 T2D, and 17 GDM) patients were hybridized to whole genome one-color Agilent 4x44k microarrays. Non-informative genes were filtered by partitioning, and differentially expressed genes were obtained by rank product analysis. Functional analyses were carried out using the DAVID database, and module maps were constructed using the Genomica tool.

RESULTS

The functional analyses were able to discriminate between T1D and GDM patients based on genes involved in inflammation. Module maps of differentially expressed genes revealed that modulated genes: i) exhibited transcription profiles typical of macrophage and dendritic cells; ii) had been previously associated with diabetic complications by association and by meta-analysis studies, and iii) were influenced by disease duration, obesity, number of gestations, glucose serum levels and the use of medications, such as metformin.

CONCLUSION

This is the first module map study to show the influence of epidemiological, clinical, laboratory, immunopathogenic and treatment features on the transcription profiles of T1D, T2D and GDM patients.

Hepatic Monoacylglycerol O-acyltransferase 1 as a Promising Therapeutic Target for Steatosis, Obesity, and Type 2 Diabetes

Over the past decade, considerable advances have been made in the discovery of gene targets in metabolic diseases. However, in vivo studies based on molecular biological technologies such as the generation of knockout mice and the construction of short hairpin RNA vectors require considerable effort and time, which is a major limitation for in vivo functional analysis. Here, we introduce a liver-specific nonviral small interfering RNA (siRNA) delivery system into rapid and efficient characterization of hepatic gene targets in metabolic disease mice. The comparative transcriptome analysis in liver between KKAy diabetic and normal control mice demonstrated that the expression of monoacylglycerol O-acyltransferase 1 (Mogat1), an enzyme involved in triglyceride synthesis and storage, was highly elevated during the disease progression. The upregulation of Mogat1 expression in liver was also found in other genetic (db/db) and diet-induced obese mice. The silencing of hepatic Mogat1 via a liver-specific siRNA delivery system resulted in a dramatic improvement in blood glucose levels and hepatic steatosis as well as overweight with no apparent overall toxicities, indicating that hepatic Mogat1 is a promising therapeutic target for metabolic diseases. The integrated approach with transcriptomics and nonviral siRNA delivery system provides a blueprint for rapid drug discovery and development.

Nanomedicine for treatment of diabetes in an aging population: state-of-the-art and future developments

Nowadays diabetes, especially type 2 diabetes (which is strongly related to the Western diet and life-style), has developed worldwide into an epidemic disease. Nanomedicine aims to provide novel tools for diagnosis, therapy and point-of-care management of patients. Several nanotechnological approaches were developed to improve life quality for patients with insulin-dependent diabetes. They facilitate blood glucose management by non-invasive glucose measurement as well as insulin administration mainly by delivering the fragile protein as protected and targeted formulation via nasal or oral route. In the present review the oral or nasal insulin delivery by polymeric nanoparticles is discussed with focus on physiological change either related to the disease, diabetes or age-related metabolic variations influencing insulin release and bioavailability. One critical point is that new generations of targeted nanoparticle based drugs are developed and optimized for certain metabolic conditions. These conditions may change with age or disease. The influence of age-related factors such as immaturity in very young age, metabolic and physiologic changes in old age or insufficient animal models are still under-investigated not only in nanomedicine but also generally in pharmacology. Summarizing it can be noted that the bioavailability of insulin administered via routes others than subcutaneously is comparably low (max. 60%). Moreover factors like changed gut permeability as described for diabetes type 1 or other metabolic peculiarities such as insulin resistance in case of type 2 diabetes also play a role in affecting the development of novel nanoparticulated drug preparations and can be responsible for unsuccessful translation of promising animal results into human therapy. In future insulin nanoparticle development for diabetes must consider not only requirements imposed by the drug but also metabolic changes inflicted by disease or by age. Moreover new approaches are required for prevention of the disease.

Oligonucleotide microarray analysis of dietary-induced hyperlipidemia gene expression profiles in miniature pigs

Background

Hyperlipidemia animal models have been established, but complete gene expression profiles of the transition from normal lipid levels have not been obtained. Miniature pigs are useful model animals for gene expression studies on dietary-induced hyperlipidemia because they have a similar anatomy and digestive physiology to humans, and blood samples can be obtained from them repeatedly.

Methodology

Two typical dietary treatments were used for dietary-induced hyperlipidemia models, by using specific pathogen-free (SPF) Clawn miniature pigs. One was a high-fat and high-cholesterol diet (HFCD) and the other was a high-fat, high-cholesterol, and high-sucrose diet (HFCSD). Microarray analyses were conducted from whole blood samples during the dietary period and from white blood cells at the end of the dietary period to evaluate the transition of expression profiles of the two dietary models.

Principal Findings

Variations in whole blood gene expression intensity within the HFCD or the HFCSD group were in the same range as the controls provide with normal diet at all periods. This indicates uniformity of dietary-induced hyperlipidemia for our dietary protocols. Gene ontology- (GO) based functional analyses revealed that characteristics of the common changes between HFCD and HFCSD were involved in inflammatory responses and reproduction. The correlation coefficient between whole blood and white blood cell expression profiles at 27 weeks with the HFCSD diet was significantly lower than that of the control and HFCD diet groups. This may be due to the effects of RNA originating from the tissues and/or organs.

Conclusions

No statistically significant differences in fasting plasma lipids and glucose levels between the HFCD and HFCSD groups were observed. However, blood RNA analyses revealed different characteristics corresponding to the dietary protocols. In this study, whole blood RNA analyses proved to be a useful tool to evaluate transitions in dietary-induced hyperlipidemia gene expression profiles in miniature pigs.

Nanomedicine for treatment of diabetes in an aging population: state-of-the-art and future developments

Nowadays diabetes, especially type 2 diabetes (which is strongly related to the Western diet and life-style), has developed worldwide into an epidemic disease. Nanomedicine aims to provide novel tools for diagnosis, therapy and point-of-care management of patients. Several nanotechnological approaches were developed to improve life quality for patients with insulin-dependent diabetes. They facilitate blood glucose management by non-invasive glucose measurement as well as insulin administration mainly by delivering the fragile protein as protected and targeted formulation via nasal or oral route. In the present review the oral or nasal insulin delivery by polymeric nanoparticles is discussed with focus on physiological change either related to the disease, diabetes or age-related metabolic variations influencing insulin release and bioavailability. One critical point is that new generations of targeted nanoparticle based drugs are developed and optimized for certain metabolic conditions. These conditions may change with age or disease. The influence of age-related factors such as immaturity in very young age, metabolic and physiologic changes in old age or insufficient animal models are still under-investigated not only in nanomedicine but also generally in pharmacology. Summarizing it can be noted that the bioavailability of insulin administered via routes others than subcutaneously is comparably low (max. 60%). Moreover factors like changed gut permeability as described for diabetes type 1 or other metabolic peculiarities such as insulin resistance in case of type 2 diabetes also play a role in affecting the development of novel nanoparticulated drug preparations and can be responsible for unsuccessful translation of promising animal results into human therapy. In future insulin nanoparticle development for diabetes must consider not only requirements imposed by the drug but also metabolic changes inflicted by disease or by age. Moreover new approaches are required for prevention of the disease.

Transcriptomic profiles of peripheral white blood cells in type II diabetes and racial differences in expression profiles

Background

Along with obesity, physical inactivity, and family history of metabolic disorders, African American ethnicity is a risk factor for type 2 diabetes (T2D) in the United States. However, little is known about the differences in gene expression and transcriptomic profiles of blood in T2D between African Americans (AA) and Caucasians (CAU), and microarray analysis of peripheral white blood cells (WBCs) from these two ethnic groups will facilitate our understanding of the underlying molecular mechanism in T2D and identify genetic biomarkers responsible for the disparities.

Results

A whole human genome oligomicroarray of peripheral WBCs was performed on 144 samples obtained from 84 patients with T2D (44 AA and 40 CAU) and 60 healthy controls (28 AA and 32 CAU). The results showed that 30 genes had significant difference in expression between patients and controls (a fold change of <-1.4 or >1.4 with a P value <0.05). These known genes were mainly clustered in three functional categories: immune responses, lipid metabolism, and organismal injury/abnormaly. Transcriptomic analysis also showed that 574 genes were differentially expressed in AA diseased versus AA control, compared to 200 genes in CAU subjects. Pathway study revealed that "Communication between innate and adaptive immune cells"/"Primary immunodeficiency signaling" are significantly down-regulated in AA patients and "Interferon signaling"/"Complement System" are significantly down-regulated in CAU patients.

Conclusions

These newly identified genetic markers in WBCs provide valuable information about the pathophysiology of T2D and can be used for diagnosis and pharmaceutical drug design. Our results also found that AA and CAU patients with T2D express genes and pathways differently.

Transcriptional profiling to identify biomarkers of disease and drug response

The discovery, biological qualification and analytical validation of genomic biomarkers requires extensive collaborations between individuals with expertise in biology, statistics, bioinformatics, chemistry, clinical medicine, regulatory science and so on. For clinical utility, blood-borne biomarkers (e.g., mRNA and miRNA) of organ damage, drug toxicity and/or response would be preferred to those that are tissue based. Currently used biomarkers such as serum creatinine (indicating renal dysfunction) denote organ damage whether caused by disease, physical injury or drugs. Therefore, it is anticipated that studies of disease will discover biomarkers that can also be used to identify drug-induced injury and vice versa. This article describes transcriptomic blood-borne biomarkers that have been reported to be connected with disease and drug toxicity. Much more qualification and validation needs to be carried out before many of these biomarkers can prove useful. Discussed here are some of the lessons learned and roadblocks to success.