Molecular Determination of mirRNA-126 rs4636297, Phosphoinositide-3-Kinase Regulatory Subunit 1-Gene Variability rs7713645, rs706713 (Tyr73Tyr), rs3730089 (Met326Ile) and Their Association with Susceptibility to T2D

Role of antidiabetic agents in type 2 diabetes patients with chronic kidney disease

Insulin resistance is a condition in which the target tissues have a decreased response to insulin signaling, resulting in glucose uptake defect, and an increased blood sugar level. Pancreatic beta cells thus enhance insulin production to compensate. This situation may cause further beta cell dysfunction and failure, which can lead diabetes mellitus (DM). Insulin resistance is thus an important cause of the development of type 2 DM. Insulin resistance has also been found to have a strong relationship with cardiovascular disease and is common in chronic kidney disease (CKD) patients. The mechanisms of insulin resistance in CKD are complex and multifactorial. They include physical inactivity, inflammation and oxidative stress, metabolic acidosis, vitamin D deficiency, adipose tissue dysfunction, uremic toxins, and renin-angiotensin-aldosterone system activation. Currently, available anti-diabetic agents, such as biguanides, sulfonylureas, thiazolidinediones, alfa-glucosidase inhibitors, glucagon-like peptide-1-based agents, and sodium-glucose co-transporter-2 inhibitors, have different effects on insulin resistance. In this short review, we describe the potential mechanisms of insulin resistance in CKD patients. We also review the interaction of currently available anti-diabetic medications with insulin resistance.

Identification and Characterization of Novel Mutations in Chronic Kidney Disease (CKD) and Autosomal Dominant Polycystic Kidney Disease (ADPKD) in Saudi Subjects by Whole-Exome Sequencing

Background: Autosomal dominant polycystic kidney disease (ADPKD) is a condition usually caused by a single gene mutation and manifested by both renal and extrarenal features, eventually leading to end-stage renal disease (ESRD) by the median age of 60 years worldwide. Approximately 89% of ADPKD patients had either PKD1 or PKD2 gene mutations. The majority (85%) of the mutations are in the PKD1 gene, especially in the context of family history. Objectives: This study investigated the genetic basis and the undiscovered genes that are involved in ADPKD development among the Saudi population. Materials and Methods: In this study, 11 patients with chronic kidney disease were enrolled. The diagnosis of ADPKD was based on history and diagnostic images: CT images include enlargement of renal outlines, renal echogenicity, and presence of multiple renal cysts with dilated collecting ducts, loss of corticomedullary differentiation, and changes in GFR and serum creatinine levels. Next-generation whole-exome sequencing was conducted using the Ion Torrent PGM platform. Results: Of the 11 Saudi patients diagnosed with chronic kidney disease (CKD) and ADPKD, the most common heterozygote nonsynonymous variant in the PKD1 gene was exon15: (c.4264G > A). Two missense mutations were identified with a PKD1 (c.1758A > C and c.9774T > G), and one patient had a PKD2 mutation (c.1445T > G). Three detected variants were novel, identified at PKD1 (c.1758A > C), PKD2L2 (c.1364A > T), and TSC2 (deletion of a’a at the 3’UTR, R1680C) genes. Other variants in PKD1L1 (c.3813_381 4delinsTG) and PKD1L2 (c.404C > T) were also detected. The median age of end-stage renal disease for ADPK patients in Saudi Arabia was 30 years. Conclusion: This study reported a common variant in the PKD1 gene in Saudi patients with typical ADPKD. We also reported (to our knowledge) for the first time two novel missense variants in PKD1 and PKD2L2 genes and one indel mutation at the 3’UTR of the TSC2 gene. This study establishes that the reported mutations in the affected genes resulted in ADPKD development in the Saudi population by a median age of 30. Nevertheless, future protein−protein interaction studies to investigate the influence of these mutations on PKD1 and PKD2 functions are required. Furthermore, large-scale population-based studies to verify these findings are recommended.

Genetic Determinants of Cardiovascular Disease: The Endothelial Nitric Oxide Synthase 3 (eNOS3), Krüppel-Like Factor-14 (KLF-14), Methylenetetrahydrofolate Reductase (MTHFR), MiRNAs27a and Their Association with the Predisposition and Susceptibility to Coronary Artery Disease

Coronary artery disease (CAD) is an important cause of death worldwide. CAD is caused by genetic and other factors including hypertension, hyperlipidemia, obesity, stress, unhealthy diet, physical inactively, smoking and Type 2 diabetes (T2D). The genome wide association studies (GWASs) have revealed the association of many loci with risk to diseases such as cancers, T2D and CAD. Nitric oxide (NO) is a potent vasodilator and is required for normal vascular health. It is produced in the endothelial cells in a reaction catalyzed by the endothelial NO synthase (eNOS). Methylenetetrahydrofolate reductase (MTHFR) is a very important enzyme involved in metabolism of folate and homocysteine, and its reduced function leads to cardiovascular disease. The Krüppel-like factor-14 (KLF-14) is an important transcriptional regulator that has been implicated in metabolic syndrome. MicroRNA (MiRNAs) are short non-coding RNAs that regulate the gene expression of proteins involved in important physiological processes including cell cycle and metabolism. In the present study, we have investigated the potential impact of germline pathogenic variants of endothelial eNOS, KLF-14, MTHFR, MiRNA-27a and their association with risk to CAD in the Saudi population. Methods: Amplification Refractory Mutation System (ARMS) PCR was used to detect MTHFR, KLF-14, miRNA-27a and eNOS3 genotyping in CAD patients and healthy controls. About 125 CAD cases and 125 controls were enrolled in this study and statistical associations were calculated including p-value, risk ratio (RR), and odds ratio (OD). Results: There were statistically significant differences (p < 0.05) in genotype distributions of MTHFR 677 C>T, KLF-14 rs972283 G>A, miRNAs27a rs895819 A>G and eNOS3 rs1799983 G>T between CAD patients and controls. In addition, our results indicated that the MTHFR-TT genotype was associated with increased CAD susceptibility with an OR 2.75 (95%) and p < 0.049, and the KLF14-AA genotype was also associated with increased CAD susceptibility with an OR of 2.24 (95%) and p < 0.024. Moreover, the miRNAs27a-GG genotype protects from CAD risk with an OR = 0.31 (0.016), p = 0.016. Our results also indicated that eNOS3 -GT genotype is associated with CAD susceptibility with an OR = 2.65, and p < 0.0003. Conclusion: The MTHFR 677C>T, KLF14 rs972283 G>A, miRNAs27a A>G, and eNOS3 rs1799983 G>T genotypes were associated with CAD susceptibility (p < 0.05). These findings require verification in future large-scale population based studies before these loci are used for the prediction and identification of individuals at risk to CAD. Weight control, physical activity, and smoking cessation are very influential recommendations given by clinicians to the at risk individuals to reduce or delay the development of CAD.

Molecular Determination of Vascular Endothelial Growth Factor, miRNA-423 Gene Abnormalities by Utilizing ARMS-PCR and Their Association with Fetal Hemoglobin Expression in the Patients with Sickle Cell Disease

Recent studies have indicated that microRNA and VEGF are considered to be genetic modifiers and are associated with elevated levels of fetal haemoglobin HbF, and thus they reduce the clinical impact of sickle haemoglobin (HbS) patients. This cross-sectional study was performed on clinical confirmed subjects of SCD cases. miR-423-rs6505162 C>T and VEGF-2578 C>A genotyping was conducted by ARMS-PCR in SCD and healthy controls. A strong clinical significance was reported while comparing the association of miR-423 C>T genotypes between SCD patients and controls (p = 0.031). The microRNA-423 AA genotype was associated with an increased severity of SCD in codominant model with odd ratio (OR = 2.36, 95% CI, (1.15–4.84), p = 0.018) and similarly a significant association was observed in recessive inheritance model for microRNA-423 AA vs (CC+CA) genotypes (OR = 2.19, 95% CI, (1.32–3.62), p < 0.002). The A allele was associated with SCD severity (OR = 1.57, 95% CI, (1.13–2.19), p < 0.007). The distribution of VEGF-2578 C>A genotypes between SCD patients and healthy controls was significant (p < 0.013). Our results indicated that in the codominant model, the VEGF-2578-CA genotype was strongly associated with increased SCD severity with OR = 2.56, 95% CI, (1.36–4.82), p < 0.003. The higher expression of HbA1 (65.9%), HbA2 (4.40%), was reported in SCD patients carrying miR-423-AA genotype than miR-423 CA genotype in SCD patients carrying miR-423 CA genotype HbA1 (59.98%), HbA2 (3.74%) whereas SCD patients carrying miR-423 CA genotype has higher expression of HbF (0.98%) and HbS (38.1%) than in the patients carrying AA genotype HbF (0.60%), HbS (36.1%). ARMS-PCR has been proven to be rapid, inexpensive and is highly applicable to gene mutation screening in laboratories and clinical practices. This research highlights the significance of elucidating genetic determinants that play roles in the amelioration of the HbF levels that is used as an indicator of severity of clinical complications of the monogenic disease. Further well-designed studies with larger sample sizes are necessary to confirm our findings.

Clinical Implications of Krüpple-like Transcription Factor KLF-14 and Certain Micro-RNA (miR-27a, miR-196a2, miR-423) Gene Variations as a Risk Factor in the Genetic Predisposition to PCOS

Polycystic ovary syndrome (PCOS) is a disorder with a symptomatic manifestation of an array of metabolic and endocrine impairments. PCOS has a relatively high prevalence rate among young women of reproductive age and is a risk factor for some severe metabolic diseases such as T2DM, insulin insensitivity, and obesity, while the most dominant endocrine malfunction is an excess of testosterone showing hyperandrogenism and hirsutism. MicroRNAs have been implicated as mediators of metabolic diseases including obesity and insulin resistance, as these can regulate multiple cellular pathways such as insulin signaling and adipogenesis. Genome-wide association studies during the last few years have also linked the Krüpple-like family of transcription factors such as KLF14, which contribute in mechanisms of mammalian gene regulation, with certain altered metabolic traits and risk of atherosclerosis and type-2 DM. This study has characterized the biochemical and endocrine parameters in PCOS patients with a comprehensive serum profiling in comparison to healthy controls and further examined the influence of allelic variations for miRNAs 27a (rs895819 A > G), 196a2 (rs11614913 C > T), 423 (rs6505162C > A), and transcription factor KLF14 (rs972283 A > G) gene polymorphism on the risk and susceptibility to PCOS. The experimental protocol included amplification refractory mutation-specific (ARMS)-PCR to detect and determine the presence of these polymorphic variants in the study subjects. The results in this case−control study showed that most of the serum biomarkers, both biochemical and endocrine, that were analyzed in the study demonstrated statistically significant alterations in PCOS patients, including lipids (LDL, HDL, cholesterol), T2DM markers (fasting glucose, free insulin, HOMA-IR), and hormones (FSH, LH, testosterone, and progesterone). The distribution of Krüppel-like factor 14 rs972283 G > A, miR-27a rs895819 A > G, and miR-196a-2 rs11614913 C > T genotypes analyzed within PCOS patients and healthy controls in the considered population was significant (p < 0.05), except for miR-423 rs6505162 C > A genotypes (p > 0.05). The study found that in the codominant model, KLF14-AA was strongly associated with greater PCOS susceptibility (OR 2.35, 95% CI = 1.128 to 4.893, p < 0.022), miR-27a-GA was linked to an enhanced PCOS susceptibility (OR 2.06, 95% CI = 1.165 to 3.650, p < 0.012), and miR-196a-CT was associated with higher PCOS susceptibility (OR 2.06, 95% CI = 1.191 to 3.58, p < 0.009). Moreover, allele A of KLF-14 and allele T of miR-196a2 were strongly associated with PCOS susceptibility in the considered population.

Biochemical Characterization and Molecular Determination of Estrogen Receptor-α (ESR1 PvuII-rs2234693 T>C) and MiRNA-146a (rs2910164 C>G) Polymorphic Gene Variations and Their Association with the Risk of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is regarded as one of the most frequently encountered endocrine disorders and affects millions of young women worldwide, resulting in an array of complex metabolic alterations and reproductive failure. PCOS is a risk factor for diabetes mellitus, obstructive sleep apnea, obesity and depression in patients. Estrogen receptors (ESRs) are significant candidates in endocrine function and ovarian response in women. Moreover, microRNAs and long non-coding RNAs are emerging as principal mediators of gene expression and epigenetic pathways in various disease states. This study has characterized the clinical parameters in PCOS patients with comprehensive biochemical profiling compared to healthy controls and further examined the influence of allelic variations for estrogen receptor-α (ESR1 PvuII-rs2234693 T>C) and miRNA-146a (rs2910164 C>G) gene polymorphism on the risk of and susceptibility to PCOS. In this case-control study, we have used amplification refractory mutation specific (ARMS)-PCR to detect and determine the presence of these polymorphic variants in the study subjects. Our results demonstrated that most of the biochemical markers, which were analyzed in the study, show statistically significant alterations in PCOS patients, including fasting glucose, free insulin, HOMA-IR, LDL, HDL, cholesterol and hormones such as FSH, LH, testosterone and progesterone, which correlate with the established biochemical alterations in the disorder. Further, it is reported that for estrogen receptor-α (ESR1 PvuII-rs2234693 T>C), the frequency of the T allele (fT) was significantly higher among patients (0.64 vs. 0.44) compared to controls, while the frequency of the C allele (fC) was lower in patients (0.36 vs. 0.56) compared to controls. However, it was found that there was no association of an increased risk of PCOS with the ESR1 PvuII-rs2234693 C>T gene polymorphism. On the contrary, the study found strong association of miRNA-146a (rs2910164 C>G) gene polymorphism with an enhanced risk of PCOS. The frequency of the C allele (fC) was significantly higher among patients (0.52 vs. 0.36) compared to controls. The frequency of the G allele (fG) was found to be lower in patients (0.48 vs. 0.64) compared to controls. The codominant, dominant and recessive models display a statistically significant association of polymorphic variations with PCOS. Moreover, the G allele was associated strongly with PCOS susceptibility with an OR = 1.92 (95%) CI = (1.300−2.859), RR = 1.38 (1.130−1.691) p-value < 0.001.

The Effect of SOCS2 Polymorphisms on Type 2 Diabetes Mellitus Susceptibility and Diabetic Complications in the Chinese Han Population

Background

SOCS2 is downregulated in diabetes, which might be related to diabetes. We explored the effect of SOCS2 polymorphisms on the development of type 2 diabetes mellitus (T2DM) and diabetic complications.

Methods

The subjects consisted of 500 patients with T2DM and 501 healthy controls. Five variants in SOCS2 were genotyped by Agena MassARRAY system. RT-qPCR profiling was performed to detect the expression of SOCS2 mRNA. Logistic regression analysis was utilized to calculate odds ratio (OR) and 95% confidence intervals (95% CIs).

Results

Rs3825199 (OR = 1.44, p = 0.007), rs11107116 (OR = 1.39, p = 0.014) and rs10492321 (OR = 1.48, p = 0.004) had an increased T2DM risk of T2DM. Moreover, the contribution of SOCS2 polymorphisms to T2DM risk was associated with age, gender, smoking, drinking, and BMI. SOCS2 variants also had a reduced risk for T2DM patients with diabetic nephropathy, diabetic retinopathy and coronary heart disease. SOCS2 rs10492321 was the best single locus model. SOCS2 mRNA was downregulated in patients with T2DM compared to healthy controls (p = 0.029).

Conclusion

This study firstly reported that rs3825199, rs11107116 and rs10492321 in SOCS2 conferred to an increased risk for the occurrence of T2DM in the Chinese Han population. Moreover, SOCS2 mRNA was downregulated in patients with T2DM, suggesting that SOCS2 might have an important role in the occurrence of T2DM.

Biological and clinical implications of TNF-α promoter and CYP1B1 gene variations in Coronary Artery Disease susceptibility

BACKGROUND

Cardiovascular diseases (CVD) are important causes of death worldwide. Atherosclerosis is a chronic inflammatory disorder. It is the major cause of CVD and is manifested by ischemic heart disease or coronary artery disease (CAD). TNF-α is a pro-inflammatory cytokine that regulates immune response and promotes the development of atherosclerosis. Cytochrome p450 1B1 (CYP1B1) is an enzyme involved in the metabolism of endogenous and exogenous substrates.

OBJECTIVES

This study aimed at examining the association of TNF-α rs1800629 G >A and CYP1B1 rs1056827 G>T gene polymorphisms with CAD susceptibility in an Indian cohort.

METHODS

AS-PCR and direct DNA sequencing were used to examine the association of TNF-α rs1800629 G >A and CYP1B1 rs1056827 G>T gene polymorphism with CAD in an Indian cohort. A total of 100 clinically confirmed cases of CAD and 110 matched apparently healthy controls were genotyped.

RESULTS

Allelic and genotypic frequencies did not deviate from Hardy-Weinberg equilibrium in the controls (p>0.05) for TNF-α G-308A and CYP1B1 rs1056827G>A. There was no significant difference between the TNF-α rs1800629 A>G genotype distribution between cases and controls (P-value >0.05). A significant difference was observed between the CYP1B1 rs1056827 G>T genotype distribution between CAD cases and controls (P<0.0003). Our result indicated that in the codominant model, the GA genotype of the CYP1B1 rs1056827 G>T was associated with CAD with OR= 2.21(1.17 to 4.15), RR=1.38(1.07 to 1.78), and P<0.013. In the dominant model, the (GA+AA) genotype was associated with CAD with OR=2.79(1.54 to 5.05) and P<0.007. The CYP1B1 rs1056827 'A' allele was associated with CAD with OR = 2.30 (1.55 to 3.42) and P< 0.0001. Our results indicated that TNF-α 1800629 gene polymorphism was strongly associated with hypercholesteremia (P<0.0009), HDL (P<0.0001), TGL (P<0.039), hypertension (P<0.0001), and smoking (P<0.0001) in patients with Coronary Artery Disease. Similar correlations of CYP1B1 rs1056827 genotypes were reported with cholesterol (P<0.020), HDL (P<0.002), LDL (P<0.006), hypertension (P<0.03), and smoking (P<0.005).

CONCLUSION

It was reported that the GA genotype of the CYP1B1 rs1056827 G>T was strongly associated with susceptibility to Coronary Artery Disease with OR= 2.21(1.17 to 4.15)) and P<0.013, and similarly, its A allele was associated with predisposition to CAD with OR = 2.30(1.55 to 3.42) and P< 0.0001. Our results indicated that TNF-α 1800629 gene polymorphism is not associated with predisposition to Coronary Artery Disease. Nevertheless, these results should be taken with caution and further validated with larger-scale studies before being introduced in the clinical setting.

Clinical Implications of MiR128, Angiotensin I Converting Enzyme and Vascular Endothelial Growth Factor Gene Abnormalities and Their Association with T2D

Type 2 DM (T2D) results from the interaction of the genetic and environmental risk factors. Vascular endothelial growth factor (VEGF), angiotensin I-converting enzyme (ACE), and MicroRNAs (MiRNAs) are involved in important physiological processes. Gene variations in VEGF, ACE and MiRNA genes are associated with diseases. In this study we investigated the associations of the VEGF-2578 C/A (rs699947), VEGF-2549 insertion/deletion (I/D), and ACE I/D rs4646994 and Mir128a (rs11888095) gene variations with T2D using the amplification refractory mutation system PCR (ARMS-PCR) and mutation specific PCR (MSP). We screened 122 T2D cases and 126 healthy controls (HCs) for the rs699947, and 133 T2D cases and 133 HCs for the VEGF I/D polymorphism. For the ACE I/D we screened 152 cases and 150 HCs, and we screened 129 cases and 112 HCs for the Mir128a (rs11888095). The results showed that the CA genotype of the VEGF rs699947 and D allele of the VEGF I/D polymorphisms were associated with T2D with OR =2.01, p-value = 0.011, and OR = 2.42, p-value = 0.010, respectively. The result indicated the D allele of the ACE ID was protective against T2D with OR = 0.10, p-value = 0.0001, whereas the TC genotype and the T allele of the Mir128a (rs11888095) were associated with increased risk to T2D with OR = 3.16, p-value = 0.0001, and OR = 1.68, p-value = 0.01, respectively. We conclude that the VEGF (rs699947), VEGF I/D and Mir128a (rs11888095) are potential risk loci for T2D, and that the D allele of the ACE ID polymorphism may be protective against T2D. These results help in identification and stratification for the individuals that at risk for T2D. However, future well-designed studies in different populations and with larger sample sizes are required. Moreover, studies to examine the effects of these polymorphisms on VEGF and ACE proteins are recommended.