Expression Silencing of Mitogen-Activated Protein Kinase 8 Interacting Protein-1 Conferred Its Role in Pancreatic β-Cell Physiology and Insulin Secretion

Mitogen-activated protein kinase 8 interacting protein-1 (MAPK8IP1) gene has been recognized as a susceptibility gene for diabetes. However, its action in the physiology of pancreatic β-cells is not fully understood. Herein, bioinformatics and genetic analyses on the publicly available database were performed to map the expression of the MAPK8IP1 gene in human pancreatic islets and to explore whether this gene contains any genetic variants associated with type 2 diabetes (T2D). Moreover, a series of functional experiments were executed in a rat insulinoma cell line (INS-1 832/13) to investigate the role of the Mapk8ip1 gene in β-cell function. Metabolic engineering using RNA-sequencing (RNA-seq) data confirmed higher expression levels of MAPK8IP1 in human islets compared to other metabolic tissues. Additionally, comparable expression of MAPK8IP1 expression was detected in sorted human endocrine cells. However, β-cells exhibited higher expression of MAPK8IP1 than ductal and PSC cells. Notably, MAPK8IP1 expression was reduced in diabetic islets, and the expression was positively correlated with insulin and the β-cell transcription factor PDX1 and MAFA. Using the TIGER portal, we found that one genetic variant, "rs7115753," in the proximity of MAPK8IP1, passes the genome-wide significance for the association with T2D. Expression silencing of Mapk8ip1 by small interfering RNA (siRNA) in INS-1 cells reduced insulin secretion, glucose uptake rate, and reactive oxygen species (ROS) production. In contrast, insulin content, cell viability, and apoptosis without cytokines were unaffected. However, silencing of Mapk8ip1 reduced cytokines-induced apoptosis and downregulated the expression of several pancreatic β-cell functional markers including, Ins1, Ins2, Pdx1, MafA, Glut2, Gck, Insr, Vamp2, Syt5, and Cacna1a at mRNA and/or protein levels. Finally, we reported that siRNA silencing of Pdx1 resulted in the downregulation of MAPK8IP1 expression in INS-1 cells. In conclusion, our findings confirmed that MAPK8IP1 is an important component of pancreatic β-cell physiology and insulin secretion.

GDF15 plays a critical role in insulin secretion in INS-1 cells and human pancreatic islets

Mounting evidence points to a link between growth differentiation factor-15 (GDF15) expression and the onset and progression of diabetes mellitus. However, the exact role of GDF15 in pancreatic β-cell function is unclear. To examine the role of GDF15 in β-cell function, bioinformatics analysis and functional experiments involving GDF15 silencing and overexpression were performed in INS-1 cells and human islets. Public microarray and RNA-seq expression data showed that islets obtained from diabetic donors express high levels of GDF15 compared to islets obtained from normal donors. Moreover, analysis of RNA-seq expression data revealed that GDF15 expression correlates positively with that of insulin (INS), KCNJ11, GLUT1, MAFA, INSR and negatively with that of Glucokinase (GCK) and Alpha-Ketoglutarate Dependent Dioxygenase (FTO). No T2D-associated genetic variants in the GDF15 were found to pass genome-wide significance in the TIGER portal. Expression silencing of Gdf15 in INS-1 cells reduced insulin release, glucose uptake levels, increased reactive oxygen species (ROS) production and apoptosis levels. While Gdf15-silenced cells downregulated mRNA expression of Ins, Pdx1, Mafa, and Glut2 genes, its overexpression human islets was associated with increased insulin secretion and upregulated expression of MAFA and GLUT1 but not INS or GCK. Silencing of Pdx1 or Mafa in INS-1 cells did not affect the expression of GDF15. These findings suggest that GDF15 plays a significant role in pancreatic β-cell function.

Copine 3 "CPNE3" is a novel regulator for insulin secretion and glucose uptake in pancreatic β-cells

Copine 3 (CPNE3) is a calcium-dependent phospholipid-binding protein that has been found to play an essential role in cancer progression and stages. However, its role in pancreatic β-cell function has not been investigated. Therefore, we performed a serial of bioinformatics and functional experiments to explore the potential role of Cpne3 on insulin secretion and β-cell function in human islets and INS-1 (832/13) cells. RNA sequencing and microarray data revealed that CPNE3 is highly expressed in human islets compared to other CPNE genes. In addition, expression of CPNE3 was inversely correlated with HbA1c and reduced in human islets from hyperglycemic donors. Silencing of Cpne3 in INS-1 cells impaired glucose-stimulated insulin secretion (GSIS), insulin content and glucose uptake efficiency without affecting cell viability or inducing apoptosis. Moreover, mRNA and protein expression of the key regulators in glucose sensing and insulin secretion (Insulin, GLUT2, NeuroD1, and INSR) were downregulated in Cpne3-silenced cells. Taken together, data from the present study provides a new understanding of the role of CPNE3 in maintaining normal β-cell function, which might contribute to developing a novel target for future management of type 2 diabetes therapy.

Effect of heating on the oxidative stability of corn oil and soybean oil

The effects of conventional and microwave heating on the oxidative properties of corn and soybean oil were evaluated. The results showed that acid value, peroxide value, oxidative indices, total oxidation value, and p-anisidine values changed significantly with the rise in temperature (p < 0.05). The peroxide and p-anisidine values for corn oil (PV: 50.670 meqO2/kg, p-AV: 8.248) were greater than soybean oil (PV: 41.694 meqO2/kg, p-AV: 7.566) for conventional heating. The peroxide and p-anisidine values for soybean oil (PV: 6.545 meqO2/kg, p-AV: 76.539) were greater compared to corn oil (PV: 5.074 meqO2/kg, p-AV: 65.360) for microwave heating. The results concluded that microwave heating had a greater impact on the chemical degradation of the fatty acids of the oil. The FT-IR spectra showed peak changes at 3743 cm-1 and 1739 cm-1 and confirmed the rancidity of the oils from microwave heating due to the formation of secondary oxidation products. It was concluded that corn oil showed more oxidative changes compared to soybean oil.

Varietal Preferences and Within-Orchard and Tree Distribution of Newly Recorded Gall Midges, Dasineura amaramanjarae and Procontarinia mangiferae (Diptera: Cecidomyiidae), From Commercial Mango Cultivars in Pakistan

Gall midges (Diptera: Cecidomyiidae) damage mango by feeding on flowers and fruit tissues, inducing galls on leaves, and providing inoculums of anthracnose. Dasineura amaramanjarae Grover and Procontarinia mangiferae (Felt), two gall midges that damage flowers in all mango-growing areas of the world, have recently been recorded in Pakistan, and studies were conducted in 2011 and 2012 on the within-tree and orchard distribution patterns and cultivar preference of both species in Pakistan at one location (Rahim Yar Khan). Both gall midge species were found on all mango cultivars examined (Chaunsa, Fajri, Dusehri, Surkha, Sindhri, and Anwar Ratul), with the most damage occurring to Surkha and Dusehri. Research on midge distribution patterns in different parts of mango orchards (central, southern, northern, eastern, and western sides) showed these species to be found in all areas, with the greatest numbers in the central and southern regions. In addition, both species were most abundant on the lower parts of the mango tree canopy.

Value of kidney-ureter-bladder radiography in the erect position in addition to standard intravenous urography examination

OBJECTIVES

To determine if additional kidney-ureter-bladder radiography in the erect position can improve the diagnostic yield of standard intravenous urography (IVU) examination.

SUBJECTS AND METHODS

This prospective study was conducted from March to July 2007 on 108 consecutive patients (65 males and 43 females, age ranging from 20 to 50 years) who were referred to the Department of Radiology, Al-Amiri Hospital, Kuwait, for IVU examinations. After 15 min, a film was done in the erect position in addition to the routine IVU protocol.

RESULTS

Additional information was demonstrated in the erect radiograph as follows: detecting nephroptosis in 18 (17%) patients, improved visualization of the ureters in 58 (54%) patients, and differentiation between phleboliths and ureteric stone was possible in 12 (11%) patients.

CONCLUSIONS

Our study demonstrated significant additional findings in the erect position (at 15 min) compared to the supine position.

Kinetics of bromination of safranine by peroxydisulphate ion in presence of bromide ion

Kinetics of bromination safranine by peroxydisulphate ion in presence of bromide ion has been investigated at various temperatures and ionic strengths. The rate followed first order kinetics in peroxy disulphate and bromide ion each, and zero order kinetics in safranine. A linear relation was obtained for the variation of logarithm of rate constant (log k) with the square root of ionic strength of the media (mu). The rate constants for the rate controlling step were evaluated and interpreted as a function of ionic strengths and temperatures. The values of activation parameters were also computed.

Renal transplant experience at king fahad national guard hospital

Between September 1988 and end of 1995, 170 renal transplantations were performed at the King Fahad National Guard Hospital, Riyadh. There were 102 cadaver donor (CAD) and 68 living related donor (LRD) transplants. All patients received triple drug immunosuppression. Patients with delayed graft function received anti-thymocyte globulin instead of cyclosporin until recovery of graft function. The 1,3 and 5 year graft survival was as follows: all transplants 83.5%, 77.6%, 74.7% respectively; LRD transplants, 89.7%, 85.2%, 80.9% respectively; CAD transplants, 81.0%, 72.5%, 70.5% respectively. The commonest cause of graft loss was chronic rejection. The 1,3 and 5 year patient survival was as follows: all transplants, 97.0%, 94.7%, 93.5% respectively; LRD transplants, 98.5%, 97.0%, 95.5% respectively; CAD transplants, 96.0%, 93.0%, 92.0% respectively. The overall results in our center are comparable to those published from other centers in Saudi Arabia and abroad.