RyR2/IRBIT regulates insulin gene transcript, insulin content, and secretion in the insulinoma cell line INS-1

The role of ER Ca2+ release via ryanodine receptors (RyR) in pancreatic β‐cell function is not well defined. Deletion of RyR2 from the rat insulinoma INS‐1 (RyR2KO) enhanced IP3 receptor activity stimulated by 7.5 mM glucose, coincident with reduced levels of the protein IP3 Receptor Binding protein released with Inositol 1,4,5 Trisphosphate (IRBIT). Insulin content, basal (2.5 mM glucose) and 7.5 mM glucose‐stimulated insulin secretion were reduced in RyR2KO and IRBITKO cells compared to controls. INS2 mRNA levels were reduced in both RyR2KO and IRBITKO cells, but INS1 mRNA levels were specifically decreased in RyR2KO cells. Nuclear localization of S‐adenosylhomocysteinase (AHCY) was increased in RyR2KO and IRBITKO cells. DNA methylation of the INS1 and INS2 gene promotor regions was very low, and not different among RyR2KO, IRBITKO, and controls, but exon 2 of the INS1 and INS2 genes was more extensively methylated in RyR2KO and IRBITKO cells. Exploratory proteomic analysis revealed that deletion of RyR2 or IRBIT resulted in differential regulation of 314 and 137 proteins, respectively, with 41 in common. These results suggest that RyR2 regulates IRBIT levels and activity in INS‐1 cells, and together maintain insulin content and secretion, and regulate the proteome, perhaps via DNA methylation

The impact of diabetes prevention on labour force participation and income of older Australians: an economic study

Background: Globally, diabetes is estimated to affect 246 million people and is increasing. In Australia diabetes has been made a national health priority. While the direct costs of treating diabetes are substantial, and rising, the indirect costs are considered greater. There is evidence that interventions to prevent diabetes are effective, and cost-effective, but the impact on labour force participation and income has not been assessed. In this study we quantify the potential impact of implementing a diabetes prevention program, using screening and either metformin or a lifestyle intervention on individual economic outcomes of pre-diabetic Australians aged 45-64. Methods. The output of an epidemiological microsimulation model of the reduction in prevalence of diabetes from a lifestyle or metformin intervention, and another microsimulation model, Health&WealthMOD, of health and the associated impacts on labour force participation, personal income, savings, government revenue and expenditure were used to quantify the estimated outcomes of the two interventions. Results: An additional 753 person years in the labour force would have been achieved from 1993 to 2003 for the male cohort aged 60-64 years in 2003, if a lifestyle intervention had been introduced in 1983; with 890 person years for the equivalent female group. The impact on labour force participation was lower for the metformin intervention, and increased with age for both interventions. The male cohort aged 60-64 years in 2003 would have earned an additional $30 million in income with the metformin intervention, and the equivalent female cohort would have earned an additional$25 million. If the lifestyle intervention was introduced, the same male and female cohorts would have earned an additional $34 million and$28 million respectively from 1993 to 2003. For the individuals involved, on average, males would have earned an additional $44,600 per year and females an additional$31,800 per year, if they had continued to work as a result of preventing diabetes. Conclusions: In addition to improved health and wellbeing, considerable benefits to individuals, in terms of both additional working years and increased personal income, could be made by introducing either a lifestyle or metformin intervention to prevent diabetes

Crop pests and predators exhibit inconsistent responses to surrounding landscape composition

The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies

Minimum Information about a Biosynthetic Gene cluster

A wide variety of enzymatic pathways that produce specialized metabolites in bacteria, fungi and plants are known to be encoded in biosynthetic gene clusters. Information about these clusters, pathways and metabolites is currently dispersed throughout the literature, making it difficult to exploit. To facilitate consistent and systematic deposition and retrieval of data on biosynthetic gene clusters, we propose the Minimum Information about a Biosynthetic Gene cluster (MIBiG) data standard.Chemistry and Chemical Biolog

Investigating the Role of Ryr2 In Ca2+Dynamics, Insulin Secretion, and Electrophysiological Properties in Pancreatic B-cells

The role of the endoplasmic reticulum (ER) Ca2+release channels ryanodine receptor 2 (RyR2) and inositol 1,4,5-triphosphate receptor (IP3R) in pancreatic b-cell function are emerging, but are not well defined. It has been demonstrated that ER stress brought about by RyR2 dysfunction leads to impaired insulin secretion and contributes to the etiology of type 2 diabetes (T2D). Our work contributes to the understanding of the role of RyR2 in physiological pancreatic b-cell function and how loss of RyR2 contributes to the pathophysiology of T2D. To investigate the role of RyR2 in pancreatic b-cell function, we utilized CRISPR-Cas9 to delete RyR2 from the rat insulinoma INS-1 cell line (RyR2KO). We found that RyR2KO cells displayed an enhanced glucose-stimulated Ca2+ integral (area under the curve; AUC) and were sensitive to inhibition by the IP3R antagonist, xestospongin C. Loss of RyR2 also resulted in a reduction in IRBIT protein levels. Therefore, we deleted IRBIT from INS-1 cells (IRBITKO) and found that IRBITKO cells also displayed an increased Ca2+ AUC in response to glucose stimulation. We discovered that total cellular insulin content and secretion were reduced in RyR2KO cells, but more modestly reduced in IRBITKO cells. We found that INS2 mRNA levels were reduced in both RyR2KO and IRBITKO cells, but INS1 mRNA levels were specifically decreased in RyR2KO cells. Additionally, nuclear localization of S-adenosylhomocysteinase (AHCY) was increased in both RyR2KO and IRBITKO cells. DNA methylation of exon 2 of the INS1 and INS2 genes was more extensively methylated in RyR2KO and IRBITKOcells compared to controls. Proteomics analysis revealed that deletion of RyR2 or IRBIT resulted in differential regulation of 314 and 137 proteins, respectively, with 41 in common. Our results suggest that RyR2 regulates IRBIT levels and activity, and together maintain insulin content and secretion, and regulate the INS-1 cell proteome, perhaps via DNA methylation. The role of interplay between RyR2 and IP3R in Ca2+ signaling and homeostasis in pancreatic b-cell function remains understudied. Stimulation with the sulfonylurea tolbutamide resulted in markedly delayed Ca2+ transients in both RyR2KO and IRBITKO cells. Xestospongin C significantly reduced the AUC of Ca2+ in RyR2KO and IRBITKO cells. Muscarinic receptor stimulation revealed a markedly increased AUC of Ca2+ in IRBITKO cells compared to both RyR2KO and control INS-1 cells. Assessment of PLC activity revealed that basal and stimulated PLC activity were reduced in the absence of RyR2 or IRBIT. Store-operated Ca2+ entry (SOCE) following ER Ca2+ depletion revealed a decreased SOCE amplitude only in RyR2KO cells. Given evidence that phosphatidylinositol-4,5-bisphosphate (PIP2) depletion from the plasma membrane can regulate voltage-gated Ca2+ channel inhibition, we explored electrophysiological properties of all three cell lines. The frequency of glucose-stimulated action potentials was doubled in RyR2KO cells. Additionally, whole-cell voltage-gated Ca2+ current density was doubled in RyR2KO cells, and this current was more sensitive to hydrolysis of PIP2. These results evidence crosstalk between RyR2 and IP3R, and that RyR2 plays a critical role in maintaining proper Ca2+homeostasis, PLC activity, and electrophysiological properties in pancreatic b-cells

Molecular actions of Vitamin D in reproductive cell biology

Vitamin D (VitD) is an important secosteroid and has attracted attention in several areas of research due to common VitD deficiency in the population, and its potential to regulate molecular pathways related to chronic and inflammatory diseases. VitD metabolites and the VitD receptor (VDR) influence many tissues including those of the reproductive system. VDR expression has been demonstrated in various cell types of the male reproductive tract, including spermatozoa and germ cells, and in female reproductive tissues including the ovaries, placenta and endometrium. However, the molecular role of VitD signalling and metabolism in reproductive function have not been fully established. Consequently, the aim of this work is to review current metabolic and molecular aspects of the VitD-VDR axis in reproductive medicine and to propose the direction of future research. Specifically, the influence of VitD on sperm motility, calcium handling, capacitation, acrosin reaction and lipid metabolism is examined. In addition, we will also discuss the effect of VitD on sex hormone secretion and receptor expression in primary granulosa cells, along with the impact on cytokine production in trophoblast cells. The review concludes with a discussion of the recent developments in VitD-VDR signalling specifically related to altered cellular bioenergetics, which is an emerging concept in the field of reproductive medicine