Calpain-10 Research Articles

111/121 diplotype of Calpain-10 is associated with the risk of polycystic ovary syndrome in Korean women

We investigated whether the CAPN-10 polymorphism UCSNP-43, -19, and -63 contribute, either individually or as haplotype/diplotype, to the susceptibility of polycystic ovary syndrome (PCOS) or related quantitative traits in Korean women. Our data showed that 111 haplotype and 111/121 and 111/111 diplotypes in the CAPN-10 gene were associated with a significantly increased risk of PCOS, and 112 haplotype and 121/121 and 112/122 diplotypes were associated with decreased risk of PCOS in the Korean population.

Association of calpain-10 polymorphisms with type 2 diabetes in the Tunisian population

Background Genome-wide analyses of the genetic predisposition to type 2 diabetes mellitus (T2DM) in different isolates and populations have identified regions of interest called non insulin-dependent diabetes mellitus (NIDDM) 1, 2, 3 and 4. At the NIDDM1 locus (2q37.3), calpain-10 ( CAPN10) encodes for a ubiquitously expressed protease implicated in the two fundamental pathophysiological aspects of T2DM. This is a report of the results of a study of the association of four CAPN10 polymorphisms with T2DM in the Tunisian population. Participants and methods A total of 222 T2DM patients with a diabetes duration of 10 years or more and 206 healthy controls were enrolled to analyze the frequency distribution of four CAPN10 polymorphisms (UCSNP-43, UCSNP-19, UCSNP-110 and UCSNP-63) using polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) in the Tunisian population. We also investigated the association of T2DM with different haplotypes and haplotype combinations. Results Only the A allele of UCSNP-43 showed an association with T2DM (odds ratio, OR = 1.86). We also identified a novel combination of haplotypes (121/221) defined by three polymorphisms (UCNSP-43, -19 and -63) that is associated with an increased risk of T2DM (OR = 2.38). Conclusion In this study involving the Tunisian population, we identified genetic variants within CAPN10 that are linked with T2DM and a novel haplotype combination, 121/221, associated with an increased susceptibility to T2DM.

Cloning, expression, and polymorphism of the porcine calpain10 gene

Calpains are calcium-regulated proteases involved in cellular functions that include muscle proteolysis both ante- and post-mortem. This study was designed to clone the complete coding sequence of the porcine calpain10 gene, CAPN10, to analyze its expression characteristics and to investigate its polymorphism. Two isoforms of the CAPN10 gene, CAPN10A and CAPN10B, were obtained by reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends methods combined with in silico cloning. RT-PCR results indicated that CAPN10 mRNA was ubiquitously expressed in all tissues examined and, with increasing age, the expression level increased in muscles at six different growth points. In the same tissues, the expression level of CAPN10A was higher than that of CAPN10B. In addition, three single nucleotide polymorphisms were detected by the PCR-single-stranded conformational polymorphism method and by comparing the sequences of Chinese Min pigs with those of Yorkshire pigs. C527T mutation was a missense mutation and led to transforming Pro into Leu at the 176 th amino acid. The results of the current study provided basic molecular information for further study of the function of the porcine CAPN10 gene.

Relationship between single nucleotide polymorphism-56 of calpain-10 gene and glucose and lipid metabolism in polycystic ovary syndrome patients

To investigate the relationship between single nucleotide polymorphism-56 (SNP-56) in calpain-10 (CAPN-10) gene and polycystic ovary syndrome (PCOS) in Chinese. The genotypes of SNP-56 of CAPN-10 were determined through polymerase chain reaction Tm-shift genotyping method in 638 local women in Shandong Province. Among them, 334 were patients with PCOS (PCOS group) and 304 were normal women (control group). The baseline parameters including levels of serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), estradiol (E2), testosterone (T) and lipid,as well as the body mass index (BMI) and waist/hip ratio (WHR) were measured. Glucose tolerance and insulin releasing before and after loading with 75 g of glucose were also assayed. (1) The frequencies of two allelotypes or three genotypes did not differ between PCOS women and normal women (P > 0.05). (2) In PCOS group, patients with AA genotype had a significantly higher plasma glucose of 180 minutes OGTT (5.7 +/- 2. 2)mmol/L [P < 0.01 compared to GA genotype (4.9 +/- 1.2) mmol/L, P < 0.01 compared to GG genotype (4.9 +/- 1.4) mmol/L] and serum total cholesterol (TC) level (4.9 +/- 1.0) mmol/L [P < 0.05 compared to GA genotype (4.5 +/- 0.9) mmol/L]. (3) Compared to PCOS patients with GA + GG genotype (P < 0.05, P < 0.01) or GG genotype (P < 0.05, P < 0.01), there was significantly higher attack rate of diabetes and tumor in the family history of patients with AA genotype. These findings suggest that CAPN-10 gene SNP-56 which may not contribute to the genetic susceptibility of PCOS plays a role in glucose and lipid metabolism in Chinese PCOS patients. It may also be correlated with attack rate of diabetes and tumor in the family history of PCOS patients.

Calpain-10 Polymorphism in Korean Women with Polycystic Ovary Syndrome

Background: Polycystic ovary syndrome (PCOS) is characterized by chronic anovulation, hyperandrogenism and insulin resistance, and PCOS is known to be associated with an increased risk of type 2 diabetes mellitus (DM). PCOS has also been proposed to share a common genetic background with type 2 DM. The calpain 10 (CAPN10) gene is known to be associated with type 2 DM in several different population. We examined the association of CAPN10 gene polymorphisms and their influence on the metabolic abnormalities in Korean women who suffer with PCOS. Methods: One hundred sixty four women with PCOS and 325 control women were studied. The CAPN10 gene polymorphisms were genotyped by amplifying the genomic DNA. Anthropometric measures, a 75g oral glucose tolerance test and measurement of insulin sensitivity by the euglycemic hyperinsulinemic clamp technique were performed. Results: The frequencies of CAPN10 UCSNP-43, UCSNP-19, UCSNP-63 and the haplotype combinations were not different between the women with PCOS and the control subjects. In the women with PCOS and who had the UCSNP-43 GA genotype, the post-load 90 minute plasma glucose level was significantly greater and the HDL cholesterol and insulin mediated glucose uptake were significantly lower compared to the women with PCOS and who had the GG genotype. Conclusion: The CAPN10 UCSNP-43 genotype might be responsible for insulin resistance, yet further study is required to confirm the role of this genetic polymorphism in the development of PCOS and the presentation of its disease features.

Variations in the calpain-10 gene are associated with the risk of type 2 diabetes and hypertension in northern Han Chinese population

Calpain-10 (CAPN10) has been identified as a susceptibility gene in type 2 diabetes mellitus (T2DM) and insulin resistance. The present study aimed to identify the effects of genetic variations in the CAPN10 gene on the development of type 2 diabetes and hypertension in northern Han Chinese population. We performed a case-control study and genotyped single nucleotide polymorphism (SNP)-44, -43, -19 and -63 of CAPN10 gene in 1046 subjects from the northern China, including 493 patients with T2DM and hypertension and 553 age- and gender-matched normal healthy controls. Univariate analysis showed that the four polymorphisms were not independently associated with T2DM and hypertension. However, the frequency distributions of SNP-44 allele C (allele 2) (17.89% vs 9.80%, P = 0.0016) and genotype CC (22) (4.21% vs 1.01%, P = 0.0059) in obese patients (body mass index > or = 30 kg/m2) were different from those in non-obese patients. Logistic regression analyses revealed that carriers of the 1112/1221 diplotype had a significantly lower odds ratio for diabetes and hypertension (OR = 0.399, 95% CI, 0.196 - 0.814, P = 0.0115). The 1112/1121 diplotype associated with significantly increased risk of type 2 diabetes in Mexican-American was not associated with the increased risk in Chinese. These results suggested that CAPN10 gene variations might play roles in the risk of diabetes and hypertension in northern Han Chinese population.

Identification of a protective haplogenotype within CAPN10 gene influencing colorectal cancer susceptibility

Colorectal cancer (CRC) is one of the most prevalent types of cancer affecting both men and women in developed countries. Clinical and molecular evidence suggests that there are multiple biochemical pathways involved in its susceptibility, pathogenesis and prognosis. Several studies have reported a significant association between the incidence of CRC and type 2 diabetes mellitus (T2DM). However, genes associated with both conditions are rare. We have analyzed the CAPN10 gene, a T2DM locus, using UCSNP-43, -44, -19, and -63 markers, looking for differences between 371 CRC patients and 605 unrelated controls of Spanish origin. We found that UCSNP-44 allele C is swept out from cases (OR = 0.16, P = 0.005). Moreover, the frequency of 2111/2111 haplogenotype is also statistically lower than expected in CRC patients (P = 0.006). Taken together, our results indicate a recessive model for the effect of CAPN10 variant UCSNP-44 influencing the risk of CRC and suggest a novel genetic link between T2DM and colon carcinoma.

Common genetic variation in calpain-10 gene (CAPN10) and diabetes risk in a multi-ethnic cohort of American postmenopausal women

Calpain-10 (CAPN10) protein may play a role in glucose metabolisms, pancreatic beta-cell insulin secretion and thermogenesis. Emerging evidence has implicated a role of CAPN10 genetic variants in the risk of type 2 diabetes mellitus (T2DM). Previous association studies, however, have focussed only on several variants initially reported and provided inconsistent results. We conducted a large nested case-control study to comprehensively investigate the associations between common variations in CAPN10 gene and T2DM risk among postmenopausal women aged 50-79 years from the Women's Health Initiative Observational Study. After comprehensive screening in 244 randomly chosen control samples (n = 61 for each of four ethnic groups), we selected a total of 12 tagging single nucleotide polymorphisms (tSNPs) spanning 91 kb in CAPN10 and genotyped them in 1543 diabetes cases and 2132 matched controls (including 968 cases and 968 controls for whites, 366 and 732 for blacks, 152 and 303 for Hispanics and 98 and 195 for Asian/Pacific Islanders). There were no significant associations between any individual tSNP and T2DM, within either the full study sample or any specific ethnic group. Nor was there any evidence of association between common CAPN10 haplotypes and diabetes risk (global tests for differences in risk were P = 0.31 for overall common haplotypes, P = 0.44 for haplotypes in block 1 and P = 0.37 for haplotypes in block 2). In conclusion, we did not observe any significant associations of the common SNPs or haplotypes across the CAPN10 gene with diabetes risk in our large and ethnically diverse cohort of postmenopausal women.

Variants of the Transcription Factor 7-Like 2 (TCF7L2) Gene Are Associated With Type 2 Diabetes in an African-American Population Enriched for Nephropathy

Recently, variants in the TCF7L2 gene have been reported to be associated with type 2 diabetes across multiple Europid populations, but only one small sample of African-American type 2 diabetic patients has been examined. Our objective was to investigate the importance of TCF7L2 in a larger African-American case-control population. We investigated single nucleotide polymorphisms (SNPs) in six known type 2 diabetes genes in 577 African-American case subjects with type 2 diabetes enriched for nephropathy and 596 African-American control subjects. Additionally, we genotyped 70 ancestry-informative markers (AIMs) to apply adjustments for differences in ancestral proportions. The most significant associations were observed with TCF7L2 intron 3 SNPs rs7903146 (additive P = 4.10 x 10(-6), odds ratio [OR] 1.51; admixture-adjusted P(a) = 3.77 x 10(-6)) and rs7901695 (P = 0.001, OR 1.30; P(a) = 0.003). The 2-SNP haplotype containing these SNPs was also associated with type 2 diabetes (P = 3 x 10(-5)). Modest associations were also seen with TCF7L2 intron 4 SNPs rs7895340, rs11196205, and rs12255372 (0.01 < P < 0.05; 0.03 < P(a) < 0.08), as well as with ATP-sensitive inwardly rectifying potassium channel subunit Kir6.2 (KCNJ11) and hepatocyte nuclear factor 4-alpha (HNF4A) SNPs (0.01 < P < 0.05; 0.01 < P(a) < 0.41). No significant associations were detected with genotyped calpain 10 (CAPN10), peroxisome proliferator-activated receptor gamma (PPARG), and transcription factor 1 (TCF1) SNPs. This study indicates that variants in the TCF7L2 gene significantly contribute to diabetes susceptibility in African-American populations.

Targeted suppression of calpain-10 expression impairs insulin-stimulated glucose uptake in cultured primary human skeletal muscle cells

Calpain-10 was identified as a novel type 2 diabetes susceptibility gene, although the mechanisms by which it increases susceptibility to type 2 diabetes remain unclear. As skeletal muscle is the principal site of the peripheral insulin resistance for glucose disposal in type 2 diabetes, we investigated whether targeted suppression of calpain-10 expression directly affects insulin action in cultured human skeletal muscle cells. Short interfering RNAs (siRNAs) were employed to specifically suppress CAPN10 gene expression. Suppression was seen at both the transcript and protein level, as assessed by quantitative PCR and Western blotting. Suppression of CAPN10 mRNA expression (75% decrease compared to untransfected myotubes) was associated with a significant decrease (p=0.04) in insulin-stimulated glucose uptake (1.03±0.06 [mean±SEM]-fold increase over basal) compared to the untransfected myotubes (1.43±0.16-fold increase). In contrast, decreased suppression of calpain-10 expression did not affect insulin-stimulated glycogen synthesis nor insulin-stimulated phosphorylation of protein kinase B, a key component of the insulin-signalling pathway.This study confirms that calpain-10 plays a role in insulin-stimulated glucose uptake in human skeletal muscle cells. Suppression of calpain-10 expression did not affect insulin-stimulated glycogen synthesis nor insulin-signalling via PKB, suggesting that calpain-10 may exert a direct regulatory effect upon the glucose uptake mechanism.

Calpain inhibition impairs glycogen syntheses in HepG2 hepatoma cells without altering insulin signaling

Calpains are a family of non-lysosomal cytoplasmatic cysteine proteases. Since calpain 10 (CAPN10), a member of the calpain family of proteases, has been found to represent a putative diabetes susceptibility gene, it was argued that calpains may be involved in the development of type 2 diabetes. The functional role of calpains in insulin signaling and/or insulin action is, however, not clear. We investigated the effects of the calpains 1 and 2 inhibitor PD151746 on insulin signaling and insulin action in human hepatoma G2 cells (HepG2). HepG2 cells were incubated without (-PD) or with (+PD) 5.33 micromol/l PD151746 for different times and then stimulated with 100 nmol/l insulin for 0 (t(0)), 5 (t(5)), 15 (t(15)), 30 (t(30)), 45 (t(45)), and 60 (t(60)) min. After solubilization of the cells, insulin receptor kinase activity, tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1), IRS-1-associated phosphatidylinositol-3 kinase (PI3-kinase), PI3-kinase activity, Thr(308) phosphorlyation of Akt, amount of protein tyrosine phosphatase-epsilon (PTPepsilon), and glycogen synthase activity were determined. Incubation with PD151746 resulted in a significant reduction of insulin-stimulated glycogen synthesis compared with cells not pre-incubated with the calpain inhibitor (-PD: t(0), 4.90 +/- 1.20%; t(5), 5.90 +/- 1.02%; t(15), 5.29 +/- 0.95%; t(30), 5.60 +/- 1.10%; t(45), 5.52 +/- 0.90%; t(60), 5.67 +/- 0.97%;+PD: t(0), 4.56 +/- 1.10%; t(5), 6.16 +/- 1.05%; t(15), 7.52 +/- 1.09%; t(30), 7.68 +/- 1.10%; t(45), 8.28 +/- 0.89%; t(60), 7.69 +/- 0.98%; P < 0.05). Incubation with PD151746 significantly increased the protein amount of PTPepsilon in the cells after 12 h (-PD: t(1), 0.85 +/- 0.18 RU (Relative unit); t(8), 0.87 +/- 0.18 RU; t(12), 0.9 +/- 0.13 RU; +PD: t(1), 0.92 +/- 0.21 RU; t(8), 1.1 +/- 0.15 RU; t(12), 1.34 +/- 0.16 RU; P < 0.05). Calpain inhibition with PD151746 had no effect on the insulin stimulation of the investigated insulin signaling parameters. These results in HepG2 cells suggest that calpains play a role in the hepatic regulation of insulin-stimulated glycogen synthesis independent of the PI3-kinase/Akt signaling pathway.

The genetics of the polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a very common endocrine disorder that has a strong genetic component and is characterized by polycystic ovaries, hyperandrogenemia, and menstrual irregularity. During the past decade, the roles of more than 70 candidate genes have been evaluated for a causal role in PCOS; however, because of genetic and phenotypic heterogeneity and underpowered studies, the results of many of these studies remain inconclusive. Here, the results of the genetic analysis of several candidate genes and gene regions-CYP11A (encoding cytochrome P450, family 11, subfamily A polypeptides), CAPN10 (encoding calpain 10), the insulin gene VNTR (variable number of tandem repeats), and D19S884 (a dinucleotide repeat marker mapping to chromosome 19p13.2)-are discussed in detail. Although past genetic studies of PCOS have yielded only modest results, resources and techniques have been assembled to remedy the major deficits of these early studies, promising that the next few years will be a very exciting and rewarding era for the genetic analysis of PCOS.

Calpain-5 gene variants are associated with diastolic blood pressure and cholesterol levels

BackgroundGenes implicated in common complex disorders such as obesity, type 2 diabetes mellitus (T2DM) or cardiovascular diseases are not disease specific, since clinically related disorders also share genetic components. Cysteine protease Calpain 10 (CAPN10) has been associated with T2DM, hypertension, hypercholesterolemia, increased body mass index (BMI) and polycystic ovary syndrome (PCOS), a reproductive disorder of women in which isunlin resistance seems to play a pathogenic role. The calpain 5 gene (CAPN5) encodes a protein homologue of CAPN10. CAPN5 has been previously associated with PCOS by our group. In this new study, we have analysed the association of four CAPN5 gene variants(rs948976A>G, rs4945140G>A, rs2233546C>T and rs2233549G>A) with several cardiovascular risk factors related to metabolic syndrome in general population.MethodsAnthropometric measurements, blood pressure, insulin, glucose and lipid profiles were determined in 606 individuals randomly chosen from a cross-sectional population-based epidemiological survey in the province of Segovia in Central Spain (Castille), recruited to investigate the prevalence of anthropometric and physiological parameters related to obesity and other components of the metabolic syndrome. Genotypes at the four polymorphic loci in CAPN5 gene were detected by polymerase chain reaction (PCR).ResultsGenotype association analysis was significant for BMI (p ≤ 0.041), diastolic blood pressure (p = 0.015) and HDL-cholesterol levels (p = 0.025). Different CAPN5 haplotypes were also associated with diastolic blood pressure (DBP) (0.0005 ≤ p ≤ 0.006) and total cholesterol levels (0.001 ≤ p ≤ 0.029). In addition, the AACA haplotype, over-represented in obese individuals, is also more frequent in individuals with metabolic syndrome defined by ATPIII criteria (p = 0.029).ConclusionAs its homologue CAPN10, CAPN5 seems to influence traits related to increased risk for cardiovascular diseases. Our results also may suggest CAPN5 as a candidate gene for metabolic syndrome.

CAPN10 UCSNP-43, UCSNP-19 and UCSNP-63 polymorphisms and metabolic syndrome in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder with individual susceptibility determined by genetic and environmental risk factors. Recently, studies have evaluated the CAPN10 gene in PCOS patients, suggesting that different alleles may play a role in PCOS susceptibility. We performed a cross-sectional study with 88 southern Brazilian hirsute patients with PCOS or idiopathic hirsutism (IH) to assess the influence of CAPN10 genetic variants on clinical and biochemical features of metabolic syndrome. PCOS patients were defined by oligo/amenorrheic cycles (<9 cycles/year), increased levels of serum testosterone and/or free androgen index, and exclusion of other disorders associated with hyperandrogenism. IH was diagnosed in hirsute patients with regular ovulatory cycles (luteal-phase progesterone levels >3.8 ng/ml), normal androgen levels, and without any known underlying disease (n = 29). Metabolic syndrome was defined according to the 2001 criteria of the National Cholesterol Education Program, Adult Treatment Panel III. UCSNP-43 polymorphism of CAPN10 was related to metabolic syndrome (p = 0.047) in PCOS; UCSNP-19 and UCSNP-63 were not associated with phenotypic traits in PCOS. These results provide evidence that CAPN10 gene UCSNP-43 polymorphisms may influence the PCOS metabolic phenotype. This should be further confirmed in large population-based studies.

Calpain facilitates actin reorganization during glucose-stimulated insulin secretion

Calpain-10 (CAPN10) has been identified as a diabetes susceptibility gene. Previous studies have shown that alterations in calpain activity alter both glucose uptake and insulin secretion. In this report, we investigated the role of calpain activity in the actin reorganization required for glucose-stimulated insulin secretion. In pancreatic INS-1 cells, acute exposure to a high glucose environment stimulated CAPN10 gene expression with a concomitant increase in calpain activity. However, high glucose did not significantly alter expression of the two major ubiquitously expressed calpain family members, CAPN1 and CAPN2. Furthermore, glucose stimulation resulted in the reorganization of actin and inhibition of calpain activity impaired this reorganization in INS-1 cells. Finally, we identified a 54 kDa isoform as the major CAPN10 isoform that associates with the actin cytoskeleton. Based on our findings, we propose that calpain plays a role in facilitating the actin reorganization required for glucose-stimulated insulin secretion in INS-1 cells.

Insulin, but not lipid availability, regulates calpain‐10 at the transcriptional level in human skeletal muscle

We investigated the molecular alterations underlying the reduction in carbohydrate (CHO) utilization with increased lipid availability in human skeletal muscle. On 2 occasions, 10 healthy young men [age 22 ± 1 (mean ± SEM), BMI 24 ± 1] underwent hyperinsulinemic (50 mU/m2/min) euglycemic (4.5 mM) clamps for 6h with (LIPID) and without (CON) intravenous intralipid (20% at a rate of 90 ml/h) plus heparin (200 U prime + 600 U/h) infusion. CHO and fat oxidation rates were determined by indirect calorimetry. Muscle biopsies were obtained before and after 3 and 6h of infusion for the determination of hexokinase II (HKII), pyruvate dehydrogenase kinase 4 (PDK4) and the diabetes linked gene calpain-10 (CAPN10) mRNA levels by real-time PCR. Lipid infusion increased fat oxidation after 90 min (P<0.05) and decreased CHO oxidation after 150 min (P<0.05) and glucose disposal after 210 min (P<0.05). At the end of the clamp, CHO disposal was ~50% lower in the LIPID compared to the CON trial (14.5 ± 0.7 vs 6.9 ± 0.8 mg/min/kg lean mass, P<0.001). CAPN10 mRNA levels decreased with insulin in both clamps (P<0.01) and were not affected by lipid infusion. HKII mRNA was upregulated 2-fold (P<0.01) in the CON trial, but this was impaired in the LIPID trial. PDK4 mRNA content was downregulated by 2-fold in response to insulin within 3 h in both clamps, and decreased further (6-fold, P<0.01) at 6 h in the CON but not the LIPID clamp. These results show that lipid-induced insulin resistance is associated with significant changes in genes regulating CHO utilisation. In contrast, it appears that insulin, and not lipid, regulates CAPN10 at the transcriptional level.

Polymorphisms of interleukin-6, hepatic lipase and calpain-10 genes, and preeclampsia

Objective We determined whether single nucleotide polymorphisms (SNPs) in interleukin-6 (IL-6), hepatic lipase (HL) and calpain-10 (CAPN-10) genes contribute to susceptibility to develop preeclampsia. Study design The study involved 133 preeclamptic and 115 healthy pregnant women who were genotyped for the C-174G polymorphism in the IL-6 gene, the G-250A polymorphism in the HL gene and SNP 43 (G/A) in the CAPN-10 gene. The χ 2-test was used to assess genotype and allele frequency differences between the preeclamptic and control groups. Results No significant differences were detected in genotype and allele distributions of the C-174G polymorphism in the IL-6 gene, between the preeclampsia and control groups ( p = 0.98 and 0.85, respectively). With respect to the G-250A polymorphism in the HL gene, the genotype and allele distributions were similar in both groups ( p = 0.64 and 0.48, respectively). The genotype and allele distributions of SNP 43 in the CAPN-10 gene also showed no statistical differences in the preeclampsia and control groups ( p = 0.73 and 0.45, respectively). Conclusions The C-174G polymorphism in the IL-6 gene, the G-250A polymorphism in the HL gene and SNP 43 (G/A) in the CAPN-10 gene are unlikely to be major genetic factors predisposing Finnish women to preeclampsia.

Calpain 10 and development of diabetes mellitus in cystic fibrosis

Diabetes mellitus (DM) and abnormal glucose tolerance (IGT) are common in cystic fibrosis (CF). The loss of pancreatic β-cells due to pancreatic fibrosis is thought to be one of the principal causes of diabetes in CF, but the aetiology of DM remains somewhat puzzling. Genetic factors may contribute to the development of CF related diabetes (CFRD). The purpose of this study was to investigate the role of polymorphisms in six genes on IGT or DM incidence. PCR and dHPLC were used to screen DNA samples for polymorphisms. Using 2-h oral glucose tolerance tests, 163 adult pancreatic insufficient CF patients have been subdivided in 3 groups: 54 NGT (normal glucose tolerance), 33 IGT and 76 CFRD. We found the first evidence for the association between CFRD and UCSNP-19 polymorphism in the CAPN10 gene. The UCSNP-19 genotype distribution differed significantly between NGT, IGT and CFRD groups. The difference reflected an increase in the 22 genotype (3 copies of 32-bp sequence) in IGT and CFRD patients ( p = 0.05). Odds ratio for the homozygote 22 versus homozygote 11 was 3.4 ( p = 0.02). All allele and genotype distributions for the other polymorphisms were similar in the three groups. In conclusion, our observations suggest that UCSNP-19 of CAPN10 may be involved in the pathogenesis of diabetes in CF.

Genetic Prediction of Future Type 2 Diabetes

BackgroundType 2 diabetes (T2D) is a multifactorial disease in which environmental triggers interact with genetic variants in the predisposition to the disease. A number of common variants have been associated with T2D but our knowledge of their ability to predict T2D prospectively is limited.Methods and FindingsBy using a Cox proportional hazard model, common variants in the PPARG (P12A), CAPN10 (SNP43 and 44), KCNJ11 (E23K), UCP2 (−866G>A), and IRS1 (G972R) genes were studied for their ability to predict T2D in 2,293 individuals participating in the Botnia study in Finland. After a median follow-up of 6 y, 132 (6%) persons developed T2D. The hazard ratio for risk of developing T2D was 1.7 (95% confidence interval [CI] 1.1–2.7) for the PPARG PP genotype, 1.5 (95% CI 1.0–2.2) for the CAPN10 SNP44 TT genotype, and 2.6 (95% CI 1.5–4.5) for the combination of PPARG and CAPN10 risk genotypes. In individuals with fasting plasma glucose ≥ 5.6 mmol/l and body mass index ≥ 30 kg/m2, the hazard ratio increased to 21.2 (95% CI 8.7–51.4) for the combination of the PPARG PP and CAPN10 SNP43/44 GG/TT genotypes as compared to those with the low-risk genotypes with normal fasting plasma glucose and body mass index < 30 kg/m2.ConclusionWe demonstrate in a large prospective study that variants in the PPARG and CAPN10 genes predict future T2D. Genetic testing might become a future approach to identify individuals at risk of developing T2D.

Genetic and Nongenetic Regulation of CAPN10 mRNA Expression in Skeletal Muscle

The gene encoding calpain-10 (CAPN10) has been identified as a candidate gene for type 2 diabetes. Our aim was to study the impact of genetic (heritability and polymorphisms) and nongenetic (insulin, free fatty acids, and age) factors on CAPN10 mRNA expression in skeletal muscle using two different study designs. Muscle biopsies were obtained before and after hyperinsulinemic-euglycemic clamps from 166 young and elderly monozygotic and dizygotic twins as well as from 15 subjects with normal (NGT) or impaired glucose tolerance (IGT) exposed to an Intralipid infusion. We found hereditary effects on both basal and insulin-exposed CAPN10 mRNA expression. Carriers of the type 2 diabetes-associated single nucleotide polymorphism (SNP)-43 G/G genotype had reduced CAPN10 mRNA levels compared with subjects carrying the SNP-43 A-allele. Age had no significant influence on CAPN10 mRNA levels. Insulin had no significant effect on CAPN10 mRNA levels, neither in the twins nor in the basal state of the Intralipid study. However, after a 24-h infusion of Intralipid, we noted a significant increase in CAPN10 mRNA in response to insulin in subjects with NGT but not in subjects with IGT. In conclusion, we provide evidence that mRNA expression of CAPN10 in skeletal muscle is under genetic control. Glucose-tolerant but not glucose-intolerant individuals upregulate their CAPN10 mRNA levels in response to prolonged exposure to fat.