Hepatitis B virus reactivation with corticosteroid therapy in patients with adrenal insufficiency.

OBJECTIVE: Whether or not reactivation of hepatitis B virus (HBV) might occur during corticosteroid therapy in hepatitis B surface antigen (HBsAg)-negative patients with adrenal insufficiency was investigated. PATIENTS AND METHODS: We consecutively enrolled 66 patients with adrenal insufficiency undergoing physiological corticosteroid replacement therapy at Saitama Medical University Hospital between June 2013 and June 2014, and 220 patients with rheumatic disease receiving a pharmacologic dose of corticosteroids served as the positive control group. The latter group was separated into 101 patients treated only with corticosteroids, and 119 patients given corticosteroids plus immunosuppressants and/or disease-modifying antirheumatic drugs (DMARDs). HBsAg and antibody (Ab) levels against HBs, and hepatitis B core (HBc) were determined in all the patients. In patients with positive HBsAb and/or HBcAb, real-time PCR was performed for HBV-DNA. The incidence rates of conversion to HBV-DNA-positive status were evaluated. RESULTS: Hepatitis B virus reactivation occurred in six patients with rheumatic disease, three of whom were receiving a pharmacological dose of corticosteroids only, and three who were receiving corticosteroids with immunosuppressants and/or DMARDs. However, no reactivation occurred in patients receiving corticosteroid replacements for adrenal insufficiency. Maintenance and maximum corticosteroid doses administered to patients with rheumatic disease were significantly greater than those in patients with adrenal insufficiency. CONCLUSION: These results suggest that, although corticosteroid replacement therapy for adrenal insufficiency might be safe with respect to HBV reactivation, attention should be paid to HBV reactivation during corticosteroid therapy in rheumatic disease patients, since the dose of corticosteroids administered is usually large, and since other immunosuppressants are co-administered.

Intrinsic insulin secretion capacity might be preserved by discontinuing anti-programmed cell death protein 1 antibody treatment in 'anti-programmed cell death protein 1 antibody-induced' fulminant type 1 diabetes.

Intrinsic insulin secretion capacity may be preserved by discontinuing anti-PD-1 antibody treatment in 'anti-PD-1 antibody-induced'fulminant type 1 diabetes.

Clinical features and therapeutic perspectives on hypertension in diabetics.

Over 50% of patients with diabetes mellitus, either type 1 or 2, ultimately develop hypertension as a complication. In diabetics, this further increases the incidence of cardiovascular disease (CVD) by 2- to 3-fold and accelerates the progression of diabetic nephropathy. Arteriosclerosis, a clinical feature of hypertension in diabetics, develops and advances from a young age. Therefore, in providing treatment, it is necessary to evaluate the degree of arteriosclerosis. Diabetic patients are encouraged to strictly control their blood glucose levels. Recently developed drugs, such as GLP-1 receptor agonists, DPP-4 inhibitors and SGLT2 inhibitors, also have hypotensive actions, making them ideal for use in diabetics with hypertension. SGLT2 inhibitors and GLP-1 receptor agonists reportedly suppress the onset and progression of CVD, as well as diabetic nephropathy. The possibility of hypoglycemia triggering blood pressure elevation and arrhythmia has been noted, so a key point here is not to cause hypoglycemia. In selecting hypotensive agents, we must choose types that do not aggravate insulin resistance and engage in hypotensive treatment that also considers both nocturnal and morning hypertension. In addition, facing the onset of an aging society, there is a growing need for treatments that do not cause excessive blood pressure reduction or hypoglycemia. Favorable lifelong blood pressure and glucose control are increasingly important for the treatment of diabetes accompanied by hypertension.

The renoprotective effect and safety of a DPP-4 inhibitor, sitagliptin, at a small dose in type 2 diabetic patients with a renal dysfunction when changed from other DPP-4 inhibitors: REAL trial.

BACKGROUND: We conducted the multicenter, prospective, open-label study in type 2 diabetic (T2DM) patients with renal dysfunction, to clarify the efficacy and the safety in relation to renal function and glycemic control, and the economic effect when other dipeptidyl peptidase-4 (DPP-4) inhibitors were switched to a small dose of sitagliptin depending on their renal function. METHODS: Vildagliptin, alogliptin, or linagliptin received for more than 2 months were changed to sitagliptin at 25 or 12.5 mg/day depending on their renal function in 49 T2DMs. Renal function and glycemic control, and the drug cost were assessed during 6 months. RESULTS: Estimated glomerular filtration rate was not changed in patients not on hemodialysis (n = 29). The HbA1c levels were not altered in all of the patients including those on hemodialysis (n = 20). The active glucagon-like peptide-1 levels or other renal parameters were not altered significantly. There were no adverse events to be related to the drugs. The daily drug expense was reduced by 88.1 yen per patient. CONCLUSION: Switching to a small dose of sitagliptin according to the renal function in T2DM patients with renal dysfunction demonstrated the same efficacy and safety as those with other full-dose DPP-4 inhibitors, indicating a therapeutic option with a high cost performance.

Effects of the Activation of Three Major Hepatic Akt Substrates on Glucose Metabolism in Male Mice.

Insulin suppresses glucose output from the liver via Akt activation; however, which substrate of Akt plays the major role in transducing this effect is unclear. We tested the postnatal expression of Akt-unresponsive, constitutively active mutants of three major Akt substrates widely considered to regulate glucose metabolism [i.e., FoxO1, PGC1α, and glycogen synthase kinase-3ß (GSK3ß)] using adenoviral gene delivery to the mouse liver. We performed physiological hyperinsulinemic-euglycemic clamp studies using these mice under awake and nonrestrained conditions with blood sampling via an arterial catheter. Hepatic expression of constitutively active FoxO1 induced significant hepatic and systemic insulin resistance. However, neither the expression of constitutively active PGC1α nor that of GSK3ß significantly changed insulin sensitivity. Simultaneous expression of all three mutants together induced no further insulin resistance compared with that of the FoxO1 mutant. The glycogen content in the liver was significantly reduced by constitutively active GSK3ß expression. In cultured hepatocytes, constitutively active PGC1α induced markedly stronger transcriptional enhancement of gluconeogenic key enzymes than did constitutively active FoxO1. From these results, we conclude that FoxO1 has the most prominent role in transducing insulin's effect downstream from Akt to suppress hepatic glucose output, involving mechanisms independent of the transcriptional regulation of key gluconeogenic enzymes.

Effect of antihyperglycemic drug monotherapy to prevent the progression of mild hyperglycemia in early type 2 diabetic patients: the Japan Early Diabetes Intervention Study (JEDIS).

To effectively prevent the worsening of hyperglycemia in type 2 diabetes mellitus, it is of interest to see the clinical efficacy of early introduction of pharmacotherapy in addition to lifestyle intervention which is not always easy to continue throughout life. This is a randomized unblinded comparative clinical study on suppressive effects of lifestyle intervention alone and additional monotherapies for mild hyperglycemia at an early stage of treatment-naïve type 2 diabetic patients, whose fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1c) are less than 140 mg/dl and 7.4%, respectively. The control group (group N = arm N) received conventional lifestyle intervention assisted by routine facilities, while the pharmacological intervention group (group D composed of 4 arms) was additionally treated by monotherapy with one of four kinds of oral antihyperglycemic agents i.e., sulfonylurea (SU), α-glucosidase inhibitor, biguanide and dipeptidyl peptidase-4 inhibitor. The participants were scheduled to follow up for 3 years to maintain glycemic control below primary endpoint which was defined as the first occurrence of FPG ≥140 mg/dl and HbA1c ≥7.4% simultaneously even by increasing doses of oral drug in group D, if necessary. The outcomes of occurrences of primary endpoint were not different between group N and group D composed of 4 arms during 3 years by Kaplan-Meyer plots (p = 0.405). On the other hand, ΔFPG (Δ: incremental change from baseline) and ΔHbA1c in group D significantly decreased when compared to those of group N during 3 years (p < 0.05 and p < 0.01 respectively). Significant reductions of ΔBMI were seen similarly in both groups throughout the study (p < 0.05), but did not differ between two groups. Among these 5 arms, significant decreases of ΔHbA1c were observed in three monotherapy arms of group D compared to arm N for 3 years (p < 0.05 or p < 0.01), except for arm SU in which ΔBMI and ΔHbA1c tended to increase at the latter half of the study. The final achievement rates of target HbA1c less than 7.4, 7.0 and 6.5% in all the participants tended to be higher in group D than in group N (p < 0.047 for 7.4%, but not significant for others). In conclusion, the early introduction of pharmacological monotherapy in addition to lifestyle intervention seem to suppress mild hyperglycemia with small doses of antihyperglycemic agents for 3 years, except for the use of SU drug. Although a larger scale of trial will be necessary to conclude, the early treatment with suitable monotherapy could be effective to bring and keep "safe level of glycemia".

Erratum to: Decreased glucagon levels and decreased insulin secretion after sitagliptin versus mitiglinide administration with similar glycemic levels following an oral glucose load: a randomized crossover pharmaceutical mechanistic study.

[This corrects the article DOI: 10.1007/s13340-015-0207-1.].

A randomized controlled study of finerenone versus placebo in Japanese patients with type 2 diabetes mellitus and diabetic nephropathy.

AIMS: Finerenone (BAY 94-8862) is a novel non-steroidal mineralocorticoid receptor antagonist. The aim of this study was to compare the efficacy and safety of seven once-daily oral doses of finerenone (1.25-20mg) and placebo in 96 patients with type 2 diabetes mellitus (T2DM) and diabetic nephropathy (DN) receiving a RAS blocker. METHODS: ARTS-DN Japan was a multicenter, randomized, double-blind, placebo-controlled, phase 2b study. RESULTS: Analysis of the urinary albumin-to-creatinine ratio (UACR) at day 90 relative to baseline indicated a nominally significant effect of finerenone. The UACR at day 90 relative to baseline for each finerenone treatment group was numerically reduced compared with placebo. No serious adverse events (AEs) or deaths were reported and no patients experienced treatment-emergent AEs resulting in discontinuation of study drug. Small mean increases in serum potassium level were observed in the finerenone treatment groups (0.025-0.167mmol/L) compared with the placebo group (-0.075mmol/L); no patients developed hyperkalemia. CONCLUSION: When given in addition to a RAS inhibitor, finerenone reduced albuminuria without adverse effects on serum potassium levels or renal function in Japanese patients with T2DM and DN.

Patients with type 2 diabetes having higher glomerular filtration rate showed rapid renal function decline followed by impaired glomerular filtration rate: Japan Diabetes Complications Study.

AIMS: The Japan Diabetes Complications Study (JDCS), a nation-wide, multicenter, prospective study of patients with type 2 diabetes, reported that hemoglobin A1c (HbA1c), systolic blood pressure, and smoking were risk factors for the onset of macroalbuminuria. This study explored the risk factors for glomerular filtration rate (GFR) decline in the JDCS patients. METHODS: We examined the 1407 JDCS patients (667 women, mean age 59years, 974 normoalbuminuria, 433 microalbuminuria) whose urinary albumin-to-creatinine ratio (UACR) and estimated GFR (eGFR) were determined at baseline with an 8-year follow-up. We divided all the patients into four groups according to baseline eGFR: G1 (120≤eGFR), G2 (90≤eGFR<120), G3 (60≤eGFR<90), G4 (eGFR<60). RESULTS: The eGFRs in groups G1 and G2 decreased at follow-up compared to those at the baseline. The risk of annual eGFR decline rate≥3ml/min/1.73m2 (rapid decliners) increased as the baseline eGFR increased. Advanced age, high HbA1c, and UACR, or diabetic retinopathy at baseline were risk factors for the rapid decliners. Especially the G1 group had a significant risk for the rapid decliners. The frequency of the patients with GFR<60ml/min/1.73m2 at the follow-up amounted to 31.1% in the rapid decliners, which was higher than 12% in the non-rapid decliners. CONCLUSIONS: In normo- and microalbuminuric patients with type 2 diabetes, extra careful attention should be paid to patients with eGFR ≥120ml/min/1.73m2 to detect cases with rapidly decreased GFR under the normal range.

Feminizing Adrenocortical Carcinoma with Distinct Histopathological Findings.

We herein present a 60-year-old man with adrenocortical carcinoma who had gynecomastia. An endocrinological examination revealed increased levels of serum estradiol and dehydroepiandrosterone-sulfate (DHEA-S) and reduced levels of free testosterone. Magnetic resonance imaging showed an adrenal tumor with heterogeneous intensity. Iodine-131 adosterol scintigraphy showed an increased uptake at the same site. Because feminizing adrenocortical carcinoma was suspected, right adrenalectomy was performed; the pathological diagnosis was adrenocortical carcinoma. The results of immunostaining indicated a virilizing tumor. Aromatase activity was identified on RT-PCR. As disorganized steroidogenesis is pathologically present in adrenocortical carcinoma, this diagnosis should be made with caution.

Ezetimibe Promotes Brush Border Membrane-to-Lumen Cholesterol Efflux in the Small Intestine.

Ezetimibe inhibits Niemann-Pick C1-like 1 (NPC1L1), an apical membrane cholesterol transporter of enterocytes, thereby reduces intestinal cholesterol absorption. This treatment also increases extrahepatic reverse cholesterol transport via an undefined mechanism. To explore this, we employed a trans-intestinal cholesterol efflux (TICE) assay, which directly detects circulation-to-intestinal lumen 3H-cholesterol transit in a cannulated jejunal segment, and found an increase of TICE by 45%. To examine whether such increase in efflux occurs at the intestinal brush border membrane(BBM)-level, we performed luminal perfusion assays, similar to TICE but the jejunal wall was labelled with orally-given 3H-cholesterol, and determined elevated BBM-to-lumen cholesterol efflux by 3.5-fold with ezetimibe. Such increased efflux probably promotes circulation-to-lumen cholesterol transit eventually; thus increases TICE. Next, we wondered how inhibition of NPC1L1, an influx transporter, resulted in increased efflux. When we traced orally-given 3H-cholesterol in mice, we found that lumen-to-BBM 3H-cholesterol transit was rapid and less sensitive to ezetimibe treatment. Comparison of the efflux and fractional cholesterol absorption revealed an inverse correlation, indicating the efflux as an opposite-regulatory factor for cholesterol absorption efficiency and counteracting to the naturally-occurring rapid cholesterol influx to the BBM. These suggest that the ezetimibe-stimulated increased efflux is crucial in reducing cholesterol absorption. Ezetimibe-induced increase in cholesterol efflux was approximately 2.5-fold greater in mice having endogenous ATP-binding cassette G5/G8 heterodimer, the major sterol efflux transporter of enterocytes, than the knockout counterparts, suggesting that the heterodimer confers additional rapid BBM-to-lumen cholesterol efflux in response to NPC1L1 inhibition. The observed framework for intestinal cholesterol fluxes may provide ways to modulate the flux to dispose of endogenous cholesterol efficiently for therapeutic purposes.

Maximum BMI and microvascular complications in a cohort of Japanese patients with type 2 diabetes: the Japan Diabetes Complications Study.

AIMS: The aim of this study was to examine the associations between possible indices of obesity based on information on weight history and the incidence of microvascular complications. METHODS: A cohort of individuals with type 2 diabetes from 59 institutes in Japan was followed for 8years. Patients were classified into three categories according to weight at entrance and past maximum weight: normal (BMI at baseline <25kg/m(2) and maximum BMI <25kg/m(2)), past obesity (BMI at baseline <25kg/m(2) and maximum BMI ≥25kg/m(2)), and current obesity (BMI at baseline ≥25kg/m(2)) groups. The outcomes were diabetic retinopathy and overt nephropathy. RESULTS: BMI at maximum and baseline of the 1809 patients was 26.5±3.5 and 23.1±3.0kg/m(2) (p<0.01), respectively (23.0±1.6 and 20.6±1.9kg/m(2) for normal, 27.4±2.0 and 22.8±1.4kg/m(2) for past obesity, and 30.1±2.9 and 27.0±1.8kg/m(2) for current obesity). The hazard ratios of past and current obesity compared to normal were 1.92 (95% CI, 1.08-3.41; p=0.03) and 2.21 (1.16-4.22; p=0.02), respectively, for overt nephropathy and 1.38 (1.05-1.83; p=0.02) and 1.64 (1.18-2.28; p<0.01), respectively, for diabetic retinopathy after adjustment for confounders. CONCLUSIONS: Past obesity as well as current obesity were associated with increased risks of microvascular complications. Further identification of high-risk populations may be possible by classifying normal weight patients by past obesity.

Decreased glucagon levels and decreased insulin secretion after sitagliptin versus mitiglinide administration with similar glycemic levels following an oral glucose load: a randomized crossover pharmaceutical mechanistic study.

AIMS: Both sitagliptin (SIT) and mitiglinide (MIT) can lower postprandial hyperglycemia. The purpose of this study was to examine differences in insulin and glucagon secretion after SIT or MIT administration when similar levels of plasma glucose (PG) were achieved for both agents following an oral glucose load. PATIENTS AND METHODS: We directly compared the effects of these two agents in 16 type-2 diabetic patients (M/F = 10/6, age 66 ± 3 years old, HbA1c 6.6 ± 0.5 %). Patients received SIT (50 mg qd for 1 week and 100 mg qd for an additional week) or MIT (10 mg tid for 2 weeks). After 2 weeks, patients crossed over to the other treatment. 75-g oral glucose tolerance tests were conducted before the study and after interventions. RESULTS: The area under the curve (AUC) up to 180 min for the PG response was similar for both agents. While basal insulin secretion rates (ISR) were similar, incremental AUC of ISR was significantly lower in the SIT treatment (522 ± 108 vs 702 ± 288 pmol/min min, p < 0.01), although the difference between the SIT and MIT treatments in the Matsuda index-which reflects insulin sensitivity-remained nonsignificant. Glucose-stimulated insulin secretion was similarly increased by the MIT and SIT treatments. Suppression of the AUC for glucagon was observed in the SIT treatment, while MIT treatment failed to suppress the glucagon concentration (-432 ± 2322 vs MIT 1116 ± 2520 pg/ml min, p < 0.05). The basal proinsulin/insulin ratio was lower in the SIT treatment (0.23 ± 0.04 vs MIT 0.26 ± 0.36, p < 0.05). CONCLUSIONS: Although either SIT or MIT can be employed to reduce postprandial hyperglycemia, SIT induces changes in hormonal profiles that are more favorable to islet functions than MIT does.

Efficacy and Clinical Characteristics of Liraglutide in Japanese Patients With Type 2 Diabetes.

BACKGROUND: Liraglutide was first released in Japan as a long-acting once-daily glucagon-like peptide-1 receptor agonist. The maximum dose in Japan is 0.9 mg/day, which is half of that used in the United States and the European Union (1.8 mg/day). The efficacy of this maximum allowable dose of liraglutide for Japanese patients and the profiles of those patients for whom this agent should be recommended remain unclear. METHODS: This study aimed to examine the effective use of liraglutide in Japanese type 2 diabetic patients. We administered liraglutide to 60 patients, who had been managed with oral hypoglycemic agents or diet and exercise therapy only, during a period of 6 months. RESULTS: Though HbA1c levels significantly decreased, by approximately 1.5%, after 6 months of liraglutide administration, no significant changes in body weights were observed. The 0.6 mg dose was effective in approximately 40% of patients. In contrast, the effects of a dose increase from 0.6 mg to 0.9 mg were small. The greatest efficacy, as shown by a 2.5% HbA1c decrease, was achieved in non-obese patients. Thus, efficacy decreased as the degree of obesity increased. In addition, efficacy was higher in patients who had a diabetes duration of less than 10 years and was also higher in the group that had a low sulfonylurea (SU) index, when we define the SU index as mg/glimepiride × years of treatment. CONCLUSIONS: As appetite suppressions and associated decreases in body weights were not observed in obese patients, the efficacy of liraglutide at 0.9 mg did not appear to be high. Rather, it appeared to be highly effective for patients who were non-obese and for whom amelioration of blood glucose elevations could be anticipated via the stimulation of insulin secretion. Therefore, we found that liraglutide at doses of 0.9 mg was highly effective in non-obese patients who were in the early stages of diabetes and was particularly effective in patients who had not yet been administered SU agents.

Preferable effects of olmesartan/calcium channel blocker to olmesartan/diuretic on blood pressure variability in very elderly hypertension: COLM study subanalysis.

OBJECTIVE: The aims of this subanalysis of the COLM trial [NCT00454662] were to compare visit-to-visit variability (VVV) of blood pressure (BP) between age groups and between two treatment combinations, that is, the angiotensin II receptor blocker, olmesartan combined with a calcium channel blocker (CCB), or a diuretic and to investigate the effect of VVV of BP on cardiovascular events in elderly hypertensive patients. METHODS: Hypertensive patients ages 65-84 years with a history of and/or risk factors for cardiovascular disease were randomized to receive treatment with olmesartan along with either a CCB or a diuretic for at least 3 years. This subanalysis comprised 4876 patients who had their office BP measured at least three occasions (median nine occasions) during the follow-up period. VVV of BP was defined by several metrics including the within-individual standard deviation of every visit during the follow-up period. RESULTS: VVV of SBP was larger in the very elderly group (75-84 years) than in the elderly group (65-74 years). VVV of SBP was smaller in the olmesartan along with CCB group than in the olmesartan along with diuretic group, especially in very elderly patients and also isolated systolic hypertensive patients. The incidence rate of primary endpoint increased along with an increment in the SD of SBP in all of the age and treatment groups. CONCLUSION: VVV of SBP may mediate the preferable effect of combination of angiotensin II receptor blocker along with CCB on cardiovascular events in the very elderly and also isolated systolic hypertensive patients.

Influence of Treatment with Extracts of Hypsyzigus marmoreus Mushroom on Body Composition during Obesity Development in KK-A(y) Mice.

Hypsyzigus marmoreus (HM), an edible mushroom, has several effects, including antitumor, antioxidant and anti-allergy properties. On the other hand, the possibly useful effect of HM in diabetic mice has not as yet been elucidated. In this study, we showed treatment with a water soluble extract from HM (EHM) to reduce fat deposits without affecting body weight loss in KK-A(y) mice. EHM treatment also abolished the expressions of pro-inflammatory adipokines, such as tumor necrosis factor α and monocyte chemoattractant protein 1, as compared with vehicle treatment. The expressions of uncoupling protein 3 and peroxisome proliferator-activated receptor gamma coactivator 1α in the soleus muscles of EHM treatment groups were significantly elevated as compared to those in vehicle-treated muscle tissues. These results raise the possibility that EHM can regulate both obesity and insulin resistance.

The efficacy of vildagliptin concomitant with insulin therapy in type 2 diabetic subjects.

BACKGROUND: In Japan, dipeptidyl peptidase 4 (DPP4) inhibitors have become standard therapeutic agents for type 2 diabetes, and numbers of patients receiving insulin therapy combined with DPP4 inhibitors, which is a highly effective regimen, are increasing. METHODS: In this study, we evaluated the efficacy of vildagliptin administered at the dose of 100 mg twice daily in 57 patients with type 2 diabetes already receiving insulin treatment. RESULTS: The 36 patients who simply received add-on vildagliptin showed a 0.6% decrease in HbA1c levels, despite a marked insulin dose reduction, mainly bolus insulin, of approximately 8.3 units. In addition, body mass index exhibited a significant negative correlation with the efficacy of vildagliptin, i.e., ΔHbA1c. On the other hand, the 21 patients switched from 50 mg of sitagliptin to vildagliptin showed HbA1c decreases approaching 0.7%. CONCLUSION: Taking into consideration that twice-daily oral vildagliptin has already been reported to be advantageous in reducing postprandial hyperglycemia, this drug was suggested to be more effective in reducing HbA1c than sitagliptin under conditions in which it is used as a supplement to basal insulin, as in this study.

A genome-wide association study for diabetic retinopathy in a Japanese population: potential association with a long intergenic non-coding RNA.

Elucidation of the genetic susceptibility factors for diabetic retinopathy (DR) is important to gain insight into the pathogenesis of DR, and may help to define genetic risk factors for this condition. In the present study, we conducted a three-stage genome-wide association study (GWAS) to identify DR susceptibility loci in Japanese patients, which comprised a total of 837 type 2 diabetes patients with DR (cases) and 1,149 without DR (controls). From the stage 1 genome-wide scan of 446 subjects (205 cases and 241 controls) on 614,216 SNPs, 249 SNPs were selected for the stage 2 replication in 623 subjects (335 cases and 288 controls). Eight SNPs were further followed up in a stage 3 study of 297 cases and 620 controls. The top signal from the present association analysis was rs9362054 in an intron of RP1-90L14.1 showing borderline genome-wide significance (Pmet = 1.4×10(-7), meta-analysis of stage 1 and stage 2, allele model). RP1-90L14.1 is a long intergenic non-coding RNA (lincRNA) adjacent to KIAA1009/QN1/CEP162 gene; CEP162 plays a critical role in ciliary transition zone formation before ciliogenesis. The present study raises the possibility that the dysregulation of ciliary-associated genes plays a role in susceptibility to DR.

Identification of two nickel ion-induced genes, NCI16 and PcGST1, in Paramecium caudatum.

Here, we describe the isolation of two nickel-induced genes in Paramecium caudatum, NCI16 and PcGST1, by subtractive hybridization. NCI16 encoded a predicted four-transmembrane domain protein (∼16 kDa) of unknown function, and PcGST1 encoded glutathione S-transferase (GST; ∼25 kDa) with GST and glutathione peroxidase (GPx) activities. Exposing cells to cobalt chloride also caused the moderate upregulation of NCI16 and PcGST1 mRNAs. Both nickel sulfate and cobalt chloride dose dependently induced NCI16 and PcGST1 mRNAs, but with different profiles. Nickel treatment caused a continuous increase in PcGST1 and NCI16 mRNA levels for up to 3 and 6 days, respectively, and a notable increase in H2O2 concentrations in P. caudatum. NCI16 expression was significantly enhanced by incubating cells with H2O2, implying that NCI16 induction in the presence of nickel ions is caused by reactive oxygen species (ROS). On the other hand, PcGST1 was highly induced by the antioxidant tert-butylhydroquinone (tBHQ) but not by H2O2, suggesting that different mechanisms mediate the induction of NCI16 and PcGST1. We introduced a luciferase reporter vector with an ∼0.42-kb putative PcGST1 promoter into cells and then exposed the transformants to nickel sulfate. This resulted in significant luciferase upregulation, indicating that the putative PcGST1 promoter contains a nickel-responsive element. Our nickel-inducible system also may be applicable to the efficient expression of proteins that are toxic to host cells or require temporal control.