Enzyme Kinetics Studies of Nucleoside Diphosphate Kinase in Human Erythrocytes and Frequency Distribution in Healthy Subjects and Transplant Recipients in Chinese Han Population

ABSTRACT Nucleoside diphosphate kinase (NDPK), as a house-keeping protein, involves in various molecular processes including signal transduction, energy and drug metabolism. The main objective was to investigate NDPK kinetics in human erythrocytes and to monitor the frequency distribution of NDPK activity levels in Chinese healthy subjects and transplant recipients. METHODS: NDPK activity in erythrocytes was detected by a validated ion-pair high-performance liquid chromatogram method. NDPK kinetics studies were carried out systematically. NDPK activity levels were determined in 500 healthy subjects, 250 kidney and 250 liver transplant recipients in Chinese Han population. RESULTS: Thermal and pH stability studies indicated NDPK was relatively stable at temperature 30-45ºC and pH 6.0-9.0. In substrate dependency study, the apparent Michaelis-Menten constant (K m ) and maximum velocity of enzymatic reaction (V max ) increased with concentration of substrates. Meanwhile, in product inhibition study, with the increasing concentration of dATP, the V max of dADP decreased with constant K m and K m of dGTP increased with constant V max . NDPK activity levels revealed a 7-fold variability and were not normally distributed in all groups. NDPK activity levels were significantly (P<0.05) higher in transplant group than those in health group. Additionally, much higher NDPK activity levels had been shown (P<0.001) in liver transplant recipients when compared to kidney transplant cases. CONCLUSIONS: NDPK kinetics studies indicated substrate dependency of NDPK and a "ping-pong" mechanism for production inhibition. Skewness distributions of NDPK activity levels were shown in the study population. The transplant recipients showed higher NDPK activity levels when compared to healthy subjects

A novel chimeric CYP11B2/CYP11B1 combined with a new p.L340P CYP11B1 mutation in a patient with 11OHD: case report

Abstract Background 11β-Hydroxylase deficiency (11OHD) is a common form of congenital adrenal hyperplasia that has been shown to result from inactivating CYP11B1 mutations, and pathogenic CYP11B2/CYP11B1 chimeras contribute to a minority of cases. Heterozygote cases (chimeras combined with missense mutation) are very rare, and genetic analysis of these cases is difficult. Case presentation We describe an 11OHD patient presenting with precocious pseudopuberty and hypokalemia hypertension who harbored a chimeric CYP11B2/CYP11B1 with a novel breakage point located at g.9559–9742 of CYP11B2. Interestingly, the other allele exhibited a new mutation, p.L340P, in CYP11B1. Bioinformatics and molecular dynamics simulation indicated that p.L340P decreased the stability and changed the surface configuration of 11β-hydroxylase, indicating a disease-causing mutation. Further pedigree study, PCR and next-generation sequencing indicated that the proband carried both the chimera and p.L340P, and coexistence of the two increased the severity of 11OHD in this family. After treatment with combined medications, blood pressure and clinical parameters improved. Conclusions Our results suggest that chimera screening and CYP11B1 mutation screening should be simultaneously conducted, and pedigree study is necessary

Additional file 4: of A novel chimeric CYP11B2/CYP11B1 combined with a new p.L340P CYP11B1 mutation in a patient with 11OHD: case report

Figure S2. The sequencing chromatogram near the mutation in the proband’s relatives. The box indicates the mutation location. (TIF 28380 kb

Additional file 2: of A novel chimeric CYP11B2/CYP11B1 combined with a new p.L340P CYP11B1 mutation in a patient with 11OHD: case report

Table S2. Bioinformatics analysis of the free energy alteration in CYP11B1mut (PDF 82 kb

Additional file 3: of A novel chimeric CYP11B2/CYP11B1 combined with a new p.L340P CYP11B1 mutation in a patient with 11OHD: case report

Figure S1. Graphs of sequence copy number around the mutation and multiple genes resulting in CAH of the proband and his mother by qPCR and targeted next-generation sequencing. (TIF 11910 kb

Additional file 1: of A novel chimeric CYP11B2/CYP11B1 combined with a new p.L340P CYP11B1 mutation in a patient with 11OHD: case report

Table S1. The laboratory and endocrinological evaluation of the proband pre- and post-treatment. (PDF 200 kb

Additional file 5: of A novel chimeric CYP11B2/CYP11B1 combined with a new p.L340P CYP11B1 mutation in a patient with 11OHD: case report

Figure S3. Radiation imaging of adrenal gland after treatment. A and B present abdominal CT images after treatment for 6 months showing that the sizes of the left and right adrenal gland are 75.2 mm × 22.1 mm and 67.3 mm × 38.7 mm, respectively. Similarly, C and D present abdominal CT images after treatment for 9 months showing that the sizes of the left and right adrenal gland are 65.2 mm × 24.4 mm and 63.7 mm × 35.7 mm, respectively. The arrow shows the bilateral adrenal lesions. (TIF 63145 kb

Additional file 6: of A novel chimeric CYP11B2/CYP11B1 combined with a new p.L340P CYP11B1 mutation in a patient with 11OHD: case report

Main methods used in the study. (DOC 112 kb

DPP-4 Inhibitors as Treatments for Type 1 Diabetes Mellitus: A Systematic Review and Meta-Analysis

Objective. Several clinical studies have reported the application of dipeptidyl peptidase-4 (DPP-4) inhibitors as treatments for type 1 diabetes mellitus (T1DM). This study aims to review the outcomes of these existing studies and to discuss the therapeutic effects of DPP-4 inhibitors on T1DM. Methods. We thoroughly searched the Medline, Embase, PubMed, and Cochrane Library databases and ClinicalTrials.gov for studies concerning the use of DPP-4 inhibitors in patients with T1DM. Results. In preclinical trials, DPP-4 inhibitors improved the pathogenesis of T1DM. However, only a portion of the studies showed potential efficacy regarding clinical glycemic control and other clinical parameters. From this meta-analysis, pooled data from 5 randomized controlled trials revealed that the additional use of DPP-4 inhibitors resulted in a greater decrease in glycated hemoglobin A1c (HbA1c) levels (0.07%, 95% CI (−0.37%–0.23%)) than insulin monotherapy, although the decrease was not significant. A small decrease in postprandial glucose or insulin consumption was confirmed. Conclusion. Although DPP-4 inhibitors may be beneficial for T1DM, existing studies do not strongly support these positive effects in clinical practice. Further optimized clinical trials are needed

Plasma Asprosin Levels Are Associated with Glucose Metabolism, Lipid, and Sex Hormone Profiles in Females with Metabolic-Related Diseases

Asprosin is a white adipose tissue-derived hormone that increases abnormally in mammals with insulin resistance. However, the role of asprosin in polycystic ovary syndrome (PCOS), a disease partly characterized by insulin resistance, and its potential connection with type 2 diabetes mellitus (T2DM) and PCOS has not been thoroughly elucidated to date. To investigate the association of asprosin with metabolic profiles, sex-related hormones, or inflammation in females with T2DM or PCOS, plasma asprosin and metabolic indicators were measured in 66 healthy females, 53 female patients with T2DM, and 41 patients with PCOS. Spearman’s correlation analysis and binary logistic regression analysis models were used. Plasma asprosin was significantly higher in T2DM females than in healthy subjects (P<0.001) and was positively correlated with fasting blood glucose (FBG), hemoglobin A1c (HbA1c), and HOMA-IR (P<0.05). Asprosin in PCOS subjects was also higher than in healthy subjects (P<0.001) but lower than in T2DM subjects (P<0.05), and it was positively correlated with FBG, HbA1c, HOMA-IR, LDL-c, APOB, APOE, and testosterone (P<0.05). The BMI-categorized subgroups of PCOS subjects also showed correlations of asprosin with metabolic profiles and sex-related hormones. Binary logistic regression analysis revealed that plasma asprosin level acted as an independent risk factor for T2DM or PCOS. These findings suggest the correlation of plasma asprosin level with glucose metabolism, lipid metabolism, sex-related hormones, and inflammation in females, supporting asprosin as a potential predictive factor for females with metabolic-related diseases. This trial is registered with ChiCTR-ROC-17010719