In Silico Study of Rett Syndrome Treatment-Related Genes, MECP2, CDKL5, and FOXG1, by Evolutionary Classification and Disordered Region Assessment

Rett syndrome (RTT), a neurodevelopmental disorder, is mainly caused by mutations in methyl CpG-binding protein 2 (MECP2), which has multiple functions such as binding to methylated DNA or interacting with a transcriptional co-repressor complex. It has been established that alterations in cyclin-dependent kinase-like 5 (CDKL5) or forkhead box protein G1 (FOXG1) correspond to distinct neurodevelopmental disorders, given that a series of studies have indicated that RTT is also caused by alterations in either one of these genes. We investigated the evolution and molecular features of MeCP2, CDKL5, and FOXG1 and their binding partners using phylogenetic profiling to gain a better understanding of their similarities. We also predicted the structural order–disorder propensity and assessed the evolutionary rates per site of MeCP2, CDKL5, and FOXG1 to investigate the relationships between disordered structure and other related properties with RTT. Here, we provide insight to the structural characteristics, evolution and interaction landscapes of those three proteins. We also uncovered the disordered structure properties and evolution of those proteins which may provide valuable information for the development of therapeutic strategies of RTT

Cbl-b Positively Regulates Btk-mediated Activation of Phospholipase C-γ2 in B Cells

Genetic studies have revealed that Cbl-b plays a negative role in the antigen receptor–mediated proliferation of lymphocytes. However, we show that Cbl-b–deficient DT40 B cells display reduced phospholipase C (PLC)-γ2 activation and Ca2+ mobilization upon B cell receptor (BCR) stimulation. In addition, the overexpression of Cbl-b in WEHI-231 mouse B cells resulted in the augmentation of BCR-induced Ca2+ mobilization. Cbl-b interacted with PLC-γ2 and helped the association of PLC-γ2 with Bruton's tyrosine kinase (Btk), as well as B cell linker protein (BLNK). Cbl-b was indispensable for Btk-dependent sustained increase in intracellular Ca2+. Both NH2-terminal tyrosine kinase-binding domain and COOH-terminal half region of Cbl-b were essential for its association with PLC-γ2 and the regulation of Ca2+ mobilization. These results demonstrate that Cbl-b positively regulates BCR-mediated Ca2+ signaling, most likely by influencing the Btk/BLNK/PLC-γ2 complex formation

A Novel PHEX Mutation in Japanese Patients with X-Linked Hypophosphatemic Rickets

X-linked hypophosphatemic rickets (XLH) is a dominant inherited disorder characterized by renal phosphate wasting, aberrant vitamin D metabolism, and abnormal bone mineralization. Inactivating mutations in the gene encoding phosphate-regulating gene with homologies to endopeptidases on the X chromosome (PHEX) have been found to be associated with XLH. Here, we report a 16-year-old female patient affected by hypophosphatemic rickets. We evaluated her serum fibroblast growth factor 23 (FGF23) levels and conducted sequence analysis of the disease-associated genes of FGF23-related hypophosphatemic rickets: PHEX, FGF23, dentin matrix protein 1, and ectonucleotide pyrophosphatase/phosphodiesterase 1. She was diagnosed with XLH based on her clinical features and family history. Additionally, we observed elevated FGF23 levels and a novel PHEX exon 9 mutation (c.947G>T; p.Gly316Val) inherited from her father. Although bioinformatics showed that the mutation was neutral, Gly316 is perfectly conserved among humans, mice, and rats, and there were no mutations in other FGF23-related rickets genes, suggesting that in silico analysis is limited in determining mutation pathogenicity. In summary, we present a female patient and her father with XLH harboring a novel PHEX mutation that appears to be causative of disease. Measurement of FGF23 for hypophosphatemic patients is therefore useful for the diagnosis of FGF23-dependent hypophosphatemia

Cyclin-Dependent Kinase-Like 5 (CDKL5): Possible Cellular Signalling Targets and Involvement in CDKL5 Deficiency Disorder

Cyclin-dependent kinase-like 5 (CDKL5, also known as STK9) is a serine/threonine protein kinase originally identified in 1998 during a transcriptional mapping project of the human X chromosome. Thereafter, a mutation in CDKL5 was reported in individuals with the atypical Rett syndrome, a neurodevelopmental disorder, suggesting that CDKL5 plays an important regulatory role in neuronal function. The disease associated with CDKL5 mutation has recently been recognised as CDKL5 deficiency disorder (CDD) and has been distinguished from the Rett syndrome owing to its symptomatic manifestation. Because CDKL5 mutations identified in patients with CDD cause enzymatic loss of function, CDKL5 catalytic activity is likely strongly associated with the disease. Consequently, the exploration of CDKL5 substrate characteristics and regulatory mechanisms of its catalytic activity are important for identifying therapeutic target molecules and developing new treatment. In this review, we summarise recent findings on the phosphorylation of CDKL5 substrates and the mechanisms of CDKL5 phosphorylation and dephosphorylation. We also discuss the relationship between changes in the phosphorylation signalling pathways and the Cdkl5 knockout mouse phenotype and consider future prospects for the treatment of mental and neurological disease associated with CDKL5 mutations

The risk of diabetes incidence based on the baseline HbA1c levels after the stratification of major risk factor in the Cox proportional-hazard model.

<p>Values are expressed as adjusted hazard ratios (95% confidence intervals) calculated by Cox proportional-hazard models.</p><p>The analyses were adjusted by age, sex, BMI, hypertension, family history of diabetes, exercise habit, smoking habit, and heavy alcohol consumption except each factor of stratification.</p><p>The risk of diabetes incidence based on the baseline HbA1c levels after the stratification of major risk factor in the Cox proportional-hazard model.</p

Characteristics of the studies which evaluated the incidence of type 2 diabetes using baseline HbA_1c levels.

<p>* Median age</p><p>^† This study advocated that it was a prospective cohort, but it was a part of a randomized clinical trial.</p><p>^‡ Race was not listed, but almost 100% of participants might be Japanese.</p><p>^§ Mean age was not listed, but 15–39yr., 40–59yr., and ≥59yr. were 24, 32, 44%, respectively.</p><p>FPG: fasting plasma glucose; CPG: casual plasma glucose</p><p>Characteristics of the studies which evaluated the incidence of type 2 diabetes using baseline HbA_1c levels.</p

Incidence of Type 2 Diabetes in Pre-Diabetic Japanese Individuals Categorized by HbA_1c Levels: A Historical Cohort Study

<div><p>Objective</p><p>Reported incidence of type 2 diabetes estimated at the pre-diabetic stage differs widely (2.3–18.1% per year). Because clinicians need to know the risk of incident diabetes after a diagnosis of pre-diabetes, our objective was to estimate precise incidence of diabetes using baseline HbA_1c levels.</p><p>Methods</p><p>A historical cohort study using electronic medical record data obtained between January 2008 and December 2013. A total of 52,781 individuals with HbA_1c < 6.5% were assigned to one of six groups categorized by baseline HbA_1c level: ≤ 5.5% (n=34,616), 5.6–5.7% (n=9,388), 5.8–5.9% (n=4,664), 6.0–6.1% (n= 2,338), 6.2–6.3% (n=1,257), and 6.4% (n=518). Participants were tracked until a subsequent diagnosis of diabetes or end of follow-up during a period of 5 years.</p><p>Results</p><p>During the follow-up period (mean 3.7 years), 4,369 participants developed diabetes. The incidence of diabetes in the first year was 0.7, 1.5, 2.9, 9.2, 30.4, and 44.0% in the six HbA_1c groups, respectively. At five years the incidence was 3.6, 8.9, 13.8, 27.5, 51.6, and 67.8%, respectively (p < 0.0001 comparing the HbA_1c ≤5.5% group to the other groups). After adjustment for confounding factors, the hazard ratios compared with the HbA_1c ≤5.5% group were significantly elevated: 2.3 (95%CI 2.0–2.5), 3.4 (95%CI 2.9–3.7), 8.8 (95%CI 8.0–10.1), 26.3 (95%CI 23.3–30.1), and 48.7 (95%CI 40.8–58.1) in the five HbA_1c groups (p < 0.0001).</p><p>Conclusion</p><p>By fractionating baseline HbA_1c levels into narrower HbA_1c range groups, accuracy of estimating the incidence of type 2 diabetes in subsequent years was increased. The risk of developing diabetes increased with increasing HbA_1c levels, especially with the HbA_1c level ≥ 6.2% in the first follow-up year.</p></div

Baseline characteristics of the study population

<p>Values are expressed as medians (range or percentage).</p><p>* Hypertension: Yes = systolic blood pressure ≥140 mmHg, diastolic blood pressure ≥90 mmHg, or treated with anti-hypertension drugs.</p><p>^† Family history of diabetes: Yes = third-degree relatives with diabetes.</p><p>^‡ Exercise habit: Yes = exercised for ≥30 min each time and two or more times per week.</p><p>^§ Smoking habit: No = never smoked or quit smoking > 6 months ago.</p><p>^|| Drinking habit (alcohol consumption habit): Yes (moderate) = consumed alcohol ≥ 3 per week and ≥ 180 mL sake (same as 110 mL distilled spirits (shochu), 60 mL whisky, 200 mL wine, or 500 mL beer) at a time. Yes (heavy) = consumed alcohol ≥ 3 times per week and ≥ 180 mL sake (same as 110 mL distilled spirits (shochu), 60 mL whisky, 200 mL wine, or 500 mL beer) at a time.</p><p>^¶ Odds ratios were adjusted by age, sex, and body mass index.</p><p>95% CI: 95% confidence interval</p><p>.</p

Kaplan—Meier survival curves for incident diabetes during the 5-year study period, differentiated by baseline HbA_1c levels.

<p>Each curve had a significantly higher risk compared with the reference group, the curve for HbA_1c ≤ 5.5% (log-rank P value <0.0001).</p