Selective targeting of MAPK family kinases JNK over p38 by rationally designed peptides as potential therapeutics for neurological disorders and epilepsy.

Human mitogen-activated protein kinase (MAPK) family members JNK and p38 are two homologous protein-serine/threonine kinases but play distinct roles in the pathological process of neurological disorders. Selective targeting of JNK over p38 has been established as a potential therapeutic approach to epilepsy and other nervous system diseases. Herein, we describe an integrated in vitro-in silico protocol to rationally design kinase-peptide interaction specificity based on crystal structure data. In the procedure, a simulated annealing (SA) iteration optimization strategy is described to improve peptide selectivity between the two kinases. The optimization accepts moderate compromise in peptide affinity to JNK in order to maximize the affinity difference between peptide interactions with JNK and p38. The structural basis, energetic properties and dynamic behavior of SA-improved peptides bound with the peptide-docking sites of JNK and p38 kinase domains are investigated in detail using atomistic molecular dynamics (MD) simulations and post binding free energy analysis. The theoretical findings and computational designs are then confirmed by fluorescence polarization assays. Using the integrated protocol we successfully obtain three decapeptide ligands, namely RLHPSMTDFL, RAKLPTSVDY and KPSRPWNLEI, that exhibit both potent affinity to JNK (K = 8.0, 5.4 and 12.1 µM, respectively) and high selectivity for JNK over p38 (K/K = 9.2, 17.9 and 6.3 fold, respectively). We also demonstrate that a JNK-over-p38 selective peptide should have a positively charged N-terminus, a polar central region and a negatively charged C-terminus, in which a number of hydrophobic residues distribute randomly along the peptide sequence. In particular, the residue positions 1, 6 and 9 play a crucial role in shaping peptide selectivity; the presence of, respectively, Arg, Thr and Asp at the three positions confers high specificity to kinase-peptide interactions.

Mutation analysis and prenatal diagnosis in a Chinese family with succinic semialdehyde dehydrogenase and a systematic review of the literature of reported ALDH5A1 mutations.

AIMS: Succinic semialdehyde dehydrogenase (SSADH) deficiency is a neurometabolic disease in which the degradation of γ-aminobutyric acid (GABA) is impaired. The purpose of this study was to report two novel ALDH5A1 mutations responsible for SSADH deficiency in a Chinese family and the prenatal diagnosis of an at-risk fetus with DNA sequencing. RESULTS: Genetic analysis of ALDH5A1, in a child with SSADH deficiency, parents, and 10 weeks' gestation at-risk fetus and 100 healthy unrelated volunteers, was performed. The coding sequence and the intron/exon junctions of ALDH5A1 were analyzed by bidirectional DNA sequencing. The proband was identified to have a compound heterozygous mutations with c.496T>C (p.W166R) and c.589G>A (p.V197M). Each of his parents carried a deleterious mutation. DNA sequencing of chorionic villus revealed the fetus was a carrier, but not affected, and this was confirmed after birth by genetic analysis of umbilical cord blood and urine organic acid analysis. A study in 2003 described 35 mutations of ALDH5A1 in 54 unrelated families, and the current study and systematic literature review identified nine additional novel mutations in eight unrelated families bringing the total number of unique mutations of ALDH5A1 resulting in SSADH deficiency to 44, and the 44 mutations occur from exon 1 to exon 10. No mutational hotspots or prevalent mutations were observed, and all mutations appeared vital for the function of SSADH. CONCLUSIONS: Two novel ALDH5A1 mutations likely responsible for SSADH deficiency were identified, and DNA sequencing provided an accurate diagnosis for an at-risk fetus whose sibling had SSADH deficiency.

[Hydroa vacciniforme-like cutaneous T cell lymphoma: a case report and literature review].

OBJECTIVE: To study the clinical features, diagnosis and therapy of hydroa vacciniforme-like cutaneous T cell lymphoma. METHODS: The clinical presentations and the findings of laboratory examinations and skin biopsy of affected tissue in a child with hydroa vacciniforme-like cutaneous T cell lymphoma were retrospectively reviewed. RESULTS: The child manifested as rash, fever and lymph node intumesce. Rash was pantomorphia, including edematous erythema, vesicles, crusts, necrosis and depressed scar, and it was mild in winter and severe in summer, mainly involving in the face and extremities. Epstein-Barre virus (EBV)-IgM was positive. Histopathological findings revealed focal lymphocyte invasion in subcutaneous panniculus adiposus, mainly surrounding the blood vessels. Immunohistochemistry showed CD3 (+), CD43 (+), CD20 (-), pax-5 (-), TIA (+), CD5 (+), CD8 (+), Granmye (+) and CD4 (-). The clinical symptoms were improved after glucocorticoid treatment in this child. CONCLUSIONS: Hydroa vacciniforme-like cutaneous T cell lymphoma has special clinical manifestations. This disorder may be definitely diagnosed by skin biopsy of affected tissue and immunohistochemistry assay. Glucocorticoid treatment is effective. EBV infection may be related to the development of this disorder.