Advance in animal model and therapeutic drugs for progressive muscular dystrophy / 中国药理学通报

Progressive muscular dystrophy is an X-linked recessive hereditary degenerative disease caused by dystrophin gene defects, and there is currently no effective treatment.With the further study of progressive muscular dystrophy, a series of animal models have been developed to evaluate the efficacy of drugs, such as muscular dystrophy protein deficiency mice, double gene knockout Duchenne muscular dystrophy phenotype mice, muscular dystrophy dogs and zebrafish muscular dystrophy models.A variety of therapeutic strategies and dmgs are under development, such as inhibition of nonsense mutations, exon hopping therapy, gene therapy, calcium toxicity relieving drugs and antioxidants.This article reviews the pathogenesis, establishment and evaluation of animal models and the therapeutic drngs of progressive muscular dystrophy.

Mitochondria and tumors: A new perspective.

BACKGROUND: Mitochondrial DNA (Mt DNA) defects have been identified in a variety of Tumors, but the exact role of these defects in the pathogenicity and tumor progression is poorly understood. This study aims at identifying the status of mitochondrial OXPHOS genes in neoplastic transformation and attempts to establish a cause and effect relationship between mitochondrial OXPHOS defects and tumor progression. MATERIALS AND METHODS: Mutational, expression and functional analysis of l2 of the 13 mitochondrial OXPHOS genes has been carried out using PCR, Real-Time PCR and protein modeling in 180 sporadic samples of a heterogeneous group of benign and malignant tumors like that of benign, malignant, matched blood and adjacent normal tissue of breast and benign hemangioma. RESULTS: Mutations were identified in the ND4L, ND6 and COX-II regions of the mitochondrial OXPHOS genes. All the mutations were limited only to the malignant breast tissues. On relative quantification, a compromised expression of OXPHOS genes was identified in all the malignant tissues irrespective of their mutational states. Protein modeling revealed loss of function mutations of ND6 and COX-II proteins. CONCLUSION: This is the first study worldwide wherein a comparative study using different benign and malignant tumors has been carried out to assess the role of Mt DNA defects. Our data reveals mitochondrial dysfunction only in malignant cells and not in their benign counterparts, indicating that the dysfunction may arise after the pro-proliferative pathway has set in. We hypothesize that compromised OXPHOS may be a responsive mechanism of the cell to counter cancers, rather than a mechanism of initiating tumorigenesis.

Preimplantation Genetic Diagnosis for Ornithine Transcarbamylase Deficiency by Simultaneous Analysis of Duplex-nested PCR and Fluorescence In Situ Hybridization: A Case Report

Ornithine transcarbamylase (OTC) deficiency is an X-linked co-dominant disorder. A couple, with a previous history of a neonatal death and a therapeutical termination due to OTC deficiency, was referred to our center for preimplantation genetic diagnosis (PGD). The female partner has a nonsense mutation in the exon 9 of the OTC gene (R320X). We carried out nested polymerase chain reaction (PCR) for R320X mutation and fluorescence in situ hybridization (FISH) for aneuploidy screening. Among a total of 11 embryos, two blastomeres per embryo from 9 embryos were biopsied and analyzed by duplex-nested PCR and FISH, and one blastomere per embryo from 2 embryos by only duplex-nested PCR. As a result of PCR and restriction fragment length polymorphism analysis, four embryos were diagnosed as unaffected embryos having the normal OTC gene. Among these embryos, only one embryo was confirmed as euploidy for chromosome X, Y and 18 by FISH analysis. A single normal embryo was transferred to the mother, yielding an unaffected pregnancy and birth of a healthy boy. Based on our results, PCR for mutation loci and FISH for aneuploidy screening with two blastomeres from an embryo could provide higher accuracy for the selection of genetically and chromosomally normal embryos in the PGD for single gene defects.

Studies of GH gene defects in familial Isolated Growth Hormone Deficiency (IGHD).

One family with isolated GH deficiency (IGHD) was Studied. To determine GHI gene deletions, PCR and Southern blot analyses were used. None of the possible deletions were found in the subjects but the GH1 gene mutation was found. The family consisted of parents (both 140 cm) and their three children with isolated GHD. The daughter and two sons were first seen between 2.9 and 5.3 years of age when their HtSDSs were -2.2 to -3.6, and peak GHs were 0.9 to 4.0 mg/ml. The GH1 gene change was found in G-->A substitution at +28 in the intervening sequence or intron 3 (IVS3+28 G-->A). This change is a dominant-negative mutation which has never occurred in any reports in any reports in Thailand and we were the first group to report here. The segregation which and expression studies of the IVS3+28 G-->A variant are underway to confirm whether it is a new dominant-negative mutation that causes GHD by perturbing mRNA splicing.