PSMD14 is a novel prognostic marker and therapeutic target in osteosarcoma.

BACKGROUND: Osteosarcoma is a bone tumor that is characterized by high malignancy and a high mortality rate, and that originates from primitive osteoblastic mesenchymal cells and is most common in rapidly growing long bones. PSMD14, also known as RPN11 or POH1, is a member of the JAMM isopeptidase family, which is able to remove the substrate protein ubiquitination label, thereby regulating the stability and function of the substrate protein. In this study, we explored the expression and potential biological significance of the PSMD14 deubiquitinating enzyme in osteosarcoma. METHODS: Immunohistochemical methods were used to detect the expression of PSMD14 in biopsies of 91 osteosarcoma patients, and the specimens were classified into high and low PSMD14 expression groups. The correlation between PSMD14 expression and clinical indicators and prognosis was compared.SiRNA was used to downregulate PSMD14 in two osteosarcoma cell lines (HOS and SJSA-1), and the effects of downregulation of PSMD14 on the viability, proliferation, and invasion ability of osteosarcoma cells were analyzed. RESULTS: We identified significant differences in recurrence, metastasis, and survival time of the osteosarcoma patients on the basis of PSMD14 expression. High expression of PSMD14 in osteosarcoma patients was associated with a low survival rate and high risk of metastasis and recurrence. Down-regulation of PSMD14 inhibited the viability, proliferation, and invasiveness of osteosarcoma cell lines. CONCLUSIONS: PSMD14 may be a new prognostic marker and therapeutic target for osteosarcoma.

Maternally transmitted diabetes mellitus may be associated with mitochondrial ND5 T12338C and tRNAAla T5587C variants.

INTRODUCTION: Mutations/variants in mitochondrial genomes are found to be associated with type 2 diabetes mellitus (T2DM), but the pathophysiology of this disease remains largely unknown. AIM: The aim of this study is to investigate the relationship between mitochondrial DNA (mtDNA) variants and T2DM. METHODOLOGY: A maternally inherited T2DM pedigree is underwent clinical, genetic, and molecular assessment. Moreover, the complete mitochondrial genomes of the matrilineal relatives of this family are PCR amplified and sequenced. We also utilize the phylogenetic conservation analysis, haplogroup classification, and the pathogenicity scoring system to determine the T2DM-associated potential pathogenic mtDNA variants. RESULT: Four of seven matrilineal relatives of this pedigree suffered from T2DM with variable ages of onset. Screening for the entire mtDNA genes of matrilineal members reveals co-existence of ND5 T12338C and tRNAAla T5587C variants, as well as 21 genetic polymorphisms which belong to East Asian haplogroup F2. Interestingly, the T12338C variant causes the alternation of first amino acid Met to Thr, shortened two amino acids of ND5 protein. Furthermore, T5587C variant is located at position 73 in the 3'end of mt-tRNAAla and may have structural and functional consequences. CONCLUSIONS: The co-occurrence of ND5 T12338C and tRNAAla T5587C variants may impair the mitochondrial function, which are associated with the development of T2DM in this family.

Mitochondrial ND1 T4216C and ND2 C5178A mutations are associated with maternally transmitted diabetes mellitus.

Mutations in mitochondrial DNA (mtDNA) are important causes for type 2 diabetes mellitus (T2DM). To investigate the association between mtDNA mutations/variants and diabetes, we reported here clinical, genetic and biochemical characterization of a Chinese pedigree with maternally transmitted T2DM. Using PCR and direct sequencing analysis of mitochondrial genomes from the matrilineal relatives, we identified two potential pathogenic mutations, m.T4216C (p.Y304H) and m.C5178A (p.L237M) in the ND1 and ND2 genes, respectively, together with a set of genetic polymorphisms belonging to the human mitochondrial haplogroup D4b. Moreover, by isolating and analyzing polymononuclear leukocytes generated from the T2DM patients and controls, we identified lower levels of mitochondrial membrane potential and ATP production in T2DM patients than in the controls, in contrast, a significantly higher level of reactive oxygen species was observed in the T2DM patients carrying both of the m.T4216C and m.C5178A mutations (p < 0.05 for all). In addition, the plasma levels of malondialdehyde and 8-hydroxydeoxyguanosine in the T2DM patients markedly increased, while the level of superoxide dismutase decreased (p < 0.05 for all). Taken together, our data indicated that the ND1 T4216C and ND2 C5178A mutations may lead to oxidative stress and impair the mitochondrial function, and this, in turn, might have been involved in the pathogenesis and progression of T2DM in this pedigree. Thus, our study provides novel insight into the pathophysiology of T2DM that is manifested by mitochondrial dysfunction.

Mitochondria-targeted antioxidant therapy for an animal model of PCOS-IR.

Polycystic ovary syndrome (PCOS) is a common endocrine disorder with unknown etiology and unsatisfactory clinical treatment. Considering the ethical limitations of studies involving humans, animal models that reflect features of PCOS and insulin resistance (IR) are crucial resources in investigating this syndrome. Our previous study showed that mitochondrial dysfunction resulted from pathogenic mutations of mitochondrial DNA (mtDNA), and that oxidative stress had an active role in the phenotypic manifestation of PCOS­IR. Therefore, it was hypothesized that limiting oxidative stress and mitochondrial damage may be useful and effective for the clinical treatment of PCOS­IR. For this purpose, the present study examined the therapeutic effects of the mitochondria­targeted antioxidant MitoQ10 for PCOS­IR. Furthermore, the histopathology was used to analysis the ovarian morphological changes. The endocrine and reproductive related parameters were analyzed by ELISA approach. A PCOS­IR model was successfully established by subcutaneous injection of rats with testosterone propionate and feeding a high­fat diet. The 30 female Sprague­Dawley rats were then divided into three groups, comprising a control (n=10), animal model (PCOS­IR, n=10) and MitoQ10 treatment (n=10) group. It was found that MitoQ10 significantly improved the IR condition and reversed the endocrine and reproductive conditions of PCOS. In addition, the impaired mitochondrial functions were improved following MitoQ10 administration. Notably, western blot results suggested that this antioxidant reduced the expression levels of apoptosis­related proteins cytochrome c and B­cell lymphoma­2 (Bcl­2)­associated X protein, whereas the anti­apoptotic protein Bcl­extra large was increased following MitoQ10 treatment. Taken together, the data indicated that the MitoQ10 may have a beneficial favorable therapeutic effect on animals with PCOS­IR, most likely via the protection of mitochondrial functions and regulation of programmed cell death­related proteins.

Mitochondrial tRNAThr 15891C>G mutation was not associated with Leber's hereditary optic neuropathy in Han Chinese patients.

Mutations in mitochondrial DNA (mtDNA) were the most important causes of Leber's hereditary optic neuropathy (LHON). To date, approximately 25 LHON-associated mtDNA mutations have been identified in various ethnic populations. Three primary mutations, the 3460G > A, 11778G > A and 14484T > C, in genes encoding the subunits of respiratory chain complex I, were the most common LHON-associated mtDNA mutations. Moreover, secondary mutations in mt-tRNA genes have been reported increasingly to be associated with LHON, simply due to the high mutation rates of mt-tRNAs. There is a lack of functional analysis and a poor genetic evaluation of a certain mt-tRNA mutation, which failed to meet the classic pathogenicity scoring system. As a result, how to classify a pathogenic mutation in mt-tRNA gene became important for both geneticist and clinician to diagnosis the LHON or the suspicious of LHON. In this study, we reassessed the role of a point mutation in mt-tRNA(Thr) gene which had been reported to be a mutation associated with LHON, the pathogenicity of this mutation has been discussed in this context.