A new mechanism for mtDNA pathogenesis: impairment of post-transcriptional maturation leads to severe depletion of mitochondrial tRNA(Ser(UCN)) caused by T7512C and G7497A point mutations

We have studied the consequences of two homoplasmic, pathogenic point mutations (T7512C and G7497A) in the tRNA(Ser(UCN)) gene of mitochondrial (mt) DNA using osteosarcoma cybrids. We identified a severe reduction of tRNA(Ser(UCN)) to levels below 10% of controls for both mutations, resulting in a 40% reduction in mitochondrial protein synthesis rate and in a respiratory chain deficiency resembling that in the patients muscle. Aminoacylation was apparently unaffected. On non-denaturating northern blots we detected an altered electrophoretic mobility for G7497A containing tRNA molecules suggesting a structural impact of this mutation, which was confirmed by structural probing. By comparing in vitro transcribed molecules with native RNA in such gels, we also identified tRNA(Ser(UCN)) being present in two isoforms in vivo, probably corresponding to the nascent, unmodified transcripts co-migrating with the in vitro transcripts and a second, faster moving isoform corresponding to the mature tRNA. In cybrids containing either mutations the unmodified isoforms were severely reduced. We hypothesize that both mutations lead to an impairment of post-transcriptional modification processes, ultimately leading to a preponderance of degradation by nucleases over maturation by modifying enzymes, resulting in severely reduced tRNA(Ser(UCN)) steady state levels. We infer that an increased degradation rate, caused by disturbance of tRNA maturation and, in the case of the G7497A mutant, alteration of tRNA structure, is a new pathogenic mechanism of mt tRNA point mutations

Neurologic phenotypes associated with COL4A1/2 mutations

Objective: To characterize the neurologic phenotypes associated with COL4A1/2 mutations and to seek genotype–phenotype correlation. Methods: We analyzed clinical, EEG, and neuroimaging data of 44 new and 55 previously reported patients with COL4A1/COL4A2 mutations. Results: Childhood-onset focal seizures, frequently complicated by status epilepticus and resistance to antiepileptic drugs, was the most common phenotype. EEG typically showed focal epileptiform discharges in the context of other abnormalities, including generalized sharp waves or slowing. In 46.4% of new patients with focal seizures, porencephalic cysts on brain MRI colocalized with the area of the focal epileptiform discharges. In patients with porencephalic cysts, brain MRI frequently also showed extensive white matter abnormalities, consistent with the finding of diffuse cerebral disturbance on EEG. Notably, we also identified a subgroup of patients with epilepsy as their main clinical feature, in which brain MRI showed nonspecific findings, in particular periventricular leukoencephalopathy and ventricular asymmetry. Analysis of 15 pedigrees suggested a worsening of the severity of clinical phenotype in succeeding generations, particularly when maternally inherited. Mutations associated with epilepsy were spread across COL4A1 and a clear genotype–phenotype correlation did not emerge. Conclusion: COL4A1/COL4A2 mutations typically cause a severe neurologic condition and a broader spectrum of milder phenotypes, in which epilepsy is the predominant feature. Early identification of patients carrying COL4A1/COL4A2 mutations may have important clinical consequences, while for research efforts, omission from large-scale epilepsy sequencing studies of individuals with abnormalities on brain MRI may generate misleading estimates of the genetic contribution to the epilepsies overall

MOESM1 of DNA analysis of molluscs from a museum wet collection: a comparison of different extraction methods

Additional file 1. In the additional file a detailed list of all samples used in this study can be found, including sample age and the inventory numbers. Furthermore, the DNA concentration [ng/Âľl] for both extraction methods (Promega-THK and the Gen-ial-ATK) and the formaldehyde content [mg/l] are given. The PCR success of all samples is indicated as well

Transcription Factors STAT3 and MYC Are Key Players of Human Platelet Lysate-Induced Cell Proliferation

Human platelet lysate (HPL) is an efficient alternative for animal serum supplements, significantly enhancing stromal cell proliferation. However, the molecular mechanism behind this growth-promoting effect remains elusive. The aim of this study was to investigate the effect of HPL on cell cycle gene expression in different human stromal cells and to identify the main key players that mediate HPL’s growth-enhancing effect. RT-qPCR and an antibody array revealed significant upregulation of cell cycle genes in stromal cells cultured in HPL. As HPL is rich in growth factors that are ligands of tyrosine kinase receptor (TKR) pathways, we used TKR inhibitors and could significantly reduce cell proliferation. Genome profiling, RT-qPCR and Western blotting revealed an enhanced expression of the transcription factors signal transducer and activator of transcription 3 (STAT3) and MYC, both known TKR downstream effectors and stimulators of cell proliferation, in response to HPL. In addition, specifically blocking STAT3 resulted in reduced cell proliferation and expression of cell cycle genes. Our data indicate that HPL-enhanced cell proliferation can, at least in part, be explained by the TKR-enhanced expression of STAT3 and MYC, which in turn induce the expression of genes being involved in the promotion and control of the cell cycle

Clinical and Experimental Medicine / Myostatin and other musculoskeletal markers in lung transplant recipients

Recipients of lung transplantation (LuTx) may experience impaired muscle function and bone metabolism even after rehabilitation. We investigated the potential use of musculoskeletal markers in identifying the impairment of muscle function and bone function in these patients. Biochemical parameters, bodily functions, and lung function of 37 LuTx recipients were evaluated at the time of their discharge from the hospital stay and about 6 months later. The biomarkers were also assessed in 30 healthy age and gender distribution-matched controls. Compared to controls, the negative muscle regulator myostatin was elevated in LuTx recipients at baseline and follow-up, whereas its opponent follistatin only showed a group-specific difference at follow-up. LuTx recipients had reduced serum levels of sclerostin and increased levels of dickkopf 1 and periostin. Lung function and physical function were improved during follow-up. The change in lung function was correlated with the change in chair-rising time and the 6-min walking test. At follow-up, all musculoskeletal markers of LuTx recipients differed from those of controls, thus reflecting their still reduced lung function and bodily functions. Among the tested biomarkers, myostatin, sclerostin, dickkopf 1, and periostin were useful to detect impaired musculoskeletal function in LuTx recipients. Myostatin may serve as a target of treatment in the future.(VLID)365678

Supplementary Tables -Supplemental material for Impact of nutritional status on pulmonary function after lung transplantation for cystic fibrosis

<p>Supplemental material, Supplementary Tables for Impact of nutritional status on pulmonary function after lung transplantation for cystic fibrosis by Katharina Staufer, Emina Halilbasic, Peter Hillebrand, Solveig Harm, Stefan Schwarz, Peter Jaksch, Danijel Kivaranovic, Walter Klepetko, Michael Trauner and Lili Kazemi-Shirazi in United European Gastroenterology Journal</p