Novel mutation of the PRNP gene of a clinical CJD case

BACKGROUND: Transmissible spongiform encephalopathies (TSEs), a group of neurodegenerative diseases, are thought to be caused by an abnormal isoform of a naturally occurring protein known as cellular prion protein, PrP(C). The abnormal form of prion protein, PrP(Sc )accumulates in the brain of affected individuals. Both isoforms are encoded by the same prion protein gene (PRNP), and the structural changes occur post-translationally. Certain mutations in the PRNP gene result in genetic TSEs or increased susceptibility to TSEs. CASE PRESENTATION: A 70 year old woman was admitted to the hospital with severe confusion and inability to walk. Relatives recognized memory loss, gait and behavioral disturbances over a six month period prior to hospitalization. Neurological examination revealed Creutzfeldt-Jakob disease (CJD) related symptoms such as incontinence, Babinski sign and myoclonus. EEG showed periodic sharp waves typical of sporadic CJD and cerebrospinal fluid analysis (CSF) was positive for the presence of the 14-3-3-protein. As the disease progressed the patient developed akinetic mutism and died in the tenth month after onset of the disease symptoms. Unfortunately, no autopsy material was available. PRNP sequencing showed the occurrence of a point mutation on one allele at codon 193, which is altered from ACC, coding for a threonine, to ATC, encoding an isoleucine (T193I). CONCLUSION: Here we report a novel mutation of the PRNP gene found in an elderly female patient resulting in heterozygosity for isoleucine and threonine at codon 193, in which normally homozygosity for threonine is expected (T193). The patient presented typical clinical symptoms of CJD. EEG findings and the presence of the 14-3-3 protein in the CSF, contributed to CJD diagnosis, allowing the classification of this case as a probable CJD according to the World Health Organization (WHO) accepted criteria

L-Dopa decarboxylase interaction with the major signaling regulator ΡΙ3Κ in tissues and cells of neural and peripheral origin

L-Dopa decarboxylase (DDC) catalyzes the decarboxylation of L-Dopa to dopamine and 5-hydroxytryptophan (5-HTP) to serotonin. Although DDC has been purified from a variety of peripheral organs, including the liver, kidney and pancreas, the physiological significance of the peripherally expressed enzyme is not yet fully understood. DDC has been considered as a potential novel biomarker for various types of cancer, however, the role of DDC in the development of hepatocellular carcinoma (HCC) remains to be evaluated. Phosphatidylinositol 3-kinase (PI3K), on the other hand, has been shown to play a key role in the tumorigenesis, proliferation, metastasis, apoptosis, and angiogenesis of HCC by regulating gene expression. We initially identified the interaction of DDC with PI3K by means of the phage display methodology. This association was further confirmed in human hepatocellular carcinoma cell lines, human embryonic kidney cells, human neuroblastoma cells, as well as mouse brain, by the use of specific antibodies raised against DDC and PI3K. Functional aspects of the above interaction were studied upon treatment with the DDC inhibitor carbidopa and the PI3K inhibitor LY294002. Interestingly, our data demonstrate the expression of the neuronal type DDC mRNA in HCC cells. The present investigation provides new evidence on the possible link of DDC with the PI3K pathway, underlining the biological significance of this complex enzyme. © 2019 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM

Proteinase K-Resistant Material in ARR/VRQ Sheep Brain Affected with Classical Scrapie Is Composed Mainly of VRQ Prion Protein▿†

Classical scrapie is a prion disease in sheep and goats. In sheep, susceptibility to disease is genetically influenced by single amino acid substitutions. Genetic breeding programs aimed at enrichment of arginine-171 (171R) prion protein (PrP), the so-called ARR allele, in the sheep population have been demonstrated to be effective in reducing the occurrence of classical scrapie in the field. Understanding the molecular basis for this reduced prevalence would serve the assessment of ARR adaptation. The prion formation mechanism and conversion of PrP from the normal form (PrPC) to the scrapie-associated form (PrPSc) could play a key role in this process. Therefore, we investigated whether the ARR allele substantially contributes to scrapie prion formation in naturally infected heterozygous 171Q/R animals. Two methods were applied to brain tissue of 171Q/R heterozygous sheep with natural scrapie to determine the relative amount of the 171R PrP fraction in PrPres, the proteinase K-resistant PrPSc core. An antibody test differentiating between 171Q and 171R PrP fragments showed that PrPres was mostly composed of the 171Q allelotype. Furthermore, using a novel tool for prion research, endoproteinase Lys-C-digested PrPres yielded substantial amounts of a nonglycosylated and a monoglycosylated PrP fragment comprising codons 114 to 188. Following two-dimensional gel electrophoresis, only marginal amounts (<9%) of 171R PrPres were detected. Enhanced 171Rres proteolytic susceptibility could be excluded. Thus, these data support a nearly zero contribution of 171R PrP in PrPres of 171R/Q field scrapie-infected animals. This is suggestive of a poor adaptation of classical scrapie to this resistance allele under these natural conditions

Disinfection by Chemical Oxidation Methods

Poor quality in drinking water is primary cause of pathogen transmission and responsible of varied infectious diseases. Methods of water treatment for human consumption must pay special attention on microbiological safe disinfection. Indeed, from the past few years laws all around the world have included new, more stringent water quality parameters. Chlorination and other mainly used conventional disinfection processes usually do not achieve full inactivation of all microorganisms present in real water supplies, whereas the presence of even low concentrations of organic matter can lead to form harmful disinfection by-products. Protozoan parasites Giardia sp. and Cryptosporidium sp. are some of the microorganisms that cannot be completely inactivated via chlorination under the same contact times typical of bacteria or virus elimination. It has increased toxicological and microbiological risks as well as operational costs. Disinfection by the advanced oxidation process more intensively studied in the past few years has been reviewed including Fenton and photo-Fenton processes and photocatalytic and electro-catalytic variants; this vibrant topic still remains partially uncovered in the available scientific background, which has motivated many recent researches and publications. This chapter is then devoted to briefly review the most recent reports studying the disinfecting potential displayed by mentioned AOPs with respect to widely and currently used conventional techniques. Revision of the inactivation of water-borne pathogens including E. coli, total coliforms, parasites as Giardia and Cryptosporidium, and virus such as coliphages has focused on advantages and disadvantages in application of every particular AOP, their disinfecting mechanisms, and the main parameters affecting the disinfection response