To be effective in vivo, antisense oligonucleotides (AS ON) should be nuclease resistant, form stable ON/RNA duplexes and support ribonuclease H mediated heteroduplex cleavage, all with negligible non-specific effects on cell function. We report herein that AS ONs containing a 2′-deoxy-2′-fluoro-β-d-arabinonucleic acid (2′F-ANA) sugar modification not only meet these criteria, but have the added advantage of maintaining high intracellular concentrations for prolonged periods of time which appears to promote longer term gene silencing. To demonstrate this, we targeted the c-MYB protooncogene's mRNA in human leukemia cells with fully phosphorothioated 2′F-ANA–DNA chimeras (PS-2′FANA–DNA) and compared their gene silencing efficiency with AS ON containing unmodified nucleosides (PS-DNA). When delivered by nucleofection, chemically modified ON of both types effected a >90% knockdown of c-MYB mRNA and protein expression, but the PS-2′F-ANA–DNA were able to accomplish this at 20% of the dose of the PS-DNA, and in contrast to the PS-AS DNA, their silencing effect was still present after 4 days after a single administration. Therefore, our data demonstrate that PS-2′F-ANA–DNA chimeras are efficient gene silencing molecules, and suggest that they could have significant therapeutic potential.
The influence of the immune system deregulation on the risk of schizophrenia is increasingly recognized. The aim of this study was to assess the influence of serum interleukin-6 (IL-6) level together with the polymorphism in its gene (IL6 -174G/C) and high sensitivity C-reactive protein (hsCRP) levels on clinical manifestation and cognition in schizophrenia patients. We recruited 151 patients with schizophrenia and 194 healthy control subjects. Psychopathology was evaluated using Operational Criteria for Psychotic Illness checklist, Positive and Negative Syndrome Scale (PANSS) and Scales for Assessment of Positive and Negative Symptoms. Cognitive performance in schizophrenia patients was assessed using following tests: Rey Auditory Verbal Learning Test, Trail Making Test, Verbal Fluency Tests, Stroop and subscales from Wechsler Adults Intelligence Scale-R-Pl (Similarities, Digit Symbol Coding, Digit Span Forward and Backward). Serum IL-6 and hsCRP levels were significantly higher in schizophrenia patients in comparison with healthy controls. Both hsCRP and IL-6 levels were associated with insidious psychosis onset, duration of illness and chronic schizophrenia course with deterioration. After adjustment for age, education level, number of years of completed education, illness duration, total PANSS score, depression severity and chlorpromazine equivalent, there was still a positive association between IL-6 and hsCRP levels and worse cognitive performance. The IL6 -174G/C polymorphism did not influence IL-6 level, but it was associated with the severity of positive symptoms. Our results suggest that elevated IL-6 levels may play the role in cognitive impairment and serve as potential inflammatory biomarker of deterioration in schizophrenia.
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