Biology subjects

Wulf, M. G.

Publications and source records attributed to Wulf, M. G..

3 recordsLinked to original sources

bioRxiv2021

Novel Class of Psychedelic Iboga Alkaloids Disrupts Opioid Addiction States

Substance use and related mental health epidemics are causing increasing suffering and death in diverse communities.1,2 Despite extensive efforts focused on developing pharmacotherapies for treating substance use disorders, there is an urgent need for radically different therapeutic approaches.3,4 Ibogaine provides an important drug prototype in this direction, as a psychoactive iboga alkaloid suggested to have the ability to interrupt opioid use in drug-dependent humans.5 However, ibogaine and its major metabolite noribogaine present considerable safety risk associated with cardiac arrhythmias.6 We introduce a new class of iboga alkaloids - "oxa-iboga" - defined as benzofuran-containing iboga analogs and created via structural editing of the iboga skeleton. The oxa-iboga compounds act as potent kappa opioid receptor agonists in vitro and in vivo, but exhibit atypical behavioral features compared to standard kappa psychedelics. We show that oxa-noribogaine has greater therapeutic efficacy in rat models of opioid use, and no cardiac pro-arrhythmic potential, in contrast to noribogaine. Oxa-noribogaine induces long-lasting suppression of morphine and fentanyl intake after a single dose, persistent reduction of morphine intake and reinforcing efficacy after a short treatment regimen, and suppression of morphine and fentanyl drug seeking in relapse models. Oxa-noribogaine also induces a lasting elevation of neurotrophin proteins in the ventral tegmental area and medial prefrontal cortex, consistent with targeted neuroplasticity induction and alteration of addiction-like states. As such, oxa-iboga compounds represent candidates for a novel type of pharmacotherapy for treatment of opioid use disorder.

pharmacology and toxicology↗

bioRxiv2020

Identification of high confidence human poly(A) RNA isoform scaffolds using nanopore sequencing

Nanopore sequencing devices read individual RNA strands directly. This facilitates identification of exon linkages and nucleotide modifications; however, using conventional methods the 5' and 3' ends of poly(A) RNA cannot be identified unambiguously. This is due in part to the architecture of the nanopore/enzyme-motor complex, and in part to RNA degradation in vivo and in vitro that can obscure transcription start and end sites. In this study, we aimed to identify individual full-length human RNA isoform scaffolds among [~]4 million nanopore poly(A)-selected RNA reads. First, to identify RNA strands bearing 5' m7G caps, we exchanged the biological cap for a modified cap attached to a 45-nucleotide oligomer. This oligomer adaptation method improved 5' end sequencing and ensured correct identification of the 5' m7G capped ends. Second, among these 5'-capped nanopore reads, we screened for ionic current signatures consistent with a 3' polyadenylation site. Combining these two steps, we identified 294,107 individual high-confidence full-length RNA scaffolds, most of which (257,721) aligned to protein-coding genes. Of these, 4,876 scaffolds indicated unannotated isoforms that were often internal to longer, previously identified RNA isoforms. Orthogonal data confirmed the validity of these high-confidence RNA scaffolds.

genomics↗

bioRxiv2019

In vitro characterization of the yeast DcpS, a scavenger mRNA decapping enzyme

Eukaryotic mRNAs are modified at their 5 end early during transcription by the addition of N7-methylguanosine (m7G), which forms the \"cap\" on the first 5 nucleotide. Identification of the 5 nucleotide on mRNA is necessary for determination of the Transcription Start Site (TSS). We explored the effect of various reaction conditions on the activity of the yeast scavenger mRNA decapping enzyme DcpS (yDcpS) and examined decapping of 30 chemically distinct cap structures varying the state of methylation, sugar, phosphate linkage, and base composition on 25mer RNA oligonucleotides. Contrary to the generally accepted belief that DcpS enzymes only decap short oligonucleotides, we found that yDcpS efficiently decaps RNA transcripts as long as 1400 nucleotides. Further, we validated the application of yDcpS for enriching capped RNA using a strategy of specifically tagging the 5 end of capped RNA by first decapping and then recapping it with an affinity-tagged guanosine nucleotide.

molecular biology↗