Phosphorodiamidate morpholino oligonucleotides (PMOs) constitute 3 out of the 11 FDA-approved oligonucleotide-based drugs in the last 6 years. PMOs can effectively silence disease-causing genes and modify splicing. However, PMO synthesis has remained challenging for a variety of reasons: inefficient deprotection and coupling methods and instability of monomers. Here, we report the development of a suitable combination of resin supports, deblocking and coupling reagents for synthesizing PMOs using either trityl or Fmoc-protected chlorophosphoramidate monomers. The synthesized PMOs using both the methods on a solid support have been validated for gene silencing in a zebrafish model. The protocol was successfully transferred into an automated DNA synthesizer to make several sequences of PMOs, demonstrating for the first time the adaptation of regular PMOs in a commercial DNA synthesizer. Moreover, PMOs with longer than 20-mer sequences, including FDA-approved Eteplirsen (30-mer), were achieved in >20% overall yield that is superior to previous reports. Hybridization study shows that PMOs exhibit a higher binding affinity toward complementary DNA relative to the DNA/DNA duplex (>6 °C). Additionally, the introduction of Fmoc chemistry into PMOs opens up the possibility for PMO synthesis in commercial peptide synthesizers for future development.

C5-substituted uridine and cytidine morpholino chlorophosphoramidate monomers were synthesized and incorporated into a 12-mer Phosphorodiamidate Morpholino Oligonucleotide (PMO) using semi-automated solid phase synthesis. 5-Substituted pyrimidines incorporated PMO significantly increase the...

Introduction and objectiveCholesterol homeostasis is a culmination of cellular synthesis, efflux, and catabolism to important physiological entities where short chain fatty acid, butyrate embodied as a key player. This discourse probes the mechanistic molecular details of butyrate action in maintaining host-cholesterol balance.MethodsHepatic mir-122 being the most indispensable regulator of cholesterol metabolic enzymes, we studied upstream players of mir-122 biogenesis in the presence and absence of butyrate in Huh7 cells and mice model. We synthesized unique self-transfecting GMO (guanidinium-morpholino-oligo) linked PMO (Phosphorodiamidate-Morpholino Oligo)-based antisense cell-penetrating reagent to selectively knock down the key player in butyrate mediated cholesterol regulation.ResultsWe showed that butyrate treatment caused upregulation of RNA-binding protein, AUF1 resulting in RNase-III nuclease, Dicer1 instability, and significant diminution of mir-122. We proved the importance of AUF1 and sequential downstream players in AUF1-knock-down mice. Injection of GMO-PMO of AUF1 in mouse caused near absence of AUF1 coupled with increased Dicer1 and mir-122, and reduced serum cholesterol regardless of butyrate treatment indicating that butyrate acts through AUF1.ConclusionThe roster of intracellular players was as follows: AUF1-Dicer1-mir-122 for triggering butyrate driven hypocholesterolemia. To our knowledge this is the first report linking AUF-1 with cholesterol biogenesis.

This discourse probes the mechanistic molecular details of butyrate action in maintaining host- cholesterol balance. Hepatic miR122 being the most indispensable regulator of cholesterol metabolic enzymes, we studied upstream players of miR122 biogenesis in the presence and absence of butyrate in Huh7 cells and mice model. We showed that butyrate treatment caused upregulation of RNA-binding protein, AUF-1 resulting in RNase-III nuclease, Dicer-1 instability, and significant diminution of miR122. We proved its importance of AUF-1 and sequential downstream players in AUF-1-knock-down mice. We synthesized unique self-transfecting GMO (guanidinium-morpholino- oligonucleotides) linked PMO (Phosphorodiamidate-Morpholino Oligonucleotides)-based antisense reagent and injection of which in mouse caused near absence of AUF-1 coupled with increased Dicer- 1 and miR122, and reduced serum cholesterol regardless of butyrate treatment indicating that butyrate acts though AUF-1. The roster of intracellular players was as follows: AUF-1-Dicer-1-miR122 for triggering butyrate driven hypocholesterlaemia. To our knowledge this is the first report linking AUF-1 with cholesterol biogenesis.

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