Biopharma PEG
https://www.biochempeg.com
siRNA Therapeutics: Current Status & Delivery System Nucleic acid therapeutics are a promising way to treat diseases more precisely by introducing a sequence of nucleic acids to up-regulate, down-regulate or correct the target gene. Nucleic acid therapeutics can be divided into two categories according to their compositions: DNA drugs and RNA drugs, among which RNA drugs can be divided into antisense oligonucleotides (ASOs), Small activating RNAs (saRNA), Small interfering RNA (siRNA), microRNAs (miRNAs), mRNA and aptamers.
siRNA is a synthetic double-stranded RNA, consisting of a sense strand and an antisense strand, which form a duplex 19 to 25 bp in length with 3' dinucleotide overhangs. The antisense strand of the siRNA duplex serves as a sequence-specific guide that directs activity of an endoribonuclease function in the RNA induced silencing complex (RISC) to degrade target mRNA.
Specifically speaking, siRNA occurs in four basic steps. First, the long double-stranded RNA (dsRNA) is processed into small interfering RNA (siRNA) duplexes by the nucleic acid endonuclease Dicer protein. Subsequently, the siRNA binds to the Argonaute-2 (AGO2) protein, which is thought to be the core of a multi-protein complex called the RNA-induced silencing complex (RISC). The siRNA is then separated into two single strands: the guide strand and the passenger strand. Finally, the passenger strand is degraded and the guide strand-RISC complex binds to the complementary target mRNAs triggering their degradation.