RNA - Genetherapys

RNA drugs: making sense of it all

RNA (Ribonucleic acid) is a molecule, better yet; RNA is a class of molecules synthesized from DNA during a process called transcription. As described in last week’s post, DNA holds the genetic instructions transcribed onto RNA to carry out its function, therefor RNA could not exist without DNA. It makes sense if we consider DNA as the template for RNA.
RNA is quite similar to DNA but it does hold some differences. Structurally, RNA is single-stranded whereas DNA is double-stranded. RNA is less stable than DNA making it more susceptible to degradation. Defined by its four nitrogenous bases, the T (thymine) found in DNA is replaced with U (uracil), therefore RNA consists of A (adenine), C (cytosine), G (guanine), and U (uracil). For RNA and DNA guanine always binds with cytosine (G-C) but in RNA, adenine binds with uracil (A-U).

Creating innovative drugs by taking RNA and forming small double-strands in specific regions

Our cells constantly produce RNA, which is essential for the synthesis of proteins and the correct functioning of organisms.

Proteins play a fundamental role in the body. Amino acids in proteins synthesize various neurotransmitters that influence our emotions and desires, such as cravings for chocolate. Furthermore, proteins form small channels on cell membranes that communicate between cells and determine compatibility. Proteins can also act as antigens that define the identity of cells, like identifying the players of a sports team by their uniform.

The function of RNA is not only to make proteins. Knowing that only 2% of the human genome contains protein-coding genes, the scientific community long believed the other 98% was junk. Today, the same community defines these residual non-protein-producing genes as noncoding DNA.

Noncoding DNA has a function that is of high scientific interest and attention. Scientists want to know why cells produce so much RNA while maintaining efficiency and avoiding wasted energy.  Scientists hypothesized and then proved that RNA also performs other crucial functions. One of their most important function is the ability of RNA to regulate cellular activities.

Found in the nucleus, DNA code converts to RNA by a process of transcription. However, proteins are made in the cytoplasm. Therefore, to carry out their functions RNAs, such as mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA), must be exported into the cytoplasm.

What are we referring to when we talk about RNA drugs?

Today, scientists seek to exploit the unique properties of RNA/RNA pairs, including RNA interference (RNAi) and antisense oligonucleotides (ASOs) to influence protein translation that alters the levels and quality of protein expression. Some RNA drugs enter the nucleus, modify the expression of the mRNAs destined to become proteins, and correct their expression. Such is the case for treating spinal muscular atrophy (SMA). Furthermore, mRNA-based drugs can immediate protein production as they bypass traditional RNA synthesis and transport steps, as seen with COVID-19 mRNA vaccines. Finally, some small synthetic RNAs called aptamers can bind to proteins and block their action, offering a further innovative therapeutic tool.

RNA drugs offer an innovative way of acting on genes, not by altering their structure, but by modulating their expression. This action is temporary, so the therapies are not a “one-shot deal”, but their effectiveness is surprising. Compared to traditional drugs, they boast a targeted action on specific molecular targets and flexible administration, which can vary from once a month to once every six months. Looking ahead, RNA-based therapies could dominate the medical field, leveraging years of genetic studies and selectively targeting the disease causes.

 

 

Written by

PharmaTech Academy student Laura De Cantis

and the Foundation’s editorial staff

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