DNA Molecular Biology RNA RNA therapeutics

Decoding the Central Dogma of Life

The central dogma of molecular biology is a concept in science. This means that the DNA contains genetic information. RNA then carries this information via the process of transcription. Then the RNA translates the data into peptides’ sequences that carry out numerous functions within the cells.

According to the central dogma of molecular biology, ribonucleic acid & deoxynucleic acids are the molecules that carry the main information in all of the living creatures. However, in terms of stability, DNA is more stable than RNA.  That is why DNA is the main component of chromosomes. These genes contain instructions that make the regulatory, catalytic, and structural proteins.

The Central Dogma of Molecular Biology. Source

 Pepsin is an example of the catalytic proteins, which play an intrinsic role in food digestion. Collagen is an example of a structural protein that is present in the skeletal system of homo sapiens. In short, DNA contains all the information. It also regulates and stores it. This serves as a master copy of such information. When the cell is in a need of a new set of instructions. The activation of DNA occurs. It starts to make multiple copies of the deoxynucleic acid.

Afterward, the ribosomes read the previously made mRNA and begin in the proteins building up process. via a process called translation. Interestingly, the cell can always make continuous copies of RNA to make protein upon requirement.

The diverse biology fields are currently focusing on the molecular revolution which is basically based on both DNA & RNA based techniques in the research and also to help the battle against many serious diseases.

Different Types of RNA

There are several types of RNA which are having regulatory, catalytic, and structural roles. Surprisingly, the ribosomes themselves also contain RNA, the rRNA “ribosomal RNA”. Furthermore, the other types of RNA include tRNA “transfer RNA”, miRNA “microRNA”, and siRNA “small interfering RNA”; as each one of them has its own vital role and function. The tRNA, they’re the building blocks of the proteins and they are 20 – 25 nucleotides long. However, the miRNA is providing an intrinsic regulating role in the production of too much protein; therefore, they’re not totally turning off the protein production; however, they just make it controlled. Another type of the tiny RNA molecules known as siRNA which do have the ability to completely turn off the protein production and hence, silencing the gene expression.

What is RNA Silencing?

In the process of RNA silencing / RNA interference, the protein production is turned off, and this is carried out by the siRNA which is a short RNA molecule whose sequences are complementary to those of mRNA; therefore, when they match; they bong together making a cleavage in the mRNA sequences as a result. Therefore, if the cells keep producing more new mRNAs, the siRNA can proceed to destruct those newly-emerged ones, which in return turn off the protein and silence the gene respectively.

Naturally, the siRNAs are acting as a defense mechanism by attaching the RNA-based viruses. Nowadays, researchers are currently focusing on how to harness siRNAs to treat serious diseases by turning off their protein and silencing their genes. Currently, it has been easy to easily design and synthesize siRNAs that are complementary to the mRNAs which make hope for the treatment of numerous human disorders which can be treated by targeting their genes; and hence, silencing its expression.

RNA Targeting Therapeutics

 It is the use of RNAs molecules like siRNAs & miRNAs as therapeutics, and this is really promising because the RNA is the biological processes center which makes it easy to address human disorders from the RNA level & perspective. 

There are disparate promising technologies to treat serious diseases. These are basically based on the RNA-targeting therapeutics by many methods such as miRNAs, siRNAs, aptamers, antisense oligonucleotides (ASOs). In addition to the most recent one which is synthetic mRNAs. The aim of the previously mentioned ways is to handle & control the gene expression of the disease-related genes. Such nucleotides & molecules do have the ability to bond to the targets which aren’t being easily targeted by small molecules; which allows the researchers to carry out more researches on how to harness them in a view to treat intractable serious diseases.

For ASOs & siRNAs, they are being in the process of clinical development; as the researchers are facing many obstacles & challenges to invent products less immunogenic and more potent, in addition to the difficulty of targeting the right cells in the right tissues as well. However, the success rears its head in 2016 for ASOs.

RNA based Drugs

Nusinersen, approve by the FDA making it the first drug-targeting spinal muscular atrophy. This is a serious killing disease of the nervous system. In 2018, Patisiran an RNAi drug for the treatment of rare liver disease (hereditary transthyretin amyloidosis) was approved by the FDA. Interestingly, those two approved drugs opened the gate for the remaining molecules to be more tested in the clinical studies and gave researchers and patients hope for the treatment of serious diseases that have not been treated before. It additionally created opportunities for further utilization of RNA therapeutics.

In 2016, according to a study, a new method based on siRNA is developed which was the development of antibody-siRNA conjugate targeted to cardiac and skeletal muscles. The conjugation of siRNAs with anti-CD71 Fab’ fragment is Involve in treating muscular organs. Such a conjugation showed that gene silencing in the skeletal muscle has occurred after being given intravenously to normal mice for a month. In particular, 1μg siRNA conjugate showed gene silencing in the gastrocnemius after being intramuscularly injected. In a disease mouse model, the silencing of myostatin has been noticed after injecting mice with myostatin-targeting siRNA conjugate.

Conclusion

The central dogma of molecular biology is not only about DNA, RNA, and proteins. It comprises all the information, utilization, and importance of the above-stated molecules. And, how it shapes the life of every organism present on this earth. There are disparate promising technologies to treat serious diseases which are basically based on the RNA-targeting therapeutics by many methods such as miRNAs, siRNAs, aptamers, antisense oligonucleotides (ASOs) to handle & control the gene expression of the disease-related genes. Some of which are being in clinical trials.  While remaining have shown significant results.

 

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