RNA Silencing in the Future

In the past few years the use of RNAi-based therapeutic has been highly adopted in treating different diseases. This type of treatment targets and destroys RNA molecules responsible for the production of polypeptides that facilitate disease progression. RNAi treatment is being tested to cure the following diseases that are very common in our society.

Cancer: cancer cells have two characteristics that distinguish them from normal body cells. One of the characteristics of cancer cell is that they have a deregulated cell cycle resulting in Neoplasia (uncontrolled cell division). And the other characteristics of these cells is that they lack proper structures and function differentiation (Anaplasia). Therefore, RNAi is used to prevent the translation of mRNA sequence into a polypeptide which causes ubnobalities in cell division and Anaplasia. However altering cancer cells without affecting normal cells is a very difficult task. Therefore, The RNAi is designed to affect genes that are strictly involved in the production of cancer cells.

HIV: HIV is the first infectious diseases to be targeted by RNAi. This method of utilizing RNAi was used to successfully downgrade cofactors and coreceptors of HIV, preventing the replication of HIV virus in T-cells and hematopoietic-stem-cell-derived macrophages. However, this method affects non-infected cells causing the same effects as the current anti-retroviral drugs. Therefore, shRNA is mixed with antiviral genes to make a more effective combination. Researchers are also trying to come up with a more effective combination of iRNA with a non-iRNA antiviral molecule in the near future. The delivery of iRNA into HIV-infected cell presents another hurdle for scientist to overcome. And since the siRNA does not stay in the cell for long periods, they would also have to deliver siRNAs for years to effectively treat the desease. However systemic delivery is not yet practicable, so T-cells are isolated from the patient; these cells are then transduced, expanded ex vivo, and infused back into the patient. Since the use of RNAi is promising and more effective, this technology is expected be used in human clinical trial for HIV treatment in the next year or two.

Hepatitis Virus: is an infectious disease caused by DNA virus which infects liver cells. This virus uses an enzyme called reverse transcriptase to make DNA strands that will get incorporated into the host genome.  This disease has also caused epidemics in different parts of the world. Eventhough vaccines are available for Hepatitis A and B, there are no treatments for Hepatitis C and for people that are infected.  Therefore, RNAi is used to prevent DNA replication of infected cells and virus gene expression.

Cardiovascular diseases: Cardiovascular diseases are responsible for large number of deaths in the United States and other industrialized countries. Usually this results in Atherosclerosis. This is caused when the damage in the artery walls results in a narrow passage for blood. In most cases this results in stroke or heart attack. RNAi can be used to intervene in the process of atherosclerosis development. This process regulates cell adhesion molecules in vascular cells which in return will result in a higher amount of macrophages in the site of damage. The following video gives a good description about Atherosclerosis.