Enhancer RNAs (eRNAs) are short RNA sequences that have been found in many different human diseases. They can be used to identify patients with certain types of cancer, autoimmune disorders, infectious diseases and other conditions.
The eRNA molecule consists of two parts: an “enhancer” region and a “repressor” region. The first part contains genes that code for proteins involved in the production or activity of RNA molecules called ribozymes.
These proteins catalyze reactions that produce various products such as DNA or RNA. The second part of the eRNA molecule contains genes that control how these ribozymes work. For example, one gene controls whether the ribozymes will make a protein that produces energy from glucose, or if they will make a protein that makes your cells resistant to infection.
Some of the most common diseases associated with eRNAs include:
Autoimmune Disorders – Autoimmune disorders are caused by an immune system attack on healthy tissues. Examples of auto-inflammatory diseases include multiple sclerosis, lupus, rheumatoid arthritis and Sjogren’s syndrome.
Some examples of autoimmune disorders that involve eRNAs are type 1 diabetes mellitus (type I DM), Crohn’s disease, celiac sprue and inflammatory bowel disease.
Cancers – Cancers are caused by the uncontrolled growth of cells. The most common types of cancer include leukemia, brain and spinal cord cancer, lung cancer and skin cancer.
More than two hundred different types of eRNAs have been identified in cancers, including multiple myeloma, colorectal cancer, ovarian cancer, B cell lymphomas and glioblastoma.
Viruses – Viruses are tiny infectious particles that can only multiply in living cells. Some viruses, such as the human immunodeficiency virus (HIV), can lead to acquired immunodeficiency syndrome (AIDS), which weakens the immune system and leaves the body open to infection with other viruses and bacteria.
Bacteria – Bacteria are a large group of single-celled microorganisms that reproduce by cell division. There are many different types of bacteria, some of which are beneficial because they help in the digestive process or synthesize vitamins.
Other types of bacteria are harmful because they produce toxins, which cause food poisoning and other illnesses.
Epstein-Barr virus – The Epstein-Barr virus is a member of the herpes virus family. It can cause infectious mononucleosis, which was once called “the kissing disease” because it is usually transmitted by kissing an infected person (often when they have swollen glands in their cheek or neck).
Human T-lymphotropic virus type 1 (HTLV-1) – The HTLV-1 virus belongs to a group of viruses called human retroviruses. If a mother is infected with HIV, there is a one in two chance that her child will also become infected when it is born.
West Nile virus – People infected with the West Nile virus suffer flu-like symptoms such as fever, headache, fatigue, diarrhea and muscle aches. In some cases, the disease can lead to inflammation of the brain or the surrounding tissues.
Pneumonia – Pneumonia is a life-threatening lung infection that causes difficulty in breathing, chest pain, coughing up blood, fevers and difficulty swallowing. People who suffer from weakened immune systems due to other diseases or conditions are at a higher risk of developing pneumonia.
The National Academies of Sciences, Engineering, and Medicine (NASEM) is an independent organization that provides expert advice on scientific issues to a range of federal agencies, Congress and the Administration. In 2015, a report by the NASEM recognized the potential benefits of eRNAs in identifying new drugs to combat cancer and infectious diseases.
In addition to its potential for aiding in the discovery of new drugs, eRNAs are useful for studying normal and diseased cells at a deeper level because they can provide details on both the RNA and proteins produced by genes. This may lead to the identification of biomarkers that can identify inherited diseases and cancer as well as offer insight into how different drugs work.
eRNAs also play a role in the diagnosis and treatment of infectious diseases such as HIV, hepatitis and tuberculosis. There are currently two tests for HIV on the market, one of which looks for the p24 antigen, which is a protein produced by the virus.
The other test looks for HIV-1 RNA, which can be detected from the infected individual’s blood. There is also evidence that eRNAs play a role in autoimmune diseases such as type I diabetes and multiple sclerosis.
- Enhancer RNAs: a class of long noncoding RNAs synthesized at enhancers (TK Kim, M Hemberg, JM Gray – Cold Spring Harbor …, 2015 – cshperspectives.cshlp.org)
- Enhancer RNAs and regulated transcriptional programs (MTY Lam, W Li, MG Rosenfeld, CK Glass – Trends in biochemical sciences, 2014 – Elsevier)
- Enhancer RNAs: a missing regulatory layer in gene transcription (R Mao, Y Wu, Y Ming, Y Xu, S Wang, X Chen… – Science China Life …, 2018 – Springer)