mRNA therapeutic
An mRNA therapeutic is a drug that does not contain the medicine itself but the recipe for it. Instead of delivering a finished protein, it delivers a strand of messenger RNA, the cell's instruction sheet, and lets the patient's own cells read it and manufacture the protein on site.
Messenger RNA is the natural intermediate between a gene and a protein. By synthesizing a custom mRNA, scientists can instruct cells to make almost any protein for a short time: a viral fragment that trains the immune system, as in mRNA vaccines, or a missing or therapeutic protein. Because the mRNA is degraded after a few hours to days, the effect is transient and does not alter the patient's own DNA.
The catch is delivery and stability. Bare mRNA is large, negatively charged, and instantly chewed up by enzymes, so it is almost always packaged inside a lipid nanoparticle that protects it and helps it enter cells. Modified RNA letters are also used to keep the immune system from over-reacting to the foreign RNA.
COVID-19 mRNA vaccines deliver the recipe for the viral spike protein, prompting the body's own cells to make it so the immune system learns to recognize the virus.
A drug that supplies instructions, letting the patient's cells make the therapeutic protein.
Unlike gene therapy, mRNA does not enter the nucleus or integrate into DNA; it is read in the cytoplasm and then naturally broken down.