Where can miRNA be found?

Fully developed miRNAs are found in various parts of the cell's cytoplasm, including RNA granules, mitochondria and endomembranes. They can also be released from cells through exosomes. Research  suggests that these mature miRNAs may also be present in the nucleus, where they might play a role in epigenetic control. While miRNAs primarily function within cells, they can also be detected outside the cell, such as in tissue culture medium or circulating in body fluids like cerebrospinal fluid and blood plasma. Many circulating miRNAs are tissue-specifically expressed and their presence can change in response to pathological or physiological conditions.