Antibiotics as tool to investigate cell functional state

In recent years, the use of antibiotics beyond their canonical antibacterial role has come to represent a field with a wide range of applications. Antibiotics have been studied as a tool to overcome drug resistance in cancer cells, modulate enzymatic and inflammatory responses, mark cell function in pathologies related to changes in protein or lipid profile, and regulate cell redox homeostasis in some pathophysiological conditions. For example, myriocin is employed in biochemical research to deplete sphingolipids by inhibiting the de novo synthesis of ceramide, whereas filipin, as a naturally fluorescent polyene antibiotic that selectively binds to cholesterol, is commonly used as an accurate histochemical marker for the diagnosis of disorders that lead to the accumulation of cholesterol in lysosomal organelles. Furthermore, some naturally occurring antibiotics have been studied as a subgroup of small signaling molecules that influence the gene expression of many cellular functions. This Special Issue focuses on the structural and functional aspects of the alternative use of antibiotics and on the continuous progress performed in antibiotic research in the fields of genetics, molecular biology and synthesis by biocatalysis, as well as biotechnological and biomedical applications.