The study investigates the secretory mechanisms and intercellular transfer of microRNAs (miRNAs) in living cells. The authors demonstrate that miRNAs are released through a ceramide-dependent secretory pathway, and these secreted miRNAs are transferable and functional in recipient cells. Neutral sphingomyelinase 2 (nSMase2), which regulates ceramide biosynthesis, is identified as a key enzyme in this process. Treatment with nSMase2 inhibitors or knockdown of nSMase2 expression reduces miRNA secretion, while overexpression of nSMase2 increases it. The study also shows that the endosomal sorting complex required for transport (ESCRT) system is not necessary for miRNA release. Furthermore, tumor-suppressive miRNAs secreted via this pathway can be transported between cells and exert gene silencing, leading to cell growth inhibition. These findings provide insights into the physiological relevance of secretory miRNAs and their potential roles in intercellular communication and disease.The study investigates the secretory mechanisms and intercellular transfer of microRNAs (miRNAs) in living cells. The authors demonstrate that miRNAs are released through a ceramide-dependent secretory pathway, and these secreted miRNAs are transferable and functional in recipient cells. Neutral sphingomyelinase 2 (nSMase2), which regulates ceramide biosynthesis, is identified as a key enzyme in this process. Treatment with nSMase2 inhibitors or knockdown of nSMase2 expression reduces miRNA secretion, while overexpression of nSMase2 increases it. The study also shows that the endosomal sorting complex required for transport (ESCRT) system is not necessary for miRNA release. Furthermore, tumor-suppressive miRNAs secreted via this pathway can be transported between cells and exert gene silencing, leading to cell growth inhibition. These findings provide insights into the physiological relevance of secretory miRNAs and their potential roles in intercellular communication and disease.