Data from: Identification of a transporter complex responsible for the cytosolic entry of nitrogen-containing-bisphosphonates

Nitrogen-containing-bisphosphonates (N-BPs) are widely prescribed to treat osteoporosis and other bone-related diseases. Although previous studies established that N-BPs function by inhibiting the mevalonate pathway in osteoclasts, the mechanism by which N-BPs enter the cytosol from the extracellular space to reach their molecular target is not understood. Here we implemented a CRISPRi-mediated genome-wide screen and identified SLC37A3 (solute carrier family 37 member A3) as a gene required for the action of N-BPs in mammalian cells. We observed that SLC37A3 forms a complex with ATRAID (all-trans retinoic acid-induced differentiation factor), a previously identified genetic target of N-BPs. SLC37A3 and ATRAID localize to lysosomes and are required for releasing N-BP molecules that have trafficked to lysosomes through fluid-phase endocytosis into the cytosol. Our results elucidate the route by which N-BPs are delivered to their molecular target, addressing a key aspect of the mechanism of action of N-BPs that may have significant clinical relevance.

含氮双膦酸盐（Nitrogen-containing-bisphosphonates，N-BPs）被广泛用于治疗骨质疏松症及其他骨骼相关疾病。既往研究已证实，N-BPs通过抑制破骨细胞内的甲羟戊酸通路发挥功能，但N-BPs如何从细胞外空间进入细胞质以抵达其分子靶点的机制仍未明确。本研究采用CRISPR干扰（CRISPRi）介导的全基因组筛选，在哺乳动物细胞中鉴定出溶质载体家族37成员A3（SLC37A3，solute carrier family 37 member A3）是N-BPs发挥作用所必需的基因。研究发现，SLC37A3与此前已被鉴定为N-BPs遗传靶点的全反式维甲酸诱导分化因子（ATRAID，all-trans retinoic acid-induced differentiation factor）形成复合物。SLC37A3与ATRAID定位于溶酶体，且对于将通过液相内吞作用转运至溶酶体的N-BP分子释放至细胞质中是必需的。本研究结果阐明了N-BPs被递送至其分子靶点的具体通路，解决了N-BPs作用机制中一个具有重要临床意义的关键问题。