Programmable Tetrahedral DNA-RNA Nanocages Woven with Stimuli-Responsive siRNA for Enhancing Therapeutic Efficacy of Multidrug-Resistant Tumors.

Multidrug resistance (MDR) is a major obstacle limiting the effectiveness of chemotherapy against cancer. The combination strategy of chemotherapeutic agents and siRNA targeting drug efflux has emerged as an effective cancer treatment to overcome MDR. Herein, stimuli-responsive programmable tetrahedral DNA-RNA nanocages (TDRN) have been rationally designed and developed for dynamic co-delivery of the chemotherapeutic drug doxorubicin and P-glycoprotein (P-gp) siRNA. Specifically, the sense and antisense strand sequences of the P-gp siRNA, which are programmable bricks with terminal disulfide bond conjugation, are precisely embedded in one edge of the DNA tetrahedron. TDRN provides a stimuli-responsive release element for dynamic control of functional cargo P-gp siRNA that is significantly more stable than the "tail-like" TDN nanostructures. The stable and highly rigid 3D nanostructure of the siRNA-organized TDRN nanocages demonstrated a notable improvement in the stability of RNase A and mouse serum, as well as long-term storage stability for up to 4 weeks, as evidenced by this study. These biocompatible and multifunctional TDRN nanocarriers with gold nanocluster-assisted delivery (TDRN@Dox@AuNCp) are successfully used to achieve synergistic RNAi/Chemo-therapy in vitro and in vivo. This programmable TDRN drug delivery system, which integrates RNAi therapy and chemotherapy, offers a promising approach for treating multidrug-resistant tumors.

Defective Lamtor5 Leads to Autoimmunity by Deregulating v-ATPase and Lysosomal Acidification.

Despite accumulating evidence linking defective lysosome function with autoimmune diseases, how the catabolic machinery is regulated to maintain immune homeostasis remains unknown. Late endosomal/lysosomal adaptor, MAPK and mTOR activator 5 (Lamtor5) is a subunit of the Ragulator mediating mechanistic target of rapamycin complex 1 (mTORC1) activation in response to amino acids, but its action mode and physiological role are still unclear. Here it is demonstrated that Lamtor5 level is markedly decreased in peripheral blood mononuclear cells (PBMCs) of patients with systemic lupus erythematosus (SLE). In parallel, the mice with myeloid Lamtor5 ablation developed SLE-like manifestation. Impaired lysosomal function and aberrant activation of mTORC1 are evidenced in Lamtor5 deficient macrophages and PBMCs of SLE patients, accompanied by blunted autolysosomal pathway and undesirable inflammatory responses. Mechanistically, it is shown that Lamtor5 is physically associated with ATP6V1A, an essential subunit of vacuolar H+-ATPase (v-ATPase), and promoted the V0/V1 holoenzyme assembly to facilitate lysosome acidification. The binding of Lamtor5 to v-ATPase affected the lysosomal tethering of Rag GTPase and weakened its interaction with mTORC1 for activation. Overall, Lamtor5 is identified as a critical factor for immune homeostasis by intergrading v-ATPase activity, lysosome function, and mTOR pathway. The findings provide a potential therapeutic target for SLE and/or other autoimmune diseases.