Autophagy is a highly conserved intracellular catabolic process used to degrade cytoplasmic components. In recent years, it has attracted much attention because of its importance in the pathogenesis and targeted therapy of acute and chronic kidney disease. Autophagy plays an important role in maintaining renal homeostasis under physiological and pathological conditions. The study of conditional autophagy related gene knockout specific to various renal cells has gradually revealed the role of autophagy in renal diseases. Recent studies have found that autophagy deficiency may play a key role in different pathological states of the kidney. Activated autophagy shows cytoprotective function in both glomerulus and renal tubulointerstitium, suggesting that the up regulation of autophagy may become a potential therapeutic strategy. However, there is also contrary evidence that autophagy may be harmful, which poses a great challenge to the development of therapeutic strategies for up-regulated autophagy.

Hyaluronic acid (HA) is a natural ligand of tumor-targeted drug delivery systems (DDS) due to the relevant CD44 receptor overexpressed on tumor cell membranes. However, other HA receptors (HARE and LYVE-1) are also overexpressing in the reticuloendothelial system (RES). Therefore, polyethylene glycol (PEG) modification of HA-based DDS is necessary to reduce RES capture. Unfortunately, pegylation remarkably inhibits tumor cellular uptake and endosomal escapement, significantly compromising the antitumor efficacy. Herein, we developed a Dox-loaded HA-based transformable supramolecular nanoplatform (Dox/HCVBP) to overcome this dilemma. Dox/HCVBP contains a tumor extracellular acidity-sensitive detachable PEG shell achieved by a benzoic imine linkage. The and investigations further demonstrated that Dox/HCVBP could be in a "stealth" state at blood stream for a long circulation time due to the buried HA ligands and the minimized nonspecific interaction by PEG shell. However, it could transform into a "recognition" state under the tumor acidic microenvironment for efficient tumor cellular uptake due to the direct exposure of active targeting ligand HA following PEG shell detachment. Such a transformative concept provides a promising strategy to resolve the dilemma of natural ligand-based DDS with conflicting two processes of tumor cellular uptake and nonspecific biodistribution.