Apoptotic extracellular vesicles are metabolized regulators nurturing the skin and hair.

Over 300 billion of cells die every day in the human body, producing a large number of endogenous apoptotic extracellular vesicles (apoEVs). Also, allogenic stem cell transplantation, a commonly used therapeutic approach in current clinical practice, generates exogenous apoEVs. It is well known that phagocytic cells engulf and digest apoEVs to maintain the body's homeostasis. In this study, we show that a fraction of exogenous apoEVs is metabolized in the integumentary skin and hair follicles. Mechanistically, apoEVs activate the Wnt/ß-catenin pathway to facilitate their metabolism in a wave-like pattern. The migration of apoEVs is enhanced by treadmill exercise and inhibited by tail suspension, which is associated with the mechanical force-regulated expression of DKK1 in circulation. Furthermore, we show that exogenous apoEVs promote wound healing and hair growth via activation of Wnt/ß-catenin pathway in skin and hair follicle mesenchymal stem cells. This study reveals a previously unrecognized metabolic pathway of apoEVs and opens a new avenue for exploring apoEV-based therapy for skin and hair disorders.

A clickable AIEgen for visualization of macrophage-microbe interaction.

Visualization of immunocyte-microbe interaction is of great importance to reveal the physiological role and working mechanism of innate and adaptive immune system. The lack of rapid and stable microbial labeling platform and insufficient understanding of macrophage-microbe interaction may delay precautions that could be made. In this contribution, a clickable AIEgen, CDPP-NCS, containing a cationic pyridinium moiety for targeting bacteria and an isothiocyanate moiety for covalently bonding with amine groups, is successfully developed. With the advantages of excellent photostability and rapid bioconjugation with amine groups on the bacterial envelope, the processes of macrophage-bacterium interactions with subcellular resolution has been successfully captured using this clickable AIE probe. Therefore, the new clickable AIEgen is a powerful tool to study the interaction between cell and bacterium.