Obesity is associated with metabolic inflammation and endoplasmic reticulum (ER) stress, both of which promote metabolic disease progression. Adipose tissue macrophages (ATMs) are key players orchestrating metabolic inflammation, and ER stress enhances macrophage activation. However, whether ER stress pathways underlie ATM regulation of energy homeostasis remains unclear. Here, we identified inositol-requiring enzyme 1α (IRE1α) as a critical switch governing M1-M2 macrophage polarization and energy balance. Myeloid-specific IRE1α abrogation in Ern1; Lyz2-Cre mice largely reversed high-fat diet (HFD)-induced M1-M2 imbalance in white adipose tissue (WAT) and blocked HFD-induced obesity, insulin resistance, hyperlipidemia and hepatic steatosis. Brown adipose tissue (BAT) activity, WAT browning and energy expenditure were significantly higher in Ern1; Lyz2-Cre mice. Furthermore, IRE1α ablation augmented M2 polarization of macrophages in a cell-autonomous manner. Thus, IRE1α senses protein unfolding and metabolic and immunological states, and consequently guides ATM polarization. The macrophage IRE1α pathway drives obesity and metabolic syndrome through impairing BAT activity and WAT browning.

Herein is reported a convergent synthesis of isocombretastatins A, a novel class of potent antitubulin agents. These compounds having a 1,1-diarylethylene scaffold constitute the simplest isomers of natural Z-combretastatins A that are easy to synthesize without need to control the Z-olefin geometry. The discovery of isoCA-4 with biological activities comparable to that of CA-4 represents a major progress in this field.

We developed a new robust reduction-responsive polymersome based on the amphiphilic block copolymer PEG-SS-PAChol. The stability and robustness were achieved by the smectic physical cross-linking of cholesterol-containing liquid crystal polymer PAChol in the hydrophobic layer. The reduction-sensitivity was introduced by the disulfide bridge (-S-S-) that links the hydrophilic PEG block and the hydrophobic PAChol block. We used a versatile synthetic strategy based on atom transfer radical polymerization (ATRP) to synthesize the reduction-responsive amphiphilic block copolymers. The reductive cleavage of the disulfide bridge in the block copolymers was first evidenced in organic solution. The partial destruction of PEG-SS-PAChol polymersomes in the presence of a reducing agent was then demonstrated by cryo-electron microscopy. Finally, the calcein release from PEG-SS-PAChol polymersomes triggered by glutathione (GSH) was observed both in PBS suspension and in vitro inside the macrophage cells. High GSH concentrations (≥35 mM in PBS or artificially enhanced in macrophage cells by GSH-OEt pretreatment) and long incubation time (in the order of hours) were, however, necessary to get significant calcein release. These polymersomes could be used as drug carriers with very long circulation profiles and slow release kinetics.