Caption: Autophagy is a type of cellular "housekeeping" that involves signaling, removal of debris, and recycling. Original watercolor painting by Stephen Kade based on a scientific design by Daniel J. Klionsky.

Whether a tree flourishes or is poisoned under the same rain (VEGFA stimulation) depends on where the rain falls (with full supply or severe shortage of phosphoinositide). See page 895-910 by Wencao Zhao et al. for details.

‘Nuwa mends the sky’ is a traditional Chinese myth where the goddess Nuwa smelted five colored-stones to patch up the sky and save all mankind. This story reflects how GV-971, a marine derived oligosaccharide, fills in the gap in the current Alzheimer's treatment via targeting a gut-brain axis. See page 787-803 by Xinyi Wang et al. for details.

The cover uses a Chinese historical allusion of “beans casted on the ground magically turn into soldiers” to depict the intra-tumoral heterogeneity in pancreatic ductal adenocarcinoma and the battle between tumor cells (soldiers with shields) and T cells (soldiers with swords). See page 725-738 by Junya Peng et al. for details.

The dimeric architecture of Tel1/ATM resembles a butterfly stretching out its wings. The symmetric dimer is in an inactive state, whereas the asymmetric structure is representative of the pathway toward activation. See page 655-665 by Jiyu Xin et al. for details.

The impact of intestinal microbes goes well beyond intestine. Molecular signals derived from intestinal microbes can prompt islet beta cells to secrete insulin in a Nod1-dependent manner. When bacteria speak, islet beta cells nod.See page 516-532 by Qin Zhang et al. for details.

An old saying from the ancient Chinese philosopher Zhuangzi (Zhuang-Tzu), “A frog in bottom of well doth not imagine sea, whilst an insect in summer doth not interpret ice”, can illustrate that hierarchical activation of AMPK is a matter of space and time. See page 460-473 by Yue Zong et al. for details.

The cover image illustrates how RNAi (terracotta warrior from Qin dynasty of China), as an "ancient" antiviral immunity mechanism, protects human neural progenitors (the wall) and brain organoids (beacon towers) from the invasion of Zika viruses. In antiviral RNAi, Dicer (the crossbow) produces viral siRNAs (the arrows) from viral dsRNA to specifically target and cleave viral genomic RNAs. Cover art is contributed by Dr. Yefei Li. See page 265-273 by Yan-Peng Xu et al. for details.

Dramatic oscillation of ovarian steroid hormones during pregnant stage leads to obvious morphological changes of mammary gland and endows luminal cells with unexpected plasticity. The cover image shows a few green sakura among clusters of cherry sakura on the tree, which resemble the scene of luminal-derived basal cells (LdBCs) on the mouse mammary gland ductal tree during pregnancy. See page 206-220 by Wenqian Song et al. for details.

Mammalian oocyte undergoes dramatic epigenetic and chromatin changes during its growth. To systematically dissect this process, Gu et al. performed integrative single-cell analysis of transcriptome, DNA methylome and chromatin accessibility in mouse oocytes. See page 110-123 by Chan Gu et al. for details.