Inherent Capability of Self-Assembling Nanostructures in Specific Proteasome Activation for Cancer Cell Pyroptosis.

Understanding the direct interaction of nanostructures per se with biological systems is important for biomedical applications. However, whether nanostructures regulate biological systems by targeting specific cellular proteins remains largely unknown. In the present work, self-assembling nanomicelles are constructed using small-molecule oleanolic acid (OA) as a molecular template. Unexpectedly, without modifications by functional ligands, OA nanomicelles significantly activate cellular proteasome function by directly binding to 20S proteasome subunit alpha 6 (PSMA6). Mechanism study reveals that OA nanomicelles interact with PSMA6 to dynamically modulate its N-terminal domain conformation change, thereby controlling the entry of proteins into 20S proteasome. Subsequently, OA nanomicelles accelerate the degradation of several crucial proteins, thus potently driving cancer cell pyroptosis. For translational medicine, OA nanomicelles exhibit a significant anticancer potential in tumor-bearing mouse models and stimulate immune cell infiltration. Collectively, this proof-of-concept study advances the mechanical understanding of nanostructure-guided biological effects via their inherent capacity to activate proteasome.

[Anti-pneumonia targets and mechanism of Xiaoer Xiaoji Zhike Oral Liquid].

This study aims to identify the anti-pneumonia targets of Xiaoer Xiaoji Zhike Oral Liquid(XXZL) with "target fishing" strategy and investigate the related signaling pathways, thereby clarifying the anti-pneumonia mechanism of XXZL. To be specific, the magnetic nanoparticles cross-linked with XXZL extract were prepared based on the photochemical activity of benzophenone, which were then used to capture the target proteins from the lysate of tissue with lipopolysaccharide(LPS)-induced pneumonia in mice. Then, the target proteins were identified by liquid chromatography-tandem mass spectrometry(LC-MS/MS). The signaling pathways and interactions of target proteins were explored with KEGG and STRING analysis on Cytoscape, and the possible biological functions of the target proteins were verified by immunohistochemistry(IHC) and RT-PCR. The result showed that LC-MS/MS identified 62 potential anti-pneumonia targets of XXZL in the lungs. The targets were involved in Ras signaling pathway, mitophagy, leukocyte transendothelial migration, mitogen-activated protein kinase(MAPK) signaling pathway, platelet activation, and actomyosin structure organization, which were closely related to inflammation, pulmonary microcirculation, pulmonary fibrosis, and energy metabolism. XXZL up-regulated the content of CD31, and heat shock protein 60(HSP60) and ATP5 b mRNA expression, down-regulated interleukin-6(IL-6), tumor necrosis factor-α(TNF-α), COL1 A1 content, and alleviated fibrosis, which suggested the obvious effects of XXZL such as anti-inflammation, pulmonary microcirculation improvement, pulmonary fibrosis inhibition, and energy metabolism regulation. This study explained the anti-pneumonia mechanism of XXZL from targets, which can serve as a reference for the clinical application of the prescription.

Lycorine promotes IDH1 acetylation to induce mitochondrial dynamics imbalance in colorectal cancer cells.

Isocitrate dehydrogenase (IDH) 1 and 2, as essential enzymes in energy metabolism, contribute to the survival and drug resistance of a variety of solid tumors, especially for colorectal cancer (CRC). However, the underlying molecular mechanism still remains unclear. In this study, IDH1 was identified as a crucial cellular target of a natural-derived anti-CRC small molecule lycorine, using the unbiased thermal proteome profiling (TPP) strategy. We found that lycorine directly targeted a unique C-terminal domain of IDH1, and disrupted IDH1 interaction with deacetylase sirtuin 1 (SIRT1), thereby significantly promoting IDH1 acetylation modification. Then, lycorine noticeably triggered oxidative stress in CRC cells to cause mitochondrial membranes injury, and subsequently facilitated mitochondrial fission. Specific knockdown of IDH1 or SIRT1 markedly aggrieved lycorine-mediated oxidative stress and mitochondrial fragmentation in CRC cells. Furthermore, the combination of lycorine and sirtuins blocker nicotinamide (NAM) exhibited a synergic therapeutic effect in CRC cells. Collectively, our results reveal that IDH1 may serve as a promising therapeutic target for CRC via pharmacologically driving oxidative stress-dependent mitochondrial dynamics imbalance.

Allosteric Activation of Transglutaminase 2 via Inducing an "Open" Conformation for Osteoblast Differentiation.

Osteoblasts play an important role in the regulation of bone homeostasis throughout life. Thus, the damage of osteoblasts can lead to serious skeletal diseases, highlighting the urgent need for novel pharmacological targets. This study introduces chemical genetics strategy by using small molecule forskolin (FSK) as a probe to explore the druggable targets for osteoporosis. Here, this work reveals that transglutaminase 2 (TGM2) served as a major cellular target of FSK to obviously induce osteoblast differentiation. Then, this work identifies a previously undisclosed allosteric site in the catalytic core of TGM2. In particular, FSK formed multiple hydrogen bonds in a saddle-like domain to induce an "open" conformation of the ß-sandwich domain in TGM2, thereby promoting the substrate protein crosslinks by incorporating polyamine. Furthermore, this work finds that TGM2 interacted with several mitochondrial homeostasis-associated proteins to improve mitochondrial dynamics and ATP production for osteoblast differentiation. Finally, this work observes that FSK effectively ameliorated osteoporosis in the ovariectomy mice model. Taken together, these findings show a previously undescribed pharmacological allosteric site on TGM2 for osteoporosis treatment, and also provide an available chemical tool for interrogating TGM2 biology and developing bone anabolic agent.

Carbon Quantum Dots-Based Nanozyme from Coffee Induces Cancer Cell Ferroptosis to Activate Antitumor Immunity.

Carbon quantum dots (CQDs) offer huge potential due to their enzymatic properties as compared to natural enzymes. Thus, discovery of CQDs-based nanozymes with low toxicity from natural resources, especially daily food, implies a promising direction for exploring treatment strategies for human diseases. Here, we report a CQDs-based biocompatible nanozyme prepared from chlorogenic acid (ChA), a major bioactive natural product from coffee. We found that ChA CQDs exhibited obvious GSH oxidase-like activities and subsequently promoted cancer cell ferroptosis by perturbation of GPX4-catalyzed lipid repair systems. In vivo, ChA CQDs dramatically suppressed the tumor growth in HepG2-tumor-bearing mice with negligible side toxicity. Particularly, in hepatoma H22-bearing mice, ChA CQDs recruited massive tumor-infiltrating immune cells including T cells, NK cells, and macrophages, thereby converting "cold" to "hot" tumors for activating systemic antitumor immune responses. Taken together, our study suggests that natural product-derived CQDs from coffee can serve as biologically safe nanozymes for anticancer therapeutics and may aid the development of nanotechnology-based immunotherapeutic.