The novel cereblon modulator CC-885 inhibits mitophagy via selective degradation of BNIP3L.

Mitophagy is a degradative pathway that mediates the degradation of the entire mitochondria, and defects in this process are implicated in many diseases including cancer. In mammals, mitophagy is mediated by BNIP3L (also known as NIX) that is a dual regulator of mitochondrial turnover and programmed cell death pathways. Acute myeloid leukemia (AML) cells with deficiency of BNIP3L are more sensitive to mitochondria-targeting drugs. But small molecular inhibitors for BNIP3L are currently not available. Some immunomodulatory drugs (IMiDs) have been proved by FDA for hematologic malignancies, however, the underlining molecular mechanisms are still elusive, which hindered the applications of BNIP3L inhibition for AML treatment. In this study we carried out MS-based quantitative proteomics analysis to identify the potential neosubstrates of a novel thalidomide derivative CC-885 in A549 cells. In total, we quantified 5029 proteins with 36 downregulated in CRBN+/+ cell after CC-885 administration. Bioinformatic analysis showed that macromitophagy pathway was enriched in the negative pathway after CC-885 treatment. We further found that CC-885 caused both dose- and time-dependent degradation of BNIP3L in CRBN+/+, but not CRBN-/- cell. Thus, our data uncover a novel role of CC-885 in the regulation of mitophagy by targeting BNIP3L for CRL4CRBN E3 ligase-dependent ubiquitination and degradation, suggesting that CC-885 could be used as a selective BNIP3L degradator for the further investigation. Furthermore, we demonstrated that CC-885 could enhance AML cell sensitivity to the mitochondria-targeting drug rotenone, suggesting that combining CC-885 and mitochondria-targeting drugs may be a therapeutic strategy for AML patients.

TGF-ß3 Induces Autophagic Activity by Increasing ROS Generation in a NOX4-Dependent Pathway.

Higher concentrations of reactive oxygen species (ROS) have been associated with epithelial cell damage, cell shedding, and airway hyperresponsiveness. Previous studies have indicated that transforming growth factor-beta (TGF-ß) mediates ROS production and NADPH oxidase (NOX) activity. In our previous study, we also observed that TGF-ß3 increases mucus secretion in airway epithelial cells in an autophagy-dependent fashion. Although it is well known that the relationship between ROS and autophagy is cell context-dependent, the exact mechanism of action remains unclear. The following study examined whether ROS act as upstream of autophagy activation in response to TGF-ß3 induction. Using an allergic inflammation mouse model induced by house dust mite (HDM), we observed elevated lung amounts of TGF-ß3 accompanied by increased ROS levels. And we found that ROS levels were elevated and NOX4 expression was increased in TGF-ß3-induced epithelial cells, while the lack of NOX4 in the epithelial cells could reduce ROS generation and autophagy-dependent MUC5AC expression treated with TGF-ß3. Furthermore, our studies demonstrated that the Smad2/3 pathway was involved in TGF-ß3-induced ROS generation by promoting NOX4 expression. The inhibition of ROS generation by N-Acetyl-L-cysteine (NAC) resulted in a decrease in mucus expression and autophagy activity in vivo as well as in vitro. Finally, TGF-ß3-neutralizing antibody significantly reduced the ROS generation, mucus expression, and autophagy activity and also decreased the phosphorylation of Smad2 and Smad3. Taken together, the obtained results revealed that persistent TGF-ß3 activation increased ROS levels in a NOX4-dependent pathway and subsequently induced autophagy as well as MUC5AC expression in the epithelial cells.

Functional screening and rational design of compounds targeting GPR132 to treat diabetes.

Chronic inflammation due to islet-residing macrophages plays key roles in the development of type 2 diabetes mellitus. By systematically profiling intra-islet lipid-transmembrane receptor signalling in islet-resident macrophages, we identified endogenous 9(S)-hydroxy-10,12-octadecadienoic acid-G-protein-coupled receptor 132 (GPR132)-Gi signalling as a significant contributor to islet macrophage reprogramming and found that GPR132 deficiency in macrophages reversed metabolic disorders in mice fed a high-fat diet. The cryo-electron microscopy structures of GPR132 bound with two endogenous agonists, N-palmitoylglycine and 9(S)-hydroxy-10,12-octadecadienoic acid, enabled us to rationally design both GPR132 agonists and antagonists with high potency and selectivity through stepwise translational approaches. We ultimately identified a selective GPR132 antagonist, NOX-6-18, that modulates macrophage reprogramming within pancreatic islets, decreases weight gain and enhances glucose metabolism in mice fed a high-fat diet. Our study not only illustrates that intra-islet lipid signalling contributes to islet macrophage reprogramming but also provides a broadly applicable strategy for the identification of important G-protein-coupled receptor targets in pathophysiological processes, followed by the rational design of therapeutic leads for refractory diseases such as diabetes.

[Study on the estrogen derivative marked by CdTe quantum dots].

Water-soluble CdTe quantum dots (QDs) stabilized by thioglycolic acid (TGA) with high quantum yield were synthesized. And the small biomolecule 17beta-amino-estradiol was marked successfully by CdTe QDs. The analysis of UV-Vis spectroscopy, fluorescence spectroscopy, infrared spectroscopy and inverted microscope photographs showed that the surface carboxyl of CdTe quantum dots conjugated with the amino of 17beta-amino-estradiol through the activation of N-hydroxysuccinimide. 17beta-amino-estradiol marked by CdTe QDs successfully provided an experimental basis for new drug screening model.

[Preparation and evaluation of a new xenogenic implant material].

OBJECTIVE: To prepare a new xenogenic material using patented biochemical techniques for tissue disposal and investigate its possibility to be used as implant materials. METHODS: The xenogenic implant materials were prepared by treatment of fresh porcine tendon with epoxy cross-linking fixation, antigen minimization procedures, mechanical enhancement by protein molecule modification and surface treatments. Histological and scanning electron microscopic observations were conducted, and physicochemical property assessment was carried out to determine the mechanical properties, protein contents, polyepoxy compound residual and stability of the material. The in vitro cytotoxicity of the material was tested in NCTC L929 cells, and the optical density of the cells at 24, 48, and 72 h of the treatments was determined to calculate the relative growth rate (RGR). RESULTS: Histological observation suggested that the xenogenic implant material consisted primarily of collagen without cell fragments. Scanning electron microscopy demonstrated homogeneous alignment of the collagen fibers in the material. The tensile strength of the material was 11-16 MPa, and the breaking elongation rate was 52%-67%; the protein contents was 94% with polyepoxy compound residual less than 5 microg/ml. The material maintained stable pH value in PBS. The L929 cells incubated with the biomaterials grew well with a relative growth rate over 89%. CONCLUSION: The new biomaterial has good physicochemical properties and good biocompatibility, and may served as a promising implant material.

[Effective expression of ribonuclease-onconase in Escherichia coli and assaying its cytotoxic potential].

Onconase, a ribonuclease purified from Rana pipiens oocytes, has cytotoxic activity against several tumor cell lines in vitro. With the characteristic of containing four pairs of disulfide bonds internal and N terminal sequence attributing mostly to its biological functions, it is difficult to obtain the active Onconase from Escherichia coli expression system with normal strategy. Here, we fused the cDNA coding for Onconase in frame with the pelB signal sequence in pET22b(+) expression vector. Onconase can be effectively expressed in inclusion body without additional residues at N terminal under the proper inducing condition. After refolding and purifying process, we can get the recombined Onconase which has a similar ribonuclease activity as the one isolated from oocytes. The recombined Onconase has a pronounced effect on proliferation of Hut-78 cells (IC50=0.5 micromol/L).