Haibin Chen

(R)-1, 3-Butanediol (1, 3-BDO) is an important intermediate in the synthesis of aromatics, pheromones, insecticides, and beta-lactam antibiotics. The ChKRED20 is a robust NADH-dependent ketoreductase identified from Chryseobacterium sp. CA49. We obtained a ChKRED20 mutant (M12) through directed evolutionary screening of ChKRED20, the mutant with significantly improved activity to asymmetrically reduce 4-hydroxy-2-butanone (4H2B) to (R)-1, 3-BDO. So far, both ChKRED20 and its mutants have been expressed in intracellular in E. coli, the process of purification after intracellular expression is complicated, which leads to high cost. Here, we expressed M12 by constructing multicopy expression strains in P. pastoris, and the target protein yield was 302 mg/L in shake-flask fermentation and approximately 3.5 g/L in high-density fermentation. The recombinant M12 showed optimal enzyme activity at 30 °C and had high activity within a broad pH range of 6.0–8.0, and also showed high thermal stability. The recombinant M12 was further used for the reduction of 4H2B to (R)-1, 3-BDO, and 98.9% yield was achieved at 4540 mM 4H2B. The crude M12 enzyme extract was found to catalyze the bioreductive production of (R)-1, 3-BDO with excellent stereoselectivity (ee > 99%) and meet the production requirements. Our research shows that the M12 mutant can be used for the synthesis of (R)-1, 3-BDO, and the P. pastoris expression system is an ideal platform for the large-scale, low-cost preparation of ChKRED20 or its mutants, which may have applications in industrial settings.

Halohydrin dehalogenases (HHDHs) have demonstrated significant potential as biocatalysts for synthesizing industrial heterocyclic compounds and chiral alkanolamines from aromatic substrates with NaOCN that are not feasible through chemosynthesis. To further study the HHDH reaction in real industrial applications, a diverse panel of HHDHs has been screened for their ability to convert aliphatic cyclohexene oxide. By using the best HHDH variant in form of a whole cell biocatalyst, a novel chemical process, regulated by the cascaded chemoenzymatic reactions for pilot‐scale ring‐opening reactions, has been successfully developed. Using the best HHDH hit in whole‐cell form provides a viable bio‐catalytic approach for the synthesis of related fine chemicals. Our research provides a promising strategy for scaling up non‐native ring‐opening reactions from the laboratory to industrial applications.

Background: Cancer-associated fibroblasts (CAFs) represent the predominant stromal component within the tumour microenvironment (TME), exhibiting considerable heterogeneity and plasticity that significantly impact immune response and metabolic reprogramming within the TME, thereby influencing tumour progression. Consequently, investigating CAFs is of utmost importance. The objective of this study is to employ bibliometric analysis in order to evaluate the current state of research on CAFs and predict future areas of research and emerging trends.Methods: Conduct a comprehensive search for scholarly publications within the Web of Science Core Collection database, encompassing the time period from January 1, 2001, to December 31, 2022. Apply VOSviewer, CiteSpace, R software and Microsoft Excel for bibliometric analysis and visualisation.Results: This study involved a comprehensive analysis of 5,925 publications authored by 33,628 individuals affiliated with 4,978 institutions across 79 countries/regions. These publications were published in 908 journals, covering 14,495 keywords and 203,947 references. Notably, there was a significant increase in articles published between 2019 and 2022. China had the highest count of articles, while the United States emerged as the most frequently cited country. The primary research institutions in this field were Shanghai Jiao Tong University, Harvard University, and the University of Texas MD Anderson Cancer Center. Sotgia, Federica and Lisanti, Michael P from the University of Manchester, and Martinet, Wim from the University of Antwerp were the most prolific and highly cited authors. The journal Cancers had the highest number of publications, while Cancer Research was the most frequently cited journal. Molecular, biology, immunology, medicine and genetics were the main research disciplines in the field of CAFs. Key directions in CAFs research encompassed the study of transforming growth factor-β, Fibroblast Activation Protein, breast cancer, as well as growth and metastasis. The findings from the analysis of keyword co-occurrence and literature co-citation have revealed several emerging hotspots and trends within the field of CAFs. These include STAT3, multidrug resistance, pancreatic ductal adenocarcinoma, pan-cancer analysis, preclinical evaluation, ionizing radiation, and gold nanoparticles.Conclusion: Targeting CAFs is anticipated to be a novel and effective strategy for cancer treatment. This study provides a comprehensive overview of the existing research on CAFs from 2001 to 2022, utilizing bibliometric analysis. The study identified the prominent areas of investigation and anticipated future research directions, with the aim of providing valuable insights and recommendations for future studies in the field of CAFs.

(2R,4R)‐Pentanediol is an interesting precursor for the synthesis of chiral ligands. A ketoreductase (KRED) was employed for the asymmetric reduction of acetylacetone to this diol. Biocatalysis often suffers from low concentrations of hydrophobic substrates and low stability of the enzyme in unconventional media. Here, we present an engineered KRED variant applicable in a neat substrate system, including upscaling to the multi‐liter scale and downstream processing (DSP). Our engineered KRED applied in a neat substrate system is a powerful technique for the synthesis of chiral diols yielding product concentrations of 208 g L⁻¹.

To investigate the efficacy of celastrol treatment of hepatocellular carcinoma (HCC) cells in vitro and in vivo and to propose a mechanism of action. A human HepG2 liver cancer cell line and a xenograft tumor model were used to investigate the effects of celastrol on HCC in vitro and in vivo. A CCK-8 kit was used to detect cell viability. Flow cytometry and terminal-deoxynucleoitidyl transferase mediated nick end labeling staining were used to detect apoptosis. Western blotting and immunohistochemistry were used to detect the expression of cleaved-caspase-3, cleaved-caspase-8, cleaved-caspase-9, cleaved-PARP, mammalian target of rapamycin (mTOR), and p-mTOR. Hematoxylin-eosin staining was used to observe the tissue morphology. Celastrol decreased the viability of HepG2 cells and induced apoptosis. Western blot assays indicated that celastrol up-regulated cleaved-caspase-3, cleaved-caspase-8, cleaved-caspase-9, and cleaved-PARP by inhibiting the phosphorylation of mTOR in HepG2 cells. Moreover, celastrol inhibited the tumor growth in a xenograft model. Celastrol also induced caspase-dependent apoptosis (up-regulation of cleaved-caspase- 3, -8, -9, and cleaved-PARP) and inhibited the activation of mTOR in vivo. Celastrol induces caspase-dependent apoptosis in HCC cells by inhibiting the activation of mTOR.

Growth differentiation factor 15 (GDF15; also known as MIC-1) is a divergent member of the TGF-β superfamily and is associated with body-weight regulation in humans and rodents. However, the cognate receptor of GDF15 is unknown. Here we show that GDF15 binds specifically to GDNF family receptor α-like (GFRAL) with high affinity, and that GFRAL requires association with the coreceptor RET to elicit intracellular signaling in response to GDF15 stimulation. We also found that GDF15-mediated reductions in food intake and body weight of mice with obesity were abolished in GFRAL-knockout mice. We further found that GFRAL expression was limited to hindbrain neurons and not present in peripheral tissues, which suggests that GDF15–GFRAL-mediated regulation of food intake is by a central mechanism. Lastly, given that GDF15 did not increase energy expenditure in treated mice with obesity, the anti-obesity actions of the cytokine are likely driven primarily by a reduction in food intake.