Structure-guided engineering an (R)-transaminase from Mycobacterium neoaurum for efficient synthesis of chiral N-heterocyclic amines.

(R)-selective amine transaminases (R-ATAs) show considerable potential for the asymmetric synthesis of chiral drug intermediates. However, the low catalytic efficiency of natural R-ATAs toward bulky ketone substrates, such as N-heterocyclic compounds, severely limits its industrial application. In this study, five putative (R)-ATAs were mined from NCBI database, among which MnTA showed the highest activity for N-Boc-3-pyrrolidinone (1a) and N-Boc-3-piperidone (2a), and its crystal structure was performed.

Structure-based reshaping of a new ketoreductase from Sphingobacterium siyangense SY1 toward α-haloacetophenones.

Ketoreductases play an indispensable role in the asymmetric synthesis of chiral drug intermediates, and an in-depth understanding of their substrate selectivity can improve the efficiency of enzyme engineering. In this endeavor, a new short-chain dehydrogenase/reductase (SDR) SsSDR1 identified from Sphingobacterium siyangense SY1 by gene mining method was successfully cloned and functionally expressed in Escherichia coli. Its activity against halogenated acetophenones has been tested and the results illustrated that SsSDR1-WT exhibits high activity for 3,5-bis(trifluoromethyl)acetophenone (1f), an important precursor in the synthesis of aprepitant.

Application of Directed Evolution and Machine Learning to Enhance the Diastereoselectivity of Ketoreductase for Dihydrotetrabenazine Synthesis.

Biocatalysis is an effective approach for producing chiral drug intermediates that are often difficult to synthesize using traditional chemical methods. A time-efficient strategy is required to accelerate the directed evolution process to achieve the desired enzyme function. In this research, we evaluated machine learning-assisted directed evolution as a potential approach for enzyme engineering, using a moderately diastereoselective ketoreductase library as a model system.

Prognostic significance of a pathological response in metastatic lymph nodes of patients with gastric cancer who underwent neoadjuvant chemotherapy followed by surgery.

Purpose: To grade the pathological response of lymph nodes (LNs) to neoadjuvant chemotherapy (NAC) in patients with locally advanced gastric cancer (LAGC) and investigate its prognostic significance.

Methods: This retrospective study included 196 patients who underwent NAC, followed by radical gastrectomy for LAGC between January 2010 and October 2019. Pathological responses were evaluated based on the proportion of residual tumor cells within the tumor area in the primary tumor (PT) and LNs and included the following categories: 1a (0%), 1b (< 10%), 2 (10-50%), and 3 (> 50%).

The new N, N-diphenylpyridine-2,4-diamine deuterated derivatives as EGFR inhibitors to overcome C797S-mediated resistance.

A series of new deuterated and non-deuterated N, N-diphenylpyridine - 2,4-diamine derivatives were synthesized and evaluated as EGFR C797S-mediated resistance inhibitors. Most of these compounds exhibited potent antiproliferative activity against Baf3-EGFR and Baf3-EGFR cancel cell lines, with IC values in the nanomolar concentration range. Among them, compound 14l represented the most active compound with IC values of 8-11 nM.

SHP-1 Regulates CD8+ T Cell Effector Function but Plays a Subtle Role with SHP-2 in T Cell Exhaustion Due to a Stage-Specific Nonredundant Functional Relay.

SHP-1 (Src homology region 2 domain-containing phosphatase 1) is a well-known negative regulator of T cells, whereas its close homolog SHP-2 is the long-recognized main signaling mediator of the PD-1 inhibitory pathway. However, recent studies have challenged the requirement of SHP-2 in PD-1 signaling, and follow-up studies further questioned the alternative idea that SHP-1 may replace SHP-2 in its absence. In this study, we systematically investigate the role of SHP-1 alone or jointly with SHP-2 in CD8+ T cells in a series of gene knockout mice.

Tracking the extracellular and intracellular antibiotic resistance genes across whole year in wastewater of intensive dairy farm.

Monitoring the annual variation of antibiotic resistance genes (ARGs) in livestock wastewater is important for determining the high-risk period of transfer and spread of animal-derived antibiotic resistance into the environment. However, the knowledge regarding the variation patterns of ARGs, especially intracellular ARGs (iARGs) and extracellular ARGs (eARGs), over time in livestock wastewater is still unclear. Herein, we conducted a year-round study to trace the profiles of ARGs at a Chinese-intensive dairy farm, focusing on the shifts observed in different months.

MHC class II regulation of CD8 T cell tolerance and implications in autoimmunity and cancer immunotherapy.

Major histocompatibility complex (MHC) class II-reactive CD8 T cells are found in humans and animals, but little is known about their identity, development, and function. In this study, we discover a group of CD8 T cells reactive to both MHC class I and II molecules in MHC class II-deficient mice. We clone their T cell receptors (TCRs) and analyze their development and function.

Spatial proteomics of immune microenvironment in nonalcoholic steatohepatitis-associated hepatocellular carcinoma.

Background And Aims: NASH-HCC is inherently resistant to immune checkpoint blockade, but its tumor immune microenvironment is largely unknown.

Approach And Results: We applied the imaging mass cytometry to construct a spatially resolved single-cell atlas from the formalin-fixed and paraffin-embedded tissue sections from patients with NASH-HCC, virus-HCC (HBV-HCC and HCV-HCC), and healthy donors. Based on 35 biomarkers, over 750,000 individual cells were categorized into 13 distinct cell types, together with the expression of key immune functional markers.

Synthesis and evaluation of sulfonamide derivatives targeting EGFR mutations and ALK rearrangement as anticancer agents.

Fourteen new compounds bearing sulfonamide groups that target EGFRT mutations and ALK rearrangement were synthesized and evaluated as dual-target tumor inhibitors. The study on the anti-proliferation activity on cancer cells showed that the sulfonamide derivative with pyrimidine nucleus had much better activities compared with those with quinazoline nucleus. Among them, compound 19e exhibited excellent activity against H1975 cancer cell lines (EGFR high express) and H2228 cells (ALK rearrangement) with the IC values of 0.

Themis suppresses the effector function of CD8 T cells in acute viral infection.

CD8 T cells play a central role in antiviral immune responses. Upon infection, naive CD8 T cells differentiate into effector cells to eliminate virus-infected cells, and some of these effector cells further differentiate into memory cells to provide long-term protection after infection is resolved. Although extensively investigated, the underlying mechanisms of CD8 T-cell differentiation remain incompletely understood.

A novel NADH-dependent leucine dehydrogenase for multi-step cascade synthesis of L-phosphinothricin.

L-Phosphinothricin (L-PPT) is the effective constituent in racemic PPT (a high-efficiency and broad-spectrum herbicide), and the exploitation of green and sustainable synthesis route for L-PPT has always been the focus in pesticide industry. In recent years, "one-pot, two-step" enzyme-mediated cascade strategy is a mainstream pathway to obtain L-PPT. Herein, RgDAAO and BsLeuDH were applied to expand "one-pot, two-step" process.

Revealing the evolution of the tumor immune microenvironment in follicular lymphoma patients progressing within 24 months using single-cell imaging mass cytometry.

Background: Patients with follicular lymphoma (FL) who experience disease progression within 24 months (POD24) have inferior outcomes. The tumor immune microenvironment (TIME) plays a crucial role in pathogenesis and progression of follicular lymphoma (FL). However, TIME evolution during progression of disease within 24 months (POD24) is elusive.

Ketoreductase Catalyzed (Dynamic) Kinetic Resolution for Biomanufacturing of Chiral Chemicals.

Biocatalyzed asymmetric reduction of ketones is an environmentally friendly approach and one of the most cost-effective routes for producing chiral alcohols. In comparison with the well-studied reduction of prochiral ketones to generate chiral alcohols with one chiral center, resolution of racemates by ketoreductases (KREDs) to produce chiral compounds with at least two chiral centers is also an important strategy in asymmetric synthesis. The development of protein engineering and the combination with chemo-catalysts further enhanced the application of KREDs in the efficient production of chiral alcohols with high stereoselectivity.

Oncolytic virus expressing PD-1 inhibitors activates a collaborative intratumoral immune response to control tumor and synergizes with CTLA-4 or TIM-3 blockade.

Background: Oncolytic viruses (OVs) are capable to inflame the tumor microenvironment (TME) and elicit infiltrating tumor-specific T cell responses. However, OV treatment negatively alters the cancer-immune set point in tumors to attenuate the antitumor immune response, which suggests the necessity of dissecting the immune landscape of the virus-treated tumors and developing novel strategies to maximize the potential of OVs. The aim of this study is to investigate the effect of the single-chain variable fragment (scFv)-armed OVs targeting PD-1 on the TME, and ultimately overcome localized immunosuppression to sensitize tumors to immunotherapies.

Amorphous zirconium metal-organic frameworks assembled from mixed porphyrins as solvent-free catalysts for Knoevenagel condensation.

Three mixed porphyrins, icpp (1-3), were synthesized the reactions of 4-formylbenzoic acid and 4-imidazolecarboxaldehyde, and then five amorphous or crystalline Zr-MOFs-SPUZ (1-5) were obtained from icpp (1-3), timp and tcpp, respectively. The catalytic activities of the synthesized porphyrins and MOFs were studied on the Knoevenagel condensation of aldehydes and malononitrile under solvent-free conditions. Among them, amorphous MOF SPUZ-1 showed the highest catalytic activity.

Efficient synthesis of an apremilast precursor and chiral β-hydroxy sulfones ketoreductase-catalyzed asymmetric reduction.

Ketoreductase (KRED)-catalyzed asymmetric reduction of prochiral ketones is an attractive method to synthesize chiral alcohols. Herein, two KREDs LfSDR1-V186A/E141I and CgKR1-F92I with complementary stereopreference were identified towards reduction of apremilast prochiral ketone intermediate 1a. LfSDR1-V186A/E141I exhibited >99% conversion and 99.

Glycogen synthase kinase 3 drives thymocyte egress by suppressing β-catenin activation of Akt.

Molecular pathways controlling emigration of mature thymocytes from thymus to the periphery remain incompletely understood. Here, we show that T cell–specific ablation of glycogen synthase kinase 3 (GSK3) led to severely impaired thymic egress. In the absence of GSK3, β-catenin accumulated in the cytoplasm, where it associated with and activated Akt, leading to phosphorylation and degradation of Foxo1 and downregulation of Klf2 and S1P expression, thereby preventing emigration of thymocytes.

IFN-γ-dependent NK cell activation is essential to metastasis suppression by engineered Salmonella.

Metastasis accounts for 90% of cancer-related deaths and, currently, there are no effective clinical therapies to block the metastatic cascade. A need to develop novel therapies specifically targeting fundamental metastasis processes remains urgent. Here, we demonstrate that Salmonella YB1, an engineered oxygen-sensitive strain, potently inhibits metastasis of a broad range of cancers.

Old yellow enzymes: structures and structure-guided engineering for stereocomplementary bioreduction.

Since the first discovery of old yellow enzyme 1 (OYE1) from Saccharomyces pastorianus in 1932, biocatalytic asymmetric reduction of activated alkenes by OYEs has become a valuable reaction in organic synthesis. To access stereocomplementary C=C-bond bioreduction, the mining of novel OYEs and especially the protein engineering of existing OYEs have been performed, which successfully achieved the stereocomplementary reduction in several cases and further raise the potential of applications. In this review, we analyzed the structures, active sites, and substrate recognition of OYEs, which are the bases for their substrate specificity and stereospecificity.

Apatinib exhibits cytotoxicity toward leukemia cells by targeting VEGFR2-mediated prosurvival signaling and angiogenesis.

Objective: Vascular permeability contributes to disease progression and drug resistance in hematological malignancies, including AML. Thus, targeting angiogenic signaling is a promising treatment strategy, especially for relapsed and resistant AML. The aim of this study was to evaluate the efficacy of apatinib, a novel receptor tyrosine kinase inhibitor that selectively targets VEGFR2.

A Carrier Strategy for Mass Cytometry Analysis of Small Numbers of Cells.

The recent launch of mass cytometry or cytometry by time of flight (CyTOF) has revolutionized flow cytometry. Similar to fluorescence flow cytometry, a key challenge for CyTOF is to analyze samples of limited amount or very rare cell populations under various experimental settings. Here we describe a carrier strategy that significantly reduces the required sample amount without losing analytical resolution.

Remote ischemic post-conditioning protects against myocardial ischemia/reperfusion injury by inhibiting the Rho-kinase signaling pathway.

The aim of the present study was to observe the effect of Rho-kinase on remote ischemic post-conditioning (RIPostC) and explore the underlying mechanisms. Male Sprague Dawley rats (n=32) were randomly distributed into four groups: Sham group, ischemia/reperfusion (I/R) group, RIPostC group and I/R with fasudil group (I/R+Fas). Infarction size was detected by triphenyltetrazolium chloride staining.