Photocatalyzed Enantioselective Functionalization of C(sp3)-H Bonds.

Owing to its diverse activation processes including single-electron transfer (SET) and hydrogen-atom transfer (HAT), visible-light photocatalysis has emerged as a sustainable and efficient platform for organic synthesis. These processes provide a powerful avenue for the direct functionalization of C(sp3)-H bonds under mild conditions. Over the past decade, there have been remarkable advances in the enantioselective functionalization of the C(sp3)-H bond via photocatalysis combined with conventional asymmetric catalysis. Herein, we summarize the advances in asymmetric C(sp3)-H functionalization involving visible-light photocatalysis and discuss two main pathways in this emerging field: (a) SET-driven carbocation intermediates are followed by stereospecific nucleophile attacks; and (b) photodriven alkyl radical intermediates are further enantioselectively captured by (i) chiral π-SOMOphile reagents, (ii) stereoselective transition-metal complexes, and (iii) another distinct stereoscopic radical species. We aim to summarize key advances in reaction design, catalyst development, and mechanistic understanding, to provide new insights into this rapidly evolving area of research.

Semiautomated design and soluble expression of a chimeric antigen TbpAB01 from Glaesserella parasuis.

Pathogenic bacterial membrane proteins (MPs) are a class of vaccine and antibiotic development targets with widespread clinical application. However, the inherent hydrophobicity of MPs poses a challenge to fold correctly in living cells. Herein, we present a comprehensive method to improve the soluble form of MP antigen by rationally designing multi-epitope chimeric antigen (ChA) and screening two classes of protein-assisting folding element. The study uses a homologous protein antigen as a functional scaffold to generate a ChA possessing four epitopes from transferrin-binding protein A of Glaesserella parasuis. Our engineered strain, which co-expresses P17 tagged-ChA and endogenous chaperones groEL-ES, yields a 0.346 g/L highly soluble ChA with the property of HPS-positive serum reaction. Moreover, the protein titer of ChA reaches 4.27 g/L with >90% soluble proportion in 5-L bioreactor, which is the highest titer reported so far. The results highlight a timely approach to design and improve the soluble expression of MP antigen in industrially viable applications.

Anemoside B4, a new pyruvate carboxylase inhibitor, alleviates colitis by reprogramming macrophage function.

OBJECTIVES: Colitis is a global disease usually accompanied by intestinal epithelial damage and intestinal inflammation, and an increasing number of studies have found natural products to be highly effective in treating colitis. Anemoside B4 (AB4), an abundant saponin isolated from Pulsatilla chinensis (Bunge), which was found to have strong anti-inflammatory activity. However, the exact molecular mechanisms and direct targets of AB4 in the treatment of colitis remain to be discovered. METHODS: The anti-inflammatory activities of AB4 were verified in LPS-induced cell models and 2, 4, 6-trinitrobenzene sulfonic (TNBS) or dextran sulfate sodium (DSS)-induced colitis mice and rat models. The molecular target of AB4 was identified by affinity chromatography analysis using chemical probes derived from AB4. Experiments including proteomics, molecular docking, biotin pull-down, surface plasmon resonance (SPR), and cellular thermal shift assay (CETSA) were used to confirm the binding of AB4 to its molecular target. Overexpression of pyruvate carboxylase (PC) and PC agonist were used to study the effects of PC on the anti-inflammatory and metabolic regulation of AB4 in vitro and in vivo. RESULTS: AB4 not only significantly inhibited LPS-induced NF-κB activation and increased ROS levels in THP-1 cells, but also suppressed TNBS/DSS-induced colonic inflammation in mice and rats. The molecular target of AB4 was identified as PC, a key enzyme related to fatty acid, amino acid and tricarboxylic acid (TCA) cycle. We next demonstrated that AB4 specifically bound to the His879 site of PC and altered the protein's spatial conformation, thereby affecting the enzymatic activity of PC. LPS activated NF-κB pathway and increased PC activity, which caused metabolic reprogramming, while AB4 reversed this phenomenon by inhibiting the PC activity. In vivo studies showed that diisopropylamine dichloroacetate (DADA), a PC agonist, eliminated the therapeutic effects of AB4 by changing the metabolic rearrangement of intestinal tissues in colitis mice. CONCLUSION: We identified PC as a direct cellular target of AB4 in the modulation of inflammation, especially colitis. Moreover, PC/pyruvate metabolism/NF-κB is crucial for LPS-driven inflammation and oxidative stress. These findings shed more light on the possibilities of PC as a potential new target for treating colitis.

Transcriptional regulation and post-translational modifications in the glycolytic pathway for targeted cancer therapy.

Cancer cells largely rely on aerobic glycolysis or the Warburg effect to generate essential biomolecules and energy for their rapid growth. The key modulators in glycolysis including glucose transporters and enzymes, e.g. hexokinase 2, enolase 1, pyruvate kinase M2, lactate dehydrogenase A, play indispensable roles in glucose uptake, glucose consumption, ATP generation, lactate production, etc. Transcriptional regulation and post-translational modifications (PTMs) of these critical modulators are important for signal transduction and metabolic reprogramming in the glycolytic pathway, which can provide energy advantages to cancer cell growth. In this review we recapitulate the recent advances in research on glycolytic modulators of cancer cells and analyze the strategies targeting these vital modulators including small-molecule inhibitors and microRNAs (miRNAs) for targeted cancer therapy. We focus on the regulation of the glycolytic pathway at the transcription level (e.g., hypoxia-inducible factor 1, c-MYC, p53, sine oculis homeobox homolog 1, N6-methyladenosine modification) and PTMs (including phosphorylation, methylation, acetylation, ubiquitination, etc.) of the key regulators in these processes. This review will provide a comprehensive understanding of the regulation of the key modulators in the glycolytic pathway and might shed light on the targeted cancer therapy at different molecular levels.

Organic photoredox catalyzed C(sp3)-H functionalization of saturated aza-heterocycles via a cross-dehydrogenative coupling reaction.

Herein we present a novel protocol to access α-functionalized saturated aza-heterocycles, and a variety of nucleophilic groups, such as indole, naphthol, phenol, pyrrole, furyl, nitromethyl, and cyano, could be easily installed into saturated aza-heterocycles. Furthermore, a range of biologically valuable 3,3'-diindolylmethane derivatives could also be readily accessed under mild photocatalytic conditions.

Hederacoside C ameliorates colitis via restoring impaired intestinal barrier through moderating S100A9/MAPK and neutrophil recruitment inactivation.

Hederacoside C (HSC) has attracted much attention as a novel modulator of inflammation, but its anti-inflammatory mechanism remains elusive. In the present study, we investigated how HSC attenuated intestinal inflammation in vivo and in vitro. HSC injection significantly alleviated TNBS-induced colitis by inhibiting pro-inflammatory cytokine production and colonic epithelial cell apoptosis, and partially restored colonic epithelial cell proliferation. The therapeutic effect of HSC injection was comparable to that of oral administration of mesalazine (200 mg·kg-1·d-1, i.g.). In LPS-stimulated human intestinal epithelial Caco-2 cells, pretreatment with HSC (0.1, 1, 10 µM) significantly inhibited activation of MAPK/NF-κB and its downstream signaling pathways. Pretreatment with HSC prevented LPS-induced TLR4 dimerization and MyD88 recruitment in vitro. Quantitative proteomic analysis revealed that HSC injection regulated 18 proteins in the colon samples, mainly clustered in neutrophil degranulation. Among them, S100A9 involved in the degranulation of neutrophils was one of the most significantly down-regulated proteins. HSC suppressed the expression of S100A9 and its downstream genes including TLR4, MAPK, and NF-κB axes in colon. In Caco-2 cells, recombinant S100A9 protein activated the MAPK/NF-κB signaling pathway and induced inflammation, which were ameliorated by pretreatment with HSC. Notably, HSC attenuated neutrophil recruitment and degranulation as well as S100A9 release in vitro and in vivo. In addition, HSC promoted the expression of tight junction proteins and repaired the epithelial barrier via inhibiting S100A9. Our results verify that HSC ameliorates colitis via restoring impaired intestinal barrier through moderating S100A9/MAPK and neutrophil recruitment inactivation, suggesting that HSC is a promising therapeutic candidate for colitis.

Inhibition of USP10 induces myeloma cell apoptosis by promoting cyclin D3 degradation.

The cell cycle regulator cyclin D3 (CCND3) is highly expressed in multiple myeloma (MM) and it promotes MM cell proliferation. After a certain phase of cell cycle, CCND3 is rapidly degraded, which is essential for the strict control of MM cell cycle progress and proliferation. In the present study, we investigated the molecular mechanisms regulating CCND3 degradation in MM cells. By utilizing affinity purification-coupled tandem mass spectrometry, we identified the deubiquitinase USP10 interacting with CCND3 in human MM OPM2 and KMS11 cell lines. Furthermore, USP10 specifically prevented CCND3 from K48-linked polyubiquitination and proteasomal degradation, therefore enhancing its activity. We demonstrated that the N-terminal domain (aa. 1-205) of USP10 was dispensable for binding to and deubiquitinating CCND3. Although Thr283 was important for CCND3 activity, it was dispensable for CCND3 ubiquitination and stability modulated by USP10. By stabilizing CCND3, USP10 activated the CCND3/CDK4/6 signaling pathway, phosphorylated Rb, and upregulated CDK4, CDK6 and E2F-1 in OPM2 and KMS11 cells. Consistent with these findings, inhibition of USP10 by Spautin-1 resulted in accumulation of CCND3 with K48-linked polyubiquitination and degradation that synergized with Palbociclib, a CDK4/6 inhibitor, to induce MM cell apoptosis. In nude mice bearing myeloma xenografts with OPM2 and KMS11 cells, combined administration of Spautin-l and Palbociclib almost suppressed tumor growth within 30 days. This study thus identifies USP10 as the first deubiquitinase of CCND3 and also finds that targeting the USP10/CCND3/CDK4/6 axis may be a novel modality for the treatment of myeloma.

[p53 regulates primordial follicle activation through the mTOR signaling pathway].

This paper aimed to investigate the role and potential mechanism of p53 on primordial follicle activation. Firstly, the p53 mRNA expression in the ovary of neonatal mice at 3, 5, 7 and 9 days post-partum (dpp) and the subcellular localization of p53 were detected to confirm the expression pattern of p53. Secondly, 2 dpp and 3 dpp ovaries were cultured with p53 inhibitor Pifithrin-µ (PFT-µ, 5 µmol/L) or equal volume of dimethyl sulfoxide for 3 days. The function of p53 in primordial follicle activation was determined by hematoxylin staining and whole ovary follicle counting. The proliferation of cell was detected by immunohistochemistry. The relative mRNA levels and protein levels of the key molecules involved in the classical pathways associated with the growing follicles were examined by immunofluorescence staining, Western blot and real-time PCR, respectively. Finally, rapamycin (RAP) was used to intervene the mTOR signaling pathway, and ovaries were divided into four groups: Control, RAP (1 µmol/L), PFT-µ (5 µmol/L), PFT-µ (5 µmol/L) + RAP (1 µmol/L) groups. The number of follicles in each group was determined by hematoxylin staining and whole ovary follicle counting. The results showed that the expression of p53 mRNA was decreased with the activation of primordial follicles in physiological condition. p53 was expressed in granulosa cells and oocyte cytoplasm of the primordial follicles and growing follicles, and the expression of p53 in the primordial follicles was higher than that in the growing follicles. Inhibition of p53 promoted follicle activation and reduced the primordial follicle reserve. Inhibition of p53 promoted the proliferation of the granulosa cells and oocytes. The mRNA and protein expression levels of key molecules in the PI3K/AKT signaling pathway including AKT, PTEN, and FOXO3a were not significantly changed after PFT-µ treatment, while the expression of RPS6/p-RPS6, the downstream effectors of the mTOR signaling pathway, was upregulated. Inhibition of both p53 and mTOR blocked p53 inhibition-induced primordial follicle activation. Collectively, these findings suggest that p53 may inhibit primordial follicle activation through the mTOR signaling pathway to maintain the primordial follicle reserve.

Anemoside B4 inhibits enterovirus 71 propagation in mice through upregulating 14-3-3 expression and type I interferon responses.

Enterovirus 71 (EV71) is the major pathogens of human hand, foot, and mouth disease (HFMD). EV71 efficiently escapes innate immunity responses of the host to cause infection. At present, no effective antiviral drugs for EV71 are available. Anemoside B4 (B4) is a natural saponin isolated from the roots of Pulsatilla chinensis (Bunge) Regel. P. chinensis extracts that shows a wide variety of biological activities. In this study, we investigated the antiviral activities of B4 against EV71 both in cell culture and in suckling mice. We showed that B4 (12.5-200 µM) dose dependently increased the viability of EV71-infected RD cells with an IC50 value of 24.95 ± 0.05 µM against EV71. The antiviral activity of B4 was associated with enhanced interferon (IFN)-ß response, since knockdown of IFN-ß abolished its antiviral activity. We also confirmed that the enhanced IFN response was mediated via activation of retinoic acid-inducible gene I (RIG-I) like receptors (RLRs) pathway, and it was executed by upregulation of 14-3-3 protein, which disrupted the interaction between yes-associated protein (YAP) and interferon regulatory factor 3 (IRF3). By using amino acids in cell culture (SILAC)-based proteomics profiling, we identified the Hippo pathway as the top-ranking functional cluster in B4-treated EV71-infected cells. In vivo experiments were conducted in suckling mice (2-day-old) infected with EV71 and subsequently B4 (200 mg · kg-1 · d-1, i.p.) was administered for 16 days. We showed that B4 administration effectively suppressed EV71 replication and improved muscle inflammation and limb activity. Meanwhile, B4 administration regulated the expressions of HFMD biomarkers IL-10 and IFN-γ, attenuating complications of EV71 infection. Collectively, our results suggest that B4 could enhance the antiviral effect of IFN-ß by orchestrating Hippo and RLRs pathway, and B4 would be a potential lead compound for developing an anti-EV71 drug.

[Overview of systematic reviews of Shufeng Jiedu Capsules].

At present, there have been many clinical trials and systematic reviews/Meta-analysis proving the good clinical efficacy of Shufeng Jiedu Capsules in the treatment of respiratory diseases, while comprehensive discussion is still required. This article overviews and analyzes the systematic reviews/Meta-analysis of Shufeng Jiedu Capsules to provide evidence support for clinical practice. The systematic reviews/Meta-analysis of Shufeng Jiedu Capsules were searched from CBM, Wanfang, CNKI, VIP, PubMed, EMbase and Cochrane Library. The AMSTAR 2 scale and GRADE system were respectively employed for the evaluation of methodological quality and the grading of evidence quality. Finally, 8 systematic reviews/Meta-analysis published during 2018-2021 were included for analysis. The diseases involved include acute exacerbation of chronic obstructive pulmonary disease, community-acquired pneumonia, acute tonsillitis, acute exacerbation of chronic bronchitis and acute upper respiratory tract infection. The number of included RCTs studies ranged from 8 to 25. The results showed that Shufeng Jiedu Capsules combined with western medicine routine had better therapeutic effect than the latter alone in the treatment of the above five diseases. The reported adverse reactions caused by Shufeng Jiedu Capsules were mainly gastrointestinal discomforts such as mild nausea, diarrhoea and vomiting, with low incidence and mild symptoms, which can be relieved by drug withdrawal. The methodological quality of the included studies was extremely low, and the outcome indicators were mainly of low and very low grades. The efficacy and safety of Shufeng Jiedu Capsules in the clinical treatment of diseases still need to be verified based on more high-quality studies. The relevant clinical research and systematic review/Meta-analysis should pay more attention to methodological quality and reporting standards and strengthen the scientificity of research.

Absence of TRIM32 Leads to Reduced GABAergic Interneuron Generation and Autism-like Behaviors in Mice via Suppressing mTOR Signaling.

Mammalian target of rapamycin (mTOR) signaling plays essential roles in brain development. Hyperactive mTOR is an essential pathological mechanism in autism spectrum disorder (ASD). Here, we show that tripartite motif protein 32 (TRIM32), as a maintainer of mTOR activity through promoting the proteasomal degradation of G protein signaling protein 10 (RGS10), regulates the proliferation of medial/lateral ganglionic eminence (M/LGE) progenitors. Deficiency of TRIM32 results in an impaired generation of GABAergic interneurons and autism-like behaviors in mice, concomitant with an elevated autophagy, which can be rescued by treatment embryonically with 3BDO, an mTOR activator. Transplantation of M/LGE progenitors or treatment postnatally with clonazepam, an agonist of the GABAA receptor, rescues the hyperexcitability and the autistic behaviors of TRIM32-/- mice, indicating a causal contribution of GABAergic disinhibition. Thus, the present study suggests a novel mechanism for ASD etiology in that TRIM32 deficiency-caused hypoactive mTOR, which is linked to an elevated autophagy, leads to autism-like behaviors via impairing generation of GABAergic interneurons. TRIM32-/- mouse is a novel autism model mouse.

Biliary microbiota and mucin 4 impact the calcification of cholesterol gallstones.

BACKGROUND: Cholesterol gallstones account for over 80% of gallstones, and the pathogenesis of gallstone formation involves genetic and environmental factors. However, data on the evolution of cholesterol gallstones with various densities are limited. This study aimed to determine the roles of microbiota and mucins on the formation of calcified cholesterol gallstones in patients with cholelithiasis. METHODS: Paired gallbladder tissues and bile specimens were obtained from cholelithiasis patients who were categorized into the isodense group and calcified group according to the density of gallstones. The relative abundance of microbiota in gallbladder tissues was detected. Immunohistochemistry and enzyme-linked immunosorbent assay were performed to detect the expression levels of MUC1, MUC2, MUC3a, MUC3b, MUC4, MUC5ac and MUC5b in gallbladder tissues and bile. The correlation of microbiota abundance with MUC4 expression was evaluated by linear regression. RESULTS: A total of 23 patients with gallbladder stones were included. The density of gallstones in the isodense group was significantly lower than that of the calcified group (34.20 ± 1.50 vs. 109.40 ± 3.84 HU, P < 0.0001). Compared to the isodense group, the calcified group showed a higher abundance of gram-positive bacteria at the fundus, in the body and neck of gallbladder tissues. The concentrations of MUC1, MUC2, MUC3a, MUC3b, MUC5ac and MUC5b in the epithelial cells of gallbladder tissues showed no difference between the two groups, while the concentrations of MUC4 were significantly higher in the calcified group than that in the isodense group at the fundus (15.49 ± 0.69 vs. 10.23 ± 0.54 ng/mL, P < 0.05), in the body (14.54 ± 0.94 vs. 11.87 ± 0.85 ng/mL, P < 0.05) as well as in the neck (14.77 ± 1.04 vs. 10.85 ± 0.72 ng/mL, P < 0.05) of gallbladder tissues. Moreover, the abundance of bacteria was positively correlated with the expression of MUC4 (r = 0.569, P < 0.05) in the calcified group. CONCLUSIONS: This study showed the potential clinical relevance among biliary microbiota, mucins and calcified gallstones in patients with gallstones. Gram-positive microbiota and MUC4 may be positively associated with the calcification of cholesterol gallstones.

[A multiplex PCR method based on nuclear and cytoplasmic inheritance to identify the horse and donkey-derived components of Asini Colla Corii and the hide].

To identify the original components of Asini Colla Corii and its raw material hides provides a guarantee for authenticity of Asini Colla Corii. It is urgent for Asini Colla Corii production enterprises and market supervision departments to develop effective identification methods of Asini Colla Corii and hides derived from horses, donkeys, mules and hinnies. This study screened species-specific DNA sequences of nuclear and mitochondrial genomes as detection targets, designed horse and donkey specific primers and established multiple PCR identification methods for identifying the animal hides (including the horse, donkey, mule and hinny) and Asini Colla Corii containing horse-derived and donkey-derived components. Our method can identify the horse, donkey, mule and hinny hides and horse, donkey-derived components of Asini Colla Corii with high species specificity (no crossed amplification was observed ). The limit of detection was 0.2 ng DNA. The method developed in this study provides technical support for Asini Colla Corii production enterprises and market supervision departments.

Highly Enantioselective Construction of Strained Spiro[2,3]hexanes through a Michael Addition/Ring Expansion/Cyclization Cascade.

We herein report a general organocatalytic enantioselective strategy for the construction of highly strained spiro[2,3]hexane skeletons from methylenecyclopropanes and a broad selection of α,ß-unsaturated aldehydes. The reaction proceeds through a Michael addition followed by ring expansion of methylenecyclopropanes and nucleophilic attack of an enamine to realize the construction of spiro[2,3]hexanes. Key to the success of this approach are the utilization of an electron-deficient difluoro-substituted secondary amine catalyst and the intrinsic reactivity of methylenecyclopropanes.

Visible Light Photoredox-Catalyzed α-Alkylation of Cyclic Tertiary Arylamines.

An efficient method was successfully developed to obtain cyclic ß-amino ketones via visible-light photoredox catalysis. With this catalytic system, vinyl azides and N-Ph pyrrolidines react to form cyclic ß-amino ketones by α-amino radical addition. This method provides a simple, mild, straightforward, and novel paradigm to prepare important ß-amino ketones.

Dual Catalytic Switchable Divergent Synthesis: An Asymmetric Visible-Light Photocatalytic Approach to Fluorine-Containing γ-Keto Acid Frameworks.

Herein, we describe a novel and efficient method for constructing a series of fluorine-containing γ-keto acid derivatives through combining visible-light photoredox catalysis and chiral Lewis acid catalysis. With this dual catalytic strategy, a variety of chiral γ-keto amides containing a gem-difluoroalkyl group and a series of fluorine-containing α,ß-unsaturated-γ-keto esters were successfully constructed with high stereoselectivities, respectively. A series of experiments showed that the chemoselectivity of this process was highly dependent on the fluorine reagents besides the Lewis acid catalysts. This approach facilitates rapid access to γ-keto acid derivatives, an important class of precursors for pharmaceuticals, plasticizers, and various other additives.

Synthesis and Configurational Character Study of Novel Structural Isomers Based on Pyrene-Imidazole.

Isomers provide more possibilities for the structure of organic compounds. Molecular structures determine their corresponding properties, therefore the intrinsic relationship between structure and properties of isomers is of great research value. Isomers with a stable structure and excellent performance possess more potential for development and application. In this paper, we design and synthesize structural isomers with different molecular symmetries based on the asymmetric structure of imidazole and the symmetrical structure of pyrene. Isomers with stable molecular structures can be obtained by a simple and efficient "one-pot" reaction, involving axisymmetric configuration and centrosymmetric configuration. Using this "click-like" reaction, the structure of target molecules is controllable and adjustable. Furthermore, the effect of molecular configurations on molecular stacking of crystal is studied. The variation of the optical and thermal properties, the optimized structures, and orbital distributions of isomers depends on different molecular geometry with different symmetry, which are revealed by crystallographic analysis. This present strategy provides an efficient synthetic method for the design and synthesis of structural isomers based on pyrene-imidazole.

Transition-Metal-Free Selective C-H Benzylation of Tertiary Arylamines by a Dearomatization-Aromatization Sequence.

Due to the significance of hybrid systems in drug discovery, there is an urgent need to assemble multiple biologically active ingredients into a single molecule. Here, we report a general transition-metal-free selective C-H benzylation of tertiary arylamines in good to excellent yields with a broad substrate scope and high functional-group tolerance under mild conditions. Besides arylamines, some other benzene derivatives also readily furnished the corresponding diaryl methane derivatives with this protocol. A series of control experiments and theoretical calculations indicated that this transition-metal-free reaction is a dearomatization-aromatization process.

Dual C(sp3 )-H Bond Functionalization of N-Heterocycles through Sequential Visible-Light Photocatalyzed Dehydrogenation/[2+2] Cycloaddition Reactions.

Herein we describe a mild method for the dual C(sp3 )-H bond functionalization of saturated nitrogen-containing heterocycles through a sequential visible-light photocatalyzed dehydrogenation/[2+2] cycloaddition procedure. As a complementary approach to the well-established use of iminium ion and α-amino radical intermediates, the elusive cyclic enamine intermediates were effectively generated by photoredox catalysis under mild conditions and efficiently captured by acetylene esters to form a wide array of bicyclic amino acid derivatives, thus enabling the simultaneous functionalization of two vicinal C(sp3 )-H bonds.

PPh3 Mediated Reductive Annulation Reaction between Isatins and Electron Deficient Dienes to Construct Spirooxindole Compounds.

A PPh3 mediated reductive annulation reaction between isatins and 4,4-dicyano-2-methylenebut-3-enoates was developed. The reaction provided an alternative method for constructing five- and three-membered all-carbon spirooxindole compounds. Lithium chloride as a Lewis acid played a key role in the synthesis of spirocyclopentenyl oxindole compounds.