Design, synthesis and bioactivity evaluation of novel monomethyl auristatin F analogues.

Monomethyl auristatin F (MMAF), a synthetic analogue of the natural compound dolastatin 10, has garnered significant attention in cancer research due to its high potency in vitro. While previous studies have focused on modifying the N-terminal extension of the amino group and the C-terminal modification of the carboxyl group, there has been limited exploration into modifying the P1 and P5 side chains. In this study, we substituted the valine residue at the P1 position with various natural or unnatural amino acids and introduced triazole functional groups at the P5 side chain. Compounds 11k and 18d exhibited excellent inhibition on tubulin. Additionally, compound 18d demonstrated enhanced cytotoxicity against HCT116 cells compared to the parent compound MMAF, suggesting its potential as a cytotoxic payload for further antibody-drug conjugates (ADCs) development.

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines.

Herein, we report a visible-light-mediated palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines, affording unsaturated γ- and ε-amino acid derivatives with diverse structures. In this methodology, the diazo compound readily transforms into a hybrid α-ester alkylpalladium radical with the release of dinitrogen. The radical intermediate selectively adds to the double bond of a 1,3-diene or allene, followed by the allylpalladium radical-polar crossover path and selective allylic substitution with the amine substrate, thereby leading to a single unsaturated γ- or ε-amino acid derivative. This approach proceeds under mild and simple reaction conditions and shows high functional group tolerance, especially in the incorporation of various bioactive molecules. The studies on scale-up reactions and diverse derivatizations highlight the practical utility of this multicomponent reaction protocol.

Identification of gut microbiome and transcriptome changes in ulcerative colitis and pouchitis.

BACKGROUND: Pouchitis is the common postoperative complication of ulcerative colitis (UC) and is also considered as inflammatory bowel disease. The aim was to investigate the microbiological and transcriptional differences between the two illnesses. METHODS: Eighty-five participants were enrolled (37 UC, 15 healthy UC pouches, 15 pouchitis and 18 healthy volunteers) and stool samples were collected. Microbial populations were analyzed by pyrosequencing of 16S ribosomal DNA. Furthermore, transcriptome data of 119 UC and 28 pouch patients were obtained from two data sets for bioinformatics analysis. RESULTS: The results of gut microbiota community analysis showed that with aggravation of UC, intestinal microorganisms were characterized by a gradual decreased in diversity and numbers of butyrate-producing bacteria and Bacteroides. Besides, in addition to the decrease of probiotics, the proliferation of Escherichia-Shigella and Ruminococcus gnavus was observed in pouchitis which is related to multiple infection pathways. The function enrichment of differential expression genes and hub genes, as well as the immunological condition was shown to be distinct using transcriptome bioinformatics analysis between UC and pouchitis. A stronger immune response occurs in UC and may be associated with high expression of tumor necrosis factor and interleukin, while multiple hub genes such as CDK1 in pouchitis are associated with cell cycle regulation. CONCLUSIONS: The characteristics of gut microbiota disturbance and transcriptome alteration in UC and pouchitis are different. Our findings suggested that pouchitis may have a unique pathogenesis which was separated from UC.

Genome-Wide Association Study of Kernel Black Point Resistance in Chinese Wheat Landraces.

Black point (BP) disease of wheat has become a noticeable problem in China. The symptoms are spots that are brown to black in color around the wheat kernel embryo or in the endosperm, resulting in a significant reduction of wheat grain quality. Here, we evaluated 272 Chinese wheat landraces for BP reaction and performed a genome-wide association study to identify BP resistance quantitative trait loci (QTLs) in five field environments without artificial inoculation. The BP incidence data showed continuous distributions and had low to moderate correlations between environments (r = 0.094 to 0.314). Among the 272 landraces, 11 had 0.1 to 4.9%, 144 had 5 to 14.9%, 100 had 15 to 29.9%, and 17 had >30% incidence. We found three resistant accessions: WH094 (3.33%), AS661463 (2.67%), and AS661231 (2.67%), which can be used in breeding programs to enhance BP resistance. We identified 11 QTLs, which explained 8.22 to 10.99% phenotypic BP variation, and mapped them to eight wheat chromosomes. Three of the QTLs were novel. The molecular markers for the BP resistance could facilitate molecular breeding for developing BP-resistant cultivars.

LINC00467 promotes cell proliferation and stemness in lung adenocarcinoma by sponging miR-4779 and miR-7978.

Lung adenocarcinoma (LAD), as one of the most common types of lung tumors, is lethal and malignant. Long noncoding RNAs (lncRNAs) play important roles in various cancers according to many previous studies. LINC00467 was proposed to be a tumor promoter. Despite the validated promotive effect of LINC00467 on neuroblastoma progression, its regulatory mechanism in LAD remains unclear. In this study, LINC00467 expressed higher in LAD tissues and cell lines, and increased LINC00467 indicated a poor prognosis. Knockdown of LINC00467 inhibited cell proliferation, the expressions of tumor stem cell-related genes, and cell spheroid formation ability, while it promoted cell apoptosis. miR-4779 and miR-7978 were reported to play antitumor roles in several cancers before. LINC00467 could combine with miR-4779 and miR-7978, and negatively regulated miR-4779 and miR-7978. miR-4779 and miR-7978 inhibitor could partly rescue the LINC00467 knockdown-induced influence on cell proliferation, apoptosis, and stemness. In a word, this study innovatively investigated the mechanism of LINC00467 in LAD and verified LINC00467 exerted its carcinogenesis function by sponging miR-4779 and miR-7978, which may become a catalyst for generating new therapeutic targets for LAD treatment.

Design, Synthesis, and Biological Evaluation of 8-Mercapto-3,7-Dihydro-1H-Purine-2,6-Diones as Potent Inhibitors of SIRT1, SIRT2, SIRT3, and SIRT5.

Sirtuins (SIRT1-7) are a family of NAD+-dependent deacetylases. They regulate many physiological processes and play important roles in inflammation, diabetes, cancers, and neurodegeneration diseases. Sirtuin inhibitors have potential applications in the treatment of neurodegenerative diseases and various cancers. Herein, we identified new sirtuin inhibitors based on the scaffold of 8-mercapto-3,7-dihydro-1H-purine-2,6-dione. To elucidate the inhibitory mechanism, the binding modes of the inhibitors in SIRT3 were established by molecular docking, showing that the inhibitors occupy the acetyl lysine binding site and interact with SIRT3, mainly through hydrophobic interactions. The interactions were validated by site-directed mutagenesis of SIRT3 and structure-activity relationship analysis of the inhibitors. Consistently, enzyme kinetic assays and microscale thermophoresis showed that these compounds are competitive inhibitors to the acetyl substrate, and mix-type inhibitors to NAD+. Furthermore, we demonstrated that the compounds are potent SIRT1/2/3/5 pan-inhibitors. This study provides novel hits for developing more potent sirtuin inhibitors.

Cp*Rh(III)-Catalyzed C-H Bond Difluorovinylation of Indoles with α,α-Difluorovinyl Tosylate.

Unprecedented Rh(III)-catalyzed C-H bond difluorovinylation of indoles has been successfully developed, and this method provided an example of direct difluorovinylation reaction through C-H bond activation which was rarely reported. In this context, N-ethoxycarbamoyl served as the directing group and 2,2-difluorovinyl tosylates were used for the construction of difluorovinyl-substituted indoles. This method provided a practical strategy for difluorovinylation of indoles with moderate to good yields and is characterized by the broad synthetic utility, mild conditions, and high efficiency.

Development of sandwich ELISAs that can distinguish different types of coxsackievirus A16 viral particles.

Coxsackievirus A16 (CA16) is one of the major causative agents of hand, foot, and mouth disease (HFMD). No CA16 vaccine candidates have progressed to clinical trials so far. Immunogenicity studies indicated that different CA16 particles have much influence on the efficacy of a candidate vaccine. However, there are still no relevant reports on the methods of detecting different CA16 particles. In this study, we screened several monoclonal antibodies (mAbs) specific for different CA16 particles, and several sandwich enzyme-linked immunoassays (ELISAs) were developed to measure the different types of CA16 viral particles. The mAbs that could only bind denatured or empty capsids could not neutralize CA16. In contrast, the mAbs that could bind mature full particles or all types of particles showed obvious neutralizing activity. The thermal stability of different CA16 particles was evaluated using these sandwich ELISAs. The mature full particles were found to be more thermolabile than the other types of particles and could be stabilized by high concentrations of cations. These methods can be used to assist in the potency control of CA16 vaccines and will promote the development of a CA16 vaccine.

Fast 2D DOA Estimation Algorithm by an Array Manifold Matching Method with Parallel Linear Arrays.

In this paper, the problem of two-dimensional (2D) direction-of-arrival (DOA) estimation with parallel linear arrays is addressed. Two array manifold matching (AMM) approaches, in this work, are developed for the incoherent and coherent signals, respectively. The proposed AMM methods estimate the azimuth angle only with the assumption that the elevation angles are known or estimated. The proposed methods are time efficient since they do not require eigenvalue decomposition (EVD) or peak searching. In addition, the complexity analysis shows the proposed AMM approaches have lower computational complexity than many current state-of-the-art algorithms. The estimated azimuth angles produced by the AMM approaches are automatically paired with the elevation angles. More importantly, for estimating the azimuth angles of coherent signals, the aperture loss issue is avoided since a decorrelation procedure is not required for the proposed AMM method. Numerical studies demonstrate the effectiveness of the proposed approaches.

Effects of natural orifice transluminal endoscopic radical resection of the colon and targeted therapy on immune response and blood CA199 and CA242 levels in colorectal cancer.

To examine the effect of natural orifice transluminal endoscopic radical resection combined with targeted therapy on the immune system and serum levels of CA199 and CA242 in individuals with colorectal cancer. We enrolled 90 patients admitted to our hospital with a diagnosis of colorectal cancer between February 2020 and May 2022 and divided them into 2 groups according to the treatment methods: observation group (n = 45) and control group (n = 45). Patients in the control group underwent conventional laparoscopic radical resection of the colon followed by targeted therapy, whereas those in the observation group underwent natural orifice transluminal endoscopic radical resection of the colon and targeted therapy. Serum CA199 and CA242 levels, incidence of adverse events, clinical efficacy, perioperative indicators, and immune function indicators were compared between the 2 groups. The objective response rate (ORR) and disease control rate (DCR) were significantly higher in the observation group than in the control group (60.00% vs 35.6%, P = .020, and 91.1% vs 64.44%, P = .002, respectively). Compared with the control group, the observation group was associated with less blood loss (P = .003), shorter operation time (P = .011), shorter first exhaust time (P = .042), shorter borborygmus recovery time (P = .042), and shorter length of hospital stay (P = .020). After treatment, the CD3 + (P = .020), CD4 + (P = .008), and CD4+/CD8 + (P = .035) counts were lower, whereas the IgG (P = .014), IgM (P = .019), and IgA (P = .038) counts were higher in the observation group than in the control group. CA199 (P = .009) and CA242 (P = .001) levels were lower in the observation group than in the control group. The groups did not differ significantly in the incidence of adverse events (P = .842). The combination of natural orifice transluminal endoscopic radical resection for colorectal cancer and targeted therapy can shorten hospital stay, improve immune function, lower serum levels of CA199 and CA242, and exhibit good clinical efficacy.

New evidence of the Hoyle-like structure in 16O.

An experiment of 12C(16O,16O → 4α)12C was performed at a beam energy of 96 MeV. A large number of 4-α events were recorded in coincidence and with full particle identification (PID). This was made possible by employing a series of silicon-strip-based telescopes that provided excellent position and energy resolutions. Four narrow resonances just above the 15.1 MeV state were firmly identified in the α + 12C(7.65 MeV; Hoyle state) decay channel. Combined with the theoretical predictions, these resonant states provide new evidence for the predicted possible Hoyle-like structure in 16O above the 4-α separation threshold. Some very high-lying 4-α resonant states have also been observed and need to be further investigated.

Synthesis and evaluation of new pirfenidone derivatives as anti-fibrosis agents.

Two series of new pirfenidone derivatives, in which phenyl groups or benzyl groups are attached to the nitrogen atom of the pyridin-2(1H)-one moiety were synthesized and evaluated as anti-fibrosis agents. Among them, compound 5d, with a (S)-2-(dimethylamino) propanamido group in the R2 position (series 1) exhibited 10 times the anti-fibrosis activity (IC50: 0.245 mM) of pirfenidone (IC50: 2.75 mM). Compound 9d (series 2) gave an IC50 of 0.035 mM against the human fibroblast cell line HFL1. The mechanism of the optimal compound inhibiting fibrosis was also studied.

The expression of PTHLH in human gastric mucosa enterochromaffin-like cells.

BACKGROUND: Gastrectomy may disturb the body's mineral homeostasis, with osteopenia and osteoporosis being among the late outcomes. Parathyroid hormone-like hormone (PTHLH) was detected in rat gastric enterochromaffin-like (ECL) cells in 2005, and some researchers suggested that it was the hypothetical hormone gastrocalcin that is believed to lead to osteoporosis. AIMS: Our objective was to learn whether PTHLH is expressed in human gastric ECL cells and to form a basic understanding about the relationship between PTHLH and gastrin. METHODS: We collected normal human gastric mucosa specimens and serum samples from 28 patients. RESULTS: RT-PCR and immunohistochemical analysis demonstrated weak expression of PTHLH in ECL cells at the RNA and protein levels. A low level of PTHLH expression was also found in the serum. Serum gastrin did have a significant positive correlation with the relative ratio of PTHLH mRNA to ß-actin levels in gastric mucosa (rs=0.569, p=0.002). CONCLUSIONS: This indicates that PTHLH has a low signal expression in human gastric ECL cells and that serum gastrin levels correlate with PTHLH RNA levels in gastric mucosa. Further work is needed to evaluate the functional role of PTHLH in ECL cells and to determine whether PTHLH is gastrocalcin.

Discovery of 5-Benzylidene-2-phenyl-1,3-dioxane-4,6-diones as Highly Potent and Selective SIRT1 Inhibitors.

SIRT1, a member of the sirtuin family, catalyzes the deacetylation of proteins with the transformation of NAD+ into nicotinamide and 2'-O-acetyl-ADP-ribose. Selective SIRT1/2 inhibitors have potential application in the chemotherapy of colorectal carcinoma, prostate cancer, and myelogenous leukemia. Here we identified novel SIRT1 inhibitors with the scaffold of 5-benzylidene-2-phenyl-1,3-dioxane-4,6-dione. The most potent inhibitor 12n displayed an IC50 of 460 nM and a selectivity for SIRT1 over SIRT2, SIRT3, and SIRT5 of 113.5-, 254.3-, and 10.83-fold, respectively. It did not affect the activity of SIRT6. To elucidate the inhibitory mechanism, we determined the inhibition type of the inhibitor by enzyme kinetic analysis, showing that the inhibitor was competitive to the acetyl peptide and noncompetitive to NAD+. Further, the interaction of the inhibitor in SIRT1 was studied by using molecular docking, which was validated by the structure-activity relationship analysis of the inhibitors and the site-directed mutagenesis of SIRT1. Consistent with the in vitro assays, the inhibitors increased the acetylation level of p53 in a concentration-dependent manner in cells.

Cryo-EM structures reveal the molecular basis of receptor-initiated coxsackievirus uncoating.

Enterovirus uncoating receptors bind at the surface depression ("canyon") that encircles each capsid vertex causing the release of a host-derived lipid called "pocket factor" that is buried in a hydrophobic pocket formed by the major viral capsid protein, VP1. Coxsackievirus and adenovirus receptor (CAR) is a universal uncoating receptor of group B coxsackieviruses (CVB). Here, we present five high-resolution cryoEM structures of CVB representing different stages of virus infection. Structural comparisons show that the CAR penetrates deeper into the canyon than other uncoating receptors, leading to a cascade of events: collapse of the VP1 hydrophobic pocket, high-efficiency release of the pocket factor and viral uncoating and genome release under neutral pH, as compared with low pH. Furthermore, we identified a potent therapeutic antibody that can neutralize viral infection by interfering with virion-CAR interactions, destabilizing the capsid and inducing virion disruption. Together, these results define the structural basis of CVB cell entry and antibody neutralization.

Identification of Antibodies with Non-overlapping Neutralization Sites that Target Coxsackievirus A16.

Hand, foot, and mouth disease is a common childhood illness primarily caused by coxsackievirus A16 (CVA16), for which there are no current vaccines or treatments. We identify three CVA16-specific neutralizing monoclonal antibodies (nAbs) with therapeutic potential: 18A7, 14B10, and NA9D7. We present atomic structures of these nAbs bound to all three viral particle forms-the mature virion, A-particle, and empty particle-and show that each Fab can simultaneously occupy the mature virion. Additionally, 14B10 or NA9D7 provide 100% protection against lethal CVA16 infection in a neonatal mouse model. 18A7 binds to a non-conserved epitope present in all three particles, whereas 14B10 and NA9D7 recognize broad protective epitopes but only bind the mature virion. NA9D7 targets an immunodominant site, which may overlap the receptor-binding site. These findings indicate that CVA16 vaccines should be based on mature virions and that these antibodies could be used to discriminate optimal virion-based immunogens.

Meta-Analysis: The Influence of Preoperative Infliximab Use on Postoperative Complications of Crohn's Disease.

Background: Infliximab (IFX) is a breakthrough treatment for refractory Crohn's disease (CD) whose effect on postoperative complications of CD remains controversial. The purpose of this study was to conduct a meta-analysis examining the effect of IFX on postoperative complications of CD. Methods: We searched "PubMed," "EMBASE," and "Cochrane Library" databases from inception of each database until March 2018. All eligible articles were screened according to the inclusion criteria. The cumulative overall, major, minor, infectious, noninfectious, surgical, and medical complications, as well as reoperation, readmission, and mortality of CD patients who received IFX and underwent ileocolonic resection were extracted and analyzed using Review Manager 5.3. The random effects model was used to calculate the odds ratio (OR) and 95% confidence interval (CI). Results: A total of 18 nonrandomized controlled trial studies, with 1407 patients who received IFX and 4589 patients who did not were identified. The incidence of complications was 9.38%-60.56% in the IFX group and 12.73%-53.85% in the control group. Overall, major, minor, infectious, noninfectious, surgical, and medical complications could be assessed in 16, 12, 11, 14, 12, 12, and 11 studies, respectively. There were no statistically significant differences between the 2 groups for any complication (P > 0.05, all comparisons). Reoperation (P = 0.70), readmission (P = 0.22) and mortality (P = 0.86) showed no significant difference between the 2 groups. Subgroup analysis showed that complications were not significantly different among the countries represented in the studies. Conclusions: Based on this analysis, there does not appear to be an association between preoperative IFX treatment and postoperative complications of CD; IFX appears relatively safe for preoperative use in the treatment of CD. 10.1093/ibd/izy246_video1izy246.video15813237394001.

Atomic structures of enterovirus D68 in complex with two monoclonal antibodies define distinct mechanisms of viral neutralization.

Enterovirus D68 (EV-D68) undergoes structural transformation between mature, cell-entry intermediate (A-particle) and empty forms throughout its life cycle. Structural information for the various forms and antibody-bound capsids will facilitate the development of effective vaccines and therapeutics against EV-D68 infection, which causes childhood respiratory and paralytic diseases worldwide. Here, we report the structures of three EV-D68 capsid states representing the virus at major phases. We further describe two original monoclonal antibodies (15C5 and 11G1) with distinct structurally defined mechanisms for virus neutralization. 15C5 and 11G1 engage the capsid loci at icosahedral three-fold and five-fold axes, respectively. To block viral attachment, 15C5 binds three forms of capsids, and triggers mature virions to transform into A-particles, mimicking engagement by the functional receptor ICAM-5, whereas 11G1 exclusively recognizes the A-particle. Our data provide a structural and molecular explanation for the transition of picornavirus capsid conformations and demonstrate distinct mechanisms for antibody-mediated neutralization.

A neonatal mouse model of coxsackievirus A10 infection for anti-viral evaluation.

Epidemiological data indicate that coxsackievirus A10 (CVA10) has become one of the main causative agents of hand, foot and mouth disease (HFMD) and in recent years has often been found to co-circulate with other enteroviruses, which poses a challenge for the prevention and control of HFMD. Although most CVA10-associated HFMD cases present mild symptoms, severe manifestations and even death can also occur. However, the study of the pathogenesis and the development of drugs and vaccines for CVA10 infection are still far from complete. In this study, we established a neonatal mouse model for anti-viral evaluation and characterized the pathology of CVA10 infection. To develop the mouse model, both inbred and outbred mouse strains were used to compare their sensitivity to CVA10 infection; then, one-day-old BALB/c mice were selected and inoculated intraperitoneally with a CVA10 clinical strain, CVA10-FJ-01. Clinical symptoms, such as wasting, hind-limb paralysis and even death were observed in the CVA10-infected mice. Moreover, pathological examination and immunohistochemistry staining showed that severe myonecrosis with inflammatory infiltration was observed in CVA10-infected mice, indicating that CVA10 exhibited strong tropism to muscle tissue. Using real-time PCR, we also found that the viral load in the blood and muscle was higher than that in other organs/tissues at different time points post-infection, suggesting that CVA10 had a strong tropism to mice muscle and that viremic spread may also contribute to the death of the CVA10-infected mice. Additionally, to evaluate the neonatal mouse model of CVA10 infection, female mice were immunized with formalin-inactivated CVA10 and then allowed to mate after the third immunization. The results showed that maternal antibodies could protect mice against CVA10 infection. In summary, the results demonstrated that the neonatal mice model was a useful tool for evaluating the protective effects of CVA10 vaccines and anti-viral reagents.

Atomic structures of Coxsackievirus A6 and its complex with a neutralizing antibody.

Coxsackievirus A6 (CVA6) has recently emerged as a major cause of hand, foot and mouth disease in children worldwide but no vaccine is available against CVA6 infections. Here, we demonstrate the isolation of two forms of stable CVA6 particles-procapsid and A-particle-with excellent biochemical stability and natural antigenicity to serve as vaccine candidates. Despite the presence (in A-particle) or absence (in procapsid) of capsid-RNA interactions, the two CVA6 particles have essentially identical atomic capsid structures resembling the uncoating intermediates of other enteroviruses. Our near-atomic resolution structure of CVA6 A-particle complexed with a neutralizing antibody maps an immune-dominant neutralizing epitope to the surface loops of VP1. The structure-guided cell-based inhibition studies further demonstrate that these loops could serve as excellent targets for designing anti-CVA6 vaccines.Coxsackievirus A6 (CVA6) causes hand, foot and mouth disease in children. Here the authors present the CVA6 procapsid and A-particle cryo-EM structures and identify an immune-dominant neutralizing epitope, which can be exploited for vaccine development.