Computational design and engineering of self-assembling multivalent microproteins with therapeutic potential against SARS-CoV-2.

Multivalent drugs targeting homo-oligomeric viral surface proteins, such as the SARS-CoV-2 trimeric spike (S) protein, have the potential to elicit more potent and broad-spectrum therapeutic responses than monovalent drugs by synergistically engaging multiple binding sites on viral targets. However, rational design and engineering of nanoscale multivalent protein drugs are still lacking. Here, we developed a computational approach to engineer self-assembling trivalent microproteins that simultaneously bind to the three receptor binding domains (RBDs) of the S protein. This approach involves four steps: structure-guided linker design, molecular simulation evaluation of self-assembly, experimental validation of self-assembly state, and functional testing. Using this approach, we first designed trivalent constructs of the microprotein miniACE2 (MP) with different trimerization scaffolds and linkers, and found that one of the constructs (MP-5ff) showed high trimerization efficiency, good conformational homogeneity, and strong antiviral neutralizing activity. With its trimerization unit (5ff), we then engineered a trivalent nanobody (Tr67) that exhibited potent and broad neutralizing activity against the dominant Omicron variants, including XBB.1 and XBB.1.5. Cryo-EM complex structure confirmed that Tr67 stably binds to all three RBDs of the Omicron S protein in a synergistic form, locking them in the "3-RBD-up" conformation that could block human receptor (ACE2) binding and potentially facilitate immune clearance. Therefore, our approach provides an effective strategy for engineering potent protein drugs against SARS-CoV-2 and other deadly coronaviruses.

[Meta-analysis of the relationship between maternal arsenic exposure and preterm birth].

OBJECTIVE: To systematic evaluate the association between maternal arsenic exposure and preterm birth. METHODS: A literature search was conducted through Pubmed, Web of Science, Embase, China Knowledge Network(CNKI), WanFang Data, Vip Chinese Journal Service Platform(VIP) with a time frame of November 2022 from the beginning of database construction. Meta-analysis of dichotomous variables was performed using Stata MP15 software, and a random or fixed effects model was chosen for the meta-analysis based on the heterogeneity result, with the ratio of ratios(OR) as the effect indicator; subgroup analysis was used to find characteristic changes; funnel plots were used to evaluate publication bias. RESULTS: A total of 15 papers with a sample size of(n=9 892 256 279), 10 prospective cohort studies, 3 retrospective cohort studies, and 2 cross-sectional studies, were included in 6 Chinese and 9 English papers. By Meta-analysis, the combined OR of preterm birth outcome was 1.06(95%CI 1.03-1.09); the result of subgroup analysis by exposure factors and region, the combined OR(95%CI) of hair, blood, urine, drinking water, and placenta were 0.97(0.56-1.69), 1.40(1.22-1.60), 1.04(0.93-1.17), 1.14(1.04-1.24) and 0.69(0.07-6.38). The combined OR(95%CI) were 1.17(1.04-1.31), 1.10(1.05-1.14), 0.69(0.07-6.38) and 1.17(1.01-1.36) for Asia, Americas, Europe and Africa, respectively. For subgroup analysis based on study type, the combined OR(95%CI) was 1.16(1.05-1.28), 1.01(1.01-1.02) and 1.65(0.73-3.74) for prospective cohort studies, retrospective cohort studies, and cross-sectional studies, respectively. CONCLUSION: Maternal arsenic exposure may contribute to the occurrence of preterm birth, and drinking water arsenic levels may be an important indicator for assessing human arsenic exposure and risk of causing preterm birth.

Dealkenylative Ni-Catalyzed Cross-Coupling Enabled by Tetrazine and Photoexcitation.

A new and general method to functionalize the C(sp3)-C(sp2) bond of alkyl and alkene linkages has been developed, leading to the dealkenylative generation of carbon-centered radicals that can be intercepted to undergo Ni-catalyzed C(sp3)-C(sp2) cross-coupling. This one-pot protocol leverages the easily procured alkene feedstocks for organic synthesis with excellent functional group compatibility without the need for a photoredox catalyst.

Oyster-Derived Zinc-Binding Peptide Modified by Plastein Reaction via Zinc Chelation Promotes the Intestinal Absorption of Zinc.

Zinc-binding peptides from oyster (Crassostrea gigas) have potential effects on zinc supplementation. The aim of this study was to prepare efficient zinc-binding peptides from oyster-modified hydrolysates by adding exogenous glutamate according to the plastein reaction and to further explore the zinc absorption mechanism of the peptide-zinc complex (MZ). The optimum conditions for the plastein reaction were as follows: pH 5.0, 40 °C, substrate concentration of 40%, pepsin dosage of 500 U/g, reaction time of 3 h and l-[1-13C]glutamate concentration of 10 mg/mL. The results of 13C isotope labelling suggested that the addition of l-[1-13C]glutamate contributed to the increase in the zinc-binding capacity of the peptide. The hydrophobic interaction was the main mechanism of action of the plastein reaction. Ultraviolet spectra and scanning electronic microscopy (SEM) revealed that the zinc-binding peptide could bind with zinc and form MZ. Furthermore, MZ could significantly enhance zinc bioavailability in the presence of phytic acid, compared to the commonly used ZnSO4. Additionally, MZ significantly promoted the intestinal absorption of zinc mainly through two pathways, the zinc ion channel and the small peptide transport pathway. Our work attempted to increase the understanding of the zinc absorption mechanism of MZ and to support the potential application of MZ as a supplementary medicine.

TTYH3 promotes the malignant progression of oral squamous cell carcinoma SCC-9 cells by regulating tumor-associated macrophage polarization.

OBJECTIVE: This study was designed to investigate the biological role and the reaction mechanism of Tweety family member 3 (TTYH3) in oral squamous cell carcinoma (OSCC). DESIGN: The mRNA and protein expressions of TTYH3 were assessed with RT-qPCR and western blot. After silencing TTYH3 expression, the proliferation of OSCC cells were detected using cell counting kit-8 (CCK-8) assay, 5-ethynyl-2'-deoxyuridine (EdU) staining and colony formation assay. Cell migration and invasion were detected using wound healing and transwell. Gelatin zymography protease assay was used to detect matrix metalloproteinase-2 (MMP2) and matrix metalloproteinase-2 (MMP9) activity and western blot was used to detect the expressions of proteins associated with proliferation and epithelial-mesenchymal transition (EMT). The mRNA expression of TTYH3 in THP-1-derived macrophage was detected using real-time reverse transcriptase-polymerase chain reaction (RT-qPCR). The number of CD86-positive cells and CD206-positive cells was detected using immunofluorescence assay. RT-qPCR was used to detect the expressions of M2 markers arginase 1 (ARG1), chitinase-like 3 (YM1) and mannose receptor C-type 1 (MRC1). RESULTS: In this study, it was found that TTYH3 expression was upregulated in OSCC cell lines and TTYH3 knockdown could inhibit the proliferation, migration, invasion and EMT process in OSCC via suppressing M2 polarization of tumor-associated macrophages. CONCLUSIONS: Collectively, TTYH3 facilitated the progression of OSCC through the regulation of tumor-associated macrophages polarization.

Methods for Assessing Circadian Rhythms and Cell Cycle in Intestinal Enteroids.

Endogenous circadian clocks play a key role in regulating a vast array of biological processes from cell cycle to metabolism, and disruption of circadian rhythms exacerbates a range of human ailments including cardiovascular, metabolic, and gastrointestinal diseases. Determining the state of a patient's circadian rhythms and clock-controlled signaling pathways has important implications for precision and personalized medicine, from improving the diagnosis of circadian-related disorders to optimizing the timing of drug delivery. Patient-derived 3-dimensional enteroids or in vitro "mini gut" is an attractive model uncovering human- and patient-specific circadian target genes that may be critical for personalized medicine. Here, we introduce several procedures to assess circadian rhythms and cell cycle dynamics in enteroids through time course sample collection methods and assay techniques including immunofluorescence, live cell confocal microscopy, and bioluminescence. These methods can be applied to evaluate the state of circadian rhythms and circadian clock-gated cell division cycles using mouse and human intestinal enteroids.

Synthesis of 17-Deacetoxyl Chromodorolide B Based on a Gold-Catalyzed Alkoxycyclization Reaction.

A novel strategy to construct the highly oxidized 3-oxabicyclo[3.3.0]octane skeleton was developed via a gold-catalyzed cascade cyclization with 2,7-dioxabicyclo[3.2.0]hept-3-ene as the substrate. We utilized this methodology as the key reaction to synthesize 17-deacetoxyl chromodorolide B.

Magnetically Separable Fe3O 4/AgBr Hybrid Materials: Highly Efficient Photocatalytic Activity and Good Stability.

Magnetically separable Fe3O4/AgBr hybrid materials with highly efficient photocatalytic activity were prepared by the precipitation method. All of them exhibited much higher photocatalytic activity than the pure AgBr in photodegradation of methyl orange (MO) under visible light irradiation. When the loading amount of Fe3O4 was 0.5 %, the hybrid materials displayed the highest photocatalytic activity, and the degradation yield of MO reached 85 % within 12 min. Silver halide often suffers serious photo-corrosion, while the stability of the Fe3O4/AgBr hybrid materials improved apparently than the pure AgBr. Furthermore, depositing Fe3O4 onto the surface of AgBr could facilitate the electron transfer and thereby leading to the elevated photocatalytic activity. The morphology, phase structure, and optical properties of the composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-visible diffuse reflectance spectra (UV-vis DRS), and photoluminescence (PL) techniques.