Enhancing protein dynamics analysis with hydrophilic polyethylene glycol cross-linkers.

Cross-linkers play a critical role in capturing protein dynamics in chemical cross-linking mass spectrometry techniques. Various types of cross-linkers with different backbone features are widely used in the study of proteins. However, it is still not clear how the cross-linkers' backbone affect their own structure and their interactions with proteins. In this study, we systematically characterized and compared methylene backbone and polyethylene glycol (PEG) backbone cross-linkers in terms of capturing protein structure and dynamics. The results indicate the cross-linker with PEG backbone have a better ability to capture the inter-domain dynamics of calmodulin, adenylate kinase, maltodextrin binding protein and dual-specificity protein phosphatase. We further conducted quantum chemical calculations and all-atom molecular dynamics simulations to analyze thermodynamic and kinetic properties of PEG backbone and methylene backbone cross-linkers. Solution nuclear magnetic resonance was employed to validate the interaction interface between proteins and cross-linkers. Our findings suggest that the polarity distribution of PEG backbone enhances the accessibility of the cross-linker to the protein surface, facilitating the capture of sites located in dynamic regions. By comprehensively benchmarking with disuccinimidyl suberate (DSS)/bis-sulfosuccinimidyl-suberate(BS3), bis-succinimidyl-(PEG)2 revealed superior advantages in protein dynamic conformation analysis in vitro and in vivo, enabling the capture of a greater number of cross-linking sites and better modeling of protein dynamics. Furthermore, our study provides valuable guidance for the development and application of PEG backbone cross-linkers.

MicroRNA-431-5p inhibits angiogenesis, lymphangiogenesis, and lymph node metastasis by affecting TGF-ß1/SMAD2/3 signaling via ZEB1 in gastric cancer.

Accumulating evidence suggests that lymphangiogenesis plays a crucial role in lymphatic metastasis, leading to tumor immune tolerance. However, the specific mechanism remains unclear. In this study, miR-431-5p was markedly downregulated in both gastric cancer (GC) tissues and plasma exosomes, and its expression were correlated negatively with LN metastasis and poor prognosis. Mechanistically, miR-431-5p weakens the TGF-ß1/SMAD2/3 signaling pathway by targeting ZEB1, thereby suppressing the secretion of VEGF-A and ANG2, which in turn hinders angiogenesis, lymphangiogenesis, and lymph node (LN) metastasis in GC. Experiments using a popliteal LN metastasis model in BALB/c nude mice demonstrated that miR-431-5p significantly reduced popliteal LN metastasis. Additionally, miR-431-5p enhances the efficacy of anti-PD1 treatment, particularly when combined with galunisertib, anti-PD1 treatment showing a synergistic effect in inhibiting GC progression in C57BL/6 mice. Collectively, these findings suggest that miR-431-5p may modulate the TGF-ß1/SMAD2/3 pathways by targeting ZEB1 to impede GC progression, angiogenesis, and lymphangiogenesis, making it a promising therapeutic target for GC management.

Myosteatosis predicts postoperative complications and long-term survival in robotic gastrectomy for gastric cancer: A propensity score analysis.

BACKGROUND: Robotic gastrectomy is increasingly utilized for gastric cancer, but high morbidity remains a concern. Myosteatosis or low skeletal muscle density reflecting fatty infiltration, associates with complications after other cancer surgeries but has not been evaluated for robotic gastrectomy. METHODS: This retrospective study analysed 381 patients undergoing robotic gastrectomy for gastric cancer from September 2019 to October 2022. Myosteatosis was quantified on preoperative computed tomography (CT) images at lumbar 3 (L3). Propensity score matching addressed potential confounding between myosteatosis and non-myosteatosis groups. Outcomes were postoperative complications, 30 days mortality, 30 days readmissions and survival. RESULTS: Myosteatosis was present in 33.6% of patients. Myosteatosis associated with increased overall (47.7% vs. 26.5%, p < 0.001) and severe complications (12.4% vs. 4.9%, p < 0.001). After matching, myosteatosis remained associated with increased overall complications, major complications, intensive care unit (ICU) transfer and readmission (all p < 0.05). Myosteatosis independently predicted overall [odds ratio (OR) = 2.86, 95% confidence interval (CI): 1.57-5.20, p = 0.001] and severe complications (OR = 4.81, 95% CI: 1.51-15.27, p = 0.008). Myosteatosis also associated with reduced overall (85.0% vs. 93.2%, p = 0.015) and disease-free survival (80.3% vs. 88.4%, p=0.029). On multivariate analysis, myosteatosis independently predicted poorer survival [hazard ratio (HR) = 2.83, 95% CI: 1.32-6.08, p=0.012] and disease-free survival (HR = 1.83, 95% CI: 1.01-3.30, p=0.032). CONCLUSION: Preoperative CT-defined myosteatosis independently predicts increased postoperative complications and reduced long-term survival after robotic gastrectomy for gastric cancer. Assessing myosteatosis on staging CT could optimize preoperative risk stratification.

Long non-coding RNA LINC00930 targeting miR-6792-3p/ZBTB16 regulates the proliferation and EMT of pancreatic cancer.

Emerging evidence suggests the dysregulation of long non-coding RNAs (lncRNAs) involved in pancreatic cancer (PC). However, the function of LINC00930 in PC has not been elaborated. In this study, we found that LINC00930 was significantly down-regulated in PC cell lines and tissues, and associated with tumor size, lymphatic metastasis, TNM stage and poor prognosis. According to the bioinformatics database, the downregulation of LINC00930 was a common event in PC associated with prognosis and EMT. Overexpression of LINC00930 inhibited the aggressive cancer phenotypes including proliferation, metastasis and epithelial-mesenchymal transition (EMT) of PC in vitro and in vivo. Bioinformatics and dual-luciferase reporter assay indicated that miR-6792-3p could directly bind to LINC00930. Additionally, the Zinc finger and BTB domain containing 16 (ZBTB16) was significantly declined in PC, which was predicted to be the downstream gene of miR-6792-3p. MiR-6792-3p mimic rescued the decreased proliferation, metastasis and EMT caused by ZBTB16 in PC cells. The LINC00930/miR-6792-3p/ZBTB16 axis was associated with the malignant progression and process of PC. The relative expression of LINC00930 was negatively correlated with the expression of miR-6792-3p and was closely linked with ZBTB16 levels in PC. LINC00930 might serve as a potential prognostic biomarker and therapeutic target for PC.

Combined systemic inflammatory immune index and prognostic nutrition index as chemosensitivity and prognostic markers for locally advanced gastric cancer receiving neoadjuvant chemotherapy: a retrospective study.

BACKGROUND: The prognosis nutritional index (PNI) and the systemic inflammatory immunological index (SII) are characteristic indicators of the nutritional state and the systemic inflammatory response, respectively. However, there is an unknown combined effect of these indicators in the clinic. Therefore, the practicality of using the SII-PNI score to predict prognosis and tumor response of locally advanced gastric cancer (LAGC) following chemotherapy was the main focus of this investigation. METHODS: We retrospectively analyzed 181 patients with LAGC who underwent curative resection after neoadjuvant chemotherapy in a prospective study (NCT01516944). We divided these patients into tumour regression grade(TRG) 3 and non-TRG3 groups based on tumor response (AJCC/CAP guidelines). The SII and PNI were assessed and confirmed the cut-off values before treatment. The SII-PNI values varied from 0 to 2, with 2 being the high SII (≥ 471.5) as well as low PNI (≤ 48.6), a high SII or low PNI is represented by a 1 and neither is represented by a 0, respectively. RESULTS: 51 and 130 samples had TRG3 and non-TRG3 tumor responses respectively. Patients with TRG3 had substantially higher SII-PNI scores than those without TRG3 (p < 0.0001). Patients with greater SII-PNI scores had a poorer prognosis (p < 0.0001). The SII-PNI score was found to be an independent predictor of both overall survival (HR = 4.982, 95%CI: 1.890-10.234, p = 0.001) and disease-free survival (HR = 4.763, 95%CI: 1.994-13.903, p = 0.001) in a multivariate analysis. CONCLUSION: The clinical potential and accuracy of low-cost stratification based on SII-PNI score in forecasting tumor response and prognosis in LAGC is satisfactory.

Safety evaluation and effects of dietary phlorotannins on the growth, health, and intestinal microbiota of Litopenaeus vannamei.

Phlorotannins are phenolic compounds with diverse biological activities, yet their efficacy in aquatic animals currently remains unclear. This investigation scrutinized the influence of phlorotannins on the growth, immunity, antioxidant capacity, and intestinal microbiota in Litopenaeus vannamei, concurrently evaluating the potential adverse effects of phlorotannins on L. vannamei. A base diet without phlorotannins supplementation was used as a control, and 4 groups of diets with different concentrations (0, 0.5, 1.0, 2.0 g kg-1) of phlorotannins were formulated and fed to juvenile shrimp (0.25 ± 0.01 g) for 60 days followed by a 24-h challenge with Vibrio parahaemolyticus with triplicate in each group. Compared with the control, dietary 2.0 g kg-1 phlorotannins significantly improved the growth of the shrimp. The activities of enzymes related to cellular immunity, humoral immunity, and antioxidants, along with a notable upregulation in the expression of related genes, significantly increased. After V. parahaemolyticus challenge, the cumulative survival rates of the shrimp demonstrated a positive correlation with elevated concentrations of phlorotannins. In addition, the abundance of Bacteroidetes and functional genes associated with metabolism increased in phlorotannins supplementation groups. Phlorotannins did not elicit any detrimental effects on the biological macromolecules or histological integrity of the hepatopancreas or intestines. Simultaneously, it led to a significant reduction in malondialdehyde content. All results indicated that phlorotannins at concentrations of 2.0 g kg-1 can be used as safe feed additives to promote the growth, stimulate the immune response, improve the antioxidant capacity and intestinal health of L. vannamei, and an protect shrimp from damage caused by oxidative stress.

Real-world effectiveness of a new powered stapling system with gripping surface technology on the intraoperative clinical and economic outcomes of gastrectomy for gastric cancer.

BACKGROUND: Surgical staplers have been widely used to facilitate surgeries, and this study aimed to examine the real-world effectiveness of a new powered stapling system with Gripping Surface Technology (GST) on intraoperative outcomes of gastrectomy for gastric cancer. METHOD: The data were extracted from the Fourth Hospital of Hebei Medical University's (FHHMU) medical records system. Participants (N = 121 patients) were classified into the GST (n = 59) or non-GST group (n = 62), based on the use of the GST system. The intraoperative outcomes such as bleeding were assessed by reviewing video records. T-tests, Chi-square tests, and Mann-Whitney-U tests were used to compare the baseline characteristics between groups. Multivariate logistic regression was conducted for adjusting outcomes to study the effect of variables. RESULTS: Compared with the non-GST group, the GST group had significantly lower risks for intraoperative bleeding, intraoperative anastomosis intervention rate, intraoperative suture, and intraoperative pression (aORs: 0.0853 (p < 0.0001), 0.076 (p = 0.0003), 0.167 (p = 0.0012), and 0.221 (p = 0.0107), respectively). The GST group also consumed one fewer cartridge than the non-GST group (GST:5 vs non-GST: 6, p = 0.0241). CONCLUSION: The use of the GST system was associated with better intraoperative outcomes and lower cartridge consumption in Chinese real-world settings.

Interactions between inhalable aged microplastics and lung surfactant: Potential pulmonary health risks.

The relationship between microplastics (MPs) and human respiratory health has garnered significant attention since inhalation constitutes the primary pathway for atmospheric MP exposure. While recent studies have revealed respiratory risks associated with MPs, virgin MPs used as plastic surrogates in these experiments did not represent the MPs that occur naturally and that undergo aging effects. Thus, the effects of aged MPs on respiratory health remain unknown. We herein analyzed the interaction between inhalable aged MPs with lung surfactant (LS) extracted from porcine lungs vis-à-vis interfacial chemistry employing in-vitro experiments, and explored oxidative damage induced by aged MPs in simulated lung fluid (SLF) and the underlying mechanisms of action. Our results showed that aged MPs significantly increased the surface tension of the LS, accompanied by a diminution in its foaming ability. The stronger adsorptive capacity of the aged MPs toward the phospholipids of LS appeared to produce increased surface tension, while the change in foaming ability might have resulted from a variation in the protein secondary structure and the adsorption of proteins onto MPs. The adsorption of phospholipid and protein components then led to the aggregation of MPs in SLF, where the aged MPs exhibited smaller hydrodynamic diameters in comparison with the unaged MPs, likely interacting with biomolecules in bodily fluids to exacerbate health hazards. Persistent free radicals were also formed on aged MPs, inducing the formation of reactive oxygen species such as superoxide radicals (O2•-), hydrogen peroxide (HOOH), and hydroxyl radicals (•OH); this would lead to LS lipid peroxidation and protein damage and increase the risk of respiratory disease. Our investigation was the first-ever to reveal a potential toxic effect of aged MPs and their actions on the human respiratory system, of great significance in understanding the risk of inhaled MPs on lung health.

Nutritional supplement induced modulations in the functional connectivity of a porcine brain.

BACKGROUND: Functional connectivity (FC) measures statistical dependence between cortical brain regions. Studies of FC facilitate understanding of the brain's function and architecture that underpin normal cognition, behavior, and changes associated with various factors (e.g. nutritional supplements) at a large scale. OBJECTIVE: We aimed to identify modifications in FC patterns and targeted brain anatomies in piglets following perinatal intake of different nutritional diets using a graph theory based approach. METHODS: Forty-four piglets from four groups of pregnant sows, who were treated with nutritional supplements, including control diet, docosahexaenoic acid (DHA), egg yolk (EGG), and DHA + EGG, went through resting-state functional magnetic resonance imaging (rs-fMRI). We introduced the use of differential degree test (DDT) to identify differentially connected edges (DCEs). Simulation studies were first conducted to compare the DDT with permutation test, using three network structures at different noise levels. DDT was then applied to rs-fMRI data acquired from piglets. RESULTS: In simulations, the DDT showed a greater accuracy in detecting DCEs when compared with the permutation test. For empirical data, we found that the strength of internodal connectivity is significantly increased for more than 6% of edges in the EGG group and more than 8% of edges in the DHA and DHA + EGG groups, all compared to the control group. Moreover, differential wiring diagrams between group comparisons provided means to pinpoint brain hubs affected by nutritional supplements. CONCLUSION: DDT showed a greater accuracy of detection of DCEs and demonstrated EGG, DHA, and DHA + EGG supplemented diets lead to an improved internodal connectivity in the developing piglet brain.

Correlation Between Central Vein Smoke Ultrasonography and Thrombus Elasticity Graphy in Severe Patients.

Objective: The objective of this study was to analyze the correlation between central vein smoke ultrasonography (CVSU) and thrombus elasticity graphy (TEG). Methods: A retrospective analysis was made on 300 severe patients with smoky echo changes (SECs) in the internal jugular and femoral veins who were admitted to the hospital from January 2021 to March 2022. According to the ultrasound results, all patients were divided into Group A (n = 75), Group B (n = 75), Group C (n = 75), and Group D (n = 75). TEG examination, ultrasound examination, routine coagulation test were received. The coagulation function and TEG index were compared and analyzed in each group, and their correlation was analyzed. Results: The trends of R value and K value of TEG index of patients in different groups were the same. The R value and K value in group D were the highest, followed by group C, and the lowest in group A; while those in groups C and D exhibited great differences with P < .05 to those in groups A and B. The PT, TT, APTT, and FIB of patients in groups C and D were much higher based on the values in groups A and B. R-value was positively correlated with APACHEII (0.678), TT (0.198), and APTT (0.187), and negatively associated with PT (-0.008), D-D (-0.315), and FDP (-0.298). K value presented a positive correlation with APACHEII (0.692) and TT (0.342) but a negative correlation with PT (-0.187), APTT (-0.053), D-D (-0.497), and FDP (-0.453). Positive correlations were observed between α and PT (0.198), APTT (0.046), D-D (0.602), and FDP (0.532), while negative correlations were found between α and APACHEII (-0.398) and TT (-0.315). MA was positively correlated with PT, D-D, and FDP but negatively with APACHEII, TT, and APTT. Conclusion: TEG parameters had an obvious correlation with the coagulation function test, which can effectively evaluate the CVSU in severe patients. The ultrasonic signs can be undertaken as clinical hypercoagulability detection indicators in severe patients and intervention indicators for early thrombosis prevention in the future, they can guide clinicians to make the best treatment plan for severe patients.

CRISPR/Cas9-mediated ebony knockout causes melanin pigmentation and prevents moth Eclosion in Ectropis grisescens.

Ectropis grisescens (Lepidoptera: Geometridae) is a destructive tea pest in China. Mimesis, characterized by changing body color, is an important trait of E. grisescens larvae. Hence, identifying melanin pathway-related genes may contribute to developing new pest control strategies. In the present study, we cloned Egebony, a gene potentially involved in melanin pigmentation in E. grisescens, and subsequently conducted CRISPR/Cas9-mediated targeted mutagenesis of Egebony to analyze its role in pigmentation and development. At the larvae, prepupae, and pupae stages, Egebony-knockout individuals exhibited darker pigmentation than the wild-type. However, Egebony knockout did not impact the colors of sclerotized appendants, including ocelli, setae, and claws. While mutant pupae could successfully develop into moths, they were unable to emerge from the puparium. Notably, embryo hatchability and larval survival of mutants remained normal. Further investigation indicated that mutant pupae exhibited significantly stronger shearing force than the wild-type, with the pigmented layer of mutant pupae appearing darker and thicker. Collectively, these results suggest that the loss of Egebony might increase the rigidity of the puparium and prevent moth eclosion. This study provides new insights into understanding the function and diversification of ebony in insect development and identifies a lethal gene that can be manipulated for developing effective pest control strategies.

Wingtip-Flexible N-Heterocyclic Carbenes: Unsymmetrical Connection between IMes and IPr.

IMes (IMes=1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene) and IPr (IPr=1,3- bis(2,6-diisopropylphenyl)imidazol-2-ylidene) represent by far the most frequently used N-heterocyclic carbene ligands in homogeneous catalysis, however, despite numerous advantages, these ligands are limited by the lack of steric flexibility of catalytic pockets. We report a new class of unique unsymmetrical N-heterocyclic carbene ligands that are characterized by freely-rotatable N-aromatic wingtips in the imidazol-2-ylidene architecture. The combination of rotatable N-CH2 Ar bond with conformationally-fixed N-Ar linkage results in a highly modular ligand topology, entering the range of geometries inaccessible to IMes and IPr. These ligands are highly reactive in Cu(I)-catalyzed ß-hydroboration, an archetypal borylcupration process that has had a transformative impact on the synthesis of boron-containing compounds. The most reactive Cu(I)-NHC in this class has been commercialized in collaboration with MilliporeSigma to enable broad access of the synthetic chemistry community. The ligands gradually cover %Vbur geometries ranging from 37.3 % to 52.7 %, with the latter representing the largest %Vbur described for an IPr analogue, while retaining full flexibility of N-wingtip. Considering the modular access to novel geometrical space in N-heterocyclic carbene catalysis, we anticipate that this concept will enable new opportunities in organic synthesis, drug discovery and stabilization of reactive metal centers.

Protein phosphatase 2A regulates cytotoxicity and drug resistance by dephosphorylating AHR and MDR1.

Protein phosphatase 2A (PP2A) is a serine/threonine dephosphorylating enzyme complex that plays numerous roles in biological processes, including cell growth and metabolism. However, its specific actions in many of these critical pathways are unclear. To explore mechanisms underlying metabolic enzyme regulation in the liver, we investigated the key pathways involved in regulation of xenobiotic-metabolizing enzymes in a mouse model with hepatocyte-specific deletion of Ppp2r1a, encoding the Aα subunit of PP2A. We performed transcriptome and phosphoproteome analysis in mouse livers at the age of 3 months and identified 2695 differentially expressed genes and 549 upregulated phosphoproteins in homozygous knockout mouse livers compared with WT littermates. In particular, the expression of metabolic enzymes Cyp2e1, Cyp1a1, Cyp1a2, Mdr1a, and Abcg2 was dramatically altered in homozygous knockout mouse livers. We also demonstrated that activation of PP2A reversed the decline of metabolic enzyme expression in primary mouse hepatocytes. We found that specific PP2A holoenzymes were involved in metabolic enzyme induction through dephosphorylation of transcription factors, nuclear receptors, or the target enzymes themselves, leading to dysregulation of xenobiotic metabolism or drug-induced hepatotoxicity. Notably, we confirmed that a regulatory axis, PP2A B56α-aryl hydrocarbon receptor-Cyp1a1, was involved in benzo(a)pyrene-induced cytotoxicity through dephosphorylation of the metabolic nuclear receptor, aryl hydrocarbon receptor, at serine 36. In addition, we showed that PP2A B56δ complexes directly dephosphorylated the multidrug efflux pump MDR1 (encoded by multi-drug resistance gene 1), contributing to drug resistance against the chemotherapeutic 5-fluorouracil. Taken together, these novel findings demonstrate the involvement of PP2A in the regulation of liver metabolism.

Ino80 is required for H2A.Z eviction from hypha-specific promoters and hyphal development of Candida albicans.

ATP-dependent chromatin remodeling complexes play important roles in many essential cellular processes, including transcription regulation, DNA replication, and repair. Evicting H2A.Z, a variant of histone H2A, from the promoter of hypha-specific genes is required for hyphal formation in Candida albicans. However, the mechanism that regulates H2A.Z removal during hyphal formation remains unknown. In this study, we demonstrated that Ino80, the core catalytic subunit of the INO80 complex, was recruited to hypha-specific promoters during hyphal induction in Arp8 dependent manner and facilitated the removal of H2A.Z. Deleting INO80 or mutating the ATPase site of Ino80 impairs the expression of hypha-specific genes (HSGs) and hyphal development. In addition, we showed that Ino80 was essential for the virulence of C. albicans during systemic infections in mice. Interestingly, Arp5, an INO80 complex-specific component, acts in concert with Ino80 during DNA damage responses but is dispensable for hyphal induction. Our findings clarified that Ino80 was critical for hyphal development, DNA damage response, and pathogenesis in C. albicans.

Improved Cross-Linking Coverage for Protein Complexes Containing Low Levels of Lysine by Using an Enrichable Photo-Cross-Linker.

Chemical cross-linking coupled with mass spectrometry (XL-MS) is an important technique for the structural analysis of protein complexes where the coverage of amino acids and the identification of cross-linked sites are crucial. Photo-cross-linking has multisite reactivity and is valuable for the structural analysis of chemical cross-linking. However, a high degree of heterogeneity results from this multisite reactivity, which results in samples with higher complexity and lower abundance. Additionally, the applicability of photo-cross-linking is limited to purified protein complexes. In this work, we demonstrate a photo-cross-linker, alkynyl-succinimidyl-diazirine (ASD) with the reactive groups of N-hydroxysuccinimide ester and diazirine, as well as the click-enrichable alkyne group. Photo-cross-linkers can provide higher site reactivity for proteins that contain only a small number of lysine residues, thereby complementing the more commonly used lysine-targeting cross-linkers. By systematically analyzing proteins with differing lysine contents and differing flexibilities, we demonstrated clear enhancement in structure elucidation for proteins containing less lysine and with high flexibility. In addition, enrichment approaches of alkynyl-azide click chemistry conjugated with biotin-streptavidin purification (coinciding with parallel orthogonal digestion) improved the identification coverage of cross-links. We show that this photo-cross-linking approach can be used for membrane proteome-wide complex analysis. This method led to the identification of a total of 14066 lysine-X cross-linked site pairs from a total of 2784 proteins. Thus, this cross-linker is a valuable addition to a photo-cross-linking toolkit and improves the identification coverage of XL-MS in functional structure analysis.

Crosslinker Nanocarriers Delivery to Chloroplasts for In Vivo Mapping of Photosynthetic Membrane Protein Complexes in Living Chlamydomonas reinhardtii Cells.

Photosynthesis, as the core of solar energy biotransformation, is driven by photosynthetic membrane protein complexes in plants and algae. Current methods for intracellular photosynthetic membrane protein complex analysis mostly require the separation of specific chloroplasts or the change of the intracellular environment, which causes the missing of real-time and on-site information. Thus, we explored a method for in vivo crosslinking and mapping of photosynthetic membrane protein complexes in the chloroplasts of living Chlamydomonas reinhardtii (C. reinhardtii) cells under cultural conditions. Poly(lactic-co-glycolic acid) (PLGA) and poly(lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG) nanoparticles were fabricated to deliver bis(succinimidyl)propargyl with a nitro compound (BSPNO) into the chloroplasts to crosslink photosynthetic membrane protein complexes. After the in vivo crosslinked protein complexes were extracted and digested, mass spectrometry was employed to detect lysine-specific crosslinked peptides for further elucidating the protein conformations and interactions. With this method, the weak interactions between extrinsic proteins in the luminal side (PsbL and PsbH) and the core subunits (CP47 and CP43) in photosynthetic protein complexes were directly captured in living cells. Additionally, the previously uncharacterized protein (Cre07.g335700) was bound to the light-harvesting proteins, which was related to the biosynthesis of light-harvesting antennae. These results indicated that in vivo analysis of photosynthetic protein complexes based on crosslinker nanocarriers was expected to not only figure out the difficulty in the study of photosynthetic protein complexes in living cells but also provide an approach to explore transient and weak interactions and the function of uncharacterized proteins.

ON-OFF Fluorescent Cyanine Dye Based on a Benzothiophenyl Rotor Enables Selective Illumination of G-Quadruplexes in Mitochondria.

Conventional cyanine dyes exist as "always-on" fluorescent probes leading to inevitable background signals which often limit their performance and scope of applications. To develop specific fluorescent probes with high sensitivity and robust OFF/ON switching for targeting G4s, we introduced aromatic heterocycles through conjugation with polymethine chains to construct a rotor-π system. Here, a universal strategy is presented to synthesize pentamethine cyanines with different aromatic heterocycle substituents on the meso-polymethine chain. In these probes, SN-Cy5-S is self-quenched in aqueous solution due to H-aggregation. The structure indicates that SN-Cy5-S with a flexible meso-benzothiophenyl rotor conjugated to the cyanine backbone matches adaptively with G-tetrad planes, enhancing π-π stacking and resulting in triggered fluorescence. This allows recognition of G-quadruplexes due to the synergy of disaggregation-induced emission (DIE) and inhibited twisted intramolecular charge-transfer effects. This combination leads to a robust lighting-up fluorescence response for c-myc G4 with superior fluorescence enhancement (98-fold), allowing for a low detection limit of 1.51 nM, which is much more sensitive than the previously reported DIE-based G4 probes (22-83.5 nM). In addition, the superior imaging properties and rapid internalization time (5 min) in mitochondria allow SN-Cy5-S to also have a high potential for mitochondrially targeting anti-cancer therapy.

Developing an Affinity-Based Chemical Proteomics Method to In Situ Capture Amorphous Aggregated Proteome and Profile Its Heterogeneity in Stressed Cells.

Stress induced amorphous proteome aggregation is a hallmark for diseased cells, with the proteomic composition intimately associated with disease pathogenicity. Due to its particularly dynamic, reversible, and dissociable nature, as well as lack of specific recognition anchor, it is difficult to capture aggregated proteins in situ. In this work, we develop a chemical proteomics method (AggLink) to capture amorphous aggregated proteins in live stressed cells and identify the proteomic contents using LC-MS/MS. Our method relies on an affinity-based chemical probe (AggLink 1.0) that is optimized to selectively bind to and covalently label amorphous aggregated proteins in live stressed cells. Especially, chaotrope-compatible ligation enables effective enrichment of labeled aggregated proteins under urea denaturation and dissociation conditions. Compared to conventional fractionation-based method to profile aggregated proteome, our method showed improved enrichment selectivity, detection sensitivity, and identification accuracy. In HeLa cells, the AggLink method reveals the constituent heterogeneity of aggregated proteome induced by inhibition of pro-folding (HSP90) or pro-degradation (proteasome) pathway, which uncovers a synergistic strategy to reduce cancer cell viability. In addition, the unique fluorogenicity of our probe upon labeling aggregated proteome detects its cellular location and morphology. Together, the AggLink method may help to expand our knowledge of the previously nontargetable amorphous aggregated proteome.

Clinical implications of micro lymph node metastasis for patients with gastric cancer.

BACKGROUND: Lymph node size is considered as a criterion for possible lymph node metastasis in imageology. Micro lymph nodes are easily overlooked by surgeons and pathologists. This study investigated the influencing factors and prognosis of micro lymph node metastasis in gastric cancer. METHODS: 191 eligible gastric cancer patients who underwent D2 lymphadenectomy from June 2016 to June 2017 in the Third Surgery Department at the Fourth Hospital of Hebei Medical University were retrospectively analyzed. Specimens were resected en bloc and the postoperative retrieval of micro lymph nodes was carried out by the operating surgeon for each lymph node station. Micro lymph nodes were submitted for pathological examination separately. According to the results of pathological results, patients were divided into the "micro-LNM (micro lymph node metastasis)" group (N = 85) and the "non micro-LNM" group (N = 106). RESULTS: The total number of lymph nodes retrieved was 10,954, of which 2998 (27.37%) were micro lymph nodes. A total of 85 (44.50%) gastric cancer patients had been proven to have micro lymph node metastasis. The mean number of micro lymph nodes retrieved was 15.7. The rate of micro lymph node metastasis was 8.1% (242/2998). Undifferentiated carcinoma (90.6% vs. 56.6%, P = 0.034) and more advanced Pathological N category (P < 0.001) were significantly related to micro lymph node metastasis. The patients with micro lymph node metastasis had a poor prognosis (HR for OS of 2.199, 95% CI = 1.335-3.622, P = 0.002). For the stage III patients, micro lymph node metastasis was associated with shorter 5-year OS (15.6% vs. 43.6%, P = 0.0004). CONCLUSIONS: Micro lymph node metastasis is an independent risk factor for poor prognosis in gastric cancer patients. Micro lymph node metastasis appears to be a supplement to N category in order to obtain more accurate pathological staging.

IL1RAP Knockdown in LPS-Stimulated Normal Human Astrocytes Suppresses LPS-Induced Reactive Astrogliosis and Promotes Neuronal Cell Proliferation.

The reactivation of astrocytes plays a critical role in spinal cord injury (SCI) repairment. In this study, IL1RAP expression has been found to be upregulated in SCI mice spinal cord, SCI astrocytes, and LPS-stimulated NHAs. Genes correlated with IL1RAP were significantly enriched in cell proliferation relative pathways. In LPS-stimulated NHAs, IL1RAP overexpression promoted NHA cell proliferation, decreased PTEN protein levels, and increased the phosphorylation of Akt and mTOR. IL1RAP overexpression promoted LPS-induced NHA activation and NF-κB signaling activation. Conditioned medium from IL1RAP-overexpressing NHAs inhibited SH-SY5Y cells viability but promoted cell apoptosis. Conclusively, IL1RAP knockdown in LPS-stimulated NHAs could partially suppress LPS-induced reactive astrogliosis, therefore promoting neuronal cell proliferation.