Mechanism of Peptide Self-assembly and Its Study in Biomedicine

The development of peptide-based materials is one of the most challenging aspects of biomaterials research in recent years. The assembly of peptides is mainly controlled by forces such as hydrogen bonding, hydrophobic interaction, electrostatic interaction, and π-π accumulation. Peptides have unique advantages such as simple structure, easy synthesis, good biocompatibility, non-toxicity, easy modification, etc. These factors make peptides turn into ideal biomedical materials, and they have a broad application prospect in biomedical materials, and thus have received wide attention. In this review, the mechanism and classification of peptide self-assembly and its applications in biomedicine and hydrogels were introduced.

Gelation Behavior and Drug Sustained-Release Properties of a Helix Peptide Organohydrogel with pH Responsiveness

Based on the typical similar repeat units (abcdefg)n of α-helical structure, the peptide H was designed to self-assemble into an organohydrogel in response to pH. Depending on the different pH, the proportions of secondary structure, microstructure, and mechanical properties of the gel were investigated. Circular dichroism (CD) and Fourier transform infrared (FT-IR) showed that the proportion of α-helical structure gradually increased to become dominant with the increase of pH. Combining transmission electron microscopy (TEM) and atomic force microscopy (AFM), it was found that the increase of the ordered α-helix structure promoted fiber formation. The further increase in pH changed the intermolecular forces, resulting in an increase in the α-helix content and the enhancement of helix-helix interaction, causing the gel fibers to converge into thicker and more dense ones. The temperature test showed the stable rheological properties of the organohydrogel between 20-60 °C. Drug release and cytotoxicity showed that the DOX-loaded organohydrogel could have a better release in an acidic environment, indicating its potential application as a drug local delivery carrier.

[Constructing an early-warning model for mortality risk in heat stroke patients based on Fisher discriminant analysis]

Objective: To establish an early warning model to assess the mortality risk of patients with heat stroke disease. Methods: The case data of patients diagnosed with heat stroke disease admitted to the comprehensive ICU of Shanshan County from January 2016 to December 2020 were selected. According to the short-term outcome (28 days) of patients, they were divided into death group (20 cases) and survival group (53 cases) . The relevant indicators with statistically significant differences between groups within 24 hours after admission were selected. By drawing the subject work curve (ROC) and calculating the area under the curve, the relevant indicators with the area under the curve greater than 0.7 were selected, Fisher discriminant analysis was used to establish an assessment model for the death risk of heat stroke disease. The data of heat stroke patients from January 1, 2021 to December 2022 in the comprehensive ICU of Shanshan County were collected for external verification. Results There were significant differences in age, cystatin C, procalcitonin, platelet count, CKMB, CK, CREA, PT, TT, APTT, heart rate, respiratory rate and GLS score among the groups. Cystatin C, CKMB, CREA, PT, TT, heart rate AUC area at admission was greater than 0.7. Fisher analysis method is used to build a functional model. Results: The diagnostic sensitivity, specificity and AUC area of the functional model were 95%, 83% and 0.937 respectively. The external validation results showed that the accuracy of predicting survival group was 85.71%, the accuracy of predicting death group was 88.89%. Conclusion: The early warning model of heat stroke death constructed by ROC curve analysis and Fisher discriminant analysis can provide objective reference for early intervention of heat stroke.

Stabilizing Supersaturation with Extreme Grain Refinement in Spinodal Aluminum Alloys

Supersaturated solid solutions can be formed in alloys from various non-equilibrium processes, but stabilizing the metastable phases against decomposition is challenging, particularly the spinodal decomposition that occurs via chemical fluctuations without energy barriers to nucleation. In this work, it is found that spinodal decomposition in supersaturated Al(Zn) solid solutions can be inhibited with straining-induced extreme grain refinement. For the refined supersaturated grains at the nanoscale, their spinodal decomposition is obviously resisted by the relaxed grain boundaries and reduced lattice defects. As grains are refined below 10 nm the decomposition is completely inhibited, in which atomic diffusion is blocked by the stable Schwarz crystal structure with vacancy-free grains. Extreme grain refinement offers a general approach to stabilize supersaturated phases with broadened compositional windows for property modulation of alloys.

Interaction of Cecropin A (1-7) Analogs with DNA Analyzed by Multi-spectroscopic Methods

Cecropin A (1-7) is a cationic antimicrobial peptide which contain lots of basic amino acids. To understand the effect of basic amino acids on cecropin A (1-7), analogues CA2, CA3 and CA4 which have more arginine or lysine at the N-terminal or C-terminal were designed and synthesized. The interaction of cecropin A (1-7) and its analogs with DNA was studied using ultraviolet-visible spectroscopy, fluorescence spectroscopy and circular dichroism spectroscopy. Multispectral analysis showed that basic amino acids improved the interaction between the analogues and DNA. The interaction between CA4 and DNA is most pronounced. Fluorescence spectrum indicated that Ksv value of CA4 is 1.19 × 105  L mol-1 compared to original peptide cecropin A (1-7) of 3.73 × 104  L mol-1. The results of antimicrobial experiments with cecropin A (1-7) and its analogues showed that basic amino acids enhanced the antimicrobial effect of the analogues. The antimicrobial activity of CA4 against E. coli was eightfold higher than that of cecropin A (1-7). The importance of basic amino acid in peptides is revealed and provides useful information for subsequent studies of antimicrobial peptides.

A mix & act liposomes of phospholipase A2-phosphatidylserine for acute brain detoxification by blood‒brain barrier selective-opening

In the treatment of central nervous system disease, the blood-brain barrier (BBB) is a major obstruction to drug delivery that must be overcome. In this study, we propose a brain-targeted delivery strategy based on selective opening of the BBB. This strategy allows some simple bare nanoparticles to enter the brain when mixed with special opening material; however, the BBB still maintains the ability to completely block molecules from passing through. Based on the screening of BBB opening and matrix delivery materials, we determined that phospholipase A2-catalyzed 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoserine liposomes can efficiently carry drugs into the brain immediately. At an effective dose, this delivery system is safe, especially with its effect on the BBB being reversible. This mix & act delivery system has a simple structure and rapid preparation, making it a strong potential candidate for drug delivery across the BBB.

Double pyramid stacked CoO nano-crystals induced by graphene at low temperatures as highly efficient Fenton-like catalysts

Transition metal oxides are widely used as Fenton-like catalysts in the treatment of organic pollutants, but their synthesis usually requires a high temperature. Herein, an all-solid-state synthesis method controlled by graphene was used to prepare a double pyramid stacked CoO nano-crystal at a low temperature. The preparation temperature decreased by 200 °C (over 30% reduction) due to the introduction of graphene, largely reducing the reaction energy barrier. Interestingly, the corresponding degradation rate constants (kobs) of this graphene-supported pyramid CoO nano-crystals for organic molecules after their adsorption were over 2.5 and 35 times higher than that before adsorption and that of free CoO, respectively. This high catalytic efficiency is attributed to the adsorption of pollutants at the surface by supporting graphene layers, while free radicals activated by CoO can directly and rapidly contact and degrade them. These findings provide a new strategy to prepare low carbon-consuming transition metal oxides for highly efficient Fenton-like catalysts.

Copper-catalyzed thiocyanation of cyclobutanone oxime esters using ammonium thiocyanate

A copper-catalyzed thiocyanation of cycloketone oxime esters with ammonium thiocyanate has been developed for the first time. This innovative approach allows access to cyano and thiocyano bifunctionally substituted alkanes, which can be further transformed into their respective trifluoromethylthiol-substituted or difluoromethylthiol-substituted alkylnitriles, alkynyl sulfides, and phosphorothioate esters. The readily available nature of ammonium thiocyanate and the cost-effectiveness of the copper catalyst make this method a promising strategy for the synthesis of sulfur-containing alkylnitriles.

Vegetation-fire feedbacks increase subtropical wildfire risk in scrubland and reduce it in forests

Climate dictates wildfire activity around the world. But East and Southeast Asia are an apparent exception as fire-activity variation there is unrelated to climatic variables. In subtropical China, fire activity decreased by 80% between 2003 and 2020 amid increased fire risks globally. Here, we assessed the fire regime, vegetation structure, fuel flammability and their interactions across subtropical Hubei, China. We show that tree basal area (TBA) and fuel flammability explained 60% of fire-frequency variance. Fire frequency and fuel flammability, in turn, explained 90% of TBA variance. These results reveal a novel system of scrubland-forest stabilized by vegetation-fire feedbacks. Frequent fires promote the persistence of derelict scrubland through positive vegetation-fire feedbacks; in forest, vegetation-fire feedbacks are negative and suppress fire. Thus, we attribute the decrease in wildfire activity to reforestation programs that concurrently increase forest coverage and foster negative vegetation-fire feedbacks that suppress wildfire.

Photochemical Difluoromethylation of Quinoxalin-2(1H)-ones with Difluoroacetic Anhydride and Pyridine N-Oxide

A novel photochemical difluoromethylation of quinoxalin-2(1H)-ones under catalyst-free conditions was achieved with difluoroacetic anhydride and pyridine N-oxide. The green and mild reaction conditions as well as readily attainable difluoroacetic anhydride provide a useful protocol to prepare C3-difluoromethylated quinoxalin-2(1H)-ones.

Synthesis and mechanism of action of new purine derivatives against triple negative breast cancer

Triple negative breast cancer (TNBC) is considered to be the most difficult subtype of breast cancer to treat because of its extremely prone to metastasis and the lack of targeted therapy drugs. New purine derivatives were synthesized and evaluated in a series of kinases and cell lines. The most active compounds 3g and 3j were selected based on their antiproliferative activities, then their pharmaceutical activity and mechanism in MDA-MB-231 cells were analyzed. The results in vitro indicated that compounds 3g and 3j can induce MDA-MB-231 cells apoptosis, and inhibit its migration and angiogenesis through influencing protein expression such as Bcl-2, Bax, Bcl-xl, P38, MMP2, MMP9, AKT and EGFR. In vivo results indicate that compounds 3g and 3j can inhibit tumor growth and metastasis and reduce the expression of Ki67 and CD31 protein in TNBC xenograft models. These findings not only broaden our understanding of the anti-TNBC effects and mechanisms of compounds 3g and 3j, but also provide new ideas and reference directions for the treatment of TNBC.

Association between serum iron, blood lead, cadmium, mercury, selenium, manganese and low cognitive performance in old adults from National Health and Nutrition Examination Survey (NHANES): a cross-sectional study

Cognitive decline is a public health problem for the world's ageing population. This study was to evaluate the relationships between serum Fe, blood Pb, Cd, Hg, Se and Mn and cognitive decline in elderly Americans. Data of this cross-sectional study were extracted from the National Health and Nutritional Examination Survey (NHANES 2011-2014). Cognitive performance was measured by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), Animal Fluency and Digit Symbol Substitution Test (DSST) tests. Weighted univariable and multivariate logistic regression analyses were used to assess the associations between six trace elements and low cognitive performance. Subgroup analyses based on diabetes and hypertension history were further assessed the associations. A total of 2002 adults over 60 years old were included. After adjusting covariates, elevated serum Fe levels were associated with the decreased risk of low cognitive performance, especially in the elderly without diabetes history and with hypertension history. High blood Cd levels were associated with the high odds of low cognitive performance in old adults with diabetes and hypertension history. Elevated blood Mn levels were connected with low cognitive performance in old hypertensive people. High blood Pb levels were related to the high odds of low cognitive performance, especially in the elderly without diabetes and hypertension history. High blood Se levels were linked to the decreased risk of low cognitive performance in all the elderly. Appropriate Fe, Se supplementation and Fe-, Se-rich foods intake, while reducing exposure to Pb, Cd and Mn may be beneficial for cognitive function in the elderly.

Recent advances in the development of inhibitors targeting KRAS-G12C and its related pathways

The RAS gene, also known as the mouse sarcoma virus, includes three genes (KRAS, HRAS, and NRAS) that are associated with human tumors. Among them, KRAS has the highest incidence of mutations in cancer, accounting for around 80% of cases. At the molecular level, the RAS gene plays a regulatory role in transcription and translation, while at the cellular level, it affects cell proliferation and migration, making it crucial for cancer development. In 2021, the FDA approved AMG510, the first direct inhibitor targeting the KRAS-G12C mutation, which has shown tumor regression, prolonged survival, and low off-target activity. However, with the increase of drug resistance, a single inhibitor is no longer sufficient to achieve the desired effect on tumors. Therefore, a large number of other highly efficient inhibitors are being developed at different stages. This article provides an overview of the mechanism of action targeting KRAS-G12C in the KRASGTP-KRASGDP cycle pathway, as well as the structure-activity relationship, structure optimization, and biological activity effects of inhibitors that target the upstream and downstream pathways, or combination therapy.

Comparison of clinical outcomes in patients with acute ischemic stroke who underwent endovascular treatment using different perfusion modalities: a real-world multicenter study

Background

Advanced perfusion modalities are increasingly popular for various diseases. However, few studies have focused on contrasting perfusion patterns.

Objective

This study aimed to compare the time efficiency and clinical outcomes of patients with acute ischemic stroke (AIS) who underwent endovascular treatment (EVT) before one-stop arterial spin labeling (ASL) and computed tomography perfusion (CTP) protocols.

Methods

This study retrospectively included 326 patients with AIS who had accepted EVT within 24 h of onset from four comprehensive stroke centers between October 2017 and September 2022. After 1:1 matching of the propensity scores, 202 patients were separated into two groups: the ASL group (n = 101) and the CTP group (n = 101).

Results

Functional independence at 90 days (modified Rankin Scale [mRS] 0-2; p = 0.574), onset-to-puncture time (p = 0.231), door-to-puncture time (p = 0.136), and door-to-perfusion time (p = 0.646) were not significantly different between the two groups. The proportion of EVT complications (31.7% in the ASL group vs. 14.9% in the CTP group, p = 0.005) and symptomatic intracranial hemorrhage (sICH) at 24 h (23.8% in the ASL group vs. 9.9% in the CTP group, p = 0.008) in the CTP group were lower than the ASL group. The ischemic core volume was a common predictor of favorable outcomes in both ASL (p < 0.001) and CTP (p < 0.001) groups.

Conclusion

There were no significant differences in time efficiency and efficacy outcomes between the two groups of patients receiving one-stop ASL and CTP. The proportion of sICH at 24 h and EVT complications of patients in the CTP group was lower than the ASL group. The ischemic core volume was an independent predictor for favorable outcomes.

Mechanisms and influencing factors of peptide hydrogel formation and biomedicine applications of hydrogels

Self-assembled peptide-based hydrogels have shown great potential in bio-related applications due to their porous structure, strong mechanical stability, high biocompatibility, and easy functionalization. Herein, the structure and characteristics of hydrogels and the mechanism of action of several regular secondary structures during gelation are investigated. The factors influencing the formation of peptide hydrogels, especially the pH responsiveness and salt ion induction are analyzed and summarized. Finally, the biomedical applications of peptide hydrogels, such as bone tissue engineering, cell culture, antigen presentation, antibacterial materials, and drug delivery are reviewed.

The impact of acute-phase reaction on mortality and re-fracture after zoledronic acid in hospitalized elderly osteoporotic fracture patients

This study involving 674 elderly osteoporotic fracture (OPF) patients undergoing orthopedic surgery investigated the long-term outcomes of acute phase reaction (APR) after initial zoledronic acid (ZOL). Those who had an APR had a 97% higher risk of mortality and a 73% lower rate of re-fracture than patients who did not.

INTRODUCTION

Annual infusion of ZOL efficiently decreases the risk of fracture. A temporary APR, consisting of flu-like symptoms, myalgia, and fever, is frequently observed within 3 days after the first dose. This work aimed to identify whether the occurrence of APR after initial ZOL infusion is a reliable indicator of drug efficacy for mortality and re-fracture in elderly OPF patients undergoing orthopedic surgery.

METHODS

This retrospectively observed work was constructed on a database prospectively collected from the Osteoporotic Fracture Registry System of a tertiary level A hospital in China. Six hundred seventy-four patients 50 years old or older with newly identified hip/morphological vertebral OPF who received ZOL for the first time after orthopedic surgery were included in the final analysis. APR was identified as a maximum axillary body temperature greater than 37.3 °C for the first 3 days after ZOL infusion. We utilized models of multivariate Cox proportional hazards to compare the risk of all-cause mortality in OPF patients with APR (APR+) and without APR (APR-). Competing risks regression analysis was used to examine the association between the occurrence of APR and re-fracture when mortality was taken into account.

RESULTS

In a fully adjusted Cox proportional hazards model, APR+ patients had a significantly higher risk of death than APR- patients with a hazard ratio [HR] 1.97 (95% CI, 1.09-3.56; P-value = 0.02). Furthermore, in an adjusted competing risk regression analysis, APR+ patients had a significantly reduced risk of re-fracture compared with APR- patients with a sub-distribution HR, 0.27 (95% CI, 0.11-0.70; P-value = 0.007).

CONCLUSIONS

Our findings suggested a potential association between the occurrence of APR and increased mortality risk. An initial dose of ZOL following orthopedic surgery was found to be protective against re-fracture in older patients with OPFs.

[Efficacy and safety of bendamustine-rituximab combination therapy for newly diagnosed indolent B-cell non-Hodgkin's lymphoma and elderly mantle cell lymphoma: a multi-center prospective phase II clinical trial in China]

Objectives: This study aimed to assess the efficacy and safety of bendamustine in combination with rituximab (BR regimen) for the treatment of newly diagnosed indolent B-cell non-Hodgkin's lymphoma (B-iNHL) and elderly mantle cell lymphoma (eMCL) . Methods: From December 1, 2020 to September 10, 2022, a multi-center prospective study was conducted across ten Grade A tertiary hospitals in Shandong Province, China. The BR regimen was administered to evaluate its efficacy and safety in newly diagnosed B-iNHL and eMCL patients, and all completed at least four cycles of induction therapy. Results: The 72 enrolled patients with B-iNHL or MCL were aged 24-74 years, with a median age of 55 years. Eastern Cooperative Oncology Group (ECOG) performance status scores of 0-1 were observed in 76.4% of patients, while 23.6% had scores of 2. Disease distribution included follicular lymphoma (FL) (51.4% ), marginal zone lymphoma (MZL) (33.3% ), eMCL (11.1% ), and the unknown subtype (4.2% ). According to the Ann Arbor staging system, 16.7% and 65.3% of patients were diagnosed with stage Ⅲ and stage Ⅳ lymphomas, respectively. Following four cycles of BR induction therapy, the overall response rate was 98.6%, with a complete response (CR) rate of 83.3% and a partial response (PR) rate of 15.3%. Only one eMCL patient experienced disease progression during treatment, and only one FL patient experienced a relapse. Even when evaluated using CT alone, the CR rate was 63.9%, considering the differences between PET/CT and CT assessments. The median follow-up duration was 11 months (range: 4-22), with a PFS rate of 96.8% and an OS rate of 100.0%. The main hematologic adverse reactions included grade 3-4 leukopenia (27.8%, with febrile neutropenia observed in 8.3% of patients), grade 3-4 lymphopenia (23.6% ), grade 3-4 anemia (5.6% ), and grade 3-4 thrombocytopenia (4.2% ). The main non-hematologic adverse reactions such as fatigue, nausea/vomiting, rash, and infections occurred in less than 20.0% of patients. Conclusion: Within the scope of this clinical trial conducted in China, the BR regimen demonstrated efficacy and safety in treating newly diagnosed B-iNHL and eMCL patients.

The predictive value of CD4, CD8, and C-reactive protein in the prognosis of schistosomal and non-schistosomal colorectal cancer

BACKGROUND

Although schistosomiasis has been basically eliminated, it has not been completely extinction in China and occasional outbreaks occur in Europe in recent years. The relationship between inflammation caused by Schistosoma japonicum and colorectal cancer (CRC) is still obscure, and the inflammation based prognostic systems of schistosomal colorectal (SCRC) has rarely been reported.

AIM

To explore the different roles of tumor infiltrating lymphocytes (TILs) and C-reactive protein (CRP) in SCRC and in Non-schistosomal CRC (NSCRC), providing a possible predictive system to evaluate outcomes and to improve the risk stratification for CRC patients, especially for CRC patients with schistosomiasis.

METHODS

Three hundred fifty-one CRC tumors were evaluated for density of CD4 + , CD8 + T cells and CRP in intratumoral and stromal compartments by immunohistochemical using tissue microarray.

RESULTS

There were no association between TILs and CRP and schistosomiasis. Multivariate analysis identified stromal CD4 (sCD4) (p = 0.038), intratumoral CD8 (iCD8) (p = 0.003), schistosomiasis (p = 0.045) as independent prognostic factors for overall survival (OS) in the whole cohort; and sCD4 (p = 0.006) and iCD8 (p = 0.020) were independent prognostic factors for OS in the NSCRC and SCRC set, respectively. Besides, we found that there were no differences of TILs and CRP, which were distributed in different areas of tumor tissue, between CRC patients with and without schistosomiasis.

CONCLUSION

The results remind us that different subtypes of TILs have distinguished biological behavior and prognosis value in the immune microenvironment of NSCRC and SCRC patients. Meanwhile, the findings require us to stratify patients with schistosomiasis and this might facilitate patient counseling and management.

Spectroscopic studies on noncovalent binding of nicotinamide-modified BRCA1 (856-871) analogs to calf thymus DNA

Various peptide drugs have entered the market with the development of molecular biology. Peptide drugs are used for treat diseases such as diabetes, breast cancer, and HIV infection. In this study, three nicotinamide-modified peptides were synthesized by modifying the N-terminus of BRCA1 (856-871, Y856R, K862Y, R866W) peptide with three nicotinic acid derivatives using solid-phase peptide synthesis. The results of calf thymus DNA (ctDNA) binding activity indicated that binding constants of BRCA1 (856-871, Y856R, K862Y, R866W) (P0) and three nicotinamide-modified peptides (P1, P2, and P3) to ctDNA were 1.89 × 10³, 2.97 × 10⁴, 7.61 × 10⁴, and 8.09 × 10⁴ L·mol^-1, respectively. The binding affinity of the modified peptides was superior to that of BRCA1 (856-871, Y856R, K862Y, R866W). ΔH^θ < 0 and ΔS^θ < 0 indicated that van der Waals force and hydrogen bond contributed most to peptide-ctDNA binding. Results obtained by Circular dichroism (CD) indicated that peptide binding interaction led to conformational changes in ctDNA. Ultraviolet-visible (UV) spectroscopy, ethidium bromide (EB) competition experiments, DNA melting experiments, and viscosity measurements verified that peptides interacted with ctDNA via groove binding. Ionic strength experiments manifested that electrostatic binding was also involved in peptide-ctDNA binding.

Visible-light promoted cascade cyanoalkylsulfonylation/ipso-cyclization of N-arylpropiolamides toward sulfonated spiro[4,5]trienones via SO2 insertion

A novel visible-light induced sulfonylation/ipso-cyclization of N-arylpropiolamides with cyclobutanone oxime esters and Na₂S₂O₅ was reported. This protocol proceeded via a radical process. The wide substrate scope, sustainable metal-free conditions and readily accessible reagents make this protocol an efficient and green strategy for the synthesis of cyanoalkyl sulfonated spiro[4,5]trienones.

Copper-catalyzed ring-opening trifluoromethylthiolation/trifluoromethylselenolation of cyclopropanols with TsSCF3 or Se-(trifluoromethyl) 4-methoxybenzenesulfonoselenoate

We report a ring-opening trifluoromethylthiolation of cyclopropanols with TsSCF₃ by using Cu(OAc)₂ as the catalyst. Moreover, by using this strategy, the trifluoromethylselenolation of cyclopropanols with Se-(trifluoromethyl) 4-methoxybenzenesulfonoselenoate to access β-SeCF₃-substituted carbonyl compounds is achieved for the first time. The broad substrate scope, readily accessible reagents and cheap catalyst make this protocol an alternative and efficient method for the synthesis of β-SCF₃-substituted or β-SeCF₃-substituted carbonyl compounds.

Synthesis, molecular docking, and binding Gibbs free energy calculation of β-nitrostyrene derivatives: Potential inhibitors of SARS-CoV-2 3CL protease

The outbreak of novel coronavirus disease 2019 (COVID-19), caused by the novel coronavirus (SARS-CoV-2), has had a significant impact on human health and the economic development. SARS-CoV-2 3CL protease (3CLpro) is highly conserved and plays a key role in mediating the transcription of virus replication. It is an ideal target for the design and screening of anti-coronavirus drugs. In this work, seven β-nitrostyrene derivatives were synthesized by Henry reaction and β-dehydration reaction, and their inhibitory effects on SARS-CoV-2 3CL protease were identified by enzyme activity inhibition assay in vitro. Among them, 4-nitro-β-nitrostyrene (compound a) showed the lowest IC₅₀ values of 0.7297 μM. To investigate the key groups that determine the activity of β-nitrostyrene derivatives and their interaction mode with the receptor, the molecular docking using the CDOCKER protocol in Discovery Studio 2016 was performed. The results showed that the hydrogen bonds between β-NO₂ and receptor GLY-143 and the π-π stacking between the aryl ring of the ligand and the imidazole ring of receptor HIS-41 significantly contributed to the ligand activity. Furthermore, the ligand-receptor absolute binding Gibbs free energies were calculated using the Binding Affinity Tool (BAT.py) to verify its correlation with the activity of β-nitrostyrene 3CLpro inhibitors as a scoring function. The higher correlation(r²=0.6) indicates that the absolute binding Gibbs free energy based on molecular dynamics can be used to predict the activity of new β-nitrostyrene 3CLpro inhibitors. These results provide valuable insights for the functional group-based design, structure optimization and the discovery of high accuracy activity prediction means of anti-COVID-19 lead compounds.

Interaction of bifunctional peptide-carbazole complexes with DNA and antimicrobial activity

Two peptide-carbazole conjugates, CTAT and CNLS, were designed and synthesized using carbazole Schiff base to modify the cell membrane penetrating peptide TAT (47-57) and the nuclear localization peptide NLS at the N terminus. The interaction with ctDNA was investigated by multispectral and agarose gel electrophoresis. And the effects of CNLS and CTAT on the G-quadruplex structure were explored by circular dichroism titration experiments. The results show that both CTAT and CNLS interact with ctDNA in a minor groove binding manner. Both conjugates bind more tightly to DNA than the individual substances CIBA, TAT and NLS. In addition, CTAT and CNLS are capable of unfolding parallel G-quadruplex structures and are potential G-quadruplex unfolding agents. Finally, broth microdilution was performed to test the antimicrobial activity of the peptides. The results showed that CTAT and CNLS had a 4-fold increase in antimicrobial activity compared with the parent peptides TAT and NLS. They could exert antimicrobial activity by disrupting the integrity of cell membrane bilayer and binding to DNA, and could be used as novel antimicrobial peptides for the development of novel antimicrobial antibiotics.

Comparison of the prognostic value of stromal tumor-infiltrating lymphocytes and CD3 + T cells between schistosomal and non-schistosomal colorectal cancer

AIM

To compare the prognostic value of tumor-infiltrating lymphocytes (TILs) and CD3 + cells and CD20 + cells between schistosomal colorectal cancer (SCRC) and non-schistosomal CRC (NSCRC).

BACKGROUND

Although schistosomiasis has been basically eliminated, it has not been completely extinction in China, and occasional outbreaks occur in Europe recently. The role of immune cells in the immune microenvironment of SCRC and NSCRC is remaining obscure, and the inflammation-based prognostic systems of SCRC has rarely been reported.

METHODS

HE-stained sections of 349 colorectal cancer (CRC) tumors, which were completely resected, were evaluated for density of TILs. Meanwhile, we evaluated CD3 + T lymphocytes and CD20 + B lymphocytes by immunochemistry. The relationship of these infiltrating immune cells with clinicopathological features, including schistosomiasis, and clinical outcomes was evaluated, and the prognostic roles of TILs in SCRC and NSCRC were explored.

RESULTS

Except for age (P < 0.0001), there were no significant differences between NSCRC and SCRC patients in clinicopathological features (P > 0.05). Beside, the positive expression pattern of sTILs, iTILs, CD3, and CD20 between NSCRC and SCRC patients was also similar (P > 0.05). In the whole cohort, sTILs and CD3 were defined as independent prognostic factors (P = 0.031 and P = 0.003, respectively). CD3 was an independent prognostic factor both in the NSCRC and SCRC set (P = 0.026 and P = 0.045, respectively). Higher sTILs, CD3, and CD20 were correlated with less aggressive tumor characteristics in the whole cohort and in subgroups.

CONCLUSION

Although CD3 was an independent prognostic factor for both NSCRC and SCRC set, there were no significant differences between SCRC and NSCRC patients in sTILs, CD3, CD20, and in other clinicopathological features.

Cucurbit[n]uril-based fluorescent indicator-displacement assays for sensing organic compounds

The widespread conversion of synthetic receptors into luminescent sensors has been achieved via the use of fluorescent-indicator displacement assays (F-IDAs). Due to their rigid structures and efficient binding affinities, cucurbit[n]urils, combined with a variety of fluorescent guests, have gained extensive utilization in fluorescent-indicator displacement assays for sensing non-fluorescent or weakly fluorescent organic compounds (analytes) in a selective and specific manner. This mini-review summarizes recent advances in the design of cucurbit[n]uril-based fluorescent-indicator displacement assays and discusses the current challenges and future prospects in this area.

Visible-Light-Promoted Trifluoromethylthiolation and Trifluoromethylselenolation of 1,4-Dihydropyridines

We report a metal-free trifluoromethylthiolation and trifluoromethylselenolation of 1,4-dihydropyridines with S-(trifluoromethyl) 4-methylbenzenesulfonothioate and Se-(trifluoromethyl) 4-methylbenzenesulfonoselenoate under visible light irradiation. This transformation was tolerated with a wide range of functional groups and provided an alternative and green strategy for the synthesis of trifluoromethylthioesters and trifluoromethylselenoesters.

Visible-Light-Induced Difluoroalkylation of Alkenes and Alkynes with Fluoro-Containing Hypervalent Iodane (III) Reagents Under Photo-Catalyst-Free Conditions

A visible-light-induced difluoroalkylation of unactivated alkenes by fluoro-containing hypervalent iodine-based difluoroalkylation reagent was achieved for the first time under photo-catalyst-free conditions. Moreover, the same reaction conditions were applicable to the difluoroalkylation of alkynes to give the hydrodifluoroalkylation products in moderate to excellent yields. The readily available reagent, broad substrate scope, and photo-catalyst-free conditions make this protocol an efficient and environmental friendly method for the hydrodifluoroalkylation of alkenes and alkynes.

Synapsin 1 Ameliorates Cognitive Impairment and Neuroinflammation in Rats with Alzheimer's Disease: An Experimental and Bioinformatics Study

BACKGROUND

Alzheimer's disease (AD) is a persistent neuropathological injury that manifests via neuronal/synaptic death, age spot development, tau hyperphosphorylation, neuroinflammation, and apoptosis. Synapsin 1 (SYN1), a neuronal phosphoprotein, is believed to be responsible for the pathology of AD.

OBJECTIVE

This study aimed to elucidate the exact role of SYN1 in ameliorating AD and its potential regulatory mechanisms.

METHODS

The AD dataset GSE48350 was downloaded from the GEO database, and SYN1 was focused on differential expression analysis and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. After establishing an AD rat model, they were treated with RNAi lentivirus to trigger SYN1 overexpression. The amelioration of SYN1 in AD-associated behavior was validated using multiple experiments (water maze test and object recognition test). SYN1's repairing effect on the important factors in AD was confirmed by detecting the concentration of inflammatory factors (interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)-α), neurotransmitters (acetylcholine (ACh), dopamine (DA), and 5-hydroxytryptophan (5-HT)) and markers of oxidative stress (glutathione (GSH), malondialdehyde (MDA), reactive oxygen species (ROS)). Molecular biology experiments (qRT-PCR and western blot) were performed to examine AD-related signaling pathways after SYN1 overexpression.

RESULTS

Differential expression analysis yielded a total of 545 differentially expressed genes, of which four were upregulated and 541 were downregulated. The enriched pathways were basically focused on synaptic functions, and the analysis of the protein- protein interaction network focused on the key genes in SYN1. SYN1 significantly improved the spatial learning and memory abilities of AD rats. This enhancement was reflected in the reduced escape latency of the rats in the water maze, the significantly extended dwell time in the third quadrant, and the increased number of crossings. Furthermore, the results of the object recognition test revealed reduced time for rats to explore familiar and new objects. After SYN1 overexpression, the cAMP signaling pathway was activated, the phosphorylation levels of the CREB and PKA proteins were elevated, and the secretion of neurotransmitters such as ACh, DA, and 5-HT was promoted. Furthermore, oxidative stress was suppressed, as supported by decreased levels of MDA and ROS. Regarding inflammatory factors, the levels of IL-6, IL-1β, and TNF-α were significantly reduced in AD rats with SYN1 overexpression.

CONCLUSION

SYN1 overexpression improves cognitive function and promotes the release of various neurotransmitters in AD rats by inhibiting oxidative stress and inflammatory responses through cAMP signaling pathway activation. These findings may provide a theoretical basis for the targeted diagnosis and treatment of AD.

Antimicrobial Peptides with Rigid Linkers against Gram-Negative Bacteria by Targeting Lipopolysaccharide

A series of hybrid peptides were designed by connecting an antimicrobial peptide Ce(1-8) with a lipopolysaccharide (LPS)-targeting peptide Lf(28-34) via different linkers. Antimicrobial experimental results indicated that linkers play an essential role in the anti-Gram-negative bacterial activity of the hybrid peptides. Among these hybrid peptides, peptide CL5 with dipeptide rigid linker LP exhibited excellent activity and selectivity against Gram-negative bacteria. The minimum inhibitory concentrations of CL5 against the tested Gram-negative bacteria were 4-32 μM, while the toxicity toward HEK-293 cells was relatively low. It was found that the interactions of the peptides with LPS were crucial for peptide activity against Gram-negative bacteria. Antimicrobial mechanistic studies showed that peptide CL5 contributed to the death of Gram-negative bacterial cells by disrupting the integrity of the bacterial membranes. This study revealed the importance of linker selection in the design of hybrid peptides and provides the basis for the further development of antimicrobial peptides.

Leptospira infection complicated by demyelinating disease: A case report

Leptospirosis is a zoonotic disease, found worldwide, that is caused by bacteria of the genus Leptospira. People can be infected with Leptospira if they come in direct contact with the urine of an infected animal. Leptospirosis may be associated with demyelinating lesions of the central nervous system. This case report describes a 66-year-old female patient who presented with fever and generalized aches and progressed to unconsciousness within a few hours of admission. Laboratory tests showed Leptospira infection, and brain magnetic resonance imaging revealed acute demyelinating lesions. The patient responded well to penicillin and intravenous methylprednisolone therapy. Leptospirosis presenting with acute disseminated encephalomyelitis is rare. In this patient, an interdisciplinary collaboration involving the neurologist, radiologist, and pathologist was crucial for diagnosis and management. Further studies are warranted to investigate whether there is a correlation between demyelinating lesions and leptospiral infection.

Inhibiting creep in nanograined alloys with stable grain boundary networks

Creep, the time-dependent deformation of materials stressed below the yield strength, is responsible for a great number of component failures at high temperatures. Because grain boundaries (GBs) in materials usually facilitate diffusional processes in creep, eliminating GBs is a primary approach to resisting high-temperature creep in metals, such as in single-crystal superalloy turbo blades. We report a different strategy to inhibiting creep by use of stable GB networks. Plastic deformation triggered structural relaxation of high-density GBs in nanograined single-phased nickel-cobalt-chromium alloys, forming networks of stable GBs interlocked with abundant twin boundaries. The stable GB networks effectively inhibit diffusional creep processes at high temperatures. We obtained an unprecedented creep resistance, with creep rates of ~10 –7 per second under gigapascal stress at 700°C (~61% melting point), outperforming that of conventional superalloys.

SILAC-based chemoproteomics reveals a neoligan analogue as an anti-inflammatory agent targeting IRGM to ameliorate cytokine storm

Cytokine storm is a key feature of sepsis and severe stage of COVID-19, and the immunosuppression after excessive immune activation is a substantial hazard to human life. Both pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) are recognized by various pattern recognition receptors (PRRs), which lead to the immune response. A number of neolignan analogues were synthesized in this work and showed powerful anti-inflammation properties linked to the response to innate and adaptive immunity, as well as NP-7 showed considerable anti-inflammatory activity at 100 nM. On the sepsis model caused by cecum ligation and puncture (CLP) in C57BL/6J mice, NP-7 displayed a strong regulatory influence on cytokine release. Then a photo-affinity probe of NP-7 was synthesized and chemoproteomics based on stable isotope labeling with amino acids in cell cultures (SILAC) identified Immunity-related GTPase M (IRGM) as a target suppressing cytokine storm, which was verified by competitive pull-down, cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS) and molecular dynamics simulations.

Chronic insulin resistance deteriorates cardiac mitochondrial quality control in a mouse model of SEC-NAFLD-IR

Background

Insulin resistance and nonalcoholic fatty liver disease (NAFLD) both relate to cardiovascular mortality. Using a mouse model of chronic lipid overload and secondary-NAFLD-induced insulin resistance (SEC-NAFLD-IR), we recently deciphered that SEC-NAFLD-IR already at young age provoked myocardial lipotoxicity with reduced mitochondrial efficiency and increased vulnerability to cardiac ischemia. However, long-term consequences of SEC-NAFLD-IR remain elusive.

Purpose

Here we aimed to elucidate the impact of long-term SEC-NAFLD-IR on multiple mitochondrial quality control (mQC) mechanisms in the heart and its consequences for cardiac function.

Methods

We studied 36 SEC-NAFLD-IR mice (72-week-old). For mechanistic experiments, we applied palmitate-induced insulin resistant murine HL-1 cells. Cardiac mitochondrial dynamics were measured via quantification of mitochondrial morphology and expression of mitochondrial fusion and fission factors (Opa1, Drp1, Fis1, Mfn 1 & 2). Mitophagy level was evaluated via immunofluorescence and protein expression of key mitophagy-related genes (Parkin, NIX, LC3). Mitochondrial biogenesis and mass were examined via quantitation of PGC-1α expression, mtDNA and citrate synthase activity.

Results

72-week-old SEC-NAFLD-IR mice exhibited 21% (p=0.001) and 32% (p&lt;0.001) higher body weight and heart weight compared with controls. Along with elevated oxidative stress, hepatic lipid accumulation and inflammation, 6h-fasted SEC-NAFLD-IR mice were characterized by increased plasma glucose, insulin and cholesterol. SEC-NAFLD-IR mice displayed a cardiac phenotype with 21% higher left ventricular mass (normalized to body weight, p&lt;0.001) and 6% lower ejection fraction compared to controls (73.5% SEM 0.90 vs 69.4% SEM 1.65, p=0.04). We found several advantageous mQC mechanisms suppressed in aged SEC-NAFLD-IR mice including long form OPA1-mediated mitochondrial fusion, Parkin- and NIX-mediated mitophagy. Likewise, mitochondrial biogenesis was suppressed in the aged insulin-resistant heart, which was connected to a 65% downregulation of PGC-1α1 expression (p=0.01). Interestingly, downregulation of cardiac PGC-1α1 in aged SEC-NAFLD-IR mice coincided with upregulation of PARIS, indicating the crucial participation of the Parkin/PARIS pathway in mQC of the insulin-resistant heart. In addition, induction of insulin resistance in murine HL-1 cardiomyocytes also led to increased mitochondrial fragmentation and decreased PGC-1α1 expression.

Conclusion

This study demonstrated that regulation of mitochondrial network and turnover is hampered by SEC-NAFLD-IR in the hearts of aged mice, which may contribute to hypertrophy and cardiac dysfunction in insulin resistance.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Collaborative Research Centre 1116 (German Research Foundation)

YAFAF-Based Hydrogel: Characterization, Mechanism, and Factors Influencing Micro-organization

The YAFAF-based hydrogel was a three-dimensional network cross-linked by grooved fiber bundles. The fiber bundles were formed by entanglement of fibrils with a diameter of 2 nm, and the surface of the fibrils also presented grooves. Spectroscopic analysis revealed that the main secondary structures were β-sheets and β-turns, which led to the grooved feature of fibrils. In comparison of the nuclear magnetic resonance spectra of peptide solutions at 313 and 277 K, the nuclear Overhauser effects can be clearly observed, indicating that hydrogen-bondings and π-π stacking interactions play important roles in self-assembly. The micro-organization of the self-assemblies was affected by the ratio of solvents (x_A) remarkably. Unexpectedly, x_A of 0.05 produced hollow spherical aggregates. The result of these investigations on the mechanism and organization of the YAFAF-based hydrogel can contribute to the development of strategies using hydrogels in the food industry.