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Naringenin inhibits ferroptosis to reduce radiation-induced lung injury: insights from network Pharmacology and molecular docking

CONTEXT

Naringenin is a natural flavanone with potent pharmacological properties. It has demonstrated therapeutic potential in treating various diseases and organ injuries, including radiation-induced lung injury (RILI). Ferroptosis is a newly type of cell death, and naringenin has been shown to attenuates ferroptosis.

OBJECTIVE

To evaluate the inhibitory effect and molecular mechanism of naringenin on ferroptosis during RILI process.

MATERIALS & METHODS

Firstly, BEAS-2B and HUVECs cells were pre-incubated with naringenin for 1 h prior to 8 Gy of X-ray irradiation to evaluate oxidative stress, inflammation, and the mRNA levels of ferroptosis-related genes. Next, target genes of naringenin, RILI, and ferroptosis were identified using the TCMSP, SwissTargetPrediction, and GeneCards databases. The target network was constructed with Cytoscape and STRING. Finally, the core target genes were identified through in vitro experiments by qRT-PCR, western blot and immunofluorescence staining.

RESULTS

Naringenin effectively reduced radiation-induced increasement of oxidative stress, inflammation, and ferroptosis markers in both cell lines. Network pharmacology identified 14 target genes, with prostaglandin endoperoxide synthase (PTGS2) and Valosin-containing protein (VCP) mRNA levels being prominent, which were crucial for ferroptosis regulation. Molecular docking revealed strong binding interactions between naringenin and the two target proteins. Subsequently, experimental validation confirmed that naringenin reduced the elevated levels of PTGS2 and VCP induced by radiation.

DISCUSSION & CONCLUSION

Naringenin alleviates radiation-induced lung damage by inhibiting ferroptosis, with PTGS2 and VCP emerging as potential therapeutic targets.

Construction of a variable fragment (Fv)-immunoglobulin A (IgA) anti-receptor binding domain (RBD) SARS-CoV-2 library based on IgA from Indonesian COVID-19 survivors

Despite entering the post-pandemic phase, SARS-CoV-2 remains a treatment challenge due to evolving mutations and immune evasion, leading to the emergence of antibody-resistant variants. This study aims to computationally construct a human Fv against various emerged variants of SARS-CoV-2 based on IgA sequences from Indonesian COVID-19 survivors. Survivor's saliva and plasma were purified using affinity chromatography to isolate anti-SARS-CoV-2 IgA. The IgA components, heavy and light chains, were isolated using SDS-PAGE and confirmed by Western Blot. They were extracted, digested with trypsin and chymotrypsin, and sequenced using LC MS/MS. Full Fvs were constructed based on IgA sequence obtained and covered with database and reference sequences to generate an Fv Library. The selection of the Fv Library was performed based on modelling, developability, and molecular docking analysis against various RBD variants. The study identified 9 potential Fvs with strong binding affinities to RBD-SARS-CoV-2 across all variants with RMSD values of CDR and Framework of Fv model structures <0.5 Å and developability scores within the safe therapeutic range. FVIGA0289, one of the top candidates, had binding affinities (ΔG) of -17.5, -16.3, -15.6, -16.6, -17.4, and -17.6 kcal/mol for the Wuhan, alpha, beta, gamma, delta, and omicron (XBB.1.5) variants, respectively. In conclusion, the use of antibody information isolated from Indonesian patients has successfully facilitated the computational construction of IgA-based Fv candidates with strong binding to multiple SARS-CoV-2 variants, supported by promising structural models and developability.

MuGger Toxins: Exploring the Selective Binding Mechanism of Clostridial Glucosyltransferase Toxin B and Host GTPases

(a) Clostridioides difficile ( C. difficile ) bacterium can cause severe diarrhea and its over-colonization in the host's intestinal tract lead to the development of pseudomembranous colitis, generally due to antibiotic usage. The primary exotoxins involved are toxin A (TcdA) and toxin B (TcdB), the latter being more pathogenic. TcdB has glucosyltransferase activity and mediates monoglycosylation by targeting host cell enzymes (mainly Rho and Ras family of GTPases) with differential selectivity. Here, we aim to provide structural and dynamic insights into how TcdB impacts the host's intestinal epithelial cells focusing on the glycosylation mechanism of Rho GTPases, Cdc42, and Rac1, at the molecular level. To this aim, we modeled the unknown TcdB-host protein complex structures, based on the available experimental structures of TcdB, through protein-protein docking. Then, we elaborated on TcdB-Rho GTPase models as TcdB is known to selectively interact with GDP-bound inactive states of Rho GTPases, over the GTP-bound active ones, but the mechanism is unclear. Through a total of 6 μs-long molecular dynamics simulation of TcdB and GTP/GDP-bound Rac1 and Cdc42 complexes, TcdB's selective binding mechanism was revealed for Rac1. TcdB-Rac1 complexes were further analyzed with enhanced sampling techniques such as well-tempered metadynamics simulations and umbrella sampling to reveal selective binding mechanism between TcdB and GDP-bound Rac1. Our results show that TcdB selectively binds to GDP-bound Rac1, over the GTP-bound one, driven by its affinity for the Mg2+ ion. A destabilized Mg2+ ion incapable of coordinating GDP disrupts Rac1's GTPase function, shedding light on the molecular basis of TcdB's pathogenic effects.

Identification and characterisation of a novel interaction between oestrogen receptor alpha and FOXP2

Forkhead box P2 (FOXP2) regulates expression of various genes and is associated with language, speech and neural development as well as cancer. Since there may be a putative link between sex and language and because transcription factors rarely function in isolation, this study aims to investigate whether FOXP2 directly associates with oestrogen receptor α (ER1), a nuclear receptor responsible for sexual differentiation that is also associated with cancer. Isothermal titration calorimetry and fluorescence anisotropy were used to investigate the interaction between the DNA-binding forkhead domain (FHD) of FOXP2, the N-terminal region (NT) of FOXP2, and the ligand-binding domain (LBD) of ER1. ER1 LBD does not interact with FOXP2 NT but associates with apo-FOXP2 FHD in an enthalpically favourable manner. The affinity of this interaction is inversely correlated to the salt concentration. Additionally, FOXP2 FHD that is bound to ER1 LBD, has reduced ability to interact with its cognate DNA. This research identifies a novel interaction between ER1 LBD and FOXP2 FHD and shows that the interaction is regulated by salt. Moreover, FOXP2 FHD cannot bind to both ER1 LBD and DNA simultaneously, suggesting that this interaction could be involved in regulating the transcriptional pathway of FOXP2 should the interaction be found in vivo. This study could serve as a foundation for uncovering the basis of sexual dimorphism in speech and language development and related disorders and potentially offers an alternate for targeted cancer therapies.

Conformational dynamics of adenylate kinase in crystals

Adenylate kinase is a ubiquitous enzyme in living systems and undergoes dramatic conformational changes during its catalytic cycle. For these reasons, it is widely studied by genetic, biochemical, and biophysical methods, both experimental and theoretical. We have determined the basic crystal structures of three differently liganded states of adenylate kinase from Methanotorrus igneus, a hyperthermophilic organism whose adenylate kinase is a homotrimeric oligomer. The multiple copies of each protomer in the asymmetric unit of the crystal provide a unique opportunity to study the variation in the structure and were further analyzed using advanced crystallographic refinement methods and analysis tools to reveal conformational heterogeneity and, thus, implied dynamic behaviors in the catalytic cycle.

Multi-target mechanism of Solanum xanthocarpum for treatment of psoriasis based on network pharmacology and molecular docking

Solanum xanthocarpum (SX) has been used to treat a variety of diseases, including skin disorders like psoriasis (PSO). SX possesses many pharmacological activities of anti-inflammatory, anti-cancer, immunosuppressive, and healing qualities. However, the multi-target mechanism of SX on PSO still needs clarity. Materials and methods: The Indian Medicinal Plants, Phytochemicals and Therapeutics (IMPPAT) database and the Swiss Target Prediction online tool were used to find the active phytochemical components and their associated target proteins. OMIM and GeneCards databases were used to extract PSO-related targets. A Venn diagram analysis determined the common targets of SX against PSO. Subsequently, the protein-protein interaction (PPI) network and core PPI target analysis were carried out using the STRING network and Cytoscape software. Also, utilising the online Metascape and bioinformatics platform tool, a pathway enrichment analysis of common targets using the Kyoto Encyclopaedia of Genes and Genome (KEGG) and Gene Ontology (GO) databases was conducted to verify the role of targets in biological processes, cellular components and molecular functions with respect to KEGG pathways. Lastly, molecular docking simulations were performed to validate the strong affinity between components of SX and key target receptors. Results: According to the IMPPAT Database information, 8 active SX against PSO components were active. According to the PPI network and core targets study, the main targets against PSO were EGFR, SRC, STAT3, ERBB2, PTK2, SYK, EP300, CBL, TP53, and AR. Moreover, molecular docking simulations verified the binding interaction of phytochemical SX components with their PSO targets. Last but not least, enrichment analysis showed that SX is involved in several biological processes, including peptidyl-tyrosine phosphorylation, peptidyl-tyrosine modification, and peptidyl-serine modification. The relevant KEGG signalling pathways are the PI3K-AKT signalling pathway, the EGFR tyrosine kinase inhibitor resistance pathway, and the MAPK signalling pathway. Conclusion: The network pharmacology technique, which is based on data interpretation and molecular docking simulation techniques, has proven the multi-target function of SX phytoconstituents.

Improving the quality of co-evolution intermolecular contact prediction with DisVis

The steep rise in protein sequences and structures has paved the way for bioinformatics approaches to predict residue-residue interactions in protein complexes. Multiple sequence alignments are commonly used in contact predictions to identify co-evolving residues. These contacts, however, often include false positives (FPs), which may impair their use to predict three dimensional structures of biomolecular complexes and affect the accuracy of the generated models. Previously, we have developed DisVis to identify FP in mass spectrometry cross-linking data. DisVis allows to assess the accessible interaction space between two proteins consistent with a set of distance restraints. Here, we investigate if a similar approach could be applied to co-evolution predicted contacts in order to improve their precision prior to using them for modeling. We analyze co-evolution contact predictions with DisVis for a set of 26 protein-protein complexes. The DisVis-reranked and the original co-evolution contacts are then used to model the complexes with our integrative docking software HADDOCK using different filtering scenarios. Our results show that HADDOCK is robust with respect to the precision of the predicted contacts due to the 50% random contact removal during docking and can enhance the quality of docking predictions when combined with DisVis filtering for low precision contact data. DisVis can thus have a beneficial effect on low quality data, but overall HADDOCK can accommodate FP restraints without negatively impacting the quality of the resulting models. Other more precision-sensitive docking protocols might, however, benefit from the increased precision of the predicted contacts after DisVis filtering.

Site-Specific Activity-Based Protein Profiling Using Phosphonate Handles

Most drug molecules target proteins. Identification of the exact drug binding sites on these proteins is essential to understand and predict how drugs affect protein structure and function. To address this challenge, we developed a strategy that uses immobilized metal-affinity chromatography-enrichable phosphonate affinity tags, for efficient and selective enrichment of peptides bound to an activity-based probe, enabling the identification of the exact drug binding site. As a proof of concept, using this approach, termed PhosID-ABPP (activity-based protein profiling), over 500 unique binding sites were reproducibly identified of an alkynylated afatinib derivative (PF-06672131). As PhosID-ABPP is compatible with intact cell inhibitor treatment, we investigated the quantitative differences in approachable binding sites in intact cells and in lysates of the same cell line and observed and quantified substantial differences. Moreover, an alternative protease digestion approach was used to capture the previously reported binding site on the epidermal growth factor receptor, which turned out to remain elusive when using solely trypsin as protease. Overall, we find that PhosID-ABPP is highly complementary to biotin-based enrichment strategies in ABPP studies, with PhosID-ABPP providing the advantage of direct activity-based probe interaction site identification.

Integrated plasma pharmacochemistry and network pharmacology to explore the mechanism of Gerberae Piloselloidis Herba in treatment of allergic asthma

ETHNOPHARMACOLOGICAL RELEVANCE

Gerberae Piloselloidis Herba (GPH), a commonly used traditional medicine in China, is derived from Gerbera piloselloides (Linn.) Cass. It is featured by its special bioactivities as antitussive, expectorant, anti-asthma, anti-bacterial, anti-tumor, uterine analgesia, and immunity-enhancing. With a long history of medication in ethnic minority areas in China, it is often used as an effective treatment for cough and sore throat as well as allergic asthma. Although our previous investigation also has discovered GPH performed effective treatment on allergic asthma, its underlying mechanism remains unclear.

AIM OF THE STUDY

This research aims to reveal the pharmacological mechanism of GPH in the treatment for allergic asthma through combination of plasma pharmacology and network pharmacology.

MATERIALS AND METHODS

Firstly, the components of GPH in blood samples were identified using UHPLC- Q-Orbitrap HRMS. An interaction network of "compound-target-disease" was constructed based on the compounds confirmed in blood and on their corresponding targets of allergic asthma acquired from disease gene databases, predicting the possible biological targets and potential signal pathways of GPH with the network pharmacology analysis. Then, a molecular docking between the blood ingredients and the core targets was carried out using the Autodock Vina software. Subsequently, after establishing a mouse model with allergic asthma induced by ovalbumin (OVA), the effect of GPH on allergic asthma was evaluated by analyzing a series of indicators including behavior, lung pathological changes, inflammatory factors in serum and bronchoalveolar lavage fluid (BALF). Finally, the key pathway and targets predicted by network pharmacology and molecular docking were further verified using Western blot analysis.

RESULTS

Eleven chemical constituents (such as arbutin, neochlorogenic acid, chlorogenic acid, etc.) were identified through the analysis of plasma samples, on which basis a total of 142 genes intersecting GPH and allergic asthma were collected by network pharmacology. After performing enrichment analysis of these genes in gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG), it was found that arbutin-related targets mainly focused on phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) signal pathway, while luteolin and marmesin -related targets tended to locate at Interleukin-17 (IL-17) signal pathway. Meanwhile, the findings of molecular docking suggested that such components as arbutin, luteolin and marmesin entering into blood had good binding with the core targets related to PI3K/Akt and IL-17 pathways. In addition, GPH improved the OVA-induced asthma symptoms, the alveolar septa thickening and the infiltration of inflammatory cell around bronchi and bronchioles as well as reduced the levels of IgE, IL-8 and TNF-α in serum or BALF. Furthermore, GPH could inhibit the phosphorylation level of Akt and the expression of PI3K, an efficacy supported by the findings by way of Western blot which suggests that GPH in the treatment of allergic asthma was linked to PI3K/Akt signal pathway.

CONCLUSION

In this study, a comprehensive strategy to combine the UPLC-Q-Orbitrap HRMS with network pharmacology was employed to clarify the mechanism of GPH against allergic asthma, a finding where GPH may inhibit PI3K/Akt signal pathway to protect mice from OVA-induced allergic asthma. This study provides a deeper understanding of the pharmacological mechanism of GPH in treatment of asthma, offering a scientific reference for further research and clinical application of GPH in terms of allergic asthma.

An integrative pan-cancer analysis revealing the difference in small ring finger family of SCF E3 ubiquitin ligases

Background

The SCF (Skp1-cullin-F-box proteins) complex is the largest family of E3 ubiquitin ligases that mediate multiple specific substrate proteins degradation. Two ring-finger family members RBX1/ROC1 and RBX2/RNF7/SAG are small molecular proteins necessary for ubiquitin ligation activity of the multimeric SCF complex. Accumulating evidence indicated the involvement of RBX proteins in the pathogenesis and development of cancers, but no research using pan-cancer analysis for evaluating their difference has been directed previously.

Methods

We investigated RBX1/2 expression patterns and the association with clinicopathological features, and survivals of cancer patients obtained from the TCGA pan-cancer data. The binding energies of RBX1/2-CUL1 complexes were preliminarily calculated by using molecular dynamics simulations. Meanwhile, we assessed their immune infiltration level across numerous databases, including TISIDB and Timer database.

Results

High expression levels of RBX1/2 were observed in most cancer types and correlated with poor prognosis of patients analyzed. Nonetheless, exceptions were observed: RBX2 expression in KICH was higher than normal renal tissues and played a detrimental role in KICH. The expression of RBX1 was not associated with the prognostic risk of KICH. Moreover, the combination of RBX1 and CUL1 expression is more stable than that of RBX2 and CUL1. RBX1/2 expression showed their own specific characteristics in tumor pathological stages and grades, copy number variation and immune components.

Conclusions

These findings not only indicated that the difference of RBX1/2 might result in varying degrees of tumor progression, but also suggested that they might serve as biomarkers for immune infiltration in cancers, shedding new light on therapeutics of cancers.

Binding of 30S Ribosome Induces Single-stranded Conformation Within and Downstream of the Expression Platform in a Translational Riboswitch

Translational riboswitches are bacterial gene regulatory elements found in the 5'-untranslated region of mRNAs. They operate through a conformational refolding reaction that is triggered by a concentration change of a modulating small molecular ligand. The translation initiation region (TIR) is either released from or incorporated into base pairing interactions through the conformational switch. Hence, initiation of translation is regulated by the accessibility of the Shine-Dalgarno sequence and start codon. Interaction with the 30S ribosome is indispensable for the structural switch between functional OFF and ON states. However, on a molecular level it is still not fully resolved how the ribosome is accommodated near or at the translation initiation region in the context of translational riboswitches. The standby model of translation initiation postulates a binding site where the mRNA enters the ribosome and where it resides until the initiation site becomes unstructured and accessible. We here investigated the adenine-sensing riboswitch from Vibrio vulnificus. By application of a ¹⁹F labelling strategy for NMR spectroscopy that utilizes ligation techniques to synthesize differentially ¹⁹F labelled riboswitch molecules we show that nucleotides directly downstream of the riboswitch domain are first involved in productive interaction with the 30S ribosomal subunit. Upon the concerted action of ligand and the ribosomal protein rS1 the TIR becomes available and subsequently the 30S ribosome can slide towards the TIR. It will be interesting to see whether this is a general feature in translational riboswitches or if riboswitches exist where this region is structured and represent yet another layer of regulation.

Structural Biology in the Clouds: The WeNMR-EOSC Ecosystem

Structural biology aims at characterizing the structural and dynamic properties of biological macromolecules at atomic details. Gaining insight into three dimensional structures of biomolecules and their interactions is critical for understanding the vast majority of cellular processes, with direct applications in health and food sciences. Since 2010, the WeNMR project (www.wenmr.eu) has implemented numerous web-based services to facilitate the use of advanced computational tools by researchers in the field, using the high throughput computing infrastructure provided by EGI. These services have been further developed in subsequent initiatives under H2020 projects and are now operating as Thematic Services in the European Open Science Cloud portal (www.eosc-portal.eu), sending >12 millions of jobs and using around 4,000 CPU-years per year. Here we review 10 years of successful e-infrastructure solutions serving a large worldwide community of over 23,000 users to date, providing them with user-friendly, web-based solutions that run complex workflows in structural biology. The current set of active WeNMR portals are described, together with the complex backend machinery that allows distributed computing resources to be harvested efficiently.

PDB-tools web: A user-friendly interface for the manipulation of PDB files

The Protein Data Bank (PDB) file format remains a popular format used and supported by many software to represent coordinates of macromolecular structures. It however suffers from drawbacks such as error‐prone manual editing. Because of that, various software toolkits have been developed to facilitate its editing and manipulation, but, to date, there is no online tool available for this purpose. Here we present PDB‐Tools Web, a flexible online service for manipulating PDB files. It offers a rich and user‐friendly graphical user interface that allows users to mix‐and‐match more than 40 individual tools from the pdb‐tools suite. Those can be combined in a few clicks to perform complex pipelines, which can be saved and uploaded. The resulting processed PDB files can be visualized online and downloaded. The web server is freely available at https://wenmr.science.uu.nl/pdbtools.