Discovery of a novel class of rosmarinic acid derivatives as antibacterial agents: Synthesis, structure-activity relationship and mechanism of action.

Twenty-seven rosmarinic acid derivatives were synthesized, among which compound RA-N8 exhibited the most potent antibacterial ability. The minimum inhibition concentration of RA-N8 against both S. aureus (ATCC 29213) and MRSA (ATCC BAA41 and ATCC 43300) was found to be 6 µg/mL, and RA-N8 killed E. coli (ATCC 25922) at 3 µg/mL in the presence of polymyxin B nonapeptide (PMBN) which increased the permeability of E. coli. RA-N8 exhibited a weak hemolytic effect at the minimum inhibitory concentration. SYTOX Green assay, SEM, and LIVE/DEAD fluorescence staining assay proved that the mode of action of RA-N8 is targeting bacterial cell membranes. Furthermore, no resistance in wildtype S. aureus developed after incubation with RA-N8 for 20 passages. Cytotoxicity studies further demonstrated that RA-N8 is non-toxic to the human normal cell line (HFF1). RA-N8 also exerted potent inhibitory ability against biofilm formation of S. aureus and even collapsed the shaped biofilm.

A taxonomic study on the nominate subgenus Macrolycus Waterhouse, 1878 from China (Coleoptera, Lycidae).

In the present study, a new species of Macrolycus s. str. is reported from China and described as M. subapicis sp. nov. M. bowringi Waterhouse, 1878 is recorded to China for the first time. The above two species, M. oreophilus Kazantsev, 2002 and M. gansuensis Kazantsev, 2002 are illustrated with the male habitus and genitalia. In addition, a distribution map, and a key to the species of Macrolycus s. str. in the world are provided.

Identification of genetic features that are associated with amplitude of low-frequency fluctuation changes in schizophrenia using omics analysis.

Genetic risk for schizophrenia is thought to trigger variation in clinical features of schizophrenia, but biological processes associated with neuronal activity in brain regions remain elusive. In this study, gene expression features were mapped to various sub-regions of the brain by integrating low-frequency amplitude features and gene expression data from the schizophrenia brain and using gene co-expression network analysis of the Allen Transcriptome Atlas of the human brain from six donors to identify genetic features of brain regions and important associations with neuronal features. The results indicate that changes in the dynamic amplitude of low-frequency fluctuation (dALFF) are mainly associated with transcriptome signature factors such as cortical layer synthesis, immune response, and expanded membrane transport. Further modular disease enrichment analysis revealed that the same set of signature genes associated with dALFF levels was enriched for multiple neurological biological processes. Finally, genetic profiling of individual modules identified multiple core genes closely related to schizophrenia, also potentially associated with neuronal activity. Thus, this paper explores genetic features of brain regions in the schizophrenia closely related to low-frequency amplitude ratio levels based on imaging genetics, which suggests structural endophenotypes associated with schizophrenia.

Transplantation of human placental chorionic plate-derived mesenchymal stem cells for repair of neurological damage in neonatal hypoxic-ischemic encephalopathy.

JOURNAL/nrgr/04.03/01300535-202409000-00035/figure1/v/2024-01-16T170235Z/r/image-tiff Neonatal hypoxic-ischemic encephalopathy is often associated with permanent cerebral palsy, neurosensory impairments, and cognitive deficits, and there is no effective treatment for complications related to hypoxic-ischemic encephalopathy. The therapeutic potential of human placental chorionic plate-derived mesenchymal stem cells for various diseases has been explored. However, the potential use of human placental chorionic plate-derived mesenchymal stem cells for the treatment of neonatal hypoxic-ischemic encephalopathy has not yet been investigated. In this study, we injected human placental chorionic plate-derived mesenchymal stem cells into the lateral ventricle of a neonatal hypoxic-ischemic encephalopathy rat model and observed significant improvements in both cognitive and motor function. Protein chip analysis showed that interleukin-3 expression was significantly elevated in neonatal hypoxic-ischemic encephalopathy model rats. Following transplantation of human placental chorionic plate-derived mesenchymal stem cells, interleukin-3 expression was downregulated. To further investigate the role of interleukin-3 in neonatal hypoxic-ischemic encephalopathy, we established an in vitro SH-SY5Y cell model of hypoxic-ischemic injury through oxygen-glucose deprivation and silenced interleukin-3 expression using small interfering RNA. We found that the activity and proliferation of SH-SY5Y cells subjected to oxygen-glucose deprivation were further suppressed by interleukin-3 knockdown. Furthermore, interleukin-3 knockout exacerbated neuronal damage and cognitive and motor function impairment in rat models of hypoxic-ischemic encephalopathy. The findings suggest that transplantation of hpcMSCs ameliorated behavioral impairments in a rat model of hypoxic-ischemic encephalopathy, and this effect was mediated by interleukin-3-dependent neurological function.

Unexpected High Species Diversity of Mesolycus Gorham (Coleoptera, Lycidae) from China, with a Preliminary Investigation on Its Phylogenetic Position Based on Multiple Genes.

The lycid genus Mesolycus Gorham, 1883 is mainly distributed in East Palaearctic and Indochinese regions, but poorly studied in China; moreover, its phylogenetic placement remains controversial but has never been rigorously tested. In this study, Mesolycus was reviewed and its placement within Lycidae was tested based on a multilocus phylogeny (cox1, nad5, cox2 and Lrna) by both ML and BI analyses. The reconstructed phylogenies show that Mesolycus is a consistently recovered sister to Dilophotes Waterhouse, 1879, and they form a monophyletic clade which is well supported. This suggests that Mesolycus definitely belongs to Dilophotini rather than to Macrolycini of Lycinae. Besides, three species originally described or placed in Dilophotes are transferred to Mesolycus, including M. atricollis (Pic, 1926) comb. n., M. particularis (Pic, 1928) comb. n. and M. pacholatkoi (Bic, 2002) comb. n. Four new species are discovered in China, including M. shaanxiensis sp. n., M. dentatus sp. n., M. breviplatus sp. n. and M. varus sp. n. Two species, M. murzini Kazantsev, 2004 and M. rubromarginatus Kazantsev, 2013, are recorded from China for the first time. A key for the identification of all Mesolycus species is provided. China was revealed as the region with the highest species diversity of this genus.

Rational design and structural engineering of heterogeneous single-atom nanozyme for biosensing.

Nanozymes, an emerging family of heterogeneous nanomaterials with enzyme-like characteristics, offer significant advantages as alternatives to natural enzymes for diverse biocatalytic applications. Nevertheless, the inhomogeneous configuration of nanomaterials makes it extremely challenging to develop nanozymes of desired performance and reaction mechanism. Single-atom nanozymes (SAzymes) that are composed of single-atomic active sites may provide an answer to these challenges with remarkable enzyme-like activity and specificity. The well-defined coordination microenvironments of SAzymes offer a suitable model system to investigate the structure-activity relationship and thus bridge the gap between natural enzyme and nanozyme. In this review, we would first present an overview of discoveries, advantages, and classifications of SAzymes. Then, we would discuss the reaction mechanism, design principles, and biosensing applications of a series of typical SAzymes with a focus on the rational design strategies for targeted reaction and the effort to uncover the catalytic mechanism at the atomic scale. Finally, we would provide the challenges and future perspectives of SAzymes as the next-generation nanozymes.

The age-specific pathological changes of ß-amyloid plaques in the cortex and hippocampus of APP/PS1 transgenic AD mice.

OBJECTIVE: Numerous pathological variations and complex interactions are involved in the long period prior to cognitive decline in brains with Alzheimer's disease (AD). Thus, elucidation of the pathological disorders can facilitate early AD diagnosis. The aim of this study was to investigate the age-specific pathological changes of ß-amyloid plaques in brain tissues of AD mice at different ages. METHODS: We arranged the most widely available APP/PS1 transgenic AD models into six age groups: 3, 4 and 6 months (these three groups mimicked early-clinical stage AD), 9, 12 and 15 months (these three groups mimicked late-clinical stage AD). Cell morphology and arrangement in the cortex and hippocampus were observed by hematoxylin and eosin (HE) staining. Congo red staining and immunohistochemical staining were performed to exhibit the distribution of ß-amyloid plaques in the cortex and hippocampus of AD brains. RESULTS: Our results found that as age increased, the nuclei of cortical and hippocampal cells in AD mice were severely damaged. The number and area of ß-amyloid plaques increased in AD mice in correspondence with age revealed by histological experiments. Importantly, ß-amyloid plaques were detected in the cortex and hippocampus of 6-month-old AD mice shown by Congo red staining while detected in the cortex and hippocampus of 4-month-old AD mice shown by immunohistochemical staining. CONCLUSIONS: The current study revealed the age-related pathological changes of ß-amyloid plaques in the cortex and hippocampus of AD mice and displayed a higher specificity of immunohistochemical staining than Congo red staining when detecting pathological changes of brain tissues.

NDM-1 Zn1-binding residue His116 plays critical roles in antibiotic hydrolysis.

Bacteria expressing NDM-1 have been labeled as superbugs because it confers upon them resistance to a broad range of ß-lactam antibiotics. The enzyme has a di­zinc active centre, with the Zn2 site extensively studied. The roles of active-site Zn1 ligand residues are, however, still not fully understood. We carried out structure-function studies using the mutants, H116A, H116N, and H116Q. Zinc content analysis showed that Zn1 binding was weakened by 40 to 60% in the H116 mutants. The enzymatic-activity studies showed that the lower hydrolysis rates were mainly caused by their weaker substrate binding. The catalytic efficiency (kcat/Km) of the mutants followed the order: WT > > H116Q (decreased by 4-20 fold) > H116A (decreased by 20-700 fold) ≥ H116N (decreased by 6-800 fold). The maximum effect was observed on H116N against penicillin G, whereas ampicillin was not hydrolyzed at all. The fold-increase of Km values, which informs the weakening of substrate binding, were: H116A by 5-45 fold; H116N by 6-100 fold; H116Q by 2-10 fold. Molecular dynamics simulations suggested that the Zn1 site mutations affected the positions of Zn2 and the bridging hydroxide, by 0.8 to 1.2 Å, with the largest changes of ~1.5 Å observed on Zn2 ligand C221. A native hydrogen bond between H118 and D236 was disrupted in the H116N and H116Q mutants, which led to increased flexibility of loop 10. Consequently, residue N233 was no longer maintained at an optimal position for substrate binding. H116 connected loop 7 across Zn1 to loop 10, thereby contributed to the overall integrity. This work revealed that the H116-Zn1 interaction plays a critical role in defining the substrate-binding site. From these results, it can be inferred that inhibition strategies targeting the zinc ions may be a new direction for drug development.

Corrigendum: MicroRNA339 Targeting PDXK Improves Motor Dysfunction and Promotes Neurite Growth in the Remote Cortex Subjected to Spinal Cord Transection.

[This corrects the article DOI: 10.3389/fcell.2020.00577.].

Corrigendum: Vi4-miR-185-5p-Igfbp3 Network Protects the Brain From Neonatal Hypoxic Ischemic Injury via Promoting Neuron Survival and Suppressing the Cell Apoptosis.

[This corrects the article DOI: 10.3389/fcell.2020.529544.].

Discovery of FtsZ inhibitors by virtual screening as antibacterial agents and study of the inhibition mechanism.

Inhibition of bacterial cell division is a novel mechanistic action in the development of new antimicrobial agents. The FtsZ protein is an important antimicrobial drug target because of its essential role in bacterial cell division. In the present study, potential inhibitors of FtsZ were identified by virtual screening followed by in vivo and in vitro bioassays. One of the candidates, Dacomitinib (S2727), shows for the first time its potent inhibitory activity against the MRSA strains. The binding mode of Dacomitinib in FtsZ was analyzed by docking, and Asp199 and Thr265 are thought to be essential residues involved in the interactions.

Differences between cultured cortical neurons by trypsin and papain digestion.

The objective of this study was to compare the efficiency of trypsin and papain in neuronal digestion and determine which enzyme is more efficient. Cortical tissues were obtained from Sprague-Dawley (SD) rats. According to the different digestive enzymes, the samples were divided into the trypsin group and the papain group. After being digested by each of the two enzymes, cortical neurons were collected from the samples. Then, the morphology of the cortical neurons was determined. Moreover, the cortical neurons were transfected with the negative control (NC) lentivirus. The transfection efficiency and morphology were determined and compared. Compared with the papain group, cortical neurons in the trypsin group were more in number, had larger cell size, had longer axonal length, and had fewer impurities. The transfection efficiency of the trypsin group (57.77%) was higher than that of the papain group (53.83%). The morphology of neurons that was displayed showed that the cell body of most neurons shrank and became smaller, and the axis mutation became shorter and less in the papain group 6 days after transfection with the NC lentivirus. Trypsin is more efficient in digesting neurons because the neurons digested by this enzyme are more in number, have a larger cell body, longer axons, and greater transfection efficiency.

The differentially expressed proteins related to clinical viral encephalitis revealed by proteomics.

To screen out the prospective biomarkers of viral encephalitis (VE), analyze the biological process and signaling pathways involved by differentially expressed proteins (DEPs). A total of 11 cerebrospinal fluid (CSF) samples with VE and 5 with non-nervous system infection were used to perform label-free proteomic techniques. Then, the bioinformatic analysis of DEPs was applied by Interproscan software. Moreover, 73 CSF samples in the VE group and 53 in the control group were used to verify the changes of some DEPs by enzyme-linked immunosorbent assay (ELISA). Thirty-nine DEPs were identified, including 18 upregulated DEPs and 21 downregulated DEPs. DEPs were mainly enriched in cell adhesion molecules by Kyoto Encyclopedia of Genes and Genomes analysis pathway analysis. The DEPs related to axon tissue were obviously downregulated and the most significant downregulated proteins were neurexin 3, neurofascin, and neuroligin 2 (NLGN2). Moreover, the protein expression of NLGN2 in the VE group was significantly higher than that in the control group by ELISA. The correlation analysis of NLGN2 in the VE group revealed that there was a weak positive correlation with CSF protein and a weak negative correlation with CSF chloride. The clinical VE may be closely related to NLGN2 and the cell adhesion molecule pathway.

Gossypol acetate: A natural polyphenol derivative with antimicrobial activities against the essential cell division protein FtsZ.

Antimicrobial resistance has attracted worldwide attention and remains an urgent issue to resolve. Discovery of novel compounds is regarded as one way to circumvent the development of resistance and increase the available treatment options. Gossypol is a natural polyphenolic aldehyde, and it has attracted increasing attention as a possible antibacterial drug. In this paper, we studied the antimicrobial properties (minimum inhibitory concentrations) of gossypol acetate against both Gram-positive and Gram-negative bacteria strains and dig up targets of gossypol acetate using in vitro assays, including studying its effects on functions (GTPase activity and polymerization) of Filamenting temperature sensitive mutant Z (FtsZ) and its interactions with FtsZ using isothermal titration calorimetry (ITC), and in vivo assays, including visualization of cell morphologies and proteins localizations using a microscope. Lastly, Bacterial membrane permeability changes were studied, and the cytotoxicity of gossypol acetate was determined. We also estimated the interactions of gossypol acetate with the promising target. We found that gossypol acetate can inhibit the growth of Gram-positive bacteria such as the model organism Bacillus subtilis and the pathogen Staphylococcus aureus [both methicillin-sensitive (MSSA) and methicillin-resistant (MRSA)]. In addition, gossypol acetate can also inhibit the growth of Gram-negative bacteria when the outer membrane is permeabilized by Polymyxin B nonapeptide (PMBN). Using a cell biological approach, we show that gossypol acetate affects cell division in bacteria by interfering with the assembly of the cell division FtsZ ring. Biochemical analysis shows that the GTPase activity of FtsZ was inhibited and polymerization of FtsZ was enhanced in vitro, consistent with the block to cell division in the bacteria tested. The binding mode of gossypol acetate in FtsZ was modeled using molecular docking and provides an understanding of the compound mode of action. The results point to gossypol (S2303) as a promising antimicrobial compound that inhibits cell division by affecting FtsZ polymerization and has potential to be developed into an effective antimicrobial drug by chemical modification to minimize its cytotoxic effects in eukaryotic cells that were identified in this work.

Single-cell RNA sequencing reveals B cell-related molecular biomarkers for Alzheimer's disease.

In recent years, biomarkers have been integrated into the diagnostic process and have become increasingly indispensable for obtaining knowledge of the neurodegenerative processes in Alzheimer's disease (AD). Peripheral blood mononuclear cells (PBMCs) in human blood have been reported to participate in a variety of neurodegenerative activities. Here, a single-cell RNA sequencing analysis of PBMCs from 4 AD patients (2 in the early stage, 2 in the late stage) and 2 normal controls was performed to explore the differential cell subpopulations in PBMCs of AD patients. A significant decrease in B cells was detected in the blood of AD patients. Furthermore, we further examined PBMCs from 43 AD patients and 41 normal subjects by fluorescence activated cell sorting (FACS), and combined with correlation analysis, we found that the reduction in B cells was closely correlated with the patients' Clinical Dementia Rating (CDR) scores. To confirm the role of B cells in AD progression, functional experiments were performed in early-stage AD mice in which fibrous plaques were beginning to appear; the results demonstrated that B cell depletion in the early stage of AD markedly accelerated and aggravated cognitive dysfunction and augmented the Aß burden in AD mice. Importantly, the experiments revealed 18 genes that were specifically upregulated and 7 genes that were specifically downregulated in B cells as the disease progressed, and several of these genes exhibited close correlation with AD. These findings identified possible B cell-based AD severity, which are anticipated to be conducive to the clinical identification of AD progression.

Panax notoginseng saponin attenuates the hypoxic-ischaemic injury in neonatal rats by regulating the expression of neurotrophin factors.

Neonatal hypoxic-ischaemic (HI) injury is a serious complication of neonatal asphyxia and the leading cause of neonatal acute death and chronic neurological injury, and the effective therapeutic method is lacking to improve patients' outcomes. We reported in this study that panax notoginseng saponin (PNS) may provide a treatment option for HI. HI model was established using neonatal Sprague-Dawley rats and then intraperitoneally injected with different dosage of PNS, once a day for 7 days. Histological staining and behavioural evaluations were performed to elucidate the pathological changes and neurobehavioural variation after PNS treatment. We found PNS administration significantly reduced the infarct volume of brain tissues and improved the autonomous activities of neonatal rats, especially with higher dosage. PNS treatment at 40 mg/kg reduced neuronal damage, suppressed neuronal apoptosis and depressed astroglial reactive response. Moreover, the long-term cognitive and motor functions were also improved after PNS treatment at 40 mg/kg. Importantly, PNS treatment elevated the levels of BDNF and TrkB but decreased the expression of p75NTR both in the cortex and hippocampus of HI rats. The therapeutic efficacy of PNS might be correlated with PNS-activated BDNF/TrkB signalling and inactivation of p75NTR expression, providing a novel potential therapy for alleviating HI injury.