Chromosome-level genome assembly of the medicinal insect Blaps rhynchopetera using Nanopore and Hi-C technologies.

The Blaps rhynchopetera Fairmaire is a significant medicinal resource in southwestern China. We utilized Nanopore and Hi-C technologies in combination to generate a high-quality, chromosome-level assembly of the B. rhynchopetera genome and described its genetic features. Genome surveys revealed that B. rhynchopetera is a highly heterozygous species. The assembled genome was 379.24 Mb in size, of which 96.03% was assigned to 20 pseudochromosomes. A total of 212.93 Mb of repeat sequences were annotated and 26,824 protein-coding genes and 837 non-coding RNAs were identified. Phylogenetic analysis indicated that the divergence of the ancestors of B. rhynchopetera and its closely related species Tenebrio molitor at about 85.6 mya. The co-linearity analysis showed that some chromosomes of B. rhynchopetera may have happen fission events and it has a good synteny relationship with Tribolium castaneum. Furthermore, in the enrichment analyses, the gene families related to detoxification and immunity of B. rhynchopetera facilitated the understanding its environmental adaptations, which will serve as a valuable research resource for pest control strategies and conservation efforts of beneficial insects. This high-quality reference genome will also contribute to the conservation of insect species diversity and genetic resources.

Single-cell RNA sequencing reveals intratumoral heterogeneity and multicellular community in primary hepatocellular carcinoma underlying microvascular invasion.

Background: Microvascular invasion (MVI) is associated with an unfavorable prognosis and early recurrence of hepatocellular carcinoma (HCC), which is the crucial pathological hallmark of immunotherapy. While microvascular invasion (MVI) in hepatocellular carcinoma (HCC) currently lacks a detailed single-cell analysis of the tumor microenvironment (TME), it holds significant promise for immunotherapy using immune checkpoint inhibitors (ICI). Methods: We performed single-cell RNA sequencing (scRNA-seq) on 3 MVI positive (MVIP) and 14 MVI-negative (MVIN) tumor tissues, as well as their paired adjacent non-tumoral tissues. Results: We identified SPP1+ macrophages and CD4+ proliferative T cells as intertumoral populations critical for the formation of cold tumors and immunosuppressive environments in MVI-positive patients and verified their prognostic value in correlation with MVIP HCC patients. Additionally, we identified SPP1+ dominated interactions between SPP1+ macrophages and the immunosuppressive T population as contributors to MVI destruction and tumorigenesis. Conclusions: We provide a comprehensive single-cell atlas of HCC patients with MVI, shedding light on the immunosuppressive ecosystem and upregulated signaling associated with MVI. These findings demonstrate that intercellular mechanisms drive MVI and provide a potential immunotherapeutic target for HCC patients with HCC and underlying MVI.

Transcriptomic analyses reveals a diverse venom composition in Agelena limbata (Araneae: Agelenaidae).

Spider venom is a natural source of diverse biomolecules, but due to technical limitations, only a small fraction has been studied. With the advancement of omics technologies, research on spider venom has broadened, greatly promoting systematic studies of spider venom. Agelena limbata is a common spider found in vegetation, known for constructing funnel-shaped webs, and feeding on insects such as Diptera and Homoptera. However, due to its small size and the difficulty in obtaining venom, the composition of Agelena limbata venom has never been studied. In this study, a transcriptomics approach was used to analyze the toxin components in the venom of Agelena limbata, resulting in the identification of 28 novel toxin-like sequences and 24 peptidases. Based on sequence similarity and differences in cysteine motifs, the 28-novel toxin-like sequences were classified into 10 superfamilies. According to the results annotated in the database, the 24 peptidases were divided into six distinct families, with the serine protease family being the most common. A phylogenetic tree was constructed using the toxin-like sequences of Agelena limbata along with Psechrus triangulus and Hippasa lycosina. An analysis of the structural domains and motifs of Agelena limbata was also conducted. The results indicated that Agelena limbata is more distantly related to the other two species of funnel-web spiders, and that the toxin superfamily IX has a unique function compared to the other superfamilies. This study reveals the components of the Agelena limbata venom, deepening our understanding of it, and through bioinformatics analysis, has identified unique functions of the toxin superfamilies, providing a scientific basis for the development of bioactive drugs in the future.

Real-world effectiveness and safety of recombinant human endostatin plus PD-1 inhibitors and chemotherapy as first-line treatment for EGFR/ALK-negative, advanced or metastatic non-small cell lung cancer.

BACKGROUND: This study aimed to evaluate the effectiveness and safety of recombinant human endostatin (Rh-endostatin) plus programmed cell death 1 (PD-1) inhibitors and chemotherapy as first-line treatment for advanced or metastatic non-small cell lung cancer (NSCLC) in a real-world setting. METHODS: This was a retrospective study on patients with EGFR/ALK-negative, advanced or metastatic NSCLC. Patients received Rh-endostatin plus PD-1 inhibitors and chemotherapy every three weeks for 4 to 6 cycles. The primary endpoint was progression-free survival (PFS), and the secondary endpoints were objective response rate (ORR), disease control rate (DCR), overall survival (OS), and safety. RESULTS: A total of 68 patients were included in this retrospective analysis. As of data cutoff (December 13, 2022), the median follow-up of 21.4 months (interquartile range [IQR], 8.3-44.4 months). The median PFS and OS was 22.0 (95% confidence interval [CI]: 16.6-27.4) and 31.0 months (95% CI: 23.4-not evaluable [NE]), respectively. The ORR was 72.06% (95% CI: 59.85-82.27%), and DCR was 95.59% (95% CI: 87.64-99.08%). Patients with stage IIIB/IIIC NSCLC had significantly longer median PFS (23.4 vs. 13.2 months), longer median OS (not reached vs. 18.0 months), and higher ORR (89.2% vs. 51.6%) than those with stage IV NSCLC (all p ≤ 0.001). The ORR was higher in patients with high PD-L1 expression (tumor proportion score [TPS] ≥ 50%) than in those with low PD-L1 expression or positive PD-L1 expression (75% vs. 50%, p = 0.025). All patients experienced treatment-related adverse events (TRAEs), and ≥ grade 3 TRAEs occurred in 16 (23.53%) patients. CONCLUSIONS: Rh-endostatin combined with PD-1 inhibitors plus chemotherapy as first-line treatment yielded favorable effectiveness with a manageable profile in patients with advanced or metastatic NSCLC, representing a promising treatment modality.

Clinical characteristics and complication risks in data-driven clusters among Chinese community diabetes populations.

BACKGROUND: Novel diabetes phenotypes were proposed by the Europeans through cluster analysis, but Chinese community diabetes populations might exhibit different characteristics. This study aims to explore the clinical characteristics of novel diabetes subgroups under data-driven analysis in Chinese community diabetes populations. METHODS: We used K-means cluster analysis in 6369 newly diagnosed diabetic patients from eight centers of the REACTION (Risk Evaluation of cAncers in Chinese diabeTic Individuals) study. The cluster analysis was performed based on age, body mass index, glycosylated hemoglobin, homeostatic modeled insulin resistance index, and homeostatic modeled pancreatic ß-cell functionality index. The clinical features were evaluated with the analysis of variance (ANOVA) and chi-square test. Logistic regression analysis was done to compare chronic kidney disease and cardiovascular disease risks between subgroups. RESULTS: Overall, 2063 (32.39%), 658 (10.33%), 1769 (27.78%), and 1879 (29.50%) populations were assigned to severe obesity-related and insulin-resistant diabetes (SOIRD), severe insulin-deficient diabetes (SIDD), mild age-associated diabetes mellitus (MARD), and mild insulin-deficient diabetes (MIDD) subgroups, respectively. Individuals in the MIDD subgroup had a low risk burden equivalent to prediabetes, but with reduced insulin secretion. Individuals in the SOIRD subgroup were obese, had insulin resistance, and a high prevalence of fatty liver, tumors, family history of diabetes, and tumors. Individuals in the SIDD subgroup had severe insulin deficiency, the poorest glycemic control, and the highest prevalence of dyslipidemia and diabetic nephropathy. Individuals in MARD subgroup were the oldest, had moderate metabolic dysregulation and the highest risk of cardiovascular disease. CONCLUSION: The data-driven approach to differentiating the status of new-onset diabetes in the Chinese community was feasible. Patients in different clusters presented different characteristics and risks of complications.

Clinical significance and immune landscape of a novel immune cell infiltration-based prognostic model in lung adenocarcinoma.

Tumor-infiltrating immune cells (TICs) play a central role in the tumor microenvironment, which can reflect the host anti-tumor immune response. However, few studies have explored TICs in predicting the prognosis of lung adenocarcinoma (LUAD). In our study, we enrolled 2470 LUAD patients from TCGA and GEO databases, and the normalized enrichment scores for 65 immune cell types were quantified for each patient. An immune-related risk score (IRRS) was built on the basis of 17 selected TICs using LASSO regression analysis, and the results showed that high-risk patients were correlated with shorter survival time for the LUAD cohorts. Correlation analyses between IRRS and clinical characteristics were also evaluated to validate the clinical use of IRRS. In addition, we analyzed the differences in the distribution of immune cell infiltration and immunoregulatory gene expression, which may facilitate individual immunotherapy. Based on the above result, we conclude that IRRS can act as a powerful predictor for risk stratification and prognosis prediction, and may facilitate the decision-making process for LUAD patients.

From genome to proteome: Comprehensive identification of venom toxins from the Chinese funnel-web spider (Macrothelidae: Macrothele yani).

Macrothelidae is a family of mygalomorph spiders containing the extant genera Macrothele and Vacrothele. China is an important center of diversity for Macrothele with 65 % of the known species occurring there. Previous work on Macrothele was able to uncover several important toxin compounds including Raventoxin which may have applications in biomedicine and agricultural chemistry. Despite the importance of Macrothele spiders, high-quality reference genomes are still lacking, which hinders our understanding and application of the toxin compounds. In this study, we assembled the genome of the Macrothele yani to help fill gaps in our understanding of toxin biology in this lineage of spiders to encourage the future study and applications of these compounds. The final assembled genome was 6.79 Gb in total length, had a contig N50 of 21.44 Mb, and scaffold N50 of 156.16 Mb. Hi-C scaffolding assigned 98.19 % of the genome to 46 pseudo-chromosomes with a BUSCO score of 95.7 % for the core eukaryotic gene set. The assembled genome was found to contain 75.62 % repetitive DNA and a total of 39,687 protein-coding genes were annotated making it the spider genome with highest number of genes. Through integrated analysis of venom gland transcriptomics and venom proteomics, a total of 194 venom toxins were identified, including 38 disulfide-rich peptide neurotoxins, among which 12 were ICK knottin peptides. In summary, we present the first high-quality genome assembly at the chromosomal level for any Macrothelidae spider, filling an important gap in our knowledge of these spiders. Such high-quality genomic data will be invaluable as a reference in resolving Araneae spider phylogenies and in screening different spider species for novel compounds applicable to numerous medical and agricultural applications.

Two new species of Orchestina Simon, 1882 (Araneae, Oonopidae) from Cangshan Mountain, Yunnan, China.

Two new species of Orchestina, O.dapojing Tong & Yang, sp. nov. (♂♀) and O.hyperofrontata Tong & Yang, sp. nov. (♂) are described from Yunnan, China. Descriptions, diagnoses and photographs of habitus and copulatory organs are provided.

Mining channel-regulated peptides from animal venom by integrating sequence semantics and structural information.

Channel-regulated peptides (CRPs) derived from animal venom hold great promise as potential drug candidates for numerous diseases associated with channel proteins. However, discovering and identifying CRPs using traditional bio-experimental methods is a time-consuming and laborious process. While there were a few computational studies on CRPs, they were limited to specific channel proteins, relied heavily on complex feature engineering, and lacked the incorporation of multi-source information. To address these problems, we proposed a novel deep learning model, called DeepCRPs, based on graph neural networks for systematically mining CRPs from animal venom. By combining the sequence semantic and structural information, the classification performance of four CRPs was significantly enhanced, reaching an accuracy of 0.92. This performance surpassed baseline models with accuracies ranging from 0.77 to 0.89. Furthermore, we employed advanced interpretable techniques to explore sequence and structural determinants relevant to the classification of CRPs, yielding potentially valuable bio-function interpretations. Comprehensive experimental results demonstrated the precision and interpretive capability of DeepCRPs, making it an accurate and bio-explainable suit for the identification and categorization of CRPs. Our research will contribute to the discovery and development of toxin peptides targeting channel proteins. The source data and code are freely available at https://github.com/liyigerry/DeepCRPs.

Clinical Significance and Immune Infiltration Analyses of a Novel Nerve-Related lncRNA Signature in Gastric Cancer.

Gastric cancer (GC) is a progressive disease with high morbidity and mortality. Accumulating evidence indicated that nervous system-cancer crosstalk can affect the occurrence and progression of GC. However, the role of nerve-related lncRNAs (NRLs) in GC remains largely unexplored. In this study, a total of 441 nerve-related genes were collected from the KEGG database, and two approaches, unsupervised clustering and WGCNA, were employed to identify NRLs. Lasso regression analysis was then used to construct the nerve-related lncRNA signature (NRLS). Based on the expression profiles of 5 lncRNAs, we developed a stable NRLS to predict survival in GC patients, and survival analyses showed significantly shorter overall survival (OS) in patients with high NRLS. In addition, the NRLS was found to be positively correlated with immune characteristics, including tumor-infiltrating immune cells, immune modulators, cytokines and chemokines. We then analyzed the role of NRLS in predicting chemotherapy and immunotherapy responses, and constructed the OS nomogram combining NRLS and other clinical features. In conclusion, we constructed a robust NRLS model to stratify GC patients and predict the outcomes of chemotherapy and immunotherapy. This study can provide a new perspective for future individualized treatment of GC.

Transcriptome sequencing of wolf spider Lycosa sp. (Araneae: Lycosidae) venom glands provides insights into the evolution and diversity of disulfide-rich toxins.

Wolf spiders in the genus Lycosa are important pest predators in agroforestry ecosystems, capable of feeding on a wide range of pests through the use of complex venom which can to quickly immobilize and kill prey. Because of these characteristics the toxins in wolf spiders venom may prove to be natural sources for novel drug development and biopesticides. To better understand the toxins in Lycosa venom we sequenced the transcriptome from venom glands from an undescribed species of Lycosa and comparatively analyzed the data using known protein motifs. A series of 19 disulfide-rich peptide (DRP) toxin sequences were identified and categorized into seven groups based on the number and arrangement of cysteine residues. Notably, we identified three peptide sequences with low identity to any known toxin, which may be toxin peptides specific to this species of Lycosa. In addition, to further understand the evolutionary relationships of disulfide-rich peptide toxins in spider venom, we constructed phylogenetic trees of DRP toxins from three spiders species and found that the Lycosa sp. DRPs are comparatively diverse with previous research results. This study reveals the toxin diversity of wolf spiders (Lycosa sp.) at the transcriptomic level and provides initial insights into the evolution of DRP toxins in spiders, enriching our knowledge of toxin diversity and providing new compounds for functional studies.

Three new species of Camptoscaphiella Caporiacco, 1934 (Araneae, Oonopidae) from Yunnan Province, China.

Background: Camptoscaphiella Caporiacco, 1934 is a small genus of oonopid spiders that currently contains 20 species, of which five have been recorded in Yunnan, China. New information: Three new species of Camptoscaphiella, C.hudie Tong & Yang, sp. nov. (female), C.yinglefeng Tong & Yang, sp. nov. (female, male) and C.yujufeng Tong & Yang, sp. nov. (male) are described from Yunnan, China. Descriptions, diagnoses and photographs are provided.

Three new species of the genus Trilacuna Tong & Li, 2007 (Araneae, Oonopidae) from Yunnan Province, China.

Three new species of the genus Trilacuna Tong & Li, 2007, T.cangshan Tong, Yang & Zhang, sp. nov. (♂), T.wumanshan Tong, Yang & Zhang, sp. nov. (♂), and T.xiaoheishan Tong, Yang & Zhang, sp. nov. (♂♀) are described from Yunnan, China. Descriptions, diagnoses, and photographs are provided.

Nomogram for predicting survival in patients with advanced hepatocellular carcinoma treated with PD-1 inhibitors: incorporating pre-treatment and post-treatment clinical parameters.

BACKGROUND: Immunotherapy has transformed cancer treatment patterns for advanced hepatocellular carcinoma (aHCC) in recent years. Therefore, the identification of predictive biomarkers has important clinical implications. METHODS: We collected medical records from 117 aHCC patients treated with anti-PD-1 antibody. Kaplan-Meier analysis and Cox proportional hazard regression were used to evaluate the association between peripheral blood biomarkers and overall survival (OS) and progression-free survival (PFS). Finally, the prognostic nomogram was constructed. RESULTS: The mPFS and mOS were 7.0 months and 18.7 months, respectively. According to Kaplan-Meier analysis and Cox regression analysis, we regarded the treatment regimen (p = 0.020), hemoglobin (Hb) at 6-week (p = 0.042), neutrophil-to-lymphocyte ratio (NLR) at 6-week (p < 0.001), system immune inflammation index (SII) at 6-week (p = 0.125) as predictors of PFS, and alpha fetoprotein (AFP) (p = 0.035), platelet-to-lymphocyte ratio (PLR) (p = 0.012), Hb at 6-week (p = 0.010) and NLR at 6-week (p = 0.020) as predictors of OS. Furthermore, the results suggest that the OS and PFS nomogram model were in agreement with actual observations. CONCLUSION: Biomarkers in peripheral blood can predict the prognosis of patients with aHCC treated with anti-PD-1 antibody. The development of nomogram models can help us to screen potential patients who can benefit from immunotherapy.

The therapeutic effect of wasp venom (Vespa magnifica, Smith) and its effective part on rheumatoid arthritis fibroblast-like synoviocytes through modulating inflammation, redox homeostasis and ferroptosis.

ETHNOPHARMACOLOGICAL RELEVANCE: Rheumatoid arthritis (RA) is a chronic inflammatory disease that is related to the aberrant proliferation of fibroblast-like synoviocytes (FLS). Wasp venom (WV, Vespa magnifica, Smith), an insect secretion, has been used to treat RA in Chinese Jingpo national minority's ancient prescription. However, the potential mechanisms haven't been clarified. AIM OF THE STUDY: The purposes of this paper were two-fold. First, to investigate which was the best anti-RA effective part of WV-I (molecular weight less than 3 kDa), WV-II (molecular weight 3-10 kDa) and WV-III (molecular weight more than 10 kDa) that were separated from WV. Second, to explore the underlying molecular mechanism of WV and WV-II that was best effective part in RA. MATERIALS AND METHODS: The wasps were electrically stimulated and the secretions were collected. WV-I, WV-II and WV-III were acquired by ultracentrifuge method according to molecular weight. Next, WV, WV-I, WV-II and WV-III were identified by HPLC. Functional annotation and pathway analysis of WV used to bioinformatics analysis. RNA-seq analyses were constructed to identify differentially expressed genes (DEGs). GO and KEGG pathway analyses were performed by Metascape database. STRING was used to analyze the PPI network from DEGs. Next, PPI network was visualized using Cytoscape that based on MCODE. The pivotal genes of PPI network and MCODE analysis were verified by qRT-PCR. Subsequently, MH7A cells were performed by MTT assay to evaluate the ability of inhibiting cell proliferation. Luciferase activity assay was conducted in HepG2/STAT1 or HepG2/STAT3 cells to assess STAT1/3 sensitivity of WV, WV-I, WV-II and WV-III. Additionally, interleukin (IL)-1ß and IL-6 expression levels were detected by ELISA kits. Intracellular thioredoxin reductase (TrxR) enzyme was evaluated by TrxR activity assay kit. ROS levels, lipid ROS levels and Mitochondrial membrane potential (MMP) were assessed by fluorescence probe. Cell apoptosis and MMP were measured by using flow cytometry. Furthermore, the key proteins of JAK/STAT signaling pathway, protein levels of TrxR and glutathione peroxidase 4 axis (GPX4) were examined by Western blotting assay. RESULTS: RNA-sequencing analysis of WV displayed be related to oxidation-reduction, inflammation and apoptosis. The data displayed that WV, WV-II and WV-III inhibited significantly cells proliferation in human MH7A cell line compared to WV-I treatment group, but WV-III had no significant suppressive effect on luciferase activity of STAT3 compared with IL-6-induced group. Combined with earlier reports that WV-III contained major allergens, we selected WV and WV-II further to study the mechanism of anti-RA. In addition, WV and WV-II decreased the level of IL-1ß and IL-6 in TNF-α-induced MH7A cells via inactivating of JAK/STAT signaling pathway. On the other hand, WV and WV-II down-regulated the TrxR activity to produce ROS and induce cell apoptosis. Furthermore, WV and WV-II could accumulate lipid ROS to induce GPX4-mediated ferroptosis. CONCLUSIONS: Taken together, the experimental results revealed that WV and WV-II were potential therapeutic agents for RA through modulating JAK/STAT signaling pathways, redox homeostasis and ferroptosis in MH7A cells. Of note, WV-II was an effective part and the predominant active monomer in WV-II will be further explored in the future.

Transcriptome-based analyses reveal venom diversity in two araneomorph spiders, Psechrus triangulus and Hippasa lycosina.

The spiders Psechrus triangulus and Hippasa lycosina are widely distributed in Yunnan Province, China, and are important natural enemies of agricultural pests, yet studies regarding the composition of their venom are lacking. In this study, cDNA libraries were constructed from venom gland tissue of P. triangulus and H. lycosina and used for transcriptomic analysis. From the analysis, 39 and 31 toxin-like sequences were predicted for P. triangulus and H. lycosina, respectively. The predicted neurotoxin sequences were categorized according to cysteine sequence motifs, and the predicted neurotoxin sequences of P. triangulus and H. lycosina could be classified into 9 and 6 toxin families, respectively. In addition, potential acetylcholinesterase, hyaluronidase, and astaxanthin-like metalloproteinases were identified through annotation. In summary, transcriptomic techniques were invaluable in mining the gene expression information from these two spider species to explore the toxin composition of their venom and determine how they differ. Studies of this type provide essential baseline data for studying the evolution and physiological activities of spider toxins and for the potential development of medicinal compounds.

A label-free fluorescent aptasensor based on a novel exponential rolling circle amplification for highly sensitive ochratoxin A detection.

Rapid and sensitive analysis of ochratoxin A (OTA) plays an important role in food safety. Here, an aptasensor based on novel exponential rolling circle amplification (ERCA) was proposed for ultrasensitive and label-free fluorescence detection of OTA. The attachment of OTA to its aptamer could release H and rapidly hybridize with CT to initiate rolling circle amplification (RCA). The amplicons could further displace H from APH to initiate recycled RCA, achieving exponential growth of amplification products that contained G4 dimers for lighting up ThT. Benefiting from the exponential amplification efficiency of the ERCA strategy and the high fluorescence quantum yield of G4 dimer/ThT, this strategy exhibited a wide linear range from 10 fg/mL to 10 ng/mL with a detection limit of 4.3 fg/mL. In addition, the aptasensor displayed satisfactory recoveries in real sample analysis. We believe that this novel aptasensor possesses promising application prospects in food safety and medicine detection.

A domino-like localized cascade toehold assembly amplification-based DNA nanowire for microRNA imaging in living cells.

High sensitivity and specificity imaging of miRNA in living cells plays an important role in understanding miRNA-related regulation and pathological research. Localized DNA circuits have shown good performance in reaction rate and sensitivity and have been proposed for sensitive imaging of miRNA in living cells. However, most reported localized DNA circuits have a high risk of derailment or a limited loading rate capacity, which hinder their further application. To solve these issues, we herein developed a domino-like localized cascade toehold assembly (LCTA) amplification-based DNA nanowire to achieve highly sensitive and highly specific imaging of miRNAs in living cells by using DNA nanowires as reactant delivery vehicles and confining both reactant probes in a compact space. The LCTA is constructed by interval hybridization of DNA double-stranded probe pairs to a DNA nanowire with multiplex footholds generated by alternating chain hybridization. Due to the localized effect, the LCTA showed high reaction kinetics and sensitivity, and the method could detect miRNAs as low as 51 pM. The LCTA was proven to be able to accurately distinguish the miRNA expression difference between normal cells and cancer cells. In particular, the developed LCTA could be used to construct an OR logic gate to simultaneously image the total amount of multiple miRNAs in living cells. We believe that the developed LCTA can be an effective intracellular nucleic acid imaging tool and can promote the development of nucleic acid-related clinical disease diagnosis and DNA logical sensors.

Description of a new genus and two new species of the funnel-web mygalomorph (Araneae: Mygalomorphae: Macrothelidae) from China with notes on taxonomic amendments.

A new genus of the spider family Macrothelidae Simon, 1892, Vacrothele Tang Yang gen. nov. is described, along with two new species: V. pseudohunanica sp. nov., V. uncata sp. nov.. Three Macrothele species are transferred to the new genus: V. hunanica (Zhu Song, 2000) comb. nov., V. digitata (Chen Jiang, 2020) comb. nov., and V. palpator (Pocock, 1901) comb. nov..

Smart Hairpins@MnO2 Nanosystem Enables Target-Triggered Enzyme-Free Exponential Amplification for Ultrasensitive Imaging of Intracellular MicroRNAs in Living Cells.

Sensitive and specific imaging of microRNA (miRNA) in living cells is of great value for disease diagnosis and monitoring. Hybridization chain reaction (HCR) and DNAzyme-based methods have been considered as powerful tools for miRNA detection, with low efficient intracellular delivery and limited amplification efficiency. Herein, we propose a Hairpins@MnO2 nanosystem for intracellular enzyme-free exponential amplification for miRNA imaging. The enzyme-free exponential amplification is based on the synergistic cross-activation between HCR and DNAzymes. The MnO2 nanosheets were employed as the carrier of three kinds of hairpin DNA probes and further provided appropriate Mn2+ as DNAzyme cofactors in the living cell. Upon entering cells and in the presence of highly expressed glutathione (GSH) in tumors, MnO2 is reduced to release Mn2+ and the three kinds of hairpin DNA probes. In the presence of target miRNA, the released hairpin DNA H1 and H2 probes self-assemble via HCR into the wire-shaped active Mn2+-based DNAzymes which further catalyze the cleavage of H3 to generate numerous new triggers to reversely stimulate HCR amplifiers, thus offering tremendously amplified Förster resonance energy transfer readout. The method has a detection limit of 33 fM, which is 2.4 × 104 times lower than that of the traditional HCR system. The developed method also has a high specificity; even miRNAs with a single base difference can be distinguished. Live cell imaging experiments confirmed that this Hairpins@MnO2 nanosystem allows accurate differentiation of miRNA expression of cancer cells and normal cells. The method holds great potential in biological research of nucleic acids.