Construction of a Spatial-Confined Self-Stacking Catalytic Circuit for Rapid and Sensitive Imaging of Piwi-Interacting RNA in Living Cells.

Piwi-interacting RNAs (piRNAs) are small noncoding RNAs that repress transposable elements to maintain genome integrity. The canonical catalytic hairpin assembly (CHA) circuit relies on random collisions of free-diffused reactant probes, which substantially slow down reaction efficiency and kinetics. Herein, we demonstrate the construction of a spatial-confined self-stacking catalytic circuit for rapid and sensitive imaging of piRNA in living cells based on intramolecular and intermolecular hybridization-accelerated CHA. We rationally design a 3WJ probe that not only accelerates the reaction kinetics by increasing the local concentration of reactant probes but also eliminates background signal leakage caused by cross-entanglement of preassembled probes. This strategy achieves high sensitivity and good specificity with shortened assay time. It can quantify intracellular piRNA expression at a single-cell level, discriminate piRNA expression in tissues of breast cancer patients and healthy persons, and in situ image piRNA in living cells, offering a new approach for early diagnosis and postoperative monitoring.

MLH1 Inhibits Metastatic Potential of Pancreatic Ductal Adenocarcinoma via Downregulation of GPRC5C.

DNA mismatch repair gene MutL homolog-1 (MLH1) has divergent effects in many cancers; however, its impact on the metastasis of pancreatic ductal adenocarcinoma (PDAC) remains unclear. In this study, MLH1 stably overexpressed (OE) and knockdowned (KD) sublines were established. Wound healing and transwell assays were used to evaluate cell migration/invasion. In vivo metastasis was investigated in orthotopic implantation models (severe combined immunodeficiency mice). RT-qPCR and western blotting were adopted to show gene/protein expression. MLH1 downstream genes were screened by transcriptome sequencing. Tissue microarray-based immunohistochemistry was applied to determine protein expression in human specimens. In successfully generated sublines, OE cells presented weaker migration/invasion abilities, compared with controls, whereas in KD cells, these abilities were significantly stronger. The metastasis-inhibitory effect of MLH1 was also observed in mice. Mechanistically, G protein-coupled receptor, family C, group 5, member C (GPRC5C) was a key downstream gene of MLH1 in PDAC cells. Subsequently, transient GPRC5C silencing effectively inhibited cell migration/invasion and remarkably reversed the proinvasive effect of MLH1 knockdown in KD cells. In animal models and human PDAC tissues, tumoral GPRC5C expression, negatively associated with MLH1 expressions, was positively correlated with histologic grade, vessel invasion, and poor cancer-specific survival. In conclusion, MLH1 inhibits the metastatic potential of PDAC via downregulation of GPRC5C.

Construction of an Enzymatically Controlled DNA Nanomachine for One-Step Imaging of Telomerase in Living Cells.

Telomerase is a basic reverse transcriptase that maintains the telomere length in cells, and accurate and specific sensing of telomerase in living cells is critical for medical diagnostics and disease therapeutics. Herein, we demonstrate for the first time the construction of an enzymatically controlled DNA nanomachine with endogenous apurinic/apyrimidinic endonuclease 1 (APE1) as a driving force for one-step imaging of telomerase in living cells. The DNA nanomachine is designed by rational engineering of substrate probes and reporter probes embedded with an enzyme-activatable site (i.e., AP site) and their subsequent assembly on a gold nanoparticle (AuNP). Upon recognition and cleavage of the AP site in the substrate probe by APE1, the loop of the substrate probe unfolds, exposing telomeric primer (TP) with the 3'-OH end. Subsequently, the TP is elongated by telomerase at the 3'-OH end to generate a long telomeric product. The resultant telomeric product acts as a swing arm that can hybridize with a reporter probe to initiate the APE1-powered walking reaction, ultimately generating a significantly enhanced fluorescence signal. Notably, endogenous APE1 is used as the driving force of the DNA nanomachine, avoiding the introduction of exogenous auxiliary cofactors into the cellular microenvironment. Owing to the high kinetics and high amplification efficiency of the APE1-powered DNA nanomachine, this strategy enables one-step sensitive sensing of telomerase in vitro and in vivo. It can successfully discriminate telomerase activity between cancer cells and normal cells, screen telomerase inhibitors, and monitor the variations of telomerase activity in living cells, offering a prospective platform for molecular diagnostics and drug discovery.

Bacteremia caused by Nocardia farcinica: a case report and literature review.

BACKGROUND: Nocardia farcinica is one of the most common Nocardia species causing human infections. It is an opportunistic pathogen that often infects people with compromised immune systems. It could invade human body through respiratory tract or skin wounds, cause local infection, and affect other organs via hematogenous dissemination. However, N. farcinica-caused bacteremia is uncommon. In this study, we report a case of bacteremia caused by N. farcinica in China. CASE PRESENTATION: An 80-year-old woman was admitted to Peking Union Medical College Hospital with recurrent fever, right abdominal pain for one and a half month, and right adrenal gland occupation. N. farcinica was identified as the causative pathogen using blood culture and plasma metagenomics next-generation sequencing (mNGS). The clinical considerations included bacteremia and adrenal gland abscess caused by Nocardia infection. As the patient was allergic to sulfanilamide, imipenem/cilastatin and linezolid were empirically administered. Unfortunately, the patient eventually died less than a month after the initiation of anti-infection treatment. CONCLUSION: N. farcinica bacteremia is rare and its clinical manifestations are not specific. Its diagnosis depends on etiological examination, which can be confirmed using techniques such as Sanger sequencing and mNGS. In this report, we have reviewed cases of Nocardia bloodstream infection reported in the past decade, hoping to improve clinicians' understanding of Nocardia bloodstream infection and help in its early diagnosis and timely treatment.

HK2 and LDHA upregulation mediate hexavalent chromium-induced carcinogenesis, cancer development and prognosis through miR-218 inhibition.

Hexavalent chromium [Cr(VI)] is one of the most common environmental contaminants due to its tremendous industrial applications, but its effects and mechanism remain to be investigated. Our previous studies showed that Cr(VI) exposure caused malignant transformation and tumorigenesis. This study showed that glycolytic proteins HK2 and LDHA levels were statistically significant changed in blood samples of Cr(VI)-exposed workers and in Cr-T cells compared to the control subjects and parental cells. HK2 and LDHA knockdown inhibited cell proliferation and angiogenesis, and higher HK2 and LDHA expression levels are associated with advanced stages and poor prognosis of lung cancer. We found that miR-218 levels were significantly decreased and miR-218 directly targeted HK2 and LDHA for inhibiting their expression. Overexpression of miR-218 inhibited glucose consumption and lactate production in Cr-T cells. Further study found that miR-218 inhibited tumor growth and angiogenesis by decreasing HK2 and LDHA expression in vivo. MiR-218 levels were negatively correlated with HK2 and LDHA expression levels and cancer development in human lung and other cancers. These results demonstrated that miR-218/HK2/LDHA pathway is vital for regulating Cr(VI)-induced carcinogenesis and human cancer development.

Genome-wide analysis of in vivo-evolved Candida auris reveals multidrug-resistance mechanisms.

Candida auris, an emerging and multidrug-resistant fungal pathogen, has led to numerous outbreaks in China. While the resistance mechanisms against azole and amphotericin B have been studied, the development of drug resistance in this pathogen remains poorly understood, particularly in in vivo-generated drug-resistant strains. This study employed pathogen whole-genome sequencing to investigate the epidemiology and drug-resistance mutations of C. auris using 16 strains isolated from two patients. Identification was conducted through Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and antimicrobial susceptibilities were assessed using broth microdilution and Sensititre YeastOne YO10. Whole-genome sequencing revealed that all isolates belonged to the South Asian lineage, displaying genetic heterogeneity. Despite low genetic variability among patient isolates, notable mutations were identified, including Y132F in ERG11 and A585S in TAC1b, likely linked to increased fluconazole resistance. Strains from patient B also carried F214L in TAC1b, resulting in a consistent voriconazole minimum inhibitory concentration of 4 µg/mL across all isolates. Furthermore, a novel frameshift mutation in the SNG1 gene was observed in amphotericin B-resistant isolates compared to susceptible ones. Our findings suggest the potential transmission of C. auris and emphasize the need to explore variations related to antifungal resistance. This involves analyzing genomic mutations and karyotypes, especially in vivo, to compare sensitive and resistant strains. Further monitoring and validation efforts are crucial for a comprehensive understanding of the mechanisms of drug resistance in C. auris.

Comparison of Ba-Hao burn ointment gauze and petrolatum gauze in split graft donor site healing: A randomized, prospective, and self-control study.

Background and Aims: To assess patient comfort, wound healing, and scarring at the 6-month follow-up of split-skin graft donor sites treated with Ba-Hao burn ointment (BHBO) gauze, a compound preparation of traditional Chinese medicine since 1970s, compared with petrolatum gauze. Methods: Thirty patients admitted to the Department of Burns of the First Affiliated Hospital of Anhui Medical University between September 2021 and September 2022 participated in this randomized, prospective, self-control clinical study. After harvesting the split skin, donor sites were divided into two parts along the midline. BHBO gauze was applied to half of the donor wounds, and petrolatum gauze was applied to the other half. The wound healing time, pain scores on the postoperative Days 3, 6, and 9, and Vancouver Scar Scale (VSS) score at the 6-month follow-up were assessed. Results: The wound healing time was significantly shorter in the BHBO group than in the control group (10.07 ± 1.48 days vs. 11.50 ± 1.74 days, p < 0.001). On postoperative Days 3 and 6, the pain scores quantified by visual analog scores were significantly lower in the BHBO group than in the control group (5.33 ± 1.54 and 4.17 ± 1.51, respectively vs. 7.57 ± 1.41 and 5.20 ± 1.47, respectively). The difference in the visual analog scale score on postoperative Day 9 between the groups was not significant (p > 0.05). Microbiological assessment revealed the absence of bacterial contamination in both groups. At the 6-month follow up, the VSS score was significantly lower in the BHBO group (6.67 ± 1.92) than in the control group (9.57 ± 1.55). Conclusion: BHBO resulted in faster donor-site healing, reduced postoperative pain, and improved scar quality at the 6-month follow-up than petrolatum gauze alone.

Insight into the role of non-coding RNA in the diagnosis and treatment of retinitis pigmentosa.

Retinitis pigmentosa (RP) is the most common type of inherited retinal dystrophy. The course of RP is irreversible and leads to progressive loss of vision. It is characterized by hypotrophic degeneration of photoreceptor cells and retinal pigment epithelium. Multiple factors are involved in the development of the disease, including apoptosis, oxidative stress, and inflammatory/immune responses. In the past decades, gene therapy, stem cell therapy and other therapeutic approaches have been extensively investigated. However, due to the heritability and high heterogeneity of the disease and the difficulty in diagnosis and treatment, there is still a lack of standardized and effective therapies. Therefore, there is a need to develop new diagnostic and therapeutic approaches suitable for diseases with pathogenic mutations. With the understanding of the interaction between gene expression regulation and retinal pathology, the value of clinical applications of non-coding RNAs (ncRNAs) in retinal degeneration has gained attention. There is growing evidence that ncRNAs are widely distributed and involved in the regulation of multiple biological processes in the retina as well as processes associated with the development of RP, making them promising biomarkers for the diagnosis, treatment, and prognosis of RP. This paper reviews the crosstalk between ncRNA and RP, systematically discusses the role of ncRNAs in normal retinal cell physiology and RP pathogenesis and explores the potential of ncRNAs as therapeutic agents for clinical applications in RP.

Potential application of Nardostachyos Radix et Rhizoma-Rhubarb for the treatment of diabetic kidney disease based on network pharmacology and cell culture experimental verification.

BACKGROUND: Diabetic kidney disease (DKD) is one of the serious complications of diabetes mellitus, and the existing treatments cannot meet the needs of today's patients. Traditional Chinese medicine has been validated for its efficacy in DKD after many years of clinical application. However, the specific mechanism by which it works is still unclear. Elucidating the molecular mechanism of the Nardostachyos Radix et Rhizoma-rhubarb drug pair (NRDP) for the treatment of DKD will provide a new way of thinking for the research and development of new drugs. AIM: To investigate the mechanism of the NRDP in DKD by network pharmacology combined with molecular docking, and then verify the initial findings by in vitro experiments. METHODS: The Traditional Chinese Medicine Systems Pharmacology (TCMSP) database was used to screen active ingredient targets of NRDP. Targets for DKD were obtained based on the Genecards, OMIM, and TTD databases. The VENNY 2.1 database was used to obtain DKD and NRDP intersection targets and their Venn diagram, and Cytoscape 3.9.0 was used to build a "drug-component-target-disease" network. The String database was used to construct protein interaction networks. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and Gene Ontology analysis were performed based on the DAVID database. After selecting the targets and the active ingredients, Autodock software was used to perform molecular docking. In experimental validation using renal tubular epithelial cells (TCMK-1), we used the Cell Counting Kit-8 assay to detect the effect of NRDP on cell viability, with glucose solution used to mimic a hyperglycemic environment. Flow cytometry was used to detect the cell cycle progression and apoptosis. Western blot was used to detect the protein expression of STAT3, p-STAT3, BAX, BCL-2, Caspase9, and Caspase3. RESULTS: A total of 10 active ingredients and 85 targets with 111 disease-related signaling pathways were obtained for NRDP. Enrichment analysis of KEGG pathways was performed to determine advanced glycation end products (AGEs)-receptor for AGEs (RAGE) signaling as the core pathway. Molecular docking showed good binding between each active ingredient and its core targets. In vitro experiments showed that NRDP inhibited the viability of TCMK-1 cells, blocked cell cycle progression in the G0/G1 phase, and reduced apoptosis in a concentration-dependent manner. Based on the results of Western blot analysis, NRDP differentially downregulated p-STAT3, BAX, Caspase3, and Caspase9 protein levels (P < 0.01 or P < 0.05). In addition, BAX/BCL-2 and p-STAT3/STAT3 ratios were reduced, while BCL-2 and STAT3 protein expression was upregulated (P < 0.01). CONCLUSION: NRDP may upregulate BCL-2 and STAT3 protein expression, and downregulate BAX, Caspase3, and Caspase9 protein expression, thus activating the AGE-RAGE signaling pathway, inhibiting the vitality of TCMK-1 cells, reducing their apoptosis. and arresting them in the G0/G1 phase to protect them from damage by high glucose.

[Study on the molecular mechanism of circ_0000326 regulating the proliferation, invasion and migration of oral squamous cell carcinoma HSC3 cells by targeting miR-567].

PURPOSE: To explore the molecular mechanism of circ_0000326 regulating proliferation, invasion and migration of oral squamous cell carcinoma HSC3 cells. METHODS: Cancerous tissue and adjacent tissue specimens of 45 patients with oral squamous cell carcinoma (OSCC) admitted to the Second People's Hospital of Hefei from March 2020 to June 2021 were collected. qRT-PCR was used to detect the expression levels of circ_0000326 and miR-567. CCK-8, plate clone formation test, scratch test and Transwell test were used to detect cell proliferation, clone formation, migration and invasion. Dual luciferase reporter experiment was used to detect the targeting relationship between circ_0000326 and miR-567. Western blot was used to quantify E-cadherin and N-cadherin protein. SPSS 21.0 software package was used for statistical analysis. RESULTS: circ_0000326 expression was 4.01±0.29 in OSCC and 1.00±0.13 in paracancerous tissues, while miR-567 expression was 0.28±0.03 and 1.00±0.10, respectively, with significant differences. Compared with the si-NC group, the cell viability and the number of cell clones in the si-circ_0000326 group were significantly decreased(P＜0.05). Compared with the si-NC group, the number of invasive cells and scratch healing rate in the si-circ_0000326 group were significantly decreased (P＜0.05), the expression level of E-cadherin protein was significantly increased (P＜0.05), and the expression level of N-cadherin protein was significantly decreased(P＜0.05). Additionally, circ_0000326 targeted miR-567. miR-567 expression was 1.00±0.00 in pcDNA group, 0.44±0.04 in pcDNA-circ_0000326 group, 0.99±0.06 in si-NC group, and 2.92±0.25 in si-circ_0000326 group with significant differences. Compared with miR-NC group, the cell viability, scratch healing rate, the number of cell clones and the number of invasive cells of miR-567 group were decreased, while E-cadherin protein level was increased(P＜0.05). Compared with si-circ_0000326+anti-miR-NC group, the cell viability, scratch healing rate, N-cadherin protein level, the number of cell clones and the number of invasive cells of si-circ_0000326+anti-miR-567 group were increased(P＜0.05), while E-cadherin protein level was decreased(P＜0.05). CONCLUSIONS: Interference with the expression of circ_0000326 could reduce the ability of OSCC cell proliferation, colony formation, migration and invasion by promoting the expression of miR-567.

Enzymatic DNA repairing amplification-powered construction of an Au nanoparticle-based nanosensor for single-molecule monitoring of cytosine deaminase activity in cancer cells.

APOBEC3A (A3A) is a cytidine deaminase with critical roles in molecular diagnostics. Herein, we demonstrate the enzymatic DNA repairing amplification-powered construction of an Au nanoparticle-based nanosensor for single-molecule monitoring of A3A activity in cancer cells. Target A3A can convert cytosine (C) in substrate probe to uracil (U), and then the template binds with substrate probe to form a dsDNA containing U/A base pairs. Uracil DNA glycosylase (UDG) excises the U base to produce an apurinic/apyrimidinic (AP) site that can be cleaved by apurinic/apyrimidic endonuclease 1 (APE1) to obtain the substrate fragment with 3'-OH end. Subsequently, the substrate fragment initiates cyclic enzymatic repairing amplification (ERA), releasing trigger-1 and trigger-2. The resultant trigger-1 can act as the primer to induce multiple cycles of cyclic ERA, producing numerous trigger-1 and trigger-2. The hybridization of trigger-2 with signal probe forms the dsDNA duplexes with an AP site, inducing the cyclic cleavage of signal probes by APE1 to release abundant Cy5 molecules from the AuNPs. Released Cy5 molecules can be easily quantified by single-molecule imaging. This nanosensor allows for specific and sensitive detection of A3A activity with a detection limit of 0.855 aM, and it can further measure kinetic parameters, screen inhibitors, and quantify endogenous A3A activity at the single-cell level, with prospect application in disease diagnostics and therapy.