Elucidation of CKAP4-remodeled cell mechanics in driving metastasis of bladder cancer through aptamer-based target discovery.

Metastasis contributes to the dismal prognosis of bladder cancer (BLCA). The mechanical status of the cell membrane is expected to mirror the ability of cell migration to promote cancer metastasis. However, the mechanical characteristics and underlying molecular profile associated with BLCA metastasis remain obscure. To study the unique cellular architecture and traits associated with cell migration, using a process called cell-based systematic evolution of ligands by exponential enrichment (cell-SELEX) we generated an aptamer-based molecular probe, termed spl3c, which identified cytoskeleton-associated protein 4 (CKAP4). CKAP4 was associated with tumor metastasis in BLCA, but we also found it to be a mechanical regulator of BLCA cells through the maintenance of a central-to-peripheral gradient of stiffness on the cell membrane. Notably, such mechanical traits were transportable through exosome-mediated intercellular CKAP4 trafficking, leading to significant enhancement of migration in recipient cells and, consequently, aggravating metastatic potential in vivo. Taken together, our study shows the robustness of this aptamer-based molecular tool for biomarker discovery, revealing the dominance of a CKAP4-induced central-to-peripheral gradient of membrane stiffness that benefits cell migration and delineating the role of exosomes in mediating mechanical signaling in BLCA metastasis.

Nucleic acid aptamer controls mycoplasma infection for inhibiting the malignancy of esophageal squamous cell carcinoma.

Esophageal cancer is one of the most frequent malignant tumors of the digestive tract, among which esophageal squamous cell carcinoma (ESCC) is the main pathological type worldwide. Previous studies have shown microbial infections in the upper digestive tract to be a potential risk factor in ESCC etiology. In this study, we identified that Mycoplasma hyorhinis infection promoted the malignancy of ESCC. In response, we generated a single-stranded DNA aptamer, ZY3A, against M. hyorhinis using the cell-SELEX strategy. The underlying recognition mechanism of ZY3A on M. hyorhinis involves its binding to M. hyorhinis-specific p37 protein. This tool allowed us to provide the first proof-of-concept evidence using a nucleic acid aptamer to control mycoplasma infection. More specifically, we found that ZY3A could neutralize M. hyorhinis infection on ESCC cells by blocking the interaction between p37 protein and its receptor TLR4 on the ESCC cell membrane. As a result, ZY3A inhibited the migration and invasion of M. hyorhinis-infected ESCC cells in vitro and metastasis in vivo. Taken together, these findings indicate that aptamer ZY3A is a potential candidate for development into a novel molecular tool for treatment of M. hyorhinis infection and a safe first-in-class M. hyorhinis-targeting antitumor agent.

Development of a DNA Aptamer against Multidrug-Resistant Hepatocellular Carcinoma for In Vivo Imaging.

Hepatocellular carcinoma (HCC) is a type of cancer that has high rates of recurrence and mortality. One of the most important factors that lead to treatment failure of HCC is the acquisition of multidrug resistance (MDR). Development of specific ligands for multidrug-resistant HCC will provide useful molecular tools for precise diagnosis and targeted theranostics. Herein, a multidrug-resistant HCC cell (HepG2/MDR)-specific aptamer was developed through Cell-SELEX (systematic evolution of ligands by exponential enrichment) technology. With dissociation constants lying in the nanomolar range, the molecularly designed PS-ZL-7c aptamer showed great selectivity to drug-resistant cancer cells. The in vivo imaging results illustrated that the PS-ZL-7c specifically accumulated in the drug-resistant tumors but not in drug-sensitive tumors and normal tissues, indicating that the PS-ZL-7c aptamer possessed excellent potential as a targeting ligand for precise diagnosis and target theranostics of multidrug-resistant HCC.

Investigating SARS-CoV-2 persistent contamination in different indoor environments.

Environmental contamination caused by COVID-19 patients could be a medium of transmission. Previous reports of SARS-CoV-2 in environmental surfaces were about short-term contamination. This study investigated SARS-CoV-2 RNA existence in room-temperature and low-temperature environments long after exposure (>28 days). A department store, where a COVID-19 outbreak was occurred in January 2020 (the epicenter of 43 COVID-19 patients), and a patient's apartment were included as room-temperature environments after being blocked for 57 days and 48 days, respectively. Seven cold storages and imported frozen foods inside were included as low-temperature environments (under -18 °C). Twenty food markets with potential contamination of imported frozen foods were also included to study the consecutive contamination. Information about temperature, relative humidity, and the number of days of environmental samples since the last exposure was collected and analyzed. In sum, 11,808 swab samples were collected before disinfection, of which 35 samples were positive. Persistent contamination of SARS-CoV-2 RNA was identified in the apartment (6/19), the department store (3/50), food packages in cold storages (23/1360), environmental surfaces of cold storages (2/345), and a package in the food market (1/10,034). Two positive samples were isolated from the bathroom of the apartment (66.7 %, 2/3), and doorknobs were proved with contamination in the apartment (40 %, 2/5) and cold storage (33.3 %, 1/3). The epidemiology information and environmental contamination results of an imported frozen food related COVID-19 case (138th COVID-19 patient in Tianjin) were analyzed. Based on the Ct values, the number of copies of two target genes was calculated by standard curves and linear regressions. In conclusion, SARS-CoV-2 RNA can be detected in room-temperature environments at least 57 days after the last exposure, much longer than previous reports. Based on the results of this study and previous studies, infectious SARS-CoV-2 could exist for at least 60 days on the surface of cold-chain food packages. Doorknobs and toilets (bathrooms) were important positions in COVID-19 control. High-risk populations of cold-chain-related logistic operations, such as porters, require strict prevention and high-level personal protection.

The regulation of NONO by USP11 via deubiquitination is linked to the proliferation of melanoma cells.

Ubiquitin-specific protease 11 (USP11) has been implicated in the regulation of DNA repair, apoptosis, signal transduction and cell cycle. It belongs to a USP subfamily of deubiquitinases. Although previous research has shown that USP11 overexpression is frequently found in melanoma and is correlated with a poor prognosis, the potential molecular mechanism of USP11 in melanoma remains indefinitive. Here, we report that USP11 and NONO colocalize and interact with each other in the nucleus of melanoma cells. As a result, the knockdown of USP11 decreases NONO levels. Whereas, overexpression of USP11 increases NONO levels in a dose-dependent manner. Furthermore, we reveal that USP11 protects NONO protein from proteasome-mediated degradation by removing poly-ubiquitin chains conjugated onto NONO. Functionally, USP11 mediated melanoma cell proliferation via the regulation of NONO levels because ablation of USP11 inhibits the proliferation which could be rescued by ectopic expression of NONO protein. Moreover, a significant positive correlation between USP11 and NONO concentrations was found in clinical melanoma samples. Collectively, these results demonstrate that USP11 is a new deubiquitinase of NONO and that the signalling axis of USP11-NONO is significantly involved in melanoma proliferation.

Expression of signaling components in embryonic eyelid epithelium.

Closure of an epithelium opening is a critical morphogenetic event for development. An excellent example for this process is the transient closure of embryonic eyelid. Eyelid closure requires shape change and migration of epithelial cells at the tip of the developing eyelids, and is dictated by numerous signaling pathways. Here we evaluated gene expression in epithelial cells isolated from the tip (leading edge, LE) and inner surface epithelium (IE) of the eyelid from E15.5 mouse fetuses by laser capture microdissection (LCM). We showed that the LE and IE cells are different at E15.5, such that IE had higher expression of muscle specific genes, while LE acquired epithelium identities. Despite their distinct destinies, these cells were overall similar in expression of signaling components for the "eyelid closure pathways". However, while the LE cells had more abundant expression of Fgfr2, Erbb2, Shh, Ptch1 and 2, Smo and Gli2, and Jag1 and Notch1, the IE cells had more abundant expression of Bmp5 and Bmpr1a. In addition, the LE cells had more abundant expression of adenomatosis polyposis coli down-regulated 1 (Apcdd1), but the IE cells had high expression of Dkk2. Our results suggest that the functionally distinct LE and IE cells have also differential expression of signaling molecules that may contribute to the cell-specific responses to morphogenetic signals. The expression pattern suggests that the EGF, Shh and NOTCH pathways are preferentially active in LE cells, the BMP pathways are effective in IE cells, and the Wnt pathway may be repressed in LE and IE cells via different mechanisms.

Disruption of aryl hydrocarbon receptor homeostatic levels during embryonic stem cell differentiation alters expression of homeobox transcription factors that control cardiomyogenesis.

BACKGROUND: The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that regulates the expression of xenobiotic detoxification genes and is a critical mediator of gene-environment interactions. Many AHR target genes identified by genome-wide gene expression profiling have morphogenetic functions, suggesting that AHR may play a role in embryonic development. OBJECTIVES: To characterize the developmental functions of the AHR, we studied the consequences of AHR activation by the agonist 2,3,7,8-tetrachlorodibenzo-p-doxin (TCDD), and the result of its repression by the antagonists 6,2,4-trimethoxyflavone and CH 223191 or by short-hairpin RNA (shRNA)-mediated Ahr knockdown during spontaneous differentiation of embryonic stem (ES) cells into cardiomyocytes. METHODS: We generated an AHR-positive cardiomyocyte lineage differentiated from mouse ES cells that expresses puromycin resistance and enhanced green fluorescent protein (eGFP) under the control of the Cyp1a1 (cytochrome P450 1a1) promoter. We used RNA sequencing (RNA.Seq) to analyze temporal trajectories of TCDD-dependent global gene expression in these cells during differentiation. RESULTS: Activation, inhibition, and knockdown of Ahr significantly inhibited the formation of contractile cardiomyocyte nodes. Global expression analysis of AHR-positive cells showed that activation of the AHR/TCDD axis disrupted the concerted expression of genes that regulate multiple signaling pathways involved in cardiac and neural morphogenesis and differentiation, including dozens of genes encoding homeobox transcription factors and Polycomb and trithorax group proteins. CONCLUSIONS: Disruption of AHR expression levels resulted in gene expression changes that perturbed cardiomyocyte differentiation. The main function of the AHR during development appears to be the coordination of a complex regulatory network responsible for attainment and maintenance of cardiovascular homeostasis.

Changes in the synaptic structure of hippocampal neurons and impairment of spatial memory in a rat model caused by chronic arsenite exposure.

Many epidemiological studies and in vitro experiments have found that chronic arsenic exposure may influence memory formation. The goal of this study was to create an animal model of memory impairment induced by chronic arsenite exposure and to study the underlying mechanisms. Sixty male Sprague-Dawley (SD) male rats were randomly divided into a control group, a low-dose sodium arsenite exposure group and a high-dose sodium arsenite exposure group. Sodium arsenite was administered by adding it to drinking water for 3 months. Then, the spatial memory of the rats was examined with Morris water maze and Y maze. The concentration of arsenic in the blood and the brain was determined by an atomic fluorescence absorption spectrometer. The ultra-structure of hippocampal neurons was observed by an electron microscope. Timm staining was used for observing mossy fibers. We found that the concentration of arsenic in the blood and the brain increased in a dose-response manner (P<0.05). The performance of rats in the arsenite exposed group (15 mg/kg) was significantly impaired in the Morris water maze and Y maze tasks than those in the control group (P<0.05). Sodium arsenite exposure resulted in abnormal structural changes in the myelin sheaths of nerve fibers and decreases in the terminals of mossy fibers. Together, chronic sodium arsenite exposure through drinking water results in detrimental changes in the neuronal synapses, which may contribute to the arsenite-induced impairment of spatial memory.