Single-cell analysis of p53 transitional dynamics unravels stimulus- and cell type-dependent signaling output motifs.

BACKGROUND: To understand functional changes of complex biological networks, mathematical modeling of network topologies provides a quantitative measure of the way biological systems adapt to external stimuli. However, systemic network topology-based analysis often generates conflicting evidence depending on specific experimental conditions, leading to a limited mechanistic understanding of signaling networks and their differential dynamic outputs, an example of which is the regulation of p53 pathway responses to different stress stimuli and in variable mammalian cell types. Here, we employ a network motif approach to dissect key regulatory units of the p53 pathway and elucidate how network activities at the motif level generate context-specific dynamic responses. RESULTS: By combining single-cell imaging and mathematical modeling of dose-dependent p53 dynamics induced by three chemotherapeutics of distinct mechanism-of-actions, including Etoposide, Nutlin-3a and 5-fluorouracil, and in five cancer cell types, we uncovered novel and highly variable p53 dynamic responses, in particular p53 transitional dynamics induced at intermediate drug concentrations, and identified the functional roles of distinct positive and negative feedback motifs of the p53 pathway in modulating the central p53-Mdm2 negative feedback to generate stimulus- and cell type-specific signaling responses. The mechanistic understanding of p53 network dynamics also revealed previously unknown mediators of anticancer drug actions and phenotypic variations in cancer cells that impact drug sensitivity. CONCLUSIONS: Our results demonstrate that transitional dynamics of signaling proteins such as p53, activated at intermediate stimulus levels, vary the most between the dynamic outputs of different generic network motifs and can be employed as novel quantitative readouts to uncover and elucidate the key building blocks of large signaling networks. Our findings also provide new insight on drug mediators and phenotypic heterogeneity that underlie differential drug responses.

[Source Analysis of Ethylene Oxide Sterilization Residues in Medical Devices].

At present, the most commonly used sterilization method for medical devices is ethylene oxide sterilization. The residue after sterilization is closely related to the health of the people who contacted with the medical devices. The study team analyzed the possible residues of medical devices after sterilization with ethyleneoxide. It is suggested that ethylene oxide, 2-chloroethanol and ethylene glycol should be evaluated comprehensively through the analysis of factors such as production links of medical devices, production process of ethylene oxide, sterilization process, sterilization environment and detection method.

Deep Learning-Based 3D Single-Cell Imaging Analysis Pipeline Enables Quantification of Cell-Cell Interaction Dynamics in the Tumor Microenvironment.

The three-dimensional (3D) tumor microenvironment (TME) comprises multiple interacting cell types that critically impact tumor pathology and therapeutic response. Efficient 3D imaging assays and analysis tools could facilitate profiling and quantifying distinctive cell-cell interaction dynamics in the TMEs of a wide spectrum of human cancers. Here, we developed a 3D live-cell imaging assay using confocal microscopy of patient-derived tumor organoids and a software tool, SiQ-3D (single-cell image quantifier for 3D), that optimizes deep learning (DL)-based 3D image segmentation, single-cell phenotype classification, and tracking to automatically acquire multidimensional dynamic data for different interacting cell types in the TME. An organoid model of tumor cells interacting with natural killer cells was used to demonstrate the effectiveness of the 3D imaging assay to reveal immuno-oncology dynamics as well as the accuracy and efficiency of SiQ-3D to extract quantitative data from large 3D image datasets. SiQ-3D is Python-based, publicly available, and customizable to analyze data from both in vitro and in vivo 3D imaging. The DL-based 3D imaging analysis pipeline can be employed to study not only tumor interaction dynamics with diverse cell types in the TME but also various cell-cell interactions involved in other tissue/organ physiology and pathology. SIGNIFICANCE: A 3D single-cell imaging pipeline that quantifies cancer cell interaction dynamics with other TME cell types using primary patient-derived samples can elucidate how cell-cell interactions impact tumor behavior and treatment responses.

Effects and mechanism of ultrasound treatment on Chironomus kiiensis eggs.

Chironomids are abundant insects in freshwater ecosystems and lay in still or slow-moving water. The walls of sedimentation tanks in drinking water treatment plants (DWTP) provide such laying habitat, which can lead to larval outbreaks in plant effluent. While chironomid larvae are often associated with poor hygiene, effective methods to control outbreaks are needed. Here, we assessed the effect of ultrasound treatment on Chironomus kiiensis' eggs. The mortality rate of eggs was examined after ultrasound treatment, and the protein content (heat shock protein 70 and hemoglobin) and enzymatic activities of acetylcholinesterase, cytochrome P450, and glutathione S-transferases involved in the ultrasound-induced stress response were analyzed before and after treatment. COMSOL software was also used to examine the characteristics of the ultrasonic field, including frequency, power, exposure distance, and time. Higher egg mortality was observed at lower frequencies. At 28 kHz, 450 W, 15-mm exposure distance, and 75-s exposure time, 72.4% of eggs showed apoptosis after exposure. At higher frequencies (68 kHz), mortality decreased to 50.9%. Exposure time and distance also significantly affected egg mortality. From the geometric models, it could be seen that C. kiiensis' eggs sustained much greater acoustic pressure (2379 Pa) with 28-kHz exposure than that with 68-kHz exposure (422 Pa); however, the propagation distance was greater at the higher frequency. The hydraulic shear force effect of the ultrasonic radiation appeared to be the primary factor in egg mortality. We expected that array of ultrasonic transducers embedded in the walls of water treatment plants could be effective in killing Chironomus' eggs and highlight the potential for ultrasound as an effective treatment for the prevention of Chironomus outbreaks in treatment plant effluents.

Effects of ultrasound on invasive golden mussel Limnoperna fortunei mortality and tissue lesions.

Biofouling by the invasive golden mussel Limnoperna fortunei deleteriously affects artificial water systems, but few effective, environmentally friendly antifouling strategies exist. We propose ultrasound for control of this invasive mussel and report minimum exposure times to kill juveniles and adults at ultrasonic powers ranging 300-600 W from a fixed distance of 8.5 cm. Analysis using a PMA + RT-qPCR assay revealed the formation of tissue lesions in response to ultrasound, with gill tissue more prone to injury than adductor muscle tissue. Shell microstructure determined using scanning electron microscopy (SEM) + energy dispersive X-ray spectroscopy (EDS) is plywood-like, with a thicker shell and increased numbers of prism and nacre layers in adult mussels that provide greater resistance to ultrasound, reducing mortality and tissue lesions. Our results suggest L. fortunei biomass could be effectively reduced by ultrasound, especially for early life-history stages without, or with only immature shells.