No abstract

Background Heart failure is a growing epidemic and a typical aspect of heart failure pathophysiology is altered calcium transients. Normal cardiac calcium transients are initiated by Cav1.2 channels at cardiac T-tubules. BIN1 is a membrane scaffolding protein that causes Cav1.2 to traffic to T-tubules in healthy hearts. The mechanisms of Cav1.2 trafficking in heart failure are not known. Objective To study BIN1 expression and its effect on Cav1.2 trafficking in failing hearts. Methods Intact myocardium and freshly isolated cardiomyocytes from non-failing and end-stage failing human hearts were used to study BIN1 expression and Cav1.2 localization. To confirm Cav1.2 surface expression dependence on BIN1, patch clamp recordings were performed of Cav1.2 current in cell lines with and without trafficking competent BIN1. Also, in adult mouse cardiomyocytes, surface Cav1.2 and calcium transients were studied after shRNA mediated knockdown of BIN1. For a functional readout in intact heart, calcium transients and cardiac contractility were analyzed in a zebrafish model with morpholino mediated knockdown of BIN1. Results BIN1 expression is significantly decreased in failing cardiomyocytes at both mRNA (30% down) and protein (36% down) levels. Peripheral Cav1.2 is reduced 42% by imaging and biochemical T-tubule fraction of Cav1.2 is reduced 68%. Total calcium current is reduced 41% in a cell line expressing non-trafficking BIN1 mutant. In mouse cardiomyocytes, BIN1 knockdown decreases surface Cav1.2 and impairs calcium transients. In zebrafish hearts, BIN1 knockdown causes a 75% reduction in calcium transients and severe ventricular contractile dysfunction. Conclusions The data indicate that BIN1 is significantly reduced in human heart failure, and this reduction impairs Cav1.2 trafficking, calcium transients, and contractility.

Living cells can change their intramembranous temperature during cell activities such as division, gene expression, enzyme reaction, and metabolism [1,2]. Moreover, under external stimuli, such as drugs or other signals, cells may quickly change their metabolic activities, leading to acute variation of intracellular temperatures from the normal state [3,4]. However, such temperature change inside cells is usually at a small scale and is of transient nature due to the thermo-influence by the extracellular environment, rendering it rather difficult to measure using the conventional temperature detection methods. Thus, a more precise and faster-response thermometer is needed to measure single-cell temperature changes in real time, which may constitute a new layer of cellular information for studies of cellular signaling, and even clinical diagnosis and therapy.Fluorescent nanogel has been previously applied to detect changes in intracellular temperature [4]. Cells were first allowed to take up a fluorescence material and the average intracellular temperature change under a certain treatment was then determined through measuring the distinct fluorescent light intensity before and after the treatment. Such a fluorescent nanogel-based method has a number of disadvantages, including potential toxicity to cells, limit of measurement resolution (generally in the range of 0.29 °C-0.50 °C), and limit of time-scale resolution (at the scale of minutes).Thermocouple (TC) is widely used in settings that require detection of temperature changes. The TC-based detection method has a number of advantages, including the capacity for achieving high precision and rapid response. To adapt the TC method for temperature measurement at the single-cell level, one would need to develop a micro-sized TC probe (at sub-micrometer scale). The thin film method is a common approach to producing two-dimensional micro-or even nano-TCs for use in electronics industry [5]. However, such two-dimensional TCs that rely on the support of silicon chips cannot be readily used for measuring intracellular temperature. In this report, we designed a novel TC device for detecting intracellular temperature ( Figure 1A and 1B). Briefly, our TC probe is made of a sandwich structure consisting of the tungsten (W) substrate, an insulating layer made of polyurethane (PU; except at the tip), and a platinum (Pt) film (Supplementary information, Figure S1). We produced two types of TC probes, with different thickness of the Pt film (50 nm and 100 nm). In a calibration experiment with these two types of probes, we found that the 100 nm probe produced a temperature-thermoelectricity curve that showed an almost perfect match with the standard curve produced by a regular macro-sized TC, while the readings from the 50 nm probe showed deviations from the standard curve ( Figure 1B and 1C and Supplementary information, Figure S2). This result is consistent with earlier reports that when the thickness of the Pt film decreases beyond the 100 nm range, it will affect the resulti...

A critical question in natural product-based drug discovery is how to translate the product into drug-like molecules with optimal pharmacological properties. The generation of natural product-inspired scaffold diversity is an effective but challenging strategy to investigate the broader chemical space and identify promising drug leads. Extending our efforts to the natural product evodiamine, a diverse library containing 11 evodiamine-inspired novel scaffolds and their derivatives were designed and synthesized. Most of them showed good to excellent antitumor activity against various human cancer cell lines. In particular, 3-chloro-10-hydroxyl thio-evodiamine (66c) showed excellent in vitro and in vivo antitumor efficacy with good tolerability and low toxicity. Antitumor mechanism and target profiling studies indicate that compound 66c is the first-in-class triple topoisomerase I/topoisomerase II/tubulin inhibitor. Overall, this study provided an effective strategy for natural product-based drug discovery.

A rapid, on-site, and accurate SARS-CoV-2 detection method is crucial for the prevention and control of the COVID-19 epidemic. However, such an ideal screening technology has not yet been developed for the diagnosis of SARS-CoV-2. Here, we have developed a deep learning-based surface-enhanced Raman spectroscopy technique for the sensitive, rapid, and on-site detection of the SARS-CoV-2 antigen in the throat swabs or sputum from 30 confirmed COVID-19 patients. A Raman database based on the spike protein of SARS-CoV-2 was established from experiments and theoretical calculations. The corresponding biochemical foundation for this method is also discussed. The deep learning model could predict the SARS-CoV-2 antigen with an identification accuracy of 87.7%. These results suggested that this method has great potential for the diagnosis, monitoring, and control of SARS-CoV-2 worldwide.