A facile turn-on chemiluminescence probe for sensitive imaging on aminopeptidase N activity.

Aminopeptidase N, as a target for drug discovery, shows marked relationships with many diseases, especially liver injury and cancer. Here, we explored a chemiluminescence (CL) probe for sensing APN by tethering the APN-specific substrate group to the ortho-acrylated phenoxy-dioxetane scaffold. In this way, two CL probes (APN-CL and BAPN-CL) were designed with noncapped leucine and butoxy-carbonyl capped leucine as the protecting group to preserve the chemiexcitation energy. The uncovered leucine was demonstrated to be essential for detection of APN activity by comparing the CL intensity of two CL probes. Probe APN-CL was turned on upon APN cleavage, resulting in a high chemiluminescent emission, whereas the chemiexcitation energy of probe BAPN-CL was still restrained even with the high-level APN. The result was further elucidated by molecular docking simulations. Probe APN-CL exhibited a fast response and high sensitivity with a detection limit of 0.068 U/L, and an excellent specificity for the discrimination of APN from biological ions, small molecules, and other proteases commonly found in living system. By virtue of good stability and cell viability, probe APN-CL imaged abnormal levels of APN in tumour cells and tumour-bearing mice. Moreover, this probe APN-CL could be easily used to evaluate APN inhibitors and APN levels in plasma samples from 20 patients. Overall, as a facile and cost-effective probe, APN-CL will be a promising alternative in the early diagnosis of pathologies and for cost-effective screening of inhibitors.

An activatable chemiluminescence probe based on phenoxy-dioxetane scaffold for biothiol imaging in living systems.

Quantification of biothiols in living systems is essential to understand their biological applications. Here, we developed two activatable chemiluminescence probes (SHCL and NCCL) and investigated their utility in the bioimaging of intracellular biothiols by directly tethering 2,4-dinitrobenzenesulfonyl to the hydroxyl group of phenoxy-dioxetane. The design of these two probes differed in substituents of phenol-dioxetane, i.e., SHCL contained the ortho chlorine, whereas NCCL had the para hydroxymethyl. Upon glutathione (GSH) cleavage, both probes emitted significantly "turn-on" chemiluminescent signals. However, the chemiluminescence intensity based on NCCL declined with increasing GSH level above 5 mM, while SHCL exhibited much higher chemiluminescent intensity and a wider concentration range (0.5 µM-50 mM), which was much more suitable for sensing endogenous biothiols. We further demonstrated that chlorine substitution in SHCL played an important role in bioimaging owing to the halogen effect, providing a lower pKa value and significant enhancement of the chemiluminescent emission. SHCL imaged the biothiols effectively in tumor cells and tumor-bearing mice. Additionally, this novel chemiluminescence probe can be easily used to evaluate the in vitro activity of acetylcholinesterase. Overall, we anticipate that SHCL may provide a facile and intuitive tool for studying the role of biothiols in diseases.

LncRNA GAS5 is upregulated in polycystic ovary syndrome and regulates cell apoptosis and the expression of IL-6.

BACKGROUND: GAS5 contains a hormone response element that can induce cell apoptosis in breast cancer. It is known that cell apoptosis and hormone response play crucial roles in polycystic ovary syndrome (PCOS), indicating the potential involvement of GAS5 in PCOS. This study was performed to investigate the potential involvement of GAS5 and IL-6 (a critical player in PCOS) in PCOS. METHODS: Research subjects of this study included 60 PCOS patients and 60 healthy controls. The expression levels of GAS5 and IL-6 in plasma of both patients and controls were measured by qPCR and ELISA, respectively. Cell transfections were performed to analyze the interaction between GAS5 and IL-6. Cell apoptosis was analyzed by cell apoptosis assay. RESULTS: GAS5 was upregulated in plasma of PCOS patients. The expression levels of GAS5 were positively correlated with the expression levels of IL-6. Altered expression levels of GAS5 and IL-6 distinguished PCOS patients from healthy controls. In cells of a granulosa-like tumor cell line (KGN), overexpression of GAS5 led to upregulated IL-6, while silencing of GAS5 played an opposite role. Cell apoptosis analysis showed that overexpression of GAS5 significantly decreased apoptosis rate of KGN cells. Silencing of GAS5 increased the rate of KGN cell apoptosis. CONCLUSIONS: GAS5 is upregulated in PCOS and regulates cell apoptosis and the expression of IL-6.

Conservation of genetic diversity hotspots of the high-valued relic yellowhorn (Xanthoceras sorbifolium) considering climate change predictions.

Genetic structure and major climate factors may contribute to the distribution of genetic diversity of a highly valued oil tree species Xanthoceras sorbifolium (yellowhorn). Long-term over utilization along with climate change is affecting the viability of yellowhorn wild populations. To preserve the species known and unknown valuable gene pools, the identification of genetic diversity "hotspots" is a prerequisite for their consideration as in situ conservation high priority. Chloroplast DNA (cpDNA) diversity was high among 38 natural populations (H d = 0.717, K = 4.616, Tajmas' D = -0.22) and characterized by high genetic divergence (F ST = 0.765) and relatively low gene flow (N m = 0.03), indicating populations isolation reflecting the species' habitat fragmentation and inbreeding depression. Six out of the studied 38 populations are defined as genetic diversity "hotspots." The number and geographic direction of cpDNA mutation steps supported the species southwest to northeast migration history. Climatic factors such as extreme minimum temperature over 30 years indicated that the identified genetic "hotspots" are expected to experience 5°C temperature increase in next following 50 years. The results identified vulnerable genetic diversity "hotspots" and provided fundamental information for the species' future conservation and breeding activities under the anticipated climate change. More specifically, the role of breeding as a component of a gene resource management strategy aimed at fulfilling both utilization and conservation goals.