Highlights d The mammalian receptor Mrgprb2 and MRGPRX2 can detect bacterial QSMs d QSM detection by Mrgprb2 and MRGPRX2 in mast cells elicits antibacterial mediator release d Mrgprb2 recognition of QSMs is critical for an effective immune response to bacteria d Pharmacologic activation of Mrgprb2 and MRGPRX2 enhances bacterial clearance

It has been suggested that combined effect of natural products may improve the treatment effectiveness in combating proliferation of cancer cells. Here, we examined the combined anticancer activities of compounds of three natural origin including baicalein, curcumin, and resveratrol with chemotherapy drug paclitaxel respectively, which showed that combination of paclitaxel with curcumin exhibited synergistic growth inhibition and induced significant apoptosis in MCF-7 cell lines. Treatment of MCF-7 cell lines with paclitaxel and curcumin induced the apoptosis of regulatory protein Bcl-2 but decreased Bax expression. In addition, simultaneous treatment with paclitaxel and curcumin strongly inhibited paclitaxel-induced activities of EGFR signaling. Furthermore, the combination of paclitaxel and curcumin exerted increased anti-tumor efficacy on mouse models. Overall, our data described the promising therapeutic potential and underlying mechanisms of combining paclitaxel with curcumin in treating breast cancer.

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Background The novel coronavirus disease (2019-nCoV) has been affecting global health since the end of 2019 and there is no sign that the epidemic is abating . The major issue for controlling the infectious is lacking efficient prevention and therapeutic approaches. Chloroquine (CQ) and Hydroxychloroquine (HCQ) have been reported to treat the disease, but the underlying mechanism remains controversial. Purpose The objective of this study is to investigate whether CQ and HCQ could be ACE2 blockers and used to inhibit 2019-nCoV virus infection. Methods In our study, we used CCK-8 staining, flow cytometry and immunofluorescent staining to evaluate the toxicity and autophagy of CQ and HCQ, respectively, on ACE2 high-expressing HEK293T cells (ACE2 h cells). We further analyzed the binding character of CQ and HCQ to ACE2 by molecular docking and surface plasmon resonance (SPR) assays, 2019-nCoV spike pseudotyped virus was also used to observe the viropexis effect of CQ and HCQ in ACE2 h cells. Results Results showed that HCQ is slightly more toxic to ACE2 h cells than CQ. Both CQ and HCQ could bind to ACE2 with K D = (7.31 ± 0.62) e −7 M and (4.82 ± 0.87) e −7 M, respectively. They exhibit equivalent suppression effect for the entrance of 2019-nCoV spike pseudotyped virus into ACE2 h cells. Conclusions CQ and HCQ both inhibit the entrance 2019-nCoV into cells by blocking the binding of the virus with ACE2. Our findings provide novel insights into the molecular mechanism of CQ and HCQ treatment effect on virus infection.

Coronavirus Disease 2019 (COVID-19) cases and deaths are still rising worldwide, there is currently no effective treatment for severe inflammation and acute lung injury caused by new coronavirus (SARS-COV-2) infection. Therapies to prevent or treat COVID-19, including antiviral drug and several vaccines, are still being development. Human angiotensin-converting enzyme 2 (ACE2), expressing in lung, has been confirmed to be a receptor for SARS-COV-2 infection, interventions for attachment of spike protein of SARS-CoV-2 to ACE2 may be a potential approach to prevent viral infections and it is considered as a potential target for drug development. In this study, we observed that seabuckthorn and its flavonoid compounds quercetin and isorhamnetin were shown strong retention to ACE2 overexpression HEK293 (ACE2 h ) cells by CMC analysis. Based on drug receptor interaction analysis and viral entry studies in vitro, we evaluated the interaction of two flavonoid compounds and ACE2 as well as the inhibitory effect of the two compounds on viral entry. Surface plasmon resonance assay proved the effect that isorhamnetin bound to the ACE2, and its affinity (KD value) was at the micromolar level, that was, 2.51 ± 0.68 μM. Viral entry studies in vitro indicated that isorhamnetin inhibited SARS-CoV-2 spike pseudotyped virus entering ACE2 h cells. Based on promising in vitro results, we proposed isorhamnetin to be a potential therapeutic candidate compound against COVID-19.