Yaqin Tang

INTRODUCTION: Quercetin was recently reported to help protect against osteoarthritis (OA) progression, but the molecular mechanism for that protective affect remains unclear. METHODS: Here, OA model rats were intraperitoneally injected with quercetin, and the severity of cartilage damage in the rats was evaluated by H&E, Safranin O, and Toluidine blue, as well as by using the Osteoarthritis Research Society International (OARSI) Scoring System. Additionally, rat chondrocytes were treated with quercetin and then stimulated with IL-1β. The levels of pro-inflammatory cytokines (IL-1β, IL-18, and TNF-α) were detected by ELISA.Cell apoptosis was evaluated by flow cytometry and Hoechst staining. ROS levels were measured using a DCFH-DA probe. Protein expression was evaluated by Western blotting, immunohistochemical staining, and immunofluorescence. RESULTS: Our data showed that quercetin attenuated the degeneration and erosion of articular cartilage, suppressed inflammation and apoptosis, and downregulated the levels of IRAK1, NLRP3, and caspase-3 expression. In vitro data showed that overexpression of NLRP3 could reverse the suppressive effect of quercetin on IL-1β-induced rat chondrocyte injuries. Importantly, rescue experiments confirmed that quercetin inhibited IL-1β-induced rat chondrocyte injuries in vitro by suppressing the IRAK1/NLRP3 signaling pathway. CONCLUSION: Our study indicated that quercetin inhibits IL-1β-induced inflammation and cartilage degradation by suppressing the IRAK1/NLRP3 signaling pathway.

RNA interference mediated by small interfering RNA (siRNA) provides a powerful tool for gene regulation, and has a broad potential as a promising therapeutic strategy. However, therapeutics based on siRNA have had limited clinical success due to their undesirable pharmacokinetic properties. This study presents pH-sensitive nanoparticles-based siRNA delivery systems (PNSDS), which are positive-charge-free nanocarriers, composed of siRNA chemically crosslinked with multi-armed poly(ethylene glycol) carriers via acid-labile acetal linkers. The unique siRNA crosslinked structure of PNSDS allows it to have minimal cytotoxicity, high siRNA loading efficiency, and a stimulus-responsive property that enables the selective intracellular release of siRNA in response to pH conditions. This study demonstrates that PNSDS can deliver tumor necrosis factor alpha (TNF-α) siRNA into macrophages and induce the efficient down regulation of the targeted gene in complete cell culture media. Moreover, PNSDS with mannose targeting moieties can selectively accumulate in mice liver, induce specific inhibition of macrophage TNF-α expression in vivo, and consequently protect mice from inflammation-induced liver damages. Therefore, this novel siRNA delivering platform would greatly improve the therapeutic potential of RNAi based therapies.

Abstract Protein therapy offers promising prospects for the treatment of various important diseases, thus it is highly desirable to develop a robust carrier that can deliver active proteins into cells. The development of a novel protein delivery platform based on the self‐assembly of multiarmed amphiphilic cyclodextrins (CDEH) is reported. CDEH can self‐assemble into nanoparticles in aqueous solution and achieve superior encapsulation of protein (loading capacity > 30% w/w) simply by mixing with protein solution without introducing any subsequent cumbersome steps that may inactivate proteins. More importantly, CDEH nanovehicles can be easily further modified with various targeting groups based on host–guest complexation. Using saporin as a therapeutic protein, AS1411‐aptamer‐modified CDEH nanovehicles can preferentially accumulate in tumors and efficiently inhibit tumor growth in a MDA‐MB‐231 xenograft mouse model. Moreover, folate‐targeted CDEH nanovehicles can also deliver Cas9 protein and Plk1‐targeting sgRNA into Hela cells, leading to 47.1% gene deletion and 64.1% Plk1 protein reduction in HeLa tumor tissue, thereby effectively suppressing the tumor progression. All these results indicate the potential of targeted CDEH nanovehicles in intracellular protein delivery for improving protein therapeutics.

Toxoplasmosis, caused by an obligate intracellular parasite Toxoplasma gondii, is one of the most prevalent zoonoses worldwide. Treatments for this disease by traditional drugs have shown numerous side effects, thus effective alternative anti-Toxoplasma strategies or drugs are urgently needed. In this study, a novel spider peptide, XYP1, was identified from the cDNA library of the venom gland of the spider Lycosa coelestis. Our results showed that XYP1 has potent anti-Toxoplasma activity in vitro and in vivo. Specifically, treatment with XYP1 significantly inhibited the viability, invasion and proliferation of tachyzoites with low cytotoxicity (IC50 = 38.79 μΜ) on human host cells, and increased the survival rate of mice acutely infected with T. gondii. Next, scanning electron microscopy, transmission electron microscopy and RNA sequencing were employed to further explore the functional mechanism of XYP1, and the results indicated that XYP1 causes membrane perforation, swelling and disruption of tachyzoites, which could be closely associated with differential expression of several membrane-associated proteins including HSP29. In conclusion, XYP1 may be a promising new drug candidate for the treatment of toxoplasmosis.