RAB39B is located on the X chromosome and encodes the RAB39B protein that belongs to the RAB family. Mutations in RAB39B are known to be associated with X-linked intellectual disability (XLID), Parkinson’s disease, and autism. However, the patho/physiological functions of RAB39B remain largely unknown. In the present study, we established Rab39b knockout (KO) mice, which exhibited overall normal birth rate and morphologies as wild type mice. However, Rab39b deficiency led to reduced anxiety and impaired learning and memory in 2 months old mice. Deletion of Rab39b resulted in impairments of synaptic structures and functions, with reductions in NMDA receptors in the postsynaptic density (PSD). RAB39B deficiency also compromised autophagic flux at basal level, which could be overridden by rapamycin-induced autophagy activation. Further, treatment with rapamycin partially rescued impaired memory and synaptic plasticity in Rab39b KO mice, without affecting the PSD distribution of NMDA receptors. Together, these results suggest that RAB39B plays an important role in regulating both autophagy and synapse formation, and that targeting autophagy may have potential for treating XLID caused by RAB39B loss-of-function mutations.

BackgroundLeading to more and more deaths and disabilities, stroke has become a serious threat to human health. What’s more, few effective drugs are available in clinic till now.ResultsIn this research, we prepared a novel neuroprotective nanoformation (OEA–SPC NPs) via the combination of the nanoparticle drug delivery system with the endogenous N-oleoylethanolamine (OEA). By forming hydrogen bond between OEA and the carrier—soybean phosphatidylcholine (SPC), the form of OEA was turned into amorphus state when loading to the nanoparticles, which greatly improved its bioavailability. Then the following systematic experiments revealed the efficient neuroprotective effect of OEA–SPC NPs in vivo. Compared with the MCAO group, the cerebral infarct volume was reduced by 81.1%, and the edema degree by 78.4% via the oral administration of OEA–SPC NPs. And the neurological deficit scores illustrated that the MCAO rats treated with OEA–SPC NPs exhibited significantly less neurological dysfunction. The Morris water maze test indicated that the spatial learning and memory of cerebral ischemia model rats were almost recovered to the normal level. Besides, the OEA–SPC NPs could inhibit the inflammation of reperfusion to a very slight level.ConclusionsThese results suggest that the OEA–SPC NPs have a great chance to be a potential anti-stroke formation for clinic application and actually bring hope to thousands of stroke patients.Electronic supplementary materialThe online version of this article (10.1186/s12951-019-0442-x) contains supplementary material, which is available to authorized users.

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Introduction:The livertaxis of glycyrrhizic acid-conjugated bovine serum albumin (GL-BSA) has been reported in the literature. Now, in this paper, we describe a novel type of drug-targeted delivery system containing 10-hydroxycamptothecin (HCPT) with liver tumor targeting. Methods: First, GL was coupled to BSA then HCPT was encapsulated in GL-BSA by highpressure homogenization emulsification. In the experimental design, the influencing variables on particle size and drug loading efficiency were determined to be BSA concentration, volume ratio of water to organic phase, and speed and speed duration of homogenization as well as homogenization pressure and the number of times homogenized at certain pressures. Particle size plays an important role in screening optimal conditions of nanoparticles preparation. Characteristics of 10-hydroxycamptothecin-loaded glycyrrhizic acid-conjugated bovine serum albumin nanoparticles (GL-BSA-HCPT-NPs), such as the drug encapsulation efficiency, drug loading efficiency, and GL-BSA content were studied. In addition, the morphology of the nanoparticles (NPs) and weight loss rate were determined and Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, and thermal analysis performed. Results: The average particle size of the sample NPs prepared under optimal conditions was 157.5 nm and the zeta potential was −22.51 ± 0.78 mV; the drug encapsulation efficiency and drug loading efficiency were 93.7% and 10.9%, respectively. The amount of GL coupling to BSA was 98.26 µg/mg. Through physical property study of the samples, we determined that the HCPT had been successfully wrapped in GL-BSA. In vitro drug-release study showed that the nanoparticles could release the drug slowly and continuously. Hemolysis testing showed the safety of GL-BSA as a novel drug delivery system. The targeting properties of GL-BSA-HCPT-NPs were studied in an in vitro cell uptake study and cell proliferation assay. Cells incubated with GL-BSA-HCPT-NPs and labeled with fluorescein isothiocyanate showed more extensive fluorescence spots and stronger fluorescence intensity than samples without GL conjugation. MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to determine the inhibitory rate of the samples. It was found that the inhibitory rate of GL-BSA-HCPT-NPs develops as concentration rises. Further, the inhibitory rate of GL-BSA-HCPT-NPs was higher at the same concentration and had a lower half maximal inhibitory concentration value than the other samples. The half maximal inhibitory concentration values of GL-BSA-HCPT-NPs, BSA-HCPT-NPs, and HCPT sodium were 0.78 ± 0.015, 1.62 ± 0.039, and 7.93 ± 0.255 µg/ mL, respectively. Conclusion:The results of this study show GL-BSA-HCPT to be a promising new vehicle for hepatocellular carcinoma-targeting therapy.