[Applying Chitosan-Modified Nanoemulsion in Nasal Vaccine Delivery].

OBJECTIVE: To prepare a chitosan-modified cationic nanoemulsion that could be used to prolong the residence time of nasal vaccines in the nasal cavity and improve the cellular uptake efficiency so as to enhance the immune efficacy of nasal vaccines. METHODS: A nanoemulsion-based vaccine coated with chitosan was prepared, and the particle size, potential, antigen encapsulation efficiency, stability as well as cytotoxicity were examined. The uptake efficiency of vaccine on different cells and the residence time of vaccine in the nasal cavity were measured. Finally, nasal vaccine was administered on mice and the antibody levels in the serum and in the nasal lavage fluids of the immunized mice were examined. RESULTS: The nanoemulsion-based vaccine had an average particle size of (167.2±0.75) nm, a polydispersity index (PDI) of 0.21±0.01, and an average potential of (13.7±0.85) mV. The encapsulation efficiency of antigen was 92.7%. The nanoemulsion-based vaccine had good stability and did not show obvious cytotoxicity in Madin-Darby canine kidney (MDCK) epithelial cells. The vaccine demonstrated relatively high cellular uptake of antigens on DC2.4 and MDCK cells at (49.7±3.45)% and (59.7±2.19)%, respectively. Besides, the cationic nanoemulsion also significantly increased the residence time of the antigen, and a considerable amount of nanoemulsion-based vaccine was found remaining in the nasal cavity 60 minutes after administration. Compared with free antigen and the nanoemulsion without chitosan modification, the chitosan-modified nanoemulsion vaccine induced higher systemic and mucosal antibody levels in mice after nasal immunization ( P<0.01). CONCLUSION: The chitosan-modified nanoemulsion vaccine prepared in the study can enhance the immune efficacy of nasal vaccines, showing great potential to be used as a delivery carrier for nasal vaccines.

Establishment of BALB/C mouse models of influenza A H1N1 aerosol inhalation.

Influenza A (H1N1) is a rapidly spreading acute respiratory illness that remains a worldwide burden on public health. To simulate natural infection routes, BALB/C mice were challenged with the H1N1 virus by aerosol and intranasal instillation routes. We compared the weight change and survival of the mice for 14 consecutive days after infection. The infected mice were euthanized at days 3, 5, 7, and 9 to perform necropsies, lung pathological analyses, viral titers measurement, and lung cytokines examination. The aerosol-treated mice showed clinical symptoms on day 4, obvious lung lesions on day 5, rapid weight loss on day 7, peak virus replication in the lungs on days 7 to 9, and bronchial epithelial hyperplasia on day 9. However, after intranasal instillation, the mice exhibited clinical signs on day 2, rapid weight loss and obvious lung lesions on day 3, and peak virus replication in the lungs on days 3 to 5; no bronchial epithelial hyperplasia was detected. High levels of proinflammatory cytokines and chemokines were detected in the lungs of infected mice by both two routes. Disease and lung lesion progressions were slower in the mice that inhaled H1N1-containing aerosols than in those treated by intranasal instillation, and lung lesions were homogeneous in the aerosol group and heterogeneous in the intranasal group. In this study, BALB/C mouse models of H1N1 virus aerosol inhalation were successfully established and compared with mouse models of intranasal inoculation, aerosol mouse models had an infection route and lung pathology characteristics that more closely resembled those observed in humans.

miRNAs expression profile in bast of ramie elongation phase and cell wall thickening and end wall dissolving phase.

MicroRNAs (miRNAs) are 20-24 nucleotide long non-coding RNAs that play critical regulatory roles during plant development, organ morphogenesis, and cell fate determination and differentiation. In this study, miRNA microarray chips were used to explore the expression profile of ramie miRNAs between the bast of fiber elongation phase and those of cell wall thickening and end wall dissolving phase. There are 150 and 148 credible miRNAs in the bast of fiber elongation phase and cell wall thickening and end wall dissolving phase, respectively. These miRNAs distributed in 27 species and mainly concentrated in nine species. Analysis showed that 51 miRNAs were differentially expressed: 27 up-regulated (miR166, miR172, miR396, miR482, miR894 and miR2911 families) and 24 down-regulated (miR156, miR159, miR164, miR319 and miR1450 families) in the bast of fiber elongation phase compared with the bast of cell wall thickening and end wall dissolving phase. To further confirm our results, we examined the expression of three miRNAs (zma-miR172b*, pvu-miR482 and vvi-172a) by quantitative real-time reverse transcriptase-PCR. Our results will provide a molecular basis for future research miRNA function on ramie genetics and breeding.

Biomimetic nanodecoys deliver cholesterol-modified heteroduplex oligonucleotide to target dopaminergic neurons for the treatment of Parkinson's disease.

Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by the accumulation of α-synuclein (α-syn) aggregates called Lewy bodies leading to the gradual loss of dopaminergic (DA) neurons in the substantia nigra. Although α-syn expression can be attenuated by antisense oligonucleotides (ASOs) and heteroduplex oligonucleotide (HDO) by intracerebroventricular (ICV) injection, the challenge to peripheral targeted delivery of oligonucleotide safely and effectively into DA neurons remains unresolved. Here, we designed a new DNA/DNA double-stranded (complementary DNA, coDNA) molecule with cholesterol conjugation (Chol-HDO (coDNA)) based on an α-syn-ASO sequence and evaluated its silence efficiency. Further, Chol-HDO@LMNPs, Chol-HDO-loaded, cerebrovascular endothelial cell membrane with DSPE-PEG2000-levodopa modification (L-DOPA-CECm)-coated nanoparticles (NPs), were developed for the targeted treatment of PD by tail intravenous injection. CECm facilitated the blood-brain barrier (BBB) penetration of NPs, together with cholesterol escaped from reticuloendothelial system uptake, as well as L-DOPA was decarboxylated into dopamine which promoted the NPs toward the PD site for DA neuron regeneration. The behavioral tests demonstrated that the nanodecoys improved the efficacy of HDO on PD mice. These findings provide insights into the development of biomimetic nanodecoys loading HDO for precise therapy of PD. STATEMENT OF SIGNIFICANCE: The accumulation of α-synuclein (α-syn) aggregates is a hallmark of PD. Our previous study designed a specific antisense oligonucleotide (ASO) targeting human SNCA, but the traumatic intracerebroventricular (ICV) is not conducive to clinical application. Here, we further optimize the ASO by creating a DNA/DNA double-stranded molecule with cholesterol-conjugated, named Chol-HDO (coDNA), and develop a DA-targeted biomimetic nanodecoy Chol-HDO@LMNPs by engineering cerebrovascular endothelial cells membranes (CECm) with DSPE-PEG2000 and L-DOPA. The in vivo results demonstrated that tail vein injection of Chol-HDO@LMNPs could target DA neurons in the brain and ameliorate motor deficits in a PD mouse model. This investigation provides a promising peripheral delivery platform of L-DOPA-CECm nanodecoy loaded with a new Chol-HDO (coDNA) targeting DA neurons in PD therapy.

Nonviral delivery systems for antisense oligonucleotide therapeutics.

Antisense oligonucleotides (ASOs) are an important tool for the treatment of many genetic disorders. However, similar to other gene drugs, vectors are often required to protect them from degradation and clearance, and to accomplish their transport in vivo. Compared with viral vectors, artificial nonviral nanoparticles have a variety of design, synthesis, and formulation possibilities that can be selected to accomplish protection and delivery for specific applications, and they have served critical therapeutic purposes in animal model research and clinical applications, allowing safe and efficient gene delivery processes into the target cells. We believe that as new ASO drugs develop, the exploration for corresponding nonviral vectors is inevitable. Intensive development of nonviral vectors with improved delivery strategies based on specific targets can continue to expand the value of ASO therapeutic approaches. Here, we provide an overview of current nonviral delivery strategies, including ASOs modifications, action mechanisms, and multi-carrier methods, which aim to address the irreplaceable role of nonviral vectors in the progressive development of ASOs delivery.

Apoptotic bodies for advanced drug delivery and therapy.

Extracellular vesicles (EVs) have emerged as promising candidates for multiple biomedical applications. Major types of EVs include exosomes, microvesicles, and apoptotic bodies (ABs). ABs are conferred most properties from parent cells in the final stages of apoptosis. A wide variety of sources and stable morphological features are endowed to ABs by the rigorous apoptotic program. ABs accommodate more functional biomolecules by relying on the larger volume and maintaining their naturalness in circulation. The predominant body surface ratio of ABs facilitates their recognition by recipient cells and is advantageous for interactions with microenvironments. ABs can modulate and alleviate symptoms of numerous diseases for their origins, circulation, and high biocompatibility. In addition, ABs have been emerging in disease diagnosis, immunotherapy, regenerative therapy, and drug delivery. Here, we aim to present a thorough discussion on current knowledge about ABs. Of particular interest, we will summarize the application of AB-based strategies for diagnosis and disease therapy. Perspectives for the development of ABs in biomedical applications are highlighted.

The characteristics of hDPP4 transgenic mice subjected to aerosol MERS coronavirus infection via an animal nose-only exposure device.

BACKGROUND: Middle East respiratory syndrome coronavirus (MERS-CoV), which is not fully understood in regard to certain transmission routes and pathogenesis and lacks specific therapeutics and vaccines, poses a global threat to public health. METHODS: To simulate the clinical aerosol transmission route, hDPP4 transgenic mice were infected with MERS-CoV by an animal nose-only exposure device and compared with instillation-inoculated mice. The challenged mice were observed for 14 consecutive days and necropsied on days 3, 5, 7, and 9 to analyze viral load, histopathology, viral antigen distribution, and cytokines in tissues. RESULTS: MERS-CoV aerosol-infected mice with an incubation period of 5-7 days showed weight loss on days 7-11, obvious lung lesions on day 7, high viral loads in the lungs on days 3-9 and in the brain on days 7-9, and 60% survival. MERS-CoV instillation-inoculated mice exhibited clinical signs on day 1, obvious lung lesions on days 3-5, continuous weight loss, 0% survival by day 5, and high viral loads in the lungs and brain on days 3-5. Viral antigen and high levels of proinflammatory cytokines and chemokines were detected in the aerosol and instillation groups. Disease, lung lesion, and viral replication progressions were slower in the MERS-CoV aerosol-infected mice than in the MERS-CoV instillation-inoculated mice. CONCLUSION: hDPP4 transgenic mice were successfully infected with MERS-CoV aerosols via an animal nose-only exposure device, and aerosol- and instillation-infected mice simulated the clinical symptoms of moderate diffuse interstitial pneumonia. However, the transgenic mice exposed to aerosol MERS-CoV developed disease and lung pathology progressions that more closely resembled those observed in humans.