Lanlan Liu

Large-Scale Self-Assembly of 3D Flower-like Hierarchical Ni/Co-LDHs Microspheres for High-Performance Flexible Asymmetric Supercapacitors

In this study, a facile and inexpensive and self-assembled strategy to massively fabricate Ni/Co layered double hydroxides (LDHs) is developed under mild reaction conditions (55 °C). The resulting composite material displays a special three-dimensional hierarchical microsphere structure with well-defined flower-like configuration. The fabrication mechanism can be ascribed to stepwise and regular reaction process of nanoparticles and nanosheets gradually growing to nanopetals and then assembling into flower-like microspheres, based on the systematically investigation of various reaction factors including the Ni:Co feeding ratio, the reaction time and the initial pH-value. Because of its large surface, ultrathin feature and synergetic results of this Ni/Co LDHs nanosheets (20 nm), these Ni/Co-LDHs microspheres deliver an excellent capacitance value about 2228 F·g(-1) (1 A·g(-1)). An all-solid-state flexible asymmetric supercapacitor is designed and assembled by exploiting this Ni/Co-LDHs as the positive materials, which exhibits energy density of 165.51 Wh·kg(1-) at 1.53 KW·kg(1-). It may have vast potential significance in personal wearable equipment. Moreover, this monolithic design provides a promising approach for large scale fabrication of other LDHs materials.

Bioreducible alginate-poly(ethylenimine) nanogels as an antigen-delivery system robustly enhance vaccine-elicited humoral and cellular immune responses

Although polysaccharide nanogels have emerged as a novel antigen delivery system for vaccine development, whether modulating the redox sensitivity of nanogels could improve vaccine efficacy remains unclear. In the present study, we generated bioreducible cationic alginate-polyethylenimine (PEI) nanogels as a novel vaccine delivery system. Briefly, nanogels were prepared by the electrostatic interaction of negatively charged alginate sodium with branched PEI2k, followed by disulfide cross-linking to generate bioreducible nanogels (AP-SS). The AP-SS nanogels demonstrated great antigen-loading capacity and minimal cytotoxicity. The in vitro study showed that reducible AP-SS nanogels not only facilitated antigen uptake by mouse bone marrow dendritic cells (BMDCs), but also promoted intracellular antigen degradation and cytosolic release. Moreover, AP-SS nanogels significantly enhanced both MHC class I and II antigen presentation by BMDCs. Compared with the non-reducible nanogels, AP-SS nanogels more potently enhanced vaccine-induced antibody production and CD8+ T cell-mediated tumor cell lysis. Hence, the bioreducible alginate-PEI nanogels could serve as a potent adjuvant to improve vaccine-elicited humoral and cellular immune responses.

Cationic polypeptide micelle-based antigen delivery system: A simple and robust adjuvant to improve vaccine efficacy

Modern subunit vaccines with purified or recombinant antigens are important alternatives to the traditional vaccines. However, there remains a big challenge to elicit potent antibody production and CD8 T cell response. Nanoparticle-based antigen delivery systems have emerged as an innovative strategy to improve the efficacy of subunit vaccines. The present study reported self-assembled cationic micelles based on poly(ethylene glycol)-b-poly(L-lysine)-b-poly(L-leucine) (PEG-PLL-PLLeu) hybrid polypeptides as a simple and potent vaccine delivery system. The results showed that the PEG-PLL-PLLeu micelles spontaneously encapsulated OVA antigens with great loading capacity (LC=55%) and stability. More importantly, the polypeptide micelle formulations robustly enhanced vaccine-induced antibody production by 70-90 fold, which could be due to their capability of inducing dendritic cell maturation, enhancing antigen uptake and presentation, as well as promoting germinal center formation. Furthermore, the polypeptide micelles could simultaneously encapsulate OVA and polyriboinosinic: polyribocytidylic acid (PIC), a TLR3 agonist, to synergistically augment tumor specific cytotoxic-T-lymphocyte (CTL) response. Hence, the polypeptide micelle-based antigen delivery system could be a robust adjuvant to enhance vaccine-induced immune responses.

Autophagy mediates avian influenza H5N1 pseudotyped particle-induced lung inflammation through NF-κB and p38 MAPK signaling pathways

Since avian influenza virus H5N1-induced hypercytokemia plays a key role in acute lung injury, understanding its molecular mechanism is highly desirable for discovering therapeutic targets against H5N1 infection. In the present study, we investigated the role of autophagy in H5N1-induced lung inflammation by using H5N1 pseudotyped viral particles (H5N1pps). The results showed that H5N1pps significantly induced autophagy both in A549 human lung epithelial cells and in mouse lung tissues, which was primarily due to hemagglutinin (HA) of H5N1 virus. Blocking autophagy with 3-methyladenine (an autophagy inhibitor) or siRNA knockdown of autophagy-related genes (beclin1 and atg5) dramatically attenuated H5N1pp-induced proinflammatory cytokines and chemokines, such as IL-1β, TNF-α, IL-6, CCL2, and CCL5, both in vitro and in vivo. Autophagy-mediated inflammatory responses involved the activation of NF-κB and p38 MAPK signaling pathways, which required the presence of clathrin but did not rely on p62 or autophagosome-lysosome fusion. On the other hand, the activation of NF-κB also promoted H5N1pp-induced autophagosome formation. These data indicated a positive feedback loop between autophagy and NF-κB signaling cascade, which could exacerbate H5N1pp-induced lung inflammation. Our data demonstrated an essential role of autophagy in H5N1pp-triggered inflammatory responses, and targeting the autophagic pathway could be a promising strategy to treat H5N1 virus-caused lung inflammation.

Noninvasive visualization of respiratory viral infection using bioorthogonal conjugated near-infrared-emitting quantum dots.

Highly pathogenic avian influenza A viruses are emerging pandemic threats in human beings. Monitoring the in vivo dynamics of avian influenza viruses is extremely important for understanding viral pathogenesis and developing antiviral drugs. Although a number of technologies have been applied for tracking viral infection in vivo, most of them are laborious with unsatisfactory detection sensitivity. Herein we labeled avian influenza H5N1 pseudotype virus (H5N1p) with near-infrared (NIR)-emitting QDs by bioorthogonal chemistry. The conjugation of QDs onto H5N1p was highly efficient with superior stability both in vitro and in vivo. Furthermore, QD-labeled H5N1p (QD-H5N1p) demonstrated bright and sustained fluorescent signals in mouse lung tissues, allowing us to visualize respiratory viral infection in a noninvasive and real-time manner. The fluorescence signals of QD-H5N1p in lung were correlated with the severity of virus infection and significantly attenuated by antiviral agents, such as oseltamivir carboxylate and mouse antiserum against H5N1p. The biodistribution of QD-H5N1p in lungs and other organs could be easily quantified by measuring fluorescent signals and cadmium concentration of virus-conjugated QDs in tissues. Hence, virus labeling with NIR QDs provides a simple, reliable, and quantitative strategy for tracking respiratory viral infection and for antiviral drug screening.

Sialic Acid-Targeted Nanovectors with Phenylboronic Acid-Grafted Polyethylenimine Robustly Enhance siRNA-Based Cancer Therapy.

Small interference RNA (siRNA)-based therapy holds great potential for cancer treatment. However, its clinical application remains unsatisfied due to the lack of a safe and effective RNA delivery system. Aberrantly elevated sialyation on cell membrane has been reported as an attractive target for cancer diagnosis and therapy. In this study, phenylboronic acid (PBA) was conjugated onto low molecular weight polyethylenimine (PEI1.8k) to generate amphiphilic PBA-grafted PEI1.8k (PEI-PBA) nanovector, which was designed to facilitate cancer-targeted RNA delivery through the recognition of sialic structures on a cancer cell membrane. PEI-PBA simultaneously encapsulated siRNA to form PEI-PBA/siRNA nanocomplexes with great biocompatibility, serum stability and RNase resistance. The cell culture study showed that PEI-PBA/siRNA dramatically increased siRNA uptake up to 70-90% in several cancer cell lines, which relied on the interaction between PBA and sialic acid on cell membrane. Moreover, the PEI-PBA nanovector effectively promoted the lysosome escape of siRNA, decreasing the expression of target gene Polo-like kinase 1 (PLK-1) in cancer cells. The systemic administration of PEI-PBA/PLK-1 siRNA (PEI-PBA/siPLK1) nanocomplexes not only facilitated tumor-targeted siRNA delivery but also significantly decreased PLK-1 expression in tumors, thereby robustly inducing tumor apoptosis and cell cycle arrest. Additionally, the administration of PEI-PBA/siPLK1 did not cause significant systemic toxicity or immunotoxicity. Hence, sialic acid-targeted PEI-PBA could be a highly efficient and safe nanovector to improve the efficacy of cancer siRNA therapy.

Synergistic Therapy of Doxorubicin and miR-129-5p with Self-Cross-Linked Bioreducible Polypeptide Nanoparticles Reverses Multidrug Resistance in Cancer Cells

Although microRNAs (miRs) are short endogenous noncoding RNAs playing a central role in cancer initiation and progression, their therapeutic potential in overcoming multidrug resistance (MDR) remains unclear. In the present study, we developed self-cross-linked biodegradable poly(ethylene glycol)-b-poly(l-lysine)-b-poly(l-cysteine) (LCss) polypeptide nanoparticles to codeliver DOX and miR-129-5p, which aimed to overcome MDR in cancer cells. The results showed that LCss nanoparticles effectively coencapsulated DOX and miR with great stability, but quickly disassembled and released their payload in a bioreducible environment. The codelivery of miR-129-5p and DOX with LCss (DLCss/miR) significantly increased miR-129-5p expression over 100-fold in MCF-7/ADR cells, which effectively overcame MDR by directly inhibiting P-glycoprotein (P-gp), thereby increasing intracellular DOX accumulation and cytotoxicity in MCF-7/ADR cells. Furthermore, miR-129-5p also partially diminished cyclin-dependent kinase 6 (CDK6), and synergized with DOX to simultaneously decrease S phase and induce G2 phase cell cycle arrest, thereby further enhancing the chemosensitivity of MCF-7/ADR cells. Hence, redox-responsive LCss nanoparticles are potent nanocarrier for combinational drug-miR therapy, which could be a promising strategy to overcome MDR in cancer cells.

Retinal-conjugated pH-sensitive micelles induce tumor senescence for boosting breast cancer chemotherapy

Evoking tumor cellular senescence, an irreversible status of cell growth quiescence, has been recently proposed as a potential strategy to improve the efficacy of cancer treatment. In the current study, all-trans retinal, the precursor of all-trans retinoic acid, was conjugated to dextran via hydrazone bond to generate amphiphilic dextran-retinal (DR) conjugates, which self-assembled into pH-sensitive DR micelles. Our results showed that DR micelles moderately inhibited MCF-7 breast cancer cell growth through inducing p21-associated cellular senescence, which relied on retinoic acid receptors (RARs) and was accompanied by significant G0/G1 cell cycle arrest. Moreover, DR micelles were capable of encapsulating doxorubicin (DOX) to generate DOX-loaded DD micelles, facilitating the uptake and release of DOX in cancer cells. Compared with free DOX, DD micelles more effectively suppressed tumor growth and prolonged survival time of mouse xenograft model through inducing tumor apoptosis and cellular senescence. However, blocking cellular senescence diminished DD-caused apoptosis in MCF-7 cells by 40-50%. Therefore, pH-sensitive DR micelles not only served as a potent platform for DOX delivery, but also enhanced the anti-tumor effect of DOX by inducing tumor cellular senescence. These data reveal a great potential of evoking tumor senescence with retinal-conjugated micelles for boosting breast cancer chemotherapy.

Integrated Nanovaccine with MicroRNA-148a Inhibition Reprograms Tumor-Associated Dendritic Cells by Modulating miR-148a/DNMT1/SOCS1 Axis

Immunosuppressive tumor-associated dendritic cells (TADCs) are potential targets for cancer therapy. However, their poor responsiveness to TLR stimulation is a major obstacle for achieving successful cancer immunotherapy. In the current study, we reported a dysregulated miR-148a/DNA methyltransferase (DNMT)1/suppressor of cytokine signaling (SOCS)1 axis as a unique mechanism for dampened TLR stimulation in TADCs. The results showed that aberrantly elevated miR-148a in bone marrow–derived TADC (BM-TADC) abolished polyinosinic-polycytidylic acid (poly I:C) or LPS-induced dendritic cell maturation through directly suppressing DNMT1 gene, which consequently led to the hypomethylation and upregulation of SOCS1, the suppressor of TLR signaling. In contrast, miR-148a inhibitor (miR-148ai) effectively rescued the expression of DNMT1 and decreased SOCS1 in BM-TADCs, thereby recovering their sensitivity to TLR3 or TLR4 stimulation. To further reprogram TADCs in vivo, miR-148ai was coencapsulated with poly I:C and OVA by cationic polypeptide micelles to generate integrated polypeptide micelle/poly I:C (PMP)/OVA/148ai nanovaccine, which was designed to simultaneously inhibit miR-148a and activate TLR3 signaling in TADCs. The immunization of PMP/OVA/148ai nanovaccine not only effectively modulated the miR-148a/DNMT1/SOCS1 axis in the spleen, but also significantly increased mature dendritic cells both in the spleen and in tumor microenvironment. Moreover, PMP/OVA/148ai ameliorated tumor immunosuppression through reducing regulatory T cells and myeloid-derived suppressor cells, thereby leading to potent anticancer immune responses and robust tumor regression with prolonged survival. This study proposes a nanovaccine-based immunogene therapy with the integration of miR-148a inhibition and TLR3 stimulation as a novel therapeutic approach to boost anticancer immunity by reprogramming TADCs in vivo.

Lymphatic-targeted cationic liposomes: A robust vaccine adjuvant for promoting long-term immunological memory

Although retaining antigens at the injection site (the so-called “depot effect”) is an important strategy for vaccine development, increasing evidence showed that lymphatic-targeted vaccine delivery with liposomes could be a promising approach for improving vaccine efficacy. However, it remains unclear whether antigen depot or lymphatic targeting would benefit long-term immunological memory, a major determinant of vaccine efficacy. In the present study, OVA antigen was encapsulated with DOTAP cationic liposomes (LP) or DOTAP-PEG-mannose liposomes (LP-Man) to generate depot or lymphatic-targeted liposome vaccines, respectively. The result of in vivo imaging showed that LP mostly accumulated near the injection site, whereas LP-Man not only effectively accumulated in draining lymph nodes (LNs) and the spleen, but also enhanced the uptake by resident antigen-presenting cells. Although LP vaccines with depot effect induced anti-OVA IgG more potently than LP-Man vaccines did on day 40 after priming, they failed to mount an effective B-cell memory response upon OVA re-challenge after three months. In contrast, lymphatic-targeted LP-Man vaccines elicited sustained antibody production and robust recall responses three months after priming, suggesting lymphatic targeting rather than antigen au to depot promoted the establishment of long-term memory responses. The enhanced long-term immunological memory by LP-Man was attributed to vigorous germinal center responses as well as increased Tfh cells and central memory CD4+ T cells in the secondary lymphoid organs. Hence, lymphatic-targeted vaccine delivery with LP-Man could be an effective strategy to promote long-lasting immunological memory.