STING and TLR7/8 agonists-based nanovaccines for synergistic antitumor immune activation.

Immunostimulatory therapies based on pattern recognition receptors (PRRs) have emerged as an effective approach in the fight against cancer, with the ability to recruit tumor-specific lymphocytes in a low-immunogenicity tumor environment. The agonist cyclic dinucleotides (CDNs) of the stimulator of interferon gene (STING) are a group of very promising anticancer molecules that increase tumor immunogenicity by activating innate immunity. However, the tumor immune efficacy of CDNs is limited by several factors, including relatively narrow cytokine production, inefficient delivery to STING, and rapid clearance. In addition, a single adjuvant molecule is unable to elicit a broad cytokine response and thus cannot further amplify the anticancer effect. To address this problem, two or more agonist molecules are often used together to synergistically enhance immune efficacy. In this work, we found that a combination of the STING agonist CDGSF and the Toll-like receptor 7/8 (TLR7/8) agonist 522 produced a broader cytokine response. Subsequently, we developed multicomponent nanovaccines (MCNVs) consisting of a PC7A polymer as a nanocarrier encapsulating the antigen OVA and adjuvant molecules. These MCNVs activate bone marrow-derived dendritic cells (BMDCs) to produce multiple proinflammatory factors that promote antigen cross-presentation to stimulate specific antitumor T-cell responses. In in vivo experiments, we observed that MCNVs triggered a strong T-cell response in tumor-infiltrating lymphocytes, resulting in significant tumor regression and, notably, a 100% survival rate in mice through 25 days without other partnering therapies. These data suggest that our nanovaccines have great potential to advance cancer immunotherapy with increased durability and potency. Electronic Supplementary Material: Supplementary material (synthesis of CDGSF, 522, PC7A and OVA; preparation of MCNVs; representative gating strategies for flow cytometry) is available in the online version of this article at 10.1007/s12274-022-4282-x.

The coupling effect of cellulose nanocrystal and strong shear field achieved the strength and toughness balance of Polylactide.

Up to now, unbalanced mechanical properties and poor heat resistance have become two major problems of polylactic acid (PLA). In this study, the coupling between Cellulose nanocrystal (CNC) and strong shearing field formed a unique hierarchical structure. Compared with pure PLA, the tensile strength of DPIM PLA/CNC increased from 57.9 MPa to 79.6 MPa without sacrificing the toughness of PLA, and the vicat softening temperature of DPIM PLA/CNC increased from 60 °C to 155 °C. The microstructure of PLA/CNC composites was analyzed by SEM, SAXS and WAXD, and it was found that the coupling effect of CNC and strong shear flow field could significantly change the crystallization behavior of PLA. CNC could increase PLA shish length from 251 nm to 889 nm under the action of shear field. At the same time, due to this coupling effect, more PLA shish-kebab structures were induced at the interface. This special hierarchical structure composed of CNC and PLA Shish-Kebab is of great significance and can provide important guidance for achieving the balance of strength and toughness of polymer materials.

A chitosan-mediated inhalable nanovaccine against SARS-CoV-2.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with several antigenic variants, has grown into a global challenge, and the rapid establishment of an immune barrier is crucial to achieving long-term control of the virus. This has led to a great demand for easy preparation and scalable vaccines, especially in low-income countries. Here, we present an inhalable nanovaccine comprising chitosan and SARS-CoV-2 spike protein. The chitosan-mediated nanovaccine enabled a strong spike-specific antibody immune response and augmented local mucosal immunity in bronchoalveolar lavage and lungs, which might be capable of protecting the host from infection without systemic toxicity. In addition, the enhanced adaptive immunity stimulated by chitosan showed potential protection against SARS-CoV-2. Furthermore, inhalation of the nanovaccine induced a comparable antibody response compared to intramuscular injection. This inhalable nanovaccine against SARS-CoV-2 offers a convenient and compliant strategy to reduce the use of needles and the need for medical staff. Electronic Supplementary Material: Supplementary material (the immune activation of CS-mediated nanovacccine on BMDCs, cell viability, immune responses in lungs and BALF, serum chemistry and H&E histopathological analysis.) is available in the online version of this article at 10.1007/s12274-021-4012-9.

Overcoming STING Agonists Barriers: Peptide, Protein, and Biomembrane-based Biocompatible Delivery Strategies.

After development for more than ten years, stimulator of interferon genes (STING), a representative of pattern recognition receptors (PRRs), is now entering the stage of widespread applications. Along with the evolution of STING agonists of cyclic dinucleotides (CDNs) and non-nucleotide molecules, the stability of agonists has been improved. However, their poor performance in clinical trials triggers urgent demands for highly effective delivery strategies to further improve the cellular permeability, tissue targetability and retention. In this review, we summarized the recent progress of STING agonists applications and delivery strategies with a focus on the biocompatible platforms of peptide, protein and biomembrane, providing a novel vision for the STING field and future direction.

Regulation of liquid-liquid phase separation with focus on post-translational modifications.

Liquid-liquid phase separation (LLPS), a type of phase transition that is important in organisms, is a unique means of forming biomolecular condensates. LLPS plays a significant role in transcription, genome organisation, immune response and cell signaling, and its dysregulation may cause neurodegenerative diseases and cancers. Exploring the regulatory mechanism of LLPS contributes to the understanding of the pathogenic mechanism of abnormal phase transition and enables potential therapeutic targets to be proposed. Many factors have been found to regulate LLPS, of which post-translational modification (PTM) is among the most important. PTMs can change the structure, charge, hydrophobicity and other properties of the proteins involved in phase separation and thereby affect the phase transition behaviour. In this review, we discuss LLPS and the regulatory effects of PTMs, RNA and molecular chaperones in a phase separation system. We introduce several common PTMs (including phosphorylation, arginine methylation, arginine citrullination, acetylation, ubiquitination and poly(ADP-ribosyl)ation), highlight recent advances regarding their roles in LLPS and describe the regulatory mechanisms behind these features. This review provides a detailed overview of the field that will help further the understanding of and interventions in LLPS.

Black phosphorous nanosheet: A novel immune-potentiating nanoadjuvant for near-infrared-improved immunotherapy.

Intrinsic immune behaviors of nanomaterials and immune systems promote research on their adjuvanticity and the design of next generation nanovaccine-based immunotherapies. Herein, we report a promising multifunctional nanoadjuvant by exploring the immune-potentiating effects of black phosphorus nanosheets (BPs) in vitro and in vivo. The facile coating of BPs with phenylalanine-lysine-phenylalanine (FKF) tripeptide-modified antigen epitopes (FKF-OVAp@BP) enables the generation of a minimalized nanovaccine by integrating high loading capacity, efficient drug delivery, comprehensive dendritic cell (DC) activation, and biocompatibility for cancer immunotherapy. Systemic immunization elicits potent antitumor cellular immunity and significantly augments checkpoint blockade (CPB) against melanoma in a mouse model. Furthermore, near-infrared (NIR) photothermal effects of BPs create an immune-favorable microenvironment for improved local immunization. This study offers new insight into the integration of immunoactivity and photothermal effects for enhanced cancer immunotherapy by using a nanoadjuvant and thus potentially advances the design and application of multifunctional adjuvant materials for cancer nanotreatment.

A novel STING agonist for cancer immunotherapy and a SARS-CoV-2 vaccine adjuvant.

A novel STING agonist, CDGSF, ipsilaterally modified with phosphorothioate and fluorine, was synthesized. The phosphorothioate in CDGSF might be a site for covalent conjugation. Injection of CDGSF generated an immunogenic ("hot") tumor microenvironment to suppress melanoma, more efficiently than dithio CDG. In particular, immunization with SARS-CoV-2 spike protein using CDGSF as an adjuvant elicited an exceptionally high antibody titer and a robust T cell response, overcoming the drawbacks of aluminum hydroxide. These results highlighted the therapeutic potential of CDGSF for cancer immunotherapy and the adjuvant potential of the STING agonist in the SARS-CoV-2 vaccine for the first time.

Pam3CSK4-CDGSF Augments Antitumor Immunotherapy by Synergistically Activating TLR1/2 and STING.

Cyclic dinucleotides (CDNs), agonists of stimulator of interferon genes (STING), are promising agents for immunotherapy. However, the application of CDNs has been limited by their instability and low transmembrane efficiency. Here, we introduced a conjugated adjuvant of STING and TLR1/2, Pam3CSK4-CDGSF. Conjugating CDGSF with Pam3CSK4 increased the stability and intracellular delivery. In addition, by synergistically activating the STING and TLR pathways, Pam3CSK4-CDGSF was able to enhance immune activation. Both humoral and cellular immune responses were triggered by Pam3CSK4-CDGSF plus OVA (V4), and tumor growth was significantly inhibited after V4 administration. More importantly, V4 can also boost the antigen-specific CD8+ T cell response for cancer cell killing. Thus, the conjugated STING and TLR1/2 agonist Pam3CSK4-CDGSF can serve as a potent adjuvant for vaccine construction to augment antitumor immunotherapy.

Fully Synthetic Invariant NKT Cell-Dependent Self-Adjuvanting Antitumor Vaccines Eliciting Potent Immune Response in Mice.

Constructing an effective therapeutic cancer vaccine is very attractive and promising for cancer immunotherapy. However, the poor immunogenicity of tumor antigens and suppression of the immune system in the tumor microenvironment are two major obstacles for developing effective cancer vaccines. Invariant NKT cells (iNKT cells), which are essential bridges between the innate and adaptive immune systems, can be rapidly activated by their agonists and, consequently, evoke whole immune systems. Herein, we conjugated a potent agonist of the iNKT cell, α-galactosylceramide (α-GalCer), with the tumor-associated MUC1 glycopeptide antigens as novel self-adjuvanting cancer vaccines through click chemistry. Immunological studies revealed that the mouse immune system was potently evoked and that high levels of tumor-specific IgG antibodies were elicited by vaccine conjugates without an external adjuvant. The produced antibodies could specifically recognize and bind to antigen-expressing cancer cells and, subsequently, induce cytotoxicity through complement-dependent cytotoxicity. Thus, the insertion of α-GalCer significantly improved the immunogenicity of the MUC1 glycopeptide and induced strong antigen-specific antitumor responses, indicating that α-GalCer is an effective built-in adjuvant for constructing potent chemical synthetic antitumor vaccines.

Agonists and inhibitors of the STING pathway: Potential agents for immunotherapy.

Since being discovered in 2008, the STING (stimulator of interferon genes) pathway has gradually been recognized as a central and promising target for immunotherapy. The STING pathway can be stimulated by cyclic dinucleotides (CDNs), leading to the type I interferons (IFN) production for immunotherapy for cancer or other diseases. However, the negative charges, hydrophilicity, and instability of CDNs have hindered their further applications. In addition, chronic activation of the STING pathway has been found to be involved in autoimmune diseases as IFN overproduction. Thus, research and development of STING agonists and inhibitors has been a hot field for the treatment of several diseases. The past several years, especially 2018, has seen increasingly rapid advances in this field. Here, this review summarizes the synthesis and modification of CDNs, the identification of nonnucleotide agonists, the recent progress in delivery systems and the medical applications, such as personalized vaccine adjuvants, in detail. In addition, in this review, we summarize the STING inhibitors' advances from two aspects, covalent, and noncovalent inhibitors.

Regulation of Immune Activation by Optical Control of TLR1/2 Heterodimerization.

The activation of toll-like receptors (TLRs) plays important roles in the immune response. The ability to control the activities of TLRs could be usable as a switch for immune response. Here we have rationally designed and synthesized a photoswitchable Pam3 CSK4 derivative-P10-to control the activation of TLR1/2. The ground-state trans-P10 was able to stimulate and activate antigen-presenting cells (APCs) by promoting TLR1/2 heterodimerization. However, cis-P10, derived from UV irradiation of trans-P10, reduced the activities of APCs by impeding the TLR1/2 heterodimerization. In the absence of UV radiation, the cis-P10 slowly returned to its ground trans state, restoring the activities of the APCs stimulation. Our results indicated that optical control of TLR1/2 heterodimerization mediated by the photoswitchable P10 offers the potential to regulate immune activation and inflammation.

Data for the synthesis of new 4-aryloxy-N-arylanilines as potent succinate-cytochrome c reductase inhibitors.

In this data article, we have designed a simple and facile protocol for copper-mediated synthesis of new 4-aryloxy-N-arylanilines under mild reaction conditions. The general information and synthetic procedures of all the target compounds were provided, and they were fully characterized by Nuclear Magnetic Resonance (NMR, including 1H NMR and 13C NMR), melting point measurements, and High-Resolution Mass Spectroscopy (HRMS). Furthermore, the inhibitory activities of these compounds against succinate-cytochrome c reductase (SCR) were evaluated, and the methods and procedures of enzyme inhibition experiments were also recorded in this data article. This article is related to "Synthesis of new 4-aryloxy-N-arylanilines and their inhibitory activities against succinate-cytochrome c reductase" (Cheng et al., 2018) [1].

Targeting STING with cyclic di-GMP greatly augmented immune responses of glycopeptide cancer vaccines.

Cyclic di-GMP (CDG) was applied to MUC1 glycopeptide-based cancer vaccines with physical mixing and built-in (at 2'-OH of CDG) strategies for activating the STING pathway. CDG in both strategies behaved as a potent immunostimulant and contributed to high titers of IgG antibodies and the expression of multiple cytokines.

Synthesis of new 4-aryloxy-N-arylanilines and their inhibitory activities against succinate-cytochrome c reductase.

Succinate-cytochrome c reductase (SCR) is composed of a mixture of mitochondrial complex II (succinate-ubiquinone oxidoreductase) and complex III (cytochrome bc1 complex). Meanwhile, complexes II and III are two promising targets of numerous antibiotics and fungicides. With an aim to identify new lead structures for SCR, complex II or III, a new series of 4-aryloxy-N-arylanilines were synthesized by introducing a 4-aryloxy phenyl group as one of the aryl groups in diaryl amines. With the economic Cu(OAc)2·H2O as the optimal copper promoter, a simple and facile protocol was utilized to afford 24 target products in 56-93% yields. Furthermore, extensive screening results suggested variable inhibitory activities of these compounds against SCR. Exceptionally, compounds 7k-7n showed excellent inhibition potency with their IC50 values in the nanomolar range, demonstrating higher potency than the commercial controls (penthiopyrad and azoxystrobin) by over one order of magnitude.

Self-Assembled Nano-Immunostimulant for Synergistic Immune Activation.

Immunotherapy has become one of the most promising therapies for the treatment of diseases. Synthetic immunostimulants and nanomaterial immunostimulant systems are indispensable for the activation of the immune system in cancer immunotherapy. Herein, a strategy for preparing self-assembled nano-immunostimulants (SANIs) for synergistic immune activation is reported. Three immunostimulants self-assemble into nanoparticles through electrostatic interactions. SANIs showed strong synergistic immunostimulation in macrophages. SANIs could also induce a strong antitumor immune response to inhibit tumor growth in mice and act as an efficient adjuvant of antitumor vaccines. Therefore, SANIs may be generally applied in cancer immunotherapy. This novel SANI strategy provides a new way for the development of both immunostimulants and -suppressants.

Estimation for sparse vegetation information in desertification region based on Tiangong-1 hyperspectral image.

In order to estimate the sparse vegetation information accurately in desertification region, taking southeast of Sunite Right Banner, Inner Mongolia, as the test site and Tiangong-1 hyperspectral image as the main data, sparse vegetation coverage and biomass were retrieved based on normalized difference vegetation index (NDVI) and soil adjusted vegetation index (SAVI), combined with the field investigation data. Then the advantages and disadvantages between them were compared. Firstly, the correlation between vegetation indexes and vegetation coverage under different bands combination was analyzed, as well as the biomass. Secondly, the best bands combination was determined when the maximum correlation coefficient turned up between vegetation indexes (VI) and vegetation parameters. It showed that the maximum correlation coefficient between vegetation parameters and NDVI could reach as high as 0.7, while that of SAVI could nearly reach 0.8. The center wavelength of red band in the best bands combination for NDVI was 630nm, and that of the near infrared (NIR) band was 910 nm. Whereas, when the center wavelength was 620 and 920 nm respectively, they were the best combination for SAVI. Finally, the linear regression models were established to retrieve vegetation coverage and biomass based on Tiangong-1 VIs. R2 of all models was more than 0.5, while that of the model based on SAVI was higher than that based on NDVI, especially, the R2 of vegetation coverage retrieve model based on SAVI was as high as 0.59. By intersection validation, the standard errors RMSE based on SAVI models were lower than that of the model based on NDVI. The results showed that the abundant spectral information of Tiangong-1 hyperspectral image can reflect the actual vegetaion condition effectively, and SAVI can estimate the sparse vegetation information more accurately than NDVI in desertification region.

[Comparison of soil respiration in natural Castanopsis carlesii forest and plantation forest].

By using the Li-8100 open soil carbon flux system, the dynamic change of soil respiration rate in natural Castanopsis carlesii and plantation of Castanopsis carlesii forests in Geshikao Nature Reserve in Fujian Province of China were measured from January 2011 to December 2011, with the relationship between the dynamic changes and the relation affecting factors analyzed. The monthly variation of soil respiration in the two types of forests were both single-peaked,with the peaks appeared in early June [7.03 micromol x (m2 x s) (-1)] andlate July [5.12 micromol x (m2 x s)(-1)], respectively. The average annual soil respiration rates of the two forests were 3.74 micromol x (m2 x s)(-1) and 3.05 micromol x (m2 x s)(-1), respectively, showing significant difference. Soil temperature was the main factor affecting soil respiration, explaining 80.1% and 81.0% of the monthly variation of soil respiration. There was a significant positive correlation between the soil respiration rate and soil moisture content in natural Castanopsis carlesii forest, but lower correlation in plantation of Castanopsis carlesii forest. The soil respiration had extremely significant correlation with the litterfall mass of the current month and the month before. The Q10 values of soil respiration in natural Castanopsis carlesii and plantation of Castanopsis carlesii forests were 1.86 and 2.01, and the annual CO2 fluxes were 14.34 t x (hm2 x a)(-1) and 11.18 t x (hm2 x a)(-1), respectively. The soil respiration declined by 22.03% after natural forest was changed to plantation forest.

An enzyme-linked immunosorbent assay to measure insulin receptor dephosphorylation by PTP1B.

Considerable effort exists within drug discovery to develop novel compounds to improve the underlying metabolic defects in type 2 diabetes. One approach is focused on inhibition of the tyrosine phosphatase, PTP1B, an important negative regulator of both insulin and leptin signaling. Historically, tyrosine phosphatase assays have used either small organic phosphates or, alternatively, phosphorylated peptides from the target proteins themselves. In characterizing inhibitors of PTP1B, measuring turnover of small organic phosphates is limited to evaluation of compounds that bind the active site itself. Peptide substrates allow identification of additional subsets of inhibitors (e.g., those that bind the second aryl-phosphate site), but assays of peptide turnover often involve detection steps that then limit full kinetic evaluation of inhibitors. Here we use a polyclonal antibody specific for the phosphorylated insulin receptor to allow much more sensitive detection of peptide phosphorylation. This kinetically robust enzyme-linked immunosorbent assay (ELISA) gives k(cat) and K(m) values for a phosphorylated insulin receptor peptide consistent with values determined by a continuous fluorescence-based assay. Furthermore, IC50 values determined for well-behaved active site inhibitors agree well with values determined for p-nitrophenyl phosphate cleavage. This assay permits full characterization of a larger subset of inhibitors as drug candidates for this promising target.