A TLR9 agonist synergistically enhances protective immunity induced by an Alum-adjuvanted H7N9 inactivated whole-virion vaccine

Antigen sparing is an important strategy for pandemic vaccine development because of the limitation of worldwide vaccine production during disease outbreaks. However, several clinical studies have demonstrated that the current aluminum (Alum)-adjuvanted influenza vaccines fail to sufficiently enhance immune responses to meet licensing criteria. Here, we used pandemic H7N9 as a model virus to demonstrate that a 10-fold lower amount of vaccine antigen combined with Alum and TLR9 agonist can provide stronger protective effects than using Alum as the sole adjuvant. We found that the Alum/CpG 1018 combination adjuvant could induce more robust virus-specific humoral immune responses, including higher total IgG production, hemagglutination-inhibiting antibody activity, and neutralizing antibody titres, than the Alum-adjuvanted formulation. Moreover, this combination adjuvant shifted the immune response toward a Th1-biased immune response. Importantly, the Alum/CpG 1018-formulated vaccine could confer better protective immunity against H7N9 challenge than that adjuvanted with Alum alone. Notably, the addition of CpG 1018 to the Alum-adjuvanted H7N9 whole-virion vaccine exhibited an antigen-sparing effect without compromising vaccine efficacy. These findings have significant implications for improving Alum-adjuvanted influenza vaccines using the approved adjuvant CpG 1018 for pandemic preparedness.

Correction: DNA vaccination induced protective immunity against SARS CoV-2 infection in hamsterss

[This corrects the article DOI: 10.1371/journal.pntd.0009374.].

A DNA vaccine candidate delivered by an electroacupuncture machine provides protective immunity against SARS-CoV-2 infection

A major challenge in the use of DNA vaccines is efficient DNA delivery in vivo. Establishing a safe and efficient electric transfer method is the key to developing rapid DNA vaccines against emerging infectious diseases. To overcome the complexity of designing new electric transfer machines for DNA delivery, a clinically approved electric transfer machine could be considered as an alternative. Here, we report an electroacupuncture machine-based method for DNA vaccine delivery after intramuscular injection of the COVID-19 DNA vaccine. The S gene of SARS-CoV-2 in the pVAX1 plasmid (pSARS2-S) was used as an antigen in this study. We optimized the clinically used electroacupuncture machine settings for efficient induction of the neutralizing antibody titer after intramuscular injection of pSARS2-S in mice. We found that pSARS2-S immunization at 40 Vpp for 3-5 s could induce high neutralizing antibody titers and Th1-biased immune responses. IFN-γ/TNF-α-secreting CD4+ and CD8+ T cells were also observed in the DNA vaccination group but not in the recombinant protein vaccination group. T-cell epitope mapping shows that the major reactive epitopes were located in the N-terminal domain (a.a. 261-285) and receptor-binding domain (a.a. 352-363). Importantly, pSARS2-S immunization in hamsters could induce protective immunity against SARS-CoV-2 challenge in vivo. In the preclinical toxicology study, blood biochemistry, hematology, and DNA persistence analysis reveal that the DNA delivery method is safe. Furthermore, the raised antisera could also cross-neutralize different variants of concern. These findings suggest that DNA vaccination using an electroacupuncture machine is feasible for use in humans in the future.

DNA vaccination induced protective immunity against SARS CoV-2 infection in hamsterss

The development of efficient vaccines against COVID-19 is an emergent need for global public health. The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a major target for the COVID-19 vaccine. To quickly respond to the outbreak of the SARS-CoV-2 pandemic, a nucleic acid-based vaccine is a novel option, beyond the traditional inactivated virus vaccine or recombinant protein vaccine. Here, we report a DNA vaccine containing the spike gene for delivery via electroporation. The spike genes of SARS-CoV and SARS-CoV-2 were codon optimized for mammalian cell expression and then cloned into mammalian cell expression vectors, called pSARS-S and pSARS2-S, respectively. Spike protein expression was confirmed by immunoblotting after transient expression in HEK293T cells. After immunization, sera were collected for antigen-specific antibody and neutralizing antibody titer analyses. We found that both pSARS-S and pSARS2-S immunization induced similar levels of antibodies against S2 of SARS-CoV-2. In contrast, only pSARS2-S immunization induced antibodies against the receptor-binding domain of SARS-CoV-2. We further found that pSARS2-S immunization, but not pSARS-S immunization, could induce very high titers of neutralizing antibodies against SARS-CoV-2. We further analyzed SARS-CoV-2 S protein-specific T cell responses and found that the immune responses were biased toward Th1. Importantly, pSARS2-S immunization in hamsters could induce protective immunity against SARS-CoV-2 challenge in vivo. These data suggest that DNA vaccination could be a promising approach for protecting against COVID-19.

Development and Evaluation of Vero Cell-Derived Master Donor Viruses for Influenza Pandemic Preparedness

The embryonated egg-based platform currently produces the majority of seasonal influenza vaccines by employing a well-developed master donor virus (MDV, A/PR/8/34 (PR8)) to generate high-growth reassortants (HGRs) for A/H1N1 and A/H3N2 subtypes. Although the egg-based platform can supply enough seasonal influenza vaccines, it cannot meet surging demands during influenza pandemics. Therefore, multi-purpose platforms are desirable for pandemic preparedness. The Vero cell-based production platform is widely used for human vaccines and could be a potential multi-purpose platform for pandemic influenza vaccines. However, many wild-type and egg-derived influenza viruses cannot grow efficiently in Vero cells. Therefore, it is critical to develop Vero cell-derived high-growth MDVs for pandemic preparedness. In this study, we evaluated two in-house MDVs (Vero-15 and VB5) and two external MDVs (PR8 and PR8-HY) to generate Vero cell-derived HGRs for five avian influenza viruses (AIVs) with pandemic potentials (H5N1 clade 2.3.4, H5N1 clade 2.3.2.1, American-lineage H5N2, H7N9 first wave and H7N9 fifth wave). Overall, no single MDV could generate HGRs for all five AIVs, but this goal could be achieved by employing two in-house MDVs (vB5 and Vero-15). In immunization studies, mice received two doses of Vero cell-derived inactivated H5N1 and H7N9 whole virus antigens adjuvanted with alum and developed robust antibody responses.

Development of high-growth influenza H7N9 prepandemic candidate vaccine viruses in suspension MDCK cells

BACKGROUND

Influenza vaccine manufacturers traditionally use egg-derived candidate vaccine viruses (CVVs) to produce high-yield influenza viruses for seasonal or pandemic vaccines; however, these egg-derived CVVs need an adaptation process for the virus to grow in mammalian cells. The low yields of cell-based manufacturing systems using egg-derived CVVs remain an unsolved issue. This study aimed to develop high-growth cell-derived CVVs for MDCK cell-based vaccine manufacturing platforms.

METHODS

Four H7N9 CVVs were generated in characterized Vero and adherent MDCK (aMDCK) cells. Furthermore, reassortant viruses were amplified in adherent MDCK (aMDCK) cells with certification, and their growth characteristics were detected in aMDCK cells and new suspension MDCK (sMDCK) cells. Finally, the plaque-forming ability, biosafety, and immunogenicity of H7N9 reassortant viruses were evaluated.

RESULTS

The HA titers of these CVVs produced in proprietary suspension MDCK (sMDCK) cells and chicken embryos were 2- to 8-fold higher than those in aMDCK cells. All H7N9 CVVs showed attenuated characteristics by trypsin-dependent plaque assay and chicken embryo lethality test. The alum-adjuvanted NHRI-RG5 (derived from the fifth wave H7N9 virus A/Guangdong/SP440/2017) vaccine had the highest immunogenicity and cross-reactivity among the four H7N9 CVVs. Finally, we found that AddaVax adjuvant improved the cross-reactivity of low pathogenic H7N9 virus against highly pathogenic H7N9 viruses.

CONCLUSIONS

Our study indicates that cell-derived H7N9 CVVs possessed high growth rate in new sMDCK cells and low pathogenicity in chicken embryo, and that CVVs generated by this platform are also suitable for both cell- and egg-based prepandemic vaccine production.

Assessing the therapeutic potential of Graptopetalum paraguayense on Alzheimer's disease using patient iPSC-derived neurons

Alzheimer’s disease (AD) is the most common type of dementia and also one of the leading causes of death worldwide. However, the underlying mechanisms remain unclear, and currently there is no drug treatment that can prevent or cure AD. Here, we have applied the advantages of using induced pluripotent stem cell (iPSC)-derived neurons (iNs) from AD patients, which are able to offer human-specific drug responsiveness, in order to evaluate therapeutic candidates for AD. Using approach involving an inducible neurogenin-2 transgene, we have established a robust and reproducible protocol for differentiating human iPSCs into glutamatergic neurons. The AD-iN cultures that result have mature phenotypic and physiological properties, together with AD-like biochemical features that include extracellular β-amyloid (Aβ) accumulation and Tau protein phosphorylation. By screening using a gene set enrichment analysis (GSEA) approach, Graptopetalum paraguayense (GP) has been identified as a potential therapeutic agent for AD from among a range of Chinese herbal medicines. We found that administration of a GP extract caused a significantly reduction in the AD-associated phenotypes of the iNs, including decreased levels of extracellular Aβ40 and Aβ42, as well as reduced Tau protein phosphorylation at positions Ser214 and Ser396. Additionally, the effect of GP was more prominent in AD-iNs compared to non-diseased controls. These findings provide valuable information that suggests moving extracts of GP toward drug development, either for treating AD or as a health supplement to prevent AD. Furthermore, our human iN-based platform promises to be a useful strategy when it is used for AD drug discovery.

Process development for pandemic influenza VLP vaccine production using a baculovirus expression system

Background

Influenza viruses cause hundreds of thousands of respiratory diseases worldwide each year, and vaccination is considered the most effective approach for preventing influenza annual epidemics or pandemics. Since 1950, chicken embryonated eggs have been used as the main method for producing seasonal influenza vaccines. However, this platform has the main drawback of a lack of scale-up flexibility, and thus, egg-based vaccine manufacturers cannot supply sufficient doses within a short period for use for pandemic prevention. As a result, strategies for reducing the manufacturing time and increasing production capacity are urgently needed. Non-virion vaccine methods have been considered an alternative strategy against an influenza pandemic, and the purpose of maintaining an immunogenic capsule structure with infectious properties appears to be met by the virus-like particle (VLP) platform.

Results

An influenza H7N9-TW VLP production platform using insect cells, which included the expression of hemagglutinin (HA), NA, and M1 proteins, was established. To scale up H7N9-TW VLP production, several culture conditions were optimized to obtain a higher production yield. A high level of dissolved oxygen (DO) could be critical to H7N9-TW VLP production. If the DO was maintained at a high level, the HA titer obtained in the spinner flask system with ventilation was similar to that obtained in a shake flask. In this study, the HA titer in a 5-L bioreactor with a well-controlled DO level was substantially improved by 128-fold (from 4 HA units (HAU)/50 μL to 512 HAU/50 μL).

Conclusions

In this study, a multigene expression platform and an effective upstream process were developed. Notably, a high H7N9-TW VLP yield was achieved using a two-step production strategy while a high DO level was maintained. The upstream process, which resulted in high VLP titers, could be further used for large-scale influenza VLP vaccine production.

The stability and immunogenicity of inactivated MDCK cell-derived influenza H7N9 viruses

In recent years, cell-based influenza vaccines have gained a great interest over the egg-based vaccines. Several inactivated H7N9 vaccines have been evaluated in clinical trials, including whole-virion vaccines, split vaccines and subunit vaccines. Recently, we developed a new suspension MDCK (sMDCK) cell line for influenza viruses production. However, the properties of purified antigen from sMDCK cells remain unclear. In this study, the stability of influenza H7N9 vaccine bulk derived from sMDCK cells was investigated, and the data were compared with the vaccine antigen derived from our characterized adhesion MDCK (aMDCK) cells in serum-free medium. The influenza H7N9 bulks derived from sMDCK and aMDCK cells were stored at 2-8 °C for different periods of time, and a number of parameters selected to monitor the H7N9 vaccine antigen stability were evaluated at each interval (1, 3 and 12 months). The monitored parameters included virus morphology, hemagglutinin (HA) activity, HA concentration, antigenicity, and immunogenicity. The sMDCK-derived H7N9 bulk showed similar morphology to that of the aMDCK-derived H7N9 bulk, and there were no obvious changes after the extended storage periods. Furthermore, the HA titer, HA concentration, and antigenicity of sMDCK-derived H7N9 bulk were stable after 28 months of storage. Finally, the results of hemagglutination inhibition and neutralization tests showed that sMDCK- and aMDCK-derived H7N9 vaccines had comparable immunogenicity. These results indicated that sMDCK-derived H7N9 bulk has good stability compared to that of aMDCK-derived H7N9 bulk. Thus, the newly developed suspension MDCK cell line shows a great alternative for manufacturing cell-based influenza vaccines.

Neurohealth Properties of Hericium erinaceus Mycelia Enriched with Erinacines

Hericium erinaceus, an ideal culinary-medicinal mushroom, has become a well-established candidate in promoting positive brain and nerve health-related activities by inducing the nerve growth factor from its bioactive ingredient. Among its active compounds, only erinacine A has confirmed pharmacological actions in the central nervous system in rats. Hence, this review has summarized the available information on the neurohealth properties of H. erinaceus mycelia enriched with erinacines, which may contribute to further research on the therapeutic roles of these mycelia. The safety of this mushroom has also been discussed. Although it has been difficult to extrapolate the in vivo studies to clinical situations, preclinical studies have shown that there can be improvements in ischemic stroke, Parkinson's disease, Alzheimer's disease, and depression if H. erinaceus mycelia enriched with erinacines are included in daily meals.

Xuefu Zhuyu decoction ameliorates obesity, hepatic steatosis, neuroinflammation, amyloid deposition and cognition impairment in metabolically stressed APPswe/PS1dE9 mice

ETHNOPHARMACOLOGICAL RELEVANCE

Metabolic syndrome and vascular dysfunction was suggested to be the risk factors for Alzheimer's disease (AD). Xuefu Zhuyu decoction (XZD) is a traditional Chinese medicine used to treat metabolic syndrome and cardiac-cerebral vascular disease. The effects of XZD on ameliorating metabolic syndrome, amyloid-related pathologies and cognitive impairment in an animal model of AD with metabolic stress was investigated.

MATERIALS AND METHOD

The animal model of AD with metabolic stress was created by administrating high-fat diet and a low-dose injection of streptozotocin prior to the appearance of senile plaques in APP/PS1 transgenic mice. The diabesity-associated metabolic changes and AD-related pathological alterations were examined.

RESULTS

We found that XZD reduced body weight, insulin and leptin level, HOMA-IR, hepatic triglyceride, serum Aβ42 in the metabolic stressed AD animal. XZD also ameliorated oral glucose tolerant, Aβ deposition, astrocyte and microglia activation in the vicinity of plaques, and nesting behavior in the metabolic stressed AD animal.

CONCLUSION

The results of this study suggest that XZD is able to reduce the peripheral metabolic stress-mediated vascular hypoperfusion, neuroinflammation and AD-related pathology in APP/PS1 mice.

Erinacine S, a Rare Sesterterpene from the Mycelia of Hericium erinaceus

A new sesterterpene, erinacine S, and one cyathane diterpene xyloside, erinacine A, were isolated from the ethanol extract of the mycelia of Hericium erinaceus. Their structures were elucidated by spectroscopic and X-ray analysis. A 30-day oral course of erinacines A and S attenuated Aβ plaque burden in the brains of 5-month-old female APP/PS1 transgenic mice. Moreover, erinacines A and S significantly increased the level of insulin-degrading enzyme in cerebral cortex.

A Facile and Low-Cost Method to Enhance the Internal Quantum Yield and External Light-Extraction Efficiency for Flexible Light-Emitting Carbon-Dot Films

Solution-processed, non-toxic carbon dots (CDs) have attracted much attention due to their unique photoluminescence (PL) properties. They are promising emissive layers for flexible light-emitting devices. To this end, the CDs in pristine aqueous solutions need to be transferred to form solid-state thin films without sacrificing their original PL characteristics. Unfortunately, solid-state PL quenching induced by extra non-radiative (NR) energy transfer among CDs would significantly hinder their practical applications in optoelectronics. Here, a facile, low-cost and effective method has been utilized to fabricate high-performance CD/polymer light-emitting flexible films with submicron-structured patterns. The patterned polymers can serve as a solid matrix to disperse and passivate CDs, thus achieving high internal quantum yields of 61%. In addition, they can act as an out-coupler to mitigate the waveguide-mode losses, approximately doubling the external light-extraction efficiency. Such CD/polymer composites also exhibit good photo-stability, and thus can be used as eco-friendly, low-cost phosphors for solid-state lighting.

Lithospermic acid attenuates 1-methyl-4-phenylpyridine-induced neurotoxicity by blocking neuronal apoptotic and neuroinflammatory pathways

Background

Parkinson’s disease is the second most common neurodegenerative disorders after Alzheimer’s disease. The main cause of the disease is the massive degeneration of dopaminergic neurons in the substantia nigra. Neuronal apoptosis and neuroinflammation are thought to be the key contributors to the neuronal degeneration.

Results

Both CATH.a cells and ICR mice were treated with 1-methyl-4-phenylpyridin (MPP⁺) to induce neurotoxicity in vitro and in vivo. Western blotting and immunohistochemistry were also used to analyse neurotoxicity, neuroinflammation and aberrant neurogenesis in vivo. The experiment in CATH.a cells showed that the treatment of MPP⁺ impaired intake of cell membrane and activated caspase system, suggesting that the neurotoxic mechanisms of MPP⁺ might include both necrosis and apoptosis. Pretreatment of lithospermic acid might prevent these toxicities. Lithospermic acid possesses specific inhibitory effect on caspase 3. In mitochondria, MPP⁺ caused mitochondrial depolarization and induced endoplasmic reticulum stress via increasing expression of chaperone protein, GRP-78. All the effects mentioned above were reduced by lithospermic acid. In animal model, the immunohistochemistry of mice brain sections revealed that MPP⁺ decreased the amount of dopaminergic neurons, enhanced microglia activation, promoted astrogliosis in both substantia nigra and hippocampus, and MPP⁺ provoked the aberrant neurogenesis in hippocampus. Lithospermic acid significantly attenuates all of these effects induced by MPP⁺.

Conclusions

Lithospermic acid is a potential candidate drug for the novel therapeutic intervention on Parkinson’s disease.

Cinnamaldehyde inhibits the tumor necrosis factor-alpha-induced expression of cell adhesion molecules in endothelial cells by suppressing NF-kappaB activation: effects upon IkappaB and Nrf2

The production of adhesion molecules and subsequent attachment of leukocytes to endothelial cells (ECs) are critical early events in atherogenesis. These adhesion molecules thus play an important role in the development of this disease. Recent studies have highlighted the chemoprotective and anti-inflammatory effects of cinnamaldehyde, a Cinnamomum cassia Presl-specific diterpene. In our current study, we have examined the effects of both cinnamaldehyde and extracts of C. cassia on cytokine-induced monocyte/human endothelial cell interactions. We find that these compounds inhibit the adhesion of TNFalpha-induced monocytes to endothelial cells and suppress the expression of the cell adhesion molecules, VCAM-1 and ICAM-1, at the transcriptional level. Moreover, in TNFalpha-treated ECs, the principal downstream signal of VCAM-1 and ICAM-1, NF-kappaB, was also found to be abolished in a time-dependent manner. Interestingly, cinnamaldehyde exerts its anti-inflammatory effects by blocking the degradation of the inhibitory protein IkappaB-alpha, but only in short term pretreatments, whereas it does so via the induction of Nrf2-related genes, including heme-oxygenase-1 (HO-1), over long term pretreatments. Treating ECs with zinc protoporphyrin, a HO-1 inhibitor, partially blocks the anti-inflammatory effects of cinnamaldehyde. Elevated HO-1 protein levels were associated with the inhibition of TNFalpha-induced ICAM-1 expression. In addition to HO-1, we also found that cinnamaldehyde can upregulate Nrf2 in nuclear extracts, and can increase ARE-luciferase activity and upregulate thioredoxin reductase-1, another Nrf2-related gene. Moreover, cinnamaldehyde exposure rapidly reduces the cellular GSH levels in ECs over short term treatments but increases these levels after 9 h exposure. Hence, our present findings indicate that cinnamaldehyde suppresses TNF-induced singling pathways via two distinct mechanisms that are activated by different pretreatment periods.