RNAi-mediated suppression of endogenous storage proteins leads to a change in localization of overexpressed cholera toxin B-subunit and the allergen protein RAG2 in rice seeds

RNAi-mediated suppression of the endogenous storage proteins in MucoRice-CTB-RNAi seeds affects not only the levels of overexpressed CTB and RAG2 allergen, but also the localization of CTB and RAG2. A purification-free rice-based oral cholera vaccine (MucoRice-CTB) was previously developed by our laboratories using a cholera toxin B-subunit (CTB) overexpression system. Recently, an advanced version of MucoRice-CTB was developed (MucoRice-CTB-RNAi) through the use of RNAi to suppress the production of the endogenous storage proteins 13-kDa prolamin and glutelin, so as to increase CTB expression. The level of the α-amylase/trypsin inhibitor-like protein RAG2 (a major rice allergen) was reduced in MucoRice-CTB-RNAi seeds in comparison with wild-type (WT) rice. To investigate whether RNAi-mediated suppression of storage proteins affects the localization of overexpressed CTB and major rice allergens, we generated an RNAi line without CTB (MucoRice-RNAi) and investigated gene expression, and protein production and localization of two storage proteins, CTB, and five major allergens in MucoRice-CTB, MucoRice-CTB-RNAi, MucoRice-RNAi, and WT rice. In all lines, glyoxalase I was detected in the cytoplasm, and 52- and 63-kDa globulin-like proteins were found in the aleurone particles. In WT, RAG2 and 19-kDa globulin were localized mainly in protein bodies II (PB-II) of the endosperm cells. Knockdown of glutelin A led to a partial destruction of PB-II and was accompanied by RAG2 relocation to the plasma membrane/cell wall and cytoplasm. In MucoRice-CTB, CTB was localized in the cytoplasm and PB-II. In MucoRice-CTB-RNAi, CTB was produced at a level six times that in MucoRice-CTB and was localized, similar to RAG2, in the plasma membrane/cell wall and cytoplasm. Our findings indicate that the relocation of CTB in MucoRice-CTB-RNAi may contribute to down-regulation of RAG2.

Induction of toxin-specific neutralizing immunity by molecularly uniform rice-based oral cholera toxin B subunit vaccine without plant-associated sugar modification

Plants have been used as expression systems for a number of vaccines. However, the expression of vaccines in plants sometimes results in unexpected modification of the vaccines by N-terminal blocking and sugar-chain attachment. Although MucoRice-CTB was thought to be the first cold-chain-free and unpurified oral vaccine, the molecular heterogeneity of MucoRice-CTB, together with plant-based sugar modifications of the CTB protein, has made it difficult to assess immunological activity of vaccine and yield from rice seed. Using a T-DNA vector driven by a prolamin promoter and a signal peptide added to an overexpression vaccine cassette, we established MucoRice-CTB/Q as a new generation oral cholera vaccine for humans use. We confirmed that MucoRice-CTB/Q produces a single CTB monomer with an Asn to Gln substitution at the 4th glycosylation position. The complete amino acid sequence of MucoRice-CTB/Q was determined by MS/MS analysis and the exact amount of expressed CTB was determined by SDS-PAGE densitometric analysis to be an average of 2.35 mg of CTB/g of seed. To compare the immunogenicity of MucoRice-CTB/Q, which has no plant-based glycosylation modifications, with that of the original MucoRice-CTB/N, which is modified with a plant N-glycan, we orally immunized mice and macaques with the two preparations. Similar levels of CTB-specific systemic IgG and mucosal IgA antibodies with toxin-neutralizing activity were induced in mice and macaques orally immunized with MucoRice-CTB/Q or MucoRice-CTB/N. These results show that the molecular uniformed MucoRice-CTB/Q vaccine without plant N-glycan has potential as a safe and efficacious oral vaccine candidate for human use.

Rice-based oral antibody fragment prophylaxis and therapy against rotavirus infection

Rotavirus-induced diarrhea is a life-threatening disease in immunocompromised individuals and in children in developing countries. We have developed a system for prophylaxis and therapy against rotavirus disease using transgenic rice expressing the neutralizing variable domain of a rotavirus-specific llama heavy-chain antibody fragment (MucoRice-ARP1). MucoRice-ARP1 was produced at high levels in rice seeds using an overexpression system and RNAi technology to suppress the production of major rice endogenous storage proteins. Orally administered MucoRice-ARP1 markedly decreased the viral load in immunocompetent and immunodeficient mice. The antibody retained in vitro neutralizing activity after long-term storage (>1 yr) and boiling and conferred protection in mice even after heat treatment at 94°C for 30 minutes. High-yield, water-soluble, and purification-free MucoRice-ARP1 thus forms the basis for orally administered prophylaxis and therapy against rotavirus infections.

MucoRice-cholera toxin B-subunit, a rice-based oral cholera vaccine, down-regulates the expression of α-amylase/trypsin inhibitor-like protein family as major rice allergens

To develop a cold chain- and needle/syringe-free rice-based cholera vaccine (MucoRice-CTB) for human use, we previously advanced the MucoRice system by introducing antisense genes specific for endogenous rice storage proteins and produced a molecularly uniform, human-applicable, high-yield MucoRice-CTB devoid of plant-associated sugar. To maintain the cold chain-free property of this vaccine for clinical application, we wanted to use a polished rice powder preparation of MucoRice-CTB without further purification but wondered whether this might cause an unexpected increase in rice allergen protein expression levels in MucoRice-CTB and prompt safety concerns. Therefore, we used two-dimensional fluorescence difference gel electrophoresis and shotgun MS/MS proteomics to compare rice allergen protein expression levels in MucoRice-CTB and wild-type (WT) rice. Both proteomics analyses showed that the only notable change in the expression levels of rice allergen protein in MucoRice-CTB, compared with those in WT rice, was a decrease in the expression levels of α-amylase/trypsin inhibitor-like protein family such as the seed allergen protein RAG2. Real-time PCR analysis showed mRNA of RAG2 reduced in MucoRice-CTB seed. These results demonstrate that no known rice allergens appear to be up-reregulated by genetic modification of MucoRice-CTB, suggesting that MucoRice-CTB has potential as a safe oral cholera vaccine for clinical application.

Effect of cilostazol in preventing restenosis after carotid artery stenting using the carotid wallstent: a multicenter retrospective study

BACKGROUND AND PURPOSE

Restenosis after CAS is a postoperative problem, with a reported frequency of approximately 2%-8%. However differences in stent design, procedure, and the antiplatelet agent appear to affect the incidence of restenosis. We assessed the frequency of restenosis and the effect of the antiplatelet agent CLZ in preventing restenosis after CAS by the standard procedure using the CWS.

MATERIALS AND METHODS

Between May 2010 and October 2011, 62 lesions in 60 consecutive patients underwent CAS using the CWS at 4 medical institutions, and all patients were followed clinically and assessed by sonography, 3D-CTA, or angiography at 3 and 6 months postoperatively. Restenosis was defined as ≥50% stenosis. The incidence of restenosis and the variation in the incidence of restenosis by the difference in type of antiplatelet agent between the CLZ group (n = 30; aspirin, 100 mg, and CLZ, 200 mg) and the non-CLZ group (n = 32; aspirin, 100 mg, and clopidogrel, 75 mg [n = 29]; or ticlopidine, 100 mg [n = 2] or 200 mg [n = 1]) were retrospectively investigated. Two antiplatelet agents were given starting 1 week preoperatively until at least 3 months postoperatively.

RESULTS

Restenosis occurred in 5 patients (8.3%), but all were cases of asymptomatic lesions in the follow-up period. All 5 patients with restenosis were in the non-CLZ group, with no cases of restenosis in the CLZ group; the difference was significant (P = .0239).

CONCLUSIONS

The restenosis rate after CAS by using the CWS was 8.3%. CLZ was associated with significant inhibition of restenosis.

RNAi suppression of rice endogenous storage proteins enhances the production of rice-based Botulinum neutrotoxin type A vaccine

Mucosal vaccines based on rice (MucoRice) offer a highly practical and cost-effective strategy for vaccinating large populations against mucosal infections. However, the limitation of low expression and yield of vaccine antigens with high molecular weight remains to be overcome. Here, we introduced RNAi technology to advance the MucoRice system by co-introducing antisense sequences specific for genes encoding endogenous rice storage proteins to minimize storage protein production and allow more space for the accumulation of vaccine antigen in rice seed. When we used RNAi suppression of a combination of major rice endogenous storage proteins, 13 kDa prolamin and glutelin A in a T-DNA vector, we could highly express a vaccine comprising the 45 kDa C-terminal half of the heavy chain of botulinum type A neurotoxin (BoHc), at an average of 100 μg per seed (MucoRice-BoHc). The MucoRice-Hc was water soluble, and was expressed in the cytoplasm but not in protein body I or II of rice seeds. Thus, our adaptation of the RNAi system improved the yield of a vaccine antigen with a high molecular weight. When the mucosal immunogenicity of the purified MucoRice-BoHc was examined, the vaccine induced protective immunity against a challenge with botulinum type A neurotoxin in mice. These findings demonstrate the efficiency and utility of the advanced MucoRice system as an innovative vaccine production system for generating highly immunogenic mucosal vaccines of high-molecular-weight antigens.

Adjuvant-free nanogel-based PspA nasal vaccine for the induction of protective immunity against Pneumococcus (166.7)

To establish strategically effective and attractive vaccine against pneumococcal respiratory infections, combining the current knowledge and technology for common antigen throughout pneumococcal strains and the new delivery system is essential. Here, we introduce a new pneumococcal nasal vaccine using the advantages of Pneumococcal surface protein A (PspA) antigen and a new adjuvant-free intranasal vaccine-delivery system with a nanometer-sized hydrogel (nanogel) consisting of a cationic type of cholesteryl group-bearing pullulan (cCHP). Nanogel-based PspA nasal vaccination induced high levels of antigen-specific serum IgG, and nasal and bronchial secretory IgA (SIgA) antibodies. The levels of PspA-specific antibodies were as high as those in mice nasally immunized with PspA and mucosal adjuvant, cholera toxin. The nanogel induced PspA-specific immune responses provided protective immunity against the lethal challenge with Streptococcus pneumoniae Xen10. Nanogel-PspA vaccinated group thus had less numbers of pneumococcus on the surface of the bronchial mucosa, and perfectly protected from the pneumococcal invasion of the lung parenchyma. These results demonstrate the effectiveness of the nanogel-based PspA nasal vaccine system as an adjuvant free mucosal vaccine against the respiratory infection of pneumococcus.

In vivo molecular imaging for a nasal botulism vaccine in mice and nonhuman primates (53.8)

Nasal administration is an effective route for a needle-free vaccine. However, safety concerns were raised by the potential of nasally administered antigens to reach the central nervous system. We tested the real-time quantitative tracking of a nasal vaccine candidate for botulism, which is a recombinant nontoxic fragment of botulinus toxin A (BoHc/A), by using a newly established in vivo imaging method, [18F]-labeled BoHc/A-positron emission tomography (PET). This method provides results that are consistent with direct counting of [18F] radioactivity or the traditional [111In]-radiolabel method in dissected tissues of mice and non-human primates. In addition, no deposition of BoHc/A in the cerebrum and olfactory bulb was found after nasal administration of [18F]-BoHc/A in mice and non-human primates. We also established a real-time quantitative profile of elimination of this nasal vaccine candidate and demonstrated that it induces highly protective immunity against botulism in non-human primates. These results demonstrate a new way to use in vivo imaging for safety evaluation of nasal vaccines.

Passive oral rice-based antibody prophylaxis and therapy against rotavirus infection (106.19)

Rotavirus-induced diarrhea is a life-threatening disease in children in developing countries. We have developed a novel system for prophylaxis and therapy against rotavirus using transgenic rice expressing the neutralizing variable domain of llama heavy-chain antibody fragments against rhesus-monkey rotavirus serotype G3P (MucoRice-ARP1). MucoRice-ARP1 was produced at high levels in rice seeds using an overexpression system and RNAi technology to suppress the production of major rice endogenous storage proteins. MucoRice-ARP1 was water-soluble and expressed in protein body II as a rice storage organelle and cytoplasm between protein bodies of in rice. We confirmed the full sequence of 123 amino acids of ARP1 by mass spectrometry. MucoRice-ARP1 neutralized human RV strains (ST-3 G4P[6], 69M G8P[10], F45 G9P[8], P G3P[8] and Va70 G4P[8]) in vitro. When administered orally, MucoRice-ARP1 markedly decreased the prevalence of diarrhea and viral load in a murine pup model. Long-term storage (>1yr) at room temperature of MucoRice-ARP1 did not impair its in vivo neutralizing activity. Oral MucoRice-ARP1 thus offer a novel cost-effective approach to prevent and treat rotavirus-induced diarrhea not only in children but also in adults who would not be expected to respond to the live attenuated vaccine.

Distinct fucosylation of M cells and epithelial cells by Fut1 and Fut2, respectively, in response to intestinal environmental stress

The intestinal epithelium contains columnar epithelial cells (ECs) and M cells, and fucosylation of the apical surface of ECs and M cells is involved in distinguishing the two populations and in their response to commensal flora and environmental stress. Here, we show that fucosylated ECs (F-ECs) were induced in the mouse small intestine by the pro-inflammatory agents dextran sodium sulfate and indomethacin, in addition to an enteropathogen derived cholera toxin. Although F-ECs showed specificity for the M cell-markers, lectin Ulex europaeus agglutinin-1 and our monoclonal antibody NKM 16-2-4, these cells also retained EC-phenotypes including an affinity for the EC-marker lectin wheat germ agglutinin. Interestingly, fucosylation of Peyer's patch M cells and F-ECs was distinctly regulated by α(1,2)fucosyltransferase Fut1 and Fut2, respectively. These results indicate that Fut2-mediated F-ECs share M cell-related fucosylated molecules but maintain distinctive EC characteristics, Fut1 is, therefore, a reliable marker for M cells.

In vivo molecular imaging analysis of a nasal vaccine that induces protective immunity against botulism in nonhuman primates

Nasal administration is an effective route for a needle-free vaccine. However, nasally administered Ags have the potential to reach the CNS directly from the nasal cavity, thus raising safety concerns. In this study, we performed real-time quantitative tracking of a nasal vaccine candidate for botulism, which is a nontoxic subunit fragment of Clostridium botulinum type A neurotoxin (BoHc/A) effective in the induction of the toxin-neutralizing immune response, by using (18)F-labeled BoHc/A-positron-emission tomography, an in vivo molecular imaging method. This method provides results that are consistent with direct counting of [(18)F] radioactivity or the traditional [(111)In]-radiolabel method in dissected tissues of mice and nonhuman primates. We found no deposition of BoHc/A in the cerebrum or olfactory bulb after nasal administration of (18)F-labeled BoHc/A in both animals. We also established a real-time quantitative profile of elimination of this nasal vaccine candidate and demonstrated that it induces highly protective immunity against botulism in nonhuman primates. Our findings demonstrate the efficiency and safety of a nasal vaccine candidate against botulism in mice and nonhuman primates using in vivo molecular imaging.

Nanogel antigenic protein-delivery system for adjuvant-free intranasal vaccines

Nanotechnology is an innovative method of freely controlling nanometre-sized materials. Recent outbreaks of mucosal infectious diseases have increased the demands for development of mucosal vaccines because they induce both systemic and mucosal antigen-specific immune responses. Here we developed an intranasal vaccine-delivery system with a nanometre-sized hydrogel ('nanogel') consisting of a cationic type of cholesteryl-group-bearing pullulan (cCHP). A non-toxic subunit fragment of Clostridium botulinum type-A neurotoxin BoHc/A administered intranasally with cCHP nanogel (cCHP-BoHc/A) continuously adhered to the nasal epithelium and was effectively taken up by mucosal dendritic cells after its release from the cCHP nanogel. Vigorous botulinum-neurotoxin-A-neutralizing serum IgG and secretory IgA antibody responses were induced without co-administration of mucosal adjuvant. Importantly, intranasally administered cCHP-BoHc/A did not accumulate in the olfactory bulbs or brain. Moreover, intranasally immunized tetanus toxoid with cCHP nanogel induced strong tetanus-toxoid-specific systemic and mucosal immune responses. These results indicate that cCHP nanogel can be used as a universal protein-based antigen-delivery vehicle for adjuvant-free intranasal vaccination.

Secretory IgA responses induced by rice-based oral cholera toxin B subunit vaccine are solely responsible for antibody-mediated long-standing cross-protection against Vibrio cholerae - and enterotoxigenic Escherichia coli -induced diarrhea (46.3)

Introduction: We investigated whether the cholera toxin B subunit (CTB)-specific secretory IgA (SIgA) induced by rice-based oral vaccine expressing CTB (MucoRice-CTB) gives long-term protection against V. cholerae - and enterotoxigenic Escherichia coli (ETEC)-induced diarrhea. Methods: Mice were orally immunized with MucoRice-CTB, which stored at room temperature for 3 years, and then evaluated for induction of SIgA-mediated protective immunity against CT or heat-labile enterotoxin (LT). The role of CTB-specific SIgA was also examined in polyimmunoglobulin receptor (pIgR)-deficient mice. Long-term immune memory was evaluated 6 months after final primary immunization. In vivo V. cholerae (El Tor O1 Inaba) and ETEC challenge was performed in the intestinal loops of immunized mice. Results: Oral MucoRice-CTB immunization provided SIgA-mediated protection against LT- or CT-induced diarrhea. This protection was impaired in pIgR-deficient mice. The vaccine offered long-lasting protection against toxin-induced diarrhea (for at least 6 months after primary immunization), and a single booster immunization extended the length of protective immunity for at least 4 more months. In the intestinal loop assay, MucoRice-CTB vaccination inhibited diarrhea in the face of V. cholerae and ETEC challenge. Conclusion: MucoRice-CTB is an effective cold-chain-free oral vaccine inducing CTB-specific SIgA-mediated long-term protection against V. cholerae - or ETEC-induced diarrhea.

Nanogel antigen delivery system for adjuvant-free intranasal vaccines (46.16)

Nanotechnology is an innovative method of freely controlling nanometer-sized materials. The recent outbreak of mucosal infectious diseases have increased the demands for development of mucosal vaccines because they induce antigen-specific both mucosal and systemic immune responses. However because of lacking the effective antigen delivery system to aero-digestive mucosa, co-administration of mucosal adjuvant mediating protective but also undesired immunity is continuously needed. Here we developed a novel intranasal vaccine-delivery system with a nanometer-sized hydrogel (“nanogel”) consisting of a cationic type of cholesteryl group-bearing pullulan (cCHP). A nontoxic subunit fragment of Clostridium botulinum type-A neurotoxin BoHc/A administered intranasally with cCHP nanogel (cCHP-BoHc/A) continuously adhered to the nasal epithelium and was effectively taken up by mucosal dendritic cells (DCs) after its release from the cCHP nanogel. Vigorous botulinum neurotoxin A (BoNT/A)-neutralizing serum IgG and secretory IgA antibody responses were induced without co-administration of mucosal adjuvant. Importantly, intranasally administered cCHP-BoHc/A did not accumulate in the olfactory bulbs or brain. Moreover, intranasally immunized tetanus toxoid (TT) with cCHP nanogel induced strong TT-specific systemic and mucosal immune responses. These results indicate that cCHP nanogel can be used as a universal protein-based antigen-delivery vehicle for adjuvant-free intranasal vaccination.

A rice-based oral cholera vaccine induces macaque-specific systemic neutralizing antibodies but does not influence pre-existing intestinal immunity

We previously showed that oral immunization of mice with a rice-based vaccine expressing cholera toxin (CT) B subunit (MucoRice-CT-B) induced CT-specific immune responses with toxin-neutralizing activity in both systemic and mucosal compartments. In this study, we examined whether the vaccine can induce CT-specific Ab responses in nonhuman primates. Orally administered MucoRice-CT-B induced high levels of CT-neutralizing serum IgG Abs in the three cynomolgus macaques we immunized. Although the Ab level gradually decreased, detectable levels were maintained for at least 6 mo, and high titers were rapidly recovered after an oral booster dose of the rice-based vaccine. In contrast, no serum IgE Abs against rice storage protein were induced even after multiple immunizations. Additionally, before immunization the macaques harbored intestinal secretory IgA (SIgA) Abs that reacted with both CT and homologous heat-labile enterotoxin produced by enterotoxigenic Escherichia coli and had toxin-neutralizing activity. The SIgA Abs were present in macaques 1 mo to 29 years old, and the level was not enhanced after oral vaccination with MucoRice-CT-B or after subsequent oral administration of the native form of CT. These results show that oral MucoRice-CT-B can effectively induce CT-specific, neutralizing, serum IgG Ab responses even in the presence of pre-existing CT- and heat-labile enterotoxin-reactive intestinal SIgA Abs in nonhuman primates.

Sympathovagal effects of spinal anaesthesia with intrathecal or intravenous fentanyl assessed by heart rate variability

BACKGROUND

Although many investigators previously reported the sympathovagal effect of spinal anaesthesia, there is no information about the sympathovagal effects of supplementation with fentanyl. The aim of this study was to evaluate the sympathovagal effects of intrathecal or intravenous fentanyl added to spinal anaesthesia.

METHODS

One hundred and twenty patients undergoing elective transurethral surgery under spinal anaesthesia were randomly allocated to receive intrathecally either isobaric bupivacaine alone (Group B), bupivacaine supplemented with intrathecal (Group Ft) or with intravenous fentanyl (Group Fv). Heart rate variability was estimated using the MemCalc method (Tarawa, Suwa Trust, Japan) before and after spinal anaesthesia.

RESULTS

In all groups, spinal anaesthesia significantly decreased low frequency/high frequency (LF/HF) as a marker of sympathovagal balance. However, patients in Group B with a low block height developed a marked increase in LF/HF after spinal anaesthesia, which was attenuated in Group Ft. Meanwhile, intravenous fentanyl did not attenuate this response.

CONCLUSION

We conclude that sympathetic activation observed in patients with a low block height was attenuated by intrathecal fentanyl but not by intravenous fentanyl.

Electron transmission characteristics of Au/1,4-benzenedithiol/Au junctions

Electron transmission through individual 1,4-benzenedithiol molecules bridging between two gold electrodes (Au/BDT/Au junctions) has been studied by measuring the current-voltage (I-V) characteristics. Measurements were made at room temperature on three junction states of conductance 0.005G(0), 0.01G(0), and 0.1G(0), respectively, where G(0) is the quantum unit of conductance. All I-V curves are linear around zero bias and nonlinearly increase upward for biases above approximately 0.2 V. Absence of plateaus in the observed I-V characteristics up to +/- 1 V indicates that the electron transmission spectrum of Au/BDT/Au has no peaks within +/- 0.5 eV from the Fermi level.