Correction: Virus-Like Nanoparticle Vaccine Confers Protection against Toxoplasma gondii

[This corrects the article DOI: 10.1371/journal.pone.0161231.].

Overexpression of miR-101-2 in donor cells improves the early development of Holstein cow somatic cell nuclear transfer embryos

Accumulating studies have suggested that microRNA play a part in regulating multiple cellular processes, such as cell proliferation, apoptosis, the cell cycle, and embryo development. This study explored the effects of miR-101-2 on donor cell physiological status and the development of Holstein cow somatic cell nuclear transfer (SCNT) embryos in vitro. Holstein cow bovine fetal fibroblasts (BFF) overexpressing miR-101-2 were used as donor cells to perform SCNT; then, cleavage rate, blastocyst rate, inner cell mass-to-trophectoderm ratio, and the expression of some development- and apoptosis-related genes in different groups were analyzed. The miR-101-2 suppressed the expression of inhibitor of growth protein 3 (ING3) at mRNA and protein levels, expedited cell proliferation, and decreased apoptosis in BFF, suggesting that ING3, a target gene of miR-101-2, is a potential player in this process. Moreover, by utilizing donor cells overexpressing miR-101-2, the development of bovine SCNT embryos in vitro was significantly enhanced; the apoptotic rate in SCNT blastocysts was reduced, and the inner cell mass-to-trophectoderm ratio and SOX2, POU5F1, and BCL2L1 expression significantly increased, whereas BAX and ING3 expression decreased. Collectively, these findings suggest that miR-101-2 promotes BFF proliferation and vitality, reduces their apoptosis, and improves the early development of SCNT embryos.

Suppressive Effects of Bee Venom Acupuncture on Paclitaxel-Induced Neuropathic Pain in Rats: Mediation by Spinal α₂-Adrenergic Receptor

Paclitaxel, a chemotherapy drug for solid tumors, induces peripheral painful neuropathy. Bee venom acupuncture (BVA) has been reported to have potent analgesic effects, which are known to be mediated by activation of spinal α-adrenergic receptor. Here, we investigated the effect of BVA on mechanical hyperalgesia and spinal neuronal hyperexcitation induced by paclitaxel. The role of spinal α-adrenergic receptor subtypes in the analgesic effect of BVA was also observed. Administration of paclitaxel (total 8 mg/kg, intraperitoneal) on four alternate days (days 0, 2, 4, and 6) induced significant mechanical hyperalgesic signs, measured using a von Frey filament. BVA (1 mg/kg, ST36) relieved this mechanical hyperalgesia for at least two hours, and suppressed the hyperexcitation in spinal wide dynamic range neurons evoked by press or pinch stimulation. Both melittin (0.5 mg/kg, ST36) and phospholipase A2 (0.12 mg/kg, ST36) were shown to play an important part in this analgesic effect of the BVA, as they significantly attenuated the pain. Intrathecal pretreatment with the α₂-adrenergic receptor antagonist (idazoxan, 50 µg), but not α₁-adrenergic receptor antagonist (prazosin, 30 µg), blocked the analgesic effect of BVA. These results suggest that BVA has potent suppressive effects against paclitaxel-induced neuropathic pain, which were mediated by spinal α₂-adrenergic receptor.

The efficacy of combination treatment of gabapentin and electro-acupuncture on paclitaxel-induced neuropathic pain

Paclitaxel, a chemotherapeutic drug, induces severe peripheral neuropathy. Gabapentin (GBT) is a first line agent used to treat neuropathic pain, and its effect is mediated by spinal noradrenergic and muscarinic cholinergic receptors. Electro-acupuncture (EA) is used for treating various types of pain via its action through spinal opioidergic and noradrenergic receptors. Here, we investigated whether combined treatment of these two agents could exert a synergistic effect on paclitaxel-induced cold and mechanical allodynia, which were assessed by the acetone drop test and von Frey filament assay, respectively. Significant signs of allodynia were observed after four paclitaxel injections (a cumulative dose of 8 mg/kg, i.p.). GBT (3, 30, and 100 mg/kg, i.p.) or EA (ST36, Zusanli) alone produced dose-dependent anti-allodynic effects. The medium and highest doses of GBT (30 and 100 mg/kg) provided a strong analgesic effect, but they induced motor dysfunction in Rota-rod tests. On the contrary, the lowest dose of GBT (3 mg/kg) did not induce motor weakness, but it provided a brief analgesic effect. The combination of the lowest dose of GBT and EA resulted in a greater and longer effect, without inducing motor dysfunction. This effect on mechanical allodynia was blocked by spinal opioidergic (naloxone, 20 μg), or noradrenergic (idazoxan, 10 μg) receptor antagonist, whereas on cold allodynia, only opioidergic receptor antagonist blocked the effect. In conclusion, the combination of the lowest dose of GBT and EA has a robust and enduring analgesic action against paclitaxel-induced neuropathic pain, and it should be considered as an alternative treatment method.

Virus-Like Nanoparticle Vaccine Confers Protection against Toxoplasma gondii

The inner membrane complex (IMC) of Toxoplasma gondii as a peripheral membrane system has unique and critical roles in parasite replication, motility and invasion. Disruption of IMC sub-compartment protein produces a severe defect in T. gondii endodyogeny, the form of internal cell budding. In this study, we generated T. gondii virus-like particle particles (VLPs) containing proteins derived from IMC, and investigated their efficacy as a vaccine in mice. VLP vaccination induced Toxoplasma gondii-specific total IgG, IgG1 and IgG2a antibody responses in the sera and IgA antibody responses in the feces. Upon challenge infection with a lethal dose of T. gondii (ME49), all vaccinated mice survived, whereas all naïve control mice died. Vaccinated mice showed significantly reduced cyst load and cyst size in the brain. VLP vaccination also induced IgA and IgG antibody responses in feces and intestines, and antibody-secreting plasma cells, mixed Th1/Th2 cytokines and CD4+/CD8+ T cells from spleen. Taken together, these results indicate that non-replicating VLPs containing inner membrane complex of T. gondii represent a promising strategy for the development of a safe and effective vaccine to control the spread of Toxoplasma gondii infection.

Involvement of spinal muscarinic and serotonergic receptors in the anti-allodynic effect of electroacupuncture in rats with oxaliplatin-induced neuropathic pain

This study was performed to investigate whether the spinal cholinergic and serotonergic analgesic systems mediate the relieving effect of electroacupuncture (EA) on oxaliplatin-induced neuropathic cold allodynia in rats. The cold allodynia induced by an oxaliplatin injection (6 mg/kg, i.p.) was evaluated by immersing the rat's tail into cold water (4℃) and measuring the withdrawal latency. EA stimulation (2 Hz, 0.3-ms pulse duration, 0.2~0.3 mA) at the acupoint ST36, GV3, or LI11 all showed a significant anti-allodynic effect, which was stronger at ST36. The analgesic effect of EA at ST36 was blocked by intraperitoneal injection of muscarinic acetylcholine receptor antagonist (atropine, 1 mg/kg), but not by nicotinic (mecamylamine, 2 mg/kg) receptor antagonist. Furthermore, intrathecal administration of M₂ (methoctramine, 10 µg) and M₃ (4-DAMP, 10 µg) receptor antagonist, but not M₁ (pirenzepine, 10 µg) receptor antagonist, blocked the effect. Also, spinal administration of 5-HT₃ (MDL-72222, 12 µg) receptor antagonist, but not 5-HT_1A (NAN-190, 15 µg) or 5-HT_2A (ketanserin, 30 µg) receptor antagonist, prevented the anti-allodynic effect of EA. These results suggest that EA may have a signifi cant analgesic action against oxaliplatin-induced neuropathic pain, which is mediated by spinal cholinergic (M₂, M₃) and serotonergic (5-HT₃) receptors.

Expression levels of the hypothalamic AMPK gene determines the responsiveness of the rats to electroacupuncture-induced analgesia

BACKGROUND

Although electroacupuncture (EA) relieves various types of pain, individual differences in the sensitivity to EA analgesia have been reported, causing experimental and clinical difficulties. Our functional genomic study using cDNA microarray identified that 5'-AMP-activated protein kinase (AMPK), a well-known factor in the regulation of energy homeostasis, is the most highly expressed gene in the hypothalamus of the rats that were sensitive to EA analgesia ("responder"), as compared to the rats that were insensitive to EA analgesia ("non-responder"). In this study, we investigated the causal relationship between the hypothalamic AMPK and the individual variation in EA analgesia.

METHODS

Sprague-Dawley (SD) rats were divided into the responder and the non-responder groups, based on EA-induced analgesic effects in the tail flick latency (TFL) test, which measures the latency of the tail flick response elicited by radiant heat applied to the tail. Real-time reverse transcription-polymerase chain reaction (RT-PCR) was performed to quantify the expression levels of AMPK mRNA in the hypothalamus of the responder and non-responder rats. Further, we examined whether viral manipulation of the AMPK expression in the hypothalamus modulates EA analgesia in rats.

RESULTS

The real-time RT-PCR analysis showed that mRNA expression levels of AMPK in the hypothalamus of the responder rats are significantly higher than those of the non-responder rats, validating the previous microarray results. Microinjection of dominant negative (DN) AMPK adenovirus, which inhibits AMPK activity, into the rat hypothalamus significantly attenuates EA analgesia (p < 0.05), whereas wild type (WT) AMPK virus did not affect EA analgesia (p > 0.05).

CONCLUSIONS

The present results demonstrated that levels of AMPK gene expression in the rat hypothalamus determine the individual differences in the sensitivity to EA analgesia. Thus, our findings provide a clinically useful evidence for the application of acupuncture or EA for analgesia.

Effects of interval between fusion and activation, cytochalasin B treatment, and number of transferred embryos, on cloning efficiency in goats

To improve the efficiency of somatic cell nuclear transfer (SCNT) in goats, we evaluated the effects of the interval between fusion and activation (1 to 5 h), cytochalasin B (CB) treatment after electrofusion, and the number of transferred embryos on the in vivo and in vitro development of cloned caprine embryos. The majority of the reconstructed embryos had condensed chromosomes and metaphase-like chromosomes at 2 and 3 h after fusion; cleavage and blastocyst rates from those two groups were higher (P < 0.05) than those of embryos activated 1, 4, or 5 h after fusion. Treatment with CB between fusion and activation improved in vitro and in vivo development of nuclear transfer (NT) goat embryos by reducing the fragmentation rate (P < 0.05). Although there were no significant differences in NT efficiency, pregnancy rate and kids born per recipient were increased by transfer of 20 or 30 embryos per recipient compared with 10 embryos. We concluded that CB treatment for 2 to 3 h between fusion and activation was an efficient method for generating cloned goats by somatic cell NT. In addition, increasing the number of embryos transferred to each recipient resulted in more live offspring from fewer recipients.

Production of cloned calves by combination treatment of both donor cells and early cloned embryos with 5-aza-2/-deoxycytidine and trichostatin A

We previously reported that treatment of both donor cells and early cloned embryos with a combination of 0.01 μM 5-aza-2(/)-Deoxycytidine (5-aza-dC) and 0.05 μM trichostatin A (TSA) significantly improved development of cloned bovine embryos in vitro. In the present study, we investigated the effect of this combination treatment on the in vivo development potency and postnatal survivability of cloned calves. Blastocysts (77 and 82 blastocysts derived from untreated (control) and treated groups, respectively) were individually transferred to recipient cows. Relative to the control group, the combination treatment of both donor cells and early embryos with 5-aza-dC and TSA dramatically increased the cleavage rate (49.2 vs 63.6%, P < 0.05) at 24 h of culture, and blastocyst development rate on Days 6 and 7 of culture (18.8 vs 33.9% and 27.1 vs 38.5% respectively, P < 0.05). Although pregnancy rate did not differ 40 d after transfer, it was lower in the treated than control group 90 d after transfer (7.8 vs 29.3%, P < 0.05). In the control group, there were three calves born to 77 recipients (only two survived beyond 60 d), whereas in the treated group, 17 calves were born to 82 recipients, and 11 survived beyond 60 d. In conclusion, a combination treatment of donor cells and early cloned embryos with 5-aza-dC and TSA significantly enhanced development of somatic cell cloned bovine embryos in vivo; cloning efficiency (number of surviving calves at 60 d of birth/number of recipient cows) was increased from 2.6 to 13.4%.

A bivalent influenza VLP vaccine confers complete inhibition of virus replication in lungs

The conventional egg-grown influenza vaccines are trivalent. To test the feasibility of using multivalent influenza virus-like particles (VLPs) as an alternative influenza vaccine, we developed cell-derived influenza VLPs containing the hemagglutinin (HA) of the H1 subtype virus A/PR/8/34 or the H3 subtype virus A/Aichi/2/68 (X31). Mice immunized intramuscularly with bivalent influenza VLPs containing H1 and H3 HAs induced neutralizing activities against the homologous and closely related H1N1 strains A/PR/8/34 and A/WSN/33 as well as the H3N2 strains A/Aichi/2/68 (X31) and A/Hong Kong/68, but not the A/Philippines/2/82 strain isolated 14 years later. HA sequence and structure analysis indicated that antigenic distance could be a major factor in predicting cross-protection by VLP vaccines. The bivalent influenza VLP vaccine demonstrated advantages in broadening the protective immunity after lethal challenge infections when compared to a monovalent influenza VLP vaccine. High levels of the inflammatory cytokine IL-6 were observed in naïve or unprotected immunized mice but not in protected mice upon lethal challenge. These results indicate that multivalent influenza VLP vaccines can be an effective antigen for developing safe and alternative vaccine to control the spread of influenza viruses.

Ginseng and Salviae herbs play a role as immune activators and modulate immune responses during influenza virus infection

We have investigated the adjuvant roles of common herbal medicines (ginseng, Salviae) and their effects on early immune responses during influenza virus infection in a mouse model. Intranasal co-administration with inactivated influenza virus A (PR8) and ginseng or Salviae extract increased the levels of influenza virus specific antibodies and neutralizing activities compared to immunization with PR8 alone, and provided protective immunity. Salviae co-administration significantly enhanced IFN-gamma and IL-2 cytokine producing splenocytes while ginseng induced high levels of IL-4 and IL-5 cytokine producing cells after challenge infection. Cells expressing an early activation marker CD69 and levels of a pro-inflammatory cytokine IL-6 were highly elevated in lungs from naïve mice during challenge virus infection, which might be a mechanism in lung inflammation leading to death. In contrast, immunized mice that were co-administered ginseng or Salviae modulated CD69 expressing immune cells, did not produce IL-6, and showed significant enhancement of influenza virus specific IgA antibody in lungs after challenge virus infection. Therefore, these results indicate that both ginseng and Salviae play a role as mucosal adjuvants against influenza virus as well as immuno-modulators during influenza virus infection.

Resistance to reinfection in rats induced by irradiated metacercariae of Clonorchis sinensis

A study was made to observe the association between the resistance to reinfection induced by irradiated metacercariae (MC) of Clonorchis sinensis and antigen specific Th1- and Th2-type cytokine productions in rats. Rats were infected with 20 MC of C. sinensis, previously exposed to a single dose of gamma irradiation, which varied from 0 to 100 Gy. All of them, single dose of 12 Gy showed higher IgG antibody titer with lowest worm recovery. Thus, 50 MC were used to challenge infection in rats previously infected with 20 MC irradiated at 12 Gy and the highest resistance to challenge infection was observed. The results of lymphocyte proliferation with specific antigen, ES Ag were shown no difference of proliferative responses as compared with primary and challenge infection at 12 Gy irradiation dose. In the case of cytokines production were observed that interferon (IFN-gamma) and interlukin (IL-2) were significantly enhanced, while IL-4 and IL-10 was almost unchanged to make comparison between primary and secondary infection at 12 Gy irradiation dose. In conclusion, the single dose of 12 Gy could be adopted for induction of the highest resistance to challenge infection. Up-regulation of Th1 type cytokines, IFN-gamma and IL-2 may be affected to develop vaccine by irradiated MC.

Modified HIV envelope proteins with enhanced binding to neutralizing monoclonal antibodies

The target for neutralizing antibodies against human immunodeficiency virus (HIV) is the trimeric Env protein on the native virion. Conserved neutralizing epitopes of receptor binding sites are located in the recessed core of the Env protein, partially masked by glycosylations and variable loops. In this study, we have investigated the effects of modifications of the HIV Env protein by glycosylation site mutations, deletions of variable loops, or combinations of both types of mutations on their protein functions and reactivities with neutralizing antibodies. Modified Env proteins were expressed in insect or mammalian cells, and their reactivity with epitope-specific broadly neutralizing monoclonal antibodies (Mabs) was determined by flow cytometry. A unique mutant designated 3G with mutations in three glycosylation motifs within the V3/C3 domains surrounding the CD4 binding site showed higher levels of binding to most broadly neutralizing Mabs (b12 and 2F5) in both insect and mammalian expression systems. Mutants with a deletion of both V1 and V2 loop domains or with a unique combination of both types of mutations also bound to most neutralizing Mabs at higher levels compared to the wild-type control. Most mutants maintained the ability to bind CD4 and to induce syncytium formation at similar or higher levels as compared to that of the wild-type Env protein, except for a mutant with a combination of variable loop deletions and deglycosylation mutations. Our study suggests that modified HIV Env proteins with reduced glycosylation in domains surrounding the CD4 binding site or variable loop-deleted mutants expose important neutralizing epitopes at higher levels than wild type and may provide novel vaccine immunogens.

Chemotherapeutic efficacy of praziquantel in rats with protective immunity to Clonorchis sinensis infection

OBJECTIVE

To study the synergic effect of praziquantel (PZQ) and host acquired immunity on Clonorchis sinensis.

METHODS

Acquired immunity to C. sinensis was induced by immunization with crude adult worm antigen (AW Ag) and excretory-secretory antigen (ES Ag) or infection with C. sinensis metacercariae. The effect was assessed by the worm reduction rate compared with the control groups after challenge infection with 50 metacercariae and treated orally with a subcurative dose of praziquantel (50 mg/kg). Significant test was performed by analysis of variance (ANOVA) and Npar1 way Kruskal-Wallis test. All calculations were performed by PC-SAS system.

RESULTS

1. PZQ was more effective against C. sinensis larvae than against adult worms in the control (P < 0.001), ES Ag (P < 0.01) or crude AW Ag immunization group (P < 0.001). 2. As compared with the control, the worm reduction rate after challenge infection was significantly higher (P < 0.001) in ES Ag immunized group (35.6%) and metacercaria infection group (97.5%) and less in crude AW Ag group (23.4%). The PZQ efficacy was significantly enhanced in ES Ag immunized group.

CONCLUSION

The efficacy of PZQ against C. sinensis could be synergically enhanced in rats by inducing host acquired immunity.

Efficacy of flubendazole and albendazole against Trichinella spiralis in mice

Efficacy of flubendazole and albendazole against Trichinella spiralis in mice were studied. ICR mice were experimentally infected with Trichinella spiralis and treated with either flubendazole (FBZ) or albendazole (ABZ) at four different stages of the parasite life-cycle. Oral administration of either FBZ or ABZ at 20 mg/kg and 50 mg/kg on 2 h, 8 h and 24 h (pre-adult stage) after infection eliminated 94.7-100% of adults as determined at necropsy on day 7 post infection (p.i.) and 96.9-100% of larvae on day 45 p.i. FBZ was more effective than ABZ against adult T. spiralis (at 2 to 6 days p.i.), when treated with a dosage of 20 mg/kg for 5 consecutive days (99.4% and 46.0% reduction with respect to the control group). Against migrating larval T. spiralis, FBZ was more effective than ABZ at 20 mg/kg for five consecutive days (on days 11-15 p.i.), and the reduction rate of recovered larvae were 99.6% (FBZ) and 80.8% (ABZ) respectively. FBZ was more effective against early encapsulated larval T. spiralis (at 21 to 25 days p.i.), than ABZ when both were given at 20 mg/kg for five consecutive days (99.8% and 45.4% reduction, respectively). In conclusion, flubendazole was more effective than albendazole against adult and parenteral stages of Trichinella spiralis in mice.

The infection status of anisakid larvae in marine fish and cephalopods from the Bohai Sea, China and their taxonomical consideration

The infection status of anisakid larvae was examined in 290 marine fish of 25 species and in 108 cephalopods of 3 species purchased in Bayuquan region, Yingko city nearby the coast of the Bohai Sea from may to August 1992. A total of 7,327 larvae were collected from 156 fish of 19 species and 8 squids of one species. The 3rd-stage larvae of Anisakis simplex were collected from 121 fish (63.4%) of 15 species (N = 191) and from 8 squids (14.8%) of one species (N = 54), and they were total, 5,992 (81.8%). Out of remaining 1,335 larvae, 154 (2.1%) were classified as Thynnascaris type B from 23 fish of 4 species, 1,013 (13.8%) as Thynnascaris type C from 79 fish of 13 species. 164 (2.2%) as Hysterothylacium China type V from 20 fish of 4 species, 3 (0.04%) as Raphidascaris from 3 fish of 2 species and one was Pseudoterranova decipiens larva.