Chimeric Porcine Parvovirus VP2 Virus-like Particles with Epitopes of South African Serotype 2 Foot-and-Mouth Disease Virus Elicits Specific Humoral and Cellular Responses in Mice

Southern Africa Territories 2 (SAT2) foot-and-mouth disease (FMD) has crossed long-standing regional boundaries in recent years and entered the Middle East. However, the existing vaccines offer poor cross-protection against the circulating strains in the field. Therefore, there is an urgent need for an alternative design approach for vaccines in anticipation of a pandemic of SAT2 Foot-and-mouth disease virus (FMDV). The porcine parvovirus (PPV) VP2 protein can embed exogenous epitopes into the four loops on its surface, assemble into virus-like particles (VLPs), and induce antibodies and cytokines to PPV and the exogenous epitope. In this study, chimeric porcine parvovirus VP2 VLPs (chimeric PPV-SAT2-VLPs) expressing the T-and/or B-cell epitopes of the structural protein VP1 of FMDV SAT2 were produced using the recombinant pFastBac™ Dual vector of baculoviruses in Sf9 and HF cells We used the Bac-to-Bac system to construct the recombinant baculoviruses. The VP2-VLP--SAT2 chimeras displayed chimeric T-cell epitope (amino acids 21-40 of VP1) and/or the B-cell epitope (amino acids 135-174) of SAT FMDV VP1 by substitution of the corresponding regions at the N terminus (amino acids 2-23) and/or loop 2 and/or loop 4 of the PPV VP2 protein, respectively. In mice, the chimeric PPV-SAT2-VLPs induced specific antibodies against PPV and the VP1 protein of SAT2 FMDV. The VP2-VLP-SAT2 chimeras induced specific antibodies to PPV and the VP1 protein specific epitopes of FMDV SAT2. In this study, as a proof-of-concept, successfully generated chimeric PPV-VP2 VLPs expressing epitopes of the structural protein VP1 of FMDV SAT2 that has a potential to prevent FMDV SAT2 and PPV infection in pigs.

Establishment of a secondary infection laboratory model of Echinococcus shiquicus metacestode using BALB/c mice and Mongolian jirds (Meriones unguiculatus)

Echinococcus shiquicus is peculiar to the Qinghai–Tibet plateau of China. Research on this parasite has mainly focused on epidemiological surveys and life cycle studies. So far, limited laboratory studies have been reported. Here, experimental infection of E. shiquicus metacestode in BALB/c mice and Mongolian jirds (Meriones unguiculatus) was carried out to establish alternative laboratory animal models. Intraperitoneal inoculation of metacestode material containing protoscoleces (PSCs) obtained from infected plateau pikas were conducted on BALB/c mice. Furthermore, metacestode material without PSCs deriving from infected BALB/c mice was intraperitoneally inoculated to Mongolian jirds. Experimental animals were dissected for macroscopic and histopathological examination. The growth of cysts in BALB/c mice was infiltrative, and they invaded the murine entire body. Most of the metacestode cysts were multicystic, but a few were unilocular. The cysts contained sterile vesicles, which had no PSCs. The metacestode materials were able to successfully infect new mice. In the jirds model, E. shiquicus cysts were typically formed freely in the peritoneal cavity; the majority of these cysts were free while a small portion adhered loosely to nearby organs. The proportion of fertile cysts was high, and contained many PSCs. The PSCs produced in Mongolian jirds also successfully infected new ones, which confirms that jirds can serve as an alternative experimental intermediate host. In conclusion, a laboratory animal infection was successfully established for E. shiquicus using BALB/c mice and Mongolian jirds. These results provide new models for the in-depth study of Echinococcus metacestode survival strategy, host interactions and immune escape mechanism.

Understanding pathogen–host interplay by expression profiles of lncRNA and mRNA in the liver of Echinococcus multilocularis-infected mice

Almost all Echinococcus multilocularis (Em) infections occur in the liver of the intermediate host, causing a lethal zoonotic helminthic disease, alveolar echinococcosis (AE). However, the long non-coding RNAs (lncRNAs) expression profiles of the host and the potential regulatory function of lncRNA during Em infection are poorly understood. In this study, the profiles of lncRNAs and mRNAs in the liver of mice at different time points after Em infection were explored by microarray. Thirty-one differentially expressed mRNAs (DEMs) and 68 differentially expressed lncRNAs (DELs) were found continuously dysregulated. These DEMs were notably enriched in “antigen processing and presentation”, “Th1 and Th2 cell differentiation” and “Th17 cell differentiation” pathways. The potential predicted function of DELs revealed that most DELs might influence Th17 cell differentiation and TGF-β/Smad pathway of host by trans-regulating SMAD3, STAT1, and early growth response (EGR) genes. At 30 days post-infection (dpi), up-regulated DEMs were enriched in Toll-like and RIG-I-like receptor signaling pathways, which were validated by qRT-PCR, Western blotting and downstream cytokines detection. Furthermore, flow cytometric analysis and serum levels of the corresponding cytokines confirmed the changes in cell-mediated immunity in host during Em infection that showed Th1 and Th17-type CD4+ T-cells were predominant at the early infection stage whereas Th2-type CD4+ T-cells were significantly higher at the middle/late stage. Collectively, our study revealed the potential regulatory functions of lncRNAs in modulating host Th cell subsets and provide novel clues in understanding the influence of Em infection on host innate and adaptive immune response.

Dose-dependent effect of glucose on GLP-1 secretion involves sweet taste receptor in isolated perfused rat ileum [Rapid Communication]

Luminal glucose is an important stimulus for glucagon-like peptide 1 (GLP-1) secretion from intestinal endocrine cells. However, the effects of luminal glucose concentration on GLP-1 secretion remain unknown. In this study, we investigated the effect of luminal glucose concentrations (3.5, 5, 10, 15, and 20 mmol/L) on GLP-1 secretion from isolated perfused rat ileum. Results showed that the perfusate glucose concentration dose-dependently stimulated GLP-1 secretion from isolated perfused rat ileum, which was eliminated by the sweet taste receptor inhibitor gurmarin (30 μg/mL), but not inhibited by phloridzin (1 mmol/L), a Na⁺-coupled glucose transporters inhibitor. We conclude that luminal glucose induced GLP-1 secretion from perfused rat ileum in a concentration-dependent manner. This secretion was mediated by sweet taste receptor transducing signal for GLP-1 release on the gut of rat.

[The etiology of impotence in 327 diabetic male adults]

OBJECTIVE

To investigate the etiology of impotence in diabetic male adults.

METHODS

327 diabetic men aged 20 - 70 years were interviewed; 129 (39.6%) of them complained of impotence. All the 129 patients were initially evaluated by diabetologists and then underwent psychosexual assessment by psychiatrists. In addition, evaluation for retinopathy, neuropathy, vascular disease and sex hormone level was carried out.

RESULTS

The 327 diabetic patients were divided into four age ranges 25 - 34, 35 - 44, 45 - 54, and 55 - 70. The frequency of diabetic impotence in these groups was 9.7%, 34.2%, 48.0%, 62.7% respectively. Neuropathy was found in 79 (61.2%), psychogenic factor contributed in 66 (51.2%), vascular factor was present in 31 (24.0%), leakage of penile venous cavernosa occurred in 5 (3.9%), and treatment with impotence- related medications was the contributing factor in 2 (1.6%). There are significant differences of glycosylated hemoglobin, peripheral neuropathy, autonomic neuropathy, and proliferative retinopathy between impotent and potent diabetic patients. The degree of psychological problem is more serious in the diabetic impotent patients than in potent patients according to Minnesota multiphasic personality inventory (MMPI) test. No significant difference was found in smoking, alcohol and plasma testosterone level.

CONCLUSION

The etiology of diabetic impotence is multifactorial. Neuropathy is the main cause, but vascular and psychological factors also contribute to it significantly.