Neuronal MeCP2 in the dentate gyrus regulates mossy fiber sprouting of mice with temporal lobe epilepsy.

Sprouting of mossy fibers, one of the most consistent findings in tissue from patients with mesial temporal lobe epilepsy, exhibits several uncommon axonal growth features and has been considered a paradigmatic example of circuit plasticity that occurs in the adult brain. Clarifying the mechanisms responsible may provide new insight into epileptogenesis as well as axon misguidance in the central nervous system. Methyl-CpG-binding protein 2 (MeCP2) binds to methylated genomic DNA to regulate a range of physiological functions implicated in neuronal development and adult synaptic plasticity. However, exploring the potential role of MeCP2 in the documented misguidance of axons in the dentate gyrus has not yet been attempted. In this study, a status epilepticus-induced decrease of neuronal MeCP2 was observed in the dentate gyrus (DG). An essential regulatory role of MeCP2 in the development of functional mossy fiber sprouting (MFS) was confirmed through stereotaxic injection of a recombinant adeno-associated virus (AAV) to up- or down-regulate MeCP2 in the dentate neurons. Chromatin immunoprecipitation sequencing (ChIP-seq) was performed to identify the binding profile of native MeCP2 using micro-dissected dentate tissues. In both dentate tissues and HT22 cell lines, we demonstrated that MeCP2 could act as a transcription repressor on miR-682 with the involvement of the DNA methylation mechanism. Further, we found that miR-682 could bind to mRNA of phosphatase and tensin homolog (PTEN) in a sequence specific manner, thus leading to the suppression of PTEN and excessive activation of mTOR. This study therefore presents a novel epigenetic mechanism by identifying MeCP2/miR-682/PTEN/mTOR as an essential signal pathway in regulating the formation of MFS in the temporal lobe epileptic (TLE) mice. SIGNIFICANCE STATEMENT: Understanding the mechanisms that regulate axon guidance is important for a better comprehension of neural disorders. Sprouting of mossy fibers, one of the most consistent findings in patients with mesial temporal lobe epilepsy, has been considered a paradigmatic example of circuit plasticity in the adult brain. Although abnormal regulation of DNA methylation has been observed in both experimental rodents and humans with epilepsy, the potential role of DNA methylation in this well-documented example of sprouting of dentate axon remains elusive. This study demonstrates an essential role of methyl-CpG-binding protein 2 in the formation of mossy fiber sprouting. The underlying signal pathway has been also identified. The data hence provide new insight into epileptogenesis as well as axon misguidance in the central nervous system.

Isoflurane-induced reduction in neurogenesis derived from the tertiary dentate matrix.

Anesthetics-induced disruption of dentate neurogenesis in the young brain is strongly suggested to contribute to delayed neurocognitive deficit. In postnatal rodents, the neurogenesis of the dentate gyrus (DG) is sequentially derived from the secondary dentate matrix, tertiary dentate matrix and subgranular zone (SGZ). However, the effects of anesthetics on the dentate neurogenesis derived from specific sites are poorly understood. To trace the new cells generated from the postnatal secondary dentate matrix, peak stage of the tertiary dentate matrix and early stage of the SGZ after isoflurane exposure, mice at postnatal day 1 (P1), P7 and P31 were injected with BrdU at 12 h before the exposure. We found that isoflurane exposure significantly reduced the numbers of proliferating cells (1 day old), immature granule cells (21 days old) or mature granule cells (42 days old) derived from the peak stage of the tertiary dentate matrix and postnatal secondary dentate matrix, but not from the SGZ. Quantitative assessment of BrdU-/BrdU+NeuN-positive cells and cleaved caspase-3 level in the DG indicated that the reduction was correlated with cell loss rather than neuronal differentiation. Mechanistically, we demonstrated that the PI3K/Akt/GSK-3ß pathway enriched by mRNA-sequencing is a requirement for the isoflurane-induced loss of 1-day-old proliferating cells generated from the tertiary dentate matrix. In addition, this study demonstrated that P1 and P7 mice, but not P31 mice exposure to isoflurane resulted in subsequent deficits in performance of the tasks of the Morris Water Maze.

The characteristics of the urogenital fascia in the retrorectal space based on male cadaveric dissection and its clinical application.

BACKGROUND: The architecture of retrorectal fasciae is complex, as determined by different anatomical concepts. The aim of this study was to examine the anatomical characteristics of the inferomedial extension of the urogenital fascia (UGF) involving the pelvis to explore its relationship with the adjacent fasciae. Furthermore, we have expounded on the clinical application of UGF. METHOD: For our study, we examined 20 adult male pelvic specimens fixed in formalin, including 2 entire pelvic specimens and 18 semipelvic specimens. Our department has performed 466 laparoscopic rectal cancer procedures since January 2020. We reviewed the surgical videos involving UGF preservation and analyzed the anatomy of the UGF. RESULTS: The bilateral hypogastric nerves ran between the visceral and parietal layers of the UGF. The visceral fascia migrated ventrally at the fourth sacral vertebra, which formed the rectosacral fascia together with the fascia propria of the rectum; the parietal layer continually extended to the pelvic diaphragm, terminating at the levator ani muscle. At the third to fourth sacral vertebra level, the two layers constituted the lateral ligaments. CONCLUSION: The double layers of the UGF are vital structures for comprehending the posterior fascia relationship of the rectum. The upper segment between the fascia propria of the rectum and the visceral layer has no evident nerves or blood vessels and is regarded as the " holy plane" for the operation.

The "Y"-shaped Denonvilliers' fascia and its adjacent relationship with the urogenital fascia based on a male cadaveric anatomical study.

BACKGROUND: Controversies regarding the anatomical structure of Denonvilliers' fascia and its relationship with surrounding fasciae have sparked a heated discussion, especially concerning whether Denonvilliers' fascia is multilayered. This study aimed to expound on the anatomical structure of Denonvilliers' fascia and its correlation with the peritoneum from the sagittal view and clarify the complex fascial relationship. METHODS: Our study was performed on 20 adult male pelvic specimens fixed in formalin, including 2 entire pelvic specimens and 18 semipelvic specimens. The local adjacent organs and fasciae were dissected, and Denonvilliers' fascia was observed and removed for histological examination. RESULTS: Denonvilliers' fascia was typically single-layered and tough. On the sagittal plane, the peritoneum constituting the peritoneal reflection and Denonvilliers' fascia formed a "Y" shape. Denonvilliers' fascia originated from the peritoneal reflection, extended along the ventral side of the seminal vesicles and prostate, continuing caudally; its bilateral sides closely connected to the urogenital fascia (UGF) of the pelvic wall. In addition, histology preliminarily indicated that the basal cell layers of the peritoneum and Denonvilliers' fascia were continuous and formed a "Y" shape. Furthermore, the basal cells of the two peritonea extended to Denonvilliers' fascia, creating a fused double-layered structure. Some tiny blood vessels or a network of such vessels extended from the peritoneum to Denonvilliers' fascia. CONCLUSION: Denonvilliers' fascia, the extension of the peritoneum in the pelvic floor, appears as a single-layered "Y"-shape on the sagittal plane. Our study provides new support for the peritoneal fusion theory. Understanding the anatomical characteristics of Denonvilliers' fascia and its relationship with the UGF is of guiding significance for inexperienced colorectal surgeons to conduct rectal cancer surgery.

SQSTM1/p62 regulate breast cancer progression and metastasis by inducing cell cycle arrest and regulating immune cell infiltration.

The autophagy adaptor protein SQSTM1/p62 is overexpressed in breast cancer and has been identified as a metastasis-related protein. However, the mechanism by which SQSTM1/p62 contributes to breast cancer progression and tumor microenvironment remains unclear. This study revealed that silencing SQSTM1/p62 expression suppressed breast cancer progression via regulating cell proliferation and reshaping the tumor microenvironment (TME). Here, we found that SQSTM1/p62 was overexpressed in multiple human cancer tissue types and that was correlated with poor patient overall survival (OS) and disease-free survival (DFS). Moreover, we found that short-hairpin RNA (shRNA)-mediated knockdown of p62 expression significantly inhibited cell proliferation, migration, and invasion, and promoted cell death in vitro, as well as suppressed breast cancer growth and lung metastasis in vivo. In addition, flow cytometry analysis of splenocytes and tumor infiltrating lymphocytes (TILs) indicated that the numbers of CD8α+ interferon (IFN)-γ+ cells (CTLs) and CD4+IFN-γ+ (Th1) cells were increased while those of CD4+IL-4+ (Th2) cells, tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) were decreased. RT-PCR analyses showed that the gene expression of Th1/Th2 cytokines changed in the tumor microenvironment. Silencing SQSTM1/p62 suppressed tumor cell lung metastasis. Together, our results provide strong evidence that silencing tumor cell SQSTM1/p62 inhibited tumor growth and metastasis through cell cycle arrest and TME regulation. This finding provides a novel molecular therapeutic strategy for breast cancer progression and metastasis treatment.

Assisting Role of Pulmonary Hypostasis Phenomenon in Diagnosis of Drowning.

OBJECTIVES: To study the phenomenon of pulmonary hypostasis in corpses of various causes of death, and to explore the potential value of this phenomenon in assisting forensic pathological diagnosis of drowning. METHODS: A total of 235 cases with clear cause of death through systematic autopsy were collected from January 2011 to June 2021 in Guangzhou. According to the location of body discovery, the cases were divided into the water body group (97 cases) and the non-water body group (138 cases), and the water body group was further divided into the water drowning group (90 cases) and the water non-drowning group (7 cases). Non-water body group was further divided into the non-water drowning group (1 case) and the non-water non-drowning group (137 cases). Three senior forensic pathologists independently reviewed autopsy photos to determine whether there was hypostasis in the lungs. The detection rate of pulmonary hypostasis was calculated. RESULTS: The detection rate of pulmonary hypostasis in the water drowning group (90 cases) was 0, and the negative rate was 100%. The detection rate of pulmonary hypostasis in the water non-drowning group (7 cases) was 100% and the negative rate was 0. The detection rate of pulmonary hypostasis in the water body group and in the non-water body group (after excluding 2 cases, 136 cases were calculated) was 7.22% and 87.50%, respectively. There were statistically significant differences in the detection rate of pulmonary hypostasis between water body group and non-water body group, and between water drowning group and water non-drowning group (P<0.05). CONCLUSIONS: The disappearance of pulmonary hypostasis can be used as a specific cadaveric sign to assist in the forensic pathological diagnosis of drowning.

Identification of microRNA/target gene in the dentate gyrus of 7­day­old mice following isoflurane exposure.

Studies on rodents and nonhuman primates suggest that exposure to anesthetics, particularly in the young brain, is associated with neuronal apoptosis as well as hippocampal­dependent cognitive dysfunction. Disruption of the development of dentate gyrus may play an important role in anesthetics­induced neurotoxicity. However, the anesthetics triggered molecular events in the dentate gyrus of the developing brain are poorly understood. By integrating two independent data sets obtained from miRNA­seq and mRNA­seq respectively, this study aims to profile the network of miRNA and potential target genes, as well as relevant events occurring in the dentate gyrus of isoflurane exposed 7­day­old mice. We found that a single four hours exposure to isoflurane yielded 1059 pairs of differently expressed miRNAs/target genes in the dentate gyrus. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis further indicates that dysregulated miRNAs/target genes have far­reaching effects on the cellular pathophysiological events, such as cell apoptosis, axon development, and synaptic transmission. Our results would greatly broaden our functional understanding of the role of miRNA/target gene in the context of anesthetics­induced neurotoxicity.

Neuronal Glypican4 promotes mossy fiber sprouting through the mTOR pathway after pilocarpine-induced status epilepticus in mice.

In temporal lobe epilepsy (TLE), abnormal axon guidance and synapse formation lead to sprouting of mossy fibers in the hippocampus, which is one of the most consistent pathological findings in patients and animal models with TLE. Glypican 4 (Gpc4) belongs to the heparan sulfate proteoglycan family, which play an important role in axon guidance and excitatory synapse formation. However, the role of Gpc4 in the development of mossy fibers sprouting (MFS) and its underlying mechanism remain unknown. Using a pilocarpine-induced mice model of epilepsy, we showed that Gpc4 expression was significantly increased in the stratum granulosum of the dentate gyrus at 1 week after status epilepticus (SE). Using Gpc4 overexpression or Gpc4 shRNA lentivirus to regulate the Gpc4 level in the dentate gyrus, increased or decreased levels of netrin-1, SynI, PSD-95, and Timm score were observed in the dentate gyrus, indicating a crucial role of Gpc4 in modulating the development of functional MFS. The observed effects of Gpc4 on MFS were significantly antagonized when mice were treated with L-leucine or rapamycin, an agonist or antagonist of the mammalian target of rapamycin (mTOR) signal, respectively, demonstrating that mTOR pathway is an essential requirement for Gpc4-regulated MFS. Additionally, the attenuated spontaneous recurrent seizures (SRSs) were observed during chronic stage of the disease by suppressing the Gpc4 expression after SE. Altogether, our findings demonstrate a novel control of neuronal Gpc4 on the development of MFS through the mTOR pathway after pilocarpine-induced SE. Our results also strongly suggest that Gpc4 may serve as a promising target for antiepileptic studies.

Thymosin ß4 reverses phenotypic polarization of glial cells and cognitive impairment via negative regulation of NF-κB signaling axis in APP/PS1 mice.

BACKGROUND: Thymosin ß4 (Tß4) is the most abundant member of the ß-thymosins and plays an important role in the control of actin polymerization in eukaryotic cells. While its effects in multiple organs and diseases are being widely investigated, the safety profile has been established in animals and humans, currently, little is known about its influence on Alzheimer's disease (AD) and the possible mechanisms. Thus, we aimed to evaluate the effects and mechanisms of Tß4 on glial polarization and cognitive performance in APP/PS1 transgenic mice. METHODS: Behavior tests were conducted to assess the learning and memory, anxiety and depression in APP/PS1 mice. Thioflavin S staining, Nissl staining, immunohistochemistry/immunofluorescence, ELISA, qRT-PCR, and immunoblotting were performed to explore Aß accumulation, phenotypic polarization of glial cells, neuronal loss and function, and TLR4/NF-κB axis in APP/PS1 mice. RESULTS: We demonstrated that Tß4 protein level elevated in all APP/PS1 mice. Over-expression of Tß4 alone alleviated AD-like phenotypes of APP/PS1 mice, showed less brain Aß accumulation and more Insulin-degrading enzyme (IDE), reversed phenotypic polarization of microglia and astrocyte to a healthy state, improved neuronal function and cognitive behavior performance, and accidentally displayed antidepressant-like effect. Besides, Tß4 could downregulate both TLR4/MyD88/NF-κB p65 and p52-dependent inflammatory pathways in the APP/PS1 mice. While combination drug of TLR4 antagonist TAK242 or NF-κB p65 inhibitor PDTC exerted no further effects. CONCLUSIONS: These results suggest that Tß4 may exert its function by regulating both classical and non-canonical NF-κB signaling and is restoring its function as a potential therapeutic target against AD.

Identification of microRNA-target genes in mice hippocampus at 1 week after pilocarpine-induced status epilepticus.

MicroRNAs (miRNA) are believed to play a crucial role in the cause and treatment of temporal lobe epilepsy (TLE) by controlling gene expression in different stages of the disease. To investigate role of miRNA in the latent stage following status epilepticus, we first compared microRNA expression profiles in mice hippocampus at 1 week after pilocarpine-induced status epilepticus (SE) vs. controls in hippocampal tissues using Exiqon miRCURY LNA™ miRNAs Array. Then, the target genes of altered miRNAs were predicted using both TargetScan 7.1 and miRDB V5, and were further selected by intersecting with another independent mRNA expression profile dataset from the samples at the same time point. We found out 14 common genes as down miRNA target (up-mRNA) and 4 common genes as up miRNA target (down mRNA) in SE mice. miR-669m-3p-TRHR (thyrotropin releasing hormone receptor), miR-669m-3p-B3galt2 (ß-1,3-Galactosyltransferase 2), miR-105-PDPN (Podoplanin) and miR-883b-3p-CLEC-2 (C-type-lectin-like-2) were found to be potential molecular mechanisms to modulate the calcium signaling pathway, glycosylation pathways and chemokine mediated inflammatory processes in mice hippocampus at 1 week after pilocarpine-induced SE, respectively. Our results offered potential novel insights into the cellular events in the mice hippocampus mediated by miRNASs-target genes that shape SE-evoked epileptogenesis.

PNU282987 alleviates Aß-induced anxiety and depressive-like behaviors through upregulation of α7nAChR by ERK-serotonin receptors pathway.

Patients with Alzheimer's disease often undergo anxiety and depression. Our previous studies have shown that α7nAChR protects against Aß-induced neurotoxicity via downregulation of p38 and JNK MAPKs, but the role of α7nAChR on Aß-induced anxiety and depressive-like behaviors and the effect of α7nAChR on the regulation of MAPKs pathways remain unknown. To examine the effects of α7nAChR and MAPKs pathways on Aß-induced anxiety and depression-like behaviors and to explore their relationships between them, elevated plus maze, open field and forced swim tests were performed. Protein levels of 5-HT1A receptor, 5-HT2C receptor, α7nAChR, t-ERK1/2 and p-ERK1/2 in the amygdala were analyzed by western blotting and immunostaining. Our study found out that Aß oligomers induced anxiety and depression-like behaviors in C56BL/6 mice with open field, elevated plus maze and forced swim tests. However, activation of α7nAChR or inhibition of ERK pathways showed significant antidepressant and anxiolytic-like effects on Aß-injected mice. Moreover, Aß significantly decreased the level of 5-HT1A receptor but increased the level of 5-HT2C receptor in the basolateral amygdala. Treatment with α7nAChR agonist PNU282987 or ERK inhibitor U0126 reversed Aß-induced 5-HT1A and 5-HT2C receptor changes. Moreover, activation of α7nAChR inhibited ERK pathway in the amygdala of Aß1-42-injected mice. Our study provides a new insight into the mechanism of α7nAChR in Aß-induced depression and anxiety-related symptoms through the regulation of ERK1/2 pathway and the potential association with serotonin receptors. Together, our data suggests that α7nAChR is protective against Aß-induced anxiety and depression-like behaviors in mice.

Pulmonary Staphylococcus aureus infection regulates breast cancer cell metastasis via neutrophil extracellular traps (NETs) formation.

The formation of neutrophil extracellular traps (NETs) was recently identified as one of the most important processes for the maintenance of host tissue homeostasis in bacterial infection. Meanwhile, pneumonia infection has a poor effect on cancer patients receiving immunotherapy. Whether pneumonia-mediated NETs increase lung metastasis remains unclear. In this study, we identified a critical role for multidrug-resistant Staphylococcus aureus infection-induced NETs in the regulation of cancer cell metastasis. Notably, S. aureus triggered autophagy-dependent NETs formation in vitro and in vivo and increased cancer cell metastasis. Targeting autophagy effectively regulated NETs formation, which contributed to the control of cancer metastasis in vivo. Moreover, the degradation of NETs by DNase I significantly suppresses metastasis in lung. Our work offers novel insight into the mechanisms of metastasis induced by bacterial pneumonia and provides a potential therapeutic strategy for pneumonia-related metastasis.

P. aeruginosa Mediated Necroptosis in Mouse Tumor Cells Induces Long-Lasting Systemic Antitumor Immunity.

Necroptosis is a form of programmed cell death (PCD) characterized by RIP3 mediated MLKL activation and increased membrane permeability via MLKL oligomerization. Tumor cell immunogenic cell death (ICD) has been considered to be essential for the anti-tumor response, which is associated with DC recruitment, activation, and maturation. In this study, we found that P. aeruginosa showed its potential to suppress tumor growth and enable long-lasting anti-tumor immunity in vivo. What's more, phosphorylation- RIP3 and MLKL activation induced by P. aeruginosa infection resulted in tumor cell necrotic cell death and HMGB1 production, indicating that P. aeruginosa can cause immunogenic cell death. The necrotic cell death can further drive a robust anti-tumor response via promoting tumor cell death, inhibiting tumor cell proliferation, and modulating systemic immune responses and local immune microenvironment in tumor. Moreover, dying tumor cells killed by P. aeruginosa can catalyze DC maturation, which enhanced the antigen-presenting ability of DC cells. These findings demonstrate that P. aeruginosa can induce immunogenic cell death and trigger a robust long-lasting anti-tumor response along with reshaping tumor microenvironment.

Hydrophilic/hydrophobic characters of antimicrobial peptides derived from animals and their effects on multidrug resistant clinical isolates.

Multidrug resistant (MDR) pathogen infections are serious threats to hospitalized patients because of the limited therapeutic options. A novel group of antibiotic candidates, antimicrobial peptides (AMPs), have recently shown powerful activities against both Gram-negative and Gram-positive bacteria. Unfortunately, the viability of using these AMPs in clinical settings remains to be seen, since most still need to be evaluated prior to clinical trials and not all of AMPs are potent against MDR clinical isolates. To find a connection between the characteristics of several of these AMPs and their effects against MDR pathogens, we selected 14 AMPs of animal origin with typical structures and evaluated their in vitro activities against clinical strains of extensive drug-resistant Acinetobacter baumannii, methicillin-resistant Staphylococcus aureus, extended spectrum ß-lactamase-producing Pseudomonas aeruginosa and extended spectrum ß-lactamase-producing Escherichia coli. Our results showed that these peptides' hydrophilic/hydrophobic characteristics, rather than their secondary structures, may explain their antibacterial effects on these clinical isolates. Peptides that are amphipathic along the longitudinal direction seemed to be effective against Gram-negative pathogens, while peptides with hydrophilic terminals separated by a hydrophobic intermediate section appeared to be effective against both Gram-negative and Gram-positive pathogens. Among these, cathelicidin-BF was found to inhibit all of the Gram-negative pathogens tested at dosages of no more than 16 mg/L, killing a pandrug-resistant A. baumannii strain within 2 h at 4×MICs and 4 h at 2×MICs. Tachyplesin III was also found capable of inhibiting all Gram-negative and Gram-positive pathogens tested at no more than 16 mg/L, and similarly killed the same A. baumannii strain within 4 h at 4×MICs and 2×MICs. These results suggest that both cathelicidin-BF and tachyplesin III are likely viable targets for the development of AMPs for clinical uses.

[Biological effects of immune serum from fusion protein of beta-amyloid peptide and HbcAg/MIR on AD transgeneic cells].

OBJECTIVE: To investigate the expression of fusion protein c-Abeta-c, a fusion protein from the beta amyloid peptide (Abeta) and the Hepatitis B core antigen/ Major immunodominant region (HbcAg/MIR), in the BL21/pET28 prokaryotic expression system and to immunize mice with the expressed fusion protein and evaluate the immunogenicity and biological effects of the serum in vitro. METHODS: The recombinant prokaryotic expression plasmid PET-28a /c-Abeta-c was constructed by molecular cloning technique and the c-Abeta-c fusion gene expression was induced in E. coli BL21 by isopropyl-1-thio-b-Dgalactopyranoside (IPTG). The expressed fusion protein was analyzed by SDS-PAGE. Intraperitoneal injection (i.p.) of the purified c-Abeta-c fusion protein was given to the BALB/c mice. The anti-Abeta effect of the immune serum was detected by indirect ELISA. The biological effect of the immune serum on Alzheimer's disease (AD) transgeneic cells was assessed by MTT assay and flow cytometer. RESULTS: The c-Abeta-c fusion protein was found in the sediment of the isolated bacteria. The expressed protein comprised more than 30% of the total proteins in the bacteria sediment. The anti-Abeta antibody in the serum of the immunized mice reached 1:16000. The antiserum reduced the cytotoxicity of Abeta peptide in the AD transgeneic cells and significantly decreased the apoptosis of cells. CONCLUSION: The c-Abeta-c fusion protein has good Abeta immunogenicity and the animal immune serum efficiently inhibits the cytotoxicity of Abeta peptide.

[Protective effect of adeno-associated viral vector-mediated expression of human brain-derived neurotrophic factor in rat neurons against beta-amyloid-induced Alzheimer's disease in vitro].

OBJECTIVE: To achieve expression of human brain-derived neurotrophic factor (hBDNF) mediated by recombinant adeno-associated virus (rAAV) and explore the mechanism of its neuroprotective effects in rat neurons against beta-amyloid-induced Alzheimer's disease. METHODS: Using molecular cloning technique, rAAV vector containing hBDNF gene (AAV-hBDNF) was constructed to transfect SD rat hippocampal neurons exposed to beta-amyloid treatment. The changes in cell apoptosis were observed by MTT assay and flow cytometry, and the expression of hBDNF and Bcl-2 protein were determined by immunocytochemical staining. Laser scanning confocal microscopy (LSCM) was used to observe the changes of [Ca(2+)](i). RESULTS: The cultured rat hippocampal neurons were effectively transfected with AAV-hBDNF and expression of BDNF protein was obviously increased. hBNDF expression showed significant protective effects against beta-amyloid-induced neuronal damage, and the expression of Bcl-2 protein was increased significantly and the balance of [Ca(2+)](i) was maintained in BDNF-treated cells with beta-amyloid exposure. CONCLUSION: hBDNF expression can effectively protect cultured rat hippocampal cells from beta-amyloid-induced apoptosis through inhibiting the intracellular calcium overload and increasing the expression of Bcl-2 protein.

Production in Pichia pastoris and characterization of genetic engineered chimeric HBV/HEV virus-like particles.

OBJECTIVE: To investigate the presentation of a neutralization epitope-containing peptide antigen of hepatitis E virus (HEV) on chimeric virus-like particles (VLPs) of hepatitis B surface antigen (HBsAg). METHODS: The gene fragment corresponding to amino acids (aa) 551-607 (HEnAg) of HEV capsid protein, which contains the only neutralization epitope identified to date, was fused via a synthetic glycine linker in frame with the gene of HBsAg. The resulted fusion gene was then integrated through transformation into the genome of Pichia pastoris under the control of a methanol-induced alcohol oxidase 1 (AOX1) promoter and expressed intracellularly. The expression products in the soluble cell extracts were characterized by Western blot, ELISA, CsCl density gradient analysis, and electron microscopic visualization. RESULTS: The novel fusion protein incorporating HBsAg and the neutralization epitope-containing HEnAg was expressed successfully in Pichia pastoris with an expected molecular weight of approximately 32 kD. It was found to possess the ability to assemble into chimeric HBV/HEV VLPs with immunological physical and morphological characteristics akin to HBsAg particles. Not only did the chimeric VLPs show high activity levels in a HBsAg particle-specific ELISA but they were also strongly immunoreactive with hepatitis E (HE) positive human serum in a HEV specific ELISA, indicating that HEnAg peptide fragments were exposed on VLP surfaces and would be expected to be readily accessible by cells and molecules of the immune system. Similarity between chimeric VLPs to highly immunogenic HBsAg particles may confer good immunogenicity on surface-displayed HEnAg. CONCLUSION: The chimeric HBV/HEV VLPs produced in this study may have potential to be a recombinant HBV/HEV bivalent vaccine candidate.

[Construction of a recombinant human adenovirus expressing the ORF2 antigen of HEV and immunization of mice by mucosal system].

OBJECTIVE: To construct a replication-defective recombinant adenovirus expressing the ORF2 (112-660aa) antigen of hepatitis E virus (HEV) and evaluate its immunization effect in BALB/c mice by mucosal inoculation. METHODS: The HEV ORF2 gene encoding for 112-660aa was amplified from plasmid pUC-HEV and inserted into the transfer vector pTrack-CMV. The recombinant plasmid and adenoviral backbone plasmid pAdEasy-1 were co-transformed into E. coli strain BJ5183. Taking the advantage of the high efficient homologous recombination machinery presented in bacteria, the recombinant adenovirus backbone plasmid was generated in BJ5183, and then was transfected into 293 cells. Recombinant Adenoviruses were propagated in 293 cells with high titers. 8-week-old BALB/c mice were inoculated intraperitoneally and intranasally with 10(7) pfu recombinant adenovirus each on weeks 0, 3, 5, 7, 10. RESULTS: Both groups of mice induced humoral IgG immune response with the highest titers 1:1,000 and 1:10,000 each. Only the group inoculated intranasally could induce mucosal IgA immune response. CONCLUSIONS: The adenoviral recombinant can stimulate specific humoral and mucosal immune response in mice and is potentially to be used as a candidate vaccine for the treatment of HEV infection.

[Refolding and purification of the huGM-CSF(9-127)-IL-6(29-184) fusion protein].

The huGM-CSF(9-127)-IL-6(29-184) fusion protein was precipitated on column when being purified by Q Sepharose H.P. ion exchange chromatography after renaturation by dilution. To solve this problem, a novel purification and refolding strategy was adopted. Inclusion bodies was first purified by Q Sepharose H.P. ion exchange in 8 mol/L urea, followed by in situ refolding on column by Sephacryl S-200. Renatured fusion protein was obtained in a purity of more than 95%. It was showed that the method of refolding on gel filtration column is efficient, with relative refolding rate at 80%. By the whole procedure, refolding and purification of recombinant protein can be performed within one day. This strategy is also promising to be applied in large scale purification and refolding of recombinant protein from inclusion bodies in E. coli.