The Influence of Long-Term Dietary Intake of Titanium Dioxide Particles on Elemental Homeostasis and Tissue Structure of Mouse Organs.

Background: Titanium dioxide (TiO2), consisting of nanoparticles and sub-microparticles, were widely used as food additive and consumed by people every day, which has aroused a public safety concern. Some studies showed TiO2 can be absorbed by intestine and then distributed to different tissues after oral intake, which is supposed to affect the content of various elements in the body whereas led to tissue damage. However, knowledge gaps still exist in the impact of TiO2 on the disorder of elemental homeostasis. Thus, this study aimed to explore the oral toxicity of TiO2 by assessing its influence on elemental homeostasis and tissues injury. Method: ICR mice were fed with normal feed, TiO2 nanoparticles (NPs)-mixed feed or TiO2 submicron particles (MPs)-mixed feed (1% mass fraction TiO2 NPs or MPs were mixed in commercial pellet diet) for 1, 3, and 6 months. Particles used in this study were characterized. The distribution of Ti and other 23 elements, the correlation among elements, and pathological change in the liver, kidney, spleen and blood cells of the mice was determined. Result: Ti accumulation only appeared in blood cells of mice treated with TiO2 MPs-mixed feed for 6 months, but TiO2 cause 12 kinds of elements (boron, vanadium, iron, cobalt, copper, zinc, selenium, sodium, calcium, magnesium, silicon, phosphorus) content changed in organ tissue. The changed kinds of elements in blood cells (6 elements), liver (7 elements) or kidney (6 elements) were more than in the spleen (1 element). The TiO2 NPs induced more elements changed in blood cells and liver, and the TiO2 MPs induced more elements changed in kidney. Significantly positive correlation between Ti and other elements was found in different organs except the liver. Organ injuries caused by TiO2 NPs were severer than TiO2 MPs. Liver exhibited obvious pathological damage which became more serious with the increase of exposure time, while kidney and spleen had slight damages. Conclusion: These results indicated long-time dietary intake of TiO2 particles could induce element imbalance and organ injury. The liver displayed more serious change than other organs, especially under the treatment with TiO2 NPs. Further research on the oral toxicity of TiO2 NPs should pay more attention to the health effects of element imbalances using realistic exposure methods.

Tactile modulation of memory and anxiety requires dentate granule cells along the dorsoventral axis.

Touch can positively influence cognition and emotion, but the underlying mechanisms remain unclear. Here, we report that tactile experience enrichment improves memory and alleviates anxiety by remodeling neurons along the dorsoventral axis of the dentate gyrus (DG) in adult mice. Tactile enrichment induces differential activation and structural modification of neurons in the dorsal and ventral DG, and increases the presynaptic input from the lateral entorhinal cortex (LEC), which is reciprocally connected with the primary somatosensory cortex (S1), to tactile experience-activated DG neurons. Chemogenetic activation of tactile experience-tagged dorsal and ventral DG neurons enhances memory and reduces anxiety respectively, whereas inactivation of these neurons or S1-innervated LEC neurons abolishes the beneficial effects of tactile enrichment. Moreover, adulthood tactile enrichment attenuates early-life stress-induced memory deficits and anxiety-related behavior. Our findings demonstrate that enriched tactile experience retunes the pathway from S1 to DG and enhances DG neuronal plasticity to modulate cognition and emotion.

Cell type-differential modulation of prefrontal cortical GABAergic interneurons on low gamma rhythm and social interaction.

Prefrontal GABAergic interneurons (INs) are crucial for social behavior by maintaining excitation/inhibition balance. However, the underlying neuronal correlates and network computations are poorly understood. We identified distinct firing patterns of prefrontal parvalbumin (PV) INs and somatostatin (SST) INs upon social interaction. Moreover, social interaction closely correlated with elevated gamma rhythms particularly at low gamma band (20 to 50 Hz). Pharmacogenetic inhibition of PV INs, instead of SST INs, reduced low gamma power and impaired sociability. Optogenetic synchronization of either PV INs or SST INs at low gamma frequency improved sociability, whereas high gamma frequency or random frequency stimulation had no effect. These results reveal a functional differentiation among IN subtypes and suggest the importance of low gamma rhythms in social interaction behavior. Furthermore, our findings underscore previously unrecognized potential of SST INs as therapeutic targets for social impairments commonly observed in major neuropsychiatric disorders.

REBACIN® as a noninvasive clinical intervention for high-risk human papillomavirus persistent infection.

The development of highly sensitive HPV-genotyping tests has opened the possibility of treating HPV-infected women before high-grade lesions appear. The lack of efficient intervention for persistent high-risk HPV infection necessitates the need for development of novel therapeutic strategy. Here we demonstrate that REBACIN®, a proprietary antiviral biologics, has shown potent efficacy in the clearance of persistent HPV infections. Two independent parallel clinical studies were investigated, which a total of 199 patients were enrolled and randomly divided into a REBACIN®-test group and a control group without treatment. The viral clearance rates for the REBACIN® groups were 61.5% (24/39) and 62.5% (35/56), respectively, for the two independent parallel studies. In contrast, the nontreatment groups showed self-clearance rates at 20.0% (8/40) and 12.5% (8/64). We further found that REBACIN® was able to significantly repress the expression of HPV E6 and E7 oncogenes in TC-1 and Hela cells. The two viral genes are well known for the development of high-grade premalignancy lesion and cervical cancer. In a mouse model, REBACIN® was indicated to notably suppress E6/E7-induced tumor growth, suggesting E6 and E7 oncogenes as a potential target of REBACIN®. Taken together, our studies shed light into the development of a novel noninvasive therapeutic intervention for clearance of persistent HPV infection with significant efficacy.

ErbB4 deletion in noradrenergic neurons in the locus coeruleus induces mania-like behavior via elevated catecholamines.

Dysfunction of the noradrenergic (NE) neurons is implicated in the pathogenesis of bipolar disorder (BPD). ErbB4 is highly expressed in NE neurons, and its genetic variation has been linked to BPD; however, how ErbB4 regulates NE neuronal function and contributes to BPD pathogenesis is unclear. Here we find that conditional deletion of ErbB4 in locus coeruleus (LC) NE neurons increases neuronal spontaneous firing through NMDA receptor hyperfunction, and elevates catecholamines in the cerebrospinal fluid (CSF). Furthermore, Erbb4-deficient mice present mania-like behaviors, including hyperactivity, reduced anxiety and depression, and increased sucrose preference. These behaviors are completely rescued by the anti-manic drug lithium or antagonists of catecholaminergic receptors. Our study demonstrates the critical role of ErbB4 signaling in regulating LC-NE neuronal function, reinforcing the view that dysfunction of the NE system may contribute to the pathogenesis of mania-associated disorder.

Gamma Oscillation Dysfunction in mPFC Leads to Social Deficits in Neuroligin 3 R451C Knockin Mice.

Neuroligins (NLs) are critical for synapse formation and function. NL3 R451C is an autism-associated mutation. NL3 R451C knockin (KI) mice exhibit autistic behavioral abnormalities, including social novelty deficits. However, neither the brain regions involved in social novelty nor the underlying mechanisms are clearly understood. Here, we found decreased excitability of fast-spiking interneurons and dysfunction of gamma oscillation in the medial prefrontal cortex (mPFC), which contributed to the social novelty deficit in the KI mice. Neuronal firing rates and phase-coding abnormalities were also detected in the KI mice during social interactions. Interestingly, optogenetic stimulation of parvalbumin interneurons in the mPFC at 40 Hz nested at 8 Hz positively modulated the social behaviors of mice and rescued the social novelty deficit in the KI mice. Our findings suggest that gamma oscillation dysfunction in the mPFC leads to social deficits in autism, and manipulating mPFC PV interneurons may reverse the deficits in adulthood.

[Research progress of synaptic vesicle recycling].

Neurotransmission begins with neurotransmitter being released from synaptic vesicles. To achieve this function, synaptic vesicles endure the dynamic "release-recycle" process to maintain the function and structure of presynaptic terminal. Synaptic transmission starts with a single action potential that depolarizes axonal bouton, followed by an increase in the cytosolic calcium concentration that triggers the synaptic vesicle membrane fusion with presynaptic membrane to release neurotransmitter; then the vesicle membrane can be endocytosed for reusing afterwards. This process requires delicate regulation, intermediate steps and dynamic balances. Accumulating evidence showed that the release ability and mobility of synapses varies under different stimulations. Synaptic vesicle heterogeneity has been studied at molecular and cellular levels, hopefully leading to the identification of the relationships between structure and function and understanding how vesicle regulation affects synaptic transmission and plasticity. People are beginning to realize that different types of synapses show diverse presynaptic activities. The steady advances of technology studying synaptic vesicle recycling promote people's understanding of this field. In this review, we discuss the following three aspects of the research progresses on synaptic vesicle recycling: 1) presynaptic vesicle pools and recycling; 2) research progresses on the differences of glutamatergic and GABAergic presynaptic vesicle recycling mechanism and 3) comparison of the technologies used in studying presyanptic vesicle recycling and the latest progress in the technology development in this field.

A novel size-based sorting mechanism of pinocytic luminal cargoes in microglia.

Microglia are the resident immune cells in the CNS and play diverse roles in the maintenance of CNS homeostasis. Recent studies have shown that microglia continually survey the CNS microenvironment and scavenge cell debris and aberrant proteins by phagocytosis and pinocytosis, and that reactive microglia are capable to present antigens to T cells and initiate immune responses. However, how microglia process the endocytosed contents and evoke an immune response remain unclear. Here we report that a size-dependent selective transport of small soluble contents from the pinosomal lumen into lysosomes is critical for the antigen processing in microglia. Using fluorescent probes and water-soluble magnetic nanobeads of defined sizes, we showed in cultured rodent microglia, and in a cell-free reconstructed system that pinocytosed proteins become degraded immediately following pinocytosis and the resulting peptides are selectively delivered to major histocompatibility complex class II (MHC-II) containing lysosomes, whereas undegraded proteins are retained in the pinosomal lumen. This early size-based sorting of pinosomal contents relied on the formation of transient tunnel between pinosomes and lysosomes in a Rab7- and dynamin II-dependent manner, which allowed the small contents to pass through but restricted large ones. Inhibition of the size-based sorting markedly reduced proliferation and cytokine release of cocultured CD4(+) T cells, indicating that the size-based sorting is required for efficient antigen presentation by microglial cells. Together, these findings reveal a novel early sorting mechanism for pinosomal luminal contents in microglial cells, which may explain how microglia efficiently process protein antigens and evoke an immune response.

Development of GABA circuitry of fast-spiking basket interneurons in the medial prefrontal cortex of erbb4-mutant mice.

erbb4 is a susceptibility gene for schizophrenia and ErbB4 signals have been hypothesized to function in a number of cortical developmental processes (Silberberg et al., 2006; Mei and Xiong, 2008). Several recent studies show that the expression of ErbB4 is mainly restricted to GABAergic interneurons (Yau et al., 2003; Woo et al., 2007), specifically, to parvalbumin-positive (PV) fast-spiking (FS) interneurons (Vullhorst et al., 2009; Fazzari et al., 2010), a large majority of which are PV FS basket cells (Kawaguchi, 1995; Taniguchi et al., 2013). However, in the medial prefrontal cortex (mPFC), a brain region that is closely associated with neuropsychiatric disorders including schizophrenia, little is known about the roles of ErbB4 signals during the development of GABAergic circuitry particularly that associated with PV FS basket cells. Here, using molecular genetics, biochemistry, and electrophysiology, we deleted ErbB4 receptors in GABAergic forebrain neurons during the embryonic period and demonstrated that in the mouse mPFC, ErbB4 signals were dispensable for the development of GABAergic synapses by PV FS basket cells. Interestingly, they were required for the final maturation rather than the initial formation of glutamatergic synapses on PV FS basket cells. Furthermore, activity-dependent GABAergic PV FS pyramidal neuron transmission was decreased, whereas activity of pyramidal neurons was increased in KO mice. Together, these data indicate that ErbB4 signals contribute to the development of GABAergic circuitry associated with FS basket cells in component- and stage-dependent manners in the mPFC in vivo, and may suggest a mechanism for neuropsychiatric disorders including schizophrenia.

Effects of perfluorooctane sulfonate on ion channels and glutamate-activated current in cultured rat hippocampal neurons.

Concern on an emerging persistent contaminant, perfluorooctane sulfonate (PFOS), is increasingly growing. Although the fate, transport, distribution and bioaccumulation of PFOS have been documented, its toxicological effects especially neurotoxicity remain largely unknown. In this study, the effects of PFOS on ion channels including potassium and sodium channels and exogenous glutamate-activated current in cultured rat hippocampal neurons were examined, based on whole-cell patch-clamp recording. PFOS markedly increased two subtypes of potassium currents, including transient outward current and delayed rectifier current, at doses over 10µM. PFOS did not affect the amplitude of sodium current at all administrated doses (1, 10 or 100µM) but clearly shifted the activation current-voltage curve toward negatively potential. Further, PFOS significantly altered the glutamate-activated current at all doses. Taken together these findings indicated that PFOS disturbs the neuronal physiological processes, which revealed the damage of this pollutant to nerve system and will be helpful for further exploration to its underlying mechanism.

Activity-dependent development of callosal projections in the somatosensory cortex.

The corpus callosum is the largest commissural system in the mammalian brain, but the mechanisms underlying its development are not well understood. Here we report that neuronal activity is necessary for the normal development and maintenance of callosal projections in the mouse somatosensory cortex. We labeled a subpopulation of layer II/III callosal neurons via in utero electroporation and traced their axons in the contralateral cortex at different postnatal stages. Callosal axons displayed region- and layer-specific projection patterns within the first 2 weeks postnatally. Prenatal suppression of neuronal excitation was achieved via electroporation-induced overexpression of the inward rectifying potassium channel Kir2.1 in layer II/III cortical neurons. This resulted in abnormal callosal projections with many axons extending beyond layers II-III to terminate in layer I. Others failed to terminate at the border between the primary and secondary somatosensory cortices. Blocking synaptic transmission via expression of the tetanus toxin light chain (TeNT-LC) in these axons produced a more pronounced reduction in the projections to the border region, and the eventual disappearance of callosal projections over the entire somatosensory cortex. When Kir2.1 and TeNT-LC were coexpressed, callosal axon targeting exhibited a more severe phenotype that appeared to represent the addition of the effects produced by individual expression of Kir2.1 and TeNT-LC. These results underscore the importance of activity in regulating the developing neural connections and suggest that neuronal and synaptic activities are involved in regulating different aspects of the development of callosal projection.

[Experimental studies on treatment of HSV infections with photodynamic therapy using 5-aminolevulinic acid].

OBJECTIVE: To investigate in vitro and in vivo anti-human herpes simplex virus effects of photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA). METHODS: Guinea pigs model of cutaneous herpes virus infection was applied, and Vero cells infected by HSV-I and HSV-II were used as experimental systems to observe the antiherpes effect of ALA-PDT. RESULTS: The in vitro experiments showed that ALA-PDT has antiherpes effect on HSV-I and HSV-II, its effect was similar to that of acyclovir. The results of animal experiments showed that ALA-PDT had significant therapeutic effect on guinea pigs model of cutaneous herpes virus infection, the effect was dose-related. CONCLUSION: ALA-PDT could be effective in treating HSV infections, which may provide a new approach to the treatment of viral infections.

[Analysis of human H5N1 virus hemagglutinin gene isolated from the mainland of China].

BACKGROUND: To analyze the genetic and antigenic characteristics of human H5N1 virus isolated from the mainland of China. METHODS: The hemagglutinin (HA) gene of human H5N1 virus were sequenced and analyzed. RESULTS: The results of HA gene sequencing showed that all the virus isolates belong to the same group because of the high similarity, but they were different from the virus isolated from Thailand and Vietnam. The sequence data also showed that the receptor specificity and the connecting peptide between HA1 and HA2 are still avian influenza origin. CONCLUSION: The virus isolates from mainland of China until now belong to the same group and are different from the virus isolated from Thailand and Vietnam, and there is no evidence showing the human-avian influenza reassortant and recombination.

[Clinical characteristic analysis of the first human case infected by influenza A (H5N1) in Jiangxi Province].

OBJECTIVE: To describe the clinical, laboratory and radiological presentation of a human case infected by influenza A (H5N1), and to understand its management and prognosis. METHODS: The clinical and autopsy data of the first human case infected by influenza A (H5N1) in Jiangxi Province were collected and analyzed. RESULTS: The first case infected by influenza A (H5N1) in Jiangxi Province was confirmed by laboratory findings with reverse transcription-polymerase chain reaction (RT-PCR) and influenza A (H5N1) isolation. The patient had been healthy in the past and exposed to the environment of bird flu before illness. The initial symptoms included high fever with influenza-like symptoms, and then cough and purulent sputum mixed with blood appeared. The clinical situation deteriorated progressively with occurrence of diarrhea and dyspnea. Laboratory abnormalities included decrease of peripheral white blood cells and lymphocytes, urine protein, dramatic increase of enzymes associated with hepatic injury and myocarditis and decrease of serum albumin. Six days later, penicillin-resistant streptococcus pneumoniae was isolated from multiple sputum cultures. With the deterioration of clinical situation, several other bacteria and fungi were found in sputum culture. Pulmonary infiltrates were evident in right middle and lower lobe at day 5 after illness, and rapidly progressed to involve bilateral lungs as acute respiratory distress syndrome (ARDS)-like changes. The patient was treated with antiviral, antibacterial, and antifungal reagents, and corticosteroids and invasive mechanical ventilation were also administered, but without any improvement. The patient died 27 days after the onset of symptoms and an autopsy was performed. Pathologically, the lungs exhibited diffuse alveolar damage. The lymphocytes in the spleen, the lymph nodes and the tonsils were depleted prominently with histiocytic hyperplasia and hemophagocytic phenomena. Edema and degeneration of myocytes in the heart and extensive acute tubular necrosis in the kidney were observed. CONCLUSION: The prognosis was very poor if influenza A (H5N1) infected human cases was developed as ARDS with multiple organ damage or failure.

Efficient and quick inactivation of SARS coronavirus and other microbes exposed to the surfaces of some metal catalysts.

OBJECTIVE: To study the two metal catalysts Ag/Al2O3 and Cu/Al2O3 that interdict the transmission pathway for SARS and other respiratory infectious diseases. METHODS: Two metal catalysts Ag/Al2O3 and Cu/Al2O3 were pressed into wafers. One hundred microL 10(6) TCID50/mL SARS-CoV, 100 microL 10(6) PFU/mL recombinant baculovirus expressing hamster's prion protein (haPrP) protein and roughly 10(6) E. coli were slowly dropped onto the surfaces of the catalyst wafers and exposed for 5 and 20 min, respectively. After eluted from the surfaces of wafers, the infectivity of viruses and propagation of bacteria were measured. The expression of PrP protein was determined by Western blot. The morphological changes of bacteria were observed by electronic microscopy. RESULTS: After exposure to the catalysts surfaces for 5 and 20 min, the infectivity of SARS-CoV in Vero cells and baculovirus in Sf9 cells dropped down to a very low and undetectable level, and no colony was detected using bacteria culture method. The expression of haPrP protein reduced to 21.8% in the preparation of Sf9 cells infected with recombinant baculovirus exposed for 5 min and was undetectable exposed for 20 min. Bacterial membranes seemed to be cracked and the cytoplasm seemed to be effluent from cell bodies. CONCLUSION: Exposures to the surfaces of Ag/Al2O3 and Cu/Al2O3 destroy the replication and propagation abilities of SARS-CoV, baculovirus and E. coli. Inactivation ability of metal catalysts needs to interact with air, utilizing oxygen molecules in air. Efficiently killing viruses and bacteria on the surfaces of the two metal catalysts has a promising potential for air-disinfection in hospitals, communities, and households.

SARS patients-derived human recombinant antibodies to S and M proteins efficiently neutralize SARS-coronavirus infectivity.

OBJECTIVE: To develop a specific SARS virus-targeted antibody preparation for emergent prophylaxis and treatment of SARS virus infection. METHODS: By using phage display technology, we constructed a naive antibody library from convalescent SARS patient lymphocytes. To obtain the neutralizing antibody to SARS virus surface proteins, the library panning procedure was performed on purified SARS virions and the specific Fab antibody clones were enriched by four rounds of repeated panning procedure and screened by highthroughput selection. The selected Fab antibodies expressed in the periplasma of E. coli were soluble and further purified and tested for their binding properties and antiviral function to SARS virus. The functional Fab antibodies were converted to full human IgG antibodies with recombinant baculovirus/insect cell systems and their neutralizing activities were further determined. RESULTS: After four rounds of the panning, a number of SARS-CoV virus-targeted human recombinant Fab antibodies were isolated from the SARS patient antibody library. Most of these were identified to recognize both natural and recombinant SARS spike (S) proteins, two Fab antibodies were specific for the virus membrane (M) protein, only one bound to SARS-CoV nucleocapsid protein. The SARS-CoV S and M protein-targeted Fab or IgG antibodies showed significant neutralizing activities in cytopathic effect (CPE) inhibition neutralization test, these antibodies were able to completely neutralize the SARS virus and protect the Vero cells from CPE after virus infection. However, the N protein-targeted Fab or IgG antibodies failed to neutralize the virus. In addition, the SARS N protein-targeted human Fab antibody reacted with the denatured N proteins, whereas none of the S and M protein specific neutralizing antibodies did. These results suggested that the S and M protein-specific neutralizing antibodies could recognize conformational epitopes which might be involved in the binding of virions to cellular receptors and the fusion activity of the virus. CONCLUSION: The SARS-CoV spike protein and membrane proteins are able to elicite efficient neutralizing antibodies in SARS patients. The neutralizing antibodies we generated in this study may be more promising candidates for prophylaxis and treatment of SARS infection.