Clozapine generates obsessive compulsive disorder-like behavior in mice.

Clozapine is thought to induce obsessive compulsive symptoms (OCS) in schizophrenic patients. However, because OCS are often comorbid with schizophrenia regardless of clozapine treatment, it remains unclear whether clozapine can generate OCS de novo. Thus, it has been difficult to establish a causal link between clozapine and OCS in human studies. To address this question, we asked whether chronic treatment with clozapine can induce obsessive compulsive disorder (OCD)-like behavior in mice. We injected mice with long-term continuous release pellets embedded with clozapine four times at 60-day intervals and then monitored the mice for signs of OCD-like behavior up to 40 wk. of age. We found clozapine increases grooming behavior as early as 30 wk. of age. We also investigated the effect clozapine on grooming behavior in Sapap3 knockout (KO) mice, which are a well-known animal model of OCD. In Sapap3 heterozygous KO mice, clozapine increases grooming behavior much earlier than in wild-type mice, suggesting a clozapine-OCD gene interaction. Fluoxetine, which is often used in the treatment of OCS and OCD, reduced the grooming behavior induced by clozapine. These data demonstrate that chronic clozapine treatment can generate OCD-like behavior in mice and support the hypothesis that clozapine produces de novo OCS regardless of schizophrenia status.

Autism-like behaviors in male mice with a Pcdh19 deletion.

Mutations in protocadherin 19 (PCDH19), which is on the X-chromosome, cause the brain disease Epilepsy in Females with Mental Retardation (EFMR). EFMR is also often associated with autism-like symptoms. In mice and humans, epilepsy occurs only in heterozygous females who have a mixture of PCDH19 wild-type (WT) and mutant cells caused by random X-inactivation; it does not occur in hemizygous PCDH19 mutant males. This unique inheritance pattern strongly suggests the underlying disease mechanism operates via interference between WT and mutant cells rather than being a result of complete loss of PCDH19 functions. Although it remains unclear whether the other symptoms of EFMR also conform to this unique genotype-phenotype relationship, PCDH19 mutant males were recently reported to demonstrate autism-like symptoms. We, therefore, used a Pcdh19 knockout (KO) mouse model to ask whether a complete lack of PCDH19 causes autism-like behaviors. Consistent with the autism observed in EFMR females, we found Pcdh19 heterozygous KO female mice (with mosaic expression of PCDH19) show defects in sociability in the 3-chamber test. Surprisingly, hemizygous Pcdh19 KO male mice (without any PCDH19 expression) exhibit impaired sociability in the 3-chamber test and reduced social interactions in the reciprocal social interaction test. We also observed that, compared to WT mice, mutant mice display more repetitive behaviors, including self-grooming and rearing. These findings indicate that hemizygous Pcdh19 KO male mice show autism-like phenotypes.

Assessment of mGluR5 KO mice under conditions of low stress using a rodent touchscreen apparatus reveals impaired behavioural flexibility driven by perseverative responses.

Genetic and pharmacological manipulations targeting metabotropic glutamate receptor 5 (mGluR5) affect performance in behavioural paradigms that depend on cognitive flexibility. Many of these studies involved exposing mice to highly stressful conditions including electric foot shocks or water immersion and forced swimming. Because mGluR5 is also implicated in resilience and stress responses, however, apparent impairments in inhibitory learning may have been an artifact of manipulation-induced changes in affective state. To address this, we present here a characterization of cognitive flexibility in mGluR5 knockout (KO) mice conducted with a rodent touchscreen cognitive assessment apparatus in which the animals experience significantly less stress.Our results indicate a significant reversal learning impairment relative to wild-type (WT) controls in the two-choice Visual Discrimination-Reversal (VDR) paradigm. Upon further analysis, we found that this deficit is primarily driven by a prolonged period of perseveration in the early phase of reversal. We also observed a similar perseveration phenotype in the KO mice in the Extinction (EXT) paradigm. In addition, mGluR5 KO mice show higher breakpoints in the touchscreen Progressive Ratio (PR) and altered decision making in the Effort-related Choice (ERC) tasks. Interestingly, this impairment in PR is an additional manifestation of an increased propensity to perseverate on the emission of relatively simplistic behavioural outputs.Together, these findings suggest that under conditions of low stress, mGluR5 KO mice exhibit a pronounced perseverative phenotype that blunts cognitive flexibility.

Photothermal-modulated drug delivery and magnetic relaxation based on collagen/poly(γ-glutamic acid) hydrogel.

Injectable and stimuli-responsive hydrogels have attracted attention in molecular imaging and drug delivery because encapsulated diagnostic or therapeutic components in the hydrogel can be used to image or change the microenvironment of the injection site by controlling various stimuli such as enzymes, temperature, pH, and photonic energy. In this study, we developed a novel injectable and photoresponsive composite hydrogel composed of anticancer drugs, imaging contrast agents, bio-derived collagen, and multifaceted anionic polypeptide, poly (γ-glutamic acid) (γ-PGA). By the introduction of γ-PGA, the intrinsic temperature-dependent phase transition behavior of collagen was modified to a low viscous sol state at room temperature and nonflowing gel state around body temperature. The modified temperature-dependent phase transition behavior of collagen/γ-PGA hydrogels was also evaluated after loading of near-infrared (NIR) fluorophore, indocyanine green (ICG), which could transform absorbed NIR photonic energy into thermal energy. By taking advantage of the abundant carboxylate groups in γ-PGA, cationic-charged doxorubicin (Dox) and hydrophobic MnFe2O4 magnetic nanoparticles were also incorporated successfully into the collagen/γ-PGA hydrogels. By illumination of NIR light on the collagen/γ-PGA/Dox/ICG/MnFe2O4 hydrogels, the release kinetics of Dox and magnetic relaxation of MnFe2O4 nanoparticles could be modulated. The experimental results suggest that the novel injectable and NIR-responsive collagen/γ-PGA hydrogels developed in this study can be used as a theranostic platform after loading of various molecular imaging probes and therapeutic components.

Hyaluronic acid-supported combination of water insoluble immunostimulatory compounds for anti-cancer immunotherapy.

A novel powder-form combination adjuvant system containing two immunostimulatory compounds was firstly developed and evaluated as a therapeutic intervention for cancer immunotherapy. With the help of hyaluronic acid (HA), water insoluble monophosphoryl lipid A (MPL), QS21 and imiquimod (R837), could be easily dispersed in aqueous solution and lyophilized as powder-form, which have an advantage in room-temperature storage stability compared with those conventional liquid formulation that requires cold storage. Two kinds of HA-based combination vaccine adjuvants (HA/MPL/QS21, HMQ and HA/MPL/R837, HMR) contributed to the increase of both humoral and cellular immunity, which is very important for efficient cancer immunotherapy. Through the challenge experiments in EG7-OVA (mouse lymphoma-expressing OVA) tumor-bearing mice model, we found out that the immunostimulatory effects of HMQ and HMR were successful in the inhibition of tumor proliferation. Taken together, both HA-based powder-form combination adjuvant systems are expected to be used as potent prophylactic and therapeutic cancer vaccine.

Injectable and Pathogen-Mimicking Hydrogels for Enhanced Protective Immunity against Emerging and Highly Pathogenic Influenza Virus.

Seasonal emerging infectious diseases such as influenza A impose substantial risk and need new translational strategies to achieve active immunomodulation. Here, a novel injectable pathogen-mimicking hydrogel (iPMH) that can enhance both cellular and humoral immune responses is suggested. By the help of poly(γ-glutamic acid) that has abundant carboxylate groups and dispersion helper function, hydrophobic immunostimulatory 3-O-desacyl-4'-monophosphoryl lipid A (MPLA) molecules and viral antigens (PR8, W150) can be successfully combined as pathogen-mimicking adjuvants. Polyelectrolyte complex between the poly(γ-glutamic acid)-based adjuvants and collagens generate in situ gel-forming hydrogel at physiological temperature. When the iPMH are immunized, they act as a pathogen-mimicking (MPLA, H1N1, H5N1) immune priming center and a depot for continuous stimulation of immune system, resulting in the induction of high levels (8.5 times higher) of antigen-specific IgG titers in the sera of mice and the increased number of IFN-γ-producing cells (7.3 times higher) compared with those in the groups immunized with antigen plus clinically used aluminum gels. Following the intranasal infection of the mouse adapted virus (emerging infectious 2009 H1N1 and highly pathogenic 2006 H5N1) at 50 times the 50% lethal dose, the mice immunized with viral antigens plus iPMH exhibit 100% protective immunity against lethal virus challenge.

Programming of Influenza Vaccine Broadness and Persistence by Mucoadhesive Polymer-Based Adjuvant Systems.

The development of an anti-influenza vaccine with the potential for cross-protection against seasonal drift variants as well as occasionally emerging reassortant viruses is essential. In this study, we successfully generated a novel anti-influenza vaccine system combining conserved matrix protein 2 (sM2) and stalk domain of hemagglutinin (HA2) fusion protein (sM2HA2) and poly-γ-glutamic acid (γ-PGA)-based vaccine adjuvant systems that can act as a mucoadhesive delivery vehicle of sM2HA2 as well as a robust strategy for the incorporation of hydrophobic immunostimulatory 3-O-desacyl-4'-monophosphoryl lipid A (MPL) and QS21. Intranasal coadministration of sM2HA2 and the combination adjuvant γ-PGA/MPL/QS21 (CA-PMQ) was able to induce a high degree of protective mucosal, systemic, and cell-mediated immune responses. The sM2HA2/CA-PMQ immunization was able to prevent disease symptoms, confering complete protection against lethal infection with divergent influenza subtypes (H5N1, H1N1, H5N2, H7N3, and H9N2) that lasted for at least 6 mo. Therefore, our data suggest that mucosal administration of sM2HA2 in combination with CA-PMQ could be a potent strategy for a broad cross-protective influenza vaccine, and CA-PMQ as a mucosal adjuvant could be used for effective mucosal vaccines.