Compensatory enhancement of paternal care in maternally neglected mice family.

Parental care strategies, ranging from biparental to uniparental, evolve based on factors affecting sexual conflict over care. Plasticity in how parents respond to reduction in each other's care effort is thus proposed to be important in the evolution of parental care behaviors. Models predict that 'obligate' biparental care is stable when a parent responds to reduced partner effort with 'partial' compensation, trading-off current and future reproduction. A meta-analysis of experimental studies on biparental birds also revealed partial compensation, supporting coevolution of parental care type and plasticity pattern. However, few studies have addressed this issue across different taxa and different parental care types. In laboratory mice, a female-biased 'facultative' biparental species, fathers paired with a competent mother rarely provide care. We show that, when mated with a pup-neglecting mutant mother, fathers increased care effort to 'fully' compensate for the lost maternal care in both pup survival rate and total care amount. Pup retrieval latency was significantly shorter, and neural activity in relevant brain regions twice as high, suggesting enhanced motivation. This study with mice not only opens a road to explore the neural correlates of paternal plasticity but will also help understand how behavioral plasticity contributes to adaptive evolution of parental care behaviors.

Abnormal maternal behavior in mice lacking phospholipase Cß1.

Motherhood goes through preparation, onset and maintenance phases until the natural weaning. A variety of changes in hormonal/neurohormonal systems and brain circuits are involved in the maternal behavior. Hormones, neuropeptides, and neurotransmitters involved in maternal behavior act via G-protein-coupled receptors, many of which in turn activate plasma membrane enzymes including phospholipase C (PLC) ß isoforms. In this study, we examined the effect of PLCß1 knockout (KO) on maternal behavior. There was little difference between PLCß1-KO and wild-type (WT) dams in the relative time spent in maternal behavior during the period between 24 h prepartum and 12 h postpartum (-24 h ∼ PPH 12). After PPH 18, however, PLCß1-KO dams neglected their pups so that they all died in 2-3 days. In the pup retrieval test, latency was not different during the period within PPH 12, but after PPH 18, PLCß1-KO dams could not finish pup retrieval in a given time. During both periods, FosB expression in the nucleus accumbens (NAcc) of PLCß1-KO dams was significantly lower than WT, but not different in the medial preoptic area (mPOA). Given that mPOA activity is required for initiation of maternal behavior, and that NAcc is known to be involved in maternal motivation and maintenance of maternal behavior, our results suggest that PLCß1 signaling is essential for transition from the onset to maintenance phase of maternal behavior.

Training-Dependent Change in Content of Association in Appetitive Pavlovian Conditioning.

In appetitive Pavlovian conditioning, experience with a conditional relationship between a cue [conditioned stimulus (CS)] and a reward [unconditioned stimulus (US)] bestows CS with the ability to promote adaptive behavior patterns. Different features of US (e.g., identity-specific sensory, general motivational) can be encoded by CS based on the nature of the CS-US relationship experienced (e.g., temporal factors such as training amount) and the content of association may determine the influence of CS over behavior (e.g., mediated learning, conditioned reinforcement). The content of association changed with varying conditioning factors, thereby altering behavioral consequences, however, has never been addressed in relevant brain signals evoked by CS. Our previous study found that phospholipase C ß1-knockout (PLCß1-KO) mice display persistent mediated learning over the extended course of odor-sugar conditioning, and that wild-type (WT) mice lose mediated learning sensitivity after extended training. In this study, in order to see whether this behavioral difference between these two genotypes comes from a difference in the course of association content, we examined whether odor CS can evoke the taste sensory representation of an absent sugar US after minimal- and extended training in these mice. In contrast to WT, which lost CS-evoked neural activation (c-Fos expression) in the gustatory cortex after extended training, KO mice displayed persistent association with the sensory feature of sugar, suggesting that sensory encoding is reliably linked to mediated learning sensitivity and there is a training-dependent change in the content of association in WT. PLCß1 knockdown in the left medial prefrontal cortex (mPFC) resulted in mediated learning sensitivity and CS-evoked gustatory cortical activation after extended training, proposing a molecular component of the neural system underlying this Pavlovian conditioning process. We also discuss how disruption of this process is implicated for hallucination-like behaviors (impaired reality testing).

Impaired Reality Testing in Mice Lacking Phospholipase Cß1: Observed by Persistent Representation-Mediated Taste Aversion.

Hallucinations and delusions are the most prominent symptoms of schizophrenia and characterized by impaired reality testing. Representation-mediated taste aversion (RMTA) has been proposed as a potential behavioral assessment of reality testing and has been applied to a neurodevelopmental rat model of schizophrenia. However, the theory underlying this approach has not been generalized yet with any demonstration of impaired reality testing in other animal models of schizophrenia, such as genetically-modified mice. We devised a RMTA procedure for mice that combines a Pavlovian association protocol pairing odor conditioned stimulus (CS) with sugar reward unconditioned stimulus (US), and a conditioned taste aversion (CTA) method. In this RMTA paradigm, we compared performances of wild-type (PLCß1+/+) mice and phospholipase C ß1 knock-out (PLCß1-/-) mice which are known as one of the genetic models for schizophrenia. With a minimal amount of initial odor-sugar associative training, both PLCß1+/+ and PLCß1-/- mice were able to form an aversion to the sugar reward when the odor CS predicting sugar was paired with nausea. With an extended initial training, however, only PLCß1-/- mice could form a RMTA. This persistent RMTA displayed by PLCß1-/- mice shows their inability to distinguish real sugar from the CS-evoked representation of sugar at a stage in associative learning where wild-type mice normally could differentiate the two. These results demonstrate an impaired reality testing first observed in a genetic mouse model of schizophrenia, and suggest that RMTA paradigm may, with general applicability, allow diverse biological approaches to impaired reality testing.

Expression of human ß-defensin-2 in the prostate.

OBJECTIVE: To investigate the expression and regulation of human ß-defensin-2 (HBD-2) in the prostate. PATIENTS AND METHODS: Normal human prostate epithelial cell line (RWPE-1), human prostate cancer cell lines (DU-145, PC-3), and paraffin-embedded prostate tissue from patients with benign prostatic hyperplasia (BPH) were analysed by RT-PCR and immunohistochemical staining. HBD-2 expression was also analysed by RT-PCR and ELISA in RWPE-1 cells treated with lipopolysaccharide (LPS). Nuclear factor-κB (NF-κB) activation was assessed by IκBα immunoblotting and electrophoretic mobility shift assay (EMSA). RESULTS: BPH tissue and all of the tested prostate cell lines other than PC-3 constitutively express HBD-2 mRNA. HBD-2 protein was strongly detected in prostate gland tissue surrounded by inflammatory cells including macrophages. Exposure to LPS induced HBD-2 upregulation and NF-κB activation, as assessed by IκBα phosphorylation and degradation in RWPE-1 cells. Bay11-7082, an NF-κB inhibitor prevented LPS-induced HBD-2 production in RWPE-1 cells. CONCLUSIONS: Prostate epithelial cells may constitutively express HBD-2, and its expression was upregulated by LPS. Our data indicate that HBD-2 may be an important immunomodulatory factor in prostate function. Expression of HBD-2 in normal prostates and the potential role of HBD-2 in prostatitis and BPH should be addressed in the future.

17-Allylamino-17-demethoxygeldanamycin down-regulates hyaluronic acid-induced glioma invasion by blocking matrix metalloproteinase-9 secretion.

Hyaluronic acid (HA) has been implicated in cell adhesion, motility, and tumor progression in gliomas. We previously reported that HA stimulates secretion of matrix metalloproteinase-9 (MMP-9) and induces glioma invasion. However, the molecular mechanism of HA action and therapeutic strategies for blocking HA-induced MMP-9 secretion remain unknown. Here, we report that the Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) blocks MMP-9 secretion and that HA-induced nuclear factor-kappaB (NF-kappaB) activation is mediated by IkappaB kinase, which phosphorylates the NF-kappaB inhibitor IkappaBalpha and promotes its degradation. In addition, using an RNA interference approach, we show that the focal adhesion kinase plays a critical role in mediating HA-induced NF-kappaB activation, which resulted in increased MMP-9 expression and secretion, cell migration, and invasion. Importantly, we show that 17-AAG acts by blocking focal adhesion kinase activation, thereby inhibiting IkappaB kinase-dependent IkappaBalpha phosphorylation/degradation, NF-kappaB activation, and MMP-9 expression. This leads to suppression of HA-induced cell migration and invasion. Based on our data, we propose that 17-AAG is a candidate drug for treatment of highly invasive gliomas resulting from HA-induced, NF-kappaB-mediated MMP-9 secretion.