Characterization of social behaviors in caspase-3 deficient mice

Postnatal Allergic Inhalation Induces Glial Inflammation in the Olfactory Bulb and Leads to Autism-Like Traits in Mice

Autism spectrum disorder (ASD) is one of the most prevalent neurodevelopmental disorders. To explore its pathophysiology, we investigated the association between neonatal allergic exposure and behavioral changes. Adult female C57BL/6J mice were immunized with adjuvant (aluminum hydroxide) or ovalbumin emulsified with adjuvant. After immunization, the mice were mated, and offspring were born at full term. The postnatal dams and infants were then simultaneously exposed to an allergen (ovalbumin) or vehicle via inhalation. After weaning, behavioral testing and histopathological analyses were conducted on male offspring. Compared with the vehicle-exposed offspring, the ovalbumin-exposed offspring had decreased sociability and increased repetitive behavior, thus representing an ASD-like phenotype in mice. Moreover, histopathological analyses revealed that the ovalbumin-exposed mice had increased astroglial, microglial, and eosinophilic infiltration in the olfactory bulb, as well as increased eosinophils in the nasal mucosa. The ovalbumin-exposed mice also had decreased dendritic spine density and a lower proportion of mature spines, suggesting the impairment of stimulus-induced synaptogenesis. In conclusion, postnatal allergic exposure induced an ASD-like phenotype, as well as allergic rhinitis, which was followed by glial inflammation in the olfactory bulb parenchyma.

Exploring caspase functions in mouse models

Caspases are enzymes with protease activity. Despite being known for more than three decades, caspase investigation still yields surprising and fascinating information. Initially associated with cell death and inflammation, their functions have gradually been revealed to extend beyond, targeting pathways such as cell proliferation, migration, and differentiation. These processes are also associated with disease mechanisms, positioning caspases as potential targets for numerous pathologies including inflammatory, neurological, metabolic, or oncological conditions. While in vitro studies play a crucial role in elucidating molecular pathways, they lack the context of the body's complexity. Therefore, laboratory animals are an indispensable part of successfully understanding and applying caspase networks. This paper aims to summarize and discuss recent knowledge, understanding, and challenges in caspase knock-out mice.

NARP-related alterations in the excitatory and inhibitory circuitry of socially isolated mice: developmental insights and implications for autism spectrum disorder

Background

Social isolation during critical periods of development is associated with alterations in behavior and neuronal circuitry. This study aimed to investigate the immediate and developmental effects of social isolation on firing properties, neuronal activity-regulated pentraxin (NARP) and parvalbumin (PV) expression in the prefrontal cortex (PFC), social behavior in juvenile socially isolated mice, and the biological relevance of NARP expression in autism spectrum disorder (ASD).

Methods

Mice were subjected to social isolation during postnatal days 21-35 (P21-P35) and were compared with group-housed control mice. Firing properties in the PFC pyramidal neurons were altered in P35 socially isolated mice, which might be associated with alterations in NARP and PV expression.

Results

In adulthood, mice that underwent juvenile social isolation exhibited difficulty distinguishing between novel and familiar mice during a social memory task, while maintaining similar levels of social interaction as the control mice. Furthermore, a marked decrease in NARP expression in lymphoblastoid cell lines derived from adolescent humans with ASD as compared to typically developing (TD) humans was found.

Conclusion

Our study highlights the role of electrophysiological properties, as well as NARP and PV expression in the PFC in mediating the developmental consequences of social isolation on behavior.

Cholestatic liver disease leads to significant adaptative changes in neural circuits regulating social behavior in mice to enhance sociability

BACKGROUND & AIMS

Cholestatic liver diseases (CLD) are commonly associated with behavioral changes, including social isolation, that negatively affects patient quality of life and remains unaltered by current therapies. It remains unclear whether CLD-associated social dysfunction stems from a direct effect on the brain, or from the psychological impact of CLD. The psychological component of disease is absent in animals, so we investigated the impact of CLD on social behavior and gene expression profiles in key social behavior-regulating brain regions in a mouse model.

METHODS

CLD due to bile duct ligation was used with the three-chamber sociability test for behavioral phenotyping. Differentially expressed gene (DEG) signatures were delineated in 3 key brain regions regulating social behavior using RNA-seq. Ingenuity Pathway Analysis (IPA®) was applied to streamline DEG data interpretation and integrate findings with social behavior-regulating pathways to identify important brain molecular networks and regulatory mechanisms disrupted in CLD.

RESULTS

CLD mice exhibited enhanced social interactive behavior and significantly altered gene expression in each of the three social behavior-regulating brain regions examined. DEG signatures in BDL mice were associated with key IPA®-identified social behavior-regulating pathways including Oxytocin in Brain Signaling, GABA Receptor Signaling, Dopamine Receptor Signaling, and Glutamate Receptor Signaling.

CONCLUSIONS

CLD causes complex alterations in gene expression profiles in key social behavior-regulating brain areas/pathways linked to enhanced social interactive behavior. These findings, if paralleled in CLD patients, suggest that CLD-associated reductions in social interactions predominantly relate to psychological impacts of disease and may inform new approaches to improve management.

Sex-specific neurobehavioral and biochemical effects of developmental exposure to Malathion in offspring mice

Malathion is an organophosphate pesticide (OP) commonly used in agriculture, industry, and veterinary medicine. Sex is a crucial factor in responding to neurotoxicants, yet the sex-specific effects of OP exposure, particularly neurological impairments following chronic low-level exposure remains limited. Our study aims to evaluate the neurobehavioral and biochemical effects of developmental exposure to Malathion across sexes. Pregnant mice were exposed to a low oral dose of Malathion from gestation up to the weaning of the pups, which were individually gavaged with a similar dose regimen until postnatal day 70. Our results show that Malathion decreased body weight and food intake, reduced locomotor activity and recognition memory. Motor coordination and special memory were only altered in females, whereas we found a male-specific effect of Malathion on social behavior and marble burying. These alterations were accompanied by increased malondialdehyde (MDA), decreased brain acetylcholinesterase activity (AChE), and disrupted brain redox homeostasis. Our findings about the effects of Malathion exposure across sexes may, in part, contribute to understanding the dimorphic susceptibilities observed in neurological disorders.

Maternal exposure of mice to glyphosate induces depression- and anxiety-like behavior in the offspring via alterations of the gut-brain axis

The past decade has been characterized by increased awareness and de-stigmatization of mental health issues, in particular the most common neuropsychiatric disorders depression and anxiety. Further, with growing understanding of neurodevelopmental disorders such as attention deficit and hyperactivity disorder and autism spectrum disorder, the number of diagnosed patients has increased. The pathogenesis of these behavioral disorders is multifactorial and early-life exposure to environmental chemicals has been proposed to be a relevant risk factor that might mediate these effects by disturbances on the gut-brain-axis. However, for glyphosate, the most widely used pesticide worldwide, there are only limited and inconsistent findings that link chronic low-dose exposure in particular during early life to neurobehavioral disorders. Here, we explored the impact of maternal oral glyphosate exposure (0.5 and 50 mg/kg body weight/day) during pregnancy and the lactational period on offspring's behavior, brain gene expression and gut microbiota using a cross-generational mouse model. Behavioral analyses revealed a depression- and anxiety-like behavior as well as social deficits most notably in adult female offspring of glyphosate-exposed dams. Furthermore, the expression of tryptophan hydroxylase 2, an enzyme discussed to be linked to behavioral problems, was reduced in the hippocampus of female offspring and correlated to a glyphosate-induced DNA hypermethylation of the gene. Moreover, maternal glyphosate exposure significantly altered the gut microbiota in the female offspring including a decreased abundance of Akkermansia and increased abundance of Alistipes and Blautia, bacteria involved in tryptophan metabolism and associated with depression- and anxiety-like disorders. Our results suggest that glyphosate might influence the gut-brain axis crosstalk following in-utero and lactational exposure. This study underlines the importance of understanding the impact of exposure to pesticides on the gut-brain axis and further emphasizes the need for microbiome analyses to be compulsorily included in health risk assessments of pesticides.

Revisiting sociability: Factors facilitating approach and avoidance during the three-chamber test

The three-chamber test, the so-called sociability test, has been widely used to assess social deficits based on impaired socially oriented investigations in rodent models. An innate motivation for investigating conspecifics is theoretically a prerequisite for gaining sociability scores in this paradigm. However, several relevant factors mediating investigatory motives, such as familiarity, attractiveness, and aggression, may affect sociability scores, which must be verified to obtain an adequate evaluation of the psychiatric phenotypes exhibited by disease-relevant rodent models. We assessed the social and non-social factors that mediate proximity preference by the three-chamber test with standard C57BL/6 J (B6) mice and low sociability BTBR+ltpr3tf/J (BTBR) mice. Strains of the opponents had no effect. Sexual cues (i.e., opposite sex) increased proximity preference in both strains of mice; in contrast, novel objects induced an approach in B6 mice but avoidance in BTBR mice. Single-housing before testing, stimulated social motive, affected BTBR mice but not B6 mice. BTBR females showed increased proximity preference across the sessions, and BTBR males showed increased preference toward a male B6 stimulus, but not a male BTBR stimulus. The male preference was restored when the male BTBR stimulus was anesthetized. In addition, self-grooming was facilitated by social and non-social novelty cues in both strains. B6 mice predominantly exhibited an investigatory approach toward social or non-social stimuli, whereas BTBR mice recognized social cues but tended to show avoidance. The three-chamber test could evaluate approach-avoidance strategies in target mouse strains that comprise innate social distance between mice.

Beneficial role of rosemary extract on oxidative stress-mediated neuronal apoptosis in rotenone-induced attention deficit hyperactivity disease in juvenile rat model

BACKGROUND AND AIM

Attention deficit hyperactivity disorder (ADHD) is heterogeneous neurobehavioral disorders that co-exist with cognitive and learning deficits affecting 3-7% of children. We study the role of rosemary in the protection of the prefrontal cortical neurons against rotenone-induced ADHD in juvenile rats.

METHODS

Twenty-four juvenile rats were divided into four groups (n=6): control group, received olive oil 0.5 ml/kg/day/ I.P. for 4 weeks, rosemary group received rosemary 75 mg/kg/day/ I.P. for 4 weeks, rotenone group received rotenone 1 mg/kg/day/ I.P. dissolved in olive oil for 4 days and combined group received rotenone 1 mg/kg/day/ I.P. for 4 days and rosemary 75 mg/kg/day/ I.P. for 4 weeks.

RESULTS

Rotenone group showed higher impulsivity with reduction in the recognition index and total locomotor activity. However, combined group showed significant improvement in the recognition index and the total locomotor activity. Neurochemical analysis disclosed that rotenone decreased levels of GSH and significantly increased lipid peroxidation and oxidative stress. The administration of rosemary amended these neurochemical changes. Rotenone caused a significant increase in serum amyloid protein A and C-reactive protein levels indicating a marked state of inflammation. Rosemary ameliorated these biochemical changes. The immunohistochemical expression of tyrosine hydroxylase was decreased in the rotenone group. On the other hand, caspase-3 was increased in the rotenone group. PCR confirmed immunohistochemical results for gene expression.

CONCLUSIONS

The findings of the behavioral, neurochemical, biochemical, immunohistochemical and molecular outcomes suggested that rosemary could fight oxidative stress, inflammation and apoptosis in the prefrontal cortex of rotenone-induced ADHD in juvenile rats.

Apoptotic cell death in disease-Current understanding of the NCCD 2023

Apoptosis is a form of regulated cell death (RCD) that involves proteases of the caspase family. Pharmacological and genetic strategies that experimentally inhibit or delay apoptosis in mammalian systems have elucidated the key contribution of this process not only to (post-)embryonic development and adult tissue homeostasis, but also to the etiology of multiple human disorders. Consistent with this notion, while defects in the molecular machinery for apoptotic cell death impair organismal development and promote oncogenesis, the unwarranted activation of apoptosis promotes cell loss and tissue damage in the context of various neurological, cardiovascular, renal, hepatic, infectious, neoplastic and inflammatory conditions. Here, the Nomenclature Committee on Cell Death (NCCD) gathered to critically summarize an abundant pre-clinical literature mechanistically linking the core apoptotic apparatus to organismal homeostasis in the context of disease.

Apoptotic proteins with non-apoptotic activity: expression and function in cancer

Apoptosis is a process of programmed cell death in which a cell commits suicide while maintaining the integrity and architecture of the tissue as a whole. Apoptosis involves activation of one of two major pathways: the extrinsic pathway, where extracellular pro-apoptotic signals, transduced through plasma membrane death receptors, activate a caspase cascade leading to apoptosis. The second, the intrinsic apoptotic pathway, where damaged DNA, oxidative stress, or chemicals, induce the release of pro-apoptotic proteins from the mitochondria, leading to the activation of caspase-dependent and independent apoptosis. However, it has recently become apparent that proteins involved in apoptosis also exhibit non-cell death-related physiological functions that are related to the cell cycle, differentiation, metabolism, inflammation or immunity. Such non-conventional activities were predominantly reported in non-cancer cells although, recently, such a dual function for pro-apoptotic proteins has also been reported in cancers where they are overexpressed. Interestingly, some apoptotic proteins translocate to the nucleus in order to perform a non-apoptotic function. In this review, we summarize the unconventional roles of the apoptotic proteins from a functional perspective, while focusing on two mitochondrial proteins: VDAC1 and SMAC/Diablo. Despite having pro-apoptotic functions, these proteins are overexpressed in cancers and this apparent paradox and the associated pathophysiological implications will be discussed. We will also present possible mechanisms underlying the switch from apoptotic to non-apoptotic activities although a deeper investigation into the process awaits further study.

Steroid hormone pathways, vitamin D and autism: a systematic review

The origins of the male preponderance in autism incidence remain unclear. The idea that perinatal factors associated with sex differentiation (e.g., steroid hormone pathways) may increase the possibility of the emergence of autism is complementary to the hypothesis that female individuals are intrinsically less likely to develop autism. Empirical evidence for the mechanistic roles of in utero steroid hormones in autism etiology is accumulating but inconsistent. We conducted a systematic review using rigorous criteria for the measurements of steroids and vitamin D exposure, to summarize the potential contributing roles of prenatal and early postnatal steroids and vitamin D alterations to the emergence of autism. We searched PubMed, PsychInfo, Scopus, and included 22 studies for qualitative synthesis. Among them, six studies examined the association of autism diagnoses in offspring and levels of steroids and precursor steroid hormones in the fetal environment, eight studies examined the associations between autism and maternal and fetal blood vitamin D levels during pregnancy and at birth, and eight studies examined the associations between offspring autism diagnoses and maternal hyperandrogenemia diagnosed before pregnancy. We identified promising and complex results regarding the relations between steroid metabolism and autism. The interpretation of findings was limited by the mostly observational study designs, insufficient investigation of the effects of offspring sex, confounders and their cumulative effects on the development of the child, and unclear impact of the timing of steroids exposure and their effects on fetal neurodevelopment.

Partial changes in apoptotic pathways in hippocampus and hypothalamus of Cc2d1a heterozygous

Alterations in the apoptosis pathway have been linked to changes in serotonin levels seen in autistic patients. Cc2d1a is a repressor of the HTR1A gene involved in the serotonin pathway. The hippocampus and hypothalamus of Cc2d1a ± mice were analyzed for the expression of apoptosis markers (caspase 3, 8 and 9). Gender differences were observed in the expression levels of the three caspases consistent with some altered activity in the open-field assay. The number of apoptotic cells was significantly increased. We concluded that apoptotic pathways are only partially affected in the pathogenesis of the Cc2d1a heterozygous mouse model. A) Apoptosis is suppressed because the cell does not receive a death signal, or the receptor cannot activate the caspase 8 pathway despite the death signal. B) Since Caspase 8 and Caspase 3 expression is downregulated in our mouse model, the mechanism of apoptosis is not activated.

Anti-inflammatory effect of Ailanthus altissima (Mill.) Swingle leaves in lipopolysaccharide-stimulated astrocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Activated astrocytes are involved in the progression of neurodegenerative diseases. Traditionally, Ailanthus altissima (Mill.) Swingle, widely distributed in East Asia, has been used as a medicine for the treatment of fever, gastric diseases, and inflammation. Although A. altissima has been reported to play an anti-inflammatory role in peripheral tissues or cells, its role in the central nervous system (CNS) remains unclear.

AIM OF THE STUDY

In the present study, we investigated the anti-inflammatory effects and mechanism of action of A. altissima in primary astrocytes stimulated by lipopolysaccharide (LPS).

MATERIALS AND METHODS

A nitrite assay was used to measure nitric oxide (NO) production, and the tetrazolium salt 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was performed to determine cytotoxicity. The expression levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and mitogen-activated protein kinase (MAPK) were determined with western blotting. Reverse-transcription PCR was used to assess the expression of inflammatory cytokines. The levels of reactive oxygen species were measured using 2,7-dichlorodihydrofluorescein diacetate. Luciferase assay and immunocytochemistry were used for assessing nuclear factor-kappa B (NF-κB) transcription and p65 localization, respectively. Memory and social interaction were analyzed using the Y-maze and three-chamber tests, respectively.

RESULTS

The ethanol extract of A. altissima leaves (AAE) inhibited iNOS and COX-2 expression in LPS-stimulated astrocytes. Moreover, AAE reduced the transcription of various proinflammatory mediators, hindered NF-κB activation, and suppressed extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) activation without p38 activation. Ultra-high performance liquid chromatography with mass spectrometry analysis revealed that AAE comprised ethyl gallate, quercetin, and kaempferol, along with luteolin, which has anti-inflammatory properties, and repressed LPS-induced nitrite levels and the nuclear translocation of p65. Finally, oral administration of AAE attenuated LPS-induced memory and social impairment in mice and repressed LPS-induced ERK and JNK activation in the cortices of mice.

CONCLUSION

AAE could have therapeutic uses in the treatment of neuroinflammatory diseases via suppression of astrocyte activation.

Targeted Suppression of Lipoprotein Receptor LSR in Astrocytes Leads to Olfactory and Memory Deficits in Mice

Perturbations of cholesterol metabolism have been linked to neurodegenerative diseases. Glia–neuron crosstalk is essential to achieve a tight regulation of brain cholesterol trafficking. Adequate cholesterol supply from glia via apolipoprotein E-containing lipoproteins ensures neuronal development and function. The lipolysis-stimulated lipoprotein receptor (LSR), plays an important role in brain cholesterol homeostasis. Aged heterozygote Lsr+/− mice show altered brain cholesterol distribution and increased susceptibility to amyloid stress. Since LSR expression is higher in astroglia as compared to neurons, we sought to determine if astroglial LSR deficiency could lead to cognitive defects similar to those of Alzheimer’s disease (AD). Cre recombinase was activated in adult Glast-CreERT/lsrfl/fl mice by tamoxifen to induce astroglial Lsr deletion. Behavioral phenotyping of young and old astroglial Lsr KO animals revealed hyperactivity during the nocturnal period, deficits in olfactory function affecting social memory and causing possible apathy, as well as visual memory and short-term working memory problems, and deficits similar to those reported in neurodegenerative diseases, such as AD. Furthermore, GFAP staining revealed astroglial activation in the olfactory bulb. Therefore, astroglial LSR is important for working, spatial, and social memory related to sensory input, and represents a novel pathway for the study of brain aging and neurodegeneration.

Different Alterations in Gut Microbiota between Bifidobacterium longum and Fecal Microbiota Transplantation Treatments in Propionic Acid Rat Model of Autism

Autism spectrum disorders (ASD) consist of a range of neurodevelopmental conditions accompanied by dysbiosis of gut microbiota. Therefore, a number of microbiota manipulation strategies were developed to restore their balance. However, a comprehensive comparison of the various methods on gut microbiota is still lacking. Here, we evaluated the effect of Bifidobacterium (BF) treatment and fecal microbiota transplantation (FT) on gut microbiota in a propionic acid (PPA) rat model of autism using 16S rRNA sequencing. Following PPA treatment, gut microbiota showed depletion of Bacteroidia and Akkermansia accompanied by a concomitant increase of Streptococcus, Lachnospiraceae, and Paraeggerthella. The dysbiosis was predicted to cause increased levels of porphyrin metabolism and impairments of acyl-CoA thioesterase and ubiquinone biosynthesis. On the contrary, BF and FT treatments resulted in a distinct increase of Clostridium, Bifidobacterium, Marvinbryantia, Butyricicoccus, and Dorea. The taxa in BF group positively correlated with vitamin B12 and flagella biosynthesis, while FT mainly enriched flagella biosynthesis. In contrast, BF and FT treatments negatively correlated with succinate biosynthesis, pyruvate metabolism, nitrogen metabolism, beta-Lactam resistance, and peptidoglycan biosynthesis. Therefore, the present study demonstrated that BF and FT treatments restored the PPA-induced dysbiosis in a treatment-specific manner.

The Efficacy of Fecal Transplantation and Bifidobacterium Supplementation in Ameliorating Propionic Acid-Induced Behavioral and Biochemical Autistic Features in Juvenile Male Rats

Gut microbiota plays a major role in neurological disorders, including autism. Modulation of the gut microbiota through fecal microbiota transplantation (FMT) or probiotic administration, such as Bifidobacteria, is suggested to alleviate autistic symptoms; however, their effects on the brain are not fully examined. We tested both approaches in a propionic acid (PPA) rodent model of autism as treatment strategies. Autism was induced in Sprague-Dawley rats by administering PPA orally (250 mg/kg) for 3 days. Animals were later treated with either saline, FMT, or Bifidobacteria for 22 days. Control animals were treated with saline throughout the study. Social behavior and selected brain biochemical markers related to stress hormones, inflammation, and oxidative stress were assessed. PPA treatment induced social impairments, which was rescued by the treatments. In the brain, Bifidobacteria treatment increased oxytocin relative to control and PPA groups. Moreover, Bifidobacteria treatment rescued the PPA-induced increase in IFN-γ levels. Both treatments increased GST levels, which was diminished by the PPA treatment. These findings indicate the potential of gut microbiota-targeted therapeutics in ameliorating behavioral deficit and underlying neural biochemistry.

Metal arsenic mediated enhancement of type-2 immunity in brains with altered locomotive activities in mice with autism-like behavioral characteristics

Exposure to metal arsenic (As) has been proposed as a risk factor for autism spectrum disorders (ASDs), which are neurodevelopmental disorders with worldwide increasing in its incidence. In the present study, BTBR T + tf/J (BTBR) mice with ASD-like behavioral characteristics and control highly social FVB mice were orally exposed to 0.1 mM arsenic(III)oxide for 4 weeks, and were compared to investigate neuroimmunological or behavioral abnormalities. IgG1:IgG2a ratios in brain tissues from BTBR mice exposed to As (BTBR-As) were significantly higher than those of BTBR-control mice (BTBR-C), but this change did not occur in FVB mice exposed to As. Levels of IL-4, IFN-γ, IL-1β, IL-17, and TNF-α in brain tissue were lowered in BTBR-As relative to BTBR-C, but this tendency was not observed with FVB mice. BTBR-As mice demonstrated decrease in relative travel distance and time spent in the center vs. the periphery of open field arena compared to BTBR-C. Sociability evaluation using three-way chamber test did not clearly demonstrate As-mediated alteration in social interaction in BTBR mice. These findings suggest the potential for As-driven predominant TH2-like reactivity profile in the brain microenvironment of BTBR mice and for As-mediated locomotive impairment probably associated with ASD.

Limited cheese intake reduces HPA axis and behavioral stress responses in male rats

Eating palatable foods reduces behavioral and hypothalamic-pituitary-adrenocortical (HPA) axis responses to stress - an idea referred to by the colloquial term "comfort" food. To study the underlying stress-relieving mechanisms of palatable foods, we previously developed a paradigm of limited sucrose feeding in which male rats are given twice-daily access to a small amount of sucrose drink and subsequently have reduced stress responses. Prior research in humans and rodents implicates high dietary sugars/carbohydrates with reduced stress responsivity. However, it is not clear whether the stress-relieving effects of the limited sucrose paradigm depend upon its macronutrient content. To test this idea, the current work measures stress responses in male rats following the limited intermittent intake of cheese - a highly palatable food that is low in sugar and other carbohydrates. The data show that a history of limited cheese intake (LCI) reduced HPA axis responses to acute psychological (restraint) and physiological (hypoxia) stressors. LCI also reduced behavioral struggling during restraint, increased sociability during a social interaction test, and increased open arm activity in the elevated plus-maze test. Z-score analyses evaluated the extent to which these behavioral effects extended within and across assays, and indicated that there was an overall reduction in stress-related behaviors following LCI. Finally, LCI increased immunolabeling for FosB/deltaFosB (a protein associated with repeated or chronic neuronal activation) in the nucleus accumbens. These results indicate that palatable foods can provide stress blunting regardless of their sugar/carbohydrate composition, and support the idea that food reward per se contributes to stress relief.

Two hit mitochondrial-driven model of synapse loss in neurodegeneration

In healthy neurons, a mitochondrial membrane potential gradient exists whereby membrane potential is highest in the soma and decreases with distance from the nucleus. Correspondingly, distal mitochondria have more oxidative damage and slower protein import than somal mitochondria. Due to these differences, distal mitochondria have an intrinsic first stressor that somal mitochondria do not have, resulting in synaptic mitochondrial vulnerability. A second stressor may result from mutant protein expression, situational stress, or aging, exacerbating vulnerable mitochondria activating stress responses. Under these conditions, distal mitochondria release cytochrome c and mitochondrial DNA, leading to compartmentalized sub-lethal caspase-3 activation and cytokine production. In this two-hit mitochondrial-driven synaptic loss model, synapse vulnerability during neurodegeneration is explained as a superposition of pre-existing lower synaptic mitochondrial membrane potential (hit one) with additional mitochondrial stress (hit two). This two-hit mechanism occurs in synaptic mitochondria, activating signaling pathways leading to synaptic degeneration, as a potential preamble to neuronal death.

Fecal Transplant and Bifidobacterium Treatments Modulate Gut Clostridium Bacteria and Rescue Social Impairment and Hippocampal BDNF Expression in a Rodent Model of Autism

Autism is associated with gastrointestinal dysfunction and gut microbiota dysbiosis, including an overall increase in Clostridium. Modulation of the gut microbiota is suggested to improve autistic symptoms. In this study, we explored the implementation of two different interventions that target the microbiota in a rodent model of autism and their effects on social behavior: the levels of different fecal Clostridium spp., and hippocampal transcript levels. Autism was induced in young Sprague Dawley male rats using oral gavage of propionic acid (PPA) for three days, while controls received saline. PPA-treated animals were divided to receive either saline, fecal transplant from healthy donor rats, or Bifidobacterium for 22 days, while controls continued to receive saline. We found that PPA attenuated social interaction in animals, which was rescued by the two interventions. PPA-treated animals had a significantly increased abundance of fecal C. perfringens with a concomitant decrease in Clostridium cluster IV, and exhibited high hippocampal Bdnf expression compared to controls. Fecal microbiota transplantation or Bifidobacterium treatment restored the balance of fecal Clostridium spp. and normalized the level of Bdnf expression. These findings highlight the involvement of the gut-brain axis in the etiology of autism and propose possible interventions in a preclinical model of autism.

The role of sex-differentiated variations in stress hormones, antioxidants, and neuroimmune responses in relation to social interaction impairment in a rodent model of autism

Males are more likely to develop autism as a neurodevelopmental disorder than females, but the mechanisms underlying male susceptibility are not fully understood. In this paper, we used a well-characterized propionic acid (PPA) rodent model of autism to study sex differences in stress hormones, antioxidants' status, and the neuroimmune response that may contribute to the preponderance of autism in males. Sprague Dawley rats of both sexes were divided into a saline-treated group as controls and PPA-treated groups, receiving 250 mg/kg of PPA per day for three days. Animals' social behavior was examined using the three-chamber social test. Hormones (ACTH, corticosterone, melatonin, and oxytocin), oxidative stress biomarkers (glutathione, glutathione-S-transferase, and ascorbic acid), and cytokines (IL-6, IL-1α, IL-10, and IFNγ) were measured in the brain tissue of all the animals. The results showed a sex dimorphic social response to PPA treatment, where males were more susceptible to the PPA treatment and exhibited a significant reduction in social behavior with no effects observed in females. Also, sex differences were observed in the levels of hormones, antioxidants, and cytokines. Female rats showed significantly higher corticosterone and lower oxytocin, antioxidants, and cytokine levels than males. The PPA treatment later modulated these baseline differences. Our study indicates that the behavioral manifestation of autism in PPA-treated males and not females could be linked to neural biochemical differences between the sexes at baseline, which might play a protective role in females. Our results can contribute to early intervention strategies and treatments used to control autism, an increasingly prevalent disorder.

Early postnatal allergic airway inflammation induces dystrophic microglia leading to excitatory postsynaptic surplus and autism-like behavior

Microglia play key roles in synaptic pruning, which primarily occurs from the postnatal period to adolescence. Synaptic pruning is essential for normal brain development and its impairment is implicated in neuropsychiatric developmental diseases such as autism spectrum disorders (ASD). Recent epidemiological surveys reported a strong link between ASD and atopic/allergic diseases. However, few studies have experimentally investigated the relationship between allergy and ASD-like manifestations, particularly in the early postnatal period, when allergic disorders occur frequently. Therefore, we aimed to characterize how allergic inflammation in the early postnatal period influences microglia and behavior using mouse models of short- and long-term airway allergy. Male mice were immunized by an intraperitoneal injection of aluminum hydroxide and ovalbumin (OVA) or phosphate-buffered saline (control) on postnatal days (P) 3, 7, and 11, followed by intranasal challenge with OVA or phosphate-buffered saline solution twice a week until P30 or P70. In the hippocampus, Iba-1-positive areas, the size of Iba-1-positive microglial cell bodies, and the ramification index of microglia by Sholl analysis were significantly smaller in the OVA group than in the control group on P30 and P70, although Iba-1-positive microglia numbers did not differ significantly between the two groups. In Iba-1-positive cells, postsynaptic density protein 95 (PSD95)-occupied areas and CD68-occupied areas were significantly decreased on P30 and P70, respectively, in the OVA group compared with the control group. Immunoblotting using hippocampal tissues demonstrated that amounts of PSD95, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor 2, and N-methyl-D-aspartate (NMDA) receptor 2B were significantly increased in the OVA group compared with the control group on P70, and a similar increasing trend for PSD95 was observed on P30. Neurogenesis was not significantly different between the two groups on P30 or P70 by doublecortin immunohistochemistry. The social preference index was significantly lower in the three chamber test and the number of buried marbles was significantly higher in the OVA group than in the control group on P70 but not on P30, whereas locomotion and anxiety were not different between the two groups. Compared with the control group, serum basal corticosterone levels were significantly elevated and hippocampal glucocorticoid receptor (GR) amounts and nuclear GR translocation in microglia, but not in neurons or astrocytes, were significantly decreased in the OVA group on P70 but not on P30. Gene set enrichment analysis of isolated microglia revealed that genes related to immune responses including Toll-like receptor signaling and chemokine signaling pathways, senescence, and glucocorticoid signaling were significantly upregulated in the OVA group compared with the control group on P30 and P70. These findings suggest that early postnatal allergic airway inflammation induces dystrophic microglia that exhibit defective synaptic pruning upon short- and long-term allergen exposure. Furthermore, long-term allergen exposure induced excitatory postsynaptic surplus and ASD-like behavior. Hypothalamo-pituitary-adrenal axis activation and the compensatory downregulation of microglial GR during long-term allergic airway inflammation may also facilitate these changes.

Genetic disruption of Grm5 causes complex alterations in motor activity, anxiety and social behaviors

Autism is a neurodevelopmental disorder characterized by impaired social interactions and restricted and repetitive behaviors. Although group 1 metabotropic glutamate receptors (mGluRs), and in particular mGluR5, have been extensively proposed as potential targets for intervention in autism and other neurodevelopmental disorders, there has not been a comprehensive analysis of the effect of mGluR5 loss on behaviors typically assessed in autism mouse models thought to be correlates of behavioral symptoms of human disorders. Here we present a behavioral characterization of mice with complete or partial loss of mGluR5 (homozygous or heterozygous null mutations in Grm5 gene). We tested several autism related behaviors including social interaction, repetitive grooming, digging and locomotor behaviors. We found that digging and marble burying behaviors were almost completely abolished in mGluR5 ko mice, although self-grooming was not altered. Social interaction was impaired in ko but not in heterozygote (het) mice. In tests of locomotor activity and anxiety related behaviors, mGluR5 ko mice exhibited hyperactivity and reduced anxiety in the open field test but unexpectedly, showed hypoactivity in the elevated zero-maze test. There was no impairment in motor learning in the accelerating rotarod in both ko and het mutant. Together these results provide support for the importance of mGluR5 in motor and social behaviors that are specifically affected in autism disorders.

Osthole Ameliorates Estrogen Deficiency-Induced Cognitive Impairment in Female Mice

Loss of endogenous estrogen and dysregulation of the estrogen receptor signaling pathways are associated with an increase in risk for cognitive deficit and depression in women after menopause. Estrogen therapy for menopause increases the risk of breast and ovarian cancers, and stroke. Therefore, it is critical to find an alternate treatment for menopausal women. Osthole (OST), a coumarin, has been reported to have neuroprotective effects. This study examined whether OST improves ovariectomy (OVX)-induced cognitive impairment, and alleviates anxiety- and depression-like behaviors induced by OVX in mice. Adult female C57BL/6J mice were ovariectomized and then treated with OST at a dose of 30 mg/kg for 14 days. At the end of the treatment period, behavioral tests were used to evaluate spatial learning and memory, recognition memory, anxiety- and depression-like behaviors. A cohort of the mice were sacrificed after 14 days of OST treatment and their hippocampi were collected for measurement of the proteins of interest using western blot. OVX-induced alteration in the levels of proteins was accompanied by cognitive deficit, anxiety- and depression-like behaviors. OST treatment improved cognitive deficit, alleviated anxiety- and depression-like behaviors induced by OVX, and reversed OVX-induced alterations in the levels of synaptic proteins and ERα, BDNF, TrKB, p-CREB, p-Akt and Rac1 in the hippocampus. Therefore, reversal of OVX-induced decrease in the levels of hippocampal proteins by OST might contribute to the effects of OST on improving cognitive deficit and alleviating anxiety- and depression-like behaviors induced by OVX.

Long-Lasting Impact of Maternal Immune Activation and Interaction With a Second Immune Challenge on Pig Behavior

The combined effects on pig behavior of maternal immune challenge during gestation followed by a second immune challenge later in life have not been studied. Porcine reproductive and respiratory syndrome virus (PRRSV) infection during gestation can elicit maternal immune activation (MIA) yet the interactions with the offspring response to a second immune challenge after birth remains unexplored. Knowledge on the response to viral challenges in rodents has been gained through the use of the viral mimetic polyinosinic-polycytidylic acid (Poly(I:C)), yet the effects of this immune stimulant on pig behavior have not been assessed. This study advances the understanding of the combined effect of MIA and a second immune challenge later in life on female and male pig behavior. Three complementary experiments enabled the development of an effective Poly(I:C) challenge in pigs, and testing the interaction between PRRSV-elicited MIA, Poly(I:C) challenge at 60 days of age, and sex on behaviors. Individual-level observations on sickness, locomotor, and social behaviors were measured 1-3 h after Poly(I:C) challenge. Vomiting, panting, lethargy, walking, laying, playing, and touching behaviors were analyzed using generalized linear mixed effect models. Results indicated that a Poly(I:C) dose of 1 mg/kg within 1 h after injection increased the incidence of laying and sickness behavior. The Poly(I:C) challenge decreased the incidence of locomotor behaviors and activity levels. Pigs exposed to MIA had lower rates of social behaviors such as playing. The combined effect of PRRSV-elicited MIA and Poly(I:C) immune challenge further sensitized the pigs to behavior disruption across sexes including changes in sternal and lateral laying, walking, lethargy, and touching incidence. Notably, the effects of Poly(I:C) immune challenge alone on behaviors tended to be more extreme in males, whereas the effects of Poly(I:C) following MIA tended to be more extreme in females. Our findings demonstrate that MIA and Poly(I:C) affected behaviors, and the viral mimetic effects shortly after injection can offer insights into the prolonged effect of postnatal viral infections on feeding, social interactions and health status. Management practices that reduce the likelihood of gestational diseases and accommodate for behavioral disruptions in the offspring can minimize the impact of MIA.

Paired fruit flies synchronize behavior: Uncovering social interactions in Drosophila melanogaster

Social behaviors are ubiquitous and crucial to an animal's survival and success. The behaviors an animal performs in a social setting are affected by internal factors, inputs from the environment, and interactions with others. To quantify social behaviors, we need to measure both the stochastic nature of the behavior of isolated individuals and how this behavioral repertoire changes as a function of the environment and interactions between individuals. We probed the behavior of male and female fruit flies in a circular arena as individuals and within all possible pairings. By combining measurements of the animals' position in the arena with an unsupervised analysis of their behaviors, we define the effects of position in the environment and the presence of a partner on locomotion, grooming, singing, and other behaviors that make up an animal's repertoire. We find that geometric context tunes behavioral preference, pairs of animals synchronize their behavioral preferences across shared trials, and paired individuals display signatures of behavioral mimicry.

Mapping gene expression in social anxiety reveals the main brain structures involved in this disorder

Social Anxiety Disorder (SAD) is characterized by emotional and attentional biases as well as distorted negative self-beliefs. According this, we proposed to identify the brain structures and hub genes involved in SAD. An analysis in Pubmed and TRANSFAC was conducted and 72 genes were identified. Using Microarray data, from Allen Human Brain Atlas, it was possible to identify three modules of co-expressed genes from our gene set (R package WGCNA). Higher mean gene expression was found in cortico-medial group, basomedial nucleus, ATZ in amygdala and in head and tail of the caudate nucleus, nucleus accumbens and putamen in striatum. Our enrichment analysis identified the followed hub genes: DRD2, HTR1A, JUN, SP1 and HDAC4. We suggest that SAD is explained by delayed extinction of circuitry for conditioned fear. Caused by reduced activation of the dopaminergic and serotonergic systems,due diminished expectation of reward during social interactions.

Sex-linked roles of the CRF1 and the CRF2 receptor in social behavior

Dysfunctional social behavior is a major clinical feature of mood, anxiety, autism spectrum, and substance-related disorders, and may dramatically contribute to the poor outcome of these diseases. Nevertheless, the mechanisms underlying social behavior deficits are still largely unknown. The corticotropin-releasing factor (CRF) system, a major coordinator of the stress response, has been hypothesized to modulate social behavior. CRF signaling is mediated by two receptor types, termed CRF₁ and CRF₂ . Using the three-chamber task for sociability (i.e., preference for an unfamiliar conspecific vs. an object), this study demonstrates that CRF₂ receptor null mutation (CRF₂ -/-) reduces sociability in female mice but increases it in male mice. Both female and male CRF₂ -/- mice display a preference for social odor cues over neutral cues, indicating that sex- and CRF₂ receptor-dependent sociability is not due to altered olfaction or impaired social cues discrimination. Moreover, treatment with the CRF₁ receptor-preferring antagonist, antalarmin, consistently induces sociability in non-social mice but disrupts it in social mice, independently of CRF₂ receptor deficiency. Sex, CRF₂ receptor deficiency, or antalarmin affect locomotor activity during the three-chamber test. However, throughout the study CRF₁ and CRF₂ receptor-linked sociability is independent of locomotor activity. The present findings highlight major functions for the CRF system in the regulation of social behavior. Moreover, they provide initial evidence of sex-linked roles for the CRF₁ and the CRF₂ receptor, emphasizing the importance of sex as a major biological variable to be taken into consideration in preclinical and clinical studies.

IRSp53 Deletion in Glutamatergic and GABAergic Neurons and in Male and Female Mice Leads to Distinct Electrophysiological and Behavioral Phenotypes

IRSp53 (also known as BAIAP2) is an abundant excitatory postsynaptic scaffolding protein implicated in autism spectrum disorders (ASD), schizophrenia, and attention-deficit/hyperactivity disorder (ADHD). IRSp53 is expressed in different cell types across different brain regions, although it remains unclear how IRSp53 deletion in different cell types affects brain functions and behaviors in mice. Here, we deleted IRSp53 in excitatory and inhibitory neurons in mice and compared resulting phenotypes in males and females. IRSp53 deletion in excitatory neurons driven by Emx1 leads to strong social deficits and hyperactivity without affecting anxiety-like behavior, whereas IRSp53 deletion in inhibitory neurons driven by Viaat has minimal impacts on these behaviors in male mice. In female mice, excitatory neuronal IRSp53 deletion induces hyperactivity but moderate social deficits. Excitatory neuronal IRSp53 deletion in male mice induces an increased ratio of evoked excitatory and inhibitory synaptic transmission (E/I ratio) in layer V pyramidal neurons in the prelimbic region of the medial prefrontal cortex (mPFC), whereas the same mutation does not alter the E/I ratio in female neurons. These results suggest that IRSp53 deletion in excitatory and inhibitory neurons and in male and female mice has distinct impacts on behaviors and synaptic transmission.

TIAM2S as a novel regulator for serotonin level enhances brain plasticity and locomotion behavior

TIAM2S, the short form of human T-cell lymphoma invasion and metastasis 2, can have oncogenic effects when aberrantly expressed in the liver or lungs. However, it is also abundant in healthy, non-neoplastic brain tissue, in which its primary function is still unknown. Here, we examined the neurobiological and behavioral significance of human TIAM2S using the human brain protein panels, a human NT2/D1-derived neuronal cell line model (NT2/N), and transgenic mice that overexpress human TIAM2S (TIAM2S-TG). Our data reveal that TIAM2S exists primarily in neurons of the restricted brain areas around the limbic system and in well-differentiated NT2/N cells. Functional studies revealed that TIAM2S has no guanine nucleotide exchange factor (GEF) activity and is mainly located in the nucleus. Furthermore, whole-transcriptome and enrichment analysis with total RNA sequencing revealed that TIAM2S-knockdown (TIAM2S-KD) was strongly associated with the cellular processes of the brain structural development and differentiation, serotonin-related signaling, and the diseases markers representing neurobehavioral developmental disorders. Moreover, TIAM2S-KD cells display decreased neurite outgrowth and reduced serotonin levels. Moreover, TIAM2S overexpressing TG mice show increased number and length of serotonergic fibers at early postnatal stage, results in higher serotonin levels at both the serum and brain regions, and higher neuroplasticity and hyperlocomotion in latter adulthood. Taken together, our results illustrate the non-oncogenic functions of human TIAM2S and demonstrate that TIAM2S is a novel regulator of serotonin level, brain neuroplasticity, and locomotion behavior.

Pharmacological (ethanol) and mutation (sam2 KO) induced impairment of novelty preference in zebrafish quantified using a new three-chamber social choice task

Social behavior is a fundamental aspect of our own species, a feature without which our society would not function. There are numerous human brain disorders associated with abnormal social behavior, among them are the autism spectrum disorders whose causal factors include a genetic component. Environmental factors, including drugs of abuse such as alcohol, also contribute to numerous abnormalities related to social behavior. Several such disorders have been modeled using laboratory animals. Perhaps one of the newest among them is the zebrafish. However, the paucity of standardized behavioral assays specifically developed for the zebrafish have hindered progress. Here, we present a newly developed zebrafish behavioral paradigm, the three-chamber social choice task. This task, which was adapted from a murine model, assesses sociality and social novelty preference in zebrafish in three phases: habituation, phase-I to evaluate sociality, and phase-II to quantify social novelty preference. Test fish are placed in the middle chamber, while conspecifics are introduced to the flanking chambers during phase-I and II. Both male and female zebrafish displayed sociality (preference for conspecifics) during phase-I and social novelty preference (preference for unfamiliar conspecifics) during phase-II. We found the paradigm to be able to detect both environmentally (alcohol) as well as genetically (targeted knock out of sam2) induced alterations of behavioral phenotypes. Although ethanol-treated fish displayed similar levels of sociality to those of control (not alcohol exposed) male and female zebrafish, they were found to exhibit significantly impaired social novelty preference, a finding compatible with altered motivational or perhaps mnemonic processes. Moreover, we found that knock out of sam2, previously shown to lead to emotional dysregulation, also disrupted social novelty preference, while leaving sociality relatively intact. We conclude that our novel behavioral paradigm is appropriate for the modeling and quantification of social behavior deficits in zebrafish.

Radiofrequency electromagnetic radiation exposure effects on amygdala morphology, place preference behavior and brain caspase-3 activity in rats

The purpose of the study was to evaluate the changes in amygdala morphology and emotional behaviors, upon exposure to chronic RF-EMR in adolescent rats. Four weeks old male albino Wistar rats were exposed to 900 MHz (power density:146.60 μW/cm2) from a mobile phone in silent-mode for 28 days. Amygdala morphology was studied using cresyl violet, TUNEL and Golgi-Cox staining. Place preference behavior was studied using light/dark chamber test and following this brain caspase-3 activity was determined. Number of healthy neurons was decreased in the basolateral amygdala and cortical amygdala but not in the central amygdala after RF-EMR exposure. It also induced apoptosis in the amygdala. RF-EMR exposure altered dendritic arborization pattern in basolateral amygdala but not in the central amygdala. Altered place preference and hyperactivity-like behavior was evident after RF-EMR exposure, but brain caspase-3 activity did not change. RF-EMR exposure perturbed normal cellular architecture of amygdala and this was associated with altered place preference.

Sex differences in the developing brain as a source of inherent risk

Brain development diverges in males and females in response to androgen production by the fetal testis. This sexual differentiation of the brain occurs during a sensitive window and induces enduring neuroanatomical and physiological changes that profoundly impact behavior. What we know about the contribution of sex chromosomes is still emerging, highlighting the need to integrate multiple factors into understanding sex differences, including the importance of context. The cellular mechanisms are best modeled in rodents and have provided both unifying principles and surprising specifics. Markedly distinct signaling pathways direct differentiation in specific brain regions, resulting in mosaicism of relative maleness, femaleness, and sameness through-out the brain, while canalization both exaggerates and constrains sex differences. Non-neuronal cells and inflammatory mediators are found in greater number and at higher levels in parts of male brains. This higher baseline of inflammation is speculated to increase male vulnerability to developmental neuropsychiatric disorders that are triggered by inflammation.

Loss of FMRP Impaired Hippocampal Long-Term Plasticity and Spatial Learning in Rats

Fragile X syndrome (FXS) is a neurodevelopmental disorder caused by mutations in the FMR1 gene that inactivate expression of the gene product, the fragile X mental retardation 1 protein (FMRP). In this study, we used clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) technology to generate Fmr1 knockout (KO) rats by disruption of the fourth exon of the Fmr1 gene. Western blotting analysis confirmed that the FMRP was absent from the brains of the Fmr1 KO rats (Fmr1^exon4-KO ). Electrophysiological analysis revealed that the theta-burst stimulation (TBS)-induced long-term potentiation (LTP) and the low-frequency stimulus (LFS)-induced long-term depression (LTD) were decreased in the hippocampal Schaffer collateral pathway of the Fmr1^exon4-KO rats. Short-term plasticity, measured as the paired-pulse ratio, remained normal in the KO rats. The synaptic strength mediated by the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) was also impaired. Consistent with previous reports, the Fmr1^exon4-KO rats demonstrated an enhanced 3,5-dihydroxyphenylglycine (DHPG)-induced LTD in the present study, and this enhancement is insensitive to protein translation. In addition, the Fmr1^exon4-KO rats showed deficits in the probe trial in the Morris water maze test. These results demonstrate that deletion of the Fmr1 gene in rats specifically impairs long-term synaptic plasticity and hippocampus-dependent learning in a manner resembling the key symptoms of FXS. Furthermore, the Fmr1^exon4-KO rats displayed impaired social interaction and macroorchidism, the results consistent with those observed in patients with FXS. Thus, Fmr1^exon4-KO rats constitute a novel rat model of FXS that complements existing mouse models.

Supervised and Unsupervised Learning Technology in the Study of Rodent Behavior

Quantifying behavior is a challenge for scientists studying neuroscience, ethology, psychology, pathology, etc. Until now, behavior was mostly considered as qualitative descriptions of postures or labor intensive counting of bouts of individual movements. Many prominent behavioral scientists conducted studies describing postures of mice and rats, depicting step by step eating, grooming, courting, and other behaviors. Automated video assessment technologies permit scientists to quantify daily behavioral patterns/routines, social interactions, and postural changes in an unbiased manner. Here, we extensively reviewed published research on the topic of the structural blocks of behavior and proposed a structure of behavior based on the latest publications. We discuss the importance of defining a clear structure of behavior to allow professionals to write viable algorithms. We presented a discussion of technologies that are used in automated video assessment of behavior in mice and rats. We considered advantages and limitations of supervised and unsupervised learning. We presented the latest scientific discoveries that were made using automated video assessment. In conclusion, we proposed that the automated quantitative approach to evaluating animal behavior is the future of understanding the effect of brain signaling, pathologies, genetic content, and environment on behavior.

Tunable particles alter macrophage uptake based on combinatorial effects of physical properties

The ability to tune phagocytosis of particle-based therapeutics by macrophages can enhance their delivery to macrophages or reduce their phagocytic susceptibility for delivery to non-phagocytic cells. Since phagocytosis is affected by the physical and chemical properties of particles, it is crucial to identify any interplay between physical properties of particles in altering phagocytic interactions. The combinatorial effect of physical properties size, shape and stiffness was investigated on Fc receptor mediated macrophage interactions by fabrication of layer-by-layer tunable particles of constant surface chemistry. Our results highlight how changing particle stiffness affects phagocytic interaction intricately when combined with varying size or shape. Increase in size plays a dominant role over reduction in stiffness in reducing internalization by macrophages for spherical particles. Internalization of rod-shaped, but not spherical particles, was highly dependent on stiffness. These particles demonstrate the interplay between size, shape and stiffness in interactions of Fc-functionalized particles with macrophages during phagocytosis.

Convergence of Sex Differences and the Neuroimmune System in Autism Spectrum Disorder

The male bias in autism spectrum disorder incidence is among the most extreme of all neuropsychiatric disorders, yet the origins of the sex difference remain obscure. Developmentally, males are exposed to high levels of testosterone and its byproduct, estradiol. Together these steroids modify the course of brain development by altering neurogenesis, cell death, migration, differentiation, dendritic and axonal growth, synaptogenesis, and synaptic pruning, all of which can be deleteriously impacted during the course of developmental neuropsychiatric disorders. Elucidating the cellular mechanisms by which steroids modulate brain development provides valuable insights into how these processes may go awry. An emerging theme is the role of inflammatory signaling molecules and the innate immune system in directing brain masculinization, the evidence for which we review here. Evidence is also emerging that the neuroimmune system is overactivated in individuals with autism spectrum disorder. These combined observations lead us to propose that the natural process of brain masculinization puts males at risk by moving them closer to a vulnerability threshold that could more easily be breached by inflammation during critical periods of brain development. Two brain regions are highlighted: the preoptic area and the cerebellum. Both are developmentally regulated by the inflammatory prostaglandin E2, but in different ways. Microglia, innate immune cells of the brain, and astrocytes are also critical contributors to masculinization and illustrate the importance of nonneuronal cells to the health of the developing brain.

Chronic psychological stress and high-fat high-fructose diet disrupt metabolic and inflammatory gene networks in the brain, liver, and gut and promote behavioral deficits in mice

The mechanisms underlying the association between chronic psychological stress, development of metabolic syndrome (MetS), and behavioral impairment in obesity are poorly understood. The aim of the present study was to assess the effects of mild chronic psychological stress on metabolic, inflammatory, and behavioral profiles in a mouse model of diet-induced obesity. We hypothesized that (1) high-fat high-fructose diet (HFHF) and psychological stress would synergize to mediate the impact of inflammation on the central nervous system in the presence of behavioral dysfunction, and that (2) HFHF and stress interactions would impact insulin and lipid metabolism. C57Bl/6 male mice underwent a combination of HFHF and two weeks of chronic psychological stress. MetS-related conditions were assessed using untargeted plasma metabolomics, and structural and immune changes in the gut and liver were evaluated. Inflammation was measured in plasma, liver, gut, and brain. Our results show a complex interplay of diet and stress on gut alterations, energetic homeostasis, lipid metabolism, and plasma insulin levels. Psychological stress and HFHF diet promoted changes in intestinal tight junctions proteins and increases in insulin resistance and plasma cholesterol, and impacted the RNA expression of inflammatory factors in the hippocampus. Stress promoted an adaptive anti-inflammatory profile in the hippocampus that was abolished by diet treatment. HFHF increased hippocampal and hepatic Lcn2 mRNA expression as well as LCN2 plasma levels. Behavioral changes were associated with HFHF and stress. Collectively, these results suggest that diet and stress as pervasive factors exacerbate MetS-related conditions through an inflammatory mechanism that ultimately can impact behavior. This rodent model may prove useful for identification of possible biomarkers and therapeutic targets to treat metabolic syndrome and mood disorders.

Characterization of AD-like phenotype in aged APPSwe/PS1dE9 mice

Transgenic APPSwe/PS1dE9 (APP/PS1) mice that overproduce amyloid beta (Aβ) are extensively used in the studies of pathogenesis and experimental therapeutics and new drug screening for Alzheimer's disease (AD). However, most of the current literature uses young or adult APP/PS1 mice. In order to provide a broader view of AD-like phenotype of this animal model, in this study, we systematically analyzed behavioral and pathological profiles of 24-month-old male APP/PS1 mice. Aged APP/PS1 mice had reference memory deficits as well as anxiety, hyperactivity, and social interaction impairment. Consistently, there was obvious deposition of amyloid plaques in the dorsal hippocampus with decreased expression of insulin-degrading enzyme, a proteolytic enzyme responsible for degradation of intracellular Aβ. Furthermore, decreases in hippocampal volume, neuronal number and synaptophysin expression, and astrocyte atrophy were also observed in aged APP/PS1 mice. This finding suggests that aged APP/PS1 mice can well replicate cognitive and noncognitive behavioral abnormalities, hippocampal atrophy, and neuronal and astrocyte degeneration in AD patients, to enable more objective and refined preclinical evaluation of therapeutic drugs and strategies for AD treatment.