Perinatal exposure to benzyl butyl phthalate induces alterations in neuronal development/maturation protein expression, estrogen responses, and fear conditioning in rodents.

Phthalate exposure has recently been associated with behavioral actions that are linked to its endocrine-disrupting properties. The purpose of this study was to investigate the molecular, anatomical, and behavioral effects of indirect perinatal benzyl butyl phthalate (BBP) exposure in offspring of BBP-treated pregnant dams. In two separate experiments, we administered BBP (10.0 µg/ml) on food pellets to pregnant dams and examined the offspring. The first experiment revealed reproductive anatomical abnormalities linked to BBP's endocrine-disrupting properties, whereas histological analysis revealed preserved hippocampal neuronal migration. The second experiment demonstrated learning and memory impairments accompanied by molecular abnormalities in multiple brain regions. Offspring from BBP-treated dams had altered levels of several proteins important for neuronal circuitry formation, tissue development, and maturation. We suggest that BBP administration disrupts normal learning and that these effects could be related to alterations in brain development and result in a phenotype similar to that observed in neurodevelopmental disorders.

Differentially disrupted spinal cord and muscle energy metabolism in spinal and bulbar muscular atrophy.

Prior studies showed that polyglutamine-expanded androgen receptor (AR) is aberrantly acetylated and that deacetylation of the mutant AR by overexpression of nicotinamide adenine dinucleotide-dependent (NAD+-dependent) sirtuin 1 is protective in cell models of spinal and bulbar muscular atrophy (SBMA). Based on these observations and reduced NAD+ in muscles of SBMA mouse models, we tested the therapeutic potential of NAD+ restoration in vivo by treating postsymptomatic transgenic SBMA mice with the NAD+ precursor nicotinamide riboside (NR). NR supplementation failed to alter disease progression and had no effect on increasing NAD+ or ATP content in muscle, despite producing a modest increase of NAD+ in the spinal cords of SBMA mice. Metabolomic and proteomic profiles of SBMA quadriceps muscles indicated alterations in several important energy-related pathways that use NAD+, in addition to the NAD+ salvage pathway, which is critical for NAD+ regeneration for use in cellular energy production. We also observed decreased mRNA levels of nicotinamide riboside kinase 2 (Nmrk2), which encodes a key kinase responsible for NR phosphorylation, allowing its use by the NAD+ salvage pathway. Together, these data suggest a model in which NAD+ levels are significantly decreased in muscles of an SBMA mouse model and intransigent to NR supplementation because of decreased levels of Nmrk2.

Chronic exposure to benzyl butyl phthalate (BBP) alters social interaction and fear conditioning in male adult rats: alterations in amygdalar MeCP2, ERK1/2 and ERα.

OBJECTIVES: Benzyl Butyl Phthalate (BBP) is an industrial plasticizer that has an unknown action in the central nervous system. Phthalates have recently been associated with behavioral actions that are linked to their endocrine disrupting properties. The purpose of this study was to investigate the behavioral and molecular effects of BBP treatment in male rats. DESIGN: Male rats were chronically exposed to BBP in the drinking water (5.0 ppm and 10.0 ppm) throughout adolescence and into the adult phase of life. Their behavior was then assessed in a learning and memory task (fear conditioning), open field exploration and a test of sociability. RESULTS: BBP treated rats showed decreased freezing in fear conditioning, no changes in open field exploration, and increased aberrant social behavior. Rats were sacrificed at post natal day 140 and blood and brains were harvested and processed. We found increased hormonally active estrogen, 17-ß estradiol, in the serum of BBP treated rats. BBP treatment also induced changes in amygdalar proteins related to synaptic plasticity including decreased MeCP2 levels that correlated with tests of sociability with no changes in stress related proteins such as nuclear factor kappa B (NFkB). We also found alterations in physiological responses as measured by body weight without changes in food consumption suggesting disruption of metabolism and body homeostasis. CONCLUSIONS: We suggest that BBP administration disrupts normal learning and social behavior, and that these effects could be related to alterations of amygdala function.

Axonal localization of the fragile X family of RNA binding proteins is conserved across mammals.

Spatial segregation of proteins to neuronal axons arises in part from local translation of mRNAs that are first transported into axons in ribonucleoprotein particles (RNPs), complexes containing mRNAs and RNA binding proteins. Understanding the importance of local translation for a particular circuit requires not only identifying axonal RNPs and their mRNA cargoes, but also whether these RNPs are broadly conserved or restricted to only a few species. Fragile X granules (FXGs) are axonal RNPs containing the fragile X related family of RNA binding proteins along with ribosomes and specific mRNAs. FXGs were previously identified in mouse, rat, and human brains in a conserved subset of neuronal circuits but with species-dependent developmental profiles. Here, we asked whether FXGs are a broadly conserved feature of the mammalian brain and sought to better understand the species-dependent developmental expression pattern. We found FXGs in a conserved subset of neurons and circuits in the brains of every examined species that together include mammalian taxa separated by up to 160 million years of divergent evolution. A developmental analysis of rodents revealed that FXG expression in frontal cortex and olfactory bulb followed consistent patterns in all species examined. In contrast, FXGs in hippocampal mossy fibers increased in abundance across development for most species but decreased across development in guinea pigs and members of the Mus genus, animals that navigate particularly small home ranges in the wild. The widespread conservation of FXGs suggests that axonal translation is an ancient, conserved mechanism for regulating the proteome of mammalian axons.

Differential expression of the T-cell inhibitor TIGIT in glioblastoma and MS.

OBJECTIVE: To identify coinhibitory immune pathways important in the brain, we hypothesized that comparison of T cells in lesions from patients with MS with tumor-infiltrating T cells (TILs) from patients with glioblastoma multiforme may reveal novel targets for immunotherapy. METHODS: We collected fresh surgical resections and matched blood from patients with glioblastoma, blood and unmatched postmortem CNS tissue from patients with MS, and blood from healthy donors. The expression of TIGIT, CD226, and their shared ligand CD155 as well as PD-1 and PDL1 was assessed by both immunohistochemistry and flow cytometry. RESULTS: We found that TIGIT was highly expressed on glioblastoma-infiltrating T cells, but was near-absent from MS lesions. Conversely, lymphocytic expression of PD-1/PD-L1 was comparable between the 2 diseases. Moreover, TIGIT was significantly upregulated in circulating lymphocytes of patients with glioblastoma compared with healthy controls, suggesting recirculation of TILs. Expression of CD226 was also increased in glioblastoma, but this costimulatory receptor was expressed alongside TIGIT in the majority of tumor-infiltrating T cells, suggesting functional counteraction. CONCLUSIONS: The opposite patterns of TIGIT expression in the CNS between MS and glioblastoma reflects the divergent features of the immune response in these 2 CNS diseases. These data raise the possibility that anti-TIGIT therapy may be beneficial for patients with glioblastoma.