Treatment of a mouse model of spinal cord injury by transplantation of human induced pluripotent stem cell-derived long-term self-renewing neuroepithelial-like stem cells

Because of their ability to self-renew, to differentiate into multiple lineages, and to migrate toward a damaged site, neural stem cells (NSCs), which can be derived from various sources such as fetal tissues and embryonic stem cells, are currently considered to be promising components of cell replacement strategies aimed at treating injuries of the central nervous system, including the spinal cord. Despite their efficiency in promoting functional recovery, these NSCs are not homogeneous and possess variable characteristics depending on their derivation protocols. The advent of induced pluripotent stem (iPS) cells has provided new prospects for regenerative medicine. We used a recently developed robust and stable protocol for the generation of long-term, self-renewing, neuroepithelial-like stem cells from human iPS cells (hiPS-lt-NES cells), which can provide a homogeneous and well-defined population of NSCs for standardized analysis. Here, we show that transplanted hiPS-lt-NES cells differentiate into neural lineages in the mouse model of spinal cord injury (SCI) and promote functional recovery of hind limb motor function. Furthermore, using two different neuronal tracers and ablation of the transplanted cells, we revealed that transplanted hiPS-lt-NES cell-derived neurons, together with the surviving endogenous neurons, contributed to restored motor function. Both types of neurons reconstructed the corticospinal tract by forming synaptic connections and integrating neuronal circuits. Our findings indicate that hiPS-lt-NES transplantation represents a promising avenue for effective cell-based treatment of SCI.     

Ultrastructural changes in cerebral capillary pericytes in aged Notch3 mutant transgenic mice

Pericytes, the specialized vascular smooth muscle cells (VSMCs), play an important role in supporting and maintaining the structure of capillaries. Pericytes show biochemical and physiologic features similar to VSMC, usually containing smooth muscle actin fibers and rich endoplasm reticulum. Studies have indicated that degeneration of VSMCs due to Notch3 mutations is the cause of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). However, it remains unclear whether the Notch3 mutation also affects cerebral cortex capillary pericytes. In this ultrastructural morphologic study, the authors have observed pathological changes in the cerebral cortex capillary pericytes in aged mice that carry human mutant Notch3 genes. The number of abnormal pericytes in the cerebral cortex in Notch3 gene mutant mice was slightly increased when compared to an age-matched control group. Morphologically, the pericytes in the brains of Notch3 gene mutant mice showed more severe cellular injury, such as the presence of damaged mitochondria, secondary lysosomes, and large cytoplasmic vesicles. In addition, morphologic structures related to autophagy were also present in the pericytes of Notch3 gene mutant group. These ultrastructural morphologic alterations suggest that Notch3 mutation precipitates age-related pericytic degeneration that might result in cellular injury and trigger autophagic apoptosis. Microvascular dysfunction due to pericyte degeneration could initiate secondary neurodegenerative changes in brain parenchyma. These findings provide new insight into understanding the role of pericyte degeneration in the phathogenesis of CADASIL disease.     

A new synthetic TLR4 agonist, GLA, allows dendritic cells targeted with antigen to elicit Th1 T-cell immunity in vivo

Protein‐based vaccines offer safety and cost advantages but require adjuvants to induce immunity. Here we examined the adjuvant capacity of glucopyranosyl lipid A (GLA), a new synthetic non‐toxic analogue of lipopolysaccharide. In mice, in comparison with non‐formulated LPS and monophosphoryl lipid A, formulated GLA induced higher antibody titers and generated Type 1 T‐cell responses to HIV gag‐p24 protein in spleen and lymph nodes, which was dependent on TLR4 expression. Immunization was greatly improved by targeting HIV gag p24 to DCs with an antibody to DEC‐205, a DC receptor for antigen uptake and processing. Subcutaneous immunization induced antigen‐specific T‐cell responses in the intestinal lamina propria. Immunity did not develop in mice transiently depleted of DCs. To understand how GLA works, we studied DCs directly from vaccinated mice. Within 4 h, GLA caused DCs to upregulate CD86 and CD40 and produce cytokines including IL‐12p70 in vivo. Importantly, DCs removed from mice 4 h after vaccination became immunogenic, capable of inducing T‐cell immunity upon injection into naïve mice. These data indicate that a synthetic and clinically feasible TLR4 agonist rapidly stimulates full maturation of DCs in vivo, allowing for adaptive immunity to develop many weeks to months later.     

S100A9 a new marker for monocytic human myeloid-derived suppressor cells

Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of cells that negatively regulate the immune response during tumour progression, inflammation and infection. Only limited data are available on human MDSC because of the lack of specific markers. We have identified members of the S100 protein family-S100A8, S100A9 and S100A12 - specifically expressed in CD14(+) HLA-DR(-/low) MDSC. S100A9 staining in combination with anti-CD14 could be used to identify MDSC in whole blood from patients with colon cancer. An increase in the population of CD14(+) S100A9(high) MDSC was observed in the peripheral blood from colon cancer patients in comparison with healthy controls. Finally, nitric oxide synthase expression, a hallmark of MDSC, was induced in CD14(+) S100A9(high) upon lipopolysaccharide/interferon-γ stimulation. We propose S100 proteins as useful markers for the analysis and further characterization of human MDSC.     

Screening high school students for eating disorders: validity of brief behavioral and attitudinal measures

BACKGROUND: Early identification can greatly impact the trajectory of eating disorders, and school‐based screening is 1 avenue for identifying those at risk. To be feasible in a school setting, a screening program must use a brief, valid screening tool. The aim of this study was to assess how well brief attitudinal and behavioral survey items identify adolescents at risk in a large sample of high school students from across the United States. METHODS: Data were drawn from the National Eating Disorder Screening Program, the first‐ever national eating disorders screening initiative for US high schools. A 2‐stage, clustered sampling method was used to randomly select a subset of student screening forms (n = 5740), which included the Eating Attitudes Test (EAT‐26), behavioral questions assessing the frequency of vomiting and binge eating in the past 3 months, and an attitudinal item that assessed preoccupation with thinness. RESULTS: Nearly 12% of females and 3% of males reported vomiting to control their weight and 17% of females and 10% of males reported binge eating 1 or more times per month. Approximately 24% of females and 8% of males report being preoccupied with being thinner. We found that the attitudinal measure yielded high sensitivity and specificity. Combined screening measures that used both the attitudinal and behavioral items yielded slightly higher sensitivity values than those found with the attitudinal measure alone. CONCLUSION: High school administrators should include items that assess both preoccupation with thinness as well as behavioral items that deal with eating disorders on student health surveys.     

The blind spot in the drive for childhood obesity prevention: bringing eating disorders prevention into focus as a public health priority

Public health attention to childhood obesity has increased in tandem with the growing epidemic, but despite this intense focus, successes in prevention have lagged far behind. There is a blind spot in our drive for childhood obesity prevention that prevents us from generating sufficiently broad solutions. Eating disorders and the constellation of perilous weight-control behaviors are in that blind spot. Evidence is mounting that obesity and eating disorders are linked in myriad ways, but entrenched myths about eating disorders undermine our ability to see the full range of leverage points to target in obesity preventive intervention studies. Our efforts to prevent childhood obesity can no longer afford to ignore eating disorders and the assemblage of related behaviors that persist unabated.     

High burden of homelessness among sexual-minority adolescents: findings from a representative Massachusetts high school sample

Objectives. We compared the prevalence of current homelessness among adolescents reporting a minority sexual orientation (lesbian/gay, bisexual, unsure, or heterosexual with same-sex sexual partners) with that among exclusively heterosexual adolescents.Methods. We combined data from the 2005 and 2007 Massachusetts Youth Risk Behavior Survey, a representative sample of public school students in grades 9 though 12 (n = 6317).Results. Approximately 25% of lesbian/gay, 15% of bisexual, and 3% of exclusively heterosexual Massachusetts public high school students were homeless. Sexual-minority males and females had an odds of reporting current homelessness that was between 4 and 13 times that of their exclusively heterosexual peers. Sexual-minority youths’ greater likelihood of being homeless was driven by their increased risk of living separately from their parents or guardians.Conclusions. Youth homelessness is linked with numerous threats such as violence, substance use, and mental health problems. Although discrimination and victimization related to minority sexual orientation status are believed to be important causal factors, research is needed to improve our understanding of the risks and protective factors for homelessness and to determine effective strategies to prevent homelessness in this population.Two distinct groups make up the population of homeless children and youths in the United States: (1) families with children and (2) unaccompanied youths.¹ Regarding the first group, it was estimated that more than 1.5 million US children lived within families that lacked a permanent home during the period of 2005 to 2006.¹ Regarding the second group, an additional 575 000 to 1.6 million US youths are estimated to be living without a home and without a family, unaccompanied on the streets or in a shelter.¹Youths with minority sexual orientations (such as those identifying themselves as gay, lesbian, or bisexual) appear to be disproportionately at risk for homelessness. A review of research on studies drawn from homeless (i.e., unaccompanied) youth samples found that this population was overrepresented in 17 of 22 studies.² Estimates of the proportion of the sample in the studies reviewed who were of a sexual minority varied widely, ranging from 4%–5% to 50%. Differences across these studies, such as sample recruitment methods, geographic location, participants’ ages, and definition of sexual-minority status likely explain much of this variability.Homelessness is positively linked with health threats such as victimization, physical and sexual abuse, mental health and substance use problems, and sexual risk behaviors.^3–6 Important differences in risk exist among homeless youths who live with their parents or guardians compared with those living separately from their primary caretakers; thus, it is important to examine how sexual orientation may be related to homeless status. Youths who are not physically or emotionally connected to their families have additional risks. For example, youths who are in the presence of their parents at key times during the day are less likely than are youths who are not around their parents to experience emotional distress and to use cigarettes, alcohol, and marijuana.⁷ Among homeless and at-risk youths, those reporting greater parental monitoring are less likely to report substance use.⁸ Homeless youths who have a positive relationship with their parents have a lower risk of engaging in substance use, criminal behavior, and survival sex than do homeless youths who report poorer relationships with their parents.⁹ Youths who are recently homeless have fewer sexual risk behaviors if they live with their families than if they live in situations without parental supervision and support.⁵Certain social factors place youths at an elevated risk for homelessness. At-risk youths include those who experience problems at home, are placed in foster care, or who are socioeconomically disadvantaged.⁶ In one study of 692 homeless youths aged between 12 and 20 years, more than 70% of the participants identified conflict with parents as an important reason for leaving home.¹⁰ Similarly, youths who experience emotional neglect or physical or sexual abuse are more likely to become homeless.^11,12 Youths displaying school adjustment problems such as poor academic achievement and disciplinary problems are also more likely than are youths who do well in school to be homeless.¹²Several factors associated with greater risk for homelessness have been found to occur more frequently in youths with minority sexual orientations than in heterosexual youths. For example, studies document a higher risk of familial childhood maltreatment among lesbian, gay, and bisexual individuals than among heterosexual individuals.^13–16 This population also faces an increased likelihood of experiencing discrimination and victimization in school and community settings^16,17 as well as diminished peer support.¹⁸ Middle and high school environments are frequently unsupportive of or hostile toward youths’ minority sexual orientation status,^19,20 which can contribute to poorer school outcomes among sexual-minority youths than among heterosexual youths.²¹Although evidence from studies focusing on homeless populations suggests that sexual-minority youths face a greater risk of homelessness than do heterosexual youths, studies using representative samples that are able to quantify the magnitude of the relative risk are scarce. A main reason for this research gap is that population-based surveys of youths generally lack questions on both homeless status and sexual orientation. Consequently, uncertainty exists as to the extent that studies that sample from homeless populations are generalizable to the larger population of youths.One representative sample of adolescents attending Massachusetts public high schools, the Youth Risk Behavior Survey (MAYRBS), contains information on homeless status and sexual orientation. We used data from this survey to estimate the prevalence of homelessness in sexual-minority adolescents (lesbian or gay, bisexual, heterosexual with same-sex sexual experience, or unsure of orientation) and in exclusively heterosexual adolescents and to estimate the relative risks of homelessness after controlling for potential demographic confounding. Although previous research on homelessness in sexual minority youths has focused on runaways,² we took a broader approach in the current analysis by defining homelessness on the basis of the definition outlined in the US federal McKinney–Vento Homeless Assistance Act (i.e., lacking a fixed, regular, and adequate nighttime residence). We examined overall homelessness and then investigated the possibility that sexual-minority adolescents would be more likely than exclusively heterosexual adolescents to be living without their parents or guardians. How sexual orientation may be related to these 2 groups of homeless youths (those living with parents or guardians and those not living with a primary caretaker) is important to examine because of the differences in risk profiles between these groups.     

Chemical genomics profiling of environmental chemical modulation of human nuclear receptors

Background: The large and increasing number of chemicals released into the environment demands more efficient and cost-effective approaches for assessing environmental chemical toxicity. The U.S. Tox21 program has responded to this challenge by proposing alternative strategies for toxicity testing, among which the quantitative high-throughput screening (qHTS) paradigm has been adopted as the primary tool for generating data from screening large chemical libraries using a wide spectrum of assays.Objectives: The goal of this study was to develop methods to evaluate the data generated from these assays to guide future assay selection and prioritization for the Tox21 program.Methods: We examined the data from the Tox21 pilot-phase collection of approximately 3,000 environmental chemicals profiled in qHTS format against a panel of 10 human nuclear receptors (AR, ERα, FXR, GR, LXRβ, PPARγ, PPARδ, RXRα, TRβ, and VDR) for reproducibility, concordance of biological activity profiles with sequence homology of the receptor ligand binding domains, and structure–activity relationships.Results: We determined the assays to be appropriate in terms of biological relevance. We found better concordance for replicate compounds for the agonist-mode than for the antagonist-mode assays, likely due to interference of cytotoxicity in the latter assays. This exercise also enabled us to formulate data-driven strategies for discriminating true signals from artifacts, and to prioritize assays based on data quality.Conclusions: The results demonstrate the feasibility of qHTS to identify the potential for environmentally relevant chemicals to interact with key toxicity pathways related to human disease induction.