Genome-wide screening reveals the genetic basis of mammalian embryonic eye development.

BACKGROUND: Microphthalmia, anophthalmia, and coloboma (MAC) spectrum disease encompasses a group of eye malformations which play a role in childhood visual impairment. Although the predominant cause of eye malformations is known to be heritable in nature, with 80% of cases displaying loss-of-function mutations in the ocular developmental genes OTX2 or SOX2, the genetic abnormalities underlying the remaining cases of MAC are incompletely understood. This study intended to identify the novel genes and pathways required for early eye development. Additionally, pathways involved in eye formation during embryogenesis are also incompletely understood. This study aims to identify the novel genes and pathways required for early eye development through systematic forward screening of the mammalian genome. RESULTS: Query of the International Mouse Phenotyping Consortium (IMPC) database (data release 17.0, August 01, 2022) identified 74 unique knockout lines (genes) with genetically associated eye defects in mouse embryos. The vast majority of eye abnormalities were small or absent eyes, findings most relevant to MAC spectrum disease in humans. A literature search showed that 27 of the 74 lines had previously published knockout mouse models, of which only 15 had ocular defects identified in the original publications. These 12 previously published gene knockouts with no reported ocular abnormalities and the 47 unpublished knockouts with ocular abnormalities identified by the IMPC represent 59 genes not previously associated with early eye development in mice. Of these 59, we identified 19 genes with a reported human eye phenotype. Overall, mining of the IMPC data yielded 40 previously unimplicated genes linked to mammalian eye development. Bioinformatic analysis showed that several of the IMPC genes colocalized to several protein anabolic and pluripotency pathways in early eye development. Of note, our analysis suggests that the serine-glycine pathway producing glycine, a mitochondrial one-carbon donator to folate one-carbon metabolism (FOCM), is essential for eye formation. CONCLUSIONS: Using genome-wide phenotype screening of single-gene knockout mouse lines, STRING analysis, and bioinformatic methods, this study identified genes heretofore unassociated with MAC phenotypes providing models to research novel molecular and cellular mechanisms involved in eye development. These findings have the potential to hasten the diagnosis and treatment of this congenital blinding disease

Mendelian gene identification through mouse embryo viability screening.

BACKGROUND: The diagnostic rate of Mendelian disorders in sequencing studies continues to increase, along with the pace of novel disease gene discovery. However, variant interpretation in novel genes not currently associated with disease is particularly challenging and strategies combining gene functional evidence with approaches that evaluate the phenotypic similarities between patients and model organisms have proven successful. A full spectrum of intolerance to loss-of-function variation has been previously described, providing evidence that gene essentiality should not be considered as a simple and fixed binary property. METHODS: Here we further dissected this spectrum by assessing the embryonic stage at which homozygous loss-of-function results in lethality in mice from the International Mouse Phenotyping Consortium, classifying the set of lethal genes into one of three windows of lethality: early, mid, or late gestation lethal. We studied the correlation between these windows of lethality and various gene features including expression across development, paralogy and constraint metrics together with human disease phenotypes. We explored a gene similarity approach for novel gene discovery and investigated unsolved cases from the 100,000 Genomes Project. RESULTS: We found that genes in the early gestation lethal category have distinct characteristics and are enriched for genes linked with recessive forms of inherited metabolic disease. We identified several genes sharing multiple features with known biallelic forms of inborn errors of the metabolism and found signs of enrichment of biallelic predicted pathogenic variants among early gestation lethal genes in patients recruited under this disease category. We highlight two novel gene candidates with phenotypic overlap between the patients and the mouse knockouts. CONCLUSIONS: Information on the developmental period at which embryonic lethality occurs in the knockout mouse may be used for novel disease gene discovery that helps to prioritise variants in unsolved rare disease cases

PD-1 expression is upregulated on adapted T cells in experimental autoimmune encephalomyelitis but is not required to maintain a hyporesponsive state

T cell adaptation is an important peripheral tolerogenic process which ensures that the T cell population can respond effectively to pathogens but remains tolerant to self-antigens. We probed the mechanisms of T cell adaptation using an experimental autoimmune encephalomyelitis (EAE) model in which the fate of autopathogenic T cells could be followed. We demonstrated that immunisation with a high dose of myelin basic protein (MBP) peptide and complete Freund's adjuvant failed to effectively initiate EAE, in contrast to low dose MBP peptide immunisation which readily induced disease. The proportion of autopathogenic CD4 + T cells in the central nervous system (CNS) of mice immunised with a high dose of MBP peptide was not significantly different to mice immunised with a low dose. However, autopathogenic T cells in mice immunised with high dose MBP peptide had an unresponsive phenotype in ex vivo recall assays. Importantly, whilst expression of PD-1 was increased on adapted CD4 + T cells within the CNS, loss of PD-1 function did not prevent the development of the unresponsive state. The lack of a role for PD-1 in the acquisition of the adapted state stands in striking contrast to the reported functional importance of PD-1 in T cell unresponsiveness in other disease models

The effects of graded levels of dietary carbohydrate on fetal and neonatal glucose metabolism

The effects of maternal dietary glucose restriction on reproductive performance were investigated by feeding pregnant rats isocaloric diets containing graded levels of dietary glucose (0, 12, 24 and 60%) during pregnancy and during pregnancy and lactation, and by measuring the effects of glucose restriction on (1) maternal, fetal and neonatal metabolism, on (2) growth and composition of the mammary glands and placentas, and (3) on milk composition. Carbohydrate restriction induced maternal metabolic adaptations that were proportional to the severity of the glucose restriction. Placental growth and composition as well as mammary gland composition were not affected by dietary glucose restriction, whereas fetal growth and development and milk composition were significantly impaired when glucose was limited in the maternal diet. This suggests that the effects of dietary glucose on the fetus and on milk composition were not mediated by changes in placenta and mammary gland DNA, protein or glycogen concentrations. Complete dietary glucose restriction significantly depressed fetal liver, lung and heart glycogen concentrations; repletion of the maternal diets with 12 and 24% glucose restored cardiac glycogen to normal but not fetal lung glycogen and liver glycogen. Pups born to dams fed a glucose-free diet failed to survive longer than 24 h postpartum and that was associated with the low levels of tissue glycogen at birth in these pups. At birth, lung and liver glycogen concentration of pups of the 12 and 24% glucose diets was similar to pups of the control diet despite the fact that these reserves were depressed in utero; and these pups efficiently corrected the transient hypoglycemia observed following parturition. The effects of glucose restriction on fetal liver glycogen were not reflected by similar changes in fetal plasma insulin, glucagon and glucose levels or in glycogen synthase and phosphorylase activities. Maternal dietary glucose was an important determinan

Reproductive and developmental outcomes, and influence on maternal and offspring tissue mineral concentrations, of (−)-epicatechin, (+)-catechin, and rutin ingestion prior to, and during pregnancy and lactation in C57BL/6J mice

Maternal nutrition can have a significant effect on developmental processes during pregnancy and lactation. While certain flavonoids have been postulated to be beneficial for health, little is known about the effects of ingestion during pregnancy and lactation on the mother and progeny. We report on the effects of maternal consumption of high levels of certain flavonoids on reproductive and developmental outcomes in a mouse model. C57BL/6J female mice were fed a control diet (CT), the CT diet supplemented with 1% or 2% of a mix of epicatechin and catechin (EC1, EC2), or rutin (RU1, RU2) prior to, during pregnancy, and lactation. A subset of dams was killed on gestation day (GD) 18.5 to evaluate fetal outcomes and the remainder was allowed to deliver to evaluate offspring. Maternal food intake, body and tissue weight did not differ among groups. The number of resorptions, implantations, litter size, postnatal survival, body weight, and skeletal development were also similar. Alterations in maternal and offspring liver mineral concentrations were observed. The current results indicate that consumption of high amounts of epicatechin, catechin, and rutin during gestation and lactation is not associated with any marked developmental effects, although changes in liver mineral concentrations were noted

Cross-Cultural Adaptation and Initial Validation of Mi Niño: A Tool to Measure Food-Related Parenting Practices of Spanish-Speaking Parents with Young Children

BackgroundAccurate measurement of food-related parenting practices is necessary to inform related interventions and program evaluation. Valid tools reflect cultural attributes that affect household food environments and feeding practices. Simple, unidirectional language adaptation approaches are insufficient to capture these attributes in assessment tools. My Child at Mealtime (MCMT) is a 27-item, validated, visually enhanced self-assessment tool to measure food-related parenting practices of low-income English-speaking parents of preschoolers.ObjectivesThe aim of this study was to describe the cross-cultural adaptation of MCMT into its Spanish version Mi Niño a la Hora the Comer (Mi Niño) and to establish its face validity, factor structure, and internal consistency.MethodsMCMT was adapted into its Spanish version after an iterative process that triangulated cognitive interviews with verification of conceptual equivalence by content experts to establish face validity and semantic equivalence. The resulting tool underwent confirmatory factor analysis to determine whether internal consistency was equivalent across the 2 versions.ResultsFour rounds of cognitive interviews (n = 5, n = 6, n = 2, and n = 4, respectively) with Spanish-speaking women caregivers of children aged 3-5 y recruited from Head Start were conducted. Ten items were modified throughout the adaptation process. Modifications included improved clarity (6 items), comprehension (7 items), appropriateness (4 items), suitability (4 items), and usefulness (2 items) of text and/or accompanying visuals. Confirmatory factor analysis with a sample of Spanish-speaking caregivers (n = 243) resulted in 2 reliable factors representing "child-centered" (α = 0.82) and "parent-centered" (α = 0.87) food-related parenting practices.ConclusionsFace validity, semantic equivalence, and internal consistency of Mi Niño were established. This tool can be used in community settings to inform program content and measure changes in food-related parenting practices of Spanish-speaking parents and assist in setting food-related parenting goals. The next steps include exploring the correspondence of Mi Nino with mealtime behaviors observed through video recording

Supplier-origin mouse microbiomes significantly influence locomotor and anxiety-related behavior, body morphology, and metabolism.

The mouse is the most commonly used model species in biomedical research. Just as human physical and mental health are influenced by the commensal gut bacteria, mouse models of disease are influenced by the fecal microbiome (FM). The source of mice represents one of the strongest influences on the FM and can influence the phenotype of disease models. The FM influences behavior in mice leading to the hypothesis that mice of the same genetic background from different vendors, will have different behavioral phenotypes. To test this hypothesis, colonies of CD-1 mice, rederived via embryo transfer into surrogate dams from four different suppliers, were subjected to phenotyping assays assessing behavior and physiological parameters. Significant differences in behavior, growth rate, metabolism, and hematological parameters were observed. Collectively, these findings show the profound influence of supplier-origin FMs on host behavior and physiology in healthy, genetically similar, wild-type mice maintained in identical environments

Obesity Risk Assessment Tool for Low-Income Spanish Speaking Immigrant Parents with Young Children: Validity with BMI and Biomarkers of Obesity.

Children of Hispanic origin bear a high risk of obesity. Child weight gain trajectories are influenced by the family environment, including parent feeding practices. Excessive body fat can result in unhealthful metabolic and lipid profiles and increased risk of metabolic diseases. The objective was to estimate criterion validity of an obesity risk assessment tool targeting Spanish-speaking families of Mexican origin using anthropometric measures and blood values of their young children. A cross-sectional study design with five data collection sessions was conducted over an eight-week period and involved 206 parent/child dyads recruited at Head Start and the Special Supplemental Nutrition Program for Women, Infants and Children in Northern California. Main outcome measures were criterion validity of Niños Sanos, a pediatric obesity risk assessment tool, using anthropometric measures and blood biomarkers. Niños Sanos scores were inversely related to child BMI-for-age percentiles (p = 0.02), waist-for-height ratios (p = 0.05) and inversely related to blood biomarkers for the metabolic index (p = 0.03) and lipid index (p = 0.05) and positively related to anti-inflammatory index (p = 0.047). Overall, children with higher Niños Sanos scores had more healthful lipid, metabolic and inflammatory profiles, as well as lower BMI-for-age percentiles and waist-to height ratios, providing evidence for the criterion validity of the tool. Niños Sanos can be used by child obesity researchers, by counselors and medical professionals during clinic visits as a screening tool and by educators as a tool to set goals for behavior change

Obesity Risk Assessment Tool for Low-Income Spanish Speaking Immigrant Parents with Young Children: Validity with BMI and Biomarkers of Obesity.

Children of Hispanic origin bear a high risk of obesity. Child weight gain trajectories are influenced by the family environment, including parent feeding practices. Excessive body fat can result in unhealthful metabolic and lipid profiles and increased risk of metabolic diseases. The objective was to estimate criterion validity of an obesity risk assessment tool targeting Spanish-speaking families of Mexican origin using anthropometric measures and blood values of their young children. A cross-sectional study design with five data collection sessions was conducted over an eight-week period and involved 206 parent/child dyads recruited at Head Start and the Special Supplemental Nutrition Program for Women, Infants and Children in Northern California. Main outcome measures were criterion validity of Niños Sanos, a pediatric obesity risk assessment tool, using anthropometric measures and blood biomarkers. Niños Sanos scores were inversely related to child BMI-for-age percentiles (p = 0.02), waist-for-height ratios (p = 0.05) and inversely related to blood biomarkers for the metabolic index (p = 0.03) and lipid index (p = 0.05) and positively related to anti-inflammatory index (p = 0.047). Overall, children with higher Niños Sanos scores had more healthful lipid, metabolic and inflammatory profiles, as well as lower BMI-for-age percentiles and waist-to height ratios, providing evidence for the criterion validity of the tool. Niños Sanos can be used by child obesity researchers, by counselors and medical professionals during clinic visits as a screening tool and by educators as a tool to set goals for behavior change