Novel heterochronic functions of the Caenorhabditis elegans period-related protein LIN-42

AbstractLIN-42, the Caenorhabditis elegans homolog of the Period (Per) family of circadian rhythm proteins, functions as a member of the heterochronic pathway, regulating temporal cell identities. We demonstrate that lin-42 acts broadly, timing developmental events in the gonad, vulva, and sex myoblasts, in addition to its well-established role in timing terminal differentiation of the hypodermis. In the vulva, sex myoblasts, and hypodermis, lin-42 activity prevents stage-specific cell division patterns from occurring too early. This general function of timing stage-appropriate cell division patterns is shared by the majority of heterochronic genes; their mutation temporally alters stage-specific division patterns. In contrast, lin-42 function in timing gonad morphogenesis is unique among the known heterochronic genes: inactivation of lin-42 causes the elongating gonad arms to reflex too early, a phenotype which implicates lin-42 in temporal regulation of cell migration. Three additional isoforms of lin-42 are identified that expand our view of the lin-42 locus and significantly extend the homology between LIN-42 and other PER family members. We show that, similar to PER proteins, LIN-42 has a dynamic expression pattern; its levels oscillate relative to the molts during postembryonic development. Transformation rescue studies indicate lin-42 is bipartite with respect to function. Intriguingly, the hallmark PAS domain is dispensable for LIN-42 function in transgenic animals

Pre- and Postnatal Fine Particulate Matter Exposure and Childhood Cognitive and Adaptive Function

Increasing evidence exists for an association between early life fine particulate matter (PM2.5) exposure and several neurodevelopmental outcomes, including autism spectrum disorder (ASD); however, the association between PM2.5 and adaptive and cognitive function remains poorly understood. Participants included 658 children with ASD, 771 with a non-ASD developmental disorder, and 849 population controls from the Study to Explore Early Development. Adaptive functioning was assessed in ASD cases using the Vineland Adaptive Behavior Scales (VABS); cognitive functioning was assessed in all groups using the Mullen Scales of Early Learning (MSEL). A satellite-based model was used to assign PM2.5 exposure averages during pregnancy, each trimester, and the first year of life. Linear regression was used to estimate beta coefficients and 95% confidence intervals, adjusting for maternal age, education, prenatal tobacco use, race-ethnicity, study site, and season of birth. PM2.5 exposure was associated with poorer VABS scores for several domains, including daily living skills and socialization. Associations were present between prenatal PM2.5 and lower MSEL scores for all groups combined; results were most prominent for population controls in stratified analyses. These data suggest that early life PM2.5 exposure is associated with specific aspects of cognitive and adaptive functioning in children with and without ASD

Air Pollution Exposure during Pregnancy and Childhood Autistic Traits in Four European Population-Based Cohort Studies: The ESCAPE Project

Background: Prenatal exposure to air pollutants has been suggested as a possible etiologic factor for the occurrence of autism spectrum disorder. Objectives: We aimed to assess whether prenatal air pollution exposure is associated with childhood autistic traits in the general population. Methods: Ours was a collaborative study of four European population-based birth/child cohorts—CATSS (Sweden), Generation R (the Netherlands), GASPII (Italy), and INMA (Spain). Nitrogen oxides (NO2, NOx) and particulate matter (PM) with diameters of ≤ 2.5 μm (PM2.5), ≤ 10 μm (PM10), and between 2.5 and 10 μm (PMcoarse), and PM2.5 absorbance were estimated for birth addresses by land-use regression models based on monitoring campaigns performed between 2008 and 2011. Levels were extrapolated back in time to exact pregnancy periods. We quantitatively assessed autistic traits when the child was between 4 and 10 years of age. Children were classified with autistic traits within the borderline/clinical range and within the clinical range using validated cut-offs. Adjusted cohort-specific effect estimates were combined using random-effects meta-analysis. Results: A total of 8,079 children were included. Prenatal air pollution exposure was not associated with autistic traits within the borderline/clinical range (odds ratio = 0.94; 95% CI: 0.81, 1.10 per each 10-μg/m3 increase in NO2 pregnancy levels). Similar results were observed in the different cohorts, for the other pollutants, and in assessments of children with autistic traits within the clinical range or children with autistic traits as a quantitative score. Conclusions: Prenatal exposure to NO2 and PM was not associated with autistic traits in children from 4 to 10 years of age in four European population-based birth/child cohort studies.Funding was provided as follows: ESCAPE Project— European Community’s Seventh Framework Program (FP7/2007-2011-GA#211250). CATSS, Sweden— Swedish Research Council for Health, Working Life and Welfare (FORTE), Swedish Research Council (VR) Formas, in partner hip with FORTE and VINNOVA (cross-disciplinary research program concerning children’s and young people’s mental health); VR through the Swedish Initiative for Research on Microdata in the Social And Medical Sciences (SIMSAM) framework grant 340-2013-5867; HKH Kronprinsessan Lovisas förening för barnasjukvård; and the Strategic Research Program in Epidemiology at Karolinska Institutet. Generation R, the Netherlands—The Generation R Study is conducted by the Erasmus University Medical Center in close collaboration with the School of Law and Faculty of Social Sciences of the Erasmus University Rotterdam; the Municipal Health Service Rotterdam area, Rotterdam; the Rotterdam Homecare foundation, Rotterdam; and the Stichting Trombosedienst & Artsenlaboratorium Rijnmond (STAR-MDC), Rotterdam. The general design of the Generation R Study is made possible by financial support from the Erasmus University Medical Center, Rotterdam; the Erasmus University Rotterdam; the Netherlands Organization for Health Research and Development (ZonMw); the Netherlands Organization for Scientific Research (NWO); and the Ministry of Health, Welfare and Sport. The Netherlands Organisation for Applied Scientific Research (TNO) received funding from the Netherlands Ministry of Infrastructure and the Environment to support exposure assessment. GASPII, Italy—grant from the Italian Ministry of Health (ex art.12, 2001). INMA, Spain— grants from Instituto de Salud Carlos III (Red INMA G03/176 and CB06/02/0041 FIS-FEDER 03/1615, 04/1509, 04/1112, 04/1931, 05/1079, 05/1052, 06/1213, 07/0314, 09/02647, 11/01007, 11/02591, CP11/00178, FIS-PI041436, FIS-PI081151, FIS-PI06/0867, FIS-PS09/00090), PI13/1944, PI13_02032, PI14/0891, PI14/1687, MS13/00054, UE (FP7-ENV-2011 cod 282957, and HEALTH.2010.2.4.5-1); Generalitat de Catalunya-CIRIT 1999SGR 00241; La Fundació La Marató de TV3 (090430); Conselleria de Sanitat Generalitat Valenciana; Department of Health of the Basque Government (2005111093 and 2009111069); and Provincial Government of Gipuzkoa (DFG06/004 and DFG08/001). V.W.V.J. received an additional grant from the Netherlands Organization for Health Research and Development (ZonMw 90700303, 916.10159). A.G.’s work was supported by a research grant from the European Community’s 7th Framework Programme (FP7/2008–2013-GA#212652). A full roster of the INMA project investigators can be found online (http://www. proyectoinma.org/presentacion-inma/listado-investigadores/ en_listado-investigadores.html)