Autism NPCs from both idiopathic and CNV 16p11.2 deletion patients exhibit dysregulation of proliferation and mitogenic responses

Neural precursor cell (NPC) dysfunction has been consistently implicated in autism. Induced pluripotent stem cell (iPSC)-derived NPCs from two autism groups (three idiopathic [I-ASD] and two 16p11.2 deletion [16pDel]) were used to investigate if proliferation is commonly disrupted. All five individuals display defects, with all three macrocephalic individuals (two 16pDel, one I-ASD) exhibiting hyperproliferation and the other two I-ASD subjects displaying hypoproliferation. NPCs were challenged with bFGF, and all hyperproliferative NPCs displayed blunted responses, while responses were increased in hypoproliferative cells. mRNA expression studies suggest that different pathways can result in similar proliferation phenotypes. Since 16pDel deletes MAPK3, P-ERK was measured. P-ERK is decreased in hyperproliferative but increased in hypoproliferative NPCs. While these P-ERK changes are not responsible for the phenotypes, P-ERK and bFGF response are inversely correlated with the defects. Finally, we analyzed iPSCs and discovered that 16pDel displays hyperproliferation, while idiopathic iPSCs were normal. These data suggest that NPC proliferation defects are common in ASD.

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NPC proliferation defects are common in idiopathic and 16p11.2 CNV-deletion ASD

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All macrocephalic I-ASD and 16pDel individuals have hyperproliferative NPCs

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NPC proliferative responses to bFGF correlate inversely with P-ERK levels

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Both NPCs and IPSCs derived from 16pDel individuals exhibit hyperproliferation

Childhood maltreatment, serotonin transporter gene, and risk for callous and unemotional traits: A prospective investigation

Previous studies have reported associations between the serotonin transporter 5-HTTLPR genotype and antisocial and aggressive traits and between child maltreatment and antisocial traits. However, few studies have examined whether 5-HTTLPR moderates the influence of childhood maltreatment on callous and unemotional traits, a hallmark of psychopathy. Using a prospective cohort design, children with documented cases of maltreatment and matched controls were followed up and interviewed in adulthood. DNA was extracted from blood and saliva (N = 414) and callous-unemotional (CU) traits were assessed. Childhood maltreatment predicted higher CU scores in adulthood, whereas the effect of 5-HTTLPR was not significant. The effect of child maltreatment on CU traits did not differ by genetic risk (high or low activity 5-HTTLPR), whereas controls with the LL genotype had higher CU scores than controls with the SS genotype. Similar results were found for females and White, non-Hispanics, but not for males and Blacks. Variations in 5-HTTLPR did not affect the impact of child maltreatment on CU traits in adulthood. Genetic risk had a stronger effect on adults with lower environmental risk (controls). Having a history of child maltreatment or the LL genotype placed participants at risk for higher levels of callous and unemotional trait scores.

Social (Pragmatic) Communication Disorder: Another name for the Broad Autism Phenotype?

The Diagnostic and Statistical Manual of Mental Disorders' (5th ed.) Social (Pragmatic) Communication Disorder is meant to capture the social elements of communication dysfunction in children who do not meet autism spectrum disorder criteria. It is unclear whether Social (Pragmatic) Communication Disorder captures these elements without overlapping with Autism Spectrum Disorder or the Diagnostic and Statistical Manual of Mental Disorders' (5th ed.) Language Disorder. Standardized behavioral assessments administered during a family genetics study were used to evaluate the social communication impairment and the restricted interests and repetitive behaviors in persons with autism spectrum disorder, language impairment, or neither. Social communication impairment and restricted interests and repetitive behavior were significantly correlated in all family members regardless of affection status. Rates of social communication impairment and restricted interests and repetitive behavior were highest in individuals with autism spectrum disorder. One-third of family members with language impairment presented with at least mild/moderate levels of social communication impairment (36.6%) and restricted interests and repetitive behavior (43.3%). A subset of unaffected members also presented with mild/moderate levels of social communication impairment (parents = 10.1%, siblings 11.6%) and restricted interests and repetitive behavior (parents = 14.0%, siblings = 22.1%). The majority of child family members with mild/moderate levels of social communication impairment had similar restricted interest and repetitive behavior levels reflecting criteria representing the Broad Autism Phenotype. These data suggest that social pragmatic communication disorder does not capture the profiles of children who have both social communication impairment and restricted interests and repetitive behavior but are in need of clinical services.

Validation of a microRNA target site polymorphism in H3F3B that is potentially associated with a broad schizophrenia phenotype

Despite much progress, few genetic findings for schizophrenia have been assessed by functional validation experiments at the molecular level. We previously reported evidence for genetic linkage of broadly defined schizophrenia to chromosome 17q25 in a sample of 24 multiplex families. 2,002 SNPs under this linkage peak were analyzed for evidence of linkage disequilibrium using the posterior probability of linkage (PPL) framework. SNP rs1060120 produced the strongest evidence for association, with a PPLD|L score of 0.21. This SNP is located within the 3'UTR of the histone gene H3F3B and colocalizes with potential gene target miR-616. A custom miRNA target prediction program predicted that the binding of miR-616 to H3F3B transcripts would be altered by the allelic variants of rs1060120. We used dual luciferase assays to experimentally validate this interaction. The rs1060120 A allele significantly reduced luciferase expression, indicating a stronger interaction with miR-616 than the G allele (p = 0.000412). These results provide functional validation that this SNP could alter schizophrenia epigenetic mechanisms thereby contributing to schizophrenia-related disease risk.

Rapid Detection of Neurodevelopmental Phenotypes in Human Neural Precursor Cells (NPCs)

Human brain development proceeds through a series of precisely orchestrated processes, with earlier stages distinguished by proliferation, migration, and neurite outgrowth; and later stages characterized by axon/dendrite outgrowth and synapse formation. In neurodevelopmental disorders, often one or more of these processes are disrupted, leading to abnormalities in brain formation and function. With the advent of human induced pluripotent stem cell (hiPSC) technology, researchers now have an abundant supply of human cells that can be differentiated into virtually any cell type, including neurons. These cells can be used to study both normal brain development and disease pathogenesis. A number of protocols using hiPSCs to model neuropsychiatric disease use terminally differentiated neurons or use 3D culture systems termed organoids. While these methods have proven invaluable in studying human disease pathogenesis, there are some drawbacks. Differentiation of hiPSCs into neurons and generation of organoids are lengthy and costly processes that can impact the number of experiments and variables that can be assessed. In addition, while post-mitotic neurons and organoids allow the study of disease-related processes, including dendrite outgrowth and synaptogenesis, they preclude the study of earlier processes like proliferation and migration. In neurodevelopmental disorders, such as autism, abundant genetic and post-mortem evidence indicates defects in early developmental processes. Neural precursor cells (NPCs), a highly proliferative cell population, may be a suitable model in which to ask questions about ontogenetic processes and disease initiation. We now extend methodologies learned from studying development in mouse and rat cortical cultures to human NPCs. The use of NPCs allows us to investigate disease-related phenotypes and define how different variables (e.g., growth factors, drugs) impact developmental processes including proliferation, migration, and differentiation in only a few days. Ultimately, this toolset can be used in a reproducible and high-throughput manner to identify disease-specific mechanisms and phenotypes in neurodevelopmental disorders.

Childhood maltreatment predicts allostatic load in adulthood

Childhood maltreatment has been linked to numerous negative health outcomes. However, few studies have examined mediating processes using longitudinal designs or objectively measured biological data. This study sought to determine whether child abuse and neglect predicts allostatic load (a composite indicator of accumulated stress-induced biological risk) and to examine potential mediators. Using a prospective cohort design, children (ages 0-11) with documented cases of abuse and neglect were matched with non-maltreated children and followed up into adulthood with in-person interviews and a medical status exam (mean age 41). Allostatic load was assessed with nine physical health indicators. Child abuse and neglect predicted allostatic load, controlling for age, sex, and race. The direct effect of child abuse and neglect persisted despite the introduction of potential mediators of internalizing and externalizing problems in adolescence and social support and risky lifestyle in middle adulthood. These findings reveal the long-term impact of childhood abuse and neglect on physical health over 30 years later.

Improvements to bead-based oligonucleotide ligation SNP genotyping assays

We describe a bead-based, multiplexed, oligonucleotide ligation assay (OLA) performed on the Luminex flow cytometer. Differences between this method and those previously reported include the use of far fewer beads and the use of a universal oligonucleotide for signal detection. These innovations serve to significantly reduce the cost of the assay, while maintaining robustness and accuracy. Comparisons are made between the Luminex OLA and both pyrosequencing and direct sequencing. Experiments to assess conversion rates, call rates, and concordance across technical replicates are also presented.

Schizophrenia and genetics: new insights

There is consistent evidence that the principal etiology of schizophrenia involves predisposing genetic factors. Recent years have seen several new insights in the genetics of schizophrenia. Several chromosomal regions show significant evidence that they contain schizophrenia susceptibility genes. A clinically relevant genetic subtype of schizophrenia (22q deletion syndrome) has been identified. There is new evidence that spontaneous mutations may play a role. There are new recommendations for genetic counseling. The progress to date suggests that understanding of a neurodevelopmental pathway from genetic susceptibility to schizophrenia will soon be fundamentally altered by molecular genetic advances in this complex disease.

Genetic insights into schizophrenia

OBJECTIVE

To outline new insights into the genetic etiology of schizophrenia.

METHODS

We discuss several commonly held beliefs about the genetic issues in schizophrenia.

RESULTS

The complex genetic nature of the illness poses a challenge for investigators seeking causative genetic mutations. Multiple independent research findings are, however converging to identify a relatively small number of chromosomal locations that appear to contain schizophrenia susceptibility genes. Also, a clinically relevant genetic subtype of schizophrenia (22qDS) has been identified. We are developing a better understanding of how schizophrenia relates to other psychiatric disorders. While investigations into the possible roles of dopaminergic and serotonergic systems continue, other approaches that do not require theories of the mechanism of illness are also being used to identify candidate susceptibility genes.

CONCLUSIONS

Research to date suggests that our understanding of the pathophysiology of schizophrenia will soon be fundamentally altered by genetic approaches to this complex disease.

Genetic counselling for schizophrenia in the era of molecular genetics

OBJECTIVE

To review the role of genetic counselling for individuals with psychiatric illnesses.

METHOD

Using schizophrenia as an example and including updated information about a genetic subtype (22q deletion syndrome), we discuss the value of the genetic counselling process in psychiatry, with support from the literature and our clinical experience.

RESULTS

Genetic counselling, the process through which knowledge about the genetics of illnesses is shared, provides information on the inheritance of illnesses and their recurrence risks; addresses the concerns of patients, their families, and their health care providers; and supports patients and their families dealing with these illnesses. For comprehensive medical management, this service should be available to all individuals with schizophrenia and their families.

CONCLUSIONS

New findings in the genetics of psychiatric illness may have important clinical implications for patients and their families.

Report of a workshop on genetic linkage studies in schizophrenia

A workshop on genetic linkage studies in schizophrenia was held at Columbia University's Arden House Conference Center in October 1989. This report summarizes the contents of invited talks by Drs. Arno Motulsky and T. Conrad Gilliam and the discussions at the five workshop sessions. Topics of the workshop sessions were (1) diagnostic boundaries and hierarchies in schizophrenia, (2) genetic models and linkage parameters, (3) selection and ascertainment of pedigrees, (4) future extensions of molecular genetics strategies, and (5) possibilities for future collaboration.

Bacteriophage SPO1 genes 33 and 34. Location and primary structure of genes encoding regulatory subunits of Bacillus subtilis RNA polymerase

Bacteriophage SPO1 gene 33 and 34 products are required for SPO1 late gene transcription. Both proteins bind to the core RNA polymerase of the Bacillus subtilis host to direct the recognition of SPO1 late gene promoters, whose sequences differ from those of SPO1 early and middle gene promoters. We have located and cloned the genes for these two regulatory proteins, and have engineered their expression in Escherichia coli by placing them under the control of the bacteriophage lambda PL promoter. Nucleotide sequence analysis indicated that genes 33 and 34 overlap by 4 base-pairs and encode highly charged, slightly basic proteins of molecular weight 11,902 and 23,677, respectively.

Bacteriophage SPO1 gene 27: location and nucleotide sequence

Bacteriophage SPO1 gene 27, whose product is required for late gene transcription and DNA replication, has been cloned in Escherichia coli, and its complete nucleotide sequence has been determined. We infer that the product of gene 27 is a highly basic 17,518-dalton protein of 155 amino acids. The gene for this regulatory protein is transcribed from two promoters: an early promoter situated before the adjacent upstream gene 28 and a middle promoter located between genes 28 and 27.