Sexually Dimorphic Alterations in the Transcriptome and Behavior with Loss of Histone Demethylase KDM5C

Chromatin dysregulation has emerged as a major hallmark of neurodevelopmental disorders such as intellectual disability (ID) and autism spectrum disorders (ASD). The prevalence of ID and ASD is higher in males compared to females, with unknown mechanisms. Intellectual developmental disorder, X-linked syndromic, Claes-Jensen type (MRXSCJ), is caused by loss-of-function mutations of lysine demethylase 5C (KDM5C), a histone H3K4 demethylase gene. KDM5C escapes X-inactivation, thereby presenting at a higher level in females. Initially, MRXSCJ was exclusively reported in males, while it is increasingly evident that females with heterozygous KDM5C mutations can show cognitive deficits. The mouse model of MRXSCJ, male Kdm5c-hemizygous knockout animals, recapitulates key features of human male patients. However, the behavioral and molecular traits of Kdm5c-heterozygous female mice remain incompletely characterized. Here, we report that gene expression and behavioral abnormalities are readily detectable in Kdm5c-heterozygous female mice, demonstrating the requirement for a higher KDM5C dose in females. Furthermore, we found both shared and sex-specific consequences of a reduced KDM5C dose in social behavior, gene expression, and genetic interaction with the counteracting enzyme KMT2A. These observations provide an essential insight into the sex-biased manifestation of neurodevelopmental disorders and sex chromosome evolution.

Small molecule mediated stabilization of PP2A modulates the Homologous Recombination pathway and potentiates DNA damage-induced cell death

High-Grade Serous Carcinoma (HGSC) is the most common and lethal ovarian cancer subtype. PARP-inhibitors (PARPi) have become the mainstay of HGSC targeted therapy, given that these tumors are driven by a high degree of genomic instability and Homologous Recombination (HR) defects. Nonetheless, ~30% of patients initially respond to treatment, ultimately relapsing with resistant disease. Thus, despite recent advances in drug development and an increased understanding of genetic alterations driving HGSC progression, mortality has not declined, highlighting the need for novel therapies. Using a Small Molecule Activator of Protein Phosphatase 2A (PP2A) (SMAP-061), we investigated the mechanism by which PP2A stabilization induces apoptosis in Patient-Derived HGSC cells and Xenograft (PDX) models alone or in combination with PARPi. We uncovered that PP2A genes essential for cellular transformation (B56,B56 and PR72) and basal phosphatase activity (PP2A-A and -C) are heterozygously lost in the majority of HGSC. Moreover, loss of these PP2A genes correlate with worse overall patient survival. We show that SMAP-061 stabilization of PP2A inhibits the homologous recombination (HR) output by targeting RAD51, leading to chronic accumulation of DNA damage and ultimately apoptosis. Furthermore, combination of SMAP-061 and PARPi leads to enhanced apoptosis in both HR-proficient and HR-deficient cells and in PDX models. Our studies identifies PP2A as a novel regulator of HR and indicates PP2A modulators as a therapeutic therapy for HGSC. In sum, our findings further emphasize the potential of PP2A modulators to overcome PARPi insensitivity, given that targeting RAD51 presents benefits in overcoming PARPi-resistance driven by BRCA1/2 mutation reversions.

Mutually suppressive roles of KMT2A and KDM5C in behaviour, neuronal structure, and histone H3K4 methylation

Histone H3 lysine 4 methylation (H3K4me) is extensively regulated by numerous writer and eraser enzymes in mammals. Nine H3K4me enzymes are associated with neurodevelopmental disorders to date, indicating their important roles in the brain. However, interplay among H3K4me enzymes during brain development remains largely unknown. Here, we show functional interactions of a writer-eraser duo, KMT2A and KDM5C, which are responsible for Wiedemann-Steiner Syndrome (WDSTS), and mental retardation X-linked syndromic Claes-Jensen type (MRXSCJ), respectively. Despite opposite enzymatic activities, the two mouse models deficient for either Kmt2a or Kdm5c shared reduced dendritic spines and increased aggression. Double mutation of Kmt2a and Kdm5c clearly reversed dendritic morphology, key behavioral traits including aggression, and partially corrected altered transcriptomes and H3K4me landscapes. Thus, our study uncovers common yet mutually suppressive aspects of the WDSTS and MRXSCJ models and provides a proof of principle for balancing a single writer-eraser pair to ameliorate their associated disorders.

Intervention to improve physician documentation and knowledge of child sexual abuse: a randomized, controlled trial

OBJECTIVE

To determine if written feedback improves the chart documentation and knowledge of physicians doing evaluations for child sexual abuse and to learn what other factors are associated with better documentation and knowledge.

DESIGN

Randomized, controlled trial.

SETTING

A statewide network of physicians performing child abuse evaluations.

PARTICIPANTS

All physicians who performed evaluations for sexual abuse during 1991 to 1992. One hundred forty-seven physicians were randomized to control (n = 75) and intervention (n = 72) groups, 122 (83%) remained at follow-up, and 87 of the 122 (71%) had done evaluations for child sexual abuse.

INTERVENTIONS

Tailored written feedback based on chart reviews and relevant articles were sent to a randomly selected one-half of the physicians during a 3-month period.

MAIN OUTCOME MEASURES

The quality of documentation and physician knowledge before and after the intervention.

RESULTS

Documentation by chart review of up to five randomly chosen records per physician (preintervention, n = 552; postintervention, n = 259) by reviewers blinded to intervention status and physician knowledge was assessed by survey (78% completion). Change in documentation and knowledge for physicians in the intervention group was not statistically significant compared with the control group. The risk ratio for a mean overall history rating of excellent/good was 0.89 (0.63, 1.25) and for a mean overall physical examination rating of excellent/good was 1.03 (0.73, 1.45). Both groups improved significantly during the time period. The largest improvements in the time period were in documenting the history of where abuse occurred, in the physical examination position, hymenal description, penile findings, and knowing that chlamydia infection should be assessed by culture. A structured medical record, female physicians, and credits in continuing medical education were associated with better documentation.

CONCLUSIONS

Tailored feedback to the physician with directed educational materials did not seem to improve most aspects of documentation and knowledge of child sexual abuse, although notable improvement was seen during the time period studied. This study suggests that chart audits may not be the best use of resources for trying to improve physician behavior; credits in continuing medical education and use of structured records may be more likely to be beneficial.

On the use of a logistic risk score in predicting risk of coronary heart disease

Many studies over the last 20 years have used logistic regression to model the relationship between the risk of developing coronary heart disease (CHD) and the levels of risk factors such as high blood pressure, high serum cholesterol, and cigarette smoking. Subsequently, several investigators have proposed the use of some of the published estimated logistic risk functions to predict risk in new populations. Because of great variation in definition of event, duration of follow-up, population characteristics, definition of risk variables, and selection of other variables in the logistic functions, direct use of such established functions would generally not have validity for the prediction of absolute risk levels. A review of fifteen of these studies indicates on the one hand generally similar results in direction and order of magnitude of effects of the major risk factors, confirming the importance of these risk factors of CHD. On the other hand the reviews indicate sufficient variation to suggest that extrapolation to new populations even to predict relative risk is not justified.

An outbreak of disease in pigeons associated with a herpesvirus

An outbreak of disease in young pigeons associated with a herpesvirus is reported. The clinical history, macroscopic and microscopic appearance of lesions and virus isolation are described. Most affected birds showed lesions in the upper alimentary tract epithelium as well as in skin, nasal mucosa and salivary glands. Lesions in liver, spleen and pancreas were uncommon. A herpesvirus capable of producing CPE on tissue culture and lesions on chorioallantoic membrane of developing chicken embryos was isolated and described. Inoculation of experimental pigeons with the virus failed to reproduce the disease.