The histone H3-lysine 4-methyltransferase Mll4 regulates the development of growth hormone-releasing hormone-producing neurons in the mouse hypothalamus

In humans, inactivating mutations in MLL4, which encodes a histone H3-lysine 4-methyltransferase, lead to Kabuki syndrome (KS). While dwarfism is a cardinal feature of KS, the underlying etiology remains unclear. Here we report that Mll4 regulates the development of growth hormone-releasing hormone (GHRH)-producing neurons in the mouse hypothalamus. Our two Mll4 mutant mouse models exhibit dwarfism phenotype and impairment of the developmental programs for GHRH-neurons. Our ChIP-seq analysis reveals that, in the developing mouse hypothalamus, Mll4 interacts with the transcription factor Nrf1 to trigger the expression of GHRH-neuronal genes. Interestingly, the deficiency of Mll4 results in a marked reduction of histone marks of active transcription, while treatment with the histone deacetylase inhibitor AR-42 rescues the histone mark signature and restores GHRH-neuronal production in Mll4 mutant mice. Our results suggest that the developmental dysregulation of Mll4-directed epigenetic control of transcription plays a role in the development of GHRH-neurons and dwarfism phenotype in mice.

Single cell transcriptome analysis of developing arcuate nucleus neurons uncovers their key developmental regulators

Despite the crucial physiological processes governed by neurons in the hypothalamic arcuate nucleus (ARC), such as growth, reproduction and energy homeostasis, the developmental pathways and regulators for ARC neurons remain understudied. Our single cell RNA-seq analyses of mouse embryonic ARC revealed many cell type-specific markers for developing ARC neurons. These markers include transcription factors whose expression is enriched in specific neuronal types and often depleted in other closely-related neuronal types, raising the possibility that these transcription factors play important roles in the fate commitment or differentiation of specific ARC neuronal types. We validated this idea with the two transcription factors, Foxp2 enriched for Ghrh-neurons and Sox14 enriched for Kisspeptin-neurons, using Foxp2- and Sox14-deficient mouse models. Taken together, our single cell transcriptome analyses for the developing ARC uncovered a panel of transcription factors that are likely to form a gene regulatory network to orchestrate fate specification and differentiation of ARC neurons.

Common misconceptions in people with epilepsy

Background and Purpose

This study was undertaken to determine the knowledge that people with epilepsy (PWE) have regarding the nature of epilepsy and its management, and also to identify the factors contributing to their knowledge of epilepsy.

Methods

We studied 79 consecutive PWE who visited the outpatient clinic of Seoul National University Hospital using a structured questionnaire consisting of 27 questions in 3 categories. The mean correct response rate was 61%, with 81% believing that brain cells die during a seizure, 29% considering it dangerous to take a bath or shower alone, and more than 70% believing that taking antiepileptic drugs (AEDs) will impair memory and damage the liver and kidneys.

Results

The mean overall correct-answer rate was significantly related to gender, length of education, type of seizures, and regularity of hospital visits (all p<0.05).

Conclusions

The level of knowledge deviated significantly from the scientific data, especially in the causes of epilepsy, safety issues, and side effects of AEDs. A large-scale study should identify those PWE with the lowest knowledge of epilepsy, and then develop and implement suitable educational intervention programs to improve their knowledge.