Biology subjects

Cambiasso, M. J.

Publications and source records attributed to Cambiasso, M. J..

2 recordsLinked to original sources

bioRxiv2022

Epigenetic Modifier Kdm6a/Utx Controls the Specification of Hypothalamic Neuronal Subtypes in a Sex-Dependent Manner

Kdm6a is an X chromosome-linked H3K27me2/3 demethylase that promotes chromatin accessibility and gene transcription and is critical for tissue/cell-specific differentiation. Previous results showed higher Kdm6a levels in XX than in XY hypothalamic neurons and a female-specific requirement for Kdm6a in mediating increased axogenesis before brain masculinization. Here we explored the sex-specific role of Kdm6a in the specification of neuronal subtypes in the developing hypothalamus. Hypothalamic neuronal cultures were established from sex-segregated E14 mouse embryos and transfected with siRNAs to knockdown Kdm6a expression (Kdm6a-KD). We evaluated by immunofluorescence the effect of Kdm6a-KD on Ngn3, a bHLH transcription factor regulating neuronal sub-specification in hypothalamus. Kdm6a-KD decreased Ngn3 expression in females but not in males, abolishing basal sex differences. Then, we analyzed Kdm6a-KD effect on Ascl1, Pomc, Npy, Sf1, Gad1 and Th expression by RT-qPCR. While Kdm6a-KD downregulated Ascl1 in both sexes equally, we found sex-specific results for Pomc, Npy and Th. Pomc and Th expressed higher in female than in male neurons and Kdm6a-KD reduced their levels only in females, while Npy expressed higher in male than in female neurons and Kdm6a-KD upregulated its expression only in females. Identical results were found by immunofluorescence for Pomc and Npy neuropeptides. Finally, using ChIP-qPCR we found higher H3K27me3 levels at Ngn3, Pomc and Npy promoters in male neurons, in line with Kdm6a higher expression and demethylase activity in females. These results indicate that Kdm6a plays a key sex-specific role in controlling the differentiation of neuronal populations regulating food intake and energy homeostasis.

neuroscience↗

bioRxiv2021

X-Linked Histone H3K27 Demethylase Kdm6a Regulates Sexually Dimorphic Differentiation of Hypothalamic Neurons

Several X-linked genes are involved in neuronal differentiation and may contribute to the generation of sex dimorphisms in brain. Previous results showed that XX hypothalamic neurons grow faster, have longer axons, and exhibit higher expression of the neuritogenic gene neurogenin 3 (Ngn3) than XY before perinatal masculinization. Here we evaluated the participation of candidate X-linked genes in the development of these sex differences, focusing mainly on Kdm6a, a gene encoding for an H3K27 demethylase with functions controlling gene expression genome-wide. We established hypothalamic neuronal cultures from wild-type or transgenic Four Core Genotypes mice, a model that allows evaluating the effect of sex chromosomes independently of gonadal type. X-linked genes Kdm6a, Eif2s3x and Ddx3x showed higher expression in XX compared to XY neurons, regardless of gonadal sex. Moreover, Kdm6a expression pattern with higher mRNA levels in XX than XY did not change with age at E14, P0, and P60 in hypothalamus or under 17{beta}-estradiol treatment in culture. Kdm6a pharmacological blockade by GSK-J4 reduced the expression of neuritogenic genes Neurod1, Neurod2 and Cdk5r1 in both sexes equally, while a sex-specific effect was observed on Ngn3 levels, with a decrease in XX and an increase in XY neurons. Finally, both Kdm6a inhibition and its downregulation using siRNA reduced axonal length only in female neurons, abolishing the sex differences observed in control conditions. Altogether, these results point to Kdm6a as a key mediator of the higher axogenesis and Ngn3 expression observed in XX neurons before critical period of brain masculinization.

neuroscience↗