Biology subjects

Pilarowski, G. O.

Publications and source records attributed to Pilarowski, G. O..

2 recordsLinked to original sources

bioRxiv2020

Leveraging the Mendelian Disorders of the Epigenetic Machinery to Systematically Map Functional Epigenetic Variation

The Mendelian Disorders of the Epigenetic Machinery (MDEMs) have emerged as a class of Mendelian disorders caused by loss-of-function variants in epigenetic regulators. Although each MDEM has a different causative gene, they exhibit several overlapping disease manifestations. Here, we hypothesize that this phenotypic convergence is a consequence of common abnormalities at the epigenomic level, which directly or indirectly lead to downstream convergence at the transcriptomic level. Therefore, we seek to identify abnormalities shared across multiple MDEMs, in order to pinpoint locations where epigenetic variation is causally related to disease phenotypes. To this end, we perform a comprehensive interrogation of chromatin (ATAC-Seq) and expression (RNA-Seq) states in B cells from mouse models of three MDEMs (Kabuki types 1&2 and Rubinstein-Taybi syndromes). We build on recent work in covariate-powered multiple testing to develop a new approach for the overlap analysis, which enables us to find extensive overlap primarily localized in gene promoters. We show that disruption of chromatin accessibility at promoters often leads to disruption of downstream gene expression, and identify 463 loci and 249 genes with shared disruption across all three MDEMs. As an example of how widespread dysregulation leads to specific phenotypes, we show that subtle expression alterations of multiple, IgA-relevant genes, collectively contribute to IgA deficiency in KS1 and RT1. In contrast, we predict that KS2 does not have IgA deficiency, and confirm this observation in vivo. We propose that the joint study of MDEMs offers a principled approach for systematically mapping functional epigenetic variation in mammals.

genetics↗

bioRxiv2020

Inhibition of KDM1A activity restores adult neurogenesis and improves hippocampal memory in a mouse model of Kabuki syndrome

Kabuki syndrome (KS) is a rare cause of intellectual disability primarily caused by loss of function mutations in lysine-specific methyltransferase 2D (KMT2D), which normally adds methyl marks to lysine 4 on histone 3. Previous studies have shown that a mouse model of KS (Kmt2d+/{beta}Geo) demonstrates disruption of adult neurogenesis and hippocampal memory. Proof-of-principle studies have shown postnatal rescue of neurological dysfunction following treatments that promote chromatin opening, however, these strategies are non-specific and do not directly address the primary defect of histone methylation. Since lysine-specific demethylase 1A (LSD1/KDM1A) normally removes the H3K4 methyl marks added by KMT2D, we hypothesize that inhibition of KDM1A demethylase activity may ameliorate molecular and phenotypic defects stemming from KMT2D loss. To test this hypothesis, we evaluated a recently developed KDM1A inhibitor (TAK-418) in Kmt2d+/{beta}Geo mice. We find that orally administered TAK-418 increases the numbers of newly born Doublecortin (DCX)+ cells and processes in hippocampus in a dose dependent manner. We also observe TAK-418-dependent rescue of histone modification defects in hippocampus both by Western blot and ChIP-Seq. Treatment rescues gene expression abnormalities including those of immediate early genes such as FBJ osteosarcoma oncogene (Fos) and FBJ osteosarcoma oncogene homolog B (Fosb). After 2 weeks of TAK-418, Kmt2d+/{beta}Geo mice demonstrate normalization of hippocampal memory defects. In summary, our data suggest that KDM1A inhibition is a plausible treatment strategy for KS and support the hypothesis that the epigenetic dysregulation secondary to KMT2D dysfunction plays a major role in the postnatal neurological disease phenotype in KS.

genetics↗