Rett syndrome (RTT), caused by mutation of the DNA binding protein MECP2, is one of the most common causes for mental retardation in females. Both loss of function mutations of the gene as well as overexpression such as seen in the MECP2 duplication gain of function syndrome, lead to RTT-like syndrome indicating that increased MECP2 levels can be equally detrimental to the nervous system as MECP2 deficiency. While it has been well established that MECP2 deficiency causes RTT in a cell autonomous manner, recent evidence points to an additional cell-non-autonomous mechanism based on therapeutic effects of MECP2 expression in astrocytes or on transplantation with wild type microglia. These observations as well as the recognition that re- expression of MECP2 or treatment with small molecules can halt disease progression and can even revert symptoms in the adult Rett mouse suggest that MECP2 is required for the maintenance of neuronal function. While these results are exciting and suggest a rational treatment in humans, it is crucial to assess therapeutic strategies in well-defined experimental systems using human cells as readout. This project seeks to set up a platform that utilizes human RTT neurons for clarifying the roles of MECP2 in gene expression and that permits the evaluation of candidate treatments in culture as well as under in vivo conditions. Using human iPS cell- derived neuronal cultures, the initial goal is to establish an experimental paradigm that allows defining the molecular role o MECP2 in gene regulation and to provide a robust and quantifiable disease-relevant phenotypic readout in human mutant neurons. We will use molecular approaches such as CHIP-seq to map binding sites of MECP2 to 5mC and 5hmC modified genomic sites and dissect the modes of gene activation and repression. Furthermore, we will identify target genes of MECP2 and MECP2- interacting partners and clarify the deregulation of MECP2 target genes in loss and gain of function RTT. A major focus of the proposal is to establish a platform that allows assessing the efficacy of therapeutic strategies to reverse the RTT phenotype of human neurons under in vitro and in vivo conditions. (i) To overcome limitations of conventional neural 2D culture systems we will use RTT ES or iPS cells as starting point to generate human cerebral organoid cultures. This will enable the analysis of cell-cell interactions and of potentia therapeutic agents in a well-defined 3D test system. (ii) We will transplant GFP-marked neuronal precursors into the developing mouse brain to generate animals that carry human MECP2 mutant neurons incorporated into their brain. By allowing the human neurons to integrate into the intact mouse brain, we seek to establish a clinically relevant platform to perform in vivo validation of growth factors and small molecule compounds that could be beneficial for the treatment of RTT patients.

Public Health Relevance

Rett syndrome (RTT), caused by mutation of the DNA binding protein MECP2, is one of the most common causes for mental retardation in females. Of great interest is the insight that disease progression can be halted or even be reversed in adult mice by reactivation of Mecp2 or by treatment with small molecules. This project seeks to set up a platform that uses human iPS or ES cell-derived neurons for clarifying the molecular roles of MECP2 in gene expression and to allow the evaluation of candidate treatments in culture as well as under in vivo conditions in mice transplanted with human RTT neurons into the brain.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Project (R01)
Project #
2R01MH104610-15
Application #
8760558
Study Section
Developmental Brain Disorders Study Section (DBD)
Program Officer
Panchision, David M
Project Start
2014-09-15
Project End
2019-07-31
Budget Start
2014-09-15
Budget End
2015-07-31
Support Year
15
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Whitehead Institute for Biomedical Research
Department
Type
DUNS #
City
Cambridge
State
MA
Country
United States
Zip Code
02142
Roessler, Reinhard; Goldmann, Johanna; Shivalila, Chikdu et al. (2018) JIP2 haploinsufficiency contributes to neurodevelopmental abnormalities in human pluripotent stem cell-derived neural progenitors and cortical neurons. Life Sci Alliance 1:e201800094
Ma, Haiting; Wert, Katherine J; Shvartsman, Dmitry et al. (2018) Establishment of human pluripotent stem cell-derived pancreatic ?-like cells in the mouse pancreas. Proc Natl Acad Sci U S A 115:3924-3929
Cohen, Malkiel A; Markoulaki, Styliani; Jaenisch, Rudolf (2018) Matched Developmental Timing of Donor Cells with the Host Is Crucial for Chimera Formation. Stem Cell Reports 10:1445-1452
Mellios, N; Feldman, D A; Sheridan, S D et al. (2018) MeCP2-regulated miRNAs control early human neurogenesis through differential effects on ERK and AKT signaling. Mol Psychiatry 23:1051-1065
Sahakyan, Anna; Kim, Rachel; Chronis, Constantinos et al. (2017) Human Naive Pluripotent Stem Cells Model X Chromosome Dampening and X Inactivation. Cell Stem Cell 20:87-101
Weintraub, Abraham S; Li, Charles H; Zamudio, Alicia V et al. (2017) YY1 Is a Structural Regulator of Enhancer-Promoter Loops. Cell 171:1573-1588.e28
Soldner, Frank; Stelzer, Yonatan; Shivalila, Chikdu S et al. (2016) Parkinson-associated risk variant in distal enhancer of ?-synuclein modulates target gene expression. Nature 533:95-9
Hockemeyer, Dirk; Jaenisch, Rudolf (2016) Induced Pluripotent Stem Cells Meet Genome Editing. Cell Stem Cell 18:573-86
Banerjee, Abhishek; Rikhye, Rajeev V; Breton-Provencher, Vincent et al. (2016) Jointly reduced inhibition and excitation underlies circuit-wide changes in cortical processing in Rett syndrome. Proc Natl Acad Sci U S A 113:E7287-E7296
Ji, Xiong; Dadon, Daniel B; Powell, Benjamin E et al. (2016) 3D Chromosome Regulatory Landscape of Human Pluripotent Cells. Cell Stem Cell 18:262-75

Showing the most recent 10 out of 16 publications