Authors:

Joachim Gonzalez

Date Created:

Not specified

Course Title:

Professor:

Not specified

About Paper:

Human brain development is a highly complex process which requires exquisite orchestration. Thyroid hormone (TH) is one of these key orchestrators, as suboptimal levels of TH during gestation leads to abnormal brain development and reduced IQ. TH has a known. role in some cell type differentiation, its function in neuronal differentiation remains unknown. Our lab's previous work found that iPSC-derived neurons cultured with TH have higher maturation. Moreover, RNA-seq analysis showed that four of the most upregulated genes in the mature neurons were within the DLK1-D/O3 imprinted domain. DIO3 is a known repressor of TH signaling, and this result led us to hypothesize that genes within the DLK1-D/O3 imprinted domain were playing a role in neuronal differentiation. To address this hypothesis, we cultured a new batch of iPSC-derived neurons and collected mRNA at DO, D10, D20 and D40 and performed RT-qPCR studies to identify the expression pattern of the DLK1-D/O3 imprinted domain throughout neuronal differentiation. We also assayed DIO3 enzymatic activity at the different time points. Lastly, we cultured the neurons in excess TH to analyze whether excess TH presence causes differential gene expression of the locus. We found that mRNA transcript expression of all five genes we tested increased significantly throughout neuronal differentiation. Furthermore, DIO3 enzymatic activity increased by nearly 600% between DO and D40. Lastly, mRNA transcript expression of two genes in the locus, DLK1 and DIO3, increased significantly in neurons cultured with excess TH. We conclude that the entire DLK7-D/O3 imprinted domain is upregulated during neuronal differentiation and, in the case of DIO3 specifically, this translates to an increase in enzymatic activity.

Source:

University of Chicago

Topics:

No topics listed

Co-authors:

Joachim Gonzalez