16 June 2015
DanStem Seminar by Joseph Klim, June 22, 2015
Dr. Joseph Klim, Stem Cell and Regenerative Biology Department, Harvard University. Title: Transcriptional and proteomic profiling of human pluripotent stem cell - derived motor neurons: implications for familial amyotrophic lateral.
Title: Transcriptional and proteomic profiling of human pluripotent stem cell - derived motor neurons: implications for familial amyotrophic lateral.
Monday, June 22, 2015, 12:00
CPR Seminar room Panum Building 6, 2nd floor
Amyotrophic lateral sclerosis (ALS) is a rapidly progressive, fatal neurodegenerative disease characterized by the selective loss of upper and lower motor neurons. The identification of genetic triggers (e.g. mutations in C9ORF72, SOD1, FUS, and TARDBP)has informed our biological understanding of this devastating disease, but we still do not know how mutations in these genes cause selective motor neuron degeneration. Global, large-scale molecular studies on disease-relevant cell types is an attractive option to investigate the pathology of ALS, but the inaccessibility of human motor neurons combined with our inability to expand them in culture like cancer cells remains a barrier to these types of studies. Opportunely, human pluripotent stem cells can be directed to efficiently differentiate into substantial quantities of motor neurons. Here, we combined pluripotent stem cell technologies with both RNA sequencing and mass spectrometry-based proteomics to map alterations to mRNA and protein levels in motor neurons expressing mutant SOD1. Specifically, we introduced the severe SOD1 A4V mutation into a stem cell line that reports for GFP under the control of the motor neuron-specific promoter for HB9. This approach enabled us to study the effects of mutant SOD1 in purified populations of motor neurons using multiple metrics over time. These investigations have afforded an unprecedented glimpse at the biochemical make-up of human stem cell-derived motor neurons and how they change in culture. Moreover, our results revealed subtle yet reproducible differences in gene and protein expression between motor neurons with and without the SOD1 A4V mutation. Interestingly, several of the altered proteins regulate aspects of neuronal excitability, which our group previously described a hyper-excitability phenotype induced by mutant SOD1 in motor neurons. In conclusion, our global profiling efforts offer a greater understanding of stem cell-derived neurons and provide possible links between mutant proteins and molecular pathology. Perhaps their greatest value, however, is in identifying new therapeutic targets for intervention into the disease course of ALS.