GSE22351
Altered Distributions of SMN-containing GEMs and Mitochondria in Motor Neurons of TDP-43 transgenic Mice
TDP-43, a DNA/RNA binding protein involved in RNA transcription and splicing has been associated with the pathophysiology of neurodegenerative diseases, including ALS. However, the function of TDP-43 in motor neurons remains undefined. Here, we employ both gain- and loss-of-function approaches to determine roles of TDP-43 in motor neurons. Mice expressing human TDP-43 in neurons exhibited growth retardation and premature death that are characterized by abnormal intranuclear inclusions comprised of TDP-43 and Fused in Sarcoma (FUS), and massive accumulation of mitochondria in TDP-43-negative cytoplasmic inclusions in motor neurons, lack of mitochondria in motor axon terminals and immature neuromuscular junctions. Whereas elevated level of TDP-43 disrupts the normal nuclear distribution of Survival Motor Neuron (SMN)-associated Gemini of coiled bodies (GEMs) in motor neurons, its absence prevents the formation of GEMs in the nuclei of these cells. Moreover, transcriptome-wide deep sequencing analysis revealed that decrease in abundance of neurofilament transcripts contributed to the reduction of caliber of motor axons in TDP-43 mice. In concert, our findings indicate that TDP-43 participates in pathways critical for motor neuron physiology, including those that regulate the normal distributions of SMN-associated GEMs in the nucleus and mitochondria in the cytoplasm. Overall design: Human TDP-43 coding region were inserted into pThy1.2 expression cassette and subsequently injected into C57BL/6;SJL hybrid mouse embryos to make human TDP-43 transgenic mice