Amyotrophy lateral sclerosis (ALS) and frontal temporal lobe degeneration (FTLD) are neurodegenerative diseases that mainly affect motor neurons in the brain and spinal cord, as well as cerebral cortological neurons, which in turn lead to muscle weakness and dementia.
, a variety of disease-caused genes have been found in ALS and FLD, most of which are involved in the pathogenesis of both diseases.
, however, the molecular mechanisms of these diseases are unclear and no strong treatment strategies have been developed.
One of the most important pathological features of the disease is the TAR DNA binding protein (TDP)-43, which disappears from the nucleosis and is abnormally deposited into the cytoste of the affected neurons (TDP-43 protein disease), which can be observed in many cases of mutations in pathogenic genes.
misalposition and abnormal deposition (TDP-43 protein disease) of TDP-43 in cytopseum is a hallmark of ALS and FLD neurons.
, however, the pathogenic mechanism of TDP-43-related diseases is not yet known.
We assume that TDP-43 cannot transport mRNA to neuron axons and may cause neurodegenerative changes in ALS and FLD, and try to study the function of TDP-43 by determining the axon transport target mRNA of TDP-43.
we found that in the axons of cortological neurons, shRNA-mediated TDP-43 gene knockout reduced mRNAs associated with translation function, including nuclear glycoprotein (RPs).
TDP-43 is combined and transshipmented with RP-mRNAs through its 5' end oligosine zone and the 5' end non-translation zone in the downstream GC region.
We have demonstrated through in vitro and in vivo models that RP-mRNAs are translated and integrated into the natural rnucose body of the axon, thus maintaining the function of the axon kernel, which is necessary for local protein synthesis to cope with the stimulation and pressure of the axon.
also found a decrease in RP-mRNAs in the cone bundles of patients with exudable ALS.
Our results illustrate the new function of TDP-43 in controlling RP-mRNAs transport and local translation of rnucose bodies to maintain the morphological integrity of neuron axons, and demonstrate the effect of this function of TDP-43 on neurodegenerative variants of ALS and FLD associated with TDP-43 protein disease.
: The total RNA of brain white mass was extracted from 6 frozen preserved brain tablets (each 100 m thick) in 21-day-old mice (3 mice under each experimental condition).
laser microscope is also used for laser microscopy.
RNA is extracted from TRIZOL, and the reverse transcriptase reaction is described above.
after 20 cycles of PCR of cDNA using TaqMan Universal Master Mix II, no UNG (Applied Biological Systems), nCounter (nanochain technology) was used to interbreed and signal count with the probe, based on a single-cell gene expression protocol.
data is analyzed by nSolver Analysis Software 3.0.
provides, if required, the sequence of quotations and probe sets for analysis is available.
, we determined that RP-mRNAs were the target gene for TDP-43 transport to axons.
TDP-43 not only works in the axon transport of RP-mRNAs, but also in the main function of maintaining axon rnucose, which is essential for local protein synthesis.
Nagano, S., Jinno, J., Abdelhamid, R.F. et al. TDP-43 transports ribosomal protein mRNA to regulate axonal local translation in neuronal axons. Acta Neuropathol 140, 695-713 (2020). MedSci Original Source: MedSci Original Copyright Notice: All text, images and audio and video materials on this website that indicate "Source: Mets Medicine" or "Source: MedSci Original" are owned by Mets Medicine and are not authorized to be reproduced by any media, website or individual, and are authorized to be reproduced with the words "Source: Mets Medicine".
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