Biology subjects

Berning, B. A.

Publications and source records attributed to Berning, B. A..

2 recordsLinked to original sources

bioRxiv2023

A transient protein folding response targets aggregation in the early phase of TDP-43-mediated disease

Understanding the mechanisms that drive TDP-43 pathology is integral to combating neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). To address this, we sought to determine the timeline of proteomic alterations across disease course in TDP-43 proteinopathy. Using longitudinal quantitative proteomics analysis of cortex samples from the cytoplasmic TDP-43 rNLS8 mouse model of ALS and FTLD, we identified several distinct protein subsets characterized by temporal alterations in protein abundance across diverse biological pathways, including protein folding, intracellular transport, myelination, and neuronal synaptic function. Remarkably, neurons in the rNLS8 cortex elicited a transitory response primarily comprising protein-folding factors prior to and in the earliest stages of disease progression. This response included increased levels of DnaJ homolog subfamily B member 5, DNAJB5, and proof-of-concept studies showed that DNAJB5 over-expression decreased TDP-43 aggregation in cell and cortical neuron cultures. Conversely, knockout of Dnajb5 exacerbated motor impairments caused by AAV-mediated cytoplasmic TDP-43 expression in the brains and spinal cords of mice. Lastly, the late disease proteomic signatures of rNLS8 mouse cortex strongly correlated with changes in human autopsy-derived TDP-43 proteinopathy tissues, indicating commonality of disease processes. Together, these findings reveal molecular mechanisms that regulate protein levels through distinct stages of ALS and FTLD progression, and suggest that protein folding factors that combat cytoplasmic TDP-43 protein aggregation could be protective in disease. HighlightsO_LIThe first longitudinal map of the cortex proteome throughout TDP-43-driven disease in a mouse model of cytoplasmic TDP-43 proteinopathy (rNLS8 mice). C_LIO_LICytoplasmic TDP-43 accumulation drives many dynamic changes to the cortex proteome, including increases in protein folding factors prior to disease onset. C_LIO_LIThe protein folding factor DNAJB5 decreases TDP-43 aggregation in HEK293 cells and primary cortical neurons and Dnajb5 knockout exacerbates cytoplasmic TDP-43-associated motor impairments in vivo. C_LIO_LIThe proteomic signature of the rNLS8 mouse cortex correlates strongly with postmortem brain tissue from human TDP-43 proteinopathies. C_LIO_LIA new webtool, TDP-map (https://shiny.rcc.uq.edu.au/TDP-map/), allows comparison of transcriptomic and proteomic datasets from mouse and human TDP-43 proteinopathy. C_LI

neuroscience↗

bioRxiv2019

Riluzole does not ameliorate disease caused by cytoplasmic TDP-43 in a mouse model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease commonly treated with riluzole, a small molecule that may act via modulation of glutamatergic neurotransmission. However, riluzole only modestly extends lifespan for people living with ALS and its precise mechanisms of action remain unclear. Most ALS cases are characterised by accumulation of cytoplasmic TAR DNA binding protein of 43 kDa (TDP-43), and understanding the effects of riluzole in models that closely recapitulate TDP-43 pathology may provide insights for development of improved therapeutics. We therefore investigated the effects of riluzole in transgenic mice that inducibly express nuclear localisation sequence (NLS)-deficient human TDP-43 in neurons (NEFH-tTA/tetO-hTDP-43{Delta}NLS, rNLS, mice). Riluzole treatment from the first day of hTDP-43{Delta}NLS expression did not alter disease onset, weight loss or performance on multiple motor behavioural tasks. Riluzole treatment also did not alter TDP-43 protein levels, solubility or phosphorylation. Although we identified a significant decrease in GluA2 and GluA3 proteins in the cortex of rNLS mice, riluzole did not ameliorate this disease-associated molecular phenotype. Likewise, riluzole did not alter the disease-associated atrophy of hindlimb muscle in rNLS mice. Finally, riluzole treatment beginning after disease onset in rNLS mice similarly had no effect on progression of late-stage disease or animal survival. Together, we demonstrate specific glutamatergic receptor alterations and muscle fibre-type changes reminiscent of ALS in rNLS mice, but riluzole had no effect on these or any other disease phenotypes. Future targeting of pathways directly related to accumulation of TDP-43 pathology may be needed to develop better treatments for ALS. Significance StatementAccumulation of cytoplasmic TDP-43 protein is the hallmark pathology of ALS. Riluzole is the most widely used drug for ALS treatment, but provides only a short extension of lifespan. We demonstrate here in the rNLS mouse model, which mimics TDP-43 pathology, that riluzole does not ameliorate progressive alterations in motor strength and coordination, muscle atrophy, glutamate receptor levels, or TDP-43 protein levels and solubility, and does not prolong animal survival. Riluzole similarly did not affect decreased levels of glutamate receptor subunits GluA2/GluA3 in rNLS mice. The inability of riluzole to rescue pathological or phenotypic changes in this TDP-43 model provides further impetus for the discovery of improved therapies targeting the key drivers of ALS pathogenesis.

neuroscience↗