Curated Optogenetic Publication Database

Abstract: Aberrant aggregation of the prion-like RNA binding protein TDP-43 drives several fatal neurodegenerative proteinopathies, including amyotrophic lateral sclerosis (ALS). In this work, we define how short, specific RNAs solubilize TDP-43. These short RNAs engage and stabilize the TDP-43 RNA recognition motifs, which allosterically destabilizes a conserved helical region in the prion-like domain, thereby promoting aggregation-resistant conformers. Sequence-space mining identified short RNA chaperones with enhanced activity against TDP-43 and disease-linked variants. Enhanced short RNA chaperones mitigated aberrant TDP-43 phenotypes in optogenetic models and in ALS patient-derived and control motor neurons. In mice with cytoplasmic TDP-43 aggregation and motor neuron loss, an enhanced short RNA chaperone reduced pathological aggregation, restored TDP-43 function, and conferred neuroprotection. These results define a mechanistic and therapeutic framework for RNA-based strategies to counter TDP-43 proteinopathies.

Abstract: RNA-binding proteins (RBPs) with prion-like domains (PrLDs), such as FUS and TDP-43, condense into functional liquids, which can transform into pathological fibrils that underpin fatal neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS)/frontotemporal dementia (FTD). Here, we define short RNAs that prevent FUS fibrillization by promoting liquid phases and distinct short RNAs that prevent and reverse FUS condensation and fibrillization. These activities require interactions with multiple RNA-binding domains of FUS and are encoded by RNA sequence, length, and structure. We define a short RNA that dissolves cytoplasmic FUS aggregates, restores nuclear FUS, and mitigates FUS toxicity in optogenetic models and ALS patient-derived motor neurons. Another short RNA dissolves cytoplasmic TDP-43 aggregates, restores nuclear TDP-43, and mitigates TDP-43 toxicity. Since short RNAs can be effectively delivered to the human brain, these oligonucleotides could have utility for ALS/FTD and related disorders.

Abstract: TDP-43 proteinopathy is a pathological hallmark of amyotrophic lateral sclerosis and frontotemporal dementia where cytoplasmic TDP-43 inclusions are observed within degenerating regions of patient postmortem tissue. The mechanism by which TDP-43 aggregates has remained elusive due to technological limitations, which prevent the analysis of specific TDP-43 interactions in live cells. We present an optogenetic approach to reliably induce TDP-43 proteinopathy under spatiotemporal control. We show that the formation of pathologically relevant inclusions is driven by aberrant interactions between low-complexity domains of TDP-43 that are antagonized by RNA binding. Although stress granules are hypothesized to be a conduit for seeding TDP-43 proteinopathy, we demonstrate pathological inclusions outside these RNA-rich structures. Furthermore, we show that aberrant phase transitions of cytoplasmic TDP-43 are neurotoxic and that treatment with oligonucleotides composed of TDP-43 target sequences prevent inclusions and rescue neurotoxicity. Collectively, these studies provide insight into the mechanisms that underlie TDP-43 proteinopathy and present a potential avenue for therapeutic intervention.