Biology subjects

Franco-Flores, A. K.

Publications and source records attributed to Franco-Flores, A. K..

3 recordsLinked to original sources

bioRxiv2024

Transcriptome-based screening in TARDBP/TDP-43 knock-in motor neurons identifies the NEDD8-activating enzyme inhibitor MLN4924

A growing body of knowledge implicates perturbed RNA homeostasis in amyotrophic lateral sclerosis (ALS), a neurodegenerative disease that currently has no cure and few available treatments. Dysregulation of the multifunctional RNA-binding protein TDP-43 is increasingly regarded as a convergent feature of this disease, evidenced at the neuropathological level by the detection of TDP-43 pathology in most patient tissues, and at the genetic level by the identification of disease-associated mutations in its coding gene TARDBP. To characterize the transcriptional landscape induced by TARDBP mutations, we performed whole-transcriptome profiling of motor neurons differentiated from two knock-in iPSC lines expressing the ALS-linked TDP-43 variants p.A382T or p.G348C. Our results show that the TARDBP mutations significantly altered the expression profiles of mRNAs and microRNAs of the 14q32 cluster in MNs. Using mutation-induced gene signatures and the Connectivity Map database, we identified compounds predicted to restore gene expression toward wild-type levels. Among top-scoring compounds selected for further investigation, the NEDD8-activating enzyme inhibitor MLN4924 effectively improved cell viability and neuronal activity, highlighting a possible role for protein post-translational modification via NEDDylation in the pathobiology of TDP-43 in ALS.

neuroscience↗

bioRxiv2023

Homozygous ALS-linked mutations in TARDBP/TDP-43 lead to progressive synaptic dysfunction in human iPSC-derived motor neurons

Cytoplasmic mislocalization and aggregation of the RNA-binding protein TDP-43 is a pathological hallmark of the motor neuron (MN) disease amyotrophic lateral sclerosis (ALS). Furthermore, while mutations in the TARDBP gene (encoding TDP-43) have been associated with ALS, the pathogenic consequences of these mutations remain poorly understood. Using CRISPR/Cas9, we engineered two homozygous knock-in iPSC lines carrying mutations in TARDBP encoding TDP-43A382T and TDP-43G348C, two common yet understudied ALS TDP-43 variants. MNs differentiated from knock-in iPSCs had normal viability and displayed no significant changes in TDP-43 subcellular localization, phosphorylation, solubility, or aggregation compared with isogenic control MNs. However, our results highlight synaptic impairments in both TDP-43A382T and TDP-43G348C MN cultures, as reflected in synapse abnormalities and alterations in spontaneous neuronal activity. Collectively, our findings suggest that MN dysfunction may precede the occurrence of TDP-43 pathology and neurodegeneration in ALS and further implicate synaptic and excitability defects in the pathobiology of this disease.

neuroscience↗

bioRxiv2022

An optimized workflow to generate and characterize iPSC-derived motor neuron (MN) spheroids

Motor neuron diseases (MNDs) are characterized by the progressive degeneration of motor neurons (MNs) from the cortex, brainstem and/or the spinal cord. In an effort to understand the underlying causes of this selective degeneration, a multitude of in vitro models based on induced pluripotent stem cell (iPSC)-derived MNs have been developed. Moreover, different groups have started to use advanced 3D structures, composed of MNs and other cell types to increase the physiological relevance of such in vitro models. For instance, spheroids are simple 3D models that have the potential to be generated in large numbers that can be used across different assays. In this study, we generated MN spheroids and developed a workflow to analyze them. We confirmed the expression of different MN markers as the MN spheroids differentiate, at both the transcript and protein level, as well as their capacity to display functional activity in the form of action potentials (APs) and bursts. We also identified the presence of other cell types, namely interneurons and oligodendrocytes, which share the same neural progenitor pool with MNs. In summary, we successfully developed a MN 3D model, and we optimized a workflow that can be applied to their characterization and analysis. In the future, we will apply this model and workflow to the study of MNDs by generating MN spheroids from patient-derived iPSC lines, aiming to contribute to the development of more advance and physiological in vitro disease models.

neuroscience↗