Biology subjects

Crippa, V.

Publications and source records attributed to Crippa, V..

4 recordsLinked to original sources

bioRxiv2026

A Human Neuronal Cell Model of Endogenous TDP-43 A315T Reveals Altered Protein Dynamics and Disease-Relevant Cellular Dysfunction

TAR DNA-binding protein 43 (TDP-43) aggregation is the defining pathological hallmark of nearly all cases of amyotrophic lateral sclerosis (ALS), yet physiologically relevant human models that faithfully recapitulate disease-associated TDP-43 proteinopathy and dysfunction remain limited. To cover this gap, we generated a novel human-based model of cortical neurons carrying the endogenous ALS-linked TDP-43 A315T mutation together with an in-frame Dendra2 fluorescent reporter, enabling temporal and spatial monitoring of the protein. Neurons expressing TDP-43 A315T exhibited progressive neurite degeneration, altered neuronal activity, and impaired mitochondrial respiration, recapitulating several ALS-associated phenotypes. Our model also displays autophagy-dependent accumulation of cytoplasmic aggregates of mutant TDP-43 without overt loss of nuclear function, maintaining normal processing of canonical cryptic exon targets. In contrast, experimental induction of TDP-43 nuclear exclusion readily triggered cryptic exon incorporation, demonstrating that the model faithfully reproduces loss-of-function phenotypes under stress conditions. In line with perturbed protein solubility, mutant TDP-43 neurons show increased stress granule (SG) formation at baseline and under oxidative stress condition. Finally, treatment with the RNA chaperone Clip34 significantly reduced TDP-43 aggregation under both basal and oxidative stress conditions as well as its localization to SGs. Taken together, these findings establish a physiologically relevant human model that separates early TDP-43 toxic gain-of-function from basal loss-of-function while providing a robust platform for investigating TDP-43 biology and accelerating therapeutic discovery in ALS.

neuroscience↗

bioRxiv2026

Corticospinal propagation of full-length TDP-43 toxicity drives brain-to-muscle pathology

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive degeneration of upper and lower motor neurons. Cytoplasmic inclusions containing TAR DNA-binding protein 43 (TDP-43), a key regulator of RNA metabolism, represent a pathological hallmark of all sporadic (sALS) and most familial (fALS) forms, underscoring its central role in disease pathophysiology. In affected neurons, full-length (FL) TDP-43 undergoes nuclear-to-cytoplasmic mislocalization, leading to aggregation and cellular dysfunction, and can be released to propagate pathology across neural and non-neural circuits. However, the in vivo toxicity and spreading capacity of FL TDP-43 remain poorly defined. Here, we show that purified, stable human FL TDP-43 was readily internalized by neuronal cells, where it induced aggregation and significantly reduced cell viability. In vivo, an acute unilateral stereotaxic infusion of FL TDP-43 into the rat primary motor cortex was sufficient to trigger a robust centrifugal propagation of pathology along the corticospinal axis and beyond the central nervous system (CNS). TDP-43 pathology spread from the motor cortex to the spinal cord and reached skeletal muscle. At the cellular level, propagated pathology was characterized by intraneuronal phosphorylated TDP-43 (pTDP-43) inclusions, accumulation of high-molecular-weight TDP-43 species, region-specific neurodegeneration, and pronounced mitochondrial vulnerability. Notably, skeletal muscle displayed impaired mitochondrial bioenergetics, accompanied by both motor and non-motor behavioral deficits. Collectively, our findings demonstrate neuron-to-neuron, brain-to-spinal cord and brain-to-muscle spreading of FL TDP-43 toxicity in vivo, establishing a mechanistic link between central TDP-43 pathology and peripheral dysfunction. This work identifies FL TDP-43 as an active driver of disease spreading in ALS and provides the basis for a non-transgenic, TDP-43-driven rat model of disease propagation.

neuroscience↗

bioRxiv2023

Evolutionary signatures of human cancers revealed via genomic analysis of over 35,000 patients

By leveraging the ever-increasing availability of cancer omics data and the continuous advances in cancer data science and machine learning, we have discovered the existence of cancer type-specific evolutionary signatures associated with different disease outcomes. These signatures represent "favored trajectories" of acquisition of driver mutations that are repeatedly detected in patients with similar prognosis. In this work, we present a novel framework named ASCETIC (Agony-baSed Cancer EvoluTion InferenCe) that extracts such signatures from NGS experiments generated by different technologies such as bulk and single-cell sequencing data. In our study, we applied ASCETIC to (i) single-cell sequencing data from 146 patients with distinct myeloid malignancies and bulk whole-exome sequencing data from 366 acute myeloid leukemia patients, (ii) multi-region sequencing data from 100 early-stage lung cancer patients from the TRACERx project, (iii) whole-exome/genome sequencing data from more than 10,000 Pan-Cancer Atlas samples, and (iv) targeted bulk sequencing data from more than 25,000 MSK-MET metastatic patients (both datasets including multiple cancer types). As a result, we extracted different cancer (sub)type-specific single-nucleotide variants evolutionary signatures associated with clusters of patients with statistically significant different prognoses. In addition, we conducted several validations using diverse and previously unexplored datasets to evaluate the reliability and applicability of the evolutionary signatures extracted by ASCETIC. Such analyses provided evidence of the robustness and generalizability of the identified evolutionary patterns.

genetics↗

bioRxiv2019

BAG3 Pro209 mutants associated with myopathy and neuropathy sequester chaperones of the CASA-complex in aggresomes

Three missense mutations targeting the same proline 209 (Pro209) codon in the co-chaperone Bcl2-associated athanogene 3 (BAG3) have been reported to cause distal myopathy, dilated cardiomyopathy or Charcot-Marie-Tooth type 2 neuropathy. Yet, it is unclear whether distinct molecular mechanisms underlie the variable clinical spectrum of the rare patients carrying these three heterozygous Pro209 mutations in BAG3. Here, we studied all three variants and compared them to the BAG3_Glu455Lys mutant, which causes dilated cardiomyopathy. We found that all BAG3_Pro209 mutants have acquired a toxic gain-of-function, which causes these variants to accumulate in the form of insoluble HDAC6- and vimentin-positive aggresomes. The aggresomes formed by mutant BAG3 led to a relocation of other chaperones such as HSPB8 and Hsp70, which, together with BAG3, promote the so-called chaperone-assisted selective autophagy (CASA). As a consequence of their increased aggregation-proneness, mutant BAG3 trapped ubiquitinylated client proteins at the aggresome, preventing their efficient clearance. Combined, these data show that all BAG3_Pro209 mutants, irrespective of their different clinical phenotypes, are characterized by a gain-of-function that contributes to the gradual loss of protein homeostasis.

cell biology↗