Biology subjects

Perez-Navarro, E.

Publications and source records attributed to Perez-Navarro, E..

4 recordsLinked to original sources

bioRxiv2026

Targeted 3'-end RNA sequencing uncovers cryptic polyadenylation in Huntington's disease linked to somatic instability and CAG repeat purity

Huntingtons disease (HD) is a progressive neurodegenerative disorder caused by expanded CAG repeats in the first exon of the HTT gene, which encodes for huntingtin (HTT) protein. Full-penetrance is established at 40 repeats, but beyond, somatic repeat instability in the brain and CAG repeat purity modulate disease onset and severity. Previous studies have described that expanded repeats induce the incomplete splicing of HTT intron 1 to express the most pathogenic HTT isoform, known as HTT1a. Yet, the lack of a robust and sensitive method to evaluate HTT RNA-misprocessing has limited our understanding of HTT1a expression in HD pathophysiology. Here we describe a targeted RNA sequencing approach, known as 3-end targeted RNA sequencing or 3TRS, to simultaneously quantify multiple HTT transcripts generated by canonical and cryptic polyadenylation in several HD models. We show that activation of HTT cryptic polyadenylation is highly selective and requires long and uninterrupted CAG repeat expansions. In HD knock-in mice and human postmortem brain, cryptic HTT expression strongly correlates with brain-specific somatic repeat instability, supporting a model where ultralong and unstable CAG repeats drive toxicity by activating HTT RNA-misprocessing. Overall, 3TRS provides a robust framework to investigate HTT1a biogenesis and expression and to evaluate HTT-lowering therapeutic strategies. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/697463v2_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@168d8e1org.highwire.dtl.DTLVardef@76ba3forg.highwire.dtl.DTLVardef@bdaf93org.highwire.dtl.DTLVardef@151e581_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2020

A wide-ranging Pseudomonas aeruginosa PeptideAtlas build: a useful proteomic resource for a versatile pathogen.

Pseudomonas aeruginosa is an important opportunistic pathogen with high prevalence in nosocomial infections. This microorganism is a good model for understanding biological processes such as the quorum-sensing response, the metabolic integration of virulence, the mechanisms of global regulation of bacterial physiology, and the evolution of antibiotic resistance. Till now, P. aeruginosa proteomic data, although available in several on-line repositories, were dispersed and difficult to access. In the present work, proteomes of the PAO1 strain grown under very different conditions and from diverse cellular compartments have been analyzed and joined to build the Pseudomonas PeptideAtlas. This resource is a comprehensive mass spectrometry-derived peptide and inferred protein database with 71.3% coverage of the total predicted proteome of P. aeruginosa PAO1. This is the highest published coverage among the eight bacterial PeptideAtlas datasets currently available. The proteins in the Pseudomonas PeptideAtlas cover 84% of metabolic proteins, 71% of proteins involved in genetic information processing, 72% of proteins responsible for environmental information processing, more than 80% of proteins related to quorum sensing and biofilm formation, and 81% of proteins responsible for antimicrobial resistance. It exemplifies a necessary tool for targeted proteomics studies, system-wide observations, and cross-species observational studies. Here we describe how this resource was built and some of the physiologically important proteins of this pathogen. SignificancePseudomonas aeruginosa is among the most versatile bacterial pathogens. Studies of its proteome are very important as they can reveal virulence factors and mechanisms of antibiotic resistance. The construction of a proteomic resource such as the PeptideAtlas enables targeted proteomics studies, system-wide observations, and cross-species observational studies.

microbiology↗

bioRxiv2020

SYNAPTIC RTP801 CONTRIBUTES TO MOTOR LEARNING DYSFUNCTION IN HUNTINGTON DISEASE

RTP801/REDD1 is a stress responsive protein that mediates mutant huntingtin (mhtt) toxicity in cellular models and is up regulated in Huntingtons disease (HD) patients putamen. Here, we investigated whether RTP801 is involved in motor impairment in HD by affecting striatal synaptic plasticity. Ectopic mhtt was over expressed in cultured rat primary neurons. The protein levels of RTP801 were assessed in homogenates and crude synaptic fractions from human postmortem HD brains and mouse models of HD. Striatal RTP801 expression was knocked down with adeno-associated viral particles containing a shRNA in the R6/1 mouse model of HD and motor learning was then tested. Ectopic mhtt elevated RTP801 in synapses of cultured neurons. RTP801 was also up regulated in striatal synapses from HD patients and mouse models. Knocking down RTP801 in the R6/1 mouse striatum prevented motor learning impairment. RTP801 silencing normalized the Ser473 Akt hyperphosphorylation by downregulating Rictor and it induced synaptic elevation of calcium permeable GluA1 subunit and TrkB receptor levels, suggesting an enhancement in synaptic plasticity. These results indicate that mhtt-induced RTP801 mediates motor dysfunction in a HD murine model, revealing a potential role in the human disease. These findings open a new therapeutic framework focused on the RTP801/Akt/mTOR axis.

neuroscience↗

bioRxiv2020

Neuron-specific increase in lamin B1 disrupts nuclear function in Huntington's disease

Lamins are crucial proteins for nuclear functionality. Here, we provide new evidence showing an involvement of increased lamin B1 levels in the pathophysiology of Huntingtons disease (HD), a CAG repeat-associated neurodegenerative disorder. Through fluorescence-activated nuclear suspension imaging we demonstrate that nucleus from striatal medium-sized spiny and CA1 hippocampal neurons display increased lamin B1 levels, in correlation with altered nuclear morphology and nucleocytoplasmic transport disruption. Moreover, ChIP-sequencing analysis shows an alteration of lamin-associated chromatin domains in hippocampal nuclei, which could contribute to transcriptional alterations we determined by RNA sequencing. Supporting lamin B1 alterations as a causal role in mutant-huntingtin mediated neurodegeneration, pharmacological normalization of lamin B1 levels by betulinic acid administration in the R6/1 mouse model of HD restored nuclear homeostasis and prevented motor and cognitive dysfunction. Collectively, our work point out increased lamin B1 levels as a new pathogenic mechanism in HD and provides a novel target for its intervention.

neuroscience↗