Biology subjects

Borras, E.

Publications and source records attributed to Borras, E..

4 recordsLinked to original sources

bioRxiv2024

Enhanced proteome profiling of human cerebrospinal fluid using a commercial plasma enrichment strategy

Cerebrospinal fluid (CSF) is a valuable liquid biopsy for identifying protein biomarkers in neurological diseases, yet its proteome profiling faces challenges due to the large dynamic range of protein abundances. In this study, we assessed the effectiveness of a commercial enrichment strategy, initially developed for plasma samples, in enhancing the detection of low-abundance proteins in human CSF. We demonstrate significant improvements in protein identification and coverage depth while maintaining high reproducibility and low coefficients of variation. These findings underscore the potential of this enrichment strategy to facilitate rapid and sensitive CSF analysis, advancing biomarker discovery in neurological research.

molecular biology↗

bioRxiv2023

Peroxiredoxinylation buffers the redox state of the proteome upon cellular stress

The redox state of proteins is essential for their function and guarantees cell fitness. Peroxiredoxins protect cells against oxidative stress, maintain redox homeostasis, act as chaperones and transmit hydrogen peroxide signals to redox regulators. Despite the profound structural and functional knowledge of peroxiredoxins action, information on how the different functions are concerted is still scare. Using global proteomic analyses, we show here that the yeast peroxiredoxin Tsa1 binds hundreds of proteins of essential biological processes, including protein turnover and carbohydrate metabolism. Several of these interactions are of covalent nature and failure of this peroxiredoxinylation leads to global changes in the metabolome and reduced stress resistance. Thioredoxins directly remove TSA1-formed mixed disulfide intermediates, thus expanding the role of the thioredoxin-peroxiredoxin redox cycle pair to buffer the redox state of proteins in an unprecedented way.

biochemistry↗

bioRxiv2023

IKK1 kinase coordinates BRD4 and JAK/STAT signaling to subvert DNA damage-based anticancer therapy

Activation of the IKK kinase complex has recurrently been linked to colorectal cancer (CRC) initiation and progression. However, identification of downstream effectors other than NF-{kappa}B has remained elusive. Analysis of IKK-dependent substrates after UV-treatment revealed that BRD4 phosphorylation by IKK is required for chromatin-binding dynamics upon damage. Moreover, IKK induces the NF-{kappa}B-dependent transcription of LIF leading to STAT3 activation, association of BRD4 to STAT3 and recruitment to specific target genes. IKK abrogation results in defective BRD4 and STAT3 function leading to irreparable DNA damage and apoptotic cell death upon different stimuli. Simultaneous inhibition of BRAF-dependent IKK activity or BRD4 and the JAK/STAT pathway enhanced the therapeutic potential of 5-FU plus irinotecan in CRC cells, and is curative in a chemotherapy-resistant CRC xenograft model. Coordinated expression of LIF and IKK is a poor prognosis marker for CRC patients. Our data uncover a functional link between IKK, BRD4 and JAK/STAT signaling with clinical relevance.

cancer biology↗

bioRxiv2023

SMARCAD1 and TOPBP1 contribute to heterochromatin maintenance at the transition from the 2C-like to the pluripotent state

Chromocenters are established after the 2-cell (2C) stage during mouse embryonic development, but the factors that mediate chromocenter formation remain largely unknown. To identify regulators of 2C heterochromatin establishment, we generated an inducible system to convert embryonic stem cells (ESCs) to 2C-like cells. This conversion is marked by a global reorganization and dispersion of H3K9me3-heterochromatin foci, which are then reversibly formed upon re-entry into pluripotency. By profiling the chromatin-bound proteome (chromatome) through genome capture of ESCs transitioning to 2C-like cells, we uncover chromatin regulators involved in de novo heterochromatin formation. We identified TOPBP1 and investigated its binding partner SMARCAD1. SMARCAD1 and TOPBP1 associate with H3K9me3-heterochromatin in ESCs. Interestingly, the nuclear localization of SMARCAD1 is lost in 2C-like cells. SMARCAD1 or TOPBP1 depletion in mouse embryos leads to developmental arrest, reduction of H3K9me3, and remodeling of heterochromatin foci. Collectively, our findings contribute to comprehending the maintenance of chromocenters during early development.

developmental biology↗