Biology subjects

Jaffrezic, F.

Publications and source records attributed to Jaffrezic, F..

4 recordsLinked to original sources

bioRxiv2024

Human PrP E219K as a new and promising substrate for RT-QuIC amplification of human prion strains: a first step towards strain discrimination

Prion diseases are fatal neurodegenerative diseases that affect mammals through the transconformation of a host protein, the prion protein (PrP), into a toxic and pathogenic conformer termed PrPSc. Until now, the diagnosis is only confirmed with a post-mortem histology study of the central nervous system. Among the methods to detect the etiological agent, in vitro amplification techniques have emerged as very sensitive, highly specific and rapid tools, even though some prion strains remain refractory or difficult to amplify. Here we report the use of a new recombinant substrate for Real-Time Quaking Induced Conversion (RT-QuIC), a natural polymorphism of human prion protein with a lysine at position 219 instead of a glutamic acid, PrP E219K. This substrate amplifies the six sporadic human strains responsible for Creutzfeldt-Jakob Disease (CJD) and the strain responsible for its variant form in a few hours and over a large dilution range of the seeds. Moreover, based on the lag time of the amplification reactions, the PrP E219K substrate allows to discriminate between sporadic and variant CJD strains, a first step towards an ante-mortem typing of the prion strain affecting a patient.

pathology↗

bioRxiv2021

Potential genetic robustness of Prnp and Sprn double knockout mouse embryos towards ShRNA-lentiviral inoculation

Shadoo, encoded by Sprn, and PrP, encoded by Prnp, are related proteins whose biological functions are still incompletely understood. Although previous knockdown experiments have suggested the necessity of Shadoo in the absence of PrP during early mouse embryogenesis, little impact of the double-knockout of these two loci was reported. To further investigate this apparent discrepancy, we compared the transcriptome of WT, Prnp0/0 and Prnp0/0, Sprn0/0 E6.5 mouse embryos following inoculation by Sprn-ShRNA or Prnp-ShRNA lentiviral vectors at the one-cell stage. Our results highlighted a significant induction of an apoptotic pathway in Prnp0/0 E6.5 mouse embryos inoculated with Sprn-ShRNA vectors alongside interferon and to a lesser extent inflammatory responses, confirming previous reported experiments. On the contrary, ShRNA vector inoculation in Prnp0/0, Sprn0/0 embryos did not induce apoptosis and resulted in lower interferon responses. Finally, comparisons of the transcriptome of WT and Prnp0/0, Sprn0/0 embryos revealed only slight differences, which may in part explain the genetic robustness observed in the latter genotype. HighlightsO_LISprn-ShRNA lentivirus vector inoculation in Prnp knockout one-cell mouse embryos results in the induction of an apoptosis pathway at E6.5, alongside interferon and to a lesser extent inflammatory responses. C_LIO_LISprn- or Prnp-ShRNA lentivirus vector inoculations in Prnp/Sprn knockout one-cell mouse embryos induce lower interferon responses and no apoptotic pathway at E6.5. C_LIO_LIAlthough wild type and Prnp/Sprn knockout E6.5 mouse embryos are transcriptomically similar, some differences might explain this apparent resilience of the double knockout genotype. C_LI

genomics↗

bioRxiv2019

Individualized multi-omic pathway deviation scores using multiple factor analysis

SO_SCPLOWUMMARYC_SCPLOWMalignant progression of normal tissue is typically driven by complex networks of somatic changes, including genetic mutations, copy number aberrations, epigenetic changes, and transcriptional reprogramming. To delineate aberrant multi-omic tumor features that correlate with clinical outcomes, we present a novel pathway-centric tool based on the multiple factor analysis framework called padma. Using a multi-omic consensus representation, padma quantifies and characterizes individualized pathway-specific multi-omic deviations and their underlying drivers, with respect to the sampled population. We demonstrate the utility of padma to correlate patient outcomes with complex genetic, epigenetic, and transcriptomic perturbations in clinically actionable pathways in breast and lung cancer.

bioinformatics↗

bioRxiv2018

Fine-tuned adaptation of embryo-endometrium pairs at implantation revealed by gene regulatory networks

Interactions between embryo and endometrium at implantation are critical for the progression and the issue of pregnancy. These reciprocal actions involve exchange of paracrine signals that govern implantation and placentation. However, it remains unknown how these interactions between the conceptus and the endometrium are coordinated at the level of an individual pregnancy. Under the hypothesis that gene expression of endometrium is dependent on gene expression of extraembryonic tissues, we performed an integrative analysis of transcriptome profiles of paired conceptuses and endometria obtained from pregnancies initiated by artificial insemination. We quantified strong dependence (|r|>0.95, eFDR<0.01) in transcript abundance of genes expressed in the extraembryonic tissues and genes expressed in the endometrium. The profiles of connectivity revealed distinct co-expression patterns of extraembryonic tissues with caruncular and intercaruncular areas of the endometrium. Notably, a subset of highly co-expressed genes between conceptus (n=229) and caruncular areas of the endometrium (n=218, r>0.9999, eFDR<0.001) revealed a blueprint of gene expression specific to each pregnancy. Functional analyses of genes co-expressed between conceptus and endometrium revealed significantly enriched functional modules with critical contribution for implantation and placentation, including \"in utero embryonic development\", \"placenta development\" and \"regulation of transcription\". Functional modules were remarkably specific to caruncular or intercaruncular areas of the endometrium. The quantitative and functional association between genes expressed in conceptus and endometrium emphasize a coordinated communication between these two entities in mammals. To our knowledge, we provide first evidence that implantation in mammalian pregnancy relies on the ability of the conceptus and the endometrium to develop a fine-tuned adaptive response characteristic of each pregnancy.

developmental biology↗