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Sagniez, M.

Publications and source records attributed to Sagniez, M..

2 recordsLinked to original sources

Assembly Arena: Benchmarking RNA isoform reconstruction algorithms for nanopore sequencing

Resolving the transcriptomes of higher eukaryotes is more tangible with the advent of long read sequencing, which greatly facilitates the identification of new transcripts and their splicing isoforms. However, the computational analysis of long read RNA sequencing data remains challenging as it is difficult to disentangle technical artifacts from bona fide biological information. To address this, we evaluated the performance of multiple leading transcriptome assembly algorithms on their ability to accurately reconstruct RNA transcript isoforms. We specifically focused on deep nanopore sequencing of synthetic RNA spike-in controls (Sequins and SIRVs) across different chemistries, including cDNA and direct RNA protocols. Our systematic comparative benchmarking exposes the strengths and limitations of the different surveyed strategies. We also highlight conceptual and technical challenges with the annotation of transcriptomes and the formalization of assembly quality metrics. Our results complement similar recent endeavors, helping forge a path towards a gold standard analytical pipeline for long read transcriptome assembly.

bioinformatics↗

Directed differentiation of EA/TEF patient-derived induced pluripotent stem cells into esophageal epithelial organoids reveal SOX2 dysregulation at the anterior foregut stage

A series of well-regulated cellular and molecular events result in the compartmentalization of the anterior foregut into the esophagus and trachea. Disruption of the compartmentalization process leads to esophageal atresia/tracheoesophageal fistula (EA/TEF). Therefore, the objective is to differentiate pluripotent stem cells (PSCs), namely, embryonic stem cells and iPSCs from healthy individuals and iPSCs from EA/TEF type C patients, into mature 3-dimensional esophageal organoids expressing Involucrin, Keratin-4, -13, and p63. CXCR4, SOX17, and GATA4 expression was similar in both patient and healthy endodermal cells. Key transcription factor SOX2 was significantly lower in patient-derived anterior foregut. RNA sequencing revealed critical genes GSTM1 and RAB37 to be significantly lower in patient-derived anterior foregut. Furthermore, we observed an abnormal expression of NKX2.1 in the patient-derived mature esophageal organoids. We therefore hypothesize that a transient dysregulation of SOX2 and the abnormal expression of NKX2.1 in patient-derived cells could be responsible for the abnormal foregut compartmentalization.

developmental biology↗