T-REX17 is a transiently expressed non-coding RNA essential for human endoderm formation

The Role of Long Non-Coding RNAs in Human Endoderm Differentiation

The human genome sequencing revealed a vast complexity of transcripts, with over 80% of the genome being transcribed into non-coding RNAs. In particular, long non-coding RNAs (lncRNAs) have emerged as critical regulators of various cellular processes, including embryonic development and stem cell differentiation. Despite extensive efforts to identify and characterize lncRNAs, defining their mechanisms of action in state-specific cellular contexts remains a significant challenge. Only recently has the involvement of lncRNAs in human endoderm differentiation of pluripotent stem cells begun to be addressed, creating an opportunity to explore the mechanisms by which lncRNAs exert their functions in germ layer formation, lineage specification, and commitment. This review summarizes current findings on the roles of lncRNAs in endoderm differentiation, highlighting the functional mechanisms and regulatory aspects underlying their involvement in cell fate decisions leading to endoderm development. The key lncRNAs implicated in endoderm differentiation are discussed, along with their interaction with transcription factors and RNA-binding proteins and modulation of signaling pathways essential for endoderm development. Gaining insight into the regulatory roles of lncRNAs in endoderm differentiation enhances the understanding of developmental biology and provides a foundation for discovering novel lncRNAs involved in cell fate determination.

Long noncoding RNA as an emerging regulator of endoderm differentiation: progress and perspectives

Accumulated studies have demonstrated that long noncoding RNAs (lncRNAs) play crucial regulatory roles in diverse biological processes, such as embryonic development and cell differentiation. Comprehensive transcriptome analysis identifies extensive lncRNAs, gradually elucidating their functions across various contexts. Recent studies have highlighted the essential role of lncRNAs in definitive endoderm differentiation, underscoring their importance in early development. In this review, we have analyzed the features of overlapping, proximal, and desert lncRNAs, classified by genomic location, in pluripotent stem cells (PSCs) and the differentiation derivatives. Furthermore, we focus on the endoderm lineage and review the latest advancements in lncRNA identification and their distinct regulatory mechanisms. By consolidating current knowledge, we aim to provide a clearer perspective on how lncRNAs contribute to endoderm differentiation in different manners.

Developmental trajectories and cooperating genomic events define molecular subtypes of BCR::ABL1-positive ALL

ABSTRACT

Distinct diagnostic entities within BCR::ABL1-positive acute lymphoblastic leukemia (ALL) are currently defined by the International Consensus Classification of myeloid neoplasms and acute leukemias (ICC): "lymphoid only", with BCR::ABL1 observed exclusively in lymphatic precursors, vs "multilineage", where BCR::ABL1 is also present in other hematopoietic lineages. Here, we analyzed transcriptomes of 327 BCR::ABL1-positive patients with ALL (age, 2-84 years; median, 46 years) and identified 2 main gene expression clusters reproducible across 4 independent patient cohorts. Fluorescence in situ hybridization analysis of fluorescence-activated cell-sorted hematopoietic compartments showed distinct BCR::ABL1 involvement in myeloid cells for these clusters (n = 18/18 vs n = 3/16 patients; P < .001), indicating that a multilineage or lymphoid BCR::ABL1 subtype can be inferred from gene expression. Further subclusters grouped samples according to cooperating genomic events (multilineage: HBS1L deletion or monosomy 7; lymphoid: IKZF1-/- or CDKN2A/PAX5 deletions/hyperdiploidy). A novel HSB1L transcript was highly specific for BCR::ABL1 multilineage cases independent of HBS1L genomic aberrations. Treatment on current German Multicenter Study Group for Adult ALL (GMALL) protocols resulted in comparable disease-free survival (DFS) for multilineage vs lymphoid cluster patients (3-year DFS: 70% vs 61%; P = .530; n = 91). However, the IKZF1-/- enriched lymphoid subcluster was associated with inferior DFS, whereas hyperdiploid cases showed a superior outcome. Thus, gene expression clusters define underlying developmental trajectories and distinct patterns of cooperating events in BCR::ABL1-positive ALL with prognostic relevance.