Publications by authors named "Itamar Harel"

Mutations in genes involved in DNA damage repair (DDR) often lead to premature aging syndromes. While recent evidence suggests that inflammation, alongside mutation accumulation and cell death, may drive disease phenotypes, its precise contribution to pathophysiology remains unclear. Here, by modeling Ataxia Telangiectasia (A-T) and Bloom Syndrome in the African turquoise killifish ( ), we replicate key phenotypes of DDR syndromes, including infertility, cytoplasmic DNA fragments, and reduced lifespan.

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Protein aggregation is a hallmark of age-related neurodegeneration. Yet, aggregation during normal aging and in tissues other than the brain is poorly understood. Here, we leverage the African turquoise killifish to systematically profile protein aggregates in seven tissues of an aging vertebrate.

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Protein aggregation, which can sometimes spread in a prion-like manner, is a hallmark of neurodegenerative diseases. However, whether prion-like aggregates form during normal brain aging remains unknown. Here, we use quantitative proteomics in the African turquoise killifish to identify protein aggregates that accumulate in old vertebrate brains.

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Classical evolutionary theories propose tradeoffs among reproduction, damage repair and lifespan. However, the specific role of the germline in shaping vertebrate aging remains largely unknown. In this study, we used the turquoise killifish (Nothobranchius furzeri) to genetically arrest germline development at discrete stages and examine how different modes of infertility impact life history.

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Classical evolutionary theories propose tradeoffs between reproduction, damage repair, and lifespan. However, the specific role of the germline in shaping vertebrate aging remains largely unknown. Here, we use the turquoise killifish ( ) to genetically arrest germline development at discrete stages, and examine how different modes of infertility impact life-history.

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Pituitary hormones play a central role in shaping vertebrate life history events, including growth, reproduction, metabolism, and aging. The regulation of these traits often requires precise control of hormone levels across diverse timescales. However, fine tuning circulating hormones in-vivo has traditionally been experimentally challenging.

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During aging, the loss of metabolic homeostasis drives a myriad of pathologies. A central regulator of cellular energy, the AMP-activated protein kinase (AMPK), orchestrates organismal metabolism. However, direct genetic manipulations of the AMPK complex in mice have, so far, produced detrimental phenotypes.

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The African turquoise killifish has recently gained interest as an emerging vertebrate model system for the study of aging, owing to its naturally short life span and generation time. Here, we provide a step-by-step guide for effective genome engineering using the CRISPR-Cas9 system to generate loss-of-function (i.e.

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Article Synopsis
  • Lymph node stromal cells are essential for lymph node development and immune responses, but their origins and characteristics are not well understood.
  • Using lineage-tracing and single-cell transcriptome analyses, researchers found that most stromal and blood endothelial cells come from Hoxb6 progenitors, while lymphatic endothelial cells are derived from Pax3 progenitors.
  • The study identified various stromal cell subsets in embryonic lymph nodes, suggesting that the diversity of these cells begins early in their development.
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Aging is accompanied by the functional decline of tissues. However, a systematic study of epigenomic and transcriptomic changes across tissues during aging is missing. Here, we generated chromatin maps and transcriptomes from four tissues and one cell type from young, middle-aged, and old mice-yielding 143 high-quality data sets.

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A central challenge in experimental aging research is the lack of short-lived vertebrate models for genetic studies. Here we present a comprehensive protocol for efficient genome engineering in the African turquoise killifish (Nothobranchius furzeri), which is the shortest-lived vertebrate in captivity with a median life span of 4-6 months. By taking advantage of the clustered regularly interspaced short palindromic repeats/CRISPR-associated protein-9 nuclease (CRISPR/Cas9) system and the turquoise killifish genome, this platform enables the generation of knockout alleles via nonhomologous end joining (NHEJ) and knock-in alleles via homology-directed repair (HDR).

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Why and how organisms age remains a mystery, and it defines one of the biggest challenges in biology. Aging is also the primary risk factor for many human pathologies, such as cancer, diabetes, cardiovascular diseases, and neurodegenerative diseases. Thus, manipulating the aging rate and potentially postponing the onset of these devastating diseases could have a tremendous impact on human health.

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Lifespan is a remarkably diverse trait ranging from a few days to several hundred years in nature, but the mechanisms underlying the evolution of lifespan differences remain elusive. Here we de novo assemble a reference genome for the naturally short-lived African turquoise killifish, providing a unique resource for comparative and experimental genomics. The identification of genes under positive selection in this fish reveals potential candidates to explain its compressed lifespan.

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Alternative splicing shapes mammalian transcriptomes, with many RNA molecules undergoing multiple distant alternative splicing events. Comprehensive transcriptome analysis, including analysis of exon co-association in the same molecule, requires deep, long-read sequencing. Here we introduce an RNA sequencing method, synthetic long-read RNA sequencing (SLR-RNA-seq), in which small pools (≤1,000 molecules/pool, ≤1 molecule/gene for most genes) of full-length cDNAs are amplified, fragmented and short-read-sequenced.

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Aging is a complex process that affects multiple organs. Modeling aging and age-related diseases in the lab is challenging because classical vertebrate models have relatively long lifespans. Here, we develop the first platform for rapid exploration of age-dependent traits and diseases in vertebrates, using the naturally short-lived African turquoise killifish.

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The search for developmental mechanisms driving vertebrate organogenesis has paved the way toward a deeper understanding of birth defects. During embryogenesis, parts of the heart and craniofacial muscles arise from pharyngeal mesoderm (PM) progenitors. Here, we reveal a hierarchical regulatory network of a set of transcription factors expressed in the PM that initiates heart and craniofacial organogenesis.

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A fundamental aspect of skeletal myogenesis involves extensive rounds of cell fusion, in which individual myoblasts are incorporated into growing muscle fibers. Here we demonstrate that N-WASp, a ubiquitous nucleation-promoting factor of branched microfilament arrays, is an essential contributor to skeletal muscle-cell fusion in developing mouse embryos. Analysis both in vivo and in primary satellite-cell cultures, shows that disruption of N-WASp function does not interfere with the program of skeletal myogenic differentiation, and does not affect myoblast motility, morphogenesis and attachment capacity.

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In vertebrates, body musculature originates from somites, whereas head muscles originate from the cranial mesoderm. Neck muscles are located in the transition between these regions. We show that the chick occipital lateral plate mesoderm has myogenic capacity and gives rise to large muscles located in the neck and thorax.

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Merkel cells (MCs) are located in the touch-sensitive area of the epidermis and mediate mechanotransduction in the skin. Whether MCs originate from embryonic epidermal or neural crest progenitors has been a matter of intense controversy since their discovery >130 yr ago. In addition, how MCs are maintained during adulthood is currently unknown.

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Adult skeletal muscle possesses a remarkable regenerative capacity, due to the presence of satellite cells, adult muscle stem cells. We used fate-mapping techniques in avian and mouse models to show that trunk (Pax3(+)) and cranial (MesP1(+)) skeletal muscle and satellite cells derive from separate genetic lineages. Similar lineage heterogeneity is seen within the head musculature and satellite cells, due to their shared, heterogenic embryonic origins.

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During embryogenesis, paraxial mesoderm cells contribute skeletal muscle progenitors, whereas cardiac progenitors originate in the lateral splanchnic mesoderm (SpM). Here we focus on a subset of the SpM that contributes to the anterior or secondary heart field (AHF/SHF), and lies adjacent to the cranial paraxial mesoderm (CPM), the precursors for the head musculature. Molecular analyses in chick embryos delineated the boundaries between the CPM, undifferentiated SpM progenitors of the AHF/SHF, and differentiating cardiac cells.

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