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Biology subjects

Chen, L.-T.

Publications and source records attributed to Chen, L.-T..

5 recordsLinked to original sources

Endothelin-1 from Tongue Glands Gates 1 Sodium Taste and Intake

Sodium is an essential nutrient. To survive sodium deficiency, animals dramatically increase their appetite for salt. However, whether and how sodium depletion impacts the taste of salt to drive sodium intake is unknown. Here we show that tongue gland-derived endothelin-1 (EDN1) regulates the amiloride-sensitive, sodium-selective salt taste. Edn1 is specifically expressed in the glands embedded within the tongue. Under normal conditions, EDN1 suppresses salt taste by acting on its receptor EDNRB on the projections of salt-sensing taste neurons innervating taste buds. When internal sodium levels drop, EDN1 expression decreases, lifting this inhibition and enhancing responses to salt. Applying EDN1 directly to the tongue, using a nonionic eutectic-based organogel (Neogel) delivery technology that we establish here, dampens the activity of the salt-sensing taste neurons and reduces salt intake and preference. Conversely, genetic deletion of Ednrb in taste neurons mimics the effects of sodium deficiency, enhancing salt-sensing neuron activity and increasing salt consumption. These findings reveal a peripheral mechanism that regulates salt taste and intake in response to internal sodium levels, highlighting a direct role of the taste pathway in maintaining nutrient homeostasis.

neuroscience↗

Spatial multi-omics reveals targetable immunosuppressive macrophage T-cell interactions in human AML bone marrow

The immunosuppressive bone marrow microenvironment is an important contributor to the limited success of immunotherapy in acute myeloid leukemia (AML), but the cellular interactions underlying AML immune evasion are incompletely understood. We therefore generated a single-cell spatial transcriptomic and proteomic atlas using 148 bone biopsies from 113 individuals comprising pediatric and adult AML at diagnosis and non-leukemic controls. We observed an expansion of regulatory T cells (Tregs) in AML, with stronger colocalization between Tregs and macrophages compared to non-leukemic bone marrow. Distinct cellular neighborhoods were enriched for myeloid progenitor-like cells together with macrophages and T cells, which correlated with higher macrophage and T cell immune checkpoint expression. Moreover, these neighborhoods were associated with specific AML subtypes, especially KMT2A-rearranged and RUNX1::RUNX1T1 AML. These spatial patterns were validated by identification of malignant cells via in situ fusion detection in RUNX1::RUNX1T1 cases. Functional experiments revealed that macrophages and AML cells not only actively recruit Tregs, but also promote naive T cell differentiation into Tregs. Spatially informed ligand-receptor analysis predicted the involvement of the Galectin-9 - CD44/TIM-3 axis in this immunosuppressive crosstalk, which was supported by in vitro inhibition of CD44 and/or TIM-3 preventing macrophage- and AML-induced Treg differentiation. Collectively, this comprehensive spatial map of the AML bone marrow identified tripartite crosstalk between AML, macrophages, and T cells mediated by the Galectin-9 - CD44/TIM-3 axis as a key component of the immunosuppressive microenvironment. Targeting Galectin-9 - CD44/TIM-3 interactions may be a promising strategy to overcome immune evasion and enhance immunotherapeutic success in AML. HighlightsO_LISpatial transcriptomic and proteomic atlas of pediatric and adult acute myeloid leukemia (AML) bone marrow C_LIO_LIIncreased colocalization of macrophages and regulatory T cells (Tregs) in AML C_LIO_LIMacrophages and AML cells induce differentiation of naive T cells to Tregs in vitro, which can be prevented by inhibition of CD44 or TIM-3 C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=166 SRC="FIGDIR/small/743431v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@14f313aorg.highwire.dtl.DTLVardef@290bd3org.highwire.dtl.DTLVardef@c749baorg.highwire.dtl.DTLVardef@1b955d0_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

Bacterial cell-free DNA profiling reveals co-elevation of multiple bacteria in newborn foals with suspected sepsis

BackgroundSepsis is the leading cause of death in newborn foals. This study investigates whether cell-free DNA (cfDNA) sequencing can enhance bacterial pathogen detection in foals with suspected sepsis and addresses existing knowledge gaps and diagnostic challenges. MethodsWe developed a foal cfDNA sequencing for bacteria identification (cfFBI) workflow, integrating wetlab and computational protocols to detect increased bacterial cfDNA abundance in blood. Specifically, cfFBI focusses on enriching bacterial cfDNA molecules and preventing false positive bacterial identifications. cfFBI was applied to blood samples of 25 hospitalized foals categorized according to the neonatal Systemic Inflammatory Response Syndrome (nSIRS) criteria and 7 healthy foals. ResultscfDNA levels of potential sepsis-causing bacterial genera were elevated in all 11 nSIRS-positive foals compared to healthy foals (n=7), and in 8/11 (72.7%) when compared to both nSIRS-negative (n=4; nSIRS=0) and healthy foals, with multiple genera elevated in 5/11 (45.5%). The total cfDNA concentration, bacterial cfDNA fraction and bacterial diversity were not different between the foal groups. However, nSIRS-positive foals showed significantly different end-motifs in host chromosomal cfDNA, and a decrease in host mitochondrial cfDNA fraction. ConclusionsThis study is the first to demonstrate that cfDNA sequencing in blood samples from newborn foals enables detection of pathogenic bacteria and can help identify novel host-related sepsis biomarkers. The elevated presence of multiple sepsis-causing genera in nSIRS-positive foals and the difference in end-motif, suggests that multibacterial elevation may be more common than previously thought. These findings indicate that cfDNA sequencing holds promise as a future diagnostic tool for identifying sepsis in newborn foals.

pathology↗

Nanopore-based consensus sequencing enables accurate multimodal tumor cell-free DNA profiling

Shallow genome-wide cell-free DNA (cfDNA) sequencing holds great promise for non-invasive cancer monitoring by providing reliable copy number alteration (CNA) and fragmentomic profiles. Single nucleotide variations (SNVs) are, however, much harder to identify with low sequencing depth due to sequencing errors. Here we present Nanopore Rolling Circle Amplification (RCA)-enhanced Consensus Sequencing (NanoRCS), which leverages RCA and consensus calling based on genome-wide long-read nanopore sequencing to enable simultaneous multimodal tumor fraction estimation through SNVs, CNAs, and fragmentomics. Efficacy of NanoRCS is tested on 18 cancer patient samples and 3 healthy controls, demonstrating its ability to reliably detect tumor fractions as low as 0.24%. In vitro experiments confirm that SNV measurements are essential for detecting tumor fractions below 2%. NanoRCS provides the opportunity for cost-effective and rapid processing, which aligns well with clinical needs, particularly in settings where quick and accurate cancer monitoring is essential for personalized treatment strategies.

genomics↗

Accurate detection of circulating tumor DNA using nanopore consensus sequencing

Levels of circulating tumor DNA (ctDNA) in liquid biopsies may serve as a sensitive biomarker for real-time, minimally-invasive tumor diagnostics and monitoring. However, detecting ctDNA is challenging, as much fewer than 5% of the cell-free DNA in the blood typically originates from the tumor. To detect lowly abundant ctDNA molecules based on somatic variants, extremely sensitive sequencing methods are required. Here, we describe a new technique, CyclomicsSeq, which is based on Oxford Nanopore sequencing of concatenated copies of a single DNA molecule. Consensus calling of the DNA copies increased the base-calling accuracy [~]60x, enabling accurate detection of TP53 mutations at frequencies down to 0.02%. We demonstrate that a TP53-specific CyclomicsSeq assay can be successfully used to monitor tumor burden during treatment for head-and-neck cancer patients. CyclomicsSeq can be applied to any genomic locus and offers an accurate diagnostic liquid biopsy approach that can be implemented in point-of-care clinical workflows.

cancer biology↗