Biology subjects

Sweet, C. W.

Publications and source records attributed to Sweet, C. W..

5 recordsLinked to original sources

bioRxiv2026

Transmural Single-Nucleus Transcriptomics Nominates Candidate Disease Programs in Human Necrotizing Enterocolitis

Background & Aims: Necrotizing enterocolitis (NEC) is a life-threatening disease of premature infants marked by inflammation, ischemia, mucosal injury, and, in advanced cases, necrosis extending into deeper layers of the intestinal wall. Because NEC affects specialized, interacting cells in a developing intestine, we used single-nucleus transcriptomics to build a transmural, cell-type-resolved map and nominate hypothesis-generating disease programs distinct from maturation. Methods: Full-thickness intestinal specimens from fetal/prenatal controls, acute NEC cases, and infant controls were analyzed by single-nucleus RNA sequencing (snRNA-seq). Fetal and infant samples served as developmental references. Analyses included cell annotation, NEC-versus-infant differential expression, gene ontology (GO), cross-lineage recurrence, cell death signatures, and developmental maturity. Results: We profiled 53,735 nuclei by snRNA-seq and resolved 34 epithelial, stromal, vascular, immune, neuronal, glial, and smooth muscle populations. We used a morphology-based nuclei scoring system for sample selection that predicted high-quality transcript recovery. NEC nuclei were represented across this cellular landscape, with recurrent gene-expression changes suggesting shared inflammatory recruitment, antimicrobial/redox defense, stress adaptation, complement/vascular activation, reduced homeostatic signaling, and cell death-associated regulation. Developmental maturity analysis identified fetal-like expression levels in subsets of NEC-regulated genes. Proliferative crypt populations retained DNA repair/cell-cycle programs with inflammatory, hypoxic, and ER-stress features, while absorptive enterocytes showed reduced digestive, transport, detoxification, and terminal villus-function programs. Secretory-lineage changes implicated goblet mucus-barrier responses with reduced glycosylation, trafficking, and hydration; enteroendocrine changes in epithelial defense, metabolic stress, and neural signaling; and Paneth cell retention of antimicrobial effector transcripts despite altered ER quality control, autophagy, and granule delivery in NEC. Non-epithelial programs implicated stromal Wnt/BMP niche loss, impaired lymphatic drainage/scavenging, macrophage cytokine activation with reduced clearance machinery, neuroglial circuit defects, and altered smooth muscle contraction-relaxation balance. Conclusions: This single nuclear intestinal cell atlas nominates multicellular programs that may govern NEC initiation, progression toward tissue destruction, and resolution toward functional recovery.

pathology↗

bioRxiv2023

Coordinated differentiation of human intestinal organoids with functional enteric neurons and vasculature

Human intestinal organoids (HIOs) derived from human pluripotent stem cells co-differentiate both epithelial and mesenchymal lineages in vitro but lack important cell types such as neurons, endothelial cells, and smooth muscle. Here, we report an in vitro method to derive HIOs with epithelium, mesenchyme, enteric neuroglial populations, endothelial cells, and organized smooth muscle in a single differentiation, without the need for co-culture. When transplanted into a murine host, these populations expand and organize to support organoid maturation and function. Functional experiments demonstrate enteric nervous system function, with HIOs undergoing peristaltic-like contractions, suggesting the development of a functional neuromuscular unit. HIOs also form functional vasculature, demonstrated in vitro using microfluidic devices to introduce vascular-like flow, and in vivo following transplantation, where HIO endothelial cells anastomose with host vasculature. Collectively, we report an in vitro model of the human gut that simultaneously co-differentiates epithelial, stromal, endothelial, neural, and organized muscle populations.

bioengineering↗

bioRxiv2022

SOX9 elongates cell cycle phases and biases fate decisions in human intestinal stem cells

Background and AimsThe transcription factor SOX9 is expressed in many stem/progenitor cell populations and has biphasic correlations with proliferation rates across different biological systems. In murine intestinal crypts, distinct Sox9 levels mark three phenotypically different cell types, with lowest levels marking rapidly-dividing transit amplifying (TA) cells, intermediate levels marking intestinal stem cells (ISCs), and highest levels marking slowly-dividing label retaining secretory precursors. SOX9 expression levels and the impact of these levels on cell cycle and stem cell activity have not been characterized for humans. MethodsMonolayers of primary human ISCs isolated from healthy organ donors were engineered with stable SOX9-knockout (KO) and/or SOX9-overexpression (OE) genomic modifications to assess the impact of SOX9 levels on proliferative capacity by DNA content analysis, cell cycle phase length by live imaging for a PIP-FUCCI reporter, stem cell activity via organoid formation assays, and cell fate after ISC differentiation tracked via qPCR. ResultsSOX9 was expressed at diverse levels in human intestinal crypt lineages in vivo, repressed proliferation in human ISC monolayers, and predominantly lengthened G1 by >40% with lesser lengthening of S and G2/M phases. Overexpression of SOX9 caused slower proliferation yet increased organoid forming efficiency. Higher SOX9 levels biased ISC differentiation towards tuft cell and follicle-associated epithelium fates while loss of SOX9 biased cells toward absorptive enterocyte, goblet cell, BEST4+ cell, and enteroendocrine cell fates. ConclusionsSOX9 is a master regulator of stem cell activity in human ISCs, lengthening the cell cycle, promoting stemness, and altering differentiation fate. Interestingly, differences are noted between species, highlighting the importance of analyzing regulatory mechanisms in primary healthy human cells.

cell biology↗

bioRxiv2022

A Development-Inspired Niche for Homeostatic Human Mini-Intestines

Epithelial organoids derived from intestinal tissue, also referred to as mini-intestines or mini-guts, recapitulate many aspects of the organ in vitro and can be used for biological discovery, personalized medicine, and drug development. Murine intestinal organoids represent a homeostatic system that balances stem cell maintenance within a crypt-like compartment and differentiation within a villus-like compartment1-3. However, this homeostatic balance and spatial organization has not been achieved with human intestinal organoids4. Here, we leverage single cell RNA-seq data (scRNA-seq) and high-resolution imaging to interrogate the developing human intestinal stem cell niche. We identified an EGF-family member, EPIREGULIN (EREG), as uniquely expressed in the developing crypt, and found that EREG can take the place of EGF as an in vitro niche factor. Unlike EGF, which leads to growth of thin-walled cystic organoids, EREG-organoids are spatially resolved into budded and proliferative crypt domains and a differentiated villus-like central lumen. Transcriptomics and epigenomics showed that EREG-organoids are globally similar to the native intestine while EGF-organoids have an altered chromatin landscape, downregulate the master intestinal transcription factor CDX25,6, and ectopically express stomach genes.

developmental biology↗

bioRxiv2020

Differentiation of human intestinal organoids with endogenous vascular endothelial cells

Human pluripotent stem cell (hPSC)-derived intestinal organoids (HIOs) generated using directed differentiation lack some cellular populations found in the native organ, including vasculature. Using single cell RNA sequencing (scRNAseq), we have identified a transient population of endothelial cells (ECs) present early in HIO differentiation that are lost over time in culture. Here, we have developed a method to enhance co-differentiation and maintenance of ECs within HIOs (vHIOs). Given that ECs are known to possess organ specific gene expression, morphology and function, we used bulk RNAseq and scRNAseq to interrogate the developing human intestine, lung, and kidney in order to identify organ-enriched EC-gene signatures in these organ systems. By comparing organ-specific gene signatures along with markers validated by fluorescent in situ hybridization to HIO ECs, we find that HIO ECs grown in vitro share the highest similarity with native intestinal ECs relative to kidney and lung. Together, these data show that HIOs can co-differentiate a native EC population that are properly patterned with an intestine-specific EC transcriptional signature in vitro.

developmental biology↗