Biology subjects

Hatch, C. J.

Publications and source records attributed to Hatch, C. J..

5 recordsLinked to original sources

bioRxiv2026

An Ovol1 Variant in Endothelial Cells Regulates Slug and is Essential for Pathological Angiogenesis

During development, the blood vasculature expands by sprouting angiogenesis, but the programs that guide this process can become dysregulated in the pathological angiogenesis of neovascular diseases leading to excessive disorganized blood vessels. We previously reported that in endothelial cells, the pro-mesenchymal transcription factor Slug critically regulates angiogenesis through a partial and reversible endothelial-to-mesenchymal transition (pEndoMT); however, the upstream regulators that activate Slug and may contribute to pathological activation of the pEndoMT pathway in disease are still poorly understood. Here, we show that endothelial cells express an unusual low molecular weight variant of Ovol1 - a zinc-finger transcription factor that regulates mesenchymal transition in epithelial cells. Ovol1 and Slug are co-expressed in angiogenic endothelial cells, and using ChIP, we confirm direct Ovol1 binding to the endogenous Slug gene at a species-conserved binding motif. Whereas Ovol1 is typically a transcriptional repressor in epithelial cells, we find using a combination of silencing RNA and lentiviral overexpression constructs that the endothelial Ovol1 variant upregulates Slug, and is sufficient to drive pEndoMT marker expression and enhance endothelial cell migratory capacity. Silencing of Ovol1 abolished sprouting angiogenesis in a 3D in vitro sprouting angiogenesis assay, whereas constitutive overexpression of Ovol1 produced overaggressive and disorganized hypersprouting that depends upon Slug. We generated Ovol1 or Slug endothelial-specific knockout mice (Ovol1ECKO and SlugECKO) and found that healthy developmental angiogenesis of the neonatal mouse retina proceeds relatively normally in knockout animals. By contrast, Ovol1 was reduced in established post-natal blood vessels but became strongly re-expressed in tumor endothelial cells, and we found that colorectal cancer syngraft growth was significantly reduced in both Ovol1ECKO and SlugECKO mice alongside a failure of tumor angiogenesis. Lastly, neovascularization in the oxygen-induced retinopathy (OIR) model was also reduced in SlugECKO mice. In conclusion, we report that an endothelial Ovol1 variant upregulates Slug and drives a mesenchymal-like state, and that this Ovol1-Slug pEndoMT signaling axis is essential for pathological angiogenesis in neovascular disease models.

cell biology↗

bioRxiv2025

Methods for Processing and Analyzing Images of Vascularized Micro-Organ and Tumor Systems

Our group has developed and validated an advanced microfluidic platform to improve preclinical modeling of healthy and disease states, enabling extended culture and detailed analysis of tissue-engineered miniaturized organ constructs, or "organs-on-chips." Within this system, diverse cell types self-organize into perfused microvascular networks under dynamic flow within tissue chambers, effectively mimicking the structure and function of native tissues. This setup facilitates physiological intravascular delivery of nutrients, immune cells, and therapeutic agents, and creates a realistic microenvironment to study cellular interactions and tissue responses. Known as the vascularized micro-organ (VMO), this adaptable platform can be customized to represent various organ systems or tumors, forming a vascularized micro-tumor (VMT) for cancer studies. The VMO/VMT system closely simulates in vivo nutrient exchange and drug delivery within a 3D microenvironment, establishing a high-fidelity model for drug screening and mechanistic studies in vascular biology, cancer, and organ-specific pathologies. Furthermore, the optical transparency of the device supports high-resolution, real-time imaging of fluorescently labeled cells and molecules within the tissue construct, providing key insights into drug responses, cell interactions, and dynamic processes such as epithelial-mesenchymal transition. To manage the extensive imaging data generated, we created standardized, high-throughput workflows for image analysis. This manuscript presents our image processing and analysis pipeline, utilizing a suite of tools in Fiji/ImageJ to streamline data extraction from the VMO/VMT model, substantially reducing manual processing time. Additionally, we demonstrate how these tools can be adapted for analyzing imaging data from traditional in vitro models and microphysiological systems developed by other researchers.

bioengineering↗

bioRxiv2024

A Microphysiological HHT-on-a-Chip Platform Recapitulates Patient Vascular Lesions

Hereditary Hemorrhagic Telangiectasia (HHT) is a rare congenital disease in which fragile vascular malformations focally develop in multiple organs. These can be small (telangiectasias) or large (arteriovenous malformations, AVMs) and may rupture leading to frequent, uncontrolled bleeding. There are few treatment options and no cure for HHT. Most HHT patients are heterozygous for loss-of-function mutations for Endoglin (ENG) or Alk1 (ACVRL1), however, why loss of these genes manifests as vascular malformations remains poorly understood. To complement ongoing work in animal models, we have developed a microphysiological system model of HHT. Based on our existing vessel-on-a-chip (VMO) platform, our fully human cell-based HHT-VMO recapitulates HHT patient vascular lesions. Using inducible ACVRL1 (Alk1)-knockdown, we control timing and extent of endogenous Alk1 expression in primary human endothelial cells (EC) in the HHT-VMO. HHT-VMO vascular lesions develop over several days, and are dependent upon timing of Alk1 knockdown. Interestingly, in chimera experiments AVM-like lesions can be comprised of both Alk1-intact and Alk1-deficient EC, suggesting possible cell non-autonomous effects. Single cell RNA sequencing data are consistent with microvessel pruning/regression as contributing to AVM formation, while loss of PDGFB expression implicates mural cell recruitment. Finally, lesion formation is blocked by the VEGFR inhibitor pazopanib, mirroring the positive effects of this drug in patients. In summary, we have developed a novel HHT-on-a-chip model that faithfully reproduces HHT patient lesions and that is sensitive to a treatment effective in patients. The VMO-HHT can be used to better understand HHT disease biology and identify potential new HHT drugs. SignificanceThis manuscript describes development of an organ-on-a-chip model of Hereditary Hemorrhagic Telangiectasia (HHT), a rare genetic disease involving development of vascular malformations. Our VMO-HHT model produces vascular malformations similar to those seen in human HHT patients, including small (telangiectasias) and large (arteriovenous malformations) lesions. We show that VMO-HHT lesions are sensitive to a drug, pazopanib, that appears to be effective in HHT human patients. We further use the VMO-HHT platform to demonstrate that there is a critical window during vessel formation in which the HHT gene, Alk1, is required to prevent vascular malformation. Lastly, we show that lesions in the VMO-HHT model are comprised of both Alk1-deficient and Alk1-intact endothelial cells.

cell biology↗

bioRxiv2023

Targeting tumor-stromal interactions in triple-negative breast cancer using a human vascularized micro-tumor model

Triple-negative breast cancer (TNBC) is highly aggressive with limited available treatments. Stromal cells in the tumor microenvironment (TME) are crucial in TNBC progression; however, understanding the molecular basis of stromal cell activation and tumor-stromal crosstalk in TNBC is limited. To investigate therapeutic targets in the TNBC stromal niche, we used an advanced human in vitro microphysiological system called the vascularized micro-tumor (VMT). Using single-cell RNA sequencing (scRNA-seq), we revealed that normal breast-tissue stromal cells activate neoplastic signaling pathways in the TNBC TME. By comparing interactions in VMTs with clinical data, we identified therapeutic targets at the tumor-stromal interface with potential clinical significance. Combining treatments targeting Tie2 signaling with paclitaxel resulted in vessel normalization and increased efficacy of paclitaxel in the TNBC VMT. Dual inhibition of Her3 and Akt also demonstrated efficacy against TNBC. These data demonstrate the potential of inducing a favorable TME as a targeted therapeutic approach in TNBC.

cancer biology↗

bioRxiv2022

Engineered vasculature induces functional maturation of pluripotent stem cell-derived islet organoids

Blood vessels play a critical role in pancreatic islet health and function, yet current culture methods to generate islet organoids from human pluripotent stem cells (SC-islets) lack a vascular component. Here, we engineered 3D vascularized SC-islet organoids by assembling SC-islet cells, human primary endothelial cells (ECs) and fibroblasts both in a non-perfused model and a microfluidic device with perfused vessels. Vasculature improved stimulus-dependent Ca2+ influx into SC-{beta}-cells, a hallmark of {beta}-cell function that is blunted in non-vascularized SC-islets. We show that an islet-like basement membrane is formed by vasculature and contributes to the functional improvement of SC-{beta}-cells. Furthermore, cell-cell communication networks based on scRNA-seq data predicted BMP2/4-BMPR2 signaling from ECs to SC-{beta}-cells. Correspondingly, BMP4 augmented the SC-{beta}-cell Ca2+ response and insulin secretion. These vascularized SC-islet models will enable further studies of crosstalk between {beta}-cells and ECs and can serve as in vivo-mimicking platforms for disease modeling and therapeutic testing.

cell biology↗