Biology subjects

Monroy, I.

Publications and source records attributed to Monroy, I..

3 recordsLinked to original sources

bioRxiv2025

Extracorporeal Placental Support in a Sheep's Gravid Uterus

BACKGROUNDThe placenta is a vital organ in animal development, yet its function is understudied. Existing ex vivo placental support models study the organ in isolation, without the uterus and fetus. We report our early experience with a novel model of extracorporeal placental support by perfusing a sheeps gravid uterus. METHODSA sheep gravid hysterectomy was performed after cannulating the uterine vessels. The isolated uterus was maintained in a warm crystalloid tank. Oxygenation, electrolyte supplementation, and glucose were provided through an extracorporeal life support circuit, while monitoring the fetal heart rate and pressure. Our primary objective was to establish the feasibility of the model, confirm the ability to transition the organ to ex vivo support (fetal survival for >30 minutes after hysterectomy), and measure the duration of fetal survival after uterine explantation. RESULTSA total of 51 surgeries were performed, and 76% were successfully transitioned to extracorporeal support. Growing experience throughout the study period led to technical adaptations and more prolonged survival. Uteri with a singleton fetus had longer mean survival times, when compared to twins (253 minutes vs. 104 minutes, p=.019). Anemia and coagulopathy were frequently encountered, and most of the uteri had significant clot formation around the placentomes at the end of the experiment. CONCLUSIONUsing a model of extracorporeal placental support in sheep, we were able to maintain a live fetus within the uterus for more than 16 hours after hysterectomy. This technique is feasible and could provide an avenue to study fetoplacental physiology in an ex vivo environment.

physiology↗

bioRxiv2021

A reservoir of stem-like CD8 T cells in the tumor-draining lymph node maintains the ongoing anti-tumor immune response

"Stem-like" TCF1+ CD8+ T cells (TSL) are necessary for long-term maintenance of T cell responses and the efficacy of immunotherapy but, as tumors contain signals that should drive T-cell terminal-differentiation, how these cells are maintained in tumors remains unclear. We found that a small number of TCF1+ tumor-specific CD8+ T cells were present in tumors throughout development. Yet, most intratumoral T cells differentiated as tumors progressed, corresponding with an immunologic shift in the tumor microenvironment (TME) from "hot" to "cold". By contrast, most tumor-specific CD8+ T cells in tumor-draining lymph nodes (dLNs) had functions and gene expression signatures similar to TSL from chronic LCMV infection and this population was stable over time, despite the changes in the TME. dLN T cells were the precursors of their more-differentiated intratumoral counterparts, and maintenance of TCF1 by intratumoral T cells required continuous migration from dLNs. Finally, TSL CD8 T cells were also present in LNs from lung adenocarcinoma patients, suggesting this population is also relevant in human disease. Thus, we propose that the dLN TSL reservoir has a critical function during tumor development in sustaining antitumor T cells during tumor development and protecting them from the terminal differentiation that occurs in the TME.

immunology↗

bioRxiv2020

NINJA: an inducible genetic model for creating neoantigens in vivo

Mouse models with inducible neoantigens have been historically difficult to generate because of leaky expression of antigens in the thymus, which causes central tolerance in developing CD8 and CD4 T cells. Attempts to resolve this problem using existing genetic tools have been unsuccessful. We developed the iNversion INducible Joined neoAntigen (NINJA) mouse model that uses RNA splicing, DNA recombination, and three levels of regulation to prevent neoantigen leakiness and allow tight control over the induction of neoantigen expression. We describe the development of these genetic tools and their use for obtaining tumor cell lines with inducible neoantigen expression. Moreover, we show that the genetic regulation in NINJA mice bypasses central and peripheral tolerance mechanisms and allows for robust endogenous CD8 and CD4 T cells responses upon neoantigen induction in peripheral tissues. Thus, NINJA fills a long-standing gap in the field and will enable studies of how T cells respond to defined neoantigens in the context of peripheral tolerance, autoimmune diseases, and developing tumors.

immunology↗