Biology subjects

Quintero, M.

Publications and source records attributed to Quintero, M..

5 recordsLinked to original sources

bioRxiv2026

Paneth cell-derived Notch ligands DLL1 and DLL4 are crucial for intestinal crypt base stem cells.

Notch signaling is essential for maintaining intestinal stem cell activity and directing epithelial cell fate. Paneth cells have been proposed to be niche cells, providing Notch signal to neighboring stem cells through expression of the key Notch ligands DLL1 and DLL4. However, intestinal stem cells persist in the absence of Paneth cells. Here, we used genetic mouse models to clarify the role of Paneth cell-derived Notch ligands for stem cell function. Paneth cell-specific deletion of Dll1 and Dll4 resulted in loss of crypt base stem cells, with no effect on overall crypt cell proliferation. Organoid growth was reduced in knockout mice, suggesting reduced stem cell function. Upon irradiation injury, stem cell return and crypt regeneration were significantly impaired in the Notch ligand-deleted mice. These findings suggest that Paneth cell-derived Notch ligands DLL1 and DLL4 are crucial for crypt base stem cell maintenance and for crypt regeneration after injury.

cell biology↗

bioRxiv2025

Nuclei sense complex tissue shape and direct intestinal stem cell fate

Tissue architecture and function are influenced by mechanical cues. Yet, how cell nuclei sense forces within 3D tissues and dictate differentiation remains unknown as prior studies focused on isolated mesenchymal cells, which fail to fully predict tissue-level mechanical properties. We fill this knowledge gap utilizing live reporters and material-based organoid models. We posit the nucleus as an active mechanosensor of tissue shape, with levels of the nuclear scaffolding protein lamin-A varying across intestinal stem cell differentiation trajectory. Elevated forces on differentiated Paneth cell nuclei, in both organoids and tissue explants, increase lamin-A and nuclear wrinkling. Enhancing nuclear mechanotransduction primes cell differentiation, in otherwise stem promoting conditions, revealing that nuclear mechanics can direct stem cell fate. By engineering spatiotemporally controlled de novo tissue curvature with photo-degradable hydrogels, we direct spatially patterned lamin-A levels across mouse and human organoids of healthy and diseased origin, uncovering conserved nuclear mechanosensing pathway in epithelial tissues.

bioengineering↗

bioRxiv2022

Disruptions in cell fate decisions and transformed enteroendocrine cells drive intestinal tumorigenesis in Drosophila.

Most epithelial tissues are maintained by stem cells that produce the different cell lineages required for proper tissue function. Constant communication between different cell types that make up a tissue is essential to ensure that all cell lineages are produced at appropriate numbers and to mount regenerative responses to injury, infection, and other environmental stresses. Cancer-driving alterations change the intrinsic properties of transformed cells and disrupt stem cell regulation, cell fate decisions, and cell-cell communication within transformed tissue. However, mechanisms by which these processes are disrupted and co-opted to support tumorigenesis are not well understood. Here, we report a novel genetic platform, PromoterSwitch, that allows targeting of genetic manipulations to a small subset of cells of any tissue or cell type of interest and all their subsequent progeny. We use this technology to generate large, transformed clones derived from individual stem/progenitor cells in the adult Drosophila intestine. We show that cancer-driving genetic alterations representing common colon tumor genome landscapes drive disruptions in cell fate decisions within transformed clones and changes in the relative abundance of different intestinal cell lineages. We also uncover a critical, context-dependent role for the differentiated, hormone-producing enteroendocrine (EE) cells in the growth and maintenance of transformed clones. Our analysis in different genetic contexts provides insights into how the intrinsic properties of transformed cells --dictated by the genetic alterations they carry-- determine their response to their environment and dependence on niche signals. A better mechanistic understanding of disruptions of cell-cell communication, stem cell regulation, and cell fate decisions within tumors could reveal novel vulnerabilities and druggable regulatory nodes that can be exploited for therapy. Understanding how tissues respond to the emergence of cells with cancer-driving genetic alterations also provides insights into stem cell biology and epithelial homeostasis.

cancer biology↗

bioRxiv2021

Expression and novel alternative purification of the recombinant nucleocapsid (N) protein of SARS-CoV-2 in Escherichia coli for the serodiagnosis of COVID-19

The SARS-CoV-2 coronavirus causes severe acute respiratory syndrome and has caused a global pandemic by causing the COVID-19 disease. To monitor and control it, diagnostic methods such as molecular and serological tests are necessary. The serological approach uses SARS-CoV-2 antigens to detect the antibodies present in patients using quantitative techniques such as enzyme-linked immunosorbent assay (ELISA) or qualitative rapid tests such as lateral flow chromatography (RDTs). The main antigens used are the spike protein (S) and the nucleocapsid protein (N). Both proteins are obtained in different expression systems, in eukaryotic cells, their production is expensive, so in this work we chose a simpler and cheaper system such as prokaryotic to express and purify the N protein. Thereore, the nucleotide sequence had to being optimized to be expressed in Escherichia coli. The protein N is sensitive to E.coli proteases and also has the ability to self-proteolyze under native conditions, degrading into different fragments. However, under denaturing conditions, using urea and at pH 5.3 it is stable and efficiently purified using metal exchange chromatography (IMAC). In our purification strategy, we surprisingly found that by not using a sonicator, a homogeneous and time-stable preparation of the recombinant antigen is obtained. An approximate yield of 200 mg / L was obtained. It was then tested with healthy sera and sera from COVID-19 convalescent patients in Wester-blot tests that were able to recognize it. Our work provides a novel strategy to produce the SARS-CoV-2 protein N so that it can be used as an input in the development and innovation of serological tests in the diagnosis of COVID-19.

cell biology↗

bioRxiv2020

Vascular-Derived SPARC and SerpinE1 Regulate Interneuron Tangential Migration and Accelerate Functional Maturation of Human Stem Cell-Derived Interneurons

Cortical interneurons establish inhibitory microcircuits throughout the neocortex and their dysfunction has been implicated in epilepsy and neuropsychiatric diseases. Developmentally, interneurons migrate from a distal progenitor domain in order to populate the neocortex - a process that occurs at a slower rate in humans than in mice. In this study, we sought to identify factors that regulate the rate of interneuron maturation across the two species. Using embryonic mouse development as a model system, we found that the process of initiating interneuron migration is regulated by blood vessels of the medial ganglionic eminence (MGE), an interneuron progenitor domain. We identified two endothelial cell-derived paracrine factors, SPARC and SerpinE1, that enhance interneuron migration in mouse MGE explants and organotypic cultures. Moreover, pre-treatment of human stem cell-derived interneurons (hSC-interneurons) with SPARC and SerpinE1 prior to transplantation into neonatal mouse cortex enhanced their migration and morphological elaboration in the host cortex. Further, SPARC and SerpinE1-treated hSC-interneurons also exhibited more mature electrophysiological characteristics compared to controls. Overall, our studies suggest a critical role for CNS vasculature in regulating interneuron developmental maturation in both mice and humans.

neuroscience↗