Wu, Q. C. | bioRxiv Science

bioRxiv2024

IL-17A primes an early progenitor compartment to tune the erythropoietic feedback circuit

Feedback control of erythropoiesis exemplifies conflicting goals in tissue homeostasis: maintaining fast reactivity to stress while minimizing proliferative burden on progenitors in the steady state. Here we show that these conflicting goals are tuned through the combinatorial action of cytokines. We find that IL-17A, a pro-inflammatory cytokine, mediates striking synergism with the negative feedback signal erythropoietin (Epo) in vivo, accelerating the erythropoietic response to hypoxia. A model of erythropoietic control shows increased reactivity may occur through two cell circuit designs, with one having far lower constitutive progenitor burden in normoxia. IL-17A acts through this optimal design by sensitizing progenitors to Epo, a model supported by multiple experimental observations. We suggest that IL-17A signals impending hypoxia during infections, tuning erythropoiesis in favor of a faster stress response. Our study highlights IL-17A as a potential erythropoietic therapeutic agent and serves as a model of homeostatic tuning in stem and progenitor cell circuits.

systems biology↗

bioRxiv2018

A Toolkit for Rapid Modular Construction of Biological Circuits in Mammalian Cells

The ability to rapidly assemble and prototype cellular circuits is vital for biological research and its applications in biotechnology and medicine. Current methods that permit the assembly of DNA circuits in mammalian cells are laborious, slow, expensive and mostly not permissive of rapid prototyping of constructs. Here we present the Mammalian ToolKit (MTK), a Golden Gate-based cloning toolkit for fast, reproducible and versatile assembly of large DNA vectors and their implementation in mammalian models. The MTK consists of a curated library of characterized, modular parts that can be easily mixed and matched to combinatorially assemble one transcriptional unit with different characteristics, or a hierarchy of transcriptional units weaved into complex circuits. MTK renders many cell engineering operations facile, as showcased by our ability to use the toolkit to generate single-integration landing pads, to create and deliver libraries of protein variants and sgRNAs, and to iterate through Cas9-based prototype circuits. As a biological proof of concept, we used the MTK to successfully design and rapidly construct in mammalian cells a challenging multicistronic circuit encoding the Ebola virus (EBOV) replication complex. This construct provides a non-infectious biosafety level 2 (BSL2) cellular assay for exploring the transcription and replication steps of the EBOV viral life cycle in its host. Its construction also demonstrates how the MTK can enable important and time sensitive applications such as the rapid testing of pharmacological inhibitors of emerging BSL4 viruses that pose a major threat to human health.

synthetic biology↗