Increased glycolysis and cellular crosstalk in eosinophilic chronic rhinosinusitis with nasal polyps.

Introduction: Chronic rhinosinusitis (CRS) is a chronic inflammatory disease of the sinonasal mucosa with distinct endotypes including type 2 (T2) high eosinophilic CRS with nasal polyps (eCRSwNP), T2 low non-eosinophilic CRS with nasal polyps (neCRSwNP), and CRS without nasal polyps (CRSsNP). Methods: Given the heterogeneity of disease, we hypothesized that assessment of single cell RNA sequencing (scRNA-seq) across this spectrum of disease would reveal connections between infiltrating and activated immune cells and the epithelial and stromal populations that reside in sinonasal tissue. Results: Here we find increased expression of genes encoding glycolytic enzymes in epithelial cells (EpCs), stromal cells, and memory T-cell subsets from patients with eCRSwNP, as compared to healthy controls. In basal EpCs, this is associated with a program of cell motility and Rho GTPase effector expression. Across both stromal and immune subsets, glycolytic programming was associated with extracellular matrix interactions, proteoglycan generation, and collagen formation. Furthermore, we report increased cell-cell interactions between EpCs and stromal/immune cells in eCRSwNP compared to healthy control tissue, and we nominate candidate receptor-ligand pairs that may drive tissue remodeling. Discussion: These findings support a role for glycolytic reprograming in T2-elicited tissue remodeling and implicate increased cellular crosstalk in eCRSwNP.

Rhinovirus infection of airway epithelial cells uncovers the non-ciliated subset as a likely driver of genetic susceptibility to childhood-onset asthma.

Asthma is a complex disease caused by genetic and environmental factors. Epidemiological studies have shown that in children, wheezing during rhinovirus infection (a cause of the common cold) is associated with asthma development during childhood. This has led scientists to hypothesize there could be a causal relationship between rhinovirus infection and asthma or that RV-induced wheezing identifies individuals at increased risk for asthma development. However, not all children who wheeze when they have a cold develop asthma. Genome-wide association studies (GWAS) have identified hundreds of genetic variants contributing to asthma susceptibility, with the vast majority of likely causal variants being non-coding. Integrative analyses with transcriptomic and epigenomic datasets have indicated that T cells drive asthma risk, which has been supported by mouse studies. However, the datasets ascertained in these integrative analyses lack airway epithelial cells. Furthermore, large-scale transcriptomic T cell studies have not identified the regulatory effects of most non-coding risk variants in asthma GWAS, indicating there could be additional cell types harboring these "missing regulatory effects". Given that airway epithelial cells are the first line of defense against rhinovirus, we hypothesized they could be mediators of genetic susceptibility to asthma. Here we integrate GWAS data with transcriptomic datasets of airway epithelial cells subject to stimuli that could induce activation states relevant to asthma. We demonstrate that epithelial cultures infected with rhinovirus significantly upregulate childhood-onset asthma-associated genes. We show that this upregulation occurs specifically in non-ciliated epithelial cells. This enrichment for genes in asthma risk loci, or 'asthma heritability enrichment' is also significant for epithelial genes upregulated with influenza infection, but not with SARS-CoV-2 infection or cytokine activation. Additionally, cells from patients with asthma showed a stronger heritability enrichment compared to cells from healthy individuals. Overall, our results suggest that rhinovirus infection is an environmental factor that interacts with genetic risk factors through non-ciliated airway epithelial cells to drive childhood-onset asthma.

Development of a Pipeline for Removing Allergy Labels in Patients Undergoing Hematopoietic Stem Cell Transplantation.

Penicillin allergy is reported by 10% to 20 % of patients, but when evaluated only 1% to 2% may have a true allergy. Patients undergoing hematopoietic stem cell transplantation (HSCT) have a high likelihood of requiring beta-lactam antibiotics due to increased infection risk, which can be limited by a penicillin allergy label. When a penicillin allergy is recorded, alternatives are needed, including more expensive broader-spectrum antibiotics, with increases in drug-resistant bacteria, longer hospital stays, higher expenditures, and increases in nosocomial infections, such as Clostridium difficile colitis. This group of patients already undergoes extensive pretreatment testing and would especially benefit from allergy delabeling. This study aimed to develop a self-sustaining, low-cost pipeline between an HSCT clinic and an allergy clinic to identify and successfully delabel low-risk patients who endorse an allergy to penicillin, amoxicillin, amoxicillin-clavulanate, piperacillin-tazobactam, or ampicillin before admission to the hospital. We developed a survey to triage allergy risk, identified key stakeholders in building the pipeline, and underwent 4 plan, do, study, act (PDSA) cycles. Changes were made in each of the PDSA cycles to minimize cost and uncompensated provider time, as well as to increase patient retention throughout the pipeline by increasing appointment availability and decreasing reliance on patients to independently progress through the pathway. Of the 410 patients with planned HSCT who were screened over 11 months, 89 (21.7%) were listed as having a penicillin and/or beta lactam allergy. All but 1 (66 of 67; 98.5%) of the participants completed the survey accurately when confirmed by an allergist, and the survey was 100% accurate in predicting delabeling success in low-risk patients. Of eligible patients, 43.8% (n = 39) were successfully delabeled before their transplant date, and 97.4% of these (n = 38) have undergone HSCT to date. This pipeline is maintained by approximately 5 hours of work per week (1 hour of allergy physician time, 4 hours of nurse and/or clinical coordinator time), with no other direct costs. There is an estimated direct savings of at least $1914.93 per patient delabeled. We successfully designed and implemented a pipeline between the HSCT clinic and the allergy clinic as a quality improvement initiative to identify and address high rates of reported beta-lactam allergies. We identified and addressed patient-based factors, logistical, temporal, and financial barriers that impacted patient retention and sustainability. This model is expected to yield significant and sustained cost savings for the healthcare system as well as to improve patient outcomes, and this hypothesis is currently undergoing formal analysis. We anticipate that this model can be used to create a similar pipeline in other healthcare systems for HSCT recipients, as well as patients in other clinical settings, such as oncology and chimeric antigen receptor T cell therapy.

Increased epithelial mTORC1 activity in chronic rhinosinusitis with nasal polyps.

Background: The airway epithelium plays a central role in the pathogenesis of chronic respiratory diseases such as asthma and chronic rhinosinusitis with nasal polyps (CRSwNP), but the mechanisms by which airway epithelial cells (EpCs) maintain inflammation are poorly understood. Objective: We hypothesized that transcriptomic assessment of sorted airway EpCs across the spectrum of differentiation would allow us to define mechanisms by which EpCs perpetuate airway inflammation. Methods: Ethmoid sinus EpCs from adult patients with CRS were sorted into 3 subsets, bulk RNA sequenced, and analyzed for differentially expressed genes and pathways. Single cell RNA-seq (scRNA-seq) datasets from eosinophilic and non-eosinophilic CRSwNP and bulk RNA-seq of EpCs from mild/moderate and severe asthma were assessed. Immunofluorescent staining and ex vivo functional analysis of sinus EpCs were used to validate our findings. Results: Analysis within and across purified EpC subsets revealed an enrichment in glycolytic programming in CRSwNP vs CRSsNP. Correlation analysis identified mammalian target of rapamycin complex 1 (mTORC1) as a potential regulator of the glycolytic program and identified EpC expression of cytokines and wound healing genes as potential sequelae. mTORC1 activity was upregulated in CRSwNP, and ex vivo inhibition demonstrated that mTOR is critical for EpC generation of CXCL8, IL-33, and CXCL2. Across patient samples, the degree of glycolytic activity was associated with T2 inflammation in CRSwNP, and with both T2 and non-T2 inflammation in severe asthma. Conclusions: Together, these findings highlight a metabolic axis required to support epithelial generation of cytokines critical to both chronic T2 and non-T2 inflammation in CRSwNP and asthma.

Impairment of an Endothelial NAD+-H2S Signaling Network Is a Reversible Cause of Vascular Aging.

A decline in capillary density and blood flow with age is a major cause of mortality and morbidity. Understanding why this occurs is key to future gains in human health. NAD precursors reverse aspects of aging, in part, by activating sirtuin deacylases (SIRT1-SIRT7) that mediate the benefits of exercise and dietary restriction (DR). We show that SIRT1 in endothelial cells is a key mediator of pro-angiogenic signals secreted from myocytes. Treatment of mice with the NAD+ booster nicotinamide mononucleotide (NMN) improves blood flow and increases endurance in elderly mice by promoting SIRT1-dependent increases in capillary density, an effect augmented by exercise or increasing the levels of hydrogen sulfide (H2S), a DR mimetic and regulator of endothelial NAD+ levels. These findings have implications for improving blood flow to organs and tissues, increasing human performance, and reestablishing a virtuous cycle of mobility in the elderly.

Modeling and Validation of Multilayer Poly(Lactide-Co-Glycolide) Scaffolds for In Vitro Directed Differentiation of Juxtaposed Cartilage and Bone.

Polymeric scaffolds, which release growth factors in a temporally controlled manner, have successfully directed the differentiation of stem cells into monolithic tissues of a single lineage. However, engineering precise boundaries in multilineage functional tissues, such as the juxtaposed cartilaginous and osseous tissue present in articulated joints, often remains a challenge. This work demonstrates a precise materials system for in vitro reconstruction of the three-dimensional architecture of these types of human tissues. Multilayer poly(lactide-co-glycolide) (PLG) scaffolds were used to produce spatiotemporal gradients to direct the differentiation of an initially uniform population of mesenchymal stem cells (MSCs) into juxtaposed cartilage and bone. Specifically, growth factors (chondrogenic transforming growth factor-ß3 and osteogenic bone morphogenetic protein-4) and their neutralizing antibodies were incorporated within distinct layers of the PLG scaffolds to create spatially segregated morphogen fields within the scaffold volume. The multilayer PLG scaffold designs were optimized by mathematical modeling, and generation of spatially segregated morphogen gradients was validated by assessing activity of luciferase reporter cell lines responsive to each growth factor. Scaffolds seeded with MSCs demonstrated production of juxtaposed cartilage and bone, as evaluated by biochemical staining and western blotting for tissue-specific matrix proteins. This work demonstrates a significant advance for the engineering of implantable constructs comprising tissues of multiple lineages, with potential applications in orthopedic regenerative medicine.

Photoactivation of endogenous latent transforming growth factor-ß1 directs dental stem cell differentiation for regeneration.

Rapid advancements in the field of stem cell biology have led to many current efforts to exploit stem cells as therapeutic agents in regenerative medicine. However, current ex vivo cell manipulations common to most regenerative approaches create a variety of technical and regulatory hurdles to their clinical translation, and even simpler approaches that use exogenous factors to differentiate tissue-resident stem cells carry significant off-target side effects. We show that non-ionizing, low-power laser (LPL) treatment can instead be used as a minimally invasive tool to activate an endogenous latent growth factor complex, transforming growth factor-ß1 (TGF-ß1), that subsequently differentiates host stem cells to promote tissue regeneration. LPL treatment induced reactive oxygen species (ROS) in a dose-dependent manner, which, in turn, activated latent TGF-ß1 (LTGF-ß1) via a specific methionine residue (at position 253 on LAP). Laser-activated TGF-ß1 was capable of differentiating human dental stem cells in vitro. Further, an in vivo pulp capping model in rat teeth demonstrated significant increase in dentin regeneration after LPL treatment. These in vivo effects were abrogated in TGF-ß receptor II (TGF-ßRII) conditional knockout (DSPP(Cre)TGF-ßRII(fl/fl)) mice or when wild-type mice were given a TGF-ßRI inhibitor. These findings indicate a pivotal role for TGF-ß in mediating LPL-induced dental tissue regeneration. More broadly, this work outlines a mechanistic basis for harnessing resident stem cells with a light-activated endogenous cue for clinical regenerative applications.