Laurie Pryde Shornick

The prevalence of obesity among adults of childbearing age has tripled worldwide since 1975. Obesity during pregnancy has been linked to impaired neonatal immunity and a higher risk of infections in childhood but the causal mechanisms have not been defined. Using a mouse model of diet-induced obesity, we documented impaired antiviral immunity in the offspring of obese mice, corresponding with reduced cell-mediated immune responses. This included lower frequencies of Tbet+ CD4+ T helper 1 cells and a decrease in cytotoxic CD8+ T cells in the lungs of mice infected with respiratory Sendai virus, and confirmed in spleens from mice infected with LCMV. Consistent with impaired cellular immunity, single-cell transcriptomic analysis of bone marrow revealed altered hematopoiesis in these offspring, with evidence of interferon-induced skewing toward myelopoiesis at the expense of lymphocyte development. Our studies provide an in-depth transcriptomic profile of immune cell progenitors in the bone marrow paired with mature innate and adaptive immune cell populations in lymph nodes at single-cell resolution. Results suggest that compromised immune protection from viral infections in the offspring of obese mice stems from altered lymphocyte development that is influenced by inflammatory interferon signaling in bone marrow.

Introduction: Bacterial infection and biofilm formation contribute to impaired healing in chronic diabetic wounds. Staphylococcus aureus and Pseudomonas aeruginosa are found in human diabetic wound biofilms. They may develop antibiotic resistance, increasing the urgency for alternative or complementary therapies. Diabetic wound healing may be improved with the use of biomedically engineered scaffolds, which can also serve as delivery systems for antibacterial compounds. Manuka honey is a potent antibacterial and wound care agent due to its high osmolarity, low pH, and constituents (such as methylglyoxal). Honey exhibits bacteriostatic and bactericidal effects, modulates the expression of biofilm forming genes, and restores antibiotic susceptibility in previously drug resistant pathogens.Methods: In this study, we created a dermal regeneration template (DRT) composed of polycaprolactone-gelatin (PCL-gelatin) and Manuka honey to retain honey in the wound and also provide a scaffold for tissue regeneration.Results and discussion: Soluble Manuka honey inhibited the planktonic and biofilm growth of both S. aureus (UWH3) and P. aeruginosa (PA14) co-cultures. Manuka honey embedded PCL-gelatin scaffolds did not exhibit bacteriostatic or bactericidal effects on cocultures of UHW3 and PA14; however, they promoted the expression of AgrA, a gene associated with dispersal of S. aureus biofilms.

Epithelial barrier cells are proposed to be critical for host defense, and airway epithelial cell capacity for IFN signal transduction is presumed to protect against respiratory viral infection. However, it has been difficult to fully test these concepts given the absence of tools to analyze IFN signaling specific to airway epithelial cells in vivo. To address these issues, we generated a new line of transgenic mice with Cre-driver genes (Foxj1 and Scgb1a1) for a floxed-Stat1 allele (designated Foxj1-Scgb1a1-Cre-Stat1f/f mice) to target the master IFN signal regulator STAT1 in airway epithelial cells and tested these mice for control of infection because of mouse parainfluenza (Sendai) virus and human enterovirus D68 (EV-D68). Indeed, both types of infections showed increases in viral titers and severity of acute illness in Foxj1-Scgb1a1-Cre-Stat1f/f mice and conventional Stat1−/− mice compared with wild-type mice. In concert, the chronic lung disease that develops after Sendai virus infection was also increased in Foxj1-Scgb1a1-Cre-Stat1f/f and Stat1–/– mice, marked by airway and adjacent parenchymal immune cell infiltration and mucus production for at least 7 wk postinfection. Unexpectedly, relatively mild EV-D68 infection also progressed to chronic lung disease in Foxj1-Scgb1a1-Cre-Stat1f/f and Stat1−/− mice but was limited (like viral replication) to airways. The results thereby provide proof-of-concept for a critical role of barrier epithelial cells in protection from acute illness and chronic disease after viral infection and suggest a specific role for airway epithelial cells given the limitation of EV-D68 replication and acute and chronic manifestations of disease primarily to airway tissue.

Manuka honey is an ancient remedy to improve wound healing; however, an effective delivery system is needed to facilitate extended release of honey into wounds. We developed an electrospun dermal regeneration template consisting of a poly (ε‐caprolactone) (PCL) scaffold embedded with 1%, 5%, 10%, or 20% manuka honey. In vitro studies demonstrated that honey PCL scaffolds were not toxic to macrophages, and they allowed for macrophage infiltration into the scaffolds. Vascular endothelial growth factor (VEGF), a marker of angiogenesis, was released by macrophages cultured with scaffolds and macrophage/scaffold conditioned media promoted endothelial cell tube formation in an angiogenesis assay. In a full thickness murine wound model, the scaffolds prevented rapid wound contraction. In vivo, cells infiltrated the scaffolds by post‐wounding day 7, but the honey scaffolds did not affect collagen deposition at that time. In summary, preliminary studies investigating the effect of honey on tissue repair show that scaffolds prevent rapid wound contraction, allow for cell infiltration, and promote angiogenesis. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B:2620–2628, 2019.

During respiratory viral infection, conventional dendritic cells (cDCs) take up antigen and migrate to the draining lymph nodes to present viral antigen and activate cytotoxic T lymphocytes; however, regulation of cDC activation and migration may be age dependent. In this study, we used a mouse model of paramyxoviral infection (Sendai virus) and demonstrated that cDCs, which have migrated from lungs to the draining lymph nodes, are delayed in expressing activation markers in neonatal mice compared with adults. Neonatal lung cDCs expressed reduced levels of MHC Class II (major histocompatibility complex II) and CCR7 (chemokine receptor type 7) on postinfection days 3 and 5, respectively. The level of the CCR7 ligand CCL19 was significantly reduced in neonatal lungs during the course of viral infection. Interestingly, the arachidonic acid metabolite prostaglandin D ₂ (PGD ₂ ) was present at significantly higher levels in neonatal bronchoalveolar lavage fluid compared with adults. This was associated with increased expression of lipocalin PGD ₂ synthase mRNA levels in neonatal lungs and in isolated neonatal tracheal epithelial cells. Although thymic stromal lymphopoietin (TSLP) expression has been associated with increased PGD ₂ production, we found that TSLP levels were reduced in neonatal lungs. Importantly, blocking PGD ₂ function using a prostaglandin D ₂ receptor 1 (DP1) antagonist restored cDC activation in neonates. Together, these data suggest that cDC activation in neonates is delayed by a PGD ₂ mechanism and associated decreased chemokine signals.

A primary aim in wound-healing research is to construct an inexpensive, biodegradable dermal regeneration template with heightened moisture retention and permeability properties. The presence of moisture is important for optimal burn wound healing as it creates an environment for re-epithelialization and minimizes the risk of infections. Permeability can be achieved through a process known as electrospinning. This scaffold fabrication technique creates a mat of randomly oriented nanofibers that can readily mimic native extracellular matrix. Novel electrospun silk fibroin scaffolds were fabricated with poloxamer 407 (P407) and Manuka honey additives for a burn wound dermal regeneration template application. Enhanced human dermal fibroblast adhesion and cell infiltration were observed with the inclusion of P407, and scaffolds incorporated with Manuka honey demonstrated increased water uptake and a higher cell density within the scaffolds at the end of a 28-day period. Overall, this study established that both the silk fibroin/P407 and silk fibroin/Manuka honey scaffolds have the potential to be successful dermal regeneration templates, with P407 increasing surface wettability and Manuka honey modulating moisture retention.

Objective: Impaired wound healing in diabetic (DB) patients is a significant health problem; however, the roles that cytokines and innate immune cells contribute to this impaired healing are not completely understood. Approach: A mouse model was used to compare the innate immune response during DB and normal wound healing. Two 5-mm full-thickness wounds were created on the dorsal skin of BKS.Cg-m+/+Leprdb/J (DB) and C57BL/6 (wild-type) mice. Innate immune cell markers and cytokine mRNA levels were measured in wound biopsies during the first week of healing. Results: Innate immune cell influx (typified by the Gr-1 neutrophil marker and the Ym1 macrophage marker) was delayed in the DB wounds. Expression of the M2 macrophage-related genes, Ym1 and arginase 1, was significantly reduced in the DB wounds. PCR array analysis demonstrated altered cytokine expression in DB wounds. Most prominently, both interleukin (IL)-17 and IL-20 mRNA levels were significantly increased in the DB wounds. Innovation: This is the first study to identify increased levels of IL-17 and IL-20 in DB wounds. These cytokines are also elevated in the inflammatory skin disorder, psoriasis; thus, they may be potential therapeutic targets to aid in DB wound healing. Conclusion: The entire cytokine profile of DB wounds over the course of healing is not completely understood. This study suggests that the IL-17 and IL-20 families of cytokines should be further analyzed in the context of DB wound healing.

Chorioamnionitis, an inflammatory gestational disorder, commonly precedes preterm delivery. Preterm infants may be at particular risk for inflammation-related morbidity related to infection, although the pathogenic mechanisms are unclear. We hypothesized that maternal inflammation modulates immune programming to drive postnatal inflammatory processes.

Introduction. Silver dressings are widely used in the treatment of chronic wounds to reduce bacterial bioburden. However, little is known about the mechanism of silver ions on the healing process. In this study, a mouse model of wound healing was used to examine the effect of silver dressings in normal and diabetic wounds. Two 5-mm full-thickness wounds were created on the dorsal skin of diabetic BKS.Cg- m+/+Leprdb/J mice (experimental group) and wild type C57BL/6 mice (control group), and treated with either a silver or gauze dressing. Measurement of wound areas by digital planimetry demonstrated faster healing in the silver-treated wounds of both diabetic and control mice. Quantitative bacterial cultures showed a reduction of bioburden in silver-treated wounds in wild type mice. Unexpectedly, there was no decrease in bioburden in the silver-treated diabetic wounds compared to the control diabetic wounds, despite improved healing in the silver-treated diabetic wounds. Staphylococcus xylosus, a known biofilm producer, was the only bacteria identified in all the wounds. In vitro studies showed S. xylosus produced biofilms faster in higher glucose environments; this may explain the increased bioburden in the wounds in diabetic mice compared to wild type mice. The results demonstrate improved healing and reduced bioburden in normal wounds with silver dressings. In contrast, silver dressings improved healing in diabetic wounds despite no effect on bioburden, suggesting silver may have beneficial effects in addition to its antimicrobial properties.