and ovalbumin-challenged mice. See the publication by Abdala-Valencia et al. 1 for a detailed description of the ovalbumin model of asthma and eosinophil sorting protocol.

Bone marrow is a hematopoietic site harboring multiple populations of myeloid cells in different stages of differentiation. Murine bone marrow eosinophils are traditionally identified by Siglec‐F(+) staining using flow cytometry, whereas neutrophils are characterized by Ly6G(+) expression. However, using flow cytometry to characterize bone marrow hematopoietic cells in wild‐type mice, we found substantial gray areas in identification of these cells. Siglec‐F(+) mature eosinophil population constituted only a minority of bone marrow Lin(+)CD45(+) pool (5%). A substantial population of Siglec‐F(−) cells was double positive for neutrophil marker Ly6G and eosinophil lineage marker, IL‐5Rα. This granulocyte population with mixed neutrophil and eosinophil characteristics is typically attributable to neutrophil pool based on neutral granule staining and expression of Ly6G and myeloid peroxidase. It is distinct from Lineage(−) myeloid progenitors or Siglec‐F(+)Ly6G(+) maturing eosinophil precursors, and can be accurately identified by Lineage(+) staining and positive expression of markers IL‐5Rα and Ly6G. At 15–50% of all CD45(+) hematopoietic cells in adult mice (percentage varies by sex and age), this is a surprisingly dominant population, which increases with age in both male and female mice. RNA‐seq characterization of these cells revealed a complex immune profile and the capacity to secrete constituents of the extracellular matrix. When sorted from bone marrow, these resident cells had neutrophilic phenotype but readily acquired all characteristics of eosinophils when cultured with G‐CSF or IL‐5, including expression of Siglec‐F and granular proteins (Epx, Mbp). Surprisingly, these cells were also able to differentiate into Ly6C(+) monocytes when cultured with M‐CSF. Herein described is the discovery of an unexpected hematopoietic flexibility of a dominant population of multipotent myeloid cells, typically categorized as neutrophils, but with the previously unknown plasticity to contribute to mature pools of eosinophils and monocytes.

No abstract

RATIONALE: There is strong epidemiological evidence that the prevalence of atopy and asthma changes with puberty, but the mechanisms involved are poorly understood. We have previously discovered that multiple hormonal systems are dysregulated in allergic disease. Since sex steroids are known to interact with other hormonal systems, we sought to determine the effects of puberty on non-sex hormones in allergic patients. METHODS: Serum samples were collected from pediatric patients (36 allergic cases and 18 healthy controls) and adult patients (39 asthmatics and 35 healthy controls). A comprehensive profiling of the endocrine system was performed using magnetic bead multiplex assays. RESULTS: Several key non-sex hormones are dysregulated in allergic patients: growth hormone (GH), C-peptide, insulin, triiodothyronine (T3), and thyroxine (T4). Pre-puberty male allergic subjects had higher levels of GH, T3, and T4 compared to healthy controls, while female allergic children had lower levels of C-peptide and insulin. Strikingly, the opposite pattern emerged after puberty. Male and female asthmatic adults had lower levels of GH compared to controls, and female asthma patients had lower levels of T3 and T4. Post-puberty, C-peptide and insulin levels in females reached levels observed in males. CONCLUSIONS: The onset of puberty profoundly affects not only sex hormones, but also other components of the endocrine system. As these hormones play important roles in homeostasis and immunity, future gender studies should focus not only on the direct effects of estrogen, but also on gender-influenced changes in central metabolism and other hormonal systems.

RATIONALE: Obesity increases asthma severity. Weight loss in bariatric surgery improves asthma symptoms and reduces airway hyperresponsiveness. We hypothesized that vertical sleeve gastrectomy (VSG), a model of bariatric surgery, would reduce airway pathology in allergen-challenged obese mice. METHODS: Five-week old C57BL6 mice were fed a high fat diet (HFD -45% kcal fat) or normal chow and concurrently challenged with intranasal house dust mite (HDM) allergen (25 mg) or saline 3 days/week for 8 weeks. These challenged mice immediately underwent VSG or sham surgery, or no surgery (NS) as control (n55 per group). After one-week recovery, mice were returned to HFD and HDM challenges for four weeks. Twenty-four hours after the final HDM challenge, the mice were tested for airway responsiveness to increasing doses of methacholine delivered intravenously, and lung mechanics were evaluated using Flexivent (SciReq). Blood and bronchoalveolar lavage (BAL) with saline were collected. Harvested lung slices were stained with Masson's trichrome, Periodic acid Schiff or hematoxylin and eosin stains. Percent trichrome staining was quantified using Image J (NIH). Interleukin (IL)-13, IL-5, glucagon-like peptide-1, transforming growth factor-beta, insulin and leptin were measured in blood and/or lavage fluid using ELISA. RESULTS: VSG induced significant weight loss and reduction of plasma leptin levels (p<0.05). Airway reactivity to bronchoconstrictor, airway tissue inflammation and percent BAL eosinophils (13.3% NS, 4.7% sham, 0.8% VSG) were reduced in HFD-fed, HDM-challenged mice following VSG compared to sham or NS (p<0.05). CONCLUSIONS: Weight loss surgery in obese, chronically allergenchallenged mice induces metabolic changes associated with improved airway inflammation and resistance.