Eosinophil biology from the standpoint of metabolism: implications for metabolic disorders and asthma.

Eosinophils, recognized for their immune and remodeling functions and participation in allergic inflammation, have recently garnered attention due to their impact on host metabolism, especially in the regulation of adipose tissue. Eosinophils are now known for their role in adipocyte beiging, adipokine secretion, and adipose tissue inflammation. This intricate interaction involves complex immune and metabolic processes, carrying significant implications for systemic metabolic health. Importantly, the interplay between eosinophils and adipocytes is bidirectional, revealing the dynamic nature of the immune-metabolic axis in adipose tissue. While the homeostatic regulatory role of eosinophils in adipose tissue is appreciated, this relationship in the context of obesity or allergic inflammation is much less understood. Mechanistic details of eosinophil-adipose interactions, especially the direct regulation of adipocytes by eosinophils, are also lacking. Another poorly understood aspect is the metabolism of the eosinophils themselves, encompassing metabolic shifts during eosinophil subset transitions in different tissue microenvironments, along with potential effects of host metabolism on the programming of eosinophil hematopoiesis and the resulting plasticity. This review consolidates recent research in this emerging and fascinating frontier of eosinophil investigation, identifying unexplored areas and presenting innovative perspectives on eosinophil biology in the context of metabolic disorders and associated health conditions, including asthma.

Single cell profiling to determine influence of wheeze and early-life viral infection on developmental programming of airway epithelium.

Although childhood asthma is in part an airway epithelial disorder, the development of the airway epithelium in asthma is not understood. We sought to characterize airway epithelial developmental phenotypes in those with and without recurrent wheeze and the impact of infant infection with respiratory syncytial virus (RSV). Nasal airway epithelial cells (NAECs) were collected at age 2-3 years from an a priori designed nested birth cohort of children from four mutually exclusive groups of wheezers/non-wheezers and RSV-infected/uninfected in the first year of life. NAECs were cultured in air-liquid interface differentiation conditions followed by a combined analysis of single cell RNA sequencing (scRNA-seq) and in vitro infection with respiratory syncytial virus (RSV). NAECs from children with a wheeze phenotype were characterized by abnormal differentiation and basal cell activation of developmental pathways, plasticity in precursor differentiation and a delayed onset of maturation. NAECs from children with wheeze also had increased diversity of currently known RSV receptors and blunted anti-viral immune responses to in vitro infection. The most dramatic changes in differentiation of cultured epithelium were observed in NAECs derived from children that had both wheeze and RSV in the first year of life. Together this suggests that airway epithelium in children with wheeze is developmentally reprogrammed and characterized by increased barrier permeability, decreased antiviral response, and increased RSV receptors, which may predispose to and amplify the effects of RSV infection in infancy and susceptibility to other asthma risk factors that interact with the airway mucosa. SUMMARY: Nasal airway epithelial cells from children with wheeze are characterized by altered development and increased susceptibility to RSV infection.

scRNA-seq profiling of human granulocytes reveals expansion of developmentally flexible neutrophil precursors with mixed neutrophil and eosinophil properties in asthma.

Neutrophils and eosinophils share common hematopoietic precursors and usually diverge into distinct lineages with unique markers before being released from their hematopoietic site, which is the bone marrow (BM). However, previous studies identified an immature Ly6g(+) Il-5Rα(+) neutrophil population in mouse BM, expressing both neutrophil and eosinophil markers suggesting hematopoietic flexibility. Moreover, others have reported neutrophil populations expressing eosinophil-specific cell surface markers in tissues and altered disease states, confusing the field regarding eosinophil origins, function, and classification. Despite these reports, it is still unclear whether hematopoietic flexibility exists in human granulocytes. To answer this, we utilized single-cell RNA sequencing and cellular indexing of transcriptomes and epitopes by sequencing to profile human BM and circulating neutrophils and eosinophils at different stages of differentiation and determine whether neutrophil plasticity plays role in asthmatic inflammation. We show that immature metamyelocyte neutrophils in humans expand during severe asthmatic inflammation and express both neutrophil and eosinophil markers. We also show an increase in trilobed eosinophils with mixed neutrophil and eosinophil markers in allergic asthma and that interleukin-5 promotes differentiation of immature blood neutrophils into trilobed eosinophilic phenotypes, suggesting a mechanism of emergency granulopoiesis to promote myeloid inflammatory or remodeling response in patients with chronic asthma. By providing insights into unexpectedly flexible granulocyte biology and demonstrating emergency hematopoiesis in asthma, our results highlight the importance of granulocyte plasticity in eosinophil development and allergic diseases.

Polysaccharide hydrogel based 3D printed tumor models for chemotherapeutic drug screening.

A series of stable and ready-to-use bioinks have been developed based on the xeno-free and tunable hydrogel (VitroGel) system. Cell laden scaffold fabrication with optimized polysaccharide-based inks demonstrated that Ink H4 and RGD modified Ink H4-RGD had excellent rheological properties. Both bioinks were printable with 25-40 kPa extrusion pressure, showed 90% cell viability, shear-thinning and rapid shear recovery properties making them feasible for extrusion bioprinting without UV curing or temperature adjustment. Ink H4-RGD showed printability between 20 and 37 °C and the scaffolds remained stable for 15 days at temperature of 37 °C. 3D printed non-small-cell lung cancer (NSCLC) patient derived xenograft cells (PDCs) showed rapid spheroid growth of size around 500 µm in diameter and tumor microenvironment formation within 7 days. IC50 values demonstrated higher resistance of 3D spheroids to docetaxel (DTX), doxorubicin (DOX) and erlotinib compared to 2D monolayers of NSCLC-PDX, wild type triple negative breast cancer (MDA-MB-231 WT) and lung adenocarcinoma (HCC-827) cells. Results of flow property, shape fidelity, scaffold stability and biocompatibility of H4-RGD suggest that this hydrogel could be considered for 3D cell bioprinting and also for in-vitro tumor microenvironment development for high throughput screening of various anti-cancer drugs.

Cause-specific mortality of children younger than 5 years in communities receiving biannual mass azithromycin treatment in Niger: verbal autopsy results from a cluster-randomised controlled trial.

BACKGROUND: The Macrolides Oraux pour Réduire les Décès avec un Oeil sur la Résistance (MORDOR) trial found that biannual mass distribution of azithromycin to children younger than 5 years in Niger reduced the primary outcome of all-cause mortality by 18%. We aimed to determine the causes of mortality among deceased children using verbal autopsy. METHODS: In this 2-year cluster-randomised controlled trial, 594 community clusters in Niger were randomly allocated (1:1 ratio) to receive biannual mass distributions of either oral azithromycin (approximately 20 mg per kg of bodyweight) or placebo targeted to children aged 1-59 months. Participants, study investigators, and field workers were masked to treatment allocation. Between Nov 23, 2014, and July 31, 2017, 3615 child deaths were recorded by use of biannual house-to-house censuses, and verbal autopsies were done between May 26, 2015, and May 17, 2018, to identify cause of death. Cause-specific mortality, as assessed by verbal autopsy, was a prespecified secondary outcome. This trial is completed and is registered with ClinicalTrials.gov, NCT02047981. FINDINGS: Between Nov 23, 2014, and July 31, 2017, 303 communities (n=40 375 children at baseline) in Niger received mass azithromycin and 291 communities (n=35 747 children at baseline) received placebo. Treatment coverage was 90·3% (SD 10·6) in the azithromycin group and 90·4% (10·1) in the placebo group. No communities were lost to follow-up. In total, 1727 child deaths in the azithromycin group and 1888 child deaths in the placebo group were reported from the population censuses. Of these, the cause of death for 1566 (90·7%) children in the azithromycin group and 1735 (91·9%) children in the placebo group were ascertained by verbal autopsy interviews. In the azithromycin group, 437 (27·9%) deaths were due to malaria, 252 (16·1%) deaths were due to pneumonia, and 234 (14·9%) deaths were due to diarrhoea. In the placebo group, 493 (28·4%) deaths were due to malaria, 275 (15·9%) deaths were due to pneumonia, and 251 (14·5%) deaths were due to diarrhoea. Relative to communities that received placebo, child mortality in communities that received azithromycin was lower for malaria (incidence rate ratio 0·78, 95% CI 0·66-0·92; p=0·0029), dysentery (0·65, 0·44-0·94; p=0·025), meningitis (0·67, 0·46-0·97; p=0·036), and pneumonia (0·83, 0·68-1·00; p=0·051). The distribution of causes of death did not differ significantly between the two study groups (p=0·98). INTERPRETATION: Mass azithromycin distribution resulted in approximately a third fewer deaths in children aged 1-59 months due to meningitis and dysentery, and a fifth fewer deaths due to malaria and pneumonia. The lack of difference in the distribution of causes of death between the azithromycin and placebo groups could be attributable to the broad spectrum of azithromycin activity and the study setting, in which most childhood deaths were due to infections. FUNDING: Bill & Melinda Gates Foundation.

Plasma homocysteine is elevated in COPD patients and is related to COPD severity.

BACKGROUND: Although recent studies have found that total plasma homocysteine (tHCY) and chronic obstructive pulmonary disease (COPD) are both risk factors for cardiac disease, there have been few studies of plasma homocysteine levels in COPD patients. We tested the hypothesis that total plasma homocysteine (tHCY) would be elevated in patients diagnosed with COPD compared with controls. METHODS: We studied 29 COPD outpatients and 25 asymptomatic subjects (controls) over age 55 years with measurement of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), St. Georges Respiratory Questionnaire (SGRQ) score, tHCY and serum C-reactive protein (sCRP). RESULTS: There was no difference between controls vs. COPD patients in mean age or gender but mean (SD) FEV1 was 2.25 (0.77) vs. 1.43 (0.60) L; FEV1% predicted 76.1 (17.2) vs. 49.1 (16.3) p < 0.001 in both cases. Median (IQR) tHCY was 8.22 (6.63, 9.55) in controls vs. 10.96 (7.56, 13.60) micromol/l for COPD, p = 0.006 and sCRP 0.89 (0.47, 2.55) vs. 2.05 (0.86, 6.19) mg/l, p = 0.023. tHCY(log) was also higher in (r, p) smokers (0.448, 0.001), patients with low FEV1% (-0.397, 0.003), males (0.475, < 0.001), but high SGRQ Total score (0.289, 0.034), and high sCRP (0.316, 0.038). tHCY(log) was independently related to (regression coefficient, p) sCRP(log) (0.087, 0.024), male gender (0.345, < 0.001) and presence of COPD (0.194, 0.031). Median (IQR) tHCY GOLD Stage I and II 8.05 (7.28, 11.04), GOLD Stage III and IV: 11.83 (9.30, 18.30); p = 0.023. CONCLUSIONS: Plasma homocysteine is significantly elevated in COPD patients relative to age and sex-matched controls and is related to serum CRP and COPD severity.

Plasma homocysteine is elevated in COPD patients and is related to COPD severity.

BACKGROUND: Although recent studies have found that total plasma homocysteine (tHCY) and chronic obstructive pulmonary disease (COPD) are both risk factors for cardiac disease, there have been few studies of plasma homocysteine levels in COPD patients. We tested the hypothesis that total plasma homocysteine (tHCY) would be elevated in patients diagnosed with COPD compared with controls. METHODS: We studied 29 COPD outpatients and 25 asymptomatic subjects (controls) over age 55 years with measurement of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), St. Georges Respiratory Questionnaire (SGRQ) score, tHCY and serum C-reactive protein (sCRP). RESULTS: There was no difference between controls vs. COPD patients in mean age or gender but mean (SD) FEV1 was 2.25 (0.77) vs. 1.43 (0.60) L; FEV1 per cent predicted 76.1 (17.2) vs. 49.1 (16.3) p < 0.001 in both cases. Median (IQR) tHCY was 8.22 (6.63, 9.55) in controls vs. 10.96 (7.56, 13.60) micromol/l for COPD, p = 0.006 and sCRP 0.89 (0.47, 2.55) vs. 2.05 (0.86, 6.19) mg/l, p = 0.023. tHCY(log) was also higher in (r, p) smokers (0.448, 0.001), patients with low FEV1 per cent (-0.397, 0.003), males (0.475, < 0.001), but high SGRQ Total score (0.289, 0.034), and high sCRP (0.316, 0.038). tHCY(log) was independently related to (regression coefficient, p) sCRP(log) (0.087, 0.024), male gender (0.345, < 0.001) and presence of COPD (0.194, 0.031). Median (IQR) tHCY GOLD Stage I and II 8.05 (7.28, 11.04), GOLD Stage III and IV: 11.83 (9.30, 18.30); p = 0.023. CONCLUSIONS: Plasma homocysteine is significantly elevated in COPD patients relative to age and sex-matched controls and is related to serum CRP and COPD severity.