Population genetic structure of Schistosoma bovis and S. curassoni collected from cattle in Mali.

Schistosomiasis is of medical and veterinary importance. Despite the critical situation of schistosomiasis in sub-Saharan Africa, few molecular epidemiological studies have been carried out to determine the role of animals in its transmission. In Mali, it has been over three decades since the last molecular study of animal schistosomes was carried out. It is now urgent to identify circulating strains of the parasite because of potential interactions with other schistosome species, which could complicate disease control. The aim of our work was to study the composition and genetic structure of schistosome populations collected from cattle. The prevalence of schistosome was 23.9%, with the prevalences of Schistosoma bovis (Sb) and S. curassoni (Sc) estimated at 12.6% and 9.8%, respectively. No hybrid strains or S. haematobium were found. The parasites displayed distinct geographical distribution with Sb dominant in Bamako (78.8% and 98% in Central Bamako Slaughterhouse and Sabalibougou Slaughterhouses, respectively) and Sc dominant in Kayes (95.3%). Of the 476 parasites with a complete genetic profile, 60.4% were pure Sc, and were mainly from Kayes. We identified two clusters at the site level (Fst of 0.057 and 0.042 for Sb and Sc, respectively). Cluster 1 was predominantly composed of pure Sb parasites and cluster 2 was mainly composed of pure Sc parasites, from Bamako and Kayes, respectively. Our study shows that cattle schistosomiasis remains endemic in Mali with S. bovis and S. curassoni. A robust genetic structure between the different schistosome populations was identified, which included two clusters based on the geographical distribution of the parasites.

Title: Structure génétique des populations de Schistosoma bovis et S. curassoni collectées chez des bovins au Mali. Abstract: La schistosomiase revêt une grande importance médicale et vétérinaire. Malgré la situation critique de la schistosomiase en Afrique subsaharienne, peu d'études épidémiologiques moléculaires ont été réalisées pour déterminer le rôle des animaux dans sa transmission. Au Mali, cela fait plus de trois décennies que la dernière étude moléculaire des schistosomes animaux a été réalisée. Il est désormais urgent d'identifier les souches circulantes du parasite en raison des interactions potentielles avec d'autres espèces de schistosomes, ce qui pourrait compliquer la lutte contre la maladie. Le but de notre travail était d'étudier la composition et la structure génétique des populations de schistosomes collectées chez des bovins. La prévalence des schistosomes était de 23,9 %, celles de Schistosoma bovis (Sb) et de S. curassoni (Sc) étant respectivement estimées à 12,6 % et 9,8 %. Aucune souche hybride ni S. haematobium n'ont été trouvés. Les parasites présentaient une répartition géographique distincte avec Sb dominant à Bamako (respectivement 78,8 % et 98 % aux Abattoirs Centraux de Bamako et aux Abattoirs de Sabalibougou) et Sc dominant à Kayes (95,3 %). Sur les 476 parasites ayant un profil génétique complet, 60,4 % étaient des Sc purs, et provenaient principalement de Kayes. Nous avons identifié deux clusters au niveau du site (Fst de 0,057 et 0,042 pour Sb et Sc, respectivement). Le groupe 1 était principalement composé de parasites Sb purs et le groupe 2 était principalement composé de parasites Sc purs, provenant respectivement de Bamako et de Kayes. Notre étude montre que la schistosomiase bovine reste endémique au Mali, avec S. bovis and S. curassoni. Une structure génétique robuste entre les différentes populations de schistosomes a été identifiée, comprenant deux groupes basés sur la répartition géographique des parasites.

Small-Molecule Activation of Protein Phosphatase 2A Counters Bleomycin-Induced Fibrosis in Mice.

The activity of protein phosphatase 2A (PP2A), a serine-threonine phosphatase, is reduced in the lung fibroblasts of idiopathic pulmonary fibrosis (IPF) patients. The objective of this study was to determine whether the reactivation of PP2A could reduce fibrosis and preserve the pulmonary function in a bleomycin (BLM) mouse model. Here, we present a new class of direct small-molecule PP2A activators, diarylmethyl-pyran-sulfonamide, exemplified by ATUX-1215. ATUX-1215 has improved metabolic stability and bioavailability compared to our previously described PP2A activators. Primary human lung fibroblasts were exposed to ATUX-1215 and an older generation PP2A activator in combination with TGFß. ATUX-1215 treatment enhanced the PP2A activity, reduced the phosphorylation of ERK and JNK, and reduced the TGFß-induced expression of ACTA2, FN1, COL1A1, and COL3A1. C57BL/6J mice were administered 5 mg/kg ATUX-1215 daily following intratracheal instillation of BLM. Three weeks later, forced oscillation and expiratory measurements were performed using the Scireq Flexivent System. ATUX-1215 prevented BLM-induced lung physiology changes, including the preservation of normal PV loop, compliance, tissue elastance, and forced vital capacity. PP2A activity was enhanced with ATUX-1215 and reduced collagen deposition within the lungs. ATUX-1215 also prevented the BLM induction of Acta2, Ccn2, and Fn1 gene expression. Treatment with ATUX-1215 reduced the phosphorylation of ERK, p38, JNK, and Akt and the secretion of IL-12p70, GM-CSF, and IL1α in BLM-treated animals. Delayed treatment with ATUX-1215 was also observed to slow the progression of lung fibrosis. In conclusion, our study indicates that the decrease in PP2A activity, which occurs in fibroblasts from the lungs of IPF subjects, could be restored with ATUX-1215 administration as an antifibrotic agent.

Genetic profiles of Schistosoma haematobium parasites from Malian transmission hotspot areas.

BACKGROUND: Although schistosomiasis is a public health issue in Mali, little is known about the parasite genetic profile. The purpose of this study was to analyze the genetic profile of the schistosomes of Schistosoma haematobium group in school-aged children in various sites in Mali. METHODS: Urine samples were collected from 7 to 21 November 2021 and subjected to a filtration method for the presence S. haematobium eggs. The study took place in two schistosomiasis endemic villages (Fangouné Bamanan and Diakalèl), qualified as hotspots according to the World Health Organization (WHO) definition. Molecular genotyping on both Cox1 and ITS2/18S was used for eggs' taxonomic assignation. RESULTS: A total of 970 miracidia were individually collected from 63 school-aged children and stored on Whatman FTA cards for molecular analysis. After genotyping 42.0% (353/840) and 58.0% (487/840) of miracidia revealed Schistosoma bovis and S. haematobium Cox1 profiles, respectively; 95.7 (885/925) and 4.3% (40/925) revealed S. haematobium and S. haematobium/S. curassoni profiles for ITS/18S genes, respectively. There was a significant difference in the Cox1 and ITS2/18S profile distribution according to the village (P < 0.0001). Overall, 45.6% (360/789) were hybrids, of which 72.0% (322/447) were from Diakalèl. Three hybrids' profiles (Sb/Sc_ShxSc with 2.3%; Sb/Sc_ShxSh with 40.5%; Sh_ShxSc with 2.8%) and one pure profile (Sh_ShxSh with 54.4%) were identified. CONCLUSION: Our findings show, for the first time to our knowledge, high prevalence of hybrid schistosomes in Mali. More studies are needed on population genetics of schistosomes at the human and animal interface to evaluate the parasite's gene flow and its consequences on epidemiology of the disease as well as the transmission to humans.

Evaluating Novel Protein Phosphatase 2A Activators as Therapeutics for Emphysema.

The activity of PP2A (protein phosphatase 2A), a serine-threonine phosphatase, is reduced by chronic cigarette smoke (SM) exposure and α-1 antitrypsin (AAT) deficiency, and chemical activation of PP2A reduces the loss of lung function in SM-exposed mice. However, the previously studied PP2A-activator tricyclic sulfonamide compound DBK-1154 has low stability to oxidative metabolism, resulting in fast clearance and low systemic exposure. Here we compare the utility of a new more stable PP2A activator, ATUX-792, versus DBK-1154 for the treatment of SM-induced emphysema. ATUX-792 was also tested in human bronchial epithelial cells and a mouse model of AAT deficiency, Serpina1a-e-knockout mice. Human bronchial epithelial cells were treated with ATUX-792 or DBK-1154, and cell viability, PP2A activity, and MAP (mitogen-activated protein) kinase phosphorylation status were examined. Wild-type mice received vehicle, DBK-1154, or ATUX-792 orally in the last 2 months of 4 months of SM exposure, and 8-month-old Serpina1a-e-knockout mice received ATUX-792 daily for 4 months. Forced oscillation and expiratory measurements and histology analysis were performed. Treatment with ATUX-792 or DBK-1154 resulted in PP2A activation, reduced MAP kinase phosphorylation, immune cell infiltration, reduced airspace enlargements, and preserved lung function. Using protein arrays and multiplex assays, PP2A activation was observed to reduce AAT-deficient and SM-induced release of CXCL5, CCL17, and CXCL16 into the airways, which coincided with reduced neutrophil lung infiltration. Our study indicates that suppression of the PP2A activity in two models of emphysema could be restored by next-generation PP2A activators to impact lung function.

A duplex tetra-primer ARMS-PCR assay to discriminate three species of the Schistosoma haematobium group: Schistosoma curassoni, S. bovis, S. haematobium and their hybrids.

BACKGROUND: The use of applications involving single nucleotide polymorphisms (SNPs) has greatly increased since the beginning of the 2000s, with the number of associated techniques expanding rapidly in the field of molecular research. Tetra-primer amplification refractory mutation system-PCR (T-ARMS-PCR) is one such technique involving SNP genotyping. It has the advantage of amplifying multiple alleles in a single reaction with the inclusion of an internal molecular control. We report here the development of a rapid, reliable and cost-effective duplex T-ARMS-PCR assay to distinguish between three Schistosoma species, namely Schistosoma haematobium (human parasite), Schistosoma bovis and Schistosoma curassoni (animal parasites), and their hybrids. This technique will facilitate studies of population genetics and the evolution of introgression events. METHODS: During the development of the technique we focused on one of the five inter-species internal transcribed spacer (ITS) SNPs and one of the inter-species 18S SNPs which, when combined, discriminate between all three Schistosoma species and their hybrid forms. We designed T-ARMS-PCR primers to amplify amplicons of specific lengths for each species, which in turn can then be visualized on an electrophoresis gel. This was further tested using laboratory and field-collected adult worms and field-collected larval stages (miracidia) from Spain, Egypt, Mali, Senegal and Ivory Coast. The combined duplex T-ARMS-PCR and ITS + 18S primer set was then used to differentiate the three species in a single reaction. RESULTS: The T-ARMS-PCR assay was able to detect DNA from both species being analysed at the maximum and minimum levels in the DNA ratios (95/5) tested. The duplex T-ARMS-PCR assay was also able to detect all hybrids tested and was validated by sequencing the ITS and the 18S amplicons of 148 of the field samples included in the study. CONCLUSIONS: The duplex tetra-primer ARMS-PCR assay described here can be applied to differentiate between Schistosoma species and their hybrid forms that infect humans and animals, thereby providing a method to investigate the epidemiology of these species in endemic areas. The addition of several markers in a single reaction saves considerable time and is of long-standing interest for investigating genetic populations.

Ultrasound aspects and risk factors associated with urogenital schistosomiasis among primary school children in Mali.

BACKGROUND: Urogenital schistosomiasis is endemic in Mali and is a major cause of serious morbidity in large parts of the world. This disease is responsible for many socio-economic and public health issues. The aim of this study was to investigate the impact of the disease on morbidity and to describe demographic and socioeconomic factors in relation to the status of children with urogenital schistosomiasis in Mali. METHODS: We conducted a cross-sectional study in November 2021 of 971 children aged 6 to 14 years selected at random from six schools in three districts in the Kayes Region of Mali. Demographic and socioeconomic data were collected on survey forms. Clinical data were collected following a medical consultation. Hematuria was systematically searched for through the use of strips. The search for Schistosoma haematobium eggs in urine was done via the filtration method. The urinary tract was examined by ultrasound. Associations between each of these variables and disease infection were tested using multivariate logistic regression. RESULTS: The overall prevalence of urinary schistosomiasis detected was 50.2%. The average intensity of infection was 36 eggs/10 ml of urine. The associated risk factors for urogenital schistosomiasis showed that children who bathed, used the river/pond as a domestic water source, and who habitually urinated in the river/pond were more affected (P < 0.05). Children with farming parents were most affected (P = 0.032). The collection of clinical signs revealed that boys had more pollakiuria (58.6%) and dysuria (46.4%) than girls. Ultrasound data showed that focal lesion rates were recorded in all villages with the lowest rate in Diakalel (56.1%). Ultrasound and parasitological findings showed that irregularity and thickening were strongly associated with urinary schistosomiasis (P < 0.0001). CONCLUSIONS: Schistosoma haematobium infection was still endemic in the study site despite more than a decade of mass treatment with praziquantel. However, the high percentage of symptoms associated with high intensity reinforces the idea that further studies in terms of schistosomiasis-related morbidity are still needed.

LRP1 loss in airway epithelium exacerbates smoke-induced oxidative damage and airway remodeling.

The LDL receptor-related protein 1 (LRP1) partakes in metabolic and signaling events regulated in a tissue-specific manner. The function of LRP1 in airways has not been studied. We aimed to study the function of LRP1 in smoke-induced disease. We found that bronchial epithelium of patients with chronic obstructive pulmonary disease and airway epithelium of mice exposed to smoke had increased LRP1 expression. We then knocked out LRP1 in human bronchial epithelial cells in vitro and in airway epithelial club cells in mice. In vitro, LRP1 knockdown decreased cell migration and increased transforming growth factor ß activation. Tamoxifen-inducible airway-specific LRP1 knockout mice (club Lrp1-/-) induced after complete lung development had increased inflammation in the bronchoalveolar space and lung parenchyma at baseline. After 6 months of smoke exposure, club Lrp1-/- mice showed a combined restrictive and obstructive phenotype, with lower compliance, inspiratory capacity, and forced expiratory volume0.05/forced vital capacity than WT smoke-exposed mice. This was associated with increased values of Ashcroft fibrotic index. Proteomic analysis of room air exposed-club Lrp1-/- mice showed significantly decreased levels of proteins involved in cytoskeleton signaling and xenobiotic detoxification as well as decreased levels of glutathione. The proteome fingerprint created by smoke eclipsed many of the original differences, but club Lrp1-/- mice continued to have decreased lung glutathione levels and increased protein oxidative damage and airway cell proliferation. Therefore, LRP1 deficiency leads to greater lung inflammation and damage and exacerbates smoke-induced lung disease.

COVID-19: A pluralistic and integrated approach for efficient management of the pandemic.

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which triggered the ongoing pandemic, was first discovered in China in late 2019. SARS-CoV-2 is a respiratory virus responsible for coronavirus disease 2019 (COVID-19) that often manifests as a pneumonic syndrome. In the context of the pandemic, there are mixed views on the data provided by epidemiologists and the information collected by hospital clinicians about their patients. In addition, the literature reports a large proportion of patients free of pneumonia vs a small percentage of patients with severe pneumonia among confirmed COVID-19 cases. This raises the issue of the complexity of the work required to control or contain the pandemic. We believe that an integrative and pluralistic approach will help to put the analyses into perspective and reinforce collaboration and creativity in the fight against this major scourge. This paper proposes a comprehensive and integrative approach to COVID-19 research, prevention, control, and treatment to better address the pandemic. Thus, this literature review applies a pluralistic approach to fight the pandemic.

Model-based assessment of Chikungunya and O'nyong-nyong virus circulation in Mali in a serological cross-reactivity context.

Serological surveys are essential to quantify immunity in a population but serological cross-reactivity often impairs estimates of the seroprevalence. Here, we show that modeling helps addressing this key challenge by considering the important cross-reactivity between Chikungunya (CHIKV) and O'nyong-nyong virus (ONNV) as a case study. We develop a statistical model to assess the epidemiology of these viruses in Mali. We additionally calibrate the model with paired virus neutralization titers in the French West Indies, a region with known CHIKV circulation but no ONNV. In Mali, the model estimate of ONNV and CHIKV prevalence is 30% and 13%, respectively, versus 27% and 2% in non-adjusted estimates. While a CHIKV infection induces an ONNV response in 80% of cases, an ONNV infection leads to a cross-reactive CHIKV response in only 22% of cases. Our study shows the importance of conducting serological assays on multiple cross-reactive pathogens to estimate levels of virus circulation.

Molecular Detection of Microorganisms Associated with Small Mammals and Their Ectoparasites in Mali.

Small mammals are the natural reservoirs for many zoonotic pathogens. Using molecular tools, we assessed the prevalence of bacteria and protozoans in small mammals and their ectoparasites in Faladjè, Bougouni, and Bamoko, Mali. A total of 130 small mammals belonging to 10 different species were captured, of which 74 (56.9%) were infested by ectoparasites, including Laelaps echidnina, Xenopsylla cheopis, Amblyomma variegatum, Rhipicephalus sanguineus sensu lato, and Haemaphysalis spp. nymphs. DNA of Bartonella was found in 14/75 (18.7%), 6/48 (12.5%), and 3/7 (42.8%) small mammals from Faladjè, Bougouni, and Bamako, respectively. In Faladjè, Bartonella DNA was detected in 31/68 (45.6%) of L. echidnina and 14/22 (63.6%) of X. cheopis. In Bougouni, it was found in 2/26 (7.7%) of L. echidnina and 10/42 (23.8%) of X. cheopis. The sequences of Bartonella obtained from small mammals were close to those of Bartonella mastomydis, Bartonella elizabethae, and uncultured Bartonella spp. In Faladjè, Coxiella burnetii DNA was detected in 64.4% (29/45) of Haemaphysalis spp. ticks, 4.5% (2/44) of Mastomys erythroleucus, 12.5% (1/8) of Praomys daltoni, and 1.5% (1/68) of L. echidnina. We found DNA of Wolbachia in X. cheopis from Faladjè and DNA of Rickettsia africae and Ehrlichia ruminantium in Am. variegatum from Bougouni. The results of our study show that several small mammal species harbor and may serve as potential reservoirs of Bartonella spp., likely to play a major role in the maintenance, circulation, and potential transmission of bacteria in Mali. The pathogenicity of these bacteria for humans or animals remains to be demonstrated.

Elevated S100A9 expression in chronic rhinosinusitis coincides with elevated MMP production and proliferation in vitro.

Chronic rhinosinusitis (CRS) is a common condition associated with inflammation and tissue remodeling of the nose and paranasal sinuses, frequently occurring with nasal polyps and allergies. Here we investigate inflammation and the protease profile in nasal tissues and plasma from control non-CRS patients and CRS patients. Gene expression for several cytokines, proteases, and antiproteases was quantified in nasal tissue from non-CRS and CRS subjects with nasal polyps. Elevated expression of S100A9, IL1A, MMP3, MMP7, MMP11, MMP25, MMP28, and CTSK was observed in tissue from CRS subjects with nasal polyps compared to control tissue. Tissue protein analysis confirmed elevated levels of these targets compared to controls, and increased MMP3 and MMP7 observed in CRS subjects with nasal polyps compared to CRS subjects without polyps. Plasma concentrations of MMP3 and MMP7 were elevated in the CRS groups compared to controls. The nasal cell line, CCL-30, was exposed to S100A9 protein, resulting in increased MMP3, MMP7, and CTSK gene expression and elevated proliferation. Silencing MMP3 significantly reduced S100A9-mediated cell proliferation. Therefore, the elevated expression of S100A9 and MMPs are observed in CRS nasal tissue and S100A9 stimulated MMP3 responses to contribute to elevated nasal cell proliferation.

Cigarette smoke induction of S100A9 contributes to chronic obstructive pulmonary disease.

S100 calcium-binding protein A9 (S100A9) is elevated in plasma and bronchoalveolar lavage fluid (BALF) of patients with chronic obstructive pulmonary disease (COPD), and aging enhances S100A9 expression in several tissues. Currently, the direct impact of S100A9-mediated signaling on lung function and within the aging lung is unknown. Here, we observed that elevated S100A9 levels in human BALF correlated with age. Elevated lung levels of S100A9 were higher in older mice compared with in young animals and coincided with pulmonary function changes. Both acute and chronic exposure to cigarette smoke enhanced S100A9 levels in age-matched mice. To examine the direct role of S100A9 on the development of COPD, S100a9-/- mice or mice administered paquinimod were exposed to chronic cigarette smoke. S100A9 depletion and inhibition attenuated the loss of lung function, pressure-volume loops, airway inflammation, lung compliance, and forced expiratory volume in 0.05 s/forced vital capacity, compared with age-matched wild-type or vehicle-administered animals. Loss of S100a9 signaling reduced cigarette smoke-induced airspace enlargement, alveolar remodeling, lung destruction, ERK and c-RAF phosphorylation, matrix metalloproteinase-3 (MMP-3), matrix metalloproteinase-9 (MMP-9), monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6), and keratinocyte-derived chemokine (KC) release into the airways. Paquinimod administered to nonsmoked, aged animals reduced age-associated loss of lung function. Since fibroblasts play a major role in the production and maintenance of extracellular matrix in emphysema, primary lung fibroblasts were treated with the ERK inhibitor LY3214996 or the c-RAF inhibitor GW5074, resulting in less S100A9-induced MMP-3, MMP-9, MCP-1, IL-6, and IL-8. Silencing Toll-like receptor 4 (TLR4), receptor for advanced glycation endproducts (RAGE), or extracellular matrix metalloproteinase inducer (EMMPRIN) prevented S100A9-induced phosphorylation of ERK and c-RAF. Our data suggest that S100A9 signaling contributes to the progression of smoke-induced and age-related COPD.

Elevated levels of calpain 14 in nasal tissue in chronic rhinosinusitis.

Sinusitis is a common condition associated with inflammation in the sinuses and nasal mucosa. Calpain 14 is highly expressed in the nasal tissues of sinusitis subjects. Calpain 14 is associated with epithelial barrier disruption. https://bit.ly/3fyAwVO.

SIRT7 deficiency suppresses inflammation, induces EndoMT, and increases vascular permeability in primary pulmonary endothelial cells.

Acute lung injury (ALI), a common condition in critically ill patients, has limited treatments and high mortality. Aging is a risk factor for ALI. Sirtuins (SIRTs), central regulators of the aging process, decrease during normal aging and in aging-related diseases. We recently showed decreased SIRT7 expression in lung tissues and fibroblasts from patients with pulmonary fibrosis compared to controls. To gain insight into aging-related mechanisms in ALI, we investigated the effects of SIRT7 depletion on lipopolysaccharide (LPS)-induced inflammatory responses and endothelial barrier permeability in human primary pulmonary endothelial cells. Silencing SIRT7 in pulmonary artery or microvascular endothelial cells attenuated LPS-induced increases in ICAM1, VCAM1, IL8, and IL6 and induced endomesenchymal transition (EndoMT) with decreases in VE-Cadherin and PECAM1 and increases in collagen, alpha-smooth muscle actin, TGFß receptor 1, and the transcription factor Snail. Loss of endothelial adhesion molecules was accompanied by increased F-actin stress fibers and increased endothelial barrier permeability. Together, these results show that an aging phenotype induced by SIRT7 deficiency promotes EndoMT with impaired inflammatory responses and dysfunction of the lung vascular barrier.

Zika Virus Circulation in Mali.

The circulation of Zika virus (ZIKV) in Mali has not been clearly characterized. Therefore, we conducted a serologic survey of 793 asymptomatic volunteers >15 years of age (2016), and 637 blood donors (2013) to assess the seroprevalence of ZIKV infection in 2 ecoclimatic regions of Mali, tropical savannah and warm semiarid region, using ELISA and seroneutralization assays. The overall seroprevalence was ≈12% and increased with age, with no statistical difference between male and female participants. In the warm semiarid study sites we detected immunological markers of an outbreak that occurred in the late 1990s in 18% (95% CI 13%-23%) of participants. In tropical savannah sites, we estimated a low rate of endemic transmission, with 2.5% (95% CI 2.0%-3.1%) of population infected by ZIKV annually. These data demonstrate the circulation of ZIKV in Mali and provide evidence of a previously unidentified outbreak that occurred in the late 1990s.

Decreased surfactant lipids correlate with lung function in chronic obstructive pulmonary disease (COPD).

Smoke exposure is known to decrease total pulmonary surfactant and alter its composition, but the role of surfactant in chronic obstructive pulmonary disease (COPD) remains unknown. We aimed to analyze the compositional changes in the surfactant lipidome in COPD and identify specific lipids associated with pulmonary function decline. Bronchoalveolar lavage (BAL) fluid was obtained from 12 former smokers with COPD and 5 non-smoking, non-asthmatic healthy control volunteers. Lipids were extracted and analyzed by liquid chromatography and mass spectrometry. Pulmonary function data were obtained by spirometry, and correlations of lung function with lipid species were determined. Wild-type C57BL/6 mice were exposed to 6 months of second-hand smoke in a full-body chamber. Surfactant lipids were decreased by 60% in subjects with COPD. All phospholipid classes were dramatically decreased, including ether phospholipids, which have not been studied in pulmonary surfactant. Availability of phospholipid, cholesterol, and sphingomyelin in BAL strongly correlated with pulmonary function and this was attributable to specific lipid species of phosphatidylcholine with surface tension reducing properties, and of phosphatidylglycerol with antimicrobial roles, as well as to other less studied lipid species. Mice exposed to smoke for six months recapitulated surfactant lipidomic changes observed in human subjects with COPD. In summary, we show that the surfactant lipidome is substantially altered in subjects with COPD, and decreased availability of phospholipids correlated with decreased pulmonary function. Further investigation of surfactant alterations in COPD would improve our understanding of its physiopathology and reveal new potential therapeutic targets.

Airway Resistance Caused by Sphingomyelin Synthase 2 Insufficiency in Response to Cigarette Smoke.

Sphingomyelin synthase is responsible for the production of sphingomyelin (SGM), the second most abundant phospholipid in mammalian plasma, from ceramide, a major sphingolipid. Knowledge of the effects of cigarette smoke on SGM production is limited. In the present study, we examined the effect of chronic cigarette smoke on sphingomyelin synthase (SGMS) activity and evaluated how the deficiency of Sgms2, one of the two isoforms of mammalian SGMS, impacts pulmonary function. Sgms2-knockout and wild-type control mice were exposed to cigarette smoke for 6 months, and pulmonary function testing was performed. SGMS2-dependent signaling was investigated in these mice and in human monocyte-derived macrophages of nonsmokers and human bronchial epithelial (HBE) cells isolated from healthy nonsmokers and subjects with chronic obstructive pulmonary disease (COPD). Chronic cigarette smoke reduces SGMS activity and Sgms2 gene expression in mouse lungs. Sgms2-deficient mice exhibited enhanced airway and tissue resistance after chronic cigarette smoke exposure, but had similar degrees of emphysema, compared with smoke-exposed wild-type mice. Sgms2-/- mice had greater AKT phosphorylation, peribronchial collagen deposition, and protease activity in their lungs after smoke inhalation. Similarly, we identified reduced SGMS2 expression and enhanced phosphorylation of AKT and protease production in HBE cells isolated from subjects with COPD. Selective inhibition of AKT activity or overexpression of SGMS2 reduced the production of several matrix metalloproteinases in HBE cells and monocyte-derived macrophages. Our study demonstrates that smoke-regulated Sgms2 gene expression influences key COPD features in mice, including airway resistance, AKT signaling, and protease production.

Targeting c-Src Reverses Accelerated GPX-1 mRNA Decay in Chronic Obstructive Pulmonary Disease Airway Epithelial Cells.

Enhanced expression of the cellular antioxidant glutathione peroxidase (GPX)-1 prevents cigarette smoke-induced lung inflammation and tissue destruction. Subjects with chronic obstructive pulmonary disease (COPD), however, have decreased airway GPX-1 levels, rendering them more susceptible to disease onset and progression. The mechanisms that downregulate GPX-1 in the airway epithelium in COPD remain unknown. To ascertain these factors, analyses were conducted using human airway epithelial cells isolated from healthy subjects and human subjects with COPD and lung tissue from control and cigarette smoke-exposed A/J mice. Tyrosine phosphorylation modifies GPX-1 expression and cigarette smoke activates the tyrosine kinase c-Src. Therefore, studies were conducted to evaluate the role of c-Src on GPX-1 levels in COPD. These studies identified accelerated GPX-1 mRNA decay in COPD airway epithelial cells. Targeting the tyrosine kinase c-Src with siRNA inhibited GPX-1 mRNA degradation and restored GPX-1 protein levels in human airway epithelial cells. In contrast, silencing the tyrosine kinase c-Abl, or the transcriptional activator Nrf2, had no effect on GPX-1 mRNA stability. The chemical inhibitors for c-Src (saracatinib and dasanitib) restored GPX-1 mRNA levels and GPX-1 activity in COPD airway cells in vitro. Similarly, saracatinib prevented the loss of lung Gpx-1 expression in response to chronic smoke exposure in vivo. Thus, this study establishes that the decreased GPX-1 expression that occurs in COPD lungs is at least partially due to accelerated mRNA decay. Furthermore, these findings show that targeting c-Src represents a potential therapeutic approach to augment GPX-1 responses and counter smoke-induced lung disease.