1.
Gio-Batta, Monica, et al.
(författare)
Low Concentration of Fecal Valeric Acid at 1 Year of Age Is Linked with Eczema and Food Allergy at 13 Years of Age : Findings from a Swedish Birth Cohort
2022
Ingår i: International Archives of Allergy and Immunology. - : S. Karger. - 1018-2438 .- 1423-0097. ; , s. 398-408
Tidskriftsartikel (refereegranskat) abstract
Background: Short-chain fatty acids (SCFAs) are abundant bacterial metabolites in the gut, with immunomodulatory properties. Hence, they may influence allergy development. Previous studies have linked fecal SCFA pattern during infancy with allergy. However, the association of SCFAs to allergic outcomes in adolescence is not well established. Here, we examined how the fecal SCFA pattern at 1 year of age related to allergy at 13 years of age.Methods: Levels of 8 SCFAs in fecal samples collected at 1 year of age from 110 children were quantified using gas chromatography. The same individuals were evaluated at 13 years of age for allergic symptoms, allergy diagnosis and allergy medication by questionnaire, and for sensitization using skin prick test against egg, milk, fish, wheat and soy, cat, dog, horse, birch, and timothy grass.Results: The concentration of fecal valeric acid at 1 year of age was inversely associated with eczema at 13 years of age (OR 0.6, 95% CI: 0.4-1.0, p = 0.049) and showed a trend for inverse association with food allergy at 13 years of age (OR 0.6, 95% CI: 0.4-1.0, p = 0.057). In a sub-group analysis of children with eczema at 1 year of age, a higher concentration of fecal valeric acid was linked with reduced risk of their eczema remaining at 13 years of age (OR 0.2, 95% CI: 0.0-1.5), although this latter analysis did not reach statistical significance (p = 0.12).Conclusions: Our findings lend further support to the notion of early childhood as a critical period when allergy may be programmed via the gut microbiota. Higher levels of fecal valeric acid may be characteristic of a protective gut microbiota and/or actively contribute to protection from eczema and food allergy.
2.
Venkatakrishnan, Vignesh, 1987, et al.
(författare)
Novel inhibitory effect of galectin-3 on the respiratory burst induced by Staphylococcus aureus in human neutrophils
2023
Ingår i: Glycobiology. - : OXFORD UNIV PRESS INC. - 1460-2423 .- 0959-6658. ; 33:6, s. 503-511
Tidskriftsartikel (refereegranskat) abstract
Among the responders to microbial invasion, neutrophils represent the earliest and perhaps the most important immune cells that contribute to host defense with the primary role to kill invading microbes using a plethora of stored anti-microbial molecules. One such process is the production of reactive oxygen species (ROS) by the neutrophil enzyme complex NADPH-oxidase, which can be assembled and active either extracellularly or intracellularly in phagosomes (during phagocytosis) and/or granules (in the absence of phagocytosis). One soluble factor modulating the interplay between immune cells and microbes is galectin-3 (gal-3), a carbohydrate-binding protein that regulates a wide variety of neutrophil functions. Gal-3 has been shown to potentiate neutrophil interaction with bacteria, including Staphylococcus aureus, and is also a potent activator of the neutrophil respiratory burst, inducing large amounts of granule-localized ROS in primed cells. Herein, the role of gal-3 in regulating S. aureus phagocytosis and S. aureus-induced intracellular ROS was analyzed by imaging flow cytometry and luminol-based chemiluminescence, respectively. Although gal-3 did not interfere with S. aureus phagocytosis per se, it potently inhibited phagocytosis-induced intracellular ROS production. Using the gal-3 inhibitor GB0139 (TD139) and carbohydrate recognition domain of gal-3 (gal-3C), we found that the gal-3-induced inhibitory effect on ROS production was dependent on the carbohydrate recognition domain of the lectin. In summary, this is the first report of an inhibitory role of gal-3 in regulating phagocytosis-induced ROS production.
3.
Khoomrung, Sakda, 1978, et al.
(författare)
Metabolic Profiling and Compound-Class Identification Reveal Alterations in Serum Triglyceride Levels in Mice Immunized with Human Vaccine Adjuvant Alum
2020
Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3907 .- 1535-3893. ; 19:1, s. 269-278
Tidskriftsartikel (refereegranskat) abstract
Alum has been widely used as an adjuvant for human vaccines; however, the impact of Alum on host metabolism remains largely unknown. Herein, we applied mass spectrometry (MS) (liquid chromatography-MS)-based metabolic and lipid profiling to monitor the effects of the Alum adjuvant on mouse serum at 6, 24, 72, and 168 h post-vaccination. We propose a new strategy termed subclass identification and annotation for metabolomics for class-wise identification of untargeted metabolomics data generated from high-resolution MS. Using this approach, we identified and validated the levels of several lipids in mouse serum that were significantly altered following Alum administration. These lipids showed a biphasic response even 168 h after vaccination. The majority of the lipids were triglycerides (TAGs), where TAGs with long-chain unsaturated fatty acids (FAs) decreased at 24 h and TAGs with short-chain FAs decreased at 168 h. To our knowledge, this is the first report on the impact of human vaccine adjuvant Alum on the host metabolome, which may provide new insights into the mechanism of action of Alum. ©
4.
Sävman, Karin, 1960, et al.
(författare)
Galectin-3 Modulates Microglia Inflammation in vitro but Not Neonatal Brain Injury in vivo under Inflammatory Conditions
2021
Ingår i: Developmental Neuroscience. - : S. Karger AG. - 0378-5866 .- 1421-9859. ; 43:5, s. 296-311
Tidskriftsartikel (refereegranskat) abstract
Microglia may contribute to injury but may also have neuroprotective properties. Galectin-3 has immunomodulatory properties that may affect the microglia phenotype and subsequent development of injury. Galectin-3 contributes to experimental hypoxic-ischemic (HI) injury in the neonatal brain, but it is unclear if galectin-3 has similar effects on infectious and sterile inflammation. Thus, we investigated the effect of galectin-3 on microglia in vitro under normal as well as infectious and sterile inflammatory conditions, and the effect of galectin-3 on neonatal brain injury following an infectious challenge in vivo. Conditions mimicking infectious or sterile inflammation were evaluated in primary microglia cell cultures from newborn mice, using LPS (10 ng/mL) and TNF-alpha (100 ng/mL). The response to galectin-3 was tested alone or together with LPS or TNF-alpha. Supernatants were collected 24 h after treatment and analyzed for 23 inflammatory mediators including pro- and anti-inflammatory cytokines and chemokines using multiplex protein analysis, as well as ELISA for MCP-1 and insulin-like growth factor (IGF)-1. Phosphorylation of proteins (AKT, ERK1/2, I kappa B-alpha, JNK, and p38) was determined in microglia cells. Neonatal brain injury was induced by a combination of LPS and HI (LPS + HI) in postnatal day 9 transgenic mice lacking functional galectin-3 and wild-type controls. LPS and TNF-alpha induced pro-inflammatory (9/11 vs. 9/10) and anti-inflammatory (6/6 vs. 2/6) cytokines, as well as chemokines (6/6 vs. 4/6) in a similar manner, except generally lower amplitude of the TNF-alpha-induced response. Galectin-3 alone had no effect on any of the proteins analyzed. Galectin-3 reduced the LPS- and TNF-alpha-induced microglia response for cytokines, chemokines, and phosphorylation of I kappa B-alpha. LPS decreased baseline IGF-1 levels, and the levels were restored by galectin-3. Brain injury or microglia response after LPS + HI was not affected by galectin-3 deficiency. Galectin-3 has no independent effect on microglia but modulates inflammatory activation in vitro. The effect was similar under infectious and sterile inflammatory conditions, suggesting that galectin-3 regulates inflammation not just by binding to LPS or toll-like receptor-4. Galectin-3 restores IGF-1 levels reduced by LPS-induced inflammation, suggesting a potential protective effect on infectious injury. However, galectin-3 deficiency did not affect microglia activation and was not beneficial in an injury model encompassing an infectious challenge.
5.
Svahn, Sara L, et al.
(författare)
Dietary polyunsaturated fatty acids increase survival and decrease bacterial load during septic S. aureus infection, and improve neutrophil function in mice
2015
Ingår i: Infection and Immunity. - 0019-9567 .- 1098-5522. ; 83:2, s. 514-21
Tidskriftsartikel (refereegranskat) abstract
Severe infection, including sepsis, is an increasing clinical problem that causes prolonged morbidity and substantial mortality. At present, antibiotics are essentially the only pharmacological treatment for sepsis. The incidence of resistance to antibiotics is increasing and it is therefore critical to find new therapies for sepsis. Staphylococcus aureus (S. aureus) is a major cause of septic mortality. Neutrophils play an important role in the defense against bacterial infections. We have shown that a diet with high levels of dietary saturated fatty acids decreases survival in septic mice, but the mechanisms behind remain elusive. The aim of the present study was to investigate how the differences in dietary fat composition affect survival and bacterial load after experimental septic infection and neutrophil function in uninfected mice. We found that, after S. aureus infection, mice fed polyunsaturated high fat diet (HFD/P) for 8 weeks had increased survival and decreased bacterial load during sepsis compared with mice fed saturated high fat diet (HFD/S), and similar to that of mice fed low fat diet (LFD). Uninfected mice fed HFD/P had increased frequency of neutrophils in bone marrow compared with mice fed HFD/S. In addition, mice fed HFD/P had a higher frequency of neutrophils recruited to the site of inflammation in response to peritoneal injection of thioglycollate compared with HFD/S. Differences between the proportion of dietary protein and carbohydrate did not affect septic survival at all. In conclusion, polyunsaturated dietary fat increased both survival and efficiency of bacterial clearance during septic S. aureus infection. Moreover, this diet increased the frequency and chemotaxis of neutrophils, key components of the immune response to S. aureus infections.
6.
Abarenkov, Kessy, et al.
(författare)
Annotating public fungal ITS sequences from the built environment according to the MIxS-Built Environment standard – a report from a May 23-24, 2016 workshop (Gothenburg, Sweden)
2016
Ingår i: MycoKeys. - : Pensoft Publishers. - 1314-4057 .- 1314-4049. ; 16, s. 1-15
Tidskriftsartikel (refereegranskat) abstract
Recent molecular studies have identified substantial fungal diversity in indoor environments. Fungi and fungal particles have been linked to a range of potentially unwanted effects in the built environment, including asthma, decay of building materials, and food spoilage. The study of the built mycobiome is hampered by a number of constraints, one of which is the poor state of the metadata annotation of fungal DNA sequences from the built environment in public databases. In order to enable precise interrogation of such data – for example, “retrieve all fungal sequences recovered from bathrooms” – a workshop was organized at the University of Gothenburg (May 23-24, 2016) to annotate public fungal barcode (ITS) sequences according to the MIxS-Built Environment annotation standard (http://gensc.org/mixs/). The 36 participants assembled a total of 45,488 data points from the published literature, including the addition of 8,430 instances of countries of collection from a total of 83 countries, 5,801 instances of building types, and 3,876 instances of surface-air contaminants. The results were implemented in the UNITE database for molecular identification of fungi (http://unite.ut.ee) and were shared with other online resources. Data obtained from human/animal pathogenic fungi will furthermore be verified on culture based metadata for subsequent inclusion in the ISHAM-ITS database (http://its.mycologylab.org).
7.
Marklund, Emelie, et al.
(författare)
Serum-IgG responses to SARS-CoV-2 after mild and severe COVID-19 infection and analysis of IgG non-responders.
2020
Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 15:10
Tidskriftsartikel (refereegranskat) abstract
To accurately interpret COVID-19 seroprevalence surveys, knowledge of serum-IgG responses to SARS-CoV-2 with a better understanding of patients who do not seroconvert, is imperative. This study aimed to describe serum-IgG responses to SARS-CoV-2 in a cohort of patients with both severe and mild COVID-19, including extended studies of patients who remained seronegative more than 90 days post symptom onset.SARS-CoV-2-specific IgG antibody levels were quantified using two clinically validated and widely used commercial serological assays (Architect, Abbott Laboratories and iFlash 1800, YHLO), detecting antibodies against the spike and nucleocapsid proteins.Forty-seven patients (mean age 49 years, 38% female) were included. All (15/15) patients with severe symptoms and 29/32 (90.6%) patients with mild symptoms of COVID-19 developed SARS-CoV-2-specific IgG antibodies in serum. Time to seroconversion was significantly shorter (median 11 vs. 22 days, P = 0.04) in patients with severe compared to mild symptoms. Of the three patients without detectable IgG-responses after >90 days, all had detectable virus-neutralizing antibodies and in two, spike-protein receptor binding domain-specific IgG was detected with an in-house assay. Antibody titers were preserved during follow-up and all patients who seroconverted, irrespective of the severity of symptoms, still had detectable IgG levels >75 days post symptom onset.Patients with severe COVID-19 both seroconvert earlier and develop higher concentrations of SARS-CoV-2-specific IgG than patients with mild symptoms. Of those patients who not develop detectable IgG antibodies, all have detectable virus-neutralizing antibodies, suggesting immunity. Our results showing that not all COVID-19 patients develop detectable IgG using two validated commercial clinical methods, even over time, are vital for the interpretation of COVID-19 seroprevalence surveys.
8.
Dahlstrand Rudin, Agnes, et al.
(författare)
Porphyromonas gingivalis Produce Neutrophil Specific Chemoattractants Including Short Chain Fatty Acids
2021
Ingår i: Frontiers in cellular and infection microbiology. - : Frontiers Media SA. - 2235-2988. ; 10
Tidskriftsartikel (refereegranskat) abstract
Neutrophil migration from blood to tissue-residing microbes is governed by a series of chemoattractant gradients of both endogenous and microbial origin. Periodontal disease is characterized by neutrophil accumulation in the gingival pocket, recruited by the subgingival biofilm consisting mainly of gram-negative, anaerobic and proteolytic species such as Porphyromonas gingivalis. The fact that neutrophils are the dominating cell type in the gingival pocket suggests that neutrophil-specific chemoattractants are released by subgingival bacteria, but characterization of chemoattractants released by subgingival biofilm species remains incomplete. In the present study we characterized small (< 3 kDa) soluble chemoattractants released by growing P. gingivalis, and show that these are selective for neutrophils. Most neutrophil chemoattractant receptors are expressed also by mononuclear phagocytes, the free fatty acid receptor 2 (FFAR2) being an exception. In agreement with the selective neutrophil recruitment, the chemotactic activity found in P. gingivalis supernatants was mediated in part by a mixture of short chain fatty acids (SCFAs) that are recognized by FFAR2, and other leukocytes (including monocytes) did not respond to SCFA stimulation. Although SCFAs, produced by bacterial fermentation of dietary fiber in the gut, has previously been shown to utilize FFAR2, our data demonstrate that the pronounced proteolytic metabolism employed by P. gingivalis (and likely also other subgingival biofilm bacteria associated with periodontal diseases) may result in the generation of SCFAs that attract neutrophils to the gingival pocket. This finding highlights the interaction between SCFAs and FFAR2 in the context of P. gingivalis colonization during periodontal disease, but may also have implications for other inflammatory pathologies involving proteolytic bacteria.
9.
Mukherjee, Sourav P., et al.
(författare)
Graphene Oxide Elicits Membrane Lipid Changes and Neutrophil Extracellular Trap Formation
2018
Ingår i: Chem. - : Elsevier BV. - 2451-9294 .- 2451-9308. ; 4:2, s. 334-358
Tidskriftsartikel (refereegranskat) abstract
Understanding the biological interactions of graphene-based materials is important for the safe use of these materials. Previous studies have explored the interaction between graphene oxide (GO) and macrophages but not the impact of GO on neutrophils, key cells of the immune system. Here, we synthesized GO sheets with differing lateral dimensions and showed by using an array of analytical and imaging techniques, including transmission and scanning electron microscopy, confocal microscopy, and time-of-flight secondary ion mass spectroscopy (ToF-SIMS), that GO elicited the formation of neutrophil extracellular traps (NETs). ToF-SIMS revealed pronounced perturbations of plasma membrane lipids, including a decrease in cholesterol and increased levels of oxidized cholesterol species. The induction of NETs was size dependent and associated with the production of mitochondrial reactive oxygen species and calcium influx. Importantly, antioxidant treatment reduced the production of NETs. These studies provide evidence that a previously undescribed biological effect of GO manifests through direct effects on membrane lipids. Graphene oxide (GO) is being investigated for various biomedical applications. Understanding the interactions between GO and living cells is of critical importance for the safe use of these materials in patients. In the present study, we identified effects of GO on neutrophils, the most common type of white blood cell. We first synthesized GO sheets of different sizes and carefully characterized the materials. Then, using various analytical and imaging techniques, we found that GO triggered so-called neutrophil extracellular traps or NETs. NETs are normally deployed by neutrophils to capture and destroy pathogens. We were able to show that GO caused significant changes in the lipid composition of the neutrophil cell membrane, whereby the oxidation of cholesterol set into motion a cascade of intracellular events leading to the formation of NETs. These studies show that GO acts directly on the neutrophil cell membrane and leads to the activation of a conserved anti-pathogen response. Graphene oxide (GO) is a promising material for a variety of biomedical and other applications. The increasing use of GO necessitates careful assessment of potential health hazards. Using primary neutrophils as a model, Mukherjee et al. show that GO elicits neutrophil extracellular traps. Furthermore, by using ToF-SIMS, the authors noted pronounced perturbations of plasma membrane lipids in cells exposed to GO.
10.
Trybala, Edward, 1955, et al.
(författare)
Herpes Simplex Virus Type 2 Mucin-Like Glycoprotein mgG Promotes Virus Release from the Surface of Infected Cells
2021
Ingår i: Viruses. - : MDPI AG. - 1999-4915. ; 13:5
Tidskriftsartikel (refereegranskat) abstract
The contribution of virus components to liberation of herpes simplex virus type 2 (HSV-2) progeny virions from the surface of infected cells is poorly understood. We report that the HSV-2 mutant deficient in the expression of a mucin-like membrane-associated glycoprotein G (mgG) exhibited defect in the release of progeny virions from infected cells manifested by similar to 2 orders of magnitude decreased amount of infectious virus in a culture medium as compared to native HSV-2. Electron microscopy revealed that the mgG deficient virions were produced in infected cells and present at the cell surface. These virions could be forcibly liberated to a nearly native HSV-2 level by the treatment of cells with glycosaminoglycan (GAG)-mimicking oligosaccharides. Comparative assessment of the interaction of mutant and native virions with surface-immobilized chondroitin sulfate GAG chains revealed that while the mutant virions associated with GAGs similar to fourfold more extensively, the lateral mobility of bound virions was much poorer than that of native virions. These data indicate that the mgG of HSV-2 balances the virus interaction with GAG chains, a feature critical to prevent trapping of the progeny virions at the surface of infected cells.
