Phospholipids: "greasing the wheels" of humoral immunity

Immunomodulatory effects and multi-omics analysis of Codonopsis Pilosula Extract in septic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Codonopsis Pilosula (CP), as a well-known traditional Chinese medicine (TCM) with medicinal and edible herb, is one of the most representative tonic Chinese herbal medicine. It has been widely used for regulating immune function with hardly any adverse effects in clinical practice.

AIM OF THE STUDY

This study aimed to elucidate the immunomodulatory effect and to explore probable mechanism of Codonopsis Pilosula Extract (CPE) in septic rats.

MATERIALS AND METHODS

The model of septic rat was established by cecal ligation and perforation (CLP). The thymus index, spleen index and cerebral index were calculated. Histological changes were observed by Hematoxylin-eosin (HE). The positive expression of CD4+ T cells was determined in the thymus and spleen by immunohistochemical (IHC). The expression level of 24 h CD4 was corroborated by real-time quantitative polymerase chain reaction (RT-QPCR). Infectious factors, immune factors and inflammatory factors were determined by enzyme-linked immunosorbent assay (ELISA). Blood cells were detected by automatic biochemical analyzer. The metabolite changes and gene expression levels, the potential targets and pathways of CPE in regulating immune function of thymus were analyzed by integrative analysis of transcriptomic and metabolomic methods.

RESULTS

High dose of CPE increased the thymus index and spleen index of septic rats at different stages, and the brain index at different stages could be increased at medium dose and high dose. Medium and high doses of CPE reduced the pathological changes of thymus, spleen and brain tissue. CPE promoted the expression levels of CD4 in the thymus and spleen. CPE improved the levels of red blood cells (RBC), lymphocytes (LYM) and hemoglobin (HGB), and decreased the levels of neutrophils (NEUT), NLR (NEUT/LYM) and PLR (PLT/LYM). CPE dynamically regulated the levels of white blood cells (WBC) and PLT (platelet). CPE dynamically regulated the expression levels of infectious factors, immune factors, and inflammatory factors related to disease severity.

CONCLUSION

CPE has the ability to dynamically modulate the expression levels of infectious factors, immune factors, and inflammatory factors related to disease severity, and alleviate the damages of immune organs. The research has provided a global view of the integration of metabolomics and transcriptomics to elucidate the immunomodulatory effects and mechanisms of CPE. CPE could affect a series of biological processes in glycerophospholipid metabolism by interfering with the B cell receptor (BCR) signaling pathway in the thymus, to maintain immune homeostasis of septic rats on the whole, especially humoral immunity.

Magnitude of obesity alone does not alter the alveolar lipidome

Obesity may lead to pulmonary dysfunction through complex and incompletely understood cellular and biochemical effects. Altered lung lipid metabolism has been identified as a potential mechanism of lung dysfunction in obesity. Although murine models of obesity demonstrate changes in pulmonary surfactant phospholipid composition and function, data in humans are lacking. We measured untargeted shotgun lipidomes in two bronchoalveolar lavages (BALs) from apical and anteromedial pulmonary subsegments of 14 adult subjects (7 males and 7 females) with body mass indexes (BMIs) ranging from 24.3 to 50.9 kg/m2. The lipidome composition was characterized at the class, species, and fatty acyl/alkyl level using total lipid molecular ion signal intensities normalized to BAL protein concentration and epithelial lining fluid volumes. Multivariate analyses were conducted to identify potential changes with increasing BMI. The alveolar lipidomes contained the expected composition of surfactant-associated phospholipids, sphingolipids, and sterols in addition to cardiolipin and intracellular signaling lipid species. No significant differences in lipidomes were detected between the two BAL regions. Though a small number of lipid species were associated with BMI in multivariate analyses, no robust differences in lipidome composition or specific lipid species were identified over the range of body habitus. The magnitude of obesity alone does not substantially alter the alveolar lipidome in patients without lung disease. Differences in lung function in patients with obesity and no lung disease are unlikely related to changes in alveolar lipid composition.NEW & NOTEWORTHY Altered lung lipid metabolism has been identified as a potential mechanism of lung dysfunction in obesity, but data in humans are lacking. We measured the alveolar lipidome in bronchoalveolar lavages from subjects with healthy lungs with a wide range of body mass index. There were no differences in lipidome composition in association with the magnitude of obesity. In patients with healthy lungs, obesity alone does not alter the alveolar lipidome.

The lipidome of posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) can develop after trauma exposure. Some studies report that women develop PTSD at twice the rate of men, despite greater trauma exposure in men. Lipids and their metabolites (lipidome) regulate a myriad of key biological processes and pathways such as membrane integrity, oxidative stress, and neuroinflammation in the brain by maintaining neuronal connectivity and homeostasis. In this study, we analyzed the lipidome of 40 individuals with PTSD and 40 trauma-exposed non-PTSD individuals. Plasma samples were analyzed for lipidomics using Quadrupole Time-of-Flight (QToF) mass spectrometry. Additionally, ~ 90 measures were collected, on sleep, mental and physical health indices. Sleep quality worsened as PTSD severity increased in both sexes. The lipidomics analysis identified a total of 348 quantifiable known lipid metabolites and 1951 lipid metabolites that are yet unknown; known metabolites were part of 13 classes of lipids. After adjusting for sleep quality, in women with PTSD, only one lipid subclass, phosphatidylethanolamine (PE) was altered, whereas, in men with PTSD, 9 out of 13 subclasses were altered compared to non-PTSD women and men, respectively. Severe PTSD was associated with 22% and 5% of altered lipid metabolites in men and women, respectively. Of the changed metabolites, only 0.5% measures (2 PEs and cholesterol) were common between women and men with PTSD. Several sphingomyelins, PEs, ceramides, and triglycerides were increased in men with severe PTSD. The triglycerides and ceramide metabolites that were most highly increased were correlated with cholesterol metabolites and systolic blood pressure in men but not always in women with PTSD. Alterations in triglycerides and ceramides are linked with cardiac health and metabolic function in humans. Thus, disturbed sleep and higher weight may have contributed to changes in the lipidome found in PTSD.

UHPLC-MS/MS -based Untargeted Lipidomics Analysis of Septic Patients

BACKGROUND

Lipids take part in many pathophysiological processes of sepsis, thus, the variation of lipid composition may have clue on the severity and pathogen to sepsis. The objective of our study is to expand the profile of lipid compositions and screen potential biomarkers in intensive care unit (ICU) patients with sepsis.

METHODS

Patients admitted to the ICU clearly diagnosed with celiac sepsis were included in this prospective study. Age-matched healthy participants from the Physical Examination Center were used as the control group. Blood samples were obtained from patients within the first 12 h of admission. We analysed different components of the lipid metabolism between the sepsis patients and controls and described characteristic features during sepsis.

RESULTS

Thirty patients with celiac sepsis and 30 sex- and age-matched healthy controls were enrolled in this study. The lipid metabolic signature was obviously different between the sepsis patients and healthy controls and was mostly downregulated in sepsis patients. We identified 65 lipid species. Sixty-four lipid molecules were found to be significantly downregulated in sepsis patients, and only the level of one phosphatidylethanolamine (PE) molecule, PE (34:2) was higher in the sepsis patients with sepsis group comparing with the control group. The analysis of metabolic pathway illustrated the different lipid molecules were closely related to PC、LPC、and PE.

CONCLUSION

Sepsis contributes to impaired expression of most lipids, which mainly result in the disorder of glycerolipid metabolic pathway, including PC、LPC、and PE.

Identification and localization of morphological feature-specific metabolites in Reynoutria multiflora roots

Reynoutria multiflora roots are a classical herbal medicine with unique nourishing therapeutic effects. Anomalous vascular bundle (AVB) forming "cloudy brocade patterns" is a typical morphological feature of R. multiflora roots and has been empirically linked to its quality classification. However, scientific evidence, especially for AVB-specific specialised metabolites, has not been comprehensively revealed thus far. Herein, desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) analysis was applied to carry out an in situ analysis of specialised metabolites distributed specifically at the AVB and cork of R. multiflora roots. To enlarge the scope of compounds by DESI detection, various solvent systems including acetone, acetonitrile, methanol, and water were used to assist in the discoveries of 40 specialised metabolites with determined localization. A series of bioactive constituents including stilbenes, flavonoids, anthraquinones, alkaloids, and naphthalenes were found specifically around the brocade patterns. Notably, phospholipids were detected from R. multiflora roots by in situ analysis for the first time and were found mainly in the phloem of AVB (PAB). This is the first study to use gradient solvent systems in DESI-MSI analysis to locate the specialised metabolites distribution. The discovery of feature-specific compounds will bridge the empirical identification to precision quality control of R. multiflora roots.

Internal extractive electrospray ionization mass spectrometry for investigating the phospholipid dysregulation induced by perfluorooctanoic acid in Nile tilapia

Direct profiling of endogenous biomolecules in tissue samples is considered to be a promising approach to investigate metabolic-related toxicity in organisms induced by emerging pollutants.

Decreased plasma phospholipid concentrations and increased acid sphingomyelinase activity are accurate biomarkers for community-acquired pneumonia

Background

There continues to be a great need for better biomarkers and host-directed treatment targets for community-acquired pneumonia (CAP). Alterations in phospholipid metabolism may constitute a source of small molecule biomarkers for acute infections including CAP. Evidence from animal models of pulmonary infections and sepsis suggests that inhibiting acid sphingomyelinase (which releases ceramides from sphingomyelins) may reduce end-organ damage.

Methods

We measured concentrations of 105 phospholipids, 40 acylcarnitines, and 4 ceramides, as well as acid sphingomyelinase activity, in plasma from patients with CAP (n = 29, sampled on admission and 4 subsequent time points), chronic obstructive pulmonary disease exacerbation with infection (COPD, n = 13) as a clinically important disease control, and 33 age- and sex-matched controls.

Results

Phospholipid concentrations were greatly decreased in CAP and normalized along clinical improvement. Greatest changes were seen in phosphatidylcholines, followed by lysophosphatidylcholines, sphingomyelins and ceramides (three of which were upregulated), and were least in acylcarnitines. Changes in COPD were less pronounced, but also differed qualitatively, e.g. by increases in selected sphingomyelins. We identified highly accurate biomarkers for CAP (AUC ≤ 0.97) and COPD (AUC ≤ 0.93) vs. Controls, and moderately accurate biomarkers for CAP vs. COPD (AUC ≤ 0.83), all of which were phospholipids. Phosphatidylcholines, lysophosphatidylcholines, and sphingomyelins were also markedly decreased in S. aureus-infected human A549 and differentiated THP1 cells. Correlations with C-reactive protein and procalcitonin were predominantly negative but only of mild-to-moderate extent, suggesting that these markers reflect more than merely inflammation. Consistent with the increased ceramide concentrations, increased acid sphingomyelinase activity accurately distinguished CAP (fold change = 2.8, AUC = 0.94) and COPD (1.75, 0.88) from Controls and normalized with clinical resolution.

Conclusions

The results underscore the high potential of plasma phospholipids as biomarkers for CAP, begin to reveal differences in lipid dysregulation between CAP and infection-associated COPD exacerbation, and suggest that the decreases in plasma concentrations are at least partially determined by changes in host target cells. Furthermore, they provide validation in clinical blood samples of acid sphingomyelinase as a potential treatment target to improve clinical outcome of CAP.

Validating loci associated with bovine respiratory disease complex in pre-weaned Holstein calves

Bovine respiratory disease (BRD) is considered one of the most economically important diseases in the cattle industry. Ultimately, the selection of cattle that are less susceptible to disease will allow producers to reduce the prevalence of BRD and lessen its economic impact. The objective of this study was to validate previously identified loci associated with susceptibility to BRD in an independent population of 140 pre-weaned Holstein calves from Wisconsin (WI). Using the McGuirk health scoring system, calves were classified as either clinically affected with BRD (n = 35) or healthy (n = 105). Additive genotypic tests were performed for genomic regions previously associated with susceptibility to BRD in calves from California (CA) and New Mexico (NM). Using this method, 4 loci (P < 0.01) consisting of 10 SNP were validated in the WI population, including 2 loci from CA, 1 locus from NM, and 1 locus from a combined CA + NM population. Most of the positional candidate genes and transcription factor binding site motifs associated with these loci have functions related to innate and adaptive immune responses. The validation of loci associated with susceptibility to BRD in independent populations allows producers to more reliably select cattle that are less susceptible to BRD, improving animal welfare, decreasing the annual revenue losses, and lowering the prevalence of the disease.

TTC7A: Steward of Intestinal Health

The increasing incidence of pediatric inflammatory bowel disease, coupled with the efficiency of whole-exome sequencing, has led to the identification of tetratricopeptide repeat domain 7A (TTC7A) as a steward of intestinal health. TTC7A deficiency is an autosomal-recessively inherited disease. In the 5 years since the original description, more than 50 patients with more than 20 distinct disease-causing TTC7A mutations have been identified. Patients show heterogenous intestinal and immunologic disease manifestations, including but not limited to multiple intestinal atresias, very early onset inflammatory bowel disease, loss of intestinal architecture, apoptotic enterocolitis, combined immunodeficiency, and various extraintestinal features related to the skin and/or hair. The focus of this review is to highlight trends in patient phenotypes and to consolidate functional data related to the role of TTC7A in maintaining intestinal homeostasis. TTC7A deficiency is fatal in approximately two thirds of patients, and, as more patients continue to be discovered, elucidating the comprehensive role of TTC7A could show druggable targets that may benefit the growing cohort of individuals suffering from inflammatory bowel disease.

The dietary form of choline during lactation affects maternal immune function in rats

PURPOSE

The present study was designed to determine the effects of both choline form and availability on maternal immune function during lactation.

METHODS

Sprague-Dawley rats were randomized to one of the three diets 24-48 h before parturition and fed ad libitum until 21 days postnatal: 1 g/kg choline as free choline (C, n = 11), the current form, and amount of choline in commercial diets; 1 g/kg choline as phosphatidylcholine (PC1, n = 11); or 2.5 g/kg choline as PC (PC2.5, n = 8). Choline metabolites in offspring stomach contents were quantified. At 21 days, lymphocytes from mothers' mesenteric lymph nodes and spleens were isolated and phenotypes and ex vivo cytokine production after mitogen exposure were determined.

RESULTS

There was a higher proportion of choline and a lower proportion of lyso-PC in stomach contents (representing dam's milk) of C pups compared to PC1. In the mesenteric lymph nodes, feeding PC1 compared to C led to a higher IL-2 production after Concanavalin A (ConA) stimulation and a higher proportion of T cells (CD3+) and a lower proportion of B cells [immunoglobulin (Ig)κ, CD45RA+, and IgM+; P < 0.05]. Splenocytes from the PC1 group produced more IL-6 and TNF-α after lipopolysaccharides stimulation compared to C (P < 0.05). Splenocytes from the PC2.5 group produced more IL-2 and IL-6 after ConA stimulation compared to PC1 (P < 0.05).

CONCLUSIONS

Feeding choline as PC in the maternal diet improved the ability of immune cells to respond ex vivo to mitogens and increasing the amount of PC in the diet further improved T cell proliferation.

Phosphatidylcholine as a metabolic cue for determining B cell fate and function

In activated B cells, increased production of phosphatidylcholine (PtdCho), the most abundant cellular phospholipid, is handled primarily by the CDP-choline pathway. B cell-specific deletion of CTP:phosphocholine cytidylyltransferase α (CCTα), the rate-limiting enzyme in the CDP-choline pathway, led to augmented IgM secretion and reduced IgG production, suggesting that PtdCho synthesis is required for germinal center reactions. To specifically assess whether PtdCho influences B cell fate during germinal center responses, we examined immune responses in mice whereby PtdCho synthesis is disrupted in B cells that have undergone class switch recombination to IgG1 (referred to as either Cγ1^wt/wt, Cγ1^Cre/wt or Cγ1^Cre/Cre based on Cre copy number). Serum IgG1 was markedly reduced in naïve Cγ1^Cre/wt and Cγ1^Cre/Cre mice, while levels of IgM and other IgG subclasses were similar between Cγ1^Cre/wt and Cγ1^wt/wt control mice. Serum IgG2b titers were notably reduced and IgG3 titers were increased in Cγ1^Cre/Cre mice compared with controls. Following immunization with T cell-dependent antigen NP-KLH, control mice generated high titer IgG anti-NP while IgG anti-NP titers were markedly reduced in both immunized Cγ1^Cre/wt and Cγ1^Cre/Cre mice. Correspondingly, the frequency of NP-specific IgG antibody-secreting cells was also reduced in spleens and bone marrow of Cγ1^Cre/wt and Cγ. 1^Cre/Cre mice compared to control mice. Interestingly, though antigen-specific IgM B cells were comparable between Cγ1^Cre/wt, Cγ1^Cre/Cre and control mice, the frequency and number of IgG1 NP-specific B cells was reduced only in Cγ1^Cre/Cre mice. These data indicate that PtdCho is required for the generation of both germinal center-derived B cells and antibody-secreting cells. Further, the reduction in class-switched ASC but not B cells in Cγ1^Cre/wt mice suggests that ASC have a greater demand for PtdCho compared to germinal center B cells.

Borophosphates and silicophosphates as plausible contributors to the emergence of life

Scientific explanations for the origin of life are incomplete and may differ on some issues. Here, we argue that some prebiological steps have occurred in environments with borophosphates and/or silicophosphates in the form of hydrogels, on the basis of their chemical groups and structural properties. These could have decreased the diffusion rate of some prebiotic molecules, stabilized molecules with vicinal cis-diol groups, reduced the hydrolytic activity of water and inserted catalytic metal ions into their networks. Additionally, these hydrogels could have acted as reaction media, supplied a phosphate source for phosphorylations and produced crystals that may have permitted enantiomeric enrichment of prebiotic molecules, thus providing conditions for the emergence of protocells.