Rhodococcus equi Virulence-Associated Antigens and Specific Antibody Response in AIDS Patients Infected with R. equi

ObjectivesTo analyze the expression of the 15- to 17-kDa plasmid-encoded antigens from Rhodococcus equi isolates of 7 AIDS patients and determine the immunologic response to these proteins in the patients' sera.MethodsThe expression of the virulence proteins in R. equi isolates and the specific antibody response were investigated by immunoblotting. Plasmid DNA was analyzed by agarose gel electrophoresis.ResultsThe only patient infected with a strain carrying the virulence 85-kb plasmid and expressing the 15- to 17-kDa antigens developed a fatal pneumonia and did not produce specific antibodies to the virulence proteins. Of the 6 patients infected with R. equi strains lacking both proteins and plasmid, only 1 subject had a pulmonary disease with poor clinical outcome and exhibited a negligible humoral immune response to R. equi antigenic components, whereas the other patients who produced a remarkable antibody response developed either an asymptomatic infection (1 case) or pneumonia (4 cases) which completely cleared up.ConclusionsOur findings suggest that R. equi disease can be induced without the expression of the 15- to 17-kDa virulence-associated plasmid-encoded antigens in HIV-infected patients with very low CD4+ cell counts. Nevertheless, both the synthesis of the virulence proteins and a defective humoral immune response to R. equi may contribute to the severity of rhodococcal disease

Hidden genetic variation in plasticity provides the potential for rapid adaptation to novel environments

Rapid environmental change is forcing populations into novel environments where plasticity will no longer maintain fitness. When populations are exposed to novel environments, evolutionary theory predicts that genetic variation in fitness will increase and should be associated with genetic differences in plasticity. If true, then genetic variation in plasticity can increase adaptive potential in novel environments, and population persistence via rapid adaptation is more likely. To test whether genetic variation in fitness increases in novel environments and is associated with plasticity, we transplanted 8,149 clones of 314 genotypes of a Sicilian daisy (Senecio chrysanthemifolius) within and outside its native range, and quantified genetic variation in fitness, and plasticity in leaf traits and gene expression. Although mean fitness declined by 87% in the novel environment, genetic variance in fitness increased threefold and was correlated with plasticity in leaf traits. High fitness genotypes showed greater plasticity in gene expression, but lower plasticity in most leaf traits. Interestingly, genotypes with greater fitness in the novel environment had the lowest fitness at the native site. These results suggest that standing genetic variation in plasticity could help populations to persist and adapt to novel environments, despite remaining hidden in native environments

Effect of a probiotic administration on inflammatory profile and clinical features in patients with Alzheimer's disease

AbstractBackgroundIncreasing evidence shows that the gut microbiota (GMB) may affect the inflammatory status and influence the pathogenesis of several brain disorders, including Alzheimer's Disease. Moreover, it has been suggested that probiotics may have potential beneficial effects on the immune system via microbiome composition, influencing in turn also cognitive performances.MethodSixty‐two old subjects with normal cognitive performance and 37 AD patients were recruited and stool and blood samples were collected. Moreover, the group of AD patients received a probiotic administration for three months and stool and blood samples were collected again at the end of the treatment. Plasma levels of a panel of pro‐inflammatory cytokines were measured by using the High Sensitivity 9‐Plex Human ProcartaPlex™ Panel (IFN‐ϒ, IL‐1b, IL‐2, IL‐4, IL‐6, IL‐10, IL‐12p70, IL‐17A and TNFα, Thermo Fisher Scientific) on Luminex Bio‐Plex® 200™ system. Moreover, we also measured the plasma levels of C‐Reactive Protein (CRP) using the CRP Human Instant ELISA Kit (Thermo Fisher Scientific). Bacterial composition of fecal samples was inferred using 16s sequencing; the levels of the short chain fatty acids acetate, propionate, valerate and butyrate were measured by mass spectrometry and adhesion molecules by FACS.ResultWe found higher levels of the pro‐inflammatory cytokines IL‐6, IFN gamma, TNF‐alpha, IL‐1beta, and il12p70 and of IL‐2 and lower levels of the anti‐inflammatory cytokine IL‐10 in AD patients as compared to control subjects (all p<0.05). Moreover, we found a positive correlation between MMSE score and the levels of pro‐inflammatory cytokine IL‐6 (p=0.03, r=0.56). Interestingly, the three months treatment with the probiotic composition was able to significantly reduce the level of IL‐6 (p=0.03) and increase the levels of IL‐10 (p=0.023). Bioinformatic analyses on the 16s sequencing data as well as on the SCFAs and endothelial markers are ongoing.ConclusionInflammatory status is higher in AD patients as compared to control subjects and it correlates with cognitive performances. Interestingly probiotic composition is able to push down the inflammatory status in patients, possibly via changes in microbiome composition. Probiotics may be beneficial in delaying neurodegeneration and cognitive deficits in subjects at risk of developing Alzheimer Disease

Environmental effects on genetic variance are likely to constrain adaptation in novel environments

Lay Summary: The potential for populations to adapt rapidly to new environments will depend on the amount of genetic variation in multiple traits that make up a multidimensional phenotype. If traits are tightly correlated at the genetic level, then selection will change all traits together and adaptation will be forced into directions determined by the genetic architecture of the traits. However, genotypes can produce different phenotypes in different environments, known as plasticity. If genotypes vary in their responses to the environment, then plasticity in a novel environment could determine how much genetic variation lies in the direction of selection, and therefore the potential for rapid adaptation. We focus on two closely related sister species of Sicilian daisy (Senecio) that are native to low and high elevations on Mt. Etna. We generated and then reciprocally planted seeds of both species at four elevations on Mt. Etna, including their native habitats and two intermediate elevations. We tested how genetic variation in ecologically important leaf traits changed across elevations, and whether such changes should help or hinder rapid adaptation at the edge of species’ native ranges, and in novel environments beyond their existing ranges. We found that genetic variance in leaf traits changed less between species than across elevations. Genetic variance in the high-elevation species changed most across elevations, which occurred in ways that would be likely to prevent adaptation to low elevations and, by extension, the warmer conditions being created by climate change. Genetic variance in the low-elevation species changed least across elevations and showed more potential to aid adaptation to high-elevation habitats. Together, our results show that two sister species vary in their phenotypic and genotypic responses to the environment, which suggests that closely related species can differ greatly in their potential to persist and then adapt to novel environments

Environmental effects on genetic variance are likely to constrain adaptation in novel environments

Adaptive plasticity allows populations to cope with environmental variation but is expected to fail as conditions become unfamiliar. In novel conditions, populations may instead rely on rapid adaptation to increase fitness and avoid extinction. Adaptation should be fastest when both plasticity and selection occur in directions of the multivariate phenotype that contain abundant genetic variation. However, tests of this prediction from field experiments are rare. Here, we quantify how additive genetic variance in a multivariate phenotype changes across an elevational gradient, and test whether plasticity and selection align with genetic variation. We do so using two closely related, but ecologically distinct, sister species of Sicilian daisy (Senecio, Asteraceae) adapted to high and low elevations on Mt. Etna. Using a quantitative genetic breeding design, we generated and then reciprocally planted c. 19,000 seeds of both species, across an elevational gradient spanning each species’ native elevation, and then quantified mortality and five leaf traits of emergent seedlings. We found that genetic variance in leaf traits changed more across elevations than between species. The high-elevation species at novel lower elevations showed changes in the distribution of genetic variance among the leaf traits, which reduced the amount of genetic variance in the directions of selection and the native phenotype. By contrast, the low-elevation species mainly showed changes in the amount of genetic variance at the novel high elevation, and genetic variance was concentrated in the direction of the native phenotype. For both species, leaf trait plasticity across elevations was in a direction of the multivariate phenotype that contained a moderate amount of genetic variance. Together, these data suggest that where plasticity is adaptive, selection on genetic variance for an initially plastic response could promote adaptation. However, large environmental effects on genetic variance are likely to reduce adaptive potential in novel environments

Reduction of De Novo Lipogenesis Mediates Beneficial Effects of Isoenergetic Diets on Fatty Liver: Mechanistic Insights from the MEDEA Randomized Clinical Trial

Background: Non‐alcoholic liver steatosis (NAS) results from an imbalance between hepatic lipid storage, disposal, and partitioning. A multifactorial diet high in fiber, monounsaturated fatty acids (MUFAs), n‐6 and n‐3 polyunsaturated fatty acids (PUFAs), polyphenols, and vitamins D, E, and C reduces NAS in people with type 2 diabetes (T2D) by 40% compared to a MUFA‐rich diet. We evaluated whether dietary effects on NAS are mediated by changes in hepatic de novo lipogenesis (DNL), stearoyl‐CoA desaturase (SCD1) activity, and/or β‐ oxidation.; Methods: According to a randomized parallel group study design, 37 individuals with T2D completed an 8‐week isocaloric intervention with a MUFA diet (n = 20) or multifactorial diet (n = 17). Before and after the intervention, liver fat content was evaluated by proton magnetic resonance spectroscopy, serum triglyceride fatty acid concentrations measured by gas chromatography, plasma β‐hydroxybutyrate by enzymatic method, and DNL and SCD‐1 activity assessed by calculating the palmitic acid/linoleic acid (C16:0/C18:2 n6) and palmitoleic acid/palmitic acid (C16:1/C16:0) ratios, respectively; Results: Compared to baseline, mean ± SD DNL significantly decreased after the multifactorial diet (2.2 ± 0.8 vs.1.5 ± 0.5, p = 0.0001) but did not change after the MUFA diet (1.9 ± 1.1 vs. 1.9 ± 0.9, p = 0.949), with a significant difference between the two interventions (p = 0.004). The mean SCD‐1 activity also decreased after the multifactorial diet (0.13 ± 0.05 vs. 0.10 ± 0.03; p = 0.001), but with no significant difference between interventions (p = 0.205). Fasting plasma β‐hydroxybutyrate concentrations did not change significantly after the MUFA or multifactorial diet. Changes in the DNL index significantly and positively correlated with changes in liver fat (r = 0.426; p = 0.009). Conclusions: A diet rich in multiple beneficial dietary components (fiber, polyphenols, MUFAs, PUFAs, and other antioxidants) compared to a diet rich only in MUFAs further reduces liver fat accumulation through the inhibition of DNL. Registered under ClinicalTrials.gov no. NCT03380416

Gliadin-Mediated Proliferation and Innate Immune Activation in Celiac Disease Are Due to Alterations in Vesicular Trafficking

Background and Objectives: Damage to intestinal mucosa in celiac disease (CD) is mediated both by inflammation due to adaptive and innate immune responses, with IL-15 as a major mediator of the innate immune response, and by proliferation of crypt enterocytes as an early alteration of CD mucosa causing crypts hyperplasia. We have previously shown that gliadin peptide P31-43 induces proliferation of cell lines and celiac enterocytes by delaying degradation of the active epidermal growth factor receptor (EGFR) due to delayed maturation of endocytic vesicles. IL-15 is increased in the intestine of patients affected by CD and has pleiotropic activity that ultimately results in immunoregulatory cross-talk between cells belonging to the innate and adaptive branches of the immune response. Aims of this study were to investigate the role of P31-43 in the induction of cellular proliferation and innate immune activation. Methods/Principal Findings: Cell proliferation was evaluated by bromodeoxyuridine (BrdU) incorporation both in CaCo-2 cells and in biopsies from active CD cases and controls. We used real-time PCR to evaluate IL-15 mRNA levels and FACS as well as ELISA and Western Blot (WB) analysis to measure protein levels and distribution in CaCo-2 cells. Gliadin and P31-43 induce a proliferation of both CaCo-2 cells and CD crypt enterocytes that is dependent on both EGFR and IL-15 activity. In CaCo-2 cells, P31-43 increased IL-15 levels on the cell surface by altering intracellular trafficking. The increased IL-15 protein was bound to IL15 receptor (IL-15R) alpha, did not require new protein synthesis and functioned as a growth factor. Conclusion: In this study, we have shown that P31-43 induces both increase of the trans-presented IL-15/IL5R alpha complex on cell surfaces by altering the trafficking of the vesicular compartments as well as proliferation of crypt enterocytes with consequent remodelling of CD mucosa due to a cooperation of IL-15 and EGFR

Posaconazole and midostaurin in patients with FLT3-mutated acute myeloid leukemia: Pharmacokinetic interactions and clinical facts in a real life study

: Midostaurin is used in combination with chemotherapy to treat patients with newly diagnosed FLT3-mutated acute myeloid leukemia. Chemotherapy-induced neutropenia exposes these patients to a significant risk of invasive fungal infections (IFIs). International guidelines recommend primary antifungal prophylaxis with posaconazole (PCZ) but nested analysis of a phase III trial showed that strong PCZ inhibition of CYP3A4 diminished midostaurin metabolism and increased midostaurin plasma levels; however, midostaurin-related adverse events (AEs) were only moderately exacerbated. We conducted a prospective multicenter real-life study to evaluate (i) how often concerns around PCZ-midostaurin interactions made the hematologist prescribe antifungals other than PCZ, (ii) how remarkably PCZ increased midostaurin plasma levels, and (iii) how significantly PCZ-midostaurin interactions influenced hematologic and safety outcomes of induction therapy. Although the hematologists were blinded to pharmacokinetic findings, as many as 16 of 35 evaluable patients were prescribed antifungal prophylaxis with micafungin, weak CYP3A4 inhibitor, in place of PCZ (p &lt; 0.001 for deviation from guidelines). In the 19 patients managed as per guidelines, PCZ-midostaurin interactions were more remarkable than previously characterized, such that at the end of induction therapy midostaurin minimum plasma concentration (Cmin ) was greater than three times higher than reported; moreover, midostaurin Cmin , maximum plasma concentration, and area under the curve were more than or equal to four times higher with PCZ than micafungin. Hematologic outcomes (complete remission and duration of severe neutropenia) and safety outcomes (midostaurin-related any grade or grade ≥3 AEs) were nonetheless similar for patients exposed to PCZ or micafungin, as was the number of breakthrough IFIs. In waiting for randomized phase III trials of new prophylaxis regimens, these findings show that PCZ should remain the antifungal of choice for the midostaurin-treated patient

Adipocyte fatty-acid binding protein is overexpressed in cirrhosis and correlates with clinical outcomes

Fatty-acid-binding proteins (FABPs) are small intracellular proteins that coordinate lipid-mediated processes by targeting metabolic and immune response pathways. The aim of the study was to investigate plasma FABPs levels and their relationship with clinical outcomes in cirrhosis. Plasma levels of L-FABP1(liver and kidney), I-FABP2(intestine), and A-FABP4(adipocyte and macrophages) were measured in 274 patients with decompensated cirrhosis. Hepatic gene expression of FABPs was assessed in liver biopsies from patients with decompensated cirrhosis and in liver cell types from mice with cirrhosis. Immunohistochemistry of A-FABP4 in human liver biopsy was also performed. Plasma levels of FABPs were increased in patients with decompensated cirrhosis compared to those of healthy subjects (L-FABP1: 25 (17-39) vs 10 (9-17) ng/mL p = 0.001, I-FABP2: 1.1 (0.5-2.1) vs 0.6 (0.4-1) ng/ mL p = 0.04 and A-FABP4: 37 (20-68) vs 16 (11-33) ng/mL p = 0.002), respectively. Increased A-FABP4 levels were associated with complications of cirrhosis, acute-on-chronic liver failure and poor survival. Hepatic A-FABP4 gene expression was upregulated in decompensated cirrhosis. Macrophages were the main liver cell that over-expressed A-FABP4 in experimental cirrhosis and increased A-FABP4 was found in macrophages of human biopsies by immunohistochemistry. A-FABP4 levels are increased in decompensated cirrhosis and correlate with poor outcomes. Liver macrophages appear to be the main source of A-FABP4 in decompensated cirrhosis