Strain variation in glycosaminoglycan recognition influences cell-type-specific binding by lyme disease spirochetes

Lyme disease, a chronic multisystemic disorder that can affect the skin, heart, joints, and nervous system is caused by Borrelia burgdorferi sensu lato. Lyme disease spirochetes were previously shown to bind glycosaminoglycans (GAGs). In the current study, the GAG-binding properties of eight Lyme disease strains were determined. Binding by two high-passage HB19 derivatives to Vero cells could not be inhibited by enzymatic removal of GAGs or by the addition of exogenous GAG. The other six strains, which included a different high-passage HB19 derivative (HB19 clone 1), were shown to recognize both heparan sulfate and dermatan sulfate in cell-binding assays, but the relative efficiency of binding to these two GAGs varied among the strains. Strains N40, CA20-2A, and PBi bound predominantly to heparan sulfate, PBo bound both heparan sulfate and dermatan sulfate roughly equally, and VS461 and HB19 clone 1 recognized primarily dermatan sulfate. Cell binding by strain HB19 clone 1 was inhibited better by exogenous dermatan sulfate than by heparin, whereas heparin was the better inhibitor of binding by strain N40. The GAG-binding preference of a Lyme disease strain was reflected in its cell-type-specific binding. Strains that recognized predominantly heparan sulfate bound efficiently to both C6 glioma cells and EA-Hy926 cells, whereas strains that recognized predominantly dermatan sulfate bound well only to the glial cells. The effect of lyase treatment of these cells on bacterial binding was consistent with the model that cell-type-specific binding was a reflection of the GAG-binding preference. We conclude that the GAG-binding preference varies with the strain of Lyme disease spirochete and that this variation influences cell-type-specific binding in vitro.     

Entomophthoromycosis in South Bengal (Eastern India): a 9 years study

Subcutaneous mycoses caused by the family Entomophthoraceae is very rare type of disease and is being reported sporadically from various Tropical countries including India. Here we report 8 cases of rhinoentomophthoromycosis caused by Conidiobolous coronatus and 7 cases of chronic subcutaneous phycomycosis caused by Basidiobolus ranarum. Cases were detected during a span of 9 years between 1991 to 1999, from 9 districts in and around Kolkata (Eastern India). Former type of lesions were detected among 20 to 65 age group of healthy individuals, predominantly males (7:1). In the latter type, male-female ratio was 2:5, and except for one all cases belonged to below 20 years age group of healthy individuals. Several cases were detected only after examination of repeat biopsy samples. With high degree of clinical suspicion, right approach is needed for laboratory confirmation of diagnosis.     

Nematode ascarosides attenuate mammalian type 2 inflammatory responses

Mounting evidence suggests that nematode infection can protect against disorders of immune dysregulation. Administration of live parasites or their excretory/secretory (ES) products has shown therapeutic effects across a wide range of animal models for immune disorders, including asthma. Human clinical trials of live parasite ingestion for the treatment of immune disorders have produced promising results, yet concerns persist regarding the ingestion of pathogenic organisms and the immunogenicity of protein components. Despite extensive efforts to define the active components of ES products, no small molecules with immune regulatory activity have been identified from nematodes. Here we show that an evolutionarily conserved family of nematode pheromones called ascarosides strongly modulates the pulmonary immune response and reduces asthma severity in mice. Screening the inhibitory effects of ascarosides produced by animal-parasitic nematodes on the development of asthma in an ovalbumin (OVA) murine model, we found that administration of nanogram quantities of ascr#7 prevented the development of lung eosinophilia, goblet cell metaplasia, and airway hyperreactivity. Ascr#7 suppressed the production of IL-33 from lung epithelial cells and reduced the number of memory-type pathogenic Th2 cells and ILC2s in the lung, both key drivers of the pathology of asthma. Our findings suggest that the mammalian immune system recognizes ascarosides as an evolutionarily conserved molecular signature of parasitic nematodes. The identification of a nematode-produced small molecule underlying the well-documented immunomodulatory effects of ES products may enable the development of treatment strategies for allergic diseases.

Parasitic nematodes are associated with almost all groups of vertebrates, and nearly one-third of the human population is infected with these helminths (1). Their omnipresence is in part due to their ability to modulate host immune responses to prevent immune attack and expulsion (2). The elimination of nematode infections has been proposed as a possible cause of the increased incidence of autoimmune disorders and allergic diseases in developed countries (3), based on epidemiological data showing a correlation between the decline in helminth infection and the rise in allergic and autoimmune diseases, including asthma, multiple sclerosis (MS), type 1 diabetes, and inflammatory bowel diseases (IBDs) (4).The administration of live nematodes or their excretory/secretory (ES) products has shown therapeutic effects across a wide range of animal models for these immune disorders (5–8). The US Food and Drug Administration recently approved live helminth administration as an investigational drug for the treatment of immune disorders, and relevant human clinical trials are ongoing (9). Despite mounting evidence that helminths have significant therapeutic potential, we do not yet have a comprehensive understanding of the molecules that underlie their immunomodulatory effects; and, in particular, the possible relevance of low-molecular-weight components of ES products has remained largely unexplored.A wide range of nematodes, including many parasitic species, produce ascarosides, a family of small-molecule signals based on glycosides of the dideoxysugar ascarylose (10). Ascarosides have not yet been identified in any other animal phylum, suggesting that they may be a nematode-specific class of small molecules (SI Appendix, Fig. S1A). The first ascaroside-based signaling molecules were identified in the free-living model nematode Caenorhabditis elegans (11, 12). Ascarosides regulate almost every aspect of C. elegans life history, including diapause (dauer) induction, aging, mate finding, and aggregation (11, 12). Subsequently, ascarosides have been shown to be detected by organisms other than nematodes, such as nematophagous fungi that set traps to capture and digest nematodes (13). The perception of ascarosides is sufficient to trigger trap formation in these fungi, demonstrating their longstanding evolutionary association with nematodes. Furthermore, ascarosides produced by plant-pathogenic nematodes have been shown to trigger innate immune responses in monocot and dicot plants (14). Cumulatively, these findings suggest that ascarosides represent a nematode-specific molecular signature that is recognized and interpreted by nematode predators and hosts across multiple kingdoms.In this study, we collected ES products from the gut-resident, rodent-parasitic nematode Nippostrongylus brasiliensis. Previous studies showed that the administration of N. brasiliensis ES (NES) products fully inhibits the development of airway hyperresponsiveness (AHR) in the ovalbumin (OVA) murine model of asthma (15). Specifically, NES products substantially prevented lung eosinophilia, mucus production, and resistance to airflow. Notably, it was found that heat-treated or proteinase K–treated NES mimicked the full effect of untreated NES products in reducing lung eosinophilia and OVA-specific IgG in serum. Therefore, we hypothesized that the therapeutic effect of NES products may be due to the presence of specific small molecules that may in part be bound to secreted proteins, explaining the activity of heat- or proteinase K–treated NES. To test this hypothesis, we isolated the small molecule fraction of heat-treated NES (small molecule ES [smES]) products via filtration through a 3-kDa filter and found that smES products strongly suppresses OVA-induced allergic immune responses. Parallel chemical analyses of several other mammalian parasitic nematodes confirmed the presence of specific ascarosides in smES products of all tested species. Next, we tested synthetic samples of ascarosides and found that ascr#7, a compound produced by N. brasiliensis and other parasitic species, markedly inhibited the development of allergic airway inflammation, comparable to the full effect of smES products. Mechanistically, we found that ascr#7 administration attenuated IL-33 production from lung epithelial cells and suppressed the proliferation of memory-type IL-5–producing pathogenic T helper 2 (Th2) cells and type 2 innate lymphoid cells (ILC2s) in the lung, both key drivers for the pathology of asthma. We thus demonstrate that ascarosides have an immunomodulatory role that attenuates OVA-induced allergic inflammation in a murine model.     

Association of bone marrow fibrosis with inferior survival outcomes in chronic myelomonocytic leukemia

The impact of bone marrow fibrosis grade on the prognosis of patients with chronic myelomonocytic leukemia (CMML) remains controversial. Therefore, we examined the records of 82 patients diagnosed with CMML at our institution and summarized baseline characteristics and molecular profiles by subgroups of absent or mild (grades 0/1) and moderate (grade 2) fibrosis. Cox proportional hazards models were constructed to assess the prognostic significance of fibrosis grade. Grade 2 fibrosis was identified in 63 patients (76.8%), grade 1 in 16 patients (19.5%), and grade 0 in 3 patients (3.7%). Grade 2 fibrosis was associated with reduced hemoglobin levels (median 9.75 vs 11.0 g/dL in grade 0/1; p?=?0.04) and increased percentages of ringed sideroblasts (7.5 vs 0%; p?=?0.008). In multivariable analysis, grade 2 fibrosis was an independent predictor of poor overall survival (OS; 95% CI 1.32–6.35; HR 2.90; p?=?0.008), but not event-free survival (EFS; 95% CI 0.62–2.67; HR 1.28; p?=?0.50). Absolute neutrophil count (ANC) was found to impact OS (95% CI 1.01–1.09; HR 1.05; p?=?0.009), while both ANC (95% CI 1.00–1.07; HR 1.04; p?=?0.04) and peripheral blood blast percentage (95% CI 1.02–1.32; HR 1.16; p?=?0.02) impacted EFS. These results implicate fibrosis grade is an important indicator of prognosis, with high-grade fibrosis predicting inferior survival. Given the prevalence of marrow fibrosis in CMML, fibrosis grading should be incorporated into prognostic assessment and therapeutic decision-making.     

Lysozyme: a mediator of myocardial depression and adrenergic dysfunction in septic shock in dogs

The objective of the present study was to identify the nature of a filterable cardiodepressant substance (FCS) that contributes to myocardial dysfunction in a canine model of Escherichia coli septic shock. In a previous study, it was found that FCS increased in plasma after 4 h of bacteremia (Am J Physiol 1993;264:H1402) in which FCS was identified by a bioassay that included a right ventricular trabecular (RVT) preparation. In that study, FCS was only partially identified by pore filtration techniques and was found to be a protein of molecular weight between 10 and 30 K. In the present study, FCS was further purified by size exclusion high-pressure liquid chromatography, until a single band was identified on one-dimensional gel electrophoresis. This band was then subjected to tandem mass spectrometry and protein-sequencing techniques and both techniques identified FCS as lysozyme c (Lzm-S), consistent with that originating from the canine spleen. Confirmatory tests showed that purified Lzm-S produced myocardial depression in the RVT preparation at concentrations achieved during sepsis in the in vivo preparation. In addition, Lzm-S inhibited the adrenergic response induced by field stimulation and the beta- agonist isoproterenol in in vitro preparations, these results suggesting that Lzm-S may inhibit the sympathetic response in sepsis. The present findings indicate that Lzm-S originating from disintegrating leukocytes from organs such as the spleen contributes to myocardial dysfunction in this model. The mechanism may relate to its binding or hydrolysis of a cardiac membrane glycoprotein thereby interfering with myocardial excitation-contraction coupling in sepsis.     

Are some patient-perceived migraine triggers simply early manifestations of the attack?

Journal of Neurology - To study the agreement between self-reported trigger factors and early premonitory symptoms amongst a group of migraineurs in both spontaneous and pharmacologically provoked...     

The hunt for a yet unknown: Common molecular signature in some genetically monomorphic enterobacteria

Mark Achtman introduced the term “genetically monomorphic bacteria” (GM bacteria) for some human and plant pathogens. They displayed a great uniformity in terms of their “genetic” properties. This “uniformity” poses a challenge to microbiologists. To address these problems, we used CodonW and IslandViewer 3 as analytical tools and took Escherichia coli, Salmonella, and Shigella strains as a model organisms. We hypothesized that GM bacterium contains a common molecular signature among them. We have found a significant correlation regarding the number of protein-coding genes, predicted highly expressed genes, and the highest length of gene in this regard. On the other hand, the correspondence analysis of pathogenicity-related genes identified by IslandViewer 3 displayed a somewhat unique pattern in GM bacteria. The probable pathogenic genes are clustered into two separate groups, which is a hallmark of some pattern. Similar genes of non-monomorphic pathogenic strain clustered almost similarly, but the clusters are joined together, they are not completely separated. These features, in our considered view, may be considered as codon usages signatures of these bacteria, and E. coli in particular.