Post-streptococcal antibodies are associated with metabolic syndrome in a population-based cohort

Altered Gut Microbiota in Patients With Peutz–Jeghers Syndrome

Background

Peutz–Jeghers syndrome (PJS) is a rare genetic disorder characterized by the development of pigmented spots and gastrointestinal polyps and increased susceptibility to cancers. It remains unknown whether gut microbiota dysbiosis is linked to PJS.

Aim

This study aimed to assess the structure and composition of the gut microbiota, including both bacteria and fungi, in patients with PJS and investigate the relationship between gut microbiota dysbiosis and PJS pathogenesis.

Methods

The bacterial and fungal composition of the fecal microbiota was analyzed in 23 patients with PJS (cases), 17 first-degree asymptomatic relatives (ARs), and 24 healthy controls (HCs) using 16S (MiSeq) and ITS2 (pyrosequencing) sequencing for bacteria and fungi, respectively. Differential analyses of the intestinal flora were performed from the phylum to species level.

Results

Alpha-diversity distributions of bacteria and fungi indicated that the abundance of both taxa differed between PJS cases and controls. However, while the diversity and composition of fecal bacteria in PJS cases were significantly different from those in ARs and HCs, fungal flora was more stable. High-throughput sequencing confirmed the special characteristics and biodiversity of the fecal bacterial and fungal microflora in patients with PJS. They had lower bacterial biodiversity than controls, with a higher frequency of the Proteobacteria phylum, Enterobacteriaceae family, and Escherichia-Shigella genus, and a lower frequency of the Firmicutes phylum and the Lachnospiraceae and Ruminococcaceae families. Of fungi, Candida was significantly higher in PJS cases than in controls.

Conclusion

The findings reported here confirm gut microbiota dysbiosis in patients with PJS. This is the first report on the bacterial and fungal microbiota profile of subjects with PJS, which may be meaningful to provide a structural basis for further research on intestinal microecology in PJS.

Prevalence of Anti-Nuclear Antibodies and Anti-Phospholipid Antibodies in an Egyptian Cohort with Schizophrenia: A Case-Control Study

BACKGROUND

Psychiatric disorders, including schizophrenia could herald other manifestation(s) of systemic lupus erythematosus (SLE) potentially hindering timely and optimal management. Moreover, schizophrenia is among the described 'extra-criteria' manifestations of anti-phospholipid syndrome (APS). Hence, screening schizophrenia patients for SLE and APS may pose diagnostic and therapeutic implications.

OBJECTIVES

Examine schizophrenia patients with no overt connective tissue disease(s) manifestation(s) for clinical and/or serologic evidence of SLE and/or APS.

METHODS

The study included 92 schizophrenia patients [61 (66.3%) males] and 100 age- and gender-matched healthy controls. Both groups were tested for anti-nuclear antibodies (ANAs), anti-double stranded deoxyribonucleic acid (anti-dsDNA) antibodies, complement 3 (C3) and C4, and criteria anti-phospholipid antibodies (aPL) [anticardiolipin Immunoglobulin (Ig) G and IgM, anti-beta-2-glycoprotein I IgG and IgM, and lupus anticoagulant (LAC)].

RESULTS

The patients' mean age and disease duration were 28.8 ± 8.1 and 5.7 ± 2.2 years, respectively. The prevalence of ANA positivity, height of titre, and pattern was comparable between patients and controls (p = 0.9, p = 0.8 and p = 0.1, respectively). Anti-dsDNA antibodies and hypocomplementemia were absent in both groups. A significantly higher frequency of positive LAC was observed among patients compared with controls (7.6 % vs. 1 %, p = 0.02), whereas other aPL were comparable between both groups. None of the patients or controls demonstrated clinically meaningful (medium or high) aPL titres.

CONCLUSION

In our study, schizophrenia was solely associated with LAC. Thus, in the absence of findings suggestive of SLE or APS, routine screening for both diseases is questionable.

Streptococcal Exotoxin Streptolysin O Causes Vascular Endothelial Dysfunction Through PKCβ Activation

Streptolysin O (SLO) is produced by common hemolytic streptococci that cause a wide range of diseases from pharyngitis to life-threatening necrotizing fasciitis and toxic shock syndrome. While the importance of SLO in invasive hemolytic streptococcus infection has been well demonstrated, the role of circulating SLO in non-invasive infection remains unclear. The aim of this study was to characterize the pharmacological effect of SLO on vascular functions, focusing on cellular signaling pathways. In control Wistar rats, SLO treatment (1-1000 ng/mL) impaired acetylcholine-induced endothelial-dependent relaxation in the aorta and second-order mesenteric artery in a dose-dependent manner, without any effects on sodium nitroprusside-induced endothelium-independent relaxation or agonist-induced contractions. SLO also increased phosphorylation of the endothelial NO synthase (eNOS) inhibitory site at Thr495 in the aorta. Pharmacological analysis indicated that either endothelial dysfunction or eNOS phosphorylation was mediated by protein kinase Cβ (PKCβ), but not by the p38 mitogen-activated protein kinase (MAPK) pathway. Consistent with this, SLO increased phosphorylation levels of PKC substrates in the aorta. In vivo study of control Wistar rats indicated that intravenous administration of SLO did not change basal blood pressure, but significantly counteracted the acetylcholine-induced decrease in blood pressure. Interestingly, plasma anti-SLO IgG levels were significantly higher in 10- to 15-week-old spontaneously hypertensive rats compared to age-matched control rats (P<0.05). These findings demonstrated that SLO causes vascular endothelial dysfunction, which is mediated by PKCβ-induced phosphorylation of the eNOS inhibitory site. Significance Statement This study showed for the first time, that in vitro exposure of vascular tissues to SLO impairs endothelial function, an effect that is mediated by PKCb-induced phosphorylation of the eNOS inhibitory site. Intravenous administration of SLO in control and hypertensive rats blunted the ACh-induced decrease in blood pressure, providing evidence for a possible role of SLO in dysregulation of blood pressure.

Nutrient-imbalanced conditions shift the interplay between zooplankton and gut microbiota

Background

Nutrient stoichiometry of phytoplankton frequently changes with aquatic ambient nutrient concentrations, which is mainly influenced by anthropogenic water treatment and the ecosystem dynamics. Consequently, the stoichiometry of phytoplankton can markedly alter the metabolism and growth of zooplankton. However, the effects of nutrient-imbalanced prey on the interplay between zooplankton and their gut microbiota remain unknown. Using metatranscriptome, a 16 s rRNA amplicon-based neutral community model (NCM) and experimental validation, we investigated the interactions between Daphnia magna and its gut microbiota in a nutrient-imbalanced algal diet.

Results

Our results showed that in nutrient-depleted water, the nutrient-enriched zooplankton gut stimulated the accumulation of microbial polyphosphate in fecal pellets under phosphorus limitation and the microbial assimilation of ammonia under nitrogen limitation. Compared with the nutrient replete group, both N and P limitation markedly promoted the gene expression of the gut microbiome for organic matter degradation but repressed that for anaerobic metabolisms. In the nutrient limited diet, the gut microbial community exhibited a higher fit to NCM (R² = 0.624 and 0.781, for N- and P-limitation, respectively) when compared with the Control group (R² = 0.542), suggesting increased ambient-gut exchange process favored by compensatory feeding. Further, an additional axenic grazing experiment revealed that the growth of D. magna can still benefit from gut microbiota under a nutrient-imbalanced diet.

Conclusions

Together, these results demonstrated that under a nutrient-imbalanced diet, the microbes not only benefit themselves by absorbing excess nutrients inside the zooplankton gut but also help zooplankton to survive during nutrient limitation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-020-07333-z.

Catalpol ameliorates diabetes-induced testicular injury and modulates gut microbiota

AIMS

To explore the mechanisms of diabetes mellitus (DM)-induced testicular injury caused by modulation of testicular glycolysis and gut microbiota (GM), and evaluation of the efficacy of catalpol in reversing testicular morbidity.

MAIN METHODS

A model of DM-induced testicular injury was established using a high-fat diet in KK-Ay mice. Microbial communities in the feces of mice in normal, model and catalpol (Cat) groups were analyzed by 16S gene sequencing. Correlations between the GM and lactate metabolism levels, lactate dehydrogenase activity, and indicators of testicular injury were analyzed.

KEY FINDINGS

Cat significantly reduced general indicators of diabetes in mice with DM-induced reproductive injury, mitigated damage to the testicular tissue, and increased sperm count and motility. Additionally, the levels of products of glycolysis metabolism (e.g. lactate) increased following Cat treatment compared with the Model group. Disorders in the GM were also reversed in the Cat group.

SIGNIFICANCE

Cat ameliorated DM-induced testicular injury in KK-Ay mice by increasing the energy available to germ cells through glycolysis, principally through modulation of the GM and a reduction in the quantities of associated pathogenic bacteria.

[Narcolepsy: From the discovery of a wake promoting peptide to autoimmune T cell biology and molecular mimicry with flu epitopes]

Narcolepsy-cataplexy was first described in the late 19th century in Germany and France. Prevalence was established to be 0.05 % and a canine model was discovered in the 1970s. In 1983, a Japanese study found that all patients carried HLA-DR2, suggesting autoimmunity as the cause of the disease. Studies in the canine model established that dopaminergic stimulation underlies anti-narcoleptic action of psychostimulants, while antidepressants were found to suppress cataplexy through adrenergic reuptake inhibition. No HLA association was found in canines. A linkage study initiated in 1988 revealed in hypocretin (orexin) receptor two mutations as the cause of canine narcolepsy in 1999. In 1992, studies on African Americans showed that DQ0602 was a better marker than DR2 across all ethnic groups. In 2000, hypocretin-1/orexin A levels were measured in the cerebrospinal fluid (CSF) and found to be undetectable in most patients, establishing hypocretin deficiency as the cause of narcolepsy. Decreased CSF hypocretin-1 was then found to be secondary to the loss of the 70,000 neurons producing hypocretin in the hypothalamus, suggesting immune destruction of these cells as the cause of the disease. Additional genetic studies, notably genome wide associations (GWAS), found multiple genetic predisposing factors for narcolepsy. These were almost all involved in other autoimmune diseases, although a strong and unique association with T cell receptor (TCR) alpha and beta loci were observed. Nonetheless, all attempts to demonstrate presence of autoantibodies against hypocretin cells in narcolepsy failed, and the presumed autoimmune cause remained unproven. In 2009, association with strep throat infections were found, and narcolepsy onsets were found to occur more frequently in spring and summer, suggesting upper away infections as triggers. Following reports that narcolepsy cases were triggered by vaccinations and infections against influenza A 2009 pH1N1, a new pandemic strain that erupted in 2009, molecular mimicry with influenza A virus was suggested in 2010. This hypothesis was later confirmed by peptide screening showing higher activity of CD4⁺ T cell reactivity to a specific post-translationally amidated segment of hypocretin (HCRT-_NH2) and cross-reactivity of specific TCRs with a pH1N1-specific segment of hemagglutinin that shares homology with HCRT-_NH2. Strikingly, the most frequent TCR recognizing these antigens was found to carry sequences containing TRAJ24 or TRVB4-2, segments modulated by narcolepsy-associated genetic polymorphisms. Cross-reactive CD4⁺ T cells with these cross-reactive TCRs likely subsequently recruit CD8⁺ T cells that are then involved in hypocretin cell destruction. Additional flu mimics are also likely to be discovered since narcolepsy existed prior to 2009. The work that has been conducted over the years on narcolepsy offers a unique perspective on the conduct of research on the etiopathogeny of a specific disease.

Papio spp. Colon microbiome and its link to obesity in pregnancy

INTRODUCTION

Gut microbial communities are critical players in the pathogenesis of obesity. Pregnancy is associated with increased bacterial load and changes in gut bacterial diversity. Sparse data exist regarding composition of gut microbial communities in obesity combined with pregnancy.

MATERIAL AND METHODS

Banked tissues were collected under sterile conditions during necropsy, from three non-obese (nOb) and four obese (Ob) near-term pregnant baboons. Sequences were assigned taxonomy using the Ribosomal Database Project classifier. Microbiome abundance and its difference between distinct groups were assessed by a nonparametric test.

RESULTS

Three families predominated in both the nOb and Ob colonic microbiome: Prevotellaceae (25.98% and 32.71% respectively), Ruminococcaceae (12.96% and 7.48%), and Lachnospiraceae (8.78% and 11.74%). Seven families of the colon microbiome displayed differences between Ob and nOb groups.

CONCLUSION

Changes in gut microbiome in pregnant obese animals open the venue for dietary manipulation in pregnancy.

Colonic inflammation accompanies an increase of β-catenin signaling and Lachnospiraceae/Streptococcaceae bacteria in the hind gut of high-fat diet-fed mice

Consumption of an obesigenic/high-fat diet (HFD) is associated with a high colon cancer risk and may alter the gut microbiota. To test the hypothesis that long-term high-fat (HF) feeding accelerates inflammatory process and changes gut microbiome composition, C57BL/6 mice were fed HFD (45% energy) or a low-fat (LF) diet (10% energy) for 36 weeks. At the end of the study, body weights in the HF group were 35% greater than those in the LF group. These changes were associated with dramatic increases in body fat composition, inflammatory cell infiltration, inducible nitric oxide synthase protein concentration and cell proliferation marker (Ki67) in ileum and colon. Similarly, β-catenin expression was increased in colon (but not ileum). Consistent with gut inflammation phenotype, we also found that plasma leptin, interleukin 6 and tumor necrosis factor α concentrations were also elevated in mice fed the HFD, indicative of chronic inflammation. Fecal DNA was extracted and the V1-V3 hypervariable region of the microbial 16S rRNA gene was amplified using primers suitable for 454 pyrosequencing. Compared to the LF group, the HF group had high proportions of bacteria from the family Lachnospiraceae/Streptococcaceae, which is known to be involved in the development of metabolic disorders, diabetes and colon cancer. Taken together, our data demonstrate, for the first time, that long-term HF consumption not only increases inflammatory status but also accompanies an increase of colonic β-catenin signaling and Lachnospiraceae/Streptococcaceae bacteria in the hind gut of C57BL/6 mice.

Role of antigen presentation in the production of pro-inflammatory cytokines in obese adipose tissue

Type II diabetes regroups different physiological anomalies that ultimately lead to low-grade chronic inflammation, insulin resistance and loss of pancreatic β-cells. Obesity is one of the best examples of such a condition that can develop into Metabolic Syndrome, causing serious health problems of great socio-economic consequences. The pathological outcome of obesity has a genetic basis and depends on the delicate balance between pro- and anti-inflammatory effectors of the immune system. The causal link between obesity and inflammation is well established. While innate immunity plays a key role in the development of a pro-inflammatory state in obese adipose tissues, it has now become clear that adaptive immune cells are also involved and participate in the cascade of events that lead to metabolic perturbations. The efficacy of some immunotherapeutic protocols in reducing the symptoms of obesity-driven metabolic syndrome in mice implicated all arms of the immune response. Recently, the production of pathogenic immunoglobulins and pro-inflammatory cytokines by B and T lymphocytes suggested an auto-immune basis for the establishment of a non-healthy obese state. Understanding the cellular landscape of obese adipose tissues and how immune cells sustain chronic inflammation holds the key to the development of targeted therapies. In this review, we emphasize the role of antigen-presenting cells and MHC molecules in obese adipose tissue and the general contribution of the adaptive arm of the immune system in inflammation-induced insulin resistance.

A meta-analysis of serum and cerebrospinal fluid autoantibodies in neuropsychiatric systemic lupus erythematosus

Neuropsychiatric systemic lupus erythematosus (NPSLE) is one of the most devastating presentations of SLE and comprises of psychiatric, central and peripheral neurological signs and symptoms. Previous studies suggest the possible associations between various autoantibodies (Abs) and NPSLE. The magnitudes of such association varied between studies. We performed a meta-analysis to pool data on serum and cerebrospinal fluid (CSF) levels and positivity of Abs in blood and cerebrospinal fluid in patients with NPSLE and SLE. A systematic literature search was conducted to identify studies that fulfilled inclusion criteria. A random-effects model was used to calculate overall combined odd ratio (OR) and mean levels with its corresponding 95% confidence interval to evaluate the relationship between individual Abs and NPSLE patients relative to SLE patients. Forty-one studies met the inclusion criteria and were used in this analysis. There was a significantly greater proportion of NPSLE patients who demonstrated positivity for serum anti-cardiolipin (aCL) Abs (OR=1.63, p=0.016), lupus anticoagulants (LA) Abs (OR=1.91 p=0.01), anti-phospholipid (APL) Abs (OR=2.08, p=0.001), anti-ribosomal P Abs (OR=2.29, p<0.001), anti-neuronal Abs (OR=9.50, p<0.001) as compared to SLE patients. In NPSLE patients, there was a significant increased prevalence of positive titres for CSF anti-neuronal Abs (OR=36.84, p=0.001) as compared to SLE patients. Among the 19 neuropsychiatric syndromes, the positivity of these serum autoantibodies were found specifically significantly associated with the manifestations of mood disorder, psychosis, cerebrovascular disease, seizure disorders, acute confusional state, cognitive dysfunction, headache, movement disorder, demyelinating syndrome and polyneuropathy, with ORs ranging from 1.84 to 4.73. Meta-regression identified proportion of women as significant moderator for the heterogeneity of aCL (p=0.004) and anti-neuronal Abs (p=0.0007); mean age for the heterogeneity of aCL (p=0.042) and LA (p=0.020) Abs, mean duration of illness for the heterogeneity of aCL Abs (p=0.035), and mean SLEDAI scores for the heterogeneity of anti-ribosomal P Abs (p=0.014). NPSLE patients are more likely to have elevated serum levels of aCL, LA, APL, anti-ribosomal P Abs and anti-neuronal Abs compared with SLE patients. Further research is required to evaluate the accuracy of using the above antibodies as an adjunct diagnostic tool in NPSLE.

History of narcolepsy at Stanford University

Although narcolepsy was first described in the late nineteenth century in Germany and France, much of the research on this disorder has been conducted at Stanford University, starting with Drs. William C. Dement and Christian Guilleminault in the 1970s. The prevalence of narcolepsy was established, and a canine model discovered. Following the finding in Japan that almost all patients with narcolepsy carry a specific HLA subtype, HLA-DR2, Hugh Mac Devitt, F. Carl Grumet, and Larry Steinman initiated immunological studies, but results were generally negative. Using the narcoleptic canines, Dr. Nishino and I established that stimulants increased wakefulness by stimulating dopaminergic transmission while antidepressants suppress cataplexy via adrenergic reuptake inhibition. A linkage study was initiated with Dr. Grumet in 1988, and after 10 years of work, the canine narcolepsy gene was cloned by in 1999 and identified as the hypocretin (orexin) receptor 2. In 1992, studying African Americans, we also found that DQ0602 rather than DR2 was a better marker for narcolepsy across all ethnic groups. In 2000, Dr. Nishino and I, in collaboration with Dr. Lammers in the Netherlands, found that hypocretin 1 levels in the cerebrospinal fluid (CSF) were undetectable in most cases, establishing hypocretin deficiency as the cause of narcolepsy. Pursuing this research, our and Dr. Siegel's group, examining postmortem brains, found that the decreased CSF hypocretin 1 was secondary to the loss the 70,000 neurons producing hypocretin in the hypothalamus. This finding revived the autoimmune hypothesis but attempts at demonstrating immune targeting of hypocretin cells failed until 2013. At this date, Dr. Elisabeth Mellins and I discovered that narcolepsy is characterized by the presence of autoreactive CD4(+) T cells to hypocretin fragments when presented by DQ0602. Following reports that narcolepsy cases were triggered by vaccinations and infections against influenza A 2009 pH1N1, a new pandemic strain that erupted in 2009, our groups also established that a small epitope of pH1N1 resembles hypocretin and is likely involved in molecular mimicry. Although much remains to be done, these achievements, establishing hypocretin deficiency as the cause of narcolepsy, demonstrating its autoimmune basis, and showing molecular mimicry between hypocretin and sequences derived from a pandemic strain of influenza, are likely to remain classics in human immunology.

A systematic, quantitative review of blood autoantibodies in schizophrenia

OBJECTIVE

Schizophrenia is associated with immune system dysfunction, including an increased prevalence of autoimmune disorders and autoantibodies. We performed a systematic, quantitative review of self-reacting blood antibodies in patients with schizophrenia.

METHOD

We identified articles by searching PubMed, PsychInfo, and ISI, and the reference lists of identified studies.

RESULTS

Eighty-one of 111 studies identified met the inclusion criteria. There was a significant increased prevalence of positive titers for 20 different autoantibodies in patients with schizophrenia compared to controls. The prevalence of positive anti-cardiolipin IgG and NMDA receptor titers was also significantly increased in subjects with first-episode psychosis versus controls (p<0.01). Absolute titers for anti-cardiolipin IgG and IgM, and nerve growth factor were significantly increased in patients with schizophrenia compared to controls (p<0.02 for each).

CONCLUSION

Schizophrenia is associated with an increased prevalence of multiple autoantibodies, although there is marked study heterogeneity, and correlations between autoantibodies and clinical features are inconsistent. This area merits more research evaluation, especially controlling for potential confounding factors such as clinical status, age, genetic background, psychotropic medications, BMI, and smoking.