Deciphering microbial landscapes of fish eggs to mitigate emerging diseases

Animals and plants are increasingly suffering from diseases caused by fungi and oomycetes. These emerging pathogens are now recognized as a global threat to biodiversity and food security. Among oomycetes, Saprolegnia species cause significant declines in fish and amphibian populations. Fish eggs have an immature adaptive immune system and depend on nonspecific innate defences to ward off pathogens. Here, meta-taxonomic analyses revealed that Atlantic salmon eggs are home to diverse fungal, oomycete and bacterial communities. Although virulent Saprolegnia isolates were found in all salmon egg samples, a low incidence of Saprolegniosis was strongly correlated with a high richness and abundance of specific commensal Actinobacteria, with the genus Frondihabitans (Microbacteriaceae) effectively inhibiting attachment of Saprolegniato salmon eggs. These results highlight that fundamental insights into microbial landscapes of fish eggs may provide new sustainable means to mitigate emerging diseases.     

Reprogramming factor stoichiometry influences the epigenetic state and biological properties of induced pluripotent stem cells

We compared two genetically highly defined transgenic systems to identify parameters affecting reprogramming of somatic cells to a pluripotent state. Our results demonstrate that the level and stoichiometry of reprogramming factors during the reprogramming process strongly influence the resulting pluripotency of iPS cells. High expression of Oct4 and Klf4 combined with lower expression of c-Myc and Sox2 produced iPS cells that efficiently generated "all-iPSC mice" by tetraploid (4n) complementation, maintained normal imprinting at the Dlk1-Dio3 locus, and did not create mice with tumors. Loss of imprinting (LOI) at the Dlk1-Dio3 locus did not strictly correlate with reduced pluripotency though the efficiency of generating "all-iPSC mice" was diminished. Our data indicate that stoichiometry of reprogramming factors can influence epigenetic and biological properties of iPS cells. This concept complicates efforts to define a "generic" epigenetic state of iPSCs and ESCs and should be considered when comparing different iPS and ES cell lines.     

Bone marrow p16INK4a-deficiency does not modulate obesity, glucose homeostasis or atherosclerosis development

Objective

A genomic region near the CDKN2A locus, encoding p16^INK4a, has been associated to type 2 diabetes and atherosclerotic vascular disease, conditions in which inflammation plays an important role. Recently, we found that deficiency of p16^INK4a results in decreased inflammatory signaling in murine macrophages and that p16^INK4a influences the phenotype of human adipose tissue macrophages. Therefore, we investigated the influence of immune cell p16^INK4a on glucose tolerance and atherosclerosis in mice.

Methods and Results

Bone marrow p16^INK4a-deficiency in C57Bl6 mice did not influence high fat diet-induced obesity nor plasma glucose and lipid levels. Glucose tolerance tests showed no alterations in high fat diet-induced glucose intolerance. While bone marrow p16^INK4a-deficiency did not affect the gene expression profile of adipose tissue, hepatic expression of the alternative markers Chi3l3, Mgl2 and IL10 was increased and the induction of pro-inflammatory Nos2 was restrained on the high fat diet. Bone marrow p16^INK4a-deficiency in low density lipoprotein receptor-deficient mice did not affect western diet-induced atherosclerotic plaque size or morphology. In line, plasma lipid levels remained unaffected and p16^INK4a-deficient macrophages displayed equal cholesterol uptake and efflux compared to wild type macrophages.

Conclusion

Bone marrow p16^INK4a-deficiency does not affect plasma lipids, obesity, glucose tolerance or atherosclerosis in mice.     

Hematopoietic miR155 deficiency enhances atherosclerosis and decreases plaque stability in hyperlipidemic mice

microRNA-155 (miR155) is a central regulator of immune responses that is induced by inflammatory mediators. Although miR155 is considered to be a pro-inflammatory microRNA, in vitro reports show anti-inflammatory effects in lipid-loaded cells. In this study we examined the role of miR155 in atherosclerosis in vivo using bone marrow transplantation from miR155 deficient or wildtype mice to hyperlipidemic mice. Hematopoietic deficiency of miR155 enhanced atherosclerotic plaque development and decreased plaque stability, as evidenced by increased myeloid inflammatory cell recruitment to the plaque. The increased inflammatory state was mirrored by a decrease in circulating CD4(+)CD25(+)FoxP3(+) regulatory T cells, and an increase in granulocytes (CD11b(+)Ly6G(+)) in blood of miR155(-/-) transplanted mice. Moreover, we show for the first time a crucial role of miR155 in monocyte subset differentiation, since hematopoietic deficiency of miR155 increases the 'inflammatory' monocyte subset (CD11b(+)Ly6G(-)Ly6C(hi)) and reduces 'resident' monocytes (CD11b(+)Ly6G(-)Ly6C(low)) in the circulation. Furthermore, cytokine production by resident peritoneal macrophages of miR155(-/-) transplanted hyperlipidemic mice was skewed towards a more pro-inflammatory state since anti-inflammatory IL-10 production was reduced. In conclusion, in this hyperlipidemic mouse model miR155 acts as an anti-inflammatory, atheroprotective microRNA. Additionally, besides a known role in lymphoid cell development, we show a crucial role of miR155 in myeloid lineage differentiation.     

MEG Network Differences between Low- and High-Grade Glioma Related to Epilepsy and Cognition

Objective

To reveal possible differences in whole brain topology of epileptic glioma patients, being low-grade glioma (LGG) and high-grade glioma (HGG) patients. We studied functional networks in these patients and compared them to those in epilepsy patients with non-glial lesions (NGL) and healthy controls. Finally, we related network characteristics to seizure frequency and cognitive performance within patient groups.

Methods

We constructed functional networks from pre-surgical resting-state magnetoencephalography (MEG) recordings of 13 LGG patients, 12 HGG patients, 10 NGL patients, and 36 healthy controls. Normalized clustering coefficient and average shortest path length as well as modular structure and network synchronizability were computed for each group. Cognitive performance was assessed in a subset of 11 LGG and 10 HGG patients.

Results

LGG patients showed decreased network synchronizability and decreased global integration compared to healthy controls in the theta frequency range (4–8 Hz), similar to NGL patients. HGG patients’ networks did not significantly differ from those in controls. Network characteristics correlated with clinical presentation regarding seizure frequency in LGG patients, and with poorer cognitive performance in both LGG and HGG glioma patients.

Conclusion

Lesion histology partly determines differences in functional networks in glioma patients suffering from epilepsy. We suggest that differences between LGG and HGG patients’ networks are explained by differences in plasticity, guided by the particular lesional growth pattern. Interestingly, decreased synchronizability and decreased global integration in the theta band seem to make LGG and NGL patients more prone to the occurrence of seizures and cognitive decline.     

Cognitive behavioural therapy versus multidisciplinary rehabilitation treatment for patients with chronic fatigue syndrome: study protocol for a randomized controlled trial (FatiGo)

ABSTRACT: BACKGROUND: Patients with chronic fatigue syndrome (CFS) experience extreme fatigue which often leads to substantial limitations of occupational, educational, social and personal activities. Currently, there is no consensus regarding the treatment of patients with CFS. Patients try many different therapies to overcome their fatigue. Although there is no consensus, Cognitive Behavioural Therapy (CBT) is seen as one of the most effective treatments. Little is known about multidisciplinary rehabilitation treatment (MRT), a combination of CBT with principles of mindfulness, gradual increase of activities, body awareness therapy and pacing. The difference in effectiveness and cost-effectiveness between MRT and CBT for treatment of patients with CFS is as yet unknown. The FatiGo (Fatigue-Go) trial aims to compare the effects of both treatment approaches in outpatient rehabilitation on fatigue severity and quality of life in patients with CFS. METHODS: One hundred and twenty patients, who meet the criteria of CFS, fulfil the inclusion criteria and signed the informed consent form, will be recruited into a randomised controlled trial. Both treatments, CBT and MRT, take 6 months to complete. Outcome will be assessed at 6 and 12 months after start of treatment. Two weeks after start of treatment, expectancy and credibility will be measured and patients are asked to write down their personal goals and score their current performance on these goals on a Visual Analogue Scale (VAS). At 6 and 14 weeks after start of treatment, primary outcome and three potential mediators; self-efficacy, causal attributions, present-centred attention-awareness, will be measured. Primary outcomes are fatigue severity and quality of life. Secondary outcomes are physical activity, psychological symptoms, self-efficacy, causal attributions, impact of disease on emotional and physical functioning, present-centred attention-awareness, life satisfaction, patient personal goals, self rated improvement and economic costs. The primary analysis will be based on intention to treat and longitudinal analysis of covariance will be used to compare treatments. Trial registration: Current Controlled Trials ISRCTN77567702. CONCLUSIONS: The results of the trial will provide information on the effects of CBT and MRT at 6 and 12 months follow up, mediators of the outcome, cost-effectiveness, cost-utility, and the influence of treatment expectancy and credibility on the effectiveness of both treatments in patients with CFS.     

Altered neurochemical profile in the McGill‐R‐Thy1‐APP rat model of Alzheimer's disease: a longitudinal in vivo 1H MRS study

We investigated metabolite levels during the progression of pathology in McGill‐R‐Thy1‐APP rats, a transgenic animal model of Alzheimer's disease, and in healthy age‐matched controls. Rats were subjected to in vivo ¹H magnetic resonance spectroscopy (MRS) of the dorsal hippocampus at age 3, 9 and 12 months and of frontal cortex at 9 and 12 months. At 3 months, a stage in which only Aβ oligomers are present, lower glutamate, myo‐inositol and total choline content were apparent in McGill‐R‐Thy1‐APP rats. At age 9 months, lower levels of glutamate, GABA, N‐acetylaspartate and total choline and elevated myo‐inositol and taurine were found in dorsal hippocampus, whereas lower levels of glutamate, GABA, glutamine and N‐acetylaspartate were found in frontal cortex. At age 12 months, only the taurine level was significantly different in dorsal hippocampus, whereas taurine, myo‐inositol, N‐acetylaspartate and total creatine levels were significantly higher in frontal cortex. McGill‐R‐Thy1‐APP rats did not show the same changes in metabolite levels with age as displayed in the controls, and overall, prominent and complex metabolite differences were evident in this transgenic rat model of Alzheimer's disease. The findings also demonstrate that in vivo ¹H MRS is a powerful tool to investigate disease‐related metabolite changes in the brain.     

Expression of IL-20 in synovium and lesional skin of patients with psoriatic arthritis: differential response to alefacept treatment

Introduction

Psoriatic arthritis (PsA) is an inflammatory joint disease associated with psoriasis. Alefacept (a lymphocyte function-associated antigen (LFA)-3 Ig fusion protein that binds to CD2 and functions as an antagonist to T-cell activation) has been shown to result in improvement in psoriasis but has limited effectiveness in PsA. Interleukin-20 (IL-20) is a key proinflammatory cytokine involved in the pathogenesis of psoriasis. The effects of alefacept treatment on IL-20 expression in the synovium of patients with psoriasis and PsA are currently unknown.

Methods

Eleven patients with active PsA and chronic plaque psoriasis were treated with alefacept (7.5 mg per week for 12 weeks) in an open-label study. Skin biopsies were taken before and after 1 and 6 weeks, whereas synovial biopsies were obtained before and 4 and 12 weeks after treatment. Synovial biopsies from patients with rheumatoid arthritis (RA) (n = 10) were used as disease controls. Immunohistochemical analysis was performed to detect IL-20 expression, and stained synovial tissue sections were evaluated with digital image analysis. Double staining was performed with IL-20 and CD68 (macrophages), and conversely with CD55 (fibroblast-like synoviocytes, FLSs) to determine the phenotype of IL-20-positive cells in PsA synovium. IL-20 expression in skin sections (n = 6) was analyzed semiquantitatively.

Results

IL-20 was abundantly expressed in both PsA and RA synovial tissues. In inflamed PsA synovium, CD68⁺ macrophages and CD55⁺ FLSs coexpressed IL-20, and its expression correlated with the numbers of FLSs. IL-20 expression in lesional skin of PsA patients decreased significantly (P = 0.04) 6 weeks after treatment and correlated positively with the Psoriasis Area and Severity Index (PASI). IL-20 expression in PsA synovium was not affected by alefacept.

Conclusions

Conceivably, the relatively limited effectiveness of alefacept in PsA patients (compared with anti-tumor necrosis factor (TNF) therapy) might be explained in part by persistent FLS-derived IL-20 expression.     

Gross deletions involving IGHM, BTK, or Artemis: a model for genomic lesions mediated by transposable elements

Most genetic disruptions underlying human disease are microlesions, whereas gross lesions are rare with gross deletions being most frequently found (6%). Similar observations have been made in primary immunodeficiency genes, such as BTK, but for unknown reasons the IGHM and DCLRE1C (Artemis) gene defects frequently represent gross deletions ( approximately 60%). We characterized the gross deletion breakpoints in IGHM-, BTK-, and Artemis-deficient patients. The IGHM deletion breakpoints did not show involvement of recombination signal sequences or immunoglobulin switch regions. Instead, five IGHM, eight BTK, and five unique Artemis breakpoints were located in or near sequences derived from transposable elements (TE). The breakpoints of four out of five disrupted Artemis alleles were located in highly homologous regions, similar to Ig subclass deficiencies and Vh deletion polymorphisms. Nevertheless, these observations suggest a role for TEs in mediating gross deletions. The identified gross deletion breakpoints were mostly located in TE subclasses that were specifically overrepresented in the involved gene as compared to the average in the human genome. This concerned both long (LINE1) and short (Alu, MIR) interspersed elements, as well as LTR retrotransposons (ERV). Furthermore, a high total TE content (>40%) was associated with an increased frequency of gross deletions. Both findings were further investigated and confirmed in a total set of 20 genes disrupted in human disease. Thus, to our knowledge for the first time, we provide evidence that a high TE content, irrespective of the type of element, results in the increased incidence of gross deletions as gene disruption underlying human disease.