ASK1 signaling regulates phase-specific glial interactions during neuroinflammation

Neuroinflammation is well known to be associated with neurodegenerative diseases. Apoptosis signal-regulating kinase 1 (ASK1) is a mitogen-activated protein kinase kinase kinase that has been implicated in neuroinflammation, but its precise cellular and molecular mechanisms remain unknown. In this study, we generated conditional knockout (CKO) mice that lack ASK1 in T cells, dendritic cells, microglia/macrophages, microglia, or astrocytes, to assess the roles of ASK1 during experimental autoimmune encephalomyelitis (EAE). We found that neuroinflammation was reduced in both the early and later stages of EAE in microglia/macrophage-specific ASK1 knockout mice, whereas only the later-stage neuroinflammation was ameliorated in astrocyte-specific ASK1 knockout mice. ASK1 deficiency in T cells and dendritic cells had no significant effects on EAE severity. Further, we found that ASK1 in microglia/macrophages induces a proinflammatory environment, which subsequently activates astrocytes to exacerbate neuroinflammation. Microglia-specific ASK1 deletion was achieved using a CX3CR1^CreER system, and we found that ASK1 signaling in microglia played a major role in generating and maintaining disease. Activated astrocytes produce key inflammatory mediators, including CCL2, that further activated and recruited microglia/macrophages, in an astrocytic ASK1-dependent manner. Astrocyte-specific analysis revealed CCL2 expression was higher in the later stage compared with the early stage, suggesting a greater proinflammatory role of astrocytes in the later stage. Our findings demonstrate cell-type–specific roles of ASK1 and suggest phase-specific ASK1-dependent glial cell interactions in EAE pathophysiology. We propose glial ASK1 as a promising therapeutic target for reducing neuroinflammation.

Apoptosis signal-regulating kinase 1 (ASK1) is a mitogen-activated protein kinase (MAPK) kinase kinase that stimulates the c-Jun N-terminal kinase (JNK) and p38 MAPK pathways, and it mediates diverse biological signals leading to cell death, differentiation, and senescence (1, 2). Deletion of ASK1 in mice suppresses neuronal cell death from injury (3, 4), and recent studies indicate that ASK1 is involved in various neurodegenerative diseases, including amyotrophic lateral sclerosis, Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis (MS) (5–8). MS is an inflammatory disease of the central nervous system (CNS) characterized by localized areas of demyelination. Experimental autoimmune encephalomyelitis (EAE) is a classic model widely used to explore pathogenic mechanisms of MS, generated by administering a myelin basic protein peptide that induces an autoimmune response directed to myelin (9). During MS/EAE, activated microglia/macrophages are the first cells to respond to inflammatory insults within the CNS. Microglia/macrophages may be polarized into proinflammatory or antiinflammatory states, with each state having a distinct molecular phenotype and effector function, and targeting microglia/macrophages may have therapeutic benefits in MS/EAE treatment (10–12). Astrocytes, another subset of glia, are the most abundant cell population within the CNS. Astrocytes are involved in the regulation of synaptic function, plasticity, and maintaining brain homeostasis, and they are thought to contribute to the pathogenesis of MS/EAE by producing proinflammatory cytokine/chemokines such as CCL2 (13–16). In recent years, astrocytes have also been shown to polarize into different subtypes: A1 astrocytes are neurotoxic, and blocking the conversion of astrocytes into the A1 phenotype is neuroprotective (17, 18); although, nowadays, the activation state is described to be more diverse than the simple A1/A2 nomenclature (19, 20). Studies of intrinsic and external factors involved in astrocyte activation or polarization may provide information regarding how astrocytic function changes during disease, which may lead to the development of novel therapies.We previously reported that ASK1 deficiency ameliorated the severity of EAE, using conventional ASK1 knockout (ASK1 KO) mice (21). In this study, we selectively deleted ASK1 from five types of cells: T cells, dendritic cells, microglia/macrophages, microglia, and astrocytes, to dissect out the roles of ASK1 in different cell types during neuroinflammation. Our study revealed pathogenic roles of ASK1 signaling in innate immune cells and how they interact with each other in the progression of MS/EAE.     

Association of hla-b39 with hla-b27-negative ankylosing spondylitis and pauciarticular juvenile rheumatoid arthritis in japanese patients

Objective. To investigate the characteristics of HLA-B27 that render susceptibility to seronegative spondylarthropathies. Methods. Serologic HLA class I typing of Japanese patients with ankylosing spondylitis (AS), juvenile rheumatoid arthritis (JRA), and healthy controls, was performed. HLA-B39 subtypes were determined by polymerase chain reaction-sequence-specific oligohy-bridization. Results. HLA-B27 was present in 40 of 48 patients with AS (83%), and in only 1 of 210 healthy controls (0.5%). Three of 8 patients (37.5%) who were negative for HLA-B27 were positive for HLA-B39, which was significantly higher compared with the HLA-B27-negative controls (6.2% P = 0.01). Significant association with HLA-B39 was also noted in the JRA patients (16.7%; P < 0.01), especially in those patients with pauciarticular-onset disease (33.3%; P < 0.01). Ten of 13 HLA-B39-positive patients had subtype B^*3901 and 3 had B^*3902. Conclusion. Because HLA-B27 and HLA-B39 share Glu at position 45 and Cys at position 67, both of which constitute components of the peptide-anchoring B pocket, and because they possess similar peptide-ligand motifs, our results may support either the role of the peptides presented by class I antigens or the importance of Cys at position 67, in the development of spondylarthropathies and pauciarticular-onset JRA.     

Loss of Amino Acids Into Dialysate During Hemodialysis Using Hydrophilic and Nonhydrophilic Polyester–Polymer Alloy and Polyacrylonitrile Membrane Dialyzers

During hemodialysis, amino acid loss through the dialysate remained a significant problem and was not clear in some dialyzers; therefore, we investigated amino acid loss with hydrophilic and nonhydrophilic polyester–polymer alloy membranes and polyacrylonitrile membranes. Nine maintenance hemodialysis patients were studied to assess amino acid loss during hemodialysis with the three membranes. Total amino acid losses were 85.7 ± 27.2 mg/L, 83.3 ± 16.1 mg/L, and 72.1 ± 22.5 mg/L with the hydrophilic, nonhydrophilic polyester–polymer alloy, and polyacrylonitrile membranes, respectively. Amino acid losses were greater with the hydrophilic membrane compared with the polyacrylonitrile membrane for ornithine (2.0 ± 0.6 vs. 1.4 ± 0.4 mg/L, P = 0.025), phenylalanine (2.4 ± 0.9 vs. 1.8 ± 0.8 mg/L, P = 0.012), and tryptophan (0.6 ± 0.2 vs. 0.4 ± 0.2 mg/L, P = 0.023). Amino acid losses were greater with the nonhydrophilic membrane than with the polyacrylonitrile membrane for ornithine (2.0 ± 0.4 vs. 1.4 ± 0.4 mg/L, P = 0.017), phenylalanine (2.3 ± 0.5 vs. 1.8 ± 0.8 mg/L, P = 0.018), tryptophan (0.7 ± 0.2 vs. 0.4 ± 0.2 mg/L, P = 0.003), and cystine (3.2 ± 0.7 vs. 2.0 ± 0.7 mg/L, P = 0.005). In conclusion, greater losses of ornithine, phenylalanine, tryptophan, and cystine were observed with polyester–polymer alloy than with polyacrylonitrile membranes during hemodialysis. Constant attention should be paid to the amino acid loss profile to improve nutritional control in hemodialysis patients.     

Mesenteric lymph nodes contribute to proinflammatory Th17‐cell generation during inflammation of the small intestine in mice

T cells of the small intestine, including Th17 cells, are critically involved in host protection from microbial infection, and also contribute to the pathogenesis of small bowel inflammatory disorders. Accumulating evidence suggests that mesenteric lymph nodes (MLNs) play important roles in gut‐tropic T‐cell generation, although it is still unclear if MLNs are involved in the pathogenesis of small intestine inflammation. To address this issue, we analyzed the roles of both MLNs and Peyer's patches (PPs) by evaluating MLN‐ or PP‐deficient mice in an experimental model of small intestine inflammation, induced by CD3‐specific mAb injection. Interestingly, MLNs, but not PPs, were essential for the pathogenesis of intestinal inflammation, in particular the accumulation and infiltration of CD4⁺ T‐cell populations, including Th17 cells, from the blood. In addition, CD4⁺ T‐cell accumulation was dependent on the function of the α₄β₇ integrin. Furthermore, MLN removal led to a significantly reduced number of peripheral α₄β₇⁺ CD4⁺ effector memory T cells under normal conditions, suggesting that MLNs may play a role in maintaining the number of gut‐tropic CD4⁺ effector memory T cells circulating in the blood. Taken together, the present study highlights the important role of MLNs in contributing to the pathogenesis of small intestine inflammation.     

Renal epithelioid angiomyolipoma with malignant features: Histological evaluation and novel immunohistochemical findings

Renal epithelioid angiomyolipoma (EAML) is a potentially malignant tumor type whose characteristics and biomarkers predictive of malignant behavior have not been elucidated. Here, we report three cases of renal EAML with malignant features but without histories of tuberous sclerosis complex. Case 1 involved a 29‐year‐old man with a 12‐cm solid mass in the right kidney who underwent radical right nephrectomy. Case 2 involved a 22‐year‐old woman with a retroperitoneal mass who underwent radical right nephrectomy and retroperitoneal tumorectomy. Local recurrence was detected 7 years post‐surgery. Case 3 involved a 23‐year‐old man with a 14‐cm solid mass in the left kidney who underwent radical left nephrectomy. Microscopically, the tumors in all cases demonstrated proliferation of epithelioid cells with atypia, mitotic activity, necrosis, hemorrhage, and vascular invasion. Epithelioid cells in all cases were immunohistochemically positive for melanocytic and myoid markers and weakly positive for E‐cadherin and β‐catenin. Immunohistochemistry revealed activation of the mammalian target of rapamycin pathway. Here, we report the morphological and immunohistochemical features of clinically or histologically malignant renal EAML.     

Avidity of technetium 99m glucarate for the necrotic myocardium: In vivo and in vitro assessment

Background  Similar to other^99mTc-based infarct-avid agents,^99mTc-glucarate localizes in myocardial infarcts. Whether severely ischemic viable myocytes sequester^99mTc-glucarate is uncertain. To assess the infarct specificity, in vitro and in vivo studies were performed. Methods and Results  H9C2 embryonic rat cardiocytes cultured under normoxia (N) or hypoxia (H) for 24 hours in 7.5 μCi^99mTc-glucarate were compared with necrotic cardiocytes. Mean H/N ratio (3.0±0.004, mean±SD) was significantly less than that of the necrotic/N ratio (39.9±6.5,p<0.01). Reperfused myocardial infarction (MI) in 4 dogs confirmed by²⁰¹Tl, (0.5 to 1.0 mCi) scintigraphy were imaged serially, with simultaneously injected mixture of^99mTc-glucarate and¹¹¹In-antimyosin Fab. Infarcts were detected scintigraphically within 4 to 10 minutes with^99mTc-glucarate.¹¹¹In-antimyosin required more than 1 hour. Myocardial distribution at 5 hours showed a direct correlation between^99mTc-glucarate and¹¹¹In-antimyosin uptake (r=0.99,p<0.0001). Both^99mTc-glucarate (r=−0.777,p<0.0001) and¹¹¹In-antimyosin (r=−0.775,p<0.0001) were inversely related to²⁰¹Tl distribution. Conclusions  The near perfect correlation between^99mTc-glucarate and¹¹¹In-antimyosin uptake (r=0.99) in reperfused canine MI and the insignificant glucarate uptake by viable cardiocytes in vitro attest to the avidity of^99mTc-glucarate for the necrotic myocardium and favor its use as a specific early marker of myocyte necrosis in acute MI. Supported in part by SBIR grant 1R43-HL54410-01 and Molecular Targeting Technology, Inc.     

Multiple system atrophy variant with severe hippocampal pathology

The striatonigral and olivopontocerebellar systems are known to be vulnerable in multiple system atrophy (MSA), showing neuronal loss, astrogliosis, and alpha-synuclein-immunoreactive inclusions. MSA patients who displayed abundant neuronal cytoplasmic inclusions (NCIs) in the regions other than the striatonigral or olivopontocerebellar system have occasionally been diagnosed with variants of MSA. In this study, we report clinical and pathologic findings of MSA patients characterized by prominent pathologic involvement of the hippocampus. We assessed 146 consecutively autopsied MSA patients. Semi-quantitative analysis of anti-alpha-synuclein immunohistochemistry revealed that 12 of 146 patients (8.2%) had severe NCIs in two or more of the following areas: the hippocampal granule cells, cornu ammonis areas, parahippocampal gyrus, and amygdala. In contrast, the remaining 134 patients did not show severe NCIs in any of these regions. Patients with severe hippocampal involvement showed a higher representation of women (nine women/three men; Fisher's exact test, p = 0.0324), longer disease duration (13.1 ± 5.9 years; Mann–Whitney U-test, p = 0.000157), higher prevalence of cognitive impairment (four patients; Fisher's exact test, p = 0.0222), and lower brain weight (1070.3 ± 168.6 g; Mann–Whitney U-test, p = 0.00911) than other patients. The hippocampal granule cells and cornu ammonis area 1/subiculum almost always showed severe NCIs. The NCIs appeared to be ring-shaped or neurofibrillary tangle-like, fibrous configurations. Three of 12 patients also had dense, round-shaped NCIs that were morphologically similar to pick bodies. The patients with Pick body-like inclusions showed more severe atrophy of the medial temporal lobes and broader spreading of NCIs than those without. Immunohistochemistry for hyperphosphorylated tau and phosphorylated TDP-43 revealed minimal aggregations in the hippocampus of the hippocampal MSA patients. Our observations suggest a pathological variant of MSA that is characterized by severe involvement of hippocampal neurons. This phenotype may reinforce the importance of neuronal alpha-synucleinopathy in the pathogenesis of MSA.     

Association between pre‐pregnancy body mass index and gestational weight gain and perinatal outcomes in pregnant women diagnosed with gestational diabetes mellitus: The Japan Environment and Children's Study

Aims/IntroductionWe investigated the association between gestational diabetes mellitus (GDM) and perinatal outcomes stratified by pre‐pregnancy body mass index (BMI) and/or gestational weight gain (GWG).Materials and MethodsData from the national birth cohort in the Japan Environment and Children''s Study from 2011 to 2014 (n = 85,228) were used. Japan uses the GDM guidelines of the International Association of Diabetes and Pregnancy Study Groups. The odds ratios (ORs) of perinatal outcomes were compared between women with and those without GDM.ResultsThe OR (95% confidence interval) of having a small for gestational age infant in the GDM group with a pre‐pregnancy BMI of ≥25.0 kg/m² and insufficient GWG (<2.75 kg) was 1.78 (1.02–3.12). The OR of having a large for gestational age infant of the same BMI group with excessive GWG (>7.25 kg) was 2.04 (1.56–2.67). The OR of hypertensive disorders of pregnancy was higher in women with a BMI ≥18.5 kg/m² in the GDM group than in the non‐GDM group.ConclusionsLarge for gestational age and hypertensive disorders of pregnancy were associated with pre‐pregnancy BMI and GWG in either normal weight or overweight/obese women, and the relationship was strengthened when GDM was present. Women with GDM and a BMI of ≥25.0 kg/m² are at risk of having small for gestational age and large for gestational age infants depending on GWG.