Arterial Baroreflex Dysfunction Promotes Neuroinflammation by Activating the Platelet CD40L/Nuclear Factor Kappa B Signaling Pathway in Microglia and Astrocytes.

Arterial baroreflex (ABR) dysfunction has previously been associated with neuroinflammation, the most common pathological feature of neurological disorders. However, the mechanisms mediating ABR dysfunction-induced neuroinflammation are not fully understood. In the present study, we investigated the role of platelet CD40 ligand (CD40L) in neuroinflammation in an in vivo model of ABR dysfunction, and microglia and astrocyte activation in vitro. ABR dysfunction was induced in Sprague‒Dawley rats by sinoaortic denervation (SAD). We used ELSA and immunofluorescence to assess the effect of platelet CD40L on glial cell polarization and the secretion of inflammatory factors. By flow cytometry, we found that rats subjected to SAD showed a high level of platelet microaggregation and upregulation of CD40L on the platelet surface. The promotion of platelet invasion and accumulation was also observed in the brain tissues of rats subjected to SAD. In the animal model and cultured N9 microglia/C6 astrocytoma cells, platelet CD40L overexpression promoted neuroinflammation and activated M1 microglia, A1 astrocytes, and the nuclear factor kappa B (NFκB) signaling pathway. These effects were partially blocked by inhibiting platelet activity with clopidogrel or inhibiting CD40L-mediated signaling. Our results suggest that during ABR dysfunction, CD40L signaling in platelets converts microglia to the M1 phenotype and astrocytes to the A1 phenotype, activating NFκB and resulting in neuroinflammation. Thus, our study provides a novel understanding of the pathogenesis of ABR dysfunction-induced neuroinflammation and indicates that targeting platelet CD40L is beneficial for treating central nervous system (CNS) disorders associated with ABR dysfunction.

Analysis of a Panel of 48 Cytokines in BAL Fluids Specifically Identifies IL-8 Levels as the Only Cytokine that Distinguishes Controlled Asthma from Uncontrolled Asthma, and Correlates Inversely with FEV1.

We sought to identify cells and cytokines in bronchoalveolar lavage (BAL) fluids that distinguish asthma from healthy control subjects and those that distinguish controlled asthma from uncontrolled asthma. Following informed consent, 36 human subjects were recruited for this study. These included 11 healthy control subjects, 15 subjects with controlled asthma with FEV1≥80% predicted and 10 subjects with uncontrolled asthma with FEV1 <80% predicted. BAL fluid was obtained from all subjects. The numbers of different cell types and the levels of 48 cytokines were measured in these fluids. Compared to healthy control subjects, patients with asthma had significantly more percentages of eosinophils and neutrophils, IL-1RA, IL-1α, IL-1ß, IL-2Rα, IL-5, IL-6, IL-7, IL-8, G-CSF, GROα (CXCL1), MIP-1ß (CCL4), MIG (CXCL9), RANTES (CCL5) and TRAIL in their BAL fluids. The only inflammatory markers that distinguished controlled asthma from uncontrolled asthma were neutrophil percentage and IL-8 levels, and both were inversely correlated with FEV1. We examined whether grouping asthma subjects on the basis of BAL eosinophil % or neutrophil % could identify specific cytokine profiles. The only differences between neutrophil-normal asthma (neutrophil≤2.4%) and neutrophil-high asthma (neutrophils%>2.4%) were a higher BAL fluid IL-8 levels, and a lower FEV1 in the latter group. By contrast, compared to eosinophil-normal asthma (eosinophils≤0.3%), eosinophil-high asthma (eosinophils>0.3%) had higher levels of IL-5, IL-13, IL-16, and PDGF-bb, but same neutrophil percentage, IL-8, and FEV1. Our results identify neutrophils and IL-8 are the only inflammatory components in BAL fluids that distinguish controlled asthma from uncontrolled asthma, and both correlate inversely with FEV1.

CD4 costimulation is not required in a novel LPS-enhanced model of myasthenia gravis.

The potential of lipopolysaccharide (LPS) to induce antigen-specific B cell responses to acetylcholine receptor (AChR) in myasthenia gravis (MG) was evaluated in wild type (WT) and CD4-/- C57BL/6 mice. The WT mice immunized with AChR in LPS developed an MG-like disease (LPS-EAMG) similar to that induced by immunization with AChR in complete Freund's adjuvant (CFA-EAMG). CD4-/- mice were resistant to CFA-EAMG but susceptible to LPS-EAMG. LPS abrogated EAMG resistance in CD4-/- mice by increasing high-affinity anti-AChR IgG2b in sera and enhancing immune complex deposition in muscle.

Alternaria-induced release of IL-18 from damaged airway epithelial cells: an NF-κB dependent mechanism of Th2 differentiation?

BACKGROUND: A series of epidemiologic studies have identified the fungus Alternaria as a major risk factor for asthma. The airway epithelium plays a critical role in the pathogenesis of allergic asthma. These reports suggest that activated airway epithelial cells can produce cytokines such as IL-25, TSLP and IL-33 that induce Th2 phenotype. However the epithelium-derived products that mediate the pro-asthma effects of Alternaria are not well characterized. We hypothesized that exposure of the airway epithelium to Alternaria releasing cytokines that can induce Th2 differentiation. METHODOLOGY/PRINCIPAL FINDING: We used ELISA to measure human and mouse cytokines. Alternaria extract (ALT-E) induced rapid release of IL-18, but not IL-4, IL-9, IL-13, IL-25, IL-33, or TSLP from cultured normal human bronchial epithelial cells; and in the BAL fluids of naïve mice after challenge with ALT-E. Both microscopic and FACS indicated that this release was associated with necrosis of epithelial cells. ALT-E induced much greater IL-18 release compared to 19 major outdoor allergens. Culture of naïve CD4 cells with rmIL-18 induced Th2 differentiation in the absence of IL-4 and STAT6, and this effect was abrogated by disrupting NF- κB p50 or with a NEMO binding peptide inhibitor. CONCLUSION/SIGNIFICANCE: Rapid and specific release of IL-18 from Alternaria-exposed damaged airway epithelial cells can directly initiate Th2 differentiation of naïve CD4(+) T-cells via a unique NF-κB dependent pathway.

Ocular and generalized myasthenia gravis induced by human acetylcholine receptor γ subunit immunization.

INTRODUCTION: HLA-DQ8 transgenic mice develop ocular myasthenia gravis (oMG), which then progresses to generalized MG (gMG) when immunized with the human acetylcholine receptor (H-AChR) α subunit. Because the fetal AChR γ subunit is expressed in adult extraocular muscles, we anticipated that γ subunit immunization would generate an immune response to mouse AChR and induce MG in mice. RESULTS: H-AChR γ subunit immunization in HLA-DQ8 mice induced an autoimmune response to mouse AChR and led to the destruction of AChR in the neuromuscular junction (NMJ) by anti-AChR antibody and complement activation, and it triggered upregulation of AChR gene transcription. CONCLUSION: Our findings indicate that oMG may be induced by immunity to the AChR γ subunit.

Genetic deficiency of estrogen receptor alpha fails to influence experimental autoimmune myasthenia gravis pathogenesis.

Autoimmune myasthenia gravis (MG) is characterized by T cell and antibody responses to muscle nicotinic acetylcholine receptor (AChR). It is well known that MG as other autoimmune diseases is more prevalent in women than men and estrogen administration enhances experimental autoimmune MG (EAMG) severity. To determine whether estrogen influences EAMG pathogenesis through estrogen receptor alpha (ERα) activation, ERα knockout (KO) and wild-type (WT) C57BL/6 mice were immunized with AChR. ERα KO mice were equally susceptible to EAMG as WT mice and exhibited comparable antibody and immunopathological responses to AChR, suggesting a lack of involvement of ERα in EAMG pathogenesis.

Mannose-binding lectin pathway is not involved in myasthenia gravis pathogenesis.

Classical complement pathway factor, C4 is required for experimental autoimmune myasthenia gravis (EAMG) pathogenesis. C4 is also a central component of the mannose binding lectin (MBL) pathway suggesting that this pathway might also be involved in MG pathogenesis. However, MBL gene deficient mice displayed intact anti-acetylcholine receptor (AChR)-immune response and neuromuscular junction (NMJ) IgG and complement accumulation following AChR-immunization. Moreover, no significant difference was observed between the serum MBL levels of 77 anti-AChR antibody positive generalized MG patients and 105 healthy controls. Therefore, MBL pathway does not play a role in EAMG/MG pathogenesis.

Coliform contamination of vegetables obtained from popular restaurants in Guadalajara, Mexico, and Houston, Texas.

Food is the primary vehicle of transmission for traveler's diarrhea. We evaluated coliform contamination of vegetables from popular restaurants in Guadalajara, Mexico, and Houston, Texas. Contamination of vegetables in Guadalajara restaurants was widespread. Prevention of traveler's diarrhea by avoidance of "high-risk" foods may be unsuccessful, because contamination of foods may occur regardless of how they are prepared.

C5a is not involved in experimental autoimmune myasthenia gravis pathogenesis.

C5 deficient mice are highly resistant to experimental autoimmune myasthenia gravis (EAMG) despite intact immune response to acetylcholine receptor (AChR), validating the pivotal role played by membrane attack complex (MAC, C5b-9) in neuromuscular junction destruction. To distinguish the significance of C5a from that of C5b in EAMG pathogenesis, C5a receptor (C5aR) knockout (KO) and wild-type (WT) mice were immunized with AChR to induce pathogenic anti-AChR antibodies. In contrast with C5 deficient mice, C5aR KO mice were equally susceptible to EAMG as WT mice and exhibited comparable antibody and lymphocyte proliferation response to AChR implicating that C5a is not involved in EAMG development.

Rectal distension inhibits postprandial small intestinal motor activity partially via the adrenergic pathway in dogs.

OBJECTIVE: Rectal distension is known to induce numerous upper gastrointestinal symptoms. The aim of this study was to investigate the effects and mechanisms of rectal distension on small intestinal myoelectrical and motor activities in 8 dogs using a pair of intestinal electrodes and an intestinal fistula. MATERIAL AND METHODS: Experiment 1 entailed a 30-min baseline recording and a 30-min recording during rectal balloon distension at various volumes (60, 80, 100 and 120 ml) randomly. Experiment 2 comprised three sessions, each including a 30-min baseline recording, a 20-min recording after intravenous infusion of saline, phentolamine (3 mg/kg) or propranolol (3 mg/kg), respectively, and another 30-min recording during rectal balloon distending. RESULTS: 1) Rectal distension resulted in reduced intestinal motility in a dose-dependent manner (r=0.68, p<0.001). 2) The reduction in intestinal motility was significantly diminished when infusions of phentolamine (2.7+/-1.0 versus 8.4+/-1.5, p<0.01) or propranolol (3.7+/-1.4 versus 8.4+/-1.5, p<0.05) were given, suggesting partial involvement of the alpha- and beta-adrenergic pathways. 3) Rectal distension did not affect the percentage of normal 17-22 cycles/min intestinal slow waves (97.5+/-2.5 versus 93.0+/-5.3, p>0.05), or their dominant frequency (17.2+/-1.2 counts per minute (cpm) versus 17.7+/-1.0 cpm, p>0.05), or dominant power (-4.8+/-2.5 versus -8.2+/-2.9 dB, p>0.05). CONCLUSIONS: Rectal distension inhibits postprandial small intestinal motor activity in a distension volume-dependent manner in dogs, and this inhibitory effect is at least partially mediated via the alpha and beta adrenergic pathways and does not involve any alterations in intestinal slow waves.

Effects of intestinal electrical stimulation on postprandial small-bowel motility and transit in dogs.

BACKGROUND: Intestinal electrical stimulation (IES) with long pulses has been reported to inhibit motility as well as accelerate transit of continuous infusion. However, it is unknown whether there is a correlation between the IES-induced alterations in motility and transit and whether there is a difference in transit during IES between continuous infusion and bolus infusion. METHODS: The study was performed in 2 postprandial sessions (control and stimulation) in dogs with 2 pairs of serosal electrodes and 2 intestinal cannulas. Intestinal motility and transit with and without IES were measured by manometry and phenol red, respectively. RESULTS: IES significantly decreased intestinal motility and increased transit time. There was a significant correlation between motility index and transit during IES. CONCLUSIONS: IES inhibits both intestinal bolus motility and transit. There is correlation between motility and transit during IES.

Effect of enterokinetic prucalopride on intestinal motility in fast rats.

AIM: To evaluate the effects of prucalopride on intestinal prokinetic activity in fast rats and to provide experimental basis for clinical treatment of gastrointestinal motility diseases. METHODS: Gastrointestinal propulsion rate was measured by the migration rate of activated charcoal, which reflexes gastrointestinal motility function. 120 Spraque-Dawley rats were randomly divided into four groups and received an intravenous injection of physiological saline (served as control), prucalopride 1 mg/kg, prucalopride 2 mg/kg and cisapride 1 mg/kg, respectively. The gastrointestinal propulsion rate was measured 1, 2 or 4 hours after intravenous injection of the drugs. RESULTS: Significant accelerations of gastrointestinal propulsion rate in prucalopride 1 mg/kg and 2 mg/kg groups were found compared with control group at 2 and 4 hours(83.2 %+/-5.5 %, 81.7 %+/-8.5 % vs 70.5 %+/-9.2 %, P<0.01; 91.2 %+/-2.2 %, 91.3 %+/-3.9 % vs 86.8 %+/-2.6 %, P<0.01). The gastrointestinal propulsion rates at 1, 2 or 4 hours were faster in prucalopride 1 mg/kg and 2 mg/kg groups than in cisapride group (84.0 %+/-11.7 %, 77.1 %+/-11.9 % vs 66.3 %+/-13.6 %, P<0.01, P<0.05; 83.2 %+/-5.5 %, 81.7 %+/- 8.5 % vs 75.4 %+/-5.9 %, P<0.01, P<0.05; 91.2 %+/-2.2 %, 91.3 %+/-3.9 % vs 88.6 %+/-3.5 %,P<0.05, P<0.05). No difference of gastrointestinal propulsion rate was found between prucalopride 1 mg/kg group and prucalopride 2 mg/kg group (P>0.05). CONCLUSION: Prucalopride accelerates intestinal motility in fast rats, and has no dose dependent effect.

[Changes of ultrastructure characteritics of Cajal interstitial cell in intestinal tract of diabetic rats].

OBJECTIVE: This study is to clarify the changes of the ultrastructure characteristic of Cajal interstitial cell of diabetic rats intestinal tract. METHODS: Male SD rats were randomly divided into two groups: group A (diabetic), group B (control). 45 mg/kg Alloxan was injected into the group A, group B was injected with saline instead, after 12 weeks, the tissues of small intestine, colon were observed through electric telescope. RESULTS: The major change of Cajal interstitial cell of diabetic rat were showed as below: the number of the gap junctions between Cajal interstitial cell and neuron cells, between Cajal interstitial cell and myocyte, and between themselves were decreased significantly, and the structure of those gap junctions rested were also damaged; mitochondrion was swelling, vacuoles, dissolving; cytoplasm was dissolving, vacuoles were formed; the organelle were decreased. CONCLUSIONS: The ultrastructure of Cajal interstitial cell of diabetic had striking changes, these changes are closely related with the changes of their function, so it is very possible that these changes are one of the mechanisms of diabetic gastrointestinal dysfunction.