Pneumocystis activates human alveolar macrophage NF-kappaB signaling through mannose receptors

Alveolar macrophages (AM) represent important effector cells in the innate immune response to the AIDS-related pathogen Pneumocystis, but the early AM host defense signaling events are poorly defined. Using AM from healthy individuals, we showed in the present study that Pneumocystis organisms stimulate AM NF-kappaB p50 and p65 nuclear translocation in a time-dependent and multiplicity-of-infection-dependent manner as determined by electrophoretic mobility shift assay and immunofluorescence microscopy and that NF-kappaB nuclear translocation is associated with I-kappaB phosphorylation. Importantly, competitive inhibition of mannose receptor and targeted short interfering RNA-mediated gene suppression of mannose receptor mRNA and protein is associated with complete elimination of NF-kappaB nuclear translocation in response to Pneumocystis. Furthermore, human immunodeficiency virus (HIV) infection of AM (as a model human disease state of reduced AM mannose receptor expression and function) inhibits Pneumocystis-mediated NF-kappaB nuclear translocation and is associated with reduced I-kappaB phosphorylation and reduced interleukin-8 (IL-8) release. In contrast, NF-kappaB nuclear translocation and IL-8 release in response to lipopolysaccharide are intact in AM from both healthy and HIV-infected individuals, indicating that the observed impairment is not a global disturbance of the NF-kappaB pathway. Thus, in addition to phagocytic and endocytic effector functions, the present study identifies mannose receptors as pattern recognition receptors capable of NF-kappaB activation in response to infectious non-self challenge. AM mannose receptor-mediated NF-kappaB activation may represent an important mechanism of the host cell response to Pneumocystis, and altered NF-kappaB activation in the context of HIV infection may impair a critical innate immune signaling response and may contribute to pathogenesis of opportunistic lung infections.     

Hyperprolactinemia does not influence hypothalamic-pituitary-adrenocortical function during hypoglycemia in women

Elevated plasma prolactin and mild hypocortisolemia have been observed in patients with rheumatic disorders. This study was designed to assess the potential inhibitory effect of hyperprolactinemia on hypothalamic-pituitary-adrenocortical function. Hypoglycemia was induced by intravenous insulin injection (0.1 IU/kg) in 10 female volunteers of fertile age during their follicular phase twice: 60 min after either domperidone (10 mg orally) or placebo administration. Blood samples were collected from an indwelling catheter inserted into the cubital vein at -60, 0, 30, 45, 60 and 90 min. The concentrations of prolactin, adrenocorticotropic hormone (ACTH), cortisol, epinephrine, norepinephrine and glucose were measured in plasma. Domperidone administration significantly increased plasma prolactin concentrations (71 +/- 11 ng/ml vs. 14 +/- 6 ng/ml; p <0.001), while basal plasma concentrations of ACTH, cortisol, norepinephrine and epinephrine were unaffected. Insulin-induced hypoglycemia resulted in a significant rise in the mean plasma ACTH levels from 10 +/- 1 pg/ml (domperidone) and 11 +/- 1 pg/ml (controls) to 148 +/- 19 pg/ml (domperidone) and 139 +/- 12 pg/ml (controls) at 45 min (p < 0.001), in plasma cortisol from 407 +/- 62 nmol/l (domperidone) and 391 +/- 42 nmol/l (controls) to 925 +/- 60 nmol/l (domperidone) and 810 +/- 52 nmol/l (controls) at 60 min (p < 0.001), and in plasma epinephrine from 40 +/- 26 pg/ml (domperidone) and 16 +/- 3 pg/ml (controls) to 274 +/- 55 pg/ml (domperidone) and 352 +/- 61 pg/ml (controls) at 30 min; (p < 0.001). The significant increase in ACTH, cortisol and epinephrine responses to hypoglycemia was similar in both groups. We observed mild norepinephrine response to hypoglycemia but this was irrespective of the medication. In conclusion, pharmacologically-induced hyperprolactinemia did not induce significant changes of hypothalamic-pituitary-adrenocortical function and did not influence sympathoadrenal activity in healthy young women.     

The thioredoxin system from Streptomyces coelicolor

This paper describes the cloning, purification and characterization of thioredoxin (TrxA) and thioredoxin reductase (TrxR) from bacterial strain Streptomyces coelicolor . The genes of S. coelicolor encoding TrxA and TrxR were amplified by polymerase chain reaction, inserted into pET expression vector and used to overexpress these proteins in Escherichia coli . TrxA and TrxR were produced as the hexahistidine fusion proteins and were recovered from the cytoplasm as the soluble proteins. The activity of the purified recombinant proteins was demonstrated. The activity of TrxA was shown by efficient reduction of insulin and activity of NADPH-dependent TrxR was revealed by catalyses of 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB) reduction reaction. The reduction reaction was fully dependent upon the presence of TrxA as intermediate electron carrier with the pH optimum 7.5 and the temperature optimum 29 degrees C. Km value of TrxR for TrxA was 0.217 +/- 0.02 microM.     

Biomarkers to detect central dopamine deficiency and distinguish Parkinson disease from multiple system atrophy

ObjectiveBiomarkers are increasingly important to diagnose and test treatments of neurodegenerative diseases such as Parkinson disease (PD). This study compared neuroimaging, neurochemical, and olfactory potential biomarkers to detect central dopamine (DA) deficiency and distinguish PD from multiple system atrophy (MSA).MethodsIn 77 PD, 57 MSA, and 87 control subjects, radioactivity concentrations in the putamen (PUT), caudate (CAU), occipital cortex (OCC), and substantia nigra (SN) were measured 2 h after 6-[¹⁸F]fluorodopa injection, septal myocardial radioactivity measured 8 min after 6-[¹⁸F]fluorodopamine injection, CSF and plasma catechols assayed, or olfaction tested (University of Pennsylvania Smell Identification Test (UPSIT)). Receiver operating characteristic curves were constructed, showing test sensitivities at given specificities.ResultsPUT:OCC, CAU:OCC, and SN:OCC ratios of 6-[¹⁸F]fluorodopa-derived radioactivity were similarly low in PD and MSA (p < 0.0001, p < 0.0001, p = 0.003 compared to controls), as were CSF dihydroxyphenylacetic acid (DOPAC) and DOPA concentrations (p < 0.0001, each). PUT:SN and PUT:CAU ratios were lower in PD than in MSA (p = 0.004; p = 0.005). CSF DOPAC correlated positively with PUT:OCC ratios (r = 0.61, p < 0.0001). Myocardial 6-[¹⁸F]fluorodopamine-derived radioactivity distinguished PD from MSA (83% sensitivity at 80% specificity, 100% sensitivity among patients with neurogenic orthostatic hypotension). Only PD patients were anosmic; only MSA patients had normal olfaction (61% sensitivity at 80% specificity).ConclusionsPD and MSA feature low PUT:OCC ratios of 6-[¹⁸F]fluorodopa-derived radioactivity and low CSF DOPAC and DOPA concentrations, cross-validating the neuroimaging and neurochemical approaches but not distinguishing the diseases. PUT:SN and PUT:CAU ratios of 6-[¹⁸F]fluorodopa-derived radioactivity, cardiac 6-[¹⁸F]fluorodopamine-derived radioactivity, and olfactory testing separate PD from MSA.     

Combined air pollution particle and ozone exposure increases airway responsiveness in mice

We investigated whether coexposure to inhaled ambient particles and ozone affects airway responsiveness (AR, measured as enhanced pause, Penh) and allergic inflammation (AI) in a murine model of asthma. Ovalbumin-sensitized mice were challenged with either ovalbumin ("asthmatic") or phosphate-buffered saline (PBS) aerosols for 3 successive days. Immediately after daily challenge, mice were exposed for 5 h to concentrated ambient particles (CAPs), or 0.3 ppm ozone, or both, or neither (n > or = 61/group, 12 experiments). Exposure to CAPs alone or coexposure to CAPs + O(3) caused an increase in Penh in both normal and "asthmatic" mice. These responses were transient and small, increasing approximately 0.9% per 100-microg/m(3) increase in CAPs. Analysis of the effects of particle composition on AR revealed an association between the AlSi particle fraction and increased AR in "asthmatic" mice exposed to ozone and particles. No effects of pollutants on AI were noted. We conclude that (1) particle exposure causes an immediate, short-lived (<24 h) increase in AR in mice; (2) these responses are small; and (3) changes in AR may be correlated with specific elements within the particle mixture.     

Pharmacological hyperprolactinemia attenuates hydrocortisone-induced expression of CD11b on human CD8+ cells in vivo

OBJECTIVE: To study the short-term influences of pharmacologic hyperprolactinemia on hydrocortisone (HC)-induced effects on selected immune parameters. METHODS: A single dose of HC (40 mg per os) was administered to eleven healthy female volunteers 1 h after domperidone (10 mg per os) or placebo administration. Immune cell subsets and expression of adhesion molecules was assessed by flow cytometry at baseline and 4 and 6 h after HC administration. Intracellular staining of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) production in CD4+ lymphocytes after phorbol myristate acetate and ionomycin stimulation was performed at the same time points. RESULTS: HC administration was followed by a significant increase in cortisol levels, numbers of leukocytes and granulocytes and the percentage of CD16+, CD19+, CD11a+, CD11a+CD8+, CD11b+ and CD11b+CD8+ cells. The number of lymphocytes and monocytes and the percentage of CD3+, CD4+, CD4+/CD8+ ratio, CD62L+, CD54+ and CD54+CD16+ cells decreased, while the percentage of CD8+ cells was unaffected. Domperidone administration resulted in a significant increase in prolactin (PRL) concentrations. During hyperprolactinemia, the HC-induced increase in CD11b+CD8+ cells was significantly (p < 0.05) attenuated at 4 h. HC-induced changes in other immune parameters remained unaffected. No significant changes in the intracellular production of IL-4 and IFN-gamma in CD4+ lymphocytes were observed after a single dose of HC alone or during hyperprolactinemia. CONCLUSIONS: This study shows an attenuated HC-induced increase in CD11b+CD8+ cells in the peripheral blood of healthy females during hyperprolactinemia. Our in vivo observations suggest that short-term interactions occur between PRL and glucocorticoids, affecting selected immune functions. Further studies are needed for confirmation of these results.     

Role of the immune system in the pathogenesis,prevention and treatment of Alzheimer's disease

The dysregulation in the metabolism of beta-amyloid precursor protein and consequent deposition of amyloid-beta (Abeta) has been envisaged as crucial for the development of neurodegeneration in Alzheimer's disease (AD). Amyloid deposition begins 10-20 years before the appearance of clinical dementia. During this time, the brain is confronted with increasing amounts of toxic Abeta peptides and data from the last decade intriguingly suggest that both the innate and the adaptive immune systems may play an important role in the disorder. Innate immunity in the brain is mainly represented by microglial cells, which phagocytose and degrade Abeta. As the catabolism of Abeta decreases, glial cells become overstimulated and start to produce substances that are toxic to neurons, such as nitric oxide and inflammatory proteins. Pro-inflammatory cytokines can be directly toxic or stimulate Abeta production and increase its cytotoxicity. A therapeutic possibility arises from clinical studies, which demonstrate that nonsteroidal anti-inflammatory drugs (NSAIDs) may delay the onset and slow the progression of AD. Recent data show that in addition to the suppression of inflammatory processes in the brain NSAIDs may decrease the production of Abeta peptides. The role of adaptive immunity lies mainly in the fact that Abeta can be recognised as an antigen. Immunisation with Abeta peptides and peripheral administration of Abeta-specific antibodies both decrease senile plaques and cognitive dysfunction in murine models of AD. A recent trial in humans seems still to be hampered by adverse effects. As adaptive immunity decreases with aging while innate immunity remains intact, immunotherapy for AD will have to be adapted to this situation. Strategies that combine vaccination and inflammatory drug treatment could be considered.     

Short-term effects of continuous positive airway pressure on oxidative stress in severe sleep apnea

Sleep and Breathing - Obstructive sleep apnea (OSA) is associated with oxidative stress that is involved in the pathogenesis of cardiovascular and metabolic complications. The concentrations of...