Relationship of HIV RNA and cytokines in saliva from HIV-infected individuals

We measured levels of six cytokines and human immunodeficiency virus (HIV) RNA in saliva from HIV-seropositive individuals and compared salivary cytokine levels in HIV-seropositives and seronegatives. All of the six tested cytokines were detected in saliva although interleukin-1beta, interferon-gamma and interleukin-10 were detected more frequently (90%, 68% and 61% of samples, respectively) than interleukin-6, tumor necrosis factor-alpha and tumor necrosis factor-alpha receptor II (2-17%). There was no significant association between cytokine levels in saliva and plasma suggesting that cytokines were produced locally. Interferon-gamma levels were significantly higher in saliva from HIV-seropositives when compared to seronegatives while interleukin-10 levels were lower in seropositive saliva. Interleukin-10 levels were higher in individuals with low CD4 counts in the seropositive group. HIV RNA was detected in 29% of saliva samples from seropositives and there was a significant correlation between saliva and plasma HIV RNA levels. However, HIV RNA levels in saliva were not significantly associated with any of the saliva or plasma cytokine levels or with CD4 cell numbers. This study shows no association between inflammatory cytokine levels and HIV levels in saliva and suggests that saliva HIV levels are more influenced by blood HIV RNA levels than oral inflammation.     

Nociceptive neurons detect cytokines in arthritis

Proinflammatory cytokines are major mediators in the pathogenesis of diseases of joints such as rheumatoid arthritis and osteoarthritis. This review emphasizes that proinflammatory cytokines such as tumor necrosis factor-alpha, interleukin-1beta, interleukin-6 and interleukin-17 are also mediators of pain by directly acting on the nociceptive system. Proportions of nociceptive sensory neurons express receptors for these cytokines, and the application of cytokines rapidly changes the excitability, ion currents and second messenger systems of these neurons. By inducing persistent sensitization of nociceptive sensory neurons (C- and a proportion of Aδ-fibers) for mechanical stimuli in the joint (a process called peripheral sensitization), these cytokines significantly contribute to the persistent hyperalgesia typical for many disease states of the joint. In addition, the disease-associated release of cytokines in the spinal cord supports the generation of central sensitization. The therapeutic neutralization of proinflammatory cytokines thus not only reduces the process of inflammation but may directly reduce hyperalgesia and pain by reversing the neuronal effects of cytokines. It is emerging that different cytokines have different actions on neurons. The neutralization of tumor necrosis factor-alpha reduces both mechanical and thermal hyperalgesia of the joint. The neutralization of interleukin-1beta attenuates thermal hyperalgesia whereas the neutralization of interleukin-6 and interleukin-17 mainly reduces mechanical hyperalgesia. These different effects are partly explained by influencing different target molecules in sensory neurons. For example, in cultured sensory neurons tumor necrosis factor-alpha and interleukin-1beta upregulate the TRPV1 ion channel, which is involved in the transduction of heat stimuli, consistent with an effect of these cytokines in thermal hyperalgesia. By contrast, interleukin-17 upregulates the TRPV4 ion channel, which has a role in the transduction of mechanical stimuli. Thus, the analgesic potential of neutralizing cytokines seems to depend on which cytokine is mainly involved in the particular pain state.     

Differential regulation of phospholipase A2 by cytokines inhibiting bone formation and mineralization.

Treatment of fetal rat calvarial cells with interleukin-1 alpha, tumor necrosis factor-alpha, transforming growth factor-beta 1, or group II phospholipase A2 inhibits the number of bone nodules formed in long-term cultures. These same mediators also inhibit the mineralization of fully developed bone nodules in a time and dose-dependent fashion. The pro-inflammatory cytokines interleukin-1 alpha and tumor necrosis factor-alpha cause a dose-dependent induction of rat calvarial cell phospholipase A2-II mRNA levels, suggesting that their effects on bone formation may be mediated indirectly by activation of this enzyme. In contrast, transforming growth factor-beta 1, which has more potent effects on bone formation than interleukin-1 alpha or tumor necrosis factor-alpha, suppresses basal levels of phospholipase A2-II mRNA, indicating a different mechanism of action for this cytokine.     

Tumor necrosis factor and interleukin-1 induce activin A gene expression in a human bone marrow stromal cell line.

Activin A, a homodimer of the beta A chain, regulates hematopoiesis. In a human bone marrow-derived stromal cell line, KM-102, phorbol myristate acetate, tumor necrosis factor-alpha and interleukin-1 beta induced great increases in beta A chain mRNA levels and production of activin A activities. The phorbol ester-induced beta A chain gene expression was inhibited by cycloheximide and down regulation of protein kinase C, whereas the cytokine-induced expression was little affected by these treatments. These results indicate that the inflammatory cytokines directly stimulate beta A chain gene expression via protein kinase C-independent pathways.     

Expression of mRNA for interleukin-1beta, interleukin-6, tumor necrosis factor-alpha and macrophage migration inhibitory factor in HPA-axis tissues in Schistosoma mansoni-infected baboons (Papio cynocephalus)

Cytokines may regulate the function of the hypothalamic-pituitary-adrenal axis during schistosomiasis. This possibility was investigated in baboons experimentally infected with Schistosoma mansoni. Serum levels of corticotrophin-releasing hormone, adrenocorticotrophin, cortisol and dehydroepiandrosterone were confirmed to be decreased in infected baboons as previously shown. To explore if this effect is associated with specific expression of cytokines with endocrine activity, and are also associated with the pathology of the disease, Northern blots for interleukin-1beta, interleukin-6, tumor necrosis factor-alpha and macrophage migration inhibitory factor in hypothalamic-pituitary-adrenal axis tissues were performed. Infection induced interleukin-1beta gene expression in the hypothalamus, while interleukin-6 and migration inhibitory factor mRNAs were induced only in the pituitary and adrenal glands. Tumor necrosis factor-alpha gene expression was induced in the hypothalamus and the pituitary gland. Histopathological analysis of the hypothalamic-pituitary-adrenal axis tissues in infected and control baboons revealed no morphological differences between them. These results suggest that specific cytokines expressed in hypothalamic-pituitary-adrenal axis tissues could regulate hormone secretion during schistosomiasis.     

Amyloid beta and amylin fibrils induce increases in proinflammatory cytokine and chemokine production by THP-1 cells and murine microglia

Activated microglia surrounding amyloid beta-containing senile plaques synthesize interleukin-1, an inflammatory cytokine that has been postulated to contribute to Alzheimer's disease pathology. Studies have demonstrated that amyloid beta treatment causes increased cytokine release in microglia and related cell cultures. The present work evaluates the specificity of this cellular response by comparing the effects of amyloid beta to that of amylin, another amyloidotic peptide. Both lipopolysaccharide-treated THP-1 monocytes and mouse microglia showed significant increases in mature interleukin-1beta release 48 h following amyloid beta or human amylin treatment, whereas nonfibrillar rat amylin had no effect on interleukin-1beta production by THP-1 cells. Lipopolysaccharide-stimulated THP-1 cells treated with amyloid beta or amylin also showed increased release of the proinflammatory cytokines tumor necrosis factor-alpha and interleukin-6, as well as the chemokines interleukin-8 and macrophage inflammatory protein-1alpha and -1beta. THP-1 cells incubated with fibrillar amyloid beta or amylin in the absence of lipopolysaccharide also showed significant increases of both interleukin-1beta and tumor necrosis factor-alpha mRNA. Furthermore, treatment of THP-1 cells with amyloid fibrils resulted in an elevated expression of the immediate-early genes c-fos and junB. These studies provide further evidence that fibrillar amyloid peptides can induce signal transduction pathways that initiate an inflammatory response that is likely to contribute to Alzheimer's disease pathology.     

Regulation of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) by bone resorptive factors in osteoblastic cells

In addition to their stimulating function on osteoclastic bone resorption, bone resorptive factors may regulate proteinases and related factors in osteoblastic cells to degrade bone matrix proteins. This study investigated the regulation of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) by bone resorptive factors in the cultures of mouse osteoblastic MC3T3-E1 cells, mouse primary osteoblastic (POB) cells, and neonatal mouse calvariae. Expression of either MMP-2, -3, -9, -11, -13, and -14 or TIMP-1, -2, and -3 was detected in MC3T3-E1 cells and POB cells. When the bone resorptive factors parathyroid hormone, 1,25-dihydroxyvitamin D(3), prostaglandin E(2), interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha) were added to the cell cultures, MMP-13 mRNA levels were found predominantly to increase by all resorptive factors in the three cultures. mRNA levels of either MMP-3 and -9 or TIMP-1 and -3 were found to increase mainly by the cytokines IL-1beta and TNF-alpha. BB94, a nonselective MMP inhibitor, neutralized the (45)Ca release stimulated by these resorptive factors to an extent similar to that of calcitonin, strongly suggesting that bone resorptive factors function at least partly through MMP formation. We propose that MMP-13 mRNA expression in osteoblastic cells may play an important role in stimulating matrix degradation by both systemic and local resorptive factors, whereas either MMP-3 and -9 or TIMP-1 and -3 might modulate matrix degradation by local cytokines only.     

NF-kappaB-dependent cytokines in saliva and serum from patients with oral lichen planus: a study in an ethnic Chinese population

To access the potential roles of NF-kappaB-dependent pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), interleukin-6(IL-6), and interleukin-8(IL-8), in oral lichen planus (OLP), and to explore whether salivary detection of these cytokines is a better monitoring tool than serum for OLP, 30 Chinese patients with OLP and 30 age-sex-matched controls were enrolled in this study. Salivary and serum levels of cytokines were screened by enzyme immunoassay, and both salivary and serum levels of these cytokines were significantly increased in OLP patients in comparison with healthy subjects. Positive statistical correlations existed between these cytokines in serum and saliva. With regards to the subtypes of this illness, only salivary IL-8 levels in erosive form were remarkably inclined than that in reticular form. The results suggest that saliva-based test may provide a more cost-effective adjunctive tool for the detection of pro-inflammatory cytokines in OLP, and salivary IL-8 analysis may be a promising biomarker for OLP severity.     

Estrogen reduces pro-inflammatory cytokines in rodent adipose tissue: studies in vivo and in vitro.

Obesity is associated with an increased risk of developing insulin resistance, Type 2 diabetes, and cardiovascular disease. Reports have suggested that adipose tissue-derived cytokines such as tumor necrosis factor-alpha, interleukin-6 and interleukin-8 could be involved in the development of these health complications. Since estrogen has been suggested to attenuate the development of atherosclerosis and cardiovascular disease, we investigated whether ovariectomy affected the production and release of these three adipose tissue-derived cytokines with and without estrogen replacement in vivo and in vitro. Female Wistar rats were submitted to either a) ovariectomy, b) ovariectomy and estrogen replacement, or c) sham operation. After five months, animals were sacrificed and parametrial adipose tissue was removed and incubated for up to 24 hours with either interleukin-1beta (IL-1beta) (5 micro g/l), dexamethasone (50 nM) or estrogen (50 nM). Ovariectomy significantly increased interleukin-6 gene expression (p < 0.05) as well as interleukin-8 protein levels (p < 0.05) and gene expression (p < 0.05) in the adipose tissue, and estrogen replacement significantly reversed this increase (p < 0.05). However, no direct effects of estrogen were found in in vitro adipose tissue incubations. Neither ovariectomy nor estrogen replacement had any effects on tumor necrosis factor-alpha protein levels or gene expression. In conclusion, estrogen-deficient rats were found to have increased production of interleukin-6 and interleukin-8, which could be attenuated by estrogen-replacement. Since estrogen is suggested to be anti-atherosclerotic, this effect might be caused by a reduction in cytokine production from the adipose tissue.     

Regulation of human immune gene expression as influenced by a commercial blended Echinacea product: preliminary studies

Consumption of Echinacea at the first sign of symptoms has been clinically shown to reduce both the severity and duration of cold and flu. Quantitative polymerase chain reaction optimized for precision and reproducibility was utilized to explore in vitro and in vivo changes in the expression of immunomodulatory genes in response to Echinacea. In vitro exposure of THP-1 cells to 250 microg/ml of Echinacea species extracts induced expression (up to 10-fold) of the interleukin-1alpha, interleukin-1beta, tumor necrosis factor-alpha, intracellular adhesion molecule, interleukin-8, and interleukin-10 genes. This preliminary result is consistent with a general immune response and activation of the nonspecific immune response cytokines. In vivo gene expression within peripheral leukocytes was evaluated in six healthy nonsmoking subjects (18-65 years of age). Blood samples were obtained at baseline and on Days 2, 3, 5, and 12 after consuming a commercial blended Echinacea product, three tablets three times daily (1518 mg/day) for two days plus one additional dose (506 mg) on day three. Serum chemistry and hematological values were not different from baseline, suggesting that liver or bone marrow responses were not involved in acute responses to Echinacea. The overall gene expression pattern at 48 hr to 12 days after taking Echinacea was consistent with an antiinflammatory response. The expression of interleukin-1beta, tumor necrosis factor-alpha, intracellular adhesion molecule, and interleukin-8 was modestly decreased up through Day 5, returning to baseline by day 12. The expression of interferon-alpha steadily rose through Day 12, consistent with an antiviral response. These preliminary data present a gene expression response pattern that is consistent with Echinacea's reported ability to reduce both the duration and intensity of cold and flu symptoms.     

Serum proinflammatory mediators at different periods of therapy in patients with multiple myeloma

Multiple myeloma (MM) is a malignant disease characterized by the clonal proliferation of plasma cells within the bone marrow. Several cytokines have been demonstrated to be involved in the control of growth, progression, and dissemination of MM. We determined serum levels of interleukin-1beta (IL-1beta), soluble interleukin-2 receptor (sIL-2R), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-alpha), and C-reactive protein (CRP) in 14 newly diagnosed MM patients. The median age of the patients was 63.4 +/- 10.8 years and all of the patients were stage III (classified according to the Durie-Salmon classification). The same parameters were measured in 15 healthy controls. In addition, we also examined the effects of vincristine-adriamycin-dexamethasone (VAD) therapy on the same parameters and mediators as well as the relationship among the parameters in the same patient groups. The serum concentrations of TNF-alpha, IL-1beta, sIL-2R, IL-6, IL-8, and CRP (18.6 +/- 3.7 pg/mL, 10.1 +/- 2.8 pg/mL, 730 +/- 220 U/mL, 11.4 +/- 3.3 pg/mL, 23.9 +/- 8.3 pg/mL, and 49.9 +/- 19.5 mg/dL, resp) were significantly higher in newly diagnosed MM patients than in healthy controls (P < .0001). All of the parameters were found to be significantly reduced after chemotherapy. In conclusion, we found that after the VAD therapy, the level of these cytokines which are thought to play an important role in the pathogenesis of MM was significantly suppressed. This is the first study demonstrating strong impact of VAD treatment on circulating mediators of sIL-2R and IL-8 levels parameters.     

Cytokines in Gaucher's disease.

Gaucher's disease (GD) is characterized by hepatosplenomegaly, bone marrow infiltration, osteonecrosis, which may all be associated with the presence of pathological macrophages that contain undegraded glycosphingolipids. Levels of serum cytokines, which are soluble products of mononuclear phagocytes (MNP), were evaluated in 24 GD patients. Levels of interleukin-1beta (IL-1beta), interleukin-1 receptor antagonist (IL-1Ra), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and soluble interleukin-2 receptor (sIL-2R) in GD patients were significantly higher than in normal controls. We attempted to correlate cytokine levels with disease severity. Type I GD patients with more severe clinical manifestations had significantly higher levels of IL-1beta, IL-1Ra and IL-6, relative to type I patients with milder disease. Three patients homozygous for the 1448C mutation with neuropathic type III disease, had significantly higher levels of sIL-2R than type I patients or controls. We speculate that cytokine over-expression may relate to the pathophysiology of some of the clinical manifestations of GD. Thus, the elevated IL-1beta, TNF-alpha and IL-6 levels may induce the bone manifestations, the neutrophil chemotaxis and the increased incidence of hyper-gammaglobulinemia present in GD patients.     

Regulation of CA 125 expression in cultured human carcinoma cells

CA 125 shedding is not a constitutive and stable process but may be affected by cell cycle and cell proliferation as well as by various growth factors and cytokines. Interferons, interleukin-1 beta, tumor necrosis factor-alpha and transforming growth factor-alpha have been shown to induce while glucocorticoids and transforming growth factor-beta have been shown to suppress the release of the tumor marker CA 125 from ovarian carcinoma cells. Several endogenous as well as exogenous factors may affect CA 125 biosynthesis; however, a major question remains whether this observed modulation of CA 125 expression in vitro is of clinical importance.     

Neutrophils as firemen, production of anti-inflammatory mediators by neutrophils in a mixed cell environment

Neutrophils represent critical components of the innate immune system that bear primary responsibility for phagocytosis and killing of invading pathogens. Following stimulation of human whole blood, robust production of multiple cytokines and cytokine inhibitors occurs. We attempted to define the cell population responsible for the synthesis of different mediators by first stimulating whole blood and then isolating pure populations of granulocytes and monocytes. Monocytes produced mRNA coding for the classic pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and IL-6, while mRNA for these cytokines was not detectable in the isolated neutrophils. In contrast, neutrophils produce significant quantities of cytokine inhibitors such as the type 2 TNF soluble receptor and the IL-1 receptor antagonist. Both neutrophils and monocytes produced mRNA coding for IL-8. These data indicate that following stimulation of a mixed cell population the monocytes primarily produce pro-inflammatory mediators while the neutrophils synthesize a significant portion of the anti-inflammatory mediators. The neutrophils may be compared to firemen who bring the resources necessary to put out the flame of acute inflammation.     

Loss of TGF-beta dependent growth control during HSC transdifferentiation

Liver injury induces activation of hepatic stellate cells (HSCs) comprising expression of receptors, proliferation, and extracellular matrix synthesis triggered by a network of cytokines provided by damaged hepatocytes, activated Kupffer cells and HSCs. While 6 days after bile duct ligation in rats TGF-beta inhibited DNA synthesis in HSCs, it was enhanced after 14 days, indicating a switch from suppression to DNA synthesis stimulation during fibrogenesis. To delineate mechanisms modulating TGF-beta function, we analyzed crosstalk with signaling pathways initiated by cytokines in damaged liver. Lipopolysaccharide and tumor necrosis factor-alpha enhanced proliferation inhibition of TGF-beta, whereas interleukin-6, oncostatin M, interleukin-1alpha, and interleukin-1beta did not. Hepatocyte growth factor (HGF) counteracted TGF-beta dependent inhibition of DNA synthesis in quiescent HSCs. Since expression of c-met is induced during activation of HSCs and HGF is overrepresented in damaged liver, crosstalk of HGF and TGF-beta contributes to loss of TGF-beta dependent inhibition of DNA synthesis in HSCs.     

Loss of SHP-1 phosphatase alters cytokine expression in the mouse hindbrain following cochlear ablation

Inflammatory cytokines in the central nervous system are largely modulated by glial cells and influence neuronal responses to CNS injury. The protein tyrosine phosphatase SHP-1, an intracellular regulator of many cytokine signaling pathways, has been implicated in mediating the activation of glia. There is a direct correlation between abnormally activated microglia and neuron loss within the SHP-1 deficient motheaten (me/me) mouse auditory brainstem after afferent injury. In order to determine whether loss of SHP-1 creates an aberrant cytokine environment driving the abnormal activation of me/me microglia, the expression of interleukin-4 (IL-4), interleukin-10 (IL-10), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma) was examined by enzyme-linked immunosorbent assay (ELISA). Normal uninjured me/me mice showed lower IL-10 but higher IL-1beta levels compared to wild-type. Following unilateral cochlear ablation, there is decreased expression of IL-4 and IL-10 in me/me brains compared to wild-type, but IL-1beta is significantly increased. These findings indicate that decreases in anti-inflammatory cytokines, in combination with increased expression of the pro-inflammatory cytokine IL-1beta, may initiate a robust inflammatory reaction within the me/me brain contributing to the neuronal degeneration in the deafferented me/me auditory brainstem. SHP-1 may therefore play a role in limiting CNS inflammation following injury and disease.