Mindfulness and self-compassion in dermatological conditions: a systematic narrative review

OBJECTIVE

People affected by chronic skin conditions suffer from elevated levels of psychological distress. There is a need for evidence-based treatments that integrate medical care. Mindfulness and Self-compassion programs (MCBPs) have proven effective in chronic diseases. This systematic review aims to narratively synthesize the literature on mindfulness and self-compassion as traits and interventions in chronic skin conditions.

DESIGN

We searched four electronic databases for mindfulness and self-compassion trials and correlational studies in chronic skin conditions. We narratively synthetized results regarding the effects of mindfulness and self-compassion, both as traits and as interventions, on psychological and disease outcomes.

RESULTS

Thirteen studies were included in our review. Evidence from cross-sectional studies suggest that mindfulness and self-compassion are linked to lower psychological distress and better adjustment to the disease. MCBPs appear feasible for this population and can lower psychological distress, reduce disease severity and improve quality of life. Methodological issues limit conclusions on MCBP efficacy. Based on our analysis, we propose possible mechanisms that future research could explore.

CONCLUSIONS

The integration of MCBPs in the care process of chronic skin conditions appears promising. Definitive conclusions cannot be drawn due to a lack of strong evidence. Further studies with high methodological standards are needed.

[Insomnia--state of the science]

Diagnostic systems such as the international classification of diseases (ICD-10) or the diagnostic and statistical manual of mental disorders (DSM IV) have frequently been criticized as not adequately reflecting the complexity and heterogeneity of insomnia. Progress was made through the introduction of the international classification of sleep disorders (ICSD-2) and the research diagnostic criteria (RDC). The DSM-5 introduced the new category of insomnia disorder, thus relinquishing the traditional dichotomy of primary versus secondary insomnia. Recent basic research indicates that genetic and epigenetic factors are involved in the etiology of insomnia; the so-called three P model (i.e. predisposing, precipitating and perpetuating factors) and the hyperarousal concept have gained much attention in trying to explain the pathophysiology of insomnia. With respect to the cognitive-behavioral therapy of insomnia (CBT-I), a plethora of empirical evidence supports the first-line character of this type of treatment for insomnia. Unfortunately, CBT-I is still administered to only a minority of afflicted patients, probably due to a lack of resources in the healthcare system. As a consequence, stepped-care models to improve insomnia therapy encompass self-help programs, internet-based treatment avenues, community-centered activities (specially trained nurses) and as a last resort medical specialists/psychotherapists and sleep experts to deal with insomnia.

REM sleep instability--a new pathway for insomnia?

Chronic insomnia afflicts approximately 10% of the adult population and is associated with daytime impairments and an elevated risk for developing somatic and mental disorders. Current pathophysiological models propose a persistent hyperarousal on the cognitive, emotional and physiological levels. However, the marked discrepancy between minor objective alterations in standard parameters of sleep continuity and the profound subjective impairment in patients with insomnia is unresolved. We propose that "instability" of REM sleep contributes to the experience of disrupted and non-restorative sleep and to the explanation of this discrepancy. This concept is based on evidence showing increased micro- and macro-arousals during REM sleep in insomnia patients. As REM sleep represents the most highly aroused brain state during sleep it seems particularly prone to fragmentation in individuals with persistent hyperarousal. The continuity hypothesis of dream production suggests that pre-sleep concerns of patients with insomnia, i. e., worries about poor sleep and its consequences, dominate their dream content. Enhanced arousal during REM sleep may render these wake-like cognitions more accessible to conscious perception, memory storage and morning recall, resulting in the experience of disrupted and non-restorative sleep. Furthermore, chronic fragmentation of REM sleep might lead to dysfunction in a ventral emotional neural network, including limbic and paralimbic areas that are specifically activated during REM sleep. This dysfunction, along with attenuated functioning in a dorsal executive neural network, including frontal and prefrontal areas, might contribute to emotional and cognitive alterations and an elevated risk of developing depression.

Cytocidal activity of tumour necrosis factor: protection by protease inhibitors

The mechanism of the cytostatic and cytocidal activities of TNF was studied in human tumour cells. BT-20 breast and ME-180 cervical cancer cells were significantly growth-inhibited by TNF, but other cells were not. When protein synthesis was inhibited by cycloheximide, however, TNF was cytotoxic for all cells except BT-20 cells. This suggests that different mechanisms are responsible for the cytostatic and cytocidal activities of TNF. The sensitivity of different cell lines could not be correlated with the number or affinity of TNF receptors. Some protease inhibitors completely protected human and murine cells from TNF cytotoxicity. Inhibitors of chymotrypsin-like proteases were more effective than inhibitors of trypsin-like proteases. Reversible and irreversible inhibitors (such as alkylating compounds) were both protective. The cells were best protected when pretreated with inhibitors before the addition of TNF. When the protease inhibitors were removed the cells gradually lost their resistance to TNF cytotoxicity. The inhibitors did not interfere with the functioning of TNF-receptor complexes, since SK-MEL-109 melanoma cells treated with a protease inhibitor synthesized TNF-induced proteins. These findings suggest that a protease is involved in the cytocidal activity of TNF.

Degradation of unstable interleukin-1 alpha mRNA in a rabbit reticulocyte cell-free system. Localization of an instability determinant to a cluster of AUUUA motifs

Labeled transcripts of interleukin-1 alpha (IL-1 alpha) cDNA were rapidly degraded in incubations with rabbit reticulocyte lysate (RRL). In contrast, a transcript of superoxide dismutase cDNA was stable in control incubations. A transcript of the 3'-untranslated region (UTR) of IL-1 alpha was rapidly degraded while that of the 5'-UTR and coding region was stable. This degradative activity was present in the post-ribosomal supernatant. Degradation of the 3'-UTR transcript was inhibited by the addition of a large excess of an 80-base RNA containing four AUUUA repeats, but not by the same RNA without such repeats. This suggested that AUUUA motifs were responsible for the instability of the 3'-UTR transcript. The 80-base RNA did not act as a competitive substrate for a nuclease since it was not degraded. Partial transcripts of IL-1 alpha 3'-UTR were incubated with RRL to localize instability determinants. Transcripts containing at least three clustered AUUUA motifs were rapidly degraded, while transcripts containing four scattered AUUUA motifs were stable. To study the mechanism of RNA degradation, the RRL was passed through an affinity column that retained AUUUA-binding proteins. The flow-through or the fraction eluted from such a column were inactive, but the two fractions together degraded the 3'-UTR transcript. This indicated that proteins bound by the affinity column did not have nuclease activity but targeted this RNA for degradation.

Expression of interleukin-1 alpha and beta in early passage fibroblasts from aging individuals

Human diploid fibroblasts (HDFs) from newborn foreskin constitutively express interleukin-1 (IL-1) mRNA and protein after completing at least 70% (approximately 40 population doublings) of their in vitro life span. This IL-1 in turn induces the synthesis of specific proteins in aging HDFs. To determine whether IL-1 expression may be promoted by in vivo aging, we analyzed the expression of IL-1 and of inducible mRNAs in HDFs from two normal individuals 55 and 92 years old and in HDFs from a patient with premature aging caused by Werner's syndrome. By reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), we detected expression of IL-1 alpha and beta mRNA and protein in early passage HDFs from both normal individuals and the Werner's syndrome patient. These HDFs also expressed the IL-1-inducible mRNAs for stromelysin, plasminogen activator inhibitor type 2, manganous superoxide dismutase, and collagenase. These results suggest that an age-dependent expression of IL-1 occurs either in vivo or after a few cell divisions in vitro. Therefore, the fibroblast phenotype is modified by the expression of IL-1-inducible genes during aging.

Differential induction and decay of manganese superoxide dismutase mRNAs

Human manganese superoxide dismutase (MnSOD) is encoded by two mRNAs of 4 and 1 kb, respectively. These mRNAs are transcribed from the same gene and have an identical coding sequence, but differ in the 3' untranslated sequence because of alternate polyadenylation. Tumor necrosis factor-alpha (TNF) induced both 4- and 1-kb mRNAs in all the human cell lines examined. However, the relative expression of these mRNAs varied significantly among different cell lines after an 8-h treatment with TNF. Therefore, the time course of induction by TNF and the decay of MnSOD mRNAs after TNF removal were analyzed. The rate of accumulation of the 4-kb mRNA was initially much greater than that of the 1-kb mRNA, suggesting that the 4-kb mRNA was produced faster than the 1-kb mRNA. The rapid accumulation of the 4-kb mRNA was offset after a few hours by an enhanced rate of decay. The half-life of the 4-kb mRNA was approximately 2-4 h in different cells while that of the 1-kb mRNA was approximately 10-12 h. This different half-life of mRNAs that encode the same protein suggests that their relative expression is also regulated by a post-transcriptional mechanism affecting their turnover. Additional evidence supporting the differential decay of the two MnSOD mRNAs was obtained by incubation in a rabbit reticulocyte cell-free system; the 4-kb mRNA decayed rapidly while the 1-kb mRNA appeared to be stable.

Tumor necrosis factor increases stability of interleukin-1 mRNA by activating protein kinase C

The mRNAs coding for interleukin-1 alpha (IL-1 alpha) and IL-1 beta are constitutively transcribed but do not accumulate in human diploid fibroblasts and in fibrosarcoma cells. Treatment of these cells with tumor necrosis factor (TNF) induces accumulation of IL-1 mRNA by an unknown mechanism. This induction of IL-1 mRNA was investigated in HT-1080 cells. The induction was quite fast, with maximum levels of IL-1 alpha and beta mRNA reached 4 h after addition of TNF. Nuclear run-off experiment showed that TNF did not increase the rate of transcription of IL-1 mRNA. This mRNA was apparently unstable in untreated cells, but it accumulated in cycloheximide-treated cells. Phorbol esters induced IL-1 mRNA, suggesting that activation of protein kinase C was responsible for the accumulation of this mRNA. This hypothesis was confirmed by experiments with the PKC inhibitors staurosporine and calphostin C, which prevented the induction of IL-1 mRNA by TNF and accelerated the decay of this mRNA in cells pretreated with TNF. Both IL-1 alpha and IL-1 beta were detected in TNF-treated cells by Western blot analysis and enzyme-linked immunosorbent assay. These results indicate that the TNF-mediated induction of IL-1 can be entirely accounted for by stabilization of this mRNA.

Expression of messenger RNAs for complement inhibitors in human tissues and tumors

The mRNAs coding for three complement inhibitors produced by human cells, complement cytolysis inhibitor (CLI), decay-accelerating factor (DAF), and CD59, are characteristically distributed among normal tissues. High levels of CLI mRNA are expressed in tissues that express low levels of DAF mRNA and vice versa. Therefore, the expression of these mRNAs shows a mutually exclusive relationship, with the possible exception of the lung, where all these mRNAs are expressed. In contrast, CD59 mRNA is rather uniformly expressed in all tumor cell lines examined, whereas the mRNA for either of the two other complement inhibitors is overexpressed in some specific tumor cells, e.g., HeLa cells overexpress DAF mRNA, while A172 cells overexpress CLI mRNA. These two cell lines were resistant to antibody-dependent complement cytotoxicity. Expression of CLI and DAF mRNA was induced in cells treated with the antitumor drug N-(chloroetyl)-N'-cyclohexyl-N-nitrosourea; these cells became resistant to complement cytotoxicity. A similar pattern of expression was detected in tumor samples obtained during surgery, with a relatively uniform expression of CD59 mRNA and occasional overexpression of CLI or DAF mRNA. These findings suggest that overexpression of complement inhibitors mRNA and of the corresponding proteins may contribute to tumor cell resistance to complement-mediated cytotoxicity.

Expression of interleukin 1-inducible genes and production of interleukin 1 by aging human fibroblasts

The interleukin 1 (IL-1)-inducible mRNAs for plasminogen activator inhibitor type 2, manganese superoxide dismutase, and urokinase are overexpressed in old (greater than 70% of life-span completed) but not in young (less than 40% of life-span completed) human foreskin fibroblasts. Furthermore, the activity of this superoxide dismutase is greater in old than in young fibroblasts. IL-1 beta mRNA is detected by Northern blot analysis in old fibroblasts and its expression is further enhanced by a treatment with IL-1 alpha. IL-1 alpha and IL-1 beta mRNAs are detected in old foreskin and lung fibroblasts by a sensitive reverse transcription-PCR assay. IL-1 mRNA is consistently expressed after fibroblasts have completed 85% of their in vitro life-span; an assay with specific antibodies shows that IL-1 alpha is present in these fibroblasts. Prolonged treatment with IL-1 receptor antagonist decreases the levels of IL-1 alpha and of IL-1 alpha and IL-1 beta mRNAs. This observation suggests that IL-1 receptor antagonist inhibits an autocrine loop responsible for IL-1 expression. IL-1 mRNA accumulates in young fibroblasts treated with cycloheximide, suggesting that it is transcribed but unstable in these cells; accumulation of IL-1 mRNA in old fibroblasts may be due at least in part to increased stability. IL-1 alpha stimulates DNA synthesis in young fibroblasts but has progressively less effect as the cells age in culture. These data indicate that IL-1 is "constitutively" produced by aging fibroblasts and that IL-1 induces the expression of specific proteins in these cells. The mechanism for this constitutive production of IL-1 is explored in this paper.

Expression of porcine complement cytolysis inhibitor mRNA in cultured aortic smooth muscle cells. Changes during differentiation in vitro

Porcine smooth muscle cells (SMC) grown to a high density monolayer culture undergo a morphological transition in which the cells draw away from the substrate and form multicellular nodules. The cells within the nodule resemble SMC in the aortic media and in some atherosclerotic plaques. The process of nodule formation is associated with the enhanced production of a secreted 38-kDa glycoprotein. To characterize the 38-kDa protein and its expression, a cDNA clone (pc38K) was isolated by immunological screening of an expression library. The 1646-base pair cDNA contains a single open reading frame encoding 446 amino acids. This sequence shows 72% homology with the human complement cytolysis inhibitor (CLI), also called serum protein-40,40, and 68% identity with rat sulfated glycoprotein-2. Based on this homology, we refer to the protein encoded by pc38K as CLI. This polypeptide includes a potential signal sequence, seven glycosylation sites and 10 cysteines in two clusters of five each. Southern blot analysis reveals that a single copy gene encoding CLI is present in mammals and chicken. In Northern blot analysis of SMC RNA, pc38K hybridizes to a mRNA of about 1.9 kilobases that is preferentially expressed in nodular SMC. The steady state level of this mRNA increases as the cultures begin to form multilayered regions. High levels of the mRNA persist after the cells are trypsin-dissociated. Culture medium conditioned by nodular SMC also induces an increase of CLI mRNA. Analysis of RNA extracted from porcine tissues show the highest levels of CLI mRNA in brain and liver; lower levels are detected in other tissues, including the aorta. Possible functions for the CLI are discussed.

Reduced expression of manganese superoxide dismutase in cells resistant to cytolysis by tumor necrosis factor

Tumor necrosis factor (TNF) induces synthesis of manganese superoxide dismutase (MnSOD). It was previously shown that overexpression of MnSOD protected some mammalian cells from TNF cytotoxicity. The purpose of this study was to establish whether MnSOD was increased in cells selected for resistance to cytolysis by TNF in combination with cycloheximide. Melanoma SK-MEL-109 and HeLa cell-resistant variants were selected by repeated treatments with TNF and cycloheximide. The SK-MEL-109 variants had relatively low levels of MnSOD that were inducible by TNF. Surprisingly, the HeLa variants had very low levels of MnSOD that were poorly inducible by either TNF or interleukin-1 alpha. Therefore, an elevated level of MnSOD was not required to protect these cells from TNF-mediated cytolysis. The HeLa variants were more sensitive than parental cells to superoxide radical (O2-) generating compounds, such as paraquat or xanthine/xanthine oxidase. Pretreatment of these variants with TNF did not provide protection against damage by superoxide radicals.

Protection from tumor necrosis factor-mediated cytolysis by overexpression of plasminogen activator inhibitor type-2

Pretreatment of HT-1080 fibrosarcoma cells with tumor necrosis factor (TNF) induced resistance to the cytolytic activity of this cytokine in combination with cycloheximide. This resistance correlated with the synthesis of plasminogen activator inhibitor type-2 (PAI-2). HT-1080 cells were transfected with a PAI-2 expression vector in both sense and antisense orientation. The resistance to TNF-mediated cytolysis of transfected cell clones was correlated with the level of PAI-2 expression. Cells expressing antisense PAI-2 RNA showed reduced expression of PAI-2 and increased sensitivity to TNF-mediated cytolysis. Cells expressing constitutively PAI-2 were treated with TNF and cycloheximide to select cells with increased resistance to cytolysis and enhanced PAI-2 expression. PAI-2 gradually disappeared during a treatment with TNF and cycloheximide. This finding suggested that PAI-2 formed a complex with a target proteinase, which could be involved in mediating the cytolytic activity of TNF.

Modulation of neurite outgrowth in neuroblastoma cells by protein kinase C and platelet-activating factor

Previous reports have shown that thrombin and activators of protein kinase C (PKC) inhibit neurite outgrowth (NOG) in neuroblastoma cells cultured in serum-free medium. Therefore, we tested the hypothesis that PKC activation mediates the effect of thrombin on NOG in murine neuroblastoma NB-2a cells. After 2 h in serum-free medium, 70% of the cells displayed neurites; addition of 300 ng/ml thrombin reduced NOG to 24% within 1 h. This inhibition was reduced after NB-2a cells were pretreated for 24 h with 200 nM phorbol dibutyrate down-regulate PKC. Thrombin and phorbol 12-myristate 13-acetate inhibited NOG in an additive way and the protein kinase inhibitors H-7, H-8, and HA1004 reversed the effect of thrombin on NOG with a rank order of activity consistent with PKC inhibition. Furthermore, PKC was translocated from the cytosol to a membrane-bound form 5 to 10 min after addition of thrombin. These findings indicate that thrombin inhibits NOG through a PKC-dependent pathway. Thrombin stimulates the synthesis of the phospholipid platelet-activating factor (PAF) in some cells. However, NOG was markedly stimulated when PAF or its analogue carbamyl-PAF were added to NB-2a cells in medium with serum. Furthermore, the PAF receptor antagonist SRI 63072 inhibited NOG in NB-2a cells in serum-free medium. These cells accumulated PAF with kinetics similar to that of NOG inducPAF was synthesized by the de novo pathway, as shown by the incorporation of [3H]choline. These findings suggest that PAF is a mediator of NOG in NB-2a cells. Thrombin neither stimulates nor inhibits PAF synthesis in these cells.

Inhibition of the synthesis of platelet-activating factor by anti-inflammatory peptides (antiflammins) without methionine

Antiflammins are synthetic peptides corresponding to a region of similarity between uteroglobin and lipocortin I. These peptides inhibit synthesis of platelet-activating factor and release of arachidonic acid from neutrophils and macrophages stimulated by phagocytosis or tumor necrosis factor. Antiflammins containing methionine are inactivated readily in the absence of reducing agents. Novel antiflammins containing alanine or norleucine in place of methionine are inhibitory without added reducing agents, but only when stock solutions are heated to 45 degrees C. Heating may favor hydrophobic interactions between peptide molecules, thereby activating the antiflammins. These peptides are less inhibitory when added after cell stimulation, suggesting that they interfere with the activation of phospholipase A2.

Deadenylation and turnover of interferon-beta mRNA

The pathway of degradation of human interferon-beta (IFN-beta) mRNA was examined in murine C127 cells that carry an expression vector for this mRNA. The IFN-beta mRNA decayed with a half-life of approximately 45 min in actinomycin D-treated cells and became gradually shorter. This mRNA was superinduced in cycloheximide-treated cells, but it also became gradually shorter. However, apparently full-length species of IFN-beta mRNA accumulated after prolonged incubation with cycloheximide. The shortened IFN-beta mRNA species were partially deadenylated and less stable than full-length species. These findings suggest that at least two nuclease activities are involved in degrading IFN-beta mRNA; one deadenylates this mRNA and decays in cycloheximide-treated cells, while the other apparently breaks down deadenylated mRNA.

Posttranscriptional regulation of interferon mRNA levels in peritoneal macrophages

Low levels of beta interferon (IFN) mRNA are transcribed in freshly explanted murine peritoneal macrophages. Nuclear runoff transcription assays show that this "constitutive" IFN-beta-mRNA transcription does not increase in macrophages treated either with lipopolysaccharide or with IFN-gamma, which induce a marked accumulation of this mRNA and greatly increase IFN secretion. Therefore, these agents promote accumulation of IFN-beta mRNA by posttranscriptional mechanisms. The IFN-alpha 2 gene is also constitutively transcribed by macrophages, but the corresponding mRNA does not accumulate in lipopolysaccharide-treated cells.

The AU-rich sequences in the 3' untranslated region mediate the increased turnover of interferon mRNA induced by glucocorticoids

Different vectors were constructed that expressed the human interferon-beta (IFN-beta) mRNA constitutively and contained various deletions in the 3' untranslated region (UTR). AU-rich sequences in the 3' UTR were specifically deleted in two vectors. Cell lines secreting human IFN-beta were established by transfecting murine L929 cells with the vectors. These cells showed similar levels of IFN-beta mRNA and secreted comparable amounts of IFN-beta, indicating that the deletion of AU-rich sequences had no effect on the stability and little effect on the efficiency of translation of this mRNA. The synthetic glucocorticoid dexamethasone was previously shown to increase the turnover of IFN-beta mRNA. This activity of dexamethasone was clearly observed only in cells expressing IFN-beta mRNA with AU-rich sequences in the 3' UTR. The increased turnover of this mRNA occurred in the presence of cycloheximide; therefore, it did not require synthesis of new proteins. These findings suggest that glucocorticoids may activate a ribonuclease that degrades mRNAs containing AU-rich sequences in the 3' UTR.

Tumor necrosis factor alters cytoskeletal organization and barrier function of endothelial cells

Treatment of human umbilical cord vein endothelial cells with tumor necrosis factor results in marked changes in cell shape and cytoskeletal organization. After 4 h of treatment, these cells loose reciprocal contacts with the formation of intercellular gaps. This retraction reaches a maximum after 6 h when most stress fibers staining for F-actin disappear and vinculin becomes diffused in the cytoplasm. Such changes spontaneously reverse after 24 h in the presence of tumor necrosis factor or after 2 h of incubation in fresh medium. After treatment with tumor necrosis factor, endothelial monolayers become permeable to albumin because of gaps that form between cells. Normal human serum, plasma alpha 1-proteinase inhibitor and an anti-inflammatory peptide that decrease synthesis of platelet-activating factor inhibit the changes induced by tumor necrosis factor. Furthermore, receptor antagonists of platelet-activating factor have the same effect. These findings suggest that platelet-activating factor is a secondary mediator responsible for the changes in cell shape and cytoskeletal organization, and for the leakiness of endothelial monolayers.

Effects of different biological response modifiers on interferon expression in bacterial lipopolysaccharide (LPS)-responsive and LPS-hyporesponsive mouse peritoneal macrophages

We have previously shown that the antiviral state of explanted mouse peritoneal macrophages (PM) decays during in vitro culture and that this decay is much more rapid in Lpsd PM than it is in Lpsn PM. Moreover, Lpsn PM can transfer the antiviral state to other cells, whereas Lpsd PM cannot. In vitro treatment of Lpsn PM with different agents [i.e., bacterial lipopolysaccharide (LPS), interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha, macrophage colony-stimulating factor (M-CSF) and antibody to Mac-1 antigen] induced an antiviral state to vesicular stomatitis virus (VSV) which was inhibited by antibodies to IFN-beta. Treatment of Lpsn PM with LPS or IFN-gamma resulted in greater accumulation of IFN-beta mRNA, whereas no change in the barely detectable levels of IFN-alpha mRNA was observed. Marked accumulation of IFN-beta mRNA was also observed in PM after TNF-alpha treatment. M-CSF and IFN-gamma (but not LPS) also induced an IFN-mediated antiviral state in Lpsd PM. Low levels of spontaneous transcription of IFN-beta mRNA were detected in nuclei from Lpsd PM. Treatment of Lpsd PM with IFN-gamma for 3 h resulted in the accumulation of IFN-beta mRNA without any concomitant increase in the transcription of the IFN-beta gene, as determined by run-on transcription assays with isolated nuclei. The addition of as little as I international unit/ml of IFN-gamma to PM resulted in a 100-fold inhibition of VSV yield. As antibodies to IFN-alpha/beta inhibited only a portion of the IFN-gamma-induced antiviral state, such an antiviral state might reflect the synergism between IFN-gamma and endogenous IFN-beta. In fact, the addition of low doses of both IFN-gamma and IFN-beta to either Lpsn or Lpsd PM resulted in synergistic antiviral effects. In vivo treatment of Lpsd mice with granulocyte-macrophage (GM)-CSF, M-CSF, IFN-gamma or Newcastle disease virus rendered peritoneal cells capable of transferring an antiviral state. These results indicate that (i) various stimuli can induce IFN-beta production by PM, (ii) Lpsd PM spontaneously transcribe low levels of IFN-beta mRNA, even though they cannot transfer an antiviral state, (iii) different stimuli, but not LPS, induce a normal IFN response in Lpsd PM, (iv) IFN-gamma increases the accumulation of IFN-beta mRNA in Lpsd PM by post-transcriptional mechanisms and (v) IFN-gamma may act synergistically with endogenous IFN-beta in inducing a potent antiviral state to VSV in PM.

Tumor necrosis factor induces contraction of mesangial cells and alters their cytoskeletons

Cultures of human mesangial cells (MC) were established from the renal cortex of surgical specimen. The characteristic spindle-shaped or stellate appearance of MC was altered after treatment with tumor necrosis factor (TNF). After two hours, the MC retracted and lost reciprocal contacts. Furthermore, this treatment altered the cytoskeletal organization of MC, since a peripheral band of actin and stress fibers disappeared while the streaks of vinculin at focal contacts decreased. These changes were reversible when the MC were cultured in fresh medium. After five minutes of treatment with platelet activating factor (PAF), changes similar to those induced by TNF were observed. Inhibitors of PAF synthesis, such as plasma alpha 1-proteinase inhibitor and an anti-inflammatory peptide, blocked changes induced by TNF, PAF receptor antagonists inhibited changes induced by PAF and also by TNF. These results and the finding that MC are stimulated to produce PAF by TNF suggest that PAF is a secondary mediator of the changes in cell shape and cytoskeletal organization induced by this cytokine.

Nasal absorption of interferon: enhancement by surfactant agents

The effect of spraying the nasal mucosa with an aerosol of recombinant human interferon-alpha (IFN-alpha 2a) was studied in an animal model, the sheep, because cultures of sheep cells were found to be responsive to the antiviral activity of this IFN. Binding assays with 125I-labeled IFN-alpha 2a detected very few receptors in sheep nasal mucosa, but a membrane fraction prepared from this mucosa had abundant high-affinity receptors. Nasal mucosa homogenates were prepared from the turbinates of sheep that had been sprayed with IFN-alpha 2a aerosols, and the 2',5'-oligoadenylate (2-5A) activity induced in response was measured. To try to enhance the permeability of the mucosa, surfactant agents were added to the IFN and aerosols generated. There were measurable levels of 2-5A synthetase after aerosols with added sodium deoxycholate or, better, polyoxyethylene 9-lauryl ether. This latter surfactant was well tolerated in previous studies with intranasally administered insulin. The level of 2-5A synthetase induced was related to the dose of IFN, and the increased activity persisted up to 72 h after an IFN aerosol. These studies suggest that surfactant agents may make IFN aerosols much more effective for the prophylaxis of respiratory virus infections.

Tumour necrosis factor in serum and synovial fluid of patients with active and severe rheumatoid arthritis

Fifteen serum samples and 29 synovial fluids of patients with rheumatoid arthritis (RA) were examined for the presence of tumour necrosis factor (TNF). The assay for TNF was based on the cytotoxic activity of this cytokine for human melanoma cells in tissue culture. High concentrations of TNF were found in serum samples of patients with severe RA, who had increased erythrocyte sedimentation rate and serum alpha 2 macroglobulin, but decreased haemoglobin and serum iron concentrations. Tumour necrosis factor was also found in the synovial fluid of 16 out of 29 patients. High TNF concentrations were found in fluids with greater than 10(10) leucocytes/l. Tumour necrosis factor was not detected in the serum of normal subjects or in synovial fluid of patients with osteoarthritis. A mediator of inflammation, such as TNF, may contribute to the severity of RA.

Plasminogen activator inhibitor type-2 is a major protein induced in human fibroblasts and SK-MEL-109 melanoma cells by tumor necrosis factor

Tumor necrosis factor (TNF) induces the synthesis of two proteins of Mr 42 and 36 kDa in human fibroblasts and SK-MEL-109 melanoma cells. To identify these proteins, a lambda gt10 cDNA library was prepared from the mRNA of TNF-treated SK-MEL-109 cells. By screening this library, we found a cDNA that preferentially hybridized to TNF-induced RNA. Hybrid-selected mRNA was translated into a protein of 42 kDa; cDNA sequence analysis followed by a comparison with other known protein sequences identified this protein with plasminogen activator inhibitor, type-2 (PAI-2). After removal of TNF, PAI-2 mRNA turned over rapidly, with an apparent half-life of approximately 2.5 h. Addition of dexamethasone increased the turnover of this mRNA, suggesting that the level of PAI-2 mRNA could be regulated post-transcriptionally by glucocorticoids. PAI-2 was not secreted, but accumulated in fibroblasts continuously treated with TNF.

Positive and negative regulation of a tumor necrosis factor response in melanoma cells

Tumor necrosis factor (TNF) elicits a wide variety of responses in target cells by binding to cell surface receptors, but the signal transduced from these receptors in unclear. We examined the role of two different second messenger systems in the regulation of plasminogen activator inhibitor, type 2 (PAI-2) induction by TNF in SK-MEL-109 melanoma cells. Synthesis of PAI-2 and transcription of its mRNA could be induced by a protein kinase C (PKC) activator, phorbol myristate acetate. In addition, induction of PAI-2 synthesis by TNF was blocked by two PKC inhibitors, staurosporine and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride. The inhibitor of cyclic nucleotide-dependent protein kinases, N-[2-(methylamino)-ethyl]-5-isoquinoline sulfonamide dihydrochloride, was much less effective in decreasing PAI-2 synthesis. Staurosporine and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride also inhibited both TNF- and phorbol myristate acetate-induced PAI-2 mRNA accumulation. We measured the binding of 3H-labeled phorbol dibutyrate to membrane and cytosol fractions of TNF-treated SK-MEL-109 cells and found a transient redistribution of 3H-labeled phorbol dibutyrate binding from cytosol to membrane fractions in response to TNF. In contrast to the positive regulation by PKC in promoting TNF-induced PAI-2 synthesis cAMP inhibited this response. Pretreatment of cells with agents that raise intracellular cAMP levels completely abolished TNF-induced PAI-2 synthesis. Addition of cAMP-elevating agents during TNF induction could also block PAI-2 synthesis. PAI-2 mRNA accumulation in response to TNF was inhibited, but not completely abolished, by cAMP-elevating agents, suggesting that cAMP also exerted its inhibitory effect at the translation level. The positive regulation of a TNF response by PKC and its negative modulation by cAMP may provide a means for intracellular coordination of signals from interacting extracellular factors in regulating TNF responses in different target cells.

Antiinflammatory peptides (antiflammins) inhibit synthesis of platelet-activating factor, neutrophil aggregation and chemotaxis, and intradermal inflammatory reactions

Synthetic peptides corresponding to the region of highest similarity between human lipocortin I and rabbit uteroglobin inhibit phospholipase A2 and show potent antiinflammatory activity on the carrageenan-induced rat footpad edema. The peptide HDMNKVLDL (antiflammin-2) inhibits the synthesis of platelet-activating factor (PAF) induced by TNF or phagocytosis in rat macrophages and human neutrophils, and by thrombin in vascular endothelial cells. The peptide MQMKKVLDS (antiflammin-1) is less inhibitory than antiflammin-2 for macrophages and not inhibitory for neutrophils after a 5-min preincubation. This finding suggests that antiflammin-1 is inactivated by neutrophils secretory products, possibly oxidizing agents. Synthesis of PAF is inhibited by antiflammin-2 without an appreciable lag, but this inhibition is reversed when neutrophils or macrophages are washed and incubated in fresh medium. Therefore, antiflammins must be continuously present to inhibit PAF synthesis. Antiflammins block activation of the acetyltransferase required for PAF synthesis, suggesting that this enzyme is another target for the inhibitory activity of antiflammins. These peptides inhibit neutrophil aggregation and chemotaxis induced by complement component C5a. Antiflammin-2 suppresses the increase in vascular permeability and the leukocyte infiltration induced in rats by an Arthus reaction or by intradermal injection of rTNF and C5a.

Activators of protein kinase C enhance accumulation of interferon-beta mRNA in murine cell lines

Murine C127 fibroblasts carrying an expression vector for a human interferon gene (HuIFN-beta, under the control of a constitutive promoter) can be induced to produce murine (Mu) IFN by double-stranded (ds) RNA or virus infection. Fibroblasts treated with the protein kinase C activators 1-oleyl-2-acetylglycerol (OAG) or phorbol-12-myristate-13-acetate (PMA) secrete greater amounts of MuIFN than untreated cells, but the same amount of HuIFN-beta. Accordingly, the level of MuIFN-beta mRNA increases in the presence of protein kinase C activators whereas that of HuIFN-beta mRNA is unchanged. In time course experiments after induction with dsRNA, accumulation of MuIFN-beta mRNA is observed within 30 min in the presence of OAG, when this mRNA cannot be detected in control cells. The protein kinase C activators increase accumulation of MuIFN-beta mRNA, even in the presence of the inhibitor of protein synthesis cycloheximide. A similar increase in MuIFN-beta mRNA is observed in C243 fibroblasts treated with phorbol-12-myristate-13-acetate, but not in parental C127 cells. These findings suggest that protein kinase C does not promote synthesis of regulatory factors controlling transcription of IFN mRNA, but that it may be directly or indirectly involved in activation of such factors in some murine cell lines.

Multimeric structure of the tumor necrosis factor receptor of HeLa cells

The tumor necrosis factor (TNF) receptor of HeLa cells was solubilized in Triton X-100 and characterized by gel filtration, affinity labeling, and ligand blotting studies. Receptors solubilized with Triton X-100 eluted in gel filtration as a major peak of Mr = 330,000 and retained high affinity binding (KD = 0.25 nM). Affinity labeling of soluble receptor/125I-TNF complexes using the reversible, bifunctional bis[2-(succinimidooxycarbonyl-oxy)ethyl] sulfone resulted in the formation of cross-linked species of Mr = 310,000, 150,000-175,000, 95,000, and 75,000. The formation of these complexes was competitively inhibited by unlabeled TNF. Partial reversal of cross-linking in these complexes and their analysis by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) resolved 125I-TNF dimers cleaved from the 95,000 band and 125I-TNF monomer cleaved from the 75,000 band, providing evidence for a Mr approximately 60,000 subunit. In addition, the 95,000 and 75,000 bands were resolved as components of larger complexes (Mr = 150,000-175,000), which presumably contain two receptor subunits. The Mr 95,000 and 75,000 bands were also released from the Mr 310,000 complex by reduction with dithiothreitol, suggesting a role for disulfide bond stabilization. To investigate the association of the putative receptor subunits, Triton X-100 extracts from HeLa membranes were fractionated by SDS-PAGE without reduction and transferred electrophoretically to nylon membranes for TNF binding assays. Only two bands of Mr = 60,000 and 70,000 specifically bound TNF, and higher Mr binding activity was not observed. These results indicate that TNF receptors in HeLa cells are high molecular weight complexes containing Mr = 60,000 and 70,000 subunits each capable of binding TNF and that the complexes are primarily stabilized by non-covalent, hydrophobic interactions.

Tumor necrosis factor stimulates human neutrophils to release leukotriene B4 and platelet-activating factor. Induction of phospholipase A2 and acetyl-CoA:1-alkyl-sn-glycero-3-phosphocholine O2-acetyltransferase activity and inhibition by antiproteinase

Tumor necrosis factor stimulates polymorphonuclearneutrophils to synthesize leukotriene B4 and platelet-activating factor (PAF), but alpha 1-proteinase inhibitor and alpha 1-antichymotrypsin block this response. However, proteinases such as elastase and cathepsin G induce preferentially synthesis of PAF. An acetyltransferase required, together with phospholipase A2, in the remodeling pathway of PAF synthesis is activated in polymorphonuclearneutrophils stimulated by tumor necrosis factor and elastase. In contrast, 1-oleyl-2-acetylglycerol, a protein kinase C activator, promotes PAF formation by the de novo biosynthetic pathway without activating the acetyltransferase. Staurosporine, an inhibitor of protein kinase C, blocks PAF production apparently by inhibiting phospholipase A2. This suggests that diacylglycerols are involved in activating both pathway of PAF synthesis.