Circadian rhythm of acute phase proteins under the influence of bright/dim light during the daytime.

We investigated the influence of two different light intensities, dim (100 lx) and bright (5000 lx), during the daytime on the circadian rhythms of selected acute phase proteins of C-reactive protein (CRP), alpha1-acid glycoprotein (AGP), alpha1-antichymotrypsin (ACT), transfferin (TF), alpha2-macroglobulin (alpha2-m), haptoglobin (HP), and ceruloplasmin (CP). Serum samples were collected from 7 healthy volunteers at 4 h intervals during two separate single 24 h spans during which they were exposed to the respective light intensity conditions. A circadian rhythm was detected only in ACT concentration in the bright light condition. The concentration of ACT, a positive acute phase protein (APP), increased (significantly significant differences in the ACT concentration were detected at 14:00 and 22:00 h) and AGP showed a tendency to be higher under the daytime bright compared to dim light conditions. There were no significant differences between the time point means under daytime dim and bright light conditions for alpha2-M, AGP, Tf, Cp, or Hp. The findings suggest that some, but not all, APP may be influenced by the environmental light intensity.

Ibuprofen suppresses interleukin-1beta induction of pro-amyloidogenic alpha1-antichymotrypsin to ameliorate beta-amyloid (Abeta) pathology in Alzheimer's models.

Epidemiological and basic research suggests that nonsteroidal anti-inflammatory drugs (NSAIDs) should protect against the most common forms of Alzheimer's disease (AD). Ibuprofen reduces amyloid (Abeta) pathology in some transgenic models, but the precise mechanisms remain unclear. Although some reports show select NSAIDs inhibit amyloid production in vitro, the possibility that in vivo suppression of amyloid pathology occurs independent of Abeta production has not been ruled out. We show that ibuprofen reduced Abeta brain levels in rats from exogenously infused Abeta in the absence of altered Abeta production. To determine whether ibuprofen inhibits pro-amyloidogenic factors, APPsw (Tg2576) mice were treated with ibuprofen for 6 months, and expression levels of the Abeta and inflammation-related molecules alpha1 antichymotrypsin (ACT), apoE, BACE1, and peroxisome proliferator-activated receptor gamma) (PPARgamma) were measured. Among these, ACT, a factor whose overexpression accelerates amyloid pathology, was reduced by ibuprofen both in vivo and in vitro. IL-1beta, which was reduced in our animals by ibuprofen, induced mouse ACT in vitro. While some NSAIDs may inhibit Abeta42 production, these observations suggest that ibuprofen reduction of Abeta pathology may not be mediated by altered Abeta42 production. We present evidence supporting the hypothesis that ibuprofen-dependent amyloid reduction is mediated by inhibition of an alternate pathway (IL-1beta and its downstream target ACT).

Effect of interleukin-2 on peripheral blood mononuclear cell cytokine production and the hepatic acute phase protein response.

This study investigated the ability of recombinant interleukin-2 (IL-2) to modulate the ability of peripheral blood mononuclear cells (PBMCs) to stimulate an acute phase protein response in isolated human hepatocytes. The effect of IL-2 on the production of tumour necrosis factor-alpha (TNF) and interleukin-6 (IL-6) by PBMCs isolated from patients with gastrointestinal cancer, multiple organ failure, and healthy controls was also studied. The ability of supernatants from IL-2-treated PBMCs to elicit an acute phase response in hepatocytes was then investigated. IL-2 had no effect on IL-6 or TNF production by PBMCs isolated from any group in the presence or absence of bacterial lipopolysaccharide (LPS). Despite this, preincubation of PBMCs with IL-2 significantly reduced the potential of LPS-stimulated PBMC supernatants to stimulate production of alpha1 antichymotrypsin, alpha1-acid glycoprotein, and C-reactive protein by hepatocytes. These observations were not due to a direct effect of IL-2 on hepatocyte acute phase protein production. These findings suggest that in this model IL-2 may modulate PBMC-induced acute phase protein production through an IL-6 and TNF-independent pathway.

Induction of the alpha(1)-antichymotrypsin gene in the brain associated with TGF-beta1 deficiency or systemic administration of endotoxin.

We report that mRNA levels for alpha(1)-antichymotrypsin (ACT), a component of beta-amyloid plaques in Alzheimer's disease, are significantly increased in the brains of two different mouse models that develop inflammation: (1) acute inflammation caused by intraperitoneal injection with lipopolysaccharide (LPS) and (2) chronic inflammation in knockout mice lacking the anti-inflammatory cytokine transforming growth factor beta1 (TGF-beta1). While brain mRNA levels for the inflammatory cytokines TNFalpha, IL-1beta, and IL-6 were all elevated in the LPS-injected mice, only the mRNA for IL-1beta increased significantly in TGF-beta1-deficient mice. The transcription factor C/EBPbeta was strongly activated in the brains of both models. These results support the hypothesis that, through induction of the ACT gene in the brain, inflammation plays an important role during the development of Alzheimer's disease and that IL-1beta and C/EBPbeta may be involved in this process.

The non-steroidal anti-inflammatory drug tepoxalin inhibits interleukin-6 and alpha1-anti-chymotrypsin synthesis in astrocytes by preventing degradation of IkappaB-alpha.

Tepoxalin is a structurally and functionally novel non-steroidal anti-inflammatory drug (NSAID) with potent anti-inflammatory and analgesic properties. Apart from its inhibitory effect on cyclooxygenase activity, tepoxalin is able to inhibit production of cytokines in peripheral cells outside the CNS. No data, however, are available concerning the effects of this drug in the CNS. Since cytokines such as interleukin-1 (IL-1) or interleukin-6 (IL-6) as well as acute-phase proteins such as alpha1-anti-chymotrypsin (ACT) participate in the etiopathology of Alzheimer's disease (AD), we were interested whether tepoxalin is able to inhibit the synthesis of these immunomodulators in primary rat microglia and astrocytes as well as in the human astrocytoma cell line U373 MG. We found that tepoxalin markedly inhibits IL-1beta-induced IL-6 and ACT synthesis in astrocytes and the synthesis of IL-1beta and IL-6 in lipopolysaccharide (LPS)-stimulated microglial cells. Electrophoretic mobility shift and reporter gene assays revealed that tepoxalin exerts its inhibitory effect through the inhibition of nuclear factor kappaB (NF-kappaB), a transcription factor involved in the induction of IL-1, IL-6 and ACT gene expression. We show that inhibition of NF-kappaB activation by tepoxalin is mediated by preventing IkappaB-alpha degradation. Based on this inhibitory effect of tepoxalin on cytokine and ACT synthesis and the documented therapeutic efficacy of NSAIDs in AD, we conclude that tepoxalin may be of therapeutic benefit for the treatment of AD patients and should therefore be tested in clinical trials.

Ionizing radiation and TNF-alpha and stimulated expression of alpha1-antichymotrypsin gene in human squamous carcinoma cells.

Alpha-1 antichymotrypsin (ACT), a serine protease inhibitor, has been detected in several epithelial tumor cell types, but its role in response to therapy is not clear. We report here that exposure of primary head and neck squamous cell carcinoma (HNSCC)-derived cells (PCI-04A) to ionizing radiation (IR) or tumor necrosis factor-alpha (TNF-alpha) resulted in an increased level of ACT mRNA, although the induction patterns were different. IR treatment caused a transient stimulation of ACT mRNA, peaking at 3 h post-irradiation, whereas TNF-alpha-inducible ACT gene expression lasted for up to 24 h. The ACT mRNA was expressed in several epithelial and non-epithelial tumor cell types, and in different normal human tissues. In addition, when the ACT gene expression in PCI-04A cells was compared with the matched (from the same patient) metastatic HNSCC-derived cells (PCI-04B), increased steady-state level of the ACT mRNA was observed in PCI-04B cells. Taken together, these findings suggest that ACT may serve as an important marker for prognosis and therapy selection in HNSCC.

Effect of interleukin-4 on pro-inflammatory cytokine production and the acute phase response in healthy individuals and in patients with cancer or multiple organ failure.

1. This study investigates whether previously documented effects of interleukin-4 in down-regulating pro-inflammatory cytokine production by peripheral blood mononuclear cells (PBMCs) from healthy individuals would be reproducible in PBMCs isolated from patients with multiple organ failure (acute disease model) and gastrointestinal cancer (chronic disease model). The effects of interleukin-4 on the ability of PBMC supernatants to elicit an acute phase protein response from isolated human hepatocytes were also studied. 2. Incubation of PBMCs with interleukin-4 significantly reduced both spontaneous and lipopolysaccharide-induced production of tumour necrosis factor and lipopolysaccharide-induced interleukin-6 production, demonstrating that the PBMCs from patients with acute and chronic disease are not refractory to the effects of interleukin-4. The effects of interleukin-4 on the ability of PBMCs from the groups studied to elicit an acute phase response were complex and varied both between patient groups and individual acute phase proteins. Overall, interleukin-4 reduced the potential of PBMCs to stimulate production of the positive acute phase proteins C-reactive protein, alpha1-antichymotrypsin and alpha1-acid glycoprotein.3. This work emphasizes the pleiotropic nature of cytokines and the complex regulatory mechanisms which exist. The study illustrates the difficulties in devising in vivo intervention strategies using cytokines such as interleukin-4.

Cloning and characterization of the alpha 1-antichymotrypsin produced by human prostate tissue.

BACKGROUND: alpha 1-antichymotrypsin (ACT) forms stable complexes with prostate-specific antigen (PSA), a serine protease, and this complex is the major form of PSA in the blood circulation. alpha 1-antichymotrypsin occurs in the blood in approximately 10(5) molar excess to PSA, mainly due to hepatic production, but local prostatic production of ACT has been demonstrated by immunohistochemistry and in situ hybridization. The present study was performed to further characterize this prostate-produced ACT. METHODS: The nucleotide structure of the prostatic transcript was determined from ACT coding clones isolated from prostatic cDNA. The occurrence of a prostatic ACT transcript was analyzed by Northern blot. RT-PCR was used to detect ACT transcripts in cultured prostatic cancer cells. RESULTS: Screening of two prostatic cDNA libraries showed the frequency of ACT transcripts to be about 1 clone in 40,000. The cDNA sequence of prostatic ACT is identical to that of the previously published hepatic ACT. Northern blot analysis of mRNA extracted from prostatic tissue showed a single transcript of approximately 1.5 kb. RT-PCR analysis demonstrated an ACT transcript in cultured prostatic cancer cells. CONCLUSIONS: In this study we provide further evidence for a local, prostatic production of ACT. The cDNA sequence data suggest that the peptide backbone of prostatic ACT is identical to the protein derived from the liver, and thus may be functional as a protease inhibitor.

Expressions of a 68kDa-glycoprotein (GP68) and laminin in the mesodermal tissue of the developing mouse embryo.

Immunohistochemistry revealed initial expression of the stage-specific glycoprotein, GP68, in various mesenchymal tissue substructures of mouse embryos. During the 11-15th days of gestation, GP68 was localized in the primitive meninges, chondroblasts and perichondrium of pre-cartilaginous vertebral bodies and ribs, connective tissue cells of the dermis, the epicardium and endocardium of the heart, the epimysium and perimysium of skeleton musclature, and the basement membranes of splanchnic organs. Double staining for laminin expression indicated coincidental expression in identical tissue substructures. However, laminin was expressed in days 10-18 embryos and the neonate. Therefore, GP68 is coincidentally expressed with laminin in mesenchymal tissues between the 11th and 15th day of gestation, and may play a role as a laminin-associated protein. In the light of these results, a hypothesis concerning the relationship between these two proteins and the mechanisms of non-integrin laminin-associated proteins during normal embryogenesis is discussed further.

Interleukin-8 can mediate acute-phase protein production by isolated human hepatocytes.

During the course of studies designed to identify the role of cytokines in the reprioritization of hepatic protein synthesis associated with cachexia we detected a hepatocyte-stimulating moiety in the supernatants of pancreatic cancer cells that was unrelated to interleukin (IL)-6. This study identifies that moiety as IL-8 and investigates the role of IL-8 in the induction of acute-phase protein production. The human pancreatic cancer cell line MIA PaCa-2 produced >1 ng/ml of IL-8 per 24 h, and supernatants from this cell line induced C-reactive protein (CRP) production from isolated human hepatocytes. Addition of neutralizing anti-human IL-8 antibody to such supernatants produced almost complete inhibition of CRP production. The addition of recombinant human IL-8 to hepatocytes resulted in a dose-dependent increase in CRP, alpha1-acid glycoprotein, and alpha1-antichymotrypsin production and a decrease in the production of transferrin and prealbumin. This study demonstrates that recombinant or tumor-derived IL-8 can modulate acute-phase protein production from isolated human hepatocytes and from human hepatoma cells.

Expression of alpha-1-antichymotrypsin in prostate carcinoma.

Prostate specific antigen (PSA) is a glycoprotein with the enzymatic activity of serine protease, the gene which is encoded in the human glandular kallikrein gene locus. Catalytically active PSA released into serum may be inactivated by a complex formation with alpha 1ACT (ACT) and alpha 2MG (MG), two major protease inhibitors. The serum complex-to-total PSA ratio can be used as a marker for the differentiation between prostate carcinoma (PCa) and a benign lesion because of a significant elevation of PSA binding to ACT in PCa. Apparently higher immunohistochemical expressions of PSA and ACT have been reported in PCa of low Gleason scores when compared with benign lesions. The fact that only normal secretory epitheliums are capable of producing ACT was recently proved by immunohistochemical and in situ hybridization methods. Our immunohistochemical study of ACT showed a tendency toward stronger expression in high Gleason grade PCa than in low Gleason grade Pca. Prostate intraepithelial neoplasia (PIN), as well as BPH, seldom react to ACT. Expression of ACT in normal ducts or acini was influenced by their location. In a normal prostate, expression of ACT was predominantly in secretory epithelial cells, with a minority of basal cells and rarely in the interdigitating neuroendocrine cells. Whereas the potency of ACT production in epithelial cells almost always appeared to be suppressed under normal conditions, it was noted that a strong expression of ACT was apparent in the normal ducts or acini near a high grade carcinoma with a weak reaction to ACT. ACT expression is much more enhanced in high grade carcinomas and in the residual normal acini adjacent to carcinomas of low ACT expression, presumably representing scale down the elevated PSA.

Coordinate expression of group II phospholipase A2 and the acute-phase proteins haptoglobin (HP) and alpha1-anti-chymotrypsin (ACH) by HepG2 cells.

The early response to inflammation is characterized by the synthesis of a variety of proteins under cytokine and glucocorticoid control. During episodes of infection or inflammation, a secretory phospholipase A2 (sPLA2) appears in the circulation along with a variety of acute-phase proteins (APP), suggesting possible common regulatory elements amongst sPLA2 and APP. Using the human hepatoma line, HepG2, regulation of sPLA2 expression was examined in relation to synthesis of HP and ACH. The patterns of induction of sPLA2, HP and ACH were distinct for each of IL- 1, tumour necrosis factor (TNF) and IL-6, oncostatin M, IL-11 and leukaemia inhibitory factor. Dexamethasone had an enhancing effect on IL-6-induced expression of HP and ACH, but inhibited sPLA2 expression by 50%. Both 8-bromo-cAMP and dibutyryl cAMP increased sPLA2 expression (48.8-fold and 64.2-fold, respectively), whereas KT5720, an inhibitor of protein kinase A, down-regulated cytokine-induced sPLA2 synthesis by 51%. These data show that a panel of cytokines induced varying patterns of up-regulation of sPLA2, ACH and HP. Although dexamethasone potentiated IL-6-induced APP expression in HepG2 cells, it suppressed sPLA2 expression in a dose-dependent manner. In several respects, sPLA2 regulation is similar to that of HP and ACH, but a notable difference is the reciprocal effect of glucocorticoids on sPLA2 expression compared with that of ACH and HP.

Hepatocyte growth factor/scatter factor (HGF/SF) signals via the STAT3/APRF transcription factor in human hepatoma cells and hepatocytes.

Acute phase protein expression is regulated by a variety of cytokines such as IL-1, IL-6, IL-11, tumour necrosis factor alpha, interferon-gamma, oncostatin-M, leukemia inhibitory factor, ciliary neurotrophic factor and cardiotrophin-1. Presently, IL-6 is regarded as the most potent mediator of acute phase protein (APP) synthesis. It was shown that IL-6 and IL-6-type cytokines activate the so-called JAK/STAT pathway and finally regulate APP expression in liver cells. Since HGF/SF is also capable of regulating APP expression, we asked whether it might also signal via the JAK/STAT pathway. Here we show that incubation of human hepatocytes as well as hepatoma cells (HepG2) with HGF/SF results in activation of the transcription factor STAT3. This STAT3 activation after HGF/SF did not occur before 5-7 h and was maintained up to 28 h. These observations are in contrast to the rapid and transient activation of STAT1 and STAT3 mediated by IL-6.

Interleukin-1 beta and tumor necrosis factor-alpha induce expression of alpha 1-antichymotrypsin in human astrocytoma cells by activation of nuclear factor-kappa B.

The protease inhibitor alpha 1-antichymotrypsin (ACT) has been suggested to be involved in the etiology of Alzheimer's disease (AD). Increased levels of ACT have been found in serum and brains of AD patients, and ACT has been proposed to regulate beta-amyloid fibril formation in vitro. To gain insight into the regulation of ACT in the brain, we investigated the signal transduction pathways involved in ACT gene expression and protein synthesis in the human astrocytoma cell line U373. This cell line has previously been shown to respond with strong ACT synthesis on stimulation with interleukin-1 beta (IL-1 beta) or tumor necrosis factor-alpha (TNF alpha). Here, we describe that both IL-1 beta and TNF alpha activate the transcription factor nuclear factor-kappa B (NF-kappa B) via production of reactive oxygen intermediates resulting in ACT expression. In addition, we show that neither protein kinase C nor protein kinase A is involved in IL-1 beta- or TNF alpha-induced ACT expression. These results suggest that activation of NF-kappa B may be one possible cause of increased ACT levels in AD and provide a basis for the development of drugs used for the modulation of inflammatory processes occurring in AD.

Synthesis and secretion of active alpha 1-antichymotrypsin by murine primary astrocytes.

Activated astrocytes have been identified as the main source of the serine protease inhibitor alpha 1-antichymotrypsin (ACT), an acute phase protein that is tightly associated with amyloid plaques in Alzheimer's disease (AD) and in normal aged human and monkey brain. We analyzed the synthesis of ACT by cultured murine astrocytes in vitro. The murine astrocytes expressed an ACT-like antigen that crossreacted with antibodies to human ACT. The murine ACT-like protein is secreted by the astrocytes and is able to form an SDS-resistant complex with the serine protease cathepsin G, indicating that the secreted ACT is biologically active. We conclude that cultured primary astrocytes synthesize and secrete murine ACT in an active form. We, therefore, suggest that the ACT present within AD plaques is locally derived from plaque-associated activated astrocytes as a part of a glia-mediated local inflammatory response that is associated with the neurodegeneration seen in AD.

[Inclusion body myositis]. / La myosite à inclusions.

Inclusion body myositis has been recently recognized as a clinical entity although its exact definition remains uncertain. Initially considered to be an inflammatory dermatomyositis, inclusion body myositis can actually take on three specific forms: disseminated muscle atrophy and weakness, pseudopolymyositis, or pseudo-degenerative disease. Inclusion body myositis is different from non-inflammatory neuromuscular diseases with vacuoles. Abnormal deposits are seen within the muscle fiber may contain amyloid substance, beta-amyloid precursor, ubiquitin, antichymotrypsin, protein tau, apolipoprotein E and even prions. The signification of these deposits is unknown. Deletions in mitochondrial DNA have been demonstrated but do not appear to play a causal role. More and more hereditary forms are being recognized and certain may be related to an abnormality in chromosome 9.

Serine proteinase inhibitors in human skeletal muscle: expression of beta-amyloid protein precursor and alpha 1-antichymotrypsin in vivo and during myogenesis in vitro.

The balance of serine proteases and inhibitors in nerve and muscle is altered during programmed- and injury-induced remodeling. A serpin, alpha 1-antichymotrypsin (alpha 1-ACT), and Kunitz-inhibitor containing forms of the beta-amyloid precursor protein (beta APP) may be important components of this balance. In the present study, we analyzed their expression in primary cultures of human myogenic (satellite) cells that mimic myogenic differentiation using Western blotting and immunocytochemistry. In vitro results were compared to in vivo results from normal adult human skeletal muscle biopsies. Using an anti-alpha 1-ACT polyclonal antibody, we detected a 62 kDa immunoreactive band both in cultured human myogenic cells (mononucleated myoblasts as well as multi-nucleated myotubes) and in extracts of human muscle biopsies. With a polyclonal anti-beta APP antibody we found two bands (105 and 120 kDa) in myoblasts and myotubes in culture. However, the same antibody recognized only a single band at 92 kDa in biopsies. By immunocytochemistry, both alpha 1-ACT and beta APP were indistinctly present on localized to the surface of myoblasts in culture. In contrast, these inhibitors were dense on myotube surfaces, where they often formed distinct aggregates and frequently co-localized. In permeabilized muscle cells, alpha 1-ACT and beta APP appeared to be localized to the perikarya of both myoblasts and myotubes. Confirming previous results, both alpha 1-ACT and beta APP were present at the neuromuscular junction in human muscle sections. These developmental changes found during in vitro myogenesis for alpha 1-ACT and beta APP, both serine protease inhibitors, reinforce the hypothesis that regulation of the serine proteases and serine protease inhibitors plays an important role in neuromuscular differentiation.

IL-1 beta and TNF alpha, but not IL-6, induce alpha 1-antichymotrypsin expression in the human astrocytoma cell line U373 MG.

Cytokines such as interleukin-1 (IL-1) and interleukin-6 (IL-6) have previously been shown to participate in neurodegenerative processes including Alzheimer's disease. However, the molecular consequences of increased cytokine expression in the brain remain largely unknown. We have studied the effects of IL-1, IL-6 and TNF alpha on the expression of the acute-phase protein alpha 1-antichymotrypsin (ACT) in human astrocytoma cell lines. Both IL-1 and TNF alpha, but not IL-6, were able to induce ACT gene transcription and protein synthesis. The synthetic glucocorticoid dexamethasone enhanced cytokine-induced ACT mRNA expression and protein synthesis. We conclude that IL-1-induced expression of ACT may be part of the inflammatory response in the brain and may be involved in the pathology of Alzheimer's disease.

Regulation of alpha 1-antichymotrypsin synthesis in cells of epithelial origin.

Oncostatin M, interleukin-1 and the glucocorticoid analog, dexamethasone, have been identified as potent stimulators of alpha 1-antichymotrypsin production in various cells of epithelial origin. Although being able to act individually, these factors exerted a dramatic increase in alpha 1-antichymotrypsin synthesis when administrated in combination. Their stimulatory effect was independent of the levels of constitutive synthesis of this inhibitor, which was already high in lung- and breast- and low in skin-derived epithelial cells. Since alpha 1-antichymotrypsin controls chymotrypsin-like proteinases which are released during inflammation, these data support the concept that local synthesis of this inhibitor may be important in reducing tissue damage associated with this process.