PAC1 deficiency reduces chondrogenesis in atherosclerotic lesions of hypercholesterolemic ApoE-deficient mice

BACKGROUND

Induction of chondrogenesis is associated with progressive atherosclerosis. Deficiency of the ADCYAP1 gene encoding pituitary adenylate cyclase-activating peptide (PACAP) aggravates atherosclerosis in ApoE deficient (ApoE-/-) mice. PACAP signaling regulates chondrogenesis and osteogenesis during cartilage and bone development. Therefore, this study aimed to decipher whether PACAP signaling is related to atherogenesis-related chondrogenesis in the ApoE-/- mouse model of atherosclerosis and under the influence of a high-fat diet.

METHODS

For this purpose, PACAP-/-/ApoE-/-, PAC1-/-/ApoE-/-, and ApoE-/- mice, as well as wildtype (WT) mice, were studied under standard chow (SC) or cholesterol-enriched diet (CED) for 20 weeks. The amount of cartilage matrix in atherosclerotic lesions of the brachiocephalic trunk (BT) with maximal lumen stenosis was monitored by alcian blue and collagen II staining on deparaffinized cross sections. The chondrogenic RUNX family transcription factor 2 (RUNX2), macrophages [(MΦ), Iba1+], and smooth muscle cells (SMC, sm-α-actin) were immunohistochemically analyzed and quantified.

RESULTS

ApoE-/- mice fed either SC or CED revealed an increase of alcian blue-positive areas within the media compared to WT mice. PAC1-/-/ApoE-/- mice under CED showed a reduction in the alcian blue-positive plaque area in the BT compared to ApoE-/- mice. In contrast, PACAP deficiency in ApoE-/- mice did not affect the chondrogenic signature under either diet.

CONCLUSIONS

Our data show that PAC1 deficiency reduces chondrogenesis in atherosclerotic plaques exclusively under conditions of CED-induced hypercholesterolemia. We conclude that CED-related chondrogenesis occurs in atherosclerotic plaques via transdifferentiation of SMCs and MΦ, partly depending on PACAP signaling through PAC1. Thus, PAC1 antagonists or PACAP agonists may offer therapeutic potential against pathological chondrogenesis in atherosclerotic lesions generated under hypercholesterolemic conditions, especially in familial hypercholesterolemia. This discovery opens therapeutic perspectives to be used in the treatment against the progression of atherosclerosis.

Deficiency of pituitary adenylate cyclase-activating peptide and its receptor PAC1 confers interstitial cardiac fibrosis in a murine model of metabolic stress

Background

Fibrosis is a hallmark of cardiac remodeling and is present in a variety of cardiac diseases. In particular, in the highly prevalent heterogeneous group of cardiac dysfunctions with preserved left ventricular ejection fraction (LVEF), interstitial fibrosis has been identified as a pivotal pathophysiological factor. Current evidence suggests that comorbidities, mainly from the metabolic spectrum, promote chronic systemic low-grade inflammation with secondary affection of the heart, leading to fibrosis and thus impairing cardiac structure and function. In contrast to cardiac dysfunction with reduced LVEF, which is predominantly of ischemic origin, effective antifibrotic treatment options are very limited emphasizing the urgent need for new therapeutic targets. In this context, the recent report of an antifibrotic effect of the pleiotropic neuropeptide pituitary adenylate cyclase-activating peptide (PACAP) in irradiation-induced myocardial damage [1] renders it an intriguing new candidate.

Purpose

The aim of this study is to elucidate the role of PACAP and of PAC1 receptor in cardiac fibrosis in a murine model of metabolic stress.

Methods

PACAP−/− and PAC1−/− C57/Bl6 J mice were crossbred with an ApoE−/− strain and metabolic stress was induced by feeding a cholesterol-enriched diet (CED) for 10 weeks. Standard chow (SD) served as control diet. Tissue samples of the ventricles were processed for FFPE histological analysis with hematoxylin/eosin, Giemsa and picrosirius red stains and subjected to morphometric quantification of cardiomyocyte cross diameters and fibrosis using a software-based image analysis approach.

Results

After 10 weeks of CED, a statistically significant higher extent of myocardial fibrosis was detected in PACAP−/−/ApoE−/− and PAC1−/−/ApoE−/− compared to ApoE−/− mice (Fig. 1). The pattern of fibrous deposition was consistent with that of reactive interstitial fibrosis and affected both ventricles uniformly. Morphometric analysis revealed no macroscopic or cellular hypertrophy in the PACAP−/−/ApoE−/− and PAC1−/−/ApoE−/− mice compared with ApoE−/− mice after CED. All morphological changes were exclusively present after feeding CED and were not detectable with SD feeding.

Conclusions

This study provides novel evidence for a significant involvement of PACAP and its receptor PAC1 in the development of metabolically induced cardiac fibrosis. The antifibrotic effect of PACAP, which can be inferred in this context, is mediated to a significant extent via the PAC1 receptor, and only becomes apparent under metabolic stress conditions. The absence of macroscopic and cellular cardiac hypertrophy in PACAP deficient or PAC1 deficient mice as demonstrated here precludes relevant hemodynamic effects of PACAP and PAC1 receptor, respectively. According to the results of our pilot study, PACAP analogues or PAC1 receptor agonists may offer a therapeutic potential to attenuate metabolically triggered cardiac fibrosis.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): This research was partly supported by the Von Behring-Röntgen-Stiftung Schloss 1 D-35037 Marburg, Germany.

Characterization of atherosclerotic plaques in blood vessels with low oxygenated blood and blood pressure (Pulmonary trunk): role of growth differentiation factor-15 (GDF-15)

BACKGROUND

Growth differentiation factor (GDF)-15 is linked to inflammation, cancer, and atherosclerosis. GDF-15 is expressed in most tissues but is extremely induced under pathological conditions. Elevated serum levels are suggested as a risk factor and a marker for cardiovascular diseases. However, the cellular sources and the effects of GDF-15 on the cardiovascular system have not been completely elucidated including progression, and morphology of atherosclerotic plaques. Thus, this work aimed to characterize the influence of GDF-15 deficiency on the morphology of atherosclerotic plaques in blood vessels with low-oxygen blood and low blood pressure as the pulmonary trunk (PT), in hypercholesterolemic ApoE-/- mice.

METHODS

GDF-15-/- ApoE-/- mice were generated by crossbreeding of ApoE-/-- and GDF-15-/- mice. After feeding a cholesterol-enriched diet (CED) for 20 weeks, samples of the brachiocephalic trunk (BT) and PT were dissected and lumen stenosis (LS) was measured. Furthermore, changes in the cellularity of the PT, amounts of apoptosis-, autophagy-, inflammation- and proliferation-relevant proteins were immunohisto-morphometrically analyzed. Additionally, we examined an atherosclerotic plaque in a human post mortem sample of the pulmonary artery.

RESULTS

After CED the body weight of GDF-15-/-ApoE-/- was 22.9% higher than ApoE-/-. Double knockout mice showed also an 35.3% increase of plasma triglyceride levels, whereas plasma cholesterol was similar in both genotypes. LS in the BT and PT of GDF-15-/-ApoE-/- mice was significantly reduced by 19.0% and by 6.7% compared to ApoE-/-. Comparing LS in PT and BT of the same genotype revealed a significant 38.8% (ApoE-/-) or 26.4% (GDF-15-/-ApoE-/-) lower LS in the PT. Immunohistomorphometry of atherosclerotic lesions in PT of GDF-15-/-ApoE-/- revealed significantly increased levels (39.8% and 7.3%) of CD68 + macrophages (MΦ) and α-actin + smooth muscle cells than in ApoE-/-. The density of TUNEL + , apoptotic cells was significantly (32.9%) higher in plaques of PT of GDF-15-/-ApoE-/- than in ApoE-/-. Analysis of atherosclerotic lesion of a human pulmonary artery showed sm-α-actin, CD68+, TUNEL+, Ki67+, and APG5L/ATG+ cells as observed in PT. COX-2+ and IL-6+ immunoreactivities were predominantly located in endothelial cells and subendothelial space. In BT and PT of GDF15-/-ApoE-/- mice the necrotic area was 10% and 6.5% lower than in ApoE-/-. In BT and PT of GDF15-/-ApoE-/- we found 40% and 57% less unstable plaques than ApoE-/- mice.

CONCLUSIONS

Atherosclerotic lesions occur in both, BT and PT, however, the size is smaller in PT, possibly due to the effect of the low-oxygen blood and/or lower blood pressure. GDF-15 is involved in atherosclerotic processes in BT and PT, although different mechanisms (e.g. apoptosis) in these two vessels seem to exist.

Effect of cholesterol re-supplementation and atorvastatin on plaque composition in the thoracic aorta of New Zealand white rabbits

BACKGROUND

Effects of re-supplementation of a cholesterol-enriched diet (CEDrs) on size, cholesterol content and morphology of already existing plaques are not known to date.

METHODS

A group of rabbits received standard chow (SC) for 6 weeks ("negative control"; for plasma lipid measurements only). Group I-IV received 2% CED (induction) for 6 weeks; thereafter, groups II-IV have been fed a SC (= cholesterol withdrawal) for 68 weeks. Afterwards, feeding of groups II-IV was continued as follows: Group II - 10 weeks SC, group III - 4 weeks 0.5% CED (~re-supplementation), afterwards 6 weeks SC (~withdrawal again); group IV - 4 weeks 0.5% CED (re-supplementation) + atorvastatin (2.5 mg/kg body weight/day), afterwards 6 weeks SC (~withdrawal again) + atorvastatin. Plasma lipids, but also plaque size, morphology and cholesterol contents of thoracic aortas were quantified.

RESULTS

After CEDrs, plasma cholesterol levels were increased. However, after withdrawal of CEDrs, plasma cholesterol levels decreased, whereas the cholesterol content of the thoracic aorta was increased in comparison with the group without CEDrs. Plaque size remained unaffected. Atorvastatin application did not change plasma cholesterol level, cholesterol content of the thoracic aorta and plaque size in comparison with the group without drug treatment. However, atorvastatin treatment increased the density of macrophages (MΦ) compared with the group without treatment, with a significant correlation between densities of MΦ (Mac-1⁺) and apoptotic (TUNEL⁺; TP53⁺), antigen-presenting (HLA-DR⁺) or oxidatively stressed (SOD2⁺) cells.

CONCLUSIONS

In rabbits with already existing plaques, CEDrs affects plaque morphology and cellular composition, but not plaque size. Despite missing effects on plasma cholesterol levels, cholesterol content of the thoracic aorta and size of already existing atherosclerotic plaques, atorvastatin treatment transforms the already existing lesions to a more active form, which may accelerate the remodelling to a more stable plaque.

Morphological Alterations in Gastrocnemius and Soleus Muscles in Male and Female Mice in a Fibromyalgia Model

BACKGROUND

Fibromyalgia (FM) is a chronic musculoskeletal pain disorder, characterized by chronic widespread pain and bodily tenderness and is often accompanied by affective disturbances, however often with unknown etiology. According to recent reports, physical and psychological stress trigger FM. To develop new treatments for FM, experimental animal models for FM are needed to be development and characterized. Using a mouse model for FM including intermittent cold stress (ICS), we hypothesized that ICS leads to morphological alterations in skeletal muscles in mice.

METHODS

Male and female ICS mice were kept under alternating temperature (4 °C/room temperature [22 °C]); mice constantly kept at room temperature served as control. After scarification, gastrocnemius and soleus muscles were removed and snap-frozen in liquid nitrogen-cooled isopentane or fixed for electron microscopy.

RESULTS

In gastrocnemius/soleus muscles of male ICS mice, we found a 21.6% and 33.2% decrease of fiber cross sectional area (FCSA), which in soleus muscle concerns the loss of type IIa and IIx FCSA. This phenomenon was not seen in muscles of female ICS mice. However, this loss in male ICS mice was associated with an increase in gastrocnemius of the density of MIF+ (8.6%)-, MuRF+ (14.7%)-, Fbxo32+ (17.8%)-cells, a 12.1% loss of capillary contacts/muscle fiber as well as a 30.7% increase of damaged mitochondria in comparison with male control mice. Moreover, significant positive correlations exist among densities (n/mm(2)) of MIF+, MuRF+, Fbxo32+-cells in gastrocnemius/ soleus muscles of male ICS mice; these cell densities inversely correlate with FCSA especially in gastrocnemius muscle of male ICS mice.

CONCLUSION

The ICS-induced decrease of FCSA mainly concerns gastrocnemius muscle of male mice due to an increase of inflammatory and atrogenic cells. In soleus muscle of male ICS and soleus/gastrocnemius muscles of female ICS mice morphological alterations seem to occur not at all or delayed. The sex-specificity of findings, which is not easily reconciled with the epidemiology of FM (female predominance), implicate that gastrocnemius muscle of male ICS mice should preferentially be used for future investigations with FM. Moreover, we suggest to investigate morphological and/or molecular alterations at different time-points (up to two weeks) after ICS.

Cytoprotection by omega-3 fatty acids as a therapeutic drug vehicle when combined with nephrotoxic drugs in an intravenous emulsion: Effects on intraglomerular mesangial cells

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Distinct concentrations of Ketorolac/Gentamicin are toxic to mesangial (MES 13) cells.

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Omega-3 fatty acids protect intraglomerular mesangial cells against nephrotoxic drugs.

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Omega-6 fatty acids do not protect MES 13 cells against nephrotoxic drugs.

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Cytoprotection by n-3 PUFA may be due to increased intracellular redox state.

During therapeutic interventions, blood concentrations of intravenously applied drugs are higher, and their onset of pharmacological action is faster than with other routes of drug administration. However, acute drug therapy often produces nephrotoxic side effects, as commonly seen after treatment with Ketorolac or Gentamicin leading to questions about their use, especially for patients at risk for acute renal failure. Omega-6(n-6) and omega-3(n-3) polyunsaturated fatty acids (PUFA) affect eicosanoid metabolism, which plays a role in the regulation of inflammation. Eicosanoids derived from n-6 FA have proinflammatory and immunoactive functions, whereas eicosanoids derived from n-3 PUFA have anti-inflammatory and cytoprotective properties. We hypothesized that providing such injectable drugs with nephrotoxic potential in combination with n3-PUFAs from the outset, might afford rapid cytoprotection of renal cells, given the recent evidence that intravenously administered n3-PUFAs are rapidly incorporated into cell membranes. We used intraglomerular mesangial cells (MES13) that are sensitive to treatment with Ketorolac or Gentamicin instead of proximal tubular cells which do not respond to Ketorolac. We found a significant inhibition of Ketorolac (0.25, 0.5, 1 mM) or Gentamicin (2.5, 5 mM) induced cytotoxicity after pretreatment of MES13 cells with 0.01% of 20%w/v LipOmega-3 Emulsion 9/1, containing 90:10 wt/wt mixture of fish oil derived triglycerides to medium chain triglycerides.

Evaluation of the effects of different culture media on the myogenic differentiation potential of adipose tissue- or bone marrow-derived human mesenchymal stem cells

The creation of functional muscles/muscle tissue from human stem cells is a major goal of skeletal muscle tissue engineering. Mesenchymal stem cells (MSCs) from fat/adipose tissue (AT-MSCs), as well as bone marrow (BM-MSCs) have been shown to bear myogenic potential, which makes them candidate stem cells for skeletal muscle tissue engineering applications. The aim of this study was to analyse the myogenic differentiation potential of human AT-MSCs and BM-MSCs cultured in six different cell culture media containing different mixtures of growth factors. The following cell culture media were used in our experiments: mesenchymal stem cell growth medium (MSCGM)™ as growth medium, MSCGM + 5-azacytidine (5-Aza), skeletal muscle myoblast cell growth medium (SkGM)-2 BulletKit™, and 5, 30 and 50% conditioned cell culture media, i.e., supernatant of human satellite cell cultures after three days in cell culture mixed with MSCGM. Following the incubation of human AT-MSCs or BM-MSCs for 0, 4, 8, 11, 16 or 21 days with each of the cell culture media, cell proliferation was measured using the alamarBlue® assay. Myogenic differentiation was evaluated by quantitative gene expression analyses, using quantitative RT-PCR (qRT-PCR) and immunocytochemical staining (ICC), using well-defined skeletal markers, such as desmin (DES), myogenic factor 5 (MYF5), myosin, heavy chain 8, skeletal muscle, perinatal (MYH8), myosin, heavy chain 1, skeletal muscle, adult (MYH1) and skeletal muscle actin-α1 (ACTA1). The highest proliferation rates were observed in the AT-MSCs and BM-MSCs cultured with SkGM-2 BulletKit medium. The average proliferation rate was higher in the AT-MSCs than in the BM-MSCs, taking all six culture media into account. qRT-PCR revealed the expression levels of the myogenic markers, ACTA1, MYH1 and MYH8, in the AT-MSC cell cultures, but not in the BM-MSC cultures. The muscle-specific intermediate filament, DES, was only detected (by ICC) in the AT-MSCs, but not in the BM-MSCs. The strongest DES expression was observed using the 30% conditioned cell culture medium. The detection of myogenic markers using different cell culture media as stimuli was only achieved in the AT-MSCs, but not in the BM-MSCs. The strongest myogenic differentiation, in terms of the markers examined, was induced by the 30% conditioned cell culture medium.

Mechanisms of the anti-proliferative and anti-inflammatory effects of the herbal fixed combination STW 5 (Iberogast®) on colon adenocarcinoma (HT29) cells in vitro

INTRODUCTION

Several conventional pharmaceuticals like non-steroidal anti-inflammatory drugs (NSAIDS) or selective cyclooxygenase-2 (COX-2) inhibitors have been demonstrated to exert anti-proliferative effects and to induce apoptosis in a variety of cell lines, e.g. colon, stomach, or prostate cancer cells. STW 5 (Iberogast(®)), a combination of nine plant extracts, is widely used in the treatment of gastrointestinal disorders, including functional dyspepsia and irritable bowel syndrome for which the involvement of an inflammatory etiology is discussed. To investigate the possible anti-proliferative effects, STW 5 and its components have been tested by using the colon-carcinoma cell line HT-29. The analyses have been performed in comparison to acetylsalicylic acid (ASA) and diclofenac (Diclo), which are well-known to reduce colon carcinoma risk.

RESULTS

STW 5 showed significant anti-proliferative and pro-apoptotic effects on HT-29 cancer cells, similar to NSAIDs under test. However, using the LDH assay, STW 5 revealed significantly lower cytotoxicity than Diclo at same concentrations. In contrast to NSAIDs, STW 5 induced COX-1/COX-2, caspase-3 and Bax mRNA expressions in HT-29 and blocked LPS mediated translocation of the NF-κB p65 from the cytoplasm into the nucleus in PMA-differentiated THP-1 macrophages. These effects might be relevant, e.g. for prevention of undesirable side effects like gastric erosions.

CONCLUSION

Our data suggest that the pro-apoptotic effect of STW 5 on HT-29 cells is involving multiple targets and is possibly due to an activation of the caspase cascade via mitochondrial destabilization. Active concentrations of STW 5 are, in relation to therapeutic doses, comparable to those of ASA and Diclo, suggesting a similar favorable effect on colon carcinoma risk.

Impact of static magnetic fields on human myoblast cell cultures

Treatment of skeletal muscle loss due to trauma or tumor ablation therapy still lacks a suitable clinical approach. Creation of functional muscle tissue in vitro using the differentiation potential of human satellite cells (myoblasts) is a promising new research field called tissue engineering. Strong differentiation stimuli, which can induce formation of myofibers after cell expansion, have to be identified and evaluated in order to create sufficient amounts of neo-tissue. The objective of this study was to determine the influence of static magnetic fields (SMF) on human satellite cell cultures as one of the preferred stem cell sources in skeletal muscle tissue engineering. Experiments were performed using human satellite cells with and without SMF stimulation after incubation with a culture medium containing low [differentiation medium (DM)] or high [growth medium (GM)] concentrations of growth factors. Proliferation analysis using the alamarBlue assay revealed no significant influence of SMF on cell division. Real-time RT-PCR of the following marker genes was investigated: myogenic factor 5 (MYF5), myogenic differentiation antigen 1 (MYOD1), myogenin (MYOG), skeletal muscle α1 actin (ACTA1), and embryonic (MYH3), perinatal (MYH8) and adult (MYH1) skeletal muscle myosin heavy chain. We detected an influence on marker gene expression by SMF in terms of a down-regulation of the marker genes in cell cultures treated with SMF and DM, but not in cell cultures treated with SMF and GM. Immunocytochemical investigations using antibodies directed against the differentiation markers confirmed the gene expression results and showed an enhancement of maturation after stimulation with GM and SMF. Additional calculation of the fusion index also revealed an increase in myotube formation in cell cultures treated with SMF and GM. Our findings show that the effect of SMF on the process of differentiation depends on the growth factor concentration in the culture medium in human satellite cultures. SMF alone enhances the maturation of human satellite cells treated with GM, but not satellite cells that were additionally stimulated with serum cessation. Therefore, further investigations are necessary before consideration of SMF for skeletal muscle tissue engineering approaches.

Characterization of human myoblast differentiation for tissue-engineering purposes by quantitative gene expression analysis

Tissue engineering of skeletal muscle is an encouraging possibility for the treatment of muscle loss through the creation of functional muscle tissue in vitro from human stem cells. Currently, the preferred stem cells are primary, non-immunogenic satellite cells ( = myoblasts). The objective of this study was to determine the expression patterns of myogenic markers within the human satellite cell population during their differentiation into multinucleated myotubes for an accurate characterization of stem cell behaviour. Satellite cells were incubated (for 1, 4, 8, 12 or 16 days) with a culture medium containing either a low [ = differentiation medium (DM)] or high [ = growth medium (GM)] concentration of growth factors. Furthermore, we performed a quantitative gene expression analysis of well-defined differentiation makers: myogenic factor 5 (MYF5), myogenin (MYOG), skeletal muscle αactin1 (ACTA1), embryonic (MYH3), perinatal (MYH8) and adult skeletal muscle myosin heavy chain (MYH1). Additionally, the fusion indices of forming myotubes of MYH1, MYH8 and ACTA1 were calculated. We show that satellite cells incubated with DM expressed multiple characteriztic features of mature skeletal muscles, verified by time-dependent upregulation of MYOG, MYH1, MYH3, MYH8 and ACTA1. However, satellite cells incubated with GM did not reveal all morphological aspects of muscle differentiation. Immunocytochemical investigations with antibodies directed against the differentiation markers showed correlations between the gene expression and differentiation. Our data provide information about time-dependent gene expression of differentiation markers in human satellite cells, which can be used for maturation analyses in skeletal muscle tissue-engineering applications.

Anti-inflammatory effects of the willow bark extract STW 33-I (Proaktiv(®)) in LPS-activated human monocytes and differentiated macrophages

INTRODUCTION

Willow bark extract is frequently used in the treatment of painful rheumatological diseases, such as arthritis and back pain. Its effect has been attributed to its main component salicin, but pharmacological studies have shown that the clinical efficacy of the willow bark extract cannot be explained by its salicin content alone. Therefore different modes of action have been suggested for the anti-inflammatory effect of willow bark extract. Here, we report in vitro data revelling the effect and mode of action of the aqueous willow bark extract STW 33-I as well as a water-soluble fraction (fraction E [Fr E]) in comparison with well-known non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin (ASA) and diclofenac (Diclo) on pro-inflammatorily activated human monocytes and differentiated macrophages.

RESULTS

STW 33-I and the water-soluble Fr E showed concentration-dependent and significant anti-inflammatory effects in lipopolysaccharide-activated monocytes. Both inhibited the intracellular protein expression of tumour necrosis factor-alpha (TNFα) as well as the mRNA expression of TNFα and cyclooxygenase 2 (COX-2), and the release of nitric oxide (NO). In addition, apoptosis of pro-inflammatorily activated monocytes was induced. Furthermore, treatment of activated macrophages with STW 33-I inhibited the nuclear translocation of the p65 subunit of the nuclear transcription factor-kappa B (NF-κB p65).

CONCLUSIONS

The present in vitro investigations suggest a significant anti-inflammatory activity of willow bark water extract STW 33-1 and of its water-soluble fraction by inhibiting pro-inflammatory cytokines (TNFα), COX-2 and nuclear translocation of the transcription factor NF-κB in pro-inflammatorily activated monocytes. Our results provide further evidence for the therapeutic use of STW 33-I in inflammation-related disorders.

In vitro anti-proliferative effects of the willow bark extract STW 33-I

The well-known anti-inflammatory and analgesic effects of the phytopharmacon willow bark extract have been attributed to the content of salicin; however, pharmacological studies have shown that salicin alone, despite being involved in its therapeutic action, cannot fully explain its clinical efficacy. In addition to reducing inflammation and pain, acetylsalicylic acid (ASA, CAS 50-78-2), like other synthetic non-steroidal anti-inflammatory drugs (NSAIDs), has been shown to exert anti-proliferative effects and to induce apoptosis in a variety of cell lines, e.g., colon, stomach, and prostate cancer cells. To investigate the mechanism of action and possible anti-proliferative and proapoptotic effects of willow bark, a water extract (STW 33-I) and a polyphenol rich fraction (fraction E) have been tested by using the colon-carcinoma cell line HT-29. Both, STW 33-I and its fraction E showed significant anti-proliferative and (1) Introduction The most well-known component of willow bark extract is salicin, which is metabolized in vivo to salicylic acid. The standardized aqueous willow bark extract STW 33-I, which is an effective analgesic and anti-inflammatory drug, contains 23-26% total salicin derivatives and additionally flavonoids, condensed tannins and polyphenols. Typical representatives of the flavonoids are glycosides of naringenin, isosalipurpuroside or eriodictyol. In vitro experiments have demonstrated for pro-apoptotic effects on HT-29 cancer cells. Related to the salicin content of the willow bark extract, a higher dosage of ASA was needed. Furthermore, compared to ASA and to diclofenac (Diclo, CAS 15307-79-6), the COX-1 and COX-2 mRNA expressions were influenced differently by STW 33-I and fraction E. ASA and Diclo inhibited both the COX-1 and COX-2 mRNA expressions, whereas STW 33-I and its fraction E increased the COX-1 mRNA expression. In addition to the already well-known anti-inflammatory and analgesic effects, willow bark extract has been found to possess anti-proliferative and pro-apoptotic effects similar to NSAIDs. The different influence of willow bark on the COX-1 and COX-2 mRNA expressions in comparison to NSAIDs might be relevant, e.g., for prevention of undesirable side effects such as gastric erosions.

Expression of growth differentiation factor-15/ macrophage inhibitory cytokine-1 (GDF-15/MIC-1) in the perinatal, adult, and injured rat brain

We and others have recently cloned a new member of the transforming growth factor-beta superfamily, growth differentiation factor-15/ macrophage inhibitory cytokine-1 (GDF-15/MIC-1). Using in situ hybridization and immunohistochemistry, we determined the distribution of GDF-15/MIC-1 mRNA and protein in the perinatal and cryolesioned adult rat brain. The choroid plexus epithelium of all ventricles represents the site of strongest and almost exclusive mRNA expression in the normal perinatal and adult brain. The newborn rat brain reveals GDF-15/MIC-1 immunoreactivity (ir) in ependymal cells lining the ventricles, in the striatal subventricular zone, and in populations of nonneural cells of the thalamic/hippocampal lamina affixa, in addition to that in the choroid plexus. Unilateral cryogenic cortical lesioning induced a significant increase of GDF-15/MIC-1 mRNA expression and ir at the lesion site and expression in presumed neurons within the dorsal thalamic area. At the lesion site, GDF-15/MIC-1-producing cells showed immuncytochemical features of neurons, macrophages, and activated microglial cells. Fluorescent microscopy revealed both intra- and extracellular GDF-15/MIC-1 ir. Up-regulation of GDF-15/MIC-1 in activated macrophages (Mstraight phi) is also supported by RT-PCR, ICC, and Western blot experiments showing pronounced induction of GDF-15/MIC-1 expression (mRNA and protein) in retinoic acid/phorbol ester-stimulated human M phi. Our data suggest that 1) GDF-15/MIC-1 is secreted into the cerebrospinal fluid and 2) in the newborn brain may penetrate through the ependymal lining and act on developing neurons and/or glial cells. As a constituent of cells in the lamina affixa, the protein might be involved in the regulation of mesenchyme-epithelial interactions. Finally, GDF-15/MIC-1 may also act within the antiinflammatory cytokine network activated in CNS lesions.

Ceramide induces aSMase expression: implications for oxLDL-induced apoptosis

Sphingomyelinase (SMase) stimulation and subsequent ceramide generation are suggested to be involved in signal transduction of stress-induced apoptosis. We now show that apoptosis of human macrophages (MPhi) and fibroblasts initiated by oxidized low density lipoproteins (minimally modified LDL, mmLDL) is associated with an increase in acid SMase (aSMase, E.C. 3.1.4.12) expression and ceramide concentration. Application of a novel, potent, and specific inhibitor of aSMase expression (NB6) diminished the effects of mmLDL and C6-ceramide treatment by inhibiting transcription via Sp1 and AP-2. Moreover, apoptosis was abolished after mmLDL and C6-ceramide treatment of hereditary aSMase-deficient fibroblasts (from Niemann-Pick patients). We suggest that in mmLDL-initiated apoptosis 1) enhanced ceramide generation via aSMase appears to be required as well as 2) a positive feedback control of aSMase expression by the increase in intracellular ceramide concentration.

Characterization of apoptotic macrophages in atheromatous tissue of humans and heritable hyperlipidemic rabbits

Apoptotic macrophages are regularly found in atherosclerotic plaques indicating programmed cell death as one of their regulatory controls. The objective of this study was to characterize in more detail apoptotic macrophages in atherosclerotic lesions of humans and heritable hyperlipidemic (HHL) rabbits. Macrophages were immunohistochemically analyzed using antibodies directed against alphaMbeta2-integrins (CD11b/CD18), CD44, major histocompatibility complex (MHC) class I and II, inducible nitric oxide synthase (iNOS), manganese superoxide dismutase (MnSOD), tumor necrosis factor alpha (TNFalpha), p53, c-jun/AP-1 and rabbit macrophages (RAM-11) and the TUNEL (TdT-mediated dUTP nick end labeling) technique. Colocalization studies of human atherosclerotic carotid and aortic tissue showed apoptotic plaque macrophages also being MnSOD-, alphaMbeta2-integrin-, CD44-, MHC class I- and II-, iNOS-, TNFalpha- and p53-immunoreactive. Similar results occurred in atherosclerotic aortas of HHL rabbits. Computer-assisted morphometric analyses revealed a positive correlation of the area density of MnSOD-immunoreactive macrophages with those of alphaMbeta2-integrin- and CD44-immunoreactive ones, but not with those of MHC class I- and II- as well as of RAM-11-immunoreactive macrophages. We conclude that apoptotic macrophages located in atherosclerotic vessel wall are activated, antigen-presenting, integrin-expressing and oxidatively stressed cells. Since all these processes have been demonstrated to cause apoptosis of macrophages in vitro, we propose their potency accelerates the susceptibility of the macrophages to programmed cell death in atherosclerotic lesions.

Isolation of a frog lectin using polylysine to reduce non-specific interactions with heparin binding ligand

Polylysine is a polycation used in histology to glue tissue sections to glass slides. It was successfully used to eliminate positively charged proteins from heparin-agarose beds applied for affinity chromatography facilitating the preparative steps in the isolation and purification of heparin binding lectins from the ovary of the frog Leptodactylus occellatus. The addition pretreatment of agarose-heparin beds with polylysine increased more than 3-fold the hemagglutinating capacity of eluted lectin.