Effect of stem cell secretome in skin rejuvenation: a narrative review

PURPOSE

Cutaneous aging is an inevitable biological process that develops over time due to cumulative cellular and molecular changes caused by exposure to intrinsic (chronological aging) and extrinsic (photo-aging) factors on the skin. Skin aging is characterized by a decline in the body's capability to sustain senescence, dermal cell apoptosis, and homeostasis. Stem cell secretions (secretome) are defined as the total set of dynamically overlapping paracrine soluble growth factors, cytokines, chemokines, angiogenic factors, extracellular matrix proteins, and antimicrobial peptides known to be responsible for tissue rejuvenation, regeneration, homeostasis, and immunomodulation.

METHODS

In this review, we summarized the molecular and regulatory mechanism of the secretome in preventing the skin aging process, as well as its capacity in inducing skin rejuvenation. Furthermore, we illustrated secretome efficiency as an anti-aging therapeutic strategy based on in vitro and in vivo published studies.

RESULTS

In all reviewed publications, the secretome has been proven to be the most effective treatment for aged skin, capable of reversing the aging process through the action of cytokines, growth factors, and collagen, which are its primary components. The reported mechanism of action involves modulating the signaling pathways of aging and replenishing the skin with collagen, fibronectin, and elastin, ultimately resulting in skin renewal and rejuvenation.

CONCLUSION

In conclusion, compared to available treatments, the secretome shows great promise as an anti-aging therapy.

Stem cell secretome as a mechanism for restoring hair loss due to stress, particularly alopecia areata: narrative review

Background

Living organisms are continuously exposed to multiple internal and external stimuli which may influence their emotional, psychological, and physical behaviors. Stress can modify brain structures, reduces functional memory and results in many diseases such as skin disorders like acne, psoriasis, telogen effluvium, and alopecia areata. In this review, we aim to discuss the effect of secretome on treating alopecia, especially alopecia areata. We will shed the light on the mechanism of action of the secretome in the recovery of hair loss and this by reviewing all reported in vitro and in vivo literature.

Main body

Hair loss has been widely known to be enhanced by stressful events. Alopecia areata is one of the skin disorders which can be highly induced by neurogenic stress especially if the patient has a predisposed genetic background. This condition is an autoimmune disease where stress in this case activates the immune response to attack the body itself leading to hair cycle destruction. The currently available treatments include medicines, laser therapy, phototherapy, and alternative medicine therapies with little or no satisfactory results. Regenerative medicine is a new era in medicine showing promising results in treating many medical conditions including Alopecia. The therapeutic effects of stem cells are due to their paracrine and trophic effects which are due to their secretions (secretome).

Conclusion

Stem cells should be more used as an alternative to conventional  therapies due to their positive outcomes. More clinical trials on humans should be done to maximize the dose needed and type of stem cells that must be used to treat alopecia areata.

Mesenchymal Stem Cell Exosomes and Cancer: Controversies and Prospects

Mesenchymal stem cells (MSCs) have displayed a novel therapeutic strategy for a wide range of diseases and conditions. Their secretome and exosome-based paracrine activity are considered as the main processes harboring their diverse therapeutic properties. Several investigations have examined the effects of MSC-derived exosomes on cancer growth, yet, controversial results have always emerged. Although MSC-derived exosomes are able to rigorously enforce the repression of cancer proliferation and progression, it is shown that MSCs exosomal activity displays numerous protumorigenic effects. This discrepancy over the dual effects of MSCs on cancer growth may be mediated by many factors including experimental design, stem cells origins, culture conditions, in addition to cancer-MSCs cross-talks. Despite the controversial effects of MSCs on carcinogenesis, scientists are able to overcome a number of obstacles by modifying MSCs to deliver antioncogenic miRNAs, anticancer drugs, and oncolytic viruses into tumor sites. This review discusses the controversial effects of MSC-derived exosomes on tumorigenesis, investigates the main causes that underlie this discrepancy, summarizes the pattern of engineered-MSCs, and finally highlights how future studies should advance the research in the field of MSCs-based cancer therapies in order to accelerate the transition from preclinical studies to clinical practice.

Craniofacial and traumatic brain injuries in mixed martial arts

Objective: Mixed-Martial-Arts (MMA) has witnessed a rapid growth over the recent years. This study aims to explore the patterns and trends of head injuries in MMA.Design: Descriptive epidemiological study.Setting: Ringside physician reports of the Ultimate Fighting Championship (UFC) fights between 2016 and 2019 (inclusive) were screened. Data were extracted from the Nevada State Athletic Commission (NSAC) database. Play-by-play video analysis was also conducted.Participants: UFC fighters involved in fights sanctioned by the NSAC, between 2016 and the end of 2019 (N = 816).Independent variables: Sex, location of head injury, type of head injury, injury mechanism, number of significant head strikes, type of finish, and weight division.Main outcome measures: Head injury rates were calculated. A one-way analysis of variance (ANOVA) was used to explore any statistically significant differences between injury rates of different locations, types, and types of finishes. An independent t-test was used to determine whether any significant differences existed between the two sexes, and a Joinpoint regression analysis was used to determine the statistical significance of the trends of head injury rates across different weight divisions. P-values <0.05 were considered significant (95% CI).Results: A total of 288 head injuries in 408 fights were recorded during our study period. Head injury rate constituted 35 injuries per 100 athletic-exposures (AE) in sanctioned fights. Traumatic brain injuries (TBI) were the most common type of injury, with a rate of 16 per 100AE, significantly greater than that of fractures (p = 0.003). Males had a head injury rate of 37 per 100AE, higher than that of females which was 23 per 100AE. Technical Knockout (TKO)/ Knockout(KO) was the type of finish with the highest rate of head injuries, significantly greater than that of decision or submission (p < 0.001). In general, head injury rates were higher as weight divisions increased.Conclusion: Head injuries are prevalent in MMA. Preventive measures need to be implemented to ensure fighter safety and limit injury risk.

Realizing the Potential of Blueberry as Natural Inhibitor of Metastasis and Powerful Apoptosis Inducer: Tapping the Treasure Trove for Effective Regulation of Cell Signaling Pathways

Blueberries belong to the genus Vaccinium of the family Ericaceae. Rapidly accumulating experimentally verified data is uncovering the tremendous pharmacological properties of biologically active constituents of blueberries against different diseases. Our rapidly evolving knowledge about the multifaceted nature of cancer has opened new horizons to search for different strategies to target multiple effectors of oncogenic networks to effectively inhibit cancer onset and progression. Excitingly, whole blueberry powder and various bioactive constituents (pterostilbene, malvidin-3-galactoside) of blueberries have been shown to efficiently inhibit metastasis in animal models. These results are encouraging and future studies must focus on the identification of cell signaling pathways effectively modulated by blueberries in different cancers. It seems exciting to note that researchers are focusing on metastasis inhibitory effects of blueberry; however, to reap full benefits, it is necessary to take a step back and critically re-interpret the mechanisms used by active components of blueberry to inhibit or prevent metastasis. JAK/STAT, TGF/SMAD, Notch, SHH/GLI, and Wnt/ β-Catenin have been shown to be directly involved in the regulation of metastasis. However, because of limited studies, it is difficult to critically assess the true potential of blueberry. Loss of apoptosis, metastasis and deregulation of signaling pathways are branching trajectories of molecular oncology. Accordingly, we have to emphasize on these essential facets to realistically claim blueberry as "Superfood". Different clinical trials have been conducted to gather clinical evidence about the chemopreventive role of blueberry or its bioactive components in cancer patients. But it seems clear that because of the lack of sufficient proof-of-concept studies, we cannot extract significant information about the transition of blueberry into the next phases of clinical trials. Overview of the existing scientific evidence revealed visible knowledge gaps and a better understanding of the targets of blueberry will be helpful in efficient and meaningful translation of laboratory findings to clinically effective therapeutics.

Mesenchymal Stromal Cell Secretome: Immunomodulation, Tissue Repair and Effects on Neurodegenerative Conditions

Mesenchymal stromal cells (MSCs) have emerged as a modern development in therapeutics for a wide variety of diseases. Secreted paracrine factors constitute the principal components harboring the restorative promise of MSCs. Recent studies demonstrate that MSC-derived secretomes are composed of several molecules targeting a variety of biological processes that impact tissue repair, growth and immunomodulation. Indeed, secretomes interact with immune cells, activating regulatory anti-inflammatory phenotypes. In this review, we discuss the action of MSC-derived secretomes in promoting tissue regeneration, opposing the inflammatory response in context-specific cases, and treating neurodegenerative diseases, resulting from chronic neuroinflammation.

Improvement of Human Sperm Vacuolization and DNA Fragmentation Co-Cultured with Adipose-Derived Mesenchymal Stem Cell Secretome: In Vitro Effect

Background and Objectives

Oxidative stress (OS) is known to be an important factor of male infertility. Adipose-derived mesenchymal stem cells (AD-MSCs) are known to have immune-modulatory and anti-oxidant effects through their secretions, hence raising the idea of their potential benefit to improve sperm parameters. This study aims at investigating the effect of AD-MSCs conditioned medium (CM) on human sperm parameters in the presence and absence of H₂O₂-induced OS.

Methods and Results

Sperm samples were collected from 30 healthy men and divided into two groups: non-stressed and H₂O₂-stressed. Isolated AD-MSCs from healthy donors undergoing liposuction were cultured and CM was collected at 24, 48 and 72 h. Both sperm groups were cultured with CM and a time course was performed followed by an evaluation of sperm parameters. The incubation of non-stressed and stressed sperm samples with AD-MSCs-CM for 24 h was found to have the optimum impact on sperm vacuolization, DNA fragmentation and OS levels in comparison to other incubation timings, while preserving motility, viability and morphology of cells. Incubation with CM improved all sperm parameters except morphology in comparison to the non-treated group, with the best effect noted with CM collected at 24 h rather than 48 or 72 h for sperm vacuolization and DNA fragmentation. When compared to fresh semen parameters (T0), samples cultured with CM 24 h showed a significant decrease in sperm vacuolization and DNA fragmentation while keeping other parameters stable.

Conclusions

AD-MSCSs-CM improves sperm quality, and hence can be used in treating infertility and subsequently enhancing IVF outcomes.

MicroRNA-143 as a new weapon against cancer: overview of the mechanistic insights and long non-coding RNA mediated regulation of miRNA-143 in different cancers

Central dogma of molecular biology, a term coined by Francis Crick in 1958 was considered to be the cornerstone of molecular biology unless molecular biologists challenged the idea after ground-breaking discovery of non-coding RNAs. Discovery of microRNAs marked a new era and revolutionized our understanding related to puzzling mysteries about intermediate steps between transcription and translation. Technological advancements have spawned a multitude of platforms for profiling of long-noncoding RNAs and miRNAs in different cancers. Detailed investigation of mRNA targets of miRNAs has enabled high-order analyses of interconnected networks and revealed affected pathways in different cancers. miR-143 has emerged as a multi-talented tumor suppressor microRNA having considerable ability to inhibit and prevent cancer via regulation of myriad of oncogenes. In this review, we will summarize most recent evidence related to characteristically unique ability of miR-143 to target different oncogenic mRNAs in different cancers. We will also comprehensively discuss how scientists have identified multiple long non-coding RNAs reportedly involved in promoting the expression of oncogenes by interfering with miR-143 mediated targeting of these oncogenes. Because of excellent ability of miR-143 to effectively target oncogenic mRNAs, researchers have started to focus on use of miR-143 mimics to restore expression of miR-143 in various cancers.

Anti-proliferative effects of mesenchymal stem cells (MSCs) derived from multiple sources on ovarian cancer cell lines: an in-vitro experimental study

Mesenchymal stem cells (MSCs) have surfaced as ideal candidates for treatment of different therapeutically challenging diseases however their effect on cancer cells is not well determined. In this study, we investigated the effect of MSCs derived from human bone marrow (BM), adipose tissue (AT), and umbilical cord derived MSCs (UC-MSCs) on ovarian cancer.Measurements of ovarian tumor marker proteins were computed by ELISA. Proliferative, apoptosis and anti-inflammatory effects of the MSCs were measured by Flow cytometry (FCM). MMPs expression was measured by RT-PCR.The co-culture of cancer cell lines OVCAR3, CAOV3, IGROV3 and SKOV3 with the conditioned media of MSCs (CM-MSC) and MSCs showed an increase in cellular apoptosis, along with a reduction in the level of CA-125 and a decline of LDH and beta-hCG. A decrease in CD24 of the cancer cell lines in co-culture with the CM-MSCs showed a reduction of the cancer tumorigenicity. In addition, the invasion and aggressiveness of cancer cell lines was significantly decreased by CM-MSC; this was translated by a decrease in MMP-2, MMP-9, and CA-125 mRNA expression, and an increase in TIMP 1, 2, and 3 mRNA expression. An increase in IL-4 and IL-10 cytokines, and a decrease in GM-CSF, IL-6, and IL-9, were also noted.In conclusion, mesenchymal stem cells derived from different sources and their conditioned media appear to have a major role in inhibition of cancer aggressiveness and might be considered as a potential therapeutic tool in ovarian cancer.

Rheumatoid Synovial Fluids Regulate the Immunomodulatory Potential of Adipose-Derived Mesenchymal Stem Cells Through a TNF/NF-κB-Dependent Mechanism

Introduction: Adipose-derived mesenchymal stem cells (ADSC) have been shown to have remarkable immune-modulating effects. However, their efficacy in clinical trials has yet to be fully demonstrated. This could be due to a lack of a proper inflammatory environment in vivo that primes ADSC. Here, we define how the articular microenvironment of rheumatoid arthritis (RA) patients modulates the therapeutic efficiency of ADSC. Methods: Synovial fluids (SF) were collected from 8 RA patients, 2 Spondyloarthritis patients and one control synovial fluid from a patient undergoing traumatic-related surgery. SF inflammatory status was determined by routine analysis and quantification of pro-inflammatory cytokines. ADSC were first treated with SF and ADSC proliferation and gene expression of immunomodulatory factors was evaluated. In order to determine the mechanisms underlying the effect of SF on ADSC, tumor necrosis factor (TNF), interleukin-6 (IL-6), and NF-κB neutralization assays were performed. To evaluate the effect of SF on ADSC functions, ADSC were pre-treated with SF and then co-cultured with either macrophages or T cells. The modulation of their phenotype was assessed by flow cytometry. Results: Pro-inflammatory RASF maintained the proliferative capacity of ADSC and upregulated the gene expression of cyclooxygenase-2 (COX2), indoleamine-1,2-dioxygenase (IDO), interleukin-6 (IL-6), tumor-necrosis factor stimulated gene 6 (TSG6), intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and programmed death-ligand 1 (PD-L1), all factors involved in ADSC immunomodulatory potential. The RASF-induced gene expression was mainly mediated by TNF alone or in combination with IL-6 and signaled through the NF-κB pathway. Conditioning ADSC with pro-inflammatory RASF enhanced their ability to induce CD4⁺Foxp3⁺CD25^high regulatory T cells (Tregs) and inhibit pro-inflammatory markers CD40 and CD80 in activated macrophages. Conclusions: Inflammatory synovial fluids from RA patients had the capacity to modulate ADSC response, to induce Tregs and modulate the phenotype of macrophages. The clinical use of ADSC in affected joints should take into account the influence of the local articular environment on their potential. Having a sufficient pro-inflammatory microenvironment will determine whether optimal immunoregulatory response should be expected. Direct ADSC intra-articular delivery to patients could be a potential strategy to properly prime their immunomodulatory potential and enhance their clinical benefits.

Effect of adipose-derived mesenchymal stem cells on hepatocellular carcinoma: In vitro inhibition of carcinogenesis

AIM

To investigate the effect of adipose-derived mesenchymal stem cells (ADMSCs) and their conditioned media (CM) on hepatocellular carcinoma (HCC) cell tumorigenesis.

METHODS

The proliferation rate of HepG2 and PLC-PRF-5 HCC cancer cells was measured using the trypan blue exclusion method and confirmed using the cell-counting kit 8 (commonly known as CCK-8) assay. Apoptosis was detected by flow cytometry using annexin V-FITC. Protein and mRNA expression was quantified by ELISA and real time PCR, respectively. Migration and invasion rates were performed by Transwell migration and invasion assays. Wound healing was examined to confirm the data obtained from the migration assays.

RESULTS

Our data demonstrated that when co-culturing HCC cell lines with ADMSCs or treating them with ADMSC CM, the HCC cell proliferation rate was significantly inhibited and the apoptosis rate increased. The decreased proliferation rate was accompanied by an upregulation of P53 and Retinoblastoma mRNA and a downregulation of c-Myc and hTERT mRNA levels. More notably, ADMSCs and their CM suppressed the expression of the two important markers of HCC carcinogenicity, alpha-fetoprotein and Des-gamma-carboxyprothrombin. In addition, the migration and invasion levels of HepG2 and PLC-PRF-5 cells significantly decreased, potentially through increased expression of the tissue inhibitor metalloproteinases TIMP-1, TIMP-2 and TIMP-3.

CONCLUSION

These findings shed new light on a protective and therapeutic role for ADMSCs and their CM in controlling HCC invasiveness and carcinogenesis.

Interplay of long non-coding RNAs and TGF/SMAD signaling in different cancers

Based on the exciting insights gleaned from decades of ground-breaking research, it has become evident that deregulated signaling pathways play instrumental role in cancer development and progression. Interestingly discovery of non-coding RNAs has revolutionized our understanding related to transcription, post-transcription and translation. Modern era has witnessed landmark discoveries in the field of molecular cancer and non-coding RNA biology has undergone tremendous broadening. There has been an exponential growth in the list of publications related to non-coding RNAs and overwhelmingly increasing classes of non-coding RNAs are adding new layers of complexity to already complicated nature of cancer. Regulation of TGF/SMAD signaling by miRNAs and LncRNAs has opened new horizons for therapeutic targeting of TGF/SMAD pathway. In this review we have set spotlight on central role of LncRNAs in modulation of TGF/SMAD pathway. Major proportion of the available evidence is underlining positive role of LncRNAs in contextual regulation of TGF/SMAD pathway. LncRNAs are vital to these regulatory networks because they provide a background support to make the TGF/SMAD mediated intracellular signaling more smooth or make transduction cascade more flexible in response to cues from extracellular environment. Therefore, in accordance with this notion, MALAT1, OIP5-AS1, MIR100HG, HOTAIR, ANRIL, PVT1, AFAP1-AS1, SPRY4-IT, ZEB2NAT, TUG1 and Lnc-SNHG1 have been reported to positively regulate TGF/SMAD signaling. In this review, we have focused on the regulation of TGF/SMAD signaling by LncRNAs and how these non-coding RNAs can be therapeutically exploited. Short-interfering RNA (siRNA) and natural products are currently being tested for efficacy against different LncRNAs. Nanotechnological strategies to efficiently deliver LncRNA-targeting siRNAs are also currently being investigated in different cancers.

Different TP53 mutants in p53 overexpressed epithelial ovarian carcinoma can be associated both with altered and unaltered glycolytic and apoptotic profiles

Background

p53 is a tumor suppressor and key regulator of glycolysis in cancer cells, however highly mutated in tumors. In ovarian cancer, studies concerning p53 mutations focus on the DNA binding domain since the majority of hotspot mutations affects this region. Yet, mutations in other regions such as the proline rich domain may also affect the protein’s expression and activity. The aim of this study is to investigate the effect of various positions of mutations in TP53 gene on glycolysis, apoptosis and transcription of p53 target genes.

Methods

Mutations frequency and their effect on p53 expression were assessed by PCR-SSCP, sequencing and immunohistochemistry on 30 ovarian cancer biopsies. Six tumors were cultured, as well as SK-OV-3, OVCAR-3 and Igrov-1. SK-OV-3 cells were transfected with 2 TP53 mutants. p53 transcriptional activity was assayed by qPCR, apoptosis by flow cytometry and glycolysis by glucose and lactate measurements, with quantification of glycolytic enzymes expression.

Results

Our results showed a high frequency of the P72R mutant, associated with p53 overexpression in the ovarian biopsies. However, P72R mutant cells showed similar apoptosis and glycolysis as WT cells. DNA binding domain mutations decreased the transcriptional activity of the protein and increased glucose consumption and lactate production.

Conclusion

Despite the overexpression of the P72R mutated protein in the biopsies, it showed a similar apoptotic activity and glucose regulation ability as WT p53. Knowing that p53 expression status is used for chemotherapeutic approaches and prognosis in ovarian cancer, the results obtained highlight the importance of locating TP53 mutations.

Electronic supplementary material

The online version of this article (10.1186/s12935-018-0514-2) contains supplementary material, which is available to authorized users.

Regulation of signal transduction cascades by Pterostilbenes in different cancers: Is it a death knell for oncogenic pathways

Interdisciplinary research has revolutionized the field of medicine and we have witnessed exponential increase in the high-impact research in past few decades. However, the road to this burgeoning research field is obstacle-ridden because of intratumor heterogeneity, loss of apoptosis and dysregulation of spatio-temporally controlled signaling pathways. Ground-breaking findings obtained through genetic, genomic and proteomic studies have considerably improved our concepts related to the complexity of protein network and excitingly, discovery of miRNAs has added another layer of intricacy to quantitatively regulated gene networks. In this review, we chronicle the milestone achievements and discuss how Pterostilbenes effectively regulated different cellular pathways. We have provided detailed mechanistic insights related to regulation of JAK-STAT signaling, Notch pathway, Wnt mediated intracellular signaling by pterostilbene. Underlying mechanisms about regulation of PI3K/AKT and MAPK pathways by pterostilbene in different cancers.  Regulation of Metastasis-associated protein 1 (MTA1) proteins and Human telomerase reverse transcriptase (hTERT) in cancer cells by pterostilbene. Pterostilbene has also been reported to modulate the expression of various oncogenic and tumor suppressor microRNAs in cancer cells. Better and sharper comprehension of the concepts associated with the modes of action of pterostilbene in different cancers will be useful in identification of cancers which can be efficiently targeted by pterostilbene.

An Evaluation of the Stemness, Paracrine, and Tumorigenic Characteristics of Highly Expanded, Minimally Passaged Adipose-Derived Stem Cells

The use of adipose-derived stem cells (ADSC) in regenerative medicine is rising due to their plasticity, capacity of differentiation and paracrine and trophic effects. Despite the large number of cells obtained from adipose tissue, it is usually not enough for therapeutic purposes for many diseases or cosmetic procedures. Thus, there is the need for culturing and expanding cells in-vitro for several weeks remain. Our aim is to investigate if long- term proliferation with minimal passaging will affect the stemness, paracrine secretions and carcinogenesis markers of ADSC. The immunophenotypic properties and aldehyde dehydrogenase (ALDH) activity of the initial stromal vascular fraction (SVF) and serially passaged ADSC were observed by flow cytometry. In parallel, the telomerase activity and the relative expression of oncogenes and tumor suppressor genes were assessed by q-PCR. We also assessed the cytokine secretion profile of passaged ADSC by an ELISA. The expanded ADSC retain their morphological and phenotypical characteristics. These cells maintained in culture for up to 12 weeks until P4, possessed stable telomerase and ALDH activity, without having a TP53 mutation. Furthermore, the relative expression levels of TP53, RB, and MDM2 were not affected while the relative expression of c-Myc decreased significantly. Finally, the levels of the secretions of PGE₂, STC1, and TIMP2 were not affected but the levels of IL-6, VEGF, and TIMP 1 significantly decreased at P2. Our results suggest that the expansion of passaged ADSC does not affect the differentiation capacity of stem cells and does not confer a cancerous state or capacity in vitro to the cells.

The Interaction of CD154 with the α5β1 Integrin Inhibits Fas-Induced T Cell Death

CD154, a critical regulator of the immune response, is usually associated with chronic inflammatory, autoimmune diseases as well as malignant disorders. In addition to its classical receptor CD40, CD154 is capable of binding other receptors, members of the integrin family, the αIIbβ3, αMβ2 and α5β1. Given the role attributed to integrins and particularly the β1 integrins in inhibiting apoptotic events in normal as well as malignant T cells, we were highly interested in investigating the role of the CD154/α5β1 interaction in promoting survival of malignant T cells contributing as such to tumor development and/or propagation. To support our hypothesis, we first show that soluble CD154 binds to the T-cell acute lymphoblastic leukemia cell line, Jurkat E6.1 in a α5β1-dependent manner. Binding of soluble CD154 to α5β1 integrin of Jurkat cells leads to the activation of key survival proteins, including the p38 and ERK1/2 mitogen-activated protein kinases (MAPKs), phosphoinositide 3 kinase (PI-3K), and Akt. Interestingly, soluble CD154 significantly inhibits Fas-mediated apoptosis in T cell leukemia-lymphoma cell lines, Jurkat E6.1 and HUT78 cells, an important hallmark of T cell survival during malignancy progression. These anti-apoptotic effects were mainly mediated by the activation of the PI-3K/Akt pathway but also involved the p38 and the ERK1/2 MAPKs cascades. Our data also demonstrated that the CD154-triggered inhibition of the Fas-mediated cell death response was dependent on a suppression of caspase-8 cleavage, but independent of de novo protein synthesis or alterations in Fas expression on cell surface. Together, our results highlight the impact of the CD154/α5β1 interaction in T cell function/survival and identify novel targets for the treatment of malignant disorders, particularly of T cell origin.

The chemokine CCL20 induces proinflammatory and matrix degradative responses in cartilage

INTRODUCTION

Local inflammation plays a role in the pathophysiology of osteoarthritis (OA) and chemokines exert catabolic effects on articular cartilage either through paracrine and/or autocrine mechanisms. We sought to compare the expression levels of the chemokine (C-C motif) ligand 20 (CCL20) and its chemokine receptor 6 (CCR6) in donor and osteoarthritic (OA) cartilage and to investigate the role of CCL20 in the pathogenesis of OA and chondrocyte phenotype.

METHODS

Cartilage/chondrocytes from donor and OA knee joints was analyzed for CCL20 and CCR6 expression by RT-PCR and immunohistochemistry. Effects of CCL20 on cytokines and mediators of cartilage degradation were examined by RT-PCR for mRNA expression levels, enzyme-linked immunosorbent assays, and proteoglycan (GAG) assays.

RESULTS

CCL20 and CCR6 proteins were abundantly expressed in OA cartilage sections compared to donor sections as judged by immunohistochemistry. RT-PCR of cartilage extracts confirmed the predominance of CCL20/CCR6 mRNA expression in OA cartilage. CCL20 mRNA expression was low in donor chondrocytes but increased after stimulation with proinflammatory cytokines. mRNA expression levels of IL-6, cyclooxygenase-2, and iNOS were elevated in donor chondrocyte cultures treated with rhCCL20. The release of MMP1/13, PGE2, proteoglycan GAG fragments, and IL-6 from cartilage explant cultures was markedly augmented in the presence of CCL-20. CCL-20 stimulated MMP-13, ADAMTS-5, and col type X mRNA but inhibited col type II mRNA expression in freshly explanted and cultured cartilage specimens.

CONCLUSIONS

CCL20/CCR6 may play an important role in the pathogenesis of OA by inducing changes in phenotype and catabolic gene expression in chondrocytes.

Telomerase inhibition decreases alpha-fetoprotein expression and secretion by hepatocellular carcinoma cell lines: in vitro and in vivo study

Alpha-fetoprotein (AFP) is a diagnostic marker for hepatocellular carcinoma (HCC). A direct relationship between poor prognosis and the concentration of serum AFP has been observed. Telomerase, an enzyme that stabilizes the telomere length, is expressed by 90% of HCC. The aim of this study was to investigate the effect of telomerase inhibition on AFP secretion and the involvement of the PI3K/Akt/mTOR signaling pathway. Proliferation and viability tests were performed using tetrazolium salt. Apoptosis was determined through the Annexin V assay using flow cytometry. The concentrations of AFP were measured using ELISA kits. The AFP mRNA expression was evaluated using RT-PCR, and cell migration was evaluated using a Boyden chamber assay. The in vivo effect of costunolide on AFP production was tested in NSG mice. Telomerase inhibition by costunolide and BIBR 1532 at 5 and 10 μM decreased AFP mRNA expression and protein secretion by HepG2/C3A cells. The same pattern was obtained with cells treated with hTERT siRNA. This treatment exhibited no apoptotic effect. The AFP mRNA expression and protein secretion by PLC/PRF/5 was decreased after treatment with BIBR1532 at 10 μM. In contrast, no effect was obtained for PLC/PRF/5 cells treated with costunolide at 5 or 10 μM. Inhibition of the PI3K/Akt/mTOR signaling pathway decreased the AFP concentration. In contrast, the MAPK/ERK pathway appeared to not be involved in HepG2/C3A cells, whereas ERK inhibition decreased the AFP concentration in PLC/PRF/5 cells. Modulation of the AFP concentration was also obtained after the inhibition or activation of PKC. Costunolide (30 mg/kg) significantly decreased the AFP serum concentration of NSG mice bearing HepG2/C3A cells. Both the inhibition of telomerase and the inhibition of the PI3K/Akt/mTOR signaling pathway decreased the AFP production of HepG2/C3A and PLC/PRF/5 cells, suggesting a relationship between telomerase and AFP expression through the PI3K/Akt/mTOR pathway.

Glucose restriction decreases telomerase activity and enhances its inhibitor response on breast cancer cells: possible extra-telomerase role of BIBR 1532

Background

Considerable progress has been made to understand the association between lifestyle and diet in cancer initiation and promotion. Because excessive glucose consumption is a key metabolic hallmark of cancer cells, glucose restriction (GR) decreases the proliferation, and promotes the differentiation and transformation of cancer cells to quiescent cells. The immortality of cancerous cells is largely assured by telomerase, which is an interesting target for inhibition by BIBR 1532. In this study, we investigated the effect of GR on telomerase activity and on the efficacy of its inhibition by BIBR 1532.

Methods

Breast cancer MDA-MB 231 and MCF-7 cells were cultured in DMEM (Dulbecco’s modified eagle’s media) with 0, 1 or 4.5 g/l of glucose. The telomerase activity was measured via quantitative Real-Time PCR, and the two telomerase subunits were semi-quantified by RT-PCR. Proliferation test and mitochondrial metabolism were assessed via tetrazolium salt reduction and cell counts; apoptosis was assessed via caspase-3 quantification and flow cytometry.

Results

A decrease in the telomerase activity of more than 75% was associated with a significant reduction in the mRNA expression of its catalytic subunit hTERT (Reverse Transcriptase) and a decrease in the mitochondrial metabolism by more than 80% under restricted glucose conditions. In addition, GR increased the effect of BIBR 1532. Glucose deprivation induces apoptosis via BIBR 1532-mediated telomerase inhibition in triple negative breast cancer cells, as assessed by caspase-3 measurements and Annexin analysis.

Conclusions

Taken together, our results suggest that the effect of BIBR 1532 is potentiated by GR to induce triple negative breast cancer cell death.

Telomerase as a potential marker for inflammation and cancer detection in bronchial washing: a prospective study

OBJECTIVES

The diagnosis of lung cancer remains difficult especially in peripheral tumors, given the absence of relevant markers and of sensitive imaging techniques. Telomerase is a ribonucleotide enzyme responsible for the immortalization of cancerous cells and seems to increase in bronchial aspirates of lung cancer patients. The purpose of our study is to further investigate the value of telomerase measurement in bronchial aspirates as a diagnostic tool for lung cancer.

DESIGN AND METHODS

Random 82 bronchial aspirates were obtained from patients undergoing bronchoscopy to diagnose any lung illness including inflammation and cancer. Cytology examination, quantification of proteins by Bradford method, and telomerase activity measurement by quantitative Real-time PCR were performed. Out of 82 specimens, 11 were excluded because of hemolysis, absence of elements or lack of final diagnosis. ROC curve analysis was done.

RESULTS

A significant difference in telomerase activity average was noted between normal patients and those with inflammation and cancer. Discriminatory capacity of telomerase activity was: for cancer vs. non cancer, AUC =0.74 (95% CI: 0.62-0.84), sensitivity=78%, specificity=72%, Negative Predictive Value=87%, at cut-off >0.46 atmol/mg protein/20 min; for cancer vs. normal, AUC=0.87 (95% CI: 0.72-0.96), se=78%, sp=92%, NPV=71%, at cut-off >0.46; for cancer vs. inflammation, AUC=0.69 (95% CI: 0.55-0.80), se=74%, sp=70%, NPV=79%, at cut-off >1.03, and for inflammation vs. normal, AUC=0.76 (95% CI: 0.62-0.88), se=79%, sp=77%, NPV=59%, at cut-off >0.

CONCLUSION

Telomerase activity in bronchial aspirates is a promising diagnostic marker for lung cancer and inflammation detection.

CD154: the atherosclerotic risk factor in rheumatoid arthritis?

Atherosclerosis, now regarded as a chronic inflammatory disease of the arterial wall, and its clinical manifestations have increasingly been associated with rheumatoid arthritis (RA), supporting the notion that autoimmune diseases and vascular disorders share common etiological features. Indeed, evidence pertaining to this matter indicates that inflammation and its multiple components are the driving force behind the pathogenesis of these disorders. Interestingly, CD154 and its receptors have emerged as major players in the development of RA and atherosclerosis, which raises the possibility that this axis may represent an important biological link between both complications. Indeed, CD154 signaling elicits critical inflammatory responses that are common to the pathogenesis of both diseases. Here, we provide an overview of the traditional and disease-related interrelations between RA and vascular abnormalities, while focusing on CD154 as a potential mediator in the development of atherosclerotic events in RA patients.

Use of complementary and alternative therapy among patients with rheumatoid arthritis and osteoarthritis

AIMS AND OBJECTIVES

We wanted to assess the prevalence of complementary and alternative therapy use among patients suffering from rheumatoid arthritis or osteoarthritis in the Lebanese population and to determine the perceived efficacy and side effects of complementary and alternative therapy in the treatment of these diseases.

BACKGROUND

Complementary and alternative therapy has become popular among patients with chronic illnesses because of its widespread use. Rheumatoid arthritis and osteoarthritis are two diseases associated with severe pain, inflammation and limited activity. Although both are quite common in Lebanon, no studies were conducted in our country to portray complementary and alternative therapy use in their treatment.

DESIGN

Descriptive cross-sectional study.

METHODS

Conducted individualised questionnaire-based interviews among 250 adult patients, ranging between the ages of 20-90 years and diagnosed with either rheumatoid arthritis or osteoarthritis. The questionnaire included demographic information, clinical information, use of conventional therapies and complementary and alternative therapy, and the disease status before and after complementary and alternative therapy use.

RESULTS

Fifty-eight (23·2%) patients used complementary and alternative therapy in addition to their conventional medications in the treatment of either rheumatoid arthritis or osteoarthritis. Most herbal medicine users (63·8%) believed that complementary and alternative therapy was beneficial. The disease status measured by the intensity of pain, sleeping pattern and level of activities was significantly improved after using complementary and alternative therapy (p =0·01). Forty-eight (82·75%) patients were using herbals as complementary and alternative therapy, 14 (24·1%) of whom have sought medical care because of potential concomitant drug-complementary and alternative therapy side effects. However, these side effects were not serious and reversible.

CONCLUSION AND RECOMMENDATIONS

Although complementary and alternative therapy might have beneficial effects in rheumatoid arthritis and osteoarthritis, patients should be cautious about their use and should necessarily inform their health care providers about the consumption of any products other than their conventional medicines.

RELEVANCE TO CLINICAL PRACTICE

It is quite essential for health care professionals to be knowledgeable about the use of complementary and alternative medicine therapies when providing medical care to patients with arthritis.

Real-time reverse transcription-polymerase chain reaction quantification of tumor necrosis factor alpha messenger in human leukocytes

BACKGROUND

Tumor necrosis factor (TNF)-alpha plays a significant role in the pathogenesis of several inflammatory conditions. Several studies confirmed high TNF-alpha plasma protein levels in such conditions and highlighted the utility of TNF-alpha as a biomarker for disease progression or response to biological therapy. We aimed to provide a novel molecular technique for the measurement of TNF-alpha.

METHODS

Quantitative assay for the measurement of TNF-alpha messenger ribonucleic acid (mRNA) was done using real time reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

The test was specific, sensitive, and efficient and possessed a wide scale of linearity. Intrassay and interassay CVs were equivalent to those observed in enzyme-linked immunosorbent assay methods for plasmatic TNF-alpha. Data from 11 healthy adults recruited in an attempt to establish reference values showed an average of 109.4 ng of U937 RNA (range: 67.0 - 173.5). Circulating TNF-alpha protein was not detected by ELISA in any of the 11 subjects.

CONCLUSIONS

The test may be useful for clinical studies and in research investigating TNF-alpha gene expression both in physiologic and pathologic situations, although these pilot findings need to be confirmed through larger studies.

Early growth response factor-1 mediates prostaglandin E2-dependent transcriptional suppression of cytokine-induced tumor necrosis factor-alpha gene expression in human macrophages and rheumatoid arthritis-affected synovial fibroblasts

Tumor necrosis factor-alpha (TNF-alpha) is a pleiotropic proinflammatory cytokine that modulates a broad range of inflammatory and immunological processes. We have investigated the potential immunomodulatory properties of prostaglandin E2 (PGE2) by examining the molecular mechanism by which the eicosanoid suppresses T-cell-derived interleukin-17 (IL-17)-induced TNF-alpha mRNA expression and protein synthesis in human macrophages and rheumatoid arthritis-affected synovial fibroblasts. Initial studies confirmed that PGE2 induces egr-1 mRNA expression and protein synthesis by restricted SAPK2/p38 MAPK-dependent activating transcription factor-2 (ATF-2) dimer transactivation of the egr-1 promoter as judged by studies using wild-type (WT) and deletion mutant egr-1 promoter constructs, Northern and Western blotting, and standard and supershift electrophoretic mobility shift analyses. Using human leukemic monocytic THP-1 cells stably transfected with WT and dominant-negative mutant expression constructs of Egr-1, cotransfected or not with a WT pTNF-615SVOCAT construct, we observed that PGE2 inhibition of IL-17-stimulated TNF-alpha mRNA expression and promoter activity was dependent on Egr-1 expression, as mutants of Egr-1, alone or in combination, markedly abrogated any inhibitory effect of PGE2. Standard and supershift electrophoretic mobility shift analysis, signaling "decoy" overexpression studies, and pTNF-615SVOCAT promoter assays using WT and mutant promoter constructs revealed that IL-17-up-regulated promoter activity was largely dependent on ATF-2/c-Jun transactivation. PGE2 suppression of IL-17-induced ATF-2/c-Jun transactivation and DNA binding was dependent on Egr-1-mediated inhibition of induced c-Jun expression. We suggest that egr-1 is an immediate-early PGE2 target gene that may be a key regulatory factor in mediating eicosanoid control of genes involved in the immune and inflammatory responses.

Production of the chemokine RANTES by articular chondrocytes and role in cartilage degradation

OBJECTIVE

To examine the expression of the chemokine RANTES and its receptors in normal and osteoarthritic (OA) human cartilage and to analyze its effects on chondrocyte function.

METHODS

The expression of RANTES and its receptors were examined by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. The effect of RANTES on gene expression of other cytokines and on the release of mediators of cartilage degradation was also examined by PCR and enzyme-linked immunosorbent assay.

RESULTS

The expression of RANTES was undetectable in normal chondrocytes until after stimulation with interleukin-1beta (IL-1beta) or IL-18. Cultures of normal cartilage also produced RANTES in response to IL-1beta, as demonstrated by immunohistochemistry. All OA cartilage samples analyzed expressed RANTES messenger RNA (mRNA); RANTES protein was detected by immunohistochemistry in the superficial and mid zones of the tissue. OA chondrocytes produced elevated levels of RANTES constitutively and after IL-1beta stimulation. Normal cartilage expressed the RANTES receptors CCR3 and CCR5, but not CCR1. CCR1 was expressed in OA cartilage, and CCR3 and CCR5 were increased. In normal chondrocytes, RANTES induced the expression of inducible nitric oxide synthase and IL-6. RANTES stimulated the release of matrix metalloproteinase 1 in normal and OA chondrocytes as effectively as IL-1beta. Treatment of normal articular cartilage with RANTES increased the release of glycosaminoglycans and profoundly reduced the intensity of Safranin O staining.

CONCLUSION

Chondrocytes produce RANTES and express RANTES receptors. RANTES and CCR5 were markedly increased in OA and after in vitro treatment of normal chondrocytes with IL-1. Chondrocyte activation and cartilage degradation were identified as novel biologic and pathogenetic activities of this chemokine.

Production of the chemokine RANTES by articular chondrocytes and role in cartilage degradation

OBJECTIVE

To examine the expression of the chemokine RANTES and its receptors in normal and osteoarthritic (OA) human cartilage and to analyze its effects on chondrocyte function.

METHODS

The expression of RANTES and its receptors were examined by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. The effect of RANTES on gene expression of other cytokines and on the release of mediators of cartilage degradation was also examined by PCR and enzyme-linked immunosorbent assay.

RESULTS

The expression of RANTES was undetectable in normal chondrocytes until after stimulation with interleukin-1beta (IL-1beta) or IL-18. Cultures of normal cartilage also produced RANTES in response to IL-1beta, as demonstrated by immunohistochemistry. All OA cartilage samples analyzed expressed RANTES messenger RNA (mRNA); RANTES protein was detected by immunohistochemistry in the superficial and mid zones of the tissue. OA chondrocytes produced elevated levels of RANTES constitutively and after IL-1beta stimulation. Normal cartilage expressed the RANTES receptors CCR3 and CCR5, but not CCR1. CCR1 was expressed in OA cartilage, and CCR3 and CCR5 were increased. In normal chondrocytes, RANTES induced the expression of inducible nitric oxide synthase and IL-6. RANTES stimulated the release of matrix metalloproteinase 1 in normal and OA chondrocytes as effectively as IL-1beta. Treatment of normal articular cartilage with RANTES increased the release of glycosaminoglycans and profoundly reduced the intensity of Safranin O staining.

CONCLUSION

Chondrocytes produce RANTES and express RANTES receptors. RANTES and CCR5 were markedly increased in OA and after in vitro treatment of normal chondrocytes with IL-1. Chondrocyte activation and cartilage degradation were identified as novel biologic and pathogenetic activities of this chemokine.

N-acetylglucosamine prevents IL-1 beta-mediated activation of human chondrocytes

Glucosamine represents one of the most commonly used drugs to treat osteoarthritis. However, mechanisms of its antiarthritic activities are still poorly understood. The present study identifies a novel mechanism of glucosamine-mediated anti-inflammatory activity. It is shown that both glucosamine and N-acetylglucosamine inhibit IL-1beta- and TNF-alpha-induced NO production in normal human articular chondrocytes. The effect of the sugars on NO production is specific, since several other monosaccharides, including glucose, glucuronic acid, and N-acetylmannosamine, do not express this activity. Furthermore, N-acetylglucosamine polymers, including the dimer and the trimer, also do not affect NO production. The observed suppression of IL-1beta-induced NO production is associated with inhibition of inducible NO synthase mRNA and protein expression. In addition, N-acetylglucosamine also suppresses the production of IL-1beta-induced cyclooxygenase-2 and IL-6. The constitutively expressed cyclooxygenase-1, however, was not affected by the sugar. N-acetylglucosamine-mediated inhibition of the IL-1beta response of human chondrocytes was not associated with the decreased inhibition of the mitogen-activated protein kinases c-Jun N-terminal kinase, extracellular signal-related kinase, and p38, nor with activation of the transcription factor NF-kappaB. In conclusion, these results demonstrate that N-acetylglucosamine expresses a unique range of activities and identifies a novel mechanism for the inhibition of inflammatory processes.

Differential effects of IL-8, LIF (pro-inflammatory) and IL-11 (anti-inflammatory) on TNF-alpha-induced PGE(2)release and on signalling pathways in human OA synovial fibroblasts

Tumour necrosis factor alpha (TNF-alpha) inflammatory activity is mediated, at least in part, by prostaglandin E(2)(PGE(2)). In osteoarthritis (OA), other cytokines are believed to play a role by interacting with TNF-alpha. Using OA synovial fibroblasts, we investigated the effects of interleukin 8 (IL-8), leukaemia inhibitory factor (LIF) and IL-11 on the level of TNF-alpha-induced PGE(2), and their impact on the TNF-alpha-induced cellular signalling cascades including the TNF-receptor (TNF-R), soluble TNF-R (TNF-sR), cytoplasmic phospholipase A2 (cPLA2), cyclooxygenase 2 (COX-2), and the transcription factors NF-kappaB, C/EBP, CREB and AP-1.IL-8 increased in a synergistic manner (282% at 5 ng/ml) and LIF in an additive fashion (69% at 50 ng/ml) the TNF-alpha-induced PGE(2)release, while IL-11 reduced it (52% at 5 ng/ml). IL-8 (5 ng/ml) and LIF (50 ng/ml) alone upregulated (30%) the TNF-R binding level, but significantly downregulated the TNF-alpha-induced levels (P<0.007 and P<0.004, respectively) and the TNF-sR55 level. In contrast, IL-11 reduced the basal level by 18% (P<0.005) and the TNF-alpha-induced level of TNF-R by 51% (P<0.01) as well as decreasing both TNF-sR55 and TNF-sR75. The COX-2 synthesis level was increased by IL-8 and LIF under TNF-alpha treatment but downregulated by IL-11. IL-8 and LIF either alone or under TNF-alpha treatment increased the cPLA2 synthesis, while IL-11 decreased the level under both conditions. Interestingly, IL-8 induced in a synergistic manner and LIF in an additive fashion, the level of cPLA2 activity. IL-8 and LIF had no effect on the TNF-alpha-induced NF-kappaB accumulation, while IL-11 significantly decreased it (P<0. 02). All three cytokines inhibited TNF-alpha-induced C/EBP, but no true effect was noted for AP-1 and CREB in the presence of TNF-alpha. These results indicate that IL-8 synergizes and LIF potentiates the TNF-alpha PGE(2)effect which appears to be mediated mostly by increasing cPLA2 activity level. On the other hand, IL-11 alone had no effect on the PGE(2)release, but in conjunction with TNF-alpha, this cytokine showed anti-inflammatory properties. This study provides a rational foundation to develop therapeutic strategies for the treatment of OA by shedding light on the mechanisms of action of three prominent cytokines at work in articular joint tissues.

Cytokines and their role in the pathophysiology of osteoarthritis

The specific causative agent of the pathological process of osteoarthritis (OA) has not yet been identified, however, episodic inflammation at the clinical stage is now a well documented phenomenon and believed to be involved in the disease progression. Interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) are the predominant proinflammatory cytokines synthesized during the OA process. Other cytokines having proinflammatory properties or catabolic factors could also contribute to this pathological condition, and those having antiinflammatory properties may be able to counteract the negative effects of the former on the disease process. In this chapter, we will review cytokine interactions and their modulatory effects on joint articular tissue metabolism, including their stimulatory and/or inhibitory actions, and their potential relevance to OA. We will also briefly survey the major biological factors, in relation to cytokines, that look promising for future therapeutic approaches.

Effect of nimesulide on glucocorticoid receptor activity in human synovial fibroblasts

Fibroblasts from human synovial membranes were cultured with nimesulide, naproxen or dexamethasone. Nimesulide, but not naproxen, showed effects on the glucocorticoid system that may contribute importantly to its anti-inflammatory activity. Nimesulide at therapeutically relevant concentrations induced the intracellular phosphorylation and activation of glucocorticoid receptors, and activated their binding to the target genes. Naproxen or dexamethasone markedly reduced the number of glucocorticoid receptor binding sites, in contrast to nimesulide, which had no significant effect.

Inhibition of tumor necrosis factor alpha-induced prostaglandin E2 production by the antiinflammatory cytokines interleukin-4, interleukin-10, and interleukin-13 in osteoarthritic synovial fibroblasts: distinct targeting in the signaling pathways

OBJECTIVE

To investigate the effects of the antiinflammatory cytokines interleukin-4 (IL-4), IL-10, and IL-13 on tumor necrosis factor alpha (TNFalpha)-induced prostaglandin E2 (PGE2) release in the cellular signaling cascade on human osteoarthritis (OA) synovial fibroblasts.

METHODS

Human OA synovial fibroblasts were cultured to explore the impact of IL-4, IL-10, and IL-13 on TNFalpha binding to TNF receptors (TNFR), soluble TNFR (sTNFR), cytoplasmic phospholipase A2 (cPLA2), and cyclooxygenase-2 (COX-2) production, and on the binding activity of the transcription factors nuclear factor kappaB (NF-kappaB), CCAAT-enhancer binding protein (C/EBP), activator protein 2 (AP-2), and cyclic AMP response element-binding protein (CREB).

RESULTS

IL-4, IL-10, and IL-13 at 5 ng/ml dramatically reduced TNFalpha-induced PGE2 release by approximately 90% (P < 0.0001). IL-4 up-regulated the level of TNFalpha-induced TNFR by 47% (P < 0.06), while IL-10 down-regulated it by 71% (P < 0.02); IL-13 had no effect. Although statistical significance was not reached, all 3 cytokines up-regulated the basal level of sTNFR-55. IL-4 and IL-10, while not altering the basal level of sTNFR-75, significantly increased the TNFalpha-stimulated release of sTNFR-75. IL-4, IL-10, and IL-13 reduced the TNFalpha-induced COX-2 level, and IL-4 and IL-10 reduced the cPLA2 level. IL-4 had no effect on TNFalpha up-regulation of NF-kappaB, and a slight decrease was noted with IL-10 and IL-13 at the highest concentration used (5 ng/ml). IL-4 and IL-13 decreased the TNFa-induced C/EBP accumulation in a dose-dependent manner, while IL-10 up-regulated its basal level. AP-2 and CREB were not induced by TNFalpha.

CONCLUSION

The results indicate that these antiinflammatory cytokines reversed the TNFalpha-induced release of PGE2 by OA synovial fibroblasts, by acting at various levels of the TNFa-dependent signaling cascade. These data shed new light on the mechanisms by which these cytokines reduce inflammatory processes.

Enhancement of phosphorylation and transcriptional activity of the glucocorticoid receptor in human synovial fibroblasts by nimesulide, a preferential cyclooxygenase 2 inhibitor

OBJECTIVE

To examine the effect of 2 nonsteroidal antiinflammatory drugs (NSAIDs), nimesulide (NIM), a preferential cyclooxygenase 2 (COX-2) inhibitor, and naproxen (NAP), on the functional parameters and transcriptional activity of the glucocorticoid receptor (GR) system in cultured human synovial fibroblasts (HSF).

METHODS

HSF were incubated with NIM (0.3, 3, and 30 microg/ml), NAP (15, 30, and 90 microg/ml), and dexamethasone (DEX; 0.01, 0.1, and 1 microM) on a time- and dose-dependent basis. The numbers of GR binding sites per cell were determined by radioligand receptor assay. Total cellular, cytoplasmic, or nuclear GR protein was measured by Western analysis using a specific anti-human GR antibody. Phosphorylation of GR was determined by specific immunoprecipitation of protein extracts from 32P-orthophosphate-labeled HSF. Mitogen-activated protein kinase p44/42 (MAPK) phosphorylation was followed by Western analysis using a specific anti-phosphoMAPK antibody. Levels of activated nuclear GR capable of binding specifically to a 32P-labeled oligonucleotide harboring the glucocorticoid/hormone response element (GRE) were evaluated by gel electrophoretic mobility shift analysis. The effects of NIM and DEX on transcriptional activation of the mouse mammary tumor virus (MMTV) promoter was determined by transfecting HSF with MMTV-luciferase (reporter gene) constructs.

RESULTS

NIM had no effect on the number of GR binding sites, in contrast to NAP and DEX. NIM and NAP did not influence cellular GR protein levels or nucleocytoplasmic shuttling, although DEX lowered GR messenger RNA and protein levels after 48 hours. NIM, but not NAP, markedly increased MAPK phosphorylation (suggesting an increase in MAPK cascade activity), GR phosphorylation, GR binding to GRE, and transcriptional activation of MMTV promoter through the GRE site in the promoter.

CONCLUSION

This study is the first to report that the antiinflammatory effects of NIM, an NSAID, may be partly related to its activation of the GR system.

Effect of IL-13 on cytokines, cytokine receptors and inhibitors on human osteoarthritis synovium and synovial fibroblasts

OBJECTIVE

In this study we investigated the effect of interleukin-13 (IL-13), an anti-inflammatory cytokine, for potential therapeutic use in osteoarthritis (OA).

DESIGN

We examined the effect of IL-13 on the synthesis and expression of interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), IL-1 receptor antagonist (IL-1Ra) and stromelysin-1 on human OA synovial membrane in ex vivo cultures. In addition, we explored the effect of IL-13 on both the IL-1 receptor (IL-1R) and TNF-receptor (TNF-R) systems on OA synovial fibroblasts. This included determination of the levels of IL-1 beta and TNF-alpha receptor binding, IL-1Ra and TNF-soluble receptors 55 and 75 (TNF-sR55 and TNF-sR75).

RESULTS

In OA synovial membrane treated with LPS, IL-13 inhibited the synthesis of IL-1 beta, TNF-alpha and stromelysin-1, but increased IL-1Ra production. In addition, IL-13 reduced the level of IL-1 beta mRNA and stimulated the level of IL-1Ra mRNA. In synovial fibroblasts, IL-13 decreased the level of IL-1 binding, an effect related to the increased production of IL-1Ra. Although IL-13 had no effect on the TNF-R level, this cytokine markedly decreased the shedding of TNF-R75.

CONCLUSION

These experiments suggest that IL-13 is potentially useful in the therapeutic treatment of OA, as it could regulate the major pathological process of this disease by reducing the production of proinflammatory cytokines and metalloproteases, and favoring the production of IL-1Ra.

Osteoarthritic synovial fibroblasts possess an increased level of tumor necrosis factor-receptor 55 (TNF-R55) that mediates biological activation by TNF-alpha

OBJECTIVE

To investigate the presence, number, and level of expression of tumor necrosis factor receptors (TNF-R) in normal and osteoarthritic (OA) human synovial fibroblasts; to examine which receptor isotype mediates the biological response of these cells to TNF-alpha; and to study homologous regulatory mechanisms of TNF-R by TNF-alpha.

METHODS

We used radioligand binding assay with [125I]TNF-alpha and flow cytometric analysis with specific antireceptor antibodies to characterize receptor populations, densities, and ligand induced internalization of TNF-R. Inducible cyclooxygenase (COX-2) synthesis, prostaglandin E2 (PGE2) release, and TNF-R shedding (soluble receptors, TNF-sR) were measured after incubation with TNF-alpha the presence or absence of receptor specific blocking antibodies.

RESULTS

Although radioligand binding assays showed no difference in the density or affinity of TNF-R in OA synovial fibroblasts compared with normal cells, flow cytometric analysis revealed that OA cells express a significantly higher level of TNF-R55 (p < 0.04) than normal cells. The TNF-R55 was found to be the major receptor species responsible for ligand binding activity, such as COX-2 induction and PGE2 synthesis, since a specific antireceptor TNF-R55 blocking antibody inhibited about 76% of TNF-alpha binding and TNF-alpha stimulated COX-2 induction and PGE2 production. Further experiments revealed that TNF-R55 was the only receptor type internalized after binding TFN-alpha, whereas TNF-R75 was concomitantly shed. Moreover, reducing the shedding of TNF-sR, particularly the TNF-sR75, with a synthetic inhibitor decreased TNF-alpha induced PGE2 production.

CONCLUSION

TNF-R55 is the major receptor isoform transducing PGE2 and COX-2 responses to TNF-alpha in OA synovial fibroblasts; soluble receptors could be involved in facilitating the binding of TNF-alpha to its receptor.