Adrenomedullin Inhibits IL-1β-Induced Rheumatoid Synovial Fibroblast Proliferation and MMPs, COX-2 and PGE2 Production

Serum level of Adrenomedullin in patients with primary knee osteoarthritis; relation to disease severity

Background

Adrenomedullin (AM) is a peptide which was suggested to be involved in the pathogenesis of osteoarthritis through its anti-inflammatory and anti-apoptotic effect. AM was found to be elevated in some inflammatory rheumatic diseases as rheumatoid arthritis and ankylosing spondylitis.

The current study was performed to measure serum Adrenomodullin (AM) concentrations in patients with primary knee osteoarthritis (KOA) and to assess association with severity of the disease. The study was performed on 50 patients with primary KOA diagnosed according to American College of Rheumatology (ACR) Revised Criteria for Early Diagnosis of Knee Osteoarthritis and 20 age- and sex-matched controls with no clinical features of KOA. The Kellgren and Lawrence (KL) classification was used to evaluate the disease severity of knee OA. Disease activity was assessed by The Western Ontario and McMaster Universities Arthritis Index (WOMAC). Blood samples had been collected from patients with OA and controls for assessing Adrenomodullin in patients’ sera by ELISA.

Results

There were a significant increase in serum Adrenomedullin concentrations in KOA patients compared to controls (10.64 ±19.2 ng/ml vs. 1.39 ±1.6 ng/ml in cases and controls respectively) (p value = 0.036). There was positive significant correlation of serum Adrenomedullin levels with KL grades (r=0.608, p value <0.001). OA patients with VAS score >6 have significantly higher serum Adrenomedullin levels than OA patients with VAS Score <6. No detected significant correlation between any of (patients’ age, BMI, disease duration, tenderness score, and WOMAC score) with serum Adrenomedullin levels among studied OA cases (p values >0.05).

Conclusion

This study concluded that serum Adrenomedullin (AM) level is elevated in patients with KOA and is positively correlated with the severity of disease.

Fucoidan isolated from Hizikia fusiforme suppresses ultraviolet B-induced photodamage by down-regulating the expressions of matrix metalloproteinases and pro-inflammatory cytokines via inhibiting NF-κB, AP-1, and MAPK signaling pathways

Overexposure to ultraviolet B (UVB) causes skin damage. The purpose of this study was to evaluate the protective effect of a fucoidan with a molecular weight of 102.67 kDa, isolated from Hizikia fusiforme, against UVB-induced photodamage in vitro in human dermal fibroblasts (HDFs) and in vivo in zebrafish. Fucoidan remarkably inhibited commercial collagenase. Additionally, it significantly and dose-dependently decreased the intracellular reactive oxygen species (ROS) levels and increased the viability of UVB-irradiated HDFs. Furthermore, fucoidan remarkably improved collagen synthesis, inhibited intracellular collagenase, and reduced the expression of matrix metalloproteinases and pro-inflammatory cytokines in UVB-irradiated HDFs. Further research demonstrated that these effects occurred through the regulation of the activator protein 1, nuclear factor kappa B, and mitogen-activated protein kinase signaling pathways. Furthermore, the in vivo results showed that fucoidan protected zebrafish larvae against UVB-induced photodamage by decreasing cell death via the suppression of lipid peroxidation and inflammatory response through ROS clearance. In conclusion, fucoidan isolated from Hizikia fusiforme exhibits strong in vitro and in vivo photoprotective effects, and can be used as an ingredient in the cosmeceutical and pharmaceutical industries.

Adrenomedullin protects rat dorsal root ganglion neurons against doxorubicin-induced toxicity by ameliorating oxidative stress

OBJECTIVES

Despite effective anticancer effects, the use of doxorubicin (DOX) is hindered due to its cardio and neurotoxicity. The neuroprotective effect of adrenomedullin (AM) was shown in several studies. The present study aimed to evaluate the possible protective effects of AM against DOX-induced toxicity in dorsal root ganglia (DRGs) neurons.

MATERIALS AND METHODS

Rat embryonic DRG neurons were isolated and cultured. The effect of various concentrations of DOX (0.0 to 100 µM) in the absence or presence of AM (3.125 -100 nM) on cell death, apoptosis, oxidative stress, expression of tumor necrosis-α (TNF-α), interleukin1- β (IL-1β), inducible nitric oxide synthase (iNOS), matrix metalloproteinase (MMP) 3 and 13, and SRY-related protein 9 (SOX9) were examined.

RESULTS

Based on MTT assay data, DOX decreased the viability of DRG neurons in a dose and time-dependent manner (IC50=6.88 µm) while dose-dependently, AM protected DRG neurons against DOX-induced cell death. Furthermore, results of annexin V apoptosis assay revealed the protective effects of AM (25 nm) against DOX (6.88 µM)-induced apoptosis and necrosis of DRG neurons. Also, AM significantly ameliorated DOX-induced oxidative stress in DRG neurons. Real-time PCR results showed a significant increase in the expression of TNF-α, IL-1β, iNOS, MMP 3, and MMP 13, and a decrease in the expression of SOX9 following treatment with DOX. Treatment with AM (25 nM) significantly reversed the effects of DOX on the above-mentioned genes expression.

CONCLUSION

Our findings suggest that AM can be considered a novel ameliorating drug against DOX-induced neurotoxicity.

Low intensity pulsed ultrasound increases mandibular height and Col-II and VEGF expression in arthritic mice

OBJECTIVE

Rheumatoid arthritis (RA) is a chronic inflammatory disease involving persistent inflammation resulting in cartilage and bone damage. RA can affect the temporomandibular joint (TMJ), and damage to the TMJ condyle can lead to craniofacial developmental disturbances, causing micrognathia, malocclusion, retrognathia, and increased overjet. Current treatments of TMJ arthritis are unsatisfactory. This pilot study aimed to investigate the effect of low intensity pulsed ultrasound (LIPUS) on the mandible and TMJ condyles in an RA mouse model using micro-computed tomography (Micro-CT), histologic, and immunohistochemical analyses.

METHODS

MRL-lpr/lpr mice received LIPUS application to their TMJs for 20 min/day for 2 and 4 weeks. Micro-CT analysis measured condylar length and width, posterior mandibular height (P.M.H), mandibular ramus length (M.R.L), effective mandibular length (Ef.M.L), angular process length (A.P.L), mandibular plane (M.P), mandibular axis (M.Ax), and lower incisor height (L.I.H). Condylar cartilage thickness was histologically measured, and type II collagen (Col-II), vascular endothelial growth factor (VEGF), nuclear factor kappa-B ligand (RANKL), and osteoprotegerin (OPG) expression was analyzed using immunohistochemistry.

RESULTS

Comparing the LIPUS-treated group with the control, P.M.H, M.R.L, and M.P were significantly greater in the LIPUS-treated group. Immunostaining for Col-II and VEGF was stronger in the LIPUS-treated group after 4 weeks. OPG showed slightly more expression in the LIPUS group.

CONCLUSIONS

LIPUS may enhance mandibular and TMJ condylar bone formation in this RA mouse model by preventing any growth disturbances involved in inflammation. Further studies are recommended to analyze the effect of LIPUS on TMJ of RA in other animal models.

Mesenchymal stem cells overexpressing adrenomedullin improve heart function through antifibrotic action in rats experiencing heart failure

Previous studies of the authors have indicated that the transplantation of mesenchymal stem cells (MSCs) can attenuate cardiac fibrosis through the secretion of antifibrotic factors, such as adrenomedullin (ADM). Therefore, the authors addressed the hypothesis that ADM overexpression could enhance the antifibrotic effect of MSCs transplantation in a rat model of heart failure. The results of the present study demonstrated that, compared with the group that received the GFP-MSCs, the transplantation of ADM-MSCs significantly improved heart function and decreased the percentage of fibrotic area and the expression of matrix metalloproteinase 2. In addition, fluorescence microscopy indicated that the survival of transplanted MSCs also increased significantly in the ADM-MSCs-treated group. Furthermore, the expression of fibrosis-related genes, such as ADM and hepatocyte growth factor, were significantly influenced in the ADM-MSCs-treated group. Based on these findings, it may be concluded that, compared with MSCs, MSCs overexpressing ADM can further improve heart function in rats experiencing heart failure through enhanced antifibrotic activity.

KCa1.1 channels regulate β1-integrin function and cell adhesion in rheumatoid arthritis fibroblast-like synoviocytes

Large-conductance calcium-activated potassium channel (KCa1.1; BK, Slo1, MaxiK, KCNMA1) is the predominant potassium channel expressed at the plasma membrane of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs) isolated from the synovium of patients with RA. It is a critical regulator of RA-FLS migration and invasion and therefore represents an attractive target for the therapy of RA. However, the molecular mechanisms by which KCa1.1 regulates RA-FLS invasiveness have remained largely unknown. Here, we demonstrate that KCa1.1 regulates RA-FLS adhesion through controlling the plasma membrane expression and activation of β₁ integrins, but not α₄, α₅, or α₆ integrins. Blocking KCa1.1 disturbs calcium homeostasis, leading to the sustained phosphorylation of Akt and the recruitment of talin to β₁ integrins. Interestingly, the pore-forming α subunit of KCa1.1 coimmunoprecipitates with β₁ integrins, suggesting that this physical association underlies the functional interaction between these molecules. Together, these data outline a new signaling mechanism by which KCa1.1 regulates β₁-integrin function and therefore invasiveness of RA-FLSs.-Tanner, M. R., Pennington, M. W., Laragione, T., Gulko, P. S., Beeton, C. KCa1.1 channels regulate β₁-integrin function and cell adhesion in rheumatoid arthritis fibroblast-like synoviocytes.

Correlation of Adrenomedullin Concentrations with Knee Osteoarthritis Grade

BACKGROUND Adrenomedullin, a recently identified myokine, has an anti-inflammatory effect. Therefore, we aimed to assess the correlation of adrenomedullin concentrations with the presence and grade of severity of knee osteoarthritis (OA). MATERIAL AND METHODS We recruited 187 knee OA patients and 109 healthy subjects. The severity of OA was evaluated using the Kellgren-Lawrence grading system. RESULTS Compared with the control group, the knee OA group revealed markedly higher adrenomedullin concentrations. Serum and synovial fluid (SF) adrenomedullin concentrations increased with increased KL grades. CONCLUSIONS Serum and SF adrenomedullin concentrations show a correlation with the severity of knee OA.

Macrophage migration inhibitory factor enhances lipopolysaccharide-induced fibroblast proliferation by inducing toll-like receptor 4

BACKGROUND

Fibroblast proliferation is a common manifestation of chronic inflammatory diseases, including rheumatoid arthritis (RA), Crohn's disease and ulcerative colitis, etc. To alleviate patient suffering, the mechanism underlying fibroblast proliferation should be elucidated.

METHODS

CCK-8 assay was used to assess the stimulatory effect of LPS and macrophage migration inhibitory factor (MIF) on fibroblast proliferation. Then, TLR4 expression on fibroblast cell membrane was carried out by confocal scanning microscopy. Finally, real-time fluorescent quantitative PCR and flow cytometry were applied to determine the expression of TLR4 after MIF challenge.

RESULTS

LPS alone directly stimulated the fibroblast proliferation. In addition, MIF showed co-stimulatory effect on LPS-induced fibroblast proliferation. Interestingly, fibroblast overtly expressed TLR4 without stimulation. After MIF stimulation, real-time PCR showed TLR4 mRNA levels were increased by about 33% in the fibroblasts; in agreement, TLR4 expression on the fibroblast membrane was increased by about 20%, as shown by flow cytometry.

CONCLUSIONS

These findings indicated MIF elevates TLR4 expression in fibroblast, enhancing LPS-induced cell proliferation.

Neuropeptide receptors as potential drug targets in the treatment of inflammatory conditions

Cross-talk between the nervous, endocrine and immune systems exists via regulator molecules, such as neuropeptides, hormones and cytokines. A number of neuropeptides have been implicated in the genesis of inflammation, such as tachykinins and calcitonin gene-related peptide. Development of their receptor antagonists could be a promising approach to anti-inflammatory pharmacotherapy. Anti-inflammatory neuropeptides, such as vasoactive intestinal peptide, pituitary adenylate cyclase-activating polypeptide, α-melanocyte-stimulating hormone, urocortin, adrenomedullin, somatostatin, cortistatin, ghrelin, galanin and opioid peptides, are also released and act on their own receptors on the neurons as well as on different inflammatory and immune cells. The aim of the present review is to summarize the most prominent data of preclinical animal studies concerning the main pharmacological effects of ligands acting on the neuropeptide receptors. Promising therapeutic impacts of these compounds as potential candidates for the development of novel types of anti-inflammatory drugs are also discussed.

GeneChip expression profiling reveals the alterations of energy metabolism related genes in osteocytes under large gradient high magnetic fields

The diamagnetic levitation as a novel ground-based model for simulating a reduced gravity environment has recently been applied in life science research. In this study a specially designed superconducting magnet with a large gradient high magnetic field (LG-HMF), which can provide three apparent gravity levels (μ-g, 1-g, and 2-g), was used to simulate a space-like gravity environment. Osteocyte, as the most important mechanosensor in bone, takes a pivotal position in mediating the mechano-induced bone remodeling. In this study, the effects of LG-HMF on gene expression profiling of osteocyte-like cell line MLO-Y4 were investigated by Affymetrix DNA microarray. LG-HMF affected osteocyte gene expression profiling. Differentially expressed genes (DEGs) and data mining were further analyzed by using bioinfomatic tools, such as DAVID, iReport. 12 energy metabolism related genes (PFKL, AK4, ALDOC, COX7A1, STC1, ADM, CA9, CA12, P4HA1, APLN, GPR35 and GPR84) were further confirmed by real-time PCR. An integrated gene interaction network of 12 DEGs was constructed. Bio-data mining showed that genes involved in glucose metabolic process and apoptosis changed notablly. Our results demostrated that LG-HMF affected the expression of energy metabolism related genes in osteocyte. The identification of sensitive genes to special environments may provide some potential targets for preventing and treating bone loss or osteoporosis.

Low-intensity pulsed ultrasound reduces the inflammatory activity of synovitis

The purpose of this study was to examine the effect of low-intensity pulsed ultrasound (LIPUS) on the cell proliferation and growth of synovial membrane cells stimulated with inflammatory cytokines, and to evaluate the effectiveness of LIPUS treatment of synovitis in the knee joints of animal models for rheumatoid arthritis. The rabbit knee synovial membrane cell line, HIG-82, was cultured in medium with or without IL-1β or TNF-α. Four hours after stimulation with the cytokines, the cells received LIPUS or sham exposure. Cell proliferation and growth were then analyzed. Using MRL/lpr mice, the anti-inflammatory effects of LIPUS were also evaluated in vivo. Stimulation with proinflammatory cytokines significantly up-regulated cell proliferation which was significantly down-regulated by LIPUS exposure. In MRL/lpr mice, exposure of knee joints to LIPUS caused a significant reduction of histological damage compared to the control. Histological lesions were significantly reduced in the joints treated with LIPUS for 3 weeks. Cox-2-positive cells in the knee joints treated with LIPUS were markedly decreased compared to the control joints. Therefore, LIPUS stimulation may be a medical treatment for joint inflammatory diseases, such as synovitis.

Vascular contribution of adrenomedullin to microcirculatory improvement in experimental colitis

The effect of adrenomedullin (AM), a peptide that has demonstrated vasodilatory activity, was studied in the colon and small mesenteric arteries of rats in a chronic model of inflammatory bowel disease. AM (50 ng/kg/day) was administered i.p. daily, starting 24h after trinitrobenzensulfonic acid (TNBS, 30 mg) instillation. After 14 days, rats were sacrificed, colons were macroscopically analyzed and biochemical parameters (myeloperoxidase activity, cytokines, cyclooxygenase-2 (COX-2) as well as inducible nitric oxide synthase (iNOS) expression) were determined. Vascular function of small mesenteric arteries was assessed by addition of phenylephrine (10⁻⁸ to 10⁻⁴ mol/L) and participation of COX and NOS pathways was also evaluated by using different inhibitors: indomethacin, NS-398, L-NNA, and 1400 w. Chronic AM treatment significantly reduced colonic macroscopic damage and inflammation markers. TNBS instillation induced COX-2 and iNOS expressions in colon and small mesenteric arteries; AM treatment decreased COX-2 expression only in microvessels from rats with colitis. An attenuation of phenylephrine-induced contraction was detected in small mesenteric arteries from both TNBS and AM-treated rats. COX and NOS inhibitors altered the contractile ability of phenylephrine in small mesenteric arteries from TNBS rats, suggesting the involvement of COX-2 and iNOS derived factors in the deleterious effect of TNBS on vascular reactivity; AM administration was able to reduce such alteration. Finally, treatment with the peptide significantly reduced colonic nitric oxide (NO) levels, without affecting plasma concentration. In conclusion, AM showed beneficial effects in the restoration of vascular function through the regulation of vasoactive products derived from COX-2 and iNOS.