Short-term hyperthermia prevents activation of proinflammatory genes in fibroblast-like synoviocytes by blocking the activation of the transcription factor NF-κB

The landscape of pathophysiology guided therapeutic strategies for gout treatment

INTRODUCTION

Gout is a common autoinflammatory disease caused by hyperuricemia with acute and/or chronic inflammation as well as tissue damage. Currently, urate-lowering therapy (ULT) and anti-inflammatory therapy are used as first-line strategies for gout treatment. However, traditional drugs for gout treatment exhibit some unexpected side effects and are not suitable for certain patients due to their comorbidity with other chronic disease.

AREAS COVERED

In this review, we described the pathophysiology of hyperuricemia and monosodium urate (MSU) crystal induced inflammatory response during gout development in depth and comprehensively summarized the advances in the investigation of promising ULT drugs as well as anti-inflammatory drugs that might be safer and more effective for gout treatment.

EXPERT OPINION

New drugs that are developed based on these molecular mechanisms exhibited great efficacy on reduction of disease burden both in vitro and in vivo, implying their potential for clinical application. Moreover, hyperthermia also showed regulation effect on MSU crystals formation and the signaling pathways involved in inflammation.

4-Iodo-6-phenylpyrimidine (4-IPP) suppresses fibroblast-like synoviocyte- mediated inflammation and joint destruction associated with rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic immune-mediated inflammatory disease that significantly impacts patients' quality of life. Fibroblast-like synovial cells (FLSs) within the synovial intima exhibit "tumor-like" properties such as increased proliferation, migration, and invasion. Activation of FLSs and secretion of pro-inflammation factors result in pannus formation and cartilage destruction. As an inhibitor of the cytokine, macrophage migration inhibitory factor (MIF), 4-Iodo-6-phenylpyrimidine (4-IPP) has been shown to reduce cell proliferation, migration, invasion, and the secretion of pro-inflammatory mediators in a variety of diseases. However, the usefulness of 4-IPP for RA treatment has not been assessed and was the purpose of this study. In vitro, 4-IPP was demonstrated to inhibit proliferation, migration, and invasion of RA FLSs, as well as the expression of pro-inflammatory cytokines. 4-IPP was also shown to inhibit MIF-induced phosphorylation of ERK, JNK, and p38, as well as reduce expression of COX2 and PGE2. In order to efficiently deliver 4-IPP to anatomical RA sites, we developed lactic-co-glycolic acid (PLGA) nanospheres, which not only protected 4-IPP from degradation but also controlled the release of 4-IPP. 4-IPP/PLGA nanospheres had potent anti-inflammatory activity and a high degree of biosafety. Results showed that local 4-IPP concentration was increased by nanosphere delivery, effectively reducing the inflammatory microenvironment as well as synovial inflammation, joint swelling, and cartilage destruction in a collagen-induced rheumatoid arthritis (CIA) rat model. Therefore, 4-IPP nanospheres are a sustained-release delivery system that may be an effective therapeutic strategy for RA treatment.

From traditional to novel treatment of arthritis: a review of recent advances in nanotechnology-based thermal therapy

Arthritis has been a heavy burden on the economy and society at large. Recently, nanomaterials that can convert near-infrared light into localized heat have demonstrated better targeting to arthritic joints, fewer side effects, ease of combined application with current therapeutics and enhanced efficacy for arthritis treatment. In this review, the authors summarize traditional thermal therapies for arthritis treatment and their molecular mechanisms and discuss the advantages and applications of nanotechnology-based thermal therapies for arthritis treatment. In conclusion, nanotechnology-based thermal therapies are effective alternatives or adjuvant strategies to the current pharmacological treatment of arthritis. Future clinical translation of thermal therapies could benefit from research elucidating their mechanisms and standardizing their parameters to optimize efficacy.

Methotrexate-loaded multifunctional nanoparticles with near-infrared irradiation for the treatment of rheumatoid arthritis

Backgrounds

Despite the advances of rheumatoid arthritis (RA) therapeutics, several patients do not receive adequate treatment due to the toxicity and/or insufficient response of drugs. The aim of this study is to design photothermally controlled drug release from multifunctional nanoparticles (MNPs) at a near-infrared (NIR) irradiated site to improve therapeutic efficacy for RA and reduce side effects.

Methods

Au film was deposited onto methotrexate (MTX)-loaded poly(ethylene glycol)-poly(lactic-co-glycolic acid) (PLGA) nanoparticles, resulting in MTX-loaded MNPs. The synergistic effects of MTX-loaded MNPs with NIR irradiation were investigated using RA fibroblast-like synoviocytes (FLSs) and collagen-induced arthritis (CIA) mice.

Results

Upon NIR irradiation, NIR resonance of the Au half-shell generated heat locally, accelerating MTX release from PLGA nanoparticles. In vivo NIR images of MTX-loaded MNPs indicated effective delivery of the MNPs to the inflamed joints. Moreover, in collagen-induced arthritis mice, MTX-loaded MNPs containing 1/1400 of MTX solution (repeated-dose administration) had therapeutic effects comparable to conventional treatment with MTX solution. In vitro experiments showed higher therapeutic efficacy of MTX-loaded MNPs with NIR irradiation than that of chemotherapy alone.

Conclusions

A combination therapy of MTX-loaded MNP and NIR irradiation showed durable and good treatment efficacy for the suppression of arthritis in a single administration of small dose of MTX. Our results demonstrate that the treatment modality using drug-loaded MNP with NIR irradiation may be a promising therapeutic strategy for the treatment of RA and allow in vivo NIR optical imaging.

[Mild stress as a means to modulate aging: from fly to human?]

Hormesis is the phenomenon by which adaptive responses to low doses of otherwise harmful conditions improve the functional ability of organisms. Some mild stresses have beneficial effects on longevity, aging and resistance to strong stresses (heat or cold shocks, infection) in Drosophila flies. Studies on rodents are indeed scarce but mild stress seems to be effective in humans because, for instance, patients suffering from angina have a higher survival when confronted with a heart attack. A few studies, in less tragic situations however, suggest that mild stress could have positive effects in elderly people. Performing more experiments on the effects of mild stress in humans would help to know whether it could be used in therapy or to improve healthspan of elderly.

NF-kappaB independent activation of a series of proinflammatory genes by hydrogen sulfide

A stress response has the potential to induce greater resistance to subsequent stress damage. We tested whether hydrogen sulfide (H(2)S), an important signaling molecule, also used therapeutically, and known for detrimental effects, might induce a protective stress response. Therefore, the response of fibroblast-like synoviocytes (FLS) treated with sodium hydrosulfide and mice exposed to H(2)S were examined. In both cases a profound and long lasting induction of the stress-response could be detected. However, despite the sustained presence of large levels of HO-1 and HSP-70, proinflammatory effects of exposure to IL-1beta or H(2)S itself were not ameliorated. On the contrary, at H(2)S concentrations significantly lower than 10 ppm-the current maximal allowable concentration of H(2)S in many countries-COX-2, IL-8, IL-1alpha, IL-1beta and TNFalpha were dose dependently elevated. Importantly, in FLS, short-term exposure to H(2)S resulted in the activation of all three MAPK. In addition, mitochondrial activity was also significantly impaired at relatively low H(2)S concentrations. The transcription factor NF-kappaB is essential for the activation of most proinflammatory genes. However, the data presented imply that H(2)S activates proinflammatory genes in FLS through non-NF-kappaB-dependent pathways. Stress proteins reportedly act by blocking NF-kappaB activation, a mechanism that would explain the inability of stress proteins to prevent H(2)S mediated inflammatory processes. The presented data, showing MAPK activation, NF-kappaB-independent activation of a number of proinflammatory genes and mitochondrial damage, help to provide a better understanding of the biological and pathophysiological effects of exposure to H(2)S.

It is time to thoroughly study the effects of mild stress in rodents, but also in human beings

Many experiments on the effect of mild stress on aging have been done in invertebrates, but not in mammals. Using mild stress to improve healthspan seems to be possible, because the few studies on humans which have been published appear to be promising. Particularly, one may wonder whether heat shocks could be of some use in therapy or as an integrated part of daily life of elderly people. However, the top priority is probably to study more thoroughly the effects of mild stress in rodents, and not only in invertebrates.

Hyaluronan production in synoviocytes as a consequence of viral infections: HAS1 activation by Epstein-Barr virus and synthetic double- and single-stranded viral RNA analogs

One of the hallmarks of arthritis is swollen joints containing unusually high quantities of hyaluronan. Intact hyaluronan molecules facilitate cell migration by acting as ligands for CD44. Hyaluronan degradation products, readily formed at sites of inflammation, also fuel inflammatory processes. Irrespective of whether viruses could be a cause of rheumatoid arthritis, there is clear evidence that links viral infections to this debilitating disease. For this study, live Epstein-Barr virus and a number of double- and single-stranded synthetic viral analogs were tested for their effectiveness as activators of hyaluronan (HA) synthesis. As shown herein, Epstein-Barr virus-treated fibroblast-like synoviocytes significantly increase HA production and release. Real time reverse transcription-PCR data show that HAS1 mRNA levels are significantly elevated in virus-treated cells, whereas mRNA levels for the genes HAS2 and HAS3 remain unchanged. As to the mechanism of virus-induced HAS1 transcription, data are presented that imply that among the double- and single-stranded polynucleotides tested, homopolymeric polycytidylic structures are the most potent inducers of HAS1 transcription and HA release, whereas homopolymeric polyinosinic acid is without effect. Analyses of virus-induced signal cascades, utilizing chemical inhibitors of MAPK and overexpressing mutated IKK and IkappaB, revealed that the MAPK p38 as well as the transcription factor NF-kappaB are essential for virus-induced activation of HAS1. The presented data implicate HAS1 as the culprit in unfettered HA release and point out targets in virus-induced signaling pathways that might allow for specific interventions in cases of unwanted and uncontrolled HA synthesis.

Expression of heat shock protein receptors on fibroblast-like synovial cells derived from rheumatoid arthritis-affected joints

We examined the membrane expression of inducible Hsp70 and HSP receptors like TLR2, TLR4, CD14, CD36, CD40 and CD91 on fibroblast-like synovial cells (SC) derived from synovial tissue in 23 patients with rheumatoid arthritis (RA), who underwent synovectomy by using flow cytometric analysis. For comparison, autologous skin fibroblasts (SF) derived from the operation wound were tested. Significantly higher Hsp70 expression was found on synovial cells than on skin fibroblasts (median SC 21.4% x SF 5.0%, P < 0.001). Both synovial cells and skin fibroblasts expressed high levels of cell surface CD91 (median SC 80.2% x SF 79.2%), however, no or low levels of CD14, CD40, TLR2, TLR4 and CD36. Further, we observed high co-expression of CD91 and Hsp70 on RA synovial cells (median 18.6%), while skin fibroblasts showed only background Hsp70 expression (median 3.9%, P < 0.001). Since we demonstrated the high prevalence of inducible Hsp70 in RA synovial fluids, we speculate that Hsp70 might be captured onto the membrane of synovial cells from the extracellular space via the CD91 receptor. The significance of the Hsp70 interaction with synovial cells via CD91 remains undefined, but may mediate other non-immune purposes.