IL-1 in chronic arthritis, lessons from animal models

Mesenchymal Stem Cells and Myeloid-Derived Suppressor Cells Interplay in Adjuvant-Induced Arthritis Rat Model

There has not been much researchs on the biological relationship between myeloid-derived suppressor cells (MDSCs) and mesenchymal stem cells (MSCs). The goal of the current work is to examine how these cells cooperate with one another in a rat model of adjuvant-induced arthritis (AIA). Three groups of equal numbers of rats were created; the first group served as the control. Complete Freund's adjuvant (CFA) was injected into the second group to induce AIA. The third group underwent MSCstreatment. Three weeks later, ANA, IL-1β, IL-4, IL-6, IL-10, TNF-α, IFN-γ, M-CSF, iNOS and Arg-1 were determined using ELISA. Flowcytometric studies for MDSCs using CD11bc + and His48 + antibodies were performed. Current results showed significantly higher levels of WBCs, ANA, IL-1, IL-4, IL-6, IL-10, TNF-α, M-CSF, iNOS and Arg-1 along with a significant rise in MDSCs % in the AIA group compared to the control group. As opposed to AIA animals, MSCs administration resulted in a considerable improvement in cytokine levels, supporting the immunomodulation function of MSCs. Histological examination of the joints in the AIA group revealed articular cartilage degradation as well as infiltration of inflammatory cells and fibroplasia. These several evidences suggested that MDSCs may perform various roles in autoimmunity. Understanding how MDSCs and MSCs contribute to arthritis may help their prospective application in immunotherapy. Therefore, the reciprocal collaboration of MSCs and MDSCs must therefore be the subject of new investigations, which can offer new platforms for the development of more effective and individualized therapies for the treatment of immunological illnesses.

'Methyl palmitate attenuates adjuvant induced arthritis in rats by decrease of CD68 synovial macrophages

The study was designed to investigate the potential anti-arthritic effects of methyl palmitate in an adjuvant arthritis model in rats that shares many histopathological similarities with human RA. The underlying mechanism and its effect on CD68 macrophages were investigated, as a further argument to its possible efficacy in RA treatment. A normal control group was injected only with saline, arthritic group, and three treatment groups with CFA induced arthritis received methyl palmitate (MP) at three different doses (75, 150, 300 mg/kg/week for 3 weeks, intraperitoneal). The degree of ipsilateral paw swelling, ankle diameter, spleen index, thymus index and the expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β were measured. In addition, the underlying molecular mechanism was investigated using CD68 expression. Methyl palpitate significantly and dose dependently decreased the arthritic symptoms as measured by ipsilateral paw volume and ankle diameter. It showed no effect on body weight but significantly decreased splenic, thymus index, serum TNF-α and IL-1β. CD68 macrophages expression and the overall synovial inflammatory cellularity were halted. Methyl palmitate exhibits significant anti-inflammatory and exerts a potential anti-arthritic effect in a rat model of adjuvant induced arthritis. Furthermore, it inhibits expression of synovial CD68 macrophage that validate its therapeutic potential adjuvant arthritis.

A novel therapeutic approach targeting rheumatoid arthritis by combined administration of morin, a dietary flavanol and non-steroidal anti-inflammatory drug indomethacin with reference to pro-inflammatory cytokines, inflammatory enzymes, RANKL and transcription factors

The present study was designed to assess the combined efficacy of morin, a dietary flavanol and non-steroidal anti-inflammatory drug indomethacin against adjuvant-induced arthritis in rats, an experimental model for rheumatoid arthritis. Arthritis was induced by intradermal injection of complete freund's adjuvant (0.1 ml) into the right hind paw of the Wistar albino rats. Morin (30 mg/kg b.wt), indomethacin (3 mg/kg b.wt) and combination of morin and indomethacin were administered intraperitoneally (from 11th to 20th day) after adjuvant injection. We have found that the activities/levels of lysosomal acid hydrolases (acid phosphatase, β-galactosidase, N-acetyl glucosaminidase and cathepsin-D), glycoproteins (hexose and hexosamine), urinary constituents (hydroxyproline and glycosaminoglycans), reactive oxygen species (LPO and NO), elastase, inflammatory mediators (TNF-α, IL-1β, MCP-1, VEGF and PGE2) and paw edema were significantly increased in arthritic rats compared to controls. Whereas, the anti-oxidant status (SOD, CAT, GPx, glutathione, and ceruloplasmin), body weight and bone collagen was found to be decreased. The mRNA expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-17, IL-6 and MCP-1), inflammatory enzymes (iNOS and COX-2), RANKL, and transcription factors (NF-kB p65 and AP-1) was found upregulated in the ankle joints of arthritic rats in qRT-PCR analysis. In addition, the increased protein expression of NF-kB p65 and COX-2 was also detected by immunohistochemical analysis. On the other hand, the above said imbalances were regulated back effectively to near normal as evidenced by the histopathological and radiological analysis on combined treatment with morin and indomethacin. Our study indicates that the combination therapy was more effective than either single drug alone in suppressing the pathogenesis of RA.

Inhibition of interleukin-1beta converting enzyme (ICE or caspase 1) by aspartyl acyloxyalkyl ketones and aspartyl amidooxyalkyl ketones

A series of acyloxyalkyl and amidooxyalkyl ketones appended to a carbobenzyloxy aspartic acid core have been prepared. The most potent of these new inhibitors was 4i with a K(i) of 0.5 microM. These two series provide an improved understanding of the binding requirements for the hydrophobic prime side of ICE.

Succinic acid amides as P2-P3 replacements for inhibitors of interleukin-1beta converting enzyme (ICE or caspase 1)

Succinic acid amides have been found to be effective P2-P3 scaffold replacements for peptidic ICE inhibitors. Heteroarylalkyl fragments occupying the P4 position provided access to compounds with nM affinities. Utilization of an acylal prodrug moiety was required to overcome biopharmaceutical issues which led to the identification of 17f, a potential clinical candidate.