Rheumatoid arthritis (RA) is a chronic, systemic autoimmune inflammatory and debilitating disease that involves the systemic imbalance of the immune network. Previous studies have shown that acupuncture can help treat RA. However, its specific mechanisms are not fully understood. Thus, the present study was designed to clarify the mechanisms of acupuncture acted on RA via immune network modulation using complete Freund's adjuvant (CFA)-induced arthritic rats. Results revealed that manual acupuncture (MA) could alleviate the inflammation and pain of infected joints. Moreover, MA could effectively stimulate the innate immune cytokines (IL-1[Formula: see text], IL-1[Formula: see text], IL-6, IL-7, IL-18, TNF-[Formula: see text]) and adaptive immunity cytokines (IL-2, IL-12, IFN-[Formula: see text], IL-4, IL-5, IL-10, IL-13, IL-17) as the main part of the immune response and repaired damage of RA. These complex immunomodulatory processes were analyzed quantitatively by cell-cell communication (CCC) networks. The CCC networks demonstrated that the immune networks were enhanced with the development of RA, while MA enhanced the immune networks in the early stage to act on RA and promoted the immune-network to a normal level at the late stage. Moreover, we found that monocyte/macrophage and endothelial cells were the key cells of innate immunity and body cells; T1, T2 and B cells were the key cells of adaptive immunity, which were also the main target cells for MA regulation.

The ubiquitin system is important for drug discovery, and the discovery of selective small-molecule inhibitors of deubiquitinating enzymes (DUBs) remains an active yet extremely challenging task. With a few exceptions, previously developed inhibitors have been found to bind the evolutionarily conserved catalytic centers of DUBs, resulting in poor selectivity. The small molecule IU1 was the first-ever specific inhibitor identified and exhibited surprisingly excellent selectivity for USP14 over other DUBs. However, the molecular mechanism for this selectivity was elusive. Herein, we report the high-resolution co-crystal structures of the catalytic domain of USP14 bound to IU1 and three IU1 derivatives. All the structures of these complexes indicate that IU1 and its analogs bind to a previously unknown steric binding site in USP14, thus blocking the access of the C-terminus of ubiquitin to the active site of USP14 and abrogating USP14 activity. Importantly, this steric site in USP14 is very unique, as suggested by structural alignments of USP14 with several known DUB X-ray structures. These results, in conjunction with biochemical characterization, indicate a coherent steric blockade mechanism for USP14 inhibition by compounds of the IU series. In light of the recent report of steric blockade of USP7 by FT671, this work suggests a potential generally applicable allosteric mechanism for the regulation of DUBs via steric blockade, as showcased by our discovery of IU1-248 which is 10-fold more potent than IU1.

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BackgroundThe runt-related transcription factor 2 (Runx2) is a cell-fate-determining factor that controls osteoblast differentiation and bone formation. It has been previously demonstrated that microRNAs (miRNAs) play important roles in osteogenesis. However, the Runx2-regulated miRNAs that have been reported thus far are limited. In this study, we pursued to identify these miRNAs in Tet-on stable C2C12 cell line (C2C12/Runx2Dox subline).ResultsMicroarray analysis revealed that alterations in miRNA expression occur with 54 miRNAs. Among these miRNAs, miR-690 was identified as a positive regulator of Runx2-induced osteogenic differentiation of C2C12 cells through gain- and loss-of-function assays. Expression of miR-690 is induced by Runx2, which binds directly to the putative promoter of mir-690 (Mirn690). The miR-690 proceeds to inhibit translation of the messenger RNA encoding the nuclear factor kappa B (NF-κB) subunit p65 whose overexpression inhibits Runx2-induced osteogenic differentiation of C2C12 cells. Interleukin-6 (IL-6), a downstream target of NF-κB pathway, is upregulated by p65 overexpression but significantly downregulated during this differentiation process. Furthermore, overexpression of IL-6 impedes the expression of osteocalcin, a defined marker of late osteoblast differentiation.ConclusionsTogether, our results suggest that the miR-690 transactivated by Runx2 acts as a positive regulator of Runx2-induced osteogenic differentiation by inactivating the NF-κB pathway via the downregulation of the subunit p65.Electronic supplementary materialThe online version of this article (doi:10.1186/s13578-016-0073-y) contains supplementary material, which is available to authorized users.