Human Synoviocytes

The recombinant vesicular stomatitis virus–vectored Zaire Ebola virus glycoprotein (rVSVΔG-ZEBOV-GP) vaccine, while effective and well-tolerated, exhibits notable reac... More

The recombinant vesicular stomatitis virus–vectored Zaire Ebola virus glycoprotein (rVSVΔG-ZEBOV-GP) vaccine, while effective and well-tolerated, exhibits notable reactogenicity, manifesting in expected adverse events (AEs), such as fever, headache, and pain, along with rare, unexpected AEs, including skin lesions, cutaneous vasculitis, and transient arthritis. The presence or absence of AEs following rVSVΔG-ZEBOV-GP vaccination is associated with a specific innate plasma signature. This study aims to elucidate in vitro the tropism of the vaccine for different cell types derived from tissues previously reported to be involved in the unexpected AEs. Upon in vitro infection with rVSVΔG-ZEBOV-GP, various cell types, such as synoviocytes, fibroblasts, keratinocytes, and endothelial cells (except chondrocytes), demonstrate productive infection, which in dermal fibroblasts triggered the release of many innate plasma signature markers, including keratinocytes’ pro-inflammatory and proapoptotic cytokines such as OSM and TRAIL. Infected monocytes from buffy coats, activated by infection, produce most innate plasma signature markers. In co-culture, rVSVΔG-ZEBOV-GP-infected monocytes serve as a source to synoviocyte infection, resulting in distinct kinetics modulation in innate biomarkers (transcription and secretion) and upregulation of specific genes, such as NEDD8 and SIGLEC-1, which have been associated with inflammatory arthritis in animal models. Altogether, our work, based on in vitro studies, provides insights into the possible mechanisms of rVSVΔG-ZEBOV-GP underlying the observed reactogenicity by showing tropism of the vaccine for off-target cells derived from AE-affected compartments (skin, joints, vessels). Furthermore, in vitro interaction with infected monocytes modulates the innate response of synoviocytes. Less

Aims: The severity of cartilage degeneration is positively correlated with the severity of the pathologic change of medial plica. However, knowledge of the pathogenic mec... More

Aims: The severity of cartilage degeneration is positively correlated with the severity of the pathologic change of medial plica. However, knowledge of the pathogenic mechanisms and the impact of plica on cartilage destruction is limited. The aim of the present study was therefore to investigate matrix metalloprotease-3 (MMP-3) expression in the plica isolated from patients with medial compartment osteoarthritis of the knee. Methods and results: Immunohistochemistry showed that MMP-3 was highly expressed in pannus-like tissue and the plica. Western blotting of culture supernatants showed that interleukin-1β (IL-1β) treatment induced MMP-3 release by cells isolated from pannus tissue or the plica. Furthermore, reverse transcriptase polymerase chain reaction and real-time polymerase chain reaction analysis showed that MMP-3 mRNA levels were increased after IL-1β treatment of the cultured cells. MMP-3 and IL-1β mRNAs were expressed in the plica and pannus-like tissue, with MMP-3 mRNA being expressed at significantly higher levels in the plica than in normal synovial membrane and highly expressed in the plica at different stages in osteoarthritis (OA) patients. Conclusion: Pannus-like tissue and the plica express IL-1β and MMP-3. Moreover, MMP-3 mRNA and protein expression in the plica may contribute to the pathogenesis of OA. © 2011 Blackwell Publishing Limited. Less

Lipopolysaccharide (LPS)/Toll-like receptor 4 (TLR4)-mediated signaling pathways have caught the attention of strategies designed for rheumatoid arthritis (RA). In this s... More

Lipopolysaccharide (LPS)/Toll-like receptor 4 (TLR4)-mediated signaling pathways have caught the attention of strategies designed for rheumatoid arthritis (RA). In this study, we identified that cPLA(2)alpha acted as a modulator of LPS-induced VCAM-1 expression and THP-1 (human acute monocytic leukemia cell line) adherence. Treatment of RA synovial fibroblasts (RASFs) with LPS, a TLR4 agonist, promoted the VCAM-1 expression and THP-1 adherence which were decreased by pretreatment with a selective cytosolic phospholipase A(2) (cPLA(2)) inhibitor (AACOCF(3)), implying the involvement of cPLA(2)alpha in these responses. This notion was further confirmed by knockdown of cPLA(2)alpha expression by transfection with cPLA(2)alpha small interfering RNA (siRNA) leading to a decrease in VCAM-1 expression and THP-1 adherence induced by LPS. Subsequently, the LPS-stimulated cPLA(2)alpha phosphorylation was attenuated by pretreatment with a MEK1/2 inhibitor (U0126), suggesting that LPS-stimulated cPLA(2)alpha phosphorylation and activity are mediated through an ERK-dependent mechanism. Moreover, COX-2-derived PGE(2) production appeared to involve in LPS-induced VCAM-1 expression which was attenuated by pretreatment with selective COX-2 inhibitors (NS-398 and celecoxib), transfection with COX-2 siRNA, or PGE(2) receptor antagonists. In addition, pretreatment with ecosapentaenoic acid (EPA), a substrate competitor of arachidonic acid (AA), also blocked LPS-induced VCAM-1 mRNA and protein expression, and THP-1 adherence. Collectively, these results suggest that LPS-induced VCAM-1 expression and adhesion of THP-1 cells are mediated through the TLR4/ERK/cPLA(2)alpha phosphorylation and COX-2 expression/PGE(2) synthesis in RASFs. Less

The primary cilium is a non-motile microtubule-based structure that shares many similarities with the structures of flagella and motile cilia. It is well known that the l... More

The primary cilium is a non-motile microtubule-based structure that shares many similarities with the structures of flagella and motile cilia. It is well known that the length of flagella is under stringent control, but it is not known whether this is true for primary cilia. In this study, we found that the length of primary cilia in fibroblast-like synoviocytes, either in log phase culture or in quiescent state, was confined within a range. However, when lithium was added to the culture to a final concentration of 100 mM, primary cilia of synoviocytes grew beyond this range, elongating to a length that was on average approximately 3 times the length of untreated cilia. Lithium is a drug approved for treating bipolar disorder. We dissected the molecular targets of this drug, and observed that inhibition of adenylate cyclase III (ACIII) by specific inhibitors mimicked the effects of lithium on primary cilium elongation. Inhibition of GSK-3beta by four different inhibitors did not induce primary cilia elongation. ACIII was found in primary cilia of a variety of cell types, and lithium treatment of these cell types led to their cilium elongation. Further, we demonstrate that different cell types displayed distinct sensitivities to the lithium treatment. However, in all cases examined primary cilia elongated as a result of lithium treatment. In particular, two neuronal cell types, rat PC-12 adrenal medulla cells and human astrocytes, developed long primary cilia when lithium was used at or close to the therapeutic relevant concentration (1-2 mM). These results suggest that the length of primary cilia is controlled, at least in part, by the ACIII-cAMP signaling pathway. Less