Matrix metalloproteinase-3 (MMP-3) plays an important role in intervertebral disc degeneration, a ubiquitous condition closely linked to low back pain and disability. Elevated expression of syndecan 4, a cell surface heparan sulfate proteoglycan, actively controls disc matrix catabolism. However, the relationship between MMP-3 expression and syndecan 4 in the context of inflammatory disc disease has not been clearly defined. We investigated the mechanisms by which cytokines control MMP-3 expression in rat and human nucleus pulposus cells. Cytokine treatment increased MMP-3 expression and promoter activity. Stable silencing of syndecan 4 blocked cytokine-mediated MMP-3 expression; more important, syndecan 4 did not mediate its effects through NF-κB or mitogen-activated protein kinase (MAPK) pathways. However, treatment with MAPK and NF-κB inhibitors resulted in partial blocking of the inductive effect of cytokines on MMP-3 expression. Loss-of-function studies confirmed that NF-κB, p38α/β2/γ/δ, and extracellular signal-regulated kinase (ERK) 2, but not ERK1, contributed to cytokine-dependent induction of MMP3 promoter activity. Similarly, inhibitor treatments, lentiviral short hairpin-p65, and short hairpin-IκB kinase β significantly decreased cytokine-dependent up-regulation in MMP-3 expression. Finally, we show that transforming growth factor-β can block the up-regulation of MMP-3 induced by tumor necrosis factor (TNF)-α by counteracting the NF-κB pathway and syndecan 4 expression. Taken together, our results suggest that cooperative signaling through syndecan 4 and the TNF receptor 1-MAPK-NF-κB axis is required for TNF-α-dependent expression of MMP-3 in nucleus pulposus cells. Controlling these pathways may slow the progression of intervertebral disc degeneration and matrix catabolism.
Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome is a rare plasma dyscrasia without standard treatment. This phase II prospective trial evaluates the safety and response of 12 cycles of low dose lenalidomide (10 mg) plus dexamethasone (Rdex) in patients with newly diagnosed POEMS syndrome. Forty-one patients (28 men) were enrolled and the median age at diagnosis was 49 years (range, 21-70 years). Twenty-one patients (46%) achieved complete hematologic response and the neurologic response rate was 95%. The median serum vascular endothelial growth factor (VEGF) declined from 5155 pg/mL (range, 534-14 328 pg/mL) to 832 pg/mL (95-6254 pg/mL) after therapy. The overall VEGF response rate was 83%, and the median time to response was 2 months, with a mean VEGF reduction of 43% at the first month. In terms of clinical response, Rdex substantially relieved extravascular volume overload, organomegaly, and pulmonary hypertension. No treatment-related deaths occurred and no patients suffered from lenalidomide-related grade 3 or above adverse events. After a median follow-up of 34 months, median overall survival (OS) and progression-free survival (PFS) were not reached, with an estimated 3-year OS and PFS of 90% and 75%, respectively. In conclusion, Rdex was active with high hematologic, VEGF and organ response rate and well tolerated for patients with newly diagnosed POEMS syndrome. This trial was registered at www.clinicaltrials.gov as #NCT01816620.
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