Interleukin (IL)-1 plays a key role in carcinogenesis, tumor progression, and metastasis. Although IL-1 may enhance the expansion of CD8+ T-cells, the pathological contribution of IL-1-activated CD8+ T-cells to tumor metastasis remains unclear. This study used a liver metastasis model of the EL4 T-cell lymphoma cells transplanted into human IL (hIL)-1α conditional transgenic (hIL-1α cTg) mice. Overproduction of hIL-1α suppressed both macroscopic and histological liver metastasis of EL4 T-cell lymphoma. The hIL-1α-induced inflammatory state increased the number of CD8+ T-cells both within and around metastatic tumors. Moreover, larger numbers of CD8+ T-cells showed greater infiltration of liver blood vessels in hIL-1α cTg mice than in control wild-type mice. Terminal deoxynucleotidyl transferase dUTP nick-end labeling staining of liver tissue from hIL-1α cTg mice indicated increased apoptosis of cells in the tumor. Localization of apoptosis cells resembled that of CD8+ T-cells. In addition, cytotoxicity assay showed that CD8+ T-cell counts from tumor-bearing hIL-1α cTg mice correlated with cytotoxicity against EL4. In summary, IL-1α suppresses lymphoma metastasis, and IL-1α-activated CD8+ T-cells may play important roles in inhibiting both tumor metastasis and metastatic tumor growth:

Background Mechanical overload applied on the articular cartilage may play an important role in the pathogenesis of osteoarthritis. However, the mechanism of chondrocyte mechanotransduction is not fully understood. The purpose of this study was to assess the effects of compressive mechanical stress on interleukin-1 receptor (IL-1R) and matrix-degrading enzyme expression by three-dimensional (3D) cultured ATDC5 cells. In addition, the implications of transient receptor potential vanilloid 4 (TRPV4) channel regulation in promoting effects of compressive mechanical loading were elucidated. Methods ATDC5 cells were cultured in alginate beads with the growth medium containing insulin-transferrin-selenium and BMP-2 for 6 days. The cultured cell pellet was seeded in collagen scaffolds to produce 3D-cultured constructs. Cyclic compressive loading was applied on the 3D-cultured constructs at 0.5 Hz for 3 h. The mRNA expressions of a disintegrin and metalloproteinases with thrombospondin motifs 4 (ADAMTS4) and IL-1R were determined with or without compressive loading, and effects of TRPV4 agonist/antagonist on mRNA expressions were examined. Immunoreactivities of reactive oxygen species (ROS), TRPV4 and IL-1R were assessed in 3D-cultured ATDC5 cells. Results In 3D-cultured ATDC5 cells, ROS was induced by cyclic compressive loading stress. The mRNA expression levels of ADAMTS4 and IL-1R were increased by cyclic compressive loading, which was mostly prevented by pyrollidine dithiocarbamate. Small amounts of IL-1β upregulated ADAMTS4 and IL-1R mRNA expressions only when combined with compressive loading. TRPV4 agonist suppressed ADAMTS4 and IL-1R mRNA levels induced by the compressive loading, whereas TRPV4 antagonist enhanced these levels. Immunoreactivities to TRPV4 and IL-1R significantly increased in constructs with cyclic compressive loading. Conclusion Cyclic compressive loading induced mRNA expressions of ADAMTS4 and IL-1R through reactive oxygen species. TRPV4 regulated these mRNA expressions, but excessive compressive loading may impair TRPV4 regulation. These findings suggested that TRPV4 regulates the expression level of IL-1R and subsequent IL-1 signaling induced by cyclic compressive loading and participates in cartilage homeostasis.

Purpose: Mechanical overload applied on the articular cartilage may play an important role in the pathogenesis of osteoarthritis. However, the mechanism of chondrocyte mechanotransduction is not fully understood. Previous study showed that IL-1b released from OA cartilage and the downstream effectors of IL-1b contributed to osteoarthritis progression. Transient Receptor Potential Vanilloid 4 (TRPV4) is a calcium-permeable membrane cation channel that plays a critical regulatory role in the development and maintenance of articular cartilage. We hypothesized that the expression of the IL-1 receptor 1 (IL-1R1) on the surface of chondrocytes would be stimulated by compressive mechanical stress, and subsequent increment of IL-1 susceptibility would be implicated in the OA pathology. We successfully made a three-dimensional (3D) cartilage constructs and maintained it in a cyclic load bioreactor in order to examine chondrocyte responses to the mechanical stress. The purpose of this study was to analyze mechanical stress-induced IL-1R1 expression in 3D-cultured chondrocytes, and the effects of TRPV4 channel regulation on IL-1R1 expression. Methods: Mouse embryonal carcinoma-derived clonal cell line (ATDC5 cells) was cultured in alginate beads with the growth medium for 6 days. The cells were seeded within collagen gels and type-I collagen scaffold, which enabled ATDC5 cells to maintain chondrogenic phenotype in 3D environment. Histologically, chondrocytes presented with round shape, and mostly synthesized cartilage matrix. The mRNA expression of type-II collagen was enhanced by addition of BMP-2 (Fig.1). Cyclic compressive loading of 40 kPa at 0.5Hz was applied to the 3D cartilage constructs using a cyclic load bioreactor for 3 hours. Thereafter, ADAMTS4 and IL-1R1 mRNA expressions were measured in real-time PCR 6 hours after the cyclic loading. The effects of subtle amount of IL-1b (1pg/ml) was determined with or without compressive stress, and the effects of TRPV4 agonist/antagonist on IL-1-induced ADAMTS4 and MMP3 were determined. Experimental OA was made in IL-1 receptor knockout mice and wild type mice as controls, using techniques of destabilization of the medial meniscus (DMM). OA progression in knee joints was evaluated with Osteoarthritis Research Society International (OARSI) score at 8 weeks postoperatively. Results: The mRNA levels of ADAMTS4 and IL-1R1 were substantially increased by the excessive compressive stress. Compressive stress plus IL-1b (1pg/ml) upregulated ADAMTS4 and IL-1R1 expressions by 3-fold and 8-fold, respectively, but IL-1b alone failed to do so (Fig.2). TRPV4 agonist suppressed upregulation of ADAMTS4 and IL-1R1 mRNA levels by cyclic compressive stress, conversely, TRPV4 antagonist rather accelerated these mRNA expressions (Fig.3). IL-1 receptor knockout mice exhibited reduced cartilage degradation in DMM-induced experimental OA (Fig.4). Conclusions: The present study introduced the compressive stress which may more closely mimic physiological condition of articular joint. ATDC5 cells wer...