Chemical Hypoxia Brings to Light Altered Autocrine Sphingosine-1-Phosphate Signalling in Rheumatoid Arthritis Synovial Fibroblasts

Figure 4

Differential expression of SGPP1 and SPL in normal FLS and RAFLS. Human primary FLS from normal () and RA () donors were incubated with or without 200 μM CoCl₂ for 24 h. Total RNA was extracted for quantitative PCR analyses and RPLP0 was used as an internal control and data normalized to that of normal FLS (a). The data are the means ± SE from four experiments (4 different donors) performed in triplicate (3 independent experiments). For statistical analyses, we compared the cells stimulated with CoCl₂ to those without CoCl₂, or normal FLS to RAFLS. ; ; . Human primary FLS from RA patients () were incubated with 200 μM CoCl₂ for up to 48 h (b). Proteins from whole cell lysates were prepared for Western blot. Total PI3-kinase p85 subunit was used as a control for protein loading. Data presented are from a representative blot (upper panel) or the means ± SE from three experiments (lower panel). For statistical comparative analyses, the samples stimulated with CoCl₂ at 0 h were compared to those treated for indicated times. .

(a)

(b)