Campisi Jay, Leem Ted H, Fleshner Monika
Department of Integrative Physiology, University of Colorado, Boulder, CO 80309-0354, USA.
Cell Stress Chaperones. 2003 Fall;8(3):272-86. doi: 10.1379/1466-1268(2003)008<0272:sehiaf>2.0.co;2.
Extracellular heat-shock proteins (eHsp) such as those belonging to the 70-kDa family of Hsp (eg, Hsp72) have been hypothesized to act as a "danger signal" to immune cells, promote immune responses, and improve host defense. The current study tested this hypothesis. Adult male F344 rats were exposed to an acute laboratory stressor (100, 5-second, 1.6-mA inescapable tail shocks) and challenged with Escherichia coli. The number of colony-forming units (CFU) of bacteria at the site of injection, the levels of eHsp72, the immune response to eHsp72 and E. coli-derived lipopolysaccharide (LPS), and the amount of time required to recover from in vivo bacterial challenge were measured. CFUs were reduced 2, 4, and 6 hours after injection of E. coli in rats exposed to stress. Rats exposed to stress had elevated eHsp72 that was elevated rapidly (25 minutes) and remained elevated in the circulation and at the inflammatory site (2 hours after stressor termination). Both stressor exposure and eHsp72 administration in the absence of stress resulted in a facilitated pattern of recovery after bacterial inflammation induced by subcutaneous E. coli injection. Rats exposed to acute restraint (100 minutes) did not demonstrate elevated circulating eHsp72 or a facilitated pattern of recovery after bacterial challenge. In vitro stimulation of rat splenocytes and macrophages with eHsp72 elevated nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-1beta, and IL-6, and this effect was specific to eHsp72 because it was not diminished by polymyxin B and was reduced by earlier heat-denature treatment. Stimulation of cells with eHsp72 combined with LPS resulted in a greater NO and cytokine response than that observed after stimulation with eHsp72 or LPS alone. In vivo, at the inflammatory site, the bacterial-induced NO response was potentiated by stress, and NO inhibition (L-NIO) reduced the stress-induced facilitation but had no effect on the control kinetics of bacterial inflammation recovery. Thus, these results lend support to the hypothesis that intense stressor exposure increases eHsp72, which acts as a danger signal to potentiate the NO response to bacterial challenge and facilitate recovery from bacterial inflammation.
细胞外热休克蛋白（eHsp），如属于70 kDa热休克蛋白家族的那些蛋白（例如Hsp72），被假定可作为免疫细胞的“危险信号”，促进免疫反应并改善宿主防御。本研究对这一假设进行了验证。成年雄性F344大鼠暴露于急性实验室应激源（100次、每次5秒、1.6毫安不可逃避的尾部电击），然后用大肠杆菌进行攻击。测量注射部位细菌的菌落形成单位（CFU）数量、eHsp72水平、对eHsp72和大肠杆菌衍生脂多糖（LPS）的免疫反应，以及从体内细菌攻击中恢复所需的时间。在暴露于应激的大鼠中，注射大肠杆菌后2、4和6小时CFU减少。暴露于应激的大鼠eHsp72升高，其迅速升高（25分钟），并在循环系统和炎症部位保持升高（应激源终止后2小时）。应激源暴露和在无应激情况下给予eHsp72均导致皮下注射大肠杆菌诱导的细菌性炎症后恢复模式加快。暴露于急性束缚（100分钟）的大鼠在细菌攻击后未表现出循环eHsp72升高或恢复模式加快。用eHsp72体外刺激大鼠脾细胞和巨噬细胞可提高一氧化氮（NO）、肿瘤坏死因子α（TNF-α）、白细胞介素（IL）-1β和IL-6水平，且这种效应是eHsp72特有的，因为它不会被多粘菌素B减弱，而早期热变性处理可使其降低。用eHsp72与LPS联合刺激细胞比单独用eHsp72或LPS刺激后观察到更大的NO和细胞因子反应。在体内，在炎症部位，应激增强了细菌诱导的NO反应，NO抑制（L-NIO）降低了应激诱导的促进作用，但对细菌性炎症恢复的对照动力学无影响。因此，这些结果支持了以下假设：强烈的应激源暴露会增加eHsp72，其作为危险信号增强对细菌攻击的NO反应并促进从细菌性炎症中恢复。
