Mesenchymal Stromal Cell Conditioning by Carbon Monoxide

项目总结(见说明)： 脓毒症是一种疾病过程，代表全身对严重感染的反应。感染性损伤会激活宿主的免疫细胞，包括中性粒细胞、单核/巨噬细胞和淋巴细胞。免疫细胞的早期激活会触发促炎反应，从而有助于根除入侵的微生物(S)。如果病原体不被根除，脓毒症可能发展为严重的脓毒症(脓毒症合并器官功能障碍，如肺损伤和呼吸衰竭)和感染性休克(严重的脓毒症 加上顽固性低血压和循环衰竭)，这往往会导致死亡。一旦入侵的微生物(S)被根除，免疫反应的解决就至关重要，因为持续的全身炎症将导致器官损伤。不幸的是，这种早期的促炎反应也可能伴随着免疫麻痹的后期状态，部分原因是免疫效应细胞的凋亡。脓毒症期间发生的一连串生物事件是复杂的，治疗策略需要根据诊断时的脓毒症阶段量身定做。多潜能间充质基质细胞(MSCs)被认为是一种很有前途的细胞治疗平台。已知间充质干细胞具有免疫调节作用 最近有研究表明，骨髓间充质干细胞在小鼠盲肠结扎和穿孔的早期促炎阶段是有益的。我们假设，当MSCs在多菌或单菌败血症发病后应用于小鼠时，将适应脓毒症的特定阶段，并导致改善结局。我们实验室先前的研究表明，血红素加氧酶(H0)-1衍生的一氧化碳(CO)是一种已知的抗炎分子，在脓毒症过程中也具有抗微生物特性。因此，我们还假设，在体内用CO处理MSCs可以改善其体内功能，并增加MSCs在小鼠脓毒症发病后的益处。深入了解一氧化碳条件下骨髓间充质干细胞增强反应的机制将使我们进一步了解作为一种基于细胞的治疗方法的骨髓间充质干细胞，并为这一毁灭性的疾病过程开发新的治疗策略。在拥有“人性化”免疫系统的小鼠身上，也将对MSCs的CO调节进行研究。 最后，我们将通过评估脓毒症或脓毒症合并急性肺损伤患者的中性粒细胞和单核细胞的吞噬功能来促进对脓毒症的人类免疫反应的理解，并与对照组的细胞进行比较。我们将确定体外给予MSCs？CO是否能改善吞噬细胞功能。这些功能分析将与患者的预后相关。

PROJECT SUMMARY (See instmctions): Sepsis is a disease process representing the systemic response to severe infection. The infectious insult activates immune cells of the host, including neutrophils, monocytes/macrophages, and lymphocytes. Early activation of immune cells triggers a pro-inflammatory response that contributes to eradication of the invading microorganism(s). If the pathogens are not eradicated, sepsis may progress to severe sepsis (sepsis plus organ dysfunction, such as lung injury and respiratory failure) and septic shock (severe sepsis plus refractory hypotension and circulatory failure), which frequently leads to death. Once the invading microorganism(s) are eradicated, then resolution of the immune response is critical, as continued systemic inflammation will lead to organ injury. Unfortunately, this early pro-inflammatory response may also be followed by a later state of immunoparalysis, due in part to apoptosis of immune effector cells. The cascade of biologic events that occur during sepsis is complex, and therapeutic strategies need to be tailored depending upon the stage of sepsis at the time of diagnosis. Multipotent mesenchymal stromal cells (MSCs) are considered to be a promising platform for cell-based therapy. MSCs are known to have immunomodulatory properties, and recently it has been suggested that MSCs are beneficial during the early proinflammatory stage of cecal ligation and puncture in mice. We hypothesize that MSCs, when administered to mice after the onset of polymicrobial or single organism sepsis, will adapt to the specific stage of sepsis and lead to an improved outcome. Prior studies in our laboratory demonstrated that heme oxygenase (H0)-1-derived carbon monoxide (CO), a known anti-inflammatory molecule, also has anti-microbial properties during sepsis. Thus, we also hypothesize that conditioning MSCs with CO ex vivo will improve their function In vivo, and increase the beneficial effects of MSCs after the onset of sepsis in mice. Gaining insight into the mechanisms responsible for this enhanced response of MSCs conditioned with CO will allow us to further understand MSCs as a cell-based therapy, and to develop novel therapeutic strategies for this devastating disease process. MSCs ¿ CO conditioning will also be studied in mice with a "humanized" immune system. Finally we will advance the understanding of the human immune response to sepsis by assessing phagocytic function of neutrophils and monocytes harvested from patients with sepsis or sepsis plus acute lung injury, compared with cells from control patients. We will determine whether the administration of MSCs ¿ CO ex vivo can improve phagocyte function. These functional assays will be correlated with patient outcome.