Huth Teilah Kathryn, Staines Donald, Marshall-Gradisnik Sonya
National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.
School of Medical Science, Griffith University, Southport, QLD, Australia.
J Transl Med. 2016 Apr 21;14:97. doi: 10.1186/s12967-016-0859-z.
Natural Killer (NK) cell effector functions are dependent on phosphorylation of the mitogen-activated protein kinases (MAPK) pathway to produce an effective immune response for the clearance of target cells infected with viruses, bacteria or malignantly transformed cells. Intracellular signals activating NK cell cytokine production and cytotoxic activity are propagated through protein phosphorylation of MAPKs including MEK1/2, ERK1/2, p38 and JNK. Reduced NK cell cytotoxic activity is consistently reported in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) patients and intracellular signalling by MAPK in NK cells remains to be investigated. Therefore, the purpose of this paper was to investigate MAPK downstream signalling molecules in NK cell phenotypes from CFS/ME patients.
Flow cytometric protocols were used to measure phosphorylation of the MAPK pathway in CD56(bright)CD16(dim/-) and CD56(dim)CD16(+) NK cells following stimulation with K562 tumour cells or phorbol-12-myristate-13-acetate plus ionomycin. NK cell cytotoxic activity, degranulation, lytic proteins and cytokine production were also measured as markers for CD56(bright)CD16(dim/-) and CD56(dim)CD16(+) NK cell function using flow cytometric protocols.
CFS/ME patients (n = 14) had a significant decrease in ERK1/2 in CD56(dim)CD16(+) NK cells compared to the non-fatigued controls (n = 11) after incubation with K562 cells. CD56(bright)CD16(dim/-) NK cells from CFS/ME patients had a significant increase in MEK1/2 and p38 following incubation with K562 cells.
This is the first study to report significant differences in MAPK intracellular signalling molecules in CD56(dim)CD16(+) and CD56(bright)CD16(dim/-) NK cells from CFS/ME patients. The current results highlight the importance of intracellular signalling through the MAPK pathway for synergistic effector function of CD56(dim)CD16(+) and CD56(bright)CD16(dim/-) NK cells to ensure efficient clearance of target cells. In CFS/ME patients, dysfunctional MAPK signalling may contribute to reduced NK cell cytotoxic activity.
自然杀伤（NK）细胞的效应功能依赖于丝裂原活化蛋白激酶（MAPK）途径的磷酸化，以产生有效的免疫反应来清除感染病毒、细菌的靶细胞或恶性转化细胞。激活NK细胞细胞因子产生和细胞毒性活性的细胞内信号通过包括MEK1/2、ERK1/2、p38和JNK在内的MAPK的蛋白质磷酸化进行传递。慢性疲劳综合征/肌痛性脑脊髓炎（CFS/ME）患者中NK细胞细胞毒性活性持续降低，NK细胞中MAPK的细胞内信号传导仍有待研究。因此，本文的目的是研究CFS/ME患者NK细胞表型中MAPK下游信号分子。
采用流式细胞术检测方案，在用K562肿瘤细胞或佛波醇-12-肉豆蔻酸酯-13-乙酸酯加离子霉素刺激后，测量CD56(bright)CD16(dim/-)和CD56(dim)CD16(+)NK细胞中MAPK途径的磷酸化。还使用流式细胞术检测方案测量NK细胞的细胞毒性活性、脱颗粒、裂解蛋白和细胞因子产生，作为CD56(bright)CD16(dim/-)和CD56(dim)CD16(+)NK细胞功能的标志物。
与非疲劳对照组（n = 1）相比，CFS/ME患者（n = 14）在与K562细胞孵育后，CD56(dim)CD16(+)NK细胞中的ERK1/2显著降低。CFS/ME患者的CD56(bright)CD16(dim/-)NK细胞在与K562细胞孵育后，MEK1/2和p38显著增加。
这是第一项报道CFS/ME患者CD56(dim)CD16(+)和CD56(bright)CD16(dim/-)NK细胞中MAPK细胞内信号分子存在显著差异的研究。目前的结果突出了通过MAPK途径进行细胞内信号传导对于CD56(dim)CD16(+)和CD56(bright)CD16(dim/-)NK细胞协同效应功能以确保有效清除靶细胞的重要性。在CFS/ME患者中，MAPK信号传导功能失调可能导致NK细胞细胞毒性活性降低。
