Binsaleh Naif K, Eltayeb Reem, Qanash Husam, Aziz Mohammad Azhar, Albaradie Raid, Khan Mohd Wajid Ali
Department of Medical Laboratory Science, College of Applied Medical Sciences, University of Ha'il, Ha'il, Saudi Arabia.
Molecular Diagnostics and Personalized Therapeutics Unit, University of Ha'il, Ha'il, Saudi Arabia.
Front Genet. 2022 May 25;13:909903. doi: 10.3389/fgene.2022.909903. eCollection 2022.
Lymphoma is a chronic inflammatory disease in which the immune system is highly affected. Increased oxidative stress is one of the common conditions of cancer and affects macromolecules. Histone modifications affect the chromatin structure and functions. In this study, histone H1 (His-H1) protein was modified by reactive oxygen species (ROS), and structural and chemical changes were studied. Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) patients were selected, and oxidative stress markers, inflammatory cytokines, and serum autoantibodies were analyzed using biochemical and immunological assays. Furthermore, the formation of antigen-antibody immune complexes was assessed by the Langmuir plot. ROS-modified His-H1 (ROS-His-H1) showed substantial structural perturbation in protein (UV-hyperchromicity and increased intrinsic fluorescence) compared to the native His-H1 protein. A possible explanation for the changes is suggested by the exposure of the aromatic chromophore to the solvent. In-depth structural analysis by circular dichroism (CD) exhibited major changes in α-helix (-21.43%) and turns (+33%), reflecting changes in the secondary structure of histone H1 protein after ROS exposure. ELISA and competitive ELISA findings revealed high recognitions of serum autoantibodies to ROS-His-H1 from NHL, followed by HL subjects. Healthy controls showed negligible binding. Non-modified His-H1 did not show any binding with serum samples from either cohort. High apparent association constants (ACCs) were calculated for ROS-His-H1 using purified IgGs from NHL (1.46 × 10 M) compared to HL (1.33 × 10 M) patients. Non-modified His-H1 exhibited a hundred times less ACC for NHL (2.38 × 10 M) and HL (2.46 × 10 M) patients. Thus, ROS modifications of histone H1 cause structural changes and expose cryptic neo-epitopes on the protein against which autoantibodies were generated. These perturbations might affect the histone DNA interaction dynamics and potentially be correlated with gene dysregulation. These subtle molecular changes with an immune imbalance might further aggravate the disease.
淋巴瘤是一种慢性炎症性疾病，其中免疫系统受到高度影响。氧化应激增加是癌症的常见情况之一，会影响大分子。组蛋白修饰会影响染色质结构和功能。在本研究中，组蛋白H1（His-H1）蛋白被活性氧（ROS）修饰，并对其结构和化学变化进行了研究。选取了霍奇金淋巴瘤（HL）和非霍奇金淋巴瘤（NHL）患者，使用生化和免疫测定法分析了氧化应激标志物、炎性细胞因子和血清自身抗体。此外，通过朗缪尔图评估抗原-抗体免疫复合物的形成。与天然His-H1蛋白相比，ROS修饰的His-H1（ROS-His-H1）在蛋白质中表现出显著的结构扰动（紫外增色和固有荧光增加）。芳香发色团暴露于溶剂中为这些变化提供了一种可能的解释。通过圆二色性（CD）进行的深入结构分析显示α-螺旋（-21.43%）和转角（+33%）发生了重大变化，反映了ROS暴露后组蛋白H1蛋白二级结构的变化。酶联免疫吸附测定（ELISA）和竞争性ELISA结果显示，NHL患者血清自身抗体对ROS-His-H1的识别率很高，其次是HL患者。健康对照显示结合可忽略不计。未修饰的His-H1与两个队列的血清样本均未显示任何结合。与HL患者（1.33×10⁻⁷M）相比，使用来自NHL患者的纯化免疫球蛋白（IgG）计算出ROS-His-H1的表观缔合常数（ACC）很高（1.46×10⁻⁷M）。未修饰的His-H1对NHL患者（2.38×10⁻⁹M）和HL患者（2.46×10⁻⁹M）的ACC低一百倍。因此，组蛋白H1的ROS修饰会导致结构变化，并在蛋白质上暴露隐蔽的新表位，从而产生自身抗体。这些扰动可能会影响组蛋白与DNA的相互作用动力学，并可能与基因失调相关。这些伴有免疫失衡的细微分子变化可能会进一步加重疾病。
