Exposure to workplace bullying, microRNAs and pain; evidence of a moderating effect of miR-30c rs928508 and miR-223 rs3848900

Prolonged exposure to bullying behaviors may give rise to symptoms such as anxiety, depression and chronic pain. Earlier data suggest that these symptoms often are associated with stress-induced low-grade systemic inflammation. Here, using data from both animals and humans, we examined the moderating role of microRNAs (miRNAs, miRs) in this process. In the present study, a resident-intruder paradigm, blood samples, tissue harvesting and subsequent qPCR analyses were used to screen for stress-induced changes in circulating miRNAs in rats. The negative acts questionnaire (NAQ), TaqMan assays and a numeric rating scale (NRS) for pain intensity were then used to examine the associations among bullying behaviors, relevant miRNA polymorphisms and pain in a probability sample of 996 Norwegian employees. In rats, inhibited weight gain, reduced pituitary POMC expression, adrenal Nr3c1 mRNA downregulation, as well as increased miR-146a, miR-30c and miR-223 in plasma were observed following 1 week of repeated exposure to social stress. When following up the miRNA findings from the animal study in the human working population, a stronger relationship between NAQ and NRS scores was observed in subjects with the miR-30c GG genotype (rs928508) compared to other subjects. A stronger relationship between NAQ and NRS scores was also seen in men with the miR-223 G genotype (rs3848900) as compared to other men. Our findings show that social stress may induce many physiological changes including changed expression of miRNAs. We conclude that the miR-30c GG genotype in men and women, and the miR-223 G genotype in men, amplify the association between exposure to bullying behaviors and pain.Lay summaryUsing an animal model of social stress, we identified miR-146a, miR-30c and miR-223 as potentially important gene regulatory molecules that may be involved in the stress response. Interestingly, human genotypes affecting the expression of mature miR-30c and miR-223 had a moderating effect on the association between exposure to bullying and pain. Subjects with the miR-30c rs928508 GG genotype had a significantly stronger association between exposure to bullying behaviors and pain than other subjects. The same was observed in men with the miR-223 rs3848900 G genotype, as compared to other men. Using an animal model of social stress, we identified miR-146a, miR-30c and miR-223 as potentially important gene regulatory molecules that may be involved in the stress response. Interestingly, human genotypes affecting the expression of mature miR-30c and miR-223 had a moderating effect on the association between exposure to bullying and pain. Subjects with the miR-30c rs928508 GG genotype had a significantly stronger association between exposure to bullying behaviors and pain than other subjects. The same was observed in men with the miR-223 rs3848900 G genotype, as compared to other men.

长期暴露于欺凌行为可能引发焦虑、抑郁及慢性疼痛等症状。既往研究数据表明，此类症状常与应激诱导的轻度全身性炎症相关。本研究借助动物与人类两类数据，探究微小RNA（microRNAs, miRNAs, miRs）在该过程中的调节作用。

本研究首先采用居住者-侵入者范式（resident-intruder paradigm）、血液样本采集、组织取材及后续实时定量聚合酶链反应（qPCR）分析，筛选大鼠循环微小RNA的应激诱导表达变化。随后，通过负面行为问卷（negative acts questionnaire, NAQ）、TaqMan检测法（TaqMan assays）及疼痛强度数字评分量表（numeric rating scale, NRS），对996名挪威雇员的概率样本展开分析，以检验欺凌行为、相关微小RNA多态性与疼痛之间的关联。

在大鼠模型中，经1周反复社交应激暴露后，观察到体重增长受抑、垂体前阿黑皮素原（POMC）表达下调、肾上腺Nr3c1信使RNA（mRNA）表达降低，同时血浆中miR-146a、miR-30c及miR-223水平升高。

在人类职场人群中验证动物研究的微小RNA发现时，相较于其他受试者，携带miR-30c GG基因型（rs928508）的群体中，负面行为问卷（NAQ）得分与疼痛强度数字评分量表（NRS）得分之间的关联更强。同样，相较于其他男性群体，携带miR-223 G基因型（rs3848900）的男性群体中，NAQ得分与NRS得分之间的关联也更为显著。

本研究结果表明，社交应激可诱发多种生理变化，包括微小RNA的表达改变。我们认为，男性与女性群体中的miR-30c GG基因型，以及男性群体中的miR-223 G基因型，会强化欺凌行为暴露与疼痛之间的关联。

通俗总结：
借助社交应激动物模型，我们鉴定出miR-146a、miR-30c及miR-223为潜在的重要基因调控分子，可能参与应激应答过程。值得注意的是，影响成熟miR-30c与miR-223表达的人类基因型，会对欺凌暴露与疼痛之间的关联产生调控作用。携带miR-30c rs928508 GG基因型的群体，其欺凌行为暴露与疼痛之间的关联显著强于其他群体；与其他男性相比，携带miR-223 rs3848900 G基因型的男性也呈现出相同的现象。借助社交应激动物模型，我们鉴定出miR-146a、miR-30c及miR-223为潜在的重要基因调控分子，可能参与应激应答过程。值得注意的是，影响成熟miR-30c与miR-223表达的人类基因型，会对欺凌暴露与疼痛之间的关联产生调控作用。携带miR-30c rs928508 GG基因型的群体，其欺凌行为暴露与疼痛之间的关联显著强于其他群体；与其他男性相比，携带miR-223 rs3848900 G基因型的男性也呈现出相同的现象。