微小核醣核酸表現量和首發精神病患治療六個月後症狀改善之關聯

Abstract

背景與目的 周邊血液中表現異常的微小核醣核酸 (microRNA, miRNA) 和思覺失調症有關。然而， miRNA 表現量在不同時間長度的長期追蹤的研究當中結果並不一致，每篇研究探討的 miRNA 數量亦有不同。對於臨床效益重要的是基線 miRNA 表現異常能否預測數月後的臨床結果。目前為止只有一篇研究檢驗單一miRNA (miR-195)，並發現其基線表現量與兩個月後症狀改善之間有關，然而在全基因體中是否能發現更多表現異常且和症狀改善之間有關的miRNA目前並不清楚。因此，本研究的目的是利用微陣列 (microarray) 實驗找出能預測病人治療六個月症狀改善的miRNA，以及探索其潛在的生物功能。 方法 本研究於臺灣北部 3 間醫院及 2 間診所招募而來並且在 6 個月後仍可以追蹤到的 41 位首次發作精神病病人。治療 6 個月後活性與負性症狀量表 (Positive and Negative Syndrome Scale, PANSS) 得分下降 20% 以上定義為治療反應良好者 (n=17)，其餘病人為反應不佳者 (n=24)。使用 GeneChip miRNA 4.0 Array 掃描病人基線的周邊血液單核細胞中 miRNA 表現量，統計方面使用多變量羅吉斯迴歸分析校正病人年齡及來源（住院/門診病人）後找出潛在和臨床症狀改善有關的 miRNA，微陣列分析中差異倍數 (fold change) 最高的前 15 個且顯著的 miRNA 使用定量即時逆轉錄聚合?連鎖反應分析 (Quantitative reverse transcriptase polymerase chain reaction, qRT-PCR) 做再次的驗證。並利用Ingenuity Pathway Analysis (IPA) 預測被驗證的 miRNA 所調控的基因及了解潛在的生物功能。 結果 在 15 個再次驗證的miRNA中，僅有 2 個 miRNA（hsa-miR-34a-5p和hsa-miR-299-5p）在校正病人來源（住院/門診病人）和年齡後仍然和病人治療六個月後症狀改善之間有關。合併hsa-miR-34a-5p和hsa-miR-299-5p的曲線下面積 (Area Under the Curve, AUC) 達85.8% （95%信賴區間：74.7-96.8%）。使用IPA分析顯示hsa-miR-34a-5p調控的基因參與神經傳遞有關的路徑，而hsa-miR-299-5p調控的基因參與在和發炎反應有關的路徑。 結論 基線周邊血液中表現較高的 hsa-miR-34a-5p 和 hsa-miR-299-5p 與治療六個月後較高的機率成為治療反應良好者有關，這兩個 miRNA調控的基因可能有助於闡釋並支持思覺失調症患者治療反應異質性之因素。

Background Aberrant expressions of microRNAs (miRNAs) in peripheral blood have been associated with the diagnosis of schizophrenia. However, the results of longitudinal follow-up of miRNA expression levels have been conflicting in previous studies, with differences in the length of follow-up and the number of miRNAs examined. From a view point of clinical utility, it is of importance to ask whether the aberrant expressions of miRNAs at baseline could predict the clinical outcome several months later. To date, only a study examining a single miRNA (miR-195) in schizophrenia patients found an association between its expression levels and psychotic symptom improvement 2 months later. Whether the expression aberrations in genome-wide miRNAs can detect more miRNAs with expression levels that were associated with improvement in psychotic symptoms in a time period longer than 2 month remains unknown. This study aimed to identify potential miRNAs as biological predictors of symptom improvement after 6-month of treatment and explore the potential biological functions of target genes using microarray analysis in the first-episode psychotic patients. Methods Participants of this study were 41 patients with first episode psychosis recruited from three hospitals and two private clinics in northern Taiwan and having data at 6-month follow-up. Patients with more than 20% reduction in Positive and Negative Syndrome Scale (PANSS) after six months of treatment were classified as good responders (n = 17) and the remaining patients as poor responders (n = 24). The genome-wide miRNA expressions were measured using a GeneChip miRNA 4.0 Array in the peripheral blood mononuclear cells of the psychotic patients at baseline. Multivariable logistic regression analysis of 6-month treatment response on individual miRNA’s expression level with adjustment for patients’ age and type of patient source (inpatient vs. outpatient) was used to identify potential miRNAs associated with clinical outcome. The top 15 miRNAs in fold-change with significant change in the microarray analysis were selected for validation by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). For those validated miRNAs, Ingenuity Pathway Analysis (IPA) was utilized to explore genes targeted by the miRNAs and their potential functions. Results Out of 15 miRNAs selected for qRT-PCR validation, two miRNAs, hsa-miR-34a-5p and hsa-miR-299-5p, remained significantly associated with 6-month clinical outcome with adjustment for patient source (inpatient/ outpatient) and age. The combination of the two differentially expressed miRNAs led to the highest area under the curve (AUC) of receiver operating characteristics of 85.8% (95% CI: 74.7-96.8%). Analysis using IPA revealed that the targeted genes of hsa-miR-34a-5p were engaged in the pathways related to neurotransmission, and those of hsa-miR-299-5p were involved in the pathways associated with inflammation. Conclusions Higher expression levels of hsa-miR-34a-5p and hsa-miR-299-5p in peripheral blood at baseline were associated with higher likelihood to be good responders after 6 months of treatment. The pathway genes regulated by these two miRNAs may help elucidate the nature underpinning the heterogeneous treatment responses in patients with schizophrenia.