Data for 'Transcriptional responses as biomarkers of general toxicity: a systematic review and meta-analysis on metal-exposed bivalves'

Background data and supplementary figures for the paper 'Transcriptional responses as biomarkers of general toxicity: a systematic review and meta-analysis on metal-exposed bivalves'. Published in Environmental Toxicology and Chemistry. DOI: 10.1002/etc.5494 ABSTRACT: Through a systematic review and a series of meta-analyses, we evaluated the general responsiveness of putative transcriptional biomarkers of general toxicity and chemical stress. We targeted metal exposures performed on bivalves under controlled laboratory conditions, and selected six transcripts associated with general toxicity for evaluation: catalase (cat), glutathione-S-transferase (gst), heat shock proteins 70 and 90 (hsp70, hsp90), metallothionein (mt) and superoxide dismutase (sod). Transcriptional responses (n = 396) were extracted from published scientific articles (k = 22) and converted to log response ratios (lnRRs). By estimating toxic units (TUs), we normalized different metal exposures to a common scale, as a proxy of concentration. Using Bayesian hierarchical random effect models, we then tested the effects of metal exposure on lnRR, both for metal exposure in general and in meta-regressions using TU and exposure time as independent variables. Corresponding analyses were also repeated with transcript and tissue as additional moderators. Observed patterns were similar for general as for transcript- and tissue-specific responses. The expected overall response to arbitrary metal exposure was a lnRR of 0.50, corresponding to a 65 % increase relative a non-exposed control. However, when accounting for publication bias, the estimated ‘true’ response showed no such effect. Furthermore, expected response magnitude increased slightly with exposure time, but there was little support for general monotonic concentration-dependence with regards to TU. Altogether, this work reveals potential limitations that need consideration prior to applying the selected transcripts as biomarkers in environmental risk assessment.本数据集为论文《转录反应作为通用毒性生物标志物：金属暴露双壳类动物的系统综述与荟萃分析》的背景数据与补充图表。该论文发表于《Environmental Toxicology and Chemistry》，DOI：10.1002/etc.5494。 摘要：本研究通过系统综述与一系列荟萃分析，评估了通用毒性与化学胁迫相关推定转录生物标志物（transcriptional biomarkers）的整体响应性。研究以受控实验室条件下的双壳类动物（bivalves）金属暴露实验为对象，选取6种与通用毒性相关的转录本进行评估：过氧化氢酶（catalase，CAT）、谷胱甘肽S-转移酶（glutathione-S-transferase，GST）、热休克蛋白70与90（heat shock proteins 70 and 90，HSP70、HSP90）、金属硫蛋白（metallothionein，MT）以及超氧化物歧化酶（superoxide dismutase，SOD）。从已发表的22篇学术文献（k=22）中提取得到396组转录反应数据（n=396），并将其转换为对数反应比（log response ratios，lnRRs）。通过估算毒性单位（toxic units，TUs），将不同金属暴露浓度归一化至统一标尺，以作为暴露浓度的替代指标。随后，采用贝叶斯分层随机效应模型，分别针对整体金属暴露场景，以及以毒性单位和暴露时间为自变量的元回归分析，检验了金属暴露对对数反应比的影响。同时，加入转录本与组织作为额外调节变量，重复上述对应分析。结果显示，整体响应模式与转录本特异性及组织特异性响应模式基本一致。任意金属暴露下的预期整体响应对应的对数反应比为0.50，相较于未暴露对照组，基因表达量提升65%。然而，在纳入发表偏倚校正后，估算得到的‘真实’响应并未呈现此类效应。此外，预期响应强度随暴露时间延长略有上升，但未发现基于毒性单位的显著单调浓度依赖性效应。综上，本研究揭示了在环境风险评估中将所选转录本用作生物标志物前，需考量的潜在局限性。