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Serum microRNA Profiling Yields Mechanistic Insight into a Residential Cohort with Environmental Liver Disease
Citation:
Cave, M., C. Pinkston, S. Rai, G. Carswell, G. Nelson, K. Head, B. Wahlang, Y. Saad, M. Pavuk, AND B. Chorley. Serum microRNA Profiling Yields Mechanistic Insight into a Residential Cohort with Environmental Liver Disease. American Association for the Study of Liver Diseases (AASLD) The Liver Meeting, NA, Virtual, November 13 - 16, 2020. https://doi.org/10.23645/epacomptox.13266578
Impact/Purpose:
Non-invasive biomarkers that are linked to mechanisms of chemical exposure and disease progression can be utilized for biosurveillance scenarios to identify susceptible subpopulations. Here, we explore the use non-coding RNAs in blood, specifically miRNAs, to identify liver disease in a residential cohort of high PCB exposures. This exploratory study will build a foundation of accessible molecular-based biomarkers that may be used to identify fatty liver disease development influenced by environmental pollutant exposure. Long-term, development of these biomarkers will assist risk assessors to determine the impact of pollutantant exposures to human liver health.
Description:
Background: Polychlorinated biphenyls (PCBs) are industrial pollutants previously associated with steatohepatitis. The Anniston Community Health Survey-I (ACHS-1) is a cohort consisting of community participants living near a former PCB production facility in Alabama. In ACHS-I, we previously reported a high prevalence of necrotic liver disease associated with exposures to specific PCB congeners, insulin resistance, and pro-inflammatory cytokines - consistent with PCB-related toxicant-associated steatohepatitis (TASH) (PMID:29684222). MicroRNAs (miRs) are non-coding RNAs that maintain cellular homeostasis. A pilot study demonstrated the potential utility of serum miR profiling in ACHS-I (n=152, DDW 2018, 7110A). Based on those preliminary data, hepatotoxicity miRs were measured in all available ACHS-I participants. Methods: IRB-approval was obtained. A panel of 68 targeted hepatotoxicity miRs (FirePlex, Abcam); the hepatocyte death biomarker, keratin 18 (K18 M30 and M65, ELISA, DiaPharma); and 35 ortho-substituted PCBs (GC/MS) were measured in de-identified, archived serum (n=738). Raw mean fluorescent intensities (MFIs) of 30 highly expressed miRs (>LOD in 90+% of the sample) were quantile-normalized and log10-transformed. Values 300 U/L & M30200 U/L, n=85). For miRs, fold-change was calculated by taking the exponential power of the ratio of the back-transformed MFI values for the two groups with liver disease relative to the no liver disease control group. Associations between miRs and log-transformed values of K18 and summed PCBs were determined using generalized, confounder-adjusted linear models. Data analysis was performed using R (R Core Team), SAS v9.4 (SAS Institute, Cary, NC. USA), and Ingenuity Pathway Analysis (IPA, Qiagen, Hilden, Germany). Statistical significance was set at a p-value ≤0.05 and/or a false discovery rate (FDR) of ≤0.15. Results: Demographic information was previously published (PMID:29684222). Necrotic liver disease was associated with 7 miRs including: miR-122-5p (4.31-fold, FDR<.0001); miR-192-5p (3.32-fold, FDR=0.006); miR-17-5p (0.35-fold, FDR=0.15); miR-221-3p (0.34-fold, FDR=0.15); let-7d-5p (0.34-fold, FDR=0.13); miR-24-3p (0.34-fold, FDR=0.02); and miR-197-3p (0.33-fold, FDR=0.11). Apoptotic liver disease was associated with 6 miRs including: miR-122-5p (18.28-fold, FDR<.0001); miR-192-5p (5.16-fold, FDR=0.001); miR-99a-5p (3.99-fold, FDR=0.008); miR-320a (2.65-fold, FDR=0.15); miR-221-3p (0.30-fold, FDR=0.11); and let-7d-5p (0.29-fold, FDR=0.02). None of these miRs were associated with ΣPCBs. For the necrotic liver disease subgroup, IPA elucidated alterations in pathways associated with gene expression; intermediary metabolism; cell death (necrosis), survival and proliferation; stellate cell activation and hepatic fibrosis; and hepatocellular carcinoma. 20 miRs were associated with continuous k18 values, with four being unique to K18 M65. Discussion: The miR results broadly support the liver disease categorization procedures using K18, which demonstrated an exceptionally high liver disease prevalence in ACHS-1 (60.2%, PMID:29684222), but lacked histologic confirmation. Necrotic and apoptotic liver diseases were associated with slightly different serum miR profiles. The potential impact of environmental PCB exposures on hepatic fibrosis and hepatocellular carcinoma in steatohepatitis warrants further investigation. This does not necessarily reflect the policy of EPA or ATSDR.
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DOI: Serum microRNA Profiling Yields Mechanistic Insight into a Residential Cohort with Environmental Liver Disease
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