Literature review of baseline information on non‐coding RNA (ncRNA) to support the risk assessment of ncRNA‐based genetically modified plants for food and feed

Abstract

This report is the outcome of an EFSA procurement (NP/EFSA/GMO/2016/01) reviewing relevant scientific information on ncRNA and on RNA interference (RNAi) that could support the food and feed risk assessment of ncRNA-based genetically modified (GM) plants. Information was retrieved through key words and key questions covering the stability and degradation of ncRNAs after oral ingestion, the passage of ncRNAs from food and feed to human and animal organs and tissues via the gastrointestinal tract and other barriers, as well as the potential effects on the gastrointestinal tract, the immune system or the entire organism. Full description of the strategy used for the literature search and for studies selection is provided and the number of retrieved publications is reported. This report is divided into four parts discussing the kinetics of exogenous ncRNAs in humans and animals, with focus on ingested ncRNAs (Part 1); the possible effects of ncRNAs on the gastrointestinal tract (Part 2), systemically (Part 3) and on the immune system (Part 4). This report suggests that some plant ncRNAs (e.g miRNAs and siRNAs) show higher stability as compared to other ncRNAs due to peculiar chemical characteristics (2'-O-methylation at 3' end). However, ingested or administered ncRNA must overcome many extracellular and cellular barriers to reach the intended target tissue or functional location in sufficient amount to exert any biological effect. Literature data indicate that chemically unmodified and unformulated ncRNAs exhibit very low stability in the gastrointestinal tract and in biological fluids and, in general, do not elicit major biological effects. This report also provides an overview of the RNA content in plant-derived foods and diets and discusses the controversies on the presence of dietary exogenous RNAs in the biological fluids of humans and animals and their effects. Finally, gaps in the scientific literature are highlighted and recommendations provided.

Risk Assessment Considerations for Genetically Modified RNAi Plants: EFSA’s Activities and Perspective

“…The European Food Safety Authority has undertaken several activities on the risk assessment of RNAi-based GMPs to define in which areas existing risk assessment approaches for GMPs are suitable, or require complementary or alternative strategies. These include: (Pačes et al, 2017), while the FF safety report focused on the kinetics and possible effects of non-coding (nc) RNAs, including silencing RNAs, and upon ingestion by humans and animals (Dávalos et al, 2019). The report in support of the environmental risk assessment considered environmental RNAi-related aspects in arthropods, nematodes, and annelids and molluscs (Christiaens et al, 2018).…”

“…As supported by the external scientific report (Dávalos et al, 2019), ncRNAs, including silencing RNAs, are ubiquitous constituents of human and animal diet. Dietary silencing RNAs are known to be rapidly degraded soon after ingestion due to the conditions (e.g., pH) and enzymes present in the gastrointestinal tract lumen, and due to several barriers that exist at cellular (e.g., intestinal mucosa) and intracellular (e.g., lysosomal system) levels, preventing their systemic absorption.…”

“…Therefore, the amount of dietary silencing RNAs absorbed after FF ingestion can be considered negligible in humans and animals (mammals, birds and fish), unless chemical modifications increasing their stability are introduced. The reported widespread presence, yet at low abundance, of exogenous RNAs in human and animal biological fluids, must therefore be viewed critically as it may be due to technical artefacts and contamination (Dávalos et al, 2019). Systemic effects of plant-derived silencing RNAs ingested orally have not been reliably established.…”

RNA‐based biocontrol compounds: current status and perspectives to reach the market

“…FIFRA responded to this document by organizing a meeting the following year that explicitly addressed several concerns pertaining to ecological risk considerations and human health considerations, and provided various recommendations to address uncertainties related to these concerns . A similar exercise was conducted by the European Food Safety Authority (EFSA) which triggered the collection of literature reviews based on scientific information from RNAi studies . These reviews, intended to support the risk assessment of RNAi‐based GM plants, provide a comprehensive overview of RNAi and will also be useful in the development of regulatory guidelines for externally applied RNA‐based biocontrol compounds.…”

“…36 A similar exercise was conducted by the European Food Safety Authority (EFSA) which triggered the collection of literature reviews based on scientific information from RNAi studies. [37][38][39] These reviews, intended to support the risk assessment of RNAi-based GM plants, provide a comprehensive overview of RNAi and will also be useful in the development of regulatory guidelines for externally applied RNA-based biocontrol compounds. With a similar objective, an Organisation for Economic Co-operation and Development (OECD) conference on RNA-based pesticides was recently organized in April 2019 in Paris, with the aim of providing an overview of the current status and future possibilities for the regulation of externally applied dsRNA-based compounds.…”