**Characterization of MicroRNA and Gene Expression Profiles Following Ricin Intoxication**

#### **Nir Pillar, Danielle Haguel, Meitar Grad, Guy Shapira, Liron Yo**ff**e and Noam Shomron \***

Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; nirpillar@gmail.com (N.P.); Haguel@mail.tau.ac.il (D.H.); meitargrad@gmail.com (M.G.); guyspersonal@gmail.com (G.S.); lironyoffe@gmail.com (L.Y.)

**\*** Correspondence: nshomron@post.tau.ac.il; Tel.: +972-3-640-6594

Received: 25 March 2019; Accepted: 30 April 2019; Published: 2 May 2019

**Abstract:** Ricin, derived from the castor bean plant, is a highly potent toxin, classified as a potential bioterror agent. Current methods for early detection of ricin poisoning are limited in selectivity. MicroRNAs (miRNAs), which are naturally occurring, negative gene expression regulators, are known for their tissue specific pattern of expression and their stability in tissues and blood. While various approaches for ricin detection have been investigated, miRNAs remain underexplored. We evaluated the effect of pulmonary exposure to ricin on miRNA expression profiles in mouse lungs and peripheral blood mononuclear cells (PBMCs). Significant changes in lung tissue miRNA expression levels were detected following ricin intoxication, specifically regarding miRNAs known to be involved in innate immunity pathways. Transcriptome analysis of the same lung tissues revealed activation of several immune regulation pathways and immune cell recruitment. Our work contributes to the understanding of the role of miRNAs and gene expression in ricin intoxication.

**Keywords:** ricin; microRNA; lung intoxication

**Key Contribution:** We describe a miRNA and gene expression profile of pulmonary ricin intoxication leading to an enrichment of innate immune response pathways.
