Paternal methotrexate exposure affects sperm small RNA content and causes craniofacial defects in the offspring

ALATA JIMENEZ, NAGIF; CASTELLANO, M.; SANTILLAN, E.; BOULIAS, KONSTANTINOS; BOAN, AGUSTÍN; ARIAS PADILLA, L.F.; FERNANDINO, JUAN I.; GREER, ERIC LIEBERMAN; TOSAR, JUAN PABLO; COCHELLA, LUISA; STROBL-MAZZULLA, PABLO H.

NATURE COMMUNICATIONS

Nature Publishing Group

Año: 2023

2041-1723

Folate is an essential vitamin for vertebrate embryodevelopment. Methotrexate (MTX) is a folate antagonist that is widely prescribedfor autoimmune diseases, blood and solid organ malignancies, and dermatologicdiseases. Although it is highly contraindicated for pregnant women, because itis associated with an increased risk of multiple birth defects, the effect ofpaternal MTX exposure on their offspring has been largelyunexplored. Here, we found MTX treatment of adult medaka male fish (Oryzias latipes) causes cranialcartilage defects in their offspring. Small non-coding RNA (sncRNAs) sequencingin the sperm of MTX treated males identify differential expression of a subsetof tRNAs, with higher abundance for specific 5’ tRNA halves. Sperm RNAmethylation analysis on MTX treated males shows that m5C is the most abundantand differential modification found in RNAs ranging in size from 50 to 90nucleotides, predominantly tRNAs, and that it correlates with greatertesticular Dnmt2 methyltransferaseexpression. Injection of sperm small RNA fractions from MTX-treated males intonormal fertilized eggs generated cranial cartilage defects in the offspring. Overall,our data suggest that paternal MTX exposure alters sperm sncRNAs expression andmodifications that may contribute to developmental defects in their offspring.