Microbiota-independent antiviral protection conferred by aminoglycoside antibiotics

Smita Gopinath; Myoungjoo V. Kim; Tasfia Rakib; Patrick W. Wong; Michael van Zandt; Natasha A. Barry; Tsuneyasu Kaisho; Andrew L. Goodman; Akiko Iwasaki

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/248617 doi: bioRxiv preprint DCs (cDC1) from the thymus and spleen ( Supplementary Fig. 10 ). In non-lymphoid tissue, 299 these cells are characterized as CD103+ DCs and both subsets express high levels of 300 TLR3 (Ref. 29 ). Recent studies have identified XCR1 as a defining cell surface marker for 301 cDC1 subset 30 . Thus, we measured the recruitment of XCR+CD103+ DCs in the vaginal 302 mucosa. Neomycin treatment resulted in significant recruitment of CD103+ XCR1+DCs 303 that were ablated upon treatment with pertussis toxin (Fig. 6a,b) . To determine if this was 304 the DC subtype responsible for ISG induction by aminoglycosides, we depleted mice of 305 The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/248617 doi: bioRxiv preprint Aminoglycosides acts by binding bacterial ribosomal RNA, but it also binds mitochondrial 324 and mammalian ribosomal RNA 38-40 . Our data show that aminoglycoside induction of ISG 325 requires TLR3, which is a sensor of dsRNA. Thus, we tested if aminoglycosides induce 326 ISG expression by rendering host RNA more 'visible' to TLR3 in neighboring DCs. To test 327 this, we first treated splenocytes with kasugamycin and washed the cells multiple times to 328 remove extracellular aminoglycosides. Next, we incubated these kasugamycin-treated 329 cells with splenic DCs that include XCR1+ DCs from WT and TLR3 knockout mice and 330 measured DC-specific ISG expression. Incubation with kasugamycin-treated splenocytes 331 was sufficient to increase ISG expression in WT but not TLR3 -/-DCs (Supplementary Fig. 332 12). 333