Thank you for covering our paper!

4/5 The Glycobiology Significant Achievement Award:
Dr. Ryan Flynn @raflynn5.bsky.social, Harvard University, 👏👏🥂

Thanks Dr. Doench! Hope you’re doing well!

Big congrats to Vinnie Graziano @vinnieviruses.bsky.social who led the project and huge thanks to our great collaborators: Jennifer Porat, Thomas Carell, Franck Barrat, Beiyan Zhou, Sivapriya Kailasan Vanaja, Michael Wilson, and Penghua Wang!! #innate_immunity #interferon #celldeath

Together, these data reveal one of potentially many answers to the question “why are RNAs glycosylated?” to which we found that it is to prevent autoinduction of RNA-sensing pathways.

Lastly, we found both TLR3 and TLR7 are required for sensing acp3U containing RNAs.

We teamed up with the Carell lab who synthesized an 18-nt long native or acp3U-containing RNA and found acp3U-RNAs were more immunostimulatory than the unmodified RNAs.

To our surprise, cells deficient in acp3U were not able to stimulate macrophages in both our transfection and efferocytosis assays.

Recently, it was found that acp3U (a hypermodified uridine) is an attachment site for N-glycans to RNA. Genetic KOs of the enzyme DTWD2 prevents the synthesis of acp3U resulting in decreased glycoRNA signal.

Injecting WT mice with deglycosylated apoptotic cells was also capable of inducing a localized RNA-driven innate immune response.

We found that treatment of apoptotic cells with PNGase F elicited a potent IFN response when fed to macrophages.

With this in mind, we asked if N-glycans on RNAs promotes the immunologically silent clearance of apoptotic debris through the process of efferocytosis.

Because glycoRNAs are predominantly on the cell surface, we asked how they would behave during apoptosis. For instance, apoptotic cells are cleared constitutively from our system without inducing inflammatory responses through the process of efferocytosis.

Next, we checked to make sure PNGase F was not acting on the cells to induce an IFN response. We treated long RNA fractions (containing no glycoRNAs) with or without PNGase F and observed no production of IFNb, confirming this requires deglycosylation of small RNAs.