TENT5 cytoplasmic noncanonical poly(A) polymerases regulate the innate immune response in animals

Abstract

Innate immunity is the first line of host defense against pathogens. Here, through global transcriptome and proteome analyses, we uncover that newly described cytoplasmic poly(A) polymerase TENT-5 (terminal nucleotidyltransferase 5) enhances the expression of secreted innate immunity effector proteins in Caenorhabditis elegans . Direct RNA sequencing revealed that multiple mRNAs with signal peptide–encoding sequences have shorter poly(A) tails in tent-5 –deficient worms. Those mRNAs are translated at the endoplasmic reticulum where a fraction of TENT-5 is present, implying that they represent its direct substrates. Loss of tent-5 makes worms more susceptible to bacterial infection. Notably, the role of TENT-5 in innate immunity is evolutionarily conserved. Its orthologs, TENT5A and TENT5C, are expressed in macrophages and induced during their activation. Analysis of macrophages devoid of TENT5A/C revealed their role in the regulation of secreted proteins involved in defense response. In summary, our study reveals cytoplasmic polyadenylation to be a previously unknown component of the posttranscriptional regulation of innate immunity in animals.

SARS-CoV-2 mRNA vaccine is re-adenylatedin vivo, enhancing antigen production and immune response

“…Most mRNAs with poly(A) tails elongated after vaccination in WT BMDMs, but not Tent5a Flox/Flox / Tent5c -/- BMDMs, (ED Fig. 5b) encode extracellular proteins translated at the endoplasmic reticulum (ER), in line with previous findings regarding TENT5A/C substrates 26,27 . Notably, mRNA-1273 also encodes an ER-targeted protein, which, as we show, hijacks TENT5s to extend its poly(A) tail.…”

“…They included MHC components ( H2-K1, H2-D1, H2-T23, B2m ), serum complement components ( C1qb, C1qc ), lysosomal proteins ( Lamp1, Laptm5 ), and innate immune response genes ( Ctsb, Ctsd, ApoE, Lyz2, Cst3, Ctss ). Remarkably, in our previous study on BMDMs activated with LPS 26 , a similar set of transcripts was revealed to be substrates of TENT5A/TENT5C non-canonical poly(A) polymerases. Therefore, we examined gene expression changes of all known non-canonical poly(A)/poly(U) polymerases and found that Tent5a is the only polymerase that is significantly induced at vaccine injection sites and after vaccine treatment in BMDMs ( Fig.…”

“…TENT5A/C also affected endogenous transcripts as no extension of poly(A) tails following vaccination was observed for mRNAs noticed in WT (ED Fig. 5b, Supplementary Table 6), including innate immunity effector transcripts (clusters 1,2), previously observed in LPS-activated macrophages 26 . Importantly, dysfunction of TENT5-mediated cytoplasmic polyadenylation did not affect the transcriptional response, which was similar for both WT and Tent5a Flox/Flox / Tent5c BMDMs (ED Fig.…”

“…However, DCs express low levels of TENT5, raising the question of whether TENT5-mediated stabilization of vaccine mRNA in macrophages affects immune response. TENT5C is expressed in B cells, and was shown to regulate the humoral response by polyadenylation of immunoglobulin transcripts 28 , whereas TENT5A was described only in the context of innate immunity 26 . Thus, we immunized WT and Tent5a -/- mice with mRNA-1273, and measured antigen and antibody production ( Fig.…”

“…To evaluate the role of TENT5 proteins in vaccine mRNA re-adenylation, we studied mRNA-1273 metabolism in BMDMs devoid of TENT5A and TENT5C (double-knockout Tent5a Flox/Flox /Tent5c -/- ) 26 . Double-knockout BMDM cells were treated with mRNA-1273 for up to 72 h, RNA was isolated and subjected to eDRS.…”