Rogowski, K. | Search bioRxiv

bioRxiv2025

Pyruvate promotes ciliogenesis bypassing IFT88 dependency and attenuates DSS-induced colitis

Primary cilia (PC) are important signaling rheostats, yet their biology in colon remains understudied. We previously reported that the presence of PC on colonic fibroblasts in mice (CF) modulates their susceptibility to colitis. Here, we demonstrate that extracellular pyruvate levels influence both ciliary length and ciliogenesis in CF. Pyruvate supplementation to CF enhanced tubulin and histone acetylation, with the latter promoting MAPK signaling and tubulin detyrosination within PC. MAPK-inhibition reduced tubulin detyrosination and shortened ciliary length, while inhibition of -tubulin acetylation specifically affected ciliogenesis. Col6a1cre-Ift88flx/flx mice, lacking ciliary Ift88 gene in Col6a1-expressing CF, displayed reduced ciliogenesis and increased susceptibility to DSS-induced colitis. Surprisingly, in primary CF cultures from these mice, pyruvate supplementation restored PC formation. Moreover, pyruvate administration via drinking water rescued PC formation in Col6a1cre-Ift88flx/flx mice and attenuated DSS-induced colitis. These findings identify pyruvate as a regulator of PC biology in CF and as a therapeutically relevant factor in colitis. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=172 HEIGHT=200 SRC="FIGDIR/small/694572v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@170091dorg.highwire.dtl.DTLVardef@66870corg.highwire.dtl.DTLVardef@12c5124org.highwire.dtl.DTLVardef@834660_HPS_FORMAT_FIGEXP M_FIG Pyruvate promotes ciliogenesis bypassing IFT88 dependency and attenuates DSS-induced colitis C_FIG

pathology↗

bioRxiv2025

TTLL6-mediated Polyglutamylation of PurA Maintains Colonic Crypt Integrity

The tubulin tyrosine ligase-like (TTLL) family comprises enzymes catalyzing posttranslational modifications of tubulin, including glutamylation and glycylation. We previously described a critical role for the monoglycylase TTLL3 in colon. Here, we identified TTLL6 as the predominant polyglutamylase in the colon, specifically expressed in epithelial cells of distal and transverse segments. TTLL6 expression decreases during CRC progression, correlating with poor patient prognosis. Deletion of Ttll6 in mice resulted in elongated colonic crypts, expansion of stem and transit-amplifying compartments, and increased numbers of differentiated epithelial cells. Moreover, Ttll6-deficient mice showed an elevated susceptibility to chemically induced colon carcinogenesis. Notably, we identified the nucleic acid-binding protein PurA as a novel TTLL6 substrate with both proteins mutually required for nuclear localization. Consistently, both nuclear polyglutamylation and PurA were present in the bottom compartment of control colons, but reduced in Ttll6-deficient colons. These findings reveal a TTLL6-PurA axis being critical in maintaining colonic homeostasis.

cell biology↗