Colchicine Blocks Tubulin Heterodimer Recycling by Tubulin Cofactors TBCA, TBCB, and TBCE

Abstract

Colchicine has been used to treat gout and, more recently, to effectively prevent autoinflammatory diseases and both primary and recurrent episodes of pericarditis. The anti-inflammatory action of colchicine seems to result from irreversible inhibition of tubulin polymerization and microtubule (MT) assembly by binding to the tubulin heterodimer, avoiding the signal transduction required to the activation of the entire NLRP3 inflammasome. Emerging results show that the MT network is a potential regulator of cardiac mechanics. Here, we investigated how colchicine impacts in tubulin folding cofactors TBCA, TBCB, and TBCE activities. We show that TBCA is abundant in mouse heart insoluble protein extracts. Also, a decrease of the TBCA/β-tubulin complex followed by an increase of free TBCA is observed in human cells treated with colchicine. The presence of free TBCA is not observed in cells treated with other anti-mitotic agents such as nocodazole or cold shock, neither after translation inhibition by cycloheximide. In vitro assays show that colchicine inhibits tubulin heterodimer dissociation by TBCE/TBCB, probably by interfering with interactions of TBCE with tubulin dimers, leading to free TBCA. Manipulation of TBCA levels, either by RNAi or overexpression results in decreased levels of tubulin heterodimers. Together, these data strongly suggest that TBCA is mainly receiving β-tubulin from the dissociation of pre-existing heterodimers instead of newly synthesized tubulins. The TBCE/TBCB+TBCA system is crucial for controlling the critical concentration of free tubulin heterodimers and MT dynamics in the cells by recycling the tubulin heterodimers. It is conceivable that colchicine affects tubulin heterodimer recycling through the TBCE/TBCB+TBCA system producing the known benefits in the treatment of pericardium inflammation.

Cell-Penetrating Dabcyl-Containing Tetraarginines with Backbone Aromatics as Uptake Enhancers

“…The following inhibitors were applied: 5-(N-ethyl-N-isopropyl)amiloride (EIPA) as micropinocytosis inhibitor [ 39 ], chlorpromazine (CPZ) to inhibit clathrin-mediated endocytosis [ 40 ], methyl-beta-cyclodextrin (CyD) to deplete cholesterol from the lipid rafts, and thus to inhibit caveolae-mediated endocytosis [ 41 ]. Finally, colchicine (COL) was used to ascertain if microtubules are involved in the uptake of the peptides [ 42 ] as this agent inhibits microtubule formation [ 43 ].…”

Perinuclear positioning of endosomes can affect PS-ASO activities

“…To further confirm that perinuclear enrichment of PS-ASO containing LEs is due to LE movement along microtubules, HeLa cells expressing GFP-tubulin was incubated with PS-ASOs for 6 h, then treated overnight with or without colchicine, a small molecule that disrupts microtubule network ( 31 ). In control cells, PS-ASOs appeared as some scattered LE foci, but also enriched in the perinuclear area where MTOC is localized (Figure 4A , upper panel).…”

Colchicine for prevention of post-operative atrial fibrillation: Meta-analysis of randomized controlled trials

“…Microtubules play a key role in cellular cytoskeletal and intracellular transport activities. Colchicine can disrupt microtubule assembly in cells ( 41 , 42 ). Moreover, colchicine inhibits the assembly of the NLRP3 inflammasome, prevents the activation of caspase-1, and reduces the release of IL-1β, IL-6 and superoxide ( 43 – 45 ).…”