Biology subjects

Coene, J.

Publications and source records attributed to Coene, J..

3 recordsLinked to original sources

bioRxiv2024

Polyamines regulate cell fate by altering the activity of histone-modifying enzymes

Polyamines are polycationic alkyl-amines abundant in proliferating stem and cancer cells. How these metabolites influence numerous cellular processes remains unclear. Here we show that polyamine levels decrease during differentiation and that inhibiting polyamine synthesis leads to a differentiated-like cell state. Polyamines are enriched in the nucleus, where their loss drives changes in chromatin accessibility and histone post-translational modifications. Polyamines interact electrostatically with DNA on the nucleosome core, freeing histone tails to conformations accessible to chromatin-modifying enzymes. Consistent with their role in increasing histone-tail accessibility, polyamines are able to replace MYCs role in reprogramming to pluripotency. These data reveal a mechanism by which an abundant metabolite influences chromatin structure and function in a direct but sequence independent manner, facilitating chromatin remodeling during reprogramming and limiting it during fate commitment.

cell biology↗

bioRxiv2022

Novel green fluorescent polyamines to analyze ATP13A2 and ATP13A3 activity in the mammalian polyamine transport system

Cells acquire the polyamines putrescine (PUT), spermidine (SPD) and spermine (SPM) via the complementary action of polyamine uptake and synthesis pathways. The endosomal P5B-type ATPases ATP13A2 and ATP13A3 emerge as major determinants of mammalian polyamine uptake. Our biochemical evidence shows that fluorescently labeled polyamines are genuine substrates of ATP13A2. They can be used to measure polyamine uptake in ATP13A2 and ATP13A3-dependent cell models resembling radiolabeled polyamine uptake. We further report that ATP13A3 enables faster and stronger cellular polyamine uptake than ATP13A2. We also compared the uptake of new green-fluorescent PUT, SPD and SPM analogs using different coupling strategies (amide, triazole or isothiocyanate) and fluorophores (symmetrical BODIPY, BODIPY-FL and FITC). ATP13A2 promotes the uptake of various SPD and SPM analogs, whereas ATP13A3 mainly stimulates the uptake of PUT and SPD conjugates. However, the polyamine linker and coupling position on the fluorophore impacts the transport capacity, whereas replacing the fluorophore affects polyamine selectivity. The highest uptake in ATP13A2 or ATP13A3 cells is observed with BODIPY-FL-amide conjugated to SPD, whereas BODIPY-PUT analogs are specifically taken up via ATP13A3. We found that P5B-type ATPase isoforms transport fluorescently labeled polyamine analogs with a distinct structure-activity relationship (SAR) suggesting that isoform-specific polyamine probes can be designed.

biochemistry↗

bioRxiv2017

Cognitive deficits and increases in creatine precursors in a brain-specific knockout of the creatine transporter gene Slc6a8

Creatine transporter (CrT; SLC6A8) deficiency (CTD) is an X-linked disorder characterized by severe cognitive deficits, impairments in language, and an absence of brain creatine (Cr). In a previous study, we generated floxed Slc6a8 (Slc6a8flox) mice to create ubiquitous Slc6a8 knockout (Slc6a8-/y) mice. Slc6a8-/y mice lacked whole body Cr and exhibited cognitive deficits. While Slc6a8-/y mice have a similar biochemical phenotype to CTD patients, they also showed a reduction in size and reductions in swim speed that may have contributed to the observed deficits. To address this, we created brain-specific Slc6a8 knockout (bKO) mice by crossing Slc6a8Flox mice with Nestin-cre mice. bKO mice had reduced cerebral Cr levels while maintaining normal Cr levels in peripheral tissue. Interestingly, brain concentrations of the Cr synthesis precursor guanidinoacetic acid were increased in bKO mice. bKO mice had longer latencies and path lengths in the Morris water maze, without reductions in swim speed. In accordance with data from Slc6a8-/y mice, bKO mice showed deficits in novel object recognition as well as contextual and cued fear conditioning. bKO mice were also hyperactive, in contrast with data from the Slc6a8-/y mice. The results demonstrate that the loss of cerebral Cr is responsible for the learning and memory deficits seen in ubiquitous Slc6a8-/y mice.

neuroscience↗