Biology subjects

Bufe, A.

Publications and source records attributed to Bufe, A..

3 recordsLinked to original sources

bioRxiv2025

Long-term daily light exposure boosts photoreceptor maturation in retinal organoids

Induced pluripotent stem cell-derived retinal organoids (ROs) have become promising personalized models to study inherited retinal diseases (IRDs) and develop new innovative therapies. Although ROs mimic key retinal features and show some light responsiveness, their differentiation and maturation remain limited and lengthy. We hypothesize that standard dark culture conditions limit the expression of genes and proteins related to retinal function, delaying differentiation and complicating disease modeling. Therefore, we investigated whether daily light exposure could promote photoreceptor maturation. ROs were exposed to six hours of daily light starting from day 70 in vitro. Light conditioning led to enhanced photoreceptor maturation, specifically an increase in rod photoreceptors, a late-born cell type, without signs of increased stress or cell death. Our findings suggest that daily light exposure enhances RO differentiation, opening new avenues to investigate molecular and cellular phenotypes in IRDs and accelerate therapy development in more relevant functional models.

cell biology↗

bioRxiv2023

A signalling rheostat controls chromosome segregation fidelity during early lineage specification and neurogenesis by modulating DNA replication stress

The development and homeostasis of organisms rely on the correct replication, maintenance and segregation of their genetic blueprints. How these intracellular processes are monitored across generations of different human cellular lineages, and why the spatio-temporal distribution of mosaicism varies during development remain unknown. Here, we identify several lineage specification signals that regulate chromosome segregation fidelity in both human and mouse pluripotent stem cells. Through epistatic analyses, we find that that WNT, BMP and FGF form a signalling "rheostat" upstream of ATM that monitors replication fork velocity, origin firing and DNA damage during S-phase in pluripotency, which in turn controls spindle polymerisation dynamics and faithful chromosome segregation in the following mitosis. Cell signalling control of chromosome segregation fidelity declines together with ATM activity after pluripotency exit and specification into the three human germ layers, or further differentiation into meso- and endoderm lineages, but re-emerges during neuronal lineage specification. In particular, we reveal that a tug-of-war between FGF and WNT signalling in neural progenitor cells results in DNA damage and chromosome missegregation during cortical neurogenesis, which could provide a rationale for the high levels of mosaicism in the human brain. Our results highlight a moonlighting role of morphogens, patterning signals and growth factors in genome maintenance during pluripotency and lineage specification, which could have important implications for our understanding on how mutations and aneuploidy arise during human development and disease. One sentence summaryDevelopmental signals link genome maintenance to cell fate

cell biology↗

bioRxiv2020

Wnt signaling recruits KIF2A to the spindle to ensure chromosome congression and alignment during mitosis

Canonical Wnt signaling plays critical roles in development and tissue renewal by regulating {beta}-catenin target genes. Recent evidence showed that {beta}-catenin-independent Wnt signaling is also required for faithful execution of mitosis. This mitotic Wnt signaling functions through Wnt-dependent stabilization of proteins (Wnt/STOP), as well as through components of the LRP6 signalosome. However, the targets and specific functions of mitotic Wnt signaling still remain uncharacterized. Using phosphoproteomics, we identified that Wnt signaling regulates the microtubule depolymerase KIF2A during mitosis. We found that Dishevelled recruits KIF2A via its N-terminal and motor domains, which is further promoted upon LRP6 signalosome formation during mitosis. We show that Wnt signaling modulates KIF2A interaction with PLK1, which is critical for KIF2A localization at the spindle. Accordingly, Wnt signaling promotes chromosome congression and alignment by monitoring KIF2A protein levels at the spindle poles both in somatic cells and in pluripotent stem cells. Our findings highlight a novel function of Wnt signaling during cell division, which could have important implications for genome maintenance, notably in stem cells. SIGNIFICANCEWnt signaling plays essential roles in embryonic patterning, stem cell renewal, and cell cycle progression from G1 to S phase via the regulation of {beta}-catenin target genes. Here, we show that Wnt signaling also promotes faithful execution of mitosis by ensuring chromosome congression and alignment before cell division, including in pluripotent stem cells. We demonstrate that the Wnt signaling transducer Dishevelled recruits the mitotic kinesin KIF2A, and mediates its binding to the spindle. KIF2A is a microtubule depolymerase that controls chromosome alignment and congression during mitosis. Consequently, we found that inhibition of Wnt signaling leads to KIF2A-dependent chromosome congression and alignment defects.

cell biology↗