Form follows function: Nuclear morphology as a quantifiable predictor of cellular senescence

Enlarged or irregularly shaped nuclei are frequently observed in tissue cells undergoing senescence. However, it remained unclear whether this peculiar morphology is a cause or a consequence of senescence and how informative it is in distinguishing between proliferative and senescent cells. Recent research reveals that nuclear morphology can act as a predictive biomarker of senescence, suggesting an active role for the nucleus in driving senescence phenotypes. By employing deep learning algorithms to analyze nuclear morphology, accurate classification of cells as proliferative or senescent is achievable across various cell types and species both in vitro and in vivo. This quantitative imaging-based approach can be employed to establish links between senescence burden and clinical data, aiding in the understanding of age-related diseases, as well as assisting in disease prognosis and treatment response.     

Selection of DNA aptamers specifically interacting with the fibrillar form of the yeast Sup35 protein

Single-stranded DNA aptamers interacting with fibrils of Saccharomyces cerevisiae Sup35p were obtained by the SELEX procedure. The specificity of interactions with Sup35p was investigated for 10 out of 40 selected aptamers. Nine aptamers were found to bind to the fibrillar but not to the monomeric form of Sup35p. The dissociation constant of the aptamer-fibril complex ranged from 0.1 to 1.0 μM for different aptamers. The aptamers can be used to study the prion transformation of Sup35p.     

State of protein B23/nucleophosmin in brain cells

Protein B23/nucleophosmin is a polyfunctional protein existing in cells in numerous structural forms. In this work, for the immunochemical analysis of nucleophosmin we used the antibodies specific to different forms of nucleophosmin, namely, antibodies selectively revealing monomers of all the known forms of this protein and antibodies specific only to isoform B23.1. Homogenates of different rat tissues such as the brain, liver, kidney, lung and heart were used, as well as nuclei from liver and brain cells. For the first time, we show that the structural state of nucleophosmin in brain differs from its state in other tissues, including the liver that is enriched with nucleophosmin. It was revealed that on immunoblots of brain homogenates not only monomeric form of nucleophosmin but also unique SDS-resistant oligomeric forms were detected in the SDS-PAGE. Analysis of nucleophosmin in the cerebellum, cortex, amygdala, brainstem, and hippocampus showed that most enriched with nucleophosmin were hippocampus and cerebellum; on their immunoblots SDS-resistant oligomeric forms of nucleophosmin dominated. Using immunochemical analysis of the protein in primary cultures of cerebellum glial cells and neurons, significant structural differences of nucleophosmin in proliferating glial cells and non-proliferating neurons were revealed for the first time. It was found also that the nucleophosmin content in glial cells is much higher than in neurons and that the main forms of protein B23 in glial cells on immunoblots are the SDS-resistant oligomers, while a monomeric form was present in much smaller quantities. In contrast to glial cells, neurons did not contain such oligomers. In neurons, only trace amounts of a monomeric form of nucleophosmin were found, which were undetectable by the antibodies specific to isoform B23.1.