RESUMO
During animal cell division, the central spindle, an anti-parallel microtubule bundle structure formed between segregating chromosomes during anaphase, cooperates with astral microtubules to position the cleavage furrow. Because the central spindle is the only structure linking the two halves of the mitotic spindle, it is under mechanical tension from dynein-generated cortical pulling forces, which determine spindle positioning and drive chromosome segregation through spindle elongation. The central spindle should be flexible enough for efficient chromosome segregation while maintaining its structural integrity for reliable cytokinesis. How the cell balances these potentially conflicting requirements is poorly understood. Here, we demonstrate that the central spindle in C. elegans embryos has a resilient mechanism for recovery from perturbations by excess tension derived from cortical pulling forces. This mechanism involves the direct interaction of two different types of conserved microtubule bundlers that are crucial for central spindle formation, PRC1 and centralspindlin.
Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Cinesinas/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Fuso Acromático/fisiologia , Sequência de Aminoácidos , Animais , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/genética , Citocinese , Dados de Sequência Molecular , Estresse MecânicoRESUMO
In this viewpoint, we describe the strategies for engineered negligible senescence (SENS) concept--a simple and appealing model for the design of therapeutic interventions able to meaningfully and persistently reverse the deleterious effects of aging. We go on to outline how current or foreseeable biotechnologies could feasibly be employed to repair every currently identified category of pathogenic damage that accumulates over a human lifespan. Then, briefly, we explain why this goal is not only ethically sound, but can in fact be considered to verge on an ethical obligation. Finally, we review recent progress in some key areas of the SENS platform, including proof-of-concept research sponsored by the SENS Foundation, a charity based in California.
Assuntos
Envelhecimento , Geriatria/métodos , Medicina Regenerativa/métodos , Morte Celular , Proliferação de Células , Senescência Celular , Humanos , Modelos BiológicosRESUMO
A major type of unwanted cells that accumulate in aging are anergic cytotoxic T cells. These cells often have virus-specific T cell receptors, as well as other surface markers that distinguish them from their youthful counterparts, and they are thought to play a major role in the decline of the immune system with age. Here we consider two surface markers thought to define these cells in mice, CD8 and Killer cell lectin-like receptor G1 (KLRG1), and a means we developed to remove these cells from the blood of aged C57BL/6 mice. Using antibodies with magnetic nanoparticles linked to their Fc domains, we first developed a method to use magnets to filter out the unwanted cells from the blood and later constructed a device that does this automatically. We demonstrated that this device could reduce the KLRG1-positive CD8 cell count in aged mouse blood by a factor of 7.3 relative to the total CD8 cell compartment, reaching a level typically seen only in very young animals.
