How can Death-seq help to improve senolytic therapies?

New research identifies a screening method that helps in the systematic study of cell death and that will enhance the treatment of senescence.

Cellular senescence, marked by prolonged and irreversible cell-cycle arrest, is a key feature of aging, commonly triggered by various stressors like telomere shortening, mitochondrial dysfunction, epigenetic alterations and chromatin instability. Removing senescent cells in mice has been shown to rejuvenate tissue balance during aging and address numerous age-related ailments, with senolytics serving as crucial agents in this cellular elimination process.

Senolytic drugs, including quercetin, navitoclax, fisetin and dasatinib, have been noted to accumulate at sites of chronic disorders and aging, showing effectiveness in treating various serious conditions like cancer, liver damage, cardiovascular disorders, skin conditions, kidney problems, lung disorders, among others.

My take on this: Limited potency and systemic toxicity constrain the local administration and clinical utility of senolytics, prompting exploration of alternative methods such as pooled genetic screens, though recent studies, including an RNAi approach identifying only one target and an Annexin V-based enrichment screen with various limitations, underscore the need for a novel approach.

A recent study published in Cell Metabolism introduces a novel technique dubbed 'Death-seq,' designed to selectively identify cells succumbing to pharmacological or genetic interventions. This method was then integrated with a genome-wide CRISPR screen to pinpoint targets for enhancing senolytic therapy.

Death-seq involves isolating dying cells, enhancing signal amplification and reducing noise, thereby facilitating the screening of live and dying cells in more physiologically relevant models. In this investigation, Death-seq was employed to conduct a genome-wide CRISPR knockout (KO) screen in normal human lung fibroblast cells induced into senescence by doxorubicin (Doxo-SEN). The aim was to determine whether knockout of specific genes would render cells more or less susceptible to senolysis by ABT263, an inhibitor targeting several anti-apoptotic proteins. Subsequently, the distribution of sgRNA in both live and dying cells was analyzed using DNA-seq, followed by evaluation of the impact of each gene knockout.

The study's findings revealed key hits that hindered cell death. Analysis of genetic interaction networks and pathways highlighted enrichment in pathways associated with mTOR signaling, intrinsic apoptosis and SMAC-IAP-caspase interactions. Notably, Death-seq outperformed traditional methods in identifying hits. Alongside ABT-263, multiple parallel screens were devised to identify additional hits that thwarted cell death.

Explore further how into this study and how Death-Seq can contribute to enhancing senolytic therapies right HERE.

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