Targeting cellular senescence alleviates bone marrow aging

Area of Science:

• Hematology
• Gerontology
• Cellular Senescence

Background:

• Aging impairs hematopoietic stem cell (HSC) function, increasing risks of anemia, infections, and hematologic cancers.
• The bone marrow microenvironment (niche) also changes with age, affecting HSC behavior and overall hematopoietic health.

Purpose of the Study:

• To investigate the therapeutic potential of pharmacologic senescent cell clearance in reversing hematopoietic aging.
• To evaluate the efficacy and safety of a novel PROTAC compound (753b) targeting BCL-xL and BCL-2 for rejuvenating the aged hematopoietic system.

Main Methods:

• Utilized a PROTAC compound (753b) to simultaneously target BCL-xL and BCL-2 for senescent cell clearance.
• Employed single-cell RNA sequencing to analyze transcriptional changes in HSCs and niche cells post-treatment.
• Assessed functional outcomes including lineage output, inflammatory markers, and bone marrow secretory ecosystem balance.

Main Results:

• Compound 753b effectively cleared senescent cells with low toxicity, reversing key hallmarks of hematopoietic aging.
• Treatment attenuated aging-associated transcriptional signatures in HSCs and selectively eliminated senescent niche cells.
• 753b suppressed pro-inflammatory cues, rebalanced the bone marrow secretory ecosystem, and restored balanced lineage output.

Conclusions:

• Pharmacologic clearance of senescent cells using 753b is a potent strategy to rejuvenate aged hematopoiesis.
• This approach re-establishes homeostatic communication between HSCs and their microenvironment.
• Senescent cell clearance holds promise for mitigating age-related hematologic dysfunction and improving health in older individuals.