Engineered Exosomes Deliver Active Telomerase to Reverse Aging in Mice
Scientists packaged the full telomerase enzyme into extracellular vesicles and reversed multiple hallmarks of aging in aged mice.
Résumé
Researchers at the Beijing Institute of Biotechnology demonstrated that extracellular vesicles (EVs) can encapsulate and deliver functionally active telomerase—including both the TERT protein and TERC RNA—to recipient cells. Using engineered HeLa and 293FT cell lines with overexpressed, knocked-down, or knocked-out telomerase components, they confirmed that EV telomerase activity scales with donor cell TERT expression. When these telomerase-loaded EVs were administered to aged C57BL/6 mice, they restored endogenous telomerase activity, preserved telomere length, reduced reactive oxygen species, lowered senescence markers, and promoted cell proliferation across multiple tissues. The findings position EVs as a promising, biocompatible delivery platform for multi-component enzyme complexes in age-related and telomerase-deficiency diseases.
Résumé détaillé
Telomere shortening is a central driver of cellular senescence and aging-associated disease. Telomerase—the ribonucleoprotein complex comprising the reverse transcriptase TERT and the RNA template TERC—counteracts this shortening, but its activity is suppressed in most adult somatic cells. Mutations or deficiencies in telomerase components underlie serious conditions including dyskeratosis congenita, aplastic anemia, and idiopathic pulmonary fibrosis. Existing therapeutic strategies such as gene therapy and small-molecule activators carry risks of off-target effects, immunogenicity, and tumorigenicity, motivating the search for safer, more targeted delivery systems.
This study investigated whether extracellular vesicles (EVs)—nanoscale lipid bilayer particles naturally secreted by cells—could serve as vehicles for delivering the complete, functional telomerase holoenzyme. The research team generated stable HeLa cell lines with TERT and/or TERC overexpression, lentiviral shRNA knockdown, or CRISPR/Cas9 knockout. EVs were isolated from conditioned media using the EXODUS H-600 system and from mouse serum by sequential ultracentrifugation, then characterized by nanoparticle tracking analysis (NTA), transmission electron microscopy, Western blot for canonical markers (CD9, Alix, TSG101, absence of calnexin), SP-IRIS, and dynamic light scattering for zeta potential and PDI.
A key finding was that telomerase activity within EVs, measured by the Telomeric Repeat Amplification Protocol (TRAP) assay, directly correlated with donor cell TERT expression levels. EVs from TERT-overexpressing cells contained substantially higher telomerase activity, while EVs from knockdown or knockout lines showed reduced or absent activity. Both TERT protein and TERC RNA were confirmed present inside the vesicles, indicating packaging of the multi-component holoenzyme rather than isolated subunits.
In functional delivery experiments, PKH67-labeled EVs were efficiently taken up by human umbilical vein endothelial cells (HUVECs) and mouse embryonic fibroblasts (MEFs). EV-treated cells showed restored intracellular telomerase activity, reduced reactive oxygen species (ROS), decreased apoptosis under H₂O₂-induced oxidative stress, lower expression of senescence-associated markers (p21, p16, β-galactosidase activity), and enhanced proliferative capacity. In aged C57BL/6 mice, systemic EV administration preserved telomere integrity and attenuated senescence phenotypes across multiple tissues, demonstrating in vivo efficacy beyond cell culture models.
These results establish proof-of-concept for EV-mediated intercellular transfer of a functionally active, multi-subunit enzyme complex—a significant advance over prior EV delivery studies that focused on single nucleic acid or protein cargoes. The authors propose this platform as a foundation for therapeutic development targeting telomerase-deficiency diseases and broad aging pathology, though substantial translational work remains before clinical application.
Principales conclusions
- EVs encapsulate both TERT protein and TERC RNA, packaging the complete functional telomerase holoenzyme.
- Telomerase activity inside EVs scales directly with donor cell TERT expression levels, confirmed by TRAP assay.
- Telomerase-loaded EVs restored endogenous telomerase activity and reduced senescence markers in recipient HUVECs and MEFs.
- Aged mice receiving telomerase-loaded EVs showed preserved telomere integrity and attenuated multi-tissue senescence.
- EV-treated cells exhibited reduced ROS, lower apoptosis, and improved proliferation under oxidative stress conditions.
Méthodologie
The study used engineered HeLa cell lines (TERT/TERC overexpression, shRNA knockdown, CRISPR/Cas9 knockout) as EV donor cells; EVs were isolated by size-exclusion chip or ultracentrifugation and characterized by NTA, TEM, Western blot, SP-IRIS, and DLS. Functional delivery was assessed in HUVECs, MEFs, and aged C57BL/6 mice using TRAP assay, ROS quantification, flow cytometric apoptosis, β-galactosidase staining, and senescence marker expression.
Limites de l'étude
The in vivo experiments used aged mice and lacked long-term safety data, including oncogenicity surveillance, which is critical given telomerase's role in cancer. The study does not address EV biodistribution, tissue-specific targeting, or dose optimization needed for clinical translation. Inconsistencies in the telomerase transfer literature cited by the authors suggest the magnitude of functional benefit may be context- and cell-type-dependent.
Ce résumé vous a plu ?
Recevez les dernières recherches sur la longévité dans votre boîte de réception chaque semaine.
Saisissez votre e-mail pour vous abonner :