Circular RNA reprogramming rejuvenates cultured mesenchymal stem cells
Lipid nanoparticle-delivered circular RNA encoding OCT4, SOX2 and KLF4 rejuvenated senescent stem cells in vitro without triggering pluripotency.
Summary
Mesenchymal stem cells can become senescent during laboratory expansion, reducing their usefulness for cell therapies. Researchers developed a lipid nanoparticle-delivered circular RNA that transiently co-expresses OCT4, SOX2 and KLF4 without genomic modification. The abstract reports reduced senescence markers, DNA damage markers and inflammatory cytokine secretion in late-passage cells, alongside recovery of proliferation, migration and tri-lineage differentiation to levels comparable to early-passage cells. An ESRG-targeting digital PCR assay supported the authors' conclusion that circ-OSK alone did not induce pluripotent conversion under the tested conditions. Cell identity and genome integrity were also reported to be preserved. These laboratory findings suggest a potential way to improve MSC products, but the supplied excerpt does not provide detailed protocols, effect sizes or clinical evidence.
Detailed Summary
Mesenchymal stem cells (MSCs) can develop replicative senescence during expansion in culture, reducing their proliferative capacity and therapeutic potential. Partial reprogramming aims to reverse age-associated cellular features without erasing cell identity, but unintended conversion to pluripotency remains a safety concern.
The researchers developed circ-OSK, a circular RNA co-expressing OCT4, SOX2 and KLF4, delivered through lipid nanoparticles. According to the abstract, this platform provides transient, coordinated expression without genomic modification. The researchers also used a validated droplet digital PCR assay targeting the pluripotency marker ESRG. They report that circ-OSK alone was insufficient to convert MSCs into induced pluripotent stem cells under the tested conditions.
The abstract reports that treated late-passage MSCs had reduced senescence-associated β-galactosidase activity, DNA damage markers and inflammatory cytokine secretion. Canonical MSC surface markers and genome stability were preserved, while proliferation, migration and tri-lineage differentiation recovered to levels comparable to early-passage MSCs. The authors call the treated cells partially reprogrammed MSCs, or prMSCs.
RNA-seq analysis indicated restoration of youthful gene expression and a stress-resilient, regenerative transcriptional program associated with repression of PI3K-Akt signaling. Combined RNA-seq and SNP array analysis supported retention of MSC identity and genome integrity without pluripotent conversion.
These findings suggest a potential approach to improving the potency and quality of MSC-based cell therapy products. They do not establish clinical efficacy or comprehensive safety.
The supplied text includes the complete abstract but ends during the Background section of the article body. Detailed methods and results are therefore unavailable for verification, including cell provenance, donor numbers, treatment dose and schedule, assay detection limits, sample sizes, effect sizes and statistical analyses. The excerpt also does not establish durability, generalizability across donors, in vivo efficacy or tumorigenicity outcomes.
Key Findings
- LNP-delivered circ-OSK transiently co-expresses OCT4, SOX2 and KLF4 in MSCs without genomic modification, according to the abstract.
- Circ-OSK reduced senescence-associated β-galactosidase activity, DNA damage markers and inflammatory cytokine secretion in senescent late-passage MSCs.
- Treated cells recovered proliferation, migration and tri-lineage differentiation to levels reported as comparable to early-passage MSCs.
- A validated ESRG-targeting ddPCR assay supported the authors' conclusion that circ-OSK alone did not induce pluripotent conversion under the tested conditions; the excerpt does not specify a detection limit.
- Canonical MSC surface markers were preserved, while combined RNA-seq and SNP array analysis supported retention of MSC identity and genome integrity.
- RNA-seq showed restored youthful gene expression and a stress-resilient, regenerative program associated with repression of PI3K-Akt signaling.
Methodology
The abstract describes a laboratory study of senescent late-passage MSCs treated with LNP-delivered circ-OSK, a circular RNA co-expressing OCT4, SOX2 and KLF4. Pluripotent conversion was assessed using a validated ESRG-targeting ddPCR assay. Reported readouts included senescence-associated β-galactosidase activity, DNA damage markers, inflammatory cytokine secretion, MSC surface markers, proliferation, migration and tri-lineage differentiation. RNA-seq and SNP array analysis assessed transcriptional changes, identity and genome integrity. The supplied body text ends during the Background section; cell provenance, donor numbers, controls, dose, treatment schedule, detailed assay validation, sample sizes and statistical methods cannot be verified.
Study Limitations
Only the abstract and part of the Background section are supplied. Detailed protocols, donor characteristics, sample sizes, effect sizes, statistical analyses and assay detection limits cannot be verified. The excerpt does not provide evidence sufficient to assess durability, donor generalizability, in vivo efficacy or tumorigenicity. No conflict-of-interest statement is included in the supplied text. Funding from the National Natural Science Foundation of China is documented; reagent vendors are not identified.
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