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SAN DIEGO--(BUSINESS WIRE)-- Rejuvenate Bio today announced publication of groundbreaking research in the peer-reviewed journal Cellular Reprogramming. The study, titled "Gene Therapy-Mediated Partial Reprogramming Extends Lifespan and Reverses Age-Related Changes in Aged Mice," reveals promising advancements in combating age-related diseases and extending lifespan through cellular rejuvenation. Aging is a complex process characterized by cellular dysregulation leading to deteriorated tissue and organ function. While aging cannot be prevented, interventions targeting cellular processes offer potential for mitigating its impact on health and lifespan in the elderly. Rejuvenate Bio's research focuses on partial reprogramming using the Yamanaka factors, specifically OCT4, SOX2, and KLF4 (OSK), to reverse age-related changes. In this study, systemically delivered adeno-associated viruses (AAVs) encoding an inducible OSK system were administered to 124-week-old male mice, equivalent to approximately 77 human years. The results demonstrated a remarkable 109% increase in median remaining lifespan compared to wild-type controls, along with improvements in various health parameters. Notably, frailty scores showed significant enhancements, indicating improved healthspan in treated mice. The active group also reported significant age-reversal in heart and liver tissues, as well as human keratinocytes, as indicated by DNA methylation clocks. To understand how OSK overexpression impacts human cells, OSK was also introduced into HEK001 keratinocytes obtained from a 65-year-old male patient's scalp. The researchers observed significant epigenetic age reversal in the treated keratinocytes compared to untreated or GFP-transduced cells. These findings, along with the data from mice, indicate that AAV-mediated gene therapy delivering OSK extends lifespan in mice while enhancing health parameters and reverses aging biomarkers in both mouse and human cells. “For the first time, we extend median remaining lifespan in extremely old wild-type mice, accompanied by improved health outcomes via systemic AAV-based partial reprogramming therapy,” said Noah Davidsohn, Ph.D., Chief Scientific Officer, Rejuvenate Bio. “Our study demonstrates profound age reversal in wild-type mice through exogenous OSK expression, evidenced by restoration of genomic methylation patterns characteristic of younger cells—a validated hallmark of age reversal. Our approach could potentially address the growing burden of age-related diseases in human populations, and we look forward to translating our findings into potential therapeutic interventions for aging-related conditions.” “This is the first published work to actually have epigenetic reprogramming extend overall lifespan in normal mice,” said Dan Oliver, Ph.D., CEO, Rejuvenate Bio. “The study’s analysis of human keratinocytes expressing exogenous OSK also revealed significant epigenetic markers of age reversal, suggesting a potential restoration of genetic networks to a younger, healthier state. These results may have important implications for the development of partial reprogramming interventions to reverse age-associated diseases in the elderly population.” About Rejuvenate Bio Rejuvenate Bio is a biotechnology company dedicated to developing novel gene therapies for chronic age-related diseases. Rejuvenate Bio has built a gene therapy pipeline with huge potential in chronic disease by utilizing clinically validated gene targets and a delivery approach that ensures well tolerated, durable expression. Founded on scientific research developed at the Wyss Institute at Harvard Medical School, Rejuvenate Bio has developed groundbreaking therapies to treat chronic age-related disease in both humans and animals. The company is headquartered in San Diego, CA. For more information, visit .

A new CRISPR interference (CRISPRi) model explores how the pioneer transcription factor FOXA controls human endoderm differentiation during liver development, and how the pioneer transcription factor OCT4 influences the behavior of pluripotent stem cells. The unexpected findings could influence future organoid and cell reprogramming studies. One of the important breakthroughs that made it possible to program or reprogram cell fate more efficiently and with higher fidelity in a dish was discovering how to make use of a small set of molecular cowboys called pioneer transcription factors (TFs). Every cell in our bodies has more than 200 transcription factors expressed inside, riding along the DNA helix instructing specific genes to activate and deactivate. During the early stages of fetal development, a small subset of "pioneer" TFs act inside our precursor cells driving them to make the mature cells that become parts of the spine, the heart, the liver, and so on. Identifying the key pluripotent pioneer TFs helped researchers learn how to make induced pluripotent stem cells from any type of adult cells, which could then be instructed to make other types of cells, thus forming organoids that can mimic functional organ tissue. Furthermore, tissue-specific pioneer TFs can directly reprogram one adult cell type into a targeted cell type without passing through a pluripotent state. Currently, there is considerable interest in producing therapeutic target cells from pioneer TF-mediated reprogramming of skin or other accessible somatic cells, as they hold great promise for personalized disease modeling and regenerative medicine. However, a major challenge is achieving sufficient gene repression of the original cell type, as inadequate repression often leads to the formation of "dead-end" cells or hybrid cells, thus limiting translational applications. Now a study published online Jan. 10, 2024, in Molecular Cell, reveals important new details about how pioneer TFs do their important jobs. "As we gain a more comprehensive understanding of the mechanisms underlying pioneer TF-mediated gene repression, it will greatly enhance the precise manipulation of cell fate in cellular programming and reprogramming," says Makiko Iwafuchi, PhD, a member of the Division of Developmental Biology and the Center for Stem Cell & Organoid Medicine at Cincinnati Children's. The first author, Satoshi Matsui, PhD, and Iwafuchi collaborated with Hee-Woong Lim, PhD, a co-senior author and a member of the Division of Biomedical Informatics, on the study. Until this study, most experts believed that pioneer TFs functioned primarily by activating genes to send cells toward their ultimate fates. However, scientists have learned that our genetic programming is packed with alternative pathways, which must be actively shut down. So how does the body ensure that precursor cells consistently follow the correct path? It turns out that pioneer TFs do more than push cells in the desired direction. When functioning correctly, these cowboys ride ahead and cut off alternative paths so that developing cells keep developing as intended. Who are these pioneers? The Cincinnati Children's team established a new CRISPR interference (CRISPRi) model to explore how the pioneer transcription factor FOXA controls human endoderm differentiation during liver development, and how the pioneer transcription factor OCT4 influences the behavior of pluripotent stem cells. They found that when FOXA function was disrupted, cells followed multiple development pathways. But when FOXA functioned normally, the cells stayed on track. This allowed the team to conclude that FOXA prevents alternative lineage and precocious gene expression. The team went on to show that FOXA gets help with repressing access to alternative pathways from another transcription factor called PRDM1 and other epigenetic repressors. Meanwhile in pluripotent cells, the pioneer transcription factor OCT4 performs a similar repression function by teaming up with a related transcription factor called PRDM14. The central role of FOXA and its ability to repress development pathways were unexpected and critical findings that could influence future organoid and cell reprogramming studies, Iwafuchi says. Finding a similar relationship occurring with OCT4 was an important further proof of concept because that transcription factor was already known to be among the pioneer TFs that enable reprogramming of somatic cells into pluripotent stem cells. Next steps Now that researchers have shown that two pioneer TFs coordinate with PRDM TFs to safeguard cell fate, it appears likely that other TFs have similar relationships. As these TF teams are identified, it may become possible to produce organoids and other engineered tissues in larger volumes with higher degrees of consistency and fidelity -- steps that will be important for scaling up the technology.

Scientists studied how the epigenetic landscape influences the binding of pioneer transcription factors, affecting access to DNA. Like thread tightly wrapped around a spool, DNA is wrapped around histones and packaged into structures called nucleosomes. Scientists at St. Jude Children's Research Hospital are exploring how a type of transcription factor called a pioneer transcription factor accesses DNA even when it is tightly wound. Their work revealed how the epigenetic landscape influences transcription factor binding. Problems with transcription have been implicated in numerous cancers, so this more detailed understanding of the process may aid in developing future therapeutics. The study was published today in Nature. The nucleosome packaging of DNA can physically block transcription factors that regulate gene expression from accessing their binding sites. Restricting access to DNA is an integral part of how transcription is regulated. However, pioneer transcription factors can bind to their target piece of DNA even within compacted chromatin and are also known to promote the binding of other transcription factors. Among pioneer transcription factors are the so-called Yamanaka factors which include Oct4 and are used to induce pluripotency (the ability to give rise to different cell types). How pioneer transcription factors access tightly wound DNA was unclear. To better understand the process, scientists at St. Jude used cryo-electron microscopy (cryo-EM) and biochemistry to investigate how Oct4 interacts with nucleosomes. "Building on prior work to understand the dynamic behavior of nucleosomes, we wanted to understand how other factors might utilize those dynamic changes to access chromatin," said corresponding author Mario Halic, Ph.D., St. Jude?Department of Structural Biology. "Oct4 did not bind where we anticipated it might -- rather than binding inside the nucleosome, we found that it bound a little bit outside." "One of the main findings is that epigenetic modifications can affect transcription factor binding and cooperativity," Halic added. "The existing epigenetic state of chromatin can determine how transcription factors will cooperatively bind to chromatin." The epigenetic impact Results show that the first Oct4 molecule binding "fixes" the nucleosome in a position that increases the exposure of other binding sites, thus promoting the binding of additional transcription factors and explaining transcription factor cooperativity.?They also found that Oct4 contacts histones, and these interactions promote chromatin opening and influence cooperativity. Their work also showed that modifications at histone H3K27 affect the positioning of DNA by Oct4. These findings explain how the epigenetic landscape can regulate Oct4 activity to ensure proper cell programming. Notably, the researchers used endogenous human DNA sequences instead of artificial sequences to assemble their nucleosomes. This allowed them to study the dynamic nature of the nucleosome, despite it being more challenging to work with. "In this work, we used real genomic DNA sequences to study transcription factors in the context of where they function," said first author Kalyan Sinha, Ph.D., St. Jude Department of Structural Biology. "This strategy allowed us to discover that the first binding event of Oct4 positions the nucleosomal DNA in a manner that allows cooperative binding of additional Oct4 molecules to internal sites. In addition, we observed exciting interactions with histone tails and have seen that histone modifications can alter those interactions. Together, these findings provide new insights into the pioneering activity of Oct4." "Histone modifications affect how DNA is positioned and how transcription factors can bind cooperatively," Sinha added, "which means in cells, if you have the same DNA sequence, different epigenetic modifications can result in different, combinatorial effects on transcription factor binding."