Bio-Reprogramming and Multi-Century Life Spans
by John G. Cramer
In my recent AV Column “Can We Cure Aging?” published in the May/June 2018 Analog, I described a new biotech method, developed by Oisin Biotechnologies of Seattle, for erasing many of the effects of human aging by clearing away the body’s accumulated burden of senescent cells. Senescent cells are damaged “zombie” cells that no longer function as intended, don’t divide, and produce toxic proteins that lead to a long list of health problems. Trials on mice have shown that using the Oisin technique increased the mean lifespan (or “healthspan”) of the test animals by over 20%. Related trials on human subjects are scheduled to begin soon.
However, even if we soon have a safe and efficient way of sweeping away all of the senescent cells from the human body, that will represent only a good start at dealing with the problem of human aging. The body’s remaining non-senescent cells would still bear the serious age-related environmental damage that accumulated over time. Here we list eight of the hallmarks of cell damage associated with aging: (1) stem cell exhaustion, (2) degraded intercellular communication, (3) deregulated nutrient sensing, (4) damaged or degraded mitochondria, (5) loss of DNA structural support, (6) poorly distributed DNA methylation, (7) loss of protein regulation, and (8) shortened telomeres. Even in mice in which all of the senescent cells have been cleared, these problems of age take their toll, and the test animals still die of age-related degeneration, living only about 20–25% longer than their untreated siblings.
This brings up a very important question: Is there any way of “resetting” aging cells to a younger state? We already know that this is possible in principle. When a man and a woman, perhaps in their forties, conceive a child, the mother contributes one of her cells (as an ovum) to the new individual, and somehow this particular cell has all of her accumulated environmental damage erased. The child starts life with new embryonic cells, not forty-year-old ones. How does this happen? There is now a body of research providing what seems to be the answer to this question: nature has provided a set of “reset” proteins that accomplish the task.
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In a 2006 paper, Takahashi and Yamanaka reported discovery of the “Yamanaka Factors,” four proteins designated by the acronyms OCT4, SOX2, KLF4, and c-MYC that are actively produced in the cells of embryos. They found that when these proteins were added to older mouse cells, the tested cells were transformed into seemingly brand-new stem cells that were able to develop into many different cell types. In a 2007 paper, Yu, et al, reported that aging human cells could be similarly transformed by adding to human somatic cell cultures a slightly different set of proteins: OCT4, SOX2, NANOG, and LIN28. In a 2019 paper, Sarkar, et al, a group at Stanford University, reported that they had combined these two sets of reset proteins into a six-protein cocktail (OCT4, SOX2, KLF4, c-MYC, LIN28 and NANOG, to which they assign the acronym “OSKMLN”). They found that when the OSKMLN cocktail is transfected (delivered inside the cell walls) into cell cultures with a daily application over a period of twelve days of treatment, a wide variety of aging human cell types are converted into embryonic stem cells. They also found that the same cell cultures could be “reprogrammed” to a younger but still functional state if the treatment process was halted after four days. They chose four days because that time is just before the observed “point of no return,” after which the treated cells revert to completely undifferentiated embryonic cells. In other words, they found that human cells could be rejuvenated.
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So how is this rejuvenation done? How does one put selected proteins into cells for such treatments? To answer this question, let’s discuss a bit of the mechanics of cell biology and look into how a cell actually produces a protein like those discussed above. If a cell wants to “express” (i.e., produce) a protein, it generates a transcription factor that has been coded to find within the library of the cell’s DNA sequences the particular “promoter region” (a unique identifying DNA base sequence) indicating the location of the instructions for producing the targeted protein. The transcription factor finds and lands on the DNA’s promoter region, then zips down the connected sequence of bases, producing a chain of mRNA (or messenger RNA) containing the information. The mRNA that has been generated finds its way to a ribosome (a protein-production factory located in the cell nucleus) and threads through the ribosome like a punched paper tape, delivering the instructions and causing the ribosome to assemble the requested protein. That protein is then released and does its requested job within or outside the cell.
What the Sarkar group did, in demonstrating that human cells can be “reset,” was to use the laboratory bio-machinery of RNA sequencing to mass-produce mRNA sequences for each of the six reset proteins of the OSKMLN cocktail. They then introduced this six-element cocktail of mRNA sequences into the cell interiors of their cell cultures, using several specialized commercial transfection compounds that were optimized for the different cell types investigated. The ribosomes of the cell interiors then used the mRNA to generate the desired rejuvenation proteins, and the proteins then went to work reprogramming the cells to a more youthful state.
The cell cultures that had been “reprogrammed” by this procedure were then tested to determine their biological state. The researchers found that in the aging cells tested, even those obtained from sixty- to seventy-year-old humans, seven of the eight hallmarks of aging listed above had been reset to the state expected for young cells. In this test, only item (8), the shortened telomeres, remained unchanged (and that deficiency is probably fixable by adding mRNA for the TERT protein to the OSKMLN cocktail). This test is a remarkable demonstration that it is possible, in the laboratory Petri dish and perhaps even in living organisms, to wipe away the damage of age and restore cells to a youthful state.
We note that Sarkar and several other members of the team have now formed a new biotech startup located in Mountain View, CA called Turn Biotechnologies, which plans to offer the application of the reset procedure to stem cells extracted from human patients, with the stem cells rejuvenated and then returned to the patient. They also have the more long-term goal of directly reprogramming and rejuvenating the cells in living human subjects.
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Thus, we have more new developments that, in the long view, encourage us to believe that the negative aspects of human aging can be cured, the cells of the human body can be rejuvenated, and that we may soon achieve John W. Campbell’s dream, expressed in an April 1949 editorial in Astounding, that we may move to a human life span that is measured in centuries rather than decades. How might this happen? Let’s consider some possible problems.
First, there is the problem of cancer. It is probable that aging cells become senescent and place a hard stop on cell division because they are damaged enough to be on the verge of becoming cancerous. Although the Sarkar work on cellular reprogramming did not produce any obvious malignancy in the cell cultures treated even after months of observation, it is possible that giving the same treatment to an aged living organism would move highly damaged cells from the precancerous to the cancerous category. Therefore, before attempting any in vivo cell reprogramming, perhaps one should take the precaution of clearing the patient of as many senescent or precancerous cells as possible. This now seems quite feasible, using the Oisin plasmid/liposome treatment that removes all cells attempting to express the senescence and malignancy marker proteins p16 and p53.
Another problem is that some forms of synthesized mRNA too closely resemble a retrovirus and are consequently attacked by antibodies in the cell cytoplasm, preventing reset protein production and generating a strong allergic reaction in the patient. It has been discovered that this problem occurs when the mRNA is over-synthesized during production and becomes double-stranded. It has also been found that this problem can be eliminated by restricting the concentration of magnesium chloride present during the mRNA synthesis process.
Then there is the problem of the mRNA delivery method. All of the commercial transfection compounds used in the Sarkar work to move the mRNA inside cell walls are highly toxic and could not be used in living organisms. However, there is an emerging solution. The Oisin delivery method used for plasmids (DNA rings) that I discussed in my May/June 2018 AV column could be applied with equal facility to deliver a payload of mRNA instead of plasmids. Essentially, the mRNA would be encased in a non-allergenic lipid bubble that merges with lipids forming the cell wall and delivers its payload inside.
Another problem is posed by the blood-brain barrier. The liposomes used for delivering plasmids or mRNA to the interior of cells would be largely excluded from the central nervous system by the blood-brain barrier. This makes treatment of age-related damage to neurons and other elements of the central nervous system a separate problem. It is likely that this problem can be solved by infusing the liposomes directly into the cerebrospinal fluid instead of the bloodstream. However, that treatment has not been tested and will remain an issue until such tests are performed. Particular care must be taken in this area, because over-rejuvenation of brain tissue might produce massive memory loss in the patient.
A final problem for in vivo treatment with the OSKMLN cocktail is that the point-of-no-return, as mentioned above, for treating different cell types with the reset proteins may differ significantly from one cell type to another. This could result in some cell types being over-programmed and over-reset to the point where they become embryonic, “forget” their function in the organism, and fail to perform essential tasks. Research is needed in this area, but the solution might be to limit the treatment to the earliest point-of-no-return for any cell type, or perhaps to design special liposomes than will only transfect mRNA to a particular cell type.
In summary, there are still some problems with this scheme for in vivo rejuvenation, but all of these problems appear to have solutions.
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The consequence of these biotech breakthroughs is that there is now a fairly unambiguous path leading to the rejuvenation of the human species. With more testing and technical progress, it now seems entirely possible that individuals currently alive, if they participate in current and future developments in anti-aging science, may live longer than previously thought possible.
“Induction of Pluripotent Stem Cells from Mouse Embryonic and Adult Fibroblast Cultures by Defined Factors”, Kazutoshi Takahashi and Shinya Yamanaka, Cell 126, 663 (2006); DOI 10.1016/j.cell.2006.07.024.
“Induced Pluripotent Stem Cell Lines Derived from Human Somatic Cells”, Junying Yu, et al., Science 318, 1917 (2007); DOI: 10.1126/science.1151526.
“Transient Non-integrative Nuclear Reprogramming Promotes Multifaceted Reversal of Aging in Human Cells,” Tapash Jay Sarkar, et al., (preprint), https://www.biorxiv.org/content/10.1101/573386v1.
John W. Campbell’s April 1949 ASF Editorial: https://www.dropbox.com/s/mp1n2re3vhf9heg/CampbellEd-v43n02-194904.pdf?dl=0;
Oisin Biotechnologies: https://www.oisinbio.com
Turn Biotechnologies: https://www.turn.bio
John G. Cramer’s 2016 nonfiction book describing his transactional interpretation of quantum mechanics, The Quantum Handshake—Entanglement, Nonlocality, and Transactions, (Springer, January 2016) is available online as a hardcover or eBook at: http://www.springer.com/gp/book/9783319246406. EBook editions of John Cramer’s hard SF novels Twistor and Einstein’s Bridge are available from the Book View Café co-op at: http://bookviewcafe.com/bookstore/?s=Cramer.
Copyright © 2019 John G. Cramer