Genetic Engineering to Turn Back the Clock on Aging Cells
Scientists are employing gene editing technology to reverse cell aging. First they identified genes which alter gene expression in human fibroblasts cells.
Researchers then inserted FOXO3, a gene known for activating longevity pathways, which enhanced cells’ abilities to resist senescence and reverse age-related diseases. Finally, these senescence-resistant cells were administered intravenously into elderly cynomolgus macaques where their rejuvenating stem cells unleashed sharper cognition, stronger bones, and revived reproductive health without any negative side effects.
Gene editing
Genetic engineering (also referred to as gene editing) is the process of altering DNA to alter specific characteristics in an organism in a desired way, from changing one base all the way up to deleting or inserting entire regions of DNA. These techniques have many uses across agriculture, environmental conservation and medicine industries.
CRISPR-Cas9 genome editing technology works like molecular scissors, cutting organism’s DNA at precise locations to add, delete or replace genetic material (Figure 1). This method of genetic engineering is faster, cheaper and more accurate than older techniques; currently used in numerous research projects worldwide.
Scientists use gene editing to develop gene therapies, treatments that target diseases with genomic origins. Gene therapies may treat single or multiple ailments in one individual patient and can be divided into two categories: germline therapy and somatic therapy; the former modifies reproductive cells such as sperm and eggs to affect future generations, while somatic therapies only have effects that remain with those receiving them; they do not pass onto future generations.
Scientists working to reverse aging through gene editing must first identify and manipulate the genes that contribute to its effects, then alter or delete them to extend cell life and promote healthy aging. Researchers currently utilizing CRISPR-Cas9 genome editing tool to modify genes associated with cell growth and signaling and thus increase human and animal lifespan by improving function while eliminating harmful mutations.
Although gene editing provides many advantages, it also raises ethical and regulatory issues. While using gene editing in food crops is legal in the US government requires bioengineered products containing detectable levels of modified DNA be labeled accordingly; each case will be investigated to ascertain if these requirements have been fulfilled.
Transcription factors
TFs are protein molecules that manage when and how genes are activated or deactivated in cells. They do this by binding to specific DNA sequences or proteins associated with them and changing their activity; in turn affecting production of RNA that’s used to make proteins and other cell functions. As people age, gene activity levels change, contributing to diseases. Reducing or reversing this change could potentially help people live longer, healthier lives – scientists must study transcription factor’s impact on human health as a means for improving this aim.
Identification of DNA sequences that transcription factors (TFs) recognize requires complex laboratory techniques, including chromatin immunoprecipitation and DNA microarrays, as well as an understanding of their interactions. Utilizing computational methods, potential binding sites (TFBSs) may be predicted based on sequence conservation, DNA structural properties and recognition motifs recognized by specific types of TFs; this allows prioritizing potential binding sites for experimental validation; other techniques like EMSA or yeast monohybrid can verify direct interaction between TF and target DNA sequence.
Researchers studying the role of transcription factors (TFs) in aging use RT-PCR and qPCR to examine their expression patterns in various tissues and cell types, then identify which TF-DNA interactions play the most vital roles for gene function.
Transcription factors (TFs) have the ability to recognize DNA motifs found across several genes and bind with them in complex ways, which allows them to activate or repress genes based on various signaling events like light exposure and growth factor treatment. These interactions allow TFs to activate or repress specific genes depending on these signals – whether light exposure or growth factor treatment is an example.
Researchers discovered that the activity levels of various transcription factors change with age, contributing to cell senescence and related illnesses such as dementia. They then conducted studies on living mice to alter these factors’ levels – increasing one transcription factor (EZH2) caused aged fibroblasts to behave like younger cells again reducing fat buildup in livers while improving glucose tolerance as well as reverse some negative consequences of aging such as liver damage and cancer.
Chemicals
Researchers have recently demonstrated how chemicals can reverse the effects of aging and extend the lives of living things. This method relies on chemical changes occurring at both genome and transcriptome levels – changes which revert cells back into their younger state, giving an appearance of youngerness and healthiness to people over time. Researchers are exploring whether gene-editing techniques and chemical remedies can be used as therapies against diseases associated with aging.
Scientists recently devised a “transcriptomic aging clock” to demonstrate that chemical cocktails can suppress genes linked to cell senescence and thus slow its progress by three years in less than one week without altering its identity or altering cell identity. This research represents the first instance where rejuvenation through chemical means could be accomplished on human cell lines.
To pinpoint which genes were contributing to these anti-aging effects, the team conducted gene set enrichment analysis (GSEA) on chemical cocktails and OSK(M)-induced iPSCs using KEGG, HALLMARK gene sets and Reactome pathways as inputs; GSEA was then run with 5000 permutations trials until results indicated high correlations between genes induced by chemicals and expression signatures associated with senescence.
Human trials
Scientists have long suggested that loss of epigenetic information–chemical tagging patterns on DNA that control which genes are activated or deactivated–is one cause of aging. David Sinclair from Life Biosciences in Boston has long studied this idea, and recently claimed to have successfully reversed vision loss in mice using “partial epigenetic reprogramming.” ER-100 trials will test this strategy with human subjects.
Sinclair’s laboratory had used CRISPR, a tool that acts like molecular scissors to cut and disable sections of DNA, to boost neural stem cells from mice that had become dormant with age, which then stimulated production of new neurons. While results were encouraging, Sinclair believed the process needed to be more comprehensive if reverse aging were to happen in humans; so he developed a functional screening method to identify all genes within humans’ genome that may improve or even reactivate old stem cells.
To test their approach, his team genetically engineered mesenchymal progenitor cells to express geroprotective gene FOXO3 in a 44-week study with cynomolgus macaques. After injection into their eyes, these SRCs, known as stem cell reprogrammed for longevity (SRCs) dramatically rewrote biological clocks while significantly improving multiple organ systems – immune and skeletal systems strengthening while metabolic markers of aging decreased significantly compared to controls; scientists also discovered SRCs reactivated older cells by increasing cell proliferation causing them to become more robust compared with controls.
Sinclair’s approach is much more ambitious than anything previously attempted in terms of pro-longevity treatments; his gene therapy uses three proteins called Yamanaka factors that he claims will reset epigenetic information to more youthful states and has begun testing it with patients suffering from glaucoma and non-arteritic anterior ischemic optic neuropathy, or NAION.
