SAN DIEGO–(BUSINESS WIRE)–
The NIH’s National Heart, Lung, and Blood Institute has awarded Allele Biotechnology and Pharmaceuticals (“Allele”) a Phase 1 SBIR grant to develop a novel manufacturing system to produce stem cell-derived human tissue and cells for clinical therapy. By increasing the scale of production and reducing the cost of manufacturing, Allele is confident that this system will overcome a considerable roadblock for clinical applications of stem cells, which is to produce a sufficient amount of therapeutic material at a manageable cost.
At the core of translating this potentially game-changing technology into medically-beneficial applications is the use of induced pluripotent stem cells (iPSCs), which hold unprecedented promise of providing any type of immune-matched cells of unlimited quantity. Allele has already developed a patented method of reprogramming somatic cells into iPSCs, secured industrial licensees using this technology, and initiated cGMP procedures for clinical applications.
Further moving iPSCs into commercially viable clinical cell therapies still requires overcoming one major barrier: the prohibitive cost of manufacturing iPSC-derived cells, mostly due to the need of expensive clinical-grade growth factors and cytokines. For example, the estimated cost of the growth factors and cytokines needed to produce a typical transfusion of platelets is $87,252.
Ultimately, Allele’s goal is to create clinical-grade iPSCs and control their differentiation into specific cell types at a scale large enough to satisfy the clinical demand. “We have been diligently working on removing the use of protein factors through our own proprietary protocols to generate many clinically-relevant cell types, including beta cells, mesenchymal stem cells, neural progenitor cells, oligodendrocytes, liver, and heart cells,” said Dr. Jiwu Wang, Allele’s CEO and the Principle Investigator of the new NIH grant. “By developing a recombinant protein-independent, real-time adjusted culture system under this project, we are confident that—as many groundbreaking technologies such as genome sequencing have done—the manufacturing process will mature and the costs will come down to eventually benefit everybody.”
Allele’s plan gained trust from the NIH scientific review panel, which gave it a near-perfect score. With this funding, Allele’s researchers will move even faster towards the goal of bringing iPSC products to clinical applications. Successful efforts will also likely provide a vehicle for genome-editing technologies such as CRISPR to be delivered into patients.
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With acceptance of stem cell therapies growing, so have controversies surrounding regulations.
Desperate to heal sports injuries, top professional athletes have been known to pay tens of thousands of dollars for experimental stem cell treatments that many used to find controversial. But now, stem cell therapies have become more mainstream and are no longer limited to professional athletes. Stem cell clinics offer both medical and non-medical treatments with claims of improving aesthetics and quality of life.
One recent study found over 400 websites – with the largest portion in the United States – advertising stem cell-based therapies (1); another found over 570 U.S. clinics offering stem cell interventions (2), giving more evidence that the market for stem cell therapies in the U.S. is growing at an accelerated rate. Yet these therapies are too often based on unfounded claims and lack proper clinical trials or authorized regulation. Despite what some clinics claim, very few stem cell treatments are currently available that are actually approved by the Food and Drug Administration (FDA). Hematopoietic stem cells harvested from bone marrow are routinely used in transplant procedures to treat patients with cancer or other blood or immune system disorders. Banking of umbilical cord blood is FDA-regulated and its use is approved for certain indications. Otherwise, consumers should be wary of claims by stem cell clinics implying FDA-approval.
So why aren’t more FDA-approved stem cell therapies available?
The FDA has strict regulations on using stem cell products in humans. In most cases, stem cell-based products are categorized the same way as pharmaceutical drugs. Therefore, each new therapy must go through a rigorous process including pre-clinical animal trials, phased clinical studies, and pre-market review by the FDA prior to offering the treatment in the clinic.
And with stringent regulatory requirements comes prohibitive costs. Research animals, Phase I-III clinical trials, and the regulatory demands for good manufacturing practice (GMP) labs result in an extraordinarily costly process that may hinder the progress of new therapies. The cost of developing a new drug has even been estimated to reach billions of dollars.
Nevertheless, a complete lack of regulation of stem cell therapies – as is seen in many of the stem cell clinics springing up worldwide – is clearly problematic. Alarmingly, many clinics advertise claims related to medical diseases for which there is no scientific consensus that supports their safety or efficacy. Premature commercialization of unproven therapies not only puts patients at risk, but also jeopardizes the credibility of still-developing stem cell products.
One of the most exciting outlooks for stem cell therapy is the prospect of using one’s own stem cells for personalized medicine. Should the development of an autologous stem cell product really be regulated the same way as a pharmaceutical drug, which is aimed at treating huge populations of people? If not, how should stem cell products be regulated?
In an effort to make the transition of novel stem cell products to the clinic more seamless, some countries have made significant changes in regulations. For instance, in 2014, Japan broke out a separate regulatory system for stem cell products that softened legislation dramatically to require only limited safety and efficacy data. Some argue that countries with softer regulations and less stringent safety and efficacy milestones, such as Japan, have poised themselves to become the likely pioneers in the field of regenerative medicine.
Regulatory frameworks for the clinical application of stem cell products are still evolving in most countries, including the U.S. In March, the Reliable and Effective Growth for Regenerative health Options that improve Wellness (REGROW) Act was introduced to congress. This change in legislation would remove some of the regulatory hurdles that hinder the progress of biologic therapies.
Regardless, the FDA needs to establish a more reasonable regulatory system that can evaluate the safety and efficacy of stem cell products in a more efficient manner.
1. Berger, I., et al., Global Distribution of Businesses Marketing Stem Cell-Based Interventions. Cell Stem Cell, 2016. 19(2): p. 158-62.
2. Turner, L. and P. Knoepfler, Selling Stem Cells in the USA: Assessing the Direct-to-Consumer Industry. Cell Stem Cell, 2016. 19(2): p. 154-7.
The CRISPR gene-editing technology is taking the scientific world by storm, but researchers are still uncovering the platform’s potential and pitfalls.
The “Democratization” of Gene Editing
The idea of modifying human genomes using homology directed repair (HDR) has been around for decades. HDR is a widely-used repair mechanism to fix double-strand breaks in the cell’s DNA. By supplying an exogenous, homologous piece of DNA to the cell and increasing the probability of HDR occurring, changes in the DNA sequence can be introduced to the targeted area.
Some of the first gene editing platforms taking advantage of HDR used engineered endonucleases such as zinc finger nucleases (ZFNs) and transcription activator like effector nucleases (TALENs). Both ZFNs and TALENs required a custom protein to target a specific DNA sequence, making them pricey and very difficult to engineer. The more recently developed CRISPR/Cas9 platform works differently: instead of using a protein, the Cas enzyme uses a small guide RNA to locate the targeted DNA, which is then cut. CRISPR is more low tech and “user-friendly” than other platforms, as users are no longer required to do the onerous chore of protein engineering. Now, the ability to modify genomes can be done without extensive training or expensive equipment. CRISPR can be used for knocking out genes, creating reporter or selection genes, or modifying disease-specific mutations—by practically anyone with basic knowledge of molecular biology.
The CRISPR Revolution
Because of its relative simplicity and accessibility, it is no wonder that life scientists from all over the world are eager to incorporate CRISPR into their research. One of the most remarkable things about CRISPR technology is how quickly its popularity has allowed the platform to evolve. The discovery revealing that CRISPR can be used for RNA-programmable genome editing was first published in 2012 (1). Since then, about 2,000 manuscripts have been published including this technology and millions of dollars have been invested into CRISPR-related research and start-up companies. Scientists have developed a myriad of applications for CRISPR, which can be used in practically any organism under the sun. The popularity and progress of gene editing promises revolutionary advancements in virtually every scientific field: from eradicating disease-carrying mosquitoes to creating hypoallergenic eggs and even curing genetic diseases in humans.
There is no doubt that CRISPR has enormous potential – the widespread interest and rapid progress are evidence of that. The main reason CRISPR has been so widely adapted is because development and customization is way less labor-intensive and time-consuming than previous methods. But material preparation is a miniscule part of the CRISPR platform. Contrary to popular belief, just because CRISPR is easier to use than other methods of gene editing, it is not “easy.”
Hitting the Bull’s-Eye
To understand the limitations of this gene editing technology, it’s important to understand more about how CRISPR works. The CRISPR/Cas9 system functions by inducing double-strand breaks at a specific target and allowing the host DNA repair system to fix the site of interest. Cells have two major repair pathways to fix these types of breaks, Non-Homologous End Joining (NHEJ) and homology directed repair (HDR). NHEJ is faster and more active than HDR and does not require a repair template, so NHEJ is the principle means by which CRISPR/Cas9-induced breaks are repaired. If the editing goal is to induce insertions or deletions through NHEJ to cut out a part of a gene, then using the CRISPR platform is less complicated. But directing CRISPR to correct a gene with exogenous DNA does not work very well, as the rate of HDR occurring at the site of interest is often very low, sometimes less than 1%. For precise genome-editing through CRISPR, it is essential to have HDR while minimizing damaging NHEJ events.
Increasing the rate of HDR is not trivial. Recent research has shown that the conditions for the two repair pathways vary based on the cell type, location of the gene, and the nuclease used (2). Besides, optimizing CRISPR to better control HDR versus NHEJ events is only half the battle. One of the greatest challenges in using CRISPR is to be able to quickly and accurately detect different genome-editing events. Many scientists measure changes by sequencing. A more sophisticated method is to use droplet digital PCR (ddPCR) (3), but many labs have limited accessibility to ddPCR systems. After screening multiple clones and detecting the desired genetic edit comes what is usually the most laborious and time-consuming step: pure clonal isolation. Because each individual cell is affected by CRISPR independently, isogenic cell lines must be established.
CRISPR has become the gold standard for many scientists now that the potential to perform gene editing has become so universal. Top journals expect isogenic lines for characterizing genes and mutations, and many researchers feel pressured to include such experiments to stay competitive in grant proposals. Moreover, a federal biosafety committee has recently approved the first study in patients using this genome-editing technology. To keep up with the pace of this rapidly moving field, significant improvements in CRISPR technology need to be made.
First, a better grasp of the basic principles behind CRISPR is likely to lead to improvements in targeting and efficiency. For example, understanding how the cell type, locus, and genomic landscape affect the targeting and cutting of Cas9 could lead to higher efficiencies of HDR. Similarly, engineering Cas9 and the guide RNA to maximize on-target activity could also accelerate the technology’s success. Screening the ability of the guide RNA to target the intended sequence can be performed in vitro by assessing the Cas9-mediated cuts on a PCR-amplified fragment of DNA; this method often gives a good indication of what to expect in cells. Another hindrance to CRISPR technology is that currently, all methods to detect genome changes require destruction of the cells of interest. Development of an assay to detect chromosomal changes in live cells – reminiscent of live-cell RNA detection – would immensely improve the processes of clonal screening and isolation.
Besides the technical challenges that come with maximizing on-target edits is that Cas9 frequently has off-target effects, producing insertions or deletions at unintended sites. Online algorithms can predict where some of these cuts are likely to occur, but currently, there is no efficient method to identify all possible off-target sites (4). To complicate things further, no two human genomes are identical. Due to genetic variation, predicting off-target effects based on reference genomes remains a challenge. Because so much of the hype around CRISPR surrounds the potential to treat human diseases, it is imperative to make sure that CRISPR does not introduce detrimental changes elsewhere in the genome before therapeutic use in humans. Standard screening methods and biological assays need to be established to robustly assess potential damage done to other sites in the genome and to measure its impact on cell function and mutagenesis.
Despite its shortcomings, the hub of activity surrounding CRISPR has been astounding. And with the force of thousands of scientists working on this technology, the possibilities for the future of CRISPR are boundless.
- Jinek, M., et al., A programmable dual-RNA-guided DNA endonuclease in adaptive bacterial immunity. Science, 2012. 337(6096): p. 816-21.
- Miyaoka, Y., et al., Systematic quantification of HDR and NHEJ reveals effects of locus, nuclease, and cell type on genome-editing. Sci Rep, 2016. 6: p. 23549.
- Hindson, B.J., et al., High-throughput droplet digital PCR system for absolute quantitation of DNA copy number. Anal Chem, 2011. 83(22): p. 8604-10.
- Stella, S. and G. Montoya, The genome editing revolution: A CRISPR-Cas TALE off-target story. Bioessays, 2016. 38 Suppl 1: p. S4-s13.
Last year Allele dedicated a new building space for cleanroom operations to provide a cell banking service for personalized medicine. This facility will be the center of current Good Manufacturing Practice (cGMP) production of human induced pluripotent stem cells (iPSCs) using Allele’s proprietary synthetic mRNA platform. Over the past three months, progress to get the facility up and running has been substantial. Our facility includes four main modules: the reception area and doctors’ offices, a Fibroblast Isolation and Maintenance room, a Reprogramming and iPSC Maintenance room, and a Quality Control room. Air handling, which is a major component of the environmental control system, has been installed and validated. Equipment such as biosafety cabinets, incubators, and refrigerators have been installed and qualified, as well as equipment for performing essential quality control steps. To standardize personnel-related steps of cGMP processing, we have prepared rigorous SOPs and have extensively trained individual manufacturing operators. Overall, we are enthusiastic about the facility’s progress and are committed to delivering the best possible service as the industry leader in iPSC banking.
Three years since our flagship fluorescent protein was published in Nature Methods, mNeonGreen is still shining bright. mNeonGreen is a green-yellow fluorescent protein that has been shown to be highly useful in optical assays from general imaging to FRET to super resolution microscopy applications and more.
What makes this fluorescent protein such a hit among researchers?
Since the cloning of green fluorescent protein (GFP) over 20 years ago, fluorescent proteins have become a standard research tool, enabling labeling and imaging of individual proteins within a cell in real time. To make these probes brighter, faster folding, and to cover a wider range of the visible spectrum, new fluorescent proteins are continually being developed. mNeonGreen was engineered by scientists at Allele Biotech from a protein isolated from Branchiostoma lanceolatum, a marine invertebrate, and is the brightest monomeric green-yellow fluorescent protein ever characterized.
Perhaps the most common use of fluorescent proteins today is genetically fusing them to a protein of interest to image protein localization. Unfortunately, many researchers are unaware that many fluorescent proteins – such as GFP – are prone to forming noncovalent dimers, which can lead to significant artifacts. True monomeric fluorescent proteins such as mNeonGreen are less likely to affect the localization, dynamics, or normal behavior when fused to proteins of interest.
For quantitative imaging and live-cell imaging applications, arguably the most critical parameters to consider when choosing fluorescent proteins are brightness and photostability. mNeonGreen has high fluorescence brightness, so less light can be delivered to the cells to collect ample signal intensity, resulting in less phototoxicity. mNeonGreen also has superior photostability, meaning it can undergo many excitation-emission cycles before photobleaching occurs. Because of these properties, mNeonGreen has been shown to be very effective as a fluorophore in fluorescence resonance energy transfer (FRET) – both as an acceptor and a donor.
The community of biologists taking advantage of super-resolution fluorescence microscopy (Nobel Prize in Chemistry 2014) is rapidly growing. But the ability to resolve cellular structural features depends on the chosen fluorophore’s brightness, labeling density, and the stability of the dark state. mNeonGreen is not only extraordinarily bright, but also can be driven into a temporary dark state by light irradiation, making it a useful tag for single-molecule super-resolution imaging of proteins.
Researchers around the world continue to develop novel applications for mNeonGreen. Recently, mNeonGreen was used to create a genetically encoded voltage sensor that can be used to image subcellular changes in electrical activity. Researchers fused mNeonGreen to a light-sensitive ion channel in neurons, linking mNeonGreen fluorescence with the membrane voltage to create an optical readout for neuronal activity with unprecedented speed and accuracy.
Choosing an appropriate fluorescent protein for an assay is often a source of confusion for researchers. In many cases, the selection of a fluorescent protein is motivated by convenience (e.g., availability of the construct) rather than its performance for a given assay. If mNeonGreen seems like the right fluorescent protein for your assay, we at Allele Biotech have made it easy and painless for researchers to get their hands on it. Laboratories can license mNeonGreen for full use at a low cost.
Questions about licensing or whether mNeonGreen is really right for your lab? Contact email@example.com.
“A bright monomeric green fluorescent protein derived from Branchiostoma lanceolatum.”
Shaner, N. C., Lambert, G. G., Chammas, A., Ni, Y., Cranfill, P. J., Baird, M. A., Sell, B.R., Allen, J.R., Day, R.N., Davidson, M.W., Wang, J.
2013 Nat Methods, 10(5), 407-409. doi:10.1038/nmeth.2413
“High-speed recording of neural spikes in awake mice and flies with a fluorescent voltage sensor.”
Gong, Y., Huang, C., Li, J. Z., Grewe, B. F., Zhang, Y., Eismann, S., & Schnitzer, M. J.
2015 Science, 350(6266), 1361-1366. doi:10.1126/science.aab0810
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