We present here a recent example of a graduate published dissertation, being a Review paper on the subject of Plant Exosomes.
As the students at the Panama College of Cell Science are coming to learn, the topic of Exosomes has exploded onto the stem cell biologics landscape over the last year or so.
First, researchers were isolating and characterizing exosomes in adult stem cell sources like bone marrow, fatty tissue aspirates, and amniotic fluids. Then the hunt was on for looking at exosomes derived from various adult stem cell cultures, which is still developing at a very fast pace as researchers learn how to manipulate stem cells in culture using different exosomes.
In this very cutting edge Review, Tong Shen M.D. (PhD, Panama College of Cell Science) reviews the literature and our current knowledge concerning plant exosomes- particularly from Coconut (Cocos Nucifera). Her paper characterizes the botanical exosomes and compares their activity to adult stem cell exosomes in stimulating stem cells in culture, demonstrating thereby, that plant exosomes can play a role in human regenerative medicine.
We present this paper as an excellent example of the kinds of work our graduate students are doing here at the Panama College of Cell Science, and we are proud to display their contributions to advancing our scientific knowledge of stem cell biologics from time to time.
The paper is titled: “Characterization and Comparison of Exosomes Found in Stem Cell Cultures to Those Found in Plant Botanicals Especially Cocos Nucifera” by Tong Shen and can be cited as follows: Shen, Tong (2021): Characterization and Comparison of Exosomes Found in Stem Cell Cultures to Those Found in Plant Botanicals Especially Cocos Nucifera. Figshare. Thesis. https://doi.org/10.6084/m9.figshare.14658351.v1
The Abstract from the paper states its core findings: “While extensive information is published regarding human exosomes derived from adult stem cell cultures, limited publications are available on exosomes extracted from plant botanicals. This review characterized that similar to exosomes derived from adult stem cultures, exosomes extracted from plant botanicals such as cocos nucifera (coconut) water have demonstrated similar biological activities yet through exerting cross-species plant-to-human exosome-mediated intercellular communication and development. Plant exosomes, characterized by their differential advantages compared to mammalian-derived exosomes, are considered as more ideal exosomal sources regarding its scalability and cultivation convenience. Due to smaller exosomal size, coconut water in particular is characterized with more efficient absorption/uptake by human cells and delivery of exosomal contents (e.g., mircroRNAs) upon exerting biological activity against human cells, which potentially enlighten future applications of coconut water exosome-based therapeutics in humans.”
Some terrific take away points from the paper include the following excerpts:
-The purpose of this review is to characterize and compare exosomes extracted from plant botanicals, especially coconut water, to exosomes derived from adult stem cell cultures found in AF. This review is to elucidate (1) whether plant exosomes could potentially substitute mammalian exosomes by characterizing and comparing between both exosomal sources, and (2) whether plant exosomes can exert biological activities in humans (e.g., human cell proliferation, tissue regeneration, differentiation) through cross-species plant-to-human exosome-mediated intercellular communication
-Exosomes can be isolated from collecting conditioned media (supernatant) of cell cultures followed by serial centrifugations (300g for 10 min, 2,000g for 10 min and 10,000g for 30 min at 4 °C). The supernatant from the 10,000g centrifugation was ultracentrifuged at 100,000g for 70 min at 4 °C to collect the exosome-enriched fraction (pellet). The preferred isolation technique of exosomes derived from adult stem cell cultures found in AF is size-exclusion chromatography (qEV), which has generated higher yield of exosomes, lower protein contamination, lower sheer stress on EVs, and higher efficiency with approximately 15 minutes per preparation.
– While exosomes that derived from adult stem cell cultures of different origins might differ in exosomal contents and their corresponding biological functions on target recipient cells, exosomes by themselves can exert biological functions similar to the adult stem cell cultures that they have derived from.
-Indeed, plant cell culture-derived active cosmetic ingredients with more enriched exosomes have revealed stronger activities than the plant extracts obtained by the traditional methods that are applied by majority of the cosmeceuticals
-Moreover, plant exosomes are characterized of their additional benefits including their tissue-specific targeting activities with significantly lower allergenic effects and immunogenicity.
-Plant exosomes already are surprisingly utilized by humans: This is demonstrated by plant exosomal miRNAs that are not only found to be present human specimens but also are seized by human GI tract, regulating cross-kingdom gene expression in humans and cellular processes through dietary intake.
-And possibly the most important observation: Interestingly, the average increase in miRNAs has found to be approximately 20 times higher in immature coconut water than in mature coconut water, with the highest degree of change in miR528-5p for 112 folds higher, demonstrating biological process of possibly regenerative potentials in immature coconut. The immature (young) coconut resembles the young mouse from the heterochronic pair in the old-young mice parabiosis experiment in which the young mouse contains the young serum that promote cell proliferation such that the young coconut water is characterized with the much higher exosomal miRNA-mediated biological processes that promote its proliferation.
-Overall, this review has demonstrated: [that] plant exosomes, especially coconut water, are comparable to exosomes derived from adult stem cell cultures by characterizing with similar exosomal structures and exosomal compositions as well as exerting similar biological activities against human cell proliferation, differentiation and regeneration in human systems, at least revealed by the in vitro systems.
The full paper, which presents an excellent starting point for anyone beginning the study of plant exosomes, can be downloaded HERE:
Tong Shen Plant Exosomes Review Paper
The Panama College of Cell Science continues to offer the only 3 year online PhD degree in stem cell biology in the world. We have been offering our PhD stem cell biology program since 2005, and for 16 years, we have continued to upgrade our courses and Curriculum to stay on the very top of this new field. We just recently added our latest course to the Panama College of Cell Science Curriculum effective as of September 1, 2021: Exosomes and the Rise of Birth Tissues, described here: https://panamacollegeofcellscience.org/2021/02/06/new-exosomes-course-added-at-panama-college-of-cell-science/
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