Direct differentiation of tonsillar biopsy-derived stem cells to the neuronal lineage

DeepFreeze 3D-biofabrication for Bioengineering and Storage of Stem Cells in Thick and Large-Scale Human Tissue Analogs

3D bioprinting holds great promise for meeting the increasing need for transplantable tissues and organs. However, slow printing, interlayer mixing, and the extended exposure of cells to non-physiological conditions in thick structures still hinder clinical applications. Here the DeepFreeze-3D (DF-3D) procedure and bioink for creating multilayered human-scale tissue mimetics is presented for the first time. The bioink is tailored to support stem cell viability, throughout the rapid freeform DF-3D biofabrication process. While the printer nozzle is warmed to room temperature, each layer solidifies at contact with the stage (-80 °C), or the subsequent layers, ensuring precise separation. After thawing, the encapsulated stem cells remain viable without interlayer mixing or delamination. The composed cell-laden constructs can be cryogenically stored and thawed when needed. Moreover, it is shown that under inductive conditions the stem cells differentiate into bone-like cells and grow for months after thawing, to form large tissue-mimetics in the scale of centimeters. This is important, as this approach allows the generation and storage of tissue mimetics in the size and thickness of human tissues. Therefore, DF-3D biofabrication opens new avenues for generating off-the-shelf human tissue analogs. It further holds the potential for regenerative treatments and for studying tissue pathologies caused by disease, tumor, or trauma.

Anti-aging effect of β-carotene through regulating the KAT7-P15 signaling axis, inflammation and oxidative stress process

Background

Research on aging is growing as the elderly make up a greater share of the population, focusing on reversing and inhibiting the aging process. The exhaustion and senescence of stem cells are the fundamental drivers behind aging. β-Carotene has been depicted to have many biological functions, and we speculate that it may have an anti-aging effect.

Methods

Firstly, the anti-aging property of β-carotene was investigated in vitro using mesenchymal stem cells (MSCs) induced by H₂O₂. The anti-aging effect was characterized using Western-bloting, confocal laser scanning microscopy, indirect immunofluorescence, and immunohistochemistry. The anti-aging property was also tested in vivo using aged mice.

Results

The in vitro experiment revealed that β-carotene could relieve the aging of MSCs, as evidenced by a series of aging marker molecules such as p16 and p21. β-Carotene appeared to inhibit aging by regulating the KAT7-P15 signaling axis. The in vivo experiment revealed that β-carotene treatment has significantly down-regulated the aging level of tissues and organs.

Conclusions

In this work, we explored the anti-aging effect of β-carotene in vivo and in vitro. The experimental results indicate that β-carotene may be an important potential anti-aging molecule, which can be used as a drug or in functional food to treat aging in the future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00389-7.

Basic Fibroblast Growth Factor Induces Cholinergic Differentiation of Tonsil-Derived Mesenchymal Stem Cells

BACKGROUND

Mesenchymal stem cells (MSCs) are considered a potential tool for regenerating damaged tissues due to their great multipotency into various cell types. Here, we attempted to find the appropriate conditions for neuronal differentiation of tonsil-derived MSCs (TMSCs) and expand the potential application of TMSCs for treating neurological diseases.

METHODS

The TMSCs were differentiated in DMEM/F-12 (Dulbecco's Modified Eagle Medium/Nutrient Mixture F-12) supplemented with various neurotrophic factors for 7-28 days to determine the optimal neuronal differentiation condition for the TMSCs. The morphologies as well as the levels of the neural markers and neurotransmitters were assessed to determine neuronal differentiation potentials and the neuronal lineages of the differentiated TMSCs.

RESULTS

Our initial study demonstrated that DMEM/F12 supplemented with 50 ng/mL basic fibroblast growth factor with 10 μM forskolin was the optimal condition for neuronal differentiation for the TMSCs. TMSCs had higher protein expression of neuronal markers, including neuron-specific enolase (NSE), GAP43, postsynaptic density protein 95 (PSD95), and synaptosomal-associated protein of 25 kDa (SNAP25) compared to the undifferentiated TMSCs. Immunofluorescence staining also validated the increased mature neuron markers, NeuN and synaptophysin, in the differentiated TMSCs. The expression of glial fibrillar acidic protein and ionized calcium-binding adaptor molecule 1 the markers of astrocytes and microglia, were also slightly increased. Additionally, the differentiated TMSCs released a significantly higher level of acetylcholine, the cholinergic neurotransmitter, as analyzed by the liquid chromatography-tandem mass spectrometry and showed an enhanced choline acetyltransferase immunoreactivity compared to the undifferentiated cells.

CONCLUSION

Our study suggests that the optimized condition favors the TMSCs to differentiate into cholinergic neuron-like phenotype, which could be used as a possible therapeutic tool in treating certain neurological disorders such as Alzheimer's disease.