Polymerized Laminin-521: A Feasible Substrate for Expanding Induced Pluripotent Stem Cells at a Low Protein Concentration

Wisent Somatic Cells Resist Reprogramming by the PiggyBac Transposon System: A Case Study Highlighting Methodological and Conservation Hurdles

The European wisent (Bison bonasus), an iconic yet genetically vulnerable species, faces ongoing conservation challenges due to a restricted gene pool. Advances in induced pluripotent stem cell (iPSC) technology offer promising prospects for preserving and restoring genetic diversity in endangered species. In this study, we sought to reprogram wisent somatic cells into iPSCs using the PiggyBac transposon system, a non-viral method known for being successfully applied in bovine species. We applied a six-factor reprogramming cocktail (OCT4, SOX2, KLF4, LIN28, c-MYC, NANOG) alongside small-molecule enhancers to fibroblasts isolated from adult wisent tissue. While initial colony formation was observed, the reprogrammed cells exhibited limited proliferation and failed to maintain stable pluripotency, suggesting intrinsic barriers to complete reprogramming. Despite optimizing culture conditions, including hypoxia and extracellular matrix modifications, the reprogramming efficiency remained low. Our findings indicate that wisent somatic cells may require alternative reprogramming strategies, such as new-generation delivery systems and epigenetic modulators, to achieve stable iPSC lines. This study underscores the need for species-specific optimization of reprogramming protocols and highlights the potential of emerging cellular technologies for conservation efforts. Future research integrating advanced reprogramming tools may pave the way for genetic rescue strategies in wisent and other endangered species.

Good Manufacturing Practice-grade fibronectin for hollow-fiber bioreactor cell manufacture: a mesenchymal stromal cell case study

BACKGROUND AIMS

The need for large-scale production of mesenchymal stromal cell (MSC)-based cellular therapeutics continues to grow around the globe. Manual cell expansion processes can be highly variable between operators, require significant hands-on time from skilled staff and, because of the large number of open manipulation steps required to produce cells in dose-relevant quantities, be prone to greater risk of contamination relative to automated processes. All of these can increase overall production costs and risks to the patient. In order to meet the needs of this growing industry, viable options for large-scale automation coupled with consistent and compliant ancillary materials needed to drive cell expansion are needed.

METHODS

In the work described herein, the automated and functionally closed hollow-fiber bioreactor system Quantum Flex (Terumo Blood and Cell Technologies, Inc., Lakewood, CO, USA) was used in conjunction with Good Manufacturing Practice (GMP)-compliant, virus-inactivated human fibronectin (FN) from Akron Bio (Boca Raton, FL, USA) to expand MSCs to clinically relevant numbers. In order to assess the performance of Akron Bio's GMP-grade FN, use of this product in the production of MSCs was referenced against use of a research-use-only (RUO)-grade FN product used extensively for MSC expansion in Quantum. Because many MSC-based processes require passaging of cells to attain the appropriate number of cells needed, a two-passage process was employed comparing the transfer of MSCs expanded on RUO FN to RUO FN, GMP FN to GMP FN and RUO FN to GMP FN to assess the impacts of transitioning from one grade of FN to another, as a product might be required to do as it moves from pre-clinical to clinical stages and beyond.

RESULTS

No statistically significant differences were noted when MSCs were transferred from RUO FN to RUO FN, GMP FN to GMP FN or RUO FN to GMP FN in terms of harvest yield, population doubling time, seeding efficiency estimates or fold expansion. All MSCs harvested from all groups met International Society for Cell & Gene Therapy standards for MSCs in terms of protein marker expression measured by flow cytometry, adherence to plastic, downstream cell morphology and trilineage differentiation.

CONCLUSIONS

The combination of Quantum Flex as an expansion platform and Akron Bio's GMP FN is seen as an attractive option for larger-scale manufacture of GMP-grade MSC products.

Design of dual peptide-conjugated hydrogels for proliferation and differentiation of human pluripotent stem cells

Completely synthetic cell cultivation materials for human pluripotent stem cells (hPSCs) are important for the future clinical use of hPSC-derived cells. Currently, cell culture materials conjugated with extracellular matrix (ECM)-derived peptides are being prepared using only one specific integrin-targeting peptide. We designed dual peptide-conjugated hydrogels, for which each peptide was selected from different ECM sites: the laminin β4 chain and fibronectin or vitronectin, which can target α6β1 and α2β1 or αVβ5. hPSCs cultured on dual peptide-conjugated hydrogels, especially on hydrogels conjugated with peptides obtained from the laminin β4 chain and vitronectin with a low peptide concentration of 200 μg/mL, showed high proliferation ability over the long term and differentiated into cells originating from 3 germ layers in vivo as well as a specific lineage of cardiac cells. The design of grafting peptides was also important, for which a joint segment and positive amino acids were added into the designed peptide. Because of the designed peptides on the hydrogels, only 200 μg/mL peptide solution was sufficient for grafting on the hydrogels, and the hydrogels supported hPSC cultures long-term; in contrast, in previous studies, greater than 1000 μg/mL peptide solution was needed for the grafting of peptides on cell culture materials.

Laminin Alpha 2 Enhances the Protective Effect of Exosomes on Human iPSC-Derived Cardiomyocytes in an In Vitro Ischemia-Reoxygenation Model

Ischemic heart disease, a leading cause of death worldwide, manifests clinically as myocardial infarction. Contemporary therapies using mesenchymal stromal cells (MSCs) and their derivative (exosomes, EXOs) were developed to decrease the progression of cell damage during ischemic injury. Laminin alpha 2 (LAMA2) is an important extracellular matrix protein of the heart. Here, we generated MSC-derived exosomes cultivated under LAMA2 coating to enhance human-induced pluripotent stem cell (hiPSC)-cardiomyocyte recognition of LAMA2-EXOs, thus, increasing cell protection during ischemia reoxygenation. We mapped the mRNA content of LAMA2 and gelatin-EXOs and identified 798 genes that were differentially expressed, including genes associated with cardiac muscle development and extracellular matrix organization. Cells were treated with LAMA2-EXOs 2 h before a 4 h ischemia period (1% O2, 5% CO2, glucose-free media). LAMA2-EXOs had a two-fold protective effect compared to non-treatment on plasma membrane integrity and the apoptosis activation pathway; after a 1.5 h recovery period (20% O2, 5% CO2, cardiomyocyte-enriched media), cardiomyocytes treated with LAMA2-EXOs showed faster recovery than did the control group. Although EXOs had a protective effect on endothelial cells, there was no LAMA2-enhanced protection on these cells. This is the first report of LAMA2-EXOs used to treat cardiomyocytes that underwent ischemia-reoxygenation injury. Overall, we showed that membrane-specific EXOs may help improve cardiomyocyte survival in treating ischemic cardiovascular disease.