Improving Lentiviral Transduction of Human Adipose-Derived Mesenchymal Stem Cells

A human omentum-specific mesothelial-like stromal population inhibits adipogenesis through IGFBP2 secretion

Adipose tissue plasticity is orchestrated by molecularly and functionally diverse cells within the stromal vascular fraction (SVF). Although several mouse and human adipose SVF cellular subpopulations have by now been identified, we still lack an understanding of the cellular and functional variability of adipose stem and progenitor cell (ASPC) populations across human fat depots. To address this, we performed single-cell and bulk RNA sequencing (RNA-seq) analyses of >30 SVF/Lin- samples across four human adipose depots, revealing two ubiquitous human ASPC (hASPC) subpopulations with distinct proliferative and adipogenic properties but also depot- and BMI-dependent proportions. Furthermore, we identified an omental-specific, high IGFBP2-expressing stromal population that transitions between mesothelial and mesenchymal cell states and inhibits hASPC adipogenesis through IGFBP2 secretion. Our analyses highlight the molecular and cellular uniqueness of different adipose niches, while our discovery of an anti-adipogenic IGFBP2+ omental-specific population provides a new rationale for the biomedically relevant, limited adipogenic capacity of omental hASPCs.

Nanotechnology and bioengineering approaches to improve the potency of mesenchymal stem cell as an off-the-shelf versatile tumor delivery vehicle

Targeting actionable mutations in oncogene-driven cancers and the evolution of immuno-oncology are the two prominent revolutions that have influenced cancer treatment paradigms and caused the emergence of precision oncology. However, intertumoral and intratumoral heterogeneity are the main challenges in both fields of precision cancer treatment. In other words, finding a universal marker or pathway in patients suffering from a particular type of cancer is challenging. Therefore, targeting a single hallmark or pathway with a single targeted therapeutic will not be efficient for fighting against tumor heterogeneity. Mesenchymal stem cells (MSCs) possess favorable characteristics for cellular therapy, including their hypoimmune nature, inherent tumor-tropism property, straightforward isolation, and multilineage differentiation potential. MSCs can be loaded with various chemotherapeutics and oncolytic viruses. The combination of these intrinsic features with the possibility of genetic manipulation makes them a versatile tumor delivery vehicle that can be used for in vivo selective tumor delivery of various chemotherapeutic and biological therapeutics. MSCs can be used as biofactory for the local production of chemical or biological anticancer agents at the tumor site. MSC-mediated immunotherapy could facilitate the sustained release of immunotherapeutic agents specifically at the tumor site, and allow for the achievement of therapeutic concentrations without the need for repetitive systemic administration of high therapeutic doses. Despite the enthusiasm evoked by preclinical studies that used MSC in various cancer therapy approaches, the translation of MSCs into clinical applications has faced serious challenges. This manuscript, with a critical viewpoint, reviewed the preclinical and clinical studies that have evaluated MSCs as a selective tumor delivery tool in various cancer therapy approaches, including gene therapy, immunotherapy, and chemotherapy. Then, the novel nanotechnology and bioengineering approaches that can improve the potency of MSC for tumor targeting and overcoming challenges related to their low localization at the tumor sites are discussed.

Identification of a small molecule for enhancing lentiviral transduction of T cells

Genetic modification of cells using viral vectors has shown huge therapeutic benefit in multiple diseases. However, inefficient transduction contributes to the high cost of these therapies. Several transduction-enhancing small molecules have previously been identified; however, some may be toxic to the cells or patient, otherwise alter cellular characteristics, or further increase manufacturing complexity. In this study, we aimed to identify molecules capable of enhancing lentiviral transduction of T cells from available small-molecule libraries. We conducted a high-throughput flow-cytometry-based screen of 27,892 compounds, which subsequently was narrowed down to six transduction-enhancing small molecules for further testing with two therapeutic lentiviral vectors used to manufacture GSK's clinical T cell therapy products. We demonstrate enhanced transduction without a negative impact on other product attributes. Furthermore, we present results of transcriptomic analysis, suggesting alteration of ribosome biogenesis, resulting in reduced interferon response, as a potential mechanism of action for the transduction-enhancing activity of the lead compound. Finally, we demonstrate the ability of the lead transduction enhancer to produce a comparable T cell product using a 3-fold reduction in vector volume in our clinical manufacturing process, resulting in a predicted 15% reduction in the overall cost of goods.

3D Microcapsules for Human Bone Marrow Derived Mesenchymal Stem Cell Biomanufacturing in a Vertical-Wheel Bioreactor

Microencapsulation of human mesenchymal stromal cells (MSCs) via electrospraying has been well documented in tissue engineering and regenerative medicine. Herein, we report the use of microencapsulation, via electrospraying, for MSC expansion using a commercially available hydrogel that is durable, optimized to MSC culture, and enzymatically degradable for cell recovery. Critical parameters of the electrospraying encapsulation process such as seeding density, correlation of microcapsule output with hydrogel volume, and applied voltage were characterized to consistently fabricate cell-laden microcapsules of uniform size. Upon encapsulation, we then verified ~ 10x expansion of encapsulated MSCs within a vertical-wheel bioreactor and the preservation of critical quality attributes such as immunophenotype and multipotency after expansion and cell recovery. Finally, we highlight the genetic manipulation of encapsulated MSCs as an example of incorporating bioactive agents in the capsule material to create new compositions of MSCs with altered phenotypes.