Nutritional requirements of human induced pluripotent stem cells

Oxytetracycline and its Non-Antibiotic Derivative DOT Protect Midbrain Dopamine Neurons from Iron-Driven Oxidative Damage

This study aimed to investigate the neuroprotective potential of the tetracycline (TC) antibiotic oxytetracycline (OT) and its non-antibiotic derivative 4-dedimethylamino 12a-deoxy-oxytetracycline (DOT), in experimental conditions that mimic the gradual loss of dopamine (DA) neurons in Parkinson's disease (PD). Specifically, we established a model system of mouse midbrain cultures where DA neurons progressively die when exposed to an iron-containing medium. We found that OT (EC50 = 0.25µM) and DOT (EC50 = 0.34µM) efficiently protected DA neurons from degeneration, with these effects observable until advanced stages of neurodegeneration. The reference antibiotic TC doxycycline (DOX) also exhibited protective effects in this context. Importantly, DA neurons rescued by OT, DOT, and DOX retained their capacity to accumulate and release DA, indicating full functional integrity. Additionally, molecules with iron-chelating properties (apotransferrin, desferoxamine), as well as inhibitors of lipid peroxidation and ferroptosis (Trolox, Liproxstatin-1), could replicate the rescue of DA neurons provided by OT, DOT, and DOX. Live-cell imaging studies showed that test TCs and other neuroprotective molecules prevented the emission of intracellular reactive oxygen species and the associated disruption of the mitochondrial membrane potential. However, neither OT, DOT, nor DOX could protect DA neurons from selective mitochondrial poisoning by 1-methyl-4-phenylpyridinium. This suggests that test TCs may be protective against iron-mediated damage through a mechanism not directly involving mitochondria. Overall, we demonstrate that OT and DOT possess promising properties that could be useful for combating PD neurodegeneration. However, the absence of antimicrobial activity makes DOT a better candidate drug compared to its parent compound OT.

Examining patient-specific responses to PARP inhibitors in a novel, human induced pluripotent stem cell-based model of breast cancer

Preclinical models of breast cancer that better predict patient-specific drug responses are critical for expanding the clinical utility of targeted therapies, including for inhibitors of poly(ADP-ribose) polymerase (PARP). Reprogramming primary cancer cells into human induced pluripotent stem cells (hiPSCs) recently emerged as a powerful tool to model drug response phenotypes, but its use to date has been limited to hematopoietic malignancies. We designed an optimized reprogramming methodology to generate breast cancer-derived hiPSCs (BC-hiPSCs) from nine patients representing all major subtypes of breast cancer. BC-hiPSCs retain patient-specific oncogenic variants, including variants unique to individual tumor subclones. Additionally, we developed a protocol to differentiate BC-hiPSCs into mammary epithelial cells and mammary-like organoids for in vitro disease modeling, including drug response phenotyping. Using these tools, we demonstrated that BC-hiPSCs can be used to screen for differential sensitivity to PARP inhibitors and mechanistically investigated the causal genetic variant driving drug sensitivity in one patient.

Exploring cost reduction strategies for serum free media development

Cultivated meat production offers solutions in addressing global food security and sustainability challenges. However, serum-free media (SFM) used in cultivating the cells are expensive, contributing to at least 50% of variable operating costs. This review explores technologies for cost-effective SFM, focusing on reducing cost from using growth factors and recombinant proteins, using affordable raw materials for basal media, and implementing cost-saving measures like media recycling and reducing waste build-up.

Human induced pluripotent stem cell-derived cardiomyocytes to study inflammation-induced aberrant calcium transient

Heart failure with preserved ejection fraction (HFpEF) is commonly found in persons living with HIV (PLWH) even when antiretroviral therapy suppresses HIV viremia. However, studying this condition has been challenging because an appropriate animal model is not available. In this article, we studied calcium transient in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in culture to simulate the cardiomyocyte relaxation defect noted in PLWH and HFpEF and assess whether various drugs have an effect. We show that treatment of hiPSC-CMs with inflammatory cytokines (such as interferon-γ or TNF-α) impairs their Ca2+ uptake into sarcoplasmic reticulum and that SGLT2 inhibitors, clinically proven as effective for HFpEF, reverse this effect. Additionally, treatment with mitochondrial antioxidants (like mito-Tempo) and certain antiretrovirals resulted in the reversal of the effects of these cytokines on calcium transient. Finally, incubation of hiPSC-CMs with serum from HIV patients with and without diastolic dysfunction did not alter their Ca2+-decay time, indicating that the exposure to the serum of these patients is not sufficient to induce the decrease in Ca2+ uptake in vitro. Together, our results indicate that hiPSC-CMs can be used as a model to study molecular mechanisms of inflammation-mediated abnormal cardiomyocyte relaxation and screen for potential new interventions.

Independent compartmentalization of functional, metabolic, and transcriptional maturation of hiPSC-derived cardiomyocytes

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) recapitulate numerous disease and drug response phenotypes, but cell immaturity may limit their accuracy and fidelity as a model system. Cell culture medium modification is a common method for enhancing maturation, yet prior studies have used complex media with little understanding of individual component contribution, which may compromise long-term hiPSC-CM viability. Here, we developed high-throughput methods to measure hiPSC-CM maturation, determined factors that enhanced viability, and then systematically assessed the contribution of individual maturation medium components. We developed a medium that is compatible with extended culture. We discovered that hiPSC-CM maturation can be sub-specified into electrophysiological/EC coupling, metabolism, and gene expression and that induction of these attributes is largely independent. In this work, we establish a defined baseline for future studies of cardiomyocyte maturation. Furthermore, we provide a selection of medium formulae, optimized for distinct applications and priorities, that promote measurable attributes of maturation.

Combination Treatment with Liposomal Doxorubicin and Inductive Moderate Hyperthermia for Sarcoma Saos-2 Cells

Despite efforts in osteosarcoma (OS) research, the role of inductive moderate hyperthermia (IMH) in delivering and enhancing the antitumor effect of liposomal doxorubicin formulations (LDOX) remains unresolved. This study investigated the effect of a combination treatment with LDOX and IMH on Saos-2 human OS cells. We compared cell viability using a trypan blue assay, apoptosis and reactive oxygen species (ROS) measured by flow cytometry and pro-apoptotic Bax protein expression examined by immunocytochemistry in response to IMH (42 MHz frequency, 15 W power for 30 min), LDOX (0.4 μg/mL), and LDOX plus IMH. The lower IC50 value of LDOX at 72 h indicated increased accumulation of the drug in the OS cells. LDOX plus IMH resulted in a 61% lower cell viability compared to no treatment. Moreover, IMH potentiated the LDOX action on the Saos-2 cells by promoting ROS production at temperatures of <42 °C. There was a 12% increase in cell populations undergoing early apoptosis with a less heterogeneous distribution of Bax after combination treatment compared to those treated with LDOX (p < 0.05). Therefore, we determined that IMH could enhance LDOX delivery and its antitumor effect via altered membrane permeabilization, ROS generation, and a lower level of visualized Bax heterogeneity in the Saos-2 cells, suggesting the potential translation of these findings into in vivo studies.