Hematopoietic Differentiation of Human Pluripotent Stem Cells: HOX and GATA Transcription Factors as Master Regulators.

Numerous human disorders of the blood system would directly or indirectly benefit from therapeutic approaches that reconstitute the hematopoietic system. Hematopoietic stem cells (HSCs), either from matched donors or ex vivo manipulated autologous tissues, are the most used cellular source of cell therapy for a wide range of disorders. Due to the scarcity of matched donors and the difficulty of ex vivo expansion of HSCs, there is a growing interest in harnessing the potential of pluripotent stem cells (PSCs) as a de novo source of HSCs. PSCs make an ideal source of cells for regenerative medicine in general and for treating blood disorders in particular because they could expand indefinitely in culture and differentiate to any cell type in the body. However, advancement in deriving functional HSCs from PSCs has been slow. This is partly due to an incomplete understanding of the molecular mechanisms underlying normal hematopoiesis. In this review, we discuss the latest efforts to generate human PSC (hPSC)-derived HSCs capable of long-term engraftment. We review the regulation of the key transcription factors (TFs) in hematopoiesis and hematopoietic differentiation, the Homeobox (HOX) and GATA genes, and the interplay between them and microRNAs. We also propose that precise control of these master regulators during the course of hematopoietic differentiation is key to achieving functional hPSC-derived HSCs.

Public awareness and understanding of stem cell treatments available in Saudi Arabia and their trust in hospitals and research centers involved in stem cell research-a cross sectional study.

Introduction: Although stem cell research and therapeutic applications hold great promise for medical advancements, and have rapidly progressed globally, there remains a lack of genuine public awareness of the status of this subject in Saudi Arabia. Successful integration of stem cell therapy into healthcare relies on public awareness, understanding, and trust. Therefore, we aimed in this cross-sectional study to assess the public's knowledge, awareness, trust, support, participation, and confidence in stem cell treatments and centers involved in it. Materials and methods: A voluntary questionnaire of 20 questions was distributed randomly via social media outlets. Results: Three thousand five hundred eighty four individuals participated in the survey, with approximately half of them falling within the age range of 35-50 years (46.71%). Majority of the participants, 90.71%, would like to know more about stem cell therapy and more than half of the participants (56.94%) were unfamiliar with the idea, and a comparable proportion (50.41%) expressed concerns about the safety of stem cell therapy. A lower level of awareness, indicated by a score of 5, was evenly distributed across all age groups and genders. However, regardless of gender, older participants-especially those 50 years of age or older-tended to report higher levels of confidence, trust, and support than participants in other age groups. Moreover, trust, support, participation, and confidence score for those attained high school or less was statistically significantly lower than those attained master's or PhD degree. Of the participants, 33.57% had either received stem cell therapy themselves or known someone who had; about 24.07% of them reported that it was a cosmetic type of treatment. Conclusion: The study emphasizes the persistent need for awareness and educational initiatives to minimize the lack of public awareness and understanding of approved stem cell treatments in Saudi Arabia. It advocates for increased education, transparency, and communication to bridge knowledge gaps and enhance public trust to ensure the understanding of successful treatment.

An Infodemic of Misinformation on Stem Cell Therapy Among the Population of Saudi Arabia: A Cross-Sectional Study.

In recent years, the industry of unproven stem cell-based therapies has been on the rise around the globe, putting patients at great risk of potential harm. In this cross-sectional study, we aimed to assess the level of knowledge and awareness of the general public, including patients and/or their relatives, in Saudi Arabia on stem cell therapy and to assess the degree of willingness to try stem cell-based treatment options, should it be offered to them. Methods: A voluntary questionnaire of 16 questions was distributed randomly through social media outlets. Results: In the survey of this study, 2,030 individuals participated. A total of 1,292 (63.6%) stated that they would accept stem cell therapy or would recommend it to their friends and relatives. Alarmingly, 72.1% of participants were unaware that using unapproved stem cell-based treatments may lead to serious health complications including cancer. More than 20% believed that stem cell therapy is already approved for organ/tissue regeneration. Worryingly, 60.6% of the physicians and 56.4% of the medical students stated that they would recommend stem cell treatment for their patients. Conclusions: There is a concerning spread of misinformation among the Saudi population, including physicians, regarding stem cell therapy. This calls for a targeted effort to raise awareness about the current status of stem cell treatment in the general public and among health care practitioners.

Effects of maternal obesity on Wharton's Jelly mesenchymal stromal cells.

We investigated whether maternal metabolic environment affects mesenchymal stromal/stem cells (MSCs) from umbilical cord's Wharton's Jelly (WJ) on a molecular level, and potentially render them unsuitable for clinical use in multiple recipients. In this pilot study on umbilical cords post partum from healthy non-obese (BMI = 19-25; n = 7) and obese (BMI ≥ 30; n = 7) donors undergoing elective Cesarean section, we found that WJ MSC from obese donors showed slower population doubling and a stronger immunosuppressive activity. Genome-wide DNA methylation of triple positive (CD73+CD90+CD105+) WJ MSCs found 67 genes with at least one CpG site where the methylation difference was ≥0.2 in four or more obese donors. Only one gene, PNPLA7, demonstrated significant difference on methylome, transcriptome and protein level. Although the number of analysed donors is limited, our data suggest that the altered metabolic environment related to excessive body weight might bear consequences on the WJ MSCs.

Induced Pluripotent Stem Cell Differentiation and Three-Dimensional Tissue Formation Attenuate Clonal Epigenetic Differences in Trichohyalin.

The epigenetic background of pluripotent stem cells can influence transcriptional and functional behavior. Most of these data have been obtained in standard monolayer cell culture systems. In this study, we used exome sequencing, array comparative genomic hybridization (CGH), miRNA array, DNA methylation array, three-dimensional (3D) tissue engineering, and immunostaining to conduct a comparative analysis of two induced pluripotent stem cell (iPSC) lines used in engineering of 3D human epidermal equivalent (HEE), which more closely approximates epidermis. Exome sequencing and array CGH suggested that their genome was stable following 3 months of feeder-free culture. While the miRNAome was also not affected, ≈7% of CpG sites were differently methylated between the two lines. Analysis of the epidermal differentiation complex, a region on chromosome 1 that contains multiple genes involved in skin barrier maturation (including trichohyalin, TCHH), found that in one of the iPSC clones (iKCL004), TCHH retained a DNA methylation signature characteristic of the original somatic cells, whereas in other iPSC line (iKCL011), the TCHH methylation signature matched that of the human embryonic stem cell line KCL034. The difference between the two iPSC clones in TCHH methylation did not have an obvious effect on its expression in 3D HEE, suggesting that differentiation and tissue formation may mitigate variations in the iPSC methylome.

Isolation and expansion of mesenchymal stromal/stem cells from umbilical cord under chemically defined conditions.

From a perspective of manufacturer, procurement of bone marrow aspirates for isolation of mesenchymal stromal/stem cells (MSC) is challenging. The MSC isolated from adult donors have lower proliferation capacity than the cells isolated form young donors of pediatric age. To obtain more MSC from young healthy donors for allogeneic therapy on multiple patients, umbilical cord (UC) seems to be the best alternative. Here, we describe an easy, cost-effective and reproducible protocol of isolation of the MSC from Wharton's Jelly (WJ) in UC.

Wharton's jelly mesenchymal stromal/stem cells derived under chemically defined animal product-free low oxygen conditions are rich in MSCA-1(+) subpopulation.

AIM: Umbilical cord contains, within Wharton's jelly (WJ), multipotent mesenchymal stromal/stem cells (MSCs) of fetal origin that can be isolated and expanded in vitro with a minimal manipulation and very high efficiency. Our aim was to develop a highly reproducible protocol that has the unique potential to be scaled up and adapted to cGMP requirements for the use in cellular therapy. RESULTS: We found that derivation of WJ MSCs under defined conditions in low oxygen resulted in several folds higher populations of MSCA-1(+) cells (6.0-19.2%) when compared with WJ MSCs derived in the presence of serum (0.1-2.8%) or clinical-grade bone marrow (BM) MSCs cultured under atmospheric O2 (20%). We demonstrate that WJ MSCs derived following our protocol display antiproliferative activity similar to clinical-grade BM MSCs. We also show that these WJ MSCs can be differentiated into adipo-, chondro- and osteo-genic lineages. CONCLUSION: Easy accessibility, abundance and genetic 'naivety' make WJ MSCs logistically a more attractive source for clinical applications than BM MSCs.