Spontaneous Efficient Differentiation of Human Pluripotent Stem Cells (hPSC) Upon Co-culture of hPSCs with Human Neonatal Foreskin Fibroblasts in 3D.

Pluripotent stem cells (PSCs) form well-formed embryoid bodies (EBs) in 3D culture. These EBs are formed in culture media lacking leukemia inhibitory factor (LIF) or basic fibroblast growth factor (bFGF) in mouse and human PSCs, respectively. EBs are excellent technical tools for understanding developmental biology and inducing controlled differentiation in succeeding experimental steps. Technically speaking, EBs are spontaneously differentiated PSCs in 3D and exhibit all three lineages in a time-point/sequential manner. For example, ectoderm will form first, followed by mesoderm and endoderm. We have attempted to co-culture human neonatal foreskin-derived fibroblast cells in our laboratory with the PSCs first in 2D conditions followed by the induction of EBs (PSC+fibroblasts co-cultured) in low attachment dishes. We also performed spontaneous differentiation of such EBs (co-cultured with fibroblasts). We checked the presence of markers of various lineages, namely, ectoderm, mesoderm, and endoderm in days 6, 10, and 12 day EBs. We have also compared the fibroblast co-cultured EBs, along with control EBs (derived from only PSCs). This co-culture system mimics the natural conditions of uterine implantation and the role of the endometrial fibroblasts in the induction of further embryonic development. The fibroblast co-cultured iPSC EBs had better roundness scores than the normal iPSC EBs and had a higher expression of lineage-specific markers.

Arachidonic acid regulates pluripotency by modulating cellular energetics via fatty acid synthesis and mitochondrial fission.

Arachidonic acid (AA) is an important omega-6 fatty acid that can be metabolised into an impressive spectrum of biologically active mediators participating in various cellular functions. Studies have shown that fatty acid synthesis is enhanced in embryonic stem cells (ESCs), and it is crucial for the cellular reprogramming of somatic cells into induced pluripotent stem cells (iPSCs). Fatty acid synthesis increases the cellular lipid contents and, in turn, promotes mitochondrial fission and cellular reprogramming. AA was found to induce acetyl-CoA carboxylase 1 (ACC1) expression, a major enzyme in fatty acid synthesis. In this study, we have investigated the regulation of pluripotency, fatty acid synthesis and mitochondrial activities of the human induced pluripotent stem cells (hiPSCs) and the human embryonal carcinoma (hEC) NTERA-2 cells upon treatment with varying concentrations of AA. Our results indicate that a lower concentration of AA can increase pluripotency, as evidenced by an increased expression of pluripotency markers, increased fatty acid synthesis as evidenced by lipid estimation and modulated mitochondrial fission, as evidenced by mitotracker staining for fissioned mitochondria. Moreover, higher concentrations of AA-induced the opposite effect, leading to pluripotent stem cell differentiation. Molecular docking simulations predicted the possible interactions between AA and its metabolites with fatty acid synthesis regulators ACC1 and CREB1 (Cyclic adenosine monophosphate Response Element Binding Protein 1) as a mechanism for AA regulating pluripotency.

Arachidonic acid modulates the cellular energetics of human pluripotent stem cells and protects the embryoid bodies from embryotoxicity effects in vitro.

Arachidonic acid (AA), an ω-6 polyunsaturated fatty acid involved in signalling pathways that drive cell fate decisions, has an enhancing role in the immunomodulatory effect on mesenchymal stem cells and the vasculogenesis of embryonic stem cells. 3D embryoid bodies (EBs) from pluripotent stem cells (PSCs) have been used as in vitro models for embryotoxicity for various compounds/drugs. Valproic acid (VA), a common anti-epileptic drug, is known to be embryotoxic and cause malformations in embryos. As early embryogenesis depends on AA, we investigated the embryo protective effects of AA against the embryotoxic drug VA in this study. The effects of AA on the proliferation and cell cycle parameters of PSCs were studied. In particular, the potential of AA to abrogate VA-induced embryotoxicity in vitro was evaluated using ROS detection and antioxidant assays. In response to AA, we observed modulation in cell proliferation of induced pluripotent stem cells (iPSCs) and pluripotent NTERA-2 embryonal carcinoma (EC) cells. The present study substantiates the cytoprotective effects of AA against VA. These results imply that AA plays a critical role in the proliferation and differentiation of iPSCs and EC cells and protects the EBs from cytotoxic damage, thereby ensuring normal embryogenesis. Thus, the bioactive lipid AA may be explored for supplementation to benefit pregnant women treated with long-term anti-epileptic drugs to prevent in-utero fetal growth malformations.

Pluripotent stem cells: Basic biology or else differentiations aimed at translational research and the role of flow cytometry.

Pluripotent stem cell research has revolutionized the modern era for the past 14 years with the advent of induced pluripotent stem cells. Before this time, scientists had access to human and mouse embryonic stem cells primarily for basic research and an attempt towards lineage-specific differentiations for cell therapy applications. Regarding pluripotent stem cells, expression of bonafide marker proteins such as Oct4, Nanog, Sox2, Klf4, c-Myc, and Lin28 have been considered giving a perfect readout for pluripotent stem cells and assessed using an analytical flow cytometer. In addition to the intracellular markers, surface markers such as stage-specific embryonic antigen-1 for mouse cells and SSEA-4 for human cells are needed to sort pure populations of stem cells for further downstream applications for cell therapy. The surface marker SSEA-4 is the most appropriate for obtaining pure populations of human pluripotent stem cells. When differentiated in a controlled manner using growth factors or small molecules, it is mandatory to assess the downregulation of pluripotency markers (Oct4, Nanog, Sox2, and Klf4) with subsequent up-regulation of stage-specific differentiation markers. Such assessments are done using flow cytometry. Pluripotent stem cells have a high teratoma-forming potential in vivo. Small amounts of undifferentiated PSCs might lead to dangerous teratomas upon transplantation if leftover in the pool of differentiated cells. Hence, flow cytometry is essential for sorting out PSC populations with teratoma-forming potential. The pure populations of differentiated progenitors need to be flow-sorted before differentiating them further for cell therapy applications. For example, Glycoprotein 2 is a specific cell-surface marker for pancreatic progenitors that enables one to sort the pancreatic progenitors differentiated from human PSCs. Taken together, analytical flow cytometry, and cell sorting provide indispensable tools in PSC research and cell therapy.

Significance of Oct-4 transcription factor as a pivotal therapeutic target for CD44+ /24- mammary tumor initiating cells: Aiming at the root of the recurrence.

Breast cancer (BC) remains one of the deadliest and frequently diagnosed metastatic cancers worldwide. Cancer stem cells (CSCs) are the cell population within the tumor niche, having an epithelial to mesenchymal (EMT) transition phenotype, high self-renewal, vigorous metastatic capacity, drug resistance, and tumor relapse. Identification of targets for induction of apoptosis is essential to provide novel therapeutic approaches in BC. Our earlier studies showed that Vitamin C induces apoptotic cell death by losing redox balance in TNBC CSCs. In this study, we have attempted to identify previously unrecognized CSC survival factors that can be used as druggable targets for bCSCs apoptosis regulators isolated from the TNBC line, MDA MB 468. After a thorough literature review, Oct-4 was identified as the most promising marker for its unique abundance in cancer and absence in normal cells and the contribution of Oct-4 to the sustenance of cancer cells. We then validated a very high expression of Oct-4 in the MDA MB 468 bCSCs population using flow-cytometry. The loss of Oct-4 was carried out using small interfering RNA (siRNA)-mediated knockdown in the bCSCs, followed by assessing for cellular apoptosis. Our results indicated that Oct-4 knockdown induced cell death, changes in cellular morphology, inhibited mammosphere formation, and positive for Annexin-V expression, thereby indicating the role of Oct-4 in bCSC survival. Moreover, our findings also suggest the direct interaction between Oct-4 and Vitamin C using in silico docking. This data, hence, contributes towards novel information about Oct-4 highlighting this molecule as a novel survival factor in bCSCs.

Cell therapy research for Diabetes: Pancreatic ß cell differentiation from pluripotent stem cells.

Human pluripotent stem cells (PSCs), both embryonic and induced pluripotent stem cells (iPSCs), have been differentiated into pancreatic ß isletsin vitrofor more than a decade. The idea is to get enough ß cells for cell transplantation for diabetics. Finding a standard cell therapy for diabetes is essential because of the logarithmic increase in the global population of people with diabetes and the insufficient availability of the human cadaveric pancreas. Moreover, with better insights into developmental biology, thein vitroß cell differentiation protocols have depended on thein vivoß cell organogenesis. Various protocols for pancreatic ß cell differentiation have been developed. Such protocols are based on the modulation of cell signalling pathways with growth factors, small molecules, RNAi approaches, directed differentiation using transcription factors, genome editing. Growth factor free differentiation protocols, epigenetic modulations, 3D differentiation approaches, and encapsulation strategies have also been reported for better glycemic control and endocrine modulations. Here, we have reviewed various aforementionedin vitroß cell differentiation protocols from human PSCs, their respective comparisons, challenges, past, present, and future. The literature has been reviewed primarily from PubMed from the year 2000 till date using the mentioned keywords.

Induced Pluripotent Stem Cell Derived Human Lung Organoids to Map and Treat the SARS-CoV2 Infections In Vitro.

COVID-19 is the current day pandemic that has claimed around 1,054,604 lives globally till date. Moreover, the number of deaths is going to increase over the next few months until the pandemic comes to an end, and a second wave has also been reported in few countries. Most interestingly, the death rate among certain populations from the same COVID-19 infection is highly variable. For instance, the European populations show a very high death rate, in contrast to the populations from Chinese ethnicities. Amongst all the closed cases with an outcome (total recovered + total died), the death rate in Italy is 13%, Iran is 6%, China is 5%, Brazil is 3%, The United States of America is 2%, India 2%, Israel is 1% as of October 08, 2020. However, the percentage was higher during the early phase of the pandemic. Moreover, the global death rate amongst all the patients with an outcome is 4%. Here we have reviewed virus-transmitted various respiratory tract infections and postulated a better understanding of SARS-CoV2 using lung stem cell organoids in vitro. Hence, here we propose the strategies of understanding first the infectivity/severity ratio of COVID-19 infections using various ethnicity originated induced pluripotent stem cell-derived lung stem cell organoids in vitro. The greater the infectivity to severity ratio, the better the disease outcome with the value of 1 being the worst disease outcome. This strategy will be useful for understanding the infectivity/severity ratio of virus induced respiratory tract infections for a possible betterment of community-based disease management. Also, such a strategy will be useful for screening the effect of various antiviral drugs/repurposed drugs for their efficacy in vitro.