iPSCs are very similar to ESCs in morphology, gene and protein expression, epigenetic modification, cell proliferation, and differentiation and can differentiate into cardiomyocytes, nerve cells, liver cells, and islet cells. Importantly iPSCs can be reprogrammed from somatic cells, so there is no immune rejection. They have a wide range of applications, including personalized drug screening, gene correction, cell transplantation, and tissue engineering, making them essential in regenerative medicine research. At the same time, it avoids the ethical difficulties that ESCS faces in terms of access [18].
Although it has a decent chance of implementation, several questions still need to be addressed because transcription factors are required to use viruses as vectors during reprogramming; incorporating the virus-mediated genomic DNA gene is probable, leading to proto-oncogenes activation and tumor-forming induction[19]. Likewise, Nakagawa et al. 18059259 demonstrated that the efficacy of OSKM's reprogramming of FBs into HIPSCs was poor. Therefore, the key challenges encountered at present are improving reprogramming and reducing the usage of transcription factors. According to a previous report, we find that it can provide valuable knowledge for improving reprogramming schemes and improving reprogramming performance by disclosing the main events controlling reprogramming and the multifunctional regulatory network [20].
A total of 622 DEGs, including 344 up regulated and 278 down-regulated genes, were defined in this study from three datasets, GSE34309, GSE43996, GSE56805, utilizing online research methods for integrated bioinformatics and Geo2R. We established that these DEGs were predominantly localized in the following functional categories by GO functional annotations, including extracellular matrix, DNA replication, mitosis, cell cycle, protein binding, etc. Likewise, we discovered that these DEGs were mainly enriched by the cell cycle, DNA replication, extracellular matrix receptor interaction, cell division, p53 signaling pathway, etc., from the KEGG pathway enrichment study. The PPI network was being built using the String database. Then, essential modules were studied in the PPI network, and Bub1 was the most fundamental gene in the PPI network, focused mainly on the cell cycle. Five HUB genes, including CDK1, EGFR, FN1, BRCA1, and CCNB1, have been screened in particular.
A significant aspect of the spindle check-up method is benzene and imidazole budding disinhibiting homolog protein 1 (BUB1). The spindle inspection performs an essential function during mitosis. It aims to ensure that genetic material replicated by cells in the mitotic chromosome phase is safe and correct after being allocated to each child cell and to prevent the occurrence of aneuploidy daughter cells. Lowering the BUb1 breast cancer cell line has been shown to avoid xenograft in immunocompromised mice, primarily attributed to decreased tumor stem cell capacity and improved susceptibility to radiotherapy[21]. Therefore, in stem cell pluripotency preservation, Bub1 is active. Likewise, Li et al. [22] found that Bub1, OCT4, Nanog, TDGF1, and other dry genes were heavily expressed and responsible for cell self-renewal and pluripotent differentiation via the discovery of gene expression profiles in ESCs. Our results were concordant with the previous findings and provided insights into the molecular mechanism.
Fibronectin (FN), one of the main fibrillary proteins, has been involved in cell-multitrophic (cell-differentiating) and cellular proliferation and differentiation. Following FN1-KO extension, the number of human infrapatellar fat pad derived stem cells was increased, but this rise was negated by FN1 cells after implantation into ECM[23]. Likewise, recent findings have found that the glucocorticoid receptor enhances the proliferative mesenchymal progenitor cell's acquisition of fibroblast matrix-derived signals such as Fn1 through and Wnt-1 and JAK-STAT, concerning their activity in the extracellular environment by other cells, and thus indirectly regulates a subset of those cells responsible for promoting tissue extracellular matrix gene expression, especially the cells[24]. Therefore in this study, we might be supposed that Fn1 is one of the major factors that enhance the reprogramming factors of FBs into iPSCs
It’s well known that in cell cycle control, especially mitosis, cyclin-dependent kinase 1 (CDK1) plays a key role. Previous studies have shown that CDK1 down regulation contributes to G2 step aggregation of HIPSCs, dry gene down regulation (OCT4, KLF4, and LIN28), and pluripotent morphology failure. Various lineage markers, linked to the separation of trophoblastic ectoderm, and spreading to other lineages, such as ectoderm, mesoderm, and endoderm, are up regulated [25]. Wang et al. [26]further revealed that CDK1 would target PDK1 directly, thereby influencing PI3K/Akt's behavior and its ERK and GSK3β effectors. Also, by controlling IPSC maturation, the CCNB1-CDK1 complex may facilitate somatic reprogramming performance since cyclin B1 may induce higher LIN28A levels, indicating that this could be a new direction to increase reprogramming efficiency and also provide a new pluripotency regulation and acquisition kinase cascade mechanism. Therefore, we might suggest that the complex CCNB1-CDK1 plays a pivotal role in regulating the cell cycle in iPSCs during reprogramming.
Brill et al. [27]found out that the EGFR family is active in pluripotent stem cell self-renewal and that widespread apoptosis has been observed in undifferentiated pluripotent stem cells treated with 10 M EGFR inhibitors, in line with previous reports[28]. Indeed, EGFR trans-membrane, which connects the cellular signal transduction with the growth, differentiation, and survival by interacting with EGF and other growth factors (EGF) or other types of growth factors to bind with it, thereby allowing it to initiate signal transduction pathways. Thus, suppression of EGFR signaling is conducive to gene reprogramming. Therefore, large amounts of epigenetic modulation are observed to cover a broad spectrum of cardiac enhancers, the researchers noted, and how they are linked to the regulatory mechanisms involved in myocyte reprogramming [29]. Regardless we might hypothesize that knockdown of the gene EGFR during reprogramming of FBs into iPSCs could enhance the reprogramming rate.
Through studying the genomes of the 24 iPS lines, researchers found that they have the same types of derivative gene mutations (de novo) in both BRCA and non-BRCA tumor types. This evidence demonstrates that BRCA-1 fibroblast-derived iPS lines may be used to research mutation impact on gene stability and the resulting gene expression [30]. Furthermore, double knockdown experiments discovered that BRC1 works, and a DNA harm response were also shown to be needed for it. The combination of Mesenchymal to epithelial transformation is also occurring at decreased levels in BRCA-1 knockouts. Thoroughly comprehending the context-dependent expansion is a key to understanding the shape and structure of the colonies that are formed as critical in early reprogramming often establishes baseline characteristics of morphology [31]. Taken together, we suppose that inhibition of BRCA-1 could also enhance the reprogramming ratio of FBs into iPSCs.