“Human-induced Pluripotent Cell (hiPSC) isolation and formation of organoids” 

Dr Mamta Mishra, M.Sc., M.Phil., Ph.D.,
Senior Research Scientist,
Jai Research Foundation, Gujarat, India

Induced pluripotent stem cells are artificial stem cells and do not exist naturally. Instead, they are generated or reprogrammed from somatic cells by ectopic expression of pluripotency factors or specific transcription factors (Sox2, Oct3/4, c-Myc and Klf4). In 2006, the iPSC technology was first introduced by Takahashi and Yamanaka. Various protocols are continuously evolving. To get the highest reprogramming efficiency, various methods are used to convert the somatic cells into iPSCs (Neeman-Egozi S et al., 2022). For different methods (retrovirus, lentivirus, Sendai virus, Adenovirus, Plasmid, Episomal plasmid, Pigg/Bac Transoposon, Minicircle DNA, Synthetic DNA) efficacy, preparation methods, delivery procedure, removal of exogenous factors vary. Integrative viruses and vectors provide the highest reprogramming efficiency; however, they are not very safe. Hence small molecules and microRNAs are used as non-integrative methods, although they have less reprogramming efficiency. The combination of lentiviruses and microRNAs (miRNAs) is used to get more efficient reprogramming. Particularly, episomal vectors provide both high-efficiency generation of iPSCs generation and safety. All the methods are used for isolating iPSCs, considering their potential application for basic research, disease modelling and drug screening (Moradi S et al., 2019).

   Reprogramming of human dermal fibroblast or keratinocytes to pluripotency provides a valuable experimental model for investigating the bases of cellular reprogramming and pluripotency as well as a practical and advantageous alternative for the generation of patient- and disease-specific pluripotent stem cells. The remarkable capacity of human induced pluripotent stem cells (hiPSCs) for self-renewal for an indefinite period and differentiation into almost any cell type of body with suitable conditions (Thomson J, et al.,1998 & Takahashi K, et al., 2007). Potentially, hiPSCs serve as the limitless source to differentiate any cells and hold the promise in a relied approach. Human iPSCs stand at the right place when animal models fail to predict therapeutic responses.

The world has moved so fast to find the best alternative model to replace the animal model. The advanced micro-physiological system (MPS) or organ-on Chips (OOC), simply called MPS technology, provides real strength at the right time. Scientists across the world have already made miniaturized organs (organoids) of almost all the parts of the human body (brain, liver, lung, kidney, intestine, pancreas, heart, skin, bone marrow, lymph nodes, retina, placenta and many more) on chips. Some more are on the way to come. OOC models allow for long-term monitoring and provide the capability of real-time with their microenvironments in understanding the basic biology, disease mechanism, drug screening & testing and personalised medicine. Almost all the organoids/ OOC models are derived from human induced pluripotent stem cells (hiPSCs). Scientists from academics, pharmaceutical industries and regulatory agencies must discuss the challenges of recent advances in OOCs and overcome them to move towards a greater goal for drug development. Human organ chips can be considered “Living Avatars” for personalized medicine and are ever closer to realization.