Name: IPSC Differentiation into Posterior Primitive Streak and Nephrogenic Intermediate Mesoderm
Uploaded: 2023-09-01T13:20:00
Description: Watch this Scientific Journal Video about IPSC Differentiation into Posterior Primitive Streak and Nephrogenic Intermediate Mesoderm at JoVE.com

ipsc differentiation into posterior primitive streak and nephrogenic intermediate mesoderm

Using Induced Pluripotent Stem Cell Suspension for Kidney Organoid Production

The kidney plays a critical role in maintaining physiological homeostasis, depending on its functional unit. Nephrons, which excrete waste products, can regulate the composition of body fluids. Chronic kidney disease (CKD), caused by hereditary mutations or other high-risk factors, will eventually progress to end-stage kidney disease (ESKD)1,2. ESKD is apparently due to the limited regeneration capacity of nephrons. Thus, renal replacement therapy is required. Directed differentiation of human iPSCs enables the in vitro generation of patient-specific 3D kidney organoids, which can be used to study kidney development, model patient-specific diseases, and perform nephrotoxic drug screening3,4.
During embryonic development, kidneys originate from the intermediate mesoderm (IM), which differentiates from the primitive streak (PS). The classical WNT signaling pathway may induce additional differentiation of IM with the coordinated participation of FGF (FGF9, FGF20) and BMP (Bmp7 signaling through JNK)5,6,7. They produce two important cell populations of nephric progenitor cells (NPC): the ureteral bud (UB), and the metanephric mesenchyme (MM), forming the collecting ducts and the nephron, respectively8,9. Each nephron consists of glomerular and tubular segments, such as the proximal and distal tubules, and the loop of Henle10,11. According to the theory mentioned above, currently published protocols mimic the signal cascades and growth factor stimulation to induce kidney organoids5,12.
Over the past several years, many protocols have been developed to differentiate human iPSCs into kidney organoids5,6,7,12. Takasato et al.7 optimized the duration of CHIR (WNT agonist) treatment before replacement by FGF9. According to their protocol, CHIR exposure for 4 days, followed by FGF9 for 3 days, is the most effective way to induce IM from iPSCs. Transwell filters were utilized as the culture format in their procedure; however, this method is difficult for beginners. Therefore, Kumar et al.13 tried to change the culture format and chose to suspend the culture. They dissociated the adherent cells on Day 7 for seeding in low adherent plates to help them assemble into embryoid bodies (EBs) that contain nephron-like structures. However, the batch effect of these methods was apparent, especially in different iPSCs. Additionally, different literature reported that the concentration of CHIR varied from 7 &#181;M to 12 &#181;M5,13,14.
We speculated that the concentration of cell density and the CHIR might affect the generation of organoids in different iPSCs, and this has been verified numerous times in our experiments. The present protocol has slightly modified the study method of Kumar et al.13 and provided users with a step-by-step procedure. The schedule and schematic of the approach are shown in Figure 1.

Author Spotlight: Optimizing iPSC Differentiation for Efficient Production to Generate Kidney Organoids 

Generating Kidney Organoids in Suspension from Induced Pluripotent Stem Cells

Our research presents a comprehensive and efficient method for producing kidney organoids from induced pluripotent stem cells, using suspension cultural conditions. We emphasize the importance of initial cell density and WNT agonist concentration during the inducing phase, which will educate new organoid researchers. Currently, it is difficult to obtain a single high-density cell line for iPSCs.The batch impact was noticeable, particularly in various iPSC lines. Each batch's kidney organoids, may have a varied form and size. Several attempts are necessary to get the best initial cell density and concentration of CHIR for one iPSC line.We have established that the initial differentiation of the intermediary method is important for successful kidney organoid formation. Our protocol describes in detail, how to choose the optimal cell densities and CHIR concentrations during the process because different iPSC lines showed variances in cell proliferation and differentiation ability. Researchers can quickly generate the specific kidney organoids from their iPSCs.According to our protocol, by adjusting the cell density and the concentration of CHIR, it's undoubtedly beneficial for all our researchers to focus on their kidney disease. Our lab future research has to optimize the method of the protocol in disease models, regenerate new medicine and the drug screening. In recent five years, our lab will focus on the epigenetics and the cell topic drug development of various hereditary kidney disease, based on patient development, iPSC and the kidney organized disease models.

Watch this Scientific Journal Video about IPSC Differentiation into Posterior Primitive Streak and Nephrogenic Intermediate Mesoderm at JoVE.com

IPSC Differentiation into Posterior Primitive Streak and Nephrogenic Intermediate Mesoderm  

iPSC Differentiation into Posterior Primitive Streak and Nephrogenic Intermediate Mesoderm

Begin by washing the induced pluripotent stem cells or iPSCs on the membrane matrix coated 6-well plate with two milliliters DPBS. Aspirate the DPBS using a pipette. Next, add one milliliter of the commercially available cell detachment solution to detach the iPSCs.Then place the cell into an incubator at 37 degrees for five minutes. Now pipette one milliliter of mTeSR onto the iPSCs, ensuring that the cells have separated from the plastic surface. Centrifuge these cells at 400g for three minutes at room temperature.Resuspend the cell pellet, then count the cell numbers using a hemocytometer. Next seed a range of cell densities on a 6-well plate that has been coated with a membrane matrix. Culture these with mTeSR supplemented with 10 micromolar Rho-kinase inhibitor.Culture the plates overnight in a carbon dioxide incubator set at 37 degrees Celsius. The next day aspirate the mTeSR and wash the cells with two milliliters of DPBS. Next, add two milliliters of stage 1 medium to the cells.Then place the cells in a 37 degrees Celsius incubator for four days. On day four, remove the stage 1 medium and wash the cells with two milliliters of DPBS. Then add two milliliters of stage 2 medium to the cells before incubating the cells as before.From day zero to day four, iPSCs rapidly expanded and took on rhomboid or triangular shapes. The confluence reached 90 to 100%and accumulated evenly until day seven. Upon suspension culture, the aggregates spontaneously form nephron structures after dissociating on day seven.

Research

JoVE Journal

Developmental Biology

Kidney organoids can be generated from induced pluripotent stem cells (iPSCs) through various approaches. These organoids hold great promise for disease ...