3D Organoid Cultures to Serve as Model System for Kidney Disease Research

By combining an advanced genome editing technique with stem cell technology cell biologists have succeeded in establishing the growth in culture of functional three-dimensional kidney-like organoids and spheroids.

Kidney disease affects approximately 700 million people worldwide, with some 12 million patients having polycystic kidney disease and another two million having complete kidney failure. New model systems are required to advance research that could lead to better treatment options for kidney disease patients.

Investigators at Brigham and Women's Hospital (Boston, MA, USA) used the CRISPR genome editing technique to modify human-pluripotent-stem-cell-derived kidney cells (hPSC-KCs) for growth in three-dimensional cell cultures.

CRISPRs (clustered regularly interspaced short palindromic repeats) are segments of prokaryotic DNA containing short repetitions of base sequences. Each repetition is followed by short segments of "spacer DNA" from previous exposures to a bacterial virus or plasmid. CRISPRs are found in approximately 40% of sequenced bacteria genomes and 90% of sequenced archaea. Since 2013, the CRISPR technique has been used in research for gene editing (adding, disrupting, or changing the sequence of specific genes) and gene regulation. By delivering appropriate guide RNAs into a cell, the organism's genome can be cut at any desired location.

In a paper published in the October 23, 2015, online edition of the journal Nature Communications the investigators described the establishment of adherent, three-dimensional growth conditions for reconstitution of two distinct epithelial structures, epiblast spheroids and kidney organoids, which arose sequentially in a single continuous culture of hPSCs. Using small molecule treatments and genome-edited hPSCs, they demonstrated that these structures were capable of reconstituting tissue-specific epithelial transport, toxicity responses, and disease phenotypes.

In three-dimensional cultures, epiblast-stage hPSCs formed spheroids surrounding hollow, amniotic-like cavities. GSK3beta (glycogen synthase kinase 3 beta) inhibition differentiated the spheroids into segmented, nephron-like kidney organoids containing cell populations with characteristics of proximal tubules, podocytes, and endothelium.

"Mutation of a single gene results in changes kidney structures associated with human disease, thereby allowing better understanding of the disease and serving as models to develop therapeutic agents to treat these diseases," said senior author Dr. Joseph Bonventre, chief of the renal division at Brigham and Women's Hospital.

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