DMSO Priming Boosts Kidney Organoid Formation from Stem Cells

Kidney organoids derived from human induced pluripotent stem cells (hiPSCs) hold enormous promise for modeling renal disease, screening nephrotoxic drugs, and ultimately supporting regenerative medicine. However, existing differentiation protocols remain inefficient and inconsistent across cell lines, motivating the search for simple interventions that improve starting cell quality before differentiation begins.

This study from Maastricht University's MERLN Institute investigated whether a brief, low-dose dimethyl sulfoxide (DMSO) treatment could 'condition' hiPSCs to differentiate more efficiently into kidney organoids. Three validated hiPSC lines (LUMC, H101, H107) were treated with 0%, 1%, or 2% DMSO for 24 hours, then subjected to the well-established Morizane et al. 2017 stepwise 2D monolayer protocol progressing through primitive streak, intermediate mesoderm, nephron progenitor, and finally kidney organoid stages over 21 days.

DMSO treatment produced several notable changes in hiPSCs prior to differentiation. At 1–2% concentrations, DMSO downregulated key pluripotency transcription factors (OCT4, SOX2) and altered surface pluripotency markers (TRA-1-60, TRA-1-81, SSEA3, SSEA4) as measured by flow cytometry. Epigenetic remodeling was detected, consistent with DMSO's known ability to affect chromatin accessibility. Colony morphology became noticeably altered, with cells displaying a more condensed and uniform appearance. Cell cycle analysis confirmed G1-phase synchronization, consistent with earlier reports that DMSO inhibits retinoblastoma phosphorylation via PI3K pathway modulation, effectively pausing cells in a state more receptive to differentiation cues.

Downstream differentiation outcomes were substantially improved. By day 9 of the protocol, DMSO-treated hiPSCs showed significantly enhanced expression of SIX2, the defining marker of metanephric mesenchyme nephron progenitor cells. At the end of the 21-day protocol, DMSO-conditioned cultures yielded more kidney organoids with clearly defined tubular structures—including proximal tubules, distal tubules, glomerular-like structures, and collecting duct markers (PODXL, LRP2, GATA3)—compared to untreated controls. The effect was observed across multiple independent hiPSC lines, suggesting the benefit is not line-specific.

The authors propose that DMSO's impact on the PI3K signaling pathway, cytoskeletal dynamics, cell adhesion, and epigenetic state collectively prime hiPSCs toward a transitional pluripotent state that is more responsive to the Wnt (CHIR99021), Activin A, and FGF9 signaling used in the Morizane protocol. The low cost, simplicity, and broad applicability of a 24-hour DMSO pre-treatment step make this a readily adoptable modification. Limitations include the need for further mechanistic dissection of DMSO's epigenetic targets, lack of single-cell resolution data characterizing organoid composition, and open questions about whether off-target cell populations at later culture timepoints are also reduced.