A high-throughput assay for the measurement of Ca²⁺ oscillations and insulin release from uniformly sized <i>mouse β-cell (MIN6</i>) spheroids

Diabetes mellitus poses a rising global health concern, highlighting the need for improved anti-diabetic treatments that enhance insulin secretion from pancreatic β-cells. Traditional screening techniques employ 2D β-cell cultures, which fail to replicate the 3D structure and cell-to-cell interactions found in pancreatic islets of Langerhans.

Current 3D culture models suffer from high costs, technical complexity, and limited compatibility with high-throughput screening setups. To address this, a method was devised to create 19 β-cell spheroids of uniform size in each well of a 96-well plate, utilizing PEG-based hydrogels and mouse insulinoma 6 (MIN6) cells. With this technique, simultaneous, real-time monitoring of Ca2+ signals in up to 1824 individual spheroids upon glucose and compound exposure became possible.

The findings revealed that heightened glucose triggers concentration-dependent Ca2+ oscillations in each spheroid, with these oscillations being responsive to ATP-sensitive K+ channel modulators and correlated with insulin release frequency. Moreover, the neurosteroid pregnenolone sulfate, a TRPM3 channel agonist, elevated the frequency of glucose-stimulated Ca2+ oscillations and boosted insulin release, while the TRPM3 antagonist isosakuranetin suppressed these effects.

This study successfully introduces a cost-efficient, scalable 3D β-cell platform for high-throughput screening of insulin release-modulating compounds, offering promising prospects for drug discovery and tailored therapies for diabetes management.