Journal: bioRxiv
Article Title: Single-cell analysis of sterol-induced Ca 2+ signaling in human astrocytes by dynamic mode decomposition
doi: 10.64898/2026.02.09.704834
Figure Lengend Snippet: Simulation of calcium oscillations in astrocytes under varying SERCA pump activity. (A) Schematic representation of intracellular calcium handling components, illustrating selected proteins involved in astrocytic calcium signaling. The ordinary differential equation (ODE)–based framework incorporates cytosolic calcium influx pathways, inositol 1,4,5-trisphosphate receptor (IP 3 R)-mediated endoplasmic reticulum (ER) calcium release (Green), and SERCA-driven reuptake (Red), while other signaling modules are greyscale for simplicity. Components shown include G-protein-coupled receptors (GPCRs), phospholipase C (PLC), store-operated calcium entry (SOCE), purinergic P2X receptors (P2X), Piezo1 channels, transient receptor potential (TRP) channels, voltage-gated calcium channels (VGCCs), plasma membrane Ca 2+ -ATPase (PMCA), Na + /Ca 2+ exchanger (NCX), mitochondrial calcium uniporter (MCU), and secretory pathway Ca 2+ -ATPase (SPCA). (B) Simulated cytosolic Ca 2+ dynamics for three levels of SERCA activity ( v m 2 = 5, 10, and 15 µ M/s). Higher SERCA rates lead to more frequent and higher-amplitude oscillations. (C) Corresponding ER Ca 2+ dynamics show complementary depletion and refilling behavior across the same SERCA conditions. (D) Phase-plane trajectories (ER Ca 2+ vs. cytosolic Ca 2+ ) illustrate distinct dynamical regimes that emerge as a function of SERCA strength. (E) Distribution of 100 sampled v m 2 values drawn from three Gaussian distributions centered at 5 µ M/s (green), 10 µ M/s (orange), and 15 µ M/s (blue), used to generate the simulated variability in Ca 2+ dynamics. Together, the simulations demonstrate how altering SERCA activity modulates the frequency, amplitude, and qualitative form of astrocytic calcium oscillations.
Article Snippet: Normal human astrocytes immortalized with SV40 large T antigen (P10251-IM, Innoprot) were maintained in T25 culture flasks (Nunc EasYFlask, 156367, Thermo Fisher Scientific) at 37 °C in a humidified incubator with 5% CO 2 .
Techniques: Activity Assay, Clinical Proteomics, Membrane