Osmotic pressure-induced calcium response states

Osmotic pressure is essential for maintaining cellular homeostasis; however, the mechanisms by which cells sense and respond to acute osmotic stress remain incompletely understood. Here, we applied rapid osmotic pressure stimulation to cultured HEK293T cells and observed dynamic intracellular calcium responses. Acute hypotonic stimulation evoked calcium response patterns, whereas hypertonic and isotonic stress did not elicit similar effects. Mechanistically, these calcium signals originated from the endoplasmic reticulum via ryanodine receptor 2 and propagated to neighboring cells through Connexin 43-mediated gap junctions. These findings reveal a previously unrecognized role for calcium signaling in the acute cellular response to osmotic stress, providing new insights into the mechanisms of intercellular communication during osmotic adaptation.