Calcium mediates cell shape change in human peritoneal mesothelial cells

Area of Science:

• Physiology
• Cell Biology
• Immunology

Background:

• Mast cells release histamine, an inflammatory mediator.
• Histamine affects nearby cells like human peritoneal mesothelial cells (hPMC).
• Intracellular calcium ([Ca2+]i) signaling plays a role in cellular responses.

Purpose of the Study:

• Investigate histamine's effect on intracellular calcium ([Ca2+]i) in hPMC.
• Compare histamine's calcium response to ionophore A23187.
• Determine if [Ca2+]i mediates histamine-induced changes in hPMC shape.

Main Methods:

• Cultured hPMC loaded with Fura-2 to measure [Ca2+]i.
• Exposure to histamine and A23187.
• Immunocytochemistry for cortical actin (CA) and microtubules (MT); calcium chelation with BAPTA-AM.

Main Results:

• Histamine dose-dependently increased [Ca2+]i in hPMC.
• Histamine and A23187 caused cell elongation and altered cytoskeleton (CA, MT).
• Calcium chelation abolished histamine-induced cell elongation.

Conclusions:

• Increased [Ca2+]i is crucial for histamine-induced hPMC elongation and stress fiber formation.
• Histamine modulates hPMC shape via intracellular calcium signaling.
• Calcium signaling is vital for regulating the peritoneal membrane barrier function.