Mechanical stretch activates the JAK/STAT pathway in rat cardiomyocytes

Area of Science:

• Cardiovascular Biology
• Molecular Cardiology
• Cell Signaling

Background:

• Mechanical forces are critical regulators of cardiomyocyte function.
• The Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway plays a role in cellular responses to stimuli.
• Understanding signaling pathways activated by mechanical stress is crucial for cardiac health.

Purpose of the Study:

• To investigate if mechanical stretch activates the JAK/STAT pathway in cardiomyocytes.
• To elucidate the specific mechanisms and signaling molecules involved in this activation process.

Main Methods:

• Primary neonatal rat/murine cardiomyocytes were subjected to mechanical stretch (20%) on silicone dishes.
• Western blotting and gel mobility shift assays were used to assess protein phosphorylation and DNA binding.
• Pharmacological inhibitors and blocking antibodies were employed to dissect signaling pathways.

Main Results:

• Mechanical stretch rapidly induced phosphorylation of JAKs, STATs, and glycoprotein 130.
• STAT3 activation was confirmed via gel mobility shift assays.
• Angiotensin II, interleukin-6 family cytokines, intracellular calcium, and protein kinase C were implicated in the activation.
• Endothelin-1 and stretch-activated ion channels were found to be independent of this pathway.

Conclusions:

• Mechanical stretch activates the JAK/STAT signaling pathway in cardiomyocytes.
• This activation is a complex process involving autocrine/paracrine factors, intracellular calcium, and protein kinase C.
• The findings provide insights into the molecular mechanisms underlying cardiac mechanotransduction.