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Updated: Jul 19, 2026
Primary Culture of Adult Rat Heart Myocytes
Published on: June 16, 2009
Structural localization and expression of CXCL12 and CXCR4 in rat heart and isolated cardiac myocytes
Audrey Segret1, Catherine Rücker-Martin, Catherine Pavoine
1CNRS-UMR 8162, Université Paris XI Sud, Hôpital Marie Lannelongue, 133 avenue de la Résistance, 92350 Le Plessis-Robinson, France. audrey.segret@ccml.u-psud.fr
Insights
Researchers identified the protein expression and location of CXCL12 (CXC-chemokine ligand 12) and CXCR4 (CXC-chemokine receptor type 4) in rat hearts. This finding is crucial for understanding heart function and disease.
Area of Science:
- Cardiovascular Biology
- Molecular Cardiology
- Cellular Signaling
Background:
- The CXCL12/CXCR4 axis is implicated in cardiac development and repair.
- While CXCL12 mRNA isoforms are known in the heart, protein expression and localization remain largely uncharacterized.
- Understanding this axis is vital for both normal cardiac physiology and pathophysiology.
Purpose of the Study:
- To investigate the protein expression and subcellular localization of CXCR4 and CXCL12 in the adult rat heart.
- To determine the specific isoforms of CXCR4 and CXCL12 present in cardiomyocytes.
- To elucidate the precise location of these proteins within cardiac cells.
Main Methods:
- Western blot analysis of isolated rat cardiomyocytes.
- Confocal microscopy for protein localization.
- Electron microscopy for ultrastructural analysis.
- Utilized a rat myocardial infarction model for in vivo relevance.
Main Results:
- Identified a specific 67-kDa CXCR4 isoform and a 12-kDa CXCL12 isoform in cardiomyocytes.
- CXCR4 was localized to the cardiomyocyte plasmalemma.
- CXCL12 was found in continuity with the Z-line, within the T-tubule system.
Conclusions:
- This study provides the first detailed description of CXCR4 and CXCL12 protein expression and localization in the rat heart.
- The findings suggest a potential role for the CXCL12/CXCR4 axis in regulating cardiomyocyte calcium homeostasis.
- Further research is warranted to fully decipher the functional significance of this axis in normal and diseased hearts.
Abstract:
CXCL12 (SDF-1), which binds CXCR4, is involved in several physiological and pathophysiological processes. In heart, this axis seems to play a key role in cardiogenesis and is involved in the neovascularization of ischemic tissues. Rats have three known CXCL12 mRNA isoforms, of which only alpha and gamma are present in the normal heart. However, little is known about CXCL12 protein expression and localization. We investigated the pattern of protein expression and the localization of both CXCR4 and CXCL12 in the heart, using isolated cardiomyocytes and a rat myocardial infarction model. Western blots showed that cardiomyocytes contained a specific 67-kDa CXCR4 isoform and a 12-kDa CXCL12 isoform. Confocal and electron microscopy clearly showed that CXCR4 was present at the plasmalemma and CXCL12 in continuity of the Z-line, in the proximal part of T-tubules. In conclusion, we provide the first description of the expression and fine localization of CXCR4 and CXCL12 proteins in normal rat heart and cardiomyocytes. These results suggest that the CXCL12/CXCR4 axis may be involved in cardiomyocyte calcium homeostasis regulation. Our work and the well-known chemoattraction properties of the CXCL12/CXCR4 axis highlight the importance of deciphering the function of this axis in both normal and pathological hearts.
