Mural cells are the supportive cells of the circulatory system's blood vessels. They are a heterogeneous group, primarily consisting of two cell types: vascular smooth muscle cells (vSMCs) and pericytes. These cells are found in close contact with the blood vessels' walls and play a vital role in maintaining the vessel's structure and function.
Key Roles of Mural Cells:
- Regulation of Blood Pressure and Flow: Mural cells help control blood pressure and blood flow distribution throughout the body. This is achieved through their ability to contract and relax the blood vessel walls.
- Structural Integrity of Blood Vessels: They contribute significantly to the structural integrity and stability of the vascular wall.
- Vascular Development: Mural cells participate actively in the development and growth of new blood vessels (angiogenesis).
- Blood-Brain Barrier (BBB) Function: In the brain, pericytes (a type of mural cell) are crucial for the proper functioning of the blood-brain barrier, a protective mechanism that regulates the passage of substances between the blood and the brain.
Types of Mural Cells:
- Vascular Smooth Muscle Cells (vSMCs): These cells are responsible for the contractile properties of larger blood vessels, influencing blood pressure and flow.
- Pericytes: These cells are found on smaller blood vessels, particularly capillaries, and are crucial for regulating vascular development, stability, and BBB function. They are increasingly recognized as having diverse functions, extending beyond simply supporting endothelial cells.
Further Research and Applications:
Recent research uses single-cell analyses to identify mural cells, for example, those expressing CD19 in the brain, offering potential targets for advanced therapies like CAR-T immunotherapy. Additionally, induced pluripotent stem cells (iPSCs) are being used to create in vitro models of mural cells to study diseases like CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy).
The study of mural cells continues to expand, revealing their diverse roles in health and disease, and making them promising therapeutic targets for various conditions affecting the circulatory system.
