detection of intracellular calcium signaling in the magnetically isolated vascular wall cd34+ stem cells

Isolation and Magnetic Separation of Murine CD34+ Stem Cells from the Vascular Wall

The vascular wall plays a pivotal role in vascular development, homeostatic regulation, and the progression of vascular diseases. In recent years, numerous studies have unveiled the presence of various stem cell lineages in arteries. In 2004, Professor Qingbo Xu&#39;s group first reported the existence of vascular stem/progenitor cells in the periphery of the adult vascular wall, expressing CD34, Sca-1, c-kit, and Flk-11. These vascular stem cells exhibit multidirectional differentiation and proliferation potential. Under normal conditions, they remain relatively quiescent; however, when activated by specific factors, they can differentiate into smooth muscle cells, endothelial cells, and fibroblasts. Alternatively, they can regulate the perivascular matrix and microvessel formation through paracrine effects to promote the repair or remodeling of injured vessels2,3,4,5,6. Recently, resident CD34+ stem cells in the vascular wall were found to play a role in endothelial cell regeneration after femoral artery guidewire injury2. Consequently, the isolation and quantification of CD34+ VW-SCs and the examination of the basic biological characteristics of CD34+ stem cells are crucial for further studying the signal pathways involved in the regulation of CD34+ VW-SCs.
Various methods for cell separation are currently available, including techniques based on cell culture characteristics or physical properties of cells such as density gradient centrifugation, which results in sorted cells containing many non-target cells and relatively low purity7,8,9,10,11,12. Another commonly used technique is fluorescence/magnetic-assisted cell sorting. Fluorescence-activated cell sorting (FACS) is a complex system with high technical requirements, and it is relatively expensive, time-consuming, and potentially affects the activity of sorted cells13,14. However, magnetic-activated cell sorting (MACS) is more efficient and convenient, with a high recovery rate and cell activity and less impact on downstream applications8. Therefore, in this protocol, we applied MACS to purify CD34+ VW-SCs and further identified the cells by flow cytometry. The establishment of MACS-based isolation methods for studying vascular wall stem cells would be invaluable. Firstly, it permits experimental genetic and cell biological studies. Secondly, efficient isolation and culture of vascular wall resident stem cells allow systematic assessment and screening of signaling factors regulating stem cell functions. Thirdly, identification of crucial phenotypes in stem cells provides important &#39;quality control&#39; in assessing cell status. Thus, identifying methods to purify could be useful for similar applications to analogous stem cells derived from vessels.
This report provides a detailed demonstration of a stable and reliable method for the culture of CD34+ VW-SCs, including cell identification and functional assessment performed by flow cytometry, immunofluorescence staining, and Ca2+ signaling measurement. This study provides a basis for further in-depth research on the function of CD34+ VW-SCs and their regulatory mechanisms in physiological and pathological conditions.

Author Spotlight: Enhanced Isolation and Characterization of Vascular Wall Resident Murine CD34+ Stem Cells Using Magnetic Bead Screening-Coupled Flow Cytometry

Immunomagnetic Isolation of the Vascular Wall-Resident CD34+ Stem Cells from Mice

Resident vascular wall CD34+stem cells are increasingly recognized for their crucial role in regulating vascular remodeling post-injury. Establishing a stable and efficient method to culture functional CD34+cells is essential for further investigating the participating mechanisms under various physiological and pathological conditions. This technique combines magnetic bead screening and flow cytometry to purify the primary cultured resident CD34+stem cells.Then, the purified cells can be functionally identified through immunofluorescent staining and calcium imaging. Due to the phenotypical and functional heterogeneity of resident CD34+stem cells in the vascular nerve wall, it will be necessary to identify the specific subcellular type of resident vascular CD34+cells. We present a refined methodology for the culture, identification, and the functional assessment of vascular wall-resident CD34+stem cells.This novel approach encompasses magnetic sorting, flow cytometry, immunofluorescence staining, and calcium signaling measurement. By employing these techniques, our study establishes a solid foundation for the future comprehensive investigations into the function under regulation of recipient CD34+stem cells under both physiological and pathological conditions.

Detection of Intracellular Calcium Signaling in the Magnetically Isolated Vascular Wall CD34+ Stem Cells

To begin, isolate the resident vascular wall CD34-positive stem cells from murine models. Obtain pure cells by magnetic activated cell sorting and characterize them. For detecting calcium signaling, obtain a coverslip pre-seeded with the cells and wash it once with PBS.Then incubate the cells with Fura 2-AM and Tyrode solution for 30 minutes in the dark. To remove the dye, incubate the cells with Tyrode solution for 10 minutes. Then mount the chamber on the stage of an inverted fluorescence microscope, open the main window and go to the grab settings dialogue and camera page.Press the live button for the live image display. To acquire images, draw several freehand lines to circle the cells with different colors and predefine the regions of interest. Fluorescence microscopy demonstrated that ATP administration increased the intracellular calcium levels in the isolated vascular wall CD34-positive stem cells.

Research

JoVE Journal

Medicine

Resident CD34+ vascular wall-resident stem and progenitor cells (VW-SCs) are increasingly recognized for their crucial role in regulating vascular injury ...

Murine Aortal and Mesenteric Arteries Isolation and Culture to Separate CD34+ Stem Cells for Cardiovascular Studies

Magnetic Separation of Vascular Wall-Resident CD34+ Stem Cells Isolated from Murine Aortal and Mesenteric Arteries for Cardiovascular Studies

Characterization of the Magnetically Isolated CD34+ Stem Cells for Cardiovascular Studies