Author ORCID Identifier
Date of Graduation
Masters of Science (MS)
Dr. Sean I. Savitz
Dr. Jaroslaw Aronowski
Dr. Matthew T. Harting
Dr. Harry Karmouty-Quintana
Dr. David W. Marshak
Dr. Scott D. Olson
Background: Ischemic stroke is a leading cause of death and long-term disability
around the world. Current treatment options are limited to the administration of
tissue plasminogen activator (tPA) and/or endovascular therapy, administered within
a limited time window. However, cell-based therapies such as mesenchymal stromal
cells (MSCs) have increasingly shown great promise for ischemic stroke recovery
with some therapies already in various stages of clinical trials. Intravenous (IV)
administration of the MSCs leads to the entrapment of these MSCs in the lungs.
These entrapped MSCs interact with the pulmonary endothelial cells (PECs) and
could modulate the immune response through the release of cytokines and
chemokines. Monocyte Chemoattractant Protein - 1 (MCP-1), is an important
chemokine involved in the recruitment of monocytes and macrophages. In our study,
we wanted to explore the interactions between MSCs with PECs and how this
interaction changes the expression levels of MCP-1 and other cytokines after an
inflammatory event such as stroke. We also wanted to see if MCP-1 released
through the interaction between MSCs and PECs under inflammatory conditions,
modulates the immune response through the modification of monocytes.
Methods: Cultured murine PECs were grown either alone or in a combination of
murine MSCs, and were exposed to 1) a combination of IFN-γ and TNF-α
inflammatory stimuli or 2) Anti MCP-1 antibody to neutralize any secreted MCP-1.
The secretome release of IL-1β, IL-1ra, IL-6, MCP-1, and VEGF were analyzed
using ELISA (BD Biosciences and R&D Systems). To further understand the
immunomodulatory response, the collected media from the previous step was added
to splenic immune cells (CD11b+) and splenic monocytes (CD115+). The secretome
release was analyzed from these cells using ELISA.
Results: MCP-1 secretion levels were increased from PECs as well as co-cultures
of PECs and MSCs when they were exposed to inflammatory stimuli. When
cocultures of PECs and MSCs were exposed to recombinant MCP-1 or MCP-1
neutralizing antibody, VEGF secretion levels decreased. In the presence of
inflammatory stimuli, co-cultures of PECs and MSCs secreted elevated levels of
VEGF. While under inflammation, we also observed that IL-6 levels were elevated
and they remain elevated even when MCP-1 was neutralized. We did not observe
any difference in secretome release from neither the splenic immune cells (CD11b+)
nor the splenic monocytes (CD115+).
Conclusion: Our data show that MCP-1 release under stroke-like conditions is
modulated through the interaction of PECs and MSCs. However, our study was
unable to elucidate MCP-1’s role in the modification of monocytes.
Stroke, Cell Therapy, Mesenchymal Stromal Cells, Pulmonary Endothelial Cells, Immunomodulation, Monocytes, MCP-1, IL-6, VEGF
Available for download on Tuesday, April 27, 2021