Thanks to Sayandeep Saha, Brown Lab Team members, our collaborators, and funding agencies (this wouldn’t have been possible without the NIH!) #NIH @warfnews.bsky.social‬ ‪
@uwmadisonstemcell.bsky.social‬
@wiscsurgery.bsky.social‬
@morgridgeinstitute.bsky.social‬
www.the-brown-lab.com

We believe ICAM-1 KO PSC will serve as a platform technology, with applications in a number of disease areas. We are looking to collaborate with researchers investigating Parkinson’s, macular degeneration, and hematopoietic and other contexts that require MHC-replete cells.

ICAM-1 plays an important role in T1D pathogenesis, and we are eager to explore ICAM-1 KO PSC-islets as a new therapeutic candidate for T1D. pubmed.ncbi.nlm.nih.gov/37619906/

Our lab is exploring ICAM-1 KO PSCs for cardiovascular disease, as well as Type 1 diabetes (T1D). T1D is a particularly promising area for leveraging this hypoimmune technology, in light of recent clinical advances. www.nejm.org/doi/full/10....

Conventional hypoimmune PSC editing (e.g., MHC KO) can result in an adverse effect—NK cell missing self killing. Our editing approach leaves MHC intact, so we may avoid this adverse effect. Future studies in our lab will explore the role of NK cells against ICAM-1 KO cells.

ICAM-1 is a target involved in multiple aspects of the allograft rejection response, such as 1) immune synapse formation; 2) transendothelial migration; 3) cellular responses to external inflammatory oxidative stress. We are actively exploring these and other roles of ICAM-1 in our lab.

Use of the NeoThy is important for PSC immunogenicity studies, as other humanized mouse models besides the NeoThy and BLT lack human thymus incorporation and are suboptimal for assessing human MHC-restricted T cell responses. pubmed.ncbi.nlm.nih.gov/32588980/ pubmed.ncbi.nlm.nih.gov/37386161/

We transplanted ICAM-1 KO into next-generation NeoThy humanized mice and saw that the KO cells were retained, but wild type cells were dramatically reduced in size, indicating that the KOs are protected against allograft rejection in vivo.

ICAM-1 KO reduced binding of adaptive (e.g., T cells) and innate (e.g., neutrophils) immune cells. It also resulted in markedly diminished T cell activation and proliferation in vitro.

We successfully and reproducibly made three ICAM-1 knock out cardiovascular cell types (endothelial cells, cardiomyocytes, and cardiac fibroblasts) from multiple PSC lines, including induced PSCs and embryonic stem cells.

ICAM-1 is expressed on endothelial and other cells and is upregulated in response to post-transplantation inflammatory stimuli (e.g., TNFa, IFNg). There are cell surface and secreted forms of ICAM-1. Our KO prevented both types of protein from being expressed by the cells.

This work describes a new class of hypoimmune gene edit for pluripotent stem cell (PSC)-based therapies. We used CRISPR-Cas9 gene editing technology to knock out (KO) ICAM-1, an important cell adhesion molecule used by adaptive and innate immune cells mediating transplantation rejection.