Our research - Lisa Westerberg group

The overall goal of our research is to understand how a compromised immune system leads to immunodeficiency with high incidence of autoimmunity and hematological cancers. We have a particular focus on how inborn mutations in actin regulators affect immune cell-cell communication, trafficking, and maintenance of genomic stability. Our research aims at revealing critical mechanisms for correct regulation of the immune system in health and disease and to identifying new targets for therapy.

Neutrophils by scanning electron microscopy
Neutrophils by scanning electron microscopy by Marton Keszei

Understanding the Immune system by studying Immunodeficiency Diseases

Primary immunodeficiencies are diseases in which part of the body's immune system is missing or does not function properly. Most primary immunodeficiencies are genetic disorders and the majority are diagnosed in children under the age of one. Translational studies of primary immunodeficiency diseases in patients and gene-targeted experimental models have increased our understanding of critical mechanisms for correct function of the immune system and have revealed novel therapeutic approaches.

A picture of the germinal center (pink-yellow) in B cell follicles (blue) in the spleen.
Germinal center (pink-yellow) in B cell follicles (blue) in the spleen by Carin Dahlberg

A journey from the cytoplasm to the nucleus with actin regulators in immune cells

We have focused on understanding the role of the evolutionary conserved WASp family of actin regulators and their interacting partners in immune cells. WASp is uniquely expressed in hematopoietic lineage cells and is mutated in two severe immunodeficiency diseases. Wiskott-Aldrich syndrome is caused by loss-of-function mutations in WASp and patients suffer from life-threating infections, thrombocytopenia, and are at risk to develop autoimmunity and cancer. In contrast to WAS, X-linked neutropenia (XLN) is caused by gain-of-function mutations predicted to lead to a constitutively-active WASp. XLN patients suffer from severe congenital neutropenia and are at risk to develop malignancies.

High resolution images for F-actin (blue) in B cells
High resolution images for F-actin (blue) in B cells by Mezida Saeed

Recent data from our group and other groups challenges the view that WASp deficiency leads to hypo-responsive immune cells. Instead, our data suggests that WASp-associated immunodeficiency leads to a breach in tolerance by activation of the ‘wrong’ cells at incorrect sites (Kritikou et al, JCI Insight 2021; Keszei et al, J Clin Invest 2018; Baptista et al, Nat Comms 2016). Using patient samples and experimental models, we are currently investigating how WASp and its interacting partners coordinate receptor signal to gene transcription and chromatin remodeling in the nucleus. A focus is the role of nuclear localization of WASp family members and actin in immune cells (Kuznetov et al, Genome Med 2017). We here combine advanced tissue culture assays and flow cytometry, unique molecular biology tools, and high resolution microscopy.

A microscope picture of TIRF B cells with myosin.
TIRF B cells with myosin by Mezida Saeed

Immunodeficiency and lymphoma – two sides of the same coin?

We are using gene editing techniques of immune cells to understand the relation of cell transformation and specific genetic mutations identified in primary immunodeficiency patients and lymphoma patients. By analysis of the actin sensor MKL1/MRTFA, we found that its overactivity leads to changed expression of integrins and decreased cell-to-cell contact. This was associated with increased cell proliferation, genomic instability and lymphoma cell growth in vitro and in vivo (Record et al, Haematologica 2020). Increased activity of WASp in X-linked neutropenia leads to aberrant cell division and genomic instability of B cells and, interestingly, is associated with generation of more terminally differentiated plasma cells (He et al, J Allergy Clin Immunol 2021; Westerberg et al, J Exp Med 2010). We are using and collecting samples from primary immunodeficiency patients and pediatric lymphoma patients to understand clonal events at single cell level that lead to cell transformation.

An illustration of mission patch
Mission patch, by Julien Record.

Finding new treatments based on experimental research

Based on our findings, we are testing if modulating actin regulators can be used in therapeutic approaches for Wiskott-Aldrich syndrome and in personalized and generalized cancer immune therapy. We here make use of ex vivo drug screening combined with in vivo experimental models.

Immunodeficiency in extreme environments

Using our knowledge and methodology from studies of primary immunodeficiency and lymphoma patients, we have started to collect cells and samples from volunteers exposed to short term and long term loss of gravity (microgravity).  We are using transcriptomics and proteomics combined with high resolution microscopy to understand how immune cells and the immune system are affected in the absence of gravity.

Content reviewer:
Sara Lidman