Macrophage efferocytosis in Cardiac Repair

We are testing whether enhancing efferocytosis can benefit heart repair after myocardial infraction?

Finding new regulators for Macrophage efferocytosis

Can WDFY3 serve as an effective therapeutic target in resolving autoinflammation?

  1. Efficient efferocytosis is essential for maintaining homeostasis. Excessive apoptotic cell (AC) death and impaired macrophage efferocytosis lead to autoantigen release and autoantibody production, immune activation, and organ damage.
  2. It remains unclear whether these immunogenic autoantigens are the sole cause of increased autoimmunity or if efferocytosis of ACs directly influences macrophage function, impacting their ability to activate T cells and potentially amplifying autoimmune responses. Additionally, it has not been established if enhancing macrophage efferocytosis or modulating macrophage responses to AC engulfment can be protective in autoimmune-like disorders.
  3. Our previous work showed WDFY3 is crucial for efficient macrophage efferocytosis.
  4. This study reveals that myeloid knockout of Wdfy3 exacerbates autoimmunity in young mice with increased AC burden by systemic injections of ACs and in middle-aged mice developing spontaneous autoimmunity, whereas ectopic overexpression of WDFY3 suppresses autoimmunity in these models. 
  5. This work uncovered the role of WDFY3 as a protector against autoimmunity by promoting macrophage efferocytosis thus limiting autoantigen production, as well as mitigating T cell activation and inflammasome activation. 

How we find WDFY3 as a novel regulatory gene to improve efferocytosis? 

1. In this study, we developed a genome-wide CRISPR knockout screen in primary macrophages.

2. By focusing on efferocytosis, a complex macrophage functional phenotype, we illustrated the versatility of pooled screens and provided an effective approach for genome-wide CRISPR screening in primary macrophages derived from Cas9 transgenic mice.

3. We have identified many known genes regulating efferocytosis and general phagocytosis, illuminating the most important genes essential for the uptake of ACs during efferocytosis.

4. We have also uncovered and validated WDFY3 as a novel regulator specifically regulating the phagocytosis of dying cells, but not other substrates, using orthogonal assays in vitro and in vivo. Mechanistically, WDFY3 deficiency led to impaired phagosome formation due to defects in actin depolymerization. We further revealed that WDFY3 directly interacts with GABARAP, one of the seven members of the LC3/GABARAP protein family, to facilitate LC3 lipidation and the efficient degradation of the engulfed cargo.