Mutation in DNAse1L3 triggers systemic lupus erythematosus (SLE)-like condition in mice

Autoimmune disease, as word implies, is an immune response directed to self. Traditionally we used to think that autoimmune diseases arise as a result of failure of adaptive immune system (T and B cells) to distinguish between self and nonself antigens. However, as with many inherited immunodeficiencies, frequently we see that inherited innate genetic mutations play pivotal part in autoimmune phenotypes as well.  

For example, few days ago journal Cell published study showing that mice deficient for DNAse1L3, an enzyme capable of degrading extracellular chromatin associated DNA, develop systemic lupus erythematosus (SLE)-like condition.

DNAse1L3, a homologue to DNAse1, contains a short, positively charged C-terminal peptide that allows it to uniquely digest DNA chromatin in microparticles released from apoptotic cells.

Mice deficient for DNAse1L3 develop anti-dsDNA Ab response and Ab deposition in the kidney glomeruli [clinical feature of SLE in humans].

Unlike other genetic DNA/RNA housekeeping mutations (Trex1^-/-, DNase-II^-/-, RNase H2B^-/- ) phenotype of DNAse1L3-KO mice was independent of STING activity (but was dependent on MyD88, though was not clear how or why).

In summary, This study revealed that DCs/Mac derived secreted DNAse1L3 is intimately involved in digestion of apoptotic microparticle associated DNA and in prevention of anti-DNA antibody formation (of note, one of the authors is a co-founder and consultant of Resolve Therapeutics, which develops soluble nucleases for therapeutic purposes).

David Usharauli