The story of DNase II: a stifled death-wish leads to self-harm

A young boy with rash, arthritis, and developmental delay: Monogenic lupus due to DNASE2 gene defect

Monogenic causes are increasingly being recognized in patients with lupus, especially in early-onset disease. We herein report a boy with a novel mutation in the DNase 2 (DNASE2) gene presenting with monogenic lupus. A 6-year-old boy with a global developmental delay with microcephaly presented with chronic febrile illness with anemia, rash, polyarthritis, renal involvement, and hepatosplenomegaly. Laboratory investigations revealed positive antinuclear antibody, high anti-dsDNA antibody titers, hypocomplementemia, hypergammaglobulinemia, nephrotic range proteinuria, and diffuse proliferative glomerulonephritis. Magnetic resonance imaging of brain showed altered signal intensity in subcortical white matter in bilateral fronto-parieto-temporal lobes. Targeted next-generation sequencing revealed a novel pathogenic variant in DNASE2. He was treated with oral prednisolone, mycophenolate mofetil, cyclosporine, and hydroxychloroquine and is doing well on follow up. DNASE2 deficiency has been reported as a rare genetic cause of monogenic lupus. DNASE2 deficiency should be suspected in patients with early-onset lupus with polyarthritis, erythematous rash, and neurological involvement.

Structures and Mechanisms in the cGAS-STING Innate Immunity Pathway

Besides its role as the blueprint of life, DNA can also alert the cell to the presence of microbial pathogens as well as damaged or malignant cells. A major sensor of DNA that triggers the innate immune response is cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) (cGAMP) synthase (cGAS), which produces the second messenger cGAMP. cGAMP activates stimulator of interferon genes (STING), which activates a signaling cascade leading to the production of type I interferons and other immune mediators. Recent research has demonstrated an expanding role of the cGAS-cGAMP-STING pathway in many physiological and pathological processes, including host defense against microbial infections, anti-tumor immunity, cellular senescence, autophagy, and autoimmune and inflammatory diseases. Biochemical and structural studies have elucidated the mechanism of signal transduction in the cGAS pathway at the atomic resolution. This review focuses on the structural and mechanistic insights into the roles of cGAS and STING in immunity and diseases revealed by these recent studies.

Whipworm genome and dual-species transcriptome analyses provide molecular insights into an intimate host-parasite interaction

Matthew Berriman and colleagues report the whole-genome sequences of the human-infective whipworm Trichuris trichiura and the mouse-infective laboratory model Trichuris muris. Their transcriptome analyses and examination of T. muris infection in mice provide insights into host response to infection and potential drug targets for this major soil-transmitted helminth.

Whipworms are common soil-transmitted helminths that cause debilitating chronic infections in man. These nematodes are only distantly related to Caenorhabditis elegans and have evolved to occupy an unusual niche, tunneling through epithelial cells of the large intestine. We report here the whole-genome sequences of the human-infective Trichuris trichiura and the mouse laboratory model Trichuris muris. On the basis of whole-transcriptome analyses, we identify many genes that are expressed in a sex- or life stage–specific manner and characterize the transcriptional landscape of a morphological region with unique biological adaptations, namely, bacillary band and stichosome, found only in whipworms and related parasites. Using RNA sequencing data from whipworm-infected mice, we describe the regulated T helper 1 (T_H1)-like immune response of the chronically infected cecum in unprecedented detail. In silico screening identified numerous new potential drug targets against trichuriasis. Together, these genomes and associated functional data elucidate key aspects of the molecular host-parasite interactions that define chronic whipworm infection.