Adverse mental health outcomes in a population-based cohort of survivors of childhood cancer.

BACKGROUND: The elevated risk for physical late effects in childhood cancer survivors (CCS) is well documented, but their risk for mental health problems is less well described. METHODS: The authors assembled a cohort of all 5-year CCS who were diagnosed before age 18 years and treated in an Ontario pediatric cancer center between 1987 and 2008. Patients were matched to population controls and linked to health administration databases. The authors calculated rates of mental health care visits (family physician, psychiatrist, emergency department, hospitalization) and the risk for a severe mental health event (emergency department, hospitalization, suicide). Outcomes were compared using recurrent event and survival analyses. RESULTS: Compared with 20,269 controls, 4117 CCS had a higher rate of mental health visits (adjusted relative rate [RR], 1.34; 95% confidence interval [CI], 1.12-1.52). Higher rates were associated with female gender (RR, 1.39; CI, 1.10-1.75; P = .006) and being diagnosed at ages 15 to 17.9 years (compared with ages 0-4 years: RR, 1.81; 95% CI, 1.17-2.80; P = .008). Cancer type, treatment intensity, and treatments targeting the central nervous system were not significant predictors. Survivors were at increased risk for a severe event compared with controls (adjusted hazard ratio, 1.13; 95% CI, 1.00-1.28; P = .045). CCS who were diagnosed with cancer at age 4 years or younger were at greatest risk: 16.3% (95% CI, 13.2%-19.8%) had experienced a severe event by age 28 years. CONCLUSIONS: CCS experienced higher rates of mental health visits and a greater risk for a severe event than the general population. Survivors of adolescent cancer have a higher rate of mental health visits overall, whereas survivors of cancer before age 4 years have a markedly elevated risk of severe events. Cancer 2018;124:2045-57. © 2018 American Cancer Society.

The mammalian-membrane two-hybrid assay (MaMTH) for probing membrane-protein interactions in human cells.

Cell signaling, one of key processes in both normal cellular function and disease, is coordinated by numerous interactions between membrane proteins that change in response to stimuli. We present a split ubiquitin-based method for detection of integral membrane protein-protein interactions (PPIs) in human cells, termed mammalian-membrane two-hybrid assay (MaMTH). We show that this technology detects stimulus (hormone or agonist)-dependent and phosphorylation-dependent PPIs. MaMTH can detect changes in PPIs conferred by mutations such as those in oncogenic ErbB receptor variants or by treatment with drugs such as the tyrosine kinase inhibitor erlotinib. Using MaMTH as a screening assay, we identified CRKII as an interactor of oncogenic EGFR(L858R) and showed that CRKII promotes persistent activation of aberrant signaling in non-small cell lung cancer cells. MaMTH is a powerful tool for investigating the dynamic interactomes of human integral membrane proteins.

A key role for ATF3 in regulating mast cell survival and mediator release.

Activating transcription factor 3 (ATF3) is a basic leucine zipper transcription factor that plays a regulatory role in inflammation, cell division, and apoptosis. Mast cells (MCs) initiate many inflammatory responses and have a central role in allergy and allergic diseases. We report here that ATF3 has a central role in MC development and function. Bone marrow-derived MC populations from ATF3-deficient mice are unresponsive to interleukin-3 (IL-3)-induced maturation signals, and this correlates with increased apoptosis, diminished activation of the Akt kinase, and decreased phosphorylation of the proapoptotic protein Bad. Furthermore, ATF3-null mice lacked MCs in the peritoneum and dermis, showing that the in vitro results are recapitulated in vivo. ATF3-null MCs also showed functional defects; high-affinity immunoglobulin E receptor-mediated degranulation was significantly inhibited, whereas IL-4 and IL-6 expression was enhanced. This dual role of ATF3 provides insight into the complex interplay between MC development and its subsequent physiologic role.

A common human TLR1 polymorphism regulates the innate immune response to lipopeptides.

Toll-like receptors (TLR) are critical mediators of the immune response to pathogens and human polymorphisms in this gene family regulate inflammatory pathways and are associated with susceptibility to infection. Lipopeptides are present in a wide variety of microbes and stimulate immune responses through TLR1/2 or TLR2/6 heterodimers. It is not currently known whether polymorphisms in TLR1 regulate the innate immune response. We stimulated human whole blood with triacylated lipopeptide, a ligand for TLR1/2 heterodimers, and found substantial inter-individual variation in the immune response. We sequenced the coding region of TLR1 and found a non-synonymous polymorphism, I602S (base pair T1805G), that regulated signalling. In comparison to TLR1_602S, the 602I variant mediated substantially greater basal and lipopeptide-induced NF-kappaB signalling in transfected HEK293 cells. These signalling differences among TLR1 variants were also found with stimulation by extracts of Mycobacterium tuberculosis. Furthermore, individuals with the 602II genotype produced substantially more IL-6 than those with the 602SS variant in a lipopeptide-stimulated whole-blood cytokine assay. Together, these observations demonstrate that variation in the inflammatory response to bacterial lipopeptides is regulated by a common TLR1 transmembrane domain polymorphism that could potentially impact the innate immune response and clinical susceptibility to a wide spectrum of pathogens.

Cutting edge: Tlr5-/- mice are more susceptible to Escherichia coli urinary tract infection.

Although TLR5 regulates the innate immune response to bacterial flagellin, it is unclear whether its function is essential during in vivo murine infections. To examine this question, we challenged Tlr5(-/-) mice transurethrally with Escherichia coli. At 2 days postinfection, wild-type mice exhibited increased inflammation of the bladder in comparison to Tlr5(-/-) mice. By day 5 postinfection, Tlr5(-/-) mice had significantly more bacteria in the bladders and kidneys in comparison to wild-type mice and showed increased inflammation in both organs. In addition, flagellin induced high levels of cytokine and chemokine expression in the bladder that was dependent on TLR5. Together, these data represent the first evidence that TLR5 regulates the innate immune response in the urinary tract and is essential for an effective murine in vivo immune response to an extracellular pathogen.

A common dominant TLR5 stop codon polymorphism abolishes flagellin signaling and is associated with susceptibility to legionnaires' disease.

Although Toll-like receptors (TLRs) are critical mediators of the immune response to pathogens, the influence of polymorphisms in this gene family on human susceptibility to infection is poorly understood. We demonstrated recently that TLR5 recognizes flagellin, a potent inflammatory stimulus present in the flagellar structure of many bacteria. Here, we show that a common stop codon polymorphism in the ligand-binding domain of TLR5 (TLR5392STOP) is unable to mediate flagellin signaling, acts in a dominant fashion, and is associated with susceptibility to pneumonia caused by Legionella pneumophila, a flagellated bacterium. We also show that flagellin is a principal stimulant of proinflammatory cytokine production in lung epithelial cells. Together, these observations suggest that TLR5392STOP increases human susceptibility to infection through an unusual dominant mechanism that compromises TLR5's essential role as a regulator of the lung epithelial innate immune response.