Hypercytokinemia is a critically fatal factor in COVID-19. However, underlying pathogenic mechanisms are unknown. Here we show that brinogen and leukotriene-A4 hydrolase (LTA4H), two of the most potent in ammatory contributors, are elevated by 67.7 and astonishing 227.7% in the plasma of patients infected by SARS-CoV-2 and admitted to intensive care unit in comparison with healthy control, respectively. Conversely, transferrin identi ed as a brinogen immobilizer in our recent work and Spink6 are down-regulated by 40.3 and 25.9%, respectively. Furthermore, we identify Spink6 as the rst endogenous inhibitor of LTA4H, a pro-in ammatory enzyme catalyzing nal and rating limited step in biosynthesis of leukotriene-B4 that is an extremely in ammatory mediator and a target to design superior anti-in ammatory drugs. Additionally, virus Spike protein is found to evoke LTA4H and brinogen expression in vivo. Collectively, these ndings identify the imbalance between in ammatory drivers and antagonists, which likely contributes to hypercytokinemia in COVID-19. Spink6 may have superior antiin ammatory function because it speci cally targets epoxide hydrolase of LTA4H to inhibit leukotriene-B4 biosynthesis without effecting LTA4H's aminopeptidase activity.

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Tumor invasion and metastasis are the main causes of death from cancer. Epithelial to mesenchymal transition (EMT) is a determining step for a cancer cell to progress from a noninvasive to invasive state. Krüppel-like factor 8 (KLF8) plays a key role in oncogenic transformation and is highly overexpressed in several types of invasive human cancer, including breast cancer. To understand the role of KLF8 in regulating the progression of human breast cancer, we first established stable expression of KLF8 in an immortalized normal human breast epithelial cell line. We found that KLF8 strongly induced EMT and enhanced motility and invasiveness in the cells, by analyzing changes in cell morphology and epithelial and mesenchymal marker proteins, and using cell migration and Matrigel invasion assays. Chromatin immunoprecipitations (ChIP), oligonucleotide precipitations, and promoter-reporter assays showed that KLF8 directly bound and repressed the promoter of E-cadherin independent of E boxes in the promoter and Snail expression. Aberrant elevation of KLF8 expression is highly correlated with the decrease in E-cadherin expression in the invasive human breast cancer. Blocking KLF8 expression by RNA interference restored E-cadherin expression in the cancer cells and strongly inhibited the cell invasiveness. This work identifies KLF8 as a novel EMT-regulating transcription factor that opens a new avenue in EMT research and suggests an important role for KLF8 in human breast cancer invasion and metastasis. [Cancer Res 2007;67(15):7184-93]

Immunity against new infections declines in the last quartile of life, as do numbers of naive T cells. Peripheral maintenance of naive T cells over the lifespan is necessary because their production drastically declines by puberty, a result of thymic involution. We report that this maintenance is not random in advanced aging. As numbers and diversity of naive CD8 + T cells declined with aging, surviving cells underwent faster rates of homeostatic proliferation, were selected for high T-cell receptor: pMHC avidity, and preferentially acquired "memory-like" phenotype. These high-avidity precursors preferentially responded to infection and exhibited strong antimicrobial function. Thus, T-cell receptor avidity for self-pMHC provides a proofreading mechanism to maintain some of the fittest T cells in the otherwise crumbling naive repertoire, providing a degree of compensation for numerical and diversity defects in old T cells.lymphocyte homeostasis | T-cell repertoire | CD8 T cells

Key Points Question Can multiparametric magnetic resonance imaging (MRI) radiomic profiles be used to predict axillary lymph node metastasis (ALNM) and disease-free survival (DFS) in patients with early-stage breast cancer? Findings In this prognostic study that included 1214 patients, 2 clinical-radiomic nomograms were developed that accurately predicted ALNM and stratified patients into low-risk and high-risk groups for DFS. Meaning In this study, clinical-radiomic nomograms were useful in clinical decision-making associated with personalized selection of surgical interventions and therapeutic regimens for patients with early-stage breast cancer.