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Background: Pancreatic cancer stem cells (CSCs) promote pancreatic ductal adenocarcinoma (PDAC) tumorigenesis and chemoresistance. Cyclin-dependent kinase 1 (CDK1) plays an important role in tumor initiation in other tumors, but the function of CDK1 in PDAC remains unclear. Fisetin is a bioactive flavonoid with anti-tumor properties in multiple tumors, while its function in CSCs remains elusive. Results: In this study, we demonstrated that CDK1 was correlated with prognosis and was highly expressed in pancreatic cancer tissue and gemcitabine-resistant cells. Silencing CDK1 impaired tumor stemness and reduced a subset of CSCs. We found that fisetin blocked the kinase pocket domain of CDK1 and inhibited pancreatic CSC characteristics. Using acetylation proteomics analysis and phosphorylation array assay, we confirmed that fisetin reduced CDK1 expression and increased CDK1 acetylation at lysine 33 (K33), which resulted in the suppression of CDK1 phosphorylation. Silencing CDK1 or STAT3 suppressed tumor stemness properties, while overexpressing CDK1 or STAT3 showed the opposite effect. Mutation or acetylation of CDK1 at K33 weakened STAT3 phosphorylation at Y705, impairing the expression of stem-related genes and pancreatic cancer stemness. In addition, lack of histone deacetylase 3 (HDAC3), which deacetylates CDK1, contributed to weakening STAT3 phosphorylation by regulating the post-translational modification of CDK1, thereby decreasing the stemness of PDAC. Moreover, our results revealed that fisetin enhanced the effect of gemcitabine through eliminating a subpopulation of pancreatic CSCs by inhibiting the CDK1–STAT3 axis in vitro and in vivo. Conclusion: Our findings highlight the role of post-translational modifications of CDK1–STAT3 signaling in maintaining cancer stemness of PDAC, and indicated that targeting the CDK1–STAT3 axis with inhibitors such as fisetin is a potential therapeutic strategy to diminish drug resistance and eliminate PDAC. [ABSTRACT FROM AUTHOR]

Background: CD34+ cells have been used to treat the patients with heart failure, but the outcome is variable. It is of great significance to scrutinize the fate and the mechanism of CD34+ cell differentiation in vivo during heart failure and explore its intervention strategy. Methods: We performed single-cell RNA sequencing (scRNA-seq) of the total non-cardiomyocytes and enriched Cd34-tdTomato+ lineage cells in the murine (male Cd34-CreERT2; Rosa26-tdTomato mice) pressure overload model (transverse aortic constriction, TAC), and total non-cardiomyocytes from human adult hearts. Then, in order to determine the origin of CD34+ cell that plays a role in myocardial fibrosis, bone marrow transplantation model was performed. Furthermore, to further clarify the role of CD34 + cells in myocardial remodeling in response to TAC injury, we generated Cd34-CreERT2; Rosa26-eGFP-DTA (Cre/DTA) mice. Results: By analyzing the transcriptomes of 59,505 single cells from the mouse heart and 22,537 single cells from the human heart, we illustrated the dynamics of cell landscape during the progression of heart hypertrophy, including CD34+ cells, fibroblasts, endothelial and immune cells. By combining genetic lineage tracing and bone marrow transplantation models, we demonstrated that non-bone-marrow-derived CD34+ cells give rise to fibroblasts and endothelial cells, while bone-marrow-derived CD34+ cell turned into immune cells only in response to pressure overload. Interestingly, partial depletion of CD34+ cells alleviated the severity of myocardial fibrosis with a significant improvement of cardiac function in Cd34-CreERT2; Rosa26-eGFP-DTA model. Similar changes of non-cardiomyocyte composition and cellular heterogeneity of heart failure were also observed in human patient with heart failure. Furthermore, immunostaining showed a double labeling of CD34 and fibroblast markers in human heart tissue. Mechanistically, our single-cell pseudotime analysis of scRNA-seq data and in vitro cell culture study revealed that Wnt-β-catenin and TGFβ1/Smad pathways are critical in regulating CD34+ cell differentiation toward fibroblasts. Conclusions: Our study provides a cellular landscape of CD34+ cell-derived cells in the hypertrophy heart of human and animal models, indicating that non-bone-marrow-derived CD34+ cells differentiating into fibroblasts largely account for cardiac fibrosis. These findings may provide novel insights for the pathogenesis of cardiac fibrosis and have further potential therapeutic implications for the heart failure. [ABSTRACT FROM AUTHOR]

Background: Extracorporeal blood purification therapies targeting removal of the downstream products of the inflammatory cascade in sepsis have failed to improve mortality. As an upstream process of the inflammatory cascade, activated white blood cells should be a potential therapeutic target for sepsis, and the effect of removing such cells by extracorporeal centrifugal leukocytapheresis (LCAP) is worth considering.Methods: Fourteen peritonitis-induced septic pigs were randomly assigned to receive a sham operation (control group, n = 7) or one session of LCAP at 12 h after sepsis induction (treatment group, n = 7). Samples from peripheral blood at various time-points and from LCAP collection were tested. All pigs were euthanized at 48 h, and lung, kidney, liver and spleen tissues were obtained for histopathological examination.Results: Two pigs died in accidents before the induction of sepsis, and 12 pigs were finally included for the statistical analysis. A significant clinical improvement was present in the treatment group relative to the control group in terms of the mean arterial blood pressure (MAP), oxygen tension (PaO2), lactic acid level, oxygenation index (PaO2/FiO2), and carbon dioxide tension (PaCO2, P < 0.05). Flow cytometry tests showed that a mixture of B cells, dendritic cells, T helper cells, cytotoxic T cells, monocytes and neutrophils were removed from the circulation by LCAP, resulting in sepsis-induced change trends in the control cells; these change trends were all flattened in the treatment group, although nonsignificantly.Conclusions: LCAP may exert a wide-spectrum and bidirectional immunomodulatory effect on sepsis, accompanied by improvements in hemodynamics and oxygenation status. [ABSTRACT FROM AUTHOR]

Background: Patients with systemic lupus erythematosus (SLE) are highly susceptible to infection and cardiovascular events, suggesting that chronic antigenic stimulation may accelerate premature aging in SLE patients. Premature aging in SLE is often accompanied with the expansion of cytotoxic CD4 + CD28−T cells. Damage caused by CD4 + CD28− T cells enhances the progressive aging of the tissue function and loss of organism's fitness. The high serum level of IL-15 has been implicated in the pathogenesis of SLE, but its role in CD4 + CD28−T cell-mediated cytotoxicity in nephritic SLE remains unclear. The aim of this study was to investigate the effect of IL-15 on functional properties and associated renal damage of cytotoxic CD4 + CD28− T cell in lupus nephritis (LN). Results: Flow cytometry showed that the number of circulating innate-like CD4 + CD28− T cells was increased in patients with nephritic SLE. Immunofluorescence showed CD4 + CD28− T cell infiltration in the kidney of LN patients, which was correlated with multiple clinicopathological features including estimated glomerular filtration rate (eGFR), proteinuria, the proportion of glomerulosclerosis and the degree of renal chronicity. In addition, a high level of IL-15 and IL15-expressing macrophage infiltration was detected in the periglomerular and intraglomerular tissues of LN patients, which enhanced the innate features, cytokine secretion and migratory capability of CD4 + CD28− T cells, and finally exerted direct TCR-independent cytotoxicity on glomerular endothelial cells in an IL-15-dependent manner in vitro. Conclusion: Our study demonstrated that excessive IL-15 potentially promoted cytotoxic CD4 + CD28− T cell-mediated renal damage in LN. This finding may provide new insights into the potential association of premature aging and tissue damage in LN. [ABSTRACT FROM AUTHOR]