Renal fibrosis is widely considered a common mechanism leading to end-stage renal failure. Epithelial-to-mesenchymal transition (EMT) plays important roles in the pathogenesis of renal fibrosis. Runt-related transcription factor 1(RUNX1) plays a vital role in hematopoiesis via Endothelial-to-Hematopoietic Transition (EHT), a process that is conceptually similar to EMT, but its role in EMT and renal fibrosis is unclear. Here, we demonstrate that RUNX1 is overexpressed in the processes of TGF-β-induced partial EMT and renal fibrosis and that the expression level of RUNX1 is SMAD3-dependent. Knockdown of RUNX1 attenuated both TGF-β-induced phenotypic changes and the expression levels of EMT marker genes in renal tubular epithelial cells (RTECs). In addition, overexpression of RUNX1 promoted the expression of EMT marker genes in renal tubular epithelial cells. Moreover, RUNX1 promoted TGF-β-induced partial EMT by increasing transcription of the PI3K subunit p110δ, which mediated Akt activation. Specific deletion of Runx1 in mouse RTECs attenuated renal fibrosis, which was induced by both unilateral ureteral obstruction (UUO) and folic acid (FA) treatment. These findings suggest that RUNX1 is a potential target for preventing renal fibrosis.

An appropriate inflammatory response plays critical roles in eliminating pathogens, whereas an excessive inflammatory response can cause tissue damage. Runt-related transcription factor 1 (RUNX1), a master regulator of hematopoiesis, plays critical roles in T cells; however, its roles in Toll-like receptor 4 (TLR4)-mediated inflammation in macrophages are unclear. Here, we demonstrated that upon TLR4 ligand stimulation by lipopolysaccharide (LPS), macrophages reduced the expression levels of RUNX1 Silencing of Runx1 attenuated the LPS-induced IL-1β and IL-6 production levels, but the TNF-α levels were not affected. Overexpression of RUNX1 promoted IL-1β and IL-6 production in response to LPS stimulation. Moreover, RUNX1 interacted with the NF-κB subunit p50, and coexpression of RUNX1 with p50 further enhanced the NF-κB luciferase activity. Importantly, treatment with the RUNX1 inhibitor, Ro 5-3335, protected mice from LPS-induced endotoxic shock and substantially reduced the IL-6 levels. These findings suggest that RUNX1 may be a new potential target for resolving TLR4-associated uncontrolled inflammation and preventing sepsis.

Background: Sepsis is a high-mortality disease without effective therapeutic options. The hyperactivation of the monocyte-macrophage system, especially M1 macrophages, triggers the onset of septic shock. Gentiopicroside (GENT), the main active component in the traditional Chinese medicinal herb Radix Gentianae, has been shown to have anti-inflammatory properties. Nevertheless, this anti-inflammatory effect has not been fully elucidated.Methods: In vitro, we stimulated primary bone marrow-derived macrophages (BMMs) or peritoneal elucidated macrophages (PEMs) by lipopolysaccharide (LPS) and interferon (IFN)-γ and pre-treated with GENT and we tested the cytokines such as interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF) α production by enzyme linked immunosorbent assay (ELISA) or real-time quantitative PCR (qPCR). Further, we determined the NF-κB-mediated inflammatory pathway such as IKKα/β and p65 phosphorylation by Western blot. Then we detected the p65 nuclear localization by immunofluorescent staining. Moreover, NF-κB inhibitor and p65-targeted siRNAs were further used to validate the anti-inflammatory mechanism of GENT. In vivo, GENT (50 mg/kg) was administered intragastrically before and after LPS (40 mg/kg) injection. The death time were recorded and the serum levels of IL-1β, IL-6 and TNFα were tested by ELISA, and the IL-1β, IL-6 and TNFα mRNA expression in the lung were test by qPCR and the M1 infiltration in the lung were determined by F4/80 and INOS immunofluorescent staining Results: In vitro, we observed that GENT reduced the inflammatory cytokine production of BMMs stimulated by (LPS)/IFN-γ and ameliorated the phosphorylation of IKKα/β and p65, the degradation of IκBα, and the translocation of p65 into the nucleus. We did not find GENT has any effect on MAPK signaling under LPS/IFN-γ stimulation. NF-κB inhibitor and p65 siRNAs eliminated the inhibition effect of GENT. In vivo, we observed GENT prevented mice from dying in the LPS-induced shock model and decreased the serum levels of IL-1β and IL-6, the mRNA expression of IL-1β, IL-6 and TNFα in lung tissue, and the amount of M1 macrophage infiltration in the lung.Conclusions: GENT prevented LPS/IFN-γ-induced inflammatory cytokine production by macrophages through the NF-κB signaling pathway in vitro and protected against the endotoxin shock induced by LPS in vivo.

Alveolar macrophages (AMs) play critical roles in maintaining lung homeostasis and orchestrating the immune responses. Although the essential factors known for AM development have been identified, currently an optimal in vitro culture system that can be used for studying the development and functions of AMs is still lacking. In this study, we report the development of an optimized culture system for generating AM-like cells from adult mouse bone marrow and fetal liver cells on in vitro culture in the presence of a combination of GM-CSF, TGF-β, and peroxisome proliferator–activated receptor γ (PPAR-γ) agonist rosiglitazone. These AM-like cells expressed typical AM surface markers sialic acid–binding Ig-like lectin-F (Siglec-F), CD11c, and F4/80, and AM-specific genes, including carbonic anhydrase 4 (Car4), placenta-expressed transcript 1 (Plet1), eosinophil-associated RNase A family member 1 (Ear1), cell death–inducing DNA fragmentation factor A–like effector c (Cidec), and cytokeratin 19 (Krt19). Similar to primary AMs, the AM-like cells expressed alternative macrophage activation signature genes and self-renewal genes. Moreover, this culture system could be used for expansion of bronchoalveolar lavage fluid–derived AMs in vitro. The AM-like cells generated from bone marrow resembled the expanded bronchoalveolar lavage fluid–derived AMs in inflammatory responses and phagocytic activity. More importantly, these AM-like cells could be obtained in sufficient numbers that allowed genetic manipulation and functional analysis in vitro. Taken together, we provide a powerful tool for studying the biology of AMs.

SummaryPodocytes, the main target of immune complex, participate actively in the development of glomerular injury as immune cells. Dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) is an innate immune molecular that has an immune recognition function, and is involved in mediation of cell adhesion and immunoregulation. Here we explored the expression of DC-SIGN on podocytes and its role in immune and inflammatory responses in lupus nephritis (LN). Expression of DC-SIGN and immunoglobulin (Ig)G1 was observed in glomeruli of LN patients. DC-SIGN was co-expressed with nephrin on podocytes. Accompanied by increased proteinuria of LN mice, DC-SIGN and IgG1 expressions were observed in the glomeruli from 20 weeks, and the renal function deteriorated up to 24 weeks. Mice with anti-DC-SIGN antibody showed reduced proteinuria and remission of renal function. After the podocytes were stimulated by serum of LN mice in vitro, the expression of DC-SIGN, major histocompatibility complex (MHC) class II and CD80 was up-regulated, stimulation of T cell proliferation was enhanced and the interferon (IFN)-g/interleukin (IL)-4 ratio increased. However, anti-DC-SIGN antibody treatment reversed these events. These results suggested that podocytes in LN can exert DC-like function through their expression of DC-SIGN, which may be involved in immune and inflammatory responses of renal tissues. However, blockage of DC-SIGN can inhibit immune functions of podocytes, which may have preventive and therapeutic effects.