BackgroundMacrophages are tissue resident immune cells important for host defence and homeostasis. During diabetes, macrophages and other innate immune cells are known to have a pro-inflammatory phenotype, which is believed to contribute to the pathogenesis of various diabetic complications. However, diabetic patients are highly susceptible to bacterial infections, and often have impaired wound healing. The molecular mechanism underlying the paradox of macrophage function in diabetes is not fully understood. Recent evidence suggests that macrophage functions are governed by metabolic reprograming. Diabetes is a disorder that affects glucose metabolism; dysregulated macrophage function in diabetes may be related to alterations in their metabolic pathways. In this study, we seek to understand the effect of high glucose exposure on macrophage phenotype and functions.ResultsBone marrow cells were cultured in short or long term high glucose and normal glucose medium; the number and phenotype of bone marrow derived macrophages were not affected by long-term high glucose treatment. Short-term high glucose increased the expression of IL-1β. Long-term high glucose increased the expression of IL-1β and TNFα but reduced the expression of IL-12p40 and nitric oxide production in M1 macrophage. The treatment also increased Arg-1 and IL-10 expression in M2 macrophages. Phagocytosis and bactericidal activity was reduced in long-term high glucose treated macrophages and peritoneal macrophages from diabetic mice. Long-term high glucose treatment reduced macrophage glycolytic capacity and glycolytic reserve without affecting mitochondrial ATP production and oxidative respiration.ConclusionLong-term high glucose sensitizes macrophages to cytokine stimulation and reduces phagocytosis and nitric oxide production, which may be related to impaired glycolytic capacity.Electronic supplementary materialThe online version of this article (10.1186/s12865-018-0261-0) contains supplementary material, which is available to authorized users.

Although members of the p63 family of transcription factors are known for their role in the development and differentiation of epithelial surfaces, their function in cancer is less clear. Here, we show that depletion of the ⌬Np63␣ and ␤ isoforms, leaving only ⌬Np63␥, results in epithelial to mesenchymal transition (EMT) in the normal breast cell line MCF10A. EMT can be rescued by the expression of the ⌬Np63␣ isoform. We also show that ⌬Np63␥ expressed in a background where all the other ⌬Np63 are knocked down causes EMT with an increase in TGF␤-1, -2, and -3 and downstream effectors Smads2/3/4. In addition, a p63 binding site in intron 1 of TGF␤ was identified. Inhibition of the TGF␤ response with a specific inhibitor results in reversion of EMT in ⌬Np63␣-and ␤-depleted cells. In summary, we show that p63 is involved in inhibiting EMT and reduction of certain p63 isoforms may be important in the development of epithelial cancers.The transcription factor p63 is a member of the p53 gene family. At least six isoforms are expressed as a result of two alternative promoters giving rise to transactivating (TA) 2 isoforms, containing a transactivation domain at the amino terminus and ⌬N isoforms that lack this domain (1, 2). There are also 3Ј splicing events giving rise to ␣, ␤, and ␥ variants. All isoforms contain a DNA binding domain (DBD), but different p63 isoforms have different functional properties. TA variants can bind to p53-responsive elements to activate p53 target genes, and the ⌬N variants can act as dominant negative inhibitors of this transcriptional activity (1, 4). In addition, the ⌬Np63 isoforms, particularly ␥, have been shown to activate certain genes (5). p63 is essential for the development and differentiation of stratified squamous epithelium (5-7). Mice null for the p63 gene show a lack of stratified epithelium and epidermal appendages, as well as absence of lachrymal, salivary, and mammary glands (1, 8). The p63 gene has been implicated in cancer and tumor progression and can act as an oncogene (9, 10) or a tumor suppressor (11-13), depending on the cellular context. Knockdown of p63 has been shown to lead to a loss of cell adhesion, cellular arrest (14, 15), invasion, and metastasis (15), of which the latter are important steps in tumor progression.A process that has been significantly linked to tumor progression and metastasis in cancer is epithelial to mesenchymal transition (EMT;(16)(17)(18). EMT is the process in which immotile epithelial cells transition into motile fibroblastic-like cells. A hallmark event in EMT is the loss of E-cadherin that leads to the disassembly of tight junction complexes, along with rearrangement of the actin cytoskeleton (16,17). EMT is involved in normal embryogenesis and tissue morphogenesis, and in adults it is required for the maintenance of the epithelium, through wound healing and tissue repair (19). However, aberrant activation of EMT can cause cellular invasion and metastasis in cancer. A variety of specific growth and differentiation factors, such as Wnt...

The PC12 pheochromocytoma cell line responds to nerve growth factor (NGF) by exiting from the cell cycle and differentiating to induce extending neurites. Cyclin D1 is an important regulator of G1/S phase cell cycle progression, and it is known to play a role in myocyte differentiation in cultured cells. Herein, NGF induced cyclin D1 promoter, mRNA, and protein expression via the p21(RAS) pathway. Antisense- or small interfering RNA to cyclin D1 abolished NGF-mediated neurite outgrowth, demonstrating the essential role of cyclin D1 in NGF-mediated differentiation. Expression vectors encoding mutants of the Ras/mitogen-activated protein kinase pathway, and chemical inhibitors, demonstrated NGF induction of cyclin D1 involved cooperative interactions of extracellular signal-regulated kinase, p38, and phosphatidylinositol 3-kinase pathways downstream of p21(RAS). NGF induced the cyclin D1 promoter via Sp1, nuclear factor-kappaB, and cAMP-response element/activated transcription factor sites. NGF induction via Sp1 involved the formation of a Sp1/p50/p107 complex. Cyclin D1 induction by NGF governs differentiation and neurite outgrowth in PC12 cells.

The ErbB2 (Her2/neu epidermal growth receptor family) oncogene is overexpressed in 30% to 40% of human breast cancers. Cyclin D1 is the regulatory subunit of the holoenzyme that phosphorylates and inactivates the retinoblastoma (pRb) tumor suppressor and is an essential downstream target of ErbB2-induced tumor growth. Herein, we demonstrate that ErbB2 induces the activity of the Notch signaling pathway. ErbB2 induction of DNA synthesis, contact-independent growth, and mammosphere induction required Notch1. ErbB2-induced cyclin D1 and cyclin D1 expression was sufficient to induce Notch1 activity, and conversely, genetic deletion of Notch1 in mammary epithelial cells using floxed Notch (Notchfl/fl ) mice demonstrated that cyclin D1 is induced by Notch1. Genetic deletion of cyclin D1 or small interfering RNA (siRNA) to cyclin D1-reduced Notch1 activity and reintroduction of cyclin D1 into cyclin D1-deficient cells restored Notch1 activity through the inhibition of Numb, an endogenous inhibitor of Notch1 activity. Thus, cyclin D1 functions downstream as a genetic target of Notch1, amplifies Notch1 activity by repressing Numb, and identifies a novel pathway by which ErbB2 induces Notch1 activity via the induction of cyclin D1.