Coffee and caffeine potentiate the antiamyloidogenic activity of melatonin via inhibition of Aß oligomerization and modulation of the Tau-mediated pathway in N2a/APP cells.

There is an increasing prevalence of Alzheimer's disease (AD), which has become a public health issue. However, the underlying mechanisms for the pathogenesis of AD are not fully understood, and the current therapeutic drugs cannot produce acceptable efficacy in AD patients. Previous animal studies have shown that coffee (Coff), caffeine (Caff), and melatonin (Mel) have beneficial effects on AD. Disturbed circadian rhythms are observed in AD, and chronotherapy has shown promising effects on AD. In this study, we examined whether a combination of Coff or Caff plus Mel produced a synergistic/additive effect on amyloid-ß (Aß) generation in Neuro-2a (N2a)/amyloid precursor protein (APP) cells and the possible mechanisms involved. Cells were treated with Coff or Caff, with or without combined Mel, with three different chronological regimens. In regimen 1, cells were treated with Coff or Caff for 12 hours in the day, followed by Mel for 12 hours in the night. For regimen 2, cells were treated with Coff or Caff plus Mel for 24 hours, from 7 am to 7 am the next day. In regimen 3, cells were treated with Coff or Caff plus Mel with regimen 1 or 2 for 5 consecutive days. The extracellular Aß40/42 and Aß oligomer levels were determined using enzyme-linked immunosorbent assay (ELISA) kits. The expression and/or phosphorylation levels of glycogen synthase kinase 3ß (GSK3ß), Erk1/2, PI3K, Akt, Tau, Wnt3α, ß-catenin, and Nrf2 were detected by Western blot assay. The results showed that regimen 1 produced an additive antiamyloidogenic effect with significantly reduced extracellular levels of Aß40/42 and Aß42 oligomers. Regimen 2 did not result in remarkable effects, and regimen 3 showed a less antiamyloidogenic effect compared to regimen 1. Coff or Caff, plus Mel reduced oxidative stress in N2a/APP cells via the Nrf2 pathway. Coff or Caff, plus Mel inhibited GSK3ß, Akt, PI3K p55, and Tau phosphorylation but enhanced PI3K p85 and Erk1/2 phosphorylation in N2a/APP cells. Coff or Caff, plus Mel downregulated Wnt3α expression but upregulated ß-catenin. However, Coff or Caff plus Mel did not significantly alter the production of T helper cell (Th)1-related interleukin (IL)-12 and interferon (IFN)-γ and Th2-related IL-4 and IL-10 in N2a/APP cells. The autophagy of cells was not affected by the combinations. Taken together, combination of Caff or Coff, before treatment with Mel elicits an additive antiamyloidogenic effects in N2a/APP cells, probably through inhibition of Aß oligomerization and modulation of the Akt/GSK3ß/Tau signaling pathway.

Immune mechanism and clinical significance of macrophage to medullary hematopoietic injury of immune-related hematocytopenia patients.

BACKGROUND: Immune-related hematocytopenia (IRH) is considered to be related with the production of autoantibody, as well as the activation of humoral immunity which is stimulated by B lymphocyte. This study aimed to observe the levels of various cytokines in the blood serum and the in situ active state of macrophage (Mφ) in the medullary hematopoietic microenvironment of IRH patients, and to probe into the immune mechanism and clinical significance of Mφ in hematopoietic cell injury. METHODS: ELISA is used to detect the IL-4, IL-6, IL-12, IL-17, and IFN-γ levels in the peripheral blood serum of 376 patients in pre- and post-therapy. Cytochemistry and cell immunochemistry methods are used to observe the peroxidase (POX), nonspecific esterase (NSE), hemosiderin granules, and HLA-DR activity of Mφ in the bone marrow of patients. Immunofluorescence is used to observe the expression of hemocyte antihuman globulin IgG antibody, lymphocytes CD4 molecule, Mφ membrane FcγIIreceptor (FcγIIR), mannitose receptor (MR), IFN-γ, ICAM-1, IL-12, and IL-17A and the formation mechanism of antibody-dependent cell-mediated cytotoxicity (ADCC) hematopoietic cell islands (HI) in the medullary hematopoietic microenvironment of patients. Glucocorticoid is used for treatment on the basis of anti-infection therapy, and gamma globulin stoss therapy is used for the appearance of ADCC-type HI or serious Mφ bloodthirsty phenomenon; if necessary, association of Cyclosporine A (CsA) should be used and chalybeate should be supplemented. RESULTS: In the patient group, the levels of IL-4, IL-6, IL-12, IL-17, and IFN-γ were increased. After treatment, the cytokine levels gradually became normal. The activated Mφ in the marrow highly expressed NSE and POX, and Mφ swallowed more hemosiderin particles, but the iron in the cytoplasm of immature erythrocytes decreased. The activated Mφ expressed HLA-DR, MR, ICAM-1, IFN-γ, and IL-12. For patients with humoral immunity activation and bacterial infection, Mφ weakly expressed IL-17A but highly expressed FcγIIR, and the phenomenon that ADCC-type HI broke pathological blood corpuscles often occurred; for the cellular immune activation along with virus infection, the white blood count (WBC) significantly reduced, Mφ weakly expressed FcγIIR, secretory highly expressed IL-17A, and the phenomena that Mφ adhered to, captured and swallowed blood cell often occurred. After four weeks of anti-infective and immunosuppressive therapy, nuclear apoptosis of Mφ occurred in the bone marrow of patients, HI and bloodthirsty phenomenon disappeared, and the peripheral blood picture started to improve. CONCLUSIONS: Mφ is an important antigen presenting cell in the IRH marrow for hematopoiesis destruction and an immune effector cell of hematopoietic injury; infection can promote the activation of Mφ, upregulate the impression of immune molecule and receptors, form ADCC HI, aggravate hematopoietic injury, and accelerate the destruction on hematopoietic cell.