Identification of plicamycin, TG02, panobinostat, lestaurtinib, and GDC-0084 as promising compounds for the treatment of central nervous system infections caused by the free-living amebae Naegleria, Acanthamoeba and Balamuthia.

The free-living amebae Naegleria, Acanthamoeba, and Balamuthia cause rare but life-threatening infections. All three parasites can cause meningoencephalitis. Acanthamoeba can also cause chronic keratitis and both Balamuthia and Acanthamoeba can cause skin and systemic infections. There are minimal drug development pipelines for these pathogens despite a lack of available treatment regimens and high fatality rates. To identify anti-amebic drugs, we screened 159 compounds from a high-value repurposed library against trophozoites of the three amebae. Our efforts identified 38 compounds with activity against at least one ameba. Multiple drugs that bind the ATP-binding pocket of mTOR and PI3K are active, highlighting these compounds as important inhibitors of these parasites. Importantly, 24 active compounds have progressed at least to phase II clinical studies and overall 15 compounds were active against all three amebae. Based on central nervous system (CNS) penetration or exceptional potency against one amebic species, we identified sixteen priority compounds for the treatment of meningoencephalitis caused by these pathogens. The top five compounds are (i) plicamycin, active against all three free-living amebae and previously U.S. Food and Drug Administration (FDA) approved, (ii) TG02, active against all three amebae, (iii and iv) FDA-approved panobinostat and FDA orphan drug lestaurtinib, both highly potent against Naegleria, and (v) GDC-0084, a CNS penetrant mTOR inhibitor, active against at least two of the three amebae. These results set the stage for further investigation of these clinically advanced compounds for treatment of infections caused by the free-living amebae, including treatment of the highly fatal meningoencephalitis.

Melatonin enhances atherosclerotic plaque stability by inducing prolyl-4-hydroxylase α1 expression.

OBJECTIVE: Melatonin, an endogenous neurohormone secreted predominately by the pineal gland, has a variety of physiological functions. However, its protective role in atherosclerosis is not clear. In this study, we sought to investigate the potential effects of melatonin in modulating atherosclerotic plaque stability in apolipoprotein E knockout (ApoE) mice. METHOD AND RESULTS: Smooth muscle cells were treated with melatonin, which significantly increased mRNA and protein levels of a key intracellular enzyme essential for collagen maturation and secretion, prolyl-4-hydroxylase α1 (P4Hα1). Mechanistically, melatonin increased Akt phosphorylation and transcriptional activation of specificity protein 1 (Sp1), which bound with the P4Hα1 promoter and then induced P4Hα1 expression. Pretreatment with either Akt inhibitor LY294002 or Sp1 inhibitor mithramycin A (MTM) could inhibit melatonin-induced P4Hα1 expression. Finally, atherosclerotic lesions were induced by placing a perivascular collar on the right common carotid artery of ApoE mice, which were received with or without different doses of melatonin or MTM. High-dose melatonin enhanced atherosclerotic plaque stability in ApoE mice in vivo by inducing the expression of P4Hα1, which was reversed by MTM. CONCLUSION: We propose that melatonin supplementation may provide a novel and promising approach to atherosclerosis treatment.

The Antitumor Antibiotics Complex of Aureolic Acids from the Marine Sediment-associated Strain of Streptomyces sp. KNIM 9048.

A new antibiotic complex of six aureolic acids was isolated from the marine sediment-associated strain Streptomyces sp. KMM 9048. Four of the compounds (3-6) were found to be similar but not identical to the known chromomycins A2, A3, demethyl chromomycin A3 and A4. The two remaining.compounds; A2₋1 (1) and A3₋1 (2), were established as novel chromomycin analogs, which did not contain sugar B. Spectroscopic methods including ID and 2D NMR, and HRMS and MS/MS were applied for structure elucidation. Compounds 1-5 showed strong antimicrobial activity against Gram-positive indicatory bacteria Enterococcusfaecium, Staphylococcus aureus, S. epidernzidis, and Bacillus subtilis. Antitumor assay indicated that all tested compounds, in different manners, inhibited colony formation of RPMI-7951 and SK-Mel-28 cancer cells. This is the first study reporting the inhibitory effects of chromomycin analogs 1-5 on the colony formation of the investigated cancer cell lines. Compound 3, in a concentration of 5 nM, inhibited colony formation of RPMI-7951 and SK-Mel-28 cells by 82 % and 72 %, respectively. Our finding indicated that, of the compounds tested, 3 and 4 are promising anticancer and antimicrobial agents.

Beneficial effect of low-level laser therapy in acute lung injury after i-I/R is dependent on the secretion of IL-10 and independent of the TLR/MyD88 signaling.

The use of low-level laser for lung inflammation treatment has been evidenced in animal studies as well as clinical trials. The laser action mechanism seems to involve downregulation of neutrophil chemoattractants and transcription factors. Innate immune responses against microorganisms may be mediated by toll-like receptors (TLR). Intestinal ischemia and reperfusion (i-I/R) lead to bacterial product translocation, such as endotoxin, which consequently activates TLRs leading to intestinal and lung inflammation after gut trauma. Thus, the target of this study was to investigate the role of TLR activation in the laser (660 nm, 30 mW, 67.5 J/cm2, 0.375 mW/cm2, 5.4 J, 180 s, and spot size with 0.08 cm2) effect applied in contact with the skin on axillary lymph node in lung inflammation induced by i-I/R through a signaling adaptor protein known as myeloid differentiation factor 88 (MyD88). It is a quantitative, experimental, and laboratory research using the C57Bl/6 and MyD88-/- mice (n = 6 mice for experimental group). Statistical differences were evaluated by ANOVA and the Tukey-Kramer multiple comparisons test to determine differences among groups. In order to understand how the absence of MyD88 can interfere in the laser effect on lung inflammation, MyD88-/- mice were treated or not with laser and subjected to occlusion of the superior mesenteric artery (45 min) followed by intestinal reperfusion (4 h). In summary, the laser decreased the MPO activity and the lung vascular permeability, thickened the alveolar septa, reduced both the edema and the alveolar hemorrhage, as well as significantly decreased neutrophils infiltration in MyD88-deficient mice as well in wild-type mice. It noted a downregulation in chemokine IL-8 production as well as a cytokine IL-10 upregulation in these animals. The results also evidenced that in absence of IL-10, the laser effect is reversed. Based on these results, we suggest that the beneficial effect of laser in acute lung injury after i-I/R is dependent on the secretion of IL-10 and independent of the TLR/MyD88 signaling.

Coffee reduces SULT1E1 expression in human colon carcinoma Caco-2 cells.

Recent epidemiological studies have shown that moderate coffee consumption is associated with a lower risk of certain types of cancers, particularly colon cancer in postmenopausal women. To elucidate the molecular basis for the preventive action of coffee, we investigated the effect of coffee on estrogen sulfotransferase (SULT) because sulfation is the major pathway involved in the inactivation of estrogens. We found that coffee reduced SULT1E1 gene expression in human colon carcinoma Caco-2 cells. Treatment with 2.5% (v/v) coffee for 24 h resulted in a 60% reduction of the expression of the SULT1E1 gene in Caco-2 cells. Corresponding to reduced SULT1E1 gene expression, cytosolic estrogen SULT activity toward E(2) (20 nM) decreased by 25%. In addition, an accumulation of E(2) sulfates in the medium, which reflects cellular activity of estrogen SULT, decreased after the cells were treated with coffee. Major bioactive constituents in coffee such as caffeine, chlorogenic acid and caffeic acid did not show any effect. The inhibitory activity was extractable by using ethyl acetate. We also found that the inhibitory activity was produced by roasting the coffee beans. Mithramycin, an inhibitor of the transcription factor stimulating protein 1 (Sp1), was able to restore coffee-reduced SULT1E1 gene expression. Our data suggest that daily coffee consumption may reduce estrogen SULT activity, thereby enhancing estrogenic activity in the colon.

Mithramycin effects on calcium, phosphorus and parathyroid hormone in osseous Paget's disease.

Six patients with symptomatic osseous Paget's disease were treated with a four-day course of mithramycin (25 mug/kg/day). The effects of treatment on the plasma calcium, phosphorus, parathyroid hormone, and the urinary fractional clearance of calcium and phosphorus were studied. Mithramycin produced significant hypocalcemia and hypophosphatemia, and also significantly and simultaneously increased the plasma parathyroid hormone concentration. Despite the increase in parathyroid hormone, the hypocalemia persisted because of the probable blocking effect which mithramycin exerted on the osteoclasts. The physiological response of the kidney to the elevated plasma parathyroid hormone appeared to be well preserved, as evidenced by the decreased fractional excretion of calcium and the increased fractional excretion of phosphorus in the urine; however, the fall in the clearance of calcium could be the result of the decreased filtered load.