RESULTS: We show that miR-15a is increased in the plasma of diabetic patients, correlating with disease severity. miR-15 plays an important role in insulin production in pancreatic β-cells. By culturing rat pancreatic β-cells (INS-1) cells in high-glucose media, we identified a source of increased miR-15a in the blood as exosomes secreted by pancreatic β-cells. We postulate that miR-15a, produced in pancreatic β-cells, can enter the bloodstream and contribute to retinal injury. miR-15a overexpression in Müller cells can be induced by exposing Müller cells to exosomes derived from INS-1 cells under high-glucose conditions and results in oxidative stress by targeting Akt3, which leads to apoptotic cell death. The in vivo relevance of these findings is supported by results from high-fat diet and pancreatic β-cell-specific miR-15a-/- mice.
INNOVATION: This study highlights an important and underappreciated mechanism of remote cell-cell communication (exosomal transfer of miRNA) and its influence on the development of T2D complications.
CONCLUSION: Our findings suggest that circulating miR-15a contributes to the pathogenesis of diabetes and supports the concept that miRNAs released by one cell type can travel through the circulation and play a role in disease progression via their transfer to different cell types, inducing oxidative stress and cell injury. Antioxid. Redox Signal. 27, 913-930.
Materials and Methods: SF1 was produced by optimized methodology for bioassay-guided fractionation. Fourier transform infrared (FTIR) spectroscopy and liquid chromatography-mass spectrometry (LC-MS) were carried out to characterize the SF1. SF1 was screened for cytotoxicity activity toward HeLa, SiHa, and normal cells (NIH) cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. The anticancer mechanism of SF1 was evaluated toward SiHa cells, which showed highest cytotoxicity toward SF1 treatment. The mechanism includes cell cycle progression and protein expression, which was detected using specific antibody-conjugated fluorescent dye, p53-FITC, by flow cytometry.
Results: Major constituents of SF1 were alkaloids with amines as functional group. SF1 showed highest cytotoxic activity against SiHa (half-maximal inhibitory concentration [IC50] < 10 µg/mL) compared to HeLa cells. Cytoselectivity of SF1 was observed with no IC50 detected on normal NIH cells. On flow cytometry analysis, SF1 was able to induce apoptosis on SiHa cells by arresting cell cycle at G1/S and upregulation of p53 protein.
Conclusion: SF1 showed anticancer activity by inducing apoptosis through arrested G1/S cell cycle checkpoint-mediated mitochondrial pathway.
METHODS: Release of interleukin (IL)-1β and tumor necrosis factor (TNF)-α, and production of prostaglandin E2 (PGE2) were determined by using enzyme-linked immunosorbent assay (ELISA). Immunoblot technique was executed to determine the activation of MAPKs molecules, NF-κB, PI3K-Akt and cyclooxygenase-2 (COX-2) protein. Determination of pro-inflammatory cytokines and COX-2 relative gene expression levels was by performing the real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). A reversed-phase HPLC method was developed and validated to standardize the T. crispa extract and chemical profiling of its secondary metabolites was performed by LC-MS/MS.
RESULTS: Qualitative and quantitative analyses of chromatographic data indicated that syringin and magnoflorine were found as the major components of the extract. T. crispa-treatment prompted activation of NF-κB by enhancing IKKα/β and NF-κB (p65) phosphorylation, and degradation of IκBα. The extract upregulated COX-2 protein expression, release of pro-inflammatory mediators and MAPKs (ERK, p38 and JNK) phosphorylation as well as Akt dose-dependently. T. crispa extract also upregulated the upstream signaling adaptor molecules, toll-like receptor 4 (TLR4) and MyD88. T. crispa-treatment also upregulated the pro-inflammatory markers mRNA expression.
CONCLUSION: The results suggested that T. crispa extract stimulated the MyD88-dependent signaling pathways by upregulating the various immune inflammatory related parameters.
OBJECTIVES: We explored the possible preventive/therapeutic effects of orlistat (a medication prescribed for weight loss) on obesity-induced steroidogenesis and spermatogenesis decline.
MATERIALS AND METHODS: Twenty-four adult male Sprague Dawley rats weighing 250-300 g were randomized into four groups (n = 6/group), namely; normal control, high-fat diet, high-fat diet plus orlistat preventive group and high-fat diet plus orlistat treatment group. Orlistat (10 mg/kg/b.w./d suspended in distilled water) was either concurrently administered with high-fat diet for 12 weeks (high-fat diet plus orlistat preventive group) or administered from week 7-12 post- high-fat diet feeding (high-fat diet plus orlistat treatment group). Thereafter, serum, testes and epididymis were collected for analyses.
RESULTS: Obesity increased serum leptin and decreased adiponectin levels, decreased serum and intra-testicular levels of follicle stimulating hormone, luteinising hormone and testosterone, sperm count, motility, viability, normal morphology and epididymal antioxidants, but increased epididymal malondialdehyde level and sperm nDNA fragmentation. Testicular mRNA transcript levels of androgen receptor, luteinizing hormone receptor, steroidogenic acute regulatory protein, cytochrome P450 enzyme (CYP11A1), 3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase were significantly decreased in the testes of the high-fat diet group. Further, the levels of steroidogenic acute regulatory protein protein and enzymatic activities of CYP11A1, 3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase were also significantly decreased in the testes of the high-fat diet group. Treatment with orlistat significantly decreased leptin and increased adiponectin levels, improved sperm parameters, decreased sperm DNA fragmentation, increased the levels of steroidogenic hormones, proteins and associated genes in high-fat diet-induced obese male rats, with the preventive group (high-fat diet plus orlistat preventive group) having better results relative to the treatment group (high-fat diet plus orlistat treatment group).
DISCUSSION AND CONCLUSION: Orlistat attenuated impaired spermatogenesis and steroidogenesis decline by up-regulating steroidogenic genes. This may not be unconnected to its significant effect in lowering serum leptin levels, since the hormone is known to dampen fertility potential. Therefore, orlistat may improve fertility potential in overweight/obese men.