Melatonin induces Nrf2-HO-1 reprogramming and corrections in hepatic core clock oscillations in Non-alcoholic fatty liver disease.

Melatonin pleiotropically regulates physiological events and has a putative regulatory role in the circadian clock desynchrony-mediated Non-alcoholic fatty liver disease (NAFLD). In this study, we investigated perturbations in the hepatic circadian clock gene, and Nrf2-HO-1 oscillations in conditions of high-fat high fructose (HFHF) diet and/or jet lag (JL)-mediated NAFLD. Melatonin treatment (100 µM) to HepG2 cells led to an improvement in oscillatory pattern of clock genes (Clock, Bmal1, and Per) in oleic acid (OA)-induced circadian desynchrony, while Cry, Nrf2, and HO-1 remain oblivious of melatonin treatment that was also validated by circwave analysis. C57BL/6J mice subjected to HFHF and/or JL, and treated with melatonin showed an improvement in the profile of lipid regulatory genes (CPT-1, PPARa, and SREBP-1c), liver function (AST and ALT) and histomorphology of fatty liver. A detailed scrutiny revealed that hepatic mRNA and protein profiles of Bmal1 (at ZT6) and Clock (at ZT12) underwent corrective changes in oscillations, but moderate corrections were recorded in other components of clock genes (Per1, Per2, and Cry2). Melatonin induced changes in oscillations of anti-oxidant genes (Nrf2, HO-1, and Keap1) subtly contributed in the overall improvement in NAFLD recorded herein. Taken together, melatonin induced reprograming of hepatic core clock and Nrf2-HO-1 genes leads to an improvement in HFHF/JL-induced NAFLD.

HSP60 knockdown exerts differential response in endothelial cells and monocyte derived macrophages during atherogenic transformation.

Ectopic expression of HSP60 in vascular cells is known to activate auto-immune response that is critical to atherogenic initiation. However, the pathogenic relevance of the aberrant HSP60 upregulation in intracellular signaling pathways associated with atherogenic consequences in vascular cells remains unclear. The aim of the present study was to determine the role of endogenous HSP60 in atherogenic transformation of endothelial cells and macrophages. After generating primary evidence of oxidized low density lipoprotein (OxLDL) induced HSP60 upregulation in human umbilical vein endothelial cells (HUVEC), its physiological relevance in high fat high fructose (HFHF) induced early atherogenic remodelling was investigated in C57BL/6J mice. Prominent HSP60 expression was recorded in tunica intima and media of thoracic aorta that showed hypertrophy, lumen dilation, elastin fragmentation and collagen deposition. Further, HSP60 overexpression was found to be prerequisite for its surface localization and secretion in HUVEC. eNOS downregulation and MCP-1, VCAM-1 and ICAM-1 upregulation with subsequent macrophage accumulation provided compelling evidences on HFHF induced endothelial dysfunction and activation that were also observed in OxLDL treated- and HSP60 overexpressing-HUVEC. OxLDL induced concomitant reduction in NO production and monocyte adhesion were prevented by HSP60 knockdown, implying towards HSP60 mediated possible regulation of the said genes. OxLDL induced HSP60 upregulation and secretion was also recorded in THP-1 derived macrophages (TDMs). HSP60 knockdown in TDMs accounted for higher OxLDL accumulation that correlated with altered scavenger receptors (SR-A1, CD36 and SR-B1) expression further culminating in M1 polarization. Collectively, the results highlight HSP60 upregulation as a critical vascular alteration that exerts differential regulatory role in atherogenic transformation of endothelial cells and macrophages.

Surface modified PAMAM dendrimers with gallic acid inhibit, cell proliferation, cell migration and inflammatory response to augment apoptotic cell death in human colon carcinoma cells.

To overcome the obstacle of anti-cancer therapy significant attention has been drawn for improving drug delivery system. Since recent past, different approaches were applied using synthetic or natural derivatives for improving efficacy of anti-cancer drugs in cancer therapeutics. Gallic acid (GA) is a natural polyphenol, which exhibits a broad spectrum of biological activities, but its therapeutic application was limited due to poor bioavailability and toxicity. In the present study, we had conjugated the GA with PAMAM dendrimers and proposed the insights of molecular mechanism on inhibition of cell proliferation and programmed cell death through apoptotic pathway in human colon carcinoma cells. GA was chemically conjugated with 4.0 G PAMAM dendrimer at outer surface and characterized by different biophysical methods. We further examined its bioavailability, anti-cancer activity and explored the molecular mechanism of programmed cell death signaling in HCT116 cells. The results show that PAMAM-GA conjugate inhibits cell proliferation of different origin of cancer cells, improves cellular uptake of GA, inhibits colonogenic ability, restricts cancer cell migration by down regulating the expression of MMP-9, inhibits NF-kB activation and release of pro-inflammatory cytokines to manifest apoptotic cell death in HCT 116 cells rather than necrosis. On other hand, PAMAM-GA conjugate showed negligible cytotoxic response as compared to the free Gallic acid to the normal cells. In conclusion, findings of this study revealed that PAMAM-GA conjugate improves the bioavailability of GA and specificity towards cancer cellsto manifests apoptotic cell death. This indispensable approach may be beneficial for the revolution of anti-cancer therapy.Communicated by Ramaswamy H. Sarma.

Tyrosine kinase inhibitor AG490 inhibits the proliferation and migration and disrupts actin organization of cancer cells.

Metastasis, a multistep process, is a major cause of mortality in cancer patients. Thus, it is hoped that inhibition of metastasis at any step, such as proliferation, migration, or invasion, using small-molecule inhibitors will reduce this mortality. Recent study suggests that the Janus kinase/signal transducer and activator of transcription 3 signal transduction pathway is a central pathway that regulates tumor progression and metastasis and can be blocked using tyrosine kinase inhibitors. In this study we used a synthetic tyrosine kinase inhibitor, AG490, to block the constitutive activation of the Janus kinase/signal transducer and activator of transcription 3 pathway in A549 lung carcinoma and A375 melanoma cell lines. Our results show that AG490 at subtoxic doses can effectively suppress tumor cell proliferation by limiting the expression of cyclin D1. Furthermore, AG490 is seen to induce apoptosis, inhibit cellular migration by disrupting actin organization, and suppress matrix metalloproteinase 2 activity. Taken together, these data demonstrate that AG490 can exert antimetastatic activity by inhibiting cellular proliferation, invasion, and migration.