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Pleckstrin homology domain leucine-rich repeat protein phosphatase 2 (PHLPP2) has been known to exert tumor suppressive activity for long without much knowledge about its regulation and implications. Protein kinase B (Akt), Protein kinase C (PKC) and Ribosomal protein S6 Kinase (S6K) are known downtargets of PHLPP2, regulating a plethora of life processes viz. cell growth, survival and evasion from apoptosis. Present study decoded the crucial role of PHLPP2 in inducing apoptosis by its interaction with the newly found binding partner Mammalian sterile 20-like kinase 1 (Mst1) in berberine (BBR)-treated human hepatoma cells. HepG2 cells were exposed to (50 μM, 100 μM) berberine for different time intervals (18 h, 24 h). The results showed enhanced expression of PHLPP2 at transcriptional (2.13 fold, P  < 0.01) and translational level (4 fold, P  < 0.001), but not of PHLPP1, in berberine-treated HepG2 cells. Elevated expression of PHLPP2 was reported to inactivate Akt by dephosphorylating it on Ser473 ( P  < 0.001). As Akt is known to inhibit apoptotic effect of Mst1, we found that PHLPP2 mediated inactivation of Akt releases its repression from Mst1 leading to heightened phosphorylation of Mst1 on its activating site Thr183 (1.5 fold, P  < 0.001). Consequently, coordination between PHLPP2, Akt and Mst1 stimulated downstream targets c-jun N-terminal kinase (JNK), Bim and Bak which are direct activators of pro-apoptotic proteins leading to cell death. Further, PHLPP2/Mst1 knock-down efficiently curtailed anti-proliferative effect of berberine by restoring the basal level of downstream anti-apoptotic proteins. In addition, pre-treatment of NAC (5 mM) showed that ROS generation was a primitive event to initiate activation of stress kinases. Thus, our findings suggest that PHLPP2, Akt and Mst1 constitute an autoinhibitory triangle which may be partly responsible for antiproliferative effect of berberine. [ABSTRACT FROM AUTHOR]

Carcinogenesis has a multifactorial etiology, and the underlying molecular pathogenesis is still not entirely understood, especially for eye cancers. Primary malignant intraocular neoplasms are relatively rare, but delayed detection and inappropriate management contribute to poor outcomes. Conventional treatment, such as orbital exenteration, chemotherapy, or radiotherapy, alone results in high mortality for many of these malignancies. Recent sequential multimodal therapy with a combination of high-dose chemotherapy, followed by appropriate surgery, radiotherapy, and additional adjuvant chemotherapy has helped dramatically improve management. Transcription factors are proteins that regulate gene expression by modulating the synthesis of mRNA. Since transcription is a dominant control point in the production of many proteins, transcription factors represent key regulators for numerous cellular functions, including proliferation, differentiation, and apoptosis, making them compelling targets for drug development. Natural compounds have been studied for their potential to be potent yet safe chemotherapeutic drugs. Since the ancient times, plant-derived bioactive molecules have been used to treat dreadful diseases like cancer, and several refined pharmaceutics have been developed from these compounds. Understanding targeting mechanisms of oncogenic transcription factors by natural products can add to our oncologic management toolbox. This review summarizes the current findings of natural products in targeting specific oncogenic transcription factors in various types of eye cancer. [ABSTRACT FROM AUTHOR]

The traditional Japanese herbal medicine hangeshashinto (HST) has beneficial effects for the treatment of oral ulcerative mucositis (OUM) in cancer patients. However, the ingredient-based mechanism that underlies its pain-relieving activity remains unknown. In the present study, to clarify the analgesic mechanism of HST on OUM-induced pain, we investigated putative HST ingredients showing antagonistic effects on Na + channels in vitro and in vivo. A screen of 21 major ingredients using automated patch-clamp recordings in channel-expressing cells showed that [6]-gingerol and [6]-shogaol, two components of a Processed Ginger extract, considerably inhibited voltage-activated Na + currents. These two ingredients inhibited the stimulant-induced release of substance P and action potential generation in cultured rat sensory neurons. A submucosal injection of a mixture of [6]-gingerol and [6]-shogaol increased the mechanical withdrawal threshold in healthy rats. In a rat OUM model, OUM-induced mechanical pain was alleviated 30 min after the swab application of HST despite the absence of anti-bacterial and anti-inflammatory actions in the OUM area. A swab application of a mixture of [6]-gingerol and [6]-shogaol induced sufficient analgesia of OUM-induced mechanical or spontaneous pain when co-applied with a Ginseng extract containing abundant saponin. The Ginseng extract demonstrated an acceleration of substance permeability into the oral ulcer tissue without an analgesic effect. These findings suggest that Na + channel blockage by gingerol/shogaol plays an essential role in HST-associated analgesia of OUM-induced pain. This pharmacological mechanism provides scientific evidence supporting the use of this herbal medicine in patients suffering from OUM-induced pain. [ABSTRACT FROM AUTHOR]

Berberine (BBR) exerts powerful renoprotective effects on diabetic nephropathy (DN), but the underlying mechanisms remain unclear. We previously demonstrated that activation of the G protein-coupled bile acid receptor TGR5 ameliorates diabetic nephropathy by inhibiting the activation of the sphingosine 1-phosphate (S1P)/sphingosine 1-phosphate receptor 2 (S1P2) signaling pathway. In this study, we explored the role of TGR5 in the BBR-induced downregulation of sphingosine 1-phosphate receptor 2 (S1P2)/mitogen-activated protein kinase (MAPK)-mediated fibrosis in glomerular mesangial cells (GMCs). Results showed that, BBR suppressed the expression of FN, ICAM-1, and TGF-β1 in high-glucose cultures of GMCs, and the phosphorylation level of c-Jun/c-Fos was downregulated. The high glucose lowered TGR5 expression in a time-dependent manner; this effect was reversed by BBR in a dose-dependent manner. The TGR5 agonist INT-777 decreased the high glucose-induced FN, ICAM-1, and TGF-β1 protein contents. In addition, TGR5 siRNA blocked S1P2 degradation by BBR. And MAPK signaling, which plays important regulatory roles in the pathological progression of DN, was activated by TGR5 siRNA. Apart from this, MAPK signaling as well as FN, ICAM-1, and TGF-β1 suppressed by BBR under high glucose conditions were limited by TGR5 depletion. Thus, BBR decreases FN, ICAM-1, and TGF-β1 levels under high glucose conditions in GMCs possibly by activating TGR5 and inhibiting S1P2/MAPK signaling. [ABSTRACT FROM AUTHOR]

Dyslipidemia and hyperglycemia are associated with an increased risk of ischemic cardiovascular disease. Positive effects of a nutraceutical combination comprising red yeast rice, berberine, policosanol, astaxanthin, coenzyme Q 10 and folic acid (NComb) on plasma lipid and glucose levels have been reported in some but not all clinical trials. To address this inconsistency, we tried to estimate the size of lipid- and glucose-lowering effects of NComb through a systematic review and meta -analysis of randomized controlled trials. A systematic literature search in PubMed-Medline, SCOPUS and Google Scholar databases was conducted to identify randomized controlled trials investigating the effects of NComb on plasma lipids and glucose levels. Inverse variance-weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated for net changes in lipid and glucose levels using a random-effects model. Random-effects meta -regression was performed to assess the effect of putative confounders on plasma lipid and glucose levels. Fourteen trials (1670 subjects in the NComb arm and 1489 subjects in the control arm) met the eligibility criteria for lipid analysis and 10 trials (1014 subjects in the NComb arm and 962 subjects in the control arm) for glucose analysis. Overall, WMDs were significant for the impact of NComb supplementation on plasma levels of total cholesterol (−26.15 mg/dL, p < 0.001), LDL-cholesterol (−23.85 mg/dL, p < 0.001), HDL-cholesterol (2.53 mg/dL, p < 0.001), triglycerides (−13.83 mg/dL, p < 0.001) and glucose (−2.59 mg/dL, p = 0.010). NComb-induced amelioration of lipid profile was not affected by duration of supplementation nor by baseline lipid levels; conversely, a greater glucose-lowering effect of NComb was found with higher baseline glucose levels and longer durations of supplementation. In conclusion, the present results suggest that NComb supplementation is associated with improvement of lipid and glucose profile. Short-term beneficial effects of NComb supplementation appear to be maintained in the long term. [ABSTRACT FROM AUTHOR]

Non-alcoholic fatty liver disease (NAFLD) has reached an epidemic level globally, which is recognized to form non-alcoholic steatohepatitis (NASH) by the “two-hit” model, including oxidative stress and inflammation. AMP-activated protein kinase (AMPK) has long been regarded as a key regulator of energy metabolism, which is recognized as a critical target for NAFLD treatment. Here we introduce a natural product, demethyleneberberine (DMB), which potentially ameliorated NAFLD by activating AMPK pathways. Our study showed that the intraperitoneal injection of DMB (20 or 40 mg/kg body weight) decreased hepatic lipid accumulation in methionine and choline deficient (MCD) high-fat diet feeding mice and db/db mice. The further investigation demonstrated that DMB activated AMPK by increasing its phosphorylation in vitro and in vivo . Accompanied with AMPK activation, the expression of lipogenic genes were significantly reduced while genes responsible for the fatty acid β-oxidation were restored in DMB-treated NAFLD mice. In addition, the remarkable oxidative damage and inflammation induced by NAFLD were both attenuated by DMB treatment, which is reflected by decreased lipid oxidative product, malonaldehyde (MDA) and inflammatory factors, tumor necrosis factor α (TNFα) and interleukin 1β (IL-1β). Based on all above, DMB could serve as a novel AMPK activator for treating NAFLD and preventing the pathologic progression from NAFLD to NASH by inhibiting the oxidative stress and inflammation. [ABSTRACT FROM AUTHOR]

Post-translational modifications i.e. phosphorylation and acetylation are pivotal requirements for proper functioning of eukaryotic proteins. The current study aimed to decode the impact of acetylation/deacetylation of non-histone targets i.e. FoxO1/3a and p53 of sirtuins (NAD + dependent enzymes with lysine deacetylase activity) in berberine treated human hepatoma cells. Berberine (100 μM) inhibited sirtuins significantly ( P < 0.05) at transcriptional level as well as at translational level. Combination of nicotinamide (sirtuin inhibitor) with berberine potentiated sirtuins inhibition and increased the expression of FoxO1/3a and phosphorylation of p53 tumor suppressor protein. As sirtuins deacetylate non-histone targets including FoxO1/3a and p53, berberine increased the acetylation load of FoxO1/3a and p53 proteins. Acetylated FoxO and p53 proteins transcriptionally activate BH3-only proteins Bim and PUMA (3.89 and 3.87 fold respectively, P <0.001), which are known as direct activator of pro-apoptotic Bcl-2 family protein Bax that culminated into mitochondria mediated activation of apoptotic cascade. Bim/PUMA knock-down showed no changes in sirtuins' expression while cytotoxicity induced by berberine and nicotinamide was curtailed up to 28.3% ( P < 0.001) and it restored pro/anti apoptotic protein ratio in HepG2 cells. Sirtuins inhibition was accompanied by decline in NAD + /NADH ratio, ATP generation, enhanced ROS production and decreased mitochondrial membrane potential. TEM analysis confirmed mitochondrial deterioration and cell damage. SRT-1720 (1–10 μM), a SIRT-1 activator, when pre-treated with berberine (25 μM), reversed sirtuins expression comparable to control and significantly restored the cell viability ( P < 0.05). Thus, our findings suggest that berberine mediated sirtuins inhibition resulting into FoxO1/3a and p53 acetylation followed by BH3-only protein Bim/PUMA activation may in part be responsible for mitochondria-mediated apoptosis. [ABSTRACT FROM AUTHOR]

As a widely used anti-bacterial agent and a metabolic inhibitor as well as AMP-activated protein kinase (AMPK) activator, berberine (BBR) has been shown to cross the blood–brain barrier. Its efficacy has been investigated in various disease models of the central nervous system. Neurite outgrowth is critical for nervous system development and is a highly energy-dependent process regulated by AMPK-related pathways. In the present study, we aimed to investigate the effects of BBR on AMPK activation and neurite outgrowth in neurons. The neurite outgrowth of primary rat cortical neurons at different stages of polarization was monitored after exposure of BBR. Intracellular energy level, AMPK activation and polarity-related pathways were also inspected. The results showed that BBR suppressed neurite outgrowth and affected cytoskeleton stability in the early stages of neuronal polarization, which was mediated by lowered energy status and AMPK activation. Liver kinase B1 and PI3K–Akt–GSK3β signaling pathways were also involved. In addition, mitochondrial dysfunction and endoplasmic reticulum stress contributed to the lowered energy status induced by BBR. This study highlighted the knowledge of the complex activities of BBR in neurons and corroborated the significance of energy status during the neuronal polarization. [ABSTRACT FROM AUTHOR]