Microarray Analysis of mRNA and MicroRNA Expression Profile Reveals the Role of β -Sitosterol-D-glucoside in the Proliferation of Neural Stem Cell

Phytosterol and phytostanol-mediated epigenetic changes in cancer and other non-communicable diseases: a systematic review

Phytosterols/phytostanols are bioactive compounds found in vegetable oils, nuts and seeds and added to a range of commercial food products. Consumption of phytosterols/phytostanols reduces levels of circulating LDL-cholesterol, a causative biomarker of CVD, and is linked to a reduced risk of some cancers. Individuals who consume phytosterols/phytostanols in their diet may do so for many years as part of a non-pharmacological route to lower cholesterol or as part of a healthy diet. However, the impact of long term or high intakes of dietary phytosterols/phytostanols has not been on whole-body epigenetic changes before. The aim of this systematic review was to identify all publications that have evaluated changes to epigenetic mechanisms (post-translation modification of histones, DNA methylation and miRNA expression) in response to phytosterols/phytostanols. A systematic search was performed that returned 226 records, of which eleven were eligible for full-text analysis. Multiple phytosterols were found to inhibit expression of histone deacetylase (HDAC) enzymes and were also predicted to directly bind and impair HDAC activity. Phytosterols were found to inhibit the expression and activity of DNA methyl transferase enzyme 1 and reverse cancer-associated gene silencing. Finally, phytosterols have been shown to regulate over 200 miRNA, although only five of these were reported in multiple publications. Five tissue types (breast, prostate, macrophage, aortic epithelia and lung) were represented across the studies, and although phytosterols/phytostanols alter the molecular mechanisms of epigenetic inheritance in these mammalian cells, studies exploring meiotic or transgenerational inheritance were not found.

Western Pacific ALS-PDC: Evidence implicating cycad genotoxins

Amyotrophic Lateral Sclerosis and Parkinsonism-Dementia Complex (ALS-PDC) is a disappearing neurodegenerative disorder of apparent environmental origin formerly hyperendemic among Chamorros of Guam-USA, Japanese residents of the Kii Peninsula, Honshu Island, Japan and Auyu-Jakai linguistic groups of Papua-Indonesia on the island of New Guinea. The most plausible etiology is exposure to genotoxins in seed of neurotoxic cycad plants formerly used for food and/or medicine. Primary suspicion falls on methylazoxymethanol (MAM), the aglycone of cycasin and on the non-protein amino acid β-N-methylamino-L-alanine, both of which are metabolized to formaldehyde. Human and animal studies suggest: (a) exposures occurred early in life and sometimes during late fetal brain development, (b) clinical expression of neurodegenerative disease appeared years or decades later, and (c) pathological changes in various tissues indicate the disease was not confined to the CNS. Experimental evidence points to toxic molecular mechanisms involving DNA damage, epigenetic changes, transcriptional mutagenesis, neuronal cell-cycle reactivation and perturbation of the ubiquitin-proteasome system that led to polyproteinopathy and culminated in neuronal degeneration. Lessons learned from research on ALS-PDC include: (a) familial disease may reflect common toxic exposures across generations, (b) primary disease prevention follows cessation of exposure to culpable environmental triggers; and (c) disease latency provides a prolonged period during which to intervene therapeutically. Exposure to genotoxic chemicals ("slow toxins") in the early stages of life should be considered in the search for the etiology of ALS-PDC-related neurodegenerative disorders, including sporadic forms of ALS, progressive supranuclear palsy and Alzheimer's disease.

Lentivirus-mediated microRNA-26a-modified neural stem cells improve brain injury in rats with cerebral palsy

This study is launched to investigate the effect of lentivirus-mediated microRNA-26a (miR-26a)-modified neural stem cells (NSCs) in brain injury in rats with cerebral palsy (CP). The successfully constructed miR-26a lentivirus expression vector and empty vector virus were used to modify NSCs. The model of CP with ischemia and anoxia was established in rats. NSCs and miR-26a-NSCs were stereoscopically injected into the cerebral cortex of the modeled rats, respectively. The survival and migration of NSCs infected with recombinant lentivirus expressing green fluorescence in vivo was observed under a light microscope. The neurobehavioral functions, morphology, and ultrastructure of cerebral cortex and hippocampus, apoptosis of brain cells, expression of apoptosis-related protein caspase-3 and Bax, together with the expression of the glial fibrillary acidic protein (GFAP) in cerebral cortex and hippocampus were determined. Expression of miR-26a in NSCs infected with plVTHM-miR-26a increased significantly. After NSCs transplantation, the neurobehavioral status of CP rats was improved, the degree of brain pathological injury was alleviated, the apoptotic index of cells in cerebral cortex and hippocampus and the expression of the apoptotic protein (caspase-3 and Bax) were decreased, the expression of GFAP were significantly decreased. After miR-26a-NSCs transplantation, these aforementioned results further improved or decreased. Our study suggests that miR-26a-modified NSCs mediated by lentivirus can improve brain injury, inhibit apoptosis of brain cells and activation of astrocytes in CP rats.

Alyssum homolocarpum seed oil (AHSO), containing natural alpha linolenic acid, stearic acid, myristic acid and β-sitosterol, increases proliferation and differentiation of neural stem cells in vitro

Background

Embryonic neural stem cells (eNSCs) are immature precursors of the central nervous system (CNS), with self-renewal and multipotential differentiation capacities. These are regulated by endogenous and exogenous factors such as alpha-linolenic acid (ALA), a plant-based essential omega-3 polyunsaturated fatty acid.

Methods

In this study, we investigated the effects of various concentrations of Alyssum homolocarpum seed oil (AHSO), containing natural ALA, stearic acid (SA), myristic acid (MA), and β-sitosterol, on proliferation and differentiation of eNSCs, in comparison to controls and to synthetic pure ALA.

Results

Treatment with natural AHSO (25 to 75 μM), similar to synthetic ALA, caused a significant ~ 2-fold increase in eNCSs viability, in comparison to controls. To confirm this proliferative activity, treatment of NSCs with 50 or 75 μM AHSO resulted in a significant increase in mRNA levels of notch1, hes-1 and Ki-67and NICD protein expression, in comparison to controls. Moreover, AHSO administration significantly increased the differentiation of eNSCs toward astrocytes (GFAP+) and oligodendrocytes (MBP+) in a dose dependent manner and was more potent than ALA, at similar concentrations, in comparison to controls. Indeed, only high concentrations of 100 μM AHSO, but not ALA, caused a significant increase in the frequency of neurons (β-III Tubulin+).

Conclusion

Our data demonstrated that AHSO, a rich source of ALA containing also other beneficial fatty acids, increased the proliferation and stimulated the differentiation of eNSCs. We suggest that AHSO’s effects are caused by β-sitosterol, SA and MA, present within this oil. AHSO could be used in diet to prevent neurodevelopmental syndromes, cognitive decline during aging, and various psychiatric disorders.

MicroRNA-765 regulates neural stem cell proliferation and differentiation by modulating Hes1 expression

Neural stem cells (NSCs) are multipotent, self-renewing and undifferentiated cells that have the ability to differentiate to both glial and neuronal lineages. miRNAs act a key role in regulating neuronal fate and self-renewal of NSCs. In this study, we found that ectopic expression of miR-765 promoted NSCs proliferation. Moreover, miR-765 overexpression increased the ki-67 and β-tubulin-III expression inNSCs. Overexpression of miR-765 inhibited the expression of GFAP in NSCs. Furthermore, Hes1 was identified as a direct target gene of miR-765 in NSCs. Overexpression of Hes1 decreased miR-765-induced proliferation of NSCs and inhibited NSCs differentiation to neurons in miR-765-treated NSCs. These results demonstrated that miR-765 acted a crucial role in NSCs differentiation and proliferation by inhibiting Hes1 expression.

Tangeretin enhances radiosensitivity and inhibits the radiation-induced epithelial-mesenchymal transition of gastric cancer cells

Irradiation has been reported to increase radioresistance and epithelial-mesenchymal transition (EMT) in gastric cancer (GC) cells. The Notch pathway is critically implicated in cancer EMT and radioresistance. In the present study, we investigated the use of a Notch-1 inhibiting compound as a novel therapeutic candidate to regulate radiation-induced EMT in GC cells. According to previous screening, tangeretin, a polymethoxylated flavonoid from citrus fruits was selected as a Notch-1 inhibitor. Tangeretin enhanced the radiosensitivity of GC cells as demonstrated by MTT and colony formation assays. Tangeretin also attenuated radiation-induced EMT, invasion and migration in GC cells, accompanied by a decrease in Notch-1, Jagged1/2, Hey-1 and Hes-1 expressions. Tangeretin triggered the upregulation of miR-410, a tumor-suppressive microRNA. Furthermore, re-expression of miR-410 prevented radiation-induced EMT and cell invasion. An in vivo tumor xenograft model confirmed the antimetastasis effect of tangeretin as we observed in vitro. In nude mice, tumor size was considerably diminished by radiation plus tangeretin co-treatment. Tangeretin almost completely inhibited lung metastasis induced by irradiation. Tangeretin may be a novel antimetastatic agent for radiotherapy.