Combination of Evodiamine with Berberine Reveals a Regulatory Effect on the Phenotypic Transition of Colon Epithelial Cells Induced by CCD-18Co.

Objective Transdifferentiation exists between stromal cells or between stromal cells and cancer cells. Evodiamine and berberine are predominant pharmacological components of Zuojin pill, a prescription of Traditional Chinese Medicine, playing crucial functions in remolding of tumor microenvironment. This study aimed to explore the effect of combination of evodiamine with berberine (cBerEvo) on the phenotypic transition of colon epithelial cells induced by tumor-associated fibroblasts, as well as the involved mechanisms.Methods Human normal colon epithelial cell line HCoEpiC cells were treated with the prepared conditioned medium of CCD-18Co, a human colon myofibroblast line, to induce epithelial-mesenchymal transition. Phase contrast microscope was used to observe the morphological changes. Epithelial-mesenchymal transition markers including E-cadherin, vimentin and alpha-smooth muscle actin (α-SMA) were observed with immunofluorescence microscopy. Migration was assessed by wound healing assay. Western blotting was used to detect the expressions of E-cadherin, vimentin, α-SMA, Snail, ZEB1 and Smads. Results In contrast to the control, the tumor-associated fibroblasts-like CCD-18Co cells induced down-regulation of E-cadherin and up-regulation of vimentin, α-SMA, Snail and ZEB1 (P<0.05), and promoted migration of HCoEpiCs (P<0.05), with over expression of Smads including Smad2, p-Smad2, Smad3, p-Smad3 and Smad4 (P<0.05), which were abolished by a transforming growth factor-ß (TGF-ß) receptor inhibitor LY364947 and by cBerEvo in a concentration dependent manner. In addition, cBerEvo-inhibited ratios of p-Smad2/Smad2 and p-Smad3/Smad3 were also dose dependent.Conclusion The above results suggest that cBerEvo can regulate the differentiation of colon epithelial cells induced by CCD-18Co through suppressing activity of TGF-ß/Smads signaling pathway.

High dose zinc supplementation induces hippocampal zinc deficiency and memory impairment with inhibition of BDNF signaling.

Zinc ions highly concentrate in hippocampus and play a key role in modulating spatial learning and memory. At a time when dietary fortification and supplementation of zinc have increased the zinc consuming level especially in the youth, the toxicity of zinc overdose on brain function was underestimated. In the present study, weaning ICR mice were given water supplemented with 15 ppm Zn (low dose), 60 ppm Zn (high dose) or normal lab water for 3 months, the behavior and brain zinc homeostasis were tested. Mice fed high dose of zinc showed hippocampus-dependent memory impairment. Unexpectedly, zinc deficiency, but not zinc overload was observed in hippocampus, especially in the mossy fiber-CA3 pyramid synapse. The expression levels of learning and memory related receptors and synaptic proteins such as NMDA-NR2A, NR2B, AMPA-GluR1, PSD-93 and PSD-95 were significantly decreased in hippocampus, with significant loss of dendritic spines. In keeping with these findings, high dose intake of zinc resulted in decreased hippocampal BDNF level and TrkB neurotrophic signaling. At last, increasing the brain zinc level directly by brain zinc injection induced BDNF expression, which was reversed by zinc chelating in vivo. These results indicate that zinc plays an important role in hippocampus-dependent learning and memory and BDNF expression, high dose supplementation of zinc induces specific zinc deficiency in hippocampus, which further impair learning and memory due to decreased availability of synaptic zinc and BDNF deficit.

Synaptic released zinc promotes tau hyperphosphorylation by inhibition of protein phosphatase 2A (PP2A).

Hyperphosphorylated tau is the major component of neurofibrillary tangles in Alzheimer disease (AD), and the tangle distribution largely overlaps with zinc-containing glutamatergic neurons, suggesting that zinc released in synaptic terminals may play a role in tau phosphorylation. To explore this possibility, we treated cultured hippocampal slices or primary neurons with glutamate or Bic/4-AP to increase the synaptic activity with or without pretreatment of zinc chelators, and then detected the phosphorylation levels of tau. We found that glutamate or Bic/4-AP treatment caused tau hyperphosphorylation at multiple AD-related sites, including Ser-396, Ser-404, Thr-231, and Thr-205, while application of intracellular or extracellular zinc chelators, or blockade of zinc release by extracellular calcium omission almost abolished the synaptic activity-associated tau hyperphosphorylation. The zinc release and translocation of excitatory synapses in the hippocampus were detected, and zinc-induced tau hyperphosphorylation was also observed in cultured brain slices incubated with exogenously supplemented zinc. Tau hyperphosphorylation induced by synaptic activity was strongly associated with inactivation of protein phosphatase 2A (PP2A), and this inactivation can be reversed by pretreatment of zinc chelator. Together, these results suggest that synaptically released zinc promotes tau hyperphosphorylation through PP2A inhibition.