Modification of cysteine 457 in plakoglobin modulates the proliferation and migration of colorectal cancer cells by altering binding to E-cadherin/catenins

THBS1/CD47 Modulates the Interaction of γ-Catenin With E-Cadherin and Participates in Epithelial-Mesenchymal Transformation in Lipid Nephrotoxicity

Hyperlipidemia, an important risk factor for cardiovascular and end-stage renal diseases, often aggravates renal injury and compromises kidney function. Here, histological analysis of human kidney samples revealed that high lipid levels induced the development of renal fibrosis. To elucidate the mechanism underlying lipid nephrotoxicity, we used two types of mouse models (Apoe^−/− and C57BL/6 mice fed a 45 and 60% high-fat diet, respectively). Histological analysis of kidney tissues revealed high-lipid-induced renal fibrosis and inflammation; this was confirmed by examining fibrotic and inflammatory marker expression using Western blotting and real-time polymerase chain reaction. Oxidized low-density lipoprotein (OX-LDL) significantly induced the fibrotic response in HK-2 tubular epithelial cells. RNA-sequencing and Gene Ontology analysis of differentially expressed mRNAs in OX-LDL-treated HK-2 tubular epithelial cells and real-time PCR validation in Apoe^−/− mice showed that the expression of thrombospondin-1 (THBS1) in the high-fat group was significantly higher than that of the other top known genes, along with significant overexpression of its receptor CD47. THBS1 knockdown cells verified its relation to OX-LDL-induced fibrosis and inflammation. Liquid chromatography tandem mass spectrometry and STRING functional protein association network analyses predicted that THBS1/CD47 modulated the interaction between γ-catenin and E-cadherin and was involved in epithelial–mesenchymal transition, which was supported by immunoprecipitation and immunohistochemistry. CD47 downregulation following transfection with small-hairpin RNA in OX-LDL-treated tubular epithelial cells and treatment with anti-CD47 antibody restored the expression of E-cadherin and attenuated renal injury, fibrosis, and inflammatory response in OX-LDL-treated cells and in type 2 diabetes mellitus. These findings indicate that CD47 may serve as a potential therapeutic target in long-term lipid-induced kidney injury.

Sirtuin 7 promotes colorectal carcinoma proliferation and invasion through the inhibition of E-cadherin

Sirtuin 7 (Sirt7) is a member of the sirtuin protein family and is implicated in various carcinomas; however, the function of Sirt7 in colorectal carcinoma (CRC) remains unclear. The present study aimed to explore the biological function of Sirt7 in CRC tissues and cell lines, and to investigate the potential underlying mechanism by performing reverse transcription-quantitative polymerase chain reaction analyses, western blot analyses, luciferase reporter assays, cell proliferation and invasion assays. It was demonstrated that Sirt7 presented a higher expression in CRC tissues and cell lines compared with that in normal tissues and cells, and this higher expression was correlated with the tumor size, the tumor, node and metastasis stage and distant metastasis. Knockdown of Sirt7 repressed the proliferation ability of SW620 and HCT116 cells in vitro, while ectopic expression of Sirt7 increased the epithelial-mesenchymal transition and invasion in HT29 and SW480 cells. Notably, these functional effects of Sirt7 were exerted through the repression of E-cadherin. Thus, the data of the present study indicated a novel mechanistic role for Sirt7 as an oncogene in CRC malignancy, and Sirt7 may be a potential therapeutic target.

Early alterations of mitochondrial morphology in dopaminergic neurons from Parkinson's disease-like pathology and time-dependent neuroprotection with D2 receptor activation

Neuroprotection, to prevent vulnerable cell populations from dying, is perhaps the main strategy for treating Parkinson's disease (PD). Yet in clinical practice, therapy is introduced after the disease is well established and many neurons have already disappeared, while experimentally, treatment is typically added at the same time that PD pathology is instigated. This study uses an already established Drosophila melanogaster model of PD to test for early markers of neurodegeneration and if those markers are reversible following neuroprotective treatment. Specifically, we treat primary neuronal cultures with the neurotoxin 1-methyl-4-phenylpyridinium (MPP(+)) and track neuritic, dopaminergic mitochondria over time, observing a fragmenting change in their morphology before cell death. We then add a neuroprotective treatment (quinpirole, a D2 receptor agonist) at different timepoints to determine if the changes in mitochondrial morphology are reversible. We find that neuroprotective treatment must be added concomitantly to prevent changes in mitochondrial morphology and subsequent cell death. This work further supports Drosophila's use as a model organism and mitochondria's use as a biomarker for neurodegenerative disease. But mainly, this work highlights an import factor for experiments in neuroprotection - time of treatment. Our results highlight the problem that current neuroprotective treatments for PD may not be used the same way that they are tested experimentally.