BMP/Smad Pathway Is Involved in Lithium Carbonate-Induced Neural-Tube Defects in Mice and Neural Stem Cells.

Neural-tube defects (NTDs) are one type of the most serious birth defects. Studies have shown that inositol deficiency is closely related to the occurrence of NTDs. Bone morphogenetic protein (BMP)-mediated Smad signaling pathways have been implicated in neurogenesis and neural-tube closure. However, the role of the BMP/Smad pathway in inositol-deficiency-induced NTDs remains unclear. Inositol-deficiency models in C57 mice and mouse neural stem cells (mNSCs) were induced with Li2CO3 treatment or inositol withdrawal. The role of the BMP/Smad pathway in the regulation of cell proliferation and the development of NTDs was determined utilizing qRT-PCR, HE staining, Western blot, immunostaining, MTT assay, EdU staining, and flow cytometry. The intraperitoneal injection of Li2CO3 at Embryonic Day 7.5 induced the occurrence of NTDs. The mRNA levels of Bmp2, Bmp4, Smad1, Smad5, Smad8 and Runx2, the phosphorylation of Smad1/5/8, and the nuclear translocation of Runx2 were significantly increased in NTD embryonic brain tissues and mNSCs exposed to Li2CO3 or an inositol-free medium, which were suppressed by BMP receptor selective inhibitor LDN-193189. The Li2CO3-induced phosphorylation of Smad1/5/8 was inhibited by inositol supplementation. Cell proliferation was significantly promoted by Li2CO3 exposure or the absence of inositol in mNSCs, which was reversed by LDN-193189. These results suggest that the activation of the BMP/Smad signaling pathway might play an important role in the development of NTDs induced by maternal Li2CO3 exposure via inositol deficiency.

Peptide supplementation relieves stress and enhances glycolytic flux in filamentous fungi during organic acid bioproduction.

Filamentous fungi occupy a uniquely favorable position in the bioproduction of organic acids. Intracellular stress is the main stimulator in filamentous fungi to produce and accumulate organic acids with high flux. However, stress can affect the physiological activities of filamentous fungi, thereby deteriorating their fermentation performance. Herein, we report that peptide supplementation during Rhizopus oryzae fermentation significantly improved fumaric acid production. Specifically, fumaric acid productivity was elevated by approximately 100%, fermentation duration was shortened from 72 to 36 h, while maintaining the final titer. Furthermore, transcriptome profile analysis and biochemical assays indicated that the overall capabilities of the stress defense systems (enzymatic and nonenzymatic) were significantly improved in R. oryzae. Consequently, glycolytic metabolism was distinctly enhanced, which eventually resulted in improved fumaric acid production and reduced fermentation duration. We expect our findings and efforts to provide essential insights into the optimization of the fermentation performance of filamentous fungi in industrial biotechnology and fermentation engineering.

Osteopontin Promotes Hepatic Progenitor Cell Expansion and Tumorigenicity via Activation of ß-Catenin in Mice.

Upregulation of osteopontin (OPN) has been found in hepatic progenitor cells (HPCs) in several liver diseases with portal biliary proliferation. Here, we investigated the role of HPC-derived autocrine OPN in regulating HPC expansion, migration, and hepatocarcinogenesis in mice. Five-week-old, weighing between 18 and 20 g of either wild type (WT) or OPN gene knockout (OPN-KO) male mice were treated with modified choline-deficient, ethionine-supplemented diet (modified choline-deficient [MCDE]) for 2 weeks to induce HPC production, or 6-12 months to induce tumorigenesis. Epithelial cell adhesion molecule EpCAM(+) CD45(-) cells isolated from mouse liver and liver epithelial progenitor cells were used for in vitro study. OPN was blocked by specific antibody or RNAi-mediated silence to investigate the role of OPN. To evaluate correlation between OPN expression and ß-catenin activity, expressions of OPN and ß-catenin were assessed in human liver cancer specimens. We found autocrine OPN promotes HPC expansion and migration by decreasing membranous E-cadherin and increasing free cytoplasmic ß-catenin via binding to αv integrin and activating Src activity. Depletion of OPN significantly attenuated MCDE-induced hepatocarcinogenesis. Clinical evidence revealed a strong correlation of high OPN expression with cytoplasmic/nuclear expression of ß-catenin in 43 cases of human combined hepatocellular carcinoma and cholangiocarcinoma and mixed intrahepatic cholangiocarcinoma and 80 cases of hepatocellular carcinoma. Our results indicate that autocrine OPN plays a crucial role in HPC expansion, migration, and subsequent oncogenic transformation of HPCs, which may provide a new insight into hepatocarcinogenesis.