Geniposide Increases Unfolded Protein Response-Mediating HRD1 Expression to Accelerate APP Degradation in Primary Cortical Neurons

Altered proteostasis induced by amyloid peptide aggregation and hyperphosphorylation of tau protein, is a prominent feature of Alzheimer’s disease, which highlights the occurrence of endoplasmic reticulum stress and triggers the activation of the unfolded protein response (UPR), a signaling pathway that enforces adaptive programs to sustain proteostasis. In this study, we investigated the role of geniposide in the activation of UPR induced by high glucose in primary cortical neurons. We found that high glucose induced a significant activation of UPR, and geniposide enhanced the effect of high glucose on the phosphorylation of IRE1α, the most conserved UPR signaling branch. We observed that geniposide induced the expression of HRD1, an ubiquitin-ligase E3 in a time dependent manner, and amplified the expression of HRD1 induced by high glucose in primary cortical neurons. Suppression of IRE1α activity with STF-083010, an inhibitor of IRE1 phosphorylation, prevented the roles of geniposide on the expression of HRD1 and APP degradation in high glucose-treated cortical neurons. In addition, the results from RNA interfere on HRD1 revealed that HRD1 was involved in geniposide regulating APP degradation in cortical neurons. These data suggest that geniposide might be benefit to re-establish proteostasis by enhancing the UPR to decrease the load of APP in neurons challenged by high glucose.     

Aligned electrospun fibers for neural patterning

Objectives

To test a 3D approach for neural network formation, alignment, and patterning that is reproducible and sufficiently stable to allow for easy manipulation.

Results

A novel cell culture system was designed by engineering a method for the directional growth of neurons. This uses NG108-15 neuroblastoma x glioma hybrid cells cultured on suspended and aligned electrospun fibers. These fiber networks improved cellular directionality, with alignment angle standard deviations significantly lower on fibers than on regular culture surfaces. Morphological studies found nuclear aspect ratios and cell projection lengths to be unchanged, indicating that cells maintained neural morphology while growing on fibers and forming a 3D network. Furthermore, fibronectin-coated fibers enhanced neurite extensions for all investigated time points. Differentiated neurons exhibited significant increases in average neurite lengths 96 h post plating, and formed neurite extensions parallel to suspended fibers, as visualized through scanning electron microscopy.

Conclusions

The developed model has the potential to serve as the basis for advanced 3D studies, providing an original approach to neural network patterning and setting the groundwork for further investigations into functionality.

     

Chitosan enhanced gene delivery of cationic liposome via non-covalent conjugation

Two new types of stable ternary complexes were formed by mixing chitosan with DOTAP/pDNA lipoplex and DOTAP with chitosan/pDNA polyplex via non-covalent conjugation for the efficient delivery of plasmid DNA. They were characterized by atomic force microscopy, gel retarding, and dynamic light scattering. The DOTAP/CTS/pDNA complexes were in compacted spheroids and irregular lump of larger aggregates in structure, while the short rod- and toroid-like and donut shapes were found in CTS/DOTAP/pDNA complexes. The transfection efficiency of the lipopolyplexes showed higher GFP gene expression than DOTAP/pDNA and CTS/pDNA controls in Hep-2 and Hela cells, and luciferase gene expression 2–3-fold than DOTAP/pDNA control and 70–120-fold than CTS/pDNA control in Hep-2 cells. The intracellular trafficking was examined by confocal laser scanning microscopy. Rapid pDNA delivery to the nucleus enchanced by chitosan was achieved after 4 h transfection.     

A robust six-miRNA prognostic signature for head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) remains a major health problem worldwide. We aimed to identify a robust microRNA (miRNA)-based signature for predicting HNSCC prognosis. The miRNA expression profiles of HNSCC were obtained from The Cancer Genome Atlas (TCGA) database. The TCGA HNSCC cohort was randomly divided into the discovery and validation cohort. A miRNA-based prognostic signature was built up based on TGCA discovery cohort, and then further validated. The downstream targets of prognostic miRNAs were subjected to functional enrichment analyses. The role of miR-1229-3p, a prognosis-related miRNA, in tumorigenesis of HNSCC was further evaluated. A total of 305 significantly differentially expressed miRNAs were found between HNSCC samples and normal tissues. A six-miRNA prognostic signature was constructed, which exhibited a strong association with overall survival (OS) in the TCGA discovery cohort. In addition, these findings were successfully confirmed in TCGA validation cohort and our own independent cohort. The miRNA-based signature was demonstrated as an independent prognostic indicator for HNSCC. A risk signature-based nomogram model was constructed and showed good performance for predicting the OS for HNSCC. The functional analyses revealed that the downstream targets of these prognostic miRNAs were closely linked to cancer progression. Mechanistically, in vitro analysis revealed that miR-1229-3p played a tumor promoting role in HNSCC. In conclusion, our study has developed a robust miRNA-based signature for predicting the prognosis of HNSCC with high accuracy, which will contribute to improve the therapeutic outcome.     

Tethered Spectroscopic Probes Estimate Dynamic Distances with Subnanometer Resolution in Voltage-Dependent Potassium Channels

Measurements of inter- and intramolecular distances are important for monitoring structural changes and understanding protein interaction networks. Fluorescence resonance energy transfer and functionalized chemical spacers are the two predominantly used strategies to map short-range distances in living cells. Here, we describe the development of a hybrid approach that combines the key advantages of spectroscopic and chemical methods to estimate dynamic distance information from labeled proteins. Bifunctional spectroscopic probes were designed to make use of adaptable-anchor and length-varied spacers to estimate molecular distances by exploiting short-range collisional electron transfer. The spacers were calibrated using labeled polyproline peptides of defined lengths and validated by molecular simulations. This approach was extended to estimate distance restraints that enable us to evaluate the resting-state model of the Shaker potassium channel.     

The detrimental effect of iron on OA chondrocytes: Importance of pro-inflammatory cytokines induced iron influx and oxidative stress

Iron overload is common in elderly people which is implicated in the disease progression of osteoarthritis (OA), however, how iron homeostasis is regulated during the onset and progression of OA and how it contributes to the pathological transition of articular chondrocytes remain unknown. In the present study, we developed an in vitro approach to investigate the roles of iron homeostasis and iron overload mediated oxidative stress in chondrocytes under an inflammatory environment. We found that pro-inflammatory cytokines could disrupt chondrocytes iron homeostasis via upregulating iron influx transporter TfR1 and downregulating iron efflux transporter FPN, thus leading to chondrocytes iron overload. Iron overload would promote the expression of chondrocytes catabolic markers, MMP3 and MMP13 expression. In addition, we found that oxidative stress and mitochondrial dysfunction played important roles in iron overload-induced cartilage degeneration, reducing iron concentration using iron chelator or antioxidant drugs could inhibit iron overload-induced OA-related catabolic markers and mitochondrial dysfunction. Our results suggest that pro-inflammatory cytokines could disrupt chondrocytes iron homeostasis and promote iron influx, iron overload-induced oxidative stress and mitochondrial dysfunction play important roles in iron overload-induced cartilage degeneration.     

A novel human polycomb binding site acts as a functional polycomb response element in Drosophila

Polycomb group (PcG) proteins are key chromatin regulators implicated in multiple processes including embryonic development, tissue homeostasis, genomic imprinting, X-chromosome inactivation, and germ cell differentiation. The PcG proteins recognize target genomic loci through cis DNA sequences known as Polycomb Response Elements (PREs), which are well characterized in Drosophila. However, mammalian PREs have been elusive until two groups reported putative mammalian PREs recently. Consistent with the existence of mammalian PREs, here we report the identification and characterization of a potential PRE from human T cells. The putative human PRE has enriched binding of PcG proteins, and such binding is dependent on a key PcG component SUZ12. We demonstrate that the putative human PRE carries both genetic and molecular features of Drosophila PRE in transgenic flies, implying that not only the trans PcG proteins but also certain features of the cis PREs are conserved between mammals and Drosophila.