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Autosomal recessive mutations in eukaryotic initiation factor 2B (eIF2B) cause leukoencephalopathy vanishing white matter with a wide clinical spectrum. eIF2B comprises five subunits (α-ε; genes EIF2B1, 2, 3, 4 and 5) and is the guanine nucleotide-exchange factor (GEF) for eIF2. It plays a key role in protein synthesis. Here, we have studied the functional effects of selected VWM mutations in EIF2B2-5 by coexpressing mutated and wild-type subunits in human cells. The observed functional effects are very diverse, including defects in eIF2B complex integrity; binding to the regulatory α-subunit; substrate binding; and GEF activity. Activity data for recombinant eIF2B complexes agree closely with those for patient-derived cells with the same mutations. Some mutations do not affect these parameters even though they cause severe disease. These findings are important for three reasons; they demonstrate that measuring eIF2B activity in patients' cells has limited value as a diagnostic test; they imply that severe disease can result from alterations in eIF2B function other than defects in complex integrity, substrate binding or GEF activity, and last, the diversity of functional effects of VWM mutations implies that seeking agents to manage or treat VWM should focus on downstream effectors of eIF2B, not restoring eIF2B activity.

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G-quadruplex structure aptamer (PS2.M) can capture acridine orange (AO) from reduced graphene oxide (rGO). When the AO-PS2.M/rGO mixture is incubated with hemin, the specific binding of hemin with PS2.M results in a release of AO from PS2.M and return of AO back to rGO. Based on the quenching of fluorescence, the target hemin was detected sensitively and selectively, giving a detection limit of 50 nM.

In the presence of graphene oxide, upon formation of cytosine-Ag-cytosine the fluorescence wavelength of FAM-labeled DNA exhibited a red shift, and its intensity significantly increased. A novel fluorescent DNA sensor for Ag(+) and cysteine detection, and a dual-output fluorescent DNA INHIBIT logic gate are designed.

A well-known traditional Chinese medicinal prescription, Oren-gedoku-to (OGT), has been used in clinical therapies for many types of dementia in China and Japan. Additionally, it ameliorates the age-related deterioration of learning and memory in an Alzheimer's disease (AD) rat model. Indoleamine 2, 3-dioxygenase (IDO-1) is the first and rate-limiting enzyme in the kynurenine pathway of tryptophan catabolism, which ultimately leads to the production of the excitotoxin quinolinic acid (QUIN). IDO-1 has recently been established as one of the key players involved in the pathogenesis of AD. OGT is indicated to prevent cholinergic dysfunction and reduce oxidative stress; however, the exact mechanism underlying its ability to improve cognitive ability remains elusive. Here we present a novel mechanism of OGT's therapeutic potential in AD. We demonstrated that OGT significantly inhibited recombinant human IDO-1 (rhIDO-1) activity in vitro, and its four main constituents (i.e., berberine, palmatine, jatrorrhizine, and baicalein) were potent IDO-1 inhibitors. IC50 values, obtained from a cell-based assay, of HEK 293 cells and an enzymatic assay were much lower than the most commonly used IDO-1 inhibitor, 1-methyl tryptophan (1-MT). Berberine was the best inhibitor and had IC50 values of 7 μM (cell-based assay) and 9.3 μM (enzymatic assay). Jatrorrhizine and palmatine exhibited irreversible inhibition of rhIDO-1, whereas berberine and baicalein behaved as uncompetitive, reversible inhibitors with Ki values of 8 μM and 215 μM, respectively. In conclusion, constituents of OGT show strong IDO-1 inhibitory activity and may have significant therapeutic potential for AD.

Purpose: Systemic administration of free chemotherapeutic drugs leads to severe toxic effects, and physiological characteristics of solid tumors restrain the drugs from reaching the hypoxic regions. E. coli Nissle 1917 (EcN) has been known to penetrate the barrier and proliferate in the interface between the viable and necrotic regions of tumors. This study aimed to fabricate a nanoscale minicell via genetic engineering of EcN for targeted delivery of chemotherapeutic drugs to the hypoxic regions of tumors for cancer therapy.Methods: A large number of minicells were produced by knocking out the minCD gene and enhancing the minE expression in EcN. Then, a pH (low) insertion peptide (pHLIP) was displayed on the membrane surface through protein display technology to endow the cells with the ability to target the acidic microenvironments of tumors. The acidic-microenvironment targeting ability and therapeutic effect of the engineered minicells with chemotherapeutic drugs was thoroughly evaluated by using breast cancer cells and an orthotopic model of breast tumor.Results: The EcN-derived minicells displaying pHLIP could be directly extracted from the fermentation broth and used for delivering chemotherapeutic drugs without any further modification. Targeting of doxorubicin (DOX)-loaded minicells to cancer cells via pHLIP resulted in rapid internalization and drug release in acidic media. Importantly, the pHLIP-mosaic minicells successfully invaded the necrotic and hypoxic regions of orthotopic breast cancers where free chemotherapeutic drugs could never get to because of vascular insufficiency and high interstitial fluid pressure. This invasion resulted in significant regression of an orthotopic breast tumor in a mouse model, while no seriously pathogenic effects were observed during the animal experiments.Conclusions: This study provides a novel strategy for the fabrication of tumor-targeting carriers via genetic engineering based on biomaterials with the ability to penetrate hypoxic regions of tumors, high biocompatibility and low toxicity.