Calcium Enabled Remote Loading of a Weak Acid Into pH-sensitive Liposomes and Augmented Cytosolic Delivery to Cancer Cells via the Proton Sponge Effect.

While delivery of chemotherapeutics to cancer cells by nanomedicines can improve therapeutic outcomes, many fail due to the low drug loading (DL), poor cellular uptake and endosomal entrapment. This study investigated the potential to overcome these limitations using pH-sensitive liposomes (PSL) empowered by the use of calcium acetate. An acidic dinitrobenzamide mustard prodrug SN25860 was used as a model drug, with non pH-sensitive liposomes (NPSL) as a reference. Calcium acetate as a remote loading agent allowed to engineer PSL- and NPSL-SN25860 with DL of > 31.1% (w/w). The IC50 of PSL-SN25860 was 21- and 141-fold lower than NPSL and free drug, respectively. At 48 h following injection of PSL-SN25860, NPSL-SN25860 and the free drug, drug concentrations in EMT6-nfsB murine breast tumors were 56.3 µg/g, 6.76 µg/g and undetectable (< 0.015 µg/g), respectively (n = 3). Meanwhile, the ex vivo tumor clonogenic assay showed 9.1%, 19.4% and 42.7% cell survival in the respective tumors. Live-cell imaging and co-localization analysis suggested endosomal escape was accomplished by destabilization of PSL followed by release of Ca2+ in endosomes allowing induction of a proton sponge effect. Subsequent endosomal rupture was observed approximately 30 min following endocytosis of PSL containing Ca2+. Additionally, calcium in liposomes promoted internalization of both PSL and NPSL. Taken together, this study demonstrated multifaceted functions of calcium acetate in promoting drug loading into liposomes, cellular uptake, and endosomal escape of PSL for efficient cytoplasmic drug delivery. The results shed light on designing nano-platforms for cytoplasmic delivery of various therapeutics.

[Investigation of the arsenic levels in ecosystem aspect in water type of endemic arsenicosis area in Datong City].

OBJECTIVE: To investigate the arsenic levels in endemic arsenism in Datong City, Shanxi Province. METHODS: A total of 85 inhabitants from one village in endemic arsenism area in Datong City, Shanxi Province were collected as research subjects. The People's Republic of China health industry standard for endemic arsenism was used to identify and diagnosis the patients. Daily drinking water and soil were collected and detected by atomic fluorescence spectrometry. The content of vegetables were detected by inductively coupled plasma mass spectrometry (ICP-MS). RESULTS: In the study, 85 samples were collected. Arsenic concentration in the daily drinking water were 14.41 - 90.34 µg/L, and the median value was 43.88 µg/L. The arsenic concentration of vegetables were 0.001 - 0.771 mg/kg, and 43.04% of samples, were higher than the maximal permissible limit of As in food. The results that the arsenic concentration of vegetables constant changes in the leaf vegetables > tubers > fruit vegetables. The health risk of intaking arsenic pollution in vegetables up to 71.77%. The arsenic levels in village of four directions were not exceeded the Chinese standards. CONCLUSIONS: Arsenic concentration in drinking water and vegetables are high in waterborn endemic arsenicosis area of Shanxi province. Arsenic in drinking water has been considered as a primary cause of arsenism, but direct intake of arsenic from vegetables can not be ignored.

Identification of Skp1 as a target of mercury sulfide for neuroprotection.

Mercury sulfide (HgS) exerts extensive biological effects on neuronal function. To investigate the direct target of HgS in neuronal cells, we developed a biotin-tagged HgS probe (bio-HgS) and employed an affinity purification technique to capture its target proteins. Then, we identified S-phase kinase-associated protein 1 (Skp1) as a potential target of HgS. Unexpectedly, we discovered that HgS covalently binds to Skp1 through a "Cys62-HgS-Cys120" mode. Moreover, our findings revealed that HgS inhibits the ubiquitin-protease system through Skp1 to up-regulate SNAP-25 expression, thereby triggering synaptic vesicle exocytosis to regulate locomotion ability in C. elegans. Collectively, our findings may promote a comprehensive interpretation of the pharmacological mechanism of mercury sulfide on neuroprotective function.

Oxidative DNA damage of peripheral blood polymorphonuclear leukocytes, selectively induced by chronic arsenic exposure, is associated with extent of arsenic-related skin lesions.

There is increasing evidence that oxidative stress is an important risk factor for arsenic-related diseases. Peripheral blood leukocytes constitute an important defense against microorganisms or pathogens, while the research on the impact of chronic arsenic exposure on peripheral blood leukocytes is much more limited, especially at low level arsenic exposure. The purpose of the present study was to explore whether chronic arsenic exposure affects oxidative stress of peripheral blood leukocytes and possible linkages between oxidative stress and arsenic-induced skin lesions. 75 male inhabitants recruited from an As-endemic region of China were investigated in the present study. The classification of arsenicosis was based on the degree of skin lesions. Arsenic levels were measured in drinking water and urine by Atomic Fluorescence Spectroscopy. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) was tested by Enzyme-Linked Immunosorbent Assay. 8-OHdG of peripheral blood leukocytes was evaluated using immunocytochemical staining. 8-OHdG-positive reactions were only present in polymorphonuclear leukocytes (PMNs), but not in monocytes (MNs). The 8-OHdG staining of PMN cytoplasm was observed in all investigated populations, while the 8-OHdG staining of PMN nuclei was frequently found along with the elevated amounts of cell debris in individuals with skin lesion. Urinary arsenic levels were increased in the severe skin lesion group compared with the normal group. No relationship was observed between drinking water arsenic or urine 8-OHdG and the degree of skin lesions. These findings indicated that the target and persistent oxidative stress in peripheral blood PMNs may be employed as a sensitive biomarker directly to assess adverse health effects caused by chronic exposure to lower levels of arsenic.

Clinical analysis of 114 cases of bronchiolitis in infants.

BACKGROUND: Bronchiolitis is a common lower respiratory tract infection in infants and young children. Severe cases may be accompanied by obvious dyspnea and oxygen saturation decline. AIM: To summarize the clinical features, standard diagnosis, and treatment of bronchiolitis. METHODS: This is a retrospective analysis of 114 pediatric patients (74 males, 40 females) who were first diagnosed as having bronchioles at the Department of Pediatrics of Tongling Maternal and Child Health Hospital from January 2019 to December 2019. The clinical features, imaging features, treatment, and other clinical data were recorded and analyzed. RESULTS: The age of onset of the disease was mainly from 1 mo to 6 mo (75.4%), and the time to hospital visit was mostly from the 2nd day to the 4th day of the course of the disease (75.4%). Lung imaging examination showed increase in lung texture, fuzzy (93.8%). The main treatment was atomization therapy: Budesonide combined with terbutaline (45.6%) and budesonide combined with salbutamol (38.5%). The average hospitalization time was 7.1 ± 2.4 d, and the overall cure rate was 94.7%. In patients without bacterial infection, the use of antibiotics significantly prolonged the length of hospital stay (7.8 ± 2.5 d vs 5.7 ± 1.8 d) and improved the cure rate (98.3% vs 87.9%, P < 0.05). CONCLUSION: Infants with bronchiolitis are mainly male and tend to have a good prognosis. However, the unneeded use of antibiotics may prolong the length of hospital stay significantly, which imposes the burden both on the patients and hospital system.

Enhancement of alkaline phytase production in Pichia pastoris: influence of gene dosage, sequence optimization and expression temperature.

Supplementation of animal feed with phytases has proven to be an effective strategy to alleviate phosphorous contamination of soil and water bodies. The inability of non-ruminant animals to digest phytates in corn and soybeans contributes to environmental contamination. Alkaline phytase from lily pollen (LlALP) exhibits unique catalytic and thermal stability properties that could be useful as a feed supplement. rLlALP2 was successfully expressed in Pichia pastoris; however, enzyme yields were modest (8-10 mg/L). In this paper, we describe our efforts to enhance rLlALP2 yield by investigating the influence of the following potential limiting factors: transgene copy number, codon bias, sequence optimization, and temperature during expression. Data presented indicate that increasing rLlAlp2 copy number was detrimental to heterologous expression, clones with one copy of wt-rLlAlp2 produced the highest activity, clones with two, four and seven or more copies produced 70%, 25% and 10% respectively, of enzyme activity implying that gene dosage is not limiting rLlALP2 yield. Use of a sequence-optimized rLlAlp2 increased the yield of the active enzyme by 25-50% in one/two copy clones, suggesting that translational efficiency is not a major bottleneck for rLlALP2 expression. Reducing the temperature during heterologous expression led to increases of 1.2-20-fold suggesting that protein folding and post-translational processes may be the dominant factors limiting rLlALP2 expression. Early knowledge of the transgene copy number allowed us to develop a more rational strategy for yield enhancement. Cumulatively, sequence optimization and temperature reduction led to the doubling of rLlALP2 enzyme activity in P. pastoris.

Neuroinflammation inhibition by small-molecule targeting USP7 noncatalytic domain for neurodegenerative disease therapy.

Neuroinflammation is a fundamental contributor to progressive neuronal damage, which arouses a heightened interest in neurodegenerative disease therapy. Ubiquitin-specific protease 7 (USP7) has a crucial role in regulating protein stability in multiple biological processes; however, the potential role of USP7 in neurodegenerative progression is poorly understood. Here, we discover the natural small molecule eupalinolide B (EB), which targets USP7 to inhibit microglia activation. Cocrystal structure reveals a previously undisclosed covalent allosteric site, Cys576, in a unique noncatalytic HUBL domain. By selectively modifying Cys576, EB allosterically inhibits USP7 to cause a ubiquitination-dependent degradation of Keap1. Keap1 function loss further results in an Nrf2-dependent transcription activation of anti-neuroinflammation genes in microglia. In vivo, pharmacological USP7 inhibition attenuates microglia activation and resultant neuron injury, thereby notably improving behavioral deficits in dementia and Parkinson's disease mouse models. Collectively, our findings provide an attractive future direction for neurodegenerative disease therapy by inhibiting microglia-mediated neuroinflammation by targeting USP7.

Intracellular detection and communication of a wireless chip in cell.

The rapid growth and development of technology has had significant implications for healthcare, personalized medicine, and our understanding of biology. In this work, we leverage the miniaturization of electronics to realize the first demonstration of wireless detection and communication of an electronic device inside a cell. This is a significant forward step towards a vision of non-invasive, intracellular wireless platforms for single-cell analyses. We demonstrate that a 25 [Formula: see text]m wireless radio frequency identification (RFID) device can not only be taken up by a mammalian cell but can also be detected and specifically identified externally while located intracellularly. The S-parameters and power delivery efficiency of the electronic communication system is quantified before and after immersion in a biological environment; the results show distinct electrical responses for different RFID tags, allowing for classification of cells by examining the electrical output noninvasively. This versatile platform can be adapted for realization of a broad modality of sensors and actuators. This work precedes and facilitates the development of long-term intracellular real-time measurement systems for personalized medicine and furthering our understanding of intrinsic biological behaviors. It helps provide an advanced technique to better assess the long-term evolution of cellular physiology as a result of drug and disease stimuli in a way that is not feasible using current methods.

Heterologous expression and functional characterization of a plant alkaline phytase in Pichia pastoris.

Phytases catalyze the sequential hydrolysis of phytic acid (myo-insositol hexakisphosphate), the most abundant inositol phosphate in cells. Phytic acid constitutes 3-5% of the dry weight of cereal grains and legumes such as corn and soybean. The high concentration of phytates in animal feed and the inability of non-ruminant animals such as swine and poultry to digest phytates leads to phosphate contamination of soil and water bodies. The supplementation of animal feed with phytases results in increased bioavailability to animals and decreased environmental contamination. Therefore, phytases are of great commercial importance. Phytases with a range of properties are needed to address the specific digestive needs of different animals. Alkaline phytase (LlALP1 and LlALP2) which possess unique catalytic properties that have the potential to be useful as feed and food supplement has been identified in lily pollen. Substantial quantities of alkaline phytase are needed for animal feed studies. In this paper, we report the heterologous expression of LlALP2 from lily pollen in Pichia pastoris. The expression of recombinant LlALP2 (rLlALP2) was optimized by varying the cDNA coding for LlALP2, host strain and growth conditions. The catalytic properties of recombinant LlALP2 were investigated extensively (substrate specificity, pH- and temperature dependence, and the effect of Ca(2+), EDTA and inhibitors) and found to be very similar to that of the native LlALP2 indicating that rLlALP2 from P. pastoris can serve as a potential source for structural and animal feed studies.

Different proteomic profiles of cinnabar upon therapeutic and toxic exposure reveal distinctive biological manifestations.

ETHNOPHARMACOLOGICAL RELEVANCE: Cinnabar, a traditional Chinese mineral medicine with sedative and tranquilizing effects, is known to be toxic to the neural system, but its detailed pharmacological and toxicological mechanisms are still unclear. AIM OF THE STUDY: This study aimed to explore the potential neuropharmacological and neurotoxicological mechanisms of cinnabar by investigating the differentially expressed proteins in cerebral cortices of mice exposed to therapeutic and toxic doses of cinnabar. MATERIALS AND METHODS: Label-free quantitative proteomics and bioinformatics analysis were used to characterize the proteins, pathways, and potential targets associated with therapeutic (50 mg/kg) and toxic (1000 mg/kg) doses of cinnabar in cerebral cortices of mice. Proteomic analysis was verified by parallel reaction monitoring. RESULTS: A total of 6370 and 6299 proteins were identified in the cerebral cortices of mice after exposure to therapeutic and toxic doses of cinnabar, among which 130 and 119 proteins were differentially expressed, respectively. Functional/pathway enrichment analysis showed that both exposure doses of cinnabar could affect transport processes in the cerebral cortex through different proteins. The changes induced by the therapeutic dose included pathways involved in translation and sphingolipid metabolism. Interestingly, for the toxic dose, differentially expressed proteins were enriched for functions and pathways related to RNA splicing, transcription, synaptic plasticity regulation and developmental processes, among which RNA splicing was the most significantly affected function. ATP6V1D and CX3CL1 were shown to be possible key proteins affected by cinnabar, leading to multiple functional changes in the cerebral cortex at the therapeutic and toxic doses, respectively. Furthermore, Connectivity Map (CMap) analysis predicted LRRK2 to be a potential therapeutic target and FTase to be a potential toxic target for cinnabar. CONCLUSION: Our results suggest that the pathways and potential targets identified in the mouse cerebral cortex exposed to therapeutic and toxic doses of cinnabar are different, which provides novel insights into the potential molecular mechanisms underlying the pharmacological and toxicological effects of cinnabar.

pH-Sensitive PEGylated liposomes for delivery of an acidic dinitrobenzamide mustard prodrug: Pathways of internalization, cellular trafficking and cytotoxicity to cancer cells.

This paper aims to develop and evaluate a pH-sensitive PEGylated liposomal (pPSL) system for tumor-targeted intracellular delivery of SN25860, a weakly acidic, poorly water-soluble dinitrobenzamide mustard prodrug which is activated by the E. coli nitroreductase nfB. pPSL and non pH-sensitive liposomes (nPSL), as reference, were formulated by thin-film hydration; an active drug loading method was developed with the aid of solubilizers. Cytotoxicity was evaluated in an nfsB-transfected EMT6 mouse mammary carcinoma cell line. Cellular uptake of liposomes was evaluated by both high performance liquid chromatography and flow cytometry. Intracellular trafficking was visualised by confocal microscopy. High drug loading (7.0±0.2% w/w) was achieved after systematic optimization of drug loading conditions. pPSL-SN25860 demonstrated a 21 and 24- fold increase in antiproliferative potency compared to nPSL-SN25860 and free drug, respectively. Cells treated with pPSL had a 1.6-2.5- fold increase in intracellular drug concentration compared to nPSL. This trend was consistent with flow cytometry results. Cells treated with chlorpromazine demonstrated reduced uptake of both nPSL (40%) and pPSL (46%), indicating clathrin-mediated endocytosis was the major pathway. Confocal microscopy showed that pPSL had not only undergone faster and greater endocytosis than nPSL but was also homogeneously distributed in the cytosol and nuclei suggesting endosome escape, in contrast to nPSL.

Mechanisms and biomaterials in pH-responsive tumour targeted drug delivery: A review.

As the mainstay in the treatment of various cancers, chemotherapy plays a vital role, but still faces many challenges, such as poor tumour selectivity and multidrug resistance (MDR). Targeted drug delivery using nanotechnology has provided a new strategy for addressing the limitations of the conventional chemotherapy. In the last decade, the volume of research published in this area has increased tremendously, especially with functional nano drug delivery systems (nanocarriers). Coupling a specific stimuli-triggered drug release mechanism with these delivery systems is one of the most prevalent approaches for improving therapeutic outcomes. Among the various stimuli, pH triggered delivery is regarded as the most general strategy, targeting the acidic extracellular microenvironment and intracellular organelles of solid tumours. In this review, we discuss recent advances in the development of pH-sensitive nanocarriers for tumour-targeted drug delivery. The review focuses on the chemical design of pH-sensitive biomaterials, which are used to fabricate nanocarriers for extracellular and/or intracellular tumour site-specific drug release. The pH-responsive biomaterials bring forth conformational changes in these nanocarriers through various mechanisms such as protonation, charge reversal or cleavage of a chemical bond, facilitating tumour specific cell uptake or drug release. A greater understanding of these mechanisms will help to design more efficient drug delivery systems to address the challenges encountered in conventional chemotherapy.

Extracellular expression of alkaline phytase in Pichia pastoris: Influence of signal peptides, promoters and growth medium.

Alkaline phytase isolated from pollen grains of Lilium longiflorum (LlALP) possesses unique catalytic and thermal stability properties that suggest it has the potential to be used as a feed supplement. However, substantial amounts of active enzymes are needed for animal feed studies and endogenous levels of LlALP in lily pollen are too low to provide the required amounts. Active rLlALP2 (coded by LlAlp2, one of two isoforms of alkaline phytase cDNA identified in lily pollen) has been successfully expressed in intracellular compartments of Pichia pastoris, however enzyme yields have been modest (25-30 mg/L) and purification of the enzyme has been challenging. Expression of foreign proteins to the extracellular medium of P. pastoris greatly simplifies protein purification because low levels of endogenous proteins are secreted by the yeast. In this paper, we first describe the generation of P. pastoris strains that will secrete rLlALP2 to the extracellular medium. Data presented here indicates that deletion of native signal peptides at the N- and C-termini of rLlALP2 enhanced α-mating factor (α-MF)-driven secretion by four-fold; chicken egg white lysozyme signal peptide was ineffective in the extracellular secretion of rLlALP2. Second, we describe our efforts to increase expression levels by employing a constitutive promoter from the glyceraldehyde-3-phosphate dehydrogenase gene (PGAP) in place of the strong, tightly controlled promoter of alcohol oxidase 1 gene (PAOX1). PGAP enhanced the extracellular expression levels of rLlALP2 compared to PAOX1. Finally, we report on the optimization of the culture medium to enhance yields of rLlALP2. The strength of PGAP varies depending on the carbon source available for cell growth; secreted expression of rLlALP2 was highest when glycerol was the carbon source. The addition of histidine and Triton X-100 also enhanced extracellular expression. Taken together, the employment of PGAP under optimized culture conditions resulted in approximately eight-fold (75-80 mg/L) increase in extracellular activity compared to PAOXI (8-10 mg/L). The P. pastoris expression system can be employed as a source of active alkaline phytase for animal feed studies.