The objective of this study was to evaluate the delivery of nasally administered aerosols to the lungs during noninvasive ventilation using controlled condensational growth techniques.
An optimized mixer, combined with a mesh nebulizer, was used to generate submicrometer aerosol particles using drug alone (albuterol sulfate) and with mannitol or sodium chloride added as hygroscopic excipients. The deposition and growth of these particles were evaluated in an adult nose-mouth-throat (NMT) model using in vitro experimental methods and computational fluid dynamics simulations.
Significant improvement in the lung dose (3–4x increase) was observed using excipient enhanced growth (EEG) and enhanced condensational growth (ECG) delivery modes compared to control studies performed with a conventional size aerosol (~5μm). This was due to reduced device retention and minimal deposition in the NMT airways. Increased condensational growth of the initially submicrometer particles was observed using the ECG mode and in the presence of hygroscopic excipients. CFD predictions for regional drug deposition and aerosol size increase were in good agreement with the observed experimental results.
These controlled condensational growth techniques for the delivery of submicrometer aerosols were found to be highly efficient methods for delivering nasally-administered drugs to the lungs.
Combination drug-excipient particles; enhanced condensational growth; excipient enhanced growth; hygroscopic growth; noninvasive aerosol therapy; nose-to-lung aerosol delivery
Previous studies have characterized the size increase of combination submicrometer particles composed of a drug and hygroscopic excipient when exposed to typical airway thermodynamic conditions. The objective of this study was to determine the deposition and size increase characteristics of excipient enhanced growth (EEG) aerosols throughout the tracheobronchial (TB) airways and to evaluate the potential for targeted delivery.
Submicrometer particles composed of a poorly water-soluble drug (insulin) and hygroscopic excipient (sodium chloride) were considered at drug:excipient mass ratios of 50:50 and 25:75. A previously validated computational fluid dynamics model was used to predict aerosol size increase and deposition in characteristic geometries of the mouth–throat (MT), upper TB airways through the third bifurcation (B3), and remaining TB airways through B15. Additional validation experiments were also performed for albuterol sulfate:mannitol particles. Both growth of combination particles and deposition are reported throughout the conducting airways for characteristic slow and deep (SD) and quick and deep (QD) inhalations.
For all EEG cases considered, MT deposition was less than 1% of the drug dose, which is at least one order of magnitude lower than with state-of-the-art and conventional inhalers. Final aerosol sizes exiting the TB region and entering the alveolar airways were all greater than 3 μm. For SD inhalation, deposition fractions of 20% were achieved in the lower TB region of B8–B15, which is a factor of 20–30×higher than conventional delivery devices. With QD inhalation, maximum alveolar delivery of 90% was observed.
Increasing the dose delivered to the lower TB region by a factor of 20–30×or achieving 90% delivery to the alveolar airways was considered effective aerosol targeting compared with conventional devices. The trend of higher flow rates resulting in better alveolar delivery of aerosols is unique to EEG and may be used to design highly efficient dry powder inhalers.
respiratory drug delivery; excipient enhanced growth (EEG); nanoaerosols; hygroscopic droplet growth; engineered combination particles; stochastic individual path (SIP) airway modeling; computational fluid dynamics (CFD) simulations; in vitro aerosol experiments
In prolonged hemorrhagic shock, reductions in intestinal mucosal blood perfusion lead to mucosal barrier damage and systemic inflammation. Gastrointestinal failure in critically ill patients has a poor prognosis, so early assessment of mucosal barrier injury in shock patients is clinically relevant. Unfortunately, there is no serum marker that can accurately assess intestinal ischemia-reperfusion injury.
The aim of this study was to assess if serum diamine oxidase levels can reflect intestinal mucosal injury subsequent to prolonged hemorrhagic shock.
Thirty New Zealand white rabbits were divided into three groups: a control group, a medium blood pressure (BP) group (exsanguinated to a shock BP of 50 to 41 mm Hg), and a low BP group (exsanguinated to a shock blood pressure of 40 to 31 mm Hg), in which the shock BP was sustained for 180 min prior to fluid resuscitation.
The severity of hemorrhagic shock in the low BP group was significantly greater than that of the medium BP group according to the post-resuscitation BP, serum tumor necrosis factor (TNF)-α, and arterial lactate. Intestinal damage was significantly more severe in the low BP group according to Chiu’s scoring, claudin-1, intercellular adhesion molecule (ICAM)-1, and myeloperoxidase expression. Serum diamine oxidase was significantly increased in the low BP group compared to the medium BP and control groups and was negatively correlated with shock BP.
Serum diamine oxidase can be used as a serological marker in evaluating intestinal injury and shows promise as an indicator of hemorrhagic shock severity.
The aim of this study was to evaluate and modify commercial dry powder inhalers (DPIs) for the aerosolization of a submicrometer excipient enhanced growth (EEG) formulation. The optimized device and formulation combination was then tested in a realistic in vitro mouth-throat - tracheobronchial (MT-TB) model. An optimized EEG submicrometer powder formulation, consisting of albuterol sulfate (drug), mannitol (hygroscopic excipient), L-leucine (dispersion enhancer) and poloxamer 188 (surfactant) in a ratio of 30:48:20:2 was prepared using a Büchi Nano spray dryer. The aerosolization performance of the EEG formulation was evaluated with 5 conventional DPIs: Aerolizer, Novolizer, HandiHaler, Exubera and Spiros. To improve powder dispersion, the HandiHaler was modified with novel mouth piece (MP) designs. The aerosol performance of each device was assessed using a next generation impactor (NGI) at airflow rates generating a pressure drop of 4 kPa across the DPI. In silico and in vitro deposition and hygroscopic growth of formulations was studied using a MT-TB airway geometry model. Both Handihaler and Aerolizer produced high emitted doses (ED) together with a significant submicrometer aerosol fraction. A modified HandiHaler with a MP including a three-dimensional (3D) array of rods (HH-3D) produced a submicrometer particle fraction of 38.8% with a conventional fine particle fraction (% <5µm) of 97.3%. The mass median diameter (MMD) of the aerosol was reduced below 1 µm using this HH-3D DPI. The aerosol generated from the modified HandiHaler increased to micrometer size (2.8 µm) suitable for pulmonary deposition, when exposed to simulated respiratory conditions, with negligible mouth-throat (MT) deposition (2.6 %).
excipient enhanced growth (EEG); spray drying; hygroscopic aerosol; dry powder inhaler (DPI); aerosolization
Bacterial colonisation of the gut is involved in the development of colitis-associated colorectal cancer. However, it remains unclear how the gut microbiota dynamically shifts correlating with colorectal carcinogenesis. Here, we reveal the longitudinal shifts in the microbial community that occur with colitis-associated colorectal cancer. High-throughput sequencing results for the bacterial 16S rRNA gene (V3 region) were compared for azoxymethane/dextran sodium sulphate-treated mice and control mice. We found that microbial community structure was significantly altered by chronic colitis. Microbes in the species Streptococcus luteciae, Lactobacillus hamster, Bacteroides uniformis and Bacteroides ovatus were increased during colorectal carcinogenesis. Histological measurements for a molecular network including six interconnected key factors from inflammation to cancer, namely p65, p53, COX-2, PPARγ, CCR2 and β-catenin, indicated that the microbiome modifications were correlated with molecular pathogenesis of colitis-associated colorectal cancer. Phylotype modifications after each AOM/DSS cycle were identified. A longitudinal microbial network was then constructed for the gut microbiome and showed that the phylotype shifts during this process were complex and highly dynamic. This work may provide a deeper understanding of the role of the microbiota and microbe-host interactions in colitis-associated colorectal cancer.
AIM: To study the effects of cortactin on the tumor biology of SGC-7901 cells and identify the mechanism involved in the process.
METHODS: Cell lines in which cortactin was stably overexpressed or knocked down as well as the respective control cell lines were established by standard molecular methods. The effects of cortactin on the proliferation, migration and invasion capacity of SGC-7901 cells were assessed by the MTT assay, colony formation, flow cytometry, transwell migration and matrigel invasion. Nude mouse models were also used to assess the role of cortactin in the growth and metastasis of SGC-7901 cells in vivo. Western blotting analysis was performed to detect the expression of epidermal growth factor receptor (EGFR) and downstream molecules.
RESULTS: Cell lines in which cortactin was stably overexpressed or knocked down as well as control cell lines were successfully established and designated as LV5-cortactin-SGC, LV5-SGC, LV3-shRNA-SGC and LV3-SGC. Cortactin overexpression promoted SGC-7901 cell migration (340.7 ±12.6 vs 229.1 ± 23.2, P < 0.01) and invasion (71.6 ± 5.2 vs 48.4 ± 3.6, P < 0.01). Cortactin downregulation impaired SGC-7901 cell migration (136.2 ± 19.8 vs 225 ± 17) and invasion (29.2 ± 5.2 vs 49.6 ± 3.8, P < 0.01). The results from the MTT and colony formation assays results indicated increased LV5-cortactin-SGC cell proliferation and decreased LV3-shRNA-SGC cell proliferation compared to the control cells. Flow cytometry analysis demonstrated that cortactin overexpression promoted the proliferation index of SGC-7901 cells, and the results were reversed when cortactin was downregulated. Mouse tumor models confirmed that cortactin expression increased SGC-7901 cell proliferation and metastasis in vivo. Western blotting analysis revealed that cortactin elevated EGFR expression and activated the downstream molecules.
CONCLUSION: Cortactin expression promoted the migration, invasion and proliferation of SGC-7901 cells both in vivo and in vitro. The EGFR signaling pathway is mechanistically involved.
Gastric cancer; Cortactin; Epidermal growth factor receptor; Invasion; Metastasis; Proliferation
matter (PM) air pollution poses a formidable public
health threat to the city of Beijing. Among the various hazards of
PM pollutants, microorganisms in PM2.5 and PM10 are thought to be responsible for various allergies and for the
spread of respiratory diseases. While the physical and chemical properties
of PM pollutants have been extensively studied, much less is known
about the inhalable microorganisms. Most existing data on airborne
microbial communities using 16S or 18S rRNA gene sequencing to categorize
bacteria or fungi into the family or genus levels do not provide information
on their allergenic and pathogenic potentials. Here we employed metagenomic
methods to analyze the microbial composition of Beijing’s PM
pollutants during a severe January smog event. We show that with sufficient
sequencing depth, airborne microbes including bacteria, archaea, fungi,
and dsDNA viruses can be identified at the species level. Our results
suggested that the majority of the inhalable microorganisms were soil-associated
and nonpathogenic to human. Nevertheless, the sequences of several
respiratory microbial allergens and pathogens were identified and
their relative abundance appeared to have increased with increased
concentrations of PM pollution. Our findings may serve as an important
reference for environmental scientists, health workers, and city planners.
Using next-generation sequencing technology alone, we have successfully generated and assembled a draft sequence of the giant panda genome. The assembled contigs (2.25 gigabases (Gb)) cover approximately 94% of the whole genome, and the remaining gaps (0.05 Gb) seem to contain carnivore-specific repeats and tandem repeats. Comparisons with the dog and human showed that the panda genome has a lower divergence rate. The assessment of panda genes potentially underlying some of its unique traits indicated that its bamboo diet might be more dependent on its gut microbiome than its own genetic composition. We also identified more than 2.7 million heterozygous single nucleotide polymorphisms in the diploid genome. Our data and analyses provide a foundation for promoting mammalian genetic research, and demonstrate the feasibility for using next-generation sequencing technologies for accurate, cost-effective and rapid de novo assembly of large eukaryotic genomes.
Epigenetics is essentially a phenotypical change in gene expression without any alteration of the DNA sequence; the emergence of epigenetics in cancer research and mainstream oncology is fueling new hope. However, it is not yet known whether this knowledge will translate to improved clinical management of ovarian cancer. In this malignancy, women are still undergoing chemotherapy similar to what was approved in 1978, which to this day represents one of the biggest breakthroughs for treating ovarian cancer. Although liquid tumors are benefiting from epigenetically related therapies, solid tumors like ovarian cancer are not (yet?). Herein, we will review the science of molecular epigenetics, especially DNA methylation, histone modifications and microRNA, but also include transcription factors since they, too, are important in ovarian cancer. Pre-clinical and clinical research on the role of epigenetic modifications is also summarized. Unfortunately, ovarian cancer remains an idiopathic disease, for the most part, and there are many areas of patient management, which could benefit from improved technology. This review will also highlight the evidence suggesting that epigenetics may have pre-clinical utility in pharmacology and clinical applications for prognosis and diagnosis. Finally, drugs currently in clinical trials (i.e., histone deacetylase inhibitors) are discussed along with the promise for epigenetics in the exploitation of chemoresistance. Whether epigenetics will ultimately be the answer to better management in ovarian cancer is currently unknown; but we hope so in the future.
microRNA; ovarian cancer; epigenetics; DNA methylation; histone modifications
Mouse strains show polymorphisms in the amino acid sequences of serum amyloid A 1 (SAA1)
and serum amyloid A 2 (SAA2). Major laboratory mouse strains are classified based on the
sequence as carrying the A haplotype (e.g., BALB/c) or B
haplotype (e.g., SJL/J) of the Saa1 and Saa2 gene unit.
We attempted to elucidate the diversity of the mouse Saa1 and
Saa2 family genes at the nucleotide sequence level by a systematic
survey of 6 inbred mouse strains from 4 Mus subspecies, including
Mus musculus domesticus, Mus musculus musculus,
Mus musculus castaneus, and Mus spretus.
Saa1 and Saa2 genes were obtained from the mouse
genome by PCR amplification, and each full-length nucleotide sequence was determined. We
found that Mus musculus castaneus mice uniquely possess 2 divergent
Saa1 genes linked on chromosome 7. Overall, the mouse strains had
distinct composite patterns of amino acid substitutions at 9 positions in SAA1 and SAA2
isoforms. The mouse strains also had distinct composite patterns of 2 polymorphic upstream
regulatory elements that influenced gene transcription in in vitro
reporter assays. B haplotype mice were revealed to possess an LTR
insertion in the downstream region of Saa1. Collectively, these results
indicate that the mouse Saa genes hold broader diversity and greater
complexity than previously known, and these characteristics were likely attained through
gene duplication and repeated gene conversion events in the Mus
gene conversion; gene duplication; Mus subspecies; polymorphism; serum amyloid A
Excipient enhanced growth (EEG) of inhaled submicrometer pharmaceutical aerosols is a recently proposed method intended to significantly reduce extrathoracic deposition and improve lung delivery. The objective of this study was to evaluate the size increase of combination drug and hygroscopic excipient particles in a characteristic model of the airways during inhalation using both in vitro experiments and CFD simulations. The airway model included a characteristic mouth-throat (MT) and upper tracheobronchial (TB) region through the third bifurcation (B3) and was enclosed in a chamber geometry used to simulate the thermodynamic conditions of the lungs. Both in vitro results and CFD simulations were in close agreement and indicated that EEG delivery of combination submicrometer particles could nearly eliminate MT deposition for inhaled pharmaceutical aerosols. Compared with current inhalers, the proposed delivery approach represents a 1–2 order of magnitude reduction in MT deposition. Transient inhalation was found to influence the final size of the aerosol based on changes in residence times and relative humidity values. Aerosol sizes following EEG when exiting the chamber (2.75–4.61 μm) for all cases of initial submicrometer combination particles were equivalent to or larger than many conventional pharmaceutical aerosols that frequently have MMADs in the range of 2–3 μm.
Respiratory drug delivery; nanoaerosols; hygroscopic droplet growth; excipient enhanced growth; targeted aerosol deposition; characteristic airway model
The proteasomal ATPase ring, comprising Rpt1-Rpt6, associates with the heptameric α ring of the proteasome core particle (CP) in the mature proteasome, with the Rpt C-terminal tails inserting into pockets of the α ring1–4. Rpt ring assembly is mediated by four chaperones, each binding a distinct Rpt subunit5–10. We report that the base subassembly of the proteasome, which includes the Rpt ring, forms a high affinity complex with the CP. This complex is subject to active dissociation by the chaperones Hsm3, Nas6, and Rpn14. Chaperone-mediated dissociation was abrogated by a nonhydrolyzable ATP analog, indicating that chaperone action is coupled to nucleotide hydrolysis by the Rpt ring. Unexpectedly, synthetic Rpt tail peptides bound α pockets with poor specificity, except for Rpt6, which uniquely bound the α2/α3 pocket. Although the Rpt6 tail is not visualized within an α pocket in mature proteasomes2–4, it inserts into the α2/α3 pocket in the base-CP complex and is important for complex formation. Thus, the Rpt-CP interface is reconfigured when the lid complex joins the nascent proteasome to form the mature holoenzyme.
proteasome; chaperone; single particle cryoEM; ATPase
Residents of the Tibetan Plateau show heritable adaptations to extreme altitude. We sequenced 50 exomes of ethnic Tibetans, encompassing coding sequences of 92% of human genes, with an average coverage of 18X per individual. Genes showing population-specific allele frequency changes, which represent strong candidates for altitude adaptation, were identified. The strongest signal of natural selection came from EPAS1, a transcription factor involved in response to hypoxia. One SNP at EPAS1 shows a 78% frequency difference between Tibetan and Han samples, representing the fastest allele frequency change observed at any human gene to date. This SNP’s association with erythrocyte abundance supports the role of EPAS1 in adaptation to hypoxia. Thus, a population genomic survey has revealed a functionally important locus in genetic adaptation to high altitude.
Genome-wide association studies have mainly relied on common HapMap sequence variations. Recently, sequencing approaches have allowed analysis of low frequency and rare variants in conjunction with common variants, thereby improving the search for functional variants and thus the understanding of the underlying biology of human traits and diseases. Here, we used a large Icelandic whole genome sequence dataset combined with Danish exome sequence data to gain insight into the genetic architecture of serum levels of vitamin B12 (B12) and folate. Up to 22.9 million sequence variants were analyzed in combined samples of 45,576 and 37,341 individuals with serum B12 and folate measurements, respectively. We found six novel loci associating with serum B12 (CD320, TCN2, ABCD4, MMAA, MMACHC) or folate levels (FOLR3) and confirmed seven loci for these traits (TCN1, FUT6, FUT2, CUBN, CLYBL, MUT, MTHFR). Conditional analyses established that four loci contain additional independent signals. Interestingly, 13 of the 18 identified variants were coding and 11 of the 13 target genes have known functions related to B12 and folate pathways. Contrary to epidemiological studies we did not find consistent association of the variants with cardiovascular diseases, cancers or Alzheimer's disease although some variants demonstrated pleiotropic effects. Although to some degree impeded by low statistical power for some of these conditions, these data suggest that sequence variants that contribute to the population diversity in serum B12 or folate levels do not modify the risk of developing these conditions. Yet, the study demonstrates the value of combining whole genome and exome sequencing approaches to ascertain the genetic and molecular architectures underlying quantitative trait associations.
Genome-wide association studies have in recent years revealed a wealth of common variants associated with common diseases and phenotypes. We took advantage of the advances in sequencing technologies to study the association of low frequency and rare variants in conjunction with common variants with serum levels of vitamin B12 (B12) and folate in Icelanders and Danes. We found 18 independent signals in 13 loci associated with serum B12 or folate levels. Interestingly, 13 of the 18 identified variants are coding and 11 of the 13 target genes have known functions related to B12 and folate pathways. These data indicate that the target genes at all of the loci have been identified. Epidemiological studies have shown a relationship between serum B12 and folate levels and the risk of cardiovascular diseases, cancers, and Alzheimer's disease. We investigated association between the identified variants and these diseases but did not find consistent association.
The LIM homeobox containing genes of the LIM-3 group, Lhx3 and Lhx4, are critical for normal development. Both genes are involved in the formation of the pituitary and the motoneuron system and loss of either gene causes perinatal lethality. Previous studies had shown that Lhx3 is overexpressed in hyperplastic placentas of mouse interspecies hybrids. To determine the role of LHX3 in the mouse placenta, we performed expression and function analyses. Our results show that Lhx3 exhibits specific spatial and temporal expression in the mouse placenta, however, deletion of Lhx3 does not produce a placental phenotype. To test whether this is due to functional substitution by Lhx4, we performed a phenotype analysis of Lhx3−/−;Lhx4−/−double-mutant placentas. A subset of Lhx3−/−;Lhx4−/− placentas exhibited abnormal structure of the labyrinth, however, absence of both LIM-3 genes did not interfere with placental transport nor consistently with expression of target genes such as Gnrhr. Thus, LHX3 and LHX4 appear to be dispensable for placental development and function.
LIM-homeobox gene; Lhx3; Lhx4; mouse placenta
The SNRNP200 gene encodes hBrr2, a helicase essential for pre-mRNA splicing. Six mutations in SNRNP200 have recently been discovered to be associated with autosomal dominant retinitis pigmentosa (adRP). In this work, we analyzed a Chinese family with adRP and identified a novel missense mutation in SNRNP200. To identify the genetic defect in this family, exome of the proband was captured and sequencing analysis was performed to exclude known genetic defects and find possible pathogenic mutations. Subsequently, candidate mutations were validated in affected family members using Sanger sequencing. A novel missense mutation, c.2653C>G transition (p.Q885E), in exon 20 of SNRNP200 was identified. The mutation co-segregated with the disease phenotype over four generations and was absent in 100 normal unaffected individuals. This mutation occurs at highly conserved position in hBrr2 and is predicted to have a functional impact, suggesting that hBrr2-dependent small nuclear riboproteins (snRNPs) unwinding and spliceosome activation is important in the pathogenesis of some variants of RP.
AKAP150 knockout- and mutant knock-in alleles reveal an unexpected role of the adaptor in anchoring phosphatase 2B for efficient insulin secretion from pancreatic β-cells and thus glucose homeostasis.
Endocrine release of insulin principally controls glucose homeostasis. Nutrient-induced exocytosis of insulin granules from pancreatic β-cells involves ion channels and mobilization of Ca2+ and cyclic AMP (cAMP) signalling pathways. Whole-animal physiology, islet studies and live-β-cell imaging approaches reveal that ablation of the kinase/phosphatase anchoring protein AKAP150 impairs insulin secretion in mice. Loss of AKAP150 impacts L-type Ca2+ currents, and attenuates cytoplasmic accumulation of Ca2+ and cAMP in β-cells. Yet surprisingly AKAP150 null animals display improved glucose handling and heightened insulin sensitivity in skeletal muscle. More refined analyses of AKAP150 knock-in mice unable to anchor protein kinase A or protein phosphatase 2B uncover an unexpected observation that tethering of phosphatases to a seven-residue sequence of the anchoring protein is the predominant molecular event underlying these metabolic phenotypes. Thus anchored signalling events that facilitate insulin secretion and glucose homeostasis may be set by AKAP150 associated phosphatase activity.
A-kinase anchoring protein (AKAP); calcineurin (PP2B); cyclic-AMP-dependent protein kinase (PKA); glucoregulation; glucose-stimulated insulin secretion (GSIS)
The proteasome is the most complex protease known, with a molecular mass of approximately 3 MDa and 33 distinct subunits. Recent studies reported the discovery of four chaperones that promote the assembly of a 19-subunit subcomplex of the proteasome known as the regulatory particle, or RP. These and other findings define a new and highly unusual macromolecular assembly pathway. The RP mediates substrate selection by the proteasome and injects substrates into the core particle (CP) to be degraded. A heterohexameric ring of ATPases, the Rpt proteins, is critical for RP function. These ATPases abut the CP and their C-terminal tails help to stabilize the RP-CP interface. ATPase heterodimers bound to the chaperone proteins are early intermediates in assembly of the ATPase ring. The four chaperones have the common feature of binding the C-domains of Rpt proteins, apparently a remarkable example of convergent evolution; each chaperone binds a specific Rpt subunit. The C-domains are distinct from the C-terminal tails but proximal to them. Some but probably not all of the RP chaperones appear to compete with CP for binding of the Rpt proteins, as a result of the proximity of the tails to the C-domain. This competition may underlie the release mechanism for these chaperones. Genetic studies in yeast point to the importance of the interaction between the CP and the Rpt tails in assembly, and a recent biochemical study in mammals suggests that RP assembly takes place on pre-assembled CP. These results do not exclude a parallel, CP-independent pathway of assembly. Ongoing work should soon clarify the roles of both the CP and the four chaperones in RP assembly.
proteasome; assembly; regulatory particle; AAA protein; chaperone
Nonsense-mediated mRNA decay (NMD) affects the outcome of alternative splicing by degrading mRNA isoforms with premature termination codons. Splicing regulators constitute important NMD targets; however, the extent to which loss of NMD causes extensive deregulation of alternative splicing has not previously been assayed in a global, unbiased manner. Here, we combine mouse genetics and RNA-seq to provide the first in vivo analysis of the global impact of NMD on splicing patterns in two primary mouse tissues ablated for the NMD factor UPF2.
We developed a bioinformatic pipeline that maps RNA-seq data to a combinatorial exon database, predicts NMD-susceptibility for mRNA isoforms and calculates the distribution of major splice isoform classes. We present a catalog of NMD-regulated alternative splicing events, showing that isoforms of 30% of all expressed genes are upregulated in NMD-deficient cells and that NMD targets all major splicing classes. Importantly, NMD-dependent effects are not restricted to premature termination codon+ isoforms but also involve an abundance of splicing events that do not generate premature termination codons. Supporting their functional importance, the latter events are associated with high intronic conservation.
Our data demonstrate that NMD regulates alternative splicing outcomes through an intricate web of splicing regulators and that its loss leads to the deregulation of a panoply of splicing events, providing novel insights into its role in core- and tissue-specific regulation of gene expression. Thus, our study extends the importance of NMD from an mRNA quality pathway to a regulator of several layers of gene expression.
Hepatocellular carcinoma (HCC) has a dismal 5-year-survival rate of 10%, so
novel strategies are warranted. IL-24 mediates anti-tumor activity reducing
STAT3 expression, which suggests that interferon (IFN) alpha may augment
tumor cell lysis and reduce angiogenesis. We investigated the antitumor
activity of treatment with IFN-α, with the oncolytic adenovirus
SG600-IL-24, or the combination of both in HCC in vitro and in
RT-PCR, ELISA assay and Western-blot confirmed that the exogenous IL-24 gene
was highly expressed in HCC cells infected with SG600-IL-24. Treatment with
combined IFN-α and SG600-IL-24 suppressed growth and promoted apoptosis
of the HepG2, MHCC97L, and HCCLM3 cell lines compared with the normal cell
line L02. The combined therapy increased STAT1 and SOCS1 and apoptosis, but
decreased the expression of the metastatic and angiogenic proteins MMP-2,
XIAP, OPN, and VEGF, which are regulated by STAT3 in HCC cells in
vitro. To assess the effects in vivo, the HCC cell line
HCCLM3 was transplanted subcutaneously into the right flanks of nude mice.
Mice in the IFN-α group, the SG600-IL-24 group, or the combined therapy
group had significantly suppressed growth of the HCC xenografted tumors
compared to the PBS control group of mice. Among the mice treated with the
combination of IFN-α and SG600-IL-24, three of those eight mice had
long-term survival and no evidence of a tumor. These mice also had decreased
expression of the metastatic and angiogenic proteins MMP-2, XIAP, OPN, and
The present study demonstrated for the first time the potential antitumor
activity of IFN-α combined with the oncolytic adenovirus SG600-IL-24 in
HCC both in vitro and in vivo, and suggests its further
development as a potential candidate for HCC cancer gene therapy.
Gene therapy; Hepatocellular carcinoma; Interferon (IFN); Mda-7/IL-24; Nude mice; Oncolytic adenovirus
cAMP is a critical messenger for insulin and glucagon secretion from pancreatic β- and α-cells, respectively. Dispersed β-cells show cAMP oscillations, but the signaling kinetics in cells within intact islets of Langerhans is unknown.
RESEARCH DESIGN AND METHODS
The subplasma-membrane cAMP concentration ([cAMP]pm) was recorded in α- and β-cells in the mantle of intact mouse pancreatic islets using total internal reflection microscopy and a fluorescent translocation biosensor. Cell identification was based on the opposite effects of adrenaline on cAMP in α- and β-cells.
In islets exposed to 3 mmol/L glucose, [cAMP]pm was low and stable. Glucagon and glucagon-like peptide-1(7-36)-amide (GLP-1) induced dose-dependent elevation of [cAMP]pm, often with oscillations synchronized among β-cells. Whereas glucagon also induced [cAMP]pm oscillations in most α-cells, <20% of the α-cells responded to GLP-1. Elevation of the glucose concentration to 11–30 mmol/L in the absence of hormones induced slow [cAMP]pm oscillations in both α- and β-cells. These cAMP oscillations were coordinated with those of the cytoplasmic Ca2+ concentration ([Ca2+]i) in the β-cells but not caused by the changes in [Ca2+]i. The transmembrane adenylyl cyclase (AC) inhibitor 2′5′-dideoxyadenosine suppressed the glucose- and hormone-induced [cAMP]pm elevations, whereas the preferential inhibitors of soluble AC, KH7, and 1,3,5(10)-estratrien-2,3,17-β-triol perturbed cell metabolism and lacked effect, respectively.
Oscillatory [cAMP]pm signaling in secretagogue-stimulated β-cells is maintained within intact islets and depends on transmembrane AC activity. The discovery of glucose- and glucagon-induced [cAMP]pm oscillations in α-cells indicates the involvement of cAMP in the regulation of pulsatile glucagon secretion.
The S. cerevisiae proteasome comprises a 19-subunit regulatory particle (RP) and 28-subunit core particle (CP). To be degraded, substrates must cross the CP-RP interface, a site of complex conformational changes and regulatory events. This interface includes two aligned heteromeric rings: the six ATPase (Rpt) subunits of the RP and the seven α subunits of the CP. Rpt C-termini bind intersubunit cavities of the α ring, thus directing CP gating and proteasome assembly. We used crosslinking to map the Rpt C-termini to the α subunit pockets. This reveals an unexpected asymmetry: one side of the ring shows 1:1 contacts of Rpt2–α4, Rpt6–α3, and Rpt3–α2, whereas, on the opposite side, the Rpt1, Rpt4, and Rpt5 tails each crosslink to multiple α pockets. Rpt-CP crosslinks are all sensitive to nucleotide, implying that ATP hydrolysis drives dynamic alterations at the CP-RP interface.
proteasome; ubiquitin; AAA protein; crosslinking
Aerosol drug delivery during noninvasive ventilation (NIV) is known to be inefficient due to high depositional losses. To improve drug delivery efficiency, the concept of enhanced condensational growth (ECG) was recently proposed in which a submicrometer or nanoaerosol reduces extrathoracic deposition and subsequent droplet size increase promotes lung retention. The objective of this study was to provide proof-of-concept that the ECG approach could improve lung delivery of nasally administered aerosols under conditions consistent with NIV.
Aerosol deposition and size increase were evaluated in an adult nose–mouth–throat (NMT) replica geometry using both in vitro experiments and CFD simulations. For the ECG delivery approach, separate streams of a submicrometer aerosol and warm (39°C) saturated air were generated and delivered to the right and left nostril inlets, respectively. A control case was also considered in which an aerosol with a mass median aerodynamic diameter (MMAD) of 4.67 μm was delivered to the model.
In vitro experiments showed that the ECG approach significantly reduced the drug deposition fraction in the NMT geometry compared with the control case [14.8 (1.83)%—ECG vs. 72.6 (3.7)%—control]. Aerosol size increased from an initial MMAD of 900 nm to a size of approximately 2 μm at the exit of the NMT geometry. Results of the CFD model were generally in good agreement with the experimental findings. Based on CFD predictions, increasing the delivery temperature of the aerosol stream from 21 to 35°C under ECG conditions further reduced the total NMT drug deposition to 5% and maintained aerosol growth by ECG to approximately 2 μm.
Application of the ECG approach may significantly improve the delivery of pharmaceutical aerosols during NIV and may open the door for using the nasal route to routinely deliver pulmonary medications.
respiratory drug delivery; nanoaerosols; hygroscopic droplet growth; high flow therapy; noninvasive positive pressure ventilation; adult nasal–mouth–throat (NMT) model; in vitro deposition experiments; CFD modeling
The objective of this study was to evaluate the delivery of inhaled pharmaceutical aerosols using an enhanced condensational growth (ECG) approach in an airway model extending from the oral cavity to the end of the tracheobronchial (TB) region. The geometry consisted of an elliptical mouth-throat (MT) model, the upper TB airways extending to bifurcation B3, and a subsequent individual path model entering the right lower lobe of the lung. Submicrometer monodisperse aerosols with diameters of 560 and 900 nm were delivered to the mouth inlet under control (25 °C with subsaturated air) or ECG (39 or 42 °C with saturated air) conditions. Flow fields and droplet characteristics were simulated using a computational fluid dynamics model that was previously demonstrated to accurately predict aerosol size growth and deposition. Results indicated that both the control and ECG delivery cases produced very little deposition in the MT and upper TB model (approximately 1%). Under ECG delivery conditions, large size increases of the aerosol droplets were observed resulting in mass median aerodynamic diameters of 2.4–3.3 μm exiting B5. This increase in aerosol size produced an order of magnitude increase in aerosol deposition within the TB airways compared with the controls, with TB deposition efficiencies of approximately 32–46% for ECG conditions. Estimates of downstream pulmonary deposition indicted near full lung retention of the aerosol during ECG delivery. Furthermore, targeting the region of TB deposition by controlling the inlet temperature conditions and initial aerosol size also appeared possible.
Respiratory drug delivery; Nanoaerosols; Hygroscopic droplet growth; CFD modeling; Individual path airway model; Targeted aerosol deposition
Eukaryotic proteasome consists of a core particle (CP), which degrades unfolded protein, and a regulatory particle (RP), which is responsible for recognition, ATP-dependent unfolding and translocation of polyubiquitinated substrate protein. In the archaea Methanocaldococcus jannaschii, the RP is a homohexameric complex of proteasome-activating nucleotidase (PAN). Here we report the crystal structures of essential elements of the archaeal proteasome: the CP, the ATPase domain of PAN, and a distal subcomplex that is likely the first to encounter substrate. The distal subcomplex contains a coiled-coil segment and an OB-fold domain, both of which appear to be conserved in the eukaryotic proteasome. The OB domains of PAN form a hexameric ring with a 13-Å pore, which likely constitutes the outermost constriction of the substrate translocation channel. These studies reveal structural codes and architecture of the complete proteasome, identify potential substrate-binding sites, and uncover unexpected asymmetry in the RP of archaea and eukaryotes.