Homer1 knockdown protects dopamine neurons through regulating calcium homeostasis in an in vitro model of Parkinson's disease

Homer1 protein is an important scaffold protein at postsynaptic density and has been demonstrated to play a central role in calcium signaling in the central nervous system. The aim of this study was to investigate the effects of Homer1 knockdown on MPP⁺ induced neuronal injury in cultured dopamine (DA) neurons. We found that down-regulating Homer1 expression with specific small interfering RNA (siRNA) significantly suppressed LDH release, reduced Propidium iodide (PI) or Hoechst staining, increased the number of tyrosine hydroxylase (TH) positive cells and DA uptake, and attenuated apoptotic and necrotic cell death after MPP⁺ injury. Homer1 knockdown decreased intracellular reactive oxygen species (ROS) generation through inhibition of intracellular calcium overload, but did not affect the endogenous antioxidant enzyme activities. Calcium imaging was used to examine the changes of intracellular Ca^2 + concentration ([Ca^2 +]_cyt) and Ca^2 + in endoplasmic reticulum (ER) ([Ca^2 +]_ER), and the results showed that Homer1 siRNA transfection attenuated ER Ca^2 + release up to 120 min after MPP⁺ injury. Furthermore, decrease of [Ca^2 +]_cyt induced by Homer1 knockdown in MPP⁺ treated neurons was further enhanced by NMDA receptor antagonists MK-801 and AP-5, but not canonical transient receptor potential (TRPC) channel antagonist SKF-96365. l-type calcium antagonist isradipine but not nimodipine further inhibited intracellular calcium overload after MPP⁺ insult in Homer1 down-regulated neurons. These results suggest that Homer1 knockdown has protective effects against neuronal injury in in vitro PD model by reducing calcium overload mediated ROS generation, and this protection may be dependent at least in part on the regulatory effects on the function of calcium channels in both plasma membrane and ER.     

Evaluation of adsorbents for separation and purification of paclitaxel from plant cell cultures

In this study, we evaluated the efficiency of different adsorbents for the removal of plant-derived impurities during the pre-purification of paclitaxel from plant cell cultures. Using the synthetic adsorbents sylopute and active clay and their major components SiO₂ and MgO, we performed adsorbent treatment and analyzed the paclitaxel precipitates recovered from hexane precipitation. When SiO₂ was used, the highest purity (～58.1%) and yield (～91.5%) of paclitaxel were obtained. We also determined differences in the effectiveness of the adsorbent treatment according to changes in the surface area, pore volume and pore diameter of SiO₂. Adsorbent treatment was more effective when pore diameter was larger (silica I [2.19 nm] < silica II [4.92 nm] < silica III [9.07 nm]). The highest purity (～74.3%) and yield (～92.9%) of paclitaxel were obtained when silica III was used in the adsorbent treatment. Pore diameter had a greater effect on the removal of plant-derived impurities during the pre-purification of paclitaxel compared with surface area and pore volume. This result could be confirmed by HPLC analysis of the absorbent after treatment and TGA of the organic substances that were bonded to the adsorbent.     

Photobiomodulation of human adipose-derived stem cells using 810 nm and 980 nm lasers operates via different mechanisms of action

Photobiomodulation (PBM) using red or near-infrared (NIR) light has been used to stimulate the proliferation and differentiation of adipose-derived stem cells. The use of NIR wavelengths such as 810 nm is reasonably well accepted to stimulate mitochondrial activity and ATP production via absorption of photons by cytochrome c oxidase. However, the mechanism of action of 980 nm is less well understood. Here we study the effects of both wavelengths (810 nm and 980 nm) on adipose-derived stem cells in vitro. Both wavelengths showed a biphasic dose response, but 810 nm had a peak dose response at 3 J/cm² for stimulation of proliferation at 24 h, while the peak dose for 980 nm was 10–100 times lower at 0.03 or 0.3 J/cm². Moreover, 980 nm (but not 810 nm) increased cytosolic calcium while decreasing mitochondrial calcium. The effects of 980 nm could be blocked by calcium channel blockers (capsazepine for TRPV1 and SKF96365 for TRPC channels), which had no effect on 810 nm. To test the hypothesis that the chromophore for 980 nm was intracellular water, which could possibly form a microscopic temperature gradient upon laser irradiation, we added cold medium (4 °C) during the light exposure, or pre-incubated the cells at 42 °C, both of which abrogated the effect of 980 nm but not 810 nm. We conclude that 980 nm affects temperature-gated calcium ion channels, while 810 nm largely affects mitochondrial cytochrome c oxidase.     

Stress-induced dissociations between intracellular calcium signaling and insulin secretion in pancreatic islets

In healthy pancreatic islets, glucose-stimulated changes in intracellular calcium ([Ca²⁺]_i) provide a reasonable reflection of the patterns and relative amounts of insulin secretion. We report that [Ca²⁺]_i in islets under stress, however, dissociates with insulin release in different ways for different stressors. Islets were exposed for 48 h to a variety of stressors: cytokines (low-grade inflammation), 28 mM glucose (28G, glucotoxicity), free fatty acids (FFAs, lipotoxicity), thapsigargin (ER stress), or rotenone (mitochondrial stress). We then measured [Ca²⁺]_i and insulin release in parallel studies. Islets exposed to all stressors except rotenone displayed significantly elevated [Ca²⁺]_i in low glucose, however, increased insulin secretion was only observed for 28G due to increased nifedipine-sensitive calcium-channel flux. Following 3–11 mM glucose stimulation, all stressors substantially reduced the peak glucose-stimulated [Ca²⁺]_i response (first phase). Thapsigargin and cytokines also substantially impacted aspects of calcium influx and ER calcium handling. Stressors did not significantly impact insulin secretion in 11 mM glucose for any stressor, although FFAs showed a borderline reduction, which contributed to a significant decrease in the stimulation index (11:3 mM glucose) observed for FFAs and also for 28G. We also clamped [Ca²⁺]_i using 30 mM KCl + 250 μM diazoxide to test the amplifying pathway. Only rotenone-treated islets showed a robust increase in 3–11 mM glucose-stimulated insulin secretion under clamped conditions, suggesting that low-level mitochondrial stress might activate the metabolic amplifying pathway. We conclude that different stressors dissociate [Ca²⁺]_i from insulin secretion differently: ER stressors (thapsigargin, cytokines) primarily affect [Ca²⁺]_i but not conventional insulin secretion and ‘metabolic’ stressors (FFAs, 28G, rotenone) impacted insulin secretion.     

Size exclusion chromatography of zein and xanthophylls: Optimization of operating parameters

Ethanol-soluble components of corn (zein and xanthophylls) were separated and purified by size exclusion chromatography. Aqueous ethanol was used as the solvent for the entire process from extraction through chromatography. The effect of operating and design parameters, such as temperature, flow rate, loading mass, loading volume, column height and diameter, on productivity and resolution of the components was studied. Using a one-variable-at-a-time (OVAT) approach with 1 cm × 60 cm columns, optimum conditions were determined to be 40 °C temperature, 0.25 mL/min flow rate, volume loading of 22 mL corn extract, mass loading at 70 g/L of corn extract. All components could be resolved with base line separation with a 240 cm column length. Column diameter did not affect separation, implying linear scalability with constant flow distribution.     

Fungal surface protein mediated one-pot synthesis of stable and hemocompatible gold nanoparticles

Despite their large secretome and wide applications in bioprocesses, fungi remain underexplored in metal nanoparticles (MNP) biosynthesis. Previous studies have shown that cell surface proteins of Rhizopus oryzae play a crucial role in biomineralization of Au(III) to produce gold nanoparticles (AuNPs). Therefore, it is hypothesized that purified cell surface protein may produce in vitro AuNPs with narrow size distribution for biomedical and biocatalytic applications. However, different protein extraction methods might affect protein stability and the AuNP biosynthesis process. Herein, we have explored the extraction of cell surface proteins from R. oryzae using common detergents and reducing agent (sodium dodecyl sulfate (SDS) Triton X-100, and 1,4-dithiothreitol (DTT)) and their effect on the size and shape of the biosynthetic AuNPs. The surface proteins extracted with reducing agent (DTT) and non-ionic detergent (Triton X-100) produce spherical AuNPs with a mean particle size of 16 ± 7 nm, and 19 ± 4 nm, respectively, while the AuNPs produced by the surface protein extracted by ionic detergent (SDS) are flower-like AuNPs with broader size distribution of 43 ± 19 nm. This synthetic approach does not require use of any harsh chemicals, multistep preparation and separation process, favouring environmental sustainability. The biosynthetic AuNPs thus formed, are stable in different physiological buffers and hemocompatible, making them suitable for biomedical applications.     

Particle retention in suspension-feeding fish after removal of filtration structures

The suspension-feeding cichlids Oreochromis aureus (blue tilapia) and Oreochromis esculentus (ngege tilapia) are able to selectively retain small food particles. The gill rakers and microbranchiospines of these species have been assumed to function as filters. However, surgical removal of these oral structures, which also removed associated mucus, did not significantly affect the total number of 11–200 μm particles ingested by the fish. This result supports the hypothesis that the branchial arch surfaces themselves play an important role in crossflow filtration. Both species selectively retained microspheres greater than 50 μm with gill rakers and microbranchiospines intact as well as removed, demonstrating that neither these structures nor mucus are necessary for size selectivity to occur during biological crossflow filtration. After removal of the gill rakers and microbranchiospines, O. esculentus retained significantly more microspheres 51–70 μm in diameter and fewer 91–130 μm microspheres compared to retention with intact structures, but the particle size selectivity of O. aureus was not affected significantly. These results support conclusions from previous computational fluid dynamics simulations indicating that particle size can have marked effects on particle trajectory and retention inside the fish oropharyngeal cavity during crossflow filtration. The substantial inter-individual variability in particle retention by suspension-feeding fish is an unexplored area of research with the potential to increase our understanding of the factors influencing particle retention during biological filtration.     

Sono-chemical preparation of cellulose nanocrystals from lignocellulose derived materials

This study examined the production of cellulose nanocrystals from microcrystalline wood cellulose, Avicel and recycled pulp of wood pulp using sono-chemical-assisted hydrolysis. Two hydrolysis systems: deionized water and maleic acid were evaluated. In deionized water, Avicel produced cellulose nanocrystals with average diameter of 21 ± 5 nm (minimum 15 nm and maximum 32 nm). Cellulose nanocrystals from recycled pulp were not distinctively spherical and had an average diameter of 23 ± 4 nm (minimum 14 nm and maximum 32 nm). Maleic acid (50 mM) sono-chemical assisted hydrolysis of Avicel at 15 °C and 90% power output for 9 min produced cellulose nanocrystals which were cylindrical in shape and were of dimensions, length 65 ± 19 nm and width 15 nm.     

Enhanced parkin levels favor ER-mitochondria crosstalk and guarantee Ca2 + transfer to sustain cell bioenergetics

Loss-of-function mutations in PINK1 or parkin genes are associated with juvenile-onset autosomal recessive forms of Parkinson disease. Numerous studies have established that PINK1 and parkin participate in a common mitochondrial-quality control pathway, promoting the selective degradation of dysfunctional mitochondria by mitophagy. Upregulation of parkin mRNA and protein levels has been proposed as protective mechanism against mitochondrial and endoplasmic reticulum (ER) stress. To better understand how parkin could exert protective function we considered the possibility that it could modulate the ER–mitochondria inter-organelles cross talk. To verify this hypothesis we investigated the effects of parkin overexpression on ER–mitochondria crosstalk with respect to the regulation of two key cellular parameters: Ca^2 + homeostasis and ATP production. Our results indicate that parkin overexpression in model cells physically and functionally enhanced ER–mitochondria coupling, favored Ca^2 + transfer from the ER to the mitochondria following cells stimulation with an 1,4,5 inositol trisphosphate (InsP₃) generating agonist and increased the agonist-induced ATP production. The overexpression of a parkin mutant lacking the first 79 residues (ΔUbl) failed to enhance the mitochondrial Ca^2 + transients, thus highlighting the importance of the N-terminal ubiquitin like domain for the observed phenotype. siRNA-mediated parkin silencing caused mitochondrial fragmentation, impaired mitochondrial Ca^2 + handling and reduced the ER–mitochondria tethering. These data support a novel role for parkin in the regulation of mitochondrial homeostasis, Ca^2 + signaling and energy metabolism under physiological conditions.     

Depot-specific modulation of adipokine levels in rat adipose tissue by diet-induced obesity: The effect of aerobic training and energy restriction

The present study examined the effects of aerobic training and energy restriction on adipokines levels in mesenteric (MEAT) and retroperitoneal (RPAT) white adipose tissue from obese rats. Male Wistar rats were fed with standard laboratory diet (Control group) or high fat diet (HFD). After 15 weeks, HFD rats were randomly assigned to the following groups: rats submitted to HFD, which were sedentary (sedentary HFD, n = 8) or trained (trained HFD, n = 8); or submitted to energy-restriction (ER), which were sedentary (sedentary ER, n = 8) or trained (trained ER, n = 8). Trained rats ran on a treadmill at 55% VO_2max for 60 min/day, 5 days/week, for 10 weeks. ER rats were submitted to a reduction of 20% daily caloric ingestion compared to the Control group. ER and aerobic training decreased body weight, MEAT and RPAT absolute weight, and fat mass. IL-6, IL-10 and TNF-α levels were decreased and adiponectin did not change in RPAT in response to ER protocol. On the other hand, ER and the aerobic training protocol decreased IL-6, TNF-α and adiponectin levels in MEAT. Absolute MEAT weight showed a positive correlation with IL-6 (r = 0.464), TNF-α (r = 0.508); and adiponectin (r = 0.342). These results suggest a tissue-specific heterogeneous response in adipokines level. The combination of the protocols (aerobic training and energy restriction) did not induce an enhanced effect.     

Highly efficient covalent immobilization of catalase on titanate nanotubes

In this study, titanate nanotubes (TNTs) with desirable biocompatibility and hydrophilicity have been synthesized by a facile and cost-effective alkaline hydrothermal method, and used to immobilize the enzyme. The characterization results reveal that the prepared TNTs have a regular tubular morphology with a length about 100–180 nm and an outer diameter about 10 nm, and a BET specific surface area of 305.4 m² g⁻¹. Catalase (CAT), as the model enzyme, was pre-modified by 3-(3,4-dihydroxyphenyl) propionic acid (3,4-diHPP) via 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) coupling chemistry, and then covalently immobilized on the TNTs surface by the chelation of catechol groups with Ti⁴⁺ ions. It is found that TNTs exhibits excellent performances as the immobilized supporter of enzyme: the enzyme loading is as high as 820 mg g of support⁻¹; the relative activity of immobilized enzyme is about 60% of that of free enzyme; the immobilized CAT demonstrates enhanced storage and recycling stability.     

Calcareous sponge biomineralization: Ultrastructural and compositional heterogeneity of spicules in Leuconia johnstoni

In contrast to siliceous sponge spicules, the biomineralization in calcareous sponges is poorly understood. In particular, the existence of a differentiated central core in calcareous spicules is still controversial. Here we combine high-spatial resolution analyses, including NanoSIMS, Raman, SXM, AFM, SEM and TEM to investigate the composition, mineralogy and ultrastructure of the giant tetractines of Leuconia johnstoni Carter, 1871 (Baeriidae, Calcaronea) and the organization of surrounding cells. A compositionally distinct core is present in these spicule types. The core measures 3.5–10 μm in diameter and is significantly depleted in Mg and lightly enriched in S compared with the adjacent outer layer in the spicule. Measured Mg/Ca ratios in the core range from 70 to 90 mmol/mol compared to 125–130 mmol/mol in the adjacent calcite envelope. However, this heterogeneous distribution of Mg and S is not reflected in the mineralogy and the microstructure. Raman spectroscopy demonstrates a purely calcitic mineralogy. SEM examination of slightly etched spicules indicates an ultrastructure organized hierarchically in a concentric pattern, with layers less than 250 nm in width inside layers averaging 535 ± 260 nm. No change in structural pattern corresponds to the Mg/Ca variation observed. AFM and TEM observations show a nanogranular organization of the spicules with a network of intraspicular organic material intercalated between nanograins 60–130 nm in diameter. Observations of sclerocyte cells in the process of spiculogenesis suggest that the compositionally distinct core is produced by a sub-apical sclerocyte “founder cell” that controls axial growth, while the envelope is secreted by lateral sclerocytes “thickener cells”, which control radial growth.     

The gene transfer agent-like particle of the marine phototrophic bacterium Rhodovulum sulfidophilum

Gene transfer agents (GTAs) are shaped like bacteriophage particles but have many properties that distinguish them from bacteriophages. GTAs play a role in horizontal gene transfer in nature and thus affect the evolution of prokaryotic genomes. In the course of studies on the extracellular production of designed RNAs using the marine bacterium Rhodovulum sulfidophilum, we found that this bacterium produces a GTA-like particle. The particle contains DNA fragments of 4.5 kb, which consist of randomly fragmented genomic DNA from the bacterium. This 4.5-kb DNA production was prevented while quorum sensing was inhibited. Direct observation of the particle by transmission electron microscopy revealed that the particle resembles a tailed phage and has a head diameter of about 40 nm and a tail length of about 60 nm. We also identified the structural genes for the GTA in the genome. Translated amino acid sequences and gene positions are closely related to those of the genes that encode the Rhodobacter capsulatus GTA. This is the first report of a GTA-like particle from the genus Rhodovulum. However, gene transfer activity of this particle has not yet been confirmed. The differences between this particle and other GTAs are discussed.     

Biodegradable and biocompatible multi-arm star amphiphilic block copolymer as a carrier for hydrophobic drug delivery

Multi-arm star amphiphilic block copolymers (SABCs) with approximately 32 arms were synthesized and characterized for drug delivery applications. A hyperbranched polyester, boltorn^® H40 (H40), was used as the macroinitiator for the ring-opening polymerization of ?-caprolactone (?-CL). The resulting multi-arm H40-poly(?-caprolactone) (H40-PCL-OH) was further reacted with carboxyl terminated methoxy poly(ethylene glycol) (MPEG-COOH) to form H40-PCL-b-MPEG copolymers. The resulting SABCs were characterized by ¹H NMR spectroscopy and gel permeation chromatography (GPC). The critical aggregation concentration (CAC) of H40-PCL-b-MPEG was 3.8 mg/L as determined by fluorescence spectrophotometry. Below the CAC, stable unimolecular micelles were formed with an average diameter of 18 nm as measured by TEM. Above the CAC, unimolecular micelles exhibited agglomeration with an average diameter of 98 nm. The hydrodynamic diameter of these agglomerates was found to be 122 nm, as measured by dynamic light scattering (DLS). The drug loading efficacy of the H40-PCL-b-MPEG micelles was 26 wt%. Drug release study showed an initial burst followed by a sustained release of the entrapped hydrophobic model drug, 5-fluorouracil, over a period of 9–140 h. These results indicate that the H40-PCL-b-MPEG micelles have great potential as hydrophobic drug delivery carriers.     

Bacterial cell-surface displaying of thermo-tolerant glutamate dehydrogenase and its application in l-glutamate assay

In this paper, glutamate dehydrogenase (Gldh) is reported to efficiently display on Escherichia coli cell surface by using N-terminal region of ice the nucleation protein as an anchoring motif. The presence of Gldh was confirmed by SDS-PAGE and enzyme activity assay. Gldh was detected mainly in the outer membrane fraction, suggesting that the Gldh was displayed on the bacterial cell surface. The optimal temperature and pH for the bacteria cell-surface displayed Gldh (bacteria-Gldh) were 70 °C and 9.0, respectively. Additionally, the fusion protein retained almost 100% of its initial enzymatic activity after 1 month incubation at 4 °C. Transition metal ions could inhibit the enzyme activity to different extents, while common anions had little adverse effect on enzyme activity. Importantly, the displayed Gldh is most specific to l-glutamate reported so far. The bacterial Gldh was enabled to catalyze oxidization of l-glutamate with NADP⁺ as cofactor, and the resultant NADPH can be detected spectrometrically at 340 nm. The bacterial-Gldh based l-glutamate assay was established, where the absorbance at 340 nm increased linearly with the increasing l-glutamate concentration within the range of 10 − 400 μM. Further, the proposed approach was successfully applied to measure l-glutamate in real samples.     

Synthesis and characterization of pHLIP® coated gold nanoparticles

Novel approaches in synthesis of spherical and multispiked gold nanoparticles coated with polyethylene glycol (PEG) and pH Low Insertion Peptide (pHLIP^®) were introduced. The presence of a tumor-targeting pHLIP^® peptide in the nanoparticle coating enhances the stability of particles in solution and promotes a pH-dependent cellular uptake. The spherical particles were prepared with sodium citrate as a gold reducing agent to form particles of 7.0±2.5 nm in mean metallic core diameter and ～43 nm in mean hydrodynamic diameter. The particles that were injected into tumors in mice (21 µg of gold) were homogeneously distributed within a tumor mass with no staining of the muscle tissue adjacent to the tumor. Up to 30% of the injected gold dose remained within the tumor one hour post-injection. The multispiked gold nanoparticles with a mean metallic core diameter of 146.0±50.4 nm and a mean hydrodynamic size of ~161 nm were prepared using ascorbic acid as a reducing agent and disk-like bicelles as a template. Only the presence of a soft template, like bicelles, ensured the appearance of spiked nanoparticles with resonance in the near infrared region. The irradiation of spiked gold nanoparticles by an 805 nm laser led to the time- and concentration-dependent increase of temperature. Both pHLIP^® and PEG coated gold spherical and multispiked nanoparticles might find application in radiation and thermal therapies of tumors.     

Effect of glucosamine and related compounds on the degranulation of mast cells and ear swelling induced by dinitrofluorobenzene in mice

AimsGlucosamine has been used safely to relieve osteoarthritis in humans, but the precise mechanism underlying its efficacy is still unclear. In this study, we investigated the direct effects of glucosamine and related compounds on mast cell mediated inflammation using cultured mast cells and an animal model.Main methodsDinitrophenyl (DNP)-IgE-sensitized rat basophilic leukemia RBL-2H3 cells were treated with glucosamine-HCl (GlcN-HCl), N-acetylglucosamine (GlcNAc), chitin oligomer or chitosan oligomer. Cells were stimulated by DNP-BSA to induce degranulation and released β-hexosaminedase was determined colorimetrically to measure the degree of degranulation. Dinitrofluorobenzene (DNFB) sensitized BALB/c mice were administrated orally with 1 or 0.1 mg GlcN-HCl or GlcNAc for 6 days. One hour after the final administration, mice were challenged by DNFB to induce ear swelling.Key findingsGlcN-HCl significantly inhibited the antigen-induced degranulation of RBL-2H3 cells at higher than 0.01 mg/mL for 24 h-treatment while GlcNAc, a chitin oligomer and a chitosan oligomer had no effect. GlcN-HCl also suppressed intracellular calcium mobilization. GlcN-HCl and GlcNAc significantly suppressed the antigen-induced up-regulation of TNF-α and IL-6 mRNA. Ear swelling and histamine levels of plasma and ear in DNFB-treated mice were significantly suppressed by oral administration of GlcN-HCl or GlcNAc (0.1 and 1 mg) for 6 days.SignificanceOur results strongly suggest that GlcN-HCl and GlcNAc have anti-inflammatory effects in vivo by suppressing the activation of mast cells.     

Impact of estrogen receptor alpha and beta agonists on delayed alternation in middle-aged rats

Estrogens act in the adult brain to modulate cognition, enhancing performance on some learning tests and impairing performance on others. Our previous research has revealed an impairing effect of chronic 17β-estradiol treatment in young and aged rats on a prefrontally-mediated working memory task, delayed spatial alternation (DSA). Little is known about the mechanisms of these impairing effects. The current study examined the effects of selective estrogen receptor (ER) α or ERβ activation on DSA performance in middle-aged female rats. Ovariectomized 12 month old Long–Evans (LE) rats were treated by subcutaneous injection with the ERα agonist propyl pyrazole triol (PPT) or the ERβ agonist diarylpropionitrile (DPN) at 0.02, 0.08, or 0.20 mg/kg/day, or with oil vehicle and tested on an operant variable delay DSA task. A 17β-estradiol group (10% in cholesterol) was included as a positive control group. We replicated our previous finding of a 17β-estradiol induced deficit on DSA performance and this effect was paralleled by low dose (0.02 mg/kg/day) DPN treatment. Higher doses of DPN failed to produce a significant change in performance. The highest dose of PPT (0.20 mg/kg/day) also impaired performance, but this effect was subtle and limited to the longest delay during the final block of testing. These data confirm our earlier findings that chronic 17β-estradiol treatment has an impairing effect on the DSA task, and suggest that ERβ activation may underlie the deficit.     

The structure of a COPII tubule

Nearly a third of all eukaryotic proteins are transported from the ER to the Golgi apparatus through the secretory pathway using COPII coated vesicles. Evidence suggests that this transport occurs via 500–900 Å vesicles that bud from the ER membrane. It has been shown that procollagen molecules utilize the COPII proteins for transport, but it is unclear how the COPII coat can accommodate these ～3000 Å long molecules. We now present a cryogenic electron tomographic reconstruction of a Sec13/31 tubule that is approximately 3300 Å long containing a hollow cylindrical interior that is 300 Å in diameter, dimensions that are consistent with those that are required to encapsulate a procollagen molecule wrapped in a membrane and accessory COPII components. This structure suggests a novel mechanism that the COPII coat may employ to transport elongated cargo.     

Disparities in the risk of the ER/PR/HER2 breast cancer subtypes among Asian Americans in California

BackgroundPopulation-based studies of breast cancer often aggregate all Asians into a single category termed Asian/Pacific Islander (API).Purpose(1) Describe the demographic and clinicopathologic features of early breast cancer utilizing all eight ER/PR/HER2 subtypes among white, black, Hispanic, American Indian, seven Asian ethnicities, and the aggregate API category; (2) ascertain the risk of the ER+/PR+/HER2+, ER−/PR−/HER2−, and ER−/PR−/HER2+ subtypes when compared with the ER+/PR+/HER2− subtype, among seven Asian ethnicities versus non-Hispanic white women and (3) contrast the results with the risk of these same subtypes when using the aggregate API category.MethodsUsing the California Cancer Registry, we identified 225,441 cases of stages 1–4 first primary female invasive breast cancer. Logistic regression was used to assess the association of race with the ER+/PR+/HER2+, ER−/PR−/HER2− (triple-negative), and the ER−/PR−/HER2+ subtypes versus the ER+/PR+/HER2− when adjusted for stage, age, tumor grade, and socioeconomic status. Models were fit separately for each subtype. Odds ratios for the seven Asian ethnicities and the aggregate API category using non-Hispanic white women as the reference category were computed.ResultsThere was an increased risk of the ER+/PR+/HER2+ subtype for the combined API category (OR = 1.16; 95% CI = 1.09–1.23). But only Southeast Asians (OR = 1.17; 95% CI = 1.04–1.31), Filipino (OR = 1.23; 95% CI = 1.12–1.36), and Korean (OR = 1.63; 95% CI = 1.38–1.99) women had an increased risk of this subtype. The reduced risk of the triple-negative subtype seen in APIs (OR = 0.84; 95% CI = 0.79–0.90) was only noted in Chinese (OR = 0.80; 95% CI = 0.70–0.91) and Filipino (OR = 0.65; 95% CI = 0.58–0.73) women whereas Indian Continent (OR = 1.25; 95% CI = 1.01–1.53) women had an increased risk of the triple-negative subtype.The race × stage interaction was statistically significant for the ER−/PR−/HER2+ subtype (p < 0.05). When stratified by stage, there was no statistically significant association of race with subtype in stages 3 and 4. APIs had an increased risk of the ER−/PR−/HER2+ subtype in stage 1 (OR = 1.59; 95% CI = 1.37–1.75) and stage 2 (OR = 1.42; 95% CI = 1.28–1.58) but this risk was not seen in Pacific Islander, Indian Continent, and Japanese women for either stage.ConclusionsAmong the Asian ethnicities, there is marked variability in the demographic and clinicopathologic features of breast cancer. Use of the ER/PR/HER2 subtypes reveals that the risk of the ER−/PR−/HER2−, ER+/PR+/HER2+, and ER−/PR−/HER2+ subtypes varies among the Asian population. The API category, is sometimes, but not always reflective of all Asian women.