Lactobacillus acidophilus and Bacillus subtilis significantly change the growth performance, serum immunity and cecal microbiota of Cherry Valley ducks during the fattening period.

This study explored the effects of a Bacillus subtilis and Lactobacillus acidophilus mixture containing the co-fermented products of the two probiotics on growth performance, serum immunity and cecal microbiota of Cherry Valley ducks. This study included 480 one-day-old Cherry Valley ducks divided into four feeding groups: basal diet (control group) and basal diet supplemented with 300, 500, or 700 mg/kg of the probiotic powder; the ducks were raised for 42 days. Compared with the control group, body weight on day 42 and the average daily gain on days 15-42 significantly increased (p < 0.05), and the feed conversion rate significantly decreased (p < 0.05) in the experimental groups. Furthermore, the serum immunoglobulin (Ig) A, IgG, IgM, and interleukin (IL)-4 levels increased significantly (p < 0.05), and IL-1ß, IL-2, and tumor necrosis factor-α decreased significantly (p < 0.05) in the experimental groups. Finally, Sellimonas, Prevotellaceae NK3B31 group, Lachnospiraceae NK4A136 group and Butyricoccus played an important role in the cecal microbiota of the experimental group. Thus, the probiotic powder has impacts on the growth performance, serum immunity and cecal microbiota of Cherry Valley Ducks.

Potential Neuroimmune Interaction in Chronic Pain: A Review on Immune Cells in Peripheral and Central Sensitization.

Chronic pain is a long-standing unpleasant sensory and emotional feeling that has a tremendous impact on the physiological functions of the body, manifesting itself as a dysfunction of the nervous system, which can occur with peripheral and central sensitization. Many recent studies have shown that a variety of common immune cells in the immune system are involved in chronic pain by acting on the peripheral or central nervous system, especially in the autoimmune diseases. This article reviews the mechanisms of regulation of the sensory nervous system by neutrophils, macrophages, mast cells, B cells, T cells, and central glial cells. In addition, we discuss in more detail the influence of each immune cell on the initiation, maintenance, and resolution of chronic pain. Neutrophils, macrophages, and mast cells as intrinsic immune cells can induce the transition from acute to chronic pain and its maintenance; B cells and T cells as adaptive immune cells are mainly involved in the initiation of chronic pain, and T cells also contribute to the resolution of it; the role of glial cells in the nervous system can be extended to the beginning and end of chronic pain. This article aims to promote the understanding of the neuroimmune mechanisms of chronic pain, and to provide new therapeutic ideas and strategies for the control of chronic pain at the immune cellular level.

Recapitulation of endogenous 4R tau expression and formation of insoluble tau in directly reprogrammed human neurons.

Tau is a microtubule-binding protein expressed in neurons, and the equal ratios between 4-repeat (4R) and 3-repeat (3R) isoforms are maintained in normal adult brain function. Dysregulation of 3R:4R ratio causes tauopathy, and human neurons that recapitulate tau isoforms in health and disease will provide a platform for elucidating pathogenic processes involving tau pathology. We carried out extensive characterizations of tau isoforms expressed in human neurons derived by microRNA-induced neuronal reprogramming of adult fibroblasts. Transcript and protein analyses showed that miR neurons expressed all six isoforms with the 3R:4R isoform ratio equivalent to that detected in human adult brains. Also, miR neurons derived from familial tauopathy patients with a 3R:4R ratio altering mutation showed increased 4R tau and the formation of insoluble tau with seeding activity. Our results collectively demonstrate the utility of miRNA-induced neuronal reprogramming to recapitulate endogenous tau regulation comparable with the adult brain in health and disease.

Quantitative proteomic analysis of the effects of dietary deprivation of methionine and cystine on A549 xenograft and A549 xenograft-bearing mouse.

Methionine (Met) and cystine (CySS) are key sulfur donors in cell metabolism and are important nutrients for sustaining tumor growth; however, the molecular effects associated with their deprivation remain to be characterized. Here, we applied a xenograft mouse model to assess the impact of their deprivation on A549 xenografts and the xenograft-bearing animal. Results show that Met and CySS deprivation inhibits A549 growth in vitro, not in vivo. Deprivation was detrimental to the xenograft-bearing mouse, as demonstrated by weight loss and renal dysfunction. Differentially expressed proteins in A549 xenograft and mouse kidneys were characterized using quantitative proteomics. Functional annotation and protein-protein interaction network analysis revealed the enriched signaling pathways, including focal adhesion (Fn1) in the A549 xenograft, and xenobiotic metabolism (Cyp2e1) and glutathione metabolism (Ggt1) in the mouse kidney. Met and CySS deprivation inhibits the migratory and invasive properties of cancer cells, as evidenced by reduced expression of the epithelial to mesenchymal transition marker N-cadherin in A549 cells in vitro. Moreover, IGFBP1 protein expression was inhibited in both A549 xenograft and mouse kidneys. This study provides the first insights into changes within the proteome profile and biological processes upon Met and CySS deprivation in a A549 xenograft mouse model.

Challenging Proteostasis: Role of the Chaperone Network to Control Aggregation-Prone Proteins in Human Disease.

Protein homeostasis (Proteostasis) is essential for correct and efficient protein function within the living cell. Among the critical components of the Proteostasis Network (PN) are molecular chaperones that serve widely in protein biogenesis under physiological conditions, and prevent protein misfolding and aggregation enhanced by conditions of cellular stress. For Alzheimer's, Parkinson's, Huntington's diseases and ALS, multiple classes of molecular chaperones interact with the highly aggregation-prone proteins amyloid-ß, tau, α-synuclein, huntingtin and SOD1 to influence the course of proteotoxicity associated with these neurodegenerative diseases. Accordingly, overexpression of molecular chaperones and induction of the heat shock response have been shown to be protective in a wide range of animal models of these diseases. In contrast, for cancer cells the upregulation of chaperones has the undesirable effect of promoting cellular survival and tumor growth by stabilizing mutant oncoproteins. In both situations, physiological levels of molecular chaperones eventually become functionally compromised by the persistence of misfolded substrates, leading to a decline in global protein homeostasis and the dysregulation of diverse cellular pathways. The phenomenon of chaperone competition may underlie the broad pathology observed in aging and neurodegenerative diseases, and restoration of physiological protein homeostasis may be a suitable therapeutic avenue for neurodegeneration as well as for cancer.

Tau protein aggregates inhibit the protein-folding and vesicular trafficking arms of the cellular proteostasis network.

Tauopathies are a diverse class of neurodegenerative diseases characterized by the formation of insoluble tau aggregates and the loss of cellular function and neuronal death. Tau inclusions have been shown to contain a number of proteins, including molecular chaperones, but the consequences of these entrapments are not well established. Here, using a human cell system for seeding-dependent tau aggregation, we demonstrate that the molecular chaperones heat-shock cognate 71-kDa protein (HSC70)/heat-shock protein 70 (HSP70), HSP90, and J-domain co-chaperones are sequestered by tau aggregates. By employing single-cell analysis of protein-folding and clathrin-mediated endocytosis, we show that both chaperone-dependent cellular activities are significantly impaired by tau aggregation and can be reversed by treatment with small-molecule regulators of heat-shock transcription factor 1 (HSF1) proteostasis that induce the expression of cytosolic chaperones. These results reveal that the sequestration of cytoplasmic molecular chaperones by tau aggregates interferes with two arms of the proteostasis network, likely having profound negative consequences for cellular function.

mPEG-PLA/TPGS mixed micelles via intranasal administration improved the bioavailability of lamotrigine in the hippocampus.

PURPOSE: This study aimed to develop a novel methoxy poly(ethylene glycol)-poly(lactide) (mPEG-PLA)/D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) mixed micelle drug delivery system to improve lamotrigine (LTG) distribution in the hippocampus. METHODS: LTG-loaded mPEG-PLA/TPGS mixed micelles and LTG-loaded mPEG-PLA micelles were formulated, and their characteristics, particle size, surface morphology, and release behavior in vitro were researched. Then, a microdialysis sampling technique coupled with two validated chromatographic systems was developed for the continuous measurement of the protein-unbound form of LTG in the rat plasma and hippocampus after administering two kinds of micelles and LTG solution intranasally. RESULTS: The drug loading and mean size of LTG-loaded micelles and LTG-loaded mixed micelles prepared with optimal formulation were 36.44%±0.14%, 39.28%±0.26%, 122.9, and 183.5 nm, respectively, with a core-shell structure. The cumulative release rate in vivo of LTG-loaded mixed micelles was 84.21% at 24 hours and showed more sustained release while that of LTG-loaded micelles was 80.61% at 6 hours. The Tmax and area under concentration-time curve from zero to time of last quantifiable concentration of LTG solution, LTG-loaded micelles, and LTG-loaded mixed micelles were 55, 35, and 15 minutes and about 5,384, 16,500, and 25,245 (min⋅µg)/L in the hippocampus, respectively. CONCLUSION: The results revealed that LTG-loaded mPEG-PLA/TPGS mixed micelles enhanced the absorption of LTG at the nasal cavity and reduced the efflux of LTG in the brain, suggesting that the function of TPGS inhibited P-glycoprotein and LTG-loaded mPEG-PLA/TPGS mixed micelles had the potential to overcome refractory epilepsy.

[Relation between drug release and the drug status within curcumin-loaded microsphere].

To study the relation between drug release and the drug status within curcumin-loaded microsphere, SPG (shirasu porous glass) membrane emulsification was used to prepare the curcumin-PLGA (polylactic-co-glycolic acid) microspheres with three levels of drug loading respectively, and the in vitro release was studied with high-performance liquid chromatography (HPLC). The morphology of microspheres was observed with scanning electron microscopy (SEM), and the drug status was studied with X-ray diffraction (XRD), differential scanning calorimetry (DSC) and infrared analysis (IR). The drug loading of microspheres was (5.85 ± 0.21)%, (11.71 ± 0.39)%, (15.41 ± 0.40)%, respectively. No chemical connection was found between curcumin and PLGA. According to the results of XRD, curcumin dispersed in PLGA as amorphous form within the microspheres of the lowest drug loading, while (2.12 ± 0.64)% and (5.66 ± 0.07)% curcumin crystals was detected in the other two kinds of microspheres, respectively, indicating that the drug status was different within three kinds of microspheres. In the data analysis, we found that PLGA had a limited capacity of dissolving curcumin. When the drug loading exceeded the limit, the excess curcumin would exist in the form of crystals in microspheres independently. Meanwhile, this factor contributes to the difference in drug release behavior of the three groups of microspheres.

[Based on in vivo fluorescence imaging technology, to extablish a fluorescence modification method for amphipathic block polymers].

Rhodamine B (Rh B) was used to decorate an amphipathic block polymers (ß-CD-[P(AA- co-MMA)-b-PVP](4)) in this study. First, after activated by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, rhodamine B was marked with hydroxyethyl methacrylate (HEMA) through ester exchange reaction. Second, the labeled amphipathic block polymers (ß-CD-[P(AA-(HEMA-RhB)-MMA)-b-PVP](4)) were synthesized after polymerization reaction of double bones between Rh B-HEMA and other reactants. Finally, the structure of product was measured by FT-IR spectra and fluorospectro photometer (FLUORO). The critical micelle concentration of Rh B-labeled and unlabeled amphipathic block polymers were 4.96×10(-3), 5.09×10(-3)mg·L(-1), respectively, indicating no change of their micellization behavior. In vivo tissue distribution and whole- body fluorescent imaging were studied by vinpocetine (VP)-loaded polymeric micelles which were prepared through a solvent evaporation method. Compared to the result of in vivo tissue distribution and whole-body fluorescence imaging, a similar bio-distribution behavior of VP-loaded polymeric micelles was found. Those proved the successful fluorescence modification with a labeling yield of 4.13%. With in vivo fluorescence imaging technology, we established a fluorescence method for modification of amphipathic block polymers.

The efficacy of nimodipine drug delivery using mPEG-PLA micelles and mPEG-PLA/TPGS mixed micelles.

OBJECTIVE: In order to develop and compare mPEG-PLA micelles and mPEG-PLA/TPGS mixed micelles, with the intention to develop a highly efficient formulation for nimodipine (NIM), NIM-loaded micelles and mixed micelles were made and their pharmacokinetics were studied. METHODS: Single factor experiments and orthogonal experiments were designed to optimize the final preparation process, characterizations and drug release behaviors were studied. Pharmacokinetics of NIM micelles, NIM mixed micelles were researched and were compared to NIM solution. RESULTS: Micelles and mixed micelles were prepared by solvent evaporation method, with relatively high drug loading efficiency and within nano-particle size range. The CMC value of mPEG-PLA was lower than that of mPEG-PLA/TPGS. The results of FTIR and TEM confirmed the spherical core-shell structure of micelles as well as mixed micelles, and the encapsulation of NIM inside the cores. In vitro release showed that micelles and mixed micelles had sustained release effect in the forms of passive diffusion and dissolution process, respectively. Following intraperitoneal administration (5mg/kg), micelles and mixed micelles were absorbed faster than solution, and with larger MRT(0-t), smaller CLz and larger AUC(0-t) as compared to that of solution, which showed micelles and mixed micelles had higher retention, slower elimination and higher bioavailability. This experiment also showed that mixed micelles released NIM more stably than micelles. By evaluate the bioequivalence, NIM micelles and NIM mixed micelles were testified non-bioequivalent to NIM solution. CONCLUSION: Micelles and mixed micelles could sustain the NIM concentrations more efficiently in plasma as compared to solution. Mixed micelles were the best ones since they had high loading content and released more stably. Thus, apprehending micelles and mixed micelles were suited as poor aqueous solubility drug carriers, and mixed micelles were better due to their high loading content and more stable release.

Key interactions for clathrin coat stability.

Clathrin-coated vesicles are major carriers of vesicular traffic in eukaryotic cells. This endocytic pathway relies on cycles of clathrin coat assembly and Hsc70-mediated disassembly. Here we identify histidine residues as major determinants of lattice assembly and stability. They are located at the invariant interface between the proximal and distal segments of clathrin heavy chains, in triskelions centered on two adjacent vertices of the coated-vesicle lattice. Mutation of these histidine residues to glutamine alters the pH dependence of coat stability. We then describe single-particle fluorescence imaging experiments in which we follow the effect of these histidine mutations on susceptibility to Hsc70-dependent uncoating. Coats destabilized by these mutations require fewer Hsc70 molecules to initiate disassembly, as predicted by a model in which Hsc70 traps conformational distortions during the auxilin- and Hsc70:ATP-mediated uncoating reaction.

Protein aggregation can inhibit clathrin-mediated endocytosis by chaperone competition.

Protein conformational diseases exhibit complex pathologies linked to numerous molecular defects. Aggregation of a disease-associated protein causes the misfolding and aggregation of other proteins, but how this interferes with diverse cellular pathways is unclear. Here, we show that aggregation of neurodegenerative disease-related proteins (polyglutamine, huntingtin, ataxin-1, and superoxide dismutase-1) inhibits clathrin-mediated endocytosis (CME) in mammalian cells by aggregate-driven sequestration of the major molecular chaperone heat shock cognate protein 70 (HSC70), which is required to drive multiple steps of CME. CME suppression was also phenocopied by HSC70 RNAi depletion and could be restored by conditionally increasing HSC70 abundance. Aggregation caused dysregulated AMPA receptor internalization and also inhibited CME in primary neurons expressing mutant huntingtin, showing direct relevance of our findings to the pathology in neurodegenerative diseases. We propose that aggregate-associated chaperone competition leads to both gain-of-function and loss-of-function phenotypes as chaperones become functionally depleted from multiple clients, leading to the decline of multiple cellular processes. The inherent properties of chaperones place them at risk, contributing to the complex pathologies of protein conformational diseases.

Structural analysis of the interaction between Dishevelled2 and clathrin AP-2 adaptor, a critical step in noncanonical Wnt signaling.

Wnt association with its receptor, Frizzled (Fz), and recruitment by the latter of an adaptor, Dishevelled (Dvl), initiates signaling through at least two distinct pathways ("canonical" and "noncanonical"). Endocytosis and compartmentalization help determine the signaling outcome. Our previous work has shown that Dvl2 links at least one Frizzled family member (Fz4) to clathrin-mediated endocytosis by interacting with the µ2 subunit of the AP-2 clathrin adaptor, through both a classical endocytic tyrosine motif and a so-called "DEP domain." We report here the crystal structure of a chimeric protein that mimics the Dvl2-µ2 complex. The DEP domain binds at one end of the elongated, C-terminal domain of µ2. This domain:domain interface shows that parts of the µ2 surface distinct from the tyrosine-motif site can help recruit specific receptors or adaptors into a clathrin coated pit. Mutation of residues at the DEP-µ2 contact or in the tyrosine motif reduce affinity of Dvl2 for µ2 and block efficient internalization of Fz4 in response to ligation by Wnt5a. The crystal structure has thus allowed us to identify the specific interaction that leads to Frizzled uptake and to downstream, noncanonical signaling events.

A motif in the clathrin heavy chain required for the Hsc70/auxilin uncoating reaction.

The 70-kDa heat-shock cognate protein (Hsc70) chaperone is an ATP-dependent "disassembly enzyme" for many subcellular structures, including clathrin-coated vesicles where it functions as an uncoating ATPase. Hsc70, and its cochaperone auxilin together catalyze coat disassembly. Like other members of the Hsp70 chaperone family, it is thought that ATP-bound Hsc70 recognizes the clathrin triskelion through an unfolded exposed hydrophobic segment. The best candidate is the unstructured C terminus (residues 1631-1675) of the heavy chain at the foot of the tripod below the hub, containing the sequence motif QLMLT, closely related to the sequence bound preferentially by the substrate groove of Hsc70 (Fotin et al., 2004b). To test this hypothesis, we generated in insect cells recombinant mammalian triskelions that in vitro form clathrin cages and clathrin/AP-2 coats exactly like those assembled from native clathrin. We show that coats assembled from recombinant clathrin are good substrates for ATP- and auxilin-dependent, Hsc70-catalyzed uncoating. Finally, we show that this uncoating reaction proceeds normally when the coats contain recombinant heavy chains truncated C-terminal to the QLMLT motif, but very inefficiently when the motif is absent. Thus, the QLMLT motif is required for Hsc-70-facilitated uncoating, consistent with the proposal that this sequence is a specific target of the chaperone.

Association of Dishevelled with the clathrin AP-2 adaptor is required for Frizzled endocytosis and planar cell polarity signaling.

Upon activation by Wnt, the Frizzled receptor is internalized in a process that requires the recruitment of Dishevelled. We describe a novel interaction between Dishevelled2 (Dvl2) and micro2-adaptin, a subunit of the clathrin adaptor AP-2; this interaction is required to engage activated Frizzled4 with the endocytic machinery and for its internalization. The interaction of Dvl2 with AP-2 requires simultaneous association of the DEP domain and a peptide YHEL motif within Dvl2 with the C terminus of micro2. Dvl2 mutants in the YHEL motif fail to associate with micro2 and AP-2, and prevent Frizzled4 internalization. Corresponding Xenopus Dishevelled mutants show compromised ability to interfere with gastrulation mediated by the planar cell polarity (PCP) pathway. Conversely, a Dvl2 mutant in its DEP domain impaired in PCP signaling exhibits defective AP-2 interaction and prevents the internalization of Frizzled4. We suggest that the direct interaction of Dvl2 with AP-2 is important for Frizzled internalization and Frizzled/PCP signaling.

The small chemical vacuolin-1 inhibits Ca(2+)-dependent lysosomal exocytosis but not cell resealing.

Resealing after wounding, the process of repair following plasma membrane damage, requires exocytosis. Vacuolins are molecules that induce rapid formation of large, swollen structures derived from endosomes and lysosomes by homotypic fusion combined with uncontrolled fusion of the inner and limiting membranes of these organelles. Vacuolin-1, the most potent compound, blocks the Ca(2+)-dependent exocytosis of lysosomes induced by ionomycin or plasma membrane wounding, without affecting the process of resealing. In contrast, other cell structures and membrane trafficking functions including exocytosis of enlargeosomes are unaffected. Because cells heal normally in the presence of vacuolin-1, we suggest that lysosomes are dispensable for resealing.

Resistance to UV-induced apoptosis in Chinese-hamster ovary cells overexpressing phosphatidylserine synthases.

Externalization of PtdSer (phosphatidylserine) is an important event in signalling removal of apoptotic cells. In contrast with previous work [Yu, Byers, Ridgway, McMaster and Cook (2000) Biochim. Biophys. Acta 1487, 296-308] with U937 cells showing that specific stimulation of PtdSer biosynthesis during apoptosis was caspase dependent, PtdSer biosynthesis in CHO (Chinese-hamster ovary)-K1 increased 2.5-fold during UV-induced apoptosis but was not reversed by a caspase inhibitor, Z-VAD-FMK (benzyloxycarbonyl-Val-Ala-DL-Asp-fluoromethylketone). Also, in CHO-K1 cells, stimulation of synthesis was less specific for PtdSer as similar levels of stimulation were observed for sphingomyelin biosynthesis. Involvement of PtdSer synthase isoforms was tested in CHO-K1 cells overexpressing PSS I (PtdSer synthase I) and PSS II. Both types of transformed cells showed resistance to UV-induced apoptosis based on the decreased levels of caspase 3 activation and morphology changes; externalization of PtdSer was reduced with UV treatment even though expression of endogenous scramblase increased slightly. Serine-labelling experiments showed that PSS I- or PSS II-expressing cells had higher basal levels of PtdSer biosynthesis compared with vector control cells. When cells were exposed to UV light to induce apoptosis, PtdSer biosynthesis was further stimulated 1.5- and 2-fold in PSS I- and PSS II-expressing cells respectively compared with UV-treated vector cells. Caspase activation was not required, as Z-VAD-FMK did not change PtdSer synthesis. Although enhanced PtdSer synthesis was supposed to facilitate apoptosis, cells overexpressing PSS I and II were actually resistant to UV-induced apoptosis. Whereas enhanced PtdSer synthesis was associated with apoptosis, potential anti-apoptotic effects were observed when excess activity of these synthetic enzymes was present. This suggests a tightly regulated role for PtdSer synthesis and/or an important dependence on compartmentation of PSS enzymes in association with scramblase facilitated enrichment of this phospholipid at the cell surface.

Stimulation of phosphatidylserine biosynthesis and facilitation of UV-induced apoptosis in Chinese hamster ovary cells overexpressing phospholipid scramblase 1.

Members of the phospholipid scramblase (PLSCR) family play active roles in altering lipid asymmetry at the plasma membrane including phosphatidylserine (PtdSer) exposure on the cell surface. To determine whether PtdSer biosynthesis and externalization are altered by PLSCR activities during apoptosis, Chinese hamster ovary K1 cell lines stably overexpressing PLSCR1 and PLSCR2 were established. PLSCR1 was localized on the plasma membrane, whereas PLSCR2 was predominantly in the nucleus. Cells overexpressing PLSCR1 showed suppressed growth, altered cell morphology, and higher basal levels of cell death. Following UV irradiation, these cells showed earlier and enhanced PtdSer exposure, increased caspase-3 activation, apoptotic nuclear changes, and PARP cleavage indicative of apoptosis. UV irradiation in cells overexpressing PLSCR1 led to a 4-fold stimulation of PtdSer synthesis (accompanied by increased movement of newly made PtdSer into microvesicles) relative to untreated PLSCR1 cells, whereas PtdSer formation in UV-irradiated vector control cells increased only by 2-fold. No differences in these responses were observed between PLSCR2-expressing cells and vector controls. PtdSer synthesis and its transbilayer movement stimulated by PLSCR1 overexpression were blocked by a caspase inhibitor along with progression of apoptosis. Thus, our studies showed that overexpression of PLSCR1 in Chinese hamster ovary K1 cells stimulated caspase-dependent PtdSer externalization and synthesis, implying an up-regulation of PtdSer formation in response to enhanced outward movement of this phospholipid to the cell surface during apoptosis. PLSCR1 also appears to influence progression of UV-induced apoptosis and could be a point of regulation or intervention during programmed cell death.