Insulin and leptin excite anorexigenic pro-opiomelanocortin neurones via activation of TRPC5 channels

Pro-opiomelanocortin (POMC) neurones within the hypothalamic arcuate nucleus are vital anorexigenic neurones. Both the insulin receptor and leptin receptor are coupled to activation of phosphatidylinositide-3 kinase (PI3K) to regulate multiple functions that increase POMC neuronal excitability. Using whole-cell recording in several mammalian species, we have found that both insulin and leptin depolarised POMC neurones via activation of transient receptor potential (TRPC)5 channels. TRPC5 channels have been rigorously characterised as the downstream effector based on their biophysical properties, pharmacological profile, and localisation by immunocytochemistry and single-cell reverse transcriptase-polymerase chain reaction. By contrast, insulin and leptin hyperpolarise and inhibit neuropeptide Y/agouti-related peptide neurones via activation of KATP channels. As proof of principle, insulin given i.c.v. robustly inhibits food intake and increases O2 utilisation, CO2 production and metabolic heat production. Therefore, these findings indicate that the depolarisation/excitation of POMC neurones by insulin and leptin is preserved across mammalian species and the activation of TRPC5 channels is likely a major mechanism by which insulin and leptin regulate energy homeostasis in mammals.

Identification and characterization of a new three-component nicotinic acid hydroxylase NahAB1 B2 from Pusillimonas sp. strain T2

Nicotinic acid (NA) is ubiquitous in nature and its microbial degradation mechanisms are diverse. In this study, Pusillimonas sp. strain T2 was found to be capable of utilizing NA as sole carbon and nitrogen sources. This strain could completely degrade 300 mg l^-1 NA within 3·5 h at 30°C and pH 7·0 and one of the degradation intermediate of NA was identified as 6-hydroxynicotinic acid (6HNA). The draft genome sequences of strain T2 were determined to have a total length of 3·3 M bp and 3054 proteins were predicted. The encoding genes of three-component NA hydroxylase (NahAB₁ B₂ ) genes were identified. The nahAB₁ B₂ genes were heterologously expressed in the non-NA-degrading Shinella sp. strain HZN7. The recombinant HZN7-pBBR-nahAB₁ B₂ converted NA into equimolar 6HNA, while the recombinants HZN7-pBBR-nahAB₁ (lacking component B₂ ) and HZN7-pBBR-nahAB₂ (lacking component B₁ ) could not convert NA. Cell-free extracts of HZN7-pBBR-nahAB₁ B₂ exhibited NA hydroxylase activity. After addition of an artificial electron acceptor (such as phenazine methosulphate, PMS), the NA hydroxylase activity was significantly increased. The K_m and V_max values for NA were 65·94 μmol l^-1 and 260·80 ± 5·69 mU mg^-1 , respectively, using PMS as an electron acceptor. This study provides a novel insight into the NA degradation by bacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

Nicotinic acid (NA) serves as a model system for the degradation of N-heterocyclic aromatic compounds and the microbial degradation mechanisms are diverse. This is the first time that a three-component hydroxylase has been identified. This study provides a novel insight into the NA degradation by bacteria.

Solution and gas phase evidence of anion binding through the secondary bonding interactions of a bidentate bis-antimony(iii) anion receptor

Solution and gas phase evidence of halide binding to a bis-antimony(iii) anion receptor is demonstrated through NMR titrations and ESI-MS.

Quantification of classical HLA class I mRNA by allele-specific, real-time polymerase chain reaction for most Han individuals

Recent studies have shown that expression levels of different alleles at the same HLA class I locus can vary dramatically, which might have a broad influence on human disease. However, precise quantification of the relative expression level of each HLA allele is challenging, because distinguishing different alleles on the same locus is difficult. Here, we developed a series of allele-specific, real-time polymerase chain reaction assays for quantifying HLA class I allele mRNA in most Han individuals. The alleles of almost all heterozygous genotypes with a frequency higher than 0.5% in our population (78 alleles on HLA-A locus, 124 alleles on HLA-B locus, and 74 alleles on HLA-C locus) were specifically amplified. The specificity of the amplification was strictly validated by setting the corresponding negative control for each allele of each genotype. The amplification efficiency of each reaction was determined, and the slopes of the reactions were compared. This study provides a tool for detecting the comprehensive expression profile of HLA class I alleles and will be useful not only for the investigation of the molecular mechanism underlying HLA allele expression regulation but also for exploration of immunological mechanisms involving HLA expression in the fields of tumour immune evasion, viral infection, auto-immune disorders, and graft vs host disease after haematopoietic stem cell transplantation.

Safety and Feasibility Study of a Novel Stent-Graft for Thoracic Endovascular Aortic Repair: a Canine Model Experiment

Objective

To evaluate the safety and feasibility of a novel stent-graft for thoracic endovascular aortic repair (TEVAR) in a canine model, 9 adult hybrid dogs were used for the experiment.

Methods

All animals were implanted with a novel thoracic aortic stent-graft via femoral artery. Blood sample was collected at pre-operation and 1, 2, 4, 8 and 12 weeks after implantation for hematological examination. Moreover, tissues from randomly selected 4 dogs were subjected to histopathological analysis with the optical microscope after stent-grafts were implanted for 3, 6, 9, and 12 months respectively. The experimental period lasted for more than 2 years.

Results

A total of 9 stent-grafts were successfully implanted in the canine thoracic aortas and no migration or deformation occurred. Related indicators of blood routine, inflammatory factors, and immunology changes were not significantly (P>0.05), except the white blood cell (WBC) counts in the first week. Moreover, abnormal morphology was not found in all thoracic aortas via histopathological examination. Additionally, all stent-grafts were patent and did not migrate, and there was no thrombus in the lumens of stent-grafts.

Conclusion

The novel thoracic aortic stent-graft made in China was safe and feasible for thoracic endovascular aortic repair in a canine model.

NO Augments Endothelial Reactivity by Reducing Myoendothelial Calcium Signal Spreading: A Novel Role for Cx37 (Connexin 37) and the Protein Tyrosine Phosphatase SHP-2

OBJECTIVE

Because of its strategic position between endothelial and smooth muscle cells in microvessels, Cx37 (Connexin 37) plays an important role in myoendothelial gap junctional intercellular communication. We have shown before that NO inhibits gap junctional intercellular communication through gap junctions containing Cx37. However, the underlying mechanism is not yet identified.

APPROACH AND RESULTS

Using channel-forming Cx37 mutants exhibiting partial deletions or amino acid exchanges in their C-terminal loops, we now show that the phosphorylation state of a tyrosine residue at position 332 (Y332) in the C-terminus of Cx37 controls the gap junction-dependent spread of calcium signals. Mass spectra revealed that NO protects Cx37 from dephosphorylation at Y332 by inhibition of the protein tyrosine phosphatase SHP-2. Functionally, the inhibition of gap junctional intercellular communication by NO decreased the spread of the calcium signal (induced by mechanical stimulation of individual endothelial cells) from endothelial to smooth muscle cells in intact vessels, while, at the same time, augmenting the calcium signal spreading within the endothelium. Consequently, preincubation of small resistance arteries with exogenous NO enhanced the endothelium-dependent dilator response to acetylcholine in spite of a pharmacological blockade of NO-dependent cGMP formation by the soluable guanylyl cyclase inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one).

CONCLUSIONS

Our results identify a novel mechanism by which NO can increase the efficacy of calcium, rising vasoactive agonists in the microvascular endothelium.

White Leaf and Panicle 2, encoding a PEP-associated protein, is required for chloroplast biogenesis under heat stress in rice

The plastid-encoded RNA polymerase (PEP) plays an important role in the transcription machinery of mature chloroplasts, yet details of its function remain elusive in rice. Here, we identified a novel PEP-associated protein (PAP), WLP2, based on its two allelic white leaf and panicle mutants, wlp2s and wlp2w. The two mutants were albino lethal at high temperatures and showed decreased chlorophyll accumulation, abnormal chloroplast ultrastructure, and attenuated photosynthetic activity. Map-based cloning suggested that WLP2 encodes a putative pfkB-type carbohydrate kinase family protein, which is homologous to fructokinase-like 1 (AtFLN1) in Arabidopsis. WLP2 is mainly expressed in green tissues and its protein localizes in chloroplasts. Expression levels of PEP-encoded genes, chloroplast development genes and photosynthesis-related genes were compromised in wlp2 mutants, indicating that WLP2 is essential for normal chloroplast biogenesis. Moreover, WLP2 and its paralog OsFLN2 can physically interact with thioredoxin OsTRXz to form a TRX-FLN regulatory module, which not only regulates transcription of the PEP-encoded genes but also maintains the redox balance in chloroplasts under heat stress. Furthermore, the wlp2w mutant gene represents a potential advantage in enhancing seed purity and high-throughput breeding. Our results strongly indicate that WLP2 protects chloroplast development from heat stress via a TRX-FLN regulatory module in rice.

The Phosphoproteomic Response of Rice Seedlings to Cadmium Stress

The environmental damage caused by cadmium (Cd) pollution is of increasing concern in China. While the overall plant response to Cd has been investigated in some depth, the contribution (if any) of protein phosphorylation to the detoxification of Cd and the expression of tolerance is uncertain. Here, the molecular basis of the plant response has been explored in hydroponically raised rice seedlings exposed to 10 μΜ and 100 μΜ Cd²⁺ stress. An analysis of the seedlings’ quantitative phosphoproteome identified 2454 phosphosites, associated with 1244 proteins. A total of 482 of these proteins became differentially phosphorylated as a result of exposure to Cd stress; the number of proteins affected in this way was six times greater in the 100 μΜ Cd²⁺ treatment than in the 10 μΜ treatment. A functional analysis of the differentially phosphorylated proteins implied that a significant number was involved in signaling, in stress tolerance and in the neutralization of reactive oxygen species, while there was also a marked representation of transcription factors.

[Clinical features of traumatic optic neuropathy in 265 cases]

Objective: To analyze the clinical features and the pathogenetic law of traumatic optic neuropathy through epidemiologic study. Methods: 265 cases (275 eyes) with TON treated in Department of Otorhinolaryngology Head and Neck Surgery, the Affiliated Hospital of Qingdao University from April 1999 to August 2015 were retrospectively analyzed. Multiple Logistic regression analyses were used to evaluate potential prognostic factors on visual acuity. Results: TON occured mostly in young (194/265, 73.21%) man (235/265, 88.68%), the majority of patients came from villages and towns (209/265, 78.87%). Traffic accident (197/265, 74.34%) remained the main etiology, with strike (36/265, 13.58%) and fall (17/265, 6.42%) as the common etiology. Most patients had head injuries. The effective rate of vision improvement was 53.45%(147/275). Multiple logistic regression analyses identified that initial visual acuity with light perception or better vision, optic canal fracture and orbital wall fracture were visual acuity key factors of TON (χ(2) value was 24.674, 19.755, 9.175, respectively, all P<0.01), initial visual acuity with light perception or better vision was the protective factor on visual acuity recovery (OR=5.008, P<0.001), the presence of optic canal fracture and orbital wall fracture were the risk factors on visual acuity recovery (OR value was 0.110, 0.329, respectively, all P<0.01). Conclusions: Ton occurs mostly in young man because of traffic accident. Visual impairment of TON is severe. The suitable preventive measures should be carried out according to its epidemiological features.

A phosphoproteomic landscape of rice (Oryza sativa) tissues

Protein phosphorylation is an important posttranslational modification that regulates various plant developmental processes. Here, we report a comprehensive, quantitative phosphoproteomic profile of six rice tissues, including callus, leaf, root, shoot meristem, young panicle and mature panicle from Nipponbare by employing a mass spectrometry (MS)-based, label-free approach. A total of 7171 unique phosphorylation sites in 4792 phosphopeptides from 2657 phosphoproteins were identified, of which 4613 peptides were differentially phosphorylated (DP) among the tissues. Motif-X analysis revealed eight significantly enriched motifs, such as [sP], [Rxxs] and [tP] from the rice phosphosites. Hierarchical clustering analysis divided the DP peptides into 63 subgroups, which showed divergent spatial-phosphorylation patterns among tissues. These clustered proteins are functionally related to nutrition uptake in roots, photosynthesis in leaves and tissue differentiation in panicles. Phosphorylations were specific in the tissues where the target proteins execute their functions, suggesting that phosphorylation might be a key mechanism to regulate the protein activity in different tissues. This study greatly expands the rice phosphoproteomic dataset, and also offers insight into the regulatory roles of phosphorylation in tissue development and functions.

The AMP-Related Kinase (AMPK) Induces Ca 2+ -Independent Dilation of Resistance Arteries by Interfering With Actin Filament Formation

Rationale:

Decreasing Ca 2+ sensitivity of vascular smooth muscle (VSM) allows for vasodilation without lowering of cytosolic Ca 2+ . This may be particularly important in states requiring maintained dilation, such as hypoxia. AMP-related kinase (AMPK) is an important cellular energy sensor in VSM. Regulation of Ca 2+ sensitivity usually is attributed to myosin light chain phosphatase activity, but findings in non-VSM identified changes in the actin cytoskeleton. The potential role of AMPK in this setting is widely unknown.

Objective:

To assess the influence of AMPK on the actin cytoskeleton in VSM of resistance arteries with regard to potential Ca 2+ desensitization of VSM contractile apparatus.

Methods and Results:

AMPK induced a slowly developing dilation at unchanged cytosolic Ca 2+ levels in potassium chloride–constricted intact arteries isolated from mouse mesenteric tissue. This dilation was not associated with changes in phosphorylation of myosin light chain or of myosin light chain phosphatase regulatory subunit. Using ultracentrifugation and confocal microscopy, we found that AMPK induced depolymerization of F-actin (filamentous actin). Imaging of arteries from LifeAct mice showed F-actin rarefaction in the midcellular portion of VSM. Immunoblotting revealed that this was associated with activation of the actin severing factor cofilin. Coimmunoprecipitation experiments indicated that AMPK leads to the liberation of cofilin from 14-3-3 protein.

Conclusions:

AMPK induces actin depolymerization, which reduces vascular tone and the response to vasoconstrictors. Our findings demonstrate a new role of AMPK in the control of actin cytoskeletal dynamics, potentially allowing for long-term dilation of microvessels without substantial changes in cytosolic Ca 2+ .

Polygonum multiflorum Radix extract protects human foreskin melanocytes from oxidative stress in vitro and potentiates hair follicle pigmentation ex vivo

OBJECTIVE

To examine the ability of an extract from traditional Chinese medicine, Polygonum multiflorum Radix, to protect melanocyte viability from oxidative stress, a key mechanism in the initiation and progression of hair greying.

METHODS

To assess the antioxidant capacity of Polygonum multiflorum Radix extract, primary human foreskin melanocytes were treated with a commercially available Polygonum multiflorum Radix extract added to culture medium and exposed to hydrogen peroxide (H₂ O₂ ), using intracellular reactive oxygen species concentrations and glutathione/protein ratios as endpoints. To improve solubility for cosmetic uses, a new Polygonum multiflorum Radix extract was derived. As hair greying is the consequence of melanocyte disappearance in an oxidative stress environment, we checked whether the antioxidant capacity of the new Polygonum multiflorum Radix extract could preserve melanocyte viability in response to H₂ O₂ -induced oxidative stress, and preserve pigmentation within ex vivo human hair follicles.

RESULTS

In vitro treatment of primary human foreskin melanocytes with traditional available Polygonum multiflorum Radix extract resulted in decreased intracellular ROS accumulation in response to H₂ O₂ exposure with a concomitant preservation of glutathione-to-protein ratio, consistent with a protective response against H₂ O₂ exposure and demonstrating the promise of this extract for protecting melanocytes against oxidative stress. Melanocytes treated with the improved Polygonum multiflorum Radix extract exhibited attenuated H₂ O₂ -induced cell death, demonstrating a clear cytoprotective effect. Treatment of ex vivo human hair follicles with the improved Polygonum multiflorum Radix extract resulted in a higher level of melanin compared to vehicle-treated controls, demonstrating an ex vivo protective effect on hair pigmentation.

CONCLUSION

Polygonum multiflorum Radix extract protects in vitro primary human foreskin melanocytes from the deleterious effects of H₂ O₂ exposure and improves pigmentation within ex vivo human hair follicles, demonstrating the utility of Polygonum multiflorum Radix extract as a potential active ingredient for the protection of melanocytes against premature death. This data provides in vitro mechanistic evidence consistent with existing in vivo studies for the use of Polygonum multiflorum Radix extract as a strategy for the prevention of oxidative stress-induced hair greying, in line with traditional Polygonum multiflorum Radix uses.