Heterogeneity of myeloid cells in common cancers: Single cell insights and targeting strategies

Tumor microenvironment (TME), is characterized by a complex and heterogenous composition involving a substantial population of immune cells. Myeloid cells comprising over half of the solid tumor mass, are undoubtedly one of the most prominent cell populations associated with tumors. Studies have unambiguously established that myeloid cells play a key role in tumor development, including immune suppression, pro-inflammation, promote tumor metastasis and angiogenesis, for example, tumor-associated macrophages promote tumor progression in a variety of common tumors, including lung cancer, through direct or indirect interactions with the TME. However, due to previous technological constraints, research on myeloid cells often tended to be conducted as studies with low throughput and limited resolution. For example, the conventional categorization of macrophages into M1-like and M2-like subsets based solely on their anti-tumor and pro-tumor roles has disregarded their continuum of states, resulting in an inadequate analysis of the high heterogeneity characterizing myeloid cells. The widespread adoption of single-cell RNA sequencing (scRNA-seq) in tumor immunology has propelled researchers into a new realm of understanding, leading to the establishment of novel subsets and targets. In this review, the origin of myeloid cells in high-incidence cancers, the functions of myeloid cell subsets examined through traditional and single-cell perspectives, as well as specific targeting strategies, are comprehensively outlined. As a result of this endeavor, we will gain a better understanding of myeloid cell heterogeneity, as well as contribute to the development of new therapeutic approaches.

Delivery of Small-Molecule Drugs and Protein Drugs by Injectable Acid-Responsive Self-Assembled COF Hydrogels for Combinatorial Lung Cancer Treatment

Covalent organic frameworks (COFs) have revealed enormous application prospects for cancer therapeutics recently, but their assembly systems face considerable challenges, such as the codelivery of hydrophobic and hydrophilic protein drugs with different physicochemical properties for in vivo delivery and release, as well as endosomal/lysosomal escape of protein drugs. To address these issues, we leveraged the high specific surface area, lipotropism, and structural tunability of boronate ester-linked COFs (COF-1) for the construction of advanced drug delivery systems. We first encapsulated the small-molecule drug doxorubicin (DOX) into a lipophilic COF (COF-1@DOX) and immobilized the functional protein drug ribonuclease A (RNase A) on the surface of the COF (RNase A-COF-1@DOX). We then created a novel composite delivery system (RNase A-COF-1@DOX gel) by cross-linking an albumin-oxygenated hydrogel (gel) network into the pores of COFs, allowing targeted codelivery of protein and small-molecule drugs in vivo. Using in-living body and multichannel fluorescence imaging, we analyzed the in vivo codelivery of protein and small-molecule drugs in a Lewis lung carcinoma (LLC) model. Finally, we applied the RNase A-COF-1@DOX gel to treat lung cancer in mice. This study paves an avenue for constructing COF-based drug delivery systems for lung cancer treatment and holds the potential to be extended to other types of cancer for more effective and targeted therapeutic treatments.

[A case of poisoning caused by head and face bite of Deinagkistrodon acutus]

Snake bites kill and maim many people every year. Head and face venomous snake bite is rare, easy to misdiagnose and miss diagnosis, and the fatality rate is high. In this paper, 1 case of head and face venomous snake bite poisoning was reported and 10 similar cases were reviewed. The clinical characteristics of head and face venomous snake bite poisoning were summarized to provide guidance for clinical diagnosis and treatment. Head and face venomous snake bites may lead to airway injury, edema, and airway obstruction is the main cause of early death. Timely intubation or tracheotomy to maintain oxygen supply and early use of antivenin can improve prognosis.

[Causal links between long-term exposure to NO2 and the risk of cardiovascular hospitalization]

Objective: To determine the causal association between long-term Nitrogen dioxide (NO₂) exposure and the risk of cardiovascular hospitalization. Methods: Based on a sub-cohort of a community-based prospective cohort study, a total of 36 271 participants were recruited from 35 communities randomly selected in Guangzhou in 2015. The annual average exposure of NO₂, demographic characteristics, lifestyle factors, and information on the causes of hospitalization was collected. We applied marginal structural Cox models to investigate the effect of NO₂ on cardiovascular hospitalization. Demographic and behavioral factors also stratified results. Results: The mean age of participants in the present study was (50.9±17.8) years, and the cardiovascular admission rate was 8.7%, with 203 822 person-years of follow-up. The annual mean NO₂ concentration was 48.7 μg/m³ during 2015-2020. For each 10 μg/m³ increase in NO₂ concentrations, the HRs (95%CIs) of total cardiovascular hospitalization, cardiovascular hospitalization, and cerebrovascular hospitalization were 1.33 (1.16-1.52), 1.36 (1.16-1.60) and 1.25 (1.00-1.55), respectively. Participants who were never married/married, with secondary education, high exercise frequency, or non-smokers/current smokers may be more susceptible than their counterparts. Conclusion: Long-term exposure to NO₂ significantly increased hospitalization risk for cardiovascular disease.

[Karst Hydrogeochemical Characteristics and Controlling Factors of Carlin-type Gold Mining Area Based on Hydrochemistry and Sulfur Isotope]

Mining activities change the groundwater level and flow conditions through pumping and drainage, which enhances the interaction between groundwater and aquifer rocks; mine drainage is discharged into the surface water system, which affects the whole karst water hydrogeochemical process. Based on hydrogeochemistry and the δ³⁴S isotope, the hydrogeochemical processes, characteristics, and main controlling factors for waste water, karst groundwater, and surface water in a typical Carlin gold mining area and its surrounding areas were revealed. The results showed that:chemical compositions of groundwater and surface water unaffected by gold mining activities were mainly controlled by the weathering of limestone and dolomitic limestone; Ca²⁺, Mg²⁺, and HCO₃^- were main ions; and the water chemical types were Ca-HCO₃. The mine wastewater and its downstream receiving water were affected by the dissolution of carbonate and silicate minerals, and cation exchange also played a role; the main ions were Ca²⁺, Mg²⁺, Na⁺, and SO₄^2-, and the hydrochemical type gradually evolved from Ca-HCO₃ to Ca-SO₄. SO₄^2- was the characteristic component in various water bodies affected by mining, and the concentration of SO₄^2- gradually decreased from top to bottom in the well. The values of δ³⁴S for unaffected groundwater and surface water were positive, and SO₄^2- was mainly derived from realgar oxidation. Conversely, mine wastewater and downstream water were negative, SO₄^2- was mainly influenced by the mixing action of realgar oxidation and meteoric precipitation, and pyrite also contributed to a certain extent. At the same time, NO₃^- came from agricultural fertilizer and rural domestic sewage discharge directly. Principal component analysis (PCA) further demonstrated:sulfide mineral oxidation and mining activities were the main controlling factors for the water chemical composition of mine wastewater and downstream water, whereas unaffected groundwater and surface water were mainly influenced by water-rock (carbonate rock) interactions. Agricultural fertilizer and rural sewage discharge also had a certain influence. Therefore, the study area should strengthen the interception of surface water, control-block-management of sulfide oxidation, rural domestic sewage treatment, and agricultural fertilizer.

Targeted pharmacokinetics and bioinformatics screening strategy reveals JAK2 as the main target for Xin-Ji-Er-Kang in treatment of MIR injury

BACKGROUND AND PURPOSE

Xin-Ji-Er-Kang (XJEK) is traditional Chinese formula presented excellent protective effects on several heart diseases, but the potential components and targets are still unclear. The aim of this study is to elucidate the effective components of XJEK and reveal its potential mechanism of cardioprotective effect in myocardial ischemia-reperfusion (MIR) injury.

EXPERIMENTAL APPROACH

Firstly, the key compounds in XJEK, plasma and heart tissue were analyzed by high resolution mass spectrometry. Bioinformatics studies were also involved to disclose the potential targets and the binding sites for the key compounds. Secondly, to study the protective effect of XJEK on MIR injury and related mechanism, mice subjected to MIR surgery and gavage administered with XJEK for 6 weeks. Cardiac function parameters and apoptosis level of cardiac tissue were assessed. The potential mechanism was further verified by knock down of target protein in vitro.

RESULTS

Pharmacokinetics studies showed that Sophora flavescens alkaloids, primarily composed with matrine, are the key component of XJEK. And, through bioinformatic analysis, we speculated JAK2 could be the potential target for XJEK, and could form stable hydrogen bonds with matrine. Administration of XJEK and matrine significantly improved heart function and reduced apoptosis of cardiomyocytes by increasing the phosphorylation of JAK2 and STAT3. The anti-apoptosis effect of XJEK and matrine was also observed on AC16 cells, and could be reversed by co-treatment with JAK2 inhibitor AG490 or knock-down of JAK2.

CONCLUSION

XJEK exerts cardioprotective effect on MIR injury, which may be associated with the activation of JAK2/STAT3 signaling pathway.

[Performance of loop-mediated isothermal amplification (LAMP) assay for detection of Schistosoma japonicum infection in Oncomelania snails in schistosomiasis transmission-interrupted regions]

OBJECTIVE

To compare the effectiveness of loop-mediated isothermal amplification (LAMP) assay and microscopic examinations for detection of Schistosoma japonicum infections in Oncomelania hupensis in transmission-interrupted regions, so as to provide insights into the optimization of snail surveillance tools in these regions.

METHODS

Four hilly schistosomiasis-endemic villages where transmission interruption was achieved were selected in Heqing County of Yunnan Province as the study villages, including Xinzhuang and Gule villages in hilly regions and Lianyi and Yitou villages in dam regions. Snail survey was performed by means of systematic sampling combined with environmental sampling in July 2018. All captured snails were identified for S. japonicum infections using microscopy. In addition, 10 to 20 snails were randomly sampled from each snail habitat following microscopy, numbered according to environments and subjected to LAMP assay. The positive rate of settings with S. japonicum-infected snails was compared among villages.

RESULTS

A total of 7 949 living snails were captured from 83 snail habitats in 4 villages, and no S. japonicum infection was detected in snails. There were 226 mixed samples containing 1 786 snails subjected to LAMP assay, and positive LAMP assay was found in 3 mixed samples from 3 snail habitats in 2 dam villages. The positive rates of settings with S. japonicum-infected snails were comparable between Lianyi Village (one setting) and Yitou Village (2 set tings) (5.89% vs. 14.29%, P = 0.344). However, the overall positive rate of settings with S. japonicum-infected snails was significantly higher in dam villages (9.67%, 3/31) than in hilly villages (0) (P = 0.048).

CONCLUSIONS

LAMP assay is more sensitive to detect S. japonicum infections in O. hupensis than conventional microcopy method, which may serve as a supplementary method for detection of S. japonicum infections in O. hupensis in high-risk snail habitats in hilly transmission-interrupted regions.

Early Postmarket Results with EmboTrap II Stent Retriever for Mechanical Thrombectomy: A Multicenter Experience

BACKGROUND AND PURPOSE

EmboTrap II is a novel stent retriever with a dual-layer design and distal mesh designed for acute ischemic stroke emergent large-vessel occlusions. We present the first postmarket prospective multicenter experience with the EmboTrap II stent retriever.

MATERIALS AND METHODS

A prospective registry of patients treated with EmboTrap II at 7 centers following FDA approval was maintained with baseline patient characteristics, treatment details, and clinical/radiographic follow-up.

RESULTS

Seventy patients were treated with EmboTrap II (mean age, 69.9 years; 48.6% women). Intravenous thrombolysis was given in 34.3%, and emergent large-vessel occlusions were located in the ICA (n = 18), M1 (n = 38), M2 or M3 (n = 13), and basilar artery (n = 1). The 5 × 33 mm device was used in 88% of cases. TICI ≥ 2b recanalization was achieved in 95.7% (82.3% in EmboTrap II-only cases), and first-pass efficacy was achieved in 35.7%. The NIHSS score improved from a preoperative average of 16.3 to 12.1 postprocedure and to 10.5 at discharge. An average of 2.5 [SD, 1.8] passes was recorded per treatment, including non-EmboTrap attempts. Definitive treatment was performed with an alternative device (aspiration or stent retriever) in 9 cases (12.9%). Some hemorrhagic conversion was noted in 22.9% of cases, of which 4.3% were symptomatic. There were no device-related complications.

CONCLUSIONS

Initial postmarket results with the EmboTrap II stent retriever are favorable and comparable with those of other commercially available stent retrievers. Compared with EmboTrap II, the first-generation EmboTrap may have a higher first-pass efficacy; however, data are limited by retrospective case analysis, incomplete clinical follow-up, and small sample size, necessitating future trials.

Applications of a Novel Microangioscope for Neuroendovascular Intervention

BACKGROUND AND PURPOSE

Visualization in neuroendovascular intervention currently relies on biplanar fluoroscopy and contrast administration. With the advent of endoscopy, direct visualization of the intracranial intravascular space has become possible with microangioscopes. We analyzed the efficacy of our novel microangioscope to enable direct observation and inspection of the cerebrovasculature, complementary to a standard fluoroscopic technique.

MATERIALS AND METHODS

Iterations of microangioscopes were systematically evaluated for use in neurodiagnostics and neurointerventions in both live animal and human cadaveric models. Imaging quality, trackability, and navigability were assessed. Diagnostic procedures assessed included clot identification and differentiation, plaque identification, inspection for vessel wall injury, and assessment of stent apposition. Interventions performed included angioscope-assisted stent-retriever thrombectomy, clot aspiration, and coil embolization.

RESULTS

The microangioscope was found helpful in both diagnosis and interventions by independent evaluators. Mean ratings of the imaging quality on a 5-point scale ranged from 3.0 (clot identification) to 4.7 (Pipeline follow-up). Mean ratings for clinical utility ranged from 3.0 (aspiration thrombectomy) to 4.7 (aneurysm treatment by coil embolization and WEB device).

CONCLUSIONS

This fiber optic microangioscope can safely navigate and visualize the intravascular space in human cadaveric and in vivo animal models with satisfactory resolution. It has potential value in diagnostic and neurointerventional applications.

Comparison of carcass and meat quality traits between lean and fat Pekin ducks

OBJECTIVE

According to market demand, meat duck breeding mainly includes 2 breeding directions: lean Pekin duck (LPD) and fat Pekin duck (FPD). The aim of the present study was to compare carcass and meat quality traits between 2 strains, and to provide basic data for guidelines of processing and meat quality improvement.

METHODS

A total of 62 female Pekin ducks (32 LPDs and 30 FPDs) were slaughtered at the age of 42 days. The live body weight and carcass traits were measured and calculated. Physical properties of breast muscle were determined by texture analyzer and muscle fibers were measured by paraffin sections. The content of inosine monophosphate (IMP), intramuscular fat (IMF) and fatty acids composition were measured by high-performance liquid chromatography, Soxhlet extraction method and automated gas chromatography respectively.

RESULTS

The results showed that the bodyweight of LPDs was higher than that of FPDs. FPDs were significantly higher than LPDs in subcutaneous fat thickness, subcutaneous fat weight, subcutaneous fat percentage, abdominal fat percentage and abdominal fat shear force (p<0.01). LPDs were significantly higher than FPDs in breast muscle thickness, breast muscle weight, breast muscle rate and breast muscle shear force (p<0.01). The muscle fiber average area and fiber diameter of LPDs were significantly higher than those of FPDs (p<0.01). The muscle fiber density of LPDs was significantly lower than that of FPDs (p<0.01). The IMF of LPDs in the breast muscle was significantly higher than that in the FPDs (p<0.01). There was no significant difference between the 2 strains in IMP content (p>0.05). The polyunsaturated fatty acid content of LPDs was significantly higher than that of FPDs (p<0.01), and FPDs had higher saturated fatty acid and monounsaturated fatty acid levels (p<0.05).

CONCLUSION

Long-term breeding work resulted in vast differences between the two strains Pekin ducks. This study provides a reference for differences between LPD and FPD that manifest as a result of long-term selection.

Dynamics of transcriptome changes during subcutaneous preadipocyte differentiation in ducks

BACKGROUND

Pekin duck is an important animal model for its ability for fat synthesis and deposition. However, transcriptional dynamic regulation of adipose differentiation driven by complex signal cascades remains largely unexplored in this model. This study aimed to explore adipogenic transcriptional dynamics before (proliferation) and after (differentiation) initial preadipocyte differentiation in ducks.

RESULTS

Exogenous oleic acid alone successfully induced duck subcutaneous preadipocyte differentiation. We explored 36 mRNA-seq libraries in order to study transcriptome dynamics during proliferation and differentiation processes at 6 time points. Using robust statistical analysis, we identified 845, 652, 359, 2401 and 1933 genes differentially expressed between -48 h and 0 h, 0 h and 12 h, 12 h and 24 h, 24 h and 48 h, 48 h and 72 h, respectively (FDR < 0.05, FC > 1.5). At the proliferation stage, proliferation related pathways and basic cellular and metabolic processes were inhibited, while regulatory factors that initiate differentiation enter the ready-to-activate state, which provides a precondition for initiating adipose differentiation. According to weighted gene co-expression network analysis, pathways positively related to adipogenic differentiation are significantly activated at the differentiation stage, while WNT, FOXO and other pathways that inhibit preadipocyte differentiation are negatively regulated. Moreover, we identified and classified more than 100 transcription factors that showed significant changes during differentiation, and found novel transcription factors that were not reported to be related to preadipoctye differentiation. Finally, we manually assembled a proposed regulation network model of subcutaneous preadipocyte differentiation base on the expression data, and suggested that E2F1 may serve as an important link between the processes of duck subcutaneous preadipocyte proliferation and differentiation.

CONCLUSIONS

For the first time we comprehensively analyzed the transcriptome dynamics of duck subcutaneous preadipocyte proliferation and differentiation. The current study provides a solid basis for understanding the synthesis and deposition of subcutaneous fat in ducks. Furthermore, the information generated will allow future investigations of specific genes involved in particular stages of duck adipogenesis.

[Quantitative evaluation of the relationship between femoral trochlear dysplasia and the degeneration of the patellofemoral cartilage by using T2mapping]

Objective: To evaluate the relationship between the femoral trochlear dysplasia(FTD) and the degeneration of the patellofemoral cartilage by using MR T2mapping technique. Methods: Sixty two subjects with FTD(aged 18-45 years) were enrolled in Tianjin First Center Hospital from January 2016 to December 2017,the controls which both age and gender were matched.T2mapping scan were aquired for each subject and control. Compare the differences of the T2mapping values for each area between subjects and controls, and compare Dejour types of femoral trochlear in different age groups, respectively. Results: The T2mapping value of subjects was significant lower than controls: the superficial-femoral-lateral layer (sFL) (P=0.000) and the superficial-patella-lateral layer (sPL) (P=0.009). In the group of age less than 30 years, the T2mapping value of subjects was significant lower than controls:sFL (P=0.001) and sPL (P=0.015). In group of age greater than 30 years, the T2mapping value of subjects was significant lower than controls: sFL (P=0.035). In difference Dejour types of FTD, the T2mapping value of type B-D was lowest in sFL(P=0.014),sPL(P=0.000), the superficial-patella-medial layer (sPM) (P=0.020) and the the T2mapping value of type B-D was highest in the deep-femoral-medial layer (dFM) (P=0.006). The difference was statistically significant, P<0.05. Conclusion: The FTD might cause the early degeneration of patellofemoral cartilage, which significantly appear in the young age; The type B-D of FTD is more likely to cause the wider range of superficial cartilage injure and involved some part of deep layer; the injure shows dehydration change in superficial cartilage and edema in deep layer.

iTRAQ-Based Quantitative Proteomic Analysis of Duck Eggshell During Biomineralization

The avian egg is a valuable model for the calcitic biomineralization process as it is the fastest calcification process occurring in nature and is a clear example of biomineralization. In this study, iTRAQ MS/MS is used to detect and study for the first time: 1) the overall duck eggshell proteome; 2) regional differences in the proteome between the inner and outer portions of the duck eggshell. The new reference protein datasets allow us to identify 179 more eggshell proteins than solely using the current release of Ensembl duck annotations. In total, 484 proteins are identified in the entire duck eggshell proteome. Twenty-eight novel proteins of unknown function that are involved in eggshell formation are also identified. Among the identified eggshell proteins, 54 proteins show differential abundances between the inner, partially mineralized eggshell (obtained 16 h after ovulation) compared to the overall complete eggshell (normally expulsed eggshell). At least 64 of the abundant matrix proteins are common to eggshell of 4 different domesticated bird species (chicken, duck, quail, turkey) and zebra finch. This study provides a new resource for avian eggshell proteomics, and augments the inventory of eggshell matrix proteins that will lead to a deeper understanding of calcitic biomineralization.

Genome-wide association study reveals novel loci associated with body size and carcass yields in Pekin ducks

Background

Pekin duck products have become popular in Asia over recent decades and account for an increasing market share. However, the genetic mechanisms affecting carcass growth in Pekin ducks remain unknown. This study aimed to identify quantitative trait loci affecting body size and carcass yields in Pekin ducks.

Results

We measured 18 carcass traits in 639 Pekin ducks and performed genotyping using genotyping-by-sequencing (GBS). Loci-based association analysis detected 37 significant loci for the 17 traits. Thirty-seven identified candidate genes were involved in many biological processes. One single nucleotide polymorphism (SNP) (Chr1_140105435 A > T) located in the intron of the ATPase phospholipid transporting 11A gene (ATP11A) attained genome-wide significance associated with five weight traits. Eight SNPs were significantly associated with three body size traits, including the candidate gene plexin domain containing 2 (PLXDC2) associated with breast width and tensin 3 (TNS3) associated with fossil bone length. Only two SNPs were significantly associated with foot weight and four SNPs were significantly associated with heart weight. In the gene-based analysis, three genes (LOC101791418, TUBGCP3 (encoding tubulin gamma complex-associated protein 3), and ATP11A) were associated with four traits (42-day body weight, eviscerated weight, half-eviscerated weight, and leg muscle weight percentage). However, no loci were significantly associated with leg muscle weight in this study.

Conclusions

The novel results of this study improve our understanding of the genetic mechanisms regulating body growth in ducks and thus provide a genetic basis for breeding programs aimed at maximizing the economic potential of Pekin ducks.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-5379-1) contains supplementary material, which is available to authorized users.

Effect of Selenium Supplementation on Recurrent Hyperthyroidism Caused by Graves' Disease: A Prospective Pilot Study

The effect of selenium supplementation on recurrent hyperthyroidism caused by Graves' disease is unclear. Our study aimed to assess the efficacy of selenium supplementation therapy on recurrent Graves' disease. Forty-one patients with recurrent Graves' disease were enrolled in this study. All patients received the routine treatment using methimazole (MMI), while patients allocated to the selenium group received additional selenium therapy for 6 months. The influence of selenium supplementation on the concentrations of thyroid stimulating hormone (TSH), anti-TSH-receptor antibodies (TRAb), free thyroxine (FT4), and free triiodothyronine (FT3) were assessed. The remission rate was also compared between 2 groups. There was no obvious difference in the demographic data and the levels of serum FT4, FT3, TSH, and TRAb between the 2 groups at baseline. Both FT4 and FT3 decreased more at 2 months in the selenium group than the controls, while the TSH level increased more in patients receiving selenium supplementation (p<0.05). The TRAb level was significantly lower in patients receiving selenium supplementation (2.4 IU/l vs. 5.6 IU/l, p=0.04). The percentages of patients with normal TRAb level at 6 months was also significantly higher in the selenium group (19.0 vs. 0%, p=0.016). Kaplan-Meier survival curve showed patients receiving selenium supplementation had a significantly higher rate of remission than controls (Log-rank test p=0.008). In conclusion, selenium supplementation can enhance the effect of antithyroid drugs in patients with recurrent Graves' disease. Randomized trials with large number of participants are needed to validate the finding above.

The association between S100A13 and HMGA1 in the modulation of thyroid cancer proliferation and invasion

BACKGROUND

S100A13 and high mobility group A (HMGA1) are known to play essential roles in the carcinogenesis and progression of cancer. However, the correlation between S100A13 and HMGA1 during cancer progression is not yet well understood. In this study, we determined the effects of S100A13 on HMGA1 expression in thyroid cancer cells and examined the role of HMGA1 in thyroid cancer progression.

METHODS

Stable ectopic S100A13 expression TT cellular proliferation was evaluated by nude mice xenografts assays. The effect of lentivirus-mediated S100A13 knockdown on thyroid cancer cellular oncogenic properties were evaluated by MTT, colony formation assays and transwell assays in TPC1 and SW579 cells. The effect of siRNA-mediated HMGA1 knockdown on thyroid cancer cellular proliferation and invasion were evaluated by MTT, colony formation assays and transwell assays. The tissue microarray was performed to investigate the correlation between S100A13 and HMGA1 expression in tumor tissues.

RESULTS

The ectopic expression of S100A13 could increase tumor growth in a TT cell xenograft mouse model. Moreover, lentivirus-mediated S100A13 knockdown led to the inhibition of cellular oncogenic properties in thyroid cancer cells, and HMGA1 was found to be involved in the effect of S100A13 on thyroid cancer growth and invasion. Furthermore, siRNA-mediated HMGA1 knockdown was proved to inhibit the growth of TPC1 cells and invasive abilities of SW579 cells. Clinically, it was revealed that both S100A13 and HMGA1 showed a higher expression levels in thyroid cancer cases compared with those in matched normal thyroid cases (P = 0.007 and P = 0.000); S100A13 and HMGA1 expressions were identified to be positively correlated (P = 0.004, R = 0.316) when analyzed regardless of thyroid cancer types.

CONCLUSIONS

This is the first report for the association between HMGA1 and S100A13 expression in the modulation of thyroid cancer growth and invasion. Those results would provide an essential insight into the effect of S100A13 on carcinogenesis of thyroid tumor, rending S100A13 to be potential biological marker for the diagnosis of thyroid cancer.

Molecular characterization of twenty polymorphic microsatellite markers in the polyploid fruit tree species Syzygium samarangense (Myrtaceae)

Syzygium samarangense (Blume) Merr. & Perry (wax apple) is an important commercial fruit tree in Southeast Asia. Here, microsatellite markers were developed to evaluate genetic diversity and distinguish cultivars in this species. In total, 161 microsatellite loci with sufficient flanking sequences to design primer sets were isolated from wax apple using a magnetic bead-enrichment method. Fifty-eight primer sets were designed based on the flanking sequences of each single sequence repeat (SSR) locus and were tested using 14 wax apple cultivars/lines. Twenty SSR loci were found to be polymorphic and transferable across the 14 wax apple cultivars/lines. The number of alleles and effective number of alleles detected per locus ranged from 4 to 12 and from 1.697 to 9.800, respectively. The expected heterozygosity ranged from 0.150 to 0.595 (mean = 0.414). Polymorphism information content values ranged from 0.502 to 0.866 (mean = 0.763). These new microsatellite loci will be of value for characterization of genetic diversity in wax apples and for the identification of cultivars.

A genome-wide SNP scan reveals two loci associated with the chicken resistance to Marek's disease

Marek's disease (MD) is a neoplastic disease in chickens, caused by the Marek's disease virus (MDV). To investigate host genetic resistance to MD, we conducted a genome-wide association study (GWAS) on 67 MDV-infected chickens based on a case and control design, including 57 susceptible chickens in the case group and 10 resistant chickens as controls. After searching 38 655 valid genomic markers, two SNPs were found to be associated with host resistance to MD. One SNP, rs14527240, reaching chromosome-wide significance level (P < 0.01) was located in the SPARC-related modular calcium-binding 1 (SMOC1) gene on GGA5. The other one, GGaluGA156129, reaching genome-wide significance (P < 0.05), was located in the protein tyrosine phosphatase, non-receptor type 3 (PTPN3) gene on GGA2. In addition, expression patterns of these two genes in spleens were detected by qPCR. The expression of SMOC1 was significantly up-regulated (P < 0.05), whereas the expression of PTNP3 did not show significance when the case group was compared with the control group. Up-regulation of SMOC1 in susceptible spleens suggests its important roles in MD tumorigenesis. This is the first study to investigate MD-resistant loci, and it demonstrates the power of GWASs for mapping genes associated with MD resistance.

[Association of differentially expressed genes in the macrophages of spleen in patients with idiopathic thrombocytopenic purpura by cDNA microarray]

OBJECTIVE

To study the differentially expressed genes of splenic macrophage in patients with immune thrombocytopenic purpura.

METHODS

Macrophages were isolated from the spleen. Total RNA of the macrophages were extracted and reversely transcript into cDNA. cDNAs were labeled with Cy5, then hybridized with cDNA chips containing 30968 genes. The gene chips were scanned and analyzed for the differentially expressed genes.

RESULTS

A total of 1545 differentially expressed genes were identified by cDNA chip. 718 genes were highly expressed and 827 genes were down-regulated. The differently expressed genes include those involved in immunologic response, cell adhesion, cell signal transduction, cytoskeleton, exercise metabolism, apoptosis, enzyme regulator activity and so on. The pathway association analysis were related with Toll-like receptor pathway, Fc gamma mediated phagocytosis, MAPK signaling pathway, endocytosis.

CONCLUSION

cDNA mircroarray is an effective technique in screening for differentially expressed genes of the macrophages in patients with ITP. Further analysis of the obtained genes will help understanding the pathogenesis of ITP, and the therapeutic targets.

Polymorphisms in Wnt signaling pathway genes are significantly associated with chicken carcass traits

The Wnt signaling pathway plays a crucial role during embryogenesis in vertebrates. In this study, 124 SNP in 31 Wnt signaling pathway genes were selected to genotype 764 individuals in an F(2) resource population by reciprocally crossing Silkie fowls and Cornish broilers, and 102 SNP were polymorphic. Pairwise linkage disequilibrium among the SNP within each gene was calculated. Haplotypes were reconstructed from the SNP in strong linkage disequilibrium. The associations of SNP and haplotypes with carcass traits were analyzed respectively, and the SNP contributions to phenotypic variance were estimated. The present study showed that 58 SNP in 24 genes and 8 haplotype blocks within 7 genes were significantly (P < 0.05) associated with at least one carcass trait. Fourteen SNP (among the 58 SNP) explained >2% phenotypic variance, 12 of which had significantly (P < 0.01) additive or dominant effects. Furthermore, both rs15865526 (Wnt9A) and rs14066777 (MAPK9) as well as their corresponding haplotype blocks were significantly associated with shank circumference and wing weight, respectively. In addition, 5 muscle-weight-related SNP explained >7% phenotypic variance, which was much higher than those of others. It was found that the Wnt signaling pathway was strongly associated with chicken carcass traits, and 7 genes were particularly important, namely RHOA and CHP for breast muscle weight, Wnt3A for breast muscle weight percentage over carcass weight, RAC1 for thigh weight percentage and thigh muscle weight percentage over carcass weight, Wnt11 for thigh weight percentage over carcass weight, Wnt9A for shank length, and MAPK9 for shank circumference. It is evident that Wnt signaling plays a major role in regulating carcass characteristics important for production traits in chickens.

Low-density lipoprotein receptor-related protein 2 gene is associated with egg-quality traits in dwarf layers

Some members of the low-density lipoprotein receptor (LDLR) family play important roles in the regulation of lipoprotein metabolism and egg quality traits. Low-density lipoprotein receptor-related protein 2 (LRP2) gene belongs to the LDLR super family, and widely expresses in many tissues. This work identified and genotyped 1 single-nucleotide polymorphism (SNP), T14347C, at 3'-UTR of the LRP2 using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS), and analyzed the effects of the SNP (T14347C) on egg-quality traits in 544 dwarf hens from 44 sire families. Frequencies of this SNP in the studied population did not agree with the Hardy-Weinberg equilibrium (P < 0.0001). Egg weight, albumen weight, albumen height, and albumen ratio of the TT genotype were significantly higher than those of the CC genotype (P < 0.05), whereas eggshell ratio of the TT genotype was significantly lower than that of the CC genotype (P < 0.05). The relative expression level of the LRP2 gene in the magnum was determined by real-time quantitative PCR. The gene expression of genotype CC individuals was significantly higher than that of TT and CT birds (P < 0.05). By combining both genetic effects and expression analyses results, we propose that the LRP2 gene is a good candidate gene, exhibiting a key role in albumen formation processes.

Developmental phenotypic-genotypic associations of tyrosinase and melanocortin 1 receptor genes with changing profiles in chicken plumage pigmentation

The tyrosinase (TYR) and melanocortin 1 receptor (MC1R) genes have been accepted as major genes involved in the plumage pigmentation of chickens. The co-segregation of plumage coloration and sequence polymorphism in TYR and MC1R genes were investigated using an intercross between black and white plumage color types of the Dongxiang blue-shelled chicken. Profiles of plumage color changing and genes expression levels of TYR and MC1R were observed from hatch to 112 d of age using quantitative real-time reverse transcription-PCR. Intercrossed offspring were classified by phenotypes of plumage colors. The phenotypes of black and amber chicks with genotypes of E_C_ exhibited a black feather pattern, whereas white, gray, and buff chicks with genotypes of E_cc and eecc belonged to the white feather pattern. Although TYR in cooperation with MC1R determined the coloration feather patterns, the different phenotypes did not correspond completely with the genotypes. During the period studied, plumage phenotype changed dramatically, and the buff and gray down were gradually replaced by whiteness feathers. Real-time reverse transcription-PCR studies showed that 1) expression levels of TYR declined dramatically with age, and expression at hatch was highest (P<0.01) during the ages studied; 2) expression level of MC1R was higher at 28 d than at younger and older ages; and 3) expression of TYR in chickens carrying E/E and E/e alleles on MC1R loci were higher than those carrying e/e alleles from hatch to 28 d.

Expression and distribution of S-100 protein, CD83 and apoptosis-related proteins (Fas, FasL and Bcl-2) in thyroid tissues of autoimmune thyroid diseases

Previous studies have shown that dendritic cells (DCs) and apoptosis-related proteins play a critical role in the pathogenesis of autoimmune thyroid diseases (ATD). This study was designed to investigate the expression and distribution of S-100 protein, CD83 and apoptosis-related proteins (Fas, FasL and Bcl-2) in the thyroid tissues of ATD and their role in ATD pathogenesis as determined by immunochemical staing techniques and other methods. Pathological tissues of 30 patients with Hashimoto's thyroiditis (HT), 30 patients with Graves' disease (GD) and 30 cases of thyroid follicular adenoma (TFA, as control) were used for this study. A higher expression of S-100 in HT (4.2+/-3.1%) and GD (3.9+/-2.8%) vs TFA (0.95+/-0.64%) (p<0.001). was observed as well as a higher expression of CD83 in HT (22.58+/-13.96% and GD (29.92+/-14.43%) vs TFA (5.19+/-8.08%) (p<0.001). HT thyrocytes adjacent to thyroid infiltrating lymphocytes (TILs) showed greater increases in the levels of Fas and FasL than did the GD thyrocytes while HT TILs exhibited lower expression of Fas and FasL than did the GD TILs. GD thyrocytes expressed increased levels of the antiapoptotic protein Bcl-2 as compared to the low levels detected in HT thyrocytes. An opposite pattern was observed in the TILs in GD (low expression of Bcl-2) and HT (high expression of Bcl-2). The findings suggest that the high expression of DC markers is related to the pathogenesis of HT and GD. Up-regulation of both the number and matured functions of DCs may lead to the presentation of more antigens to lymphocytes which are related to the development of autoimmune thyroid diseases. The regulation of Fas/FasL/Bcl-2 in GD favors apoptosis of infiltrating lymphocytes and thyrocyte survival. The regulation of Fas/FasL/Bcl-2 in HT may promote thyrocyte apoptosis leading to hypothyroidism.

Hypercholesterolemia accelerates vascular calcification induced by excessive vitamin D via oxidative stress

Hypercholesterolemia plays an important role in the initiation and progression of atherosclerosis and has a positive correlation with cardiovascular disease. Calcification is a common feature of atherosclerotic lesions and contributes to cardiovascular dysfunctions. The present study investigated the role of hypercholesterolemia in vascular calcification and its potential mechanism. Models of vascular calcification were established by administering vitamin D2 (VD) to rats alone or combined with a high-cholesterol diet (HCD) and by treating rat aorta smooth muscle cells (RASMCs) with beta-glycerophosphate (GP) alone or combined with oxidized low-density lipoprotein (oxLDL) in vitro. In rats, the combination of VD with HCD significantly enhanced vessel calcium deposition and the activity and mRNA expression of vessel alkaline phosphatase (ALP) compared to treatment with VD alone. This combination also enhanced serum levels of total cholesterol, oxLDL, and malondialdehyde as well as vascular production of superoxide anion, while it reduced the vascular activity of superoxide dismutase. Both simvastatin, a cholesterol-lowering agent, and antioxidant vitamin E antagonized the effects of the above combination. In RASMCs, oxLDL accumulation dependently accelerated calcium deposition in cell layers initiated by GP alone. Also, oxLDL stimulated ALP activity and mRNA expression in RASMCs in a concentration-dependent manner. Taken together, these results suggest that acceleration of vascular calcification by hypercholesterolemia might be attributed to oxidative stress and such calcification may be another target of statin or antioxidant action in antiatherosclerosis.

Type 1 and type 3 ryanodine receptors generate different Ca(2+) release event activity in both intact and permeabilized myotubes

In this investigation we use a "dyspedic" myogenic cell line, which does not express any ryanodine receptor (RyR) isoform, to examine the local Ca(2+) release behavior of RyR3 and RyR1 in a homologous cellular system. Expression of RyR3 restored caffeine-sensitive, global Ca(2+) release and causes the appearance of relatively frequent, spontaneous, spatially localized elevations of [Ca(2+)], as well as occasional spontaneous, propagating Ca(2+) release, in both intact and saponin-permeabilized myotubes. Intact myotubes expressing RyR3 did not, however, respond to K(+) depolarization. Expression of RyR1 restored depolarization-induced global Ca(2+) release in intact myotubes and caffeine-induced global release in both intact and permeabilized myotubes. Both intact and permeabilized RyR1-expressing myotubes exhibited relatively infrequent spontaneous Ca(2+) release events. In intact myotubes, the frequency of occurrence and properties of these RyR1-induced events were not altered by partial K(+) depolarization or by application of nifedipine, suggesting that these RyR1 events are independent of the voltage sensor. The events seen in RyR1-expressing myotubes were spatially more extensive than those seen in RyR3-expressing myotubes; however, when analysis was limited to spatially restricted "Ca(2+) spark"-like events, events in RyR3-expressing myotubes were larger in amplitude and duration compared with those in RyR1. Thus, in this skeletal muscle context, differences exist in the spatiotemporal properties and frequency of occurrence of spontaneous release events generated by RyR1 and RyR3. These differences underscore functional differences between the Ca(2+) release behavior of RyR1 and RyR3 in this homologous expression system.

Stereospecific effect of pregabalin on ectopic afferent discharges and neuropathic pain induced by sciatic nerve ligation in rats

BACKGROUND

The new anticonvulsants, gabapentin and pregabalin, are effective in the treatment of neuropathic pain. The sites and mechanisms of their analgesic action are not fully known. The authors have previously demonstrated that systemic gabapentin suppresses ectopic afferent discharges recorded from injured sciatic nerves in rats. In the current study, they further examined the stereospecific effect of pregabalin on neuropathic pain and afferent ectopic discharges in a rodent model of neuropathic pain.

METHODS

Tactile allodynia and thermal hyperalgesia were induced by partial ligation of the left sciatic nerve in rats. Single-unit activity of afferent ectopic discharges was recorded from the sciatic nerve proximal to the site of ligation.

RESULTS

Intravenous injection of 10-30 mg/kg pregabalin dose-dependently attenuated tactile allodynia (n = 10) and thermal hyperalgesia (n = 8). The stereoisomer of pregabalin, R-3-isobutylgaba, had no analgesic effect in this dose range. Furthermore, intravenous injection of pregabalin, but not R-3-isobutylgaba, significantly inhibited the ectopic discharges from injured afferents in a dose-dependent manner (from 20.8 +/- 2.4 impulses/s during control to 2.3 +/- 0.7 impulses/s after treatment with 30 mg/kg pregabalin, n = 15). Pregabalin did not affect the conduction velocity of afferent fibers and the response of normal afferent nerves to mechanical stimulation.

CONCLUSIONS

These data strongly suggest that the analgesic effect of pregabalin on neuropathic pain is likely mediated, at least in part, by its peripheral inhibitory action on the impulse generation of ectopic discharges caused by nerve injury.

Ryanodine sensitizes the Ca(2+) release channel (ryanodine receptor) to Ca(2+) activation

Ryanodine, a plant alkaloid, is one of the most widely used pharmacological probes for intracellular Ca(2+) signaling in a variety of muscle and non-muscle cells. Upon binding to the Ca(2+) release channel (ryanodine receptor), ryanodine causes two major changes in the channel: a reduction in single-channel conductance and a marked increase in open probability. The molecular mechanisms underlying these alterations are not well understood. In the present study, we investigated the gating behavior and Ca(2+) dependence of the wild type (wt) and a mutant cardiac ryanodine receptor (RyR2) after being modified by ryanodine. Single-channel studies revealed that the ryanodine-modified wt RyR2 channel was sensitive to inhibition by Mg(2+) and to activation by caffeine and ATP. In the presence of Mg(2+), the ryanodine-modified single wt RyR2 channel displayed a sigmoidal Ca(2+) dependence with an EC(50) value of 110 nm, whereas the ryanodine-unmodified single wt channel exhibited an EC(50) of 120 microm for Ca(2+) activation, indicating that ryanodine is able to increase the sensitivity of the wt RyR2 channel to Ca(2+) activation by approximately 1,000-fold. Furthermore, ryanodine is able to restore Ca(2+) activation and ligand response of the E3987A mutant RyR2 channel that has been shown to exhibit approximately 1,000-fold reduction in Ca(2+) sensitivity to activation. The E3987A mutation, however, affects neither [(3)H]ryanodine binding to, nor the stimulatory and inhibitory effects of ryanodine on, the RyR2 channel. These results demonstrate that ryanodine does not "lock" the RyR channel into an open state as generally believed; rather, it sensitizes dramatically the channel to activation by Ca(2+).

Antiallodynic effect of intrathecal neostigmine is mediated by spinal nitric oxide in a rat model of diabetic neuropathic pain

BACKGROUND

Intrathecal administration of acetylcholinesterase inhibitors produces antinociception in both animals and humans, but their effect on diabetic neuropathic pain has not been studied. In the current study, we determined the antiallodynic effect of intrathecal injection of an acetylcholinesterase inhibitor, neostigmine, in a rat model of diabetic neuropathic pain. In addition, since acetylcholine can increase release of nitric oxide in the spinal cord, we studied the role of spinal endogenous nitric oxide in the action of intrathecal neostigmine in diabetic neuropathic pain.

METHODS

Rats were rendered diabetic with an intraperitoneal 50-mg/kg injection of streptozotocin. Intrathecal catheters were inserted, with tips in the lumbar intrathecal space. Mechanical allodynia was determined by application of von Frey filaments to the hind paw. We first determined the dose-dependent effect of intrathecal neostigmine on allodynia. The role of spinal nitric oxide in the action of intrathecal neostigmine was then examined through intrathecal treatments with a neuronal nitric oxide synthase inhibitor (TRIM), a nitric oxide scavenger (PTIO), L-arginine, or D-arginine.

RESULTS

The diabetic rats developed a sustained tactile allodynia within 4 weeks after streptozotocin injection. Intrathecal injection of 0.1-0.5 microg neostigmine dose-dependently increased the withdrawal threshold in response to application of von Frey filaments. Intrathecal pretreatment with 30 microg TRIM or 30 microg PTIO abolished the antiallodynic effect of intrathecal neostigmine. Furthermore, the inhibitory effect of TRIM on the action of intrathecal neostigmine was reversed by intrathecal injection of 100 microg L-arginine but not D-arginine.

CONCLUSIONS

Intrathecal neostigmine produces a profound analgesic effect in a rat model of diabetic neuropathic pain. Spinal endogenous nitric oxide contributes to the analgesic action of intrathecal neostigmine in this rat model of diabetic neuropathic pain.

Clinical validation of the related factors and defining characteristics of impaired swallowing for patients with stroke

This exploratory study was conducted to examine the reliability and validity of related factors and defining characteristics of impaired swallowing for stroke patients. Sample of the study included (1) 12 nursing experts, (2) 52 nurses who work in neurological wards, and (3) 107 stroke patients who were divided into a BDST (Burks Dysphagia Screening Test)-positive group (n = 51) and a BDST-negative group (n = 56). Data were collected and validated based on expert validity, diagnostic content validity (DCV), construct validity, and discriminate validity. Results showed that the DCV scores of 17 related factors and 12 defining characteristics were all greater than 0.5. The internal consistency of the 12 defining characteristics was demonstrated by a Cronbach alpha coefficient of 0.89. Two factors were extracted from the 12 defining characteristics after factor analysis; these were "high risk of aspiration with speech disorder" and "ineffectiveness of swallowing". Five major defining characteristics, i.e. pocketing of food, signs of acute aspiration, burning or tickling at the back of the throat, spitting food or food leaking from the mouth, and weak or hoarse cough, were determined by logistic regression. The findings of this study suggest that the 17 related factors and 12 defining characteristics are reliable and valid in diagnosing the problem of impaired swallowing for stroke patients.

Spinal endogenous acetylcholine contributes to the analgesic effect of systemic morphine in rats

BACKGROUND

Systemic morphine is known to cause increased release of acetyicholine in the spinal cord. Intrathecal injection of the cholinergic receptor agonists or acetyicholinesterase inhibitors produces antinociception in both animals and humans. In the present study, we explored the functional importance of spinal endogenous acetylcholine in the analgesic action produced by intravenous morphine.

METHODS

Rats were implanted with intravenous and intrathecal catheters. The antinociceptive effect of morphine was determined by the paw-withdrawal latency in response to a radiant heat stimulus after intrathecal treatment with atropine (a muscarinic receptor antagonist), mecamylamine (a nicotinic receptor antagonist), or cholinergic neurotoxins (ethylcholine mustard aziridinium ion [AF64A] and hemicholinium-3).

RESULTS

Intravenous injection of 2.5 mg/kg morphine increased significantly the paw-withdrawal latency. Intrathecal pretreatment with 30 microg atropine (n = 7) or 50 microg mecamylamine (n = 6) both attenuated significantly the antinociceptive effect of morphine. The inhibitory effect of atropine on the effect of morphine was greater than that of mecamylanilne. Furthermore, the antinociceptive effect of morphine was significantly reduced in rats pretreated with intrathecal AF64A (n = 7) or hemicholinium-3 (n = 6) to inhibit the high-affinity choline transporter and acetylcholine synthesis. We found that intrathecal AF64A reduced significantly the [3H]hemicholinium-3 binding sites but did not affect its affinity in the dorsal spinal cord.

CONCLUSIONS

The data in the current study indicate that spinal endogenous acetylcholine plays an important role in mediating the analgesic effect of systemic morphine through both muscarinic and nicotinic receptors.

Differential responses of regional sympathetic activity and blood flow to visceral afferent stimulation

The sympathetic nervous system is essential for the cardiovascular responses to stimulation of visceral afferents. It remains unclear how the reflex-evoked sympathetic output is distributed to different vascular beds to initiate the hemodynamic changes. In the present study, we examined changes in regional sympathetic nerve activity and blood flows in anesthetized cats. Cardiovascular reflexes were induced by either electrical stimulation of the right splanchnic nerve or application of 10 μg/ml of bradykinin to the gallbladder. Blood flows were measured using colored microspheres or the Transonic flow meter system. Sympathetic efferent activity was recorded from the left splanchnic, inferior cardiac, and tibial nerves. Stimulation of visceral afferents decreased significantly blood flows in the celiac (from 49 ± 4 to 25 ± 3 ml/min) and superior mesenteric (from 35 ± 4 to 23 ± 2 ml/min) arteries, and the vascular resistance in the splanchnic bed was profoundly increased. Consistently, stimulation of visceral afferents decreased tissue blood flows in the splanchnic organs. By contrast, activation of visceral afferents increased significantly blood flows in the coronary artery and portal vein but did not alter the vascular resistance of the femoral artery. Furthermore, stimulation of visceral afferents increased significantly sympathetic efferent activity in the splanchnic (182 ± 44%) but not in the inferior cardiac and tibial nerves. Therefore, this study provides substantial new evidence that stimulation of abdominal visceral afferents differentially induces sympathetic outflow to the splanchnic vascular bed.

Three-dimensional reconstruction of the recombinant type 3 ryanodine receptor and localization of its amino terminus

Recombinant type 3 ryanodine receptor (RyR3) has been purified in quantities sufficient for structural characterization by cryoelectron microscopy and three-dimensional (3D) reconstruction. Two cDNAs were prepared and expressed in HEK293 cells, one encoding the wild-type RyR3 and the other encoding RyR3 containing glutathione S-transferase (GST) fused to its amino terminus (GST-RyR3). RyR3 was purified from detergent-solubilized transfected cells by affinity chromatography using 12.6-kDa FK506-binding protein in the form of a GST fusion as the affinity ligand. Purification of GST-RyR3 was achieved by affinity chromatography by using glutathione-Sepharose. Purified recombinant RyR3 and GST-RyR3 proteins exhibited high-affinity [(3)H]ryanodine binding that was sensitive to activation by Ca(2+) and caffeine and to inhibition by Mg(2+). 3D reconstructions of both recombinant RyR3 and GST-RyR3 appeared very similar to that of the native RyR3 purified from bovine diaphragm. Comparison of the 3D reconstructions of RyR3 and GST-RyR3 revealed that the GST domains and, hence, the amino termini of the RyR3 subunits are located in the "clamp" structures that form the corners of the square-shaped cytoplasmic region of homotetrameric RyR3. This study describes the 3D reconstruction of a recombinant ryanodine receptor and it demonstrates the potential of this technology for characterizing functional and structural perturbations introduced by site-directed mutagenesis.

Dantrolene inhibition of ryanodine receptor Ca2+ release channels. Molecular mechanism and isoform selectivity

As an inhibitor of Ca(2+) release through ryanodine receptor (RYR) channels, the skeletal muscle relaxant dantrolene has proven to be both a valuable experimental probe of intracellular Ca(2+) signaling and a lifesaving treatment for the pharmacogenetic disorder malignant hyperthermia. However, the molecular basis and specificity of the actions of dantrolene on RYR channels have remained in question. Here we utilize [(3)H]ryanodine binding to further investigate the actions of dantrolene on the three mammalian RYR isoforms. The inhibition of the pig skeletal muscle RYR1 by dantrolene (10 microm) was associated with a 3-fold increase in the K(d) of [(3)H]ryanodine binding to sarcoplasmic reticulum (SR) vesicles such that dantrolene effectively reversed the 3-fold decrease in the K(d) for [(3)H]ryanodine binding resulting from the malignant hyperthermia RYR1 Arg(615) --> Cys mutation. Dantrolene inhibition of the RYR1 was dependent on the presence of the adenine nucleotide and calmodulin and reflected a selective decrease in the apparent affinity of RYR1 activation sites for Ca(2+) relative to Mg(2+). In contrast to the RYR1 isoform, the cardiac RYR2 isoform was unaffected by dantrolene, both in native cardiac SR vesicles and when heterologously expressed in HEK-293 cells. By comparison, the RYR3 isoform expressed in HEK-293 cells was significantly inhibited by dantrolene, and the extent of RYR3 inhibition was similar to that displayed by the RYR1 in native SR vesicles. Our results thus indicate that both the RYR1 and the RYR3, but not the RYR2, may be targets for dantrolene inhibition in vivo.

Intrathecal S-nitroso-N-acetylpenicillamine and L-cysteine attenuate nerve injury-induced allodynia through noradrenergic activation in rats

Spinal norepinephrine release and activation of spinal alpha(2)-adrenergic receptors represent important components of descending control of nociception. Recent studies have shown that nitric oxide is capable of stimulating neuronal norepinephrine release in the presence of thiol-containing compounds such as L-cysteine. In the present study, we tested a hypothesis in a rodent model of neuropathic pain that intrathecal injection of the nitric oxide donor S-nitroso-N-acetylpenicillamine and L-cysteine produces an antiallodynic action mediated by the spinal alpha(2)-adrenergic receptors. Allodynia was induced in rats by ligation of the left lumbar L5/L6 spinal nerves. Mechanical allodynia was quantified by application of von Frey filaments to the left hindpaw. Intrathecal injection of 20-100microg of S-nitroso-N-acetylpenicillamine in the presence of 200microg of L-cysteine, but not D-cysteine, dose-dependently attenuated the allodynia. Intrathecal injection of a combination of 100microg of S-nitroso-N-acetylpenicillamine and 50-200microg of L-cysteine also inhibited the allodynia in a dose-dependent manner. Pretreatment with a nitric oxide scavenger, carboxy-PTIO, or depletion of norepinephrine with a specific neurotoxin, N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine, prevented the antiallodynic action of intrathecal S-nitroso-N-acetylpenicillamine and L-cysteine. Furthermore, the antiallodynic effect produced by intrathecal injection of a combination of S-nitroso-N-acetylpenicillamine and L-cysteine was abolished by pretreatment with intrathecal injection of a non-specific alpha-adrenergic receptor antagonist, phentolamine, or an alpha(2) receptor antagonist, idazoxan. This study provides the first functional evidence that spinal nitric oxide interacts with the thiol-containing compounds to produce an antiallodynic effect in neuropathic pain. We propose that such an action is mediated by endogenous norepinephrine and spinal alpha(2)-adrenergic receptors.

Herniated blastomere following chemically assisted hatching may result in monozygotic twins

OBJECTIVE

To explore a possible mechanism of the increasing incidence of monozygotic twins following assisted hatching of human embryos.

DESIGN

Case report.

SETTING

Clinical research center in a medical school teaching hospital.

PATIENT

A 37-year-old infertile woman with repeated IVF failures.

INTERVENTION(S)

Assisted hatching of the day 3 embryos using acidic Tyrode's solution.

MAIN OUTCOME MEASURE(S)

The morphology of the zona-drilled embryos and the pregnancy outcome.

RESULT(S)

After assisted hatching, a herniated blastomere through an oversized opening in the zona pellucida was found in one embryo. The transfer of two zona-drilled embryos resulted in a triplet pregnancy.

CONCLUSION(S)

Large openings in the zona pellucida following chemically assisted hatching may cause premature hatching of the blastomeres and may be implicated in the occurrence of monozygotic twins.

RYR1 and RYR3 have different roles in the assembly of calcium release units of skeletal muscle

Calcium release units (CRUs) are junctions between the sarcoplasmic reticulum (SR) and exterior membranes that mediates excitation contraction (e-c) coupling in muscle cells. In skeletal muscle CRUs contain two isoforms of the sarcoplasmic reticulum Ca(2+)release channel: ryanodine receptors type 1 and type 3 (RyR1 and RyR3). 1B5s are a mouse skeletal muscle cell line that carries a null mutation for RyR1 and does not express either RyR1 or RyR3. These cells develop dyspedic SR/exterior membrane junctions (i.e., dyspedic calcium release units, dCRUs) that contain dihydropyridine receptors (DHPRs) and triadin, two essential components of CRUs, but no RyRs (or feet). Lack of RyRs in turn affects the disposition of DHPRs, which is normally dictated by a linkage to RyR subunits. In the dCRUs of 1B5 cells, DHPRs are neither grouped into tetrads nor aligned in two orthogonal directions. We have explored the structural role of RyR3 in the assembly of CRUs in 1B5 cells independently expressing either RyR1 or RyR3. Either isoform colocalizes with DHPRs and triadin at the cell periphery. Electron microscopy shows that expression of either isoform results in CRUs containing arrays of feet, indicating the ability of both isoforms to be targeted to dCRUs and to assemble in ordered arrays in the absence of the other. However, a significant difference between RyR1- and RyR3-rescued junctions is revealed by freeze fracture. While cells transfected with RyR1 show restoration of DHPR tetrads and DHPR orthogonal alignment indicative of a link to RyRs, those transfected with RyR3 do not. This indicates that RyR3 fails to link to DHPRs in a specific manner. This morphological evidence supports the hypothesis that activation of RyR3 in skeletal muscle cells must be indirect and provides the basis for failure of e-c coupling in muscle cells containing RyR3 but lacking RyR1 (see the accompanying report, ).

Divergent functional properties of ryanodine receptor types 1 and 3 expressed in a myogenic cell line

Of the three known ryanodine receptor (RyR) isoforms expressed in muscle, RyR1 and RyR2 have well-defined roles in contraction. However, studies on mammalian RyR3 have been difficult because of low expression levels relative to RyR1 or RyR2. Using the herpes simplex virus 1 (HSV-1) helper-free amplicon system, we expressed either RyR1 or RyR3 in 1B5 RyR-deficient myotubes. Western blot analysis revealed that RyR1- or RyR3-transduced cells expressed the appropriate RyR isoform of the correct molecular mass. Although RyR1 channels exhibited the expected unitary conductance for Cs(+) in bilayer lipid membranes, 74 of 88 RyR3 channels exhibited pronounced subconductance behavior. Western blot analysis with an FKBP12/12.6-selective antibody reveals that differences in gating behavior exhibited by RyR1 and RyR3 may be, in part, the result of lower affinity of RyR3 for FKBP12. In calcium imaging studies, RyR1 restored skeletal-type excitation-contraction coupling, whereas RyR3 did not. Although RyR3-expressing myotubes were more sensitive to caffeine than those expressing RyR1, they were much less sensitive to 4-chloro-m-cresol (CMC). In RyR1-expressing cells, regenerative calcium oscillations were observed in response to caffeine and CMC but were never seen in RyR3-expressing 1B5 cells. In [(3)H]ryanodine binding studies, only RyR1 exhibited sensitivity to CMC, but both RyR isoforms responded to caffeine. These functional differences between RyR1 and RyR3 expressed in a mammalian muscle context may reflect differences in association with accessory proteins, especially FKBP12, as well as structural differences in modulator binding sites.

Spinal cyclooxygenase-2 is involved in development of allodynia after nerve injury in rats

Increased spinal cyclooxygenase activity is associated with nociception induced by tissue inflammation. In the present study, we examined the changes of cyclooxygenase-1 and cyclooxygenase-2 protein expression in several regions of the CNS associated with pain perception, and the role of spinal cyclooxygenase activity in the development of allodynia following nerve injury. Allodynia was induced by ligation of the left L5 and L6 spinal nerves in rats. Using western blot analysis, we found that the cyclooxygenase-2 protein levels in the dorsal spinal cord and thalamus (but not in the ventral spinal cord, cingulate cortex and locus coeruleus) increased significantly one day after nerve ligation, compared with those in the sham animals. The cyclooxygenase-2 protein levels in the above tissues were similar in nerve-injured and sham animals three and 14 days after surgery. In contrast, cyclooxygenase-1 protein was not detectable in any of the neural tissues examined one, three, and 14 days after nerve injury. In the behavioral experiments, we observed that intrathecal injection of 100microg of indomethacin immediately or one day after nerve ligation attenuated the development of tactile allodynia. However, intrathecal injection of indomethacin had no effect on established allodynia two weeks after nerve injury.Collectively, our results suggest that cyclooxygenase-2 is preferentially up-regulated in the dorsal spinal cord and thalamus in response to nerve injury in rats. Spinal cyclooxygenase-2 probably plays an important role in the early development, but not in the maintenance, of tactile allodynia caused by the nerve injury in this rat model of neuropathic pain.

Cardiac interstitial bradykinin release during ischemia is enhanced by ischemic preconditioning

Ischemic preconditioning is known to protect the myocardium from ischemia-reperfusion injury. We examined the transmural release of bradykinin during myocardial ischemia and the influence of ischemic preconditioning on bradykinin release during subsequent myocardial ischemia. Myocardial ischemia was induced by occlusion of the left anterior descending coronary artery in anesthetized cats. Cardiac microdialysis was performed by implantation and perfusion of dialysis probes in the epicardium and endocardium. In eight animals, bradykinin release was greater in the endocardium than in the epicardium (14.4 +/- 2.8 vs. 7.3 +/- 1.7 ng/ml, P < 0.05) during 30 min of ischemia. In seven animals subjected to preconditioning, myocardial bradykinin release was potentiated significantly from 2.4 +/- 0.6 ng/ml during the control period to 23.1 +/- 2.5 ng/ml during 30 min of myocardial ischemia compared with the non-preconditioning group (from 2.7 +/- 0.6 to 13.4 +/- 1.9 ng/ml, P < 0.05, n = 6). Thus this study provides further evidence that transmural gradients of bradykinin are produced during ischemia. The results also suggest that ischemic preconditioning enhances bradykinin release in the myocardial interstitial fluid during subsequent ischemia, which is likely one of the mechanisms of cardioprotection of ischemic preconditioning.

Expression of ryanodine receptor RyR3 produces Ca2+ sparks in dyspedic myotubes

Discrete, localized elevations of myoplasmic [Ca2+], Ca2+ 'sparks', were readily detected using the fluorescent Ca2+ indicator fluo-3 and laser scanning confocal microscopy in 'dyspedic' 1B5 myotubes, i.e. myotubes which do not express ryanodine receptors (RyRs), transduced with virions containing cDNA for RyR type 3 that were saponin permeabilized to allow dye entry. Ca2+ sparks were never observed in non-transduced RyR null myotubes. The spatial locations of sparks observed in permeabilized myotubes roughly corresponded to regions of RyR protein expression in the same myotube as detected after subsequent fixation and antibody staining. Permeabilized RyR3-transduced myotubes exhibited similar punctate peripheral RyR3 protein immunohistochemical patterns as myotubes fixed before permeabilization indicating that permeabilization did not affect the structural organization of the triad. Ca2+ sparks, recorded in line scan mode, in permeabilized myotubes expressing RyR3 exhibited mean amplitudes (change in fluorescence/mean fluorescence, DeltaF/F: 1.20 +/- 0.04) and temporal rise times (10-90%; 6.31 +/- 0.12 ms) similar to those of sparks recorded in permeabilized frog skeletal muscle fibres (0.98 +/- 0.01; 6.11 +/- 0.07, respectively) using the same confocal system. Spatial extent and temporal duration of the Ca2+ sparks were approximately 40% larger in the RyR3-expressing myotube cultures than in frog fibres. Ca2+ sparks recorded in line scan mode often occurred repetitively at the same spatial location in RyR3-expressing myotubes. Such repetitive events were highly reproducible in amplitude and spatio-temporal properties, as previously observed for repetitive mode sparks in frog skeletal muscle. Ca2+ sparks recorded in xy mode were frequently compressed in the y (slower scan) direction compared to the x direction. This asymmetry was reproduced assuming spatially symmetric events having the time course of Ca2+ sparks recorded in line scan (xt) mode. These expression studies demonstrate that the presence of RyR3 is sufficient for the production of Ca2+ sparks in a skeletal muscle system lacking the expression of any other RyR isoform.

Role of spinal muscarinic and nicotinic receptors in clonidine-induced nitric oxide release in a rat model of neuropathic pain

Intrathecal administration of alpha(2) adrenergic agonists, such as clonidine, is capable of alleviating neuropathic pain. Recent studies suggest that spinal nitric oxide (NO) mediates the analgesic effect of intrathecal clonidine. Furthermore, compared to nicotinic receptors, spinal muscarinic receptors play a greater role in the analgesic effect of intrathecal clonidine. In the present study, we tested a hypothesis that clonidine-evoked NO release is dependent primarily on muscarinic receptors in the spinal cord after nerve injury. A rat model of neuropathic pain was induced by ligation of the left L(5)/L(6) spinal nerves. Using an in vitro spinal cord perfusion preparation, the effect of muscarinic and nicotinic receptor antagonists on clonidine-evoked nitrite (a stable product of NO) release was determined. Both muscarinic and nicotinic antagonists dose-dependently attenuated clonidine-elicited nitrite release. In spinal cords from the neuropathic rats, the inhibitory effect of muscarinic receptor antagonists (atropine and scopolamine) on clonidine-elicited nitrite release was more potent than that of nicotinic receptor antagonists (mecamylamine and hexamethonium). However, in spinal cords obtained from sham animals, the inhibitory effect of muscarinic and nicotinic antagonists did not differ significantly. These results indicate that muscarinic, as well as nicotinic, receptors mediate clonidine-induced NO release in the spinal cord. These data also suggest that after nerve injury, the cascade of activation of alpha(2) adrenergic receptors-muscarinic receptors-NO in the spinal cord likely plays a predominant role in the analgesic effect of intrathecal clonidine on neuropathic pain.

Synergistic effect between intrathecal non-NMDA antagonist and gabapentin on allodynia induced by spinal nerve ligation in rats

BACKGROUND

Glutamate and non-N-methyl-D-aspartate (NMDA) receptors have been implicated in the development of neuroplasticity in the spinal cord in neuropathic pain. The spinal cord has been identified as one of the sites of the analgesic action of gabapentin. In the current study, the authors determined the antiallodynic effect of intrathecal 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) in a rat model of neuropathic pain. Also tested was a hypothesis that intrathecal injection of CNQX and gabapentin produces a synergistic effect on allodynia in neuropathic rats.

METHODS

Allodynia was produced in rats by ligation of the left L5 and L6 spinal nerves. Allodynia was determined by application of von Frey filaments to the left hind paw. Through an implanted intrathecal catheter, 10-100 microg gabapentin or 0.5-8 microg CNQX disodium (a water-soluble formulation of CNQX) was injected in conscious rats. Isobolographic analysis was performed comparing the interaction of intrathecal gabapentin and CNQX using the ED50 dose ratio of 15:1.

RESULTS

Intrathecal treatment with gabapentin or CNQX produced a dose-dependent increase in the withdrawal threshold to mechanical stimulation. The ED50 for gabapentin and CNQX was 45.9+/-4.65 and 3.4+/-0.22 microg, respectively. Intrathecal injection of a combination of CNQX and gabapentin produced a strong synergistic antiallodynic effect in neuropathic rats.

CONCLUSIONS

This study shows that intrathecal administration of CNQX exhibits an antiallodynic effect in this rat model of neuropathic pain. Furthermore, CNQX and gabapentin, when combined intrathecally, produce a potent synergistic antiallodynic effect on neuropathic pain in spinal nerve-ligated rats.

The RCAF complex mediates chromatin assembly during DNA replication and repair

Chromatin assembly is a fundamental biological process that is essential for the replication and maintenance of the eukaryotic genome. In dividing cells, newly synthesized DNA is rapidly assembled into chromatin by the deposition of a tetramer of the histone proteins H3 and H4, followed by the deposition of two dimers of histones H2A and H2B to complete the nucleosome-the fundamental repeating unit of chromatin. Here we describe the identification, purification, cloning, and characterization of replication-coupling assembly factor (RCAF), a novel protein complex that facilitates the assembly of nucleosomes onto newly replicated DNA in vitro. RCAF comprises the Drosophila homologue of anti-silencing function 1 protein ASF1 and histones H3 and H4. The specific acetylation pattern of H3 and H4 in RCAF is identical to that of newly synthesized histones. Genetic analyses in Saccharomyces cerevisiae demonstrate that ASF1 is essential for normal cell cycle progression, and suggest that RCAF mediates chromatin assembly after DNA replication and the repair of double-strand DNA damage in vivo.

HEK-293 cells possess a carbachol- and thapsigargin-sensitive intracellular Ca2+ store that is responsive to stop-flow medium changes and insensitive to caffeine and ryanodine

Because HEK-293 cells are widely used for the functional expression of channels, exchangers and transporters involved in Ca(2+) homoeostasis, the properties of intracellular Ca(2+) stores and the methods used for measuring intracellular Ca(2+) release in HEK-293 cells were evaluated. Ca(2+) imaging was used to show caffeine-, carbachol- and thapsigargin-induced Ca(2+) release in HEK-293 cells transfected with ryanodine receptor (RyR) cDNA, but only carbachol- and thapsigargin-induced Ca(2+) release in untransfected HEK-293 cells. Intracellular Ca(2+) release in untransfected HEK-293 cells was also observed if medium changes were performed by aspirating and replacing fresh medium (stop-flow), but not if medium changes were performed by a continuous over-flow procedure. Stop-flow medium-change-induced Ca(2+) release in HEK-293 cells was independent of caffeine and ryanodine, demonstrating that it did not occur through RyR channels. Consistent with these observations was the observation that the level of expression of endogenous RyR proteins was below the limits of detection by Western blotting or [(3)H]ryanodine binding. Thus the level of endogenous expression of RyR is so low in HEK-293 cells as to provide a negligible background in relation to functional analysis of recombinant RyR molecules. These results are inconsistent with those of Querfurth et al. [Querfurth, Haughey, Greenway, Yacono, Golan and Geiger (1998) Biochem. J. 334, 79-86], who reported higher levels of endogenous RyR expression in untransfected HEK-293 cells.

Molecular identification of the ryanodine receptor pore-forming segment

A sequence motif, GXRXGGGXGD, located in the putative channel-forming domain, is conserved in all known ryanodine receptors and inositol 1,4,5-trisphosphate receptors. The functional significance of this conserved region was investigated by using site-directed mutagenesis together with functional assays consisting of Ca(2+) release measurements, [(3)H]ryanodine binding, and single channel recordings in planar lipid bilayers. We report here that single point mutations introduced into this region of the mouse cardiac ryanodine receptor reduce or abolish high affinity [(3)H]ryanodine binding. Single channel analysis revealed that a single substitution of alanine for glycine 4824 within this region reduced the single channel conductance by 97%, from 798 picosiemens (pS) for the wild type channel to 22 pS. The G4824A mutant channel was modulated by Ca(2+), Mg(2+), ATP, caffeine, ruthenium red, and ryanodine. Co-expression of the wild type and G4824A mutant proteins produced single channels that have intermediate unitary conductances of 516, 256, 176, and 60 pS. These data suggest that this conserved region constitutes an essential part of the ryanodine binding site and the channel conduction pathway of the ryanodine receptor.