Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 34
Filter
Add more filters










Publication year range
1.
Article in English | MEDLINE | ID: mdl-38415447

ABSTRACT

BACKGROUND: A high-salt diet is a leading dietary risk factor for elevated blood pressure and cardiovascular disease. Quercetin reportedly exhibits cardioprotective and antihypertensive therapeutic effects. OBJECTIVES: The objective of this study is to examine the effect of quercetin on high-salt dietinduced elevated blood pressure in Dahl salt-sensitive (SS) rats and determine the underlying molecular mechanism. MATERIALS AND METHODS: Rats of the Dahl SS and control SS-13 BN strains were separated into five groups, SS-13 BN rats fed a low-salt diet (BL group), SS-13 BN rats fed a high-salt diet (BH group), Dahl SS rats fed a low-salt diet (SL group), Dahl SS rats fed a high-salt diet (SH group), and SH rats treated with quercetin (SHQ group). Blood pressure was checked three weeks into the course of treatment, and biochemical markers in the urine and serum were examined. Additionally, western blot was done to evaluate the sirtuin 1 (SIRT1) and endothelial nitric oxide synthase (eNOS) expression levels. Immunohistochemical analysis was performed to verify SIRT1 levels. RESULTS: We demonstrated that a high-salt diet elevated blood pressure in both SS-13 BN and Dahl SS rats, and quercetin supplementation alleviated the altered blood pressure. Compared with the SH group, quercetin significantly elevated the protein expression of SIRT1 and eNOS. Immunohistochemistry results further confirmed that quercetin could improve the protein expression of SIRT1. CONCLUSION: Quercetin reduced blood pressure by enhancing the expression of SIRT1 and eNOS in Dahl SS rats fed a high-salt diet.

2.
Discov Med ; 34(171): 25-32, 2022.
Article in English | MEDLINE | ID: mdl-36320089

ABSTRACT

Human beings develop a highly coordinated and flexible system of social behavior and threat evaluation. In this review we focus on the unique role of early life adversity (ELA) in programming deficits in social behavior and threat processing, and provides guidance on future investigations in the areas of stress reactivity and mental health. We propose that neuroendocrine perturbations of hypothalamus-pituitary-adrenal (HPA) axis and gene activity by epigenetic mechanisms may explain how early adverse circumstances may lead to post traumatic stress disorder (PTSD). The detailed exploration of the interaction of stress as environmental factor and epigenetic and genetic regulation in HPA axis may improve targeted interventions among vulnerable individuals. We are convinced that further studies following these directions will contribute to effective prevention and treatment of PTSD in early traumatized patients.


Subject(s)
Adverse Childhood Experiences , Stress Disorders, Post-Traumatic , Humans , Pituitary-Adrenal System , Hypothalamo-Hypophyseal System , Stress Disorders, Post-Traumatic/genetics , Stress Disorders, Post-Traumatic/psychology , Stress Disorders, Post-Traumatic/therapy , Stress, Psychological/genetics , Stress, Psychological/psychology
3.
Am J Drug Alcohol Abuse ; 47(6): 694-703, 2021 Nov 02.
Article in English | MEDLINE | ID: mdl-34582308

ABSTRACT

BACKGROUND: Alcohol use disorder (AUD) is one of the most serious public health problems worldwide. The OPRM1 and ALDH2 genes are important factors in the reward and alcohol metabolism pathways, and their DNA methylation patterns are closely related to AUD and are population-specific. Chinese Han people are the most populous ethnic group in the world, and this group experiences severe AUD. No epigenetic study on OPRM1 and ALDH2 has been performed in Chinese Han patients with AUD. OBJECTIVES: To investigate whether methylation patterns of OPRM1 and ALDH2 are associated with susceptibility to AUD in Chinese Han males. METHODS: DNA methylation of the OPRM1 and ALDH2 promoters was studied in Chinese Han males with AUD in Yunnan Province (N = 50 controls, N = 90 individuals with AUD) using the bisulfite pyrosequencing method. RESULTS: In the AUD group, compared with the control group, OPRM1 was hypermethylated(p < .01) but there was no significant difference in the methylation level of ALDH2 (p > .05). 9 CpG sites of OPRM1 (p < .05) and 2 CpG sites of ALDH2 (p > .01) were hypermethylated. Smoking promoted AUD-mediated hypermethylation of OPRM1, in which 3 CpG sites showed significant hypermethylation (p < .01). Age had no significant effect on the DNA methylation levels of these two genes. CONCLUSIONS: Our study demonstrates that DNA hypermethylation of the OPRM1 and ALDH2 promoter regions is associated with an increased risk of AUD, which may help to explain the pathogenesis and progression of AUD.


Subject(s)
Alcoholism , DNA Methylation , Alcoholism/genetics , Aldehyde Dehydrogenase, Mitochondrial/genetics , China , DNA Methylation/genetics , Humans , Male , Promoter Regions, Genetic/genetics , Receptors, Opioid, mu/genetics
4.
ACS Omega ; 6(10): 6747-6756, 2021 Mar 16.
Article in English | MEDLINE | ID: mdl-33748588

ABSTRACT

An integrated after-treatment device model was established for our target engine based on the fluid simulation software (Converge), and simulation was performed to determine the NH3, temperature, and velocity uniformity at the front-end cross section of its SCR catalyst, urea deposition rate, liquid film mass of the mixer, and its positions under a low-load condition. Moreover, the structure of the mixer and injection pressure were optimized to improve the uniformity and reduce the liquid film mass. Our simulation results show the following facts: the liquid film is easily accumulated under a low-load condition and the structure of the mixer and the injection pressure significantly affect the urea deposition rate and uniformities and accumulation masses of the liquid film. As a result, our final optimization results indicate that the mass of the NH3 and the NH3 uniformity at the front-end cross section of the SCR catalyst increase by 2.83 times and 5.65%. The urea deposition rate and the cumulative mass of the liquid film fall by 4.82 and 10.4%, respectively. This study has certain theoretical guiding significance for the optimal design of this type of after-treatment devices.

5.
Sci Rep ; 8(1): 16514, 2018 11 08.
Article in English | MEDLINE | ID: mdl-30410073

ABSTRACT

Sheep colibacillosis is one of the most common bacterial diseases found at large-scale sheep farms. The aim of this study was to employ RNA-seq to screen differentially expressed (DE) long non-coding RNAs (lncRNAs) that impart antagonistic or sensitive effects on Escherichia coli F17. In this study, individuals who had antagonistic or sensitive responses to E. coli F17 were identified by feeding E. coli F17 strains to Hu lambs. The sensitive group had higher levels of intestinal bacteria than that in the antagonistic group (P < 0.05), the jejunum showed various levels of mucosal tissue damage and had a dark colour, and disintegration of part of the small intestinal villi was observed. Totals of 34 DE lncRNAs and 703 DE mRNAs in two groups were identified. qRT-PCR results for 12 randomly selected DE lncRNAs and DE mRNAs were consistent with the RNA-seq data. Gene Ontology (GO), KEGG Pathway enrichment and lncRNA-mRNA interaction analyses identified 6 co-expressed genes, namely, MYO1G, TIMM29, CARM1, ADGRB1, SEPT4, and DESI2. This is the first study that has performed expression profiling of lncRNAs in the spleen of antagonistic and sensitive lambs. The identification of DE lncRNAs can facilitate investigations into the molecular mechanism underlying resistance to diarrhoea in sheep.


Subject(s)
Escherichia coli Infections/veterinary , Escherichia coli/pathogenicity , Gene Expression Profiling/veterinary , RNA, Long Noncoding/genetics , Sheep Diseases/genetics , Spleen/chemistry , Animals , Escherichia coli/classification , Escherichia coli Infections/genetics , Escherichia coli Infections/microbiology , Gene Expression Regulation , Gene Ontology , Gene Regulatory Networks , RNA, Messenger/genetics , Sequence Analysis, RNA/veterinary , Sheep , Sheep Diseases/microbiology , Spleen/microbiology
6.
Biochem Biophys Res Commun ; 506(4): 1026-1031, 2018 12 02.
Article in English | MEDLINE | ID: mdl-30404731

ABSTRACT

Coronary heart disease is the second highest specific cause of death. H9c2 cardiomyocytes were subjected to hypoxia (1% O2) for 0, 6, 12, 24 and 48 h. Cell apoptosis and the activity of caspase3/7 was detected using ELISA; western blot was applied to determine the cleaved-caspase3 (c-caspase3), cleaved-PARP (c-PARP) and cytochrome C (Cyto C) expression after the inhibitor negative control (in-NC), miR-503 inhibitor, mimic negative control (mi-NC) and miR-503 mimic were transfected into cells for 48 h. Moreover, flow cytometry was applied to evaluate mitochondrial membrane potential. In addition, luciferase reporter gene assay was used for detection the relationship between miR-503 and insulin-like growth-factor-1 receptor (IGF-1R). Real-time PCR showed microRNA-503 (miR-503) was elevated in a time-dependent manner under hypoxia. MiR-503 inhibition prevented cell apoptosis and reduced caspase3/7 activity and the expression of c-caspase3 and c-PARP, prevented mitochondrial membrane potential collapse and reduced the cyto C level in cytosol. While, miR-503 overexpression showed a pro-apoptotic role and resulted in mitochondrial membrane potential loss. MiR-503 directly targets IGF-1R in H9c2 cardiomyocytes. The depletion of IGF-1R using a specific IGF-1R siRNA (siIGF-1R) abolished anti-apoptotic function of miR-503 inhibitor, and LY294002 showed a similar trend. In summary, miR-503 promoted cell apoptosis, caused mitochondrial membrane potential collapse and the emancipation of cyto C from mitochondrial through PI3K/Akt pathway via targeting IGF-1R in H9c2 cardiomyocytes.


Subject(s)
Apoptosis/genetics , MicroRNAs/metabolism , Myocytes, Cardiac/metabolism , Myocytes, Cardiac/pathology , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Receptor, IGF Type 1/metabolism , Signal Transduction , Animals , Base Sequence , Cell Hypoxia/genetics , Cell Line , Cytochromes c/metabolism , Gene Expression Regulation , Membrane Potential, Mitochondrial , MicroRNAs/genetics , Rats , Receptor, IGF Type 1/genetics
7.
Sci Rep ; 8(1): 14524, 2018 09 28.
Article in English | MEDLINE | ID: mdl-30266913

ABSTRACT

Sheep colibacillosis is one of the most common bacterial diseases in large-scale sheep farms. In this study, we orally administered Escherichia coli F17 (E. coli F17) to lambs to obtain antagonistic and sensitive individuals. We used RNA-seq to screen for differential circRNAs in the spleens of both antagonist and sensitive individuals to explore the effect of circRNA on anti-diarrhoea in sheep. The results showed that 60 differentially expressed (DE) circRNAs were screened by RNA-seq in the spleen of antagonistic and sensitive lambs, among which 31 were up-regulated and 29 were down-regulated; q-PCR was used to validate the relative expression levels of six randomly selected circRNAs in antagonist and susceptible lambs and found to be consistent with the results of RNA-seq. Using Miranda analysis of circRNA-miRNA-mRNA interactions, we found a certain target relationship between 6 circRNAs, 5 miRNAs and 9 mRNAs. The relative expression levels of mRNA in antagonistic and sensitive lambs were verified by q-PCR and were consistent with the results of RNA-seq. This study explored the expression profile of circRNA in the spleen of an antagonistic and susceptible lamb with diarrhoea and found that differentially expressed circRNAs were helpful for determining how the lambs resist the pathogenesis of diarrhoea and provided a scientific basis for lambs to resist diarrhoea.


Subject(s)
Escherichia coli Infections/veterinary , Escherichia coli/physiology , RNA/genetics , Sheep Diseases/microbiology , Sheep/microbiology , Animals , Escherichia coli/isolation & purification , Escherichia coli Infections/genetics , Escherichia coli Infections/microbiology , MicroRNAs/genetics , RNA, Circular , RNA, Messenger/genetics , Sheep/genetics , Sheep Diseases/genetics , Spleen/metabolism , Spleen/microbiology , Transcriptome
8.
Transl Psychiatry ; 7(11): 2, 2018 03 09.
Article in English | MEDLINE | ID: mdl-29520063

ABSTRACT

Alcohol dependence is a worldwide problem with a great social and economic burden in many countries. A number of studies have suggested that BDNF (mature BDNF) and its precursor (proBDNF) play important roles in the alcohol dependence. However, what roles of the mBDNF/proBDNF pathways play during the pathological process of alcohol dependence are not clearly understood. In our clinical study, peripheral blood was sampled from 30 male patients with alcohol dependence and 50 healthy males (as control). The protein levels of proBDNF, p75NTR, sortilin, mBDNF, TrkB and mRNA levels of BDNF, p75NTR, sortilin, and TrkB were detected in the peripheral blood in our study. We found that the protein levels of proBDNF and p75NTR were increased, but not the sortilin protein level; while the TrkB protein level was decreased in the alcohol dependence patients compared with healthy controls. Moreover, the mRNA levels of p75NTR and sortilin from the lymphocytes were slightly increased; while BDNF and TrkB were significantly decreased. The ELISA results of mBDNF and TrkB were declined in the alcohol dependence group. The levels of mBDNF and TrkB were negatively correlated with the average amount of daily ethanol consumption, and the levels of proBDNF, p75NTR and sortilin were positively correlated with the average amount of ethanol consumption per day. The ratio of proBDNF to mBDNF was altered in alcohol dependence patients. The balance between the proBDNF/p75NTR and mBDNF/TrkB signalling pathways appeared dysregulated in alcohol dependence. Our results suggested that both pathways may participate in the complex processes of alcohol dependence.


Subject(s)
Adaptor Proteins, Vesicular Transport/blood , Alcoholism/blood , Brain-Derived Neurotrophic Factor/blood , Membrane Glycoproteins/blood , Nerve Tissue Proteins/blood , Protein Precursors/blood , Receptor, trkB/blood , Receptors, Nerve Growth Factor/blood , Signal Transduction , Adult , Humans , Male , Middle Aged , RNA, Messenger/blood
9.
RSC Adv ; 8(62): 35429-35436, 2018 Oct 15.
Article in English | MEDLINE | ID: mdl-35547892

ABSTRACT

Stretchable and flexible photoelectric materials are highly desirable for the development of artificial intelligence products. However, it remains a challenge to fabricate a stable, processable, and cost-efficient material with both high photoelectric sensitivity and remarkable deformability. Herein, a new kind of photoelectric sensitive, highly stretchable and environmentally adaptive materials was developed through in situ synthesis and π-π conjugation design. Specifically, a photoelectric elastomer zinc porphyrin SEBS(Zn-PorSEBS) was synthesized by introducing porphyrin to SEBS chain via a one-pot method. Then, graphene/zinc porphyrin SEBS (G/Zn-PorSEBS) composites were obtained by combing the elastomer with graphene sheets through solution blending. Notably, the resultant flexible composites were capable of capturing light changes with illumination on or off, and the maximum photocurrent density reached 0.13 µA cm-2. Moreover, the photoelectric composites exhibited a dramatic elongation (more than 1000%) and an excellent tensile strength about 20 MPa. This proposed strategy represents a general approach to manufacture photoelectric and flexible materials.

10.
PLoS One ; 12(5): e0176532, 2017.
Article in English | MEDLINE | ID: mdl-28464030

ABSTRACT

Hu sheep lambskin is a unique white lambskin from China that exhibits three types of flower patterns, including small waves, medium waves, and large waves, with small waves considered the best quality. However, our understanding of the molecular mechanism underlying flower pattern formation in Hu sheep lambskin is limited. The aim of the present study was to further explore the relevance between candidate microRNAs (miRNAs) and developmental characteristics of hair follicles and screen miRNAs for later functional validation. Herein, we employed Illumina Hiseq 2500 to identify differentially expressed miRNAs in hair follicles of different flower patterns with small, medium, and large waves to construct a comprehensive sequence database on the mechanism of hair follicle development. Paraffin sections of lambskin tissue were prepared to assess the structure of different hair follicles. Expression levels of candidate miRNAs in different flower patterns were analyzed by relative quantitation using real-time PCR, combined with histological observation and micro-observation technologies, and the correlation between expression levels of candidate miRNAs and histological properties of hair follicles was analyzed by using SPSS 17.0. A total of 522 differentially expressed miRNAs were identified, and RNA-seq analysis detected 7,266 target genes in different groups of flower patterns. Gene ontological analysis indicated these target genes were mainly involved in cell proliferation, differentiation, growth, apoptosis, and ion transport, and 14 miRNAs, including miR-143, miR-10a, and let-7 were screened as candidate miRNAs in Hu sheep hair follicle growth and development. In the same field of vision, variance analysis showed that the number of secondary follicles in small waves was significantly larger than that in large and medium waves (P<0.01); the diameter of the primary and secondary follicles in large waves was respectively larger than those in medium and small waves (P<0.01). Combined with correlation analysis between miRNA expression and histological properties of hair follicles, highly significant differences in miRNA-143 expression levels between large and small waves were observed (P<0.01), and significant differences in the miRNA-10a expression levels between large and small waves (P<0.05) and in let-7i expression levels between large and medium waves were observed (P<0.05). Significant differences in the expression of novel miRNAs of NW_004080184.1_6326 between medium and large waves were detected (P<0.05), and highly significant differences between medium and small waves were observed (P<0.01). Highly significant differences in the expression level of NW_004080165.1_8572 between medium and large and small waves (P<0.01), in that of NW_004080181.1_3961 between medium and small waves (P<0.01), and in that of NW_004080190.1_13733 between medium and large waves were observed, whereas no significant differences in the other miRNAs among large, medium, and small waves were detected. Overall, the present study showed that miRNA-143, miRNA-10a, let-7i, NW_004080184.1_6326, NW_004080165.1_8572, NW_004080181.1_3961, and NW_004080190.1_13733 could be considered as important candidate genes, indicating these seven miRNAs may play significant roles in hair follicle growth and development in Hu sheep lambskin.


Subject(s)
Hair Follicle/metabolism , MicroRNAs/metabolism , Sheep/metabolism , Animals , Gene Expression Regulation , Hair Follicle/anatomy & histology , MicroRNAs/genetics , MicroRNAs/physiology , Real-Time Polymerase Chain Reaction , Sheep/genetics
11.
J Nanosci Nanotechnol ; 17(1): 474-81, 2017 01.
Article in English | MEDLINE | ID: mdl-29624326

ABSTRACT

This paper described a one-step shell growth and extraordinarily facile method for the preparation of Ag nanoparticles-coated silica core­shell microspheres. The Ag nanoparticles could deposit on the silica microspheres to form continuous and compact shell layers at a balanced amount of polyvinyl pyrrolidone after the surface modification of the silica microspheres by (3-Mercaptopropyl) trimethoxysilane. The strong interactions between the thiol groups and Ag nanoparticles make it difficult to peel off the Ag shell from the core microspheres, obtaining extremely stable and homogeneous Ag nanoparticles-coated silica core­shell microspheres. Besides, the coating effect was controlled by varying the content of coupling agent, the type and amount of stabilizing agent, the quantity of silica microspheres as well as the mixing time between silica and silver ammonia solution. In addition, these Ag nanoparticles-coated silica core­shell microspheres were characterized using laser particle size analyzer (LPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The optical properties of the composite microspheres were observed by UV-vis spectroscopy.

12.
ACS Appl Mater Interfaces ; 8(36): 24131-42, 2016 Sep 14.
Article in English | MEDLINE | ID: mdl-27553528

ABSTRACT

Herein, light-weight and exceptionally conductive epoxy composite foams were innovatively fabricated for electromagnetic interference (EMI) shielding applications using multiwalled carbon nanotubes (MWCNTs) and 3D silver-coated melamine foam (SF) as conductive frameworks. A novel and nontraditional polymer microsphere was used to reduce the material density. The preformed, highly porous, and electrically conductive SF provided channels for fast electron transport. The MWCNTs were used to offset the decrease in conductive pathways due to the crystal defects of the silver layer and the insulating epoxy resin. Consequently, an exceptional conductivity of 253.4 S m(-1), a remarkable EMI shielding effectiveness of above 68 dB at 0.05-18 GHz, and a thermal conductivity of 0.305 W mK(-1) were achieved in these novel foams employing only 2 wt % of MWCNTs and 3.7 wt % of silver due to the synergistic effects that originated in the MWCNT and SF. These parameters are substantially higher than that achieved for the foam containing 2 wt % MWCNTs. Also, the SF exhibited little weakening in the foamability of the epoxy blends and the compression properties of resulting foams. All the results indicated that this effort provided a novel, simple, low-cost, and easily industrialized concept for fabricating light-weight, high-strength epoxy composite foams for high-performance EMI shielding applications.

13.
PLoS One ; 11(7): e0157463, 2016.
Article in English | MEDLINE | ID: mdl-27404636

ABSTRACT

Wave patterns in lambskin hair follicles are an important factor determining the quality of sheep's wool. Hair follicles in lambskin from Hu sheep, a breed unique to China, have 3 types of waves, designated as large, medium, and small. The quality of wool from small wave follicles is excellent, while the quality of large waves is considered poor. Because no molecular and biological studies on hair follicles of these sheep have been conducted to date, the molecular mechanisms underlying the formation of different wave patterns is currently unknown. The aim of this article was to screen the candidate microRNAs (miRNA) and genes for the development of hair follicles in Hu sheep. Two-day-old Hu lambs were selected from full-sib individuals that showed large, medium, and small waves. Integrated analysis of microRNA and mRNA expression profiles employed high-throughout sequencing technology. Approximately 13, 24, and 18 differentially expressed miRNAs were found between small and large waves, small and medium waves, and medium and large waves, respectively. A total of 54, 190, and 81 differentially expressed genes were found between small and large waves, small and medium waves, and medium and large waves, respectively, by RNA sequencing (RNA-seq) analysis. Differentially expressed genes were classified using gene ontology and pathway analyses. They were found to be mainly involved in cell differentiation, proliferation, apoptosis, growth, immune response, and ion transport, and were associated with MAPK and the Notch signaling pathway. Reverse transcription-polymerase chain reaction (RT-PCR) analyses of differentially-expressed miRNA and genes were consistent with sequencing results. Integrated analysis of miRNA and mRNA expression indicated that, compared to small waves, large waves included 4 downregulated miRNAs that had regulatory effects on 8 upregulated genes and 3 upregulated miRNAs, which in turn influenced 13 downregulated genes. Compared to small waves, medium waves included 13 downregulated miRNAs that had regulatory effects on 64 upregulated genes and 4 upregulated miRNAs, which in turn had regulatory effects on 22 downregulated genes. Compared to medium waves, large waves consisted of 13 upregulated miRNAs that had regulatory effects on 48 downregulated genes. These differentially expressed miRNAs and genes may play a significant role in forming different patterns, and provide evidence for the molecular mechanisms underlying the formation of hair follicles of varying patterns.


Subject(s)
Gene Expression Profiling , Hair Follicle/metabolism , MicroRNAs/genetics , Sheep/genetics , Animals , Gene Regulatory Networks , Hair Follicle/anatomy & histology , RNA, Messenger/genetics , Sheep/anatomy & histology
14.
Cancer Lett ; 356(2 Pt B): 367-73, 2015 Jan 28.
Article in English | MEDLINE | ID: mdl-25130170

ABSTRACT

TRIOBP isoforms 4 and 5 (TRIOBP-4/-5) are an actin-bundling protein associated with hearing loss. Here, we showed that TRIOBP-4/-5 was up-regulated in human pancreatic carcinoma cells. Knockdown of TRIOBP-4/-5 led to a loss of filopodia and a decrease in cell motility. Confocal microscopy showed that re-expression of GFP-TRIOBP-4 or -5 restored the filopodial formation in TRIOBP-4/-5-deficient PANC-1 cells. Finally, TRIOBP-4/-5 was shown to be overexpressed in human pancreatic cancer tissues. These results demonstrate a novel role of TRIOBP-4/-5 that promotes the motility of pancreatic cancer cells via regulating actin cytoskeleton reorganization in the filopodia of the cells.


Subject(s)
Actin Cytoskeleton/metabolism , Carcinoma, Pancreatic Ductal/pathology , Cell Movement , Microfilament Proteins/metabolism , Pancreatic Neoplasms/pathology , Pseudopodia/pathology , Blotting, Western , Carcinoma, Pancreatic Ductal/metabolism , Cell Proliferation , Humans , Microfilament Proteins/antagonists & inhibitors , Microfilament Proteins/genetics , Microscopy, Confocal , Pancreas/metabolism , Pancreatic Neoplasms/metabolism , Pseudopodia/metabolism , RNA, Small Interfering/genetics , Tumor Cells, Cultured , Up-Regulation , Wound Healing
15.
Sci Rep ; 4: 4907, 2014 May 09.
Article in English | MEDLINE | ID: mdl-24809456

ABSTRACT

Myosin 5c (Myo5c) is a low duty ratio, non-processive motor unable to move continuously along actin filaments though it is believed to participate in secretory vesicle trafficking in vertebrate cells. Here, we measured the ATPase kinetics of Myo5c dimers and tested the possibility that the coupling of two Myo5c molecules enables processive movement. Steady-state ATPase activity and ADP dissociation kinetics demonstrated that a dimer of Myo5c-HMM (double-headed heavy meromyosin 5c) has a 6-fold lower Km for actin filaments than Myo5c-S1 (single-headed myosin 5c subfragment-1), indicating that the two heads of Myo5c-HMM increase F-actin-binding affinity. Nanometer-precision tracking analyses showed that two Myo5c-HMM dimers linked with each other via a DNA scaffold and moved processively along actin filaments. Moreover, the distance between the Myo5c molecules on the DNA scaffold is an important factor for the processive movement. Individual Myo5c molecules in two-dimer complexes move stochastically in 30-36 nm steps. These results demonstrate that two dimers of Myo5c molecules on a DNA scaffold increased the probability of rebinding to F-actin and enabled processive steps along actin filaments, which could be used for collective cargo transport in cells.


Subject(s)
Actin Cytoskeleton/metabolism , Myosin Type V/metabolism , Protein Multimerization , Adenosine Diphosphate/metabolism , Adenosine Triphosphatases , DNA/metabolism , Enzyme Activation , Gene Expression , Humans , Hydrolysis , Kinetics , Myosin Type V/chemistry , Myosin Type V/genetics , Protein Binding , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism
16.
PLoS One ; 8(9): e74936, 2013.
Article in English | MEDLINE | ID: mdl-24069366

ABSTRACT

How myosin 10, an unconventional myosin, walks processively along actin is still controversial. Here, we used single molecule fluorescence techniques, TIRF and FIONA, to study the motility and the stepping mechanism of dimerized myosin 10 heavy-meromyosin-like fragment on both single actin filaments and two-dimensional F-actin rafts cross-linked by fascin or α-actinin. As a control, we also tracked and analyzed the stepping behavior of the well characterized processive motor myosin 5a. We have shown that myosin 10 moves processively along both single actin filaments and F-actin rafts with a step size of 31 nm. Moreover, myosin 10 moves more processively on fascin-F-actin rafts than on α-actinin-F-actin rafts, whereas myosin 5a shows no such selectivity. Finally, on fascin-F-actin rafts, myosin 10 has more frequent side steps to adjacent actin filaments than myosin 5a in the F-actin rafts. Together, these results reveal further single molecule features of myosin 10 on various actin structures, which may help to understand its cellular functions.


Subject(s)
Actins/chemistry , Actins/physiology , Myosins/chemistry , Myosins/physiology , Actin Cytoskeleton/chemistry , Actin Cytoskeleton/physiology , Actins/ultrastructure , Animals , Carrier Proteins/chemistry , Carrier Proteins/physiology , Microfilament Proteins/chemistry , Microfilament Proteins/physiology , Models, Biological , Rabbits
17.
Biochemistry ; 52(31): 5256-64, 2013 Aug 06.
Article in English | MEDLINE | ID: mdl-23789641

ABSTRACT

TRIOBP is an actin-bundling protein. Mutations of TRIOBP are associated with human deafness DFNB28. In vitro, TRIOBP isoform 4 (TRIOBP-4) forms dense F-actin bundles resembling the inner ear hair cell rootlet structure. Deletion of TRIOBP isoforms 4 and 5 leads to hearing loss in mice due to the absence of stereocilia rootlets. The mechanism of actin bundle formation by TRIOBP is not fully understood. The amino acid sequences of TRIOBP isoforms 4 and 5 contain two repeated motifs, referred to here as R1 and R2. To examine the potential role of R1 and R2 motifs in F-actin binding, we generated TRIOBP-4 mutant proteins deleted for R1 and/or R2, and then assessed their actin-binding activity and bundle formation in vitro using actin cosedimentation assays, and fluorescence and electron microscopy. Cellular distributions of the TRIOBP-4 mutants were examined by confocal microscopy. We showed that deletion of both R1 and R2 motifs completely disrupted the actin binding/bundling activities of TRIOBP-4 and impaired its localization to cellular actin cytoskeleton structures. By contrast, TRIOBP-4, lacking only R2 motif, retained its F-actin bundling ability and remained localized to actin filaments in cells, similar to full length TRIOBP-4. On the contrary, the R1 motif-deleted TRIOBP-4 mutant, which mainly consists of the R2 motif, formed thin F-actin bundles in vitro but failed to colocalize to actin filaments in cells. These results indicate that R1 motif is the major actin-binding domain of TRIOBP-4, and the binding of R2 motif with actin filaments is nonspecific.


Subject(s)
Actins/metabolism , Microfilament Proteins/chemistry , Microfilament Proteins/metabolism , Actin Cytoskeleton/metabolism , Amino Acid Motifs , Amino Acid Sequence , Animals , Mice , Microfilament Proteins/genetics , Molecular Sequence Data , Protein Binding , Protein Isoforms/chemistry , Protein Isoforms/genetics , Protein Isoforms/metabolism , Protein Transport
18.
Nanoscale Res Lett ; 7(1): 580, 2012 Oct 23.
Article in English | MEDLINE | ID: mdl-23092195

ABSTRACT

In this paper, based on the previous steps, a facile in situ reduction method was developed to controllably prepare polystyrene/Ag (PS/Ag) core-shell-shaped nanostructures. The crucial procedure includes surface treatment of polystyrene core particles by cationic polyelectrolyte polyethyleneimine, in situ formation of Ag nanoparticles, and immobilization of the Ag nanoparticles onto the surface of the polystyrene colloids via functional group NH from the polyethyleneimine. The experimental parameters, such as the reaction temperature, the reaction time, and the silver precursors were optimized for improvement of dispersion and Ag coat coverage of the core-shell-shaped nanostructures. Ultimately, the optimum parameters were obtained through a series of experiments, and well-dispersed, uniformly coated PS/Ag core-shell-shaped nanostructures were successfully fabricated. The formation mechanism of the PS/Ag core-shell-shaped nanostructures was also explained.

19.
Handb Exp Pharmacol ; 206: 163-88, 2011.
Article in English | MEDLINE | ID: mdl-21879450

ABSTRACT

In eukaryotes, mitochondria carry out numerous functions that are central to cellular and organismal health. How mitochondrial activities are regulated in response to differing environmental conditions, such as variations in diet, remains an important unsolved question in biology. Here, we review emerging evidence suggesting that reversible acetylation of mitochondrial proteins on lysine residues represents a key mechanism by which mitochondrial functions are adjusted to meet environmental demands. In mammals, three members of the sirtuin class of NAD(+)-dependent deacetylases - SIRT3, SIRT4, and SIRT5 - localize to mitochondria and regulate targets involved in a diverse array of biochemical pathways. The importance of this activity is highlighted by recent studies of SIRT3 indicating that this protein suppresses the emergence of diverse age-related pathologies: hearing loss, cardiac fibrosis, and malignancy. Together, these findings argue that mitochondrial protein acetylation represents a central means by which mammals regulate mitochondrial functions to maintain cellular and organismal homeostasis.


Subject(s)
Energy Metabolism , Mitochondria/enzymology , Mitochondrial Proteins/metabolism , Sirtuins/metabolism , Acetylation , Adaptation, Physiological , Aging/metabolism , Animals , Homeostasis , Humans , Lysine , Phenotype , Protein Processing, Post-Translational
20.
Yi Chuan ; 33(1): 48-53, 2011 Jan.
Article in Chinese | MEDLINE | ID: mdl-21377958

ABSTRACT

To explore the association of polymorphism in the serotonin transporter gene and the susceptibility to alcohol dependence in Yunnan Han population, PCR and DNA sequencing techniques were used to detect 5-HTT-linked promoter region (5-HTTLPR). One hundred and eighteen alcohol dependent patients as case group and 214 normal people as control group were employed in this study. Significant differences in genotype frequencies were present between case group and control group of 5-HTTLPR (P<0.05). The proportion of L/L and L/S genotype was significantly smaller in case group than that was in control group (OR=0.581, P=0.026). No significant association was observed in allelic frequencies, which differed in different ethnic groups. In conclusion, 5-HTTLPR polymorphism may be associated with alcohol dependent patients, and the genotype L/L or L/S may be a genetic factor that is responsible for decreasing susceptibility of alcohol dependence in Yunnan Han population.


Subject(s)
Alcoholism/genetics , Genetic Predisposition to Disease , Polymorphism, Genetic , Serotonin Plasma Membrane Transport Proteins/genetics , Adult , Aged , China/ethnology , Humans , Middle Aged , Promoter Regions, Genetic
SELECTION OF CITATIONS
SEARCH DETAIL
...