Membrane microdomains or lipid rafts are known to be highly dynamic and to act as selective signal transduction mediators that facilitate interactions between the cell's external and internal environments.Lipid ra...Membrane microdomains or lipid rafts are known to be highly dynamic and to act as selective signal transduction mediators that facilitate interactions between the cell's external and internal environments.Lipid rafts play an important mediating role in the biology of cancer:they have been found in almost all existing experimental cancer models,including colorectal cancer (CRC),and play key regulatory roles in cell migration,metastasis,cell survival and tumor progression.This paper explores the current state of knowledge in this field by highlighting some of the pioneering and recent lipid raft studies performed on different CRC cell lines and human tissue samples.From this literature review,it becomes clear that membrane microdomains appear to be implicated in all key intracellular signaling pathways for lipid metabolism,drug resistance,cell adhesion,cell death,cell proliferation and many other processes in CRC.All signal transduction pathways seem to originate directly from those peculiar lipid islands,thereby orchestrating the colon cancer cells' state and fate.As confirmed by recent animal and preclinical studies in different CRC models,continuing to unravel the structure and function of lipid rafts-including their associated complex signaling pathways-will likely bring us one step closer to better monitoring and treating of colon cancer patients.展开更多
PH(pleckstrin homology)domains are well known to bind membrane phosphoinositides with different specificities and direct PH domain-containing proteins to discrete subcellular compartments with assistances of alternati...PH(pleckstrin homology)domains are well known to bind membrane phosphoinositides with different specificities and direct PH domain-containing proteins to discrete subcellular compartments with assistances of alternative binding partners.PH domain-containing proteins have been found to be involved in a wide range of cellular events,including signalling,cytoskeleton rearrangement and vesicular trafficking.Here we showed that a novel PH domain-containing protein,PEPP2(also known as PLEKHA5),displays moderate phosphoinositide binding specificity.Full length PEPP2 was observed to variably associate with both the plasma membrane and microtubules.The membrane-associated PEPP2 nucleated at cell-cell contacts and the leading edge of migrating cells.Overexpression of PEPP2 increased membrane microviscosity,indicating a potential role for PEPP2 in regulating function of microtubule-dependent membrane functions.展开更多
The stimulatory effect of lysophosphatidylcholine (lyso_PC) on ATP and ρ_nitrophenyl phosphate (PNPP) hydrolysis by the plasma membrane H +_ATPase from soybean (Glycine max (L.) Merr.) hypocotyls was studied. Re...The stimulatory effect of lysophosphatidylcholine (lyso_PC) on ATP and ρ_nitrophenyl phosphate (PNPP) hydrolysis by the plasma membrane H +_ATPase from soybean (Glycine max (L.) Merr.) hypocotyls was studied. Results showed that lyso_PC stimulated the hydrolysis of ATP; ATP hydrolysis was enhanced dramatically when lyso_PC was within 0-0.03%, and increased slightly when lyso_PC was higher than 0.03%. At the concentration of 0.03%, lyso_PC stimulated ATP hydrolysis by 80.5%. Kinetics analysis showed that V max increased from 0.46 μmol P i·mg -1 protein·min -1 to 0.87 μmol P i·mg -1 protein·min -1 while K m increased from 0.88 mmol/L to 1.15 mmol/L under lyso_PC treatment. The optimum pH of ATP hydrolysis was shifted from 6.5 to 7.0 . Moreover, it was found lyso_PC enhanced the inhibition of ATP hydrolysis by hydroxylamine. In the presence of 200 mmol/L hydroxylamine, ATP hydrolysis was inhibited by 74.4%, while it was inhibited by 84.4% when treated with lyso_PC. However, PNPP hydrolysis and the inhibitory effect of vanadate were not affected by lyso_PC. The above results indicated that the kinase domain might be an action site or regulatory region of the C_terminal autoinhibitory domain in the plant plasma membrane H +_ATPase.展开更多
How membrane curvature influences lipid distribution is under intensive research. In this short report, after a brief review of recent studies, the results of our coarse-grained (CG) molecular dynamics simulations of ...How membrane curvature influences lipid distribution is under intensive research. In this short report, after a brief review of recent studies, the results of our coarse-grained (CG) molecular dynamics simulations of membranes with “hemifused ribbons” geometry are discussed. When membranes of a binary mixture of (dipalmitoyl-phosphatidylcholine (DPPC) / diol-eoyl-phosphatidylethanolamine (DOPE) were used, DOPE accumulated in the negatively curved region of the monolayer that formed as the proximal monolayers fused (i.e., cis leaflets). However, the enrichment was dependent on the presence of tethering molecules which kept the curvature high (the curvature radius of ~1 nm), placing the cis monolayers ~2-2.5 nm from each other. Simulations in which DOPE was replaced with dioleoyl-phosphatidylcholine (DOPC) showed an insignificant degree of DOPC accumulation, suggesting the importance of lateral interaction among DOPE molecules for the curvature sorting. The above composition was not close to a demixing point and our radial distribution function analysis suggested that the DOPE accumulation was not assisted by the lipid phase separation which has been shown to promote curvature-driven lipid sorting. Relevance of curvature-driven lipid sorting to biological membrane fusion is discussed.展开更多
This study describes the development of novel protocols extending the real-time ultrasonic reflectometry(UTDR) for the detection of membrane fouling in hollow fiber module during ultrafiltration(UF) of oily water trea...This study describes the development of novel protocols extending the real-time ultrasonic reflectometry(UTDR) for the detection of membrane fouling in hollow fiber module during ultrafiltration(UF) of oily water treatment. A specially designed acoustic sensor with a frequency of 2.5 MHz was used. The hollow fiber membranes used were polysulphone(PSf) UF membranes with MWCO 40 kDa. The wastewaters with three different oily concentrations of 100, 500 and 1 000 mg/L were investigated. Diesel oil was utilized as the primary foulant. The results show that the permeate flux declines with operation time and its value becomes lower with the increase of the oily concentration in wastewater. It is found that ultrasonic measurement can detect the fouling and cleaning processes. A new signal analysis protocol-ultrasonic reflected energy was developed. Ultrasonic reflected energy obtained indicates the deposition of oily layer as a function of operation time and its removal after cleaning. The overall flux decline is reasonably correlated with the changes in ultrasonic reflected energy. This research provides the evidence that the ultrasonic reflectometry technique is capable of monitoring membrane fouling and cleaning in hollow fiber modules.展开更多
Platelets have essential roles in both health and disease. Normal platelet function is required for hemostasis.Inhibition of platelet function in disease or by pharmacological treatment results in bleeding disorders.O...Platelets have essential roles in both health and disease. Normal platelet function is required for hemostasis.Inhibition of platelet function in disease or by pharmacological treatment results in bleeding disorders.On the other hand,hyperactive platelets lead to heart attack and stroke.Calcium is a major second messenger in platelet activation,and elevated intracellular calcium leads to hyperactive platelets.Elevated platelet calcium has been documented in hypertension and diabetes;both conditions increase the likelihood of heart attack and stroke. Thus,proper regulation of calcium metabolism in the platelet is extremely important.Plasma membrane Ca2+-ATPase(PMCA)is a major player in platelet calcium metabolism since it provides the only significant route for calcium efflux.In keeping with the important role of calcium in platelet function,PMCA is a highly regulated transporter.In human platelets,PMCA is activated by Ca2+/calmodulin,by cAMP-dependent phosphorylation and by calpain-dependent removal of the inhibitory peptide.It is inhibited by tyrosine phosphorylation and calpain-dependent proteolysis.In addition,the cellular location of PMCA is regulated by a PDZ-domain-dependent interaction with the cytoskeleton during platelet activation.Rapid regulation by phosphorylation results in changes in the rate of platelet activation,whereas calpain-dependent proteolysis and interaction with the cytoskeleton appears to regulate later events such as clot retraction.In hypertension and diabetes,PMCA expression is upregulated while activity is decreased, presumably due to tyrosine phosphorylation.Clearly,a more complete understanding of PMCA function in human platelets could result in the identification of new ways to control platelet function in disease states.展开更多
Apoptosis plays a pivotal role in the etiology or pathogenesis of numerous medical disorders, and thus, target- ing of apoptotic cells may substantially advance patient care. In our quest for novel low-molecular-weigh...Apoptosis plays a pivotal role in the etiology or pathogenesis of numerous medical disorders, and thus, target- ing of apoptotic cells may substantially advance patient care. In our quest for novel low-molecular-weight probes for apoptosis, we focused on the uncommon amino acid T-carboxyglutamic acid （Gla）, which plays a vital role in the binding of clotting factors to negatively charged phospholipid surfaces. Based on the alkyl-malonic acid motif of Gla, we have developed and now present ML-10 （2-（5-fluoro-pentyl）-2-methyl-malonic acid, MW=206 Da）, the pro- totypical member of a novel family of small-molecule detectors of apoptosis. ML-10 was found to perform selective uptake and accumulation in apoptotic cells, while being excluded from either viable or necrotic cells. ML-10 uptake correlates with the apoptotic hallmarks of caspase activation, Annexin-V binding and disruption of mitochondrial membrane potential. The malonate moiety was found to be crucial for ML-10 function in apoptosis detection. ML- 10 responds to a unique complex of features of the cell in early apoptosis, comprising irreversible loss of membrane potential, permanent acidification of cell membrane and cytoplasm, and preservation of membrane integrity. ML-10 is therefore the most compact apoptosis probe known to date. Due to its fluorine atom, ML-10 is amenable to radio- labeling with the lSF isotope, towards its potential future use for clinical positron emission tomography imaging of apoptosis.展开更多
Lipid rafts are sterol and sphingolipid rich membrane domains that possibly may play roles in multiple cellular processes. These domains are still the matter of debate and it is still unknown by which mechanism if any...Lipid rafts are sterol and sphingolipid rich membrane domains that possibly may play roles in multiple cellular processes. These domains are still the matter of debate and it is still unknown by which mechanism if any and organisms promote their formation. This study centers on the ease of in vitro formation of lipid rafts-like structures as it relates to the relative availability of sphingolipids, phospholipids, cholesterol, and membrane proteins. Following a 12 h incubation period, isolation and extraction of the lipid rafts-like assemblies, the composition of the structures was evaluated using HPLC. Cholesterol and sphingomyelin were detected at 206 nm and phosphatidylcholine was detected at 254 nm. Identification of lactose permease, a typical membrane protein, was done using FTIR. The thermal stability of the produced structures was also determined. Results show that the addition of cholesterol significantly increased both the amount of insoluble lipid rafts-like structures and their stability, and that the availability of a minimum amount of sphingolipid was necessary to produce larger amounts of more stable structures. However, the addition of phospholipids hindered the formation of lipid rafts-like assemblies and those formed were generally less stable.展开更多
AIM:To present the outcome of modified grid laser photocoagulation(GLP)in diffuse diabetic macular edema(DDME)in eyes without extrafoveal and/or vitreofoveal traction.METHODS:Inclusion criteria for the retrospective s...AIM:To present the outcome of modified grid laser photocoagulation(GLP)in diffuse diabetic macular edema(DDME)in eyes without extrafoveal and/or vitreofoveal traction.METHODS:Inclusion criteria for the retrospective study were DDME eyes of patients with typeⅡdiabetes mellitus that had≥4 months of follow-up following GLP.Only one eye per patient was analyzed.Using 3-D spectral-domain optical coherence tomography(3-D SDOCT),eyes that had either extrafoveal or vitreofoveal traction,or had been previously treated by an intravitreal medication(s)were excluded.Treated DDME eyes were divided into 4 groups:A)"Classic"DDME that involved the central macula;B)edema did not involve the macular center;C)eyes associated with central epiretinal membrane(ERM);D)DDME that was associated with macular capillary dropout≥2 disc-diameter(DD).RESULTS:GLP outcome in 35 DDME eyes after 4-24(mean,13.1±6.9)months was as follows:Group A)18eyes with"classic"DDME.Following one or 2(mean,1.2)GLP treatments,best-corrected visual acuity(BCVA)improved by 1-2 Snellen lines in 44.4%(8/18)of eyes,and worsened by 1 line in 11.1%(2/18).Central macular thickness(CMT)improved by 7%-49%(mean,26.6%)in77.8%(14/18)of eyes.Causes of CMT worsening(n=4)were commonly explainable,predominantly(n=3)associated with emergence of extrafoveal traction,5-9months post-GLP.Group B)GLP(s)in DDME that did not involve the macular center(n=6)resulted in improved BCVA by 1-2 lines in 2 eyes.However,the central macula became involved in the edema process after the GLP in 3(50%)eyes,associated with an emergence of extrafoveal traction in one of these eyes 4months following the GLP.Group C)GLP failed in all 5eyes associated with central ERM.Group D)GLP was of partial benefit in 2 of 6 treated eyes with macular capillary dropout≥2DD.CONCLUSION:Eyes with DDME that involved the macular center were found to achieve favourable outcomes after GLP(s)during mid-term follow-up,unless complicated pre-GLP or post-GLP by vltreoretinal interface abnormalities,often extrafoveal traction or ERM,or by capillary dropout≥2DD.Prospective studies with larger cohorts are required.展开更多
The glomerulonephritis disease is characterized by inflammation of glomeruli or small blood vessels in the kidney that causes kidney diseases. The reason of glomerulonephritis disease is to deposit the anti-GBM auto a...The glomerulonephritis disease is characterized by inflammation of glomeruli or small blood vessels in the kidney that causes kidney diseases. The reason of glomerulonephritis disease is to deposit the anti-GBM auto antibody in the glomerular basement membrane. The type IV collagen is the main component of glomerular basement membrane that has α3 chain of type (IV) collagen of non-collagenous domain which contains N-terminal 7S domain, a triple helical collagenous domain and C-terminal non-collagenous glomerular domain (NC1). The amino terminal of α3 (IV) NC1 that induces the Experimental Autoimmuno Glomerulonephritis (EAG) in rat model has been identified. The recombinant rat α3 (IV) NC1 antigen has nine amino acid spans that are consistent with antibody or T cell epitope that induces in EAG. The research is carried out on the recombinant rat α3 (IV) NC1 production, purification, quantification, and characterization. The circulation of anti-GBM antibody in glomerular basement membrane can be measured by the ELISA assay. In addition, the recombinant rat antigen is secreted in HEK293 cell supernatant that is purified by Anti-FLAG M2 monoclonal IgG antibody affinity column and characterized and quantified by SDS-PAGE gel electrophoresis and Western blotting techniques.展开更多
Kindlin-2 belongs to a subfamily of FERM domain con-taining proteins,which plays key roles in activating integrin transmembrane receptors and mediating cell adhesion.Compared to conventional FERM domains,kindlin-2 FER...Kindlin-2 belongs to a subfamily of FERM domain con-taining proteins,which plays key roles in activating integrin transmembrane receptors and mediating cell adhesion.Compared to conventional FERM domains,kindlin-2 FERM contains an inserted pleckstrin homology(PH)domain that specifically binds to phosphatidy-linositol(3,4,5)trisphosphate(PIP3)and regulates the kindlin-2 function.We have determined the crystal struc-ture of kindlin-2 PH domain at 1.9Åresolution,which reveals a conserved PH domain fold with a highly charged and open binding pocket for PIP3 head group.Structural comparison with a previously reported solution structure of kindlin-2 PH domain bound to PIP3 head group reveals that upon PIP3 insertion,there is a significant conformational change of both the highly positively charged loop at the entry of the PIP3 binding pocket and the entireβbarrel of the PH domain.We propose that such“induced-fit”type change is crucial for the tight binding of PIP3 to anchor kindlin-2 onto the membrane surface,thereby promoting its binding to integrins.Our results provide important structural insight into kindlin-2-mediated membrane anchoring and integrin activation.展开更多
基金Supported by The Australian Research Council through Linkage Infrastructure, Equipment and Facilities grants, No.LE0775598the ARC/NHMRC FABLS Research Network, No.RN0460002
文摘Membrane microdomains or lipid rafts are known to be highly dynamic and to act as selective signal transduction mediators that facilitate interactions between the cell's external and internal environments.Lipid rafts play an important mediating role in the biology of cancer:they have been found in almost all existing experimental cancer models,including colorectal cancer (CRC),and play key regulatory roles in cell migration,metastasis,cell survival and tumor progression.This paper explores the current state of knowledge in this field by highlighting some of the pioneering and recent lipid raft studies performed on different CRC cell lines and human tissue samples.From this literature review,it becomes clear that membrane microdomains appear to be implicated in all key intracellular signaling pathways for lipid metabolism,drug resistance,cell adhesion,cell death,cell proliferation and many other processes in CRC.All signal transduction pathways seem to originate directly from those peculiar lipid islands,thereby orchestrating the colon cancer cells' state and fate.As confirmed by recent animal and preclinical studies in different CRC models,continuing to unravel the structure and function of lipid rafts-including their associated complex signaling pathways-will likely bring us one step closer to better monitoring and treating of colon cancer patients.
基金sponsored by the Science Foundation of the Ministry of Education of China(51208011)the setup grant of Jinan University(51207016).
文摘PH(pleckstrin homology)domains are well known to bind membrane phosphoinositides with different specificities and direct PH domain-containing proteins to discrete subcellular compartments with assistances of alternative binding partners.PH domain-containing proteins have been found to be involved in a wide range of cellular events,including signalling,cytoskeleton rearrangement and vesicular trafficking.Here we showed that a novel PH domain-containing protein,PEPP2(also known as PLEKHA5),displays moderate phosphoinositide binding specificity.Full length PEPP2 was observed to variably associate with both the plasma membrane and microtubules.The membrane-associated PEPP2 nucleated at cell-cell contacts and the leading edge of migrating cells.Overexpression of PEPP2 increased membrane microviscosity,indicating a potential role for PEPP2 in regulating function of microtubule-dependent membrane functions.
文摘The stimulatory effect of lysophosphatidylcholine (lyso_PC) on ATP and ρ_nitrophenyl phosphate (PNPP) hydrolysis by the plasma membrane H +_ATPase from soybean (Glycine max (L.) Merr.) hypocotyls was studied. Results showed that lyso_PC stimulated the hydrolysis of ATP; ATP hydrolysis was enhanced dramatically when lyso_PC was within 0-0.03%, and increased slightly when lyso_PC was higher than 0.03%. At the concentration of 0.03%, lyso_PC stimulated ATP hydrolysis by 80.5%. Kinetics analysis showed that V max increased from 0.46 μmol P i·mg -1 protein·min -1 to 0.87 μmol P i·mg -1 protein·min -1 while K m increased from 0.88 mmol/L to 1.15 mmol/L under lyso_PC treatment. The optimum pH of ATP hydrolysis was shifted from 6.5 to 7.0 . Moreover, it was found lyso_PC enhanced the inhibition of ATP hydrolysis by hydroxylamine. In the presence of 200 mmol/L hydroxylamine, ATP hydrolysis was inhibited by 74.4%, while it was inhibited by 84.4% when treated with lyso_PC. However, PNPP hydrolysis and the inhibitory effect of vanadate were not affected by lyso_PC. The above results indicated that the kinase domain might be an action site or regulatory region of the C_terminal autoinhibitory domain in the plant plasma membrane H +_ATPase.
文摘How membrane curvature influences lipid distribution is under intensive research. In this short report, after a brief review of recent studies, the results of our coarse-grained (CG) molecular dynamics simulations of membranes with “hemifused ribbons” geometry are discussed. When membranes of a binary mixture of (dipalmitoyl-phosphatidylcholine (DPPC) / diol-eoyl-phosphatidylethanolamine (DOPE) were used, DOPE accumulated in the negatively curved region of the monolayer that formed as the proximal monolayers fused (i.e., cis leaflets). However, the enrichment was dependent on the presence of tethering molecules which kept the curvature high (the curvature radius of ~1 nm), placing the cis monolayers ~2-2.5 nm from each other. Simulations in which DOPE was replaced with dioleoyl-phosphatidylcholine (DOPC) showed an insignificant degree of DOPC accumulation, suggesting the importance of lateral interaction among DOPE molecules for the curvature sorting. The above composition was not close to a demixing point and our radial distribution function analysis suggested that the DOPE accumulation was not assisted by the lipid phase separation which has been shown to promote curvature-driven lipid sorting. Relevance of curvature-driven lipid sorting to biological membrane fusion is discussed.
基金Project supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry of China Projects(043612611, 05YFGDGX10000) supported by the Natural Science Foundation and Development Program of Science and Technology of Tianjin, China
文摘This study describes the development of novel protocols extending the real-time ultrasonic reflectometry(UTDR) for the detection of membrane fouling in hollow fiber module during ultrafiltration(UF) of oily water treatment. A specially designed acoustic sensor with a frequency of 2.5 MHz was used. The hollow fiber membranes used were polysulphone(PSf) UF membranes with MWCO 40 kDa. The wastewaters with three different oily concentrations of 100, 500 and 1 000 mg/L were investigated. Diesel oil was utilized as the primary foulant. The results show that the permeate flux declines with operation time and its value becomes lower with the increase of the oily concentration in wastewater. It is found that ultrasonic measurement can detect the fouling and cleaning processes. A new signal analysis protocol-ultrasonic reflected energy was developed. Ultrasonic reflected energy obtained indicates the deposition of oily layer as a function of operation time and its removal after cleaning. The overall flux decline is reasonably correlated with the changes in ultrasonic reflected energy. This research provides the evidence that the ultrasonic reflectometry technique is capable of monitoring membrane fouling and cleaning in hollow fiber modules.
文摘Platelets have essential roles in both health and disease. Normal platelet function is required for hemostasis.Inhibition of platelet function in disease or by pharmacological treatment results in bleeding disorders.On the other hand,hyperactive platelets lead to heart attack and stroke.Calcium is a major second messenger in platelet activation,and elevated intracellular calcium leads to hyperactive platelets.Elevated platelet calcium has been documented in hypertension and diabetes;both conditions increase the likelihood of heart attack and stroke. Thus,proper regulation of calcium metabolism in the platelet is extremely important.Plasma membrane Ca2+-ATPase(PMCA)is a major player in platelet calcium metabolism since it provides the only significant route for calcium efflux.In keeping with the important role of calcium in platelet function,PMCA is a highly regulated transporter.In human platelets,PMCA is activated by Ca2+/calmodulin,by cAMP-dependent phosphorylation and by calpain-dependent removal of the inhibitory peptide.It is inhibited by tyrosine phosphorylation and calpain-dependent proteolysis.In addition,the cellular location of PMCA is regulated by a PDZ-domain-dependent interaction with the cytoskeleton during platelet activation.Rapid regulation by phosphorylation results in changes in the rate of platelet activation,whereas calpain-dependent proteolysis and interaction with the cytoskeleton appears to regulate later events such as clot retraction.In hypertension and diabetes,PMCA expression is upregulated while activity is decreased, presumably due to tyrosine phosphorylation.Clearly,a more complete understanding of PMCA function in human platelets could result in the identification of new ways to control platelet function in disease states.
文摘Apoptosis plays a pivotal role in the etiology or pathogenesis of numerous medical disorders, and thus, target- ing of apoptotic cells may substantially advance patient care. In our quest for novel low-molecular-weight probes for apoptosis, we focused on the uncommon amino acid T-carboxyglutamic acid （Gla）, which plays a vital role in the binding of clotting factors to negatively charged phospholipid surfaces. Based on the alkyl-malonic acid motif of Gla, we have developed and now present ML-10 （2-（5-fluoro-pentyl）-2-methyl-malonic acid, MW=206 Da）, the pro- totypical member of a novel family of small-molecule detectors of apoptosis. ML-10 was found to perform selective uptake and accumulation in apoptotic cells, while being excluded from either viable or necrotic cells. ML-10 uptake correlates with the apoptotic hallmarks of caspase activation, Annexin-V binding and disruption of mitochondrial membrane potential. The malonate moiety was found to be crucial for ML-10 function in apoptosis detection. ML- 10 responds to a unique complex of features of the cell in early apoptosis, comprising irreversible loss of membrane potential, permanent acidification of cell membrane and cytoplasm, and preservation of membrane integrity. ML-10 is therefore the most compact apoptosis probe known to date. Due to its fluorine atom, ML-10 is amenable to radio- labeling with the lSF isotope, towards its potential future use for clinical positron emission tomography imaging of apoptosis.
文摘Lipid rafts are sterol and sphingolipid rich membrane domains that possibly may play roles in multiple cellular processes. These domains are still the matter of debate and it is still unknown by which mechanism if any and organisms promote their formation. This study centers on the ease of in vitro formation of lipid rafts-like structures as it relates to the relative availability of sphingolipids, phospholipids, cholesterol, and membrane proteins. Following a 12 h incubation period, isolation and extraction of the lipid rafts-like assemblies, the composition of the structures was evaluated using HPLC. Cholesterol and sphingomyelin were detected at 206 nm and phosphatidylcholine was detected at 254 nm. Identification of lactose permease, a typical membrane protein, was done using FTIR. The thermal stability of the produced structures was also determined. Results show that the addition of cholesterol significantly increased both the amount of insoluble lipid rafts-like structures and their stability, and that the availability of a minimum amount of sphingolipid was necessary to produce larger amounts of more stable structures. However, the addition of phospholipids hindered the formation of lipid rafts-like assemblies and those formed were generally less stable.
文摘AIM:To present the outcome of modified grid laser photocoagulation(GLP)in diffuse diabetic macular edema(DDME)in eyes without extrafoveal and/or vitreofoveal traction.METHODS:Inclusion criteria for the retrospective study were DDME eyes of patients with typeⅡdiabetes mellitus that had≥4 months of follow-up following GLP.Only one eye per patient was analyzed.Using 3-D spectral-domain optical coherence tomography(3-D SDOCT),eyes that had either extrafoveal or vitreofoveal traction,or had been previously treated by an intravitreal medication(s)were excluded.Treated DDME eyes were divided into 4 groups:A)"Classic"DDME that involved the central macula;B)edema did not involve the macular center;C)eyes associated with central epiretinal membrane(ERM);D)DDME that was associated with macular capillary dropout≥2 disc-diameter(DD).RESULTS:GLP outcome in 35 DDME eyes after 4-24(mean,13.1±6.9)months was as follows:Group A)18eyes with"classic"DDME.Following one or 2(mean,1.2)GLP treatments,best-corrected visual acuity(BCVA)improved by 1-2 Snellen lines in 44.4%(8/18)of eyes,and worsened by 1 line in 11.1%(2/18).Central macular thickness(CMT)improved by 7%-49%(mean,26.6%)in77.8%(14/18)of eyes.Causes of CMT worsening(n=4)were commonly explainable,predominantly(n=3)associated with emergence of extrafoveal traction,5-9months post-GLP.Group B)GLP(s)in DDME that did not involve the macular center(n=6)resulted in improved BCVA by 1-2 lines in 2 eyes.However,the central macula became involved in the edema process after the GLP in 3(50%)eyes,associated with an emergence of extrafoveal traction in one of these eyes 4months following the GLP.Group C)GLP failed in all 5eyes associated with central ERM.Group D)GLP was of partial benefit in 2 of 6 treated eyes with macular capillary dropout≥2DD.CONCLUSION:Eyes with DDME that involved the macular center were found to achieve favourable outcomes after GLP(s)during mid-term follow-up,unless complicated pre-GLP or post-GLP by vltreoretinal interface abnormalities,often extrafoveal traction or ERM,or by capillary dropout≥2DD.Prospective studies with larger cohorts are required.
文摘The glomerulonephritis disease is characterized by inflammation of glomeruli or small blood vessels in the kidney that causes kidney diseases. The reason of glomerulonephritis disease is to deposit the anti-GBM auto antibody in the glomerular basement membrane. The type IV collagen is the main component of glomerular basement membrane that has α3 chain of type (IV) collagen of non-collagenous domain which contains N-terminal 7S domain, a triple helical collagenous domain and C-terminal non-collagenous glomerular domain (NC1). The amino terminal of α3 (IV) NC1 that induces the Experimental Autoimmuno Glomerulonephritis (EAG) in rat model has been identified. The recombinant rat α3 (IV) NC1 antigen has nine amino acid spans that are consistent with antibody or T cell epitope that induces in EAG. The research is carried out on the recombinant rat α3 (IV) NC1 production, purification, quantification, and characterization. The circulation of anti-GBM antibody in glomerular basement membrane can be measured by the ELISA assay. In addition, the recombinant rat antigen is secreted in HEK293 cell supernatant that is purified by Anti-FLAG M2 monoclonal IgG antibody affinity column and characterized and quantified by SDS-PAGE gel electrophoresis and Western blotting techniques.
基金supported by the 973 Program of the Ministry of Science and Technology of China(Grant Nos.2011CB911101 and 2012CB910304).
文摘Kindlin-2 belongs to a subfamily of FERM domain con-taining proteins,which plays key roles in activating integrin transmembrane receptors and mediating cell adhesion.Compared to conventional FERM domains,kindlin-2 FERM contains an inserted pleckstrin homology(PH)domain that specifically binds to phosphatidy-linositol(3,4,5)trisphosphate(PIP3)and regulates the kindlin-2 function.We have determined the crystal struc-ture of kindlin-2 PH domain at 1.9Åresolution,which reveals a conserved PH domain fold with a highly charged and open binding pocket for PIP3 head group.Structural comparison with a previously reported solution structure of kindlin-2 PH domain bound to PIP3 head group reveals that upon PIP3 insertion,there is a significant conformational change of both the highly positively charged loop at the entry of the PIP3 binding pocket and the entireβbarrel of the PH domain.We propose that such“induced-fit”type change is crucial for the tight binding of PIP3 to anchor kindlin-2 onto the membrane surface,thereby promoting its binding to integrins.Our results provide important structural insight into kindlin-2-mediated membrane anchoring and integrin activation.
