Search

Summary Adventitial progenitor cells, including SCA-1+ and mesenchymal stem cells, are believed to be important in vascular remodeling. It has been shown that SCA-1+ progenitor cells are involved in neointimal hyperplasia of vein grafts, but little is known concerning their involvement in hyperlipidemia-induced atherosclerosis. We employed single-cell sequencing technology on primary adventitial mouse SCA-1+ cells from wild-type and atherosclerotic-prone (ApoE-deficient) mice and found that a group of genes controlling cell migration and matrix protein degradation was highly altered. Adventitial progenitors from ApoE-deficient mice displayed an augmented migratory potential both in vitro and in vivo. This increased migratory ability was mimicked by lipid loading to SCA-1+ cells. Furthermore, we show that lipid loading increased miRNA-29b expression and induced sirtuin-1 and matrix metalloproteinase-9 levels to promote cell migration. These results provide direct evidence that blood cholesterol levels influence vascular progenitor cell function, which could be a potential target cell for treatment of vascular disease., Highlights • Hyperlipidemia affects migration of AdvSca-1+ cells • AdvSca-1+ ApoE KO cells show altered matrix of proteins • Decorin ameliorates extensive migration of AdvSca-1+ cells toward the neointima • MicroRNA-29 interferes with AdvSca-1+ migration via SIRT-1 and MMP-9, In this article, Xu and colleagues show that hyperlipidemia may confer to neointimal formation by extensive mobilization of adventitial progenitors. Using the ApoE KO murine model, they show that increased cholesterol levels augment adventitia progenitor migration, both in vitro and in vivo, through a modified matrix of proteins. Migratory capability could be ameliorated through mechanisms involving collagen formation and microRNA inhibition.

Lysin motivet (LysM) er et velkarakteriseret carbohydrat-bindende modul hvilken normalt findes som gentagende enheder i proteiner fra alle organismer, med undtagelse af Archaea. Den funktionelle betydning af denne multiplicitet blev undersøgt med udgangspunkt i to homologe endopeptidaser, Nlp/P60. Disse endopeptidasaer er involveret i peptidoglycan hydrolyse; Cell Wall Lytic Enzyme associated with cell Separation (CwlS) fra Bacillus subtilis og P60_Tth fra Thermus thermophilus. Biokemiske studier, foretaget med heterolog udtrykt CwlS, viste at flere LysM domæner opererer kooperativt for at binde N-acetylglukosamin (NAG) polymerer. Denne øgede affinitet korrelerede positivt med den katalytiske aktivitet af enzymet. Den kooperative ligand binding af LysM domænerne var yderligere demonstreret ved strukturelle studier på P60_2LysM, en variant af P60_Tth bestående af to LysM domæner og derved mangler det katalytiske domæne. Ligand induceret intermolekylær dimerisering blev observeret i co‑krystalstrukturen af P60_2LysM og NAG6. Indtil videre er dette det eneste strukturelle bevis der illustrerer intermolekylær dimerisering af LysM proteiner.Intermolekylær dimerisering af plante LysM receptor kinaser (RK) er blevet foreslået som initierings mekanismen foregåede down-stream signalering. Flere LysM-RK par er endog vist impliceret i symbiose- eller forsvarssignalering. Den ene partner i et LysM-RK par mangler normalt et aktivt kinase domæne og rekrutterer sandsynligvis en aktiv LysM-RK som co-receptor for at mediere down-stream signalering, eksempelvis nodfaktor receptorne 1 og 5 (NFR1 og NFR5) fra Lotus japonicus. Ved binding og genkendelse af rhizobiale nodfaktorer vil NFR1 og NFR5 initiere symbiosesignalering, hvilket fører til udviklingen af rodknolde og symbiotisk nitrogenfiksering. De fleste signaleringskomponenter i nodfaktor pathwayen er blevet identificeret via genetiske metoder. Den aktuelle signaleringsmodel mangler dog komponenter der kan koble genkendelse af nodfaktore ved plasmamembranen til down-stream responser som calcium influks og perinukleær calcium spiking, begge nødvendige for formationen af infektionstråde og rodknolde. Ved brug af nye proteomiske fremgangsmåder er ni receptor kinaser og fire receptor-lignede cytoplasmiske kinaser fundet i pull-down eksperimenter med NFR5 som receptor. Disse formodede interaktører bliver i øjeblikket valideret som komponenter af NFR5 signaleringskomplekset og deres funktionelle roller bliver karakteriseret. The Lysin Motif (LysM) is a well characterised carbohydrate-binding module that is present, usually as repeated entities, in proteins from all organisms except archaea. The functional significance of the multiplicity of the LysM module was investigated using two homologous NlpC/P60 endopeptidases involved in peptidoglycan hydrolysis; the Cell Wall Lytic enzyme associated with cell Separation (CwlS) from Bacillus subtilis, and P60_Tth from Thermus thermopiles. Biochemical studies conducted on purified CwlS showed that multiple LysM modules function cooperatively to bind N-acetylglucosamine (NAG) polymers, and that the increased affinity was positively correlated to the catalytic activity of the enzyme. The cooperativity of LysM domains was further demonstrated in structural studies on P60_2LysM, a variant of P60_Tth that contains only two LysM domains and lacks the catalytic domain. Ligand-induced intermolecular dimerization was observed in the co-crystal structure of P60_2LysM and NAG6. Until today, this is the only structural evidence illustrating intermolecular dimerization of LysM proteins.Intermolecular dimerization of plant LysM receptor kinases (RK) has been proposed as a mechanism for the initiation of downstream signalling. Indeed, several LysM-RK pairs have been reported to be implicated in symbiosis and defence signalling. One partner of the LysM-RK pair usually lacks an active kinase domain and most probably recruits the other active LysM-RK as a co-receptor to mediate downstream signalling. An example of such a LysM-RK pair is the Nod factor receptors 1 and 5 (NFR1 and NFR5) from Lotus japonicus. Upon recognition of rhizobial Nod factors, NFR1 and NFR5 initiate symbiosis signalling, subsequently leading to the development of root nodules and symbiotic nitrogen fixation. Most of the signalling components in the Nod factor signalling pathway have been identified through genetic approaches. The current symbiosis signalling model, however, lacks components that could link Nod factor perception at the plasma membrane to downstream responses, such as calcium influx and perinuclear calcium spiking events that are required for the formation of infection threads and nodules. Using a novel proteomics approach, nine receptor kinases and four receptor-like cytoplasmic kinases were found in pull-down experiments using an NFR5 bait. These putative interactors are currently being validated as components of the NFR5 signalling complex and their functional roles are being characterised.

Deciphering the extracellular signals that regulate SMC differentiation from stem cells is vital to further our understanding of the pathogenesis of vascular disease and for development of cell-based therapies and tissue engineering. Hyaluronan (HA) has emerged as an important component of the stem cell niche, however its role during stem cell differentiation is a complicated and inadequately defined process. This study aimed to investigate the role of HA in embryonic stem cell (ESC) differentiation toward a SMC lineage. ESCs were seeded on collagen-IV in differentiation medium to generate ESC-derived SMCs (esSMCs). Differentiation coincided with increased HA synthase (HAS) 2 expression, accumulation of extracellular HA and its assembly into pericellular matrices. Inhibition of HA synthesis by 4-methylumbelliferone (4MU), removal of the HA coat by hyaluronidase (HYAL) or HAS2 knockdown led to abrogation of SMC gene expression. HA activates ERK1/2 and suppresses EGFR signaling pathways via its principle receptor, CD44. EGFR inactivation coincided with increased binding to CD44, which was further augmented by addition of high molecular weight (HMW)-HA either exogenously or via HAS2 overexpression through adenoviral gene transfer. HMW-HA-stimulated esSMCs displayed a functional role in vascular tissue engineering ex vivo, vasculogenesis in a matrigel plug model and SMC accumulation in neointimal lesions of vein grafts in mice. These findings demonstrate that HAS2-induced HA synthesis and organization drives ESC-SMC differentiation. Thus, remodeling of the HA microenvironment is a critical step in directing stem cell differentiation toward a vascular lineage, highlighting HA as a potential target for treatment of vascular diseases. Stem Cells 2016 Embryonic stem cell-derived smooth muscle cells (esSMCs) maintained in high molecular weight HA (HMW-HA) were mixed with embryonic stem cell-derived endothelial cells (esECs) and then added to a Matrigel plug before subcutaneous injection into a mouse. After 1 week the Matrigel plug was removed and sections were stained for endothelial marker CD31 (green). esSMCs were labelled with Vybrant (red) before implantation in order to be distinguished from esECs. Vybrant stained esSMCs interacted with esECs to form dense and robust tube-like structures. DAPI (blue). bar, 100 μm.

In major cancer centers, heavy patients load and multiple registration stations could cause significant wait time, and can be result in patient complains. Real-time patient journey data and visual display are useful tools in hospital patient queue management. This paper demonstrates how we capture patient queue data without deploying any tracing devices; and how to convert data into useful patient journey information to understand where interventions are likely to be most effective. During our system development, remarkable effort has been spent on resolving data discrepancy and balancing between accuracy and system performances. A web-based dashboard to display real-time information and a framework for data analysis were also developed to facilitate our clinics' operation. Result shows our system could eliminate more than 95% of data capturing errors and has improved patient wait time data accuracy since it was deployed.

The development of decellularised scaffolds for small diameter vascular grafts is hampered by their limited patency, due to the lack of luminal cell coverage by endothelial cells (EC) and to the low tone of the vessel due to absence of a contractile smooth muscle cells (SMC). In this study, we identify a population of vascular progenitor c-Kit+/Sca-1- cells available in large numbers and derived from immuno-privileged embryonic stem cells (ESCs). We also define an efficient and controlled differentiation protocol yielding fully to differentiated ECs and SMCs in sufficient numbers to allow the repopulation of a tissue engineered vascular graft. When seeded ex vivo on a decellularised vessel, c-Kit+/Sca-1-derived cells recapitulated the native vessel structure and upon in vivo implantation in the mouse, markedly reduced neointima formation and mortality, restoring functional vascularisation. We showed that Krüppel-like transcription factor 4 (Klf4) regulates the choice of differentiation pathway of these cells through β-catenin activation and was itself regulated by the canonical Wnt pathway activator lithium chloride. Our data show that ESC-derived c-Kit+/Sca-1-cells can be differentiated through a Klf4/β-catenin dependent pathway and are a suitable source of vascular progenitors for the creation of superior tissue-engineered vessels from decellularised scaffolds.

Objective To determine changes in the incidence of dementia between 1988 and 2015. Methods This analysis was performed in aggregated data from individuals >65 years of age in 7 population-based cohort studies in the United States and Europe from the Alzheimer Cohort Consortium. First, we calculated age- and sex-specific incidence rates for all-cause dementia, and then defined nonoverlapping 5-year epochs within each study to determine trends in incidence. Estimates of change per 10-year interval were pooled and results are presented combined and stratified by sex. Results Of 49,202 individuals, 4,253 (8.6%) developed dementia. The incidence rate of dementia increased with age, similarly for women and men, ranging from about 4 per 1,000 person-years in individuals aged 65–69 years to 65 per 1,000 person-years for those aged 85–89 years. The incidence rate of dementia declined by 13% per calendar decade (95% confidence interval [CI], 7%–19%), consistently across studies, and somewhat more pronouncedly in men than in women (24% [95% CI 14%–32%] vs 8% [0%–15%]). Conclusion The incidence rate of dementia in Europe and North America has declined by 13% per decade over the past 25 years, consistently across studies. Incidence is similar for men and women, although declines were somewhat more profound in men. These observations call for sustained efforts to finding the causes for this decline, as well as determining their validity in geographically and ethnically diverse populations.

Several studies have reported a decline in incidence of dementia which may have large implications for the projected burden of disease, and provide important guidance to preventive efforts. However, reports are conflicting or inconclusive with regard to the impact of gender and education with underlying causes of a presumed declining trend remaining largely unidentified. The Alzheimer Cohorts Consortium aggregates data from nine international population-based cohorts to determine changes in the incidence of dementia since 1990. We will employ Poisson regression models to calculate incidence rates in each cohort and Cox proportional hazard regression to compare 5-year cumulative hazards across study-specific epochs. Finally, we will meta-analyse changes per decade across cohorts, and repeat all analysis stratified by sex, education and APOE genotype. In all cohorts combined, there are data on almost 69,000 people at risk of dementia with the range of follow-up years between 2 and 27. The average age at baseline is similar across cohorts ranging between 72 and 77. Uniting a wide range of disease-specific and methodological expertise in research teams, the first analyses within the Alzheimer Cohorts Consortium are underway to tackle outstanding challenges in the assessment of time-trends in dementia occurrence.