Galectin-8 specificity to cells: from broad outside to fine inside

Glycobiology is the world of sugars: how they are made, what they look like, and what they do. Despite the importance of glycan structures in life, knowledge has been hampered due to their inherent complexity. Lectins are nature's way to decipher the intricate code held by glycans, which makes them important players in both normal and pathological physiology. A key to the understanding of lectins and their cellular effects lies in the basis of their carbohydrate specificity and the multivalent interactions occurring at a cell surface. Also in the design and synthesis of new drugs, either to be used as future tools in fruitful glycobiology experiments, or as effective therapeutics in the clinic, such information is very helpful. This thesis is aimed at investigating the fine specificity of the two carbohydrate recognition domains of a human lectin, galectin-8, and to relate this fine specificity with cell surface binding and induced cellular effects. In short, our experiments charted the individual ligand preference displayed by the two domains, in addition to explaining how the striking monovalent affinity for sialylated ?-galactosides, shown by the N-terminal domain, was achieved. Further, we showed that although cell surface binding of intact galectin-8 didn?t require the sialic acid binding ability of the N-terminal domain, intracellular targeting following endocytosis did

A Re-Appraisal of the Early Andean Human Remains from Lauricocha in Peru

The discovery of human remains from the Lauricocha cave in the Central Andean highlands in the 1960’s provided the first direct evidence for human presence in the high altitude Andes. The skeletons found at this site were ascribed to the Early to Middle Holocene and represented the oldest known population of Western South America, and thus were used in several studies addressing the early population history of the continent. However, later excavations at Lauricocha led to doubts regarding the antiquity of the site. Here, we provide new dating, craniometric, and genetic evidence for this iconic site. We obtained new radiocarbon dates, generated complete mitochondrial genomes and nuclear SNP data from five individuals, and re-analyzed the human remains of Lauricocha to revise the initial morphological and craniometric analysis conducted in the 1960’s. We show that Lauricocha was indeed occupied in the Early to Middle Holocene but the temporal spread of dates we obtained from the human remains show that they do not qualify as a single contemporaneous population. However, the genetic results from five of the individuals fall within the spectrum of genetic diversity observed in pre-Columbian and modern Native Central American populations

Massive migration from the steppe is a source for Indo-European languages in Europe

We generated genome-wide data from 69 Europeans who lived between 8,000-3,000 years ago by enriching ancient DNA libraries for a target set of almost four hundred thousand polymorphisms. Enrichment of these positions decreases the sequencing required for genome-wide ancient DNA analysis by a median of around 250-fold, allowing us to study an order of magnitude more individuals than previous studies and to obtain new insights about the past. We show that the populations of western and far eastern Europe followed opposite trajectories between 8,000-5,000 years ago. At the beginning of the Neolithic period in Europe, ~8,000-7,000 years ago, closely related groups of early farmers appeared in Germany, Hungary, and Spain, different from indigenous hunter-gatherers, whereas Russia was inhabited by a distinctive population of hunter-gatherers with high affinity to a ~24,000 year old Siberian6 . By ~6,000-5,000 years ago, a resurgence of hunter-gatherer ancestry had occurred throughout much of Europe, but in Russia, the Yamnaya steppe herders of this time were descended not only from the preceding eastern European hunter-gatherers, but from a population of Near Eastern ancestry. Western and Eastern Europe came into contact ~4,500 years ago, as the Late Neolithic Corded Ware people from Germany traced ~3/4 of their ancestry to the Yamnaya, documenting a massive migration into the heartland of Europe from its eastern periphery. This steppe ancestry persisted in all sampled central Europeans until at least ~3,000 years ago, and is ubiquitous in present-day Europeans. These results provide support for the theory of a steppe origin of at least some of the Indo-European languages of Europe

Phagocytosis of Streptococcus pyogenes by all-trans retinoic acid-differentiated HL-60 cells: roles of azurophilic granules and NADPH oxidase.

BACKGROUND: New experimental approaches to the study of the neutrophil phagosome and bacterial killing prompted a reassessment of the usefulness of all-trans retinoic acid (ATRA)-differentiated HL-60 cells as a neutrophil model. HL-60 cells are special in that they possess azurophilic granules while lacking the specific granules with their associated oxidase components. The resulting inability to mount an effective intracellular respiratory burst makes these cells more dependent on other mechanisms when killing internalized bacteria. METHODOLOGY/PRINCIPAL FINDINGS: In this work phagocytosis and phagosome-related responses of ATRA-differentiated HL-60 cells were compared to those earlier described in human neutrophils. We show that intracellular survival of wild-type S. pyogenes bacteria in HL-60 cells is accompanied by inhibition of azurophilic granule-phagosome fusion. A mutant S. pyogenes bacterium, deficient in M-protein expression, is, on the other hand, rapidly killed in phagosomes that avidly fuse with azurophilic granules. CONCLUSIONS/SIGNIFICANCE: The current data extend our previous findings by showing that a system lacking in oxidase involvement also indicates a link between inhibition of azurophilic granule fusion and the intraphagosomal fate of S. pyogenes bacteria. We propose that differentiated HL-60 cells can be a useful tool to study certain aspects of neutrophil phagosome maturation, such as azurophilic granule fusion

Ancient mitochondrial DNA provides high-resolution time scale of the peopling of the Americas

The exact timing, route, and process of the initial peopling of the Americas remains uncertain despite much research. Archaeological evidence indicates the presence of humans as far as southern Chile by 14.6 thousand years ago (ka), shortly after the Pleistocene ice sheets blocking access from eastern Beringia began to retreat. Genetic estimates of the timing and route of entry have been constrained by the lack of suitable calibration points and low genetic diversity of Native Americans. We sequenced 92 whole mitochondrial genomes from pre-Columbian South American skeletons dating from 8.6 to 0.5 ka, allowing a detailed, temporally calibrated reconstruction of the peopling of the Americas in a Bayesian coalescent analysis. The data suggest that a small population entered the Americas via a coastal route around 16.0 ka, following previous isolation in eastern Beringia for ~2.4 to 9 thousand years after separation from eastern Siberian populations. Following a rapid movement throughout the Americas, limited gene flow in South America resulted in a marked phylogeographic structure of populations, which persisted through time. All of the ancient mitochondrial lineages detected in this study were absent from modern data sets, suggesting a high extinction rate. To investigate this further, we applied a novel principal components multiple logistic regression test to Bayesian serial coalescent simulations. The analysis supported a scenario in which European colonization caused a substantial loss of pre-Columbian lineages

Intracellular sorting of galectin-8 based on carbohydrate fine specificity

Galectin-8 has two carbohydrate recognition domains (CRDs), both of which bind beta-galactosides, but have different. ne specificity for larger saccharides. Previously we found that both CRDs were needed for efficient cell surface binding and signaling by soluble galectin-8, but unexpectedly binding of the N-CRD to its best ligands, alpha 2-3-sialylated galactosides, was not needed. In search for another role for this. ne specificity, we now compared endocytosis of galectin-8 in Chinese hamster ovary (CHO) cells and in a mutant (Lec2) lacking sialylated glycans, by fluorescence microscopy. Galectin-8 was endocytosed in both cells by a non-clathrin and non-cholesterol dependent pathway, but surprisingly, the pathway after endocytosis differed dramatically. In wild type (wt) cells, galectin-8 was found along the plasma membrane, near the nucleus, and in small vesicles. In the Lec2 cells, galectin-8 was found in larger vesicles evenly spread in the cell, but not along the plasma membrane or near the nucleus. Agalectin-8 mutant with an N-CRD having reduced affinity to sialylated glycans and increased affinity for other glycans, gave a Lec2 like pattern in the wt CHO cells, but a wt pattern in the Lec2 cells. Moreover, the pattern of galectin-3 after endocytosis differed from that of both the wt and mutant galactin-8. These data clearly demonstrate a role of galectin. ne specificity for intracellular targeting

"We were all together"- families' experiences of the health-promoting programme - A Healthy Generation.

BACKGROUND: Healthy lifestyle habits, including physical activity (PA), are associated with a broad range of positive psychosocial and physical health benefits. However, there are challenges involved in reaching vulnerable groups in socioeconomically disadvantaged areas. There is a lack of research on family-based PA interventions, specifically considering psychosocial health. The purpose of this study was to explore how families experienced psychosocial aspects of health after participation in a family-based programme, A Healthy Generation. METHODS: A Healthy Generation is a health-promoting, family-based programme delivered in collaboration with local municipalities and sport associations in socioeconomically disadvantaged areas in Sweden. Families with children in grade 2 (8-9 years), including siblings, participate in health-promoting activities, including activity sessions, healthy meals, health information and parental support groups. Data was collected through interviews with parents and children (n = 23) from a controlled pilot trial of the programme. Interviews were audio recorded, transcribed and analysed using a phenomenological hermeneutical method. RESULTS: Three themes and seven sub-themes emerged. The themes were: "A sense of belonging", "Awareness of one's role as a parent" and "Inspiration towards new and healthier behaviours". In terms of A sense of belonging, participation in the programme was the families own free zone, where they also had the opportunity of being together with other families in the programme. For participants that were isolated and lacked a social network, their participation helped them towards social participation. During the programme, parents created an Awareness of one's role as a parent, with new insights on how to act as a parent and they also negotiated differences between each other. Participation in the programme contributed to Inspiration towards new and healthier behaviours such as experience-based insights and healthy lifestyle changes. CONCLUSIONS: This study highlights the importance of co-participation in family-based health-promoting programmes to enhance psychosocial health among families in socioeconomically disadvantaged areas. The results give new insights into participants' experiences of psychosocial aspects of health after participation in a family-based PA programme. This knowledge can contribute to the understanding of how to design health-promoting, family-based interventions to promote psychosocial health in socioeconomically disadvantaged areas. TRIAL REGISTRATION: ISRCTN ISRCTN11660938 . Retrospectively registered 23 September 2019

Effectiveness of a Family Intervention to Increase Physical Activity in Disadvantaged Areas-A Healthy Generation, a Controlled Pilot Study.

There are large social inequalities in health. The purpose of this study was to evaluate the effects of a family intervention on physical activity (PA) and sedentary time (ST) in children and their parents. In this controlled pilot study, all 8-9-year-old children from four schools from a socioeconomically disadvantaged area in Sweden were invited and 67 children and 94 parents were included. The intervention was run by a foundation in co-operation with the municipality. The 9-month program included: (1) activity sessions, (2) healthy meals, (3) health information and (4) parental support groups. PA was primary outcome and ST was secondary outcome, measured by accelerometry. In total, 40 of the children (60%) and 45 of the adults (50%) had at least one day of valid accelerometer data at both baseline and follow-up. Significant intervention effects for the whole group were found in total PA (p = 0.048, mean difference (MD) intervention/control 150 counts per minute) and in vigorous PA (p = 0.02, MD 8 min/day) during the weekends. There were no differences between groups in the other PA variables or ST. This pilot study shows that it is possible to influence PA in families from a disadvantaged area through a family program