Variable NK cell receptors and their MHC class I ligands in immunity, reproduction and human evolution
TL;DR: It is suggested that the evolution of a system of NK cell receptors for MHC-C molecules that is most elaborate in chimpanzees facilitated the development of the bigger brains that enabled archaic and modern humans to migrate out of Africa and populate other continents.
Abstract: Natural killer (NK) cells have roles in immunity and reproduction that are controlled by variable receptors that recognize MHC class I molecules. The variable NK cell receptors found in humans are specific to simian primates, in which they have progressively co-evolved with MHC class I molecules. The emergence of the MHC-C gene in hominids drove the evolution of a system of NK cell receptors for MHC-C molecules that is most elaborate in chimpanzees. By contrast, the human system of MHC-C receptors seems to have been subject to different selection pressures that have acted in competition on the immunological and reproductive functions of MHC class I molecules. We suggest that this compromise facilitated the development of the bigger brains that enabled archaic and modern humans to migrate out of Africa and populate other continents.
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TL;DR: A single-cell atlas of the maternal–fetal interface reveals the cellular organization of the decidua and placenta, and the interactions that are critical for placentation and reproductive success, and develops a repository of ligand–receptor complexes and a statistical tool to predict the cell–cell communication via these molecular interactions.
Abstract: During early human pregnancy the uterine mucosa transforms into the decidua, into which the fetal placenta implants and where placental trophoblast cells intermingle and communicate with maternal cells. Trophoblast-decidual interactions underlie common diseases of pregnancy, including pre-eclampsia and stillbirth. Here we profile the transcriptomes of about 70,000 single cells from first-trimester placentas with matched maternal blood and decidual cells. The cellular composition of human decidua reveals subsets of perivascular and stromal cells that are located in distinct decidual layers. There are three major subsets of decidual natural killer cells that have distinctive immunomodulatory and chemokine profiles. We develop a repository of ligand-receptor complexes and a statistical tool to predict the cell-type specificity of cell-cell communication via these molecular interactions. Our data identify many regulatory interactions that prevent harmful innate or adaptive immune responses in this environment. Our single-cell atlas of the maternal-fetal interface reveals the cellular organization of the decidua and placenta, and the interactions that are critical for placentation and reproductive success.
1,315 citations
TL;DR: The current evidence for the role of abnormal placentation and therole of placental factors such as the antiangiogenic factor, sFLT1 (soluble fms-like tyrosine kinase 1) in the pathogenesis of the maternal syndrome of preeclampsia is discussed.
Abstract: Hypertensive disorders of pregnancy-chronic hypertension, gestational hypertension, and preeclampsia-are uniquely challenging as the pathology and its therapeutic management simultaneously affect mother and fetus, sometimes putting their well-being at odds with each other. Preeclampsia, in particular, is one of the most feared complications of pregnancy. Often presenting as new-onset hypertension and proteinuria during the third trimester, preeclampsia can progress rapidly to serious complications, including death of both mother and fetus. While the cause of preeclampsia is still debated, clinical and pathological studies suggest that the placenta is central to the pathogenesis of this syndrome. In this review, we will discuss the current evidence for the role of abnormal placentation and the role of placental factors such as the antiangiogenic factor, sFLT1 (soluble fms-like tyrosine kinase 1) in the pathogenesis of the maternal syndrome of preeclampsia. We will discuss angiogenic biomarker assays for disease-risk stratification and for the development of therapeutic strategies targeting the angiogenic pathway. Finally, we will review the substantial long-term cardiovascular and metabolic risks to mothers and children associated with gestational hypertensive disorders, in particular, preterm preeclampsia, and the need for an increased focus on interventional studies during the asymptomatic phase to delay the onset of cardiovascular disease in women.
829 citations
TL;DR: Recent evidence that supports the idea that immunological responses at the receptive maternal–fetal interface are not simply suppressed but are instead highly dynamic is discussed.
Abstract: The comparison of the immunological state of pregnancy to an immunosuppressed host-graft model continues to lead research and clinical practice to ill-defined approaches. This Review discusses recent evidence that supports the idea that immunological responses at the receptive maternal-fetal interface are not simply suppressed but are instead highly dynamic. We discuss the crucial role of trophoblast cells in shaping not only the way in which immune cells respond to the invading blastocyst but also how they collectively react to external stimuli. We also discuss the role of the microbiota in promoting a tolerogenic maternal immune system and highlight how subclinical viral infections can disrupt this status quo, leading to pregnancy complications.
565 citations
TL;DR: Clinicians have added clarity to this diagnosis and identified defects in 3 genes that can cause NK cell deficiency, as well as some of the underlying biology.
Abstract: Natural killer (NK) cells are part of the innate immune defense against infection and cancer and are especially useful in combating certain viral pathogens. The utility of NK cells in human health has been underscored by a growing number of persons who are deficient in NK cells and/or their functions. This can be in the context of a broader genetically defined congenital immunodeficiency, of which there are more than 40 presently known to impair NK cells. However, the abnormality of NK cells in certain cases represents the majority immunologic defect. In aggregate, these conditions are termed NK cell deficiency. Recent advances have added clarity to this diagnosis and identified defects in 3 genes that can cause NK cell deficiency, as well as some of the underlying biology. Appropriate consideration of these diagnoses and patients raises the potential for rational therapeutic options and further innovation.
440 citations
Cites background from "Variable NK cell receptors and thei..."
...Although NK cells are triggered by a large number of activation receptors, they are restrained by an extensive family of inhibitory receptors that can be ligated by class I MHC.(10) The most well known in humans is that of the killer cell immunoglobulin-like receptor family....
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...Although NK cells are triggered by a large number of activation receptors, they are restrained by an extensive family of inhibitory receptors that can be ligated by class I MHC.10 The most well known in humans is that of the killer cell immunoglobulin-like receptor family....
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TL;DR: The scope for personalized antigen-specific disease prevention is evaluated, whereby harnessing HLA–ligand interactions for clinical benefit is becoming a realistic prospect.
Abstract: Fifty years since the first description of an association between HLA and human disease, HLA molecules have proven to be central to physiology, protective immunity and deleterious, disease-causing autoimmune reactivity. Technological advances have enabled pivotal progress in the determination of the molecular mechanisms that underpin the association between HLA genetics and functional outcome. Here, we review our current understanding of HLA molecules as the fundamental platform for immune surveillance and responsiveness in health and disease. We evaluate the scope for personalized antigen-specific disease prevention, whereby harnessing HLA–ligand interactions for clinical benefit is becoming a realistic prospect.
424 citations
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TL;DR: The results of an international collaboration to produce a high-quality draft sequence of the mouse genome are reported and an initial comparative analysis of the Mouse and human genomes is presented, describing some of the insights that can be gleaned from the two sequences.
Abstract: The sequence of the mouse genome is a key informational tool for understanding the contents of the human genome and a key experimental tool for biomedical research. Here, we report the results of an international collaboration to produce a high-quality draft sequence of the mouse genome. We also present an initial comparative analysis of the mouse and human genomes, describing some of the insights that can be gleaned from the two sequences. We discuss topics including the analysis of the evolutionary forces shaping the size, structure and sequence of the genomes; the conservation of large-scale synteny across most of the genomes; the much lower extent of sequence orthology covering less than half of the genomes; the proportions of the genomes under selection; the number of protein-coding genes; the expansion of gene families related to reproduction and immunity; the evolution of proteins; and the identification of intraspecies polymorphism.
6,643 citations
Max Planck Society1, Broad Institute2, University of California, Berkeley3, European Bioinformatics Institute4, National Institutes of Health5, University of Massachusetts Medical School6, Spanish National Research Council7, University of Washington8, University of Montana9, Croatian Academy of Sciences and Arts10, University of Oviedo11, University of Bonn12, Emory University13, University College Cork14, Harvard University15
TL;DR: The genomic data suggest that Neandertals mixed with modern human ancestors some 120,000 years ago, leaving traces of Ne andertal DNA in contemporary humans, suggesting that gene flow from Neand Bertals into the ancestors of non-Africans occurred before the divergence of Eurasian groups from each other.
Abstract: Neandertals, the closest evolutionary relatives of present-day humans, lived in large parts of Europe and western Asia before disappearing 30,000 years ago. We present a draft sequence of the Neandertal genome composed of more than 4 billion nucleotides from three individuals. Comparisons of the Neandertal genome to the genomes of five present-day humans from different parts of the world identify a number of genomic regions that may have been affected by positive selection in ancestral modern humans, including genes involved in metabolism and in cognitive and skeletal development. We show that Neandertals shared more genetic variants with present-day humans in Eurasia than with present-day humans in sub-Saharan Africa, suggesting that gene flow from Neandertals into the ancestors of non-Africans occurred before the divergence of Eurasian groups from each other.
3,575 citations
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TL;DR: The structure, function, and ligand specificity of the receptors responsible for NK cell recognition are reviewed and the role of EMT inNK cell recognition is reviewed.
Abstract: The integrated processing of signals transduced by activating and inhibitory cell surface receptors regulates NK cell effector functions. Here, I review the structure, function, and ligand specificity of the receptors responsible for NK cell recognition.
2,724 citations
TL;DR: All these mitochondrial DMAs stem from one woman who is postulated to have lived about 200,000 years ago, probably in Africa, implying that each area was colonised repeatedly.
Abstract: ▪ Abstract Several unique properties of human mitochondrial DNA (mtDNA), including its high copy number, maternal inheritance, lack of recombination, and high mutation rate, have made it the molecule of choice for studies of human population history and evolution. Here we review the current state of knowledge concerning these properties, how mtDNA variation is studied, what we have learned, and what the future likely holds. We conclude that increasingly, mtDNA studies are (and should be) supplemented with analyses of the Y-chromosome and other nuclear DNA variation. Some serious issues need to be addressed concerning nuclear inserts, database quality, and the possible influence of selection on mtDNA variation. Nonetheless, mtDNA studies will continue to play an important role in such areas as examining socio-cultural influences on human genetic variation, ancient DNA, certain forensic DNA applications, and in tracing personal genetic history.
2,631 citations
TL;DR: NK cells are now recognized to express a repertoire of activating and inhibitory receptors that is calibrated to ensure self-tolerance while allowing efficacy against assaults such as viral infection and tumor development.
Abstract: Natural killer (NK) cells were originally defined as effector lymphocytes of innate immunity endowed with constitutive cytolytic functions. More recently, a more nuanced view of NK cells has emerged. NK cells are now recognized to express a repertoire of activating and inhibitory receptors that is calibrated to ensure self-tolerance while allowing efficacy against assaults such as viral infection and tumor development. Moreover, NK cells do not react in an invariant manner but rather adapt to their environment. Finally, recent studies have unveiled that NK cells can also mount a form of antigen-specific immunologic memory. NK cells thus exert sophisticated biological functions that are attributes of both innate and adaptive immunity, blurring the functional borders between these two arms of the immune response.
2,280 citations