Desensitization of the Neurokinin 1 Receptor Is Mediated by the Receptor Carboxy-Terminal Region, but Is Not Caused by Receptor Internalization

Abstract: The carboxy-terminal cytoplasmic regions of the rat neurokinin 1 (substance P) and neurokinin 2 (neurokinin A) receptors have been exchanged to determine if this region of the neurokinin 1 receptor is involved in its desensitization. When expressed at similar levels in stably transfected Chinese hamster ovary (CHO) cell lines, receptors containing the carboxy-terminal region of the neurokinin 1 receptor desensitized significantly more (as measured by reduction of the inositol 1,4,5-trisphosphate response) when preexposed for 1 min to 1 µ M neurokinin, indicating a role for the carboxy-terminal region of the neurokinin 1 receptor in its desensitization. Measurement of receptor internalization using radiolabeled neurokinins (0.3 n M ) indicated that ∼75–80% of the receptors were internalized in each cell line after 10 min at 37°C, with no observable correlation between neurokinin receptor desensitization and internalization. Measurement of loss of receptor surface sites for cell lines CHO NK1 and CHO NK1NK2 following exposure to 1 µ M substance P also indicated no obvious relationship between the percent desensitization and percent of receptors internalized. Also, two inhibitors of neurokinin 1 receptor internalization, phenylarsine oxide and hyperosmolar sucrose, did not inhibit neurokinin 1 receptor desensitization. The protein kinase inhibitors Ro 31-8220, staurosporine, and Zn²⁺ had no effect on neurokinin 1 receptor desensitization, indicating that the kinases affected by these agents are not rate-limiting in neurokinin 1 receptor desensitization in this system.     

Assembly of infectious Kaposi’s sarcoma-associated herpesvirus progeny requires formation of a pORF19 pentamer

Herpesviruses cause severe diseases particularly in immunocompromised patients. Both genome packaging and release from the capsid require a unique portal channel occupying one of the 12 capsid vertices. Here, we report the 2.6 Å crystal structure of the pentameric pORF19 of the γ-herpesvirus Kaposi’s sarcoma-associated herpesvirus (KSHV) resembling the portal cap that seals this portal channel. We also present the structure of its β-herpesviral ortholog, revealing a striking structural similarity to its α- and γ-herpesviral counterparts despite apparent differences in capsid association. We demonstrate pORF19 pentamer formation in solution and provide insights into how pentamerization is triggered in infected cells. Mutagenesis in its lateral interfaces blocked pORF19 pentamerization and severely affected KSHV capsid assembly and production of infectious progeny. Our results pave the way to better understand the role of pORF19 in capsid assembly and identify a potential novel drug target for the treatment of herpesvirus-induced diseases.

In herpesviruses, genome packaging and release from the capsid require a unique portal channel. Here, the authors have resolved the crystal structure of a pentameric KSHV pORF19 assembly and find that it resembles the herpesviral portal cap and provides insights how the viral genome is retained within the capsid.     

Genetic basis of a spontaneous mutation’s expressivity

Genetic background often influences the phenotypic consequences of mutations, resulting in variable expressivity. How standing genetic variants collectively cause this phenomenon is not fully understood. Here, we comprehensively identify loci in a budding yeast cross that impact the growth of individuals carrying a spontaneous missense mutation in the nuclear-encoded mitochondrial ribosomal gene MRP20. Initial results suggested that a single large effect locus influences the mutation’s expressivity, with 1 allele causing inviability in mutants. However, further experiments revealed this simplicity was an illusion. In fact, many additional loci shape the mutation’s expressivity, collectively leading to a wide spectrum of mutational responses. These results exemplify how complex combinations of alleles can produce a diversity of qualitative and quantitative responses to the same mutation.     

Molecular Characterization of a Nondemyelinating Variant of Daniel’s Strain of Theiler’s Virus Isolated from a Persistently Infected Glioma Cell Line

Wild-type Daniel’s strain of Theiler’s virus (wt-DA) induces a chronic demyelination in susceptible mice which is similar to multiple sclerosis. A variant of wt-DA (designated DA-P12) generated during the 12th passage of persistent infection of a G26-20 glioma cell line failed to persist and induce demyelination in SJL/J mice. To identify the determinants responsible for this change in phenotype, we sequenced the capsid coding sequence (nucleotides [nt] 2991 to 3994) and found three mutations in VP1: residues 99 (Gly to Ser), 100 (Gly to Asp), and 103 (Asn to Lys). To study the role of these mutations in neurovirulence and demyelination, we prepared a recombinant virus, DAP-1C-2A/DA, with replacement of wt-DA nt 2991 to 3994 with the corresponding region of DA-P12, and viruses with individual point mutations at VP1 residues 99(Ser), 100(Asp), and 103(Lys). DAP-1C-2A/DA and viruses with a mutation at VP1 residue 99 or 100 (but not 103) completely attenuated the ability of wt-DA to induce demyelination. Failure to induce demyelination was not due to a general failure in growth, since DA-P12 and other mutant viruses lysed L-2 cells in vitro as effectively as wt-DA. The change in disease phenotype was independent of the specific B- or T-cell immune recognition because a decrease in the neurovirulence of mutant viruses was observed in neonatal mice and immune-deficient RAG1 −/− mice. This difference in neurovirulence is not the complete explanation for the failure of DA-P12 to demyelinate, since virus with a mutation at residue 103(Lys) had decreased neurovirulence but did induce demyelination. Therefore, point mutation at VP1 residue 99 or 100 altered the ability of wt-DA to demyelinate, perhaps related to a disruption in interaction between virus and receptor on certain neural cells.     

Gender biased neuroprotective effect of Transferrin Receptor 2 deletion in multiple models of Parkinson’s disease

Alterations in the metabolism of iron and its accumulation in the substantia nigra pars compacta accompany the pathogenesis of Parkinson’s disease (PD). Changes in iron homeostasis also occur during aging, which constitutes a PD major risk factor. As such, mitigation of iron overload via chelation strategies has been considered a plausible disease modifying approach. Iron chelation, however, is imperfect because of general undesired side effects and lack of specificity; more effective approaches would rely on targeting distinctive pathways responsible for iron overload in brain regions relevant to PD and, in particular, the substantia nigra. We have previously demonstrated that the Transferrin/Transferrin Receptor 2 (TfR2) iron import mechanism functions in nigral dopaminergic neurons, is perturbed in PD models and patients, and therefore constitutes a potential therapeutic target to halt iron accumulation. To validate this hypothesis, we generated mice with targeted deletion of TfR2 in dopaminergic neurons. In these animals, we modeled PD with multiple approaches, based either on neurotoxin exposure or alpha-synuclein proteotoxic mechanisms. We found that TfR2 deletion can provide neuroprotection against dopaminergic degeneration, and against PD- and aging-related iron overload. The effects, however, were significantly more pronounced in females rather than in males. Our data indicate that the TfR2 iron import pathway represents an amenable strategy to hamper PD progression. Data also suggest, however, that therapeutic strategies targeting TfR2 should consider a potential sexual dimorphism in neuroprotective response.Subject terms: Metals, Ageing, Neurological disorders     

中国脊椎动物红色名录

正为全面评估中国野生脊椎动物濒危状况,环境保护部联合中国科学院于2013年启动了《中国生物多样性红色名录——脊椎动物卷》编制工作。通过这项工作,我们编制了《中国脊椎动物红色名录》。本次评估主要依据以下3个标准:(1)IUCN Red List Categories and Criteria(Version 3.1)(IUCN,2012a);(2)Guidelines for Using the IUCN Red List Categories and Criteria(Version 8.1)(IUCN Standards and Petitions Subcommittee,2010);(3)Guidelines for Application of IUCN Red List Criteria at Regional and National Levels(Version 4.0)(IUCN,2012b)。     

Theiler’s Virus Infection of Perforin-Deficient Mice

Theiler’s virus, a murine picornavirus, infects the central nervous systems of C57BL/6 mice and is cleared after approximately 10 days by a process which requires CD8⁺ cytotoxic T cells. We used perforin-deficient C57BL/6 mice to test the role of this protein in viral clearance. Perforin-deficient mice died from viral encephalomyelitis between days 12 and 18 postinoculation. They had high levels of viral RNA in their central nervous systems until the time of death. In contrast, viral RNA had disappeared by day 11 postinoculation in wild-type C57BL/6 mice. Cytotoxic T cells can kill infected cells by two main mechanisms: the secretion of the pore-forming protein perforin or the interaction of the Fas ligand with the apoptosis-inducing Fas molecule on the target cell. Our results demonstrate that clearance of Theiler’s virus from the central nervous system in C57BL/6 mice is perforin dependent.     

Distinct brain oscillatory responses for the perception and identification of one’s own body from other’s body

The body recognition process includes complex visual processing, the sensation, perception, and distinction stages of the stimulus. This study examined this process by using the time–frequency analysis of EEG signals and analyzed the obtained data by using the event-related oscillations method. This study aimed to examine the oscillatory brain responses and distinguish one’s own body from other’s body. In the present study, 17 young adults were included and the EEGs were recorded with 32 electrodes placed in different locations. Event-related power spectrum and phase-locking analyzes were performed. ITC and ERSP data were analyzed using 2 (condition) × 11 (location) × 2 (hemisphere) ANOVA Design. As we observed a prolonged response in the theta band in the grand averages, we included the time variable in the overall model. As a result, we found that the phase-locking and the event-related power spectrum of the theta response in recognizing one’s own body were higher when compared to the phase-locking and the event-related power spectrum of the theta response in recognizing others’ body (p < 0.05). When the time variable was included, the early theta response was more phase-locked and had a higher power spectrum compared to the late theta response (p < 0.05). As a result of the power spectrum analysis, the condition × hemisphere interaction effect in the beta band was higher in the left hemisphere regarding increased responses in recognizing one’s own body (p < 0.05). As a result of ITC, the main effect of the condition was higher in the recognition of the stimulus of one’s own body (p < 0.05). Finally, the theta oscillator response stood out in distinguishing one’s own body from other’s body. Similarly, the power spectrum in the beta response was higher in the left hemisphere, and this finding is consistent with the literature.     

Alterations and Mechanism of Gut Microbiota in Graves’ Disease and Hashimoto’s Thyroiditis

To explore the role of gut microbiota in Graves’ disease (GD) and Hashimoto’s thyroiditis (HT). Seventy fecal samples were collected, including 27 patients with GD, 27 with HT, and 16 samples from healthy volunteers. Chemiluminescence was used to detect thyroid function and autoantibodies (FT3, FT4, TSH, TRAb, TGAb, and TPOAb); thyroid ultrasound and 16S sequencing were used to analyze the bacteria in fecal samples; KEGG (Kyoto Encyclopedia of Genes and Genomes) and COG (Clusters of Orthologous Groups) were used to analyze the functional prediction and pathogenesis. The overall structure of gut microbiota in the GD and HT groups was significantly different from the healthy control group. Proteobacteria and Actinobacteria contents were the highest in the HT group. Compared to the control group, the GD and HT groups had a higher abundance of Erysipelotrichia, Cyanobacteria, and Ruminococcus_2 and lower levels of Bacillaceae and Megamonas. Further analysis of KEGG found that the “ABC transporter” metabolic pathway was highly correlated with the occurrence of GD and HT. COG analysis showed that the GD and HT groups were enriched in carbohydrate transport and metabolism compared to the healthy control group but not in amino acid transport and metabolism. Our data suggested that Bacillus, Blautia, and Ornithinimicrobium could be used as potential markers to distinguish GD and HT from the healthy population and that “ABC transporter” metabolic pathway may be involved in the pathogenesis of GD and HT.     

Structure of the SthK Carboxy-Terminal Region Reveals a Gating Mechanism for Cyclic Nucleotide-Modulated Ion Channels

Cyclic nucleotide-sensitive ion channels are molecular pores that open in response to cAMP or cGMP, which are universal second messengers. Binding of a cyclic nucleotide to the carboxyterminal cyclic nucleotide binding domain (CNBD) of these channels is thought to cause a conformational change that promotes channel opening. The C-linker domain, which connects the channel pore to this CNBD, plays an important role in coupling ligand binding to channel opening. Current structural insight into this mechanism mainly derives from X-ray crystal structures of the C-linker/CNBD from hyperpolarization-activated cyclic nucleotide-modulated (HCN) channels. However, these structures reveal little to no conformational changes upon comparison of the ligand-bound and unbound form. In this study, we take advantage of a recently identified prokaryote ion channel, SthK, which has functional properties that strongly resemble cyclic nucleotide-gated (CNG) channels and is activated by cAMP, but not by cGMP. We determined X-ray crystal structures of the C-linker/CNBD of SthK in the presence of cAMP or cGMP. We observe that the structure in complex with cGMP, which is an antagonist, is similar to previously determined HCN channel structures. In contrast, the structure in complex with cAMP, which is an agonist, is in a more open conformation. We observe that the CNBD makes an outward swinging movement, which is accompanied by an opening of the C-linker. This conformation mirrors the open gate structures of the K_v1.2 channel or MthK channel, which suggests that the cAMP-bound C-linker/CNBD from SthK represents an activated conformation. These results provide a structural framework for better understanding cyclic nucleotide modulation of ion channels, including HCN and CNG channels.     

Dipeptidyl peptidase 4 contributes to Alzheimer’s disease–like defects in a mouse model and is increased in sporadic Alzheimer’s disease brains

The amyloid cascade hypothesis, which proposes a prominent role for full-length amyloid β peptides in Alzheimer’s disease, is currently being questioned. In addition to full-length amyloid β peptide, several N-terminally truncated fragments of amyloid β peptide could well contribute to Alzheimer’s disease setting and/or progression. Among them, pyroGlu3–amyloid β peptide appears to be one of the main components of early anatomical lesions in Alzheimer’s disease–affected brains. Little is known about the proteolytic activities that could account for the N-terminal truncations of full-length amyloid β, but they appear as the rate-limiting enzymes yielding the Glu3–amyloid β peptide sequence that undergoes subsequent cyclization by glutaminyl cyclase, thereby yielding pyroGlu3–amyloid β. Here, we investigated the contribution of dipeptidyl peptidase 4 in Glu3–amyloid β peptide formation and the functional influence of its genetic depletion or pharmacological blockade on spine maturation as well as on pyroGlu3–amyloid β peptide and amyloid β 42–positive plaques and amyloid β 42 load in the triple transgenic Alzheimer’s disease mouse model. Furthermore, we examined whether reduction of dipeptidyl peptidase 4 could rescue learning and memory deficits displayed by these mice. Our data establish that dipeptidyl peptidase 4 reduction alleviates anatomical, biochemical, and behavioral Alzheimer’s disease–related defects. Furthermore, we demonstrate that dipeptidyl peptidase 4 activity is increased early in sporadic Alzheimer’s disease brains. Thus, our data demonstrate that dipeptidyl peptidase 4 participates in pyroGlu3–amyloid β peptide formation and that targeting this peptidase could be considered as an alternative strategy to interfere with Alzheimer’s disease progression.     

Portugal’s prominence in malaria research: How a small country became a key player in European research on one of the world’s deadliest diseases

Despite its limited resources, Portugal has gained a prominent position in research on malaria. Several historical and personal factors have contributed to this achievement. Subject Categories: S&S: Economics & Business, S&S: History & Philosophy of Science, Microbiology, Virology & Host Pathogen Interaction

Despite a significant increase that started during the 1990s, Portugal’s scientific production remains rather modest compared with the overall research output in the European Union (EU). However, the country’s achievements in malaria research are truly remarkable and, in relative terms, far above its EU neighbors in most relevant accounts. The factors to explain this accomplishment include the fact that malaria was autochthonous in Portugal until 1973; the country’s colonial history and its close ties with its former colonies; and several outstanding scientists who each inspired generations of malariologists.For most of the 20th century, research in Portugal was underfunded, and the country’s overall contribution to science was modest at best. This started to change when Portugal joined the European Union (then the European Economic Community) in 1985 and gained further momentum in the 1990s with the creation of a dedicated Ministry of Science. As a consequence, the Portuguese scientific production increased significantly in terms of the number of scientific articles published. Nevertheless, public funding for research has remained well below that of many other EU countries, and far from the target of 3% of the country’s GDP, which limits Portugal’s overall scientific output. Yet, there is one field of research where Portugal has been making significant contributions, even long before 1985: malaria.

… there is one field of research where Portugal has been making significant contributions, even long before 1985: malaria.

Among many other achievements, Portuguese laboratories have delivered important contributions to malaria research in areas as diverse as drug development, discovery and repurposing, genetic diversity of Plasmodium parasites, mechanisms of drug resistance, co‐infection between Plasmodium and other parasites, host–Plasmodium interactions, nutrient sensing and acquisition by malaria parasites, modulation of Plasmodium liver infection, immune and inflammatory responses to Plasmodium infection, diagnosis, vaccines, the role of microbiota on malaria transmission, pathogenesis of placental and cerebral malaria and acute lung injury, mechanisms of tolerance to malaria, malaria epidemiology, and vector genetics (see Further Reading for examples). Portugal’s percentage of scientific papers published in the field of malaria during the past decade relative to the total number of published articles is the highest in the EU (Fig 1A). Naturally, Portugal cannot compete with larger or more affluent countries in terms of the absolute numbers of articles published on malaria. Yet, the country ranks 5^th in this regard, closely following the Netherlands, Belgium, Sweden, and Denmark, four countries that have been investing much more and much longer in scientific research (Fig 1B). In fact, if one takes into account the funding for R&D in the EU nations, Portugal ranks ahead of every other country in terms of the number of malaria papers published relative to the investment made in science at the national level (Fig 1C).Open in a separate windowFigure 1Malaria research in Portugal and in the EU(A) Percentage of papers on the subject of malaria relative to the total number of papers from each of the indicated countries from 2009 to present. (B) Number of malaria research articles per 1,000 researchers in each of the indicated countries. (C) Number of malaria research articles per 100,000 Euros of gross domestic expenditure on R&D in each of the indicated countries. Total R&D personnel and intramural R&D expenditure data are from 2017. Papers were quantified through searches of PubMed for articles with affiliation to each of the indicated countries, published from 2009 to present, by use of the terms “malaria” or “Plasmodium”. Data on R&D investments from Eurostat.This raises the question of why Portugal, a rather small country with only a few decades of research history and an overall moderate scientific performance, fares relatively so well when it comes to research on malaria. I argue that there are three independent, albeit interrelated factors to explain this feat.A lasting reality demanding an appropriate responseThe first factor was the presence of autochthonous malaria in Portugal until the second half of the 20th century and the establishment of research institutions largely dedicated to studying and fighting the disease. Until the end of the World War II, malaria was endemic throughout much of Southern Europe; Italy, Greece, and Portugal were particularly affected. From 1955 to 1969, the WHO conducted its Global Malaria Eradication Programme, which successfully eliminated malaria in several regions of the world, including Southern Europe. The specific history of malaria eradication in Portugal is described in great detail by Bruce‐Chwatt (Bruce‐Chwatt, 1977) and highlights the intense efforts by multiple state‐sponsored institutions dedicated to studying and combating the disease.Even before the war, in 1931, the Malaria Research Station (Estação Experimental de Combate ao Sezonismo, EECS) was created in Benavente, the goals of which included the collection and analysis of blood samples from infected individuals, treatment of malaria patients, identification of mosquito populations, and malaria prophylaxis. In 1938, the Malaria Institute (Instituto de Malariologia, iMal) was founded in Águas de Moura to investigate the epidemiology of the disease, promoting adequate treatment and implementing vector control measures (Saavedra, 2010). Nonetheless, it was not until 1973 that malaria was eventually eliminated in Portugal, three years after Italy, and only one year before Greece.

… it was not until 1973 that malaria was eventually eliminated in Portugal, three years after Italy, and only one year before Greece.

Yet, the threat of malaria reemergence meant ongoing vigilance, and iMal paved the way for the creation of the Centre for the Study of Malaria and Parasitology (Centro de Estudos de Malária e Parasitologia), in 1973, later to become the Centre for the Study of Zoonoses (Centro de Estudos de Zoonoses) in 1987, and the Centre for Vector and Infectious Disease Studies (Centro de Estudos de Vetores e Doenças Infeciosas) in 1993. In addition, the Portuguese School of Tropical Medicine (later called National School of Public Health and Tropical Medicine, ENSPMT, now the Institute of Tropical Medicine and Hygiene, IHMT), founded in 1902, was one of only four institution of its kind in the world (Amaral, 2008). Since its inception, its mission has been the teaching and research in tropical medicine, biomedical sciences, and international health and, to this day, a significant part of its research continues to focus on malaria.A close bond with AfricaAnother major factor for Portugal’s prominent position in malaria research is its colonial past and the country’s close ties with its former colonies. During its period of maritime expansion in the 15^th and 16^th centuries, Portugal colonized many territories from Asia to the Americas and Africa. Most, if not all, of these territories were, and for a large part still are, endemic for malaria. Former colonies, such as Brazil or the Portuguese territories in India, gained their independence during the 19^th century, but maintained close ties with Portugal.However, several African countries, specifically Angola, Cape Verde, Guinea‐Bissau, Mozambique, and S. Tomé & Príncipe, remained under Portuguese rule until well into the second half of the 20^th century (Miller, 1975). In fact, while most African nations gained their independence from European countries during the 1950s and 1960s, Portugal’s dictatorship held on to and suppressed its African overseas territories, which led to armed uprisings in Angola and Guinea‐Bissau in 1961, and in Mozambique in 1964 (Miller, 1975). During the ensuing colonial wars, thousands of Portuguese soldiers were sent to these countries, where they were exposed not only to the horrors of war, but also to malaria (Campos, 2017). The Portuguese military actions in Africa finally came to an end in 1974 after the peaceful Carnation Revolution, which established democracy in Portugal and ended the colonization of all Portuguese‐held African territories.Over the next few years, hundreds of thousands of military personnel and former residents of the ex‐colonies, known as “retornados”, moved back to Portugal, leading to an increase in the number of imported malaria cases (Bruce‐Chwatt, 1977). Since then, these numbers have subsided, but the close ties that Portugal maintains with its former colonies mean that travel to and from malaria‐endemic regions remains high, contributing to the prevalence of imported malaria cases (Piperaki, 2018). It also means that malaria is not such a distant threat for most Portuguese; even today, many younger people have direct contact with family members or friends who have experienced malaria, bringing the reality of this scourge closer to home than in many other EU countries.

… even today, many younger people have direct contact with family members or friends who have experienced malaria, bringing the reality of this scourge closer to home than in many other EU countries.

Remarkable and inspiring figuresThe third and final factor is the enormous and lasting influence of various uniquely inspiring figures from several generations of malaria researchers. Indeed, the history of Portuguese malaria research is rich in prominent scientists who shaped the national research landscape. Attempting to highlight specific names among the many doctors, epidemiologists, and scientists from the past and present is a naturally risky exercise that runs the risk of overlooking important figures. Nevertheless, the crucial contribution of a few representatives of four generations of Portuguese scientists is beyond dispute.Ricardo Jorge (1858–1939) was a renowned epidemiologist responsible for the 1899–1901 National Sanitary Plan, which marked the introduction of modern sanitary concepts in Portugal and changed national public health. In 1903, Jorge was the first to collect reliable and extensive data on the incidence of malaria and its seasonal distribution (JORGE, 1903). He was Portugal’s Health Inspector‐General from 1899 to 1926, succeeded by José Alberto de Faria (1888–1958), another key figure who, with the support of the Rockefeller Foundation (Saavedra, 2014), created the EECS in Benavente, the first step for advancing knowledge about malaria in Portugal (Bruce‐Chwatt, 1977).Well within the 20^th century, Francisco Cambournac (1903–1994) and Fausto Landeiro (1896–1949) were arguably the most important contributors to Portuguese malariology during that period. Following extensive training in some of the most reputed parasitology schools in Europe, Cambournac became Director of Benavente’s EECS in 1933, and Landeiro occupied that position from 1938 to 1949. Cambournac founded the iMal in Águas de Moura, serving as its Director from 1939 to 1954, and became Director of the WHO’s African region from 1954 to 1964 (Lobo, 2012).Cambournac and Landeiro published extensively on the epidemiology, entomology, and control of malaria during the 1930s and 1940s, and gave a comprehensive account of the status of the disease in Portugal during that period. Cambournac’s 237‐page long review (Cambournac, 1942) provided all the epidemiological and other data needed for future planning of control and eradication of malaria in the country, the success of which is widely acknowledged to his immense work (Bruce‐Chwatt, 1977).During the 1960s and early 1970s, the National School of Public Health and Tropical Medicine, ENSPMT, now the Institute of Tropical Medicine and Hygiene, IHMT, played an important role not only in Portuguese research on malaria and other tropical diseases, but also in the cooperation with Portugal’s overseas territories at the time. The 1974 revolution and the decolonization in Africa led to a reshaping of this cooperation, which became increasingly centered on reinforcing the newly independent countries’ health systems, on their capacity to carry out research on endemic diseases, and on training programs in tropical and preventive medicine (Havik, 2015). Virgílio do Rosário, professor at the IHMT and, later, head of the Institute’s Centre for Malaria and Other Tropical Diseases (CMDT), played a pivotal role in this process. Do Rosário was the founder of several national and international networks for studying malaria and neglected diseases in various regions around the world. He inspired a whole generation of future malaria researchers, making him an inescapable figure among Portuguese malariologists in the second half of the 20^th century.At the dawn of the 21^st century, many Portuguese scientists, who had benefitted from the country’s investment in science in the 1980s and 1990s to acquire international training, came back home to set up their own research groups. Among them was Maria Mota, who returned from New York University to Portugal in 2002 to become a group leader, initially at the Instituto Gulbenkian de Ciência (IGC), and subsequently at the Instituto de Medicina Molecular (iMM). Mota’s research on the liver stage of infection by Plasmodium parasites has had an enormous impact and yielded a plethora of outstanding publications. She became Director of iMM in 2014, and commonly features among the most influential women in Portugal. Mota is also a gifted and engaging communicator, who has helped to garner public attention to malaria research and to the fight against the disease. As a great scientist and public advocate for malaria research, Mota has inspired numerous scientists, several of whom have become independent malaria researchers themselves, both in Portugal and internationally.

As a great scientist and public advocate for malaria research, Mota has inspired numerous scientists, several of whom have become independent malaria researchers themselves…

These historical, epidemiological, and humane factors have made Portugal an important player in malaria research, from the basic science of the parasite to the pathology of the disease, and from epidemiology to clinical research and drug development. However, these great achievements, and the role played by individual inspiring scientists, should not be taken for granted, but rather serve as an argument for nurturing and supporting research on malaria by future generations of scientists and political decision‐makers. A small country with fairly limited financial and human resources cannot reasonably aspire to excel in every area of research, but it can efficiently direct and focus its investment on those that are more likely to generate success. The history of Portuguese malaria research clearly demonstrates this and warrants its continued support as a top priority for national science policies.Further ReadingImportant contributions to malaria research by Portuguese laboratories during the past decade Drug development, discovery and repurposing Oliveira R, Guedes RC, Meireles P, Albuquerque IS, Goncalves LM, Pires E, Bronze MR, Gut J, Rosenthal PJ, Prudencio M, Moreira R, O''Neill PM, Lopes F (2014) Tetraoxane‐pyrimidine nitrile hybrids as dual stage antimalarials. J Med Chem 57: 4916–4923da Cruz FP, Martin C, Buchholz K, Lafuente‐Monasterio MJ, Rodrigues T, Sonnichsen B, Moreira R, Gamo FJ, Marti M, Mota MM, Hannus M, Prudencio M (2012) Drug screen targeted at Plasmodium liver stages identifies a potent multistage antimalarial drug. J Infect Dis 205: 1278–1286Hanson KK, Ressurreicao AS, Buchholz K, Prudencio M, Herman‐Ornelas JD, Rebelo M, Beatty WL, Wirth DF, Hanscheid T, Moreira R, Marti M, Mota MM (2013) Torins are potent antimalarials that block replenishment of Plasmodium liver stage parasitophorous vacuole membrane proteins. Proc Natl Acad Sci USA 110: E2838–E2847Machado M, Sanches‐Vaz M, Cruz JP, Mendes AM, Prudencio M (2017) Inhibition of Plasmodium Hepatic Infection by Antiretroviral Compounds. Front Cell Infect Microbiol 7: 329 Genetic diversity of Plasmodium parasites Guerra M, Neres R, Salgueiro P, Mendes C, Ndong‐Mabale N, Berzosa P, de Sousa B, Arez AP (2017) Plasmodium falciparum Genetic Diversity in Continental Equatorial Guinea before and after Introduction of Artemisinin‐Based Combination Therapy. Antimicrob Agents Chemother 61Mendes C, Salgueiro P, Gonzalez V, Berzosa P, Benito A, do Rosario VE, de Sousa B, Cano J, Arez AP (2013) Genetic diversity and signatures of selection of drug resistance in Plasmodium populations from both human and mosquito hosts in continental Equatorial Guinea. Malar J 12: 114 Mechanisms of drug resistance Escobar C, Pateira S, Lobo E, Lobo L, Teodosio R, Dias F, Fernandes N, Arez AP, Varandas L, Nogueira F (2015) Polymorphisms in Plasmodium falciparum K13‐propeller in Angola and Mozambique after the introduction of the ACTs. PLoS One 10: e0119215Ferreira A, Marguti I, Bechmann I, Jeney V, Chora A, Palha NR, Rebelo S, Henri A, Beuzard Y, Soares MP (2011) Sickle hemoglobin confers tolerance to Plasmodium infection. Cell 145: 398–409Veiga MI, Osorio NS, Ferreira PE, Franzen O, Dahlstrom S, Lum JK, Nosten F, Gil JP (2014) Complex polymorphisms in the Plasmodium falciparum multidrug resistance protein 2 gene and its contribution to antimalarial response. Antimicrob Agents Chemother 58: 7390–7397 Host‐Plasmodium interactions Portugal S, Carret C, Recker M, Armitage AE, Goncalves LA, Epiphanio S, Sullivan D, Roy C, Newbold CI, Drakesmith H, Mota MM (2011) Host‐mediated regulation of superinfection in malaria. Nat Med 17: 732–737Real E, Rodrigues L, Cabal GG, Enguita FJ, Mancio‐Silva L, Mello‐Vieira J, Beatty W, Vera IM, Zuzarte‐Luis V, Figueira TN, Mair GR, Mota MM (2018) Plasmodium UIS3 sequesters host LC3 to avoid elimination by autophagy in hepatocytes. Nat Microbiol 3: 17–25Sa ECC, Nyboer B, Heiss K, Sanches‐Vaz M, Fontinha D, Wiedtke E, Grimm D, Przyborski JM, Mota MM, Prudencio M, Mueller AK (2017) Plasmodium berghei EXP‐1 interacts with host Apolipoprotein H during Plasmodium liver‐stage development. Proc Natl Acad Sci USA 114: E1138–E1147 Nutrient sensing and acquisition Itoe MA, Sampaio JL, Cabal GG, Real E, Zuzarte‐Luis V, March S, Bhatia SN, Frischknecht F, Thiele C, Shevchenko A, Mota MM (2014) Host cell phosphatidylcholine is a key mediator of malaria parasite survival during liver stage infection. Cell Host Microbe 16: 778–786Mancio‐Silva L, Slavic K, Grilo Ruivo MT, Grosso AR, Modrzynska KK, Vera IM, Sales‐Dias J, Gomes AR, MacPherson CR, Crozet P, Adamo M, Baena‐Gonzalez E, Tewari R, Llinas M, Billker O, Mota MM (2017) Nutrient sensing modulates malaria parasite virulence. Nature 547: 213–216Meireles P, Mendes AM, Aroeira RI, Mounce BC, Vignuzzi M, Staines HM, Prudencio M (2017) Uptake and metabolism of arginine impact Plasmodium development in the liver. Sci Rep 7: 4072 Modulation of Plasmodium liver infection Ruivo MTG, Vera IM, Sales‐Dias J, Meireles P, Gural N, Bhatia SN, Mota MM, Mancio‐Silva L (2016) Host AMPK Is a Modulator of Plasmodium Liver Infection. 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Birth cohort relative to an influenza A virus’s antigenic cluster introduction drives patterns of children’s antibody titers

An individual’s antibody titers to influenza A strains are a result of the complicated interplay between infection history, cross-reactivity, immune waning, and other factors. It has been challenging to disentangle how population-level patterns of humoral immunity change as a function of age, calendar year, and birth cohort from cross-sectional data alone. We analyzed 1,589 longitudinal sera samples from 260 children across three studies in Nicaragua, 2006–16. Hemagglutination inhibition (HAI) titers were determined against four H3N2 strains, one H1N1 strain, and two H1N1pdm strains. We assessed temporal patterns of HAI titers using an age–period–cohort modeling framework. We found that titers against a given virus depended on calendar year of serum collection and birth cohort but not on age. Titer cohort patterns were better described by participants’ ages relative to year of likely introduction of the virus’s antigenic cluster than by age relative to year of strain introduction or by year of birth. These cohort effects may be driven by a decreasing likelihood of early-life infection after cluster introduction and by more broadly reactive antibodies at a young age. H3N2 and H1N1 viruses had qualitatively distinct cohort patterns, with cohort patterns of titers to specific H3N2 strains reaching their peak in children born 3 years prior to that virus’s antigenic cluster introduction and with titers to H1N1 and H1N1pdm strains peaking for children born 1–2 years prior to cluster introduction but not being dramatically lower for older children. Ultimately, specific patterns of strain circulation and antigenic cluster introduction may drive population-level antibody titer patterns in children.