Publications by authors named "Dorothy E Loy"

18 Publications

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CD4 receptor diversity represents an ancient protection mechanism against primate lentiviruses.

Proc Natl Acad Sci U S A 2021 Mar;118(13)

Lukuru Wildlife Research Foundation, Tshuapa-Lomami-Lualaba Project, BP 2012, Kinshasa, Democratic Republic of the Congo.

Infection with human and simian immunodeficiency viruses (HIV/SIV) requires binding of the viral envelope glycoprotein (Env) to the host protein CD4 on the surface of immune cells. Although invariant in humans, the Env binding domain of the chimpanzee CD4 is highly polymorphic, with nine coding variants circulating in wild populations. Here, we show that within-species CD4 diversity is not unique to chimpanzees but found in many African primate species. Characterizing the outermost (D1) domain of the CD4 protein in over 500 monkeys and apes, we found polymorphic residues in 24 of 29 primate species, with as many as 11 different coding variants identified within a single species. D1 domain amino acid replacements affected SIV Env-mediated cell entry in a single-round infection assay, restricting infection in a strain- and allele-specific fashion. Several identical CD4 polymorphisms, including the addition of -linked glycosylation sites, were found in primate species from different genera, providing striking examples of parallel evolution. Moreover, seven different guenons ( spp.) shared multiple distinct D1 domain variants, pointing to long-term trans-specific polymorphism. These data indicate that the HIV/SIV Env binding region of the primate CD4 protein is highly variable, both within and between species, and suggest that this diversity has been maintained by balancing selection for millions of years, at least in part to confer protection against primate lentiviruses. Although long-term SIV-infected species have evolved specific mechanisms to avoid disease progression, primate lentiviruses are intrinsically pathogenic and have left their mark on the host genome.
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http://dx.doi.org/10.1073/pnas.2025914118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8020793PMC
March 2021

Ancient Introgression between Two Ape Malaria Parasite Species.

Genome Biol Evol 2019 11;11(11):3269-3274

Institute of Evolutionary Biology, and Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom.

The Laverania clade comprises the human malaria parasite Plasmodium falciparum as well as at least seven additional parasite species that infect wild African apes. A recent analysis of Laverania genome sequences (Otto TD, et al. 2018. Genomes of all known members of a Plasmodium subgenus reveal paths to virulent human malaria. Nat Microbiol. 3: 687-697) reported three instances of interspecies gene transfer, one of which had previously been described. Generating gene sequences from additional ape parasites and re-examining sequencing reads generated in the Otto et al. study, we identified one of the newly described gene transfers as an assembly artifact of sequences derived from a sample coinfected by two parasite species. The second gene transfer between ancestors of two divergent chimpanzee parasite lineages was confirmed, but involved a much larger number of genes than originally described, many of which encode exported proteins that remodel, or bind to, erythrocytes. Because successful hybridization between Laverania species is very rare, it will be important to determine to what extent these gene transfers have shaped their host interactions.
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http://dx.doi.org/10.1093/gbe/evz244DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7145702PMC
November 2019

Evolutionary history of human revealed by genome-wide analyses of related ape parasites.

Proc Natl Acad Sci U S A 2018 09 20;115(36):E8450-E8459. Epub 2018 Aug 20.

Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104;

Wild-living African apes are endemically infected with parasites that are closely related to human , a leading cause of malaria outside Africa. This finding suggests that the origin of was in Africa, even though the parasite is now rare in humans there. To elucidate the emergence of human and its relationship to the ape parasites, we analyzed genome sequence data of strains infecting six chimpanzees and one gorilla from Cameroon, Gabon, and Côte d'Ivoire. We found that ape and human parasites share nearly identical core genomes, differing by only 2% of coding sequences. However, compared with the ape parasites, human strains of exhibit about 10-fold less diversity and have a relative excess of nonsynonymous nucleotide polymorphisms, with site-frequency spectra suggesting they are subject to greatly relaxed purifying selection. These data suggest that human has undergone an extreme bottleneck, followed by rapid population expansion. Investigating potential host-specificity determinants, we found that ape parasites encode intact orthologs of three reticulocyte-binding protein genes (, , and ), which are pseudogenes in all human strains. However, binding studies of recombinant RBP2e and RBP3 proteins to human, chimpanzee, and gorilla erythrocytes revealed no evidence of host-specific barriers to red blood cell invasion. These data suggest that, from an ancient stock of parasites capable of infecting both humans and apes, a severely bottlenecked lineage emerged out of Africa and underwent rapid population growth as it spread globally.
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http://dx.doi.org/10.1073/pnas.1810053115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6130405PMC
September 2018

Investigating zoonotic infection barriers to ape Plasmodium parasites using faecal DNA analysis.

Int J Parasitol 2018 06 21;48(7):531-542. Epub 2018 Feb 21.

Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address:

African apes are endemically infected with numerous Plasmodium spp. including close relatives of human Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae. Although these ape parasites are not believed to pose a zoonotic threat, their ability to colonise humans has not been fully explored. In particular, it remains unknown whether ape parasites are able to initiate exo-erythrocytic replication in human hepatocytes following the bite of an infective mosquito. Since animal studies have shown that liver stage infection can result in the excretion of parasite nucleic acids into the bile, we screened faecal samples from 504 rural Cameroonians for Plasmodium DNA. Using pan-Laverania as well as P. malariae- and P. vivax-specific primer sets, we amplified human P. falciparum (n = 14), P. malariae (n = 1), and P. ovale wallikeri (n = 1) mitochondrial sequences from faecal DNA of 15 individuals. However, despite using an intensified PCR screening approach we failed to detect ape Laverania, ape P. vivax or ape P. malariae parasites in these same subjects. One faecal sample from a hunter-gatherer contained a sequence closely related to the porcupine parasite Plasmodium atheruri. Since this same faecal sample also contained porcupine mitochondrial DNA, but a matching blood sample was Plasmodium-negative, it is likely that this hunter-gatherer consumed Plasmodium-infected bushmeat. Faecal Plasmodium detection was not secondary to intestinal bleeding and/or infection with gastrointestinal parasites, but indicative of blood parasitaemia. Quantitative PCR identified 26-fold more parasite DNA in the blood of faecal Plasmodium-positive than faecal Plasmodium-negative individuals (P = 0.01). However, among blood-positive individuals only 10% - 20% had detectable Plasmodium sequences in their stool. Thus, faecal screening of rural Cameroonians failed to uncover abortive ape Plasmodium infections, but detected infection with human parasites, albeit with reduced sensitivity compared with blood analysis.
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http://dx.doi.org/10.1016/j.ijpara.2017.12.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5971147PMC
June 2018

Adaptive Evolution of RH5 in Ape species of the Subgenus.

mBio 2018 01 23;9(1). Epub 2018 Jan 23.

Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom

, the major cause of malaria morbidity and mortality in humans, has been shown to have emerged after cross-species transmission of one of six host-specific parasites (subgenus ) infecting wild chimpanzees () and western gorillas (). Binding of the parasite-encoded ligand RH5 to the host protein basigin is essential for erythrocyte invasion and has been implicated in host specificity. A recent study claimed to have found two amino acid changes in RH5 that "drove the host shift leading to the emergence of as a human pathogen." However, the ape data available at that time, which included only a single distantly related chimpanzee parasite sequence, were inadequate to justify any such conclusion. Here, we have investigated gene evolution using sequences from all six ape parasite species. Searching for gene-wide episodic selection across the entire phylogeny, we found eight codons to be under positive selection, including three that correspond to contact residues known to form hydrogen bonds between RH5 and human basigin. One of these sites (residue 197) has changed subsequent to the transmission from apes to humans that gave rise to , suggesting a possible role in the adaptation of the gorilla parasite to the human host. We also found evidence that the patterns of nucleotide polymorphisms in are not typical of species and likely reflect the recent demographic history of the human parasite. A number of closely related, host-specific malaria parasites infecting wild chimpanzees and gorillas have recently been described. The most important cause of human malaria, , is now known to have resulted from a cross-species transmission of one of the gorilla parasites. Overcoming species-specific interactions between a parasite ligand, RH5, and its receptor on host cells, basigin, was likely an important step in the origin of the human parasite. We have investigated the evolution of the gene and found evidence of adaptive changes during the diversification of the ape parasite species at sites that are known to form bonds with human basigin. One of these changes occurred at the origin of , implicating it as an important adaptation to the human host.
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http://dx.doi.org/10.1128/mBio.02237-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5784257PMC
January 2018

Wild bonobos host geographically restricted malaria parasites including a putative new Laverania species.

Nat Commun 2017 11 21;8(1):1635. Epub 2017 Nov 21.

Department of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.

Malaria parasites, though widespread among wild chimpanzees and gorillas, have not been detected in bonobos. Here, we show that wild-living bonobos are endemically Plasmodium infected in the eastern-most part of their range. Testing 1556 faecal samples from 11 field sites, we identify high prevalence Laverania infections in the Tshuapa-Lomami-Lualaba (TL2) area, but not at other locations across the Congo. TL2 bonobos harbour P. gaboni, formerly only found in chimpanzees, as well as a potential new species, Plasmodium lomamiensis sp. nov. Rare co-infections with non-Laverania parasites were also observed. Phylogenetic relationships among Laverania species are consistent with co-divergence with their gorilla, chimpanzee and bonobo hosts, suggesting a timescale for their evolution. The absence of Plasmodium from most field sites could not be explained by parasite seasonality, nor by bonobo population structure, diet or gut microbiota. Thus, the geographic restriction of bonobo Plasmodium reflects still unidentified factors that likely influence parasite transmission.
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http://dx.doi.org/10.1038/s41467-017-01798-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5696340PMC
November 2017

Selective Whole-Genome Amplification Is a Robust Method That Enables Scalable Whole-Genome Sequencing of Plasmodium vivax from Unprocessed Clinical Samples.

mBio 2017 02 7;8(1). Epub 2017 Feb 7.

Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego, La Jolla, California, USA

Whole-genome sequencing (WGS) of microbial pathogens from clinical samples is a highly sensitive tool used to gain a deeper understanding of the biology, epidemiology, and drug resistance mechanisms of many infections. However, WGS of organisms which exhibit low densities in their hosts is challenging due to high levels of host genomic DNA (gDNA), which leads to very low coverage of the microbial genome. WGS of Plasmodium vivax, the most widely distributed form of malaria, is especially difficult because of low parasite densities and the lack of an ex vivo culture system. Current techniques used to enrich P. vivax DNA from clinical samples require significant resources or are not consistently effective. Here, we demonstrate that selective whole-genome amplification (SWGA) can enrich P. vivax gDNA from unprocessed human blood samples and dried blood spots for high-quality WGS, allowing genetic characterization of isolates that would otherwise have been prohibitively expensive or impossible to sequence. We achieved an average genome coverage of 24×, with up to 95% of the P. vivax core genome covered by ≥5 reads. The single-nucleotide polymorphism (SNP) characteristics and drug resistance mutations seen were consistent with those of other P. vivax sequences from a similar region in Peru, demonstrating that SWGA produces high-quality sequences for downstream analysis. SWGA is a robust tool that will enable efficient, cost-effective WGS of P. vivax isolates from clinical samples that can be applied to other neglected microbial pathogens.

Importance: Malaria is a disease caused by Plasmodium parasites that caused 214 million symptomatic cases and 438,000 deaths in 2015. Plasmodium vivax is the most widely distributed species, causing the majority of malaria infections outside sub-Saharan Africa. Whole-genome sequencing (WGS) of Plasmodium parasites from clinical samples has revealed important insights into the epidemiology and mechanisms of drug resistance of malaria. However, WGS of P. vivax is challenging due to low parasite levels in humans and the lack of a routine system to culture the parasites. Selective whole-genome amplification (SWGA) preferentially amplifies the genomes of pathogens from mixtures of target and host gDNA. Here, we demonstrate that SWGA is a simple, robust method that can be used to enrich P. vivax genomic DNA (gDNA) from unprocessed human blood samples and dried blood spots for cost-effective, high-quality WGS.
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http://dx.doi.org/10.1128/mBio.02257-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5296604PMC
February 2017

Out of Africa: origins and evolution of the human malaria parasites Plasmodium falciparum and Plasmodium vivax.

Int J Parasitol 2017 02 2;47(2-3):87-97. Epub 2016 Jul 2.

Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address:

Plasmodium falciparum and Plasmodium vivax account for more than 95% of all human malaria infections, and thus pose a serious public health challenge. To control and potentially eliminate these pathogens, it is important to understand their origins and evolutionary history. Until recently, it was widely believed that P. falciparum had co-evolved with humans (and our ancestors) over millions of years, whilst P. vivax was assumed to have emerged in southeastern Asia following the cross-species transmission of a parasite from a macaque. However, the discovery of a multitude of Plasmodium spp. in chimpanzees and gorillas has refuted these theories and instead revealed that both P. falciparum and P. vivax evolved from parasites infecting wild-living African apes. It is now clear that P. falciparum resulted from a recent cross-species transmission of a parasite from a gorilla, whilst P. vivax emerged from an ancestral stock of parasites that infected chimpanzees, gorillas and humans in Africa, until the spread of the protective Duffy-negative mutation eliminated P. vivax from human populations there. Although many questions remain concerning the biology and zoonotic potential of the P. falciparum- and P. vivax-like parasites infecting apes, comparative genomics, coupled with functional parasite and vector studies, are likely to yield new insights into ape Plasmodium transmission and pathogenesis that are relevant to the treatment and prevention of human malaria.
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http://dx.doi.org/10.1016/j.ijpara.2016.05.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5205579PMC
February 2017

Multigenomic Delineation of Plasmodium Species of the Laverania Subgenus Infecting Wild-Living Chimpanzees and Gorillas.

Genome Biol Evol 2016 07 2;8(6):1929-39. Epub 2016 Jul 2.

Institute of Evolutionary Biology, and Centre for Immunity, Infection and Evolution, University of Edinburgh, United Kingdom

Plasmodium falciparum, the major cause of malaria morbidity and mortality worldwide, is only distantly related to other human malaria parasites and has thus been placed in a separate subgenus, termed Laverania Parasites morphologically similar to P. falciparum have been identified in African apes, but only one other Laverania species, Plasmodium reichenowi from chimpanzees, has been formally described. Although recent studies have pointed to the existence of additional Laverania species, their precise number and host associations remain uncertain, primarily because of limited sampling and a paucity of parasite sequences other than from mitochondrial DNA. To address this, we used limiting dilution polymerase chain reaction to amplify additional parasite sequences from a large number of chimpanzee and gorilla blood and fecal samples collected at two sanctuaries and 30 field sites across equatorial Africa. Phylogenetic analyses of more than 2,000 new sequences derived from the mitochondrial, nuclear, and apicoplast genomes revealed six divergent and well-supported clades within the Laverania parasite group. Although two of these clades exhibited deep subdivisions in phylogenies estimated from organelle gene sequences, these sublineages were geographically defined and not present in trees from four unlinked nuclear loci. This greatly expanded sequence data set thus confirms six, and not seven or more, ape Laverania species, of which P. reichenowi, Plasmodium gaboni, and Plasmodium billcollinsi only infect chimpanzees, whereas Plasmodium praefalciparum, Plasmodium adleri, and Pladmodium blacklocki only infect gorillas. The new sequence data also confirm the P. praefalciparum origin of human P. falciparum.
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http://dx.doi.org/10.1093/gbe/evw128DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4943199PMC
July 2016

Genomes of cryptic chimpanzee Plasmodium species reveal key evolutionary events leading to human malaria.

Nat Commun 2016 Mar 22;7:11078. Epub 2016 Mar 22.

Department of Medicine, University of Pennsylvania, Philadelphia, 19104 Pennsylvania, USA.

African apes harbour at least six Plasmodium species of the subgenus Laverania, one of which gave rise to human Plasmodium falciparum. Here we use a selective amplification strategy to sequence the genome of chimpanzee parasites classified as Plasmodium reichenowi and Plasmodium gaboni based on the subgenomic fragments. Genome-wide analyses show that these parasites indeed represent distinct species, with no evidence of cross-species mating. Both P. reichenowi and P. gaboni are 10-fold more diverse than P. falciparum, indicating a very recent origin of the human parasite. We also find a remarkable Laverania-specific expansion of a multigene family involved in erythrocyte remodelling, and show that a short region on chromosome 4, which encodes two essential invasion genes, was horizontally transferred into a recent P. falciparum ancestor. Our results validate the selective amplification strategy for characterizing cryptic pathogen species, and reveal evolutionary events that likely predisposed the precursor of P. falciparum to colonize humans.
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http://dx.doi.org/10.1038/ncomms11078DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4804174PMC
March 2016

Eave Screening and Push-Pull Tactics to Reduce House Entry by Vectors of Malaria.

Am J Trop Med Hyg 2016 Apr 1;94(4):868-78. Epub 2016 Feb 1.

Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands; International Centre of Insect Physiology and Ecology, Nairobi, Kenya; Chemical Process Engineering and Forest Products Research Centre, Department of Chemical Engineering, University of Coimbra, Coimbra, Portugal; Devan-Micropolis, Tecmaia-Parque da Ciência e Tecnologia da Maia, Maia, Portugal; Devan Chemicals NV, Ronse, Belgium; Utexbel NV, Ronse, Belgium; Departments of Medicine and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; School of Biological Sciences, University of Nairobi, Nairobi, Kenya

Long-lasting insecticidal nets and indoor residual spraying have contributed to a decline in malaria over the last decade, but progress is threatened by the development of physiological and behavioral resistance of mosquitoes against insecticides. Acknowledging the need for alternative vector control tools, we quantified the effects of eave screening in combination with a push-pull system based on the simultaneous use of a repellent (push) and attractant-baited traps (pull). Field experiments in western Kenya showed that eave screening, whether used in combination with an attractant-baited trap or not, was highly effective in reducing house entry by malaria mosquitoes. The magnitude of the effect varied for different mosquito species and between two experiments, but the reduction in house entry was always considerable (between 61% and 99%). The use of outdoor, attractant-baited traps alone did not have a significant impact on mosquito house entry but the high number of mosquitoes trapped outdoors indicates that attractant-baited traps could be used for removal trapping, which would enhance outdoor as well as indoor protection against mosquito bites. As eave screening was effective by itself, addition of a repellent was of limited value. Nevertheless, repellents may play a role in reducing outdoor malaria transmission in the peridomestic area.
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http://dx.doi.org/10.4269/ajtmh.15-0632DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4824231PMC
April 2016

Ape parasite origins of human malaria virulence genes.

Nat Commun 2015 Oct 12;6:8368. Epub 2015 Oct 12.

Center for Communicable Disease Dynamics, Harvard School of Public Health, Boston, Massachusetts 02115, USA.

Antigens encoded by the var gene family are major virulence factors of the human malaria parasite Plasmodium falciparum, exhibiting enormous intra- and interstrain diversity. Here we use network analysis to show that var architecture and mosaicism are conserved at multiple levels across the Laverania subgenus, based on var-like sequences from eight single-species and three multi-species Plasmodium infections of wild-living or sanctuary African apes. Using select whole-genome amplification, we also find evidence of multi-domain var structure and synteny in Plasmodium gaboni, one of the ape Laverania species most distantly related to P. falciparum, as well as a new class of Duffy-binding-like domains. These findings indicate that the modular genetic architecture and sequence diversity underlying var-mediated host-parasite interactions evolved before the radiation of the Laverania subgenus, long before the emergence of P. falciparum.
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http://dx.doi.org/10.1038/ncomms9368DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4633637PMC
October 2015

Mosquito host preferences affect their response to synthetic and natural odour blends.

Malar J 2015 Mar 28;14:133. Epub 2015 Mar 28.

Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH, Wageningen, The Netherlands.

Background: The anthropophilic malaria mosquito Anopheles gambiae sensu stricto (hereafter termed Anopheles gambiae) primarily takes blood meals from humans, whereas its close sibling Anopheles arabiensis is more opportunistic. Previous studies have identified several compounds that play a critical role in the odour-mediated behaviour of An. gambiae. This study determined the effect of natural and synthetic odour blends on mosquitoes with different host preferences to better understand the host-seeking behaviour of mosquitoes and the potential of synthetic odour blends for standardized monitoring.

Methods: Odour blends were initially tested for their attractiveness to An. gambiae and An. arabiensis in a semi-field system with MM-X traps baited with natural and synthetic odours. Natural host odours were collected from humans, cows and chickens. The synthetic odour blends consisted of three or five previously identified compounds released with carbon dioxide. These studies were continued under natural conditions where odour blends were tested outdoors to determine their effect on species with different host preferences.

Results: In the semi-field experiments, human odour attracted significantly higher numbers of both mosquito species. However, An. arabiensis was also attracted to cow and chicken odours, which confirms its opportunistic behaviour. A five-component synthetic blend was highly attractive to both mosquito species. In the field, the synthetic odour blend caught significantly more An. funestus than traps baited with human odour, while no difference was found for An. arabiensis. Catches of An. arabiensis and Culex spp. contained large numbers of blood-fed mosquitoes, mostly from cows, which indicates that these mosquitoes had fed outdoors.

Conclusions: Different odour baits elicit varying responses among mosquito species. Synthetic odour blends are highly effective for trapping mosquitoes; however, not all mosquitoes respond equally to the same odour blend. Combining fermenting molasses with synthetic blends in a trap represents the most effective tool to catch blood-fed mosquitoes outside houses, which is essential for understanding outdoor malaria transmission.
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http://dx.doi.org/10.1186/s12936-015-0635-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4381365PMC
March 2015

The malagarasi river does not form an absolute barrier to chimpanzee movement in Western Tanzania.

PLoS One 2013 11;8(3):e58965. Epub 2013 Mar 11.

Department of Anthropology, University of California San Diego, San Diego, California, United States of America.

The Malagarasi River has long been thought to be a barrier to chimpanzee movements in western Tanzania. This potential geographic boundary could affect chimpanzee ranging behavior, population connectivity and pathogen transmission, and thus has implications for conservation strategies and government policy. Indeed, based on mitochondrial DNA sequence comparisons it was recently argued that chimpanzees from communities to the north and to the south of the Malagarasi are surprisingly distantly related, suggesting that the river prevents gene flow. To investigate this, we conducted a survey along the Malagarasi River. We found a ford comprised of rocks that researchers could cross on foot. On a trail leading to this ford, we collected 13 fresh fecal samples containing chimpanzee DNA, two of which tested positive for SIVcpz. We also found chimpanzee feces within the riverbed. Taken together, this evidence suggests that the Malagarasi River is not an absolute barrier to chimpanzee movements and communities from the areas to the north and south should be considered a single population. These results have important consequences for our understanding of gene flow, disease dynamics and conservation management.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0058965PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3594223PMC
December 2013

Prostaglandin D2 inhibits wound-induced hair follicle neogenesis through the receptor, Gpr44.

J Invest Dermatol 2013 Apr 29;133(4):881-9. Epub 2012 Nov 29.

Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Prostaglandins (PGs) are key inflammatory mediators involved in wound healing and regulating hair growth; however, their role in skin regeneration after injury is unknown. Using wound-induced hair follicle neogenesis (WIHN) as a marker of skin regeneration, we hypothesized that PGD2 decreases follicle neogenesis. PGE2 and PGD2 were elevated early and late, respectively, during wound healing. The levels of WIHN, lipocalin-type prostaglandin D2 synthase (Ptgds), and its product PGD2 each varied significantly among background strains of mice after wounding, and all correlated such that the highest Ptgds and PGD2 levels were associated with the lowest amount of regeneration. In addition, an alternatively spliced transcript variant of Ptgds missing exon 3 correlated with high regeneration in mice. Exogenous application of PGD2 decreased WIHN in wild-type mice, and PGD2 receptor Gpr44-null mice showed increased WIHN compared with strain-matched control mice. Furthermore, Gpr44-null mice were resistant to PGD2-induced inhibition of follicle neogenesis. In all, these findings demonstrate that PGD2 inhibits hair follicle regeneration through the Gpr44 receptor and imply that inhibition of PGD2 production or Gpr44 signaling will promote skin regeneration.
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http://dx.doi.org/10.1038/jid.2012.398DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3593761PMC
April 2013

Prostaglandin D2 inhibits hair growth and is elevated in bald scalp of men with androgenetic alopecia.

Sci Transl Med 2012 Mar;4(126):126ra34

Department of Dermatology, Kligman Laboratories, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.

Testosterone is necessary for the development of male pattern baldness, known as androgenetic alopecia (AGA); yet, the mechanisms for decreased hair growth in this disorder are unclear. We show that prostaglandin D(2) synthase (PTGDS) is elevated at the mRNA and protein levels in bald scalp compared to haired scalp of men with AGA. The product of PTGDS enzyme activity, prostaglandin D(2) (PGD(2)), is similarly elevated in bald scalp. During normal follicle cycling in mice, Ptgds and PGD(2) levels increase immediately preceding the regression phase, suggesting an inhibitory effect on hair growth. We show that PGD(2) inhibits hair growth in explanted human hair follicles and when applied topically to mice. Hair growth inhibition requires the PGD(2) receptor G protein (heterotrimeric guanine nucleotide)-coupled receptor 44 (GPR44), but not the PGD(2) receptor 1 (PTGDR). Furthermore, we find that a transgenic mouse, K14-Ptgs2, which targets prostaglandin-endoperoxide synthase 2 expression to the skin, demonstrates elevated levels of PGD(2) in the skin and develops alopecia, follicular miniaturization, and sebaceous gland hyperplasia, which are all hallmarks of human AGA. These results define PGD(2) as an inhibitor of hair growth in AGA and suggest the PGD(2)-GPR44 pathway as a potential target for treatment.
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http://dx.doi.org/10.1126/scitranslmed.3003122DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3319975PMC
March 2012