Plasmodium Falciparum-infected Erythrocytes Adhere to Class A Scavenger Receptor, SR-A

Severe falciparum malaria such as cerebral malaria and severe anemia is leading causes of morbidity and mortality. Plasmodium falciparum-infected red blood cells (pRBC) adhere to the endothelial cells via receptors expressed on the surface of the endothelial cells, and sequester in the microvasculature of several organs. Severe anemia, which may be due to a number of factors including rupture of the pRBC and phagocytosis of pRBC, is another cause of death. However, the molecular mechanism underlying both the cytoadherence and erythrophagocytosis related with severe malaria is not completely understood. Here, we report that the pRBC bind to the class A scavenger receptor, scavenger receptor A (SR-A), which is expressed on the surface of the activated phagocytes. 　First, we confirmed mRNA expression of scavenger receptors in the various tissues of P. berghei ANKA-infected mice. The expression of SR-A mRNA in all tissues was enhanced for 7 days postinfection. We also confirmed mRNA expression of SR-A in the human macrophage cell line, THP-1 cells, cultivated with pRBC. SR-A mRNA expression in THP-1 cells with pRBCs was observed after 24 hr cultivation, but not RBCs. Then, to identify cytoadherence of pRBCs to SR-A, human SR-A cDNA was transfected to CHO cells (CHO-SR-A cells). pRBC adhered to the CHO-SR-A cells, but not to the CHO-mock cells. Interestingly, the cytoadherence of both mature stage and ring form pRBCs to the CHO-SR-A cells was observed. Anti-SR-A antibody, but not Anexin V, efficiently blocked the cytoadherence of the pRBC to the CHO-SR-A cells. 　These results may suggest that SR-A acts as a host factor related with cytoadherence of the pRBC, which contributes to our present understanding of the pathology of severe falciparum malaria

Mulberry juice freeze-dried powder attenuates the disease severity by the maintaining of colon mucosa in mice with DSS-induced acute colitis

This study aimed to evaluate the microbial compositions and gene expression related to inflammation in dextran sodium sulfate (DSS)-induced acute colitis and the effect of mulberry supplementation. Male BALB/c mice received a diet supplemented with mulberry juice freeze-dried powder (MFP) or not for 3 weeks. After 3 weeks, the mice received water containing 5% (w/v) DSS or not for 1 week. The disease activity index score in mice fed MFP was significantly decreased. A significant decrease in Bifidobacterium spp. and the Clostridium perfringens subgroup was observed in mice not fed MFP. The number of goblet cell and NLRP6 expression were observed in mice fed a diet supplemented with MFP compared with mice not fed MFP. These results may indicate that mulberry mitigates DSS-induced acute colitis by a changing the gut microbial flora and by improving mucosal conditions

Avian coccidiosis : Toward the understanding of pathophysiology in Eimeria tenella infection

Avian coccidiosis is most important entero-parasitic disease in the world. Eimeria parasite is causative agent of this disease. In Japan, this parasite species were widely spread and the positive rates are about 50 in layer and 70 % in broiler. The symptoms of coccidiosis are diarrhea, bloody excretion, weight loss, and die. Eimeria tenella is the most pathogenic protozoa. The sporozoites, infection form of this parasite, entry to epithelial cells around the crypt of cecum in early infection. After infection, parasites proliferate in epithelial cells, and form to sexual stage finally. However, we have less information about the pathophysiology, especially invasive mechanisms and infection route, by E. tenella infection. We have focused to analyze the invasive mechanism and route of this parasite because this phenomenon is first event to cause the pathophysiological changes in the infection. I would like to inform about Eimeria parasite and introduce our research in this paper

Alteration of chemokine production in bovine endometrial epithelial and stromal cells under heat stress conditions

After parturition, cows frequently develop uterine bacterial infections, resulting in the onset of endometritis. To eliminate the bacteria, bovine endometrial cells secrete chemokines, such as IL-6 and MCP1, which attract macrophages (M Phi s) to the subepithelial stroma. These attracted M Phi s are not only involved in bacterial elimination but also the orchestration of inflammation and tissue repair. These immune responses aid in the recovery from endometritis; however, the recovery from endometritis takes longer in summer than in any other season. Based on these findings, we hypothesized that heat stress (HS) affects the chemokine production in endometrial cells. To confirm this hypothesis, we compared IL-6 and MCP1 production induced by lipopolysaccharide (LPS) in bovine endometrial epithelial and stromal cells under normal (38.5 degrees C) and HS conditions (40.5 degrees C). In the endometrial epithelial cells, IL-6 production stimulated by LPS was significantly (p < .05) suppressed under HS conditions. MCP1 production in endometrial epithelial cells was not detected under both the control and HS conditions regardless of the presence of LPS. Moreover, LPS significantly (p < .05) stimulated IL-6 and MCP1 production in endometrial stromal cells. Moreover, HS significantly (p < .05) enhanced their production compared to that under the control conditions. In addition, HS did not affect the migration ability of M Phi s; however, the supernatant of the endometrial stromal cells cultured under the HS condition significantly (p < .05) attracted the M Phi s when compared to the control condition. These results suggest that HS disrupts chemokine production in two types of endometrial cells and alters the distribution of M Phi s in the endometrium during the summer

Oral administration of the probiotic bacterium Lactobacillus acidophilus strain L-55 modulates the immunological parameters of the laying hen inoculated with a Newcastle disease virus-based live attenuated vaccine

Probiotic supplements containing living bacteria have attracted interest as a potential source of health benefits for humans and livestock. The aim of this study was to determine whether administration of Lactobacillus acidophilus strain L-55 (LaL-55) enhances the immune response among chicks exposed to a Newcastle disease virus (NDV)-based live attenuated vaccine. Oral administration of LaL-55 augmented the elevation in the total numbers of leukocytes and lymphocytes following inoculation with the NDV-based live attenuated vaccine. Monocyte counts increased after LaL-55 administration independent of inoculation with the NDV vaccine. Among chicks that were administered LaL-55, there was a dose-dependent increase in the NK cell activity measured by a 51Cr release assay at 2 weeks after the secondary NDV vaccine inoculation. Two weeks after the secondary inoculation with the NDV vaccine, interferon (IFN)-γ-mRNA expression was significantly elevated in mononuclear splenocytes from chicks that were administered LaL-55. Meanwhile, LaL-55 administration did not change the mRNA levels of IFN-α, IFN-β, and interleukin-1β. These results may suggest that coadministration of LaL-55 with an NDV vaccine augments the immune response against the virus. Therefore, LaL-55 may help protect against viral diseases in poultry

Relationship between Eimeria tenella associated-early clinical signs and molecular changes in the intestinal barrier function

The major clinical signs of coccidiosis in chickens due to Eimeria parasite are diarrhea and bloody feces. Previous studies showed that the impairment of the intestinal epithelial barrier and the elevation of the intestinal permeability are causes of clinical signs associated with coccidia challenges. Nevertheless, the information about molecular changes of the epithelial barrier at the early stage of the infection with a specific Eimeria species has not been mentioned. Hence, this study aims to elucidate the temporal relationships between epithelial barrier conditions and clinical signs in chickens infected with Eimeria tenella over the time from the earliest stages of infection. White Leghorn chickens were inoculated with 1 × 104 oocysts of E. tenella. Thereafter the chickens were monitored for their daily clinical signs through observation, and between 5 dpi to 10 dpi, feces were collected for oocysts counting. Chickens were then administrated with fluorescein isothiocyanate-dextran (FITC-d) for gastrointestinal permeability test and tissues were collected each day for histopathological observation and total RNA extraction. Finally, the mRNA expression levels of the tight and adherens junction genes and cytokine genes were evaluated using the quantitative real-time polymerase chain reaction (qRT-PCR). In this study, clinical signs such as diarrhea and bloody feces were observed concurrently from 3 to 8 dpi. Histopathology changes such as severe inflammation, hemorrhage, and epithelial desquamation were identified in the cecum specimens. The FITC-d level in the E. tenella-infected group was significantly higher than in the control group. In the infected group, the expression of claudin-2 gene was also upregulated, whereas the expressions of claudin-3 and E-cadherin genes were decreased as compared to the control group. These results implied that clinical signs of avian coccidiosis were associated with the intestinal barrier disruption via changes in expression levels of claudins and E-cadherin at the intestine

Reduction of macrophages by carrageenan decreases oocyst output and modifies local immune reaction in chick cecum with Eimeria tenella

This study aimed to evaluate the disease severity and local immune responses in macrophage-depleted chicks with Eimeria tenella. Macrophages were reduced by intraperitoneal injection of a carrageenan solution at 12, 13, and 16 days old, whereas the control group received intraperitoneal phosphate-buffered saline. Both chick groups were orally inoculated with E. tenella sporulated oocysts at 14 days old. Feces were collected daily, which were then quantified for oocysts. The chicks were sacrificed on day 5, and the ceca were collected for histopathological observation. The gene expression levels were measured using real-time quantitative reverse transcription-polymerase chain reaction. Macrophage-depleted chicks have been observed to shed a significantly reduced number of fecal oocysts compared to the infected control group. The parasite burden score in cecum specimens of macrophage-depleted chicks was significantly lower than those of infected control on day 5 after infection. Furthermore, macrophage reduction yielded significantly lower cecum histopathological scores and CD4 expression than those of the infected control group. The expression of interleukin (IL)-18, IL-22, interferon-γ, and inducible nitric oxide synthase was also noted to be significantly upregulated in both infected control and macrophage-depleted chicks compared to uninfected chicks. IL-4, IL-13, IL-17, and perforin expressions were also higher with macrophage depletion than in both control groups. These results suggest that macrophages serve as an invasive gate or a transporting vehicle to the site of first merogony. Furthermore, mononuclear phagocytes may play an important role in local immune responses, thus contributing to parasite development during early E. tenella infection

Genetic diversity and population structure of Plasmodium falciparum in the Philippines

<p>Abstract</p> <p>Background</p> <p>In the Philippines, malaria morbidity and mortality have decreased since the 1990s by effective malaria control. Several epidemiological surveys have been performed in the country, but the characteristics of the <it>Plasmodium falciparum </it>populations are not yet fully understood. In this study, the genetic structure of <it>P. falciparum </it>populations in the Philippines was examined.</p> <p>Methods</p> <p>Population genetic analyses based on polymorphisms of 10 microsatellite loci of the parasite were conducted on 92 isolates from three provinces (Kalinga, Palawan, and Davao del Norte) with different malaria endemicity.</p> <p>Results</p> <p>The levels of genetic diversity and the effective population sizes of <it>P. falciparum </it>in the Philippines were similar to those reported in the mainland of Southeast Asia or South America. In the low malaria transmission area (Kalinga), there was a low level of genetic diversity and a strong linkage disequilibrium (LD) when the single-clone haplotype (SCH) was used in the multilocus LD analysis, while in the high malaria transmission areas (Palawan and Davao del Norte), there was a high level of genetic diversity and a weak LD when SCH was used in the multilocus LD analysis. On the other hand, when the unique haplotypes were used in the multilocus LD analysis, no significant LD was observed in the Kalinga and the Palawan populations. The Kalinga and the Palawan populations were, therefore, estimated to have an epidemic population structure. The three populations were moderately differentiated from each other.</p> <p>Conclusion</p> <p>In each area, the level of genetic diversity correlates with the local malaria endemicity. These findings confirm that population genetic analyses using microsatellite loci are a useful tool for evaluating malaria endemicity.</p

Avian coccidiosis : Toward the understanding of pathophysiology in Eimeria tenella infection

Avian coccidiosis is most important entero-parasitic disease in the world. Eimeria parasite is causative agent of this disease. In Japan, this parasite species were widely spread and the positive rates are about 50 in layer and 70 % in broiler. The symptoms of coccidiosis are diarrhea, bloody excretion, weight loss, and die. Eimeria tenella is the most pathogenic protozoa. The sporozoites, infection form of this parasite, entry to epithelial cells around the crypt of cecum in early infection. After infection, parasites proliferate in epithelial cells, and form to sexual stage finally. However, we have less information about the pathophysiology, especially invasive mechanisms and infection route, by E. tenella infection. We have focused to analyze the invasive mechanism and route of this parasite because this phenomenon is first event to cause the pathophysiological changes in the infection. I would like to inform about Eimeria parasite and introduce our research in this paper