EphB2 Receptor Promotes Dermal Fibrosis in Systemic Sclerosis.

OBJECTIVE: Erythropoietin-producing hepatocellular (Eph)/Ephrin cell-cell signaling is emerging as a key player in tissue fibrogenesis. The aim of this study was to test the hypothesis that the receptor tyrosine kinase EphB2 mediates dermal fibrosis in systemic sclerosis (SSc). METHODS: We assessed normal and SSc human skin biopsies for EphB2 expression. The in vivo role of EphB2 in skin fibrosis was investigated by subjecting EphB2-knockout mice to both bleomycin-induced and tight skin (Tsk1/+) genetic mouse models of skin fibrosis. EphB2 kinase-dead and overactive point mutant mice were used to evaluate the role of EphB2 forward signaling in bleomycin-induced dermal fibrosis. In vitro studies were performed on dermal fibroblasts from patients with SSc and healthy controls, which was followed by in vivo analysis of fibroblast-specific Ephb2-deficient mice. RESULTS: Expression of EphB2 is up-regulated in SSc skin tissue and explanted SSc dermal fibroblasts compared with healthy controls. EphB2 expression is elevated in two animal models of dermal fibrosis. In mice, EphB2 drives dermal fibrosis in both the bleomycin and the Tsk1/+ models of skin fibrosis. EphB2 forward signaling is a critical mediator of dermal fibrosis. Transforming growth factor-ß (TGF-ß) cytokines up-regulate EphB2 in dermal fibroblasts via noncanonical TGF-ß/mother against decapentaplegic signaling, and silencing EPHB2 in human dermal fibroblasts is sufficient to dampen TGF-ß-induced fibroblast-to-myofibroblast differentiation. Moreover, mice with fibroblast-specific deletion of EphB2 showed impaired fibroblast-to-myofibroblast differentiation and reduced skin fibrosis upon bleomycin challenge. CONCLUSION: Our data implicate TGF-ß regulation of EphB2 overexpression and kinase-mediated forward signaling in the development of dermal fibrosis in SSc. EphB2 thus represents a potential new therapeutic target for SSc.

Harnessing Schistosoma-associated metabolite changes in the human host to identify biomarkers of infection and morbidity: Where are we and what should we do next?

Schistosomiasis is the second most widespread parasitic disease affecting humans. A key component of today's infection control measures is the diagnosis and monitoring of infection, informing individual- and community-level treatment. However, newly acquired infections and/or low parasite burden are still difficult to diagnose reliably. Furthermore, even though the pathological consequence of schistosome egg sequestration in host tissues is well described, the evidence linking egg burden to morbidity is increasingly challenged, making it inadequate for pathology monitoring. In the last decades, omics-based instruments and methods have been developed, adjusted, and applied in parasitic research. In particular, the profiling of the most reliable determinants of phenotypes, metabolites by metabolomics, emerged as a powerful boost in the understanding of basic interactions within the human host during infection. As such, the fine detection of host metabolites produced upon exposure to parasites such as Schistosoma spp. and the ensuing progression of the disease are believed to enable the identification of Schistosoma spp. potential biomarkers of infection and associated pathology. However, attempts to provide such a comprehensive understanding of the alterations of the human metabolome during schistosomiasis are rare, limited in their design when performed, and mostly inconclusive. In this review, we aimed to briefly summarize the most robust advances in knowledge on the changes in host metabolic profile during Schistosoma infections and provide recommendations for approaches to optimize the identification of metabolomic signatures of human schistosomiasis.

HAF Prevents Hepatocyte Apoptosis and Hepatocellular Carcinoma through Transcriptional Regulation of the NF-κB pathway.

Background: Hepatocellular carcinoma (HCC) incidence is increasing worldwide due to the obesity epidemic, which drives metabolic dysfunction-associated steatohepatitis (MASH) that can lead to HCC. However, the molecular pathways that lead to MASH-HCC are poorly understood. We have previously reported that male mice with global haploinsufficiency of hypoxia-associated factor, HAF ( SART1 +/ - ) spontaneously develop MASH/HCC. However, the cell type(s) responsible for HCC associated with HAF loss are unclear. Results: SART1 -floxed mice were crossed with mice expressing Cre-recombinase within hepatocytes (Alb-Cre; hepS -/- ) or macrophages (LysM-Cre, macS -/- ). Only hepS -/- mice (both male and female) developed HCC suggesting that HAF protects against HCC primarily within hepatocytes. HAF-deficient macrophages showed decreased P-p65 and P-p50 and in many major components of the NF-κB pathway, which was recapitulated using HAF siRNA in vitro . HAF depletion increased apoptosis both in vitro and in vivo , suggesting that HAF mediates a tumor suppressor role by suppressing hepatocyte apoptosis. We show that HAF regulates NF-κB activity by controlling transcription of TRADD and RIPK1 . Mice fed a high-fat diet (HFD) showed marked suppression of HAF, P-p65 and TRADD within their livers after 26 weeks, but manifest profound upregulation of HAF, P-65 and TRADD within their livers after 40 weeks of HFD, implicating deregulation of the HAF-NF-κB axis in the progression to MASH. In humans, HAF was significantly decreased in livers with simple steatosis but significantly increased in HCC compared to normal liver. Conclusions: HAF is novel transcriptional regulator of the NF-κB pathway that protects against hepatocyte apoptosis and is a key determinant of cell fate during progression to MASH and MASH-HCC.

Plasma IL-33 levels and immune activation in HIV-TB coinfection: a cross-sectional study in Yaoundé, Cameroon.

Introduction: HIV-1 and Mtb are characterized by immune activation and unbalances production of cytokines, but the expression of IL33 in HIV/TB coinfection remain understudied. This study aimed to evaluate the level of IL-33 in plasma of HIV and M. tuberculosis (HIV/TB) coinfected patients compared to patients with respective mono infections in Yaoundé. Methods: a cross-sectional study was conducted among patients attending the pneumology service and HIV treatment center of the Yaoundé Jamot Hospital. Plasma samples of 157 HIV/TB coinfected patients (n =26, 50% males and 50% females, mean age 39), HIV-1 monoinfected patients (n = 41, 41% males and 59% females, mean age 35), TB monoinfected patients (n = 48, 56% males and 44% females, mean age 37) and healthy controls (n = 42, 29% males and 71% females, mean age 32) were examined by enzyme-linked immunoassay (ELISA) to detect the levels of IL-33 cytokine. Results: plasma level of IL-33 were higher in HIV/TB coinfected (33.1±30.9 pg/ml) and TB monoinfected individuals (15.1±2.9 pg/ml) compared to healthy controls (14.0±3.4 pg/ml) and could not be detected in most of the HIV-1 monoinfected individuals (12.6±8.7 pg/ml). Interestingly, the increased plasma level of IL-33 in HIV/TB coinfected patients showed a statistically significant difference between healthy controls (33.1±30.9 pg/ml vs 14.0±3.4 pg/ml, P<0.0001) and HIV-1 monoinfected patients (33.1±30.9 pg/ml vs 12.6±8.7 pg/ml, P=0.0002). We further found that IL-33 was higher in patients with high viral load group (40.6±59.7 pg/ml vs 12.6±1.8 pg/ml), P= 0.47) whereas patients under highly active antiretroviral therapy (HAART) showed decreased level of IL-33 concentration as the number of years under ART increased. Our data showed a positive association between plasma IL-33 and viral load in the context of HIV/TB coinfection in our study population with a positive Pearson coefficient of r=0.21. Conclusion: this study indicates that plasma level of IL-33 differs among HIV/TB coinfected patients and respective monoinfections patients. The increased level of plasma IL-33 reveals that IL-33 measurement in HIV-1 monoinfected patients may represent an early predictor of development of tuberculosis.

Noninvasive Approach of Plasmodium falciparum Molecular Detection for Malaria Surveillance in Malaria Endemic Areas in Cameroon.

Background: Accurate, cost-effective, and noninvasive alternative molecular methods are needed for detecting low malaria parasitemia. The currently-used nested polymerase chain reaction (nPCR) requires blood as well as skilled personnel in order to minimise the risk of bloodborne disease transmission. Therefore, this study is aimed at assessing the accuracy of a noninvasive and more affordable malaria diagnosis with saliva using the loop-mediated isothermal amplification (LAMP) technique. Methods: A cross-sectional study was conducted in the Centre and Southwest regions of Cameroon. Matched blood and saliva samples collected from symptomatic and asymptomatic participants were tested for malaria using rapid diagnostic tests, microscopy, PCR, and LAMP. Statistics were performed using R studio software at 95% confidence interval. Results: A total of 100 participants (65% symptomatic and 35% asymptomatic) aged between 1 and 74 years with a balanced gender distribution ratio of 1.08 were included in our study. The prevalence of malaria was 61%, 57%, 59%, 42%, 35%, 17%, and 16% for blood-RDT, blood-PCR, blood-LAMP, blood-RT-LAMP, saliva-PCR, saliva-RT-LAMP, and saliva-LAMP, respectively. Both saliva and blood showed a sensitivity of 43.90% and respective specificities of 68.75% and 57.62%. When using RT-LAMP, sensitivities of 49.38% and 48.21% and specificities of 94.11% and 66.67% were recorded for saliva and blood, respectively. Sensitivities of 70.23% and 73.49% and specificities of 62.5% and 76.47% were recorded, respectively, for saliva-LAMP and saliva-RT-LAMP when compared to saliva-PCR as the gold standard. Saliva-LAMP and saliva-RT-LAMP had a fair agreement (к = 0.221 and 0.352, respectively) with saliva-PCR. Homemade LAMP and RT-LAMP technologies match the WHO recommendations and after proper validation in a larger sample size, could serve for malaria diagnosis in developing countries.

Schistosoma mansoni infection induces plasmablast and plasma cell death in the bone marrow and accelerates the decline of host vaccine responses.

Schistosomiasis is a potentially lethal parasitic disease that profoundly impacts systemic immune function in chronically infected hosts through mechanisms that remain unknown. Given the immunoregulatory dysregulation experienced in infected individuals, this study examined the impact of chronic schistosomiasis on the sustainability of vaccine-induced immunity in both children living in endemic areas and experimental infections in mice. Data show that chronic Schistosoma mansoni infection impaired the persistence of vaccine specific antibody responses in poliovirus-vaccinated humans and mice. Mechanistically, schistosomiasis primarily fostered plasmablast and plasma cell death in the bone marrow and removal of parasites following praziquantel treatment reversed the observed cell death and partially restored vaccine-induced memory responses associated with increased serum anti-polio antibody responses. Our findings strongly suggest a previously unrecognized mechanism to explain how chronic schistosomiasis interferes with an otherwise effective vaccine regimen and further advocates for therapeutic intervention strategies that reduce schistosomiasis burden in endemic areas prior to vaccination.

Influence of schistosomiasis on host vaccine responses.

Schistosomiasis is a debilitating helminthiasis which commonly establishes as a chronic infection in people from endemic areas. As a potent modulator of the host immune response, the Schistosoma parasite and its associated products can directly interfere with its host's ability to mount adequate immune responses to unrelated antigens. As a result, increased attention is gathering on studies assessing the influence of helminths, particularly the causal agent of schistosomiasis, on host responsiveness to vaccines. However, to date, no consensus has been drawn regarding the influence of schistosomiasis on host vaccine responses. Here, we review available evidence on the influence of transgenerational and direct Schistosoma parasite exposure on host immune responses to unrelated vaccines. In addition, we evaluate the potential of praziquantel (PZQ) treatment in restoring schistosomiasis-impacted vaccine responses.

Investigating the antifibrotic effect of the antiparasitic drug Praziquantel in in vitro and in vivo preclinical models.

Tissue fibrosis underlies the majority of human mortality to date with close to half of all reported deaths having a fibrotic etiology. The progression of fibrosis is very complex and reputed irreversible once established. Although some preventive options are being reported, therapeutic options are still scarce and in very high demand, given the rise of diseases linked to fibroproliferative disorders. Our work explored four platforms, complementarily, in order to screen preventive and therapeutic potentials of the antiparasitic drug Praziquantel as a possible antifibrotic. We applied the mouse CCl4-driven liver fibrosis model, the mouse chronic schistosomiasis liver fibrosis model, as well as novel 2D and 3D human cell-based co-culture of human hepatocytes, KCs (Kupffer cells), LECs (Liver Endothelial Cells), HSCs (Hepatic Stellate Cells) and/or myofibroblasts to mimic in vivo fibrotic responses and dynamics. Praziquantel showed some effect on fibrosis marker when preventively administered before severe establishment of fibrosis. However, it failed to potently reverse already established fibrosis. Together, we provided a novel sophisticated multi-assay screening platform to test preventive and therapeutic antifibrotic candidates. We further demonstrated a direct preventive potential of Praziquantel against the onset of fibrosis and the confirmation of its lack of therapeutic potential in reversing already established fibrosis.

[Frequency and titration of hemolytic activity of anti-A and anti-B antibodies in mothers of children with jaundice in Yaoundé, Cameroon]. / Fréquence et titrage des hémolysines anti-A et anti-B chez les mères d'enfants ictériques à Yaoundé, Cameroun.

INTRODUCTION: The alloimmunization of the ABO blood group system is involved in neonatal jaundice with a considerable overall prevalence. The role of ABO incompatibility is relatively little known. The purpose of this study was to investigate neonatal jaundice due to feto-maternal ABO incompatibilities and to determine the link between the hemolysins value in the mother and the degree of jaundice observed in the infant. METHODS: We conducted a cross-sectional study from June to November 2015. The study population was exclusively composed of moms who were blood type O with children who were a different blood type hospitalized in the Department of Neonatology at the Reference Hospital in the city of Yaoundé. Statistical analyses were performed using the GraphPadPrism 6 software with a confidence interval of 95%. RESULTS: Hemolysins frequency was of 20.58% (7/34) and anti-A hemolysin was the most common type (85.7%; 6/7). The new-born who had blood type B had a greater concentration of bilirubin levels compared to those of the AB group (p = 0.01). Multiparity was not associated with the presence of hemolysin (p = 0.8) as well as blood type of the infant was not associated with the occurrence of the hemolysins in the mother (p = 0.5). CONCLUSION: Early neonatal jaundice or protracted neonatal jaundice are also caused by hemolysins anti-A and anti-B derived from the allo-ABO immunization. A study on a larger sample is recommended for better assessment.

An ultrasound-based referential of body height-adjusted normal liver organometry in school children from Bokito in rural Cameroon.

The grading system for ultrasonographic assessment of Schistosoma mansoni morbidity is crucial for evaluation of control programs. This requires prior definition of normal liver organometric ranges in the population from the endemic area. A cross-sectional study was conducted in a S. mansoni endemic area in rural Cameroon. 1002 Participants were screened and 234 of them, free from all common liver-affecting diseases in the area (schistosomiasis, malaria, hepatitis B and C) and with no ultrasonographic signs of liver disease were selected and their liver parameters measured by ultrasonography. All statistics were considered significant for p-values < 0.05. Normal dimensions of livers lobe sizes, portal vein wall thickness and portal vein diameters are reported. The liver organometric data are presented for the entire study population as a whole and separately for males and females as prediction plots, with observed values and fitted regression line with 95% confidence. Reference ranges for liver parameters (size, portal vein thickness and diameter) adjusted for body height established in the current study are novel for Cameroon. The prediction plots generated should improve the accuracy of the assessment of liver morbidity by ultrasonography in the region.

Negative Association of Interleukin-33 Plasma Levels and Schistosomiasis Infection in a Site of Polyparasitism in Rural Cameroon.

Background: This study aimed to investigate the association of plasma levels of IL-33, a mucosal alarmin known to elicit type-2 immunity, with infection and liver fibrosis profiles of school children from an endemic area for Schistosoma mansoni, malaria and hepatitis (B & C) in rural Cameroon. Methods: A cross-sectional study enrolling schoolchildren from 5 public schools was conducted. Single schistosomiasis, malaria and hepatitis infections or co-infections were assessed by kato katz, microscopy, and rapid diagnostic tests, respectively. Hepatic fibrosis was assessed by ultrasound according to WHO Niamey guidelines and plasma levels of Interleukin 33 were determined by ELISA. All statistics were performed using R studio software. Principal findings: We found a prevalence of 13.5% (37/275), 18.2% (50/275), and 8% (22/275), respectively for schistosomiasis, malaria and hepatitis (B or C) single infections. Only 7.6% (21/275) of co-infections were reported. Although Plasma IL-33 showed a minimal negative risk for schistosomiasis infection (AOR 0.99; 95% CI 0.97-1.01), S. mansoni infected participants had lower levels of plasma IL-33 (p = 0.003) which decreased significantly as eggs burdens increased (p = 0.01) with a negative Pearson coefficient of r = -0.22. Hepatic fibrosis occurred in 47.3% (130/275) of our study population independently from plasma levels of IL-33 (AOR 1.00; 95% CI 0.99-1.01). Conclusion/Significance: Our data failed to show an association between plasma IL-33 levels and liver disease but convincingly report on a negative association between plasma IL-33 levels and schistosomiasis infection and egg burden in school children from a polyparasitic schistosomiasis endemic area.

Host Regulators of Liver Fibrosis During Human Schistosomiasis.

Liver fibrosis is a wound-healing process purposely aimed at restoring organ integrity after severe injury caused by autoimmune reactions, mechanical stress or infections. The uncontrolled solicitation of this process is pathogenic and a pathognomonic feature of diseases like hepatosplenic schistosomiasis where exacerbated liver fibrosis is centrally positioned among the drivers of the disease morbidity and mortality. Intriguingly, however, liver fibrosis occurs and progresses dissimilarly in schistosomiasis-diseased individuals with the same egg burden and biosocial features including age, duration of residence in the endemic site and gender. This suggests that parasite-independent and currently poorly defined host intrinsic factors might play a defining role in the regulation of liver fibrosis, the hallmark of morbidity, during schistosomiasis. In this review, we therefore provide a comprehensive overview of all known host candidate regulators of liver fibrosis reported in the context of human schistosomiasis.

Schistosomiasis Burden and Its Association With Lower Measles Vaccine Responses in School Children From Rural Cameroon.

Background and Methods: Schistosomiasis is debilitating and reported to impair immune responsiveness of infected hosts. In Cameroon, mass drug administration (MDA) is used in schoolchildren to reduce transmission of S. haematobium and S. mansoni. The effects of MDA and the impact of schistosomiasis on the titers of antibodies in vaccinated children have been poorly studied. We therefore assessed the prevalence of schistosomiasis in schoolchildren, eight months after MDA, in two locations: Barombi Koto (BK), endemic for S. haematobium (N = 169) and Yoro (Y), endemic for S. mansoni (N = 356). Age, gender, residence time and frequency of contact with river water were assessed as risk factors for infection and morbidity in both localities. In 70 schoolchildren from BK and 83 from Y, ultrasound was used to assess morbidity according to the WHO guidelines. Evaluation of measles antibodies was performed in previously vaccinated schoolchildren (14 with S. haematobium and 12 egg-negative controls from BK and 47 with S. mansoni and12 egg-negative controls from Y). Principal Findings and conclusions: The prevalence of S. haematobium was 25. 4% in BK (43/169) and 34.8% for S. mansoni in Y (124/356), indicating the persistent transmission of schistosomiasis despite MDA. Older age (AOR 1.31; 95%CI 1.12-1.54) and higher frequencies of exposure to river water (AOR 1.99; 95%CI 1.03-3.86) were identified as risks for infection in BK whereas only older age (OR 1.15; 95%CI 1.04-1.27) was a risk for infection in Y. Bladder pathology (score 2 to 5) was observed in 29.2% (7/24) of egg-positive children in BK and liver pathology (pattern C) in 31.1% (19/61) of egg-positive children in Y. There was a positive correlation between S. haematobium egg burden and bladder pathology (AOR 1.01; 95% CI 0.99-1.02) and positive correlation between S. mansoni-driven liver pathology and female gender (AOR 3.01; 95% CI 0.88-10.26). Anti-measles antibodies in vaccinated children were significantly lower in S. mansoni-infected when compared to egg-negative controls (p = 0.001), which was not observed in the S. haematobium-infected group from BK. Our results demonstrate a questionable efficacy of MDA alone in halting schistosomiasis transmission and confirm a possible immunomodulatory effect of S. mansoni on response to vaccines.