Plasmodium falciparum parasites must invade red blood cells to survive within humans. Entry into red blood cells is governed by interactions between parasite adhesins and red blood cell receptors. ...Previously we identified that P. falciparum reticulocyte binding protein-like homologue 4 (PfRh4) binds to complement receptor 1 (CR1) to mediate entry of malaria parasites into human red blood cells. In this report we characterize a collection of anti-PfRh4 monoclonal antibodies and CR1 protein fragments that modulate the interaction between PfRh4 and CR1. We identify an anti-PfRh4 monoclonal that blocks PfRh4-CR1 interaction in vitro, inhibits PfRh4 binding to red blood cells, and as a result abolishes the PfRh4-CR1 invasion pathway in P. falciparum. Epitope mapping of anti-PfRh4 monoclonal antibodies identified distinct functional regions within PfRh4 involved in modulating its interaction with CR1. Furthermore, we designed a set of protein fragments based on extensive mutagenesis analyses of the PfRh4 binding site on CR1 and determined their interaction affinities using surface plasmon resonance. These CR1 protein fragments bind tightly to PfRh4 and also function as soluble inhibitors to block PfRh4 binding to red blood cells and to inhibit the PfRh4-CR1 invasion pathway. Our findings can aid future efforts in designing specific single epitope antibodies to block P. falciparum invasion via complement receptor 1.
Background: PfRh4 binds complement receptor 1 to mediate malaria parasite entry into red blood cells.
Results: Monoclonal antibodies and inhibitors either block or enhance PfRh4 interaction with complement receptor 1.
Conclusion: Identification was made of critical regions and residues within PfRh4 and CR1 that mediate successful P. falciparum entry.
Significance: Understanding functional regions within PfRh4 will aid in design of vaccine subunits.
The second most commonly mutated gene in primary microcephaly (MCPH) patients is wd40-repeat protein 62 (wdr62), but the relative contribution of WDR62 function to the growth of major brain lineages ...is unknown. Here, we use Drosophila models to dissect lineage-specific WDR62 function(s). Interestingly, although neural stem cell (neuroblast)-specific depletion of WDR62 significantly decreased neuroblast number, brain size was unchanged. In contrast, glial lineage-specific WDR62 depletion significantly decreased brain volume. Moreover, loss of function in glia not only decreased the glial population but also non-autonomously caused neuroblast loss. We further demonstrated that WDR62 controls brain growth through lineage-specific interactions with master mitotic signaling kinase, AURKA. Depletion of AURKA in neuroblasts drives brain overgrowth, which was suppressed by WDR62 co-depletion. In contrast, glial-specific depletion of AURKA significantly decreased brain volume, which was further decreased by WDR62 co-depletion. Thus, dissecting relative contributions of MCPH factors to individual neural lineages will be critical for understanding complex diseases such as microcephaly.
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•Glial-specific depletion of microcephaly protein WDR62 impairs brain growth•wdr62 depletion in glia causes neural stem cell (NSC) loss•WDR62 is required cell extrinsically in the NSC niche•Lineage-specific interactions between WDR62 and AURKA control brain growth
Quinn and colleagues use Drosophila models to demonstrate that depletion of microcephaly protein WDR62 specifically in the glial lineage impairs brain growth. Moreover, wdr62 depletion in glia not only impairs brain growth by decreasing the glial population but also leads to neural stem cell (NSC) loss. Thus, MCPH proteins are essential not only intrinsically for glial cell proliferation but are also required cell extrinsically for establishing the NSC niche.
Increasing evidence has suggested that hepatocellular carcinoma (HCC) might originate from a distinct subpopulation called cancer stem cells (CSCs), which are responsible for the limited efficacy of ...conventional therapies. We have previously demonstrated that granulin-epithelin precursor (GEP), a pluripotent growth factor, is upregulated in HCC but not in the adjacent non-tumor, and that GEP is a potential therapeutic target for HCC. Here, we characterized its expression pattern and stem cell properties in fetal and cancerous livers.
Protein expression of GEP in fetal and adult livers was examined in human and mouse models by immunohistochemical staining and flow cytometry. Liver cancer cell lines, isolated based on their GEP and/or ATP-dependent binding cassette (ABC) drug transporter ABCB5 expression, were evaluated for hepatic CSC properties in terms of colony formation, chemoresistance and tumorigenicity.
We demonstrated that GEP was a hepatic oncofetal protein that expressed in the fetal livers, but not in the normal adult livers. Importantly, GEP+ fetal liver cells co-expressed the embryonic stem (ES) cell-related signaling molecules including β-catenin, Oct4, Nanog, Sox2 and DLK1, and also hepatic CSC-markers CD133, EpCAM and ABCB5. Phenotypic characterization in HCC clinical specimens and cell lines revealed that GEP+ cancer cells co-expressed these stem cell markers similarly as the GEP+ fetal liver cells. Furthermore, GEP was shown to regulate the expression of ES cell-related signaling molecules β-catenin, Oct4, Nanog, and Sox2. Isolated GEP(high) cancer cells showed enhanced colony formation ability and chemoresistance when compared with the GEP(low) counterparts. Co-expression of GEP and ABCB5 better defined the CSC populations with enhanced tumorigenic ability in immunocompromised mice.
Our findings demonstrate that GEP is a hepatic oncofetal protein regulating ES cell-related signaling molecules. Co-expression of GEP and ABCB5 further enriches a subpopulation with enhanced CSC properties. The current data provide new insight into the therapeutic strategy.
Due to the anatomical peculiarity of the appendix,diagnosis of tumors arising from this area can be challenging by clinicoradiologic means.We report a case of a rare primary appendiceal signet ring ...carcinoma with an uncommon presentation.An 86-year-old woman was admitted toour hospital with subacute epigastric pain.Computed tomography demonstrated bowel wall thickening with fat stranding in the ileocecal region.The leading diagnostic consideration was inflammatory bowel disease.Upon colonoscopy,a swollen,distorted ileocecal valve was identified.The remaining colon was otherwise unremarkable.Extensive biopsy sampling of the ileocecal region and colon was performed.A lymphangitic signet ring carcinoma within the ileocecal region was diagnosed on biopsy;there was no dysplasia or carcinoma of the remaining biopsies.By cytomorphology and immunoprofile,a lymphangitic signet ring carcinoma of appendiceal origin was the primary consideration,further confirmed upon subsequent laparotomy.This case represents an unusual pattern of appendiceal tumor spread with localized,lymphangitic involvement,creating a milieu which closely simulates Crohn’s disease on imaging modalities.
mRNA vaccine technologies introduced following the SARS-CoV-2 pandemic have highlighted the need to better understand the interaction of adjuvants and the early innate immune response. Type I ...interferon (IFN-I) is an integral part of this early innate response that primes several components of the adaptive immune response. Women are widely reported to respond better than men to tri- and quadrivalent influenza vaccines. Plasmacytoid dendritic cells (pDCs) are the primary cell type responsible for IFN-I production, and female pDCs produce more IFN-I than male pDCs since the upstream pattern recognition receptor Toll-like receptor 7 (TLR7) is encoded by X chromosome and is biallelically expressed by up to 30% of female immune cells. Additionally, the TLR7 promoter contains several putative androgen response elements, and androgens have been reported to suppress pDC IFN-I
. Unexpectedly, therefore, we recently observed that male adolescents mount stronger antibody responses to the Pfizer BNT162b2 mRNA vaccine than female adolescents after controlling for natural SARS-CoV-2 infection. We here examined pDC behaviour in this same cohort to determine the impact of IFN-I on anti-spike and anti-receptor-binding domain IgG titres to BNT162b2. Through flow cytometry and least absolute shrinkage and selection operator (LASSO) modelling, we determined that serum-free testosterone was associated with reduced pDC IFN-I, but contrary to the well-described immunosuppressive role for androgens, the most bioactive androgen dihydrotestosterone was associated with increased IgG titres to BNT162b2. Also unexpectedly, we observed that co-vaccination with live attenuated influenza vaccine boosted the magnitude of IgG responses to BNT162b2. Together, these data support a model where systemic IFN-I increases vaccine-mediated immune responses, yet for vaccines with intracellular stages, modulation of the local IFN-I response may alter antigen longevity and consequently improve vaccine-driven immunity.
Family studies of antiviral immunity provide an opportunity to assess virus-specific immunity in infected and highly exposed individuals, as well as to examine the dynamics of viral infection within ...families. Transmission of SARS-CoV-2 between family members represented a major route for viral spread during the early stages of the pandemic, due to the nature of SARS-CoV-2 transmission through close contacts.
Here, humoral and cellular immunity is explored in 264 SARS-CoV-2 infected, exposed or unexposed individuals from 81 families in the United Kingdom sampled in the winter of 2020 before widespread vaccination and infection.
We describe robust cellular and humoral immunity into COVID-19 convalescence, albeit with marked heterogeneity between families and between individuals. T-cell response magnitude is associated with male sex and older age by multiple linear regression. SARS-CoV-2-specific T-cell responses in seronegative individuals are widespread, particularly in adults and in individuals exposed to SARS-CoV-2 through an infected family member. The magnitude of this response is associated with the number of seropositive family members, with a greater number of seropositive individuals within a family leading to stronger T-cell immunity in seronegative individuals.
These results support a model whereby exposure to SARS-CoV-2 promotes T-cell immunity in the absence of an antibody response. The source of these seronegative T-cell responses to SARS-CoV-2 has been suggested as cross-reactive immunity to endemic coronaviruses that is expanded upon SARS-CoV-2 exposure. However, in this study, no association between HCoV-specific immunity and seronegative T-cell immunity to SARS-CoV-2 is identified, suggesting that de novo T-cell immunity may be generated in seronegative SARS-CoV-2 exposed individuals.
Genetic disruptions of spindle/centrosome-associated WD40-repeat protein 62 (
WDR62
) are causative for autosomal recessive primary microcephaly (MCPH) and a broader range of cortical malformations. ...Since the identification of WDR62 as encoded by the MCPH2 locus in 2010, recent studies that have deleted/depleted WDR62 in various animal models of cortical development have highlighted conserved functions in brain growth. Here, we provide a timely review of our current understanding of WDR62 contributions in the self-renewal, expansion and fate specification of neural stem and progenitor cells that are critical for neocortical development. Recent studies have revealed multiple functions for WDR62 in the regulation of spindle organization, mitotic progression and the duplication and biased inheritance of centrosomes during asymmetric divisions. We also discuss recently elaborated WDR62 interaction partners that include Aurora and c-Jun N-terminal kinases as part of complex signalling mechanisms that may define its neural functions. These studies provide new insights into the molecular and cellular processes that are required for brain formation and implicated in the genesis of primary microcephaly.
This study investigates bilingual performance on the English and Spanish Boston Naming Tests (BNTs) while controlling for object familiarity and U.S. acculturation. Previous studies suggest that ...bilingualism negatively affects naming skill; however, object familiarity, which may be culturally influenced, and U.S. acculturation level have not been formally investigated. The current sample comprised 74 well-acculturated bilinguals and 52 English monolinguals. Participants judged their familiarity with BNT objects and later named the objects in either English or Spanish. Both groups rated BNT objects to be comparably familiar. However, bilinguals underperformed relative to monolinguals. In fact, those bilinguals born and raised in the USA and educated solely under English instruction were unable to match monolinguals' superior naming performance. These results underscore a language disadvantage in naming even for native-born, highly acculturated, English proficient bilinguals and suggest that the BNT is language specific and perhaps unsuitable for testing bilingual populations.
ObjectiveThe incidence of alcohol-associated liver disease (ALD) is increasing, and weight loss surgery is more common due to the obesity epidemic. Roux-en-Y gastric bypass (RYGB) is associated with ...alcohol use disorder and ALD; however, its impact on outcomes in patients hospitalised for alcohol-associated hepatitis (AH) is unclear.DesignWe performed a single-centre, retrospective study of patients with AH from June 2011 to December 2019. Primary exposure was the presence of RYGB. The primary outcome was inpatient mortality. Secondary outcomes included overall mortality, readmissions and cirrhosis progression.Results2634 patients with AH met the inclusion criteria; 153 patients had RYGB. Median age of the entire cohort was 47.3 years; median Model for End Stage Liver Disease - Sodium (MELD-Na) was 15.1 in the study group versus 10.9 in the control group. There was no difference in inpatient mortality between the two groups. On logistic regression, increased age, elevated body mass index, MELD-Na >20 and haemodialysis were all associated with higher inpatient mortality. RYGB status was associated with increased 30-day readmission (20.3% vs 11.7%, p<0.01), development of cirrhosis (37.5% vs 20.9%, p<0.01) and overall mortality (31.4% vs 24%, p=0.03).ConclusionsPatients with RYGB have higher rates of readmissions, cirrhosis and overall mortality after discharge from hospital for AH. Allocation of additional resources on discharge may improve clinical outcomes and reduce healthcare expenditure in this unique patient population.
The novel pro-drug of 3′4′-dihydroxyflavonol, NP202, potently reduces myocardial infarct size resulting from ischemia–reperfusion (I/R) through mechanisms that remain to be fully defined. In this ...study, we investigated whether cardioprotection induced by NP202 depended on activation of the reperfusion injury survival kinase (RISK) pathways. We therefore examined the effects of PD98059 and LY294002, specific inhibitors of the MEK/ERK1/2 and PI3K/Akt pathways, respectively. In isolated cardiomyocytes, H2O2induced oxidative stress activated ERK1/2 and this was further enhanced by DiOHF, the active parent compound of NP202. Although oxidative stress did not stimulate Akt in cardiomyocytes, co-treatment with DiOHF substantially increased Akt phosphorylation. This suggests that DiOHF is a potent modulator of RISK pathways specifically in the context of stress stimulation. In anesthetised sheep, following 1h ischemia and 3h reperfusion, the contribution of the RISK pathways to NP202-mediated cardioprotection was determined by treating the animals with PD98059, LY294002 or vehicle prior to NP202 administration and reperfusion. Infarct size, as a percentage of the area-at-risk, was substantially reduced by NP202 (from 78±6 to 46±4%, P<0.05). Inhibition of MEK/ERK1/2 abolished the cardioprotective effects of NP202 (infarct size 81±4%), whereas inhibition of PI3K/Akt had no effect (infarct size 53±4%). Our combined cellular and animal studies indicate that NP202 potently protects against myocardial I/R injury through complex mechanisms that involved augmentation of MEK/ERK1/2 signaling, but not PI3K/Akt signaling.
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