Structural and functional comparisons of salivary α-glucosidases from the mosquito vectors Aedes aegypti, Anopheles gambiae, and Culex quinquefasciatus

Mosquito vectors of medical importance both blood and sugar feed, and their saliva contains bioactive molecules that aid in both processes. Although it has been shown that the salivary glands of several mosquito species exhibit α-glucosidase activities, the specific enzymes responsible for sugar digestion remain understudied. We therefore expressed and purified three recombinant salivary α-glucosidases from the mosquito vectors Aedes aegypti, Anopheles gambiae, and Culex quinquefasciatus and compared their functions and structures. We found that all three enzymes were expressed in the salivary glands of their respective vectors and were secreted into the saliva. The proteins, as well as mosquito salivary gland extracts, exhibited α-glucosidase activity, and the recombinant enzymes displayed preference for sucrose compared to p-nitrophenyl-α-D-glucopyranoside. Finally, we solved the crystal structure of the Ae. aegypti α-glucosidase bound to two calcium ions at a 2.3 Ångstrom resolution. Molecular docking suggested that the Ae. aegypti α-glucosidase preferred di- or polysaccharides compared to monosaccharides, consistent with enzymatic activity assays. Comparing structural models between the three species revealed a high degree of similarity, suggesting similar functional properties. We conclude that the α-glucosidases studied herein are important enzymes for sugar digestion in three mosquito species.

Skin muscle is the initial site of viral replication for arboviral bunyavirus infection

The first step in disease pathogenesis for arboviruses is the establishment of infection following vector transmission. For La Crosse virus (LACV), the leading cause of pediatric arboviral encephalitis in North America, and other orthobunyaviruses, the initial course of infection in the skin is not well understood. Using an intradermal (ID) model of LACV infection in mice, we find that the virus infects and replicates nearly exclusively within skin-associated muscle cells of the panniculus carnosus (PC) and not in epidermal or dermal cells like most other arbovirus families. LACV is widely myotropic, infecting distal muscle cells of the peritoneum and heart, with limited infection of draining lymph nodes. Surprisingly, muscle cells are resistant to virus-induced cell death, with long term low levels of virus release progressing through the Golgi apparatus. Thus, skin muscle may be a key cell type for the initial infection and spread of arboviral orthobunyaviruses.

Complement receptor 1 is the human erythrocyte receptor for Plasmodium vivax erythrocyte binding protein

The discovery that Africans were resistant to infection by Plasmodium vivax (P. vivax) led to the conclusion that P. vivax invasion relied on the P. vivax Duffy Binding Protein (PvDBP) interacting with the Duffy Antigen Receptor for Chemokines (DARC) expressed on erythrocytes. However, the recent reporting of P. vivax infections in DARC-negative Africans suggests that the parasite might use an alternate invasion pathway to infect DARC-negative reticulocytes. To identify the parasite ligands and erythrocyte receptors that enable P. vivax invasion of both DARC-positive and -negative erythrocytes, we expressed region II containing the Duffy Binding-Like (DBL) domain of P. vivax erythrocyte binding protein (PvEBP-RII) and verified that the DBL domain binds to both DARC-positive and -negative erythrocytes. Furthermore, an AVidity-based EXtracelluar Interaction Screening (AVEXIS) was used to identify the receptor for PvEBP among over 750 human cell surface receptor proteins, and this approach identified only Complement Receptor 1 (CR1, CD35, or C3b/C4b receptor) as a PvEBP receptor. CR1 is a well-known receptor for P. falciparum Reticulocyte binding protein Homology 4 (PfRh4) and is present on the surfaces of both reticulocytes and normocytes, but its expression decreases as erythrocytes age. Indeed, PvEBP-RII bound to a subpopulation of both reticulocytes and normocytes, and this binding was blocked by the addition of soluble CR1 recombinant protein, indicating that CR1 is the receptor of PvEBP. In addition, we found that the Long Homology Repeat A (LHR-A) subdomain of CR1 is the only subdomain responsible for mediating the interaction with PvEBP-RII.

Aedes aegypti saliva modulates inflammasome activation and facilitates flavivirus infection in vitro

Mosquito borne flaviviruses such as dengue and Zika represent a major public health problem due to globalization and propagation of susceptible vectors worldwide. Vertebrate host responses to dengue and Zika infections include the processing and release of pro-inflammatory cytokines through the activation of inflammasomes, resulting in disease severity and fatality. Mosquito saliva can facilitate pathogen infection by downregulating the host's immune response. However, the role of mosquito saliva in modulating host innate immune responses remains largely unknown. Here, we show that mosquito salivary gland extract (SGE) inhibits dengue and Zika virus-induced inflammasome activation by reducing NLRP3 expression, Caspase-1 activation, and 1L-1β secretion in cultured human and mice macrophages. As a result, we observe that SGE inhibits virus detection in the early phase of infection. This study provides important insights into how mosquito saliva modulates host innate immunity during viral infection.

[Translated article] Latarjet procedure for shoulder instability: Implications in the innervation of the subscapularis muscle

INTRODUCTION

Our aim was to describe whether Latarjet's technique affects subscapularis muscle innervation.

MATERIALS AND METHODS

We studied 12 embalmed shoulders. Subscapularis muscle innervation pattern was registered. Dimensions of the subscapularis at the glenohumeral joint line and the nerves entry point were measured. Horizontal distances from the nerves to the glenohumeral joint line as well as vertical ones to the split were measured before and after Latarjet procedure. A safe zone for the split was designed to avoid damage to subscapularis innervation.

RESULTS

Subscapularis muscle is innervated by three principal branches: upper, middle, and inferior subscapularis nerves. No statistical differences were found between innervation distances before and after Latarjet procedure. To perform subscapularis split along the muscle safe zone, two thirds' proportions throughout all the split must be maintained.

CONCLUSIONS

Subscapularis muscle has a triple innervation and was not altered after Latarjet procedure. Therefore, Latarjet technique seems to respect subscapularis muscle innervation if its split is placed through the subscapularis muscle safe zone.

Latarjet procedure for shoulder instability: Implications in the innervation of the subscapularis muscle

INTRODUCTION

Our aim was to describe whether Latarjet's technique affects subscapularis muscle innervation.

MATERIALS AND METHODS

We studied 12 embalmed shoulders. Subscapularis muscle innervation pattern was registered. Dimensions of the subscapularis at the glenohumeral joint line and the nerves entry point were measured. Horizontal distances from the nerves to the glenohumeral joint line as well as vertical ones to the split were measured before and after Latarjet procedure. A safe zone for the split was designed to avoid damage to subscapularis innervation.

RESULTS

Subscapularis muscle is innervated by three principal branches: upper, middle, and inferior subscapularis nerves. No statistical differences were found between innervation distances before and after Latarjet procedure. To perform subscapularis split along the muscle safe zone, two thirds' proportions throughout all the split must be maintained.

CONCLUSIONS

Subscapularis muscle has a triple innervation and was not altered after Latarjet procedure. Therefore, Latarjet technique seems to respect subscapularis muscle innervation if its split is placed through the subscapularis muscle safe zone.

Antibodies to Aedes aegypti D7L salivary proteins as a new serological tool to estimate human exposure to Aedes mosquitoes

Introduction

Aedes spp. are the most prolific mosquito vectors in the world. Found on every continent, they can effectively transmit various arboviruses, including the dengue virus which continues to cause outbreaks worldwide and is spreading into previously non-endemic areas. The lack of widely available dengue vaccines accentuates the importance of targeted vector control strategies to reduce the dengue burden. High-throughput sensitive tools to estimate human-mosquito contact and evaluate vector control interventions are lacking. We propose a novel serological tool that allows rapid screening of large human cohorts for exposure to potentially infectious mosquitoes and effective targeting of vector control.

Methods

We tested 563 serum samples from a longitudinal pediatric cohort study previously conducted in Cambodia. Children enrolled in the study were dengue-naïve at baseline and were followed biannually for dengue incidence for two years. We used Western blotting and enzyme-linked immunosorbent assays to identify the most immunogenic Aedes aegypti salivary proteins and measure total anti- Ae. Aegypti IgG.

Results

We found a strong correlation (r s =0.86) between the combined IgG responses against AeD7L1 and AeD7L2 recombinant proteins and those to whole salivary gland homogenate. We observed seasonal fluctuations of AeD7L1+2 IgG responses, corresponding to Aedes spp. abundance in the region, and no cross-reactivity with Culex quinquefasciatus and Anopheles dirus mosquitoes. The baseline median AeD7L1+2 IgG responses for young children were higher in those who developed asymptomatic dengue versus those who developed symptomatic dengue.

Conclusion

The IgG response against AeD7L1+2 recombinant proteins is a highly sensitive and Aedes specific marker of human exposure to Aedes bites that can facilitate standardization of future serosurveys and epidemiological studies by its ability to provide a robust estimation of human-mosquito contact in a high-throughput fashion.

Interobserver reliability of classifying shoulder calcific tendinopathy on plain radiography and ultrasound

INTRODUCTION

Shoulder calcific tendinopathy is a frequent cause of shoulder pain. Diagnosis is usually based on ultrasound (US) and/or X-ray. US is considered an inherently operator-dependent imaging modality and, interobserver variability has previously been described by experts in the musculoskeletal US. The main objective of this study is to assess the interobserver agreement for shoulder calcific tendinopathy attending to the size, type, and location of calcium analyzed in plain film and ultrasound among trained musculoskeletal radiologists.

MATERIAL AND METHODS

From June 2018 to May 2019, we conducted a prospective study. Patients diagnosed with shoulder pain related to calcific tendinopathy were included. Two different experienced musculoskeletal radiologists evaluated independently the plain film and the US.

RESULTS

Forty patients, with a mean age of 54.6 years, were included. Cohen's kappa coefficient of 0.721 and 0.761 was obtained for the type of calcium encountered in plain film and the US, respectively. The location of calcification obtained a coefficient of 0.927 and 0.760 in plain film and US, respectively. The size of the calcification presented an intraclass correlation coefficient (ICC) of 0.891 and 0.86 in plain film and US respectively. No statistically significant differences were found in either measurement.

CONCLUSION

This study shows very good interobserver reliability of type and size measurement (plain film and US) of shoulder calcifying tendinopathy in experienced musculoskeletal radiologists.

Aedes aegypti D7 long salivary proteins modulate blood feeding and parasite infection

Mosquito saliva facilitates blood meal acquisition through pharmacologically active compounds that prevent host hemostasis and immune responses. Here, we generated two knockout (KO) mosquito lines by CRISPR/Cas9 to functionally characterize D7L1 and D7L2, two abundantly expressed salivary proteins from the yellow fever mosquito vector Aedes aegypti. The D7s bind and scavenge biogenic amines and eicosanoids involved in hemostasis at the bite site. The absence of D7 proteins in the salivary glands of KO mosquitoes was confirmed by mass spectrometry, enzyme-linked immunosorbent assay, and fluorescence microscopy of the salivary glands with specific antibodies. D7-KO mosquitoes had longer probing times than parental wildtypes. The differences in probing time were abolished when mutant mice resistant to inflammatory insults were used. These results confirmed the role of D7 proteins as leukotriene scavengers in vivo. We also investigated the role of D7 salivary proteins in Plasmodium gallinaceum infection and transmission. Both KO lines had significantly fewer oocysts per midgut. We hypothesize that the absence of D7 proteins in the midgut of KO mosquitoes might be responsible for creating a harsh environment for the parasite. The information generated by this work highlights the biological functionality of salivary gene products in blood feeding and pathogen infection. IMPORTANCE During blood feeding, mosquitoes inject saliva into the host skin, preventing hemostasis and inflammatory responses. D7 proteins are among the most abundant components of the saliva of blood-feeding arthropods. Aedes aegypti, the vector of yellow fever and dengue, expresses two D7 long-form salivary proteins: D7L1 and D7L2. These proteins bind and counteract hemostatic agonists such as biogenic amines and leukotrienes. D7L1 and D7L2 knockout mosquitoes showed prolonged probing times and carried significantly less Plasmodium gallinaceum oocysts per midgut than wild-type mosquitoes. We hypothesize that reingested D7s play a vital role in the midgut microenvironment with important consequences for pathogen infection and transmission.

Novel Radioenhancer NBTXR3 Activated by Radiotherapy in Cisplatin-Ineligible Locally Advanced HNSCC Patients: Final Results of a Phase I Trial

PURPOSE/OBJECTIVE(S)

New approaches are needed for frail or elderly patients with locally advanced head and neck squamous cell carcinoma (LA HNSCC) who are unfit to receive cisplatin with concurrent radiotherapy (RT). NBTXR3 is a first-in-class radioenhancer, composed of functionalized hafnium oxide nanoparticles, administered by a single intratumoral (IT) injection and activated by RT. NBTXR3 locally amplifies the anti-tumoral response of RT without adding toxicity to surrounding healthy tissue as shown in a randomized trial in soft tissue sarcoma. This two-part study: dose-escalation followed by the dose-expansion part reported here, evaluated the safety and preliminary efficacy for NBTXR3 activated by RT in elderly or frail patients ineligible to cisplatin.

MATERIALS/METHODS

This trial enrolled patients who had previously untreated AJCC 8th Stage III-IVA or T3, T4 SCC of the oral cavity or oropharynx (OPC) ineligible to cisplatin. Eligible patients received a single IT injection of NBTXR3 at the recommended dose (22% of the baseline tumor volume) followed by RT (IMRT 70 Gy in 35 fractions). The primary objectives of the dose expansion part were to test the recommended dose, to confirm its safety, and obtain preliminary evidence of efficacy. The secondary objectives included the evaluation of progression-free survival (PFS) and overall survival (OS).

RESULTS

Fifty-sixpatients in the dose expansion part were treated from April 2019-January 2022; 44 patients were evaluable for objective tumor response. In the all-treated population, median age was 71.9 years. 64.3% had age-adjusted Charlson Comorbidity Index scores ≥4, 55.4% had OPC (45.2% HPV+) and 80% had T3-4. Median injected volume of NBTXR3 was 13.6 [0.5-57.1] mL. Grade ≥ 3 adverse events reported as potentially related to NBTXR3 or to injection procedure were 1.2% and 0.4% of all AEs reported, respectively. In the evaluable population, the best objective response rate of the NBTXR3 injected lesion was 81.8% with a complete response rate of 63.6%. The best overall response rate (injected and non-injected lesions) was 79.5%. Final analyses on PFS and OS with long-term follow-up will be presented.

CONCLUSION

NBTXR3 IT injection followed by activation with RT was confirmed to be feasible and well tolerated in elderly or frail patients with LA HNSSC and significant comorbidities. The high rate of best overall response suggests that NBTXR3+RT is effective in this elderly population ineligible to cisplatin with a high unmet medical need. These results support our ongoing phase III study comparing NBTXR3/RT ± cetuximab vs. RT ± cetuximab in platinum-based chemotherapy ineligible elderly patients with LA-HNSCC: NANORAY 312 (NCIT04892173).

Implementation of a hybrid healthcare model in rheumatic musculoskeletal diseases: 6-months results of the multicenter Digireuma study

OBJECTIVES

Rheumatic and musculoskeletal diseases (RMDs) require a tailored follow-up that can be enhanced by the implementation of innovative tools. The Digireuma study aimed to test the feasibility of a hybrid follow-up utilizing an electronic patient reported outcomes (ePROs)-based monitoring strategy in patients with RMDs.

METHODS

Adult patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA) were recruited for a 6-month bicentric prospective follow-up consisting of face-to-face and digital assessments. Patients were asked to report disease-specific ePROs on a pre-established basis, and could also report flares, medication changes, and recent infections at any time. Four rheumatologists monitored these outcomes and contacted patients for interventions when deemed necessary. Results from face-to-face and digital assessments were described.

RESULTS

Of 56 recruited patients, 47 (84%) submitted any ePROs to the digital platform. Most patients with RA were female (74%, median age of 47 years), while 48% of patients with SpA were female (median age 40.4 years). A total of 3,800 platform visits were completed, with a median of 57 and 29 visits in patients with RA and SpA, respectively. Among 52 reported alerts, 47 (90%) needed contact, of which 36 (77%) were managed remotely. Adherence rates declined throughout the study, with around half of patients dropping out during the 6 months follow-up.

CONCLUSION

The implementation of a hybrid follow-up in clinical practice is feasible. Digital health solutions can provide granular knowledge of disease evolution and enable more informed clinical decision making, leading to improved patient outcomes. Further research is needed to identify target patient populations and engagement strategies.

Quantifying Fitness Costs in Transgenic Aedes aegypti Mosquitoes

Transgenic mosquitoes often display fitness costs compared to their wild-type counterparts. In this regard, fitness cost studies involve collecting life parameter data from genetically modified mosquitoes and comparing them to mosquitoes lacking transgenes from the same genetic background. This manuscript illustrates how to measure common life history traits in the mosquito Aedes aegypti, including fecundity, wing size and shape, fertility, sex ratio, viability, development times, male contribution, and adult longevity. These parameters were chosen because they reflect reproductive success, are simple to measure, and are commonly reported in the literature. The representative results quantify fitness costs associated with either a gene knock-out or a single insertion of a gene drive element. Standardizing how life parameter data are collected is important because such data may be used to compare the health of transgenic mosquitoes generated across studies or to model the transgene fixation rate in a simulated wild-type mosquito population. Although this protocol is specific for transgenic Aedes aegypti, the protocol may also be used for other mosquito species or other experimental treatment conditions, with the caveat that certain biological contexts may require special adaptations.

Guianensin, a Simulium guianense salivary protein, has broad anti-hemostatic and anti-inflammatory properties

Background

Salivary glands from blood-feeding arthropods secrete several molecules that inhibit mammalian hemostasis and facilitate blood feeding and pathogen transmission. The salivary functions from Simulium guianense, the main vector of Onchocerciasis in South America, remain largely understudied. Here, we have characterized a salivary protease inhibitor (Guianensin) from the blackfly Simulium guianense.

Materials and methods

A combination of bioinformatic and biophysical analyses, recombinant protein production, in vitro and in vivo experiments were utilized to characterize the molecula mechanism of action of Guianensin. Kinetics of Guianensin interaction with proteases involved in vertebrate inflammation and coagulation were carried out by surface plasmon resonance and isothermal titration calorimetry. Plasma recalcification and coagulometry and tail bleeding assays were performed to understand the role of Guianensin in coagulation.

Results

Guianensin was identified in the sialotranscriptome of adult S. guianense flies and belongs to the Kunitz domain of protease inhibitors. It targets various serine proteases involved in hemostasis and inflammation. Binding to these enzymes is highly specific to the catalytic site and is not detectable for their zymogens, the catalytic site-blocked human coagulation factor Xa (FXa), or thrombin. Accordingly, Guianensin significantly increased both PT (Prothrombin time) and aPTT (Activated partial thromboplastin time) in human plasma and consequently increased blood clotting time ex vivo. Guianensin also inhibited prothrombinase activity on endothelial cells. We show that Guianensin acts as a potent anti-inflammatory molecule on FXa-induced paw edema formation in mice.

Conclusion

The information generated by this work highlights the biological functionality of Guianensin as an antithrombotic and anti-inflammatory protein that may play significant roles in blood feeding and pathogen transmission.

[Translated article] Comparative biomechanical study of two configurations of cemented screws in a simulated proximal humerus fracture fixed with locking plate

INTRODUCTION

Screw tip augmentation with bone cement for fixation of osteoporotic proximal humerus fractures seems to improve stability and to decrease the rate of complications related to implant failure. However, the optimal augmentation combinations are unknown. The aim of this study was to assess the relative stability of two augmentations combinations under axial compression load in a simulated proximal humerus fractures fixed with locking plate.

MATERIAL AND METHODS

A surgical neck osteotomy was created in five pairs of embalmed humeri with a mean age of 74 years (range 46-93 years), secured with a stainless-steel locking-compression plate. In each pair of humeri, on the right humerus were cemented the screws A and E, and in the contralateral side were cemented screws B and D of the locking plate. The specimens were first tested cyclically in axial compression for 6000 cycles to evaluate interfragmentary motion (dynamic study). At the end of the cycling test, the specimens were loaded in compression force simulating varus bending with increasing load magnitude until failure of the construct (static study).

RESULTS

There were no significant differences in interfragmentary motion between the two configurations of cemented screws in the dynamic study (p=0.463). When tested to failure, the configuration of cemented screws in lines B and D demonstrated higher compression load to failure (2218N vs. 2105, p=0.901) and higher stiffness (125N/mm vs. 106N/mm, p=0.672). However, no statistically significant differences were reported in any of these variables.

CONCLUSIONS

In simulated proximal humerus fractures, the configuration of the cemented screws does not influence the implant stability when a low-energy cyclical load is applied. Cementing the screws in rows B and D provides similar strength to the previously proposed cemented screws configuration and could avoid complications observed in clinical studies.

Evaluation of Aedes aegypti Penetration, Probing, and Feeding Times on Mice

In mosquitoes, the intradermal search for vertebrate blood (probing time) corresponds to the time taken from initial insertion of the mouthparts in the skin until visualization of the initial engorgement of blood in the midgut. Probing time evaluation provides useful information on the ability of a mosquito to initiate successful blood feeding. In this protocol, we describe how to determine feeding parameters in Aedes aegypti, a widely distributed mosquito that transmits several deadly pathogens, including yellow fever, dengue, Zika, and Chikungunya viruses. We focus on the different steps of a blood feeding event, including penetration, probing, interprobing, and feeding time. Penetration time corresponds to the insertion of the stylets into the host skin and usually lasts <10 sec. Probing time or intradermal search for blood involves saliva secretion into the skin. Some researchers group penetration and probing time as the exploratory phase for blood. Feeding time is an active phase of blood ingestion and engorgement. Feeding parameters depend on mosquito behaviors and these measurements are visually taken by the investigator. We include a video that provides a close look at a mosquito feeding event in which penetration, probing, and feeding times can be observed. To record these experimental times, one must closely watch the mosquito feeding behavior including stylet penetration in the host skin, visualization of the first traces of blood in the midgut, engorgement of the midgut, and removal of stylets from the skin.

Evaluation of Aedes aegypti Feeding Status

Female mosquitoes need vertebrate blood for egg development. Evaluating mosquito behavior is essential for determining the ability of a mosquito to blood feed. Blood feeding experiments are often performed using artificial membrane feeders; however, such experiments do not represent realistic scenarios in which a mosquito injects saliva into the host to prevent host hemostatic responses. Vertebrate animal models are therefore more representative of a natural blood feeding event. Here, we describe a methodology to evaluate mosquito blood feeding success that can be used to compare blood feeding between mosquito groups-for instance, wild-type versus transgenic mosquitoes lacking salivary proteins or field-collected versus laboratory-reared mosquitoes. We also include a simple procedure to measure blood meal size, allowing for a more quantitative assessment of feeding status. The volume of ingested blood directly affects mosquito fecundity and fertility, important markers of fitness. The methods described herein can be used to evaluate transmission-blocking vaccines, insecticides, or fitness costs associated with transgenic mosquitoes.

Determination of Mosquito Probing and Feeding Time to Evaluate Mosquito Blood Feeding

Hematophagous arthropods are animals that feed on vertebrate blood for egg production. Mosquitoes must pierce the host skin, locate blood vessels, and extract blood without being noticed. Mosquito stylets lacerate host tissues, triggering the activation of the three branches of hemostasis, or stopping of blood flow: vasoconstriction, platelet aggregation, and coagulation. Mosquitoes inject saliva into the host skin during their intradermal search for blood (also called probing), and salivary proteins counteract hemostasis. Blood feeding dynamics have been traditionally described by observational studies, in which researchers using magnifying glasses watched mosquitoes in the act of blood feeding. These studies provided the foundation for protocols to evaluate mosquito blood feeding in a more quantitative manner. Here, we introduce mosquito blood feeding biology with a focus on the feeding steps, which include penetration, probing, and feeding. Understanding blood feeding dynamics is crucial for evaluating probing time and other relevant parameters derived from blood feeding, such as blood meal size, fecundity, and fertility. Other considerations, including the relationship between probing and pathogen transmission and novel technologies to address blood feeding, are also discussed.

Anopheles salivary apyrase regulates blood meal hemostasis and drives malaria parasite transmission

Mosquito salivary proteins play a crucial role in regulating hemostatic responses at the bite site during blood feeding. In this study, we investigate the function of Anopheles gambiae salivary apyrase (AgApyrase) in Plasmodium transmission. Our results demonstrate that salivary apyrase interacts with and activates tissue plasminogen activator, facilitating the conversion of plasminogen to plasmin, a human protein previously shown to be required for Plasmodium transmission. Microscopy imaging shows that mosquitoes ingest a substantial amount of apyrase during blood feeding which reduces coagulation in the blood meal by enhancing fibrin degradation and inhibiting platelet aggregation. Supplementation of Plasmodium infected blood with apyrase significantly enhanced Plasmodium infection in the mosquito midgut. In contrast, AgApyrase immunization inhibited Plasmodium mosquito infection and sporozoite transmission. This study highlights a pivotal role for mosquito salivary apyrase for regulation of hemostasis in the mosquito blood meal and for Plasmodium transmission to mosquitoes and to the mammal host, underscoring the potential for new strategies to prevent malaria transmission.

A phase I trial of LXS196, a protein kinase C (PKC) inhibitor, for metastatic uveal melanoma

BACKGROUND

Up to 50% of patients with uveal melanoma develop metastases (MUM) with a poor prognosis and median overall survival of approximately 1 year.

METHODS

This phase I study evaluated the safety, tolerability, pharmacokinetics, pharmacodynamics and efficacy of the oral protein kinase C inhibitor LXS196 in 68 patients with MUM (NCT02601378). Patients received LXS196 doses ranging from 100-1000 mg once daily (QD; n = 38) and 200-400 mg twice daily (BID; n = 30).

RESULTS

First cycle dose-limiting toxicities (DLTs) were observed in 7/38 (18.4%) QD and 2/17 (11.8%) BID patients. Hypotension was the most common DLT, occurring at doses ≥500 mg/day, and manageable with LXS196 interruption and dose reduction. Median duration of exposure to LXS196 was 3.71 months (range: 1.81-15.28) for QD and 4.6 months (range: 0.33-58.32) for BID dosing. Clinical activity was observed in 6/66 (9.1%) evaluable patients achieving response (CR/PR), with a median duration of response of 10.15 months (range: 2.99-41.95); 45/66 had stable disease (SD) per RECIST v1.1. At 300 mg BID, the recommended dose for expansion, 2/18 (11.1%) evaluable patients achieved PR and 12/18 (66.7%) had SD.

CONCLUSION

These results suggest manageable toxicity and encouraging clinical activity of single-agent LXS196 in patients with MUM.

A deeper insight into the sialome of male and female Culex quinquefasciatus mosquitoes

INTRODUCTION

During evolution, blood-feeding arthropods developed a complex salivary mixture that can interfere with host haemostatic and immune response, favoring blood acquisition and pathogen transmission. Therefore, a survey of the salivary gland contents can lead to the identification of molecules with potent pharmacological activity in addition to increase our understanding of the molecular mechanisms underlying the hematophagic behaviour of arthropods. The southern house mosquito, Culex quinquefasciatus, is a vector of several pathogenic agents, including viruses and filarial parasites that can affect humans and wild animals.

RESULTS

Previously, a Sanger-based transcriptome of the salivary glands (sialome) of adult C. quinquefasciatus females was published based on the sequencing of 503 clones organized into 281 clusters. Here, we revisited the southern mosquito sialome using an Illumina-based RNA-sequencing approach of both male and female salivary glands. Our analysis resulted in the identification of 7,539 coding DNA sequences (CDS) that were functionally annotated into 25 classes, in addition to 159 long non-coding RNA (LncRNA). Additionally, comparison of male and female libraries allowed the identification of female-enriched transcripts that are potentially related to blood acquisition and/or pathogen transmission.

CONCLUSION

Together, these findings represent an extended reference for the identification and characterization of the proteins containing relevant pharmacological activity in the salivary glands of C. quinquefasciatus mosquitoes.

The salivary protein Saglin facilitates efficient midgut colonization of Anopheles mosquitoes by malaria parasites

Malaria is caused by the unicellular parasite Plasmodium which is transmitted to humans through the bite of infected female Anopheles mosquitoes. To initiate sexual reproduction and to infect the midgut of the mosquito, Plasmodium gametocytes are able to recognize the intestinal environment after being ingested during blood feeding. A shift in temperature, pH change and the presence of the insect-specific compound xanthurenic acid have been shown to be important stimuli perceived by gametocytes to become activated and proceed to sexual reproduction. Here we report that the salivary protein Saglin, previously proposed to be a receptor for the recognition of salivary glands by sporozoites, facilitates Plasmodium colonization of the mosquito midgut, but does not contribute to salivary gland invasion. In mosquito mutants lacking Saglin, Plasmodium infection of Anopheles females is reduced, resulting in impaired transmission of sporozoites at low infection densities. Interestingly, Saglin can be detected in high amounts in the midgut of mosquitoes after blood ingestion, possibly indicating a previously unknown host-pathogen interaction between Saglin and midgut stages of Plasmodium. Furthermore, we were able to show that saglin deletion has no fitness cost in laboratory conditions, suggesting this gene would be an interesting target for gene drive approaches.

An insight into the female and male Sabethes cyaneus mosquito salivary glands transcriptome

Mosquitoes are responsible for the death and debilitation of millions of people every year due to the pathogens they can transmit while blood feeding. While a handful of mosquitoes, namely those in the Aedes, Anopheles, and Culex genus, are the dominant vectors, many other species belonging to different genus are also involved in various pathogen cycles. Sabethes cyaneus is one of the many poorly understood mosquito species involved in the sylvatic cycle of Yellow Fever Virus. Here, we report the expression profile differences between male and female of Sa.cyaneus salivary glands (SGs). We find that female Sa.cyaneus SGs have 165 up-regulated and 18 down-regulated genes compared to male SGs. Most of the up-regulated genes have unknown functions, however, odorant binding proteins, such as those in the D7 protein family, and mucins were among the top 30 genes. We also performed various in vitro activity assays of female SGs. In the activity analysis we found that female SG extracts inhibit coagulation by blocking factor Xa and has endonuclease activity. Knowledge about mosquitoes and their physiology are important for understanding how different species differ in their ability to feed on and transmits pathogens to humans. These results provide us with an insight into the Sabethes SG activity and gene expression that expands our understanding of mosquito salivary glands.

Oncology phase I trial design and conduct: time for a change - MDICT Guidelines 2022

In 2021, the Food and Drug Administration Oncology Center of Excellence announced Project Optimus focusing on dose optimization for oncology drugs. The Methodology for the Development of Innovative Cancer Therapies (MDICT) Taskforce met to review and discuss the optimization of dosage for oncology trials and to develop a practical guide for oncology phase I trials. Defining a single recommended phase II dose based on toxicity may define doses that are neither the most effective nor the best tolerated. MDICT recommendations address the need for robust non-clinical data which are needed to inform trial design, as well as an expert team including statisticians and pharmacologists. The protocol must be flexible and adaptive, with clear definition of all endpoints. Health authorities should be consulted early and regularly. Strategies such as randomization, intrapatient dose escalation, and real-world eligibility criteria are encouraged whereas serial tumor sampling is discouraged in the absence of a strong rationale and appropriately validated assay. Endpoints should include consideration of all longitudinal toxicity. The phase I dose escalation trial should define the recommended dose range for later testing in randomized phase II trials, rather than a single recommended phase II dose, and consider scenarios where different populations may require different dosages. The adoption of these recommendations will improve dosage selection in early clinical trials of new anticancer treatments and ultimately, outcomes for patients.

Streamlining clinical research: an ESMO awareness call to improve sponsoring and monitoring of clinical trials

BACKGROUND

During recent years, the burden of bureaucracy in clinical research has increased dramatically, adversely impacting the activity of investigators and clinical research teams. Although compliance with the Declaration of Helsinki, the guidelines for Good Clinical Practice (GCP), and other applicable regulations remains unquestionable, their overinterpretation and substitution by the internal operating procedures of sponsors and Contract Research Organizations (CROs) have increased the administrative burden. A survey conducted by the European Society for Medical Oncology (ESMO) Clinical Research Observatory (ECRO) among 940 investigators confirmed that they considered that the administrative burden in clinical research is excessive; that administrative procedures could be reduced without affecting the safety and the rights of the patients and the quality of the data; and that bureaucracy represents an obstacle for clinical research.

METHODS

A panel of physicians with extensive experience in clinical research, composed by members of the ECRO and the ESMO Scientific Medical and Public Policy divisions, analyzed clinical trial procedures related to administrative workflow, pharmacovigilance, and medical care.

RESULTS

The panel identified situations that generate debate between investigators and sponsors/CROs and selected real clinical scenarios that exemplify such situations. The panel discussed and proposed specific recommendations for those situations, based on GCP.

CONCLUSIONS

This initiative aspires to streamline clinical research procedures and to become a platform for discussion among all clinical trial stakeholders, with the aim of promoting the sustainability of clinical research and the care of cancer patients.

A Simple Method for Immunohistochemistry and Imaging of Mosquito Salivary Glands

Immunohistochemistry is a valuable technique that provides information on protein localization and interactions in tissues. Mosquito salivary gland immunohistochemistry requires the meticulous dissection of a delicate tissue. The integrity of the salivary glands must be closely monitored throughout the entire process to prevent structural damage and loss of saliva. This protocol describes a series of simple steps to perform salivary gland immunohistochemistry including tissue dissection, permeabilization, immunostaining, mounting, and imaging by confocal microscopy.

In heart failure, self-care behavior is an independent determinant of health-related quality of life, regardless of the severity of this patients

Background

Poor self-care behaviour is associated with a higher risk of readmission and mortality in patients with heart failure (HF). The interplay between self-care and patient-reported outcomes such as health-related quality of life (QoL) has not been fully established.

Purpose

To describe the association between self-care and QoL in real-world cohort of HF patients.

Methods

We conducted an observational, prospective, cohort study of 1120 consecutive patients with chronic HF. We used the modified European Heart Failure Self-care Behaviour Scale 9-item version (EHFSCBS-9) to measure self-care. Scores were inverted and standardized (higher scores indicate better selfcare). To assess QoL, we used the Minnesota Living with Heart Failure Questionnaire (MLHFQ) (higher scores indicate worse QoL). Written informed consent, complete clinical and psychosocial information of patients were obtained at baseline. To determine the impact of global self-care and its dimensions (autonomy-based adherence, consulting behaviour and provider-based adherence), multivariate linear regressions models (backwards stepwise methods) to predict

QoL were constructed. The multivariate parametric and non-parametric associations between EHFSCBS-9 scoresand the β estimated risk of impairment of QoL (defined as MLHFQ scores ≥ median values) were explored using General Additive Models (GAM). All models were adjusted by age, sex and prognostic factors such as LVEF, NYHA, NT-proBNP levels and recent hospitalization among other well-known determinants of HF severity.

Results

A total of 484 patients (43%) were women, mean age was 72±11 years, and mean LVEF was 45±17%. Mean MLHFQ scores were 45±24. Mean EHFSCBS-9 scores were 69±28. There was a significant inverse correlation between EHFScBS-9 and MLHFQ scores (r=−0.158; p-value&lt;0.0001). As shown in Table 1, self-care behaviour and its 3 domains were independent predictors of QoL in 7 out of the 16 associations explored. These models confirmed a weak linear relationship between EHFSCBS-9 scores and MLHFQ scores particularly between global selfcare and consulting behaviour dimension with global, emotional and social dimensions of QoL. Interestingly, when QoL was dichotomized as impaired/preserved QoL, GAM showed a significant non-parametric “U-shape” relationship (p-value&lt;0.05) between EHFScBS-9 scores and the risk of impairment in QoL (Figure 1).

Conclusions

We have shown that self-care behaviour is an independent predictor of health related QoL in HF regardless the level of disease severity. Global self-care and consulting behaviour were particularly and significantly associated with global QoL and emotional and social dimensions of QoL. Interestingly the relationship between self-care scores and the risk of impaired global QoL was non-linear showing a “U-shape” association pointing out that patients with extreme levels of self-care were more likely to experience impairments in QoL.

Funding Acknowledgement

Type of funding sources: None.

Performing Immunohistochemistry in Mosquito Salivary Glands

Studying protein localization in mosquito salivary glands provides novel insights on the function and physiological relevance of salivary proteins and also provides an avenue to study interactions between mosquitoes and pathogens. Salivary proteins display compartmentalization. For example, proteins involved in blood feeding are stored in the medial and distal lateral lobes, whereas proteins related to sugar metabolism localize to the proximal portion of the lateral lobes. Immunohistochemistry assays use antibodies raised against recombinant salivary proteins to reveal the protein localization and interactions within the tissue. In this assay, permeabilization of the salivary glands allows the antibodies to enter the cells and bind their target proteins. The primary antibody-antigen complexes are later marked with fluorescently labeled secondary antibodies. Antibodies that recognize pathogen-specific proteins can also be incorporated in these assays, providing information about pathogen localization within the salivary glands or pathogen interactions with mosquito salivary proteins. Here, we introduce immunohistochemistry assays for use in mosquito salivary glands.

Fragility influences the impact of self-care behavior on patient-reported outcomes further of psychosocial factors of self-perceived health status in patients with heart failure

Background

Poor self-care behaviour is associated with a higher risk of readmission and mortality in patients with heart failure (HF). Psychosocial factors are key determinants of patient-reported outcomes (PROMs) such as health-realted quality of life (QoL). Little is known about the interplay between self-care and psychosocial factors on PROMs in HF.

Purpose

To describe the interaction of self-care and psycho-social factors on QoL in a real-world cohort of HF patients.

Methods

We conducted an observational, prospective, cohort study of 1120 consecutive patients with chronic. We used the modified European Heart Failure Self-care Behaviour Scale 9-item version (EHFSCBS-9) to measure self-care (inverted and standardised: higher scores indicate better self-care). To assess QoL, we used Minnesota Living with Heart Failure Questionnaire (MLHFQ) (higher scores indicate worse QoL). General linear models (GLM) were constructed to explore the interaction between psychosocial factors and poor self-care (defined as EHFSCBS-9 ≤lower tertile) on adjusted MLHFQ scores. To determine the impact of self-care, multivariate linear regressions models to predict QoL were constructed stratified according to selected psycho-social determinants. All models were adjusted by age, sex and psycho-social determinants of QoL including literacy, cognitive function (Pfeiffer test), dependency (Barthel and Lawton & Brody test), social support (Duke UNC and APGAR Familyfunction), depressive symptoms (15-item Geriatric Depression Scale) and fragility (Barber test scores ≥1).

Results

A total of 484 patients (43%) were women, mean age was 72±11 years, and mean LVEF was 45±17%. Mean MLHFQ scores were 45±24. Mean EHFSCBS-9 scores were 69±28. There was a significant inverse correlation between EHFScBS-9 and MLHFQ scores (r=−0.158; p-value &lt;0.0001). Fragility was present in 883 patients (79%). In adjusted GLM, poor self-care (F=10.2; p-value=0.001) and fragility (F=17.9; p-value &lt;0.001) were independent predictors of higher adjusted scores in the MLHFQ indicating worse QoL. As shown in Figure 1, the interaction between fragility and self-care was significant (F=6.8; p-value = 0.009). Linear regression models (Table 1) stratified according the absence (panel A) or the presence (panel B) of fragility showed that fragility modulated the association between self-care behaviour and QoL. Only in patients without fragility, self-care were independent predictors of QoL. On the other hand, in patients with fragility, self-care behaviour did not longer influence self-perceived health status in patients with HF.

Conclusions

We have shown that self-care behaviour is an independent predictor of PROMs in HF regardless the presence of important psycho-social determinants of QoL only when fragility status is taken into account. Fragility modulates the influence of self-care and QoL, including each one of its dimensions.

Funding Acknowledgement

Type of funding sources: None.

DAMOCLES project show that cognitive function is a strong determinant of the influence of self-care behavior on health-related quality of life in patients with heart failure

Background

Poor self-care is associated with a poorer outcomes in patients with heart failure (HF). Psycho-social factors are determinants of patient-reported outcomes (PROMs) such as health-realted quality of life (QoL). However, little is known about the interplay between self-care and psychosocial factors such as cognitive function on PROMs in patients with HF.

Purpose

Describe the effect of self-care on QoL across cognitive function and explore whether the interaction between self-care and cognitive function may account for this effect.

Methods

1120 patients with chronic HF from DAMOCLES study were analyzed. We used the modified European Heart Failure Self-care Behaviour Scale 9-item version (EHFSCBS-9) to measure self-care (inverted and standardised: higher scores indicate better self-care). To assess QoL, we used Minnesota Living with Heart Failure Questionnaire (MLHFQ) (higher scores indicate worse QoL). Cognitive function was evaluated using Mini-Mental State Examination (MMSE) and Short Portable Mental State Questionnaire (SPMSQ) Tests. Cognitive impairment was defined as abnormal age-and-literacy-adjusted scores. General linear models (GLM) were constructed to explore the interaction between cognitive function and poor self-care (defined as EHFSCBS-9 ≤lower tertile) on adjusted MLHFQ scores. To determine the impact self-care, multivariate linear regressions models to predict QoL were constructed stratified according to cognitive function. All models were adjusted by determinants of HF severity.

Results

Mean age was 72±11 years, 43% were women and mean LVEF was 45±17%. Lower MMSE scores (β=−0,163; p-value &lt;0.001) and &gt;3 errors in the SPMSQ indicating cognitive impairment (β=0.071; p-value = 0.023) were associated with higher scores in the MLHFQ. These associations were confirmed in multivariare linear regression models (β=0.062; p-value = 0.038). In adjusted GLM, poor global self-care (F=4.8; p-value = 0.029) was an independent predictor of higher adjusted scores in the MLHFQ. Interaction term poor self-care by cognitive impairment was significantly associated with MLHFQ scores (F=6.0; p-value=0.014; Figure 1). Multivariate linear regresion models (Table 1) stratified according the absence (panel A) or the presence (panel B) of cognitive impairment showed that cognitive function modulates the association between self-care behaviour and QoL. This effect was only seen in patients without cognitive impairment. In patients with cognitive dysfunction, self-care behaviour did not longer influence self-perceived health status in patients with HF.

Conclusions

Self-care behaviour is an independent predictor of PROMs in HF regardless cognitive disfunction. Cognitive function modulates 1) influence of global self-care and each one of its dimensions on emotional QoL and 2) impact of global self-care and consulting behaviour on global and social QoL.

Funding Acknowledgement

Type of funding sources: None.

In patients with chronic heart failure, there have been no gender differences in the impact of self behavior on patient-reported outcomes

Background

Poor self-care behaviour is associated with a higher risk in heart failure (HF). Gender is a determinant of patient-reported outcomes (PROMs) such as health-realted quality of life (QoL) in HF. Female gender is consistently associated with worse QoL. Whether gender may influence the effect of self-care on PROMS is not known.

Purpose

Describe the effect of self-care on QoL according to gender in a real world cohort of HF patients.

Methods

1120 patients with chronic HF were analysed. We used the modified European Heart Failure Self-care Behaviour Scale 9-item version (EHFSCBS-9) to measure self-care (inverted and standardised: higher scores indicate better self-care). To assess QoL, we used Minnesota Living with Heart Failure Questionnaire (MLHFQ) (higher scores indicate worse QoL). General linear models (GLM) were constructed to explore the interaction between gender and poor self-care (defined as EHFSCBS-9 ≤lower tertile) on adjusted MLHFQ scores. To determine the impact of global self-care and its dimensions, multivariate linear regressions models to predict QoL were constructed stratified according to gender. All models were adjusted by determinants of HF severity.

Results

Mean age was 72±11 years, 43% were women and mean LVEF was 45±17%. There was a significant inverse correlation between EHFScBS-9 and MLHFQ scores (r=−0.158; p-value&lt;0.0001). Unadjusted MLHFQ scores were consistenly higher in women compared to men (49±23 vs. 43±24; p-value&lt;0.001). In adjusted GLM, female gender (F=4.8; p-value=0.028) and poor global self-care (F=12.6; p-value&lt;0.001) were independent predictors of higher adjusted scores in MLHFQ, indicating worse global QoL. As shown in Figure 1, the interaction term gender by poor self-care was not significantly associated with MLHFQ scores in adjusted GLM (F=0.018; p-value=0.893): the gap between women and men in terms of QoL was observed in both self-care strata and the effect of self care on QoL was observed in both genders. Multivariate linear regresion models (Table 1) stratified according to female gender (panel A) or male gender (panel B) showed that higher scores in the EHFScBS-9 were associated with lower scores in the MLHFQ in women and men. This effect (Table 1) was equally seen in both genders for global QoL and was driven by global self-care, consulting behaviour, and in a lesser extent by autonomy-baseda dherence. The physical dimension of QoL was not affected by self-care in either women or men except for consulting behaviour.

Conclusions

Self-care is an independent predictor of health-related QoL in HF, regardless of the level of disease severity. Global self-care, autonomy-based adherence and consulting behaviour were particularly associated with global QoL and emotional and social dimensions of QoL in women and men. In both genders, the effect of self-care on QoL was driven by its effect on emotional and social dimensions. Provider-based adherence did not influence QoL.

Funding Acknowledgement

Type of funding sources: None.

Isatuximab plus atezolizumab in patients with advanced solid tumors: results from a phase I/II, open-label, multicenter study

BACKGROUND

The anti-CD38 antibody isatuximab is approved for the treatment of relapsed/refractory multiple myeloma, but there are no data on its efficacy in solid tumors. This phase I/II study (NCT03637764) assessed the safety and activity of isatuximab plus atezolizumab (Isa + Atezo), an anti-programmed death-ligand 1 (PD-L1) antibody, in patients with immunotherapy-naive solid tumors: epithelial ovarian cancer (EOC), glioblastoma (GBM), hepatocellular carcinoma (HCC), and squamous cell carcinoma of the head and neck (SCCHN).

PATIENTS AND METHODS

Phase I assessed safety, tolerability, pharmacokinetics, pharmacodynamics, and the recommended phase II dose (RP2D) of isatuximab 10 mg/kg intravenously (i.v.) every week for 3 weeks followed by once every 3 weeks + atezolizumab 1200 mg i.v. every 3 weeks. Phase II used a Simon's two-stage design to assess the overall response rate or progression-free survival rate at 6 months (GBM cohort). Interim analysis was carried out at 6 months following first dose of the last enrolled patient in each cohort. Pharmacodynamic biomarkers were tested for CD38, PD-L1, tumor-infiltrating immune cells, and FOXP3+ regulatory T cells (Tregs) in the tumor microenvironment (TME).

RESULTS

Overall, 107 patients were treated (EOC, n = 18; GBM, n = 33; HCC, n = 27; SCCHN, n = 29). In phase I, Isa + Atezo showed an acceptable safety profile, no dose-limiting toxicities were observed, and RP2D was confirmed. Most patients experienced ≥1 treatment-emergent adverse event (TEAE), with ≤48.5% being grade ≥3. The most frequent TEAE was infusion reactions. The study did not continue to stage 2 based on prespecified targets. Tumor-infiltrating CD38+ immune cells were reduced and almost cleared after treatment. Isa + Atezo did not significantly modulate Tregs or PD-L1 expression in the TME.

CONCLUSIONS

Isa + Atezo had acceptable safety and tolerability. Clinical pharmacodynamic evaluation revealed efficient target engagement of isatuximab via treatment-mediated reduction of CD38+ immune cells in the TME. Based on clinical data, CD38 inhibition does not improve responsiveness to PD-L1 blockade in these patients.

A deeper insight into the sialome of male and female Ochlerotatus triseriatus mosquitoes

Over the last 20 years, advancements in sequencing technologies have highlighted the unique composition of the salivary glands of blood-feeding arthropods. Further biochemical and structural data demonstrated that salivary proteins can disrupt host hemostasis, inflammation and immunity, which favors pathogen transmission. Previously, a Sanger-based sialome of adult Ochlerotatus triseriatus female salivary glands was published based on 731 expressed sequence tag (ESTs). Here, we revisited O. triseriatus salivary gland contents using an Illumina-based sequencing approach of both male and female tissues. In the current data set, we report 10,317 DNA coding sequences classified into several functional classes. The translated transcripts also served as a reference database for proteomic analysis of O. triseriatus female saliva, in which unique peptides from 101 proteins were found. Finally, comparison of male and female libraries allowed for the identification of female-enriched transcripts that are potentially related to blood acquisition and virus transmission.

Scintillation light detection in the 6-m drift-length ProtoDUNE Dual Phase liquid argon TPC

DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6  ×  6  ×  6 m 3 liquid argon time-projection-chamber (LArTPC) that recorded cosmic-muon data at the CERN Neutrino Platform in 2019-2020 as a prototype of the DUNE Far Detector. Charged particles propagating through the LArTPC produce ionization and scintillation light. The scintillation light signal in these detectors can provide the trigger for non-beam events. In addition, it adds precise timing capabilities and improves the calorimetry measurements. In ProtoDUNE-DP, scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7 m away from the ionizing track. In this paper, the ProtoDUNE-DP photon detection system performance is evaluated with a particular focus on the different wavelength shifters, such as PEN and TPB, and the use of Xe-doped LAr, considering its future use in giant LArTPCs. The scintillation light production and propagation processes are analyzed and a comparison of simulation to data is performed, improving understanding of the liquid argon properties.

Alboserpin, the Main Salivary Anticoagulant from the Disease Vector Aedes albopictus, Displays Anti-FXa-PAR Signaling In Vitro and In Vivo

Blood-feeding arthropods secrete potent salivary molecules, which include platelet aggregation inhibitors, vasodilators, and anticoagulants. Among these molecules, Alboserpin, the major salivary anticoagulant from the mosquito vector Aedes albopictus, is a specific inhibitor of the human coagulation factor Xa (FXa). In this study, we investigated the anti-inflammatory properties of Alboserpin, in vitro and in vivo. In vitro, Alboserpin inhibited FXa-induced protease-activated receptor (PAR)-1, PAR-2, PAR-3, VCAM, ICAM, and NF-κB gene expression in primary dermal microvascular endothelial cells. Alboserpin also prevented FXa-stimulated ERK1/2 gene expression and subsequent inflammatory cytokine release (MCP-1, TNF-α, IL-6, IL-8, IL-1β, IL-18). In vivo, Alboserpin reduced paw edema induced by FXa and subsequent release of inflammatory cytokines (CCL2, MCP-1, IL-1α, IL-6, IL-1β). Alboserpin also reduced FXa-induced endothelial permeability in vitro and in vivo. These findings show that Alboserpin is a potent anti-inflammatory molecule, in vivo and in vitro, and may play a significant role in blood feeding.

Novel salivary antihemostatic activities of long-form D7 proteins from the malaria vector Anopheles gambiae facilitate hematophagy

To successfully feed on blood, hematophagous arthropods must combat the host's natural hemostatic and inflammatory responses. Salivary proteins of blood-feeding insects such as mosquitoes contain compounds that inhibit these common host defenses against blood loss, including vasoconstriction, platelet aggregation, blood clotting, pain, and itching. The D7 proteins are some of the most abundantly expressed proteins in female mosquito salivary glands and have been implicated in inhibiting host hemostatic and inflammatory responses. Anopheles gambiae, the primary vector of malaria, expresses three D7 long-form and five D7 short-form proteins. Previous studies have characterized the AngaD7 short-forms, but the D7 long-form proteins have not yet been characterized in detail. Here, we characterized the A. gambiae D7 long-forms by first determining their binding kinetics to hemostatic agonists such as leukotrienes and serotonin, which are potent activators of vasoconstriction, edema formation, and postcapillary venule leakage, followed by ex vivo functional assays. We found that AngaD7L1 binds leukotriene C4 and thromboxane A2 analog U-46619; AngaD7L2 weakly binds leukotrienes B4 and D4; and AngaD7L3 binds serotonin. Subsequent functional assays confirmed AngaD7L1 inhibits U-46619-induced platelet aggregation and vasoconstriction, and AngaD7L3 inhibits serotonin-induced platelet aggregation and vasoconstriction. It is therefore possible that AngaD7L proteins counteract host hemostasis by scavenging these mediators. Finally, we demonstrate that AngaD7L2 had a dose-dependent anticoagulant effect via the intrinsic coagulation pathway by interacting with factors XII, XIIa, and XI. The uncovering of these interactions in the present study will be essential for comprehensive understanding of the vector-host biochemical interface.

Aedes aegypti sialokinin facilitates mosquito blood feeding and modulates host immunity and vascular biology

Saliva from mosquitoes contains vasodilators that antagonize vasoconstrictors produced at the bite site. Sialokinin is a vasodilator present in the saliva of Aedes aegypti. Here, we investigate its function and describe its mechanism of action during blood feeding. Sialokinin induces nitric oxide release similar to substance P. Sialokinin-KO mosquitoes produce lower blood perfusion than parental mosquitoes at the bite site during probing and have significantly longer probing times, which result in lower blood feeding success. In contrast, there is no difference in feeding between KO and parental mosquitoes when using artificial membrane feeders or mice that are treated with a substance P receptor antagonist, confirming that sialokinin interferes with host hemostasis via NK1R signaling. While sialokinin-KO saliva does not affect virus infection in vitro, it stimulates macrophages and inhibits leukocyte recruitment in vivo. This work highlights the biological functionality of salivary proteins in blood feeding.

Xenotransplantation of porcine progenitor cells in an epileptic California sea lion (Zalophus californianus): illustrative case

BACKGROUND

Domoic acid (DA) is a naturally occurring neurotoxin harmful to marine animals and humans. California sea lions exposed to DA in prey during algal blooms along the Pacific coast exhibit significant neurological symptoms, including epilepsy with hippocampal atrophy.

OBSERVATIONS

Here the authors describe a xenotransplantation procedure to deliver interneuron progenitor cells into the damaged hippocampus of an epileptic sea lion with suspected DA toxicosis. The sea lion has had no evidence of seizures after the procedure, and clinical measures of well-being, including weight and feeding habits, have stabilized.

LESSONS

These preliminary results suggest xenotransplantation has improved the quality of life for this animal and holds tremendous therapeutic promise.

Multiple Salivary Proteins from Aedes aegypti Mosquito Bind to the Zika Virus Envelope Protein

Aedes aegypti mosquitoes are important vectors of several debilitating and deadly arthropod-borne (arbo) viruses, including Yellow Fever virus, Dengue virus, West Nile virus and Zika virus (ZIKV). Arbovirus transmission occurs when an infected mosquito probes the host’s skin in search of a blood meal. Salivary proteins from mosquitoes help to acquire blood and have also been shown to enhance pathogen transmission in vivo and in vitro. Here, we evaluated the interaction of mosquito salivary proteins with ZIKV by surface plasmon resonance and enzyme-linked immunosorbent assay. We found that three salivary proteins AAEL000793, AAEL007420, and AAEL006347 bind to the envelope protein of ZIKV with nanomolar affinities. Similar results were obtained using virus-like particles in binding assays. These interactions have no effect on viral replication in cultured endothelial cells and keratinocytes. Additionally, we found detectable antibody levels in ZIKV and DENV serum samples against the recombinant proteins that interact with ZIKV. These results highlight complex interactions between viruses, salivary proteins and antibodies that could be present during viral transmissions.

Aedes aegypti Piwi4 Structural Features Are Necessary for RNA Binding and Nuclear Localization

The PIWI-interacting RNA (piRNA) pathway provides an RNA interference (RNAi) mechanism known from Drosophila studies to maintain the integrity of the germline genome by silencing transposable elements (TE). Aedes aegypti mosquitoes, which are the key vectors of several arthropod-borne viruses, exhibit an expanded repertoire of Piwi proteins involved in the piRNA pathway, suggesting functional divergence. Here, we investigate RNA-binding dynamics and subcellular localization of A. aegypti Piwi4 (AePiwi4), a Piwi protein involved in antiviral immunity and embryonic development, to better understand its function. We found that AePiwi4 PAZ (Piwi/Argonaute/Zwille), the domain that binds the 3′ ends of piRNAs, bound to mature (3′ 2′ O-methylated) and unmethylated RNAs with similar micromolar affinities (K_D = 1.7 ± 0.8 μM and K_D of 5.0 ± 2.2 μM, respectively; p = 0.05) in a sequence independent manner. Through site-directed mutagenesis studies, we identified highly conserved residues involved in RNA binding and found that subtle changes in the amino acids flanking the binding pocket across PAZ proteins have significant impacts on binding behaviors, likely by impacting the protein secondary structure. We also analyzed AePiwi4 subcellular localization in mosquito tissues. We found that the protein is both cytoplasmic and nuclear, and we identified an AePiwi4 nuclear localization signal (NLS) in the N-terminal region of the protein. Taken together, these studies provide insights on the dynamic role of AePiwi4 in RNAi and pave the way for future studies aimed at understanding Piwi interactions with diverse RNA populations.