Privileged small molecules against neglected tropical diseases: A perspective from structure activity relationships

Neglected tropical diseases (NTDs) comprise diverse infections with more incidence in tropical/sub-tropical areas. In spite of preventive and therapeutic achievements, NTDs are yet serious threats to the public health. Epidemiological reports of world health organization (WHO) indicate that more than 1.5 billion people are afflicted with at least one NTD type. Among NTDs, leishmaniasis, chagas disease (CD) and human African trypanosomiasis (HAT) result in substantial morbidity and death, particularly within impoverished countries. The statistical facts call for robust efforts to manage the NTDs. Currently, most of the anti-NTD drugs are engaged with drug resistance, lack of efficient vaccines, limited spectrum of pharmacological effect and adverse reactions. To circumvent the issue, numerous scientific efforts have been directed to the synthesis and pharmacological development of chemical compounds as anti-infectious agents. A survey of the anti-NTD agents reveals that the majority of them possess privileged nitrogen, sulfur and oxygen-based heterocyclic structures. In this review, recent achievements in anti-infective small molecules against parasitic NTDs are described, particularly from the SAR (Structure activity relationship) perspective. We also explore current advocating strategies to extend the scope of anti-NTD agents.

Antileishmanial and Antitrypanosomes Drugs for the Current Century

Human infections by trypanosomatids are widely distributed and prevalent in the tropical and subtropical regions. Diseases caused by Trypanosoma and Leishmania have variable clinical outcomes, ranging from self-healing to fatality, and are considered Neglected Tropical Diseases (NTD). In addition, animal trypanosomiases have a significant impact on animal health and production, apart from their potential role as reservoirs in zoonotic species. Control of these infections is progressing and, in some cases (such as human African trypanomiasis (HAT)), significant reductions have been achieved. In the absence of effective vaccination, chemotherapy is the most used control method. Unfortunately, the therapeutic arsenal is scarce, old, and of variable efficacy, and reports of resistance to most antiparasitic agents have been published. New drugs, formulations, or combinations are needed to successfully limit the spread and severity of these diseases within a One Health framework. In this Special Issue, contributions regarding the identification and validation of drug targets, underlying mechanisms of action and resistance, and potential new molecules are presented. These research contributions are complemented by an update revision of the current chemotherapy against African Trypanosoma species, and a critical review of the shortcomings of the prevailing model of drug discovery and development.

Impact of basic psychological support on stigma and mental well-being of people with disabilities due to leprosy and lymphatic filariasis: a proof-of-concept study

BACKGROUND

People with leprosy and lymphatic filariasis (LF)-related disabilities experience higher levels of poor mental well-being compared with the general community. Mental health services are often not available. This study was conducted to provide proof of concept that basic psychological support for people affected by neglected tropical diseases (BPS-N) can be given by peer supporters to reduce stigma, improve mental well-being and participation among clients.

METHODS

The BPS-N approach was tested in a quasi-experimental design using mixed methods. To provide psychological support using the BPS-N, peer supporters were selected and trained. They supported people with leprosy- and LF-related disabilities. Preintervention and postintervention, stigma, mental well-being, depression and participation were measured through standard scales within 4 wk of the intervention; differences were tested using standard tests of significance.

RESULTS

After 3 mo of intervention, the mean level of stigma had decreased (30.3 to 24, p<0.001); high mental well-being increased (0% to 13.3%, p<0.001); and moderate to severe depression decreased (88% to 47%, p<0.001). No significant change occurred in participation restrictions (87% to 92%, p=0.497).

CONCLUSIONS

Psychological peer support using the BPS-N guideline appears effective in reducing stigma and improving mental well-being and can be operationalised. However, this should be confirmed through a randomised controlled trial.

CONTEXTE

Les personnes atteintes de lèpre et de handicaps liés à la filariose lymphatique (FL) souffrent davantage d'un manque de bien-être mental que le reste de la population. Les services de santé mentale ne sont souvent pas disponibles hors des zones urbaines. Cette étude a été menée pour démontrer que le soutien psychologique de base pour les personnes atteintes de MTN (BPS-N) peut être dispensé par des pairs (dans une logique de transfert de tâches) afin de réduire la stigmatisation et d'améliorer le bien-être mental et la participation des clients.

MÉTHODES

L'approche du BPS-N a été testée dans le cadre d'un modèle quasi-expérimental utilisant des méthodes mixtes. Pour fournir un soutien psychologique à l'aide du BPS-N, des pairs ont été sélectionnés et formés. Ils sont venus en aide aux personnes atteintes de lèpre et de déficiences liées à la FL. Avant et après l'intervention, les éléments suivants ont été mesurés à l'aide d'échelles standardisées: niveau de stigmatisation, bien-être mental, symptômes dépressifs, et enfin, la participation sociale. Les différences ont été testées à l'aide de tests de signification standardisés.

RÉSULTATS

Après 3 mois d'intervention, le niveau moyen de stigmatisation a diminué (30,3 à 24, p<0 001) ; le niveau de bien-être mental a augmenté (0% à 13,3%, p<0 001) et la dépression modérée à sévère a diminué (88% à 47%, p<0 001). Aucun changement significatif n'a été observé en ce qui concerne les restrictions de participation (87% contre 92%, p=0 497).

CONCLUSIONS

Le soutien psychologique par les pairs utilisant la ligne directrice BPS-N semble efficace pour réduire la stigmatisation et améliorer le bien-être mental. Toutefois, cette efficacité doit être confirmée par un essai contrôlé randomisé.

ANTECEDENTES

Las personas con lepra y discapacidades relacionadas con la filariasis linfática (FL) sufren niveles más altos de malestar mental en comparación con la comunidad en general. Los servicios de salud mental no suelen estar disponibles a nivel periférico. Este estudio se llevó a cabo para proporcionar una prueba de concepto de que el Apoyo Psicológico Básico para personas afectadas por NTDs (BPS-N) puede ser dado por compañeros de apoyo (rotación de tareas) para reducir el estigma, mejorar el bienestar mental y la participación entre los clientes.

MÉTODOS

El enfoque BPS-N se probó en un diseño cuasi-experimental utilizando métodos mixtos. Para proporcionar apoyo psicológico con el BPS-N, se seleccionaron y formaron compañeros de apoyo. Apoyaron a personas con lepra y discapacidades relacionadas con la FL. El estigma, el bienestar mental, la depresión y la participación se midieron antes y después de la intervención, mediante escalas estándar; las diferencias se comprobaron mediante pruebas estándar de significación.

RESULTADOS

Después de 3 meses de intervención, el nivel medio de estigma disminuyó (30,3 a 24, p<0 001); el bienestar mental alto aumentó (0% a 13,3%, p<0 001) y la depresión moderada a grave disminuyó (88% a 47%, p<0 001). No se produjeron cambios significativos en las restricciones de participación (87% frente a 92%, p=0 497)).

CONCLUSIONES

El apoyo psicológico entre iguales, utilizando la guía BPS-N, parece eficaz para reducir el estigma y mejorar el bienestar mental. Sin embargo, esto debe confirmarse mediante un ensayo controlado aleatorizado.

Developing low-cost house floors to control tungiasis in Kenya - a feasibility study

CONTEXT

Tungiasis is a neglected tropical skin disease endemic in resource-poor communities. It is caused by the penetration of the female sand flea, Tunga penetrans, into the skin causing immense pain, itching, difficulty walking, sleeping and concentrating on school or work. Infection is associated with living in a house with unsealed earthen house floors.

METHODS

This feasibility study used a community-based co-creation approach to develop and test simple, locally appropriate, and affordable flooring solutions to create a sealed, washable floor for the prevention of tungiasis. Locally used techniques were explored and compared in small slab trials. The floor with best strength and lowest cost was pilot trialed in 12 households with tungiasis cases to assess its durability and costs, feasibility of installation in existing local houses using local masons and explore community perceptions. Disease outcomes were measured to estimate potential impact.

RESULTS

It was feasible to build the capacity of a community-based organization to conduct research, develop a low-cost floor and conduct a pilot trial. The optimal low-cost floor was stabilized local subsoil with cement at a 1:9 ratio, installed as a 5 cm depth slab. A sealed floor was associated with a lower mean infection intensity among infected children than in control households (aIRR 0.53, 95%CI 0.29-0.97) when adjusted for covariates. The cost of the new floor was US$3/m2 compared to $10 for a concrete floor. Beneficiaries reported the floor made their lives much easier, enabled them to keep clean and children to do their schoolwork and eat while sitting on the floor. Challenges encountered indicate future studies would need intensive mentoring of masons to ensure the floor is properly installed and households supervised to ensure the floor is properly cured.

CONCLUSION

This study provided promising evidence that retrofitting simple cement-stabilised soil floors with locally available materials is a feasible option for tungiasis control and can be implemented through training of community-based organisations. Disease outcome data is promising and suggests that a definitive trial is warranted. Data generated will inform the design of a fully powered randomized trial combined with behaviour change communications.

TRIAL REGISTRATION

ISRCTN 62801024 (retrospective 07.07.2023).

Mechanistic and thermodynamic characterization of antiviral inhibitors targeting nucleocapsid N-terminal domain of SARS-CoV-2

The nucleocapsid (N) protein of SARS-CoV-2 plays a pivotal role in encapsulating the viral genome. Developing antiviral treatments for SARS-CoV-2 is imperative due to the diminishing immunity of the available vaccines. This study targets the RNA-binding site located in the N-terminal domain (NTD) of the N-protein to identify the potential antiviral molecules against SARS-CoV-2. A structure-based repurposing approach identified the twelve high-affinity molecules from FDA-approved drugs, natural products, and the LOPAC1280 compound libraries that precisely bind to the RNA binding site within the NTD. The interaction of these potential antiviral agents with the purified NTD protein was thermodynamically characterized using isothermal titration calorimetry (ITC). A fluorescence-based plate assay to assess the RNA binding inhibitory activity of small molecules against the NTD has been employed, and the selected compounds exhibited significant RNA binding inhibition with calculated IC50 values ranging from 8.8 μM to 15.7 μM. Furthermore, the antiviral efficacy of these compounds was evaluated using in vitro cell-based assays targeting the replication of SARS-CoV-2. Remarkably, two compounds, Telmisartan and BMS-189453, displayed potential antiviral activity against SARS-CoV-2, with EC50 values of approximately 1.02 μM and 0.98 μM, and a notable selective index of >98 and > 102, respectively. This study gives valuable insight into developing therapeutic interventions against SARS-CoV-2 by targeting the N-protein, a significant effort given the global public health concern posed due to the virus re-emergence and long COVID-19 disease.

Screening for Neglected Tropical Diseases and other infections in African refugees and asylum seekers in Rome and Lazio region, Italy

BACKGROUND

Few reliable data are available on Neglected Tropical Diseases (NTDs) and other infections among African refugees and asylum seekers in Italy. We aimed to estimate the prevalence of NTDs and other infections in a large cohort of African refugees and asylum seekers living in reception centers in Lazio, Italy.

MATERIAL AND METHODS

This is an observational, prospective prevalence study on infectious diseases in a large population of African refugees and asylum seekers (936 overall) consecutively enrolled for screening purpose at the Infectious and Tropical diseases outpatient clinic of the National Institute of Migrant and Poverty (INMP), Rome from August 2019 to December 2020.

RESULTS

We found a prevalence of 8.8 % and 31 % for Strongyloides and schistosoma infection, respectively, while the prevalence of human immunodeficiency virus (HIV) infection was 0.7 %, HCV antibodies 2.5%, hepatitis B virus surface antigen 10.8 % and syphilis serological tests 2.9 %.

CONCLUSION

Strongyloidiasis and schistosomiasis are highly prevalent among African refugees and asylum seekers in Italy, in contrast to communicable diseases (with the exception of hepatitis B). Raising awareness of NTDs among health professionals and implementing guidelines seems to be of paramount importance to prevent these diseases and their sufferers from becoming even more "neglected".

Global, regional, and national epidemiological trends in neural tube defects between 1990 and 2019: a summary

BACKGROUND

Neural tube defects (NTD), such as spina bifida, are surgically treatable and primarily preventable non-communicable diseases. How incidence, mortality and disability-adjusted life year (DALYs) rates of NTD have modulated over time is not well defined. Correspondingly, the aim of this study was to quantitively define the global, regional, and national epidemiological trends in these.

METHODS

A retrospective review of data from the Global Burden of Disease Study 2019 Database was performed. Global, regional, and national outcomes for NTD were collected for incidence, mortality, and DALY rates and their age-standardized metrics analyzed. There were 7 regions at a regional level, and 204 countries and territories at a national level.

RESULTS

Globally, the latest age-standardized rates of incidence, mortality, and DALYs of NTD were 2.1 per 100,000 population, 1.3 per 1000,000, and 117 per 100,000 respectively. All rates demonstrated decreases in the last two decades to now. Regionally, sub-Saharan Africa and North America demonstrated the highest and lowest age-standardized rates of incidence (4.0 vs 0.5 per 100,000), mortality (3.0 vs 0.4 per 100,000), and DALYs (266 vs 33 per 100,000), respectively. Similar to global trends, all regions demonstrated decrease in these rates over the last two decades. Nationally, the highest age-standardized rates were reported in African countries, Central African Republic, with highest incidence rate (7.6 per 100,000), and Burkina Faso with highest mortality rate (5.8 per 100,000) and DALY rate (518 per 100,000). India was the country with the highest number of new NTD cases (22,000 per country) in the most recent year of study. Between 1990 and 2019, 182/204 (89%), 188/204 (92%), and 188/204 (92%) countries and territories demonstrated a decrease in age-standardized incidence, mortality, and DALY rates respectively, with the greatest decreases seen in Saudi Arabia for all statistics.

CONCLUSIONS

Between 1990 and 2019, overall trends in incidence, mortality, and DALY rates of NTD have been favorably downtrending globally. Regionally, these rates in the highest sub-Saharan Africa were 8 times greater compared to the lowest North America. Nationally, although the majority of countries showed decreases in these rates, a small number of countries demonstrated uptrending rates of NTD. Understanding the mechanics behind these trends will allow future public health endeavors for both prevention and neurosurgical treatment to be targeted appropriately.

Modernizing the design and analysis of prevalence surveys for neglected tropical diseases

Current WHO guidelines set prevalence thresholds below which a neglected tropical disease can be considered to have been eliminated as a public health problem, and specify how surveys to assess whether elimination has been achieved should be designed and analysed, based on classical survey sampling methods. In this paper, we describe an alternative approach based on geospatial statistical modelling. We first show the gains in efficiency that can be obtained by exploiting any spatial correlation in the underlying prevalence. We then suggest that the current guidelines' implicit use of a significance testing argument is not appropriate; instead, we argue for a predictive inferential framework, leading to design criteria based on controlling the rates at which areas whose true prevalence lies above and below the elimination threshold are incorrectly classified. We describe how this approach naturally accommodates context-specific information in the form of georeferenced covariates that have been shown to be predictive of disease prevalence. Finally, we give a progress report of an ongoing collaboration with the Guyana Ministry of Health Neglected Tropical Disease programme on the design of an IDA (ivermectin, diethylcarbamazine and albendazole) Impact Survey of lymphatic filariasis to be conducted in Guyana in early 2023. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.

Tetrahydrobenzo[h]quinoline derivatives as a novel chemotype for dual antileishmanial-antimalarial activity graced with antitubercular activity: Design, synthesis and biological evaluation

Derivatives with tetrahydrobenzo[h]quinoline chemotype were synthesized via one-pot reactions and evaluated for their antileishmanial, antimalarial and antitubercular activities. Based on a structure-guided approach, they were designed to possess antileishmanial activity through antifolate mechanism, via targeting Leishmania major pteridine reductase 1 (Lm-PTR1). The in vitro antipromastigote and antiamastigote activity are promising for all candidates and superior to the reference miltefosine, in a low or sub micromolar range of activity. Their antifolate mechanism was confirmed via the ability of folic and folinic acids to reverse the antileishmanial activity of these compounds, comparably to Lm-PTR1 inhibitor trimethoprim. Molecular dynamics simulations confirmed a stable and high potential binding of the most active candidates against leishmanial PTR1. For the antimalarial activity, most of the compounds exhibited promising antiplasmodial effect against P. berghei with suppression percentage of up to 97.78%. The most active compounds were further screened in vitro against the chloroquine resistant strain P. falciparum, (RKL9) and showed IC50 value range of 0.0198-0.096 μM, compared to IC50 value of 0.19420 μM for chloroquine sulphate. Molecular docking of the most active compounds against the wild-type and quadruple mutant pf DHFR-TS structures rationalized the in vitro antimalarial activity. Some candidates showed good antitubercular activity against sensitive Mycobacterium tuberculosis in a low micromolar range of MIC, compared to 0.875 μM of isoniazid. The top active ones were further tested against a multidrug-resistant strain (MDR) and extensively drug-resistant strain (XDR) of Mycobacterium tuberculosis. Interestingly, the in vitro cytotoxicity test of the best candidates displayed high selectivity indices emphasizing their safety on mammalian cells. Generally, this work introduces a fruitful matrix for new dual acting antileishmanial-antimalarial chemotype graced with antitubercular activity. This would help in tackling drug-resistance issues in treating some Neglected Tropical Diseases.

Successful resection of delayed management rupture midline encephalocele: A case report

INTRODUCTION AND IMPORTANCE

Encephalocele is an NTD that affects one in every 10,000 live births. A ruptured encephalocele is advised to be operated on as soon as possible, preferably within 48 h. Signs and symptoms of infection should be considered when performing corrective surgery.

CASE PRESENTATION

We present the case of an 8-day-old baby who had a ruptured midline frontoparietal encephalocele as a result of delayed corrective surgery. The mass on the patient's head measured approximately 7 × 6 × 5 cm with a leakage of clear and yellowish fluids. The head CT scan revealed a multi-enhancement mass, pedunculated with an ill-defined border protruding from the anterior fontanelle.

CLINICAL DISCUSSION

The patient underwent an emergency corrective surgery. Excision was performed completely. The defect was covered with a double-layer closure technique in a watertight manner. The patient's postoperative recovery was uneventful.

CONCLUSION

An encephalocele can only be resolved through corrective surgery. In our case, the ruptured midline encephalocele was easily resolved with an emergency corrective surgery. Closure of the defect soon after birth is advised, especially if no layer of skin protects the encephalocele.

Examining the relationship between autism spectrum disorder and neural tube defects

Folate and vitamin B₁₂ deficiencies have been strongly associated with neural tube defects, preliminary research suggests folate and B₁₂ deficiency may also be associated with autism spectrum disorder (ASD). We examined the association between neural tube defects and ASD as a further avenue to examine the hypothesis that ASD is related to maternal folate and B₁₂ deficiency during pregnancy. A retrospective case-control study was performed using the Military Health System Data Repository. Cases and matched controls were followed from birth until at least 6 months after their first autism diagnosis. International Classification of Diseases, 9th Revision, codes were used to identify neural tube defects in the health records. A total of 8760 cases between the ages of 2 and 18 years were identified. The prevalence of any neural tube defect was 0.11% in children without ASD and 0.64% in children with ASD. Children with autism were over 6 times as likely to have a neural tube defect. The increased odds of neural tube defect in children diagnosed with ASD, found through our methodology, supports prior studies. Although additional studies are needed to elucidate the relationship between ASD and maternal folate and vitamin B₁₂ deficiency during pregnancy this study supports their use during pregnancy.

Structural insights into thermostable direct hemolysin of Vibrio parahaemolyticus using single-particle cryo-EM

Thermostable direct hemolysin (TDH) is a ~19 kDa, hemolytic pore-forming toxin from the gram-negative marine bacterium Vibrio parahaemolyticus, one of the causative agents of seafood-borne acute gastroenteritis and septicemia. Previous studies have established that TDH exists as a tetrameric assembly in physiological state; however, there is limited knowledge regarding the molecular arrangement of its disordered N-terminal region (NTR)-the absence of which has been shown to compromise TDH's hemolytic and cytotoxic abilities. In our current study, we have employed single-particle cryo-electron microscopy to resolve the solution-state structures of wild-type TDH and a TDH construct with deletion of the NTR (NTD), in order to investigate structural aspects of NTR on the overall tetrameric architecture. We observed that both TDH and NTD electron density maps, resolved at global resolutions of 4.5 and 4.2 Å, respectively, showed good correlation in their respective oligomeric architecture. Additionally, we were able to locate extra densities near the pore opening of TDH which might correspond to the disordered NTR. Surprisingly, under cryogenic conditions, we were also able to observe novel supramolecular assemblies of TDH tetramers, which we were able to resolve to 4.3 Å. We further investigated the tetrameric and inter-tetrameric interaction interfaces to elaborate upon the key residues involved in both TDH tetramers and TDH super assemblies. Our current structural study will aid in understanding the mechanistic aspects of this pore-forming toxin and the role of its disordered NTR in membrane interaction.

Drugs for neglected tropical diseases: availability of age-appropriate oral formulations for young children

It is recognised that paediatric indications and age-appropriate formulations are required to ensure that paediatric populations receive appropriate pharmacotherapeutic treatment. The lack of information on dosing, efficacy and safety data (labelling) is a well-recognised problem for all diseases affecting children. For neglected tropical diseases, the fact that they affect to a large extent poor and marginalised populations in low- and middle-income countries means that there is a low economic return on investment into paediatric development activities compared to other diseases [e.g. human immunodeficiency virus (HIV)]. This review provides an introduction to issues affecting the availability and development of paediatric population-relevant data and appropriate formulations of drugs for NTDs. We are summarising why age-appropriate formulations are important to ensure treatment efficacy, safety and effectiveness, outline initiatives to increase the number of paediatric indications/labelling and age-appropriate formulations, provide an overview of publicly available information on the formulations of oral drugs for NTDs relative to age appropriateness and give an introduction to options for age-appropriate formulations. The review completes with 'case studies' of recently developed paediatric formulations for NTDs, complemented by case studies for fixed-dose combinations for HIV infection in children since such formulations have not been developed for NTDs.

Importin α/β and the tug of war to keep TDP-43 in solution: quo vadis?

The transactivation response-DNA binding protein of 43 kDa (TDP-43) is an aggregation-prone nucleic acid-binding protein linked to the etiology of Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Lobar Degeneration (FTLD). These conditions feature the accumulation of insoluble TDP-43 aggregates in the neuronal cytoplasm that lead to cell death. The dynamics between cytoplasmic and nuclear TDP-43 are altered in the disease state where TDP-43 mislocalizes to the cytoplasm, disrupting Nuclear Pore Complexes (NPCs), and ultimately forming large fibrils stabilized by the C-terminal prion-like domain. Here, we review three emerging and poorly understood aspects of TDP-43 biology linked to its aggregation. First, how post-translational modifications in the proximity of TDP-43 N-terminal domain (NTD) promote aggregation. Second, how TDP-43 engages FG-nucleoporins in the NPC, disrupting the pore permeability and function. Third, how the importin α/β heterodimer prevents TDP-43 aggregation, serving both as a nuclear import transporter and a cytoplasmic chaperone.

Evolutionary remodelling of N-terminal domain loops fine-tunes SARS-CoV-2 spike

The emergence of SARS-CoV-2 variants has exacerbated the COVID-19 global health crisis. Thus far, all variants carry mutations in the spike glycoprotein, which is a critical determinant of viral transmission being responsible for attachment, receptor engagement and membrane fusion, and an important target of immunity. Variants frequently bear truncations of flexible loops in the N-terminal domain (NTD) of spike; the functional importance of these modifications has remained poorly characterised. We demonstrate that NTD deletions are important for efficient entry by the Alpha and Omicron variants and that this correlates with spike stability. Phylogenetic analysis reveals extensive NTD loop length polymorphisms across the sarbecoviruses, setting an evolutionary precedent for loop remodelling. Guided by these analyses, we demonstrate that variations in NTD loop length, alone, are sufficient to modulate virus entry. We propose that variations in NTD loop length act to fine-tune spike; this may provide a mechanism for SARS-CoV-2 to navigate a complex selection landscape encompassing optimisation of essential functionality, immune-driven antigenic variation and ongoing adaptation to a new host.

Receptor-Binding Domain (RBD) Antibodies Contribute More to SARS-CoV-2 Neutralization When Target Cells Express High Levels of ACE2

Neutralization assays are experimental surrogates for the effectiveness of infection- or vaccine-elicited polyclonal antibodies and therapeutic monoclonal antibodies targeting SARS-CoV-2. However, the measured neutralization can depend on the details of the experimental assay. Here, we systematically assess how ACE2 expression in target cells affects neutralization by antibodies to different spike epitopes in lentivirus pseudovirus neutralization assays. For high ACE2-expressing target cells, receptor-binding domain (RBD) antibodies account for nearly all neutralizing activity in polyclonal human sera. However, for lower ACE2-expressing target cells, antibodies targeting regions outside the RBD make a larger (although still modest) contribution to serum neutralization. These serum-level results are mirrored for monoclonal antibodies: N-terminal domain (NTD) antibodies and RBD antibodies that do not compete for ACE2 binding incompletely neutralize on high ACE2-expressing target cells, but completely neutralize on cells with lower ACE2 expression. Our results show that the ACE2 expression level in the target cells is an important experimental variable, and that high ACE2 expression emphasizes the role of a subset of RBD-directed antibodies.

SARS-CoV-2 spike N-terminal domain modulates TMPRSS2-dependent viral entry and fusogenicity

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike N-terminal domain (NTD) remains poorly characterized despite enrichment of mutations in this region across variants of concern (VOCs). Here, we examine the contribution of the NTD to infection and cell-cell fusion by constructing chimeric spikes bearing B.1.617 lineage (Delta and Kappa variants) NTDs and generating spike pseudotyped lentivirus. We find that the Delta NTD on a Kappa or wild-type (WT) background increases S1/S2 cleavage efficiency and virus entry, specifically in lung cells and airway organoids, through use of TMPRSS2. Delta exhibits increased cell-cell fusogenicity that could be conferred to WT and Kappa spikes by Delta NTD transfer. However, chimeras of Omicron BA.1 and BA.2 spikes with a Delta NTD do not show more efficient TMPRSS2 use or fusogenicity. We conclude that the NTD allosterically modulates S1/S2 cleavage and spike-mediated functions in a spike context-dependent manner, and allosteric interactions may be lost when combining regions from more distantly related VOCs.

Characterization of SARS-CoV-2 Escape Mutants to a Pair of Neutralizing Antibodies Targeting the RBD and the NTD

Mutations in the spike protein of SARS-CoV-2 can lead to evasion from neutralizing antibodies and affect the efficacy of passive and active immunization strategies. Immunization of mice harboring an entire set of human immunoglobulin variable region gene segments allowed to identify nine neutralizing monoclonal antibodies, which either belong to a cluster of clonally related RBD or NTD binding antibodies. To better understand the genetic barrier to emergence of SARS-CoV-2 variants resistant to these antibodies, escape mutants were selected in cell culture to one antibody from each cluster and a combination of the two antibodies. Three independently derived escape mutants to the RBD antibody harbored mutations in the RBD at the position T478 or S477. These mutations impaired the binding of the RBD antibodies to the spike protein and conferred resistance in a pseudotype neutralization assay. Although the binding of the NTD cluster antibodies were not affected by the RBD mutations, the RBD mutations also reduced the neutralization efficacy of the NTD cluster antibodies. The mutations found in the escape variants to the NTD antibody conferred resistance to the NTD, but not to the RBD cluster antibodies. A variant resistant to both antibodies was more difficult to select and only emerged after longer passages and higher inoculation volumes. VOC carrying the same mutations as the ones identified in the escape variants were also resistant to neutralization. This study further underlines the rapid emergence of escape mutants to neutralizing monoclonal antibodies in cell culture and indicates the need for thorough investigation of escape mutations to select the most potent combination of monoclonal antibodies for clinical use.

Religion and gender behavior: understanding the variations in risk to urinary schistosomiasis among farmers

Urinary schistosomiasis is a chronic and acute disease that is widely spread among the poor. It is caused by blood fluke of the genus Schistosoma, and transmitted to humans through water related activities by way of skin penetration. While schistosomiasis is rarely fatal, it could impact negatively on the economy and health status of infected individual. We evaluated the prevalence and dissimilarity of schistosomiasis among farmers in a cross sectional study, while grouping the farmers into different categories. Prior to the initiation of the study, we sought permission from the community head (Emir) and properly enlightened the community about the study. Then, we collected and analyzed urine samples from the consenting farmers using sedimentation techniques. The infection rate among participants was 46.3% (56/121), although with varying prevalence across different farming categories. We found no statistical difference among Muslim and Christian farmers even though there was higher infection rate (50.7%) among the Muslim than Christian (40%). Conversely, when classifying farming type by gender, male farmers, especially the male vegetable farmers were significantly different from female farmers of other farming types, while there was no statistical difference in the classification of farming type by religion. Although we found no statistical difference in the primary demographic factors of the participants, however the significant difference recorded in some of the combination of the participants' demographic factors shows that religion and gender might be an underlining factors that are responsible for the prevalence of the infection among the study participants. Therefore, this study will guide the decision makers in appropriately allocating future interventions among the endemic groups.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12639-021-01448-0.

Neutralizing antibody 5-7 defines a distinct site of vulnerability in SARS-CoV-2 spike N-terminal domain

Antibodies that potently neutralize SARS-CoV-2 target mainly the receptor-binding domain or the N-terminal domain (NTD). Over a dozen potently neutralizing NTD-directed antibodies have been studied structurally, and all target a single antigenic supersite in NTD (site 1). Here, we report the cryo-EM structure of a potent NTD-directed neutralizing antibody 5-7, which recognizes a site distinct from other potently neutralizing antibodies, inserting a binding loop into an exposed hydrophobic pocket between the two sheets of the NTD β sandwich. Interestingly, this pocket was previously identified as the binding site for hydrophobic molecules, including heme metabolites, but we observe that their presence does not substantially impede 5-7 recognition. Mirroring its distinctive binding, antibody 5-7 retains neutralization potency with many variants of concern (VOCs). Overall, we reveal that a hydrophobic pocket in NTD proposed for immune evasion can be used by the immune system for recognition.

A Combination of Receptor-Binding Domain and N-Terminal Domain Neutralizing Antibodies Limits the Generation of SARS-CoV-2 Spike Neutralization-Escape Mutants

Most known SARS-CoV-2 neutralizing antibodies (nAbs), including those approved by the FDA for emergency use, inhibit viral infection by targeting the receptor-binding domain (RBD) of the spike (S) protein. Variants of concern (VOC) carrying mutations in the RBD or other regions of S reduce the effectiveness of many nAbs and vaccines by evading neutralization. Therefore, therapies that are less susceptible to resistance are urgently needed. Here, we characterized the memory B-cell repertoire of COVID-19 convalescent donors and analyzed their RBD and non-RBD nAbs. We found that many of the non-RBD-targeting nAbs were specific to the N-terminal domain (NTD). Using neutralization assays with authentic SARS-CoV-2 and a recombinant vesicular stomatitis virus carrying SARS-CoV-2 S protein (rVSV-SARS2), we defined a panel of potent RBD and NTD nAbs. Next, we used a combination of neutralization-escape rVSV-SARS2 mutants and a yeast display library of RBD mutants to map their epitopes. The most potent RBD nAb competed with hACE2 binding and targeted an epitope that includes residue F490. The most potent NTD nAb epitope included Y145, K150, and W152. As seen with some of the natural VOC, the neutralization potencies of COVID-19 convalescent-phase sera were reduced by 4- to 16-fold against rVSV-SARS2 bearing Y145D, K150E, or W152R spike mutations. Moreover, we found that combining RBD and NTD nAbs did not enhance their neutralization potential. Notably, the same combination of RBD and NTD nAbs limited the development of neutralization-escape mutants in vitro, suggesting such a strategy may have higher efficacy and utility for mitigating the emergence of VOC. IMPORTANCE The U.S. FDA has issued emergency use authorizations (EUAs) for multiple investigational monoclonal antibody (MAb) therapies for the treatment of mild to moderate COVID-19. These MAb therapeutics are solely targeting the receptor-binding domain of the SARS-CoV-2 spike protein. However, the N-terminal domain of the spike protein also carries crucial neutralizing epitopes. Here, we show that key mutations in the N-terminal domain can reduce the neutralizing capacity of convalescent-phase COVID-19 sera. We report that a combination of two neutralizing antibodies targeting the receptor-binding and N-terminal domains may be beneficial to combat the emergence of virus variants.

Prevalence and molecular characteristics of feline coronavirus in southwest China from 2017 to 2020

Feline coronavirus (FCoV) is the causative agent of feline infectious peritonitis and diarrhoea in kittens worldwide. In this study, a total of 173 feline diarrhoeal faecal and ascetic samples were collected from 15 catteries and six veterinary hospitals in southwest China from 2017 to 2020. FCoV was detected in 80.35 % (139/173) of the samples using the RT-nPCR method; these included infections with 122 type I FCoV and 57 type II FCoV. Interestingly, 51 cases had co-infection with types I and II, the first such report in mainland China. To further analyse the genetic diversity of FCoV, we amplified 23 full-length spike (S) genes, including 18 type I and five type II FCoV. The type I FCoV and type II FCoV strains shared 85.5-98.7% and 97.4-98.9% nucleotide (nt) sequence identities between one another, respectively. The N-terminal domain (NTD) of 23 FCoV strains showed a high degree of variation (73.6-80.3 %). There was six type I FCoV strains with two amino acid insertions (159HL160) in the NTD. In addition, 18 strains of type I FCoV belonged to the Ie cluster, and five strains of type II FCoV were in the IIb cluster based on phylogenetic analysis. Notably, it was first time that two type I FCoV strains had recombination in the NTD, and the recombination regions was located 140-857 nt of the S gene. This study constitutes a systematic investigation of the current infection status and molecular characteristics of FCoV in southwest China.

Homologous and heterologous serological response to the N-terminal domain of SARS-CoV-2 in humans and mice

The increasing numbers of infected cases of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses serious threats to public health and the global economy. Most SARS-CoV-2 neutralizing antibodies target the receptor binding domain (RBD) and some the N-terminal domain (NTD) of the spike protein, which is the major antigen of SARS-CoV-2. While the antibody response to RBD has been extensively characterized, the antigenicity and immunogenicity of the NTD protein are less well studied. Using 227 plasma samples from COVID-19 patients, we showed that SARS-CoV-2 NTD-specific antibodies could be induced during infection. As compared to the results of SARS-CoV-2 RBD, the serological response of SARS-CoV-2 NTD is less cross-reactive with SARS-CoV, a pandemic strain that was identified in 2003. Furthermore, neutralizing antibodies are rarely elicited in a mice model when NTD is used as an immunogen. We subsequently demonstrate that NTD has an altered antigenicity when expressed alone. Overall, our results suggest that while NTD offers a supplementary strategy for serology testing, it may not be suitable as an immunogen for vaccine development.

Arnold-Chiari Malformation: Core Concepts

Arnold-Chiari malformation (ACM), a defect that involves downward displacement of the hindbrain and herniation of the cerebellar vermis, tonsils, pons, medulla, and fourth ventricle through the foramen magnum, is the most complex of the 4 types of Chiari malformations. Unique to the other types of Chiari malformations, approximately 95 percent of infants with ACM also present with an associated myelomeningocele (MMC), the most severe form of spina bifida. Among affected infants, those with symptomatic comorbidities incur a significantly higher morbidity and mortality risk. Prompt identification and diagnosis of ACM, as well as evidence-based postnatal and postsurgical nursing and medical care, is critical. Early surgical intervention can repair an existing MMC and restore proper cerebrospinal fluid circulation, which can dramatically improve patient outcomes and quality of life, and reduce disease and health care burden.

SARS-CoV-2 mRNA vaccination induces functionally diverse antibodies to NTD, RBD, and S2

In this study we profiled vaccine-induced polyclonal antibodies as well as plasmablast-derived mAbs from individuals who received SARS-CoV-2 spike mRNA vaccine. Polyclonal antibody responses in vaccinees were robust and comparable to or exceeded those seen after natural infection. However, the ratio of binding to neutralizing antibodies after vaccination was greater than that after natural infection and, at the monoclonal level, we found that the majority of vaccine-induced antibodies did not have neutralizing activity. We also found a co-dominance of mAbs targeting the NTD and RBD of SARS-CoV-2 spike and an original antigenic-sin like backboost to spikes of seasonal human coronaviruses OC43 and HKU1. Neutralizing activity of NTD mAbs but not RBD mAbs against a clinical viral isolate carrying E484K as well as extensive changes in the NTD was abolished, suggesting that a proportion of vaccine-induced RBD binding antibodies may provide substantial protection against viral variants carrying single E484K RBD mutations.

Isolation and characterization of cross-neutralizing coronavirus antibodies from COVID-19+ subjects

SARS-CoV-2 is one of three coronaviruses that have crossed the animal-to-human barrier and caused widespread disease in the past two decades. The development of a universal human coronavirus vaccine could prevent future pandemics. We characterize 198 antibodies isolated from four COVID-19+ subjects and identify 14 SARS-CoV-2 neutralizing antibodies. One targets the N-terminal domain (NTD), one recognizes an epitope in S2, and 11 bind the receptor-binding domain (RBD). Three anti-RBD neutralizing antibodies cross-neutralize SARS-CoV-1 by effectively blocking binding of both the SARS-CoV-1 and SARS-CoV-2 RBDs to the ACE2 receptor. Using the K18-hACE transgenic mouse model, we demonstrate that the neutralization potency and antibody epitope specificity regulates the in vivo protective potential of anti-SARS-CoV-2 antibodies. All four cross-neutralizing antibodies neutralize the B.1.351 mutant strain. Thus, our study reveals that epitopes in S2 can serve as blueprints for the design of immunogens capable of eliciting cross-neutralizing coronavirus antibodies.

Mycetoma: the journey from neglect to recognition as a neglected tropical disease

Mycetoma recently had gained international attention and conscious awareness after its inclusion under the WHO/NTD list in 2016. The journey to achieve that was both long, challenging as well as it was exciting and hard. In this article, the milestones and various events that took place in this journey were documented and highlighted.

STAT1 N-terminal domain discriminatively controls type I and type II IFN signaling

The seven signal transducers of transcription (STATs) are cytokine-inducible modular transcription factors. They transmit the stimulation of cells with type I interferons (IFN-α/IFN-β) and type II interferon (IFN-ɣ) into altered gene expression patterns. The N-terminal domain (NTD) of STAT1 is a surface for STAT1/STAT1 homodimer and STAT1/STAT2 heterodimer formation and allows the cooperative DNA binding of STAT1. We investigated whether the STAT1 NTD-mediated dimerization affected the IFN-induced tyrosine phosphorylation of STAT1, its nuclear translocation, STAT1-dependent gene expression, and IFN-dependent antiviral defense. We reconstituted human STAT1-negative and STAT2-negative fibrosarcoma cells with STAT1, NTD-mutated STAT1 (STAT1AA), STAT1 with a mutated DNA-binding domain (DBD), or STAT2. We treated these cells with IFN-α and IFN-ɣ to assess differences between IFN-α-induced STAT1 homo- and heterodimers and IFN-ɣ-induced STAT1 homodimers. Our data demonstrate that IFNs induce the phosphorylation of STAT1 and STAT1AA at Y701 and their nuclear accumulation. We further reveal that STAT1AA can be phosphorylated in response to IFN-α in the absence of STAT2 and that IFN-ɣ-induced STAT1AA can activate gene expression directly. However, STAT1AA largely fails to bind STAT2 and to activate IFN-α-induced expression of endogenous antiviral STAT1/STAT2 target proteins. Congruent herewith, both an intact STAT1 NTD and STAT2 are indispensable to establish an antiviral state with IFN-α. These data provide new insights into the biological importance of the STAT1 NTD.

Increased resistance of SARS-CoV-2 variant P.1 to antibody neutralization

The emergence of SARS-CoV-2 variants has raised concerns about altered sensitivity to antibody-mediated immunity. The relative resistance of SARS-CoV-2 variants B.1.1.7 and B.1.351 to antibody neutralization has been recently investigated. We report that another emergent variant from Brazil, P.1, is not only refractory to multiple neutralizing monoclonal antibodies but also more resistant to neutralization by convalescent plasma and vaccinee sera. The magnitude of resistance is greater for monoclonal antibodies than vaccinee sera and evident with both pseudovirus and authentic P.1 virus. The cryoelectron microscopy structure of a soluble prefusion-stabilized spike reveals that the P.1 trimer adopts exclusively a conformation in which one of the receptor-binding domains is in the "up" position, which is known to facilitate binding to entry receptor ACE2. The functional impact of P.1 mutations thus appears to arise from local changes instead of global conformational alterations. The P.1 variant threatens current antibody therapies but less so protective vaccine efficacy.

N-terminal domain antigenic mapping reveals a site of vulnerability for SARS-CoV-2

The SARS-CoV-2 spike (S) glycoprotein contains an immunodominant receptor-binding domain (RBD) targeted by most neutralizing antibodies (Abs) in COVID-19 patient plasma. Little is known about neutralizing Abs binding to epitopes outside the RBD and their contribution to protection. Here, we describe 41 human monoclonal Abs (mAbs) derived from memory B cells, which recognize the SARS-CoV-2 S N-terminal domain (NTD) and show that a subset of them neutralize SARS-CoV-2 ultrapotently. We define an antigenic map of the SARS-CoV-2 NTD and identify a supersite (designated site i) recognized by all known NTD-specific neutralizing mAbs. These mAbs inhibit cell-to-cell fusion, activate effector functions, and protect Syrian hamsters from SARS-CoV-2 challenge, albeit selecting escape mutants in some animals. Indeed, several SARS-CoV-2 variants, including the B.1.1.7, B.1.351, and P.1 lineages, harbor frequent mutations within the NTD supersite, suggesting ongoing selective pressure and the importance of NTD-specific neutralizing mAbs for protective immunity and vaccine design.

How modelling can help steer the course set by the World Health Organization 2021-2030 roadmap on neglected tropical diseases

The World Health Organization recently launched its 2021-2030 roadmap, Ending the Neglect to Attain the Sustainable Development Goals , an updated call to arms to end the suffering caused by neglected tropical diseases. Modelling and quantitative analyses played a significant role in forming these latest goals. In this collection, we discuss the insights, the resulting recommendations and identified challenges of public health modelling for 13 of the target diseases: Chagas disease, dengue, gambiense human African trypanosomiasis (gHAT), lymphatic filariasis (LF), onchocerciasis, rabies, scabies, schistosomiasis, soil-transmitted helminthiases (STH), Taenia solium taeniasis/ cysticercosis, trachoma, visceral leishmaniasis (VL) and yaws. This piece reflects the three cross-cutting themes identified across the collection, regarding the contribution that modelling can make to timelines, programme design, drug development and clinical trials.

How modelling can help steer the course set by the World Health Organization 2021-2030 roadmap on neglected tropical diseases

The World Health Organization recently launched its 2021-2030 roadmap, Ending the Neglect to Attain the Sustainable Development Goals , an updated call to arms to end the suffering caused by neglected tropical diseases. Modelling and quantitative analyses played a significant role in forming these latest goals. In this collection, we discuss the insights, the resulting recommendations and identified challenges of public health modelling for 13 of the target diseases: Chagas disease, dengue, gambiense human African trypanosomiasis (gHAT), lymphatic filariasis (LF), onchocerciasis, rabies, scabies, schistosomiasis, soil-transmitted helminthiases (STH), Taenia solium taeniasis/ cysticercosis, trachoma, visceral leishmaniasis (VL) and yaws. This piece reflects the three cross-cutting themes identified across the collection, regarding the contribution that modelling can make to timelines, programme design, drug development and clinical trials.

Severely stigmatised skin neglected tropical diseases: a protocol for social science engagement

More than one billion people are affected by neglected tropical diseases (NTDs) and many of these diseases are preventable. While the grouping of these conditions as NTDs has generated vast mapping, mass drug administration and surveillance programmes, there is growing evidence of gaps and weaknesses in purely biomedical approaches, and the need for responses that also recognise the social determinants of health. In order to unpack the social and political determinants of NTDs, it is important to view the problem from a social science perspective. Given this background, the Social Sciences for Severe Stigmatizing Skin Diseases (5S) Foundation has recently been established by the Centre for Global Health Research at Brighton and Sussex Medical School. The broad aim of the 5S Foundation is to incorporate social science perspectives in understanding and addressing the problems around three NTDs, namely, podoconiosis, mycetoma and scabies. This protocol paper sets out the aims and approaches of the 5S Foundation while activities such as research, public engagement, training and capacity building get underway.

Japan's innovation for global health - GHIT's catalytic role

The global fight against infectious diseases, both emerging and re-emerging, endures. Japan's commitments and reputation as a good global citizen and its responsibility to uphold domestic and international human security mean that it is in Japan's best interest to leverage its innovative and technological capabilities for global infectious disease prevention and control. The Global Health Innovative Technology Fund (GHIT Fund), an international non-profit organization based in Tokyo, Japan, was established by the Japanese government, multiple Japanese pharmaceutical companies, and the Bill & Melinda Gates Foundation as the first fund of its kind, with an aim to tackle the global burden of infectious diseases by facilitating and funding global health R&D of drugs, vaccines, and diagnostics. Since its inception in 2013, the GHIT Fund has invested more than 209 million USD in more than 90 projects, which consist of collaborations among Japanese and non-Japanese entities, six of which have already progressed to clinical stage development. Japan will continue to play a major role in the global health arena by further advancing R&D innovations for infectious diseases.

LmjF.22.0810 from Leishmania major Modulates the Th2-Type Immune Response and Is Involved in Leishmaniasis Outcome

A novel serine/threonine protein kinase, LmjF.22.0810, was recently described in Leishmania major. After generating an L. major cell line overexpressing LmjF.22.0810 (named LmJ3OE), the ability of this novel protein to modulate the Th2-type immune response was analyzed. Our results suggest that the protein kinase LmjF.22.0810 might be involved in leishmaniasis outcomes. Indeed, our study outlined the LmJ3OE parasites infectivity in vitro and in vivo. Transgenic parasites displayed lower phagocytosis rates in vitro, and their promastigote forms exhibited lower expression levels of virulence factors compared to their counterparts in control parasites. In addition, LmJ3OE parasites developed significantly smaller footpad swelling in susceptible BALB/c mice. Hematoxylin-eosin staining allowed the observation of a lower inflammatory infiltrate in the footpad from LmJ3OE-infected mice compared to animals inoculated with control parasites. Gene expression of Th2-associated cytokines and effectors revealed a dramatically lower induction in interleukin (IL)-4, IL-10, and arginase 1 (ARG1) mRNA levels at the beginning of the swelling; no expression change was found in Th1-associated cytokines except for IL-12. Accordingly, such results were validated by immunohistochemistry studies, illustrating a weaker expression of ARG1 and a similar induction for inducible NO synthase (iNOS) in footpads from LmJ3OE-infected mice compared to control L. major infected animals. Furthermore, the parasite burden was lower in footpads from LmJ3OE-infected mice. Our analysis indicated that such significant smaller footpad swellings might be due to an impairment of the Th2 immune response that subsequently benefits Th1 prevalence. Altogether, these studies depict LmjF.22.0810 as a potential modulator of host immune responses to Leishmania. Finally, this promising target might be involved in the modulation of infection outcome.

Poor WASH (Water, Sanitation, and Hygiene) Conditions Are Associated with Leprosy in North Gondar, Ethiopia

Access to safe water, sanitation, and hygiene (WASH) is critical for preventing the spread of neglected tropical diseases (NTDs) including leprosy. WASH-related transmission factors remain largely unexplored in the leprosy transmission cycle. The aim of this project is to better understand WASH exposures among leprosy cases through a case-control study in North Gondar, Ethiopia. We hypothesized that leprosy cases were more likely to have inadequate WASH access and were more likely to have concurrent schistosomiasis, as schistosomiasis immune consequences may facilitate leprosy infection. Forty leprosy cases (forty-one controls) were enrolled, tested for Schistosomamansoni, administered a demographic and WASH survey, and assigned a WASH index score. WASH factors significantly associated with leprosy on adjusted analyses included open defecation (aOR = 19.9, 95% CI 2.2, 176.3) and lack of access to soap (aOR = 7.3, 95% CI 1.1, 49.9). S. mansoni was detected in 26% of participants and in stratified analysis those with leprosy had a 3.6 (95% CI (0.8, 15.9)) greater odds of schistosomiasis in districts bordering the lake, compared to 0.33 lower odds of schistosomiasis in districts not bordering the lake (95% CI (0.09, 1.2)). Overall, results suggest that leprosy transmission may be related to WASH adequacy and access as well as to schistosomiasis co-infection.

Neural defects caused by total and Wnt1-Cre mediated ablation of p120ctn in mice

Background

p120 catenin (p120ctn) is an important component in the cadherin-catenin cell adhesion complex because it stabilizes cadherin-mediated intercellular junctions. Outside these junctions, p120ctn is actively involved in the regulation of small GTPases of the Rho family, in actomyosin dynamics and in transcription regulation. We and others reported that loss of p120ctn in mouse embryos results in an embryonic lethal phenotype, but the exact developmental role of p120ctn during brain formation has not been reported.

Results

We combined floxed p120ctn mice with Del-Cre or Wnt1-Cre mice to deplete p120ctn from either all cells or specific brain and neural crest cells. Complete loss of p120ctn in mid-gestation embryos resulted in an aberrant morphology, including growth retardation, failure to switch from lordotic to fetal posture, and defective neural tube formation and neurogenesis. By expressing a wild-type p120ctn from the ROSA26 locus in p120ctn-null mouse embryonic stem cells, we could partially rescue neurogenesis. To further investigate the developmental role of p120ctn in neural tube formation, we generated conditional p120ctn^fl/fl;Wnt1Cre knockout mice. p120ctn deletion in Wnt1-expressing cells resulted in neural tube closure defects (NTDs) and craniofacial abnormalities. These defects could not be correlated with misregulation of brain marker genes or cell proliferation. In contrast, we found that p120ctn is required for proper expression of the cell adhesion components N-cadherin, E-cadherin and β-catenin, and of actin-binding proteins cortactin and Shroom3 at the apical side of neural folds. This region is of critical importance for closure of neural folds. Surprisingly, the lateral side of mutant neural folds showed loss of p120ctn, but not of N-cadherin, β-catenin or cortactin.

Conclusions

These results indicate that p120ctn is required for neurogenesis and neurulation. Elimination of p120ctn in cells expressing Wnt1 affects neural tube closure by hampering correct formation of specific adhesion and actomyosin complexes at the apical side of neural folds. Collectively, our results demonstrate the crucial role of p120ctn during brain morphogenesis.

DVL mutations identified from human neural tube defects and Dandy-Walker malformation obstruct the Wnt signaling pathway

Wnt signaling pathways, including the canonical Wnt/β-catenin pathway, planar cell polarity pathway, and Wnt/Ca²⁺ signaling pathway, play important roles in neural development during embryonic stages. The DVL genes encode the hub proteins for Wnt signaling pathways. The mutations in DVL2 and DVL3 were identified from patients with neural tube defects (NTDs), but their functions in the pathogenesis of human neural diseases remain elusive. Here, we sequenced the coding regions of three DVL genes in 176 stillborn or miscarried fetuses with NTDs or Dandy-Walker malformation (DWM) and 480 adult controls from a Han Chinese population. Four rare mutations were identified: DVL1 p.R558H, DVL1 p.R606C, DVL2 p.R633W, and DVL3 p.R222Q. To assess the effect of these mutations on NTDs and DWM, various functional analyses such as luciferase reporter assay, stress fiber formation, and in vivo teratogenic assay were performed. The results showed that the DVL2 p.R633W mutation destabilized DVL2 protein and upregulated activities for all three Wnt signalings (Wnt/β-catenin signaling, Wnt/planar cell polarity signaling, and Wnt/Ca²⁺ signaling) in mammalian cells. In contrast, DVL1 mutants (DVL1 p.R558H and DVL1 p.R606C) decreased canonical Wnt/β-catenin signaling but increased the activity of Wnt/Ca²⁺ signaling, and DVL3 p.R222Q only decreased the activity of Wnt/Ca²⁺ signaling. We also found that only the DVL2 p.R633W mutant displayed more severe teratogenicity in zebrafish embryos than wild-type DVL2. Our study demonstrates that these four rare DVL mutations, especially DVL2 p.R633W, may contribute to human neural diseases such as NTDs and DWM by obstructing Wnt signaling pathways.

The Health and Economic Burdens of Lymphatic Filariasis Prior to Mass Drug Administration Programs

BACKGROUND

The Global Programme to Eliminate Lymphatic Filariasis (GPELF) was launched in 2000 with the goal of eliminating lymphatic filariasis (LF) as a public health problem by 2020. Despite considerable progress, the current prevalence is around 60% of the 2000 figure, with the deadline looming a year away. Consequently, there is a continued need for investment in both the mass drug administration (MDA) and morbidity management programs, and this paper aims to demonstrate that need by estimating the health and economic burdens of LF prior to MDA programs starting in GPELF areas.

METHODS

A previously developed model was used to estimate the numbers of individuals infected and individuals with symptomatic disease, along with the attributable number of disability-adjusted life years (DALYs). The economic burden was calculated by quantifying the costs incurred by the health-care system in managing clinical cases, the patients' out-of-pocket costs, and their productivity costs.

RESULTS

Prior to the MDA program, approximately 129 million people were infected with LF, of which 43 million had clinical disease, corresponding to a DALY burden of 5.25 million. The average annual economic burden per chronic case was US $115, the majority of which resulted from productivity costs. The total economic burden of LF was estimated at US $5.8 billion annually.

CONCLUSIONS

These results demonstrate the magnitude of the LF burden and highlight the continued need to support the GPELF. Patients with clinical disease bore the majority of the economic burden, but will not benefit much from the current MDA program, which is aimed at reducing transmission. This assessment further highlights the need to scale up morbidity management programs.

The Novel Serine/Threonine Protein Kinase LmjF.22.0810 from Leishmania major may be Involved in the Resistance to Drugs such as Paromomycin

The identification and clarification of the mechanisms of action of drugs used against leishmaniasis may improve their administration regimens and prevent the development of resistant strains. Herein, for the first time, we describe the structure of the putatively essential Ser/Thr kinase LmjF.22.0810 from Leishmania major. Molecular dynamics simulations were performed to assess the stability of the kinase model. The analysis of its sequence and structure revealed two druggable sites on the protein. Furthermore, in silico docking of small molecules showed that aminoglycosides preferentially bind to the phosphorylation site of the protein. Given that transgenic LmjF.22.0810-overexpressing parasites displayed less sensitivity to aminoglycosides such as paromomycin, our predicted models support the idea that the mechanism of drug resistance observed in those transgenic parasites is the tight binding of such compounds to LmjF.22.0810 associated with its overexpression. These results may be helpful to understand the complex machinery of drug response in Leishmania.

Nonstructural Protein 11 of Porcine Reproductive and Respiratory Syndrome Virus Induces STAT2 Degradation To Inhibit Interferon Signaling

Interferons (IFNs) play a crucial role in host antiviral response by activating the JAK/STAT (Janus kinase/signal transducer and activator of transcription) signaling pathway to induce the expression of myriad genes. STAT2 is a key player in the IFN-activated JAK/STAT signaling. Porcine reproductive and respiratory syndrome virus (PRRSV) is an important viral pathogen, causing huge losses to the swine industry. PRRSV infection elicits a meager protective immune response in pigs. The objective of this study was to investigate the effect of PRRSV on STAT2 signaling. Here, we demonstrated that PRRSV downregulated STAT2 to inhibit IFN-activated signaling. PRRSV strains of both PRRSV-1 and PRRSV-2 species reduced the STAT2 protein level, whereas the STAT2 transcript level had minimal change. PRRSV reduced the STAT2 level in a dose-dependent manner and shortened STAT2 half-life significantly from approximately 30 to 5 h. PRRSV-induced STAT2 degradation could be restored by treatment with the proteasome inhibitor MG132 and lactacystin. In addition, PRRSV nonstructural protein 11 (nsp11) was identified to interact with and reduce STAT2. The N-terminal domain (NTD) of nsp11 was responsible for STAT2 degradation and interacted with STAT2 NTD and the coiled-coil domain. Mutagenesis analysis showed that the amino acid residue K59 of nsp11 was indispensable for inducing STAT2 reduction. Mutant PRRSV with the K59A mutation generated by reverse genetics almost lost the ability to reduce STAT2. Together, these results demonstrate that PRRSV nsp11 antagonizes IFN signaling via mediating STAT2 degradation and provide further insights into the PRRSV interference of the innate immunity.IMPORTANCE PRRSV infection elicits a meager protective immune response in pigs. One of the possible reasons is that PRRSV antagonizes interferon induction and its downstream signaling. Interferons are key components in the innate immunity and play crucial roles against viral infection and in the activation of adaptive immune response via JAK/STAT signaling. STAT2 is indispensable in the JAK/STAT signaling since it is also involved in activation of antiviral activity in the absence of STAT1. Here, we discovered that PRRSV nsp11 downregulates STAT2. Interestingly, the N-terminal domain of nsp11 is responsible for inducing STAT2 degradation and directly interacts with STAT2 N-terminal domain. We also identified a crucial amino acid residue K59 in nsp11 since a mutation of it led to loss of the ability to downregulate STAT2. A mutant PRRSV with mutation of K59 had minimal effect on STAT2 reduction. Our data provide further insights into PRRSV interference with interferon signaling.

N-Terminal Domain Mediated Regulation of RORα1 Inhibits Invasive Growth in Prostate Cancer

Four members of the retinoic acid-related orphan receptor α (RORα) family (RORα1, RORα2, RORα3 and RORα4) are transcription factors that regulate several processes including circadian rhythm, lipid metabolism, cerebellar development, immune function, and cancer. Only two isoforms, RORα1 and 4, are specifically co-expressed in the murine and human. In the present study, we identified a specific N-terminal domain (NTD) of RORα1 that potentiated the downregulation of target genes involved in tumor progression and proliferation, based on results from RORα-deficient mouse embryonic fibroblasts and prostate carcinoma tissues. The hyperactivation of proliferative target genes were observed in RORα-deficient embryonic fibroblasts, and reconstitution of RORα1 inhibited this activation by a NTD dependent manner. Downregulation of RORα1 and upregulation of Wnt/β-catenin target genes were correlated in prostate cancer patients. These findings revealed the control of invasive growth by NTD-mediated RORα1 signaling, suggesting advanced approaches for the development of therapeutic drugs.

Structural and Electronic Origin of Bis-Lactam-Based High-Performance Organic Thin-Film Transistors

We describe herein the comprehensive theoretical and experimental studies on the transistor mobility of organic semiconductors by correlating a two-dimensional (2D) intermolecular interaction with thin-film morphology and the electronic coupling structure. We developed a novel bis-lactam-based small molecule, 1,5-dioctyl-3,7-di(thiophen-2-yl)-1,5-naphthyridine-2,6-dione (C8-NTDT), with a 2D-type C-H···O═C intermolecular interaction along the in-plane directions of the crystal packing structure, which is characteristically different from the one-dimensional-type intermolecular interaction shown in the typical bis-lactam molecule of 2,5-dioctyl-3,6-di(thiophen-2-yl)pyrrolo[3,4- c]pyrrole-1,4-dione (C8-DPPT). Experimentally and theoretically, C8-NTDT exhibited more favorable thin-film morphology and an electronic coupling structure for charge transport because of its unique 2D intermolecular interactions compared with C8-DPPT. In fact, C8-NTDT exhibited a hole mobility of up to 1.29 cm² V^-1 s^-1 and an on/off ratio of 10⁷ in a vacuum-processed device. Moreover, the high solubility with the 2D electronic coupling structure of C8-NTDT enables versatile solution processing for device fabrication without performance degradation compared to the vacuum-processed device. As an example, we could demonstrate a hole mobility of up to 1.10 cm² V^-1 s^-1 for the spin-coated devices, which is one of the best performances among the solution-processed organic field-effect transistors based on bis-lactam-containing small molecules.

Developmental Toxicity of Mycotoxin Fumonisin B₁ in Animal Embryogenesis: An Overview

A teratogenic agent or teratogen can disturb the development of an embryo or a fetus. Fumonisin B₁ (FB₁), produced by Fusarium verticillioides and F. proliferatum, is among the most commonly seen mycotoxins and contaminants from stale maize and other farm products. It may cause physical or functional defects in embryos or fetuses, if the pregnant animal is exposed to mycotoxin FB₁. Due to its high similarity in chemical structure with lipid sphinganine (Sa) and sphingosine (So), the primary component of sphingolipids, FB₁ plays a role in competitively inhibiting Sa and So, which are key enzymes in de novo ceramide synthase in the sphingolipid biosynthetic pathway. Therefore, it causes growth retardation and developmental abnormalities to the embryos of hamsters, rats, mice, and chickens. Moreover, maternal FB₁ toxicity can be passed onto the embryo or fetus, leading to mortality. FB₁ also disrupts folate metabolism via the high-affinity folate transporter that can then result in folate insufficiency. The deficiencies are closely linked to incidences of neural tube defects (NTDs) in mice or humans. The purpose of this review is to understand the toxicity and mechanisms of mycotoxin FB₁ on the development of embryos or fetuses.

The Inhibitory Effect of Some Drugs on Candida rugosa Lipase and Human Pancreatic Lipase: In vitro and In silico Studies

BACKGROUND AND OBJECTIVE

Side effects of some drugs may be useful in certain cases. In this work, we studied the inhibitory effects on Lipases of some medications as: Folic Acid which is taken by pregnant women, Colchicine and Febuxostat which is used as treatment of gout disease. These cases are linked to obesity, where women (BMI ≥ 30) have twice higher odds of having an NTDaffected pregnancy than the normal weight women, and the Gout disease frequently occurs in combination of a Metabolic syndrome. The risk of gout increases with the increase of the mass index. In silico studies were aimed to determine the mechanism of inhibition and different interactions for two enzymes: Candida rugosa lipase and human pancreatic lipase.

METHODS

In the first part of this study, we studied the inhibition activity of these medications on lipase activity of Candida rugosa in vitro. Autodock vina was used for molecular docking with 50 runs and 1000 obtained solutions. The saved interactions were with His449 and Ser209 for the three molecules.

RESULTS

The results show that these drugs have an important inhibition activity with IC50 values 0.64 mg/ml for Folic acid and 0.66 mg/ml for Febuxostat. The results of in silico show competitive, Noncompetitive and uncompetitive inhibition for folic acid, febuxostat and colchicine respectively for two enzymes with different repetition ratios of hydrogen bonds.

CONCLUSION

These observations support a higher intake of dietary folate, and febuxostat for losing weight to decrease NTD risk and prevent hyperuricemia and recurrent gout attacks.

Studying the C1772T polymorphism of Hif-1α and TGF-β3 IVS5+104 A/G polymorphism in children with congenital non-syndromic neural tube defects and their mothers

Prevalence of neural tube defect (NTD) has reduced after folic acid intake. However; which mechanisms are effective in NTD are not known exactly. In this study; due to the possible effects on hypoxic pathway and embryonic development, particularly on extracellular matrix components, Hif-1α Pro582Ser and TGF-β3 IVS5+104 A/G SfaN1 polymorphisms were studied by PCR-RFLP method both on children with NTDs and mothers. Statistical differences were seen for Hif-1α and TGF-β3 IVS5+104 A/G SfaN1 polymorphisms in children with NTDs but no difference was seen in mothers. Both genes are effective on many pathways and our results suggest that regulation of extracellular matrix components of children during fetal life is important in neural tube defects formation. The results of this study show that Hif-1α Pro582Ser and TGF-β3 IVS5+104 A/G SfaN1 polymorphisms may play a role in NTDs.

Anemia and growth retardation associated with Schistosoma haematobium infection in Mali: a possible subtle impact of a neglected tropical disease

Background

The aim of this cross-sectional study was to investigate a possible association of Schistosoma haematobium with child growth development and describe a plausible schistosomiasis-related anemia in children and adults in a highly schistosomiasis endemic area of Mali.

Methods

Urine, feces and blood samples from 399 participants of both sexes (2-40 years of age) were analyzed and supplemented by anthropometric measurements.

Results

S. haematobium prevalence was 79.8%, S. mansoni 13.2% and Plasmodium falciparum 80.2%. S. haematobium infection intensity as five categories was significantly associated with anemia; i.e., odds of having anemia in the highest and the next highest category was 3.25 (95% CL 1.61-6.55; p<0.01) and 2.45 (95% CL 1.28-4.70; p<0.01), respectively, of that in the three lower categories combined after adjusting for age group and gender and the interaction between the two factors. Anemia was most pronounced in the 2-5 year olds males (55.5%, n=98). P. falciparum infection was not significantly associated with anemia. Stunting (body mass index [BMI] for age z-score<-2.00) was observed in 2.6% (2/78) of the 2-5 years olds and in 7.7% (14/182) in the 6-19 years age group. Lower BMI-z-scores (as continuous variable) were associated with anemia (p<0.05) while high intensity of S. haematobium infection was not significant when adjusting for age group and anemia. Participants with malaria infection had lower z-scores (as continuous variables) of weight and height for age. Lower height for age z-scores were also associated with anemia.

Conclusions

S. haematobium infection is likely to impact on child growth and possibly also anemia in all age groups and advocates for inclusion of whole populations into future control programes.