Development and application of a novel method to characterize methylmercury exposure in newborns using dried blood spots.

BACKGROUND: Methylmercury (MeHg) is a pollutant of global concern. While there is a need to gauge early-life exposures, there remain outstanding ethical, financial, and practical challenges with using the preferred biomarker, whole blood, notably in pregnant women, infants, toddlers, and children. Dried bloodspots (DBS) may help overcome some of these challenges. Notably DBS are collected from newborns in many jurisdictions offering an institutionalized platform to efficiently characterize exposures. OBJECTIVE: To develop, validate, and apply a new method to measure MeHg levels in DBS with a specific aim to use this method to increase understanding of newborn exposures. METHODS: Method development and validation was pursued by consulting U.S. EPA Method 1630 and other resources. The method was applied to measure MeHg levels in DBS from newborns (n = 675) from the Michigan BioTrust for Health program. RESULTS: The assay's detection limit (0.3µg/L), accuracy (96-115% of expected), precision, linearity, and range met performance criteria guidelines. In the newborn DBS samples, the mean (SD) and geometric mean values of MeHg were 1.46 (0.90) and 1.25µg/L respectively, and ranged from 0.09 to 9.97µg/L. The values we report here are similar to cord blood mercury values reported elsewhere. CONCLUSIONS: This is the first characterization of MeHg exposure in newborns, and thus fills an important data gap as prior studies have focused on pregnant women, cord blood, or toddlers. This method helps overcome technical challenges associated with other proposed approaches, and moving ahead there is great promise for applying this DBS-based method for population-level surveillance, particularly in resource-limited settings and for children's health.

Micelle-Formulated Juglone Effectively Targets Pancreatic Cancer and Remodels the Tumor Microenvironment.

Pancreatic cancer remains a formidable challenge due to limited treatment options and its aggressive nature. In recent years, the naturally occurring anticancer compound juglone has emerged as a potential therapeutic candidate, showing promising results in inhibiting tumor growth and inducing cancer cell apoptosis. However, concerns over its toxicity have hampered juglone's clinical application. To address this issue, we have explored the use of polymeric micelles as a delivery system for juglone in pancreatic cancer treatment. These micelles, formulated using Poloxamer 407 and D-α-Tocopherol polyethylene glycol 1000 succinate, offer an innovative solution to enhance juglone's therapeutic potential while minimizing toxicity. In-vitro studies have demonstrated that micelle-formulated juglone (JM) effectively decreases proliferation and migration and increases apoptosis in pancreatic cancer cell lines. Importantly, in-vivo, JM exhibited no toxicity, allowing for increased dosing frequency compared to free drug administration. In mice, JM significantly reduced tumor growth in subcutaneous xenograft and orthotopic pancreatic cancer models. Beyond its direct antitumor effects, JM treatment also influenced the tumor microenvironment. In immunocompetent mice, JM increased immune cell infiltration and decreased stromal deposition and activation markers, suggesting an immunomodulatory role. To understand JM's mechanism of action, we conducted RNA sequencing and subsequent differential expression analysis on tumors that were treated with JM. The administration of JM treatment reduced the expression levels of the oncogenic protein MYC, thereby emphasizing its potential as a focused, therapeutic intervention. In conclusion, the polymeric micelles-mediated delivery of juglone holds excellent promise in pancreatic cancer therapy. This approach offers improved drug delivery, reduced toxicity, and enhanced therapeutic efficacy.

Deregulating MYC in a model of HER2+ breast cancer mimics human intertumoral heterogeneity.

The c-MYC (MYC) oncoprotein is often overexpressed in human breast cancer; however, its role in driving disease phenotypes is poorly understood. Here, we investigate the role of MYC in HER2+ disease, examining the relationship between HER2 expression and MYC phosphorylation in HER2+ patient tumors and characterizing the functional effects of deregulating MYC expression in the murine NeuNT model of amplified-HER2 breast cancer. Deregulated MYC alone was not tumorigenic, but coexpression with NeuNT resulted in increased MYC Ser62 phosphorylation and accelerated tumorigenesis. The resulting tumors were metastatic and associated with decreased survival compared with NeuNT alone. MYC;NeuNT tumors had increased intertumoral heterogeneity including a subtype of tumors not observed in NeuNT tumors, which showed distinct metaplastic histology and worse survival. The distinct subtypes of MYC;NeuNT tumors match existing subtypes of amplified-HER2, estrogen receptor-negative human tumors by molecular expression, identifying the preclinical utility of this murine model to interrogate subtype-specific differences in amplified-HER2 breast cancer. We show that these subtypes have differential sensitivity to clinical HER2/EGFR-targeted therapeutics, but small-molecule activators of PP2A, the phosphatase that regulates MYC Ser62 phosphorylation, circumvents these subtype-specific differences and ubiquitously suppresses tumor growth, demonstrating the therapeutic utility of this approach in targeting deregulated MYC breast cancers.

The development of sexual stage malaria gametocytes in a Wave Bioreactor.

BACKGROUND: Blocking malaria gametocyte development in RBCs or their fertilization in the mosquito gut can prevent infection of the mosquito vector and passage of disease to the human host. A 'transmission blocking' strategy is a component of future malaria control. However, the lack of robust culture systems for producing large amounts of Plasmodium falciparum gametocytes has limited our understanding of sexual-stage malaria biology and made vaccine or chemotherapeutic discoveries more difficult. METHODS: The Wave BioreactorTM 20/50 EHT culture system was used to develop a convenient and low-maintenance protocol for inducing commitment of P. falciparum parasites to gametocytogenesis. Culture conditions were optimised to obtain mature stage V gametocytes within 2 weeks in a large-scale culture of up to a 1 l. RESULTS: We report a simple method for the induction of gametocytogenesis with N-acetylglucosamine (10 mM) within a Wave Bioreactor. By maintaining the culture for 14-16 days as many as 100 million gametocytes (stage V) were produced in a 1 l culture. Gametocytes isolated using magnetic activated cell sorting (MACS) columns were frozen in aliquots for storage. These were revitalised by thawing and shown to retain their ability to exflagellate and infect mosquitoes (Anopheles stephansi). CONCLUSIONS: The production of gametocytes in the Wave Bioreactor under GMP-compliant conditions will not only facilitate cellular, developmental and molecular studies of gametocytes, but also the high-throughput screening for new anti-malarial drugs and, possibly, the development of whole-cell gametocyte or sporozoite-based vaccines.

Large-scale growth of the Plasmodium falciparum malaria parasite in a wave bioreactor.

We describe methods for the large-scale in vitro culturing of synchronous and asynchronous blood-stage Plasmodium falciparum parasites in sterile disposable plastic bioreactors controlled by wave-induced motion (wave bioreactor). These cultures perform better than static flask cultures in terms of preserving parasite cell cycle synchronicity and reducing the number of multiple-infected erythrocytes. The straight-forward methods described here will facilitate the large scale production of malaria parasites for antigen and organelle isolation and characterisation, for the high throughput screening of compound libraries with whole cells or extracts, and the development of live- or whole-cell malaria vaccines under good manufacturing practice compliant standards.