Human 2'-Deoxynucleoside 5'-Phosphate N-Hydrolase 1: The Catalytic Roles of Tyr24 and Asp80.

The human enzyme 2'-deoxynucleoside 5'-phosphate N-hydrolase 1 (HsDNPH1) catalyses the hydrolysis of 5-hydroxymethyl-2'-deoxyuridine 5'-phosphate to generate 5-hydroxymethyluracil and 2-deoxyribose-5-phosphate via a covalent 5-phospho-2-deoxyribosylated enzyme intermediate. HsDNPH1 is a promising target for inhibitor development towards anticancer drugs. Here, site-directed mutagenesis of conserved active-site residues, followed by HPLC analysis of the reaction and steady-state kinetics are employed to reveal the importance of each of these residues in catalysis, and the reaction pH-dependence is perturbed by each mutation. Solvent deuterium isotope effects indicate no rate-limiting proton transfers. Crystal structures of D80N-HsDNPH1 in unliganded and substrate-bound states, and of unliganded D80A- and Y24F-HsDNPH1 offer atomic level insights into substrate binding and catalysis. The results reveal a network of hydrogen bonds involving the substrate and the E104-Y24-D80 catalytic triad and are consistent with a proposed mechanism whereby D80 is important for substrate positioning, for helping modulate E104 nucleophilicity, and as the general acid in the first half-reaction. Y24 positions E104 for catalysis and prevents a catalytically disruptive close contact between E104 and D80.

DESI-MSI-guided exploration of metabolic-phenotypic relationships reveals a correlation between PI 38:3 and proliferating cells in clear cell renal cell carcinoma via single-section co-registration of multimodal imaging.

A workflow has been evaluated that utilizes a single tissue section to obtain spatially co-registered, molecular, and phenotypical information suitable for AI-enabled image analysis. Desorption electrospray ionization mass spectrometry imaging (DESI-MSI) was used to obtain molecular information followed by conventional histological staining and immunolabelling. The impact of varying DESI-MSI conditions (e.g., heated transfer line (HTL) temperature, scan rate, acquisition time) on the detection of small molecules and lipids as well as on tissue integrity crucial for integration into typical clinical pathology workflows was assessed in human kidney. Increasing the heated transfer line temperature from 150 to 450 °C resulted in a 1.8-fold enhancement in lipid signal at a scan rate of 10 scans/s, while preserving histological features. Moreover, increasing the acquisition speed to 30 scans/s yielded superior lipid signal when compared to 10 scans/s at 150 °C. Tissue morphology and protein epitopes remained intact allowing full histological assessment and further multiplex phenotyping by immunofluorescence (mIF) and immunohistochemistry (mIHC) of the same section. The successful integration of the workflow incorporating DESI-MSI, H&E, and immunolabelling on a single tissue section revealed an accumulation of ascorbic acid in regions of focal chronic inflammatory cell infiltrate within non-cancerous kidney tissue. Additionally, a strong positive correlation between PI 38:3 and proliferating cells was observed in clear cell renal cell carcinoma (ccRCC) showing the utility of this approach in uncovering molecular associations in disease pathology.

Magnifying Networks for Histopathological Images with Billions of Pixels.

Amongst the other benefits conferred by the shift from traditional to digital pathology is the potential to use machine learning for diagnosis, prognosis, and personalization. A major challenge in the realization of this potential emerges from the extremely large size of digitized images, which are often in excess of 100,000 × 100,000 pixels. In this paper, we tackle this challenge head-on by diverging from the existing approaches in the literature-which rely on the splitting of the original images into small patches-and introducing magnifying networks (MagNets). By using an attention mechanism, MagNets identify the regions of the gigapixel image that benefit from an analysis on a finer scale. This process is repeated, resulting in an attention-driven coarse-to-fine analysis of only a small portion of the information contained in the original whole-slide images. Importantly, this is achieved using minimal ground truth annotation, namely, using only global, slide-level labels. The results from our tests on the publicly available Camelyon16 and Camelyon17 datasets demonstrate the effectiveness of MagNets-as well as the proposed optimization framework-in the task of whole-slide image classification. Importantly, MagNets process at least five times fewer patches from each whole-slide image than any of the existing end-to-end approaches.

Deficiency of the paternally-expressed imprinted Peg3 gene in mice has sexually dimorphic consequences for offspring communication and social behaviour.

Introduction: Imprinted genes are expressed from one parental allele as a consequence of epigenetic processes initiated in the germline. Consequently, their ability to influence phenotype depends on their parent-of-origin. Recent research suggests that the sex of the individual expressing the imprinted gene is also important. We have previously reported that genetically wildtype (WT) dams carrying and caring for pups mutant for PEG3 exhibit anxiety-like behaviours and their mutant pups show a reduction in ultrasonic vocalisation when separated from their mothers. Sex-specificity was not examined. Methods: WT female mice were mated with WT, heterozygous Peg3-/+ or homozygous Peg3-/- studs to generate all WT (control), 50:50 mixed or 100% mutant litters, respectively, followed by behavioural assessment of both dams and their pups. Results: We reproduced our original finding that WT dams carrying and caring for 100% mutant litters exhibit postpartum anxiety-like symptoms and delayed pup retrieval. Additionally, these WT dams were found to allocate less time to pup-directed care behaviours relative to controls. Male Peg3-deficient pups demonstrated significantly reduced vocalisation with a more subtle communication deficit in females. Postweaning, male mutants exhibited deficits across a number of key social behaviours as did WT males sharing their environment with mutants. Only modest variations in social behaviour were detected in experimental females. Discussion: We have experimentally demonstrated that Peg3 deficiency confined to the offspring causes anxiety in mouse mothers and atypical behaviour including deficits in communication in their male offspring. A male-specific reduction in expression PEG3 in the fetally-derived placenta has previously been associated with maternal depression in human pregnancy. Maternal mood disorders such as depression and anxiety are associated with delays in language development and neuroatypical behaviour more common in sons. Peg3 deficiency could drive the association of maternal and offspring behavioural disorders reported in humans.

Snapshots of the Reaction Coordinate of a Thermophilic 2'-Deoxyribonucleoside/ribonucleoside Transferase.

Nucleosides are ubiquitous to life and are required for the synthesis of DNA, RNA, and other molecules crucial for cell survival. Despite the notoriously difficult organic synthesis of nucleosides, 2'-deoxynucleoside analogues can interfere with natural DNA replication and repair and are successfully employed as anticancer, antiviral, and antimicrobial compounds. Nucleoside 2'-deoxyribosyltransferase (dNDT) enzymes catalyze transglycosylation via a covalent 2'-deoxyribosylated enzyme intermediate with retention of configuration, having applications in the biocatalytic synthesis of 2'-deoxynucleoside analogues in a single step. Here, we characterize the structure and function of a thermophilic dNDT, the protein from Chroococcidiopsis thermalis (CtNDT). We combined enzyme kinetics with structural and biophysical studies to dissect mechanistic features in the reaction coordinate, leading to product formation. Bell-shaped pH-rate profiles demonstrate activity in a broad pH range of 5.5-9.5, with two very distinct pKa values. A pronounced viscosity effect on the turnover rate indicates a diffusional step, likely product (nucleobase1) release, to be rate-limiting. Temperature studies revealed an extremely curved profile, suggesting a large negative activation heat capacity. We trapped a 2'-fluoro-2'-deoxyarabinosyl-enzyme intermediate by mass spectrometry and determined high-resolution structures of the protein in its unliganded, substrate-bound, ribosylated, 2'-difluoro-2'-deoxyribosylated, and in complex with probable transition-state analogues. We reveal key features underlying (2'-deoxy)ribonucleoside selection, as CtNDT can also use ribonucleosides as substrates, albeit with a lower efficiency. Ribonucleosides are the building blocks of RNA and other key intracellular metabolites participating in energy and metabolism, expanding the scope of use of CtNDT in biocatalysis.

Automated reporting of cervical biopsies using artificial intelligence.

When detected at an early stage, the 5-year survival rate for people with invasive cervical cancer is 92%. Being aware of signs and symptoms of cervical cancer and early detection greatly improve the chances of successful treatment. We have developed an Artificial Intelligence (AI) algorithm, trained and evaluated on cervical biopsies for automated reporting of digital diagnostics. The aim is to increase overall efficiency of pathological diagnosis and to have the performance tuned to high sensitivity for malignant cases. Having a tool for triage/identifying cancer and high grade lesions may potentially reduce reporting time by identifying areas of interest in a slide for the pathologist and therefore improving efficiency. We trained and validated our algorithm on 1738 cervical WSIs with one WSI per patient. On the independent test set of 811 WSIs, we achieved 93.4% malignant sensitivity for classifying slides. Recognising a WSI, with our algorithm, takes approximately 1.5 minutes on the NVIDIA Tesla V100 GPU. Whole slide images of different formats (TIFF, iSyntax, and CZI) can be processed using this code, and it is easily extendable to other formats.

Considerations for Gender-Affirming Hormonal and Surgical Care Among Transgender and Gender Diverse Adolescents and Adults With Congenital Heart Disease.

BACKGROUND: Transgender and gender diverse (TGD) individuals and long-term survivors with adult congenital heart disease (ACHD) are both growing populations with specialized needs. No studies assess temporal trends or evaluate the care of TGD individuals with ACHD. METHODS AND RESULTS: Meetings between congenital cardiology and gender-affirming care specialists identified unique considerations in TGD individuals with ACHD. A retrospective chart review was then performed to describe patient factors and outpatient trends in those with an ACHD diagnosis undergoing gender-affirming hormonal or surgical care (GAHT/S) at 1 adult and 1 pediatric tertiary care center. Thirty-three TGD individuals with ACHD were identified, 21 with a history of GAHT/S. Fourteen (66%) had moderate or complex ACHD, 8 (38%) identified as transgender male, 9 (43%) transgender female, and 4 (19%) other gender identities. Three had undergone gender-affirming surgery. There were zero occurrences of the composite end point of unplanned hospitalization or thrombotic event over 71.1 person-years of gender-affirming care. Median age at first gender-affirming appointment was 16.8 years [interquartile range 14.8-21.5]. The most common treatment modification was changing estradiol administration from oral to transdermal to reduce thrombotic risk (n=3). An increasing trend was observed from zero TGD patients with ACHD attending a gender diversity appointment in 2012 to 14 patients in 2022. CONCLUSIONS: There is a growing population of TGD patients with ACHD and unique medical and psychosocial needs. Future studies must fully evaluate the reassuring safety profile observed in this small cohort. We share 10 actionable care considerations for providers with a goal of overseeing a safe and fulfilling gender transition across all TGD patients with ACHD.

A phase I open-label, dose-escalation study of NUC-3373, a targeted thymidylate synthase inhibitor, in patients with advanced cancer (NuTide:301).

PURPOSE: 5-fluorouracil (5-FU) is inefficiently converted to the active anti-cancer metabolite, fluorodeoxyuridine-monophosphate (FUDR-MP), is associated with dose-limiting toxicities and challenging administration schedules. NUC-3373 is a phosphoramidate nucleotide analog of fluorodeoxyuridine (FUDR) designed to overcome these limitations and replace fluoropyrimidines such as 5-FU. PATIENTS AND METHODS: NUC-3373 was administered as monotherapy to patients with advanced solid tumors refractory to standard therapy via intravenous infusion either on Days 1, 8, 15 and 22 (Part 1) or on Days 1 and 15 (Part 2) of 28-day cycles until disease progression or unacceptable toxicity. Primary objectives were maximum tolerated dose (MTD) and recommended Phase II dose (RP2D) and schedule of NUC-3373. Secondary objectives included pharmacokinetics (PK), and anti-tumor activity. RESULTS: Fifty-nine patients received weekly NUC-3373 in 9 cohorts in Part 1 (n = 43) and 3 alternate-weekly dosing cohorts in Part 2 (n = 16). They had received a median of 3 prior lines of treatment (range: 0-11) and 74% were exposed to prior fluoropyrimidines. Four experienced dose-limiting toxicities: two Grade (G) 3 transaminitis; one G2 headache; and one G3 transient hypotension. Commonest treatment-related G3 adverse event of raised transaminases occurred in < 10% of patients. NUC-3373 showed a favorable PK profile, with dose-proportionality and a prolonged half-life compared to 5-FU. A best overall response of stable disease was observed, with prolonged progression-free survival. CONCLUSION: NUC-3373 was well-tolerated in a heavily pre-treated solid tumor patient population, including those who had relapsed on prior 5-FU. The MTD and RP2D was defined as 2500 mg/m2 NUC-3373 weekly. NUC-3373 is currently in combination treatment studies. TRIAL REGISTRATION: Clinicaltrials.gov registry number NCT02723240. Trial registered on 8th December 2015. https://clinicaltrials.gov/study/NCT02723240 .

The burden of psychological trauma and post-traumatic stress disorder among adults with congenital heart disease: PTSD in ACHD.

Psychological trauma, symptoms of post-traumatic stress disorder (PTSD), and mental health conditions are common in adult congenital heart disease (ACHD). There is a gap in research examining PTSD in ACHD using the current Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) criteria in assessing patient characteristics and experiences with trauma-focused treatment. Surveys were offered to outpatients over a 6-month enrollment period to be completed by way of a QR code on their personal smart phone. Patient-reported items include a detailed medical and psychosocial history, the Oslo social support scale, adverse childhood experiences survey, and the PTSD checklist for DSM-5. Of 158 patients (77% moderate or complex heart disease) who provided complete data, a provisional diagnosis of PTSD was found in 48 patients (30%) using a PTSD checklist for DSM-5 cut-off score of ≥31. A positive PTSD screen was associated with younger age, nonwhite race, presence of heart failure, lower New York Heart Association functional class, lower linear quality of life score, lower Oslo social support scale score, an insecure caregiver relation, period of unemployment, emergency department visits, medication nonadherence, and coexisting mental health disorders. Complexity of heart disease and number of surgical and/or catheter-based interventions were not associated with PTSD, although having undergone no cardiac surgeries until adulthood (aged ≥18 years) was associated with a lower prevalence of PTSD. Those who screened positive for PTSD were more likely to report multiple traumatic events, including noncardiac traumatic events. Only 14 of 48 patients (29%) reported a known diagnosis of PTSD, although 44 patients (92%) reported having ever seen a mental health provider. A total of 18 patients (38%) reported currently having a mental health provider. A total of 30 patients (62%) had heard of at least 1 evidence-based trauma-informed therapy, and 14 (29%) had tried at least 1. In conclusion, using the DSM-5 criteria, we observed a high prevalence of potential PTSD in ACHD associated with several novel cardiac and psychosocial patient factors. Future longitudinal studies will be necessary to establish causality. Few patients with ACHD have been formally diagnosed with PTSD or have experience with evidence-based trauma-informed therapies.