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α-l-(3-2)-Threofuranosyl nucleic acid (TNA) pairs with itself, cross-pairs with DNA and RNA, and shows promise as a tool in synthetic genetics, diagnostics, and oligonucleotide therapeutics. We studied in vitro primer insertion and extension reactions catalyzed by human trans-lesion synthesis (TLS) DNA polymerase η (hPol η) opposite a TNA-modified template strand without and in combination with O4-alkyl thymine lesions. Across TNA-T (tT), hPol η inserted mostly dAMP and dGMP, dTMP and dCMP with lower efficiencies, followed by extension of the primer to a full-length product. hPol η inserted dAMP opposite O4-methyl and -ethyl analogs of tT, albeit with reduced efficiencies relative to tT. Crystal structures of ternary hPol η complexes with template tT and O4-methyl tT at the insertion and extension stages demonstrated that the shorter backbone and different connectivity of TNA compared to DNA (3 → 2 versus 5 → 3, respectively) result in local differences in sugar orientations, adjacent phosphate spacings, and directions of glycosidic bonds. The 3-OH of the primers terminal thymine was positioned at 3.4 Å on average from the α-phosphate of the incoming dNTP, consistent with insertion opposite and extension past the TNA residue by hPol η. Conversely, the crystal structure of a ternary hPol η·DNA·tTTP complex revealed that the primers terminal 3-OH was too distant from the tTTP α-phosphate, consistent with the inability of the polymerase to incorporate TNA. Overall, our study provides a better understanding of the tolerance of a TLS DNA polymerase vis-à-vis unnatural nucleotides in the template and as the incoming nucleoside triphosphate.

Threofuranosyl nucleic acid (TNA), an artificial genetic polymer known for its nuclease resistance and acid stability, has grown in popularity as a genetically-encoded material for applications in synthetic biology and biomedicine. TNA oligonucleotide synthesis requires enzymatic or solid phase synthesis pathways that rely on monomer building blocks that are not commercially available and can only be obtained by chemical synthesis. Here we present a synthetic route to 7-deaza-7-modified tGTP and phosphoramidite analogs that is operationally simpler than our previously described strategy. The new methodology offers an HPLC-free route to tGTP analogs that are recognized by engineered TNA polymerases and can be incorporated with continued TNA synthesis.

Chemical strategies that augment genetic polymers with amino acid residues that are overrepresented on the paratope surface of an antibody offer a promising route for enhancing the binding properties of nucleic acid aptamers. Here, we describe the chemical synthesis of α-l-threofuranosyl cytidine nucleoside triphosphate (tCTP) carrying either a benzyl or phenylpropyl side chain at the pyrimidine C-5 position. Polymerase recognition studies indicate that both substrates are readily incorporated into a full-length α-l-threofuranosyl nucleic acid (TNA) product by extension of a DNA primer-template duplex with an engineered TNA polymerase. Similar primer extension reactions performed using nucleoside triphosphate mixtures containing both C-5 modified tCTP and C-5 modified tUTP substrates enable the production of doubly modified TNA strands for a panel of 20 chemotype combinations. Kinetic measurements reveal faster on-rates (kon) and tighter binding affinity constants (Kd) for engineered versions of TNA aptamers carrying chemotypes at both pyrimidine positions as compared to their singly modified counterparts. These findings expand the chemical space of evolvable non-natural genetic polymers by offering a path for improving the quality of biologically stable TNA aptamers for future clinical applications.

Immune checkpoint inhibitors (ICI)-based combinations have become the standard first-line treatment for advanced clear cell renal cell carcinoma (ccRCC). Despite significant improvements in survival and the achievement of sustained long-term responses, a subset of patients remains refractory to ICI, and most will eventually develop resistance. Thus, identifying predictive biomarkers for ICI efficacy and resistance is essential for optimizing therapeutic strategies. Up to now, tissue-based biomarkers have not been successful as predictive biomarkers in RCC. Circulating blood-based biomarkers offer a promising alternative. These biomarkers, including circulating immune cells, soluble factors, tumor-derived markers, and those based on metabolomics, are less invasive, offer reproducibility over time, and provide a comprehensive assessment of tumor biology and patient immune status, as well as allow dynamic monitoring during treatment. This review aims to evaluate the current evidence on the different candidate circulating biomarkers being investigated for their potential to predict ICI efficacy in RCC patients.

Abstract Skin healing is a complex and dynamic physiological process that follows mechanical alteration of the skin barrier. Under normal conditions, this complex process can be divided into at least three continuous and overlapping phases: an inflammatory reaction, a proliferative phase that leads to tissue reconstruction and a phase of tissue remodeling. Macrophages critically contribute to the physiological cascade for tissue repair. In fact, as the inflammatory phase progresses, macrophage gene expression gradually shifts from pro-inflammatory M1-like to pro-resolutive M2-like characteristics, which is critical for entry into the repair phase. A dysregulation in this macrophage’ shift phenotype leads to the persistence of the inflammatory phase. Mesenchymal stromal cells and specifically the MSC-derived from adipose tissue (ADSCs) are more and more use to treat inflammatory diseases and several studies have demonstrated that ADSCs promote the wound healing thanks to their neoangiogenic, immunomodulant and regenerative properties. In several studies, ADSCs and macrophages have been injected directly into the wound bed, but the delivery of exogenous cells directly to the wound raise the problem of cell engraftment and preservation of pro-resolutive phenotype and viability of the cells. Complementary approaches have therefore been explored, such as the use of biomaterials enriched with therapeutic cell to improve cell survival and function. This review will present a background of the current scaffold models, using adipose derived stromal-cells and macrophage as therapeutic cells for wound healing, through a discussion on the potential impact for future applications in skin regeneration. According to the PRISMA statement, we resumed data from investigations reporting the use ADSCs and bioscaffolds and data from macrophages behavior with functional biomaterials in wound healing models. In the era of tissue engineering, functional biomaterials, that can maintain cell delivery and cellular viability, have had a profound impact on the development of dressings for the treatment of chronic wounds. Promising results have been showed in pre-clinical reports using ADSCs- and macrophages-based scaffolds to accelerate and to improve the quality of the cutaneous healing.

Abstract Background Several recent global events may have impacted adolescent sleep and exacerbated pre-existing disparities by social positions (i.e., social roles, identity or sociodemographic factors, and/or group memberships that are associated with power and oppression due to the structures and processes in a given society at given time). Current understanding of sleep among adolescents is critical to inform interventions for a more equitable future, given the short and long-term consequences of inadequate sleep on health and well-being. This study aimed to provide contemporary evidence on sleep disparities by key social positions among adolescents in Canada. Methods Cross-sectional analyses were conducted using self-reported data collected during 2020–2021 (the first full school year after the COVID-19 pandemic onset) from 52,138 students (mean [SD] age = 14.9 [1.5]) attending 133 Canadian secondary schools. Multiple regression models were used to test whether sleep quality (how well students slept during past week), duration (weekday, weekend, weighted daily average), and guideline adherence (8–10 h/day) differed by sex and gender, race and ethnicity, and socioeconomic status (SES). Results Females reported a mean [95% CI] difference of -1.7 [-3.7, 0.4] min/day less sleep on weekdays than males, but 7.1 [4.5, 9.6] min/day more sleep on weekends, resulting in no difference in average daily sleep between males and females. Females were less likely to report good quality sleep compared to males (AOR = 0.57 [0.54, 0.60]). SES followed a generally monotonic trend where higher scores were associated with more sleep on weekdays (Δhighest: lowest = -28.6 [-39.5, -17.6]) and weekends (Δhighest: lowest = -17.5 [-3.8, -31.2]) and greater likelihood of higher sleep quality (AORhighest: lowest = 3.04 [2.35, 3.92]). Relative to White adolescents, weekday and average daily sleep duration were lower among all other racial identities; mean differences ranged from ∼ 5–15 min/day, with Black students reporting the least sleep. Conclusions Differences in sleep duration and quality were most profound among adolescents from the lowest and highest SES. Racial disparities were more evident on weekdays. Compensatory weekend sleep appears more pronounced in females than males. Addressing sleep inequities is critical, as a robust predictor of multiple health outcomes.

In vitro evolution strategies have been used for >30 years to generate nucleic acid aptamers against therapeutic targets of interest, including disease-associated proteins. However, this process requires many iterative cycles of selection and amplification, which severely restricts the number of target and library design combinations that can be explored in parallel. Here, we describe a single-round screening approach to aptamer discovery that relies on function-enhancing chemotypes to increase the distribution of high-affinity sequences in a random-sequence library. We demonstrate the success of de novo discovery by affinity selection of threomers against the receptor binding domain of the S1 protein from SARS-CoV-2. Detailed biochemical characterization of the enriched population identified threomers with binding affinity values that are comparable to aptamers produced by conventional SELEX. This work establishes a highly parallelizable path for querying diverse chemical repertoires and may offer a viable route for accelerating the discovery of therapeutic aptamers.

IntroductionPublic health concerns over the impact of social media use (SMU) on adolescent health are growing. We investigated the relationship between SMU and sleep health in adolescents in Canada aged 11 to 17 years. MethodsData from the 2017–2018 Health Behaviour in School-aged Children study were available for 12 557 participants (55.2% female). SMU was categorized by frequency of use (non-active, active and intense) and the presence of addiction-like symptoms (problematic). Mixed effects logistic regression models identified associations between SMU and seven sleep health indicators (insomnia symptoms, daytime wakefulness problems, screen time before bed, meeting sleep duration recommendations, sleep variability and late bedtime on school and non-school days). ResultsCompared to active SMU, non-active SMU was associated with better sleep indicators, except for insomnia symptoms. Intense SMU was associated with greater odds of having poor sleep health indicators (adjusted odds ratio [aORs] from 1.09 to 2.24) and problematic SMU with the highest odds (aORs from 1.67 to 3.24). Associations with problematic SMU were greater among girls than boys, including having a later bedtime on school days (aOR = 3.74 vs. 1.84) and on non-school days (aOR = 4.13 vs. 2.18). Associations between SMU and sleep outcomes did not differ by age group. ConclusionCompared to active SMU, non-active SMU was associated with better sleep indicators, except for insomnia symptoms. Intense SMU was associated with greater odds of having poor sleep health indicators (adjusted odds ratio [aORs] from 1.09 to 2.24) and problematic SMU with the highest odds (aORs from 1.67 to 3.24). Associations with problematic SMU were greater among girls than boys, including having a later bedtime on school days (aOR = 3.74 vs. 1.84) and on non-school days (aOR = 4.13 vs. 2.18). Associations between SMU and sleep outcomes did not differ by age group.

IntroductionLes effets de l’utilisation des médias sociaux sur la santé des adolescents soulèvent de plus en plus de préoccupations en matière de santé publique. Nous avons exploré la relation entre cette utilisation et la santé du sommeil chez les adolescents du Canada de 11 à 17 ans. MéthodologieDes données de l’Enquête sur les comportements de santé des jeunes d’âge scolaire de 2017-2018 étaient disponibles pour 12 557 participants (dont 55,2 % de sexe féminin). Des catégories d’utilisation des médias sociaux ont été établies en fonction de la fréquence (utilisation non active, active ou intensive) et de la présence de symptômes évoquant une dépendance (utilisation problématique). Des modèles de régression logistique à effets mixtes ont révélé des associations entre l’utilisation des médias sociaux et sept indicateurs de la santé du sommeil (symptômes d’insomnie, somnolence diurne, utilisation d’un écran avant de se coucher, respect des recommandations sur la durée du sommeil, variabilité du sommeil, heure de coucher tardive les jours d’école et heure de coucher tardive les jours de repos). RésultatsComparativement à une utilisation active des médias sociaux, une utilisation non active a été associée à de meilleurs résultats des indicateurs de la santé du sommeil, sauf en ce qui concerne les symptômes d’insomnie. Une utilisation intensive des médias sociaux a été associée à un risque accru d’indicateurs défavorables de la santé du sommeil (rapport de cotes ajusté [RCa] de 1,09 à 2,24) et une utilisation problématique a été associée au RCa le plus élevé (1,67 à 3,24). Les associations avec une utilisation problématique des médias sociaux étaient plus marquées chez les filles que chez les garçons, en particulier en ce qui concerne l’heure de coucher tardive les jours d’école (RCa = 3,74 vs 1,84) et les jours de repos (RCa = 4,13 vs 2,18). Les associations entre l’utilisation des médias sociaux et les résultats en matière de sommeil ne variaient pas selon la tranche d’âge. ConclusionUne utilisation intensive et une utilisation problématique des médias sociaux ont été associées à un risque accru de troubles du sommeil chez les adolescents du Canada, avec des associations plus marquées chez les filles que chez les garçons. D’autres recherches doivent être menées pour éclaircir les mécanismes à l’origine des associations entre l’utilisation des médias sociaux et le sommeil, de manière à orienter les recommandations en matière de santé publique.

This study investigates how individual-level factors contribute to classroom engagement variations of boys and girls across the elementary school years. Classroom engagement was assessed four times between the ages of 7 and 12 years in a large, representative population-based sample (N = 877) using latent growth modeling. Predictors included the sex of the child, the family income, and the mother's educational attainment when the child was 5 months old, along with the child's early receptive vocabulary, numeracy, motor and attentional skills, motivation to learn, and internalizing and externalizing behaviors measured at age 6 years. On average, classroom engagement progressively improved over time. Child vocabulary skills, attention, intrinsic motivation, and externalizing behaviors predicted initial levels of classroom engagement. Child classroom engagement also showed slower progression over time when receptive vocabulary and attentional skills were high. This trend was slightly different when the analyses were conducted separately for boys and girls. Girls with higher attentional skills and fewer externalizing behaviors at age 6 showed slower improvement in classroom engagement throughout elementary school, while boys did not significantly improve in their classroom engagement. Overall, these results suggest that several individual-level factors contribute to classroom engagement. Children with lower levels of receptive vocabulary, attentional skills, and motivation to learn, and those displaying externalizing behavior may benefit from additional help to boost their classroom engagement.

Xeno-nucleic acids (XNAs) have gained significant interest as synthetic genetic polymers for practical applications in biomedicine, but very little is known about their biophysical properties. Here, we compare the stability and mechanism of acid-mediated degradation of α-l-threose nucleic acid (TNA) to that of natural DNA and RNA. Under acidic conditions and elevated temperature (pH 3.3 at 90°C), TNA was found to be significantly more resistant to acid-mediated degradation than DNA and RNA. Mechanistic insights gained by reverse-phase HPLC and mass spectrometry indicate that the resilience of TNA toward low pH environments is due to a slower rate of depurination caused by induction of the 2'-phosphodiester linkage. Similar results observed for 2',5'-linked DNA and 2'-O-methoxy-RNA implicate the position of the phosphodiester group as a key factor in destabilizing the formation of the oxocarbenium intermediate responsible for depurination and strand cleavage of TNA. Biochemical analysis indicates that strand cleavage occurs by β-elimination of the 2'-phosphodiester linkage to produce an upstream cleavage product with a 2'-threose sugar and a downstream cleavage product with a 3' terminal phosphate. This work highlights the unique physicochemical properties available to evolvable non-natural genetic polymers currently in development for biomedical applications.

Chemical modifications are necessary to ensure the metabolic stability and efficacy of oligonucleotide-based therapeutics. Here, we describe analyses of the α-(l)-threofuranosyl nucleic acid (TNA) modification, which has a shorter 3'-2' internucleotide linkage than the natural DNA and RNA, in the context of small interfering RNAs (siRNAs). The TNA modification enhanced nuclease resistance more than 2'-O-methyl or 2'-fluoro ribose modifications. TNA-containing siRNAs were prepared as triantennary N-acetylgalactosamine conjugates and were tested in cultured cells and mice. With the exceptions of position 2 of the antisense strand and position 11 of the sense strand, the TNA modification did not inhibit the activity of the RNA interference machinery. In a rat toxicology study, TNA placed at position 7 of the antisense strand of the siRNA mitigated off-target effects, likely due to the decrease in the thermodynamic binding affinity relative to the 2'-O-methyl residue. Analysis of the crystal structure of an RNA octamer with a single TNA on each strand showed that the tetrose sugar adopts a C4'-exo pucker. Computational models of siRNA antisense strands containing TNA bound to Argonaute 2 suggest that TNA is well accommodated in the region kinked by the enzyme. The combined data indicate that the TNA nucleotides are promising modifications expected to increase the potency, duration of action, and safety of siRNAs.

High-frequency ultrasonography (> 20 MHz) has allowed for preoperative measurement of melanoma thickness and thus a one-step surgery strategy. The potential benefits of one-step surgery to patients remain unexplored. From June 2022 to August 2023, 2 dermatologists conducted semi-structured individual interviews with patients who had undergone HFUS examination allowing the choice for one-step surgery (group A) and with patients who had had standard two-step surgery (group B). Analysis of interviews with 21 patients (age range 31–81 years) revealed 5 main themes: (a) understanding the diagnosis, highlighting the significance of clear and comprehensive medical explanations; (b) personal factors considered in treatment decisions, including preferences for minimizing surgical procedures; (c) making choices, bearing responsibility, thus showcasing different levels of patient involvement in decision-making; (d) high- frequency ultrasonography reassurance emphasizing the role of medical reassurance, and (e) patient satisfaction, discussing surgical outcomes and the decision-making process. The majority of participants expressed a clear preference for one-step surgery, perceived as a pragmatic and fast surgical strategy while minimizing interventions. In conclusion, the results emphasize the importance of patient-centred care. These insights can guide improved preoperative consultations and enhance shared decision-making between healthcare professionals and patients regarding melanoma treatment strategies.

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, exposed a pressing need for new public health tools for pathogen detection, disease diagnosis, and viral genotyping. REVEALR (RNA-encoded viral nucleic acid analyte reporter) is an isothermal DNAzyme-based point-of-care diagnostic that functions with a detection limit of ∼10 copies/μL when coupled with a preamplification step and can be utilized for viral genotyping of SARS-CoV-2 variants of concern through base pair mismatch recognition in a competitive binding format. Here, we describe an advanced REVEALR platform, termed digital droplet REVEALR (ddREVEALR), that can achieve direct viral detection and absolute sample quantitation utilizing a signal amplification strategy that relies on chemical modifications, DNAzyme multiplexing, and volume compression. Using an AI-assisted image-based readout, ddREVEALR was found to achieve 95% positive predictive agreement from a set of 20 nasal pharyngeal swabs collected at UCI Medical Center in Orange, California. We propose that the combination of amplification-free and protein-free analysis makes ddREVEALR a promising application for direct viral RNA detection of clinical samples.