Structural pharmacology and therapeutic potential of 5-methoxytryptamines.

Psychedelic substances such as lysergic acid diethylamide (LSD) and psilocybin show potential for the treatment of various neuropsychiatric disorders1-3. These compounds are thought to mediate their hallucinogenic and therapeutic effects through the serotonin (5-hydroxytryptamine (5-HT)) receptor 5-HT2A (ref. 4). However, 5-HT1A also plays a part in the behavioural effects of tryptamine hallucinogens5, particularly 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), a psychedelic found in the toxin of Colorado River toads6. Although 5-HT1A is a validated therapeutic target7,8, little is known about how psychedelics engage 5-HT1A and which effects are mediated by this receptor. Here we map the molecular underpinnings of 5-MeO-DMT pharmacology through five cryogenic electron microscopy (cryo-EM) structures of 5-HT1A, systematic medicinal chemistry, receptor mutagenesis and mouse behaviour. Structure-activity relationship analyses of 5-methoxytryptamines at both 5-HT1A and 5-HT2A enable the characterization of molecular determinants of 5-HT1A signalling potency, efficacy and selectivity. Moreover, we contrast the structural interactions and in vitro pharmacology of 5-MeO-DMT and analogues to the pan-serotonergic agonist LSD and clinically used 5-HT1A agonists. We show that a 5-HT1A-selective 5-MeO-DMT analogue is devoid of hallucinogenic-like effects while retaining anxiolytic-like and antidepressant-like activity in socially defeated animals. Our studies uncover molecular aspects of 5-HT1A-targeted psychedelics and therapeutics, which may facilitate the future development of new medications for neuropsychiatric disorders.

Expansion of the sagittal suture induces proliferation of skeletal stem cells and sustains endogenous calvarial bone regeneration.

In newborn humans, and up to approximately 2 y of age, calvarial bone defects can naturally regenerate. This remarkable regeneration potential is also found in newborn mice and is absent in adult mice. Since previous studies showed that the mouse calvarial sutures are reservoirs of calvarial skeletal stem cells (cSSCs), which are the cells responsible for calvarial bone regeneration, here we hypothesized that the regenerative potential of the newborn mouse calvaria is due to a significant amount of cSSCs present in the newborn expanding sutures. Thus, we tested whether such regenerative potential can be reverse engineered in adult mice by artificially inducing an increase of the cSSCs resident within the adult calvarial sutures. First, we analyzed the cellular composition of the calvarial sutures in newborn and in older mice, up to 14-mo-old mice, showing that the sutures of the younger mice are enriched in cSSCs. Then, we demonstrated that a controlled mechanical expansion of the functionally closed sagittal sutures of adult mice induces a significant increase of the cSSCs. Finally, we showed that if a calvarial critical size bone defect is created simultaneously to the mechanical expansion of the sagittal suture, it fully regenerates without the need for additional therapeutic aids. Using a genetic blockade system, we further demonstrate that this endogenous regeneration is mediated by the canonical Wnt signaling. This study shows that controlled mechanical forces can harness the cSSCs and induce calvarial bone regeneration. Similar harnessing strategies may be used to develop novel and more effective bone regeneration autotherapies.

The Effect of Cellulose Nanocrystal Reassembly on Latex-Based Pressure-Sensitive Adhesive Performance.

Different cellulose nanocrystal (CNC) forms (dried vs never-dried) can lead to different degrees of CNC reassembly, the formation of nanofibril-like structures, in nanocomposite latex-based pressure-sensitive adhesive (PSA) formulations. CNC reassembly is also affected by CNC sonication and loading as well as the protocol used for CNC addition to the polymerization. In this study, carboxylated CNCs (cCNCs) were incorporated into a seeded, semibatch, 2-ethylhexyl acrylate/methyl methacrylate/styrene emulsion polymerization and cast as pressure-sensitive adhesive (PSA) films. The addition of CNCs led to a simultaneous increase in tack strength, peel strength, and shear adhesion, avoiding the typical trade-off between the adhesive and cohesive strength. Increased CNC reassembly resulted from the use of dried, redispersed, and sonicated cCNCs, along with increased cCNC loading and addition of the cCNCs at the seed stage of the polymerization. The increased degree of CNC reassembly was shown to significantly increase the shear adhesion by enhancing the elastic modulus of the PSA films.

CO2-responsive gels.

CO2-responsive materials undergo a change in chemical or physical properties in response to the introduction or removal of CO2. The use of CO2 as a stimulus is advantageous as it is abundant, benign, inexpensive, and it does not accumulate in a system. Many CO2-responsive materials have already been explored including polymers, latexes, surfactants, and catalysts. As a sub-set of CO2-responsive polymers, the study of CO2-responsive gels (insoluble, cross-linked polymers) is a unique discipline due to the unique set of changes in the gels brought about by CO2 such as swelling or a transformed morphology. In the past 15 years, CO2-responsive gels and self-assembled gels have been investigated for a variety of emerging potential applications, reported in 90 peer-reviewed publications. The two most widely exploited properties include the control of flow (fluids) via CO2-triggered aggregation and their capacity for reversible CO2 absorption-desorption, leading to applications in Enhanced Oil Recovery (EOR) and CO2 sequestration, respectively. In this paper, we review the preparation, properties, and applications of these CO2-responsive gels, broadly classified by particle size as nanogels, microgels, aerogels, and macrogels. We have included a section on CO2-induced self-assembled gels (including poly(ionic liquid) gels).

Damaging variants in FOXI3 cause microtia and craniofacial microsomia.

PURPOSE: Craniofacial microsomia (CFM) represents a spectrum of craniofacial malformations, ranging from isolated microtia with or without aural atresia to underdevelopment of the mandible, maxilla, orbit, facial soft tissue, and/or facial nerve. The genetic causes of CFM remain largely unknown. METHODS: We performed genome sequencing and linkage analysis in patients and families with microtia and CFM of unknown genetic etiology. The functional consequences of damaging missense variants were evaluated through expression of wild-type and mutant proteins in vitro. RESULTS: We studied a 5-generation kindred with microtia, identifying a missense variant in FOXI3 (p.Arg236Trp) as the cause of disease (logarithm of the odds = 3.33). We subsequently identified 6 individuals from 3 additional kindreds with microtia-CFM spectrum phenotypes harboring damaging variants in FOXI3, a regulator of ectodermal and neural crest development. Missense variants in the nuclear localization sequence were identified in cases with isolated microtia with aural atresia and found to affect subcellular localization of FOXI3. Loss of function variants were found in patients with microtia and mandibular hypoplasia (CFM), suggesting dosage sensitivity of FOXI3. CONCLUSION: Damaging variants in FOXI3 are the second most frequent genetic cause of CFM, causing 1% of all cases, including 13% of familial cases in our cohort.

Isolated frontosphenoidal craniosynostosis: An argument for genetic testing.

Isolated frontosphenoidal craniosynostosis (IFSC) is a rare congenital defect defined as premature fusion of the frontosphenoidal suture in the absence of other suture fusion. Until now, IFSC was regarded as a phenomenon with an unclear genetic etiology. We have identified three cases with IFSC with underlying syndromic diagnoses that were attributable to pathogenic mutations involving FGFR3 and MN1, as well as 22q11.2 deletion syndrome. These findings suggest a genetic predisposition to IFSC may exist, thereby justifying the recommendation for genetic evaluation and testing in this population. Furthermore, due to improved imaging resolution, cases of IFSC are now readily identified. With the identification of IFSC with underlying genetic diagnoses, in combination with significant improvements in imaging resolution, we recommend genetic evaluation in children with IFSC.

Unexpected role of SIX1 variants in craniosynostosis: expanding the phenotype of SIX1-related disorders.

BACKGROUND: Pathogenic heterozygous SIX1 variants (predominantly missense) occur in branchio-otic syndrome (BOS), but an association with craniosynostosis has not been reported. METHODS: We investigated probands with craniosynostosis of unknown cause using whole exome/genome (n=628) or RNA (n=386) sequencing, and performed targeted resequencing of SIX1 in 615 additional patients. Expression of SIX1 protein in embryonic cranial sutures was examined in the Six1nLacZ/+ reporter mouse. RESULTS: From 1629 unrelated cases with craniosynostosis we identified seven different SIX1 variants (three missense, including two de novo mutations, and four nonsense, one of which was also present in an affected twin). Compared with population data, enrichment of SIX1 loss-of-function variants was highly significant (p=0.00003). All individuals with craniosynostosis had sagittal suture fusion; additionally four had bilambdoid synostosis. Associated BOS features were often attenuated; some carrier relatives appeared non-penetrant. SIX1 is expressed in a layer basal to the calvaria, likely corresponding to the dura mater, and in the mid-sagittal mesenchyme. CONCLUSION: Craniosynostosis is associated with heterozygous SIX1 variants, with possible enrichment of loss-of-function variants compared with classical BOS. We recommend screening of SIX1 in craniosynostosis, particularly when sagittal±lambdoid synostosis and/or any BOS phenotypes are present. These findings highlight the role of SIX1 in cranial suture homeostasis.

Transcriptomic Signatures of Single-Suture Craniosynostosis Phenotypes.

Craniosynostosis is a birth defect where calvarial sutures close prematurely, as part of a genetic syndrome or independently, with unknown cause. This study aimed to identify differences in gene expression in primary calvarial cell lines derived from patients with four phenotypes of single-suture craniosynostosis, compared to controls. Calvarial bone samples (N = 388 cases/85 controls) were collected from clinical sites during reconstructive skull surgery. Primary cell lines were then derived from the tissue and used for RNA sequencing. Linear models were fit to estimate covariate adjusted associations between gene expression and four phenotypes of single-suture craniosynostosis (lambdoid, metopic, sagittal, and coronal), compared to controls. Sex-stratified analysis was also performed for each phenotype. Differentially expressed genes (DEGs) included 72 genes associated with coronal, 90 genes associated with sagittal, 103 genes associated with metopic, and 33 genes associated with lambdoid craniosynostosis. The sex-stratified analysis revealed more DEGs in males (98) than females (4). There were 16 DEGs that were homeobox (HOX) genes. Three TFs (SUZ12, EZH2, AR) significantly regulated expression of DEGs in one or more phenotypes. Pathway analysis identified four KEGG pathways associated with at least one phenotype of craniosynostosis. Together, this work suggests unique molecular mechanisms related to craniosynostosis phenotype and fetal sex.

Polysaccharide-Based Nanoparticles as Pickering Emulsifiers in Emulsion Formulations and Heterogenous Polymerization Systems.

Bio-based Pickering emulsifiers are a nontoxic alternative to surfactants in emulsion formulations and heterogenous polymerizations. Recent demand for biocompatible and sustainable formulations has accelerated academic interest in polysaccharide-based nanoparticles as Pickering emulsifiers. Despite the environmental advantages, the inherent hydrophilicity of polysaccharides and their nanoparticles limits efficiency and application range. Modification of the polysaccharide surface is often required in the development of ultrastable, functional, and water-in-oil (W/O) systems. Complex surface modification calls into question the sustainability of polysaccharide-based nanoparticles and is identified as a significant barrier to commercialization. This review summarizes the use of nanocelluloses, -starches, and -chitins as Pickering emulsifiers, highlights trends and best practices in surface modification, and provides recommendations to expedite commercialization.

Integrating webinars to enhance curriculum implementation: AMEE Guide No. 136.

Webinars have been used in medical education since 2006 and are now part of the educational offerings of many organizations, including universities, societies, and industry for healthcare trainees and professionals. They are frequently used for continuing medical education (CME) and continuing professional development (CPD) for internal medicine physicians, pharmacists, nurses, and surgeons. There is very limited evidence for the positive impact of these educational events on patient care, however, there is literature that suggests they have educational value for various audiences. Based on our own extensive experience, evaluation data, and key findings over the past decade and a review of the literature, this guide proposes best practices for planning, developing, delivering and evaluating webinars as a part of your curriculum. We propose six phases with steps and questions to help achieve the key purposes of each phase.

Utility of DNA barcoding in native Oreochromis species.

The importance of Oreochromis in worldwide aquaculture and regional fisheries motivates the study of their genetic diversity in their native range. In this article, all mitochondrial cytochrome c oxidase subunit I gene (COI) sequences of Oreochromis species are retrieved from Barcode of Life Data system to quantify the available DNA barcoding information from wild individuals collected within the native ranges of the respective species. It is found that 70% of the known species in the genus still lack a COI barcode, and only 15% of the available sequences are from within the respective native ranges. Many of the available sequences have been produced from specimens acquired from aquaculture and introduced, naturalized populations, making the assessment of variation within the original native range challenging. Analyses of the wild-collected fraction of available sequences indicated the presence of cryptic lineages within Nile tilapia Oreochromis niloticus and O. schwebischi, the occurrence of potential introgressive hybridization between O. niloticus and blue tilapia O. aureus, and potential ancestral polymorphism between Karonga tilapia O. karongae and black tilapia O. placidus. This article also reports a case of misidentification of O. mweruensis as longfin tilapia O. macrochir. These results stress the importance of improving the knowledge of genetic variation within the native ranges of Oreochromis species for better-informed conservation of these natural resources.

A genome-wide association study implicates the BMP7 locus as a risk factor for nonsyndromic metopic craniosynostosis.

Our previous genome-wide association study (GWAS) for sagittal nonsyndromic craniosynostosis (sNCS) provided important insights into the genetics of midline CS. In this study, we performed a GWAS for a second midline NCS, metopic NCS (mNCS), using 215 non-Hispanic white case-parent triads. We identified six variants with genome-wide significance (P ≤ 5 × 10-8): rs781716 (P = 4.71 × 10-9; odds ratio [OR] = 2.44) intronic to SPRY3; rs6127972 (P = 4.41 × 10-8; OR = 2.17) intronic to BMP7; rs62590971 (P = 6.22 × 10-9; OR = 0.34), located ~ 155 kb upstream from TGIF2LX; and rs2522623, rs2573826, and rs2754857, all intronic to PCDH11X (P = 1.76 × 10-8, OR = 0.45; P = 3.31 × 10-8, OR = 0.45; P = 1.09 × 10-8, OR = 0.44, respectively). We performed a replication study of these variants using an independent non-Hispanic white sample of 194 unrelated mNCS cases and 333 unaffected controls; only the association for rs6127972 (P = 0.004, OR = 1.45; meta-analysis P = 1.27 × 10-8, OR = 1.74) was replicated. Our meta-analysis examining single nucleotide polymorphisms common to both our mNCS and sNCS studies showed the strongest association for rs6127972 (P = 1.16 × 10-6). Our imputation analysis identified a linkage disequilibrium block encompassing rs6127972, which contained an enhancer overlapping a CTCF transcription factor binding site (chr20:55,798,821-55,798,917) that was significantly hypomethylated in mesenchymal stem cells derived from fused metopic compared to open sutures from the same probands. This study provides additional insights into genetic factors in midline CS.

SMAD6 variants in craniosynostosis: genotype and phenotype evaluation.

PURPOSE: Enrichment of heterozygous missense and truncating SMAD6 variants was previously reported in nonsyndromic sagittal and metopic synostosis, and interaction of SMAD6 variants with a common polymorphism nearBMP2 (rs1884302) was proposed to contribute to inconsistent penetrance. We determined the occurrence of SMAD6 variants in all types of craniosynostosis, evaluated the impact of different missense variants on SMAD6 function, and tested independently whether rs1884302 genotype significantly modifies the phenotype. METHODS: We performed resequencing of SMAD6 in 795 unsolved patients with any type of craniosynostosis and genotyped rs1884302 in SMAD6-positive individuals and relatives. We examined the inhibitory activity and stability of SMAD6 missense variants. RESULTS: We found 18 (2.3%) different rare damaging SMAD6 variants, with the highest prevalence in metopic synostosis (5.8%) and an 18.3-fold enrichment of loss-of-function variants comparedwith gnomAD data (P < 10-7). Combined with eight additional variants, ≥20/26 were transmitted from an unaffected parent but rs1884302 genotype did not predict phenotype. CONCLUSION: Pathogenic SMAD6 variants substantially increase the risk of both nonsyndromic and syndromic presentations of craniosynostosis, especially metopic synostosis. Functional analysis is important to evaluate missense variants. Genotyping of rs1884302 is not clinically useful. Mechanisms to explain the remarkable diversity of phenotypes associated with SMAD6 variants remain obscure.

Correction: SMAD6 variants in craniosynostosis: genotype and phenotype evaluation.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Surface Modification of Cellulose Nanocrystals via RAFT Polymerization of CO2-Responsive Monomer-Tuning Hydrophobicity.

Cellulose nanocrystals (CNCs) were converted into a CO2-responsive composite nanomaterial by grafting poly(dimethylaminoethyl methacrylate) (PDMAEMA), poly(diethylaminoethyl methacrylate) (PDEAEMA), and poly(diisopropylaminoethyl methacrylate) (PDPAEMA) onto its surface using both grafting-to and grafting-from approaches. The zeta potential (ζ) of the graft-modified CNC could be reversibly switched by protonation/deprotonation of the tertiary amine groups simply by sparging with CO2 and N2, respectively. Depending on the grafting density and the molecular weight of the polymer grafts, CNC can form stable aqueous dispersions at either mildly acidic pH (under CO2) or mildly basic (under N2) conditions. Moreover, it was also determined that the CNC hydrophobicity, assessed using phase-shuttling experiments at different pH values, was also dependent on both the grafting density and molecular weight of the polymer grafts, thereby making it possible to easily tune CNC dispersibility and/or hydrophobicity.

Microsuspension Polymerization of Styrene Using Cellulose Nanocrystals as Pickering Emulsifiers: On the Evolution of Latex Particles.

We report a mechanistic study of the microsuspension polymerization of styrene stabilized by cellulose nanocrystals (CNCs) in its native form as well as graft-modified with copolymers of styrene and N-3-(dimethylamino)propyl methacrylamide (DMAPMAm) or N,N-(diethylamino)ethyl methacrylate (DEAEMA). Native CNCs and graft-modified CNCs were shown to form stable styrene emulsions with an average droplet diameter of 18-20 and 5-9 µm, respectively. Initiators of widely varying water solubilities [2,2'-azobisisobutyronitrile (AIBN), 2-2'-azobis(2,4-dimethylvaleronitrile) (Vazo-52), and lauroyl peroxide (LPO)] were employed for the polymerizations. The type of initiator and the type of CNC were shown to directly affect the microsuspension polymerization kinetics, particle size, and molecular weight distribution. Using AIBN and Vazo-52, submicron latex particles were observed in the final latex in addition to the desired 3-20 µm CNC-armored microsuspension particles. The resulting latex and microsuspension polystyrene particles were studied for their CNC coverage and surface charge. We found that the presence of CNCs in the aqueous phase did not lead to Pickering emulsion polymerization by heterogeneous nucleation.

Polymer Colloids: Synthesis Fundamentals to Applications.

This special issue of Biomacromolecules highlights research from The International Polymer Colloid Group (IPCG), which was founded in 1972 as a forum for the exchange of ideas and emerging research activities for scientists and engineers from both academia and industry who study or use polymer colloids. The increasing relevance of polymeric structures with colloidal dimensions to biomacromolecules research provided the impetus for organizing this special issue. The IPCG is composed of over 120 researchers from over 20 countries who are elected to membership. Activities comprise annual symposia including a biennial International Polymer Colloid Group Research Conference and a semiannual newsletter that incorporates a summary of recent (including unpublished) research results from our members.

Graft Modification of Starch Nanoparticles Using Nitroxide-Mediated Polymerization and the "Grafting to" Approach.

Starch nanoparticles (SNP) were modified with synthetic polymers using the "grafting to" approach and nitroxide-mediated polymerization. SG1-capped poly(methyl methacrylate-co-styrene) (P(MMA-co-S)) copolymers with low dispersity and high degree of livingness were first synthesized in bulk. These macroalkoxyamines were then grafted to vinyl benzyl-functionalized SNP to obtain biosynthetic hybrids. The grafted materials, SNP-g-P(MMA-co-S), were characterized by 1H NMR, FTIR, TGA, and elemental analysis. The total amount of grafted polymer and the grafting efficiency were evaluated for different molecular weights (5870-12150 g·mol-1) of the grafted polymer, the polymer addition approach (batch or semibatch) and the initial polymer loading (2.5, 5, or 10 g polymer/g SNP). The proposed approach presented in this work to graft modify SNP allows for a precise surface modification of the nanoparticles, while permitting that the final properties of the resulting biohybrid to be tunable according to the choice of polymer grafted.

Theoretical Framework of a Polydisperse Cell Filtration Model.

Filtration via a porous medium is a ubiquitous process where high-fidelity physical models are needed. The classical cell model oversimplifies the filtration medium and results in biased and inaccurate predictions of the filter performance. This paper presents the discrete framework of a polydisperse cell model that can incorporate any measured pore size distribution. A new equation connecting the polydisperse cell efficiencies and the medium efficiency is derived from first principles. For ceramic filters, the discrete model demonstrates a generic prediction capability of the filtration efficiency with a root-mean-squared difference of 5.4%, while the counterpart of the classical cell model is 26.4%. In addition, the discrete model eliminates the biased predictions of the classical cell model on sub-100 nm particles.

Development and assessment of competency-based neurotrauma course curriculum for international neurosurgery residents and neurosurgeons.

OBJECTIVE: Traumatic brain injuries (TBIs) are a significant disease burden worldwide. It is imperative to improve neurosurgeons' training during and after their medical residency with appropriate neurotrauma competencies. Unfortunately, the development of these competencies during neurosurgeons' careers and in daily practice is very heterogeneous. This article aimed to describe the development and evaluation of a competency-based international course curriculum designed to address a broad spectrum of needs for taking care of patients with neurotrauma with basic and advanced interventions in different scenarios around the world. METHODS: A committee of 5 academic neurosurgeons was involved in the task of building this course curriculum. The process started with the identification of the problems to be addressed and the subsequent performance needed. After this, competencies were defined. In the final phase, educational activities were designed to achieve the intended learning outcomes. In the end, the entire process resulted in competency and outcomes-based education strategy, including a definition of all learning activities and learning outcomes (curriculum), that can be integrated with a faculty development process, including training. Further development was completed by 4 additional academic neurosurgeons supported by a curriculum developer specialist and a project manager. After the development of the course curriculum, template programs were developed with core and optional content defined for implementation and evaluation. RESULTS: The content of the course curriculum is divided into essentials and advanced concepts and interventions in neurotrauma care. A mixed sample of 1583 neurosurgeons and neurosurgery residents attending 36 continuing medical education activities in 30 different cities around the world evaluated the course. The average satisfaction was 97%. The average usefulness score was 4.2, according to the Likert scale. CONCLUSIONS: An international competency-based course curriculum is an option for creating a well-accepted neurotrauma educational process designed to address a broad spectrum of needs that a neurotrauma practitioner faces during the basic and advanced care of patients in different regions of the world. This process may also be applied to other areas of the neurosurgical knowledge spectrum. Moreover, this process allows worldwide standardization of knowledge requirements and competencies, such that training may be better benchmarked between countries regardless of their income level.