Structural Basis for Teneurin Function in Circuit-Wiring: A Toxin Motif at the Synapse.

Teneurins (TENs) are cell-surface adhesion proteins with critical roles in tissue development and axon guidance. Here, we report the 3.1-Å cryoelectron microscopy structure of the human TEN2 extracellular region (ECR), revealing a striking similarity to bacterial Tc-toxins. The ECR includes a large ß barrel that partially encapsulates a C-terminal domain, which emerges to the solvent through an opening in the mid-barrel region. An immunoglobulin (Ig)-like domain seals the bottom of the barrel while a ß propeller is attached in a perpendicular orientation. We further show that an alternatively spliced region within the ß propeller acts as a switch to regulate trans-cellular adhesion of TEN2 to latrophilin (LPHN), a transmembrane receptor known to mediate critical functions in the central nervous system. One splice variant activates trans-cellular signaling in a LPHN-dependent manner, whereas the other induces inhibitory postsynaptic differentiation. These results highlight the unusual structural organization of TENs giving rise to their multifarious functions.

Structural basis of transcriptional pausing in bacteria.

Transcriptional pausing by multisubunit RNA polymerases (RNAPs) is a key mechanism for regulating gene expression in both prokaryotes and eukaryotes and is a prerequisite for transcription termination. Pausing and termination states are thought to arise through a common, elemental pause state that is inhibitory for nucleotide addition. We report three crystal structures of Thermus RNAP elemental paused elongation complexes (ePECs). The structures reveal the same relaxed, open-clamp RNAP conformation in the ePEC that may arise by failure to re-establish DNA contacts during translocation. A kinked bridge-helix sterically blocks the RNAP active site, explaining how this conformation inhibits RNAP catalytic activity. Our results provide a framework for understanding how RNA hairpin formation stabilizes the paused state and how the ePEC intermediate facilitates termination.

6S RNA Mimics B-Form DNA to Regulate Escherichia coli RNA Polymerase.

Noncoding RNAs (ncRNAs) regulate gene expression in all organisms. Bacterial 6S RNAs globally regulate transcription by binding RNA polymerase (RNAP) holoenzyme and competing with promoter DNA. Escherichia coli (Eco) 6S RNA interacts specifically with the housekeeping σ70-holoenzyme (Eσ70) and plays a key role in the transcriptional reprogramming upon shifts between exponential and stationary phase. Inhibition is relieved upon 6S RNA-templated RNA synthesis. We report here the 3.8 Å resolution structure of a complex between 6S RNA and Eσ70 determined by single-particle cryo-electron microscopy and validation of the structure using footprinting and crosslinking approaches. Duplex RNA segments have A-form C3' endo sugar puckers but widened major groove widths, giving the RNA an overall architecture that mimics B-form promoter DNA. Our results help explain the specificity of Eco 6S RNA for Eσ70 and show how an ncRNA can mimic B-form DNA to directly regulate transcription by the DNA-dependent RNAP.

Migraine headache in patients with spontaneous coronary artery dissection: A report of the iSCAD Registry.

INTRODUCTION: Spontaneous coronary artery dissection (SCAD) is a nonatherosclerotic cause of myocardial infarction. Migraine headache has been reported to be common among patients with SCAD, but the degree of migraine-related disability has not been quantified. METHODS: Clinical data and headache variables were obtained from the baseline assessment of the prospective, multicenter iSCAD Registry. Migraine-related disability was quantified using the self-reported Migraine Disability Assessment (MIDAS). Demographic, clinical, psychosocial, and medical characteristics from data entry forms were compared between patients with and without migraine. RESULTS: Of the 773 patients with available data, 46% reported previous or current migraines. Those with migraines were more likely to be women (96.9% vs 90.3%, p = 0.0003). The presence of underlying carotid fibromuscular dysplasia was associated with migraine (35% vs 27%, p = 0.0175). There was not a significant association with carotid artery dissection and migraine. Current migraine frequency was less than monthly (58%), monthly (24%), weekly (16%), and daily (3%). Triptan use was reported in 32.5% of patients, and 17.5% used daily migraine prophylactic medications. Using the MIDAS to quantify disability related to migraine, 60.2% reported little or no disability, 14.4% mild, 12.7% moderate, and 12.7% severe. The mean MIDAS score was 9.9 (mild to moderate disability). Patients with SCAD had higher rates of depression and anxiety (28.2% vs 17.7% [p = 0.0004] and 35.3% vs 26.7% [p = 0.0099], respectively). CONCLUSIONS: Migraines are common, frequent, and a source of disability in patients with SCAD. The association between female sex, anxiety, and depression may provide some insight for potential treatment modalities.

A comparative study of diaryl urea molecules with and without sulfonamide group on Carbonic anhydrase IX and XII inhibition and its consequence on breast cancer cells.

To investigate the intrinsic relation between carbonic anhydrase inhibition and anticancer activity, we have prepared four sets of diaryl urea molecules and tested for the inhibition of hCA-IX and XII on two breast cancer cell lines. Among 21 compounds, compound J2 (with -SO2NH2 group) and J16 (without -SO2NH2 group) showed the best activity under normoxic and hypoxic conditions. The IC50 values of J16 for MDA-MB-231 and MCF-7 cells, under normoxic condition were 6.3 and 3.7 µM respectively, which are 1.9/3.3 and 15.8 times better than U-4-Nitro and SLC-0111 respectively. Whereas, under the hypoxic condition the corresponding values were 12.4 and 1.1 µM (MDA-MB-231 and MCF-7 cells respectively), which are equal/8 times better than U-4-Nitro. Whereas, J2 showed better IC50 value than U-4-Nitro (6.3 µM) under normoxic condition for both MDA-MB-231 and MCF-7 cells (1.9/2.7 times). Compound J2 inhibits the activity of hCA-IX and XII in nanomolar concentration [Ki values 4.09 and 9.10 nM respectively with selectivity ratio of 1.8 and 0.8 with hCA-II]. The crystal structure and modelling studies demonstrates that the inhibition of CAs arises due to the blocking of the CO2 coordination site of zinc in its catalytic domain. However, J16 was found to be unable to inhibit the activity of hCAs (Ki > 89000 nM). qPCR and western blot analysis showed a significant reduction (1.5 to 20 fold) of the transcription and expression of HIF1A, CA9 and CA12 genes in presence of J2 and J16. Both J2 and J16 found to reduce accumulation of HIF-1α protein by inhibiting the chaperone activity of hHSP70 with IC50 values of 19.4 and 15.3 µM respectively. Perturbation of the hCA-IX and XII activity by binding at active site or by reduced expression or by both leads to the decrease of intracellular pH, which resulted in concomitant increase of reactive oxygen species by 2.6/2.0 (MCF-7) and 2.9/1.8 (MDA-MB-231) fold for J2/J16. Increased cyclin D1 expression in presence of J2 and J16 was presumed to be indirectly responsible for the apoptosis of the cancer cells. Expression of the other apoptosis markers Bcl-2, Bim, caspase 9 and caspase 3 substantiated the apoptosis mechanism. However, decreased transcription/expression of HIF1A/HIF-1α and hCA-IX/XII also implies the inhibition of the extracellular signal-regulated kinase pathway by J2 and J16.

Is the use of a potassium nitrate dentifrice effective in reducing tooth sensitivity related to in-office bleaching? A randomized triple-blind clinical trial.

OBJECTIVE: The aims of this study were to evaluate whether the use of a dentifrice containing 5% potassium nitrate (KNO3 ) prior to and during in-office dental bleaching reduces bleaching-induced tooth sensitivity and affects bleaching efficiency. MATERIALS AND METHODS: Thirty-eight individuals were randomly distributed into two groups (n = 19). The experimental group performed toothbrushing using a dentifrice containing 5% KNO3 , one week before treatment and before the first and second bleaching sessions. In the control group, a placebo dentifrice without KNO3 was applied as described for the first group. Tooth sensitivity was recorded on visual analog scales (VAS) and numeric rating scales (NRS) immediately and up to 48 h after bleaching sessions. Color change at different time intervals, was evaluated with shade guide units (∆SGU) and a digital spectrophotometer (∆E CIELab 1976 and CIEDE2000) at baseline and 7, 15, and 30 days post-bleaching. Mann-Whitney test and t-test were used to evaluate TS intensity for NRS and VAS scales, respectively, and T-test was used for color difference evaluation. RESULTS: No significant difference in tooth sensitivity's absolute risk and intensity were observed between tested groups in any evaluated treatment time for NRS (p = 0.91) or VAS scales (p = 0.48). T-test showed no significant difference in both ∆E and ∆SGU tooth color among the experimental and control groups during the different evaluation times (p = 0.27). CONCLUSION: The use of a dentifrice containing 5% KNO3 does not prevent post-operatory tooth sensitivity but allows the same whitening efficiency as a regular dentifrice. CLINICAL SIGNIFICANCE: The use of a dentifrice-containing KNO3 did not prevent bleaching-induced tooth sensitivity when high-concentrated hydrogen peroxide was used for in-office bleaching.

Mycobacterial RNA polymerase forms unstable open promoter complexes that are stabilized by CarD.

Escherichia coli has served as the archetypal organism on which the overwhelming majority of biochemical characterizations of bacterial RNA polymerase (RNAP) have been focused; the properties of E. coli RNAP have been accepted as generally representative for all bacterial RNAPs. Here, we directly compare the initiation properties of a mycobacterial transcription system with E. coli RNAP on two different promoters. The detailed characterizations include abortive transcription assays, RNAP/promoter complex stability assays and DNAse I and KMnO4 footprinting. Based on footprinting, we find that promoter complexes formed by E. coli and mycobacterial RNAPs use very similar protein/DNA interactions and generate the same transcription bubbles. However, we find that the open promoter complexes formed by E. coli RNAP on the two promoters tested are highly stable and essentially irreversible (with lifetimes much greater than 1 h), while the open promoter complexes on the same two promoters formed by mycobacterial RNAP are very unstable (lifetimes of about 2 min or less) and readily reversible. We show here that CarD, an essential mycobacterial transcription activator that is not found in E. coli, stabilizes the mycobacterial RNAP/open promoter complexes considerably by preventing transcription bubble collapse.

Structure and function of CarD, an essential mycobacterial transcription factor.

CarD, an essential transcription regulator in Mycobacterium tuberculosis, directly interacts with the RNA polymerase (RNAP). We used a combination of in vivo and in vitro approaches to establish that CarD is a global regulator that stimulates the formation of RNAP-holoenzyme open promoter (RPo) complexes. We determined the X-ray crystal structure of Thermus thermophilus CarD, allowing us to generate a structural model of the CarD/RPo complex. On the basis of our structural and functional analyses, we propose that CarD functions by forming protein/protein and protein/DNA interactions that bridge the RNAP to the promoter DNA. CarD appears poised to interact with a DNA structure uniquely presented by the RPo: the splayed minor groove at the double-stranded/single-stranded DNA junction at the upstream edge of the transcription bubble. Thus, CarD uses an unusual mechanism for regulating transcription, sensing the DNA conformation where transcription bubble formation initiates.

The far extracellular CUB domain of the adhesion GPCR ADGRG6/GPR126 is a key regulator of receptor signaling.

Adhesion G Protein-coupled receptors (aGPCRs) transduce extracellular adhesion signals into cytoplasmic signaling pathways. ADGRG6/GPR126 is an aGPCR critical for axon myelination, heart development and ear development; and is associated with developmental diseases and cancers. ADGRG6 has a large, alternatively-spliced, five-domain extracellular region (ECR) that samples different conformations and regulates receptor signaling. However, the molecular details of how the ECR regulates signaling are unclear. Herein, we studied the conformational dynamics of the conserved CUB domain which is located at the distal N-terminus of the ECR and is deleted in an alternatively-spliced isoform ( Δ CUB). We showed that the Δ CUB isoform has decreased signaling. Molecular dynamics simulations suggest that the CUB domain is involved in interdomain contacts to maintain a compact ECR conformation. A cancer-associated CUB domain mutant, C94Y, drastically perturbs the ECR conformation and results in elevated signaling, whereas another CUB mutant, Y96A, located near a conserved Ca 2+ -binding site, decreases signaling. Our results suggest an ECR-mediated mechanism for ADGRG6 regulation in which the CUB domain instructs conformational changes within the ECR to regulate receptor signaling.

Structural analysis and conformational dynamics of a holo-adhesion GPCR reveal interplay between extracellular and transmembrane domains.

Adhesion G Protein-Coupled Receptors (aGPCRs) are key cell-adhesion molecules involved in numerous physiological functions. aGPCRs have large multi-domain extracellular regions (ECR) containing a conserved GAIN domain that precedes their seven-pass transmembrane domain (7TM). Ligand binding and mechanical force applied on the ECR regulate receptor function. However, how the ECR communicates with the 7TM remains elusive, because the relative orientation and dynamics of the ECR and 7TM within a holoreceptor is unclear. Here, we describe the cryo-EM reconstruction of an aGPCR, Latrophilin3/ADGRL3, and reveal that the GAIN domain adopts a parallel orientation to the membrane and has constrained movement. Single-molecule FRET experiments unveil three slow-exchanging FRET states of the ECR relative to the 7TM within the holoreceptor. GAIN-targeted antibodies, and cancer-associated mutations at the GAIN-7TM interface, alter FRET states, cryo-EM conformations, and receptor signaling. Altogether, this data demonstrates conformational and functional coupling between the ECR and 7TM, suggesting an ECR-mediated mechanism of aGPCR activation.

Effectiveness of Lemon Verbena (Cymbopogon citratus) in Oral Candidiasis: A Systematic Review.

The rise of phytotherapy has enabled the utilization of various plant species for medicinal purposes, such as Cymbopogon citratus (C. citratus), providing solutions for oral pathologies, such as oral candidiasis. The PubMed, Web of Science, Scopus, and SciELO databases were searched. In vivo and in vitro studies on the action of C. citratus against oral candidiasis were included, and ROBINS-I was used to determine study quality and risk of bias. The search yielded 1922 articles, of which 10 met the inclusion criteria. Limited scientific evidence exists regarding the use of C. citratus for oral candidiasis. However, studies have indicated its potent antifungal effects. Further studies, preferably clinical trials, are necessary to confirm this effect and to enable its clinical use as a therapeutic option.

Posttraumatic Stress Disorder After Spontaneous Coronary Artery Dissection: A Report of the International Spontaneous Coronary Artery Dissection Registry.

BACKGROUND: Myocardial infarction secondary to spontaneous coronary artery dissection (SCAD) can be traumatic and potentially trigger posttraumatic stress disorder (PTSD). In a large, multicenter, registry-based cohort, we documented prevalence of lifetime and past-month SCAD-induced PTSD, as well as related treatment seeking, and examined a range of health-relevant correlates of SCAD-induced PTSD. METHODS AND RESULTS: Patients with SCAD were enrolled in the iSCAD (International SCAD) Registry. At baseline, site investigators completed medical report forms, and patients reported demographics, medical/SCAD history, psychosocial factors (including SCAD-induced PTSD symptoms), health behaviors, and health status via online questionnaires. Of 1156 registry patients, 859 patients (93.9% women; mean age, 52.3 years) completed questionnaires querying SCAD-induced PTSD. Nearly 35% (n=298) of patients met diagnostic criteria for probable SCAD-induced PTSD in their lifetime, and 6.4% (n=55) met criteria for probable past-month PTSD. Of 811 patients ever reporting any SCAD-induced PTSD symptoms, 34.8% indicated seeking treatment for this distress. However, 46.0% of the 298 patients with lifetime probable SCAD-induced PTSD diagnoses reported never receiving trauma-related treatment. Younger age at first SCAD, fewer years since SCAD, being single, unemployed status, more lifetime trauma, and history of anxiety were associated with greater past-month PTSD symptom severity in multivariable regression models. Greater past-month SCAD-induced PTSD symptoms were associated with greater past-week sleep disturbance and worse past-month disease-specific health status when adjusting for various risk factors. CONCLUSIONS: Given the high prevalence of SCAD-induced PTSD symptoms, efforts to support screening for these symptoms and connecting patients experiencing distress with empirically supported treatments are critical next steps. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04496687.

Drugs Prescribed for Asthma and Their Adverse Effects on Dental Health.

Asthma is a chronic, heterogeneous respiratory pathology characterized by reversible airway inflammation. Therapeutics focus on symptom reduction and control, aimed at preserving normal pulmonary function and inducing bronchodilatation. The objective of this review is to describe the adverse effects produced by anti-asthmatic drugs on dental health, according to the reported scientific evidence. A bibliographic review was carried out on databases, such as Web of science, Scopus, and ScienceDirect. Most anti-asthmatic medications are administered using inhalers or nebulizers, making it impossible to avoid contact of the drug with hard dental tissues and oral mucosa, and thus promoting a greater risk of oral alterations, mainly due to decreases in the salivary flow and pH. Such changes can cause diseases, such as dental caries, dental erosion, tooth loss, periodontal disease, bone resorption, as well as fungal infections, such as oral candidiasis.

Isoform- and ligand-specific modulation of the adhesion GPCR ADGRL3/Latrophilin3 by a synthetic binder.

Adhesion G protein-coupled receptors (aGPCRs) are cell-surface proteins with large extracellular regions that bind to multiple ligands to regulate key biological functions including neurodevelopment and organogenesis. Modulating a single function of a specific aGPCR isoform while affecting no other function and no other receptor is not trivial. Here, we engineered an antibody, termed LK30, that binds to the extracellular region of the aGPCR ADGRL3, and specifically acts as an agonist for ADGRL3 but not for its isoform, ADGRL1. The LK30/ADGRL3 complex structure revealed that the LK30 binding site on ADGRL3 overlaps with the binding site for an ADGRL3 ligand - teneurin. In cellular-adhesion assays, LK30 specifically broke the trans-cellular interaction of ADGRL3 with teneurin, but not with another ADGRL3 ligand - FLRT3. Our work provides proof of concept for the modulation of isoform- and ligand-specific aGPCR functions using unique tools, and thus establishes a foundation for the development of fine-tuned aGPCR-targeted therapeutics.

Distribution of Dental Fluorosis in the Southern Zone of Ecuador: An Epidemiological Study.

In recent decades, the increase in fluoride exposure has raised the numbers of dental fluorosis in fluoridated and non-fluoridated communities In Ecuador, but the last national epidemiological study on DF was conducted more than a decade ago. The objective of this cross-sectional descriptive study was to determine the prevalence, distribution and severity of dental fluorosis (DF) using the Dean index in 1606 schoolchildren aged 6 to 12 years from urban and rural environments in provinces that make up the Southern Region of Ecuador. Participants met the inclusion criteria which were age, locality, informed consent document and no legal impediment. The results are presented using percentage frequency measures and chi-square associations. The prevalence of dental fluorosis was 50.1% in the areas of Azuay, Cañar and Morona Santiago, with no significant differences (x2 = 5.83, p = 0.054). The types of DF found most frequently were very mild and mild in all provinces; a moderate degree was more prevalent in Cañar (17%). There was no significant association (p > 0.05) between sex and the presence of dental fluorosis and, with respect to severity, the most frequent degree was moderate at the age of 12 years. The prevalence of dental fluorosis in the area evaluated is high, especially in the light and very light degrees, with a tendency toward moderate levels. It is necessary to carry out studies on the factors that are predisposing to the development of this pathology in the population studied. This research is an update regarding this pathology in Ecuador, so it is concluded that it is necessary to continue developing studies based on the findings obtained, thus contributing to the public health of the country.

Younger Age Impacts Perceptions of Care Received in the Emergency Department Among Women with Spontaneous Coronary Artery Dissection.

Background: Spontaneous coronary artery dissection (SCAD) is a nonatherosclerotic etiology of acute coronary syndrome (ACS) that primarily affects younger women with few traditional cardiovascular disease risk factors. The primary objective of this study was to evaluate how younger age impacts the perception of care women receive in the emergency department (ED) at the time of their first or only SCAD. Methods: SCAD survivors were recruited using SCAD Alliance social media platforms to complete a one-time online survey regarding their experiences of seeking treatment for SCAD in the ED and their post-SCAD recovery. A total of 409 participants consented to participate in the parent study and data collected from the 367 participants who reported female gender were further analyzed. Results: Fewer participants <50 years old than would be expected under the null hypothesis (i.e., 65.5% observed vs. 71.2% expected, p = 0.009) reported perceived serious treatment by ED staff, more participants <50 years than would be expected under the null hypothesis (i.e., 12.0% observed vs. 9.3% expected, p = 0.049) reported perceived dismissive treatment by ED staff, and more participants <50 years than would be expected under the null hypothesis (i.e., 13.3% observed vs. 10.8% expected, p = 0.02) reported discharge from the ED without a diagnosis. Conclusions: Results of this study highlight the different experiences of younger SCAD survivors' engaging with providers in the ED. Further research regarding strategies for increasing ED providers' clinical interrogation of SCAD when treating and evaluating younger female patients presenting with ACS symptoms is indicated.

Phytotherapy: A Solution to Decrease Antifungal Resistance in the Dental Field.

The pathologies produced by fungi in the oral cavity in recent decades have become a health problem, with factors such as an imbalance of the local microbiota being the cause for their propagation. Conventional antifungal treatments, instead of being beneficial, have generated alterations that have led to antifungal resistance. The aim of this study was to investigate and describe phytotherapy resources as a possible solution to oral antifungal resistance. A bibliographic search was carried out on platforms such as PubMed, Scopus, ScienceDirect, Web of Science, and Google scholar. A total of 248 scientific articles were obtained, of which 108 met the inclusion criteria. Microorganisms of fungal origin currently show resistance to the different antifungals of conventional use, which is undoubtedly altering the oral health of human beings, but there are new therapeutic possibilities such as the active principles of various natural species.

Prevalence of Caries According to the ICDAS II in Children from 6 and 12 Years of Age from Southern Ecuadorian Regions.

In Ecuador, national data on dental caries are scarce and the detection of incipient enamel lesions has been omitted. The objective of this study was to determine the prevalence of caries in school children aged 6 and 12 years of both sexes, belonging to urban and rural areas of three provinces of the country, using the International Caries Detection and Assessment System (ICDAS II). The sample consisted of 665 children from public schools, examined according to ICDASII. Caries prevalence and caries index were established using ICDAS II 2-6/C-G and ICDAS II 4-6/E-G criteria for comparison with WHO indicators. The Mann−Whitney U statistical test was used for comparison of two groups, the effect size was measured with the correlation coefficient. and the Kruskal−Wallis H test (p < 0.05) for multiple comparisons. Caries prevalence exceeded 87% for primary and permanent dentition. There were no significant differences according to province (p ≤ 0.05). The caries index at 6 years was 6.57 and at 12 years 9.21. The SIC was high at 12 years in rural areas. The prevalence of caries in the population studied was high despite the preventive measures established by health agencies.

Ambulatory Sedation for Dental Procedures-Case of Cuenca, Ecuador.

In recent years, the dental treatment of children under sedation and/or general anesthesia on an outpatient basis has been developed as a behavioral management model in pediatric dentistry. The objective of this study was to establish the percentage of pediatric patients who required deep sedation on an outpatient basis in dental offices in the city of Cuenca, Ecuador. An observational study was conducted with a sample of 450 records of school- and preschool-age patients, where the variables were type and time of treatment, age, and sex. Statistical data were analyzed using the statistical program SPSS V.27 (IBM, Armonk, NY, USA). The highest percentage of children who received sedation were of preschool age. In general, there were three types of procedures per session, the most frequent being restorations (67%), followed by pulp treatment (49.8%) and, less frequently, minor surgery. The need for sedation for dental procedures is high in preschool patients, and ambulatory sedation has contributed to meeting this need. However, a regulation for its use is required at a national level.