ABSTRACT
Strategies to increase the efficacy and/or expand the spectrum of activity of existing antibiotics provide a potentially fast path to clinically address the growing crisis of antibiotic-resistant infections. Here, we report the synthesis, antibacterial efficacy, and mechanistic activity of an unprecedented class of biguanide-antibiotic conjugates. Our lead biguanide-vancomycin conjugate, V-C6-Bg-PhCl (5e), induces highly effective cell killing with up to a 2 orders-of-magnitude improvement over its parent compound, vancomycin (V), against vancomycin-resistant enterococcus. V-C6-Bg-PhCl (5e) also exhibits improved activity against mycobacteria and each of the ESKAPE pathogens, including the Gram-negative organisms. Furthermore, we uncover broad-spectrum killing activity against biofilm-associated Gram-positive and Gram-negative bacteria as well as mycobacteria not observed for clinically used antibiotics such as oritavancin. Mode-of-action studies reveal that vancomycin-like cell wall synthesis inhibition with improved efficacy attributed to enhanced engagement at vancomycin binding sites through biguanide association with relevant cell-surface anions for Gram-positive and Gram-negative bacteria. Due to its potency, remarkably broad activity, and lack of acute mammalian cell toxicity, V-C6-Bg-PhCl (5e) is a promising candidate for treating antibiotic-resistant infections and notoriously difficult-to-treat slowly growing and antibiotic-tolerant bacteria associated with chronic and often incurable infections. More generally, this study offers a new strategy (biguanidinylation) to enhance antibiotic activity and facilitate clinical entry.
Subject(s)
Anti-Bacterial Agents , Biguanides , Biofilms , Gram-Negative Bacteria , Gram-Positive Bacteria , Microbial Sensitivity Tests , Vancomycin , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/chemical synthesis , Biofilms/drug effects , Vancomycin/pharmacology , Vancomycin/chemistry , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Biguanides/pharmacology , Biguanides/chemistry , Biguanides/chemical synthesis , Mycobacterium/drug effects , Molecular StructureABSTRACT
Significance: Widefield microscopy of the entire dorsal part of mouse cerebral cortex enables large-scale ("mesoscopic") imaging of different aspects of neuronal activity with spectrally compatible fluorescent indicators as well as hemodynamics via oxy- and deoxyhemoglobin absorption. Versatile and cost-effective imaging systems are needed for large-scale, color-multiplexed imaging of multiple fluorescent and intrinsic contrasts. Aim: We aim to develop a system for mesoscopic imaging of two fluorescent and two reflectance channels. Approach: Excitation of red and green fluorescence is achieved through epi-illumination. Hemoglobin absorption imaging is achieved using 525- and 625-nm light-emitting diodes positioned around the objective lens. An aluminum hemisphere placed between objective and cranial window provides diffuse illumination of the brain. Signals are recorded sequentially by a single sCMOS detector. Results: We demonstrate the performance of our imaging system by recording large-scale spontaneous and stimulus-evoked neuronal, cholinergic, and hemodynamic activity in awake, head-fixed mice with a curved "crystal skull" window expressing the red calcium indicator jRGECO1a and the green acetylcholine sensor GRAB ACh 3.0 . Shielding of illumination light through the aluminum hemisphere enables concurrent recording of pupil diameter changes. Conclusions: Our widefield microscope design with a single camera can be used to acquire multiple aspects of brain physiology and is compatible with behavioral readouts of pupil diameter.
ABSTRACT
The delivery of oligonucleotides across biological barriers is a challenge of unsurpassed significance at the interface of materials science and medicine, with emerging clinical utility in prophylactic and therapeutic vaccinations, immunotherapies, genome editing, and cell rejuvenation. Here, we address the role of readily available branched lipids in the design, synthesis, and evaluation of isoprenoid charge-altering releasable transporters (CARTs), a pH-responsive oligomeric nanoparticle delivery system for RNA. Systematic variation of the lipid block reveals an emergent relationship between the lipid block and the neutralization kinetics of the polycationic block. Unexpectedly, iA21A11, a CART with the smallest lipid side chain, isoamyl-, was identified as the lead isoprenoid CART for the in vitro transfection of immortalized lymphoblastic cell lines. When administered intramuscularly in a murine model, iA21A11-mRNA complexes induce higher protein expression levels than our previous lead CART, ONA. Isoprenoid CARTs represent a new delivery platform for RNA vaccines and other polyanion-based therapeutics.
Subject(s)
Lipids , RNA, Messenger , Animals , Mice , RNA, Messenger/genetics , Lipids/chemistry , Humans , Terpenes/chemistry , Archaea/genetics , Archaea/chemistry , Nanoparticles/chemistryABSTRACT
The global challenge of antibiotic resistance necessitates the introduction of more effective antibiotics. Here we report a potentially general design strategy, exemplified with vancomycin, that improves and expands antibiotic performance. Vancomycin is one of the most important antibiotics in use today for the treatment of Gram-positive infections. However, it fails to eradicate difficult-to-treat biofilm populations. Vancomycin is also ineffective in killing Gram-negative bacteria due to its inability to breach the outer membrane. Inspired by our seminal studies on cell penetrating guanidinium-rich transporters (e.g., octaarginine), we recently introduced vancomycin conjugates that effectively eradicate Gram-positive biofilm bacteria, persister cells and vancomycin-resistant enterococci (with V-r8, vancomycin-octaarginine), and Gram-negative pathogens (with V-R, vancomycin-arginine). Having shown previously that the spatial array (linear versus dendrimeric) of multiple guanidinium groups affects cell permeation, we report here for the first time vancomycin conjugates with dendrimerically displayed guanidinium groups that exhibit superior efficacy and breadth, presenting the best activity of V-r8 and V-R in single broad-spectrum compounds active against ESKAPE pathogens. Mode-of-action studies reveal cell-surface activity and enhanced vancomycin-like killing. The vancomycin-polyguanidino dendrimer conjugates exhibit no acute mammalian cell toxicity or hemolytic activity. Our study introduces a new class of broad-spectrum vancomycin derivatives and a general strategy to improve or expand antibiotic performance through combined mode-of-action and function-oriented design studies.
Subject(s)
Anti-Bacterial Agents , Methicillin-Resistant Staphylococcus aureus , Animals , Anti-Bacterial Agents/pharmacology , Biofilms , Gram-Negative Bacteria , Gram-Positive Bacteria , Guanidine/pharmacology , Mammals , Staphylococcus aureus , Vancomycin/pharmacologyABSTRACT
SIGNIFICANCE: Widefield microscopy of the entire dorsal part of mouse cerebral cortex enables large-scale (mesoscopic) imaging of neuronal activity with fluorescent indicators as well as hemodynamics via oxy- and deoxyhemoglobin absorption. Versatile and cost-effective imaging systems are needed for large-scale, color-multiplexed imaging of multiple fluorescent and intrinsic contrasts. AIM: Develop a system for mesoscopic imaging of two fluorescent and two reflectance channels. APPROACH: Excitation of red and green fluorescence is achieved through epi-illumination. Hemoglobin absorption imaging is achieved using 525- and 625nm LEDs positioned around the objective lens. An aluminum hemisphere placed between objective and cranial window provides diffuse illumination of the brain. Signals are recorded sequentially by a single sCMOS detector. RESULTS: We demonstrate performance of our imaging system by recording large-scale spontaneous and stimulus-evoked neuronal, cholinergic, and hemodynamic activity in awake head-fixed mice with a curved crystal skull window expressing the red calcium indicator jRGECO1a and the green acetylcholine sensor GRABACh3.0 . Shielding of illumination light through the aluminum hemisphere enables concurrent recording of pupil diameter changes. CONCLUSIONS: Our widefield microscope design with single camera can be used to acquire multiple aspects of brain physiology and is compatible with behavioral readouts of pupil diameter.
ABSTRACT
BACKGROUND: Mohs micrographic surgery may be discontinued with positive margins as an anticipated strategy for multidisciplinary care or as an unanticipated occurrence. Management of primary tumors has not been compared after anticipated versus unanticipated incomplete Mohs micrographic surgery (iMMS). OBJECTIVE: To compare rates and timing of adjuvant surgery after iMMS and final margin status when iMMS is anticipated versus unanticipated. Secondary outcomes were preoperative and intraoperative clinicopathologic factors associated with iMMS. METHODS: Cases of iMMS of keratinocyte carcinomas at a tertiary academic center between 2005 and 2022 were classified as anticipated (preoperative assembly of multidisciplinary teams) or unanticipated (ad hoc management of positive margins). Rate, timing, and final margin status of adjuvant surgery was compared between anticipated and unanticipated iMMS cohorts using χ2/Fisher exact test for categorical variables and t-test for continuous variables. RESULTS: Of 127 iMMS cases, 51.2% (65/127) were anticipated. Anticipated iMMS cases were more likely to undergo additional resection (98.5% vs 72.6%, p < .001), with fewer delays (3.9 vs 13.2 days, p < .001) and higher rates of final margin clearance (84.6% vs 59.7%, p < .001). CONCLUSION: When iMMS is anticipated as part of multidisciplinary care, patients are more likely to undergo additional resection, with fewer delays to next surgery and higher final margin clearance rates.
Subject(s)
Carcinoma, Basal Cell , Skin Neoplasms , Humans , Skin Neoplasms/surgery , Skin Neoplasms/pathology , Mohs Surgery , Time-to-Treatment , Treatment Outcome , Carcinoma, Basal Cell/surgery , Carcinoma, Basal Cell/pathology , Margins of Excision , Retrospective StudiesABSTRACT
BACKGROUND: The autonomic response to transcutaneous auricular vagus nerve stimulation (taVNS) has been linked to the engagement of brainstem circuitry modulating autonomic outflow. However, the physiological mechanisms supporting such efferent vagal responses are not well understood, particularly in humans. HYPOTHESIS: We present a paradigm for estimating directional brain-heart interactions in response to taVNS. We propose that our approach is able to identify causal links between the activity of brainstem nuclei involved in autonomic control and cardiovagal outflow. METHODS: We adopt an approach based on a recent reformulation of Granger causality that includes permutation-based, nonparametric statistics. The method is applied to ultrahigh field (7T) functional magnetic resonance imaging (fMRI) data collected on healthy subjects during taVNS. RESULTS: Our framework identified taVNS-evoked functional brainstem responses with superior sensitivity compared to prior conventional approaches, confirming causal links between taVNS stimulation and fMRI response in the nucleus tractus solitarii (NTS). Furthermore, our causal approach elucidated potential mechanisms by which information is relayed between brainstem nuclei and cardiovagal, i.e., high-frequency heart rate variability, in response to taVNS. Our findings revealed that key brainstem nuclei, known from animal models to be involved in cardiovascular control, exert a causal influence on taVNS-induced cardiovagal outflow in humans. CONCLUSION: Our causal approach allowed us to noninvasively evaluate directional interactions between fMRI BOLD signals from brainstem nuclei and cardiovagal outflow.
Subject(s)
Transcutaneous Electric Nerve Stimulation , Vagus Nerve Stimulation , Animals , Humans , Vagus Nerve Stimulation/methods , Brain Stem/diagnostic imaging , Brain Stem/physiology , Transcutaneous Electric Nerve Stimulation/methods , Vagus Nerve/physiology , Solitary NucleusABSTRACT
BACKGROUND: Regulatory T cells (Tregs) are protective in atherosclerosis but reduced during disease progression due to cell death and loss of stability. However, the mechanisms of Treg dysfunction remain unknown. Oxidized phospholipids are abundant in atherosclerosis and can activate innate immune cells, but little is known regarding their impact on T cells. Given Treg loss during atherosclerosis progression and oxidized phospholipid levels in the plaque microenvironment, we investigated whether oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (oxPAPC), an oxidized phospholipid associated with atherosclerotic plaques, alters Treg differentiation and function. METHODS: CD4+ T cells were polarized to Treg, T helper (Th) 1, and Th17 cells with or without oxPAPC and assessed by flow cytometry. Gene expression in oxPAPC-treated Tregs was analyzed by bulk RNA sequencing. Functional studies of oxPAPC-induced Tregs were performed by coculturing Tregs with CellTrace Violet-labeled cells in vitro, and by adoptively transferring Tregs to hyperlipidemic Ldlr-/- mice to measure atherosclerosis progression. RESULTS: Compared with controls, oxPAPC-treated Tregs were less viable, but surviving cells expressed higher levels of the Th1-associated markers T-bet, CXCR3, and IFN (interferon)-γ. Th1 and Th17 skewing cultures were unaltered by oxPAPC. IFN-γ is linked to Treg instability, thus Treg polarization experiments were repeated using Ifngr1-/- CD4+ T cells. IFNγR1 (INF gamma receptor 1) deficiency did not improve cell viability in oxPAPC-treated Tregs; however, T-bet and IFN-γ expression was not increased in surviving cells suggesting a role for IFN-γsignaling. OxPAPC-treated Tregs were less suppressive in vitro, and adoptive transfer studies in hyperlipidemic Ldlr-/- mice showed that oxPAPC-induced Tregs possessed altered tissue homing and were insufficient to inhibit atherosclerosis progression. CONCLUSIONS: OxPAPC elicits Treg-specific changes altering Treg differentiation and inducing a Th1-like phenotype in surviving cells partially through IFN-γ signaling. This is biologically relevant as oxPAPC-treated Tregs do not reduce atherosclerosis progression in Ldlr-/- mice. This study supports the role of oxidized phospholipids in negatively impacting Treg differentiation and atheroprotective function.
Subject(s)
Atherosclerosis , Phospholipids , Mice , Animals , Phospholipids/metabolism , T-Lymphocytes, Regulatory , Interferon-gamma/metabolism , Atherosclerosis/genetics , Atherosclerosis/prevention & control , Cell DifferentiationABSTRACT
Background: Policymakers and payers are reevaluating the temporary telehealth flexibilities granted during the COVID-19 public health emergency, which will shape future teledermatology utilization. Objective: To summarize the recently expanded telehealth flexibilities in the United States, projected changes, and corresponding implications for dermatologists. Methods: Narrative review of the literature, United States policies and regulations, and white paper reports. Results: Key telehealth flexibilities included expansion of payment parity, relaxation of originating site requirements, loosening of state licensure requirements, and HIPAA (Health Insurance Portability and Accountability Act of 1996) enforcement discretion. These changes enabled widespread accessibility and adoption of teledermatology, which enhanced high-quality and cost-effective dermatologic care. Most waivers will end 151 days following the end of the public health emergency declaration. Notably, asynchronous telehealth was not included in the reimbursement expansion. Limitations: Only policies and regulations through December 2022 are included. Conclusion: It will be important for the field of dermatology to stay abreast of the upcoming changes in telemedicine policies and reimbursement, to demonstrate teledermatology's value through evidence-based studies and to advocate for enduring policies that will promote the accessibility of teledermatology for patients.
ABSTRACT
BACKGROUND AND AIMS: Hybridization is increasingly recognized as an integral part of the dynamics of species range expansion and contraction. Thus, it is important to understand the reproductive barriers between co-occurring species. Extending previous studies that argued that the rare Eucalyptus risdonii was expanding into the range of the surrounding E. amygdalina by both seed and pollen dispersal, we here investigate the long-term fitness of both species and their hybrids and whether expansion is continuing. METHODS: We assessed the survival of phenotypes representing a continuum between the two pure species in a natural hybrid swarm after 29 years, along with seedling recruitment. The performance of pure species as well as of artificial and natural hybrids was also assessed over 28 years in a common garden trial. KEY RESULTS: In the hybrid zone, E. amygdalina adults showed greater mortality than E. risdonii, and the current seedling cohort is still dominated by E. risdonii phenotypes. Morphologically intermediate individuals appeared to be the least fit. Similar results were observed after growing artificial first-generation and natural hybrids alongside pure species families in a common garden trial. Here, the survival, reproduction, health and growth of the intermediate hybrids were significantly less than those of either pure species, consistent with hybrid inferiority, although this did not manifest until later reproductive ages. Among the variable progeny of natural intermediate hybrids, the most E. risdonii-like phenotypes were the most fit. CONCLUSIONS: This study contributes to the increasing number of reports of hybrid inferiority in Eucalyptus, suggesting that post-zygotic barriers contribute to the maintenance of species integrity even between closely related species. However, with fitness rapidly recovered following backcrossing, it is argued that hybridization can still be an important evolutionary process, in the present case appearing to contribute to the range expansion of the rare E. risdonii in response to climate change.
Subject(s)
Eucalyptus , Biological Evolution , Climate Change , Eucalyptus/genetics , Hybridization, Genetic , ReproductionABSTRACT
Dopamine has direct and complex vasoactive effects on cerebral circulation. Catechol-O-methyltransferase (COMT) regulates cortical dopamine, and its activity can be influenced both genetically and pharmacologically. COMT activity influences the functional connectivity of the PFC at rest, as well as its activity during task performance, determined using blood oxygen level-dependent (BOLD) fMRI. However, its effects on cerebral perfusion have been relatively unexplored. Here, 76 healthy males, homozygous for the functional COMT Val158Met polymorphism, were administered either the COMT inhibitor tolcapone or placebo in a double-blind, randomised design. We then assessed regional cerebral blood flow at rest using pulsed arterial spin labelling. Perfusion was affected by both genotype and drug. COMT genotype affected frontal regions (Val158 > Met158), whilst tolcapone influenced parietal and temporal regions (placebo > tolcapone). There was no genotype by drug interaction. Our data demonstrate that lower COMT activity is associated with lower cerebral blood flow, although the regions affected differ between those affected by genotype compared with those altered by acute pharmacological inhibition. The results extend the evidence for dopaminergic modulation of cerebral blood flow. Our findings also highlight the importance of considering vascular effects in functional neuroimaging studies, and of exercising caution in ascribing group differences in BOLD signal solely to altered neuronal activity if information about regional perfusion is not available.
Subject(s)
Catechol O-Methyltransferase Inhibitors/pharmacology , Catechol O-Methyltransferase/metabolism , Cerebrovascular Circulation/physiology , Magnetic Resonance Imaging/methods , Perfusion Imaging/methods , Spin Labels , Adolescent , Adult , Cerebrovascular Circulation/drug effects , Dopamine/metabolism , Humans , Male , Tolcapone/pharmacology , Young AdultSubject(s)
Melanoma , Skin Neoplasms , Suicide , Death , Humans , Incidence , Marital Status , Patients , Prognosis , Risk Factors , SkinABSTRACT
Due to climate change-induced alterations of temperature and humidity, the distribution of pathogen-carrying organisms such as ticks may shift. Tick survival is often limited by environmental factors such as dryness, but a predicted hotter and wetter world may allow the expansion of tick ranges. Dermacentor andersoni and D. variabilis ticks are morphologically similar, co-occur throughout the Inland Northwest of Washington State, U.S.A., and both can be injected with pathogenic Rickettsia and Francisella bacteria. Differences in behavior and the potential role of endosymbiotic Rickettsia and Francisella in these ticks are poorly studied. We wanted to measure behavioral and ecological differences between the two species and determine which, if any, Rickettsia and Francisella bacteria - pathogenic or endosymbiotic - they carried. Additionally, we wanted to determine if either tick species may be selected for if the climate in eastern Washington becomes wetter or dryer. We found that D. andersoni is more resistant to desiccation, but both species share similar questing behaviors such as climbing and attraction to bright light. Both also avoid the odor of eucalyptus and DEET but not permethrin. Although both tick species are capable of transmitting pathogenic species of Francisella and Rickettsia, which cause tularemia and Rocky Mountain Spotted Fever, respectively, we found primarily non-pathogenic endosymbiotic strains of Francisella and Rickettsia, and only one tick infected with F. tularensis subspecies holarctica.
Subject(s)
Arachnid Vectors/physiology , Behavior, Animal , Dermacentor/physiology , Francisella/isolation & purification , Rickettsia/isolation & purification , Animals , Arachnid Vectors/microbiology , Dermacentor/microbiology , Female , Male , Rocky Mountain Spotted Fever/transmission , Symbiosis , Tularemia/transmission , WashingtonABSTRACT
Hidrocystomas are benign cysts of sweat duct epithelium that can present as single or multiple lesions, with or without pigmentation. The size is typically 1-3mm in diameter. Although hidrocystomas commonly occur in most parts of the head and neck region, occurrence on the scalp is rare. Herein, we present a 29-year-old woman with a giant pigmented apocrine hidrocystoma of the scalp, which, to our knowledge, represents the largest of its kind reported to date.