Gene correction presents one of few options for a cure for all patients with cystic fibrosis. This commentary discusses new applications of CRISPR-based gene editing technology with increased ...efficiency and specificity to correct the cystic fibrosis transmembrane regulator (CFTR) function in patient-specific primary epithelial cells.
Key points
The development of age‐related arterial endothelial dysfunction, a key antecedent of increased cardiovascular disease (CVD) risk, is mediated largely by reduced nitric oxide ...bioavailability as a consequence of oxidative stress.
Mitochondria are critical signalling organelles in the vasculature, which, when dysregulated, become a source of excessive reactive oxygen species; the role of mitochondria‐derived oxidative stress in age‐related vascular dysfunction is unknown.
We show that a mitochondria‐targeted antioxidant, MitoQ, ameliorates vascular endothelial dysfunction in old mice and that these improvements are associated with the normalization of mitochondria‐derived oxidative stress and markers of arterial mitochondrial health.
These results indicate that mitochondria‐derived oxidative stress is an important mechanism underlying the development of age‐related vascular endothelial dysfunction and therefore may be a promising therapeutic target.
Mitochondria‐targeted antioxidants represent a novel strategy for preserving healthy vascular endothelial function in primary ageing and preventing age‐related CVD in humans.
Age‐related arterial endothelial dysfunction, a key antecedent of the development of cardiovascular disease (CVD), is largely caused by a reduction in nitric oxide (NO) bioavailability as a consequence of oxidative stress. Mitochondria are a major source and target of vascular oxidative stress when dysregulated. Mitochondrial dysregulation is associated with primary ageing, but its role in age‐related endothelial dysfunction is unknown. Our aim was to determine the efficacy of a mitochondria‐targeted antioxidant, MitoQ, in ameliorating vascular endothelial dysfunction in old mice. Ex vivo carotid artery endothelium‐dependent dilation (EDD) to increasing doses of acetylcholine was impaired by ∼30% in old (∼27 months) compared with young (∼8 months) mice as a result of reduced NO bioavailability (P < 0.05). Acute (ex vivo) and chronic (4 weeks in drinking water) administration of MitoQ completely restored EDD in older mice by improving NO bioavailability. There were no effects of age or MitoQ on endothelium‐independent dilation to sodium nitroprusside. The improvements in endothelial function with MitoQ supplementation were associated with the normalization of age‐related increases in total and mitochondria‐derived arterial superoxide production and oxidative stress (nitrotyrosine abundance), as well as with increases in markers of vascular mitochondrial health, including antioxidant status. MitoQ also reversed the age‐related increase in endothelial susceptibility to acute mitochondrial damage (rotenone‐induced impairment in EDD). Our results suggest that mitochondria‐derived oxidative stress is an important mechanism underlying the development of endothelial dysfunction in primary ageing. Mitochondria‐targeted antioxidants such as MitoQ represent a promising novel strategy for the preservation of vascular endothelial function with advancing age and the prevention of age‐related CVD.
This meta‐analysis investigated the relationships between person–job (PJ), person–organization (PO), person–group, and person–supervisor fit with preentry (applicant attraction, job acceptance, ...intent to hire, job offer) and postentry individual‐level criteria (attitudes, performance, withdrawal behaviors, strain, tenure). A search of published articles, conference presentations, dissertations, and working papers yielded 172 usable studies with 836 effect sizes. Nearly all of the credibility intervals did not include 0, indicating the broad generalizability of the relationships across situations. Various ways in which fit was conceptualized and measured, as well as issues of study design, were examined as moderators to these relationships in studies of PJ and PO fit. Interrelationships between the various types of fit are also meta‐analyzed. 25 studies using polynomial regression as an analytic technique are reviewed separately, because of their unique approach to assessing fit. Broad themes emerging from the results are discussed to generate the implications for future research on fit.
The bulk properties of a copolymer are directly affected by monomer sequence, yet efficient, scalable, and controllable syntheses of sequenced copolymers remain a defining challenge in polymer ...science. We have previously demonstrated, using polymers prepared by a step-growth synthesis, that hydrolytic degradation of poly(lactic-co-glycolic acid)s is dramatically affected by sequence. While much was learned, the step-growth mechanism gave no molecular weight control, unpredictable yields, and meager scalability. Herein, we describe the synthesis of closely related sequenced polyesters prepared by entropy-driven ring-opening metathesis polymerization (ED-ROMP) of strainless macromonomers with imbedded monomer sequences of lactic, glycolic, 6-hydroxy hexanoic, and syringic acids. The incorporation of ethylene glycol and metathesis linkers facilitated synthesis and provided the olefin functionality needed for ED-ROMP. Ring-closing to prepare the cyclic macromonomers was demonstrated using both ring-closing metathesis and macrolactonization reactions. Polymerization produced macromolecules with controlled molecular weights on a multigram scale. To further enhance molecular weight control, the macromonomers were prepared with cis-olefins in the metathesis-active segment. Under these selectivity-enhanced (SEED-ROMP) conditions, first-order kinetics and narrow dispersities were observed and the effect of catalyst initiation rate on the polymerization was investigated. Enhanced living character was further demonstrated through the preparation of block copolymers. Computational analysis suggested that the enhanced polymerization kinetics were due to the cis-macrocyclic olefin being less flexible and having a larger population of metathesis-reactive conformers. Although used for polyesters in this investigation, SEED-ROMP represents a general method for incorporation of sequenced segments into molecular weight-controlled polymers.
Stem cells and lung regeneration Parekh, Kalpaj R; Nawroth, Janna; Pai, Albert ...
American Journal of Physiology: Cell Physiology,
10/2020, Letnik:
319, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The ability to replace defective cells in an airway with cells that can engraft, integrate, and restore a functional epithelium could potentially cure a number of lung diseases. Progress toward the ...development of strategies to regenerate the adult lung by either in vivo or ex vivo targeting of endogenous stem cells or pluripotent stem cell derivatives is limited by our fundamental lack of understanding of the mechanisms controlling human lung development, the precise identity and function of human lung stem and progenitor cell types, and the genetic and epigenetic control of human lung fate. In this review, we intend to discuss the known stem/progenitor cell populations, their relative differences between rodents and humans, their roles in chronic lung disease, and their therapeutic prospects. Additionally, we highlight the recent breakthroughs that have increased our understanding of these cell types. These advancements include novel lineage-traced animal models and single-cell RNA sequencing of human airway cells, which have provided critical information on the stem cell subtypes, transition states, identifying cell markers, and intricate pathways that commit a stem cell to differentiate or to maintain plasticity. As our capacity to model the human lung evolves, so will our understanding of lung regeneration and our ability to target endogenous stem cells as a therapeutic approach for lung disease.
Abstract
Dopamine (DA, 3-hydroxytyramine) is a member of the catecholamine family and is classically characterized according to its role in the central nervous system as a neurotransmitter. In recent ...decades, many novel and intriguing discoveries have been made about the peripheral expression of DA receptors (DRs) and the role of DA signaling in both normal and pathological processes. Drawing from decades of evidence suggesting a link between DA and cancer, the DA pathway has recently emerged as a potential target in antitumor therapies. Due to the onerous, expensive and frequently unsuccessful nature of drug development, the repurposing of dopaminergic drugs for cancer therapy has the potential to greatly benefit patients and drug developers alike. However, the lack of clear mechanistic data supporting the direct involvement of DRs and their downstream signaling components in cancer represents an ongoing challenge that has limited the translation of these drugs to the clinic. Despite this, the breadth of evidence linking DA to cancer and non-tumor cells in the tumor microenvironment justifies further inquiry into the potential applications of this treatment modality in cancer. Herein, we review the literature characterizing the interplay between the DA signaling axis and cancer, highlighting key findings, and then propose rational lines of investigation to follow.
Radiotherapy is a highly effective anticancer treatment forming part of the standard of care for the majority of patients, but local and distal disease recurrence remains a major cause of mortality. ...Radiotherapy is known to enhance tumor immunogenicity; however, the contribution and mechanisms of radiotherapy-induced immune responses are unknown.
The impact of low-dose fractionated radiotherapy (5 × 2 Gy) alone and in combination with αPD-1 mAb on the tumor microenvironment was evaluated by flow cytometry and next-generation sequencing of the T-cell receptor (TCR) repertoire. A dual-tumor model was used, with fractionated radiotherapy delivered to a single tumor site to enable evaluation of the local and systemic response to treatment and ability to induce abscopal responses outside the radiation field.
We show that fractionated radiotherapy leads to T-cell infiltration at the irradiated site; however, the TCR landscape remains dominated by polyclonal expansion of preexisting T-cell clones. Adaptive resistance via the PD-1/PD-L1 pathway restricts the generation of systemic anticancer immunity following radiotherapy, which can be overcome through combination with αPD-1 mAb leading to improved local and distal tumor control. Moreover, we show that effective clearance of tumor following combination therapy is dependent on both T cells resident in the tumor at the time of radiotherapy and infiltrating T cells.
These data provide evidence that radiotherapy can enhance T-cell trafficking to locally treated tumor sites and augment preexisting anticancer T-cell responses with the capacity to mediate regression of out-of-field tumor lesions when delivered in combination with αPD-1 mAb therapy.
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Recently, we developed an optimal decellularization protocol to generate 3D porcine myocardial scaffolds, which preserve the natural extracellular matrix structure, mechanical anisotropy, and ...vasculature templates and also show good cell recellularization and differentiation potential. In this study, a multistimulation bioreactor was built to provide coordinated mechanical and electrical stimulation for facilitating stem cell differentiation and cardiac construct development. The acellular myocardial scaffolds were seeded with mesenchymal stem cells (106 cells/mL) by needle injection and subjected to 5-azacytidine treatment (3 μmol/L, 24 h) and various bioreactor conditioning protocols. We found that after 2 days of culturing with mechanical (20% strain) and electrical stimulation (5 V, 1 Hz), high cell density and good cell viability were observed in the reseeded scaffold. Immunofluorescence staining demonstrated that the differentiated cells showed a cardiomyocyte-like phenotype by expressing sarcomeric α-actinin, myosin heavy chain, cardiac troponin T, connexin-43, and N-cadherin. Biaxial mechanical testing demonstrated that positive tissue remodeling took place after 2 days of bioreactor conditioning (20% strain + 5 V, 1 Hz); passive mechanical properties of the 2 day and 4 day tissue constructs were comparable to those of the tissue constructs produced by stirring reseeding followed by 2 weeks of static culturing, implying the effectiveness and efficiency of the coordinated simulations in promoting tissue remodeling. In short, the synergistic stimulations might be beneficial not only for the quality of cardiac construct development but also for patients by reducing the waiting time in future clinical scenarios.
Background
Laparoscopic common bile duct exploration (LCBDE) is an underutilized therapy for choledocholithiasis. The driving factors of this practice gap are poorly defined. We sought to evaluate ...the attitudes and practice patterns of surgeons who underwent training courses using an LCBDE simulator.
Methods
Surgeons completed a half-day simulator-based LCBDE curriculum at national courses, including the American College of Surgeons Advanced Skills Training for Rural Surgeons and the Society of American Gastrointestinal and Endoscopic Surgeons annual meeting. Attitudes were assessed with Likert surveys immediately before and after curriculum completion. Follow-up surveys were distributed electronically.
Results
159 surgeons completed training during six courses. Surgeon attitudes regarding the overall superiority of LCBDE vs. ERCP shifted towards favoring LCBDE after course participation (4.0 vs 3.3; Likert scale 1–5,
p
< 0.001). 44% of surgeons completed follow-up surveys at a mean of 3 years post-course. Surgeons remained confident in their ability to perform LCBDE, with only 14% rating their skill as a significant barrier to practice, as compared with 43% prior to course participation (
p
< 0.01). However, only 28% of surgeons saw an increase in LCBDE volume. Deficiencies in operating room (OR) staff knowledge and instrument availability were the most significant barriers to post-course practice implementation and were inversely correlated with LCBDE case volume (
ρ
= − 0.44 and − 0.47, both
p
< 0.01). Surgeons for whom OR staff knowledge of LCBDE was not a significant barrier performed nearly 4 times more LCBDE than those who rated staff knowledge as a moderate, strong, or complete barrier.
Conclusions
Surgeons trained at an LCBDE course retained long-term confidence in their procedural ability. Practice implementation was hindered by deficiencies in OR staff knowledge and instrument availability. Surgeons with knowledgeable operating room staff performed significantly more LCBDEs than those with less capable assistance. These barriers should be addressed in future curricula to improve procedural adoption.
Aerosols in the atmosphere are chemically complex with thousands of chemical
species distributed in different proportions across individual particles in
an aerosol population. An internal mixing ...assumption, with species present in
the same proportions across all aerosols, is used in many models and
calculations of secondary organic aerosol (SOA) formation, cloud activation,
and aerosol optical properties. However, many of these effects depend on the
distribution of species within individual particles, and important
information can be lost when internal mixtures are assumed. Herein, we show
that – as found during the Southern Oxidant and Aerosol Study (SOAS) in
Centreville, Alabama, at a rural, forested location – aerosols frequently
are not purely internally mixed, even in the accumulation mode
(0.2–1.0 µm). A range of aerosol sources and the mixing state were
determined using computer-controlled scanning electron microscopy with
energy-dispersive X-ray spectroscopy (CCSEM-EDX) and scanning transmission
X-ray microscopy–near-edge X-ray absorption fine structure spectroscopy
(STXM-NEXAFS). Particles that were dominated by SOA and inorganic salts
(e.g., ammonium sulfate) were the majority of particles by number fraction
from 0.2 to 5 µm with an average of 78 % SOA in the
accumulation mode. However, during certain periods contributions by sea spray
aerosol (SSA) and mineral dust were significant to accumulation (22 % SSA
and 26 % dust) and coarse-mode number concentrations (38 % SSA and
63 % dust). The fraction of particles containing key elements (Na, Mg, K,
Ca, and Fe) were determined as a function of size for specific classes of
particles. Within internally mixed SOA/sulfate particles < 5 %
contained Na, Mg, K, Ca, or Fe, though these nonvolatile cations were present
in particles from the other sources (e.g., SSA and dust). Mass estimates of
the aerosol elemental components were used to determine the extent of
internal versus external mixing by calculating the mixing state index (χ). The aerosol population was more externally mixed than internally mixed
during all time periods analyzed. Accumulation mode aerosol ranged from more
internally mixed during SOA periods to mostly externally mixed during dust
periods. Supermicron aerosols were most externally mixed during SOA time
periods, when more SOA particles added a distinct supermicron class, and more
internally mixed when dominated by a single particle type (e.g., SSA or
dust). These results emphasize that neither external nor internal mixtures
fully represent the mixing state of atmospheric aerosols, even in a rural,
forested environment, which has important implications for air quality and
climate modeling.
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