Pirfenidone: Molecular Mechanisms and Potential Clinical Applications in Lung Disease.

Pirfenidone (PFD) is a pharmacological compound with therapeutic efficacy in idiopathic pulmonary fibrosis. It has been chiefly characterized as an antifibrotic agent, although it was initially developed as an antiinflammatory compound because of its ability to diminish the accumulation of inflammatory cells and cytokines. Despite recent studies that have elucidated key mechanisms, the precise molecular activities of PFD remain incompletely understood. PFD modulates fibrogenic growth factors, thereby attenuating fibroblast proliferation, myofibroblast differentiation, collagen and fibronectin synthesis, and deposition of extracellular matrix. This effect is mediated by suppression of TGF-ß1 (transforming growth factor-ß1) and other growth factors. Here, we appraise the impact of PFD on TGF-ß1 production and its downstream pathways. Accumulating evidence indicates that PFD also downregulates inflammatory pathways and therefore has considerable potential as a viable and innovative antiinflammatory compound. We examine the effects of PFD on inflammatory cells and the production of pro- and antiinflammatory cytokines in the lung. In this context, recent evidence that PFD can target inflammasome pathways and ensuing lung inflammation is highlighted. Finally, the antioxidant properties of PFD, such as its ability to inhibit redox reactions and regulate oxidative stress-related genes and enzymes, are detailed. In summary, this narrative review examines molecular mechanisms underpinning PFD and its recognized benefits in lung fibrosis. We highlight preclinical data that demonstrate the potential of PFD as a nonsteroidal antiinflammatory agent and outline areas for future research.

Activation of cGAS-dependent antiviral responses by DNA intercalating agents.

Acridine dyes, including proflavine and acriflavine, were commonly used as antiseptics before the advent of penicillins in the mid-1940s. While their mode of action on pathogens was originally attributed to their DNA intercalating activity, work in the early 1970s suggested involvement of the host immune responses, characterized by induction of interferon (IFN)-like activities through an unknown mechanism. We demonstrate here that sub-toxic concentrations of a mixture of acriflavine and proflavine instigate a cyclic-GMP-AMP (cGAMP) synthase (cGAS)-dependent type-I IFN antiviral response. This pertains to the capacity of these compounds to induce low level DNA damage and cytoplasmic DNA leakage, resulting in cGAS-dependent cGAMP-like activity. Critically, acriflavine:proflavine pre-treatment of human primary bronchial epithelial cells significantly reduced rhinovirus infection. Collectively, our findings constitute the first evidence that non-toxic DNA binding agents have the capacity to act as indirect agonists of cGAS, to exert potent antiviral effects in mammalian cells.

Human Metapneumovirus Infection in Chronic Obstructive Pulmonary Disease: Impact of Glucocorticosteroids and Interferon.

Background: Human metapneumovirus (hMPV) infection is implicated in exacerbations of asthma and chronic obstructive pulmonary disease (COPD). Research into the pathogenesis of infection is restricted to animal models, and information about hMPV replication and inflammatory and immune responses in human disease is limited. Methods: Human primary bronchial epithelial cells (PBECs) from healthy and asthmatic subjects and those with COPD were infected with hMPV, with or without glucocorticosteroid (GCS) exposure. Viral replication, inflammatory and immune responses, and apoptosis were analyzed. We also determined whether adjuvant interferon (IFN) can blunt hMPV infection in vitro and in a murine model. Results: hMPV infected human PBECs and viral replication was enhanced in cells from patients with COPD. The virus induced gene expression of IFN-stimulated gene 56 (ISG56) and IFN-ß, as well as IFN-γ-inducible protein 10 (IP-10) and regulated on activation, normal T cell expressed and secreted (RANTES), and more so in cells from patients with COPD. GCS exposure enhanced hMPV replication despite increased IFN expression. Augmented virus replication associated with GCS was mediated by reduced apoptosis via induction of antiapoptotic genes. Adjuvant IFN treatment suppressed hMPV replication in PBECs and reduced hMPV viral titers and inflammation in vivo. Conclusions: hMPV infects human PBECs, eliciting innate and inflammatory responses. Replication is enhanced by GCS and adjuvant IFN is an effective treatment, restricting virus replication and proinflammatory consequences of hMPV infections.

Role of human metapneumovirus and respiratory syncytial virus in asthma exacerbations: where are we now?

Since its discovery in 2001, human metapneumovirus (hMPV) has been identified as an important cause of respiratory tract infection in young children, second only to the closely related respiratory syncytial virus (RSV). Clinical evidence suggests that hMPV is associated with acute exacerbations of asthma in both children and adults, and may play a role in initiating asthma development in children. Animal models have demonstrated that airway hyperresponsiveness (AHR) and inflammation are triggered following hMPV infection, and hMPV is able to persist in vivo by inhibiting innate immune responses and causing aberrant adaptive responses. In this review, we discuss the prevalence of hMPV infection in pediatric and adult populations and its potential role in asthma exacerbation. We also review recent advances made in animal models to determine immune responses following hMPV infection, and compare to what is known about RSV.

In the Shadow of Fibrosis: Innate Immune Suppression Mediated by Transforming Growth Factor-ß.

Transforming growth factor-ß (TGFB) regulates cell proliferation, differentiation, apoptosis, and matrix homeostasis and is intimately involved in fibrosis. TGFB expression is increased in fibrotic lung diseases, such as idiopathic pulmonary fibrosis, and in chronic inflammatory conditions, such as chronic obstructive pulmonary disease and asthma. In addition to exhibiting profibrotic activities, the protein exhibits profound immune-suppressive actions involving both innate and adaptive responses, but often this aspect of TGFB biology is overlooked. Recent investigations have demonstrated that TGFB causes wide-ranging immune suppression, including blunting of pivotal early innate IFN responses. These activities permit severe virus infections, often followed by secondary bacterial infections, which may last longer, with augmented inflammation, scarring, fibrosis, and loss of lung function. Strategies to oppose TGFB actions or to enhance IFN responses may help ameliorate the detrimental consequences of infection in patients with diseases characterized by TGFB overexpression, inflammation, and fibrosis.

Hyperglycemia down-regulates cGMP-dependent protein kinase I expression in first trimester cytotrophoblast cells.

Diabetes in pregnancy is associated with microvascular complications and a higher incidence of preeclampsia. The regulatory signaling pathways involving nitric oxide, cGMP, and cGMP-dependent protein kinase (PKG) have been shown to be down-regulated under diabetic conditions and contribute to the pathogenesis of vascular complications in diabetes. The present study was undertaken to investigate how high glucose concentrations regulate PKG expression in cytotrophoblast cells (CTBs). Human CTBs (Sw. 71) were treated with 45, 135, 225, 495, or 945 mg/dL glucose for 48 h. Some cells were pretreated with a p38 inhibitor (10 µM SB203580) or 10 µM rosiglitazone. After treatment, the cell lysates were subjected to measure the expression of protein kinase G1α (PKG1α), protein kinase G1ß (PKG1ß), soluble guanylate cyclase 1α (sGC1α), and soluble guanylate cyclase 1 ß (sGC1ß) by Western blot. Statistical comparisons were performed using analysis of variance with Duncan's post hoc test. The expressions of PKG1α, PKG1ß, sGC1α, and sGC1ß were significantly down-regulated (p < 0.05) in CTBs treated with >135 mg/dL glucose compared to basal (45 mg/dL). The hyperglycemia-induced down-regulation of cGMP and cGMP-dependent PKG were attenuated by the SB203580 or rosiglitazone pretreatment. Exposure of CTBs to excess glucose down-regulates cGMP and cGMP-dependent PKG, contributing to the development of vascular complications in diabetic mothers during pregnancy. The attenuation of hyperglycemia-induced down-regulation of PKG proteins by SB203580 or rosiglitazone pretreatment further suggests the involvement of stress signaling mechanisms in this process.

The flavonoid quercetin decreases ACE2 and TMPRSS2 expression but not SARS-CoV-2 infection in cultured human lung cells.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds to angiotensin-converting enzyme 2 (ACE2) on host cells, via its spike protein, and transmembrane protease, serine 2 (TMPRSS2) cleaves the spike-ACE2 complex to facilitate virus entry. As rate-limiting steps for virus entry, modulation of ACE2 and/or TMPRSS2 may decrease SARS-CoV-2 infectivity and COVID-19 severity. In silico modeling suggested the natural bioactive flavonoid quercetin can bind to ACE2 and a recent randomized clinical trial demonstrated that oral supplementation with quercetin increased COVID-19 recovery. A range of cultured human cells were assessed for co-expression of ACE2 and TMPRSS2. Immortalized Calu-3 lung cells, cultured and matured at an air-liquid interface (Calu-3-ALIs), were established as the most appropriate. Primary bronchial epithelial cells (PBECs) were obtained from healthy adult males (N = 6) and cultured under submerged conditions to corroborate the outcomes. Upon maturation or reaching 80% confluence, respectively, the Calu-3-ALIs and PBECs were treated with quercetin, and mRNA and protein expression were assessed by droplet digital PCR and ELISA, respectively. SARS-CoV-2 infectivity, and the effects of pre- and co-treatment with quercetin, was assessed by median tissue culture infectious dose assay. Quercetin dose-dependently decreased ACE2 and TMPRSS2 mRNA and protein in both Calu-3-ALIs and PBECs after 4 h, while TMPRSS2 remained suppressed in response to prolonged treatment with lower doses (twice daily for 3 days). Quercetin also acutely decreased ADAM17 mRNA, but not ACE, in Calu-3-ALIs, and this warrants further investigation. Calu-3-ALIs, but not PBECs, were successfully infected with SARS-CoV-2; however, quercetin had no antiviral effect, neither directly nor indirectly through downregulation of ACE2 and TMPRSS2. Calu-3-ALIs were reaffirmed to be an optimal cell model for research into the regulation of ACE2 and TMPRSS2, without the need for prior genetic modification, and will prove valuable in future coronavirus and respiratory infectious disease work. However, our data demonstrate that a significant decrease in the expression of ACE2 and TMPRSS2 by a promising prophylactic candidate may not translate to infection prevention.

Effectiveness of Manual Hysteroscopic Tissue Removal Device for Intrauterine Polyps in Infertile Women in Both Operating and Office Settings.

Background: Mechanical hysteroscopic tissue removal (mHTR) systems are widely used for removing intrauterine pathology. Given the startup and procedural costs for electrically powered mechanical units, disposable manual mHTR systems have been developed. Methods: With little published, we describe its effectiveness for hysteroscopic intrauterine polypectomy. Results: One-hundred fifty-seven infertile women underwent hysteroscopic polypectomy with the manual mHTR device. Complete removal was accomplished in all but three cases, with blood loss being <10 mL and all specimens deemed sufficient for histopathologic diagnosis. Conclusions: These results suggest that the disposable manual mHTR system is effective in removing endometrial polyps. Head-to-head comparisons with other alternative technologies are needed.

Mitochondrially localised MUL1 is a novel modulator of antiviral signaling.

The innate immune response to virus must be balanced to eliminate infection yet limit damaging inflammation. A critical arm of the antiviral response is launched by the retinoic acid-inducible-gene I (RIG-I) protein. RIG-I is activated by viral RNA then associates with the mitochondrial antiviral signaling (MAVS) protein to subsequently induce potent inflammatory cytokines. Here, we demonstrate the mitochondrial E3 ubiquitin protein ligase 1 (MUL1) is a crucial moderator of RIG-I signaling. MUL1 is localized to the mitochondria where it interacts with MAVS and catalyzes RIG-I post-translational modifications that inhibit RIG-I-dependent cell signaling. Accordingly, depletion of MUL1 potentiated RIG-I mediated nuclear factor-kappa B (NF-κB) and interferon (IFN) ß reporter activity. Moreover, depletion of MUL1 boosted the antiviral response and increased proinflammatory cytokines following challenge with the RNA mimetic poly I:C and Sendai virus. We therefore submit that MUL1 is a novel regulator of the RIG-I-like receptor-dependent antiviral response, that otherwise functions to limit inflammation.

Pharmacological inhibition of TBK1/IKKε blunts immunopathology in a murine model of SARS-CoV-2 infection.

TANK-binding kinase 1 (TBK1) is a key signalling component in the production of type-I interferons, which have essential antiviral activities, including against SARS-CoV-2. TBK1, and its homologue IκB kinase-ε (IKKε), can also induce pro-inflammatory responses that contribute to pathogen clearance. While initially protective, sustained engagement of type-I interferons is associated with damaging hyper-inflammation found in severe COVID-19 patients. The contribution of TBK1/IKKε signalling to these responses is unknown. Here we find that the small molecule idronoxil inhibits TBK1/IKKε signalling through destabilisation of TBK1/IKKε protein complexes. Treatment with idronoxil, or the small molecule inhibitor MRT67307, suppresses TBK1/IKKε signalling and attenuates cellular and molecular lung inflammation in SARS-CoV-2-challenged mice. Our findings additionally demonstrate that engagement of STING is not the major driver of these inflammatory responses and establish a critical role for TBK1/IKKε signalling in SARS-CoV-2 hyper-inflammation.

Reviewer Feedback for Abstract Submissions to the Pediatric Academic Societies Meeting: A Pilot Project.

PURPOSE: To describe and evaluate a pilot project to provide reviewer comments to authors who submitted abstracts to the Hospital-based medicine topic area for the Pediatric Academic Societies (PAS) 2021 annual meeting METHODS: Abstract reviewers were encouraged via email to include reviewer comments for authors in their abstract reviews. Unedited comments were emailed to authors shortly after the abstract decision notifications were sent. We quantified the number of reviewers who commented per abstract. Additionally, we surveyed authors and reviewers to evaluate the perceived impact of the pilot project. RESULTS: For 123 abstracts submitted to the Hospital-based medicine topic area, every abstract received comments from at least one reviewer, and a median (IQR) of 4 (3-5) reviewers commented per abstract. The response rates for the author and reviewer surveys were 61/114 (54%) and 54/84 (64%), respectively, and both groups of respondents generally favored the pilot program. The majority of authors (59%) made changes to their project based on the feedback provided and 96% reported that they would like to continue to receive reviewer feedback for future PAS abstract submissions. Reviewers reported spending a mean of 11 minutes reviewing each abstract. Most (85%) felt that they spent the same or slightly more (1%-25%) time reviewing than in prior years. Multiple open-ended comments were provided, largely positive. CONCLUSION: A pilot program to incorporate reviewer feedback into abstract decision notification for a large national research meeting was successful. This approach should be considered for future meetings to enhance this integral component of academic development.

Predictors of intraoperative pain during cesarean delivery under regional anesthesia.

It is unclear why some patients experience pain during cesarean delivery despite receiving appropriate regional anesthesia. Our primary aim was to determine what demographic and clinical variables predict intraoperative pain during cesarean delivery with neuraxial anesthesia. From July 2019 through March 2020, we administered a previously validated patient satisfaction survey to parturients who had a cesarean delivery under regional anesthesia for nonemergent obstetric indications. We performed a post hoc analysis restricted to subjects who had single injection spinal and combined spinal-epidural anesthesia. Parturients who did and did not report pain differed in height, intrathecal hyperbaric bupivacaine dose, and the time from incision to wound closure. We performed an ordinal logistic regression analysis on the 168 subjects with complete data using the aforementioned variables along with the time of day of cesarean delivery. Incision to wound closure time (P < 0.01) predicted intraoperative pain. The multivariate logistic regression model was statistically significant (P < 0.01) and had a receiver operator curve value of 0.74. The duration of time from incision to wound closure predicted intraoperative pain during cesarean delivery under regional anesthesia.

Genistein Targets STING-Driven Antiviral Responses.

Cytoplasmic detection of DNA by cyclic GMP-AMP (cGAMP) synthase (cGAS) is an essential component of antiviral responses. Upon synthesis, cGAMP binds to the stimulator of interferon (IFN) genes (STING) in infected and adjacent cells through intercellular transfer by connexins forming gap-junctions, eliciting a strong IFN-ß-driven antiviral response. We demonstrate here that Genistein, a flavonoid compound naturally occurring in soy-based foods, inhibits cGAS-STING antiviral signaling at two levels. First, Genistein pretreatment of cGAMP-producing cells inhibited gap-junction intercellular communication, resulting in reduced STING responses in adjacent cells. In addition, Genistein directly blocked STING activation by the murine agonist DMXAA, by decreasing the interaction of STING with TBK1 and IKKε. As a result, Genistein attenuated STING signaling in human and mouse cells, dampening antiviral activity against Semliki Forest Virus infection. Collectively, our findings identify a previously unrecognized proviral activity of Genistein mediated via its inhibitory effects at two levels of cGAS-STING signaling. IMPORTANCE Several reports suggest that Genistein exhibits antiviral activities against DNA viruses. Our work uncovers a previously unrecognized proviral effect of Genistein, through inhibition of the cGAS-STING pathway at the level of cGAMP transfer and its sensing by STING. This suggests that the use of Genistein as an antiviral should be taken with caution as it may reduce the protective antiviral effects elicited by host STING activation.

Transforming growth factor-beta enhances rhinovirus infection by diminishing early innate responses.

Individuals with asthma are prone to viral and bacterial infections, and most asthma exacerbations have been linked to viruses, particularly rhinovirus. Excess transforming growth factor (TGF)-beta present in asthmatic airways may cause immune suppression, as well as transdifferentiate fibroblasts to myofibroblasts, thereby augmenting proinflammatory responses after rhinovirus infection. After rhinovirus infection we examined virus replication and host cell immune responses in airway fibroblasts in the presence of TGF-beta1 and in myofibroblasts. Primary culture fibroblasts were pretreated with TGF-beta1 or transdifferentiated into myofibroblasts, and then infected with rhinovirus. Viral replication, virus release, chemokine production, and interferon (IFN) responses were measured over 72 hours. Rhinovirus replication and virus release into supernatants were enhanced in fibroblasts incubated with TGF-beta1 and in fibroblasts obtained from patients with asthma. Myofibroblasts also showed more rhinovirus replication, and infected myofibroblasts produced excess neutrophil chemokines. Examination of innate responses revealed blunting of type I IFN reactions with dissociated viral RNA and IFN mRNA responses. Addition of type I IFN restituted antiviral responses, and the effect of TGF-beta1 appeared to be mediated via actions on IFN regulatory factor-3 pathways. These data demonstrate that TGF-beta1 mediates enhanced virus replication and proinflammatory responses in airway cells. TGF-beta may act as an endogenous immunosuppressant promoting virus replication and inflammation during the evolution of acute severe asthma associated with rhinovirus infection.

Attitudes of Trainees in Obstetrics and Gynecology Regarding the Structure of Residency Training.

OBJECTIVE: To measure future and current resident perspectives on obstetrics and gynecology residency training structure and possible future models. METHODS: Medical students invited for obstetrics and gynecology residency interviews and residents (postgraduate year [PGY]-1-4) at the University of Colorado, the University of Washington, the University of California San Francisco, Loyola University, Saint Joseph's Hospital, and Texas A&M in 2017-2018 received a voluntary, electronic survey regarding possible models for restructuring residency training. Student and resident responses were compared using χ test for categorical and two-sample t-test for continuous items. RESULTS: Applicants (63%, 280/444) and residents (66%, 101/153) had similar response rates (overall response rate 64%). Applicants (24%) and residents (29%) reported having concerns about the current structure of residency training. The ideal residency duration was reported as 4 years by 72% of applicants and 85% of residents. Lack of gynecologic surgical volume was the most frequently reported concern among applicants (75%) and residents (72%). Fourth-year tracking (focusing on training aligned with postgraduation career path) was preferred by 90% of applicants and 77% of residents (P=.002) and 92% among respondents planning fellowship. Most applicants (68%) and residents (75%) preferred not starting fellowship training after the 3rd year of residency. DISCUSSION: The majority of learners surveyed support a 4-year training structure but likewise support individualizing training in PGY-4. It is imperative that obstetrics and gynecology leadership consider this and other feedback from learners when considering modifications to the current training paradigm.

Career Expectations of Obstetrics and Gynecology Residents and Future Residents.

OBJECTIVE: To understand contemporary fourth-year medical student and resident career expectations in obstetrics and gynecology. METHODS: Students invited for obstetrics and gynecology residency interviews and residents (postgraduate years 1-4) at the University of Colorado, University of Washington, University of California San Francisco, Loyola University, St. Joseph's Hospital, and Texas A&M in 2016-2017 received a voluntary, electronic survey regarding career expectations. Questions were compared between students and residents using a χ test for category responses and for age a two-sample t test. RESULTS: Response rates were similar between students (68% [277/409]) and residents (63% [97/153]). Residents compared with students were more frequently planning to enter private practice (43% vs 19%) and less frequently planning an academic career (19.4% vs 30.4%) or subspecialties (38% vs 51%) (P<.001). Although most respondents planned to work full-time (96% vs 94.9%), 83% (vs 94%) of residents planned to work greater than 40 hours per week (P<.001). Respondents reported greater than $150,000 in educational debt (65%) and anticipated starting salary greater than $200,000 (89%). More residents planned to retire by age 60 years (23% vs 7%) (P<.001). Thirty-eight percent of residents reported having changed career plans during residency, citing work-life balance as the most important factor (89%). DISCUSSION: Trainees' career expectations appear to evolve over time moving toward a higher likelihood to pursue private practice, work fewer hours, and retire earlier despite large educational debt. It is critical that the specialty understand these trends when planning to address national workforce needs.