Gene mutations in sporadic lymphangioleiomyomatosis and genotype-phenotype correlation analysis.

BACKGROUND: Sporadic lymphangioleiomyomatosis (S-LAM) is a rare neoplasm with heterogeneous clinical features that is conventionally considered to be related to TSC2. This study serves to elucidate the mutation landscape and potential correlation between S-LAM genomic profiles and clinical phenotypes. METHODS: Genomic profiles of 22 S-LAM patients were obtained by sequencing genomic DNA and cell-free DNA from various specimens using an NGS (next-generation sequencing)-based tumor-driver gene panel. Detected mutations were summarized. Symptoms, serum vascular endothelial growth factor D (VEGF-D) values, pulmonary function, and six-minute walk distance (6MWD) were compared among groups with different TSC2 status and genotypes to analyze genotype-phenotype correlations. RESULTS: 67 Variants in 43 genes were detected, with a TSC2 mutation detection rate of 68.2%. The TSC2 detection rate was similar in specimens obtained either through transbronchial lung biopsy (TBLB) or surgical lung biopsy (70.0% vs. 69.2%, p > 0.05). A novel mutation in VEZF1 (c.A659G) was detected in four participants and may represent a mild disease state. TSC2 mutation was significantly related to a shorter 6MWD (p < 0.05), and a higher percentage of VEGF-D over 800 pg/mL (p < 0.05); stop-gain mutation was significantly related to a higher prevalence of pneumothorax. CONCLUSIONS: Tumor-driver mutations in genes other than TSC2 may have a role in S-LAM, and TBLB specimens are practical alternatives for genomic analysis. TSC2 mutation detectability and types are related to the disease severity and phenotypes of S-LAM.

Protein kinase A negatively regulates Ca2+ signalling in Toxoplasma gondii.

The phylum Apicomplexa comprises a group of obligate intracellular parasites that alternate between intracellular replicating stages and actively motile extracellular forms that move through tissue. Parasite cytosolic Ca2+ signalling activates motility, but how this is switched off after invasion is complete to allow for replication to begin is not understood. Here, we show that the cyclic adenosine monophosphate (cAMP)-dependent protein kinase A catalytic subunit 1 (PKAc1) of Toxoplasma is responsible for suppression of Ca2+ signalling upon host cell invasion. We demonstrate that PKAc1 is sequestered to the parasite periphery by dual acylation of PKA regulatory subunit 1 (PKAr1). Upon genetic depletion of PKAc1 we show that newly invaded parasites exit host cells shortly thereafter, in a perforin-like protein 1 (PLP-1)-dependent fashion. Furthermore, we demonstrate that loss of PKAc1 prevents rapid down-regulation of cytosolic [Ca2+] levels shortly after invasion. We also provide evidence that loss of PKAc1 sensitises parasites to cyclic GMP (cGMP)-induced Ca2+ signalling, thus demonstrating a functional link between cAMP and these other signalling modalities. Together, this work provides a new paradigm in understanding how Toxoplasma and related apicomplexan parasites regulate infectivity.

An apically located hybrid guanylate cyclase-ATPase is critical for the initiation of Ca2+ signaling and motility in Toxoplasma gondii.

Protozoan parasites of the phylum Apicomplexa actively move through tissue to initiate and perpetuate infection. The regulation of parasite motility relies on cyclic nucleotide-dependent kinases, but how these kinases are activated remains unknown. Here, using an array of biochemical and cell biology approaches, we show that the apicomplexan parasite Toxoplasma gondii expresses a large guanylate cyclase (TgGC) protein, which contains several upstream ATPase transporter-like domains. We show that TgGC has a dynamic localization, being concentrated at the apical tip in extracellular parasites, which then relocates to a more cytosolic distribution during intracellular replication. Conditional TgGC knockdown revealed that this protein is essential for acute-stage tachyzoite growth, as TgGC-deficient parasites were defective in motility, host cell attachment, invasion, and subsequent host cell egress. We show that TgGC is critical for a rapid rise in cytosolic [Ca2+] and for secretion of microneme organelles upon stimulation with a cGMP agonist, but these deficiencies can be bypassed by direct activation of signaling by a Ca2+ ionophore. Furthermore, we found that TgGC is required for transducing changes in extracellular pH and [K+] to activate cytosolic [Ca2+] flux. Together, the results of our work implicate TgGC as a putative signal transducer that activates Ca2+ signaling and motility in Toxoplasma.

Influenza Virus in Community-Acquired Pneumonia: Current Understanding and Knowledge Gaps.

Influenza virus infection poses a heavy burden on global health and economics. With the advancement in viral pathogen detection methods, the role of virus infection in community-acquired pneumonia has been increasingly recognized. The disease spectrum of influenza ranges from asymptomatic infection to severe or even fatal illness. Progress has been made in recent years to identify risk factors including lymphopenia and hypoxia for influenza mortality. Immunopathology plays an important role in influenza pathogenesis. The disturbed homeostasis after virus infection consists of both an excessive inflammatory phase and an immune suppression phase, collectively described as viral sepsis. Multiple antiviral therapies have been tested and some were advanced to late-phase clinical trials, including polymerase inhibitors, hemagglutinin inhibitors, host-acting antivirals, monoclonal antibodies, and adjunctive immunomodulatory therapies. Combination therapies have been shown to increase antiviral efficacy and genetic resistance barrier. In this review, we summarized the recent advances in our understanding of the disease pathogenesis, as well as the progress in antiviral therapy development. We also pointed out current key knowledge gaps in influenza research. Hopefully, experience gained from seasonal influenza research will prepare us for the next influenza pandemic and emerging respiratory pathogens.

Omics research in lymphangioleiomyomatosis: status and challenges.

INTRODUCTION: Lymphangioleiomyomatosis (LAM) is a rare and progressive disorder that usually arises in the lung and almost exclusively affects women of childbearing age. In recent years, a number of molecules have been shown to be differentially expressed between patients with LAM and healthy control individuals, and some of these molecules, in addition to vascular endothelial growth factor D (VEGF-D), have the potential to be novel biomarkers. AREAS COVERED: This review summarizes the recent advances in omics research, including genomics, transcriptomics, proteomics, and metabolomics, in LAM biomarker discovery. It also retrieves the literature on LAM biomarkers studied by omics techniques in the last 10 years using PubMed and other retrieval tools. EXPERT OPINION: Further research on expanded sample sizes can be conducted to construct specific models to study the role of these molecules in the pathogenesis of LAM and clarify the underlying mechanisms involved. In the future, in terms of technology, the combination of various omics methods is expected to result in novel biomarker discovery.

SIRT1 signaling pathways in sarcopenia: Novel mechanisms and potential therapeutic targets.

Sarcopenia is an aging-related skeletal disease characterized by decreased muscle mass, strength, and physical function, severely affecting the quality of life (QoL) of the elderly population. Sirtuin 1 (SIRT1), as a nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylases, has been reported to participate in various aging-related signaling pathways and exert protective effect on many human diseases. SIRT1 functioned as an important role in the occurrence and progression of sarcopenia through regulating key pathways related to protein homeostasis, apoptosis, mitochondrial dysfunction, insulin resistance and autophagy in skeletal muscle, including SIRT1/Forkhead Box O (FoxO), AMP-activated protein kinase (AMPK)/SIRT1/nuclear factor κB (NF-κB), SIRT1/p53, AMPK/SIRT1/peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), and SIRT1/live kinase B1 (LKB1)/AMPK pathways. However, the specific mechanisms of these processes have not been fully illuminated. Currently, several SIRT1-mediated interventions on sarcopenia have been preliminarily developed, such as SIRT1 activator polyphenolic compounds, exercising and calorie restriction. In this review, we summarized the predominant mechanisms of SIRT1 involved in sarcopenia and therapeutic modalities targeting the SIRT1 signaling pathways for the prevention and prognosis of sarcopenia.

Determinants of Progression and Mortality in Lymphangioleiomyomatosis.

BACKGROUND: Lymphangioleiomyomatosis is a progressive diffuse cystic lung disease with approximately 85% survival at 10 years. The determinants of disease progression and mortality after the introduction of sirolimus therapy and vascular endothelial growth factor D (VEGF-D) as a biomarker have not been well defined. RESEARCH QUESTION: Which factors, including VEGF-D and sirolimus therapy, influence disease progression and survival prognosis in patients with lymphangioleiomyomatosis? STUDY DESIGN AND METHODS: The progression dataset and the survival dataset included 282 and 574 patients, respectively, from Peking Union Medical College Hospital, Beijing, China. A mixed-effects model was used to compute the rate of decline in FEV1, and generalized linear models were used to identify variables affecting FEV1 decline. A Cox proportional hazards model was used to explore the association between clinical variables and the outcomes of death or lung transplantation in patients with lymphangioleiomyomatosis. RESULTS: VEGF-D levels and sirolimus treatment were associated with FEV1 changes and survival prognosis. Compared with patients with VEGF-D of < 800 pg/mL at baseline, patients with VEGF-D of ≥ 800 pg/mL lost FEV1 faster (SE, -38.86 mL/y; 95% CI, -73.90 to -3.82 mL/y; P = .031). The 8-year cumulative survival rates of patients with VEGF-D of ≥ 2,000 pg/mL and < 2,000 pg/mL were 82.9% and 95.1%, respectively (P = .014). The generalized linear regression model also demonstrated the benefit of delaying the decline of FEV1 by 65.56 mL/y (95% CI, 29.06-102.06 mL/y) in patients treated with sirolimus compared with those without sirolimus (P < .001). The 8-year risk of death was reduced by 85.1% (hazard ratio, 0.149; 95% CI, 0.075-0.299) after sirolimus treatment. After inverse treatment probability weighting, the risks of death in the sirolimus group were reduced by 85.6%. CT scan results of grade III severity were associated with worse progression than results of grades I or II severity. Patients with baseline FEV1 of 70% predicted or St. George's Respiratory Questionnaire Symptoms domain 50 or higher predicted a higher risk of worse survival. INTERPRETATION: Serum VEGF-D levels, a biomarker of lymphangioleiomyomatosis, are associated with disease progression and survival. Sirolimus therapy is associated with slower disease progression and better survival in patients with lymphangioleiomyomatosis. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT03193892; URL: www. CLINICALTRIALS: gov.

Sirolimus reduces the risk of pneumothorax recurrence in patients with lymphangioleiomyomatosis: a historical prospective self-controlled study.

BACKGROUND: Spontaneous pneumothorax has a high incidence and high rate of recurrence in patients with lymphangioleiomyomatosis (LAM). The risk factors for pneumothorax and the effects of sirolimus on pneumothorax in patients with LAM are unknown. In our study, multivariate logistic regression was applied to a cross-sectional cohort to investigate factors associated with pneumothorax in LAM patients. Kaplan-Meier analysis was applied in the historical prospective self-controlled study to determine whether sirolimus reduces the risk of pneumothorax recurrence in patients with LAM. RESULTS: Of the 399 patients registered with LAM-CHINA at our center between May 10, 2017 and August 31, 2020, 142 had a history of pneumothorax at registration. High CT grade and age at presentation ≤ 35 years were associated with a higher risk of pneumothorax in patients with LAM. Postmenopausal status was correlated with a lower risk of pneumothorax. In the historical prospective self-controlled study, the 5-year probability of pneumothorax recurrence was 80% lower in the sirolimus group than in the control group (hazard ratio for pneumothorax recurrence, 0.20; 95% CI, 0.14 to 0.30, P < 0.001 by log-rank test). CONCLUSION: Sirolimus reduced the risk of pneumothorax recurrence in LAM patients.

Low-to-moderate dose corticosteroids treatment in hospitalized adults with COVID-19.

OBJECTIVES: Use of corticosteroids is common in the treatment of coronavirus disease 2019, but clinical effectiveness is controversial. We aimed to investigate the association of corticosteroids therapy with clinical outcomes of hospitalized COVID-19 patients. METHODS: In this single-centre, retrospective cohort study, adult patients with confirmed coronavirus disease 2019 and dead or discharged between 29 December 2019 and 15 February 2020 were studied; 1:1 propensity score matchings were performed between patients with or without corticosteroid treatment. A multivariable COX proportional hazards model was used to estimate the association between corticosteroid treatment and in-hospital mortality by taking corticosteroids as a time-varying covariate. RESULTS: Among 646 patients, the in-hospital death rate was higher in 158 patients with corticosteroid administration (72/158, 45.6% vs. 56/488, 11.5%, p < 0.0001). After propensity score matching analysis, no significant differences were observed in in-hospital death between patients with and without corticosteroid treatment (47/124, 37.9% vs. 47/124, 37.9%, p 1.000). When patients received corticosteroids before they required nasal high-flow oxygen therapy or mechanical ventilation, the in-hospital death rate was lower than that in patients who were not administered corticosteroids (17/86, 19.8% vs. 26/86, 30.2%, log rank p 0.0102), whereas the time from admission to clinical improvement was longer (13 (IQR 10-17) days vs. 10 (IQR 8-13) days; p < 0.001). Using the Cox proportional hazards regression model accounting for time varying exposures in matched pairs, corticosteroid therapy was not associated with mortality difference (HR 0.98, 95% CI 0.93-1.03, p 0.4694). DISCUSSION: Corticosteroids use in COVID-19 patients may not be associated with in-hospital mortality.

Enhancement of the methane removal efficiency via aeration for biochar-amended landfill soil cover.

Methane (CH4) mitigation of biocovers or biofilters for landfills is influenced by the bed material and oxygen availability. The improvement of active aeration for the CH4 oxidation efficiency of biochar-amended landfill soil cover was investigated over a period of 101 days. There were column 1 as the control group, column 2 with biochar amending the soil cover, and column 3 with daily active aeration besides the same biochar amendment. All groups were inoculated with enriched methane oxidation bacteria (MOB). The average CH4 removal efficiency was up to 78.6%, 85.2% and 90.6% for column 1, 2, and 3, respectively. The depth profiles of CH4 oxidation efficiencies over the whole period also showed that the stimulation of CH4 oxidation by biochar amendment was apparent in the top 35 cm but became very faint after two months. This probably was due to the rapid depletion of nitrogen nutrition caused by enhanced methanotrophic activities. While through aeration, CH4 oxidation efficiency was further improved for column 3 than column 2. This enhancement also lasted for the whole period with a reduced decline of CH4 oxidation. Finally, the major MOB Methylocystis, commonly found in the three columns, were most abundant in the top 35 cm for column 3. A more balanced ratio of MOB and more homogeneous microbial community structures across different soil depths were also the results of active aeration.

Use of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers in context of COVID-19 outbreak: a retrospective analysis.

The possible effects of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) on COVID-19 disease severity have generated considerable debate. We performed a single-center, retrospective analysis of hospitalized adult COVID-19 patients in Wuhan, China, who had definite clinical outcome (dead or discharged) by February 15, 2020. Patients on anti-hypertensive treatment with or without ACEI/ARB were compared on their clinical characteristics and outcomes. The medical records from 702 patients were screened. Among the 101 patients with a history of hypertension and taking at least one anti-hypertensive medication, 40 patients were receiving ACEI/ARB as part of their regimen, and 61 patients were on antihypertensive medication other than ACEI/ARB. We observed no statistically significant differences in percentages of in-hospital mortality (28% vs. 34%, P = 0.46), ICU admission (20% vs. 28%, P = 0.37) or invasive mechanical ventilation (18% vs. 26%, P = 0.31) between patients with or without ACEI/ARB treatment. Further multivariable adjustment of age and gender did not provide evidence for a significant association between ACEI/ARB treatment and severe COVID-19 outcomes. Our findings confirm the lack of an association between chronic receipt of renin-angiotensin system antagonists and severe outcomes of COVID-19. Patients should continue previous anti-hypertensive therapy until further evidence is available.

Comparison of the methane-oxidizing capacity of landfill cover soil amended with biochar produced using different pyrolysis temperatures.

The in-situ mitigation of methane (CH4) in landfill gas using landfill cover soil (LCS) is a cost-effective approach, but its efficiency needs to be enhanced. In this study, we incorporated an enriched methane-oxidizing bacteria (MOB) consortium into LCS and established four biochar-amended LCS groups with biochar produced at 300 °C (BC300), 400 °C (BC400), 500 °C (BC500), and 600 °C (BC600). The purpose was to evaluate the CH4 oxidation capacity of biochar-amended LCS after inoculation with MOB and to investigate how the physicochemical properties of biochar that are influenced by the pyrolysis temperature affect the performance and microbial activity of biochar-amended LCS. It was found that a 15% volume ratio (representing a mass ratio of 2.49%-2.78%) for biochar amendment in LCS enhanced CH4 removal efficiency, with the highest removal observed to be 46% for BC400-amended LCS compared to 30% for the original LCS. In addition, CH4 adsorption by the biochar was not observed, and a 15% mass ratio for biochar in the LCS had no or a negative impact. Besides improving the water-holding capacity and gas permeability of LCS, other possible advantages of biochar amendment in terms of CH4 oxidization include greater retention of nutrients, electron acceptors, and exchangeable cations, as well as introducing iron ions. It was also found that CH4 oxidation capacity and the methanotroph activity of biochar-amended LCS did not continue to increase with higher pyrolysis temperatures, even though higher micropore volumes and surface areas were obtained at higher pyrolysis temperatures. From this study, BC400 was identified as the optimal choice for the best performance in terms of enhancing both the CH4 oxidation capacity of the amended LCS and the growth of type II methanotroph Methylocystaceae, which can possibly be attributed to having the highest cation exchange capacity of the four biochars.