The emerging role of pyroptosis-related inflammasome pathway in atherosclerosis.

Atherosclerosis (AS), a chronic sterile inflammatory disorder, is one of the leading causes of mortality worldwide. The dysfunction and unnatural death of plaque cells, including vascular endothelial cells (VEC), macrophages, and vascular smooth muscle cells (VSMC), are crucial factors in the progression of AS. Pyroptosis was described as a form of cell death at least two decades ago. It is featured by plasma membrane swelling and rupture, cell lysis, and consequent robust release of cytosolic contents and pro-inflammatory mediators, including interleukin-1ß (IL-1ß), IL-18, and high mobility group box 1 (HMGB1). Pyroptosis of plaque cells is commonly observed in the initiation and development of AS, and the levels of pyroptosis-related proteins are positively correlated with plaque instability, indicating the crucial contribution of pyroptosis to atherogenesis. Furthermore, studies have also identified some candidate anti-atherogenic agents targeting plaque cell pyroptosis. Herein, we summarize the research progress in understating (1) the discovery and definition of pyroptosis; (2) the characterization and molecular mechanisms of pyroptosis; (3) the regulatory mechanisms of pyroptosis in VEC, macrophage, and VSMC, as well as their potential role in AS progression, aimed at providing therapeutic targets for the prevention and treatment of AS.

Lymph node ratio-based the ypTNrM staging system for gastric cancer after neoadjuvant therapy: a large population-based study.

PURPOSES: The lymph node ratio (LNR) has been considered a better prognostic factor than traditional N staging in patients with gastric cancer (GC), but its accuracy is unclear for those who receive neoadjuvant therapy (NAT). We aimed to compare the node ratio (Nr) staging with the ypN staging and to thereby develop a modified staging system incorporating Nr staging. METHODS: A total of 1791 patients who underwent gastrectomy after NAT in the Surveillance, Epidemiology, and End Results database were retrospectively analyzed. ypTNrM staging was established based on the overall survival (OS). RESULTS: The Nr staging was generated using 0.2 and 0.5 as the cutoff values of LNR and represented patients with more homogeneous OS compared with ypN staging. The 5-year OS rates for ypTNrM stages IA, IB, II, IIIA, and IIIB were 70.2%, 54.2%, 36.0%, 21.2%, and 6.6%, respectively, compared with 58.8%, 39.1%, and 21.6% for ypTNM stages I, II, and III, respectively. Compared with the ypTNM staging system, the ypTNrM staging system had a lower misclassification rate (3.0% vs. 50.9%) and better prognostic predictive power (C-index: 0.645 vs. 0.589, P < 0.001). CONCLUSIONS: The ypTNrM staging system incorporating Nr staging may provide a more accurate assessment in the clinical decision-making process for GC after NAT.

Early and late recurrences in lymph node-negative gastric cancer: a retrospective cohort study.

BACKGROUND: Predictors of recurrence in patients with lymph node-negative gastric cancer (GC) who have undergone curative resection have been widely investigated, but not the effects of predictors on timing of recurrence. OBJECTIVE: Determine the factors associated with early and late recurrence in patients with node-negative GC. DESIGN: Retrospective cohort. SETTING: Academic tertiary care center. PATIENTS AND METHODS: The study included patients with node-negative GC after curative resection between 2008 and 2018 at two institutions. Early and late recurrences were determined using a minimum P value approach to evaluate the optimal cutoff for recurrence-free survival (RFS). A competing risk model and landmark analysis were used to analyze factors associated with early and late recurrences. MAIN OUTCOME MEASURES: Recurrence-free survival and factors associated with survival. SAMPLE SIZE: 606. RESULTS: After a median follow-up of 70 months, 50 (8.3%) patients experienced recurrent disease. The optimal length of RFS for distinguishing between early (n=26) and late recurrence (n=24) was 24 months (P=.0013). The median RFS in the early and late recurrence groups was 11 and 32 months, respectively. Diffuse tumors (hazard ratio 3.358, P=.014), advanced T stage (HR 8.804, P=.003), perineural invasion (HR 10.955, P<.001), and anemia (HR 2.351, P=.018) were independent predictors of early recurrence. Mixed tumor location (HR 5.586, P=.002), advanced T stage (HR 5.066, P<.001), lymphovascular invasion (HR 5.902, P<.001), and elevated CA19-9 levels (HR 5.227, P<.001) were independent predictors of late recurrence. Similar results were obtained in the landmark analysis. CONCLUSIONS: Individualized therapeutic and follow-up strategies should be considered in future studies because of distinct patterns in predictors of early and late recurrence. LIMITATIONS: Retrospective design, small sample size. CONFLICT OF INTEREST: None.

Improving antitumor immunity using antiangiogenic agents: Mechanistic insights, current progress, and clinical challenges.

Cancer immunotherapy, especially immune checkpoint blockade (ICB), has revolutionized oncology. However, only a limited number of patients benefit from immunotherapy, and some cancers that initially respond to immunotherapy can ultimately relapse and progress. Thus, some studies have investigated combining immunotherapy with other therapies to overcome resistance to monotherapy. Recently, multiple preclinical and clinical studies have shown that tumor vasculature is a determinant of whether immunotherapy will elicit an antitumor response; thus, vascular targeting may be a promising strategy to improve cancer immunotherapy outcomes. A successful antitumor immune response requires an intact "Cancer-Immunity Cycle," including T cell priming and activation, immune cell recruitment, and recognition and killing of cancer cells. Angiogenic inducers, especially vascular endothelial growth factor (VEGF), can interfere with activation, infiltration, and function of T cells, thus breaking the "Cancer-Immunity Cycle." Together with immunostimulation-regulated tumor vessel remodeling, VEGF-mediated immunosuppression provides a solid therapeutic rationale for combining immunotherapy with antiangiogenic agents to treat solid tumors. Following the successes of recent landmark phase III clinical trials, therapies combining immune checkpoint inhibitors (ICIs) with antiangiogenic agents have become first-line treatments for multiple solid tumors, whereas the efficacy of such combinations in other solid tumors remains to be validated in ongoing studies. In this review, we discussed synergies between antiangiogenic agents and cancer immunotherapy based on results from preclinical and translational studies. Then, we discussed recent progress in randomized clinical trials. ICI-containing combinations were the focus of this review because of their recent successes, but combinations containing other immunotherapies were also discussed. Finally, we attempted to define critical challenges in combining ICIs with antiangiogenic agents to promote coordination and stimulate collaboration within the research community.

Role of Extracellular Polymeric Substances in a Methane Based Membrane Biofilm Reactor Reducing Vanadate.

For the first time, we demonstrated vanadate (V(V)) reduction in a membrane biofilm reactor (MBfR) using CH4 as the sole electron donor. The V(V)-reducing capability of the biofilm kept increasing, with complete removal of V(V) achieved when the influent surface loading of V(V) was 363 mg m-2 day-1. Almost all V(V) was reduced to V(IV) precipitates, which is confirmed by a scanning electron microscope coupled to energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). Microbial community analysis revealed that denitrifiers Methylomonas and Denitratisoma might be the main genera responsible for V(V) reduction. The constant enrichment of Methylophilus suggests that the intermediate (i.e., methanol) from CH4 metabolism might be used as the electron carriers for V(V) bioreduction. Intrusion of V(V) (2-5 mg/L, at the surface loading of 150-378 mg m-2 day-1) into the biofilm stimulated the secretion of extracellular polymeric substances (EPS), but high loading of V(V) (10 mg/L, at the surface loading of 668 mg m-2 day-1) decreased the amount of EPS. Metagenomic prediction analysis established the strong correlation between the secretion of EPS and the microbial metabolism associated with V(V) reduction, tricarboxylic acid cycle (TCA) cycle, methane oxidation, and ATP production, and EPS might relieve the oxidative stress induced by high loading of V(V). Colorimetric determination and a three-dimensional excitation-emission matrix (3D-EEM) showed that tryptophan and humic acid-like substances might play important roles in microbial cell protection and V(V) binding. Fourier transform infrared (FTIR) spectroscopy identified hydroxyl (-OH) and carboxyl (COO-) groups in EPS as the candidate functional groups for binding V(V).

Effects of 1,1,1-Trichloroethane and Triclocarban on Reductive Dechlorination of Trichloroethene in a TCE-Reducing Culture.

Chlorinated compounds were generally present in the environment due to widespread use in the industry. A short-term study was performed to evaluate the effects of 1,1,1- trichloroethane (TCA) and triclocarban (TCC) on trichloroethene (TCE) removal in a reactor fed with lactate as the sole electron donor. Both TCA and TCC inhibited TCE reduction, but the TCC had a more pronounced effect compared to TCA. The TCE-reducing culture, which had never been exposed to TCA before, reductively dechlorinated TCA to 1,1-dichloroethane (DCA). Below 15 µM, TCA had little effect on the transformation of TCE to cis-dichloroethene (DCE); however, the reduction of cis-DCE and vinyl chloride (VC) were more sensitive to TCA, and ethene production was completely inhibited when the concentration of TCA was above 15 µM. In cultures amended with TCC, the reduction of TCE was severely affected, even at concentrations as low as 0.3 µM; all the cultures stalled at VC, and no ethene was detected. The cultures that fully transformed TCE to ethene contained 5.2-8.1% Dehalococcoides. Geobacter and Desulfovibrio, the bacteria capable of partially reducing TCE to DCE, were detected in all cultures, but both represented a larger proportion of the community in TCC-amended cultures. All cultures were dominated by Clostridium_sensu_stricto_7, a genus that belongs to Firmicutes with proportions ranging from 40.9% (in a high TCC (15 µM) culture) to 88.2%. Methanobacteria was detected at levels of 1.1-12.7%, except in cultures added with 15 and 30 µM TCA, in which they only accounted for ∼0.4%. This study implies further environmental factors needed to be considered in the successful bioremediation of TCE in contaminated sites.

Effects of salinity on simultaneous reduction of perchlorate and nitrate in a methane-based membrane biofilm reactor.

This study builds upon prior work showing that methane (CH4) could be utilized as the sole electron donor and carbon source in a membrane biofilm reactor (MBfR) for complete perchlorate (ClO4-) and nitrate (NO3-) removal. Here, we further investigated the effects of salinity on the simultaneous removal of the two contaminants in the reactor. By testing ClO4- and NO3- at different salinities, we found that the reactor performance was very sensitive to salinity. While 0.2 % salinity did not significantly affect the hydrogen-based MBfR for ClO4- and NO3- removals, 1 % salinity completely inhibited ClO4- reduction and significantly lowered NO3- reduction in the CH4-based MBfR. In salinity-free conditions, NO3- and ClO4- removal fluxes were 0.171 g N/m2-day and 0.091 g/m2-day, respectively, but NO3- removal fluxes dropped to 0.0085 g N/m2-day and ClO4- reduction was completely inhibited when the medium changed to 1 % salinity. Scanning electron microscopy (SEM) showed that the salinity dramatically changed the microbial morphology, which led to the development of wire-like cell structures. Quantitative real-time PCR (qPCR) indicated that the total number of microorganisms and abundances of functional genes significantly declined in the presence of NaCl. The relative abundances of Methylomonas (methanogens) decreased from 31.3 to 5.9 % and Denitratisoma (denitrifiers) decreased from 10.6 to 4.4 % when 1 % salinity was introduced.

Bioreduction of Chromate in a Methane-Based Membrane Biofilm Reactor.

For the first time, we demonstrate chromate (Cr(VI)) bioreduction using methane (CH4) as the sole electron donor in a membrane biofilm reactor (MBfR). The experiments were divided into five stages lasting a total of 90 days, and each stage achieved a steady state for at least 15 days. Due to continued acclimation of the microbial community, the Cr(VI)-reducing capacity of the biofilm kept increasing. Cr(VI) removal at the end of the 90-day test reached 95% at an influent Cr(VI) concentration of 3 mg Cr/L and a surface loading of 0.37g of Cr m(-2) day(-1). Meiothermus (Deinococci), a potential Cr(VI)-reducing bacterium, was negligible in the inoculum but dominated the MBfR biofilm after Cr(VI) was added to the reactor, while Methylosinus, a type II methanotrophs, represented 11%-21% of the total bacterial DNA in the biofilm. Synergy within a microbial consortia likely was responsible for Cr(VI) reduction based on CH4 oxidation. In the synergy, methanotrophs fermented CH4 to produce metabolic intermediates that were used by the Cr(VI)-reducing bacteria as electron donors. Solid Cr(III) was the main product, accounting for more than 88% of the reduced Cr in most cases. Transmission electron microscope (TEM) and energy dispersive X-ray (EDS) analysis showed that Cr(III) accumulated inside and outside of some bacterial cells, implying that different Cr(VI)-reducing mechanisms were involved.

Quantitative detection of selenate-reducing bacteria by real-time PCR targeting the selenate reductase gene.

We designed a primer set to target selenate reductase (SerA) for detecting selenate reducing bacteria (SeRB). Our serA gene-based PCR primer set has high specificity in that it and positively amplified some SeRB, but not denitrifying bacteria (DB). Phylogenetic analysis of serA clone sequences of environmental samples from selenate-reducing membrane biofilm reactor (MBfR) biofilms showed that these sequences were closely grouped and had high similarity to selenate reductase gene sequences from SeRB Thauera selenatis and DB Dechloromonas; however, they were distant to other genes from dimethylsulfoxide (DMSO) enzyme family. Constructing a standard curve targeting the serA gene, we found that the good linearity for the qPCR assay when applied it to quantify SeRB in MBfR biofilms, and the gene copies of SeRB correlated well to the selenate removal percentages. Our results demonstrated the feasibility of using the serA gene-based PCR primer set to detect and quantify SeRB in environmental samples.

Evolution of the microbial community of the biofilm in a methane-based membrane biofilm reactor reducing multiple electron acceptors.

Previous work documented complete perchlorate reduction in a membrane biofilm reactor (MBfR) using methane as the sole electron donor and carbon source. This work explores how the biofilm's microbial community evolved as the biofilm stage-wise reduced different combinations of perchlorate, nitrate, and nitrite. The initial inoculum, carrying out anaerobic methane oxidation coupled to denitrification (ANMO-D), was dominated by uncultured Anaerolineaceae and Ferruginibacter sp. The microbial community significantly changed after it was inoculated into the CH4-based MBfR and fed with a medium containing perchlorate and nitrite. Archaea were lost within the first 40 days, and the uncultured Anaerolineaceae and Ferruginibacter sp. also had significant losses. Replacing them were anoxic methanotrophs, especially Methylocystis, which accounted for more than 25 % of total bacteria. Once the methanotrophs became important, methanol-oxidizing denitrifying bacteria, namely, Methloversatilis and Methylophilus, became important in the biofilm, probably by utilizing organic matter generated by the metabolism of methanotrophs. When methane consumption was equal to the maximum-possible electron-donor supply, Methylomonas, also an anoxic methanotroph, accounted for >10 % of total bacteria and remained a major part of the community until the end of the experiments. We propose that aerobic methane oxidation coupled to denitrification and perchlorate reduction (AMO-D and AMO-PR) directly oxidized methane and reduced NO3 (-) to NO2 (-) or N2O under anoxic condition, producing organic matter for methanol-assimilating denitrification and perchlorate reduction (MA-D and MA-PR) to reduce NO3 (-). Simultaneously, bacteria capable of anaerobic methane oxidation coupled to denitrification and perchlorate reduction (ANMO-D and ANMO-PR) used methane as the electron donor to respire NO3 (-) or ClO4 (-) directly. Graphical Abstract ᅟ.