[Mitochondrial DNA and cGAS-STING Innate Immune Signaling Pathway: Latest Research Progress].

Mitochondria are important organelles that present extensively in cells, serving diverse functions. In addition to controlling cell energy production and metabolism, mitochondria are also involved in various biological processes, including anti-infection, apoptosis, and autophagy. Harmful stimuli from external environment or those generated by the cells themselves can damage mitochondria and cause mitochondrial stress response, during which the mitochondrial matrix containing mitochondrial DNA (mtDNA) can leak into the cytoplasm. Cytoplasmic mtDNA, acting as a damage-associated molecular pattern (DAMP), can activate a panel of DNA sensors and elicit innate immune response in organisms. Cyclic GMP-AMP synthase (cGAS), a key intracellular DNA sensor, can catalyze the conversion of GTP and ATP to cyclic GMP-AMP (2'3'-cGAMP), which serves as second messenger to bind and activate stimulator of interferon gene (STING), an endoplasmic adaptor protein. Beyond its critical roles in anti-microbial immunity, cGAS-STING pathway also serves important functions in many pathological and physiological processes such as autoimmunity, tumor and senescence. In this review, we focus on how the mtDNA released during mitochonrial stress response activates the cGAS-STING innate immune signaling pathway and the associated diseases, in order to help promote basic research about the role of mitochondria in innate immunity and provide new strategies for developing mitochondria-targeting drugs.

Annexin A2 Enhances Complement Activation by Inhibiting Factor H.

Factor H is a circulating protein that regulates activation of the alternative pathway (AP) of complement. Mutations and genetic variations of factor H are associated with several AP-mediated diseases, highlighting the critical role of factor H in AP regulation. AP-mediated inflammation is typically triggered by illness or tissue injury, however, and tissue injury can trigger AP activation in individuals with fully functional factor H. This suggests that factor H function is affected by local conditions within tissues. We hypothesized that inducible proteins impair the ability of factor H to locally control the AP, thereby increasing AP activation. We used purified murine factor H to immunoprecipitate binding partners from mouse kidneys. Using immunoaffinity liquid chromatography-mass spectrometry, we identified annexin A2 as a factor H binding partner. Further experiments showed that annexin A2 reduces the binding of factor H to cell surfaces. Recombinant annexin A2 impaired complement regulation by factor H and increased complement activation on renal cell surfaces in vitro and in vivo. In a murine model of acute pneumococcal otitis media, the administration of annexin A2 increased AP-mediated bacterial opsonization and clearance. In conclusion, the local production of annexin A2 within tissues suppresses regulation of the AP by factor H. Annexin A2 can contribute to AP-mediated tissue inflammation by locally impairing factor H function, but it can also improve complement-mediated bacterial clearance.

Nematotoxic coumarins from Angelica pubescens Maxim. f. biserrata Shan et Yuan roots and their physiological effects on Bursaphelenchus xylophilus.

The ethanol extracts from the roots of Angelica pubescens Maxim. f. biserrata Shan et Yuan was toxic against the pine wood nematode Bursaphelenchus xylophilus. The ethyl acetate-soluble fraction derived from this extract increased its potency with a mortality of 95.25% in 72 hr at 1.0 mg/mL. Four nematotoxic coumarins were obtained from the ethyl acetate extract by bioassay-guided isolation. These were identified as osthole 1, columbianadin 2, bergapten 3 and xanthotoxin 4 by mass and nuclear magnetic resonance spectral data analysis. The LC50 values against B. xylophilus in 72 hr were 489.17, 406.74, 430.08, and 435.66 µM, respectively. These compounds also altered the smooth morphology of the B. xylophilus exoskeleton to a rough and pitted appearance as visualized by electron microscopy. The coumarins 1-4 possessed significant acetylcholinesterase inhibitory activities but had negligible effects on amylase and cellulase. This research provides additional clues to the nematotoxic mechanism of coumarins against the pine wood nematode B. xylophilus. This work will assist in the development of coumarin nematicides with enhanced activity using molecular modifications of the core coumarin structure.The ethanol extracts from the roots of Angelica pubescens Maxim. f. biserrata Shan et Yuan was toxic against the pine wood nematode Bursaphelenchus xylophilus. The ethyl acetate-soluble fraction derived from this extract increased its potency with a mortality of 95.25% in 72 hr at 1.0 mg/mL. Four nematotoxic coumarins were obtained from the ethyl acetate extract by bioassay-guided isolation. These were identified as osthole 1, columbianadin 2, bergapten 3 and xanthotoxin 4 by mass and nuclear magnetic resonance spectral data analysis. The LC50 values against B. xylophilus in 72 hr were 489.17, 406.74, 430.08, and 435.66 µM, respectively. These compounds also altered the smooth morphology of the B. xylophilus exoskeleton to a rough and pitted appearance as visualized by electron microscopy. The coumarins 1-4 possessed significant acetylcholinesterase inhibitory activities but had negligible effects on amylase and cellulase. This research provides additional clues to the nematotoxic mechanism of coumarins against the pine wood nematode B. xylophilus. This work will assist in the development of coumarin nematicides with enhanced activity using molecular modifications of the core coumarin structure.

Essential role of factor B of the alternative complement pathway in complement activation and opsonophagocytosis during acute pneumococcal otitis media in mice.

We recently reported that the complement system plays a pivotal role in innate immune defense against Streptococcus pneumoniae during acute otitis media (OM) in mice. The current study was designed to determine which of the complement pathways are activated during acute pneumococcal OM and whether components of complement are expressed in the middle ear epithelium. Gene expression was determined by quantitative PCR, enzyme-linked immunosorbent assay (ELISA), and immunofluorescence staining. We found that S. pneumoniae induced increased gene expression of factor B of the alternative complement pathway and C3 in mouse middle ear epithelium. Activation of factor B and C3 in the middle ear lavage fluids was significantly greater than in simultaneously obtained serum samples as determined by Western blotting. Using mice deficient in complement C1qa, factor B, and factor B/C2, we found that complement C3 activation and opsonophagocytosis of S. pneumoniae were greatly attenuated in factor B- and factor B/C2-deficient mice. These findings support the concept that local complement activation is an important host innate immune response and that activation of the alternative complement pathway represents one of the innate immune defense mechanisms against pneumococcal infection during the early stage of acute OM.

Comparison of tracheal intubation between sitting position and standing position in COVID-19 patients: A manikin study.

ABSTRACT: It is recommended to use visual laryngoscope for tracheal intubation in a Corona Virus Disease 2019 patient to keep the operator farther from the patient. How the position of the operator affects the distance in this setting is not ascertained. This manikin study compares the distances between the operator and the model and the intubation conditions when the operator is in sitting position and standing position, respectively.Thirty one anesthesiologists with minimum 3-years' work experiences participated in the study. The participant's posture was photographed when he performed tracheal intubation using UE visual laryngoscope in standing and sitting position, respectively. The shortest distance between the model's upper central incisor and operator's face screen (UF), the horizontal distance between the model's upper central incisor and the operator's face screen, the angle between the UF line and the vertical line of the model's upper central incisor were measured. The success rate of intubation, the duration of intubation procedure, the first-attempt success rate, the Cormack-Lehane grade, and operator comfort score were also recorded.When the operator performed the procedure in sitting position, the horizontal distance between the model's upper central incisor and the operator's face screen distance was significantly longer (9.5 [0.0-17.2] vs 24.3 [10.3-33.0], P ≤ .001) and the angle between the UF line and the vertical line of the model's upper central incisor angle was significantly larger (45.2 [16.3-75.5] vs 17.7 [0.0-38.9], P ≤ .001). There was no significant difference in UF distance when the operator changed the position. Cormack-Lehane grade was significantly improved when it was assessed using visual laryngoscope. Cormack-Lehane grade was not significantly different when the operator assessed it in sitting and standing position, respectively. No significant differences were found in the success rate, duration for intubation, first-attempt success rate, and operator comfort score.The operator is kept farther from the patient when he performs intubation procedure in sitting position. Meanwhile, it does not make the procedure more difficult or uncomfortable for the operator, though all the participants prefer to standing position.

Enhanced susceptibility to acute pneumococcal otitis media in mice deficient in complement C1qa, factor B, and factor B/C2.

To define the roles of specific complement activation pathways in host defense against Streptococcus pneumoniae in acute otitis media (AOM), we investigated the susceptibility to AOM in mice deficient in complement factor B and C2 (Bf/C2(-/)(-)), C1qa (C1qa(-/)(-)), and factor B (Bf(-)(/)(-)). Bacterial titers of both S. pneumoniae serotype 6A and 14 in the middle ear lavage fluid samples from Bf/C2(-/)(-), Bf(-)(/)(-), and C1qa(-/)(-) mice were significantly higher than in samples from wild-type mice 24 h after transtympanical infection (P < 0.05) and remained persistently higher in samples from Bf/C2(-/)(-) mice than in samples from wild-type mice. Bacteremia occurred in Bf/C2(-/)(-), Bf(-)(/)(-), and C1qa(-/)(-) mice infected with both strains, but not in wild-type mice. Recruitment of inflammatory cells was paralleled by enhanced production of inflammatory mediators in the middle ear lavage samples from Bf/C2(-/)(-) mice. C3b deposition on both strains was greatest for sera obtained from wild-type mice, followed by C1qa(-)(/)(-) and Bf(-)(/)(-) mice, and least for Bf/C2(-)(/)(-) mice. Opsonophagocytosis and whole-blood killing capacity of both strains were significantly decreased in the presence of sera or whole blood from complement-deficient mice compared to wild-type mice. These findings indicate that both the classical and alternative complement pathways are critical for middle ear immune defense against S. pneumoniae. The reduced capacity of complement-mediated opsonization and phagocytosis in the complement-deficient mice appears to be responsible for the impaired clearance of S. pneumoniae from the middle ear and dissemination to the bloodstream during AOM.

A meta-analysis of the comparing of the first-generation and next-generation TKIs in the treatment of NSCLC.

Background: The current standard approach to the treatment of patients with non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI)-sensitizing mutations has been the treatment with a first-generation EGFR-TKIs. While, with resistance developed against first-generation EGFR-TKIs, second/third-generation TKIs have attracted all the attention, and replaced first-generation EGFR- TKIs upon disease progression due to the greater efficacy and more favorable tolerability. In the past few years, this strategy has been challenged by clinical evidence when next-generation EGFR-TKIs are used in patients with advanced NSCLC. Objective: In this study, we performed a meta- analysis to investigate the efficacy of next-generation TKIs comparison with first-generation TKIs in the treatment of NSCLC. Methods: The multiple databases including Pubmed, Embase, Cochrane library databases were adopted to search for the relevant studies, and full-text articles involving to comparison of next-generation TKIs and first-generation TKIs were reviewed. After rigorous reviewing on quality, the data was extracted from eligible randomized controlled trial (RCT). Meta-analysis Revman 5.3 software was used to analyze the combined pooled ORs with the corresponding 95% confidence interval using fixed- or random-effects models according to the heterogeneity. Results: A total of 5 randomized controlled trials were included in this analysis. The group of next-generation TKIs did achieved benefit in progression-free survival (PFS) (OR = 0.58, 95%CI = 0.45-0.75, P＜0.0001), overall survival (OS) (OR = 0.76, 95%CI = 0.65-0.90, P = 0.001) as well with the objective response rate (ORR) (OR = 1.27, 95%CI = 1.01-1.61, P = 0.04), respectively. In the results of subgroup analysis of PFS with EGFR mutations, there is also significant differences with exon 19 deletion (OR = 0.56, 95%CI = 0.41-0.77, P = 0.0003) and exon 21 (L858R) mutation (OR = 0.60, 95%CI = 0.49-0.75, P＜＝0.00001). While, the treatment-related severe adverse event (SAE) between the next-generation TKIs and first-generation TKIs did not have statistical significance (OR = 1.48, 95%CI = 0.62-3.55, P = 0.38). Conclusion: The next-generation TKIs significantly improved efficacy outcomes in the treatment of EGFR mutation-positive advanced NSCLC compared with the first-generation TKIs, with a manageable safety profile. These results are potentially important for clinical decision making for these patients.

Regulation of transcription factors on sexual dimorphism of fig wasps.

Fig wasps exhibit extreme intraspecific morphological divergence in the wings, compound eyes, antennae, body color, and size. Corresponding to this, behaviors and lifestyles between two sexes are also different: females can emerge from fig and fly to other fig tree to oviposit and pollinate, while males live inside fig for all their lifetime. Genetic regulation may drive these extreme intraspecific morphological and behavioral divergence. Transcription factors (TFs) involved in morphological development and physiological activity may exhibit sex-specific expressions. Herein, we detect 865 TFs by using genomic and transcriptomic data of the fig wasp Ceratosolen solmsi. Analyses of transcriptomic data indicated that up-regulated TFs in females show significant enrichment in development of the wing, eye and antenna in all stages, from larva to adult. Meanwhile, TFs related to the development of a variety of organs display sex-specific patterns of expression in the adults and these may contribute significantly to their sexual dimorphism. In addition, up-regulated TFs in adult males exhibit enrichment in genitalia development and circadian rhythm, which correspond with mating and protandry. This finding is consistent with their sex-specific behaviors. In conclusion, our results strongly indicate that TFs play important roles in the sexual dimorphism of fig wasps.

Deletion of the complement C5a receptor alleviates the severity of acute pneumococcal otitis media following influenza A virus infection in mice.

There is considerable evidence that influenza A virus (IAV) promotes adherence, colonization, and superinfection by S. pneumoniae (Spn) and contributes to the pathogenesis of otitis media (OM). The complement system is a critical innate immune defense against both pathogens. To assess the role of the complement system in the host defense and the pathogenesis of acute pneumococcal OM following IAV infection, we employed a well-established transtympanically-induced mouse model of acute pneumococcal OM. We found that antecedent IAV infection enhanced the severity of acute pneumococcal OM. Mice deficient in complement C1qa (C1qa-/-) or factor B (Bf -/-) exhibited delayed viral and bacterial clearance from the middle ear and developed significant mucosal damage in the eustachian tube and middle ear. This indicates that both the classical and alternative complement pathways are critical for the oto-immune defense against acute pneumococcal OM following influenza infection. We also found that Spn increased complement activation following IAV infection. This was characterized by sustained increased levels of anaphylatoxins C3a and C5a in serum and middle ear lavage samples. In contrast, mice deficient in the complement C5a receptor (C5aR) demonstrated enhanced bacterial clearance and reduced severity of OM. Our data support the concept that C5a-C5aR interactions play a significant role in the pathogenesis of acute pneumococcal OM following IAV infection. It is possible that targeting the C5a-C5aR axis might prove useful in attenuating acute pneumococcal OM in patients with influenza infection.

Role of the alternative and classical complement activation pathway in complement mediated killing against Streptococcus pneumoniae colony opacity variants during acute pneumococcal otitis media in mice.

There is considerable evidence that phase variation among transparent and opaque colony phenotypes of Streptococcus pneumoniae (Spn) plays an important role in the pneumococcal adherence and invasion. The current study was designed to investigate the interactions of the opacity phenotype variants of Spn with specific complement pathway activation in a mouse model of acute otitis media (AOM). Although the opaque colony phenotype was expected to be more resistant to complement mediated killing compared to the transparent Spn variant, we discovered that C3b deposition on the transparent Spn is, in large part, dependent on the alternative pathway activation. There were no significant differences in resistance to complement mediated opsonophagocytosis between the two variants in factor B deficient mice. In addition, an in vitro study demonstrated that significantly more C4b-binding protein (C4BP) (the classical pathway inhibitor) and factor H (FH) (the alternative pathway inhibitor) bound to the transparent strain compared with the opaque one. Our data suggest that the difference in the relative virulence of Spn opacity phenotypes is associated with its ability to evade complement-mediated opsonophagocytosis in a mouse model of pneumococcal AOM.

Salicylic acid enhances Jaceosidin and Syringin production in cell cultures of Saussurea medusa.

Addition of 20 muM salicylic acid to Saussurea medusa cell cultures at day 6 resulted in jaceosidin and syringin productions up to 95 mg l(-1 )and 631 mg l(-1) which were, respectively, about 2.5- and 2.7-fold higher than in the control. The biomass was increased from 8 to 12 g l(-1). Expression of chalcone synthase gene (chs) increased sharply after 12 h treatment and was sustained up to 48 h; chalcone isomerase gene (chi) expression reached a peak at 24 h and decreased after 48 h; and phenylalanine ammonia-lyase activity increased by 7.5-fold (96 U mg(-1) protein) higher than in the control after 24 h. These results indicate that salicylic acid enhances the production of jaceosidin and syringin which is accompanied by induction of the related phenylpropanoid biosynthetic enzymes.