Quercitrin Is a Novel Inhibitor of Salmonella enterica Serovar Typhimurium Type III Secretion System

The purpose was to screen type III secretory system (T3SS) inhibitors of Salmonella enterica serovar Typhimurium (S. Typhimurium) from natural compounds. The pharmacological activities and action mechanisms of candidate compounds in vivo and in vitro were systematically studied and analyzed. Using a SipA-β-lactamase fusion reporting system, we found that quercitrin significantly blocked the translocation of SipA into eukaryotic host cells without affecting the growth of bacteria. Adhesion and invasion assay showed that quercitrin inhibited S. Typhimurium invasion into host cells and reduced S. Typhimurium mediated host cell damage. β-galactosidase activity detection and Western blot analysis showed that quercitrin significantly inhibited the expression of SPI-1 genes (hilA and sopA) and effectors (SipA and SipC). The results of animal experiments showed that quercitrin significantly reduced colony colonization and alleviated the cecum pathological injury of the infected mice. Small molecule inhibitor quercitrin directly inhibited the function of T3SS and provided a potential antibiotic alternative against S. Typhimurium infection. Importance: T3SS plays a crucial role in the bacterial invasion and pathogenesis of S. Typhimurium. Compared with conventional antibiotics, small molecules could inhibit the virulence factors represented by S. Typhimurium T3SS. They have less pressure on bacterial vitality and a lower probability of producing drug resistance. Our results provide strong evidence for the development of novel inhibitors against S. Typhimurium infection.

Isoflavone glucoside genistin, an inhibitor targeting Sortase A and Listeriolysin O, attenuates the virulence of Listeria monocytogenes in vivo and in vitro

As a common intracellular facultative anaerobic Gram-positive bacterium, Listeria monocytogenes (L. monocytogenes) exhibits strong resistance to extreme environments, such as low temperature and a wide range of pH values, causing contamination in food production and processing. Sortase A (SrtA) and listeriolysin O (LLO), two crucial virulence factors of L. monocytogenes, are widely recognized as potential targets for the development of anti-L. monocytogenes infection drugs. In this study, we found that genistin simultaneously inhibits the peptidase activity of SrtA and the hemolytic activity of LLO without affecting the growth of L. monocytogenes, alleviating concerns about developing resistance. Furthermore, we demonstrated that genistin reduces L. monocytogenes biofilm formation and invasion of human colorectal cancer (Caco-2) cells. Subsequent mechanistic studies revealed that genistin inhibited LLO-mediated Caco-2 cell damage by blocking LLO oligomerization. Fluorescence quenching assay revealed the potential binding mode of SrtA and LLO to genistin. Genistin might bind to the active pocket of SrtA through residues Leu33, Asn29, and Met40, interacting with D1 domain of LLO involved in oligomerization and pore formation through residues Asn259. Studies in infection models revealed that genistin reduces mortality and pathological damage in mice infected with L. monocytogenes. These results indicate that genistin is a promising anti-virulence agent that could be considered an alternative candidate for the treatment of L. monocytogenes infection.

Anti-inflammatory, antioxidant and anti-virulence roles of atractylodin in attenuating Listeria monocytogenes infection

Background

Listeria monocytogenes (L. monocytogenes), as a pandemic foodborne pathogen, severely threatens food security and public health care worldwide, which evolves multiple bacterial virulence factors (such as listeriolysin O, LLO) for manipulating the immune response of L. monocytogenes-host interactions.

Methods

Hemolysis assay was employed to screen a potential LLO inhibitor and the underlying mechanisms were investigated using molecular dynamics (MD) simulation and oligomerization assay. The effects of candidates on immune response were examined by qRT-PCR and immunoblotting analysis. Histological analysis, ELISA assay and biochemistry detection were conducted to assess in vivo efficacy of candidates.

Results

In the present study, natural terpenoid atractylodin was characterized as an alternative drug candidate for the treatment of L. monocytogenes by the regulation of LLO function and host Nrf2/NLRP3 signaling pathway. Notably, in vivo infection model by L. monocytogenes also highlighted that atractylodin treatment provided effective therapeutic benefits, as evidenced by decreased bacterial burden and diminished inflammation. Congruently, the survival rate of L. monocytogenes-infection mice increased significantly from 10.0% to 40.0% by atractylodin treatment.

Conclusion

Collectively, our study showed for the first time that atractylodin has tremendous potential to attenuate L. monocytogenes pathogenicity by blocking LLO pore formation and mediating the suppression of inflammation and oxidative stress, providing a promising therapeutic strategy and broadening the applications of atractylodin against L. monocytogenes infection.

Harmine, an inhibitor of the type III secretion system of Salmonella enterica serovar Typhimurium

New therapeutic strategies for clinical Salmonella enterica serovar Typhimurium (S. Typhimurium) infection are urgently needed due to the generation of antibiotic-resistant bacteria. Inhibition of bacterial virulence has been increasingly regarded as a potential and innovative strategy for the development of anti-infection drugs. Salmonella pathogenicity island (SPI)-encoded type III secretion system (T3SS) represents a key virulence factor in S. Typhimurium, and active invasion and replication in host cells is facilitated by the secretion of T3SS effector proteins. In this study, we found that harmine could inhibit T3SS secretion; thus, its potential anti-S. Typhimurium infection activity was elucidated. Harmine inhibits the secretion and expression of T3SS effector proteins and consequently attenuates the S. Typhimurium invasion function of HeLa cells. This inhibition may be implemented by reducing the transcription of pathogenesis-related SPI-1 transcriptional activator genes hilD, hilC, and rtsA. Harmine improves the survival rate and bacterial loads of mice infected with S. Typhimurium. In summary, harmine, an effective T3SS inhibitor, could be a leading compound for the development of treatments for Salmonella infection.

Tannic Acid Inhibits Salmonella enterica Serovar Typhimurium Infection by Targeting the Type III Secretion System

Salmonella enterica serovar Typhimurium (S. Typhimurium) is a zoonotic pathogen that can cause food poisoning and diarrhea in both humans and animals worldwide. The Salmonella pathogenicity island (SPI) genes encoded type III secretion system (T3SS) is important for S. Typhimurium invasion and replication in host cells. Due to the increasing problem of antibiotic resistance, antibiotic treatment for clinical Salmonella infection has gradually been limited. Anti-virulence inhibitors are a promising alternative to antibiotics because they do not easily induce bacterial antibiotic resistance. Here, we systematically evaluated the therapeutic effect of tannic acid (TA) on Salmonella-infected mice and elucidated its anti-infection mechanism. TA treatment improved the survival rate of S. Typhimurium-infected mice and alleviated cecum pathological lesions. In addition, TA inhibited S. Typhimurium invasion to HeLa cells without affecting their growth. Further studies showed that TA could inhibit the expression of sipA and sipB. This inhibition may be implemented by inhibiting the transcription of key regulatory and structural genes of the T3SS. This study provides an alternative anti-virulence strategy for Salmonella infection treatment.

Acacetin Alleviates Listeria monocytogenes Virulence Both In Vitro and In Vivo via the Inhibition of Listeriolysin O

Listeria monocytogenes is a ubiquitous Gram-positive foodborne pathogen that is responsible for listeriosis in both humans and several animal species. The bacterium secretes a pore-forming cholesterol-dependent cytolysin, listeriolysin O (LLO), a major virulence factor involved in the activation of cellular processes. The ability of LLO to lyse erythrocytes is a measure of LLO activity. We used hemolytic activity assay to screen the LLO inhibitors. Acacetin was found to be an LLO inhibitor, which is a di-hydroxy and mono-methoxy flavone present in various plants, including Black locust, Damiana, and Silver birch. As the features of acacetin are of low toxicity and have less acquired resistance, it comes to a hotspot in drug development. In our study, we report that acacetin antagonized the hemolytic activity of L. monocytogenes culture supernatants and purified LLO by directly interfering with the formation of oligomers without inhibiting the bacterial growth and the expression of LLO. Acacetin also relieved the injury of alveolar epithelial cells by inhibiting LLO activity. Further, acacetin significantly promoted the clearance of L. monocytogenes and alleviated the histopathological damage, thereby raising survival rate, which conferred mice with effective protection against L. monocytogenes infection. Using molecular docking and dynamics simulation, we further proved the mechanism of acacetin antagonizing LLO pore-forming activity by direct binding to the second membrane-inserting helix bundle (HB2) of LLO domain 3. These data suggested that acacetin recedes the virulence of L. monocytogenes both in vivo and in vitro, and this study provided a promising candidate and potential alternative for the prevention and treatment of L. monocytogenes infections.

Phloretin potentiates polymyxin E activity against gram-negative bacteria

AIMS

The spread of plasmid-mediated polymyxin resistance has jeopardized the use of polymyxin, the last defender that combats infections caused by multidrug-resistant (MDR) gram-negative pathogens.

MAIN METHODS

In this study, phloretin, as a monomeric compound extracted from natural plants, showed a good synergistic effect with polymyxin E against gram-negative bacteria, as evaluated by minimal inhibit concentration (MIC) assay and a series of assays, including growth curve, time-killing, and Western blot assays. A model of mice infected by Salmonella sp. stain HYM2 was established to further identify the synergistic effect of phloretin with polymyxin E.

KEY FINDINGS

The results suggested that phloretin had the potential ability to recover the antibacterial sensitivity of polymyxin E from 64 μg/mL to no more than 2 μg/mL in E. coli ZJ478 or in Salmonella sp. stain HYM2 with a 32-fold decrease. A series of strains, including mcr-1-positive and mcr-1-negative strains, were treated with a combination of phloretin and polymyxin E, and the fractional inhibitory concentration (FIC) values were all found to be below 0.5. However, the combination of phloretin and polymyxin E did not lead to bacterial resistance. In vivo, the survival rate of infected mice reached nearly 80% with the combination treatment, and the cecal colony value also decreased significantly.

SIGNIFICANCE

All the above results indicated that phloretin is a potential polymyxin potentiator to combat gram-negative stains.

Inhibitory effect of hederagenin on Streptococcus pneumoniae pneumolysin in vitro

Streptococcus pneumoniae is an important pathogen that causes otitis media, pneumonia, meningitis and bacteremia. As an important virulence factors of S. pneumoniae, pneumolysin (PLY) can penetrate cell membranes and lead to cell lysis and inflammation, which is one of the main causes of infection and damage of S. pneumoniae. Therefore, using pneumolysin as a target to study its inhibitors can provide a new treatment strategy for pneumococcal disease. This study analyzed the inhibitory effect of the natural compound hederagenin on PLY in vitro. The results show that hederagenin has great potential as a new strategy for the treatment of pneumococcal diseases.

Hypoxia-mediated down-regulation of miRNAs' biogenesis promotes tumor immune escape in bladder cancer

BACKGROUND

The study examines the function of hypoxia-mediated down-regulation of microRNAs (miRNAs) (mir-30c, mir-135a, and mir-27a) in the process of bladder cancer immune escape.

METHODS

Quantitative Real-time PCR (qRT-PCR) was carried out to determine gene expression levels of Drosha and Dicer under hypoxia treatment, while western blotting and flow cytometry were used to determine protein expression. Seven reported miRNAs were identified via qRT-PCR assay. Flow cytometry detection of CD3/CD4/CD8-positive expression and statistics. Enzyme-linked immunosorbent assay (ELISA) detected cellular immune factors content. Cell apoptosis was checked via flow cytometry assay. Luciferase report assay and western blot assays were both used to verify the relationship between miRNAs and Casitas B-lineage lymphoma proto-oncogene b (Cbl-b). The animal model was established and Hematoxylin-eosin (HE) staining, TdT-mediated dUTP Nick-End Labeling (TUNEL) staining, and immunohistochemistry (IHC) assays were separately used to verify the conclusions.

RESULTS

The CD3 + /CD4 + expression was increased in the hypoxia group, while CD3 + /CD8 + expression, the cellular immune factors content Interleukin-2 (IL-2) and Tumor Necrosis Factor-α (TNFα) along with the cell apoptosis were suppressed. The protein expression of Cbl-b was found to be up-regulated in the hypoxia group. After constructing the overexpression/ knockdown of Cbl-b in peripheral blood mononuclear cell (PBMC), Cbl-b has been found to promote tumor immune escape in bladder cancer. Furthermore, Cbl-b had been identified as the co-targets of mir-30c, mir-135a, and mir-27a and down-regulation of miRNA biogenesis promotes Cbl-b expression and deactivating T cells in vitro/in vivo.

CONCLUSION

Hypoxia-mediated down-regulation of miRNAs' biogenesis promotes tumor immune escape in bladder cancer, which could bring much more advance to the medical research on tumors.

Genome-wide association study of fleece traits in Inner Mongolia Cashmere goats

Inner Mongolia Cashmere goat is a well-known local cashmere goat breed in China. It is famous for excellent fleece quality and a significant advantage in cashmere yield compared to other cashmere goat breeds. In this study, a genome-wide association study was used to investigate fiber length, fiber diameter, and cashmere yield of 192 Inner Mongolia Cashmere goats using the Illumina GoatSNP52K Beadchip panel. We discovered that four single nucleotide polymorphisms (SNPs) reached genome-wide significance levels. These SNPs were located in some genes, e.g. FGF12, SEMA3D, EVPL, and SOX5, possibly related to fleece traits in Inner Mongolia Cashmere goat. Gene ontology enrichment analysis revealed that these genes were enriched in several biological pathways that were involved in hair follicle development in cashmere goats. In summary, the identified significant SNPs and genes provide useful information to explore genetic mechanisms underlying the variation in fleece traits and genomic selection of Chinese cashmere goat.

A novel homozygous mutation (p.N958K) of SLC12A3 in Gitelman syndrome is associated with endoplasmic reticulum stress

PURPOSE

Gitelman syndrome (GS) is an autosomal recessive renal tubular disease that arises as a consequence of mutations in the SLC12A3 gene, which codes for an Na-Cl cotransporter (NCC) in distal renal tubules. This study was designed to explore the mutations associated with GS in an effort to more fully understand the molecular mechanisms governing GS.

METHODS

We analyzed SLC12A3 mutations in a pedigree including a 42-year-old male with GS as well as four related family members over three generations using Sanger and next generation sequencing approaches. We additionally explored the functional ramifications of identified mutations using both Xenopus oocytes and the HEK293T cell line.

RESULTS

We found that the subject with GS exhibited characteristic symptoms including sporadic thirst, fatigue, excess urination, and substantial hypokalemia and hypocalciuria, although magnesium levels were normal. Other analyzed subjects in this pedigree had normal laboratory findings and did not exhibit clear signs of GS. Sequencing analyses revealed that the GS subject exhibited a homozygous missense mutation (c.2874C > G, p.N958K) in exon 24 of SLC12A3. Both parents of this GS subject, as well as his older brother and daughter all exhibited heterozygous mutations at this same site. Functional analyses in Xenopus oocytes indicated that this mutated SLC12A3 gene encodes a protein which fails to mediate normal sodium transport, and when this mutant gene was expressed in HEK293T cells, we observed significant increases in endoplasmic reticulum (ER)-stress pathway activation.

CONCLUSION

The p.N958K mutation in exon 24 of SLC12A3 can trigger GS at least in part via enhancing ER stress responses.

The possible effect of different types of ventilation on reducing operation theatre infections: a meta-analysis

INTRODUCTION

The relation between type of ventilation used in the operating theatre and surgical site infection has drawn considerable attention. It has been reported that there is a possible relationship between the type of ventilation used in the operation theatre and surgical site infection. This meta-analysis was performed to evaluate this relationship.

METHODS

Through a systematic literature search up to May 2020, 14 studies describing 590,121 operations, 328,183 were performed under laminar airflow ventilation and 2,611,938 were performed under conventional ventilation. Studies were identified that reported relationships between type of ventilation with its different categories and surgical site infection (10 studies were related to surgical site infection in total hip replacement, 7 in total knee arthroplasties and 3 in different abdominal and open vascular surgery). Odds ratios with 95% confidence intervals were calculated comparing surgical site infection prevalence and type of theatre ventilation using the dichotomous method with a random or fixed-effect model.

FINDINGS

No significant difference was found between surgery performed under laminar airflow ventilation and conventional ventilation in total hip replacement (OR 1.23; 95% CI 0.97-1.56, p = 0.09), total knee arthroplasties (OR 1.14; 95% CI 0.62-2.09, p = 0.67) or different abdominal and open vascular surgery (OR 0.75; 95% CI 0.43-1.33, p = 0.33). The impact of the type of theatre ventilation may have no influence on surgical site infection as a tool for decreasing its occurrence.

CONCLUSIONS

Based on this meta-analysis, operating under laminar airflow or conventional ventilation may have no independent relationship with the risk of surgical site infection. This relationship forces us not to recommend the use of laminar airflow ventilation since it has a much higher cost compared with conventional ventilation.

Mode of action and structural modelling of the interaction of formononetin with suilysin

AIMS

Suilysin is a critical pore-forming virulence factor of Streptococcus suis that has been demonstrated to substantially contribute to its pathogenicity. We have demonstrated that formononetin alleviates S. suis infection both in vivo and in vitro by targeting suilysin. However, the molecular mechanism of the effect is unclear. Our aim was to determine the molecular mechanism of the effect of formononetin on suilysin.

METHODS AND RESULTS

The mechanism of interaction between formononetin and suilysin was investigated by molecular modelling. The results indicated that formononetin was bound at the junction of domain two and domain four of suilysin. The binding free energy values indicated that the A415, Y412, E414, N413, T61, T62 and G416 residues are critical for this binding, this observation was confirmed by the changes in the flexibility of these residues and the distances between these residues and formononetin. The inhibitory effect of formononetin on the pore-forming activity of suilysin, binding constant and binding free energy were significantly decreased by site-specific mutagenesis of Y412 and N413. Finally, we analysed the spatial configuration of suilysin before and after formononetin binding, the results indicated that the binding changed the conformation of suilysin, especially the angle between domain two and domain four, resulting in the disruption of cholesterol binding to suilysin and in the loss of pore-forming activity.

CONCLUSIONS

Formononetin is located at the junction of domain two and domain four of suilysin, and Y412 and N413 play critical roles in the binding. Formononetin binding changes the angle between domain two and domain four of suilysin, resulting in the loss of the pore-inducing activity of suilysin.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work will promote the application of formononetin to combat S. suis infections and may contribute to the development of new inhibitors or modification of existing inhibitors.

Myricetin inhibits the type III secretion system of Salmonella enterica serovar typhimurium by downregulating the Salmonella pathogenic island I gene regulatory pathway

Based on the in-depth study of type III secretion systems (T3SS) in pathogenic bacteria, approaches targeting T3SS have become new alternative strategies to combat drug-resistant bacterial infections. As an important food-borne pathogen, Salmonella enterica serovar Typhimurium (S. Typhimurium) injects effector proteins into host cells through the T3SS to disrupt cell signaling and host responses. In this study, myricetin was screened for its ability to block the translocation function of effector proteins (SipA/SipB) using cell biology and molecular biology methods. It exerted strong effects on inhibiting the expression of Salmonella pathogenicity island 1 (SPI-1)-associated effector proteins without affecting S. Typhimurium growth and thus prevented S. Typhimurium from invading HeLa cells and ultimately inhibited S. Typhimurium-mediated cell damage. In an animal experiment, myricetin comprehensively protected mice from death and pathological damage. A further analysis of the mechanism of action showed that myricetin interfered with the regulatory network of SPI-1-related genes, resulting in a significant decrease in the levels of key effector proteins, and thus inhibited T3SS-mediated virulence. In summary, this study provides a solution for clinical resistance to S. Typhimurium infection and potential candidate compounds. Myricetin, a potential T3SS inhibitor, possesses effective biological activity and exerts protective effects in vitro and in vivo. Myricetin will likely be developed as a novel type of antibiotic targeting S. Typhimurium infections in the future.

Influence of the Internet of Things management system on hand hygiene compliance in an emergency intensive care unit

BACKGROUND

Hand hygiene is a critical strategy for infection prevention in all healthcare settings. Automated electronic monitoring systems are expected to improve hand hygiene performance.

AIM

To investigate the impact of the Internet of Things (IoT) management system on hand hygiene compliance among medical staff in an emergency intensive care unit (EICU).

METHODS

This retrospective observational study was conducted between July 1^st, 2017 and February 28^th, 2018 in a 19-bed EICU. The changes in hand hygiene compliance among 54 members of medical staff and the incidence of hospital infections were compared, counted, and analysed before and after implementing the IoT management system in the EICU that was initiated on November 1^st, 2017.

FINDINGS

After the application of the IoT management system, the hand hygiene compliance rates among the members of the medical staff before (29.5% (3347/11,338) vs 57.9% (4690/8094), P < 0.001) and after (59.9% (9915/16,556) vs 73.8% (17,194/23 286), P < 0.001) the contact with patients and surrounding environment significantly improved. However, hand hygiene compliance among three cleaning staff did not significantly improve after the application. Moreover, there was no significant difference in healthcare-acquired infection rates (2.535% (9/355) vs 2.047% (7/342), P = 0.667) nor in the detection rates of the four major multidrug-resistant bacteria in the EICU before and after the application of the IoT management system (P > 0.05).

CONCLUSION

The IoT management system significantly improved hand hygiene compliance among medical staff, except cleaners, in the EICU of one provincial hospital; however, the rates of nosocomial infection did not significantly decrease. The quality of hand hygiene implementation needs to be improved.

MicroRNA-26b-5p promotes development of neonatal respiratory distress syndrome by inhibiting differentiation of mesenchymal stem cells to type II of alveolar epithelial cells via regulating Wnt5a

OBJECTIVE

The aim was to investigate the role of microRNA-26b-5p in regulating mesenchymal stem cells (MSCs) differentiation to type II of alveolar epithelial cells (AECII) in the disease course of neonatal respiratory distress syndrome (NRDS).

MATERIALS AND METHODS

MSCs were first derived from rat bone marrow. In vitro induction of MSCs differentiation to AECII was conducted by SAGM. The mRNA levels of microRNA-26b-5p, Wnt5a, and AECII-related genes (Occludin, KGF, CK18, SpA, SpB, and SpC) during the process of cell differentiation were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Enzyme-linked immunosorbent assay (ELISA) was conducted for detecting levels of inflammatory factors tumor necrosis factor-α (TNF-α), interferon-α (INF-α), and interleukin-1 (IL-1) in cell supernatant. Dual-luciferase reporter gene assay was then carried out to verify the regulatory effect of microRNA-26b-5p on Wnt5a. MicroRNA-26b-5p expression in serum samples of NRDS neonates and healthy neonates was detected by qRT-PCR as well.

RESULTS

MicroRNA-26b-5p was overexpressed in NRDS neonates than those of healthy neonates. Besides, microRNA-26b-5p was highly expressed in the process of MSCs differentiation to AECII. MicroRNA-26b-5p overexpression remarkably inhibited AECII differentiation and Wnt5a expression. Levels of TNF-α, INF-α, and IL-1 in cell supernatant during differentiation induction were elevated. The regulatory effects of microRNA-26b-5p on AECII differentiation, Wnt5a expression, and inflammatory response were reversed by Wnt5a overexpression.

CONCLUSIONS

MicroRNA-26b-5p inhibits MSCs differentiation to AECII via inhibiting Wnt5a expression through the Wnt pathway.

Tectorigenin reduces type IV pilus-dependent cell adherence in Clostridium perfringens

Clostridium perfringens is an anaerobic, Gram-positive bacterium that causes a range of diseases in humans and animals around the globe. The type IV pilus (TFP) system plays a key role in the colonization and invasion of host cells, biofilm formation and gliding motility, which is vital for C. perfringens infection. Therefore, targeting TFP function may be a promising strategy for the treatment of C. perfringens infection. Here, we investigated the potential inhibitory effects of tectorigenin (TE), an isoflavone extracted from the rhizome of the Chinese herb Belamcanda chinensis (L.) DC, on gliding motility, biofilm formation, adherence to cells and antibacterial activity of C. perfringens. Tectorigenin significantly inhibited gliding motility, biofilm formation and adherence to Caco-2 cells without observable antibacterial activity against C. perfringens. In addition, we also demonstrated that the inhibitory effect of TE on TFP function appears to be partially achieved by the suppression of TFP-associated genes. These findings demonstrate that TE may have the potential to be developed as a new anti-virulence drug for C. perfringens infection, particularly for the targeting of TFP.

AB0132 ALTERATIONS IN PERIPHERAL T-CELLS AND B-CELLS SUBSETS IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS AND SJÖGREN’S SYNDROME UNDERGOING THERAPEUTIC PLASMA EXCHANGE OR IMMUNOADSORPTION

Background:

Systemic lupus erythematosus (SLE) and Sjögren’s syndrome (SS) are systemic autoimmune diseases characterized by a broad spectrum of clinical manifestations and disease course. Alternative therapies such as therapeutic plasma exchange (TPE), immunoadsorption are recommended to the patients who lack a good response to standard therapy [1].

Objectives:

Our observational study was to explored whether abnormalities in T-cells, B-cells and their subtypes were present in the patients who had TPE or immunoadsorption in patients with SLE and SS compared with healthy controls (HC).

Methods:

Demographic, clinical variables and autoantibodies were recorded. Flow cytometry was used to establish the frequencies of lineage subsets. Monoclonal antibodies against 21 surface markers such as CD3, CD4, CD8, were used to distinguish and evaluate T-cells’ and B-cells’ subpopulation. SLE acvity was measured using systemic lupus erythematosus disease activity index (SLEDAI). Comparisons between subgroups were undertaken using paired T-test, Mann-Whitney U test and ANOVA.

Figure 1.

Altered expression of CD4+ T-cell subsets in the patients with SLE and SS after treated with plasma exchange or immunoadsorption

Results:

6 SS patients and 1 SLE patient underwent immune adsorption, while the other 5 SLE patients had plasma exchange all for three times. There was no significant difference among SLE, SS and HC in the proportion of T-cells and B-cells. The proportion of CD3-CD19+CD27+IgD+ B-cells were reduced in SLE, while CD3+CD4+CD25+CD127- T-cells were elevated in SS. The proportion of CD3+CD4+CD45RA+CCR7+T-cells were increased (p= 0.045), while CD3+CD4+CD25+CD127- T-cells were declined (p= 0.027) and CD3+CD4+CXCR5+PD-1+ T-cells went down after the therapies (p≤ 0.030). The proportion of CD3-CD19+IgD-IgM-CD27+CD38+ B-cells was also reduced after TPE or immunoadsorption (p= 0.032) with ANA titers and IgG decreasing dramatically. SLEDAI scores were reduced after the therapy in SLE patients.

Conclusion:

The T-cell and B-cell’s profiles were proved to have alteration after TPE or immunoadsorption which shed light on the complicated mechanisms of these relatively novel therapy in SLE and SS.

References:

[1]Bertsias GK, Tektonidou M, Amoura Z, et al. Joint European League Against Rheumatism and European Renal Association-European Dialysis and Transplant Association (EULAR/ERA-EDTA) recommendations for the management of adult and paediatric lupus nephritis. ANN RHEUM DIS 2012;71:1771-1782.

Acknowledgments:

None.

Disclosure of Interests:

None declared

AB0727 WORK OUTCOMES AND ASSOCIATED FACTORS IN ANKYLOSING SPONDYLITIS PATIENTS IN CHINA

Background:

Poorer work productivity due to pain and functional impairment is commonly seen in ankylosing spondylitis (AS) patients, which may contribute to huge social economic burden. However, data about work outcomes and associated factors in Chinese AS patients were barely reported.

Objectives:

To assess work outcomes and identify factors associated with poor work productivity in patients with AS in China.

Methods:

A cross-sectional study was conducted in China. Adult patients (aged ≥ 18 years) fulfilled the 1984 New York modified criteria of AS were enrolled from rheumatology center from Jan 2017 to Aug 2017. All participants completed questionnaires about socio-demographic characteristics, disease characteristics, quality of life and the Work productivity and activity impairment questionnaire in AS (WPAI:SpA) to accesses the impact of chronic health conditions on job performance and productivity. Factors associated with work outcomes were evaluated.

Results:

A total of 91 patients with AS were included: 87.8% males, 78.02% employed, mean age and disease duration of 30 and 10 years respectively. The mean (SD) activity impairment of all patients was 48.57% (22.02%). For patients with employed work, mean (SD) absenteeism, presenteeism and work productivity loss were 10.22% (19.44%), 43.86% (22.48%) and 47.92% (25.81%) respectively. In multivariable analysis, activity impairment was associated with Bath Ankylosing Spondylitis Functional Index (BASFI) (P<0.01) and Ankylosing Spondylitis Quality of Life (ASQoL) (P<0.01). Absenteeism was associated with disease duration (P=0.03). Presenteeism was associated with disease duration (P=0.04), BASFI (P<0.01) and ASQoL (P<0.01). Work productivity loss was associated with BASFI (P<0.01) and ASQoL (P<0.01).

Conclusion:

Longer disease duration, reduced physical function and poorer quality of life are associated with reduced work productivity in Chinese AS patients.

References:

[1]Boonen A, van der Heijde D, Landewe R, Spoorenberg A, Schouten H, Rutten-van Molken M, et al. Work status and productivity costs due to ankylosing spondylitis: comparison of three European countries. Annals of the rheumatic diseases. 2002;61(5):429-37.

[2]Martindale J, Shukla R, Goodacre J. The impact of ankylosing spondylitis/axial spondyloarthritis on work productivity. Best Pract Res Clin Rheumatol. 2015;29(3):512-23.

[3]Castillo-Ortiz JD, Ramiro S, Landewe R, van der Heijde D, Dougados M, van den Bosch F, et al. Work Outcome in Patients With Ankylosing Spondylitis: Results From a 12-Year Followup of an International Study. Arthritis Care Res (Hoboken). 2016;68(4):544-52.

[4]Sag S, Nas K, Sag MS, Tekeoglu I, Kamanli A. Relationship of work disability between the disease activity, depression and quality of life in patients with ankylosing spondylitis. J Back Musculoskelet Rehabil. 2018;31(3):499-505.

[5]Goh Y, Kwan YH, Leung YY, Fong W, Cheung PP. A cross-sectional study on factors associated with poor work outcomes in patients with axial spondyloarthritis in Singapore. Int J Rheum Dis. 2019;22(11):2001-8.

Disclosure of Interests:

None declared

AB0049 IMMUNE DYSFUNCTION IN ANKYLOSING SPONDYLITIS (AS) AND THE POTENTIAL OF TUMOR NECROSIS FACTOR-Α (TNF-α) INHIBITOR ANBAINUO AS AN EFFECTIVE TREATMENT

Background:

Studies into ankylosing spondylitis (AS) and its relationship with immune function are controversial, and the correlation between the efficacy of TNF-α inhibitor and changes in immune function is unclear.

Objectives:

We conducted a prospective study of T-cell and B-cell subset distribution and analyzed lymphocyte function in AS patients to further clarify changes to the immune system caused by AS and to explore resistance that could contribute to relapse after treatment.

Methods:

A total of 40 immune cells were tested with flow cytometry, and the results of 105 HC (healthy control) subjects, 177 active-stage AS patients, and 23 AS cases before and after 12 weeks of Anbainuo therapy were analyzed.

Results:

Compared with the HC group, the proportion of immune cells, such as naïve and central memory CD4+T cells, in AS increased (p<0.0001), but effector memory and terminally differentiated CD4+T cells were decreased (p<0.01 and 0.0001, respectively). Naïve, central memory, and effector memory CD8+T cells were increased (p<0.0001, 0.001, and 0.01, respectively), but terminally differentiated CD8+T cells were decreased (p<0.0001). Th1 cells (helper T cells-1), Tfh1 cells (follicular helper T cells-1), Tc1 cells (cytotoxic T cells-1), and Tregs (regulatory T cells) were lower (p<0.01, 0.05, 0.0001, and 0.001, respectively), but Th17 cells, Tfh17 cells, and Tc cells were higher (p<0.001, 0.0001 and 0.001, respectively). The proportions of total B cells and class-switched B cells were increased (p<0.05), but non-switched B cells, plasma cells, memory B cells, and immature Bregs (regulatory B cells) were lower (p<0.01, 0.0001, 0.0001, and 0.0001, respectively). After Anbainuo therapy, the percentage of Tregs and B10 cells (IL-10-producing regulatory B cells) had increased (p<0.01and 0.05, respectively), and the increase in Tregs was positively correlated with the decrease in CRP (C-reactive protein) (r= 0.489, p=0.018).

Conclusion:

We found that, in terms of both innate and acquired immunity, active-stage AS patients have an immunity imbalance involving multiple types of immune cells, including CD4+T cells, CD8+T cells, Th cells, Tfh cells, Tc cells, Tregs, Bregs, and B cells. Anbainuo can not only help to inhibit disease activity and partial immune function imbalance in AS but can also increase the number of negative regulatory cells in inflammation.

References:

[1]Long, S., et al., High frequency of circulating follicular helper T cells is correlated with B cell subtypes in patients with ankylosing spondylitis. Exp Ther Med, 2018. 15(5): p. 4578-4586.

[2]An, H., et al., The absolute counts of peripheral T lymphocyte subsets in patient with ankylosing spondylitis and the effect of low-dose interleukin-2. Medicine (Baltimore), 2019. 98(15): p. e15094.

Acknowledgments:

Thanks to Professor Zhinan Yin for his support and assistance with this study

Disclosure of Interests:

None declared

0638 Evaluation of an Oral Drug Pyridostigmine Bromide in Patients with Mild to Moderate Obstructive Sleep Apnea

Introduction

A randomized, double-blind, cross-over, placebo-controlled clinical study with pyridostigmine bromide (PYD) in obstructive sleep apnea (OSA) patients ranging from mild to moderate disease was conducted to evaluate its clinical efficacy and safety.

Methods

Six diagnosed male patients with averages of age 48 yr (38 - 57 yr), BMI 28 (26 - 33), AHI 19.2 (15 - 26.2), minimum oxygen saturation (Min SaO2) 81% (75 - 87%) were enrolled to the study. The study consisted one-night acclimatization period followed immediately by a 2-night double-blind treatment period when subjects received either a single dose of PYD (a cholinesterase inhibitor, 90 mg) or placebo before sleep. Subjects were required to maintain in a supine position, and monitored by a standard polysomnography all the time. Sleep questionnaires (The SMH Sleep Questionnaire and ESS) were taken daily immediately after sleep and at the evening to evaluate the sleep satisfaction and the day-time quality, respectively. Safety of the drug was monitored and evaluated.

Results

Reductions of AHI (28.1%, p &lt; 0.01), apnea index (37.2%, p &lt; 0.05), % of total apnea/hypopnea time (36.4%, p &lt; 0.05) were observed in the treatment group compared with the placebo between 2-7 hours of sleep. Min SaO2 was increased, no change, or decreased by PYD in 3, 2, or 1 subject(s), respectively. PYD was generally well tolerated with minimum minor incidents. Subjects reported to have more satisfied sleep and more clear-headed in the treatment night, and more energy, more concentrated and less sleepy during the daytime following the treatment night.

Conclusion

This study demonstrated the initial effectiveness of the PYD treatment for OSA, indicating that it may provide a new treatment option if the efficacy can be maintained in a large-scale clinical trial.

Support

N/A

Acacetin inhibits Streptococcus pneumoniae virulence by targeting pneumolysin

OBJECTIVES

Streptococcus pneumoniae (S. pneumoniae) is an important commensal and pathogenic bacterium responsible for pneumonia, meningitis and other invasive diseases. Pneumolysin (PLY) is the major virulence factor that contributes significantly to the interaction between S. pneumoniae and the host.

KEY FINDINGS

In this study, the results of antibacterial analysis, the haemolysis test and the Western blotting assay showed that acacetin inhibited PLY-mediated pore-forming activity caused by S. pneumoniae culture precipitates and purified PLY without anti-S. pneumoniae activity. In addition, acacetin treatment inhibited PLY oligomerization without affecting the expression of PLY in S. pneumoniae culture supernatants. Live/dead cells and cytotoxicity assays suggested that acacetin significantly enhanced the survival rate of injured cells by inhibiting the biological toxicity of PLY without cytotoxicity in the coculture system. The in vivo mouse model of S. pneumoniae infection further demonstrated that acacetin treatment could significantly reduce the levels of inflammatory factors (INF-γ and IL-β) in bronchoalveolar lavage fluid (BALF) and alleviate the pathological damage of lung injury.

CONCLUSIONS

Taken together, the results presented in this study indicated that acacetin inhibited the pore-forming activity of PLY and reduced the virulence of S. pneumoniae in vivo and in vitro, which may provide a leading compound for the treatment of S. pneumoniae infection.

Isoalantolactone restores the sensitivity of gram-negative Enterobacteriaceae carrying MCR-1 to carbapenems

Polymyxin B has been re‐applied to the clinic as the final choice for the treatment of multidrug‐resistant gram‐negative pathogenic infections, but the use of polymyxin B has been re‐assessed because of the emergence and spread of the plasmid‐mediated mcr‐1 gene. The purpose of this study was to search for an MCR inhibitor synergistically acting with polymyxin to treat the infection caused by this pathogen. In this study, we used the broth microdilution checkerboard method to evaluate the synergistic effect of isoalantolactone (IAL) and polymyxin B on mcr‐1‐positive Enterobacteriaceae. Growth curve analysis, time‐killing assays and a combined disc test were used to further verify the efficacy of the combined drug. Colonization of the thigh muscle in mice, survival experiments and lung tissue section observations was used to determine the effect of synergy in vivo after Klebsiella pneumoniae and Escherichia coli infection. We screened a natural compound, IAL, which can enhance the sensitivity of polymyxin B to mcr‐1‐positive Enterobacteriaceae. The results showed that the combined use of polymyxin B and IAL has a synergistic effect on mcr‐1‐positive Enterobacteriaceae, such as K pneumoniae and E coli, not only in vitro but also in vivo. Our results indicate that IAL is a natural compound with broad application prospects that can prolong the service life of polymyxin B and make outstanding contributions to the treatment of gram‐negative Enterobacteriaceae infections resistant to polymyxin B.

Identification of the natural product paeonol derived from peony bark as an inhibitor of the Salmonella enterica serovar Typhimurium type III secretion system

Salmonella enterica serovar Typhimurium (S. Typhimurium) is an important zoonotic pathogen in public health and food safety. The type III secretion system (T3SS) encoded by Salmonella pathogenicity island (SPI) is a sophisticated molecular machine that facilitates active invasion, intracellular replication, and host inflammation. Due to increasing antibiotic resistance, new therapeutic strategies that target the Salmonella T3SS have received considerable attention. In this study, paeonol was identified as an inhibitor of the S. Typhimurium T3SS. Paeonol significantly blocked the translocation of SipA into host cells and suppressed the expression of effector proteins without affecting bacterial growth in the effective concentration range. Additionally, S. Typhimurium-mediated cell injury and invasion levels were significantly reduced after treatment with paeonol, without cytotoxicity. Most importantly, the comprehensive protective effect of paeonol was confirmed in an S. Typhimurium mouse infection model. Preliminary mechanistic studies suggest that paeonol inhibits the expression of effector proteins by reducing the transcription level of the SPI-1 regulatory pathway gene hilA. This work provides proof that paeonol could be used as a potential drug to treat infections caused by Salmonella.

Quercetin, a pneumolysin inhibitor, protects mice against Streptococcus pneumoniae infection

Pneumolysin (PLY), a pore-forming cytotoxin and a major virulence determinant, is a member of the cholesterol-dependent cytolysin (CDC) family and essential for promoting Streptococcus pneumoniae (S.pneumoniae) infection. Due to the action characteristics of hemolysin itself, the pneumolysin released after killing bacteria with conventional antibiotics still has the ability to damage host cells; therefore, drug treatments directly inhibiting hemolysin activity are the most effective. Hemolysis assays were used to confirm that quercetin can inhibit the activity of PLY, protecting cells in vitro, and an oligomerization assay was used to determine the mechanism of quercetin to suppress PLY activity. Live/Dead testing, lactate dehydrogenase (LDH) release analysis and a murine model of endonasal pulmonary infection were used to explore the capability of quercetin to protect cells and mice from S. pneumoniae-mediated damage in vivo and in vitro. The results indicated that quercetin significantly reduced PLY-induced hemolytic activity and cytotoxicity via repressing the formation of oligomers. In addition, treatment with quercetin can reduce PLY-mediated cell injury, improve the survival rate of mice infected with a lethal dose of S. pneumoniae, alleviate the pathological damage of lung tissue and inhibit the release of cytokines (IL-1β and TNF-α) in bronchoalveolar lavage fluid. Considering the importance of these events in antimicrobial resistant S. pneumoniae pathogenesis, our results indicated that quercetin may be a novel potential drug candidate for the treatment of clinical pneumococcal infections.

Expression of sodium/iodide transporters and thyroid stimulating hormone receptors in thyroid cancer patients and its correlation with iodine nutrition status and pathology

OBJECTIVE

To investigate the relationship between the expression of sodium/iodide transporter (NIS) and thyroid stimulating hormone receptor (TSHR) and iodine nutritional status in patients with thyroid carcinoma.

PATIENTS AND METHODS

146 cases of thyroid cancer in Shanghai Gongli Hospital, the Second Military Medical University between February and December 2014 were selected as thyroid cancer group, 120 cases of normal thyroid morphology examined by thyroid ultrasound at the same period were selected as normal group. General information and thyroid function of two groups were recorded and analyzed. H&E staining was used to perform histopathological study on both normal group and thyroid cancer group, and immunohistochemistry was used to detect NIS and TSHR protein expression and position. Reverse transcriptase polymerase chain reaction (RT-PCR) was used for quantitative detection of NIS and TSHR mRNA in the two groups, and the relationship between iodine nutrition and NIS and TSHR expression in thyroid cancer patients was studied. The expression of NIS and TSHR in each group was detected by Western blotting, and the difference in NIS and TSHR expression was analyzed by SPSS 17.0 statistical software.

RESULTS

The difference of serum total triiodothyronine (TT3), total thyroxine (TT4), and thyroid stimulating hormone (TSH) levels between the normal group and the thyroid cancer group was statistically significant (p < 0.05). H&E staining showed that the histopathology of the thyroid cancer group was significantly different from that of the normal group. Immunohistochemistry showed the positive expression of NIS and TSHR in thyroid cancer group. The expression of NIS and TSHR mRNA and protein in thyroid cancer patients was significantly lower than that in normal group detected by RT-PCR and Western blotting. Analysis of variance showed that the difference of NIS and TSHR expression between the two groups was statistically significant (p < 0.05).

CONCLUSIONS

These findings indicated that the expression of NIS and TSHR in thyroid cancer is closely related to iodine nutritional status, which has important research value.

Inhibition of the type III secretion system by syringaldehyde protects mice from Salmonella enterica serovar Typhimurium

The invasiveness of Salmonella enterica serovar Typhimurium (S. Typhimurium) is closely associated with the Salmonella pathogenicity island (SPI)‐encoded type Ⅲ secretion system (T3SS), which can directly inject a series of effector proteins into eukaryotic cells to enable bacterial infection. In this study, syringaldehyde was identified as an effective inhibitor of the S. Typhimurium T3SS using an effector protein‐lactamase fusion reporter system. Syringaldehyde treatment could inhibit the expression of important effector proteins (SipA, SipB and SipC) at a concentration of 0.18 mM without affecting bacterial growth. Additionally, significant inhibition of bacterial invasion and cellular injury was observed following the syringaldehyde treatment in the co‐infection system of HeLa cells and S. Typhimurium. Furthermore, treatment with syringaldehyde provided systemic protection to mice infected with S. Typhimurium, reducing mortality (40.00%) and bacterial loads and relieving caecal damage and systemic inflammation. The results presented in this study indicate that syringaldehyde significantly affects T3SS activity and is a potential leading compound for treating S. Typhimurium infections.

Curcumin attenuates palmitic acid-induced cell apoptosis by inhibiting endoplasmic reticulum stress in H9C2 cardiomyocytes

Diabetic cardiomyopathy is mediated by multiple molecular mechanisms including endoplasmic reticulum (ER) stress. Curcumin, a phenolic compound, has cytoprotective properties, but its potential protective action against diabetic cardiomyopathy and the related molecular mechanisms are not fully elucidated. In this study, we evaluated the effects of curcumin on cell viability and apoptosis in palmitic acid (PA)-treated H9C2 cardiomyocytes and investigated the signaling pathways involved. Treatment with PA reduced cell viability, induced apoptosis, enhanced apoptosis-related protein expression (Caspase 3 and BCL-2 associated X protein (BAX)), and activated ER stress marker protein expression (glucose-regulated protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP)). Curcumin attenuated PA-induced reduction in cell viability and activation of apoptosis, Caspase 3 activity, BAX, CHOP, and GRP78 expression. 4-Phenylbutyric acid (4-PBA) attenuated the PA-induced effects on cell viability and apoptosis, similar to curcumin. Both curcumin and 4-PBA also attenuated PA-induced increase in ER stress protein (CHOP and GRP78) expression. Curcumin also protected against cytotoxicity, apoptosis, and ER stress induced by thapsigargin. These findings indicate that PA triggers apoptosis in H9C2 cells via ER stress pathways and curcumin protects against this phenomenon.

Association of VDR and OPG gene polymorphism with osteoporosis risk in Chinese postmenopausal women

AIMS

The underlying mechanisms of vitamin D receptor (VDR) and osteoprotegerin (OPG) genetic variation associated with bone mineral density and osteoporosis remain uncertain. This study aimed to investigate the association of VDR and OPG gene polymorphism as well as gene-gene interaction and their haplotype combination with the risk of osteoporosis.

METHODS

Polymerase chain reaction restriction fragment length polymorphism was carried out for single nucleotide polymorphism (SNP) detection. Generalized multifactor dimension reduction (GMDR) is used to identify the interaction. SHEsis software evaluated the haplotype and logistic regression was performed to assess the association between the SNPs within the VDR and OPG genes and osteoporosis.

RESULTS

The risk of osteoporosis in the VDR-rs2228570 polymorphism T-allele carriers was significantly higher than that in CC (CT/TT versus CC) individuals (adjusted odds ratio [OR] [95% confidence interval (CI)] = 1.76 [1.33-2.22]). The risk of osteoporosis was also higher in the G-allele carrier of the OPG-rs3102735 polymorphism than in individuals with the AA genotype (AG/GG vs. AA) (adjusted OR [95% CI] = 1.65 [1.27-2.14]). However, after adjusting for sex, age, and waist circumference covariates, no significant association of VDR-rs17879735 and OPG-rs2073618 with the osteoporosis risk was revealed. The GMDR method identified that gene-gene interactions were significant, but not for gene/AO interaction. Haplotypes were analyzed with SHEsis software. We did not detect a high-risk haplotype combination associated with osteoporosis.

CONCLUSIONS

Both VDR-rs2228570-T and OPG-rs3102735-G and their interactions are related to the increased risk of osteoporosis.

Effect of developmental stage of embryos at freezing on live birth outcomes after frozen embryo transfer

　　Purpose Our objective was to evaluate the birth outcomes of FET from different developmental stage of embryo at freezing (Day 3, Day 5 and Day 6). Methods All vitrified-warmed day 3 (D3) and day 5/6 (D5, D6) embryo transfers during the time period from January 2013 until December 2015 were included in the study. The Birthweight, Low birthweight (LBW), sexual distinction, gestation and for singleton births and twins conceived by FET were compared retrospectively between three cryopreservation strategies utilizing either D3, D5 or D6 embryo freezing. All embryos were vitrified by Dimethylsulfoxide (DMSO), Ethylene glycol (EG) and Sucrose used as Cryoprotectants and using Cryoleaf as the receptacles. Results A total of 993 infants from 771 women. The length of embryos storage was 3-38 months, with a median of 8 months. For singleton, birthweight from D5 and D6 blastocysts transfers were significantly heavier than for D3 cleavage-stage embryos transfers (P =0.0065 P =0.0006). For twins, birthweight from D6 blastocysts transfers were significantly heavier than for D5 blastocysts transfers (P =0.0044), and children born after D3 were at a signigicantly increased risk of being born a LBW. Conclusions Birthweights from FET are influenced by developmental stage of embryos at freezing, which were lower for cleavage-stage embryos transfer than blastocysts transfer after FET in singletons. The birth rate of LBW infants was higher in the twins. The study was small so there may be other factors than cryopreservation which affected outcomes. A higher sample size or a multi-centre prospective randomized design could be used in future studies to corroborate the current findings.

Construction of recombinant adenovirus Ad-rat PLCγ2 and its effects on apoptosis of rat liver cell BRL-3A in vitro

Although the role of PLCγ2 in apoptotic response has been reported, too little is known about whether PLCγ2 induces liver cell apoptosis during liver regeneration. Therefore, this study firstly packaged Ad-PLCγ2 recombinant adenovirus and primarily evaluated its effect on apoptosis of rat liver cell BRL-3A in vitro. Following ten days of co-transfection of pHBAd-MCMV-GFP-PLCγ2 and pHBAd-BHG into HEK293 cells, viral cytopathic effect (CPE) was apparent. Following three rounds of amplification, tissue culture infectious dose 50 (TCID50) assay showed that the titer value reached 1×1010 PFU/mL. After 24 h of transfection of recombinant adenovirus into BRL-3A cells, transfection efficiency of adenovirus into BRL-3A cells was above 90% when obsereved under fluorescent microscopy. qRT-PCR and Western blot assays showed mRNA and protein levels of PLCγ2 were significantly elevated in the transfected BRL-3A cells. Flow cytometric analysis showed that, compared with the control and Ad-GFP groups, cell apoptosis rate of Ad-PLCγ2 group were significantly increased (P<0.01), and the cell cycle in Ad-PLCγ2 group was arrested at G1 phase which was manifested by a marked increase (P<0.01) in the percentage of G1 phase cells and a great decrease (P<0.01) in the percentage of S and G2/M phase cells. It was concluded from above results that recombinant adenovirus Ad-PLCγ2 was packaged successfully, and could promote cell apoptosis by arresting the transition from G1 to S phase of BRL-3A cells.

Glucocorticoid combined with hyaluronic acid enhance glucocorticoid receptor activity through inhibiting p-38MAPK signal pathway activation in treating acute lung injury in rats

OBJECTIVE

In order to seek an effective strategy for clinical treatment of acute lung injury (ALI), we are committed to explore the effect of combination therapy of glucocorticoid and hyaluronic acid on acute lung injury caused by an endotoxin (LPS) and its mechanism.

MATERIALS AND METHODS

Adult male Sprague-Dawley (SD) rats were divided randomly into 5 groups: normal group (n=8); LPS group (n=8); dexamethasone +LPS group (DXMS group, n=8); hyaluronic acid+ LPS group (HA group, n=8); dexamethasone +hyaluronic acid +LPS group (DXMS+HA group, n=8). Firstly, SD rat model with acute lung injury induced by LPS was established, and injected corresponding drugs according to the plan. Then, the expression of TNF-a, IL-8, IL-10, ICAM-1 and total protein were measured by ELISA, and the HE staining was used for detected the pathological change in lung tissue. Subsequently, the water content, dry and wet ratio and permeability in lung tissues of SD rats was assayed. Finally, the expression level of the glucocorticoid receptor (GR) was detected by RT-PCR, and activation of p-p38MAPK was determined by Western blotting.

RESULTS

The results showed that concentration of IL-8, IL-10 and ICAM-1 was significantly increased in BALF after LPS injection, and the results from HE staining showed it had widespread inflammation. However, lung structures in SD rats with inhalation lung injury were improved significantly after the injection of dexamethasone and hyaluronic acid, and the Pa02/Fi02, blood pressure and Cdyn were also increased. Moreover, lung water content, the ratio of wet and dry lung, and lung permeability index (LPI) was decreased after having treated the SD rats with a combination of dexamethasone and hyaluronic acid, and the apoptosis index was also decreased in the rats with LPS-induced ALI. Our data also suggested that TNF-α, IL-8, IL-10, intercellular cell adhesion molecule-1 (ICAM-1) and total protein was significantly declined in bronchoalveolar lavage fluid (BALF) of rats with LPS-induced acute lung injury after treated the SD rats with a combination of dexamethasone and hyaluronic acid. In addition, the data also implied that anti-inflammatory effect by inhibiting the activation of p38MAPK signal pathway induced by LPS through enhancement of the activity of GR, to further analyze the mechanism of the effect of combination therapy with dexamethasone and hyaluronic acid on acute lung injury in SD rats.

CONCLUSIONS

LPS-induced ALI in SD rats is relieved after treatment with a combination of dexamethasone and hyaluronic acid. In the process of its function, activated GR can represent anti-inflammatory effect and protect the lung tissue by inhibiting the activation/phosphorylation of p38MAPK, while hyaluronic acid can enhance micro-environment of alveolar tissue.

A Novel Poly(L-lactide) (PLLA)/Fibroin Hybrid Scaffold to Promote Hepatocyte Viability and Decrease Macrophage Responses

The purpose of this study was to evaluate the hepatocellular compatibility and assess the inflammatory response of a novel hybrid scaffold of poly(L-lactide) (PLLA) and fibroin. The hybrid scaffold was obtained by freezing and lyophilizing a blend of fibroin microspheres and PLLA solution. FTIR and scanning electron microscopy (SEM) analysis indicated that fibroin microspheres were on the surface of the hybrid scaffold. Compared to the PLLA scaffold, SEM and laser scanning confocal microscope (LSCM) analyses showed that the human hepatocellular carcinoma HepG2 cells had spread and proliferated much more in the hybrid scaffold. The MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assays indicated a greater number of cells in this hybrid scaffold. Furthermore, a mouse RAW264.7 macrophages cell line was utilized to characterize and compare the mRNA profiles of TNF-alpha using real time-polymerase chain reaction (RT-PCR). The inflammatory response of the macrophages grown in the PLLA/fibroin scaffold rapidly declined compared to those in the PLLA scaffold and reached the level of cells grown in Dulbecco's Modified Eagle Medium (DMEM). The hepatocellular compatibility and lower level of inflammatory response makes the PLLA/fibroin scaffold a promising candidate for hepatic tissue engineering.

Biocompatible Fibroin Blended Films with Recombinant Human-like Collagen for Hepatic Tissue Engineering

Recombinant human-like collagen (RHLC) was blended with fibroin to prepare a novel biocompatible film as a scaffold material for hepatic tissue engineering applications. Solution blending was used to incorporate RHLC with silk fibroin to enhance the blend films biocompatibility and hydrophilicity while maintaining elasticity. FTIR and XRD analysis indicated that hydrogen bonds had formed between fibroin and RHLC, while SEM microscopy data confirmed that homogeneous microstructures were still retained after the introduction of RHLC with fibroin. Contact angle measurements indicated that the hydrophilicity of the fibroin/RHLC films was greater after RHLC was added. The elongation at break in the wet state was not markedly changed after blending the recombinant human-like collagen, which implied that flexibility was maintained. The proliferation and viability of the cell cultures on fibroin/RHLC films were significantly enhanced compared to pure fibroin films or tissue culture plates.