All-Trans Retinoic Acid Enhances Bacterial Flagellin-Stimulated Proinflammatory Responses in Human Monocyte THP-1 Cells by Upregulating CD14

Retinoic acid generates a beneficial microenvironment for liver progenitor cell activation in acute liver failure

BACKGROUND

When massive necrosis occurs in acute liver failure (ALF), rapid expansion of HSCs called liver progenitor cells (LPCs) in a process called ductular reaction is required for survival. The underlying mechanisms governing this process are not entirely known to date. In ALF, high levels of retinoic acid (RA), a molecule known for its pleiotropic roles in embryonic development, are secreted by activated HSCs. We hypothesized that RA plays a key role in ductular reaction during ALF.

METHODS

RNAseq was performed to identify molecular signaling pathways affected by all-trans retinoid acid (atRA) treatment in HepaRG LPCs. Functional assays were performed in HepaRG cells treated with atRA or cocultured with LX-2 cells and in the liver tissue of patients suffering from ALF.

RESULTS

Under ALF conditions, activated HSCs secreted RA, inducing RARα nuclear translocation in LPCs. RNAseq data and investigations in HepaRG cells revealed that atRA treatment activated the WNT-β-Catenin pathway, enhanced stemness genes (SOX9, AFP, and others), increased energy storage, and elevated the expression of ATP-binding cassette transporters in a RARα nuclear translocation-dependent manner. Further, atRA treatment-induced pathways were confirmed in a coculture system of HepaRG with LX-2 cells. Patients suffering from ALF who displayed RARα nuclear translocation in the LPCs had significantly better MELD scores than those without.

CONCLUSIONS

During ALF, RA secreted by activated HSCs promotes LPC activation, a prerequisite for subsequent LPC-mediated liver regeneration.

Detection and characterization of free oxygen radicals induced protein adduct formation in differentiating macrophages

Reactive oxygen species play a key role in cellular homeostasis and redox signaling at physiological levels, where excessive production affects the function and integrity of macromolecules, specifically proteins. Therefore, it is important to define radical-mediated proteotoxic stress in macrophages and identify target protein to prevent tissue dysfunction. A well employed, THP-1 cell line was utilized as in vitro model to study immune response and herein we employ immuno-spin trapping technique to investigate radical-mediated protein oxidation in macrophages. Hydroxyl radical formation along macrophage differentiation was confirmed by electron paramagnetic resonance along with confocal laser scanning microscopy using hydroxyphenyl fluorescein. Lipid peroxidation product, malondialdehyde, generated under experimental conditions as detected using swallow-tailed perylene derivative fluorescence observed by confocal laser scanning microscopy and high-performance liquid chromatography, respectively. The results obtained from this study warrant further corroboration and study of specific proteins involved in the macrophage activation and their role in inflammations.

Cell Surface Hsp90- and αMβ2 Integrin-Mediated Uptake of Bacterial Flagellins to Activate Inflammasomes by Human Macrophages

All-trans retinoic acid (ATRA) is an active metabolite of vitamin A, which plays an important role in the immune function. Here, we demonstrated that ATRA induces the heat shock protein (Hsp) 90 complex on the surface of THP-1 macrophages, which facilitates the internalization of exogenous bacterial flagellins to activate the inflammasome response. Mass spectrometric protein identification and co-immunoprecipitation revealed that the Hsp90 homodimer interacts with both Hsp70 and αMβ2 integrin. ATRA-induced complex formation was dependent on the retinoic acid receptor (RAR)/retinoid X receptor (RXR) pathway and intracellular calcium level and was essential for triggering the internalization of bacterial flagellin, which was clathrin dependent. Notably, in this process, αMβ2 integrin was found to act as a carrier to deliver flagellin to the cytosol to activate the inflammasome, leading to caspase-1 activity and secretion of interleukin (IL)-1β. Our study provides new insights into the underlying molecular mechanism by which exogenous bacterial flagellins are delivered into host cells without a bacterial transport system, as well as the mechanism by which vitamin A contributes to enhancing the human macrophage function to detect and respond to bacterial infection.

Earlier or heavier spinal loading is more likely to lead to recurrent lumbar disc herniation after percutaneous endoscopic lumbar discectomy

PURPOSE

To evaluate the clinical features of and risk factors for recurrent lumbar disc herniation (rLDH) after percutaneous endoscopic lumbar discectomy (PELD) in our clinical practice.

METHODS

A total of 942 consecutive patients who underwent single-level PELD from January 2013 to August 2019 were included. Patients were divided into the recurrence group and the nonrecurrence group. Patient characteristics, radiographic parameters and surgical variables were compared between the two groups. Univariate analysis and multiple logistic regression analysis were adopted to determine the risk factors for recurrence after PELD.

RESULTS

The prevalence of rLDH was 6.05%. Age, sex, tobacco use, duration of low back pain, body mass index (BMI), occupational lifting, herniated disc type, facet joint degeneration, operation time and time to ambulation were significantly different between the two groups. Univariate analysis showed that age (P < 0.001), sex (P = 0.019), BMI (P = 0.001), current smoking (P < 0.001), occupational lifting (P < 0.001), facet joint degeneration (P = 0.001), operation time (P = 0.002), and time to ambulation (P < 0.001) could be significantly associated with the incidence of rLDH after PELD. Multivariate analysis suggested that an older age (P < 0.001), the male sex (P = 0.017), a high BMI (P < 0.001), heavy work (P = 0.003), grade II facet joint degeneration (P < 0.001) and early ambulation (P < 0.001) were significantly related to rLDH after PELD.

CONCLUSIONS

An older age, the male sex, a higher BMI, heavy work, grade II facet joint degeneration, and early ambulation are independent significant risk factors for rLDH after PELD. Great importance should be attached to these risk factors to prevent rLDH. We suggest that patients control their weight, avoid heavy work, ambulate at an appropriate time, and perform strengthening rehabilitation exercises to reduce the incidence of rLDH.

Fibronectin Functions as a Selective Agonist for Distinct Toll-like Receptors in Triple-Negative Breast Cancer

The microenvironment of tumors is characterized by structural changes in the fibronectin matrix, which include increased deposition of the EDA isoform of fibronectin and the unfolding of the fibronectin Type III domains. The impact of these structural changes on tumor progression is not well understood. The fibronectin EDA (FnEDA) domain and the partially unfolded first Type III domain of fibronectin (FnIII-1c) have been identified as endogenous damage-associated molecular pattern molecules (DAMPs), which induce innate immune responses by serving as agonists for Toll-Like Receptors (TLRs). Using two triple-negative breast cancer (TNBC) cell lines MDA-MB-468 and MDA-MB-231, we show that FnEDA and FnIII-1c induce the pro-tumorigenic cytokine, IL-8, by serving as agonists for TLR5 and TLR2, the canonical receptors for bacterial flagellin and lipoprotein, respectively. We also find that FnIII-1c is not recognized by MDA-MB-468 cells but is recognized by MDA-MB-231 cells, suggesting a cell type rather than ligand specific utilization of TLRs. As IL-8 plays a major role in the progression of TNBC, these studies suggest that tumor-induced structural changes in the fibronectin matrix promote an inflammatory microenvironment conducive to metastatic progression.

High diversity of blaNDM-1-encoding plasmids in Klebsiella pneumoniae isolated from neonates in a Vietnamese hospital

OBJECTIVES

The carbapenemase-encoding gene bla_NDM-1 has been reported in Vietnam over the last ten years, and bla_NDM-producing Enterobacteriaceae are now silently and rapidly spreading. A key factor behind dissemination of bla_NDM-1 are plasmids, mobile genetic elements that commonly carry antibiotic resistance genes and spread via conjugation. Here, we characterized the diversity of bla_NDM-1-encoding plasmids from neonates at a large Vietnamese hospital .

METHODS

18 fecal Klebsiella pneumoniae and Klebsiella quasipneumoniae isolates collected from 16 neonates at a large pediatric hospital in Vietnam were studied with optical DNA mapping (ODM) and next-generation sequencing (NGS). We identified the plasmid(s) carrying bla_NDM-1 by combining ODM with Cas9 restriction. By comparing the plasmids between isolates, we could investigate if the same plasmid was present in different patients.

RESULTS

Although the same plasmid was found among some isolates, ODM confirmed that there were at least 10 different plasmids encoding bla_NDM-1 among the 18 isolates collected from 16 neonates, suggesting a large plasmid diversity. The ODM results were in large agreement with the NGS data. Interestingly, some isolates had two distinct plasmids encoding bla_NDM-1, which could be readily detected with ODM. Thus far, the coexistence of different plasmids carrying the same carbapenem resistance gene in an isolate encoding bla_NDM-1 has rarely been reported, likely due to limitations in existing plasmid characterization techniques.

CONCLUSIONS

Our results show that the plasmids encoding bla_NDM-1 in this cohort were very diverse, suggesting a similar picture in the Vietnamese society. The study also highlights important aspects of the usefulness of ODM for plasmid analysis.

Human Glioma Cells Therapy Using ATRA-Induced Differentiation Method to Promote the Inhibitive Effect of TMZ and CCDP

The glioma stem cells (GSCs) performed the self-renewal, proliferation, and differentiation characteristics; their drug resistance has become the main reason for glioma clinical treatment failure. All-trans retinoic acid (ATRA) is an important inducer of cell differentiation, applied in the treatment of hematologic diseases and other solid tumors. ATRA is a fat-soluble compound, which can easily go through the blood-brain barrier. Therefore, in this study, ATRA was used to induce the differentiation of glioma cells and glioma stem cells, reducing the degree of malignancy and improving its chemotherapy resistance. Methods and Treatment. The results of IF and PCR showed that the expression of CD133 was significantly lower than those of undifferentiated cells. Furthermore, temozolomide (TMZ) and cisplatin (CDDP), the first-line drugs, were used for the treatment of GCs and GSCs. The MTT assay results showed that the effect of the combination of the two drugs was significantly stronger than that of one of them alone. Results. Moreover, the MTT assay also demonstrated that TMZ single, CDDP single, and the combination of TMZ and CDDP can inhibit the proliferation of GCs, ATRA-GCs, GSCs, and ATRA-GSCs in a dose- and time-dependent manner; and ATRA-induced differentiation could promote those drugs inhibition effect and increased the chemotherapy sensitivity. Conclusion. Therefore, we successfully purified the suspension spherical glioma stem cells. Moreover, ATRA was demonstrated to induce the differentiation of GCs and GSCs. Furthermore, ATRA-induced differentiation promotes the inhibitive effect of TMZ and CCDP treatment on the proliferation of primary human glioma cells and glioma stem cells, suggesting that ATRA could increase the chemotherapy sensitivity of TMZ and CCDP through inducing cell differentiation. The combination of TMZ and CCDP performed a synergistic role in inhibiting the proliferation of GCs and GSCs.

The role of the retinoid receptor, RAR/RXR heterodimer, in liver physiology

Activated by retinoids, metabolites of vitamin A, the retinoic acid receptors (RARs) and the retinoid X receptors (RXRs) play important roles in a wide variety of biological processes, including embryo development, homeostasis, cell proliferation, differentiation and death. In this review, we summarized the functional roles of nuclear receptor RAR/RXR heterodimers in liver physiology. Specifically, RAR/RXR modulate the synthesis and metabolism of lipids and bile acids in hepatocytes, regulate cholesterol transport in macrophages, and repress fibrogenesis in hepatic stellate cells. We have also listed the specific genes that carry these functions and how RAR/RXR regulate their expression in liver cells, providing a mechanistic view of their roles in liver physiology. Meanwhile, we pointed out many questions regarding the detailed signaling of RAR/RXR in regulating the expression of liver genes, and hope future studies will address these issues.

Analysis of trending topics in glaucoma articles from an altmetric perspective

PURPOSE

Altmetric analyses are a new way of assessing and sharing scientific knowledge. Traditional metrics and altmetric analyses highlight key publications. The primary objective of this study was to evaluate the social attention paid to highly cited articles related to glaucoma in the recent English literature and compare with traditional citation metrics.

MATERIALS AND METHODS

"Glaucoma" was entered as a search term into Thomson Reuter's Web of Science database, and all articles related to the topic in the last decade were identified. The 50 highly cited articles (T50 list) were analyzed by topic, journal name, author name, year of the publication and Altmetric Attention Score (AAS). Descriptive statistics and Spearman correlation test were determined with the use of SPSS.

RESULTS

According to bibliometric criteria, there were 31,370 eligible articles and the median (range) citation number was recorded as 181.5 (158.75-250.75). The T50 list was ranked with AASs between 176 and 0. The median AAS was 5 (2.75-10). The main subjects of the top 10 highly cited articles were mostly related to follow-up and prognostics about glaucoma (n = 3), while the main subjects of the top 10 articles with the highest AAS were related to genetics in glaucoma pathogenesis (n = 2), treatment modalities (n = 2) and pathophysiology with therapeutics of glaucoma disease (n = 2). AASs and citation number showed a positive moderate correlation (r = 0.403 p = 0.004), although AASs did not correlate with journal impact factor (r = 0.36 p = 0.01). No statistically significant correlation was found for ASSs and citation numbers with H-index of the journals on the T50 list.

CONCLUSIONS

Bibliometric-based altmetric analyses offer important but different perspectives regarding article impact. This study provides valuable information about trending topics related to glaucoma research and its impact in both the academic literature and social media CLINICAL TRIAL REGISTRATION: With regard to the data characteristics of the manuscript, which is mainly retrospective and international, the clinical trial registration process is theoretically not applicable to this study.

Nuclear Receptors as Multiple Regulators of NLRP3 Inflammasome Function

Nuclear receptors are important bridges between lipid signaling molecules and transcription responses. Beside their role in several developmental and physiological processes, many of these receptors have been shown to regulate and determine the fate of immune cells, and the outcome of immune responses under physiological and pathological conditions. While NLRP3 inflammasome is assumed as key regulator for innate and adaptive immune responses, and has been associated with various pathological events, the precise impact of the nuclear receptors on the function of inflammasome is hardly investigated. A wide variety of factors and conditions have been identified as modulators of NLRP3 inflammasome activation, and at the same time, many of the nuclear receptors are known to regulate, and interact with these factors, including cellular metabolism and various signaling pathways. Nuclear receptors are in the focus of many researches, as these receptors are easy to manipulate by lipid soluble molecules. Importantly, nuclear receptors mediate regulatory mechanisms at multiple levels: not only at transcription level, but also in the cytosol via non-genomic effects. Their importance is also reflected by the numerous approved drugs that have been developed in the past decade to specifically target nuclear receptors subtypes. Researches aiming to delineate mechanisms that regulate NLRP3 inflammasome activation draw a wide range of attention due to their unquestionable importance in infectious and sterile inflammatory conditions. In this review, we provide an overview of current reports and knowledge about NLRP3 inflammasome regulation from the perspective of nuclear receptors, in order to bring new insight to the potentially therapeutic aspect in targeting NLRP3 inflammasome and NLRP3 inflammasome-associated diseases.

Dealing with rhegmatogenous retinal detachment in patients under 40 years old: a tertiary center results

PURPOSE

The risk of rhegmatogenous retinal detachment (RRD) increases with age, but some studies report a secondary peak in younger patients. Since visual recovery in RRD depends on surgical treatment and, considering the personal, social and economic burden of low vision in the working-age population, our purpose was to analyze the features and outcomes of RRD in young patients.

METHODS

Clinical data of patients under 40 years old submitted to surgery for first time RRD, consecutively selected between 2016 and 2019, was analyzed. Patients with less than 3 months follow-up were excluded.

RESULTS

Eighty-nine eyes from 89 patients were included. Mean age was 31.2 ± 7.8 years (minimum 10 years) and 56% were female gender. Most patients (63%) had high myopia. Pars plana vitrectomy (79%) alone, combined with scleral buckling (1%) or scleral buckling alone (20%) was performed. Primary anatomical success was 72%, and final anatomical success was 91%. Final visual acuity of 20/40 or better was achieved in 29% of cases, but 28% remained under 20/400. The presence of myopia (p = 0.022), localized RRD (p = 0.007) and attached macula at presentation (p < 0.001) was associated with a better final visual acuity.

CONCLUSION

Management of RRD in young patients must be thorough. In younger patients, anatomical outcomes may be worse than in older patients. Myopia may be recognized as a major risk factor for RRD in this age group, but also as a protective factor for retinal function after surgery.