Interleukin-6 absence triggers intestinal microbiota dysbiosis and mucosal immunity in mice.

Interleukin-6 (IL-6) in mucosal immune cells is involved in post-injury intestinal regeneration, inflammation responses, and gastric homeostasis. However, the interaction between IL-6 and the dynamic balance of gut microbiota (GM) remains unexplored. Intestinal pathology was assessed by hematoxylin and eosin and periodic acid-Schiff staining in wild-type (WT) and IL-6 gene knockout (KO) C57BL/6J mice. GM profiles were established via high-throughput sequencing of the fecal bacterial 16S rRNA gene. Intestinal α- and ß-defensins were measured by quantitative real-time PCR; further, flow cytometry was performed to analyze isolated intraepithelial lymphocytes (IELs). Compared with the WT, IL-6 KO did not obviously change gut structures, but significantly reduced GM diversity, resulting in reduced metabolic pathways with decreased gram-positive but elevated gram-negative bacteria. More taxa alterations included differences at the phyla (e.g., increased Verrucomicrobia and decreased Firmicutes) and genera (e.g., increased Akkermansia and decreased Lactobacillus) levels. Absence of IL-6 also significantly increased intestinal expression of defensins α3 and α4 (Defa3 and Defa4) and the percentage of natural TCRγδ+ IELs, providing a molecular basis for triggering mucosal immune response. Therefore, IL-6 loss remodels GM composition and alters IEL maintenance, identifying IL-6 as a crucial cytokine for GM dysbiosis and mucosal immunity.

LukS-PV inhibits hepatocellular carcinoma cells migration by downregulating HDAC6 expression.

BACKGROUND: Hepatocellular carcinoma (HCC) is a clinically common malignant tumor worldwide. LukS-PV is the S component of Panton-Valentine leukocidin secreted by Staphylococcus aureus, which has shown anti-cancer activity. Based on previous findings, this study investigated the effects of LukS-PV on HCC migration and the potential molecular mechanisms involving acetylation pathways. METHODS: After treating HCC cells with different concentrations of LukS-PV, we used scratch assays to determine the mobility of the cancer cells. Western blots were used to determine the expression levels of migration-related proteins. Quantitative proteomic sequencing was used to evaluate proteomic changes in target proteins. Immunoprecipitation and liquid chromatography coupled with tandem mass spectrometry analyses were used to validate the binding of related target proteins. RESULTS: LukS-PV inhibited HCC cell migration in a concentration-dependent manner. In addition, LukS-PV attenuated the expression of histone deacetylase (HDAC)6, which is highly expressed in HCC cells. Further studies showed that LukS-PV increased the acetylation level of α-tubulin by down-regulating HDAC6, which resulted in the inhibition of HCC cell migration. CONCLUSION: Taken together, our data revealed a vital role of LukS-PV in suppressing HCC cell migration by down-regulating HDAC6 and increasing the acetylation level of α-tubulin.

CD226 knockout alleviates high-fat diet induced obesity by suppressing proinflammatory macrophage phenotype.

Obesity is associated with chronic low-grade inflammation, contributing to an increasing prevalence of chronic metabolic diseases, such as insulin resistance, non-alcoholic fatty liver disease (NALFD), and steatohepatitis. Macrophages are the predominant immune cells in adipose tissues. Adipose tissue macrophages (ATMs) would switch to pro-inflammatory M1 state during obesity, causing local and systemic inflammation. However, the regulatory mechanism of ATMs has not yet been well described within this process. Using a high-fat diet (HFD)-induced mouse obesity model, we found that the costimulatory molecule CD226 was highly expressed on ATMs and knockout (KO) of CD226 alleviated obesity caused by HFD. Loss of CD226 reduced the accumulation of ATMs and hindered macrophage M1 polarization, with lower serum proinflammatory cytokine levels. Furthermore, deficiency of CD226 on ATMs decreased the phosphorylation levels of VAV1, AKT, and FOXO1 and thereby upregulated PPAR-γ. Further administration of PPAR-γ inhibitor restored M1 phenotype in CD226KO ATMs. In summary, loss of CD226 alleviates the HFD-induced obesity and systemic inflammation through inhibition of the accumulation and M1 polarization of ATMs in which PPAR-γ-dependent signaling pathway is involved, suggesting that CD226 may be identified as a potential molecular target for the clinical treatment of obesity.

Immunoassays Using Optical-Fiber Sensor with All-Directional Chemiluminescent Collection.

While chemiluminescent optical-fiber sensors present essential advantages for immunoassays of biomarkers, an inherent limitation hampering their detection sensitivity is the low collection efficiency of chemiluminescent emission induced by samples, owing to the microspatial scale of an optical fiber for transmission of light via total internal reflection. Here we present a robust approach to overcome this limitation, based on a uniquely designed all-optical chemiluminescent collection vial (CC vial) by using a concave mirror and a coaxial tubular mirror as its bottom and wall, respectively. Using cardiac troponin I (cTnI), a highly specific but low abundance cardiac biomarker, as the test sample, we show that accurate assays can be achieved in a wide linear range of 1-80000 pg/mL. The limit of detection is as low as 0.31 pg/mL, which is about 2 orders of magnitude lower than that obtained by a normal chemiluminescent optical fiber sensor. The method is successfully applied for determination of cTnI in real human serum samples with good accuracy and repeatability. Our study shows that the method can perform an all-directional collection of the chemiluminescent emission, thus, greatly enhancing the collection efficiency and improving the sensitivity of the immunoassays. It is also worth mentioning that the proposed strategy requires neither complex equipment nor additional chemicals, making it a cost-effective and universal approach for ultrasensitive detection of trace biomarkers.

A portable pencil-like immunosensor for point-of-care testing of inflammatory biomarkers.

Portable devices for immunoassays are in high demand for point-of-care testing (POCT) of biomarkers. Here, we report a robust portable pencil-like immunosensor (PPS) platform for the determination of three inflammatory biomarkers including interleukin-6 (IL-6), procalcitonin (PCT), and C-reactive protein (CRP) in human serum samples. The PPS platform is composed of a unique pencil-like optical-fiber-based sensor, a reagent strip consisting of a series of pencil-cap-like wells, and a battery-powered photon counting detector for recording chemiluminescence. The PPS probe moves from well to well with a plug-into/out approach and goes through the immunoassay steps. Each fiber probe in the PPS platform can be sequentially used in up to 10 assays by simply propelling the intact probe out of the pencil body. The PPS platform is well-integrated into a portable suitcase-like device (32 cm × 23 cm × 11 cm) and is only 3 kg in weight. The sensor has good repeatability and can maintain 90% response after 14 days of storage at room temperature, showing its ability for assays in the field. The good linear relationship and efficient dynamic range with a limit-of-detection (LOD) of 1.05 pg/mL for IL-6, 10.64 pg/mL for PCT, and 29.40 ng/mL for CRP are obtained. The assay results are compared with clinical methods, and the findings confirm the high accuracy and precision of the proposed method. The proposed PPS platform is versatile and operable with minimal instruments and technical skills and simplifies the process of immune analysis, thus has great prospects for POCT of biomarkers. Graphical abstract.

Chemiluminescent Optical Fiber Immunosensor Combining Surface Modification and Signal Amplification for Ultrasensitive Determination of Hepatitis B Antigen.

Optical fiber based immunosensors are very attractive for biomarker detection. In order to improve the sensor response, we propose a promising strategy which combines porous-layer modification of the fiber surface and streptavidin-biotin-peroxidase nano-complex signal amplification in chemiluminescent detection. Two hepatitis B antigens, hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg), are used as the targets for analysis using the proposed sensor. Comparing to immunoassays using normal optical fiber sensors, the response of the present sensor is enhanced by a factor of 4.8 and 6.7 for detection of HBsAg and HBeAg, respectively. The limit-of-quantitation of the proposed method is as low as 0.3 fg/mL (0.01 fg/mL) with a wide linear response range of 3 fg/mL-150 ng/mL (0.1 fg/mL-160 ng/mL) for sensing HBsAg (HBeAg). Quantitative determination of HBsAg and HBeAg in human serum samples is performed, showing the applicability of the proposed method for biomarker detection.

LukS-PV inhibits the proliferation of hepatocellular carcinoma cells by maintaining FOXO3 stability via the PI3K/AKT signaling pathway.

Hepatocellular carcinoma(HCC) is one of the common malignant tumors. LukS-PV is the S component of Panton-Valetine leukocidin(PVL) secreted by Staphylococcus aureus. Forkhead box O3 (FOXO3) is a member of the FOXO subfamily of transcription factors that acts as a tumor suppressor. In this study, we investigated the role of LukS-PV on the proliferation of HCC and explored possible mechanisms. We treated HCC cells with various concentrations of LukS-PV and evaluated the effect of LukS-PV on cell viability using the cell counting kit-8 and colony formation assays. Real-time PCR and western blot assays were used to analyze mRNA and protein expression levels, respectively. Immunofluorescence staining was performed to examine the intracellular localization of FOXO3. The expression of FOXO3 and its downstream target genes were analyzed by immunohistochemical staining. The protein synthesis inhibitor cycloheximide and the proteosome inhibitor MG132 were used to explore the potential mechanisms by which LukS-PV regulated FOXO3. We demonstrated that LukS-PV inhibited the proliferation of HCC cells in a concentration dependent manner. LukS-PV upregulated FOXO3 expression both in vitro and in vivo. Moreover, LukS-PV facilitated the entry of FOXO3 into the nucleus and, subsequently, regulated the transcription of downstream target genes. In addition, we discovered that LukS-PV decreased the expression of phosphorylated FOXO3 through the PI3K/AKT signaling pathway and maintained FOXO3 protein stability via the ubiquitin-proteasome pathway. Taken together, our data indicated that LukS-PV exert anticancer activities through FOXO3. LukS-PV may be a promising candidate for HCC treatment.

Loss of CD226 protects apolipoprotein E-deficient mice from diet-induced atherosclerosis.

CD226 is a costimulatory molecule that regulates immune cell functions in T cells, natural killer cells, and macrophages. Because macrophage-derived foam cell formation is a crucial factor contributing to the development of atherosclerosis, we aimed to evaluate the potential roles of CD226 in the pathogenesis of atherosclerosis. The effects of CD226 on atherosclerosis were investigated in CD226 and apolipoprotein E double-knockout (CD226-/- ApoE-/-) mice fed with a high-cholesterol atherogenic diet. CD226 expression in macrophages was evaluated using flow cytometry. Histopathological analysis was performed to evaluate the atherosclerotic lesions. Inflammatory cell infiltration was detected using immunofluorescence staining. Bone marrow-derived macrophages (BMDMs) and peritoneal macrophages (PEMs) were isolated from the mice and used to explore the mechanism in vitro. The in vivo results indicated that CD226 knockdown protected against atherosclerosis in ApoE-/- mice, evidenced by reduced plaque accumulation in the brachiocephalic artery, aortic roots, and main aortic tree. CD226 gene-deficient macrophages showed reduced foam cell formation under ox-low density lipoprotein stimulation compared with wild-type (WT) cells. CD226 deficiency also decreased the expression of CD36 and scavenger receptor (SR)-A (responsible for lipoprotein uptake) but increased the expression of ATP-binding cassette transporter A1 and G1 (two transporters for cholesterol efflux). Therefore, loss of CD226 hinders foam cell formation and atherosclerosis progression, suggesting that CD226 is a promising new therapeutic target for atherosclerosis.

Acute Cold Water-Immersion Restraint Stress Induces Intestinal Injury and Reduces the Diversity of Gut Microbiota in Mice.

Growing evidence has demonstrated that stress triggers gastrointestinal (GI) disorders. This study aimed to investigate how the acute cold water-immersion restraint (CWIR) stress affects intestinal injury and gut microbiota (GM) distribution. Male C57BL/6 mice were used to establish a CWIR animal model. Hematoxylin-eosin and periodic acid-Schiff staining were performed to assess intestinal histopathological changes. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis and immunofluorescence staining were used to evaluate the expression of inflammatory cytokines and immune cell infiltration in the intestinal tissues. The gut permeability and intestinal occludin protein expression were determined through fluorescein isothiocyanate-dextran detection and western blot, respectively. GM profiles were analyzed via high-throughput sequencing of the fecal bacterial 16S rRNA genes. Results showed that CWIR induced more severe intestinal mucosal injury compared to the control, leading to a significant increase in tumor necrosis factor-α expression, but no infiltration of neutrophil and T cells. CWIR also resulted in GI disruption and increased the permeability of the intestinal mucosa. GM profiles showed that CWIR reduced GM diversity of mice compared with the control group. Specifically, aerobic and gram-negative bacteria significantly increased after CWIR, which was associated with the severity of gut injury under stress. Therefore, acute CWIR leads to severe intestinal damage with inflammation and disrupts the GM homeostasis, contributing to decreased GM diversity. Our findings provide the theoretical basis for the further treatment of intestinal disorders induced by CWIR.

[Preparation and identification of mouse-derived monoclonal antibodies to human ST2 molecule].

Objective To prepare mouse-derived monoclonal antibody against human suppression of tumorigenicity 2 (ST2) molecule and make initial identification. Methods BALB/c mice were immunized with the recombinant human ST2 molecule, and the conventional B-cell hybridoma technology was used to prepare the anti-ST2 monoclonal antibodies (mAbs). Their application in western blotting, immunohistochemistry, and flow cytometry were evaluated. The sandwich ELISA detecting soluble ST2 was established to test the serum levels of ST2 in patients with heat stroke. And the ST2 luciferase reporter gene detection system was established to detect their neutralization activity. Results Thirty-eight hybridoma cell lines secreting mouse anti-human ST2 mAb were obtained and named from XA325.1 to XA325.38. Preliminary screening and identification of them showed that they can be used to identify the purified recombinant ST2 proteins and cellular expressed ST2 using western blotting and immunohistochemistry. Two of them can be used for flow cytometry to identify the exogenously transfected ST2 molecule on the cell surface. Using XA325.16 mAb coating, combined with XA325.5-labeled biotin, an ELISA kit detecting soluble ST2 in serum was established. It was found that the serum levels of ST2 in patients with heat stroke increased significantly. Moreover, XA325.5 was found with neutralizing activity which can block the biological effect of IL-33. Conclusion A set of mouse anti-human ST2 mAbs was prepared, which can be used in a variety of immunological detection techniques. Besides, XA325.5 neutralizing antibody has a potential value in clinical application.

Silencing of HuR Inhibits Osteosarcoma Cell Epithelial-Mesenchymal Transition via AGO2 in Association With Long Non-Coding RNA XIST.

BACKGROUND: Osteosarcoma (OS) is a highly malignant and aggressive bone tumor. This study was performed to explore the mechanisms of HuR (human antigen R) in the progression of OS. METHODS: HuR expression levels in OS tissues and cells were detected by immunohistochemistry and western blotting. HuR siRNA was transfected into SJSA-1 OS cells to downregulate HuR expression, and then cell proliferation, migration, and epithelial-mesenchymal transition (EMT) were evaluated. RNA immunoprecipitation was performed to determine the association of the long non-coding RNA (lncRNA) XIST and argonaute RISC catalytic component (AGO) 2 with HuR. Fluorescence in situ hybridization analysis was performed to detect the expression of lncRNA XIST. Western blotting and immunofluorescence assays were performed to observe AGO2 expression after HuR or/and lncRNA XIST knockdown. RESULTS: Knockdown of HuR repressed OS cell migration and EMT. AGO2 was identified as a target of HuR and silencing of HuR decreased AGO2 expression. The lncRNA XIST was associated with HuR-mediated AGO2 suppression. Moreover, knockdown of AGO2 significantly inhibited cell proliferation, migration, and EMT in OS. CONCLUSION: Our findings indicate that HuR knockdown suppresses OS cell EMT by regulating lncRNA XIST/AGO2 signaling.

CD226 Is Required to Maintain Megakaryocytes/Platelets Homeostasis in the Treatment of Knee Osteoarthritis With Platelet-Rich Plasma in Mice.

Platelet-rich plasma (PRP) is a platelet-based application used to treat osteoarthritis (OA) clinically. The co-stimulatory molecule CD226 is expressed in T cells, NK cells, and also platelets. However, exact effects of CD226 on platelets and whether its expression level influences PRP efficacy are largely unknown. Here, CD226fl/flPF4-Cre mice were obtained from mating CD226 fl/fl mice with PF4-Cre mice. Blood samples and washed platelets were collected from the mice eyeballs to undergo routine blood tests and transmission electron microscopy. Differentially expressed proteins were detected by iTRAQ-based proteomics analysis. Animal OA models were established through surgical destabilization of the medial meniscus (DMM) for C57BL/6 wildtype mice, followed by PRP injection to evaluate the effects of platelet CD226 on PRP efficacy. The results showed that deletion of platelet CD226 increased the number of megakaryocytes (MKs) in bone marrow (BM) but reduced MKs in spleen, combined with significantly decreased platelet amounts, α-granule secretion, and reduced immature platelets; indicating that absence of platelet CD226 may disrupt MK/platelet homeostasis and arrested platelet release from MKs. Sequencing analysis showed abnormal ribosomal functions and much downregulated proteins in the absence of platelet CD226. Autophagy-related proteins were also reduced in the CD226-absent MKs/platelets. Moreover, deletion of platelet CD226 diminished the protective effects of PRP on DMM-induced cartilage lesions in mice, and PDGF restored it. Therefore, deficiency of platelet CD226 inhibited platelet maturation, secretion, and normal ribosomal functions, which may lead to depressed PRP efficacy on OA, suggesting that CD226 is required to regulate platelet growth, functions, and its application.

The Effect of Cognitive Behavioral Therapy on Depression, Anxiety, and Stress in Patients With COVID-19: A Randomized Controlled Trial.

Background: As a public health emergency of international concern, the COVID-19 outbreak has had a tremendous impact on patients' psychological health. However, studies on psychological interventions in patients with COVID-19 are relatively rare. Objectives: This study examined the effectiveness of Cognitive Behavioral Therapy (CBT) in relieving patients' psychological distress during the COVID-19 epidemic. Methods: Ninety-three eligible participants selected by cluster sampling were randomized to an intervention group (N = 47) and a control group (N = 46). Participants in the control group received routine treatment according to the Chinese Management Guidelines for COVID-19, while participants in the intervention group received routine treatment with additional CBT. The Chinese Version of Depression Anxiety and Stress Scale-21 (DASS-21) was used to evaluate depression, anxiety, and stress for all participants at baseline and post-intervention. Two-sided t-test, and proportion tests were used to examine the differences between the intervention and control group for each DASS-21 indicator. Univariate linear regression was used to examine the association between chronic disease status and change in each DASS-21 indicator after intervention. Two-way scatter plots were generated to show the association of the length of hospital stay and the changes of each DASS-21 indicator by intervention and control groups. Results: Significant decreases in means were found for scales of depression, anxiety, stress and total DASS-21 in both intervention (p < 0.001) and control group (p = 0.001), with participants in the intervention group having a bigger reduction in means. After the intervention, more participants in the intervention group had no depression or anxiety symptoms than in the control group, but no statistical differences were found (p > 0.05). Compared with participants with chronic disease, participants with no chronic disease had a significantly larger reduction of total DASS-21 scale (coefficient = -4.74, 95% CI: -9.31; -0.17).The length of hospital stay was significantly associated with a greater increase in anxiety scale in the intervention group (p = 0.005), whilst no significant association was found in the control group (p = 0.29). Conclusions: The patients with COVID-19 experienced high levels of anxiety, depression and stress. Our study result highlights the effectiveness of CBT in improving the psychological health among patients with COVID-19, also suggests that CBT should be focused on patients with chronic disease and those who have longer hospital stays. These results have important implications in clinical practice in improving psychological health in the context of COVID-19 pandemic. Trial Registration: ISRCTN68675756. Available at: http://www.isrctn.com/ISRCTN68675756.

Optical Fiber-Mediated Immunosensor with a Tunable Detection Range for Multiplexed Analysis of Veterinary Drug Residues.

We describe herein a newly developed chemiluminescent optical fiber immunosensor (OFIS) with a tunable detection range for multiplexed analysis of veterinary drug residues with vastly different concentrations in milk samples. The optical fiber probe is used as a carrier of biorecognition element as well as a transducer, enabling a low-cost compact design, which makes this system suitable for cost-effective on-site detection of the target analytes. Importantly, the synergy between modulation of the length of the optical fiber sensing region and the number of fibers allows performing multiplexed immunoassays in an easily controllable manner over a tunable detection range from pg/mL to µg/mL analyte concentrations. By combining the optical fiber sensor with a nanocomplex signal amplification system, a highly sensitive chemiluminescent OFIS system is demonstrated for the multiplexed assaying of veterinary drug residues in milk samples with linear ranges of 10-(2 × 104) pg/mL for chloramphenicol, 0.5-500 ng/mL for sulfadiazine, and 0.1-300 µg/mL for neomycin. This controllable strategy, based on modulation of the fiber probe, provides a versatile platform for multiplexed quantitative detection of both low-abundance and high-abundance targets, which shows great potential for on-site testing in food safety.

Ultra-sensitive capillary immunosensor combining porous-layer surface modification and biotin-streptavidin nano-complex signal amplification: Application for sensing of procalcitonin in serum.

We propose a promising capillary immunosensor by combining porous-layer surface modification of an open-tubular capillary and streptavidin-biotin-peroxidase nano-complex signal amplification of chemiluminescence read-out. The immunosensor, namely Porous Layer Open Tubular-Signal Amplification (PLOT-SA) sensor, is successfully applied for ultra-sensitive sensing of procalcitonin (PCT) in human serum samples. The results show the PLOT-SA sensor exhibits essential features for PCT determination, including a wide linear detection range of 0.1 pg/mL-100 ng/mL, an extremely low limit-of-quantitation of 0.01 pg/mL, excellent intra-day and inter-day stability and reproducibility with RSDs less than 4.5%. Our study provides a reliable and robust approach for developing capillary sensors that can be used in analysis of complex biologic samples.

Analysis on Fungal Diversity in Rhizosphere Soil of Continuous Cropping Potato Subjected to Different Furrow-Ridge Mulching Managements.

Knowledge about fungi diversity following different planting patterns could improve our understanding of soil processes and thus help us to develop sustainable management strategies. The objective of this study was to determine the impact of different furrow-ridge mulching techniques on fungal diversity in rhizosphere soil under continuous cropping system. The investigated treatments were: flat plot without mulch (CK); flat plot with mulch (T1); on-ridge planting with full mulch (T2); on-furrow planting with full mulch (T3); on-ridge planting with half mulch (T4); and on-furrow planting with half mulch (T5). NGS (Illumina) methods and ITS1 sequences were used in monitoring fungi diversity of the potato rhizosphere soil. The fungi diversity in the rhizosphere soil was ranked in the order T5 > T2 > T4 > T1 > CK at the early growth stage and T2 > T3 > T1 > T4 > CK at the late growth stage of potato. The fungal communities found in the rhizosphere soil were Ascomycota, Zygomycota, Basidiomycota, Chytridiomycota, and other unidentified fungal communities. Among the fungal community in the rhizosphere soil, Ascomycota was found to be dominant fungi population, with the highest percentage (89%) in the T5 soil whereas the T2 soils had the lowest percentage (67%). The Fusarium abundance in fully-mulched treated soils was higher than in half-mulched treated soil. The dominant genus in the T4 soil was Mortierella, whereas lower populations (1-2%) of Scutellinia, Cryphonectria, Acremonium, and Alternaria were found in that treatment. Among the eumycetes, the dominant fungal class in all treated soils was the Sordariomycetes, which ranged from 57 to 85% in T2 and T5 soils, respectively. The Fusarium percentages in half-mulched treated soils (T4 and T5) were 55 and 28% lower than that of complete mulched treated soils (T2 and T3), respectively. The cluster analysis results showed that, CK, T4, and T5 treated soils and T1, T2, and T3 treated soils had similarities in microbial compositions, respectively. Potato tuber yield was greater under the on-ridge planting with full mulch (T2) treated soil, followed by on-ridge planting with half-mulch (T4) treated soil. The rhizosphere soil under the on-ridge planting with full-mulch (T2) soil had the highest fungal diversity, suggesting that this management was the best environment for fungi, whereas the on-ridge planting with half-mulch (T4) soil had the minimum abundance of Fusarium.