Novel lipopeptides of ESAT-6 induce strong protective immunity against Mycobacterium tuberculosis: Routes of immunization and TLR agonists critically impact vaccine’s efficacy

Mycobacterium tuberculosis (Mtb), the bacterial cause of tuberculosis, is a leading infectious agent worldwide. The development of a new vaccine against Mtb is essential to control global spread of tuberculosis, since the current vaccine BCG is not very effective and antibiotic resistance is a serious, burgeoning problem. ESAT-6 is a secreted protein of Mtb, which is absent in BCG but has been implicated in inducing protective immunity against Mtb. Peptide based subunit vaccines are attractive due to their safety and high specificity in eliciting immune responses, but small synthetic peptides are usually not very immunogenic. We have designed a novel subunit vaccine for Mtb by using simple lipid (palmitic acid) modified derivatives of peptides from ESAT-6 protein corresponding to dominant human T cell epitopes and examined their ability to stimulate protective immunity against Mtb by intranasal and subcutaneous immunization in mice. We also investigated how individual TLR agonists as adjuvants (PolyI:C, MPL and GDQ) contribute to enhancing the induced immune responses and resulting protective efficacy of our vaccine. We observed that single C-terminal palmitoyl-lysine modified lipopeptides derived from ESAT-6 induce significant cellular immune responses on their own upon mucosal and subcutaneous immunizations. Intriguingly, a combination of immunogenic lipopeptides of ESAT-6 antigen exhibited local (pulmonary) and systemic immune responses along with efficient protective efficacy when administered intranasally or subcutaneously. Surprisingly, combination of ESAT-6 derived lipopeptides with a TLR-4 agonist (MPL) enhanced protection, whereas TLR-3 (Poly I:C) and TLR-7/8 agonists (gardiquimod, GDQ) led to reduced protection associated with specific local and systemic immune modulation. Our studies demonstrate the potential of ESAT-6 derived lipopeptides as a promising vaccine candidate against Mtb, and emphasize that selection of adjuvant is critical for the success of vaccines. These findings demonstrate the promise of synthetic lipopeptides as the basis of a subunit vaccine for TB.     

灯盏乙素介入IP3R-Ca2+途径抑制β淀粉样蛋白诱导的神经细胞凋亡

目的：观察灯盏乙素（Scu）对β淀粉样蛋白（Aβ）诱导的细胞模型中1，4，5-三磷酸肌醇受体（IP₃R）-Ca²⁺途径的影响，探讨其在阿尔茨海默病（AD）病程中可能发挥的积极作用。方法：选用神经母细胞瘤细胞分为对照组、Scu处理组、Aβ处理组、Aβ+Scu （高、中、低）处理组及Aβ+IP₃R拮抗剂组，用CCK-8法筛选药物浓度并检测各组细胞生存率；用酶联免疫吸附法检测各组细胞中1，4，5-三磷酸肌醇（IP₃）的含量；用蛋白印迹和实时荧光定量聚合酶链反应方法检测各组细胞IP₃R和凋亡相关因子Caspase-3、Bcl-2、Bax的蛋白及mRNA的表达水平；用激光共聚焦显微镜观察各组细胞内Ca²⁺浓度的变化；用AnnexinV/PI双染法测定各组细胞的凋亡率。结果：与对照组和Scu处理组相比，Aβ处理组细胞存活率下降，IP₃含量升高，IP₃R、Bax和Caspase-3的蛋白及mRNA表达上调，Bcl-2蛋白及mRNA的表达下调，细胞胞浆内Ca²⁺浓度及细胞凋亡率升高；Aβ+Scu处理组细胞中各检测指标的变化与Aβ处理组的结果正好相反，IP₃R通道下游指标的变化与Aβ+IP₃R拮抗剂组基本一致。结论：Scu能够下调通路蛋白IP₃、IP₃R的表达，抑制Aβ介导的Ca²⁺内流所致的细胞凋亡，可能通过对IP₃R-Ca²⁺途径的调控来影响AD病程。     

Investigation of non-linear Mate1-mediated efflux of trimethoprim in the mouse kidney as the mechanism underlying drug-drug interactions between trimethoprim and organic cations in the kidney

The purpose of this study was to elucidate the involvement of Mate1 in the tubular secretion of trimethoprim and saturation of Mate1-mediated efflux to address the mechanisms underlying the pharmacokinetic drug interactions with trimethoprim. Trimethoprim is a more potent inhibitor of MATE2-K than MATE1 with K_i values (μM) of 0.030–0.28 and 2.4–5.9, respectively. Trimethoprim is a substrate of human MATE1 and MATE2-K with K_m values of 2.3 ± 0.9 and 0.018 ± 0.004 μM, and mouse Mate1, but not human OCT2, mouse Oct1 and Oct2. Pyrimethamine significantly reduced the renal clearance (CL_R) of trimethoprim (mL/min/kg) from 40.0 ± 5.1 to 20.1 ± 3.7 (p < 0.05). Trimethoprim was given to mice at three infusion rates (150, 500, and 1500 nmol/min/kg). Together with an increase in the plasma concentrations of trimethoprim, the CL_R (mL/min/kg) of trimethoprim decreased to 25.9 ± 3.2, 13.5 ± 5.7, and 8.92 ± 1.50 at the respective rates. Trimethoprim decreased the CL_R of rhodamine 123 in an infusion rate-dependent manner: 11.5 ± 1.3 (control), 5.17 ± 1.55, 1.31 ± 0.50, and 0.532 ± 0.180. These results suggest that Mate1 mediates the tubular secretion of trimethoprim, and at therapeutic doses, MATEs-mediated efflux can be saturated, and thereby, cause drug interactions with other MATE substrates.     

Visfatin as a therapeutic target for rheumatoid arthritis

Introduction: The rising prevalence of musculoskeletal pathologies in developed countries has caused a dramatic impact on social welfare. Amidst these musculoskeletal pathologies is Rheumatoid arthritis (RA), a chronic systemic autoimmune disease that mostly affects the synovium. RA metabolic-associated alterations, including distorted adipokine production, enhance RA inflammatory environment. Among the altered adipokines, visfatin is particularly involved in RA inflammation and catabolism and stands out as an essential enzyme linked to critical cell features.

Areas covered: We discuss the potential mechanism supporting the contribution of visfatin to RA and the association between RA and obesity. We discuss the repurposing of cancer-tested drugs to inhibit visfatin in the context of RA. Additionally, we address the possibility of combining these drugs with current RA therapy. Finally, we explore the future of visfatin as an RA biomarker or therapeutic target.

Expert opinion: Inhibition of visfatin has become an interesting therapeutic approach for RA pathology. Such a feat has already been attained in oncology using small molecule inhibitors, which suggest that a similar course of action would be worth pursuing in the RA context. Visfatin will become an important biomarker and therapeutic target for RA.     

The relationships among monocyte subsets,miRNAs and inflammatory cytokines in patients with acute myocardial infarction

Background

Acute myocardial infarction (AMI) causes irreversible myocardial damage and release of inflammatory mediators, including cytokines, chemokines and miRNAs. We aimed to investigate changes in the levels of cytokines (IL-6, TNF-α and IL-10), miRNAs profiles (miR-146 and miR-155) and distribution of different monocyte subsets (CD14++CD16-, CD14++CD16+, CD14+CD16++) in the acute and post-healing phases of AMI.

Spread of an Enterococcus faecalis sequence type 6 (CC2) clone in patients undergoing selective decontamination of the digestive tract

Enterococcus faecalis (E. faecalis) is a common cause of nosocomial infection in immunocompromised patients. The presence and dissemination of high‐risk clonal complexes, such as CC2, is an ongoing problem in hospitals. The aim of this work was to characterize 24 E. faecalis isolates from ICU patients undergoing selective decontamination of the digestive tract (SDD) by phenotypical (antimicrobial susceptibility) and genotypical (presence of virulence genes, RAPD‐PCR and MLST) methods. Our results showed high prevalence of the ST6 E. faecalis clone (91.6%), especially adapted to the hospital environment, with a multidrug resistance pattern and a multitude of putative virulence genes. In addition, ST179 (4.2%) and ST191 (4.2%) were detected. By RAPD–PCR analysis, the 22 isolates identified as ST6 showed six different DNA patterns, while the two remaining isolates, ST179 and ST191, showed two additional profiles. CC2 is a known clonal complex with high adaptability to hospital environment and worldwide distribution. The high prevalence of the ST6 clone in the studied population could be related to the presence of gentamicin in the SDD mixture since most strains were gentamicin resistant. Consequently, strict surveillance should be applied for rapid detection and control of this clone to prevent future spread outside the ICU.     

丹蛭降糖胶囊通过mTOR/S6K1信号通路对糖尿病肾病大鼠的干预作用研究

目的研究丹蛭降糖胶囊对糖尿病肾病大鼠的肾脏病理改变和足细胞自噬水平的影响,初步探讨其相应的作用机制。方法选取GK大鼠40只,采用醋酸脱氧皮质酮-盐皮下注射联合高脂饲料喂养诱导糖尿病肾病模型。造模成功后随机分为模型组、丹蛭降糖胶囊低剂量组[0.54 g/(kg·d)]、高剂量组[1.08 g/(kg·d)]、缬沙坦组[10 mg/(kg·d)],每组10只。另选取10只同周龄正常Wistar大鼠作为正常组。模型组和正常组给予等容积生理盐水。连续灌胃10周后检测空腹血糖(FBG)、血肌酐(SCr)、尿素氮(BUN)和尿微量蛋白(U-mAlb)。Western Blot检测肾小球p-mTOR、p-S6K1、Beclin-1、LC3和Nephrin蛋白的表达,HE染色和PAS染色后于光镜下观察肾脏病理变化,电镜下观察各组亚细胞形态结构变化。结果与正常组比较,模型组FBG、SCr、BUN、U-mAlb水平升高(P<0.01);与模型组比较,丹蛭降糖胶囊低、高剂量组和缬沙坦组U-mAlb水平降低(P<0.01)。模型组可见肾小球基底膜增厚,系膜基质沉积,足细胞损伤,各用药组均有不同程度改善,丹蛭降糖胶囊高剂量组足细胞内有较多自噬体形成。与正常组比较,模型组p-mTOR、p-S6K1的表达增高,Nephrin、Beclin-1和LC3的表达水平降低(P<0.01);与模型组比较,各用药组p-mTOR、p-S6K1的表达下降,Nephrin、Beclin-1和LC3的表达增高(P<0.01)。丹蛭降糖胶囊高剂量组和缬沙坦组Beclin1、LC3Ⅱ/LC3Ⅰ水平较丹蛭降糖胶囊低剂量组升高(P<0.05)。结论丹蛭降糖胶囊具有减轻糖尿病肾病大鼠U-mAIb、足细胞损伤及相关肾脏病理改变的作用,其机制可能与抑制mTOR/S6K1信号通路进而提高足细胞的自噬活性有关。     

Serum retinol-binding protein 4 is associated with insulin resistance in patients with early and untreated rheumatoid arthritis

ObjectiveRetinol-binding protein 4 (RBP4), systemic inflammation and insulin resistance (IR) are linked, yet the determinants of RBP4 and its impact on IR in rheumatoid arthritis (RA) are incompletely understood. The aim of this study was to explore the prevalence of IR in RA and investigate whether the serum levels of RBP4 were associated with IR in patients with RA.MethodsIn this study, 403 individuals with newly diagnosed and untreated RA were consecutively recruited. We calculated the Disease Activity Score assessed using 28-joint counts for swelling and tenderness (DAS28). Levels of serum RBP4, interleukin-6 (IL-6) and tumor necrosis factor (TNF) α were tested. IR was defined as Homeostasis model assessment for insulin resistance (HOMA-IR) index greater than or equal 2.40.ResultsIn those 403 patients, 68 (16.9%) were male and the median age was 43 years (IQR: 36–52). There was an evidently positive correlation between increased serum levels of RBP4 and increasing severity of RA (DAS28) (r = 0.403, P < 0.001). Furthermore, a modest positive correlation between levels of serum RBP4 and HOMA-IR score (r = 0.251; P < 0.0001) was found. Eighty-five patients (21.1%) in patients with RA were defined as IR (HOMA-IR ≥ 2.40), which was significantly higher than in normal cases (4.7%). In the patients with IR, serum levels of RBP4 were higher when compared with those in patients free-IR P < 0.001. The IR distribution across the quartiles of RBP4 ranged between 5.0% (first quartile) to 39.0% (fourth quartile), P for trend < 0.001. For each 1unit increase of RBP4, the unadjusted and adjusted risk of IR increased by 8% (OR: 1.08; 95% CI: 1.05–1.11, P < 0.001) and 5% (1.05; 1.02–1.09, P = 0.001), respectively. When RBP4 was added to the model containing established significant risk factors, AUROC (standard error) was increased from 0.768 (0.025) to 0.807(0.021). A significant difference in the AUC between the established risk factors alone and the addition of RBP4 was observed (difference, 0.039[0.004]; P = 0.02).ConclusionElevated serum levels of RBP4 were associated with increased risk of IR and might be useful in identifying RA at risk for IR and/or impaired glucose tolerance for early prevention strategies, especially in obese and women patients