BATF and BATF3 deficiency alters CD8+ effector/exhausted T cells balance in skin transplantation.

BACKGROUND: It is well-established that CD8+ T-cells play a critical role in graft rejection. The basic leucine zipper ATF-like transcription factor (BATF) and BATF3 are transcriptional factors expressed in T lymphocytes. Herein, we investigated the functions of BATF and BATF3 in the differentiation and exhaustion of CD8+ T cells following alloantigen activation. METHODS: Wild-type CD8+ T cells, BATF-deficient (Batf-/-) CD8+ T cells, and CD8+ T cells deficient in both BATF and BATF3 (Batf-/-Batf3-/-) were transferred to B6.Rag1-/- mice, which received skin allografts from BALB/c mice. Flow cytometry was conducted to investigate the number of CD8+ T cells and the percentage of effector subsets. RESULTS: BATF expression positively correlated with effector CD8+ T cell differentiation. BATF and BATF3 deficiency promoted skin allograft long-term survival and attenuated the CD8+ T cell allo-response and cytokine secretion. Finally, BATF and BATF3 deficiency prompted the generation of exhausted CD8+ T cells. CONCLUSIONS: Overall, our findings provide preliminary evidence that both BATF and BATF3 deficiency influences the differentiation of effector CD8+ T cells and mediates the exhaustion of CD8+ T cells, prolonging transplant survival. Targeting BATF and BATF3 to inhibit CD8+ T cell function has huge prospects for application as a therapeutic approach to prevent transplant rejection.

Cost-effective fabrication of a high-conductivity copper electrode for heterojunction solar cells via laser-induced selective metallization.

Replacing expensive silver with inexpensive copper for the metallization of silicon wafer solar cells can lead to significant reductions in material costs associated with cell production, but the susceptibility of the Cu material to oxidation remains a challenging issue to solve. In this study, we investigate copper metallization of Indium Tin Oxide surfaces to define copper grid electrodes for heterojunction cells. We propose a novel laser-induced selective metallization (LISM) method to fabricate large-scale copper electrodes for heterojunction solar cells at low cost. This study includes a comprehensive evaluation of the morphological characteristics and electrical properties of the electrodes. The effects of laser parameters on the morphology, composition, size, and conductivity of copper electrodes are investigated. The goal of establishing the process window is to obtain the optimal laser parameters for manufacturing highly conductive copper electrodes. These optimized parameters will then be employed to fabricate high-performance electrodes for solar cells. Furthermore, a detailed analysis of the mechanism underlying laser selective metallization is provided. The resulting Cu electrodes exhibit high conductivity and low resistivity of 1.98 × 10-5Ω.cm, demonstrating the potential of this method for efficient and cost-effective solar electrode production.

Inhibiting NFAT5 With KRN2 Mitigates Acute Allograft Rejection in a Murine Heart Transplantation Model.

ABSTRACT: Despite advancements in immunosuppressive therapy, acute allograft rejection remains an important challenge for heart transplantation patients. Nuclear factor of activated T-cells 5 (NFAT5), a member of the family of Rel homology domain-containing factors that plays an important role in regulating immune responses of T lymphocytes, may be closely associated with cardiac rejection. KRN2, as a specific inhibitor of NFAT5, is injected intraperitoneally daily starting from day 0 after murine heart transplantation. When compared with saline treatment, KRN2 treatment can improve allograft survival. Histologic examination revealed that the KRN2 treatment group experienced less-severe rejection, and enzyme-linked immunosorbent assay revealed lower levels of inflammatory cytokines in circulating serum. The proportion and number of T-cell subpopulations in the spleens were analyzed by flow cytometry. We found that KRN2 treatment reduced the proportions of CD4 + IFN-γ + , CD4 + IL-17A + , and CD4 + IL-4 + Th cells, whereas increasing CD4 + Foxp3 + Treg cells compared with the control group. These findings suggest that KRN2 attenuates acute allograft rejection by regulating CD4 + T lymphocyte responses. NFAT5 could be a promising therapeutic target for preventing acute allograft rejection.

[Structure Design of Hip Joint Parallel Rehabilitation Exoskeleton].

At present, most of the research on hip exoskeleton robots adopts the method of decoupling analysis of hip joint motion, decoupling the ball pair motion of hip joint into rotational motion on sagittal plane, coronal plane and cross section, and designing it into series mechanism. Aiming at the problems of error accumulation and man-machine coupling in series mechanism, a parallel hip rehabilitation exoskeleton structure is proposed based on the bionic analysis of human hip joint. The structure model is established and the kinematics analysis is carried out. Through the OpenSim software, the curve of hip flexion and extension, adduction and abduction angle in a gait cycle is obtained. The inverse solution of the structure is obtained by the D-H coordinate system method. The gait data points are selected and compared with the inverse solution obtained by ADAMS software simulation. The results show that the inverse solution expression is correct. The parallel hip exoskeleton structure can meet the requirements of the rotation angle of the hip joint of the human body, and can basically achieve the movement of the hip joint, which is helpful to improve the human-computer interaction performance of the exoskeleton.

Robust metallic micropatterns fabricated on quartz glass surfaces by femtosecond laser-induced selective metallization.

Quartz glass has a wide range of application and commercial value due to its high light transmittance and stable chemical and physical properties. However, due to the difference in the characteristics of the material itself, the adhesion between the metal micropattern and the glass material is limited. This is one of the main things that affect the application of glass surface metallization in the industry. In this paper, micropatterns on the surface of quartz glass are fabricated by a femtosecond laser-induced backside dry etching (fs-LIBDE) method to generate the layered composite structure and the simultaneous seed layer in a single-step. This is achieved by using fs-LIBDE technology with metal base materials (Stainless steel, Al, Cu, Zr-based amorphous alloys, and W) with different ablation thresholds, where atomically dispersed high threshold non-precious metals ions are gathered across the microgrooves. On account of the strong anchor effect caused by the layered composite structures and the solid catalytic effect that is down to the seed layer, copper micropatterns with high bonding strength and high quality, can be directly prepared in these areas through a chemical plating process. After 20-min of sonication in water, no peeling is observed under repeated 3M scotch tape tests and the surface was polished with sandpapers. The prepared copper micropatterns are 18 µm wide and have a resistivity of 1.96 µΩ·cm (1.67 µΩ·cm for pure copper). These copper micropatterns with low resistivity has been proven to be used for the glass heating device and the transparent atomizing device, which could be potential options for various microsystems.

DNA walker-amplified signal-on electrochemical aptasensors for prostate-specific antigen coupling with two hairpin DNA probe-based hybridization reaction.

Electrochemical aptasensing systems have been developed for screening low-abundance disease-related proteins, but most of them involve multiple washings and multi-step separation during measurements, and thus are disadvantageous for routine use. In this work, an innovative and simple electrochemical aptasensing platform was designed for the voltammetric detection of prostate-specific antigen (PSA) in biological fluids without any washing and separation steps. This system mainly included a PSA-specific aptamer, a DNA walker and two hairpin DNA probes (i.e., thiolated hairpin DNA1 and ferrocene-labeled hairpin DNA2). Introduction of target PSA caused the release of the DNA walker from a partially complementary aptamer/DNA walker hybridization strand. The dissociated DNA walker opened the immobilized hairpin DNA1 on the electrode, accompanying subsequent displacement reaction with hairpin DNA2, thus resulting in the DNA walker step-by-step reaction with numerous hairpin DNA1 probes on the sensing interface. In this case, numerous ferrocene molecules were close to the electrode to amplify the voltammetric signal within the applied potentials. All reactions and electrochemical measurements including the target/aptamer reaction and hybridization chain reaction were implemented in the same detection cell. Under optimal conditions, the fabricated electrochemical aptasensor gave good voltammetric responses relative to the PSA concentrations within the range of 0.001-10 ng mL-1 at an ultralow detection limit of 0.67 pg mL-1. A good reproducibility with batch-to-batch errors was acquired for target PSA down to 11.5%. Non-target analytes did not interfere with the voltammetric signals of the electrochemical aptasensors. Meanwhile, 15 human serum specimens were measured with electrochemical aptasensors, and displayed well-matched results in comparison with the referenced human PSA enzyme-linked immunosorbant assay (ELISA) method. Significantly, this method provides a new horizon for the quantitative monitoring of low-concentration biomarkers or nucleic acids.

Improving Research Patient Data Repositories From a Health Data Industry Viewpoint.

Organizational, administrative, and educational challenges in establishing and sustaining biomedical data science infrastructures lead to the inefficient use of Research Patient Data Repositories (RPDRs). The challenges, including but not limited to deployment, sustainability, cost optimization, collaboration, governance, security, rapid response, reliability, stability, scalability, and convenience, restrict each other and may not be naturally alleviated through traditional hardware upgrades or protocol enhancements. This article attempts to borrow data science thinking and practices in the business realm, which we call the data industry viewpoint, to improve RPDRs.

Copper circuits fabricated on flexible polymer substrates by a high repetition rate femtosecond laser-induced selective local reduction of copper oxide nanoparticles.

In this work, copper circuits were fabricated on flexible polyimide (PI) substrates by high repetition rate femtosecond laser-induced selective local reduction of copper oxide nanoparticles (CuO NPs). The effects of laser pulse energy and laser scanning velocity on the quality of the copper circuit were studied. By optimizing laser processing parameters, we prepared a Cu circuit of a line width of 5.5 µm and an electrical resistivity of 130.9 µΩ·cm. The Cu/O atomic ratio of the Cu circuit reaches ∼10.6 and the proportion of Cu is 91.42%. We then studied the formation mechanism of the copper circuit by simulating the temperature field under the irradiation of high repetition rate femtosecond laser pulses. The results show that the thermochemical reduction reaction induced by the high repetition rate femtosecond laser reduces CuO NPs into Cu NPs. Under the thermal effect of the high repetition rate femtosecond laser, Cu NPs agglomerate and grow to form a uniform and continuous Cu circuit.

PJ34, a PARP1 inhibitor, attenuates acute allograft rejection after murine heart transplantation via regulating the CD4+ T lymphocyte response.

Acute allografts rejection is the most important factor causing allograft disability for many patients undergoing organ transplantation. PJ34, which is a specific inhibitor of poly(ADP-ribose) polymerase 1, is involved in immune regulation, may be effective in preventing acute cardiac rejection. We performed the models of abdominal heterotopic heart transplantation. PJ34 was injected intraperitoneally daily (20 mg/kg/day) starting the day after surgery. The severity of rejection was determined by histology. The mRNA expression levels of cytokines and transcription factors in the grafts were measured by quantitative polymerase chain reaction (qPCR). The proportion and number of T-cell subpopulations in the spleens were analyzed by flow cytometry. In vitro, the effect of PJ34 on allogeneic responses was investigated. We found treatment with PJ34 prolonged allograft survival compared with normal saline treatment. Compared with the control group, PJ34 treatment reduced the proportion of CD4+ IFN-γ+ and CD4+ IL-17A+ cells and increased the percent of CD4+ IL-4+ and CD4+ Foxp3+ cells in the spleens. In vitro, PJ34 treatment significantly inhibited the mRNA levels of IFN-γ and IL-17A and promoted the mRNA levels of TGF-ß and FOXP-3 in activated CD4+ T cells. Modulating the CD4+ T lymphocyte response with PJ34 could attenuate acute allografts rejection after murine heart transplantation. These findings indicate that PARP1 may be a promising therapeutic target to attenuate acute cardiac allograft rejection.

Measuring a Broad Spectrum of eHealth Skills in the Web 3.0 Context Using an eHealth Literacy Scale: Development and Validation Study.

BACKGROUND: eHealth literacy (EHL) refers to a variety of capabilities that enable individuals to obtain health information from electronic resources and apply it to solve health problems. With the digitization of health care and the wide availability of health apps, a more diverse range of eHealth skills is required to properly use such health facilities. Existing EHL measurements focus mainly on the skill of obtaining health information (Web 1.0), whereas skills for web-based interactions (Web 2.0) and self-managing health data and applying information (Web 3.0) have not been well measured. OBJECTIVE: This study aims to develop an EHL scale (eHLS) termed eHLS-Web3.0 comprising a comprehensive spectrum of Web 1.0, 2.0, and 3.0 skills to measure EHL, and evaluate its validity and reliability along with the measurement invariance among college students. METHODS: In study 1, 421 Chinese college students (mean age 20.5, SD 1.4 years; 51.8% female) and 8 health experts (mean age 38.3, SD 5.9 years; 87.5% female) were involved to develop the eHLS-Web3.0. The scale development included three steps: item pool generation, content validation, and exploratory factor analysis. In study 2, 741 college students (mean age 21.3, SD 1.4 years; 52.2% female) were recruited from 4 Chinese cities to validate the newly developed eHLS-Web3.0. The construct validity, convergent validity, concurrent validity, internal consistency reliability, test-retest reliability, and measurement invariance across genders, majors, and regions were examined by a series of statistical analyses, including confirmatory factor analysis (CFA) and multigroup CFAs using SPSS and Mplus software packages. RESULTS: Based on the item pool of 374 statements collected during the conceptual development, 24 items (4-10 items per subscale) were generated and adjusted after cognitive testing and content validity examination. Through exploratory factor analysis, a 3-factor eHLS-Web3.0 was finally developed, and it included acquisition (8 items), verification (6 items), and application (10 items). In study 2, CFAs supported the construct validity of the 24-item 3D eHLS-Web3.0 (χ2244=903.076, χ2244=3.701, comparative fit index=0.924, Tucker-Lewis index=0.914, root mean square error of approximation [RMSEA]=0.06, and standardized root mean residual [SRMR]=0.051). The average variance extracted (AVE) value of 0.58 and high correlation between eHLS-Web3.0 subscales and the eHealth Literacy Scale (r=0.725-0.880, P<.001) indicated the convergent validity and concurrent validity of the eHLS-Web3.0. The results also indicated satisfactory internal consistency reliability (α=.976, ρ=0.934-0.956) and test-retest reliability (r=0.858, P<.001) of the scale. Multigroup CFA demonstrated the 24-item eHLS-Web3.0 to be invariant at all configural, metric, strength, and structural levels across genders (female and male), majors (sport-related, medical, and general), and regions (Yinchuan, Kunming, Xiamen, and Beijing). CONCLUSIONS: The 24-item 3D eHLS-Web3.0 proved to be a reliable and valid measurement tool for EHL in the Web 3.0 context among Chinese college students.

Electrochemical Reflective Absorption Microscopy for Probing the Local Diffusion Behavior in the Electrochemical Interface.

Electrochemical interfaces determine the performance of electrochemical devices, including energy-related systems. An in-depth understanding of the heterogeneous interfaces requires in situ techniques with high sensitivity and high temporal and spatial resolution. We develop here an electrochemical reflective absorption microscope (EC-RAM) by using the absorption signals of reacting species with a reasonably good spatial resolution and high sensitivity. We systematically study the response of absorbance ( A) and its derivative, i.e. d A/d t, at different positions of the electrode surface and at electrodes with different sizes (50 µm, 500 µm, and 2 mm) both experimentally and theoretically. We find that the derivative cyclic voltabsorptometry (DCVA) frequently used to obtain the local current response in conventional electrochemical optical microscopy techniques is only applicable to reactions of surface species or solution species under linear diffusion control. For processes when the radial diffusion cannot be ignored, as in the case of a microelectrode or the edge of a large electrode, the DCVA curves show distinct diffusion behaviors for the electroactive species in different regions of the electrode, which cannot be directly related to the CV curves. When the radial diffusion dominates the reaction, CVA curves follow the same shape as the CV curves. The developed EC-RAM technique can be applied to extract in situ the local response of an electrochemical system during the dynamic reaction processes.

Characterization of gelsevirine metabolites in rat liver S9 by accurate mass measurements using high-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry.

RATIONALE: Gelsemium elegans Benth. belongs to the family Loganiaceae and is widely distributed in northern America, east Asia, and southeast Asia. It has attracted wide attention for its diverse biological effects and complex architectures. Gelsevirine is one of the major components in G. elegans. Compared with other alkaloids from G. elegans, gelsevirine exhibits equally potent anxiolytic effects but with less toxicity. However, the metabolism of gelsevirine has not been clearly elucidated. METHODS: The metabolism of gelsevirine was investigated using liver S9 fractions derived from rat liver homogenates by centrifugation at 9000 g. A rapid and accurate high-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (HPLC/QqTOF-MS) method was applied to characterize the gelsevirine metabolites. RESULTS: We discovered a total number of four metabolites of gelsevirine. The metabolic pathways of gelsevirine consisted of hydrogenation, N-demethylenation and oxidation in rat liver S9. CONCLUSIONS: This is the first study on the metabolism of gelsevirine. We proposed possible metabolic pathways of gelsevirine. These findings may warrant future studies of the in vivo metabolism of gelsemine in animals.

Identification of gelsemine metabolites in rat liver S9 by high-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry.

RATIONALE: Gelsemine has been extensively studied because of its anti-tumor, immunomodulatory, insecticidal itching and other significant effects. However, limited information on the pharmacokinetics and metabolism of gelsemine has been reported. Therefore, the purpose of the present study was to investigate the in vitro metabolism of gelsemine in rat liver S9 by using rapid and accurate high-performance liquid chromatography/ quadrupole-time-of-flight mass spectrometry (HPLC/QqTOF-MS). METHODS: The incubation mixture was processed with 15% trichloroacetic acid. Multiple scans of gelsemine metabolites and accurate mass measurements were automatically performed simultaneously through data-dependent acquisition in only 30 min. The structural elucidations of these metabolites were performed by comparing their changes in accurate molecular masses and product ions with those of the parent drug. RESULTS: Five metabolites of gelsemine were identified in rat liver S9. Of these, four metabolites of gelsemine were identified for the first time. The present results showed that the metabolic pathways of gelsemine are oxidation, demethylation, and dehydrogenation in rat liver S9. CONCLUSIONS: In this study, metabolites of gelsemine in liver S9 were identified and elucidated firstly using the HPLC/QqTOF-MS method. The proposed metabolic pathways of gelsemine in liver S9 will provide a basis for further studies of the in vivo metabolism of gelsemine in animals and humans.

Structural elucidation of koumine metabolites by accurate mass measurements using high-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry.

RATIONALE: Koumine is one of the major components of total alkaloids from Gelsemium. Koumine possesses a variety of interesting pharmacological effects, including anti-tumor, anti-inflammatory, and anxiolytic activities. It might be a promising lead drug because of its pharmacological activities and mild toxicity. However, little information is available on the metabolism of koumine. METHODS: A rapid and accurate high-performance liquid chromatography/quadrupole-time-of-flight (HPLC/QqTOF) mass spectrometry method was applied to characterize koumine metabolites. Multiple scans of koumine metabolites, which were formed in rat liver S9, were automatically performed simultaneously through auto MS/MS mode acquisition in only a 30-min analysis. The structural elucidation of these metabolites was performed by comparing their changes in accurate molecular masses and product ions with those of the parent drug or metabolites. RESULTS: As a result, a total of eleven metabolites of koumine were identified, of which nine new metabolites were found. The present results showed that the N-demethylenation, hydrogenation and the oxidation were the three main metabolic pathways of koumine. CONCLUSIONS: This was the first investigation of in vitro metabolism of koumine in rat liver S9 using a sensitive and specific HPLC/QqTOF-MS method. The possible metabolic pathways of koumine were tentatively proposed based on the structural elucidations of these metabolites. This work may be useful in the in vivo metabolism of koumine in animals and humans. Copyright © 2016 John Wiley & Sons, Ltd.

Acetanilide and bromoacetyl-lysine derivatives as activators for human histone deacetylase 8.

In the current study, seven compounds (i.e. 1-7) were found to be novel activators for the Nε-acetyl-lysine deacetylation reaction catalyzed by human histone deacetylase 8 (HDAC8). When assessed with the commercially available HDAC8 peptide substrate Fluor-de-Lys®-HDAC8 that harbors the unnatural 7-amino-4-methylcoumarin (AMC) residue immediately C-terminal to the Nε-acetyl-lysine residue to be deacetylated, our compounds exhibited comparable activation potency to that of TM-2-51, the strongest HDAC8 activator reported in the current literature. However, when assessed with an AMC-less peptide substrate derived from the native HDAC8 non-histone substrate protein Zinc finger protein ZNF318, while our compounds were all found to be able to activate HDAC8 deacetylation reaction, TM-2-51 was found not to be able to. Our compounds also seemed to be largely selective for HDAC8 over other classical HDACs. Moreover, treatment with the strongest activator among our compounds (i.e. 7) was found to decrease the KM of the above AMC-less HDAC8 substrate, while nearly maintaining the kcat of the HDAC8-catalyzed deacetylation on this substrate.

Identification of allocryptopine and protopine metabolites in rat liver S9 by high-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry.

RATIONALE: Allocryptopine (AL) and protopine (PR) have been extensively studied because of their anti-parasitic, anti-arrhythmic, anti-thrombotic, anti-inflammatory and anti-bacterial activity. However, limited information on the pharmacokinetics and metabolism of AL and PR has been reported. Therefore, the purpose of the present study was to investigate the in vitro metabolism of AL and PR in rat liver S9 using a rapid and accurate high-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (HPLC/QqTOFMS) method. METHODS: The incubation mixture was processed with 15% trichloroacetic acid (TCA). Multiple scans of AL and PR metabolites and accurate mass measurements were automatically performed simultaneously through data-dependent acquisition in only a 30-min analysis. The structural elucidations of these metabolites were performed by comparing their changes in accurate molecular masses and product ions with those of the precursor ion or metabolite. RESULTS: Eight and five metabolites of AL and PR were identified in rat liver S9, respectively. Among these metabolites, seven and two metabolites of AL and PR were identified in the first time, respectively. The demethylenation of the 2,3-methylenedioxy, the demethylation of the 9,10-vicinal methoxyl group and the 2,3-methylenedioxy group were the main metabolic pathways of AL and PR in liver S9, respectively. In addition, the cleavage of the methylenedioxy group of the drugs and subsequent methylation or O-demethylation were also the common metabolic pathways of drugs in liver S9. In addition, the hydroxylation reaction was also the metabolic pathway of AL. CONCLUSIONS: This was the first investigation of in vitro metabolism of AL and PR in rat liver S9. The detailed structural elucidations of AL and PR metabolites were performed using a rapid and accurate HPLC/QqTOFMS method. The metabolic pathways of AL and PR in rat were tentatively proposed based on these characterized metabolites and early reports. Copyright © 2016 John Wiley & Sons, Ltd.

Simple N(ε)-thioacetyl-lysine-containing cyclic peptides exhibiting highly potent sirtuin inhibition.

Transforming a linear pentapeptidic pan-SIRT1/2/3 inhibitor harboring the catalytic mechanism-based sirtuin inhibitory warhead N(ε)-thioacetyl-lysine into its side chain-to-side chain cyclized derivatives was able to furnish highly potent SIRT1/2/3 inhibition (low nM). This finding attests to the feasibility of developing structurally simple yet highly potent catalytic mechanism-based cyclic peptidic sirtuin inhibitors.

The chemical biology of sirtuins.

The sirtuin family of enzymes are able to catalyze the N(ε)-acyl-lysine deacylation reaction on histone and non-histone protein substrates. Over the past years since the discovery of its founding member (i.e. the yeast silent information regulator 2 (sir2) protein) in 2000, the sirtuin-catalyzed deacylation reaction has been demonstrated to play an important regulatory role in multiple crucial cellular processes such as transcription, DNA damage repair, and metabolism. This reaction has also been regarded as a current therapeutic target for human diseases such as cancer, and metabolic and neurodegenerative diseases. The unique ß-nicotinamide adenine dinucleotide (ß-NAD(+) or NAD(+))-dependent nature of the sirtuin-catalyzed deacylation reaction has also engendered extensive mechanistic studies, resulting in a mechanistic view of the enzyme chemistry supported by several lines of experimental evidence. On the journey toward these knowledge advances, chemical biological means have constituted an important functional arsenal; technically, a variety of chemical probes and modulators (inhibitors and activators) have been developed and some of them have been employed toward an enhanced mechanistic and functional (pharmacological) understanding of the sirtuin-catalyzed deacylation reaction. On the other hand, an enhanced mechanistic understanding has also facilitated the development of a variety of chemical probes and modulators. This article will review the tremendous accomplishments achieved during the past few years in the field of sirtuin chemical biology. It is hoped that this would also help to set a stage for how outstanding mechanistic and functional questions for the sirtuin-catalyzed deacylation reaction could be addressed in the future from the chemical biology perspective.

A Selective Cyclic Peptidic Human SIRT5 Inhibitor.

In the current study, we discovered that a side chain-to-side chain cyclic pentapeptide harboring a central N(ε)-carboxyethyl-thiocarbamoyl-lysine residue behaved as a strong and selective (versus human SIRT1/2/3/6) inhibitor against human SIRT5-catalyzed deacylation reaction. This compound was also found to be proteolytically much more stable than its linear counterpart. This compound could be a valuable lead for developing stronger, selective, metabolically stable, and cell permeable human SIRT5 inhibitors.

In Vivo Programmed Gene Expression Based on Artificial Quorum Networks.

The quorum sensing (QS) system, as a well-functioning population-dependent gene switch, has been widely applied in many gene circuits in synthetic biology. In our work, an efficient cell density-controlled expression system (QS) was established via engineering of the Vibrio fischeri luxI-luxR quorum sensing system. In order to achieve in vivo programmed gene expression, a synthetic binary regulation circuit (araQS) was constructed by assembling multiple genetic components, including the quorum quenching protein AiiA and the arabinose promoter ParaBAD, into the QS system. In vitro expression assays verified that the araQS system was initiated only in the absence of arabinose in the medium at a high cell density. In vivo expression assays confirmed that the araQS system presented an in vivo-triggered and cell density-dependent expression pattern. Furthermore, the araQS system was demonstrated to function well in different bacteria, indicating a wide range of bacterial hosts for use. To explore its potential applications in vivo, the araQS system was used to control the production of a heterologous protective antigen in an attenuated Edwardsiella tarda strain, which successfully evoked efficient immune protection in a fish model. This work suggested that the araQS system could program bacterial expression in vivo and might have potential uses, including, but not limited to, bacterial vector vaccines.