USP9X-mediated REV1 deubiquitination promotes lung cancer radioresistance via the action of REV1 as a Rad18 molecular scaffold for cystathionine γ-lyase.

BACKGROUND: Radioresistance is a key clinical constraint on the efficacy of radiotherapy in lung cancer patients. REV1 DNA directed polymerase (REV1) plays an important role in repairing DNA damage and maintaining genomic stability. However, its role in the resistance to radiotherapy in lung cancer is not clear. This study aims to clarify the role of REV1 in lung cancer radioresistance, identify the intrinsic mechanisms involved, and provide a theoretical basis for the clinical translation of this new target for lung cancer treatment. METHODS: The effect of targeting REV1 on the radiosensitivity was verified by in vivo and in vitro experiments. RNA sequencing (RNA-seq) combined with nontargeted metabolomics analysis was used to explore the downstream targets of REV1. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to quantify the content of specific amino acids. The coimmunoprecipitation (co-IP) and GST pull-down assays were used to validate the interaction between proteins. A ubiquitination library screening system was constructed to investigate the regulatory proteins upstream of REV1. RESULTS: Targeting REV1 could enhance the radiosensitivity in vivo, while this effect was not obvious in vitro. RNA sequencing combined with nontargeted metabolomics revealed that the difference result was related to metabolism, and that the expression of glycine, serine, and threonine (Gly/Ser/Thr) metabolism signaling pathways was downregulated following REV1 knockdown. LC-MS/MS demonstrated that REV1 knockdown results in reduced levels of these three amino acids and that cystathionine γ-lyase (CTH) was the key to its function. REV1 enhances the interaction of CTH with the E3 ubiquitin ligase Rad18 and promotes ubiquitination degradation of CTH by Rad18. Screening of the ubiquitination compound library revealed that the ubiquitin-specific peptidase 9 X-linked (USP9X) is the upstream regulatory protein of REV1 by the ubiquitin-proteasome system, which remodels the intracellular Gly/Ser/Thr metabolism. CONCLUSION: USP9X mediates the deubiquitination of REV1, and aberrantly expressed REV1 acts as a scaffolding protein to assist Rad18 in interacting with CTH, promoting the ubiquitination and degradation of CTH and inducing remodeling of the Gly/Ser/Thr metabolism, which leads to radioresistance. A novel inhibitor of REV1, JH-RE-06, was shown to enhance lung cancer cell radiosensitivity, with good prospects for clinical translation.

Transcriptome analysis of Kluyveromyces marxianus under succinic acid stress and development of robust strains.

Kluyveromyces marxianus has become an attractive non-conventional yeast cell factory due to its advantageous properties such as high thermal tolerance and rapid growth. Succinic acid (SA) is an important platform molecule that has been applied in various industries such as food, material, cosmetics, and pharmaceuticals. SA bioproduction may be compromised by its toxicity. Besides, metabolite-responsive promoters are known to be important for dynamic control of gene transcription. Therefore, studies on global gene transcription under various SA concentrations are of great importance. Here, comparative transcriptome changes of K. marxianus exposed to various concentrations of SA were analyzed. Enrichment and analysis of gene clusters revealed repression of the tricarboxylic acid cycle and glyoxylate cycle, also activation of the glycolysis pathway and genes related to ergosterol synthesis. Based on the analyses, potential SA-responsive promoters were investigated, among which the promoter strength of IMTCP2 and KLMA_50231 increased 43.4% and 154.7% in response to 15 g/L SA. In addition, overexpression of the transcription factors Gcr1, Upc2, and Ndt80 significantly increased growth under SA stress. Our results benefit understanding SA toxicity mechanisms and the development of robust yeast for organic acid production. KEY POINTS: • Global gene transcription of K. marxianus is changed by succinic acid (SA) • Promoter activities of IMTCP2 and KLMA_50123 are regulated by SA • Overexpression of Gcr1, Upc2, and Ndt80 enhanced SA tolerance.

Agrimol B alleviates cisplatin-induced acute kidney injury by activating the Sirt1/Nrf2 signaling pathway in mice.

Cisplatin (CDDP) is a widely used chemotherapeutic agent that has remarkable antineoplastic effects. However, CDDP can cause severe acute kidney injury (AKI), which limits its clinical application. Agrimol B is the main active ingredient found in Agrimonia pilosa Ledeb and has a variety of pharmacological activities. The effect of agrimol B on CDDP-induced renal toxicity has not been determined. To investigate whether agrimol B has a protective effect against CDDP-induced AKI, we first identify Sirtuin 1 (Sirt1) as a critical target protein of agrimol B in regulating AKI through network pharmacology analysis. Subsequently, the AKI mouse model is induced by administering a single dose of CDDP via intraperitoneal injection. By detecting the serum urea nitrogen and creatinine levels, as well as the histopathological changes, we confirm that agrimol B effectively reduces CDDP-induced AKI. In addition, treatment with agrimol B counteracts the increase in renal malondialdehyde level and the decrease in superoxide dismutase (SOD), catalase and glutathione levels induced by CDDP. Moreover, western blot results reveal that agrimol B upregulates the expressions of Sirt1, SOD2, nuclear factor erythroid2-related factor 2, and downstream molecules, including heme oxygenase 1 and NAD(P)H quinone dehydrogenase 1. However, administration of the Sirt1 inhibitor EX527 abolishes the effects of agrimol B. Finally, we establish a tumor-bearing mouse model and find that agrimol B has a synergistic antitumor effect with CDDP. Overall, agrimol B attenuates CDDP-induced AKI by activating the Sirt1/Nrf2 signaling pathway to counteract oxidative stress, suggesting that this compound is a potential therapeutic agent for the treatment of CDDP-induced AKI.

Prevalence and clonal diversity of carbapenem-resistant Klebsiella pneumoniae causing neonatal infections: A systematic review of 128 articles across 30 countries.

BACKGROUND: Klebsiella pneumoniae is the most common pathogen causing neonatal infections, leading to high mortality worldwide. Along with increasing antimicrobial use in neonates, carbapenem-resistant K. pneumoniae (CRKP) has emerged as a severe challenge for infection control and treatment. However, no comprehensive systematic review is available to describe the global epidemiology of neonatal CRKP infections. We therefore performed a systematic review of available data worldwide and combined a genome-based analysis to address the prevalence, clonal diversity, and carbapenem resistance genes of CRKP causing neonatal infections. METHODS AND FINDINGS: We performed a systematic review of studies reporting population-based neonatal infections caused by CRKP in combination with a genome-based analysis of all publicly available CRKP genomes with neonatal origins. We searched multiple databases (PubMed, Web of Science, Embase, Ovid MEDLINE, Cochrane, bioRxiv, and medRxiv) to identify studies that have reported data of neonatal CRKP infections up to June 30, 2022. We included studies addressing the prevalence of CRKP infections and colonization in neonates but excluded studies lacking the numbers of neonates, the geographical location, or independent data on Klebsiella or CRKP isolates. We used narrative synthesis for pooling data with JMP statistical software. We identified 8,558 articles and excluding those that did not meet inclusion criteria. We included 128 studies, none of which were preprints, comprising 127,583 neonates in 30 countries including 21 low- and middle-income countries (LMICs) for analysis. We found that bloodstream infection is the most common infection type in reported data. We estimated that the pooled global prevalence of CRKP infections in hospitalized neonates was 0.3% (95% confidence interval [CI], 0.2% to 0.3%). Based on 21 studies reporting patient outcomes, we found that the pooled mortality of neonatal CRKP infections was 22.9% (95% CI, 13.0% to 32.9%). A total of 535 neonatal CRKP genomes were identified from GenBank including Sequence Read Archive, of which 204 were not linked to any publications. We incorporated the 204 genomes with a literature review for understanding the species distribution, clonal diversity, and carbapenemase types. We identified 146 sequence types (STs) for neonatal CRKP strains and found that ST17, ST11, and ST15 were the 3 most common lineages. In particular, ST17 CRKP has been seen in neonates in 8 countries across 4 continents. The vast majority (75.3%) of the 1,592 neonatal CRKP strains available for analyzing carbapenemase have genes encoding metallo-ß-lactamases and NDM (New Delhi metallo-ß-lactamase) appeared to be the most common carbapenemase (64.3%). The main limitation of this study is the absence or scarcity of data from North America, South America, and Oceania. CONCLUSIONS: CRKP contributes to a considerable number of neonatal infections and leads to significant neonatal mortality. Neonatal CRKP strains are highly diverse, while ST17 is globally prevalent and merits early detection for treatment and prevention. The dominance of blaNDM carbapenemase genes imposes challenges on therapeutic options in neonates and supports the continued inhibitor-related drug discovery.

Activated FeS2 @NiS2 Core-Shell Structure Boosting Cascade Reaction for Superior Electrocatalytic Oxygen Evolution.

Unlike single-step reactions, multi-step reactions can be greatly facilitated only if all the intermediate reactions can be catalyzed simultaneously and progressively. Herein, the theoretical analysis and experiments to illustrate the superiority of the cascade oxygen evolution reaction (OER) are conducted. As different OER intermediate reactions demand Fex Ni1-x OOH with altered Fe/Ni ratios, gradient Fe-doped NiOOH can be an ideal electrocatalyst for the efficient cascade OER in line. Fine controlling of the nucleation sequence of iron and nickel sulfides leads to a FeS2 @NiS2 core-shell structure. The activated outward diffusion of Fe dopants results in the gradient Fe/Ni ratios in the Fex Ni1-x OOH shell, where a cascade OER can happen. Electrochemical tests suggest that the FeS2 @NiS2 only needs an overpotential of 237 mV to reach the current density of 10 mA cm-2 , with fast reaction kinetics and good stability.

Pb speciation and elemental distribution in leeks by micro X-ray fluorescence and X-ray absorption near-edge structure.

Vegetables are crucial to a human diet as they supply the body with essential vitamins, minerals, etc. Heavy metals that accumulate in plants consequently enter the food chain and endanger people's health. Studying the spatial distribution and chemical forms of elements in plant/vegetable tissues is vital to comprehending the potential interactions between elements and detoxification mechanisms. In this study, leek plants and soil from vegetable gardens near lead-zinc mines were collected and cultivated with 500 mg L-1 PbNO3 solutions for three weeks. Micro X-ray fluorescence was used to map the distribution of Pb and other chemical elements in leek roots, and X-ray absorption near-edge spectroscopy was used to assess the Pb speciation in leek roots and leaves. These findings demonstrated that Pb, Cu, Mn, Cr, Ti and Fe were detected in the outer rings of the root's cross section, and high-intensity points were observed in the epidermis. Zn, K and Ca, on the other hand, were distributed throughout the root's cross section. Leek root and leaf contained significant quantities of lead phosphate and basic lead carbonate at more than 80%, followed by lead sulfide (19%) and lead stearate (11.1%). The capacity of leek roots to convert ambient lead into precipitated lead and fix it on the root epidermis and other inner surfaces is a key mechanism for reducing the toxic effects of Pb.

Characterization of a novel carbapenem-hydrolysing ß-lactamase OXA-1041 in Escherichia coli.

BACKGROUND: We found a carbapenem-resistant Escherichia coli without known carbapenemase-encoding genes and performed a study to identify the possible new carbapenemase. METHODS: The production of carbapenemase was examined using the modified carbapenem inactivation method. The strain was subjected to short- and long-read genome sequencing and the complete genome was obtained by hybrid assembly. The gene encoding a potential new OXA-type carbapenemase was cloned. The enzyme was purified and was then subjected to kinetic assays. Molecular docking analysis of the enzyme was performed using the MOE software suite. Mating experiments were attempted to obtain the plasmid carrying the corresponding gene. RESULTS: We identified and characterized a novel class D carbapenem-hydrolysing ß-lactamase, OXA-1041, in a carbapenem-resistant E. coli clinical strain. OXA-1041 had 89.77% (237/264) amino acid identity with OXA-427, a known carbapenemase. By cloning in an E. coli laboratory strain, blaOXA-1041 was found to reduce susceptibility to ertapenem by 16 times (MIC 0.25 versus 0.016 mg/L) and meropenem by four times (MIC 0.06 versus 0.016 mg/L) but did not significantly reduce susceptibility to imipenem and doripenem. Enzyme kinetic measurement of purified OXA-1041 showed that OXA-1041 could hydrolyse ertapenem and meropenem with a turnover number (kcat)/Michaelis constant (KM) of 8.57 and 3.63 mM-1s-1, respectively. The complete genome contained a single plasmid (223 341 bp, IncF, containing five replicons), which was self-transmissible. blaOXA-1041 was downstream of insertion sequence ISCR1 and there were three tandem copies of ISCR1-blaOXA-1041-creDΔ (encoding an envelope protein) on this plasmid. CONCLUSIONS: The above findings suggest OXA-1041 is a new plasmid-encoded carbapenemase with preferential activity against ertapenem.

Janus kinase inhibitor Tofacitinib alleviated acute hepatitis induced by lipopolysaccharide/D-galactosamine in mice.

BACKGROUND: The Janus kinase (JAK) is a crucial intracellular signaling hub for numerous cytokines, which is extensively involved in the activation of inflammatory cascade and the induction of inflammatory injury. JAK inhibition provides protective effects in several inflammation-based disorders, but the potential effects of JAK inhibitor in inflammation-based acute hepatitis remain to be investigated. METHODS AND RESULTS: Acute hepatitis is induced by Lipopolysaccharide/D-galactosamine (LPS/D-Gal) in mice with or without the JAK inhibitor Tofacitinib administration. The degree of liver injury, the production of pro-inflammatory cytokines and induction of hepatocytes apoptosis were determined. The results indicated that treatment with Tofacitinib decreased the levels of aminotransferases, attenuated the histological abnormalities in liver and decreased the plasma levels of TNF-α and IL-6 in LPS/D-Gal-insulted mice. In addition, Tofacitinib suppressed the activation of the caspase cascade, decreased the level of cleaved caspase-3, and reduced the count of TUNEL-positive cells. CONCLUSION: Treatment with Tofacitinib alleviated LPS/D-Gal-induced acute hepatitis. JAK maybe become a promising target for the control of inflammation-based liver disorders.

Emerging functions and applications of exosomes in oral squamous cell carcinoma.

Oral squamous cell carcinoma is the most common phenotype in pathology, which accounts for 80% of all oral cancers. The therapeutic methods of oral squamous cell carcinoma include surgical excision, chemotherapy, and radiotherapy. Whereas, the high recurrence rate and poor prognosis lead to a 5-year survival rate less than 50%. In order to explore more therapeutic strategies of oral squamous cell carcinoma, the relevant risk factors, mechanisms, and diagnostics are widely detected. The various exosome-mediated biological effects on the development of oral squamous cell carcinoma have drawn lots of attention. Exosomes, a kind of extracellular vesicles secreted from host cells and transferred to other cells, show great potential in the regulations of tumorigenesis, progression, and metastasis on oral squamous cell carcinoma. Moreover, some studies reported that the exosomes could interact with tumor microenvironment and be applied to diagnosis or therapy of oral squamous cell carcinoma. In this work, we will summarize the frontier studies of exosomes in the tumor growth, tumor-associated angiogenesis, invasion, and metastasis of oral squamous cell carcinoma, and then probe the current biological functions and applications of exosomes and exosome-derived materials for the therapeutic strategies of oral squamous cell carcinoma, which would help us to update the understanding of exosomes in oral squamous cell carcinoma.

Insight into the Fe atom-FeS cluster synergistic catalysis mechanism for the oxygen evolution reaction in NiS2-based electrocatalysts.

The development of highly active oxygen evolution reaction (OER) catalysts with fast kinetics is crucial for the advancement of clean energy and fuel conversion to achieve a sustainable energy future. Recently, the synergistic effect of single-atom doping and multicomponent clusters has been demonstrated to significantly improve the catalytic activity of materials. However, such synergistic effects involving multi-electron and proton transfer processes are quite complex and many crucial mechanistic details need be well comprehended. We ingeniously propose a catalyst, (Fed-FeSc)@NiS2 (d stands for doping and c stands for clustering), with Fe and FeS acting synergistically on a NiS2 substrate. Specifically, fully dynamic monitoring of multiple active sites at the (Fed-FeSc)@NiS2 interface using metadynamics is innovatively performed. The results show that the rate determining step value at the overpotential of 1.23 V for the synergistic (Fed-FeSc)@NiS2 is 1.55 V, decreased by 6.67% and 35.29% compared to those of the independently acting single-atom doping and multi-clusters. The unique synergistic structure dramatically increases the d-band centre of the Fe site (-1.45 eV), endowing (Fed-FeSc)@NiS2 with more activity than conventional commercial Ir-C catalysts. This study provides insights into the synergistic effects of single-atom doping and multi-component clusters, leading to exploratory inspiration for the design of highly efficient OER catalysts.

Serum uric acid and outcome in hospitalized elderly patients with chronic heart failure through the whole spectrum of ejection fraction phenotypes.

INTRODUCTION: Elevated serum uric acid (SUA) levels have been associated with poor outcome in patients with heart failure (HF). Uric acid is associated with inflammation and microvascular dysfunction, which may differentially affect left ventricular ejection fraction (EF) phenotypes. We aimed to identify the role of SUA across EF phenotypes in hospitalized elderly patients with chronic HF. METHODS: We analyzed 1355 elderly patients who were diagnosed with chronic HF. All patients had SUA levels measured within the first 24 h following admission. Patients with left ventricle EF were categorized as having HF with reduced EF (HFrEF, EF < 40%), HF with mid-range EF (HFmrEF, 40%≦LVEF ≦ 49%) or HF with preserved EF (HFpEF, LVEF ≥ 50%). Endpoints were cardiovascular death, HF rehospitalization, and their composite. The median follow-up period was 18 months. RESULTS: Compared with the lowest SUA quartile, the highest SUA quartile was significantly associated with the endpoints (adjusted HR: 2.404, 95% CI: 1.178-4.906, P = 0.016; HR: 1.418, 95% CI: 1.021-1.971, P = 0.037; HR: 1.439, 95% CI: 1.049-1.972, P = 0.024, respectively). After model adjustment, a significant association of SUA with cardiovascular death and the composite endpoint persisted among HFrEF and HFmrEF patients in the highest SUA quartile (P < 0.05 for all). CONCLUSIONS: In hospitalized elderly patients with chronic HF, SUA is an independent predictor of adverse outcomes, which can be seen in HFrEF and HFmrEF patients.

P4HA1, transcriptionally activated by STAT1, promotes esophageal cancer progression.

Esophageal cancer (EC) is one of the most frequent cancers with a higher mortality worldwide. Although prolyl 4-hydroxylase alpha polypeptide I (P4HA1) is involved in various human malignancies, the function of P4HA1 in EC remains unclear. The mRNA and protein expressions were assessed by quantitative real-time polymerase chain reaction, western blot and immunohistochemistry. CCK8 assay was used to detect EC cell viability. Cell proliferation was analyzed by colony formation and ethynyl-2'-deoxyuridine assays. In addition, flow cytometry and TdT-mediated dUTP nick-end labeling staining were performed to detect cell apoptosis. Masson's trichrome staining was used to assess the collagen fiber level in tumor tissues. The interaction between STAT1 and P4HA4 was analyzed using ChIP, dual-luciferase reporter gene and Y1H assays. P4HA1 was overexpressed in EC, and its knockdown suppressed EC cell proliferation and collagen synthesis and increased cell apoptosis. Meanwhile, P4HA1 knockdown could repress EC tumor growth in vivo. Our further research displayed that STAT1 promoted P4HA1 expression by interacting with P4HA1 promoter. As expected, P4HA1 overexpression abolished STAT1 knockdown's repression on EC cell malignant behaviors. Our research proved that P4HA1 was transcriptionally activated by STAT1, thereby promoting EC progression.

Virulence factors, antimicrobial resistance and phylogeny of bovine mastitis-associated Streptococcus dysgalactiae.

We carried out a thorough genetic evaluation of Streptococcus dysgalactiae isolated from clinical bovine mastitis cases and performed a phylogenetic analysis to represent the evolutionary relationship between S. dysgalactiae sequences. A total of 35 S. dysgalactiae strains were isolated from cases of clinical mastitis identified at a large commercial dairy farm located near Ithaca, New York. Whole-genome sequencing identified twenty-six antibiotic resistance genes, four of which were acquired genes, in addition to fifty virulence genes. Multi-locus sequence typing detected three new sequence types (STs). We conclude that a high proportion of this microorganism carries multiple virulence determinants and resistance genes, and that this indicates its potential to cause mastitis. Eight different STs were identified, of which ST453 (n = 17) was the most prevalent and ST714, ST715, ST716 were novel STs.

A Differential Confocal Sensor for Simultaneous Position and Slope Acquisitions Based on a Zero-Crossing Prediction Algorithm.

A new sensor type is proposed to accurately detect the surface profiles of three-dimensional (3D) free-form surfaces. This sensor is based on the single-exposure, zero-crossing method and is used to measure position and angle simultaneously. First, the field intensity distribution in the posterior focal plane of the confocal microscope's objective was modeled accurately. Second, because the camera needs to trigger acquisition when the surface (to be measured) reaches the focal position of the sensor, a zero-crossing prediction method based on a sliding window was proposed. Third, a fast, spatially convergent, peak-extraction algorithm was proposed to improve the accuracy and efficiency of peak extraction. This scheme reduces system installation and adjustment difficulties, and the single-exposure, zero-crossing method achieves high-speed, real-time image acquisitions. The experimental results indicate that the average error of the zero-crossing prediction system was 17.63 nm, the average error of the tilt degree measurement was 0.011° in the range of 0-8°, and the prediction error of the tilt direction measurement was 0.089° in the range of 0-360°. The sensor can measure the slope and can be potentially used for 3D surface precision detection.

Comparative genomic analyses of Polymyxin-resistant Enterobacteriaceae strains from China.

BACKGROUND: Mobile colistin resistance like gene (mcr-like gene) is a new type of polymyxin resistance gene that can be horizontally transferred in the Enterobacteriaceae. This has brought great challenges to the treatment of multidrug-resistant Escherichia coli and K. pneumoniae. RESULTS: K. pneumoniae 16BU137 and E. coli 17MR471 were isolated from the bus and subway handrails in Guangzhou, China. K. pneumoniae 19PDR22 and KP20191015 were isolated from patients with urinary tract infection and severe pneumonia in Anhui, China. Sequence analysis indicated that the mcr-1.1 gene was present on the chromosome of E. coli 17MR471, and the gene was in the gene cassette containing pap2 and two copies of ISApl1.The mcr-1.1 was found in the putative IncX4 type plasmid p16BU137_mcr-1.1 of K. pneumoniae 16BU137, but ISApl1 was not found in its flanking sequence. Mcr-8 variants were found in the putative IncFIB/ IncFII plasmid pKP20191015_mcr-8 of K. pneumoniae KP20191015 and flanked by ISEcl1 and ISKpn26. CONCLUSION: This study provides timely information on Enterobacteriaceae bacteria carrying mcr-like genes, and provides a reference for studying the spread of mcr-1 in China and globally.

Carriage of distinct blaKPC-2 and blaOXA-48 plasmids in a single ST11 hypervirulent Klebsiella pneumoniae isolate in Egypt.

BACKGROUND: Carbapenem-resistant hypervirulent K. pneumoniae (CR-hvKP) causes serious infections with significant morbidity and mortality. However, the epidemiology and transmission mechanisms of CR-hvKP and the corresponding carbapenem-resistant plasmids require further investigation. Herein, we have characterized an ST11 K. pneumoniae strain EBSI041 from the blood sample encoding both hypervirulence and carbapenem resistance phenotypes from a patient in Egypt. RESULTS: K. pneumoniae strain EBSI041 showed multidrug-resistance phenotypes, where it was highly resistant to almost all tested antibiotics including carbapenems. And hypervirulence phenotypes of EBSI041 was confirmed by the model of Galleria mellonella infection. Whole-genome sequencing analysis showed that the hybrid plasmid pEBSI041-1 carried a set of virulence factors rmpA, rmpA2, iucABCD and iutA, and six resistance genes aph(3')-VI, armA, msr(E), mph(E), qnrS, and sul2. Besides, blaOXA-48 and blaSHV-12 were harboured in a novel conjugative IncL-type plasmid pEBSI041-2. The blaKPC-2-carrying plasmid pEBSI041-3, a non-conjugative plasmid lacking the conjugative transfer genes, could be transferred with the help of pEBSI041-2, and the two plasmids could fuse into a new plasmid during co-transfer. Moreover, the emergence of the p16HN-263_KPC-like plasmids is likely due to the integration of pEBSI041-3 and pEBSI041-4 via IS26-mediated rearrangement. CONCLUSION: To the best of our knowledge, this is the first report on the complete genome sequence of KPC-2- and OXA-48-coproducing hypervirulent K. pneumoniae from Egypt. These results give new insights into the adaptation and evolution of K. pneumoniae during nosocomial infections.

Fluorescein clearance kinetics in blood and bile indicates hepatic ischemia-reperfusion injury in rats.

Quantitative measurement of the degree of hepatic ischemia-reperfusion injury (IRI) is crucial for developing therapeutic strategies for its treatment. We hypothesized that clearance of fluorescent dye through bile metabolism may reflect the degree of hepatic IRI. In this study, we investigated sodium fluorescein clearance kinetics in blood and bile for quantifying the degree of hepatic IRI. Warm ischemia times (WITs) of 0, 30, or 60 min followed by 1 h or 4 h of reperfusion, were applied to the median and lateral lobes of the liver in Sprague-Dawley rats. Subsequently, 2 mg/kg of sodium fluorescein was injected intravenously, and blood and bile samples were collected over 60 min to measure fluorescence intensities. The bile-to-plasma fluorescence ratios demonstrated an inverse correlation with WIT and were distinctly lower in the 60-min WIT group than in the control or 30-min WIT groups. Bile-to-plasma fluorescence ratios displayed superior discriminability for short versus long WITs when measured 1 h after reperfusion versus 4 h. We conclude that the bile-to-blood ratio of fluorescence after sodium fluorescein injection has the potential to enable the quantification of hepatic IRI severity.NEW & NOTEWORTHY Previous attempts to use fluorophore clearance to test liver function have relied on a single source of data. However, the kinetics of substrate processing via bile metabolism include decreasing levels in blood and increasing levels in bile. Thus, we analyzed data from blood and bile to better reflect fluorescein clearance kinetics.

Inhibition of NAD kinase elevates the hepatic NAD+ pool and alleviates acetaminophen-induced acute liver injury in mice.

Acetaminophen (APAP) overdose induces acute liver injury (ALI), even acute liver failure (ALF). There is a significant unmet need to furtherly elucidate the mechanisms and find new therapeutic target. Recently, emerging evidence indicates that nicotinamide adenine dinucleotide (NAD+) plays a crucial role in APAP-induced ALI. Herein, we firstly investigated the protein expression of NAD kinase (NADK), as the rate-limiting enzyme converting NAD+ to nicotinamide adenine dinucleotide phosphate (NADP+), and found it was positively correlated with APAP-induced ALI in a dose- and time-dependent manner. Additionally, supplementation of N-acetylcysteine (NAC), known as an antidote of APAP, mitigated the ALI and downregulated the expression of NADK which was also in a dose-dependent manner. Moreover, pretreatment with methotrexate (MTX), the inhibitor of NADK, attenuated the levels of transaminases, alleviated morphological abnormalities, and improved oxidative stress triggered by APAP overdose, which was attributed to elevated hepatic NAD+ pool. Subsequently, the increased NAD+ upregulated the expression of Sirt1, SOD2 and attenuated DNA damage. Collectively, elevated expression of NADK is related to APAP-induced ALI, and inhibition of NADK alleviates the ALI through elevating liver NAD+ level and improving antioxidant capacity.

Immune response gene 1 deficiency impairs Nrf2 activation and aggravates liver fibrosis in mice.

A growing body of evidence suggests that metabolic events play essential roles in the development of liver fibrosis. Immune response gene 1 (IRG1) catalyzes the generation of itaconate, which function as a metabolic checkpoint under several pathological circumstances. In the present study, the hepatic level of IRG1 was determined in mice with carbon tetrachloride (CCl4)-induced liver fibrosis. And then the pathological significance of IRG1 and the pharmacological potential of 4-octyl itaconate (4-OI), a cell-permeable derivate of itaconate, in liver fibrosis were investigated in mice. The results indicated that the hepatic level of IRG1 was upregulated in mice with liver fibrosis. CCl4-induced formation of fibrotic septa and deposition of collagen was aggravated in IRG1 KO mice. IRG1 deletion also resulted in increased expression of transforming growth factor beta 1 (TGF-ß1), enhanced phosphorylation of Smad3, elevated level of alpha smooth muscle actin (α-SMA) and hydroxyproline, which were associated with compromised activation of nuclear erythroid 2-related factor 2 (Nrf2)-mediated antioxidant system and exacerbated oxidative stress. Interestingly, supplementation with 4-OI activated Nrf2 pathway, suppressed TGF-ß1 signaling and attenuated fibrogenesis. Our data indicated that upregulation of IRG1 might function as a protective response during the development of liver fibrosis, and 4-OI might have potential value for the pharmacological intervention of liver fibrosis.

Ti3 C2 TX MXene Modified with ZnTCPP with Bacteria Capturing Capability and Enhanced Visible Light Photocatalytic Antibacterial Activity.

Light-assisted antibacterial therapy is a promising alternative to antibiotic therapy due to the high antibacterial efficacy without bacterial resistance. Recent research has mainly focused on the use of near-infrared light irradiation to kill bacteria by taking advantage of the synergistic effects rendered by hyperthermia and radical oxygen species. However, photocatalytic antibacterial therapy excited by visible light is more convenient and practical, especially for wounds. Herein, a visible light responsive organic-inorganic hybrid of ZnTCPP/Ti3 C2 TX is designed and fabricated to treat bacterial infection with antibacterial efficiency of 99.86% and 99.92% within 10 min against Staphylococcus aureus and Escherichia coli, respectively. The porphyrin-metal complex, ZnTCPP, is assembled on the surface of Ti3 C2 TX MXene to capture bacteria electrostatically and the Schottky junction formed between Ti3 C2 TX and ZnTCPP promotes visible light utilization, accelerates charge separation, and enhances the mobility of photogenerated charges, and finally increases the photocatalytic activity. As a result of the excellent bacteria capturing ability and photocatalytic antibacterial effects, ZnTCPP/Ti3 C2 TX exposed to visible light has excellent antibacterial properties in vitro and in vivo. Therefore, organic-inorganic materials that have been demonstrated to possess good biocompatibility and enhance wound healing have large potential in bio-photocatalysis, antibacterial therapy, as well as antibiotics-free treatment of wounds.