Intracellular infection-responsive macrophage-targeted nanoparticles for synergistic antibiotic immunotherapy of bacterial infection.

Intracellular bacteria are considered to play a key role in the failure of bacterial infection therapy and increase of antibiotic resistance. Nanotechnology-based drug delivery carriers have been receiving increasing attention for improving the intracellular antibacterial activity of antibiotics, but are accompanied by disadvantages such as complex preparation procedures, lack of active targeting, and monotherapy, necessitating further design improvements. Herein, nanoparticles targeting bacteria-infected macrophages are fabricated to eliminate intracellular bacterial infections via antibiotic release and upregulation of intracellular reactive oxygen species (ROS) levels and proinflammatory responses. These nanoparticles were formed through the reaction of the amino group on selenocystamine dihydrochloride and the aldehyde group on oxidized dextran (ox-Dex), which encapsulates vancomycin (Van) through hydrophobic interactions. These nanoparticles could undergo targeted uptake by macrophages via endocytosis and respond to the bacteria-infected intracellular microenvironment (ROS and glutathione (GSH)) for controlled release of antibiotics. Furthermore, these nanoparticles could consume intracellular GSH and promote a significant increase in the level of ROS in macrophages, subsequently up-regulating the proinflammatory response to reinforce antibacterial activity. These nanoparticles can accelerate bacteria-infected wound healing. In this work, nanoparticles were fabricated for bacteria-infected macrophage-targeted and microenvironment-responsive antibiotic delivery, cellular ROS generation, and proinflammatory up-regulation activity to eliminate intracellular bacteria, which opens up a new possibility for multifunctional drug delivery against intracellular infection.

Cascade-Targeted Nanoplatforms for Synergetic Antibiotic/ROS/NO/Immunotherapy against Intracellular Bacterial Infection.

Intracellular bacteria in dormant states can escape the immune response and tolerate high-dose antibiotic treatment, leading to severe infections. To overcome this challenge, cascade-targeted nanoplatforms that can target macrophages and intracellular bacteria, exhibiting synergetic antibiotic/reactive oxygen species (ROS)/nitric oxide (NO)/immunotherapy, were developed. These nanoplatforms were fabricated by encapsulating trehalose (Tr) and vancomycin (Van) into phosphatidylserine (PS)-coated poly[(4-allylcarbamoylphenylboric acid)-ran-(arginine-methacrylamide)-ran-(N,N'-bisacryloylcystamine)] nanoparticles (PABS), denoted as PTVP. PS on PTVP simulates a signal of "eat me" to macrophages to promote cell uptake (the first-step targeting). After the uptake, the nanoplatform in the acidic phagolysosomes could release Tr, and the exposed phenylboronic acid on the nanoplatform could target bacteria (the second-step targeting). Nanoplatforms can release Van in response to infected intracellular overexpressed glutathione (GSH) and weak acid microenvironment. l-arginine (Arg) on the nanoplatforms could be catalyzed by upregulated inducible nitric oxide synthase (iNOS) in the infected macrophages to generate nitric oxide (NO). N,N'-Bisacryloylcystamine (BAC) on nanoplatforms could deplete GSH, allow the generation of ROS in macrophages, and then upregulate proinflammatory activity, leading to the reinforced antibacterial capacity. This nanoplatform possesses macrophage and bacteria-targeting antibiotic delivery, intracellular ROS, and NO generation, and pro-inflammatory activities (immunotherapy) provides a new strategy for eradicating intracellular bacterial infections.

Metabolism of Phenolic Compounds and Antioxidant Activity in Different Tissue Parts of Post-Harvest Chive (Allium schoenoprasum L.).

Chive (Allium schoenoprasum L.) has a strong antioxidant property as it contains abundant phenolic compounds and ascorbic acid. In the present study, we investigated the metabolism of phenolic compounds and the change in antioxidant activity in different tissue parts of post-harvest chives. The results showed that compared with the bottom white part (BW), the round green part (RG) exhibited significantly higher contents of phenolic compounds, increased enzyme activities and enhanced antioxidant activities, indicating that phenolic compounds were mainly synthesised in RG. The expression levels of genes such as phenylalanine ammonia-lyase, cinnamate 4-hydroxylase and 4-coumaroyl-CoA ligase and their corresponding enzyme activities rapidly decreased in RG, whereas they were maintained in BW, suggesting that senescence occurred more rapidly in RG than in BW. Our study provides a theoretical basis for further research into and development of different parts of Allium plants and offers a basis for consumers' nutritional considerations.

Dual cross-linked COL1/HAp bionic gradient scaffolds containing human amniotic mesenchymal stem cells promote rotator cuff tendon-bone interface healing.

The tendon-bone interface heals through scar tissue, while the lack of a natural interface gradient structure and collagen fibre alignment leads to the occurrence of retearing. Therefore, the promotion of tendon healing has become the focus of regenerative medicine. The purpose of this study was to develop a gradient COL1/ hydroxyapatite (HAp) biomaterial loaded with human amniotic mesenchymal stem cells (hAMSCs). The performance of common cross-linking agents, Genipin, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS), and dual cross-linked materials were compared to select the best cross-linking mechanism to optimize the biological and mechanical properties of the scaffold. The optimal COL1/HAp-loaded with hAMSCs were implanted into the tendon-bone rotator cuff interfaces in rats and the effect on the tendon-bone healing was assessed by micro-CT, histological analysis, and biomechanical properties. The results showed that Genipin and EDC/NHS dual cross-linked COL1/HAp had good biological activity and mechanical properties and promoted the proliferation and differentiation of hAMSCs. Animal experiments showed that the group using a scaffold loaded with hAMSCs had excellent continuity and orientation of collagen fibers, increased fibrocartilage and bone formation, and significantly higher biomechanical functions than the control group at the interface at 12 weeks post operation. This study demonstrated that dual cross-linked gradient COL1/HAp-loaded hAMSCs could promote interface healing, thereby providing a feasible strategy for tendon-bone interface regeneration.

The dynamics of bioactive compounds and their contributions to the antioxidant activity of postharvest chive (Allium schoenoprasum L.).

Organosulfur compounds, phenolic compounds, and ascorbic acids (AsA) are known to account for the bulk of chive's (Allium schoenoprasum L.) antioxidant properties. This study uncovered the contribution of each of these compounds to the chive's antioxidant activity under different storage conditions. The results showed that room temperature (RT) accelerated the accumulation of reactive oxygen species, though phenolics, organosulfur compounds, activities of antioxidant enzymes, and scavenging activity toward hydroxyl radical (OH) and superoxide anion (O2-) were observed to be enhanced in chives stored at RT. In contrast, AsA content, DPPH (1,1-diphenyl-1-picrylhydrazyl) scavenging and FRAP (ferric reducing antioxidant power) activity of the chive were increased by LT on day 5. Furthermore, S-alk(en)ylcysteine sulfoxides (CSOs) showed OH scavenging and weak DPPH scavenging but had no O2- scavenging and FRAP capacity. Volatile organosulfur compounds showed no antioxidant activities. Conclusively, the data demonstrated that AsA was largely responsible for DPPH scavenging and FRAP activity of the chive, while phenolic compounds, especially vanillic acid and p-hydroxybenzoic acid, were primarily responsible for OH and O2- scavenging activity.

Development and Validation of a Predictive Model for Chronic Postsurgical Pain After Arthroscopic Rotator Cuff Repair: A Prospective Cohort Study.

Purpose: Chronic pain management continues to present a significant challenge following arthroscopic shoulder surgery. Our purpose was to detect chronic postsurgical pain (CPSP) in patients who had undergone arthroscopic rotator cuff repair (ARCR) and develop a nomogram capable of predicting the associated risk. Patients and Methods: We collected the demographic and clinical data of 240 patients undergoing ARCR in our hospital from January 2021 to May 2022. The pain level was monitored and evaluated three months after ARCR. LASSO regression was used to screen out pain-predicting factors, which were subsequently used to construct a nomogram. Internal validation was carried out using Bootstrap resampling. The data of 78 patients who underwent ARCR in our hospital from August 2022 to December 2022 were also collected for external verification of the nomogram. The predictive model was evaluated using the receiver operating characteristic curve (ROC), calibration curve, and decision curve analysis (DCA). Results: Age, duration of preoperative shoulder pain (DPSP), C-reactive protein (CRP), number of tear tendons, and American Shoulder and Elbow Surgical Score (ASES) were screened by LASSO regression as predictive factors for CPSP. These factors were then used to construct a chronic pain risk nomogram. The area under the curve (AUC) of the predictive and validation models were 0.756 (95% CI: 0.6386-0.8731) and 0.806 (95% CI: 0.6825-0.9291), respectively. Furthermore, the calibration curves and decision curve analysis (DCA) for both models indicated strong performance, affirming the reliability of this predictive model. Conclusion: The CPSP risk model that has been developed exhibits strong predictive capabilities and practical utility. It offers valuable support to clinical healthcare professionals in making informed treatment decisions, reducing the unnecessary use of analgesic drugs, and optimizing the allocation of medical resources.

Sintilimab treatment for chronic active Epstein-Barr virus infection and Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis in children.

BACKGROUND: Chronic active Epstein-Barr virus infection (CAEBV) and Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH) are rare but life-threatening progressive diseases triggered by EBV infection. Glucocorticoid/immunosuppressants treatment is temporarily effective; however, most patients relapse and/or progress. Hematopoietic stem cell transplantation (HSCT) is a potentially curative therapy; however, there are risks of transplantation-associated complications. Currently there is no standard treatment for CAEBV and EBV-HLH. Programmed death protein 1 (PD-1) inhibitors have achieved a high response in many EBV-related diseases. Sintilimab (a recombinant human IgG4 monoclonal antibody against PD-1) disrupts the interaction between PD-1 and its ligand, leading to T cell reinvigoration. METHODS: A retrospective analysis was performed on three children with CAEBV or EBV-HLH in the Children's Hospital of Soochow University between 12 December 2020 and 28 November 2022. The efficacy of sintilimab was evaluated. RESULTS: Three patients, including two males and one female, were analyzed. Among them, two children were diagnosed with CAEBV with intermittent fever for more than four years, and one child was diagnosed with EBV-HLH. After sintilimab treatment and a mean follow-up of 17.1 months (range 10.0-23.3 months), patients 1 and 3 achieved a complete clinical response and patient 2 achieved a partial clinical response. All three children showed a > 50% decrease in EBV-DNA load in both blood and plasma. EBV-DNA copies in sorted T, B, and NK cells were also markedly decreased after sintilimab treatment. CONCLUSION: Our data supported the efficacy of PD-1 targeted therapy in certain patients with CAEBV and EBV-HLH, and suggested that sintilimab could provide a cure for these diseases, without HSCT. More prospective studies and longer follow-up are needed to confirm these conclusions.

Clinical features and management of atypical hemolytic uremic syndrome patient with DGKE gene variants: a case report.

Background: Atypical hemolytic uremic syndrome (aHUS) with diacylglycerol kinase epsilon (DGKE) gene variant is a rare variant of thrombotic microangiopathy (TMA). The information on the clinical features, management and long-term outcomes of DGKE-aHUS patients have not yet been fully elucidated. The aim of this study was to report a novel variant of the DGKE gene in a Chinese population with aHUS. Case presentation: The present work reports a 7-month-old boy with aHUS, possibly triggered by gastrointestinal infection, without complement activation, with little response to plasma therapy and nephroprotective measures. The patient died during the 8th week of his hospital stay. The causes of death were intracranial hemorrhage and multiorgan dysfunction. Comprehensive WES of peripheral blood-derived DNA revealed two heterozygous variations in the DGKE exon region: NM_003647.2, c.610dup, p.Thr204Asnfs*4 and deletion of exons 4-6. Conclusions: This case suggest that atypical HUS with DGKE gene variant has a poor prognosis with a high mortality rate, which typically manifests in the first year of life and presents as a systemic disease with early-onset HUS with rapidly worsening renal function and chronic proteinuria. There is no specific treatment for DGKE-aHUS. There have an uncertain benefit of plasma therapy for DGKE-aHUS patients. The literature demonstrated that anti-complement therapy showed benefits for DGKE-aHUS with complement activation and autoantibodies during the overt TMA presentation but did not prevent TMA relapses. Early diagnosis and treatment may prevent complications and improve prognosis.

The role of PD-1 signaling in health and immune-related diseases.

Programmed cell death 1 receptor (PD-1) and its ligands constitute an inhibitory pathway to mediate the mechanism of immune tolerance and provide immune homeostasis. Significantly, the binding partners of PD-1 and its associated ligands are diverse, which facilitates immunosuppression in cooperation with other immune checkpoint proteins. Accumulating evidence has demonstrated the important immunosuppressive role of the PD-1 axis in the tumor microenvironment and in autoimmune diseases. In addition, PD-1 blockades have been approved to treat various cancers, including solid tumors and hematological malignancies. Here, we provide a comprehensive review of the PD-1 pathway, focusing on the structure and expression of PD-1, programmed cell death 1 ligand 1 (PD-L1), and programmed cell death 1 ligand 2 (PD-L2); the diverse biological functions of PD-1 signaling in health and immune-related diseases (including tumor immunity, autoimmunity, infectious immunity, transplantation immunity, allergy and immune privilege); and immune-related adverse events related to PD-1 and PD-L1 inhibitors.

Nitrogen-phosphorous co-doped carbonized chitosan nanoparticles for chemotherapy and ROS-mediated immunotherapy of intracellular Staphylococcus aureus infection.

Staphylococcus aureus (S. aureus) residing in host macrophages is hard to clear because intracellular S. aureus has evolved mechanisms to hijack and subvert the immune response to favor intracellular infection. To overcome this challenge, nitrogen-phosphorous co-doped carbonized chitosan nanoparticles (NPCNs), which possess the polymer/carbon hybrid structures, were fabricated to clear intracellular S. aureus infection through chemotherapy and immunotherapy. Multi-heteroatom NPCNs were fabricated through the hydrothermal method, where chitosan and imidazole were used as the C and N sources and phosphoric acid as the P source. NPCNs can not only be used as a fluorescent probe for bacteria imaging but also kill extracellular and intracellular bacteria with low cytotoxicity. NPCNs could generate ROS and polarize macrophages into classically activated (M1) phenotypes to increase antibacterial immunity. Furthermore, NPCNs could accelerate intracellular S. aureus-infected wound healing in vivo. We envision that these carbonized chitosan nanoparticles may provide a new platform for clearing intracellular bacterial infection through chemotherapy and ROS-mediated immunotherapy.

Addition of platelet-lymphocyte ratio to risk factors to improve the early prediction of acute kidney injury and mortality in critically ill neonates.

BACKGROUND: To determine whether early neutrophil, lymphocyte, and platelet ratio (NLPR), neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR), calculated based on easily available parameters in complete blood count, are associated with the development of acute kidney injury (AKI) and mortality during neonatal intensive care unit (NICU) stay, and to evaluate whether these ratios could act as a predictor of AKI and mortality in neonates. METHODS: The pooled data of 442 critically ill neonates from our previously published prospective observational studies of urinary biomarkers were analyzed. Complete blood count (CBC) was measured on NICU admission. The clinical outcomes included AKI developed during the first 7 days after admission and NICU mortality. RESULTS: Of the neonates, 49 developed AKI and 35 died. The association of the PLR, but not NLPR and NLR, with AKI and mortality remained significant after adjustment for potential confounders including birth weight and illness severity as assessed by the score for neonatal acute physiology (SNAP). The area under the curve (AUC) of the PLR for predicting AKI and mortality was 0.62 (P=0.008) and 0.63 (P=0.010), respectively, with additional predictive value when combined with other perinatal risk factors. The combination of PLR with birth weight, SNAP, and serum creatinine (SCr) had an AUC of 0.78 (P<0.001) in predicting AKI, and its combination with birth weight and SNAP had an AUC of 0.79 (P<0.001) in predicting mortality. CONCLUSIONS: Low PLR on admission is associated with increased risk for AKI and NICU mortality. Although the PLR alone is not predictive of AKI and mortally, it adds predictive value to other risk factors for AKI prediction in critically ill neonates.

Bioactive Peptide-Mimicking Polymer Nanoparticles for Bacteria Imaging and Chemo/Immunotherapy of Intracellular Infection.

Intracellular bacterial infections are extremely difficult to be treated because intracellular bacteria have developed resistant mechanisms to escape the immune attack and antibiotic therapy. It remains challenging to develop antibiotic-free materials and relative strategies for treating intracellular bacterial infections. Herein, a new host-defense peptide-mimicking polymer nanoparticle, inspired by cell-penetrating peptides, was developed to eradicate intracellular bacteria by its outstanding antibacterial and pro-inflammatory immunomodulatory. The polymer nanoparticle (TPE-Parg) was prepared through ring-opening polymerization of N6-carbobenzoxy-l-lysine N-carboxyanhydride (Cbz-l-Lys NCA) using 1-(4-aminophenyl)-1,2,2-triphenylethene (TPE-NH2) as the initiator, followed by deprotection of the Cbz-l-Lys NCA group and guanidinium modification. The impact of cationic functional groups and chain length variation on the antibacterial activity of polymer nanoparticle were investigated in detail. The results confirmed that the optimal polymer nanoparticle could not only image bacteria with aggregation-induced blue fluorescence, but also kill planktonic bacteria with low cytotoxicity. Furthermore, the nanoparticle could induce macrophages to generate nitric oxide (NO) and activate the immune system to eliminate intracellular bacteria. The nanoparticle further showed its potent in vivo antibacterial activity in an intracellular Staphylococcus aureus infection model fabricated on mice hypodermic. The obtained multifunctional host-defense peptide-mimicking polymer nanoparticles with potent antibacterial activity (chemotherapy) and pro-inflammatory immunomodulatory (immunotherapy) are excellent alternatives for intracellular antibacterial therapy and provide a direction for developing innovative antimicrobials.

Pathological evaluation of renal complications in children following allogeneic hematopoietic stem cell transplantation: a retrospective cohort study.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative therapy for hematologic malignancies and non-malignant disorders, such as aplastic anemia, fanconi anemia, and certain immune deficiencies. Post-transplantation kidney injury is a common complication and involves a wide spectrum of structural abnormalities, including glomerular (MSPGN, mesangial proliferative glomerulonephritis; FSGS, focal segmental glomerulosclerosis; MPGN, membranoproliferative glomerulonephritis; MCD, minimal change disease), vascular (TMA, thrombotic microangiopathy), and/or tubulointerstitial (TIN, tubulointerstitial nephritis; ATI, acute tubular injury). Renal biopsy is the gold-standard examination for defining multiple etiologies of kidney impairment. Although kidney injury following HSCT has been studied, little is known about the effects of allo-HSCT on renal pathology in pediatric patients. METHODS: We retrospectively analyzed renal biopsy specimens from children with kidney injury after allo-HSCT and correlated results with clinical data in the last 10 years. RESULTS: Among 25 children (18 males and 7 females), three patients had proteinuria indicating nephrotic syndrome (24-hour urinary total protein/weight > 50 mg/kg/d), nine patients had severely reduced estimated glomerular filtration rate (eGFR < 30 ml/min/1.73 m2) and four patients received kidney replacement therapy (KRT). The main pathologies identified from kidney biopsies were MSPGN (n = 12), FSGS (n = 12), MPGN (n = 5), TMA (n = 4), MCD (n = 3), diffuse glomerular fibrosis (DGF, n = 2), ATI and TIN, in isolation or combined with other pathologies. The median follow-up time was 16.5 (0.5 ~ 68.0) months. Three patients died of recurrent malignancy and/or severe infection, one child developed to end-stage renal disease (ESRD), six patients (24%) had elevated serum creatinine (SCr > 100µmol/l) and nine patients (36%) still had proteinuria. CONCLUSIONS: This study evaluates histomorphologic findings from kidney biopsies of pediatric recipients following allo-HSCT. Detailed evaluation of renal biopsy samples is helpful to elucidate the nature of renal insult, and may potentially identify treatable disease processes.

ε-Polylysine-Based Macromolecules with Catalase-Like Activity to Accelerate Wound Healing by Clearing Bacteria and Attenuating Inflammatory Response.

Wound healing has remained a critical challenge due to its susceptibility to bacterial infection and the unique biological inflammatory response. Safe and effective therapeutics are still lacking. Biodegradable macromolecules (ε-polylysine-g-ferrocene, EPL-g-Fc) were developed to accelerate wound healing by combating bacterial infection and attenuating inflammatory responses. The biodegradable macromolecules were prepared via a Schiff-based reaction between ferrocene carboxaldehyde (Fc) and ε-polylysine (EPL). Through the synergistic combination of positive-charged EPL and π-π stacked Fc, the macromolecules possess excellent antibacterial activities. EPL-g-Fc with catalase-like activity could modulate the oxidative microenvironment in mammalian cells and zebrafish by catalyzing H2O2 into H2O and O2. EPL-g-Fc could alleviate inflammatory response in vitro. Furthermore, the macromolecules could accelerate bacteria-infected wound healing in vivo. This work provides a versatile strategy for repairing bacteria-infected wounds by eliminating bacteria, modulating oxidative microenvironment, and alleviating inflammatory response.

Efficacy and safety of etanercept biosimilar rhTNFR-Fc in Chinese patients with juvenile idiopathic arthritis: An open-label multicenter observational study.

Background: Etanercept biosimilar recombinant human TNF-α receptor II: IgG Fc fusion protein (rhTNFR-Fc) has showed its efficacy and safety in Chinese patients with rheumatoid arthritis. However, data on rhTNFR-Fc's application in juvenile idiopathic arthritis (JIA) is limited. Methods: A prospective, observational, multicenter study was performed at 6 institutes in China from July 2020 to December 2021. In a 24-week follow-up, patients with JIA including polyarticular JIA and enthesitis related arthritis received rhTNFR-Fc plus methotrexate (MTX) treatment. The primary outcome parameters were improvements of cJADAS-10 (clinical Juvenile Arthritis Disease Activity Score), and the secondary outcome parameter was an inactive disease. Results: 60 patients completed at least 12-week follow-up, and 57 completed 24-week follow-up. They had high C reactive protein values (11.6 mg/L) and cJADAS-10 (14.6) at baseline. Thirteen patients had morning stiffness. 33 patients showed synovial thickening, and 34 showed bone marrow edemas on MRI. Ultrasonography demonstrated significant joint effusions in 43 patients. The cJADAS-10 sharply decreased from 14.66 at the baseline to 2.4 at 24 weeks of rhTNFR-Fc therapy, respectively (P < 0.01). About half of patients achieved inactive disease at 24 weeks of therapy. Compared with the baseline, the number of patients with morning stiffness, joint effusions, bone marrow edema and synovial thickening on MRI significantly decreased at 24 weeks. Adverse events were consistent with known side effects of biologic agents. Conclusions: The present study indicated that the combination of rhTNFR-Fc and MTX significantly improve symptoms and disease activity of children with JIA. This study suggests etanercept biosimilar rhTNFR-Fc as an effective and safe therapy for children with JIA.

pH-Responsive non-antibiotic polymer prodrugs eradicate intracellular infection by killing bacteria and regulating immune response.

Intracellular bacterial infections pose enormous challenges to food safety and public health. Antibiotic-based polymer prodrugs have been used to treat intracellular bacterial infection. However, the overuse of antibiotics may lead to the emergence of antibiotic resistance. In this work, we aimed to develop antibiotic-free pH-responsive polymeric prodrugs to combat intracellular S. aureus infection. Amphiphilic poly(ethylene glycol)-b-poly[(3-phenylprop-2-ene-1,1-diyl)bis(oxy)bis(enthane-2,1- diyl)diacrylate] (PEG-b-PCAE) was obtained by radical polymerization and they could self-assemble to form micelles. PEG-b-PCAE micelles could uptake by macrophage. Upon exposure to the acidic phagolysosome, PEG-b-PCAE micelles could release cinnamaldehyde (CA) through hydrolysis of the acetal linkage. PEG-b-PCAE could kill intracellular bacteria by damaging the bacterial membrane. Furthermore, PEG-b-PCAE micelles could generate reactive oxygen species (ROS) in macrophages and subsequently activate immune system to clear bacteria by inducing macrophages differentiation to M1 phenotype. PEG-b-PCAE micelles could accelerate the wound healing process of the S. aureus-infected model in vivo. It is anticipated that multifunctional antibiotic-free PEG-b-PCAE micelles with intrinsic antibacterial activities hold promise for improved outcomes in intracellular S. aureus infections.

pH-Responsive Hyperbranched Polymer Nanoparticles to Combat Intracellular Infection by Disrupting Bacterial Wall and Regulating Macrophage Polarization.

Intracellular bacterial infections pose a serious threat to public health. Macrophages are a heterogeneous population of immune cells that play a vital role in intracellular bacterial infection. However, bacteria that survive inside macrophages could subvert the cell signaling and eventually reduce the antimicrobial activity of macrophages. Herein, dual pH-responsive polymer (poly[(3-phenylprop-2-ene-1,1-diyl)bis(oxy)bis(enthane-2,1-diyl)diacrylate-co-N-aminoethylpiperazine] (PCA)) nanoparticles were developed to clear intracellular bacteria by activating macrophages and destructing bacterial walls. The presence of acid-labile acetal linkages and tertiary amine groups in the polymer's backbone endow hyperbranched PCA dual pH-response activity that shows acid-induced positive charge increase and cinnamaldehyde release properties. The biodegraded PCA nanoparticles could significantly inhibit the growth of bacteria by damaging the bacterial walls. Meanwhile, PCA nanoparticles could uptake by macrophages, generate reactive oxygen species (ROS), and remodel the immune response by upregulating M1 polarization, leading to the reinforced antimicrobial capacity. Furthermore, PCA nanoparticles could promote bacteria-infected wound healing in vivo. Therefore, these dual pH-responsive PCA nanoparticles enabling bacteria-killing and macrophage activation provide a novel outlook for treating intracellular infection.

Transcriptome analysis reveals the genes involved in S-alk(en)ylcysteine sulfoxide biosynthesis and its biosynthetic location in postharvest chive (Allium schoenoprasum L.).

The biosynthetic mechanism of S-alk(en)ylcysteine sulfoxides (CSOs), a flavor precursor and nonvolatile medicinal compound in chive is still poorly understood. In the present study, transcriptomic analysis was used to investigate the biosynthetic mechanism of S-alk(en)ylcysteine sulfoxides (CSOs) in green leaves of postharvest chive stored under normal temperature (20 °C) for 5 d and low-temperature (3 °C) for 12 d. The de novo assembly of the transcriptome enabled the identification of unigenes involved in the sulfur assimilation and CSOs biosynthesis. The RNA-seq data showed that the unigenes related to sulfur assimilation were down-regulated during storage under 20 °C and 3 °C. The low temperature did not affect cysteine biosynthesis and the expression of γ-glutamyl transpeptidase (GGT) and flavin-containing monooxygenase (FMO) involved in CSOs biosynthesis; nonetheless, it prolonged CSOs synthesis by sustaining the chive quality during the storage period. The qPCR data revealed that the expressions of genes related to sulfur assimilation were mainly in the white stalk. In contrast, CSOs biosynthetic genes had higher expression levels in green leaf. The results indicate the CSOs were mainly synthesized in green leaf while cysteine, the primary substrate for CSOs synthesis, was from de novo synthesis and proteolysis. The study presents discrete evidence that CSOs biosynthesis in postharvest chives occurs in green leaves and is translocated to the white stalk for storage.

Derivation and validation of urinary TIMP-1 for the prediction of acute kidney injury and mortality in critically ill children.

BACKGROUND: Acute kidney injury (AKI) is associated with high morbidity and mortality. Multiple urinary biomarkers have been identified to be associated with the prediction of AKI and outcomes. However, the accuracy of these urinary biomarkers for AKI and associated outcomes has not been clearly defined, especially in heterogeneous populations. The aims of the study were to compare the ability of 10 existing or potential urinary biomarkers to predict AKI and pediatric intensive care unit (PICU) mortality and validate urinary tissue inhibitor of metalloproteinases-1 (uTIMP-1) as a better biomarker for early prediction in heterogeneous critically ill children. METHODS: A derivation-validation approach with separate critically ill cohorts was designed. We first conducted a prospective cohort study to determine the ability of 10 urinary biomarkers serially measured in 123 children during the first 7 days of PICU stay to predict AKI and PICU mortality (derivation study) and further validated the better biomarker of uTIMP-1 in a separate cohort of 357 critically ill children (validation study). AKI diagnosis was based on KDIGO classification with serum creatinine and urine output. PICU mortality was defined as all-cause mortality. RESULTS: In the derivation cohort, 17 of 123 (13.8%) children developed AKI stage 3 or died during the PICU stay, and both the initial and peak uTIMP-1 displayed the highest AUCs of 0.87 (0.79-0.94) and 0.90 (0.84-0.96), respectively, for predicting AKI stage 3 or death. In the validation cohort, 78 of 357 (21.8%) developed AKI during the first week after admission, and 38 (10.6%) died during the PICU stay. The initial uTIMP-1 level was validated to be independently associated with AKI (AOR = 2.88, 95% CI 1.97-4.21), severe AKI (AOR = 2.62, 95% CI 1.78-3.88), AKI stage 3 (AOR = 2.94, 95% CI 1.84-4.68) and PICU mortality (AOR = 1.92, 95% CI 1.11-3.30) after adjustment for potential confounders. The predictive values of uTIMP-1 for AKI, severe AKI, AKI stage 3 and PICU mortality were 0.80 (0.74-0.86), 0.83 (0.77-0.89), 0.84 (0.77-0.92) and 0.83 (0.76-0.89), respectively. CONCLUSIONS: Urinary TIMP-1 levels have been identified and validated to be independently associated with AKI and PICU mortality in independent prospective cohorts and may be an early potential indicator of AKI and PICU mortality in critically ill children.

pH-Responsive Fluorescent Polymer-Drug System for Real-Time Detection and In Situ Eradication of Bacterial Biofilms.

Bacterial biofilms encased in extracellular polymeric substances to create protected microenvironments are typically challenging to disperse by common antibiotics and cannot be in situ visualized under current modalities. Herein, a pH-responsive branched polymer [poly(MBA-AEPZ)-AEPZ-NA] capable of overcoming antibiotic resistance and real-time visualizing biofilms for fluorescence imaging-guided infection control is reported. The positively charged polymer can effectively penetrate bacterial biofilms, neutralize the anionic character, and then disrupt the structural integrity, thus significantly promoting the transport of antibiotics into biofilms. The polymer shows a weak fluorescence emission intensity under physiological conditions (pH 7.4) but emits intense green-light emission within the localized biofilm microenvironment (pH 5.5) to real-time visualize bacterial biofilms. A therapeutic system made of the polymer and a model antibiotic can significantly reduce the dosages of the drug, thereby minimizing biofilm-induced drug resistance. Notably, a green fluorescent polymer responding to localized pH conditions is demonstrated in living zebrafish. This work confirmed that combinations of the pH-responsive branched polymer and antibiotics could be administered to overcome drug resistance and realize fluorescence imaging-guided treatment of bacterial biofilm infections.