A single-chain fab derived drug conjugate for HER2 specific delivery.

Despite the development of antibody-drug conjugates, the fragment Fab-based drug conjugates offer some unique capabilities in terms of safety, clearance, penetration and others. Current methods for preparing Fab drug conjugates are limited by the availability and stability of Fab proteins, leaving reports on this rare. Here, we found that a single-chain scaffold of Fab enables stabilization of the paired structure and supports high-yield expression in bacteria cytoplasm. Furthermore, we conjugated anti-neoplastic agent SN38 to the C-terminus by sortase A ligation and generated a homogenous Fab conjugate with the drug-to-Fab ratio of 1. The resulting anti-HER2 Fab-SN38 conjugate demonstrated potent and antigen-dependent cell-killing ability with the aid of its special cathepsin-triggered cyclization-promoted release mechanism. In vivo, Fab-SN38 can prevent growths of HER2-positive tumors in athymic mice and be well tolerated to the treatment at 7 mg/kg per dose. Anti-tumor activity, high dose tolerance and penetration advantage observed in this study would merit Fab conjugate investigation in target chemotherapy.

Appendicitis after endoscopic band ligation for massive ileocecal hemorrhage.

A 68-year-old man was admitted with hematochezia. Emergency computed tomography showed multiple diverticula throughout the colon. Initial colonoscopy on day 2 showed no active bleeding, but massive hematochezia on day 3 led to the performance of an emergency endoscopy. Substantial bleeding in the ileocecal area obscured the visual field, making it challenging to view the area around the bleeding site. Two endoscopic band ligations (EBLs) were applied at the suspected bleeding sites. Hemostasis was achieved without active bleeding after EBL. However, the patient developed lower right abdominal pain and fever (39.4°C) on day 6. Urgent computed tomography revealed appendiceal inflammation, necessitating emergency open ileocecal resection for acute appendicitis. Pathological examination confirmed acute phlegmonous appendicitis, with EBLs noted at the appendiceal orifice and on the anal side. This case illustrates the efficacy of EBL in managing colonic diverticular bleeding. However, it also highlights the risk of appendicitis due to EBL in cases of ileocecal hemorrhage exacerbated by poor visibility due to substantial bleeding. Endoscopists need to consider this rare but important complication when performing EBL in similar situations.

Application of Sortase-Mediated Ligation for the Synthesis of Block Copolymers and Protein-Polymer Conjugates.

Sortase-mediated ligation (SML) has become a powerful tool for site-specific protein modification. However, sortase A (SrtA) suffers from low catalytic efficiency and mediates an equilibrium reaction. Therefore, ligations with large macromolecules may be challenging. Here, the synthesis of polymeric building blocks for sortase-mediated ligation constituting peptide-polymers with either the recognition sequence for sortase A (LPX1TGX2) or its nucleophilic counterpart (Gx) is demonstrated. The peptide-polymers are synthesized by solid-phase peptide synthesis followed by photo-iniferter (PI) reversible addition-fragmentation chain-transfer (RAFT) polymerization of various monomers. The building blocks are subsequently utilized to investigate possibilities and limitations when using macromolecules in SML. In particular, diblock copolymers are obtained even when using the orthogonal building blocks in equimolar ratio by exploiting a technique to shift the reaction equilibrium. However, ligations of two polymers can not be achieved when the degree of polymerization exceeds 100. Subsequently, C-terminal protein-polymer conjugates are synthesized. Several polymers are utilized that can replace the omnipresent polyethylene glycol (PEG) in future therapeutics. The conjugation is exemplified with a nanobody that is known for efficient neutralization of SARS-CoV-2. The study demonstrates a universal approach to polymer-LPX1TGX2 and Gx-polymer building blocks and gives insight into their application in SML.

Redefining hemorrhoid therapy with endoscopic polidocanol foam sclerobanding.

Hemorrhoids are a common and painful condition, with conventional treatments such as endoscopic rubber band ligation (ERBL) and injection sclerotherapy often falling short due to high recurrence rates and significant post-operative pain. A clinical trial by Qu et al introduces a novel approach called endoscopic poli-docanol foam sclerobanding (EFSB). This multicenter randomized trial involved 195 patients with grade II and III internal hemorrhoids and demonstrated that EFSB significantly reduced recurrence rates and post-procedural pain while improving symptom relief and patient satisfaction compared to ERBL. The study's strengths include its robust design, comprehensive outcome evaluation, and patient-centered approach. Despite limitations such as the single-blind design and relatively short follow-up period, the findings suggest that EFSB could enhance clinical practice by offering a more effective and patient-friendly treatment option. Further research is needed to validate these results and explore the long-term benefits and cost-effectiveness of EFSB.

Clinical evaluation of CoolSeal - a new, safe, and fast vessel sealing device in total thyroidectomy.

Objective. CoolSeal is a new vessel sealing system for dissection and hemostasis during surgery. No clinical studies have investigated safety, advantages or disadvantages regarding the use of this device. The aim of the present study was to investigate the safety of CoolSeal and compare it with conventional ligation technique or LigaSure during the total thyroidectomy. We hypothesized that the use of CoolSeal would reduce the operating time and bleeding without complications increase. Study design represents a retrospective cohort study with a tertiary reference center setting. Methods. We analyzed total thyroidectomy data from January 2021 to June 2023. We recorded patients' characteristics, surgical information, and postoperative outcome. Results. We performed 221 total thyroidectomies in the study period. Analysis was restricted to 171 patients operated by only two surgeons. Hemostasis was secured by conventional ligation in 117 patients (68%), LigaSure in 34 patients (20%) and CoolSeal in 20 patients (12%). Median thyroid weight and bleeding were 67 g and 50 ml, respectively. Procedures using LigaSure or Cool-Seal were on larger glands (median 205 g) without increased bleeding (50 ml). Operating time was shortest with CoolSeal (96 min, p=0.003) compared with LigaSure (117 min) or conventional ligation (115 min). Bleeding was reduced with CoolSeal compared with LigaSure (45 vs. 100 ml, p=0.003). With CoolSeal, median hospitalization was one postoperative day, no patients required re-operation. There was no palsy of recurrent laryngeal nerves and no permanent hypoparathyroidism. Conclusion. In our first clinical experience, CoolSeal was safe and efficient for total thyroidectomy. With a small sample size, we saw a clinical benefit with reduced operating time without post-operative complications increase.

Hepatoprotective effects of vildagliptin mitigates lung biochemical and histopathological changes in experimental hepatopulmonary syndrome model in rat.

Hepatopulmonary syndrome (HPS) is a liver disease-induced pulmonary complication manifested with arterial hypoxemia. Hepatic cholestasis, encountered in several clinical situations, leads to biliary cirrhosis and HPS, both of which are best reproduced by rat common bile duct ligation (CBDL). Experience from liver transplantation suggests hepatoprotective-based therapy would be most effective in HPS treatment Dipeptidyl peptidase-4 (DPP-4) enzyme is involved in different pathogenic mechanisms of liver diseases. Vildagliptin (Vild) is a DPP-4 inhibitor which possesses favorable anti-inflammatory, anti-oxidant and anti-fibrotic effects. The present work explored hepatoprotective mechanisms of Vild and their participation in its prophylactic effectiveness in HPS induced by CBDL in rats. Male Wistar rats weighing 220-280 g were allocated into 4 groups: normal control, sham, CBDL and CBDL + Vild groups. i.p. saline was administered to the first 3 groups and i.p. Vild (10 mg/kg/day) was given to the fourth group for 6 weeks starting 2 week before CBDL. CBDL produced liver fibrosis, arterial hypoxemia and decreased survivability of rats. It altered liver functions and induced oxidative stress, pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6)], vasodilatory molecules [endothelin-1 (ET-1), and inducible and endothelial nitric oxide synthases] and angiogenesis-associated protein [vascular endothelial growth factor-A (VEGF-A)] in liver and lung. Vild ameliorated liver fibrosis, and improved hypoxemia and survivability of CBDL rats and reversed these biochemical alterations. Prophylactic Vild administration attenuated CBDL-induced HPS in rats via direct hepatoprotective effects in the form of anti-oxidant, anti-inflammatory, anti-angiogenic and anti-fibrotic effects beside inhibition of pathological intrahepatic vasodilatation.

Adnexal Torsion During Pregnancy in a Surrogate Patient Post-tubal Ligation: A Case Report.

Adnexal torsion during pregnancy is rare and is complicated by ambiguous symptoms and often nonspecific imaging findings. Differential diagnoses of torsion include a ruptured ovarian cyst, tubo-ovarian abscess, and appendicitis. A low threshold for the recommended surgical laparoscopy is necessary to avoid delayed diagnosis and fetal or maternal complications. We present a case of a 30-year-old woman at 10 weeks gestation as a surrogate carrier, admitted for progressive, sharp lower right quadrant abdominal pain. On presentation, she was afebrile and vitally stable, with moderate leukocytosis and elevated inflammatory markers. Transvaginal ultrasound showed a 6 x 6 cm adnexal mass/cyst, without ovarian vascular compromise, in addition to a tubular structure indicating possible hydrosalpinx. Initially, her presenting symptoms partially resolved following antibiotics and analgesics, which led us to consider a tubo-ovarian abscess as the culprit. However, upon a recurrence of pain, we proceeded with a diagnostic laparoscopy, with a high suspicion of ovarian torsion. A right adnexal torsion and paratubal cyst were identified; detorsion with preservation of adnexa and cystectomy was performed, with resolution of the pain in the postoperative period. This case underscores the importance of identifying multiple risk factors and complex clinical scenarios for ovarian torsion in premenopausal patients in the context of surrogate pregnancies following tubal ligation. Our findings contribute to the existing literature by emphasizing the need for a high index of suspicion for adnexal torsion, as it is imperative to prevent complications and ensure prompt surgical intervention.

Neuromolecular and behavioral effects of cannabidiol on depressive-associated behaviors and neuropathic pain conditions in mice.

BACKGROUND AND AIMS: Neuropathic pain (NP) has a high incidence in the general population, is closely related to anxiety disorders, and has a negative impact on the quality of life. Cannabidiol (CBD), as a natural product, has been extensively studied for its potential therapeutic effects on symptoms such as pain and depression (DP). However, the mechanism of CBD in improving NP with depression is not fully understood. METHODS: First, we used bioinformatics tools to deeply mine the intersection genes associated with NP, DP, and CBD. Secondly, the core targets were screened by Protein-protein interaction network, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes analysis, molecular docking and molecular dynamics simulation. Next, the effects of CBD intervention on pain and depressive behaviors in the spinal nerve ligation (SNL) mouse model were evaluated using behavioral tests, and dose-response curves were plotted. After the optimal intervention dose was determined, the core targets were verified by Western blot (WB) and Quantitative Polymerase Chain Reaction (qPCR). Finally, we investigated the potential mechanism of CBD by Nissl staining, Immunofluorescence (IF) and Transmission Electron Microscopy (TEM). RESULTS: A total of five core genes of CBD most associated with NP and DP were screened by bioinformatics analysis, including PTGS2, GPR55, SOD1, CYP1A2 and NQO1. Behavioral test results showed that CBD by intraperitoneal administration 5 mg/kg can significantly improve the pain behavior and depressive state of SNL mice. WB, qPCR, IF, and TEM experiments further confirmed the regulatory effects of CBD on key molecules. CONCLUSION: In this study, we found five targets of CBD in the treatment of NP with DP. These findings provide further theoretical and experimental basis for CBD as a potential therapeutic agent.

Small Molecule Detection with Ligation-Dependent Light-Up Aptamer Transcriptional Amplification.

ATP and NAD+ are small biomolecules that participate in a variety of physiological functions and are considered as potential biomarkers for disease diagnosis. In this study, we developed a ligation-dependent light-up aptamer transcriptional amplification assay for the sensitive and selective detection of ATP and NAD+. This assay relies on a specific DNA ligase that catalyzes the ligation of a nicked DNA template in the presence of a specific small molecule. We prepared a nicked template consisting of a duplex fragment with an overhang for the T7 promoter region and a single-stranded DNA with a complementary overhang sequence for the Broccoli aptamer. The nicked template was connected using a DNA ligase in the presence of a specific small molecule. The ligation product was subjected to in vitro transcription to amplify the light-up aptamer-mediated fluorescence signals. By integrating the target-dependent ligation and transcription amplification, significant signal amplification was achieved with 5.9 and 142 pM detection limits for ATP and NAD+, respectively. Moreover, good selectivity to discriminate between the target and its analogues was also realized. The application of this method to biological samples was evaluated using human serum and exhibited excellent recovery values.

Improved method for detecting protein-protein interactions using proximity ligation assay.

Proximity ligation assay has been widely used to detect protein-protein interaction in cells and tissues. While with great sensitivity, its specificity was often neglected. Here, we report the existence of varying levels of false positives observed with this assay and provide suggestions to minimize false positives for more accurate detection of protein-protein interactions, especially for membrane proteins.

BracketMaker: Visualization and optimization of chemical protein synthesis.

Chemical protein synthesis (CPS), in which custom peptide segments of ~20-60 aa are produced by solid-phase peptide synthesis and then stitched together through sequential ligation reactions, is an increasingly popular technique. The workflow of CPS is often depicted with a "bracket" style diagram detailing the starting segments and the order of all ligation, desulfurization, and/or deprotection steps to obtain the product protein. Brackets are invaluable tools for comparing multiple possible synthetic approaches and serve as blueprints throughout a synthesis. Drawing CPS brackets by hand or in standard graphics software, however, is a painstaking and error-prone process. Furthermore, the CPS field lacks a standard bracket format, making side-by-side comparisons difficult. To address these problems, we developed BracketMaker, an open-source Python program with built-in graphic user interface (GUI) for the rapid creation and analysis of CPS brackets. BracketMaker contains a custom graphics engine which converts a text string (a protein sequence annotated with reaction steps, introduced herein as a standardized format for brackets) into a high-quality vector or PNG image. To aid with new syntheses, BracketMaker's "AutoBracket" tool automatically performs retrosynthetic analysis on a set of segments to draft and rank all possible ligation orders using standard native chemical ligation, protection, and desulfurization techniques. AutoBracket, in conjunction with an improved version of our previously reported Automated Ligator (Aligator) program, provides a pipeline to rapidly develop synthesis plans for a given protein sequence. We demonstrate the application of both programs to develop a blueprint for 65 proteins of the minimal Escherichia coli ribosome.

Echinatin alleviates sepsis severity through modulation of the NF-κB and MEK/ERK signaling pathways.

Sepsis, a frequently fatal condition, emerges from an exaggerated inflammatory response to infection, resulting in multi-organ dysfunction and alarmingly high mortality rates. Despite the urgent need for effective treatments, current therapeutic options remain limited to antibiotics, with no other efficacious alternatives available. Echinatin (Ecn), a potent bioactive compound extracted from the roots and rhizomes of licorice, has gained significant attention for its broad pharmacological properties, particularly its ability to combat oxidative stress. Recent research highlights the crucial role that oxidative stress plays in the onset and progression of sepsis further emphasizing the potential therapeutic value of Ecn in this context. In this study, we explored the protective effects of Ecn in a murine model of sepsis induced by cecal ligation and puncture (CLP). Ecn demonstrated a significant reduction in the levels of inflammatory cytokines and reactive oxygen species (ROS) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Network pharmacology analysis identified 41 targets and top 15 pathways involved in the Ecn-mediated signaling network, revealing that Ecn might exert its effects through key targets including the NF-κB and MAPK signaling pathways. Molecular docking studies suggested a strong affinity between Ecn and MEK, with kinetic simulations and binding energy calculations confirming a stable interaction. Mechanistically, Ecn treatment inhibited NF-κB and the MEK/ERK signaling pathway, as evidenced by decreased phosphorylation of IκBα and nuclear p65, along with reduced phosphorylation of MEK and ERK in both LPS-stimulated RAW 264.7 macrophages and septic mice. Furthermore, the administration of MEK signaling agonists reversed the anti-inflammatory effects of Ecn, indicating the involvement of this signaling pathway in Ecn's protective mechanism. Notably, our investigation revealed that Ecn did not affect bacterial proliferation either in vivo or in vitro, underscoring its specific immunomodulatory effects rather than direct antimicrobial activity. In summation, our findings underscored the potential of Ecn as an innovative therapeutic remedy for sepsis-induced injury, particularly through the regulation of the NF-κB and MEK/ERK signaling pathway. This exploration unveiled a promising therapeutic approach for treating sepsis, supplementing existing interventions and addressing their constraints.

Efficacy of associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) in hepatocellular carcinoma with macrovascular invasion: a single-center retrospective analysis.

Objective The influence of macrovascular invasion on the therapeutic efficacy of Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy (ALPPS) in hepatocellular carcinoma (HCC) patients has not been previously reported. This study primarily examines the therapeutic effect of ALPPS in treating HCC with macrovascular invasion. Methods 89 patients who underwent ALPPS at the First Affiliated Hospital of Guangxi Medical University from December 2016 to December 2021 were included. Patients were categorized into three groups based on macrovascular invasion status: pure HCC, HCC with portal vein tumor thrombus (PVTT), and HCC with hepatic vein tumor thrombus (HVTT). Outcome measures such as postoperative complications, liver hyperplasia rates, and survival times were compared across the groups. Results The study comprised 44 patients without macrovascular invasion and 45 cases with it, including 37 PVTT and 8 HVTT cases. Patients with PVTT or HVTT had a higher rate of complications and liver failure after the first ALPPS stage compared to those without macrovascular invasion (P = 0.018, P = 0.036). This trend was also observed in the stratified analysis of severe complications. However, no significant differences were found in these outcomes after the second ALPPS stage among the groups. The volume and rate of future liver remnant proliferation between the two stages of ALPPS were not statistically different among the groups, with median overall survival times of 42, 39, and 33 months, and progression-free survival times of 30, 24, and 14 months, respectively (P = 0.412 and P = 0.281). Conclusion ALPPS for HCC with macrovascular invasion was considered safe, feasible, and effective, as it achieved therapeutic effects comparable to those in cases without macrovascular invasion.

Evaluating the clinical efficacy of a long-read sequencing-based approach for carrier screening of spinal muscular atrophy.

Spinal muscular atrophy (SMA) is the second most common fatal genetic disease in infancy. It is caused by deletion or intragenic pathogenic variants of the causative gene SMN1, which degenerates anterior horn motor neurons and leads to progressive myasthenia and muscle atrophy. Early treatment improves motor function and prognosis in patients with SMA, but drugs are expensive and do not cure the disease. Therefore, carrier screening seems to be the most effective way to prevent SMA birth defects. In this study, we genetically analyzed 1400 samples using multiplex ligation-dependent probe amplification (MLPA) and quantitative polymerase chain reaction (qPCR), and compared the consistency of the results. We randomly selected 44 samples with consistent MLPA and qPCR results for comprehensive SMA analysis (CASMA) using a long-read sequencing (LRS)-based approach. CASMA results showed 100% consistency, visually and intuitively explained the inconsistency between exons 7 and 8 copy numbers detected by MLPA in 13 samples. A total of 16 samples showed inconsistent MLPA and qPCR results for SMN1 exon 7. CASMA was performed on all samples and the results were consistent with those of resampling for MLPA and qPCR detection. CASMA also detected an additional intragenic variant c.-39A>G in a sample with two copies of SMN1 (RT02). Finally, we detected 23 SMA carriers, with an estimated carrier rate of 1/61 in this cohort. In addition, CASMA identified the "2 + 0" carrier status of SMN1 and SMN2 in a family by analyzing the genotypes of only three samples (parents and one sibling). CASMA has great advantages over MLPA and qPCR assays, and could become a powerful technical support for large-scale screening of SMA.

Evidence-based surgery for cesarean hysterectomy secondary to placenta accreta spectrum: A systematic review.

OBJECTIVE: In this systematic review, we aim to propose evidence-based management for perioperative care to improve outcomes at the time of planned cesarean hysterectomy for placenta accreta spectrum, a procedure associated with significant maternal and neonatal morbidity. DATA SOURCES: We conducted a literature search for studies published in MEDLINE (via Ovid), Embase, CINAHL, and Cochrane/CENTRAL up until February 25, 2022. The search included free-text and controlled-vocabulary terms for cesarean section, cesarean delivery, and hysterectomy. STUDY ELIGIBILITY CRITERIA: We included randomized controlled trials, prospective cohort, retrospective cohort, and case-control studies published in English that reported on a perioperative intervention in the performance of a planned CH for PAS. Studies must have included a comparator group. Of the 8,907 studies screened in this systematic review, 79 met the inclusion criteria. STUDY APPRAISAL AND SYNTHESIS METHODS: Articles examining each step or intervention of the CH were grouped together and reviewed qualitatively as a group. Evidence levels and recommendations were made by consensus of all authors according to the terminology of the United States Preventive Services Task Force (USPSTF). We synthesized the results of 79 articles, and provided 28 recommendations. RESULTS: Based on USPSTF criteria, 21.4 % of the recommendations were level B (n = 6), 39.3 % were C (n = 11), 10.7 % were D (n = 3) and 28.6 % were I (n = 8). The interventions with the highest level of recommendation included delivery at a hospital with high cesarean hysterectomy volume, implementation of a standardized hospital protocol, delivery via a planned procedure, neuraxial anesthesia, and transverse skin incision (all level B recommendations by USPSTF criteria). CONCLUSIONS: Development of a standardized hospital protocol, delivery at a center with high CH surgical volume, and utilization of neuraxial anesthesia garnered B evidence levels. Recommendations were limited due to the lack of prospective trials. Further research into the technical aspects of this high-risk procedure is warranted.

Bile duct ligation impairs visual acuity in rats by ammonia- and bilirubin-induced retinal degeneration.

Patients with hepatic failure are often accompanied by hepatic retinopathy, but the cellular and molecular mechanisms underlying the hepatic retinopathy remain unclear. In this study, we investigated how liver failure leads to hepatic retinopathy using bile duct ligation (BDL) rats as a cholestasis animal model. Light-dark box test was used to assess sensitivity to light, indexed as visual acuity. On D28 post-BDL, rats were subjected to light-dark box test and blood samples were collected for biochemical analyses. The rats then were euthanized. Liver, spleen and both side of eye were quickly harvested. We showed that BDL impaired rat sensitivity to light, significantly decreased the thickness of inner nuclear layer (INL), outer nuclear layer (ONL) and total retina, as well as the retinal cell numbers in ONL and ganglion cell layer (GCL). The expression of rhodopsin (RHO), brn-3a and GPX4 was significantly decreased in retina of BDL rats, whereas the expression of cleaved caspase 3, 8, 9, bax/bcl-2, RIP1, GFAP, and iba-1, as well as TUNEL-positive cells were significantly increased. In cultured retinal explant, we found that NH4Cl (0.2, 1, 5 mM) concentration-dependently impaired activity of retinal explant, decreased thickness of INL and ONL, downregulated expression of brn-3a, RHO and GFAP, increased expression of cl-caspase 3 and TUNEL-positive cell numbers, with NH4Cl (5 mM) almost completely disrupting the structure of the cultured retina; bilirubin (1 µM) significantly upregulated GFAP expression, whereas high level (10 µM) of bilirubin downregulated expression of GFAP. We further demonstrated in vivo that hyperammonemia impaired rat sensitivity to light, decreased thickness of INL and ONL, downregulated expression of RHO, brn-3a, GFAP and increased expression of cl-caspase 3; hyperbilirubinemia impaired rat sensitivity to light, upregulated expression of GFAP and iba-1. In conclusion, BDL impaired rat visual acuity due to the elevated levels of ammonia and bilirubin. Ammonia induced loss of retinal ganglion cells and rod photoreceptor cells via apoptosis-mediated cell death. Bilirubin impaired retinal function via activating microglia and Müller cells.

Ablation of Mitophagy Receptor FUNDC1 Accentuates Septic Cardiomyopathy through ACSL4-Dependent Regulation of Ferroptosis and Mitochondrial Integrity.

Sepsis evokes compromised myocardial function prompting heart failure albeit target therapy remains dismal. Our study examined the possible role of mitophagy receptor FUNDC1 in septic cardiomyopathy. A sepsis model was established using cecal ligation and puncture (CLP) in FUNDC1 knockout (FUNDC1-/-) and WT mice prior to the evaluation of cardiac morphology, echocardiographic and cardiomyocyte contractile, oxidative stress, apoptosis, necroptosis, and ferroptosis. RNAseq analysis depicted discrepant patterns in mitophagy, oxidative stress and ferroptosis between CLP-challenged and control murine hearts. Septic patients displayed cardiac injury alongside low plasma FUNDC1 and iron levels. CLP evoked interstitial fibrosis, cardiac dysfunction (lowered ejection fraction, fractional shortening, shortening/relengthening velocity, peak shortening and electrically-stimulated intracellular Ca2+ rise, alongside increased LV end systolic diameter and relengthening duration), O2- buildup, apoptosis, necroptosis, and ferroptosis (downregulated GPX4 and SLC7A11), the responses of which were accentuated by FUNDC1 ablation. In particular, levels of lipid peroxidation enzyme acyl-CoA synthetase long-chain family member 4 (ACSL4) were upregulated following CLP procedure, with a more pronounced response in FUNDC1-/- mice. Co-immunoprecipitation and interaction interface revealed an evident interaction between FUNDC1 and ACSL4. In vitro studies revealed that the endotoxin lipopolysaccharide provoked cardiomyocyte contractile and lipid peroxidation anomalies, the responses were reversed by the mitophagy inducer oleanolic acid, inhibition of ACSL4 and ferroptosis. These findings favor a role for FUNDC1-ACSL4-ferroptosis cascade in septic cardiomyopathy.

Comparison of Different Animal Models in Hindlimb Functional Recovery after Acute Limb Ischemia-Reperfusion Injury.

Acute limb ischemia (ALI) is a sudden lack of blood flow to a limb, primarily caused by arterial embolism and thrombosis. Various experimental animal models, including non-invasive and invasive methods, have been developed and successfully used to induce limb ischemia-reperfusion injuries (L-IRI). However, there is no consensus on the methodologies used in animal models for L-IRI, particularly regarding the assessment of functional recovery. The present study aims to compare different approaches that induce L-IRI and determine the optimal animal model to study functional limb recovery. In this study, we applied a pneumatic cuff as a non-invasive method and ligated the aorta, iliac, or femoral artery as invasive methods to induce L-IRI. We have measured grip strength, motor function, creatine kinase level, inflammatory markers such as nuclear factor NF-κB, interleukin-6 (IL-6), hypoxia markers such as hypoxia-induced factor-1α (HIF-1α), and evaluated the muscle injury with hematoxylin and eosin (H&E) staining in Sprague Dawley rats after inducing L-IRI. The pneumatic pressure cuff method significantly decreased the muscle strength of the rats, causing the loss of ability to hold the grid and inducing significant limb function impairment, while artery ligations did not. We conclude from this study that the tourniquet cuff method could be ideal for studying functional recovery after L-IRI in the rat model.

Proximity ligation-triggered DNAzyme for selective fluorescent aptasensing of methicillin-resistant Staphylococcus aureus.

There is an urgent need for novel strategies to accurately and reliably detect pathogenic bacteria to address the global epidemic of antibiotic resistance. This study proposes an innovative approach combining dual aptamer-based target recognition and proximity ligation assay (PLA) triggered DNAzyme recycling cleavage. This method allows for the precise identification and reliable detection of methicillin-resistant Staphylococcus aureus (MRSA). The fluorescence probe labeled with a fluorophore is modified on gold nanoparticles (AuNPs), resulting in the quenching of the fluorescent signal by the AuNPs. The interaction between MRSA and two aptamers leads to forming a Mg2+-dependent DNAzyme. The DNAzyme cleaves the fluorescence probe, causing the fluorescent fragment to detach from the surface of the AuNPs, in which the quenched fluorescence signal in the fluorescence probe reappears. The DNAzyme-assisted cleavage and rebinding process generates a processive strolling along the surface track of AuNPs. Consequently, the fluorescence intensity experiences a substantial recovery. A strong linear correlation is observed between the fluorescence intensity and MRSA concentration within 50 cfu/mL to 106 cfu/mL. We believe that implementing the novel integrated strategy will broaden the range of bacterial detection methods in the battlefield environment and stimulate the creation of potential new drugs in the future.

Differential responses in the core, active site and peripheral regions of cytochrome c peroxidase to extreme pressure and temperature.

In consideration of life in extreme environments, the effects of hydrostatic pressure on proteins at the atomic level have drawn substantial interest. Large deviations of temperature and pressure from ambient conditions can shift the free energy landscape of proteins to reveal otherwise lowly populated structural states and even promote unfolding. We report the crystal structure of the heme-containing peroxidase, cytochrome c peroxidase (CcP) at 1.5 and 3.0 kbar and make comparisons to structures determined at 1.0 bar and cryo-temperatures (100 K). Pressure produces anisotropic changes in CcP, but compressibility plateaus after 1.5 kbar. CcP responds to pressure with volume declines at the periphery of the protein where B-factors are relatively high but maintains nearly intransient core structure, hydrogen bonding interactions and active site channels. Changes in active-site solvation and heme ligation reveal pressure sensitivity to protein-ligand interactions and a potential docking site for the substrate peroxide. Compression at the surface affects neither alternate side-chain conformers nor B-factors. Thus, packing in the core, which resembles a crystalline solid, limits motion and protects the active site, whereas looser packing at the surface preserves side-chain dynamics. These data demonstrate that conformational dynamics and packing densities are not fully correlated in proteins and that encapsulation of cofactors by the polypeptide can provide a precisely structured environment resistant to change across a wide range of physical conditions.