Manipulating PTPRD function with ectodomain antibodies.

Protein tyrosine phosphatases (PTPs) are critical regulators of signal transduction but have yet to be exploited fully for drug development. Receptor protein tyrosine phosphatase δ (RPTPδ/PTPRD) has been shown to elicit tumor-promoting functions, including elevating SRC activity and promoting metastasis in certain cell contexts. Dimerization has been implicated in the inhibition of receptor protein tyrosine phosphatases (RPTPs). We have generated antibodies targeting PTPRD ectodomains with the goal of manipulating their dimerization status ectopically, thereby regulating intracellular signaling. We have validated antibody binding to endogenous PTPRD in a metastatic breast cancer cell line, CAL51, and demonstrated that a monoclonal antibody, RD-43, inhibited phosphatase activity and induced the degradation of PTPRD. Similar effects were observed following chemically induced dimerization of its phosphatase domain. Mechanistically, RD-43 triggered the formation of PTPRD dimers in which the phosphatase activity was impaired. Subsequently, the mAb-PTPRD dimer complex was degraded through lysosomal and proteasomal pathways, independently of secretase cleavage. Consequently, treatment with RD-43 inhibited SRC signaling and suppressed PTPRD-dependent cell invasion. Together, these findings demonstrate that manipulating RPTP function via antibodies to the extracellular segments has therapeutic potential.

The glycemic gap as a prognostic indicator in cardiogenic shock: a retrospective cohort study.

BACKGROUND: Stress-induced hyperglycemia (SIH) is associated with poor outcomes in cardiogenic shock (CS), and there have been inconsistent results among patients with or without diabetes mellitus (DM). The glycemic gap (GG) is derived by subtracting A1c-derived average glucose from blood glucose levels; it is a superior indicator of SIH. We aimed to explore the role of GG in the outcomes of patients with CS. METHODS: Data on patients diagnosed with CS were extracted from the MIMIC-IV v2.0 database to investigate the relationship between GG and 30-day mortality (Number of absolute GG subjects = 359; Number of relative GG subjects = 357). CS patients from the Second Affiliated Hospital of Wenzhou Medical University were enrolled to explore the correlation between GG and lactic acid (Number of absolute GG subjects = 252; Number of relative GG subjects = 251). Multivariate analysis, propensity score-matched (PSM) analysis, inverse probability treatment weighting (IPTW), and Pearson correlation analysis were applied. RESULTS: Absolute GG was associated with 30-day all-cause mortality in CS patients (HRadjusted: 1.779 95% CI: 1.137-2.783; HRPSM: 1.954 95% CI: 1.186-3.220; HRIPTW: 1.634 95% CI: 1.213-2.202). The higher the absolute GG level, the higher the lactic acid level (ßadjusted: 1.448 95% CI: 0.474-2.423). A similar trend existed in relative GG (HRadjusted: 1.562 95% CI: 1.003-2.432; HRPSM: 1.790 95% CI: 1.127-2.845; HRIPTW: 1.740 95% CI: 1.287-2.352; ßadjusted:1.294 95% CI: 0.369-2.219). Subgroup analysis showed that the relationship existed irrespective of DM. The area under the curve of GG combined with the Glasgow Coma Scale (GCS) for 30-day all-cause mortality was higher than that of GCS (absolute GG: 0.689 vs. 0.637; relative GG: 0.688 vs. 0.633). GG was positively related to the triglyceride-glucose index. Kaplan-Meier curves revealed that groups of higher GG with DM had the worst outcomes. The outcomes differed among races and GG levels (all P < 0.05). CONCLUSIONS: Among patients with CS, absolute and relative GGs were associated with increased 30-day all-cause mortality, regardless of DM. The relationship was stable after multivariate Cox regression analysis, PSM, and IPTW analysis. Furthermore, they reflect the severity of CS to some extent. Hyperlactatemia and insulin resistance may underlie the relationship between stress-induced hyperglycemia and poor outcomes in CS patients. They both improve the predictive efficacy of the GCS.

α-Synuclein induces deficiency in clathrin-mediated endocytosis through inhibiting synaptojanin1 expression.

Parkinson's disease (PD) is an age-related chronic neurological disorder, mainly characterized by the pathological feature of α-synuclein (α-syn) aggregation, with the exact disease pathogenesis unclear. During the onset and progression of PD, synaptic dysfunction, including dysregulation of axonal transport, impaired exocytosis, and endocytosis are identified as crucial events of PD pathogenesis. It has been reported that over-expression of α-syn impairs clathrin-mediated endocytosis (CME) in the synapses. However, the underlying mechanisms still needs to be explored. In this study, we investigated the molecular events underlying the synaptic dysfunction caused by over-expression of wild-type human α-syn and its mutant form, involving series of proteins participating in CME. We found that excessive human α-syn causes impaired fission and uncoating of clathrin-coated vesicles during synaptic vesicle recycling, leading to reduced clustering of synaptic vesicles near the active zone and increased size of plasma membrane and number of endocytic intermediates. Furthermore, over-expressed human α-syn induced changes of CME-associated proteins, among which synaptojanin1 (SYNJ1) showed significant reduction in various brain regions. Over-expression of SYNJ1 in primary hippocampal neurons from α-syn transgenic mice recovered the synaptic vesicle density, clustering and endocytosis. Using fluorescence-conjugated transferrin, we demonstrated that SYNJ1 re-boosted the CME activity by restoring the phosphatidylinositol-4,5-bisphosphate homeostasis. Our data suggested that over-expression of α-syn disrupts synaptic function through interfering with vesicle recycling, which could be alleviated by re-availing of SYNJ1. Our study unrevealed a molecular mechanism of the synaptic dysfunction in PD pathogenesis and provided a potential therapeutic target for treating PD.

3,4-benzopyrene aggravates myocardial ischemia-reperfusion injury-induced pyroptosis through inhibition of autophagy-dependent NLRP3 degradation.

Polycyclic aromatic hydrocarbons (PAHs) are produced during combustion of organic matter, such as during cigarette smoking, and they exist widely in the environment. Exposure to 3,4-benzo[a]pyrene (BaP), as the most widely studied PAHs, relates to many cardiovascular diseases. However, the underlying mechanism of its involvement remains largely unclear. In this study, we developed a myocardial ischemia-reperfusion (I/R) injury mouse model and an oxygen and glucose deprivation-reoxygenation H9C2 cell model to evaluate the effect of BaP in I/R injury. After BaP exposure, the expression of autophagy-related proteins, the abundance of NLRP3 inflammasomes, and the degree of pyroptosis were measured. Our results show that BaP aggravates myocardial pyroptosis in a autophagy-dependent manner. In addition, we found that BaP activates the p53-BNIP3 pathway via the aryl hydrocarbon receptor to decrease autophagosome clearance. Our findings present new insights into the mechanisms underlying cardiotoxicity and reveal that the p53-BNIP3 pathway, which is involved in autophagy regulation, is a potential therapeutic target for BaP-induced myocardial I/R injury. Because PAHs are omnipresent in daily life, the toxic effects of these harmful substances should not be underestimated.

A comparison of fluid status determination using bioelectric impedance and the isotope dilution method in hemodialysis and peritoneal dialysis patients.

We aimed to compare fluid status as determined by multifrequency bioimpedance spectroscopy (MF-BIS, Xitron 4200, USA) with that determined by the isotope dilution method among a contemporary Chinese cohort. Healthy Chinese subjects (HS, n = 30) were recruited in Zhengzhou. Hemodialysis (HD, n = 49) and peritoneal dialysis (PD, n = 48) patients were screened at the First Affiliated Hospital of Zhengzhou University. Total body water (TBW) and extracellular water (ECW) were measured by deuterium (TBWD) and bromide (ECWBr) dilution, respectively, and by MF-BIS using the Moissl equation (ME). The results of MF-BIS were compared to the reference method by Pearson analysis and Bland-Altman analysis in the three groups. The accuracy of overhydration as determined by MF-BIS was analyzed by receiver operating characteristic (ROC) curves. The TBWD and TBWME values were 34.67 ± 7.31 and 35.41 ± 5.76 L, 37.30 ± 8.58 and 37.02 ± 8.10 L, and 38.61 ± 10.02 and 38.44 ± 7.59 L in the HS, HD and PD groups, respectively. The ECWBr and ECWME values were 14.88 ± 3.33 and 15.53 ± 2.39 L, 16.24 ± 5.08 and 16.90 ± 3.93 L, and 19.08 ± 6.41 and 18.23 ± 3.61 L in the HS, HD and PD groups, respectively. The mean bias between TBWD and TBWME was -0.74 L, 0.28 L, and 0.17 L in the HS, HD and PD groups, respectively. The mean bias between ECWBr and ECWME was -0.65 L, -0.66 L, and 0.85 L in the HS, HD and PD groups, respectively. Compared to the ECWBr/TBWD ratio, the area under the ROC curve (AUC) of the ECWME/TBWME ratio for the diagnosis of overhydration was 0.76 and 0.68 in the HD and PD groups, respectively. In summary, MF-BIS with ME could be used in Chinese HD and PD patients.

3'-(Phenyl alkynyl) analogs of abscisic acid: synthesis and biological activity of potent ABA antagonists.

We report here the synthesis and biological testing of 3'-(phenyl alkynyl) abscisic ABA analogs, a new class of potent ABA antagonists. These ABA analogs incorporate a rigid framework of eight carbon atoms attached at the 3'-carbon atom of ABA that prevents folding of the ABA analog-bound receptor required for ABA signalling. The two-step synthesis is based upon the optimized conversion of natural (S)-ABA to 3'-iodo ABA which can be coupled to phenyl acetylenes using Sonogashira conditions, or to styryl compounds through Suzuki chemistry. The parent 3'-(phenyl alkynyl) ABA analog 7 was obtained in 29% yield, 74% yield based on recovered starting material. In a lentil seed germination assay, compound 7 was found to have more potent activity than other known 3'-substituted ABA antagonists to date. In a structure activity study parasubstituted phenyl alkynyl analogs had comparable activity to the analog 7 while the 3'-styryl ABA 18 was only slightly less active. Analog 7 overcame ABA inhibition of germination and seedling growth in a wide range of mono and dicot plant species, including canola, lentil, soybean, rice, wheat, barley, cannabis and canary seed. 3'-(Phenyl alkynyl) ABA analogs have numerous potential practical agricultural applications including promoting ripening of crops, dormancy breaking of seeds and woody perennials, as well as promoting seed germination, and growth under stress conditions as demonstrated in this report.

Tenascin-C promotes acute kidney injury to chronic kidney disease progression by impairing tubular integrity via αvß6 integrin signaling.

Tenascin-C is an extracellular matrix glycoprotein that plays a critical role in kidney fibrosis by orchestrating a fibrogenic niche. Here, we demonstrate that tenascin-C is a biomarker and a mediator of kidney fibrogenesis by impairing tubular integrity. Tenascin-C was found to be increased in kidney biopsies from patients with chronic kidney disease (CKD). In a cohort of 225 patients with CKD, the urinary tenascin-C level was markedly elevated, compared to 39 healthy individuals. Moreover, the level of urinary tenascin-C in CKD was correlated with the severity of kidney dysfunction and fibrosis. In mouse model of acute kidney injury-to-CKD induced by ischemia/reperfusion, depletion of tenascin-C preserved tubular integrity and ameliorated renal fibrotic lesions. In vitro, tenascin-C impaired tubular cell integrity by inducing partial epithelial-mesenchymal transition. Using decellularized kidney tissue scaffolds, we found that tenascin-C-enriched scaffolds facilitated tubular epithelial-mesenchymal transition ex vivo. Mechanistically, tenascin-C specifically induced integrins αvß6 in tubular cells and activated focal adhesion kinase (FAK). Blocking αvß6 integrins or inhibition of FAK restored tubular integrity by repressing epithelial-mesenchymal transition and alleviated kidney fibrosis. Thus, our studies underscore that tenascin-C is a noninvasive biomarker of kidney fibrogenesis and a pathogenic mediator that impairs tubular integrity. Hence, blockade of the tenascin-C/αvß6 integrin/FAK signal cascade may be a novel strategy for therapeutic intervention of kidney fibrosis.

Candidate foraging gene orthologs in a lower termite, Reticulitermes flavipes.

Under a sociogenomic context, the molecular mechanisms underlying gene-behavior associations are of particular interest. The Drosophila foraging (for) gene has been demonstrated to have a causal role in insect behavioral plasticity. Previous studies of for have revealed many facets of for function, including roles in foraging, energy metabolism, learning and memory, circadian rhythm, and stress resistance. for orthologs have been identified in a variety of insect taxa. However, expression patterns are not consistent across all insects, with for orthologs serving as both positive and negative regulators of foraging behavior. In this study, we cloned two for orthologs, Rffor-α and Rffor-ß, from the Eastern subterranean termite, Reticulitermes flavipes. Spatial distribution study showed that the termite brain possesses significantly higher expression levels of Rffor-α and Rffor-ß than other types of tissues, which suggests that for may act on the brain to influence an individual's ability to respond to its environment. The temporal expression profile of Rffor across different developmental stages suggests that Rffor functions as a negative regulator of foraging behavior. However, results from environmental impacts, that is, temperature and photoperiod, do not fit under a model of negative correlation between gene expression and locomotion. Further testing is warranted to better understand the interaction between Rffor expression and the environment.

Sarmentosin alleviates doxorubicin-induced cardiotoxicity and ferroptosis via the p62-Keap1-Nrf2 pathway.

Doxorubicin (Dox) is extensively used as an antitumor agent, but its severe cardiotoxicity significantly limits its clinical use. Current treatments for Dox-induced cardiotoxicity are inadequate, necessitating alternative solutions. This study evaluated the effects of sarmentosin, a compound from Sedum sarmentosum, on Dox-induced cardiotoxicity and dysfunction. Sarmentosin was administered as a pretreatment to both mice and H9c2 cells before Dox exposure. Subsequently, markers of Dox-induced cardiotoxicity and ferroptosis in serum and cell supernatants were measured. Western blot analysis was utilized to detect levels of ferroptosis, oxidative stress, and autophagy proteins. Additionally, echocardiography, hematoxylin-eosin staining, ROS detection, and immunofluorescence techniques were employed to support our findings. Results demonstrated that sarmentosin significantly inhibited iron accumulation, lipid peroxidation, and oxidative stress, thereby reducing Dox-induced ferroptosis and cardiotoxicity in C57BL/6 mice and H9c2 cells. The mechanism involved the activation of autophagy and the Nrf2 signaling pathway. These findings suggest that sarmentosin may prevent Dox-induced cardiotoxicity by mitigating ferroptosis. The study underscores the potential of compounds like sarmentosin in treating Dox-induced cardiotoxicity.

m6A RNA methylation drives kidney fibrosis by upregulating ß-catenin signaling.

N6-methyladenosine (m6A) methylation plays a crucial role in various biological processes and the pathogenesis of human diseases. However, its role and mechanism in kidney fibrosis remain elusive. In this study, we show that the overall level of m6A methylated RNA was upregulated and the m6A methyltransferase METTL3 was induced in kidney tubular epithelial cells in mouse models and human kidney biopsies of chronic kidney disease (CKD). Proximal tubule-specific knockout of METTL3 in mice protected kidneys against developing fibrotic lesions after injury. Conversely, overexpression of METTL3 aggravated kidney fibrosis in vivo. Through bioinformatics analysis and experimental validation, we identified ß-catenin mRNA as a major target of METTL3-mediated m6A modification, which could be recognized by a specific m6A reader, the insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3). METTL3 stabilized ß-catenin mRNA, increased ß-catenin protein and induced its downstream profibrotic genes, whereas either knockdown of IGF2BP3 or inhibiting ß-catenin signaling abolished its effects. Collectively, these results indicate that METTL3 promotes kidney fibrosis by stimulating the m6A modification of ß-catenin mRNA, leading to its stabilization and its downstream profibrotic genes expression. Our findings suggest that targeting METTL3/IGF2BP3/ß-catenin pathway may be a novel strategy for the treatment of fibrotic CKD.

The Neutrophil Percentage-to-Albumin Ratio is Associated with All-Cause Mortality in Patients with Atrial Fibrillation: A Retrospective Study.

Objective: The present study aimed to evaluate the relationship between all-cause mortality and the neutrophil percentage-to-albumin ratio (NPAR) in patients with atrial fibrillation (AF). Methods: We obtained clinical information from patients with AF from the Medical Information Mart for Intensive Care-IV version 2.0 (MIMIC-IV) database and the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University (WMU). The clinical endpoints were all-cause death measured at 30-day, 90-day, and one-year intervals. For endpoints associated with the NPAR, logistic regression models were used to calculate odds ratios (OR) with 95% confidence intervals (CI). Receiver operating characteristic (ROC) curves and area under the curve (AUC) were developed to compare the ability of different inflammatory biomarkers to predict 90-day mortality in patients with AF. Results: Higher NPAR was associated with a higher risk of 30-day (OR 2.08, 95% CI 1.58-2.75), 90-day (OR 2.07, 95% CI 1.61-2.67), and one-year mortality (OR 1.60, 95% CI 1.26-2.04) in patients with AF in 2813 patients from MIMIC-IV. The predictive performance of NPAR (AUC = 0.609) for 90-day mortality was better than that of neutrophil-to-lymphocyte ratio (NLR) (AUC = 0.565, P < 0.001), and platelet-to-lymphocyte ratio (PLR) (AUC = 0.528, P < 0.001). When NPAR and sequential organ failure assessment (SOFA) were combined, the AUC increased from 0.609 to 0.674 (P < 0.001). Higher NPAR was associated with a higher risk of 30-day mortality (OR 2.54, 95% CI 1.02-6.30) and 90-day mortality (OR 2.76, 95% CI 1.09-7.01) in 283 patients from WMU. Conclusion: An increased 30-day, 90-day, and one-year mortality risk among patients with AF were linked to a higher NPAR in MIMIC-IV. NPAR was thought to be a good predictor of 90-day all-cause mortality. Higher NPAR was associated with a higher risk of 30-day and 90-day mortality in WMU.

3,4-benzo[a]pyrene aggravates myocardial infarction injury by activating NLRP3-related pyroptosis through PINK1/Parkin-mitophagy-mPTP opening axis.

BACKGROUND: Air pollution is an important and interventionable risk factor for cardiovascular disease. Air pollution exposure, even for a short-term exposure, is conspicuously relevant to increased risk of myocardial infarction (MI) mortality and clinical evidence has shown that air pollution particulate matter (PM) induces the aggravation of AMI. 3,4-benzo[a]pyrene (BaP), an extremely toxic polycyclic aromatic hydrocarbon (PAH) and a common component of PM, is listed as one of the main objects of environmental pollution monitoring. Both epidemiological and toxicological studies suggest that BaP exposure may be associated with cardiovascular disease. Since PM is significantly associated with the increased risk of MI mortality, and BaP is an important component of PM associated with cardiovascular disease, we intend to investigate the effect of BaP on MI models. METHODS: The MI mouse model and the oxygen and glucose deprivation (OGD) H9C2 cell model were used to investigate the effect of BaP in MI injury. The involvement of mitophagy and pyroptosis in regulating deterioration of cardiac function and aggravation of MI injury induced by BaP was comprehensively evaluated. RESULTS: Our study shows that BaP exacerbates MI injury in vivo and in vitro, a result based on BaP-induced NLRP3-related pyroptosis. In addition, BaP can inhibit PINK1/Parkin dependent mitophagy through the aryl hydrocarbon receptor (AhR), thus the mitochondrial permeability transition pore (mPTP) was induced to open. CONCLUSION: Our results suggest a role for the BaP from air pollution in MI injury aggravation and reveal that BaP aggravates MI injury by activating NLRP3-related pyroptosis via the PINK1/Parkin-mitophagy-mPTP opening axis.

Limonin ameliorates cisplatin-induced acute liver injury by inhibiting 11ß-hydroxysteroid dehydrogenase type 1.

BACKGROUND: Acute liver injury (ALI) is a common side effect of cisplatin treatment in the clinic and can lead to liver failure if not treated promptly. Previous studies have revealed that Limonin, a critical bioactive substance in citrus fruits, can protect multiple organs from various medical conditions. However, whether Limonin could ameliorate cisplatin-induced ALI remains unclear. METHODS: In vivo and in vitro models were induced by cisplatin in the present study. Non-targeted metabolomics was employed to analyze the metabolic changes in the liver after ALI. In addition, molecular docking was utilized to predict the potential targets of Limonin. RESULTS: Limonin attenuated hepatic histopathological injury by reducing hepatocyte apoptosis, lipid peroxidation, and inflammation in cisplatin-challenged mice. Employing metabolomics, we revealed that Limonin mediated the balance of various disturbed metabolic pathways in the liver after cisplatin-induced ALI. Integrating public data mining, molecular docking studies, and in vitro experiments demonstrated that Limonin suppressed the expression and activity of its direct target, 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1), in the liver, thus reducing the production of corticosterone (CORT), a key metabolite promoted hepatocyte apoptosis. CONCLUSIONS: Limonin improves the liver metabolic microenvironment by inhibiting 11ß-HSD1 to protect against cisplatin-induced ALI.

Insulin-like growth factor 2 mRNA-binding protein 3 promotes kidney injury by regulating ß-catenin signaling.

Wnt/ß-catenin is a developmental signaling pathway that plays a crucial role in driving kidney fibrosis after injury. Activation of ß-catenin is presumed to be regulated through the posttranslational protein modification. Little is known about whether ß-catenin is also subjected to regulation at the posttranscriptional mRNA level. Here, we report that insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) plays a pivotal role in regulating ß-catenin. IGF2BP3 was upregulated in renal tubular epithelium of various animal models and patients with chronic kidney disease. IGF2BP3 not only was a direct downstream target of Wnt/ß-catenin but also was obligatory for transducing Wnt signal. In vitro, overexpression of IGF2BP3 in kidney tubular cells induced fibrotic responses, whereas knockdown of endogenous IGF2BP3 prevented the expression of injury and fibrosis markers in tubular cells after Wnt3a stimulation. In vivo, exogenous IGF2BP3 promoted ß-catenin activation and aggravated kidney fibrosis, while knockdown of IGF2BP3 ameliorated renal fibrotic lesions after obstructive injury. RNA immunoprecipitation and mRNA stability assays revealed that IGF2BP3 directly bound to ß-catenin mRNA and stabilized it against degradation. Furthermore, knockdown of IGF2BP3 in tubular cells accelerated ß-catenin mRNA degradation in vitro. These studies demonstrate that IGF2BP3 promotes ß-catenin signaling and drives kidney fibrosis, which may be mediated through stabilizing ß-catenin mRNA. Our findings uncover a previously underappreciated dimension of the complex regulation of Wnt/ß-catenin signaling and suggest a potential target for therapeutic intervention of fibrotic kidney diseases.

CXCR4 induces podocyte injury and proteinuria by activating ß-catenin signaling.

Background: C-X-C chemokine receptor type 4 (CXCR4) plays a crucial role in mediating podocyte dysfunction, proteinuria and glomerulosclerosis. However, the underlying mechanism remains poorly understood. Here we studied the role of ß-catenin in mediating CXCR4-triggered podocyte injury. Methods: Mouse models of proteinuric kidney diseases were used to assess CXCR4 and ß-catenin expression. We utilized cultured podocytes and glomeruli to delineate the signal pathways involved. Conditional knockout mice with podocyte-specific deletion of CXCR4 were generated and used to corroborate a role of CXCR4/ß-catenin in podocyte injury and proteinuria. Results: Both CXCR4 and ß-catenin were induced and colocalized in the glomerular podocytes in several models of proteinuric kidney diseases. Activation of CXCR4 by its ligand SDF-1α stimulated ß-catenin activation but did not affect the expression of Wnt ligands in vitro. Blockade of ß-catenin signaling by ICG-001 preserved podocyte signature proteins and inhibited Snail1 and MMP-7 expression in vitro and ex vivo. Mechanistically, activation of CXCR4 by SDF-1α caused the formation of CXCR4/ß-arrestin-1/Src signalosome in podocytes, which led to sequential phosphorylation of Src, EGFR, ERK1/2 and GSK-3ß and ultimately ß-catenin stabilization and activation. Silencing ß-arrestin-1 abolished this cascade of events and inhibited ß-catenin in response to CXCR4 stimulation. Podocyte-specific knockout of CXCR4 in mice abolished ß-catenin activation, preserved podocyte integrity, reduced proteinuria and ameliorated glomerulosclerosis after Adriamycin injury. Conclusion: These results suggest that CXCR4 promotes podocyte dysfunction and proteinuria by assembling CXCR4/ß-arrestin-1/Src signalosome, which triggers a cascade of signal events leading to ß-catenin activation.

PTP1B inhibitors protect against acute lung injury and regulate CXCR4 signaling in neutrophils.

Acute lung injury (ALI) can cause acute respiratory distress syndrome (ARDS), a lethal condition with limited treatment options and currently a common global cause of death due to COVID-19. ARDS secondary to transfusion-related ALI (TRALI) has been recapitulated preclinically by anti-MHC-I antibody administration to LPS-primed mice. In this model, we demonstrate that inhibitors of PTP1B, a protein tyrosine phosphatase that regulates signaling pathways of fundamental importance to homeostasis and inflammation, prevented lung injury and increased survival. Treatment with PTP1B inhibitors attenuated the aberrant neutrophil function that drives ALI and was associated with release of myeloperoxidase, suppression of neutrophil extracellular trap (NET) formation, and inhibition of neutrophil migration. Mechanistically, reduced signaling through the CXCR4 chemokine receptor, particularly to the activation of PI3Kγ/AKT/mTOR, was essential for these effects, linking PTP1B inhibition to promoting an aged-neutrophil phenotype. Considering that dysregulated activation of neutrophils has been implicated in sepsis and causes collateral tissue damage, we demonstrate that PTP1B inhibitors improved survival and ameliorated lung injury in an LPS-induced sepsis model and improved survival in the cecal ligation and puncture-induced (CLP-induced) sepsis model. Our data highlight the potential for PTP1B inhibition to prevent ALI and ARDS from multiple etiologies.

Intranasal administration of α-synuclein preformed fibrils triggers microglial iron deposition in the substantia nigra of Macaca fascicularis.

Iron deposition is present in main lesion areas in the brains of patients with Parkinson's disease (PD) and an abnormal iron content may be associated with dopaminergic neuronal cytotoxicity and degeneration in the substantia nigra of the midbrain. However, the cause of iron deposition and its role in the pathological process of PD are unclear. In the present study, we investigated the effects of the nasal mucosal delivery of synthetic human α-synuclein (α-syn) preformed fibrils (PFFs) on the pathogenesis of PD in Macaca fascicularis. We detected that iron deposition was clearly increased in a time-dependent manner from 1 to 17 months in the substantia nigra and globus pallidus, highly contrasting to other brain regions after treatments with α-syn PFFs. At the cellular level, the iron deposits were specifically localized in microglia but not in dopaminergic neurons, nor in other types of glial cells in the substantia nigra, whereas the expression of transferrin (TF), TF receptor 1 (TFR1), TF receptor 2 (TFR2), and ferroportin (FPn) was increased in dopaminergic neurons. Furthermore, no clear dopaminergic neuron loss was observed in the substantia nigra, but with decreased immunoreactivity of tyrosine hydroxylase (TH) and appearance of axonal swelling in the putamen. The brain region-enriched and cell-type-dependent iron localizations indicate that the intranasal α-syn PFFs treatment-induced iron depositions in microglia in the substantia nigra may appear as an early cellular response that may initiate neuroinflammation in the dopaminergic system before cell death occurs. Our data suggest that the inhibition of iron deposition may be a potential approach for the early prevention and treatment of PD.

Inhibition of copper transporter 1 prevents α-synuclein pathology and alleviates nigrostriatal degeneration in AAV-based mouse model of Parkinson's disease.

The formation of α-synuclein aggregates is a major pathological hallmark of Parkinson's disease. Copper promotes α-synuclein aggregation and toxicity in vitro. The level of copper and copper transporter 1, which is the only known high-affinity copper importer in the brain, decreases in the substantia nigra of Parkinson's disease patients. However, the relationship between copper, copper transporter 1 and α-synuclein pathology remains elusive. Here, we aim to decipher the molecular mechanisms of copper and copper transporter 1 underlying Parkinson's disease pathology. We employed yeast and mammalian cell models expressing human α-synuclein, where exogenous copper accelerated intracellular α-synuclein inclusions and silencing copper transporter 1 reduced α-synuclein aggregates in vitro, suggesting that copper transporter 1 might inhibit α-synuclein pathology. To study our hypothesis in vivo, we generated a new transgenic mouse model with copper transporter 1 conditional knocked-out specifically in dopaminergic neuron. Meanwhile, we unilaterally injected adeno-associated viral human-α-synuclein into the substantia nigra of these mice. Importantly, we found that copper transporter 1 deficiency significantly reduced S129-phosphorylation of α-synuclein, prevented dopaminergic neuronal loss, and alleviated motor dysfunction caused by α-synuclein overexpression in vivo. Overall, our data indicated that inhibition of copper transporter 1 alleviated α-synuclein mediated pathologies and provided a novel therapeutic strategy for Parkinson's disease and other synucleinopathies.

No symphony without bassoon and piccolo: changes in synaptic active zone proteins in Huntington's disease.

Prominent features of HD neuropathology are the intranuclear and cytoplasmic inclusions of huntingtin and striatal and cortical neuronal cell death. Recently, synaptic defects have been reported on HD-related studies, including impairment of neurotransmitter release and alterations of synaptic components. However, the definite characteristics of synapse dysfunction and the underlying mechanisms remain largely unknown. We studied the gene expression levels and patterns of a number of proteins forming the cytoskeletal matrix of the presynaptic active zones in HD transgenic mice (R6/1), in hippocampal neuronal cultures overexpressing mutant huntingtin and in postmortem brain tissues of HD patients. To investigate the interactions between huntingtin and active proteins, we performed confocal microscopic imaging and immunoprecipitation in mouse and HEK 293 cell line models. The mRNA and protein levels of Bassoon were reduced in mouse and cell culture models of HD and in brain tissues of patients with HD. Moreover, a striking re-distribution of a complex of proteins including Bassoon, Piccolo and Munc 13-1 from the cytoplasm and synapses into intranuclear huntingtin aggregates with loss of active zone proteins and dendritic spines. This re-localization was age-dependent and coincided with the formation of huntingtin aggregates. Using co-immunoprecipitation, we demonstrated that huntingtin interacts with Bassoon, and that this interaction is likely mediated by a third linking protein. Three structural proteins involved in neurotransmitter release in the presynaptic active zones of neurons are altered in expression and that the proteins are redistributed from their normal functional site into mutant huntingtin aggregates.

The Role of Urinary Angiotensinogen in Kidney Interstitial Inflammation and Renal Prognosis.

INTRODUCTION: Urinary angiotensinogen (uAGT) has been described as a novel biomarker of acute kidney injury (AKI) and chronic kidney disease (CKD). Renal interstitial inflammatory cell infiltration is a common renal pathological feature of AKI and CKD. However, the correlation between uAGT and renal interstitial inflammatory cell infiltration is unknown. The aim of this study was to analyze the expression of uAGT, its relationship with interstitial inflammatory cell infiltration, and prognosis in patients with renal insufficiency. METHODS: The expression of uAGT, urinary kidney injury molecule 1 (uKIM-1), and urinary neutrophil gelatinase-associated lipocalin (uNGAL) were examined by enzyme-linked immunosorbent assay (ELISA) at baseline and kidney pathology was evaluated at the same time. RESULTS: Sixty-five patients with renal insufficiency and 12 healthy controls were enrolled. uAGT, uKIM-1, and uNGAL levels were significantly higher compared with healthy participants. uAGT showed the strongest correlation with interstitial inflammatory cell infiltration (r = 0.366, P < .05). uAGT level was able to identify interstitial inflammatory cell infiltration with greater accuracy (AUC = 0.664, P < .05) than other urinary biomarkers. After a median follow-up of 22 months, 15 patients reached the composite renal endpoint. Kaplan meier survival curves followed by multivariate cox proportional hazards regression analysis showed that uAGT (> 166.8 ng/mg creatinine) independently predicted higher risk of the endpoint. CONCLUSION: uAGT may be used as a non-invasive biomarker of interstitial inflammatory cell infiltration and a strong predictor of renal prognosis in patients with renal insufficiency.