Presynaptic Excitation via GABAB Receptors in Habenula Cholinergic Neurons Regulates Fear Memory Expression.

Fear behaviors are regulated by adaptive mechanisms that dampen their expression in the absence of danger. By studying circuits and the molecular mechanisms underlying this adaptive response, we show that cholinergic neurons of the medial habenula reduce fear memory expression through GABAB presynaptic excitation. Ablating these neurons or inactivating their GABAB receptors impairs fear extinction in mice, whereas activating the neurons or their axonal GABAB receptors reduces conditioned fear. Although considered exclusively inhibitory, here, GABAB mediates excitation by amplifying presynaptic Ca(2+) entry through Cav2.3 channels and potentiating co-release of glutamate, acetylcholine, and neurokinin B to excite interpeduncular neurons. Activating the receptors for these neurotransmitters or enhancing neurotransmission with a phosphodiesterase inhibitor reduces fear responses of both wild-type and GABAB mutant mice. We identify the role of an extra-amygdalar circuit and presynaptic GABAB receptors in fear control, suggesting that boosting neurotransmission in this pathway might ameliorate some fear disorders.

Brain endothelial GSDMD activation mediates inflammatory BBB breakdown.

The blood-brain barrier (BBB) protects the central nervous system from infections or harmful substances1; its impairment can lead to or exacerbate various diseases of the central nervous system2-4. However, the mechanisms of BBB disruption during infection and inflammatory conditions5,6 remain poorly defined. Here we find that activation of the pore-forming protein GSDMD by the cytosolic lipopolysaccharide (LPS) sensor caspase-11 (refs. 7-9), but not by TLR4-induced cytokines, mediates BBB breakdown in response to circulating LPS or during LPS-induced sepsis. Mice deficient in the LBP-CD14 LPS transfer and internalization pathway10-12 resist BBB disruption. Single-cell RNA-sequencing analysis reveals that brain endothelial cells (bECs), which express high levels of GSDMD, have a prominent response to circulating LPS. LPS acting on bECs primes Casp11 and Cd14 expression and induces GSDMD-mediated plasma membrane permeabilization and pyroptosis in vitro and in mice. Electron microscopy shows that this features ultrastructural changes in the disrupted BBB, including pyroptotic endothelia, abnormal appearance of tight junctions and vasculature detachment from the basement membrane. Comprehensive mouse genetic analyses, combined with a bEC-targeting adeno-associated virus system, establish that GSDMD activation in bECs underlies BBB disruption by LPS. Delivery of active GSDMD into bECs bypasses LPS stimulation and opens the BBB. In CASP4-humanized mice, Gram-negative Klebsiella pneumoniae infection disrupts the BBB; this is blocked by expression of a GSDMD-neutralizing nanobody in bECs. Our findings outline a mechanism for inflammatory BBB breakdown, and suggest potential therapies for diseases of the central nervous system associated with BBB impairment.

PNLDC1 catalysis and postnatal germline function are required for piRNA trimming, LINE1 silencing, and spermatogenesis in mice.

PIWI-interacting RNAs (piRNAs) play critical and conserved roles in transposon silencing and gene regulation in the animal germline. Three distinct piRNA populations are present during mouse spermatogenesis: fetal piRNAs in fetal/perinatal testes, pre-pachytene and pachytene piRNAs in postnatal testes. PNLDC1 is required for piRNA 3' end maturation in multiple species. However, whether PNLDC1 is the bona fide piRNA trimmer and the physiological role of 3' trimming of different piRNA populations in spermatogenesis in mammals remain unclear. Here, by inactivating Pnldc1 exonuclease activity in vitro and in mice, we reveal that the PNLDC1 trimmer activity is essential for spermatogenesis and male fertility. PNLDC1 catalytic activity is required for both fetal and postnatal piRNA 3' end trimming. Despite this, postnatal piRNA trimming but not fetal piRNA trimming is critical for LINE1 transposon silencing. Furthermore, conditional inactivation of Pnldc1 in postnatal germ cells causes LINE1 transposon de-repression and spermatogenic arrest in mice, indicating that germline-specific postnatal piRNA trimming is essential for transposon silencing and germ cell development. Our findings highlight the germ cell-intrinsic role of PNLDC1 and piRNA trimming in mammals to safeguard the germline genome and promote fertility.

Precious Metal Free Hydrogen Evolution Catalyst Design and Application.

The quest to identify precious metal free hydrogen evolution reaction catalysts has received unprecedented attention in the past decade. In this Review, we focus our attention to recent developments in precious metal free hydrogen evolution reactions in acidic and alkaline electrolyte owing to their relevance to commercial and near-commercial low-temperature electrolyzers. We provide a detailed review and critical analysis of catalyst activity and stability performance measurements and metrics commonly deployed in the literature, as well as review best practices for experimental measurements (both in half-cell three-electrode configurations and in two-electrode device testing). In particular, we discuss the transition from laboratory-scale hydrogen evolution reaction (HER) catalyst measurements to those in single cells, which is a critical aspect crucial for scaling up from laboratory to industrial settings but often overlooked. Furthermore, we review the numerous catalyst design strategies deployed across the precious metal free HER literature. Subsequently, we showcase some of the most commonly investigated families of precious metal free HER catalysts; molybdenum disulfide-based, transition metal phosphides, and transition metal carbides for acidic electrolyte; nickel molybdenum and transition metal phosphides for alkaline. This includes a comprehensive analysis comparing the HER activity between several families of materials highlighting the recent stagnation with regards to enhancing the intrinsic activity of precious metal free hydrogen evolution reaction catalysts. Finally, we summarize future directions and provide recommendations for the field in this area of electrocatalysis.

Phosphorylation of EZH2 by AMPK Suppresses PRC2 Methyltransferase Activity and Oncogenic Function.

Sustained energy starvation leads to activation of AMP-activated protein kinase (AMPK), which coordinates energy status with numerous cellular processes including metabolism, protein synthesis, and autophagy. Here, we report that AMPK phosphorylates the histone methyltransferase EZH2 at T311 to disrupt the interaction between EZH2 and SUZ12, another core component of the polycomb repressive complex 2 (PRC2), leading to attenuated PRC2-dependent methylation of histone H3 at Lys27. As such, PRC2 target genes, many of which are known tumor suppressors, were upregulated upon T311-EZH2 phosphorylation, which suppressed tumor cell growth both in cell culture and mouse xenografts. Pathologically, immunohistochemical analyses uncovered a positive correlation between AMPK activity and pT311-EZH2, and higher pT311-EZH2 correlates with better survival in both ovarian and breast cancer patients. Our finding suggests that AMPK agonists might be promising sensitizers for EZH2-targeting cancer therapies.

Metformin Promotes Antitumor Immunity via Endoplasmic-Reticulum-Associated Degradation of PD-L1.

Metformin has been reported to possess antitumor activity and maintain high cytotoxic T lymphocyte (CTL) immune surveillance. However, the functions and detailed mechanisms of metformin's role in cancer immunity are not fully understood. Here, we show that metformin increases CTL activity by reducing the stability and membrane localization of programmed death ligand-1 (PD-L1). Furthermore, we discover that AMP-activated protein kinase (AMPK) activated by metformin directly phosphorylates S195 of PD-L1. S195 phosphorylation induces abnormal PD-L1 glycosylation, resulting in its ER accumulation and ER-associated protein degradation (ERAD). Consistently, tumor tissues from metformin-treated breast cancer patients exhibit reduced PD-L1 levels with AMPK activation. Blocking the inhibitory signal of PD-L1 by metformin enhances CTL activity against cancer cells. Our findings identify a new regulatory mechanism of PD-L1 expression through the ERAD pathway and suggest that the metformin-CTLA4 blockade combination has the potential to increase the efficacy of immunotherapy.

MIWI N-terminal RG motif promotes efficient pachytene piRNA production and spermatogenesis independent of LINE1 transposon silencing.

PIWI proteins and their associated piRNAs act to silence transposons and promote gametogenesis. Murine PIWI proteins MIWI, MILI, and MIWI2 have multiple arginine and glycine (RG)-rich motifs at their N-terminal domains. Despite being known as docking sites for the TDRD family proteins, the in vivo regulatory roles for these RG motifs in directing PIWI in piRNA biogenesis and spermatogenesis remain elusive. To investigate the functional significance of RG motifs in mammalian PIWI proteins in vivo, we genetically engineered an arginine to lysine (RK) point mutation of a conserved N-terminal RG motif in MIWI in mice. We show that this tiny MIWI RG motif is indispensable for piRNA biogenesis and male fertility. The RK mutation in the RG motif disrupts MIWI-TDRKH interaction and impairs enrichment of MIWI to the intermitochondrial cement (IMC) for efficient piRNA production. Despite significant overall piRNA level reduction, piRNA trimming and maturation are not affected by the RK mutation. Consequently, MiwiRK mutant mice show chromatoid body malformation, spermatogenic arrest, and male sterility. Surprisingly, LINE1 transposons are effectively silenced in MiwiRK mutant mice, indicating a LINE1-independent cause of germ cell arrest distinctive from Miwi knockout mice. These findings reveal a crucial function of the RG motif in directing PIWI proteins to engage in efficient piRNA production critical for germ cell progression and highlight the functional importance of the PIWI N-terminal motifs in regulating male fertility.

Directed differentiation of human embryonic stem cells into conjunctival epithelial cells.

Severe conjunctival damage can lead to extensive ocular cicatrisation, fornix shortening, and even ocular surface failure, resulting in significant vision impairment. Conjunctival reconstruction is the primary therapeutic strategy for these clinical conjunctival diseases. However, there have been limited studies on induced differentiation of conjunctival epithelial cells derived from stem cells. In this study, we established a chemical defined differentiation protocol from human embryonic stem cells (hESCs) into conjunctival epithelial cells. hES cell line H1 was used for differentiation, and RT-qPCR, immunofluorescence staining, Periodic-acid-Schiff staining (PAS), and transcriptome analysis were employed to identify the differentiated cells. Here, to imitate the development of the vertebrate conjunctiva, hESCs were induced using a three-step process involving first chetomin was used to induce ocular surface ectoderm, then nicotinamide was used to induce ocular surface epithelial progenitor cells, and finally epidermal growth factor, keratinocyte growth factor and other factors were used to differentiate mature conjunctival epithelial cells. hESC-derived conjunctival epithelial cells expressed mature conjunctival epithelial lineage markers (including PAX6, P63, K13). The presence of goblet cells was confirmed by positive PAS. Transcriptome analysis revealed that hESC-derived conjunctival epithelial cells possessed a more naïve phenotype, and exhibited greater proliferation capacity compared to mature human conjunctival epithelial cells, suggesting their potential as alternative seed cells for conjunctival reconstruction.

Phylogeny and evolution of hemipteran insects based on expanded genomic and transcriptomic data.

BACKGROUND: Hemiptera is the fifth species-rich order of insects and the most species-rich order of hemimetabolous insects, including numerous insect species that are of agricultural or medical significance. Despite much effort and recent advance in inferring the Hemiptera phylogeny, some high-level relationships among superfamilies remain controversial. RESULTS: We sequenced the genomes of 64 hemipteran species from 15 superfamilies and the transcriptomes of two additional scale insect species, integrating them with existing genomic and transcriptomic data to conduct a comprehensive phylogenetic analysis of Hemiptera. Our datasets comprise an average of 1625 nuclear loci of 315 species across 27 superfamilies of Hemiptera. Our analyses supported Cicadoidea and Cercopoidea as sister groups, with Membracoidea typically positioned as the sister to Cicadoidea + Cercopoidea. In most analyses, Aleyrodoidea was recovered as the sister group of all other Sternorrhyncha. A sister-group relationship was supported between Coccoidea and Aphidoidea + Phylloxeroidea. These relationships were further supported by four-cluster likelihood mapping analyses across diverse datasets. Our ancestral state reconstruction indicates phytophagy as the primary feeding strategy for Hemiptera as a whole. However, predation likely represents an ancestral state for Heteroptera, with several phytophagous lineages having evolved from predatory ancestors. Certain lineages, like Lygaeoidea, have undergone a reversal transition from phytophagy to predation. Our divergence time estimation placed the diversification of hemipterans to be between 60 and 150 million years ago. CONCLUSIONS: By expanding phylogenomic taxon sampling, we clarified the superfamily relationships within the infraorder Cicadomorpha. Our phylogenetic analyses supported the sister-group relationship between the superfamilies Cicadoidea and Cercopoidea, and the superfamily Membracoidea as the sister to Cicadoidea + Cercopoidea. Our divergence time estimation supported the close association of hemipteran diversification with the evolutionary success and adaptive radiation of angiosperms during the Cretaceous period.

Cyclic guanosine monophosphate-adenosine monophosphate synthetase/stimulator of interferon genes signaling aggravated corneal allograft rejection through neutrophil extracellular traps.

The activation of innate immunity following transplantation has been identified as a crucial factor in allograft inflammation and rejection. However, the role of cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)/stimulator of interferon genes (STING) signaling-mediated innate immunity in the pathogenesis of allograft rejection remains unclear. Utilizing a well-established murine model of corneal transplantation, we demonstrated increased expression of cGAS and STING in rejected-corneal allografts compared with syngeneic (Syn) and normal (Nor) corneas, along with significant activation of the cGAS/STING pathway, as evidenced by the enhanced phosphorylation of TANK-binding kinase 1and interferon regulatory factor 3. Pharmacological and genetic inhibition of cGAS/STING signaling markedly delayed corneal transplantation rejection, resulting in prolonged survival time and reduced inflammatory infiltration. Furthermore, we observed an increase in the formation of neutrophil extracellular traps (NETs) in rejected allografts, and the inhibition of NET formation through targeting peptidylarginine deiminase 4 and DNase I treatment significantly alleviated immune rejection and reduced cGAS/STING signaling activity. Conversely, subconjunctival injection of NETs accelerated corneal transplantation rejection and enhanced the activation of the cGAS/STING pathway. Collectively, these findings demonstrate that NETs contribute to the exacerbation of allograft rejection via cGAS/STING signaling, highlighting the targeting of the NETs/cGAS/STING signaling pathway as a potential strategy for prolonging allograft survival.

Multicolor Tuning of Perylene Diimides Dyes for Targeted Organelle Imaging In Vivo.

The adjustment of the emission wavelengths and cell permeability of the perylene diimides (PDI) for multicolor cell imaging is a great challenge. Herein, based on a bay-region substituent engineering strategy, multicolor perylene diimides (MCPDI) were rationally designed and synthesized by introducing azetidine substituents on the bay region of PDIs. With the fine-tuned electron-donating ability of the azetidine substituents, these MCPDI showed high brightness, orange, red, and near infrared (NIR) fluorescence along with Stokes shifts increasing from 35 to 110 nm. Interestingly, azetidine substituents distorted to the plane of the MCPDI dyes, and the twist angle of monosubstituted MCPDI was larger than that of disubstituted MCPDI, which might efficiently decrease their π-π stacking. Moreover, all of these MCPDI dyes were cell-permeable and selectively stained various organelles for multicolor imaging of multiple organelles in living cells. Two-color imaging of lipid droplets (LDs) and other organelles stained with MCPDI dyes was performed to reveal the interaction between the LDs and other organelles in living cells. Furthermore, a NIR-emitting MCPDI dye with a mitochondria-targeted characteristic was successfully applied for tumor-specific imaging. The facile synthesis, excellent stability, high brightness, tunable fluorescence emission, and Stokes shifts make these MCPDI promising fluorescent probes for biological applications.

MADS-box protein PpDAM6 regulates chilling requirement-mediated dormancy and bud break in peach.

Bud dormancy is crucial for winter survival and is characterized by the inability of the bud meristem to respond to growth-promotive signals before the chilling requirement (CR) is met. However, our understanding of the genetic mechanism regulating CR and bud dormancy remains limited. This study identified PpDAM6 (DORMANCY-ASSOCIATED MADS-box) as a key gene for CR using a genome-wide association study analysis based on structural variations in 345 peach (Prunus persica (L.) Batsch) accessions. The function of PpDAM6 in CR regulation was demonstrated by transiently silencing the gene in peach buds and stably overexpressing the gene in transgenic apple (Malus × domestica) plants. The results showed an evolutionarily conserved function of PpDAM6 in regulating bud dormancy release, followed by vegetative growth and flowering, in peach and apple. The 30-bp deletion in the PpDAM6 promoter was substantially associated with reducing PpDAM6 expression in low-CR accessions. A PCR marker based on the 30-bp indel was developed to distinguish peach plants with non-low and low CR. Modification of the H3K27me3 marker at the PpDAM6 locus showed no apparent change across the dormancy process in low- and non-low- CR cultivars. Additionally, H3K27me3 modification occurred earlier in low-CR cultivars on a genome-wide scale. PpDAM6 could mediate cell-cell communication by inducing the expression of the downstream genes PpNCED1 (9-cis-epoxycarotenoid dioxygenase 1), encoding a key enzyme for ABA biosynthesis, and CALS (CALLOSE SYNTHASE), encoding callose synthase. We shed light on a gene regulatory network formed by PpDAM6-containing complexes that mediate CR underlying dormancy and bud break in peach. A better understanding of the genetic basis for natural variations of CR can help breeders develop cultivars with different CR for growing in different geographical regions.

Long non-coding RNA LINC00491 accelerates head and neck squamous cell carcinoma progression through regulating miR-508-3p/SATB1 axis and activating Wnt signaling pathway.

Head and neck squamous cell carcinoma (HNSCC) is the most common malignancy of the head and neck epidermis. Accumulating long non-coding RNAs (lncRNAs) have been proven to be involved in the occurrence and development of HNSCC. LncRNA long intergenic non-protein coding RNA 491 (LINC00491) has been confirmed to regulate the progression of some cancers. In our study, we aimed to explore the potential biological function of LINC00491 and expound the regulatory mechanism by which LINC00491 affects the progression of HNSCC. RT-qPCR was utilized to analyze the expression of LINC00491 in HNSCC cell lines and the normal cell line. Functionally, we carried out a series of assays to measure cell proliferation, apoptosis, migration and invasion, such as EdU assay, colony formation, wound healing and western blot assays. Also, mechanism assays including RNA pull down and RIP were also implemented to investigate the interaction of LINC00491 and RNAs. As a result, we discovered that LINC00491 was highly expressed in HNSCC cells. In addition, LINC00491 depletion suppressed cell proliferation, migration and EMT process. Furthermore, we discovered that LINC00491 could bind to miR-508-3p. MiR-508-3p overexpression can restrain HNSCC cell growth. Importantly, miR-508-3p can target SATB homeobox 1 (SATB1) in HNSCC cells. Further, Wnt signaling pathway was proved to be activated by LINC00491 through SATB1 in HNSCC cells. In a word, LINC00491 accelerated HNSCC progression through regulating miR-508-3p/SATB1 axis and activating Wnt signaling pathway.

Seminal Vesicle-Derived Exosomes for the Regulation of Sperm Activity.

The seminal vesicle contributes to a large extent of the semen volume and composition. Removal of seminal vesicle or lack of seminal vesicle proteins leads to decreased fertility. Seminal plasma proteome revealed that seminal fluid contained a wide diversity of proteins. Many of them are known to modulate sperm capacitation and serve as capacitation inhibitors or decapacitation factors. Despite identifying secretory vesicles from the male reproductive tract, such as epididymosomes or prostasomes, isolation, identification, and characterization of seminal vesicle-derived exosomes are still unknown. This chapter aims to review the current understanding of the function of seminal vesicles on sperm physiology and male reproduction and provide ultracentrifugation-based isolation protocols for the isolation of seminal vesicle exosomes. Moreover, via proteomic analysis and functional categorization, a total of 726 proteins IDs were identified in the purified seminal vesicle exosomes fraction. Preliminary data showed seminal vesicle-derived exosomes inhibited sperm capacitation; however, more studies will be needed to reveal other functional involvements of seminal vesicle-derived exosomes on the sperm physiology and, more importantly, how these exosomes interact with sperm membrane to achieve their biological effects.

Experimental Direct Quantum Fidelity Learning via a Data-Driven Approach.

Fidelity estimation is an important technique for evaluating prepared quantum states in noisy quantum devices. A recent theoretical work proposed a frugal approach called neural quantum fidelity estimation (NQFE) [X. Zhang et al., Phys. Rev. Lett. 127, 130503 (2021).PRLTAO0031-900710.1103/PhysRevLett.127.130503]. While this requires a much smaller number of measurement operators than full quantum state tomography, it uses a weight-based floating measurement strategy that predetermines the top global Pauli operators that contribute the most to the fidelity and uses discrete fidelity intervals as predictions. In this Letter, we develop a measurement-fixed NQFE based on a transformer model which requires less measurement cost and can output continuous estimates of fidelity. Here we further experimentally apply the NQFE in a realistic situation using a nuclear spin quantum processor. We prepare the ground states of local Hamiltonians and arbitrary states and investigate how to estimate their fidelity with reference states, and we compare the fidelity estimation strategy with our and the original NQFE to conventional tomography. It is shown that NQFE can estimate the fidelity with comparable accuracy to the tomography approach. In the future, NQFE will become an important tool for benchmarking quantum states ahead of the advent of well-trusted fault-tolerant quantum computers.

The ocular immunological alterations in the process of high-risk corneal transplantation rejection.

PURPOSE: This study aims to reveal the immunopathogenesis of the high-risk corneal transplantation using a comparative proteomic approach. METHODS: The immunological properties of ocular tissues (including corneal grafts, aqueous humour, and iris-ciliary body) were analysed using a high-risk rabbit corneal transplantation model employing a comparative proteomic approach. RESULTS: The corneal grafts revealed a dramatic increase in the immune response both at the early (postoperative day 7) and rejection stages, along with the appearance of transplantation stress-induced cellular senescence in the early stage. The aqueous humour (AH) displayed persistent pathological alterations, indicated by the significant enrichment of complement and coagulation cascades pathway in the early stage and interleukin (IL)-17 signalling pathway in the rejection stage. More surprisingly, the pronounced elevation of immune response was also observed in the iris-ciliary body (I-CB) tissues at the early and rejection stages. The enriched immune-related pathways were associated with antigen processing and presentation, complement and coagulation cascades, and IL-17 signalling pathway. Furthermore, proteomic analysis revealed that the implantation of Cyclosporine A drug delivery system (CsA-DDS) into the anterior chamber obviously mitigated corneal transplantation rejection by inhibiting immunoreaction both in the corneal grafts and I-CB tissues. CONCLUSION: The results highlighted the involvement of intraocular immunity both in the grafts and I-CB tissues during corneal transplantation rejection, further suggesting the anterior chamber as an optimal drug-delivery site for its treatment.

Carbon monoxide-releasing molecule-3 ameliorates traumatic brain injury-induced cardiac dysfunctions via inhibition of pyroptosis and apoptosis.

Traumatic brain injury (TBI) frequently results in cardiac dysfunction and impacts the quality of survivors' life. It has been reported that carbon monoxide-releasing molecule-3 (CORM-3) administration immediately after hemorrhagic shock and resuscitation (HSR) ameliorated the HSR­induced cardiac dysfunctions. The purpose of this study was to determine whether the application of CORM-3 on TBI exerted therapeutic effects against TBI-induced cardiac dysfunctions. Rats were randomly divided into four groups (n = 12) including Sham, TBI, TBI/CORM-3 and TBI/inactive CORM-3 (iCORM-3) groups. TBI was established by a weight-drop model. The rats in the TBI/CORM-3 group and TBI/iCORM-3 group were intravenously injected with CORM-3 and iCORM-3 (4 mg/kg) following TBI, respectively. The time of death in the rats that did not survive within 24 h was recorded. 24 h post-trauma, the cardiac function, pathological change, serum troponin T and creatine kinase-MB (CK-MB) levels, pyroptosis, apoptosis and expressions of TUNEL staining, Gasdermin D (GSDMD), IL-1ß, IL-18, ratio Bax/Bcl-2 were assessed by echocardiography, hematoxylin-eosin staining, chemiluminescence, immunofluorescence, and western blot assays, respectively. TBI-treated rats exhibited dramatically decreased ejection fraction and aggravated myocardial injury, increased mortality rate, elevated levels of serum troponin T and CK-MB, promoted cardiac pyroptosis and apoptosis, and upregulated expressions of cleaved caspase-3, GSDMD N-terminal fragments, IL-1ß, IL-18, and ratio of Bax/Bcl-2, whereas CORM-3 partially reversed these changes. CORM-3 ameliorated TBI-induced cardiac injury and dysfunction. This mechanism may be responsible for the inhibition of pyroptosis and apoptosis in cardiomyocyte.

Hirudin ameliorates myocardial ischemia-reperfusion injury in a rat model of hemorrhagic shock and resuscitation: roles of NLRP3-signaling pathway.

Severe hemorrhage shock and resuscitation (HSR) has been reported to induce myocardial ischemia-reperfusion injury (MIRI), resulting in a poor prognosis. Hirudin, an effective thrombin inhibitor, can offer protection against MIRI. This study aimed to determine if hirudin administration ameliorates HSR-induced MIRI and the underlying mechanism. A rat model of HSR was established by bleeding rats to a mean arterial blood pressure of 30-35 mmHg for 45 min and then resuscitating them with all the shed blood through the left femoral vein. After HSR, 1 mg/kg of hirudin was administrated immediately. At 24 h after HSR, the cardiac injury was assessed using serum CK-MB, cTnT, hematoxylin-eosin (HE) staining, echocardiography, M1-polarized macrophages, and pyroptosis-associated factors, including cleaved caspase-1, Gasdermin D (GSDMD) N-terminal, IL-1ß, and IL-18 were measured by immunofluorescence and western blot assays. Nigericin, a unique agonist, was utilized to evaluate the responsibilities of NLRP3 signaling. Under the HSR condition, rats exhibited a significant increase in myocardial injury score, an elevation of serum cTnT, CK-MB levels, an aggrandization of M1-polarized macrophages, an upregulation of pyroptosis-associated factors, including cleaved caspase-1, GSDMD N-terminal, IL-1ß, and IL-18, but a significant decrease in left ventricular ejection fraction (EF%) and a reduction of left ventricular fractional shortening (FS%), while hirudin administration partially restored the changes. However, the NLRP3 agonist nigericin reversed the cardioprotective effects of hirudin. We determined the cardioprotective effects of hirudin against HSR-induced MIRI. The mechanism may involve the inhibition of NLRP3-induced pyroptosis.

Lewis Acid-Promoted Oxidative Cleavage of Carbon-Carbon Bonds: Synthesis of N-Arylated Lactam-Type Iminosugars.

In this paper, a mild strategy for the oxidative cleavage of carbon-carbon bonds catalyzed by Lewis acid was developed in air condition at room temperature. Under such conditions, the bis-carbonyl compounds 3 were directly afforded from the reaction of D-ribose tosylate 1 and aniline in excellent yields through the oxidative cleavage of the key intermediate iminium-ion A and its tautomer enamine B. A series of N-arylated lactam-type iminosugars 5 were then successfully obtained by removing the isopropylidene group from 3 with the aid of the condensation agent DCC. Additionally, reduction of A and the removal of the isopropylidene group could provide N-arylated iminosugars 4. This strategy enables the oxidative cleavage of carbon-carbon bonds under mild conditions and facilitates the synthesis of the novel iminosugars with potent biological activity.

One-Pot Stereoselective Synthesis of the Naphthofurano-Iminosugars via a [3 + 2] Cycloaddition Reaction.

This study presents the synthesis of novel naphthofurano-iminosugars (4) using 2,3-O-isopropylidene D-ribose tosylate (1a), anilines (2), and 1,4-benzoquinone (3a) as starting materials through key iminium ion/enamine intermediates via [3 + 2] cyclization reactions at room temperature. The reaction has unique regioselectivity and stereoselectivity with moderate to excellent yields. The adaptability of this method has been demonstrated using various substituted anilines, on which both electron-donating and electron-withdrawing groups were well employed in the reactions. Notably, the treatment of the fused multicyclic iminosugar 4 with TFA efficiently leads to an interesting unexpected pyridinium salt (8), possible via four sequential steps: deprotection of the 2,3-O-isopropylidene group, furan ring opening, dehydration condensation of the OH groups, and elimination of water.