Acta Pharmacologica Sinica最新文献

Adenosine A_2A receptor (A_2AR) plays a pivotal role in the regulation of sleep-wake behaviors. We previously reported an A_2AR selective antagonist compound 38 with an IC₅₀ value of 29.0 nM. In this study, we investigated its effect on sleep-wake regulation in mice. Wild-type (WT) mice were administered compound 38 (3.3, 5.0, 7.5, 15, 30 mg/kg, i.p.) at 9:00, and electroencephalography and electromyography were simultaneously recorded. We showed that administration of compound 38 exhibited a dose-dependent effect on wakefulness promotion. To investigate the impact of compound 38 on sleep rebound, we conducted a 6 h (13:00-19:00) sleep deprivation experiment. We found that administration of compound 38 (30 mg/kg) produced a wakefulness-promoting effect lasting for 1 h. Subsequently, we explored the critical role of A_2AR in the wakefulness-promoting effect of compound 38 using A_2AR knockout (KO) mice and their WT littermates. We found that compound 38 enhanced wakefulness in WT mice, but did not have an arousal-promoting effect in A_2AR KO mice, suggesting that the arousal-promoting effect of compound 38 was mediated by A_2AR. We conducted immunohistochemistry and selectively ablated A_2AR-positive neurons using cell type-specific caspase-3 expression, which revealed an essential role of A_2AR-positive neurons in the nucleus accumbens shell for the arousal-promoting effect of compound 38. In conclusion, as a novel A_2AR antagonist, compound 38 promotes wakefulness in mice via the A_2AR and exhibits promising applications for further advancements in the field of sleep-wake disorders.

Psoriasis is a chronic, systemic immune-mediated skin disease. Although many new strategies for psoriasis treatment have been developed, there is great need in clinic for treating psoriasis. Gentiopicroside (GPS), derived from Gentiana manshurica Kitagawa, has multiple pharmacological activities including anti-inflammatory, anti-oxidative and antiviral activities. In this study, we investigated the potential effects of GPS in imiquimod (IMQ)-induced psoriasis mouse model and the underlying mechanisms. The mice were sensitized on their shaved back with IMQ cream for 7 days with or without topical application of 1% or 2% GPS cream. We showed that the application of GPS cream significantly ameliorated psoriasis-like skin lesions; GPS effect was better than that of calcipotriol. GPS rectified the immune cells infiltration and keratinocytes activation in the skin lesions, and significantly inhibited TNF-α/IFN-γ stimulated human keratinocyte (HaCaT) activation in vitro. Proteomic analysis from keratinocytes with and without GPS treatment prompted that GPS regulated the Keap1-Nrf2 pathway, which was the most important pathway in regulating oxidative stress and inflammation. We demonstrated that GPS regulated the protein expression of p62 and Keap1, induced Nrf2 nuclear translocation followed by transcription of Nrf2 downstream antioxidant genes in HaCaT cells. Furthermore, the antioxidant effects of GPS were abolished in Nrf2^-/- keratinocytes. Simultaneously, Nrf2^-/- mice showed increased psoriasiform symptoms with a diminished protective effect in response to GPS treatment. Collectively, the study discloses that GPS inhibits keratinocyte activation and ameliorates psoriasis-like skin lesions in an Nrf2-dependent manner.

The current treatments and drugs of myocardial infarction (MI) remain insufficient. In recent years, natural products have garnered significant attention for their potential in treating cardiovascular diseases due to their availability and lower toxicity. Saponins, in particular, showed promising effects for cardiac protection. In this study, we investigated the therapeutic effects of the saponin compound madecassoside in the treatment of MI, and underlying molecular mechanisms. The acute MI model was established in male mice by ligation of the left anterior descending coronary artery. The mice were treated with madecassoside (20 mg· kg^-1 ·d^-1, i.g.) for 14 days. After sacrificing the mice, hearts were harvested for analysis. We showed that madecassoside administration significantly mitigated cardiac function decline in MI mice by promoting angiogenesis and inhibiting myocardial cell apoptosis and fibrosis. By conducting systems pharmacology and RNA sequencing, we demonstrated that madecassoside upregulated SPARC gene expression by activating protein kinase C-β (PKCB) that had a strong promoting effect on endothelial cell angiogenesis, thus playing a crucial protective role against MI. We showed that inhibition of SPARC gene significantly reduced madecassoside-stimulated migration and tube formation of endothelial cells in vitro; co-administration of the PKCB-specific inhibitor ruboxistaurin (10 mg· kg^-1 ·d^-1, i.g.) abolished the cardioprotective effect of madecassoside in MI mice, validating the critical role of the PKCB/SPARC signaling pathway. This study demonstrates that madecassoside regulates the PKCB/SPARC pathway, promotes the proliferation and regeneration of vascular endothelial cells, and effectively alleviates the symptoms of MI.

The ability of the mammalian kidney to repair or regenerate after acute kidney injury (AKI) is very limited. The maladaptive repair of AKI promotes progression to chronic kidney disease (CKD). Therefore, new strategies to promote the repair/regeneration of injured renal tubules after AKI are urgently needed. Hypoxia has been shown to induce heart regeneration in adult mice. However, it is unknown whether hypoxia can induce kidney regeneration after AKI. In this study, we used a prolyl hydroxylase domain inhibitor (PHDI), MK-8617, to mimic hypoxic conditions and found that MK-8617 significantly ameliorated ischemia reperfusion injury (IRI)-induced AKI. We also showed that MK-8617 dramatically facilitated renal tubule regeneration by promoting the proliferation of renal proximal tubular cells (RPTCs) after IRI-induced AKI. We then performed bulk mRNA sequencing and discovered that multiple nephrogenesis-related genes were significantly upregulated with MK-8617 pretreatment. We also showed that MK-8617 may alleviate proximal tubule injury by stabilizing the HIF-1α protein specifically in renal proximal tubular cells. Furthermore, we demonstrated that MK-8617 promotes the reprogramming of renal proximal tubular cells to Sox9⁺ renal progenitor cells and the regeneration of renal proximal tubules. In summary, we report that the inhibition of prolyl hydroxylase improves renal proximal tubule regeneration after IRI-induced AKI by promoting the reprogramming of renal proximal tubular cells to Sox9⁺ renal progenitor cells.

Ubiquitin fold modifier 1 (UFM1) is a newly identified post-translational modifier that is involved in the UFMylation process. Similar to ubiquitination, UFMylation enables the conjugation of UFM1 to specific target proteins, thus altering their stability, activity, or localization. UFM1 chains have the potential to undergo cleavage from their associated proteins via UFM1-specific proteases, thus highlighting a reversible feature of UFMylation. This modification is conserved across nearly all eukaryotic organisms, and is associated with diverse biological activities such as hematopoiesis and the endoplasmic reticulum stress response. The disruption of UFMylation results in embryonic lethality in mice and is associated with various human diseases, thus underscoring its essential role in embryonic development, tissue morphogenesis, and organismal homeostasis. In this review, we aim to provide an in-depth overview of the UFMylation system, its importance in disease processes, and its potential as a novel target for therapeutic intervention.

Glutamine synthetase (GS) plays a crucial role in the homeostasis of the glutamate-glutamine cycle in the brain. Hypoactive GS causes depressive behaviors. Under chronic stress, GS has no change in expression, but its activity is decreased due to nitration of tyrosine (Tyr). Thus, we speculate that agents that prevent nitration or facilitate denitration of GS would be candidates for new antidepressants. Using human recombinant GS and mouse lysate from the medial prefrontal cortex, we demonstrated that Tyr (0.0313-0.5 µM) dose-dependently protected GS activity against peroxynitrite-induced Tyr-nitration of GS. Diet supplementation with Tyr exerted significant antidepressant effects in a chronic immobilization stress depression mouse model. We further found that dipeptides, such as tyrosyl-glutamine (YQ), that had appropriate chemical properties for medication also increased GS activity both in vitro and in vivo and exerted antidepressant effects. Because reduced GS activity also occurs in epilepsy and hyperammonemia, we evaluated whether Tyr and YQ had therapeutic effects. Interestingly, Tyr or YQ administration significantly attenuated kainic acid-induced seizures in mice and reduced blood ammonia levels in azoxymethane- or bile duct ligation-induced hyperammonemia mouse models, which was accompanied by an increment in GS activity. The activation of GS was accomplished by a decrement in Tyr-nitration, so-called Tyr-denitration. Therefore, this study demonstrates that the activation of GS could be a new strategy to treat depression and other GS-related diseases.

Gastric cancer is a malignant gastrointestinal disease characterized by high morbidity and mortality rates worldwide. The occurrence and progression of gastric cancer are influenced by various factors, including the abnormal alternative splicing of key genes. Recently, RBM39 has emerged as a tumor biomarker that regulates alternative splicing in several types of cancer. However, the specific functions and key alternative splicing events modulated by RBM39 in gastric cancer are still unclear. In this work, bioinformatic analysis of The Cancer Genome Atlas (TCGA) database and immunoblotting of patient tissue samples revealed that RBM39 was highly expressed in gastric cancer tissues and that its elevated expression significantly reduced overall patient survival. Cell-line-based and tumor xenograft experiments demonstrated that RBM39 knockdown attenuated the growth of gastric cancer cells both in vitro and in vivo. Mechanistically, through RNA-seq, minigene, and RT‒PCR, we discovered and further validated that RBM39 inhibited exon 3 skipping, thereby modulating the splicing of MRPL33. The long isoform MRPL33-L, which includes exon 3, but not the short isoform MRPL33-S, which lacks exon 3, significantly promoted the proliferation and colony formation of gastric cancer cells. Furthermore, we observed an increased percent-splice-in (PSI) of MRPL33 in gastric cancer tissues. Genetic manipulation and pharmacological treatment with the RBM39 degrader indisulam demonstrated that RBM39 regulated cell proliferation by influencing the splicing switch of MRPL33 in gastric cancer cells and a xenograft mouse model. Our findings indicate that RBM39 regulates the oncogenic splicing of MRPL33 and suggest that it may serve as a potential therapeutic target for gastric cancer.

Sorting nexins (SNXs) as the key regulators of sorting cargo proteins are involved in diverse diseases. SNXs can form the specific reverse vesicle transport complex (SNXs-retromer) with vacuolar protein sortings (VPSs) to sort and modulate recovery and degradation of cargo proteins. Our previous study has shown that SNX3-retromer promotes both STAT3 activation and nuclear translocation in cardiomyocytes, suggesting that SNX3 might be a critical regulator in the heart. In this study we investigated the role of SNX3 in the development of pathological cardiac hypertrophy and heart failure. We generated abdominal aortic constriction (AAC) rat model and transverse aortic constriction (TAC) mouse model; hypertrophic neonatal rat cardiomyocytes (NRCMs) were induced by exposure to isoproterenol (10 μM). We showed that the expression of SNX3 was significantly upregulated in ISO-treated NRCMs and in the failing heart of AAC rats. Overexpression of SNX3 by intramyocardial injection of Ad-SNX3 induced heart failure in rats, and increased the susceptibility of NRCMs to ISO-induced myocardial injury in vitro. In contrast, conditional knockout of SNX3 in cardiac tissue in mice rescued the detrimental heart function in TAC mice, and knockdown of SNX3 protected against ISO-induced injury in NRCMs and AAC rats. We then conducted immunoprecipitation-based mass spectrometry and localized surface plasmon resonance, and demonstrated a direct interaction between SNX3-retromer and high mobility group box 1 (HMGB1), which mediated the efflux of nuclear HMGB1. Moreover, overexpression of HMGB1 in NRCMs inhibited the pro-hypertrophic effects of SNX3, whereas knockdown of HMGB1 abolished the protective effect of SNX3-deficiency. These results suggest that HMGB1 might be a direct cargo protein of SNX3-retromer, and its interaction with SNX3 promotes its efflux from the nucleus, leading to the pathological development of heart failure.

Regulated cell death like pyroptosis is one vital cause of diabetic cardiomyopathy (DCM), which eventually leads to heart failure. Tumor necrosis factor (TNF) receptor-associated death domain protein (TRADD) is an adapter protein with multiple functions that participates in the pathophysiological progress of different cardiovascular disorders via regulating regulated cell death. Studies have shown that TRADD combines with receptor-interacting protein kinase 3 (RIPK3) and facilitates its activation, thereby mediating TNF-induced necroptosis. However, no direct relationship between TRADD and pyroptosis has been identified. In this study, we investigated the role and mechanisms of TRADD in pyroptosis during DCM. We established a streptozotocin (STZ)-induced diabetic mouse model and high glucose (HG)-treated cardiomyocytes model. We showed that the expression levels of TRADD were significantly increased in the hearts of diabetic mice and HG-treated cardiomyocytes. Knockdown of TRADD did not affect blood glucose and triglyceride levels, but significantly improved cardiac function, and attenuated myocardial hypertrophy, fibrosis, and pyroptosis in the heart of diabetic mice. Furthermore, both knockdown of TRADD and application of TRADD inhibitor apostatin-1 (Apt-1, 10 μM) significantly ameliorated cell injury and pyroptosis in HG-treated cardiomyocytes. We demonstrated that HG treatment increased the expression of X-box binding protein 1 (XBP1) and enhanced the binding of XBP1 to the TRADD promoter to elevate TRADD expression in the cardiomyocytes. Collectively, this study provides evidence that TRADD-mediated pyroptosis contributes to DCM, suggesting that strategies to inhibit TRADD activity may be a novel approach for DCM treatment.