Acta Pharmacologica Sinica最新文献

Astrocytes are known to modulate synaptogenesis or neuronal activities, thus participating in mental functions. It has been shown that astrocytes are involved in the antidepressant mechanism. In this study we investigated the potential hormonal mediator governing the astrocyte-neuron interplay for stress-coping behaviors. Mice were subjected to chronic restraint stress (CRS) for 14 days, and then brain tissue was harvested for analyses. We found that the expression of pituitary adenylate cyclase activating polypeptide (PACAP) and its receptor PAC1 was significantly decreased in astrocytes of the prelimbic (PrL) cortex. By conducting a combination of genetics, in vivo imaging and behavioral assays we demonstrated that PAC1 in cortical astrocytes was necessary for maintaining normal resilience of mice against chronic environmental stress like restraint stress. Furthermore, we showed the enhancement of de novo cortical spine formation and synaptic activity under PACAP-mediated astrocytic activation possibly via the ATP release. The molecular mechanisms suggested that the vesicle homeostasis mediated by PACAP-PAC1 axis in astrocytes was involved in regulating synaptic functions. This study identifies a previously unrecognized route by which neuropeptide modulates cortical functions via local regulation of astrocytes.

G protein-coupled receptors (GPCRs) are critical drug targets involved in numerous physiological processes, yet many of their structures remain unresolved due to inherent flexibility and diverse ligand interactions. This study systematically evaluates the accuracy of AlphaFold3-predicted GPCR structures compared to experimentally determined structures, with a primary focus on ligand-bound states. Our analysis reveals that while AlphaFold3 shows improved performance over AlphaFold2 in predicting overall GPCR backbone architecture, significant discrepancies persist in ligand-binding poses, particularly for ions, peptides, and proteins. Despite advancements, these limitations constrain the utility of AlphaFold3 models in functional studies and structure-based drug design, where high-resolution details of ligand interactions are crucial. We assess the accuracy of predicted structures across various ligand types, quantifying deviations in binding pocket geometries and ligand orientations. Our findings highlight specific challenges in the computational prediction of ligand-bound GPCR structures, emphasizing areas where further refinement is needed. This study provides valuable insights for researchers using AlphaFold3 in GPCR studies, underscores the ongoing necessity for experimental structure determination, and offers direction for improving protein-ligand interaction predictions in future computational models.

As a pathological feature of diabetic kidney disease (DKD), dysregulated glomerular filtration barrier function could lead to the increased levels of proteinuria. The integrity of tight junctions (TJs) of glomerular endothelial cells (GECs) is a guarantee of physiological function of glomerular filtration barrier. Mammalian sterile 20-like kinase (MST1) is a key regulatory protein in the blood-brain barrier (BBB), and it regulates the expression of TJs-related proteins in cerebral vascular endothelial cells. Our previous study showed that MST1 was involved in renal tubulointerstitial fibrosis of DKD. In the present study we investigated the role of MST1 in barrier function of GECs of DKD, and explored its regulatory mechanisms. In kidney tissue section of DKD patients and db/db mice, and high glucose (HG)-cultured mouse glomerular endothelial cells (mGECs), we showed that MST1 was inactivated in the GECs of DKD accompanied by disrupted glomerular endothelial barrier. In db/db mice and HG-cultured mGECs, knockdown of MST1 increased proteinuria levels, and disrupted glomerular endothelial barrier through decreasing TJs-related proteins, whereas MST1 overexpression restored glomerular endothelial barrier through regaining TJs-related proteins. In db/db mice and HG-cultured mGECs, we demonstrated that MST1 inhibition induced TJs's disruption of GECs via activating YAP1/TEAD signaling. Verteporfin (an inhibitor of YAP1-TEAD interaction) and PY-60 (a YAP1 agonist) were used to verify the role of YAP1/TEAD signaling in the regulation effect of MST1 on barrier function of mGECs. In conclusion, MST1 activation recovers glomerular endothelial barrier of DKD by regaining TJs-related proteins via inhibiting YAP1/TEAD signaling. This study highlights the multiple regulation of MST1 activation on kidney injury.

Osimertinib, a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), has demonstrated significant clinical benefits in the treatment of EGFR-mutated non-small cell lung cancer (NSCLC). However, inevitable acquired resistance to osimertinib limits its clinical utility, and there is a lack of effective countermeasures. Here, we established osimertinib-resistant cell lines and performed drug library screening. This screening identified ivacaftor, a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator, as a synergistic enhancer of osimertinib-induced anti-tumor activity both in vitro and in vivo. Mechanistically, ivacaftor facilitated the colocalization of CFTR and PTEN on the plasma membrane to promote the function of PTEN, subsequently inhibiting the PI3K/AKT signaling pathway and suppressing tumor growth. In summary, our study suggests that activating CFTR enhances osimertinib-induced anti-tumor activity by regulating the PTEN-AKT axis. Furthermore, ivacaftor and osimertinib constitute a potential combination strategy for treating osimertinib-resistant EGFR-mutated NSCLC patients.

Myocardial dysfunction is a decisive factor of death in septic patients. Cyclophilin F (PPIF) is a major component of the mitochondrial permeability transition pore (mPTP) and acts as a critical mPTP sensitizer triggering mPTP opening. In sepsis, decreased NAD⁺ impairs Sirtuin 3 function, which may prevent PPIF de-acetylation. Repletion of NAD⁺ with nicotinamide mononucleotide (NMN) reduces myocardial dysfunction in septic mice. In addition, administration of the mPTP inhibitor cyclosporine-A attenuated sepsis-induced myocardial dysfunction, and deletion of PPIF reduced lung and liver injuries in sepsis, leading to increased survival. It is plausible that NAD⁺ repletion with NMN may prevent mPTP opening in protecting septic hearts through PPIF de-acetylation and/or inhibition of mitochondrial ROS-mediated PPIF oxidation. In this study we investigated how NMN alleviated myocardial dysfunction in septic mice. Sepsis was induced in mice by injection of LPS (4 mg/kg, i.p.). Then mice received NMN (500 mg/kg, i.p.) or mito-TEMPO (0.7 mg/kg, i.p.) right after LPS injection, and subjected to echocardiography for assessing myocardial function. At the end of experiment, the heart tissues and sera were collected for analyses. In vitro experiments were conducted in neonatal mouse cardiomyocytes treated with LPS (1 µg/mL) in the presence of NMN (500 µmol/L) or mito-TEMPO (25 nmol/L). We showed that LPS treatment markedly increased mitochondrial ROS production and induced lysosomal dysfunction and aberrant autophagy in cardiomyocytes and mouse hearts, leading to inflammatory responses and myocardial injury and dysfunction in septic mice. NMN administration attenuated LPS-induced deteriorative effects. Selective inhibition of mitochondrial superoxide production with mito-TEMPO attenuated lysosomal dysfunction and aberrant autophagy in septic mouse hearts. Notably, LPS treatment significantly increased acetylation and oxidation of PPIF, which was prevented by NMN in mouse hearts. Knockdown of PPIF replicated the beneficial effects of NMN or mito-TEMPO on ROS production, lysosomal dysfunction, aberrant autophagy, and myocardial injury/dysfunction in sepsis. In addition, administration of NMN abrogated LPS-induced ATP5A1 acetylation and increased ATP5A1 protein levels and ATP production in septic mouse hearts. This study demonstrates that NMN modulates the interplay of mitochondrial ROS and PPIF in maintaining normal lysosomal function and autophagy and protecting ATP5A1 and ATP production during sepsis.

Delta like non-canonical Notch ligand 1 (DLK1), as a member of epidermal growth factor-like family, plays a critical role in somatic growth, tissue development and possibly tissue renewal. Though previous studies had indicated that DLK1 contributed to adipogenesis and myogenesis, it's still controversial whether DLK1 affects angiogenesis and how it interacts with Notch signaling with numerous conflicting reports from different models. Based on our preliminary finding that DLK1 expression was up-regulated in mice ischemic gastrocnemius and in the border zone of infarcted myocardium, we administered either recombinant DLK1 (rDLK1) or PBS in C57BL/6 mice after establishment of hindlimb ischemia (HLI) and myocardial infarction (MI), respectively. Exogenous rDLK1 administration significantly improved both blood perfusion of mice ischemic hindlimbs and muscle motor function on the 3rd, 7th day after HLI, by promoting neovascularization. Similar effect on neovascularization was verified in mice on the 28th day after MI as well as improvement of cardiac failure. Correspondingly, the number of CD34⁺KDR⁺ cells, indicated as endothelial progenitor cells (EPCs), was significantly in mice ischemic gastrocnemius by rDLK1 administration, which was abrogated by DAPT as the specific inhibitor of Notch intracellular domain (NICD). Furthermore, bone marrow mononuclear cells were obtained from C57BL/6 mice and differentiated to EPCs ex vivo. Incubation with rDLK1 triggered Notch1 mRNA and NICD protein expressions in EPCs as exposed to hypoxia and serum deprivation, promoting EPCs proliferation, migration, anti-apoptosis and tube formation. Otherwise, rDLK1 incubation significantly decreased intracellular and mitochondrial reactive oxygen species, increased ATP content and mitochondrial membrane potential, downregulated short isoform of OPA-1 expression whereas upregulated mitofusin (-1, -2) expression in EPCs by Notch1 signaling, which were all abrogated by DAPT. In summary, the present study unveils the pro-angiogenesis and its mechanism of rDLK1 through activation of Notch1 signaling in endothelial progenitor cells.

Triple-negative breast cancer (TNBC) is incurable and prone to widespread metastasis. Therefore, identification of key targets for TNBC progression is urgently needed. Our previous study revealed that isotoosendanin (ITSN) reduced TNBC metastasis by targeting TGFβR1. ITSN is currently used as an effective chemical probe to further discover the key molecules involved in TNBC metastasis downstream of TGFβR1. The results showed that GOT2 was the gene downstream of Smad2/3 and that ITSN decreased GOT2 expression by abrogating the activation of the TGF-β-Smad2/3 signaling pathway through directly binding to TGFβR1. GOT2 was highly expressed in TNBC, and its knockdown decreased TNBC metastasis. However, GOT2 overexpression reversed the inhibitory effect of ITSN on TNBC metastasis both in vitro and in vivo. GOT2 interacted with MYH9 and hindered its binding to the E3 ubiquitin ligase STUB1, thereby reducing MYH9 ubiquitination and degradation. Moreover, GOT2 also enhanced the translocation of MYH9 to mitochondria and thus induced DRP1 phosphorylation, thereby promoting mitochondrial fission and lamellipodia formation in TNBC cells. ITSN-mediated inhibition of mitochondrial fission and lamellipodia formation was associated with reduced GOT2 expression. In conclusion, ITSN prevented MYH9-regulated mitochondrial fission and lamellipodia formation in TNBC cells by enhancing MYH9 protein degradation through a reduction in GOT2 expression, thus contributing to its inhibition of TNBC metastasis.

Sjogren's syndrome (SS) is a chronic, progressive autoimmune disorder characterized by gland fibrosis. We previously found a close correlation between gland fibrosis and the expression of G protein-coupled receptor kinase 2 (GRK2). In this study we explored the pathological and therapeutic significance of GRK2 in SS. Submandibular gland (SMG) antigen-induced SS mouse model was established in WT and GRK2^+/- mice. We showed that the expression levels of GRK2 were significantly up-regulated in glandular tissue and positively correlated with fibrotic morphology in SS patients and mice. Hemizygous knockout of GRK2 significantly inhibited the gland fibrosis. In mouse salivary gland epithelial cells (SGECs), we demonstrated that GRK2 interacted with Smad2/3 to positively regulate the activation of TGF-β-Smad signaling with a TGF-β-GRK2 positive feedback loop contributing to gland fibrosis. Hemizygous knockout of GRK2 attenuated TGF-β-induced collagen I production in SGECs in vitro and hindered gland fibrosis in murine SS though preventing Smad2/3 nuclear translocation. Around 28 days post immunization with SMG antigen, WT SS mice were treated with a specific GRK2 inhibitor paroxetine (Par, 5 mg·kg^-1·d^-1, i.g. for 19 days). We found that Par administration significantly attenuated gland fibrosis and alleviated the progression of SS in mice. We conclude that genetic knockdown or pharmacological inhibition of GRK2 significantly attenuates gland fibrosis and alleviates the progression of SS. GRK2 binds to Smad2/3 and positively regulates the activation of TGF-β-Smad signaling. A TGF-β-GRK2 positive feedback loop contributes to gland fibrosis. Our research points out that GRK2 could be a promising therapeutic target for treating SS.