Acta Pharmacologica Sinica最新文献

The pathological hallmarks of various neurodegenerative diseases including Parkinson's disease and Alzheimer's disease prominently feature the accumulation of misfolded proteins and neuroinflammation. Chaperone-mediated autophagy (CMA) has emerged as a distinct autophagic process that coordinates the lysosomal degradation of specific proteins bearing the pentapeptide motif Lys-Phe-Glu-Arg-Gln (KFERQ), a recognition target for the cytosolic chaperone HSC70. Beyond its role in protein quality control, recent research underscores the intimate interplay between CMA and immune regulation in neurodegeneration. In this review, we illuminate the molecular mechanisms and regulatory pathways governing CMA. We further discuss the potential roles of CMA in maintaining neuronal proteostasis and modulating neuroinflammation mediated by glial cells. Finally, we summarize the recent advancements in CMA modulators, emphasizing the significance of activating CMA for the therapeutic intervention in neurodegenerative diseases.

Metabolic-associated liver disease is a growing public health crisis, with phenotypes from fatty liver to steatohepatitis, previously known as NASH (Non-Alcoholic SteatoHepatitis) and currently rebranded as MASH (Metabolic dysfunction-Associated SteatoHepatitis). Dysfunction in liver metabolism can progress to liver fibrosis, end stage cirrhosis and death. MASH (NASH) is associated with an increased risk of cardiovascular disease, elevation in serum lipids and Type 2 Diabetes Mellitus. There is now a US-approved drug to treat patients with NASH (MASH) under the FDA Accelerated Approval Pathway, which requires follow-up outcome studies to confirm clinical benefit or risk drug withdrawal by the agency. Despite extra-hepatic factors that contribute to MASH and complicate clinical trial design, reorganization of the FDA drug premarket review divisions, improvements to agency policies and procedures, as well as updates to the US Food, Drug & Cosmetic Act (FD&C Act) upon which FDA regulation is based, have provided new agency tools that facilitated such a drug approval to address the profound unmet medical need for patients with this metabolic-based liver disease. There is reason for hope that continued evolution of the regulatory process will lead to additional drug approvals, as well as the ability for clinical trial endpoints studying MASH treatments to include both liver-based and traditional metabolic measures, independent of the specific FDA review division. This initial NASH/MASH FDA approval has also opened the door for initiation of Combination Clinical Trials, where the approved drug is paired with an experimental drug with a different mechanism of action, to increase overall efficacy and potentially minimize risks. It is envisioned that future treatment of NASH/MASH will mirror what is currently observed with Type 2 Diabetes Mellitus practice patterns, where multiple drugs with different mechanisms of actions are used to optimize treatment benefit/risk in the selected patient populations.

RAS is the most frequently mutated oncoprotein for cancer driving. Understanding of RAS biology and discovery of druggable lynchpins in RAS pathway is a prerequisite for targeted therapy of RAS-mutant cancers. The recent identification of KRAS^G12C inhibitor breaks the "undruggable" curse on RAS and has changed the therapy paradigm of KRAS-mutant cancers. However, KRAS mutations, let alone KRAS^G12C mutation, account for only part of RAS-mutated cancers. Targeted therapies for cancers harboring other RAS mutations remain the urgent need. In this study we explored the pivotal regulatory molecules that allow for broad inhibition of RAS mutants. By comparing the expression levels of nucleotide pyrophosphatase (NPPS) in a panel of cell lines and the functional consequence of increased NPPS expression in RAS-mutant cells, we demonstrated that cancer cells with various kinds of RAS mutations depended on NPPS for growth and survival, and that this dependence conferred a vulnerability of RAS-mutant cancer to treatment of NPPS inhibition. RAS-mutant cells, compared with RAS-wildtype cells, bored and required an upregulation of NPPS. Transcriptomics and metabolomics analyses revealed a NPPS-dependent hyperglycolysis in RAS-mutant cells. We demonstrated that NPPS promoted glucose-derived glycolytic intermediates in RAS-mutant cells by enhancing its interaction with hexokinase 1 (HK1), the enzyme catalyzing the first committed step of glycolysis. Pharmacological inhibition of NPPS-HK1 axis using NPPS inhibitor Enpp-1-IN-1 or HK1 inhibitor 2-deoxyglucose (2-DG), or genetic interfere with NPPS suppressed RAS-mutant cancers in vitro and in vivo. In conclusion, this study reveals an unrecognized mechanism and druggable lynchpin for modulation of pan-mutant-RAS pathway, proposing a new potential therapeutic approach for treating RAS-mutant cancers.

The Smad transcription factors are well known for their role at the core of transforming growth factor-β (TGF-β) signalling. However, recent evidence shows that the Smad transcription factors play a vital role downstream of other classes of receptors including G protein-coupled receptors (GPCR). The versatility of Smad transcription factors originated from the two regions that can be differently activated by the TGF-β receptor superfamily or through the recruitment of intracellular kinases stimulated by other receptors classes such as GPCRs. The classic GPCR signalling cascade is further expanded to conditional adoption of the Smad transcription factor under the stimulation of Akt, demonstrating the unique involvement of the Smad transcription factor in GPCR signalling pathways in disease environments. In this review, we provide a summary of the signalling pathways of the Smad transcription factors as an important downstream mediator of GPCRs, presenting exciting opportunities for discovering new therapeutic targets for diseases.

Carboxylesterase 2 (CES2) is expressed mainly in liver and intestine, but most abundantly in intestine. It hydrolyzes carboxylester, thioester, and amide bonds in many exogenous and endogenous compounds, including lipids. CES2 therefore not only plays an important role in the metabolism of many (pro-)drugs, toxins and pesticides, directly influencing pharmacology and toxicology in humans, but it is also involved in energy homeostasis, affecting lipid and glucose metabolism. In this study we investigated the pharmacological and physiological functions of CES2. We constructed Ces2 cluster knockout mice lacking all eight Ces2 genes (Ces2^-/- strain) as well as humanized hepatic or intestinal CES2 transgenic strains in this Ces2^-/- background. We showed that oral availability and tissue disposition of capecitabine were drastically increased in Ces2^-/- mice, and tissue-specifically decreased by intestinal and hepatic human CES2 (hCES2) activity. The metabolism of the chemotherapeutic agent vinorelbine was strongly reduced in Ces2^-/- mice, but only marginally rescued by hCES2 expression. On the other hand, Ces2^-/- mice exhibited fatty liver, adipositis, hypercholesterolemia and diminished glucose tolerance and insulin sensitivity, but without body mass changes. Paradoxically, hepatic hCES2 expression rescued these metabolic phenotypes but increased liver size, adipose tissue mass and overall body weight, suggesting a "healthy" obesity phenotype. In contrast, intestinal hCES2 expression efficiently rescued all phenotypes, and even improved some parameters, including body weight, relative to the wild-type baseline values. Our results suggest that the induction of intestinal hCES2 may combat most, if not all, of the adverse effects of metabolic syndrome. These CES2 mouse models will provide powerful preclinical tools to enhance drug development, increase physiological insights, and explore potential solutions for metabolic syndrome-associated disorders.

Accumulating evidence shows that neuroinflammation substantially contributes to the pathology of depression, a severe psychiatric disease with an increasing prevalence worldwide. Although modulating microglial phenotypes is recognized as a promising therapeutic strategy, effective treatments are still lacking. Previous studies have shown that luteolin (LUT) has anti-inflammatory effects and confers benefits on chronic stress-induced depression. In this study, we investigated the molecular mechanisms by which LUT regulates the functional phenotypes of microglia in mice with depressive-like behaviors. Mice were exposed to chronic restraint stress (CRS) for 7 weeks, and were administered LUT (10, 30, 40 mg· kg^-1 ·day^-1, i.g.) in the last 4 weeks. We showed that LUT administration significantly ameliorated depressive-like behaviors and decreased hippocampal inflammation. LUT administration induced pro-inflammatory microglia to undergo anti-inflammatory arginase (Arg)-1⁺ phenotypic polarization, which was associated with its antidepressant effects. Furthermore, we showed that LUT concentration-dependently increased the expression of PPARγ in LPS + ATP-treated microglia and the hippocampus of CRS-exposed mice, promoting the subsequent inhibition of the NLRP3 inflammasome. Molecular dynamics (MD) simulation and microscale thermophoresis (MST) analysis confirmed a direct interaction between LUT and peroxisome proliferator-activated receptor gamma (PPARγ). By using the PPARγ antagonist GW9662, we demonstrated that LUT-driven protection, both in vivo and in vitro, resulted from targeting PPARγ. First, LUT-induced Arg-1⁺ microglia were no longer detected when PPARγ was blocked. Next, LUT-mediated inhibition of the NLRP3 inflammasome and downregulation of pro-inflammatory cytokine production were reversed by the inhibition of PPARγ. Finally, the protective effects of LUT, which attenuated the microglial engulfment of synapses and prevented apparent synapse loss in the hippocampus of CRS-exposed mice, were eliminated by blocking PPARγ. In conclusion, this study showed that LUT ameliorates CRS-induced depressive-like behaviors by promoting the Arg-1⁺ microglial phenotype through a PPARγ-dependent mechanism, thereby alleviating microglial pro-inflammatory responses and reversing microglial phagocytosis-mediated synapse loss.

The impairment of blood-brain barrier (BBB) integrity is the pathological basis of hemorrhage transformation and vasogenic edema following thrombolysis and endovascular therapy. There is no approved drug in the clinic to reduce BBB damage after acute ischemic stroke (AIS). Glial growth factor 2 (GGF2), a recombinant version of neuregulin-1β that can stimulates glial cell proliferation and differentiation, has been shown to alleviate free radical release from activated microglial cells. We previously found that activated microglia and proinflammatory factors could disrupt BBB after AIS. In this study we investigated the effects of GGF2 on AIS-induced BBB damage as well as the underlying mechanisms. Mouse middle cerebral artery occlusion model was established: mice received a 90-min ischemia and 22.5 h reperfusion (I/R), and were treated with GGF2 (2.5, 12.5, 50 ng/kg, i.v.) before the reperfusion. We showed that GGF2 treatment dose-dependently decreased I/R-induced BBB damage detected by Evans blue (EB) and immunoglobulin G (IgG) leakage, and tight junction protein occludin degradation. In addition, we found that GGF2 dose-dependently reversed AIS-induced upregulation of vesicular transcytosis increase, caveolin-1 (Cav-1) as well as downregulation of major facilitator superfamily domain containing 2a (Mfsd2a). Moreover, GGF2 decreased I/R-induced upregulation of PDZ and LIM domain protein 5 (Pdlim5), an adaptor protein that played an important role in BBB damage after AIS. In addition, GGF2 significantly alleviated I/R-induced reduction of YAP and TAZ, microglial cell activation and upregulation of inflammatory factors. Together, these results demonstrate that GGF2 treatment alleviates the I/R-compromised integrity of BBB by inhibiting Mfsd2a/Cav-1-mediated transcellular permeability and Pdlim5/YAP/TAZ-mediated paracellular permeability.

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have obvious advantages over MSC therapy. But the strong procoagulant properties of MSC-EVs pose a potential risk of thromboembolism, an issue that remains insufficiently explored. In this study, we systematically investigated the procoagulant activity of large EVs derived from human umbilical cord MSCs (UC-EVs) both in vitro and in vivo. UC-EVs were isolated from cell culture supernatants. Mice were injected with UC-EVs (0.125, 0.25, 0.5, 1, 2, 4 μg/g body weight) in 100 μL PBS via the tail vein. Behavior and mortality were monitored for 30 min after injection. We showed that these UC-EVs activated coagulation in a dose- and tissue factor-dependent manner. UC-EVs-induced coagulation in vitro could be inhibited by addition of tissue factor pathway inhibitor. Notably, intravenous administration of high doses of the UC-EVs (1 μg/g body weight or higher) led to rapid mortality due to multiple thrombus formations in lung tissue, platelets, and fibrinogen depletion, and prolonged prothrombin and activated partial thromboplastin times. Importantly, we demonstrated that pulmonary thromboembolism induced by the UC-EVs could be prevented by either reducing the infusion rate or by pre-injection of heparin, a known anticoagulant. In conclusion, this study elucidates the procoagulant characteristics and mechanisms of large UC-EVs, details the associated coagulation risk during intravenous delivery, sets a safe upper limit for intravenous dose, and offers effective strategies to prevent such mortal risks when high doses of large UC-EVs are needed for optimal therapeutic effects, with implications for the development and application of large UC-EV-based as well as other MSC-EV-based therapies.

Chromosome instability (CIN) and subsequent aneuploidy are prevalent in various human malignancies, influencing tumor progression such as metastases and relapses. Extensive studies demonstrate the development of chemoresistance in high-CIN tumors, which poses significant therapeutic challenges. Given the association of CIN with poorer prognosis and suppressed immune microenvironment observed in colorectal carcinoma (CRC), here we aimed to discover chemotherapeutic drugs exhibiting increased inhibition against high-CIN CRC cells. By using machine learning methods, we screened out two BCL-XL inhibitors Navitoclax and WEHI-539 as CIN-sensitive reagents in CRC. Subsequent analyses using a CIN-aneuploidy cell model confirmed the vulnerability of high-CIN CRC cells to these drugs. We further revealed the critical role of BCL-XL in the viability of high-CIN CRC cells. In addition, to ease the evaluation of CIN levels in clinic, we developed a three-gene signature as a CIN surrogate to predict prognosis, chemotherapeutic and immune responses in CRC samples. Our results demonstrate the potential value of CIN as a therapeutic target in CRC treatment and the importance of BCL-XL in regulating survival of high-CIN CRC cells, therefore representing a valuable attempt to translate a common trait of heterogeneous tumor cells into an effective therapeutic target.

Poly (ADP-ribose) polymerase 1 (PARP1) is a DNA-binding protein that is involved in various biological functions, including DNA damage repair and transcription regulation. It plays a crucial role in cisplatin resistance. Nevertheless, the exact regulatory pathways governing PARP1 have not yet been fully elucidated. In this study, we present evidence suggesting that the hepatitis B X-interacting protein (HBXIP) may exert regulatory control over PARP1. HBXIP functions as a transcriptional coactivator and is positively associated with PARP1 expression in tissues obtained from hepatoma patients in clinical settings, and its high expression promotes cisplatin resistance in hepatoma. We discovered that the oncogene HBXIP increases the level of PARP1 m⁶A modification by upregulating the RNA methyltransferase WTAP, leading to the accumulation of the PARP1 protein. In this process, on the one hand, HBXIP jointly activates the transcription factor ETV5, promoting the activation of the WTAP promoter and further facilitating the promotion of the m⁶A modification of PARP1 by WTAP methyltransferase, enhancing the RNA stability of PARP1. On the other hand, HBXIP can also jointly activate the transcription factor CEBPA, enhance the activity of the PARP1 promoter, and promote the upregulation of PARP1 expression, ultimately leading to enhanced DNA damage repair capability and promoting cisplatin resistance in hepatoma. Notably, aspirin inhibits HBXIP, thereby reducing the expression of PARP1. Overall, our research revealed a novel mechanism for increasing PARP1 abundance, and aspirin therapy could overcome cisplatin resistance in hepatoma.