Type 2 diabetes development has been associated with islet amyloid polypeptide (IAPP) fibrillation. IAPP fibrils have various deleterious effects, such as oxidative stress and disruption of cellular membrane integrity, resulting in pancreatic β-cell toxicity. Rutin, a plant polyphenol, possesses promising cytoprotective effects as a fibrillation inhibitor. Similarly, bioactive peptides have been identified as potential inhibitors to IAPP fibrillation. In this study, the effect of peptide/polyphenol mixtures consisting of rutin and each peptide, TNGQ, MANT, and YMSV, on anti-fibrillation activity and cellular response was elucidated. Results indicated a 54.7-75.1 % decrease in thioflavin T fluorescence, confirming anti-fibrillation activity. The combination decreased the average particle diameters of IAPP more than the single inhibitors, suggesting a combined effect of peptide/rutin mixtures in enhancing anti-fibrillation activity. IAPP fibrillation-induced rat insulinoma RIN-m cell death was minimized in the presence of the peptide/rutin mixture, but the activity was lower relative to rutin alone, suggesting a non-additive effect of the mixtures. Transmission electron microscopy showed a near-complete inhibition of IAPP fibrillation by TNGQ/rutin mixtures, which translated to a decreased production of membrane-bound IAPP oligomers in RIN-m cells based on immunofluorescence staining. Additionally, TNGQ/rutin mixtures significantly decreased reactive oxygen species production by 30 %, higher than the effects of single inhibitors, but no effect was observed on glucose-stimulated insulin secretion. The results demonstrate the potential of multifunctional compounds as dual inhibitor systems in controlling IAPP fibrillation and provide insight into the implications of peptide/polyphenol mixtures towards the rational development of novel anti-diabetic nutraceutical combinations.

Many pathogens establish a successful infection by evading the host complement system, an essential arm of innate immunity. Pathogenic Leptospira is reported to escape complement-mediated killing by recruiting the host complement regulators by lipoproteins or outer surface proteins. One of the outer surface proteins, Leptospiral complement regulator-acquiring protein A (LcpA), is known to recruit complement regulators, C4b-binding protein (C4BP), and Factor H (FH) on the bacterial surface. Mapping of interacting domains from C4BP and FH with the LcpA has already been reported. However, the region or structural part of the LcpA mediating the interaction is not known yet. Here, we report cloning, expression, refolding and purification of recombinant LcpA from an inclusion body of E. coli heterologous expression system. We also demonstrate the biophysical characterization of recombinant LcpA and reveal its secondary structure contents. Moreover, the protein displays a moderate thermostability. The change of intrinsic fluorescence and CD spectra demonstrate a change in the secondary structure of protein due to binding with Zn ions. Molecular docking of LcpA with the complement regulators displays important interface residues from both the individual counterparts. Molecular dynamic simulation analysis demonstrates the stability of interactions between LcpA and C4BP. In our understanding, this is the first report on the large-scale purification of LcpA through refolding experiments and biophysical characterization of LcpA. This study may provide additional information on the structural basis of binding with the complement regulators.

The incidence rate of pancreatic cancer, a fatal illness with a meager 5-year survival rate, has been on the rise in recent times. When individuals accumulate excessive amounts of adipose tissue, the adipose organ becomes dysfunctional due to alterations in the adipose tissue microenvironment associated with inflammation and metabolism. This phenomenon may potentially contribute to the aberrant accumulation of fat that initiates pancreatic carcinogenesis, thereby influencing the disease's progression, resistance to treatment, and metastasis. This review presents a summary of the impact of pancreatic steatosis, visceral fat, cancer-associated adipocytes and lipid diets on the advancement of pancreatic cancer, as well as the reciprocal effects of pancreatic cancer on adipose tissue. Understanding the molecular mechanisms underlying the relationship between dysfunctional adipose tissue and pancreatic cancer better may lead to the discovery of new therapeutic targets for the disease's prevention and individualized treatment. This is especially important given the rising global incidence of obesity, which will improve the pancreatic cancer treatment options that are currently insufficient.

Isolated enzymes serve as advantageous platforms for the fabrication of nanomaterials. The objective of this study was to fabricate silver nanoparticles (AgNPs) incorporated with Trametes versicolor laccase and evaluate their diverse biological properties. The AgNPs fabricated through laccase-mediated methods were characterized using various characterization techniques including UV-visible (UV-vis) spectroscopy, Energy-dispersive X-ray (EDX) spectroscopy, Dynamic light scattering (DLS) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and Field emission scanning electron microscopy (FE-SEM). The results showed that the laccase-incorporated AgNPs were spherical in shape with a Z-average diameter of 19.40 nm and a zeta potential of -19.2 mV. The AgNPs exhibited significant dose-dependent in vitro α-amylase, urease, and DPPH free radical inhibitory activities, with maximum inhibitions of 83.49 ± 1.06 %, 68.95 ± 3.60 %, and 67.36 ± 3.40 %, respectively, at a concentration of 1000 μg mL. Furthermore, the intrinsic pathway-mediated anticoagulant activity of the fabricated AgNPs was confirmed through the activated partial thromboplastin time (aPTT) assay, which serves as a global coagulation assay. Additionally, the laccase-incorporated AgNPs demonstrated antibacterial properties against both standard gram-positive strains of Staphylococcus epidermidis and Streptococcus mutans, with minimum inhibitory concentration (MIC) values of 2 and 4 μg mL, and minimum bactericidal concentration (MBC) values of 16 and 16 μg mL, respectively. The dose-dependent antibacterial performance of the AgNPs against both bacterial populations was also confirmed through flow cytometry. Moreover, the AgNPs exhibited 61.53 ± 3.17 % and 63.03 ± 1.44 % biofilm degradation against S. epidermidis and S. mutans, respectively, at the maximum tested concentration (20∗MIC).

Preeclampsia (PE) is a complex multi-organ disorder characterized by systemic inflammation, endothelial dysfunction, and vasoconstriction, which manifests as hypertension, with or without proteinuria. Effective preventive strategies for PE are currently lacking in clinical practice, leading to significant morbidity and mortality among mothers and newborns.

Although natural killer (NK) cell responses to tumor and viral infection have been studied, the mechanisms underlying NK cell homeostasis in vivo remain unclear. In this study, we demonstrate the pharmacological action of cytostatin, a protein phosphatase 2A (PP2A) specific inhibitor (PP2Ai), on NK cells in regulating NK cell homeostasis in the peripheral tissues. We found that PP2Ai treatment decreased NK cell percentages in the bone marrow and secondary lymphoid tissues while increasing NK cell percentages in peripheral tissues such as the lung and liver. In the peripheral tissues of PP2Ai-treated mice, Ki-67 expression and BrdU uptake in NK cells were upregulated, and an initial increase in the pre-mature CD11bCD27 NK subset was observed, followed by an increase in the terminally differentiated mature CD11bCD27 NK subset. In addition, bone marrow Ki-67 NK cells predominantly expressed CX3CR1 in the PP2Ai-treated mice and were further mobilized to the peripheral tissues. Among various target molecules of PP2A, we found that the upregulation of c-Myc pathway and its phosphorylation, along with its downstream cyclin E expression and G1/S cell cycle transition in PP2Ai-treated mice NK cells. Our results suggest that PP2Ai modulates NK cell proliferation through c-Myc and cyclin E, leading to their maturation and trafficking from the bone marrow to the peripheral tissues.

Regulated intramembrane proteolysis (RIP) is a fundamentally conserved mechanism involving sequential cleavage by a membrane-bound Site-1 protease (S1P) and a transmembrane Site-2 protease (S2P). In the opportunistic pathogen Pseudomonas aeruginosa, the alternate sigma factor σ activates alginate production and in turn is regulated by the MucABCD system. The anti-sigma factor MucA, which inhibits σ, is sequentially cleaved via RIP by AlgW (S1P) and MucP (S2P) respectively. In this study, we report high-resolution crystal structures of the MucP PDZ1 and PDZ2 domains. Structural and binding analysis confirms that MucP PDZ2 recognizes the carboxy-terminal Ala136 residue of MucA following Site-1 cleavage by AlgW, while the peptide binding groove of PDZ1 is obstructed by a short α-helix. A structure of MucP PDZ2 with bound MucA peptide shows how PDZ2 binds the newly exposed carboxyl terminus of MucA following AlgW cleavage. The ability of a ΔmucP strain of P. aeruginosa to form biofilms was reduced to a similar extent as a ΔalgW strain. This work paves the way for further studies of MucP and other PDZ-containing S2Ps in regulated intramembrane proteolysis.

Methanogens, which are found exclusively in the Archaea domain of life, have the potential to help solve future energy challenges by producing methane. As a result, their metabolism has attracted significant attention in recent years. Despite being unable to grow on sugars, they store glycogen, which raises intriguing questions about the role of this polymer in methanogen metabolism and the signals that trigger its degradation when methanogenic substrates are not available. Here, we examined genomic databases to identify the enzymes responsible for glycogen synthesis and degradation in methanogens and explored the critical role of glycogen when nutrients and methanogenic substrates are scarce. Additionally, we analyzed the metabolic pathways involved in glycogen metabolism and their connection to the various types of methanogenesis exhibited by these organisms. Potential regulatory steps are proposed based on the reported effectors. Also, by employing the Alphafold3 server, the structural location of these sites in the enzyme structure was predicted, highlighting the advantages and limitations of this tool. Analysis of the allosteric effectors involved in this regulation suggests that energy charge may be the signal that triggers the metabolic switch from gluconeogenesis and glycogen storage to glycolysis and methanogenesis.

Protein inhibition via the traditional drug-designing approach has been shown to be an effective method for developing numerous small-molecule-based therapeutics. In the last decade, small inhibitors-guided protein degradation has arisen as an alternative method with the potential to fulfill the drug requirement for undruggable targets. Focal adhesion kinase (FAK) is a crucial modulator of the growth and spread of tumors, apart from it also acts as a scaffold for signaling of other proteins. FAK inhibitors have thus far had unsatisfactory results in clinical trials for cancer applications. Unlike prior attempts to control FAK expression, which were restricted to kinase domain inhibition with limited success in clinical research, protein degradation has the potential to concurrently disrupt FAK's kinase and scaffolding function. Recently, several FAK degraders were reported based on FAK Type I inhibitors using complex chemical synthesis approaches. Interestingly, recently a ternary complex was published revealing the binding mode of the FAK-PROTAC-E3 complex. This complex opens an avenue for the development of rational PROTAC design against FAK protein. Therefore, in the present study, we selected the most active Type I FAK inhibitor GSK2256098. The binding mode of the inhibitor prompted us to identify the most suitable analog for PROTAC design. We have identified a high-affinity analog that is suitable for PTOTAC design through the application of molecular docking (MD) and molecular dynamics simulations (MDS). Further based on the ternary FAK-PROTAC-E3 complex we build a binary complex FAK-Hit-E3-VHL between both proteins. Using the structure-based approach ten different potential FAK PROTACs candidates were designed. The stability of the complexes was analyzed using MDS and binding free energies were used to predict the binding affinity. Finally, based on desirable intermolecular interactions with the target and E3 ligase ProTAC4 was selected as the best candidate when compared with known FAK PROTAC GSK215.

Human genes have numerous copy number variations (CNVs) and single-nucleotide polymorphisms (SNPs) that control most of the body's core functions. On average, 12-16 % of human genes have CNVs, and a single gene can have a few hundred to several thousand SNPs. Numerous genome-wide association studies (GWAS) have shown that CNVs and SNPs can coexist in certain genomic regions, amplifying their effects on gene expression and regulation and disease susceptibility. Researchers initially categorized CNVs and SNPs into two types: homozygous and heterozygous. However, copy numbers were soon found to have a much wider range, underscoring their significance in certain diseases and microbial interactions. Because of the significant impact of CNVs and SNPs, research groups worldwide have eagerly sought effective methods for detecting both simultaneously. Despite yielding some minor results, these simultaneous counting methods have failed to meet expectations, leaving researchers to measure CNVs and SNPs separately. To overcome these limitations, we developed a novel approach by combining primers designed using the STexS method with matching probes used in the STexS II method. This method successfully detected both CNVs and SNPs in CYP2A6 and CYP2A7 using a single quantitative polymerase chain reaction. Once properly adjusted based on the three core principles, this new method markedly improved the time, cost-effectiveness, and overall accuracy of determining an individual's genetic status. Further testing of 100 human genomic DNA samples enabled calculations of the overall frequency of the [T] and [G] alleles of the CYP2A6 -48T > G SNP within an East Asian population yielded results that were highly congruent with those in a National Institutes of Health (NIH) database. This novel method will redefine genetic profiling and provide a means to successfully predict genetic characteristics and enhance personalized medicine by pinpointing appropriate individualized treatments.

Oxidative stress induced growth inhibitor 1 (OSGIN1) is a tumor protein p53 (TP53)-target gene involved in the oxidative stress response and promotes apoptosis. Here, we present the first evidence that OSGIN1 functions conversely by inhibiting ferroptosis, a distinct form of oxidative cell death driven by excessive lipid peroxidation. OSGIN1 expression is upregulated by pharmacological ferroptosis inducers in an NFE2 like BZIP transcription factor 2 (NFE2L2)-dependent manner, rather than through the TP53 pathway, in human pancreatic ductal adenocarcinoma (PDAC) cells. Genetic depletion of OSGIN1 or NFE2L2 similarly promotes ferroptosis, while re-expression of OSGIN1 rescues ferroptosis resistance in NFE2L2-knockout cells, both in vitro and in animal models. Mechanistically, immunoprecipitation combined with mass spectrometry revealed that OSGIN1 interacts with glutamate-cysteine ligase modifier subunit (GCLM), enhancing glutathione production and thereby mitigating oxidative stress. Additionally, OSGIN1 expression shows a positive correlation with NFE2L2 expression in pancreatic tumors, which is linked to poorer prognosis in PDAC patients. Collectively, these findings establish a novel defense mechanism that regulates ferroptosis and may influence tumor suppression in PDAC.

It is believed that oncolytic viruses (OVs) exert both direct anti-tumor effects by intratumoral injection as well as indirect anti-tumor effects by activating systemic immunity. In phase III clinical trials, OV and anti-programmed cell death-1 (aPD-1) antibody combination therapy showed no significant differences in overall survival and progression-free survival in patients with unresectable advanced melanoma. In the study, OVs can exert only indirect anti-tumor effects in non-injected, systemic lesions. If the tumor is at a stage where both direct and indirect anti-tumor effects of OVs can be expected, OVs may further enhance the therapeutic effect, in addition to the clinically expected therapeutic effect. Therefore, we investigated whether canerpaturev (C-REV) and aPD-1 antibody combination therapy suppresses tumor progression in a murine melanoma model. Our findings showed that the C-REV and aPD-1 antibody combination therapy suppressed tumor progression in a murine melanoma model. The combination therapy stimulated systemic immunity in lymphoid tissues by activating helper T cells and B cells to enhance adaptive and humoral immunity, as well as by increasing effector/memory T cell fractions. Synergistically enhanced systemic anti-tumor effects suppressed lymph node and lung metastases. These findings suggest that direct anti-tumor effects by infecting and destroying cancer cells from within and indirect anti-tumor effects enhanced by the combination therapy worked simultaneously to suppress tumor progression. Our results may provide evidence to support the usefulness of OV and aPD-1 antibody combination therapy as a neoadjuvant therapy in the surgical treatment of melanoma.

Pentosidine (PEN), an advanced glycation end product (AGE), is associated with various age-related diseases and schizophrenia. This study aimed to identify the natural compounds that inhibit PEN synthesis from glucuronic acid using an in vitro system. A screening of 93 natural compounds revealed 47 that reduced PEN synthesis by > 50 %, with eight inhibiting it by > 80 %. The top five inhibitors were anthocyanins, with petunidin chloride showing the strongest effect, inhibiting PEN synthesis by approximately 90 %. These compounds directly inhibited PEN synthesis without degrading or capturing the synthesized PEN. Petunidin chloride had an IC value approximately 85 times lower than that of pyridoxamine, an AGE inhibitor. A correlation between the antioxidant capacity of the compounds and their PEN-inhibitory effects was observed, suggesting that antioxidant properties may contribute to the inhibition mechanism. This study provides potential new therapeutic strategies for diseases associated with PEN accumulation, including schizophrenia, and highlights the potential of anthocyanins in the development of safer preventive interventions.

Metabolic diseases may be prevented by reducing carbohydrate intake and replacing plant-based diets with animal-based ones low in carbohydrates but high in protein, fat, and iron. While the effects of sugars on metabolic diseases are well-known, the role of iron remains unclear. This study aimed to explore the effects of a high-fat high-iron animal diet on body metabolism in mice. Micro-PET imaging was used to assess 18-F-labelled glucose uptake in BAT, and the morphology, respiratory function, and oxidative stress of BAT mitochondria were examined. The underlying mechanisms were elucidated by analyzing the expression of UCP-1, PGC-1α and PPARα. The high-iron high-fat diet increased appetite, impaired glucose tolerance, and reduced insulin sensitivity. Additionally, the high-iron diet promoted gluconeogenesis only in the absence of high-fat levels. Both high-iron and high-fat diets suppressed BAT activity, increased mitochondrial oxidative stress, decreased mitochondrial respiratory function, and lowered thermogenic gene expression. Weight loss strategies focusing solely on reducing carbohydrates and increasing animal foods, like ketogenic diets, may have long-term detrimental effects on metabolic health. Prioritizing dietary diversity and monitoring overall caloric intake is advisable for optimal outcomes.

CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) serves as an adaptive immune system in bacteria and archaea, offering a defense mechanism against invading genetic elements such as viruses (bacteriophages) and plasmids. Today, CRISPR has evolved into a powerful gene-editing technology that enables highly specific and rapid modifications of DNA within a genome. It has a broad range of applications across various fields, including medicine, agriculture, and fundamental research. One of the significant challenges facing this technology is the efficient transfer of CRISPR constructs into target cells for gene editing. There are several methods to deliver this system into target cells, which can be classified as viral and non-viral methods. Each of these approaches has its own advantages and disadvantages. Recently, the use of extracellular vesicles for delivery has garnered particular attention. Exosomes are nano-sized extracellular vesicles that have emerged as promising carriers for drug delivery due to their unique properties. These naturally occurring vesicles, typically ranging from 30 to 150 nm in diameter, facilitate intercellular communication by transferring bioactive molecules such as proteins, lipids, and nucleic acids between cells. Exosome therapy has surfaced as a promising strategy in regenerative medicine, utilizing small extracellular vesicles to deliver therapeutic molecules to target cells. One of the emerging options for transferring the CRISPR system is exosomes. The integration of these two advanced technologies holds significant potential for developing efficient and targeted gene editing and advancing precision medicine. In contemporary medicine, there is an increasing focus on personalized and targeted treatments that cater to the distinct genetic and molecular profiles of individual patients. The synergy of CRISPR technology and exosome therapy presents a remarkable opportunity to develop highly targeted and effective therapeutic strategies customized to individual patient requirements. This review article examines the potential of incorporating CRISPR technology within exosomes for precision therapeutic applications.

Hypoxia inducible factor 2α (HIF-2α) is a member of the basic helix-loop-helix(bHLH)-Per-Arnt-Sim (PAS) family of transcription factors. It is overexpressed in several cancers, associated with poor prognosis of the patients and resistance to treatment. Here, we study the residues 366-704 of the C-terminal end of human HIF-2α, which contains the N-transcriptional activation domain (NTAD), the oxygen-dependent degradation domain (ODD), and a part of the inhibitory domain (IH). An efficient protocol was developed to produce the 366-704 domain of human HIF-2α protein. Subsequently, we analyzed its biophysical characteristics using circular dichroism spectroscopy and size exclusion chromatography showing that the protein forms an antiparallel beta sheet conformation, and a computational model of the HIF-2α structure was produced. Our data offer new structural information for the unique biological properties of HIF-2α.

New phosphate-modified nucleic acid derivatives are of great significance in basic research and biomedical applications. We have recently developed a new class of phosphoramide benzoazole oligonucleotides (PABAOs). In this work, th properties of N-benzoxazole oligodeoxyribonucleotides have been thoroughly examined. We have demonstrated the convenient automated solid-phase synthesis of oligomers with a different number of modifications (up to six) at various positions. Optical properties, thermal stability, structure, and dynamics of PABAO/DNA complexes have been investigated. The N-benzoxazole-modified phosphate group is uncharged at neutral pH and has a pKa value of 8.52. Structural analysis performed by the CD spectroscopy and MD simulation indicate B-form of PABAO/DNA duplexes. The thermal stability of PABAO/DNA complexes bearing N-benzoxazole is reduced by 2.5-6.2° per modification compared to native duplexes at standard and near physiological buffer conditions. The performed study underlines a great potential of phosphoramide benzoazole oligonucleotides for basic research, applied sciences, and biotechnology.

Signal transducer and activator of transcription 3 (STAT3) is a multifactorial regulator involved in many biological responses. Alternative splicing of STAT3 pre-mRNA leads to an internal 50-nucleotide deletion of exon 23 selecting an alternative 3' acceptor site, resulting in the generation of two splicing isoforms, STAT3α and STAT3β. STAT3β lacks 55 amino acid-residue transactivation domain at the C-terminal of STAT3α replacing seven unique amino acids. Although STAT3β was originally thought to be a dominant negative isoform of STAT3α, accumulating evidence have shown that STAT3β possesses both its unique functions and those that overlap with STAT3α in fundamental cellular processes. However, much remains unknown about STAT3 pre-mRNA alternative splicing in determining the balance between STAT3 isoforms. In this study, we identified cis-regulatory elements and CUGBP2/ETR-3 as a novel trans-acting factor that regulates STAT3 alternative splicing. Our findings demonstrate that STAT3 splicing can be modulated by CUGBP2 via association with UG-rich elements of intron 22, providing a novel insight into the mechanism of STAT3 alternative splicing. CUGBP2 would be a crucial molecule regulating the balance of STAT3 isoform expression, thus targeting CUGBP2 and its recognition sequences in intron 22 of STAT3 might impact on various biological processes regulated by STAT3 signaling pathway.

The Phenotypic states of vascular smooth muscle cells (SMCs) are essential to understanding vascular pathophysiology. SMCs in vessels generally express a specific set of contractile proteins, but decreased contractile protein expression, indicating a phenotypic shift, is a hallmark of vascular diseases. Recent studies have suggested the relation of abnormally high wall shear stress (WSS) of approximately 20 Pa with the aortic disease pathogenesis. However, due to the lack of appropriate experimental models to assess SMC phenotypic states, the details of the phenotypic shift under high WSS conditions remain unclear. In this study, we developed a coculture model where vascular endothelial cells (ECs) were cocultured with SMCs expressing calponin 1, a contractile protein involved in the phenotypic shift of SMCs. We investigated the effects of a pathologically high WSS condition on the phenotypic states of SMCs. Increased calponin 1 expression was found upon exposure to 20 Pa WSS compared with a physiological 2 Pa condition, whereas the expression of another contractile protein, α-smooth muscle actin (αSMA) remained unchanged. Furthermore, the inhibition of EC-derived nitric oxide (NO), which is associated with endothelial dysfunction in vascular diseases, resulted in a trend of decreasing αSMA and Calponin 1 expression under 20 Pa WSS conditions compared with 2 Pa. Our findings suggest that EC-derived NO under pathologically high WSS conditions may impact the expression of contractile proteins implicated in aortic pathophysiology.

The multifunctional promyelocytic leukemia protein (PML) is involved in the regulation of various cellular processes in both physiological and pathological conditions. Specifically, PML is one of the inositol-1,4,5-trisphosphate receptors (IPRs) activity regulators and can influence Ca transport from the endoplasmic reticulum (ER) to mitochondria. In this work, the effects of PML knockout on calcium homeostasis in the cytosol, ER, and mitochondria of HeLa cells were studied upon stimulation with histamine, which induces Ca mobilization from the ER via IPRs. We utilized calcium indicators with different subcellular localizations, including synthetic dyes Fura-2 (cytosolic), Xrhod-5F (mitochondrial), and protein sensor R-CEPIAer (ER), as well as mitochondrial potential-sensitive probes Rh123 and TMRM. Our results show that PML knockout induced changes in HeLa cell and mitochondrial morphology, slightly decreased basal and integral Ca levels, enhanced mitochondrial Ca uptake from the cytoplasm, and maintained residual mitochondrial potential after depolarization. Additionally, it reduced the Ca pool in ER membranes not associated with histamine receptor activation and, consequently, IPRs. These findings suggest that changes in calcium ion transport due to PML knockout in HeLa cells affect mitochondrial activity.

The physiological actions of a gut hormone, glucagon-like peptide-1 (GLP-1), in Alzheimer's disease (AD) brain remain poorly understood, although GLP-1 receptor (GLP-1R) expression in this organ has been shown in several experimental studies. Therefore, we explored whether the GLP-1R signaling promotes the clearance of amyloid β (Aβ) (1-42) which is a core pathological hallmark of AD, focusing on the water channel protein aquaporin 4 (AQP4) localized to astrocyte endfeet perivascular membranes in intact brain. First, we confirmed that Glp1r mRNA is predominantly expressed at perivascular site of astrocytes in normal mouse cerebral cortex through in situ hybridization analysis. Next, we observed that 20-week subcutaneous administration of a GLP-1R agonist (GLP-1RA) liraglutide significantly reduced Aβ (1-42) accumulation in the cerebral cortex and improved spatial working memory in an AD mouse model, App mice. Furthermore, our current data revealed that the 4-week liraglutide treatment relocalized subcellular AQP4 in morphologically injured reactive astrocytes of App mice to the cell surface perivascular site through PKA-mediated AQP4 phosphorylation. Such translocation of phosphorylated AQP4 to astrocyte cell surface following incubation with liraglutide was observed also in the present in vitro study using the cell line in which AQP4 cDNA was introduced into immortalized human astrocyte. These results suggest that enhanced intracerebral GLP-1R signaling following peripheral administration of GLP-1RA restores AQP4 subcellular polarization in reactive astrocytes and would promote Aβ excretion possibly through increasing AQP4-mediated intracerebral water flux in the brain in AD.