G protein-coupled receptor-induced Akt activity in cellular proliferation and apoptosis

Targeting PI3K in cancer treatment: A comprehensive review with insights from clinical outcomes

The phosphoinositide 3-kinase (PI3K) pathway plays a crucial role in cancer, including cell growth, survival, metabolism, and metastasis. Its major role in tumor growth makes it a key target for cancer therapeutics, offering significant potential to slow tumor progression and enhance patient outcomes. Gain-of-function mutations, gene amplifications, and the loss of regulatory proteins like PTEN are frequently observed in malignancies, contributing to tumor development and resistance to conventional treatments such as chemotherapy and hormone therapy. As a result, PI3K inhibitors have received a lot of interest in cancer research. Several kinds of small-molecule PI3K inhibitors have been developed, including pan-PI3K inhibitors, isoform-specific inhibitors, and dual PI3K/mTOR inhibitors, each targeting a distinct component of the pathway. Some PI3K inhibitors such as idelalisib, copanlisib, duvelisib, alpelisib, and umbralisib have received FDA-approval, and are effective in the treatment of breast cancer and hematologic malignancies. Despite promising results in preclinical and clinical trials, the overall clinical success of PI3K inhibitors has been mixed. While some patients may get substantial advantages, a considerable number of them acquire resistance as a result of feedback activation of alternative pathways, adaptive tumor responses, and treatment-emergent mutations. The resistance mechanisms provide barriers to the sustained efficacy of PI3K-targeted treatments. This study reviews recent advancements in PI3K inhibitors, covering their clinical status, mechanism of action, resistance mechanisms, and strategies to overcome resistance.

Divergent roles of DRY and NPxxY motifs in selective activation of downstream signalling by the apelin receptor

G protein-coupled receptors (GPCRs) serve as critical communication hubs, translating a wide range of extracellular signals into intracellular responses that govern numerous physiological processes. In class-A GPCRs, conserved motifs mediate conformational changes of the active states of the receptor, and signal transduction is achieved by selectively binding to Gα proteins and/or adapter protein, arrestin. Apelin receptor (APJR) is a class-A GPCR that regulates a wide range of intracellular signalling cascades in response to apelin and elabela peptide ligands. Understanding how conserved motifs within APJR mediate activation and signal specificity remains unexplored. This study focuses on the functional roles of the DRY and NPxxY motifs within APJR by analyzing their impact on downstream signaling pathways across the receptor's conformational ensembles. Our findings provide compelling evidence that mutations within the conserved DRY and NPxxY motifs of APJR significantly alter its conformational preferences where modification of DRY motif leads to abrogation of G-protein coupling and mutation of NPxxY motif causing abolition of β-arrestin-2 recruitment. These observations shed light on the importance of these motifs in APJR activation and its potential for functional selectivity, highlighting the role of DRY/NPxxY as conformational switches of APJR signalling.

Old drug, new use: Recent advances for G-CSF

Granulocyte colony-stimulating factor (G-CSF), also known as colony-stimulating factor 3 (CSF3), is a proinflammatory cytokine that primarily stimulates the survival, proliferation, differentiation and function of neutrophil granulocyte progenitor cells and mature neutrophils. Over the past years, G-CSF has mainly been used to cure patients with neutropenia and as a part of chemotherapy to induct the remission for refractory/relapse leukemia. Recent studies showed that C-CSF can been used as condition regimens and as a part of preventive methods after allogeneic transplantation to improve the survival of patients and also has immunoregulation, and has promote or inhibit the proliferation of solid tumors. Therefore, in this review, we firstly describe the structure for G-CSF. Then its functions and mechanism were reviewed including the neutrophil mobilization, differentiation, migration, and inhibiting apoptosis of neutrophils, and its immunoregulation. Finally, the clinical applications were further discussed.

Age-Related Choroidal Involution Is Associated with the Senescence of Endothelial Progenitor Cells in the Choroid

Background: Choroidal involution is a common feature of age-related ischemic retinopathies such as age-related macular degeneration (AMD). It is now well recognized that endothelial progenitor cells (EPCs) are essential to endothelial repair processes and in maintaining vascular integrity. However, the contribution of EPCs and the role of senescence in age-related choroidal vascular degeneration remain to be investigated. In this study, we compared the senescent phenotype of EPCs in the choroid and performed whole-genome profiling of EPCs derived from young versus old rats. Methods and Results: We isolated and compared the retinas of young (6-weeks-old) and old (16-18-month-old) rats. The thickness of the choroid and outer nuclear layer (ONL), along with local quantification of CD34+ EPCs, was performed. Compared to young rats, older rats displayed a significant reduction in choroidal and ONL thickness associated with markedly fewer choroid-localized EPCs; this was attested by lower expression of several EPC markers (CXCR4, CD34, CD117, CD133, and KLF-2). Choroid and choroid-localized EPCs displayed abundant senescence as revealed by increased β-gal and P53 expression and decreased Lamin-B1 (immunostaining and RT-qPCR). Concordantly, choroidal cells and EPCs isolated from older rats were unable to form vascular networks ex vivo. To better understand the potential mechanisms associated with the dysfunctional EPCs linked to age-related choroidal involution, we performed whole-genome profiling (mRNA and miRNA) of EPCs derived from old and young rats using next-generation sequencing (NGS); 802 genes were significantly modulated in old vs. young EPCs, corresponding to ~2% of total genes expressed. Using a bioinformatic algorithm, the KEGG pathways suggested that these genes participate in the modulation of several key signaling processes including inflammation, G protein-coupled receptors, and hematopoietic cell lineages. Moreover, we identified 13 miRNAs involved in the regulation of immune system processes, cell cycle arrest and senescence, which are significantly modulated in EPCs from old rats compared to young ones. Conclusions: Our results suggest that age-related choroidal involution is associated with fewer EPCs, albeit displaying a senescence-like phenotype. One would be tempted to propose that biological modification of native EPCs (such as with senolytic agents) could potentially provide a new strategy to preserve the vascular integrity of the aged choroid, and evade progression to degenerative maculopathies.

Development and therapeutic perspectives of CXCR4 antagonists for disease therapy

Chemokine receptor 4 (CXCR4) is a subtype receptor protein of the GPCR family with a seven-transmembrane structure widely distributed in human tissues. CXCR4 is involved in diseases (e.g., HIV-1 infection), cancer proliferation and metastasis, inflammation signaling pathways, and leukemia, making it a promising drug target. Clinical trials on CXCR4 antagonists mainly focused on peptides and antibodies, with a few small molecule compounds, such as AMD11070 (2) and MSX-122 (3), showing promise in cancer treatment. This perspective discusses the structure-activity relationship (SAR) of CXCR4 and its role in diseases, mainly focusing on the SAR of CXCR4 antagonists. It also explores the standard structural features and target interactions of CXCR4 binding in different disease categories. Furthermore, it investigates various modification strategies to propose potential improvements in the effectiveness of CXCR4 drugs.

17-β-estradiol and phytoestrogens elicit NO production and vasodilatation through PI3K, PKA and EGF receptors pathways, evidencing functional selectivity

Endothelial cells express multiple receptors mediating estrogen responses; including the G protein-coupled estrogen receptor (GPER). Past studies on nitric oxide (NO) production elicited by estrogens raised the question whether 17-β-estradiol (E2) and natural phytoestrogens activate equivalent mechanisms. We hypothesized that E2 and phytoestrogens elicit NO production via coupling to distinct intracellular pathways signalling. To this aim, perfusion of E2 and phytoestrogens to the precontracted rat mesentery bed examined vasorelaxation, while fluorescence microscopy on primary endothelial cells cultures quantified single cell NO production determined following 4-amino-5-methylamino-2',7'-difluoroescein diacetate (DAF) incubation. Daidzein (DAI) and genistein (GEN) induced rapid vasodilatation associated to NO production. Multiple estrogen receptor activity was inferred based on the reduction of DAF-NO signals; G-36 (GPER antagonist) reduced 75 % of all estrogen responses, while fulvestrant (selective nuclear receptor antagonist) reduced significantly more the phytoestrogens responses than E2. The joint application of both antagonists abolished the E2 response but not the phytoestrogen-induced DAF-NO signals. Wortmannin or LY-294002 (PI3K inhibitors), reduced by 90% the E2-evoked signal while altering significantly less the DAI-induced response. In contrast, H-89 (PKA inhibitor), elicited a 23% reduction of the E2-induced signal while blocking 80% of the DAI-induced response. Desmethylxestospongin-B (IP3 receptor antagonist), decreased to equal extent the E2 or the DAI-induced signal. Epidermal growth factor (EGF) induced NO production, cell treatment with AG-1478, an EGF receptor kinase inhibitor reduced 90% DAI-induced response while only 53% the E2-induced signals; highlighting GPER induced EGF receptor trans-modulation. Receptor functional selectivity may explain distinct signalling pathways mediated by E2 and phytoestrogens.

The impact of volatile anesthetics and propofol on phosphatidylinositol 4,5-bisphosphate signaling

Phosphatidylinositol 4,5-bisphosphate (PIP2), as well as other anionic phospholipids, play a pivotal role in various cellular processes, including ion channel regulation, receptor trafficking, and intracellular signaling pathways. The binding of volatile anesthetics and propofol to PIP2 leads to alterations in PIP2-mediated signaling causing modulation of ion channels such as ɣ-aminobutyric acid type A (GABAA) receptors, voltage-gated calcium channels, and potassium channels through various mechanisms. Additionally, the interaction between anionic phospholipids and G protein-coupled receptors plays a critical role in various anesthetic pathways, with these anesthetic-induced changes impacting PIP2 levels which cause cascading effects on receptor trafficking, including GABAA receptor internalization. This comprehensive review of various mechanisms of interaction provides insights into the intricate interplay between PIP2 signaling and anesthetic-induced changes, shedding light on the molecular mechanisms underlying anesthesia.

Opportunities and challenges for the development of M1 muscarinic receptor positive allosteric modulators in the treatment for neurocognitive deficits

Targeting allosteric sites of M1 muscarinic acetylcholine receptors (M1 receptors) is a promising strategy to treat neurocognitive disorders, such as Alzheimer's disease and schizophrenia. Indeed, the last two decades have seen an impressive body of work focussing on the design and development of positive allosteric modulators (PAMs) for the M1 receptor. This has led to the identification of a structurally diverse range of highly selective M1 PAMs. In preclinical models, M1 PAMs have shown rescue of cognitive deficits and improvement of endpoints predictive of symptom domains of schizophrenia. Yet, to date only a few M1 PAMs have reached early-stage clinical trials, with many of them failing to progress further due to on-target mediated cholinergic adverse effects that have plagued the development of this class of ligand. This review covers the recent preclinical and clinical studies in the field of M1 receptor drug discovery for the treatment of Alzheimer's disease and schizophrenia, with a specific focus on M1 PAM, highlighting both the undoubted potential but also key challenges for the successful translation of M1 PAMs from bench-side to bedside. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.

Cardiomyocyte-specific overexpression of GPR22 ameliorates cardiac injury in mice with acute myocardial infarction

BACKGROUND

The activation of G protein-coupled receptors (GPCR) signaling by external stimuli has been implicated in inducing cardiac stress and stress responses. GPR22 is an orphan GPCR expressed in brains and hearts, while its expression level is associated with cardiovascular damage in diabetes. Previous studies have suggested a protective role of GPR22 in mechanical cardiac stress, as loss of its expression increases susceptibility to heart failure post-ventricular pressure overload. However, the involvement and underlying signaling of GPR22 in cardiac stress response to ischemic stress remains unexplored.

METHODS

In this study, we used cultured cells and a transgenic mouse model with cardiomyocyte-specific GPR22 overexpression to investigate the impact of ischemic stress on GPR22 expression and to elucidate its role in myocardial ischemic injury. Acute myocardial infarction (AMI) was induced by left coronary artery ligation in eight-week-old male GPR22 transgenic mice, followed by histopathological and biochemical examination four weeks post-AMI induction.

RESULTS

GPR22 expression in H9C2 and RL-14 cells, two cardiomyocyte cell lines, was decreased by cobalt chloride (CoCl2) treatment. Similarly, reduced expression of myocardial GPR22 was observed in mice with AMI. Histopathological examinations revealed a protective effect of GPR22 overexpression in attenuating myocardial infarction in mice with AMI. Furthermore, myocardial levels of Bcl-2 and activation of PI3K-Akt signaling were downregulated by ischemic stress and upregulated by GPR22 overexpression. Conversely, the expression levels of caspase-3 and phosphorylated ERK1/2 in the infarcted myocardium were downregulated with GPR22 overexpression.

CONCLUSION

Myocardial ischemic stress downregulates cardiac expression of GPR22, whereas overexpression of GPR22 in cardiomyocytes upregulates Akt signaling, downregulates ERK activation, and mitigates ischemia-induced myocardial injury.

CXCR4: From Signaling to Clinical Applications in Neuroendocrine Neoplasms

There are several well-described molecular mechanisms that influence cell growth and are related to the development of cancer. Chemokines constitute a fundamental element that is not only involved in local growth but also affects angiogenesis, tumor spread, and metastatic disease. Among them, the C-X-C motif chemokine ligand 12 (CXCL12) and its specific receptor the chemokine C-X-C motif receptor 4 (CXCR4) have been widely studied. The overexpression in cell membranes of CXCR4 has been shown to be associated with the development of different kinds of histological malignancies, such as adenocarcinomas, epidermoid carcinomas, mesenchymal tumors, or neuroendocrine neoplasms (NENs). The molecular synapsis between CXCL12 and CXCR4 leads to the interaction of G proteins and the activation of different intracellular signaling pathways in both gastroenteropancreatic (GEP) and bronchopulmonary (BP) NENs, conferring greater capacity for locoregional aggressiveness, the epithelial-mesenchymal transition (EMT), and the appearance of metastases. Therefore, it has been hypothesized as to how to design tools that target this receptor. The aim of this review is to focus on current knowledge of the relationship between CXCR4 and NENs, with a special emphasis on diagnostic and therapeutic molecular targets.

The Identification of a Novel Nucleomodulin MbovP467 of Mycoplasmopsis bovis and Its Potential Contribution in Pathogenesis

Mycoplasmopsis bovis is a causative agent of crucial diseases in both dairy and beef cattle leading to substantial economic losses. However, limited control measures for M. bovis-related diseases exist due to a lack of understanding about the virulence factors of this pathogen, a common challenge in mycoplasma research. Consequently, this study aimed to characterize a novel nucleomodulin as a virulence-related factor of M. bovis. Employing bioinformatic tools, we initially predicted MbovP467 to be a secreted protein with a nuclear localization signal based on SignalP scores and the cNLS (Nuclear Localization Signal) Mapper, respectively. Subsequently, the MbovP467 gene was synthesized and cloned into a pEGFP plasmid with EGFP labeling to obtain a recombinant plasmid (rpEGFP-MbovP467) and then was also cloned in pET-30a with a consideration for an Escherichia coli codon bias and expressed and purified for the production of polyclonal antibodies against the recombinant MbovP467 protein. Confocal microscopy and a Western blotting assay confirmed the nuclear location of MbovP467 in bovine macrophages (BoMacs). RNA-seq data revealed 220 up-regulated and 20 down-regulated genes in the rpEGFP-MbovP467-treated BoMac group compared to the control group (pEGFP). A GO- and KEGG-enrichment analysis identified associations with inflammatory responses, G protein-coupled receptor signaling pathways, nuclear receptor activity, sequence-specific DNA binding, the regulation of cell proliferation, IL-8, apoptotic processes, cell growth and death, the TNF signaling pathway, the NF-κB signaling pathway, pathways in cancer, and protein families of signaling and cellular processes among the differentially expressed up-regulated mRNAs. Further experiments, investigating cell viability and the inflammatory response, demonstrated that MbovP467 reduces BoMac cell viability and induces the mRNA expression of IL-1β, IL-6, IL-8, TNF-α, and apoptosis in BoMac cells. Further, MbovP467 increased the promoter activity of TNF-α. In conclusion, this study identified a new nucleomodulin, MbovP467, for M. bovis, which might have an important role in M. bovis pathogenesis.

The Role of Receptor-Ligand Interaction in Somatostatin Signaling Pathways: Implications for Neuroendocrine Tumors

Neuroendocrine tumors (NETs) arise from neuroendocrine cells and manifest in diverse organs. Key players in their regulation are somatostatin and its receptors (SSTR1-SSTR5). Understanding receptor-ligand interactions and signaling pathways is vital for elucidating their role in tumor development and therapeutic potential. This review highlights SSTR characteristics, localization, and expression in tissues, impacting physiological functions. Mechanisms of somatostatin and synthetic analogue binding to SSTRs, their selectivity, and their affinity were analyzed. Upon activation, somatostatin initiates intricate intracellular signaling, involving cAMP, PLC, and MAP kinases and influencing growth, differentiation, survival, and hormone secretion in NETs. This review explores SSTR expression in different tumor types, examining receptor activation effects on cancer cells. SSTRs' significance as therapeutic targets is discussed. Additionally, somatostatin and analogues' role in hormone secretion regulation, tumor growth, and survival is emphasized, presenting relevant therapeutic examples. In conclusion, this review advances the knowledge of receptor-ligand interactions and signaling pathways in somatostatin receptors, with potential for improved neuroendocrine tumor treatments.

GPR34 Knockdown Relieves Cognitive Deficits and Suppresses Neuroinflammation in Alzheimer's Disease via the ERK/NF-κB Signal

Alzheimer's disease (AD) is a serious neurodegenerative disease characterized by amyloid-β (Aβ) aggregation and neuroinflammation. G-protein-coupled receptor 34 (Gpr34) was found highly expressed in the hippocampus of APP/PS1 mice. However, its role in AD remains unclear. Herein, the role of Gpr34 as well as its molecular mechanism was explored. Data in GSE85162 were analyzed and the differently expressed genes in the hippocampus tissues of APP/PS1 mouse model of AD were subjected to GO, KEGG and GSEA enrichment analyses. APP/PS1 mice were used as an animal model of AD and the cognitive impairment was evaluated by a water maze test. The level of Gpr34 in hippocampus and BV-2 cells as well as the activation of ERK/NF-κB signal was determined by quantitative real-time PCR, western blot or immunofluorescence. Our results showed that, in BV-2 cells exposed to Aβ1-42, Gpr34 knockdown decreased the levels of TNF-α, IL-1β, IL-6 and iNOS and suppressed the activation of ERK/NF-κB signal. Moreover, the Gpr34-overexpression-induced activation of ERK/NF-κB signal and up-regulated levels of TNF-α, IL-1β, IL-6 and iNOS were abolished by FR180204, an ERK inhibitor. On the other hand, the in vivo study showed that Gpr34 knockdown ameliorated the cognitive impairment in APP/PS1 mice, decreased the levels of TNF-α, IL-1β and IL-6, the activation of microglia and ERK/NF-κB signal. In conclusion, Gpr34 knockdown relieved cognitive deficits in APP/PS1 mice and suppressed neuroinflammation and microglial activation, maybe via the ERK/NF-κB signal. It is indicated that the high level of Grp34 in hippocampus may contribute to the pathogenesis of AD.

Mechanism of action deconvolution of the small-molecule pathological tau aggregation inhibitor Anle138b

BACKGROUND

A key histopathological hallmark of Alzheimer's disease (AD) is the presence of neurofibrillary tangles of aggregated microtubule-associated protein tau in neurons. Anle138b is a small molecule which has previously shown efficacy in mice in reducing tau aggregates and rescuing AD disease phenotypes.

METHODS

In this work, we employed bioinformatics analysis-including pathway enrichment and causal reasoning-of an in vitro tauopathy model. The model consisted of cultured rat cortical neurons either unseeded or seeded with tau aggregates derived from human AD patients, both of which were treated with Anle138b to generate hypotheses for its mode of action. In parallel, we used a collection of human target prediction models to predict direct targets of Anle138b based on its chemical structure.

RESULTS

Combining the different approaches, we found evidence supporting the hypothesis that the action of Anle138b involves several processes which are key to AD progression, including cholesterol homeostasis and neuroinflammation. On the pathway level, we found significantly enriched pathways related to these two processes including those entitled "Superpathway of cholesterol biosynthesis" and "Granulocyte adhesion and diapedesis". With causal reasoning, we inferred differential activity of SREBF1/2 (involved in cholesterol regulation) and mediators of the inflammatory response such as NFKB1 and RELA. Notably, our findings were also observed in Anle138b-treated unseeded neurons, meaning that the inferred processes are independent of tau pathology and thus represent the direct action of the compound in the cellular system. Through structure-based ligand-target prediction, we predicted the intracellular cholesterol carrier NPC1 as well as NF-κB subunits as potential targets of Anle138b, with structurally similar compounds in the model training set known to target the same proteins.

CONCLUSIONS

This study has generated feasible hypotheses for the potential mechanism of action of Anle138b, which will enable the development of future molecular interventions aiming to reduce tau pathology in AD patients.

CXCL12 and CXCR4 as Novel Biomarkers in Uric Acid-Induced Inflammation and Patients with Gouty Arthritis

The aim of this study was to evaluate the expression of chemokine receptor CXCR4 and its ligand CXCL12 in patients with gout and uric acid-induced inflammation. A total of 40 patients with intercritical gout and 27 controls were consecutively enrolled. The serum levels of interleukin-1β (IL-1β), IL-18, CXCL12, and CXCR4 were assessed using an enzyme-linked immunosorbent assay. The gene and protein expressions for these target molecules were measured in human U937 cells incubated with monosodium urate (MSU) crystals using a real-time reverse transcription polymerase chain reaction and Western blot analysis. Patients with intercritical gout showed higher serum IL-1β, IL-18, and CXCL12 levels, but not the serum CXCR4 level, than in the controls.The serum CXCR4 level in gout patients was associated with the serum IL-18 level, uric acid level, and uric acid/creatinine ratio (r = 0.331, p = 0.037; r = 0.346, p = 0.028; and r = 0.361, p = 0.022, respectively). U937 cells treated with MSU crystals significantly induced the CXCL12 and CXCR4 mRNA and protein expression in addition to IL-1β and IL-18. In cells transfected with IL-1β siRNA or IL-18 siRNA, the CXCL12 and CXCR4 expression was downregulated compared with the non-transfected cells in MSU crystal-induced inflammation. In this study, we revealed that CXCL12 and CXCR4 were involved in the pathogenesis of uric acid-induced inflammation and gouty arthritis.

Tracing G-Protein-Mediated Contraction and Relaxation in Vascular Smooth Muscle Cell Spheroids

Analyses of G-protein-mediated contraction and relaxation of vascular smooth muscle cells (VSMCs) are usually hampered by a rigid growth surface and culture conditions promoting cell proliferation and a less contractile phenotype. Our studies indicated that mouse aortic VSMCs cultured in three-dimensional spheroids acquire a quiescent contractile status while decreasing the baseline G-protein-dependent inositolphosphate formation and increasing the expression of endothelin receptor type A (Ednra). Endothelin-1 (ET-1) promoted inositolphosphate formation in VSMC spheroids, but not in VSMCs cultured under standard conditions. To trace ET-1-mediated contraction of VSMC spheroids, we developed an assay by adhering them to collagen hydrogels and recording structural changes by time-lapse microscopy. Under these conditions, mouse and human VSMC spheroids contracted upon treatment with ET-1 and potassium chloride or relaxed in response to caffeine and the prostacyclin analogue Iloprost. ET-1 activated AKT-, MKK1-, and MKK3/6-dependent signaling cascades, which were inhibited by an overexpressing regulator of G-protein signaling 5 (Rgs5) to terminate the activity of Gα subunits. In summary, culture of VSMCs in three-dimensional spheroids lowers baseline G-protein activity and enables analyses of both contraction and relaxation of mouse and human VSMCs. This model serves as a simple and versatile tool for drug testing and investigating G-protein-depending signaling.

The regulatory role of Gnao1 protein in diabetic encephalopathy in KK-Ay mice and streptozotocin-induced diabetic rats

AIMS

To investigate the regulation and functional role of Gnao1 in the brain of diabetic encephalopathy (DE) in various animal models.

RESULTS

Data from the biochemical and behavioral studies showed that DE models were successful induced in streptozotocin treatment animals and KK-Ay mice. Gnao1 was down regulated in the brain tissues of these two diabetes animal models with significant cognition deficiency. It suggested that the changes in DE are also related to dementia such as Alzheimer's disease (AD). Our study also showed that the expression of adrenergic α2 receptor (Adr-α2R), the upstream protein of Gnao1, was decreased in DE animal models. Furthermore, many downstream proteins of Gnao1 also altered, among which cAMP and PKA proteins were increased, CREB and BDNF proteins were decreased both in animal models and in the cell levels. In addition, Gnao1 silencing leads to the increase of reactive oxygen species (ROS) and the decreased proliferation in cultured primary astrocytes, which means that the deficiency of Gnao1 might not be benefit for DE.

CONCLUSION

Our findings demonstrated the importance of Gnao1 in DE and suggested Gnao1 as a novel marker and a promising therapeutic target for DE and dementia in animal models.

Extremely low frequency electromagnetic stimulation reduces ischemic stroke volume by improving cerebral collateral blood flow

Extremely low frequency electromagnetic stimulation (ELF-EMS) has been considered as a neuroprotective therapy for ischemic stroke based on its capacity to induce nitric oxide (NO) signaling. Here, we examined whether ELF-EMS reduces ischemic stroke volume by stimulating cerebral collateral perfusion. Moreover, the pathway responsible for ELF-EMS-induced NO production was investigated. ELF-EMS diminished infarct growth following experimental stroke in collateral-rich C57BL/6 mice, but not in collateral-scarce BALB/c mice, suggesting that decreased lesion sizes after ELF-EMS results from improved collateral blood flow. In vitro analysis demonstrated that ELF-EMS increased endothelial NO levels by stimulating the Akt-/eNOS pathway. Furthermore, ELF-EMS augmented perfusion in the hind limb of healthy mice, which was mediated by enhanced Akt-/eNOS signaling. In healthy C57BL/6 mouse brains, ELF-EMS treatment increased cerebral blood flow in a NOS-dependent manner, whereas no improvement in cerebrovascular perfusion was observed in collateral-sparse BALB/c mice. In addition, ELF-EMS enhanced cerebral blood flow in both the contra- and ipsilateral hemispheres of C57BL/6 mice subjected to experimental ischemic stroke. In conclusion, we showed that ELF-EMS enhances (cerebro)vascular perfusion by stimulating NO production, indicating that ELF-EMS could be an attractive therapeutic strategy for acute ischemic stroke by improving cerebral collateral blood flow.

Relaxin/serelaxin for cardiac dysfunction and heart failure in hypertension

The pregnancy related hormone relaxin is produced throughout the reproductive system. However, relaxin also has important cardiovascular effects as part of the adaptation that the cardiovascular system undergoes in response to the extra demands of pregnancy. These effects are primarily mediated by the relaxin family peptide receptor 1, which is one of four known relaxin receptors. The effects of relaxin on the cardiovascular system during pregnancy, as well as its anti-fibrotic and anti-inflammatory properties, have led to extensive studies into the potential of relaxin therapy as an approach to treat heart failure. Cardiomyocytes, cardiac fibroblasts, and endothelial cells all possess relaxin family peptide receptor 1, allowing for direct effects of therapeutic relaxin on the heart. Many pre-clinical animal studies have demonstrated a beneficial effect of exogenous relaxin on adverse cardiac remodeling including inflammation, fibrosis, cardiomyocyte hypertrophy and apoptosis, as well as effects on cardiac contractile function. Despite this, clinical studies have yielded disappointing results for the synthetic seralaxin, even though seralaxin was well tolerated. This article will provide background on relaxin in the context of normal physiology, as well as the role of relaxin in pregnancy-related adaptations of the cardiovascular system. We will also present evidence from pre-clinical animal studies that demonstrate the potential benefits of relaxin therapy, as well as discussing the results from clinical trials. Finally, we will discuss possible reasons for the failure of these clinical trials as well as steps being taken to potentially improve relaxin therapy for heart failure.

Towards Kinase Inhibitor Therapies for Fragile X Syndrome: Tweaking Twists in the Autism Spectrum Kinase Signaling Network

Absence of the Fragile X Mental Retardation Protein (FMRP) causes autism spectrum disorders and intellectual disability, commonly referred to as the Fragile X syndrome. FMRP is a negative regulator of protein translation and is essential for neuronal development and synapse formation. FMRP is a target for several post-translational modifications (PTMs) such as phosphorylation and methylation, which tightly regulate its cellular functions. Studies have indicated the involvement of FMRP in a multitude of cellular pathways, and an absence of FMRP was shown to affect several neurotransmitter receptors, for example, the GABA receptor and intracellular signaling molecules such as Akt, ERK, mTOR, and GSK3. Interestingly, many of these molecules function as protein kinases or phosphatases and thus are potentially amendable by pharmacological treatment. Several treatments acting on these kinase-phosphatase systems have been shown to be successful in preclinical models; however, they have failed to convincingly show any improvements in clinical trials. In this review, we highlight the different protein kinase and phosphatase studies that have been performed in the Fragile X syndrome. In our opinion, some of the paradoxical study conclusions are potentially due to the lack of insight into integrative kinase signaling networks in the disease. Quantitative proteome analyses have been performed in several models for the FXS to determine global molecular processes in FXS. However, only one phosphoproteomics study has been carried out in Fmr1 knock-out mouse embryonic fibroblasts, and it showed dysfunctional protein kinase and phosphatase signaling hubs in the brain. This suggests that the further use of phosphoproteomics approaches in Fragile X syndrome holds promise for identifying novel targets for kinase inhibitor therapies.

G-protein coupled receptor 34 regulates the proliferation and growth of LS174T cells through differential expression of PI3K subunits and PTEN

PURPOSE

G-protein coupled receptor (GPR 34) has been found to play important roles in some cancers and regulates the proliferation, apoptosis, and migration of these cancer cells. However, the mechanisms underlying how GPR34 functions to regulate growth and proliferation of colorectal cancer cells remains to be clarified.

METHODS

We employed stable GPR34 knockdown LS174T cell models, GPR34 Mab blocking, a CCK-8 kit, and a colony formation assay to characterize the effect of GPR34 on the proliferation of LS174T in vitro and xenograft tumor growth in vivo. The mRNA level of GPR34 was detected by RT-PCR in tumor tissues and adjacent normal tissues from 34 CRC patients.

RESULTS

Based on RT-PCR results, GPR34 exhibited high level in tumor samples compared with adjacent normal samples. Increased expression of GPR34 is more associated with poor prognosis of CRC as shown in The Cancer Genome Atlas (TCGA) dataset by Kaplan-Meier survival analysis. Furthermore, we showed that GPR34 knockdown inhibited the proliferation of LS174T colon cancer cells and related xenograft tumor growth. Searching for the distinct molecular mechanism, we identified several contributors to proliferation of LS174T colon cancer cells: PI3K subunits/PTEN, PDK1/AKT, and Src/Raf/Ras/ERK. GPR34 knockdown inhibited the proliferation of LS174T cells by upregulating expression of PTEN, and downregulating expression of PI3K subunits p110-beta.

CONCLUSION

Our findings provide direct evidence that GPR34 regulates the proliferation of LS174T cells and the growth of LS174T tumor xenografts by regulating different pathways. High expression of GPR34 mRNA could then be used to predict poor prognosis of CRC.

Diallyl Trisulfide Enhances the Survival of Multiterritory Perforator Skin Flaps

The multiterritory perforator flap is one of the widest flap patterns used to repair tissue defects. However, flap necrosis of the distal part is still a challenging issue for plastic surgeons. Diallyl trisulfide (DATS) is an efficient ingredient extracted from garlic, exerting many important effects on different diseases. Our experiment aims to reveal whether DATS has a beneficial effect on the survival of perforator flaps and to explore its mechanism of action. The results showed that DATS enhanced angiogenesis and autophagy and reduced cell apoptosis and oxidative stress, thereby improving the survival rate of skin flaps. After co-administration with autophagy inhibitor 3-methyladenine (3MA), perforator flap survival was further improved. Mechanistically, we showed that PI3K/Akt and AMPK-HIF-1α signaling pathways in flap were activated under DATS treatment. All in all, DATS promoted the survival of multiterritory perforator flaps via the synergistic regulation of PI3K/Akt and AMPK-HIF-1α signaling pathways, and inhibition of DATS-induced autophagy further improves flap survival.

GqPCR-stimulated dephosphorylation of AKT is induced by an IGBP1-mediated PP2A switch

BACKGROUND

G protein-coupled receptors (GPCRs) usually regulate cellular processes via activation of intracellular signaling pathways. However, we have previously shown that in several cell lines, GqPCRs induce immediate inactivation of the AKT pathway, which leads to JNK-dependent apoptosis. This apoptosis-inducing AKT inactivation is essential for physiological functions of several GqPCRs, including those for PGF2α and GnRH.

METHODS

Here we used kinase activity assays of PI3K and followed phosphorylation state of proteins using specific antibodies. In addition, we used coimmunoprecipitation and proximity ligation assays to follow protein-protein interactions. Apoptosis was detected by TUNEL assay and PARP1 cleavage.

RESULTS

We identified the mechanism that allows the unique stimulated inactivation of AKT and show that the main regulator of this process is the phosphatase PP2A, operating with the non-canonical regulatory subunit IGBP1. In resting cells, an IGBP1-PP2Ac dimer binds to PI3K, dephosphorylates the inhibitory pSer608-p85 of PI3K and thus maintains its high basal activity. Upon GqPCR activation, the PP2Ac-IGBP1 dimer detaches from PI3K and thus allows the inhibitory dephosphorylation. At this stage, the free PP2Ac together with IGBP1 and PP2Aa binds to AKT, causing its dephosphorylation and inactivation.

CONCLUSION

Our results show a stimulated shift of PP2Ac from PI3K to AKT termed "PP2A switch" that represses the PI3K/AKT pathway, providing a unique mechanism of GPCR-stimulated dephosphorylation. Video Abstract.

Integrating network pharmacology and experimental evidence to decipher the cardioprotective mechanism of Yiqihuoxue decoction in rats after myocardial infarction

ETHNOPHARMACOLOGICAL RELEVANCE

"Qi deficiency and blood stasis" syndrome is one of the most common syndromes treated with Traditional Chinese Medicine among ischemic heart disease (IHD) patients in clinic. As a Chinese herbal formula with the function of tonifying Qi and activating blood, Yiqihuoxue Decoction (YQHX) has been frequently proven to be effective in the clinical treatment of IHD.

AIM OF THE STUDY

The cardioprotective mechanisms of YQHX in treating ischemic heart disease were investigated, with emphasis on the key targets and pathways.

MATERIALS AND METHODS

In the present study, the potential targets of compounds identified in YQHX were predicted using PharmMapper, Symmap, and STITCH databases, and a "herb-compound-target" network was constructed using Cytoscape. Subsequently, the GO and KEGG functional enrichment analyses were analyzed using the DAVID database. Furthermore, a protein-protein interaction network was constructed using STRING to obtain the key target information. Besides, we used a myocardial ischemia rat model to investigate the cardioprotective effects of YQHX. Transmission electron microscopy and Western blotting were used to observe apoptotic bodies and confirm protein expressions of key candidate targets, respectively.

RESULTS

Network pharmacology showed that a total of 141 potential targets were obtained from these databases. The functional analysis results revealed that the targets of YQHX were largely associated with apoptosis, and the PI3K-AKT and MAPK pathways might represent key functional pathways. The hub genes of network include ALB, TP53, AKT1, TNF, VEGFA, EGFR, MAPK1, CASP3, JUN, FN1, MMP9, and MAPK8. In vivo, YQHX significantly improved cardiac function and suppressed apoptosis in ischemic rat myocardium. Furthermore, YQHX could significantly upregulate Nrf2 and HO-1 expression, and inhibit JNK phosphorylation.

CONCLUSIONS

Based on network pharmacology and experimental evidence, this study proves that the cardioprotective effects and mechanisms of YQHX depend on multi-component, multi-target, and multi-pathway. In particular, YQHX exerts anti-apoptotic effects potentially by regulating the Nrf2/HO-1 and JNK-MAPK pathways.

G-protein coupled receptor, PI3K and Rho signaling pathways regulate the cascades of Tau and amyloid-β in Alzheimer's disease

Alzheimer's disease is a progressive neurodegenerative disease characterized by the presence of amyloid-β plaques in the extracellular environment and aggregates of Tau protein that forms neurofibrillary tangles (NFTs) in neuronal cells. Along with these pathological proteins, the disease shows neuroinflammation, neuronal death, impairment in the immune function of microglia and synaptic loss, which are mediated by several important signaling pathways. The PI3K/Akt-mediated survival-signaling pathway is activated by many receptors such as G-protein coupled receptors (GPCRs), triggering receptor expressed on myeloid cells 2 (TREM2), and lysophosphatidic acid (LPA) receptor. The signaling pathway not only increases the survival of neurons but also regulates inflammation, phagocytosis, cellular protection, Tau phosphorylation and Aβ secretion as well. In this review, we focused on receptors, which activate PI3K/Akt pathway and its potential to treat Alzheimer's disease. Among several membrane receptors, GPCRs are the major drug targets for therapy, and GPCR signaling pathways are altered during Alzheimer's disease. Several GPCRs are involved in the pathogenic progression, phosphorylation of Tau protein by activation of various cellular kinases and are involved in the amyloidogenic pathway of amyloid-β synthesis. Apart from various GPCR signaling pathways, GPCR regulating/ interacting proteins are involved in the pathogenesis of Alzheimer's disease. These include several small GTPases, Ras homolog enriched in brain, GPCR associated sorting proteins, β-arrestins, etc., that play a critical role in disease progression and has been elaborated in this review.

MAPK, AKT/FoxO3a and mTOR pathways are involved in cadmium regulating the cell cycle, proliferation and apoptosis of chicken follicular granulosa cells

The occurrence of cadmium (Cd) in feed is a major problem in animal health and production. Studies have confirmed that Cd depresses egg production of laying hens, which is closely related to follicular atresia. This study aimed to assess the toxic impacts of Cd on the ovarian tissue, and to examine the mechanism of Cd-induced granulosa cell proliferation and apoptosis. Results from the nitric oxide (NO) and malondialdehyde (MDA) content, total superoxide dismutase (T-SOD), glutathione peroxide (GSH-Px), total nitric oxide synthase (T-NOS) and adenosine triphosphatase (ATPase) activities, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay, and hematoxylin-eosin (H & E) staining indicated that excess Cd induced oxidative stress, granulosa cell apoptosis and follicular atresia in the layer ovary. Low-dose Cd exposure (1 μM) induced the granulosa cell proliferation, upregulated the mRNA levels of RSK1 and RHEB, activated FoxO3a, AKT, ERK1/2, mTOR and p70S6K1 phosphorylation, and promoted cell cycle progression from phase G1 to S. However, high-dose Cd exposure (15 μM) induced reactive oxygen species (ROS) generation and cell apoptosis, upregulated the mRNA levels of the inflammatory factors, ASK1, JNK, p38 and TAK1, downregulated the expressions of RSK1 and RHEB genes, and inhibited the phosphorylation of ERK1/2, mTOR and p70S6K1 proteins, and the cell cycle progression. Rapamycin pre-treatment completely blocked the phosphorylation of mTOR and p70S6K1 proteins, and the cell cycle progression induced by 1 μM Cd, and accelerated 15 μM Cd-induced cell apoptosis and cell cycle arrest. The microRNA sequencing result showed that 15 μM Cd induced differential expression of microRNA genes, which may regulate AKT, ERK1/2 and mTOR signaling and cell cycle progression by regulating the activity of G proteins and cell cycle-related proteins. Conclusively, these results indicated that Cd can cause the ovarian damage and follicular atresia, and regulate cell cycle, cell proliferation or apoptosis of granulosa cells through MAPK, AKT/FoxO3a and mTOR pathways in laying hens.

Advancing of Cellular Signaling Pathways in Respiratory Diseases Using Nanocarrier Based Drug Delivery Systems

Cell Signaling pathways form an integral part of our existence that allows the cells to comprehend a stimulus and respond back. Such reactions to external cues from the environment are required and are essential to regulate the normal functioning of our body. Abnormalities in the system arise when there are errors developed in these signals, resulting in a complication or a disease. Presently, respiratory diseases contribute to being the third leading cause of morbidity worldwide. According to the current statistics, over 339 million people are asthmatic, 65 million are suffering from COPD, 2.3 million are lung cancer patients and 10 million are tuberculosis patients. This toll of statistics with chronic respiratory diseases leaves a heavy burden on society and the nation's annual health expenditure. Hence, a better understanding of the processes governing these cellular pathways will enable us to treat and manage these deadly respiratory diseases effectively. Moreover, it is important to comprehend the synergy and interplay of the cellular signaling pathways in respiratory diseases, which will enable us to explore and develop suitable strategies for targeted drug delivery. This review, in particular, focuses on the major respiratory diseases and further provides an in-depth discussion on the various cell signaling pathways that are involved in the pathophysiology of respiratory diseases. Moreover, the review also analyses the defining concepts about advanced nano-drug delivery systems involving various nanocarriers and propose newer prospects to minimize the current challenges faced by researchers and formulation scientists.

Positive Effect of Andrographolide Induced Autophagy on Random-Pattern Skin Flaps Survival

Random-pattern skin flap replantation is generally used in the reconstruction of surgical tissues and covering a series of skin flap defects. However, ischemia often occurs at the flap distal parts, which lead to flap necrosis. Previous studies have shown that andrographolide (Andro) protects against ischemic cardiovascular diseases, but little is known about the effect of Andro on flap viability. Thus, our study aimed to building a model of random-pattern skin flap to understand the mechanism of Andro-induced effects on flap survival. In this study, fifty-four mice were randomly categorized into the control, Andro group, and the Andro+3-methyladenine group. The skin flap samples were obtained on postoperative day 7. Subsequently, the tissue samples were underwent a series of evaluations such as changes in the appearance of flap tissue, the intensity of blood flow, and neovascularization density of skin flap. In our study, the results revealed that Andro enhanced the viability of random skin flaps by enhancing angiogenesis, inhibiting apoptosis, and reducing oxidative stress. Furthermore, our results have also demonstrated that the administration of Andro caused an elevation in the autophagy, and these remarkable impact of Andro were reversed by 3-methyladenine (3-MA), the most common autophagy inhibitor. Together, our data proves novel evidence that Andro is a potent modulator of autophagy capable of significantly increasing random-pattern skin flap survival.

p-synephrine induces transcriptional changes via the cAMP/PKA pathway but not cytotoxicity or mutagenicity in human gastrointestinal cells

p-Synephrine (SN) is an alkaloid added to thermogenic formulations for weight loss that is predominantly absorbed in the human gastrointestinal tract (GI). As the adverse effects of SN on GI cells remain unclear, the aim of present study was to examine whether SN affected cell viability, cell cycle kinetics, genomic stability, redox status, and expression of cAMP/PKA pathway genes related to metabolism/energy homeostasis in stomach mucosa (MNP01) and colon adenocarcinoma (Caco-2) human cells. p-Synephrine at 25-5000 μM was not cytotoxic to both cell lines. At 2-200 μM, SN increased the formation of reactive oxygen species (ROS) but also enhanced levels of antioxidant defense molecules glutathione (GSH) and catalase (CAT) activity, which may account for the absence of cytotoxicity/mutagenicity in both cell lines. SN induced expression of the cAMP/PKA pathway genes ADCY3 and MAPK1 in MNP01 cells and MAPK1, GNAS, PRKACA, and PRKAR2A in Caco-2 cells, as well as modulated the transcription of genes related to cell proliferation (JUN; AKT1) and inflammation (RELA; TNF) in both cell lines. Therefore, the improved antioxidant state mitigated pro-oxidative effects attributed to SN. Evidence indicates that SN does not appear to exhibit adverse potential but modulated the cAMP/PKA pathway in human GI cell lines.

Cancer-driving mutations and variants of components of the membrane trafficking core machinery

The core machinery for vesicular membrane trafficking broadly comprises of coat proteins, RABs, tethering complexes and SNAREs. As cellular membrane traffic modulates key processes of mitogenic signaling, cell migration, cell death and autophagy, its dysregulation could potentially results in increased cell proliferation and survival, or enhanced migration and invasion. Changes in the levels of some components of the core machinery of vesicular membrane trafficking, likely due to gene amplifications and/or alterations in epigenetic factors (such as DNA methylation and micro RNA) have been extensively associated with human cancers. Here, we provide an overview of association of membrane trafficking with cancer, with a focus on mutations and variants of coat proteins, RABs, tethering complex components and SNAREs that have been uncovered in human cancer cells/tissues. The major cellular and molecular cancer-driving or suppression mechanisms associated with these components of the core membrane trafficking machinery shall be discussed.

The Chemokine Receptor CXCR4 in Cell Proliferation and Tissue Regeneration

The CXCR4 receptor upon binding its ligands triggers multiple signaling pathways that orchestrate cell migration, hematopoiesis and cell homing, and retention in the bone marrow. However, CXCR4 also directly controls cell proliferation of non-hematopoietic cells. This review focuses on recent reports pointing to its pivotal role in tissue regeneration and stem cell activation, and discusses the connection to the known role of CXCR4 in promoting tumor growth. The mechanisms may be similar in all cases, since regeneration often recapitulates developmental processes, and cancer often exploits developmental pathways. Moreover, cell migration and cell proliferation appear to be downstream of the same signaling pathways. A deeper understanding of the complex signaling originating from CXCR4 is needed to exploit the opportunities to repair damaged organs safely and effectively.

Effects of chitosan and oligochitosans on the phosphatidylinositol 3-kinase-AKT pathway in cancer therapy

Phosphatidylinositol 3-kinase (PI3K)-AKT pathway is one of the most important kinase signaling networks in the context of cancer development and treatment. Aberrant activation of AKT, the central mediator of this pathway, has been implicated in numerous malignancies including endometrial, hepatocellular, breast, colorectal, prostate, and, cervical cancer. Thus regulation and blockage of this kinase and its key target nodes is an attractive approach in cancer therapy and diverse efforts have been done to achieve this aim. Chitosan is a carbohydrate with multiple interesting applications in cancer diagnosis and treatment strategies. This bioactive polymer and its derivative oligomers commonly used in drug/DNA delivery methods due to their functional properties which improve efficiency of delivery systems. Further, these compounds exert anti-tumor roles through the stimulation of apoptosis, immune enhancing potency, anti-oxidative features and anti-angiogenic roles. Due to the importance of PI3K-AKT signaling in cancer targeting and treatment resistance, this review discusses the involvement of chitosan, oligochitosaccharides and carriers based on these chemicals in the regulation of this pathway in different tumors.

Misaligned foveal morphology and sector retinal dysfunction in AKT1-mosaic Proteus syndrome

PURPOSE

Proteus syndrome arises as a result of a post-zygotic mosaic activating mutation in the AKT1 oncogene, causing a disproportionate overgrowth of affected tissues. A small number of ocular complications have been reported. We present the unique findings in a patient who had molecular confirmation of AKT1 mosaicism alongside fulfilling the clinical criteria for Proteus syndrome.

METHODS

Pattern electroretinography, visual evoked potentials and multifocal electroretinography testing were performed alongside detailed retinal imaging and clinical examination to detail the ophthalmic characteristics.

RESULTS

Electrophysiological findings characterised unilateral macular dysfunction alongside sector retinal dysfunction of the right eye. This was demonstrated through optical coherence tomography and ultra-wide-field imaging to be associated with a misaligned foveal morphology and sector retinal dysfunction extending into the temporal retina.

CONCLUSION

We propose this patient has asymmetric foveal development and concomitant sector retinal dysfunction as the result of the mosaic AKT1 mutation, either through disruption in the retinal PI3K-AKT1 signalling pathway or through mechanical distortion of ocular growth, resulting in disproportionate inner retinal development. The findings expand the ocular phenotype of Proteus syndrome and encourage early assessment to identify any incipient ocular abnormalities.

Detrimental Effect of Sitagliptin Induced Autophagy on Multiterritory Perforator Flap Survival

Multiterritory perforator flap survival is commonly applied in surgical tissue reconstructions and covering of large skin defects. However, multiple risk factors such as ischemia, reperfusion injury, and apoptosis after reconstructive surgeries cause necrosis in distal parts with outcomes ranging from poor aesthetic appearance to reconstructive failure. A few studies have reported that sitagliptin (Sit) promotes angiogenesis and inhibits apoptosis. However, little is known about Sit-induced autophagy especially on the flap model. Therefore, our study investigated the effect of Sit and its induced autophagy on the perforator flap survival. Ninety male Sprague-Dawley rats were randomly separated into control, Sit, and Sit+3-methyladenine group. Results revealed that Sit significantly promoted flap survival by enhancing angiogenesis, reducing oxidative stress, and attenuating apoptosis. In addition, flap survival was further improved after co-administration with 3-methyladenine to inhibit autophagy. Overall, our results established that Sit has positive effects in promoting survival of multiterritory perforator flap. Sit-induced autophagy was detrimental for flap survival and its inhibition may further improve flap survival.

Comparative Analysis of the Biosimilar and Innovative G-CSF Modulated Pathways on Umbilical Cord Blood-Derived Mononuclear Cells

Biosimilars of granulocyte colony-stimulating factor (G-CSF) have been routinely introduced into clinical practice. However, not functional genomics characterization has been performed yet in comparison with the innovator G-CSF. This study aimed to evaluate the transcriptomic changes in an in vitro model of umbilical cord blood cells (UBC) exposed to G-CSF for the identification of their modulated pathways. Umbilical cord blood cells-derived mononuclear cells (MNCs) were treated with biosimilar and innovator G-CSF for further gene expression profiling analysis using a microarray-based platform. Comparative analysis of biosimilar and innovator G-CSF gene expression signatures allowed us to identify the most commonly modulated pathways by both drugs. In brief, we observed predominantly upmodulation of transcripts related to PI3K-Akt, NF-kappaB, and tumor necrosis factor (TNF) signaling pathways as well as transcripts related to negative regulation of apoptotic process among others. In addition, hematopoietic colony-forming cell assays corroborate the G-CSF phenotypic effects over UBC-derived MNCs. In conclusion, our study suggests that G-CSF impacts UBC-derived cells through the modulation of several signaling pathways associated with cell survival, migration, and proliferation. The concordance observed between biosimilar and innovator G-CSF emphasizes their similarity in regards to their specificity and biological responses.

The peripheral CB1 receptor antagonist JD5037 attenuates liver fibrosis via a CB1 receptor/β-arrestin1/Akt pathway

BACKGROUND AND PURPOSE

Liver fibrosis is a serious cause of morbidity and mortality worldwide and has no adequate treatment. Accumulating evidence suggests that cannabinoid CB₁ receptors regulate a variety of physiological and pathological processes in the liver, and blockage of CB₁ receptor signalling shows promise as a new therapy for several liver diseases. The aim of this study was to investigate the potential therapeutic effects of CB₁ receptors and a peripheral CB₁ receptor antagonist JD5037 in liver fibrogenesis.

EXPERIMENTAL APPROACH

Liver samples from both humans and mouse models were investigated. The peripheral CB₁ receptor antagonist JD5037, β-arr1 wild type (β-arr1-WT) and β-arr1 knockout (β-arr1-KO) littermate models, and primary hepatic stellate cells (HSCs) were also used. The mechanisms underlying CB₁ receptor-regulated HSCs activation in fibrosis and the therapeutic potential of JD5037 were further analysed.

KEY RESULTS

CB₁ receptors were induced in samples from patients with liver fibrosis and from mouse models. These receptors promoted activation of HSCs in liver fibrosis via recruiting β-arrestin1 and Akt signalling, while blockage of CB₁ receptors with JD5037 attenuated CB₁ receptor-regulated HSCs activation and liver fibrosis by suppressing β-arrestin1/Akt signalling.

CONCLUSIONS AND IMPLICATIONS

CB₁ receptors promote the activation of HSCs and liver fibrosis via the β-arrestin1/Akt signalling pathway. The peripheral CB₁ receptor antagonist JD5037 blocked this pathway, the activation of HSCs and liver fibrosis. This compound and the associated pathway may be a novel approach to the treatment of liver fibrosis.

Dracorhodin perchlorate induces apoptosis and G2/M cell cycle arrest in human esophageal squamous cell carcinoma through inhibition of the JAK2/STAT3 and AKT/FOXO3a pathways

Dracorhodin perchlorate (DP), a synthetic analogue of the anthocyanin red pigment dracorhodin, has been shown to exert various pharmacological effects, including anticancer activity. However, its effects on human esophageal squamous cell carcinoma (ESCC) cells have not been previously investigated, and the molecular mechanisms underlying its anticancer activity remain unclear. In the present study, it was demonstrated that DP significantly reduced the viability of ESCC cells compared with that noted in normal human liver LO2 cells. Treatment with DP induced G2/M phase cell cycle arrest through upregulation of p21 and p27, and downregulation of cyclin B1 and Cdc2. Furthermore, DP treatment induced caspase‑dependent apoptosis, which could be reversed by exposure to Z‑VAD‑FMK, a caspase inhibitor. Western blotting demonstrated that DP induced apoptosis through extrinsic and intrinsic pathways by upregulating death receptor 4 (DR4), DR5, cleaved caspase‑3/‑7/‑9 and cleaved poly (ADP‑ribose) polymerase (PARP), and by decreasing total PARP, total caspase‑3/7, Bcl‑2 and caspase‑9/‑10. Moreover, DP treatment decreased the phosphorylation of Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), AKT, and forkhead box O3a (FOXO3a) in ESCC cells, indicating that the activity of the JAK2/STAT3 and AKT/FOXO3a signaling pathways was inhibited. Therefore, DP is a promising therapeutic agent for ESCC.

Over-expression of JAZF1 promotes cardiac microvascular endothelial cell proliferation and angiogenesis via activation of the Akt signaling pathway in rats with myocardial ischemia-reperfusion

Myocardial ischemia-reperfusion (I/R) injury is caused by endothelial dysfunction and enhanced oxidative stress. The overexpression of JAZF1, a zinc finger protein, has been reported to promote cell proliferation and suppress myogenic differentiation in type 2 diabetes. However, the involvement of JAZF1 in myocardial I/R injury remains to be unclear. The current study aims to investigate the role by which JAZF1 influences cardiac microvascular endothelial cells (CMECs) in a rat model of myocardial I/R injury. A total of 50 rats were established as a myocardial I/R model to isolate CMECs, with alterations in JAZF1 expression. After that, the gain- or loss-function of JAZF1 on the proliferation, apoptosis and tube formation ability of CMECs were evaluated by a series of in vitro experiments. Results indicated that JAZF1 was down-regulated in CMECs of rats with myocardial I/R injury. After treatment with JAZF1, the levels of VEGF, Bcl-2, PDGF and p-Akt/Akt were all increased; however, the expression of Bax, caspase-3, caspase-9, p-Bad/Bad, c-caspase-3/caspase-3, c-caspase-9/caspase-9, and p-FKHR/FKHR exhibited decreased levels; CMEC proliferation and angiogenesis were increased, while cell apoptosis was attenuated. CMECs transfected with JAZF1 shRNA exhibited the contrary tendencies. The key findings of this study suggest that the over-expression of JAZF1 alleviates myocardial I/R injury by enhancing proliferation and angiogenesis of CMECs and in turn inhibiting apoptosis of CMECs via the activation of the Akt signaling pathway.

Investigating the effects of Pirfenidone on TGF-β1 stimulated non-SMAD signaling pathways in Dupuytren's disease -derived fibroblasts

BACKGROUND

Dupuytren's disease (DD) is a progressive, debilitating condition of the hand that can eventually cause contractures of the affected fingers. Transforming growth factor- β1 (TGF-β1) has been reported to play a key role in DD pathology. Increased expression of TGF-β1 has shown to be the main stimulator of myofibroblast activity and in DD contractures. Pirfenidone (PFD), a small active molecule possess the ability to inhibit TGF-β1-mediated action in various fibrotic disorders. Our recent published findings show that PFD reduced TGF-β1-mediated cellular functions implicated in DD through SMAD signaling pathways. In the present study, the effect of PFD on TGF-β1-mediated non-SMAD signaling pathways were investigated in both carpal tunnel (CT) - and DD-derived fibroblasts.

METHODS

Fibroblasts harvested from Dupuytren's disease (DD) and carpal tunnel (CT) tissues were cultured in the presence or absence of TGF-β1 (10 ng/ml) and/or PFD (800 μg/ml). Cell lysates were analyzed using Western blots. Equal amounts of proteins were loaded to determine the phosphorylation levels of phosphatidylinositol-3 kinase (PI3K/AKT), extracellular regulated kinases (ERK1/2), p38 mitogen-activated protein kinase and Rho family related myosin light chain (MLC).

RESULTS

We show that the TGF-β1-induced phosphorylation of AKT was significantly decreased by the addition of PFD (800 μg/mL) in both CT- and DD-derived fibroblasts. Interestingly, there was no significant difference in the phosphorylation levels of both ERK and p38 on TGF-β1- induced cells in both CT-and DD-derived fibroblasts. But, PFD significantly decreased the TGF- β1-induced phosphorylation levels of ERK1/2 in both CT- and DD- cells. In contrast, PFD significantly decreased the basal and TGF- β1-induced phosphorylation levels of p38 in DD-derived fibroblasts. TGF- β1-induced phosphorylation levels of MLC was decreased by PFD in DD-derived fibroblasts.

CONCLUSIONS

These in-vitro results indicate for the first time that PFD has the potential to inhibit TGF-β1-induced non-SMAD signaling pathways in both CT- and DD-derived fibroblasts but pronounced statistically significant inhibition on all molecules was observed only in DD-derived fibroblasts. Our previous studies show that PFD can inhibit TGF-β1- induced SMAD signaling pathway proteins, namely p- SMAD2/SMAD3. These broad and complementary actions suggest PFD as a promising candidate to inhibit the TGF-β1- mediated molecular mechanisms leading to DD fibrosis.

Suppressive Role of Androgen/Androgen Receptor Signaling via Chemokines on Prostate Cancer Cells

Androgen/androgen receptor (AR) signaling is a significant driver of prostate cancer progression, therefore androgen-deprivation therapy (ADT) is often used as a standard form of treatment for advanced and metastatic prostate cancer patients. However, after several years of ADT, prostate cancer progresses to castration-resistant prostate cancer (CRPC). Androgen/AR signaling is still considered an important factor for prostate cancer cell survival following CRPC progression, while recent studies have reported dichotomic roles for androgen/AR signaling. Androgen/AR signaling increases prostate cancer cell proliferation, while simultaneously inhibiting migration. As a result, ADT can induce prostate cancer metastasis. Several C-C motif ligand (CCL)-receptor (CCR) axes are involved in cancer cell migration related to blockade of androgen/AR signaling. The CCL2-CCR2 axis is negatively regulated by androgen/AR signaling, with the CCL22-CCR4 axis acting as a further downstream mediator, both of which promote prostate cancer cell migration. Furthermore, the CCL5-CCR5 axis inhibits androgen/AR signaling as an upstream mediator. CCL4 is involved in prostate carcinogenesis through macrophage AR signaling, while the CCL21-CCR7 axis in prostate cancer cells is activated by tumor necrotic factor, which is secreted when androgen/AR signaling is inhibited. Finally, the CCL2-CCR2 axis has recently been demonstrated to be a key contributor to cabazitaxel resistance in CRPC.

CRF1 Receptor Signaling via the ERK1/2-MAP and Akt Kinase Cascades: Roles of Src, EGF Receptor, and PI3-Kinase Mechanisms

In the present study, we determined the cellular regulators of ERK1/2 and Akt signaling pathways in response to human CRF₁ receptor (CRF₁R) activation in transfected COS-7 cells. We found that Pertussis Toxin (PTX) treatment or sequestering Gβγ reduced CRF₁R-mediated activation of ERK1/2, suggesting the involvement of a G_i-linked cascade. Neither G_s/PKA nor G_q/PKC were associated with ERK1/2 activation. Besides, CRF induced EGF receptor (EGFR) phosphorylation at Tyr¹⁰⁶⁸, and selective inhibition of EGFR kinase activity by AG1478 strongly inhibited the CRF₁R-mediated phosphorylation of ERK1/2, indicating the participation of EGFR transactivation. Furthermore, CRF-induced ERK1/2 phosphorylation was not altered by pretreatment with batimastat, GM6001, or an HB-EGF antibody indicating that metalloproteinase processing of HB-EGF ligands is not required for the CRF-mediated EGFR transactivation. We also observed that CRF induced Src and PYK2 phosphorylation in a Gβγ-dependent manner. Additionally, using the specific Src kinase inhibitor PP2 and the dominant-negative-SrcYF-KM, it was revealed that CRF-stimulated ERK1/2 phosphorylation depends on Src activation. PP2 also blocked the effect of CRF on Src and EGFR (Tyr⁸⁴⁵) phosphorylation, further demonstrating the centrality of Src. We identified the formation of a protein complex consisting of CRF₁R, Src, and EGFR facilitates EGFR transactivation and CRF₁R-mediated signaling. CRF stimulated Akt phosphorylation, which was dependent on G_i/βγ subunits, and Src activation, however, was only slightly dependent on EGFR transactivation. Moreover, PI3K inhibitors were able to inhibit not only the CRF-induced phosphorylation of Akt, as expected, but also ERK1/2 activation by CRF suggesting a PI3K dependency in the CRF₁R ERK signaling. Finally, CRF-stimulated ERK1/2 activation was similar in the wild-type CRF₁R and the phosphorylation-deficient CRF₁R-Δ386 mutant, which has impaired agonist-dependent β-arrestin-2 recruitment; however, this situation may have resulted from the low β-arrestin expression in the COS-7 cells. When β-arrestin-2 was overexpressed in COS-7 cells, CRF-stimulated ERK1/2 phosphorylation was markedly upregulated. These findings indicate that on the base of a constitutive CRF₁R/EGFR interaction, the G_i/βγ subunits upstream activation of Src, PYK2, PI3K, and transactivation of the EGFR are required for CRF₁R signaling via the ERK1/2-MAP kinase pathway. In contrast, Akt activation via CRF₁R is mediated by the Src/PI3K pathway with little contribution of EGFR transactivation.

Structural properties and role of the endocannabinoid lipases ABHD6 and ABHD12 in lipid signalling and disease

The endocannabinoid (eCB) system is an important part of both the human central nervous system (CNS) and peripheral tissues. It is involved in the regulation of various physiological and neuronal processes and has been associated with various diseases. The eCB system is a complex network composed of receptor molecules, their cannabinoid ligands, and enzymes regulating the synthesis, release, uptake, and degradation of the signalling molecules. Although the eCB system and the molecular processes of eCB signalling have been studied extensively over the past decades, the involved molecules and underlying signalling mechanisms have not been described in full detail. An example pose the two poorly characterised eCB-degrading enzymes α/β-hydrolase domain protein six (ABHD6) and ABHD12, which have been shown to hydrolyse 2-arachidonoyl glycerol-the main eCB in the CNS. We review the current knowledge about the eCB system and the role of ABHD6 and ABHD12 within this important signalling system and associated diseases. Homology modelling and multiple sequence alignments highlight the structural features of the studied enzymes and their similarities, as well as the structural basis of disease-related ABHD12 mutations. However, homologies within the ABHD family are very low, and even the closest homologues have widely varying substrate preferences. Detailed experimental analyses at the molecular level will be necessary to understand these important enzymes in full detail.

Rimonabant, a potent CB1 cannabinoid receptor antagonist, is a Gαi/o protein inhibitor

Rimonabant is a potent and selective cannabinoid CB1 receptor antagonist widely used in animal and clinical studies. Besides its antagonistic properties, numerous studies have shown that, at micromolar concentrations rimonabant behaves as an inverse agonist at CB1 receptors. The mechanism underpinning this activity is unclear. Here we show that micromolar concentrations of rimonabant inhibited Gα_i/o-type G proteins, resulting in a receptor-independent block of G protein signaling. Accordingly, rimonabant decreased basal and agonist stimulated [³⁵S]GTPγS binding to cortical membranes of CB1- and GABA_B-receptor KO mice and Chinese Hamster Ovary (CHO) cell membranes stably transfected with GABA_B or D2 dopamine receptors. The structural analog of rimonabant, AM251, decreased basal and baclofen-stimulated GTPγS binding to rat cortical and CHO cell membranes expressing GABA_B receptors. Rimonabant prevented G protein-mediated GABA_B and D2 dopamine receptor signaling to adenylyl cyclase in Human Embryonic Kidney 293 cells and to G protein-coupled inwardly rectifying K⁺ channels (GIRK) in midbrain dopamine neurons of CB1 KO mice. Rimonabant suppressed GIRK gating induced by GTPγS in CHO cells transfected with GIRK, consistent with a receptor-independent action. Bioluminescent resonance energy transfer (BRET) measurements in living CHO cells showed that, in presence or absence of co-expressed GABA_B receptors, rimonabant stabilized the heterotrimeric Gαi/o-protein complex and prevented conformational rearrangements induced by GABA_B receptor activation. Rimonabant failed to inhibit Gαs-mediated signaling, supporting its specificity for Gα_i/o-type G proteins. The inhibition of Gα_i/o protein provides a new site of rimonabant action that may help to understand its pharmacological and toxicological effects occurring at high concentrations.

Lysophosphatidic acid represses autophagy in prostate carcinoma cells

Lysophosphatidic acid (LPA) is a small signaling phospholipid that mediates diverse functions including cell proliferation, migration, and survival by engaging LPA-agonized G-protein coupled receptors. Autophagy is a survival mechanism in response to nutrient depletion or organellar damage that encloses idle or damaged organelles within autophagosomes that are then delivered to lysosomes for degradation. However, the relationship between LPA and autophagy is largely unknown. The purpose of this study is to elucidate whether LPA affects autophagy through the ERK1/2 and (or) the Akt-mTOR signaling pathways. In this study, we investigated the effect of LPA on autophagy-regulating pathways in various prostate-derived cancer cells including PC3, LNCaP, and Du145 cells grown in complete medium and exposed to serum-free medium. Using Western blotting and ELISA, we determined that LPA stimulates the ERK and mTOR pathways in complete and serum-free medium. The mTOR pathway led to phosphorylation of S6K and ULK, which respectively stimulates protein synthesis and arrests autophagy. Consistent with this, LPA exposure suppressed autophagy as measured by LC3 maturation and formation of GFP-LC3 puncta. Altogether, these results suggest that LPA suffices to activate mTORC1 and suppress autophagy in prostate cancer cells.

Sitagliptin attenuates intestinal ischemia/reperfusion injury via cAMP/PKA, PI3K/Akt pathway in a glucagon-like peptide 1 receptor-dependent manner

AIMS

This study investigated the effect of sitagliptin prophylactic treatment on intestinal I/R rat model and explored the possible underlying mechanism.

MAIN METHODS

Forty-five male Sprague-Dawley rats were randomly assigned to 3 groups: Sham group (operation without clamping), I/R group (operation with clamping) and sitagliptin pretreated group (300 mg/kg/day; p.o.) for 2 weeks before I/R insult. Intestinal I/R was performed by clamping the superior mesenteric artery for 30 min, followed by 60 min reperfusion after removal of clamping. At the end of the experimental period, all rats were sacrificed for histopathological, biochemical, PCR and western blot assessment.

KEY FINDINGS

Pretreatment with sitagliptin remarkably alleviated the pathological changes induced by I/R in the jejunum, suppressed upregulated NF-κB, TNF-α, IL-1βand MPO caused by I/R. Moreover, sitagliptin decreased the Bax/Bcl-2 ratio and accordingly suppressed apoptotic tissue damage as reflected by a caspase-3 level reduction in rat intestine subjected to I/R injury. Interestingly, sitagliptin could obviously increase the active GLP-1 level and GLP-1 receptor mRNA expression in the jejunum of I/R rats. This was associated with the augmentation of the cAMP level and enhancement of PKA activity. Simultaneously, sitagliptin treatment was able to increase the protein expression levels of phosphorylated PI3K and Akt.

SIGNIFICANCE

Sitagliptin has shown protective effects against intestinal I/R injury in rats through reduction of intestinal inflammation and apoptosis. The molecular mechanisms may be partially correlated with activation of cAMP/PKA and PI3K/Akt signaling pathway by the GLP-1/GLP-1 receptor.

Sunitinib induces early histomolecular changes in a subset of renal cancer cells that contribute to resistance

Sunitinib is the standard-of-care, first-line treatment for advanced renal cell carcinoma (RCC). Characteristics of treatment-resistant RCC have been described; however, complex tumor adaptation mechanisms obstruct the identification of significant operators in resistance. We hypothesized that resistance is a late manifestation of early, treatment-induced histomolecular alterations; therefore, studying early drug response may identify drivers of resistance. We describe an epithelioid RCC growth pattern in RCC xenografts, which emerges in sunitinib-sensitive tumors and is augmented during resistance. This growth modality is molecularly and morphologically related to the RCC spheroids that advance during in vitro treatment. Based on time-lapse microscopy, mRNA and microRNA screening, and tumor behavior-related characteristics, we propose that the spheroid and adherent RCC growth patterns differentially respond to sunitinib. Gene expression analysis indicated that sunitinib promoted spheroid formation, which provided a selective survival advantage under treatment. Functional studies confirm that E-cadherin is a key contributor to the survival of RCC cells under sunitinib treatment. In summary, we suggest that sunitinib-resistant RCC cells exist in treatment-sensitive tumors and are histologically identifiable.-Lichner, Z., Saleeb, R., Butz, H., Ding, Q., Nofech-Mozes, R., Riad, S., Farag, M., Varkouhi, A. K., dos Santos, C. C., Kapus, A., Yousef, G. M. Sunitinib induces early histomolecular changes in a subset of renal cancer cells that contribute to resistance.

Loss of IGF1R in Human Astrocytes Alters Complex I Activity and Support for Neurons

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We have established a novel human astrocyte-neuron co-culture system.

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Astrocytes provided contact-mediated support for neurite outgrowth.

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IGF1R-impaired astrocytes are less able to protect neurons under stress conditions.

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Microarray analysis of these astrocytes identified changes in energy metabolism.

The insulin/insulin-like growth factor 1 (IGF1) signaling pathways are implicated in longevity and in progression of Alzheimer’s disease. Previously, we showed that insulin-like growth factor 1 receptor (IGF1R) and downstream signaling transcripts are reduced in astrocytes in human brain with progression of Alzheimer’s neuropathology and developed a model of IGF1 signaling impairment in human astrocytes using an IGF1R-specific monoclonal antibody, MAB391. Here, we have established a novel human astrocyte-neuron co-culture system to determine whether loss of astrocytic IGF1R affects their support for neurons. Astrocyte-neuron co-cultures were developed using human primary astrocytes and differentiated Lund Human Mesencephalic Cells (LUHMES). Neurite outgrowth assays, performed to measure astrocytic support for neurons, showed astrocytes provided contact-mediated support for neurite outgrowth. Loss of IGF1R did not affect neurite outgrowth under control conditions but when challenged with hydrogen peroxide IGF1R-impaired astrocytes were less able to protect LUHMES. To determine how loss of IGF1R affects neuronal support MAB391-treated astrocytes were FACS sorted from GFP-LUHMES and their transcriptomic profile was investigated using microarrays. Changes in transcripts involved in astrocyte energy metabolism were identified, particularly NDUFA2 and NDUFB6, which are related to complex I assembly. Loss of complex I activity in MAB391-treated astrocytes validated these findings. In conclusion, reduced IGF1 signaling in astrocytes impairs their support for neurons under conditions of stress and this is associated with defects in the mitochondrial respiratory chain in astrocytes.

Using coordinate-based meta-analyses to explore structural imaging genetics

Imaging genetics has become a highly popular approach in the field of schizophrenia research. A frequently reported finding is that effects from common genetic variation are associated with a schizophrenia-related structural endophenotype. Genetic contributions to a structural endophenotype may be easier to delineate, when referring to biological rather than diagnostic criteria. We used coordinate-based meta-analyses, namely the anatomical likelihood estimation (ALE) algorithm on 30 schizophrenia-related imaging genetics studies, representing 44 single-nucleotide polymorphisms at 26 gene loci investigated in 4682 subjects. To test whether analyses based on biological information would improve the convergence of results, gene ontology (GO) terms were used to group the findings from the published studies. We did not find any significant results for the main contrast. However, our analysis enrolling studies on genotype × diagnosis interaction yielded two clusters in the left temporal lobe and the medial orbitofrontal cortex. All other subanalyses did not yield any significant results. To gain insight into possible biological relationships between the genes implicated by these clusters, we mapped five of them to GO terms of the category "biological process" (AKT1, CNNM2, DISC1, DTNBP1, VAV3), then five to "cellular component" terms (AKT1, CNNM2, DISC1, DTNBP1, VAV3), and three to "molecular function" terms (AKT1, VAV3, ZNF804A). A subsequent cluster analysis identified representative, non-redundant subsets of semantically similar terms that aided a further interpretation. We regard this approach as a new option to systematically explore the richness of the literature in imaging genetics.

The free fatty acid receptor 1 promotes airway smooth muscle cell proliferation through MEK/ERK and PI3K/Akt signaling pathways

Obesity is a risk factor for asthma and influences airway hyperresponsiveness, which is in part modulated by airway smooth muscle proliferative remodeling. Plasma free fatty acids (FFAs) levels are elevated in obese individuals, and long-chain FFAs act as endogenous ligands for the free fatty acid receptor 1 (FFAR1), which couples to both Gq and Gi proteins. We examined whether stimulation of FFAR1 induces airway smooth muscle cell proliferation through classical MEK/ERK and/or phosphoinositide 3-kinase (PI3K)/Akt signaling pathways. The long-chain FFAs (oleic acid and linoleic acid) and a FFAR1 agonist (GW9508) induced human airway smooth muscle (HASM) cell proliferation, which was inhibited by the MEK inhibitor U0126 and the PI3K inhibitor LY294002 . The long-chain FFAs and GW9508 increased phosphorylation of ERK, Akt, and p70S6K in HASM cells and freshly isolated rat airway smooth muscle. Downregulation of FFAR1 in HASM cells by siRNA significantly attenuated oleic acid-induced phosphorylation of ERK and Akt. Oleic acid-induced ERK phosphorylation was blocked by either the Gαi-protein inhibitor pertussis toxin or U0126 and was partially inhibited by either the Gαq-specific inhibitor YM-254890 or the Gβγ signaling inhibitor gallein. Oleic acid significantly inhibited forskolin-stimulated cAMP activity, which was attenuated by pertussis toxin. Akt phosphorylation was inhibited by pertussis toxin, the ras inhibitor manumycin A, the Src inhibitor PP1, or LY294002 . Phosphorylation of p70S6K by oleic acid or GW9508 was significantly inhibited by LY294002 , U0126, and the mammalian target of rapamycin (mTOR) inhibitor rapamycin. In conclusion, the FFAR1 promoted airway smooth muscle cell proliferation and p70S6K phosphorylation through MEK/ERK and PI3K/Akt signaling pathways.