Common Signaling Pathways Research Articles

Early metabolic impairment as a contributor to neurodegenerative disease: Mechanisms and potential pharmacological intervention.

The metabolic syndrome comprises a family of clinical and laboratory findings, including insulin resistance, hyperglycemia, hypertriglyceridemia, low high-density lipoprotein cholesterol levels, and hypertension, in addition to central obesity. The syndrome confers a high risk of cardiovascular mortality. Indeed, metabolic dysfunction has been shown to cause a direct insult to smooth muscle and endothelial components of the vasculature, which leads to vascular dysfunction and hyperreactivity. This, in turn, causes cerebral vasoconstriction and hypoperfusion, eventually contributing to cognitive deficits. Moreover, the metabolic syndrome disrupts key homeostatic processes in the brain, including apoptosis, autophagy, and neurogenesis. Impairment of such processes in the context of metabolic dysfunction has been implicated in the pathogenesis of neurodegenerative diseases, including Alzheimer, Parkinson, and Huntington diseases. The aim of this review is to elucidate the role that the metabolic syndrome plays in the pathogenesis of the latter disorders, with a focus on the role of perivascular adipose inflammation in the peripheral-to-central transduction of the inflammatory insult. This review delineates common signaling pathways that contribute to these pathologies. Moreover, the role of therapeutic agents aimed at treating the metabolic syndrome, as well as their risk factors that interfere with the aforementioned pathways, are discussed as potential interventions for neurodegenerative diseases.

Quantitative Proteomics at Early Stages of the Symbiotic Interaction Between Oryza sativa and Nostoc punctiforme Reveals Novel Proteins Involved in the Symbiotic Crosstalk.

Symbiosis between cyanobacteria and plants is considered pivotal for biological nitrogen deposition in terrestrial ecosystems. Despite extensive knowledge of the ecology of plant-cyanobacterium symbioses, little is known about the molecular mechanisms involved in recognition between partners. Here, we conducted a quantitative sequential window acquisition of all theoretical fragment ion spectra mass spectrometry pipeline to analyze protein changes in Oryza sativa and Nostoc punctiforme during early events of symbiosis. We found differentially expressed proteins in both organisms linked to several biological functions, including signal transduction, adhesion, defense-related proteins and cell wall modification. In N. punctiforme we found increased expression of 62 proteins that have been previously described in other Nostoc-plant symbioses, reinforcing the robustness of our study. Our findings reveal new proteins activated in the early stages of the Nostoc-Oryza symbiosis that might be important for the recognition between the plant and the host. Oryza mutants in genes in the common symbiosis signaling pathway (CSSP) show reduced colonization efficiency, providing first insights on the involvement of the CSSP for the accommodation of N. punctiforme inside the plant cells. This information may have long-term implications for a greater understanding of the symbiotic interaction between Nostoc and land plants.

Mechanisms underlying the activity of paederus in hepatocellular carcinoma: A network pharmacology and in vitro validation approach

Paederus, belonging to the Coleoptera and Staphylinidae, can prevent cell mitosis and inhibit tumors. However, few studies exist on the mechanism of Paederus on inhibiting the growth of tumors. Consequently, the present study used network pharmacology, molecular docking and in vitro experiments explore the anti-Hepatocellular Carcinoma (HCC) mechanism of Paederus. MethodsNetwork pharmacology was used to predict the potential mechanisms through which Paederus acts against HCC. Therefore, the active compounds of Paederus were retrieved from the CNKI, Wanfang, PubMed and Web of Science databases. The targets for the active compounds were obtained from the Targetnet database, then the common targets and signaling pathways were obtained by Protein-protein interaction (PPI) network analysis, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. Thereafter, the compound-target and target-pathway networks were constructed. Finally, in vitro experiments using the SMMC-7721 HCC cells were used to further verify the predicted anti-HCC mechanism of Paederus. ResultsThe study screened 40 active compounds from Paederus, and 26 targets related to the anti-HCC mechanism of Paederus were predicted through network pharmacology. These targets were involved in the Nod-like receptor, MAPK, PI3K- Akt, TNF and AMPK signaling pathways. In addition, cell experiments showed that Paederus reduce the proliferation rate of SMMC-7721 HCC cells. Moreover, Paederus could down-regulated the expressions of the HSP90AA1, IRAK-4 and CTSB proteins in the Nod-like receptor signaling pathways in SMMC-7721 HCC cells. ConclusionThe study revealed the potential mechanism through which Paederus acts against HCC by combining network pharmacology, molecular docking, and experimental verification.

Potential Mechanisms for Why Not All Antipsychotics Are Able to Occupy Dopamine D3 Receptors in the Brain in vivo.

Dysfunctions of the dopaminergic system are believed to play a major role in the core symptoms of schizophrenia such as positive, negative, and cognitive symptoms. The first line of treatment of schizophrenia are antipsychotics, a class of medications that targets several neurotransmitter receptors in the brain, including dopaminergic, serotonergic, adrenergic and/or muscarinic receptors, depending on the given agent. Although the currently used antipsychotics display in vitro activity at several receptors, majority of them share the common property of having high/moderate in vitro affinity for dopamine D2 receptors (D2Rs) and D3 receptors (D3Rs). In terms of mode of action, these antipsychotics are either antagonist or partial agonist at the above-mentioned receptors. Although D2Rs and D3Rs possess high degree of homology in their molecular structure, have common signaling pathways and similar in vitro pharmacology, they have different in vivo pharmacology and therefore behavioral roles. The aim of this review, with summarizing preclinical and clinical evidence is to demonstrate that while currently used antipsychotics display substantial in vitro affinity for both D3Rs and D2Rs, only very few can significantly occupy D3Rs in vivo. The relative importance of the level of endogenous extracellular dopamine in the brain and the degree of in vitro D3Rs receptor affinity and selectivity as determinant factors for in vivo D3Rs occupancy by antipsychotics, are also discussed.

Model Organisms and Systems in Life Sciences

Approximately 6-7% of newborns have congenital anomalies. The causes of these anomalies are genetic-based, environmental, or multifactorial. The cause of almost 50% of congenital anomalies is not fully known. There are many specific birth defects as part of the syndromes. Even though the syndromes are complex, they use common signaling pathways in the developmental process. Because of the complex nature of developmental disorders, different types of model systems are necessary to understand the molecular pathogenesis of diseases. The molecular infrastructure of diseases and problems in a developmental process is revealed with different types of model systems. While studying the development of multicellular organisms, related molecular and cellular processes are examined. While conducting these studies, model organisms, organoids, and computerized (in silico) models are used. Each method has its advantages and disadvantages. In this review, we will provide recent knowledge on the advantages and disadvantages of modeling systems used to understand developmental processes.

Oncogenic Pathways in Neurodegenerative Diseases.

Cancer and neurodegenerative diseases are two of the leading causes of premature death in modern societies. Their incidence continues to increase, and in the near future, it is believed that cancer will kill more than 20 million people per year, and neurodegenerative diseases, due to the aging of the world population, will double their prevalence. The onset and the progression of both diseases are defined by dysregulation of the same molecular signaling pathways. However, whereas in cancer, these alterations lead to cell survival and proliferation, neurodegenerative diseases trigger cell death and apoptosis. The study of the mechanisms underlying these opposite final responses to the same molecular trigger is key to providing a better understanding of the diseases and finding more accurate treatments. Here, we review the ten most common signaling pathways altered in cancer and analyze them in the context of different neurodegenerative diseases such as Alzheimer’s (AD), Parkinson’s (PD), and Huntington’s (HD) diseases.

AllergoOncology: Danger signals in allergology and oncology: AEuropean Academy of Allergy and Clinical Immunology (EAACI) Position Paper.

The immune system interacts with many nominal ‘danger’ signals, endogenous danger‐associated (DAMP), exogenous pathogen (PAMP) and allergen (AAMP)‐associated molecular patterns. The immune context under which these are received can promote or prevent immune activating or inflammatory mechanisms and may orchestrate diverse immune responses in allergy and cancer. Each can act either by favouring a respective pathology or by supporting the immune response to confer protective effects, depending on acuity or chronicity. In this Position Paper under the collective term danger signals or DAMPs, PAMPs and AAMPs, we consider their diverse roles in allergy and cancer and the connection between these in AllergoOncology. We focus on their interactions with different immune cells of the innate and adaptive immune system and how these promote immune responses with juxtaposing clinical outcomes in allergy and cancer. While danger signals present potential targets to overcome inflammatory responses in allergy, these may be reconsidered in relation to a history of allergy, chronic inflammation and autoimmunity linked to the risk of developing cancer, and with regard to clinical responses to anti‐cancer immune and targeted therapies. Cross‐disciplinary insights in AllergoOncology derived from dissecting clinical phenotypes of common danger signal pathways may improve allergy and cancer clinical outcomes.

Inhibition of Axl Promotes the Therapeutic Effect of Targeted Inhibition of the PI3K/Akt Pathway in NRAS Mutant Melanoma Cells

Melanoma is a malignant tumor produced by highly aggressive and metastatic melanocytes. NRAS mutation is a relatively common mutation in melanoma cells. Mitogen-activated protein kinase (MAPK) signaling pathway and the PI3K/Akt pathway in melanoma cells are relatively common signaling pathways. In this study, we investigated the effect of inhibition of Axl expression on the targeted inhibition of the PI3K/Akt pathway in NRAS-mutant melanoma cells. In this study, immunohistochemistry and western blot methods were used to detect the expression of Axl and Akt proteins in melanoma cells. Axl inhibitor was added, and it detected the inhibitory efficiency of Akt inhibitor in melanoma cells. Finally, a melanoma mouse model was established, and it detected the proliferation and apoptosis of mouse tumor cells induced by Axl inhibitor and Akt inhibitor. The results showed that Axl and Akt were highly expressed in NRAS-mutant melanoma cells, and stimulation of Axl expression could reduce the inhibitory effect of Akt inhibitor on melanoma cells. The addition of Axl inhibitor can synergistically promote the effect of Akt inhibitor, slow down the proliferation of tumor cells, and induce cell apoptosis. According to the experiment in this study, Axl inhibitor combined with Akt inhibitor has a stronger therapeutic effect on melanoma than Akt inhibitor alone.

Pick the best of both glucose and lipid metabolism.

Isthmin-1 is an adipokine that has a potent glucose-lowering effect by stimulating a common intracellular signaling pathway with insulin through a distinct receptor and has an inhibitory effect on lipogenesis in the liver, whereas insulin has the opposite effect. Isthmin-1 is expected to have clinical benefits in the treatment of diabetes.

Interleukins 4 and 13 in Asthma: Key Pathophysiologic Cytokines and Druggable Molecular Targets.

Interleukins (IL)-4 and -13 play a pivotal role in the pathobiology of type-2 asthma. Indeed, IL-4 is crucially involved in Th2 cell differentiation, immunoglobulin (Ig) class switching and eosinophil trafficking. IL-13 cooperates with IL-4 in promoting IgE synthesis, and also induces nitric oxide (NO) production, goblet cell metaplasia and fibroblast proliferation, as well as elicits contractile responses and hyperplasia of airway smooth muscle cells.IL-4 and IL-13 share common signaling pathways, activated by the binding of both cytokines to receptor complexes including the α-subunit of the IL-4 receptor (IL-4Rα). Therefore, the subsequent receptor dimerization is responsible for the pathophysiologic effects of IL-4 and IL-13. By selectively blocking IL-4Rα, the fully human IgG4 monoclonal antibody dupilumab behaves as a dual receptor antagonist of both IL-4 and IL-13. Through this mechanism of action, dupilumab exerts effective therapeutic actions in type-2 inflammation, thus decreasing asthma exacerbations, FeNO (fractional exhaled NO) levels, and the intake of oral corticosteroids (OCS). In addition to being approved for the add-on biological therapy of severe asthma, dupilumab has also been licensed for the treatment of nasal polyposis and atopic dermatitis.

Beneficial Effects of Dietary Nitrite on a Model of Nonalcoholic Steatohepatitis Induced by High-Fat/High-Cholesterol Diets in SHRSP5/Dmcr Rats: A Preliminary Study.

Nonalcoholic steatohepatitis (NASH) is a chronic liver disease that leads to liver cirrhosis and hepatocellular carcinoma. Endothelial dysfunction caused by hepatic lipotoxicity is an underlying NASH pathology observed in the liver and the cardiovascular system. Here, we evaluated the effect of dietary nitrite on a rat NASH model. Stroke-prone, spontaneously hypertensive 5/Dmcr rats were fed a high-fat/high-cholesterol diet to develop the NASH model, with nitrite or captopril (100 mg/L, each) supplementation in drinking water for 8 weeks. The effects of nitrite and captopril were evaluated using immunohistochemical analyses of the liver and heart tissues. Dietary nitrite suppressed liver fibrosis in the rats by reducing oxidative stress, as measured using the protein levels of nicotinamide adenine dinucleotide phosphate oxidase components and inflammatory cell accumulation in the liver. Nitrite lowered the blood pressure in hypertensive NASH rats and suppressed left ventricular chamber enlargement. Similar therapeutic effects were observed in a captopril-treated rat NASH model, suggesting the possibility of a common signaling pathway through which nitrite and captopril improve NASH pathology. In conclusion, dietary nitrite attenuates the development of NASH with cardiovascular involvement in rats and provides an alternative NASH therapeutic strategy.

Placenta crucially affects formation of fetal congenital heart disease

It has been increasingly recognized that structural abnormalities and functional changes in the placenta can adversely affect developing fetal heart. In this article, we examine a role of the placenta as well as potential impact of placental insufficiency on a fetus with congenital heart disease (CHD). The fetal heart and placenta are directly connected because they develop simultaneously with common regulatory and signaling pathways. Moreover, placenta-associated complications are more common in pregnant women carrying fetus with CHD, and the fetal response to placental insufficiency may lead to postnatal preservation of remodeled heart. The mechanisms underlying this placenta–fetus axis potentially consists of genetic factors, oxidative stress, chronic hypoxia, and/or angiogenic imbalance. Thus, the mother–placenta–fetus circulation is critical in understanding the CHD formation. It is necessary to study the changing factors involved in these processes for early identification, imaging, quantification of placental insufficiency, and development of new prenatal therapies in the CHD patient population.

Colonization of Mutualistic Mycorrhizal and Parasitic Blast Fungi Requires OsRAM2-Regulated Fatty Acid Biosynthesis in Rice.

Arbuscular mycorrhizal (AM) fungi form a mutual association with the majority of land plants, including most angiosperms of the dicotyledon and monocotyledon lineages. The symbiosis is based upon bidirectional nutrient exchange between the host and symbiont that occurs between inner cortical cells of the root and branched AM hyphae called arbuscules that develop within these cells. Lipid transport and its regulation during the symbiosis have been intensively investigated in dicotyledon plants, especially legumes. Here, we characterize OsRAM2 and OsRAM2L, homologs of Medicago truncatula RAM2, and found that plants defective in OsRAM2 were unable to be colonized by AM fungi and showed impaired colonization by Magnaporthe oryzae. The induction of OsRAM2 and OsRAM2L is dependent on OsRAM1 and the common symbiosis signaling pathway pathway genes CCaMK and CYCLOPS, while overexpression of OsRAM1 results in increased expression of OsRAM2 and OsRAM2L. Collectively, our data show that the function and regulation of OsRAM2 is conserved in monocot and dicot plants and reveals that, similar to mutualistic fungi, pathogenic fungi have recruited RAM2-mediated fatty acid biosynthesis to facilitate invasion.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Phosphatidylserine liposomes containing curcumin inhibit bone loss in osteoporotic rats: A possible synergy through a common signaling pathway.

The present study aimed to investigate the effect of phosphatidylserine liposomes containing curcumin (PSLs-Cur) on the development of osteoporosis induced by glucocorticoids (GCs) in the rat model. PSL-Cur, phosphatidylserine (PSL), curcumin (Cur), and alendronate (AL) drugs as a positive control were administrated orally to evaluate the beneficial effects of 3-week treatments on osteoporotic rats. The biochemical and biomechanical properties of bone parameters as well as gene expression were evaluated in treated rats. Moreover, histomorphometric examinations were performed on the bone tissues of the animals. The results revealed that PSL-Cur oral administration caused a significant improvement in serum markers, mechanical strength, and OPG gene expression rather than PSL or Cur administration in osteoporotic rats. Also, PSL-Cur significantly increased the thickness and volume of cortical and trabecular bone mass in comparison with the untreated osteoporotic group. The results of this study indicated that PSL-Cur had a more inhibitory effect on bone loss induced by GCs compared to AL standard drug. Our findings suggested that PSL-loaded Cur may be an appropriate alternative therapy for glucocorticoid-induced osteoporosis. PRACTICAL APPLICATIONS: Osteoporosis is one of the most serious metabolic chronic diseases that causes fragile bone due to decreased mineral density and microarchitectural deterioration in humans. The osteoprotective effects of curcumin and phosphatidylserine, as a food spice and supplementary diet, respectively, have been shown, previously. However, the low bioavailability of curcumin (Cur) due to its poor absorption, rapid metabolism, and fast systemic elimination, limits its benefits. This deficit can be modified with phosphatidylserine liposome (PSL) formulation that facilitates the gastrointestinal delivery of Cur. Moreover, PSL is known as an osteoprotective agent that may make synergy effect with Cur against GC-induced osteoporosis. In this study, daily oral administration of phosphatidylserine liposomes containing curcumin (PSL-Cur) for 3weeks, considerably improved biochemical, biomechanical, and gene expression of bone parameters in the treated animals subjected to osteoporosis. PSL-Cur can significantly increase the thickness and volume of cortical and trabecular bone mass as well as the mechanical bone strength in animals. Experimental findings proposed PSL-Cur consumption as a proper and safe supplementary medication in the controlling of bone loss in patients with a high risk of osteoporosis.

A New Perspective on Thyroid Hormones: Crosstalk with Reproductive Hormones in Females.

Accumulating evidence has shown that thyroid hormones (THs) are vital for female reproductive system homeostasis. THs regulate the reproductive functions through thyroid hormone receptors (THRs)-mediated genomic- and integrin-receptor-associated nongenomic mechanisms, depending on TH ligand status and DNA level, as well as transcription and extra-nuclear signaling transduction activities. These processes involve the binding of THs to intracellular THRs and steroid hormone receptors or membrane receptors and the recruitment of hormone-response elements. In addition, THs and other reproductive hormones can activate common signaling pathways due to their structural similarity and shared DNA consensus sequences among thyroid, peptide, and protein hormones and their receptors, thus constituting a complex and reciprocal interaction network. Moreover, THs not only indirectly affect the synthesis, secretion, and action of reproductive hormones, but are also regulated by these hormones at the same time. This crosstalk may be one of the pivotal factors regulating female reproductive behavior and hormone-related diseases, including tumors. Elucidating the interaction mechanism among the aforementioned hormones will contribute to apprehending the etiology of female reproductive diseases, shedding new light on the treatment of gynecological disorders.

Ischemia-Reperfusion Injury and Immunosuppressants Promote Polyomavirus Replication Through Common Molecular Mechanisms.

BackgroundBK polyomavirus (BKPyV)-associated nephropathy (BKPyVAN) causes renal allograft dysfunction and graft loss. However, the mechanism of BKPyV replication after kidney transplantation is unclear. Clinical studies have demonstrated that immunosuppressants and renal ischemia–reperfusion injury (IRI) are risk factors for BKPyV infection. Studying the pathogenic mechanism of BKPyV is limited by the inability of BKPyV to infect the animal. Mouse polyomavirus (MPyV) is a close homolog of BKPyV. We used a model of MPyV infection to investigate the core genes and underlying mechanism of IRI and immunosuppressants to promote polyomavirus replication.Materials and MethodsOne-day-old male C57BL/6 mice were intraperitoneally injected with MPyV. At week 9 post-infection, all mice were randomly divided into IRI, immunosuppressant, and control groups and treated accordingly. IRI was established by clamping the left renal pedicle. Subsequently, kidney specimens were collected for detecting MPyV DNA, histopathological observation, and high-throughput RNA sequencing. Weighted gene correlation network analysis (WGCNA), protein–protein interaction network analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to screen for core genes and common signaling pathways involved in promoting MPyV replication by IRI and immunosuppressants.ResultsAfter primary infection, MPyV established persistent infection in kidneys and subsequently was significantly increased by IRI or immunosuppressant treatment individually. In the IRI group, viral loads peaked on day 3 in the left kidney, which were significantly higher than those in the right kidney and the control group. In the immunosuppressant group, viral loads in the left kidney were significantly increased on day 3, which were significantly higher than those in the control group. Protein–protein interaction network analysis and WGCNA screened complement C3, epidermal growth factor receptor (EGFR), and FN1 as core genes. Pathway enrichment analysis based on the IRI- or immunosuppressant-related genes selected by WGCNA indicated that the NF-κB signaling pathway was the main pathway involved in promoting MPyV replication. The core genes were further confirmed using published datasets GSE47199 and GSE75693 in human polyomavirus-associated nephropathy.ConclusionsOur study demonstrated that IRI and immunosuppressants promote polyomavirus replication through common molecular mechanisms. In future studies, knockdown or specific inhibition of C3, EGFR, FN1, and NF-κB signaling pathway will further validate their critical roles in promoting polyomavirus replication.

Targeting the IGF/PI3K/mTOR pathway and AXL/YAP1/TAZ pathways in primary bone cancer

Primary bone cancers (PBC) belong to the family of mesenchymal tumors classified based on their cellular origin, extracellular matrix, genetic regulation, and epigenetic modification. The three major PBC types, Ewing sarcoma, osteosarcoma, and chondrosarcoma, are frequently aggressive tumors, highly metastatic, and typically occur in children and young adults. Despite their distinct origins and pathogenesis, these sarcoma subtypes rely upon common signaling pathways to promote tumor progression, metastasis, and survival. The IGF/PI3K/mTOR and AXL/YAP/TAZ pathways, in particular, have gained significant attention recently given their ties to oncogenesis, cell fate and differentiation, metastasis, and drug resistance. Naturally, these pathways – and their protein constituents – have caught the eye of the pharmaceutical industry, and a wide array of small molecule inhibitors and antibody drug-conjugates have emerged. Here, we review how the IGF/PI3K/mTOR and AXL/YAP/TAZ pathways promote PBC and highlight the drug candidates under clinical trial investigation.

The Ribosomal Protein L5 Functions During Xenopus Anterior Development Through Apoptotic Pathways.

Ribosomal biogenesis is a fundamental process necessary for cell growth and division. Ribosomal protein L5 (Rpl5) is part of the large ribosomal subunit. Mutations in this protein have been associated with the congenital disease Diamond Blackfan anemia (DBA), a so called ribosomopathy. Despite of the ubiquitous need of ribosomes, clinical manifestations of DBA include tissue-specific symptoms, e.g., craniofacial malformations, eye abnormalities, skin pigmentation failure, cardiac defects or liver cirrhosis. Here, we made use of the vertebrate model organism Xenopus laevis and showed a specific expression of rpl5 in the developing anterior tissue correlating with tissues affected in ribosomopathies. Upon Rpl5 knockdown using an antisense-based morpholino oligonucleotide approach, we showed different phenotypes affecting anterior tissue, i.e., defective cranial cartilage, malformed eyes, and microcephaly. Hence, the observed phenotypes in Xenopus laevis resemble the clinical manifestations of DBA. Analyses of the underlying molecular basis revealed that the expression of several marker genes of neural crest, eye, and brain are decreased during induction and differentiation of the respective tissue. Furthermore, Rpl5 knockdown led to decreased cell proliferation and increased cell apoptosis during early embryogenesis. Investigating the molecular mechanisms underlying Rpl5 function revealed a more than additive effect between either loss of function of Rpl5 and loss of function of c-Myc or loss of function of Rpl5 and gain of function of Tp53, suggesting a common signaling pathway of these proteins. The co-injection of the apoptosis blocking molecule Bcl2 resulted in a partial rescue of the eye phenotype, supporting the hypothesis that apoptosis is one main reason for the phenotypes occurring upon Rpl5 knockdown. With this study, we are able to shed more light on the still poorly understood molecular background of ribosomopathies.

Capsaicin and Zinc Promote Glucose Uptake in C2C12 Skeletal Muscle Cells through a Common Calcium Signalling Pathway.

Capsaicin and zinc have recently been highlighted as potential treatments for glucose metabolism disorders; however, the effect of these two natural compounds on signalling pathways involved in glucose metabolism is still uncertain. In this study, we assessed the capsaicin- or zinc- induced activation of signalling molecules including calcium/calmodulin-dependent protein kinase 2 (CAMKK2), cAMP-response element-binding protein (CREB), and target of rapamycin kinase complex 1 (TORC1). Moreover, the expression status of genes associated with the control of glucose metabolism was measured in treated cells. The activation of cell signalling proteins was then evaluated in capsaicin- or zinc treated cells in the presence or absence of cell-permeant calcium chelator (BAPTA-AM) and the CAMKK inhibitor (STO-609). Finally, capsaicin- and zinc-induced glucose uptake was measured in the cells pre-treated with or without BAPTA-AM. Our results indicate that calcium flux induced by capsaicin or zinc led to activation of calcium signalling molecules and promoting glucose uptake in skeletal muscle cells. Pharmacological inhibition of CAMKK diminished activation of signalling molecules. Moreover, we observed an increase in intracellular cAMP levels in the cells after treatment with capsaicin and zinc. Our data show that capsaicin and zinc mediate glucose uptake in C2C12 skeletal muscle cells through the activation of calcium signalling.

PACAP-38 Induces Transcriptomic Changes in Rat Trigeminal Ganglion Cells Related to Neuroinflammation and Altered Mitochondrial Function Presumably via PAC1/VPAC2 Receptor-Independent Mechanism.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a broadly expressed neuropeptide which has diverse effects in both the peripheral and central nervous systems. While its neuroprotective effects have been shown in a variety of disease models, both animal and human data support the role of PACAP in migraine generation. Both PACAP and its truncated derivative PACAP(6-38) increased calcium influx in rat trigeminal ganglia (TG) primary sensory neurons in most experimental settings. PACAP(6-38), however, has been described as an antagonist for PACAP type I (known as PAC1), and Vasoactive Intestinal Polypeptide Receptor 2 (also known as VPAC2) receptors. Here, we aimed to compare the signaling pathways induced by the two peptides using transcriptomic analysis. Rat trigeminal ganglion cell cultures were incubated with 1 µM PACAP-38 or PACAP(6-38). Six hours later RNA was isolated, next-generation RNA sequencing was performed and transcriptomic changes were analyzed to identify differentially expressed genes. Functional analysis was performed for gene annotation using the Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome databases. We found 200 common differentially expressed (DE) genes for these two neuropeptides. Both PACAP-38 and PACAP(6-38) treatments caused significant downregulation of NADH: ubiquinone oxidoreductase subunit B6 and upregulation of transient receptor potential cation channel, subfamily M, member 8. The common signaling pathways induced by both peptides indicate that they act on the same target, suggesting that PACAP activates trigeminal primary sensory neurons via a mechanism independent of the identified and cloned PAC1/VPAC2 receptor, either via another target structure or a different splice variant of PAC1/VPAC2 receptors. Identification of the target could help to understand key mechanisms of migraine.