PKC Signaling Pathways Research Articles

An Ingenane-Type Diterpene from Euphorbia kansui Promoted Cell Apoptosis and Macrophage Polarization via the Regulation of PKC Signaling Pathways.

Euphorbia kansui, a toxic Chinese medicine used for more than 2000 years, has the effect of "purging water to promote drinking" and "reducing swelling and dispersing modules". Diterpenes and triterpenes are the main bioactive components of E. kansui. Among them, ingenane-type diterpenes have multiple biological activities as a protein kinase C δ (PKC-δ) activator, which have previously been shown to promote anti-proliferative and pro-apoptotic effects in several human cancer cell lines. However, the activation of PKC subsequently promoted the survival of macrophages. Recently, we found that 13-hydroxyingenol-3-(2,3-dimethylbutanoate)-13-dodecanoate (compound A) from E. kansui showed dual bioactivity, including the inhibition of tumor-cell-line proliferation and regulation of macrophage polarization. This study identifies the possible mechanism of compound A in regulating the polarization state of macrophages, by regulating PKC-δ-extracellular signal regulated kinases (ERK) signaling pathways to exert anti-tumor immunity effects in vitro, which might provide a new treatment method from the perspective of immune cell regulation.

Metabolomic Effects of Liraglutide Therapy on the Plasma Metabolomic Profile of Patients with Obesity.

Liraglutide, a long-acting glucagon-like peptide-1 receptor agonist (GLP1RA), is a well-established anti-diabetic drug, has also been approved for the treatment of obesity at a dose of 3 mg. There are a limited number of studies in the literature that have looked at changes in metabolite levels before and after liraglutide treatment in patients with obesity. To this end, in the present study we aimed to explore the changes in the plasma metabolomic profile, using liquid chromatography-high resolution mass spectrometry (LC-HRMS) in patients with obesity. A single-center prospective study was undertaken to evaluate the effectiveness of 3 mg liraglutide therapy in twenty-three patients (M/F: 8/15) with obesity, mean BMI 40.81 ± 5.04 kg/m2, and mean age of 36 ± 10.9 years, in two groups: at baseline (pre-treatment) and after 12 weeks of treatment (post-treatment). An untargeted metabolomic profiling was conducted in plasma from the pre-treatment and post-treatment groups using LC-HRMS, along with bioinformatics analysis using ingenuity pathway analysis (IPA). The metabolomics analysis revealed a significant (FDR p-value ≤ 0.05, FC 1.5) dysregulation of 161 endogenous metabolites (97 upregulated and 64 downregulated) with distinct separation between the two groups. Among the significantly dysregulated metabolites, the majority of them were identified as belonging to the class of oxidized lipids (oxylipins) that includes arachidonic acid and its derivatives, phosphorglycerophosphates, N-acylated amino acids, steroid hormones, and bile acids. The biomarker analysis conducted using MetaboAnalyst showed PGP (a21:0/PG/F1alpha), an oxidized lipid, as the first metabolite among the list of the top 15 biomarkers, followed by cysteine and estrone. The IPA analysis showed that the dysregulated metabolites impacted the pathway related to cell signaling, free radical scavenging, and molecular transport, and were focused around the dysregulation of NF-κB, ERK, MAPK, PKc, VEGF, insulin, and pro-inflammatory cytokine signaling pathways. The findings suggest that liraglutide treatment reduces inflammation and modulates lipid metabolism and oxidative stress. Our study contributes to a better understanding of the drug's multifaceted impact on overall metabolism in patients with obesity.

Gα3 regulates growth and development, stress response, patulin synthesis and pathogenicity of Penicillium expansum by mediating cAMP/PKA and PKC signaling

G proteins are signaling proteins in eukaryotes that transduce extracellular signals into the intracellular space. There are three classes of Gα proteins in fungi, among which class III Gα proteins play crucial roles for fungal growth, secondary metabolism, and pathogenicity. In this study, we found that the Gα3 protein from Penicillium expansum belongs to the P-loop NTPase superfamily and contains a G-alpha conserved domain and an adenylate cyclase binding site that can bind to guanine nucleotides. Deletion of Gα3 downregulated the expression of the cAMP/PKA signaling pathway genes AC, PkaC, and PkaR, and the PKC signaling related genes PKC1, PKC2, and PLC of P. expansum. The Gα3-deleted strain showed slow colony growth, irregular depression at the colony edge, and increased branching at the mycelial tip. Gα3 deletion decreased spore production, inhibited spore germination, and reduced the expression levels of genes that regulate conidiospore formation, including abaA, wetA, vosA and brlA. In addition, the Gα3-deleted strain grew faster in carbon and NO3- medium, and was more sensitive to salt and oxidative stress, but less sensitive to cell wall stress. Gα3 deletion significantly downregulated the expression of patulin biosynthesis-related genes except for PatF and PatM, and reduced the patulin levels in vivo and in vitro. In addition, loss of Gα3 reduced the pathogenicity of the strain on fruit, with down-regulated expression of the extracellular enzyme genes PG, PL, and PLA. In conclusion, Gα3 can regulate growth and development, carbon and nitrogen response, stress response, patulin biosynthesis and pathogenicity by mediating cAMP/PKA and PKC signaling pathways of P. expansum.

Unveiling the antinociceptive mechanisms of Methyl-2-(4-chloro-phenyl)-5-benzoxazoleacetate: insights from nociceptive assays in mice.

Methyl-2-(4-chloro- phenyl)-5-benzoxazoleacetate (MCBA), a synthetic benzoxazole derivative with established antipsoriatic efficacy, was investigated for potential antinociceptive effects. This study employs various nociceptive assays in mice to elucidate MCBA's antinociceptive mechanisms. MCBA's antinociceptive potential was tested against various nociception models induced by formalin, glutamate, capsaicin, a transient receptor potential vanilloid 1 (TRPV1) receptor agonist, and phorbol 12-myristate 13-acetate, a protein kinase C (PKC) activator. It was then assessed using the hot plate test and examined within the acetic acid-induced writhing test. During the acetic acid-induced writhing test, MCBA was pre-challenged against selective receptor antagonists such as naloxone, caffeine, atropine, yohimbine, ondansetron, and haloperidol. It was also pre-challenged with ATP-sensitive potassium channel inhibitor (glibenclamide) to further elucidate its antinociceptive mechanism. The results showed that oral administration of MCBA led to a dose-dependent and significant inhibition (p < 0.05) of nociceptive effects across all evaluated models at doses of 60, 120, and 240 mg/kg. Moreover, the efficacy of MCBA's antinociceptive potential was significantly counteracted (p < 0.0001) by specific antagonists: (i) directed at adenosinergic, alpha-2 adrenergic, and cholinergic receptors using caffeine, yohimbine, and atropine, respectively; and (ii) targeting ATP-sensitive potassium channels, employing glibenclamide. Antagonists aimed at opioidergic and serotoninergic receptors (naloxone and ondansetron, respectively) had poor utility in inhibiting antinociceptive activity. Conversely, the dopaminergic receptor antagonist haloperidol potentiated locomotor abnormalities associated with MCBA treatment. MCBA-induced antinociception involves modulation of glutamatergic-, TRVP1 receptors- and PKC-signaling pathways. It impacts adenosinergic, alpha-2 adrenergic, and cholinergic receptors and opens ATP-sensitive potassium channels.

Label-free quantitative proteomic profiling reveals differential plasma protein expression in patients with obesity after treatment with liraglutide.

Treatment and management of obesity is clinically challenging. The inclusion of GLP-1 receptor agonists (GLP1RA) in the medical management of obesity has proven to be efficacious. However, mechanisms underlying the molecular changes arising from GLP1RA treatment in patients with obesity remain to be elucidated. A single-center, prospective study was undertaken to evaluate the changes in the plasma proteins after liraglutide 3 mg therapy in twenty patients (M/F: 7/13) with obesity (mean BMI 40.65 ± 3.7 kg/m2). Anthropometric and laboratory parameters were measured, and blood samples were collected at two time points: baseline, before initiating treatment (pretreatment group, PT), and after three months of receiving the full dose liraglutide 3 mg (posttreatment group, PoT). An untargeted label-free LC MSMS mass spectrometric approach combined with bioinformatics and network pathway analysis was used to determine changes in the proteomic profiles. The mean age of the study participants was 36.0 ± 11.1 years. A statistically significant change was observed in weight, BMI and HbA1c levels between the PT and PoT groups (paired t-test, P < 0.001). A significant dysregulation was noted in the abundances of 151 proteins (31 up and 120 downregulated) between the two groups. The potential biomarkers were evaluated using receiver operating characteristic (ROC) curves. The top ten proteins (area under the curve (AUC) of 0.999 (95% CI)) were identified as potential biomarkers between PT and PoT groups and included Cystatin-B, major vault protein, and plastin-3, which were upregulated, whereas multimerin-2, large ribosomal P2, and proline-rich acidic protein 1 were downregulated in the PoT group compared with the PT group. The top network pathway identified using ingenuity pathway analysis (IPA), centered around dysregulation of MAPK, AKT, and PKc signaling pathways and related to cell-to-cell signaling and interaction, cellular assembly and organization, cellular compromise and a score of 46 with 25 focus proteins. Through label-free quantitative proteomic analysis, our study revealed significant dysregulation of plasma proteins after liraglutide 3 mg treatment in patients with obesity. The alterations in the proteomic profile between the PT and PoT groups demonstrated a decrease in levels of proteins involved in inflammation and oxidative stress pathways. On the other hand proteins involved in the glycolytic and lipolytic metabolic pathways as well as those participating in cytoskeletal and endothelial reorganization were observed to be increased. Understanding actions of liraglutide at a molecular and proteomic levels provides a holistic look into how liraglutide impacts metabolism, induces weight loss and improves overall metabolic health.

Retracted] Isoquercitrin inhibits bladder cancer progression invitro and invivo by regulating the PI3K/Akt and PKC signaling pathways.

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that the agarose gel electrophoretic bands shown in Fig. 4A for PKC were strikingly similar to bands that had already appeared in another article written by different authors at different research institutes. Owing to the fact that the contentious data in the above article had already been published prior to its submission to Oncology Reports, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [Oncology Reports 36: 165‑172, 2016; DOI: 10.3892/or.2016.4794].

Downregulation of CRHBP is associated with trophoblast invasion inhibition in recurrent pregnancy loss.

Corticotropin-releasing hormone binding protein (CRHBP) is fundamental to the stress response and plays an important role in parturition during pregnancy. This study shows that abnormal CRHBP expression could be an early warning sign of recurrent pregnancy loss and that CRHBP knockdown could suppress HTR8/SVneo cell invasion by the PKC signaling pathway via interacting with CRH receptor 2. Trophoblast invasion is critical for placentation and pregnancy success. Trophoblast dysfunction results in many pregnancy complications, including recurrent pregnancy loss (RPL). Corticotropin-releasing hormone binding protein (CRHBP) is fundamental to the stress response and plays an important role in parturition during pregnancy via binding with CRH. To further characterize its function in early pregnancy, we explored the expression of CRHBP in villi during early pregnancy. Compared with normal pregnant women, we demonstrated that the expression of CRHBP decreased in the trophoblasts and villi in RPL patients and that knockdown of CRHBP expression could suppress HTR8/SVneo cell invasion significantly. Our further exploration indicated that the capacity of CRHBP for regulating trophoblast invasion was associated with the PKC signaling pathway via interacting with CRH receptor 2. These findings might provide a new fundamental mechanism for successful pregnancy and a new diagnostic and therapeutic target for RPL.

Dysfunctional endocannabinoid CB1 receptor expression and signaling contribute to skeletal muscle cell toxicity induced by simvastatin

Statins are the most prescribed lipid-lowering agents worldwide. Their use is generally safe, although muscular toxicity occurs in about 1 in 10.000 patients. In this study, we explored the role of the endocannabinoid system (ECS) during muscle toxicity induced by simvastatin. In murine C2C12 myoblasts exposed to simvastatin, levels of the endocannabinoids AEA and 2-AG as well the expression of specific miRNAs (in particular miR-152) targeting the endocannabinoid CB1 gene were increased in a time-dependent manner. Rimonabant, a selective CB1 antagonist, exacerbated simvastatin-induced toxicity in myoblasts, while only a weak opposite effect was observed with ACEA and GAT211, selective orthosteric and allosteric agonists of CB1 receptor, respectively. In antagomiR152-transfected myoblasts, simvastatin toxicity was in part prevented together with the functional rescue of CB1. Further analyses revealed that simvastatin in C2C12 cells also suppresses PKC and ERK signaling pathways, which are instead activated downstream of CB1 receptor stimulation, thus adding more insight into the mechanism causing CB1 functional inactivation. Importantly, simvastatin induced similar alterations in skeletal muscles of C57BL/6 J mice and primary human myoblasts. In sum, we identified the dysregulated expression of the endocannabinoid CB1 receptor as well as the impairment of its downstream signaling pathways as a novel pathological mechanism involved in statin-induced myopathy.

Wenjing Zhitong recipe exhibits potential anti-primary dysmenorrhea properties by inhibiting COX2 and PKC signaling pathway in rats induced by estradiol benzoate and oxytocin

Wenjing Zhitong recipe exhibits potential anti-primary dysmenorrhea properties by inhibiting COX2 and PKC signaling pathway in rats induced by estradiol benzoate and oxytocin

234-OR: Succinate Potentiates Insulin Secretion through SUCNR1

Here, we examined the role of succinate, a metabolite that acts by engaging the succinate receptor 1 (SUCNR1), in regulating insulin secretion by β-cells. We found that glucose increases SUCNR1 expression in β-cells and that activating SUCNR1 with either extracellular succinate or a synthetic agonist boosts glucose-stimulated insulin secretion through the Gq and PKC signaling pathways. Also, we identified that SUCNR1 is essential for preserving insulin secretion in a diet-induced insulin-resistance model. Mice with β-cell-specific SUCNR1 deficiency had impaired glucose tolerance and reduced insulin secretion when fed a high-fat diet, without changes in β-cell mass or insulin sensitivity. To investigate the physiological significance of succinate as a secretagogue in humans, we studied the potential connection between circulating succinate levels and β-cell function in response to oral and intravenous glucose challenges in a cohort of patients with impaired glucose tolerance (IGT). These patients were characterized by presenting hyperinsulinemia during both oral and intravenous glucose tests, compared to normal glucose tolerance (NGT) individuals. Moreover, succinate levels were elevated in IGT patients in response to these challenges compared to NGT patients, whereas circulating GLP-1 levels during the tests were not different between groups. Remarkably, we found that circulating succinate levels are positively correlated with insulin secretion potentiation during intravenous glucose administration, indicating that this system is activated by high glucose levels and partially regulated by the β-cell in an autocrine fashion. These findings suggest that succinate may act as a hormone, potentiating insulin secretion in humans through SUCNR1- a compensatory mechanism particularly relevant in the hyperinsulinemia elicited by insulin resistance. Our work sheds new light on the role of the succinate-SUCNR1 axis as a potential therapeutic target for improving insulin secretion in metabolic disorders. Disclosure J.Sabadell-basallote: None. J.J.Vendrell: None. S.Fernandez-veledo: None. B.D.Astiarraga: None. M.Ejarque: None. M.Repollés-de-dalmau: None. F.X.Sureda: None. D.F.De jesus: None. C.Núñez roa: None. A.Mari: Consultant; Eli Lilly and Company. R.Kulkarni: Advisory Panel; Novo Nordisk, Inversago, Biomea Fusion, Inc., REDD Pharma, Research Support; Inversago. Funding Spanish Ministry of Science and Innovation (SAF2015-65019-R, RTI2018-093919-B-100); Instituto de Salud Carlos III (FI18/00151, CP10/00438, CPII16/00008); Spanish Biomedical Research Center in Diabetes and Associated Metabolic Disorders (CB07708/0012); Catalan Association of Diabetes (PV21039S)

Simultaneously Targeting Two Coupled Signalling Molecules in the Mesenchymal Stem Cell Support Efficiently Sensitises the Multiple Myeloma Cell Line H929 to Bortezomib.

Several studies have shown that diverse components of the bone marrow (BM) microenvironment play a central role in the progression, pathophysiology, and drug resistance in multiple myeloma (MM). In particular, the dynamic interaction between BM mesenchymal stem cells (BM-MSC) and MM cells has shown great relevance. Here we showed that inhibiting both PKC and NF-κB signalling pathways in BM-MSC reduced cell survival in the MM cell line H929 and increased its susceptibility to the proteasome inhibitor bortezomib. PKC-mediated cell survival inhibition and bortezomib susceptibility induction were better performed by the chimeric peptide HKPS than by the classical enzastaurin inhibitor, probably due to its greatest ability to inhibit cell adhesion and its increased capability to counteract the NF-κB-related signalling molecules increased by the co-cultivation of BM-MSC with H929 cells. Thus, inhibiting two coupled signalling molecules in BM-MSC was more effective in blocking the supportive cues emerging from the mesenchymal stroma. Considering that H929 cells were also directly susceptible to PKC and NF-κB inhibition, we showed that treatment of co-cultures with the HKPS peptide and BAY11-7082, followed by bortezomib, increased H929 cell death. Therefore, targeting simultaneously connected signalling elements of BM-MSC responsible for MM cells support with compounds that also have anti-MM activity can be an improved treatment strategy.

The role of rhoA/rho-kinase and PKC in the inhibitory effect of L-cysteine/H2S pathway on the carbachol-mediated contraction of mouse bladder smooth muscle.

We investigated the role of RhoA/Rho-kinase (ROCK) and PKC in the inhibitory effect of L-cysteine/hydrogen sulfide (H2S) pathway on the carbachol-mediated contraction of mouse bladder smooth muscle. Carbachol (10-8-10-4M) induced a concentration-dependent contraction in bladder tissues. L-cysteine (H2S precursor; 10-2M) and exogenous H2S (NaHS; 10-3M) reduced the contractions evoked by carbachol by ~ 49 and ~ 53%, respectively, relative to control. The inhibitory effect of L-cysteine on contractions to carbachol was reversed by 10-2M PAG (~ 40%) and 10-3M AOAA (~ 55%), cystathionine-gamma-lyase (CSE) and cystathionine-β-synthase (CBS) inhibitor, respectively. Y-27632 (10-6M) and GF 109203X (10-6M), a specific ROCK and PKC inhibitor, respectively, reduced contractions evoked by carbachol (~ 18 and ~ 24% respectively), and the inhibitory effect of Y-27632 and GF 109203X on contractions was reversed by PAG (~ 29 and ~ 19%, respectively) but not by AOAA. Also, Y-27632 and GF 109203X reduced the inhibitory responses of L-cysteine on the carbachol-induced contractions (~ 38 and ~ 52% respectively), and PAG abolished the inhibitory effect of L-cysteine on the contractions in the presence of Y-27632 (~ 38%). Also, the protein expressions of CSE, CBS, and 3-MST enzymes responsible for endogenous H2S synthesis were detected by Western blot method. H2S level was increased by L-cysteine, Y-27632, and GF 109203X (from 0.12 ± 0.02 to 0.47 ± 0.13, 0.26 ± 0.03, and 0.23 ± 0.06nmol/mg respectively), and this augmentation in H2S level decreased with PAG (0.17 ± 0.02, 0.15 ± 0.03, and 0.07 ± 0.04nmol/mg respectively). Furthermore, L-cysteine and NaHS reduced carbachol-induced ROCK-1, pMYPT1, and pMLC20 levels. Inhibitory effects of L-cysteine on ROCK-1, pMYPT1, and pMLC20 levels, but not of NaHS, were reversed by PAG. These results suggest that there is an interaction between L-cysteine/H2S and RhoA/ROCK pathway via inhibition of ROCK-1, pMYPT1, and pMLC20, and the inhibition of RhoA/ROCK and/or PKC signal pathway may be mediated by the CSE-generated H2S in mouse bladder.

The combination of NlMIP and Gαi/q coupled-receptor NlA10 promotes abdominal vibration production in female Nilaparvata lugens (Stål)

For various sexually mature insects, including the brown planthopper (BPH, Nilaparvata lugens), the abdominal vibration (AV) signal is the initiation of the mating process, and it is critical to the success of mating. Currently, there are few studies on the genetic and molecular mechanisms of AV regulation. Our previous AV-related transcriptomic study in female BPH identified myoinhibitory peptide (NlMIP) as a gene that potentially affects AV status in females, but how NlMIP affects AV status remains unknown. In this study, we confirmed that NlMIP regulates AV production and mating behavior in female BPH. When the RNAi knockdown efficiency of NlMIP was 59.00%, the probability of females producing AV and the mating rate in 1 h decreased by 38.89 and 61.11%, respectively. In addition, six mature peptides of NlMIP were synthesized and they were able to regulate AV production and mating behavior in females, with NlMIP2 having the strongest effect. The A-family neuropeptide GPCR 10 (NlA10) was found to be a potential receptor for NlMIP based on a phylogenetic tree analysis and the fact that NlMIP mature peptides effectively activated NlA10. After NlA10 was knocked down, the probability of females producing AV and the mating rate in 1 h had reductions of 28.89 and 43.33%, respectively. When activated by NlMIP2, NlA10 coupled the Gαi/q signalling pathways, thereby inhibiting the downstream AC/cAMP/PKA, activating the PLC/Ca2+/PKC signalling pathways and then activating MEK1/2 in a cascade to mediate the phosphorylation of ERK1/2, and finally regulating the AV of females. These results provide a basis for the prevention and control of the brown planthopper pest by disrupting female AV.

Trigonochinene E promotes lysosomal biogenesis and enhances autophagy via TFEB/TFE3 in human degenerative NP cells against oxidative stress

BackgroundMacroautophagy (henceforth autophagy) is the major form of autophagy, which delivers intracellular cargo to lysosomes for degradation. Considerable research has revealed that the impairment of lysosomal biogenesis and autophagic flux exacerbates the development of autophagy-related diseases. Therefore, reparative medicines restoring lysosomal biogenesis and autophagic flux in cells may have therapeutic potential against the increasing prevalence of these diseases. PurposeThe aim of the present study was thus to explore the effect of trigonochinene E (TE), an aromatic tetranorditerpene isolated from Trigonostemon flavidus, on lysosomal biogenesis and autophagy and to elucidate the potential underlying mechanism. MethodsFour human cell lines, HepG2, nucleus pulposus (NP), HeLa and HEK293 cells were applied in this study. The cytotoxicity of TE was evaluated by MTT assay. Lysosomal biogenesis and autophagic flux induced by 40 μM TE were analyzed using gene transfer techniques, western blotting, real-time PCR and confocal microscopy. Immunofluorescence, immunoblotting and pharmacological inhibitors/activators were applied to determine the changes in the protein expression levels in mTOR, PKC, PERK, and IRE1α signaling pathways. ResultsOur results showed that TE promotes lysosomal biogenesis and autophagic flux by activating the transcription factors of lysosomes, transcription factor EB (TFEB) and transcription factor E3 (TFE3). Mechanistically, TE induces TFEB and TFE3 nuclear translocation through an mTOR/PKC/ROS-independent and endoplasmic reticulum (ER) stress-mediated pathway. The PERK and IRE1α branches of ER stress are crucial for TE-induced autophagy and lysosomal biogenesis. Whereas TE activated PERK, which mediated calcineurin dephosphorylation of TFEB/TFE3, IRE1α was activated and led to inactivation of STAT3, which further enhanced autophagy and lysosomal biogenesis. Functionally, knockdown of TFEB or TFE3 impairs TE-induced lysosomal biogenesis and autophagic flux. Furthermore, TE-induced autophagy protects NP cells from oxidative stress to ameliorate intervertebral disc degeneration (IVDD). ConclusionsHere, our study showed that TE can induce TFEB/TFE3-dependent lysosomal biogenesis and autophagy via the PERK-calcineurin axis and IRE1α-STAT3 axis. Unlike other agents regulating lysosomal biogenesis and autophagy, TE showed limited cytotoxicity, thereby providing a new direction for therapeutic opportunities to use TE to treat diseases with impaired autophagy-lysosomal pathways, including IVDD.

Posttreatment with dexmedetomidine aggravates LPS-induced myocardial dysfunction partly via activating cardiac endothelial α2A-AR in mice

BackgroundDexmedetomidine (DEX) administered before or at 30 min after sepsis induction was reported to alleviate septic cardiomyopathy in experimental models. However, sepsis is a life-threatening organ dysfunction due to infection-induced dysregulated host response, whether DEX treatment in the presence of organ dysfunction affects septic cardiomyopathy is unknown. This study investigated the effect of DEX posttreatment on septic cardiomyopathy. MethodsMale wild-type and α2A-adrenergic receptor (AR) knockout mice were exposed to lipopolysaccharide (LPS) or cecal ligation puncture (CLP), and cultured cardiac endothelial cells were used. Mouse survival, myocardial function, inflammatory response and related signaling pathways were determined. ResultsDEX treatment at 6, 9 h after LPS challenge significantly reduced survival rate of LPS-challenged mice, especially at 9 h. DEX administered at 9 h after LPS injection or CLP significantly reduced survival in LPS or CLP-induced sepsis in wild-type mice, but not in α2A-AR knockout mice. LPS treatment for 20 h decreased the left ventricle + dp/dt, increased myocardial interleukin (IL)-1β and IL-6 concentrations as well as cardiac endothelial tumor necrosis factor (TNF)-α, vascular cell adhesion molecule-1 (VCAM-1) and ICAM-1 expression, which were enhanced by DEX treated at 9 h after LPS injection in wild-type mice, but not in α2A-AR knockout mice. Furthermore, DEX posttreatment increased p38 phosphorylation, c-Fos nuclear translocation and VCAM-1 expression in LPS-treated cardiac endothelial cells, which were eliminated by α2A-AR knockout or PKC inhibitor. ConclusionsDEX posttreatment aggravates LPS-induced cardiac inflammation and myocardial dysfunction, at least in part, via activating cardiac endothelial α2A-AR-mediated PKC signal pathway.

Metformin relaxes rat thoracic aorta via nitric oxide, AMPK, potassium channels, and PKC.

The present research aimed to identify the functional effects and underlying mechanisms of metformin on the rat thoracic aorta. Thoracic aorta segments of Wistar Albino rats were put in the chambers of an isolated tissue bath system. The resting tone was adjusted to 1 g. Following the equilibration time, potassium chloride or phenylephrine was used to contract the vascular segments. The vessel segments were cumulatively treated with metformin (10-7-10-3 M) when a steady contraction was achieved. The described experimental approach was repeated after incubations with signaling pathway inhibitors and selective blockers of potassium channels to identify the effect mechanisms of metformin. Metformin had a potent vasorelaxant effect in a concentration-dependent way (P<0.001). After the endothelium was removed, the vasorelaxant effect level of metformin was significantly reduced. The level of vasorelaxant effect of metformin was increased by the maintenance of perivascular adipose tissue. Following administrations of L-NAME, methylene blue, compound C, BIM-I, and potassium channel blockers, the level of vasodilatory action of metformin was significantly reduced (P<0.001). According to the results of this investigation, metformin significantly relaxes the thoracic aorta segments of rats. Metformin-mediated vasorelaxation involves the activation of numerous subtypes of potassium channels, including BKCa, IKCa, Kv, Kir, and K2p channels, as well as endothelium-dependent processes, including AMPK and eNOS/NO/sGS signaling pathways. Moreover, metformin-induced vasorelaxation is mediated through PVAT activation and the PKC signaling pathway.

Glucose Uptake Is Increased by Estradiol Dipropionate in L6 Skeletal Muscle Cells

GLUT4 is an important glucose transporter, which is closely related to insulin resistance and type 2 diabetes. In this study, we investigated the mechanism of Estradiol Dipropionate (EDP) on uptake of glucose in L6 skeletal muscle cells. In our study, we confirmed that EDP promoted uptake of glucose in L6 skeletal muscle cells in both normal and insulin resistant models. Western blot indicated that EDP accelerated GLUT4 expression and significantly activated AMPK and PKC phosphorylation; the expression of GLUT4 was significantly inhibited by AMPK inhibitor compound C and PKC inhibitor Gö6983, but not by Wortmannin (Akt inhibitor). Meanwhile, EDP boosted GLUT4 expression, and also increased intracellular Ca2+ levels. In the presence of 2 mM, 0 mM extracellular Ca2+ and 0 mM extracellular Ca2+ + BAPTA-AM, the involvement of intracellular Ca2+ levels contribute to EDP-induced GLUT4 expression and fusion with plasma membrane. Therefore, this study investigated whether EDP promoted GLUT4 expression through AMPK and PKC signaling pathways, thereby enhancing GLUT4 uptake of glucose and fusion into plasma membrane in L6 skeletal muscle cells. In addition, both EDP induced GLUT4 translocation and uptake of glucose were Ca2+ dependent. These findings suggested that EDP may be potential drug for the treatment of type 2 diabetes.

Phosphatidylserine in the Nervous System: Cytoplasmic Regulator of the AKT and PKC Signaling Pathways and Extracellular "Eat-Me" Signal in Microglial Phagocytosis.

Phosphatidylserine (PtdSer) is an important anionic phospholipid found in eukaryotic cells and has been proven to serve as a beneficial factor in the treatment of neurodegenerative diseases. PtdSer resides in the inner leaflet of the plasma membrane, where it is involved in regulating the AKT and PKC signaling pathways; however, it becomes exposed to the extracellular leaflet during neurodevelopmental processes and neurodegenerative diseases, participating in microglia-mediated synaptic and neuronal phagocytosis. In this paper, we review several characteristics of PtdSer, including the synthesis and translocation of PtdSer, the functions of cytoplasmic and exposed PtdSer, and different PtdSer-detection materials used to further understand the role of PtdSer in the nervous system.

Stearic acid induces CCK and GLP-1 upregulation via GPR120/PLC-β, leading to reduced appetite in Hu sheep fed with rice straw.

Due to the poor palatability of straw, feeding untreated rice straw reduces ruminant feed intake, thus affecting the production efficiency of animal husbandry. However, the detailed mechanism by which straw affects ruminants' feed intake is unclear. Therefore, this study aimed to elucidate the molecular mechanism by which a rice straw (RS)-based diet affects appetite regulation in Hu sheep. We found that RS promoted the secretion of cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) and decreased feed intake. Blood metabolomics showed that RS activated the arachidonic acid metabolism, biosynthesis of unsaturated fatty acids, linoleic acid metabolism, and alpha-linolenic acid metabolism pathways, and the secretion of stearic acid (SA), their metabolic end product, increased significantly. GPR120, one of the classical receptors of long-chain fatty acids (LCFAs), can be involved in appetite regulation. However, the role of SA in satiety hormone regulation mediated by GPR120 in ruminants is unclear. In this study, in vivo experiments showed that in sheep fed with RS, SA increased significantly and activated GPR120/Ca2+, increasing the secretion of the satiety hormones CCK and GLP-1. In vitro mechanism studies showed that SA promotes GLP-1 and CCK secretion by activating GPR120-mediated downstream PKC and IP3R signaling pathways of PLCβ.

New insights into the role and mechanisms of ginsenoside Rg1 in the management of Alzheimer’s disease

Alzheimer's disease (AD) is a common neurodegenerative disorder in the elderly characterized by memory loss and cognitive dysfunction. The pathogenesis of AD is complex. One-targeted anti-AD drugs usually fail to delay AD progression. Traditional Chinese medicine records have documented the use of the roots of Panax ginseng (ginseng roots) and its prescriptions to treat dementia. Ginsenoside Rg1, the main ginsenoside component of ginseng roots, exhibits a certain therapeutic effect in the abovementioned diseases, suggesting its potential in the management of AD. Therefore, we combed the pathogenesis of AD and currently used anti-AD drugs, and reviewed the availability, pharmacokinetics, and pharmaceutic studies of ginsenoside Rg1. This review summarizes the therapeutic effects and mechanisms of ginsenoside Rg1 and its deglycosylated derivatives in AD in vivo and in vitro. The main mechanisms include improvement in Aβ and Tau pathologies, regulation of synaptic function and intestinal microflora, and reduction of inflammation, oxidative stress, and apoptosis. The underlying mechanisms mainly involve the regulation of PKC, MAPK, PI3K/Akt, CDK5, GSK-3β, BDNF/TrkB, PKA/CREB, FGF2/Akt, p21WAF1/CIP1, NF-κB, NLRP1, TLR3, and TLR4 signaling pathways. As the effects and underlying mechanisms of ginsenoside Rg1 on AD have not been systematically reviewed, we have provided a comprehensive review and shed light on the future directions in the utilization of ginsenoside Rg1 and ginseng roots as well as the development of anti-AD drugs.