Modulation Of JNK Research Articles

Neuroprotective Effects of Metformin on Cerebral Ischemia-Reperfusion Injury: Modulation of JNK and p38 MAP Kinase Signaling Pathways.

Cerebral ischemia-reperfusion injury (CIRI) is a significant pathological process in stroke, characterized by neuronal cell death and neurological dysfunction. Metformin, commonly used for diabetes management, has been noted for its neuroprotective properties, though its effects on CIRI and the mechanisms involved remain unclear. This study explored the neuroprotective impact of metformin on CIRI, focusing on its potential to modulate the c-Jun N-terminal kinase (JNK) and p38 MAP kinase (p38) signaling pathways. Using in vitro models of oxygen-glucose deprivation/reperfusion (OGD/R) in neuronal cells and in vivo mouse models of middle cerebral artery occlusion (MCAO), the effects of metformin were assessed. Cell viability was measured with Cell Counting Kit-8 (CCK-8), protein expression via Western Blot (WB), and apoptosis through flow cytometry. The extent of brain injury in mice was evaluated using 2,3,5-triphenyltetrazolium chloride (TTC) staining, while JNK and p38 activation statuses were detected through WB and phospho-JNK (p-JNK) immunofluorescence staining. Results showed that metformin significantly improved the viability of HT22 cells post-OGD/R, reduced apoptosis, and decreased OGD/R-induced phosphorylation of JNK and p38 in vitro. In vivo, metformin treatment notably reduced brain infarct volume in MCAO mice, inhibited p-p38 and p-JNK expression, and enhanced neurological function. These findings suggest that metformin exerts neuroprotective effects against CIRI by modulating the JNK/p38 signaling pathway, highlighting its potential therapeutic value in treating cerebral ischemia-reperfusion injury and paving the way for clinical applications.

Chitosan-enclosed SLN improved SV-induced hepatocellular cell carcinoma death by modulation of IQGAP gene expression, JNK, and HDAC activities.

Hepatocellular carcinoma (HCC) is a global life-threatening problem and therapeutic interventions are still encountered. IQGAP genes are involved in HCC oncogenesis. The modulatory effect of statins on the expression of IQGAP genes is still unclear. This study aims to study the effect of free SV and chitosan (CS) decorated simvastatin (SV) loaded solid lipid nanoparticles (C-SV-SLNs) on HCC mortality. Plain, SV-SLN, and C-SV- SLN were prepared and characterized in terms of particle size (PS), zeta potential (ZP), and polydispersity index (PDI). The biosafety of different SLN was investigated using fresh erythrocytes, moreover, cytotoxicity was investigated using HepG2 cell lines. The effect of SLNs on IQGAPs gene expression as well as JNK, HDAC6, and HDAC8 activity was investigated using PCR and MOE-docking. The current results displayed that SV-SLNs have nanosized, negative ZP and are homogenous, CS decoration shifts the ZP of SLN into cationic ZP. Furthermore, all SLNs exhibited desirable biosafety in terms of no deleterious effect on erythrocyte integrity. SV solution and SV-SLN significantly increase the mortality of HepG2 compared to undertreated cells, however, the effect of SV-SLN is more pronounced compared to free SV. Remarkably, C-SV-SLN elicits high HepG2 cell mortality compared to free SV and SV-SLN. The treatment of HepG2 cells with SV solution, SV-SLN, or C-SV-SLN significantly upregulates the IQGAP2 gene with repression of IQGAP1 and IQGAP3 genes. MOE-docking studies revealed both SV and tenivastatin exhibit interactions with the active sites of JNK, HDAC6, and HDAC8. Moreover, tenivastatin exhibited greater interactions with magnesium and zinc compared to SV. This research provides novel insights into the therapeutic potential of SV, SV-SLN and C-SV-SLNs in HCC treatment, modulating critical signaling cascades involving IQGAPs, JNK, and HDAC. The development of C-SV-SLNs presents a promising strategy for effective HCC therapy.

Discovery of Piperazin‐2‐yl‐pyrimidines as Anticancer Agents via Targeting JNK Signaling Pathway in Human MCF‐7 Breast Carcinoma

AbstractBreast cancer (BC) is the second leading cause of cancer‐related mortality in women, and targeting biological pathways such as the JNK pathway has proven to be a viable therapeutic target for BC therapy. Here, we synthesized piperazin‐2‐yl‐pyrimidines and evaluated them for anticancer activity against MCF‐7 cells. In addition, antioxidant, reactive oxygen species (ROS) inhibition, caspase activity, and toxicity in platelets were studied in the presence and absence of active compound IA‐6 or IA‐7. Our detailed experimental analysis found that the compound IA‐7 showed anticancer activity by either activating p‐JNK or by inducing radical species in cancer and thrombosis model. Evident to in vitro analysis, the structure based molecular interaction studies of binding of IA‐7 to JNK3S exhibited a significant binding energy of −7.56 kcal/mol which was found to be a better binder when compared to previously reported JNK inducer (PC‐12). Overall, we herein report the analytically pure IA‐7 as lead structure that could be used as a template to develop target based anticancer agents where JNK modulation is predominant.

Reduced SH3RF3 may protect against Alzheimer's disease by lowering microglial pro-inflammatory responses via modulation of JNK and NFkB signaling.

Understanding how high-risk individuals are protected from Alzheimer's disease (AD) may illuminate potential therapeutic targets. A previously identified non-coding SNP in SH3RF3/POSH2 significantly delayed disease onset in a Caribbean Hispanic cohort carrying the PSEN1 G206A mutation sufficient to cause early-onset AD and microglial expression of SH3RF3 has been reported to be a key driver of late-onset AD. SH3RF3 acts as a JNK pathway scaffold and can activate NFκB signaling. While effects of SH3RF3 knockdown in human neurons were subtle, including decreased phospho-tau S422, knockdown in human microglia significantly reduced inflammatory cytokines in response to either a viral mimic or oligomeric Aβ42. This was associated with reduced activation of JNK and NFκB pathways in response to these stimuli. Pharmacological inhibition of JNK or NFκB signaling phenocopied SH3RF3 knockdown. We also found PSEN1 G206A microglia have reduced inflammatory responses to oAβ42. Thus, further reduction of microglial inflammatory responses in PSEN1 mutant carriers by protective SNPs in SH3RF3 might reduce the link between amyloid and neuroinflammation to subsequently delay the onset of AD.

Atorvastatin protects against cyclophosphamide-induced thyroid injury in rats via modulation of JNK/ ERK/ p38 MAPK signaling pathway

BackgroundCancer chemotherapy is associated with various tissue toxicities that limit its use. Cyclophosphamide (CYC) is one of the most commonly used antineoplastic and immunosuppressive agent. Thyroid dysfunction is a critical side effect of anticancer drugs. Atorvastatin (ATV) is antihyperlipedemic drug with different tissue protective activities. The aim of this study was to determine the potential protective effect of ATV against CYC-induced thyroid injury in rats. MethodsATV was administered in the presence and absence of CYC. Thirty-two adult Wistar rats were randomly divided into four groups: control group, ATV group (20 mg/kg/day, p.o. for 14 day), CYC group (200 mg/kg, i.p. on day 9) and ATV/CYC group. Triiodothyronine (T3), thyroxine (T4), reduced glutathione (GSH), malondialdehyde (MDA), total nitrite/nitrate (NOx), p38 mitogen-activated protein kinase (P38MAPK), extracellular signal-regulated kinase (ERK) and c-Jun N-terminal Kinase (JNK) were measured. In addition, thyroid histopathology and caspase 3 immunohistochemistry were performed. ResultsCYC significantly increased thyroid MDA, NOx, P38MAPK, ERK and JNK with decrease in GSH, T3 and T4 levels. Histopathological features of thyroid lesions and increased caspase 3 immune expression were appeared. ATV significantly normalized distributed oxidative, inflammatory and apoptotic indicators, resulting in an improvement of histopathological features and reduction of caspase 3 immunoexpression. ConclusionThese findings suggest that ATV protects against CYC-induced thyroid injury by regulating the JNK/ERK/p38-MAPK signaling pathway.

Pharmacological Akt and JNK Kinase Inhibitors 10-DEBC and SP600125 Potentiate Anti-Glioblastoma Effect of Menadione and Ascorbic Acid Combination in Human U251 Glioblastoma Cells.

Glioblastoma multiforme (GBM) is the most lethal primary brain tumor in adults, characterized by a highly invasive nature and therapy resistance. Combination of menadione and ascorbic acid (AA+MD) exerts strong ROS-mediated anti-GBM activity in vitro. The objective of this study was to improve AA+MD anti-GBM potential by modulating the activity of Akt and c-Jun N-terminal kinase (JNK), molecules with an important role in GBM development. The effects of Akt and JNK modulation on AA+MD toxicity in U251 human glioblastoma cells were assessed by cell viability assays, flow cytometry, RNA interference and plasmid overexpression, and immunoblot analysis. The AA+MD induced severe oxidative stress, an early increase in Akt phosphorylation followed by its strong inhibition, persistent JNK activation, and U251 cell death. Small molecule Akt kinase inhibitor 10-DEBC enhanced, while pharmacological and genetic Akt activation decreased, AA+MD-induced toxicity. The U251 cell death potentiation by 10-DEBC correlated with an increase in the combination-induced autophagic flux and was abolished by genetic autophagy silencing. Additionally, pharmacological JNK inhibitor SP600125 augmented combination toxicity toward U251 cells, an effect linked with increased ROS accumulation. These results indicate that small Akt and JNK kinase inhibitors significantly enhance AA+MD anti-GBM effects by autophagy potentiation and amplifying deleterious ROS levels.

Nicotine alleviates MPTP-induced nigrostriatal damage through modulation of JNK and ERK signaling pathways in the mice model of Parkinson's disease.

Introduction: Nicotine (Nic) has previously been proven to reduce neurodegeneration in the models of Parkinson's disease (PD). The present study is intended to investigate the detailed mechanisms related to the potential neuroprotective effects of Nic in vivo. Methods: We established a PD model using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced C57BL6 mice (25mg/kg/d, 5 d, i.p.) to investigate the neuropharmacological modulation of Nic pretreatment (2.5mg/kg/d, 5 d, i.p., 30min before MPTP injection) from the perspectives of neurobehavioral assessment, the pathological alterations, microglial cell inflammation and MAPK signaling pathways in specific brain regions. Results: The open field test, elevated plus maze, rotarod and traction test suggested that Nic pretreatment could significantly improve MPTP-induced motor impairment and had an anxiolytic effect. Nic was found to improve neuroapoptosis, enhance tyrosine hydroxylase activity, and reduce the accumulation of the phosphorylated α-synuclein in the substantia nigra and striatal regions of PD mice by TUNEL and immunohistochemical assays. Immuno-fluorescent method for labeling Iba1 and CD68 indicated that Nic remarkably alleviates the activation of microglia which represents the M1 polarization state in the mice brain under MPTP stimulation. No significant difference in the expression of p38/MAPK pathway was found in the nigrostriatal regions, while Nic could significantly inhibit the elevated p-JNK/JNK ratio and increase the declined p-ERK/ERK ratio in the substantia nigra of MPTP-exposed brains, which was further confirmed by the pretreatment of CYP2A5 inhibitor to decline the metabolic activity of Nic. Discussion: The molecular signaling mechanism by which Nic exerts its neuroprotective effects against PD may be achieved by regulating the JNK and ERK signaling pathways in the nigra-striatum related brain regions.

Harmine Inhibits Multiple TLR-Induced Inflammatory Expression through Modulation of NF-κB p65, JNK, and STAT1.

Harmine is a beta-carboline alkaloid present in various plants, including in the seeds of Peganum harmala L. This study aimed to investigate the anti-inflammatory activity and mechanism of harmine using macrophages stimulated with various toll-like receptor (TLR) agonists and a model of endotoxemia. The expression of inflammatory mediators induced by ligands of TLRs 2, 3, 4, and 9 were examined in thioglycollate-elicited peritoneal macrophages isolated from BALB/c and C57BL/6 mouse strains. Further, the activation of NF-κB, MAPK, AP-1, and STAT1 was explored using lipopolysaccharide (LPS) and polyinosinic:polycytidylic acid (poly(I:C)). Finally, the liver inflammatory response during endotoxemia was examined. Harmine inhibited inducible nitric oxide synthase, cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-12, and other markers induced by various TLR agonists. The inhibition of NF-κB activity by harmine occurred via the modulation of p65 phosphorylation, independent of IκBα degradation. The inhibition of AP-1 activity by harmine was associated with the modulation of JNK. Harmine inhibited the LPS-induced serine and tyrosine phosphorylation of STAT1, but only affected serine phosphorylation by poly(I:C) treatment. In vivo, harmine inhibited iNOS and COX-2 expression during endotoxemia. Collectively, the results show that harmine can be effective against infectious inflammation through modulation of NF-κB, JNK, and STAT1.

Activation of Laminin γ2 by Helicobacter pylori Promotes Invasion and Survival of Gastric Cancer Cells With E-Cadherin Defects.

Helicobacter pylori infection induces cellular phenotypes relevant for cancer progression, namely cell motility and invasion. We hypothesized that the extracellular matrix (ECM) could be involved in these deleterious effects. Microarrays were used to uncover ECM interactors in cells infected with H. pylori. LAMC2, encoding laminin γ2, was selected as a candidate gene and its expression was assessed in vitro and in vivo. The role of LAMC2 was investigated by small interference RNA (siRNA) combined with a set of functional assays. Laminin γ2 and E-cadherin expression patterns were evaluated in gastric cancer cases. Laminin γ2 was found significantly overexpressed in gastric cancer cells infected with H. pylori. This finding was validated in vitro by infection with clinical isolates and in vivo by using gastric biopsies of infected and noninfected individuals. We showed that laminin γ2 overexpression is dependent on the bacterial type IV secretion system and on the CagA. Functionally, laminin γ2 promotes cell invasion and resistance to apoptosis, through modulation of Src, JNK, and AKT activity. These effects were abrogated in cells with functional E-cadherin. These data highlight laminin γ2 and its downstream effectors as potential therapeutic targets, and the value of H. pylori eradication to delay gastric cancer onset and progression.

Phosphorylation of JIP4 at S730 Presents Antiviral Properties against Influenza A Virus Infection.

Influenza A virus (IAV) is the causative agent of flu disease that results in annual epidemics and occasional pandemics. IAV alters several signaling pathways of the cellular host response in order to promote its replication. Therefore, some of these pathways can serve as targets for novel antiviral agents. Here, we show that c-Jun NH2-terminal kinase (JNK)-interacting protein 4 (JIP4) is dynamically phosphorylated in IAV infection. The lack of JIP4 resulted in higher virus titers, with significant differences in viral protein and mRNA accumulation as early as within the first replication cycle. In accordance, decreased IAV titers and protein accumulation were observed during the overexpression of JIP4. Strikingly, the antiviral function of JIP4 does not originate from modulation of JNK or p38 mitogen-activated protein kinase (MAPK) pathways or from altered expression of interferons or interferon-stimulated genes but rather originates from a direct reduction of viral polymerase activity. Furthermore, the interference of JIP4 with IAV replication seems to be linked to the phosphorylation of the serine at position 730 that is sufficient to impede the viral polymerase. Collectively, we provide evidence that JIP4, a host protein modulated in IAV infection, exhibits antiviral properties that are dynamically controlled by its phosphorylation at S730. IMPORTANCE Influenza A virus (IAV) infection is a world health concern, and current treatment options encounter high rates of resistance. Our group investigates host pathways modified in IAV infection as promising new targets. The host protein JIP4 is dynamically phosphorylated in IAV infection. JIP4 absence resulted in higher virus titers and viral protein and mRNA accumulation within the first replication cycle. Accordingly, decreased IAV titers and protein accumulation were observed during JIP4 overexpression. Strikingly, the antiviral function of JIP4 does not originate from modulation of JNK or p38 MAPK pathways or from altered expression of interferons or interferon-stimulated genes but rather originates from a reduction in viral polymerase activity. The interference of JIP4 with IAV replication is linked to the phosphorylation of serine 730. We provide evidence that JIP4, a host protein modulated in IAV infection, exhibits antiviral properties that are dynamically controlled by its phosphorylation at S730.

Development of Novel Proteasome-HDAC6 Hybrid Inhibitors for Resistant ALL Phenotype

Proteasome inhibitors (PIs) are valuable drugs for the treatment of multiple myeloma. Furthermore, PIs showed encouraging activity against other cancer types and are recently being involved in several clinical trials, also in the treatment of relapsed/refractory ALL and MLL 1, 2. However, they are not able to provide cures as monotherapy. Based on preclinical studies, the combination of PIs with histone deacetylase inhibitors (HDACi) are producing promising synergistic cytotoxicity. Aggresomes are used by many malignant cells as an alternative route to degrade proteins that accumulate after proteasome inhibition. However, this mechanism depends on HDAC6 to transport ubiquitinated proteins by microtubules. Thus, inhibition of the proteasome and HDAC6 results in synergistic anticancer activity by induction of apoptosis in cancer cells. The approach “one drug multiple targets” is gaining major consideration in drug discovery and has been termed polypharmacology. Despite the highly significant therapeutic relevance of combination therapies, potential advantages of a targeted therapy based on a single drug that acts through two independent modes of action include (a) a more predictable pharmacokinetic profile, (b) increased patient compliance, and (c) the simultaneous presence of the molecule in tissues where the active principle is needed to work. We therefore aimed at the design, synthesis and biological evaluation of proteasome-HDAC hybrid inhibitors.The first-in-class dual proteasome-HDAC hybrid inhibitor ‘RTS-V’ was designed by hybridizing the pharmacophores of known HDAC6 selective HDACi 3 and the non-covalent proteasome inhibitor compound 16 4. Autodock 4.2 was used to predict the binding mode of RTS-V into the β5/β6 active site of 20S yeast proteasome (PDB ID: 3MG8) and HDAC6 (PDB ID: 5EDU).The hybrid compound RTS-V was found to fit smoothly into the active site of the the β5 sub-unit of the yeast 20S proteasome and HDAC6 according to docking studies. RTS-V revealed submicromolar and preferential inhibition of HDAC6 in HDAC activity assays. The preferential inhibition of HDAC6 was further confirmed by WB analysis in accordance to Ricolinostat (an orally bioavailable HDAC6 inhibitor). Furthermore, we found that RTS-V specifically blocks chymotrypsin-like proteasome activity, in agreement to Bortezomib (BTZ). Next we screened RTS-V against a panel of more than 20 cell lines and determined the average IC50 values. The screen also included imatinib sensitive/resistant cell lines and three relapse primary BCP-ALL patient samples. Besides that, in three leukemic cells lines we could show that RTS-V inhibits cell proliferation, induces apoptosis, accumulates cells in S phase, induces early differentiation and inhibits colony formation. Like BTZ, RTS-V also acts through modulation of BCL-2, AKT, JNK and MAPK signaling pathways. PBMNCs and MSCs derived from five healthy individuals were treated with RTS-V and later determined the average IC50 values, which was found >20-fold higher than in leukemia cells. These results hint that the cytotoxic effect of RTS-V is significantly less pronounced on healthy cells as compared to leukemic cells.In summary, we have developed a first-in-class proteasome-HDAC6 hybrid inhibitor (RTS-V) with activity against leukemic cell lines and primary relapse human BCP-ALL patient samples. Our next aim would be test its efficacy in in vivo studies. Taken together, RTS-V represents a promising starting point for future efforts towards the development of highly effective dual proteasome-HDAC6 inhibitors to overcome drug resistance, especially for the treatment of relapsed/refractory ALL. 1.ClinicalTrials.gov Identifier: NCT02419755, NCT0131281 & NCT010754252.Messinger, Y., Gaynon, P., Sposto, et al . (2012). Blood 120: 285-290.3.Wagner, F. F.; Olson, D. E.; Gale, et. al. J. Med. Chem. 2013, 56 , 1772-1776.4.Blackburn, C.; Gigstad, K, et. al. Biochem. J. 2010, 430 , 461-476. DisclosuresNo relevant conflicts of interest to declare.

Hydrogen Sulfide Ameliorates Lipopolysaccharide-Induced Memory Impairment in Mice by Reducing Apoptosis, Oxidative, and Inflammatory Effects.

Hydrogen sulfide (H2S) is reported to have a neuroprotective activity; however, the role of H2S in neuroinflammation-induced neuronal damage is ambiguous. Here, we aimed to evaluate the underlying mechanisms for the neuroprotective effect of NaHS, a known H2S donor, against lipopolysaccharide (LPS)-induced memory impairment (MI). All the treatments were administered for 28days, and LPS (0.25mg/kg i.p.) was co-administered intermittently for 7days from days 15 to 21. Morris water maze (MWM) and Y-maze tests were performed to evaluate MI. Neurodegeneration was histopathologically examined, and the brain homogenates were characterized for reduced glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), tumor necrosis factor (TNF)-α, interleukin (IL)-6, caspase-3, c-Jun, and acetylcholinesterase (AChE) by biochemical analysis. H2S administration significantly improved spatial and working memory in MWM and Y-maze tasks, respectively. Exogenous H2S significantly reversed LPS-induced oxidative stress as evidenced by improved GSH, MDA, and SOD levels. H2S pretreatment significantly attenuated LPS-induced apoptosis and inflammation by decreasing c-Jun and caspase-3 levels and inhibiting TNF-α and IL-6, respectively. The decrease in these markers was supported by H&E and Nissl staining, which confirmed the anti-necrotic activity of H2S. However, there was no significant improvement in LPS-induced increase in AChE activity. These results indicate that chronic systemic inflammation leads to neurodegeneration and MI and H2S exerts its neuroprotective effect due to its anti-oxidative, anti-inflammatory, and anti-apoptotic potential via modulation of JNK and extrinsic apoptosis pathways.

JNK in Tumor Microenvironment: Present Findings and Challenges in Clinical Translation

Simple SummaryStress-activated c-Jun N-terminal kinases (JNKs) are members of mitogen-activated protein kinases (MAPKs). Apart from having both tumor promoting and tumor suppressing roles in cancers due to its impact on apoptosis and autophagy pathways, JNK also plays complex roles in the heterogeneous tumor microenvironment (TME) and is involved in different tumorigenesis pathways. The JNK pathway influences various stressful and chronic inflammatory conditions along with different cell populations in TME. In this review, we aim to present the current knowledge of JNK-mediated processes in TME and the challenges in clinical translation.The c-Jun N-terminal kinases (JNKs) are a group of mitogen-activated protein kinases (MAPKs). JNK is mainly activated under stressful conditions or by inflammatory cytokines and has multiple downstream targets for mediating cell proliferation, differentiation, survival, apoptosis, and immune responses. JNK has been demonstrated to have both tumor promoting and tumor suppressing roles in different cancers depending on the focused pathway in each study. JNK also plays complex roles in the heterogeneous tumor microenvironment (TME). JNK is involved in different tumorigenesis pathways. TME closely relates with tumor development and consists of various stressful and chronic inflammatory conditions along with different cell populations, in which the JNK pathway may have various mediating roles. In this review, we aim to summarize the present knowledge of JNK-mediated processes in TME, including hypoxia, reactive oxygen species, inflammation, immune responses, angiogenesis, as well as the regulation of various cell populations within TME. This review also suggests future research directions for translating JNK modulation in pre-clinical findings to clinical benefits.

Naringenin and Vanillin Mitigate Cadmium-Induced Pancreatic Injury in Rats via Inhibition of JNK and p38 MAPK Pathways

Background: Cadmium can induce pancreatic injury via oxidative stress, inflammation and apoptosis. Naringenin (NGN) and vanillin (VLN) exert antioxidant, anti-inflammatory, and antiapoptotic effects. Objective: The likely ameliorative effects of NGN, VLN and their combination were studied in rats exposed to cadmium-induced pancreatic injury. Materials and Methods: Rats received NGN (50 mg/kg/day, p.o.), VLN (100 mg/ kg/day, p.o.), or NGN + VLN for 7 days and one injection of CdCl2 (2 mg/kg, i.p.) on the 6th day. Results: Cadmium significantly lowered serum amylase and insulin levels. Cadmium also caused significant increments of malondialdehyde, tumor necrosis factor-α, interleukin-1β, nuclear factor-κB p65, Bax/Bcl-2 ratio and phosphorylated c-Jun N-terminal kinase (p-JNK) and p38 mitogen-activated protein kinases (MAPKs) and significant decrements of reduced glutathione and catalase in the pancreas of rats received CdCl2. Additionally, CdCl2 caused marked histopathological necrosis and significantly increased caspase-3 expression in pancreatic tissue. The cadmium-induced biochemical, histopathological and immunohistochemical changes were significantly ameliorated by NGN, VLN and NGN + VLN. However, NGN + VLN caused more significant ameliorative effects than did NGN and VLN alone. Conclusion: NGN, VLN and NGN + VLN afforded significant protection of pancreas in rats exposed to cadmium insult through modulation of JNK and p38 MAPK pathways and inhibition of oxidative stress, inflammation and apoptosis.

51-OR: Loss of Critical ER Chaperone GRP78 Leads to Beta-Cell Death by a JNK Dependent Mechanism

Endoplasmic reticulum (ER) health is an important determinant of pancreatic beta cell function or failure. Adaptive ER stress leads to expansion of beta cell number through proliferation, but decompensated ER stress results in beta cell loss and contributes to both T1D and T2D. Therefore, understanding the mechanisms of ER-stress-induced beta cell death could help identify novel strategies for the prevention or treatment of diabetes. Glucose responsive protein GRP78/HSPA5 is a key ER chaperone. Loss of GRP78 causes cell death in many cell types; including, in our own prior work, the beta cell. To study the mechanism by which GRP78 loss leads to beta cell death we devised an ex vivo model of GRP78 knockdown by transducing Grp78-flox mouse islets with adenovirus expressing Cre recombinase. To study human islets, we used adenovirus expressing shRNA against GRP78. Using these tools, we successfully reduced GRP78 RNA and protein in primary mouse and human islet cells. Loss of GRP78 strongly activated the ATF6, IRE1 and PERK pathways of the unfolded protein response (UPR). GRP78 knockdown decreased beta cell number due to increased cell death as measured by Annexin V and TUNEL staining. Probing the mechanisms of cell loss, we found that loss of GRP78 activated multiple death-related pathways, notably autophagy and apoptosis; cell death effectors Chop, caspase 9 and cleaved caspase 3 were increased. Additionally, GRP78 deletion increased stress kinase JNK (c-Jun-N-terminal kinase) which has been implicated in cellular proliferation as well as cell death. Inhibition of JNK kinase using JNK-IN-8 inhibitor during GRP78 loss conditions decreased phosphorylation of JNK and rescued beta cells from cell death as measured with Annexin V and TUNEL. Therefore, we conclude that ER stress related cell death induced by loss of GRP78 (ER stress) involves JNK activation, and that modulation of JNK under certain circumstances may help maintain beta cell mass to protect against diabetes. Disclosure R.B. Sharma: None. C.O. Darko: None. B. Gablaski: None. A.S. Lee: None. L.C. Alonso: Consultant; Self; Fairbanks Pharmaceuticals Inc. Research Support; Self; American Diabetes Association. Funding National Institute of Diabetes and Digestive and Kidney Diseases (5R01DK113300-02)

Ginkgo biloba Extract Protects against Methotrexate-Induced Hepatotoxicity: A Computational and Pharmacological Approach.

Ginkgo biloba extract possess several promising biological activities; currently, it is clinically employed in the management of several diseases. This research work aimed to extrapolate the antioxidant and anti-inflammatory effects of Ginkgo biloba (Gb) in methotrexate (MTX)-induced liver toxicity model. These effects were analyzed using different in vivo experimental approaches and by bioinformatics analysis. Male SD rats were grouped as follows: saline; MTX; Gb (pretreated for seven days with 60, 120, and 180 mg/kg daily dose before MTX treatment); silymarin (followed by MTX treatment); Gb 180 mg/kg daily only; and silymarin only. Histopathological results revealed that MTX induced marked hepatic injury, associated with a substantial surge in various hepatic enzymes such as alanine transaminase (ALT), aspartate transaminase (AST), and serum alkaline phosphatase (ALP). Furthermore, MTX caused the triggering of oxidative distress associated with a depressed antioxidant system. All these injury markers contributed to a significant release of apoptotic (caspase-3 and c-Jun N-terminal kinases (JNK)) and tumor necrosis factor (TNF-α)-like inflammatory mediators. Treatment with Gb counteracts MTX-mediated apoptosis and inflammation dose-dependently along with modulating the innate antioxidative mechanisms such as glutathione (GSH) and glutathione S-transferase (GST). These results were further supplemented by in silico study to analyze drug-receptor interactions (for several Gb constituents and target proteins) stabilized by a low energy value and with a good number of hydrogen bonds. These findings demonstrated that Gb could ameliorate MTX-induced elevated liver reactive oxygen species (ROS) and inflammation, possibly by JNK and TNF-α modulation.

COVID-19 transmission through host cell directed network of GPCR.

COVID-19 transmission through host cell directed network of GPCR.

Hepatoprotective effects of melatonin and celecoxib against ethanol-induced hepatotoxicity in rats

Objectives: Several studies demonstrated the antioxidant and anti-inflammatory role of melatonin and celecoxib. This study is designed to explore the underlying mechanism of hepatoprotective effects of melatonin and celecoxib against ethanol-induced hepatotoxicity by morphological, and biochemical approaches.Materials and methods: Adult male rats were divided into five groups: saline, ethanol, melatonin, and celecoxib were administered for 11 consecutive days after ethanol injection. Biochemical analyses were performed for the determination of glutathione (GSH), glutathione S-transferase (GST), and inducible nitric oxide (iNOS). Immunohistochemistry was performed to determine the level of different inflammatory markers.Results: Histopathological results showed that ethanol-induced marked hepatic injury leads to cloudy swelling, hydropic degeneration, apoptosis, and focal necrosis in all hepatic zones. Biochemical analysis revealed significant increases in serum transaminases and alkaline phosphatase in the ethanol group. Oxidative stress associated with attenuated antioxidant enzymes was also spotted in the ethanol group, as ethanol down-regulated GSH, GST, and upregulated NO. Additionally, ethanol increased the activation and the expression of tumor necrotic factor (TNF-α), p-NFKB, and COX2. Finally, hepatic cellular apoptosis was clearly obvious in ethanol intoxicated animals using activated JNK staining.Conclusion: These results provided pieces of evidence that the hepatoprotective effect of melatonin and celecoxib is possibly mediated through the modulation of JNK and TNF-α signaling pathways with subsequent suppression of inflammatory and apoptotic processes.

CZYH Alleviates β-Amyloid-Induced Cognitive Impairment and Inflammation Response via Modulation of JNK and NF-κB Pathway in Rats.

Cu-Zhi-Yi-Hao (CZYH), an empirical formula of traditional Chinese medicine (TCM), has been used for amnesia treatment in clinical practice. However, its underlying pharmacological mechanism has not been fully illuminated. The current study was designed to investigate the neuroprotective effect of CZYH on a β-amyloid 25-35- (Aβ25-35-) induced learning and memory deficit rat model. CZYH (200, 400, or 800 mg/kg), donepezil (1.0 mg/kg), or distilled water was given to Aβ25-35-stimulated animals for 17 days consecutively. The Morris water maze test revealed that CZYH (400 or 800 mg/kg) administration improved the Aβ25-35-induced cognitive impairments in rats, and Nissl staining demonstrated that CZYH mitigated the Aβ-caused neuron loss. In addition, CZYH treatment markedly inhibited the activation of microglia as evidenced by a decreased level of IBA-1 and increased YM-1/2 protein expression. The protein expression levels of TNF-α, IL-1β, and COX-2 were also repressed by CZYH. Besides, CZYH treatment alleviated Aβ-induced IκB-α degradation and NF-κB p65 phosphorylation, as well as reduced the JNK phosphorylation level. In conclusion, the present study suggests that CZYH could improve learning and memory abilities and relieve neuron loss in Aβ25-35-induced rats, at least partly through inhibition of the neuroinflammatory response via inhibiting the JNK-dependent NF-κB activation, indicating that CZYH might be a promising formula for the treatment of AD.

Escitalopram Ameliorates Cognitive Impairment in D-Galactose-Injected Ovariectomized Rats: Modulation of JNK, GSK-3\u03b2, and ERK Signalling Pathways

Though selective serotonin reuptake inhibitors (SSRIs) have been found to increase cognitive performance in some studies on patients and animal models of Alzheimer’s disease (AD), other studies have reported contradictory results, and the mechanism of action has not been fully described. This study aimed to examine the effect of escitalopram, an SSRI, in an experimental model of AD and to determine the involved intracellular signalling pathways. Ovariectomized rats were administered D-galactose (150 mg/kg/day, i.p) over ten weeks to induce AD. Treatment with escitalopram (10 mg/kg/day, p.o) for four weeks, starting from the 7th week of D-galactose injection, enhanced memory performance and attenuated associated histopathological changes. Escitalopram reduced hippocampal amyloid β 42, β-secretase, and p-tau, while increasing α-secretase levels. Furthermore, it decreased tumor necrosis factor-α, nuclear factor-kappa B p65, and NADPH oxidase, while enhancing brain-derived neurotrophic factor, phospho-cAMP response element binding protein, and synaptophysin levels. Moreover, escitalopram diminished the protein expression of the phosphorylated forms of c-Jun N-terminal kinase (JNK)/c-Jun, while increasing those of phosphoinositide 3-kinase (PI3K), protein kinase B (Akt), glycogen synthase kinase-3β (GSK-3β), extracellular signal-regulated kinase (ERK) and its upstream kinases MEK and Raf-1. In conclusion, escitalopram ameliorated D-galactose/ovariectomy-induced AD-like features through modulation of PI3K/Akt/GSK-3β, Raf-1/MEK/ERK, and JNK/c-Jun pathways.