The transcriptional activity of NF-kappaB is regulated by the IkappaB-associated PKAc subunit through a cyclic AMP-independent mechanism

Post-translational modifications of p65: state of the art

P65, a protein subunit of NF-κB, is a widely distributed transcription factor in eukaryotic cells and exerts diverse regulatory functions. Post-translational modifications such as phosphorylation, acetylation, methylation and ubiquitination modulate p65 transcriptional activity and function, impacting various physiological and pathological processes including inflammation, immune response, cell death, proliferation, differentiation and tumorigenesis. The intricate interplay between these modifications can be antagonistic or synergistic. Understanding p65 post-translational modifications not only elucidates NF-κB pathway regulation but also facilitates the identification of therapeutic targets and diagnostic markers for associated clinical conditions.

NFκB signalling in colorectal cancer: Examining the central dogma of IKKα and IKKβ signalling

The NFκB pathway, known as the central regulator of inflammation, has a well-established role in colorectal cancer (CRC) initiation, progression, and therapy resistance. Due to the pathway's overarching roles in CRC, there have been efforts to characterise NFκB family members and target the pathway for therapeutic intervention. Initial research illustrated that the canonical NFκB pathway, driven by central kinase IKKβ, was a promising target for drug intervention. However, dose limiting toxicities and specificity concerns have resulted in failure of IKKβ inhibitors in clinical trials. The field has turned to look at targeting the less dominant kinase, IKKα, which along with NFκB inducing kinase (NIK), drives the lesser researched non-canonical NFκB pathway. However prognostic studies of the non-canonical pathway have produced conflicting results. There is emerging evidence that IKKα is involved in other signalling pathways, which lie outside of canonical and non-canonical NFκB signalling. Evidence suggests that some of these alternative pathways involve a truncated form of IKKα, and this may drive poor cancer-specific survival in CRC. This review aims to explore the multiple components of NFκB signalling, highlighting that NIK may be the central kinase for non-canonical NFκB signalling, and that IKKα is involved in novel pathways which promote CRC.

The Prolonged Activation of the p65 Subunit of the NF-Kappa-B Nuclear Factor Sustains the Persistent Effect of Advanced Glycation End Products on Inflammatory Sensitization in Macrophages

Advanced glycation end products (AGEs) prime macrophages for lipopolysaccharide (LPS)-induced inflammation. We investigated the persistence of cellular AGE-sensitization to LPS, considering the nuclear content of p50 and p65 nuclear factor kappa B (NFKB) subunits and the expression of inflammatory genes. Macrophages treated with control (C) or AGE-albumin were rested for varying intervals in medium alone before being incubated with LPS. Comparisons were made using one-way ANOVA or Student t-test (n = 6). AGE-albumin primed macrophages for increased responsiveness to LPS, resulting in elevated levels of TNF, IL-6, and IL-1beta (1.5%, 9.4%, and 5.6%, respectively), compared to C-albumin. TNF, IL-6, and IL-1 beta secretion persisted for up to 24 h even after the removal of AGE-albumin (area under the curve greater by 1.6, 16, and 5.2 times, respectively). The expressions of Il6 and RelA were higher 8 h after albumin removal, and Il6 and Abca1 were higher 24 h after albumin removal. The nuclear content of p50 remained similar, but p65 showed a sustained increase (2.9 times) for up to 24 h in AGE-albumin-treated cells. The prolonged activation of the p65 subunit of NFKB contributes to the persistent effect of AGEs on macrophage inflammatory priming, which could be targeted for therapies to prevent complications based on the AGE-RAGE-NFKB axis.

Glucose inhibits the inflammatory response in goose fatty liver by increasing the ubiquitination level of PKA

Protein kinase A (PKA) plays an important role in cellular life activities. Recently, PKA was found to bind to the inhibitor of nuclear factor-kappaB (IκB), a key protein in the nuclear factor-kappaB (NF-κB) pathway, to form a complex involved in the regulation of inflammatory response. However, the role of PKA in the anti-inflammatory of goose fatty liver is still unclear. A total of 14 healthy 70-d-old male Lander geese were randomly divided into a control group and an overfeeding group. Inflammation level was analyzed by histopathological method in the liver. The mRNA and protein abundance of PKA and tumor necrosis factor-alpha (TNFα), as well as the ubiquitination level of PKA, were detected. Moreover, goose primary hepatocytes were cotreated with glucose, harringtonine, and carbobenzoxy-l-leucyl-l-leucyl-l-leucinal (MG132). Finally, the co-immunoprecipitated samples of PKA from the control and overfeeding group were used for protein mass spectrometry. The results showed that no difference in PKA mRNA expression was observed (P > 0.05), while the PKA protein level in the overfed group was significantly reduced (P < 0.05) when compared with the control group. The ubiquitination level of PKA was higher than that of the control group in fatty liver. The mRNA expression of PKA was elevated but protein abundance was reduced in goose primary hepatocytes with 200 mmol/L glucose treatment (P < 0.05). The PKA protein abundance was dramatically reduced in hepatocytes treated with harringtonine (P < 0.01) when compared with the glucose-supplemented group. Nevertheless, MG132 tended to alleviate the inhibitory effect of harringtonine on PKA protein abundance (P = 0.081). There was no significant difference in TNFα protein level among glucose-treated groups and control (P > 0.05). Protein mass spectrometry analysis showed that 29 and 76 interacting proteins of PKA were screened in goose normal and fatty liver, respectively. Validation showed that PKA interacted with the E3 ubiquitination ligases ring finger protein 135 (RNF135) and potassium channel modulatory factor 1 (KCMF1). In summary, glucose may inhibit the inflammatory response in goose fatty liver by increasing the ubiquitination level of PKA. Additionally, RNF135 and KCMF1 may be involved in the regulation of PKA ubiquitination level as E3 ubiquitination ligases.

8-Oxoguanine DNA glycosylase 1 selectively modulates ROS-responsive NF-κB targets through recruitment of MSK1 and phosphorylation of RelA/p65 at Ser276

Nuclear factor kappa B (NF-κB) activity is regulated by various posttranslational modifications, of which Ser276 phosphorylation of RelA/p65 is particularly impacted by reactive oxygen species (ROS). This modification is responsible for selective upregulation of a subset of NF-κB targets; however, the precise mechanism remains elusive. ROS have the ability to modify cellular molecules including DNA. One of the most common oxidation products is 8-oxo-7,8-dihydroguanine (8-oxoGua), which is repaired by the 8-oxoguanine DNA glycosylase1 (OGG1)-initiated base excision repair pathway. Recently, a new function of OGG1 has been uncovered. OGG1 binds to 8-oxoGua, facilitating the occupancy of NF-κB at promoters and enhancing transcription of pro-inflammatory cytokines and chemokines. In the present study, we demonstrated that an interaction between DNA-bound OGG1 and mitogen-and stress-activated kinase 1 is crucial for RelA/p65 Ser276 phosphorylation. ROS scavenging or OGG1 depletion/inhibition hindered the interaction between mitogen-and stress-activated kinase 1 and RelA/p65, thereby decreasing the level of phospho-Ser276 and leading to significantly lowered expression of ROS-responsive cytokine/chemokine genes, but not that of Nfkbis. Blockade of OGG1 binding to DNA also prevented promoter recruitment of RelA/p65, Pol II, and p-RNAP II in a gene-specific manner. Collectively, the data presented offer new insights into how ROS signaling dictates NF-κB phosphorylation codes and how the promoter-situated substrate-bound OGG1 is exploited by aerobic mammalian cells for timely transcriptional activation of ROS-responsive genes.

NFκB and Cyclic AMP Response Element Sites Mediate the Valproic Acid and UL138 Responsiveness of the Human Cytomegalovirus Major Immediate Early Enhancer and Promoter

The major immediate early enhancer and promoter (MIEP) of human cytomegalovirus (HCMV) drives the transcription of the immediate early one (IE1) and IE2 genes, whose encoded proteins stimulate productive, lytic replication. The MIEP is activated by the virally encoded and tegument-delivered pp71 protein at the start of de novo lytic infections of fully differentiated cells. Conversely, the MIEP is silenced at the start of de novo latent infections within incompletely differentiated myeloid cells in part because tegument-delivered pp71 is sequestered in the cytoplasm in these cells, but also by viral factors that repress transcription from this locus, including the UL138 protein. During both modes of infection, MIEP activity can be increased by the histone deacetylase inhibitor valproic acid (VPA); however, UL138 inhibits the VPA-responsiveness of the MIEP. Here, we show that two families of cellular transcription factors, NF-κB and cAMP response element-binding protein (CREB), together control the VPA-mediated activation and UL138-mediated repression of the HCMV MIEP. IMPORTANCE Artificial regulation of the HCMV MIEP, either activation or repression, is an attractive potential means to target the latent reservoirs of virus for which there is currently no available intervention. The MIEP could be repressed to prevent latency reactivation or induced to drive the virus into the lytic stage that is visible to the immune system and inhibited by multiple small-molecule antiviral drugs. Understanding how the MIEP is regulated is a critical part of designing and implementing either strategy. Our revelation here that NF-κB and CREB control the responsiveness of the MIEP to the viral UL138 protein and the FDA-approved drug VPA could help in the formulation and execution of promoter regulatory strategies against latent HCMV.

Ethylhexadecyldimethylammonium bromide, a quaternary ammonium compound, controls inflammatory response through NRF2 pathway in a human immortalized keratinocyte cell line

Many everyday products contain quaternary ammonium compounds (QAC) and some of them are known to be skin irritants such as benzalkonium chloride. Others, such as didecyldimethylammonium chloride, have been shown to cause allergic contact dermatitis. Ethylhexadecyldimethylammonium bromide (EHD) is a QAC for which sensitization potential is not clearly known. Therefore, we have studied its mechanism in human keratinocytes (KC), the main cells of the epidermis. We used the well-described human KC cell line KERTr exposed to EHD, cinnamaldehyde (CinA), a well-known skin sensitizer, and a mixture of both. Since chemical sensitizers are known to activate the transcription factor nuclear factor (erythroid-derived 2)-like 2 (NRF2), leading to cellular detoxification and suppressed proinflammatory cytokines, protein or mRNA expression of NRF2 pathway-related enzymes and pro-inflammatory cytokines were investigated by Western blot and RT-qPCR. The activity of the NRF2 pathway on inflammation was studied by RT-qPCR in NRF2-invalidated KERTr cells. We showed that EHD cannot induce the NRF2 pathway, unlike contact sensitizers like CinA. EHD triggers an inflammatory response by inducing the mRNA expression of pro-inflammatory cytokines such as IL-1β or IL-6. Moreover, mixing EHD and CinA inhibits the effect of CinA on NRF2 expression and mitigates the inflammatory response induced by EHD alone. EHD treatment of KERTr cells in which NRF2 has been invalidated showed an exacerbation of the inflammatory response at the transcriptional level. Hence, EHD may elicit an inflammatory response in KC via the NF-κB pathway, which could lead to irritation when applied to the skin. This inflammation is negatively controlled by the basal activity of the NRF2 pathway.

Photooxidation of A2E by Blue Light Regulates Heme Oxygenase 1 Expression via NF-κB and Lysine Methyltransferase 2A in ARPE-19 Cells

Background: N-retinylidene-N-retinylethanolamine (A2E) is a component of drusen that accumulates in retinal cells and induces oxidative stress through photooxidation, such as blue light (BL). We found that the heme oxygenase 1 (HMOX1) gene responds sensitively to photooxidation by the BL of A2E in retinal pigment epithelial (RPE) cells, and we sought to identify the transcription factors and coactivators involved in the upregulation of HMOX1 by A2E and BL. Methods: A2E-laden human RPE cells (ARPE-19) were exposed to BL (430 nm). RNA sequencing was performed to identify genes responsive to BL exposure. Chromatin immunoprecipitation and RT-qPCR were performed to determine the regulation of HMOX1 transcription. Clinical transcriptome data were used to evaluate HMOX1 expression in patients with age-related macular degeneration (AMD). Results: In ARPE-19 cells, the expression of HMOX1, one of the NF-κB target genes, was significantly increased by A2E and BL. The binding of RELA and RNA polymerase II to the promoter region of HMOX1 was significantly increased by A2E and BL. Lysine methyltransferase 2A (MLL1) plays an important role in H3K4me3 methylation, NF-κB recruitment, chromatin remodeling at the HMOX1 promoter, and, subsequently, HMOX1 expression. The retinal tissues of patients with late-stage AMD showed significantly increased expression of HMOX1 compared to normal retinal tissues. In addition, the expression levels of MLL1 and HMOX1 in retinal tissues were correlated. Conclusions: Taken together, our results suggest that BL induces HMOX1 expression by activating NF-κB and MLL1 in RPE cells.

Emerging therapies for autosomal dominant polycystic kidney disease with a focus on cAMP signaling

Autosomal dominant polycystic kidney disease (ADPKD), with an estimated genetic prevalence between 1:400 and 1:1,000 individuals, is the third most common cause of end stage kidney disease after diabetes mellitus and hypertension. Over the last 3 decades there has been great progress in understanding its pathogenesis. This allows the stratification of therapeutic targets into four levels, gene mutation and polycystin disruption, proximal mechanisms directly caused by disruption of polycystin function, downstream regulatory and signaling pathways, and non-specific pathophysiologic processes shared by many other diseases. Dysfunction of the polycystins, encoded by the PKD genes, is closely associated with disruption of calcium and upregulation of cyclic AMP and protein kinase A (PKA) signaling, affecting most downstream regulatory, signaling, and pathophysiologic pathways altered in this disease. Interventions acting on G protein coupled receptors to inhibit of 3',5'-cyclic adenosine monophosphate (cAMP) production have been effective in preclinical trials and have led to the first approved treatment for ADPKD. However, completely blocking cAMP mediated PKA activation is not feasible and PKA activation independently from cAMP can also occur in ADPKD. Therefore, targeting the cAMP/PKA/CREB pathway beyond cAMP production makes sense. Redundancy of mechanisms, numerous positive and negative feedback loops, and possibly counteracting effects may limit the effectiveness of targeting downstream pathways. Nevertheless, interventions targeting important regulatory, signaling and pathophysiologic pathways downstream from cAMP/PKA activation may provide additive or synergistic value and build on a strategy that has already had success. The purpose of this manuscript is to review the role of cAMP and PKA signaling and their multiple downstream pathways as potential targets for emergent therapies for ADPKD.

Ginsenoside Rb1 Reduces D-GalN/LPS-induced Acute Liver Injury by Regulating TLR4/NF-κB Signaling and NLRP3 Inflammasome

BACKGROUND AND AIMS

The effect of ginsenoside Rb1 on D-galactosamine (D-GalN)/lipopolysaccharide (LPS)-induced acute liver injury (ALI) is unknown. The aim of this study was to evaluate the effect of ginsenoside Rb1 on ALI and its underlying mechanisms.

METHODS

Mice were pretreated with ginsenoside Rb1 by intraperitoneal injection for 3 days before D-GalN/LPS treatment, to induce ALI. The survival rate was monitored every hour for 24 h, and serum biochemical parameters, hepatic index and histopathological analysis were evaluated to measure the degree of liver injury. ELISA was used to detect oxidative stress and inflammatory cytokines in hepatic tissue and serum. Immunohistochemistry staining, RT-PCR and western blotting were performed to evaluate the expression of toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB), and NLR family, pyrin domain-containing 3 protein (NLRP3) in liver tissue and Kupffer cells (KCs).

RESULTS

Ginsenoside Rb1 improved survival with D-GalN/LPS-induced ALI by up to 80%, significantly ameliorated the increased alanine and aspartate transaminase, restored the hepatic pathological changes and reduced the levels of oxidative stress and inflammatory cytokines altered by D-GalN/LPS. Compared to the control group, the KCs were increased in the D-GalN/LPS groups but did not increase significantly with Rb1 pretreatment. D-GalN/LPS could upregulate while Rb1 pretreatment could downregulate the expression of interleukin (IL)-1β, IL-18, NLRP3, apoptosis associated speck-like protein containing CARD (ASC) and caspase-1 in isolated KCs. Furthermore, ginsenoside Rb1 inhibited activation of the TLR4/NF-κB signaling pathway and NLRP3 inflammasome induced by D-GalN/LPS administration.

CONCLUSIONS

Ginsenoside Rb1 protects mice against D-GalN/LPS-induced ALI by attenuating oxidative stress and the inflammatory response through the TLR4/NF-κB signaling pathway and NLRP3 inflammasome activation.

High-Intensity Red Light-Emitting Diode Irradiation Suppresses the Inflammatory Response of Human Periodontal Ligament Stem Cells by Promoting Intracellular ATP Synthesis

Periodontitis is an inflammatory lesion in the periodontal tissue. The behavior of human periodontal ligament stem cells (hPDLSCs), which play an important role in periodontal tissue regeneration, is restricted by the influence of inflammatory mediators. Photobiomodulation therapy exerts anti-inflammatory effects. The purpose of this study was to investigate the effects of light-emitting diode (LED) irradiation on the inflammatory responses of hPDLSCs. The light source was a red LED (peak wavelength: 650 nm), and the total absolute irradiance was 400 mW/cm². The inflammatory response in hPDLSCs is induced by tumor necrosis factor (TNF)-α. Adenosine triphosphate (ATP) levels and pro-inflammatory cytokine (interleukin [IL]-6 and IL-8) production were measured 24 h after LED irradiation, and the effects of potassium cyanide (KCN) were investigated. LED irradiation at 6 J/cm² significantly increased the ATP levels and reduced TNF-α-induced IL-6 and IL-8 production. Furthermore, the inhibitory effect of LED irradiation on the production of pro-inflammatory cytokines was inhibited by KCN treatment. The results of this study showed that high-intensity red LED irradiation suppressed the TNF-α-stimulated pro-inflammatory cytokine production in hPDLSCs by promoting ATP synthesis. These results suggest that high-intensity red LED is a useful tool for periodontal tissue regeneration in chronically inflamed tissues.

Cyclic-AMP Increases Nuclear Actin Monomer Which Promotes Proteasomal Degradation of RelA/p65 Leading to Anti-Inflammatory Effects

The second messenger, cAMP has potent immunosuppressive and anti-inflammatory actions. These have been attributed, in part, to the ability of cAMP-induced signals to interfere with the function of the proinflammatory transcription factor Nuclear Factor-kappa B (NF-κB). However, the mechanisms underlying the modulation of NF-κB activity by cAMP remain unclear. Here we demonstrate an important role for cAMP-mediated increase in nuclear actin monomer levels in inhibiting NF-κB activity. Elevated cAMP or forced expression of a nuclear localised polymerisation defective actin mutant (NLS-Actin_R62D) inhibited basal and TNFα induced mRNA levels of NF-κB-dependent genes and NF-κB-dependent reporter gene activity. Elevated cAMP or NLS-Actin_R62D did not affect NF-κB nuclear translocation but did reduce total cellular and nuclear RelA/p65 levels. Preventing the cAMP-induced increase in nuclear actin monomer, either by expressing a nuclear localised active mutant of the actin polymerising protein mDIA, silencing components of the nuclear actin import complex IPO9 and CFL1 or overexpressing the nuclear export complex XPO6, rescued RelA/p65 levels and NF-κB reporter gene activity in forskolin-stimulated cells. Elevated cAMP or NLS-Actin_R62D reduced the half-life of RelA/p65, which was reversed by the proteasome inhibitor MG132. Accordingly, forskolin stimulated association of RelA/p65 with ubiquitin affinity beads, indicating increased ubiquitination of RelA/p65 or associated proteins. Taken together, our data demonstrate a novel mechanism underlying the anti-inflammatory effects of cAMP and highlight the important role played by nuclear actin in the regulation of inflammation.

Protein Kinase A Downregulation Delays the Development and Progression of Polycystic Kidney Disease

Background: Upregulation of cAMP-dependent and -independent PKA signaling is thought to promote cystogenesis in polycystic kidney disease (PKD). PKA-I regulatory subunit RIα is increased in kidneys of orthologous mouse models. Kidney-specific knockout of RIα upregulates PKA activity, induces cystic disease in wild-type mice, and aggravates it in Pkd1 ^RC/RC mice. Methods: PKA-I activation or inhibition was compared to EPAC activation or PKA-II inhibition using Pkd1 ^RC/RC metanephric organ cultures. The effect of constitutive PKA (preferentially PKA-I) downregulation in vivo was ascertained by kidney-specific expression of a dominant negative RIαB allele in Pkd1 ^RC/RC mice obtained by crossing Prkar1α ^R1αB/WT, Pkd1 ^RC/RC, and Pkhd1-Cre mice (C57BL/6 background). The effect of pharmacologic PKA inhibition using a novel, selective PRKACA inhibitor (BLU2864) was tested in mIMCD3 3D cultures, metanephric organ cultures, and Pkd1 ^RC/RC mice on a C57BL/6 x 129S6/Sv F1 background. Mice were sacrificed at 16 weeks of age. Results: PKA-I activation promoted and inhibition prevented ex vivo P-Ser133 CREB expression and cystogenesis. EPAC activation or PKA-II inhibition had no or only minor effects. BLU2864 inhibited in vitro mIMCD3 cystogenesis and ex vivo P-Ser133 CREB expression and cystogenesis. Genetic downregulation of PKA activity and BLU2864 directly and/or indirectly inhibited many pro-proliferative pathways and were both protective in vivo BLU2864 had no detectable on- or off-target adverse effects. Conclusions: PKA-I is the main PKA isozyme promoting cystogenesis. Direct PKA inhibition may be an effective strategy to treat PKD and other conditions where PKA signaling is upregulated. By acting directly on PKA, the inhibition may be more effective than or substantially increase the efficacy of treatments that only affect PKA activity by lowering cAMP.

PKACα negatively regulates TAK1/IRF7 signaling in black carp Mylopharyngodon piceus

Protein Kinase A catalytic subunit α (PKACα), plays an important role in the PKA and NF-κB signaling pathway in mammals. However, the function of PKACα in teleost fish remains largely unknown. In this study, PKACα from black carp (bcPKACα) has been cloned and its role in the innate immune antiviral signaling pathway was investigated. The open reading frame of bcPKACα gene contains 1056 nucleotides and the immunofluorescence assay verified that PKACα was mainly distributed in the cytoplasm. The reporter assay showed that bcPKACα expression and co-expression of bcPKACα and black carp TAK1 (bcTAK1) could activate the transcription of NF-κB. However, bcTAK1/bcIRF7-mediated IFN transcription was inhibited by bcPKACα. Knockdown of bcPKACα showed slightly enhanced antiviral activity against spring viremia of carp virus (SVCV) compared with control group. Accordingly, the antiviral activity against SVCV and grass carp reovirus (GCRV) of EPC cells co-expressing bcPKACα, bcTAK1 and bcIRF7 was obviously lower than that of EPC cells co-expressing bcTAK1 and bcIRF7. The similar subcellular distribution and interaction between bcPKACα and bcTAK1 were detected by immunofluorescent staining and co-immunoprecipitation assay separately. The data generated in this study demonstrates that bcPKACα associates with bcTAK1 and positively regulates NF-κB signaling, however, negatively regulates TAK1/IRF7 signaling pathway.

Phytochemicals: Potential Therapeutic Modulators of Radiation Induced Signaling Pathways

Ionizing radiation results in extensive damage to biological systems. The massive amount of ionizing radiation from nuclear accidents, radiation therapy (RT), space exploration, and the nuclear battlefield leads to damage to biological systems. Radiation injuries, such as inflammation, fibrosis, and atrophy, are characterized by genomic instability, apoptosis, necrosis, and oncogenic transformation, mediated by the activation or inhibition of specific signaling pathways. Exposure of tumors or normal cells to different doses of ionizing radiation could lead to the generation of free radical species, which can release signal mediators and lead to harmful effects. Although previous FDA-approved agents effectively mitigate radiation-associated toxicities, their use is limited due to their high cellular toxicities. Preclinical and clinical findings reveal that phytochemicals derived from plants that exhibit potent antioxidant activities efficiently target several signaling pathways. This review examined the prospective roles played by some phytochemicals in altering signal pathways associated with radiation response.

Activation of the Ae4 (Slc4a9) cation-driven Cl-/HCO3- exchanger by the cAMP-dependent protein kinase in salivary gland acinar cells

Ae4 transporters are critical for Cl- uptake across the basolateral membrane of acinar cells in the submandibular gland (SMG). Although required for fluid secretion, little is known about the physiological regulation of Ae4. To investigate whether Ae4 is regulated by the cAMP-dependent signaling pathway, we measured Cl-/HCO3- exchanger activity in SMG acinar cells from Ae2-/- mice, which only express Ae4, and found that the Ae4-mediated activity was increased in response to β-adrenergic receptor stimulation. Moreover, pretreatment with H89, an inhibitor of the cAMP-activated kinase (PKA), prevented the stimulation of Ae4 exchangers. We then expressed Ae4 in CHO-K1 cells and found that the Ae4-mediated activity was increased when Ae4 is coexpressed with the catalytic subunit of PKA (PKAc), which is constitutively active. Ae4 sequence analysis showed two potential PKA phosphorylation serine residues located at the intracellular NH2-terminal domain according to a homology model of Ae4. NH2-terminal domain Ser residues were mutated to alanine (S173A and S273A, respectively), where the Cl-/HCO3- exchanger activity displayed by the mutant S173A was not activated by PKA. Conversely, S273A mutant kept the PKA dependency. Together, we conclude that Ae4 is stimulated by PKA in SMG acinar cells by a mechanism that probably depends on the phosphorylation of S173.NEW & NOTEWORTHY We found that Ae4 exchanger activity in secretory salivary gland acinar cells is increased upon β-adrenergic receptor stimulation. The activation of Ae4 was prevented by H89, a nonselective PKA inhibitor. Protein sequence analysis revealed two residues (S173 and S273) that are potential targets of cAMP-dependent protein kinase (PKA). Experiments in CHO-K1 cells expressing S173A and S273A mutants showed that S173A, but not S273A, is not activated by PKA.

Depolarization induces nociceptor sensitization by CaV1.2-mediated PKA-II activation

Depolarization drives neuronal plasticity. However, whether depolarization drives sensitization of peripheral nociceptive neurons remains elusive. By high-content screening (HCS) microscopy, we revealed that depolarization of cultured sensory neurons rapidly activates protein kinase A type II (PKA-II) in nociceptors by calcium influx through Ca_V1.2 channels. This effect was modulated by calpains but insensitive to inhibitors of cAMP formation, including opioids. In turn, PKA-II phosphorylated Ser1928 in the distal C terminus of Ca_V1.2, thereby increasing channel gating, whereas dephosphorylation of Ser1928 involved the phosphatase calcineurin. Patch-clamp and behavioral experiments confirmed that depolarization leads to calcium- and PKA-dependent sensitization of calcium currents ex vivo and local peripheral hyperalgesia in the skin in vivo. Our data suggest a local activity-driven feed-forward mechanism that selectively translates strong depolarization into further activity and thereby facilitates hypersensitivity of nociceptor terminals by a mechanism inaccessible to opioids.

The indole-hydantoin derivative exhibits anti-inflammatory activity by preventing the transactivation of NF-κB through the inhibition of NF-κB p65 phosphorylation at Ser276

Indole- and hydantoin-based derivatives both exhibit anti-inflammatory activity, suggesting that the structures of indole and hydantoin are functional for this activity. In the present study, we synthesized two types of indole-hydantoin derivatives, IH-1 (5-(1H-indole-3-ylmethylene) imidazolidine-2,4-dione) and IH-2 (5-(1H-indole-3-ylmethyl) imidazolidine-2,4-dione) and examined their effects on LPS-induced inflammatory responses in murine macrophage-like RAW264.7 cells. LPS-induced inflammatory responses were not affected by indole, hydantoin, or IH-2. In contrast, IH-1 significantly inhibited the LPS-induced production of nitric oxide (NO) and secretion of CCL2 and CXCL1 by suppressing the mRNA expression of inducible NO synthase (iNOS), CCL2, and CXCL1. IH-1 markedly inhibited the LPS-induced activation of NF-κB without affecting the degradation of IκBα or nuclear translocation of NF-κB. IH-1 markedly attenuated the transcriptional activity of NF-κB by suppressing the LPS-induced phosphorylation of the NF-κB p65 subunit at Ser276. Furthermore, IH-1 prevented the LPS-induced interaction of NF-κB p65 subunit with a transcriptional coactivator, cAMP response element-binding protein (CBP). Collectively, these results revealed the potential of the novel indole-hydantoin derivative, IH-1 as an anti-inflammatory drug.

PI3K/ NF-κB-dependent TNF-α and HDAC activities facilitate LPS-induced RGS10 suppression in pulmonary macrophages

Regulator of G-protein signaling 10 (RGS10) is a member of the superfamily of RGS proteins that canonically act as GTPase activating proteins (GAPs). RGS proteins accelerate GTP hydrolysis on the G-protein α subunits and result in termination of signaling pathways downstream of G protein-coupled receptors. Beyond its GAP function, RGS10 has emerged as an anti-inflammatory protein by inhibiting LPS-mediated NF-κB activation and expression of inflammatory cytokines, in particular TNF-α. Although RGS10 is abundantly expressed in resting macrophages, previous studies have shown that RGS10 expression is suppressed in macrophages following Toll-like receptor 4 (TLR4) activation by LPS. However, the molecular mechanism by which LPS induces Rgs10 silencing has not been clearly defined. The goal of the current study was to determine whether LPS silences Rgs10 expression through an NF-κB-mediated proinflammatory mechanism in pulmonary macrophages, a unique type of innate immune cells. We demonstrate that Rgs10 transcript and RGS10 protein levels are suppressed upon LPS treatment in the murine MH-S alveolar macrophage cell line. We show that pharmacological inhibition of PI3K/ NF-κB/p300 (NF-κB co-activator)/TNF-α signaling cascade and the activities of HDAC (1-3) enzymes block LPS-induced silencing of Rgs10 in MH-S cells as well as microglial BV2 cells and BMDMs. Further, loss of RGS10 generated by using CRISPR/Cas9 amplifies NF-κB phosphorylation and inflammatory gene expression following LPS treatment in MH-S cells. Together, our findings strongly provide critical insight into the molecular mechanism underlying RGS10 suppression by LPS in pulmonary macrophages.

Measuring NF-κB Phosphorylation and Acetylation

Posttranslational modifications of NF-κB, including phosphorylation, acetylation, and methylation, have emerged as important regulatory mechanisms to control the transcriptional outcomes of this important transcription factor. These modifications work independently, sequentially or in combination to modulate the diverse biological functions of NF-κB in cancer and inflammatory response. Here, we describe some experimental methods to detect the in vitro and in vivo phosphorylation and acetylation of NF-κB, specifically focusing on the RelA subunit of NF-κB. These methods include labeling the phospho- or acetyl- groups with radioisotopes in vitro and immunoblotting with site-specific anti-phospho-serine or acetyl-lysine antibodies in culture cells and tissue samples.

Herpes Simplex Virus Type 2 Glycoprotein D Inhibits NF-κB Activation by Interacting with p65

NF-κB plays a crucial role in regulating cell proliferation, inflammation, apoptosis, and immune responses. HSV type 2 (HSV-2) is one of the most predominant sexually transmitted pathogens worldwide, and its infection increases the risk of HIV type 1 (HIV-1) acquisition and transmission. HSV-2 glycoprotein D (gD), highly homologous to HSV-1 gD, is essential for viral adhesion, fusion, entry, and spread. It is known that HSV-1 gD can bind herpesvirus entry mediator (HVEM) to trigger NF-κB activation and thereby facilitate viral replication at the early stage of infection. In this study, we found that purified HSV-2 gD triggered NF-κB activation at the early stage of infection, whereas ectopic expression of HSV-2 gD significantly downregulated TNF-α-induced NF-κB activity as well as TNF-α-induced IL-6 and IL-8 expression. Mechanistically, HSV-2 gD inhibited NF-κB, but not IFN-regulatory factor 3 (IRF3), activation and suppressed NF-κB activation mediated by overexpression of TNFR-associated factor 2 (TRAF2), IκB kinase α (IKKα), IKKβ, or p65. Coimmunoprecipitation and binding kinetic analyses demonstrated that HSV-2 gD directly bound to the NF-κB subunit p65 and abolished the nuclear translocation of p65 upon TNF-α stimulation. Mutational analyses further revealed that HSV-2 gD interacted with the region spanning aa 19-187 of p65. Findings in this study together demonstrate that HSV-2 gD interacts with p65 to regulate p65 subcellular localization and thereby prevents NF-κB-dependent gene expression, which may contribute to HSV-2 immune evasion and pathogenesis.

Myosin 1c: A novel regulator of glucose uptake in brown adipocytes

Objective

The potential of brown adipose tissue (BAT) to influence energy homeostasis in animals and humans is encouraging as this tissue can increase fatty acid and glucose utilization to produce heat through uncoupling protein 1 (UCP1), but the actual mechanism of how the cell regulates glucose uptake is not fully understood. Myosin 1c (Myo1c) is an unconventional motor protein involved in several cellular processes, including insulin-mediated glucose uptake via GLUT4 vesicle fusion in white adipocytes, but its role in glucose uptake in BAT has not previously been investigated.

Methods

Using the specific inhibitor pentachloropseudilin (PClP), a neutralizing antibody assay, and siRNA, we examined the role of Myo1c in mechanisms leading to glucose uptake both in vitro in isolated mouse primary adipocytes and in vivo in mice.

Results

Our results show that inhibition of Myo1c removes insulin-stimulated glucose uptake in white adipocytes, while inducing glucose uptake in brown adipocytes, independent of GLUT4, by increasing the expression, translation, and translocation of GLUT1 to the plasma membrane. Inhibition of Myo1c leads to the activation of PKA and downstream substrates p38 and ATF-2, which are known to be involved in the expression of β-adrenergic genes.

Conclusions

Myo1c is a PKA repressor and regulates glucose uptake into BAT.

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Myo1c is a BAT-specific regulator of glucose uptake.

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Myo1c inhibition leads to increased expression, translation, and translocation of GLUT1.

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Myo1c inhibition results in increased activation of PKA and its downstream targets.

Inflammation promotes adipocyte lipolysis via IRE1 kinase

Obesity associates with inflammation, insulin resistance, and higher blood lipids. It is unclear if immune responses facilitate lipid breakdown and release from adipocytes via lipolysis in a separate way from hormones or adrenergic signals. We found that an ancient component of ER stress, inositol-requiring protein 1 (IRE1), discriminates inflammation-induced adipocyte lipolysis versus lipolysis from adrenergic or hormonal stimuli. Our data show that inhibiting IRE1 kinase activity was sufficient to block adipocyte-autonomous lipolysis from multiple inflammatory ligands, including bacterial components, certain cytokines, and thapsigargin-induced ER stress. IRE1-mediated lipolysis was specific for inflammatory triggers since IRE1 kinase activity was dispensable for isoproterenol and cAMP-induced lipolysis in adipocytes and mouse adipose tissue. IRE1 RNase activity was not associated with inflammation-induced adipocyte lipolysis. Inhibiting IRE1 kinase activity blocked NF-κB activation, interleukin-6 secretion, and adipocyte-autonomous lipolysis from inflammatory ligands. Inflammation-induced lipolysis mediated by IRE1 occurred independently from changes in insulin signaling in adipocytes, suggesting that inflammation can promote IRE1-mediated lipolysis independent of adipocyte insulin resistance. We found no role for canonical unfolded protein responses or ABL kinases in linking ER stress to IRE1-mediated lipolysis. Adiponectin-Cre-mediated IRE1 knockout in mice showed that adipocyte IRE1 was required for inflammatory ligand-induced lipolysis in adipose tissue explants and that adipocyte IRE1 was required for approximately half of the increase in blood triglycerides after a bacterial endotoxin-mediated inflammatory stimulus in vivo. Together, our results show that IRE1 propagates an inflammation-specific lipolytic program independent from hormonal or adrenergic regulation. Targeting IRE1 kinase activity may benefit metabolic syndrome and inflammatory lipid disorders.

A most versatile kinase: The catalytic subunit of PKA in T-cell biology

The cAMP-dependent protein kinase, more commonly referred to as protein kinase A (PKA), is one of the most-studied enzymes in biology. PKA is ubiquitously expressed in mammalian cells, can be activated in response to a plethora of biological stimuli, and phosphorylates more than 250 known substrates. Indeed, PKA is of central importance to a wide range of organismal processes, including energy homeostasis, memory formation and immunity. It serves as the primary effector of the second-messenger molecule 3',5'-cyclic adenosine monophosphate (cAMP), which is believed to have mostly inhibitory effects on the adaptive immune response. In particular, elevated levels of intracellular cAMP inhibit the activation of conventional T cells by limiting signal transduction through the T-cell receptor and altering gene expression, primarily in a PKA-dependent manner. Regulatory T cells have been shown to increase the cAMP levels in adjacent T cells by direct and indirect means, but the role of cAMP within regulatory T cells themselves remains incompletely understood. Paradoxically, cAMP has been implicated in promoting T-cell activation as well, adding another functional dimension beyond its established immunosuppressive effects. Furthermore, PKA can phosphorylate the NF-κB subunit p65, a transcription factor that is essential for T-cell activation, independently of cAMP. This phosphorylation of p65 drastically enhances NF-κB-dependent transcription and thus is likely to facilitate immune activation. How these immunosuppressive and immune-activating properties of PKA balance in vivo remains to be elucidated. This review provides a brief overview of PKA regulation, its ability to affect NF-κB activation, and its diverse functions in T-cell biology.

Physiological And Pathological Roles Of Protein Kinase A In The Heart

Protein kinase A (PKA) is a central regulator of cardiac performance and morphology. Myocardial PKA activation is induced by a variety of hormones, neurotransmitters and stress signals, most notably catecholamines secreted by the sympathetic nervous system. Catecholamines bind β-adrenergic receptors to stimulate cAMP-dependent PKA activation in cardiomyocytes. Elevated PKA activity enhances Ca2+ cycling and increases cardiac muscle contractility. Dynamic control of PKA is essential for cardiac homeostasis, as dysregulation of PKA signaling is associated with a broad range of heart diseases. Specifically, abnormal PKA activation or inactivation contributes to the pathogenesis of myocardial ischemia, hypertrophy, heart failure, as well as diabetic, takotsubo, or anthracycline cardiomyopathies. PKA may also determine sex-dependent differences in contractile function and heart disease predisposition. Here, we describe the recent advances regarding the roles of PKA in cardiac physiology and pathology, highlighting previous study limitations and future research directions. Moreover, we discuss the therapeutic strategies and molecular mechanisms associated with cardiac PKA biology. In summary, PKA could serve as a promising drug target for cardioprotection. Depending on disease types and mechanisms, therapeutic intervention may require either inhibition or activation of PKA. Therefore, specific PKA inhibitors or activators may represent valuable drug candidates for the treatment of heart diseases.

Molecular Mechanisms and Genetics of Oxidative Stress in Alzheimer's Disease

Alzheimer’s disease is the most common neurodegenerative disorder that can cause dementia in elderly over 60 years of age. One of the disease hallmarks is oxidative stress which interconnects with other processes such as amyloid-β deposition, tau hyperphosphorylation, and tangle formation. This review discusses current thoughts on molecular mechanisms that may relate oxidative stress to Alzheimer’s disease and identifies genetic factors observed from in vitro, in vivo, and clinical studies that may be associated with Alzheimer’s disease-related oxidative stress.

A marine fungus-derived nitrobenzoyl sesquiterpenoid suppresses receptor activator of NF-κB ligand-induced osteoclastogenesis and inflammatory bone destruction

BACKGROUND AND PURPOSE

Osteoclasts are unique cells to absorb bone. Targeting osteoclast differentiation is a therapeutic strategy for osteolytic diseases. Natural marine products have already become important sources of new drugs. The naturally occurring nitrobenzoyl sesquiterpenoids first identified from marine fungi in 1998 are bioactive compounds with a special structure, but their pharmacological functions are largely unknown. Here, we investigated six marine fungus-derived nitrobenzoyl sesquiterpenoids on osteoclastogenesis and elucidated the mechanisms.

EXPERIMENTAL APPROACH

Compounds were first tested by RANKL-induced NF-κB luciferase activity and osteoclastic TRAP assay, followed by molecular docking to characterize the structure-activity relationship. The effects and mechanisms of the most potent nitrobenzoyl sesquiterpenoid on RANKL-induced osteoclastogenesis and bone resorption were further evaluated in vitro. Micro-CT and histology analysis were used to assess the prevention of bone destruction by nitrobenzoyl sesquiterpenoids in vivo.

KEY RESULTS

Nitrobenzoyl sesquiterpenoid 4, with a nitrobenzoyl moiety at C-14 and a hydroxyl group at C-9, was the most active compound on NF-κB activity and osteoclastogenesis. Consequently, nitrobenzoyl sesquiterpenoid 4 exhibited suppression of RANKL-induced osteoclastogenesis and bone resorption from 0.5 μM. It blocked RANKL-induced IκBa phosphorylation, NF-κB p65 and RelB nuclear translocation, NFATc1 activation, reduced DC-STAMP but not c-Fos expression during osteoclastogenesis in vitro. Nitrobenzoyl sesquiterpenoid 4 also ameliorated LPS-induced osteolysis in vivo.

CONCLUSION AND IMPLICATIONS

These results highlighted nitrobenzoyl sesquiterpenoid 4 as a novel inhibitor of osteoclast differentiation. This marine-derived sesquiterpenoid is a promising lead compound for the treatment of osteolytic diseases.

cAMP regulates 11β-hydroxysteroid dehydrogenase-2 and Sp1 expression in MLO-Y4/MC3T3-E1 cells

11β-hydroxysteroid dehydrogenase-2 (11β-HSD2) is one of the key enzymes in glucocorticoid metabolism, which can inactivate local corticosterone and regulate the level of active glucocorticoid in tissues. The expression of 11β-HSD2 and its regulatory pathway serve an important role in the apoptosis of steroid induced osteonecrosis of the femoral head (SANFH). The present study aimed to identify the regulatory effects of cAMP on the expression of Sp1 transcription factor (Sp1) and 11β-HSD2 in osteocytes at the cellular level. Murine long bone osteocyte Y4 (MLO-Y4) clone cells and mouse embryo osteoblast-like (MC3T3-E1) cells were cultured in vitro with adenylate cyclase activator or inhibitor (forskolin and SQ22536, respectively) to investigate the effects of alterations to intracellular cAMP levels. mRNA and protein expression levels of Sp1 and 11β-HSD2 were detected by reverse transcription-quantitative PCR and western blotting, respectively. Compared with the negative control group, the mRNA and protein expression levels of Sp1 were significantly increased in the activation group, whereas Sp1 expression levels were significantly decreased in the inhibition group. Similarly, compared with the negative control group, the mRNA and protein expression levels of 11β-HSD2 were significantly increased in the activator group, but significantly decreased in the inhibitor group. The aforementioned results indicated that intracellular cAMP levels significantly regulated the expression of Sp1 and 11β-HSD2 in mouse osteocytes and osteoblasts. Therefore, the present study suggested a potential therapeutic strategy for the prevention of osteonecrosis of the femoral head.

Photobiomodulation and Stem Cell Therapy for Temporomandibular Joint Disc Disorders

Background: Temporomandibular disorder (TMD) refers to a group of disorders affecting the temporomandibular joint (TMJ) and its related muscles. The two commonly used treatment modalities for TMD are occlusal splint therapy and relaxation therapy. Neither comprises definitive treatment. Objective: The objective of this review was to report updated information on photobiomodulation and stem cells, as an alternative treatment for the degenerative TMJ disc as a part of TMJ disorders. Materials and methods: With only a few research studies reported till date, this review also proposes the mechanism of laser irradiation on inflammatory mediators to treat TMD. Results: Photobiomodulation of stem cells with and without scaffolds could be used indirectly or directly as modulation of degenerative changes of the TMJ disc. Conclusions: The need for a distinct shift of the research margin in this field of dentistry is evident, specifically regarding the application of photobiomodulation and stem cells for tissue engineering of the TMJ disc.

Modulation of polycystic kidney disease by G-protein coupled receptors and cyclic AMP signaling

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a systemic disorder associated with polycystic liver disease (PLD) and other extrarenal manifestations, the most common monogenic cause of end-stage kidney disease, and a major burden for public health. Many studies have shown that alterations in G-protein and cAMP signaling play a central role in its pathogenesis. As for many other diseases (35% of all approved drugs target G-protein coupled receptors (GPCRs) or proteins functioning upstream or downstream from GPCRs), treatments targeting GPCR have shown effectiveness in slowing the rate of progression of ADPKD. Tolvaptan, a vasopressin V2 receptor antagonist is the first drug approved by regulatory agencies to treat rapidly progressive ADPKD. Long-acting somatostatin analogs have also been effective in slowing the rates of growth of polycystic kidneys and liver. Although no treatment has so far been able to prevent the development or stop the progression of the disease, these encouraging advances point to G-protein and cAMP signaling as a promising avenue of investigation that may lead to more effective and safe treatments. This will require a better understanding of the relevant GPCRs, G-proteins, cAMP effectors, and of the enzymes and A-kinase anchoring proteins controlling the compartmentalization of cAMP signaling. The purpose of this review is to provide an overview of general GPCR signaling; the function of polycystin-1 (PC1) as a putative atypical adhesion GPCR (aGPCR); the roles of PC1, polycystin-2 (PC2) and the PC1-PC2 complex in the regulation of calcium and cAMP signaling; the cross-talk of calcium and cAMP signaling in PKD; and GPCRs, adenylyl cyclases, cyclic nucleotide phosphodiesterases, and protein kinase A as therapeutic targets in ADPKD.

Hesperidin methyl chalcone interacts with NFκB Ser276 and inhibits zymosan-induced joint pain and inflammation, and RAW 264.7 macrophage activation

Arthritis can be defined as a painful musculoskeletal disorder that affects the joints. Hesperidin methyl chalcone (HMC) is a flavonoid with analgesic, anti-inflammatory, and antioxidant effects. However, its effects on a specific cell type and in the zymosan-induced inflammation are unknown. We aimed at evaluating the effects of HMC in a zymosan-induced arthritis model. A dose-response curve of HMC (10, 30, or 100 mg/kg) was performed to determine the most effective analgesic dose after intra-articular zymosan stimuli. Knee joint oedema was determined using a calliper. Leukocyte recruitment was performed by cell counting on knee joint wash as well as histopathological analysis. Oxidative stress was measured by colorimetric assays (GSH, FRAP, ABTS and NBT) and RT-qPCR (gp91^phox and HO-1 mRNA expression) performed. In vitro, oxidative stress was assessed by DCFDA assay using RAW 264.7 macrophages. Cytokine production was evaluated in vivo and in vitro by ELISA. In vitro NF-κB activation was analysed by immunofluorescence. We observed HMC reduced mechanical hypersensitivity and knee joint oedema, leukocyte recruitment, and pro-inflammatory cytokine levels. We also observed a reduction in zymosan-induced oxidative stress as per increase in total antioxidant capacity and reduction in gp91^phox and increase in HO-1 mRNA expression. Accordingly, total ROS production and macrophage NFκB activation were diminished. HMC interaction with NFκB p65 at Ser276 was revealed using molecular docking analysis. Thus, data presented in this work suggest the usefulness of HMC as an analgesic and anti-inflammatory in a zymosan-induced arthritis model, possibly by targeting NFκB activation in macrophages.

α2A -AR antagonism by BRL-44408 maleate attenuates acute lung injury in rats with downregulation of ERK1/2, p38MAPK, and p65 pathway

Acute respiratory distress syndrome (ARDS), characterized by acute hypoxic respiratory dysfunction or failure, is a manifestation of multiple organ failure in the lung, and the most common risk factor is sepsis. We previously showed that blocking α₂ -adrenoceptor (α₂ -AR) could attenuate lung injury induced by endotoxin in rats. α_2A -adrenoceptor (α_2A -AR), a subtype of α₂ -AR plays a key role in inflammatory diseases, but the mechanism remains unknown. Here, we explored the effect of BRL-44408 maleate (BRL), a specific α_2A -AR antagonist, on cecal ligation puncture (CLP)-induced ARDS in rats and the underlying mechanism. Preadministration of BRL-44408 maleate significantly alleviated CLP-induced histological injury, macrophage infiltration, inflammatory response, and wet/dry ratio in lung tissue. However, there was no statistical difference in survival rate between the CLP and CLP+BRL groups. Extracellular regulated protein kinase (ERK1/2), p38MAPK, and p65 were activated in the CLP group, and BRL-44408 maleate inhibited the activation of these signal molecules, c-Jun N-terminal kinase (JNK) and protein kinase A (PKA) showed no changes in activation between these two groups. BRL-44408 maleate decreased lipopolysaccharide (LPS)-induced expression of cytokines in NR8383 rat alveolar macrophages and reduced phosphorylation of ERK1/2, p38MAPK, and p65. JNK and PKA were not influenced by LPS. Together, these findings suggest that antagonism of α_2A -AR improves CLP-induced acute lung injury and involves the downregulation of ERK1/2, p38MAPK, and p65 pathway independent of the activation of JNK and PKA.

The Anti-Inflammatory Effects of Angiogenin in an Endotoxin Induced Uveitis in Rats

Angiogenin (ANG) is involved in the innate immune system and inflammatory disease. The aim of this study is to evaluate the anti-inflammatory effects of ANG in an endotoxin induced uveitis (EIU) rat model and the pathways involved. EIU rats were treated with balanced salt solution (BSS), a non-functional mutant ANG (mANG), or wild-type ANG (ANG). The integrity of the blood-aqueous barrier was evaluated by the infiltrating cell and protein concentrations in aqueous humor. Histopathology, Western blot, and real-time qRT-PCR of aqueous humor and ocular tissue were performed to analyze inflammatory cytokines and transcription factors. EIU treated with ANG had decreased inflammatory cells and protein concentrations in the anterior chamber. Compared to BSS and mANG, ANG treatment showed reduced expression of IL-1β, IL-8, TNF-α, and Myd88, while the expression of IL-4 and IL-10 was increased. Western blot of ANG treatment showed decreased expression of IL-6, inducible nitric oxide synthase (iNOS), IL-1β, TNF-α, and phosphorylated NF-κB and increased expression of IL-10. In conclusion, ANG seems to reduce effectively immune mediated inflammation in the EIU rat model by reducing the expression of proinflammatory cytokines, while increasing the expression of anti-inflammatory cytokines through pathways related to NF-κB. Therefore, ANG shows potential for effectively suppressing immune-inflammatory responses in vivo.

Natural Coumarin Derivative Esculetin Regulates Platelet Activation via Modulating NF-κB Signaling in Cyclic Nucleotide-Independent Manner

Esculetin, a natural coumarin derivative, shows exciting biological activities in a variety of cell and animal models. Our recent study demonstrated that esculetin exhibits antiplatelet effects by obstructing the phospholipase C γ2/protein kinase C cascade, hydroxyl radical formation, and Akt activation. In this study, we further examined the involvement of cyclic 3′-5′adenosine monophosphate/, vasodilator-stimulated phosphoprotein (VASP), integrin αIIbβ3, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), since cyclic nucleotides reduce the phosphorylation of VASP and activate NF-κB, subsequently inducing αIIbβ3 activation that significantly involves the platelet inhibitory pathways. We found that esculetin (50 and 80 µM) did not significantly affect fibrinogen-induced aggregation of elastase-treated platelets; however, it markedly blocked integrin αIIbβ3 activation by interrupting the binding of fluorescein isothiocyanate-labeled PAC-1. In addition, neither ODQ nor SQ22536 significantly reversed esculetin-mediated antiplatelet activity stimulated by collagen. Nitroglycerin and prostaglandin E1 significantly increased VASP phosphorylation, but esculetin had no effect in this reaction, the values being almost identical with those of normal platelets. Furthermore, esculetin, at its maximum concentration of 80 μM significantly reduced the phosphorylation of IκBα and p65 and reversed IκBα degradation in collagen-induced platelets. These results suggest that the NF-κB-dependent αIIbβ3 inhibition of esculetin might represent a novel feedback inhibitory mechanism to regulate platelet functions.

Fucoidan from marine brown algae attenuates pancreatic cancer progression by regulating p53 - NFκB crosstalk

Poor pancreatic cancer (PC) prognosis has been attributed to its resistance to apoptosis and propensity for early systemic dissemination. Existing therapeutic strategies are often circumvented by the molecular crosstalk between cell-signalling pathways. p53 is mutated in more than 50% of PC and NFκB is constitutively activated in therapy-resistant residual disease; these mutations and activations account for the avoidance of cell death and metastasis. Recently, we demonstrated the anti-PC potential of fucoidan extract from marine brown alga, Turbinaria conoides (J. Agardh) Kützing (Sargassaceae). In this study, we aimed to characterize the active fractions of fucoidan extract to identify their select anti-PC efficacy, and to define the mechanism(s) involved. Five fractions of fucoidan isolated by ion exchange chromatography were tested for their potential in genetically diverse human PC cell lines. All fractions exerted significant dose-dependent and time-dependent regulation of cell survival. Fucoidans induced apoptosis, activated caspase -3, -8 and -9, and cleaved Poly ADP ribose polymerase (PARP). Pathway-specific transcriptional analysis recognized inhibition of 57 and 38 nuclear factor κB (NFκB) pathway molecules with fucoidan-F5 in MiaPaCa-2 and Panc-1 cells, respectively. In addition, fucoidan-F5 inhibited both the constitutive and Tumor necrosis factor-α (TNFα)-mediated NFκB DNA-binding activity in PC cells. Upregulation of cytoplasmic IκB levels and significant reduction of NFκB-dependent luciferase activity further substantiate the inhibitory potential of seaweed fucoidans on NFκB. Moreover, fucoidan(s) treatment increased cellular p53 in PC cells and reverted NFκB forced-expression-related p53 reduction. The results suggest that fucoidan regulates PC progression and that fucoidans may target p53-NFκB crosstalk and dictate apoptosis in PC cells.

Oncogenic Ras mutant causes the hyperactivation of NF-κB via acceleration of its transcriptional activation

It is well established that nuclear factor κB (NF-κB) acts as one of the most important transcription factors for tumor initiation and progression, as it both protects cells from apoptotic/necrotic signals and accelerates angiogenesis and tumor metastasis, which is mediated via the expression of target genes. However, it has not yet been clarified how oncogenic signals accelerate the activation of NF-κB. In the current study, we utilized untransformed NIH-3T3 cells stably harboring a κB-driven luciferase gene to show that an oncogenic mutant of Ras GTPase augmented TNFα-induced NF-κB activation. Notably, enforced expression of cyclin-dependent kinase inhibitors, such as p27^Kip1 and p21^Cip1 , effectively canceled the accelerated activation of NF-κB, suggesting that oncogenic Ras-induced cell cycle progression is essential for the hyperactivation of NF-κB. Furthermore, we found that Ras (G12V) augmented the transcriptional activation of NF-κB, and this activation required the p38 MAP kinase. We observed that a downstream kinase of p38 MAP kinase, MSK1, was activated by Ras (G12V) and catalyzed the phosphorylation of p65/RelA at Ser-276, which is critical for its transcriptional activation. Significantly, phosphorylation of the p65/RelA subunit at Ser-276 was elevated in patient samples of colorectal cancer harboring oncogenic mutations of the K-Ras gene, and the expression levels of NF-κB target genes were drastically enhanced in several cancer tissues. These observations strongly suggest that oncogenic signal-induced acceleration of NF-κB activation is caused by activation of the p38 MAP kinase-MSK1 signaling axis and by cell cycle progression in cancer cells.

Crth2 receptor signaling down-regulates lipopolysaccharide-induced NF-κB activation in murine macrophages via changes in intracellular calcium

Prostaglandin D₂ and its cyclopentenone metabolites [cyclopentenone prostaglandins (CyPGs)], Δ¹²prostaglandin J₂ and 15-deoxy-Δ^12,14-prostaglandin J₂, act through 2 GPCRs, d-type prostanoid 1 and the chemoattractant receptor homologous molecule expressed on type 2 T-helper cells (Crth2). In addition to its role in allergy and asthma, the role of Crth2 in the resolution of inflammation, to mediate the proresolving functions of endogenous CyPGs, is not well understood. We investigated the regulation of LPS or zymosan-induced inflammatory response by signals from the Crth2 receptor in macrophages that lack Crth2 expression [knockout (KO)]. Increased expression of proinflammatory genes, including Tnf-α, was observed in Crth2 KO cells. Targeting the endogenous biosynthetic pathway of CyPGs with indomethacin or HQL79, which inhibit cyclooxygenases or hematopoietic prostaglandin D synthase, respectively, or use of Crth2 antagonists recapitulated the proinflammatory phenotype as in Crth2 KO cells. Ligand-dependent activation of Crth2 by 13,14-dihydro-15-keto-prostaglandin D₂ increased Ca²⁺ influx through store-operated Ca²⁺ entry (SOCE) accompanied by the up-regulation of stromal interaction molecule 1 and calcium release-activated calcium modulator 1 expression, suggesting that the proresolution effects of CyPG-dependent activation of SOCE could be mediated by Crth2 during inflammation. Interestingly, Crth2 signaling down-regulated the Ca²⁺-regulated heat stable protein 1 that stabilizes Tnf-α mRNA via the increased expression of microRNA 155 to dampen inflammatory responses triggered through the TNF-α-NF-κB axis. In summary, these studies present a novel regulatory role for Crth2 during inflammatory response in macrophages.-Diwakar, B. T., Yoast, R., Nettleford, S., Qian, F., Lee, T.-J., Berry, S., Huffnagle, I., Rossi, R. M., Trebak, M., Paulson, R. F., Prabhu, K. S. Crth2 receptor signaling down-regulates lipopolysaccharide-induced NF-κB activation in murine macrophages via changes in intracellular calcium.

Roles of the hexosamine biosynthetic pathway and pentose phosphate pathway in bile acid-induced cancer development

Esophageal squamous cell carcinomas (ESCCs) as well as adenocarcinomas (EACs) were developed in rat duodenal contents reflux models (reflux model). The present study aimed to shed light on the mechanism by which bile acid stimulation causes cancer onset and progression. Metabolomics analyses were performed on samples of neoplastic and nonneoplastic tissues from reflux models, and K14D, cultivated from a nonmetastatic, primary ESCC, and ESCC-DR, established from a metastatic thoracic lesion. ESCC-DRtca2M was prepared by treating ESCC-DR cells with taurocholic acid (TCA) to accelerate cancer progression. The lines were subjected to comprehensive genomic analyses. In addition, protein expression levels of glucose-6-phosphate dehydrogenase (G6PD), nuclear factor kappa B (NF-κB) (p65) and O-linked N-Acetylglucosamine (O-GlcNAc) were compared among lines. Cancers developed in the reflux models exhibited greater hexosamine biosynthesis pathway (HBP) activation compared with the nonneoplastic tissues. Expression of O-GlcNAc transferase (OGT) increased considerably in both ESCC and EAC compared with nonneoplastic squamous epithelium. Conversely, cell line-based experiments revealed the greater activation of the pentose phosphate pathway (PPP) at higher degrees of malignancy. G6PD overexpression in response to TCA exposure was observed. Both NF-κB (p65) and O-GlcNAc were expressed more highly in ESCC-DRtca2M than in the other cell lines. Moreover, ESCC-DRtca2M cells had additional chromosomal abnormalities in excess of ESCC-DR cells. Overall, glucose metabolism was upregulated in both esophageal cancer tissue and cell lines. While bile acids are not mutagenic, chronic exposure seems to trigger NF-κB(p65) activation, potentially inducing genetic mutations as well as facilitating carcinogenesis and cancer progression. Glucose metabolism was upregulated in both esophageal cancer tissue and cell lines, and the HBP was activated in the former. The cell line-based experiments demonstrated upregulation of the pentose phosphate pathway (PPP) at higher degrees of malignancy. While bile acids are not mutagenic, chronic exposure seems to trigger G6PD overexpression and NF-κB (p65) activation, potentially inducing genetic mutations as well as facilitating carcinogenesis and cancer progression.

Critical roles of ARHGAP36 as a signal transduction mediator of Shh pathway in lateral motor columnar specification

During spinal cord development, Sonic hedgehog (Shh), secreted from the floor plate, plays an important role in the production of motor neurons by patterning the ventral neural tube, which establishes MN progenitor identity. It remains unknown, however, if Shh signaling plays a role in generating columnar diversity of MNs that connect distinct target muscles. Here, we report that Shh, expressed in MNs, is essential for the formation of lateral motor column (LMC) neurons in vertebrate spinal cord. This novel activity of Shh is mediated by its downstream effector ARHGAP36, whose expression is directly induced by the MN-specific transcription factor complex Isl1-Lhx3. Furthermore, we found that AKT stimulates the Shh activity to induce LMC MNs through the stabilization of ARHGAP36 proteins. Taken together, our data reveal that Shh, secreted from MNs, plays a crucial role in generating MN diversity via a regulatory axis of Shh-AKT-ARHGAP36 in the developing mouse spinal cord.

Branched Short-Chain Fatty Acid Isovaleric Acid Causes Colonic Smooth Muscle Relaxation via cAMP/PKA Pathway

BACKGROUND

Isovaleric acid (IVA) is a 5-carbon branched-chain fatty acid present in fermented foods and produced in the colon by bacterial fermentation of leucine. We previously reported that the shorter, straight-chain fatty acids acetate, propionate and butyrate differentially affect colonic motility; however, the effect of branched-chain fatty acids on gut smooth muscle and motility is unknown.

AIMS

To determine the effect of IVA on contractility of colonic smooth muscle.

METHODS

Murine colonic segments were placed in a longitudinal orientation in organ baths in Krebs buffer and fastened to force transducers. Segments were contracted with acetylcholine (ACh), and the effects of IVA on ACh-induced contraction were measured in the absence and presence of tetrodotoxin (TTx) or inhibitors of nitric oxide synthase [L-N-nitroarginine (L-NNA)] or adenylate cyclase (SQ22536). The effect of IVA on ACh-induced contraction was also measured in isolated muscle cells in the presence or absence of SQ22536 or protein kinase A (PKA) inhibitor (H-89). Direct activation of PKA was measured in isolated muscle cells.

RESULTS

In colonic segments, ACh-induced contraction was inhibited by IVA in a concentration-dependent fashion; the IVA response was not affected by TTx or L-NNA but inhibited by SQ22536. Similarly, in isolated colonic muscle cells, ACh-induced contraction was inhibited by IVA in a concentration-dependent fashion and the effect blocked by SQ22536 and H-89. IVA also increased PKA activity in isolated smooth muscle cells.

CONCLUSIONS

The branched-chain fatty acid IVA acts directly on colonic smooth muscle and causes muscle relaxation via the PKA pathway.

NOD1: An Interface Between Innate Immunity and Insulin Resistance

Insulin resistance is driven, in part, by activation of the innate immune system. We have discussed the evidence linking nucleotide-binding oligomerization domain (NOD)1, an intracellular pattern recognition receptor, to the onset and progression of obesity-induced insulin resistance. On a molecular level, crosstalk between downstream NOD1 effectors and the insulin receptor pathway inhibits insulin signaling, potentially through reduced insulin receptor substrate action. In vivo studies have demonstrated that NOD1 activation induces peripheral, hepatic, and whole-body insulin resistance. Also, NOD1-deficient models are protected from high-fat diet (HFD)-induced insulin resistance. Moreover, hematopoietic NOD1 deficiency prevented HFD-induced changes in proinflammatory macrophage polarization status, thus protecting against the development of metabolic inflammation and insulin resistance. Serum from HFD-fed mice activated NOD1 signaling ex vivo; however, the molecular identity of the activating factors remains unclear. Many have proposed that an HFD changes the gut permeability, resulting in increased translocation of bacterial fragments and increased circulating NOD1 ligands. In contrast, others have suggested that NOD1 ligands are endogenous and potentially lipid-derived metabolites produced during states of nutrient overload. Nevertheless, that NOD1 contributes to the development of insulin resistance, and that NOD1-based therapy might provide benefit, is an exciting advancement in metabolic research.

Natural chromones as potential anti-inflammatory agents: Pharmacological properties and related mechanisms

Chromones are a group of natural substances with a diversity of biological activities. Herein we assessed the pharmacological potential of three chromones (1, 2 and 3) isolated from Dictyoloma vandellianum as anti-inflammatory agents using in vitro and in vivo approaches. During in vitro screening, the production of NO and cytokines by macrophages stimulated with LPS and IFN-γ was inhibited by all chromones at concentrations (5-20 μM) that did not induce cytotoxicity. Analysis of pharmacokinetic parameters (in vitro half-life and intrinsic clearance) using human liver microsomes revealed that 3 has a superior pharmacokinetic profile, compared to 1 and 2. Treatment with 3 (100 mg/kg, ip) did not affect the mice motor performance, while 1 and 2 induced motor deficit. Taking into account the pharmacokinetic profile and absence of motor impairment, 3 was selected for further pharmacological characterization. Corroborating the data from in vitro screening, treatment of cell cultures with 3 (5-20 μM) reduced TNF-α, IL-6 and IL-1β production by stimulated macrophages. In the complete Freund's adjuvant-induced paw inflammation model in mice, 3 (25 and 50 mg/kg, ip) inhibited mechanical hyperalgesia, edema and cytokine production/release (IL-1β, IL-6 and TNF-α). 3 (5-20 μM) also reduced the transcriptional activity of NF-κB in stimulated macrophages. Furthermore, treatment with RU486, a glucocorticoid receptor (GR) antagonist, partially prevented the inhibitory effect of 3 on macrophages, indicating that this chromone exerts its anti-inflammatory effects in part through the activation of GR. The results presented herein demonstrate the pharmacological potential of natural chromones, highlighting 3 as a possible candidate for the drug discovery process targeting new anti-inflammatory drugs.

IL-1β and TNFα Differentially Influence NF-κB Activity and FasL-Induced Apoptosis in Primary Murine Hepatocytes During LPS-Induced Inflammation

Macrophage-derived cytokines largely influence the behavior of hepatocytes during an inflammatory response. We previously reported that both TNFα and IL-1β, which are released by macrophages upon LPS stimulation, affect Fas ligand (FasL)-induced apoptotic signaling. Whereas TNFα preincubation leads to elevated levels of caspase-3 activity and cell death, pretreatment with IL-1β induces increased caspase-3 activity but keeps cells alive. We now report that IL-1β and TNFα differentially influence NF-κB activity resulting in a differential upregulation of target genes, which may contribute to the distinct effects on cell viability. A reduced NF-κB activation model was established to further investigate the molecular mechanisms which determine the distinct cell fate decisions after IL-1β and TNFα stimulation. To study this aspect in a more physiological setting, we used supernatants from LPS-stimulated bone marrow-derived macrophages (BMDMs). The treatment of hepatocytes with the BMDM supernatant, which contains both IL-1β and TNFα, sensitized to FasL-induced caspase-3 activation and cell death. However, when TNFα action was blocked by neutralizing antibodies, cell viability after stimulation with the BMDM supernatant and FasL increased as compared to single FasL stimulation. This indicates the important role of TNFα in the sensitization of apoptosis in hepatocytes. These results give first insights into the complex interplay between macrophages and hepatocytes which may influence life/death decisions of hepatocytes during an inflammatory reaction of the liver in response to a bacterial infection.

Celecoxib Protects Hyperoxia-Induced Lung Injury via NF-κB and AQP1

Objective: There is an increasing incidence of bronchopulmonary dysplasia (BDP) in preterm infants in China, which is the key issue affecting their survival rate and life quality. This study was performed to better understand the mechanism of protective effect of celecoxib on hyperoxia induced injury. Methods: Hyperoxia BPD model was established using newborn Sprague-Dawley (SD) rats exposed to high O₂ level (85%). Celecoxib treatment was also conducted. Histology of lung tissue samples were analyzed. Functional studies were systematically performed using the lung tissues and A549 cells. Results: Hyperoxia disrupted lung development in SD rats. Celecoxib alleviated the damaged lung development. NF-κB and Aquaporin (AQP) 1 were identified as the pathways in the hyperoxia-induced lung injury. We have shown that hyperoxia activated NF-κB pathway through increased nucleus translocation and repressed AQP1 expression. On the contrary, celecoxib inhibited NF-κB phosphorylation and nucleus translocation and increased AQP1 expression through inhibiting COX2 activity. Additionally, celecoxib also rescued apoptosis induced by hyperoxia. Conclusion: Our study identified NF-κB and AQP1 as the pathways in the hyperoxia-induced lung injury in the hyperoxia BPD model SD rats and it provided a better understanding of the protective effect of celecoxib. It suggests NF-κB and AQP1 may be as potential targets for treating newborns with BPD.

Immune response in the relapsing-remitting experimental autoimmune encephalomyelitis in mice: The role of the NF-κB signaling pathway

Characteristics of the mouse model of relapsing-remitting experimental autoimmune encephalomyelitis (rEAE) closely resemble manifestations of multiple sclerosis in humans. In the present study, we investigated the mechanisms of inflammatory response, focusing on NF-κB pathway activation. Cytokine response in rEAE mice was multiphasic: the early phase was characterized by the increase in interferon-γ level in plasma. In the later stage, the level of interleukin-17, but not of interferon-γ, was increased. The early phase of rEAE was also accompanied by increased RelA/p65 phosphorylation at Ser276 in spleen cells, whereas the rEAE maintenance phase was characterized by RelA/p65 phosphorylation at Ser536 and IKK phosphorylation. The IKKα/β inhibitor reduced interleukin-17 and interferon-γ levels in plasma and alleviated rEAE symptoms. The IKKα/β inhibitor decreased IKK and p65(Ser536) phosphorylation, but doubled p65(Ser276) phosphorylation in rEAE mice. The increased RelA/p65(Ser276) phosphorylation coincided in time with the production of interferon-γ, Hsp72, and the early phase of IL-17 generation, whereas increased RelA/p65(Ser536) phosphorylation coincided with the activation of IKK, SAPK/JNK, and p53, as well as the late phase of IL-17 production, indicating the role of the RelA/p65 phosphorylation events in the induction and maintenance of rEAE.

Glucose deprivation activates a cAMP-independent protein kinase from Trypanosoma equiperdum

Kemptide (sequence: LRRASLG) is a synthetic peptide holding the consensus recognition site for the catalytic subunit of the cAMP-dependent protein kinase (PKA). cAMP-independent protein kinases that phosphorylate kemptide were stimulated in Trypanosoma equiperdum following glucose deprivation. An enriched kemptide kinase-containing fraction was isolated from glucose-starved parasites using sedimentation throughout a sucrose gradient, followed by sequential chromatography on diethylaminoethyl-Sepharose and Sephacryl S-300. The trypanosome protein possesses a molecular mass of 39.07-51.73 kDa, a Stokes radius of 27.4 Ǻ, a sedimentation coefficient of 4.06 S and a globular shape with a frictional ratio f/fo = 1.22-1.25. Optimal enzymatic activity was achieved at 37 °C and pH 8.0, and kinetic studies showed Km values for ATP and kemptide of 11.8 ± 4.1 and 24.7 ± 3.8 µm, respectively. The parasite enzyme uses ATP and Mg2+ and was inhibited by other nucleotides and/or analogues of ATP, such as cAMP, AMP, ADP, GMP, GDP, GTP, CTP, β,γ-imidoadenosine 5'-triphosphate and 5'-[p-(fluorosulfonyl)benzoyl] adenosine, and by other divalent cations, such as Zn2+, Mn2+, Co2+, Cu2+, Ca2+ and Fe2+. Additionally, the trypanosome kinase was inhibited by the PKA-specific heat-stable peptide inhibitor PKI-α. This study is the first biochemical and enzymatic characterization of a protein kinase from T. equiperdum.

Mechanisms of NF-κB p65 and strategies for therapeutic manipulation

The transcription factor NF-κB is a critical regulator of immune and inflammatory responses. In mammals, the NF-κB/Rel family comprises five members: p50, p52, p65 (Rel-A), c-Rel, and Rel-B proteins, which form homo- or heterodimers and remain as an inactive complex with the inhibitory molecules called IκB proteins in resting cells. Two distinct NF-κB signaling pathways have been described: 1) the canonical pathway primarily activated by pathogens and inflammatory mediators, and 2) the noncanonical pathway mostly activated by developmental cues. The most abundant form of NF-κB activated by pathologic stimuli via the canonical pathway is the p65:p50 heterodimer. Disproportionate increase in activated p65 and subsequent transactivation of effector molecules is integral to the pathogenesis of many chronic diseases such as the rheumatoid arthritis, inflammatory bowel disease, multiple sclerosis, and even neurodegenerative pathologies. Hence, the NF-κB p65 signaling pathway has been a pivotal point for intense drug discovery and development. This review begins with an overview of p65-mediated signaling followed by discussion of strategies that directly target NF-κB p65 in the context of chronic inflammation.

Potent immunosuppressive activity of a phosphodiesterase-4 inhibitor N-acylhydrazone in models of lipopolysaccharide-induced shock and delayed-type hypersensitivity reaction

Immunosuppressive drugs are widely used for the treatment of immune-mediated diseases and inflammation, but the toxicity and side effects of the available immunosuppressors make the search of new agents of great relevance. Here, we evaluated the immunomodulatory activity of an N-acylhydrazone derivative, (E)-N'-(3,4-dimethoxybenzylidene)-4-methoxybenzohydrazide (LASSBio-1386), a phosphodiesterase-4 (PDE-4) inhibitor. LASSBio-1386 inhibited lymphocyte activation in a concentration-dependent fashion, decreasing lymphoproliferation and IFN-γ and IL-2 production stimulated by anti-CD3/CD28 mAbs or concanavalin A (Con A) and inducing cell-cycle arrest in the G0/G1 phase. These effects were not blocked by RU486, a glucocorticoid receptor (GR) antagonist, indicating an effect independent of glucocorticoid receptor activation. Combination index-isobologram analysis indicates a synergistic effect between LASSBio-1386 and dexamethasone in lymphoproliferation inhibition. LASSBio-1386 presented immunomodulatory action in macrophage cultures, as observed by a significant and concentration-dependent decrease in NO and TNF-α production, an effect achieved by reducing IĸB expression and NF-κB activation. In the mouse model of endotoxic shock, LASSBio-1386 at 50 and 100 mg/kg protected 50 and 85% of mice against LPS-induced lethality, respectively. In agreement to its in vitro action, treatment with 100 mg/kg of LASSBio-1386 reduced TNF-α and IL-1β serum levels, while increased IL-6 and IL-10. Finally, LASSBio-1386 reduced the paw edema in a BSA-induced delayed-type hypersensitivity model. These findings demonstrate the immunomodulatory and immunosuppressant effects of LASSBio-1386 and indicate this molecule is a promising pharmacologic agent for immune-mediated diseases.