Prostaglandin F2α receptor antagonist attenuates LPS-induced systemic inflammatory response in mice

Subconjunctival Administration of an Adeno-Associated Virus Expressing Stanniocalcin-1 Provides Sustained Intraocular Pressure Reduction in Mice

Purpose

To investigate subconjunctival administration of a single-stranded, adeno-associated virus, serotype 2, engineered to express stanniocalcin-1 with a FLAG tag (ssAAV2-STC-1-FLAG) as a novel sustained (IOP) lowering agent with a reduced ocular surface side effect profile.

Design

In vivo preclinical investigation in mice.

Subjects

C57BL/6J, DBA/2J, prostaglandin F (FP) receptor knockout mice.

Methods

Normotensive C57BL/6J mice were treated with a subconjunctival injection of ssAAV2-STC-1-FLAG (2 μL; 6 × 109 viral genomes [VGs]) in 1 eye and the same volume and concentration of ssAAV2-green fluorescent protein (GFP) or the same volume of phosphate-buffered saline in the fellow eye. Ocular hypertensive DBA/2J mice were subconjunctivally injected with 6 × 109 VGs of ssAAV2-STC-1-FLAG or ssAAV2-GFP. Steroid-mediated ocular hypertension was induced in C57BL/6J mice with weekly injections of dexamethasone into the conjunctival fornix, and mice were then injected subconjunctivally with 6 × 109 VGs of ssAAV2-STC-1-FLAG or ssAAV2-GFP. Prostaglandin F receptor knockout mice were injected subconjunctivally with 6 × 109 VGs of ssAAV2-STC-1-FLAG or phosphate-buffered saline. An identical vector was constructed without the FLAG tag (ssAAV2-STC-1) and evaluated in normotensive C57BL/6J mice. Intraocular pressure was assessed using the Tonolab tonometer for all experiments. Tumor necrosis factor alpha (TNFα), a marker of ocular surface inflammation, was compared between subconjunctivally delivered ssAAV2-STC-1-FLAG and other treatments including daily topical latanoprost.

Main Outcome Measures

Intraocular pressure assessment.

Results

Subconjunctival delivery of ssAAV2-STC-1-FLAG significantly reduced IOP for 10 weeks post injection in normotensive mice. Maximal IOP reduction was seen at week 3 postinjection (17.4%; 17.1 ± 0.8 vs. 14.1 ± 0.8 mmHg, P < 0.001). After the IOP-lowering effect had waned, a second injection restored the ocular hypotensive effect. Subconjunctivally delivered ssAAV2-STC-1-FLAG lowered IOP in DBA/2J mice (16.9%; 17.8 ± 2.0 vs. 14.8 ± 0.9 mmHg, P < 0.001) and steroid-mediated ocular hypertensive mice (20.0%; 19.0 ± 0.6 vs. 15.2 ± 0.7 mmHg, P < 0.001) over the experimental period. This construct also reduced IOP to a similar extent in wild-type (15.9%) and FP receptor knockout (15.7%) mice compared with the fellow eye. A related construct also lowered IOP without the FLAG tag in a similar manner. Reduction in conjunctival TNFα was seen when comparing subconjunctivally delivered ssAAV2-STC-1-FLAG to daily topical latanoprost.

Conclusions

Subconjunctival delivery of the STC-1 transgene with a vector system may represent a novel treatment strategy for sustained IOP reduction and improved ocular tolerability that also avoids the daily dosing requirements of currently available medications.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Prostacyclin synthase deficiency exacerbates systemic inflammatory responses in lipopolysaccharide-induced septic shock in mice

OBJECTIVES

Sepsis is a systemic inflammatory disorder characterized by life-threateningorgan dysfunction resulting from a dysregulated host response to infection. Prostacyclin (PGI2) is a bioactive lipid produced by PGI synthase (PGIS) and is known to play important roles in inflammatory reactions as well as cardiovascular regulation. However, little is known about the roles of PGIS and PGI2 in systemic inflammatory responses such as septic shock.

METHODOLOGY

Systemic inflammation was induced by intraperitoneal injection of 5 mg/kg lipopolysaccharide (LPS) in wild type (WT) or PGIS knockout (KO) mice. Selexipag, a selective PGI2 receptor (IP) agonist, was administered 2 h before LPS injection and again given every 12 h for 3 days.

RESULTS

Intraperitoneal injection of LPS induced diarrhea, shivering and hypothermia. These symptoms were more severe in PGIS KO mice than in WT micqe. The expression of Tnf and Il6 genes was notably increased in PGIS KO mice. In contrast, over 95% of WT mice survived 72 h after the administration of LPS, whereas all of the PGIS KO mice had succumbed by that time. The mortality rate of LPS-administrated PGIS KO mice was improved by selexipag administration.

CONCLUSION

Our study suggests that PGIS-derived PGI2 negatively regulates LPS-induced symptoms via the IP receptor. PGIS-derived PGI2-IP signaling axis may be a new drug target for systemic inflammation in septic shock.

Roles of prostaglandins in immunosuppression

Prostaglandins (PGs) play a crucial and multifaceted role in various physiological processes such as intercellular signaling, inflammation regulation, neurotransmission, vasodilation, vasoconstriction, and reproductive functions. The diversity and biological significance of these effects are contingent upon the specific types or subtypes of PGs, with each PG playing a crucial role in distinct physiological and pathological processes. Particularly within the immune system, PGs are essential in modulating the function of immune cells and the magnitude and orientation of immune responses. Hence, a comprehensive comprehension of the functions PG signaling pathways in immunosuppressive regulation holds substantial clinical relevance for disease prevention and treatment strategies. The manuscript provides a review of recent developments in PG signaling in immunosuppressive regulation. Furthermore, the potential clinical applications of PGs in immunosuppression are also discussed. While research into the immunosuppressive effects of PGs required further exploration, targeted therapies against their immunosuppressive pathways might open new avenues for disease prevention and treatment.

Physiologically based pharmacokinetic model for predicting the biodistribution of albumin nanoparticles after induction and recovery from acute lung injury

The application of nanomedicine in the treatment of acute lung injury (ALI) has great potential for the development of new therapeutic strategies. To gain insight into the kinetics of nanocarrier distribution upon time-dependent changes in tissue permeability after ALI induction in mice, we developed a physiologically based pharmacokinetic model for albumin nanoparticles (ANP). The model was calibrated using data from mice treated with intraperitoneal LPS (6 mg/kg), followed by intravenous ANP (0.5 mg/mouse or about 20.8 mg/kg) at 0.5, 6, and 24 h. The simulation results reproduced the experimental observations and indicated that the accumulation of ANP in the lungs increased, reaching a peak 6 h after LPS injury, whereas it decreased in the liver, kidney, and spleen. The model predicted that LPS caused an immediate (within the first 30 min) dramatic increase in lung and kidney tissue permeability, whereas splenic tissue permeability gradually increased over 24 h after LPS injection. This information can be used to design new therapies targeting specific organs affected by bacterial infections and potentially by other inflammatory insults.

PLK1 inhibition dampens NLRP3 inflammasome-elicited response in inflammatory disease models

Unabated activation of the NLR family pyrin domain-containing 3 (NLRP3) inflammasome is linked with the pathogenesis of various inflammatory disorders. Polo-like kinase 1 (PLK1) has been widely studied for its role in mitosis. Here, using both pharmacological and genetic approaches, we demonstrate that PLK1 promoted NLRP3 inflammasome activation at cell interphase. Using an unbiased proximity-dependent biotin identification (Bio-ID) screen for the PLK1 interactome in macrophages, we show an enhanced proximal association of NLRP3 with PLK1 upon NLRP3 inflammasome activation. We further confirmed the interaction between PLK1 and NLRP3 and identified the interacting domains. Mechanistically, we show that PLK1 orchestrated the microtubule-organizing center (MTOC) structure and NLRP3 subcellular positioning upon inflammasome activation. Treatment with a selective PLK1 kinase inhibitor suppressed IL-1β production in in vivo inflammatory models, including LPS-induced endotoxemia and monosodium urate-induced peritonitis in mice. Our results uncover a role of PLK1 in regulating NLRP3 inflammasome activation during interphase and identify pharmacological inhibition of PLK1 as a potential therapeutic strategy for inflammatory diseases with excessive NLRP3 inflammasome activation.

Production profile of lipid mediators in conjunctival lavage fluid in allergic and infectious conjunctivitis in guinea pigs

Introduction

Conjunctivitis is a major ocular disease classified into allergic or infectious. The pathological features of conjunctivitis are not fully understood despite its high morbidity rate; thus, its differentiation can be difficult.

Materials and methods

We used ovalbumin-induced allergic conjunctivitis and lipopolysaccharide-induced infectious conjunctivitis models of guinea pigs. Both models showed conjunctival swelling. Histological studies revealed that numerous eosinophils infiltrated the conjunctiva in the allergic model, whereas neutrophils infiltrated the conjunctiva in the infectious model. We collected conjunctival lavage fluid (COLF) and comprehensively analyzed lipid production using liquid chromatography-tandem mass spectrometry.

Results

COLF showed increase of 20 and 12 lipid species levels in the allergic and infectious models, respectively. Specifically, the levels of a major allergic mediator, prostaglandin D₂ and its three metabolites and several cytochrome P450-catalyzed lipids increased in the allergic model. In the infectious model, the levels of prostaglandin E₂ and 8-iso-prostaglandin E₂ increased, indicating tissue inflammation. Moreover, the level of 12-oxo-eicosatetraenoic acid, a lipoxygenase metabolite, increased in the infectious model.

Conclusion

These differences in lipid production in the COLF reflected the pathological features of allergic and infectious conjunctivitis.

Lactobacillus reuteri improves the development and maturation of fecal microbiota in piglets through mother-to-infant microbe and metabolite vertical transmission

BACKGROUND

The immature neonatal fecal microbiota substantially impacts the development of gut health and greatly increases the risk of disease. Developing effective strategies to modulate the development of neonatal fecal microbiota has great significance. Herein, we investigated whether the maternal dietary supplementation and oral administration of Lactobacillus reuteri could effectively promote the development and maturation of the fecal microbiome in piglets from birth to weaning.

RESULTS

Metagenomic analysis of colostrum showed that maternal dietary L. reuteri supplementation influenced the overall microbiota composition, decreased the abundance of the phylum Proteobacteria and increased that of the species Bifidobacterium choerinum. KEGG pathway analysis revealed that maternal L. reuteri supplementation enriched the lysine biosynthesis and glycolysis/gluconeogenesis pathways and downregulated the bacterial invasion of epithelial cells in the colostrum. In addition, L. reuteri supplementation significantly altered the metabolite features and modules in umbilical cord blood serum based on metabolomics. Further, a significant covariation was observed between these differential metabolites and the species in colostrum. Maternal dietary L. reuteri supplementation also significantly influenced the microbiota composition and increased the meconium abundance of beneficial bacteria (such as Romboutsia, Lactobacillus, Blautia, Butyricicoccus, and Ruminococcus), some of which were markedly associated with several differential metabolites in umbilical cord blood serum between two groups. Notably, both the maternal dietary supplementation and oral intake of L. reuteri had strong impacts on the overall microbial composition and maturation of fecal microbiota in piglets during early life, and these effects were dependent on the growth stage. Oral administration of L. reuteri promoted diarrhea resistance in neonates, while maternal supplementation of L. reuteri enhanced the abilities of antioxidants and decreased inflammation. Moreover, the administration of L. reuteri via both methods in combination improved the growth performances of piglets.

CONCLUSION

Overall, our data demonstrated that L. reuteri had the ability to modulate the composition of fecal microbiota in newborn piglets by influencing the microbial community and functional composition in the colostrum and by altering several key metabolites in the umbilical cord blood serum. Also, both the maternal dietary supplementation and oral administration of L. reuteri effectively promoted the development and maturation of the fecal microbiome in piglets during early life. Both the maternal dietary supplementation and oral administration of L. reuteri in combination optimized the growth performances of piglets. Video Abstract.

Bullatine A exerts anti-inflammatory effects by inhibiting the ROS/JNK/NF-κB pathway and attenuating systemic inflammatory responses in mice

CONTEXT

Aconiti brachypodi Radix (Xue-shang-yi-zhi-hao) is a traditional Chinese herbal medicine that is capable of anti-analgesic and anti-inflammatory effects. Bullatine A (BA) is one of the major active ingredients of this plant, and most of the previous studies reported that it has anti-analgesic effects. However, the mechanism of BA anti-inflammatory remains unclear.

OBJECTIVE

This study investigates the anti-inflammatory activities of BA, both in vitro and in vivo, and elucidates its mechanism.

MATERIALS AND METHODS

In vitro, BA (10, 20, 40 and 80 μM) was added to 1 µg/mL of lipopolysaccharide (LPS)-activated microglia BV2 cells and immortalized murine bone marrow-derived macrophages, respectively. After 6 h, the mRNA and protein levels of inflammatory factors were determined by real-time quantitative PCR and western blotting. In vivo, C57BL/6 mice were randomly divided into control, model (5 mg/kg dose of LPS) and treated groups (LPS with 5, 10 or 20 mg/kg dose of BA) to evaluate the anti-inflammatory efficacy of BA.

RESULTS

BA significantly inhibited LPS-induced expression of inflammatory factors, such as IL-1β, IL-6, TNF-α, inducible nitric oxide synthase (iNOS) and COX-2. Further investigations showed that BA reduced the translocation of NF-κB p65 (38.5%, p < 0.01). BA also reduced the phosphorylation of c-Jun N-terminal kinase (JNK) (11.2%, p < 0.05) and reactive oxygen species (ROS) generation (24.2%, p < 0.01). Furthermore, BA treatment attenuated the LPS-primed inflammatory response and liver and lung damage in vivo.

CONCLUSIONS

BA can inhibit the inflammatory response in part through the ROS/JNK/NF-κB signalling pathway, providing a theoretical basis for the clinical application of BA in the treatment of periphery inflammatory diseases.

Prostaglandins and non-steroidal anti-inflammatory drugs in Covid-19

In response to different viral infections, including SARS-CoV-2 infection, pro-inflammatory, anti-inflammatory cytokines, and bioactive lipids are released from infected and immune cells. One of the most critical bioactive lipids is prostaglandins (PGs) which favor perseverance of inflammation leading to chronic inflammation as PGs act as cytokine amplifiers. PGs trigger the release of pro-inflammatory cytokines, activate Th cells, recruit immune cells, and increase the expression of pro-inflammatory genes. Therefore, PGs may induce acute and chronic inflammations in various inflammatory disorders and viral infections like SARS-CoV-2. PGs are mainly inhibited by non-steroidal anti-inflammatory drugs (NSAIDs) by blocking cyclooxygenase enzymes (COXs), which involve PG synthesis. NSAIDs reduce inflammation by selective or non-selective blocking activity of COX2 or COX1/2, respectively. In the Covid-19 era, there is a tremendous controversy regarding the use of NSAIDs in the management of SARS-CoV-2 infection. As well, the possible role of PGs in the pathogenesis of SARS-CoV-2 infection is not well-defined. Thus, the objective of the present study is to review the potential role of PGs and NSAIDs in Covid-19 in a narrative review regarding the preponderance of assorted views.

Characterization of prostanoids response to Bordetella pertussis antigen BscF and Tdap in LPS-challenged monocytes

Prostanoids are potent inflammatory mediators that play a regulatory role in the innate immune activation of the adaptive immune response to determine the duration of protection against infection. We aim to quantify the modulation of prostanoids profiles in lipopolysaccharide (LPS)-stimulated THP-1 cells treated with the novel pertussis antigen BscF. We compared the effect with pertussis antigens present in the current Tdap vaccine to understand the immunomodulatory effect that might contribute to the diminished Tdap vaccine effectiveness. The inflammatory challenge with LPS induced a robust elevation of most prostanoid family members compared to the control treatment. Treatment with BscF and Tdap significantly reduced the LPS-stimulated elevation of prostaglandins (PGs) D2, E2, and F2α, as well as thromboxane (TX) A2 levels. An opposite trend was observed for PGI2, as both antigens accelerated the LPS-stimulated upregulation. Further, we quantified cyclooxygenases (COXs) that catalyze the biosynthesis of prostanoids and found that both antigens significantly reduced LPS-stimulated COX-1 and COX-2, demonstrating that the waning of acellular pertussis vaccines' protective immunity may be due to other downstream enzymes not related to COXs. Our present study validates the potential role of BscF as an adjuvant, resulting in the next-generation pertussis vaccine discovery.

The XPO1 Inhibitor KPT-8602 Ameliorates Parkinson's Disease by Inhibiting the NF-κB/NLRP3 Pathway

Exportin 1 (XPO1) is an important transport receptor that mediates the nuclear export of various proteins and RNA. KPT-8602 is a second-generation inhibitor of XPO1, demonstrating the lowest level of side effects, and is currently in clinical trials for the treatment of cancers. Previous studies suggest that several first-generation inhibitors of XPO1 demonstrate anti-inflammation activities, indicating the application of this drug in inflammation-related diseases. In this study, our results suggested the potent anti-inflammatory effect of KPT-8602 in vitro and in vivo. KPT-8602 inhibited the activation of the NF-κB pathway by blocking the phosphorylation and degradation of IκBα, and the priming of NLRP3. Importantly, the administration of KPT-8602 attenuated both lipopolysaccharide (LPS)-induced peripheral inflammation and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neuroinflammation in vivo. In addition, the tissue damage was also ameliorated by KPT-8602, indicating that KPT-8602 could be used as a novel potential therapeutic agent for the treatment of inflammasome-related diseases such as Parkinson’s disease, through the regulation of the NF-κB signaling pathway and the NLRP3 inflammasome.

Inflammatory mediators of cytokines and chemokines in sepsis: From bench to bedside

Background: Sepsis is a serious clinical condition characterized by damage to the immune system as a result of an uncontrolled response to infection. Septic patients show complications such as fever, cardiovascular shock, and/or systemic organ failure. Acute organ failure formed in sepsis mostly affects the respiratory and cardiovascular systems. In sepsis, responses including pro-inflammatory and anti-inflammatory processes in addition to the Toll-Like Receptor 4 (TLR4) signals leading to the release of inflammatory mediators have been suggested to be fundamental pathways in the pathophysiology of sepsis. Purpose: In this context, unregulated levels of sepsis-associated inflammatory mediators may increase the risk of mortality. In sepsis, infection-induced pathogens lead to a systemic inflammatory response. These systemic responses may contribute to septic shock and organ dysfunction. In the unfavorable clinical course of sepsis, an uncontrolled inflammatory response is observed. Accordingly, the mechanism of inflammatory mediators such as cytokines and chemokines in sepsis might increase. Neurotransmitters and gene regulators affect inflammatory mediators and control the inflammatory response. In this review, we aimed to show the new therapeutic targets in sepsis treatment with current studies. New clinical implications targeting inflammatory mediators in high mortality affected by the uncontrolled inflammatory response in sepsis can contribute to the understanding of the symptoms.

Discovery to Launch of Anti-allergy (Emadine; Patanol/Pataday/Pazeo) and Anti-glaucoma (Travatan; Simbrinza) Ocular Drugs, and Generation of Novel Pharmacological Tools Such as AL-8810

The eye and eyesight are exquistly designed and are precious, and yet we often take them for granted. Good vision is critical for our long-term survival and for humanity's enduring progress. Unfortunately, since ocular diseases do not culminate in life-and-death scenarios, awareness of the plight of millions of people suffering from such eye ailments is not publicized as other diseases. However, losing eyesight or falling victim to visual impairment is a frightening outlook for most people. Glaucoma, a collection of chronic optic neuropathies, of which the most prevalent form, primary open-angle glaucoma (POAG), is the second leading cause of irreversible blindness. POAG currently afflicts >70 million people worldwide and is an insidious, progressive, silent thief of sight that is asymptomatic. On the other hand, allergic conjunctivitis (AC), and the associated rhinitis ("hay-fever"), frequently victimizes a huge number of people worldwide, especially during seasonal changes. While not life-threatening, sufferers of AC soon learn the value of drugs to treat their signs and symptoms of AC as they desire rapid relief to overcome the ocular itching/pain, redness, and tearing AC causes. Herein, I will describe the collective efforts of many researchers whose industrious, diligent, and dedicated team work resulted in the discovery, biochemical/pharmacological characterization, development and eventual launch of drugs to treat AC (e.g., olopatadine [Patanol/Pataday/Pazeo] and emedastine [Emedine]), and for treating ocular hypertension and POAG (e.g., travoprost [Travatan ] and Simbrinza). This represents a personal perspective.