Isoforskolin and forskolin attenuate lipopolysaccharide-induced inflammation through TLR4/MyD88/NF-κB cascades in human mononuclear leukocytes

Forskolin treatment enhances muscle regeneration and shows therapeutic potential with limitations in Duchenne muscular dystrophy

BACKGROUND

Duchenne Muscular Dystrophy (DMD) is a progressive neuromuscular disorder characterized by impaired muscle repair. Forskolin (FSK), an adenylyl cyclase activator, has shown potential in enhancing muscle regeneration and limiting muscle stem cell senescence. This study aimed to evaluate the effects of FSK on muscle repair, fibrosis, inflammation, and long-term muscle function in DMD using a preclinical rat model.

METHODS

BaCl2-induced muscle injury was performed on 6-month-old DMD (R-DMDdel52) and wild-type (WT) rats. FSK was supplied via short-term and long-term administration. Muscle tissues were harvested 14 days post-injury for histological analysis, including hematoxylin and eosin and Sirius red staining. Immunofluorescence was used to assess fibroadipogenic progenitors (FAPs), regeneration, muscle stem cells, and macrophage phenotypes. Moreover, we performed a study by chronically administering FSK to DMD rats from 1 to 7 months of age, either intraperitoneally (IP) or subcutaneously (SC). Functional assessments included grip strength test, in vivo muscle force measurements, plethysmography and electrocardiograms. Post-sacrifice, Tibialis anterior, diaphragm and heart tissues were histologically analyzed, to evaluate muscle architecture, fibrosis, and histopathological indices.

RESULTS

FSK treatment significantly improved muscle histology and reduced fibrosis in both uninjured and injured DMD muscles by decreasing the number of FAPs. Long-term FSK treatment in the acute injury model enhanced muscle regeneration, increased MuSC proliferation, and reduced senescence. FSK also modulated inflammation by reducing pro-inflammatory macrophages and promoting a shift to a restorative phenotype. However, despite these histological improvements, FSK treatment from 1 to 7 months resulted in limited functional benefits and worsened ventricular histology in the heart.

CONCLUSIONS

FSK shows promising results in improving muscle regeneration and reducing fibrosis in DMD, but concerns remain regarding its limited chronic functional benefits and potential adverse effects on cardiac tissue. Our results highlight the need for optimized adenylyl cyclase activators for therapeutic use in DMD patients.

Flow Injection Analysis-Mass Spectrometry for the fast detection of frauds in Coleus forskohlii food supplements

Coleus forskohlii supplements (FKSs) are widely consumed for their obesity-preventing effects, mainly related to forskolin, its main bioactive compound. However, these supplements are susceptible to adulteration and various types of frauds have been described. Therefore, the development of rapid and sensitive methodologies is of great interest in order to determine the quality of these products. In this work, a new method by Flow Injection Analysis-Mass Spectrometry (FIA-MS) has been developed and validated for the detection of potential frauds in FKSs. A Box-Behnken experimental design was used for the optimization of MS parameters under both positive and negative polarity modes of the electrospray ionization source. The best results were obtained for positive polarity mode at 3000 V of capillary voltage, a flow rate of 12 L min-1 of drying gas, 300 °C of nebulization gas temperature, a pressure of 30 psi and a fragmentor voltage of 149 V, using 1 % of 1 mM sodium acetate in the carrier. When 22 FKSs were analysed by the optimised FIA-MS method, 45 % of the samples were found to be free of forskolin. There was also a high percentage (69%) of mismatches between the quantified forskolin content and that declared on the FSK labels. In general, results were comparable with those obtained by LC-MS. Thus, it has been proved that FIA-MS is a fast, cost-effective and simple tool to evaluate the authenticity of FKSs.

The therapeutic potential of Honeysuckle in cardiovascular disease: an anti-inflammatory intervention strategy

Honeysuckle is a conventional Chinese medicine with several therapeutic applications. With the advancement of modern scientific technologies, Honeysuckle's pharmacological effects and medicinal properties have been investigated more thoroughly. Studies demonstrate that the bioactive compounds in Honeysuckle possess anti-inflammatory effects via several mechanisms, protecting the cardiovascular system. This article provides a reference for the clinical use of Honeysuckle by reviewing research on the therapeutic impact of Honeysuckle and its active constituents on cardiovascular diseases, such as coronary atherosclerotic heart disease (CHD), myocardial ischemia-reperfusion (MI/R), acute myocardial infarction (AMI), hypertension, arrhythmia, and heart failure, through the inhibition of inflammatory responses.

The effects of Cordyceps polysaccharides on ischemic brain injury in rats via intervening with IL-23/IL-17 axis and the intestinal barrier

Cordyceps polysaccharide (CSP) has been shown to exhibit anti-inflammatory and antioxidant effects, with potential applications in ischemic stroke. This work is to explore the interventional potential of CSP in MCAO rats and the effects on the intestinal and cerebral IL-23/IL-17 axis. We conducted pharmacological experiments and mechanism exploration in MCAO rats. Our research showed that CSP improved the neurological function and cerebral pathological morphology, reduced cerebral infarction volume and water content in MCAO rats. We also found that CSP significantly decreased the IL-1β, TNF-α and IL-6 in the ischemic brain and enhanced the ability of MCAO rats to resist oxidative stress. Additionally, CSP improved intestinal barrier, inhibited the activation of the TLR4/Myd88/NF-κβ signaling pathway and IL-23/IL-17 axis. The study results demonstrated the effectiveness of CSP in interfering with MCAO rats. The mechanism appears to be related to protecting the intestinal barrier and inhibiting the IL-23/IL-17 axis.

From Molecular Mechanisms to Clinical Therapy: Understanding Sepsis-Induced Multiple Organ Dysfunction

Sepsis-induced multiple organ dysfunction arises from the highly complex pathophysiology encompassing the interplay of inflammation, oxidative stress, endothelial dysfunction, mitochondrial damage, cellular energy failure, and dysbiosis. Over the past decades, numerous studies have been dedicated to elucidating the underlying molecular mechanisms of sepsis in order to develop effective treatments. Current research underscores liver and cardiac dysfunction, along with acute lung and kidney injuries, as predominant causes of mortality in sepsis patients. This understanding of sepsis-induced organ failure unveils potential therapeutic targets for sepsis treatment. Various novel therapeutics, including melatonin, metformin, palmitoylethanolamide (PEA), certain herbal extracts, and gut microbiota modulators, have demonstrated efficacy in different sepsis models. In recent years, the research focus has shifted from anti-inflammatory and antioxidative agents to exploring the modulation of energy metabolism and gut microbiota in sepsis. These approaches have shown a significant impact in preventing multiple organ damage and mortality in various animal sepsis models but require further clinical investigation. The accumulation of this knowledge enriches our understanding of sepsis and is anticipated to facilitate the development of effective therapeutic strategies in the future.

Impact of seasonal variation on four labdane-type diterpenoids in Coleus forskholii Briq

The present study has been planned to evaluate the impact of seasonal variation in labdane-type diterpenoids namely isoforskolin, forskolin, 1,9-dideoxyforskolin and 1-deoxyforskolin in Coleus forskholii (roots). The plant samples were harvested in different seasons from our experimental field located at CSIR-NBRI garden, Lucknow (India) and metabolite contents were estimated through validated high performance thin layer chromatography (HPTLC) method. The HPTLC plate was developed in tertiary mobile phase of toluene-ethyl acetate-methanol (8.5-1-0.05 v/v) for separation of all the four metabolites. The metabolite content viz. isoforskolin, forskolin, 1,9-dideoxyforskolin and 1-deoxyforskolin varies from 0.0247% to 0.198%, 0.238 to 0.730%, 0.056 to 0.161% and 0.0401 to 0.332% on dry weight basis respectively. The maximum content of metabolites was recorded in winter season and was found optimum for harvesting of C. forskholii roots. Optimization of harvesting season for this industrially valuable medicinal plant will lead to sustainable sources of good quality raw material to herbal drug industry.

Forskolin rescues hypoxia-induced cognitive dysfunction in zebrafish with potential involvement of O-GlcNAc cycling regulation

Repeated sublethal hypoxia exposure induces brain inflammation and affects the initiation and progression of cognitive dysfunction. Experiments from the current study showed that hypoxic exposure downregulates PKA/CREB signaling, which is restored by forskolin (FSK), an adenylate cyclase activator, in both Neuro2a (N2a) cells and zebrafish brain. FSK significantly protected N2a cells from hypoxia-induced cell death and neurite shrinkage. Intraperitoneal administration of FSK for 5 days on zebrafish additionally led to significant recovery from hypoxia-induced social interaction impairment and learning and memory (L/M) deficit. FSK suppressed hypoxia-induced neuroinflammation, as indicated by the observed decrease in NF-κB activation and GFAP expression. We further investigated the potential effect of FSK on O-GlcNAcylation changes induced by hypoxia. Intriguingly FSK induced marked upregulation of the protein level of O-GlcNAc transferase catalyzing addition of the GlcNAc group to target proteins, accompanied by elevated O-GlcNAcylation of nucleocytoplasmic proteins. The hypoxia-induced O-GlcNAcylation decrease in the brain of zebrafish was considerably restored following FSK treatment. Based on the collective results, we propose that FSK rescues hypoxia-induced cognitive dysfunction, potentially through regulation of HBP/O-GlcNAc cycling.

Synergistic Enhancement of Isoforskolin and Dexamethasone Against Sepsis and Acute Lung Injury Mouse Models

BACKGROUND

Sepsis is initiated by the dysfunctional response of the host immune system to infection. Septic shock and acute lung injury (ALI) are the main etiology of death caused by sepsis. Glucocorticoids, which are commonly used in clinic to antagonize the inflammatory response of sepsis, may cause serious side effects. Isoforskolin (ISOF) from the plant Coleus forskohlii stimulates adenylyl cyclase, increases the cAMP level and inhibits inflammatory response. The aim of this study was to investigate the synergistic effect of ISOF with dexamethasone (DEX) to prevent and ameliorate septic inflammation.

METHODS

Lipopolysaccharide (LPS) of 30 and 5 mg/kg (iv.) was used to induce sepsis and ALI mice model respectively in vivo. BEAS-2B cells stimulated by LPS were applied as cell model in vitro. The cumulative survival of mice with LPS-induced sepsis and the histopathological changes of lungs in mice with acute lung injury were observed, and the secretion of pro-inflammatory cytokines was analyzed by ELISA. The expression of RGS2 in BEAS-2B cells was detected by immunoblotting assay and PCR.

RESULTS

In the sepsis mice model, ISOF (10 mg/kg) combined with DEX (10 mg/kg.) (ip.) pretreatment significantly increased mice survival rate from 33.3% to 58.3%, which was significantly higher than that of ISOF or DEX treated alone. In the ALI mice model, ISOF, DEX pretreatment alone and combined application attenuated pulmonary pathological changes in ALI mice. Furthermore, ISOF, DEX alone or combined administration decreased MPO, MDA, IL-6, and IL-8 levels, while significantly synergistic effects were observed in the combined treatment group compared with ISOF or DEX alone. In BEAS-2B cells, combined pretreatment with ISOF and DEX significantly decreased the expression of IL-8 and increased the expression of RGS2.

CONCLUSION

The results indicated that ISOF in combination with DEX synergistically improves survival rate and attenuates ALI in mice model through anti-inflammatory and antioxidant effects.

Modeling the Progression of Placental Transport from Early- to Late-Stage Pregnancy by Tuning Trophoblast Differentiation and Vascularization

The early-stage placental barrier is characterized by a lack of fetal circulation and by a thick trophoblastic barrier, whereas the later-stage placenta consists of vascularized chorionic villi encased in a thin, differentiated trophoblast layer, ideal for nutrient transport. In this work, predictive models of early- and late-stage placental transport are created using blastocyst-derived placental stem cells (PSCs) by modulating PSC differentiation and model vascularization. PSC differentiation results in a thinner, fused trophoblast layer, as well as an increase in human chorionic gonadotropin secretion, barrier permeability, and secretion of certain inflammatory cytokines, which are consistent with in vivo findings. Further, gene expression confirms this shift toward a differentiated trophoblast subtype. Vascularization results in a molecule type- and size-dependent change in dextran and insulin permeability. These results demonstrate that trophoblast differentiation and vascularization have critical effects on placental barrier permeability and that this model can be used as a predictive measure to assess fetal toxicity of xenobiotic substances at different stages of pregnancy.

Polyphenols, flavonoids and inflammasomes: the role of cigarette smoke in COPD

COPD is predicted to become the third leading cause of morbidity and mortality worldwide by 2030. Cigarette smoking (active or passive) is one of its chief causes, with about 20% of cigarette smokers developing COPD from cigarette smoke (CS)-induced irreversible damage and sustained inflammation of the airway epithelium. Inflammasome activation leads to the cleavage of pro-interleukin (IL)-1β and pro-IL-18, along with the release of pro-inflammatory cytokines via gasdermin D N-terminal fragment membrane pores, which further triggers acute phase pro-inflammatory responses and concurrent pyroptosis. There is currently intense interest in the role of nucleotide-binding oligomerisation domain-like receptor family, pyrin domain containing protein-3 inflammasomes in chronic inflammatory lung diseases such as COPD and their potential for therapeutic targeting. Phytochemicals including polyphenols and flavonoids have phyto-medicinal benefits in CS-COPD. Here, we review published articles from the last decade regarding the known associations between inflammasome-mediated responses and ameliorations in pre-clinical manifestations of CS-COPD via polyphenol and flavonoid treatment, with a focus on the underlying mechanistic insights. This article will potentially assist the development of drugs for the prevention and therapy of COPD, particularly in cigarette smokers.

This review compiles current investigations into the role of polyphenols/flavonoids in the alleviation of cigarette smoke-induced inflammasome; notably it provides a promising hit for rectifying the treatment of COPD.https://bit.ly/36OcUO9

Butyrate in combination with forskolin alleviates necrotic enteritis, increases feed efficiency, and improves carcass composition of broilers

BACKGROUND

The emergence of antimicrobial resistance has necessitated the development of effective alternatives to antibiotics for livestock and poultry production. This study investigated a possible synergy between butyrate and forskolin (a natural labdane diterpene) in enhancing innate host defense, barrier function, disease resistance, growth performance, and meat quality of broilers.

METHODS

The expressions of representative genes involved in host defense (AvBD9 and AvBD10), barrier function (MUC2, CLDN1, and TJP1), and inflammation (IL-1β) were measured in chicken HD11 macrophages in response to butyrate and forskolin in the presence or absence of bacterial lipopolysaccharides (LPS). Intestinal lesions and the Clostridium perfringens titers were also assessed in C. perfringens-challenged chickens fed butyrate and forskolin-containing Coleus forskohlii (CF) extract individually or in combination. Furthermore, growth performance and carcass characteristics were evaluated in broilers supplemented with butyrate and the CF extract for 42 d.

RESULTS

Butyrate and forskolin synergistically induced the expressions of AvBD9, AvBD10, and MUC2 in chicken HD11 cells (P < 0.05) and the synergy was maintained in the presence of LPS. Butyrate and forskolin also suppressed LPS-induced IL-1β gene expression in HD11 cells in a synergistic manner (P < 0.05). The two compounds significantly reduced the intestinal lesions of C. perfringens-challenged chickens when combined (P < 0.05), but not individually. Furthermore, butyrate in combination with forskolin-containing CF extract had no influence on weight gain, but significantly reduced feed intake (P < 0.05) with a strong tendency to improve feed efficiency (P = 0.07) in a 42-d feeding trial. Desirably, the butyrate/forskolin combination significantly decreased abdominal fat deposition (P = 0.01) with no impact on the carcass yield, breast meat color, drip loss, or pH of d-42 broilers.

CONCLUSIONS

Butyrate and forskolin has potential to be developed as novel antibiotic alternatives to improve disease resistance, feed efficiency, and carcass composition of broilers.

Qingwenzhike Prescription Alleviates Acute Lung Injury Induced by LPS via Inhibiting TLR4/NF-kB Pathway and NLRP3 Inflammasome Activation

Background: Acute lung injury (ALI) is characterized by dysfunction of the alveolar epithelial membrane caused by acute inflammation and tissue injury. Qingwenzhike (QWZK) prescription has been demonstrated to be effective against respiratory viral infections in clinical practices, including coronavirus disease 2019 (COVID-19) infection. So far, the chemical compositions, protective effects on ALI, and possible anti-inflammatory mechanisms remain unknown.

Methods: In this study, the compositions of QWZK were determined via the linear ion trap/electrostatic field orbital trap tandem high-resolution mass spectrometry (UHPLC-LTQ-Orbitrap MS). To test the protective effects of QWZK on ALI, an ALI model induced by lipopolysaccharide (LPS) in rats was used. The effects of QWZK on the LPS-induced ALI were evaluated by pathological changes and the number and classification of white blood cell (WBC) in bronchoalveolar lavage fluid (BALF). To investigate the possible underlying mechanisms, the contents of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein (MCP-1), interleukin-1β (IL-1β), interleukin-18 (IL-18), and immunoregulatory-related factors interferon-γ (IFN-γ) were detected by ELISA. Furthermore, the expression of Toll-like receptor 4 (TLR4), p-IKKα/β, IKKα, IKKβ, p-IκBα, IκBα, p-NF-κB, nuclear factor-κB (NF-κB), NOD-like receptor family pyrin domain containing 3 (NLRP3), cleaved caspase-1, pro-caspase-1, apoptosis-associated speck-like protein containing CARD (ASC), and β-actin were tested by Western blot.

Results: A total of 99 compounds were identified in QWZK, including 33 flavonoids, 23 phenolic acids, 3 alkaloids, 3 coumarins, 20 triterpenoids, 5 anthraquinones, and 12 others. ALI rats induced by LPS exhibited significant increase in neutrophile, significant decrease in lymphocyte, and evidently thicker alveolar wall than control animals. QWZK reversed the changes in WBC count and alveolar wall to normal level on the model of ALI induced by LPS. ELISA results revealed that QWZK significantly reduced the overexpression of proinflammatory factors IL-6, TNF-α, MCP-1, IL-1β, IL-18, and IFN-γ induced by LPS. Western blot results demonstrated that QWZK significantly downregulated the overexpression of TLR4, p-IKKα/β, p-IκBα, p-NF-κB, NLRP3, cleaved caspase-1, and ASC induced by LPS, which suggested that QWZK inhibited TLR4/NF-κB signaling pathway and NLRP3 inflammasomes.

Conclusions: The chemical compositions of QWZK were first identified. It was demonstrated that QWZK showed protective effects on ALI induced by LPS. The possible underlying mechanisms of QWZK on ALI induced by LPS was via inhibiting TLR4/NF-kB signaling pathway and NLRP3 inflammasome activation. This work suggested that QWZK is a potential therapeutic candidate for the treatments of ALI and pulmonary inflammation.

Isoforskolin, an adenylyl cyclase activator, attenuates cigarette smoke-induced COPD in rats

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by limited airflow due to pulmonary and alveolar abnormalities from exposure to cigarette smoke (CS). Current therapeutic drugs are limited and the development of novel treatments to prevent disease progression is challenging. Isoforskolin (ISOF) from the plant Coleus forskohlii is an effective activator of adenylyl cyclase (AC) isoforms. Previously we found ISOF could attenuate acute lung injury in animal models, while the effect of ISOF on COPD has not been elucidated.

PURPOSE

In this study, we aimed to evaluate the efficacy of ISOF on COPD and reveal its potential mechanisms.

METHODS

A rat model of COPD was established by long-term exposure to CS, then the rats were orally administered with ISOF (0.5, 1 and 2 mg/kg). The pulmonary function, lung morphology, inflammatory cells and cytokines in serum or bronchoalveolar lavage fluid (BALF) were evaluated. Transcriptomics, proteomics and network pharmacology analysis were utilized to identify potential mechanisms of ISOF. Droplet digital PCR was used to detect the mRNA expression of AC1-10 in donor lung tissues. AC activation was determined in recombinant human embryonic kidney 293 (HEK293) cells stably expressing human AC isoforms. In addition, ISOF caused trachea relaxation ex vivo were assessed in isolated trachea rings from guinea pigs.

RESULTS

ISOF significantly ameliorated pathological damage of lung tissue and improved pulmonary function in COPD rats. ISOF treatment decreased the number of inflammatory cells in peripheral blood, and also the levels of pro-inflammatory cytokines in serum and BALF. Consistent with omics-based analyses, ISOF markedly downregulated the mTOR level in lung tissue. Flow cytometry analysis revealed that ISOF treatment reduced the ratio of Th17/Treg cells in peripheral blood. Furthermore, the expression levels of AC1 and AC2 are relatively higher than other AC isoforms in normal lung tissues, and ISOF could potently activate AC1 and AC2 in vitro and significantly relax isolated guinea pig trachea.

CONCLUSION

Collectively, our studies suggest that ISOF exerts its anti-COPD effect by improving lung function, anti-inflammation and trachea relaxation, which may be related to AC activation, mTOR signaling and Th17/Treg balance.

Promising drug repurposing approach targeted for cytokine storm implicated in SARS-CoV-2 complications

A global threat has emerged in 2019 due to the rapid spread of Coronavirus disease (COVID-19). As of January 2021, the number of cases worldwide reached 103 million cases and 2.22 million deaths which were confirmed as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This global pandemic galvanized the scientific community to study the causative virus (SARS-CoV2) pathogenesis, transmission, and clinical symptoms. Remarkably, the most common complication associated with this disease is the cytokine storm which is responsible for COVID-19 mortality. Thus, targeting the cytokine storm with new medications is needed to hamper COVID-19 complications where the most prominent strategy for the treatment is drug repurposing. Through this strategy, several steps are skipped especially those required for testing drug safety and thus may help in reducing the dissemination of this pandemic. Accordingly, the aim of this review is to outline the pathogenesis, clinical features, and immune complications of SARS-CoV2 in addition to suggesting several repurposed drugs with their plausible mechanism of action for possible management of severe COVID-19 cases.

Isoforskolin Alleviates AECOPD by Improving Pulmonary Function and Attenuating Inflammation Which Involves Downregulation of Th17/IL-17A and NF-κB/NLRP3

Chronic obstructive pulmonary disease (COPD), a major cause of morbidity and mortality worldwide, is widely considered to be related to cigarette smoke (CS), and viral infections trigger acute exacerbation of COPD (AECOPD). Isoforskolin (ISOF) is a bioactive component from the plant Coleus forskohlii, native to Yunnan in China. It has been demonstrated that ISOF has anti-inflammatory effect on acute lung injury animal models. In the present study, we investigated the efficacy and mechanism of ISOF for the prevention and treatment of AECOPD. Mice were exposed to CS for 18 weeks and then infected with influenza virus A/Puerto Rico/8/34 (H1N1). ISOF (0.5, 2 mg/kg) was intragastrically administered once a day after 8 weeks of exposure to cigarette smoke when the body weight and lung function of model mice declined significantly. The viral load, pulmonary function, lung morphology, Th17 cells, and inflammatory cytokines in lung tissues were evaluated. The expression of nuclear factor κB (NF-κB) and NOD-like receptor pyrin domain–containing protein 3 (NLRP3) inflammasome pathways were detected. The results showed that ISOF treatment reduced the viral load in the lung homogenate, decreased the lung index of model mice, and lung pathological injuries were alleviated. ISOF also improved the pulmonary function with increased FEV0.1/FVC and decreased Rn and Rrs. The levels of inflammatory mediators (TNF-α, IL-1β, IL-6, IL-17A, MCP-1, MIG, IP-10, and CRP) in the lung homogenate were reduced after ISOF treatment. ISOF decreased the proportion of Th17 cells in the lung tissues by the flow cytometry test, and the protein expression levels of RORγt and p-STAT3 were also decreased. Furthermore, ISOF significantly inhibited the activation of NF-κB signaling and NLRP3 inflammasome in the lung tissues of model mice. In conclusion, ISOF alleviates AECOPD by improving pulmonary function and attenuating inflammation via the downregulation of proinflammatory cytokines, Th17/IL-17 A, and NF-κB/NLRP3 pathways.

Rotundic acid reduces LPS-induced acute lung injury in vitro and in vivo through regulating TLR4 dimer

Acute lung injury (ALI) is a serious clinical disease. Rotundic acid (RA), a natural ingredient isolated from Ilex rotunda Thunb, exhibits multiple pharmacological activities. However, RA's therapeutic effect and mechanism on ALI remain to be elucidated. The present study aimed to further clarify its regulating effects on inflammation in vitro and in vivo. Our results indicated that RA significantly inhibited the overproduction of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). RA decreased ROS production and calcium influx. In addition, RA inhibited the activation of PI3K, MAPK, and NF-κB pathways and enhanced the activity of nuclear factor E2-related factor 2 (Nrf2) signaling. The cellular thermal shift assay and docking results indicated that RA bind to TLR4 to block TLR4 dimerization. Furthermore, RA pretreatment effectively inhibited ear edema induced by xylene and LPS-induced endotoxin death and had a protective effect on LPS-induced ALI. Our findings collectively indicated that RA has anti-inflammatory effects, which may serve as a potential therapeutic option for pulmonary inflammation.

New Insights into Pathomechanisms and Treatment Possibilities for Lung Silicosis

Inhalation of silica particles is an environmental and occupational cause of silicosis, a type of pneumoconiosis. Development of the lung silicosis is a unique process in which the vicious cycle of ingestion of inhaled silica particles by alveolar macrophages and their release triggers inflammation, generation of nodular lesions, and irreversible fibrosis. The pathophysiology of silicosis is complex, and interactions between the pathomechanisms have not been completely understood. However, elucidation of silica-induced inflammation cascades and inflammation-fibrosis relations has uncovered several novel possibilities of therapeutic targeting. This article reviews new information on the pathophysiology of silicosis and points out several promising treatment approaches targeting silicosis-related pathways.

Characterization of Burn Eschar Pericytes

Pericytes are cells that reside adjacent to microvasculature and regulate vascular function. Pericytes gained great interest in the field of wound healing and regenerative medicine due to their multipotential fate and ability to enhance angiogenesis. In burn wounds, scarring and scar contractures are the major pathologic feature and cause loss of mobility. The present study investigated the influence of burn wound environment on pericytes during wound healing. Pericytes isolated from normal skin and tangentially excised burn eschar tissues were analyzed for differences in gene and protein expression using RNA-seq., immunocytochemistry, and ELISA analyses. RNA-seq identified 443 differentially expressed genes between normal- and burn eschar-derived pericytes. Whereas, comparing normal skin pericytes to normal skin fibroblasts identified 1021 distinct genes and comparing burn eschar pericytes to normal skin fibroblasts identified 2449 differential genes. Altogether, forkhead box E1 (FOXE1), a transcription factor, was identified as a unique marker for skin pericytes. Interestingly, FOXE1 levels were significantly elevated in burn eschar pericytes compared to normal. Additionally, burn wound pericytes showed increased expression of profibrotic genes periostin, fibronectin, and endosialin and a gain in contractile function, suggesting a contribution to scarring and fibrosis. Our findings suggest that the burn wound environment promotes pericytes to differentiate into a myofibroblast-like phenotype promoting scar formation and fibrosis.

The Role of Serotonin in Concanavalin A-Induced Liver Injury in Mice

Serotonin is involved in the pathological processes of several liver diseases via the regulation of inflammatory response and oxidative stress. We aimed to investigate the role of serotonin in Concanavalin A- (Con A-) induced acute liver injury (ALI). ALI was induced in C57B/6 wild-type (WT) mice and tryptophan hydroxylase 1 (TPH1) knockout mice through tail vein injection of Con A (15 mg/kg body weight). Another group of TPH1 knockout ALI mice was supplied with 5-hydroxytryptophan (5-HTP) in advance to recover serotonin. The blood and liver tissues of mice were collected in all groups. Markedly increased serum levels of serotonin were identified after the injection of Con A. Increased serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and stronger hepatic tissue pathology were detected, suggesting that serotonin could mediate Con A-induced liver damage. Serotonin significantly facilitated the release of serum and intrahepatic inflammatory cytokines, including interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-17A (IL-17A), interferon-gamma (IFN-γ), and tumor necrosis-alpha (TNF-α), after the administration of Con A. In addition, serotonin significantly increased the intrahepatic levels of oxidative stress markers malonaldehyde (MDA), myeloperoxidase (MPO), and nitric oxide (NO) and decreased antioxidant stress indicator glutathione (GSH) in Con A-treated mice. Additionally, serotonin promoted hepatocyte apoptosis and autophagy based on B-cell lymphoma-2 (Bcl-2), Bcl-2-asociated X protein (Bax), and Beclin-1 levels and TUNEL staining. More importantly, serotonin activated nuclear factor kappa B (NF-κB) and upregulated the hepatic expressions of high mobility group protein B1 (HMGB1), toll-like receptor-4 (TLR4), and downstream molecules in Con A-mediated liver injury. Serotonin 2A receptor was upregulated in liver tissue after Con A injection, and serotonin 2A receptor antagonist Ketanserin protected against Con A-induced hepatitis. These results indicated that serotonin has the potential to aggravate Con A-induced ALI via the promotion of inflammatory response, oxidative stress injury, and hepatocyte apoptosis and the activation of hepatic HMGB1-TLR signaling pathway and serotonin 2A receptor.

The Role of Serotonin in Concanavalin A-Induced Liver Injury in Mice

Serotonin is involved in the pathological processes of several liver diseases via the regulation of inflammatory response and oxidative stress. We aimed to investigate the role of serotonin in Concanavalin A- (Con A-) induced acute liver injury (ALI). ALI was induced in C57B/6 wild-type (WT) mice and tryptophan hydroxylase 1 (TPH1) knockout mice through tail vein injection of Con A (15 mg/kg body weight). Another group of TPH1 knockout ALI mice was supplied with 5-hydroxytryptophan (5-HTP) in advance to recover serotonin. The blood and liver tissues of mice were collected in all groups. Markedly increased serum levels of serotonin were identified after the injection of Con A. Increased serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and stronger hepatic tissue pathology were detected, suggesting that serotonin could mediate Con A-induced liver damage. Serotonin significantly facilitated the release of serum and intrahepatic inflammatory cytokines, including interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-17A (IL-17A), interferon-gamma (IFN-γ), and tumor necrosis-alpha (TNF-α), after the administration of Con A. In addition, serotonin significantly increased the intrahepatic levels of oxidative stress markers malonaldehyde (MDA), myeloperoxidase (MPO), and nitric oxide (NO) and decreased antioxidant stress indicator glutathione (GSH) in Con A-treated mice. Additionally, serotonin promoted hepatocyte apoptosis and autophagy based on B-cell lymphoma-2 (Bcl-2), Bcl-2-asociated X protein (Bax), and Beclin-1 levels and TUNEL staining. More importantly, serotonin activated nuclear factor kappa B (NF-κB) and upregulated the hepatic expressions of high mobility group protein B1 (HMGB1), toll-like receptor-4 (TLR4), and downstream molecules in Con A-mediated liver injury. Serotonin 2A receptor was upregulated in liver tissue after Con A injection, and serotonin 2A receptor antagonist Ketanserin protected against Con A-induced hepatitis. These results indicated that serotonin has the potential to aggravate Con A-induced ALI via the promotion of inflammatory response, oxidative stress injury, and hepatocyte apoptosis and the activation of hepatic HMGB1-TLR signaling pathway and serotonin 2A receptor.

Forskolin attenuates the NLRP3 inflammasome activation and IL-1β secretion in human macrophages

BACKGROUND

The treatment of nucleotide-binding domain and leucine-rich repeat containing family, pyrin domain containing 3 (NLRP3) inflammasome-mediated pediatric inflammatory diseases is challenging. Here we studied whether cyclic adenosine monophosphate (cAMP) elevator forskolin could attenuate the nigericin-induced NLRP3-inflammasome activation and interleukin-1β (IL-1β) secretion in human macrophages.

METHODS

The proteins and messenger RNA (mRNA) levels of inflammasome structural proteins and proinflammatory cytokines were measured in forskolin-stimulated nigericin-activated human THP-1 macrophages and primary macrophages.

RESULTS

Activation of THP-1 macrophages with nigericin increased the mRNA expression of NLRP3, IL-1β, and caspase-1 (P < 0.01). Forskolin stimulation had no effect on the mRNA expression of NLRP3, caspase-1, or IL-1β in nigericin-activated cells (P > 0.05), while their protein levels were significantly decreased (P < 0.05). Forskolin-mediated increase in cytoplasmic cAMP in non-activated cells was attenuated in nigericin-activated macrophages (P < 0.05). Basal IL-1β secretion increased from 584 to 2696 pg/mL (P < 0.01) in nigericin-activated macrophages; forskolin dose-dependently reduced the nigericin-induced secretion of mature IL-1β (P < 0.01). Forskolin also inhibited the IL-1β secretion from activated human primary macrophages.

CONCLUSIONS

Forskolin inhibits the NLRP3 inflammasome activation and the secretion of mature IL-1β, in human macrophages. Forskolin and other cAMP elevator drugs could represent a novel approach for treatment of diseases associated with excessive inflammasome activation, like pediatric inflammatory diseases.

Rapid Screening of Forskolin-Type Diterpenoids of Blumea aromatica DC Using Ultra-High-Performance Liquid Chromatography Tandem Quadrupole Time-of-Flight Mass Spectrometry Based on the Mass Defect Filtering Approach

The discovery of new active compounds of natural products tends to be increasingly more challenging due to chemical complexity and unpredictable matrices. Forskolin is an active natural labdane-type diterpenoid ingredient widely used worldwide for the treatment of glaucoma, heart failure, hypertension, diabetes, and asthma, and is expected to be a promising anticancer, anti-inflammation, and anti-HIV agent. In recent years, demand for forskolin in the medicine market has increased dramatically. However, natural forskolin originates exclusively from traditional Indian herb medicine Coleus forskohlii (Willd.) Briq. In a previous study, we isolated a series of diterpenoids including an 8,13-epoxy-14ene labdane carbon skeleton from Blumea aromatica DC. In order to identify alternative plant resources, a novel and effective strategy was proposed for the screening of potential forskolin-type diterpenoids (FSKD) compounds obtained from B. aromatica, using the mass defect filtering (MDF) strategy via ultra-high-performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (UHPLC-QTOF/MS) approach. Within a narrow, well-defined mass defect range, the strategy developed could significantly improve the detection efficiency of selected FSKD compounds by filtering out certain major or moderate interference compounds. Additionally, the MS/MS cleavage behavior and the characteristic diagnostic ions of the FSKD compounds were proposed to be used in aiding structural identification of the filtration compounds. As a result, a total of 38 FSKD of B. aromatica were filtered out and tentatively identified. To the best of our knowledge, it was the first time that these forskolin-type diterpenoids were identified in B. aromatica, which significantly expands our understanding of the chemical constituents of Blumea species, and allows B. aromatica to be used as a potential alternative plant resource that contains these forskolin-type active compounds. The strategy proposed was proven efficient and reliable for the discovery of novel compounds of herbal extracts.

Isoforskolin and forskolin attenuate lipopolysaccharide-induced inflammation through TLR4/MyD88/NF-κB cascades in human mononuclear leukocytes

The principal active component of isoforskolin (ISOF) is from the plant Coleus forskohlii, native to China, which has attracted much attention for its biological effects. We hypothesize that ISOF and forskolin (FSK) pretreatment attenuates inflammation induced by lipopolysaccharide (LPS) related to toll‐like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and nuclear factor kappa B (NF‐κB) signaling. Mononuclear leukocytes (MLs) from healthy donors' blood samples were separated by using density gradient centrifugation. Protein levels of TLR4, MyD88, and NF‐κB were detected using western blot and inflammatory cytokines interleukin (IL) 1β, IL‐2, IL‐6, IL‐21, IL‐23, tumor necrosis factor (TNF) α, and TNF‐β were tested by enzyme‐linked immunosorbent assay and Quantibody array in MLs. Our results showed that LPS augmented the protein levels of TLR4, MyD88, and NF‐κB in MLs and the production of IL‐1β, IL‐2, IL‐6, IL‐21, IL‐23, TNF‐α, and TNF‐β in supernatants of MLs. Despite treatment with ISOF and FSK prior to LPS, the protein levels of TLR4, MyD88, NF‐κB, IL‐1β, IL‐2, IL‐6, IL‐21, IL‐23, TNF‐α, and TNF‐β in MLs were apparently decreased. roflumilast (RF) and dexamethasone (DM) had a similar effect on MLs with ISOF and FSK. Our results, for the first time, have shown that ISOF and FSK attenuate inflammation in MLs induced by LPS through down‐regulating protein levels of IL‐1β and TNF‐α, in which TLR4/MyD88/NF‐κB signal pathway could be involved.