Narciclasine improves outcome in sepsis among neonatal rats via inhibition of calprotectin and alleviating inflammatory responses

Anti-inflammatory Principles of the Plant Family Amaryllidaceae

There is considerable interest in the utilisation of plants against inflammation. Over 50 species of the plant family Amaryllidaceae are known for such usage in traditional medicine. This review was undertaken to identify the chemical principles responsible for these anti-inflammatory effects. It describes the findings from in vitro, in vivo and in silico studies, as well as the probes made on the mechanisms of action. The literature search returned over 600 hits, of which around 130 were chosen for their relevance to the text. Over 140 compounds have thus far been screened for anti-inflammatory effects. These were mostly isoquinoline alkaloids but also included other classes of secondary metabolites such as chromones, flavonoids and triterpenoids. In vitro studies were carried out in mononuclear cells such as lymphocytes, monocytes, neutrophils and macrophages, against which no serious side effects were observed. The constituents were also effective against inflammation induced by physical and chemical stimuli in a variety of murine test subjects. Chief among the compounds were the isoquinoline alkaloids lycorine and narciclasine, which displayed potent effects against pain, swelling, asthma and arthritis, amongst others. From a mechanistic perspective, several of the compounds were shown to mediate in inflammatory pathways, notably via the modulation of both pro-inflammatory (such as NF-κB, TNF-α and IL-1) and anti-inflammatory (such as IL-10 and TGF-β) factors. Useful insights also emerged from active-site docking studies of some of the compounds. The Amaryllidaceae affords a rich and diverse platform for the discovery of potential anti-inflammatory drugs.

Effectiveness of Narciclasine in Suppressing the Inflammatory Response in Sepsis: Molecular Docking and In Silico Studies

Narciclasine is an alkaloid belonging to the Amaryllidaceae family which has been reported to have many beneficial properties. Especially its anticancer properties have been widely reported. Here, we have focused on its potential use in suppressing the inflammatory response in sepsis using in silico methods. Lipopolysaccharide (LPS) is an endotoxin which is present in the outer membrane of gram-negative bacteria and is a crucial player in the pathogenesis of gram-negative sepsis. Activation of toll-like receptor 4 (TLR4) signaling by LPS is an important event in the pathogenesis of gram-negative sepsis. This initiates a downstream signaling pathway comprising of several adaptor proteins such as toll/interleukin-1 receptor domain-containing adapter protein (TIRAP), myeloid differentiation primary response protein 88 (MyD88), interleukin-1 receptor-associated kinase (IRAK)-1, IRAK-4, interferon regulatory factor 3 (IRF-3), tumor necrosis factor receptor-associated factor 6 (TRAF-6) leading to nuclear factor kappa B (NF-κβ) activation resulting in elevated production of inflammatory cytokines such as tumor necrosis factor alpha (TNF-α) and interleukin (IL)-6. S100 calcium binding proteins A8/A9 (S100A8/A9) have been found to be an agonist of TLR4, and it amplifies the inflammatory response in sepsis. Molecular docking studies of narciclasine with target proteins associated with the LPS-TLR4 pathway showed that it has good binding affinity and stable interactions with the targets studied. Molecular dynamics (MD) simulation studies over 100 ns showed that most of the ligand-target complexes were stable. The structures of all the targets except TRAF-6 were retrieved from the Protein Data Bank (PDB) database. Homology modeling was done to predict the 3-dimensional structure of TRAF-6. MD simulation of narciclasine-TRAF-6 complex showed that the structure is stable. Metapocket was used for active site prediction in the target proteins. Toxicity analysis by admetSAR revealed that narciclasine was readily biodegradable and exhibited minimum toxicity. These results indicate that narciclasine has effective anti-inflammatory properties which could be useful in suppressing the inflammatory response in sepsis.

The RhoA-ROCK1/ROCK2 Pathway Exacerbates Inflammatory Signaling in Immortalized and Primary Microglia

Neuroinflammation is a unifying factor among all acute central nervous system (CNS) injuries and chronic neurodegenerative disorders. Here, we used immortalized microglial (IMG) cells and primary microglia (PMg) to understand the roles of the GTPase Ras homolog gene family member A (RhoA) and its downstream targets Rho-associated coiled-coil-containing protein kinases 1 and 2 (ROCK1 and ROCK2) in neuroinflammation. We used a pan-kinase inhibitor (Y27632) and a ROCK1- and ROCK2-specific inhibitor (RKI1447) to mitigate a lipopolysaccharide (LPS) challenge. In both the IMG cells and PMg, each drug significantly inhibited pro-inflammatory protein production detected in media (TNF-α, IL-6, KC/GRO, and IL-12p70). In the IMG cells, this resulted from the inhibition of NF-κB nuclear translocation and the blocking of neuroinflammatory gene transcription (iNOS, TNF-α, and IL-6). Additionally, we demonstrated the ability of both compounds to block the dephosphorylation and activation of cofilin. In the IMG cells, RhoA activation with Nogo-P4 or narciclasine (Narc) exacerbated the inflammatory response to the LPS challenge. We utilized a siRNA approach to differentiate ROCK1 and ROCK2 activity during the LPS challenges and showed that the blockade of both proteins may mediate the anti-inflammatory effects of Y27632 and RKI1447. Using previously published data, we show that genes in the RhoA/ROCK signaling cascade are highly upregulated in the neurodegenerative microglia (MGnD) from APP/PS-1 transgenic Alzheimer's disease (AD) mice. In addition to illuminating the specific roles of RhoA/ROCK signaling in neuroinflammation, we demonstrate the utility of using IMG cells as a model for primary microglia in cellular studies.

Repositioning linifanib as a potent anti-necroptosis agent for sepsis

Sepsis is a systemic inflammatory syndrome (SIRS) caused by acute microbial infection, and it has an extremely high mortality rate. Tumor necrosis factor-α (TNF-α)-induced necroptosis contributes to the pathophysiology of sepsis, so inhibiting necroptosis might be expected to improve clinical outcomes in septic patients. Here we predicted candidate drugs for treating sepsis in silico by combining genes differentially expressed in septic patients and controls combined with interrogation of the Library of Integrated Network-based Cellular Signatures (LINCS) L1000 perturbation database. Sixteen candidate drugs were screened out through bioinformatics analysis, and the top candidate linifanib was validated in cellular and mouse models of TNF-α-induced necroptosis. Cell viability was measured using a luminescent ATP assay, while the effects of linifanib on necroptosis were investigated by western blotting, immunoprecipitation, and RIPK1 kinase assays. Linifanib effectively protected cells from necroptosis and rescued SIRS mice from TNF-α-induced shock and death. In vitro, linifanib directly suppressed RIPK1 kinase activity. In vivo, linifanib effectively reduced overexpressed IL-6, a marker of sepsis severity, in the lungs of SIRS mice. Our preclinical evidence using an integrated in silico and experimental drug repositioning approach supports the potential clinical utility of linifanib in septic patients. Further clinical validation is now warranted.

Glimpses from My Academic Journey : Based on the 15th Dr. K. C. Chaudhuri Lifetime Achievement Award Oration Delivered on 9th October 2022

This article is based on the contents of 'Dr. K. C. Chaudhuri Lifetime Achievement Award Oration' delivered on the Indian Journal of Pediatrics Annual Day 2022. The author shares glimpses of his academic journey from a remote village to a central Institute. This includes his career as a medical teacher and developing the Department of Neonatology at JIPMER, Pondicherry. This article is primarily focused on some of the significant research conducted during his tenure, like perinatal asphyxia, therapeutic hypothermia, neonatal sepsis, intrauterine growth restriction, and human milk banking.

Plants' bioactive secondary metabolites in the management of sepsis: Recent findings on their mechanism of action

Sepsis is a severe inflammatory response to systemic infection and is a threatening cause of death in intensive care units. In recent years, a number of studies have been conducted on the protective effect of natural products against sepsis-induced organ injury. However, a comprehensive review of these studies indicating the mechanisms of action of the bioactive compounds is still lacking. In this context, this review aimed to provide an updated analysis of the mechanism of action of plants' secondary metabolites in the management of sepsis. Scopus, Science Direct, Google Scholar, and PubMed were searched from inception to July 2022. A variety of secondary metabolites were found to be effective in sepsis management including allicin, aloin, cepharanthine, chrysin, curcumin, cyanidin, gallic acid, gingerol, ginsenoside, glycyrrhizin, hesperidin, kaempferol, narciclasine, naringenin, naringin, piperine, quercetin, resveratrol, rosmarinic acid, shogaol, silymarin, sulforaphane, thymoquinone, umbelliferone, and zingerone. The protective effects exerted by these compounds can be ascribed to their antioxidant properties as well as induction of endogenous antioxidant mechanisms, and also via the downregulation of inflammatory response and reduction of biochemical and inflammatory markers of sepsis. These findings suggest that these secondary metabolites could be of potential therapeutic value in the management of sepsis, but human studies must be performed to provide strength to their potential clinical relevance in sepsis-related morbidity and mortality reduction.

Inflammatory markers S100A8/A9 and metabolic alteration for evaluating signs of early phase toxicity of anticancer agent treatment

Anticancer agents can cause various side effects, including tissue damages/inflammatory reactions. Drug-responsive biomarkers are essential for evaluating drug toxicity in disease processes. S100 calcium-binding proteins A8/A9 (S100A8/A9) are highly expressed in neutrophils and monocytes/macrophages accumulated at inflammatory sites and are known to be related to tissue damage/inflammation; however, their response to drug toxicity has not been reported. Herein, we investigated the effects of anticancer agents (doxorubicin, cisplatin, and docetaxel) on S100A8/A9 gene expression profiles in four representative tissues (heart, kidney, liver, and lung) in normal C57BL/6J mice. Both S100A8/A9 expression was transiently or time-dependently elevated in four tissues within 48 h after dosing of the three anticancer agents under toxicity-inducing conditions. S100A8/A9 patterns differed among agents and tissues. This result suggests that S100A8/A9 is useful for evaluating anticancer agent-induced tissue damage. Metabolomic analysis revealed that some metabolites showed temporal patterns similar to that of S100A8/A9 expression. The amounts of fumarate (doxorubicin-treated heart), tyrosine (cisplatin-treated kidney), acetylcarnosine (doxorubicin-treated liver), and 2-phosphoglycerate (docetaxel-treated lung) showed similar patterns to that of S100A8/A9 expression. Although these metabolites showed different behaviors between tissues and serum, they may be useful marker candidates for evaluating anticancer agent-induced tissue damage at an earlier stage after dosing.

Amaryllidaceae Alkaloids Decrease the Proliferation, Invasion, and Secretion of Clinically Relevant Cytokines by Cultured Human Colon Cancer Cells

Alkaloids isolated from members of the Amaryllidaceae plant family are promising anticancer agents. The purpose of the current study was to determine if the isocarbostyrils narciclasine, pancratistatin, lycorane, lycorine, crinane, and haemanthamine inhibit phenomena related to cancer progression in vitro. To achieve this, we examined the proliferation, adhesion, and invasion of cultured human colon cancer cells via MTT assay and Matrigel-coated Boyden chambers. In addition, Luminex assays were used to quantify the secretion of matrix metalloproteinases (MMP) and cytokines associated with poor clinical outcomes. We found that all alkaloids decreased cell proliferation regardless of TP53 status, with narciclasine exhibiting the greatest potency. The effects on cell proliferation also appear to be specific to cancer cells. Narciclasine, lycorine, and haemanthamine decrease both adhesion and invasion but with various potencies depending on the cell line. In addition, narciclasine, lycorine, and haemanthamine decreased the secretion of MMP-1, -2, and -7, as well as the secretion of the cytokines pentraxin 3 and vascular endothelial growth factor. In conclusion, the present study shows that Amaryllidaceae alkaloids decrease phenomena and cytokines associated with colorectal cancer progression, supporting future investigations regarding their potential as multifaceted drug candidates.

[Unintended Observations Leading to Macrophage Growth and Neutrophil Factor Research]

My research area in the pharmaceutical industry is innate immunity, especially in phagocytic cells. First, I studied the heat-stable growth factor of peripheral macrophages in tumorous ascitic fluid and found that lipoproteins are an influencing factor. Later, my colleagues and I found that lipid-containing substances, namely, oxidized low-density lipoprotein, dead neutrophils, or purified lipids that could be scavenged by macrophages, induce their growth. From the series of this study, I concluded that phagocytic substances induce macrophage growth by autocrine stimulation of granulocyte-macrophage colony-stimulating factor (GM-CSF). During the study, we found that neutrophils have growth-inhibitory effects against a variety of cells. Then, I elucidated that the primary factor is a zinc-binding protein, calprotectin, an abundant protein complex in the neutrophil cytosol. I found that calprotectin induces apoptosis in many cell types, including tumor cells and normal fibroblasts, and that the zinc-binding capacity is essential for its activity. Microscopic observations revealed that neutrophil extract contains factor-inducing three-dimensional cell aggregation of human mammary carcinoma, MCF-7. I elucidated that cathepsin G is responsible for this activity and that its effect is dependent on the activation of insulin-like growth factor-1. I believe that this modest, albeit novel, observation was crucial to my thirty-nine-year-long career researching phagocytic cells.

Neonatal Sepsis-Newer Insights

Sepsis is one of the leading causes of mortality and morbidity among neonates worldwide and especially affects the preterm neonates in resource-restricted settings. The infection may be acquired in utero, from the mother's genital tract or postnatally from the community or hospital environment and personnel. Factors including the time of exposure, size of the inoculum, immunity in the host, and virulence of the infectious agent affect the severity and course of illness. Culture-independent diagnostics, sepsis prediction scores, antibiotic stewardship, and preventive strategies including hand hygiene are ongoing efforts for reducing the neonatal sepsis burden.

A systematic review and meta-analyses of interleukin-1 receptor associated kinase 3 (IRAK3) action on inflammation in in vivo models for the study of sepsis

Background

Interleukin-1 receptor associated kinase 3 (IRAK3) is a critical modulator of inflammation and is associated with endotoxin tolerance and sepsis. Although IRAK3 is known as a negative regulator of inflammation, several studies have reported opposing functions, and the temporal actions of IRAK3 on inflammation remain unclear. A systematic review and meta-analyses were performed to investigate IRAK3 expression and its effects on inflammatory markers (TNF-α and IL-6) after one- or two-challenge interventions, which mimic the hyperinflammatory and immunosuppression phases of sepsis, respectively, using human or animal in vivo models.

Methods

This systematic review and meta-analyses has been registered in the Open Science Framework (OSF) (Registration DOI: 10.17605/OSF.IO/V39UR). A systematic search was performed to identify in vivo studies reporting outcome measures of expression of IRAK3 and inflammatory markers. Meta-analyses were performed where sufficient data was available.

Results

The search identified 7778 studies for screening. After screening titles, abstracts and full texts, a total of 49 studies were included in the systematic review. The review identified significant increase of IRAK3 mRNA and protein expression at different times in humans compared to rodents following one-challenge, whereas the increases of IL-6 and TNF-α protein expression in humans were similar to rodent in vivo models. Meta-analyses confirmed the inhibitory effect of IRAK3 on TNF-α mRNA and protein expression after two challenges.

Conclusions

A negative correlation between IRAK3 and TNF-α expression in rodents following two challenges demonstrates the association of IRAK3 in the immunosuppression phase of sepsis. Species differences in underlying biology affect the translatability of immune responses of animal models to human, as shown by the dissimilarity in patterns of IRAK3 mRNA and protein expression between humans and rodents following one challenge that are further influenced by variations in experimental procedures.

The potential value of plasma receptor interacting protein 3 in neonates with culture-positive late-onset sepsis

Background

Late-onset sepsis (LOS) is a systemic inflammatory response syndrome in neonates, and the molecular mechanism of LOS is incompletely characterized. The purpose of this study was to explore the potential value of receptor interacting protein 3 (RIP3) in LOS.

Methods

63 neonates with LOS supported by positive culture and 79 neonates without sepsis were enrolled in this study from September 2019 to March 2021. Plasma RIP3 was detected by enzyme-linked immunosorbent assay (ELISA) and assessed along with the whole blood hypersensitive C-reactive protein (hs-CRP) level and platelet count (PLT). Differences in RIP3, hs-CRP and PLT between the two groups were compared. Changes in the three indicators in sepsis were also observed after treatment. The diagnostic value of indicators for LOS was evaluated by receiver operating characteristic (ROC) curve analysis.

Results

In the sepsis group, RIP3 and hs-CRP levels were significantly higher than those in the control group (RIP3, p < 0.0001; hs-CRP, p < 0.0001), and PLT was significantly lower than that in the control group (p < 0.0001). After treatment, RIP3 and hs-CRP levels among septic survivors were significantly decreased (p < 0.0001) and PLT significantly improved (p = 0.0216). With RIP3 > 15,845.19 pg/mL, hs-CRP > 5.00 mg/L, and PLT < 204.00 × 10⁹/L as the positive criteria, the sensitivity values of the three indicators in the diagnosis of LOS were 69.8%, 60.3%, 60.3%, respectively, and the specificity values were 92.4%, 96.2%, 79.8%, respectively. The combination of RIP3, hs-CRP and PLT had a sensitivity of 77.8% and specificity of 97.5%.

Conclusions

RIP3 may contribute to the early diagnosis of LOS and monitoring of treatment effect. The combined detection of RIP3, hs-CRP and PLT may be more effective than individual detection in the diagnosis of LOS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06636-0.

Narciclasine attenuates LPS-induced acute lung injury in neonatal rats through suppressing inflammation and oxidative stress

Acute lung injury (ALI) is a life-threatening disorder related to serious pulmonary inflammation. Narciclasine exhibits strong anti-inflammation activity and attenuates the reactive oxygen species (ROS) production. The present study aims to investigate the underlying mechanism related to the effect of narciclasine on the pathogenesis of neonatal acute lung injury (ALI). Narciclasine attenuated LPS-induced pathological injury and pulmonary edema. In addition, narciclasine suppressed the secretion of inflammatory cytokines, including necrosis factor-α (TNF-α), Interleukin (IL-6), IL-1β, monocyte chemotactic protein-1 (MCP-1) in serum, and inhibited the expressions of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in lung tissues of neonatal ALI rats. Furthermore, narciclasine alleviated oxidative stress and apoptosis in lung tissues. Importantly, narciclasine exerted an inhibition effect on NF-κB nuclear translocation and activation of Toll-like Receptor 4 (TLR4)/Nuclear factor (NF)-κB/Cyclooxygenase 2 (Cox2) signaling pathway. Taken together, narciclasine protected against lung injury via inhibition effect on excessive inflammation, oxidative stress and apoptosis, hence, narciclasine may be considered as an effective and novel agent for clinical therapeutic strategy of ALI Treatment.

Narciclasine attenuates sepsis-induced myocardial injury by modulating autophagy

Acute myocardial injury (AMI) is often secondary to sepsis, which is a life-threatening disease associated with severe cardiac inflammation. Narciclasine, a plant alkaloid isolated from different members of the Amaryllidaceae family, has been extensively characterized as an antitumor and anti-inflammatory compound. In addition, autophagy is critical for sepsis-induced myocardial injury. However, the role and mechanism of autophagy by which narciclasine confers cardioprotection are still unclear. The present study aimed to investigate the underlying mechanism by which narciclasine affects the pathogenesis of sepsis-induced myocardial injury. Narciclasine effectively attenuated LPS-induced myocardial inflammation in vitro and in vivo. In addition, narciclasine protected cardiac function and suppressed the expression of inflammatory cytokines in LPS-induced heart tissue. Furthermore, narciclasine upregulated LPS-induced autophagic activity, and the autophagy inhibitor 3-MA abrogated narciclasine-mediated protection against LPS-induced AMI. Importantly, narciclasine exerted an inhibitory effect on the JNK signaling pathway, and JNK activity was tightly associated with narciclasine-induced autophagy and the consequent protective effects during AMI. Taken together, our findings indicate that narciclasine protects against LPS-induced AMI by inducing JNK-dependent autophagic flux; hence, narciclasine may be an effective and novel agent for the clinical treatment of sepsis-induced myocardial injury.

S100A8/A9 in Myocardial Infarction: A Promising Biomarker and Therapeutic Target

Myocardial infarction (MI), the main cause of cardiovascular-related deaths worldwide, has long been a hot topic because of its threat to public health. S100A8/A9 has recently attracted an increasing amount of interest as a crucial alarmin that regulates the pathogenesis of cardiovascular disease after its release from myeloid cells. However, the role of S100A8/A9 in the etiology of MI is not well understood. Here, we elaborate on the critical roles and potential mechanisms of S100A8/A9 driving the pathogenesis of MI. First, cellular source of S100A8/A9 in infarcted heart is discussed. Then we highlight the effect of S100A8/A9 heterodimer in the early inflammatory period and the late reparative period of MI as well as myocardial ischemia/reperfusion (I/R) injury. Moreover, the predictive value of S100A8/A9 for the risk of recurrence of cardiovascular events is elucidated. Therefore, this review focuses on the molecular mechanisms of S100A8/A9 in MI pathogenesis to provide a promising biomarker and therapeutic target for MI.

Prediction of repurposed drugs for treating lung injury in COVID-19

Background: Coronavirus disease (COVID-19) is an infectious disease discovered in 2019 and currently in outbreak across the world. Lung injury with severe respiratory failure is the leading cause of death in COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, there still lacks efficient treatment for COVID-19 induced lung injury and acute respiratory failure. Methods: Inhibition of angiotensin-converting enzyme 2 (ACE2) caused by the spike protein of SARS-CoV-2 is the most plausible mechanism of lung injury in COVID-19. We performed drug repositioning analysis to identify drug candidates that reverse gene expression pattern in L1000 lung cell line HCC515 treated with ACE2 inhibitor. We confirmed these drug candidates by similar bioinformatics analysis using lung tissues from patients deceased from COVID-19. We further investigated deregulated genes and pathways related to lung injury, as well as the gene-pathway-drug candidate relationships. Results: We propose two candidate drugs, COL-3 (a chemically modified tetracycline) and CGP-60474 (a cyclin-dependent kinase inhibitor), for treating lung injuries in COVID-19. Further bioinformatics analysis shows that 12 significantly enriched pathways (P-value <0.05) overlap between HCC515 cells treated with ACE2 inhibitor and human COVID-19 patient lung tissues. These include signaling pathways known to be associated with lung injury such as TNF signaling, MAPK signaling and chemokine signaling pathways. All 12 pathways are targeted in COL-3 treated HCC515 cells, in which genes such as RHOA, RAC2, FAS, CDC42 have reduced expression. CGP-60474 shares 11 of 12 pathways with COL-3 and common target genes such as RHOA. It also uniquely targets other genes related to lung injury, such as CALR and MMP14. Conclusions: This study shows that ACE2 inhibition is likely part of the mechanisms leading to lung injury in COVID-19, and that compounds such as COL-3 and CGP-60474 have potential as repurposed drugs for its treatment.