FK866 attenuates sepsis-induced acute lung injury through c-jun-N-terminal kinase (JNK)-dependent autophagy

Anisodamine Hydrobromide ameliorates acute lung injury via inhibiting pyroptosis in murine sepsis model

OBJECTIVE

Sepsis can have severe implications on lung function, leading to acute lung injury (ALI), a major contributor to sepsis-related mortality. Anisodamine hydrobromide (Ani HBr), a bioactive constituent derived from the root of Scopolia tangutica Maxim, a plant endemic to China, has demonstrated efficacy in treating septic shock. We aim to explore whether Ani HBr can alleviate sepsis-triggered acute lung injury (ALI) and elucidate the fundamental mechanisms involved.

MATERIALS AND METHOD

The protective effects of Ani HBr were assessed in two models: in vitro, lipopolysaccharide (LPS)-stimulated RAW264.7 cells, and in vivo, cecal ligation puncture (CLP)-induced sepsis. To measure the cell viability of RAW264.7 cells after Ani HBr treatment, we used the CCK-8 assay. We quantified the levels of pro-inflammatory cytokines expression using ELISA. We also measured the expression of pyrotosis indicators by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR), Western blotting, and immunofluorescence.

RESULTS

Our study demonstrates that Ani HBr can alleviate pulmonary edema, bleeding, and excessive inflammation induced by CLP. Additionally, it exhibits protective effects against cytotoxicity induced by LPS in RAW264.7 macrophage cells. Furthermore, Ani HBr downregulates the mRNA and protein levels of NLRP3, Caspase-1, GSDMD, IL-18, and IL-1β in both animal models and cell cultures, thereby inhibiting pyroptosis in a similar mechanism to AC-YVAD-CMK (AYC)'s blockade of Caspase-1. Moreover, Ani HBr suppresses the production and release of proinflammatory cytokines.

CONCLUSION

These findings suggest that Ani HBr could serve as a protective agent against sepsis-induced ALI by suppressing pyroptosis.

Design of FK866-Based Degraders for Blocking the Nonenzymatic Functions of Nicotinamide Phosphoribosyltransferase

Nicotinamide phosphoribosyltransferase (NAMPT) is an attractive therapeutic target for treating select cancers. There are two forms of NAMPT: intracellular NAMPT (iNAMPT, the rate-limiting enzyme in the mammalian NAD+ main synthetic pathway) and extracellular NAMPT (eNAMPT, a cytokine with protumorigenic function). Reported NAMPT inhibitors only inhibit iNAMPT and show potent activities in preclinical studies. Unfortunately, they failed to show efficacy due to futility and toxicity. We developed a series of FK866-based NAMPT-targeting PROTACs and identified LYP-8 as a potent and effective NAMPT degrader that simultaneously diminished iNAMPT and eNAMPT. Importantly, LYP-8 demonstrated superior efficacy and safety in mice when compared to the clinical candidate, FK866. This study highlights the importance and feasibility of applying PROTACs as a superior strategy for interfering with both the enzymatic function of NAMPT (iNAMPT) and nonenzymatic function of NAMPT (eNAMPT), which is difficult to achieve with conventional NAMPT inhibitors.

Palmatine Attenuated Lipopolysaccharide-Induced Acute Lung Injury by Inhibiting M1 Phenotype Macrophage Polarization via NAMPT/TLR2/CCR1 Signaling

The present work was conducted to research the potential mechanism of palmatine (PAL) on lipopolysaccharide (LPS)-caused acute lung injury (ALI). Network pharmacology and bioinformatic analyses were carried out. Mice were intragastrically treated with PAL and intratracheally stimulated with LPS. LPS-induced RAW264.7 cells were employed for the in vitro model. The MPO activity, W/D ratio, neutrophils, total cell number in BALF, and histopathological alteration were examined. The levels of TNF-α, IL-1β, IL-6, IL-18, IL-4, and IL-10 in serum, BALF, and supernatant were examined by ELISA. The mRNA expressions of iNOS, CD68, Arg1, Ym1, and CD206 and protein expressions of NAMPT, TLR2, CCR1, and NLRP3 inflammasome were detected by PCR, WB, and immunofluorescence. The NAMPT inhibitor FK866, TLR2 inhibitor C29, CCR1 inhibitor BX471, NAMPT-overexpression (OE) plasmid, and TLR2-OE plasmid were used for mechanism research. As a result, PAL relieved the symptoms of ALI. PAL inhibited M1 phenotype indices and promoted M2 phenotype indices in both LPS-induced mice and RAW264.7 cells. PAL also inhibited the expressions of NAMPT, TLR2, CCR1, and NLRP3 inflammasome. The treatments with FK866, NAMPT-OE plasmid, C29, TLR2-OE plasmid, and BX471 proved that PAL exerted its effect via NAMPT/TLR2/CCR1. Molecular docking suggested that PAL might combine with NAMPT. In conclusion, PAL ameliorated LPS-induced ALI by inhibiting M1 phenotype macrophage polarization via NAMPT/TLR2/CCR1 signaling.

Tomatidine activates autophagy to improve lung injury and inflammation in sepsis by inhibiting NF-κB and MAPK pathways

Sepsis-induced acute lung injury (ALI) is a life-threatening medical condition with high mortality and morbidity. Autophagy is involved in the pathophysiological process of sepsis-induced ALI, including inflammation, which indicates that regulating autophagy may be beneficial for this disease. Tomatidine, a natural compound abundant in unripe tomatoes, has been reported to have anti-inflammatory, anti-tumorigenic, and lipid-lowering effects. However, the biological functions and mechanisms of tomatidine in sepsis-induced ALI remain unknown. The principal objective of this study was to investigate the effect of tomatidine on sepsis-induced ALI. Cecal ligation and puncture (CLP) was used to induce septic lung injury in mice, and 10 mg/kg tomatidine was intraperitoneally injected into mice 2 h after the operation. The results of hematoxylin and eosin staining and assessment of lung edema and total protein levels in bronchoalveolar lavage fluid (BALF) demonstrated that tomatidine alleviated CLP-induced severe lung injuries such as hemorrhage, infiltration of inflammatory cells, and interstitial and alveolar edema in mice. Additionally, the levels of proinflammatory cytokines in BALF and lung tissues were measured by enzyme-linked immunosorbent assay (ELISA), and the results showed that tomatidine inhibited CLP-induced inflammatory damage to lungs. Moreover, the results of western blotting showed that tomatidine promoted autophagy during CLP-induced ALI. Mechanistically, immunofluorescence staining and western blotting were used to measure the protein levels of TLR4, phosphorylated NF-κB, phosphorylated IκBα, and phosphorylated MAPKs, showing that tomatidine inactivated NF-κB and MAPK signaling in lung tissues of CLP-induced ALI mice. In conclusion, tomatidine exerts protective effects against sepsis-induced severe damage to the lungs by inhibiting inflammation and activating autophagy in CLP-treated mice through inactivating the NF-κB and MAPK pathways, which may be an effective candidate for treating septic ALI.

Effects of the PI3K/Akt/HO-1 pathway on autophagy in a sepsis-induced acute lung injury mouse model

Sepsis-induced lung injury is an acute hypoxic respiratory insufficiency caused by systemic infectious factors that results in alveolar epithelial cell and capillary endothelial cell injury, diffuse pulmonary interstitial edema, and alveolar edema. Heme oxygenase (HO)-1 is usually associated with inflammation and has anti-inflammatory effects. Autophagy is a degradation pathway that eliminates cellular metabolic waste and plays an important protective role during stress. The phosphatidylinositol 3-kinase/ protein kinase B (PI3K/Akt) signaling pathway plays a key role in mediating cellular responses to inflammatory reactions. Therefore, we hypothesized that HO-1 is associated with autophagy and regulated by the PI3K/Akt signaling pathway in mice with sepsis-induced lung injury. Sepsis-induced lung injury was induced in mice using cecal ligation and puncture (CLP). Hemin or Sn-protoporphyrin IX (SnPP) was administered via intraperitoneal injection before surgery. Survival rates were observed during days 1-7 after the surgery; lung histology was discerned 24 h after the surgery; pro-inflammatory and anti-inflammatory factors in plasma and lung tissue were measured using enzyme-linked immunosorbent assay (ELISA); HO-1, Beclin-1, microtubule-associated protein 1 light chain 3B (LC3B)-II, p62 and lysosome associated membrane protein (LAMP)2 protein expression levels were measured 24 h after the surgery; HO-1 and LC3B-II protein expression levels were observed using immunofluorescence 24 h after the surgery; and autophagosomes were detected using electron microscopy 24 h after the surgery. Furthermore, when PI3K inhibitors LY294002, PI3K activators Recilisib and hemin were administered before the surgery, Akt, p-Akt, HO-1, and LC3-II levels were measured 24 h post-surgery. We found that HO-1 overexpression increased the survival rate and inhibited sepsis-induced lung injury. HO-1 overexpression attenuated the levels of proinflammatory cytokines (TNF-α, IL-1β) and increased the anti-inflammatory cytokine (IL-10, HO-1) overexpression. Moreover, HO-1 overexpression was also associated with increased expression of Beclin-1, LC3B-II and LAMP2 protein expression; decreased p62 protein expression; and significantly increased autophagosome formation. The results for HO-1-downregulated mice contrasted with those mentioned above. LY294002 inhibited p-Akt/Akt, HO-1, and LC3B-II protein expression; and hemin reversed the inhibitory effect of LY294002. The protective effect of HO-1 was involved in the mediation of autophagy, which may be regulated by the PI3K/Akt signaling pathway during sepsis-induced lung injury in mice.

Autophagy in sepsis-induced acute lung injury: Friend or foe?

Sepsis-induced acute lung injury (ALI) is a life-threatening syndrome with high mortality and morbidity, resulting in a heavy burden on family and society. As a key factor that maintains cellular homeostasis, autophagy is regarded as a self-digesting process by which damaged organelles and useless proteins are recycled for cell metabolism, and it thus plays a crucial role during physiological and pathological processes. Recent studies have indicated that autophagy is involved in the pathophysiological process of sepsis-induced ALI, including cell apoptosis, inflammation, and mitochondrial dysfunction, which indicates that regulating autophagy may be beneficial for this disease. However, the role of autophagy in the etiology and treatment of sepsis-induced ALI is not well characterized. This review summarizes the autophagy-related signaling pathways in sepsis-induced ALI, as well as focuses on the dual role of autophagy and its regulation by non-coding RNAs during disease progression, for the development of potential therapeutic strategies in this disease.

Application and value of hydrogen sulfide modulated autophagy in sepsis

Sepsis is is anabnormalhost immune responsecausedbyinfection. Antibiotics, anti-viral drugs, and vasoactive drugs have always been used in the traditional treatment of sepsis, but there are no specific and effective drugs in clinical practice. Autophagy is a highly conservative process in biological evolution, and plays an important role in maintaining intracellular homeostasis and cellular self-renewal. Autophagy can remove and degrade misfolding proteins and damaged organelles in cells, providing materials for cell repair and self-renewal. Hydrogen sulfide (H2S) is a colorless gas that smells likerotteneggs. It is the third endogenous gas signal molecule discovered after nitric oxide and carbon monoxide and has become a research hotspot in recent years. H2S has a variety of biological functions and plays an important role in various physiological and pathological processes. Thereisgrowingevidencethat H2S can regulate autophagy. The intervention of autophagy is a promising therapeutic strategy to improve sepsis organ damage. This article reviews the organ protection of autophagy in sepsis and the role of H2S in regulating autophagy in sepsis, revealing that H2S intervention with autophagy may be a a worthy target in sepsis treatment.

NAMPT inhibition relieves intestinal inflammation by regulating macrophage activation in experimental necrotizing enterocolitis

Nicotinamide phosphoribosyl transferase (NAMPT) is associated with various NAD+ -consuming enzymatic reactions. The precise role in intestinal mucosal immunity in necrotizing enterocolitis (NEC) is not well defined. Here, we examined whether NAMPT inhibition by the highly specific inhibitor FK866 could alleviate intestinal inflammation during the pathogenesis of NEC. In the present study, we showed that NAMPT expression was upregulated in the human terminal ileum of human infants with NEC. FK866 administration attenuated M1 macrophage polarization and relieved the symptoms of experimental NEC pups. FK866 inhibited intercellular NAD+ levels, macrophage M1 polarization, and the expression of NAD+ -dependent enzymes, such as poly (ADP ribose) polymerase 1 (PARP1) and Sirt6. Consistently, the capacity of macrophages to phagocytose zymosan particles, as well as antibacterial activity, were impaired by FK866, whereas NMN supplementation to restore NAD+ levels reversed the changes in phagocytosis and antibacterial activity. In conclusion, FK866 reduced intestinal macrophage infiltration and skewed macrophage polarization, which is implicated in intestinal mucosal immunity, thereby promoting the survival of NEC pups.

Research Progress on Autophagy Regulation by Active Ingredients of Traditional Chinese Medicine in the Treatment of Acute Lung Injury

Autophagy is a highly conserved process that maintains cell stability in eukaryotes, participates in the turnover of intracellular substances to maintain cell function, helps to resist pathogen invasion, and improves cell tolerance to environmental changes. Autophagy has been observed in many diseases, and the symptoms of these diseases are significantly improved by regulating autophagy. Autophagy is also involved in the development of lung diseases. Studies have shown that autophagy may play a beneficial or harmful role in acute lung injury (ALI), and ALI has been treated with traditional Chinese medicine designed to promote or inhibit autophagy. In this paper, the molecular mechanism and common pathways regulating autophagy and the relationship between autophagy and ALI are introduced, and the active ingredients of traditional Chinese medicine that improve ALI symptoms by regulating autophagy are summarized.

Neutrophil Membrane-Coated Therapeutic Liposomes for Targeted Treatment in Acute Lung Injury

Acute lung injury (ALI) is one of the most common comorbidities associated with sepsis and can lead to acute respiratory distress syndrome. Intense inflammatory response due to excessive activation and uncontrolled infiltration of neutrophils are the central processes in the development of sepsis-induced ALI. In this study, a biomimetic nanoplatform that is a neutrophil membrane-coated liposome-loaded acidic fibroblast growth factor (aFGF@NMLs), which can selectively target the inflamed lung and effectively alleviate sepsis-induced ALI via inflammation suppression, was constructed. In vitro findings revealed that aFGF@NMLs has pro-inflammatory cytokine binding capabilities and can promote cellular uptake, substantially attenuate inflammatory responses, and enhance cellular antioxidant capacity. The in vivo results show that aFGF@NMLs can specifically accumulate in injured lungs in ALI mice after intravenous injection, thereby reducing the secretion of pro-inflammatory cytokines, inhibiting pulmonary cell apoptosis, and promoting lung function recovery. In conclusion, aFGF@NMLs demonstrated anti-inflammatory effects, mitigated the progression of ALI, and contributed to the disease prognosis. This research offers an innovative strategy and concept for the clinical treatment of diseases related to pulmonary inflammation.

Utilising Network Pharmacology to Explore Underlying Mechanism of Astragalus membranaceus in Improving Sepsis-Induced Inflammatory Response by Regulating the Balance of IκBα and NF-κB in Rats

Objective

The purpose of the present study was to explore the mechanism of Astragalus membranaceus in the treatment of sepsis.

Methods

We searched the active components and targets of Astragalus membranaceus using the TCMSP and BATMAN databases. Then, the GeneCards, MalaCards, and OMIM databases were used to screen out relevant targets of sepsis. The common targets of the former two gene sets were uploaded to the STRING database to create an interaction network. DAVID was used to perform KEGG enrichment analysis of the core targets. Based on the results of KEGG and previous studies, key pathways for the development of sepsis were identified and experimentally validated.

Result

We obtained 3,370 sepsis-related targets in databases and 59 active components in Astragalus membranaceus through data mining, corresponding to 1,130 targets. The intersection of the two types of targets led to a total of 318 common targets and 84 core targets were obtained after screening again. The KEGG and previous studies showed that these 84 core targets were involved in sepsis by regulating TNF, MAPK, and PI3K pathways. TNF, MAPK8, NF-κB, and IκBα are crucial in sepsis. Experimental validation demonstrated that some markers in sepsis model rats were improved after the intervention with Astragalus granules and their chemical components. Among them, IL-1β, IL-6, and TNF-α in rat serum were reduced. The mRNA and protein expression of TNF-α, IL-6, MMP9, MAPK8, and NF-κB were reduced in rat blood. However, the mRNA and protein expression of IκBα and PI3K were increased in rat blood.

Conclusion

The AST could affect the TNF, PI3K, and MAPK pathway cascade responses centred on IκBα and NF-κB, attenuate the expression of IL-6 and MMP9, and interfere with the inflammatory response during sepsis.

A new cell death program regulated by toll-like receptor 9 through p38 mitogen-activated protein kinase signaling pathway in a neonatal rat model with sepsis associated encephalopathy

Background:

Sepsis, a serious condition with high mortality, usually causes sepsis associated encephalopathy (SAE) that involves neuronal cell death. However, the cell death programs involved and their underlying mechanisms are not clear. This study aimed to explore the regulatory mechanisms of different cell death programs in SAE.

Methods:

A neonatal rat model of SAE was established by cecal ligation and perforation. Survival rate and vital signs (mean arterial pressure and heart rate) were monitored, nerve reflexes were evaluated, and cortical pathological changes were observed by hematoxylin and eosin staining. The expression of pyroptosis, apoptosis, and necroptosis (PANoptosis)-related proteins, mitogen- activated protein kinase (MAPK), and its upstream regulator toll-like receptor 9 (TLR9) were detected. The expression of TLR9 in neurons was observed by immunofluorescence staining. The ultrastructure of neurons was observed by transmission electron microscope.

Results:

First, PANoptosis was found in cortical nerve cells of the SAE rats. Meanwhile, the subunits of MAPKs, p38 MAPK, Jun N- terminal kinase, and extracellular signal-regulated kinase (ERK) were activated. After pharmacologically inhibiting each of the subunits, only p38 MAPK was found to be associated with PANoptosis. Furthermore, blocking the p38 MAPK signaling pathway activated necroptosis but inhibited apoptosis and pyroptosis. When necroptosis was pharmacologically inhibited, apoptosis and pyroptosis were reactivated. Finally, we found that the expression of TLR9, a regulator of MAPKs, was significantly increased in this model. After down-regulation of TLR9, p38 MAPK, and ERK signaling pathways were inhibited, which led to the inhibition of PANoptosis. Further analysis found that down-regulation of TLR9 improved the survival rate and reduced the pathological changes in SAE rats.

Conclusions:

Our study showed that the programs comprising PANoptosis are activated simultaneously in SAE rats. TLR9 activated PANoptosis through the p38 MAPK signaling pathway. TLR9 may work as a potential target for SAE treatment.

Nampt promotes fibroblast extracellular matrix degradation in stress urinary incontinence by inhibiting autophagy

Stress urinary incontinence (SUI) is defined as involuntary urinary leakage happening in exertion. Nicotinamide phosphoribosyltransferase (Nampt) is seldom researched in the pathogenesis of SUI. Accordingly, the current study set out to elucidate the role of Nampt in SUI progression. Firstly, we determined Nampt expression patterns in SUI patients and rat models. In addition, fibroblasts were obtained from the anterior vaginal wall tissues of non-SUI patients and subjected to treatment with different concentrations of interleukin-1β (IL-1β), followed by quantification of Nampt expressions in fibroblasts. Subsequently, an appropriate concentration of IL-1β was selected to treat anterior vaginal wall fibroblasts. Nampt was further silenced in IL-1β-treated fibroblasts to assess the role of Nampt in autophagy and extracellular matrix (ECM) degradation. Lastly, functional rescue assays were carried out to inhibit autophagy and evaluate the role of autophagy in the mechanism of Nampt modulating IL-1β-treated fibroblast ECM degradation. It was found that Nampt was highly-expressed in SUI patients and rat models and IL-1β-treated fibroblasts. On the other hand, Nampt silencing was found to suppress ECM degradation and promote SUI fibroblast autophagy. Additionally, inhibition of autophagy attenuated the inhibitory effects of Nampt silencing on SUI fibroblast ECM degradation. Collectively, our findings revealed that Nampt was over-expressed in SUI, whereas Nampt silencing enhanced SUI fibroblast autophagy, and thereby inhibited ECM degradation.

Octanoic acid-rich enteral nutrition prevented lipopolysaccharide-induced acute liver injury through c-Jun N-terminal kinase-dependent autophagy

BACKGROUND

Acute liver injury (ALI) is an essential component of sepsis associated with poor outcomes. Octanoic acid (OA), a medium-chain fatty acid, has a protective effect on sepsis-induced organ damage, and autophagy is an adaptive response to sepsis. However, the underlying mechanism by which OA prevents ALI remains unknown. Therefore, we investigated whether OA-rich enteral nutrition (EN) prevented lipopolysaccharide (LPS)-induced ALI through the c-Jun N-terminal kinase (JNK)-dependent autophagy.

METHODS

Firstly, Sprague Dawley rats were randomly divided into four groups (sham, LPS, LPS + EN, and LPS + EN + OA) to detect the effect of OA-rich EN on LPS-induced ALI. Then, rats were randomly divided into five groups (sham, LPS, LPS + EN + OA, LPS + EN + OA + anisomycin (AN), and LPS + SP600125) to explore the mechanism by which OA-rich EN prevented ALI. EN and OA-rich EN were conducted through gastric tubes for 3 days. The liver protective effects were measured by liver histopathological changes, enzymes, inflammatory cytokines of serum and liver, the levels of autophagy, and JNK activity.

RESULTS

OA-rich EN inhibited JNK activity, up-regulated autophagy and prevented LPS-induced ALI. Inhibition of JNK activity conferred by SP promoted autophagy and prevented LPS-induced ALI. Moreover, the protective effect of autophagy and inhibition of JNK activity conferred by OA-rich EN on ALI was counteracted by AN.

CONCLUSION

OA-rich EN prevented LPS-induced ALI through JNK-dependent autophagy. This result suggested that OA-rich EN may be a therapeutic potential for ALI in patients with sepsis.

Endothelial dysfunction: a therapeutic target in bacterial sepsis?

INTRODUCTION

Endothelial cells maintain vascular integrity, tone, and patency and have important roles in hemostasis and inflammatory responses. Although some degree of endothelial dysfunction with increased vascular permeability may be necessary to control local infection, excessive dysfunction plays a central role in the pathogenesis of sepsis-related organ dysfunction and failure as it results in dysregulated inflammation, vascular leakage, and abnormal coagulation. The vascular endothelium has thus been proposed as a potential target for therapeutic intervention in patients with sepsis.

AREAS COVERED

Different mechanisms underlying sepsis-related dysfunction of the vascular endothelium are discussed, including glycocalyx shedding, nitrosative stress, and coagulation factors. Potential therapeutic implications of each mechanism are mentioned.

EXPERT OPINION

Multiple targets to protect or restore endothelial function have been suggested, but endothelium-driven treatments remain a future potential at present. As some endothelial dysfunction and permeability may be necessary to remove infection and repair damaged tissue, targeting the endothelium may be a particular challenge. Ideally, therapies should be guided by biomarkers related to that specific pathway to ensure they are given only to patients most likely to respond. This enrichment based on biological plausibility and theragnostics will increase the likelihood of a beneficial response in individual patients and enable more personalized treatment.

Apoptosis signal-regulating kinase 1 (ASK1) inhibition reduces endothelial cytokine production without improving permeability after toll-like receptor 4 (TLR4) challenge

Sepsis represents a life-threatening event often mediated by the host's response to pathogens such as gram-negative organisms, which release the proinflammatory lipopolysaccharide (LPS). Within the endothelium, the mitogen-activated protein kinase (MAPK) pathway is an important driver of endothelial injury during sepsis, of which oxidant-sensitive apoptosis signal-regulating kinase 1 (ASK1) is postulated to be a critical upstream regulator. We hypothesized that ASK1 would play a key role in endothelial inflammation during bacterial challenge. Utilizing RNA sequencing data from patients and cultured human microvascular endothelial cells (HMVECs), ASK1 expression was increased in sepsis and after LPS challenge. Two ASK1 inhibitors, GS444217 and MSC2023964A, reduced cytokine production in HMVECs following LPS stimulation, but had no effect on permeability as measured by transendothelial electrical resistance and intercellular space. MAPKs are known to interact with endothelial nitric oxide synthase (eNOS) and ASK1 expression levels correlated with eNOS expression in patients with septic shock. In addition, eNOS physically interacted with ASK1, though this interaction was not altered by ASK1 inhibition, nor did inhibition alter MAPK p38 activity. Instead, among MAPKs, ASK1 inhibition only impaired LPS-induced JNK phosphorylation. The reduction in JNK activation caused by ASK1 inhibition impaired JNK-mediated cytokine production without affecting permeability. Thus, LPS triggers JNK-dependent cytokine production that requires ASK1 activation, but both its effects on permeability and activation of p38 are ASK1-independent. These data demonstrate how distinct MAPK signaling pathways regulate endothelial inflammatory outputs during acute infectious challenge.

Inhibition of nicotinamide phosphoribosyltransferase protects against acute pancreatitis via modulating macrophage polarization and its related metabolites

BACKGROUND & OBJECTIVES

Acute pancreatitis is a common inflammatory disorder of the exocrine pancreas with no specific therapy. Intracellular nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in nicotinamide adenine dinucleotide (NAD) salvage pathway, is involved in many inflammatory disorders. In this study, we investigated the role of NAMPT in experimental acute pancreatitis.

METHODS

Acute pancreatitis was induced in mice using three disparate models: (1) caerulein hyperstimulation, (2) ethanol plus palmitoleic acid, and (3) retrograde biliopancreatic ductal infusion of sodium taurocholate. The NAMPT inhibitor FK866 and NAMPT downstream product nicotinamide mononucleotide (NMN) was administered. Serum and pancreas were collected and analyzed biochemically and histologically. Bone marrow derived macrophages were isolated, cultured with cytokines or pancreatic acini, then analyzed by quantitative PCR and non-targeted metabolomics.

RESULTS

The levels of pancreatic NAMPT and NAD were down-regulated upon acute pancreatitis. NAMPT inhibitor FK866 suppressed M1 macrophage polarization while NMN boosted it. In co-culture of macrophages with acinar cells, inhibition of NAMPT prevented M1-like macrophage differentiation induced by injured pancreatic acini. The injured pancreatic acinar milieu induced a unique metabolic signature linked to macrophage polarization, and inhibition of NAMPT reversed these metabolites changes. Furthermore, NMN supplementation aggravated caerulein hyperstimulation pancreatitis and alcoholic pancreatitis, and inhibition of NAMPT protected against caerulein hyperstimulation, alcoholic and biliary acute pancreatitis and reducing pancreatic macrophage infiltration in vivo.

CONCLUSIONS

NAMPT inhibition protects against acute pancreatitis via preventing M1 macrophage polarization and restoring the metabolites related to macrophage polarization and that NAMPT could be a promising therapeutic target for acute pancreatitis.

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.

Natural product derived phytochemicals in managing acute lung injury by multiple mechanisms

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) as common life-threatening lung diseases with high mortality rates are mostly associated with acute and severe inflammation in lungs. With increasing in-depth studies of ALI/ARDS, significant breakthroughs have been made, however, there are still no effective pharmacological therapies for treatment of ALI/ARDS. Especially, the novel coronavirus pneumonia (COVID-19) is ravaging the globe, and causes severe respiratory distress syndrome. Therefore, developing new drugs for therapy of ALI/ARDS is in great demand, which might also be helpful for treatment of COVID-19. Natural compounds have always inspired drug development, and numerous natural products have shown potential therapeutic effects on ALI/ARDS. Therefore, this review focuses on the potential therapeutic effects of natural compounds on ALI and the underlying mechanisms. Overall, the review discusses 159 compounds and summarizes more than 400 references to present the protective effects of natural compounds against ALI and the underlying mechanism.

Autophagy, Unfolded Protein Response and Lung Disease

Acute Respiratory Distress Syndrome is a severe disorder affecting thousands of individuals worldwide. The available medical countermeasures do not sufficiently suppress the unacceptable high mortality rates associated with those in need. Thus, intense efforts aim to delineate the function of the lung endothelium, so to deliver new therapeutic approaches against this disease. The present manuscript attempts to shed light on the interrelations between the unfolded protein response and autophagy towards lung disease, to deliver a new line of possible therapeutic approaches against the ferocious Acute Respiratory Distress Syndrome.