Inflammasomes: current understanding and open questions

The role of immune cells and inflammasomes in Modulating cytokine responses in HPV-Related cervical cancer

One of the most frequent cancers associated with gynecological malignancies is cervical cancer. Nearly 99% of cervical tumor lesions are produced by prolonged infection with hr-HPV and almost 70% of cases are related to HPV-16 and HPV-18. The human immune system has a crucial role in defending against infections caused by HPV infection. As an illustration, elevation in neutrophils reduces T cell antitumor activity, which in turn results in the development of malignancies and subsequently inhibits immune system function. HPV-infected cells, also, express a significant number of genes related to pro-inflammatory mediators including IL-1β. Moreover, inflammasomes, which are multi-protein complexes, owing the production of the pro-inflammatory cytokines including IL-1β and IL-18 in response to viral infections. In other words, these multi-protein complexes have a crucial role in tumor immunity regulation through the secretion of pro-inflammatory cytokines and induction of antigen presentation and maturation by APCs including dendritic cells. In this study, we attempted to investigate the inflammasome's general role in the initiation and advancement of cervical cancer, as well as a summary of the pathways connected to the possible participation of inflammasomes in the pathological process of cervical carcinoma and immune cell engagement. Novel strategy techniques that target the inflammatory reaction of tumor-related antigens may be created with an understanding of inflammasome-dependent pathways to accomplish tumor immunotherapy and cervical tumor treatment.

Association of Inflammasome Gene Expression Levels with Pathogenesis of Familial Mediterranean Fever in Armenians

Familial Mediterranean fever (FMF) is a genetically determined autoinflammatory disease transmitted mostly by an autosomal recessive mechanism and caused by point mutations of the MEFV (Mediterranean FeVer) gene. The aim of this study was to evaluate the expression of inflammasome genes (p65, Casp1, MEFV, and NLRP3) in patients with FMF compared to controls to understand the changes playing a key role in disease development. We found altered expression levels of the full-length MEFV isoform as well as Casp1 and p65 in FMF patients versus controls. This, once again, highlighted the significance of inflammasome genes in terms of FMF.

Association and interaction analysis of NLRP3 gene polymorphisms with hypertension risk: a case-control study in China

BACKGROUND

The NLRP3 inflammasome, a pivotal mechanism regulating inflammatory responses and featuring the pyrin domain containing 3 (NLRP3) within the NOD-like receptor family, is widely recognized as a central pathogenic factor in cardiovascular diseases. The present study endeavors to delve into the correlation and potential interplay between the rs10754558 polymorphism of NLRP3 and the predisposition to hypertension among the Chinese adult population.

METHODS

All the participants who came from a community in Bengbu, China were investigated by being interviewed with a questionnaire. Overall, 354 paired case-control participants were analyzed. Genomic DNA was extracted from 5ml venous blood using the Tiangen DNA extraction kit. The rs10754558 polymorphism of the NLRP3 gene was genotyped by TaqMan allelic discrimination real-time PCR.The association between the rs10754558 polymorphism and hypertension risk was investigated by a logistic regression analysis. Furthermore, an additive interaction analysis was conducted using related indicators, including the relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP), and synergy index (SI).

RESULTS

Participants carrying the GG genotype were more likely to develop hypertension than participants carrying the CC genotype (adjusted odds ratio [OR]: 2.16, 95% confidence interval [CI]: 1.33-3.52). A significant additive interaction between the NLRP3 polymorphism and obesity status concerning the risk of hypertension was observed, as estimated by all indicators: RERI (1.12, 95% CI: 0.70-1.5), AP (0.34, 95% CI: 0.14-0.53), and SI (1.92, 95% CI: 1.03-3.59). The values of RERI (1.74, 95% CI: 0.37-3.11), AP (0.46, 95% CI: 0.21-0.70), and SI (2.62, 95% CI: 1.18-5.83) showed that a significant interaction between the rs10754558 polymorphism and a family history of hypertension.

CONCLUSIONS

Our findings indicate a significant association between the NLRP3 rs10754558 polymorphism and the risk of hypertension in Chinese adults. Moreover, a notable additive interaction emerges between NLRP3 polymorphisms and obesity status, further amplifying the risk of hypertension.

Microglia-induced neuroinflammation in hippocampal neurogenesis following traumatic brain injury

Traumatic brain injury (TBI) is one of the most causes of death and disability among people, leading to a wide range of neurological deficits. The important process of neurogenesis in the hippocampus, which includes the production, maturation and integration of new neurons, is affected by TBI due to microglia activation and the inflammatory response. During brain development, microglia are involved in forming or removing synapses, regulating the number of neurons, and repairing damage. However, in response to injury, activated microglia release a variety of pro-inflammatory cytokines, chemokines and other neurotoxic mediators that exacerbate post-TBI injury. These microglia-related changes can negatively affect hippocampal neurogenesis and disrupt learning and memory processes. To date, the intracellular signaling pathways that trigger microglia activation following TBI, as well as the effects of microglia on hippocampal neurogenesis, are poorly understood. In this review article, we discuss the effects of microglia-induced neuroinflammation on hippocampal neurogenesis following TBI, as well as the intracellular signaling pathways of microglia activation.

Macrophages and Mast Cells in the Gastric Mucosa of Patients with Obesity Undergoing Sleeve Gastrectomy

Background. Adipose tissue macrophages (ATMs) and mast cells (MCs) play a role in immune responses. More recently, their involvement in tumor angiogenesis and chronic inflammatory conditions in patients with obesity has been discovered. Furthermore, a higher BMI (Body Mass Index) value corresponds to a higher inflammatory state. In particular, gastric tissue in obesity (GTO) is characterized by Macrophages, Mast Cells Positive to Triptase (MCPT), and neo-formed microvessels (MVD). Materials and Methods. We collected gastric tissue samples from December 2021 to December 2022. The patients selected had a BMI > 35 kg/m2 with different comorbidities. Regarding the surgery, surgeons executed a Laparoscopic Sleeve Gastrectomy (LapSG). Gastric tissue was analyzed by immunohistochemistry and morphometrical assay, comparing "obese-related" gastric tissue to normal gastric tissue. Furthermore, tissue parameters were correlated with important clinicopathological features. Results. We collected thirty gastric tissue samples from thirty patients with obesity. Blood tests, Electrocardiogram (ECG), esophagogastroduodenoscopy (EGDS) associated with a urea breath test, and chest X.R. were performed. A significant correlation between ATMs, MCPT, MVD, and BMI was found in GTO. Pearson t-test analysis was conducted (r ranged from 0.67 to 0.71; p-value < 0.05). Conclusions. These preliminary data suggest that ATMs, MCPT, and MVD related to BMI can play a role in both gastric tissue angiogenesis and inflammation inducing a tissue change that could lead to gastric inflammation or cancer diseases.

The roles of SFKs in the regulation of proinflammatory cytokines and NLRP3 in familial mediterranean fever patients

Familial Mediterranean Fever (FMF) is caused by mutations in pyrin, a protein produced in innate immune cells that regulates the development of interleukin (IL)-1β by interacting with caspase-1 and other components of inflammasomes. Although overexpression of proinflammatory cytokines have been observed in FMF patients, no studies have been conducted on the role of Src family kinases (SFKs). The purpose of this study was to examine the impact of SFKs on the modulation of IL-1β, IL-6, IL-8, TNF-α, and NLRP3 inflammasome in patients with FMF. The study included 20 FMF patients and 20 controls. Peripheral blood mononuclear cells (PBMCs) were isolated by density gradient centrifugation. Protein expression levels of SFKs members were measured by western blot. The effect of lipopolysaccharide-induced (LPS) activation and PP2- induced inhibition of SFKs on NLRP3 and IL-1β, IL 6, IL-8, TNF-α were examined by western blot and flow cytometry respectively. Patients with FMF have considerably greater levels of Lck expression. In addition, patients had a substantially greater basal level of NLRP3 than the control group (*p = 0.016). Most importantly, the levels of IL-1 β were elevated with LPS stimulation and reduced with PP2 inhibition in FMF patients. These results suggest that SFKs are effective in regulation of IL-1 β in FMF patients.

Catalpol reduced LPS induced BV2 immunoreactivity through NF-κB/NLRP3 pathways: an in Vitro and in silico study

Background: Ischemic Stroke (IS) stands as one of the primary cerebrovascular diseases profoundly linked with inflammation. In the context of neuroinflammation, an excessive activation of microglia has been observed. Consequently, regulating microglial activation emerges as a vital target for neuroinflammation treatment. Catalpol (CAT), a natural compound known for its anti-inflammatory properties, holds promise in this regard. However, its potential to modulate neuroinflammatory responses in the brain, especially on microglial cells, requires comprehensive exploration. Methods: In our study, we investigated into the potential anti-inflammatory effects of catalpol using lipopolysaccharide (LPS)-stimulated BV2 microglial cells as an experimental model. The production of nitric oxide (NO) by LPS-activated BV2 cells was quantified using the Griess reaction. Immunofluorescence was employed to measure glial cell activation markers. RT-qPCR was utilized to assess mRNA levels of various inflammatory markers. Western blot analysis examined protein expression in LPS-activated BV2 cells. NF-κB nuclear localization was detected by immunofluorescent staining. Additionally, molecular docking and molecular dynamics simulations (MDs) were conducted to explore the binding affinity of catalpol with key targets. Results: Catalpol effectively suppressed the production of nitric oxide (NO) induced by LPS and reduced the expression of microglial cell activation markers, including Iba-1. Furthermore, we observed that catalpol downregulated the mRNA expression of proinflammatory cytokines such as IL-6, TNF-α, and IL-1β, as well as key molecules involved in the NLRP3 inflammasome and NF-κB pathway, including NLRP3, NF-κB, caspase-1, and ASC. Our mechanistic investigations shed light on how catalpol operates against neuroinflammation. It was evident that catalpol significantly inhibited the phosphorylation of NF-κB and NLRP3 inflammasome activation, both of which serve as upstream regulators of the inflammatory cascade. Molecular docking and MDs showed strong binding interactions between catalpol and key targets such as NF-κB, NLRP3, and IL-1β. Conclusion: Our findings support the idea that catalpol holds the potential to alleviate neuroinflammation, and it is achieved by inhibiting the activation of NLRP3 inflammasome and NF-κB, ultimately leading to the downregulation of pro-inflammatory cytokines. Catalpol emerges as a promising candidate for the treatment of neuroinflammatory conditions.

Tanreqing injection inhibits dengue virus encephalitis by suppressing the activation of NLRP3 inflammasome

BACKGROUND

Encephalitis caused by dengue virus (DENV) is considered a manifestation of severe dengue. Tanreqing injection (TRQ) is a well-known Chinese patented medicine, which has been used to treat brain-related disorders by inhibiting inflammation. Nevertheless, the effects of TRQ on DENV encephalitis have not been studied. The aim of this study was to evaluate the effects of TRQ on DENV encephalitis and to explore its potential mechanisms.

METHODS

The cytotoxicity of TRQ was examined by MTT assay, and the anti-DENV activities of TRQ in BHK-21 baby hamster kidney fibroblast were evaluated through CCK-8 and plaque assays. The expression levels of NO, IL1B/IL-1β, TNFα and IL6 were measured by qRT‒PCR and ELISA in the BV2 murine microglial cell line. The inhibitory effects of TRQ on NLRP3 inflammasome activation in BV2 cells were examined by Western blotting, qRT‒PCR and ELISA. The effects of TRQ on HT22 mouse hippocampal neuronal cells were examined by CCK-8 assay, morphology observation and flow cytometry. Moreover, a DENV-infected ICR suckling mouse model was developed to investigate the protective role of TRQ in vivo.

RESULTS

TRQ decreased the release of NO, IL6, TNFα and IL1B from BV2 cells and inhibited the activation of NLRP3. The presence of the NLRP3 agonist nigericin reversed the anti-inflammatory activities of TRQ. Furthermore, TRQ inhibited the death of HT22 cells by decreasing IL1B in DENV-infected BV2 cells. In addition, TRQ significantly attenuated weight loss, reduced clinical scores and extended the survival in DENV-infected ICR suckling mice. Critically, TRQ ameliorated pathological changes in ICR suckling mice brain by inhibiting microglia and NLRP3 activation and decreasing the production of inflammatory factors and the number of dead neurons.

CONCLUSION

TRQ exerts potent inhibitory effects on dengue encephalitis in vitro and in vivo by reducing DENV-2-induced microglial activation and subsequently decreasing the inflammatory response, thereby protecting neurons. These findings demonstrate the potential of TRQ in the treatment of dengue encephalitis.

Regulatory mechanism of the six-method massage antipyretic process on lipopolysaccharide-induced fever in juvenile rabbits: A targeted metabolomics approach

Objective

To investigate the mechanism of the six-method massage antipyretic process (SMAP) and its influence on the body's metabolic state.

Methods

The random number table method was used to divide 24 New Zealand 2-month-old rabbits with qualified basal body temperature into a control group, model group and massage group (n = 8 per group). The model group and massage groups were injected with 0.5 μg/ml lipopolysaccharide (1 ml/kg) into the auricular vein, and the control group was injected with the same amount of normal saline at the same temperature. One hour after modelling, the massage group was given SMAP (opening Tianmen, pushing Kangong, rubbing Taiyang, rubbing Erhougaogu, clearing the Tianheshui and pushing the spine). The change of anal temperature 5 h after moulding was recorded to clarify the antipyretic effect.

Results

After modelling, the rectal temperature of the juvenile rabbits in the three groups increased. The rectal temperature of the model group was higher than that of the control group 5 h after modelling, and the rectal temperature of the massage group was lower than that of the model group (P < 0.05). The antipyretic mechanism is related to the regulation of the synthesis of phenylalanine, tyrosine and tryptophan, as well as the pentose phosphate pathway. Compared with the model group, the plasma interleukin (IL)-1, IL-6, interferon-gamma, toll-like receptor 4, nuclear factor κB, the mechanistic target of rapamycin complex 1, indoleamine 2,3-dioxygenase 1, aryl hydrocarbon receptor, liver aspartate transaminase (AST), alanine transaminase (ALT) and l-glutamate dehydrogenase (L-GLDH) expression in the massage group were significantly decreased (P < 0.05). Compared with the model group, the massage group had significantly reduced AST, ALT and L-GLDH expression in plasma (P < 0.05).

Conclusion

The mechanism of SMAP therapy is related to regulating the expression of peripheral inflammatory factors and metabolic pathways.

Gut Microbiota, Inflammatory Bowel Disease, and Cancer: The Role of Guardians of Innate Immunity

Inflammatory bowel diseases (IBDs) are characterized by a persistent low-grade inflammation that leads to an increased risk of colorectal cancer (CRC) development. Several factors are implicated in this pathogenetic pathway, such as innate and adaptive immunity, gut microbiota, environment, and xenobiotics. At the gut mucosa level, a complex interplay between the immune system and gut microbiota occurs; a disequilibrium between these two factors leads to an alteration in the gut permeability, called 'leaky gut'. Subsequently, an activation of several inflammatory pathways and an alteration of gut microbiota composition with a proliferation of pro-inflammatory bacteria, known as 'pathobionts', take place, leading to a further increase in inflammation. This narrative review provides an overview on the principal Pattern Recognition Receptors (PRRs), including Toll-like receptors (TLRs) and NOD-like receptors (NLRs), focusing on their recognition mechanisms, signaling pathways, and contributions to immune responses. We also report the genetic polymorphisms of TLRs and dysregulation of NLR signaling pathways that can influence immune regulation and contribute to the development and progression of inflammatory disease and cancer.

Leptin: A Heavyweight Player in Obesity-Related Cancers

Obesity, defined as the abnormal or excessive expansion of white adipose tissue, has reached pandemic proportions and is recognized as an important health concern since it is a common root for several comorbidities, including malignancies. Indeed, the current knowledge of the white adipose tissue, which shifts its role from an energy storage tissue to an important endocrine and metabolic organ, has opened up new avenues for the discovery of obesity's effects on tumor biology. In this review, we will report the epidemiological studies concerning the strong impact of obesity in several types of cancer and describe the mechanisms underlying the heterotypic signals between cancer cell lines and adipocytes, with particular emphasis on inflammation, the insulin/IGF-1 axis, and adipokines. Among the adipokines, we will further describe the in vitro, in vivo, and clinical data concerning the role of leptin, recognized as one of the most important mediators of obesity-associated cancers. In fact, leptin physiologically regulates energy metabolism, appetite, and reproduction, and several studies have also described the role of leptin in affecting cancer development and progression. Finally, we will summarize the newest pharmacological strategies aimed at mitigating the protumorigenic effects of leptin, underlining their mechanisms of action.

Activation of Inflammasome during Bluetongue Virus Infection

Bluetongue virus (BTV), a double-stranded RNA virus belonging to the Sedoreoviridae family, provokes an economically important disease in ruminants. In this study, we show that the production of activated caspase-1 and interleukin 1 beta (IL-1β) is induced in BTV-infected cells. This response seems to require virus replication since a UV-inactivated virus is unable to activate this pathway. In NLRP3^-/- cells, BTV could not trigger further IL-1β synthesis, indicating that it occurs through NLRP3 inflammasome activation. Interestingly, we observed differential activation levels in bovine endothelial cells depending on the tissue origin. In particular, inflammasome activation was stronger in umbilical cord cells, suggesting that these cells are more prone to induce the inflammasome upon BTV infection. Finally, the strength of the inflammasome activation also depends on the BTV strain, which points to the importance of viral origin in inflammasome modulation. This work reports the crucial role of BTV in the activation of the NLRP3 inflammasome and further shows that this activation relies on BTV replication, strains, and cell types, thus providing new insights into BTV pathogenesis.

Mechanistic and therapeutic role of Drp1 in the pathogenesis of stroke

Stroke had emerged as one of the leading causes of death and long-term disability across the globe. Emerging evidence suggests a significant increase in the incidence of stroke with age, which is further expected to increase dramatically owing to an ever-expanding elderly population. The current situation imposes a significant burden on the healthcare system and requires a deeper understanding of the underlying mechanisms and development of novel interventions. It is well established that mitochondrial dysfunction plays a pivotal role in the onset of stroke. Dynamin-related protein 1 (Drp1), is a key regulator of mitochondria fission, and plays a crucial role during the pathogenesis of stroke. Drp1 protein levels significantly increase after stroke potentially in a p38 mitogen-activated protein kinases (MAPK) dependent manner. Protein phosphatase 2A (PP2A) facilitate mitochondrial fission and cell death by dephosphorylating the mitochondrial fission enzyme Drp1 at the inhibitory phosphorylation site serine 637. Outer mitochondrial membrane A-Kinase Anchoring Proteins 1 (AKAP 1) and protein kinase A complex (PKA) complex inhibits Drp1-dependent mitochondrial fission by phosphorylating serine 637. Drp1 activation promotes the release of cytochrome C from mitochondria and therefore leads to apoptosis. In addition, Drp1 activation inhibits mitochondrial glutathione dependent free radical scavenging, which further enhances the ROS level and exacerbate mitochondrial dysfunction. Drp1 translocate p53 to mitochondrial membrane and leads to mitochondria-related necrosis. The current review article discusses the possible mechanistic pathways by which Drp1 can influence the pathogenesis of stroke. Besides, it will describe various inhibitors for Drp1 and their potential role as therapeutics for stroke in the future.

Thymosin Beta 4 Inhibits LPS and ATP-Induced Hepatic Stellate Cells via the Regulation of Multiple Signaling Pathways

Risk signals are characteristic of many common inflammatory diseases and can function to activate nucleotide-binding oligomerization (NLR) family pyrin domain-containing 3 (NLRP3), the innate immune signal receptor in cytoplasm. The NLRP3 inflammasome plays an important role in the development of liver fibrosis. Activated NLRP3 nucleates the assembly of inflammasomes, leading to the secretion of interleukin (IL)-1β and IL-18, the activation of caspase-1, and the initiation of the inflammatory process. Therefore, it is essential to inhibit the activation of the NLRP3 inflammasome, which plays a vital role in the immune response and in initiating inflammation. RAW 264.7 and LX-2 cells were primed with lipopolysaccharide (LPS) for 4 h and subsequently stimulated for 30 min with 5 mM of adenosine 5'-triphosphate (ATP) to activate the NLRP3 inflammasome. Thymosin beta 4 (Tβ4) was supplemented to RAW264.7 and LX-2 cells 30 min before ATP was added. As a result, we investigated the effects of Tβ4 on the NLRP3 inflammasome. Tβ4 prevented LPS-induced NLRP3 priming by inhibiting NF-kB and JNK/p38 MAPK expression and the LPS and ATP-induced production of reactive oxygen species. Moreover, Tβ4 induced autophagy by controlling autophagy markers (LC3A/B and p62) through the inhibition of the PI3K/AKT/mTOR pathway. LPS combined with ATP significantly increased thee protein expression of inflammatory mediators and NLRP3 inflammasome markers. These events were remarkably suppressed by Tβ4. In conclusion, Tβ4 attenuated NLRP3 inflammasomes by inhibiting NLRP3 inflammasome-related proteins (NLRP3, ASC, IL-1β, and caspase-1). Our results indicate that Tβ4 attenuated the NLRP3 inflammasome through multiple signaling pathway regulations in macrophage and hepatic stellate cells. Therefore, based on the above findings, it is hypothesized that Tβ4 could be a potential inflammatory therapeutic agent targeting the NLRP3 inflammasome in hepatic fibrosis regulation.

Effect of matrine in MAC-T cells and their transcriptome analysis: A basic study

Matrine, an alkaloid derived from herbal medicine, has a wide range of biological activities, including antibacterial. Matrine was toxic to multiple cells at high concentrations. Bovine mammary epithelial cells (MAC-T) could be used as model cells for cow breast. Matrine was a feasible option to replace antibiotics in the prevention or treatment of mastitis against the background of prohibiting antibiotics, but the safe concentration of matrine on MAC-T cells and the mechanism of action for matrine at different concentrations were still unclear. In this study, different concentrations of matrine (0.5, 1, 1.5, 2, 2.5 and 3 mg/mL) were used to treat MAC-T cells for various time periods (4, 8, 12, 16 and 24 h) and measure their lactic dehydrogenase (LDH). And then the optimal doses (2 mg/mL) were chosen to detect the apoptosis at various time periods by flow cytometry and transcriptome analysis was performed between the control and 2 mg/mL matrine-treated MAC-T cells for 8 hours. The results showed that matrine was not cytotoxic at 0.5 mg/mL, but it was cytotoxic at 1~3 mg/mL. In addition, matrine induced apoptosis in MAC-T cells at 2 mg/mL and the proportion of apoptosis cells increases with time by flow cytometry. RNA-seq analysis identified 1645 DEGs, 676 of which were expressed up-regulated and 969 were expressed down-regulated. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated the following pathways were linked to matrine-induced toxicity and apoptosis, including cytokine-cytokine receptor interaction pathway, viral protein interaction with cytokine and cytokine receptor, P53 and PPAR pathway. We found 7 DEGs associated with matrine toxicity and apoptosis. This study would provide a basis for the safety of matrine in the prevention or treatment of mastitis.

Mesangial cell: A hub in lupus nephritis

Lupus nephritis (LN) is a severe renal disease caused by the massive deposition of the immune complexes (ICs) in renal tissue, acting as one of the significant organ manifestations of systemic lupus erythematosus (SLE) and a substantial cause of death in clinical patients. As mesangium is one of the primary sites for IC deposition, mesangial cells (MCs) constantly undergo severe damage, resulting in excessive proliferation and increased extracellular matrix (ECM) production. In addition to playing a role in organizational structure, MCs are closely related to in situ immunomodulation by phagocytosis, antigen-presenting function, and inflammatory effects, aberrantly participating in the tissue-resident immune responses and leading to immune-mediated renal lesions. Notably, such renal-resident immune responses drive a second wave of MC damage, accelerating the development of LN. This review summarized the damage mechanisms and the in situ immune regulation of MCs in LN, facilitating the current drug research for exploring clinical treatment strategies.

Discovery of bakuchiol as an AIM2 inflammasome activator and cause of hepatotoxicity

ETHNOPHARMACOLOGICAL RELEVANCE

Psoralea corylifolia (P. corylifolia Linn.) is a traditional Chinese medicinal plant that exhibits significant aphrodisiac, diuretic, and anti-rheumatic effects. However, it has been reported to cause hepatic injury, but the precise mechanisms remain unclear.

AIM OF THE STUDY

To evaluate the safety and risk of P. corylifolia and to elucidate the underlying mechanisms of drug-induced liver injury.

MATERIALS AND METHODS

Western blotting, enzyme-linked immunosorbent assay (ELISA), immunofluorescence, quantitative polymerase chain reaction (Q-PCR), and flow cytometry were used to explore the effect of bakuchiol (Bak), one of the most abundant and biologically active components of P. corylifolia, on the AIM2 inflammasome activation and the underlying mechanism. Furthermore, we used the lipopolysaccharides (LPS)-induced drug-induced liver injury (DILI) susceptible mice model to study the Bak-mediated hepatotoxicity.

RESULTS

Bak induced the maturation of caspase-1 P20, and significantly increased the expression of IL-1β and TNF-α (P < 0.0001) compared with the control group. Moreover, compared to the Bak group, knockdown of AIM2 inhibited Bak-induced caspase-1 maturation and significantly decreased the production of IL-1β and TNF-α, but knockout of NLRP3 had no effect. Mechanistically, Bak-induced AIM2 inflammasome activation is involved in mitochondrial damage, mitochondrial DNA (mtDNA) release, and subsequent recognition of cytosolic mtDNA. Our in vivo data showed that co-exposure to LPS and non-hepatotoxic doses of Bak significantly increased the levels of ALT, AST, IL-1β, TNF-α, and IL-18, indicating that Bak can induce severe liver inflammation (P < 0.005).

CONCLUSIONS

The result shows that Bak activates the AIM2 inflammasome by inducing mitochondrial damage to release mtDNA, and subsequently binds to the AIM2 receptor, indicating that Bak may be a risk factor for P. corylifolia-induced hepatic injury.

Innate Immune Response and Inflammasome Activation During SARS-CoV-2 Infection

The novel coronavirus SARS-CoV-2, responsible for the COVID-19 outbreak, has become a pandemic threatening millions of lives worldwide. Recently, several vaccine candidates and drugs have shown promising effects in preventing or treating COVID-19, but due to the development of mutant strains through rapid viral evolution, urgent investigations are warranted in order to develop preventive measures and further improve current vaccine candidates. Positive-sense-single-stranded RNA viruses comprise many (re)emerging human pathogens that pose a public health problem. Our innate immune system and, in particular, the interferon response form an important first line of defense against these viruses. Flexibility in the genome aids the virus to develop multiple strategies to evade the innate immune response and efficiently promotes their replication and infective capacity. This review will focus on the innate immune response to SARS-CoV-2 infection and the virus' evasion of the innate immune system by escaping recognition or inhibiting the production of an antiviral state. Since interferons have been implicated in inflammatory diseases and immunopathology along with their protective role in infection, antagonizing the immune response may have an ambiguous effect on the clinical outcome of the viral disease. This pathology is characterized by intense, rapid stimulation of the innate immune response that triggers activation of the Nod-like receptor family, pyrin-domain-containing 3 (NLRP3) inflammasome pathway, and release of its products including the pro-inflammatory cytokines IL-6, IL-18, and IL-1β. This predictive view may aid in designing an immune intervention or preventive vaccine for COVID-19 in the near future.

NLRP3: Role in ischemia/reperfusion injuries

NLR family pyrin domain containing 3 (NLRP3) is expressed in immune cells, especially in dendritic cells and macrophages and acts as a constituent of the inflammasome. This protein acts as a pattern recognition receptor identifying pathogen-associated molecular patterns. In addition to recognition of pathogen-associated molecular patterns, it recognizes damage-associated molecular patterns. Triggering of NLRP3 inflammasome by molecules ATP released from injured cells results in the activation of the inflammatory cytokines IL-1β and IL-18. Abnormal activation of NLRP3 inflammasome has been demonstrated to stimulate inflammatory or metabolic diseases. Thus, NLRP3 is regarded as a proper target for decreasing activity of NLRP3 inflammasome. Recent studies have also shown abnormal activity of NLRP3 in ischemia/reperfusion (I/R) injuries. In the current review, we have focused on the role of this protein in I/R injuries in the gastrointestinal, neurovascular and cardiovascular systems.

Reactive oxygen species-dependent-NLRP3 inflammasome activation in human neutrophils induced by l-amino acid oxidase derived from Calloselasma rhodostoma venom

l-Amino acid oxidase isolated from Calloselasma rhodostoma (Cr-LAAO) snake venom is a potent stimulus for neutrophil activation and production of inflammatory mediators, contributing to local inflammatory effects in victims of envenoming. Cr-LAAO triggered the activation of nicotinamide adenine dinucleotide phosphatase (NADPH) oxidase complex and protein kinase C (PKC)-α signaling protein for reactive oxygen species (ROS) production. This study aims to evaluate the ROS participation in the NLRP3 inflammasome complex activation in human neutrophil. Human neutrophils were isolated and stimulated for 1 or 2 h with RPMI (negative control), LPS (1 μg/mL, positive control) or Cr-LAAO (50 μg/mL). The neutrophil transcriptome was examined using the microarray technique, and RT-qPCR for confirmation of gene expression. Immunofluorescence assays for NLRP3, caspase-1, IL-1β and GSDMD proteins was performed by Western blot in the presence and/or absence of Apocynin, an inhibitor of NADPH oxidase. IL-1β release was also detected in the presence and/or absence of NLRP3, caspase-1 and NADPH oxidase inhibitors. Results showed that Cr-LAAO upregulated the expression of genes that participate in the NADPH oxidase complex formation and inflammasome assembly. NLRP3 was activated and accumulated in the cytosol forming punctas, indicating its activation. Gasdermin D was not cleaved but lactate dehydrogenase was released. Furthermore, ROS inhibition decreased the expression of NLRP3 inflammasome complex proteins, as observed by protein expression in the presence and/or absence of apocynin, an NADPH oxidase inhibitor. IL-1β was also released, and pharmacological inhibition of NLRP3, caspase-1, and ROS reduced the amount of released cytokine. This is the first report demonstrating the activation of the NLRP3 inflammasome complex via ROS generation by Cr-LAAO, which may lead to the development of local inflammatory effects observed in snakebite victims.

NOD1, NOD2, and NLRC5 Receptors in Antiviral and Antimycobacterial Immunity

The innate immune system recognizes pathogen-associated molecular motifs through pattern recognition receptors (PRRs) that induce inflammasome assembly in macrophages and trigger signal transduction pathways, thereby leading to the transcription of inflammatory cytokine genes. Nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) represent a family of cytosolic PRRs involved in the detection of intracellular pathogens such as mycobacteria or viruses. In this review, we discuss the role of NOD1, NOD2, and NLRC5 receptors in regulating antiviral and antimycobacterial immune responses by providing insight into molecular mechanisms as well as their potential health and disease implications.

Inhibition of miR-423-5p Exerts Neuroprotective Effects in an Experimental Rat Model of Cerebral Ischemia/Reperfusion Injury

MicroRNAs (miRNAs) are widely acknowledged to play a unique role in cerebrovascular disease. This research investigates the function of microRNAs in ischemic stroke via a middle cerebral artery occlusion (MCAO) model. Four differentially expressed microRNAs in rat brains were identified by bioinformatics analysis, and qRT-PCR showed that miR-423-5p exhibited the highest expression in cerebral ischemia/reperfusion injury in rats, with peak levels observed at 24 hours. After microRNA inhibitors and mimics were administrated in the rat model of MCAO, the neurological scores and brain water content were detected, and triphenyltetrazolium chloride (TTC), Hematoxylin and Eosin (H&E), and Nissl staining were conducted to explore the influence of miR-423-5p on ischemic stroke. Subsequently, western blot, ELISA, MPO, TUNEL and commercial assay kits were applied to assess the influence of miR-423-5p on NLRP3 inflammasome, apoptosis, and oxidative stress levels in ischemic penumbra tissue. The results showed that miR-423-5p knockdown could effectively improve neurological indicators, such as cerebral infarct volume, brain water content, neurological scores, and nerve tissue damage, and inhibit the NLRP3 inflammasome, apoptosis, and oxidative stress. In contrast, the miR-423-5p mimic yielded opposite results. In conclusion, inhibition of miR-423-5p expression could effectively attenuate ischemic stroke and might be considered a promising target for stroke.

Assessing the suitability of long non-coding RNAs as therapeutic targets and biomarkers in SARS-CoV-2 infection

Long non-coding RNAs (lncRNAs) are RNA transcripts that are over 200 nucleotides and rarely encode proteins or peptides. They regulate gene expression and protein activities and are heavily involved in many cellular processes such as cytokine secretion in respond to viral infection. In severe COVID-19 cases, hyperactivation of the immune system may cause an abnormally sharp increase in pro-inflammatory cytokines, known as cytokine release syndrome (CRS), which leads to severe tissue damage or even organ failure, raising COVID-19 mortality rate. In this review, we assessed the correlation between lncRNAs expression and cytokine release syndrome by comparing lncRNA profiles between COVID-19 patients and health controls, as well as between severe and non-severe cases. We also discussed the role of lncRNAs in CRS contributors and showed that the lncRNA profiles display consistency with patients’ clinic symptoms, thus suggesting the potential of lncRNAs as drug targets or biomarkers in COVID-19 treatment.

The relationship among avian influenza, gut microbiota and chicken immunity: An updated overview

The alimentary tract in chickens plays a crucial role in immune cell formation and immune challenges, which regulate intestinal flora and sustain extra-intestinal immunity. The interaction between pathogenic microorganisms and the host commensal microbiota as well as the variety and integrity of gut microbiota play a vital role in health and disease conditions. Thus, several studies have highlighted the importance of gut microbiota in developing immunity against viral infections in chickens. The gut microbiota (such as different species of Lactobacillus, Blautia Bifidobacterium, Faecalibacterium, Clostridium XlVa, and members of firmicutes) encounters different pathogens through different mechanisms. The digestive tract is a highly reactive environment, and infectious microorganisms can disturb its homeostasis, resulting in dysbiosis and mucosal infections. Avian influenza viruses (AIV) are highly infectious zoonotic viruses that lead to severe economic losses and pose a threat to the poultry industry worldwide. AIV is a challenging virus that affects gut integrity, disrupts microbial homeostasis and induces inflammatory damage in the intestinal mucosa. H9N2 AIV infection elevates the expression of proinflammatory cytokines, such as interferon (IFN-γ and IFNα) and interleukins (IL-17A and IL-22), and increases the proliferation of members of proteobacteria, particularly Escherichia coli. On the contrary, it decreases the proliferation of certain beneficial bacteria, such as Enterococcus, Lactobacillus and other probiotic microorganisms. In addition, H9N2 AIV decreases the expression of primary gel-forming mucin, endogenous trefoil factor family peptides and tight junction proteins (ZO-1, claudin 3, and occludin), resulting in severe intestinal damage. This review highlights the relationship among AIV, gut microbiota and immunity in chicken.

Peste Des Petits Ruminants Virus N Protein Is a Critical Proinflammation Factor That Promotes MyD88 and NLRP3 Complex Assembly

Inflammatory responses play a central role in host defense against invading pathogens. Peste des petits ruminants virus (PPRV) causes highly contagious acute or subacute disease of small ruminants. However, the precise mechanism by which PPRV regulates inflammatory responses remains unknown. Here, we revealed a novel mechanism by which PPRV induces inflammation. Our study showed that PPRV induced the secretion of interleukin 1β (IL-1β) by activating the NF-κB signaling pathway and the NLRP3 inflammasome. Moreover, PPRV replication and protein synthesis were essential for NLRP3 inflammasome activation. Importantly, PPRV N protein promoted NF-κB signaling pathway and NLRP3 inflammasome via direct binding of MyD88 and NLPR3, respectively, and induced caspase-1 cleavage and IL-1β maturation. Biochemically, N protein interacted with MyD88 to potentiate the assembly of MyD88 complex and interacted with NLPR3 to facilitate NLRP3 inflammasome complex assembly by forming an N-NLRP3-ASC ring-like structure, leading to IL-1β secretion. These findings demonstrate a new function of PPRV N protein as an important proinflammation factor and identify a novel underlying mechanism modulating inflammasome assembly and function induced by PPRV. IMPORTANCE An important part of the innate immune response is the activation of NF-κB signaling pathway and NLPR3 inflammasome, which is induced upon exposure to pathogens. Peste des petits ruminants virus (PPRV) is a highly contagious virus causing fever, stomatitis, and pneumoenteritis in goats by inducing many proinflammatory cytokines. Although the NF-κB signaling pathway and NLRP3 inflammasome play an important role in regulating host immunity and viral infection, the precise mechanism by which PPRV regulates inflammatory responses remains unknown. This study demonstrates that PPRV induces inflammatory responses. Mechanistically, PPRV N protein facilitates the MyD88 complex assembly by directly binding to MyD88 and promotes the NLRP3 inflammasome complex assembly by directly binding to NLRP3 to form ring-like structures of N-NLRP3-ASC. These findings provide insights into the prevention and treatment of PPRV infection.

COVID-19 and Retinal Degenerative Diseases: Promising link “Kaempferol”

Coronavirus disease (COVID-19) outbreak has caused unprecedented global disruption since 2020. Approximately 238 million people are affected worldwide where the elderly succumb to mortality. Post-COVID syndrome and its side effects have popped up with several health hazards, such as macular degeneration and vision loss. It thus necessitates better medical care and management of our dietary practices. Natural flavonoids have been included in traditional medicine and have also been used safely against COVID-19 and several other diseases. Kaempferol is an essential flavonoid that has been demonstrated to influence several vital cellular signaling pathways involved in apoptosis, angiogenesis, inflammation, and autophagy. In this review, we emphasize the plausible regulatory effects of Kaempferol on hallmarks of COVID-19 and macular degeneration.

LncRNA Neat1 promotes the macrophage inflammatory response and acts as a therapeutic target in titanium particle-induced osteolysis

Aseptic loosening (AL), secondary to particle-caused periprosthetic osteolysis, is one of the main reasons of artificial joint failure. Suppressing the macrophage inflammatory response caused by wear particles extends the life of prosthesis, and the long noncoding RNAs (lncRNAs) may play a predominant part in it. Here, titanium particles' (TiPs') stimulation increases both the cytoplasmic and nuclear levels of lncRNA Neat1 in bone marrow derived macrophages (BMDMs), which further induces the inflammatory response. Mechanically, Neat1 facilitates Bruton's tyrosine kinase (BTK) transcription by reducing the transcriptional factor KLF4, which further activates the NF-κB pathway, NLRP3 inflammation, and M1 polarization in BMDMs. Cytoplasmic Neat1 also works as an miRNA sponge in miR-188-5p-regulated BTK expression in the post-transcriptional stage. In vivo, Neat1 downregulation can reduce the TiP-induced pro-inflammatory factors and reverse the osteolysis induced by BTK overexpression. In addition, the PLGA-based microparticles loaded with si-Neat1 are developed for the treatment of the mouse calvarial osteolysis model via local injection, presenting satisfactory anti-osteolysis efficacy. These findings indicate that Neat1 is a key regulator of AL. STATEMENT OF SIGNIFICANCE: Due to released particles, aseptic loosening (AL) is the most common reason for prosthesis failure and surgical revision and represents a substantial economic burden worldwide. Herein, we reported that lncRNA Neat1 is a key regulator in regulating wear particles-induced osteolysis by activating NF-κB pathway, NLRP3 inflammation and M1 polarization via BTK, and the underlying mechanisms of Neat1-BTK interaction were further portrayed. For potential clinical application, the microparticles are developed for effective si-Neat1 delivery, leading to a dramatically enhanced effect for the treatment of osteolysis, which might be a novel strategy to extend the life of the implant.

Targeting macrophage TFEB-14-3-3 epsilon Interface by naringenin inhibits abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a lethal cardiovascular disease, and there is no proven drug treatment for this condition. In this study, by using the Connectivity Map (CMap) approach, we explored naringenin, a naturally occurring citrus flavonoid, as a putative agent for inhibiting AAA. We then validated the prediction with two independent mouse models of AAA, calcium phosphate (CaPO₄)-induced C57BL/6J mice and angiotensin II-infused ApoE^−/− mice. Naringenin effectively blocked the formation of AAAs and the progression of established AAAs. Transcription factor EB (TFEB) is the master regulator of lysosome biogenesis. Intriguingly, the protective role of naringenin on AAA was abolished by macrophage-specific TFEB depletion in mice. Unbiased interactomics, combined with isothermal titration calorimetry (ITC) and cellular thermal shift assays (CETSAs), further revealed that naringenin is directly bound to 14-3-3 epsilon blocked the TFEB-14-3-3 epsilon interaction, and therefore promoted TFEB nuclear translocation and activation. On one hand, naringenin activated lysosome-dependent inhibition of the NLRP3 inflammasome and repressed aneurysmal inflammation. On the other hand, naringenin induced TFEB-dependent transcriptional activation of GATA3, IRF4, and STAT6 and therefore promoted reparative M2 macrophage polarization. In summary, naturally derived naringenin or macrophage TFEB activation shows promising efficacy for the treatment of AAA.

Promising Therapeutic Candidate for Myocardial Ischemia/Reperfusion Injury: What Are the Possible Mechanisms and Roles of Phytochemicals?

Percutaneous coronary intervention (PCI) is one of the most effective reperfusion strategies for acute myocardial infarction (AMI) despite myocardial ischemia/reperfusion (I/R) injury, causing one of the causes of most cardiomyocyte injuries and deaths. The pathological processes of myocardial I/R injury include apoptosis, autophagy, and irreversible cell death caused by calcium overload, oxidative stress, and inflammation. Eventually, myocardial I/R injury causes a spike of further cardiomyocyte injury that contributes to final infarct size (IS) and bound with hospitalization of heart failure as well as all-cause mortality within the following 12 months. Therefore, the addition of adjuvant intervention to improve myocardial salvage and cardiac function calls for further investigation. Phytochemicals are non-nutritive bioactive secondary compounds abundantly found in Chinese herbal medicine. Great effort has been put into phytochemicals because they are often in line with the expectations to improve myocardial I/R injury without compromising the clinical efficacy or to even produce synergy. We summarized the previous efforts, briefly outlined the mechanism of myocardial I/R injury, and focused on exploring the cardioprotective effects and potential mechanisms of all phytochemical types that have been investigated under myocardial I/R injury. Phytochemicals deserve to be utilized as promising therapeutic candidates for further development and research on combating myocardial I/R injury. Nevertheless, more studies are needed to provide a better understanding of the mechanism of myocardial I/R injury treatment using phytochemicals and possible side effects associated with this approach.

Glibenclamide Alleviates LPS-Induced Acute Lung Injury through NLRP3 Inflammasome Signaling Pathway

Glibenclamide displays an anti-inflammatory response in various pulmonary diseases, but its exact role in lipopolysaccharide- (LPS-) induced acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) remains unknown. Herein, we aimed to explore the effect of glibenclamide in vivo and in vitro on the development of LPS-induced ALI in a mouse model. LPS stimulation resulted in increases in lung injury score, wet/dry ratio, and capillary permeability in lungs, as well as in total protein concentration, inflammatory cells, and inflammatory cytokines including IL-1β, IL-18 in bronchoalveolar lavage fluid (BALF), and lung tissues, whereas glibenclamide treatment reduced these changes. Meanwhile, the increased proteins of NLRP3 and Caspase-1/p20 after LPS instillation in lungs were downregulated by glibenclamide. Similarly, in vitro experiments also found that glibenclamide administration inhibited the LPS-induced upregulations in cytokine secretions of IL-1β and IL-18, as well as in the expression of components in NLRP3 inflammasome in mouse peritoneal macrophages. Of note, glibenclamide had no effect on the secretion of TNF-α in vivo nor in vitro, implicating that its anti-inflammatory effect is relatively specific to NLRP3 inflammasome. In conclusion, glibenclamide alleviates the development of LPS-induced ALI in a mouse model via inhibiting the NLRP3/Caspase-1/IL-1β signaling pathway, which might provide a new strategy for the treatment of LPS-induced ALI.

Melatonin alleviates lipopolysaccharide (LPS) / adenosine triphosphate (ATP)-induced pyroptosis in rat alveolar Type II cells (RLE-6TN) through nuclear factor erythroid 2-related factor 2 (Nrf2)-driven reactive oxygen species (ROS) downregulation

Pyroptosis has pivotal parts within disease development, rendering this attractive mechanism for novel therapeutics. This investigation aimed at analyzing melatonin roles within pyroptosis together with related mechanistics. RLE-6TN cultures were exposed to varying LPS doses for 4.5 h followed by concomitant culturing in the presence of ATP (5 mM) for 0.5 h to induce injury, and the roles of melatonin, N-Acety-L-cysteine (NAC - a ROS scavenger), ML385 (specific Nrf2 inhibitor) were examined. Apoptosis analysis was performed through lactate dehydrogenase (LDH) activity assays, together with propidium iodide (PI) stain-assay. Intracellular ROS were quantified through 2, 7-dichlorodihydrofluorescein diacetate (DCFH-DA). Pyrolysis-associated proteins, such as nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3), apoptosis-associated speck-like protein containing a CARD (ASC), cysteine aspartate-specific protease-1 P20 (Caspase-1 P20), gasdermin D-N (GSDMD-N), and mature interleukin-1β (IL-1β), were identified through Western blotting. Dataset outcomes demonstrated LPS/ATP induce RLE-6TN cell pyroptosis, while melatonin alleviated this phenomenon, visualized through increased cell survival rate, reduction of LDH discharge and PI⁺ cellular count. Moreover, melatonin effectively reduced NLRP3 inflammasome triggering in RLE-6TN cells. Meanwhile, this study demonstrated melatonin thwarting over NLRP3 inflammasome triggering was depending on ROS. In addition, this study found that melatonin activated Nrf2/Heme Oxygenase-1 (HO-1) pathway, with pyroptotic-inhibiting function of melatonin was reverted through a bespoke Nrf2-inhibitor and siNrf2. In summary, this study concluded that melatonin prevents RLE-6TN cellular pyroptosis through Nrf2-triggered ROS downregulation.

Itaconate inhibits ferroptosis of macrophage via Nrf2 pathways against sepsis-induced acute lung injury

Itaconate, a metabolite produced during inflammatory macrophage activation, has been extensively described to be involved in immunoregulation, oxidative stress, and lipid peroxidation. As a form of iron and lipid hydroperoxide-dependent regulated cell death, ferroptosis plays a critical role in sepsis-induced acute lung injury (ALI). However, the relationship between itaconate and ferroptosis remains unclear. This study aims to explore the regulatory role of itaconate on ferroptosis in sepsis-induced ALI. In in vivo experiments, mice were injected with LPS (10 mg/kg) for 12 h to generate experimental sepsis models. Differential gene expression analysis indicated that genes associated with ferroptosis existed significant differences after itaconate pretreatment. 4-octyl itaconate (4-OI), a cell-permeable derivative of endogenous itaconate, can significantly alleviate lung injury, increase LPS-induced levels of glutathione peroxidase 4 (GPX4) and reduce prostaglandin-endoperoxide synthase 2 (PTGS2), malonaldehyde (MDA), and lipid ROS. In vitro experiments showed that both 4-OI and ferrostatin-1 inhibited LPS-induced lipid peroxidation and injury of THP-1 macrophage. Mechanistically, we identified that 4-OI inhibited the GPX4-dependent lipid peroxidation through increased accumulation and activation of Nrf2. The silence of Nrf2 abolished the inhibition of ferroptosis from 4-OI in THP-1 cells. Additionally, the protection of 4-OI for ALI was abolished in Nrf2-knockout mice. We concluded that ferroptosis was one of the critical mechanisms contributing to sepsis-induced ALI. Itaconate is promising as a therapeutic candidate against ALI through inhibiting ferroptosis.

Cancer and Covid-19: Collectively catastrophic

The Covid-19 pandemic has spread rapidly across the globe, resulting in more than 3 million deaths worldwide. The symptoms of Covid-19 are usually mild and non-specific, however in some cases patients may develop acute respiratory distress syndrome (ARDS) and systemic inflammation. Individuals with inflammatory or immunocompromising illnesses, such as cancer, are more susceptible to develop ARDS and have higher rates of mortality. This is mediated through an initial hyperstimulated immune response which results in elevated levels of pro-inflammatory cytokines and a subsequent cytokine storm. This potentiates positive feedback loops which are unable to be balanced by anti-inflammatory mediators. Therefore, elevated levels of IL-1β, as a result of NLRP3 inflammasome activation, as well as IL-6 and TNF-α amongst many others, contribute to the progression of various cancer types. Furthermore, Covid-19 progression is associated with the depletion of CD8+ and CD4+ T cells, B cell and natural killer cell numbers. Collectively, a Covid-19-dependent pro-inflammatory profile and immune suppression promotes the optimal microenvironment for tumourigenesis, initiation and immune evasion of malignant cells, tumour progression and metastasis as well as cancer recurrence. There are, however, therapeutic windows of opportunity that may combat both Covid-19 and cancer to improve patient outcomes.

The role of itaconate in host defense and inflammation

Macrophages exposed to inflammatory stimuli including LPS undergo metabolic reprogramming to facilitate macrophage effector function. This metabolic reprogramming supports phagocytic function, cytokine release, and ROS production that are critical to protective inflammatory responses. The Krebs cycle is a central metabolic pathway within all mammalian cell types. In activated macrophages, distinct breaks in the Krebs cycle regulate macrophage effector function through the accumulation of several metabolites that were recently shown to have signaling roles in immunity. One metabolite that accumulates in macrophages because of the disturbance in the Krebs cycle is itaconate, which is derived from cis-aconitate by the enzyme cis-aconitate decarboxylase (ACOD1), encoded by immunoresponsive gene 1 (Irg1). This Review focuses on itaconate’s emergence as a key immunometabolite with diverse roles in immunity and inflammation. These roles include inhibition of succinate dehydrogenase (which controls levels of succinate, a metabolite with multiple roles in inflammation), inhibition of glycolysis at multiple levels (which will limit inflammation), activation of the antiinflammatory transcription factors Nrf2 and ATF3, and inhibition of the NLRP3 inflammasome. Itaconate and its derivatives have antiinflammatory effects in preclinical models of sepsis, viral infections, psoriasis, gout, ischemia/reperfusion injury, and pulmonary fibrosis, pointing to possible itaconate-based therapeutics for a range of inflammatory diseases. This intriguing metabolite continues to yield fascinating insights into the role of metabolic reprogramming in host defense and inflammation.

Tibolone restrains neuroinflammation in mouse experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is an immune-mediated and degenerating disease in which myelin sheaths are damaged as a result of chronic progressive inflammation of the central nervous system. Tibolone [(7α,17α)-17-hydroxy-7-methyl-19-norpregn-5(10)-en-20-in-3-one], a synthetic estrogenic compound with tissue-specific actions and used for menopausal hormone therapy, shows neuroprotective and antioxidant properties both in vivo and in vitro. In the present study, we analyzed whether tibolone plays a therapeutic role in experimental autoimmune encephalomyelitis (EAE) mice, a commonly used model of MS. Female C57BL/6 mice were induced with the myelin oligodendrocyte glycoprotein MOG_35-55 and received s.c. tibolone (0.08 mg kg^-1 ) injection every other day from the day of induction until death on the acute phase of the disease. Reactive gliosis, Toll like receptor 4 (TLR4), high mobility group box protein 1 (HMGB1), inflammasome parameters, activated Akt levels and myelin were assessed by a real-time polymerase chain reaction, immunohistochemistry, and western blot analysis. Our findings indicated that, in the EAE spinal cord, tibolone reversed the astrocytic and microglial reaction, and reduced the hyperexpression of TLR4 and HMGB1, as well as NLR family pyrin domain containing 3-caspase 1-interleukin-1β inflammasome activation. At the same time, tibolone attenuated the Akt/nuclear factor kappa B pathway and limited the white matter demyelination area. Estrogen receptor expression was unaltered with tibolone treatment. Clinically, tibolone improved neurological symptoms without uterine compromise. Overall, our data suggest that tibolone may serve as a promising agent for the attenuation of MS-related inflammation.

Role of NLRP3 Inflammasome in Parkinson's Disease and Therapeutic Considerations

Parkinson's disease (PD) is the second most common neurodegenerative disease, with two main pathological features: misfolded α-synuclein protein accumulation and neurodegeneration. Inflammation has recently been identified as a contributor to a cascade of events that may aggravate PD pathology. Inflammasomes, a group of intracellular protein complexes, play an important role in innate immune responses to various diseases, including infection. In PD research, accumulating evidence suggests that α-synuclein aggregations may activate inflammasomes, particularly the nucleotide-binding oligomerization domain-leucine-rich repeat-pyrin domain-containing 3 (NLRP3) type, which exacerbates inflammation in the central nervous system by secreting proinflammatory cytokines like interleukin (IL)-18 and IL-1β. Afterward, activated NLRP3 triggers local microglia and astrocytes to release additional IL-1β. In turn, the activated inflammatory process may contribute to additional α-synuclein aggregation and cell loss. This review summarizes current research evidence on how the NLRP3 inflammasome contributes to PD pathogenesis, as well as potential therapeutic strategies targeting the NLRP3 inflammasome in PD.

Perspectives on electrochemical biosensing of COVID-19

Rapid detection of human coronavirus disease 2019, termed as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or COVID-19 infection, is urgently needed for containment strategy owing to its unprecedented spreading. Novel biosensors can be deployed in remote clinical settings without central facilities for infection screening. Electrochemical biosensors serve as analytical tools for rapid detection of viral structure proteins, mainly spike (S) and nucleocapsid (N) proteins, human immune responses, reactive oxygen species, viral ribonucleic acid, polymerase chain reaction by-products, and other potential biomarkers. The development of point-of-care testing devices is challenging due to the requirement of extensive validation, a time-consuming and expensive step. Together with specific biorecognition molecules, nanomaterial-based biosensors have emerged for the fast detection of early viral infections.

Novel organoselenides (NSAIDs-Se derivatives) protect against LPS-induced inflammation in microglia by targeting the NOX2/NLRP3 signaling pathway

Neuro-inflammation is an immune response of the central nervous system (CNS) to pathogens, and it is associated with a variety of neurodegenerative diseases. Microglial cells are the main category of macrophages in the CNS parenchyma, and they represent one of the most important cellular drivers and regulators of neuroinflammation. In this study, nine new organoselenium compounds based on the hybridization of nonsteroidal anti-inflammatory drugs (NSAIDs) skeleton and organoselenium motif (-SeCN and -SeCF3) were synthesized and their potential anti-neuroinflammatory effects were evaluated using LPS-induced BV2 mouse microglia. The cells were first treated with the organoselenium compounds and the extent of oxidative stress and inflammatory response of the cells was determined by measuring the levels of NO, ROS, IL-1β, and IL-18. Among the nine compounds, 1-39 and 1A-38 exhibited the most significant effect on oxidative stress and inflammatory response. Subsequent studies carried out with 1-39 and 1A-38 showed that both compounds could reduce the production of ROS in the cells, probably through down-regulating NOX2 and its downstream targets, including TXNIP (thioredoxin-interacting protein) and NLRP3 (NOD-like receptor protein 3). In addition, 1-39 and 1A-38 also suppressed the ability of the cells to secret IL-18 and IL-1β, which greatly dampened the response of the cells to LPS-induced inflammation. Our finding demonstrated that organoselenium compounds derived from NSAID might play an important role in the protection of brain microglia against inflammation-related neurodegenerative disease by potentially down-regulating the NOX2/NLRP3 signaling axis.

How cytosolic compartments play safeguard functions against neuroinflammation and cell death in cerebral ischemia

Ischemic stroke is the second leading cause of mortality and disability globally. Neuronal damage following ischemic stroke is rapid and irreversible, and eventually results in neuronal death. In addition to activation of cell death signaling, neuroinflammation is also considered as another pathogenesis that can occur within hours after cerebral ischemia. Under physiological conditions, subcellular organelles play a substantial role in neuronal functionality and viability. However, their functions can be remarkably perturbed under neurological disorders, particularly cerebral ischemia. Therefore, their biochemical and structural response has a determining role in the sequel of neuronal cells and the progression of disease. However, their effects on cell death and neuroinflammation, as major underlying mechanisms of ischemic stroke, are still not understood. This review aims to provide a comprehensive overview of the contribution of each organelle on these pathological processes after ischemic stroke.

Role of the inflammasome, gasdermin D, and pyroptosis in non-alcoholic fatty liver disease

Pyroptosis is a type of programmed cell death mediated by a multiprotein complex called the inflammasome through the pro-inflammatory activity of gasdermin D. This study aimed to recognize the final biological product that leads to pore formation in the cell membrane, lysis, pro-inflammatory cytokines release, and the establishment of an immune response. An exhaustive search engine investigation of an elevated immune response can induce a sustained inflammation that directly links this mechanism to non-alcoholic fatty liver disease and its progression to non-alcoholic steatohepatitis. Clinical studies and systematic reviews suggest that gasdermin D is a critical molecule between the immune response and the disease manifestation, which could be considered a therapeutic target for highly prevalent diseases characterized by presenting perpetuated inflammatory processes. Both basic and clinical research show evidence on the expression and regulation of the inflammasome-gasdermin D-pyroptosis trinomial for the progression of non-alcoholic fatty liver disease to non-alcoholic steatohepatitis.

NLRP3 inflammasomes are involved in the progression of postoperative cognitive dysfunction: from mechanism to treatment

Postoperative cognitive dysfunction (POCD) involves patient memory and learning decline after surgery. POCD not only presents challenges for postoperative nursing and recovery but may also cause permanent brain damage for patients, including children and the aged, with vulnerable central nervous systems. Its occurrence is mainly influenced by surgical trauma, anesthetics, and the health condition of the patient. There is a lack of imaging and experimental diagnosis; therefore, patients can only be diagnosed by clinical observation, which may underestimate the morbidity, resulting in decreased treatment efficacy. Except for symptomatic support therapy, there is a relative lack of effective drugs specific for the treatment of POCD, because the precise mechanism of POCD remains to be determined. One current hypothesis is that postoperative inflammation promotes the progression of POCD. Accumulating research has indicated that overactivation of NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasomes contribute to the POCD progression, suggesting that targeting NLRP3 inflammasomes may be an effective therapy to treat POCD. In this review, we summarize recent studies and systematically describe the pathogenesis, treatment progression, and potential treatment options of targeting NLRP3 inflammasomes in POCD patients.

Fisetin Inhibits NLRP3 Inflammasome by Suppressing TLR4/MD2-Mediated Mitochondrial ROS Production

Fisetin has numerous therapeutic properties, such as anti-inflammatory, antioxidative, and anticancer effects. However, the mechanism by which fisetin inhibits NLRP3 inflammasome remains unclear. In this study, we observed that fisetin bound to TLR4 and occluded the hydrophobic pocket of MD2, which in turn inhibited the binding of LPS to the TLR4/MD2 complex. This prevented the initiation of scaffold formation by the inhibition of MyD88/IRAK4 and subsequently downregulated the NF-κB signaling pathway. The result also demonstrated that fisetin downregulated the activation of the NLRP3 inflammasome induced by LPS and ATP (LPS/ATP) and the subsequent maturation of IL-1β. Fisetin also activated mitophagy and prevented the accumulation of damaged mitochondria and the excessive production of mitochondrial reactive oxygen species. The transient knockdown of p62 reversed the inhibitory activity of fisetin on the LPS/ATP-induced formation of the NLRP3 inflammasome. This indicated that fisetin induces p62-mediated mitophagy for eliminating damaged mitochondria. Recently, the existence of inflammasomes in non-mammalian species including zebrafish have been identified. Treatment of an LPS/ATP-stimulated zebrafish model with fisetin aided the recovery of the impaired heart rate, decreased the recruitment of macrophage to the brain, and gradually downregulated the expression of inflammasome-related genes. These results indicated that fisetin inhibited the TLR4/MD2-mediated activation of NLRP3 inflammasome by eliminating damaged mitochondria in a p62-dependent manner.

Beneficial Effects of Exogenous Ketogenic Supplements on Aging Processes and Age-Related Neurodegenerative Diseases

Life expectancy of humans has increased continuously up to the present days, but their health status (healthspan) was not enhanced by similar extent. To decrease enormous medical, economical and psychological burden that arise from this discrepancy, improvement of healthspan is needed that leads to delaying both aging processes and development of age-related diseases, thereby extending lifespan. Thus, development of new therapeutic tools to alleviate aging processes and related diseases and to increase life expectancy is a topic of increasing interest. It is widely accepted that ketosis (increased blood ketone body levels, e.g., β-hydroxybutyrate) can generate neuroprotective effects. Ketosis-evoked neuroprotective effects may lead to improvement in health status and delay both aging and the development of related diseases through improving mitochondrial function, antioxidant and anti-inflammatory effects, histone and non-histone acetylation, β-hydroxybutyrylation of histones, modulation of neurotransmitter systems and RNA functions. Administration of exogenous ketogenic supplements was proven to be an effective method to induce and maintain a healthy state of nutritional ketosis. Consequently, exogenous ketogenic supplements, such as ketone salts and ketone esters, may mitigate aging processes, delay the onset of age-associated diseases and extend lifespan through ketosis. The aim of this review is to summarize the main hallmarks of aging processes and certain signaling pathways in association with (putative) beneficial influences of exogenous ketogenic supplements-evoked ketosis on lifespan, aging processes, the most common age-related neurodegenerative diseases (Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis), as well as impaired learning and memory functions.

Redox Role of ROS and Inflammation in Pulmonary Diseases

Reactive oxygen species (ROS), either derived from exogenous sources or overproduced endogenously, can disrupt the body's antioxidant defenses leading to compromised redox homeostasis. The lungs are highly susceptible to ROS-mediated damage. Oxidative stress (OS) caused by this redox imbalance leads to the pathogenesis of multiple pulmonary diseases such as asthma, chronic obstructive pulmonary disease (COPD), and acute respiratory distress syndrome (ARDS). OS causes damage to important cellular components in terms of lipid peroxidation, protein oxidation, and DNA histone modification. Inflammation further enhances ROS production inducing changes in transcriptional factors which mediate cellular stress response pathways. This deviation from normal cell function contributes to the detrimental pathological characteristics often seen in pulmonary diseases. Although antioxidant therapies are feasible approaches in alleviating OS-related lung impairment, a comprehensive understanding of the updated role of ROS in pulmonary inflammation is vital for the development of optimal treatments. In this chapter, we review the major pulmonary diseases-including COPD, asthma, ARDS, COVID-19, and lung cancer-as well as their association with ROS.

The Role of NF-κB Triggered Inflammation in Cerebral Ischemia

Cerebral ischemia is a devastating disease that affects many people worldwide every year. The neurodegenerative damage as a consequence of oxygen and energy deprivation, to date, has no known effective treatment. The ischemic insult is followed by an inflammatory response that involves a complex interaction between inflammatory cells and molecules which play a role in the progression towards cell death. However, there is presently a matter of controversy over whether inflammation could either be involved in brain damage or be a necessary part of brain repair. The inflammatory response is triggered by inflammasomes, key multiprotein complexes that promote secretion of pro-inflammatory cytokines. An early event in post-ischemic brain tissue is the release of certain molecules and reactive oxygen species (ROS) from injured neurons which induce the expression of the nuclear factor-kappaB (NF-κB), a transcription factor involved in the activation of the inflammasome. There are conflicting observations related to the role of NF-κB. While some observe that NF-κB plays a damaging role, others suggest it to be neuroprotective in the context of cerebral ischemia, indicating the need for additional investigation. Here we discuss the dual role of the major inflammatory signaling pathways and provide a review of the latest research aiming to clarify the relationship between NF-κB mediated inflammation and neuronal death in cerebral ischemia.

Dimethyl Itaconate-Loaded Nanofibers Rewrite Macrophage Polarization, Reduce Inflammation, and Enhance Repair of Myocardic Infarction

Cellular metabolism plays a major role in the regulation of inflammation. The inflammatory macrophages undergo a wide-range of metabolic rewriting due to the production of significant amount of itaconate metabolite from cis-aconitate in the tricarboxylic acid cycle. This itaconate molecule has been recently described as a promising immunoregulator. However, its function and mode of action on macrophages and tissue repair and regeneration are yet unclear. Herein, the itaconate-derivative dimethyl itaconate (DMI) suppresses the IL-23/IL-17 inflammatory axis-associated genes and promotes antioxidant nuclear factor erythroid 2-related factor 2 target genes. The poly-ε-caprolactone (PCL)/DMI nanofibers implanted in mice initially maintain inflammation by suppressing anti-inflammatory activity and particular inflammation, while at later stage promotes anti-inflammatory activity for an appropriate tissue repair. Furthermore, the PCL/DMI nanofiber patches show an excellent myocardial protection by reducing infarct area and improving ventricular function via time-dependent regulation of myocardium-associated genes. This study unveils potential DMI macrophage modulatory functions in tissue microenvironment and macrophages rewriting for proper tissue repair.

The relationship of oleic acid/albumin molar ratio and clinical outcomes in leptospirosis

Human leptospirosis is an acute infectious zoonosis presenting specific lipid disorders. Previous in vitro studies showed both leptospira glycolipoprotein endotoxin, and high oleic acid levels were associated with Na/K-ATPase inhibition that is amplified by the reduction of circulating albumin levels. In this study, we aimed to investigate the relationship of oleic acid/albumin (OA/A) molar ratio and clinical outcomes in Leptospirosis. Through a prospective observational cohort study employing high-performance liquid chromatography (HPLC) we sequentially determined serum concentrations of nonesterified fatty acids (NEFA) and albumin in twenty-eight patients with severe leptospirosis since their hospital admission. Twenty patients recovered, and eight died. Data was distributed in two groups according to clinical outcomes. Oleic acid/albumin molar ratios (OA/A), initial samples, were higher than those in healthy donors. The ratio OA/A, however, persisted high in dying patients, whereas patients who survived had a reduction matching to healthy donors. Biochemical alterations suggest that cure is correlated to the reestablishment of the OA/A molar ratio, while fatal outcomes related to persisting OA/A imbalances. Analysis by receiver operating characteristic (ROC) showed the area under the curve of 0.864 and the cutoff value of 0.715 being associated with a high odds ratio. Lipid analysis from patients with leptospirosis had an acute high serum OA/A molar ratio, and sustained imbalance has a high odds ratio and strong correlation with mortality.

β-Glucan-induced reprogramming of human macrophages inhibits NLRP3 inflammasome activation in cryopyrinopathies

Exposure of mononuclear phagocytes to β-glucan, a naturally occurring polysaccharide, contributes to the induction of innate immune memory, which is associated with long-term epigenetic, metabolic, and functional reprogramming. Although previous studies have shown that innate immune memory induced by β-glucan confers protection against secondary infections, its impact on autoinflammatory diseases, associated with inflammasome activation and IL-1β secretion, remains poorly understood. In particular, whether β-glucan-induced long-term reprogramming affects inflammasome activation in human macrophages in the context of these diseases has not been explored. We found that NLRP3 inflammasome-mediated caspase-1 activation and subsequent IL-1β production were reduced in β-glucan-reprogrammed macrophages. β-Glucan acted upstream of the NLRP3 inflammasome by preventing potassium (K+) efflux, mitochondrial ROS (mtROS) generation, and, ultimately, apoptosis-associated speck-like protein containing a CARD (ASC) oligomerization and speck formation. Importantly, β-glucan-induced memory in macrophages resulted in a remarkable attenuation of IL-1β secretion and caspase-1 activation in patients with an NLRP3-associated autoinflammatory disease, cryopyrin-associated periodic syndromes (CAPS). Our findings demonstrate that β-glucan-induced innate immune memory represses IL-1β-mediated inflammation and support its potential clinical use in NLRP3-driven diseases.