Targeting the Toll-Like Receptor 4 Ameliorates Heart Failure in Aged Mice by Inhibiting the Formation of Neutrophil Extracellular Traps

Heart failure (HF) is a prevalent cardiovascular condition among the elderly population, with an incidence rate that continues to rise annually, highlighting the urgent need for effective therapeutic interventions. Sustained activation of Toll-like receptor 4 (TLR4) may contribute to left ventricular dysfunction and adverse cardiac remodeling through the induction of myocardial inflammation and oxidative stress - pathological processes that closely align with the hallmark features of HF. Preclinical studies in animal models have demonstrated that TLR4 deficiency improves cardiac function in aged mice; however, the precise role and underlying mechanisms of TLR4 in human HF remain poorly understood. This study aims to test the central hypothesis that TLR4 serves as a critical molecular link between chronic inflammation and the pathophysiology of HF. HF was induced in 18-month-old male C57BL/6J mice via continuous subcutaneous infusion of isoproterenol (ISO, 30 mg/kg/day) over a period of 3 weeks. Thereafter, mice received daily intraperitoneal injections of the TLR4 inhibitor TAK-242 (2 mg/kg), deoxyribonuclease I (DNase I, 5 mg/kg), or the peptidylarginine deiminase 4 (PAD4) inhibitor GSK484 (4 mg/kg) for 7 consecutive days. Cardiac function was assessed using a ultrasound imaging system. HE staining and Masson staining were employed to evaluate myocardial pathological changes and collagen deposition. ELISA was performed to measure serum levels of myeloperoxidase-DNA (MPO-DNA), neutrophil elastase-DNA (NE-DNA), cTnI, NT-proBNP, IL-1beta, IL-6 and TNF-alpha. Immunofluorescence staining was performed to detect the co-localization levels of Ly6G with myeloperoxidase (MPO) and citrullinated histone H3 (cit-H3) in myocardial tissue, in order to assess the formation level of neutrophil extracellular traps (NETs). Western blot were utilized to determine the expression level of TLR4 protein. The expression of TLR4 was significantly upregulated in the myocardial tissue of aged HF mice. Inhibition of TLR4 not only markedly improved cardiac function but also alleviated pathological damage to myocardial tissue and reduced collagen fiber deposition. Concurrently, it also decreased the serum levels of MPO-DNA, NE-DNA, NT-proBNP, cTnI, and inflammatory factors. Moreover, the colocalization levels of Ly6G with MPO or cit-H3 in myocardial tissue was also diminished. These findings were consistent with the effects observed following DNase I and GSK484 interventions. Targeting TLR4 can mitigate inflammatory responses and enhance cardiac function in HF mice by inhibiting NETs formation. Key words Heart failure " Cardiac function " Inflammation " Toll-like receptor 4 " Neutrophil extracellular traps.

Glycogen synthase kinase-3β (GSK-3β), a serine/threonine protein kinase, is widely distributed in mammalian brains. Since GSK-3β plays a vital role in the development of neurodegenerative disorders, the present study was designed to investigate the role of GSK-3β in the blood-brain barrier (BBB) permeability in aged mice. Morris water maze test was used to examine mouse cognitive function. BBB permeability was examined by the leakage of fluorescence signals of low-molecular weight dextran. GSK-3β inhibitor, 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8), was administrated in aged mice and in cultured mouse brain microvascular endothelial cells (bEnd.3). Compared with young mice, aged mice had increased leftover signals of dextran in the hippocampus and a lower score in the maze test, suggesting that aged mice have abnormal leakage of BBB and cognitive dysfunction. The protein expression of Toll-like receptor 4 (TLR4) was increased, whereas the protein expressions of junction proteins (claudin1 and claudin5) were reduced in endothelial cells of BBB in aged mice. Phosphorylated level of serine 9, an inhibitory residue in GSK-3β protein, was decreased. TDZD-8 treatment downregulated TLR4 protein expression, upregulated claudin1 and claudin5 protein expressions, and significantly improved cognitive function in aged mice. In bEnd.3 cells, TDZD-8 treatment reduced TLR4 expression and increased claudin5 expression in cells stimulated with lipopolysaccharides. In conclusion, the inhibition of GSK-3β activity downregulates aging-induced TLR4 expression and restores the BBB integrity, resulting in the improvement of cognitive function in aged mice.

Inhibition of TLR9 attenuates skeletal muscle fibrosis in aged sarcopenic mice via the p53/SIRT1 pathway.

BS-452682-4 EFFECTS OF CHRONIC ANGIOTENSIN CONVERTING ENZYME INHIBITION ON ATRIAL FUNCTION AND ARRHYTHMOGENESIS IN AGED AND FRAIL MICE

BackgroundObesity is a global health challenge linked to chronic non-communicable diseases. Low-grade inflammation and altered immune responses, including neutrophil extracellular trap (NET) formation, contribute to metabolic complications. Peptidyl arginine deiminase 4 (PAD4) is critical for NET formation, and its inhibition shows therapeutic potential. However, the sex-specific effects of PAD4 deficiency in diet-induced obesity remain unexplored.MethodsThis study investigated the impact of PAD4 deficiency on obesity-related metabolic pathologies in male and female C57BL/6 wild-type (WT) and Pad4(-/-) mice (n=5-6/group) fed a 22-week obesogenic cafeteria (CAF) diet. We hypothesized that PAD4 deficiency would ameliorate obesity-related metabolic and behavioral complications for both sexes. Body weight and composition, glucose and lipid metabolism, liver damage markers, and behavior were assessed. NETs were quantified via flow cytometry.ResultsPad4(-/-) males on CAF diet exhibited delayed obesity onset, lower body weight gain, and improved dyslipidemia than WT CAF males. This was associated with enhanced metabolic adaptation, indicated by higher brown adipose tissue temperature in Pad4(-/-) males. Conversely, Pad4(-/-) females on the CAF diet showed comparable weight gain to WT CAF females, similar or worsened dyslipidemia, impaired glucose metabolism, and higher liver lipid accumulation. While WT CAF females showed increased brown adipose tissue temperature, Pad4(-/-) CAF females did not.ConclusionPAD4 deficiency exerts sex-specific effects on obesity-related metabolic complications in mice. Inhibition of NET formation appears protective in males but not females on an obesogenic diet. These findings underscore the importance of considering sex as a biological variable in obesity research and developing sex-specific therapies.

It has been known for many years that LPS, neutrophils and platelets all participate in the pathogenesis of severe sepsis, but the inter-relationship between these players is completely unknown. Using flow chambers in vitro we suggest a novel innate immune response leading to enhanced trapping of bacteria in blood vessels. The mechanism involved platelet TLR4 detecting LPS in blood and inducing a unique response, specifically platelet binding to adherent neutrophils, but not platelet aggregation or P-selectin expression. Subsequently, the platelets stimulated very robust neutrophil activation leading to formation of NETs. These NETs retained their integrity under flow conditions and functioned to ensnare bacteria within the vasculature. Plasma from severely septic patients also induced TLR4-dependent platelet-neutrophil interactions leading to the production of NETs. We propose that this novel bacterial trapping mechanism would only occur under extreme conditions such as severe sepsis and platelet TLR4 (not leukocyte TLR4) functioned as the threshold switch for this innate immune response to occur. With the advent of antibiotics perhaps reducing the need for NET formation, we would propose that inhibiting platelet activation with TLR4 inhibitors may inhibit NET formation and reduce inadvertent tissue injury. This work was funded by: CIHR and AHFMR

To investigate the role of Toll-like receptor 4 (TLR4) pathway on myocardial injury and cardiac dysfunction in septic rats. According to the random number table, 18 male Sprague-Dawley (SD) rats were divided into control group, lipopolysaccharide (LPS) group and TLR4 specific inhibitor TAK242 pretreatment group (TAK242+LPS group) with 6 rats in each group. The rat model of septic cardiac dysfunction was induced by intraperitoneal injection of LPS 15 mg/kg, and the control group was given the same amount of normal saline. The TAK242+LPS group was intraperitoneally given injection of TAK242 [it was injected intraperitoneally at a dose of 3 mg/kg and dissolved in 10% dimethyl sulfoxide (DMSO) and 90% corn oil according to the concentration of 0.2 g/L] 3 hours before LPS stimulation. The control group and LPS group were given the same amount of 10% DMSO and 90% corn oil. The cardiac function of rats in each group was examined by Doppler echocardiography 14 hours after injection of LPS. The blood of abdominal aorta was taken and the level of serum troponin (cTn) was measured by enzyme linked immunosorbent assay (ELISA). Myocardial tissue was harvested for hematoxylin-eosin (HE) staining, and the morphological changes of myocardial tissue were observed under light microscope. The mRNA expressions of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in myocardial tissue were detected by real-time fluorescence quantitative polymerase chain reaction (qPCR). The protein expression of TLR4 in myocardial tissue was observed by immunohistochemical method. Western blotting was used to detect the levels of TLR4, nuclear factor-κB p65 (NF-κB p65) and its phosphorylation (p-NF-κB p65) in myocardial tissue. (1) The cardiac function and myocardial injury: Doppler echocardiography showed that the levels of left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume (LVESV) in the LPS group were significantly higher than those in the control group, while left ventricular ejection fraction (LVEF) and left ventricular shortened fraction (LVFS) were significantly lower than those in the control group. The degeneration, necrosis and inflammatory cell infiltration of cardiomyocytes were found with light microscope in the LPS group, and the levels of serum cTn were significantly higher than those in the control group, indicating that LPS-induced sepsis could cause cardiac dysfunction and myocardial injury. TAK242 blocking TLR4 pathway had a protective effect on cardiac function and myocardium during sepsis. LVEDV and LVESV in the TAK242+LPS group were significantly lower than those in the LPS group [LVEDV (μL): 71.25±21.16 vs. 118.01±11.89, LVESV (μL): 9.57±5.75 vs. 32.70±9.22, both P < 0.01]. LVEF and LVFS were significantly higher than those in the LPS group [LVEF: 0.868±0.075 vs. 0.722±0.095, LVFS: (59.88±8.46)% vs. (42.37±8.71)%, both P < 0.05]. Myocardial tissue injury was significantly reduced, and the serum cTn level was significantly lower than that in the LPS group (μg/L: 107.85±21.38 vs. 152.25±27.46, P < 0.05). (2) Inflammatory parameters: the results of qPCR, Western blotting and immunohistochemistry showed that the mRNA expressions of IL-6 and TNF-α, the expression of TLR4 protein and the p-NF-κB p65/NF-κB p65 ratio in the LPS group were significantly higher than those in the control group, indicating that LPS-induced sepsis could activate the inflammatory response mediated by TLR4/NF-κB pathway in the heart. However, blocking the TLR4 pathway by TAK242 could inhibit the TLR4/NF-κB pathway and reduce the myocardial inflammation in septic rats. The mRNA expressions of IL-6 and TNF-α, the expression of TLR4 protein and the p-NF-κB p65/NF-κB p65 ratio in the TAK242+LPS group were significantly lower than those in the LPS group [IL-6 mRNA (2-ΔΔCT): 10.44±3.30 vs. 107.50±29.48, TNF-α mRNA (2-ΔΔCT): 2.38±0.68 vs. 3.77±0.56, TLR4 protein (TLR4/GAPDH): 0.39±0.01 vs. 0.58±0.04, p-NF-κB p65/NF-κB p65 ratio: 1.21±0.11 vs. 2.10±0.18, all P < 0.05]. TAK242 can protect LPS-induced cardiac dysfunction and myocardial injury by blocking the TLR4 mediated inflammatory response.

Objective To investigate the expression and significance of Toll-like receptor 4 (TLR4) in renal tissue and peripheral blood of children with idiopathic nephrotic syndrome(INS). Methods The renal biopsy tissues of 78 children with INS diagnosed in the First Affiliated Hospital of Xinxiang Medical University from October 2015 to June 2018 and normal renal tissues of 21 children (control group 1) were collected, and the expressions of TLR4 in the renal tissue was detected by using immunohistochemical method.The expression of TLR4 in different renal pathological types and clinical types of INS was compared, and the correlation of TLR4 with 24-hour urinary protein and serum albumin was analyzed.The expression levels of TLR4 in peripheral blood of children with INS before and after treatment (active stage and remission stage) and 23 healthy children (control group 2) were detected by enzyme linked immunosorbent assay(ELISA). The serum expression levels of TLR4 in different renal pathological types and clinical types of INS were compared, and the correlation of TLR4 with 24-hour urinary protein and serum albumin was analyzed; The correlation between TLR4 expression in renal tubules and in the serum of children with INS was also analyzed. Results (1)Compared with the expression of TLR4 in normal renal tissues[(0.93±0.26)%], the expression of TLR4 in glomeruli and interstitium of all pathological types of INS [mesangial proliferative glomerulonephritis (MsPGN): (0.93 ± 0.21)%, focal segmental glomerulosclerosis (FSGS): (1.02±0.25)%, membranous glomerulonephritis(MN): (1.03±0.09)%, minimal change disease(MCD): (1.02±0.27)%]was not significantly different (F=0.741, P=0.562), but the expression of TLR4 in renal tubules[MCD: (82.94±4.62)%, MN: (63.54±1.98)%, MsPGN(42.32±2.97)%, FSGS: (22.60±2.07)%] was significantly increased (F=1 929.842, P<0.01), Especially, the expression of TLR4 in renal tubules of MCD type INS was significantly higher than that of MN, MsPG N and FSGS [MCD: (82.94±4.62)%, MN: (63.54±1.98)%, MsPGN: (42.32±2.97)%, FSGS: (22.60±2.07)%], and the differences were statistically significant(all P<0.01). TLR4 expression in renal tubules was the highest in steroid-sensitive nephrotic syndrome (SSNS) type and the lowest in INS patients with steroid-resistant nephrotic syndrome (SRNS) type, and the differences were statistically significant(F=220.951, P<0.01). (2)The expression of serum TLR4 in INS children at the active stage [MsPNG: (143.36±12.99) ng/L, FSGS(75.94±7.29) ng/L, MN(210.22±14.66) ng/L, MCD(283.93±21.58) ng/L]was significantly higher than that in INS children at remission stage [MsPNG: (29.51±4.93) ng/L, FSGS(15.66±3.78) ng/L, MN(45.40±5.73) ng/L, MCD(62.29±7.90) ng/L]and control group 2[(0.69 ± 0.33) ng/L], and the differences were statistically significant(all P<0.01); the expression of serum TLR4 in INS children at remission stage was significantly higher than that in the control group 2 (F=286.287, P<0.01). TLR4 had the highest expression level in serum of MCD type INS children at active and remission stages, followed by MN and FSGS successively.The expression of serum TLR4 was highest in SSNS and lowest in SRNS, and the differences were statistically significant (F=147.438, P<0.01). (3)The expression of TLR4 in renal tubules of children with INS[(62.82 ±20.94)%]was positively correlated with the expression of TLR4 in serum[(213.26±73.33) ng/L] (r=0.852, P< 0.05). The expression levels of TLR4 in renal tubules and serum of INS patients at active stage were positively correlated with 24-hour urinary protein level[(123.05±33.55) mg/kg] (r=0.401, 0.427, all P<0.05), and negatively correlated with serum albumin level[(19.54±3.55)g/L] (r=-0.602, -0.617, all P<0.05). Conclusions The expression of TLR4 in renal tubules and serum of children with INS increases, and may be related to different renal pathological types and clinical types of children with INS, as well as disease activity. Key words: Toll-like receptor 4; Kidney tissue; Serum; Idiopathic nephrotic syndrome; Child

The initiation of liver ischemia/reperfusion (I/R) injury results in the release of damage associated molecular patterns (DAMPs) such as HMGB1 and histones, which trigger innate immune and inflammatory cascade via Toll-like receptor 4 (TLR4) or TLR9. Infiltrated neutrophils contribute to the organ damage, innate immune and inflammatory responses after liver I/R. Formation of neutrophil extracellular trap (NET) has been recently found in response to various stimuli. However, the role of NETs during liver I/R remains unknown. We show that NETs form in the sinusoids of ischemic liver lobes in vivo, associated with increased serum level of myeloperoxidase (MPO)-DNA complexes and tissue level of citrullinated-histone H3 (NET markers) compared to control mice. Treatment with peptidyl-arginine-deiminase (PAD) 4 inhibitor or DNase I conferred significant protection after liver I/R evidenced by inhibition of NET formation, indicating the pathophysiological role of NETs in liver I/R injury. DAMPs, such as HMGB1 and histones stimulate NET formation through TLR4 and TLR9-MyD88 signaling pathways. After neutrophil depletion in mice, the adoptive transfer of TLR4 knockout (KO) or TLR9 KO neutrophils confers significant protection from liver I/R injury with significant decrease in NET formation. Conclusion: DAMPs released during liver I/R promotes NET formation through TLRs signaling pathway. NETs subsequently exacerbates organ damage and initiates inflammatory responses during liver I/R.

We evaluated the role of Toll-like receptor 4 (TLR4) in corneal epithelial wound healing. The expression of TLR4 during in vivo corneal epithelial wound healing was examined by immunostaining in mice. The expression and activation of TLR4 was studied in primary or telomerase-immortalized human corneal epithelial cells (HCEC). Scratch assay was performed to evaluate in vitro wound closure using live time-lapse microscopy. Transwell migration assay and Ki67 immunostaining were done to evaluate migration and proliferation, respectively. Lipopolysaccharide (LPS) was used to activate TLR4, whereas CLI-095 was used for its inhibition. The expression of inflammatory cytokines was determined by RT-PCR and ELISA. The activation of p42/44 and p38 was determined by immunoblotting. In the murine model, TLR4 immunostaining was noted prominently in the epithelium 8 hours after wounding. There was a 4-fold increase in the expression of TLR4 6 hours after in vitro scratch wounding (P < 0.001). Confocal microscopy confirmed the membrane localization of TLR4/MD2 complex. There was a significant increase in migration, proliferation, and wound closure in HCEC treated with LPS (P < 0.05), while there was significant decrease with TLR4 inhibition (P < 0.05). Addition of LPS to wounded HCEC resulted in a significant increase in the expression of IL-6, TNF-α, CXCL8/IL8, and CCL5/RANTES at the mRNA and protein levels. Likewise, LPS increased the activation of p42/44 and p38 in wounded HCEC. These results suggest that epithelial wounding induces the expression of functional TLR4. Toll-like receptor 4 signaling appears to contribute to early corneal epithelial wound repair by enhancing migration and proliferation.

Background:In vitro experiments have revealed that toll-like receptor 4 (TLR4) pathway is involved in the progression of immunoglobulin A nephropathy (IgAN) by induction of proinflammatory cytokines. Evidence showed that, in other disease models, peroxisome proliferator-activated receptor-γ (PPAR-γ) agonists have been shown to exert anti-inflammatory effects through suppression of the expression and activity of TLR4. However, the interaction between PPAR-γ and TLR4 in IgAN has not been fully studied both in vitro and in vivo. In this study, we explored whether TLR4 pathway attributed to the progression of IgAN in experimental rats.Methods:Bovine gamma globulin was used to establish IgAN model. Fifty-four Lewis rats were randomly divided into six groups: ControlTAK242, IgANTAK242, toll-like receptor 4 inhibitor (TAK242) groups (rats were administrated with TLR4 inhibitor, TAK242) and ControlPio, IgANPio, Pio groups (rats were administrated with PPAR-γ agonist, pioglitazone). Urinary albumin-to-creatinine ratio (ACR), serum creatinine, and blood urea nitrogen were detected by automatic biochemical analyzer. Renal histopathological changes were observed after hematoxylin-eosin staining, and the IgA deposition in glomeruli was measured by immunofluorescence staining. Real-time polymerase chain reaction and Western blotting were used to detect TLR4 and interleukin-1 beta (IL-1β) message ribonucleic acid (mRNA) and protein expression in renal tissues. Results were presented as mean ± standard deviation. Differences between groups were analyzed by one-way analysis of variance.Results:Compared to normal rats, experimental rats showed higher ACR (4.45 ± 1.33 mg/mmol vs. 2.89 ± 0.96 mg/mmol, P < 0.05), obvious IgA deposition with mesangial hypercellularity, hyperplasia of mesangial matrix accompanied by increased serum IL-1β (48.28 ± 13.49 pg/ml vs. 35.56 ± 7.41pg/ml, P < 0.05), and renal expression of IL-1β and TLR4. The biochemical parameters and renal pathological injury were relieved in both TAK242 group and Pio group. The expressions of renal tissue TLR4, IL-1β, and serum IL-1β were decreased in rats treated with TAK242, and the expression of TLR4 mRNA and protein was significantly reduced in Pio group compared to IgANPio group (1.22 ± 0.28 vs. 1.72 ± 0.45, P < 0.01, and 0.12 ± 0.03 vs. 0.21 ± 0.05, P < 0.01).Conclusions:Our study proves that inflammation mediated by TLR4 signaling pathway is involved in the progression of IgAN in rat models. Moreover, pioglitazone can inhibit the expression of TLR4 in IgAN.

CML-271: Neutrophil Extracellular Traps Are Increased in Chronic Myeloid Leukemia and Are Differentially Affected by Tyrosine Kinase Inhibitors

The abundance of inflammatory mediators in injured joint indicates innate immune reactions activated during temporomandibular joint osteoarthritis (TMJOA) progression. Toll‐like receptor 4 (TLR4) can mediate innate immune reaction. Herein, we aimed to investigate the expression profile and effect of TLR4 in the cartilage and subchondral bone of the discectomy‐induced TMJOA mice. The expression of TLR4 and NFκB p65 in the synovium of TMJOA patients was measured by immunohistochemistry, Western blotting and RT‐PCR. H&E and Masson staining were utilized to assess the damage of cartilage and subchondral bone of the discectomy‐induced TMJOA mice. A TLR4 inhibitor, TAK‐242, was used to assess the effect of TLR4 in the cartilage and subchondral bone of the discectomy‐induced TMJOA mice by Safranin O, micro‐CT, immunofluorescence and immunohistochemistry. Western blotting was used to quantify the expression and effect of TLR4 in IL‐1β–induced chondrocytes. The expression of TLR4 and NFκB p65 was elevated in the synovium of TMJOA patients, compared with the normal synovium. TLR4 elevated in the damaged cartilage and subchondral bone of discectomy‐induced TMJOA mice, and the rate of TLR4 expressing chondrocytes positively correlated with OA score. Intraperitoneal injections of TAK‐242 ameliorate the extent of TMJOA. Furthermore, TLR4 promotes the expression of MyD88/NFκB, pro‐inflammatory and catabolic mediators in cartilage of discectomy‐induced TMJOA. Besides, TLR4 participates in the production of MyD88/NFκB, pro‐inflammatory and catabolic mediators in IL‐1β–induced chondrocytes. TLR4 contributes to the damage of cartilage and subchondral bone in discectomy‐induced TMJOA mice through activation of MyD88/NFκB and release of pro‐inflammatory and catabolic mediators.

IL-18 induces profibrotic changes in TECs independent of TGF-β1 activity. IL-18 stimulates the TLR4 promoter via AP-1 activation to increase TLR4 expression in TECs and stimulates profibrotic changes in TECs through increased TLR4 expression/signaling. The profibrotic effect of IL-18 in TECs is mediated through stimulation of TLR4 expression via activation of AP-1. This represents a novel fibrotic signaling pathway in TECs independent of TGF-β1. IL-18 is an important mediator of obstruction-induced renal fibrosis and tubular epithelial cell injury independent of TGF-β1 activity. We sought to determine whether the profibrotic effect of IL-18 is mediated through Toll-like receptor 4 (TLR4). Male C57BL6 wild type and mice transgenic for human IL-18-binding protein were subjected to left unilateral ureteral obstruction versus sham operation. The kidneys were harvested 1 week postoperatively and analyzed for IL-18 production and TLR4 expression. In a separate arm, renal tubular epithelial cells (HK-2) were directly stimulated with IL-18 in the presence or absence of a TLR4 agonist, TLR4 antagonist, or TLR4 siRNA knockdown. Cell lysates were analyzed for TLR4, α-smooth muscle actin, and E-cadherin expression. TLR4 promotor activity, as well as AP-1 activation and the effect of AP-1 knockdown on TLR4 expression, was evaluated in HK-2 cells in response to IL-18 stimulation. The results demonstrate that IL-18 induces TLR4 expression during unilateral ureteral obstruction and induces TLR4 expression in HK-2 cells via AP-1 activation. Inhibition of TLR4 or knockdown of TLR4 gene expression in turn prevents IL-18-induced profibrotic changes in HK-2 cells. These results suggest that IL-18 induces profibrotic changes in tubular epithelial cells via increased TLR4 expression/signaling.

Da-yuan-yin decoction alleviates ulcerative colitis by inhibiting complement activation, LPS-TLR4/NF-κB signaling pathway and NET formation