Lipoxin A4 may attenuate the progression of obesity-related glomerulopathy by inhibiting NF-κB and ERK/p38 MAPK-dependent inflammation

A signaling network map of Lipoxin (LXA4): an anti-inflammatory molecule

Lipoxins (LXs) are a class of endogenous bioactive lipid mediators that are involved in the regulation of inflammation. They exert immunomodulatory effects by regulating the behaviour of various immune cells, including neutrophils, macrophages, and T and B cells, by promoting the clearance of apoptotic neutrophils. This helps to dampen inflammation and promote tissue repair. LXs regulate the expression of many inflammatory genes by modulating the levels of transcription factors, such as nuclear factor κB (NF-κB), activator protein-1 (AP-1), nerve growth factor-regulated factor 1A binding protein 1 (NGF), and peroxisome proliferator activated receptor γ (PPAR-γ), which are elevated in various diseases, such as respiratory tract diseases, renal diseases, cancer, neurodegenerative diseases, and viral infections. Lipoxin-mediated signaling is involved in chronic inflammation, cancer, diabetes-associated kidney disease, lung injury, liver injury, endometriosis, respiratory tract diseases, neurodegenerative diseases, chronic cerebral hypoperfusion, and retinal degeneration. In this study, we systematically investigated the intricate network of lipoxin signaling by analyzing the relevant literature. The resulting map comprised 467 molecules categorized as activation/inhibition, enzyme catalysis, gene and protein expression, molecular associations, and translocation events. This map serves as a valuable resource for understanding the complexity of lipoxin signaling and its impact on various cellular functions.

Emerging Roles and Therapeutic Applications of Arachidonic Acid Pathways in Cardiometabolic Diseases

Cardiometabolic disease has become a major health burden worldwide, with sharply increasing prevalence but highly limited therapeutic interventions. Emerging evidence has revealed that arachidonic acid derivatives and pathway factors link metabolic disorders to cardiovascular risks and intimately participate in the progression and severity of cardiometabolic diseases. In this review, we systemically summarized and updated the biological functions of arachidonic acid pathways in cardiometabolic diseases, mainly focusing on heart failure, hypertension, atherosclerosis, nonalcoholic fatty liver disease, obesity, and diabetes. We further discussed the cellular and molecular mechanisms of arachidonic acid pathway-mediated regulation of cardiometabolic diseases and highlighted the emerging clinical advances to improve these pathological conditions by targeting arachidonic acid metabolites and pathway factors.

Obesity-related glomerulopathy: recent advances in inflammatory mechanisms and related treatments

Obesity-related glomerulopathy, which is an obesity-triggered kidney damage, has become a significant threat to human health. Several studies have recently highlighted the critical role of inflammation in obesity-related glomerulopathy development. Additionally, excess adipose tissue and adipocytes in patients with obesity produce various inflammatory factors that cause systemic low-grade inflammation with consequent damage to vascular endothelial cells, exacerbating glomerular injury. Therefore, we conducted a comprehensive review of obesity-related glomerulopathy and addressed the critical role of obesity-induced chronic inflammation in obesity-related glomerulopathy pathogenesis and progression, which leads to tubular damage and proteinuria, ultimately impairing renal function. The relationship between obesity and obesity-related glomerulopathy is facilitated by a network of various inflammation-associated cells (including macrophages, lymphocytes, and mast cells) and a series of inflammatory mediators (such as tumor necrosis factor α, interleukin 6, leptin, adiponectin, resistin, chemokines, adhesion molecules, and plasminogen activator inhibitor 1) and their inflammatory pathways. Furthermore, we discuss a recently discovered relationship between micronutrients and obesity-related glomerulopathy inflammation and the important role of micronutrients in the body's anti-inflammatory response. Therefore, assessing these inflammatory molecules and pathways will provide a strong theoretical basis for developing therapeutic strategies based on anti-inflammatory effects to prevent or delay the onset of kidney injury.

Bicyclol alleviates obesity-induced renal injury by inhibiting JNK and NF-κB-mediated inflammation

Obesity is recognized as a major risk factor for chronic kidney disease (CKD), which is accompanied by increased renal lipid build-up, fibrosis, inflammation, apoptosis and pyroptosis. Bicyclol (BIC), a Chinese marketed hepatoprotective drug, has shown excellent anti-inflammatory, anti-fibrosis, anti-apoptotic, and lipid regulation effects in different animal models. In this study, we explored the role and mechanism of BIC in high-fat diet (HFD)-induced obesity-related nephropathy. Mice were fed with HFD for 24 weeks to develop obesity-related nephropathy, while mice in the BIC administration group were treated with BIC (50 mg/kg or 100 mg/kg, once every two days) at the last 12 weeks. We found that BIC treatment relieved the impairment of kidney structure and renal dysfunction caused by HFD. In addition, we found that BIC mitigated HFD-induced renal fibrosis, inflammation, apoptosis and pyroptosis by inhibiting JNK and NF-κB pathways. SV40-MES-13 cells treated with palmitate (PA) were used as the in vitro model. Our data show that BIC pre-administration relieved cellular damage caused by PA through suppressing JNK and NF-κB signaling pathways. In conclusion, we demonstrated that BIC attenuated obesity-induced renal injury by inhibiting chronic inflammation, fibrosis, apoptosis and pyroptosis via targeting JNK and NF-κB pathways. Our data suggested that BIC could be potentially used to prevent obesity-associated nephropathy, which warrants future investigation.

ACT001 Alleviates chronic kidney injury induced by a high-fat diet in mice through the GPR43/AMPK pathway

BACKGROUND

Roughly 10 -15% of global populace suffer from Chronic Kidney Disease(CKD). A major secondary disease that can progress to end-stage renal disease (ESRD) is obesity-associated kidney disease (ORG). Although clinical management strategies are currently available, morbidity and mortality rates are increasing. Thus, new solutions are needed. Intestinal permeability, systemic inflammation, and aberrant intestinal metabolites have all been linked to ORG.

PURPOSE

ACT001 has anti-inflammatory, redox-regulatory and antitumour activities. The current study was designed to examine how ACT001 affects ORG and analyze the fundamental processes.

METHODS

A high-fat diet (HFD) was used to generate ORG in female C57BL/6 J mice. ORG mice were divided into three groups at random: HFD, HFD + ACT001, HFD + polyphosphocholine (PPC). To assess renal and colonic damage, periodic acid-Schiff (PAS) and hematoxylin-eosin (HE) staining were used. Following that, renal inflammation, oxidative stress, lipid deposition, colonic inflammation, and intestinal permeability were evaluated by protein blotting, polymerase chain reaction (PCR), immunohistochemistry, and immunofluorescence staining. Lastly, the SCFAs content was assessed by gas chromatographymass spectrometry.

RESULTS

Mice in the HFD group displayed more severe albuminuria, glomerular hypertrophy, renal oxidative damage, inflammation, and lipid accumulation than mice with the normal diet (ND) group, as well as lower levels of intestinal SCFA valproic acid, colonic inflammation, and tight junction protein downregulation. ACT001 treatment restores the content of valproic acid in intestinal SCFAs, promotes the binding of SCFAs to renal GPR43, activates the AMPK signalling pathway. Therefore, it promotes the Nrf2-Keap1 signalling pathway and inhibits the NF-κB signalling pathway. SCFAs, additionally, augment colonic GPR43 concentrations, diminishing NLRP3 inflammasome expression and restoring ZO-1 and occludin protein levels.

CONCLUSION

This study is the first to look at ACT001's potential as a treatment for obesity-related kidney disease. Regulating GPR43 and AMPK signalling pathways, By controlling the GPR43 and AMPK signalling pathways, ACT001 improves colitis and the intestinal mucosal barrier, decreases renal lipid deposition, and suppresses inflammation and oxidative stress in the kidneys. According to this study, ACT001 could be a viable ORG therapy option.

Targeting Renal Proximal Tubule Cells in Obesity-Related Glomerulopathy

As a metabolic disorder, obesity can cause secondary kidney damage, which is called obesity-related glomerulopathy (ORG). As the incidence of obesity increases worldwide, so does the incidence of end-stage renal disease (ESRD) caused by ORGs. However, there is still a lack of effective strategies to prevent and delay the occurrence and development of ORG. Therefore, a deeper understanding and elaboration of the pathogenesis of ORG is conducive to the development of therapeutic drugs for ORG. Here, we review the characteristics of pathological lesions of ORG and describe the roles of lipid metabolism disorders and mitochondrial oxidative stress in the development of ORG. Finally, we summarize the current available drugs or compounds for the treatment of ORG and suggested that ameliorating renal lipid metabolism and mitochondrial function may be potential therapeutic targets for ORG.

Lipoxin receptor agonist and inhibition of LTA4 hydrolase prevent tight junction disruption caused by P. aeruginosa filtrate in airway epithelial cells

Airway diseases can disrupt tight junction proteins, compromising the epithelial barrier and making it more permeable to pathogens. In people with pulmonary disease who are prone to infection with Pseudomonas aeruginosa, pro-inflammatory leukotrienes are increased and anti-inflammatory lipoxins are decreased. Upregulation of lipoxins is effective in counteracting inflammation and infection. However, whether combining a lipoxin receptor agonist with a specific leukotriene A4 hydrolase (LTA4H) inhibitor could enhance these protective effects has not to our knowledge been investigated. Therefore, we explored the effect of lipoxin receptor agonist BML-111 and JNJ26993135 a specific LTA4H inhibitor that prevents the production of pro-inflammatory LTB4 on tight junction proteins disrupted by P. aeruginosa filtrate (PAF) in human airway epithelial cell lines H441 and 16HBE-14o. Pre-treatment with BML-111 prevented an increase in epithelial permeability induced by PAF and conserved ZO-1 and claudin-1 at the cell junctions. JNJ26993135 similarly prevented the increased permeability induced by PAF, restored ZO-1 and E-cadherin and reduced IL-8 but not IL-6. Cells pre-treated with BML-111 plus JNJ26993135 restored TEER and permeability, ZO-1 and claudin-1 to the cell junctions. Taken together, these data indicate that the combination of a lipoxin receptor agonist with a LTA4H inhibitor could provide a more potent therapy.

Metabolic phenotypes and risk of end-stage kidney disease in patients with type 2 diabetes

Background

Obesity often initiates or coexists with metabolic abnormalities. This study aimed to investigate the pathological characteristics and the independent or mutual relations of obesity and metabolic abnormalities with end-stage kidney disease (ESKD) in patients with type 2 diabetes (T2D) and associated diabetic kidney disease (DKD).

Methods

A total of 495 Chinese patients with T2D and biopsy-confirmed DKD between 2003 and 2020 were enrolled in this retrospective study. The metabolic phenotypes were based on the body weight index (BMI)-based categories (obesity, BMI ≥ 25.0 kg/m²) and metabolic status (metabolically unhealthy status, ≥ 1 criterion National Cholesterol Education Program Adult Treatment Panel III (NCEP/ATP III) excluding waist circumference and hyperglycemia) and were categorized into four types: metabolically healthy non-obesity (MHNO), metabolically healthy obesity (MHO), metabolically unhealthy non-obesity (MUNO), and metabolically unhealthy obesity (MUO). The pathological findings were defined by the Renal Pathology Society classification. Cox proportional hazards models were used to estimate hazard ratios (HRs) for ESKD.

Results

There are 56 (11.3%) MHNO patients, 28 (5.7%) MHO patients, 176 (35.6%) MUNO patients, and 235 (47.5%) MUO patients. The high prevalence of the Kimmelstiel-Wilson nodule and severe mesangial expansion were associated with obesity, whereas severe IFTA was related to metabolically unhealthy status. In the multivariate analysis, the adjusted HR (aHR) was 2.09 [95% confidence interval (CI) 0.99-4.88] in the MHO group, 2.16 (95% CI 1.20-3.88) in the MUNO group, and 2.31 (95% CI 1.27-4.20) in the MUO group compared with the MHNO group. Furthermore, the presence of obesity was insignificantly associated with ESKD compared with non-obese patients (aHR 1.22, 95% CI 0.88-1.68), while the metabolically unhealthy status was significantly associated with ESKD compared to the metabolically healthy status in the multivariate analysis (aHR 1.69, 95% CI 1.10-2.60).

Conclusion

Obesity itself was insignificantly associated with ESKD; however, adding a metabolically unhealthy status to obesity increased the risk for progression to ESKD in T2D and biopsy-proven DKD.

A Potential Link Between Visceral Obesity and Risk of Alzheimer's Disease

Alzheimer's disease (AD) is the most common type of dementia characterized by the deposition of amyloid beta (Aβ) plaques and tau-neurofibrillary tangles in the brain. Visceral obesity (VO) is usually associated with low-grade inflammation due to higher expression of pro-inflammatory cytokines by adipose tissue. The objective of the present review was to evaluate the potential link between VO and the development of AD. Tissue hypoxia in obesity promotes tissue injury, production of adipocytokines, and release of pro-inflammatory cytokines leading to an oxidative-inflammatory loop with induction of insulin resistance. Importantly, brain insulin signaling is involved in the pathogenesis of AD and lower cognitive function. Obesity and enlargement of visceral adipose tissue are associated with the deposition of Aβ. All of this is consonant with VO increasing the risk of AD through the dysregulation of adipocytokines which affect the development of AD. The activated nuclear factor kappa B (NF-κB) pathway in VO might be a potential link in the development of AD. Likewise, the higher concentration of advanced glycation end-products in VO could be implicated in the pathogenesis of AD. Taken together, different inflammatory signaling pathways are activated in VO that all have a negative impact on the cognitive function and progression of AD except hypoxia-inducible factor 1 which has beneficial and neuroprotective effects in mitigating the progression of AD. In addition, VO-mediated hypoadiponectinemia and leptin resistance may promote the progression of Aβ formation and tau phosphorylation with the development of AD. In conclusion, VO-induced AD is mainly mediated through the induction of oxidative stress, inflammatory changes, leptin resistance, and hypoadiponectinemia that collectively trigger Aβ formation and neuroinflammation. Thus, early recognition of VO by visceral adiposity index with appropriate management could be a preventive measure against the development of AD in patients with VO.

Lipoxin A4 promotes adipogenic differentiation and browning of mouse embryonic fibroblasts

Recently, it has been irrefutably discovered that brown adipocytes dissipate energy as heat and protect against obesity. Researchers make great efforts to explore approaches for its activation. Lipoxin A4 (LXA4) has been proven to reverse adipose tissue inflammation and improve insulin resistance, but its function on brown adipocyte differentiation has been poorly understood, which therefore to be investigated in the present study. Mouse embryonic fibroblasts (MEFs) were induced and differentiated to model brown adipocytes, and treated with LXA4 at 0, 1, 5, and 10 nM for 0-14 d. Afterwards, Oil Red O staining detected lipid droplets. In differentiated MEFs with or without LXA4 (10 nM) treatment, western blot and quantitative real-time polymerase chain reaction (qRT-PCR) assessed adipocyte browning marker uncoupling protein 1 (UCP-1), and brown adipogenesis markers peroxisome proliferator-activated receptor gamma (PPARγ), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α), cyclooxygenase-2 (COX-2), and positive regulation domain containing 16 (PRDM16) as well as lipogenic genes of stearoyl-CoA desaturase 1 (SCD1), fatty acid synthase (FASN), glucose transporter type 4 (GLUT4), and carbohydrate response element binding protein (ChREBP). The induced differentiation of MEFs toward brown adipocytes was successful. LXA4 promoted intracellular accumulation of lipid droplets of induced cells and increased UCP-1 expression in a dose- or time-dependent manner. Under the administration of LXA4, brown adipogenesis markers and lipogenic genes were further upregulated. LXA4 made a contribution to induce differentiation of MEFs to brown adipocytes, which could be regarded a new drug target for obesity management.

Therapeutic potential of pro-resolving mediators in diabetic kidney disease

Renal microvascular disease associated with diabetes [Diabetic kidney disease - DKD] is the leading cause of chronic kidney disease. In DKD, glomerular basement membrane thickening, mesangial expansion, endothelial dysfunction, podocyte cell loss and renal tubule injury contribute to progressive glomerulosclerosis and tubulointerstitial fibrosis. Chronic inflammation is recognized as a major pathogenic mechanism for DKD, with resident and circulating immune cells interacting with local kidney cell populations to provoke an inflammatory response. The onset of inflammation is driven by the release of well described proinflammatory mediators, and this is typically followed by a resolution phase. Inflammation resolution is achieved through the bioactions of endogenous specialized pro-resolving lipid mediators (SPMs). As our understanding of SPMs advances 'resolution pharmacology' based approaches using these molecules are being explored in DKD.

Lipoxin A4 promotes autophagy and inhibits overactivation of macrophage inflammasome activity induced by Pg LPS

Objective

To explore the role of lipoxin A4 (LXA4) on inflammasome and inflammatory activity in macrophages activated by Porphyromonas gingivalis lipopolysaccharide (PgLPS) one of the major causative agents of chronic periodontitis.

Methods

The mouse macrophage cell line RAW264.7 was used to produce an activated inflammation model. Markers of inflammasome and inflammatory activity and autophagy were assessed by ELISA, reverse transcription polymerase chain reaction (RT-PCR), and Western blot assay.

Results

Markers of inflammasome activity, inflammation and autophagy increased with Pg LPS concentration. They also increased with increasing exposure to Pg LPS up to 12h but decreased at 24h. However, markers of autophagy increased. Phosphorylated NF-κBp65 decreased with LXA4, which was similar to results obtained with the autophagy inducer, rapamycin.

Conclusions

LXA4 promoted autophagy and inhibited activation of inflammasomes and inflammation markers in macrophage inflammation induced by PgLPS and this action was linked to the phosphorylation of NF-κB.

Promoting resolution in kidney disease: are we nearly there yet?

PURPOSE OF REVIEW

Nephrology lacks effective therapeutics for many of the presentations and diseases seen in clinical practice. In recent decades, we have come to understand the central place of inflammation in initiating and propagating kidney disease, and, research in more recent years has established that the resolution of inflammation is a highly regulated and active process. With this, has evolved an appreciation that this aspect of the host inflammatory response is defective in kidney disease and led to consideration of a therapeutic paradigm aiming to harness the activity of the molecular drivers of the resolution phase of inflammation. Fatty-acid-derived Specialized pro-resolving mediators (SPMs), partly responsible for resolution of inflammation have gained traction as potential therapeutics.

RECENT FINDINGS

We describe our current understanding of SPMs for this purpose in acute and chronic kidney disease. These studies cement the place of inflammation and its defective resolution in the pathogenesis of kidney disease, and highlight new avenues for therapy.

SUMMARY

Targeting resolution of inflammation is a viable approach to treating kidney disease. We optimistically look forward to translating these experimental advances into tractable therapeutics to treat kidney disease.

Obesity-Related Glomerulopathy: From Mechanism to Therapeutic Target

Obesity-related glomerulopathy (ORG) is a secondary glomerular disease caused by obesity, with clinical manifestations such as proteinuria and glomerulomegaly. Currently, the high incidence of obesity brings a change in the spectrum of kidney diseases across the globe, including China. ORG has become another important secondary nephropathy leading to end-stage renal disease (ESRD), and its incidence has increased significantly. This trend is bound to bring about a serious socioeconomic burden. Therefore, it is urgent to study its pathogenesis and intervention measures. Currently, the occurrence and development mechanisms in ORG are complicated by many factors, which are still unclear. In the past 20 years, with the continuous intensive research on mechanisms such as hypoxia in the metabolic process, immune inflammation, and pyroptosis, there have been new advances in the mechanism of ORG, especially the important role of inflammation in podocyte injury and its impact on the progress of ORG. Here, we briefly review the possible pathogenic role of the inflammasome in the podocyte damage in ORG and summarize the possible therapeutical strategies targeting inflammasome.

Pro-resolving lipid mediators: regulators of inflammation, metabolism and kidney function

Obesity, diabetes mellitus, hypertension and cardiovascular disease are risk factors for chronic kidney disease (CKD) and kidney failure. Chronic, low-grade inflammation is recognized as a major pathogenic mechanism that underlies the association between CKD and obesity, impaired glucose tolerance, insulin resistance and diabetes, through interaction between resident and/or circulating immune cells with parenchymal cells. Thus, considerable interest exists in approaches that target inflammation as a strategy to manage CKD. The initial phase of the inflammatory response to injury or metabolic dysfunction reflects the release of pro-inflammatory mediators including peptides, lipids and cytokines, and the recruitment of leukocytes. In self-limiting inflammation, the evolving inflammatory response is coupled to distinct processes that promote the resolution of inflammation and restore homeostasis. The discovery of endogenously generated lipid mediators - specialized pro-resolving lipid mediators and branched fatty acid esters of hydroxy fatty acids - which promote the resolution of inflammation and attenuate the microvascular and macrovascular complications of obesity and diabetes mellitus highlights novel opportunities for potential therapeutic intervention through the targeting of pro-resolution, rather than anti-inflammatory pathways.

Lipoxin A4-Mediated p38 MAPK Signaling Pathway Protects Mice Against Collagen-Induced Arthritis

The aim of the article was to study the mechanism of Lipoxin A4 (LXA4)-mediated p38 MAPK pathway protecting mice against collagen-induced arthritis (CIA). The impact of LXA4 (0, 5, 10, 15 nM) on synoviocytes proliferation of CIA mice was detected using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. CIA mice were treated with LXA4, SB203580 (a p38 inhibitor), and/or anisomycin (a p38 agonist), and the arthritis severity score in each mouse was determined. The gene or protein expressions were detected with Western Blotting, ELISA, or qRT-PCR. LXA4 inhibited the synoviocytes proliferation of CIA mice with decreased levels of TNF-α, IL-6, IL-1β, and IFN-γ and reduced p-p38/total p38 expression in synoviocytes in a dose-dependent manner. LXA4 levels were decreased in synovial tissues and plasma of CIA mice, but p-p38/total p38 expression was increased in synovial tissues. LXA4 could downregulate p-p38/total p38 expression in synovial tissues of CIA mice. Both LXA4 and SB203580 reduced arthritis severity score of CIA mice with the reduction of synovial tissue hyperplasia and inflammatory cell infiltration. CIA mice treated with LXA4 and SB203580 had lower levels of TNF-α, IL-6, IL-1β, and IFN-γ, accompanying decreased MDA as well as increased SOD, CAT,and GPx. However, anisomycin could reverse the protect effects of LXA4 on CIA mice regarding the abovementioned inflammatory factors and oxidative stress indexes. LXA4 protected mice against collagen-induced arthritis via inhibiting p38 MAPK signaling pathway, which may be a potential new therapeutic target for rheumatoid arthritis.

Obesity-Related Glomerulopathy: A Latent Change in Obesity Requiring More Attention

BACKGROUND

Obesity has become a major public health problem, and the prevalence of kidney diseases has increased in parallel. Among kidney diseases caused by metabolic disorders, obesity-related glomerulopathy (ORG) is secondary to obesity.

SUMMARY

ORG is mainly caused by glomerular hyperfiltration, dysregulation of hormone and cytokine secretion in adipose tissues, and ectopic lipid accumulation in renal cells. ORG is pathologically characterized by glomerular hypertrophy, with or without focal and segmental glomerulosclerosis. Patients with ORG usually present with proteinuria concomitant with metabolic disorders such as dyslipidemia and hypertension. Weight loss, RAAS inhibitors, and improved insulin resistance can reduce the progression of ORG.

CONCLUSION

ORG is a growing renal pathological change in obese individuals, and a comprehensive understanding of the disease is pivotal to avoid its occurrence and improve quality of life for those with obesity. Key Messages:This review comprehensively describes the characteristics of ORG in pathological changes, clinical manifestations, pathogeneses and treatments.

The inhibition of Nrf2 accelerates renal lipid deposition through suppressing the ACSL1 expression in obesity-related nephropathy

Background: Obesity has become a worldwide epidemic, and the incidence of obesity is increasing year by year. Obesity-related nephropathy (ORN) is a common kidney complication of obesity. Long-chain acyl-CoA synthetases-1, (ACSL1), is a key enzyme in the oxidative metabolism of fatty acids in mitochondria and ACSL1 may play a direct role in renal lipid deposition and promote the progress of ORN. In this study, we focus on the renoprotective role of ACSL1 in ORN.

Methods: Electron microscopy, immunohistochemical (IHC) staining, Western blot, and real-time PCR were used to detect the expression of ACSL1and Nrf2 in ORN patients, ob/ob mice and palmitic acid (PA)-treated HK-2 cells. Oil red staining and Elisa Kit were used to detect the intracellular FFA and TG contents in ob/ob mice and PA-treated HK-2 cells. Dihydroethidium (DHE) staining and the MDA/SOD measurement were used to detect the ROS production. In order to demonstrate the role of ACSL1 and the interaction between ACSL1 and Nrf2 in ORN, related siRNA and plasmid were transfected into HK-2 cells.

Results: More ROS production and renal lipid deposition have been found in ORN patients, ob/ob mice and PA-treated HK-2 cells. Compared with control, all the expression of ACSL1and Nrf2 were down-regulated in ORN patients, ob/ob mice and PA-treated HK-2 cells. The Nrf2 could regulate the expression of ACSL1 and the ACSL1 played the direct role in renal lipid deposition.

Conclusions: The Nrf2 is inhibited in ORN, resulting more ROS production and oxidative stress. Increased oxidative stress will suppress the expression of ACSL1, which could increase the intracellular FFA and TG contents, ultimately leading to renal lipid deposition in renal tubulars and accelerating the development of ORN.

Role of the lipoxin A4 receptor in the development of neutrophil extracellular traps in Leishmania infantum infection

BACKGROUND

Neutrophils play an immunomodulatory role through the release of neutrophil extracellular traps (NETs). NETs are released in response to Leishmania infection, but the mechanism of NET extrusion has not been elucidated. The lipoxin A4 receptor on neutrophils is crucial for the inflammatory response and immune regulation of many diseases, including Leishmania infection. Therefore, in the present study, we tried to explore whether Leishmania infantum promastigotes stimulate neutrophil activation and NET release via activating the lipoxin A4 receptor.

RESULTS

Leishmania infantum promastigotes stimulated neutrophil activity, but blocking of the lipoxin A4 receptor with its antagonist Boc prior to L. infantum stimulation abrogated these effects. Neutrophils showed citrullinated histone H3 expression and simultaneous NET extrusion on L. infantum stimulation, but a decline in both was observed on blocking of the lipoxin A4 receptor. Moreover, differentiated HL-60 cells with lipoxin A4 receptor silencing showed a decrease in citrullinated histone H3 expression as compared to the unsilenced HL-60 samples on stimulation with promastigotes.

CONCLUSIONS

Leishmania infantum promastigotes altered the characteristics of neutrophils and induced NET extrusion by activating the lipoxin A4 receptor. The lipoxin A4 receptor may have potential as a therapeutic target in relation to NET extrusion in the treatment of leishmaniasis, but its mechanisms of action need to be explored in more depth.

Protective effects of liraglutide on glomerular podocytes in obese mice by inhibiting the inflammatory factor TNF-α-mediated NF-κB and MAPK pathway

OBJECTIVE

To evaluate the protective effects of Glucagon-like peptide-1(GLP-1) receptor agonist (liraglutide) on glomerular podocytes of obese mice, and explore the possible underlying mechanism.

METHODS

Twelve of the thirty-four healthy and clean male mice were randomly selected as the normal control group. The remaining twenty-two mice were included in the high-fat diet (HFD) feeding group. After twelve weeks of high-fat diet and normal diet, two mice each from the HFD feeding group and the normal control group were randomly selected and sacrificed to suggested that the modeling was successful in the HFD feeding group. Then, twenty mice were randomly divided into HFD + liraglutide group (liraglutide group, n = 10) and HFD group (n = 10). The morphology and the structure of glomerular podocytes were observed using electron microscopy. Podocyte foot process diameter, glomerular basement membrane thickness were measured. ELISA was performed to determine the serum tumor necrosis factor α (TNF-α) level. The expression levels of TNF-α protein and nuclear factor-kappa B (NF-κB) in kidney tissues, extracellularsignal regulating kinase(ERK), c-Jun N-terminal kinase (JNK) and p38MAPK in the mitogenactivated protein kinases(MAPK) pathway were detected by western blotting.

RESULTS

HFD-feeding caused significant renal injury, podocyte pathological changes, podocyte foot process diameter and glomerular basement membrane thickness were significantly increased compared with the control group. Liraglutide injection significantly alleviated HFD-induced effects on renal functions and podocyte morphology, as 24 h urine protein, urinary albumin and podocyte histomorphology. Moreover, HFD-induced Inflammatory reaction were obviously attenuated by Liraglutide administration, so did the HFD-induced activation of TNF-α-mediated NF-κB and MAPK pathways.

CONCLUSION

Liraglutide reduced urinary albumin excretion in obesity-related glomerulopathy model mice, and improved podocyte morphology and structural damage. The mechanism may be partly related to the inhibition of TNF-α-mediated NF-κB and MAPK pathways.

Lipoxin A4 Methyl Ester Reduces Early Brain Injury by Inhibition of the Nuclear Factor Kappa B (NF-κB)-Dependent Matrix Metallopeptidase 9 (MMP-9) Pathway in a Rat Model of Intracerebral Hemorrhage

Background

Intracerebral hemorrhage (ICH) is associated with inflammation and disruption of the blood-brain barrier (BBB). Lipoxin A4 methyl ester (LXA4 ME), is a stable synthetic analog of lipoxin with anti-inflammatory properties. This study aimed to investigate the effects of LXA4 ME in a rat model of ICH.

Material/Methods

Male Sprague-Dawley rats (n=120), between 12–13 weeks of age, were divided into the sham group (sham-operated), the vehicle-treated group (ICH+vehicle), the LXA4 ME-L group (ICH+low-dose LXA4 ME, 10 ng/d), and the LXA4 ME-H group (ICH+high-dose LXA4 ME, 100 ng/d). The ICH model was created by injection of autologous blood into the right basal ganglia. LXA4 ME was injected into the ventricle 10 min after the development of ICH. A modified neurological severity score (mNSS), rotarod latencies, and brain water content were used to evaluate the rats. The TUNEL assay measured neuronal cell death. Western blot was used to measure protein expression of nuclear factor kappa B (NF-κB), matrix metalloproteinase-9 (MMP-9), zonula occludens-1 (ZO-1), and claudin-5.

Results

In the rat model of ICH, treatment with LXA4 ME reduced the levels of proinflammatory cytokines, improved neurologic function, reduced neuronal apoptosis, and reduced cerebral edema associated with damage to the BBB, and reduced the expression levels of NF-κB, MMP-9, ZO-1, and claudin-5.

Conclusions

In a rat model of ICH, treatment with LXA4 reduced early brain injury and protected the BBB by inhibiting the NF-κB-dependent MMP-9 pathway.

Is lipoxin A4 an effective treatment on fat embolism syndrome by attenuating pro-inflammatory response?

Fat embolism syndrome (FES) is characterized by high mortality and lack of effective treatment, the symptomatic therapy is most used to relieve clinical symptoms. Some studies have shown that inflammation is one of the main pathogeneses of FES. Lipoxin A4 is an endogenous-derived anti-inflammatory substance which was discovered recently. It can alleviate inflammatory response and promote inflammation resolution, and is referred as brake signal of inflammation. Therefore we hypothesize that lipoxin A4 may have a remission and therapeutic effect on FES by attenuating FES-induced inflammatory responses.