PPAR-α Agonist WY-14643 Inhibits LPS-Induced Inflammation in Synovial Fibroblasts via NF-kB Pathway

The Effect of Omega-3 on Mitigating Exercise-Induced Muscle Damage

Exercise-induced muscle damage (EIMD) refers to muscle injuries following exercises involving repetitive eccentric muscle contractions. The resultant inflammation and muscle protein leakage into the circulation lead to muscle pain and strength deficit, compromising athletic performance. This narrative review summarizes the current evidence on the effect and mechanism of omega-3 polyunsaturated fatty acids (n-3 PUFA) in potentially mitigating EIMD. Several studies suggested n-3 PUFA's role in alleviating delayed-onset muscle soreness, particularly in untrained individuals and those receiving higher doses of continuous supplementation. However, its impact on muscle strength attenuation and the reduction of performance post-exercise remains inconclusive. Also unclear are n-3 PUFA's effects on the reduction of circulating pro-inflammatory substances and muscle proteins. One of the possible mechanisms is its anti-inflammatory property, which involves its ability to incorporate into cell membranes and displace prostaglandin precursor. n-3 PUFA also decreases cyclooxygenase production and can be converted into specialized pro-resolving mediators (SPMs), further reducing inflammation. Moreover, n-3 PUFA's incorporation into cell membranes alters cell membrane properties, diminishing protein release during muscle breakdown. n-3 PUFA exhibits analgesic effects through SPM-induced modulation of receptors and ion channels, reducing both peripheral and central sensitization. n-3 PUFA also diminishes mitochondrial free radical production and accelerates nerve conduction, thereby improving voluntary muscle activation.

Decrypting the Possible Mechanistic Role of Fenofibrate in Alzheimer's Disease and Type 2 Diabetes: The Truth and Mystery

Alzheimer's disease (AD) is a neurodegenerative disease caused by the progressive deposition of extracellular amyloid beta (Aβ) and intracellular neurofibrillary tangles (NFTs). Of note, metabolic disorders such as insulin resistance (IR) and type 2 diabetes (T2D) are associated with the development of brain IR and associated neurodegeneration. In addition, AD neuropathology and linked cognitive impairment accelerate the development of peripheral IR and the progression of T2D. Therefore, there is a bidirectional relationship between T2D and AD. It has been demonstrated that AD and T2D induce dysregulation of peroxisome proliferator-activated receptor alpha (PPAR-α) leading to the central and peripheral metabolic disturbances. Hence, dysregulated PPAR-α could be a shared mechanism in both AD and T2D, and restoration of PPAR-α signalling by PPAR-α agonist fenofibrate (FN) may alleviate T2D and AD. Therefore, this review aims to shed light on the potential involvement of PPAR-α in T2D and AD, and how FN could be effective in the management of AD. FN seems to be effective in both AD and T2D by dual neuroprotective and antidiabetic effects that can mitigate AD neuropathology and T2D-related complications by modulating various cellular processes and inflammatory signalling pathways. In conclusion, FN could be a possible candidate in the management of AD and T2D by modulating different signalling pathways involved in the pathogenesis of these conditions.

Neuroprotective effects of L-carnitine towards oxidative stress and inflammatory processes: a review of its importance as a therapeutic drug in some disorders

L-carnitine (LC) is a natural compound crucial for transporting long-chain fatty acids into mitochondria for ATP production. It is found mainly in red meat, fish, and dairy products, in addition to being synthesized by the body. LC is supplemented in patients with organic acidemias since it corrects secondary carnitine deficiency and accelerates the removal of the accumulated acyl organic acid derivative groups. Recently, it was also shown to behave as an antioxidant and an anti-inflammatory agent in various pathological conditions like hypertension, diabetes, and neurodegenerative diseases. Inflammation is a complex response to tissue damage or infection associated with oxidative stress. LC has been implicated in reducing inflammatory cytokines and other biomarkers. Recent studies suggest that LC supplementation reduces inflammation in chronic kidney disease, cardiovascular disease, and neuroinflammation. LC supplementation has been effective in reducing inflammatory markers like C-reactive protein (CRP) and interleukins (IL-6, TNF-α) in various pathologies, including septic shock and polycystic ovary syndrome (PCOS). It has also been shown to reduce cardiovascular events in patients with end-stage renal disease. In experimental models, LC revealed neuroprotective effects, improving memory and reducing neuronal death. Additionally, in spinal cord ischemia-reperfusion injury and acute myocardial infarction, LC treatment diminished inflammation and oxidative stress while improving neurological and cardiac functions. In conclusion, LC supplementation demonstrates significant potential properties in reducing inflammation and improving health outcomes in various pathological conditions, making it a subject of increasing interest in medical research. This article aims to review the literature on the anti-inflammatory and antioxidant effects of LC in different pathologies.

Pharmacology, medical uses, and clinical translational challenges of Saikosaponin A: A review

Saikosaponin A (SSA), the primary active monomer derived from the Radix bupleuri, demonstrates a diverse array of pharmacological activities, including anti-inflammatory, antitumor, analgesic, anti-fibrotic, antidepressant, and immune-modulating properties. Despite its potential therapeutic impact on various human diseases, comprehensive studies exploring SSA's efficacy in these contexts remain limited. This review synthesizes the current research landscape regarding SSA's therapeutic applications across different diseases, highlighting critical insights to overcome existing limitations and clinical challenges. The findings underscore the importance of further investigations into SSA's mechanisms of action, facilitating the development of targeted therapeutic strategies and their translation into clinical practice.

Autophagy and PPARs/NF-κB-associated inflammation are involved in hepatotoxicity induced by the synthetic phenolic antioxidant 2,4-di-tert-butylphenol in common carp (Cyprinus carpio)

The synthetic phenolic antioxidant 2,4-di-tert-butylphenol (2,4-DTBP) is an emergent contaminant and can disrupt the delicate balance of aquatic ecosystems. This study aimed to investigate 2,4-DTBP-induced hepatotoxicity in common carp and the underlying mechanisms involved. Sixty common carp were divided into four groups and exposed to 0 mg/L, 0.01 mg/L, 0.1 mg/L or 1 mg/L 2,4-DTBP for 30 days. Here, we first demonstrated that 2,4-DTBP exposure caused liver damage, manifested as hepatocyte nuclear pyknosis, inflammatory cell infiltration and apoptosis. Moreover, 2,4-DTBP exposure induced hepatic reactive oxygen species (ROS) overload and disrupted antioxidant capacity, as indicated by the reduced activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). In addition, transmission electron microscopy revealed that 2,4-DTBP exposure induced autophagosome accumulation in the liver of common carp. Western blot analysis further revealed that 2,4-DTBP exposure significantly decreased the protein levels of mTOR and increased the LC3II/LC3I ratio. Furthermore, 2,4-DTBP exposure inhibited lysozyme (LZM) and alkaline phosphatase (AKP) activity; decreased immunoglobulin M (IgM), complement 3 (C3), and complement 4 (C4) levels in the serum; increased the mRNA levels of proinflammatory cytokines (NF-κB, TNF-α, IL-1β and IL-6); and increased the mRNA levels of three types of proliferator-activated receptors (PPARs) (α, β/δ and γ). Molecular docking revealed that 2,4-DTBP directly binds to the internal active pocket of PPARs. Overall, we concluded that 2,4-DTBP exposure in aquatic systems could induce hepatotoxicity in common carp by regulating autophagy and controlling inflammatory responses. The present study provides new insights into the hepatotoxicity mechanism induced by 2,4-DTBP in aquatic organisms and furthers our understanding of the effects of 2,4-DTBP on public health and ecotoxicology.

Circulating endocannabinoidome signatures of disease activity in amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE

Preclinical studies of amyotrophic lateral sclerosis (ALS) have shown altered endocannabinoid (eCB) signalling that may contribute to the disease. Results from human studies are sparse and inconclusive. The aim of this study was to determine the association between serum levels of eCBs or their congeners, the so-called endocannabinoidome, and disease status and activity in ALS patients.

METHODS

Serum concentrations of 2-arachidonoylglycerol and N-arachidonoylethanolamine (AEA), and AEA congeners palmitoylethanolamide (PEA), oleoylethanolamide (OEA), eicosapentaenoylethanolamide (EPEA), 2-docosahexaenoylglycerol (2-DHG) and docosahexaenoylethanolamide (DHEA) were measured in samples from 65 ALS patients, 32 healthy controls (HCs) and 16 neurological disease controls (NALS). A subset of 46 ALS patients underwent a longitudinal study. Disease activity and progression were correlated with eCB and congener levels.

RESULTS

Most circulating mediators were higher in ALS than HCs (all p < 0.001), but not NALS. Across clinical stages, ALS patients showed increased levels of PEA, OEA and EPEA (all p < 0.02), which were confirmed by the longitudinal study (all p < 0.03). Serum PEA and OEA levels were independent predictors of survival and OEA levels were higher in patients complaining of appetite loss. Cluster analysis revealed two distinct profiles of circulating mediators associated with corresponding patterns of disease activity (severe vs. mild). Patients belonging to the 'severe' cluster showed significantly higher levels of OEA and PEA and lower levels of 2-DHG compared to NALS and HCs.

CONCLUSION

Circulating endocannabinoidome profiles are indicative of disease activity, thus possibly paving the way to a personalized, rather than a 'one-fits-all', therapeutic approach targeting the endocannabinoidome.

Anti-steatotic effects of PPAR-alpha and gamma involve gut-liver axis modulation in high-fat diet-fed mice

AIM

To evaluate the effects of PPARα and PPARγ activation (alone or in combination) on the gut-liver axis, emphasizing the integrity of the intestinal barrier and hepatic steatosis in mice fed a high saturated fat diet.

METHODS

Male C57BL/6J were fed a control diet (C) or a high-fat diet (HF) for ten weeks. Then, a four-week treatment started: HF-α (WY14643), HF-γ (low-dose pioglitazone), and HF-αγ (combination).

RESULTS

The HF caused overweight, insulin resistance, impaired gut-liver axis, and marked hepatic steatosis. Treatments reduced body mass, improved glucose homeostasis, and restored the gut microbiota diversity and intestinal barrier gene expression. Treatments also lowered the plasma lipopolysaccharide concentrations and favored beta-oxidation genes, reducing macrophage infiltration and steatosis in the liver.

CONCLUSION

Treatment with PPAR agonists modulated the gut microbiota and rescued the integrity of the intestinal barrier, alleviating hepatic steatosis. These results show that these agonists can contribute to metabolic-associated fatty liver disease treatment.

Klotho exerts protection in chronic kidney disease associated with regulating inflammatory response and lipid metabolism

BACKGROUND

The anti-aging protein Klotho plays a protective role in kidney disease, but its potential as a biomarker for chronic kidney disease (CKD) is controversial. Additionally, the main pathways through which Klotho exerts its effects on CKD remain unclear. Therefore, we used bioinformatics and clinical data analysis to determine its role in CKD.

RESULTS

We analyzed the transcriptomic and clinical data from the Nephroseq v5 database and found that the Klotho gene was mainly expressed in the tubulointerstitium, and its expression was significantly positively correlated with estimated glomerular filtration rate (eGFR) and negatively correlated with blood urea nitrogen (BUN) in CKD. We further found that Klotho gene expression was mainly negatively associated with inflammatory response and positively associated with lipid metabolism in CKD tubulointerstitium by analyzing two large sample-size CKD tubulointerstitial transcriptome datasets. By analyzing 10-year clinical data from the National Health and Nutrition Examination Survey (NHANES) 2007-2016, we also found that Klotho negatively correlated with inflammatory biomarkers and triglyceride and positively correlated with eGFR in the CKD population. Mediation analysis showed that Klotho could improve renal function in the general population by modulating the inflammatory response and lipid metabolism, while in the CKD population, it primarily manifested by mediating the inflammatory response. Restricted cubic spline (RCS) analysis showed that the optimal concentration range for Klotho to exert its biological function was around 1000 pg/ml. Kaplan-Meier curves showed that lower cumulative hazards of all-cause mortality in participants with higher levels of Klotho. We also demonstrated that Klotho could reduce cellular inflammatory response and improve cellular lipid metabolism by establishing an in vitro model similar to CKD.

CONCLUSIONS

Our results suggest that Klotho exerts protection in CKD, which may be mainly related to the regulation of inflammatory response and lipid metabolism, and it can serve as a potential biomarker for CKD.

Role of fenofibrate in multiple sclerosis

Multiple sclerosis (MS) is the most frequent inflammatory and demyelinating disease of the central nervous system (CNS). The underlying pathophysiology of MS is the destruction of myelin sheath by immune cells. The formation of myelin plaques, inflammation, and injury of neuronal myelin sheath characterizes its neuropathology. MS plaques are multiple focal regions of demyelination disseminated in the brain's white matter, spinal cords, deep grey matter, and cerebral cortex. Fenofibrate is a peroxisome proliferative activated receptor alpha (PPAR-α) that attenuates the inflammatory reactions in MS. Fenofibrate inhibits differentiation of Th17 by inhibiting the expression of pro-inflammatory signaling. According to these findings, this review intended to illuminate the mechanistic immunoinflammatory role of fenofibrate in mitigating MS neuropathology. In conclusion, fenofibrate can attenuate MS neuropathology by modulating different pathways, including oxidative stress, autophagy, mitochondrial dysfunction, inflammatory-signaling pathways, and neuroinflammation.

Effects of polyphenolic maqui (Aristotelia chilensis) extract on the inhibition of NLRP3 inflammasome and activation of mast cells in a mouse model of Crohn's disease-like colitis

Introduction

Crohn's disease (CD) involves activation of mast cells (MC) and NF-кB in parallel with the PPAR-α/NLRP3 inflammasome/IL-1β pathway in the inflamed colon. Whether polyphenols from maqui (Aristotelia chilensis) represent a natural alternative treatment for CD is unclear. Therefore, we used an animal model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced CD-like colitis to investigate protective effects of maqui extract through monitoring NLRP3 inflammasome and MC activation in colon tissue.

Methods

Maqui extract was administered via orogastric route to mice after (post-Treatment group) or prior (pre-Treatment group) to TNBS-induction. Colon pathology was characterized by histoarchitectural imaging, disease activity index (DAI), and assessing NF-кB, p-NF-кB, PPAR-α/NLRP3 expression and IL-1β levels.

Results

Compared to mice treated with TNBS alone administration of anthocyanin-rich maqui extract improved the DAI, colon histoarchitecture and reduced both colon wet-weight and transmural inflammation. Induction with TNBS significantly increased colonic NLPR3 inflammasome activation, while co-treatment with maqui extract (either post- or pre-Treatment) significantly downregulated NLRP3, ASC and caspase-1 levels, which manifested as reduced colonic IL-1β levels. Supplemented maqui extract marginally diminished NF-кB activity in epithelial cells but reached statistical significance in immune cells (as judged by decreased NF-кB phosphorylation). PPAR-α signaling was largely unaffected by Maqui whereas MC infiltration into the colon mucosa and submucosa decreased and their level of degranulation was suppressed.

Conclusion

These outcomes show the post- and pre- Treatment effect of a polyphenolic extract rich in anthocyanins from maqui the acute phase of TNBS- induced CD-like colitis is linked to suppression of the NLRP3 inflammasome and reduced MC responses. These data indicate that maqui extract represents a potential nutraceutical for the treatment of inflammatory bowel disease (IBD).

PPARs/macrophages: A bridge between the inflammatory response and lipid metabolism in autoimmune diseases

Autoimmune diseases (AIDs) are a collection of pathologies that arise from autoimmune reactions and lead to the destruction and damage of the body's tissues and cellular components, ultimately resulting in tissue damage and organ dysfunction. The anti-inflammatory effects of the peroxisome proliferator-activated receptor (PPAR), a pivotal regulator of lipid metabolism, are crucial in the context of AIDs. PPAR mitigates AIDs by modulating macrophage polarization and suppressing the inflammatory response. Numerous studies have demonstrated the crucial involvement of lipid metabolism and phenotypic switching in classically activated (M1)/alternatively activated (M2)-like macrophages in the inflammatory pathway of AIDs. However, the precise mechanism by which PPAR, a critical mediator between of lipid metabolism and macrophage polarization, regulates macrophage polarization remains unclear. This review aimed to clarify the role of PPAR and macrophages in the triangular relationship among AIDs, lipid metabolism, and inflammatory response, and aims to summarize the mechanism of the PPAR-mediated macrophage activation and polarization, which impacts the progression and development of AIDs.

Gamma-glutamyl transferase predicts pemafibrate treatment response in non-alcoholic fatty liver disease

BACKGROUND AND AIM

Pemafibrate, a selective peroxisome proliferator activated receptor α modulator, has been shown to improve liver function among nonalcoholic fatty liver disease (NAFLD) patients with dyslipidemia. The aim of this retrospective study is to identify predictors of pemafibrate efficacy in NAFLD patients.

METHODS

A total of 75 NAFLD patients with dyslipidemia who received pemafibrate twice per day for 48 weeks were enrolled in this study. We used the FibroScan-aspartate aminotransferase (FAST) score as a benchmark for treatment efficacy.

RESULTS

Median FAST score significantly decreased from 0.96 at baseline to 0.93 at week 48 (P < 0.001). Significant improvements in levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), and triglycerides were also noted. The serum level of GGT at baseline was correlated with change in FAST score (r = -0.22, P = 0.049). Changes in AST, ALT, and GGT were positively correlated with change in FAST score (r = 0.71, r = 0.61, and r = 0.38). Multivariate analyses identified age and GGT level at baseline as significantly associated with improvement of FAST score by pemafibrate therapy (odds ratio 1.11, 1.02, respectively). Patients over 50 years of age and with a GGT of 90 IU/L or higher showed significantly greater improvement in the FAST score than other groups.

CONCLUSIONS

Pemafibrate improves the FAST score of NAFLD patients with complicating dyslipidemia, especially in older patients with high GGT level. GGT is useful as an indicator of optimal treatment choice for NAFLD patients with dyslipidemia.

Osteoarthritis: Role of Peroxisome Proliferator-Activated Receptors

Osteoarthritis (OA) represents the foremost degenerative joint disease observed in a clinical context. The escalating issue of population aging significantly exacerbates the prevalence of OA, thereby imposing an immense annual economic burden on societies worldwide. The current therapeutic landscape falls short in offering reliable pharmaceutical interventions and efficient treatment methodologies to tackle this growing problem. However, the scientific community continues to dedicate significant efforts towards advancing OA treatment research. Contemporary studies have discovered that the progression of OA may be slowed through the strategic influence on peroxisome proliferator-activated receptors (PPARs). PPARs are ligand-activated receptors within the nuclear hormone receptor family. The three distinctive subtypes-PPARα, PPARβ/δ, and PPARγ-find expression across a broad range of cellular terminals, thus managing a multitude of intracellular metabolic operations. The activation of PPARγ and PPARα has been shown to efficaciously modulate the NF-κB signaling pathway, AP-1, and other oxidative stress-responsive signaling conduits, leading to the inhibition of inflammatory responses. Furthermore, the activation of PPARγ and PPARα may confer protection to chondrocytes by exerting control over its autophagic behavior. In summation, both PPARγ and PPARα have emerged as promising potential targets for the development of effective OA treatments.

Defensive-lipid droplets: Cellular organelles designed for antimicrobial immunity

Microbes have developed many strategies to subvert host organisms, which, in turn, evolved several innate immune responses. As major lipid storage organelles of eukaryotes, lipid droplets (LDs) are an attractive source of nutrients for invaders. Intracellular viruses, bacteria, and protozoan parasites induce and physically interact with LDs, and the current view is that they "hijack" LDs to draw on substrates for host colonization. This dogma has been challenged by the recent demonstration that LDs are endowed with a protein-mediated antibiotic activity, which is upregulated in response to danger signals and sepsis. Dependence on host nutrients could be a generic "Achilles' heel" of intracellular pathogens and LDs a suitable chokepoint harnessed by innate immunity to organize a front-line defense. Here, we will provide a brief overview of the state of the conflict and discuss potential mechanisms driving the formation of the 'defensive-LDs' functioning as hubs of innate immunity.

Protective effect of Saussurea involucrata polysaccharide against skin dryness induced by ultraviolet radiation

Background: Exposure to ultraviolet B (UVB) radiation can damage the epidermis barrier function and eventually result in skin dryness. At present, little work is being devoted to skin dryness. Searching for active ingredients that can protect the skin against UVB-induced dryness will have scientific significance. Methods: Saussurea involucrata polysaccharide (SIP) has been shown to have significant antioxidant and anti-photodamage effects on the skin following UVB irradiation. To evaluate the effect of SIP on UVB-induced skin dryness ex vivo, SIP-containing hydrogel was applied in a mouse model following exposure to UVB and the levels of histopathological changes, DNA damage, inflammation, keratinocyte differentiation, lipid content were then evaluated. The underlying mechanisms of SIP to protect the cells against UVB induced-dryness were determined in HaCaT cells. Results: SIP was found to lower UVB-induced oxidative stress and DNA damage while increasing keratinocyte differentiation and lipid production. Western blot analysis of UVB-irradiated skin tissue revealed a significant increase in peroxisome proliferator-activated receptor-α (PPAR-α) levels, indicating that the underlying mechanism may be related to PPAR-α signaling pathway activation. Conclusions: By activating the PPAR-α pathway, SIP could alleviate UVB-induced oxidative stress and inhibit the inflammatory response, regulate proliferation and differentiation of keratinocytes, and mitigate lipid synthesis disorder. These findings could provide candidate active ingredients with relatively clear mechanistic actions for the development of skin sunscreen moisturizers.

Expression of cannabinoid (CB1 and CB2) and cannabinoid-related receptors (TRPV1, GPR55, and PPARα) in the synovial membrane of the horse metacarpophalangeal joint

Background

The metacarpophalangeal joint undergoes enormous loading during locomotion and can therefore often become inflamed, potentially resulting in osteoarthritis (OA). There are studies indicating that the endocannabinoid system (ECS) modulates synovium homeostasis, and could be a promising target for OA therapy. Some cannabinoid receptors, which modulate proliferative and secretory responses in joint inflammation, have been functionally identified in human and animal synovial cells.

Objective

To characterize the cellular distribution of the cannabinoid receptors 1 (CB1R) and 2 (CB2R), and the cannabinoid-related receptors transient receptor potential vanilloid type 1 (TRPV1), G protein-related receptor 55 (GPR55) and peroxisome proliferator-activated receptor alpha (PPARα) in the synovial membrane of the metacarpophalangeal joint of the horse.

Animals

The dorsal synovial membranes of 14 equine metacarpophalangeal joints were collected post-mortem from an abattoir.

Materials and methods

The dorsal synovial membranes of 14 equine metacarpophalangeal joints were collected post-mortem from an abattoir. The expression of the CB1R, CB2R, TRPV1, GPR55, and PPARα in synovial tissues was studied using qualitative and quantitative immunofluorescence, and quantitative real-time reverse transcriptase PCR (qRT-PCR). Macrophage-like (MLS) and fibroblast-like (FLS) synoviocytes were identified by means of antibodies directed against IBA1 and vimentin, respectively.

Results

Both the mRNA and protein expression of the CB2R, TRPV1, GPR55, and PPARα were found in the synoviocytes and blood vessels of the metacarpophalangeal joints. The synoviocytes expressed the mRNA and protein of the CB1R in some of the horses investigated, but not in all.

Conclusions and clinical importance

Given the expression of the CB1R, CB2R, TRPV1, GPR55, and PPARα in the synovial elements of the metacarpophalangeal joint, these findings encouraged the development of new studies supporting the use of molecules acting on these receptors to reduce the inflammation during joint inflammation in the horse.

Time-Dependent Oxidative Alterations in Plasma and Lung Tissue after Meconium Aspiration in a Rabbit Model

Aspirated meconium into a newborn's airways induces the transcription of pro-oxidative mediators that cooperate in the pathogenesis of inflammatory changes and may negatively affect the commonly used exogenous surfactant therapy. However, inflammation is not treated at present, nor is the time dependence of oxidative damage known. The aim of our study was to describe the time course of oxidative stress marker production during meconium aspiration syndrome (MAS) and its relationship to leukocyte infiltration. New Zealand rabbits were instilled with saline or meconium suspension and ventilated for 5.5 h. Respiratory parameters were recorded and blood samples were taken before meconium application and in time intervals of 15 and 30 min, 1.0, 1.5, 3.5 and 5.5 h after application to evaluate oxidative markers and differential leukocytes count. Meconium aspiration led to a worsening of respiratory parameters and a decrease in leukocytes in the first 15 min. Changes in leukocytes were correlated both with nitrotyrosine (3NT) levels and thiobarbituric acid reactive substance (TBARS) levels, with the latter also related to changes in neutrophil count. The production of 3NT and TBARS increased in 1.5 and 3.5 h, respectively, in different ways, suggesting more than one source of oxidative agents and a potential risk of exogenous surfactant inactivation in a short time. We observed that MAS triggered neutrophil migration to the alveolar space and activation, as shown by the increased expression of pro-inflammatory cytokines and generation of indicators of oxidative damage to proteins and lipids during the time period when iNOS and NO metabolites were released.

A randomized clinical trial of lipid metabolism modulation with fenofibrate for acute coronavirus disease 2019

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cytotoxicity may involve inhibition of peroxisome proliferator-activated receptor alpha. Fenofibrate activates peroxisome proliferator-activated receptor alpha and inhibits SARS-CoV-2 replication in vitro. Whether fenofibrate can be used to treat coronavirus disease 2019 (COVID-19) infection in humans remains unknown. Here, we randomly assigned inpatients and outpatients with COVID-19 within 14 d of symptom onset to 145 mg of oral fenofibrate nanocrystal formulation versus placebo for 10 d, in a double-blinded fashion. The primary endpoint was a severity score whereby participants were ranked across hierarchical tiers incorporating time to death, mechanical ventilation duration, oxygenation, hospitalization and symptom severity and duration. In total, 701 participants were randomized to fenofibrate (n = 351) or placebo (n = 350). The mean age of participants was 49 ± 16 years, 330 (47%) were female, mean body mass index was 28 ± 6 kg/m2 and 102 (15%) had diabetes. Death occurred in 41 participants. Compared with placebo, fenofibrate had no effect on the primary endpoint. The median (interquartile range) rank in the placebo arm was 347 (172, 453) versus 345 (175, 453) in the fenofibrate arm (P = 0.819). There was no difference in secondary and exploratory endpoints, including all-cause death, across arms. There were 61 (17%) adverse events in the placebo arm compared with 46 (13%) in the fenofibrate arm, with slightly higher incidence of gastrointestinal side effects in the fenofibrate group. Overall, among patients with COVID-19, fenofibrate has no significant effect on various clinically relevant outcomes ( NCT04517396 ).

WY-14643 attenuates lipid deposition via activation of the PPARα/CPT1A axis by targeting Gly335 to inhibit cell proliferation and migration in ccRCC

Background

Histologically, cytoplasmic deposits of lipids and glycogen are common in clear cell renal cell carcinoma (ccRCC). Owing to the significance of lipid deposition in ccRCC, numerous trials targeting lipid metabolism have shown certain therapeutic potential. The agonism of peroxisome proliferator-activated receptor-α (PPARα) via ligands, including WY-14,643, has been considered a promising intervention for cancers.

Methods

First, the effects of WY-14,643 on malignant behaviors were investigated in ccRCC in vitro. After RNA sequencing, the changes in lipid metabolism, especially neutral lipids and glycerol, were further evaluated. Finally, the underlying mechanisms were revealed.

Results

Phenotypically, the proliferation and migration of ccRCC cells treated with WY-14,643 were significantly inhibited in vitro. A theoretical functional mechanism was proposed in ccRCC: WY-14,643 mediates lipid consumption by recognizing carnitine palmitoyltransferase 1 A (CPT1A). Activation of PPARα using WY-14,643 reduces lipid deposition by increasing the CPT1A level, which also suppresses the NF-κB signaling pathway. Spatially, WY-14,643 binds and activates PPARα by targeting Gly335.

Conclusion

Overall, WY-14,643 suppresses the biological behaviors of ccRCC in terms of cell proliferation, migration, and cell cycle arrest. Furthermore, its anticancer properties are mediated by the inhibition of lipid accumulation, at least in part, through the PPARα/CPT1A axis by targeting Gly335, as part of the process, NF-κB signaling is also suppressed. Pharmacological activation of PPARα might offer a new treatment option for ccRCC.

Swimming exercise activates peroxisome proliferator-activated receptor-alpha and mitigates age-related renal fibrosis in rats

Aging results in progressive decline of renal function as well as histological alterations including glomerulosclerosis and interstitial fibrosis. The objective of current study was to test the benefits of moderate swimming exercise in aged rats on renal function and structure and investigate its molecular mechanisms. Aged rats of 21-months old were given moderate swimming exercise for 12 weeks. Swimming exercise in aged rats led to reduced plasma levels of creatinine and blood urea nitrogen. Periodic acid-Schiff staining results revealed reduced renal injury scores in aged rats after swimming exercise. Swimming exercise in aged rats mitigated renal fibrosis and downregulated the mRNA expression of Acta2, Fn, Col1a, Col4a, and Tgfb1 in kidneys. Swimming exercise in aged rats attenuated lipid accumulation and reduced levels of triglyceride in kidneys. Swimming exercise in aged rats abated oxidative stress, evidenced by reduced MDA levels and increased MnSOD activities in kidneys. Swimming exercise in aged rats inhibited NF-κB activities and reduced renal expression of pro-inflammatory cytokines including MCP-1, IL-1β and IL-6. Mechanistically, swimming exercise restored mRNA and protein expression of PPAR-α in kidney of aged rats. Furthermore, swimming exercise in aged rats increased expression of PPAR-α-targeting microRNAs including miR-21 and miR-34a. Collectively, swimming exercise activated PPAR-α, which partly explained the benefits of moderate swimming exercise in aging kidneys.

An Artemisia ordosica extract: Effects on growth performance, immune, and inflammatory response in lipopolysaccharide-challenged broilers

Artemisia ordosica has been applied as a traditional Chinese/Mongolian medicine for treating csertain inflammatory ailments. This study was conducted to investigate the effect of Artemisia ordosica alcohol extract (AOAE) supplemented in diets on growth performance, immune, and inflammatory response in lipopolysaccharide (LPS)-challenged broilers. A total of 240 one-day-old Arbor Acre male broilers were randomly allotted into 5 groups with 6 replicates (n = 8), which were basal diet group (CON), LPS-challenge and basal diet group (LPS), LPS-challenge and the basal diet added with low (500 mg/kg), middle (750 mg/kg), and high (1,000 mg/kg) dose of AOAE groups (AOAE-L, AOAE-M, and AOAE-H), respectively. On d 16, 18, 20, 22, 24, 26, and 28, all broilers were injected intra-abdominally either with LPS or an equivalent amount of saline. Results showed that dietary AOAE alleviated the LPS-induced decrease in average daily gain and average daily feed intake in the broilers (P < 0.05). Dietary AOAE supplementation reversed the increased spleen index and the decreased bursa index in LPS-challenged broilers (P < 0.05). Moreover, feeding AOAE could mitigate the elevation of IL-1β in serum, liver, and spleen, IL-2 in serum and liver, IL-6 in serum and spleen, and the decrease of IgG in spleen, IgM in serum, liver, and spleen, and IL-4 in serum of the LPS-challenged broilers (P < 0.05). This study also showed that AOAE supplementation alleviated the increase of mRNA expression of TLR4, MyD88, TRAF6, NF-κB p65, NF-κB p50, IL-1β, and IL-6, and the decrease of gene expression of IκBα and PPARγ in liver and/or spleen of broilers challenged by LPS (P < 0.05). We speculated that AOAE administration could effectively alleviate LPS-induced inflammation via decreasing over-production of proinflammatory cytokines, ultimately relieving the growth inhibition of broilers caused by LPS. In conclusion, 1,000 mg/kg AOAE has a strong capacity to enhance immunity and inhibit inflammation, and can be used as a potential novel feed additive with applications in treating inflammation-related diseases and bacterial infection in broilers.

A Randomized Trial of Lipid Metabolism Modulation with Fenofibrate for Acute Coronavirus Disease 2019

Background Abnormal cellular lipid metabolism appears to underlie SARS-CoV-2 cytotoxicity and may involve inhibition of peroxisome proliferator activated receptor alpha (PPARα). Fenofibrate, a PPAR-α activator, modulates cellular lipid metabolism. Fenofibric acid has also been shown to affect the dimerization of angiotensin-converting enzyme 2, the cellular receptor for SARS-CoV-2. Fenofibrate and fenofibric acid have been shown to inhibit SARS-CoV-2 replication in cell culture systems in vitro . Methods We randomly assigned 701 participants with COVID-19 within 14 days of symptom onset to 145 mg of fenofibrate (nanocrystal formulation with dose adjustment for renal function or dose-equivalent preparations of micronized fenofibrate or fenofibric acid) vs. placebo for 10 days, in a double-blinded fashion. The primary endpoint was a ranked severity score in which participants were ranked across hierarchical tiers incorporating time to death, duration of mechanical ventilation, oxygenation parameters, subsequent hospitalizations and symptom severity and duration. ClinicalTrials.gov registration: NCT04517396. Findings: Mean age of participants was 49 ± 16 years, 330 (47%) were female, mean BMI was 28 ± 6 kg/m 2 , and 102 (15%) had diabetes mellitus. A total of 41 deaths occurred. Compared with placebo, fenofibrate administration had no effect on the primary endpoint. The median (interquartile range [IQR]) rank in the placebo arm was 347 (172, 453) vs. 345 (175, 453) in the fenofibrate arm (P = 0.819). There was no difference in various secondary and exploratory endpoints, including all-cause death, across randomization arms. These results were highly consistent across pre-specified sensitivity and subgroup analyses. Conclusion Among patients with COVID-19, fenofibrate has no significant effect on various clinically relevant outcomes.

PPARα: A potential therapeutic target of cholestasis

The accumulation of bile acids in the liver leads to the development of cholestasis and hepatocyte injury. Nuclear receptors control the synthesis and transport of bile acids in the liver. Among them, the farnesoid X receptor (FXR) is the most common receptor studied in treating cholestasis. The activation of this receptor can reduce the amount of bile acid synthesis and decrease the bile acid content in the liver, alleviating cholestasis. Ursodeoxycholic acid (UDCA) and obeticholic acid (OCA) have a FXR excitatory effect, but the unresponsiveness of some patients and the side effect of pruritus seriously affect the results of UDCA or OCA treatment. The activator of peroxisome proliferator-activated receptor alpha (PPARα) has emerged as a new target for controlling the synthesis and transport of bile acids during cholestasis. Moreover, the anti-inflammatory effect of PPARα can effectively reduce cholestatic liver injury, thereby improving patients’ physiological status. Here, we will focus on the function of PPARα and its involvement in the regulation of bile acid transport and metabolism. In addition, the anti-inflammatory effects of PPARα will be discussed in some detail. Finally, we will discuss the application of PPARα agonists for cholestatic liver disorders.

Lipid Behavior in Metabolic Syndrome Pathophysiology

Undeniably, lipid plays an extremely important role in the homeostasis balance since lipid contributes to the regulation of the metabolic processes. The metabolic syndrome pathogenesis is multi-pathway that composes neurohormonal disorders, endothelial cell dysfunction, metabolic disturbance, genetic predisposition, in addition to gut commensal microbiota. The heterogenicity of the possible mechanisms gives the metabolic syndrome its complexity and limitation of therapeutic accesses. The main pathological link is that lipid contributes to the emergence of metabolic syndrome via central obesity and visceral obesity that consequently lead to oxidative stress and chronic inflammatory response promotion. Physiologically, a balance is kept between the adiponectin and adipokines levels to maintain the lipid level in the organism. Clinically, extremely important to define the borders of the lipid level in which the pathogenesis of the metabolic syndrome is reversible, otherwise it will be accompanied by irreversible complications and sequelae of the metabolic syndrome (cardiovascular, insulin resistance). The present paper is dedicated to providing novel insights into the role of lipid in the development of metabolic syndrome; hence dyslipidemia is the initiator of insulin resistance syndrome (metabolic syndrome).

The Emerging Role of Non-Coding RNAs in Osteoarthritis

Osteoarthritis (OS) is the most frequent degenerative condition in the joints, disabling many adults. Several abnormalities in the articular cartilage, subchondral bone, synovial tissue, and meniscus have been detected in the course of OA. Destruction of articular cartilage, the formation of osteophytes, subchondral sclerosis, and hyperplasia of synovial tissue are hallmarks of OA. More recently, several investigations have underscored the regulatory roles of non-coding RNAs (ncRNAs) in OA development. Different classes of non-coding RNAs, including long ncRNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), have been reported to affect the development of OA. The expression level of these transcripts has also been used as diagnostic tools in OA. In the present article, we aimed at reporting the role of these transcripts in this process. We need to give a specific angle on the pathology to provide meaningful thoughts on it.

Regulation of Key Genes for Milk Fat Synthesis in Ruminants

Milk fat is the most important and energy-rich substance in milk and plays an important role in the metabolism of nutrients during human growth and development. It is mainly used in the production of butter and yogurt. Milk fat not only affects the flavor and nutritional value of milk, but also is the main target trait of ruminant breeding. There are many key genes involve in ruminant milk fat synthesis, including ACSS2, FASN, ACACA, CD36, ACSL, SLC27A, FABP3, SCD, GPAM, AGPAT, LPIN, DGAT1, PLIN2, XDH, and BTN1A1. Taking the de novo synthesis of fatty acids (FA) and intaking of long-chain fatty acids (LCFA) in blood to the end of lipid droplet secretion as the mainline, this manuscript elucidates the complex regulation model of key genes in mammary epithelial cells (MECs) in ruminant milk fat synthesis, and constructs the whole regulatory network of milk fat synthesis, to provide valuable theoretical basis and research ideas for the study of milk fat regulation mechanism of ruminants.

Peroxisome Proliferator-Activated Receptors (PPARs) and Oxidative Stress in Physiological Conditions and in Cancer

Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear hormone receptor superfamily. Originally described as “orphan nuclear receptors”, they can bind both natural and synthetic ligands acting as agonists or antagonists. In humans three subtypes, PPARα, β/δ, γ, are encoded by different genes, show tissue-specific expression patterns, and contribute to the regulation of lipid and carbohydrate metabolisms, of different cell functions, including proliferation, death, differentiation, and of processes, as inflammation, angiogenesis, immune response. The PPAR ability in increasing the expression of various antioxidant genes and decreasing the synthesis of pro-inflammatory mediators, makes them be considered among the most important regulators of the cellular response to oxidative stress conditions. Based on the multiplicity of physiological effects, PPAR involvement in cancer development and progression has attracted great scientific interest with the aim to describe changes occurring in their expression in cancer cells, and to investigate the correlation with some characteristics of cancer phenotype, including increased proliferation, decreased susceptibility to apoptosis, malignancy degree and onset of resistance to anticancer drugs. This review focuses on mechanisms underlying the antioxidant and anti-inflammatory properties of PPARs in physiological conditions, and on the reported beneficial effects of PPAR activation in cancer.

Exploring the Mechanism of Resveratrol in Reducing the Soft Tissue Damage of Osteoarthritis Based on Network Pharmacology and Experimental Pharmacology

AIM

To explore the mechanism of resveratrol in reducing the soft tissue damage of osteoarthritis (OA) based on network pharmacology.

METHODS

Pharmmapper was used to predict the target of resveratrol, OMIM and Genecards were used to collect OA-related disease genes, and David ver 6.8 was used for enrichment analysis. Then, animal experiments were carried out for verification. The rat OA model was established and the rats were randomly divided into 4 groups: model group, resveratrol low-dose group, resveratrol high-dose group, and blank control group for follow-up experiments. Hematoxylin-eosin (HE) staining was used to detect the degree of pathological damage of rat bones and joints. Enzyme-linked immunosorbent assay (ELISA) was used for the content of inflammatory factors. Western blot was used to detect the expression of Toll-like receptor 4 (TLR4), Myeloid differentiation factor 88 (MyD88), nuclear factor kappa B protein (NF-κB), cysteine protease-9 (CASP-9), Bcl-2 protein, and Bax protein.

RESULTS

Through network pharmacological analysis, this study found that resveratrol may regulate the TLR4 signaling pathway, PI3K-Akt signaling pathway, FoxO signaling pathway, Osteoclast differentiation, Rheumatoid arthritis, etc. Animal experiments showed that compared with the model group, the pathological damage of bone and joint in the resveratrol low-dose and high-dose groups was significantly improved. Compared with the model group, the serum levels of IL-1beta, IL-6, IL-17, TNF-α, and MCP-1 in the resveratrol low-dose and high-dose groups were significantly reduced (P < 0.05); protein levels of TLR-4, MyD88, and NF-κB p65 were significantly reduced (P < 0.05); caspase-9 and Bax protein levels were significantly reduced (P < 0.05), and Bcl-2 was significantly increased (P < 0.05).

CONCLUSION

Resveratrol may inhibit the activation of the TLR4-mediated NF-κB signaling pathway and has a repairing effect on soft tissue damage in OA.

Anti-inflammatory activity of palmitoylethanolamide ameliorates osteoarthritis induced by monosodium iodoacetate in Sprague-Dawley rats

Novel treatment strategies are urgently required for osteoarthritis (OA). Palmitoylethanolamide (PEA) is a naturally occurring fatty acid amide with analgesic and anti-inflammatory effects. We aimed to examine its effect on OA and elucidate the molecular mechanism of actions in monosodium iodoacetate (MIA)-induced OA Sprague–Dawley rats. The experimental animals were divided into normal control group (injected with saline + treated with phosphate-buffered saline (PBS), NOR), control group (injected with MIA + treated with PBS, CON), 50 or 100 mg/kg body weight (BW)/day PEA-treated group (injected with MIA + treated with 50 or 100 mg of PEA/kg BW/day, PEA50 or PEA100), and positive control group (injected with MIA + treated with 6 mg of diclofenac/kg BW/day, DiC). The changes in blood parameters, body parameters, gene expression of inflammatory mediators and cytokines, knee thickness, and joint tissue were observed. Oral administration of PEA had no adverse effects on the BW, liver, or kidneys. PEA reduced knee joint swelling and cartilage degradation in MIA-induced OA rats. The serum levels of leukotriene B4, nitric oxide, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and prostaglandin E2 considerably reduced in the PEA100 group compared with those in the CON group. In the synovia of knee joints, the mRNA expression of iNOS, 5-Lox, Cox-2, Il-1β, Tnf-α, and Mmp-2, -3, -9, and -13 apparently increased with MIA administration. Meanwhile, Timp-1 mRNA expression apparently decreased in the CON group but increased to the normal level with PEA treatment. Thus, PEA can be an effective therapeutic agent for OA.

Human bone mesenchymal stem cells-derived exosomal miRNA-361-5p alleviates osteoarthritis by downregulating DDX20 and inactivating the NF-κB signaling pathway

Osteoarthritis (OA) is a chronic disease featured by joint hyperplasia, deterioration of articular cartilage, and progressive degeneration. Abnormal expression of microRNAs (miRNAs) has been found to be implicated in the pathological process of OA. In this study, the role of miR-361-5p transferred by exosomes derived from human bone mesenchymal stem cells (hBMSCs) in OA was investigated. The expression of Asp-Glu-Ala-Asp-box polypeptide 20 (DDX20) and miR-361-5p in interleukin-1β (IL-1β)-treated chondrocytes was determined by reverse transcription quantitative polymerase chain reaction. DDX20 was knocked down by transfection of short hairpin RNA targeting DDX20, and the effects of DDX20 downregulation on IL-1β-induced damage of chondrocytes were detected. The interaction between DDX20 and miR-361-5p was tested by luciferase report assay. hBMSCs-derived exosomes loaded with miR-361-5p were co-incubated with chondrocytes followed by detection of cell viability, proliferation and inflammatory response. An OA rat model was established to further explore the role of miR-361-5p in vivo. Western blot, luciferase reporter and immunofluorescence staining assays were used to evaluate the activation of the nuclear factor kappa-B (NF-κB) signaling pathway. We found that DDX20 was upregulated, while miR-361-5p was underexpressed in IL-1β-treated chondrocytes. Downregulation of DDX20 inhibits levels of matrix metalloproteinases (MMPs) and suppresses inflammation induced by IL-1β. Mechanistically, miR-361-5p was verified to directly target DDX20. In addition, hBMSC-derived exosomes-transferred miR-361-5p alleviates chondrocyte damage and inhibits the NF-κB signaling pathway via targeting DDX20. Inhibition of NF-κB signaling reverses the effect of overexpressed DDX20 on IL-1β-induced chondrocyte damage. Moreover, exosomal miR-361-5p alleviates OA damage in vivo. Overall, hBMSC-derived exosomal miR-361-5p alleviates OA damage by targeting DDX20 and inactivating the NF-κB signaling pathway.

Lipopolysaccharides induce a RAGE-mediated sensitization of sensory neurons and fluid hypersecretion in the upper airways

Thoracic dorsal root ganglia (tDRG) contribute to fluid secretion in the upper airways. Inflammation potentiates DRG responses, but the mechanisms remain under investigation. The receptor for advanced glycation end-products (RAGE) underlies potentiation of DRG responses in pain pathologies; however, its role in other sensory modalities is less understood. We hypothesize that RAGE contributes to electrophysiological and biochemical changes in tDRGs during inflammation. We used tDRGs and tracheas from wild types (WT), RAGE knock-out (RAGE-KO), and with the RAGE antagonist FPS-ZM1, and exposed them to lipopolysaccharides (LPS). We studied: capsaicin (CAP)-evoked currents and action potentials (AP), tracheal submucosal gland secretion, RAGE expression and downstream pathways. In WT neurons, LPS increased CAP-evoked currents and AP generation, and it caused submucosal gland hypersecretion in tracheas from WT mice exposed to LPS. In contrast, LPS had no effect on tDRG excitability or gland secretion in RAGE-KO mice or mice treated with FPS-ZM1. LPS upregulated full-length RAGE (encoded by Tv1-RAGE) and downregulated a soluble (sRAGE) splice variant (encoded by MmusRAGEv4) in tDRG neurons. These data suggest that sensitization of tDRG neurons contributes to hypersecretion in the upper airways during inflammation. And at least two RAGE variants may be involved in these effects of LPS.

Impact of Circulating N-Acylethanolamine Levels with Clinical and Laboratory End Points in Hemodialysis Patients

BACKGROUND

Patients with ESRD on maintenance hemodialysis (MHD) are particularly susceptible to dysregulation of energy metabolism, which may manifest as protein energy wasting and cachexia. In recent years, the endocannabinoid system has been shown to play an important role in energy metabolism with potential relevance in ESRD. N-acylethanolamines are a class of fatty acid amides which include the major endocannabinoid ligand, anandamide, and the endogenous peroxisome proliferator-activated receptor-α agonists, oleoylethanolamide (OEA) and palmitoylethanolamide (PEA).

METHODS

Serum concentrations of OEA and PEA were measured in MHD patients and their correlations with various clinical/laboratory indices were examined. Secondarily, we evaluated the association of circulating PEA and OEA levels with 12-month all-cause mortality.

RESULTS

Both serum OEA and PEA levels positively correlated with high-density lipoprotein-cholesterol levels and negatively correlated with body fat and body anthropometric measures. Serum OEA levels correlated positively with serum interleukin-6 (IL-6) (rho = 0.19; p = 0.004). Serum PEA and IL-6 showed a similar but nonsignificant trend (rho = 0.12; p = 0.07). Restricted cubic spline analyses showed that increasing serum OEA and PEA both trended toward higher mortality risk, and these associations were statistically significant for PEA (PEA ≥4.7 pmol/mL; reference: PEA <4.7 pmol/mL) after adjustments in a Cox model (hazard ratio 2.99; 95% confidence interval 1.04, 8.64).

CONCLUSIONS

In MHD patients, OEA and PEA are significantly correlated with variables related to lipid metabolism and body mass. Additionally, higher serum levels of PEA are associated with mortality risk. Future studies are needed to examine the potential mechanisms responsible for these findings and their clinical implications.

NOD2 induces VCAM-1 and ET-1 gene expression via NF-κB in human umbilical vein endothelial cells with muramyl dipeptide stimulation

OBJECTIVES

Endothelial dysfunction is involved in various aspects of vascular biology and different stages of cardiovascular diseases (CVDs). Nucleotide-binding oligomerization domain-containing protein (NOD) 2, a pivotal innate immune receptor for muramyl dipeptide (MDP), has been reported to be a central regulator in CVDs. Previously, we reported that NOD2 played a leading role in MDP-triggered oxidative stress in endothelial cells (ECs). However, whether NOD2 participates in the regulatory mechanism of vascular cell adhesion molecule‑1 (VCAM-1) and endothelin‑1 (ET-1) expression was not elucidated.

METHODS

Human umbilical vein endothelial cells (HUVECs) were stimulated with MDP for 12 h. mRNA expression of VCAM‑1 and ET‑1 was detected using real time polymerase chain reaction (PCR). Scrambled control small interfering RNA (siRNA) and NOD2 siRNA were transfected into HUVECs using Lipofectamine 2000 reagent (Invitrogen, Waltham, MA, USA). Furthermore, pyrrolidine dithiocarbamate was adopted to investigate the effect of nuclear factor κB (NF-κB) on NOD2-mediated VCAM‑1 and ET‑1 gene expression in MDP-treated HUVECs.

RESULTS

Data showed that MDP significantly increased VCAM‑1 and ET‑1 mRNA expression, which was dependent on NOD2. In addition, NF-κB inhibition suppressed NOD2-mediated gene expression of VCAM‑1 and ET‑1.

CONCLUSION

Collectively, we confirmed NOD2 aggravated VCAM‑1 and ET‑1 gene expression through NF-κB in HUVECs treated with MDP.

Role of peroxisome proliferator-activated receptor-α on the synthesis of monounsaturated fatty acids in goat mammary epithelial cells

A key member of the nuclear receptor superfamily is the peroxisome proliferator-activated receptor alpha (PPARA) isoform, which in nonruminants is closely associated with fatty acid oxidation. Whether PPARA plays a role in milk fatty acid synthesis in ruminants is unknown. The main objective of the present study was to use primary goat mammary epithelial cells (GMEC) to activate PPARA via the agonist WY-14643 (WY) or to silence it via transfection of small-interfering RNA (siRNA). Three copies of the peroxisome proliferator-activated receptor response element (PPRE) contained in a luciferase reporter vector were transfected into GMEC followed by incubation with WY at 0, 10, 20, 30, 50, or 100 µM. A dose of 50 µM WY was most effective at activating PPRE without influencing PPARA mRNA abundance. Transfecting siRNA targeting PPARA decreased its mRNA abundance to 20% and protein level to 50% of basal levels. Use of WY upregulated FASN, SCD1, ACSL1, DGAT1, FABP4, and CD36 (1.1-, 1.5-, 2-, 1.4-, 1.5-, and 5-fold, respectively), but downregulated DGAT2 and PGC1A (-20% and -40%, respectively) abundance. In contrast, triacylglycerol concentration decreased and the content and desaturation index of C16:1 and C18:1 increased. Thus, activation of PPARA via WY appeared to channel fatty acids away from esterification. Knockdown of PPARA via siRNA downregulated ACACA, SCD1, AGPAT6, CD36, HSL, and SREBF1 (-43%, -67%, -16%, -56%, -26%, and -29%, respectively), but upregulated ACSL1, DGAT2, FABP3, and PGC1A (2-, 1.4-, 1.3-, and 2.5-fold, respectively) mRNA abundance. A decrease in the content and desaturation index of C16:1 and C18:1 coupled with an increase in triacylglycerol content accompanied those effects at the mRNA level. Overall, data suggest that PPARA could promote the synthesis of MUFA in GMEC through its effects on mRNA abundance of genes related to fatty acid synthesis, oxidation, transport, and triacylglycerol synthesis.

The emerging role of fibroblast-like synoviocytes-mediated synovitis in osteoarthritis: An update

Osteoarthritis (OA), the most ubiquitous degenerative disease affecting the entire joint, is characterized by cartilage degradation and synovial inflammation. Although the pathogenesis of OA remains poorly understood, synovial inflammation is known to play an important role in OA development. However, studies on OA pathophysiology have focused more on cartilage degeneration and osteophytes, rather than on the inflamed and thickened synovium. Fibroblast-like synoviocytes (FLS) produce a series of pro-inflammatory regulators, such as inflammatory cytokines, nitric oxide (NO) and prostaglandin E₂ (PGE₂ ). These regulators are positively associated with the clinical symptoms of OA, such as inflammatory pain, joint swelling and disease development. A better understanding of the inflammatory immune response in OA-FLS could provide a novel approach to comprehensive treatment strategies for OA. Here, we have summarized recently published literatures referring to epigenetic modifications, activated signalling pathways and inflammation-associated factors that are involved in OA-FLS-mediated inflammation. In addition, the current related clinical trials and future perspectives were also summarized.

Effects of nitric oxide donor on the lung functions in a saline lavage-induced model of ARDS

Acute respiratory distress syndrome (ARDS) is characterized by acute hypoxemia, neutrophil-mediated inflammation, and lung edema formation. Whereas lung damage might be alleviated by nitric oxide (NO), goal of this study was to evaluate if intratracheal NO donor S-nitroso-N-acetylpenicillamine (SNAP) can positively influence the lung functions in experimental model of ARDS. New Zealand rabbits with respiratory failure induced by saline lavage (30 ml/kg, 9+/-3 times) were divided into: ARDS group without therapy, ARDS group treated with SNAP (7 mg/kg i.t.), and healthy Control group. During 5 h of ventilation, respiratory parameters (blood gases, ventilatory pressures) were estimated. After anesthetics overdosing, left lung was saline-lavaged and cell count, cell viability and protein content in bronchoalveolar lavage fluid (BALF) were measured. Right lung tissue was used for estimation of wet/dry weight ratio, concentration of NO metabolites, and histomorphological investigation. Repetitive lung lavage induced lung injury, worsened gas exchange, and damaged alveolar-capillary membrane. Administration of SNAP reduced cell count in BALF, lung edema formation, NO metabolites, and histopathological signs of injury, and improved respiratory parameters. Treatment with intratracheal SNAP alleviated lung injury and edema and improved lung functions in a saline-lavaged model of ARDS suggesting a potential of NO donors also for patients with ARDS.

Tripartite Motif-Containing 46 Promotes Viability and Inhibits Apoptosis of Osteosarcoma Cells by Activating NF-B Signaling Through Ubiquitination of PPAR

Osteosarcoma (OS), the most common bone cancer, causes high morbidity in children and young adults. TRIM46 is a member of the family of tripartite motif (TRIM)-containing proteins that serve as important regulators of tumorigenesis. Here we investigate the possible role of TRIM46 in OS and the underlying molecular mechanism. We report an increase in the expression of TRIM46 in OS and its association with tumor size, Enneking’s stage, and patient prognosis. TRIM46 knockdown inhibits OS cell viability and cell cycle progression and induces apoptosis, while TRIM46 overexpression exerts inverse effects, which are inhibited by peroxisome proliferator-activated receptor alpha (PPARα) overexpression and the nuclear factor kappa B (NF-κB) inhibitor, pyrrolidine dithiocarbamate (PDTC). Furthermore, TRIM46 negatively regulates PPARα expression via ubiquitination-mediated protein degradation and modification. PPARα overexpression also inactivates NF-κB signaling and NF-κB promoter activity in OS cells overexpressing TRIM46. Moreover, TRIM46 knockdown inhibits tumor growth and induces apoptosis of OS cells in vivo. TRIM46 acts as an oncogene in OS by interacting with and ubiquitinating PPARα, resulting in the activation of NF-κB signaling pathway. Thus, TRIM46 may be a potential biomarker of carcinogenesis.

Peroxisome proliferator-activated receptor α (PPARα)-dependent regulation of fibroblast growth factor 23 (FGF23)

Bone cells secrete fibroblast growth factor 23 (FGF23), a hormone that inhibits the synthesis of active vitamin D (1,25(OH)₂D₃) and induces phosphate excretion in the kidney. In addition, it exerts paracrine effects on other cells including hepatocytes, cardiomyocytes, and immune cells. The production of FGF23 is controlled by different factors including parathyroid hormone, 1,25(OH)₂D₃, alimentary phosphate, insulin, inflammation, and AMP-dependent kinase (AMPK) regulation of store-operated Ca²⁺ entry (SOCE). Peroxisome proliferator-activated receptor α (PPARα) is a transcription factor with anti-inflammatory properties regulating lipid metabolism. Fibrates, PPARα agonists, are used in the treatment of dyslipidemia and activate AMPK. Here, we tested whether PPARα is a regulator of FGF23. Fgf23 gene expression was analyzed in UMR106 rat osteoblast-like cells by qRT-PCR, AMPK phosphorylation by Western blotting, and SOCE assessed by fluorescence optics. PPARα agonists fenofibrate and WY-14643 suppressed, whereas PPARα antagonist GW6471 and siRNA-mediated knockdown of PPARα induced Fgf23 gene expression. Fenofibrate induced AMPK activity in UMR106 cells and lowered SOCE. AMPK inhibitor compound C abrogated the PPARα effect on FGF23 in large part. Silencing of Orai-1 resulted in failure of PPARα to significantly influence Fgf23 expression. Taken together, PPARα is a potent regulator of FGF23. PPARα agonists down-regulate FGF23 formation at least in part through AMPK-mediated suppression of SOCE.

The Role of Inflammation in the Pathogenesis of Osteoarthritis

A joint is the point of connection between two bones in our body. Inflammation of the joint leads to several diseases, including osteoarthritis, which is the concern of this review. Osteoarthritis is a common chronic debilitating joint disease mainly affecting the elderly. Several studies showed that inflammation triggered by factors like biomechanical stress is involved in the development of osteoarthritis. This stimulates the release of early-stage inflammatory cytokines like interleukin-1 beta (IL-1β), which in turn induces the activation of signaling pathways, such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), phosphoinositide 3-kinase/protein kinase B (PI3K/AKT), and mitogen-activated protein kinase (MAPK). These events, in turn, generate more inflammatory molecules. Subsequently, collagenase like matrix metalloproteinases-13 (MMP-13) will degrade the extracellular matrix. As a result, anatomical and physiological functions of the joint are altered. This review is aimed at summarizing the previous studies highlighting the involvement of inflammation in the pathogenesis of osteoarthritis.

Saikosaponin a attenuates hyperlipidemic pancreatitis in rats via the PPAR-γ/NF-κB signaling pathway

The therapeutic effect of saikosaponin a (SSa) on hyperlipidemic pancreatitis (HP) is not completely understood. The aim of the present study was to investigate the therapeutic effect and the underlying mechanism of SSa using a rat model of HP. Following successful establishment of the HP rat model, different doses of SSa (low dose group, 10 mg/kg or high dose group, 20 mg/kg) were administrated. Histopathological examination, the wet/dry (W/D) ratio and myeloperoxidase (MPO) activity of the pancreatic tissues were assessed. The lipid, amylase (AMY), lipase and proinflammatory cytokine profiles in serum, as well as the expression of peroxisome proliferator-activated receptor (PPAR)-γ and the NF-κB signaling pathway-related proteins in pancreatic tissues were evaluated. The results showed that SSa effectively attenuated pancreatic pathological injury and reduced both the W/D ratio and MPO activity compared to the HP model rats. SSa also improved lipid metabolism by significantly decreasing the serum levels of total cholesterol and triglycerides (P<0.05). Following the administration of SSa, the activity of AMY and lipase, as well as the levels of the proinflammatory cytokines tumor necrosis factor-α, interleukin (IL)-1β and IL-6 were reduced, particularly in the high dosage group (P<0.05). Furthermore, SSa activated PPAR-γ expression and suppressed the NF-κB signaling pathway in pancreatic tissues. The present study suggested that SSa attenuated HP in rats by increasing lipid metabolism and inhibiting the release of proinflammatory cytokines via the NF-κB inflammatory pathway. The results from the present study indicated that SSa might be a promising therapeutic agent for the treatment of HP.

Peroxisome Proliferator-Activated Receptors as a Therapeutic Target in Asthma

The complexity of the pathogenetic mechanisms of the development of chronic inflammation in asthma determines its heterogeneity and insufficient treatment effectiveness. Nuclear transcription factors, which include peroxisome proliferator-activated receptors, that is, PPARs, play an important role in the regulation of initiation and resolution of the inflammatory process. The ability of PPARs to modulate not only lipid homeostasis but also the activity of the inflammatory response makes them an important pathogenetic target in asthma therapy. At present, special attention is focused on natural (polyunsaturated fatty acids (PUFAs), endocannabinoids, and eicosanoids) and synthetic (fibrates, thiazolidinediones) PPAR ligands and the study of signaling mechanisms involved in the implementation of their anti-inflammatory effects in asthma. This review summarizes current views on the structure and function of PPARs, as well as their participation in the pathogenesis of chronic inflammation in asthma. The potential use of PPAR ligands as therapeutic agents for treating asthma is under discussion.

Lipid-Induced Mechanisms of Metabolic Syndrome

Metabolic syndrome (MetS) has a worldwide tendency to increase and depends on many components, which explains the complexity of diagnosis, approaches to the prevention, and treatment of this pathology. Insulin resistance (IR) is the crucial cause of the MetS pathogenesis, which develops against the background of abdominal obesity. In light of recent evidence, it has been shown that lipids, especially fatty acids (FAs), are important signaling molecules that regulate the signaling pathways of insulin and inflammatory mediators. On the one hand, the lack of n-3 polyunsaturated fatty acids (PUFAs) in the body leads to impaired molecular mechanisms of glucose transport, the formation of unresolved inflammation. On the other hand, excessive formation of free fatty acids (FFAs) underlies the development of oxidative stress and mitochondrial dysfunction in MetS. Understanding the molecular mechanisms of the participation of FAs and their metabolites in the pathogenesis of MetS will contribute to the development of new diagnostic methods and targeted therapy for this disease. The purpose of this review is to highlight recent advances in the study of the effect of fatty acids as modulators of insulin response and inflammatory process in the pathogenesis and treatment for MetS.

Lifestyle and Food Habits Impact on Chronic Diseases: Roles of PPARs

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that exert important functions in mediating the pleiotropic effects of diverse exogenous factors such as physical exercise and food components. Particularly, PPARs act as transcription factors that control the expression of genes implicated in lipid and glucose metabolism, and cellular proliferation and differentiation. In this review, we aim to summarize the recent advancements reported on the effects of lifestyle and food habits on PPAR transcriptional activity in chronic disease.

The Differences in the Proteome Profile of Cannabidiol-Treated Skin Fibroblasts following UVA or UVB Irradiation in 2D and 3D Cell Cultures

Cannabidiol (CBD), as the only phytocannabinoid that has no psychoactive effect, has both antioxidant and anti-inflammatory effects, and thus might be suggested as a cytoprotective compound against UV-induced metabolic changes in skin cells. Therefore, the aim of this study was to investigate the level of protective CBD activity by evaluating the proteomic profile of 2D and 3D cultured skin fibroblasts models following exposure to UVA and UVB radiation. The CBD cytoprotective effect against UV-induced damage in 2D and 3D cultured fibroblasts were different. The main alterations focus on the range of cell reaction and involved different proteins associated with various molecular functions. In the 2D cultured cells, following UV radiation, the major changes were associated with proteins involved in antioxidant response and inflammation, while, in the 3D cultured fibroblasts, CBD action against UV induced changes were mainly associated with the activation of signalling pathways. Therefore, the knowledge of the CBD action in a multilayer skin cells model allowed for the prediction of changes in cell-cell interactions and skin cell metabolism. Knowledge about the lower protective effect of CBD in 3D cultured fibroblasts should be taken into account during the design of UV light protection.

Novel Hybrid Gels Made of High and Low Molecular Weight Hyaluronic Acid Induce Proliferation and Reduce Inflammation in an Osteoarthritis In Vitro Model Based on Human Synoviocytes and Chondrocytes

High molecular weight hyaluronan (H-HA) has a pivotal role in the maintenance of normal functions of synovial fluid and structure of the articular joint, but it has been shown that its concentration is reduced in patients affected by degenerative cartilage diseases, such as osteoarthritis (OA). The aim of this study was to investigate the anti-inflammatory effects and properties of hybrid cooperative complexes based on high and low molecular weight hyaluronan (HCC) compared to H-HA on human primary cells derived by pathological joints. In addition, the rheological behavior of HCC was evaluated in order to define their potential as viscosupplement gel in degenerated joints. The experiments were performed using an in vitro model of OA based on human chondrocytes and synoviocytes isolated from degenerated joints of patients hospitalized for surgical replacement. In order to assess the anti-inflammatory effects of HCC, we evaluated NF-kB, COMP-2, IL-6, and IL-8 as specific markers at the transcriptional and/or protein level. Moreover, the proliferative properties of HCC were assessed using time lapse video microscopy. We showed that chondrocytes and synoviocytes clearly presented an altered cytokine profile compatible with a severe ongoing inflammation status. H-HA and, above all, HCC significantly reduced levels of the specific biomarkers evaluated and improved cartilage healing. The rheological profile indicated HCC suitability for intra-articular injection in joint diseases. HCC viscoelastic properties and the protective/anti-inflammatory effect on human chondrocytes and synoviocytes suggest the novel HCC-based gels as a valid support for OA management.

Role of cannabinoid receptor 1 and the peroxisome proliferator-activated receptor α in mediating anti-nociceptive effects of synthetic cannabinoids and a cannabinoid-like compound

Osteoarthritis (OA) is characterized by cartilage degeneration, subchondral sclerosis, and pain. Cannabinoids have well-established anti-nociceptive properties in animal models of chronic pain. The aim of this study is to evaluate the anti-nociceptive effects of synthetic cannabinoids (WIN-55,212 and HU210) and the cannabinoid-like compound palmitoylethanolamide (PEA) in rat models of OA and to assess the role of cannabinoid receptor 1 (CB1) and the peroxisome proliferator-activated receptor α (PPARα) in mediating these effects. Intra-articular injection of monosodium iodoacetate (MIA) in the knee joint was used as a model of osteoarthritis. The von Frey filament test and weight-bearing difference were used to assess the anti-nociceptive effects of WIN-55,212, HU210, and PEA on MIA-induced OA in rats. Open-field locomotor activity system was used confirm the analgesic effects of those compounds. HU210, WIN55, 212, and PEA in a dose-dependent manner restored the paw withdrawal threshold (PWT) and the weight-bearing difference induced by MIA injection. SR141716A (a CB1 antagonist) significantly reversed the anti-nociceptive effects of all the administered drugs in terms of PWT. However, in terms of weight-bearing difference, SR141716A significantly reduced the anti-nociceptive effect of HU210 but not PEA or WIN55, 212. GW6471 (a PPARα antagonist) significantly reversed the anti-nociceptive effects of PEA but not those of HU210 or WIN55, 212. HU210, WIN55, 212 and PEA significantly restored the MIA-induced reduction in locomotor activity. In conclusions, both CB1 and PPARα receptors are involved in mediating pain in osteoarthritis. Therefore, targeting these receptors may be of great clinical value.

Self-regulation of the inflammatory response by peroxisome proliferator-activated receptors

The peroxisome proliferator-activated receptor (PPAR) family includes three transcription factors: PPARα, PPARβ/δ, and PPARγ. PPAR are nuclear receptors activated by oxidised and nitrated fatty acid derivatives as well as by cyclopentenone prostaglandins (PGA₂ and 15d-PGJ₂) during the inflammatory response. This results in the modulation of the pro-inflammatory response, preventing it from being excessively activated. Other activators of these receptors are nonsteroidal anti-inflammatory drug (NSAID) and fatty acids, especially polyunsaturated fatty acid (PUFA) (arachidonic acid, ALA, EPA, and DHA). The main function of PPAR during the inflammatory reaction is to promote the inactivation of NF-κB. Possible mechanisms of inactivation include direct binding and thus inactivation of p65 NF-κB or ubiquitination leading to proteolytic degradation of p65 NF-κB. PPAR also exert indirect effects on NF-κB. They promote the expression of antioxidant enzymes, such as catalase, superoxide dismutase, or heme oxygenase-1, resulting in a reduction in the concentration of reactive oxygen species (ROS), i.e., secondary transmitters in inflammatory reactions. PPAR also cause an increase in the expression of IκBα, SIRT1, and PTEN, which interferes with the activation and function of NF-κB in inflammatory reactions.

Chondroprotection of PPARα activation by WY14643 via autophagy involving Akt and ERK in LPS-treated mouse chondrocytes and osteoarthritis model

Autophagy maintains cellular homoeostasis. The enhancement of autophagy in chondrocytes could prevent osteoarthritis (OA) progression in articular cartilage. Peroxisome proliferator-activated receptor α (PPARα) activation may also protect articular chondrocytes against cartilage degradation in OA. However, whether the protective effect of activated PPARα is associated with autophagy induction in chondrocytes is not determined. In this study, we investigated the effect of PPARα activation by its agonist, WY14643, on the protein expression level of Aggrecan and ADAMTS5, and the protein expression level of autophagy biomarkers, including LC3B and P62, using Western blotting analysis in isolated mouse chondrocytes pre-treated with lipopolysaccharides (LPS, mimicking OA chondrocytes) with or without the autophagy inhibitor chloroquine diphosphate salt. Furthermore, Akt and ERK phosphorylation was detected in LPS-treated chondrocytes in response to WY14643. In addition, the effect of intra-articularly injected WY14643 on articular cartilage in a mouse OA model established by the destabilization of the medial meniscus was assessed using the Osteoarthritis Research Society International (OARSI) histopathology assessment system, along with the detection of Aggrecan, ADAMTS5, LC3B and P62 protein levels using immunohistochemistry assay. The results indicated that PPARα activation by WY14643 promoted proteoglycan synthesis by autophagy enhancement in OA chondrocytes in vivo and in vitro concomitant with the elevation of Akt and ERK phosphorylation. Therefore, autophagy could contribute to the chondroprotection of PPARα activation by WY14643, with the implication that PPARα activation by WY14643 may be a potential approach for OA therapy.