Activation Of Peroxisome Proliferator-activated Receptor-γ Research Articles

Sinapic acid modulates oxidative stress and metabolic disturbances to attenuate ovarian fibrosis in letrozole-induced polycystic ovary syndrome SD rats.

Sinapic acid (SA) is renowned for its many pharmacological activities as a polyphenolic compound. The cause of polycystic ovary syndrome (PCOS), a commonly encountered array of metabolic and hormonal abnormalities in females, has yet to be determined. The present experiment was performed to evaluate the antifibrotic properties of SA in rats with letrozole-induced PCOS-related ovarian fibrosis. SA treatment successfully mitigated the changes induced by letrozole in body weight (BW) (p < .01) and relative ovary weight (p < .05). Histological observation revealed that SA reduced the number of atretic and cystic follicles (AFs) and (CFs) (p < .01), as well as ovarian fibrosis, in PCOS rats. Additionally, SA treatment impacted the serum levels of sex hormones in PCOS rats. Luteinizing hormone (LH) and testosterone (T) levels were decreased (p < .01, p < .05), and follicle-stimulating hormone (FSH) levels were increased (p < .05). SA administration also decreased triglyceride (TG) (p < .01) and total cholesterol (TC) levels (p < .05) and increased high-density lipoprotein cholesterol (HDL-C) levels (p < .01), thereby alleviating letrozole-induced metabolic dysfunction in PCOS rats. Furthermore, SA treatment targeted insulin resistance (IR) and increased the messenger RNA (mRNA) levels of antioxidant enzymes in the ovaries of PCOS rats. Finally, SA treatment enhanced the activity of peroxisome proliferator-activated receptor-γ (PPAR-γ), reduced the activation of transforming growth factor-β1 (TGF-β1)/Smads, and decreased collagen I, α-smooth muscle actin (α-SMA), and connective tissue growth factor (CTGF) levels in the ovaries of PCOS rats. These observations suggest that SA significantly ameliorates metabolic dysfunction and oxidative stress and ultimately reduces ovarian fibrosis in rats with letrozole-induced PCOS.

Serelaxin inhibits LPS-induced inflammatory response in cardiac fibroblasts by activating PPAR-γ and suppressing NF-κB signaling pathway.

Serelaxin has an inhibitory effect on fibrosis. However, whether the anti-fibrotic effects of serelaxin are achieved by inhibiting the inflammatory response has not been clarified. This study aimed to investigate the role of serelaxin in lipopolysaccharide (LPS)-induced inflammation in cardiac fibroblasts (CFs) and elucidate the underlying mechanisms.CFs were isolated from adult rat hearts. The effect of serelaxin on the inhibition of the inflammatory response after LPS induction was examined. Cell viability was measured by MMT assay. Cell proliferation was determined using the cell-counting kit-8. The levels of inflammatory cytokines IL-1β, IL-6, TNF-α, and IL-10 were measured using an enzyme-linked immunosorbent assay (ELISA). The mRNA levels of α-SMA, collagen I/III, MMP-2, MMP-9, IL-1β, IL-6,TNF-α, IL-10, IκBα, p-IκBα, p65 subunit of nuclear factor-kappa B (NF-κB) and peroxisome proliferator-activated receptor-γ (PPAR-γ) were assessed by real-time quantitative PCR (RT-qPCR). The protein levels of α-SMA, collagen I/III, MMP-2, MMP-9, IκBα, p-IκBα, p65, p-p65 and PPAR-γ were examined by western blotting.Serelaxin inhibited LPS-induced IL-1β, IL-6, TNF-α, α-SMA, and collagen I/III, and elevated the expression of IL-10, MMP-2 and MMP-9. Moreover, LPS-induced activation of NF-κB pathway was suppressed by serelaxin treatment. Further studies showed that serelaxin did not significantly increase the expression of PPAR-γ mRNA and protein, but activated PPAR-γ activity, and the PPAR-γ inhibitor GW9662 reversed the inhibitory effect of serelaxin on IL-1β, IL-6, and TNF-α production. These results suggest that serelaxin alleviates cardiac fibrosis by stimulating PPAR-γ via a ligand-independent mechanism which subsequently abolish the expression of NF-κB signalling pathway.

Tumor necrosis factor-α reduces adiponectin production by decreasing transcriptional activity of peroxisome proliferator-activated receptor-γ in calf adipocytes

Adiponectin (encoded by ADIPOQ) is an adipokine that orchestrates energy homeostasis by modulating glucose and fatty acid metabolism in peripheral tissues. During the periparturient period, dairy cows often develop adipose tissue inflammation and decreased plasma adiponectin levels. Proinflammatory cytokine tumor necrosis factor-α (TNF-α) plays a pivotal role in regulating the endocrine functions of adipocytes, but whether it affects adiponectin production in calf adipocytes remains obscure. Thus, the present study aimed to determine whether TNF-α could affect adiponectin production in calf adipocytes and to identify the underlying mechanism. Adipocytes isolated from Holstein calves were differentiated and used for (1) BODIPY493/503 staining; (2) treatment with 0.1 ng/mL TNF-α for different times (0, 8, 16, 24, or 48 h); (3) transfection with peroxisome proliferator-activated receptor-γ (PPARG) small interfering RNA for 48 h followed by treatment with or without 0.1 ng/mL TNF-α for 24 h; and (4) overexpression of PPARG for 48 h followed by treatment with or without 0.1 ng/mL TNF-α for 24 h. After differentiation, obvious lipid droplets and secretion of adiponectin were observed in adipocytes. Treatment with TNF-α did not alter mRNA abundance of ADIPOQ but reduced the total and high molecular weight (HMW) adiponectin content in the supernatant of adipocytes. Quantification of mRNA abundance of endoplasmic reticulum (ER)/Golgi resident chaperones involved in adiponectin assembly revealed that ER protein 44 (ERP44), ER oxidoreductase 1α (ERO1A), and disulfide bond-forming oxidoreductase A-like protein (GSTK1) were downregulated in TNF-α-treated adipocytes, while 78-kDa glucose-regulated protein and Golgi-localizing γ-adaptin ear homology domain ARF binding protein-1 were unaltered. Moreover, TNF-α diminished nuclear translocation of PPARγ and downregulated mRNA abundance of PPARG and its downstream target gene fatty acid synthase, suggesting that TNF-α suppressed the transcriptional activity of PPARγ. In the absence of TNF-α, overexpression of PPARG enhanced the total and HMW adiponectin content in supernatant and upregulated the mRNA abundance of ADIPOQ, ERP44, ERO1A, and GSTK1 in adipocytes. However, knockdown of PPARG reduced the total and HMW adiponectin content in supernatant and downregulated the mRNA abundance of ADIPOQ, ERP44, ERO1A, and GSTK1 in adipocytes. In the presence of TNF-α, overexpression of PPARG decreased, while knockdown of PPARG further exacerbated TNF-α-induced reductions in total and HMW adiponectin secretion and gene expression of ERP44, ERO1A, and GSTK1. Overall, TNF-α reduces adiponectin assembly in the calf adipocyte, which may be partly mediated by attenuation of PPARγ transcriptional activity. Thus, locally elevated levels of TNF-α in adipose tissue may be one reason for the decrease in circulating adiponectin in periparturient dairy cows.

The impact of peroxisome proliferator-activated receptor-γ activating angiotensin receptor blocker on outcomes of patients receiving immunotherapy.

Certain angiotensin receptor blockers (ARBs) have peroxisome proliferator-activated receptor-γ (PPAR-γ) activation property, which has been associated with improved programmed cell death ligand 1 blockade and cytotoxic T lymphocyte-mediated antitumor activity. We conducted a retrospective cohort study to investigate the impact of PPAR-γ-activating ARBs on patient survival in patients treated with immune checkpoint inhibitors (ICIs) across all types of cancers. A total of 167 patients receiving both angiotensin receptor blockers (ARBs) and immune checkpoint inhibitors (ICIs) were included. Compared with non-PPAR-γ-ARB users (n= 102), PPAR-γ-ARB users (n= 65) had a longer median overall survival (not reached [IQR, 16.0-not reached] vs. 18.6 [IQR, 6.1-38.6] months) and progression-free survival (17.3 [IQR, 5.1-not reached] vs. 8.2 [IQR, 2.4-18.6] months). In Cox regression analysis, the use of PPAR-γ-activating ARBs had an approximately 50% reduction in all-cause mortality and disease progression. Patients who received PPAR-γ-activating ARBs also had higher clinical benefit rates than non-PPAR-γ-ARB users (82% vs. 61%, p= 0.005). The use of ARBs with PPAR-γ-activating property is linked with better survival among patients receiving ICIs.

Discovery of Novel Thiazolidinedione-Derivatives with Multi-Modal Antidiabetic Activities In Vitro and In Silico.

Diabetes mellitus (DM) and related complications continue to exert a significant burden on health care systems globally. Although conventional pharmacological therapies are beneficial in the management of this metabolic condition, it is still necessary to seek novel potential molecules for its management. On this basis, we have synthesised and evaluated the anti-diabetic properties of four novel thiazolidinedione (TZD)-derivatives. The TZD derivatives were synthesised through the pharmacophore hybridisation strategy based on N-arylpyrrole and TZD. The resultant derivatives at different concentrations were screened against key enzymes of glucose metabolism and glucose utilisation in the liver (HEP-G2) cell line. Additionally, peroxisome proliferator-activated receptor-γ activation was performed through docking studies. Docking of these molecules against PPAR-γ predicted strong binding, similar to that of rosiglitazone. Hence, TZDD2 was able to increase glucose uptake in the liver cells as compared to the control. The enzymatic inhibition assays showed a relative inhibition activity; with all four derivatives exhibiting ≥ 50% inhibition activity in the α-amylase inhibition assay and a concentration dependent activity in the α-glucosidase inhibition assay. All four derivatives exhibited ≥30% inhibition in the aldose reductase inhibition assay, except TZDD1 at 10 µg/mL. Interestingly, TZDD3 showed a decreasing inhibition activity. In the dipeptidyl peptidase-4 inhibition assay, TZDD2 and TZDD4 exhibited ≥20% inhibition activity.

PPARγ activation improved learning and memory and attenuated oxidative stress in the hippocampus and cortex of aged rats.

Oxidative stress has an important role in brain aging and its consequences include cognitive decline and physiological disorders. Peroxisome proliferator-activated receptor-γ (PPARγ) activation has been suggested to decrease oxidative stress. In the current research, the effect of PPARγ activation by pioglitazone(Pio) on learning, memory and oxidative stress was evaluated in aged rats. The rats were divided into five groups. In the Control group, vehicle (saline-diluted dimethyl sulfoxide (DMSO)) and saline were injected instead of Pio and scopolamine (Sco), respectively. In the Sco group, the vehicle was injected instead of Pio and the rats were injected by Sco 30 min before the behavioral tests. In the Sco-Pio 10, Sco-Pio 20, and Sco-Pio 30 groups, 10, 20, and 30 mg/kg Pio was injected and finally, the rats were injected with Sco 30 min before the behavioral tests. Morris water mater maze(MWM) and passive avoidance(PA) tests were carried out, and finally, the hippocampus and cortex were removed for biochemical assessments. The results showed that the highest dose of Pio decreased the traveling time and distance during 5 days of learning and increased the time and distance in the target area on the probe day of MWM. The highest dose of Pio also prolonged the delay time for entering the dark and total time spent in the light while decreasing the total time spent in and the number of entries into the dark in PA test. Pio especially, in the medium and highest doses, decreased MDA while increasing thiol, superoxide dismutase, and catalase in the hippocampus and cortex. It is concluded that PPARγ activation by Pio as an agonist improved learning and memory in aged rats probably by attenuating oxidative stress in the hippocampus and cortex.

Activation of PPARγ Protects Obese Mice from Acute Lung Injury by Inhibiting Endoplasmic Reticulum Stress and Promoting Mitochondrial Biogenesis.

Objective Obesity-induced endoplasmic reticulum (ER) stress plays a role in increased susceptibility to acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). The activation of peroxisome proliferator-activated receptor-γ (PPARγ) is associated with lung protection and is effective in ameliorating ER stress and mitochondrial dysfunction. The aim of this study was to investigate the expression of PPARγ in the lung tissues of obese mice and explore whether the PPARγ-dependent pathway could mediate decreased ALI/ARDS by regulating ER stress and mitochondrial biogenesis. Methods We determined PPARγ expression in the lung tissues of normal and obese mice. ALI models of alveolar epithelial cells and of obese mice were used and treated with either PPARγ activator rosiglitazone (RSG) or PPARγ inhibitor GW9662. Lung tissue and cell samples were collected to assess lung inflammation and apoptosis, and ER stress and mitochondrial biogenesis were detected. Results PPARγ expression was significantly decreased in the lung tissue of obese mice compared with that in normal mice. Both in vivo and in vitro studies have shown that activation of PPARγ leads to reduced expression of the ER stress marker proteins 78-kDa glucose-regulated protein (GRP78), C/EBP homologous protein (CHOP), and Caspase12. Conversely, expression of the mitochondrial biogenesis-related proteins peroxisome proliferator-activated receptor γ coactivator 1 (PGC-1α), nuclear respiratory factor-1 (NRF-1), and mitochondrial transcription factor A (TFAM) increased. Furthermore, activation of PPARγ is associated with decreased levels of lung inflammation and epithelial apoptosis and increased expression of adiponectin (APN) and mitofusin2 (MFN2). GW9662 bound to PPARγ and blocked its transcriptional activity and then diminished the protective effect of PPARγ on lung tissues. Conclusions PPARγ activation exerts anti-inflammation effects in alveolar epithelia by alleviating ER stress and promoting mitochondrial biogenesis. Therefore, lower levels of PPARγ in the lung tissues of obese mice may lead to an increased susceptibility to ALI.

Maresin 1 enhances osteogenic potential of mesenchymal stem cells by modulating macrophage peroxisome proliferator-activated receptor-γ-mediated inflammation resolution

Inflammation resolution plays a significant role in attenuating bone injury aggravated by acute inflammation and maintaining bone homeostasis. Maresin 1 (MaR1), a specialized pro-resolving mediators (SPMs), is biosynthesised in macrophages (Mφs) that regulates acute inflammation. Strategies to accelerate the resolution of inflammation in bone repair include not only promoting vanish of acute inflammation, also improving osteogenic microenvironment. Here, previously prepared difunctional demineralized bone matrix (DBM) scaffold was used to study thoroughly the “cross-talk” between Mφs lipid metabolism and mesenchymal stem cells (MSCs) behaviors in vitro. The pro-resolving mechanism in Mφs treated with MaR1 was elaborated. Furthermore, the biological behaviors of MSCs in co-culture system were evaluated. The results indicated that MaR1 had an enhanced capability and performance in peroxisome proliferator-activated receptor-γ (PPAR-γ) activation, M2-type Mφs polarization, and lipid droplets (LDs) biogenesis in Mφs in vitro. The nuclear receptor PPAR-γ enhanced the anti-inflammatory proteins expression and the polarization of Mφs toward M2 subtype, thereby favoring the proliferation, migration, and osteogenesis of MSCs. Overall, the results verified that MaR1 facilitated MSCs behaviors by regulating PPAR-γ-mediated inflammatory response, which implied that PPAR-γ exhibited a significant role in the dialogue between MSCs behaviors and Mφs lipid metabolism.

Pioglitazone, a Peroxisome Proliferator-Activated Receptor-γ Agonist, Downregulates the Inflammatory Response in Cutaneous Leishmaniasis Patients Without Interfering in Leishmania braziliensis Killing by Monocytes.

Patients with cutaneous leishmaniasis (CL) due to Leishmania braziliensis infection have an exacerbated inflammatory response associated with tissue damage and ulcer development. An increase in the rate of patients who fail therapy with pentavalent antimony has been documented. An adjuvant therapy with an anti-inflammatory drug with the potential of Leishmania killing would benefit CL patients. The aim of the present study was to investigate the contribution of peroxisome proliferator-activated receptor-γ (PPAR-γ) activation by pioglitazone in the regulation of the inflammatory response and L. braziliensis killing by monocytes. Pioglitazone is an oral drug used in the treatment of diabetes, and its main mechanism of action is through the activation of PPAR-γ, which is expressed in many cell types of the immune response. We found that activation of PPAR-γ by pioglitazone decreases the inflammatory response in CL patients without affecting L. braziliensis killing by monocytes. Our data suggest that pioglitazone may serve as an adjunctive treatment for CL caused by L. braziliensis.

Beta-Sitosterol Modulates the Migration of Vascular Smooth Muscle Cells via the PPARG/AMPK/mTOR Pathway

Introduction: The increased migration of vascular smooth muscle cells (VSMCs) is an essential pathological factor in the early development of atherosclerosis. Beta-sitosterol (BS), a natural phytosterol abundant in plant seeds, exhibits various bioactivities, including cardioprotective effects. However, its effects on VSMC migration and underlying mechanisms remain to be explored. Method and Result: BS inhibited the proliferation and migration of angiotensin II-induced A7r5 cells and reduced intracellular oxidative stress. Targets related to VSMC migration and the targets of BS were screened, cross-referenced, and analyzed by network pharmacology combined with molecular docking technology. The identified targets were verified at the protein and gene levels using Western blotting and quantitative PCR, respectively. BS was observed to activate peroxisome proliferator-activated receptor-γ (PPARG) and adenosine 5′-monophosphate-activated protein kinase (AMPK) and negatively regulate mammalian target of rapamycin (mTOR) expression. Furthermore, a PPARG inhibitor reversed the BS-induced activation of AMPK and mTOR. Conclusion: This study indicated that regulation of the PPARG/AMPK/mTOR signaling pathway could potentially contribute to the inhibitory effects of BS on angiotensin II-induced VSMC migration.

Single-Cell Proteomics and Tumor RNAseq Identify Novel Pathways Associated With Clofazimine Sensitivity in PI- and IMiD- Resistant Myeloma, and Putative Stem-Like Cells.

Multiple myeloma (MM) is an incurable plasma cell malignancy with dose-limiting toxicities and inter-individual variation in response/resistance to the standard-of-care/primary drugs, proteasome inhibitors (PIs), and immunomodulatory derivatives (IMiDs). Although newer therapeutic options are potentially highly efficacious, their costs outweigh the effectiveness. Previously, we have established that clofazimine (CLF) activates peroxisome proliferator-activated receptor-γ, synergizes with primary therapies, and targets cancer stem-like cells (CSCs) in drug-resistant chronic myeloid leukemia (CML) patients. In this study, we used a panel of human myeloma cell lines as in vitro model systems representing drug-sensitive, innate/refractory, and clonally-derived acquired/relapsed PI- and cereblon (CRBN)-negative IMiD-resistant myeloma and bone marrow-derived CD138+ primary myeloma cells obtained from patients as ex vivo models to demonstrate that CLF shows significant cytotoxicity against drug-resistant myeloma as single-agent and in combination with PIs and IMiDs. Next, using genome-wide transcriptome analysis (RNA-sequencing), single-cell proteomics (CyTOF; Cytometry by time-of-flight), and ingenuity pathway analysis (IPA), we identified novel pathways associated with CLF efficacy, including induction of ER stress, autophagy, mitochondrial dysfunction, oxidative phosphorylation, enhancement of downstream cascade of p65-NFkB-IRF4-Myc downregulation, and ROS-dependent apoptotic cell death in myeloma. Further, we also showed that CLF is effective in killing rare refractory subclones like side populations that have been referred to as myeloma stem-like cells. Since CLF is an FDA-approved drug and also on WHO’s list of safe and effective essential medicines, it has strong potential to be rapidly re-purposed as a safe and cost-effective anti-myeloma drug.

Procyanidin B2 Attenuates Nicotine-Induced Hepatocyte Pyroptosis through a PPARγ-Dependent Mechanism.

Procyanidin B2 (PCB2), a natural flavonoid, has been demonstrated to exert anti-oxidation and anti-inflammatory effects on hepatic diseases. Increasing evidence shows the hepatoxicity of nicotine. However, whether PCB2 protects against nicotine-induced hepatoxicity and the underlying mechanisms remains uncharacterized. Here, we reported that nicotine promoted hepatocyte pyroptosis, as evidenced by the elevation of propidium iodide (PI)-positive cells, the activation of Caspase-1 and gasdermin D (GSDMD), the enhanced expression of NOD-like receptor containing pyrin domain 3 (NLRP3) and the increased release of lactate dehydrogenase (LDH), interleukin (IL)-1β and IL-18. The silencing of GSDMD by small interfering RNA (siRNA) efficiently inhibited the release of LDH and the secretion of IL-1β and IL-18. In addition, rosiglitazone (RGZ) prevented hepatocyte pyroptosis induced by nicotine. Furthermore, we showed that PCB2 attenuated nicotine-induced pyroptosis through the activation of peroxisome proliferator-activated receptor-γ (PPARγ) in hepatocytes. Moreover, administration of PCB2 ameliorated liver injury and hepatocyte pyroptosis in nicotine-treated mice. Hence, our findings demonstrated that PCB2 attenuated pyroptosis and liver damage in a PPARγ-dependent manner. Our results suggest a new mechanism by which PCB2 exerts its liver protective effects.

Molecular mechanisms of aberrant neutrophil differentiation in glycogen storage disease type Ib.

Glycogen storage disease type Ib (GSD-Ib), characterized by impaired glucose homeostasis, neutropenia, and neutrophil dysfunction, is caused by a deficiency in glucose-6-phosphate transporter (G6PT). Neutropenia in GSD-Ib has been known to result from enhanced apoptosis of neutrophils. However, it has also been raised that neutrophil maturation arrest in the bone marrow would contribute to neutropenia. We now show that G6pt-/- mice exhibit severe neutropenia and impaired neutrophil differentiation in the bone marrow. To investigate the role of G6PT in myeloid progenitor cells, the G6PT gene was mutated using CRISPR/Cas9 system, and single cell-derived G6PT-/- human promyelocyte HL-60 cell lines were established. The G6PT-/- HL-60s exhibited impaired neutrophil differentiation, which is associated with two mechanisms: (i) abnormal lipid metabolism causing a delayed metabolic reprogramming and (ii) reduced nuclear transcriptional activity of peroxisome proliferator-activated receptor-γ (PPARγ) in G6PT-/- HL-60s. In this study, we demonstrated that G6PT is essential for neutrophil differentiation of myeloid progenitor cells and regulates PPARγ activity.

Obesity alters pathology and treatment response in inflammatory disease.

Decades of work have elucidated cytokine signalling and transcriptional pathways that control T cell differentiation and haveled the way to targeted biologic therapies that are effective in a range of autoimmune, allergic and inflammatory diseases. Recent evidence indicates that obesity and metabolic disease can also influence the immune system1-7, although the mechanisms and effects on immunotherapy outcomes remain largely unknown. Here, using two models of atopic dermatitis, we show that lean and obese mice mount markedly different immune responses. Obesity converted the classical type 2 T helper (TH2)-predominant disease associated with atopic dermatitis to a more severe disease with prominent TH17 inflammation.We also observed divergent responses to biologic therapies targeting TH2 cytokines, which robustly protected lean mice but exacerbated disease in obese mice. Single-cell RNA sequencing coupled with genome-wide binding analyses revealed decreased activity of nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ) in TH2 cells from obese mice relative to lean mice. Conditional ablation of PPARγ in T cells revealed that PPARγ is required to focus the in vivo TH response towards a TH2-predominant state and prevent aberrant non-TH2 inflammation. Treatment of obese mice with a small-molecule PPARγ agonist limited development of TH17 pathology and unlocked therapeutic responsiveness to targeted anti-TH2 biologic therapies. These studies reveal the effects of obesity on immunological disease and suggest a precision medicine approach to target the immune dysregulation caused by obesity.

Metformin alleviates LTA-induced inflammatory response through PPARγ/MAPK/NF-κB signaling pathway in bovine mammary epithelial cells

Mastitis is a common inflammatory cow mammary infection; that causes significant economic loss in dairy industry. Given the interesting connection between metformin’s anti-inflammatory function and mastitis model induced by LTA in pbMECs, our objective was to prove that metformin was beneficial in suppressing proinflammatory response induced by LTA through modulation of mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) signaling pathways and activation of peroxisome proliferator-activated receptor-γ (PPARγ) in pbMECs. The proliferation of cells and mRNA expression were measured using EdU assay and quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Immunoblotting and immunofluorescence analysis were conducted to evaluate the expression of target proteins in inflammatory and anti-inflammatory responses to metformin and LTA. Finally, pbMECs were allowed to treat with the PPAR antagonist GW9662, and inflammatory markers were detected in the cells. Our results showed that LTA concentration at 100 µg/mL significantly stimulated the MAPK14, IL-6 and IL-1β mRNA expressions compared to the control cells (P < 0.05) in dose-dependent tests for LTA. Metformin suppressed the phosphorylation expressions of MAPK (ERK1/2, p38, and JNK) in LTA-stimulated pbMECs. Metformin also reduced the protein expression of NF-κB, interleukin-8 (IL-8), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in pbMECs pretreated with LTA. Metformin administration activated PPARγ phosphorylation by up-regulating the expression of PPARγ in LTA-stimulated pbMECs. Treatment with GW9662 resulted in increased IL-6 expression, which was reversed by metformin. These findings collectively indicated that metformin act to attenuate LTA-stimulated inflammatory response in pbMECs by suppressing MAPK and NF-κB activation via a mechanism partially dependent on PPARγ activation. These results suggested that metformin could function as an anti-inflammatory drug

Lycium barbarum polysaccharides alleviate LPS-induced inflammatory responses through PPARγ/MAPK/NF-κB pathway in bovine mammary epithelial cells.

Current research examined Lycium barbarum polysaccharides (LBP) for combating LPS-induced inflammatory responses in primary bovine mammary epithelial cells. We uncovered a preventive role of LBP in reducing detrimental effects induced by LPS including inhibition of NF-κB and MAPK along with peroxisome proliferator-activated receptor-γ (PPARγ) activation. The decrease in cell proliferation due to LPS was curtailed by pretreatment with LBP. Moreover, the effect of LBP on regulation of inflammatory responses in bovine mammary epithelial cell was PPARγ dependent. Collectively, data suggest that LBP reverses LPS-induced inflammatory response via MAPK/NF-κB signaling in a PPARγ-activation-dependent manner. Thus, the study provides new insights into therapeutic strategies for combating mastitis using LBP and highlighted the link between PPARγ and regulation of mammary cell inflammation.

Metabolism of natural forms of vitamin E and biological actions of vitamin E metabolites

Natural forms of vitamin E comprise four tocopherols and four tocotrienols. During the last twenty years, there have been breakthroughs in our understanding of vitamin E metabolism and biological activities of vitamin E metabolites. Research has established that tocopherols and tocotrienols are metabolized via ω-hydroxylase (CYP4F2)-initiated side chain oxidation to form 13′-hydroxychromanol and 13′-carobyxychromanol (13′-COOH). 13′-COOHs are further metabolized via β-oxidation and sulfation to intermediate carboxychromanols, terminal metabolite carboxyethyl-hydroxychroman (CEHC), and sulfated analogs. Animal and human studies show that γ-, δ-tocopherol and tocotrienols are more extensively metabolized than α-tocopherol (αT), as indicated by higher formation of CEHCs and 13′-COOHs from non-αT forms than those from αT. 13′-COOHs are shown to be inhibitors of cyclooxygenase-1/-2 and 5-lipoxygenase and much stronger than CEHCs for these activities. 13′-COOHs inhibit cancer cell growth, modulate cellular lipids and activate peroxisome proliferator-activated receptor-γ and pregnane X receptor. Consistent with mechanistic findings, αT-13′-COOH or δTE-13′-COOH, respective metabolites of αT or δ-tocotrienol, show anti-inflammatory and cancer-preventive effects, modulates the gut microbiota and prevents β-amyloid formation in mice. Therefore, 13′-COOHs are a new class of bioactive compounds with anti-inflammatory and anti-cancer activities and potentially capable of modulating lipid and drug metabolism. Based on the existing evidence, this author proposes that metabolites may contribute to disease-preventing effects of γ-, δ-tocopherol and tocotrienols. The role of metabolites in αT's actions may be somewhat limited considering controlled metabolism of αT because of its association with tocopherol-transport protein and less catabolism by CYP4F2 than other vitamin E forms.

Retraction.

The Anatomical RecordVolume 304, Issue 12 p. 2904-2904 RetractionFree Access Retraction This article retracts the following: RETRACTED: Alpinumisoflavone suppresses human Glioblastoma cell growth and induces cell cycle arrest through activating peroxisome proliferator-activated receptor-γ Lijuan He, Dong Shen, Jianmei Li, Weidong Mao, Volume 303Issue 11The Anatomical Record pages: 2801-2810 First Published online: January 8, 2020 First published: 27 October 2021 https://doi.org/10.1002/ar.24816AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Alpinumisoflavone suppresses human glioblastoma cell growth and induces cell cycle arrest through activating peroxisome proliferator-activated receptor-γ”, by Lijuan HE, Dong SHEN, Jianmei LI, and Weidong MAO. The above article, published in The Anatomical Record (DOI: 10.1002/ar.24350) is retracted by agreement among the authors and the Editor-in-Chief, Dr. Kurt H. Albertine, with notification to the American Association for Anatomy and Wiley Periodicals LLC. The decision is the result of an investigation that revealed issues of scientific integrity in the data that compromise the findings of the paper. REFERENCE He, L., Shen, D., Li, J., & Mao, W. (2020 Nov). Alpinumisoflavone suppresses human Glioblastoma cell growth and induces cell cycle arrest through activating peroxisome proliferator-activated receptor-γ. Anat Rec (Hoboken)., 303(11), 2801– 2810. https://doi.org/10.1002/ar.24350Wiley Online LibraryCASPubMedGoogle Scholar Volume304, Issue12December 2021Pages 2904-2904 ReferencesRelatedInformation

Exercise Mimetics: Fact Or Fantasy?

The abundant health benefits of physical exercise are not being translated into practice. In an effort to short circuit the need for physical activity to promote health, exercise-mimetic agents are being developed; they mimic the action of peptide molecules released from exercised muscles. The intention is to mimic biochemi-cal responses even without performing exercise. Technologies have advanced to identify various exercise-induced proteins, called myokines, and to develop ligands which bind to the myokine receptors. A number of such chemicals exist that mimic the effects of activating Peroxisome proliferator-activated receptor-γ (PPARγ) coactivator 1α (PGC-1 α), Peroxisome proliferator-activated receptor β/δ (PPAR β/δ) and AMP-activated protein kinase (AMPK). Most such agents were test-ed in animal models with varying degrees of success and mostly undesirable ad-verse effects. The increasing complexity of exercise response is being recognized, making the development and use of single ‘exercise-mimetics’ ineffective, except for some narrow indications. In addition, some of the performance enhancing ex-ercise-mimetics are being misused by endurance athletes, with the chemicals be-ing banned as doping agents. In a fascinating interaction between physiology and pharmacology, agents that can mimic the beneficial effects of physical exercise are an enticing possibility over the distant horizon.

Pioglitazone Attenuates Lupus Nephritis Symptoms in Mice by Modulating miR-21-5p/TIMP3 Axis: the Key Role of the Activation of Peroxisome Proliferator-Activated Receptor-γ.

Lupus nephritis (LN) is a severe symptom of systemic lupus erythematosus and miR-21-5p is upregulated during LN. In the current study, the effects of pioglitazone (Pg), a peroxisome proliferator-activated receptor-γ (PPARγ) agonist, on LN development were assessed and explained by focusing miR-21-5p/TIMP3 axis. The expressions of miR-21-5p and PPARγ in LN mice were detected and then the mice were treated with pioglitazone to evaluate the anti-LN effects of agent. The miR-21-5p level was induced in MRL/lpr mice to confirm the central role of miR-21-5p inhibition in the protective effects of Pg against LN. The level of miR-21-5p was upregulated, while the level of PPARγ was downregulated in MRL/lpr mice. Pg inhibited miR-21-5p in renal tissues, which induced the expression of TIMP3. The changes in miR-21-5p/TIMP3 axis led to the improvements in renal structure and function, and inhibited autoimmune response. The induction of miR-21-5p impaired the effects of Pg, along with the suppression of TIMP3. The expression of miR-21-5p was associated with the progression of LN, contributing to the suppression of TIMP3 and development of LN. The inhibition of the miR-21-5p by Pg would restore the structure and function of kidneys in LN mice via the activation of PPARγ.