PPARγ Agonist Treatment Research Articles

Anaplastic thyroid carcinoma: a genome-based search for new targeted therapy options

Abstract Introduction/Objective Anaplastic thyroid carcinoma (ATC) is a rare, aggressive thyroid cancer. Precision medicine, particularly gene-targeted therapy has emerged as a promising avenue in cancer treatment. However, few targeted therapies have been approved for ATC. Here, we present a genome-based search for new targeted therapy options using next-generation sequencing (NGS) data of 727 ATC cases. Methods/Case Report Deidentified NGS results in 727 ATC cases were obtained from Foundation Medicine. A search of the literature and genomic databases (TCGA, My Cancer Genome, and DGIdb) was performed to analyzed frequency of gene mutations and corresponding gene targeted drugs. Results (if a Case Study enter NA) Remarkably, 99.17% of the 727 ATC cases had at least one targeted drug option available. Among the 254 unique genes identified with pathogenic mutations, 150 (59.06%) were found to have at least 1 corresponding targeted drug. Among the top 35 most frequently mutated genes (frequency > 2.0%), 27 (80.00%) had available targeted therapies. Notably, most drug categories (70.83%) exhibited multi-gene targeting capabilities. The drug categories based on the percentage of genes targeted from highest to lowest are Serine/Threonine and Tryosine kinase inhibitors, therapeutic antibodies, MEK inhibitors, CDK inhibitors, AKT inhibitors, PI3K inhibitors and immunotherapies. There are an additional 16 drug categories that target 1 to 5 of the 35 frequently mutated genes identified. Of particular interest is MTAP, a previously unreported frequently mutated gene which is most often deleted (14.77%). Several drugs are undergoing phase 1 and/or phase 2 clinical trials for MTAP-deleted solid tumors. MTAP loss holds promise for identifying expanding therapeutic options in ATC. Conclusion Our genome-based analysis indicates that 99.17% of the 727 ATC cases have targeted drug options, targeting 59.06% of identified gene mutations. Among the 24 categories of targeted drugs 17 (70.83%) target more than one gene. The 2018 FDA approval of combination BRAF/MEK inhibitor therapy for management of BRAF V600E-positive ATC was a major first step in gene targeted therapies. Besides that, Tyrosine kinase inhibitors, mTOR inhibitor, PPAR-γ agonist, ALK inhibitor, VEGF inhibitor and several combined treatment and immunotherapeutic agents are currently being tested in ATC clinical trials. These promising findings highlight the expanding repertoire of gene-targeted therapy options in ATC and emphasizes the importance of combined strategies and identifying driver mutations.

PPARγ agonist treatment reduces fibroadipose tissue in secondary lymphedema by exhausting fibroadipogenic PDGFRα+ mesenchymal cells.

Secondary lymphedema occurs in up to 20% of patients after lymphadenectomy performed for the surgical management of tumors involving the breast, prostate, uterus, and skin. Patients develop progressive edema of the affected extremity due to retention of protein-rich lymphatic fluid. Despite compression therapy, patients progress to chronic lymphedema in which noncompressible fibrosis and adipose tissue are deposited within the extremity. The presence of fibrosis led to our hypothesis that rosiglitazone, a PPARγ agonist that inhibits fibrosis, would reduce fibrosis in a mouse model of secondary lymphedema after hind limb lymphadenectomy. In vivo, rosiglitazone reduced fibrosis in the hind limb after lymphadenectomy. Our findings verified that rosiglitazone reestablished the adipogenic features of TGF-β1-treated mesenchymal cells in vitro. Despite this, rosiglitazone led to a reduction in adipose tissue deposition. Single-cell RNA-Seq data obtained from human tissues and flow cytometric and histological evaluation of mouse tissues demonstrated increased presence of PDGFRα+ cells in lymphedema; human tissue analysis verified these cells have the capacity for adipogenic and fibrogenic differentiation. Upon treatment with rosiglitazone, we noted a reduction in the overall quantity of PDGFRα+ cells and LipidTOX+ cells. Our findings provide a framework for treating secondary lymphedema as a condition of fibrosis and adipose tissue deposition, both of which, paradoxically, can be prevented with a pro-adipogenic agent.

FRI026 PPARγ Antagonists Induce Aromatase Transcription In Human Adipose Tissue Cells

Abstract Disclosure: J. Ardenkjær-Skinnerup: None. P.S. Petersen: None. N. Hadrup: None. G. Ravn-Haren: None. B. Emanuelli: None. U.B. Vogel: None. K.A. Brown: None. Peroxisome proliferator-activated receptor gamma (PPARγ) activation in adipose stromal cells (ASCs; adipocyte precursors) is associated with decreased expression of the estrogen biosynthetic enzyme, aromatase, encoded by the CYP19A1 gene. A number of chemicals and endocrine disruptors can affect PPARγ function. For example, ethanol-mediated inhibition of PPARγ activity is associated with increased risk of breast cancer,1 and a potential mechanism has been suggested to involve upregulation of aromatase. It is therefore hypothesized that inhibitors of PPARγ will induce aromatase expression and may act as breast carcinogens. This study aimed to explore the effect of PPARγ antagonists on the expression of aromatase in cells from human adipose tissue. Human adipose tissue was obtained from abdominoplasty or reduction mammoplasty surgeries. Explants, adipocytes and ASCs were collected for culture and/or gene expression analysis. Primary ASCs and the hTERT A41 hWAT ASC line were differentiated in the presence of PPARγ antagonists followed by gene expression analysis or lipid staining. Adipose tissue explants and A41 cells were treated for 24 or 48 h with PPARγ agonist or antagonist, and gene expression analysis was performed. Finally, PPARγ was overexpressed in A41 cells and/or treated with a PPARγ agonist to study the effect of PPARγ protein level and activation on aromatase expression. Aromatase expression was higher in human ASCs than in mature adipocytes. Exposure of ASCs to PPARγ antagonists during differentiation inhibited lipid accumulation and resulted in higher expression of aromatase. PPARγ overexpression and agonist treatment repressed aromatase expression in A41 cells, while antagonist treatment in differentiated A41 cells resulted in increased aromatase expression. A similar tendency was observed in adipose tissue explants. In conclusion, the results suggest that PPARγ regulates aromatase through two separate mechanisms. Exposure of human ASCs to PPARγ antagonists indirectly upregulates aromatase expression by inhibition of adipogenesis. In addition, PPARγ regulates aromatase in differentiated ASCs via a more acute mechanism, not related to adipocyte differentiation. 1. Petersen RK, Larsen SB, Jensen DM, et al. PPARgamma-PGC-1alpha activity is determinant of alcohol related breast cancer. Cancer Lett. 2012;315(1):59-68. Presentation: Friday, June 16, 2023

Transcriptional regulation of adipogenin expression in liver steatosis by hepatic peroxisome proliferator-activated receptor gamma.

The nuclear receptors peroxisome proliferator-activated receptor gamma (PPARγ) and adipogenin (ADIG) play vital roles in lipid metabolism. However, the interaction between PPARγ and ADIG during liver steatosis remains unclear. In this study, we aimed to investigate the role of PPARγ in the transcriptional regulation of hepatic ADIG expression. Adig was found to be highly expressed in various fatty liver mouse models. Although hepatic Adig was expressed at high levels in the fatty liver of type 2 diabetic ob/ob mice and was upregulated by PPARγ agonist treatment, it was expressed at significantly low levels in liver-specific Pparg-knockout mice. Moreover, hepatic Adig expression was observed in other mouse models of liver steatosis, such as the leptin receptor mutant db/db and alcohol-fed mice. Adig was also highly expressed in the white and brown adipose tissues, skeletal muscles, and heart of ob/ob mice. Reporter and electromobility shift assays showed that PPARγ positively regulates Adig transcriptional activity by directly binding to a functional PPARγ-responsive element in the promoter region. Our results indicate that Adig is a novel target gene of hepatic PPARγ in liver steatosis.

Prostaglandin D2 receptor expression in the lung and the effect of PPAR-γ, DP1, and DP2 receptor agonist treatment during respiratory viral infection

Abstract Prostaglandin D2 (PGD2) may play an anti-inflammatory role in the lung during respiratory viral infection, but little is known about the expression of its receptors (PPAR-γ, DP1, and DP2) in the lung or its mechanism of action. Adult C57BL/6 mice were infected with Sendai virus (500 pfu /g body weight), a natural mouse pathogen that infects airway epithelial cells. Immunostaining of uninfected lungs showed PPAR-γ protein in epithelial cells of larger airways, but not in the alveolar epithelial cells. After viral infection, PPAR-γ protein was no longer detectable in the lungs. Immunofluorescence showed DP1 present in parenchymal cells as well as in some CCSP+ airway epithelial cells, but levels did not appear to change during infection. DP2 expression increased after viral infection and was predominantly in CCSP+ epithelial cells 24 hours post-infection. DP2 also co-localized with MHC Class II+ cells in the parenchyma on days 3 and 7 post-infection. Viral infection of primary tracheal epithelial cells showed PPAR-γ mRNA expression was increased 48 and 72 hours post-infection. There was no change in DP1 or DP2 expression in vitro. To test the effect of each receptor in vivo, mice were infected and treated with PPAR-γ, DP1, and DP2 agonists, or vehicle every 12 hours. Mice treated with the PPAR-γ agonist were protected from body weight loss and had reduced IFN-γ expression on day 7, suggesting that PGD2 may be acting via PPAR-γ to reduce inflammation in the lung. Supported by grants from Sigma Xi Grant in Aid of Research and Saint Louis University College of Arts and Sciences Brennan Award.

Comparison of ANP and BNP Granular Density in Atria of Rats After Physiological and Pathological Hypertrophy.

Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) are cardiac hormones located in atria granules. Both peptides respond to cardiac pressure and volume dynamics and accordingly serve as translation biomarkers for the clinical treatment of heart failure. Serum ANP and BNP play central secretary roles in blood pressure and cardiac output regulation and have proven utility as differential biomarkers of cardiovascular proficiency and drug-induced maladaptation, yet both peptides are impervious to exercise-induced hypertrophy. We employed immunoelectron microscopy to examine the effects of 28 days of chronic swim exercise or administration of a PPARγ agonist on atrial granules and their stored natriuretic peptides in Sprague Dawley rats. Chronic swimming and drug treatment both resulted in a 15% increase in heart weight compared with controls, with no treatment effects on perinuclear granule area in the left atria (LAs). Drug treatment resulted in larger size granules with greater BNP density in the right atria. Comparing swimming and PPARγ agonist treatment effects on ANP:BNP granule density ratios between atrial chambers revealed a shift toward a greater proportion of ANP than BNP in LAs of swim-trained rats. These data suggest a distinction in the population of ANP and BNP after chronic swim or PPARγ that makes it a novel metric for the differentiation of pathological and physiological hypertrophy.

Docosahexaenoic Acid Alleviates Palmitic Acid-Induced Inflammation of Macrophages via TLR22-MAPK-PPARγ/Nrf2 Pathway in Large Yellow Croaker (Larimichthys crocea)

Palmitic acid (PA) is a saturated fatty acid (SFA) that can cause an inflammatory response, while docosahexaenoic acid (DHA) is always used as a nutritional modulator due to its anti-inflammatory properties. However, the potential molecular mechanism is still not completely elucidated in fish. Herein, the PA treatment induced an inflammatory response in macrophages of large yellow croaker (Larimichthys crocea). Meanwhile, the mRNA expression of Toll-like receptor (TLR)-related genes, especially tlr22, and the phosphorylation of the mitogen-activated protein kinase (MAPK) pathway were significantly upregulated by PA. Further investigation found that the PA-induced inflammatory response was suppressed by tlr22 knockdown and MAPK inhibitors. Moreover, the results of the peroxisome proliferator-activated receptor γ (PPARγ) agonist and inhibitor treatment proved that PPARγ was involved in the PA-induced inflammation. PA treatment decreased the protein expression of PPARγ, while tlr22 knockdown and MAPK inhibitors recovered the decreased expression. Besides, the PA-induced activation of Nrf2 was regulated by p38 MAPK. Furthermore, DHA-executed anti-inflammatory effects by regulating the phosphorylation of the MAPK pathway and expressions of PPARγ and Nrf2. Overall, the present study revealed that DHA alleviated PA-induced inflammation in macrophages via the TLR22-MAPK-PPARγ/Nrf2 pathway. These results could advance the understanding of the molecular mechanism of the SFA-induced inflammatory response and provide nutritional mitigative strategies.

A randomized phase 1b cross-over study of the safety of low-dose pioglitazone for treatment of autosomal dominant polycystic kidney disease.

BackgroundAutosomal dominant polycystic kidney disease (ADPKD) is one of the most common monogenetic disorders in humans and is characterized by numerous fluid-filled cysts that grow slowly, resulting in end-stage renal disease in the majority of patients. Preclinical studies have indicated that treatment with low-dose thiazolidinediones, such as pioglitazone, decrease cyst growth in rodent models of PKD.MethodsThis Phase 1b cross-over study compared the safety of treatment with a low dose (15 mg) of the peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist pioglitazone or placebo in PKD patients, with each treatment given for 1 year. The study monitored known side effects of PPAR-γ agonist treatment, including fluid retention and edema. Liver enzymes and risk of hypoglycemia were assessed throughout the study. As a secondary objective, the efficacy of low-dose pioglitazone was followed using a primary assessment of total kidney volume (TKV), blood pressure (BP) and kidney function.ResultsEighteen patients were randomized and 15 completed both arms. Compared with placebo, allocation to pioglitazone resulted in a significant decrease in total body water as assessed by bioimpedance analysis {mean difference 0.16 Ω [95% confidence interval (CI) 0.24–2.96], P = 0.024} and no differences in episodes of heart failure, clinical edema or change in echocardiography. Allocation to pioglitazone led to no difference in the percent change in TKV of −3.5% (95% CI −8.4–1.4, P = 0.14), diastolic BP and microalbumin:creatinine ratio.ConclusionsIn this small pilot trial in people with ADPKD but without diabetes, pioglitazone 15 mg was found to be as safe as placebo. Larger and longer-term randomized trials powered to assess effects on TKV are needed.

Pathological changes of frozen shoulder in rat model and the therapeutic effect of PPAR-γ agonist.

Frozen shoulder is a common shoulder disorder characterized by a gradual increase of pain and a limited range of motion. However, its pathophysiologic mechanisms remain unclear and there is no consensus as to the most effective treatment. The purpose of the study was to investigate the effect of transforming growth factor-β (TGF-β)on fibrosis and inflammatory response of the shoulder joint of rat models and to explore the therapeutic effect of the peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist. In the study, the effect of PPAR-γ agonist CDDO-IM treatment on cell proliferation, migration, and extracellular matrix proteins synthesis (vimentin, α-smooth muscle actin, collagen I, and collagen III) were tested by cell proliferation test, scratches test, real-time quantitative polymerase chain reaction, and Western blot analysis. The frozen shoulder was also established on the rat model by injecting adenovirus-TGF-β1 into rats' shoulder capsule. Pathological changes of the frozen shoulder tissue of the experimental group and PPAR-γ agonist treatment group were evaluated. The stiffness of joints of the three groups was tested. Inflammatory mediators' expression including cyclooxygenase-1, interleukin-1β, and tumor necrosis factor-α of the shoulder was tested by enzyme-linked immunosorbent assay, and the expression of extracellular matrix proteins was evaluated by hematoxylin and eosinstaining and immunohistochemistry. The results showed that pathological changes of the frozen shoulder in the rat model include an abnormal proliferation of fibroblasts, infiltration of inflammatory cells, and disorder of fibrous structure, while rosiglitazone reduced the severity of the frozen shoulder in the treatment group. Clinically, PPAR-γ agonists may be a promising target for the treatment of the frozen shoulder.

Building and Testing PPARγ Therapeutic ELB00824 with an Improved Therapeutic Window for Neuropathic Pain.

Effective, non-addictive therapeutics for chronic pain remain a critical need. While there are several potential therapeutics that stimulate anti-inflammatory mechanisms to restore homeostasis in the spinal dorsal horn microenvironment, the effectiveness of drugs for neuropathic pain are still inadequate. The convergence of increasing knowledge about the multi-factorial mechanisms underlying neuropathic pain and the mechanisms of drug action from preclinical studies are providing the ability to create pharmaceuticals with better clinical effectiveness. By targeting and activating the peroxisome proliferator-activated receptor gamma subunit (PPARγ), numerous preclinical studies report pleiotropic effects of thiazolidinediones (TDZ) beyond their intended use of increasing insulin, including their anti-inflammatory, renal, cardioprotective, and oncopreventative effects. Several studies find TDZs reduce pain-related behavioral symptoms, including ongoing secondary hypersensitivity driven by central sensitization. Previous studies find increased PPARγ in the spinal cord and brain regions innervated by incoming afferent nerve endings after the induction of neuropathic pain models. PPARγ agonist treatment provides an effective reduction in pain-related behaviors, including anxiety. Data further suggest that improved brain mitochondrial bioenergetics after PPARγ agonist treatment is a key mechanism for reducing hypersensitivity. This review emphasizes two points relevant for the development of better chronic pain therapies. First, employing neuropathic pain models with chronic duration is critical since they can encompass the continuum of molecular and brain circuitry alterations arising over time when pain persists, providing greater relevance to clinical pain syndromes. Assisting in that effort are preclinical models of chronic trigeminal pain syndromes. Secondly, considering the access to nerve and brain neurons and glia across the blood–brain barrier is important. While many therapies have low brain penetrance, a PPARγ agonist with better brain penetrance, ELB00824, has been developed. Purposeful design and recent comparative testing indicate that ELB00824 is extraordinarily efficient and efficacious. ELB00824 provides greatly improved attenuation of pain-related behaviors, including mechanical hypersensitivity, anxiety, and depression in our chronic trigeminal nerve injury models. Physiochemical properties allowing significant brain access and toxicity testing are discussed.

Analyses of alveolar epithelial injury via lipid-related stress in mammalian target of rapamycin inhibitor-induced lung disease

Although mammalian target of rapamycin inhibitors (mTORi) are used to treat various malignancies, they frequently induce active alveolitis and dyslipidemia. Abnormal lipid metabolism affects alveolar surfactant function and results in pulmonary disorders; however, the pathophysiology of lung injury and its relationship with lipid metabolism remain unknown. We investigated the relationship between lipid metabolism and alveolar epithelial injury, focusing on peroxisome proliferator-activated receptor-γ (PPAR-γ) as a lipid stress-related factor in mTORi-induced lung injury. We clinicopathologically examined three patients with mTORi-induced lung injury. We constructed an mTORi injury mouse model using temsirolimus in mice (30 mg/kg/day), with the vehicle control and bleomycin injury groups. We also constructed a cultured alveolar epithelial cell injury model using temsirolimus (0–40 μM) in the mouse lung epithelial cell line MLE-12 and performed analysis with or without pioglitazone (PPAR-γ agonist) treatment. All three patients had dyslipidemia and lung lesions of hyperplastic pneumocytes with foamy and enlarged changes. In the mouse model, temsirolimus induced significantly higher levels of total cholesterol and free fatty acids in serum and higher levels of surfactant protein D in serum and BAL fluid with an increase in inflammatory cytokines in the lung compared to control. Temsirolimus also induced hyperplastic foamy pneumocytes with increased lipid-associated spots and larger round electron-lucent bodies compared to the control or bleomycin groups in microscopic analyses. Multiple lipid-associated spots within the cytoplasm were also induced by temsirolimus administration in MLE-12 cells. Temsirolimus downregulated PPAR-γ expression in mouse lung and MLE-12 cells but upregulated cleaved caspase-3 in MLE-12 cells. Pioglitazone blocked the upregulated cleaved caspase-3 expression in MLE-12 cells. The pathogenesis of mTORi-induced lung disease may be involved in alveolar epithelial injury, via lipid metabolic stress associated with downregulated PPAR-γ expression. Focusing on the relationship between lipid metabolic stress and alveolar epithelial injury represents a potentially novel approach to the study of pulmonary damage.

Effect of PPARγ agonist on aerobic exercise capacity in relation to body fat distribution in men with type 2 diabetes mellitus and coronary artery disease: a 1-yr randomized study.

Targeting metabolic determinants of exercise performance with pharmacological agents that would mimic/potentiate the effects of exercise represents an attractive clinical alternative to counterbalance the poor exercise capacity in patients with type 2 diabetes mellitus (T2DM). We examined the effect of 1-yr treatment with the insulin sensitizer peroxisome proliferator-activated receptor (PPAR)γ agonist rosiglitazone on aerobic exercise capacity and body fat composition/distribution in men with T2DM and stable coronary artery disease (CAD). One-hundred four men (age: 64 ± 7 yr; body mass index: 30.0 ± 4.4 kg/m2) with T2DM and CAD were randomized to receive rosiglitazone or placebo for 1 yr. Aerobic exercise capacity (exercise duration) was assessed with a maximal treadmill test, and body composition/distribution were assessed by dual-energy X-ray absorptiometry/computed tomography scans. At 1 yr, patients with T2DM under PPARγ agonist treatment showed a reduction in aerobic exercise capacity compared with the control group (exercise duration change, -31 ± 8 versus 7 ± 11 s, P = 0.009). Significant increases in body fat mass (3.1 ± 0.4 kg, 12%), abdominal and mid-thigh subcutaneous adipose tissue (AT) levels, and mid-thigh skeletal muscle fat were found (all P < 0.01), whereas no effect on visceral AT levels was observed (P > 0.05) under treatment. Subcutaneous fat mass gained under PPARγ agonist was the strongest predictor of the worsening in aerobic exercise capacity (P > 0.0001); no association was found with skeletal muscle fat infiltration nor visceral AT. Treatment with the insulin sensitizer PPARγ agonist rosiglitazone in patients with T2DM and CAD is associated with a worsening in aerobic exercise capacity, which seems to be mainly attributable to weight gain and subcutaneous fat mass expansion.

Peroxisome Proliferator-Activated Receptor-γ Prevents Cholesterol Gallstone Formation in C57bl Mice by Regulating Bile Acid Synthesis and Enterohepatic Circulation.

To investigate the role of the peroxisome proliferator-activated receptor-γ (PPARγ) in the progression of cholesterol gallstone disease (CGD), C57bl/6J mice were randomized to the following groups (n=7/group): L (lithogenic diet, LGD), LM (LGD+pioglitazone), CM (chow diet+pioglitazone), and NC (normal control, chow diet). Gallbladder stones were observed by microscopy. Histological gallbladder changes were assessed. Bile acids (BA) and cholesterol were measured in the serum, bile, and feces. Proteins and mRNA expression of genes involved in BA metabolism and enterohepatic circulation were assessed by western blotting and real-time RT-PCR. PPARγ activation was performed in LO2 cell by lentivirus transfection and in Caco2 cell by PPARγ agonist treatment. Downregulation of farnesoid X receptor (FXR) by small interference RNA (siRNA) was performed in L02 cells and Caco2 cells, respectively. Results showed that pharmacological activation of PPARγ by pioglitazone prevents cholesterol gallstone formation by increasing biliary BA synthesis and enterohepatic circulation. Activated PPARγ induced the expression of genes involved in enterohepatic circulation and bile acid synthesis (like PCG1α, BSEP, MRP2, MRP3, MRP4, NTCP, CYP7A1, CYP27A1, ASBT, OSTα, and OSTβ). Downregulation of FXR repressed expression of partial genes involved in BA enterohepatic circulation. These findings suggest a new function of PPARγ in preventing CGD by handling BA synthesis and transport through a FXR dependent or independent pathway.

The peroxisome proliferator-activated receptor gamma agonist pioglitazone improves nitric oxide availability, renin-angiotensin system and aberrant redox regulation in the kidney of pre-hypertensive rats.

The peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-dependent nuclear receptor. It plays an important role in kidney physiology, where it might contribute to arterial blood pressure regulation and hypertension development by modulation of several signaling pathways. In our study we focused on the effect of PPARγ agonist pioglitazone on changes in the nitric oxide synthase (NOS) expression and activity, the renin-angiotensin system (RAS) cascade, and redox homeostasis signaling pathways in the renal cortex of young pre hypertensive rat models. Young (5-weeks old) spontaneously hypertensive (SHR) and borderline hypertensive (BHR) rats were treated by pioglitazone (PIO, 10 mg/kg/day) during 10 days. Blood pressure (BP) was determined by plethysmography method. Changes in lipid profile were detected in plasma with standard kits using biochemical analyser. Gene expression has been detected by qRT-PCR and protein level was determined using Western blot analysis. Superoxide dismutase (SOD) and catalase (CAT) activities were determined spectrophotometrically and the total enzyme activity of NOS was measured using a radioactive assay based on conversion of [3H] L-arginine to [3H] L- citrulline. Administration of pioglitazone decreased BP in BHR and slowed down the development of BP increase in young SHR animals. For NOS, activation by PPARγ correlated with increase in gene and protein expression of NOS isoforms and in total enzyme activity both in BHR and SHR. In the AT1R/Nox pathway, the treatment did not significantly influence mRNA expression of the p22phox subunit of NADPH oxidase (Nox) and AT1R, but up-regulated the 'pro-vasodilatatory' Mas and AT2R receptors in both BHR and SHR groups. Pioglitazone treatment affected redox regulation. Increase in gene expression of nuclear factor E2-related factor 2 (Nrf2) and SOD isoforms correlated with SOD and CAT enzyme activities. The group treatment-to-control ratios, BHR Pioglitazone to BHR control and SHR Pioglitazone to SHR control for gene expression increased by 10% to 230%. The largest effect of PPARγ has been observed in SOD1, SOD3 and the Mas receptor gene treatment-to-control ratios. The most prominent differences between BHR and SHR were observed in SOD1 and Mas receptor expressions, with large effects of opposite sign in BHR versus SHR. Our data indicate that an increase of NO release activates signaling in the renal cortex of pre-hypertensive rats after pioglitazone treatment. Improvement of NO availability, AT2R, Mas receptors and aberrant redox regulation is thought to be the major correlated mechanisms mediating the BP decrease affected by the PPARγ agonist treatment. We also observed that the most sensitive tissue responses to PPARγ-dependent activation of Nrf2 have been primarily found in the kidney of young hypertensive animals.

PPAR-γ Agonist Promotes Proliferation of Neural Stem Cells Via Mitophagy Inhibition

Background: Proliferation of neural stem cells (NSCs) is crucial for recovery from spinal cord injury (SCI). The effect of PPAR-γ agonist on SCI recovery and the way it regulating NSCs proliferation are both unknown. Methods: The effects of PPAR-γ agonist (rosiglitazone) treatment on recovery from SCI and proliferation of NSCs were confirmed. The roles of mitophagy and PTEN induced putative kinase 1 (PINK1) in rosiglitazoneinduced proliferation of NSCs were explored. Details mechanisms on the transcription regulation of PINK1 by rosiglitazone were addressed. Findings: Rosiglitazone independently increased the proportion of Nestin /Brdu cells in the spinal cord and motor function of SCI rats. It reduced mitophagy and expression of PTEN induced putative kinase 1 (PINK1) in NSCs. The forkhead box protein O1 (FOXO1) was identified as the transcription factor mostly altered by rosiglitazone. Restoration of FOXO1 expression antagonized the effects of rosiglitazone on mitophagy and PINK1 expression. The FOXO1 consensus sequence (FCS) was not identified upstream of the PINK1 transcription start site, but three FCSs were found in the first intron of the PINK1 gene. All of the FCSs participated in the regulation of PINK1 transcription upon treatment with rosiglitazone and expression of FOXO1 but the proximal FCS (chr 5: 156680169-156680185, 3022 bp counting from the translation start site) exerted greater influence. Conclusions: PPAR-γ agonist could be a promising therapeutic strategy for spinal cord injury. Funding Statement:This work was supported by the National Natural Science Foundation of China (Grant No. 81870334, 81301038, 81300071, 81300279 and 81741067); the Science and Technology Program of Guangdong (Grant No. 2015A020212029); and the Science and Technology Program of Guangzhou City (Grant No. 201510010048, 201607010009, 201607010010 and 201804010050). Declaration of Interests: All authors declare no potential conflict of interest. Ethics Approval Statement: All of the animal experiments complied with the ARRIVE guidelines, and they were carried out in accordance with the National Institutes of Health Guide for the Care and Use of Laboratory Animals (NIH Publication No. 8023, revised 1978)

Rosiglitazone lowers resting and blood pressure response to exercise in men with type 2 diabetes: A 1-year randomized study.

We aimed to determine the effect of 1-year treatment with the insulin sensitizer peroxisome proliferator-activated receptor (PPAR)-γ agonist rosiglitazone on exercise capacity and blood pressure (BP) response to exercise in men with coronary artery disease (CAD) and type 2 diabetes (T2D). A total of 116 men (age, 64 ± 7 years; body mass index, 30.0 ± 4.4 kg/m2 ) with CAD and T2D were randomized to receive rosiglitazone or placebo for 1 year. Exercise capacity (VO2peak ) and BP response to exercise were assessed with a maximal treadmill test, prior to the intervention and at 1-year follow-up. Exercise-induced hypertension (EIH) was defined as maximal systolic BP ≥ 220 mm Hg and/or diastolic BP ≥ 100 mm Hg. PPAR-γ agonist-treated patients showed improvements in fasting glucose, HbA1c and insulin sensitivity (Homeostasis model assessment of insulin resistance [HOMA-IR]) (all P < .05). Resting BPs, maximal exercise diastolic BP and resting rate-pressure product (RPP) were all reduced in the PPAR-γ agonist group (P < .05). Maximal exercise duration was unchanged. T2D patients who displayed the greatest improvement in insulin sensitivity (HOMA-IR) under PPAR-γ agonist treatment experienced a greater reduction in exercise BP and RPP (P < .05). The proportion of men with EIH decreased in the PPAR-γ agonist group during follow-up (39.00% ± 0.06% vs 21.00% ± 0.05%). In the subgroup with EIH that was treated with a PPAR-γ agonist, resting and exercise diastolic BP, as well as resting RPP, were all reduced at 1-year follow-up (P < .05). The insulin sensitizer rosiglitazone has a beneficial effect on resting and BP response to exercise in men with CAD and T2D, especially in those with an exaggerated BP response to exercise.

Demyelination in Multiple Sclerosis: Reprogramming Energy Metabolism and Potential PPARγ Agonist Treatment Approaches.

Demyelination in multiple sclerosis (MS) cells is the site of several energy metabolic abnormalities driven by dysregulation between the opposed interplay of peroxisome proliferator-activated receptor γ (PPARγ) and WNT/β-catenin pathways. We focus our review on the opposing interactions observed in demyelinating processes in MS between the canonical WNT/β-catenin pathway and PPARγ and their reprogramming energy metabolism implications. Demyelination in MS is associated with chronic inflammation, which is itself associated with the release of cytokines by CD4+ Th17 cells, and downregulation of PPARγ expression leading to the upregulation of the WNT/β-catenin pathway. Upregulation of WNT/β-catenin signaling induces activation of glycolytic enzymes that modify their energy metabolic behavior. Then, in MS cells, a large portion of cytosolic pyruvate is converted into lactate. This phenomenon is called the Warburg effect, despite the availability of oxygen. The Warburg effect is the shift of an energy transfer production from mitochondrial oxidative phosphorylation to aerobic glycolysis. Lactate production is correlated with increased WNT/β-catenin signaling and demyelinating processes by inducing dysfunction of CD4+ T cells leading to axonal and neuronal damage. In MS, downregulation of PPARγ decreases insulin sensitivity and increases neuroinflammation. PPARγ agonists inhibit Th17 differentiation in CD4+ T cells and then diminish release of cytokines. In MS, abnormalities in the regulation of circadian rhythms stimulate the WNT pathway to initiate the demyelination process. Moreover, PPARγ contributes to the regulation of some key circadian genes. Thus, PPARγ agonists interfere with reprogramming energy metabolism by directly inhibiting the WNT/β-catenin pathway and circadian rhythms and could appear as promising treatments in MS due to these interactions.

Regulation of the placental BCRP transporter by PPAR gamma.

Identifying regulators of placental breast cancer resistance protein (BCRP) expression is critical as downregulation of this transporter may increase exposure of the fetus to xenobiotics. Here, we sought to test whether the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) regulates BCRP expression in the placenta. To test this, human BeWo placental choriocarcinoma cells were cultured with the PPARγ agonist rosiglitazone or the PPARγ antagonist T0070907 for 24h. Messenger RNA (mRNA) expression of syncytialization markers, GCM1 and hCGβ, as well as BCRP increased with PPARγ agonist treatment. Conversely, BCRP mRNA and protein expression decreased 30%-50% with PPARγ antagonist treatment. Rosiglitazone enhanced BCRP protein expression and transport activity, resulting in a 20% greater efflux of the substrate Hoechst 33342 compared with control cells. These results suggest that PPARγ can upregulate BCRP expression in the placenta, which may be important in understanding mechanisms that protect the fetus from xenobiotic exposure during development.

PPARγ is regulated by miR-27b-3p negatively and plays an important role in porcine oocyte maturation

To elucidate the key miRNAs and the signalling pathways that are involved in porcine oocyte maturation, we performed a deep sequencing analysis of the miRNAs of pig germinal vesicle (GV) oocytes and metaphase II (MII) oocytes. Seven differentially expressed (DE) miRNAs were identified and the expression levels of miR-21 and miR-27b-3p were further confirmed by QPCR analysis. The target genes of 7 DE miRNAs were predicted and subjected to pathway analysis. Interestingly, fatty acid metabolism and fatty acid biosynthesis were the top two significantly enriched molecular functions during oocyte maturation. Heat map, which was built with 7 DE miRNAs and the enriched the molecular functions, revealed that miR-21, miR-27b-3p, miR-10a-5p and miR-10b-5p were involved in fatty acid metabolism. In particular, the regulatory role of miR-27b-3p on peroxisome proliferator-activated receptor-γ (PPARγ) was confirmed by their inversed expression patterns in GV and MII oocytes and luciferase report assays. In addition, we observed that PPARγ agonist (rosiglitazone) treatment significantly enhanced porcine oocyte maturation rate and early embryo developmental competent. Taken together, our results demonstrated that miR-27b and its target, PPARγ, play the vital roles in pig oocyte maturation through regulating the fatty acid metabolism. These data increased our understanding of the regulatory gene networks in porcine oocyte maturation and development.

Combined effect of honokiol and rosiglitazone on cell growth inhibition through enhanced G0/G1 phase arrest in hepatoma cells

BackgroundHonokiol, a derivative extracted from the stem and bark of Magnolia officinalis, has been reported to have anticancer effects in hepatoma cells. Recently, it was found that honokiol acted as not only a retinoid X receptor (RXR) agonist but also as a peroxisome proliferator-activated receptor gamma (PPARγ) agonist. Additionally, honokiol is capable of activating PPARγ/RXR heterodimers synergistically in the presence of rosiglitazone in 3T3-L1 adipocyte and HLE human hepatoma cells. Furthermore, synthetic PPARγ agonist thiazolidinediones exhibited growth inhibition effects in hepatoma cells through PPARγ-dependent and PPARγ-independent pathways. However, the combined effects of treatment with honokiol and PPARγ agonist are unclear in hepatoma cells. MethodsIn this study, sulforhodamine B assay, flow cytometry, and Western blot analysis were used to examine the combined effects of honokiol and PPARγ agonist (rosiglitazone) treatment on growth inhibition in SK-Hep1 and Mahlavu hepatoma cells. ResultsHonokiol or rosiglitazone treatment in hepatoma cells induced growth inhibition at high dose by sulforhodamine B assay. Moreover, we found that combined treatment with honokiol and rosiglitazone showed more effective growth inhibition in hepatoma cells than treatment with honokiol or rosiglitazone alone. Also, treatment with honokiol and rosiglitazone induced cell cycle arrest in the G0/G1 phase; increased p21; and decreased cyclin D1, cyclin E1, and Rb expression in SK-Hep1 hepatoma cells. ConclusionHonokiol combined with rosiglitazone showed more effective growth inhibition in hepatoma cells mediated through the regulation of G0/G1 phase-related proteins p21, cyclin D1, cyclin E1, and Rb and cell cycle progression.