PPARgamma Research Articles

PPARγ activation ameliorates cognitive impairment and chronic microglial activation in the aftermath of r-mTBI

Chronic neuroinflammation and microglial activation are key mediators of the secondary injury cascades and cognitive impairment that follow exposure to repetitive mild traumatic brain injury (r-mTBI). Peroxisome proliferator-activated receptor-γ (PPARγ) is expressed on microglia and brain resident myeloid cell types and their signaling plays a major anti-inflammatory role in modulating microglial responses. At chronic timepoints following injury, constitutive PPARγ signaling is thought to be dysregulated, thus releasing the inhibitory brakes on chronically activated microglia. Increasing evidence suggests that thiazolidinediones (TZDs), a class of compounds approved from the treatment of diabetes mellitus, effectively reduce neuroinflammation and chronic microglial activation by activating the peroxisome proliferator-activated receptor-γ (PPARγ). The present study used a closed-head r-mTBI model to investigate the influence of the TZD Pioglitazone on cognitive function and neuroinflammation in the aftermath of r-mTBI exposure. We revealed that Pioglitazone treatment attenuated spatial learning and memory impairments at 6 months post-injury and reduced the expression of reactive microglia and astrocyte markers in the cortex, hippocampus, and corpus callosum. We then examined whether Pioglitazone treatment altered inflammatory signaling mechanisms in isolated microglia and confirmed downregulation of proinflammatory transcription factors and cytokine levels. To further investigate microglial-specific mechanisms underlying PPARγ-mediated neuroprotection, we generated a novel tamoxifen-inducible microglial-specific PPARγ overexpression mouse line and examined its influence on microglial phenotype following injury. Using RNA sequencing, we revealed that PPARγ overexpression ameliorates microglial activation, promotes the activation of pathways associated with wound healing and tissue repair (such as: IL10, IL4 and NGF pathways), and inhibits the adoption of a disease-associated microglia-like (DAM-like) phenotype. This study provides insight into the role of PPARγ as a critical regulator of the neuroinflammatory cascade that follows r-mTBI in mice and demonstrates that the use of PPARγ agonists such as Pioglitazone and newer generation TZDs hold strong therapeutic potential to prevent the chronic neurodegenerative sequelae of r-mTBI.

Molecular Changes Implicate Angiogenesis and Arterial Remodeling in Systemic Sclerosis-Associated and Idiopathic Pulmonary Hypertension.

Pulmonary hypertension (PH) is a common complication of systemic sclerosis (SSc) and a leading cause of mortality among patients with this disease. PH can also occur as an idiopathic condition (idiopathic pulmonary arterial hypertension). Investigation of transcriptomic alterations in vascular populations is critical to elucidating cellular mechanisms underlying pathobiology of SSc-associated and idiopathic PH. We analyzed single-cell RNA sequencing profiles of endothelial and perivascular mesenchymal populations from explanted lung tissue of patients with SSc-associated PH (n=16), idiopathic pulmonary arterial hypertension (n=3), and healthy controls (n=15). Findings were validated by immunofluorescence staining of explanted human lung tissue. Three disease-associated endothelial populations emerged. Two angiogenic endothelial cell (EC) subtypes markedly expanded in SSc-associated PH lungs: tip ECs expressing canonical tip markers PGF and APLN and phalanx ECs expressing genes associated with vascular development, endothelial barrier integrity, and Notch signaling. Gene regulatory network analysis suggested enrichment of Smad1 (SMAD family member 1) and PPAR-γ (peroxisome proliferator-activated receptor-γ) regulon activities in these 2 populations, respectively. Mapping of potential ligand-receptor interactions highlighted Notch, apelin-APJ (apelin receptor), and angiopoietin-Tie (tyrosine kinase with immunoglobulin-like and EGF-like domains 1) signaling pathways between angiogenic ECs and perivascular cells. Transitional cells, expressing both endothelial and pericyte/smooth muscle cell markers, provided evidence for the presence of endothelial-to-mesenchymal transition. Transcriptional programs associated with arterial endothelial dysfunction implicated VEGF-A (vascular endothelial growth factor-A), TGF-β1 (transforming growth factor beta-1), angiotensin, and TNFSF12 (tumor necrosis factor ligand superfamily member 12)/TWEAK (TNF-related weak inducer of apoptosis) in the injury/remodeling phenotype of PH arterial ECs. These data provide high-resolution insights into the complexity and plasticity of the pulmonary endothelium in SSc-associated PH and idiopathic pulmonary arterial hypertension and provide direct molecular insights into soluble mediators and transcription factors driving PH vasculopathy.

A first-in-class selective inhibitor of EGFR and PI3K offers a single-molecule approach to targeting adaptive resistance

Despite tremendous progress in precision oncology, adaptive resistance mechanisms limit the long-term effectiveness of molecularly targeted agents. Here we evaluated the pharmacological profile of MTX-531 that was computationally designed to selectively target two key resistance drivers, epidermal growth factor receptor and phosphatidylinositol 3-OH kinase (PI3K). MTX-531 exhibits low-nanomolar potency against both targets with a high degree of specificity predicted by cocrystal structural analyses. MTX-531 monotherapy uniformly resulted in tumor regressions of squamous head and neck patient-derived xenograft (PDX) models. The combination of MTX-531 with mitogen-activated protein kinase kinase or KRAS-G12C inhibitors led to durable regressions of BRAF-mutant or KRAS-mutant colorectal cancer PDX models, resulting in striking increases in median survival. MTX-531 is exceptionally well tolerated in mice and uniquely does not lead to the hyperglycemia commonly seen with PI3K inhibitors. Here, we show that MTX-531 acts as a weak agonist of peroxisome proliferator-activated receptor-γ, an attribute that likely mitigates hyperglycemia induced by PI3K inhibition. This unique feature of MTX-531 confers a favorable therapeutic index not typically seen with PI3K inhibitors.

Molecular pathophysiology of secondary lymphedema.

Lymphedema occurs as a result of lymphatic vessel damage or obstruction, leading to the lymphatic fluid stasis, which triggers inflammation, tissue fibrosis, and adipose tissue deposition with adipocyte hypertrophy. The treatment of lymphedema is divided into conservative and surgical approaches. Among surgical treatments, methods like lymphaticovenular anastomosis and vascularized lymph node transfer are gaining attention as they focus on restoring lymphatic flow, constituting a physiologic treatment approach. Lymphatic endothelial cells form the structure of lymphatic vessels. These cells possess button-like junctions that facilitate the influx of fluid and leukocytes. Approximately 10% of interstitial fluid is connected to venous return through lymphatic capillaries. Damage to lymphatic vessels leads to lymphatic fluid stasis, resulting in the clinical condition of lymphedema through three mechanisms: Inflammation involving CD4+ T cells as the principal contributing factor, along with the effects of immune cells on the VEGF-C/VEGFR axis, consequently resulting in abnormal lymphangiogenesis; adipocyte hypertrophy and adipose tissue deposition regulated by the interaction of CCAAT/enhancer-binding protein α and peroxisome proliferator-activated receptor-γ; and tissue fibrosis initiated by the overactivity of Th2 cells, leading to the secretion of profibrotic cytokines such as IL-4, IL-13, and the growth factor TGF-β1. Surgical treatments aimed at reconstructing the lymphatic system help facilitate lymphatic fluid drainage, but their effectiveness in treating already damaged lymphatic vessels is limited. Therefore, reviewing the pathophysiology and molecular mechanisms of lymphedema is crucial to complement surgical treatments and explore novel therapeutic approaches.

Notoginsenoside Fc alleviates oxidized low-density lipoprotein-induced endothelial cell dysfunction and upregulates PPAR-γ in vitro.

Deep venous thrombosis (DVT) is a prevalent vascular disease and a major cause of morbidity and mortality worldwide. Notoginsenoside Fc (NFc) is a protopanaxadiol-type saponin that has been shown to have beneficial effects on several disorders. However, its function in DVT is unclear. Human umbilical vein endothelial cells (HUVECs) were treated with oxidized low-density lipoprotein (ox-LDL) to mimic DVT in vitro and treated with NFc to investigate its functions. CCK-8 assay was utilized for measuring cell viability. Western blotting was used for detecting protein levels of proinflammatory cytokines, apoptosis-related markers, and peroxisome proliferator-activated receptor-γ (PPAR-γ). Flow cytometry was performed for cell apoptosis detection. Levels of oxidative stress-related markers were examined by the DCFH-DA method and ELISA. RT-qPCR was utilized for the measurement of PPAR-γ mRNA level. NFc increased the viability and suppressed inflammation, apoptosis, and oxidative stress in ox-LDL-treated HUVECs. NFc treatment induced upregulation of PPAR-γ in HUVECs. NFc mitigates ox-LDL-induced dysfunction of HUVECs.

Silibinin Targeting Heat Shock Protein 90 Represents a Novel Approach to Alleviate Nonalcoholic Fatty Liver Disease by Simultaneously Lowering Hepatic Lipotoxicity and Enhancing Gut Barrier Function.

Nonalcoholic fatty liver disease (NAFLD) is a clinicopathological condition characterized by intrahepatic ectopic steatosis. Due to the increase in high-calorie diets and sedentary lifestyles, NAFLD has surpassed viral hepatitis and become the most prevalent chronic liver disease globally. Silibinin, a natural compound, has shown promising therapeutic potential for the treatment of liver diseases. Nevertheless, the ameliorative effects of silibinin on NAFLD have not been completely understood, and the underlying mechanism is elusive. Therefore, in this study, we used high-fat diet (HFD)-induced mice and free fatty acid (FFA)-stimulated HepG2 cells to investigate the efficacy of silibinin for the treatment of NAFLD and elucidate the underlying mechanisms. In vivo, silibinin showed significant efficacy in inhibiting adiposity, improving lipid profile levels, ameliorating hepatic histological aberrations, healing the intestinal epithelium, and restoring gut microbiota compositions. Furthermore, in vitro, silibinin effectively inhibited FFA-induced lipid accumulation in HepG2 cells. Mechanistically, we reveal that silibinin possesses the ability to ameliorate hepatic lipotoxicity by suppressing the heat shock protein 90 (Hsp90)/peroxisome proliferator-activated receptor-γ (PPARγ) pathway and alleviating gut dysfunction by inhibiting the Hsp90/NOD-like receptor pyrin domain-containing 3 (NLRP3) pathway. Altogether, our findings provide evidence that silibinin is a promising candidate for alleviating the "multiple-hit" in the progression of NAFLD.

Kaempferia parviflora extract and its component polymethoxyflavones suppress adipogenic differentiation of human bone marrow-derived mesenchymal stem cells via the AMPK pathway.

Kaempferia parviflora Wall. ex. Baker (KP) has been reported to exhibit anti-obesity effects. However, the detailed mechanism of the anti-obesity effect of KP extract (KPE) is yet to be clarified. Here, we investigated the effect of KPE and its component polymethoxyflavones (PMFs) on the adipogenic differentiation of human mesenchymal stem cells (MSCs). KPE and PMFs fraction (2.5µg/mL) significantly inhibited lipid and triacylglyceride accumulation in MSCs; lipid accumulation in MSCs was suppressed during the early stages of differentiation (days 0-3) but not during the mid (days 3-7) or late (days 7-14) stages. Treatment with KPE and PMFs fractions significantly suppressed peroxisome proliferator-activated receptor-γ (PPARγ), CCAAT/enhancer binding protein α (C/EBPα), and various adipogenic metabolic factors. Treatment with KPE and PMFs fraction induced the activation of AMP-activated protein kinase (AMPK) signaling, and pretreatment with an AMPK signaling inhibitor significantly attenuated KPE- and PMFs fraction-induced suppression of lipid formation. Our findings demonstrate that KPE and PMFs fraction inhibit lipid formation by inhibiting the differentiation of undifferentiated MSCs into adipocyte lineages via AMPK signaling, and this may be the mechanism underlying the anti-obesity effects of KPE and PMFs. Our study lays the foundation for the elucidation of the anti-obesity mechanism of KPE and PMFs.

Exploring the mechanism of Liang Xue Wu Hua Tang in the treatment of rosacea via network pharmacology and molecular docking.

Rosacea is a chronic and recurrent inflammatory skin disease affecting the center of the face that causes burning and itching sensations and changes in aesthetics. Liang Xue Wu Hua Tang (LXWHT) is a classic herbal formulation that is efficacious and has been widely used in the clinical treatment of rosacea; however, the pharmacological mechanisms remain unclear. The aim of the present study was to investigate the mechanism of action of LXWHT using network pharmacology and molecular docking. The Traditional Chinese Medicine System Pharmacology database was searched to identify the active ingredients and pharmacological targets of LXWHT, and the GeneCard, Disgenet, and Gene Expression Omnibus databases were applied to screen rosacea-related targets. Cytoscape software was used to visualize the protein-protein interaction network, and network topology analysis was used to identify core targets. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed for the core targets. Molecular docking simulations and visualization were performed using Maestro and PyMOL, respectively. A total of 43 active compounds and 28 potential targets for LXWHT treatment of rosacea were selected for analysis. The Gene Ontology/Kyoto Encyclopedia of Genes and Genomes results indicated that LXWHT may exert therapeutic effects on rosacea by intervening in immune pathways including tumor necrosis factor pathway, interleukin-17 pathways, and Toll-like receptor signaling pathways. Chemokine ligand 2, interferon-γ, interleukin-1ß, peroxisome proliferator-activated receptor-γ, and matrix metallopeptidase 9 may be the core therapeutic target. Quercetin, stigmasterol, kaempferol, beta-sitosterol, luteolin, beta-carotene, baicalein, acetin, and isorhamnetin were predicted to be the key active ingredients. LXWHT may exert therapeutic effects in the treatment of rosacea by modulating immunity and angiogenesis, laying the foundation for further research.

Resveratrol suppresses hepatic fatty acid synthesis and increases fatty acid β-oxidation via the microRNA-33/SIRT6 signaling pathway.

Hyperlipidemia is a strong risk factor for numerous diseases. Resveratrol (Res) is a non-flavonoid polyphenol organic compound with multiple biological functions. However, the specific molecular mechanism and its role in hepatic lipid metabolism remain unclear. Therefore, the aim of the present study was to elucidate the mechanism underlying how Res improves hepatic lipid metabolism by decreasing microRNA-33 (miR-33) levels. First, blood miR-33 expression in participants with hyperlipidemia was detected by reverse transcription-quantitative PCR, and the results revealed significant upregulation of miR-33 expression in hyperlipidemia. Additionally, after transfection of HepG2 cells with miR-33 mimics or inhibitor, western blot analysis indicated downregulation and upregulation, respectively, of the mRNA and protein expression levels of sirtuin 6 (SIRT6). Luciferase reporter analysis provided further evidence for binding of miR-33 with the SIRT6 3'-untranslated region. Furthermore, the levels of peroxisome proliferator-activated receptor-γ (PPARγ), PPARγ-coactivator 1α and carnitine palmitoyl transferase 1 were increased, while the concentration levels of acetyl-CoA carboxylase, fatty acid synthase and sterol regulatory element-binding protein 1 were decreased when SIRT6 was overexpressed. Notably, Res improved the basic metabolic parameters of mice fed a high-fat diet by regulating the miR-33/SIRT6 signaling pathway. Thus, it was demonstrated that the dysregulation of miR-33 could lead to lipid metabolism disorders, while Res improved lipid metabolism by regulating the expression of miR-33 and its target gene, SIRT6. Thus, Res can be used to prevent or treat hyperlipidemia and associated diseases clinically by suppressing hepatic fatty acid synthesis and increasing fatty acid β-oxidation.

Microglial forkhead box O3a deficiency attenuates LPS-induced neuro-inflammation and depressive-like behaviour through regulating the expression of peroxisome proliferator-activated receptor-γ.

Depression is closely linked with microglial activation and neuro-inflammation. Peroxisome proliferator-activated receptor-γ (PPAR-γ) plays an important role in M2 activation of microglia. Forkhead box (FOX) O3a has been implicated in the regulation of mood-relevant behaviour. However, little is known about the inflammatory mechanisms of in the microglia of the brain. Here, we have investigated the role of microglial FOXO3a/PPAR-γ in the development of depression. The effect of FOXO3a on microglia inflammation was analysed in vitro and in lipopolysaccharide (LPS)-induced depression-like behaviours in vivo. ChIP-seq and Dual-luciferase reporter assays were used to confirm the interaction between FOXO3a and PPAR-γ. Behavioural changes were measured, while inflammatory cytokines, microglial phenotype and morphological properties were determined by ELISA, qRT-PCR, western blotting and immunostaining. Overexpression of FOXO3a significantly attenuated expression of PPAR-γ and enhanced the microglial polarization towards the M1 phenotype, while knockdown of FOXO3a had the opposite effect. FOXO3a binds to the promoters of PPAR-γ and decreases its transcription activity. Importantly, deacetylation and activation of FOXO3a regulate LPS-induced neuro-inflammation by inhibiting the expression of PPAR-γ in microglia cells, supporting the antidepressant potential of histone deacetylase inhibitors. Microglial FOXO3a deficiency in mice alleviated LPS-induced neuro-inflammation and depression-like behaviours but failed to reduce anxiety behaviour, whereas pharmacological inhibition of PPAR-γ by GW9662 restored LPS-induced microglial activation and depressive-like behaviours in microglial FOXO3a-deficient mice. FOXO3a/PPAR-γ axis plays an important role in microglial activation and depression, identifying a new therapeutic avenue for the treatment of major depression.

Prostaglandin E2 inhibits the differentiation of T regulatory cells by Peroxisome Proliferator-Activated Receptor-Gamma during allergic rhinitis.

Allergic rhinitis (AR) represents a significant global health concern that can give rise to numerous diseases and result in labor productivity. T regulatory (Treg) cells are pivotal players in the pathogenesis of AR, and their deficiencies are closely related to Prostaglandin E2 (PGE2). However, the downstream mechanisms of this relationship remain poorly understood. This study aims to investigate the inhibitory mechanisms through which PGE2 impacts the differentiation of Treg cells. We compared the differentiation of Treg cells from naïve CD4+ T cells of AR patients and healthy controls, with or without the presence of PGE2 by flow cytometry. Intracellular cAMP concentration, mRNA and protein levels of cyclic-AMP dependent protein kinase A (PKA), as well as their downstream target, Peroxisome Proliferator-Activated Receptor-γ (PPAR-γ) were examined in Treg cells from AR and healthy donors. AR mouse model was established by pollen administration. PGE2 suppressed the differentiation of Treg cells from human naïve CD4+ T cells through the EP4 receptor. Furthermore, in AR patients and AR mouse, the expression of EP4 receptor were observed enhanced. The PGE2-EP4 signal was carried out by activating cAMP-PKA signaling pathway. Subsequently, phospholated PKA would suppress PPAR-γ expression. Treatment of Pioglitazone, a PPAR-γ agonist, was demonstrated to rescue the differentiation of Treg and help alleviate inflammation in the AR mouse model. In AR disease, the PGE2-EP4 signaling exerts an inhibitory effect on Treg differentiation by influencing the cAMP-PKA pathway and its downstream target PPAR-γ.

Anti-depressant effect of Naringenin-loaded hybridized nanoparticles in diabetic rats via PPARγ/NLRP3 pathway

Naringenin (NAR) has various biological activities but low bioavailability. The current study examines the effect of Naringenin-loaded hybridized nanoparticles (NAR-HNPs) and NAR on depression induced by streptozotocin (STZ) in rats. NAR-HNPs formula with the highest in vitro NAR released profile, lowest polydispersity index value (0.21 ± 0.02), highest entrapment efficiency (98.7 ± 2.01%), as well as an acceptable particle size and zeta potential of 415.2 ± 9.54 nm and 52.8 ± 1.04 mV, respectively, was considered the optimum formulation. It was characterized by differential scanning calorimetry, examined using a transmission electron microscope, and a stability study was conducted at different temperatures to monitor its stability efficiency showing that NAR-HNP formulation maintains stability at 4 °C. The selected formulation was subjected to an acute toxicological test, a pharmacokinetic analysis, and a Diabetes mellitus (DM) experimental model. STZ (50 mg/kg) given as a single i.p. rendered rats diabetic. Diabetic rat groups were allocated into 4 groups: one group received no treatment, while the remaining three received oral doses of unloaded HNPs, NAR (50 mg/kg), NAR-HNPs (50 mg/kg) and NAR (50 mg/kg) + peroxisome proliferator-activated receptor-γ (PPAR-γ) antagonist, GW9662 (1mg/kg, i.p.) for three weeks. Additional four non-diabetic rat groups received: distilled water (normal), free NAR, and NAR-HNPs, respectively for three weeks. NAR and NAR-HNPs reduced immobility time in forced swimming test and serum blood glucose while increasing serum insulin level. They also reduced cortical and hippocampal 5-hydroxyindoeacetic acid, 3,4-Dihydroxy-phenylacetic acid, malondialdehyde, NLR family pyrin domain containing-3 (NLRP3) and interleukin-1beta content while raised serotonin, nor-epinephrine, dopamine and glutathione level. PPAR-γ gene expression was elevated too. So, NAR and NAR-HNPs reduced DM-induced depression by influencing brain neurotransmitters and exhibiting anti-oxidant and anti-inflammatory effects through the activation PPAR-γ/ NLRP3 pathway. NAR-HNPs showed the best pharmacokinetic and therapeutic results.

Antihyperlipidemic activity of myricetin

AbstractMyricetin has been reported to have a wide variety of beneficial physiological functions. The present study investigated the antihyperlipidaemic activity of myricetin against hyperlipidaemia of high-fat diet-fed obese rats. The four-week antihyperlipidaemic activity was assayed by giving different doses of myricetin to hyperlipidaemic rats. Results showed that myricetin could reduce the harm caused by oxidative stress, decrease thiobarbituric acid reactive substances value, and decrease total cholesterol and triacylglycerol levels of hyperlipidaemic rats. Quantitative analysis of gene expression showed that myricetin's lipid-lowering activity can be activated by downregulating gene expression of fatty acid synthase (FAS) and peroxisome proliferator-activated receptor-γ (PPARγ) with upregulation of hormone-sensitive lipase (HSL) mRNA level. Thus, myricetin had significant health benefits and could be explored as a potentially promising dietary supplement for treating hyperlipidaemia.

Recent advances in understanding the molecular basis of infantile haemangioma development.

Infantile haemangioma (IH) - the most common vascular tumour of infancy - is comprised of diverse cell types, including endothelial cells, pericytes, fibroblasts and immune cells. IH is characterized by rapid proliferation followed by slow involution over 1-10 years. Most lesions regress spontaneously, but up to 10% can be disfiguring, with complications that require further medical treatment. Recent research has revealed the biological characteristics of IH, highlighting the involvement of angiogenesis and vasculogenesis during tumour formation. Gene expression profiling has provided vital insights into the underlying biological processes, with some of the key IH-related pathways identified, including vascular endothelial growth factor, the renin-angiotensin-aldosterone system, hypoxia-inducible factor 1α, Notch, platelet-derived growth factor, phosphoinositide 3-kinase/Akt/mammalian target of rapamycin, Janus kinase/signal transducers and activators of transcription, fibroblast growth factor, peroxisome proliferator-activated receptor-γ and insulin-like growth factor. Further evidence suggests extracellular matrix factors and hormone receptors regulate IH progression. In this review, we explore the molecular mechanisms involved in the proliferating, plateau and involuting phases of IH, identifying differentially expressed genes, targeted proteins and key signalling pathways. This knowledge will increase the broader understanding of vascular development, tissue remodelling and angiogenesis.

Regulation of PPARγ2 Stability and Activity by SHP-1.

The protein tyrosine phosphatase Src homology region 2 domain-containing phosphatase-1 (SHP-1) plays an important role in modulating glucose and lipid homeostasis. We previously suggested a potential role of SHP-1 in the regulation of peroxisome proliferator-activated receptor γ2 (PPARγ2) expression and activity but the mechanisms were unexplored. PPARγ2 is the master regulator of adipogenesis, but how its activity is regulated by tyrosine phosphorylation is largely unknown. Here, we found that SHP-1 binds to PPARγ2 primarily via its N-terminal SH2-domain. We confirmed the phosphorylation of PPARγ2 on tyrosine-residue 78 (Y78), which was reduced by SHP-1 invitro resulting in decreased PPARγ2 stability. Loss of SHP-1 led to elevated, agonist-induced expression of the classical PPARγ2 targets FABP4 and CD36, concomitant with increased lipid content in cells expressing PPARγ2, an effect blunted by abrogation of PPARγ2 phosphorylation. Collectively, we discovered that SHP-1 affects the stability of PPARγ2 through dephosphorylation thereby influencing adipogenesis.

Discovery of New Dual-Target Agents Against PPAR-γ and α-Glucosidase Enzymes with Molecular Modeling Methods: Molecular Docking, Molecular Dynamic Simulations, and MM/PBSA Analysis.

Type 2 diabetes mellitus (T2DM) has become a serious public health problem both in our country and worldwide, being the most prevalent type of diabetes. The combined use of drugs in the treatment of T2DM leads to serious side effects, including gastrointestinal problems, liver toxicity, hypoglycemia, and treatment costs. Hence, there has been a growing emphasis on drugs that demonstrate dual interactions. Several studies have suggested that dual-target agents for peroxisome proliferator-activated receptor-γ (PPAR-γ) and alpha-glucosidase (α-glucosidase) could be a potent approach for treating patients with diabetes. We aim to develop new antidiabetic agents that target PPAR-γ and α-glucosidase enzymes using molecular modeling techniques. These compounds show dual interactions, are more effective, and have fewer side effects. The molecular docking method was employed to investigate the enzyme-ligand interaction mechanisms of 159 newly designed compounds with target enzymes. Additionally, we evaluated the ADME properties and pharmacokinetic suitability of these compounds based on Lipinski and Veber's rules. Compound 70, which exhibited favorable ADME properties, demonstrated more effective binding energy with both PPAR-γ and α-glucosidase enzymes (-12,16kcal/mol, -10.07kcal/mol) compared to the reference compounds of Acetohexamide (-9.31kcal/mol, -7.48kcal/mol) and Glibenclamide (-11.12kcal/mol, -8.66kcal/mol). Further, analyses of MM/PBSA binding free energy and molecular dynamics (MD) simulations were conducted for target enzymes with compound 70, which exhibited the most favorable binding affinities with both enzymes. Based on this information, our study aims to contribute to the development of new dual-target antidiabetic agents with improved efficacy, reduced side effects, and enhanced reliability for diabetes treatment.

Pioglitazone Alleviates β1-Adrenergic Receptor Antibody-Induced Atrial Fibrillation Susceptivity via Mitigation of PPAR-γ-Mediated Metabolic Inflexibility.

Beta-1-adrenergic receptor antibodies (β1-AAbs) function as arrhythmogenic molecules in autoimmune-related atrial fibrillation (AF). This study examined the potential impact of pioglitazone, an agonist for peroxisome proliferator-activated receptor-γ (PPAR-γ), on atrial remodeling induced by β1-AAbs. An in vivo study was performed to confirm the protective effects of pioglitazone on β1- AAbs-induced atrial remodeling. GW9662, a PPAR-γ antagonist, was employed to identify the potential therapeutic target of pioglitazone. The rats were administered subcutaneous injections of the second extracellular loop peptide for 8 weeks to establish active immunization models. Pioglitazone was then administered orally for 2 weeks. Epicardial electrophysiologic studies, multielectrode array measurements, and echocardiography were conducted to examine atrial remodeling. Glucose metabolism products and key metabolic molecules were measured to evaluate the atrial substrate metabolism. Mitochondrial morphologies and function indices were tested to depict the underlying links between atrial metabolism and mitochondrial homeostasis under the pioglitazone treatment. Pioglitazone significantly reversed β1-AAbs-induced AF susceptibility, ameliorated atrial structural remodeling, decreased the global insulin resistance reflected in the plasma glucose and insulin levels, and increased the protein expressions of glycolipid uptake and transportation (GLUT1, CD36, and CPT1a). These trends were counterbalanced by the GW9662 intervention. Mechanistically, pioglitazone mitigated the atrial mitochondrial network damage and partly renovated the mitochondrial biogenesis, even the mitochondrial dynamics, which were reversed by inhibiting the PPAR-γ target. Pioglitazone effectively reduced the AF vulnerability and recovered the atrial myocardial metabolism and mitochondrial damage. The potential anti-remodeling effect of pioglitazone on the atrium was associated with the moderately increased expression of key membrane proteins related to glucose transporter and fatty acid uptake, which may promote the increased myocardial preference for utilization of FA as the key cardiac oxidative fuel and ameliorate the atrial metabolic inflexibility.

Norisoboldine, a Natural Alkaloid from Lindera aggregata (Sims) Kosterm, Promotes Osteogenic Differentiation via S6K1 Signaling Pathway and Prevents Bone Loss in OVX Mice.

Norisoboldine (NOR) is a major isoquinoline alkaloid component in the traditional Chinese herbal plant Lindera aggregata (Sims) Kosterm, with previously reported anti-osteoclast differentiation and antiarthritis properties. However, the roles of NOR on osteoblasts, bone marrow mesenchymal stem cells (BMSCs), and osteoporosis in vivo have never been well established. This study investigates the ability of NOR to improve bone formation in vitro and in vivo. Osteoblasts and BMSCs are used to study the effect of NOR on osteogenic and adipogenic differentiation. It finds that NOR promotes osteogenic differentiation of osteoblasts and BMSCs, while inhibiting adipogenic differentiation of BMSCs by reducing the relative expression of peroxisome proliferator-activated receptorγ (Ppar-γ) and adiponectin, C1Q and collagen domain containing (Adipoq). Mechanistic studies show that NOR increases osteoblast differentiation through the mechanistic target of rapamycin kinase (mTOR)/ribosomal protein S6 kinase; polypeptide 1 (S6K1) pathway, and treatment with an mTOR inhibitor rapamycin blocked the NOR-induced increase in mineral accumulation. Finally, the study evaluates the therapeutic potential of NOR in a mouse model of ovariectomy (OVX)-induced bone loss. NOR prevents bone loss in both trabecular and cortical bone by increasing osteoblast number and phospho-S6K1 (p-S6K1) expression in osteoblasts. NOR effects in enhancing osteoblast-induced bone formation via S6K1 pathway, suggesting the potential of NOR in osteoporosis treatment by increasing bone formation.

Dipeptidyl peptidase-4 disturbs adipocyte differentiation via the negative regulation of the glucagon-like peptide-1/adiponectin-cathepsin K axis in mice under chronic stress conditions.

Exposure to chronic psychosocial stress is a risk factor for metabolic disorders. Because dipeptidyl peptidase-4 (DPP4) and cysteinyl cathepsin K (CTSK) play important roles in human pathobiology, we investigated the role(s) of DPP4 in stress-related adipocyte differentiation, with a focus on the glucagon-like peptide-1 (GLP-1)/adiponectin-CTSK axis invivo and invitro. Plasma and inguinal adipose tissue from non-stress wild-type (DPP4+/+), DPP4-knockout (DPP4-/-) and CTSK-knockout (CTSK-/-) mice, and stressed DPP4+/+, DPP4-/-, CTSK-/-, and DPP4+/+ mice underwent stress exposure plus GLP-1 receptor agonist exenatide loading for 2 weeks and then were analyzed for stress-related biological and/or morphological alterations. On day 14 under chronic stress, stress decreased the weights of adipose tissue and resulted in harmful changes in the plasma levels of DPP4, GLP-1, CTSK, adiponectin, and tumor necrosis factor-α proteins and the adipose tissue levels of CTSK, preadipocyte factor-1, fatty acid binding protein-4, CCAAT/enhancer binding protein-α, GLP-1 receptor, peroxisome proliferator-activated receptor-γ, perilipin2, secreted frizzled-related protein-4, Wnt5α, Wnt11 and β-catenin proteins and/or mRNAs as well as macrophage infiltration in adipose tissue; these changes were rectified by DPP4 deletion. GLP-1 receptor activation and CTSK deletion mimic the adipose benefits of DPP4 deficiency. Invitro, CTSK silencing and overexpression respectively prevented and facilitated stress serum and oxidative stress-induced adipocyte differentiation accompanied with changes in the levels of pref-1, C/EBP-α, and PPAR-γ in 3T3-L1 cells. Thus, these findings indicated that increased DPP4 plays an essential role in stress-related adipocyte differentiation, possibly through a negative regulation of GLP-1/adiponectin-CTSK axis activation in mice under chronic stress conditions.

Moringin alleviates DSS-induced ulcerative colitis in mice by regulating Nrf2/NF-κB pathway and PI3K/AKT/mTOR pathway

Ulcerative colitis (UC) is a main form of inflammatory bowel disease (IBD), which is a chronic and immune-mediated inflammatory disease. Moringin (MOR) is an isothiocyanate isolated from Moringa oleifera Lam., and has been recognized as a promising potent drug for inflammatory diseases and antibacterial infections. The present study investigated the role of moringin in dextran sulfate sodium (DSS)-induced UC mice. Mouse colitis was induced by adding DSS to the drinking water for seven consecutive days. Our experimental results showed that MOR relieves DSS-induced UC in mice by increasing body weight and colonic length, and reducing the disease activity index and histological injury. Mechanistically, MOR improves intestinal barrier function by increasing the expression of tight junction proteins (TJPs) and enhancing the secretion of mucin in DSS-induced mice. MOR inhibits inflammatory response and intestinal damage by regulating Nrf2/NF-κB signaling pathway and modulating the PI3K/AKT/mTOR pathway. Furthermore, in Nrf2 knockout (Nrf2-/-) mice, the protective effects of MOR on DSS-induced UC were abolished. Meanwhile, treatment with MOR reduced inflammation and cell damage via regulating Nrf2/NF-κB pathway in a lipopolysaccharide (LPS)-induced inflammation model of Caco-2 cells. In contrast, ML385, an Nrf2 inhibitor, might eliminate the protection provided by MOR. Notably, treatment with MOR significantly up-regulated the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ), suggesting that MOR may be a potential PPAR-γ activator. In conclusion, MOR exerts protective effect in UC by improving intestinal barrier function, regulating Nrf2/NF-κB and PI3K/AKT/mTOR signaling pathways, and another effect associated with the regulation of PPAR-γ expression.