Pioglitazone-induced alterations of purine metabolism in healthy male subjects.

Pioglitazone is class of thiazolidinediones that activates peroxisome proliferator-activated receptors (PPARs) in adipocytes to improve glucose metabolism and insulin sensitivity and has been used as a treatment for type 2 diabetes. However, the underlying mechanisms of associated pioglitazone-induced effects remain unclear. Our study aimed to investigate endogenous metabolite alterations associated with pioglitazone administration in healthy male subjects using an untargeted metabolomics approach. All subjects received 30 mg of pioglitazone once daily in the assigned sequence and period. Urine samples were collected before pioglitazone administration and for 24 h after 7 days of administration. A total of 1465 compounds were detected and filtered using a coefficient of variance below 30% and 108 metabolites were significantly altered upon pioglitazone administration via multivariate statistical analysis. Fourteen significant metabolites were identified using authentic standards and public libraries. Additionally, pathway analysis revealed that metabolites from purine and beta-alanine metabolisms were significantly altered after pioglitazone administration. Further analysis of quantification of metabolites from purine metabolism, revealed that the xanthine/hypoxanthine and uric acid/xanthine ratios were significantly decreased at post-dose. Pioglitazone-dependent endogenous metabolites and metabolic ratio indicated the potential effect of pioglitazone on the activation of PPAR and fatty acid synthesis. Additional studies involving patients are required to validate these findings.

Synthesis, biological evaluation and molecular docking study of pyrimidine linked thiazolidinedione derivatives as potential antimicrobial and antitubercular agents.

The design and development of novel antimicrobial agents are highly desired to combat the emergence of medication resistance against microorganisms that cause infections. A series of new pyrimidine-linked thiazolidinedione derivatives (5a-j) were synthesized, characterized, and their antimicrobial properties assessed in the current investigation. Here, novel pyrimidine-linked thiazolidinedione compounds were designed using the molecular hybridization approach. Elemental and spectral techniques were used to determine the structures of the synthesized hybrids. The majority of compounds showed encouraging antibacterial properties. Among the active compounds, 5g, 5i, and 5j showed 1.85, 1.15, and 1.38 times the activity of streptomycin against S. aureus, respectively, with MIC values of 6.4, 10.3, and 8.6 µM. With MIC values of 10.8, 21.9, and 15.4 µM, respectively, the compounds 5g, 5i, and 5j showed 2.14, 1.05, and 1.50 times the activity of linezolid against the methicillin-resistant S. aureus (MRSA) strain. Furthermore, when compared to the reference medications, compounds 5g, 5i, and 5j demonstrated broad-range antimicrobial efficacy against all tested strains of bacteria and fungus. Out of all the compounds that were investigated, compounds 5g, 5i, and 5j showed noteworthy anti-tubercular activity. 5g is the most effective, 1.59 times more effective than reference drug isoniazid. To anticipate the binding manner, the synthesized potent compounds were subjected to molecular docking into the active binding site of MRSA and the mycobacterial membrane protein large 3 (MmpL3) protein. The compounds 5g, 5i, and 5j may eventually serve as lead compounds in the search for antimicrobial and anti-TB therapeutic agents.

New thiazolidine-2,4-diones as potential anticancer agents and apoptotic inducers targeting VEGFR-2 kinase: Design, synthesis, in silico and in vitro studies.

BACKGROUND: VEGFR-2 has emerged as a prominent positive regulator of cancer progression. AIM: Discovery of new anticancer agents and apoptotic inducers targeting VEGFR-2. METHODS: Design and synthesis of new thiazolidine-2,4-diones followed by extensive in vitro studies, including VEGFR-2 inhibition assay, MTT assay, apoptosis analysis, and cell migration assay. In silico investigations including docking, MD simulations, ADMET, toxicity, and DFT studies were performed. RESULTS: Compound 15 showed the strongest VEGFR-2 inhibitory activity with an IC50 value of 0.066 µM. Additionally, most of the synthesized compounds showed anti-proliferative activity against HepG2 and MCF-7 cancer cell lines at the micromolar range with IC50 values ranging from 0.04 to 4.71 µM, relative to sorafenib (IC50 = 2.24 ± 0.06 and 3.17 ± 0.01 µM against HepG2 and MCF-7, respectively). Also, compound 15 showed selectivity indices of 1.36 and 2.08 against HepG2 and MCF-7, respectively. Furthermore, compound 15 showed a significant apoptotic effect and arrested the cell cycle of MCF-7 cells at the S phase. Moreover, compound 15 had a significant inhibitory effect on the ability of MCF-7 cells to heal from. Docking studies revealed that the synthesized thiazolidine-2,4-diones have a binding pattern approaching sorafenib. MD simulations indicated the stability of compound 15 in the active pocket of VEGFR-2 for 200 ns. ADMET and toxicity studies indicated an acceptable pharmacokinetic profile. DFT studies confirmed the ability of compound 15 to interact with VEGFR-2. CONCLUSION: Compound 15 has promising anticancer activity targeting VEGFR-2 with significant activity as an apoptosis inducer.

Thiazolidinedione enhances the efficacy of anti-PD-1 monoclonal antibody in murine melanoma.

Several clinical studies observed a surprising beneficial effect of obesity on enhancing immunotherapy responsiveness in patients with melanoma, highlighting an as-yet insufficiently understood relationship between metabolism and immunogenicity. Here, we demonstrate that the thiazolidinedione (TZD) rosiglitazone, a drug commonly used to treat diabetes by sequestering fatty acids in metabolically inert subcutaneous adipose tissue, improved sensitivity to anti-programmed cell death protein 1 (PD-1) treatment in YUMMER1.7 tumor-bearing mice, an initially immunotherapy-sensitive murine melanoma model. We observed a transition from high to intermediate PD-1 expression in tumor-infiltrating CD8+ T cells. Moreover, TZD inhibited PD-1 expression in mouse and human T cells treated in vitro. In addition to its direct impact on immune cells, TZD also decreased circulating insulin concentrations, while insulin induced T cell exhaustion in culture. In TZD-treated mice, we observed higher fatty acid concentrations in the tumor microenvironment, with fatty acids protecting against exhaustion in culture. Together, these data are consistent with an indirect mechanism of TZD inhibiting T cell exhaustion. Finally, we analyzed imaging data from patients with melanoma before and after anti-PD-1 treatment, confirming the beneficial effect of increased subcutaneous fat on anti-PD-1 responsiveness in patients. We also found that the expression of peroxisome proliferator-activated receptor gamma (PPARγ), the canonical activator of lipid uptake and adipogenesis activated by TZD, correlated with overall survival time. Taken together, these data identify a new adjuvant to enhance immunotherapy efficacy in YUMMER1.7 melanoma mice, and discover a new metabolism-based prognostic marker in human melanoma.NEW & NOTEWORTHY Zhang et al. demonstrate that the diabetes drug rosiglitazone improves the efficacy of immunotherapy in mouse melanoma. This effect is both direct and indirect: TZD directly reduces PD-1 expression in CD8+ T cells (i.e., reduces exhaustion), and indirectly reduces exhaustion by lowering insulin levels and increasing local fat. Finally, they demonstrate that hallmarks of TZD action (such as PPARγ expression and subcutaneous fat content) correlate with improved immunotherapy efficacy in humans with melanoma.

Peroxisome proliferator activated receptor-gamma (PPAR-γ) ligand, pioglitazone, increases analgesic and anti-inflammatory effects of naproxen.

The aim of this study was the investigation of analgesic and anti-inflammatory activity of naproxen and pioglitazone following intra-plantar injection of carrageenan and assessment of the PPAR-γ receptor involvement in these effects. Rats were intra-plantarly injected with carrageenan (1%, 100 µl) to induce thermal hyperalgesia and paw inflammation. Different groups of rats were pre-treated intraperitoneally with naproxen (1 and 10 mg/kg) or pioglitazone (3 and 10 mg/kg) or GW9662 (a selective PPAR-γ antagonist, 100 µl/paw). The volume of the paw was evaluated using a plethysmometer, and the hot plate test was employed to assess the pain threshold in the animals. Finally, TNF-α, IL-1ß, IL-6, and myeloperoxidase (MPO) activity status were evaluated in the hind paw tissue. Naproxen and pioglitazone demonstrated analgesic and anti-inflammatory activity. Concurrent injection of an ineffective dose of naproxen (1 mg/kg) with an ineffective dose of pioglitazone (3 mg/kg) caused augmented analgesic and anti-inflammatory activity, significantly (p≤0.001 and p≤0.01, respectively). Additionally, intra-plantar injection of GW-9662 before naproxen or pioglitazone significantly suppressed their analgesic (p≤0.001) and anti-inflammatory activity (p≤0.01). Also, naproxen and pioglitazone (10 mg/kg) significantly (p≤0.001) reduced carrageenan-induced MPO activity and TNF-α, IL-6, and IL-1ß releasing. Furthermore, PPAR-γ blockade significantly prevented suppressive effects of naproxen and pioglitazone on the MPO activity and inflammatory cytokines. Pioglitazone significantly increased analgesic and anti-inflammatory effects of naproxen. This study proposes that concurrent treatment with naproxen and pioglitazone may be a substitute for overcome pain and inflammation clinically, in the future, particularly in patients with cardiovascular disorders and diabetes.

An amalgamated molecular dynamic and Gaussian based 3D-QSAR study for the design of 2,4-thiazolidinediones as potential PTP1B inhibitors.

Overexpression of protein tyrosine phosphatase 1B (PTP1B) is the major cause of various diseases such as diabetes, obesity, and cancer. PTP1B has been identified as a negative regulator of the insulin signaling cascade, thereby causing diabetes. Numerous anti-diabetic medications based on thiazolidinedione have been successfully developed; however, 2,4-thiazolidinedione (2,4-TZD) scaffolds have been reported as potential PTP1B inhibitors for the manifestation of type 2 diabetes mellitus involving insulin resistance. In the present study, we have employed amalgamated approach involving MD-simulation studies (100 ns) as well as Gaussian field-based 3D-QSAR to develop a pharmacophoric model of 2,4-TZD as potent PTP1B inhibitors. MD simulation studies of the most potent compound in the PTP1B (PDB Id: 2QBS) binding pocket revealed that compound 43 was stable in the binding pocket and demonstrated excellent binding efficacy within the active site pocket. MM/GBSA results revealed that compound 43, bearing C-5 arylidine substitution, strongly bound to the target as compared to rosiglitazone with ΔGMM/GBSA difference of -11.13 kcal/mol. PCA, Rg, RMSF, RMSD, and SASA were analyzed from the complex's trajectories to anticipate the simulation outcome. We have suggested a series of 2,4-TZD as possible PTP1B inhibitors based on the results of MD simulation and 3D-QSAR studies.

The effect of thiazolidinediones on body fat redistribution in adults: A systematic review and meta-analysis of randomized controlled trials.

Visceral adiposity is a strong predictor of cardiometabolic risk. Thiazolidinediones (TZDs) are associated with a shift in fat redistribution from visceral adipose tissue (VAT) to subcutaneous adipose tissue (SAT). We aimed to compare the effects of TZD and other interventions on fat remodeling in adults in randomized controlled trials. Among the 1331 retrieved studies, 39 trials with 1765 participants were included in the meta-analysis. The standardized mean difference in VAT change was not significantly different between TZD and comparators across the overall studies. Intriguingly, TZD treatment resulted in significant decreases in VAT compared with placebo and sulfonylureas (p < 0.05), although recombinant human growth hormone was superior to TZD regarding VAT reduction (p < 0.05). Data from 216 participants showed TZD leading to a greater reduction in liver fat percentage than comparators (p < 0.05). Compared with the controls, TZD significantly increased SAT, total body fat, weight, waist circumference, and body mass index (p < 0.05). However, TZD pronouncedly improved glucose control, insulin resistance, adiponectin, and lipid profile (p < 0.05). TZD provides a favorable effect on fat redistribution and benefits insulin sensitivity, suggesting a potentially valuable approach in cardiometabolic risk management.

Combined In Silico and In Vitro Analyses to Assess the Anticancer Potential of Thiazolidinedione-Thiosemicarbazone Hybrid Molecules.

The number of people affected by cancer and antibiotic-resistant bacterial infections has increased, such that both diseases are already seen as current and future leading causes of death globally. To address this issue, based on a combined in silico and in vitro approach, we explored the anticancer potential of known antibacterials with a thiazolidinedione-thiosemicarbazone (TZD-TSC) core structure. A cytotoxicity assessment showed encouraging results for compounds 2-4, with IC50 values against T98G and HepG2 cells in the low micromolar range. TZD-TSC 3 proved to be most toxic to cancer cell lines, with IC50 values of 2.97 ± 0.39 µM against human hepatoma HepG2 cells and IC50 values of 28.34 ± 2.21 µM against human glioblastoma T98G cells. Additionally, compound 3 induced apoptosis and showed no specific hemolytic activity. Furthermore, treatment using 3 on cancer cell lines alters these cells' morphology and further suppresses migratory activity. Molecular docking, in turn, suggests that 3 would have the capacity to simultaneously target HDACs and PPARγ, by the activation of PPARγ and the inhibition of both HDAC4 and HDAC8. Thus, the promising preliminary results obtained with TZD-TSC 3 represent an encouraging starting point for the rational design of novel chemotherapeutics with dual antibacterial and anticancer activities.

Insulin in combination with pioglitazone prevents advanced cachexia in 256-Walker tumor-bearing rats: effect is greater than treatment alone and is associated with improved insulin sensitivity.

BACKGROUND: Insulin (INS) resistance and hypoinsulinemia commonly observed in cancer-carrying, can contribute to cachexia. However, the effects of INS and INS sensitizers, such as pioglitazone (PIO), particularly when used in combination therapy, on cancer cachexia have not been evaluated sufficiently. We investigated the effects of INS and PIO, at various doses, either isolated or combined, on cachexia in Walker-256 tumor-bearing rats (TB rats). METHODS: INS or INS + PIO were administered in TB rats, for 6 or 12 days, starting from the day of tumor cells inoculation. RESULTS: INS at 18 or 27 U/kg (12-days treatment), but not 9 U/kg, reduced fat loss and slightly prevented weight loss. However, INS 18 U/kg + PIO 5, 10, 20, or 40 mg/kg (6 or 12-day treatment) reduced fat loss and markedly prevented weight loss but did not affect muscle wasting. While TB rats lost weight (37.9% in 12 days), TB rats treated with INS 18 U/kg + PIO 5 mg/kg showed pronounced weight gain (73.7%), which was greater than the sum (synergism) of the weight gains promoted by isolated treatments with INS 18 U/kg (14.7%) or PIO 5 mg/kg (13.1%). The beneficial effect of the INS 18 U/kg + PIO 5 mg/kg on weight loss was associated with improved INS sensitivity, as indicated by the higher blood glucose clearance constant (kITT), decreased levels of free fatty acids and triacylglycerols (INS resistance-inducing factors) in the blood, and increased expression of p-Akt (INS signaling pathway protein) in adipose tissue. CONCLUSIONS: The combined treatment with INS 18 U/kg + PIO 5 mg/kg was more effective in preventing advanced cachexia in TB rats than each treatment alone, emerging as the best approach, considering the lower dosage and higher efficacy. This combination completely preserved adipose mass and markedly reduced weight loss through a synergistic mechanism linked to improved insulin sensitivity. These findings provide new insights into the importance of drug combinations in effectively combating fat loss in advanced cachexia.

Design, synthesis and biological evaluation of novel 2,4-thiazolidinedione derivatives able to target the human BAG3 protein.

The Bcl-2-associated athanogene 3 (BAG3) protein plays multiple roles in controlling cellular homeostasis, and it has been reported to be deregulated in many cancers, leading tumor cell apoptosis escape. BAG3 protein is then an emerging target for its oncogenic activities in both leukemia and solid cancers, such as medulloblastoma. In this work a series of forty-four compounds were designed and successfully synthesized by the modification and optimization of a previously reported 2,4-thiazolidinedione derivative 28. Using an efficient cloning and transfection in human embryonic kidney HEK-293T cells, BAG3 was collected and purified by chromatographic techniques such as IMAC and SEC, respectively. Subsequently, through Surface Plasmon Resonance (SPR) all the compounds were evaluated for their binding ability to BAG3, highlighting the compound FB49 as the one having the greatest affinity for the protein (Kd = 45 ± 6 µM) also against the reference compound 28. Further analysis carried out by Saturation Transfer Difference (STD) Nuclear Magnetic Resonance (NMR) spectroscopy further confirmed the highest affinity of FB49 for the protein. In vitro biological investigation showed that compound FB49 is endowed with an antiproliferative activity in the micromolar range in three human tumoral cell lines and more importantly is devoid of toxicity in human peripheral mononuclear cell deriving from healthy donors. Moreover, FB49 was able to block cell cycle in G1 phase and to induce apoptosis as well as autophagy in medulloblastoma HD-MB03 treated cells. In addition, FB49 demonstrated a synergistic effect when combined with a chemotherapy cocktail of Vincristine, Etoposide, Cisplatin, Cyclophosphamide (VECC). In conclusion we have demonstrated that FB49 is a new derivative able to bind human BAG3 with high affinity and could be used as BAG3 modulator in cancers correlated with overexpression of this protein.

Peroxisome proliferator-activated receptor gamma agonist pioglitazone alleviates hemorrhage-induced thalamic pain and neuroinflammation.

BACKGROUND: Thalamic pain frequently occurs after stroke and is a challenging clinical issue. However, the mechanisms underlying thalamic pain remain unclear. Neuroinflammation is a key determining factor in the occurrence and maintenance of hemorrhage-induced thalamic pain. Pioglitazone is an agonist of peroxisome proliferator-activated receptor gamma (PPARγ) and shows anti-inflammatory effects in multiple diseases. The present work focused on exploring whether PPARγ is related to hemorrhage-induced thalamic pain. METHODS: Immunostaining was conducted to analyze the cellular localization of PPARγ and co-localization was evaluated with NeuN, ionized calcium-binding adapter molecular 1 (IBA1), and glia fibrillary acidic protein (GFAP). Western blot analyses were used to evaluate MyD88, pNF-κB/NF-κB, pSTAT6/STAT6, IL-1ß, TNF-α, iNOS, Arg-1, IL-4, IL-6, and IL-10 expression. Behavioral tests in mice were conducted to evaluate continuous pain hypersensitivity. RESULTS: We found that pioglitazone appeared to mitigate the contralateral hemorrhage-induced thalamic pain while inhibiting inflammatory responses. Additionally, Pioglitazone induced phosphorylation of STAT6 and suppressed the phosphorylation NF-κB in our model of thalamic pain. These effects could be partially reversed with the PPARγ antagonist GW9662. CONCLUSION: The PPARγ agonist pioglitazone can mitigate mechanical allodynia by suppressing the NF-κB inflammasome while activating the STAT6 signal pathway, which are well-known to be associated with inflammation.

Unveiling clinically significant PPARγ mutations for thiazolidinedione treatment responsiveness through atomistic simulations.

In Type 2 diabetes, increased insulin sensitivity is induced by thiazolidinedione activation of the peroxisome proliferator-activated receptor gamma (PPARγ). Recent data indicate a relationship between SNPs in PPARγ and poor drug response. Therefore, understanding the pathogenic consequences of mutations in PPARγ-mediated protein-drug interactions will be prima-facie for establishing personalized medicine. The PPARG gene has 197 missense SNPs, 22 of which were determined to be both deleterious and destabilizing, employing in silico approaches. Molecular docking analysis suggested that the mutation influenced the binding energy of at least seven of the variants. The mutant R316H was identified as the most damaging and deleterious from the observed results. For a better understanding of the dynamic variation upon mutation at the atomic level, molecular dynamics simulations of the wild-type and R316H mutant PPARγ structure were performed. The analysis indicates that the mutation increased protein structural compactness while decreasing flexibility. The reduced dynamics in the mutant structure was further validated by principal component analysis. This mechanistic evaluation of the PPARγ protein variants provides insight into the relationship between genetic variation and interindividual variability of drug responsiveness and will facilitate the future studies for the development of tailored treatment regime for precision medicine.

Lobeglitazone inhibits LPS-induced NLRP3 inflammasome activation and inflammation in the liver.

Liver inflammation is a common feature of chronic liver disease and is often associated with increased exposure of the liver to lipopolysaccharide (LPS). Kupffer cells (KCs) are macrophages in the liver and produce various cytokines. Activation of KCs through the NLRP3 inflammasome pathway leads to release of proinflammatory cytokines and induces hepatocyte injury and hepatic stellate cell (HSC) activation. Lobeglitazone is a peroxisome proliferator-activated receptor gamma ligand and a type of thiazolidinedione that elicits anti-inflammatory effects. However, there is no clear evidence that it has direct anti-inflammatory effects in the liver. This study showed that lobeglitazone reduces LPS-induced NLPR3 inflammasome activation and production of proinflammatory cytokines in primary KCs and hepatocytes. Cytokines secreted by activated KCs increased hepatocyte inflammation and HSC activation, and lobeglitazone inhibited these responses. In addition, lobeglitazone suppressed liver fibrosis by inhibiting LPS-induced transforming growth factor (TGF)-ß secretion and TGF-ß-induced CTGF expression. The inhibitory effect of lobeglitazone on inflammasome activation was associated with suppression of liver fibrosis. These results suggest that lobeglitazone may be a treatment option for inflammation and fibrosis in the liver.

PPARγ agonist inhibits c-Myc-mediated colorectal cancer tumor immune escape.

As a master transcription factor, c-Myc plays an important role in promoting tumor immune escape. In addition, PPARγ (peroxisome proliferator-activated receptor γ) regulates cell metabolism, inflammation, and tumor progression, while the effect of PPARγ on c-Myc-mediated tumor immune escape is still unclear. Here we found that cells treated with PPARγ agonist pioglitazone (PIOG) reduced c-Myc protein expression in a PPARγ-dependent manner. qPCR analysis showed that PIOG had no significant effect on c-Myc gene levels. Further analysis showed that PIOG decreased c-Myc protein half-life. Moreover, PIOG increased the binding of c-Myc to PPARγ, and induced c-Myc ubiquitination and degradation. Importantly, c-Myc increased PD-L1 and CD47 immune checkpoint protein expression and promoted tumor immune escape, while PIOG inhibited this event. These findings suggest that PPARγ agonist inhibited c-Myc-mediated tumor immune escape by inducing its ubiquitination and degradation.

The role of PPAR-γ in memory deficits induced by prenatal and lactation alcohol exposure in mice.

Patients diagnosed with fetal alcohol spectrum disorder (FASD) show persistent cognitive disabilities, including memory deficits. However, the neurobiological substrates underlying these deficits remain unclear. Here, we show that prenatal and lactation alcohol exposure (PLAE) in mice induces FASD-like memory impairments. This is accompanied by a reduction of N-acylethanolamines (NAEs) and peroxisome proliferator-activated receptor gamma (PPAR-γ) in the hippocampus specifically in a childhood-like period (at post-natal day (PD) 25). To determine their role in memory deficits, two pharmacological approaches were performed during this specific period of early life. Thus, memory performance was tested after the repeated administration (from PD25 to PD34) of: i) URB597, to increase NAEs, with GW9662, a PPAR-γ antagonist; ii) pioglitazone, a PPAR-γ agonist. We observed that URB597 suppresses PLAE-induced memory deficits through a PPAR-γ dependent mechanism, since its effects are prevented by GW9662. Direct PPAR-γ activation, using pioglitazone, also ameliorates memory impairments. Lastly, to further investigate the region and cellular specificity, we demonstrate that an early overexpression of PPAR-γ, by means of a viral vector, in hippocampal astrocytes mitigates memory deficits induced by PLAE. Together, our data reveal that disruptions of PPAR-γ signaling during neurodevelopment contribute to PLAE-induced memory dysfunction. In turn, PPAR-γ activation during a childhood-like period is a promising therapeutic approach for memory deficits in the context of early alcohol exposure. Thus, these findings contribute to the gaining insight into the mechanisms that might underlie memory impairments in FASD patients.

Anti-fibrotic effect of ciglitazone in HRV-induced airway remodelling cell model.

Fibrosis is an important phenomenon as it can occur early in the pathogenesis of asthma; it may be associated with disease severity and resistance to therapy. There is a strong evidence that infection caused by human rhinovirus (HRV) contributes to remodelling process, but there is lack of studies clearly explaining this pathway. Synthetic peroxisome proliferator-activated receptor (PPAR) γ presents immunomodulatory and anti-inflammatory features. In this study, we examined immunomodulatory properties of ciglitazone - PPAR-γ agonist, in development and modulation of airway remodelling. Epithelial cells (NHBE) and two lines of fibroblasts (WI-38, HFL1) were stimulated with ciglitazone and rhinovirus. The expression of genes related to airway remodelling process were analysed in the cells; moreover NF-κB, c-Myc and STAT3 were silenced in order to estimate potential pathways involved. Ciglitazone decreased mRNA expression of MMP-9 and TGF-ß. It also modified the expression of α-SMA and collagen after rhinovirus infection. Transcription factors knockdown altered the levels of expression. The results suggest possible anti-fibrotic activity of PPAR-γ agonist in human airway cells. Ciglitazone has been shown to be dependent on NF-κB- and STAT3-related pathways, thus, the PPAR-γ agonist may have therapeutic potential for the treatment of airway remodelling in asthma.

Investigation of the Antifungal and Anticancer Effects of the Novel Synthesized Thiazolidinedione by Ion-Conductance Microscopy.

In connection with the emergence of new pathogenic strains of Candida, the search for more effective antifungal drugs becomes a challenge. Part of the preclinical trials of such drugs can be carried out using the innovative ion-conductance microscopy (ICM) method, whose unique characteristics make it possible to study the biophysical characteristics of biological objects with high accuracy and low invasiveness. We conducted a study of a novel synthesized thiazolidinedione's antimicrobial (for Candida spp.) and anticancer properties (on samples of the human prostate cell line PC3), and its drug toxicity (on a sample of the human kidney cell line HEK293). We used a scanning ion-conductance microscope (SICM) to obtain the topography and mechanical properties of cells and an amperometric method using Pt-nanoelectrodes to register reactive oxygen species (ROS) expression. All data and results are obtained and presented for the first time.

Brown Adipose Tissue PPARγ Is Required for the Insulin-Sensitizing Action of Thiazolidinediones.

Brown adipose tissue (BAT) plays a critical role in metabolic homeostasis. BAT dysfunction is associated with the development of obesity through an imbalance between energy expenditure and energy intake. The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) is the master regulator of adipogenesis. However, the roles of PPARγ and thiazolidinediones (TZDs) in the regulation of BAT metabolism remain unclear. TZDs, which are selective PPARγ activators, improve systemic insulin resistance in animals and humans. In the present study, we generated brown adipocyte-specific PPARγ-deficient mice (BATγKO) to examine the in vivo roles of PPARγ and TZDs in BAT metabolism. In electron microscopic examinations, brown adipocyte-specific PPARγ deletion promoted severe whitening of brown fat and morphological alteration of mitochondria. Brown adipocyte-specific PPARγ deletion also reduced mRNA expression of BATselective genes. Although there was no difference in energy expenditure between control and BATγKO mice in calorimetry, norepinephrine-induced thermogenesis was impaired in BATγKO mice. Moreover, pioglitazone treatment improved diet-induced insulin resistance in the control mice but not in the BATγKO mice. These findings suggest that BAT PPARγ is necessary for the maintenance of brown adipocyte function and for the insulin-sensitizing action of TZDs.

The protective role of peroxisome proliferator-activated receptor gamma in lipotoxic podocytes.

Podocytes are specialized epithelial cells that maintain the glomerular filtration barrier. These cells are susceptible to lipotoxicity in the obese state and irreversibly lost during kidney disease leading to proteinuria and renal injury. PPARγ is a nuclear receptor whose activation can be renoprotective. This study examined the role of PPARγ in the lipotoxic podocyte using a PPARγ knockout (PPARγKO) cell line and since the activation of PPARγ by Thiazolidinediones (TZD) is limited by their side effects, it explored other alternative therapies to prevent podocyte lipotoxic damage. Wild-type and PPARγKO podocytes were exposed to the fatty acid palmitic acid (PA) and treated with the TZD (Pioglitazone) and/or the Retinoid X receptor (RXR) agonist Bexarotene (BX). It revealed that podocyte PPARγ is essential for podocyte function. PPARγ deletion reduced key podocyte proteins including podocin and nephrin while increasing basal levels of oxidative and ER stress causing apoptosis and cell death. A combination therapy of low-dose TZD and BX activated both the PPARγ and RXR receptors reducing PA-induced podocyte damage. This study confirms the crucial role of PPARγ in podocyte biology and that their activation in combination therapy of TZD and BX may be beneficial in the treatment of obesity-related kidney disease.

GIPR expression is induced by thiazolidinediones in a PPARγ-independent manner and repressed by obesogenic stimuli.

Adipose tissue (AT) dysfunctions are associated with the onset of insulin resistance (IR) and type 2 diabetes mellitus (T2DM). Targeting glucose-dependent insulinotropic peptide receptor (GIPR) is a valid option to increase the efficacy of glucagon-like peptide 1 (GLP-1) receptor agonists in T2DM treatment. Nevertheless, the therapeutic potential of targeting the GIP/GIPR axis and its effect on the AT are controversial. In this work, we explored the expression and regulation of GIPR in precursor cells and mature adipocytes, investigating if and how obesogenic stimuli and thiazolidinediones perturb GIPR expression. Using publicly available gene expression datasets, we assessed that, among white adipose tissue (WAT) cells, adipocytes express lower levels of GIPR compared to cells of mesothelial origin, pericytes, dendritic and NK/T cells. However, we report that GIPR levels markedly increase during the in vitro differentiation of both murine and human adipocytes, from 3T3-L1 and human mesenchymal precursor cells (MSCs), respectively. Notably, we demonstrated that thiazolidinediones - ie. synthetic PPARγ agonists widely used as anti-diabetic drugs and contained in the adipogenic mix - markedly induce GIPR expression. Moreover, using multiple in vitro systems, we assessed that thiazolidinediones induce GIPR in a PPARγ-independent manner. Our results support the hypothesis that PPARγ synthetic agonists may be used to increase GIPR levels in AT, potentially affecting in turn the targeting of GIP system in patients with metabolic dysfunctions. Furthermore, we demonstrate in vitro and in vivo that proinflammatory stimuli, and especially the TNFα, represses GIPR both in human and murine adipocytes, even though discordant results were obtained between human and murine cellular systems for other cytokines. Finally, we demonstrated that GIPR is negatively affected also by the excessive lipid engulfment. Overall, we report that obesogenic stimuli - ie. pro-inflammatory cytokines and the increased lipid accumulation - and PPARγ synthetic ligands oppositely modulate GIPR expression, possibly influencing the effectiveness of GIP agonists.