Peroxisome Proliferator Research Articles

Unveiling the potential of marine-derived diterpenes from the order Alcyonacea as promising anti-obesity agents

Metabolic syndrome (MS) represents a global health challenge characterized by various metabolic disorders, including HOMA-IR (insulin resistance), obesity, dyslipidemia, and hypertension. In our pursuit of identifying natural alternatives for the development of effective and safe anti-obesity medications, we examined the potential of the methanolic extract of the Red Sea derived soft coral Sarcophyton glaucum, where serum levels of glucose, insulin, HOMA-IR, lipid profile, fetuin A and B, PTP1Β (Protein tyrosine phosphatase 1B), adropin and omentin were determined. Furthermore, the expression of the UCP1 (Uncoupling protein 1) and PPARGC1A (Peroxisome proliferator–activated receptor-g coactivator-1a) genes have been assessed, to evaluate the anti-obesity potential of S. glaucum organic extract. Our findings demonstrated a significant decrease in glucose, HOMA-IR, cholesterol, triglyceride, LDL-C, fetuin A and B, and PTP1Β levels, accompanied by a significant increase in insulin, HDL-C, adropin, omentin, UCP1, and PPARGC1A expression after treatment with the soft coral extract. These promising outcomes can be attributed to the remarkable ingredients present in the extract, which were further supported by histopathological findings. In addition, a virtual screening protocol including molecular docking (MDock) and Structure-Activity Relationships (SARs) of 27 marine diterpenes was also explored to identify potential PTP1Β inhibitors targeting simultaneously the catalytic site and allosteric site, as well as fetuin A modulators. Moreover, the six most promising predicted marine diterpenes (4, 8, 9, 10, 13 and 14) were investigated for their pharmacokinetic properties, druglike nature and medicinal chemistry friendliness using the SwissADME platform. Of these, four marine diterpenes (4, 8, 9, and 10) were predicted to exhibit the appropriate drug-like properties.

Evaluation of the Antidiabetic Activities of the Fruit of Parquetina nigrescens (Afzel.) Bullock and In Silico Identification of Its Antidiabetic Agent.

The study investigated the antidiabetic potentials of the fruit extract of Parquetina nigrescens with the aim of justifying its folkloric antidiabetic usage in some part of Nigeria. Acute toxicity test of the plant extract was assessed using Lorke's method. Its antidiabetic activities were assayed in α-amylase, α-glucosidase, glucose, and streptozotocin-induced diabetic rats' models at various doses with acarbose and glibenclamide (5 mg/kg) as positive controls. Molecular docking studies were performed to identify the antidiabetic constituent of the extract and elucidate its possible mechanism of action. The estimated median lethal dose (LD50) of the extract was above 5000 mg/kg. In the α-amylase, α-glucosidase study, the extract elicited concentration-dependent activity similar to acarbose. In the glucose-induced hyperglycaemic model, 200 mg/kg of the extract was the most effective dose with comparable (P > .05) antihyperglycaemic activity to glibenclamide (5 mg kg) at 1 to 4 h. Also in the streptozotocin-induced diabetic rats model, 100 and 200 mg/kg of the extract gave comparable (P > 0.05) activity on days 4 to 14 that were significantly better than that of glibenclamide on days 4 to 7. The n-hexane and ethylacetate fractions of the extract, both at 200 mg/kg were the most active with comparable activity to glibenclamide at all time points. The molecular docking studies identified isorhoifolin as the best binder against alpha amylase with binding energy (-9.1 kcal/mol), alpha glucosidase (-9.4 kcal/mol), sodium-glucose cotransporter-2 (-9.5 kcal/mol), peroxisome proliferator activated receptor gamma (-10.3 kcal/mol), 11β-Hydroxysteroid dehydrogenase (-10.8 kcal/mol), and dipeptidyl peptidase IV (-9.4 kcal/mol). The results of the antidiabetic study of P nigrescence fruit extract justified its usage in ethnomedicne in diabetes management.

Is there still a place for fenofibrate-statin combination therapy?

Although low-density lipoprotein cholesterol (LDL-C) is the main target for the prevention of atherosclerotic cardiovascular disease (ASCVD), hypertriglyceridaemia (HTG), a common condition characterised by elevated blood triglyceride (TG) levels, contributes to residual cardiovascular risk independently of LDL-C levels. Elevated TG levels are a feature of atherogenic dyslipidaemia, which also includes low HDL-C levels and high levels of atherogenic small, dense LDL, together with accumulation of atherogenic remnant particles. Treatment of HTG includes lifestyle interventions, but these are not always sufficient to significantly reduce TG levels in people at high cardiovascular risk. Current guidelines for the treatment of dyslipidaemias recommend the use of statins as the first choice in people with HTG (TG >200 mg/dL) and high CV risk, and consideration of the use of specific TG-lowering drugs, such as fenofibrate, bezafibrate or icosapent ethyl if HTG persists. Fenofibrate acts by activating the peroxisome proliferator receptor alpha (PPARα), a nuclear receptor that plays an important role in lipid and lipoprotein metabolism, glucose homeostasis and inflammation. Several clinical trials have shown that fibrates may reduce the incidence of major cardiovascular events only in patients with high TG levels and low HDL-C levels, a finding that was also observed with fenofibrate in combination with a statin compared to statin therapy alone. The recent failure of the PROMINENT trial with pemafibrate in combination with a statin highlighted the notion that treatment with fibrates provides a clinical benefit only if they lower apoB levels.

Molecular Approach to Identify Anti-inflammatory Potential of Stevioside in HFD-induced Type 2 Diabetic Rats: Evidence From in Vivo Study

Stevioside is a natural sweetener derived from the leaves of the Stevia rebaudiana plant. It has gained popularity as a sugar substitute due to its intense sweetness without adding calories or affecting blood sugar levels, making it a suitable option for people with diabetes or those looking to reduce their sugar intake. Studies have shown that stevioside has glucose lowering effects. Previous studies have shown that it has significant role in skeletal muscle but its role on expression of inflammatory signaling molecules in adipose tissue against high diet and sucrose-induced type-2 diabetes in experimental rats is yet to be done. The current research was undertaken to investigate if stevioside could also exert its antidiabetic effects by circumventing adipocyte induced inflammation, a key driving factor for insulin resistance in obese individuals. Effective dose of stevioside (20 mg/kg b.wt) was administered orally for 45 days to high fat diet and sucrose induced type-2 diabetic rats. Interestingly, stevioside treatment restores the elevated serum levels of proinflammatory cytokines including tumor necrosis factor-α (TNF-α) and sterol regulatory element binding protein-1c (SREBP-1c) and enhances Peroxisome Proliferator–activated receptor-γ (PPAR-γ) in adipocytes of diabetic rats. The gene expression of IR, GLUT4 and PPAR-γ mRNA were also significantly activated in stevioside treated groups but reduced IL-1 beta, IlL-6, IKKB, TNF-alpha and NFkB mRNA expression in diabetic adipose tissue. More importantly, stevioside acts very effectively as metformin to circumvent inflammation and insulin resistance in diabetic rats. Our results clearly show that stevioside inhibits obesity induced insulin resistance by ameliorating the inflammatory events and upregulating insulin signalling molecules. Keywords: Stevioside, HFD-T2DM, pro inflammation, insulin signalling; adipose tissue, obesity; signaling pathways; Therapautics.

Fluorinated thiazole–thiosemicarbazones hybrids as potential PPAR-γ agonist and α-amylase, α-glucosidase antagonists: Design, synthesis, in silico ADMET and docking studies and hypoglycemic evaluation

In addition to Peroxisome Proliferator-Activated Receptor-gamma (PPAR-γ), which is essential for controlling type-2 diabetes mellitus, α-amylase and α-glucosidase inhibition is a key strategy in managing postprandial hyperglycemia. In this work a series of 2-(1-(2-((4-fluorophenyl)amino)-4-methylthiazol-5-yl)ethylidene)hydrazine-1-carbothioamide derivatives (3–6) was designed and synthesized through theiosemicarbazide derivatives, the structural elucidation of the new synthesized compounds was established using elemental and spectroscopic analyses. The antidiabetic activities of the new thiazole-thiosemicarbazone hybrids were screened in vivo for blood glucose lowering activity in normal rats and compared with pioglitazone as antidiabetic standard. Male Sprague-Dawley rats had reduced blood sugar levels after exposure to compounds 5 and 6 compared to pioglitazone. Additionally, the PPAR-γ agonist activity of compounds 5 and 6 as well as their ability to inhibit α-amylase and α-glucosidase were assessed. When compared to standard acarbose, which had an IC50 value of 0.74 ± 0.15 mM/mL, compound 5 showed the highest α-glucosidase inhibitory activity with IC50 value of 0.446 ± 0.01 mM/mL, while compound 6 showed good activity with an IC50 value of 1. 914 ± 0.04 mM/mL. However, compound 5 and compound 6 had weak α-amylase inhibitory activity, with IC50 values of 11.78 ± 0.58 and 24.18 ± 1.2 µg/mL respectively. Furthermore, Peroxisome proliferator activated receptor γ [PPAR-γ] agonist activity for compound 5 and compound 6 was assessed and gave promising result as [PPAR-γ] agonist with IC50 value of 0.938 ± 0.023 and 0.947 ± 0.024 ng/mL respectively superior to that of pioglitazone with IC50 value of 1.912 ± 0.11 ng/mL. All the results supported compound 5 as promising candidates for construction of new antidiabetic agents. Also, in silico ADMET and docking studies for the most promising derivatives 5, 6, Acarbose, and Pioglitazone were done.

FABP5 can substitute for androgen receptor in malignant progression of prostate cancer cells.

Fatty acid‑binding protein 5 (FABP5) and androgen receptor (AR) are critical promoters of prostate cancer. In the present study, the effects of knocking out the FABP5 or AR genes on malignant characteristics of prostate cancer cells were investigated, and changes in the expression of certain key proteins in the FABP5 (or AR)‑peroxisome proliferator activated receptor‑γ (PPARγ)‑vascular endothelial growth factor (VEGF) signaling pathway were monitored. The results obtained showed that FABP5‑ or AR‑knockout (KO) led to a marked suppression of the malignant characteristics of the cells, in part, through disrupting this signaling pathway. Moreover, FABP5 and AR are able to interact with each other to regulate this pathway, with FABP5 controlling the dominant AR splicing variant 7 (ARV7), and AR, in return, regulates the expression of FABP5. Comparisons of the RNA profiles revealed the existence of numerous differentially expressed genes (DEGs) comparing between the parental and the FABP5‑ or AR‑KO cells. The six most abundant changes in DEGs were found to be attributable to the transition from androgen‑responsive to androgen‑unresponsive, castration‑resistant prostate cancer (CRPC) cells. These findings have provided novel insights into the complex molecular pathogenesis of CRPC cells, and have demonstrated that interactions between FABP5 and AR contribute to the transition of prostate cancer cells to an androgen‑independent state. Moreover, gene enrichment analysis revealed that the most highly enriched biological processes associated with the DEGs included those responsive to fatty acids, cholesterol and sterol biosynthesis, as well as to lipid and fatty acid transportation. Since these pathways regulated by FABP5 or AR may be crucial in terms of transducing signals for cancer cell progression, targeting FABP5, AR and their associated pathways, rather than AR alone, may provide a new avenue for the development of therapeutic strategies geared towards suppressing the malignant progression to CRPC cells.

Therapeutic targets for metabolic dysfunction-associated steatotic liver disease and their roles in hepatocellular carcinoma

Metabolic dysfunction-associated steatotic liver disease (MASLD) is one of the most common chronic liver diseases. Over time, there has been a significant increase in the prevalence of MASLD. It has become one of the leading causes of hepatocellular carcinoma (HCC) in the United States, France, and the United Kingdom. Globally, the incidence of HCC related to MASLD may further increase with the growing prevalence of obesity. Non-alcoholic steatohepatitis (NASH) is an important stage of MASLD, which is more likely to cause cirrhosis and even HCC. And patients with NASH cirrhosis have a much higher incidence of hepatocellular cancer than patients with non-cirrhotic MASLD. As a result, it is critical to investigate the targets of MASLD therapy in HCC. This article reviews therapeutic targets of MASLD, such as farnesoid X receptor (FXR), peroxisome proliferator activated receptor (PPAR), fibroblast growth factor-21 (FGF-21), etc., and introduces the drugs related to these targets and their mechanisms of action in HCC. In addition, the developmental process and pathogenesis of MASLD, as well as risk factors for HCC development, are discussed. These are of great significance for the prevention and treatment of HCC.

Platelet-derived growth factor receptor beta is required for embryonic specification and confinement of the adult white adipose lineage

White adipose tissue (WAT) development and adult homeostasis rely on distinct adipocyte progenitor cells (APCs). While adult APCs are defined early during embryogenesis and generate adipocytes after WAT organogenesis, the mechanisms underlying adult adipose lineage determination and preservation remain undefined. Here, we uncover a critical role for platelet-derived growth factor receptor beta (Pdgfrβ) in identifying the adult APC lineage. Without Pdgfrβ, APCs lose their adipogenic competency to incite fibrotic tissue replacement and inflammation. Through lineage tracing analysis, we reveal that the adult APC lineage is lost and develops into macrophages when Pdgfrβ is deleted embryonically. Moreover, to maintain the APC lineage, Pdgfrβ activation stimulates p38/MAPK phosphorylation to promote APC proliferation and maintains the APC state by phosphorylating peroxisome proliferator activated receptor gamma (Pparγ) at serine 112. Together, our findings identify a role for Pdgfrβ acting as a rheostat for adult adipose lineage confinement to prevent unintended lineage switches.

Gene expression and trace elements in Greenlandic ringed seals (Pusa hispida)

Marine top predators such as ringed seals biomagnify environmental contaminants; and with the increasing human activities in the Arctic, ringed seals are exposed to biologically significant concentrations of trace elements resulting in reproductive impairment, immunosuppression, and neurological damages. Little is known about the molecular effects of heavy metals on these vulnerable apex predators suffering from a rapidly changing Arctic with significant loss of sea-ice. In the present study, concentrations of cadmium (Cd), mercury (Hg) and selenium (Se) were measured in liver of sixteen Greenlandic ringed seals (nine adults and seven subadults) together with molecular biomarkers involved in bio-transformation, oxidative stress, endocrine disruption and immune activity in blood and blubber. The concentrations of trace elements increased in the following order: Hg > Se > Cd with levels of mercury and selenium being highest in adults. Aryl hydrocarbon receptor nuclear translocator (ARNT), peroxisome proliferator activated receptor alpha (PPARα, estrogen receptor alpha (ESR1), thyroid hormone receptor alpha (TRα) and interleukin – 2 (IL-2) mRNA transcript levels were highest in blubber, while heat shock protein 70 (HSP70) and interleukin – 10 (IL-10) were significantly higher in blood. There were no significant correlations between the concentrations of trace elements and mRNA transcript levels suggesting that stressors other than the trace elements investigated are responsible for the changes in gene expression levels. Since Hg seems to increase in Greenlandic ringed seals, there is a need to re-enforce health monitoring of this ringed seal population.

Protective mechanism of Paeoniae Radix Alba against chemical liver injury based on network pharmacology, molecular docking, and in vitro experiments

ObjectiveTo explore and validate the potential targets of Paeoniae Radix Alba (P. Radix, Bai Shao) in protecting against chemical liver injury through network pharmacology, molecular docking technology, and in vitro cell experiments. MethodsNetwork pharmacology was used to identify the common potential targets of P. Radix and chemical liver injury. Molecular docking was used to fit the components, which were subsequently verified in vitro. A cell model of hepatic fibrosis was established by activating hepatic stellate cell (HSC)-LX2 cells with 10 ng/mL transforming growth factor-β1. The cells were exposed to different concentrations of total glucosides of paeony (TGP), the active substance of P. Radix, and then evaluated using the cell counting kit-8 assay, enzyme-linked immunosorbent assay, and western blot. ResultsAnalysis through network pharmacology revealed 13 key compounds of P. Radix, and the potential targets for preventing chemical liver injury were IL-6, AKT serine/threonine kinase 1, jun proto-oncogene, heat shock protein 90 alpha family class A member 1 (HSP90AA1), peroxisome proliferator activated receptor gamma (PPARG), PTGS2, and CASP3. Gene Ontology (GO) enrichment analysis indicated the involvement of response to drugs, membrane rafts, and peptide binding. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that the main pathways involved lipid and atherosclerosis and chemical carcinogenesis-receptor activation. Paeoniflorin and albiflorin exhibited strong affinity for HSP90AA1, PTGS2, PPARG, and CASP3. Different concentrations of TGP can inhibit the expression of COL-Ⅰ, COL-Ⅲ, IL-6, TNF-α, IL-1β, HSP-90α, and PTGS2 while increasing the expression of PPAR-γ and CASP3 in activated HSC-LX2 cells. ConclusionP. Radix primarily can regulate targets such as HSP90AA1, PTGS2, PPARG, CASP3. TGP, the main active compound of P. Radix, protects against chemical liver injury by reducing the inflammatory response, activating apoptotic proteins, and promoting the apoptosis of activated HSCs.

Targeted Deletion of Pparβ/δ in Myeloid Cells Enhances Their Tumor-Promoting Function

Peroxisome proliferator activated receptors (PPARs) are transcription factors of the nuclear hormone transcription superfamily. Thee different PPAR subtypes have been described, PPARalpha (PPARα), PPARgamma (PPARγ), and PPARbeta/delta (PPARβ/δ), with distinct tissue-specific allocations. All PPARs have been shown to be expressed in immune cells and, due to their ability to regulate lipid metabolism, these transcription factors can affect immune cell differentiation and function. While the effects of PPARα and PPARγ on M2 macrophage polarization are well established, the role of PPARβ/δ in myeloid cells is less studied. In the context of autoimmunity, it was shown that targeted deletion of PPARβ/δ in the myeloid compartment altered the Th1/Th17 polarization of CD4+ cells, and exacerbated experimental autoimmune encephalomyelitis in mice. In tumor mouse models, it was reported that M-CSF secreted by tumor cells could activate PPARβ/δ in tumor infiltrating myeloid cells, resulting in upregulation of genes responsible for their tumor-promoting properties such as IL-10, ARG-1 and VEGF. To investigate how PPARβ/δ can affect the myeloid cell responses in tumor immunity, we combined genetic and pharmacologic approaches. We generated mice with conditional targeting of Pparβ/δ gene and crossed them with LysMCre ( Pparβ/δ f/fLysMCre) to delete Pparβ/δ in myeloid cells. We used the MC38 colon adenocarcinoma syngeneic mouse tumor model and after implantation of tumor cells in Pparβ/δ f/fLysMCre and Pparβ/δ f/f control mice, we monitored tumor growth. Surprisingly, in contrast to what has been previously reported, we observed significantly larger and heavier tumors in PPAR β / δ f/fLysMCre mice compared to control mice, indicating that selective deletion of Pparβ/δ in the myeloid compartment was sufficient to impair anti-tumor immune responses in vivo. We assessed the intratumoral immune infiltrates including CD11b +F4/80 + tumor-associated macrophages (TAMs), CD11b +Ly6C hiLy6G - monocytic (M-MDSC), and CD11b +Ly6C loLy6G + polymorphonuclear (PMN-MDSC) MDSCs by flow cytometry. Although no numerical differences were detected in these populations between the two experimental groups, all myeloid cells isolated from tumor bearing Ppar β / δ f/fLysMCre mice demonstrated a less activated and pro-inflammatory phenotype, as indicated by lower levels of IFN-g expression. Notably, CD38 and CD88, two markers that have been associated with enhanced suppressive properties of MDSCs, were significantly upregulated in M-MDSCs and PMN-MDSC from Ppar β / δ f/fLysMCre tumor bearing mice compared to control Pparβ/δ f/f tumor-bearing mice. Hence, we sought to investigate how Pparβ/δ affects the suppressor properties of MDSCs. By using magnetic beads, we isolated GR1 + MDSC from the spleens of tumor-bearing Ppar β / δ f/fLysMCre and control mice and assessed suppression function in co-cultures with OTI TCR-transgenic T cells stimulated with cognate antigen, by DNA synthesis. Suppression capacity of MDSC from Ppar β / d f/fLysMCre tumor-bearing mice was significantly enhanced compared to MDSC from control tumor bearing mice. These results indicate that conditional deletion of Pparβ/δ in the myeloid cells prevented myeloid cell activation and augmented MDSCs suppressor properties by cell intrinsic mechanisms resulting in acceleration of tumor growth.

Gga-let-7a-3p inhibits the proliferation and differentiation of chicken intramuscular preadipocytes

ABSTRACT 1. Intramuscular fat (IMF) is a key parameter for chicken meat quality. IMF deposition is driven by genetic, nutritional and management factors, with genetics being the determining factor. Previous whole transcriptome sequencing revealed that microRNA gga-let-7a-3p was related to lipid metabolism in breast muscle. This study further investigated the potential role of gga-let-7a-3p in IMF deposition. 2. The mimic and inhibitor of gga-let-7a-3p were individually transfected into chicken intramuscular preadipocytes. Subsequently, the proliferation and differentiation states of the cells were detected. Transcriptome sequencing was performed on cells transfected with gga-let-7a-3p mimic. 3. The results indicated that gga-let-7a-3p suppressed the mRNA levels of proliferation and differentiation-related genes, as well as the protein levels. EdU and Oil Red O assays revealed that gga-let-7a-3p restrained preadipocyte proliferation and differentiation. In addition, a total of 333 up-regulated genes and 807 down-regulated genes were identified in cells transfected with gga-let-7a-3p mimic. Using Kyoto Encyclopaedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis, differential genes were found to be enriched in processes such as the peroxisome proliferator activated receptor (PPAR) signalling pathway and oxidative phosphorylation. 4. The study demonstrated that gga-let-7a-3p inhibits the proliferation and differentiation of chicken intramuscular preadipocytes, which provides new understanding to further unravel the function of gga-let-7a-3p.

Effect of acupuncture on arthritic pathological injury in rats with type Ⅱ collagen-induced rheumatoid arthritis.

To observe the effect of acupuncture stimulation of "Yanglingquan"(GB34), "Zusanli"(ST36) and "Xuanzhong" (GB39) on arthritis index (AI), joint synovial membrane pathology, serum-related immunoinflammatory factors, and expressions of tumor suppressor gene mt-p53, nuclear factor kappa B (NF-κB) and peroxisome proliferator activated receptor gamma (PPARγ) in knee joint synovial tissue of rats with type Ⅱ collagen-induced arthritis (CIA), so as to explore its possible mechanisms underlying improvement of rheumatoid arthritis (RA). Male SD rats were used in the present study. The CIA model was established by subcutaneous injection of collagen emulsion (200 μL/rat) in the tail root region on the first day and repeat (100 μL/rat) once on the 9th day. Eighteen successful CIA rats were randomized into model, medication and acupuncture groups, with 6 rats in each group. Other 6 normal rats were used as the normal control group. For rats of the medication group, leflunomide (1.9 mg/kg) was administrated by gavage, once a day, and for rats of the acupuncture group, manual acupuncture stimulation was applied to bilateral GB34, ST36, GB39 for 30 min, once a day, for 12 weeks. The arthritis index (AI) score (0-4 points) was evaluated once every week. The contents of IL-6, IL-17 and TNF-α in the serum were determined by ELISA. Histopathological changes of the ankle joint were observed by H.E. staining. The protein and mRNA expression levels of mt-p53, NF-κB p65, and PPARγ in the knee joint synovial tissue were determined by Western blot and quantitative real time PCR, separately. Compared with the normal control group, the AI scores at different time-points after modeling, contents of serum TNF-α, IL-6 and IL-17, expression levels of mt-p53, NF-κB p65, PPARγ proteins and mRNAs were significantly increased in the model group (P<0.01, P<0.05). In comparison with the model group, the AI scores at the 10th week in the medication group and at the 3rd, 9th and 10th week in the acupuncture group, contents of serum TNF-α, IL-6 and IL-17, and the expression levels of mt-p53 and NF-κB p65 proteins in both medication and acupuncture groups, as well as mt-p53 and NF-κB p65 mRNAs in the medication group were apparently decreased (P<0.01, P<0.05), while the expression levels of PPARγ protein in both medication and acupuncture group and PPARγ mRNA in the medication group were significantly up-regulated (P<0.05, P<0.01). No significant differences were found between the acupuncture and medication groups in down-regulating the AI score and serum TNF-α, IL-6 and IL-17 contents. The effect of acupuncture was weaker than that of medication in down-regulating the expression of mt-p53 and NF-κB p65 proteins and mRNAs and in up-regulating PPARγ mRNA (P<0.01). H.E. results showed ankle cartilage hyperplasia, reduced joint cavity, mild fibroproliferation and inflammatory cell infiltration in the surrounding soft tissue of the ankle joint in rats of the model group, which was milder in both medication and acupuncture groups. Acupuncture stimulation can improve the degree of joint inflammation and swelling in CIA rats, which may be related to its effects in inhibiting the overexpression of immunoinflammatory factors in serum and regulating expression of mt-p53, NF-κB p65, PPARγ mRNAs and proteins in the synovial tissue.

Lysine β-hydroxybutyrylation promotes lipid accumulation in alcoholic liver disease

Continuous (chronic or sub-chronic) alcohol consumption induces a metabolic byproduct known as ketone bodies, and the accumulation of ketones leads to a life-threatening syndrome called alcoholic ketoacidosis. However, the mechanism underlining the physiological effects of ketone accumulation in alcoholic liver disease (ALD) is still in its infancy. Here, we discovered that mitochondrial acetyl-CoA accumulation was diverted into the ketogenesis pathway in ethanol-fed mice and ethanol-exposed hepatocytes. Unexpectedly, global protein lysine β-hydroxybutyrylation (Kbhb) was induced in response to increased ketogenesis-derived β-hydroxybutyrate (BHB) levels both in hepatocytes and in livers of mice. Focusing on the solute carrier family (SLCs), we found that SLC25A5 presented obvious Kbhb at lysine residues 147 and 166. Kbhb modifications at these two lysine residues stabilized SLC25A5 expression by blocking ubiquitin–proteasome pathway. Subsequent mutation analysis revealed that Kbhb of SLC25A5 at K147 and K166 had site-specific regulatory roles by increasing peroxisome proliferator activated receptor gamma (PPARγ) expression, which further promoting lipogenesis. Additionally, 3-hydroxy-3-methylglutaryl-coenzyme A synthase 2 (HMGCS2), a rate-limiting enzyme for BHB production, was profoundly induced by ethanol exposure, and knockout of Hmgcs2 with CRISPR/Cas9 attenuated SLC25A5 Kbhb. Together, our study demonstrated a widespread Kbhb landscape under ethanol exposure and clarified a physiological effect of Kbhb modification on liver lipid accumulation.

The 2023 Walter B. Cannon Award Lecture: Mechanisms Regulating Vascular Function and Blood Pressure by the PPARγ-RhoBTB1-CUL3 Pathway.

Human genetic and clinical trial data suggest that peroxisome proliferator activated receptor γ (PPARγ), a nuclear receptor transcription factor plays an important role in the regulation of arterial blood pressure. The examination of a series of novel animal models, coupled with transcriptomic and proteomic analysis, has revealed that PPARγ and its target genes employ diverse pathways to regulate vascular function and blood pressure. In endothelium, PPARγ target genes promote an antioxidant state, stimulating both nitric oxide (NO) synthesis and bioavailability, essential components of endothelial-smooth muscle communication. In vascular smooth muscle, PPARγ induces the expression of a number of genes that promote an antiinflammatory state and tightly control the level of cGMP, thus promoting responsiveness to endothelial-derived NO. One of the PPARγ targets in smooth muscle, Rho related BTB domain containing 1 (RhoBTB1) acts as a substrate adaptor for proteins to be ubiquitinated by the E3 ubiquitin ligase Cullin-3 and targeted for proteasomal degradation. One of these proteins, phosphodiesterase 5 (PDE5) is a target of the Cullin-3/RhoBTB1 pathway. Phosphodiesterase 5 degrades cGMP to GMP and thus regulates the smooth muscle response to NO. Moreover, expression of RhoBTB1 under condition of RhoBTB1 deficiency reverses established arterial stiffness. In conclusion, the coordinated action of PPARγ in endothelium and smooth muscle is needed to maintain NO bioavailability and activity, is an essential regulator of vasodilator/vasoconstrictor balance, and regulates blood vessel structure and stiffness.

GW0742 reduces mast cells degranulation and attenuates neurological impairments via PPARβ/δ/CD300a/SHP1 pathway after GMH in neonatal rats

BackgroundActivation of mast cells plays an important role in brain inflammation. CD300a, an inhibitory receptor located on mast cell surfaces, has been reported to reduce the production of pro-inflammatory cytokines and exert protective effects in inflammation-related diseases. Peroxisome proliferator–activated receptor β/δ (PPARβ/δ), a ligand-activated nuclear receptor, activation upregulates the transcription of CD300a. In this study, we aim to investigate the role of PPARβ/δ in the attenuation of germinal matrix hemorrhage (GMH)-induced mast cell activation via CD300a/SHP1 pathway. MethodsGMH model was induced by intraparenchymal injection of bacterial collagenase into the right hemispheric ganglionic eminence in P7 Sprague Dawley rats. GW0742, a PPARβ/δ agonist, was administered intranasally at 1 h post-ictus. CD300a small interfering RNA (siRNA) and PPARβ/δ siRNA were injected intracerebroventricularly 5 days and 2 days before GMH induction. Behavioral tests, Western blot, immunofluorescence, Toluidine Blue staining, and Nissl staining were applied to assess post-GMH evaluation. ResultsResults demonstrated that endogenous protein levels of PPARβ/δ and CD300a were decreased, whereas chymase, tryptase, IL-17A and transforming growth factor β1 (TGF-β1) were elevated after GMH. GMH induced significant short- and long-term neurobehavioral deficits in rat pups. GW0742 decreased mast cell degranulation, improved neurological outcomes, and attenuated ventriculomegaly after GMH. Additionally, GW0742 increased expression of PPARβ/δ, CD300a and phosphorylation of SHP1, decreased phosphorylation of Syk, chymase, tryptase, IL-17A and TGF-β1 levels. PPARβ/δ siRNA and CD300a siRNA abolished the beneficial effects of GW0742. ConclusionsGW0742 inhibited mast cell-induced inflammation and improved neurobehavior after GMH, which is mediated by PPARβ/δ/CD300a/SHP1 pathway. GW0742 may serve as a potential treatment to reduce brain injury for GMH patients.

Improving Shelf Life and Content of Unsaturated Fatty Acids in Meat of Lambs Fed a Diet Supplemented with Grape Dregs.

This study was conducted to evaluate the potential effects of dietary grape residue levels on the slaughter indicators, meat quality, meat shelf-life, unsaturated fatty acid content, and expression of fatty acid deposition genes in the muscle of lambs. Sixty 30-month-old male Dorper and Small-Tailed Han F1 hybrid lambs were assigned to a single factor complete randomized trial design and fed with four different diets including 0%, 8%, 16%, and 24% grape dregs, respectively. The findings regarding meat production efficacy in the lambs revealed substantial differences. The control group showed notably lower dressing percentage, carcass weight, net meat weight, meat percentage concerning carcass, meat-to-bone ratio, relative visceral and kidney fat mass, and rib eye area compared to the other groups (p < 0.05). Additionally, the meat shearing force of lambs fed a diet with 16% grape pomace (GP) was significantly higher than that of the 24% GP group (p < 0.05), while the 24 h meat color parameter a* value of the control group was notably higher than that of the 8% GP group (p < 0.05). In addition, compared to the control group, lambs fed with a diet containing 16% GP had higher levels of oleic acid (C18:1n-9c), linoleic acid (C18:2n-6c), behenic acid (C22:0), tricosanoic acid (C23:0), lignoceric acid (C24:0), and conjugated linoleic acid (CLA), at a ratio of ∑CLA/TFA, ∑n-6, ∑MUFA, and ∑PUFA in the longissimus dorsi muscle (p < 0.05), but the reverse case was applicable for Total Volatile Basic Nitrogen (TVB-N) content (p < 0.05). GP supplementation did not substantially affect the expression of stearoyl-CoA desaturase (SCD), peroxisome proliferator activated receptor alpha (PPARα), and peroxisome proliferator-activated receptor gamma (PPARγ) genes (p > 0.05). The findings indicated that incorporating grape dregs in the diets of fattening lambs leads to notable enhancements in meat production and the antioxidant capacity of lamb meat, and effectively extends the shelf life of the meat.

Combination of computational new approach methodologies for enhancing evidence of biological pathway conservation across species

The ability to predict which chemicals are of concern for environmental safety is dependent, in part, on the ability to extrapolate chemical effects across many species. This work investigated the complementary use of two computational new approach methodologies to support cross-species predictions of chemical susceptibility: the US Environmental Protection Agency Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS) tool and Unilever's recently developed Genes to Pathways – Species Conservation Analysis (G2P-SCAN) tool. These stand-alone tools rely on existing biological knowledge to help understand chemical susceptibility and biological pathway conservation across species. The utility and challenges of these combined computational approaches were demonstrated using case examples focused on chemical interactions with peroxisome proliferator activated receptor alpha (PPARα), estrogen receptor 1 (ESR1), and gamma-aminobutyric acid type A receptor subunit alpha (GABRA1). Overall, the biological pathway information enhanced the weight of evidence to support cross-species susceptibility predictions. Through comparisons of relevant molecular and functional data gleaned from adverse outcome pathways (AOPs) to mapped biological pathways, it was possible to gain a toxicological context for various chemical-protein interactions. The information gained through this computational approach could ultimately inform chemical safety assessments by enhancing cross-species predictions of chemical susceptibility. It could also help fulfill a core objective of the AOP framework by potentially expanding the biologically plausible taxonomic domain of applicability of relevant AOPs.

Cytosolic phospholipase A2 regulates lipid homeostasis under osmotic stress through PPARγ.

Physiologically, renal medullary cells are surrounded by a hyperosmolar interstitium. However, different pathological situations can induce abrupt changes in environmental osmolality, causing cell stress. Therefore, renal cells must adapt to survive in this new condition. We previously demonstrated that, among the mechanisms involved in osmoprotection, renal cells upregulate triglyceride biosynthesis (which helps preserve glycerophospholipid synthesis and membrane homeostasis) and cyclooxygenase-2 (which generates prostaglandins from arachidonic acid) to maintain lipid metabolism in renal tissue. Herein, we evaluated whether hyperosmolality modulates phospholipase A2 (PLA2 ) activity, leading to arachidonic acid release from membrane glycerophospholipid, and investigated its possible role in hyperosmolality-induced triglyceride synthesis and accumulation. We found that hyperosmolality induced PLA2 expression and activity in Madin-Darby canine kidney cells. Cytosolic PLA2 (cPLA2) inhibition, but not secreted or calcium-independent PLA2 (sPLA2 or iPLA2 , respectively), prevented triglyceride synthesis and reduced cell survival. Inhibition of prostaglandin synthesis with indomethacin not only failed to prevent hyperosmolality-induced triglyceride synthesis but also exacerbated it. Similar results were observed with the peroxisomal proliferator activated receptor gamma (PPARγ) agonist rosiglitazone. Furthermore, hyperosmolality increased free intracellular arachidonic acid levels, which were even higher when prostaglandin synthesis was inhibited by indomethacin. Blocking PPARγ with GW-9662 prevented the effects of both indomethacin and rosiglitazone on triglyceride synthesis and even reduced hyperosmolality-induced triglyceride synthesis, suggesting that arachidonic acid may stimulate triglyceride synthesis through PPARγ activation. These results highlight the role of cPLA2 in osmoprotection, since it is essential to provide arachidonic acid, which is involved in PPARγ-regulated triglyceride synthesis, thus guaranteeing cell survival.

Exosomes derived from human dermal fibroblasts (HDFn-Ex) alleviate DNCB-induced atopic dermatitis (AD) via PPARα.

Atopic dermatitis (AD) is a chronic inflammatory skin disease. Skin barrier dysfunction is the initial step in the development of AD. Recently, exosomes have been considered as potential cell-free medicine for skin defects such as aging, psoriasis and wounds. The aim of this study was to investigate the effects of human dermal fibroblast-neonatal-derived exosome (HDFn-Ex) on AD. HDFn-Ex increased the expression of peroxisome proliferator activated receptor α (PPARα) and alleviated the 1-chloro-2,4-dinitrobenzene (DNCB)-mediated downregulation of filaggrin, involucrin, loricrin, hyaluronic acid synthase 1 (HAS1) and HAS2 in human keratinocyte HaCaT cells. However, these effects were inhibited by the PPARα antagonist GW6471. In the artificial skin model, HDFn-Ex significantly inhibited DNCB-induced epidermal hyperplasia and the decrease in filaggrin and HAS1 levels via a PPARα. In the DNCB-induced AD-like mouse model, HDFn-Ex administration reduced epidermis thickening and mast cell infiltration into the dermis compared to DNCB treatment. Moreover, the decreases in PPARα, filaggrin and HAS1 expression, as well as the increases in IgE and IL4 levels induced by DNCB treatment were reversed by HDFn-Ex. These effects were blocked by pre-treatment with GW6471. Furthermore, HDFn-Ex exhibited an anti-inflammatory effect by inhibiting the DNCB-induced increases in IκBα phosphorylation and TNF-α expression. Collectively, HDFn-Ex exhibited a protective effect on AD. Notably, these effects were regulated by PPARα. Based on our results, we suggest that HDFn-Ex is a potential candidate for treating AD by recovering skin barrier dysfunction and exhibiting anti-inflammatory activity.