Involvement of prostacyclin synthase in high-fat-diet-induced obesity

Oxylipins Derived from PUFAs in Cardiometabolic Diseases: Mechanism of Actions and Possible Nutritional Interactions

Oxylipins are oxidized fatty acids, both saturated and unsaturated, formed through pathways that involve singlet oxygen or dioxygen-mediated oxygenation reactions and are primarily produced by enzyme families such as cyclooxygenases, lipoxygenases, and cytochrome P450. These lipid-based complex bioactive molecules are pivotal signal mediators, acting in a hormone-like manner in the pathophysiology of numerous diseases, especially cardiometabolic diseases via modulating plenty of mechanisms. It has been reported that omega-6 and omega-3 oxylipins are important novel biomarkers of cardiometabolic diseases. Moreover, collected literature has noted that diet and dietary components, especially fatty acids, can modulate these oxygenated lipid products since they are mainly derived from dietary omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) or linoleic acid and α-linolenic by elongation and desaturation pathways. This comprehensive review aims to examine their correlations to cardiometabolic diseases and how diets modulate oxylipins. Also, some aspects of developing new biomarkers and therapeutical utilization are detailed in this review.

Evaluating the impact of type 2 diabetes mellitus on pulmonary vascular function and the development of pulmonary fibrosis

The increasing prevalence of type 2 diabetes mellitus (T2DM) is a significant worldwide health concern caused by sedentary lifestyles and unhealthy diets. Beyond glycemic control, T2DM impacts multiple organ systems, leading to various complications. While traditionally associated with cardiovascular and microvascular complications, emerging evidence indicates significant effects on pulmonary health. Pulmonary vascular dysfunction and fibrosis, characterized by alterations in vascular tone and excessive extracellular matrix deposition, are increasingly recognized in individuals with T2DM. The onset of T2DM is often preceded by prediabetes, an intermediate hyperglycemic state that is associated with increased diabetes and cardiovascular disease risk. This review explores the relationship between T2DM, pulmonary vascular dysfunction and pulmonary fibrosis, with a focus on potential links with prediabetes. Pulmonary vascular function, including the roles of nitric oxide (NO), prostacyclin (PGI2), endothelin-1 (ET-1), thromboxane A2 (TxA2) and thrombospondin-1 (THBS1), is discussed in the context of T2DM and prediabetes. Mechanisms linking T2DM to pulmonary fibrosis, such as oxidative stress, dysregulated fibrotic signaling, and chronic inflammation, are explained. The impact of prediabetes on pulmonary health, including endothelial dysfunction, oxidative stress, and dysregulated vasoactive mediators, is highlighted. Early detection and intervention during the prediabetic stage may reduce respiratory complications associated with T2DM, emphasizing the importance of management strategies targeting blood glucose regulation and vascular health. More research that looks into the mechanisms underlying pulmonary complications in T2DM and prediabetes is needed.

Emerging Roles and Therapeutic Applications of Arachidonic Acid Pathways in Cardiometabolic Diseases

Cardiometabolic disease has become a major health burden worldwide, with sharply increasing prevalence but highly limited therapeutic interventions. Emerging evidence has revealed that arachidonic acid derivatives and pathway factors link metabolic disorders to cardiovascular risks and intimately participate in the progression and severity of cardiometabolic diseases. In this review, we systemically summarized and updated the biological functions of arachidonic acid pathways in cardiometabolic diseases, mainly focusing on heart failure, hypertension, atherosclerosis, nonalcoholic fatty liver disease, obesity, and diabetes. We further discussed the cellular and molecular mechanisms of arachidonic acid pathway-mediated regulation of cardiometabolic diseases and highlighted the emerging clinical advances to improve these pathological conditions by targeting arachidonic acid metabolites and pathway factors.

Photoperiod Conditions Modulate Serum Oxylipins Levels in Healthy and Obese Rats: Impact of Proanthocyanidins and Gut Microbiota

Seasonal rhythms are emerging as a key factor influencing gut microbiota and bioactive compounds functionality as well as several physiological processes such as inflammation. In this regard, their impact on the modulation of oxylipins (OXLs), which are important lipid mediators of inflammatory processes, has not been investigated yet. Hence, we aimed to investigate the effects of photoperiods on OXLs metabolites in healthy and obesogenic conditions. Moreover, we evaluated if the impact of proanthocyanidins and gut microbiota on OXLs metabolism is influenced by photoperiod in obesity. To this purpose, Fischer 344 rats were housed under different photoperiod conditions (L6: 6 h light, L12: 12 h light or L18:18 h light) and fed either a standard chow diet (STD) or a cafeteria diet (CAF) for 9 weeks. During the last 4 weeks, obese rats were daily administered with an antibiotic cocktail (ABX), an oral dose of a grape seed proanthocyanidin extract (GSPE), or with their combination. CAF feeding and ABX treatment affected OXLs in a photoperiod dependent-manner. GSPE significantly altered prostaglandin E2 (PGE2) levels, only under L6 and mitigated ABX-mediated effects only under L18. In conclusion, photoperiods affect OXLs levels influenced by gut microbiota. This is the first time that the effects of photoperiod on OXLs metabolites have been demonstrated.

Addition of ROCK Inhibitors Alleviates Prostaglandin-Induced Inhibition of Adipogenesis in 3T3L-1 Spheroids

To elucidate the additive effects of the ROCK inhibitors (ROCK-i), ripasudil (Rip) and Y27632 on bimatoprost acid (BIM-A), a prostaglandin analog (PG), on adipose tissue, two- and three-dimensional (2D or 3D) cultures of 3T3-L1 cells, the most well characterized cells in the field of lipid research, were used. The cells were subjected to a variety of analyses including lipid staining, real-time cellular metabolic analysis, the mRNA expressions of genes related to adipogenesis and extracellular matrices (ECMs) as well as the sizes and physical properties of the 3D spheroids by a micro-squeezer. BIM-A induced strong inhibitory effects on most of the adipogenesis-related changes in the 2D and 3D cultured 3T3-L1 cells, including (1) the enlargement and softening of the 3D spheroids, (2) a dramatic enhancement in lipid staining and the expression of adipogenesis-related genes, and (3) a decrease in mitochondrial and glycolytic metabolic function. By adding ROCK-i to the BIM-A, most of these BIM-A-induced effects were cancelled. The collective findings reported herein suggest that ROCK-i eliminated the PG-induced suppression of adipogenesis in the 3T3-L1 cells, accompanied by the formation of enlarged 3D spheroids. Such effects of adding ROCK-i to a PG in preadipocytes on cellular properties appear to be associated with the suppression of PG-induced adverse effects, and provide additional insight into our understanding of lipid-related research.

The biological actions of prostanoids in adipose tissue in physiological and pathophysiological conditions

Adipose tissue has been established as an endocrine organ that plays an important role in maintaining metabolic homeostasis. Adipose tissue releases several bioactive molecules called adipokines. Inflammation, dysregulation of adipokine synthesis, and secretion are observed in obesity and related diseases and cause adipose tissue dysfunction. Prostanoids, belonging to the eicosanoid family of lipid mediators, can be synthesized in adipose tissue and play a critical role in adipose tissue biology. In this review, we summarized the current knowledge regarding the interaction of prostanoids with adipokines, the expression of prostanoid receptors, and prostanoid synthase enzymes in adipose tissues in health and disease. Furthermore, the involvement of prostanoids in the physiological function or dysfunction of adipose tissue including inflammation, lipolysis, adipogenesis, thermogenesis, browning of adipocytes, and vascular tone regulation was also discussed by examining studies using pharmacological approaches or genetically modified animals for prostanoid receptors/synthase enzymes. Overall, the present review provides a perspective on the evidence from literature regarding the biological effects of prostanoids in adipose tissue. Among prostanoids, prostaglandin E2 (PGE₂) is prominent in regards to its substantial role in both adipose tissue physiology and pathophysiology. Targeting prostanoids may serve as a potential therapeutic strategy for preventing or treating obesity and related diseases.

Microsomal Prostaglandin E Synthase-1 (mPGES-1) is involved in the metabolic and cardiovascular alterations associated with obesity

BACKGROUND AND PURPOSE

Microsomal prostaglandin E synthase-1 (mPGES-1) is an inducible isomerase responsible for prostaglandin E₂ production in inflammatory conditions. We evaluated the role of mPGES-1 in obesity development and in the metabolic and cardiovascular alterations associated.

EXPERIMENTAL APPROACH

mPGES-1^+/+ and mPGES-1^-/- mice were fed with normal or high fat diet (HFD, 60% fat). The glycaemic and lipid profile was studied by glucose and insulin tolerance tests and colorimetric assays. Vascular function, structure and mechanics were evaluated by myography. Histological studies, q-RT-PCR and Western Blot analyses were performed in adipose tissue depots and cardiovascular tissues. Gene expression in abdominal fat and perivascular adipose tissue (PVAT) from patients and its correlation with vascular damage was determined.

KEY RESULTS

Male mPGES-1^-/- mice fed with HFD were protected against body weight gain and showed reduced adiposity, better glucose tolerance and insulin sensitivity, lipid levels and less white adipose tissue and PVAT inflammation and fibrosis, compared to mPGES-1^+/+ mice. mPGES-1 knockdown prevented cardiomyocyte hypertrophy, cardiac fibrosis, endothelial dysfunction, aortic insulin resistance, and vascular inflammation and remodeling, induced by HFD. Obesity-induced weight gain and endothelial dysfunction of resistance arteries were ameliorated in female mPGES-1^-/- mice. In humans, we found a positive correlation between mPGES-1 expression in abdominal fat and vascular remodeling, vessel stiffness and systolic blood pressure. In human PVAT, there was a positive correlation between mPGES-1 expression and inflammatory markers.

CONCLUSIONS AND IMPLICATIONS

mPGES-1 inhibition might be a novel therapeutic approach for the management of obesity and the associated cardiovascular and metabolic alterations.

Metabolite G-Protein Coupled Receptors in Cardio-Metabolic Diseases

G protein-coupled receptors (GPCRs) have originally been described as a family of receptors activated by hormones, neurotransmitters, and other mediators. However, in recent years GPCRs have shown to bind endogenous metabolites, which serve functions other than as signaling mediators. These receptors respond to fatty acids, mono- and disaccharides, amino acids, or various intermediates and products of metabolism, including ketone bodies, lactate, succinate, or bile acids. Given that many of these metabolic processes are dysregulated under pathological conditions, including diabetes, dyslipidemia, and obesity, receptors of endogenous metabolites have also been recognized as potential drug targets to prevent and/or treat metabolic and cardiovascular diseases. This review describes G protein-coupled receptors activated by endogenous metabolites and summarizes their physiological, pathophysiological, and potential pharmacological roles.

Absence of prostacyclin greatly relieves cyclophosphamide-induced cystitis and bladder pain in mice

Cyclophosphamide (CP) has been widely used in the treatment of various malignancies and autoimmune diseases, but acrolein, a byproduct of CP, causes severe hemorrhagic cystitis as the major side effect of CP. On the other hand, a large amount of prostacyclin (PGI₂ ) is produced in bladder tissues, and PGI₂ has been shown to play a critical role in bladder homeostasis. PGI₂ is biosynthesized from prostaglandin (PG) H₂ , the common precursor of PGs, by PGI₂ synthase (PTGIS) and is known to also be involved in inflammatory responses. However, little is known about the roles of PTGIS-derived PGI₂ in bladder inflammation including CP-induced hemorrhagic cystitis. Using both genetic and pharmacological approaches, we here revealed that PTGIS-derived PGI₂ -IP (PGI₂ receptor) signaling exacerbated CP-induced bladder inflammatory reactions. Ptgis deficiency attenuated CP-induced vascular permeability and chemokine-mediated neutrophil migration into bladder tissues and then suppressed hemorrhagic cystitis. Treatment with RO1138452, an IP selective antagonist, also suppressed CP-induced cystitis. We further found that cystitis-related nociceptive behavior was also relieved in both Ptgis^-/- mice and RO1138452-treated mice. Our findings may provide new drug targets for bladder inflammation and inflammatory pain in CP-induced hemorrhagic cystitis.