Polygonum capitatum (PC), known as "Tou Hua Liao" (Chinese name), is an essential source of Hmong medicinal plants, which has been used for treating various human diseases. This study examined whether PC has lipid-lowering and anti-atherosclerotic effects and explored the underlying mechanisms. We focused on PC's influence on gut microbiota-derived metabolites. First, we analyzed animal-derived serum containing PC components and the botanical compounds of PC by UPLC-MS/MS to identify potential bioactive constituents. Second, we treated high-fat diet-fed hamsters with PC to determine whether the treatment improved plasma lipids and attenuated atherosclerosis progression. We then assessed PC's effects on the gut microbiota by 16S rDNA sequencing and performed fecal microbiota transplantation in hamster models. Finally, we used human umbilical vein endothelial cells (HUVECs) to probe molecular mechanisms by which PC might inhibit oxidative stress and apoptosis. In a diet-induced atherosclerotic hamster model, PC treatment reduced atherosclerosis by decreasing lipid accumulation, oxidative stress, and apoptosis, and it restored gut microbiota balance while markedly lowering the abundance of TMAO-producing bacteria. PC also exerted antioxidant and anti-apoptotic effects and inhibited endothelial apoptosis via an MCPIP1-dependent mechanism. Together, these results indicate that PC suppresses atherosclerosis through two likely pathways: reduction of gut microbiota-derived TMAO production and inhibition of oxidative stress-driven endothelial apoptosis. Network pharmacology analysis of PC-specific blood-absorbed components supports these findings.

Natural products with vasodilatory properties are increasingly recognized for treating hypertension, angina, and heart failure owing to their efficacy, accessibility, and favorable safety profiles, rendering them viable therapeutic alternatives. Following a systematic search of the NCBI PubMed and CNKI databases, 227 natural compounds with potent vasodilatory activity were identified. This review delineates the vasodilatory effects of major phytochemical classes—specifically flavonoids, saponins, phenols, and alkaloids—and evaluates preclinical evidence supporting their therapeutic application. Furthermore, potential vasodilatory mechanisms are elucidated, encompassing endothelium-dependent regulation of smooth muscle tone, fluid homeostasis, oxidative stress mitigation, and antagonism of the renin-angiotensin-aldosterone system. These mechanisms clarify the pharmacological basis of natural vasodilators, offering researchers and clinicians enhanced strategies for managing cardiovascular diseases.

Acute severe joint pain is a major symptom in gouty arthritis (GA), and its adequate treatment represents an unmet medical need. Mrgprb2, a specific mast cell receptor, has been implicated in the generation of chronic pain by mobilizing mast cell degranulation, yet its significance in GA pain and joint inflammation is still not well defined. Here, we found that Mrgprb2 was expressed in mouse synovial mast cells. In a murine model of GA, acute blockade or genetic deletion of Mrgprb2 significantly attenuated arthritis pain and hyperexcitability of joint nociceptors with significant reductions in innate immune cell recruitment in the synovium. Under naive conditions, activation of synovial Mrgprb2 was sufficient to excite peripheral terminals of joint nociceptors to induce acute joint hypernociception via the mobilization of mast cell degranulation. Additionally, the level of the neuropeptide substance P (SP) was elevated in the synovium of GA model mice. Using humanized MRGPRX2-knockin mice, we revealed that SP contributed to joint pain and inflammation by activating mast cells through Mrgprb2/MRGPRX2. These findings suggest that synovial mast cell-expressed Mrgprb2/MRGPRX2 merits consideration as a key neuroimmune player and a potential therapeutic target for treating GA pain and joint inflammation.

Salidroside is a potential therapeutic agent for myocardial infarction (MI), exerting therapeutic effects on macrophage migration inhibitory factor (MIF)-regulated mitochondrial quality control. Our aim was to explore the mechanism through which the MIF pathway regulates salidroside-mediated resistance to hypoxia-induced cardiomyocyte apoptosis. Ligation surgery of the left anterior descending branch of the coronary artery was employed to establish a myocardial infarction mouse model. Salidroside at low and high doses was administered to the mice for 4 weeks after the surgery. Cardiac function was evaluated via echocardiography. Morphological changes, apoptosis, and mitochondrial damage in the myocardium were examined. For the cell experiments, cardiomyocytes were treated with salidroside under oxygen‒glucose deprivation (OGD) conditions and were either treated with recombinant MIF (rMIF) or transfected with Mif-siRNA. Subsequently, mitochondrial quality control and apoptosis were assessed. Salidroside enhanced mitochondrial quality control in MI model mice, mitigated apoptosis and improved cardiac dysfunction. Transmission electron microscopy indicated that there were fewer damaged mitochondria in the salidroside-treated mice compared with the control mice. MIF and downstream mitochondrial quality control pathways were activated in the mice treated with salidroside. Consistently, the cell experiments demonstrated that salidroside and rMIF alleviated apoptosis, improved impaired mitochondrial quality control in OGD-induced cells and activated MIF signaling in OGD-induced cells. However, these effects of salidroside were partially blocked by Mif-siRNA transfection. Salidroside alleviated myocardial apoptosis and ameliorated cardiac dysfunction in MI model mice through the MIF pathway and downstream mitochondrial quality control.

Lipoprotein lipase (LPL) hydrolyzes circulating triglycerides (TGs), releasing fatty acids (FA) and promoting lipid storage in white adipose tissue (WAT). However, the mechanisms regulating adipose LPL and its relationship with the development of hypertriglyceridemia are largely unknown. WAT from obese humans exhibited high PAR2 expression, which was inversely correlated with the LPL gene. Decreased LPL expression was also inversely correlated with elevated plasma TG levels, suggesting that adipose PAR2 might regulate hypertriglyceridemia by downregulating LPL. In mice, aging and high palmitic acid diet (PD) increased PAR2 expression in WAT, which was associated with a high level of macrophage migration inhibitory factor (MIF). MIF downregulated LPL expression and activity in adipocytes by binding with CXCR2/4 receptors and inhibiting Akt phosphorylation. In a MIF overexpression model, high-circulating MIF levels suppressed adipose LPL, and this suppression was associated with increased plasma TGs but not FA. Following PD feeding, adipose LPL expression and activity were significantly reduced, and this reduction was reversed in Par2-/- mice. Recombinant MIF infusion restored high plasma MIF levels in Par2-/- mice, and the levels decreased LPL and attenuated adipocyte lipid storage, leading to hypertriglyceridemia. These data collectively suggest that downregulation of adipose LPL by PAR2/MIF may contribute to the development of hypertriglyceridemia.

Metabolic and endocrine dysfunction of white adipose tissue (WAT) is linked to inflammation, which has been considered a key mechanism of insulin resistance (IR). However, recent studies revealed non-inflammatory mechanisms of IR in WAT, which may trigger inflammation and could be developed as a novel strategy to counteract IR.

Atypical antipsychotics (AAPs) are primary medications for schizophrenia (SZ). However, their use is frequently associated with the development of adverse metabolic effects, and the mechanisms behind these negative effects remain inadequately elucidated. To investigate the role of macrophage migration inhibitory factor (MIF) in regulating antipsychotic-induced metabolic abnormalities, between 2017 and 2020, a cross-sectional study was conducted, involving 142 healthy individuals and 388 SZ patients undergoing treatment with either typical antipsychotic (TAP) or AAP medications. Symptoms of SZ patients were evaluated using the Positive and Negative Syndrome Scale (PANSS), and measurements of metabolic indices and plasma MIF levels were performed on all individuals. A significant increase in plasma MIF levels was observed in groups receiving five major AAP monotherapies in comparison to healthy controls (all p < 0.0001). There was no such increase shown in the group receiving TAP treatment (p > 0.05). Elevated plasma MIF levels displayed a notable correlation with insulin resistance (β = 0.024, p = 0.020), as well as with the levels of triglycerides (β = 0.019, p = 0.001) and total cholesterol (β = 0.012, p = 0.038) in the groups receiving AAPs. However, while the TAP group also displayed certain metabolic dysfunction compared to healthy controls, no significant association was evident with plasma MIF levels (all p > 0.05). In conclusion, plasma MIF levels exhibit a distinctive correlation with metabolic abnormalities triggered by AAPs. Hence, there is potential for further development of MIF as a distinctive marker for monitoring adverse metabolic effects induced by AAPs in clinical settings.

Metabolic abnormalities affect clinical recovery and long-term survival in patients with acute myocardial infarction, but the underlying mechanisms remain unclear. D-dopachrome tautomerase (DDT) in cardiomyocytes protects the heart from injury during hypoxia-ischemia in mice. Our present study found that metabolic dysfunction induced by high fat diet (HFD) was associated with reduced cardiac DDT expression and aggravated cardiac injury following ischemia-reperfusion. Supplementation of DDT prior to ischemia decreased post-ischemic injury in these hearts, suggesting that DDT reduction is an important mechanism regulating post-ischemic cardiac injury associated with metabolic dysfunction. Among all the major fatty acid species in HFD, high palmitic acid (PA) triggered the expression and activation of protease activated receptor 2 (PAR2), which upregulated the transcriptional factors, CREB1 and FOXO1 leading to downregulation of DDT expression in the heart. PAR2 stimulated ERK phosphorylation, thereby upregulating CREB1 phosphorylation. Attenuation of CREB by siRNA significantly decreased FOXO1 expression and accumulation in the nucleus, thereby reducing cardiac DDT expression. Accordingly, PAR2 deficient mice exhibited normal ERK and CREB phosphorylation and DDT levels in the heart following HFD and reversed cardiac function recovery following reperfusion. Overall, our data reveal for the first time a novel role for DDT in mediating myocardial ischemia-reperfusion injury associated with metabolic dysfunction. Disclosure L. Li: None. Y. Qi: None. N. Cui: None. L. Leng: None. H. Wu: None. R. Bucala: None. D. Qi: None. Funding This study was supported by National Sciences and Engineering Research Council of Canada (NSERC: RGPIN-2017-04542) and Canadian Institutes of Health Research (CIHR Project Grant: PJT-156116).

Attenuation of adipose hormone sensitive lipase (HSL) may impair lipolysis and exacerbate obesity. We investigate the role of cytokine, macrophage migration inhibitory factor (MIF) in regulating adipose HSL and adipocyte hypertrophy. Extracellular MIF downregulates HSL in an autocrine fashion, by activating the AMPK/JNK signaling pathway upon binding to its membrane receptor, CD74. WT mice fed high fat diet (HFD), as well as mice overexpressing MIF, both had high circulating MIF levels and showed suppression of HSL during the development of obesity. Blocking the extracellular action of MIF by a neutralizing MIF antibody significantly reduced obesity in HFD mice. Interestingly, intracellular MIF binds with COP9 signalosome subunit 5 (Csn5) and JNK, which leads to an opposing effect to inhibit JNK phosphorylation. With global MIF deletion, adipocyte JNK phosphorylation increased, resulting in decreased HSL expression, suggesting that the loss of MIF's intracellular inhibitory action on JNK was dominant in Mif−/− mice. Adipose tissue from Mif−/− mice also exhibited higher Akt and lower PKA phosphorylation following HFD feeding compared with WT, which may contribute to the downregulation of HSL activation during more severe obesity. Both intracellular and extracellular MIF have opposing effects to regulate HSL, but extracellular actions predominate to downregulate HSL and exacerbate the development of obesity during HFD.

Nonalcoholic fatty liver disease (NAFLD) is associated with metabolic dysfunctions, such as obesity. Macrophage migration inhibitory factor (MIF), a pro-cytokine, was also identified to regulate NAFLD, but the molecular mechanisms remain unclear. We presently indicated that MIF has a non-inflammatory effect on triggering NAFLD through upregulating its cell membrane receptor, CD74. MIF increased CD74 protein rather than gene expression in liver cells in a time-dependent manner. That was not associated with any changes in the expression of pro-inflammatory factors, such as TNF-α, IL-6 and IL-1β. In a MIF overexpressed animal model (Mif lung Tg), high circulating MIF levels increased hepatic CD74 proteins but not genes in the absence of inflammation in the liver. High fat diet also increased circulating MIF levels leading to an upregulation of hepatic CD74. All these animal models with high circulating MIF and hepatic CD74 were accompanied with steatosis and fibrosis in the liver. These alterations could be reversed by either MIF neutralization or MIF knockout. Caspase 4 facilitates the degradation of CD74. MIF endocytosis inhibited caspase 4 cleavage and activation. Thus, inhibition of MIF upregulated cleaved caspase 4 leading to a degradation in CD74. Overall, our findings indicate that MIF stabilizes CD74 through suppressing caspase 4 and this may be an important mechanism in regulating NAFLD in the absence of inflammation. Disclosure L. Chen: None. L. Li: None. Y. Huang: None. X. Chen: None. Y. Qi: None. H. Tong: None. H. Wu: None. D. Qi: None. Funding Canadian Institutes of Health Research (PJT156116); Research and Development Corporation; National Sciences and Engineering Research Council of Canada (RGPIN-2017-04542); National Institutes of Health (AR-078334); China Scholarship Council (to L.C., Y.H., L.L.)

While insulin resistance (IR) is associated with inflammation in white adipose tissue, we report a non-inflammatory adipose mechanism of high fat-induced IR mediated by loss of Pref-1. Pref-1, released from adipose Pref-1+ cells with characteristics of M2 macrophages, endothelial cells or progenitors, inhibits MIF release from both Pref-1+ cells and adipocytes by binding with integrin β1 and inhibiting the mobilization of p115. High palmitic acid induces PAR2 expression in Pref-1+ cells, downregulating Pref-1 expression and release in an AMPK-dependent manner. The loss of Pref-1 increases adipose MIF secretion contributing to non-inflammatory IR in obesity. Treatment with Pref-1 blunts the increase in circulating plasma MIF levels and subsequent IR induced by a high palmitic acid diet. Thus, high levels of fatty acids suppress Pref-1 expression and secretion, through increased activation of PAR2, resulting in an increase in MIF secretion and a non-inflammatory adipose mechanism of IR.

Switching to normal diet (ND) is the regular therapy for high-fat diet (HFD)-induced nonalcoholic fatty liver disease (NAFLD). Intermittent fasting (IF) is a unique treatment which may exhibits better therapeutic efficacy. Thus, we aim to investigate the therapeutic effects of these treatments and exploring the mechanisms. In the present study, NAFLD mouse model was induced by a 10-week HFD. Thereafter, mice adopted continued HFD, ND, or IF for the next 12 weeks. Finally, the liver was then harvested to assess lipid deposition, lipid metabolism, apoptosis, and autophagy, while blood was collected to determine blood glucose and insulin. The results showed that IF and ND treatment improved lipid deposition and metabolic disorder of NAFLD mice; the increasing body weight, liver weight, and HOMA-IR index of HFD mice were also alleviated by IF and ND. Furthermore, IF and ND treatment activated the macrophage migration inhibitory factor (MIF)/AMPK pathway and regulated its downstream autophagy and apoptosis. However, the efficacy of IF was better than ND. Both IF and ND activates MIF signaling and alleviate the lipotoxicity of NAFLD while IF therapy is more effective than ND. The different MIF up-regulation might be the underlying mechanism of why IF benefits more than ND.

Olanzapine is one of the first-line antipsychotic medications but it usually induces metabolic side effects, characterized by obesity. We previously indicated that olanzapine leads to hyperphagia through the effects of a proinflammatory cytokine, macrophage migration inhibitory factor (MIF) in the hypothalamus. However, whether olanzapine's upregulated peripheral MIF could affect the central mechanism is currently unknown. Our present study found that olanzapine increases ectopic expression of dopamine receptor 1 (DRD1) in adipocytes which relatively upregulates MIF expression and release through a PKA/CREB signaling pathway. In global MIF knockout mice, MIF accumulation appears in the hypothalamus following peripheral injection of recombinant MIF proteins, suggesting that peripheral MIF indeed travels to the hypothalamus. Mif Lung Tg mice (MIF overexpression in the lung) with increased circulating MIF levels had hyperphagia and activation of the CaMKKβ/AMPK/AgRP signaling pathway in the hypothalamus. Overall, our study for the first time proved that adipose-derived MIF is a crucial factor in regulating metabolic side effects induced by olanzapine. Disclosure X.Chen: None. Y.Huang: None. Y.Qi: None. L.Chen: None. L.Li: None. P.Gao: None. D.Cui: None. D.Qi: None. Funding National Sciences and Engineering Research Council of Canada (RGPIN-2017-04542); Canadian Institutes of Health Research (PJT-156116); China Scholarship Council (202106230212)

Lipoprotein lipase (LPL) is a key enzyme that hydrolyzes circulating triglycerides to release fatty acid (FA). In adipose tissue, LPL is required for lipid storage. However, it is currently unknown whether alteration of LPL in white adipose tissue (WAT) contributes to the development of hypertriglyceridemia. Our present study indicated that WAT isolated from human obese patients have increased expression of PAR2 which is negatively associated with LPL gene. The reduced LPL expression is also negatively correlated with increased plasma TG levels, suggesting that adipose PAR2 may modulate hyperlipidemia through downregulating LPL. In mice, aging and high palmitic oil diet significantly increased PAR2 expression in adipose tissue which was associated with high plasma MIF levels. PAR2 deficiency attenuates the rise of MIF, suggesting a key role of PAR2 in regulating adipose MIF release. MIF reduced LPL expression and activity in adipocytes. In a MIF overexpressed animal model (Mif lung Tg), high circulating MIF levels inhibited adipose LPL which was associated with increased plasma triglyceride but not fatty acid. Following high palmitic oil diet feeding, adipose LPL expression and activity were also reduced, and this reduction was reversed in PAR2 knockout mice. Interestingly, PAR2 mediated LPL in adipose tissue regulates hypertriglyceridemia through controlling adipocyte lipid storage. In Par2-/- mice, recombinant MIF perfusion recovered high plasma MIF levels, which decreased LPL and attenuated adipocyte lipid storage leading to hypertriglyceridemia. These data together suggest that the downregulation of adipose LPL by PAR2/MIF is an important mechanism for the development of hypertriglyceridemia. Y.Huang: None. L.Li: None. L.Chen: None. X.Chen: None. P.Gao: None. Y.Qi: None. D.Qi: None. Canadian Institutes of Health Research (PJT156116)

Pro-inflammatory cytokines are responsible for initiating an effective defense against exogenous pathogens, and their regulation has a vital role in maintaining physiological homeostasis. The involvement of pro-inflammatory cytokines in pathological conditions have been explored in great detail, however, studies investigating metabolic pathways associated with these cytokines under normal homeostatic conditions are scarce. The aim of the current study was to identify metabolites and metabolic pathways associated with circulating pro-inflammatory cytokines under homeostatic conditions using a metabolomics approach. The study participants (n = 133) were derived from the Newfoundland Osteoarthritis Study (NFOAS) and the Complex Diseases in the Newfoundland population: Environment and Genetics (CODING) study. Plasma concentrations of cytokines including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), and macrophage migration inhibitory factor (MIF) were assessed by enzyme-linked immunosorbent assay. Targeted metabolomic profiling on fasting plasma samples was performed using Biocrates MxP® Quant 500 kit which measures a total of 630 metabolites. Associations between natural log-transformed metabolite concentrations and metabolite sums/ratios and cytokine levels were assessed using linear regression with adjustment for age, sex, body mass index (BMI), and osteoarthritis status. Seven metabolites and 11 metabolite sums/ratios were found to be significantly associated with TNF-α, IL-1β, and MIF (all p ≤ 5.13 × 10− 5) after controlling multiple testing with Bonferroni method, indicating the association between glutathione (GSH), polyamine, and lysophosphatidylcholine (lysoPC) synthesis pathways and these pro-inflammatory cytokines. GSH, polyamine, and lysoPC synthesis pathways were positively associated with circulating TNF-α, IL-1β, and MIF levels under homeostatic conditions.

Metformin is widely used to surmount insulin resistance (IR) and type 2 diabetes. Accumulating evidence suggests that metformin may improve IR through regulating gut microbiota and bile acids. However, the underlying mechanisms remain unclear. Our metabolomic analysis showed that metformin significantly increased the accumulation of tauroursodeoxycholic acid (TUDCA) in intestine and liver from high-fat diet (HFD)-induced IR mice. TUDCA also alleviated IR, and reduced oxidative stress and intestinal inflammation in ob/ob mice. TUDCA blocked KEAP1 to bind with Nrf2, resulting in Nrf2 translocation into nuclear and initiating the transcription of antioxidant genes, which eventually reduced intracellular ROS accumulation and improved insulin signaling. Analysis of gut microbiota further revealed that metformin reduced the relative abundance of Bifidobacterium, which produces bile salt hydrolase (BSH). The reduction in BSH was probably crucial for the accumulation of TUDCA. Metformin also increased the proportion of Akkermanisia muciniphlia in gut microbiota of ob/ob mice via TUDCA. These beneficial effects of metformin in remodeling gut microbiota, reducing oxidative stress and improving insulin sensitivity were partly due to the accumulation of TUDCA, suggesting that TUDCA may be a potential therapy for metabolic syndrome.

Obesity is a global pandemic, but there is yet no effective measure to control it. Recent metabolomics studies have identified a signature of altered amino acid profiles to be associated with obesity, but it is unclear whether these findings have actionable clinical potential. The aims of this study were to reveal the metabolic alterations of obesity and to explore potential strategies to mitigate obesity. We performed targeted metabolomic profiling of the plasma/serum samples collected from six independent cohorts and conducted an individual data meta-analysis of metabolomics for body mass index (BMI) and obesity. Based on the findings, we hypothesized that restriction of branched-chain amino acids (BCAAs), phenylalanine, or tryptophan may prevent obesity and tested our hypothesis in a dietary restriction trial with eight groups of 4-week-old male C57BL/6J mice (n = 5/group) on eight different types of diets, respectively, for 16 weeks. A total of 3397 individuals were included in the meta-analysis. The mean BMI was 30.7 ± 6.1 kg/m2, and 49% of participants were obese. Fifty-eight metabolites were associated with BMI and obesity (all p ≤ 2.58 × 10−4), linked to alterations of the BCAA, phenylalanine, tryptophan, and phospholipid metabolic pathways. The restriction of BCAAs within a high-fat diet (HFD) maintained the mice’s weight, fat and lean volume, subcutaneous and visceral adipose tissue weight, and serum glucose and insulin at levels similar to those in the standard chow group, and prevented obesity, adipocyte hypertrophy, adipose inflammation, and insulin resistance induced by HFD. Our data suggest that four metabolic pathways, BCAA, phenylalanine, tryptophan, and phospholipid metabolic pathways, are altered in obesity and restriction of BCAAs within a HFD can prevent the development of obesity and insulin resistance in mice, providing a promising strategy to potentially mitigate diet-induced obesity.

Inflammation is involved in the pathogenesis of psychiatric disorders. Many previous studies have defined the important roles of inflammatory factors in the pathogenesis, diagnosis, and treatment outcomes of psychiatric disorders. Macrophage migration inhibitory factor (MIF), a pro-inflammatory factor, has been gradually recognized to be involved in the development of neurological diseases in recent years. Our current review focuses on discussing the potential beneficial and detrimental roles of MIF in psychiatric disorders. We will provide new mechanistic insights for the development of potential diagnostic and therapeutic biomarkers based on MIF for psychiatric diseases.

Musculoskeletal pain often occurs simultaneously at multiple anatomical sites. The aim of the study was to identify metabolic biomarkers for multisite musculoskeletal pain (MSMP) by metabolomics with an extreme phenotype sampling strategy. The study participants (n = 610) were derived from the Newfoundland Osteoarthritis Study. Musculoskeletal pain was assessed using a self-reported pain questionnaire where painful sites were circled on a manikin by participants and the total number of painful sites were calculated. Targeted metabolomic profiling on fasting plasma samples was performed using the Biocrates AbsoluteIDQ p180 kit. Plasma cytokine concentrations including tumor necrosis factor-alpha, interleukin-6, interleukin-1 beta, and macrophage migration inhibitory factor were assessed by enzyme-linked immunosorbent assay. Data on blood cholesterol profiles were retrieved from participants' medical records. Demographic, anthropological, and clinical information was self-reported. The number of reported painful sites ranged between 0 and 21. Two hundred and five participants were included in the analysis comprising 83 who had >= 7 painful sites and 122 who had <= 1 painful site. Women and younger people were more likely to have MSMP (P <= 0.02). Multisite musculoskeletal pain was associated with a higher risk of having incontinence, worse functional status and longer period of pain, and higher levels of low-density lipoprotein and non-high-density lipoprotein cholesterol (all P <= 0.03). Among the 186 metabolites measured, 2 lysophosphatidylcholines, 1 with 26 carbons with no double bond and 1 with 28 carbons with 1 double bond, were significantly and positively associated with MSMP after adjusting for multiple testing with the Bonferroni method (P <= 0.0001) and could be considered as novel metabolic markers for MSMP.