Mendelian randomization analyses reveal no genetic causal effects of major adipokines on systemic lupus erythematosus.

Epidemiological studies have shown that the levels of serum adipokine such as leptin and resistin are associated with the risk of developing systemic lupus erythematosus (SLE). Nevertheless, whether either leptin or resistin has causal impacts on the risk of SLE is still unknown. In this study, two-sample univariable MR analyses and multivariable MR analysis were performed to explore the causal relationships between adipokines and SLE. Additionally, the potential causal effects of SLE on major adipokines were evaluated using reverse MR analyses. The results of inverse-variance weighted (IVW), weighted median, weighted mode and MR‒Egger methods concordantly supported that major adipokines have no causal effects on the risk of SLE. In the multivariable MR IVW analysis with leptin and resistin as covariates, neither leptin (odds ratio (OR) = 3.093, P = 0.067) nor resistin (OR = 0.477, P = 0.311) was identified as an independent risk factor for SLE, which is in line with the univariable MR results. In conclusion, our analyses revealed no evidence to support that these three major adipokines are risk factors for SLE.

Macrophage-derived human resistin promotes perivascular adipose tissue dysfunction in experimental inflammatory arthritis.

Cardiovascular disease (CVD) is the leading cause of death in rheumatoid arthritis (RA). Resistin is an adipokine that induces adipose tissue inflammation and activation of monocytes/macrophages via adenylate cyclase-associated protein-1 (CAP1). Resistin levels are increased in RA and might cause perivascular adipose tissue (PVAT) dysfunction, leading to vascular damage and CVD. This study aimed to investigate the role of resistin in promoting PVAT dysfunction by increasing local macrophage and inflammatory cytokines content in antigen-induced arthritis (AIA). Resistin pharmacological effects were assessed by using C57Bl/6J wild-type (WT) mice, humanized resistin mice expressing human resistin in monocytes-macrophages (hRTN+/-/-), and resistin knockout mice (RTN-/-) with AIA and respective controls. We investigated AIA disease activity and functional, cellular, and molecular parameters of the PVAT. Resistin did not contribute to AIA disease activity and its concentrations were augmented in the PVAT and plasma of WT AIA and hRTN+/-/- AIA animals. In vitro exposure of murine arteries to resistin impaired vascular function by decreasing the anti-contractile effect of PVAT. WT AIA mice and hRTN+/-/- AIA mice exhibited PVAT dysfunction and knockdown of resistin prevented it. Macrophage-derived cytokines, markers of types 1 and 2 macrophages, and CAP1 expression were increased in the PVAT of resistin humanized mice with AIA, but not in knockout mice for resistin. This study reveals that macrophage-derived resistin promotes PVAT inflammation and dysfunction regardless of AIA disease activity. Resistin might represent a translational target to reduce RA-driven vascular dysfunction and CVD.

GHRL, LEP, LEPR genes polymorphism and their association with the metabolic syndrome in the Ukrainian population.

Objective. Many conflicting results have been obtained in the study of leptin (LEP) and leptin receptor (LEPR) gene variants that are associated with the obesity and diabetes possibly due to differences in the study populations. The aim of this study was to evaluate changes in the metabolic hormones (leptin, ghrelin, adiponectin, resistin) levels in the blood of obese patients in relation to the GHRL (rs696217), LEP (rs7799039), LEPR (rs1137100, rs1137101, rs1805094) polymorphism in Ukrainian population. Methods. The study involved 53 obesity cases and 48 non-obesity subjects (controls). The GHRL, LEP, and LEPR genes polymorphism (rs696217, rs7799039, rs1137100, rs1137101, rs1805094) was genotyped using a TaqMan real-time polymerase chain reaction method. Blood hormones (leptin, ghrelin, adiponectin, resistin) were determined with commercially available kits using a Multiskan FC analyzer. Results. The study of the effect of genotypes of the GHRL (rs696217), LEP (rs7799039), and LEPR (rs1137100, rs1805094) polymorphisms on the level of metabolic hormones (leptin, ghrelin, adiponectin, resistin) in the blood of obese patients did not show reliably significant results. Thus, the presence of the LEPR genes (rs1137101) polymorphism in the Ukrainian population indicates an increased risk of the metabolic syndrome development regardless of the homozygous or heterozygous genotype (genotypes AA, AG, GG). Conclusions. We established a significant effect of the presence of the A allele and G allele of the LEPR gene polymorphism (rs1137101) on the level of leptin, ghrelin, adiponectin, and resistin in the serum of patients diagnosed with the metabolic syndrome in the Ukrainian population.

Integrated Analyses of Single-Cell Transcriptome and Mendelian Randomization Reveal the Protective Role of Resistin in Sepsis Survival in Intensive Care Unit.

The high morbidity and mortality rates associated with sepsis highlight the challenges of finding specific remedies for this condition in the intensive care unit (ICU). This study aimed to explore the differentially expressed genes (DEGs) specific to cell types in sepsis and investigate the role of resistin in the survival of sepsis patients through Mendelian randomization (MR) analyses. We used single-cell and bulk transcriptome data to identify cell type-specific DEGs between sepsis and healthy controls. MR analyses were then conducted to investigate the causal relationships between resistin (one of the identified DEGs) levels and the survival of sepsis patients. Additionally, we utilized meQTL (methylation quantitative trait loci) to identify cytosine-phosphate-guanine (CpG) sites that may directly affect sepsis. We identified 560 cell type-specific DEGs between sepsis and healthy controls. Notably, we observed the upregulation of resistin levels in macrophages during sepsis. In bulk transcriptome, RETN is also upregulated in sepsis samples compared with healthy controls. MR analyses revealed a negative association existed between the expression of resistin, at both gene and protein levels, and the mortality or severity of sepsis patients in ICU. Moreover, there were no associations observed between resistin levels and death or organ failure due to other causes. We also identified three methylation CpG sites, located in RETN or its promoter region-cg06633066, cg22322184, and cg02346997-that directly affected both resistin protein levels and sepsis death in the ICU. Our findings suggest that resistin may provide feasible protection for sepsis patients, particularly those with severe cases, without serious side effects. Therefore, resistin could be a potential drug candidate for sepsis treatment. Additionally, we identified two CpG sites, cg06633066 and cg22322184, that were associated with RETN protein levels and sepsis death, providing novel insights into the underlying mechanisms of sepsis.

Study on the correlation between gene polymorphisms of adiponectin and resistin levels and abdominal aortic aneurysm.

OBJECTIVES: Abdominal Aortic Aneurysm (AAA) is a complex disease with both genetic and environmental risk factors. This study aimed to examine the potential association of the +276G/T and -420C>G polymorphisms in the resistin gene with AAA susceptibility and progression. METHOD: We performed a retrospective study involving AAA patients and healthy controls, assessing the distribution of the +276G/T and -420C>G genotypes in both groups. Hardy-Weinberg equilibrium was assessed for both polymorphisms. Logistic regression was used to explore the influence of these genotypes on AAA occurrence and progression, adjusting for relevant confounders. RESULTS: The distribution of +276G/T polymorphism did not significantly differ between AAA patients and controls. Conversely, a significant difference was observed in the genotype distribution of -420C>G polymorphism between the two groups. The CC genotype and CC/CG genotypes of -420C>G polymorphism were found to be associated with an increased risk and progression of AAA. CONCLUSIONS: The -420C>G polymorphism, particularly the CC genotype and CC/CG genotypes, might play a substantial role in AAA susceptibility and progression. The present findings underscore the need for further investigations to confirm these associations and fully elucidate the role of the resistin gene in AAA.

Genetically determined circulating resistin concentrations and risk of colorectal cancer: a two-sample Mendelian randomization study.

PURPOSE: Resistin, a novel pro-inflammatory protein implicated in inflammatory processes, has been suggested to play a role in colorectal development. However, evidence from observational studies has been inconsistent. Mendelian randomization may be a complementary method to examine this association. METHODS: We conducted a two-sample Mendelian randomization to estimate the association between genetically determined circulating resistin concentrations and risk of colorectal cancer (CRC). Protein quantitative trait loci (pQTLs) from the SCALLOP consortium were used as instrumental variables (IVs) for resistin. CRC genetic summary data was obtained from GECCO/CORECT/CCFR (the Genetics and Epidemiology of Colorectal Cancer Consortium, Colorectal Cancer Transdisciplinary Study, and Colon Cancer Family Registry), and FinnGen (Finland Biobank). The inverse variance weighted method (IVW) was applied in the main analysis, and other robust methods were used as sensitivity analyses. Estimates for the association from the two data sources were then pooled using a meta-analysis approach. RESULTS: Thirteen pQTLs were identified as IVs explaining together 7.80% of interindividual variation in circulating resistin concentrations. Based on MR analyses, genetically determined circulating resistin concentrations were not associated with incident CRC (pooled-IVW-OR per standard deviation of resistin, 1.01; 95% CI 0.96, 1.06; p = 0.67. Restricting the analyses to using IVs within or proximal to the resistin-encoding gene (cis-IVs), or to IVs located elsewhere in the genome (trans-IVs) provided similar results. The association was not altered when stratified by sex or CRC subsites. CONCLUSIONS: We found no evidence of a relationship between genetically determined circulating resistin concentrations and risk of CRC.

Genetic Association of Circulating Adipokines with Risk of Idiopathic Pulmonary Fibrosis: A Two-Sample Mendelian Randomization Study.

PURPOSE: The causal relationships between circulating adipokines and idiopathic pulmonary fibrosis (IPF) are yet to be established. We performed a two-sample Mendelian randomization (MR) study to investigate the causal roles of adipokines on IPF risk. METHODS: We analyzed the summary data from genome-wide association studies (GWAS), including adiponectin, leptin, resistin and monocyte chemoattractant protein-1 (MCP-1) and IPF. The inverse-variance weighted (IVW) method was considered as the major method and the MR-Egger, weighted median, simple mode and weighted mode were utilized as complementary methods. We also performed the sensitivity analyses, including heterogeneity test, horizontal pleiotropy test and leave-one-out analysis. RESULTS: The selected number of single nucleotide polymorphisms (SNPs) was 13 for adiponectin, 6 for leptin,12 for resistin, and 6 for MCP-1, respectively. The results showed a causal effect of the circulating adiponectin levels on the risk of IPF (OR 0.645, 95% CI 0.457-0.911, P = 0.013). However, we did not observe significant associations of genetic changes in serum leptin (OR 1.018, 95% CI 0.442-2.346, P = 0.967), resistin (OR 1.002, 95% CI 0.712-1.408, P = 0.993), and MCP-1 (OR 1.358, 95% CI 0.891-2.068, P = 0.155) with risk of developing IPF. There was no evidence of heterogeneity or horizontal pleiotropy. The sensitivity analyses confirmed that our results were stable and reliable. CONCLUSIONS: The increase in serum adiponectin was associated causally with a decreased risk of developing IPF. There is no evidence to support a causal association between leptin, resistin or MCP-1 with risk of IPF. Further studies are needed to confirm our findings.

Adipokines and risk of rheumatoid arthritis: A two-sample multivariable Mendelian randomisation study.

Adiponectin, leptin, and resistin are thought to be involved in the pathogenesis of rheumatoid arthritis (RA). However, the causal relationship between these adipokines and the risk for RA is unclear. We performed a range of two-sample Mendelian randomisation (MR) analyses to assess the causal effect of circulating adiponectin, leptin, and resistin on RA risk in European and East Asian individuals. Different sets of adiponectin-, leptin-, and resistin-related genetic variants were used as instruments for genetically determined adipokine levels. As body mass index (BMI) is a risk factor for RA and affects adipokine levels, multivariable MR was used to calculate the causal effect of each adipokine on RA risk taking BMI into account. Several MR analyses revealed no evidence of a causal relationship between circulating adiponectin, leptin, or resistin levels and RA risk in either Europeans or East Asians. Similarly, multivariable MR did not provide evidence of any causal effect of adiponectin, leptin, or resistin on RA risk when taking BMI into account. This MR study shows for the first time that genetically determined levels of adiponectin, leptin, or resistin do not have a direct causal effect on the risk of developing RA after adjustment for BMI.

RETN gene polymorphisms interact with alcohol dependence in association with depression.

BACKGROUND: Previous studies suggest that alcohol dependence is associated with increased risk of depression. The occurrence of depressive symptoms is related to polymorphisms in various genetic regions. This study aimed to investigate the interaction of RETN gene polymorphisms (rs1477341, rs3745368) with alcohol dependence on depressive symptoms in adult male during acute alcohol withdrawal. METHODS: A total of 429 male adults were recruited in this study. Alcohol dependence was assessed using the Michigan alcoholism screening test (MAST). Depression was assessed using the 20-item self-rating depression scale (SDS). Hierarchical regression analysis was used to evaluate the interaction between genes and alcohol dependence on depression. Region of significance (ROS) test was used to explain the interaction effect. The strong and weak forms of the differential susceptibility and diathesis models were used to determine which fits the data better. RESULTS: Our results showed that MAST scores were significantly positively associated with SDS scores (r = 0.23, p < 0.01) in alcohol-dependent patients during alcohol withdrawal. The interaction between genotype and alcohol dependence was significant (ß = -0.14, p < 0.05) in a strong diathesis-stress model. Susceptibility for depression symptoms was associated with alcohol dependence in RETN rs1477341 A carriers. Specifically, those that showed more alcohol dependence and the A allele of RETN rs1477341 exhibited more depression symptoms. However, RETN rs3745368 had no significant interaction with alcohol dependence. CONCLUSIONS: The A allele of RETN rs1477341 may correlate with susceptibility to depression symptoms in alcohol-dependent individuals during acute alcohol withdrawal.

Relation of resistin gene variants to resistin plasma levels and altered susceptibility to polycystic ovary syndrome: A case control study.

BACKGROUND: A role for resistin in the pathogenesis of polycystic ovarian syndrome (PCOS) and related features were described for various ethnicities. As its expression is partly inherited, a role for RETN polymorphisms in regulating resistin levels and PCOS risk was shown, but with varied results. AIM: To investigate the association of rs34124816 (-537A>C), rs1862513 (-420C>G), rs3219175 (-358G>A), rs3745367 (+299G>A), rs3745369 (+1263G>C), and rs1423096 (+4965C>T) RETN SNPs with PCOS. METHODS: Study subjects included 583 women with PCOS, and 713 eumenorrheic women serving as controls. Genotyping was done by real-time PCR. RESULTS: Higher minor allele frequency (MAF) of rs34124816, rs3219175, and rs3745369, and lower MAF of rs1862513 and rs1423096 were seen in PCOS cases. Reduced PCOS risk was found with rs3745367 minor-allele homozygotes and rs1423096 minor-allele homozygotes, while increased risk was linked with rs3745367 heterozygotes, and with rs3745369 heterozygotes and minor-allele homozygotes. While it did not reach statistical significance, serum resistin levels were elevated in PCOS cases than in control women and major-allele homozygotes of rs34124816 and rs1862513, and in rs1423096 minor-allele-containing carriers. Carriage of rs34124816 correlated positively with age and LH, whereas rs1862513 positively and rs3745367 negatively correlated with fasting glucose. Six-locus (rs34124816-rs1862513-rs3219175-rs3745367-rs3745369-rs1423096) haplotype analysis demonstrated a significant reduction in AGGGGG and a marked increase in AGGGCG haplotypes between cases and controls, thus assigning PCOS protective and susceptible nature to these haplotypes, respectively. CONCLUSIONS: This study is the first to document the contribution of rs34124816 and rs1423096 RETN variants to the risk of PCOS. The varied association of RETN gene variants with PCOS suggests an ethnic contribution of RETN association with PCOS.

The identification of a novel SNP in the resistin (RETN) gene associated with growth traits in Karakul and Awassi sheep.

Resistin is one of the most important adipocytokines in mammalian cells due to its involvement in insulin resistance, obesity, and autoimmune diseases. Resistin is encoded by RETN gene that is primarily expressed in adipose tissues. Mutations in this gene have been associated with several productive traits in animals. This study was conducted to assess the possible biomarker capacity of RETN by evaluating its association with growth traits in two economically important sheep in the Middle East. Genotyping was conducted using PCR-single strand conformation polymorphism (SSCP), and the polymorphism of RETN was associated with several growth traits for three months intervals starting from birth until one year of age. In a total of 190 Karakul sheep and 245 Awassi sheep, only one SNP (233A > C) was detected in the RETN gene. The identified novel SNP showed significant associations with all growth traits at the ages of six, nine, and twelve months. At the age of six months onward, lambs with AC and CC genotypes showed respectively lower body weight and length, chest and abdominal circumferences, and wither and rump heights than those with AA genotype. Due to the remarkable association between RETN;233A > C and lower growth traits, this genotype is suggested as a promising marker to assess growth traits in Karakul and Awassi sheep. This is the first study that demonstrated the importance of RETN as a possible tool for evaluating growth traits in two breeds of sheep with a possibility to be applied to other breeds via large-scale association analysis.

Impacts of RETN genetic polymorphism on breast cancer development in Beni-Suef females, Egypt.

Breast cancer is the most common cancer among females with increasing incidence and death rates. Resistin is pro-inflammatory molecule which shares in diverse cellular signaling pathways. This study aimed to evaluate resistin and RETN rs3219175 gene polymorphism and their relevance to diagnostic susceptibility, prognostic value, and genetic risk among Egyptian female patients with breast cancer. Eighty female patients with breast cancer were recruited from the Oncology Department, Faculty of Medicine, Beni-Suef University. Breast cancer staging and grading were determined. Eighty age-matched normal females participated as controls. Quantitative determination of serum resistin was assayed by an enzyme-linked immunosorbent assay (ELISA). RETN rs3219175 gene polymorphism was determined by real time polymerase chain reaction (RT-PCR) TaqMan allelic discrimination assay. Serum resistin showed statistically significantly higher level among females with breast cancer when compared to controls (p < 0.001). Resistin showed sensitivity of 80% and specificity of 67.5% at cut off value of 1.27 ng/mL for diagnosis of breast cancer (p =0.001). RETN rs3219175 gene polymorphism showed significantly higher frequency of AG, AA genotypes, and A allele among cases when compared to controls (p < 0.001). No statistical difference was found in resistin level or RETN rs3219175 gene polymorphism regarding tumor characteristics including size, lymph nodes or distant metastasis. Resistin showed significantly higher level among carriers of AG followed by AA genotypes and among A allele (p < 0.001). In conclusion, resistin could be proposed as a possible potential diagnostic marker and A allele of RETN rs3219175 gene might be suggested as a genetic risk allele among female patients with breast cancer.

Resistin G-A haplotype at SNP-420/-358 is associated with the latent sarcopenic obesity index in the toon genome study.

AIM/INTRODUCTION: Resistin, which induces insulin resistance, is mainly expressed in monocytes/macrophages in humans. We reported previously that serum resistin was highest in the G-A haplotype defined by resistin single nucleotide polymorphisms (SNPs) at -420 (rs1862513) and - 358 (rs3219175). As sarcopenic obesity is associated with insulin resistance, we aimed to examine whether serum resistin and its haplotypes were associated with sarcopenic obesity at a latent stage. MATERIALS AND METHODS: We cross-sectionally analyzed 567 community-dwelling Japanese participants attending annual medical check-ups in which the sarcopenic obesity index was evaluated. The age- and gender-matched normal glucose tolerance subjects with G-A homozygotes and those with C-G homozygotes were examined via RNA-sequencing and pathway analysis (each n = 3), and RT-PCR (each n = 8). RESULTS: In multivariate logistic regression analyses, the fourth quartile (Q4) of serum resistin and G-A homozygotes were both associated with the latent sarcopenic obesity index defined by a visceral fat area of ≥ 100 cm2 and grip strength Q1 after adjustment for age and gender, with or without other confounding factors. RNA sequencing and pathway analysis showed that tumor necrosis factor (TNF) was involved in the top five pathways in the whole blood cells of G-A homozygotes compared with C-G homozygotes. RT-PCR revealed that TNF mRNA was higher in G-A homozygotes than in C-G homozygotes. CONCLUSIONS: The G-A haplotype was associated with the latent sarcopenic obesity index defined by grip strength in the Japanese cohort, could be mediated by TNF-α.

Upregulation of peripheral blood mononuclear cells resistin gene expression in severe obstructive sleep apnea and obstructive sleep apnea with coexisting type 2 diabetes mellitus.

PURPOSE: Obstructive sleep apnea (OSA) is characterised by increased systemic inflammation, and is often accompanied with type 2 diabetes mellitus (T2DM) and cardiovascular disease. The aim of this investigation was to evaluate gene expression of resistin, its receptor CAP1 and CD36 as the indicators of the inflammatory changes in PBMCs in relation to the severity of OSA, and the presence of type 2 diabetes mellitus (T2DM) in OSA. METHODS: Severity of OSA was defined by the apnea/hypopnea index (AHI): AHI < 30: mild to moderate OSA (MM-OSA), AHI ≥ 30: severe OSA (S-OSA). Presence of T2DM was captured: OSA with T2DM (OSA + T2DM), OSA without T2DM (OSA-T2DM). PBMC resistin, CAP1, and CD36 mRNA were determined by real-time PCR. RESULTS: Resistin mRNA was significantly upregulated in S-OSA (N = 54) compared to the MM-OSA (N = 52, P = 0.043); CAP1 and CD36 mRNA levels did not differ between the groups (P = 0.302; P = 0.166, respectively). Resistin mRNA was significantly upregulated in OSA + T2DM (N = 29) compared to the OSA-T2DM (N = 77, P = 0.029); CAP1 and CD36 mRNA levels did not differ between the groups (P = 0.662; P = 0.108, respectively). AHI and T2DM were independent predictors of resistin mRNA above the 75th percentile (OR = 3.717 [1.152-11.991]; OR = 3.261 [1.000-10.630], P = 0.042 respectively). CONCLUSION: Resistin gene upregulation in S-OSA indicates its possible contribution to increased inflammation in S-OSA and makes it a possible marker of the disease severity. Resistin gene upregulation in OSA + T2DM suggests that a joint effect of these two comorbidities may have a major contribution to increased inflammation and complications that arise from this state.

Role of resistin (rs7139228) gene polymorphism with metabolic response after a hypocaloric mediterranean diet.

BACKGROUND: The SNP (rs7139228) of the RETN gene is a polymorphism that has been associated with metabolic disorder in subjects with obesity, and its effect on metabolic response after dietary intervention has not been evaluated. OBJECTIVE: Our objective was to analyse the effects of the polymorphism of the RETN gene rs7139228 on metabolic changes secondary to weight loss with a hypocaloric Mediterranean diet. DESIGN: 1000 obese Caucasian patients were evaluated. An anthropometric evaluation and a biochemical analysis were performed before and after 12 weeks of a hypocaloric Mediterranean diet. The statistical analysis was performed as a dominant model (GG vs GA+AA). RESULTS: Improvements in anthropometric parameters, leptin levels and systolic blood pressure were similar in both genotype groups. In non- A allele carriers, levels of resistin, insulin, HOMA-IR, triglycerides and C-reactive protein decreased. The improvements were statistically significant in this group; resistin (-1.3+0.1ng/dL: p=0.02), triglycerides (-22.9+4.9mg/dl: p=0.02), CRP (-2.7+0 0.4mg/dl: p=0.02), insulin -6.5+1.8 mIU/L: p=0.02) and HOMA-IR (-2.2+0.8: p=0, 03). In addition, insulin, HOMA-IR and resistin levels were higher in A allele carriers than in non-carriers. Finally, the prevalence of metabolic syndrome and hyperglycaemia were higher in A allele carriers, and these percentages only decreased after intervention in non-A allele carriers. CONCLUSION: The A rs7139228 allele is associated with a worse metabolic response (insulin, HOMA-IR, triglycerides and CRP) after weight loss with a hypocaloric Mediterranean diet. A non-significant decrease in the prevalence of metabolic syndrome and hyperglycaemia were detected in A allele carriers.

Resistin secreted by porcine alveolar macrophages leads to endothelial cell dysfunction during Haemophilus parasuis infection.

Haemophilus parasuis (H. parasuis) causes exudative inflammation, implying endothelial dysfunction during pathogen infection. However, so far, the molecular mechanism of endothelial dysfunction caused by H. parasuis has not been clarified. By using the transwell-based cell co-culture system, we demonstrate that knocking out resistin in porcine alveolar macrophages (PAMs) dramatically attenuated endothelial monolayer damage caused by H. parasuis. The resistin secreted by PAMs inhibited the expression of the tight junction proteins claudin-5 and occludin rather than the adherens junction protein VE-cadherin in co-cultured porcine aortic endothelial cells (PAECs). Furthermore, we demonstrate that resistin regulated claudin-5 and occludin expression and monolayer PAEC permeability in an LKB1/AMPK/mTOR pathway-dependent manner. Additionally, we reveal that the outer membrane lipoprotein gene lppA in H. parasuis induced resistin expression in PAMs, as deleting lppA reduced resistin expression in H. parasuis-infected PAMs, causing a significant change in LKB1/AMPK/mTOR pathway activity in co-cultured PAECs, thereby restoring tight junction protein levels and endothelial monolayer permeability. Thus, we postulate that the H. parasuis lppA gene enhances resistin production in PAMs, disrupting tight junctions in PAECs and causing endothelial barrier dysfunction. These findings elucidate the pathogenic mechanism of exudative inflammation caused by H. parasuis for the first time and provide a more profound angle of acute exudative inflammation caused by bacteria.

Relationship of resistin gene polymorphism (rs7139228) with resistin levels and metabolic syndrome risk in obese subjects.

Introduction: Background: despite the relationship of resistin with metabolic syndrome (MS), the relationship of the 5'UTR intron C/T variant SNP rs7139228 of the RETN gene with the presence of MS has not been evaluated. Objective: the objective of this study is to evaluate the influence of SNP rs7139228 of the RETN gene on circulating resistin levels, as well as on MS in obese subjects. Material and Methods: a Caucasian population of 1003 obese subjects was enrolled. An anthropometric evaluation (weight, waist circumference, fat mass), evaluation of nutritional intake, biochemical study (glucose, insulin, C-reactive protein, lipid profile, insulin, HOMA-IR, resistin) and rs7139228 genotype was carried out. Results: genotype distribution was: 852 subjects with GG (84.9 %), 147 subjects with GA (14.7 %) and 4 subjects with AA (0.4 %). The allelic frequency was G (0.92) and A (0.08). Serum levels of resistin (delta: 1.7 ± 0.2 ng/ml; p = 0.01), insulin (delta: 4.2 ± 0.4 IU/L; p = 0.01) and HOMA-IR (delta: 1.9 ± 0.2 units; p = 0.03) were higher in patients carrying the A allele than in non-carriers. The overall prevalence of MS was 48.1 %. A logistic regression analysis showed a high percentage of hyperglycemia (OR = 1.60, 95 % CI = 1.08-2.96; p = 0.02) and metabolic syndrome (OR = 1.33, 95 % CI = 1.07-3.39, p = 0.02) in carriers of the A allele after adjusting for resistin levels, sex, BMI and age. Conclusions: the A allele of the genetic variant rs7139228 is associated with higher levels of resistin, basal insulin, insulin resistance, and prevalence of metabolic syndrome in obese subjects.

Introducción: Antecedentes: a pesar de la relación de la resistina con el síndrome metabólico (SM), no se ha evaluado la relación del SNP rs7139228 con variante C/T del intrón 5´UTR del gen RETN con la presencia de SM. Objetivo: el objetivo del presente estudio es evaluar la influencia del SNP rs7139228 del gen RETN sobre las concentraciones de resistina circulante, así como sobre el SM en sujetos obesos. Material y métodos: se reclutó una población caucásica de 1003 sujetos obesos. En todos los sujetos se realizó un análisis antropométrico (peso, perímetro de cintura, masa grasa), una evaluación de la ingesta nutricional, un estudio bioquímico (glucosa, insulina, proteína C-reactiva, perfil lipídico, insulina, HOMA-IR, resistina) y una evaluación del genotipo rs7139228. Resultados: la distribución del genotipo fue la siguiente: 852 sujetos con GG (84,9 %), 147 sujetos con GA (14,7 %) y 4 sujetos con AA (0,4 %). La frecuencia alélica fue G (0,92) y C (0,08). Las concentraciones séricas de resistina (delta: 1,7 ± 0,2 ng/ml; p = 0,01), insulina (delta: 4,2 ± 0,4 UI/L; p = 0,01) y HOMA-IR (delta: 1,9 ± 0,2 unidades; p = 0,03) fueron mayores en los pacientes portadores del alelo A que en los no portadores. La prevalencia global del SM fue del 48,1 %. El análisis de regresión logística mostró un alto porcentaje de hiperglucemia (OR = 1,60, IC 95 % = 1,08-2,96; p = 0,02) y de síndrome metabólico (OR = 1,33, IC 95 % = 1,07-3,39; p = 0,02) en los portadores del alelo A después de ajustar las concentraciones de resistina, el sexo, el IMC y la edad. Conclusiones: el alelo A de la variante genética rs7139228 se asocia con mayores niveles de resistina, insulina basal, resistencia a la insulina y prevalencia de síndrome metabólico en sujetos obesos.

Demethylation of miR-299-5p by aerobic exercise relieves insulin resistance in the vascular endothelium by repressing resistin.

AIMS: Insulin resistance (IR) is a critical marker underlying type 2 diabetes mellitus (T2DM). Exercise is reported to prevent IR, yet the mechanism of which is complicated and largely unknown. Here, the study aimed to ascertain whether and how aerobic exercise mediates IR in T2DM. METHODS: An in vivo model of high-fat diet (HFD)-induced IR and an in vitro model of high-glucose-induced IR were constructed. RESULTS: Aerobic exercise training in mice led to attenuation of IR in the vascular endothelium. microRNA-299-5p (miR-299-5p) expression was deficient in T2MD, which could be restored by aerobic exercise through modulating the DNA methylation modification enzymes. The expression of miR-299-5p enhanced by aerobic exercise consequently resulted in ameliorating the IR in vivo. Furthermore, increased levels of nitric oxide (NO), reduced levels of Angiotensin II (Ang II), vascular endothelial growth factor (VEGF), tumor necrosis factor alpha (TNF-α), and interleukin-6 (IL-6) in response to miR-299-5p elevation suggested the anti-IR role of miR-299-5p in IR-cell model. Dual-luciferase reporter and ChIP assays identified that miR-299-5p could bind to resistin and hence repressed the resistin level. CONCLUSION: The key observation of the study is that aerobic exercise stimulates miR-299-5p-targeted resistin inhibition through demethylation, which underlies the mechanism of reducing IR.

Resistin impairs mitochondrial homeostasis via cyclase-associated protein 1-mediated fission, leading to obesity-induced metabolic diseases.

OBJECTIVE: One of the suggested mechanisms of obesity-induced insulin resistance is mitochondrial dysfunction in target tissues such as skeletal muscle. In our study, we examined whether resistin, an adipokine associated with obesity-mediated insulin resistance, induced metabolic disorders by impairing mitochondrial homeostasis. METHODS: The morphology and function of mitochondria of skeletal muscle were examined in resistin-knockout and humanized resistin mice that were subjected to high-fat diet for 3 months. Morphology was examined by transmission electron microscopy. Mitochondria bioenergetics of skeletal muscle were evaluated using a Seahorse XF96 analyzer. Human skeletal myoblasts were used for in vitro studies on signaling mechanisms in responses to resistin. RESULTS: A high-fat diet in humanized resistin mice increased fragmented and shorter mitochondria in the skeletal muscle, whereas resistin-knockout mice had healthy normal mitochondria. In vitro studies showed that human resistin treatment impaired mitochondrial homeostasis by inducing mitochondrial fission, leading to a decrease in ATP production and mitochondrial dysfunction. Induction of mitochondrial fission by resistin was accompanied by increased formation of mitochondria-associated ER membranes (MAM). At the same time, resistin induced up-regulation of the protein kinase A (PKA) pathway. This activation of PKA induced phosphorylation of Drp1 at serine 616, leading to Drp1 activation and subsequent induction of mitochondrial fission. The key molecule that mediated human resistin-induced mitochondrial fission was adenylyl cyclase-associated protein 1 (CAP1), which was reported as a bona fide receptor for human resistin. Moreover, our newly developed biomimetic selective blocking peptide could repress human resistin-mediated mitochondrial dysfunction. High-fat diet-fed mice showed lower exercise capacity and higher insulin resistance, which was prevented by a novel peptide to block the binding of resistin to CAP1 or in the CAP1-knockdown mice. CONCLUSIONS: Our study demonstrated that human resistin induces mitochondrial dysfunction by inducing abnormal mitochondrial fission. This result suggests that the resistin-CAP1 complex could be a potential therapeutic target for the treatment of obesity-related metabolic diseases such as diabetes and cardiometabolic diseases.