Acetyl-CoA Derived from Hepatic Peroxisomal ß-Oxidation Inhibits Autophagy and Promotes Steatosis via mTORC1 Activation.

Autophagy is activated by prolonged fasting but cannot overcome the ensuing hepatic lipid overload, resulting in fatty liver. Here, we describe a peroxisome-lysosome metabolic link that restricts autophagic degradation of lipids. Acyl-CoA oxidase 1 (Acox1), the enzyme that catalyzes the first step in peroxisomal ß-oxidation, is enriched in liver and further increases with fasting or high-fat diet (HFD). Liver-specific Acox1 knockout (Acox1-LKO) protected mice against hepatic steatosis caused by starvation or HFD due to induction of autophagic degradation of lipid droplets. Hepatic Acox1 deficiency markedly lowered total cytosolic acetyl-CoA levels, which led to decreased Raptor acetylation and reduced lysosomal localization of mTOR, resulting in impaired activation of mTORC1, a central regulator of autophagy. Dichloroacetic acid treatment elevated acetyl-CoA levels, restored mTORC1 activation, inhibited autophagy, and increased hepatic triglycerides in Acox1-LKO mice. These results identify peroxisome-derived acetyl-CoA as a key metabolic regulator of autophagy that controls hepatic lipid homeostasis.

Alterations of plasma exosomal proteins and motabolies are associated with the progression of castration-resistant prostate cancer.

BACKGROUND: Current diagnosis tools for prostate cancer (PCa) such as serum PSA detection and prostate biopsy cannot distinguish dormant tumors from invasive malignancies, either be used as prognosis marker for castration resistant prostate cancer (CRPC), the lethal stage of PCa patients. Exosomes have been widely investigated as promising biomarkers for various diseases. We aim to characterize the proteomic and metabolomic profile of exosomes and to evaluate their potential value for the diagnosis of PCa, especially CRPC. We also investigate the functions of some specific exosome biomarkers in the progression of CRPC. METHODS: Integrated proteomics and metabolomics analysis were performed for plasma-derived exosomes collected from tumor-free controls (TFC), PCa and CRPC patients. Expression of specific exosomal proteins were further validated by targeted 4D-parallel reaction monitoring (PRM) mass spectrometry among the three cohorts. Tissue distribution and functional role of exosomal protein LRG1 was studied in clinical PCa tissue samples and cell line models. RESULTS: Three potential exosomal protein markers were identified. The apolipoprotein E level in PCa samples was 1.7-fold higher than that in TFC (receiver operating characteristic value, 0.74). Similarly, the levels of exosome-derived leucine-rich alpha2-glycoprotein 1 (LRG1) and inter-alpha-trypsin inhibitor heavy chain H3 (ITIH3) in the CRPC group were 1.7 and 2.04 times, respectively, higher than those in the PCa group (ROC values, 0.84 and 0.85, respectively), indicating that LRG1 and ITIH3 could serve as predictive markers for CRPC. For metabolomic evaluation of exosomes, a series of differentially expressed metabolites were identified, and a combined metabolite panel showed ROC value of 0.94 for distinguishing PCa from TFC and 0.97 for distinguishing CRPC from PCa. Immunohistochemistry of tissue microarray showed that LRG1 protein was significantly upregulated in advanced prostate cancer and functional assay revealed that ectopic expression of LRG1 can significantly enhance the malignant phenotype of prostate cancer cells. More importantly, PCa cell derived LRG1-overexpressed exosomes remarkably promoted angiogenesis. CONCLUSION: Integration of proteomics and metabolomics data generated proteomic and metabolic signatures of plasma exosomes that may facilitate discrimination of CRPC from PCa and TFC patients, suggesting the potential of exosomal proteins and metabolites as CRPC markers. The study also confirmed the important role of exosomal protein LRG1 in PCa malignant progression.

The Chemical Compositions, and Antibacterial and Antioxidant Activities of Four Types of Citrus Essential Oils.

Nanfeng mandarins (Citrus reticulata Blanco cv. Kinokuni), Xunwu mandarins (Citrus reticulata Blanco), Yangshuo kumquats (Citrus japonica Thunb) and physiologically dropped navel oranges (Citrus sinensis Osbeck cv. Newhall) were used as materials to extract peel essential oils (EOs) via hydrodistillation. The chemical composition, and antibacterial and antioxidant activities of the EOs were investigated. GC-MS analysis showed that monoterpene hydrocarbons were the major components and limonene was the predominate compound for all citrus EOs. The antibacterial testing of EOs against five different bacteria (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium) was carried out using the filter paper method and the broth microdilution method. Kumquat EO had the best inhibitory effect on B. subtilis, E. coli and S. typhimurium with MIC (minimum inhibitory concentration) values of 1.56, 1.56 and 6.25 µL/mL, respectively. All citrus EOs showed the antioxidant activity of scavenging DPPH and ABTS free radicals in a dose-dependent manner. Nanfeng mandarin EO presented the best antioxidant activity, with IC50 values of 15.20 mg/mL for the DPPH assay and 0.80 mg/mL for the ABTS assay. The results also showed that the antibacterial activities of EOs might not be related to their antioxidant activities.

Mitochondrial Fatty Acid ß-Oxidation Inhibition Promotes Glucose Utilization and Protein Deposition through Energy Homeostasis Remodeling in Fish.

BACKGROUND: Fish cannot use carbohydrate efficiently and instead utilize protein for energy supply, thus limiting dietary protein storage. Protein deposition is dependent on protein turnover balance, which correlates tightly with cellular energy homeostasis. Mitochondrial fatty acid ß-oxidation (FAO) plays a crucial role in energy metabolism. However, the effect of remodeled energy homeostasis caused by inhibited mitochondrial FAO on protein deposition in fish has not been intensively studied. OBJECTIVES: This study aimed to identify the regulatory role of mitochondrial FAO in energy homeostasis maintenance and protein deposition by studying lipid, glucose, and protein metabolism in fish. METHODS: Carnitine-depleted male Nile tilapia (initial weight: 4.29 ± 0.12 g; 3 mo old) were established by feeding them with mildronate diets (1000 mg/kg/d) for 6 wk. Zebrafish deficient in the carnitine palmitoyltransferase 1b gene (cpt1b) were produced by using CRISPR/Cas9 gene-editing technology, and their males (154 ± 3.52 mg; 3 mo old) were used for experiments. Normal Nile tilapia and wildtype zebrafish were used as controls. We assessed nutrient metabolism and energy homeostasis-related biochemical and molecular parameters, and performed 14C-labeled nutrient tracking and transcriptomic analyses. RESULTS: The mitochondrial FAO decreased by 33.1-88.9% (liver) and 55.6-68.8% (muscle) in carnitine-depleted Nile tilapia and cpt1b-deficient zebrafish compared with their controls (P < 0.05). Notably, glucose oxidation and muscle protein deposition increased by 20.5-24.4% and 6.40-8.54%, respectively, in the 2 fish models compared with their corresponding controls (P < 0.05). Accordingly, the adenosine 5'-monophosphate-activated protein kinase/protein kinase B-mechanistic target of rapamycin (AMPK/AKT-mTOR) signaling was significantly activated in the 2 fish models with inhibited mitochondrial FAO (P < 0.05). CONCLUSIONS: These data show that inhibited mitochondrial FAO in fish induces energy homeostasis remodeling and enhances glucose utilization and protein deposition. Therefore, fish with inhibited mitochondrial FAO could have high potential to utilize carbohydrate. Our results demonstrate a potentially new approach for increasing protein deposition through energy homeostasis regulation in cultured animals.

Transurethral resection of ejaculatory duct combined with seminal vesiculoscopy for management of persistent or recurrent hemospermia in men with ejaculatory duct obstruction.

BACKGROUND: Persistent or recurrent haemospermia often occurs in individuals with ejaculatory duct obstruction (EDO). This study aimed to evaluate the efficacy and safety of transurethral resection of the ejaculatory duct (TURED) combined with seminal vesiculoscopy in treating persistent or recurrent haemospermia in men with EDO. METHODS: From June 2014 to March 2018, 103 consecutive patients with EDO who underwent TURED combined with seminal vesiculoscopy for persistent or recurrent haemospermia at the Department of Urology of West China Hospital were enrolled into this retrospective study. The patients were evaluated mainly by detailed history-taking and performing semen analysis, transrectal ultrasonography, and magnetic resonance imaging. RESULTS: Among the 103 patients, 79 (76.70%) had cysts of the lower male genitourinary tract; 63 (61.17%) had blood clots; and 32 (31.07%) had calculi in the seminal vesicle and/or prostatic utricle. The duration of postoperative follow-up was 12 months, and the symptoms of haemospermia disappeared in 96 (93.20%) patients. There was no significant difference in the semen PH and sperm count before and after surgery; however, the ejaculate volume and sperm motility significantly improved postoperatively. Except for two cases of acute urinary retention and one case of watery ejaculate after surgery, no severe postoperative complications, including epididymitis, urethral stricture, urinary incontinence, retrograde ejaculation, or rectal injury, were observed. CONCLUSION: TURED combined with seminal vesiculoscopy is a suitable method for the diagnosis and treatment of persistent or recurrent haemospermia in men with EDO.

The association between variants in the CFTR gene and nonobstructive male infertility: A meta-analysis.

The association of genetic variants and congenital bilateral absence of the vas deferens (CBAVD) has been well acknowledged. By contrast, the link between nonobstructive azoospermia (NOA) or oligospermia and alterations in the cystic fibrosis transmembrane conductive regulator (CFTR) remains inconclusive. To clarify the problem, a meta-analysis was performed out after systematically searching Pubmed, Web of Science, Embase and the Chinese national knowledge infrastructure (CNKI) database. As we know, the ∆F508 and IVS8-5T gene mutations are the most studied genetic variants in CFTR gene. We reviewed the data from male patients who underwent the aforementioned genetic test. Our study revealed that the IVS8-5T mutation may be positively associated with the risk of nonobstructive male infertility (odds ratio (OR) 1.69; 95% CI: 1.12-2.55). This association strengthened when concerning NOA (OR: 2.62; 95% CI: 1.49-4.61). However, the ∆F508 mutation seemed to be a smaller contributing factor to this risk (OR: 1.63; 95% CI: 0.86-3.08). Our study aims to clarify the association between the ∆F508 and IVS8-5T gene mutations and nonobstructive male infertility. Therefore, screening for the IVS8-5T mutation in the CFTR gene may be recommended for men with NOA or severe oligozoospermia seeking assisted reproductive technology (ART).

Fasting enhances cold resistance in fish through stimulating lipid catabolism and autophagy.

KEY POINTS: In a cold environment, mammals increase their food intake while fish decrease or stop feeding. However, the physiological value of fasting during cold resistance in fish is currently unknown. Fasting for more than 48 h enhanced acute cold resistance in zebrafish, which correlated with lipid catabolism and cell damage attenuation. Lipid catabolism and autophagy were necessary for cold resistance in fish and the inhibition of mitochondrial fatty acid ß-oxidation or autophagy weakened the fasting-induced cold resistance. Repression of mechanistic target of rapamycin (mTOR) signalling pathway by rapamycin largely mimicked the beneficial effects of fasting in promoting cold resistance, suggesting mTOR signalling may be involved in the fasting-induced cold resistance in fish. Our study demonstrates that fasting may be a protective strategy for fish to survive under cold stress. ABSTRACT: In cold environments, most homeothermic animals increase their food intake to supply more energy to maintain body temperature, whereas most poikilothermic animals such as fishes decrease or even stop feeding under cold stress. However, the physiological value of fasting during cold resistance in poikilotherms has not been explained. Here, we show that moderate fasting largely enhanced cold resistance in fish. By using pharmacological (fenofibrate, mildronate, chloroquine and rapamycin) and nutritional approaches (fatty acids diets and amino acids diets) in wild-type or specific gene knock-out zebrafish models (carnitine palmitoyltransferase-1b-deficient strain, CPT1b-/- , or autophagy-related protein 12-deficient strain, ATG12-/- ), we verified that fasting-stimulated lipid catabolism and autophagy played essential roles in the improved cold resistance. Moreover, suppression of the mechanistic target of rapamycin (mTOR) pathway by using rapamycin mostly mimicked the beneficial effects of fasting in promoting cold resistance as either the physiological phenotype or transcriptomic pattern. However, these beneficial effects were largely reduced when the mTOR pathway was activated through high dietary leucine supplementation. We conclude that fasting helps fish to resist cold stress by modulating lipid catabolism and autophagy, which correlates with the mTOR signalling pathway. Therefore, fasting can act as a protective strategy of fish in resisting coldness.

The comparisons in protective mechanisms and efficiencies among dietary α-lipoic acid, ß-glucan and l-carnitine on Nile tilapia infected by Aeromonas hydrophila.

Dietary α-lipoic acid (LA), ß-glucan (Gluc) and l-carnitine (L-Ca) are commonly used additives to promote fish growth and stress resistance in aquaculture production. However their mechanisms and efficiencies in helping fish to resist diseases have not been compared before. In this study, we fed Nile tilapia (Oreochromis niloticus) with diets containing appropriate doses of LA, Gluc and L-Ca for five weeks and further intraperitoneally injected the fish with Aeromonas hydrophila. After dietary treatment, none of the additives affected the fish growth, but dietary Gluc and L-Ca reduced protein and lipid body contents in fish, respectively. After A. hydrophila challenge, all fish treated with the three dietary additives showed higher survival rate, but those fed on dietary L-Ca had lower survival than those fed on LA and Gluc diets, indicating high protection efficiency of LA and Gluc. The protective mechanisms of the three feed additives were quite different under A. hydrophila infection. Dietary LA induced higher total antioxidant capacity and higher mRNA expression of anti-oxidative genes than other additives in liver and also activated partly the immune function in serum and spleen. Gluc largely increased the immune function by activating the immunity enzymes in serum, inducing inflammation in liver and increasing the expression of immune genes in spleen and head kidney. Gluc also increased partly the antioxidant capacity in serum and liver and lipid catabolism in liver. L-Ca largely increased lipid catabolism in liver while it increased partly the antioxidant capacities in serum and liver. Taken together, these results indicate that, dietary LA, Gluc and L-Ca have various protective mechanisms and differ in their efficiencies on resisting A. hydrophila infection in Nile tilapia.

Reduced oxidative stress increases acute cold stress tolerance in zebrafish.

Cold stress is a major threat to fish in both nature and aquaculture, and can induce oxidative stress in various fish. While the exact role of oxidative stress in cold-caused mortality is still unknown. The purpose of the present study was to evaluate the effects of oxidative stress on cold tolerance in fish and verify whether changing oxidative status could affect cold tolerance. We firstly demonstrated that acute cold exposure induced high oxidative stress in zebrafish liver, which may lead to mortality. Then we performed in vivo and in vitro experiments to determine the effects of the altered oxidative status on cold tolerance in zebrafish and zebrafish liver cell line (ZFL), respectively. In the in vivo study, the zebrafish which were fed with α-lipoic acid or reduced glutathione had lower cold-caused oxidative stress and tissues damage, and showed higher cold tolerance. In the experiment using zebrafish cells, increasing oxidative stress by H2O2 decreased the cellular cold tolerance, and the cold tolerance was partly recovered when oxidative stress was reduced by the addition of Vitamin C (VC). Taken together, we conclude that the reduction of oxidative stress increases cold tolerance in fish.

Aryl hydrocarbon receptor rs2066853 gene polymorphisms and male infertility risk: a meta-analysis.

To evaluate the relationship between the aryl hydrocarbon receptor (AHR) rs2066853 gene polymorphism and the risk of male infertility. PubMed, Embase, Web of Science, and Chinese National Knowledge Infrastructure (CNKI) were searched for relevant case-control studies up to 31 July 2019. Odds ratio (OR) and 95% confidence interval (95% CI) were used to assess the strength of associations. Finally, seven case-control studies involving 1247 cases and 1762 controls were included in this meta-analysis. The pooled results showed that there was no significant association between AHR rs2066853 gene polymorphism and male infertility risk (A vs. G: OR = 1.08, 95% CI = 0.83-1.39; AA vs. GG: OR = 1.16, 95% CI = 0.65-2.04; AA vs. GA + GG: OR = 1.17, 95% CI = 0.66-2.07; AA + GA vs. GG: OR = 0.99, 95% CI = 0.85-1.15). Subgroup analysis by ethnicity showed the same result. However, significant association was found between AHR rs2066853 gene polymorphism and male infertility risk in oligoasthenotspermia (A vs. G: OR = 2.52, 95% CI = 1.72-3.70). In conclusion, our meta-analysis indicated that AHR rs2066853 gene polymorphism might be associated with an increased susceptibility to oligoasthenotspermia.

TP53 gene Arg72Pro polymorphism and male infertility risk: A meta-analysis.

To evaluate the association between TP53 codon72 polymorphism and male infertility risk. We conducted a search on Medline, Embase, Web of Science and CNKI up to April 30, 2017. Odds ratio (OR) and 95% confidence interval (95% CI) were used to assess the strength of the association. Seven studies including 1,818 cases and 2,278 controls met the inclusion criteria. The pooled results indicated that no significant association was observed between TP53 codon72 polymorphism and male infertility risk (G versus C: OR = 1.11, 95%CI = 0.94-1.32; GG versus CC: OR = 1.26, 95%CI = 0.90-1.78; GG versus GC+CC: OR = 1.16, 95%CI = 0.90-1.49; GG+GC versus CC: OR = 1.15, 95%CI = 0.88-1.49). In the subgroup analysis by ethnicity, significant association was observed between TP53 codon72 polymorphism and male infertility risk in non-Chinese (G versus C: OR = 1.47, 95%CI = 1.14-1.89), but not in Chinese population (G versus C: OR = 1.03, 95%CI = 0.87-1.22). In conclusion, this study suggested that TP53 codon72 polymorphism might be associated with an increased susceptibility to male infertility in non-Chinese population, but not in Chinese population. Studies with larger sample sizes and representative population-based cases and well-matched controls are needed to validate our results.

Mechanisms and metabolic regulation of PPARα activation in Nile tilapia (Oreochromis niloticus).

Although the key metabolic regulatory functions of mammalian peroxisome proliferator-activated receptor α (PPARα) have been thoroughly studied, the molecular mechanisms and metabolic regulation of PPARα activation in fish are less known. In the first part of the present study, Nile tilapia (Nt)PPARα was cloned and identified, and high mRNA expression levels were detected in the brain, liver, and heart. NtPPARα was activated by an agonist (fenofibrate) and by fasting and was verified in primary hepatocytes and living fish by decreased phosphorylation of NtPPARα and/or increased NtPPARα mRNA and protein expression. In the second part of the present work, fenofibrate was fed to fish or fish were fasted for 4weeks to investigate the metabolic regulatory effects of NtPPARα. A transcriptomic study was also performed. The results indicated that fenofibrate decreased hepatic triglyceride and 18C-series fatty acid contents but increased the catabolic rate of intraperitoneally injected [1-(14)C] palmitate in vivo, hepatic mitochondrial ß-oxidation efficiency, the quantity of cytochrome b DNA, and carnitine palmitoyltransferase-1a mRNA expression. Fenofibrate also increased serum glucose, insulin, and lactate concentrations. Fasting had stronger hypolipidemic and gene regulatory effects than those of fenofibrate. Taken together, we conclude that: 1) liver is one of the main target tissues of the metabolic regulation of NtPPARα activation; 2) dephosphorylation is the basal NtPPARα activation mechanism rather than enhanced mRNA and protein expression; 3) activated NtPPARα has a hypolipidemic effect by increasing activity and the number of hepatic mitochondria; and 4) PPARα activation affects carbohydrate metabolism by altering energy homeostasis among nutrients.

Functional Variations in the NOS3 Gene Are Associated With Erectile Dysfunction Susceptibility, Age of Onset and Severity in a Han Chinese Population.

BACKGROUND: Impaired function of endothelial nitric oxide synthase (eNOS) is involved in the pathologic processes of erectile dysfunction (ED), and three functional polymorphisms (G894T, T-786C, and a tandem repeat of 27 bp in intron 4) in the NOS3 gene, which encodes eNOS, are associated with the clinical characteristics of ED in several populations. AIM: To investigate the effect of these variations of NOS3 on ED phenotypes and the response to sildenafil in a Han Chinese population. METHODS: This case-control study enrolled 112 patients with ED and 156 age-matched healthy men. Their medical history and laboratory data were collected. ED severity and response to sildenafil were assessed using the five-item International Index of Erectile Function (IIEF-5) score. Routine polymerase chain reaction and Sanger sequencing were used to genotype the three polymorphisms of NOS3. OUTCOMES: The frequencies of alleles, genotypes, and haplotypes of the loci in patients and controls; the IIEF-5 scores of patients carrying the risk and non-risk genotype; and the frequencies of risk and non-risk genotypes in patients with different ages at onset and responses to sildenafil were assessed. RESULTS: The frequencies of drinkers and diabetic and hyperlipidemic patients in the ED group were higher than those in the age-matched control group (P < .05). The distributions of alleles (G894T, P < .005; T-786C, P < .015), genotypes (G894T, P < 0.015; T-786C, P < .010), and haplotypes (G894T/T-786C, P < .015) of the NOS3 polymorphisms were significantly different between patients with ED and controls. An increased risk for earlier onset of ED was observed in the G894T risk genotype carriers (odds ratio = 3.572; P < .020). Patients with the risk genotype of T-786C exhibited lower IIEF-5 scores than patients with the non-risk genotype (8.2 ± 4.5 vs 12.2 ± 5.0; P < .015). The influence of the T-786C or G894T genotype on the response to sildenafil was not observed. CLINICAL TRANSLATION: The detectable effect of NOS3 functional polymorphisms on ED suggests their application potential as a molecular biomarker in predicting ED susceptibility and severity in the Han Chinese population. STRENGTHS & LIMITATIONS: This study provides strong evidence that NOS3 functional variation is an independent risk factor for ED in the Han Chinese population, which should be confirmed in larger cohorts considering the limited number of subjects in this study. CONCLUSION: These results are the first to identify a clear association between NOS3 functional variation and ED susceptibility, age at onset, and severity in the Han Chinese population. Yang B, Liu L, Peng Z, et al. Functional Variations in the NOS3 Gene Are Associated With Erectile Dysfunction Susceptibility, Age of Onset and Severity in a Han Chinese Population. J Sex Med 2017;14:551-557.

Effect of bioturbation of the mitten crab on distribution of tire wear particles and their combined effect on sediment ecosystem.

Tire wear particles (TWPs) are a major source of environmental microplastic pollution which gradually settle and accumulate in sediments after entering the aquatic environment, which can affect the behaviors of benthic organisms. Bioturbation of benthic species could affect the fate, impacts and potential risks of TWPs by altering the properties and structure of sediments. Therefore, in this study, the effect of TWPs on the burrowing activity of Chinese mitten crab (Eriocheir sinensis) was investigated. In addition, the effects of crab bioturbation on the distribution of TWPs and their additives were studied. The combined effects of TWPs and crab bioturbation on the microbial communities in the sediments were also explored. The results of this study showed that both TWPs and the leachate significantly inhibited the burrowing activity of crabs. TWPs in the surface layer of sediments were re-distributed by crab bioturbation and enriched mainly in the sediments near the burrow walls. Meanwhile, the heavy metals (i.e., Zn, Ca, Mg, Ba and Al) used as additives during the tire production in the burrow walls significantly increased as the accumulation of TWPs near burrow walls. In this study, TWP exposure decreased the bacterial diversity and abundance, as well as the functional genes related to carbon and nitrogen cycling process, but crab bioturbation increased them in the sediments of burrow walls by constructing a unique habitat. However, after TWPs entering into burrows, they were significantly decreased in the sediments near the burrow walls like the effects of TWPs, suggesting the negative effects of TWPs could play a dominant role in this combined system. Overall, this study is important for evaluating the distribution and effects of TWP pollution in the sediment ecosystem under biological factors such as bioturbation.

Effects of intensive oyster farming on nitrogen speciation in surface sediments from a typical subtropical mariculture bay.

The spatial-temporal distributions of various nitrogen (N) species in surface sediments were examined in a typical subtropical mariculture bay (Maowei Sea) in the northern Beibu Gulf to assess the impact of intensive oyster culture activities on sedimentary N speciation. The results indicated that the mean contents of total nitrogen (TN), extractable (labile) nitrogen (LN) and residual nitrogen (RN) in the surface sediments were 33.3 ± 15.5 µmol g-1, 13.8 ± 1.3 µmol g-1 and 19.5 ± 15.0 µmol g-1, respectively, which lacked significant seasonal variability (P > 0.05). Four forms of LN, namely ion extractable form (IEF-N), weak acid extractable form (WAEF-N), strong alkali extractable form (SAEF-N) and strong oxidant extractable form (SOEF-N) were identified based on sequential extraction. SOEF-N was the dominant form of LN, accounting for 67.8 ± 2.5 % and 63.7 ± 5.9 % in summer and winter, respectively. Spatially, the contents of sedimentary TN, LN, RN, WAEF-N and SOEF-N in intensive mariculture areas (IMA) were significantly higher than those in non-intensive mariculture areas (NIMA) during summer (P < 0.05). Stable nitrogen isotope (δ15N) mixing model revealed that shellfish biodeposition was the predominant source of sedimentary TN in IMA with a contribution of 67.8 ± 23.0 %, approximately 5.4 times that of NIMA (12.6 ± 3.3 %). Significant positive correlations (P < 0.05) were observed between most forms of N species (WAEF-N, SOEF-N, LN and RN) and shellfish-biodeposited N in the surface sediments during summer, indicating that intensive oyster farming greatly enhanced sedimentary TN accumulation.

Adipose tissue peroxisomal lipid synthesis orchestrates obesity and insulin resistance through LXR-dependent lipogenesis.

OBJECTIVE: Adipose tissue mass is maintained by a balance between lipolysis and lipid storage. The contribution of adipose tissue lipogenesis to fat mass, especially in the setting of high-fat feeding, is considered minor. Here we investigated the effect of adipose-specific inactivation of the peroxisomal lipid synthetic protein PexRAP on fatty acid synthase (FASN)-mediated lipogenesis and its impact on adiposity and metabolic homeostasis. METHODS: To explore the role of PexRAP in adipose tissue, we metabolically phenotyped mice with adipose-specific knockout of PexRAP. Bulk RNA sequencing was used to determine transcriptomic responses to PexRAP deletion and 14C-malonyl CoA allowed us to measure de novo lipogenic activity in adipose tissue of these mice. In vitro cell culture models were used to elucidate the mechanism of cellular responses to PexRAP deletion. RESULTS: Adipose-specific PexRAP deletion promoted diet-induced obesity and insulin resistance through activation of de novo lipogenesis. Mechanistically, PexRAP inactivation inhibited the flux of carbons to ethanolamine plasmalogens. This increased the nuclear PC/PE ratio and promoted cholesterol mislocalization, resulting in activation of liver X receptor (LXR), a nuclear receptor known to be activated by increased intracellular cholesterol. LXR activation led to increased expression of the phospholipid remodeling enzyme LPCAT3 and induced FASN-mediated lipogenesis, which promoted diet-induced obesity and insulin resistance. CONCLUSIONS: These studies reveal an unexpected role for peroxisome-derived lipids in regulating LXR-dependent lipogenesis and suggest that activation of lipogenesis, combined with dietary lipid overload, exacerbates obesity and metabolic dysregulation.

Mechanisms of imbalanced testicular homeostasis in infancy due to aberrant histone acetylation in undifferentiated spermatogonia under different concentrations of Di(2-ethylhexyl) phthalate (DEHP) exposure.

Di (2-ethylhexyl) phthalate (DEHP), identified as an endocrine-disrupting chemical, is associated with reproductive toxicity. This association is particularly noteworthy in newborns with incompletely developed metabolic functions, as exposure to DEHP can induce enduring damage to the reproductive system, potentially influencing adult reproductive health. In this study, we continuously administered 40 µg/kg and 80 µg/kg DEHP to postnatal day 5 (PD5) mice for ten days to simulate low and high doses of DEHP exposure during infancy. Utilizing single-cell RNA sequencing (scRNA-seq), our analysis revealed that varying concentrations of DEHP exposure during infancy induced distinct DNA damage response characteristics in testicular Undifferentiated spermatogonia (Undiff SPG). Specifically, DNA damage triggered mitochondrial dysfunction, leading to acetyl-CoA content alterations. Subsequently, this disruption caused aberrations in histone acetylation patterns, ultimately resulting in apoptosis of Undiff SPG in the 40 µg/kg DEHP group and autophagy in the 80 µg/kg DEHP group. Furthermore, we found that DEHP exposure impacts the development and functionality of Sertoli and Leydig cells through the focal adhesion and PPAR signaling pathways, respectively. We also revealed that Leydig cells regulate the metabolic environment of Undiff SPG via Ptn-Sdc4 and Mdk-Sdc4 after DEHP exposure. Finally, our study provided pioneering evidence that disruptions in testicular homeostasis induced by DEHP exposure during infancy endure into adulthood. In summary, this study elucidates the molecular mechanisms through which DEHP exposure during infancy influences the development of testicular cell populations.

Liver ACOX1 regulates levels of circulating lipids that promote metabolic health through adipose remodeling.

The liver gene expression of the peroxisomal ß-oxidation enzyme acyl-coenzyme A oxidase 1 (ACOX1), which catabolizes very long chain fatty acids (VLCFA), increases in the context of obesity, but how this pathway impacts systemic energy metabolism remains unknown. Here, we show that hepatic ACOX1-mediated ß-oxidation regulates inter-organ communication involved in metabolic homeostasis. Liver-specific knockout of Acox1 (Acox1-LKO) protects mice from diet-induced obesity, adipose tissue inflammation, and systemic insulin resistance. Serum from Acox1-LKO mice promotes browning in cultured white adipocytes. Global serum lipidomics show increased circulating levels of several species of ω-3 VLCFAs (C24-C28) with previously uncharacterized physiological role that promote browning, mitochondrial biogenesis and Glut4 translocation through activation of the lipid sensor GPR120 in adipocytes. This work identifies hepatic peroxisomal ß-oxidation as an important regulator of metabolic homeostasis and suggests that manipulation of ACOX1 or its substrates may treat obesity-associated metabolic disorders.

Tubular CPT1A deletion minimally affects aging and chronic kidney injury.

Kidney tubules use fatty acid oxidation (FAO) to support their high energetic requirements. Carnitine palmitoyltransferase 1A (CPT1A) is the rate-limiting enzyme for FAO, and it is necessary to transport long-chain fatty acids into mitochondria. To define the role of tubular CPT1A in aging and injury, we generated mice with tubule-specific deletion of Cpt1a (Cpt1aCKO mice), and the mice were either aged for 2 years or injured by aristolochic acid or unilateral ureteral obstruction. Surprisingly, Cpt1aCKO mice had no significant differences in kidney function or fibrosis compared with wild-type mice after aging or chronic injury. Primary tubule cells from aged Cpt1aCKO mice had a modest decrease in palmitate oxidation but retained the ability to metabolize long-chain fatty acids. Very-long-chain fatty acids, exclusively oxidized by peroxisomes, were reduced in kidneys lacking tubular CPT1A, consistent with increased peroxisomal activity. Single-nuclear RNA-Seq showed significantly increased expression of peroxisomal FAO enzymes in proximal tubules of mice lacking tubular CPT1A. These data suggest that peroxisomal FAO may compensate in the absence of CPT1A, and future genetic studies are needed to confirm the role of peroxisomal ß-oxidation when mitochondrial FAO is impaired.

Influence of glucuronidation and reduction modifications of resveratrol on its biological activities.

Resveratrol (3,5,4'-trihydroxystilbene, RES), a star among dietary polyphenols, shows a wide range of biological activities, but it is rapidly and extensively metabolized into its glucuronide and sulfate conjugates as well as to the corresponding reduced products. This begs the question of whether the metabolites of RES contribute to its in vivo biological activity. To explore this possibility, we synthesized its glucuronidation (3-GR and 4'-GR) and reduction (DHR) metabolites, and evaluated the effect of these structure modifications on biological activities, including binding ability with human serum albumin (HSA), antioxidant activity in homogeneous solutions and heterogeneous media, anti-inflammatory activity, and cytotoxicity against various cancer cell lines. We found that 1) 4'-GR, DHR and RES show nearly equal binding to HSA, mainly through hydrogen bonding, whereas 3-GR adopts a quite different orientation mode upon binding, thereby resulting in reduced ability; 2) 3-GR shows comparable (even equal) ability to RES in FRAP- and AAPH-induced DNA strand breakage assays; DHR, 3-GR, and 4'-GR exhibit anti-hemolysis activity comparable to that of RES; additionally, 3-GR and DHR retain some degree activity of the parent molecule in DPPH.-scavenging and cupric ion-initiated oxidation of LDL assays, respectively; 3) compared to RES, 4'-GR displays equipotent ability in the inhibition of COX-2, and DHR presents comparable activity in inhibiting NO production and growth of SMMC-7721 cells. Relative to RES, its glucuronidation and reduction metabolites showed equal, comparable, or some degree of activity in the above assays, depending on the specific compound and test model, which probably supports their roles in contributing to the in vivo biological activities of the parent molecule.