Autotaxin signaling facilitates ß cell dedifferentiation and dysfunction induced by Sirtuin 3 deficiency.

OBJECTIVE: ß cell dedifferentiation may underlie the reversible reduction in pancreatic ß cell mass and function in type 2 diabetes (T2D). We previously reported that ß cell-specific Sirt3 knockout (Sirt3f/f;Cre/+) mice developed impaired glucose tolerance and glucose-stimulated insulin secretion after feeding with high fat diet (HFD). RNA sequencing showed that Sirt3-deficient islets had enhanced expression of Enpp2 (Autotaxin, or ATX), a secreted lysophospholipase which produces lysophosphatidic acid (LPA). Here, we hypothesized that activation of the ATX/LPA pathway contributed to pancreatic ß cell dedifferentiation in Sirt3-deficient ß cells. METHODS: We applied LPA, or lysophosphatidylcoline (LPC), the substrate of ATX for producing LPA, to MIN6 cell line and mouse islets with altered Sirt3 expression to investigate the effect of LPA on ß cell dedifferentiation and its underlying mechanisms. To examine the pathological effects of ATX/LPA pathway, we injected the ß cell selective adeno-associated virus (AAV-Atx-shRNA) or negative control AAV-scramble in Sirt3f/f and Sirt3f/f;Cre/+ mice followed by 6-week of HFD feeding. RESULTS: In Sirt3f/f;Cre/+ mouse islets and Sirt3 knockdown MIN6 cells, ATX upregulation led to increased LPC with increased production of LPA. The latter not only induced reversible dedifferentiation in MIN6 cells and mouse islets, but also reduced glucose-stimulated insulin secretion from islets. In MIN6 cells, LPA induced phosphorylation of JNK/p38 MAPK which was accompanied by ß cell dedifferentiation. The latter was suppressed by inhibitors of LPA receptor, JNK, and p38 MAPK. Importantly, inhibiting ATX in vivo improved insulin secretion and reduced ß cell dedifferentiation in HFD-fed Sirt3f/f;Cre/+ mice. CONCLUSIONS: Sirt3 prevents ß cell dedifferentiation by inhibiting ATX expression and upregulation of LPA. These findings support a long-range signaling effect of Sirt3 which modulates the ATX-LPA pathway to reverse ß cell dysfunction associated with glucolipotoxicity.

Pancreatic Sirtuin 3 Deficiency Promotes Hepatic Steatosis by Enhancing 5-Hydroxytryptamine Synthesis in Mice With Diet-Induced Obesity.

Sirtuin 3 (SIRT3) is a protein deacetylase regulating ß-cell function through inhibiting oxidative stress in obese and diabetic mice, but the detailed mechanism and potential effect of ß-cell-specific SIRT3 on metabolic homeostasis, and its potential effect on other metabolic organs, are unknown. We found that glucose tolerance and glucose-stimulated insulin secretion were impaired in high-fat diet (HFD)-fed ß-cell-selective Sirt3 knockout (Sirt3 f/f;Cre/+) mice. In addition, Sirt3 f/f;Cre/+ mice had more severe hepatic steatosis than Sirt3 f/f mice upon HFD feeding. RNA sequencing of islets suggested that Sirt3 deficiency overactivated 5-hydroxytryptamine (5-HT) synthesis as evidenced by upregulation of tryptophan hydroxylase 1 (TPH1). 5-HT concentration was increased in both islets and serum of Sirt3 f/f;Cre/+ mice. 5-HT also facilitated the effect of palmitate to increase lipid deposition. Treatment with TPH1 inhibitor ameliorated hepatic steatosis and reduced weight gain in HFD-fed Sirt3 f/f;Cre/+ mice. These data suggested that under HFD feeding, SIRT3 deficiency in ß-cells not only regulates insulin secretion but also modulates hepatic lipid metabolism via the release of 5-HT.

Alterations in Gut Microbiota of Patients With COVID-19 During Time of Hospitalization.

BACKGROUND & AIMS: Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects gastrointestinal tissues, little is known about the roles of gut commensal microbes in susceptibility to and severity of infection. We investigated changes in fecal microbiomes of patients with SARS-CoV-2 infection during hospitalization and associations with severity and fecal shedding of virus. METHODS: We performed shotgun metagenomic sequencing analyses of fecal samples from 15 patients with Coronavirus Disease 2019 (COVID-19) in Hong Kong, from February 5 through March 17, 2020. Fecal samples were collected 2 or 3 times per week from time of hospitalization until discharge; disease was categorized as mild (no radiographic evidence of pneumonia), moderate (pneumonia was present), severe (respiratory rate ≥30/min, or oxygen saturation ≤93% when breathing ambient air), or critical (respiratory failure requiring mechanical ventilation, shock, or organ failure requiring intensive care). We compared microbiome data with those from 6 subjects with community-acquired pneumonia and 15 healthy individuals (controls). We assessed gut microbiome profiles in association with disease severity and changes in fecal shedding of SARS-CoV-2. RESULTS: Patients with COVID-19 had significant alterations in fecal microbiomes compared with controls, characterized by enrichment of opportunistic pathogens and depletion of beneficial commensals, at time of hospitalization and at all timepoints during hospitalization. Depleted symbionts and gut dysbiosis persisted even after clearance of SARS-CoV-2 (determined from throat swabs) and resolution of respiratory symptoms. The baseline abundance of Coprobacillus, Clostridium ramosum, and Clostridium hathewayi correlated with COVID-19 severity; there was an inverse correlation between abundance of Faecalibacterium prausnitzii (an anti-inflammatory bacterium) and disease severity. Over the course of hospitalization, Bacteroides dorei, Bacteroides thetaiotaomicron, Bacteroides massiliensis, and Bacteroides ovatus, which downregulate expression of angiotensin-converting enzyme 2 (ACE2) in murine gut, correlated inversely with SARS-CoV-2 load in fecal samples from patients. CONCLUSIONS: In a pilot study of 15 patients with COVID-19, we found persistent alterations in the fecal microbiome during the time of hospitalization, compared with controls. Fecal microbiota alterations were associated with fecal levels of SARS-CoV-2 and COVID-19 severity. Strategies to alter the intestinal microbiota might reduce disease severity.

Mass spectrometry imaging and monitoring of in vivo glutathione-triggered cisplatin release from nanoparticles in the kidneys.

An increasing number of studies have reported the use of various nanoparticles to encapsulate cisplatin, a frontline chemotherapeutic drug against a broad-spectrum of cancers, for overcoming its inherent drawbacks in clinical applications. Nevertheless, few analytical methods or instruments could provide the precise distribution information on this platinum drug in biological tissues. Herein, we provide the first evidence of applying matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to assess the spatial distribution of cisplatin released from the cell-penetrating poly(disulfide) (CPD)-modified hollow iron oxide nanoparticles (hFe3O4-MPS-CPD) at the kidneys via an in situ glutathione (GSH) responsive mode. The cisplatin released from the nanoparticles triggered by GSH was successfully examined as [Pt(DDTC)2]+ (m/z 491.01) and [Pt(DDTC)3]+ (m/z 639.04) by MALDI-MS after derivatization using diethyldithiocarbamate. The in situ spatial distribution of [Pt(DDTC)2]+ and [Pt(DDTC)3]+ in the kidneys was then mapped using MALDI-MSI. This study presents an optimized analytical approach to evaluate and map the metallodrug in biological tissue samples in an efficient and convenient manner, offering great assistance in investigating the biodistribution of cisplatin delivered by nanoparticles, and sheds light on facilitating the studies of the pharmacokinetics of cisplatin in biomedical research.

Chronic exposure to tetrabromodiphenyl ether (BDE-47) aggravates hepatic steatosis and liver fibrosis in diet-induced obese mice.

Exposure to polybrominated diphenyl ethers (PBDEs), is closely associated with the occurrence of obesity and non-alcoholic fatty liver disease (NAFLD), yet their pathological effects and underlying mechanisms remain unclear. To examine the role of 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47) in the progression of NAFLD under obese condition, male C57BL/6 J mice were fed with diet interaction for 15 weeks and subcutaneously injected with BDE-47 (7 mg/kg or 70 mg/kg) or the vehicle weekly. BDE-47 exposure (70 mg/kg) significantly elevated the body weight and worsened hepatic steatosis along with increased inflammation in high fat diet (HFD) fed mice. Furthermore, integration analysis of lipidomics and gene expression revealed that BDE-47 up-regulated triglyceride synthesis but suppressed lipid exportation and ß oxidation, aggravating the accumulation of hepatic lipid in HFD fed mice. In addition, the increase of liver fibrosis, serum transaminase levels, as well as lipid peroxidation have been observed in mice co-treated with BDE-47 and HFD. Moreover, BDE-47-induced fibrogenic responses in hepatocytes were suppressed by antioxidants, which confirmed that BDE-47-induced liver fibrosis was tightly associated with oxidative stress. In conclusion, these results provided new and robust evidence for revealing the hepatoxicity of BDE-47 under obese condition and illustrated the underlying mechanism of BDE-47 induced liver fibrosis.

PFOA and PFOS promote diabetic renal injury in vitro by impairing the metabolisms of amino acids and purines.

BACKGROUND: Environmental pollutants, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), are common surfactants in various consumer products. Epidemiological studies have demonstrated the association of diabetic kidney diseases with PFOA and PFOS. However, mechanisms of metabolic alterations involved are still unclear. METHODS: Considering their involvement of glomerular hemodynamics, rat mesangial cells (MCs) are used as an in vitro model of diabetic kidney diseases for exposure to PFOS/PFOA under diabetic condition. Non-targeted metabolomics studies based on liquid chromatography-high resolution mass spectrometry were conducted to determine how PFOA/PFOS promoted fibrotic and proinflammatory responses in the MCs under diabetic condition. RESULTS: Exposure of PFOA/PFOS (10 µM) increased oxidative stress and the levels of fibrotic and proinflammatory markers in MCs under diabetic condition. We demonstrated for the first time that PFOA and PFOS altered amino acid biosynthesis, citrate cycle, and purine metabolism in MCs under diabetic condition. Compared with diabetic condition, the exposure of PFOA and PFOS under diabetic condition more significantly altered the levels of 13 intracellular metabolites, including L-tyrosine, L-phenylalanine, L-arginine, L-tryptophan, AMP, ADP, UMP, inosine, and hypoxanthine, which have been reported to be related to kidney injury. In addition, PFOA/PFOS treatment significantly altered the expression levels of key enzymes involved in these metabolisms. Treatment with L-tyrosine, L-phenylalanine, L-arginine, and L-tryptophan reduced the levels of fibrotic and inflammatory markers induced by PFOA/PFOS. CONCLUSION: Our results suggest that under diabetic condition, exposure of PFOA or PFOS aggravated diabetic kidney injury in vitro by impairing metabolisms of amino acids and purines to induce more fibrosis and inflammation in MCs.

Prenatal exposure to ambient fine particulate matter induces dysregulations of lipid metabolism in adipose tissue in male offspring.

Prenatal exposure to ambient fine particles (diameter < 0.25 µm, PM2.5) has been found to be associated with abnormal growth and development in offspring. However, the effects of PM2.5 on the lipid metabolism of adipose tissue in offspring are unclear. In the present study, we established a mouse model of prenatal exposure to PM2.5 by intratracheal instillation to pregnant C57BL/6 female mice with PM2.5 suspension or normal saline. We found that prenatal exposure to PM2.5 of a mouse model reduced body weight in adult male offspring after 6 weeks old. Histological analysis showed that the adipocyte size was significantly reduced in epididymal adipose tissue (eWAT) in male offspring, but not in brown adipose tissue. The expression levels of genes related to fatty acid synthesis (ACC1, ACSL1) and oxidation (PPARα) in eWAT were also significantly decreased. In addition, downregulation of pro-inflammatory cytokines (TNFα, IL-1ß, IL-6) was also observed. Lipidomics analysis of eWAT demonstrated that prenatal exposure of PM2.5 reduced lysophosphatidylcholines (LPC), phosphatidylcholines (PC), phosphatidylethanolamines (PE), sphingomyelins (SM), and ceramides (Cer), indicating that metabolic pathways, including SM-Cer signaling and glycerophospholipids remodeling, were disrupted. In summary, prenatal exposure to PM2.5 was associated with the dysregulations in lipid metabolism of eWAT and pro-inflammatory response in male offspring.

Profiles, variability, and predictors of urinary benzotriazoles and benzothiazoles in pregnant women from Wuhan, China.

BACKGROUND: Benzotriazoles (BTRs) and benzothiazoles (BTHs) are emerging contaminants with high production volume worldwide, which exhibit potential health risk to human. To date, little is known about the exposure of BTRs and BTHs (BTs) on human, especially in the context of pregnancy. OBJECTIVES: We aimed to characterize the exposure profiles, temporal variability, and potential predictors of urinary BTs during pregnancy. METHODS: Between 2014 and 2015, we recruited 856 pregnant women in Wuhan who provided urine samples at three trimesters (13.1 ±â€¯1.1, 23.7 ±â€¯3.2, and 35.7 ±â€¯3.4 gestational weeks). We measured the urinary concentrations of five BTRs (1­H­benzotriazole, 1­hydroxy­benzotriazole, xylyltriazole, tolyltriazole, 5­chloro­1­H­benzotriazole) and five BTHs (benzothiazole, 2­hydroxy­benzothiazole, 2­methylthio­benzothiazole, 2­amino­benzothiazole, 2­thiocyanomethylthio­benzothiazole) to characterize the exposure profiles of BTs. We calculated the intra-class correlation coefficients (ICCs) to assess the temporal variability and investigated potential predictors of urinary BTs by using the mixed models. RESULTS: Most of the targeted BTs were detected in over 50% of urine samples, except for 5­chloro­1­H­benzotriazole (9.3%) and 2­thiocyanomethylthio-benzothiazole (1.4%). The predominant BTRs in urine was 1­hydroxy­benzotriazole [Geometric Mean (GM): 0.77 ng/mL]. Benzothiazole was the major derivative in urine samples with a GM concentration of 1.6 ng/mL. Correlations among BTHs (r = 0.04-0.39) were higher than that among BTRs (r = 0.02-0.14). The exposure pattern was constant at low level and co-exposure to all the targeted compounds was infrequent during pregnancy. Urinary concentrations of BTRs exhibited considerable within-subject variation (ICCs: 0.12-0.56) during pregnancy. Relatively high temporal reliability was observed for urinary concentrations of BTHs with ICCs ranging from 0.42 to 0.85. It was found that parity, household income, pregnancy occupational status, sampling season and menstrual cycle were associated with urinary concentrations of BTs in pregnant women (P < 0.05). CONCLUSIONS: To the best of our knowledge, this is the first study to report the exposure profiles, variability and predictors of urinary BTs among pregnant women. Exposure assessment using multiple samples is essential in reducing measurement errors and identifying susceptible window of exposure in etiological studies. The potential predictors of urinary BTs raised concerns on tracing exposure routes and eliminating confounding variables in future studies.

Metabolomics studies on db/db diabetic mice in skeletal muscle reveal effective clearance of overloaded intermediates by exercise.

Type 2 diabetes mellitus (T2DM) is characterized by hyperinsulinemia, hyperglycemia and insulin resistance, which correlated with high mortality worldwide. Exercise is one of the effective lifestyle interventions in maintaining blood glucose level in the normal range and lowering risk factors. Metabolomics approaches are powerful tools in systematic study of overall metabolic changes in response to disease or interventions. In this study, mass spectrometry-based metabolomics studies were performed to investigate the regulatory effect of moderate intensity of exercise on db/db diabetic mice in skeletal muscle. Both liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) have been carried out to monitor a wide range of regulated metabolites. Ninety-five metabolites were identified which contributing to the discrimination of db/m  + control and db/db diabetic mice. The regulatory effects of exercise on these metabolites were mainly focusing on attenuating the levels of long-chain fatty acids (C14 to C18) and medium-to long-chain acylcarnitines (C12 to C18), indicated that exercise might play a positive role in inhibiting the accumulation of excessive lipids, which is positively related to insulin resistance. In addition, uric acid, which is a risk factor for inflammation, cardiovascular complications, and fatty liver in diabetic patients, together with its intermediates (such as inosinic acid, hypoxanthine, etc.) in purine metabolism pathway, were also substantially down regulated after exercise, indicating exercise might also be protective against hyperuricemia related risks in T2DM. These findings reveal that moderate intensity of exercise might play a positive role in improving the efficiency of lipid metabolism in skeletal muscle and meanwhile enhancing uric acid clearance to prevent lipid accumulation, which might contribute to improved body fitness and body muscle composition.

Early-life exposure to endocrine disrupting chemicals associates with childhood obesity.

Increasing prevalence of childhood obesity poses threats to the global health burden. Because this rising prevalence cannot be fully explained by traditional risk factors such as unhealthy diet and physical inactivity, early-life exposure to endocrine disrupting chemicals (EDCs) is recognized as emerging novel risk factors for childhood obesity. EDCs can disrupt the hormone-mediated metabolic pathways, affect children's growth and mediate the development of childhood obesity. Many organic pollutants are recently classified to be EDCs. In this review, we summarized the epidemiological and laboratory evidence related to EDCs and childhood obesity, and discussed the possible mechanisms underpinning childhood obesity and early-life exposure to non-persistent organic pollutants (phthalates, bisphenol A, triclosan) and persistent organic pollutants (dichlorodiphenyltrichloroethane, polychlorinated biphenyls, polybrominated diphenyl ethers, per- and polyfluoroalkyl substances). Understanding the relationship between EDCs and childhood obesity helps to raise public awareness and formulate public health policy to protect the youth from exposure to the harmful effects of EDCs.

The brominated flame retardant BDE 47 upregulates purine metabolism and mitochondrial respiration to promote adipocyte differentiation.

Adipocyte differentiation is closely associated with obesity and obesity-induced metabolic disorders. Epidemiological studies have demonstrated the association of obesity with environmental pollutants, such as polybrominated diphenyl ethers (PBDEs), common flame retardants in various consumer products. However, their obesogenic effects and mechanism are underexplored. We employed non-targeted metabolomics studies based on liquid chromatography-high resolution mass spectrometry to determine how 2,2',4,4'-tetra-brominated biphenyl ether (BDE 47), one of the main congeners of PBDEs detected in human tissue, promotes adipocyte differentiation of mouse preadipocyte 3 T3-L1 cells. The promoting effects of BDE 47 exposure (5 or 10 µM) on adipocyte differentiation were confirmed by enhancing lipid accumulation and expression levels of biomarkers of adipogenesis. For the first time, we demonstrated that BDE 47 upregulated purine metabolism and altered glutathione metabolism to promote oxidative stress and uric acid production in adipocytes. BDE 47 also elevated mitochondrial respiration and glycolysis in adipocytes to induce more ATP to combat oxidative stress. Antioxidant treatments, including the suppression of xanthine oxidase, inhibited the effects of BDE 47 on inducing oxidative stress and lipid accumulation. BDE 47 may be a potential environmental obesogen by providing a permissive oxidative environment to induce adipocyte differentiation.

LC-MS-based metabolomics revealed SLC25A22 as an essential regulator of aspartate-derived amino acids and polyamines in KRAS-mutant colorectal cancer.

SLC25A22, which encodes the mitochondrial glutamate transporter, is overexpressed in colorectal cancer (CRC) and is essential for the proliferation of CRC cells harboring KRAS mutations. However, the role of SLC25A22 on metabolic regulation in KRAS-mutant CRC cells has not been comprehensively characterized. We performed non-targeted metabolomics, targeted metabolomics and isotope kinetic analysis of KRAS-mutant DLD1 cells with or without SLC25A22 knockdown using ultra-high-performance liquid chromatography (UHPLC) coupled to Orbitrap mass spectrometry (MS) or tandem MS (MS/MS). Global metabolomics analysis identified 35 altered metabolites, which were attributed to alanine, aspartate and glutamate metabolism, urea cycle and polyamine metabolism. Targeted metabolomics including 24 metabolites revealed that most tricarboxylic acid (TCA) cycle intermediates, aspartate-derived asparagine, alanine and ornithine-derived polyamines were strongly down-regulated in SLC25A22 knockdown cells. Moreover, targeted kinetic isotope analysis showed that most of the 13C-labeled ornithine-derived polyamines were significantly decreased in SLC25A22 knockdown cells and culture medium. Exogenous addition of polyamines could significantly promote cell proliferation in DLD1 cells, highlighting their potential role as oncogenic metabolites that function downstream of SLC25A22-mediated glutamine metabolism. Collectively, SLC25A22 acts as an essential metabolic regulator during CRC progression as it promotes the synthesis of aspartate-derived amino acids and polyamines in KRAS mutant CRC cells.

Persistent Organic Pollutants as Risk Factors for Obesity and Diabetes.

PURPOSE OF REVIEW: The rising prevalence of obesity and diabetes cannot be fully explained by known risk factors, such as unhealthy diet, a sedentary lifestyle, and family history. This review summarizes the available studies linking persistent organic pollutants (POPs) to obesity and diabetes and discusses plausible underlying mechanisms. RECENT FINDINGS: Increasing evidence suggest that POPs may act as obesogens and diabetogens to promote the development of obesity and diabetes and induce metabolic dysfunction. POPs are synthesized chemicals and are used widely in our daily life. These chemicals are resistant to degradation in chemical or biological processes, which enable them to exist in the environment persistently and to be bio-accumulated in animal and human tissue through the food chain. Increasingly, epidemiologic studies suggest a positive association between POPs and risk of developing diabetes. Understanding the relationship of POPs with obesity and diabetes may shed light on preventive strategies for obesity and diabetes.

Sirt3 Deficiency Increased the Vulnerability of Pancreatic Beta Cells to Oxidative Stress-Induced Dysfunction.

AIMS: Hyperlipidemia-induced oxidative stress is considered to be one of the main pathogenic factors that contribute to pancreatic beta cell dysfunction in the development of type 2 diabetes (T2D). Sirtuin 3 (Sirt3) is abundantly expressed in the mitochondria as an NAD+-dependent deacetylase and regulates mitochondrial adaptive responses to oxidative stress. We examined the antioxidant defense mechanism of Sirt3 in pancreatic beta cells in the context of hyperlipidemia. RESULTS: Chronic high-fat diet (HFD) feeding caused elevated oxidative stress accompanied by reduced Sirt3 expression in the pancreatic beta cells of wild-type mice. Primary pancreatic islets of Sirt3 knockout (KO) mice and murine pancreatic MIN6 cells with downregulated Sirt3 expression showed increased superoxide dismutase 2 (SOD2) acetylation and reduced glucose-stimulated insulin secretion and glucose-stimulated adenosine triphosphate (ATP) generation. Moreover, Sirt3 deficiency sensitized the pancreatic islets and MIN6 cells to palmitate- and H2O2-induced beta cell dysfunction linked with aggravated c-Jun N-terminal kinase phosphorylation and cleaved caspase-3 expression. These negative effects were reversed by antioxidant chemical treatment or restoration of Sirt3 in KO islets. Finally, overexpression of Sirt3 in MIN6 cells partially rescued palmitate-induced reactive oxygen species generation, pancreatic and duodenal homeobox-1 (Pdx-1) nucleo-cytoplasmic translocation, and beta cell dysfunction. INNOVATION: We present that Sirt3 expression protected pancreatic beta cells from lipotoxicity by antagonizing oxidative stress-induced cell damage. CONCLUSION: These results suggest that Sirt3 may be a target for amelioration of beta cell dysfunction due to obesity and T2D. Antioxid. Redox Signal. 27, 962-976.

TGF-ß/Smad3 signalling regulates the transition of bone marrow-derived macrophages into myofibroblasts during tissue fibrosis.

Myofibroblasts are a main cell-type of collagen-producing cells during tissue fibrosis, but their origins remains controversial. While bone marrow-derived myofibroblasts in renal fibrosis has been reported, the cell origin and mechanisms regulating their transition into myofibroblasts remain undefined. In the present study, cell lineage tracing studies by adoptive transfer of GFP+ or dye-labelled macrophages identified that monocyte/macrophages from bone marrow can give rise to myofibroblasts via the process of macrophage-myofibroblast transition (MMT) in a mouse model of unilateral ureteric obstruction. The MMT cells were a major source of collagen-producing fibroblasts in the fibrosing kidney, accounting for more than 60% of α-SMA+ myofibroblasts. The MMT process occurred predominantly within M2-type macrophages and was regulated by TGF-ß/Smad3 signalling as deletion of Smad3 in the bone marrow compartment of GFP+ chimeric mice prevented the M2 macrophage transition into the MMT cells and progressive renal fibrosis. In vitro studies in Smad3 null bone marrow macrophages also showed that Smad3 was required for TGF-ß1-induced MMT and collagen production. In conclusion, we have demonstrated that bone marrow-derived fibroblasts originate from the monocyte/macrophage population via a process of MMT. This process contributes to progressive renal tissue fibrosis and is regulated by TGF-ß/Smad3 signalling.

microRNAs in Diabetic Kidney Disease.

Diabetes and diabetic kidney diseases have continually exerted a great burden on our society. Although the recent advances in medical research have led to a much better understanding of diabetic kidney diseases, there is still no successful strategy for effective treatments for diabetic kidney diseases. Recently, treatment of diabetic kidney diseases relies either on drugs that reduce the progression of renal injury or on renal replacement therapies, such as dialysis and kidney transplantation. On the other hand, searching for biomarkers for early diagnosis and effective therapy is also urgent. Discovery of microRNAs has opened to a novel field for posttranscriptional regulation of gene expression. Results from cell culture experiments, experimental animal models, and patients under diabetic conditions reveal the critical role of microRNAs during the progression of diabetic kidney diseases. Functional studies demonstrate not only the capability of microRNAs to regulate expression of target genes, but also their therapeutic potential to diabetic kidney diseases. The existence of microRNAs in plasma, serum, and urine suggests their possibility to be biomarkers in diabetic kidney diseases. Thus, identification of the functional role of microRNAs provides an essentially clinical impact in terms of prevention and treatment of progression in diabetic kidney diseases as it enables us to develop novel, specific therapies and diagnostic tools for diabetic kidney diseases.

Lingzhilactones from Ganoderma lingzhi ameliorate adriamycin-induced nephropathy in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Several Ganoderma fungi are well-known for their medical uses to treat cancer, insomnia and kidney disease in East Asia. Triperpenoids and polysaccharides have been considered for a long time to be the major active components of the genus Ganoderma. The present study is to examine the effects of lingzhilactones from G. lingzhi on adriamycin-induced nephropathy in mice. MATERIALS AND METHODS: A combination of various chromatography led to the isolation of lingzhilactones A-C, their structures were identified by spectroscopic and computational methods. The intracellular reactive oxygen species (ROS) was detected with the carboxymethyl-H2-dichlorofluorescein diacetate fluoroprobe. The fibrotic markers were analyzed by real-time RT-PCR and Western blot analyses. Detection of SEAP was conducted with the chemiluminescent. Urine albumin was measured using an ELISA assay. Histology and immunohistochemical staining was used to assess fibrotic lesions in mice. RESULTS: Three new lingzhilactones A-C (1-3) containing a fused lactone moiety were isolated from G. lingzhi. We found that 2 could inhibit ROS generation in a dose-dependent manner, inhibit mRNA expression of collagen IV, fibronectin, IL-6 and increase expression of Nrf2 in rat tubular epithelial cells. Furthermore, we found that 2 could reduce urinary albumin levels, abrogate myofibroblastic activation and inhibit the phosphorylation of Smad3 in adriamycin-induced mice. CONCLUSIONS: The in vitro and in vivo results suggested that lingzhilactone B could protect against renal injuries by increasing the activities of antioxidants and inhibiting inflammation. The inhibition of Smad3 phosphorylation suggested that this substance displays in vivo antifibrotic activity by a mechanism that is dependent on disruption of Smad3. These results promote understanding of the traditional usage of G. lingzhi and provide promising findings which may be beneficial for anti-kidney disease drug design.

MicroRNAs in renal fibrosis.

MicroRNAs (miRNAs) are endogenous short non-coding RNAs that regulate most of important cellular processes by inhibiting gene expression through the post-transcriptional repression of their target mRNAs. In kidneys, miRNAs have been associated in renal development, homeostasis, and physiological functions. Results from clinical and experimental animal studies demonstrate that miRNAs play essential roles in the pathogenesis of various renal diseases. Chronic kidney diseases (CKD) is characterized by renal fibrosis. Transforming growth factor beta (TGF-ß) is recognized as a major mediator of renal fibrosis because it is able to stimulate the accumulation of extracellular matrix (ECM) proteins to impair normal kidney function. Recently, emerging evidence demonstrate the relationship between TGF-ß signaling and miRNAs expression during renal diseases. TGF-ß regulates expression of several microRNAs, such as miR-21, miR-192, miR-200, miR-433, and miR-29. MiR-21, miR-192, and miR-433 which are positively induced by TGF-ß signaling play a pathological role in kidney diseases. In contrast, members in both miR-29 and miR-200 families which are inhibited by TGF-ß signaling protect kidneys from renal fibrosis by suppressing the deposition of ECM and preventing epithelial-to-mesenchymal transition, respectively. Clinically, the presence of miRNAs in blood and urine has been examined to be early biomarkers for detecting renal diseases. From experimental animal studies of CKD, targeting microRNAs also provides evidence about therapeutic potential of miRNAs during renal diseases. Now, it comes to the stage to examine the exact mechanisms of miRNAs during the initiation and progression of renal diseases. Therefore, determining the function of miRNAs in renal fibrosis may facilitate the development of both early diagnosis and treatment of renal diseases.

Germ cell nuclear factor regulates gametogenesis in developing gonads.

Expression of germ cell nuclear factor (GCNF; Nr6a1), an orphan member of the nuclear receptor gene family of transcription factors, during gastrulation and neurulation is critical for normal embryogenesis in mice. Gcnf represses the expression of the POU-domain transcription factor Oct4 (Pou5f1) during mouse post-implantation development. Although Gcnf expression is not critical for the embryonic segregation of the germ cell lineage, we found that sexually dimorphic expression of Gcnf in germ cells correlates with the expression of pluripotency-associated genes, such as Oct4, Sox2, and Nanog, as well as the early meiotic marker gene Stra8. To elucidate the role of Gcnf during mouse germ cell differentiation, we generated an ex vivo Gcnf-knockdown model in combination with a regulated CreLox mutation of Gcnf. Lack of Gcnf impairs normal spermatogenesis and oogenesis in vivo, as well as the derivation of germ cells from embryonic stem cells (ESCs) in vitro. Inactivation of the Gcnf gene in vivo leads to loss of repression of Oct4 expression in both male and female gonads.

MicroRNAs in Diabetic Kidney Disease.

Rapid growth of diabetes and diabetic kidney disease exerts a great burden on society. Owing to the lack of effective treatments for diabetic kidney disease, treatment relies on drugs that either reduces its progression or involve renal replacement therapies, such as dialysis and kidney transplantation. It is urgent to search for biomarkers for early diagnosis and effective therapy. The discovery of microRNAs had lead to a new era of post-transcriptional regulators of gene expression. Studies from cells, experimental animal models and patients under diabetic conditions demonstrate that expression patterns of microRNAs are altered during the progression of diabetic kidney disease. Functional studies indicate that the ability of microRNAs to bind 3' untranslated region of messenger RNA not only shows their capability to regulate expression of target genes, but also their therapeutic potential to diabetic kidney disease. The presence of microRNAs in plasma, serum, and urine has been shown to be possible biomarkers in diabetic kidney disease. Therefore, identification of the pathogenic role of microRNAs possesses an important clinical impact in terms of prevention and treatment of progression in diabetic kidney disease because it allows us to design novel and specific therapies and diagnostic tools for diabetic kidney disease.