Brown adipose tissue (BAT) is emerging as a target to beat obesity through the dissipation of chemical energy to heat. However, the molecular mechanisms of brown adipocyte thermogenesis remain to be further elucidated. Here, we show that KCTD10, a member of the polymerase delta-interacting protein 1 family, was reduced in BAT by cold stress and a β3 adrenoceptor agonist. Moreover, KCTD10 level increased in the BAT of obese mice, and KCTD10 overexpression attenuates uncoupling protein 1 expression in primary brown adipocytes. BAT-specific KCTD10 knockdown mice had increased thermogenesis and cold tolerance protecting from high-fat diet (HFD)-induced obesity. Conversely, overexpression of KCTD10 in BAT caused reduced thermogenesis, cold intolerance, and obesity. Mechanistically, inhibiting Notch signaling restored the KCTD10 overexpression-suppressed thermogenesis. Our study presents that KCTD10 serves as an upstream regulator of Notch signaling pathway to regulate BAT thermogenesis and whole-body metabolic function.
DNA N6-methyladenine (N6-mA) demethylase Alkbh1 participates in regulating osteogenic differentiation of mesenchymal stem cell (MSCs) and vascular calcification. However, the role of Alkbh1 in bone metabolism remains unclear.Bone marrow mesenchymal stem cells (BMSCs)-specific Alkbh1 knockout mice were used to investigate the role of Alkbh1 in bone metabolism. Western blot, qRT-PCR, and immunofluorescent staining were used to evaluate the expression of Alkbh1 or optineurin (optn). Micro-CT, histomorphometric analysis, and calcein double-labeling assay were used to evaluate bone phenotypes. Cell staining and qRT-PCR were used to evaluate the osteogenic or adipogenic differentiation of BMSCs. Dot blotting was used to detect the level of N6-mA in genomic DNA. Chromatin immunoprecipitation (Chip) assays were used to identify critical targets of Alkbh1. Alkbh1 adeno-associated virus was used to overexpress Alkbh1 in aged mice.Alkbh1 expression in BMSCs declined during aging. Knockout of Alkbh1 promoted adipogenic differentiation of BMSCs while inhibited osteogenic differentiation. BMSC-specific Alkbh1 knockout mice exhibited reduced bone mass and increased marrow adiposity. Mechanistically, we identified optn as the downstream target through which Alkbh1-mediated DNA m6A modification regulated BMSCs fate. Overexpression of Alkbh1 attenuated bone loss and marrow fat accumulation in aged mice.Our findings demonstrated that Alkbh1 regulated BMSCs fate and bone-fat balance during skeletal aging and provided a potential target for the treatment of osteoporosis.
ABSTRACT A distinct taxon of the Drosophila microbiota, Lactobacillus plantarum, is capable of stimulating the generation of reactive oxygen species (ROS) within cells, and inducing epithelial cell proliferation. Here, we show that microbial-induced ROS generation within Drosophila larval stem cell compartments exhibits a distinct spatial distribution. Lactobacilli-induced ROS is strictly excluded from defined midgut compartments that harbor adult midgut progenitor (AMP) cells, forming a functional ‘ROS sheltered zone’ (RSZ). The RSZ is undiscernible in germ-free larvae, but forms following monocolonization with L. plantarum. L. plantarum is a strong activator of the ROS-sensitive CncC/Nrf2 signaling pathway within enterocytes. Enterocyte-specific activation of CncC stimulated the proliferation of AMPs, which demonstrates that pro-proliferative signals are transduced from enterocytes to AMPs. Mechanistically, we show that the cytokine Upd2 is expressed in the gut following L. plantarum colonization in a CncC-dependent fashion, and may function in lactobacilli-induced AMP proliferation and intestinal tissue growth and development.
Background Bladder cancer is one of the most common cancers all over the world. CircZFR is a circular RNA and has been implicated in tumor generation and invasion. However, the exact role of circZFR in the development of bladder cancer (BCa) remains unknown. This study aimed to investigate the function of circZFR in BCa, and further to probe into the association between circ-ZFR, miR-545/miR-1270 and WNT5A. Methods The expression of circZFR in BCa was quantified by qRT-PCR and was positively correlated with the prognosis of BCa patients. Next, the stable knockdown of circZFR BCa cell lines was established and the resulting capacities of proliferation, migration and invasion were measured. The association of circZFR with miR-1270/miR-545 was predicted by circinteractome prediction, and was confirmed by luciferase assay as well as RNA pull down assay. Furthermore, miRNA inhibitors, WNT5A overexpression and Pearson correlation analysis were used to examine the relationship between circZFR, miR-1270/miR-545 and WNT5A. Results The expression of CircZFR was up-regulated both in BCa tissues and in BCa cell lines, and was positively correlated with patient survival rates. Blocking of circZFR’s expression by RNA inhibitors suppressed the proliferation, migration and invasion of BCa cells both in vitro and in vivo . On the other hand, overexpression of target miRNA supported that circZFR directly interact with miR-545 and miR-1270. Moreover, we demonstrated that circZFR promotes the progression of BCa by upregulating WNT5A’s expression via sponging miR-545 and miR-1270. Conclusions CircZFR promotes the proliferation, migration and invasion of BCa cells by upregulating WNT5A signaling pathway via sponging miR-545 and miR-1270. These results provide new insights into the molecular mechanism of circZFR in BCa progression, and more important, a novel target for BCa clinical treatment.
The β-galactoside binding lectins, termed galectins, have garnered immense scientific interest for their ability to regulate diverse biologic processes, from adaptive immune responses to epithelial cell biology. Yet, an understanding of the role of galectins in regulating developmental processes has been limited by the functional redundancies across galectins which exist in vertebrates. Thus, we utilized the model organism Drosophila, which contains a single galectin ortholog, to ask what are the developmental requirements for galectins in metazoans. Using CRISPR/Cas9, we generated deletions in the galectin locus which efficiently eliminated galectin protein (Dmgal) across tissues. Intriguing, loss of galectin is not essential in Drosophila as animals ecclose with relatively minimal phenotypes. Among these, dmgal-deficient animals are significantly smaller than their wild-type counterparts. Moreover, when challenged to nutrient-deprivation or Paraquat-toxicity, dmgal-deficient animals show marked sensitivity compared to their wild-type animals. Transcriptomics analysis reveals that dmgal-deficient animals show significantly different profiles than their wild-type counterparts, with enrichment in metabolic pathways. Similarly, metabolomics shows distinct profiles from dmgal-deficient and wild-type animals with significant alterations in amino acid and nutrient-sensing pathways. Finally, analysis of the Drosophila fat body reveals alterations in fat content, and tissue specific deletion of galectin in this organ renders animals sensitive to nutrient loss. Taken together, these findings uncover a novel role for dmgal in regulating Drosophila metabolism in the Drosophila fat body, and may provide clues into the role of galectins in regulating insulin sensitivity and NASH/NAFLD in vertebrates.
The heart develops under reduced and varying oxygen concentrations, yet there is little understanding of oxygen metabolism in the normal and mal-development of the heart. Here we used a novel reagent, the ODD-Luc hypoxia reporter mouse (oxygen degradation domain, ODD) of Hif-1α fused to Luciferase (Luc), to assay the activity of the oxygen sensor, prolyl hydroxylase, and oxygen reserve, in the developing heart. We tested the role of hypoxia-dependent responses in heart development by targeted inactivation of Hif-1α.ODD-Luciferase activity was 14-fold higher in mouse embryonic day 10.5 (E10.5) versus adult heart and liver tissue lysates. ODD-Luc activity decreased in 2 stages, the first corresponding with the formation of a functional cardiovascular system for oxygen delivery at E15.5, and the second after birth consistent with complete oxygenation of the blood and tissues. Reduction of maternal inspired oxygen to 8% for 4 hours caused minimal induction of luciferase activity in the maternal tissues but robust induction in the embryonic tissues in proportion to the basal activity, indicating a lack of oxygen reserve, and corresponding induction of a hypoxia-dependent gene program. Bioluminescent imaging of intact embryos demonstrated highest activity in the outflow portion of the E13.5 heart. Hif-1α inactivation or prolonged hypoxia caused outflow and septation defects only when targeted to this specific developmental window.Low oxygen concentrations and lack of oxygen reserve during a critical phase of heart organogenesis may provide a basis for vulnerability to the development of common septation and conotruncal heart defects.
The enteric pathogen Salmonella typhimurium suppresses host innate immune responses via secretion of preformed effector proteins into host cells during invasion. One of these proteins, AvrA, has potent immunosuppressive and anti‐apoptotic effects in mammalian cultured cells and in a Drosophila animal model via inhibition of the JNK pathway. To study the role of AvrA in a murine model of natural infection, wild type Salmonella harboring AvrA or an isogenic AvrA null mutant Salmonella were orally administered to mice pretreated with streptomycin and infectious phenotypes compared. Infection with the AvrA null Salmonella caused increased levels of apoptosis in the cecal epithelium and in lymphoid resident monocytic cells at 6h post infection. Additionally, the AvrA null Salmonella induced increased serum cytokine levels, including KC, IL‐1beta and TNFalpha. Furthermore, AvrA null Salmonella caused increased hepatosplenomegaly by 7 days post infection. This coincided with increased bacterial load in the liver, spleen and mesenteric lymph node, and more severe weight loss. We conclude that Salmonella evades host innate immunity and gains systemic access/dissemination via AvrA mediated inhibition of cytokine production and apoptosis. Research funding provided by NIH AI 64462.
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