-
European Journal of Internal Medicine Sep 2021High body mass index (BMI) is known to be associated with elevated blood pressure (BP). The present study aims to determine the relative importance of the two components...
High body mass index (BMI) is known to be associated with elevated blood pressure (BP). The present study aims to determine the relative importance of the two components of BMI, fat mass and lean body mass index, on BP levels. We assessed body composition with bioimpedance and performed 24 hour ambulatory BP measurements in 534 individuals (mean age 61 ± 3 years) who had no cardiovascular medication. Fat mass index and lean mass index were calculated analogously to BMI as fat mass or lean body mass (kg) divided by the square of height (m). Both fat mass index and lean mass index showed a positive, small to moderate relationship with all 24 hour BP components independently of age, sex, smoking, and leisure-time physical activity. There were no interaction effects between fat mass index and lean mass index on the mean BP levels. Adult lean body mass is a significant determinant of BP levels with an equal, albeit small to moderate magnitude as fat mass. Relatively high amount of muscle mass may not be beneficial to cardiovascular health.
Topics: Adult; Animals; Blood Pressure; Body Composition; Body Mass Index; Fat Body; Humans; Middle Aged
PubMed: 33994250
DOI: 10.1016/j.ejim.2021.04.025 -
Current Opinion in Cell Biology Jun 2016Aging is characterized by a progressive loss of tissue function and an increased susceptibility to injury and disease. Many age-associated pathologies manifest an... (Review)
Review
Aging is characterized by a progressive loss of tissue function and an increased susceptibility to injury and disease. Many age-associated pathologies manifest an inflammatory component, and this has led to the speculation that aging is at least in part caused by some form of inflammation. However, whether or not inflammation is truly a cause of aging, or is a consequence of the aging process is unknown. Recent work using Drosophila has uncovered a mechanism where the progressive loss of lamin-B in the fat body upon aging triggers systemic inflammation. This inflammatory response perturbs the local immune response of the neighboring gut tissue and leads to hyperplasia. Here, we will discuss the literature connecting lamins to aging and inflammation.
Topics: Aging; Animals; Drosophila; Fat Body; Humans; Inflammation; Lamin Type B
PubMed: 27023494
DOI: 10.1016/j.ceb.2016.03.004 -
Lipids in Health and Disease Apr 2014The fat body in invertebrates was shown to participate in energy storage and homeostasis, apart from its other roles in immune mediation and protein synthesis to mention... (Review)
Review
The fat body in invertebrates was shown to participate in energy storage and homeostasis, apart from its other roles in immune mediation and protein synthesis to mention a few. Thus, sharing similar characteristics with the liver and adipose tissues in vertebrates. However, vertebrate adipose tissue or fat has been incriminated in the pathophysiology of metabolic disorders due to its role in production of pro-inflammatory cytokines. This has not been reported in the insect fat body. The link between the fat body and adipose tissue was examined in this review with the aim of determining the principal factors responsible for resistance to inflammation in the insect fat body. This could be the missing link in the prevention of metabolic disorders in vertebrates, occasioned by obesity.
Topics: Adipose Tissue; Animals; Fat Body; Invertebrates; Metabolic Syndrome; Vertebrates
PubMed: 24758278
DOI: 10.1186/1476-511X-13-71 -
Frontiers in Cellular and Infection... 2022The protozoan parasite spp. invades into tick oocytes and remains in the offspring. The transovarial transmission phenomenon of in ticks has been demonstrated...
The protozoan parasite spp. invades into tick oocytes and remains in the offspring. The transovarial transmission phenomenon of in ticks has been demonstrated experimentally, but the molecular mechanisms remain unclear. invasion into oocytes occurs along with the progression of oogenesis. In the present study, to find the key tick factor(s) for transmission, we focused on molecules involved in yolk protein precursor (vitellogenin, Vg) synthesis and Vg uptake, which are crucial events in tick oogenesis. With a tick- experimental model, the expression profiles of , , , , and , Vg synthesis-related genes, and Vg receptor () and autophagy-related gene 6 (), Vg uptake-related genes, were analyzed using real-time PCR using tissues collected during the preovipositional period in -infected ticks. The expression levels of () and decreased in the fat body of -infected ticks 1 day after engorgement. In the ovary, mRNA expression was significantly higher in -infected ticks than in uninfected ticks 1 and 2 days after engorgement and decreased 3 days after engorgement. expression was significantly lower in -infected ticks than in uninfected ticks 2 and 4 days after engorgement. had a lower gene expression in -infected ticks compared to uninfected ticks 2 days after engorgement. Additionally, western blot analysis using protein extracts from each collected tissue revealed that Vg-2 (HlVg-2) accumulate in the fat body and hemolymph of -infected ticks. These results suggest that Vg uptake from the hemolymph to the ovary was suppressed in the presence of . Moreover, knockdown ticks had a lower detection rate of DNA in the ovary and a significant reduction of DNA in the hemolymph compared with control ticks. Taken together, our results suggest that accumulated HlVg-2 is associated with infection or transmission in the tick body. These findings, besides previous reports on VgR, provide important information to elucidate the transovarial transmission mechanisms of pathogens in tick vectors.
Topics: Animals; Babesia; DNA; Fat Body; Female; Hemolymph; Ixodidae; Vitellogenins
PubMed: 35800383
DOI: 10.3389/fcimb.2022.908142 -
ELife Sep 2023Obesity induced by high-fat diet (HFD) is a multi-factorial disease including genetic, physiological, behavioral, and environmental components. has emerged as an...
Obesity induced by high-fat diet (HFD) is a multi-factorial disease including genetic, physiological, behavioral, and environmental components. has emerged as an effective metabolic disease model. Cytidine 5'-triphosphate synthase (CTPS) is an important enzyme for the de novo synthesis of CTP, governing the cellular level of CTP and the rate of phospholipid synthesis. CTPS is known to form filamentous structures called cytoophidia, which are found in bacteria, archaea, and eukaryotes. Our study demonstrates that CTPS is crucial in regulating body weight and starvation resistance in by functioning in the fat body. HFD-induced obesity leads to increased transcription of CTPS and elongates cytoophidia in larval adipocytes. Depleting CTPS in the fat body prevented HFD-induced obesity, including body weight gain, adipocyte expansion, and lipid accumulation, by inhibiting the PI3K-Akt-SREBP axis. Furthermore, a dominant-negative form of CTPS also prevented adipocyte expansion and downregulated lipogenic genes. These findings not only establish a functional link between CTPS and lipid homeostasis but also highlight the potential role of CTPS manipulation in the treatment of HFD-induced obesity.
Topics: Animals; Diet, High-Fat; Fat Body; Phosphatidylinositol 3-Kinases; Obesity; Body Weight; Drosophila; Lipids
PubMed: 37695169
DOI: 10.7554/eLife.85293 -
ELife May 2023Defective nutrient storage and adipocyte enlargement (hypertrophy) are emerging features of metabolic syndrome and type 2 diabetes. Within adipose tissues, how the...
Defective nutrient storage and adipocyte enlargement (hypertrophy) are emerging features of metabolic syndrome and type 2 diabetes. Within adipose tissues, how the cytoskeletal network contributes to adipose cell size, nutrient uptake, fat storage, and signaling remain poorly understood. Utilizing the larval fat body (FB) as a model adipose tissue, we show that a specific actin isoform-Act5C-forms the cortical actin network necessary to expand adipocyte cell size for biomass storage in development. Additionally, we uncover a non-canonical role for the cortical actin cytoskeleton in inter-organ lipid trafficking. We find Act5C localizes to the FB cell surface and cell-cell boundaries, where it intimately contacts peripheral LDs (pLDs), forming a cortical actin network for cell architectural support. FB-specific loss of Act5C perturbs FB triglyceride (TG) storage and LD morphology, resulting in developmentally delayed larvae that fail to develop into flies. Utilizing temporal RNAi-depletion approaches, we reveal that Act5C is indispensable post-embryogenesis during larval feeding as FB cells expand and store fat. Act5C-deficient FBs fail to grow, leading to lipodystrophic larvae unable to accrue sufficient biomass for complete metamorphosis. In line with this, Act5C-deficient larvae display blunted insulin signaling and reduced feeding. Mechanistically, we also show this diminished signaling correlates with decreased lipophorin (Lpp) lipoprotein-mediated lipid trafficking, and find Act5C is required for Lpp secretion from the FB for lipid transport. Collectively, we propose that the Act5C-dependent cortical actin network of adipose tissue is required for adipose tissue size-expansion and organismal energy homeostasis in development, and plays an essential role in inter-organ nutrient transport and signaling.
Topics: Animals; Actins; Adipocytes; Adipose Tissue; Diabetes Mellitus, Type 2; Drosophila; Fat Body; Lipids; Nutrients
PubMed: 37144872
DOI: 10.7554/eLife.81170 -
International Journal of Molecular... Sep 2021The evolutionarily conserved c-Jun N-terminal kinase (JNK) signaling pathway is a critical genetic determinant in the control of longevity. In response to extrinsic and... (Review)
Review
The evolutionarily conserved c-Jun N-terminal kinase (JNK) signaling pathway is a critical genetic determinant in the control of longevity. In response to extrinsic and intrinsic stresses, JNK signaling is activated to protect cells from stress damage and promote survival. In , global JNK upregulation can delay aging and extend lifespan, whereas tissue/organ-specific manipulation of JNK signaling impacts lifespan in a context-dependent manner. In this review, focusing on several tissues/organs that are highly associated with age-related diseases-including metabolic organs (intestine and fat body), neurons, and muscles-we summarize the distinct effects of tissue/organ-specific JNK signaling on aging and lifespan. We also highlight recent progress in elucidating the molecular mechanisms underlying the tissue-specific effects of JNK activity. Together, these studies highlight an important and comprehensive role for JNK signaling in the regulation of longevity in .
Topics: Aging; Animals; Brain; Drosophila Proteins; Drosophila melanogaster; Fat Body; JNK Mitogen-Activated Protein Kinases; Longevity; MAP Kinase Signaling System; Models, Biological; Neurons
PubMed: 34502551
DOI: 10.3390/ijms22179649 -
Proceedings of the National Academy of... Apr 2022Zinc deficiency is commonly attributed to inadequate absorption of the metal. Instead, we show that body zinc stores in Drosophila melanogaster depend on tryptophan...
Zinc deficiency is commonly attributed to inadequate absorption of the metal. Instead, we show that body zinc stores in Drosophila melanogaster depend on tryptophan consumption. Hence, a dietary amino acid regulates zinc status of the whole insect—a finding consistent with the widespread requirement of zinc as a protein cofactor. Specifically, the tryptophan metabolite kynurenine is released from insect fat bodies and induces the formation of zinc storage granules in Malpighian tubules, where 3-hydroxykynurenine and xanthurenic acid act as endogenous zinc chelators. Kynurenine functions as a peripheral zinc-regulating hormone and is converted into a 3-hydroxykynurenine–zinc–chloride complex, precipitating within the storage granules. Thus, zinc and the kynurenine pathway—well-known modulators of immunity, blood pressure, aging, and neurodegeneration—are physiologically connected.
Topics: Animals; Drosophila melanogaster; Fat Body; Kynurenine; Malpighian Tubules; Tryptophan; Zinc
PubMed: 35412912
DOI: 10.1073/pnas.2117807119 -
Annual Review of Entomology 2010The fat body plays major roles in the life of insects. It is a dynamic tissue involved in multiple metabolic functions. One of these functions is to store and release... (Review)
Review
The fat body plays major roles in the life of insects. It is a dynamic tissue involved in multiple metabolic functions. One of these functions is to store and release energy in response to the energy demands of the insect. Insects store energy reserves in the form of glycogen and triglycerides in the adipocytes, the main fat body cell. Insect adipocytes can store a great amount of lipid reserves as cytoplasmic lipid droplets. Lipid metabolism is essential for growth and reproduction and provides energy needed during extended nonfeeding periods. This review focuses on energy storage and release and summarizes current understanding of the mechanisms underlying these processes in insects.
Topics: Animals; Carbohydrate Metabolism; Energy Metabolism; Fat Body; Insect Hormones; Insecta; Lipid Metabolism; Oligopeptides; Pyrrolidonecarboxylic Acid
PubMed: 19725772
DOI: 10.1146/annurev-ento-112408-085356 -
The FEBS Journal Jul 2021Organisms have constant contact with potentially harmful agents that can compromise their fitness. However, most of the times these agents fail to cause serious disease... (Review)
Review
Organisms have constant contact with potentially harmful agents that can compromise their fitness. However, most of the times these agents fail to cause serious disease by virtue of the rapid and efficient immune responses elicited in the host that can range from behavioural adaptations to immune system triggering. The immune system of insects does not comprise the adaptive arm, making it less complex than that of vertebrates, but key aspects of the activation and regulation of innate immunity are conserved across different phyla. This is the case for the hormonal regulation of immunity as a part of the broad organismal responses to external conditions under different internal states. In insects, depending on the physiological circumstances, distinct hormones either enhance or suppress the immune response integrating individual (and often collective) responses physiologically and behaviourally. In this review, we provide an overview of our current knowledge on the endocrine regulation of immunity in insects, its mechanisms and implications on metabolic adaptation and behaviour. We highlight the importance of this multilayered regulation of immunity in survival and reproduction (fitness) and its dependence on the hormonal integration with other mechanisms and life-history traits.
Topics: Adaptation, Physiological; Animals; Endocrine Cells; Fat Body; Hemocytes; Immunity, Cellular; Immunity, Innate; Insecta; Juvenile Hormones; Pore Forming Cytotoxic Proteins
PubMed: 33021015
DOI: 10.1111/febs.15581