Single cell genomics has revolutionized our understanding of neuronal cell types. However, scalable technologies for probing single-cell connectivity are lacking, and we are just beginning to understand how molecularly defined cell types are organized into functional circuits. Here, we describe a protocol to generate high-complexity barcoded rabies virus (RV) for scalable circuit mapping from tens of thousands of individual starter cells in parallel.
View Article and Find Full Text PDFStudies in humans and mice have determined that distinct subpopulations of adipocytes reside even within individual adipose tissue depots. Previously, our lab defined three white adipocyte subpopulations with stable and unique gene expression profiles, which were termed type 1, 2, and 3 adipocytes, respectively. Our previous studies demonstrated that type 2 adipocytes were highly responsive to the inflammatory cytokine, tumor necrosis factor alpha (TNFα).
View Article and Find Full Text PDFIn adipose tissue, growth hormone (GH) stimulates lipolysis, leading to an increase in plasma free fatty acid levels and a reduction in insulin sensitivity. In our previous studies, we have found that GH increases lipolysis by reducing peroxisome proliferator-activated receptor γ (PPARγ) transcription activity, leading to a reduction of tat-specific protein 27 (FSP27, also known as CIDEC) expression. In previous studies, our laboratory uncovered 3 developmentally distinct subpopulations of white adipocytes.
View Article and Find Full Text PDFMutations in Dentin Sialophosphoprotein (DSPP) are known to cause, in order of increasing severity, dentin dysplasia type-II (DD-II), dentinogenesis imperfecta type-II (DGI-II), and dentinogenesis imperfecta type-III (DGI-III). DSPP mutations fall into two groups: a 5′-group that affects protein targeting and a 3′-group that shifts translation into the −1 reading frame. Using whole-exome sequence (WES) analyses and Single Molecule Real-Time (SMRT) sequencing, we identified disease-causing DSPP mutations in 12 families.
View Article and Find Full Text PDFOrganic solvent dibenzyl ether (DBE)-based protocols have been widely used in adipose tissue clearing. However, benzyl alcohol/benzyl benzoate (BABB)-based clearing has been shown to offer better transparency in other tissues. The addition of diphenyl ether (DPE) to BABB (BABB-D4) is often included to preserve fluorescent signals, but its effects on adipose tissue transparency and shrinkage have not been explored.
View Article and Find Full Text PDFAim: Since GH stimulates lipolysis in vivo after a 2-hr lag phase, we studied whether this involves GH signaling and gene expression in adipose tissue (AT).
Methods: Human subjects (n = 9) each underwent intravenous exposure to GH versus saline with measurement of serum FFA, and GH signaling, gene array, and protein in AT biopsies after 30-120 min. Human data were corroborated in adipose-specific GH receptor knockout (FaGHRKO) mice versus wild-type mice.
The ability of growth hormone (GH) to induce adipose tissue lipolysis has been known for over five decades; however, the molecular mechanisms that mediate this effect and the ability of GH to inhibit insulin-stimulated glucose uptake have scarcely been documented. In this same time frame, our understanding of adipose tissue has evolved to reveal a complex structure with distinct types of adipocyte, depot-specific differences, a biologically significant extracellular matrix and important endocrine properties mediated by adipokines. All these aforementioned features, in turn, can influence lipolysis.
View Article and Find Full Text PDFObjective: Growth hormone (GH) stimulates lipolysis, but the underlying mechanisms remain incompletely understood. We examined the effect of GH on the expression of lipolytic regulators in adipose tissue (AT).
Methods: In a randomized, placebo-controlled, cross-over study, nine men were examined after injection of 1) a GH bolus and 2) a GH-receptor antagonist (pegvisomant) followed by four AT biopsies.
Over the past decade, great progress has been made in understanding the complexity of adipose tissue biology and its role in metabolism. This includes new insights into the multiple layers of adipose tissue heterogeneity, not only differences between white and brown adipocytes, but also differences in white adipose tissue at the depot level and even heterogeneity of white adipocytes within a single depot. These inter- and intra-depot differences in adipocytes are developmentally programmed and contribute to the wide range of effects observed in disorders with fat excess (overweight/obesity) or fat loss (lipodystrophy).
View Article and Find Full Text PDFAdipose tissue not only stores energy, but also controls metabolism through secretion of hormones, cytokines, proteins, and microRNAs that affect the function of cells and tissues throughout the body. Adipose tissue is organized into discrete depots throughout the body, and these depots are differentially associated with insulin resistance and increased risk of metabolic disease. In addition to energy-dissipating brown and beige adipocytes, recent lineage tracing studies have demonstrated that individual adipose depots are composed of white adipocytes that are derived from distinct precursor populations, giving rise to distinct subpopulations of energy-storing white adipocytes.
View Article and Find Full Text PDFRecent studies suggest that, even within a single adipose depot, there may be distinct subpopulations of adipocytes. To investigate this cellular heterogeneity, we have developed multiple conditionally immortalized clonal preadipocyte lines from white adipose tissue of mice. Analysis of these clones reveals at least three white adipocyte subpopulations.
View Article and Find Full Text PDFGrowth hormone (GH) has long been known to stimulate lipolysis and insulin resistance; however, the molecular mechanisms underlying these effects are unknown. In the present study, we demonstrate that GH acutely induces lipolysis in cultured adipocytes. This effect is secondary to the reduced expression of a negative regulator of lipolysis, fat-specific protein 27 (FSP27; aka Cidec) at both the mRNA and protein levels.
View Article and Find Full Text PDFAm J Physiol Endocrinol Metab
January 2019
Exenatide, a glucagon-like peptide-1 receptor agonist, induces insulin secretion. Its role in insulin clearance has not been adequately examined. Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) promotes hepatic insulin clearance to maintain insulin sensitivity.
View Article and Find Full Text PDFSubcutaneous white adipose tissue (scWAT) is the major fat depot in humans and is a central player in regulating whole body metabolism. Skin exposure to UV wavelengths from sunlight is required for Vitamin D synthesis and pigmentation, although it is plausible that longer visible wavelengths that penetrate the skin may regulate scWAT function. In this regard, we discovered a novel blue light-sensitive current in human scWAT that is mediated by melanopsin coupled to transient receptor potential canonical cation channels.
View Article and Find Full Text PDFis a member of the T-box gene family of mesodermal developmental genes. We have recently shown that Tbx15 plays a critical role in the formation and metabolic programming of glycolytic myofibers in skeletal muscle. is also differentially expressed among white adipose tissue (WAT) in different body depots.
View Article and Find Full Text PDFInsulin receptors (IRs) and IGF-I receptors (IGF-IR) are major regulators of metabolism and cell growth throughout the body; however, their roles in the intestine remain controversial. Here we show that genetic ablation of the IR or IGF-IR in intestinal epithelial cells of mice does not impair intestinal growth or development or the composition of the gut microbiome. However, the loss of IRs alters intestinal epithelial gene expression, especially in pathways related to glucose uptake and metabolism.
View Article and Find Full Text PDFDiabetes strongly impacts protein metabolism, particularly in skeletal muscle. Insulin and IGF-1 enhance muscle protein synthesis through their receptors, but the relative roles of each in muscle proteostasis have not been fully elucidated. Using mice with muscle-specific deletion of the insulin receptor (M-IR-/- mice), the IGF-1 receptor (M-IGF1R-/- mice), or both (MIGIRKO mice), we assessed the relative contributions of IR and IGF1R signaling to muscle proteostasis.
View Article and Find Full Text PDFDermatol Ther (Heidelb)
September 2015
Introduction: Topical 5-fluorouracil (5-FU) has been used to treat actinic keratosis for decades. It has been an important and effective treatment which the patient can self-administer, but is limited by the surface area of skin to be treated (according to the manufacturer's guidelines) of 500 cm(2). Other topical treatments can be painful, or require hospital/health care professional input.
View Article and Find Full Text PDFSkeletal muscle is composed of both slow-twitch oxidative myofibers and fast-twitch glycolytic myofibers that differentially impact muscle metabolism, function and eventually whole-body physiology. Here we show that the mesodermal transcription factor T-box 15 (Tbx15) is highly and specifically expressed in glycolytic myofibers. Ablation of Tbx15 in vivo leads to a decrease in muscle size due to a decrease in the number of glycolytic fibres, associated with a small increase in the number of oxidative fibres.
View Article and Find Full Text PDFPandemic outbreaks of influenza are caused by the emergence of a pathogenic and transmissible virus to which the human population is immunologically naïve. Recent outbreaks of highly pathogenic avian influenza (HPAI) of the H5N1 subtype are of particular concern because of the high mortality rate (60% case fatality rate) and novel subtype. In this study, we have engineered an influenza virus-like particle (VLP) that contains a synthetic, consensus-based HA molecule using a new methodology, computationally optimized broadly reactive antigen (COBRA).
View Article and Find Full Text PDFWhite, beige, and brown adipocytes are developmentally and functionally distinct but often occur mixed together within individual depots. To target white, beige, and brown adipocytes for diagnostic or therapeutic purposes, a better understanding of the cell surface properties of these cell types is essential. Using a combination of in silico, in vitro, and in vivo methods, we have identified three new cell surface markers of adipose cell types.
View Article and Find Full Text PDFHyperhidrosis is a potential cause of severe physical and psychological distress, interfering in activities of daily living. Over the past 100 years, advances have been made regarding the treatment of this debilitating condition with some success. Surgical treatment with sympathectomy was successfully performed for hyperhidrosis in the early part of the 20th century, with various modifications of the technique over the past 100 years.
View Article and Find Full Text PDFmiRNAs are important regulators of biological processes in many tissues, including the differentiation and function of brown and white adipocytes. The endoribonuclease dicer is a major component of the miRNA-processing pathway, and in adipose tissue, levels of dicer have been shown to decrease with age, increase with caloric restriction, and influence stress resistance. Here, we demonstrated that mice with a fat-specific KO of dicer develop a form of lipodystrophy that is characterized by loss of intra-abdominal and subcutaneous white fat, severe insulin resistance, and enlargement and "whitening" of interscapular brown fat.
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