Signaling Robert H. Lustig, MD, MSL, Professor of Pediatrics, University of California, San Francisco, CA and Alejandro Gugliucci, MD, PhD, Professor of Biochemistry and Associate Dean of Research, Touro University-California, Vallejo, CA | Bio-Techne, 614 McKinley Place NE, Minneapolis, MN 55413

What is Metabolic Syndrome? Hypothalamus BRAIN LEPTIN INSULIN Brain, NPY: MAB8517 LEPR Brain, NPY RNAscope® SYSTEMIC BLOOD A constellation of pathophysiological findings IR linking ectopic fat deposition, inflammation, PVN DIAGNOSTIC OTHER BIOMARKERS STRESS Neuron JAK2 insulin resistance, and liver dysfunction with IRS-2 IRS-2 CRITERIA defective and lipid trafficking. , Non-alcoholic Fatty Liver Disease, Adrenal Cortisol Cortex GABA R A STAT3 are some of the – Leptin – GSK3β resultant conditions associated with the Hypothalamus RESTING GABA + POMC PI3K Ghrelin MC4R ENERGY Y R Neuron Palmitate (FFA) Cortisol syndrome. The three primary drivers of the Amygdala VAT EXPENDITURE 1 PKC Cholesterol NPY Glucose IL-6 syndrome are: 1) subcutaneous fat (); α-MSH P STAT3 PIP3 Locus Coeruleus Pituitary Fat AgRP Insulin TNF-α Resistin 2) visceral fat (stress); and 3) hepatic fat P STAT3 SOCS3 VLDL/TG ACTH LDL/sdLDL Visfatin (diet). PHYSICAL VAGUS PDK1 Leptin normally Uric Acid L-lactate ACTIVITY OREXIGENESIS ANOREXIGENESIS D-lactate reduces appetite SQFAT LPS by decreasing vagal Insulin Nucleus FOXO1 AKT Fibrinogen tone and promotes Secretion LEGEND APPETITE PAI-1 energy expenditure by ANGPTL-3 Insulin NPY-AgRP P STAT3 increasing sympathetic Resistance Neuron FOXO1 Apo C-III P P STAT3 SOCS3 Phosphorylation tone. However, VMH TMAO hyperinsulinemia VTA Insulin GABA POMC HDL ALT + Activation/Induction/Stimulation STARVATION ATP promotes CNS leptin Neuron + AgRP K LEPR Mitochondria – resistance, resulting in REWARD – Inhibition Sympathetic NPY K increased food intake and NUCLEUS – GHS-R ARC Neurons ATP SQ Nervous Leptin + Multi-step Process reduced expenditure ACCUMBENS IR FAT System GHS-R driving greater energy – Adiponectin Stomach LEPR Systemic Circulation deposition. Stress Insulin Ghrelin + Ghrelin IR + increases sympathetic tone Portal Circulation Leptin Pancreas mV and cortisol, which Insulin Kinase chronically results in Leptin t inhibition of lipolysis in Transcriptional Regulator visceral adipocytes. ANATOMY HYPOTHALAMIC CIRCUITRY BIOCHEMISTRY/NEUROPHYSIOLOGY Other

Liver, CD36/FAT: NB400-101

Visceral adipose tissue VISCERAL FAT Glucose is normally LIVER PANCREAS Insulin release is (VAT) is acutely stored as glycogen. under tripartite responsive to However, fructose is control: a) glucose Fat, PLIN1: NB110-40760 White Visceral Adipocyte FFA adrenergic innervation shunted to the Portal Blood rise; b) vagus VLDL Apo CII which activates Glycerol mitochondria, which Efferent nerve; and c) CD36/FAT AQP7 CD36/FAT β-Cell vagus hormone-sensitive become overwhelmed, FFA Uric Acid nerve intestinal GLP-1. lipase (HSL) to promote with resultant shuttling AMP Uric Acid Each of these PP2A Steatosis Depolarization lipolysis. Under chronic Chylomicron of citrate into the KHK 2+ SUR1 factors is increased GLUT4 Aldolase Lipid Droplets Ca stress conditions, Glucose cytosol. This results in Fructose GLUT2 Fructose F-1-P GA ACh in response to poor Glucose MG AMPK Ectopic Fat KATP Glucose DHAP cortisol increases NPY GLUT de novo lipogenesis, ATP Ceramide Ca 1.3 diet, driving LPL ANGPTL4,3,8 ChREBP v FFA Sorbitol V production and release PPAR * SREBP1a Translocation unrelated to insulin D-lactate SREBP1c m M hyperinsulinemia γ IR + 3 from adrenergic G-3-P levels. Fat will either be K + and increased fat Portal Blood AR Palmitoyl-CoA Na synapses. Activation of HSL P -Tyr exported out as VLDL storage into Glucose G-6-P F-1,6-BP GA-3-P GA-3-P PLIN1 Glycerol IRS-1 FAS the Y2 receptors PKA promoting GCK subcutaneous and MAGL FOXO1 FOXO1P AKT FFA AdipoR AcCoA ACC1 DAG inhibits lipolysis and DAG Efferent atherogenesis or result ATP visceral fat. Malonyl-CoA allows lipogenesis. Sympathetic Gs vagus in liver fat droplets P -Ser α7nAChR IR P -Tyr OAA ACL innervation ATGL nerve ER When the visceral AR IRS-1 which contribute to IRS-1 Citrate TAG β3 cAMP 2+ G-6-P adipocyte becomes hepatic insulin FOXO1 VLDL VLDL Insulin Ca NE Pyruvate Citrate MTP insulin resistant, MAG resistance. Ceramide shuttle Insulin TAG P -Ser CPT1 disinhibition of HSL Gi NFκB and IL-6 inhibit AKT to IL6-R AKT P FOXO1 AcCoA ApoB-100 GCK GLUT2 Glucose NPY JNK2 SOCS1/3 IRS-1 leads to palmitate/FFA Y R foment hepatic insulin 2+ 2 TBK1 Citrate Ca OAA TCA Hypertri- efflux into the portal Lipid Droplet CD36/FAT resistance, resulting in Glucose Cycle IP R TNFα Glucose Gluconeogenesis β-oxidation glyceridemia, 3 circulation, leading to IKKα increased hepatic atherogenic hepatic uptake, hepatic PDE3B glucose output and NOX Increase hepatic profile LDL, PKA MARCKS IKKδ AMPK HIFα glucose output Mitochondria small insulin resistance, and CREB hyperglycemia. The dense KLF5 O TMA FMO LDL fatty liver. IL-6 efflux 2 effect is compounded by PKC Pancreas, Insulin: MAB8056 C/EBPβ NIK RAGE C/EBP IL-6 TMAO ATP cAMP IP into the portal system α excessive palmitate/free AGEs ER 3 Cortisol C/EBPδ USF2 β-oxidation TNFR Endothelial Cells DAG activates hepatic USF1 fatty acids (FFA) coming AC GR PKCε NADPH oxidase (NOX) TAG from subcutaneous and GLP-1R G PIP HDAC9 TNF i 2 PLC resulting in ROS PKC IL-6 Synthesis α visceral fat due to FFA Mitochondria JNK1 ROS UPR α2AR production. Visceral fat insulin resistance in TNFR TLR4 TNFα TRAF2 IKKβ MKK1 NFkβ M contains four-fold adipocytes. Peripheral Lipid peroxidation, 3 M1 Macrophage HIFα protein denaturation more “crown-like inflammatory mediators e.g. lower IRS-1 NE NFκB synthesis ACh structures” that export LPS RAGE (AGEs, LPS, FFA, LPS TLR4 TRAF6 GLP-1 inflammatory TNF-alpha) act on JNK-1 Sympathetic innervation Efferent vagus nerve mediators directly to IL-6 JNK1 to generate reactive the liver. PPARγ Lipolysis TAG Synthesis Preadipocyte to adipocyte differentiation TLR4 IKKβ oxygen species (ROS), which cause cellular damage.

Increased Muscle, GLUT4: NBP2-44299 SKELETAL MUSCLE Intestinal dysbiosis GUT SUBCUTANEOUS FAT Subcutaneous (SQ) blood-borne glucose due to poor diet or fat is responsive to and fatty acids INSULIN antibiotics results in vagal innervation IR Macrophage, TLR4: MAB2759 cannot be cleared by CD36/FAT lipopolysaccharide White Subcutaneous Adipocyte and skeletal muscle due (LPS) production. Enterocyte FFA hyperinsulinemia, Apo CII to insulin resistance LPS enters the Glycerol which both activate IRS-1 GLUT2 Fructose VLDL and reduction in portal circulation CD36/FAT AQP7 Chylomicron lipoprotein lipase to PKCθ GLUT4 translocation, PI3K Ectopic Fat due to breakdown drive energy from Fructose GLUT5 which compounds the PKCζ FFA in zonulins with Fructose F-1-P Trioses AcCoA Glucose circulating VLDL and hyperglycemia. resultant “leaky Dysbiosis KHK FFA Glucose GLUT4 chylomicrons into fat Glycogen Zonulin gut”, promoting (Diet/Antibiotics) LPL vacuoles to promote ATP ADP + ADP G-3-P ApoB48 GLUT ANGPTL4,3,8 hepatocyte EGFR FFA fat storage in DAG TAG * Translocation IR inflammation and G-3-P PPARγ SREBP1a vesicles. When cells GSK3 AKT P -Tyr hepatic insulin Firmicutes/ Bacteroides HSL become hypoxic and Ceramides PDK1 AMP Chylomicron Sympathetic IRS-1 Acyl-Carnitines resistance. In PLIN1 Glycerol die, fat tissue is Gram+/- innervation PKA PI3K FFA Acyl-CoA addition, lack of IMP Uric Acid MAGL FOXO1 FOXO1P AKT infiltrated with Lymph DAG P -Ser Efferent results bacilli 7nAChR macrophages in IRS-1 α vagus GS mTORC1 in decreased and cocci NE Gs PKB nerve “crown-like AS160 DRP1 ZOs ATGL short-chain fatty Uric Acid Leptin structures” that Choline β3AR cAMP JAMs Portal Blood MAG PDE3B Glucose acids(SCFA). An LPS LPS mTOR promote more increase in bile TAG insulin resistance ROS TMA 4EBP1 S6K1 DRP1 acid hydrolase NFκB JNK2 through TNF-alpha. Enterocyte Leptin Glucose GLUT4 MFN2 leads to a reduction Adiponectin Adipocyte insulin GLUT TMA Lipid Droplet TBK1 Adiponectin Translocation Mitochondrial in glucagon-like resistance disinhibits Fission HIFα eIF-4E eEF2K eIF-4B S6 peptide-1 (GLP-1), PDE3B IKKα hormone-sensitive Mitochondrial inflammation and Bile Salt Hydrolase Bile Acids AMPK lipase (HSL) leading Glucose Fusion CD36/FAT PGC-1α impaired insulin (Taurocholic acid/Glycocholic acid) to palmitate/FFA β-oxidation secretion. IKKε NIK O Endothelial Cells release into the ROS L-cell 2 Glycolysis Krebs cycle Fiber SCFA TNFR systemic circulation, TGR5 β-oxidation AMPK which results in AcCoA ATP AMP/ATP TNFα Gs Protein Bile Acids FXR GLP-1 GLP-1 FFA TAG hepatic inflammation CO2 AR UCP-3 Synthesis Synthesis Mitochondria and insulin β 2 Cholic acid Glucolysis Mitochondria Colon, E-Cadherin, MAB1838 TLR4 resistance. Cell Sympathetic Thermogenesis innervation NE SCFA GPCR41 HIFα death leads to LPS NFκB reduction in RAGE adiponectin, which M1 Macrophage further promotes JNK1 hepatic insulin TLR4 IKKβ resistance.