ABSTRACT
Activating brown adipose tissue (BAT) improves systemic metabolism, making it a promising target for metabolic syndrome. BAT is activated by 12,13-dihydroxy-9Z-octadecenoic acid (12,13-diHOME), which we previously identified to be inversely associated with BMI and which directly improves metabolism in multiple tissues. Here we profile plasma lipidomics from 83 people and test which lipids' association with BMI replicates in a concordant direction using our novel tool ScreenDMT, whose power and validity we demonstrate via mathematical proofs and simulations. We find that the linoleic acid diols 12,13-diHOME and 9,10-diHOME are both replicably inversely associated with BMI and mechanistically activate calcium influx in mouse brown and white adipocytes in vitro, which implicates this signaling pathway and 9,10-diHOME as candidate therapeutic targets. ScreenDMT can be applied to test directional mediation, directional replication, and qualitative interactions, such as identifying biomarkers whose association is shared (replication) or opposite (qualitative interaction) across diverse populations.
Subject(s)
Body Mass Index , Calcium , Animals , Mice , Humans , Calcium/metabolism , Male , Adipocytes/metabolism , Female , Adipose Tissue, Brown/metabolism , LipidomicsABSTRACT
OBJECTIVE: We aimed to identify metabolites associated with loss of glycemic control in youth-onset type 2 diabetes. RESEARCH DESIGN AND METHODS: We measured 480 metabolites in fasting plasma samples from the TODAY (Treatment Options for Type 2 Diabetes in Adolescents and Youth) study. Participants (N = 393; age 10-17 years) were randomly assigned to metformin, metformin plus rosiglitazone, or metformin plus lifestyle intervention. Additional metabolomic measurements after 36 months were obtained in 304 participants. Cox models were used to assess baseline metabolites, interaction of metabolites and treatment group, and change in metabolites (0-36 months), with loss of glycemic control adjusted for age, sex, race, treatment group, and BMI. Metabolite prediction models of glycemic failure were generated using elastic net regression and compared with clinical risk factors. RESULTS: Loss of glycemic control (HbA1c ≥8% or insulin therapy) occurred in 179 of 393 participants (mean 12.4 months). Baseline levels of 33 metabolites were associated with loss of glycemic control (q < 0.05). Associations of hexose and xanthurenic acid with treatment failure differed by treatment randomization; youths with higher baseline levels of these two compounds had a lower risk of treatment failure with metformin alone. For three metabolites, changes from 0 to 36 months were associated with loss of glycemic control (q < 0.05). Changes in d-gluconic acid and 1,5-AG/1-deoxyglucose, but not baseline levels of measured metabolites, predicted treatment failure better than changes in HbA1c or measures of ß-cell function. CONCLUSIONS: Metabolomics provides insight into circulating small molecules associated with loss of glycemic control and may highlight metabolic pathways contributing to treatment failure in youth-onset diabetes.
Subject(s)
Biomarkers , Diabetes Mellitus, Type 2 , Hypoglycemic Agents , Metformin , Humans , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/metabolism , Male , Female , Adolescent , Metformin/therapeutic use , Child , Biomarkers/blood , Hypoglycemic Agents/therapeutic use , Glycemic Control , Blood Glucose/metabolism , Rosiglitazone/therapeutic use , Glycated Hemoglobin/metabolismABSTRACT
Wound research has typically been performed without regard for where the wounds are located on the body, despite well-known heterogeneities in physical and biological properties between different skin areas. The skin covering the palms and soles is highly specialized, and plantar ulcers are one of the most challenging and costly wound types to manage. Using primarily the porcine model, we show that plantar skin is molecularly and functionally more distinct from nonplantar skin than previously recognized, with unique gene and protein expression profiles, broad alterations in cellular functions, constitutive activation of many wound-associated phenotypes, and inherently delayed healing. This unusual physiology is likely to play a significant but underappreciated role in the pathogenesis of plantar ulcers as well as the last 25+ years of futility in therapy development efforts. By revealing this critical yet unrecognized pitfall, we hope to contribute to the development of more effective therapies for these devastating nonhealing wounds.
Subject(s)
Phenotype , Skin , Wound Healing , Animals , Wound Healing/physiology , Swine , Skin/pathology , Skin/injuries , Skin/metabolism , Disease Models, Animal , Foot Ulcer/physiopathology , Foot Ulcer/pathology , Humans , Female , Skin Physiological Phenomena , FootABSTRACT
Pancreatic ß cells are specialized for coupling glucose metabolism to insulin peptide production and secretion. Acute glucose exposure robustly and coordinately increases translation of proinsulin and proteins required for secretion of mature insulin peptide. By contrast, chronically elevated glucose levels that occur during diabetes impair ß cell insulin secretion and have been shown experimentally to suppress insulin translation. Whether translation of other genes critical for insulin secretion is similarly downregulated by chronic high glucose is unknown. Here, we used high-throughput ribosome profiling and nascent proteomics in MIN6 insulinoma cells to elucidate the genome-wide impact of sustained high glucose on ß cell mRNA translation. Before induction of ER stress or suppression of global translation, sustained high glucose suppressed glucose-stimulated insulin secretion and downregulated translation of not only insulin, but also mRNAs related to insulin secretory granule formation, exocytosis, and metabolism-coupled insulin secretion. Translation of these mRNAs was also downregulated in primary rat and human islets following ex vivo incubation with sustained high glucose and in an in vivo model of chronic mild hyperglycemia. Furthermore, translational downregulation decreased cellular abundance of these proteins. Our study uncovered a translational regulatory circuit during ß cell glucose toxicity that impairs expression of proteins with critical roles in ß cell function.
Subject(s)
Hyperglycemia , Insulin-Secreting Cells , Islets of Langerhans , Pancreatic Neoplasms , Rats , Humans , Animals , Insulin Secretion , RNA, Messenger/metabolism , Insulin/metabolism , Hyperglycemia/genetics , Hyperglycemia/metabolism , Glucose/metabolism , Insulin-Secreting Cells/metabolism , Peptides/metabolism , Pancreatic Neoplasms/metabolism , Islets of Langerhans/metabolismABSTRACT
Pancreatic ß-cells are specialized for coupling glucose metabolism to insulin peptide production and secretion. Acute glucose exposure robustly and coordinately increases translation of proinsulin and proteins required for secretion of mature insulin peptide. By contrast, chronically elevated glucose levels that occur during diabetes impair ß-cell insulin secretion and have been shown experimentally to suppress insulin translation. Whether translation of other genes critical for insulin secretion are similarly downregulated by chronic high glucose is unknown. Here, we used high-throughput ribosome profiling and nascent proteomics in MIN6 insulinoma cells to elucidate the genome-wide impact of sustained high glucose on ß-cell mRNA translation. Prior to induction of ER stress or suppression of global translation, sustained high glucose suppressed glucose-stimulated insulin secretion and downregulated translation of not only insulin, but also of mRNAs related to insulin secretory granule formation, exocytosis, and metabolism-coupled insulin secretion. Translation of these mRNAs was also downregulated in primary rat and human islets following ex-vivo incubation with sustained high glucose and in an in vivo model of chronic mild hyperglycemia. Furthermore, translational downregulation decreased cellular abundance of these proteins. Our findings uncover a translational regulatory circuit during ß-cell glucose toxicity that impairs expression of proteins with critical roles in ß-cell function.
ABSTRACT
OBJECTIVE: Insulin acts on the liver via changes in gene expression to maintain glucose and lipid homeostasis. This study aimed to the Forkhead box protein K1 (FOXK1) associated gene regulatory network as a transcriptional regulator of hepatic insulin action and to determine its role versus FoxO1 and possible actions of the insulin receptor at the DNA level. METHODS: Genome-wide analysis of FoxK1 binding were studied by chromatin immunoprecipitation sequencing and compared to those for IR and FoxO1. These were validated by knockdown experiments and gene expression analysis. RESULTS: Chromatin immunoprecipitation (ChIP) sequencing shows that FoxK1 binds to the proximal promoters and enhancers of over 4000 genes, and insulin enhances this interaction for about 75% of them. These include genes involved in cell cycle, senescence, steroid biosynthesis, autophagy, and metabolic regulation, including glucose metabolism and mitochondrial function and are enriched in a TGTTTAC consensus motif. Some of these genes are also bound by FoxO1. Comparing this FoxK1 ChIP-seq data to that of the insulin receptor (IR) reveals that FoxK1 may act as the transcription factor partner for some of the previously reported roles of IR in gene regulation, including for LARS1 and TIMM22, which are involved in rRNA processing and cell cycle. CONCLUSION: These data demonstrate that FoxK1 is an important regulator of gene expression in response to insulin in liver and may act in concert with FoxO1 and IR in regulation of genes in metabolism and other important biological pathways.
Subject(s)
Gene Regulatory Networks , Receptor, Insulin , Receptor, Insulin/genetics , Receptor, Insulin/metabolism , Gene Expression Regulation , Liver/metabolism , Insulin/metabolismSubject(s)
Hypoglycemia , Insulin Antagonists , Insulin , Insulinoma , Pancreatic Neoplasms , Humans , Antibodies/immunology , Hypoglycemia/etiology , Hypoglycemia/therapy , Insulinoma/complications , Insulinoma/immunology , Insulinoma/therapy , Pancreatic Neoplasms/complications , Pancreatic Neoplasms/immunology , Pancreatic Neoplasms/therapy , Insulin/immunology , Insulin Antagonists/immunology , Insulin Antagonists/therapeutic useABSTRACT
Activating brown adipose tissue (BAT) improves systemic metabolism, making it a promising target for metabolic syndrome. BAT is activated by 12, 13-dihydroxy-9Z-octadecenoic acid (12, 13-diHOME), which we previously identified to be inversely associated with BMI and which directly improves metabolism in multiple tissues. Here we profile plasma lipidomics from a cohort of 83 people and test which lipids' association with BMI replicates in a concordant direction using our novel tool ScreenDMT, whose power and validity we demonstrate via mathematical proofs and simulations. We find that the linoleic acid diols 12, 13-diHOME and 9, 10-diHOME both replicably inversely associate with BMI and mechanistically activate calcium fluxes in mouse brown and white adipocytes in vitro, which implicates this pathway and 9, 10-diHOME as candidate therapeutic targets. ScreenDMT can be applied to test directional mediation, directional replication, and qualitative interactions, such as identifying biomarkers whose association is shared (replication) or opposite (qualitative interaction) across diverse populations.
ABSTRACT
Non-alcoholic fatty liver disease (NAFLD) is a liver manifestation of metabolic syndrome, and is estimated to affect one billion individuals worldwide. An increased intake of a high-fat diet (HFD) and sugar-sweetened beverages are risk-factors for NAFLD development, but how their combined intake promotes progression to a more severe form of liver injury is unknown. Here we show that fructose metabolism via ketohexokinase (KHK) C isoform leads to unresolved endoplasmic reticulum (ER) stress when coupled with a HFD intake. Conversely, a liver-specific knockdown of KHK in mice consuming fructose on a HFD is adequate to improve the NAFLD activity score and exert a profound effect on the hepatic transcriptome. Overexpression of KHK-C in cultured hepatocytes is sufficient to induce ER stress in fructose free media. Upregulation of KHK-C is also observed in mice with genetically induced obesity or metabolic dysfunction, whereas KHK knockdown in these mice improves metabolic function. Additionally, in over 100 inbred strains of male or female mice hepatic KHK expression correlates positively with adiposity, insulin resistance, and liver triglycerides. Similarly, in 241 human subjects and their controls, hepatic Khk expression is upregulated in early, but not late stages of NAFLD. In summary, we describe a novel role of KHK-C in triggering ER stress, which offers a mechanistic understanding of how the combined intake of fructose and a HFD propagates the development of metabolic complications.
Subject(s)
Non-alcoholic Fatty Liver Disease , Animals , Female , Humans , Male , Mice , Diet, High-Fat/adverse effects , Fructokinases/genetics , Fructokinases/metabolism , Fructose/pharmacology , Lipogenesis/physiology , Liver/metabolism , Models, Genetic , Non-alcoholic Fatty Liver Disease/genetics , Non-alcoholic Fatty Liver Disease/metabolism , Obesity/metabolismABSTRACT
AIM: To determine whether continuous glucose monitoring (CGM) can reduce hypoglycaemia in patients with post-bariatric hypoglycaemia (PBH). MATERIALS AND METHODS: In an open-label, nonrandomized, pre-post design with sequential assignment, CGM data were collected in 22 individuals with PBH in two sequential phases: (i) masked (no access to sensor glucose or alarms); and (ii) unmasked (access to sensor glucose and alarms for low or rapidly declining sensor glucose). Twelve participants wore the Dexcom G4 device for a total of 28 days, while 10 wore the Dexcom G6 device for a total of 20 days. RESULTS: Participants with PBH spent a lower percentage of time in hypoglycaemia over 24 hours with unmasked versus masked CGM (<3.3 mM/L, or <60 mg/dL: median [median absolute deviation {MAD}] 0.7 [0.8]% vs. 1.4 [1.7]%, P = 0.03; <3.9 mM/L, or <70 mg/dL: median [MAD] 2.9 [2.5]% vs. 4.7 [4.8]%; P = 0.04), with similar trends overnight. Sensor glucose data from the unmasked phase showed a greater percentage of time spent between 3.9 and 10 mM/L (70-180 mg/dL) (median [MAD] 94.8 [3.9]% vs. 90.8 [5.2]%; P = 0.004) and lower glycaemic variability over 24 hours (median [MAD] mean amplitude of glycaemic excursion 4.1 [0.98] vs. 4.4 [0.99] mM/L; P = 0.04). During the day, participants also spent a greater percentage of time in normoglycaemia with unmasked CGM (median [MAD] 94.2 [4.8]% vs. 90.9 [6.2]%; P = 0.005), largely due to a reduction in hyperglycaemia (>10 mM/L, or 180 mg/dL: median [MAD] 1.9 [2.2]% vs. 3.9 [3.6]%; P = 0.02). CONCLUSIONS: Real-time CGM data and alarms are associated with reductions in low sensor glucose, elevated sensor glucose, and glycaemic variability. This suggests CGM allows patients to detect hyperglycaemic peaks and imminent hypoglycaemia, allowing dietary modification and self-treatment to reduce hypoglycaemia. The use of CGM devices may improve safety in PBH, particularly for patients with hypoglycaemia unawareness.
Subject(s)
Bariatrics , Diabetes Mellitus, Type 1 , Hypoglycemia , Humans , Blood Glucose , Blood Glucose Self-Monitoring , Hypoglycemia/diagnosis , Hypoglycemia/etiology , Hypoglycemia/prevention & controlABSTRACT
Non-alcoholic fatty liver disease (NAFLD) is a liver manifestation of metabolic syndrome, and is estimated to affect one billion individuals worldwide. An increased intake of a high-fat diet (HFD) and sugar-sweetened beverages are risk-factors for NAFLD development, but how their combined intake promotes progression to a more severe form of liver injury is unknown. Here we show that fructose metabolism via ketohexokinase (KHK) C isoform increases endoplasmic reticulum (ER) stress in a dose dependent fashion, so when fructose is coupled with a HFD intake it leads to unresolved ER stress. Conversely, a liver-specific knockdown of KHK in C57BL/6J male mice consuming fructose on a HFD is adequate to improve the NAFLD activity score and exert a profound effect on the hepatic transcriptome. Overexpression of KHK-C in cultured hepatocytes is sufficient to induce ER stress in fructose free media. Upregulation of KHK-C is also observed in genetically obesity ob/ob, db/db and lipodystrophic FIRKO male mice, whereas KHK knockdown in these mice improves metabolic function. Additionally, in over 100 inbred strains of male or female mice hepatic KHK expression correlates positively with adiposity, insulin resistance, and liver triglycerides. Similarly, in 241 human subjects and their controls, hepatic Khk expression is upregulated in early, but not late stages of NAFLD. In summary, we describe a novel role of KHK-C in triggering ER stress, which offers a mechanistic understanding of how the combined intake of fructose and a HFD propagates the development of metabolic complications.
ABSTRACT
Insulin acts through the insulin receptor (IR) tyrosine kinase to exert its classical metabolic and mitogenic actions. Here, using receptors with either short or long deletion of the ß-subunit or mutation of the kinase active site (K1030R), we have uncovered a second, previously unrecognized IR signaling pathway that is intracellular domain-dependent, but ligand and tyrosine kinase-independent (LYK-I). These LYK-I actions of the IR are linked to changes in phosphorylation of a network of proteins involved in the regulation of extracellular matrix organization, cell cycle, ATM signaling and cellular senescence; and result in upregulation of expression of multiple extracellular matrix-related genes and proteins, down-regulation of immune/interferon-related genes and proteins, and increased sensitivity to apoptosis. Thus, in addition to classical ligand and tyrosine kinase-dependent (LYK-D) signaling, the IR regulates a second, ligand and tyrosine kinase-independent (LYK-I) pathway, which regulates the cellular machinery involved in senescence, matrix interaction and response to extrinsic challenges.
Subject(s)
Apoptosis , Cell Division , Cellular Senescence , Protein-Tyrosine Kinases , Receptor, Insulin , Apoptosis/genetics , Cell Division/genetics , Insulin/metabolism , Ligands , Phosphorylation , Protein-Tyrosine Kinases/metabolism , Receptor, Insulin/genetics , Receptor, Insulin/metabolism , Cellular Senescence/genetics , Humans , Animals , MiceABSTRACT
Insulin and IGF-1 receptors (IR and IGF1R) are highly homologous and share similar signaling systems, but each has a unique physiological role, with IR primarily regulating metabolic homeostasis and IGF1R regulating mitogenic control and growth. Here, we show that replacement of a single amino acid at position 973, just distal to the NPEY motif in the intracellular juxtamembrane region, from leucine, which is highly conserved in IRs, to phenylalanine, the highly conserved homologous residue in IGF1Rs, resulted in decreased IRS-1/PI3K/Akt/mTORC1 signaling and increased Shc/Gab1/MAPK cell cycle signaling. As a result, cells expressing L973F-IR exhibited decreased insulin-induced glucose uptake, increased cell growth, and impaired receptor internalization. Mice with knockin of the L973F-IR showed similar alterations in signaling in vivo, and this led to decreased insulin sensitivity, a modest increase in growth, and decreased weight gain when mice were challenged with a high-fat diet. Thus, leucine-973 in the juxtamembrane region of the IR acts as a crucial residue differentiating IR signaling from IGF1R signaling.
Subject(s)
Insulin , Receptor, IGF Type 1 , Receptor, Insulin , Signal Transduction , Animals , Mice , Insulin/metabolism , Insulin Receptor Substrate Proteins/genetics , Insulin Receptor Substrate Proteins/metabolism , Insulin-Like Growth Factor I/metabolism , Insulin-Like Growth Factor I/pharmacology , Leucine/genetics , Phosphatidylinositol 3-Kinases/metabolism , Phosphoproteins/metabolism , Phosphorylation , Receptor, IGF Type 1/genetics , Receptor, IGF Type 1/metabolism , Receptor, Insulin/genetics , Receptor, Insulin/metabolism , Signal Transduction/genetics , HumansABSTRACT
Prevention or amelioration of declining ß cell mass is a potential strategy to cure diabetes. Here, we report the pathways utilized by ß cells to robustly replicate in response to acute insulin resistance induced by S961, a pharmacological insulin receptor antagonist. Interestingly, pathways that include CENP-A and the transcription factor E2F1 that are independent of insulin signaling and its substrates appeared to mediate S961-induced ß cell multiplication. Consistently, pharmacological inhibition of E2F1 blocks ß-cell proliferation in S961-injected mice. Serum from S961-treated mice recapitulates replication of ß cells in mouse and human islets in an E2F1-dependent manner. Co-culture of islets with adipocytes isolated from S961-treated mice enables ß cells to duplicate, while E2F1 inhibition limits their growth even in the presence of adipocytes. These data suggest insulin resistance-induced proliferative signals from adipocytes activate E2F1, a potential therapeutic target, to promote ß cell compensation.
Subject(s)
Insulin Resistance , Insulin-Secreting Cells , Animals , Cell Proliferation , Centromere Protein A/metabolism , E2F1 Transcription Factor/metabolism , Humans , Insulin/metabolism , Insulin-Secreting Cells/metabolism , Mice , Mice, Knockout , Receptor, Insulin/metabolismABSTRACT
To improve the power of mediation in high-throughput studies, here we introduce High-throughput mediation analysis (Hitman), which accounts for direction of mediation and applies empirical Bayesian linear modeling. We apply Hitman in a retrospective, exploratory analysis of the SLIMM-T2D clinical trial in which participants with type 2 diabetes were randomized to Roux-en-Y gastric bypass (RYGB) or nonsurgical diabetes/weight management, and fasting plasma proteome and metabolome were assayed up to 3 years. RYGB caused greater improvement in HbA1c, which was mediated by growth hormone receptor (GHR). GHR's mediation is more significant than clinical mediators, including BMI. GHR decreases at 3 months postoperatively alongside increased insulin-like growth factor binding proteins IGFBP1/BP2; plasma GH increased at 1 year. Experimental validation indicates (1) hepatic GHR expression decreases in post-bariatric rats; (2) GHR knockdown in primary hepatocytes decreases gluconeogenic gene expression and glucose production. Thus, RYGB may induce resistance to diabetogenic effects of GH signaling.Trial Registration: Clinicaltrials.gov NCT01073020.
Subject(s)
Diabetes Mellitus, Type 2/blood , Gastric Bypass , Liver/metabolism , Metabolome , Obesity/blood , Proteome , Animals , Biomarkers/blood , Blood Glucose/metabolism , Body Mass Index , Carrier Proteins/blood , Carrier Proteins/genetics , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/pathology , Diabetes Mellitus, Type 2/surgery , Dipeptidases/blood , Dipeptidases/genetics , Fasting/physiology , Gene Expression Regulation , Glycated Hemoglobin/genetics , Glycated Hemoglobin/metabolism , Hepatocytes/metabolism , Hepatocytes/pathology , Human Growth Hormone/blood , Human Growth Hormone/genetics , Humans , Insulin-Like Growth Factor Binding Protein 1/blood , Insulin-Like Growth Factor Binding Protein 1/genetics , Insulin-Like Growth Factor Binding Protein 2/blood , Insulin-Like Growth Factor Binding Protein 2/genetics , Liver/pathology , Obesity/genetics , Obesity/pathology , Obesity/surgery , Primary Cell Culture , Rats , Retrospective StudiesABSTRACT
Insulin resistance is present in one-quarter of the general population, predisposing these people to a wide range of diseases. Our aim was to identify cell-intrinsic determinants of insulin resistance in this population using induced pluripotent stem cell-derived (iPSC-derived) myoblasts (iMyos). We found that these cells exhibited a large network of altered protein phosphorylation in vitro. Integrating these data with data from type 2 diabetic iMyos revealed critical sites of conserved altered phosphorylation in IRS-1, AKT, mTOR, and TBC1D1 in addition to changes in protein phosphorylation involved in Rho/Rac signaling, chromatin organization, and RNA processing. There were also striking differences in the phosphoproteome in cells from men versus women. These sex-specific and insulin-resistance defects were linked to functional differences in downstream actions. Thus, there are cell-autonomous signaling alterations associated with insulin resistance within the general population and important differences between men and women, many of which also occur in diabetes, that contribute to differences in physiology and disease.
Subject(s)
Diabetes Mellitus, Type 2/metabolism , Insulin Resistance , Sex Characteristics , Signal Transduction , Female , GTPase-Activating Proteins/metabolism , Humans , Insulin Receptor Substrate Proteins/metabolism , Male , Proto-Oncogene Proteins c-akt/metabolism , TOR Serine-Threonine Kinases/metabolismABSTRACT
BACKGROUND: Human pancreatic islets are a central focus of research in metabolic studies. Transcriptomics is frequently used to interrogate alterations in cultured human islet cells using single-cell RNA-sequencing (scRNA-seq). We introduce single-nucleus RNA-sequencing (snRNA-seq) as an alternative approach for investigating transplanted human islets. METHODS: The Nuclei EZ protocol was used to obtain nuclear preparations from fresh and frozen human islet cells. Such preparations were first used to generate snRNA-seq datasets and compared to scRNA-seq output obtained from cells from the same donor. Finally, we employed snRNA-seq to obtain the transcriptomic profile of archived human islets engrafted in immunodeficient animals. RESULTS: We observed virtually complete concordance in identifying cell types and gene proportions as well as a strong association of global and islet cell type gene signatures between scRNA-seq and snRNA-seq applied to fresh and frozen cultured or transplanted human islet samples. CONCLUSIONS: We propose snRNA-seq as a reliable strategy to probe transcriptomic profiles of freshly harvested or frozen sources of transplanted human islet cells especially when scRNA-seq is not ideal.
Subject(s)
Gene Expression Profiling , Gene Expression Regulation , Islets of Langerhans/metabolism , Single-Cell Analysis , Transcriptome , Animals , Biomarkers , Humans , Islets of Langerhans/cytology , Islets of Langerhans Transplantation , Mice , Sequence Analysis, DNA , Single-Cell Analysis/methods , Exome SequencingABSTRACT
CONTEXT: Severe hypoglycemia with neuroglycopenia, termed post-bariatric hypoglycemia (PBH). typically occurs postprandially, but it is also reported after activity or mid-nocturnally. OBJECTIVE: To quantify glycemia, glycemic variability, and magnitude/duration of low sensor glucose (SG) values in patients with PBH after Roux-en-Y gastric bypass (PBH-RYGB). METHODS: This retrospective analysis of data from an academic medical center included individuals with PBH-RYGB (nâ =â 40), reactive hypoglycemia without gastrointestinal surgery (Non-Surg Hypo, nâ =â 20), prediabetes (Pre-DM, nâ =â 14), newly diagnosed T2D (nâ =â 5), and healthy controls (HC, nâ =â 38). Masked continuous glucose monitoring (Dexcom G4) was used to assess patterns over 24 hours, daytime (6 am-midnight) and nighttime (midnight-6 am). Prespecified measures included mean and median SG, variability, and percent time at thresholds of sensor glucose. RESULTS: Mean and median SG were similar for PBH-RYGB and HC (mean: 99.8â ±â 18.6 vs 96.9â ±â 10.2 mg/dL; median: 93.0â ±â 14.8 vs 94.5â ±â 7.4 mg/dL). PBH-RYGB had a higher coefficient of variation (27.3â ±â 6.8 vs 17.9â ±â 2.4%, Pâ <â 0.0001) and range (154.5â ±â 50.4 vs 112.0â ±â 26.7 mg/dL, Pâ <â 0.0001). Nadir was lowest in PBH-RYGB (42.5â ±â 3.7 vs HC 49.0â ±â 11.9 mg/dL, Pâ =â 0.0046), with >2-fold greater time with SGâ <â 70 mg/dL vs HC (7.7â ±â 8.4 vs 3.2â ±â 4.1%, Pâ =â 0.0013); these differences were greater at night (12.6â ±â 16.9 vs 1.0â ±â 1.5%, Pâ <â 0.0001). Non-Surg Hypo also had 4-fold greater time with SGâ <â 70 at night vs HC (SGâ <â 70: 4.0â ±â 5.9% vs 1.0â ±â 1.5%), but glycemic variability was not increased. CONCLUSION: Patients with PBH-RYGB experience higher glycemic variability and frequency of SGâ <â 70 compared to HC, especially at night. These data suggest that additional pathophysiologic mechanisms beyond prandial changes contribute to PBH.
Subject(s)
Blood Glucose/metabolism , Gastric Bypass/adverse effects , Hypoglycemia/blood , Postoperative Complications/blood , Adult , Blood Glucose Self-Monitoring , Female , Humans , Hypoglycemia/etiology , Male , Middle Aged , Postprandial Period/physiology , Retrospective StudiesABSTRACT
Insulin and insulin-like growth factor 1 (IGF-1) receptors share many downstream signaling pathways but have unique biological effects. To define the molecular signals contributing to these distinct activities, we performed global phosphoproteomics on cells expressing either insulin receptor (IR), IGF-1 receptor (IGF1R), or chimeric IR-IGF1R receptors. We show that IR preferentially stimulates phosphorylations associated with mammalian target of rapamycin complex 1 (mTORC1) and Akt pathways, whereas IGF1R preferentially stimulates phosphorylations on proteins associated with the Ras homolog family of guanosine triphosphate hydrolases (Rho GTPases), and cell cycle progression. There were also major differences in the phosphoproteome between cells expressing IR versus IGF1R in the unstimulated state, including phosphorylation of proteins involved in membrane trafficking, chromatin remodeling, and cell cycle. In cells expressing chimeric IR-IGF1R receptors, these differences in signaling could be mapped to contributions of both the extra- and intracellular domains of these receptors. Thus, despite their high homology, IR and IGF1R preferentially regulate distinct networks of phosphorylation in both the basal and stimulated states, allowing for the unique effects of these hormones on organismal function.
Subject(s)
Antigens, CD/metabolism , Receptor, IGF Type 1/metabolism , Receptor, Insulin/metabolism , Adipocytes/metabolism , Animals , Cell Division/drug effects , Cell Line , Female , Humans , Insulin/metabolism , Insulin-Like Growth Factor I/metabolism , Male , Mechanistic Target of Rapamycin Complex 1/physiology , Mice , Phosphatidylinositol Phosphates/metabolism , Phosphorylation/drug effects , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction/genetics , Signal Transduction/physiology , rho GTP-Binding Proteins/metabolismABSTRACT
The recently elucidated proresolving conjugates in tissue regeneration (CTR) maresin-CTR (MCTR), protectin-CTR (PCTR), and resolvin-CTR (RCTR), termed cysteinyl-specialized proresolving mediators (cys-SPMs) each promotes regeneration, controls infection, and accelerates resolution of inflammation. Here, we sought evidence for cys-SPM activation of primordial pathways in planaria (Dugesia japonica) regeneration that might link resolution of inflammation and regeneration. On surgical resection, planaria regeneration was enhanced with MCTR3, PCTR3, or RCTR3 (10 nM), each used for RNA sequencing. The three cys-SPMs shared up-regulation of 175 known transcripts with fold-change > 1.25 and combined false discovery rate (FDR) < 0.002, and 199 canonical pathways (FDR < 0.25), including NF-κB pathways and an ortholog of human TRAF3 (TNFR-associated factor 3). Three separate pathway analyses converged on TRAF3 up-regulation by cys-SPMs. With human macrophages, three cys-SPMs each dose-dependently increased TRAF3 expression in a cAMP-PKA-dependent manner. TRAF3 overexpression in macrophages enhanced Interleukin-10 (IL-10) and phagocytosis of Escherichia coli IL-10 also increased phagocytosis in a dose-dependent manner. Silencing of mouse TRAF3 in vivo significantly reduced IL-10 and macrophage phagocytosis. TRAF3 silencing in vivo also relieved cys-SPMs' actions in limiting polymorphonuclear neutrophil in E. coli exudates. These results identify cys-SPM-regulated pathways in planaria regeneration, uncovering a role for TRAF3/IL-10 in regulating mammalian phagocyte functions in resolution. Cys-SPM activation of TRAF3 signaling is a molecular component of both regeneration and resolution of infectious inflammation.