Regulation of systemic metabolism by the autonomic nervous system consisting of afferent and efferent innervation.

Autonomic nerves, sympathetic and parasympathetic, innervate organs and modulate their functions. It has become evident that afferent and efferent signals of the autonomic nervous system play important roles in regulating systemic metabolism, thereby maintaining homeostasis at the whole-body level. Vagal afferent nerves receive signals, such as nutrients and hormones, from the peripheral organs/tissues including the gastrointestinal tract and adipose tissue then transmit these signals to the hypothalamus, thereby regulating feeding behavior. In addition to roles in controlling appetite, areas in the hypothalamus serve as regulatory centers of both sympathetic and parasympathetic efferent fibers. These efferent innervations regulate the functions of peripheral organs/tissues, such as pancreatic islets, adipose tissues and the liver, which play roles in metabolic regulation. Furthermore, recent evidence has unraveled the metabolic regulatory systems governed by autonomic nerve circuits. In these systems, afferent nerves transmit metabolic information from peripheral organs to the central nervous system (CNS) and the CNS thereby regulates the organ functions through the efferent fibers of autonomic nerves. Thus, the autonomic nervous system regulates the homeostasis of systemic metabolism, and both afferent and efferent fibers play critical roles in its regulation. In addition, several lines of evidence demonstrate the roles of the autonomic nervous system in regulating and dysregulating the immune system. This review introduces variety of neuron-mediated inter-organ cross-talk systems and organizes the current knowledge of autonomic control/coordination of systemic metabolism, focusing especially on a liver-brain-pancreatic ß-cell autonomic nerve circuit, as well as highlighting the potential importance of connections with the neuronal and immune systems.

Type 1 Diabetes Mellitus Associated with Nivolumab after Second SARS-CoV-2 Vaccination, Japan.

Recently, along with increasing use of immune checkpoint inhibitors such as nivolumab, the incidence of immune-related adverse events, including type 1 diabetes mellitus, has become a serious problem. We report a patient who had immune checkpoint inhibitor‒associated type 1 diabetes mellitus that developed after a second mRNA-based SARS-CoV-2 vaccination.

The return of individual genomic results to research participants: design and pilot study of Tohoku Medical Megabank Project.

Certain large genome cohort studies attempt to return the individual genomic results to the participants; however, the implementation process and psychosocial impacts remain largely unknown. The Tohoku Medical Megabank Project has conducted large genome cohort studies of general residents. To implement the disclosure of individual genomic results, we extracted the potential challenges and obstacles. Major challenges include the determination of genes/disorders based on the current medical system in Japan, the storage of results, prevention of misunderstanding, and collaboration of medical professionals. To overcome these challenges, we plan to conduct multilayer pilot studies, which deal with different disorders/genes. We finally chose familial hypercholesterolemia (FH) as a target disease for the first pilot study. Of the 665 eligible candidates, 33.5% were interested in the pilot study and provided consent after an educational "genetics workshop" on the basic genetics and medical facts of FH. The genetics professionals disclosed the results to the participants. All positive participants were referred to medical care, and a serial questionnaire revealed no significant psychosocial distress after the disclosure. Return of genomic results to research participants was implemented using a well-prepared protocol. To further elucidate the impact of different disorders, we will perform multilayer pilot studies with different disorders, including actionable pharmacogenomics and hereditary tumor syndromes.

New classification and diagnostic criteria for insulin resistance syndrome.

This report of a working group established by the Japan Diabetes Society proposes a new classification and diagnostic criteria for insulin resistance syndrome. Insulin resistance syndrome is defined as a condition characterized by severe attenuation of insulin action due to functional impairment of the insulin receptor or its downstream signaling molecules. This syndrome is classified into two types: genetic insulin resistance syndrome, caused by gene abnormalities, and type B insulin resistance syndrome, caused by autoantibodies to the insulin receptor. Genetic insulin resistance syndrome includes type A insulin resistance as well as Donohue and Rabson-Mendenhall syndromes, all of which are caused by abnormalities of the insulin receptor gene; conditions such as SHORT syndrome caused by abnormalities of PIK3R1, which encodes a regulatory subunit of phosphatidylinositol 3-kinase; conditions caused by abnormalities of AKT2, TBC1D4, or PRKCE; and conditions in which a causative gene has not yet been identified. Type B insulin resistance syndrome is characterized by severe impairment of insulin action due to the presence of insulin receptor autoantibodies. Cases in which hypoglycemia alone is induced by autoantibodies that stimulate insulin receptor were not included in Type B insulin resistance syndrome.

Extraordinarily long-inactive solitary fibrous tumor transformed to produce big insulin-like growth factor-2, leading to hypoglycemia and rapid liposarcoma growth: a case report.

BACKGROUND: A high-molecular-weight form of insulin-like growth factor-2 (IGF-2), known as "big" IGF-2, is occasionally produced by various tumor types, leading to hypoglycemia. Although solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm, it has been estimated that 4-6% of SFT patients develop hypoglycemia due to circulating big IGF-2. The mean time elapsed from tumor detection until the onset of hypoglycemia is reportedly less than one year (8.5 ± 1.9 months). CASE PRESENTATION: A 68-year-old man was hospitalized for exacerbation of recurring hypoglycemic episodes. He had been diagnosed with an SFT 17 years before the onset of hypoglycemia, and the SFT had already been very large at that time. The tumor, which was non-resectable and refractory to chemotherapies, had slowly increased in size since the initial diagnosis. Half a year before the hypoglycemic episodes manifested, another tumor, adjacent to the left kidney, was newly identified. Fluorodeoxyglucose positron emission tomography-computed tomography scanning, revealed the left peri-renal tumor to show much higher fluorodeoxyglucose uptake than the preexisting SFT, suggesting that it was unlikely to be a metastasis from the SFT. Abundant serum big IGF-2 was detected by western immunoblot analysis, indicating it to be the cause of the hypoglycemia. Since the 17 years between SFT detection and the onset of IGF-2-induced hypoglycemia was an extremely long period as compared with those in previous reports, we initially suspected that the new, peri-renal tumor had produced big IGF-2, but transcatheter arterial embolization of its feeding arteries did not suppress hypoglycemia. Notably, by measuring the tumor volume doubling time, the peri-renal tumor growth was shown to be markedly accelerated in parallel with exacerbation of the hypoglycemia. The patient died of heart failure 21 months after the onset of hypoglycemia. Unexpectedly, autopsy revealed that big IGF-2 had been produced only by the preexisting SFT, not the peri-renal tumor, and that the peri-renal tumor was a dedifferentiated liposarcoma. CONCLUSIONS: We should keep in mind that even a long-inactive SFT can undergo transformation to produce big IGF-2, which then acts on both insulin and IGF-1 receptors, possibly leading to both hypoglycemia and the development/growth of another tumor, respectively.

Branched chain amino acids are associated with the heterogeneity of the area of lipid droplets in hepatocytes of patients with non-alcoholic fatty liver disease.

AIM: Macrovesicular steatosis around the central vein (zone 3) is one of the pathological features of non-alcoholic fatty liver disease or steatohepatitis (NAFLD/NASH). The aim of this study is to elucidate precisely the association between the area of lipid droplets (LDs) and the plasma metabolic parameters in patients with NAFLD/NASH. METHODS: Eighty patients with NAFLD/NASH diagnosed by needle biopsy were enrolled. The LDs around zone 3 were counted automatically by image processing software, the total area of LDs (TLDs), the maximum area of LDs (MAXLDs), the average area of LDs (AVELDs) and the heterogeneity by the coefficient of variation (CV [%]) were quantified. The correlations between these values and plasma metabolic parameters were analyzed. We evaluated the association between branched chain amino acids (BCAAs) and the heterogeneity of LDs in hepatocytes in vitro and in vivo. RESULTS: The MAXLDs was significantly correlated with more metabolic parameters than AVELDs and TLDs. The level of BCAAs was independently associated with the CV among the metabolic parameters. In early stage NAFLD, aspartate and alanine aminotransferase were significantly higher in the high CV group than in the low CV group. The high concentration of BCAAs increased the CV of LDs in hepatocytes accompanied by the expression of phosphor-p70 S6 kinase and sterol regulatory element-binding protein 1 in vitro. A high BCAA diet induced high heterogeneity of LDs around zone 3 in ob/ob mice. CONCLUSIONS: The levels of BCAAs were associated with the LD heterogeneity of hepatocytes around zone 3 in patients with NAFLD/NASH.

Enhancement of postprandial endogenous insulin secretion rather than exogenous insulin injection ameliorated insulin antibody-induced unstable diabetes: a case report.

BACKGROUND: Insulin injection, especially with insulin analogs, occasionally induces the production of insulin antibodies with high binding capacity and low affinity, similar to the insulin autoantibodies characteristic of insulin autoimmune syndrome (IAS). Production of these "IAS-like" insulin antibodies causes marked glycemic fluctuations with postprandial hyperglycemia and fasting hypoglycemia. CASE PRESENTATION: A 66-year-old man with a 27-year history of diabetes was admitted because of marked glycemic fluctuations. Human insulin treatment had been initiated at age 56, followed by multiple daily injections of insulin analogs 5 years later. After the initial year of insulin analog treatment, the patient began to experience frequent morning hypoglycemic attacks and day-time hyperglycemia. Marked hyperinsulinemia (4500 µU/mL) and high titers of insulin antibodies (80.4%) with high binding capacity and low affinity indicated that IAS-like insulin antibodies were causing severe glucose fluctuations. Altering insulin formulations (insulin aspart → regular human insulin→ insulin lispro) proved to be ineffective. After several therapeutic trials, cessation of exogenous insulin and addition of mitiglinide to liraglutide with voglibose finally attenuated glycemic fluctuations with increased postprandial insulin secretion. Continuous glucose monitoring revealed improvement of morning hypoglycemia and postprandial hyperglycemia with smaller mean amplitude of glycemic excursion. Therefore, compared to exogenously injected insulin, endogenously secreted insulin directly and rapidly acts on hepatocytes and suppresses postprandial glucose output. CONCLUSIONS: Proper enhancement of postprandial endogenous insulin aimed at suppressing postprandial glucose output without stimulating excessive glucose uptake in the periphery is potentially useful for treating diabetes with insulin antibody-induced glycemic instability.

Eruptive xanthomas in a patient with soft-drink diabetic ketosis and apolipoprotein E4/2.

Soft-drink diabetic ketosis, characterized by acute onset ketosis induced by excessive ingestion of sugar-containing drinks, is often seen in obese, young patients, even with undiagnosed type 2 diabetes. We herein report a 15-year-old obese patient with the apolipoprotein E4/2 phenotype, in whom eruptive xanthomas lead to a diagnosis of soft-drink diabetic ketosis. He developed multiple asymptomatic yellowish papules on the auricles, back, buttocks and the extensor surfaces of the elbows and knees. He initially visited a dermatology clinic and his blood triglyceride and HbA1c levels were found to be 6,490 mg/dL and 16.5%, respectively. He was referred to our hospital for treatment of hyperglycemia and hypertyriglyceridemia. On admission, he had ketonuria and increased blood levels of 3-hydroxybutylate and acetoacetate. He habitually drank 1-3 litters of sweet beverages daily to quench his thirst. Therefore, "soft-drink diabetic ketosis" was diagnosed. Severe hypertriglyceridemia was considered to have been a consequence of impaired insulin action and his apolipoprotein E4/2 phenotype. We treated the diabetic ketosis and hypertriglyceridemia with intensive insulin therapy and a fat-restricted diet. At discharge, he no longer required insulin therapy and his blood glucose levels were controlled with metformin and voglibose. Along with amelioration of the hyperglycemia, triglyceride levels decreased to 247 mg/dL without administration of anti-hyperlipidemia agents. The eruptive xanthoma lesions gradually diminished in size and number and eventually disappeared by 12 months. This case provides an instructive example of eruptive xanthomas serving as a sign of severe dysregulation, not only of lipid, but also glucose, metabolism.

Laparoscopic Sleeve Gastrectomy on Severe Obesity after Intracranial Germinoma Treatment: A Case Report.

Hypothalamic obesity is a clinical syndrome characterized by severe and refractory obesity that is caused by hypothalamic function impairment. Recently, bariatric surgery has been attempted for patients with hypothalamic obesity after craniopharyngioma, but experiences have not yet been accumulated in other hypothalamic disorders. Here, we report the case of a 39-year-old male patient with panhypopituitarism who received laparoscopic sleeve gastrectomy (LSG) after intracranial germinoma treatment. The patient was diagnosed with intracranial germinoma at age 15 and achieved complete remission after radiotherapy (total 50 Gy). He was obese during diagnosis [body mass index (BMI), 29.2 kg/m2], and his obesity gradually worsened after the intracranial germinoma treatment, and LSG was considered when his BMI was 48.6 kg/m2. After 1 month of hospitalized diet-exercise program, LSG was performed. After LSG, his BMI gradually decreased and reached 38.8 kg/m2 on the day of discharge (6 weeks after the surgery). Five months after LSG, his insulin resistance improved, but insulin hypersecretion remained. Fifteen months after the surgery, his BMI was 31.2 kg/m2, with marked decrease in visceral and subcutaneous fat areas (from 393.8 cm2 and 168.2 cm2 before the surgery to 111.5 cm2 and 56.3 cm2, respectively.). To our knowledge, this is the first case of LSG for hypothalamic obesity after intracranial germinoma treatment. Although the pathophysiology of hypothalamic obesity is different from that of primary obesity, LSG could be a successful therapeutic choice for patients with hypothalamic obesity after the intracranial germinoma treatment.

Deficient ganglioside synthesis restores responsiveness to leptin and melanocortin signaling in obese KKAy mice.

GM3, a precursor for synthesis of a- and b-series gangliosides, is elevated in adipocytes of obese model animals and in sera of obese human patients with type 2 diabetes and/or dyslipidemia. GM3 synthase (GM3S)-KO C57BL/6 mice display enhanced insulin sensitivity and reduced development of high-fat diet-induced insulin resistance. However, the pathophysiological roles of GM3 and related gangliosides in the central control of feeding and metabolism remain unclear. We found that a mouse model (KKAy GM3S KO) generated by KO of the GM3S gene in the yellow obese strain, KKAy, displayed significant amelioration of obese phenotype. Whereas KKAy mice were hyperphagic and developed severe obesity, KKAy GM3S KO mice had significantly lower body weight and food intake, and greater glucose and insulin tolerance. The hypothalamic response to intraperitoneal administration of leptin was greatly reduced in KKAy mice, but was retained in KKAy GM3S KO mice. In studies of a cultured mouse hypothalamic neuronal cell line, enhanced leptin-dependent phosphorylation of ERK was observed in GM3S-deficient cells. Furthermore, KKAy GM3S KO mice did show altered coat color, suggesting that GM3S is also involved in melanocortin signaling. Our findings, taken together, indicate that GM3-related gangliosides play key roles in leptin and melanocortin signaling.

Metformin directly binds the alarmin HMGB1 and inhibits its proinflammatory activity.

Metformin is the first-line drug in the treatment of type 2 diabetes. In addition to its hypoglycemic effect, metformin has an anti-inflammatory function, but the precise mechanism promoting this activity remains unclear. High mobility group box 1 (HMGB1) is an alarmin that is released from necrotic cells and induces inflammatory responses by its cytokine-like activity and is, therefore, a target of anti-inflammatory therapies. Here we identified HMGB1 as a novel metformin-binding protein by affinity purification using a biotinylated metformin analogue. Metformin directly bound to the C-terminal acidic tail of HMGB1. Both in vitro and in vivo, metformin inhibited inflammatory responses induced by full-length HMGB1 but not by HMGB1 lacking the acidic tail. In an acetaminophen-induced acute liver injury model in which HMGB1 released from injured cells exacerbates the initial injury, metformin effectively reduced liver injury and had no additional inhibitory effects when the extracellular HMGB1 was blocked by anti-HMGB1-neutralizing antibody. In summary, we report for the first time that metformin suppresses inflammation by inhibiting the extracellular activity of HMGB1. Because HMGB1 plays a major role in inflammation, our results suggest possible new ways to manage HMGB1-induced inflammation.

Activation of the Hypoxia Inducible Factor 1α Subunit Pathway in Steatotic Liver Contributes to Formation of Cholesterol Gallstones.

BACKGROUND & AIMS: Hypoxia-inducible factor 1α subunit (HIF1A) is a transcription factor that controls the cellular response to hypoxia and is activated in hepatocytes of patients with nonalcoholic fatty liver disease (NAFLD). NAFLD increases the risk for cholesterol gallstone disease by unclear mechanisms. We studied the relationship between HIF1A and gallstone formation associated with liver steatosis. METHODS: We performed studies with mice with inducible disruption of Hif1a in hepatocytes via a Cre adenoviral vector (inducible hepatocyte-selective HIF1A knockout [iH-HIFKO] mice), and mice without disruption of Hif1a (control mice). Mice were fed a diet rich in cholesterol and cholate for 1 or 2 weeks; gallbladders were collected and the number of gallstones was determined. Livers and biliary tissues were analyzed by histology, quantitative reverse-transcription polymerase chain reaction, immunohistochemistry, and immunoblots. We measured concentrations of bile acid, cholesterol, and phospholipid in bile and rates of bile flow. Primary hepatocytes and cholangiocytes were isolated and analyzed. HIF1A was knocked down in Hepa1-6 cells with small interfering RNAs. Liver biopsy samples from patients with NAFLD, with or without gallstones, were analyzed by quantitative reverse-transcription polymerase chain reaction. RESULTS: Control mice fed a diet rich in cholesterol and cholate developed liver steatosis with hypoxia; levels of HIF1A protein were increased in hepatocytes around central veins and 90% of mice developed cholesterol gallstones. Only 20% of the iH-HIFKO mice developed cholesterol gallstones. In iH-HIFKO mice, the biliary lipid concentration was reduced by 36%, compared with control mice, and bile flow was increased by 35%. We observed increased water secretion from hepatocytes into bile canaliculi to mediate these effects, resulting in suppression of cholelithogenesis. Hepatic expression of aquaporin 8 (AQP8) protein was 1.5-fold higher in iH-HIFKO mice than in control mice. Under hypoxic conditions, cultured hepatocytes increased expression of Hif1a, Hmox1, and Vegfa messenger RNAs (mRNAs), and down-regulated expression of AQP8 mRNA and protein; AQP8 down-regulation was not observed in cells with knockdown of HIF1A. iH-HIFKO mice had reduced inflammation and mucin deposition in the gallbladder compared with control mice. Liver tissues from patients with NAFLD with gallstones had increased levels of HIF1A, HMOX1, and VEGFA mRNAs, compared with livers from patients with NAFLD without gallstones. CONCLUSIONS: In steatotic livers of mice, hypoxia up-regulates expression of HIF1A, which reduces expression of AQP8 and concentrates biliary lipids via suppression of water secretion from hepatocytes. This promotes cholesterol gallstone formation. Livers from patients with NAFLD and gallstones express higher levels of HIF1A than livers from patients with NAFLD without gallstones.

Selective insulin resistance with differential expressions of IRS-1 and IRS-2 in human NAFLD livers.

BACKGROUND/OBJECTIVE: Insulin signals, via the regulation of key enzyme expression, both suppress gluconeogenesis and enhance lipid synthesis in the liver. Animal studies have revealed insulin signaling favoring gluconeogenesis suppression to be selectively impaired in steatotic livers. However, whether, and if so how, such selective insulin resistance occurs in human steatotic livers remains unknown. Our aim was to investigate selective insulin resistance in human livers with non-alcoholic fatty liver disease (NAFLD). SUBJECTS/METHODS: We examined mRNA expressions of key molecules for insulin signaling, gluconeogenesis and lipogenesis in human liver biopsy samples obtained from 51 non-diabetic subjects: 9 healthy controls and 42 NAFLD patients, and analyzed associations of these molecules with each other and with detailed pathological and clinical biochemistry data. RESULTS: In NAFLD patients, insulin receptor substrate (IRS)-2 expression was decreased, while those of key enzymes for gluconeogenesis were increased. These alterations of IRS-2 and gluconeogenesis enzymes were induced both in simple steatosis (SS) and non-alcoholic steatohepatitis (NASH), while these expression levels did not differ between SS and NASH. Furthermore, alterations in the expressions of IRS-2 and gluconeogenesis enzymes showed strong negative correlations and were concurrently induced in the early histological stage of NAFLD. In contrast, fatty acid synthase (FAS) expression was not decreased in NAFLD, despite IRS-2 downregulation, but correlated strongly with IRS-1 expression. Furthermore, no histological scores were associated with these molecules. Thus, IRS-1 signaling, which is not impaired in NAFLD, appears to modulate FAS expression. CONCLUSION: These analyses revealed that selective insulin resistance is present in human NAFLD livers and occurs in its early phases. The effect of insulin, during the IRS step, on gene expressions for lipogenesis and gluconeogenesis are apparently distinct and preferential downregulation of IRS-2 may contribute to selective resistance to the suppressive effects of insulin on gluconeogenesis.

Genomewide approaches for BACH1 target genes in mouse embryonic fibroblasts showed BACH1-Pparg pathway in adipogenesis.

The transcription repressor BTB and CNC homology 1 (BACH1) represses genes involved in heme metabolism and oxidative stress response. BACH1 also suppresses the p53-dependent cellar senescence in primary mouse embryonic fibroblasts (MEFs). To investigate the role of BACH1 in MEF other than its known functions, we carried out a genomewide mapping of binding site for BACH1 and its heterodimer partner MAFK in immortalized MEFs (iMEFs) using chromatin immunoprecipitation and next-generation sequencing technology (ChIP-sequence). The comparative analysis of the ChIP-sequence data and DNA microarray data from Bach1-deficient and wild-type (WT) iMEF showed 35 novel candidate target genes of BACH1. Among these genes, five genes (Pparg, Nfia, Ptplad2, Adcy1 and Ror1) were related with lipid metabolism. Bach1-deficient iMEFs showed increased expression of mRNA and protein of PPARγ, which is the key factor of adipogenesis. These cells also showed a concomitant increase in ligand-dependent activation of PPARγ target genes compared with wild-type iMEFs. Moreover, Bach1-deficient iMEFs efficiently differentiated to adipocyte compared with wild-type cells in the presence of PPARγ ligands. Our results suggest that BACH1 regulates expression of adipocyte-related genes including Pparg and potentiates adipocyte differentiation capacity.

Maternal dietary imbalance between omega-6 and omega-3 polyunsaturated fatty acids impairs neocortical development via epoxy metabolites.

Omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFAs) are essential nutrients. Although several studies have suggested that a balanced dietary n-6:n-3 ratio is essential for brain development, the underlying cellular and molecular mechanism is poorly understood. Here, we found that feeding pregnant mice an n-6 excess/n-3 deficient diet, which reflects modern human diets, impairsed neocortical neurogenesis in the offspring. This impaired neurodevelopment occurs through a precocious fate transition of neural stem cells from the neurogenic to gliogenic lineage. A comprehensive mediator lipidomics screen revealed key mediators, epoxy metabolites, which were confirmed functionally using a neurosphere assay. Importantly, although the offspring were raised on a well-balanced n-6:n-3 diet, they exhibited increased anxiety-related behavior in adulthood. These findings provide compelling evidence that excess maternal consumption of n-6 PUFAs combined with insufficient intake of n-3 PUFAs causes abnormal brain development that can have long-lasting effects on the offspring's mental state.

A case of idiopathic type 1 diabetes with subsequent recovery of endogenous insulin secretion despite initial diagnosis of fulminant type 1 diabetes.

Fulminant type 1 diabetes is characterized by remarkably rapid and complete ß-cell destruction. The established diagnostic criteria include the occurrence of diabetic ketosis soon after the onset of hyperglycemic symptoms, elevated plasma glucose with relatively low HbA1c at the first visit, and extremely low C-peptide. Serum C-peptide levels remain extremely low over a prolonged period. A 26-year-old-man with diabetic ketosis was admitted to our hospital. His relatively low HbA1c (7.6%), despite marked hyperglycemia (593 mg/dL) with marked ketosis, indicated abrupt onset. Islet-related autoantibodies were all negative. His data at onset, including extremely low serum C-peptide (0.11 ng/mL), fulfilled the diagnostic criteria for fulminant type 1 diabetes. However, his fasting serum C-peptide levels subsequently showed substantial recovery. While fasting C-peptide stayed below 0.30 ng/mL during the first two months post onset, the levels gradually increased and thereafter fluctuated between 0.60 ng/mL and 0.90 ng/mL until 24 months post onset. By means of multiple daily insulin injection therapy, his glycemic control has been well maintained (HbA1c approximately 6.0%), with relatively small glycemic fluctuations evaluated by continuous glucose monitoring. This clinical course suggests that, despite the abrupt diabetes onset with extremely low C-peptide levels, substantial numbers of ß-cells had been spared destruction and their function later showed gradual recovery. Diabetes has come to be considered a much more heterogeneous disease than the present subdivisions suggest. This case does not fit into the existing concepts of either fulminant type 1 or ketosis-prone diabetes, thereby further highlighting the heterogeneity of idiopathic type 1 diabetes.

Prolyl isomerase Pin1 negatively regulates AMP-activated protein kinase (AMPK) by associating with the CBS domain in the γ subunit.

AMP-activated protein kinase (AMPK) plays a critical role in metabolic regulation. In this study, first, it was revealed that Pin1 associates with any isoform of γ, but not with either the α or the ß subunit, of AMPK. The association between Pin1 and the AMPK γ1 subunit is mediated by the WW domain of Pin1 and the Thr(211)-Pro-containing motif located in the CBS domain of the γ1 subunit. Importantly, overexpression of Pin1 suppressed AMPK phosphorylation in response to either 2-deoxyglucose or biguanide stimulation, whereas Pin1 knockdown by siRNAs or treatment with Pin1 inhibitors enhanced it. The experiments using recombinant Pin1, AMPK, LKB1, and PP2C proteins revealed that the protective effect of AMP against PP2C-induced AMPKα subunit dephosphorylation was markedly suppressed by the addition of Pin1. In good agreement with the in vitro data, the level of AMPK phosphorylation as well as the expressions of mitochondria-related genes, such as PGC-1α, which are known to be positively regulated by AMPK, were markedly higher with reduced triglyceride accumulation in the muscles of Pin1 KO mice as compared with controls. These findings suggest that Pin1 plays an important role in the pathogenic mechanisms underlying impaired glucose and lipid metabolism, functioning as a negative regulator of AMPK.

Identification of Pathogenic Cardiac CD11c+ Macrophages in Nod1-Mediated Acute Coronary Arteritis.

OBJECTIVE: Nod1 is an intracellular pattern recognition receptor for bacterial peptidoglycan fragments. We previously reported that a synthetic Nod1 ligand, FK565, induced acute coronary arteritis in mice similar to that of Kawasaki disease. However, the molecular mechanisms underlying this characteristic inflammation have remained elusive. APPROACH AND RESULTS: We found that CD11c(+)MHC class II(+) cells accumulated in the heart of FK565-treated mice before arteritis development. Morphological features and gene expression signatures of the cardiac CD11c(+)MHC class II(+) cells suggested that this population is closely related to macrophages, and thus, we designated them cardiac CD11c(+) macrophages. Nod1 in nonhematopoietic cells, rather than hematopoietic cells, was required for the increase of cardiac CD11c(+) macrophages and arteritis development. Among nonhematopoietic cells, cardiac endothelial cells produced a large amount of chemokines in response to FK565. Endothelial cell-specific blockade of Nod1 signaling suppressed FK565-induced expression of these chemokines, accumulation of cardiac CD11c(+) macrophages, and subsequent coronary arteritis development. We also found that CCR2(+)Ly6C(hi) inflammatory monocytes in peripheral blood supplied precursors of cardiac CD11c(+) macrophages. CCR2-deficient mice or pertussis toxin-treated mice exhibited decreased numbers of cardiac CD11c(+) macrophages and reduced arteritis. CONCLUSIONS: These results suggest that Ly6C(hi) monocytes are recruited to FK565-activated endothelial cells to generate cardiac CD11c(+) macrophages, which play a pivotal role in the pathogenesis of acute coronary arteritis.

Targeting of senescence and metabolic disorders.

Type 2 diabetes is a major threat to human lifespan, and is caused by tissue dysfunction in insulin sensitive tissues and insulin secreting pancreatic P cells. Prevalence of diabetes is known to increase with age. Tissue dysfunctions in diabetes may be caused in part by a convergence of cellular senescence in adipose tissues and pancreatic p cells. Cellular senescence occurs in response to various cellular stressors, such as telomere erosion, DNA damage and oxidative stress. Senescent adipocytes and pancreatic p cells adopt several unique characteristics including enzymatic activity of senescence associated p galactosidase(SA- f -GAL) and upregulation of cell cycle inhibitors such as p53 and p16. Senotherapies are therapies targeting senescent cells, and is a promising strategy to overcome diabetes.

Par14 protein associates with insulin receptor substrate 1 (IRS-1), thereby enhancing insulin-induced IRS-1 phosphorylation and metabolic actions.

Pin1 and Par14 are parvulin-type peptidyl-prolyl cis/trans isomerases. Although numerous proteins have been identified as Pin1 substrates, the target proteins of Par14 remain largely unknown. Par14 expression levels are increased in the livers and embryonic fibroblasts of Pin1 KO mice, suggesting a compensatory relationship between the functions of Pin1 and Par14. In this study, the association of Par14 with insulin receptor substrate 1 (IRS-1) was demonstrated in HepG2 cells overexpressing both as well as endogenously in the mouse liver. The analysis using deletion-mutated Par14 and IRS-1 constructs revealed the N-terminal portion containing the basic domain of Par14 and the two relatively C-terminal portions of IRS-1 to be involved in these associations, in contrast to the WW domain of Pin1 and the SAIN domain of IRS-1. Par14 overexpression in HepG2 markedly enhanced insulin-induced IRS-1 phosphorylation and its downstream events, PI3K binding with IRS-1 and Akt phosphorylation. In contrast, treating HepG2 cells with Par14 siRNA suppressed these events. In addition, overexpression of Par14 in the insulin-resistant ob/ob mouse liver by adenoviral transfer significantly improved hyperglycemia with normalization of hepatic PEPCK and G6Pase mRNA levels, and gene suppression of Par14 using shRNA adenovirus significantly exacerbated the glucose intolerance in Pin1 KO mice. Therefore, although Pin1 and Par14 associate with different portions of IRS-1, the prolyl cis/trans isomerization in multiple sites of IRS-1 by these isomerases appears to be critical for efficient insulin receptor-induced IRS-1 phosphorylation. This process is likely to be one of the major mechanisms regulating insulin sensitivity and also constitutes a potential therapeutic target for novel insulin-sensitizing agents.