Trk-fused gene plays a critical role in diet-induced adipose tissue expansion and is also involved in thyroid hormone action.

Mutations in the Trk-fused gene (TFG) cause hereditary motor and sensory neuropathy with proximal dominant involvement, which reportedly has high co-incidences with diabetes and dyslipidemia, suggesting critical roles of the TFG in metabolism as well. We found that TFG expression levels in white adipose tissues (WATs) were elevated in both genetically and diet-induced obese mice and that TFG deletion in preadipocytes from the stromal vascular fraction (SVF) markedly inhibited adipogenesis. To investigate its role in vivo, we generated tamoxifen-inducible adipocyte-specific TFG knockout (AiTFG KO) mice. While a marked down-regulation of the peroxisome proliferator-activated receptor gamma target, de novo lipogenesis (DNL), and mitochondria-related gene expressions were observed in subcutaneous WAT (scWAT) from AiTFG KO mice, these effects were blunted in SVF-derived adipocytes when the TFG was deleted after differentiation into adipocytes, implying cell nonautonomous effects. Intriguingly, expressions of thyroid hormone receptors, as well as carbohydrate responsive element-binding protein ß, which mediates the metabolic actions of thyroid hormone, were drastically down-regulated in scWAT from AiTFG KO mice. Reduced DNL and thermogenic gene expressions in AiTFG KO mice might be attributable to impaired thyroid hormone action in vivo. Finally, when adipocyte TFG was deleted in either the early or the late phase of high-fat diet feeding, the former brought about an impaired expansion of epididymal WAT, whereas the latter caused prominent adipocyte cell death. TFG deletion in adipocytes markedly exacerbated hepatic steatosis in both experimental settings. Collectively, these observations indicate that the TFG plays essential roles in maintaining normal adipocyte functions, including an enlargement of adipose tissue, thyroid hormone function, and thermogenic gene expressions, and in preserving hypertrophic adipocytes.

Auraptene Enhances AMP-Activated Protein Kinase Phosphorylation and Thereby Inhibits the Proliferation, Migration and Expression of Androgen Receptors and Prostate-Specific Antigens in Prostate Cancer Cells.

Citrus hassaku extract reportedly activates AMPK. Because this extract contains an abundance of auraptene, we investigated whether pure auraptene activates AMPK and inhibits proliferation using prostate cancer cell lines. Indeed, auraptene inhibited the proliferation and migration of LNCaP cells and induced phosphorylation of AMPK or its downstream ACC in LNCaP, PC3, and HEK-293 cells, but not in DU145 cells not expressing LKB1. In addition, the mTOR-S6K pathway, located downstream from activated AMPK, was also markedly suppressed by auraptene treatment. Importantly, it was shown that auraptene reduced androgen receptor (AR) and prostate-specific antigen (PSA) expressions at both the protein and the mRNA level. This auraptene-induced downregulation of PSA was partially but significantly reversed by treatment with AMPK siRNA or the AMPK inhibitor compound C, suggesting AMPK activation to, at least partially, be causative. Finally, in DU145 cells lacking the LKB1 gene, exogenously induced LKB1 expression restored AMPK phosphorylation by auraptene, indicating the essential role of LKB1. In summary, auraptene is a potent AMPK activator that acts by elevating the AMP/ATP ratio, thereby potentially suppressing prostate cancer progression, via at least three molecular mechanisms, including suppression of the mTOR-S6K pathway, reduced lipid synthesis, and AR downregulation caused by AMPK activation.

Hepatic Pin1 Expression, Particularly in Nuclei, Is Increased in NASH Patients in Accordance with Evidence of the Role of Pin1 in Lipid Accumulation Shown in Hepatoma Cell Lines.

Our previous studies using rodent models have suggested an essential role for Pin1 in the pathogenesis of non-alcoholic steatohepatitis (NASH). In addition, interestingly, serum Pin1 elevation has been reported in NASH patients. However, no studies have as yet examined the Pin1 expression level in human NASH livers. To clarify this issue, we investigated the expression level and subcellular distribution of Pin1 in liver specimens obtained using needle-biopsy samples from patients with NASH and healthy liver donors. Immunostaining using anti-Pin1 antibody revealed the Pin1 expression level to be significantly higher, particularly in nuclei, in the livers of NASH patients than those of healthy donors. In the samples from patients with NASH, the amount of nuclear Pin1 was revealed to be negatively related to serum alanine aminotransferase (ALT), while tendencies to be associated with other serum parameters such as aspartate aminotransferase (AST) and platelet number were noted but did not reach statistical significance. Such unclear results and the lack of a significant relationship might well be attributable to our small number of NASH liver samples (n = 8). Moreover, in vitro, it was shown that addition of free fatty acids to medium induced lipid accumulation in human hepatoma HepG2 and Huh7 cells, accompanied with marked increases in nuclear Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1), in accordance with the aforementioned observations in human NASH livers. In contrast, suppression of Pin1 gene expression using siRNAs attenuated the free fatty acid-induced lipid accumulation in Huh7 cells. Taken together, these observations strongly suggest that increased expression of Pin1, particularly in hepatic nuclei, contributes to the pathogenesis of NASH with lipid accumulation.

Insulin Sensitivity Initially Worsens but Later Improves With Aging in Male C57BL/6N Mice.

Aging is believed to induce insulin resistance in humans. However, when and how insulin sensitivity changes with aging remains unclear in both humans and mice. In this study, groups of male C57BL/6N mice at 9-19 weeks (young), 34-67 weeks (mature adult), 84-85 weeks (presenile), and 107-121 weeks of age underwent hyperinsulinemic-euglycemic clamp studies with somatostatin infusion under awake and nonrestrained conditions. The glucose infusion rates for maintaining euglycemia were 18.4 ± 2.9, 5.9 ± 1.3, 20.3 ± 7.2, and 25.3 ± 4.4 mg/kg/min in young, mature adult, presenile, and aged mice, respectively. Thus, compared with young mice, mature adult mice exhibited the expected insulin resistance. In contrast, presenile and aged mice showed significantly higher insulin sensitivity than mature adult mice. These age-related changes were mainly observed in glucose uptake into adipose tissue and skeletal muscle (rates of glucose disappearance were 24.3 ± 2.0, 17.1 ± 1.0, 25.5 ± 5.2, and 31.8 ± 2.9 mg/kg/min in young, mature adult, presenile, and aged mice, respectively). Epididymal fat weight and hepatic triglyceride levels were higher in mature adult mice than those in young and aged mice. Our observations indicate that, in male C57BL/6N mice, insulin resistance appears at the mature adult stage of life but subsequently improves markedly. These alterations in insulin sensitivity are attributable to changes in visceral fat accumulations and age-related factors.

Involvement of neuronal and muscular Trk-fused gene (TFG) defects in the development of neurodegenerative diseases.

Trk-fused gene (TFG) mutations have been identified in patients with several neurodegenerative diseases. In this study, we attempted to clarify the effects of TFG deletions in motor neurons and in muscle fibers, using tissue-specific TFG knockout (vMNTFG KO and MUSTFG KO) mice. vMNTFG KO, generated by crossing TFG floxed with VAChT-Cre, showed deterioration of motor function and muscle atrophy especially in slow-twitch soleus muscle, in line with the predominant Cre expression in slow-twitch fatigue-resistant (S) and fast-twitch fatigue-resistant (FR) motor neurons. Consistently, denervation of the neuromuscular junction (NMJ) was apparent in the soleus, but not in the extensor digitorum longus, muscle. Muscle TFG expressions were significantly downregulated in vMNTFG KO, presumably due to decreased muscle IGF-1 concentrations. However, interestingly, MUSTFG KO mice showed no apparent impairment of muscle movements, though a denervation marker, AChRγ, was elevated and Agrin-induced AChR clustering in C2C12 myotubes was inhibited. Our results clarify that loss of motor neuron TFG is sufficient for the occurrence of NMJ degeneration and muscle atrophy, though lack of muscle TFG may exert an additional effect. Reduced muscle TFG, also observed in aged mice, might be involved in age-related NMJ degeneration, and this issue merits further study.

Impact of Plasma Xanthine Oxidoreductase Activity on the Mechanisms of Distal Symmetric Polyneuropathy Development in Patients with Type 2 Diabetes.

To unravel associations between plasma xanthine oxidoreductase (XOR) and diabetic vascular complications, especially distal symmetric polyneuropathy (DSP), we investigated plasma XOR activities using a novel assay. Patients with type 2 diabetes mellitus (T2DM) with available nerve conduction study (NCS) data were analyzed. None were currently taking XOR inhibitors. XOR activity of fasting blood samples was assayed using a stable isotope-labeled substrate and LC-TQMS. JMP Clinical version 5.0. was used for analysis. We analyzed 54 patients. Mean age was 64.7 years, mean body mass index was 26.0 kg/m2, and mean glycated hemoglobin was 9.4%. The logarithmically transformed plasma XOR activity (ln-XOR) correlated positively with hypoxanthine, xanthine, visceral fatty area, and liver dysfunction but negatively with HDL cholesterol. ln-XOR correlated negatively with diabetes duration and maximum intima-media thickness. Stepwise multiple regression analysis revealed ln-XOR to be among selected explanatory factors for various NCS parameters. Receiver operating characteristic curves showed the discriminatory power of ln-XOR. Principal component analysis revealed a negative relationship of ln-XOR with F-waves as well as positive relationships of ln-XOR with hepatic steatosis and obesity-related disorders. Taken together, our results show plasma XOR activity to be among potential disease status predictors in T2DM patients. Plasma XOR activity measurements might reliably detect pre-symptomatic DSP.

Serum HDL-C values: An extremely useful marker for differentiating homozygous lipoprotein lipase deficiency from severe hypertriglyceridemia with other causes in Japan: A meta-analysis based on literatures on Japanese homozygous lipoprotein lipase deficiency.

BACKGROUNDS AND AIM: Lipoprotein lipase (LPL) deficiency is a genetic disorder with a defective gene for lipoprotein lipase, leading to very high triglycerides. In the daily practice it is much more common to come across severely hypertriglyceridemia without homozygous or compound heterozygous LPL deficiency (SHTG). METHODS: We investigated on how to screen homozygous or compound heterozygous LPL deficiency using lipid parameters by meta-analyzing past 20 subjects on this genetic disease reported by Japanese investigators. As a comparison with LPL deficiency, 21 subjects with SHTG from recent two studies were included in this study. RESULTS: Serum HDL-C levels were significantly lower in LPL deficiency than in SHTG (0.38 ± 0.13 vs 0.94 ± 0.28 mmol/L (mean ± SD), p < 0.001), whereas other serum lipids did not differ between the two groups. The ROC curve ± standard error for serum HDL-C for discriminating the two groups was 0.97 ± 0.019. Sensitivity and specificity for distinguishing the two groups were 90% and 95%, respectively when serum HDL-C 0.62 mmol/L was adopted as cut point. CONCLUSION: We found for the first time that serum HDL-C is an extremely useful marker for discriminating LPL deficiency from SHTG in Japanese population.

Pathological Role of Pin1 in the Development of DSS-Induced Colitis.

Inflammatory bowel diseases (IBDs) are serious disorders of which the etiologies are not, as yet, fully understood. In this study, Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1) protein was shown to be dramatically upregulated in the colons of dextran sodium sulfate (DSS)-induced ulcerative colitis model mice. Interestingly, Pin1 knockout (KO) mice exhibited significant attenuation of DSS-induced colitis compared to wild-type (WT) mice, based on various parameters, including body weight, colon length, microscopic observation of the intestinal mucosa, inflammatory cytokine expression, and cleaved caspase-3. In addition, a role of Pin1 in inflammation was suggested because the percentage of M1-type macrophages in the colon was decreased in the Pin1 KO mice while that of M2-type macrophages was increased. Moreover, Pin1 KO mice showed downregulation of both Il17 and Il23a expression in the colon, both of which have been implicated in the development of colitis. Finally, oral administration of Pin1 inhibitor partially but significantly prevented DSS-induced colitis in mice, raising the possibility of Pin1 inhibitors serving as therapeutic agents for IBD.

Central administration of sodium-glucose cotransporter-2 inhibitors increases food intake involving adenosine monophosphate-activated protein kinase phosphorylation in the lateral hypothalamus in healthy rats.

INTRODUCTION: Sodium glucose cotransporter-2 (SGLT2) inhibitors are widely used for diabetes treatment. Although SGLT2 inhibitors have been clinically observed to increase food intake, roles or even the presence of SGLT2 in the central nervous system (CNS) has not been established. We aimed to elucidate potential functions of SGLT2 in the CNS, and the effects of CNS-targeted SGLT2 inhibitors on food intake. RESEARCH DESIGN AND METHODS: We administered three kinds of SGLT2 inhibitors, tofogliflozin, dapagliflozin, and empagliflozin, into the lateral ventricle (LV) in rats and evaluated their effects on food intake. We also evaluated the effects of tofogliflozin administration in the third (3V) and fourth ventricle (4V). Intraperitoneal administration of liraglutide, a glucagon-like peptide-1 (GLP-1) receptor agonist known to suppress food intake, was combined with central tofogliflozin to elucidate whether GLP-1 signaling antagonizes the effect of central SGLT2 inhibitors on food intake. To elucidate potential molecular mechanisms mediating changes in feeding, hypothalamic areas associated with food intake regulation were harvested and analyzed after intracerebroventricular administration (ICV) of tofogliflozin. RESULTS: Bolus ICV injection of tofogliflozin induced a robust increase in food intake starting at 1.5 hours postinjection, and lasting for 5 days. No effect was observed when the same dose of tofogliflozin was administered intraperitoneally. ICV dapagliflozin and empagliflozin significantly enhanced food intake, although the strength of these effects varied among drugs. Food intake was most markedly enhanced when tofogliflozin was infused into the LV. Fewer or no effects were observed with infusion into the 3V or 4V, respectively. Systemic administration of liraglutide suppressed the effect of ICV tofogliflozin on food intake. ICV tofogliflozin increased phosphorylation of AMPK and c-fos expression in the lateral hypothalamus. CONCLUSIONS: SGLT2 inhibitors in the CNS increase food intake. SGLT2 activity in the CNS may regulate food intake through AMPK phosphorylation in the lateral hypothalamic area.

Prolyl isomerase Pin1 interacts with adipose triglyceride lipase and negatively controls both its expression and lipolysis.

BACKGROUND: Lipolysis is essential for the supply of nutrients during fasting, the control of body weight, and remodeling of white adipose tissues and thermogenesis. In the obese state, lipolysis activity and the expression of adipose triglyceride lipase (ATGL), a rate-limiting enzyme, is suppressed. However, the mechanism underlying the regulation of ATGL remains largely unknown. We previously reported that a high-fat diet obviously increases protein levels of the prolyl isomerase, Pin1, in epididymal white adipose tissue (epiWAT) of mice and that Pin1 KO mice are resistant to developing obesity. RESULTS: The present study found that deletion of the Pin1 gene in epiWAT upregulated lipolysis and increased ATGL protein expression by ~2-fold. In addition, it was demonstrated that Pin1 directly associated with ATGL and enhanced its degradation through the ubiquitin proteasome system. Indeed, Pin1 overexpression decreased ATGL expression levels, whereas Pin1 knockdown by siRNA treatment upregulated ATGL protein levels without altering mRNA levels. Moreover, under a high fat diet (HFD)-fed condition, adipocyte-specific Pin1 KO (adipoPin1 KO) mice had 2-fold increase lipolytic activity and upregulated ß-oxidation-related gene expressions. These mice also gained less body weight, and had better glucose metabolism according to the results of glucose and insulin tolerance tests. CONCLUSION: Taken together, these results showed that Pin1 directly interacted with and degraded ATGL via a ubiquitin-proteasome system, consequently causing the downregulation of lipolysis. Therefore, Pin1 could be considered a target for the treatment of dyslipidemia and related disorders.

Detailed analysis of lipolytic enzymes in a Japanese woman of familial lipoprotein lipase deficiency - Effects of pemafibrate treatment.

BACKGROUND: We present here a 72-y-old Japanese woman with lipoprotein lipase (LPL) deficiency and analyzed her lipolytic enzymes in detail before and after pemafibrate treatment. METHODS: She had a serum triglycerides (TG) of 22.6 mmol/l at a medical checkup at the age of 52 y. She was referred to our hospital at the age of 61 y. Her serum lipoprotein lipase (LPL) concentration was extremely low, suggesting the clinical diagnosis of LPL deficiency. She experienced an event of acute pancreatitis at the age of 65 y. RESULTS: Next-generation sequencing analysis revealed a homozygous nonsense mutation in the LPL gene, c.1277G > A (p.Trp409Ter). Her serum TG, LPL and hepatic lipase (HL) concentrations were 15.0 mmol/l, 23 ng/ml and 66 ng/ml, respectively. Fifteen minutes after intravenous heparin injection (30 U/kg), her serum TG, LPL and HL concentrations turned to 14.1 mmol/l, 20 ng/ml and 660 ng/ml, respectively. Eight weeks of pemafibrate treatment (0.2 mg/day) caused a modest reductions in serum TG (15.02 â†’ 13.58 mmol/l) and considerable increases in preheparin HL (66 â†’ 76 ng/ml) and PHP-HL (660 â†’ 1118 ng/ml) concentrations and PHP-HL activities (253 â†’ 369U/l) despite almost no effect on LPL concentrations and activities. CONCLUSIONS: These findings suggest that HL may contribute to the reduction of plasma TG in LPL deficiency.

Development of Pin1 Inhibitors and their Potential as Therapeutic Agents.

The prolyl isomerase Pin1 is a unique enzyme, which isomerizes the cis-trans conformation between pSer/pThr and proline and thereby regulates the function, stability and/or subcellular distribution of its target proteins. Such regulations by Pin1 are involved in numerous physiological functions as well as the pathogenic mechanisms underlying various diseases. Notably, Pin1 deficiency or inactivation is a potential cause of Alzheimer's disease, since Pin1 induces the degradation of Tau. In contrast, Pin1 overexpression is highly correlated with the degree of malignancy of cancers, as Pin1 controls a number of oncogenes and tumor suppressors. Accordingly, Pin1 inhibitors as anti-cancer drugs have been developed. Interestingly, recent intensive studies have demonstrated Pin1 to be responsible for the onset or development of nonalcoholic steatosis, obesity, atherosclerosis, lung fibrosis, heart failure and so on, all of which have been experimentally induced in Pin1 deficient mice. In this review, we discuss the possible applications of Pin1 inhibitors to a variety of diseases including malignant tumors and also introduce the recent advances in Pin1 inhibitor research, which have been reported.

Prolyl isomerase Pin1 in metabolic reprogramming of cancer cells.

Pin1 is one member of a group consisting of three prolyl isomerases. Pin1 interacts with the motif containing phospho-Ser/Thr-Pro of substrates and enhances cis-trans isomerization of peptide bonds, thereby controlling the functions of these substrates. Importantly, the Pin1 expression level is highly upregulated in most cancer cells and correlates with malignant properties, and thereby with poor outcomes. In addition, Pin1 was revealed to promote the functions of multiple oncogenes and to abrogate tumor suppressors. Accordingly, Pin1 is well recognized as a master regulator of malignant processes. Recent studies have shown that Pin1 also binds to a variety of metabolic regulators, such as AMP-activated protein kinase, acetyl CoA carboxylase and pyruvate kinase2, indicating Pin1 to have major impacts on lipid and glucose metabolism in cancer cells. In this review, we focus on the roles of Pin1 in metabolic reprogramming, such as "Warburg effects", of cancer cells. Our aim is to introduce these important roles of Pin1, as well as to present evidence supporting the possibility of Pin1 inhibition as a novel anti-cancer strategy.

Pin1 Plays Essential Roles in NASH Development by Modulating Multiple Target Proteins.

Pin1 is one of the three known prolyl-isomerase types and its hepatic expression level is markedly enhanced in the obese state. Pin1 plays critical roles in favoring the exacerbation of both lipid accumulation and fibrotic change accompanying inflammation. Indeed, Pin1-deficient mice are highly resistant to non-alcoholic steatohepatitis (NASH) development by either a high-fat diet or methionine-choline-deficient diet feeding. The processes of NASH development can basically be separated into lipid accumulation and subsequent fibrotic change with inflammation. In this review, we outline the molecular mechanisms by which increased Pin1 promotes both of these phases of NASH. The target proteins of Pin1 involved in lipid accumulation include insulin receptor substrate 1 (IRS-1), AMP-activated protein kinase (AMPK) and acetyl CoA carboxylase 1 (ACC1), while the p60 of the NF-kB complex and transforming growth factor ß (TGF-ß) pathway appear to be involved in the fibrotic process accelerated by Pin1. Interestingly, Pin1 deficiency does not cause abnormalities in liver size, appearance or function. Therefore, we consider the inhibition of increased Pin1 to be a promising approach to treating NASH and preventing hepatic fibrosis.

Xanthine Oxidase Inhibitor Febuxostat Exerts an Anti-Inflammatory Action and Protects against Diabetic Nephropathy Development in KK-Ay Obese Diabetic Mice.

Hyperuricemia has been recognized as a risk factor for insulin resistance as well as one of the factors leading to diabetic kidney disease (DKD). Since DKD is the most common cause of end-stage renal disease, we investigated whether febuxostat, a xanthine oxidase (XO) inhibitor, exerts a protective effect against the development of DKD. We used KK-Ay mice, an established obese diabetic rodent model. Eight-week-old KK-Ay mice were provided drinking water with or without febuxostat (15 µg/mL) for 12 weeks and then subjected to experimentation. Urine albumin secretion and degrees of glomerular injury judged by microscopic observations were markedly higher in KK-Ay than in control lean mice. These elevations were significantly normalized by febuxostat treatment. On the other hand, body weights and high serum glucose concentrations and glycated albumin levels of KK-Ay mice were not affected by febuxostat treatment, despite glucose tolerance and insulin tolerance tests having revealed febuxostat significantly improved insulin sensitivity and glucose tolerance. Interestingly, the IL-1ß, IL-6, MCP-1, and ICAM-1 mRNA levels, which were increased in KK-Ay mouse kidneys as compared with normal controls, were suppressed by febuxostat administration. These data indicate a protective effect of XO inhibitors against the development of DKD, and the underlying mechanism likely involves inflammation suppression which is independent of hyperglycemia amelioration.

Possible involvement of normalized Pin1 expression level and AMPK activation in the molecular mechanisms underlying renal protective effects of SGLT2 inhibitors in mice.

BACKGROUND: Recently, clinical studies have shown the protective effects of sodium glucose co-transporter2 (SGLT2) inhibitors against progression of diabetic nephropathy, but the underlying molecular mechanisms remain unclear. METHODS: Diabetic mice were prepared by injecting nicotinamide and streptozotocin, followed by high-sucrose diet feeding (NA/STZ/Suc mice). The SGLT2 inhibitor canagliflozin was administered as a 0.03% (w/w) mixture in the diet for 4 weeks. Then, various parameters and effects of canagliflozin on diabetic nephropathy were investigated. RESULTS: Canagliflozin administration to NA/STZ/Suc mice normalized hyperglycemia as well as elevated renal mRNA of collagen 1a1, 1a2, CTGF, TNFα and MCP-1. Microscopic observation revealed reduced fibrotic deposition in the kidneys of canagliflozin-treated NA/STZ/Suc mice. Interestingly, the protein level of Pin1, reportedly involved in the inflammation and fibrosis affecting several tissues, was markedly increased in the NA/STZ/Suc mouse kidney, but this was normalized with canagliflozin treatment. The cells showing increased Pin1 expression in the kidney were mainly mesangial cells, along with podocytes, based on immunohistochemical analysis. Furthermore, it was revealed that canagliflozin induced AMP-activated kinase (AMPK) activation concentration-dependently in CRL1927 mesangial as well as THP-1 macrophage cell lines. AMPK activation was speculated to suppress mesangial cell proliferation and exert anti-inflammatory effects in hematopoietic cells. CONCLUSION: Therefore, we can reasonably suggest that normalized Pin1 expression and AMPK activation contribute to the molecular mechanisms underlying SGLT2 inhibitor-induced suppression of diabetic nephropathy, possibly at least in part by reducing inflammation and fibrotic change.

CXCL12-CXCR4 pathway activates brown adipocytes and induces insulin resistance in CXCR4-deficient mice under high-fat diet.

Brown adipose tissue (BAT) plays a role in energy expenditure and is involved in nutrient metabolism. C-X-C chemokine ligand 12 (CXCL12)-CXCR4 pathway regulates the immune, nervous, and cardiovascular systems and affects the adipose tissue. Here, we investigated the role of this pathway as an activator of BAT. Uncoupling protein 1 mRNA and protein levels and oxygen consumption increased in the brown adipocytes treated with 100 nM CXCL12 peptide. CXCL12-mediated upregulation in P38 and extracellular signal-regulated kinase (ERK) levels was reduced by each inhibitor. Thus, the CXCL12-CXCR4 pathway activated the brown adipocytes through P38 and ERK that acted downstream of this pathway. Mice with CXCR4 defects only in the brown adipocytes were generated and fed with high-fat diet (HFD). Body weight and blood glucose after glucose injection increased in these mice. Long-term exposure to HFD deteriorated blood glucose level after glucose injection. Insulin sensitivity was exacerbated in the knockout mice fed with HFD. Serum lipid parameters and CXCL12 level in knockout mice were similar to those in control mice. These results suggest that the CXCL12-CXCR4 pathway induces brown adipocyte activity and affects nutrient metabolism under HFD load.

Prolyl isomerase Pin1 binds to and stabilizes acetyl CoA carboxylase 1 protein, thereby supporting cancer cell proliferation.

The prolyl isomerase Pin1 expression level is reportedly increased in most malignant tissues and correlates with poor outcomes. On the other hand, acetyl CoA carboxylase 1 (ACC1), the rate limiting enzyme of lipogenesis is also abundantly expressed in cancer cells, to satisfy the demand for the fatty acids (FAs) needed for rapid cell proliferation. We found Pin1 expression levels to correlate positively with ACC1 levels in human prostate cancers, and we focused on the relationship between Pin1 and ACC1. Notably, it was demonstrated that Pin1 associates with ACC1 but not with acetyl CoA carboxylase 2 (ACC2) in the overexpression system as well as endogenously in the prostate cancer cell line DU145. This association is mediated by the WW domain in the Pin1 and C-terminal domains of ACC1. Interestingly, Pin1 deficiency or treatment with Pin1 siRNA or the inhibitor juglone markedly reduced ACC1 protein expression without affecting its mRNA level, while Pin1 overexpression increased the ACC1 protein level. In addition, chloroquine treatment restored the levels of ACC1 protein reduced by Pin1 siRNA treatment, indicating that Pin1 suppressed ACC1 degradation through the lysosomal pathway. In brief, we have concluded that Pin1 leads to the stabilization of and increases in ACC1. Therefore, it is likely that the growth-enhancing effect of Pin1 in cancer cells is mediated at least partially by the stabilization of ACC1 protein, corresponding to the well-known potential of Pin1 inhibitors as anti-cancer drugs.