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Query: UNIPROT:P05412 (
c-Jun
)
11,453
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Adiponectin, a major adipose cytokine, plays a crucial role in the inhibition of metabolic syndrome by acting on such cell types as muscle cells and hepatocytes. Furthermore, evidence suggests that
adiponectin
may influence cancer pathogenesis. Adiponectin occurs in non-proteolytic (full-length
adiponectin
: f-
adiponectin
) and proteolytic (globular
adiponectin
: g-
adiponectin
) forms in various oligomeric states. Different forms of
adiponectin
show distinct biological effects through differential activation of downstream signaling pathways. Here we identify
c-Jun
NH(2)-terminal kinase (JNK), and signal transducer and activator of transcription 3 (STAT3) as common downstream effectors of f- and g-
adiponectin
. f- and g-
adiponectin
both stimulate JNK activation in prostate cancer DU145, PC-3, and LNCaP-FGC cells, hepatocellular carcinoma HepG2 cells, and C2C12 myoblasts. Furthermore, both f- and g-
adiponectin
drastically suppress constitutive STAT3 activation in DU145 and HepG2 cells. These suggest that JNK and STAT3 may constitute a universal signaling pathway to mediate
adiponectin
's pathophysiological effects on metabolic syndrome and cancer.
...
PMID:Adiponectin activates c-Jun NH2-terminal kinase and inhibits signal transducer and activator of transcription 3. 1593 15
Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis and varying degrees of necroinflammation. Although chronic oxidative stress, inflammatory cytokines, and insulin resistance have been implicated in the pathogenesis of NAFLD, the mechanisms that underlie the initiation and progression of this disease remain unknown. c-Jun N-terminal kinase (JNK) is activated by oxidants and cytokines and regulates hepatocellular injury and insulin resistance, suggesting that this kinase may mediate the development of steatohepatitis. The presence and function of JNK activation were therefore examined in the murine methionine- and choline-deficient (MCD) diet model of steatohepatitis. Activation of hepatic JNK,
c-Jun
, and AP-1 signaling occurred in parallel with the development of steatohepatitis in MCD diet-fed mice. Investigations in jnk1 and jnk2 knockout mice demonstrated that jnk1, but not jnk2, was critical for MCD diet-induced JNK activation. JNK promoted the development of steatohepatitis as MCD diet-fed jnk1 null mice had significantly reduced levels of hepatic triglyceride accumulation, inflammation, lipid peroxidation, liver injury, and apoptosis compared with wild-type and jnk2 -/- mice. Ablation of jnk1 led to an increase in serum
adiponectin
but had no effect on serum levels of tumor necrosis factor-alpha. In conclusion, JNK1 is responsible for JNK activation that promotes the development of steatohepatitis in the MCD diet model. These findings also provide additional support for the critical mechanistic involvement of JNK1 overactivation in conditions associated with insulin resistance and the metabolic syndrome.
...
PMID:JNK1 but not JNK2 promotes the development of steatohepatitis in mice. 1637 58
In this study, we demonstrated that the two ginger-derived components have a potent and unique pharmacological function in 3T3-L1 adipocytes via different mechanisms. Both pretreatment of 6-shogaol (6S) and 6-gingerol (6G) significantly inhibited the tumor necrosis factor-alpha (TNF-alpha) mediated downregulation of the
adiponectin
expression in 3T3-L1 adipocytes. Our study demonstrate that (1) 6S functions as a PPARgamma agonist with its inhibitory mechanism due to the PPARgamma transactivation, and (2) 6G is not a PPARgamma agonist, but it is an effective inhibitor of TNF-alpha induced
c-Jun
-NH(2)-terminal kinase signaling activation and thus, its inhibitory mechanism is due to this inhibitory effect.
...
PMID:6-Shogaol and 6-gingerol, the pungent of ginger, inhibit TNF-alpha mediated downregulation of adiponectin expression via different mechanisms in 3T3-L1 adipocytes. 1857 75
Low levels of
adiponectin
, a fat-derived hormone, are found to be correlated with coronary heart disease, type 2 diabetes, obesity, and insulin resistance. Conversely, high
adiponectin
levels are predictive of reduced coronary risk in long-term epidemiologic studies. However, the precise role of
adiponectin
in cardiomyocyte function is still not clear. This study was designed to examine the role of
adiponectin
in cardiac contractile function in the db/db model of diabetic obesity. Mechanical properties and intracellular Ca(2+) transients were evaluated in cardiomyocytes from lean control and db/db mice with or without
adiponectin
(10 microg/ml) treatment. Expression and phosphorylation of IRS-1, Akt,
c-Jun
, and
c-Jun
N terminal kinase (JNK) as well as markers of endoplasmic reticulum (ER) stress were evaluated using western blotting. Cardiomyocytes from db/db mice exhibited greater cross-sectional area, depressed peak shortening (PS), and maximal velocity of shortening/re-lengthening as well as prolonged duration of re-lengthening. Consistently, myocytes from db/db mice displayed a reduced electrically stimulated rise in intracellular Ca(2+) and prolonged intracellular Ca(2+) decay, which were abrogated by
adiponectin
treatment. Ratios between phosphorylated
c-Jun
and
c-Jun
as well as phosphorylated IRS-1 and IRS-1 were increased in db/db mice, the effect of which was attenuated by
adiponectin
. Levels of the phosphorylated ER stress makers PERK (Thr980), IRE-1, and eIF2alpha were significantly elevated in db/db mice compared with lean controls, although the effect was unaffected by
adiponectin
. Collectively, our data suggest that
adiponectin
improves cardiomyocyte dysfunction in db/db diabetic obese mice through a mechanism possibly related to
c-Jun
and IRS-1.
...
PMID:Adiponectin improves cardiomyocyte contractile function in db/db diabetic obese mice. 1905 32
Hyperglycemia-induced oxidative stress is a common phenomenon in diabetes. Since oxidative stress depletes
adiponectin
and insulin levels, we investigated whether an upregulated heme oxygenase (HO) system would attenuate the oxidative destruction of
adiponectin
/insulin and improve insulin sensitivity and glucose metabolism in streptozotocin (STZ)-induced type 1 diabetes. HO was upregulated with hemin (15 mg/kg ip) or inhibited with chromium mesoporphyrin (CrMP, 4 micromol/kg ip). Administering hemin to STZ-diabetic rats reduced hyperglycemia and improved glucose metabolism, whereas the HO inhibitor CrMP annulled the antidiabetic effects and/or exacerbated fasting/postprandial hyperglycemia. Interestingly, the antidiabetic effects of hemin lasted for 2 mo after termination of therapy and were accompanied by enhanced HO-1 and HO activity of the soleus muscle, along with potentiation of plasma antioxidants like bilirubin, ferritin, and superoxide dismutase, with corresponding elevation of the total antioxidant capacity. Importantly, hemin abated
c-Jun
NH2-terminal kinase (JNK), a substance known to inhibit insulin biosynthesis, and suppressed markers/mediators of oxidative stress including 8-isoprostane, nuclear-factor (NF)-kappaB, activating protein (AP)-1, and AP-2 of the soleus muscle. Furthermore, hemin therapy significantly attenuated pancreatic histopathological lesions including acinar cell necrosis, interstitial edema, vacuolization, fibrosis, and mononuclear cell infiltration. Correspondingly, hemin increased plasma insulin and potentiated agents implicated in insulin sensitization and insulin signaling such as
adiponectin
, adenosine monophosphate-activated protein kinase (AMPK), cAMP, cGMP, and glucose transporter (GLUT)4, a protein required for glucose uptake. These were accompanied by improved glucose tolerance [intraperitoneal glucose tolerance text (IPGTT)], decreased insulin intolerance [intraperitoneal insulin tolerance test (IPITT)], and reduced insulin resistance [homeostasis model assessment of insulin resistance (HOMA-IR) index], whereas CrMP nullified the hemin-dependent antidiabetic and insulin-sensitizing effects. In conclusion, by concomitantly enhancing insulin and paradoxically potentiating insulin sensitivity, this study unveils a novel, unique, and long-lasting antidiabetic characteristic of upregulating HO with hemin that could be exploited against insulin-resistant and insulin-dependent diabetes.
...
PMID:Heme oxygenase system enhances insulin sensitivity and glucose metabolism in streptozotocin-induced diabetes. 1919 Feb 61
Insulin-mediated signal transduction is positively correlated to
adiponectin
, adenosine monophosphate-activated protein kinase (AMPK), and glucose-transporter-4 (GLUT4) but negatively to oxidative/inflammatory mediators such as nuclear factor-kappaB, activating-protein (AP)-1, AP-2, and
c-Jun
-N-terminal-kinase. Although hemeoxygenase (HO) suppresses oxidative insults, its effects on insulin-sensitizing agents like AMPK and GLUT4 remains unclear and were investigated using Goto-Kakizaki rats (GK), a nonobese insulin-resistant type-2 diabetic model. HO was induced with hemin or inhibited with chromium mesoporphyrin (CrMP). The application of hemin to GK rats evoked a 3-month antidiabetic effect, whereas the HO-inhibitor, CrMP, exacerbated hyperglycemia and nullified insulin-signaling/glucose metabolism. Interestingly, the antidiabetic was accompanied by a paradoxical increase of insulin alongside the potentiation of insulin-sensitizing agents such as
adiponectin
, AMPK, and GLUT4 in the gastrocnemius muscle. Furthermore, hemin enhanced mediators/regulators of insulin signaling like cGMP and cAMP and suppressed oxidative insults by up-regulating HO-1, HO activity, superoxide dismutase, catalase, and the total antioxidant capacity in the gastrocnemius muscle. Accordingly, oxidative markers/mediators including nuclear factor-kappaB, AP-1, AP-2,
c-Jun
-N-terminal-kinase, and 8-isoprostane were abated, whereas CrMP annulled the cytoprotective and antidiabetic effects of hemin. Correspondingly, ip glucose tolerance, insulin tolerance, and homeostasis model assessment insulin resistance analyses revealed improved glucose tolerance, reduced insulin intolerance, enhanced insulin sensitivity, and reduced insulin resistance in hemin-treated GK rats. In contrast, CrMP, abolished the insulin-sensitizing effects and restored and/or exacerbated insulin resistance. Our study unveils a 3-month enduring antidiabetic effect of hemin and unmasks the synergistic interaction among the HO system,
adiponectin
, AMPK, and GLUT4 that could be explored to enhance insulin signaling and improve glucose metabolism in insulin-resistant diabetes.
...
PMID:Up-regulating the hemeoxygenase system enhances insulin sensitivity and improves glucose metabolism in insulin-resistant diabetes in Goto-Kakizaki rats. 1922 89
Hepatic apoptosis is elevated in patients with non-alcoholic steatohepatitis and is correlated with the severity of the disease. Long-chain saturated fatty acids, such as palmitate, induce apoptosis in liver cells. The present study examined
adiponectin
-mediated protection against saturated fatty acid-induced apoptosis in the human hepatoma cell line, HepG2. Cells were cultured in a control media (i.e. without fatty acids) or the same media containing 250 micromol L(-1) of albumin-bound oleate or palmitate for 24 h. The
adiponectin
concentrations used were: 0, 1, 10 or 100 microg mL(-1) (n = 4-6 per treatment). Palmitate and thapsigargin, but not oleate, activated caspase-3 and decreased cell viability in the absence of
adiponectin
. Adiponectin reduced palmitate- and thapsigargin-induced activation of caspase-3 and cell death in a dose-dependent manner. Phosphatidylinositol 3-kinase and AMP-activated protein kinase inhibitors abolished the effects of
adiponectin
. Adiponectin-induced inhibition of palmitate- and thapsigargin-induced apoptosis was not the result of an augmentation in the unfolded protein response or the increased expression of genes encoding the inhibitor of apoptosis proteins, inhibitor of apoptosis protein-2 and X-linked mammalian inhibitor of apoptosis protein. Palmitate and thapsigargin, but not oleate, increased
c-Jun
NH(2) terminal kinase phosphorylation in the absence of
adiponectin
. Adiponectin blocked palmitate- and thapsigargin-induced activation of
c-Jun
NH(2) terminal kinase and reduced apoptosis. These data suggest that
adiponectin
is an important determinant of saturated fatty acid-induced apoptosis in liver cells and may have implications for fatty acid-mediated liver cell injury in
adiponectin
-deficient individuals.
...
PMID:Full-length adiponectin protects hepatocytes from palmitate-induced apoptosis via inhibition of c-Jun NH2 terminal kinase. 1929 Aug 87
The xanthones, alpha- and gamma-mangostin (MG), are major bioactive compounds found in mangosteen and are reported to have antiinflammatory properties in several murine models. Given the association between obesity, chronic low-grade inflammation, and insulin resistance, we examined the effects of alpha- and gamma-MG on markers of inflammation and insulin resistance in primary cultures of newly differentiated human adipocytes treated with lipopolysaccharide (LPS). alpha- and gamma-MG decreased the induction by LPS of inflammatory genes, including tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, IL-8, monocyte chemoattractant protein-1, and Toll-like receptor-2. Moreover, alpha- and gamma-MG attenuated LPS activation of the mitogen-activated protein kinases (MAPK) c-jun NH(2)-terminal kinase, extracellular signal-related kinase, and p38. alpha- and gamma-MG also attenuated LPS activation of
c-Jun
and activator protein (AP)-1 activity. gamma-MG was more effective than alpha-MG on an equimolar basis. Furthermore, gamma-MG but not alpha-MG attenuated LPS-mediated IkappaB-alpha degradation and nuclear factor-kappaB (NF-kappaB) activity. In addition, gamma-MG prevented the suppression by LPS of insulin-stimulated glucose uptake and PPAR-gamma and
adiponectin
gene expression. Taken together, these data demonstrate that MG attenuates LPS-mediated inflammation and insulin resistance in human adipocytes, possibly by inhibiting the activation of MAPK, NF-kappaB, and AP-1.
...
PMID:Xanthones from mangosteen prevent lipopolysaccharide-mediated inflammation and insulin resistance in primary cultures of human adipocytes. 1940 22
In bone marrow, osteoblasts and adipocytes are differentiated from mesenchymal progenitor cells and their differentiation is reciprocally regulated by largely unknown mechanisms. In this study, we investigated downstream signaling cascades of
adiponectin
, a member of the adipocytokine family, in the regulation of osteoblast differentiation. Adiponectin augmented expression of several osteogenic marker genes and increased osteoblast differentiation in mesenchymal progenitor cells. The expression of cyclooxygenase-2 (COX2) was potently increased by
adiponectin
, whereas inhibition of COX2 activity abolished the effect of
adiponectin
on osteogenesis. In addition,
adiponectin
rapidly stimulated p38 mitogen-activated protein kinase via the
adiponectin
receptor, AdipoR1, which resulted in
c-Jun
activation for COX2 expression. Adiponectin also stimulated BMP2 expression in a COX2-dependent manner. Moreover, Runx2, a key osteogenic transcription factor, contributed to the acceleration of osteogenesis in the presence of
adiponectin
. Collectively, the finding that
adiponectin
could promote osteogenesis through an intracellular signaling cascade in mesenchymal progenitor cells suggests that
adiponectin
would be a potential therapeutic target for bone-related diseases.
...
PMID:Adiponectin stimulates osteoblast differentiation through induction of COX2 in mesenchymal progenitor cells. 1952 15
Accumulating clinical evidence indicates that impaired glucose tolerance is a common phenomenon in essential hypertension. Although recent evidence underscores the role of heme-oxygenase (HO) in diabetes, its effects on insulin sensitivity and glucose metabolism in spontaneously hypertensive rat (SHR), a model of essential hypertension with characteristics of metabolic syndrome including insulin resistance/impaired glucose metabolism remains largely unclear. Here we report the effects of the HO inducer, hemin, and the HO blocker, chromium-mesoporphyrin on insulin sensitivity and glucose metabolism in SHRs. Adult SHRs were severely hypertensive but normoglycemic. Hemin therapy lowered blood pressure, increased plasma insulin, decreased glycemia, and enhanced insulin sensitivity by improving glucose tolerance (ip glucose tolerance test) and insulin tolerance (ip insulin tolerance test) but reduced insulin resistance (homeostasis model assessment index). These effects were accompanied by increased gastrocnemius muscle HO-1, HO activity, cGMP, cAMP alongside antioxidants including bilirubin, ferritin, superoxide dismutase, catalase, and the total antioxidant capacity, whereas oxidative/inflammatory mediators like 8-isoprostane, nuclear-factor-kappaB, activating-protein-1, activating-protein-2,
c-Jun
-NH2-terminal-kinase, and heme were abated. Furthermore, hemin reduced proteinuria/albuminuria and enhanced the depressed levels of
adiponectin
, AMP-activated protein-kinase, and glucose transporter-4 in SHRs, suggesting that although SHRs are normoglycemic, insulin signaling and renal function may be impaired. Contrarily, the HO inhibitor chromium-mesoporphyrin exacerbated oxidative stress, aggravated insulin resistance, glucose tolerance, insulin tolerance and nephropathy. Hemin also enhanced HO signaling in Wistar Kyoto and Sprague Dawley rats and increased insulin sensitivity albeit less intensely than in SHRs, suggesting greater selectivity of HO in SHRs with dysfunctional insulin signaling. These results suggest that perturbations of insulin signaling may be a forerunner to hyperglycemia in essential hypertension. By concomitantly potentiating insulin-sensitizing agents, suppressing insulin/glucose intolerance, and abating oxidative stress, HO inducers may prevent metabolic and cardiovascular complications in essential hypertension.
...
PMID:Up-regulating the heme oxygenase system with hemin improves insulin sensitivity and glucose metabolism in adult spontaneously hypertensive rats. 2001 31
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