Syndromal acanthosis nigricans is associated with cellular resistance to the action of insulin and other endocrinopathies. In the insulin resistant state, increased insulin binds to the receptors of insulin-like growth factors (IGFs). IGFs are growth prompting peptides, which act as direct mitogens on cells containing the receptors. Through these actions, increased cellular growth and metabolism cause the skin lesions of acanthosis nigricans. Hyperandrogenism is also found in syndromal acanthosis nigricans patients. When associated with insulin resistance, these states are proportionally related. Increased insulin prompts the synthesis of androgen and conversely, increased androgen elevates the insulin resistance. We present three cases of syndromal acanthosis nigricans with hyperpigmented skin lesions and obesity. Laboratory findings demonstrated normal fasting blood suga levels with increased insulin and C-peptide levels and decreased insulin receptors. The oral glucose tolerance test was normal. We suggest that these patients were in an insulin resistant state. Skin biopsies from the axilla in all three cases showed hyperkeratosis, irregular acanthosis and upward projection of dermal papillae as finger like fashion. Thus all three cases represent syndromal acanthosis nigricans associated with an insulin resistant state based on clinical, histopathological, and laboratory findings. The three patients were treated with dietary control.
Acanthosis Nigricans* ; Axilla ; Biopsy ; C-Peptide ; Fasting ; Fingers ; Glucose Tolerance Test ; Humans ; Hyperandrogenism ; Insulin Resistance* ; Insulin* ; Metabolism ; Mitogens ; Obesity ; Peptides ; Receptor, Insulin ; Skin ; Somatomedins

Phospholipase Cgamma1 (PLCgamma1) plays an important role in controlling cellular proliferation and differentiation. PLCgamma1 is overexpressed in some tumors, and its overexpression induces solid tumors in nude mice. However, the regulatory mechanisms underlying PLCgamma1-induced cell proliferation are not fully understood. Here we show that overexpression of PLCgamma1 highly phosphorylated glycogen synthase kinase-3beta (GSK-3beta) at serine-9 in 3Y1 fibroblasts. Inhibition of protein kinase C (PKC)s with GF109203X abrogated GSK-3beta phosphorylation by PLCgamma1. We also found that steady-state level of cyclin D1 protein, but not cyclin D1 mRNA, was highly elevated in response to serum stimulation in PLCgamma1-transfected cells as compared with vector-transfected cells. Since GSK-3beta is involved in cyclin D1 proteolysis in response to mitogenic stimulation, PLCgamma1-mediated GSK-3beta phosphorylation may function as a regulation of cyclin D1 accumulation in PLCgamma1-overexpressing cells.
Animals ; Cyclin D1/metabolism ; Epidermal Growth Factor/pharmacology ; Fibroblasts ; Gene Expression ; Glycogen Synthase Kinase 3/chemistry/*metabolism ; Mitogens/pharmacology ; Phospholipase C/genetics/*metabolism ; Phosphorylation/drug effects ; Phosphoserine/*metabolism ; Protein Kinase C/antagonists & inhibitors/*metabolism ; Rats ; Signal Transduction

BACKGROUNDHuman urotensin II (UII) is the most potent mammalian vasoconstrictor identified so far. Our previous study showed that UII is a potent mitogen of airway smooth muscle cells (ASMC) inducing ASMC proliferation in a dose-dependent manner. The signal transduction pathway of UII mitogenic effect remains to be clarified. This study was conducted to investigate the signal transduction pathway in the proliferation of ASMC induced by UII.

METHODSIn primary cultures of rat ASMCs, activities of protein kinase C (PKC), mitogen-activated protein kinase (MAPK) and calcineurin (CaN) induced by UII were measured. The effect of CaN on PKC and MAPK was studied by adding cyclosporin A (CsA), a specific inhibitor of CaN. Using H7 and PD98059, inhibitors of PKC and MAPK, respectively, to study the effect of PKC and MAPK on CaN. The cytosolic free calcium concentration induced by UII was measured using Fura-2/AM.

RESULTSUII 10(-7) mol/L stimulated ASMC PKC and MAPK activities by 44% and 24% (P < 0.01), respectively, after incubating for 20 minutes. It increased CaN activity in a time-dependent manner, being 1.68 times as that of control for 24 hours (P < 0.01). It promoted the cytosolic free calcium concentration increase of 18% (P < 0.01). CsA 10(-6) mol/L and H7 50 micromol/L inhibited UII-stimulated CaN activity by 45% (P < 0.01) and 21% (P < 0.05), respectively, while PD98059 50 micromol/L had no effect on CaN activity (P > 0.05). CsA 10(-6) mol/L inhibited UII-stimulated PKC activity by 14% (P < 0.05), while having no effect on MAPK activity (P > 0.05).

CONCLUSIONSUII increases cytosolic free calcium concentration and activates PKC, MAPK and CaN. The signal transduction pathway between PKC and CaN has cross-talk.

Animals ; Calcineurin ; metabolism ; Cells, Cultured ; Enzyme Activation ; Mitogen-Activated Protein Kinases ; metabolism ; Mitogens ; pharmacology ; Myocytes, Smooth Muscle ; cytology ; Protein Kinase C ; metabolism ; Rats ; Signal Transduction ; physiology ; Trachea ; cytology ; Urotensins ; pharmacology

We have shown that hyaluronic acid stimulates the proliferation of quiescent NIH 3T3 cells. We have shown that treatment of 1 mg/ml hyaluronic acid results in increase of tyrosine phosphorylation of two proteins, MW 124 kDa and 60 kDa as detected by anti-tyrosine antibodies by Western blot analysis. Maximum phosphorylation occurred within 2 h after addition of 1 mg/ml hyaluronic acid. Stimulation of proliferation was also accompanied by increase in c-Myc protein, which was inhibited by amlloride, an inhibitor of Na+/H+ antiporter and EGTA and increase in the steady state level of pRb, the RB gene product. These results suggest that the intracellular signal transduction pathways that mediate the stimulatory effects of hyaluronic acid on cellular proliferation are similar to those of growth factors.
3T3 Cells ; Amiloride/pharmacology ; Animal ; Cell Division ; Dose-Response Relationship, Drug ; Egtazic Acid/pharmacology ; Hyaluronic Acid/pharmacology* ; Mice ; Mitogens/pharmacology* ; Phosphoproteins/metabolism* ; Phosphorylation ; Proto-Oncogene Proteins c-myc/metabolism* ; Retinoblastoma Protein/metabolism* ; Signal Transduction ; Sodium-Hydrogen Antiporter/antagonists & inhibitors ; Tyrosine

Both adaptive and deleterious responses of cells to ethanol are likely triggered by short-term interactions of the cells with ethanol. Many studies have demonstrated the direct effect of ethanol on growth factor-stimulated cell proliferation. Using Swiss 3T3 cells whose growth was inhibited by ethanol in a concentration-dependent manner, we further investigated the molecular mechanisms of acute ethanol treatment by examining its effect on EGF- and PDGF-mediated cellular signaling systems for the mitogenic function. Tyrosine autophosphorylation of the growth factor receptors was partially prevented by ethanol in intact cells. When ethanol was included before or after EGF stimulation, no effect on the receptor signaling was observed. Here we also report that ethanol inhibits activation of ERK induced by both EGF and PDGF. EGF-induced JNK activation was reduced but PDGF-induced rapid JNK activation was delayed by the addition of ethanol. The balance between its inhibitory and stimulatory effect on the signaling molecules might determine the rate of cell growth.
3T3 Cells ; Animal ; Cell Division/drug effects ; Drug Interactions ; Epidermal Growth Factor/pharmacology* ; Ethanol/pharmacology* ; Mice ; Mitogen-Activated Protein Kinases/metabolism ; Mitogens/pharmacology* ; Platelet-Derived Growth Factor/pharmacology* ; Signal Transduction/drug effects

The mechanisms of estrogen and progesterone in human cutaneous pigmentation are largely unknown. The molecular identification of estrogen receptor (ER) and progesterone receptor (PR) in the human melanocytes is of great importance to understand the mechanisms. We performed immunocytochemistry analysis and demonstrated that ER and PR were expressed in the cytoplasms and nuclei of human melanocytes. Reverse transcriptase-polymerase chain reaction (RT-PCR) and sequence analysis confirmed the expression of ER and PR at the transcriptional level. Despite of the presence of ER and PR, the physiological and pregnant levels of estrogen and progesterone showed inconsistent effects on the proliferation and tyrosinase activity of cultured human melanocytes. These results suggest that human melanocytes express ER and PR, which have a donor-specific action in human pigmentation. Further studies are needed to elucidate the induction mechanism and functions of these receptors, and the role of estrogen and progesterone in melanocytes.
Adult ; Cells, Cultured ; Estrogens/*pharmacology ; Gene Expression ; Humans ; Melanocytes/cytology/*drug effects/metabolism ; Mitogens/pharmacology ; Organ Culture Techniques ; Progesterone/*pharmacology ; Receptors, Estrogen/genetics/*metabolism ; Receptors, Progesterone/genetics/*metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Skin/drug effects ; Skin Pigmentation/drug effects ; Tissue Donors

This study aims to decipher the mechanism underlying the effect of Shaofu Zhuyu Decoction on endometriosis(EMT)-associated dysmenorrhea in rats with the syndrome of cold coagulation and blood stasis based on mitogen-and stress-activated protein kinase 1/2(MSK1/2).We employed a random number table to randomly assign SPF female non-pregnant rats into the sham group, and treated the rest rats with autologous transplantation+refrigerator freezing for the modeling of the syndrome of cold coagulation and blood stasis.The modeled rats were then randomly assigned into the control group and high-, medium-and low-dose Shaofu Zhuyu Decoction groups.The rats in the low-, medium-, and high-dose decoction groups were respectively administrated with 9, 4.5, and 2.3 g·kg~(-1) decoction through gavage once a day for 2 consecutive weeks, and those in the control group were administrated with 0.24 mg·kg~(-1) gestrinone through gavage once every 3 days for 2 weeks.After that, the size of ectopic focus in each rat was measured via laparotomy.Enzyme-linked immunosorbent assay(ELISA) was adopted to determine the expression of interleukin(IL)-6, IL-10, prostaglandin E2(PGE2), tumor necrosis factor-α(TNF-α).Western blot was employed to determine the protein levels of MSK1/2 and dual-specificity phosphatase 1(DUSP1) and real-time quantitative polymerase chain reaction(RT-PCR) to determine the mRNA levels of the two genes in rat eutopic endometrial tissue.Compared with the sham group, the model group showed increased levels of IL-6, PGE2, and TNF-α while decrease level of IL-10 in the serum(P<0.01).Compared with the model group, the high-and medium-dose decoction groups and the gestrinone group had declined levels of IL-6, PGE2, and TNF-α while risen level of IL-10 in the serum(P<0.01).The model group had lower protein levels and mRNA levels of MSK1/2 and DUSP1 in the eutopic endometrial tissue than the sham group(P<0.01). The high-and medium-dose decoction groups and the gestrinone group had higher protein and mRNA levels of MSK1/2 and DUSP1 in the eutopic endometrial tissue than the model group(P<0.01).The results indicated that Shaofu Zhuyu Decoction can regulate the abnormal expression of pro-inflammatory cytokines TNF-α, IL-6, and PGE2 and anti-inflammatory cytokines IL-10 and DUSP1 via MSK1/2 to alleviate EMT-associated dysmenorrhea in rats with the syndrome of cold coagulation and blood stasis.
Animals ; Female ; Rats ; Anti-Inflammatory Agents/therapeutic use* ; Cytokines ; Dinoprostone ; Drugs, Chinese Herbal/therapeutic use* ; Dual-Specificity Phosphatases ; Dysmenorrhea/genetics* ; Endometriosis/genetics* ; Gestrinone/therapeutic use* ; Interleukin-10 ; Interleukin-6 ; Mitogen-Activated Protein Kinase 8/therapeutic use* ; Mitogens/therapeutic use* ; RNA, Messenger ; Tumor Necrosis Factor-alpha/metabolism*

Germanium biotite (GB) is an aluminosilicate mineral containing 36 ppm germanium. The present study was conducted to better understand the effects of GB on immune responses in a mouse model, and to demonstrate the clearance effects of this mineral against Porcine reproductive and respiratory syndrome virus (PRRSV) in experimentally infected pigs as an initial step towards the development of a feed supplement that would promote immune activity and help prevent diseases. In the mouse model, dietary supplementation with GB enhanced concanavalin A (ConA)-induced lymphocyte proliferation and increased the percentage of CD3+CD8+ T lymphocytes. In pigs experimentally infected with PRRSV, viral titers in lungs and lymphoid tissues from the GB-fed group were significantly decreased compared to those of the control group 12 days post-infection. Corresponding histopathological analyses demonstrated that GB-fed pigs displayed less severe pathological changes associated with PRRSV infection compared to the control group, indicating that GB promotes PRRSV clearance. These antiviral effects in pigs may be related to the ability of GB to increase CD3+CD8+ T lymphocyte production observed in the mice. Hence, this mineral may be an effective feed supplement for increasing immune activity and preventing disease.
Aluminum Silicates/administration & dosage/*therapeutic use ; Animal Feed/analysis ; Animals ; Antigens, CD3/metabolism ; Antigens, CD8/metabolism ; Antiviral Agents/administration & dosage/*therapeutic use ; Concanavalin A/metabolism ; Dietary Supplements/analysis ; Disease Models, Animal ; Ferrous Compounds/administration & dosage/*therapeutic use ; Germanium/administration & dosage/*therapeutic use ; Lung/immunology/virology ; Lymphocyte Activation/drug effects ; Lymphocytes/cytology/drug effects ; Lymphoid Tissue/immunology/virology ; Mice ; Mitogens/metabolism ; Porcine Reproductive and Respiratory Syndrome/*drug therapy/pathology/virology ; Porcine respiratory and reproductive syndrome virus/*drug effects ; Swine

The mechanism underlying T cell-mediated fulminant hepatitis is not fully understood. In this study, we investigated whether myeloid derived suppressor cells (MDSCs) could prevent the concanavalin A (ConA)-induced hepatitis through suppressing T cell proliferation. We observed an increase in the frequencies of MDSCs in mouse spleen and liver at early stage of ConA treatment, implicating that the MDSCs might be involved in the initial resistance of mice against ConA-mediated inflammation. Subpopulation analysis showed that the MDSCs in liver of ConA-induced mice were mainly granulocytic MDSCs. Adoptive transfer of the bone marrow-derived MDSCs into ConA-treated mice showed that the MDSCs migrated into the liver and spleen where they suppressed T cell proliferation through ROS pathway. In addition, the frequencies of MDSCs in mice were also significantly increased by the treatment with immune suppressor glucocorticoids. Transfer of MDSCs into the regulatory T cell (Treg)-depleted mice showed that the protective effect of MDSCs on ConA-induced hepatitis is Treg-independent. In conclusion, our results demonstrate that MDSCs possess a direct protective role in T cell-mediated hepatitis, and increasing the frequency of MDSCs by either adoptive transfer or glucocorticoid treatment represents a potential cell-based therapeutic strategy for the acute inflammatory disease.
Adoptive Transfer ; Animals ; Blotting, Western ; Bone Marrow Cells ; immunology ; CD11b Antigen ; immunology ; metabolism ; Cell Movement ; immunology ; Cell Proliferation ; Chemical and Drug Induced Liver Injury ; etiology ; immunology ; prevention & control ; Concanavalin A ; toxicity ; Dexamethasone ; pharmacology ; Flow Cytometry ; Glucocorticoids ; pharmacology ; Liver ; immunology ; pathology ; Male ; Mice, Inbred C57BL ; Mitogens ; administration & dosage ; toxicity ; Myeloid Cells ; immunology ; metabolism ; transplantation ; Receptors, Chemokine ; immunology ; metabolism ; Spleen ; immunology ; pathology ; T-Lymphocytes ; immunology ; T-Lymphocytes, Regulatory ; immunology