Prolyl Isomerase Pin1 Protects Mice from Endotoxin Shock

Prolyl isomerase Pin1 may be involved in innate immunity against microbial infection, but the mechanism how Pin1 controls the innate immunity is poorly understood.Injection of lipopolysaccharide (LPS) into the mice induces inflammatory pulmonary disorder and sometimes the serious damages lead to death. Comparing to the wild-type (WT) mice, the Pin1⁻/⁻ mice showed more serious damages in lung and the lower survival rate after the LPS injection. We compared the levels of typical inflammatory cytokines. Pin1⁻/⁻ mice overreacted to the LPS injection to produce inflammatory cytokines, especially IL-6 more than WT mice. We showed that Pin1 binds phosphorylated PU.1 and they localize together in a nucleus. These results suggest that Pin1 controls the transcriptional activity of PU.1 and suppresses overreaction of macrophage that causes serious damages in lung.Pin1 may protect the mice from serious inflammation by LPS injection by attenuating the increase of IL-6 transcription of the mouse macrophages

Prolyl Isomerase Pin1 Directly Regulates Calcium/Calmodulin-Dependent Protein Kinase II Activity in Mouse Brains

Calcium/calmodulin-dependent protein kinase II (CaMKII) is abundant in the brain and functions as a mediator of calcium signaling. We found that the relative activity of CaMKII was significantly lower in the WT mouse brains than in the Pin1-/- mouse brains. Pin1 binds to phosphorylated CaMKII and weakens its activity. For this reason, the phosphorylation level of tau in the presence of Pin1 is lower than that in the absence of Pin1, and microtubule polymerization is not downregulated by CaMKII when Pin1 is present. These results suggest a novel mechanism of action of Pin1 to prevent neurodegeneration

Prolyl Isomerase Pin1 Regulates Mouse Embryonic Fibroblast Differentiation into Adipose Cells

isomerase, Pin1, regulates insulin signal transduction. Pin1 reduces responses to insulin stimulation by binding CRTC2 (CREB-regulated transcriptional co-activator 2) and PPARγ (peroxisome prolifereator- activated receptor γ), but conversely enhances insulin signaling by binding IRS-1 (insulin receptor substrate-1), Akt kinase, and Smad3. Therefore, it is still unclear whether Pin1 inhibits or enhances adipose cell differentiation. mice was restored by increasing expression of Pin1. We found that Pin1 binds to phosphoThr172- and phosphoSer271-Pro sites in CREB suppress the activity in COS-7 cells.Pin1 enhanced the uptake of triglycerides and the differentiation of MEF cells into adipose cells in response to insulin stimulation. Results of this study suggest that Pin1 down-regulation could be a potential approach in obesity-related dysfunctions, such as high blood pressure, diabetes, non-alcoholic steatohepatitis

Brown Algae Polyphenol, a Prolyl Isomerase Pin1 Inhibitor, Prevents Obesity by Inhibiting the Differentiation of Stem Cells into Adipocytes

<div><p>Background</p><p>While screening for an inhibitor of the peptidyl prolyl cis/trans isomerase, Pin1, we came across a brown algae polyphenol that blocks the differentiation of fibroblasts into adipocytes. However, its effectiveness on the accumulation of fat in the body has never been studied.</p><p>Methodology/Principal Findings</p><p>Oral administration of brown algae polyphenol to mice fed with a high fat diet, suppressed the increase in fat volume to a level observed in mice fed with a normal diet. We speculate that Pin1 might be required for the differentiation of stem cell to adipocytes. We established wild type (WT) and <i>Pin1</i>^<i>-/-</i> (Pin1-KO) adipose-derived mesenchymal stem cell (ASC) lines and found that WT ASCs differentiate to adipocytes but Pin1-KO ASCs do not.</p><p>Conclusion and Significance</p><p>Oral administration of brown algae polyphenol, a Pin1 inhibitor, reduced fat buildup in mice. We showed that Pin1 is required for the differentiation of stem cells into adipocytes. We propose that oral intake of brown algae polyphenol is useful for the treatment of obesity.</p></div

Comparison of ASC differentiation to adipocytes.

<p>Comparison of adipocyte differentiation between the WT (<i>Pin1</i>^<i>+/+</i><i>; p53</i>^<i>-/-</i>) ASC and Pin1-KO (<i>Pin1</i>^<i>-/-</i><i>; p53</i>^<i>-/-</i>) ASC, and Pin1-KO ASC rescued with the lentiviral Pin1 cDNA. The wild type ASC, the Pin1-KO ASC- infected with Mock and the Pin1-KO ASC- infected with lentiviral Pin1 cDNA were cultured in DMEM containing 0.5 mM 3-isobutyl-1-methylxanthine, 1 μM dexamethasone, and 1.7 μM insulin for 0–16 days. ASCs were treated with 4% paraformaldehyde and 60% 2-propanol, and then stained with Oil Red O. The images of the oil red O-stained cells on 0, 4, 7, 10, 13, and 16 days after treatment with the differentiation reagent are shown.</p

Comparison of obesity marker levels in sera between mouse groups (n = 5 each).

<p>Leptin (ng/ml), total cholesterol (mg/dl), free fatty acids (mEq/L), neutral fat (mg/dl), and adiponectin (ng/ml) in the serum of each mouse, 1: high fat diet + brown algae polyphenol, 2: high fat diet, 3: normal diet.</p

Primer List for the Real-time PCR

<p>Primer List for the Real-time PCR</p

Effect of brown algae polyphenol on the differentiation of NIH3T3-L1 cells to adipocytes.

<p><b>A) The amount of the intracellular lipid stained with oil red O.</b> NIH3T3-L1 cells were cultured in DMEM containing 0.5 mM 3-isobutyl-1-methylxanthine, 1 μM dexamethasone, and 1.7 μM insulin with 0 (diamond), 50 (square), 100 (triangle), and 150 μg/ml (x) brown algae polyphenol for 0–8 days. NIH3T3-L1 cells were treated with 4% paraformaldehyde and 60% 2-propanol and then stained with Oil Red O. The amount of oil red O extracted from the cells was determined three times by measuring absorbance at 550 nm (means ± SEM). <b>B) PCR analysis of adipocyte biomarker</b> mRNA levels. NIH3T3-L1 cells were cultured with 0, 50, 100, and 150 μg/ml of brown algae polyphenol for 0–8 days. The mRNA levels of PPARγ, C/EBPα, Glut4, FABP4, and LPL in these cells were compared by PCR.</p