As shown by recent reports, number of obese people in recent years has been on the increase, there are about 4 million people in Taiwan who are considered to be overweight. World Health Organization (WHO) and United States Center for Disease Control and Prevention (CDC) publicly announced that: Obesity will be the greatest health killer of this century, its damage to personal health is comparable to that of cigarettes. Obesity can cause heart problems, diabetes, artery diseases, high blood pressure, increased chances of cancer occurrence, condition increase and deteriora- tion of Alzheimer¡¦s disease, gall bladder diseases, and shortening of life span. The cause of obesity is due to a fault in adipocytes metabolism functions, and because of this, research into adipocytes molecular regulation is becoming more popular and valued. The process of adipogenesis, the formation of adipose tissue, has become better understood by the studies of several cell types that can be induced to undergo differentiation into adipocytes. The first, and the best characterized, model of adipogenesis in vitro is the 3T3-L1 cell line, a substrain of Swiss 3T3 mouse cell line. 3T3-L1 cells propagated under normal conditions have a fibroblastic phenotype. However, when treated with a combination of dexamethasone, isobutylmethylxanthine (IBMX or MIX) and insulin, 3T3-L1 cells adopt a rounded phenotype and within 5 days begin to accumulate lipids intracellularly in the form of lipid droplets. Treatment of cells with dexamethasone activates the transcription factor CCAAT/enhancer -binding protein £] (C/EBP£]). IBMX inhibits soluble cyclic nucleotide phosphodiesterases and results in increased intracellular cAMP levels. At the nuclear level, treatment with IBMX results in activation of the related transcription factor C/EBP£_. Immediately after exposure to exogenous inducers, the gene expression of C/EBP£] and C/EBP£_ significantly and transiently increases, C/EBP£] and C/EBP£_ may also regulate the expression of C/EBP£\ and PPAR£^. C/EBP£\ and PPAR£^ are considered to play a prominent role in regulating the gene expression of proteins necessary for the development fo the functional mature adipocyte. Within 3 days of exposure to inducers, the cells undergo two rounds of mitosis, termed mitotic clonal expansion, which are required for differentiation. Insulin or insulin-like growth factor-1 promote adipocyte differentiation by activating PI3-kinase and Akt activity. Modulation of the activity of the forkhead transcription factor Foxo1 appears to be necessary for insulin to promote adipocyte differentiation. C/EBP£\ and PPAR£^ direct the final phase of adipogenesis by activating expression of adipocyte-specific genes, such as fatty acid synthetase, fatty acid binding protein, leptin and adiponectin. The identification of regulators of adipogenesis raises the prospect of preventing or reversing obesity through pharmacological means. My research is aimed at investigating the adipocytes differentiation and regeneration adaptive mechanisms of mice 3T3L-1 preadipocytes and human processed lipoaspirate cells (PLA). By using adipocytes culture techniques in conjunction with adipocytes growth induction and gene delivery techniques to further study obesity related genes, POMC and PTEN, and downstream regulators , PPAR£^ and Adiponectin, in regards to their roles in the process of adipocytes differentiation.

Macrophage-conditioned medium (MacCM) inhibits the differentiation of rodent and human preadipocytes. Previous studies report that murine J774A.1-MacCM inhibits clonal expansion (early required phase of adipogenesis), including Rb phosphorylation. I hypothesized that MacCM induced alterations in cyclins and/or cyclin-dependent kinases (CDKs) were responsible for impairing Rb phosphorylation. My first objective was to assess the effect of J774A.1-MacCM on CDK4, CDK2, and their regulatory cyclins. Murine 3T3-L1 preadipocytes were differentiated with control medium or J774A.1-MacCM. Expression of cyclin D and A was inhibited by J774A.1-MacCM. Inhibition of cyclin A expression was associated with reduced differentiation-induced CDK2 activity. My second objective was to assess the expression patterns of cell cycle proteins in differentiating human abdominal subcutaneous preadipocytes, which do not undergo clonal expansion in culture. Cyclin E expression increased with differentiation. THP-1-MacCM (a human macrophage cell line) further enhanced this increase. My studies suggest MacCM leads to alterations in cyclin/CDK regulation during adipogenesis in murine and human preadipocyte models.

Macrophage-conditioned medium (MacCM) inhibits the differentiation of rodent and human preadipocytes. Previous studies report that murine J774A.1-MacCM inhibits clonal expansion (early required phase of adipogenesis), including Rb phosphorylation. I hypothesized that MacCM induced alterations in cyclins and/or cyclin-dependent kinases (CDKs) were responsible for impairing Rb phosphorylation. My first objective was to assess the effect of J774A.1-MacCM on CDK4, CDK2, and their regulatory cyclins. Murine 3T3-L1 preadipocytes were differentiated with control medium or J774A.1-MacCM. Expression of cyclin D and A was inhibited by J774A.1-MacCM. Inhibition of cyclin A expression was associated with reduced differentiation-induced CDK2 activity. My second objective was to assess the expression patterns of cell cycle proteins in differentiating human abdominal subcutaneous preadipocytes, which do not undergo clonal expansion in culture. Cyclin E expression increased with differentiation. THP-1-MacCM (a human macrophage cell line) further enhanced this increase. My studies suggest MacCM leads to alterations in cyclin/CDK regulation during adipogenesis in murine and human preadipocyte models.

Macrophage-conditioned medium (MacCM) inhibits the differentiation of rodent and human preadipocytes. Previous studies report that murine J774A.1-MacCM inhibits clonal expansion (early required phase of adipogenesis), including Rb phosphorylation. I hypothesized that MacCM induced alterations in cyclins and/or cyclin-dependent kinases (CDKs) were responsible for impairing Rb phosphorylation. My first objective was to assess the effect of J774A.1-MacCM on CDK4, CDK2, and their regulatory cyclins. Murine 3T3-L1 preadipocytes were differentiated with control medium or J774A.1-MacCM. Expression of cyclin D and A was inhibited by J774A.1-MacCM. Inhibition of cyclin A expression was associated with reduced differentiation-induced CDK2 activity. My second objective was to assess the expression patterns of cell cycle proteins in differentiating human abdominal subcutaneous preadipocytes, which do not undergo clonal expansion in culture. Cyclin E expression increased with differentiation. THP-1-MacCM (a human macrophage cell line) further enhanced this increase. My studies suggest MacCM leads to alterations in cyclin/CDK regulation during adipogenesis in murine and human preadipocyte models.

Macrophage-conditioned medium (MacCM) inhibits the differentiation of rodent and human preadipocytes. Previous studies report that murine J774A.1-MacCM inhibits clonal expansion (early required phase of adipogenesis), including Rb phosphorylation. I hypothesized that MacCM induced alterations in cyclins and/or cyclin-dependent kinases (CDKs) were responsible for impairing Rb phosphorylation. My first objective was to assess the effect of J774A.1-MacCM on CDK4, CDK2, and their regulatory cyclins. Murine 3T3-L1 preadipocytes were differentiated with control medium or J774A.1-MacCM. Expression of cyclin D and A was inhibited by J774A.1-MacCM. Inhibition of cyclin A expression was associated with reduced differentiation-induced CDK2 activity. My second objective was to assess the expression patterns of cell cycle proteins in differentiating human abdominal subcutaneous preadipocytes, which do not undergo clonal expansion in culture. Cyclin E expression increased with differentiation. THP-1-MacCM (a human macrophage cell line) further enhanced this increase. My studies suggest MacCM leads to alterations in cyclin/CDK regulation during adipogenesis in murine and human preadipocyte models.

For the first time in human history, more people worldwide suffer from obesity than are undernourished. Numerous health complications are associated with obesity including cardiovascular disease, Type 2 Diabetes, cancers of reproductive tissues, stroke, depression, anxiety disorders, and Alzheimer’s disease. A deeper understanding of the anti-adipogenic effects and mechanism of action of sesquiterpene lactones may have pharmacological import in the continuing search for therapeutic modalities to ameliorate the effects of this global obesity epidemic. Dehydroleucodine (DhL), 11,13-dihydro-dehydroleucodine (DH-DhL), and dehydroparashin-B (DhP), sesquiterpene lactones extracted from or derived from compounds extracted from Artemisia douglasiana, were investigated for their anti-adipogenic effects on 3T1-L1 preadipocytes. Dehydroleucodine inhibited the expression of C/EBPa and PPARg, and also strongly blocked the expression of C/EBPβ, an early stage biomarker of early adipogenesis, in a concentration-dependent manner. Dehydroleucodine arrested the cell cycle at the G0/G1 phase, increased p27 and decreased both cyclins A and D and their partners (e.g., CDK2 and CDK4). Furthermore, DhL downregulated expression of histone demethylase JMJD2 as well as repressed the expression of histone methyltransferase MLL4, which in turn diminished the expression of C/EBPb and PPARg, respectively. 11,13-dihydro-dehydroleucodine blocked the accumulation of lipid droplets and inhibited the expression of PPARγ and C/EBPβ. Collectively, the results indicate that the inhibition of early stage preadipocyte differentiation by DH-DhL may be associated with cell cycle arrest at the G0/G1 phase. Dehydroparashin-B significantly decreased the accumulation of lipid content and downregulated the expression of CEBPβ, PPARγ and CEBPα as well as FAS. Interestingly, the addition of DhP inhibited the number as well as the size of the lipid droplets during the differentiation of 3T3-L1 preadipocytes. Taken together, this data suggests that DhP has an important inhibitory effect on cellular pathways regulating adipocyte differentiation.