ROLE OF VITAMIN-D3 AND RETINOIC ACID IN A HUMAN THP-1 MACROPHAGE MODEL OF MYCOBACTERIUM TUBERCULOSIS INFECTION

Mycobacterium tuberculosis (Mtb) replicates within the human macrophages and we investigated the activating effects of retinoic acid (RA) and vitamin D3 (VD) on macrophages in relation to the viability of Mtb. A combination of these vitamins (RAVD) enhanced the receptors on THP-1 macrophage (Mannose receptor and DC-SIGN) that increased mycobacterial uptake but inhibited thesubsequent intracellular growth of Mtb by inducing reactive oxygen species (ROS) and autophagy. RAVD also enhanced antigen presenting and homing receptors in THPs that suggested an activated phenotype for THPs following RAVD treatment. RAVD mediated activation was also associated with a marked phenotypic change in Mtb infected THPs that fused with adjacent cells to formmultinucleate giant cells (MNGCs). Typically MNGCs occurred over 30 days of in vitro culture and contained non-replicating persisting Mtb for as long as 60 days in culture. We propose that the RAVD mediated inhibition of replicating Mtb leading to persistence of non-replicating Mtb within THPs may provide a novel human macrophage model simulating formation of MNGCs in humanlungs.

Family Preservation Journal, 2006, Volume 9, Issue 1. (Entire issue)

Entire issue (large pdf file)

Student consumption of a la carte foods during school lunch meals

The purpose of this study was to evaluate students' lunch consumption compared to NSLP guidelines, the contribution of competitive foods to calorie intake at lunch, and the differences in nutrient and food group intake between the a la carte food consumers and non- a la carte food consumers.^ In Fall 2011, 1170 elementary and 440 intermediate students were observed anonymously during school lunch. The foods eaten, their source, grade level, and gender were recorded. All a la carte offerings met the Texas School Nutrition Policy.^ Differences in nutrient and food group intake by grade level and between students who consumed a la carte and those who did not were assessed using ANCOVA. A chi-squared analysis was conducted to evaluate differences in a la carte food consumption by grade level, gender, and the school's low income status.^ Average lunch intakes for elementary students were 457 (SD 164) calories for elementary students and 541 calories (SD 188) for intermediate students (p<0.001). 760 students (47%) consumed 937 a la carte foods, with the most often consumed items being chips (32%), ice cream (22%) and snack items (18%). Mean a la carte food intakes were 60 and 98 calories for elementary and intermediate schools respectively (p<0.001). Significantly more (p<0.000) intermediate students (34.3%) consumed a la carte items compared to elementary students (27.5%).^ Students who consumed a la carte foods had significantly higher intakes of calories (p<0.000), fat (p<0.000), sodium (p<0.002), fiber (p<0.000), added sugar (p<0.000), total grains (p<0.000), dessert foods (p<0.000), and snack chips (p<0.000) and lower intakes of vitamin A (p<0.001), iron (p<0.000), fruit (p<0.022), vegetables (p<0.031), milk (p<0.000), and juice (p<0.000) compared to students who did not eat a la carte foods.^ Although previous studies have found that reducing availability of unhealthy items at school decreased student consumption of these items, the results of this study indicate that even the strict guidelines set forth by the state of Texas are not sufficient to prevent increased caloric intake and poor nutrient intake. Strategies to improve student selection and consumption at school lunch when a la carte foods are available are warranted.^

Implication of bFGF signaling in lung carcinogenesis

A Western Array Screening system in conjunction with an in vitro lung carcinogenesis model, which consists of human bronchial epithelial (HBE) cells representing normal (NHBE), immortalized (BEAS-2B and 1799), transformed (1198), and tumorigenic (1170-I) was used to test the hypothesis that lung carcinogenesis involves specific changes in signaling proteins. Forty six proteins whose expression was upregulated by >2 fold and 23 proteins whose expression was downregulated by >2 fold in 1170-I compared to NHBE cells were identified. The levels of six proteins including bFGF (both intracellular and secreted), Akt and p70s6K in the PI3KJp70s6K pathway and the bFGF receptor (FGFR1) were upregulated in different stages of lung carcinogenesis. Akt activity and phospho-p70s6K were also increased in 1170-I compared to NHBE cells, suggesting that PI3K/p70s6K pathway is activated during lung carcinogenesis. bFGF treatment stimulated the growth of the 1170-I cells. Both tyrosine phosphorylation of FGFR1 and cell growth were inhibited in 1170-I cells after overexpression of dominant-negative(DN) FGFR1. Growth inhibition involved a G2 arrest related to decreased cdc2 activity, cdc25C downregulation, Wee1, p21(WAF1) and p27(Kip1) upregulation. Apoptosis was observed in tumorigenic but not in normal cells after overexpression of DNFGFR1. Confluent NHBE cells, were much less sensitive to the growth inhibition by DNFGFR1 compared to other cell lines analyzed. bFGF increased phospho-Akt and phospho-p70s6K in 1170-I cells. The Akt inhibitor LY294002 and the p70s6K inhibitor rapamycin inhibited bFGF-stimulated cell growth in 1170-I cells. Both agents downregulated the bFGF-induced increase in S phase by inducing G1 arrest. Also, LY294002 inhibited bFGF increased phospho-Akt, while both LY294002 and rapamycin inhibited bFGF increased phospho-p70s6K. Thus, cell proliferation stimulated by bFGF in 1170-I cells was at least partially mediated by PI3K/p70s6K pathway. Hsp90 was upregulated by bFGF in 1170-I cells. Its inhibitor geldanamycin inhibited the bFGF-stimulated growth via inducing apoptosis and G2 arrest through decreases in cdc2 expression/activity and p21 upregulation, and decreased Akt/phospho-Akt, p70s6K/phospho-p70s6K and Bad. Hsp90, p70s6K and Bad were found in the same complex, which may be important for signaling cell survival. Taken together, our study suggests that bFGF signaling, especially PI3K/p70s6K pathway, is important for lung carcinogenesis. ^