Poincyane Assis Prof.: Dr. Peter Lin BIO 475-01 – Seminar

1. Inhibition of Human Immunodeficiency Virus type 1 (HIV-1) transmission from mother-to-child through breastfeeding by the transforming growth factor β (TGF- β), a major cytokine in breast milk Poincyane Assis Prof.: Dr. Peter Lin BIO 475-01 – Seminar

2. Introduction • Three means of vertical transmission from mother-to-child (MTC) of Human Immunodeficiency Virus type 1 (HIV-1) • Transmission through breastfeeding is main concern. • Moriuchi and Moriuchi studied whether TGF- β influences HIV-1 expression in major breast milk cells such as mammary epithelial cells and macrophages.

3. Vertical Transmission of HIV-1 from MTC • Transplacentally during pregnancy • Birth canal during the delivery process • After birth through breast feeding

4. Treatment for Transplacental MTC Transmission • Methods that have been tested to either prevent or at least reduce the risk of MTC transmission while the fetus is protected by the amniotic sac: • Nevirapine and Zidovudine • Highly active antiretroviral therapy

5. “Treatment” for Birth Canal MTC Transmission • Early delivery by Cesarean sections http://hon.nucleusinc.com/imagescooked/564W.jpg

6. Why Emphasize on MTC Transmission through Breastfeeding? • Breast milk is important for a healthy development of a child’s immune system. • Alternative feeding is unaffordable in many developing countries. • Lack of clean water supply. http://www.cdc.gov/ncidod/diseases/hepatitis/b/education/images/slide_1.jpg

7. HIV-1 Transmission Rates in Infants of HIV-infected Mothers (Vermund, 2005)

8. The Million Dollars Question: IS THERE A WAY TO INHIBIT VERTICAL TRANSMISSION FROM MOTHER-TO-CHILD (MTC) THROUGH BREASTFEEDING?

9. The Answer is believed to be YES! • Moriuchi and Moriuchi studied whether TGF- β influences HIV-1 expression in major breast milk cells such as mammary epithelial cells and macrophages. • Transforming growth factor β (TGF- β), a major cytokine in breast milk, is thought to inhibit the vertical transmission of HIV-1 from MTC through breast milk in some cell types.

10. Materials and Methods • Single- or multiple-round viral replication assays. • Plasmids and Transfection. • Nuclear extracts and gel mobility shit assays. • Real-time RT-PCR.

11. Transforming growth factor β (TGF- β) • TGF- β is a major cytokine in breast milk. • TGF- β families of cytokine regulate many aspects of cellular functions such as: • cell growth and differentiation • Morphogenesis • Apoptosis • Inhibits proliferation of epithelial cells, T-lymphocytes and macrophages as well as other cells.

12. TGF- β and HIV-1 • Data implicate bifunctional activity of TGF- β in mother-to-child transmission of HIV-1. • TGF- β acts as an anti-HIV-1 or pro-HIV-1 factor, depending on: • cell type • virus strain • timing of treatment • combination of other factors

13. What is a Cytokine? • A regulatory protein • Repressor • Inducer • Released by cells of the immune system • Acts as intercellular mediators in the generation of an immune response

14. TGF- β as a Repressor

15. Composition of Breast Milk • HIV-1 infected cells and cell-free virions. • Breast milk contains soluble factors that exert important functions. • Milk whey components: • Lactoferrin and prostaglandin E have been shown to inhibit HIV-1 replication. • The cell composition of breast milk changes throughout the lactation period: • Colostrum (2 weeks after delivery): rich in cells, such as macrophages (50 to 75%), neutrophils (20 to 40%) and lymphocytes (3 to 10%) • Mature milk (more than 2 weeks after delivery) : mainly mammary epithelial cells

16. HIV-1 Strains • HIV-1 strains are classified according to their coreceptor usage: • R5-tropic virus utilizes CCR5 as an entry coreceptor. • X4-tropic virus utilizes CXCR4 as an entry coreceptor.

17. Sources of the Virus in Breast Milk • Mammary epithelial cells, MCF-7 • Susceptible to X4-tropic HIV-1 strain • White Blood Cells: • macrophages • Susceptible to R5-tropic HIV-1 strain • lymphocytes

18. Mammary Epithelial MCF-7 Cells • Does exposure to milk whey or its components and TGF- β influence the susceptibility of mammary epithelial MCF-7 cells to HIV-1?

19. TGF- β Inhibited HIV-1Infection of MCF-7 Cells

20. Macrophages • What are the effects of milk whey or TGF- β on HIV-1 infection of macrophages, another major source of HIV-1 in breast milk?

21. The Effects of Milk Whey or TGF- β on HIV-1 infection of Macrophages

22. Lymphocytes • How does milk whey or TGF- β on HIV-1 infection of Lymphocytes?

23. The Effects of Milk Whey or TGF- β on HIV-1 infection of Lymphocytes

24. Results • TGF- β suppressed HIV-1 infection of mammary epithelial MCF-7 cells but favored that of macrophages. • TGF- β enhanced HIV-1 infection of lymphocytes at 10 ng/ml or lower, but suppressed it at 1 ng/ml or higher.Since the TGF- β concentration in breast milk is as high as 1 to 2 ng/ml, HIV-1 infection of lymphocytes may be inhibited in this setting.

25. Conclusions • Susceptibility to HIV-1 strains differs in macrophages, lymphocytes and mammary epithelial cells in breast milk. • It remains unclear which cell type plays a major role in mother-to-child transmission. • TGF- β was identified as a bifunctional modulator of HIV-1 infection. • In lymphocytes TGF- β appears to have dichotomous effects on HIV-1 infection. • It appears that the net effect of breast milk on HIV-1 infection depends on the balance of those pro- and anti-HIV-1 factors.

26. References • Bajunirwe, F., Massaquoi, I., Asiimwe, S., Kamya M.R., Arts, E.J., Whalen, C.C. 2004. Effectiveness of nevirapine and zidovudine in a pilot program for the prevention of mother-to-child transmission of HIV-1 in Uganda. Afr. Health Sci. 4:146-154. • European Collaborative Study. 2005. Mother-to-child transmission of HIV infection in the era of highly active antiretroviral therapy. Clinical Infectious Diseases. 40:458-465. • Hagmann, M. 1999. Early Cesarean Saves Infants From HIV. Science Now. Accessed on February 14, 2005 from Early Cesarean Saves Infants From HIV -- 1999 (128) 4 – sciencenow.htm • Henderson, G.J., Hoffman, N.G., Ping, L.H., Fiscus, S.A., Hoffman, I.F., Kitrinos, K.M., Banda, T., Martinson, F.E., Kazembe, P.N., Chilongozi, D.A., Cohen, M.S., Swanstrom, R. 2004. HIV-1 populations in blood and breast milk are similar. Virology. 330:295-303. • Li, J.M., Shen, X., Hu, P.P., Wang, X.F. 1998. Transforming growth factor beta stimulates the human immunodeficiency virus 1 enhancer and requires NF-kappaB activity. Molecular and Cell Biology. 18:110-121. • Moriuchi, M. and H. Moriuchi. 2004. Cell-type-dependent effect of transforming growth factor beta, a major cytokine in breast milk, on human immunodeficiency virus type 1 infection of mammary epithelial MCF-7 cells or macrophages. Journal of Virology. 78:13046-13052. • Spector, Stephen A. 2001. Mother-to-infant transmission of HIV-1: the placenta fights back. Journal of Clinical Investigation. 107: 267-269. • Vermund, S.H. 2005. Prevention of Mother-to-Child Transmission of HIV in Africa. Top HIV Med. 12:130-134.

27. QUESTIONS??? ? ? ? ? ? ? ? ? ?