[30] GATA-2 AND GATA-3 GENES ARE INVOLVED IN HUMAN ADIPOCYTE DIFFERENTIATION AND THEIR EXPRESSION IS ALTERED BY PROTEASE INHIBITORS

5th International Workshop on Adverse Drug Reactions and Lipodystrophy in HIV

8–11 July 2003, Le Meridien Montparnasse, Paris, France

GATA-2 AND GATA-3 GENES ARE INVOLVED IN HUMAN ADIPOCYTE DIFFERENTIATION AND THEIR EXPRESSION IS ALTERED BY PROTEASE INHIBITORS

Antiviral Therapy 2003; 8:L26) (abstract 30)

A Riva¹, S Ammannato¹, B Zanone Poma¹, P Fedeli¹, D Mologni¹, L Rovati², D Foschi³ and M Galli¹
¹Institute of infectious Diseases and Tropical Medicine, University of Milan, Italy; ²Plastic Surgery Unit, San Gerardo Hospital, University of Milan-Bicocca, Italy; and ³San Siro Clinical Institute; Universitiy of Milan, Italy

BACKGROUND: HIV-1 protease inhibitors were shown to inhibit adipocyte differentiation of cultured cells; the mechanisms involved in such alteration are still debated. In the murine model it has been demonstrated that GATA-2 and GATA-3 transcription factors are specifically expressed in white adipocyte precursors and their down-regulation sets the stage for terminal differentiation. Constitutive GATA-2 and GATA-3 expression suppressed adipocyte differentiation and trapped cells at the preadipocytes stage. This effect is mediated, at least in part, through the direct suppression of PPAR-γ. No information on GATA-2 and 3 genes is currently available regarding human adipocyte differentiation.

OBJECTIVE: To evaluate mRNA expression of GATA- 2 and GATA-3 in primary human preadipocytes and adipocytes from HIV-1 seronegative healthy controls and from HIV-1-infected patients who developed lipodystrophy, and to examine the effects of the HIV-1 protease inhibitors on adipogenesis.

METHODS: Preadipocytes were isolated from five healthy controls and five HIV-1-positive patients by dissection and incubation with digestion buffer. Primary human preadipocytes were cultured for 21 days in differentiation medium (DMEM/F12 HAM with dexamethasone, insulin and IBMX) supplemented with or without antiretroviral drugs. Total cellular RNA was extracted and purified from cultured preadipocytes and adipocytes. An RT-PCR assay was developed for semiquantitative analysis.

RESULTS: GATA-2 mRNA is expressed constitutively in human preadipocytes and it is down-regulated during differentiation, as in the murine model. On the contrary, GATA-3 mRNA is up-regulated during the preadipocyte–adipocyte transition. GATA-2 and GATA- 3 expression did not differ between HIV-1-negative control and HIV-1-positive patients at isolation. When human preadipocytes are differentiated in the presence of protease inhibitors, they do not down-regulate GATA-2 and consistently PPAR-γ is not induced and differentiation is impaired. GATA-3 is not differentially expressed in adipocytes differentiated with or without drugs.

CONCLUSIONS: Our data demonstrate that the regulation of GATA-2 and GATA-3 protein is essential to human preadipocyte–adipocyte transition. The differentiation of primary preadipocytes in HIV-infected patients and in healthy controls is associated with down-regulation of GATA-2 expression and up-regulation of GATA-3. Protease inhibitors impair adipocyte differentiation at an early step of adipocyte differentiation probably interfering with GATA-2 expression.

Presenting author: A Riva

2003-07-08
30

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