Lipids with long and very long chain polyenoic fatty acids: from cell localization to function

AVELDAÑO, MI

Villa Carlos Paz, Córdoba, 8-11 de noviembre

Congreso; XLIV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2008

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

LIPIDS WITH LONG AND VERY LONG CHAIN POLYENOIC FATTY ACIDS: FROM CELL LOCALIZATION TO FUNCTION Aveldaño, M.I. Instituto de Investigaciones Bioquímicas de Bahía Blanca, CONICET-UNS, Bahía Blanca, Argentina  In seminiferous tubules, spermatogenic cells proliferate and differentiate to produce spermatozoa, supported by Sertoli cells. Among their multiple functions, the latter phagocytize lipid-rich residual bodies that are normally formed in spermiogenesis as well as apoptotic bodies from germ cells that die from any cause. Glycerophospholipids (GPL) rich in PUFA (22:5n-6) and sphingomyelins (SM) rich in very long chain PUFA (28:4n-6 to 32:5n-6) belong to germ cells, as these lipids disappeared from the testis of fertile adult rats after these cells died as a result of irradiation, cryptorchidism, or doxorubicin. Surviving Sertoli cells efficiently maintained lipid homeostasis in the testis. They processed and disposed of materials arising from former germ cells, including free cholesterol and GPL, to make cholesterol esters rich in VLCPUFA and 22:5n-6. PUFA-GPL and VLCPUFA-SM (and ceramides) evolved with germ cell differentiation, part of the VLCPUFA becoming α-hydroxylated, to eventually compose spermatozoa. In the latter, GPL and SM species were distributed unevenly between tail and head, part of these lipids being hydrolyzed differentially after sperm capacitation and acrosomal exocytosis. Thus, specific lipids with unique fatty acids are created in the testis with the teleological objective of eventually produce the lipid metabolites that govern these male gamete-specific reactions