The intriguing ultrastructure of lipid body organelles within activated macrophages.
Macrophages are widely distributed immune system cells with essential functions in tissue homeostasis, apoptotic cell clearance, and first defense in infections. A distinguishing feature of activated macrophages participating in different situations such as inflammatory and metabolic diseases is the presence of increased numbers of lipid-rich organelles, termed lipid bodies (LBs) or lipid droplets, in their cytoplasm. LBs are considered structural markers of activated macrophages and are involved in different functions such as lipid metabolism, intracellular trafficking, and synthesis of inflammatory mediators. In this review, we revisit the distinct morphology of LB organelles actively formed within macrophages in response to infections and cell clearance, taking into account new insights provided by ultrastructural studies. We also discuss the LB interactions within macrophages, revealed by transmission electron microscopy, with a focus on the remarkable LB-phagosome association and discuss potential links between structural aspects and function.
1Laboratory of Cellular Biology,Department of Biology,Federal University of Juiz de Fora (UFJF),Juiz de Fora,MG 36036-900,Brazil.
Felipe F
FF
Dias
1Laboratory of Cellular Biology,Department of Biology,Federal University of Juiz de Fora (UFJF),Juiz de Fora,MG 36036-900,Brazil.
Victor C
VC
Zarantonello
2Laboratory of Structural Biology and Reproduction,Federal University of Minas Gerais (UFMG),Belo Horizonte,MG 31270-901,Brazil.
Gleydes G
GG
Parreira
2Laboratory of Structural Biology and Reproduction,Federal University of Minas Gerais (UFMG),Belo Horizonte,MG 31270-901,Brazil.
Hélio
H
Chiarini-Garcia
1Laboratory of Cellular Biology,Department of Biology,Federal University of Juiz de Fora (UFJF),Juiz de Fora,MG 36036-900,Brazil.
Rossana C N
RC
Melo
D000818:Animals; D003593:Cytoplasm / Q000648:ultrastructure*; D006801:Humans; D066292:Lipid Droplets / Q000648:ultrastructure*; D008262:Macrophage Activation; D008264:Macrophages / Q000502:physiology* / Q000648:ultrastructure*