Mechanistic roles of autophagy in hematopoietic differentiation

Autophagy is increasingly recognized for its active role in development and differentiation. In particular, its role in the differentiation of hematopoietic cells has been extensively studied, likely because blood cells are accessible, easy to identify and purify and their progenitor tree is well defined. This review aims to discuss the mechanisms by which autophagy impacts on differentiation, using hematopoietic cell types as examples. Autophagy’s roles include the remodeling during terminal differentiation, the maintenance of a long-lived cell type, and the regulation of the balance between self-renewal and quiescence in stem-like cells. We discuss and compare the mechanistic roles of autophagy, such as prevention of apoptosis, supply of energy metabolites and metabolic adaption, selective degradation of organelles and of regulatory factors

Assessing Autophagy During Retinoid Treatment of Breast Cancer Cells.

Retinoids are derived from vitamin A through a multi-step process. Within a target cell, retinoids regulate gene expression by activating the retinoid acid receptors (RAR) and retinoid x receptors (RXR), which are ligand-dependent transcription factors. Besides its therapeutic use in dermatological disorders, all-trans retinoic acid (ATRA) is successfully utilized to treat acute promyelocytic leukemia (APL) patients. The use of ATRA in APL patients is the first example of clinically useful differentiation therapy. Therapeutic strategies aiming at cancer cell differentiation have great potential for solid tumors, including breast cancer. The few clinical studies conducted with ATRA in breast cancer are rather disappointing. However, these studies did not take into account the heterogeneity of the disease and were conducted on unselected cohorts of patients.We recently showed that ATRA treatment of breast cancer cells induces autophagy, a highly conserved process aiming at degrading and recycling superfluous or harmful cellular components. In addition, autophagy inhibition significantly increases the therapeutic activity of ATRA. This finding is of fundamental importance, since autophagy has a dual role in cancer. Whereas autophagy may be a protective mechanism during the initial phases of cancer development, it may support cancer cell survival in already established tumors. Furthermore, autophagy can lower or enhance therapeutic efficiency, depending on the tumor type and the anticancer agent considered. Therefore, it is important to investigate the role of autophagy in the context of specific tumors and therapeutic approaches. Accurate autophagy studies are challenging given the dynamic nature of the process and the difficulty of measuring the rate of autophagosome degradation (autophagic flux). In this chapter, we provide protocols for a careful assessment of the autophagic flux in ATRA treated 2D and 3D breast cancer cultures

Transcriptomic analysis of the autophagy machinery in crustaceans

Background: The giant freshwater prawn, Macrobrachium rosenbergii, is a decapod crustacean that is commercially important as a food source. Farming of commercial crustaceans requires an efficient management strategy because the animals are easily subjected to stress and diseases during the culture. Autophagy, a stress response process, is well-documented and conserved in most animals, yet it is poorly studied in crustaceans. Results: In this study, we have performed an in silico search for transcripts encoding autophagy-related (Atg) proteins within various tissue transcriptomes of M. rosenbergii. Basic Local Alignment Search Tool (BLAST) search using previously known Atg proteins as queries revealed 41 transcripts encoding homologous M. rosenbergii Atg proteins. Among these Atg proteins, we selected commonly used autophagy markers, including Beclin 1, vacuolar protein sorting (Vps) 34, microtubule-associated proteins 1A/1B light chain 3B (MAP1LC3B), p62/sequestosome 1 (SQSTM1), and lysosomal-associated membrane protein 1 (Lamp-1) for further sequence analyses using comparative alignment and protein structural prediction. We found that crustacean autophagy marker proteins contain conserved motifs typical of other animal Atg proteins. Western blotting using commercial antibodies raised against human Atg marker proteins indicated their presence in various M. rosenbergii tissues, while immunohistochemistry localized Atg marker proteins within ovarian tissue, specifically late stage oocytes. Conclusions: This study demonstrates that the molecular components of autophagic process are conserved in crustaceans, which is comparable to autophagic process in mammals. Furthermore, it provides a foundation for further studies of autophagy in crustaceans that may lead to more understanding of the reproduction- and stress-related autophagy, which will enable the efficient aquaculture practices