{"id":{"repo_id":"wustl","oai_identifier":"oai:openscholarship.wustl.edu:etd-1244"},"canonical_url":"https://search.dev.ndltd.org/etd/wustl/oai:openscholarship.wustl.edu:etd-1244","repository":{"repo_id":"wustl","name":"Washington University in St. Louis","base_url":"https://openscholarship.wustl.edu/do/oai/"},"display":{"title":"The Functions of Autophagy Genes in Lymphocytes and Osteoclasts","abstract":"Macroautophagy: herein autophagy) is a process by which cells degrade long-lived proteins and organelles. The autophagy pathway and autophagy genes have been implicated in many functions in the cell such as protecting against metabolic stress, degrading damaged organelles, and regulating vesicular trafficking. To study the role of autophagy in primary cells with important physiologic functions, we generated mice lacking essential autophagy genes in B lymphocytes, T lymphocytes, and osteoclasts. We found that the essential autophagy gene <italic>Atg5</italic> was important for B cell development and for the maintenance of B-1a B cell numbers but not peripheral B-2 B cell numbers. In T cells, deletion of the essential autophagy genes <italic>Atg5</italic> or <italic>Atg7</italic> resulted in decreased thymocyte and peripheral T cell numbers <italic>in vivo</italic> and a decrease in cell proliferation <italic>in vitro</italic>. Autophagy genes play a critical role in T cell homeostasis, but do not appear important for peripheral B-2 B cell homeostasis <italic>in vivo</italic>. Whole-genome transcriptional profiling of <italic>Atg5</italic>-deficient and wild-type thymocytes suggested abnormalities in mitochondria in the absence of <italic>Atg5</italic>. We confirmed this observation by demonstrating that peripheral <italic>Atg5</italic>-deficient T cells had an increase in mitochondrial mass that correlated with increased Annexin-V staining in these cells. We speculate that autophagy is required in T cells for the removal of damaged or aged mitochondria and that excess mitochondria contribute to increased cell death in autophagy-deficient T cells. In contrast to lymphocytes, deletion of autophagy genes in osteoclasts did not result in dramatic abnormalities in cell development. However, the biochemical pathway necessary for autophagy was critical for directional secretion in osteoclasts. We found that the autophagosome marker LC3 localized to the resorptive microenvironment in osteoclasts. Deleting <italic>Atg5</italic> or <italic>Atg7</italic> or overexpressing a dominant negative mutant of ATG4B to inhibit LC3 conjugation reduced localization of lysosomal markers at the resorptive surface and decreased bone resorption <italic>in vitro</italic>. Furthermore, mice lacking <italic>Atg5</italic> in osteoclasts and other myeloid-lineage cells were protected from ovarectomy-induced bone loss, a mouse model of osteoporosis. Together, these studies demonstrate that autophagy genes are important in cell development, survival, mitochondrial maintenance, and directional secretion in physiologically important, primary mammalian cells.","abstract_html":"Macroautophagy: herein autophagy) is a process by which cells degrade long-lived proteins and organelles. The autophagy pathway and autophagy genes have been implicated in many functions in the cell such as protecting against metabolic stress, degrading damaged organelles, and regulating vesicular trafficking. To study the role of autophagy in primary cells with important physiologic functions, we generated mice lacking essential autophagy genes in B lymphocytes, T lymphocytes, and osteoclasts. We found that the essential autophagy gene &lt;italic&gt;Atg5&lt;/italic&gt; was important for B cell development and for the maintenance of B-1a B cell numbers but not peripheral B-2 B cell numbers. In T cells, deletion of the essential autophagy genes &lt;italic&gt;Atg5&lt;/italic&gt; or &lt;italic&gt;Atg7&lt;/italic&gt; resulted in decreased thymocyte and peripheral T cell numbers &lt;italic&gt;in vivo&lt;/italic&gt; and a decrease in cell proliferation &lt;italic&gt;in vitro&lt;/italic&gt;. Autophagy genes play a critical role in T cell homeostasis, but do not appear important for peripheral B-2 B cell homeostasis &lt;italic&gt;in vivo&lt;/italic&gt;. Whole-genome transcriptional profiling of &lt;italic&gt;Atg5&lt;/italic&gt;-deficient and wild-type thymocytes suggested abnormalities in mitochondria in the absence of &lt;italic&gt;Atg5&lt;/italic&gt;. We confirmed this observation by demonstrating that peripheral &lt;italic&gt;Atg5&lt;/italic&gt;-deficient T cells had an increase in mitochondrial mass that correlated with increased Annexin-V staining in these cells. We speculate that autophagy is required in T cells for the removal of damaged or aged mitochondria and that excess mitochondria contribute to increased cell death in autophagy-deficient T cells. In contrast to lymphocytes, deletion of autophagy genes in osteoclasts did not result in dramatic abnormalities in cell development. However, the biochemical pathway necessary for autophagy was critical for directional secretion in osteoclasts. We found that the autophagosome marker LC3 localized to the resorptive microenvironment in osteoclasts. Deleting &lt;italic&gt;Atg5&lt;/italic&gt; or &lt;italic&gt;Atg7&lt;/italic&gt; or overexpressing a dominant negative mutant of ATG4B to inhibit LC3 conjugation reduced localization of lysosomal markers at the resorptive surface and decreased bone resorption &lt;italic&gt;in vitro&lt;/italic&gt;. Furthermore, mice lacking &lt;italic&gt;Atg5&lt;/italic&gt; in osteoclasts and other myeloid-lineage cells were protected from ovarectomy-induced bone loss, a mouse model of osteoporosis. Together, these studies demonstrate that autophagy genes are important in cell development, survival, mitochondrial maintenance, and directional secretion in physiologically important, primary mammalian cells.","abstract_has_math":false,"creators":["Miller, Brian"],"institution":null,"degree_name":"Doctor of Philosophy (PhD)","degree_level":"Dissertation","degree_discipline":"Biology and Biomedical Sciences: Immunology","degree_department":null,"school":null,"contributors":["Herbert Virgin"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-01-01T08:00:00Z","date_published":"2011-01-01T08:00:00Z","updated_at":"2026-07-24T06:13:23Z","subjects":["Immunology","Cellular Biology","Autophagy","B Lymphocyte","Osteoclast","T Lymphocyte"],"languages":["English (en)"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier.doi","label":"DOI","values":["https://doi.org/10.7936/K7M043DZ"],"render_values":[{"text":"https://doi.org/10.7936/K7M043DZ","href":"https://doi.org/10.7936/K7M043DZ","code":true}]}]},"links":{"outbound_url":"https://openscholarship.wustl.edu/etd/245","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Herbert Virgin"]},{"key":"dc:creator","label":"Author","values":["Miller, Brian"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2010-01-01T08:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Biology and Biomedical Sciences: Immunology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Immunology","Cellular Biology","Autophagy","B Lymphocyte","Osteoclast","T Lymphocyte"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English (en)"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://openscholarship.wustl.edu/etd/245"]},{"key":"dc:identifier.doi","label":"DOI","values":["https://doi.org/10.7936/K7M043DZ"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Macroautophagy: herein autophagy) is a process by which cells degrade long-lived proteins and organelles. The autophagy pathway and autophagy genes have been implicated in many functions in the cell such as protecting against metabolic stress, degrading damaged organelles, and regulating vesicular trafficking. To study the role of autophagy in primary cells with important physiologic functions, we generated mice lacking essential autophagy genes in B lymphocytes, T lymphocytes, and osteoclasts. We found that the essential autophagy gene <italic>Atg5</italic> was important for B cell development and for the maintenance of B-1a B cell numbers but not peripheral B-2 B cell numbers. In T cells, deletion of the essential autophagy genes <italic>Atg5</italic> or <italic>Atg7</italic> resulted in decreased thymocyte and peripheral T cell numbers <italic>in vivo</italic> and a decrease in cell proliferation <italic>in vitro</italic>. Autophagy genes play a critical role in T cell homeostasis, but do not appear important for peripheral B-2 B cell homeostasis <italic>in vivo</italic>. Whole-genome transcriptional profiling of <italic>Atg5</italic>-deficient and wild-type thymocytes suggested abnormalities in mitochondria in the absence of <italic>Atg5</italic>. We confirmed this observation by demonstrating that peripheral <italic>Atg5</italic>-deficient T cells had an increase in mitochondrial mass that correlated with increased Annexin-V staining in these cells. We speculate that autophagy is required in T cells for the removal of damaged or aged mitochondria and that excess mitochondria contribute to increased cell death in autophagy-deficient T cells. In contrast to lymphocytes, deletion of autophagy genes in osteoclasts did not result in dramatic abnormalities in cell development. However, the biochemical pathway necessary for autophagy was critical for directional secretion in osteoclasts. We found that the autophagosome marker LC3 localized to the resorptive microenvironment in osteoclasts. Deleting <italic>Atg5</italic> or <italic>Atg7</italic> or overexpressing a dominant negative mutant of ATG4B to inhibit LC3 conjugation reduced localization of lysosomal markers at the resorptive surface and decreased bone resorption <italic>in vitro</italic>. Furthermore, mice lacking <italic>Atg5</italic> in osteoclasts and other myeloid-lineage cells were protected from ovarectomy-induced bone loss, a mouse model of osteoporosis. Together, these studies demonstrate that autophagy genes are important in cell development, survival, mitochondrial maintenance, and directional secretion in physiologically important, primary mammalian cells."]},{"key":"dc:title","label":"Title","values":["The Functions of Autophagy Genes in Lymphocytes and Osteoclasts"]}]}],"canonical_facts":{"dc:contributor":["Herbert Virgin"],"dc:creator":["Miller, Brian"],"dc:date.available":["2010-01-01T08:00:00Z"],"dc:description.abstract":["Macroautophagy: herein autophagy) is a process by which cells degrade long-lived proteins and organelles. The autophagy pathway and autophagy genes have been implicated in many functions in the cell such as protecting against metabolic stress, degrading damaged organelles, and regulating vesicular trafficking. To study the role of autophagy in primary cells with important physiologic functions, we generated mice lacking essential autophagy genes in B lymphocytes, T lymphocytes, and osteoclasts. We found that the essential autophagy gene <italic>Atg5</italic> was important for B cell development and for the maintenance of B-1a B cell numbers but not peripheral B-2 B cell numbers. In T cells, deletion of the essential autophagy genes <italic>Atg5</italic> or <italic>Atg7</italic> resulted in decreased thymocyte and peripheral T cell numbers <italic>in vivo</italic> and a decrease in cell proliferation <italic>in vitro</italic>. Autophagy genes play a critical role in T cell homeostasis, but do not appear important for peripheral B-2 B cell homeostasis <italic>in vivo</italic>. Whole-genome transcriptional profiling of <italic>Atg5</italic>-deficient and wild-type thymocytes suggested abnormalities in mitochondria in the absence of <italic>Atg5</italic>. We confirmed this observation by demonstrating that peripheral <italic>Atg5</italic>-deficient T cells had an increase in mitochondrial mass that correlated with increased Annexin-V staining in these cells. We speculate that autophagy is required in T cells for the removal of damaged or aged mitochondria and that excess mitochondria contribute to increased cell death in autophagy-deficient T cells. In contrast to lymphocytes, deletion of autophagy genes in osteoclasts did not result in dramatic abnormalities in cell development. However, the biochemical pathway necessary for autophagy was critical for directional secretion in osteoclasts. We found that the autophagosome marker LC3 localized to the resorptive microenvironment in osteoclasts. Deleting <italic>Atg5</italic> or <italic>Atg7</italic> or overexpressing a dominant negative mutant of ATG4B to inhibit LC3 conjugation reduced localization of lysosomal markers at the resorptive surface and decreased bone resorption <italic>in vitro</italic>. Furthermore, mice lacking <italic>Atg5</italic> in osteoclasts and other myeloid-lineage cells were protected from ovarectomy-induced bone loss, a mouse model of osteoporosis. Together, these studies demonstrate that autophagy genes are important in cell development, survival, mitochondrial maintenance, and directional secretion in physiologically important, primary mammalian cells."],"dc:identifier":["https://openscholarship.wustl.edu/etd/245"],"dc:identifier.doi":["https://doi.org/10.7936/K7M043DZ"],"dc:language":["English (en)"],"dc:subject":["Immunology","Cellular Biology","Autophagy","B Lymphocyte","Osteoclast","T Lymphocyte"],"dc:title":["The Functions of Autophagy Genes in Lymphocytes and Osteoclasts"],"thesis:degree_discipline":["Biology and Biomedical Sciences: Immunology"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Doctor of Philosophy (PhD)"]},"updated_at":"2026-07-24T06:13:23Z"}