Biology subjects

Pioli, K. T.

Publications and source records attributed to Pioli, K. T..

4 recordsLinked to original sources

bioRxiv2024

A hepatocyte-specific cytochrome c oxidase deficiency in mice leads to a lymphopenia owing to deficiencies in bone marrow progenitors

Mutations that negatively impact mitochondrial function are highly prevalent in humans and lead to disorders with a wide spectrum of disease phenotypes, including deficiencies in immune cell development and/or function. Previous analyses of mice with a hepatocyte-specific cytochrome c oxidase (COX) deficiency revealed an unexpected peripheral blood leukopenia associated with splenic and thymic atrophy. Here, we use mice with a hepatocyte-specific deletion of the COX assembly factor Sco1 to show that metabolic defects extrinsic to the hematopoietic compartment lead to a pan-lymphopenia represented by severe losses in both B and T cells. We further demonstrate that immune defects in these mice are associated with the loss of bone marrow lymphoid progenitors common to both lineages and early signs of autoantibody-mediated autoimmunity. Our findings collectively point to a significant role for hepatocyte dysfunction as an instigator of immunodeficiency in patients with congenital mitochondrial defects who suffer from chronic or recurrent infections.

immunology↗

bioRxiv2024

Jchain-DTR Mice Allow for Diphtheria Toxin-Mediated Depletion ofAntibody-Secreting Cells and Evaluation of Their Differentiation Kinetics

Antibody-secreting cells (ASCs) are generated following B cell activation and constitutively secrete antibodies. As such, ASCs play key roles in humoral immunity, including responses to pathogens, vaccination, and homeostatic clearance of cell debris. Therefore, understanding basic tenents of ASC biology such as their differentiation kinetics following B cell stimulation is of importance. We developed a mouse model which expresses simian heparin-binding EGF-like growth factor (HBEGF) [diphtheria toxin receptor (DTR)] under the control of the endogenous Jchain locus (J-DTR). ASCs from J-DTR mice expressed high levels of cell surface DTR and were acutely depleted following diphtheria toxin treatment. Furthermore, proof-of-principle experiments demonstrated the ability to use J-DTR mice to track ASC reconstitution following depletion in the spleen, bone marrow and thymus which represent sites of ASC generation and/or retention. Overall, J-DTR mice provide a new and highly effective genetic tool allowing for the study of ASC biology in a wide range of potential applications.

immunology↗

bioRxiv2022

Thymus Antibody-Secreting Cells Represent a Tissue Specific Population That Possess an Activated Cellular Phenotype

Antibody-secreting cells (ASCs) are key contributors to humoral immunity through immunoglobulin production and the potential to be long-lived. ASCs have been recently identified in the thymus (THY) which is of interest as autoreactive THY B cells regulate T cell tolerance. Here, we showed that the young female THY was skewed towards higher production of ASCs relative to males. However, these differences disappeared with age. Intravenous labeling combined with blockade of CD154(CD40L) suggested that THY ASCs were generated in situ in a T cell dependent fashion. Single cell RNA-sequencing revealed that THY ASCs possessed a transcriptional signature indicative of interferon signaling and activation. Flow cytometry confirmed that THY ASCs had increased levels of Toll-like receptor 7 as well as the activation markers CD69 and major histocompatibility class II. Overall, THY ASCs are a unique population that require further investigation to fully appreciate their biological significance.

immunology↗

bioRxiv2022

Intracellular flow cytometry staining of antibody-secreting cells using phycoerythrin-conjugated antibodies: pitfalls and solutions

Antibody-secreting cells are terminally differentiated B cells that play a critical role in humoral immunity through immunoglobulin secretion along with possessing the potential to be long-lived. It is now appreciated that antibody-secreting cells regulate multiple aspects of biology through the secretion of various cytokines. In this regard, intracellular flow cytometry is a key tool used to assess the presence of intracellular proteins such as cytokines and transcription factors. Here, we showed that the use of phycoerythrin-containing antibody conjugates led to a false interpretation of antibody-secreting cell intracellular protein expression compared to other cell types. This was mainly due to the inappropriate retention of these antibodies specifically within antibody-secreting cells. Furthermore, we demonstrated how to reduce this retention which allowed for a more accurate comparison of intracellular protein expression between antibody-secreting cells and other cell types such as B lymphocytes. Using this methodology, our data revealed that spleen antibody-secreting cells expressed Toll-like receptor 7 as well as the pro-form of the inflammatory cytokine interleukin-1{beta}.

immunology↗